| 1. |
Michiko Itoh, Atsushi Tamura, Sayaka Kanai, Miyako Tanaka, Yohei Kanamori, Ibuki Shirakawa, Ayaka Ito, Yasuyoshi Oka, Isao Hidaka, Taro Takami, Yasushi Honda, Mitsuyo Maeda, Yasuyuki Saito, Yoji Murata, Takashi Matozaki, Atsushi Nakajima, Yosky Kataoka, Tomoo Ogi, Yoshihiro Ogawa, Takayoshi Suganami, Lysosomal cholesterol overload in macrophages promotes liver fibrosis in a mouse model of NASH., The Journal of experimental medicine, 10.1084/jem.20220681, 220, 11, 2023.11, Accumulation of lipotoxic lipids, such as free cholesterol, induces hepatocyte death and subsequent inflammation and fibrosis in the pathogenesis of nonalcoholic steatohepatitis (NASH). However, the underlying mechanisms remain unclear. We have previously reported that hepatocyte death locally induces phenotypic changes in the macrophages surrounding the corpse and remnant lipids, thereby promoting liver fibrosis in a murine model of NASH. Here, we demonstrated that lysosomal cholesterol overload triggers lysosomal dysfunction and profibrotic activation of macrophages during the development of NASH. β-cyclodextrin polyrotaxane (βCD-PRX), a unique supramolecule, is designed to elicit free cholesterol from lysosomes. Treatment with βCD-PRX ameliorated cholesterol accumulation and profibrotic activation of macrophages surrounding dead hepatocytes with cholesterol crystals, thereby suppressing liver fibrosis in a NASH model, without affecting the hepatic cholesterol levels. In vitro experiments revealed that cholesterol-induced lysosomal stress triggered profibrotic activation in macrophages predisposed to the steatotic microenvironment. This study provides evidence that dysregulated cholesterol metabolism in macrophages would be a novel mechanism of NASH.. |
| 2. |
Ryuji Ohue-Kitano, Hazuki Nonaka, Akari Nishida, Yuki Masujima, Daisuke Takahashi, Takako Ikeda, Akiharu Uwamizu, Miyako Tanaka, Motoyuki Kohjima, Miki Igarashi, Hironori Katoh, Tomohiro Tanaka, Asuka Inoue, Takayoshi Suganami, Koji Hase, Yoshihiro Ogawa, Junken Aoki, Ikuo Kimura, Medium-chain fatty acids suppress lipotoxicity-induced hepatic fibrosis via the immunomodulating receptor GPR84., JCI insight, 10.1172/jci.insight.165469, 8, 2, 2023.01, Medium-chain triglycerides (MCTs), which consist of medium-chain fatty acids (MCFAs), are unique forms of dietary fat with various health benefits. GPR84 acts as a receptor for MCFAs (especially C10:0 and C12:0); however, GPR84 is still considered an orphan receptor, and the nutritional signaling of endogenous and dietary MCFAs via GPR84 remains unclear. Here, we showed that endogenous MCFA-mediated GPR84-signaling protected hepatic functions from diet-induced lipotoxicity. Under high-fat diet (HFD) conditions, GPR84-deficient mice exhibited non-alcoholic steatohepatitis (NASH) and the progression of hepatic fibrosis but not steatosis. With markedly increased hepatic MCFA levels under HFD, GPR84 suppressed lipotoxicity-induced macrophage over-activation. Thus, GPR84 is an immunomodulating receptor that suppresses excessive dietary fat intake-induced toxicity by sensing increases in MCFAs. Additionally, administering MCTs, MCFAs (C10:0 or C12:0, but not C8:0), or GPR84 agonists effectively impreoved NASH in mouse models. Exogenous GPR84 stimulation is therefore a potential strategy for treating NASH.. |
| 3. |
Kensuke Shibata, Chihiro Motozono, Masamichi Nagae, Takashi Shimizu, Eri Ishikawa, Daisuke Motooka, Daisuke Okuzaki, Yoshihiro Izumi, Masatomo Takahashi, Nao Fujimori, James B Wing, Takahide Hayano, Yoshiyuki Asai, Takeshi Bamba, Yoshihiro Ogawa, Makoto Furutani-Seiki, Mutsunori Shirai, Sho Yamasaki, Symbiotic bacteria-dependent expansion of MR1-reactive T cells causes autoimmunity in the absence of Bcl11b., Nature communications, 10.1038/s41467-022-34802-8, 13, 1, 6948-6948, 2022.11, MHC class I-related protein 1 (MR1) is a metabolite-presenting molecule that restricts MR1-reactive T cells including mucosal-associated invariant T (MAIT) cells. In contrast to MAIT cells, the function of other MR1-restricted T cell subsets is largely unknown. Here, we report that mice in which a T cell-specific transcription factor, B-cell lymphoma/leukemia 11B (Bcl11b), was ablated in immature thymocytes (Bcl11b∆iThy mice) develop chronic inflammation. Bcl11b∆iThy mice lack conventional T cells and MAIT cells, whereas CD4+IL-18R+ αβ T cells expressing skewed Traj33 (Jα33)+ T cell receptors (TCR) accumulate in the periphery, which are necessary and sufficient for the pathogenesis. The disorders observed in Bcl11b∆iThy mice are ameliorated by MR1-deficiency, transfer of conventional T cells, or germ-free conditions. We further show the crystal structure of the TCR expressed by Traj33+ T cells expanded in Bcl11b∆iThy mice. Overall, we establish that MR1-reactive T cells have pathogenic potential.. |
| 4. |
Takashi Kadowaki, Rina Chin, Akichika Ozeki, Takeshi Imaoka, Yoshihiro Ogawa, Safety and efficacy of tirzepatide as an add-on to single oral antihyperglycaemic medication in patients with type 2 diabetes in Japan (SURPASS J-combo): a multicentre, randomised, open-label, parallel-group, phase 3 trial., The lancet. Diabetes & endocrinology, 10.1016/S2213-8587(22)00187-5, 10, 9, 634-644, 2022.09, BACKGROUND: Due to potential ethnic differences in the pathophysiology of type 2 diabetes, new therapeutics need to be evaluated in Japanese patients. We aimed to assess the safety and glycaemic efficacy of tirzepatide as an add-on treatment in Japanese patients with type 2 diabetes who had inadequate glycaemic control with stable doses of various oral antihyperglycaemic monotherapies. METHODS: This multicentre, open-label, parallel-group, randomised, phase 3 trial was conducted at 34 medical research centres and hospitals in Japan. Eligible participants were aged 20 years or older with inadequately controlled (HbA1c ≥7·0% to |
| 5. |
Norifusa Iwahashi, Hironobu Umakoshi, Tsugio Seki, Celso E Gomez-Sanchez, Kuniaki Mukai, Makoto Suematsu, Yuta Umezawa, Mototsugu Oya, Takeo Kosaka, Masahide Seki, Yutaka Suzuki, Yutaka Horiuchi, Yoshihiro Ogawa, Koshiro Nishimoto, Characterization of Aldosterone-producing Cell Cluster (APCC) at Single-cell Resolution., The Journal of clinical endocrinology and metabolism, 10.1210/clinem/dgac394, 107, 9, 2439-2448, 2022.08, CONTEXT: The adrenal cortex consists of zona glomerulosa (ZG), fasciculata (ZF), and reticularis. Aldosterone-producing cell clusters that strongly express aldosterone synthase (CYP11B2) are frequently found in adult adrenals and harbor somatic mutations that are also detected in aldosterone-producing adenomas (APAs). Primary aldosteronism is mainly caused by APAs or idiopathic hyperaldosteronism (IHA). We presume that APCCs are causing IHA and are precursors of APAs. However, the gene expression characteristics and especially the development of APCC are not well understood. OBJECTIVE: This study aimed to analyze the transcriptome of APCC at single-cell resolution and infer the developmental trajectory. METHODS: Single-cell RNA sequencing (scRNA-seq) of two adult adrenals was performed. RESULTS: Immunohistochemical analyses confirmed the two adrenals had APCCs. scRNA-seq data of 2,928 adrenal cells were obtained and 1,765 adrenocortical cells were identified based on unsupervised clustering and the marker gene expression. The adrenocortical cells were divided into 6 clusters, of which three clusters (923 cells) were composed of APCC/ZG cells. By further sub-clustering, the APCC/ZG cells were divided into three clusters (clusters C1, C2, and C3), we finally identified APCC-cluster (C3) and ZG-cluster (C1). Cluster C2 seemed to be ZG-to-ZF transitional cells. RNA velocity analysis inferred the developmental direction from cluster ZG-cluster-C1 to APCC-cluster-C3. The scRNA-seq additionally revealed that many CYP11B2-positive cells were positive for CYP11B1 and/or CYP17A1, which were essential for cortisol but not for aldosterone production. CONCLUSIONS: Our results revealed the gene expression characteristics of APCC at single-cell resolution and show that some ZG cells remodel to APCC.. |
| 6. |
Seiichi Yano, Takashi Ishiuchi, Shusaku Abe, Satoshi H Namekawa, Gang Huang, Yoshihiro Ogawa, Hiroyuki Sasaki, Histone H3K36me2 and H3K36me3 form a chromatin platform essential for DNMT3A-dependent DNA methylation in mouse oocytes., Nature communications, 10.1038/s41467-022-32141-2, 13, 1, 4440-4440, 2022.08, Establishment of the DNA methylation landscape of mammalian oocytes, mediated by the DNMT3A-DNMT3L complex, is crucial for reproduction and development. In mouse oocytes, high levels of DNA methylation occur exclusively in the transcriptionally active regions, with moderate to low levels of methylation in other regions. Histone H3K36me3 mediates the high levels of methylation in the transcribed regions; however, it is unknown which histone mark guides the methylation in the other regions. Here, we show that, in mouse oocytes, H3K36me2 is highly enriched in the X chromosome and is broadly distributed across all autosomes. Upon H3K36me2 depletion, DNA methylation in moderately methylated regions is selectively affected, and a methylation pattern unique to the X chromosome is switched to an autosome-like pattern. Furthermore, we find that simultaneous depletion of H3K36me2 and H3K36me3 results in global hypomethylation, comparable to that of DNMT3A depletion. Therefore, the two histone marks jointly provide the chromatin platform essential for guiding DNMT3A-dependent DNA methylation in mouse oocytes.. |
| 7. |
Toru Masuda, Shojiro Haji, Yasuhiro Nakashima, Mariko Tsuda, Daisaku Kimura, Akiko Takamatsu, Norifusa Iwahashi, Hironobu Umakoshi, Motoaki Shiratsuchi, Chie Kikutake, Mikita Suyama, Yasuyuki Ohkawa, Yoshihiro Ogawa, Identification of a drug-response gene in multiple myeloma through longitudinal single-cell transcriptome sequencing., iScience, 10.1016/j.isci.2022.104781, 25, 8, 104781-104781, 2022.08, Despite recent therapeutic advances for multiple myeloma (MM), relapse is very common. Here, we conducted longitudinal single-cell transcriptome sequencing (scRNA-seq) of MM cells from a patient with relapsed MM, treated with multiple anti-myeloma drugs. We observed five subclusters of MM cells, which appeared and/or disappeared in response to the therapeutic pressure, and identified cluster 3 which emerged during lenalidomide treatment and disappeared after proteasome inhibitor (PI) treatment. Among the differentially expressed genes in cluster 3, we found a candidate drug-response gene; pellino E3 ubiquitin-protein ligase family member 2 (PELI2), which is responsible for PI-induced cell death in in vitro assay. Kaplan-Meier survival analysis of database revealed that higher expression of PELI2 is associated with a better prognosis. Our integrated strategy combining longitudinal scRNA-seq analysis, in vitro functional assay, and database analysis would facilitate the understanding of clonal dynamics of MM in response to anti-myeloma drugs and identification of drug-response genes.. |
| 8. |
Kiyoshi Yoshioka, Hiroshi Nagahisa, Fumihito Miura, Hiromitsu Araki, Yasutomi Kamei, Yasuo Kitajima, Daiki Seko, Jumpei Nogami, Yoshifumi Tsuchiya, Narihiro Okazaki, Akihiko Yonekura, Seigo Ohba, Yoshinori Sumita, Ko Chiba, Kosei Ito, Izumi Asahina, Yoshihiro Ogawa, Takashi Ito, Yasuyuki Ohkawa, Yusuke Ono, Hoxa10 mediates positional memory to govern stem cell function in adult skeletal muscle, Science Advances, 10.1126/sciadv.abd7924, 7, 24, eabd7924-eabd7924, 2021.06. |
| 9. |
Kiyoshi Yoshioka, Hiroshi Nagahisa, Fumihito Miura, Hiromitsu Araki, Yasutomi Kamei, Yasuo Kitajima, Daiki Seko, Jumpei Nogami, Yoshifumi Tsuchiya, Narihiro Okazaki, Akihiko Yonekura, Seigo Ohba, Yoshinori Sumita, Ko Chiba, Kosei Ito, Izumi Asahina, Yoshihiro Ogawa, Takashi Ito, Yasuyuki Ohkawa, Yusuke Ono, Hoxa10 mediates positional memory to govern stem cell function in adult skeletal muscle., Science advances, 10.1126/sciadv.abd7924, 7, 24, 2021.06, Muscle stem cells (satellite cells) are distributed throughout the body and have heterogeneous properties among muscles. However, functional topographical genes in satellite cells of adult muscle remain unidentified. Here, we show that expression of Homeobox-A (Hox-A) cluster genes accompanied with DNA hypermethylation of the Hox-A locus was robustly maintained in both somite-derived muscles and their associated satellite cells in adult mice, which recapitulates their embryonic origin. Somite-derived satellite cells were clearly separated from cells derived from cranial mesoderm in Hoxa10 expression. Hoxa10 inactivation led to genomic instability and mitotic catastrophe in somite-derived satellite cells in mice and human. Satellite cell-specific Hoxa10 ablation in mice resulted in a decline in the regenerative ability of somite-derived muscles, which were unobserved in cranial mesoderm-derived muscles. Thus, our results show that Hox gene expression profiles instill the embryonic history in satellite cells as positional memory, potentially modulating region-specific pathophysiology in adult muscles.. |
| 10. |
Yukina Takeichi, Takashi Miyazawa, Shohei Sakamoto, Yuki Hanada, Lixiang Wang, Kazuhito Gotoh, Keiichiro Uchida, Shunsuke Katsuhara, Ryuichi Sakamoto, Takaya Ishihara, Keiji Masuda, Naotada Ishihara, Masatoshi Nomura, Yoshihiro Ogawa, Non-alcoholic fatty liver disease in mice with hepatocyte-specific deletion of mitochondrial fission factor., Diabetologia, 10.1007/s00125-021-05488-2, 2021.05. |
| 11. |
Tatsuya Fukuda, Ryotaro Bouchi, Takato Takeuchi, Kikuko Amo-Shiinoki, Atsushi Kudo, Shinji Tanaka, Minoru Tanabe, Takumi Akashi, Kazuhiro Hirayama, Toshitaka Odamaki, Miki Igarashi, Ikuo Kimura, Katsuya Tanabe, Yukio Tanizawa, Tetsuya Yamada, Yoshihiro Ogawa, Importance of Intestinal Environment and Cellular Plasticity of Islets in the Development of Postpancreatectomy Diabetes., Diabetes care, 10.2337/dc20-0864, 44, 4, 1002-1011, 2021.04, OBJECTIVE: To elucidate the pathogenesis of postpancreatectomy diabetes mellitus (PPDM). RESEARCH DESIGN AND METHODS: Forty-eight patients without diabetes undergoing either pancreatoduodenectomy (PD) (n = 20) or distal pancreatectomy (DP) (n = 28) were included. A 75-g oral glucose tolerance test was performed every 6 months. Microbiome composition and short-chain fatty acids (SCFAs) in feces were examined before and 6 months after surgery. The association of histological characteristics of the resected pancreas with PPDM was examined. RESULTS: During follow-up (median 3.19 years), 2 of 20 PD patients and 16 of 28 DP patients developed PPDM. Proteobacteria relative abundance, plasma glucagon-like peptide 1 (GLP-1), and fecal butyrate levels increased only after PD. Postsurgical butyrate levels were correlated with postsurgical GLP-1 levels. With no significant difference in the volume of the resected pancreas between the surgical procedures, both β-cell and α-cell areas in the resected pancreas were significantly higher in DP patients than in PD patients. In DP patients, the progressors to diabetes showed preexisting insulin resistance compared with nonprogressors, and both increased α- and β-cell areas were predictors of PPDM. Furthermore, in DP patients, α-cell and β-cell areas were associated with ALDH1A3 expression in islets. CONCLUSIONS: We postulate that a greater removal of β-cells contributes to the development of PPDM after DP. Islet expansion along with preexisting insulin resistance is associated with high cellular plasticity, which may predict the development of PPDM after DP. In contrast, PD is associated with alterations of gut microbiome and increases in SCFA production and GLP-1 secretion, possibly protecting against PPDM development.. |
| 12. |
Ryotaro Bouchi, Noriyuki Sonoda, Jun Itoh, Yasuhiro Ono, Tatsuya Fukuda, Takato Takeuchi, Junji Kishimoto, Tetsuya Yamada, Yoshihiro Ogawa, Effects of intensive exercise combined with dapagliflozin on body composition in patients with type 2 diabetes: a randomized controlled trial., Endocrine journal, 10.1507/endocrj.EJ20-0599, 68, 3, 329-343, 2021.03, This study was aimed to evaluate the effects of intensive exercise in addition to the administration of sodium-glucose cotransporter 2 inhibitor dapagliflozin (DAPA) on body composition, including fat-free mass, in type 2 diabetes. We randomly assigned 146 patients to 24 weeks of treatment with intensive exercise, including resistance training, plus 5 mg (up to 10 mg) of DAPA daily (IT group) or DAPA alone (CT group). The primary endpoint was the difference in the change in fat-free mass from baseline to 24 weeks between the groups. The skeletal muscle mass index (SMI); metabolic profile, including HbA1c; and regional fat mass were also determined. ANCOVA was used for the group comparison, with least squares mean (LSM) differences and 95% confidence interval (CI). There was no significant difference in the change in fat-free mass (LSM difference -0.1 kg (95% CI: -0.5 to 0.4) and SMI (LSM difference -0.1 kg (95% CI: -0.2 to 0.1) between the groups. In contrast, the reduction of trunk fat mass was significantly higher in the IT group than in the CT group ((LSM difference -0.5 kg [95% CI -0.9 to -0.1]). Higher adherence to the resistance training tended to be associated with changes in HbA1c and high-sensitivity CRP levels. Our study suggests that intensive exercise do not prevent the reduction of fat-free mass after administration of SGLT2 inhibitors but can increase the reduction in abdominal fat, presumably leading to further improvements of hyperglycemia and chronic inflammation than DAPA alone in type 2 diabetes patients.. |
| 13. |
Kikuko Amo-Shiinoki, Katsuya Tanabe, Yoshinobu Hoshii, Hiroto Matsui, Risa Harano, Tatsuya Fukuda, Takato Takeuchi, Ryotaro Bouchi, Tokiyo Takagi, Masayuki Hatanaka, Komei Takeda, Shigeru Okuya, Wataru Nishimura, Atsushi Kudo, Shinji Tanaka, Minoru Tanabe, Takumi Akashi, Tetsuya Yamada, Yoshihiro Ogawa, Eiji Ikeda, Hiroaki Nagano, Yukio Tanizawa, Islet cell dedifferentiation is a pathologic mechanism of long-standing progression of type 2 diabetes., JCI insight, 10.1172/jci.insight.143791, 6, 1, 2021.01, Dedifferentiation has been implicated in β cell dysfunction and loss in rodent diabetes. However, the pathophysiological significance in humans remains unclear. To elucidate this, we analyzed surgically resected pancreatic tissues of 26 Japanese subjects with diabetes and 11 nondiabetic subjects, who had been overweight during adulthood but had no family history of diabetes. The diabetic subjects were subclassified into 3 disease stage categories, early, advanced, and intermediate. Despite no numerical changes in endocrine cells immunoreactive for chromogranin A (ChgA), diabetic islets showed profound β cell loss, with an increase in α cells without an increase in insulin and glucagon double-positive cells. The proportion of dedifferentiated cells that retain ChgA immunoreactivity without 4 major islet hormones was strikingly increased in diabetic islets and rose substantially during disease progression. The increased dedifferentiated cell ratio was inversely correlated with declining C-peptide index. Moreover, a subset of islet cells converted into exocrine-like cells during disease progression. These results indicate that islet remodeling with dedifferentiation is the underlying cause of β cell failure during the course of diabetes progression in humans.. |
| 14. |
Miyako Tanaka, Marie Saka-Tanaka, Kozue Ochi, Kumiko Fujieda, Yuki Sugiura, Tomofumi Miyamoto, Hiro Kohda, Ayaka Ito, Taiki Miyazawa, Akira Matsumoto, Seiichiro Aoe, Yoshihiro Miyamoto, Naotake Tsuboi, Shoichi Maruyama, Makoto Suematsu, Sho Yamasaki, Yoshihiro Ogawa, Takayoshi Suganami, C-type lectin Mincle mediates cell death-triggered inflammation in acute kidney injury., The Journal of experimental medicine, 10.1084/jem.20192230, 217, 11, 2020.11, Accumulating evidence indicates that cell death triggers sterile inflammation and that impaired clearance of dead cells causes nonresolving inflammation; however, the underlying mechanisms are still unclear. Here, we show that macrophage-inducible C-type lectin (Mincle) senses renal tubular cell death to induce sustained inflammation after acute kidney injury in mice. Mincle-deficient mice were protected against tissue damage and subsequent atrophy of the kidney after ischemia-reperfusion injury. Using lipophilic extract from the injured kidney, we identified β-glucosylceramide as an endogenous Mincle ligand. Notably, free cholesterol markedly enhanced the agonistic effect of β-glucosylceramide on Mincle. Moreover, β-glucosylceramide and free cholesterol accumulated in dead renal tubules in proximity to Mincle-expressing macrophages, where Mincle was supposed to inhibit clearance of dead cells and increase proinflammatory cytokine production. This study demonstrates that β-glucosylceramide in combination with free cholesterol acts on Mincle as an endogenous ligand to induce cell death-triggered, sustained inflammation after acute kidney injury.. |
| 15. |
Yuki Hanada, Naotada Ishihara, Lixiang Wang, Hidenori Otera, Takaya Ishihara, Takumi Koshiba, Katsuyoshi Mihara, Yoshihiro Ogawa, Masatoshi Nomura, MAVS is energized by Mff which senses mitochondrial metabolism via AMPK for acute antiviral immunity., Nature communications, 10.1038/s41467-020-19287-7, 11, 1, 5711-5711, 2020.11, Mitochondria are multifunctional organelles that produce energy and are critical for various signaling pathways. Mitochondrial antiviral signaling (MAVS) is a mitochondrial outer membrane protein essential for the anti-RNA viral immune response, which is regulated by mitochondrial dynamics and energetics; however, the molecular link between mitochondrial metabolism and immunity is unclear. Here we show in cultured mammalian cells that MAVS is activated by mitochondrial fission factor (Mff), which senses mitochondrial energy status. Mff mediates the formation of active MAVS clusters on mitochondria, independent of mitochondrial fission and dynamin-related protein 1. Under mitochondrial dysfunction, Mff is phosphorylated by the cellular energy sensor AMP-activated protein kinase (AMPK), leading to the disorganization of MAVS clusters and repression of the acute antiviral response. Mff also contributes to immune tolerance during chronic infection by disrupting the mitochondrial MAVS clusters. Taken together, Mff has a critical function in MAVS-mediated innate immunity, by sensing mitochondrial energy metabolism via AMPK signaling.. |
| 16. |
Hiroki Inada, Miyako Udono, Kanae Matsuda-Ito, Kenichi Horisawa, Yasuyuki Ohkawa, Shizuka Miura, Takeshi Goya, Junpei Yamamoto, Masao Nagasaki, Kazuko Ueno, Daisuke Saitou, Mikita Suyama, Yoshihiko Maehara, Wataru Kumamaru, Yoshihiro Ogawa, Sayaka Sekiya, Atsushi Suzuki, Direct reprogramming of human umbilical vein- and peripheral blood-derived endothelial cells into hepatic progenitor cells., Nature communications, 10.1038/s41467-020-19041-z, 11, 1, 5292-5292, 2020.10, Recent advances have enabled the direct induction of human tissue-specific stem and progenitor cells from differentiated somatic cells. However, it is not known whether human hepatic progenitor cells (hHepPCs) can be generated from other cell types by direct lineage reprogramming with defined transcription factors. Here, we show that a set of three transcription factors, FOXA3, HNF1A, and HNF6, can induce human umbilical vein endothelial cells to directly acquire the properties of hHepPCs. These induced hHepPCs (hiHepPCs) propagate in long-term monolayer culture and differentiate into functional hepatocytes and cholangiocytes by forming cell aggregates and cystic epithelial spheroids, respectively, under three-dimensional culture conditions. After transplantation, hiHepPC-derived hepatocytes and cholangiocytes reconstitute damaged liver tissues and support hepatic function. The defined transcription factors also induce hiHepPCs from endothelial cells circulating in adult human peripheral blood. These expandable and bipotential hiHepPCs may be useful in the study and treatment of human liver diseases.. |
| 17. |
, Yuko Akehi, Toshihiko Yanase, Ryoko Motonaga, Hironobu Umakoshi, Mika Tsuiki, Yoshiyu Takeda, Takashi Yoneda, Isao Kurihara, Hiroshi Itoh, Takuyuki Katabami, Takamasa Ichijo, Norio Wada, Yui Shibayama, Takanobu Yoshimoto, Kenji Ashida, Yoshihiro Ogawa, Junji Kawashima, Masakatsu Sone, Nobuya Inagaki, Katsutoshi Takahashi, Megumi Fujita, Minemori Watanabe, Yuichi Matsuda, Hiroki Kobayashi, Hirotaka Shibata, Kohei Kamemura, Michio Otsuki, Yuichi Fujii, Koichi Yamamoto, Atsushi Ogo, Shintaro Okamura, Shozo Miyauchi, Tomikazu Fukuoka, Shoichiro Izawa, Shigeatsu Hashimoto, Masanobu Yamada, Yuichiro Yoshikawa, Tatsuya Kai, Tomoko Suzuki, Takashi Kawamura, Mitsuhide Naruse, High prevalence of diabetes in patients with primary aldosteronism (PA) associated with subclinical hypercortisolism and prediabetes more prevalent in bilateral than unilateral PA
A large, multicenter cohort study in Japan, Diabetes care, 10.2337/dc18-1293, 42, 5, 938-945, 2019.05, OBJECTIVE To investigate the prevalence and causes of diabetes in patients with primary aldosteronism (PA) in a multi-institutional cohort study in Japan. RESEARCH DESIGN AND METHODS The prevalence of diabetes was determined in 2,210 patients with PA (diagnosed or glycated hemoglobin [HbA1c] ‡6.5% [‡48 mmol/mol]; NGSP) and compared with that of the Japanese general population according to age and sex. In 1,386 patients with PA and clear laterality (unilateral or bilateral), the effects of plasma aldosterone concentration (PAC), hypokalemia (1c 1c 2 test revealed a significant contribution of suspected SH to diabetes. Despite more active PA profiles (e.g., higher PAC and lower potassium concentrations) in unilateral than bilateral PA, BMI and HbA1c values were significantly higher in bilateral PA. PA laterality had no effect on the prevalence of diabetes; however, the prevalence of prediabetes was significantly higher in bilateral than unilateral PA. CONCLUSIONS Individuals with PA have a high prevalence of diabetes, which is associated mainly with SH. The prevalence of prediabetes is greater for bilateral than unilateral PA, suggesting a unique metabolic cause of bilateral PA.. |
| 18. |
Xunmei Yuan, Kazutaka Tsujimoto, Koshi Hashimoto, Kenichi Kawahori, Nozomi Hanzawa, Miho Hamaguchi, Takami Seki, Makiko Nawa, Tatsuya Ehara, Yohei Kitamura, Izuho Hatada, Morichika Konishi, Nobuyuki Itoh, Yoshimi Nakagawa, Hitoshi Shimano, Takako Takai-Igarashi, Yasutomi Kamei, Yoshihiro Ogawa, Epigenetic modulation of Fgf21 in the perinatal mouse liver ameliorates diet-induced obesity in adulthood, Nature communications, 10.1038/s41467-018-03038-w, 9, 1, 2018.12, The nutritional environment to which animals are exposed in early life can lead to epigenetic changes in the genome that influence the risk of obesity in later life. Here, we demonstrate that the fibroblast growth factor-21 gene (Fgf21) is subject to peroxisome proliferator-activated receptor (PPAR) α-dependent DNA demethylation in the liver during the postnatal period. Reductions in Fgf21 methylation can be enhanced via pharmacologic activation of PPARα during the suckling period. We also reveal that the DNA methylation status of Fgf21, once established in early life, is relatively stable and persists into adulthood. Reduced DNA methylation is associated with enhanced induction of hepatic FGF21 expression after PPARα activation, which may partly explain the attenuation of diet-induced obesity in adulthood. We propose that Fgf21 methylation represents a form of epigenetic memory that persists into adulthood, and it may have a role in the developmental programming of obesity.. |
| 19. |
K. Kawahori, K. Hashimoto, X. Yuan, K. Tsujimoto, N. Hanzawa, M. Hamaguchi, S. Kase, K. Fujita, K. Tagawa, H. Okazawa, Y. Nakajima, N. Shibusawa, M. Yamada, and Y. Ogawa. , Mild maternal hypothyroxinemia during pregnancy induces persistent DNA hypermethylation in the hippocampal brain-derived neurotrophic factor gene in mouse offspring. , Thyroid, 10.1089/thy.2017.0331., 28, 3, 395-406, 2018.03. |
| 20. |
X. Yuan, K. Tsujimoto, K. Hashimoto, K. Kawahori, N. Hanzawa, M. Hamaguchi, T. Seki, M. Nawa, T. Ehara, Y. Kitamura, I. Hatada, M. Konishi, N. Itoh, Y. Nakagawa, H. Shimano, T. Takai-Igarashi, Y. Kamei, and Y. Ogawa., Epigenetic modulation of Fgf21 in the perinatal mouse liver ameliorates diet-induced obesity in adulthood., Nat. Commun., 10.1038/s41467-018-03038-w., 9, e636, 2018.02. |
| 21. |
K. Shiba, K. Tsuchiya, C. Komiya, Y. Miyachi, K. Mori, N. Shimazu, S. Yamaguchi, N. Ogasawara, M. Katoh, M. Itoh, T. Suganami, and Y. Ogawa., Canagliflozin, an SGLT2 inhibitor, attenuates the development of hepatocellular carcinoma in a mouse model of human NASH. , Sci. Rep. , 8, e2362, 2018.01. |
| 22. |
K. Hashimoto, E. Nishihara, M. Matsumoto, S. Matsumoto, Y. Nakajima, K. Tsujimoto, H. Yamakage, N. Asahara-Satoh, J. Noh, K. Ito, A. Miyauchi, M. Mori, M. Yamada, and Y. Ogawa., Sialic acid-binding immunoglobulin-like lectin1 as a novel predictive biomarker for relapse in Graves’ disease: a multicenter study., Thyroid, 10.1089/thy, 28, 1, 50-59, 2018.01. |
| 23. |
Kohjiro Ueki, Takayoshi Sasako, Yukiko Okazaki, Masayuki Kato, Sumie Okahata, Hisayuki Katsuyama, Mikiko Haraguchi, Ai Morita, Ken Ohashi, Kazuo Hara, Atsushi Morise, Kazuo Izumi, Naoki Ishizuka, Yasuo Ohashi, Mitsuhiko Noda, Takashi Kadowaki, Masakazu Haneda, Yasunori Iwashima, Toshihiro Suda, Naoki Tamasawa, Makoto Daimon, Jo Satoh, Noriko Takebe, Yasushi Ishigaki, Tsuyoshi Watanabe, Hiroaki Satoh, Kikuo Kasai, Yoshimasa Aso, Shun Ishibashi, Shigehiro Katayama, San e. Ishikawa, Masafumi Kakei, Kazuyuki Namai, Naotake Hashimoto, Yoshifumi Suzuki, Shunichiro Onishi, Koutaro Yokote, Masafumi Matsuda, Masahiro Masuzawa, Yoichi Hayashi, Satoshi Saito, Norikazu Ogihara, Hisamitsu Ishihara, Naoko Tajima, Kazunori Utsunomiya, Akira Shimada, Hiroshi Itoh, Ryuzo Kawamori, Hirotaka Watada, Michio Hayashi, Yasumichi Mori, Teruo Shiba, Akihiro Isogawa, Hiroshi Sakura, Masato Odawara, Kazuyuki Tobe, Kazuhisa Tsukamoto, Toshimasa Yamauchi, Tamio Teramoto, Yukio Hirata, Isao Uchimura, Yoshihiro Ogawa, Gen Yoshino, Takahisa Hirose, Hiroshi Kajio, Yoshihito Atsumi, Akira Shimada, Yoichi Oikawa, Atsushi Araki, Akio Ueki, Atsushi Ohno, Masafumi Kitaoka, Yoshikuni Fujita, Tatsumi Moriya, Taiki Tojo, Masayoshi Shichiri, Daisuke Suzuki, Masao Toyoda, Kumiko Hamano, Rieko Komi, Yasuo Terauchi, Nobuaki Kuzuya, Masayo Yamada, Toshinari Takamura, Mitsuo Imura, Hiroshi Tanaka, Masayuki Hayashi, Yasuhisa Kato, Mitsuyasu Itoh, Atsushi Suzuki, Mikihiro Nakayama, Takahisa Sano, Eitaro Nakashima, Yasuhiro Sumida, Yutaka Yano, Tsuyoshi Tanaka, Kazuya Murata, Atsunori Kashiwagi, Hiroshi Maegawa, Shigeo Kono, Nobuya Inagaki, Keisuke Kosugi, Tetsuyuki Yasuda, Yasunao Yoshimasa, Ichiro Kishimoto, Toshihiko Sato, Masayuki Hosoi, Tomoyuki Yamasaki, Munehide Matsuhisa, Iichiro Shimomura, Ataru Taniguchi, Akira Kuroe, Takeshi Kurose, Takeshi Ohara, Kazuhiko Sakaguchi, Mitsuyoshi Namba, Kohei Kaku, Masazumi Fujiwara, Ikki Shimizu, Keizo Ono, Osamu Ebisui, Yukio Tanizawa, Yosuke Okada, Shoichi Natori, Takehiko Kodera, Naoichi Sato, Makoto Ide, Kentaro Yamada, Fumio Umeda, Shoichi Natori, Tomoaki Eto, Kazuo Mimura, Shinsuke Hiramatsu, Tomoaki Inoue, Ryoko Takei, Atsushi Ogo, Katsumi Eguchi, Eiji Kawasaki, Yuji Koide, Eiichi Araki, Hideaki Jinnouchi, Hiroaki Yamamoto, Mitsutaka Motoyoshi, Toru Hiyoshi, Yasushi Tanaka, Tadahisa Momoki, Koichiro Sato, Akihiko Yoneyama, Kenichi Ito, Hiroshi Sobajima, Hiroshi Ikegami, Masaki Ikeda, Hiroki Ikeda, Kenji Takahashi, Hirofumi Makino, Yasuo Ueda, Masamitsu Nakazato, Effect of an intensified multifactorial intervention on cardiovascular outcomes and mortality in type 2 diabetes (J-DOIT3)
an open-label, randomised controlled trial, The Lancet Diabetes and Endocrinology, 10.1016/S2213-8587(17)30327-3, 5, 12, 951-964, 2017.12, Background Limited evidence suggests that multifactorial interventions for control of glucose, blood pressure, and lipids reduce macrovascular complications and mortality in patients with type 2 diabetes. However, safe and effective treatment targets for these risk factors have not been determined for such interventions. Methods In this multicentre, open-label, randomised, parallel-group trial, undertaken at 81 clinical sites in Japan, we randomly assigned (1:1) patients with type 2 diabetes aged 45–69 years with hypertension, dyslipidaemia, or both, and an HbA1c of 6·9% (52·0 mmol/mol) or higher, to receive conventional therapy for glucose, blood pressure, and lipid control (targets: HbA1c 1c 1c, and history of cardiovascular disease. Neither patients nor investigators were masked to group assignment. The primary outcome was occurrence of any of a composite of myocardial infarction, stroke, revascularisation (coronary artery bypass surgery, percutaneous transluminal coronary angioplasty, carotid endarterectomy, percutaneous transluminal cerebral angioplasty, and carotid artery stenting), and all-cause mortality. The primary analysis was done in the intention-to-treat population. This study is registered with ClinicalTrials.gov, number NCT00300976. Findings Between June 16, 2006, and March 31, 2009, 2542 eligible patients were randomly assigned to intensive therapy or conventional therapy (1271 in each group) and followed up for a median of 8·5 years (IQR 7·3–9·0). Two patients in the intensive therapy group were found to be ineligible after randomisation and were excluded from the analyses. During the intervention period, mean HbA1c, systolic blood pressure, diastolic blood pressure, and LDL cholesterol concentrations were significantly lower in the intensive therapy group than in the conventional therapy group (6·8% [51·0 mmol/mol] vs 7·2% [55·2 mmol/mol]; 123 mm Hg vs 129 mm Hg; 71 mm Hg vs 74 mm Hg; and 85 mg/dL vs 104 mg/dL, respectively; all p |
| 24. |
Michiko Itoh, Takayoshi Suganami, Hideaki Kato, Sayaka Kanai, Ibuki Shirakawa, Takeru Sakai, Toshihiro Goto, Masahiro Asakawa, Isao Hidaka, Hiroshi Sakugawa, Koji Ohnishi, Yoshihiro Komohara, Kenichi Asano, Isao Sakaida, Masato Tanaka, Yoshihiro Ogawa, CD11c+ resident macrophages drive hepatocyte death-triggered liver fibrosis in a murine model of nonalcoholic steatohepatitis, JCI Insight, 10.1172/jci.insight.92902, 2, 22, 2017.11, Although recent evidence has pointed to the role of organ- and pathogenesis-specific macrophage subsets, it is still unclear which subsets are critically involved in the pathogenesis of nonalcoholic steatohepatitis (NASH). Using melanocortin-4 receptor-deficient (MC4R-KO) mice fed Western diet (WD), which exhibit liver phenotypes similar to those of human NASH, we found a histological structure, termed hepatic crown-like structure (hCLS), in which CD11c+ macrophages surround dead/dying hepatocytes, a prominent feature of NASH. Here, we demonstrate that hCLS-constituting macrophages could be a novel macrophage subset that drives hepatocyte death-triggered liver fibrosis. In an "inducible NASH model," hepatocyte death induces hCLS formation and liver fibrosis sequentially in the short term. In combination with the long-term WD feeding model, we also showed that resident macrophages are a major cellular source of CD11c+ macrophages constituting hCLS, which exhibited gene expression profiles distinct from CD11c- macrophages scattered in the liver. Moreover, depletion of CD11c+ macrophages abolished hCLS formation and fibrogenesis in NASH. Our clinical data suggest the role of CD11c+ macrophages in the disease progression from simple steatosis to NASH. This study sheds light on the role of resident macrophages, in addition to recruited macrophages, in the pathogenesis of NASH.. |
| 25. |
Akira Matsumoto, Miyako Tanaka, Hiroko Matsumoto, Kozue Ochi, Yuki Moro-Oka, Hirohito Kuwata, Hironori Yamada, Ibuki Shirakawa, Taiki Miyazawa, Hitoshi Ishii, Kazunori Kataoka, Yoshihiro Ogawa, Yuji Miyahara, Takayoshi Suganami, Synthetic "smart gel" provides glucose-responsive insulin delivery in diabetic mice, Science Advances, 10.1126/sciadv.aaq0723, 3, 11, 2017.11, Although previous studies have attempted to create "electronics-free" insulin delivery systemsusing glucose oxidase and sugar-binding lectins as a glucose-sensingmechanism, no successful clinical translation has hitherto beenmade. These protein-based materials are intolerant of long-term use and storage because of their denaturing and/or cytotoxic properties. We provide a solution by designing a protein-free and totally synthetic material-based approach. Capitalizing on the sugar-responsive properties of boronic acid, we have established a synthetic polymer gel-based insulin delivery device confined within a single catheter, which exhibits an artificial pancreas-like function in vivo. Subcutaneous implantation of the device in healthy and diabetic mice establishes a closed-loop systemcomposed of "continuous glucose sensing" and "skin layer"-regulated insulin release. As a result, glucose metabolism was controlled in response to interstitial glucose fluctuation under both insulin-deficient and insulin-resistant conditions with at least 3-week durability. Our "smart gel" technology could offer a user-friendly and remarkably economic (disposable) alternative to the current state of the art, thereby facilitating availability of effective insulin treatment not only to diabetic patients in developing countries but also to those patients who otherwise may not be strongly motivated, such as the elderly, infants, and patients in need of nursing care.. |
| 26. |
Eulalia A. Coutinho, Shiki Okamoto, Ayako Wendy Ishikawa, Shigefumi Yokota, Nobuhiro Wada, Takahiro Hirabayashi, Kumiko Saito, Tatsuya Sato, Kazuyo Takagi, Chen Chi Wang, Kenta Kobayashi, Yoshihiro Ogawa, Seiji Shioda, Yumiko Yoshimura, Yasuhiko Minokoshi, Activation of SF1 neurons in the ventromedial hypothalamus by DREADD technology increases insulin sensitivity in peripheral tissues, Diabetes, 10.2337/db16-1344, 66, 9, 2372-2386, 2017.09, The ventromedial hypothalamus (VMH) regulates glucose and energy metabolism in mammals. Optogenetic stimulation of VMH neurons that express steroidogenic factor 1 (SF1) induces hyperglycemia. However, leptin acting via the VMH stimulates whole-body glucose utilization and insulin sensitivity in some peripheral tissues, and this effect of leptin appears to be mediated by SF1 neurons. We examined the effects of activation of SF1 neurons with DREADD (designer receptors exclusively activated by designer drugs) technology. Activation of SF1 neurons by an intraperitoneal injection of clozapine-N-oxide (CNO), a specific hM3Dq ligand, reduced food intake and increased energy expenditure in mice expressing hM3Dq in SF1 neurons. It also increased whole-body glucose utilization and glucose uptake in red-type skeletal muscle, heart, and interscapular brown adipose tissue, as well as glucose production and glycogen phosphorylase a activity in the liver, thereby maintaining blood glucose levels. During hyperinsulinemic-euglycemic clamp, such activation of SF1 neurons increased insulin-induced glucose uptake in the same peripheral tissues and tended to enhance insulin-induced suppression of glucose production by suppressing gluconeogenic gene expression and glycogen phosphorylase a activity in the liver. DREADD technology is thus an important tool for studies of the role of the brain in the regulation of insulin sensitivity in peripheral tissues.. |
| 27. |
Norio Miyamura, Shoji Hata, Tohru Itoh, Minoru Tanaka, Miki Nishio, Michiko Itoh, Yoshihiro Ogawa, Shuji Terai, Isao Sakaida, Akira Suzuki, Atsushi Miyajima, Hiroshi Nishina, YAP determines the cell fate of injured mouse hepatocytes in vivo, Nature communications, 10.1038/ncomms16017, 8, 2017.07, The presence of senescent, transformed or damaged cells can impair tissue function or lead to tumorigenesis; therefore, organisms have evolved quality control mechanisms to eliminate them. Here, we show that YAP activation induced by inactivation of the Hippo pathway specifically in damaged hepatocytes promotes their selective elimination by using in vivo mosaic analysis in mouse liver. These damaged hepatocytes migrate into the hepatic sinusoids, undergo apoptosis and are engulfed by Kupffer cells. In contrast, YAP activation in undamaged hepatocytes leads to proliferation. Cellular stresses such as ethanol that damage both liver sinusoidal endothelial cells and hepatocytes switch cell fate from proliferation to migration/apoptosis in the presence of activated YAP. This involves the activation of CDC42 and Rac that regulate cell migration. Thus, we suggest that YAP acts as a stress sensor that induces elimination of injured cells to maintain tissue and organ homeostasis.. |
| 28. |
Yasutaka Miyachi, Kyoichiro Tsuchiya, Chikara Komiya, Kumiko Shiba, Noriko Shimazu, Shinobu Yamaguchi, Michiyo Deushi, Mizuko Osaka, Kouji Inoue, Yuta Sato, Sayaka Matsumoto, Junichi Kikuta, Kenjiro Wake, Masayuki Yoshida, Masaru Ishii, Yoshihiro Ogawa, Roles for Cell-Cell Adhesion and Contact in Obesity-Induced Hepatic Myeloid Cell Accumulation and Glucose Intolerance, Cell Reports, 10.1016/j.celrep.2017.02.039, 18, 11, 2766-2779, 2017.03, Obesity promotes infiltration of inflammatory cells into various tissues, leading to parenchymal and stromal cell interaction and development of cellular and organ dysfunction. Liver sinusoidal endothelial cells (LSECs) are the first cells that contact portal blood cells and substances in the liver, but their functions in the development of obesity-associated glucose metabolism remain unclear. Here, we find that LSECs are involved in obesity-associated accumulation of myeloid cells via VLA-4-dependent cell-cell adhesion. VLA-4 blockade in mice fed a high-fat diet attenuated myeloid cell accumulation in the liver to improve hepatic inflammation and systemic glucose intolerance. Ex vivo studies further show that cell-cell contact between intrahepatic leukocytes and parenchymal hepatocytes induces gluconeogenesis via a Notch-dependent pathway. These findings suggest that cell-cell interaction between parenchymal and stromal cells regulates hepatic glucose metabolism and offers potential strategies for treatment or prevention of obesity-associated glucose intolerance.. |
| 29. |
Tatsuya Ehara, Yasutomi Kamei, Xunmei Yuan, Mayumi Takahashi, Sayaka Kanai, Erina Tamura, Kazutaka Tsujimoto, Takashi Tamiya, Yoshimi Nakagawa, Hitoshi Shimano, Takako Takai-Igarashi, Izuho Hatada, Takayoshi Suganami, Koshi Hashimoto, Yoshihiro Ogawa, Ligand-activated PPARα-dependent DNA demethylation regulates the fatty acid β-oxidation genes in the postnatal liver, Diabetes, 10.2337/db14-0158, 64, 3, 775-784, 2015.03, The metabolic function of the liver changes sequentially during early life in mammals to adapt to the marked changes in nutritional environment. Accordingly, hepatic fatty acid β-oxidation is activated after birth to produce energy from breast milk lipids. However, how it is induced during the neonatal period is poorly understood. Here we show DNA demethylation and increased mRNA expression of the fatty acid β-oxidation genes in the postnatal mouse liver. The DNA demethylation does not occur in the fetal mouse liver under the physiologic condition, suggesting that it is specific to the neonatal period. Analysis of mice deficient in the nuclear receptor peroxisome proliferator-activated receptor a (PPARα) and maternal administration of a PPARα ligand during the gestation and lactation periods reveal that the DNA demethylation is PPARα dependent. We also find that DNA methylation of the fatty acid β-oxidation genes are reduced in the adult human liver relative to the fetal liver. This study represents the first demonstration that the ligand-activated PPARα-dependent DNA demethylation regulates the hepatic fatty acid β-oxidation genes during the neonatal period, thereby highlighting the role of a lipid-sensing nuclear receptor in the gene- and lifestage- specific DNA demethylation of a particular metabolic pathway.. |
| 30. |
Masatoshi Takagi, Hatsume Uno, Rina Nishi, Masataka Sugimoto, Setsuko Hasegawa, Jinhua Piao, Norimasa Ihara, Sayaka Kanai, Saori Kakei, Yoshifumi Tamura, Takayoshi Suganami, Yasutomi Kamei, Toshiaki Shimizu, Akio Yasuda, Yoshihiro Ogawa, Shuki Mizutani, ATM Regulates Adipocyte Differentiation and Contributes to Glucose Homeostasis, Cell Reports, 10.1016/j.celrep.2015.01.027, 10, 6, 957-967, 2015.02, Ataxia-telangiectasia (A-T) patients occasionally develop diabetes mellitus. However, only limited attempts have been made to gain insight into the molecular mechanism of diabetes mellitus development in A-T patients. We found that Atm-/- mice were insulin resistant and possessed less subcutaneous adipose tissue as well as a lower level of serum adiponectin than Atm+/+ mice. Furthermore, invitro studies revealed impaired adipocyte differentiation in Atm-/- cells caused by the lack of induction of C/EBPα and PPARγ, crucial transcription factors involved in adipocyte differentiation. Interestingly, ATM was activated by stimuli that induced differentiation, and the binding of ATM to C/EBPβ and p300 was involved in the transcriptional regulation of C/EBPα and adipocyte differentiation. Thus, our study sheds light on the poorly understood role of ATM in the pathogenesis of glucose intolerance in A-T patients and providesinsight into the role of ATM in glucose metabolism.. |
| 31. |
Naoki Sawada, Aihua Jiang, Fumihiko Takizawa, Adeel Safdar, Andre Manika, Yevgenia Tesmenitsky, Kyu Tae Kang, Joyce Bischoff, Hermann Kalwa, Juliano L. Sartoretto, Yasutomi Kamei, Laura E. Benjamin, Hirotaka Watada, Yoshihiro Ogawa, Yasutomi Higashikuni, Chase W. Kessinger, Farouc A. Jaffer, Thomas Michel, Masataka Sata, Kevin Croce, Rica Tanaka, Zolt Arany, Endothelial PGC-1α mediates vascular dysfunction in diabetes, Cell metabolism, 10.1016/j.cmet.2013.12.014, 19, 2, 246-258, 2014.02, Endothelial dysfunction is a central hallmark of diabetes. The transcriptional coactivator PGC-1α is a powerful regulator of metabolism, but its role in endothelial cells remains poorly understood. We show here that endothelial PGC-1α expression is high in diabetic rodents and humans and that PGC-1α powerfully blocks endothelial migration in cell culture and vasculogenesis in vivo. Mechanistically, PGC-1α induces Notch signaling, blunts activation of Rac/Akt/eNOS signaling, and renders endothelial cells unresponsive to established angiogenic factors. Transgenic overexpression of PGC-1α in the endothelium mimics multiple diabetic phenotypes, including aberrant re-endothelialization after carotid injury, blunted wound healing, and reduced blood flow recovery after hindlimb ischemia. Conversely, deletion of endothelial PGC-1α rescues the blunted wound healing and recovery from hindlimb ischemia seen in type 1 and type 2 diabetes. Endothelial PGC-1α thus potently inhibits endothelial function and angiogenesis, and induction of endothelial PGC-1α contributes to multiple aspects of vascular dysfunction in diabetes.. |
| 32. |
Yorihiro Iwasaki, Takayoshi Suganami, Rumi Hachiya, Ibuki Shirakawa, Misa Kim-Saijo, Miyako Tanaka, Miho Hamaguchi, Takako Takai-Igarashi, Michikazu Nakai, Yoshihiro Miyamoto, Yoshihiro Ogawa, Activating transcription factor 4 links metabolic stress to interleukin-6 expression in macrophages, Diabetes, 10.2337/db13-0757, 63, 1, 152-161, 2014.01, Chronic inflammation is a molecular element of the metabolic syndrome and type 2 diabetes. Saturated fatty acids (SFAs) are considered to be an important proinflammatory factor. However, it is still incompletely understood how SFAs induce proinflammatory cytokine expression. Hereby we report that activating transcription factor (ATF) 4, a transcription factor that is induced downstream of metabolic stresses including endoplasmic reticulum (ER) stress, plays critical roles in SFA-induced interleukin-6 (Il6) expression. DNA microarray analysis using primary macrophages revealed that the ATF4 pathway is activated by SFAs. Haploinsufficiency and short hairpin RNA-based knockdown of ATF4 in macrophages markedly inhibited SFA- and metabolic stress-induced Il6 expression. Conversely, pharmacological activation of the ATF4 pathway and overexpression of ATF4 resulted in enhanced Il6 expression. Moreover, ATF4 acts in synergy with the Toll-like receptor-4 signaling pathway, which is known to be activated by SFAs. At a molecular level, we found that ATF4 exerts its proinflammatory effects through at least two different mechanisms: ATF4 is involved in SFAinduced nuclear factor-kB activation; and ATF4 directly activates the Il6 promoter. These findings provide evidence suggesting that ATF4 links metabolic stress and Il6 expression in macrophages.. |
| 33. |
Miyako Tanaka, Kenji Ikeda, Takayoshi Suganami, Chikara Komiya, Kozue Ochi, Ibuki Shirakawa, Miho Hamaguchi, Satoshi Nishimura, Ichiro Manabe, Takahisa Matsuda, Kumi Kimura, Hiroshi Inoue, Yutaka Inagaki, Seiichiro Aoe, Sho Yamasaki, Yoshihiro Ogawa, Macrophage-inducible C-type lectin underlies obesity-induced adipose tissue fibrosis, Nature communications, 10.1038/ncomms5982, 5, 2014.09, In obesity, a paracrine loop between adipocytes and macrophages augments chronic inflammation of adipose tissue, thereby inducing systemic insulin resistance and ectopic lipid accumulation. Obese adipose tissue contains a unique histological structure termed crown-like structure (CLS), where adipocyte-macrophage crosstalk is known to occur in close proximity. Here we show that Macrophage-inducible C-type lectin (Mincle), a pathogen sensor for Mycobacterium tuberculosis, is localized to macrophages in CLS, the number of which correlates with the extent of interstitial fibrosis. Mincle induces obesity-induced adipose tissue fibrosis, thereby leading to steatosis and insulin resistance in liver. We further show that Mincle in macrophages is crucial for CLS formation, expression of fibrosis-related genes and myofibroblast activation. This study indicates that Mincle, when activated by an endogenous ligand released from dying adipocytes, is involved in adipose tissue remodelling, thereby suggesting that sustained interactions between adipocytes and macrophages within CLS could be a therapeutic target for obesity-induced ectopic lipid accumulation.. |
| 34. |
Satomi Yogosawa, Shin Mizutani, Yoshihiro Ogawa, Tetsuro Izumi, Activin receptor-like kinase 7 suppresses lipolysis to accumulate fat in obesity through downregulation of peroxisome proliferator-activated receptor γ and C/EBPα, Diabetes, 10.2337/db12-0295, 62, 1, 115-123, 2013.01, We previously identified a quantitative trait locus for adiposity, non-insulin-dependent diabetes 5 (Nidd5), on mouse chromosome 2. In the current study, we identified the actual genetic alteration at Nidd5 as a nonsense mutation of the Acvr1c gene encoding activin receptor-like kinase 7 (ALK7), one of the type I transforming growth factor-β receptors, which results in a COOH-terminal deletion of the kinase domain. We further showed that the ALK7 dysfunction causes increased lipolysis in adipocytes and leads to decreased fat accumulation. Conversely, ALK7 activation inhibits lipolysis by suppressing the expression of adipose lipases. ALK7 and activated Smads repress those lipases by downregulating peroxisome proliferator-activated receptor γ ( PPAR γ) and CCAAT/enhancer binding protein (C/EBP) α. Although PPARγ and C/EBPα act as adipogenic transcription factors during adipocyte differentiation, they are lipolytic in sum in differentiated adipocytes and are downregulated by ALK7 in obesity to accumulate fat. Under the obese state, ALK7 deficiency improves glucose tolerance and insulin sensitivity by preferentially increasing fat combustion in mice. These findings have uncovered a net lipolytic function of PPARγ and C/EBPα in differentiated adipocytes and point to the ALK7-signaling pathway that is activated in obesity as a potential target of medical intervention.. |
| 35. |
Noriko Satoh-Asahara, Akira Shimatsu, Yousuke Sasaki, Hidenori Nakaoka, Akihiro Himeno, Mayu Tochiya, Shigeo Kono, Tomohide Takaya, Koh Ono, Hiromichi Wada, Takayoshi Suganami, Koji Hasegawa, Yoshihiro Ogawa, Highly purified eicosapentaenoic acid increases interleukin-10 levels of peripheral blood monocytes in obese patients with dyslipidemia, Diabetes care, 10.2337/dc12-0269, 35, 12, 2631-2639, 2012.12, OBJECTIVE - It has recently been highlighted that proinflammatory (M1) macrophages predominate over anti-inflammatory (M2) macrophages in obesity, thereby contributing to obesityinduced adipose inflammation and insulin resistance. A recent clinical trial revealed that highly purified eicosapentaenoic acid (EPA) reduces the incidence of major coronary events. In this study, we examined the effect of EPA on M1/M2-like phenotypes of peripheral blood monocytes in obese dyslipidemic patients. RESEARCH DESIGN AND METHODS - Peripheral bloodmonocyteswere prepared from 26 obese patients without and 90 obese patients with dyslipidemia. Of the latter 90 obese patients with dyslipidemia, 82 patientswere treated with orwithout EPA treatment (1.8 g daily) for 3months. RESULTS - Monocytes in obese patients with dyslipidemia showed a significantly lower expression of interleukin-10 (IL-10), an M2 marker, than those without dyslipidemia. EPA significantly increased serum IL-10 and EPA levels, the EPA/arachidonic acid (AA) ratio, andmonocyte IL-10 expression and decreased the pulse wave velocity (PWV), an index of arterial stiffness, compared with the control group. After EPA treatment, the serum EPA/AA ratio was significantly correlated with monocyte IL-10 expression. Only increases in monocyte IL-10 expression and serum adiponectin were independent determinants of a decreased PWV by EPA. Furthermore, EPA significantly increased the expression and secretion of IL-10 in human monocytic THP-1 cells through a peroxisome proliferator-activated receptor (PPAR)g-dependent pathway. CONCLUSIONS - This study is the first to show that EPA increases the monocyte IL-10 expression in parallel with decrease of arterial stiffness, which may contribute to the antiatherogenic effect of EPA in obese dyslipidemic patients.. |
| 36. |
Tatsuya Ehara, Yasutomi Kamei, Mayumi Takahashi, Xunmei Yuan, Sayaka Kanai, Erina Tamura, Miyako Tanaka, Tomomi Yamazaki, Shinji Miura, Osamu Ezaki, Takayoshi Suganami, Masaki Okano, Yoshihiro Ogawa, Role of DNA methylation in the regulation of lipogenic glycerol-3-phosphate acyltransferase 1 gene expression in the mouse neonatal liver, Diabetes, 10.2337/db11-1834, 61, 10, 2442-2450, 2012.10, The liver is a major organ of lipid metabolism, which is markedly changed in response to physiological nutritional demand; however, the regulation of hepatic lipogenic gene expression in early life is largely unknown. In this study, we show that expression of glycerol- 3-phosphate acyltransferase 1 (GPAT1; Gpam), a rate-limiting enzyme of triglyceride biosynthesis, is regulated in the mouse liver by DNA methylation, an epigenetic modification involved in the regulation of a diverse range of biological processes in mammals. In the neonatal liver, DNA methylation of the Gpam promoter, which is likely to be induced by Dnmt3b, inhibited recruitment of the lipogenic transcription factor sterol regulatory element-binding protein- 1c (SREBP-1c), whereas in the adult, decreased DNA methylation resulted in active chromatin conformation, allowing recruitment of SREBP-1c. Maternal overnutrition causes decreased Gpam promoter methylation with increased GPAT1 expression and triglyceride content in the pup liver, suggesting that environmental factors such as nutritional conditions can affect DNA methylation in the liver. This study is the first detailed analysis of the DNA-methylation-dependent regulation of the triglyceride biosynthesis gene Gpam, thereby providing new insight into the molecular mechanism underlying the epigenetic regulation of metabolic genes and thus metabolic diseases.. |
| 37. |
T. Kuwabara, K. Mori, M. Mukoyama, M. Kasahara, H. Yokoi, Y. Saito, Y. Ogawa, H. Imamaki, T. Kawanishi, A. Ishii, K. Koga, K. P. Mori, Y. Kato, A. Sugawara, K. Nakao, Exacerbation of diabetic nephropathy by Hyperlipidaemia is mediated by Toll-like receptor 4 in mice, Diabetologia, 10.1007/s00125-012-2578-1, 55, 8, 2256-2266, 2012.08, Aims/hypothesis: Hyperlipidaemia is an independent risk factor for the progression of diabetic nephropathy, but its molecular mechanism remains elusive. We investigated in mice how diabetes and hyperlipidaemia cause renal lesions separately and in combination, and the involvement of Toll-like receptor 4 (TLR4) in the process. Methods: Diabetes was induced in wild-type (WT) and Tlr4 knockout (KO) mice by intraperitoneal injection of streptozotocin (STZ). At 2 weeks after STZ injection, normal diet was substituted with a high-fat diet (HFD). Functional and histological analyses were carried out 6 weeks later. Results: Compared with treatment with STZ or HFD alone, treatment of WT mice with both STZ and HFD markedly aggravated nephropathy, as indicated by an increase in albuminuria, mesangial expansion, infiltration of macrophages and upregulation of pro-inflammatory and extracellularmatrix-associated gene expression in glomeruli. In Tlr4 KO mice, the addition of an HFD to STZ had almost no effects on the variables measured. Production of protein S100 calcium binding protein A8 (calgranulin A; S100A8), a potent ligand for TLR4, was observed in abundance in macrophages infiltrating STZ-HFD WT glomeruli and in glomeruli of diabetic nephropathy patients. High-glucose and fatty acid treatment synergistically upregulated S100a8 gene expression in macrophages from WT mice, but not from KO mice. As putative downstream targets of TLR4, phosphorylation of interferon regulatory factor 3 (IRF3) was enhanced in kidneys of WT mice co-treated with STZ and HFD. Conclusions/interpretation: Activation of S100A8/TLR4 signalling was elucidated in an animal model of diabetic glomerular injury accompanied with hyperlipidaemia, which may provide novel therapeutic targets in progressive diabetic nephropathy.. |
| 38. |
Yasuharu Watanabe, Tomoya Nakamura, Sho Ishikawa, Shiho Fujisaka, Isao Usui, Koichi Tsuneyama, Yoshinori Ichihara, Tsutomu Wada, Yoichiro Hirata, Takayoshi Suganami, Hirofumi Izaki, Shizuo Akira, Kensuke Miyake, Hiro Omi Kanayama, Michio Shimabukuro, Masataka Sata, Toshiyasu Sasaoka, Yoshihiro Ogawa, Kazuyuki Tobe, Kiyoshi Takatsu, Yoshinori Nagai, The radioprotective 105/MD-1 complex contributes to diet-induced obesity and adipose tissue inflammation, Diabetes, 10.2337/db11-1182, 61, 5, 1199-1209, 2012.05, Recent accumulating evidence suggests that innate immunity is associated with obesity-induced chronic inflammation and metabolic disorders. Here, we show that a Toll-like receptor (TLR) protein, radioprotective 105 (RP105)/myeloid differentiation protein (MD)-1 complex, contributes to high-fat diet (HFD)-induced obesity, adipose tissue inflammation, and insulin resistance. An HFD dramatically increased RP105 mRNA and protein expression in stromal vascular fraction of epididymal white adipose tissue (eWAT) in wild-type (WT) mice. RP105 mRNA expression also was significantly increased in the visceral adipose tissue of obese human subjects relative to nonobese subjects. The RP105/MD-1 complex was expressed by most adipose tissue macrophages (ATMs). An HFD increased RP105/MD-1 expression on the M1 subset of ATMs that accumulate in eWAT. Macrophages also acquired this characteristic in coculture with 3T3-L1 adipocytes. RP105 knockout (KO) and MD-1 KO mice had less HFD-induced adipose tissue inflammation, hepatic steatosis, and insulin resistance compared with wild-type (WT) and TLR4 KO mice. Finally, the saturated fatty acids, palmitic and stearic acids, are endogenous ligands for TLR4, but they did not activate RP105/MD-1. Thus, the RP105/MD-1 complex is a major mediator of adipose tissue inflammation independent of TLR4 signaling and may represent a novel therapeutic target for obesityassociated metabolic disorders.. |
| 39. |
Masayuki Ichioka, Takayoshi Suganami, Naoto Tsuda, Ibuki Shirakawa, Yoichiro Hirata, Noriko Satoh-Asahara, Yuri Shimoda, Miyako Tanaka, Misa Kim-Saijo, Yoshihiro Miyamoto, Yasutomi Kamei, Masataka Sata, Yoshihiro Ogawa, Increased expression of macrophage-inducible C-type lectin in adipose tissue of obese mice and humans, Diabetes, 10.2337/db10-0864, 60, 3, 819-826, 2011.03, OBJECTIVE - We have provided evidence that saturated fatty acids, which are released from adipocytes via macrophage-induced adipocyte lipolysis, serve as a naturally occurring ligand for the Toll-like receptor (TLR) 4 complex in macrophages, thereby aggravating obesity-induced adipose tissue inflammation. The aim of this study was to identify the molecule(s) activated in adipose tissue macrophages in obesity. RESEARCH DESIGN AND METHODS - We performed a cDNA microarray analysis of coculture of 3T3-L1 adipocytes and RAW264 macrophages. Cultured adipocytes and macrophages and the adipose tissue of obese mice and humans were used to examine mRNA and protein expression. RESULTS - We found that macrophage-inducible C-type lectin (Mincle; also called Clec4e and Clecsf9), a type II transmembrane C-type lectin, is induced selectively in macrophages during the interaction between adipocytes and macrophages. Treatment with palmitate, a major saturated fatty acid released from 3T3-L1 adipocytes, induced Mincle mRNA expression in macrophages at least partly through the TLR4/nuclear factor (NF)-κB pathway. Mincle mRNA expression was increased in parallel with macrophage markers in the adipose tissue of obese mice and humans. The obesity-induced increase in Mincle mRNA expression was markedly attenuated in C3H/HeJ mice with defective TLR4 signaling relative to control C3H/HeN mice. Notably, Mincle mRNA was expressed in bone-marrow cell (BMC)-derived proinflammatory M1 macrophages rather than in BMC-derived anti-inflammatory M2 macrophages in vitro. CONCLUSIONS - Our data suggest that Mincle is induced in adipose tissue macrophages in obesity at least partly through the saturated fatty acid/TLR4/NF-κB pathway, thereby suggesting its pathophysiologic role in obesity-induced adipose tissue inflammation.. |
| 40. |
Ayumi Sato, Hiroyuki Kawano, Tatsuto Notsu, Masahiko Ohta, Masanori Nakakuki, Kiyoshi Mizuguchi, Michiko Itoh, Takayoshi Suganami, Yoshihiro Ogawa, Antiobesity effect of eicosapentaenoic acid in high-fat/high-sucrose diet-induced obesity
Importance of hepatic lipogenesis, Diabetes, 10.2337/db09-1554, 59, 10, 2495-2504, 2010.10, OBJECTIVE - Given the pleiotropic effect of eicosapentaenoic acid (EPA), it is interesting to know whether EPA is capable of improving obesity. Here we examined the anti-obesity effect of EPA in mice with two distinct models of obesity. RESEARCH DESIGN AND METHODS - Male C57BL/6J mice were fed a high-fat/high-sucrose diet (25.0% [w/w] fat, 32.5% [w/w] sucrose) (HF/HS group) or a high-fat diet (38.1% [w/w] fat, 8.5% [w/w] sucrose) (HF group) for 4-20 weeks. A total of 5% EPA was administered by partially substituting EPA for fat in the HF/HS + EPA and HF + EPA groups. RESULTS - Both the HF/HS and HF groups similarly developed obesity. EPA treatment strongly suppresses body weight gain and obesity-related hyperglycemia and hyperinsulinemia in HF/HS-fed mice (HF/HS + EPA group), where hepatic triglyceride content and lipogenic enzymes are increased. There is no appreciable effect of EPA on body weight in HF-fed mice (HF + EPA group) without enhanced expression of hepatic lipogenic enzymes. Moreover, EPA is capable of reducing hepatic triglyceride secretion and changing VLDL fatty acid composition in the HF/HS group. By indirect calorimetry analysis, we also found that EPA is capable of increasing energy consumption in the HF/HS + EPA group. CONCLUSIONS - This study is the first demonstration that the anti-obesity effect of EPA in HF/HS-induced obesity is associated with the suppression of hepatic lipogenesis and steatosis. Because the metabolic syndrome is often associated with hepatic lipogenesis and steatosis, the data suggest that EPA is suited for treatment of the metabolic syndrome.. |
| 41. |
Noriko Satoh, Akira Shimatsu, Akihiro Himeno, Yousuke Sasaki, Hajime Yamakage, Kazunori Yamada, Takayoshi Suganami, Yoshihiro Ogawa, Unbalanced M1/M2 phenotype of peripheral blood monocytes in obese diabetic patients
Effect of pioglitazone, Diabetes care, 10.2337/dc09-1315, 33, 1, e7, 2010.01. |
| 42. |
Noriko Satoh, Akira Shimatsu, Kazuhiko Kotani, Naoki Sakane, Kazunori Yamada, Takayoshi Suganami, Hideshi Kuzuya, Yoshihiro Ogawa, Purified eicosapentaenoic acid reduces small dense LDL, remnant lipoprotein particles, and C-reactive protein in metabolic syndrome, Diabetes care, 10.2337/dc06-1179, 30, 1, 144-146, 2007.01. |
| 43. |
Takayoshi Suganami, Kanami Tanimoto-Koyama, Junko Nishida, Michiko Itoh, Xunmei Yuan, Shinji Mizuarai, Hidehito Kotani, Shoji Yamaoka, Kensuke Miyake, Seiichiro Aoe, Yasutomi Kamei, Yoshihiro Ogawa, Role of the Toll-like receptor 4/NF-κB pathway in saturated fatty acid-induced inflammatory changes in the interaction between adipocytes and macrophages, Arteriosclerosis, thrombosis, and vascular biology, 10.1161/01.ATV.0000251608.09329.9a, 27, 1, 84-91, 2007.01, OBJECTIVE - Previous studies demonstrated that obese adipose tissue is characterized by increased infiltration of macrophages, suggesting that they might represent an important source of inflammation. Using an in vitro coculture system composed of 3T3-L1 adipocytes and RAW264 macrophages, we previously demonstrated that saturated fatty acids (FAs) and tumor necrosis factor (TNF)-α derived from adipocytes and macrophages, respectively, play a major role in the coculture-induced inflammatory changes. METHODS AND RESULTS - Coculture of adipocytes and macrophages resulted in the activation of nuclear factor-κB (NF-κB), a primary regulator of inflammatory responses, in both cell types. Pharmacological inhibition of NF-κB markedly suppressed the coculture-induced production of proinflammatory cytokines and adipocyte lipolysis. Peritoneal macrophages obtained from Toll-like receptor 4 (TLR4) mutant mice exhibited marked attenuation of TNFα production in response to saturated FAs. Notably, coculture of hypertrophied adipocytes and TLR4-mutant macrophages resulted in marked inhibition of proinflammatory cytokine production and adipocyte lipolysis. We also observed that endogenous FAs, which are released from adipocytes via the β3-adrenergic stimulation, resulted in the activation of the TLR4/NF-κB pathway. CONCLUSION - These findings suggest that saturated FAs, which are released in large quantities from hypertrophied adipocytes via the macrophage-induced adipocyte lipolysis, serve as a naturally occurring ligand for TLR4, thereby inducing the inflammatory changes in both adipocytes and macrophages through NF-κB activation.. |
| 44. |
Jiyoung Park, Sik Choe Sung, A. Hyun Choi, Ho Kim Kang, Jin Yoon Myeong, Takayoshi Suganami, Yoshihiro Ogawa, Bum Kim Jae, Increase in glucose-6-phosphate dehydrogenase in adipocytes stimulates oxidative stress and inflammatory signals, Diabetes, 10.2337/db05-1570, 55, 11, 2939-2949, 2006.11, In adipocytes, oxidative stress and chronic inflammation are closely associated with metabolic disorders, including insulin resistance, obesity, cardiovascular disease, and type 2 diabetes. However, the molecular mechanisms underlying these metabolic disorders have not been thoroughly elucidated. In this report, we demonstrate that overexpression of glucose-6-phosphate dehydrogenase (G6PD) in adipocytes stimulates oxidative stress and in-flammatory responses, thus affecting the neighboring macrophages. Adipogenic G6PD overexpression promotes the expression of pro-oxidative enzymes, including inducible nitric oxide synthase and NADPH oxidase, and the activation of nuclear factor-κB (NF-κB) signaling, which eventually leads to the dysregulation of adipocytokines and inflammatory signals. Furthermore, secretory factors from G6PD-overexpressing adipocytes stimulate macrophages to express more proinflammatory cytokines and to be recruited to the adipocytes; this would cause chronic inflammatory conditions in the adipose tissue of obesity. These effects of G6PD overexpression in adipocytes were abolished by pretreatment with NF-κB inhibitors or antioxidant drugs. Thus, we propose that a high level of G6PD in adipocytes may mediate the onset of metabolic disorders in obesity by increasing the oxidative stress and inflammatory signals.. |
| 45. |
H. Makino, M. Mukoyama, K. Mori, T. Suganami, M. Kasahara, K. Yahata, T. Nagae, H. Yokoi, K. Sawai, Y. Ogawa, S. Suga, Y. Yoshimasa, A. Sugawara, I. Tanaka, K. Nakao, Transgenic overexpression of brain natriuretic peptide prevents the progression of diabetic nephropathy in mice, Diabetologia, 10.1007/s00125-006-0352-y, 49, 10, 2514-2524, 2006.10, Aims/hypothesis: Brain natriuretic peptide (BNP) is a potent vasorelaxing and natriuretic peptide that is secreted from the heart and has cardioprotective properties. We have previously generated hypotensive transgenic mice (BNP-Tg mice) that overproduce BNP in the liver, which is released into the circulation. Using this animal model, we successfully demonstrated the amelioration of renal injury after renal ablation and in proliferative glomerulonephritis. Glomerular hyperfiltration is an early haemodynamic derangement, representing one of the key mechanisms of the pathogenesis of diabetic nephropathy. Based on the suggested involvement of increased endogenous natriuretic peptides, the aim of this study was to investigate their role in the development and progression of diabetic nephropathy. Materials and methods: We evaluated the progression of renal injury and fibrogenesis in BNP-Tg mice with diabetes induced by streptozotocin. We also investigated the effect of BNP on high glucose-induced signalling abnormalities in mesangial cells. Results: After induction of diabetes, control mice exhibited progressively increased urinary albumin excretion with impaired renal function, whereas these changes were significantly ameliorated in BNP-Tg mice. Notably, diabetic BNP-Tg mice revealed minimal mesangial fibrogenesis with virtually no glomerular hypertrophy. Glomerular upregulation of extracellular signal-regulated kinase, TGF-β and extracellular matrix proteins was also significantly inhibited in diabetic BNP-Tg mice. In cultured mesangial cells, activation of the above cascade under high glucose was abrogated by the addition of BNP. Conclusions/interpretation: Chronic excess of BNP prevents glomerular injury in the setting of diabetes, suggesting that renoprotective effects of natriuretic peptides may be therapeutically applicable in preventing the progression of diabetic nephropathy.. |
| 46. |
Takayoshi Suganami, Junko Nishida, Yoshihiro Ogawa, A paracrine loop between adipocytes and macrophages aggravates inflammatory changes
Role of free fatty acids and tumor necrosis factor α, Arteriosclerosis, thrombosis, and vascular biology, 10.1161/01.ATV.0000183883.72263.13, 25, 10, 2062-2068, 2005.10, Objective - Weight gain is associated with infiltration of fat by macrophages, suggesting that they are an important source of inflammation in obese adipose tissue. Here we developed an in vitro coculture system composed of adipocytes and macrophages and examined the molecular mechanism whereby these cells communicate. Methods and Results - Coculture of differentiated 3T3-L1 adipocytes and macrophage cell line RAW264 results in the marked upregulation of proinflammatory cytokines, such as tumor necrosis factor α(TNF-α), and the downregulation of the antiinflammatory cytokine adiponectin. Such inflammatory changes are induced by the coculture without direct contact, suggesting the role of soluble factors. A neutralizing antibody to TNF-α, which occurs mostly in macrophages, inhibits the inflammatory changes in 3T3-L1, suggesting that TNF-α is a major macrophage-derived mediator of inflammation in adipocytes. Conversely, free fatty acids (FFAs) may be important adipocyte-derived mediators of inflammation in macrophages, because the production of TNF-α in RAW264 is markedly increased by palmitate, a major FFA released from 3T3-L1. The inflammatory changes in the coculture are augmented by use of either, hypertrophied 3T3-L1 or adipose stromal vascular fraction obtained from obese ob/ob mice. Conclusions - We postulate that a paracrine loop involving FFAs and TNF-α between adipocytes and macrophages establishes a vicious cycle that aggravates inflammatory changes in the adipose tissue.. |
| 47. |
Tomohiro Tanaka, Shuji Hidaka, Hiroaki Masuzaki, Shintaro Yasue, Yasuhiko Minokoshi, Ken Ebihara, Hideki Chusho, Yoshihiro Ogawa, Taro Toyoda, Kenji Sato, Fumiko Miyanaga, Muneya Fujimoto, Tsutomu Tomita, Toru Kusakabe, Nozomi Kobayashi, Hideki Tanioka, Tatsuya Hayashi, Kiminori Hosoda, Hironobu Yoshimatsu, Toshiie Sakata, Kazuwa Nakao, Skeletal muscle AMP-activated protein kinase phosphorylation parallels metabolic phenotype in leptin transgenic mice under dietary modification, Diabetes, 10.2337/diabetes.54.8.2365, 54, 8, 2365-2374, 2005.08, Leptin augments glucose and lipid metabolism independent of its effect on satiety. Administration of leptin in rodents increases skeletal muscle β-oxidation by activating AMP-activated protein kinase (AMPK). We previously reported that, as hyperleptinemic as obese human subjects, transgenic skinny mice overexpressing leptin in liver (LepTg) exhibit enhanced insulin sensitivity and lipid clearance. To assess skeletal muscle AMPK activity in leptin-sensitive and -insensitive states, we examined phosphorylation of AMPK and its target, acetyl CoA carboxylase (ACC), in muscles from LepTg under dietary modification. Here we show that phosphorylation of AMPK and ACC are chronically augmented in LepTg soleus muscle, with a concomitant increase in the AMP-to-ATP ratio and a significant decrease in tissue triglyceride content. Despite preexisting hyperleptinemia, high-fat diet (HFD)-fed LepTg develop obesity, insulin-resistance, and hyperlipidemia. In parallel, elevated soleus AMPK and ACC phosphorylation in regular diet-fed LepTg is attenuated, and tissue triglyceride content is increased in those given HFD. Of note, substitution of HFD with regular diet causes a robust recovery of soleus AMPK and ACC phosphorylation in LepTg, with a higher rate of body weight reduction and a regain of insulin sensitivity. In conclusion, soleus AMPK and ACC phosphorylation in LepTg changes in parallel with its insulin sensitivity under dietary modification, suggesting a close association between skeletal muscle AMPK activity and sensitivity to leptin.. |
| 48. |
Shigeo Yura, Hiroaki Itoh, Norimasa Sagawa, Hiroshi Yamamoto, Hiroaki Masuzaki, Kazuwa Nakao, Makoto Kawamura, Maki Takemura, Kazuyo Kakui, Yoshihiro Ogawa, Shingo Fujii, Role of premature leptin surge in obesity resulting from intrauterine undernutrition, Cell metabolism, 10.1016/j.cmet.2005.05.005, 1, 6, 371-378, 2005.06, Intrauterine undernutrition is closely associated with obesity related to detrimental metabolic sequelae in adulthood. We report a mouse model in which offspring with fetal undernutrition (UN offspring), when fed a high-fat diet (HFD), develop pronounced weight gain and adiposity. In the neonatal period, UN offspring exhibited a premature onset of neonatal leptin surge compared to offspring with intrauterine normal nutrition (NN offspring). Unexpectedly, premature leptin surge generated in NN offspring by exogenous leptin administration led to accelerated weight gain with an HFD. Both UN offspring and neonatally leptin-treated NN offspring exhibited an impaired response to acute peripheral leptin administration on a regular chow diet (RCD) with impaired leptin transport to the brain as well as an increased density of hypothalamic nerve terminals. The present study suggests that the premature leptin surge alters energy regulation by the hypothalamus and contributes to "developmental origins of health and disease.".. |
| 49. |
Yuichi Oike, Masaki Akao, Kunio Yasunaga, Toshimasa Yamauchi, Tohru Morisada, Yasuhiro Ito, Takashi Urano, Yoshishige Kimura, Yoshiaki Kubota, Hiromitsu Maekawa, Takeshi Miyamoto, Keishi Miyata, Shun Ichiro Matsumoto, Jura Sakai, Naomi Nakagata, Motohiro Takeya, Haruhiko Koseki, Yoshihiro Ogawa, Takashi Kadowaki, Toshio Suda, Angiopoietin-related growth factor antagonizes obesity and insulin resistance, Nature medicine, 10.1038/nm1214, 11, 4, 400-408, 2005.04, Angiopoietin-related growth factor (AGF), a member of the angiopoietin-like protein (Angptl) family, is secreted predominantly from the liver into the systemic circulation. Here, we show that most (>80%) of the AGF-deficient mice die at about embryonic day 13, whereas the surviving AGF-deficient mice develop marked obesity, lipid accumulation in skeletal muscle and liver, and insulin resistance accompanied by reduced energy expenditure relative to controls. In parallel, mice with targeted activation of AGF show leanness and increased insulin sensitivity resulting from increased energy expenditure. They are also protected from high-fat diet-induced obesity, insulin resistance and nonadipose tissue steatosis. Hepatic overexpression of AGF by adenoviral transduction, which leads to an approximately 2.5-fold increase in serum AGF concentrations, results in a significant (P |
| 50. |
Rika Kawakami, Yoshihiko Saito, Ichiro Kishimoto, Masaki Harada, Koichiro Kuwahara, Nobuki Takahashi, Yasuaki Nakagawa, Michio Nakanishi, Keiji Tanimoto, Satoru Usami, Shinji Yasuno, Hideyuki Kinoshita, Hideki Chusho, Naohisa Tamura, Yoshihiro Ogawa, Kazuwa Nakao, Overexpression of brain natriuretic peptide facilitates neutrophil infiltration and cardiac matrix metalloproteinase-9 expression after acute myocardial infarction, Circulation, 10.1161/01.CIR.0000147829.78357.C5, 110, 21, 3306-3312, 2004.11, Background - Recent clinical trials have shown that systemic infusion of nesiritide, a recombinant human brain natriuretic peptide (BNP), improves hemodynamic parameters in acutely decompensated hearts. This suggests that BNP exerts a direct cardioprotective effect and might thus be a useful therapeutic agent with which to treat acute myocardial infarction (MI). In the present study, we used BNP-transgenic (BNP-Tg) mice with elevated plasma BNP to determine whether and how BNP contributes to left ventricular remodeling and healing after MI. Methods and Results - We examined the accumulation of neutrophils and the expression and activation of matrix metalloproteinase (MMP)-9 in the ventricles of male BNP-Tg mice and their nontransgenic (non-Tg) littermates during the early phase after acute MI. The numbers of neutrophils infiltrating the infarcted area were significantly increased in BNP-Tg mice 3 days after MI. In addition, both the gene expression and zymographic activity of MMP-9, but not MMP-2, were significantly higher in BNP-Tg than non-Tg mice. Double immunostaining revealed that neutrophils are the main source of the MMP-9, although doxycycline, an MMP inhibitor, had no effect on neutrophil infiltration of the infarcted area in BNP-Tg mice. Conclusions - These results demonstrate that elevated plasma BNP facilitates neutrophil infiltration of the infarcted area after MI and increases the activity of the MMP-9 they produce. This suggests that BNP plays a key role in the processes of extracellular matrix remodeling and wound-healing during the early phase after acute MI.. |
| 51. |
Noriko Satoh, Mitsuhide Naruse, Takeshi Usui, Tetsuya Tagami, Takayoshi Suganami, Kazunori Yamada, Hideshi Kuzuya, Akira Shimatsu, Yoshihiro Ogawa, Leptin-to-adiponectin ratio as a potential atherogenic index in obese type 2 diabetic patients, Diabetes care, 10.2337/diacare.27.10.2488, 27, 10, 2488-2490, 2004.10. |
| 52. |
Eri Suganami, Hitoshi Takagi, Hirokazu Ohashi, Kiyoshi Suzuma, Izumi Suzuma, Hideyasu Oh, Daisuke Watanabe, Tomonari Ojima, Takayoshi Suganami, Yasushi Fujio, Kazuwa Nakao, Yoshihiro Ogawa, Nagahisa Yoshimura, Leptin stimulates ischemia-induced retinal neovascularization
Possible role of vascular endothelial growth factor expressed in retinal endothelial cells, Diabetes, 10.2337/diabetes.53.9.2443, 53, 9, 2443-2448, 2004.09, Diabetic retinopathy is the leading cause of new blindness in adults in developed countries. Leptin, an adipocyte-derived hormone, stimulates endothelial proliferation and angiogenesis. This study was designed to elucidate the pathophysiologic role of leptin in the progression of retinal neovascularization. Using the retinopathy of prematurity model, a mouse model of ischemia-induced retinal neovascularization, we have demonstrated more pronounced retinal neovascularization in 17-day-old transgenic mice overexpressing leptin than in age-matched wild-type littermates. Ischemia-induced retinal neovascularization was markedly suppressed in 17-day-old leptin-deficient ob/ob mice. Western blot analysis revealed that a biologically active leptin receptor isoform is expressed in mouse retinal endothelial cells. Leptin receptor expression was also detected in primary cultures of porcine retinal endothelial cells, where it upregulated vascular endothelial growth factor (VEGF) mRNA expression. This effect was thought to be mediated at least partly through the activation of signal transducers and activators of transcription (STAT)3, because adenoviral transfection of the dominant-negative form of STAT3 abolished the leptin-induced upregulation of VEGF mRNA expression in retinal endothelial cells. This study provides evidence that leptin stimulates the ischemia-induced retinal neovasucularization possibly through the upregulation of endothelial VEGF, thereby suggesting that leptin antagonism may offer a novel therapeutic strategy to prevent or treat diabetic retinopathy.. |
| 53. |
F. Elefteriou, S. Takeda, K. Ebihara, J. Magre, N. Patano, C. Ae Kim, Y. Ogawa, X. Liu, S. M. Ware, W. J. Craigen, J. J. Robert, C. Vinson, K. Nakao, J. Capeau, G. Karsenty, Serum leptin level is a regulator of bone mass, Proceedings of the National Academy of Sciences of the United States of America, 10.1073/pnas.0308744101, 101, 9, 3258-3263, 2004.03, Leptin is a powerful inhibitor of bone formation in vivo. This antiosteogenic function involves leptin binding to its receptors on ventromedial hypothalamic neurons, the autonomous nervous system and β-adrenergic receptors on osteoblasts. However, the mechanisms whereby leptin controls the function of ventromedial hypothalamic antiosteogenic neurons remain unclear. In this study, we compared the ability of leptin to regulate body weight and bone mass and show that leptin antiosteogenic and anorexigenic functions are affected by similar amounts of leptin. Using a knock-in of LacZ in the leptin locus, we failed to detect any leptin synthesis in the central nervous system. However, increasing serum leptin level, even dramatically, reduced bone mass. Conversely, reducing serum-free leptin level by overexpressing a soluble receptor for leptin increased bone mass. Congruent with these results, the high bone mass of lipodystrophic mice could be corrected by restoring serum leptin level, suggesting that leptin is an adipocyte product both necessary and sufficient to control bone mass. Consistent with the high bone mass phenotype of lipodystrophic mice, we observed an advanced bone age, an indirect reflection of premature bone formation, in lipodystrophic patients. Taken together, these results indicate that adipocyte-derived circulating leptin is a determinant of bone formation and suggests that leptin antiosteogenic function is conserved in vertebrates.. |
| 54. |
Akihiro Yasoda, Yasato Komatsu, Hideki Chusho, Takashi Miyazawa, Ami Ozasa, Masako Miura, Tatsuya Kurihara, Tomohiro Rogi, Shoji Tanaka, Michio Suda, Naohisa Tamura, Yoshihiro Ogawa, Kazuwa Nakao, Overexpression of CNP in chondrocytes rescues achondroplasia through a MAPK-dependent pathway, Nature medicine, 10.1038/nm971, 10, 1, 80-86, 2004.01, Achondroplasia is the most common genetic form of human dwarfism, for which there is presently no effective therapy. C-type natriuretic peptide (CNP) is a newly identified molecule that regulates endochondral bone growth through GC-B, a subtype of particulate guanylyl cyclase. Here we show that targeted overexpression of CNP in chondrocytes counteracts dwarfism in a mouse model of achondroplasia with activated fibroblast growth factor receptor 3 (FGFR-3) in the cartilage. CNP prevented the shortening of achondroplastic bones by correcting the decreased extracellular matrix synthesis in the growth plate through inhibition of the MAPK pathway of FGF signaling. CNP had no effect on the STAT-1 pathway of FGF signaling that mediates the decreased proliferation and the delayed differentiation of achondroplastic chondrocytes. These results demonstrate that activation of the CNP-GC-B system in endochondral bone formation constitutes a new therapeutic strategy for human achondroplasia.. |
| 55. |
Noriko Satoh, Yoshihiro Ogawa, Takeshi Usui, Tetsuya Tagami, Shigeo Kono, Hiroko Uesugi, Hiroyuki Sugiyama, Akira Sugawara, Kazunori Yamada, Akira Shimatsu, Hideshi Kuzuya, Kazuwa Nakao, Antiatherogenic effect of pioglitazone in type 2 diabetic patients irrespective of the responsiveness to its antidiabetic effect, Diabetes care, 10.2337/diacare.26.9.2493, 26, 9, 2493-2499, 2003.09, OBJECTIVE - Thiazolidinediones (TZDs), a class of insulin-sensitizing agents used clinically to treat type 2 diabetes, are also antiatherogenic. This study was designed to elucidate the relationship between the antiatherogenic and antidiabetic effects of pioglitazone, a TZD, in type 2 diabetic patients. RESEARCH DESIGN AND METHODS - A total of 136 Japanese type 2 diabetic patients were included and divided into two groups: the pioglitazone-treated group (30 mg daily for 3 months) (n = 70) and the untreated control group (n = 66). The changes in glycolipid metabolism as well as plasma high-sensitivity C-reactive protein (CRP), leptin, adiponectin, and pulse wave velocity (PWV) were monitored to analyze the relationship between the antiatherogenic and antidiabetic effects of pioglitazone. RESULTS - The pioglitazone treatment significantly reduced hyperglycemia, hyperinsulinemia, and HbA1c levels and increased plasma adiponectin concentrations relative to the control group (P 1c (n = 30) and responders showing > 1% of reduction (n = 40). ANCOVA revealed that treatment with pioglitazone was associated with a low CRP and PWV, independent of the changes in parameters related to glucose metabolism. CONCLUSIONS - This study represents the first demonstration of the antiatherogenic effect of pioglitazone in both nonresponders and responders with respect to its antidiabetic effect and suggests that pioglitazone can exert its antiatherogenic effect independently of its antidiabetic effect.. |
| 56. |
Hiromasa Kobayashi, Yoshihiro Ogawa, Mitsuyo Shintani, Ken Ebihara, Makiko Shimodahira, Toshio Iwakura, Megumu Hino, Takashi Ishihara, Katsuji Ikekubo, Hiroyuki Kurahachi, Kazuwa Nakao, A novel homozygous missence mutation of melanocortin-4 receptor (MC4R) in a Japanese woman with obesity, Diabetes, 10.2337/diabetes.51.1.243, 51, 1, 243-246, 2002.01, The melanocortin-4 receptor (MC4R) is a member of the seven membrane-spanning G protein-coupled receptor superfamily and signals through the activation of adenylyl cyclase. The MC4R mutations are the most common known monogenic cause of human obesity. However, no such mutations have been found in Japanese obese subjects. Here we report a novel homozygous missense mutation of MC4R (G98R) in a nondiabetic Japanese woman with severe early-onset obesity, which is located in its second transmembrane domain. Her birth weight was 3,360 g, and she gained weight progressively from 10 months of age. At 40 years of age, her weight reached 160 kg and a BMI of 62 kg/m2. Her parents, who are heterozygous for the mutation, have BMIs of 26 and 27 kg/m2. In vitro transient transfection assays revealed no discernable agonist ligand binding and cAMP production in HEK293 cells expressing the mutant receptor, indicating a severe loss-of-function mutation. This study represents the first demonstration of a pathogenic mutation of MC4R in Japan and will provide further insight into the pathophysiologic role of the hypothalamic melanocortin system in human obesity.. |
| 57. |
Mitsuyo Shintani, Haruo Nishimura, Shin Yonemitsu, Yoshihiro Ogawa, Tatsuya Hayashi, Kiminori Hosoda, Gen Inoue, Kazuwa Nakao, Troglitazone Not only Increases GLUT4 but Also Induces Its Translocation in Rat Adipocytes, Diabetes, 10.2337/diabetes.50.10.2296, 50, 10, 2296-2300, 2001.10, Thiazolidinediones, insulin-sensitizing agents, have been reported to increase glucose uptake along with the expression of glucose transporters in adipocytes and cardiomyocytes. Recently, we have further suggested that the translocation of GLUT4 is stimulated by thiazolidinediones in L6 myocytes. However, the direct effects of thiazolidinediones on translocation of glucose transporters have not yet been determined. In this study, using hemagglutinin epitope-tagged GLUT4 (GLUT4-HA), we provide direct evidence of the effect of troglitazone on the translocation of GLUT4 in rat epididymal adipocytes. Primary cultures of rat adipocytes were transiently transfected with GLUT4-HA and over-expressed eightfold compared with endogenous GLUT4 in transfected cells. A total of 24 h of treatment with troglitazone (10-4 mol/l) increased the cell surface level of GLUT4-HA by 1.5 ± 0.03-fold (P 50: from ∼0.1 to 0.03 nmol/l). These effects may partly contribute to the antidiabetic activity of troglitazone in patients with obesity and type 2 diabetes.. |
| 58. |
Hideki Chusho, Naohisa Tamura, Yoshihiro Ogawa, Akihiro Yasoda, Michio Suda, Takashi Miyazawa, Kenji Nakamura, Kazuki Nakao, Tatsuya Kurihara, Yasato Komatsu, Hiroshi Itoh, Kiyoshi Tanaka, Yoshihiko Saito, Motoya Katsuki, Kazuwa Nakao, Dwarfism and early death in mice lacking C-type natriuretic peptide, Proceedings of the National Academy of Sciences of the United States of America, 10.1073/pnas.071389098, 98, 7, 4016-4021, 2001.03, Longitudinal bone growth is determined by endochondral ossification that occurs as chondrocytes in the cartilaginous growth plate undergo proliferation, hypertrophy, cell death, and osteoblastic replacement. The natriuretic peptide family consists of three structurally related endogenous ligands, atrial, brain, and C-type natriuretic peptides (ANP, BNP, and CNP), and is thought to be involved in a variety of homeostatic processes. To investigate the physiological significance of CNP in vivo, we generated mice with targeted disruption of CNP (Nppc-/- mice). The Nppc-/- mice show severe dwarfism as a result of impaired endochondral ossification. They are all viable perinatally, but less than half can survive during postnatal development. The skeletal phenotypes are histologically similar to those seen in patients with achondroplasia, the most common genetic form of human dwarfism. Targeted expression of CNP in the growth plate chondrocytes can rescue the skeletal defect of Nppc-/- mice and allow their prolonged survival. This study demonstrates that CNP acts locally as a positive regulator of endochondral ossification in vivo and suggests its pathophysiological and therapeutic implication in some forms of skeletal dysplasia.. |
| 59. |
Takashi Kuramoto, Kazuhiro Kitada, Toshihide Inui, Yoshifumi Sasaki, Kazumi Ito, Takao Hase, Saburo Kawagachi, Yoshihiro Ogawa, Kazuwa Nakao, Gregory S. Barsh, Minako Nagao, Toshikazu Ushijima, Tadao Serikawa, Attractin/mahogany/zitter plays a critical role in myelination of the central nervous system, Proceedings of the National Academy of Sciences of the United States of America, 10.1073/pnas.98.2.559, 98, 2, 559-564, 2001.01, The rat zitter (zi) mutation induces hypomyelination and vacuolation in the central nervous system (CNS), which result in early-onset tremor and progressive flaccid paresis. By positional cloning, we found a marked decrease in Attractin (Atrn) mRNA in the brain of the zi/zi rat and identified zi as an 8-bp deletion at a splice donor site of Atrn. Atrn has been known to play multiple roles in regulating physiological processes that are involved in monocyte-T cell interaction, agouti-related hair pigmentation, and control of energy homeostasis. Rat Atrn gene encoded two isoforms, a secreted and a membrane form, as a result of alternative splicing. The zi mutation at the Atrn locus darkened coat color when introduced into agouti rats, as also described in mahogany (mg) mice, carrying the homozygous mutation at the Atrn locus. Transgenic rescue experiments showed that the membrane-type Atrn complemented both neurological alteration and abnormal pigmentation in zi/zi rats, but that the secreted-type Atrn complemented neither mutant phenotype. Furthermore, we discovered that mg mice exhibited hypomyelination and vacuolation in the CNS associated with body tremor. We conclude from these results that the membrane Atrn has a critical role in normal myelination in the CNS and would provide insights into the physiology of myelination as well as the etiology of myelin diseases.. |
| 60. |
Mitsuyo Shintani, Yoshihiro Ogawa, Ken Ebihara, Megumi Aizawa-Abe, Fumiko Miyanaga, Kazuhiko Takaya, Tatsuya Hayashi, Gen Inoue, Kiminori Hosoda, Masayasu Kojima, Kenji Kangawa, Kazuwa Nakao, Rapid publication ghrelin, an endogenous growth hormone secretagogue, is a novel orexigenic peptide that antagonizes leptin action through the activation of hypothalamic neuropeptide Y/Y1 receptor pathway, Diabetes, 10.2337/diabetes.50.2.227, 50, 2, 227-232, 2001.01, Ghrelin, an endogenous ligand for growth hormone secretagogue (GHS) receptor originally isolated from the stomach, occurs in the hypothalamic arcuate nucleus and may play a role in energy homeostasis. Synthetic GHSs have activated the hypothalamic arcuate neurons containing neuropeptide Y (NPY), suggesting the involvement of NPY in some of ghrelin actions. This study was designed to elucidate the role of ghrelin in the regulation of food intake. A single intracerebroventricular (ICV) injection of ghrelin (5-5,000 ng/rat) caused a significant and dose-related increase in cumulative food intake in rats. Ghrelin (500 ng/rat) was also effective in growth hormone-deficient spontaneous dwarf rats. Hypothalamic NPY mRNA expression was increased in rats that received a single ICV injection of ghrelin (500 ng/rat)( ∼ 6 160% of that in vehicle-treated groups, P |
| 61. |
Shin Yonemitsu, Haruo Nishimura, Mitsuyo Shintani, Ryou Inoue, Yuji Yamamoto, Hiroaki Masuzaki, Yoshihiro Ogawa, Kiminori Hosoda, Gen Inoue, Tatsuya Hayashi, Kazuwa Nakao, Troglitazone induces GLUT4 translocation in L6 myotubes, Diabetes, 10.2337/diabetes.50.5.1093, 50, 5, 1093-1101, 2001.01, A number of studies have demonstrated that insulin resistance in the skeletal muscle plays a pivotal role in the insulin resistance associated with obesity and type 2 diabetes. A decrease in GLUT4 translocation from the intracellular pool to the plasma membranes in skeletal muscles has been implicated as a possible cause of insulin resistance. Herein, we examined the effects of an insulin-sensitizing drug, troglitazone (TGZ), on glucose uptake and the translocation of GLUT4 in L6 myotubes. The prolonged exposure (24 h) of L6 myotubes to TGZ (10-5 mol/l) caused a substantial increase in the 2-deoxy-[3H]D-glucose (2-DG) uptake without changing the total amount of the glucose transporters GLUT4, GLUT1, and GLUT3. The TGZ-induced 2-DG uptake was completely abolished by cytochalasin-B (10 μmol/l). The ability of TGZ to translocate GLUT4 from light microsomes to the crude plasma membranes was greater than that of insulin. Both cycloheximide treatment (3.5 × 10-6 mol/l) and the removal of TGZ by washing reversed the 2-DG uptake to the basal level. Moreover, insulin did not enhance the TGZ-induced 2-DG uptake additively. The TGZ-induced 2-DG uptake was only partially reversed by wortmannin to 80%, and TGZ did not change the expression and the phosphorylation of protein kinase B; the expression of protein kinase C (PKC)-λ, PKC-β2, and PKC-ξ; or 5′ AMP-activated protein kinase activity. α-Tocopherol, which has a molecular structure similar to that of TGZ, did not increase 2-DG uptake. We conclude that the glucose transport in L6 myotubes exposed to TGZ for 24 h is the result of an increased translocation of GLUT4. The present results imply that the effects of troglitazone on GLUT4 translocation may include a new mechanism for improving glucose transport in skeletal muscle.. |
| 62. |
Ken Ebihara, Yoshihiro Ogawa, Hiroaki Masuzaki, Mitsuyo Shintani, Fumiko Miyanaga, Megumi Aizawa-Abe, Tatsuya Hayashi, Kiminori Hosoda, Gen Inoue, Yasunao Yoshimasa, Oksana Gavrilova, Marc L. Reitman, Kazuwa Nakao, Transgenic overexpression of leptin rescues insulin resistance and diabetes in a mouse model of lipoatrophic diabetes, Diabetes, 10.2337/diabetes.50.6.1440, 50, 6, 1440-1448, 2001.06, Lipoatrophic diabetes is caused by a deficiency of adipose tissue and is characterized by severe insulin resistance, hypoleptinemia, and hyperphagia. The A-ZIP/F-1 mouse (A-ZIPTg/+) is a model of severe lipoatrophic diabetes and is insulin resistant, hypoleptinemic, hyperphagic, and shows severe hepatic steatosis. We have also produced transgenic "skinny" mice that have hepatic overexpression of leptin (LepTg/+) and no adipocyte triglyceride stores, and are hypophagic and show increased insulin sensitivity. To explore the pathophysiological and therapeutic roles of leptin in lipoatrophic diabetes, we crossed LepTg/+ and A-ZIPTg/+ mice, producing doubly transgenic mice (LepTg/+:A-ZIPTg/+) virtually lacking adipose tissue but having greatly elevated leptin levels. The LepTg/+:A-ZIPTg/+ mice were hypophagic and showed improved hepatic steatosis. Glucose and insulin tolerance tests revealed increased insulin sensitivity, comparable to LepTg/+ mice. These effects were stable over at least 6 months of age. Pair-feeding the A-ZIPTg/+ mice to the amount of food consumed by LepTg/+:A-ZIPTg/+ mice did not improve their insulin resistance, diabetes, or hepatic steatosis, demonstrating that the beneficial effects of leptin were not due to the decreased food intake. Continuous leptin administration that elevates plasma leptin concentrations to those of LepTg/+:A-ZIPTg/+ mice also effectively improved hepatic steatosis and the disorder of glucose and lipid metabolism in A-ZIP/F-1 mice. These data demonstrate that leptin can improve the insulin resistance and diabetes of a mouse model of severe lipoatrophic diabetes, suggesting that leptin may be therapeutically useful in the long-term treatment of lipoatrophic diabetes.. |
| 63. |
Megumi Aizawa-Abe, Yoshihiro Ogawa, Hiroaki Masuzaki, Ken Ebihara, Noriko Satoh, Hidenori Iwai, Naoki Matsuoka, Tatsuya Hayashi, Kiminori Hosoda, Gen Inoue, Yasunao Yoshimasa, Kazuwa Nakao, Pathophysiological role of leptin in obesity-related hypertension, Journal of Clinical Investigation, 10.1172/JCI8341, 105, 9, 1243-1252, 2000.05, To explore the pathophysiological role of leptin in obesity-related hypertension, we examined cardiovascular phenotypes of transgenic skinny mice whose elevated plasma leptin concentrations are comparable to those seen in obese subjects. We also studied genetically obese KKA(y) mice with hyperleptinemia, in which hypothalamic melanocortin system is antagonized by ectopic expression of the agouti protein. Systolic blood pressure (BP) and urinary catecholamine excretion are elevated in transgenic skinny mice relative to nontransgenic littermates. The BP elevation in transgenic skinny mice is abolished by α1-adrenergic, β-adrenergic, or ganglionic blockers at doses that do not affect BP in nontransgenic littermates. Central administration of an α-melanocyte-stimulating hormone antagonist causes a marked increase in cumulative food intake but no significant changes in BP. The obese KKA(y) mice develop BP elevation with increased urinary catecholamine excretion relative to control KK mice. After a 2-week caloric restriction, BP elevation is reversed in nontransgenic littermates with the A(y) allele, in parallel with a reduction in plasma leptin concentrations, but is sustained in transgenic mice overexpressing leptin with the A(y) allele, which remain hyperleptinemic. This study demonstrates BP elevation in transgenic skinny mice and obese KKA(y) mice that are both hyperleptinemic, thereby suggesting the pathophysiological role of leptin in some forms of obesity-related hypertension.. |
| 64. |
Naohisa Tamura, Yoshihiro Ogawa, Hideki Chusho, Kenji Nakamura, Kazuki Nakao, Michio Suda, Masato Kasahara, Ryuju Hashimoto, Goro Katsuura, Masashi Mukoyama, Hiroshi Itoh, Yoshihiko Saito, Issei Tanaka, Hiroki Otani, Motoya Katsuki, Kazuwa Nakao, Cardiac fibrosis in mice lacking brain natriuretic peptide, Proceedings of the National Academy of Sciences of the United States of America, 10.1073/pnas.070371497, 97, 8, 4239-4244, 2000.04, Cardiac fibrosis, defined as a proliferation of interstitial fibroblasts and biosynthesis of extracellular matrix components in the ventricles of the heart, is a consequence of remodeling processes initiated by pathologic events associated with a variety of cardiovascular disorders, which leads to abnormal myocardial stiffness and, ultimately, ventricular dysfunction. Brain natriuretic peptide (BNP) is a cardiac hormone produced primarily by ventricular myocytes, and its plasma concentrations are markedly elevated in patients with congestive heart failure and acute myocardial infarction. However, its precise functional significance has been undefined. In this paper, we report the generation of mice with targeted disruption of BNP (Nppb(-/-) mice). We observed multifocal fibrotic lesions in the ventricles from Nppb(-/-) mice. No signs of systemic hypertension and ventricular hypertrophy are noted in Nppb(-/-) mice. In response to ventricular pressure overload, focal fibrotic lesions are increased in size and number in Nppb(-/- ) mice, whereas no focal fibrotic changes are found in wild-type littermates (Nppb(+/+) mice). This study establishes BNP as a cardiomyocyte-derived antifibrotic factor in vivo and provides evidence for its role as a local regulator of ventricular remodeling.. |
| 65. |
Shigeo Yura, Yoshihiro Ogawa, Norimasa Sagawa, Hiroaki Masuzaki, Hiroaki Itoh, Ken Ebihara, Megumi Aizawa-Abe, Shingo Fujii, Kazuwa Nakao, Accelerated puberty and late-onset hypothalamic hypogonadism in female transgenic skinny mice overexpressing leptin, Journal of Clinical Investigation, 10.1172/JCI8353, 105, 6, 749-755, 2000.03, Excess or loss of body fat can be associated with infertility, suggesting that adequate fat mass is essential for proper reproductive function. Leptin is an adipocyte-derived hormone that is involved in the regulation of food intake and energy expenditure, and its synthesis and secretion are markedly increased in obesity. Short-term administration of leptin accelerates the onset of puberty in normal mice and corrects the sterility of leptin-deficient ob/ob mice. These findings suggest a role for leptin as an endocrine signal between fat depots and the reproductive axis, but the effect of hyperleptinemia on the initiation and maintenance of reproductive function has not been elucidated. To address this issue, we examined the reproductive phenotypes of female transgenic skinny mice with elevated plasma leptin concentrations comparable to those in obese subjects. With no apparent adipose tissue, female transgenic skinny mice exhibit accelerated puberty and intact fertility at younger ages followed by successful delivery of healthy pups. However, at older ages, they develop hypothalamic hypogonadism characterized by prolonged menstrual cycles, atrophic ovary, reduced hypothalamic gonadotropin releasing hormone contents, and poor pituitary luteinizing hormone secretion. This study has demonstrated for the first time to our knowledge that accelerated puberty and late-onset hypothalamic hypogonadism are associated with chronic hyperleptinemia, thereby leading to a better understanding of the pathophysiological and therapeutic implication of leptin.. |
| 66. |
Yuji Yamamoto, Yasunao Yoshimasa, Makoto Koh, Junko Suga, Hiroaki Masuzaki, Yoshihiro Ogawa, Kiminori Hosoda, Haruo Nishimura, Yoshihiko Watanabe, Gen Inoue, Kazuwa Nakao, Constitutively active mitogen-activated protein kinase kinase increases GLUT1 expression and recruits both GLUT1 and GLUT4 at the cell surface in 3T3-L1 adipocytes, Diabetes, 10.2337/diabetes.49.3.332, 49, 3, 332-339, 2000.03, To address a role of mitogen-activated protein kinase (MAPK) in the regulation of glucose transport, we made a constitutively active mutant of MAPK kinase (MAPKK) and introduced it into 3T3-L1 preadipocytes by using a retrovirus-mediated transfection procedure. The deletion of 20 amino acids (those between and including 32 and 51) in the amino terminal region of Xenopus MAPKK and the replacement of serine residues on the 218 and 222 positions by glutamic acid (dSESE-MAPKK) let Xenopus MAPKK constitutively active. The isolated cell clones differently expressing dSESE-MAPKK (clone 219 higher expression, clone 233 lower expression) efficiently differentiated to adipocytes by a standard differentiation cocktail. Accordingly, the increased expression of dSESE-MAPKK protein during differentiation resulted in the increased basal MAPK activity in clone 219 adipocytes and, to a lesser extent, in clone 233 adipocytes. In contrast to clone 233 and parental adipocytes, basal 2-deoxyglucose uptake was enhanced fourfold in clone 219 adipocytes, in accordance with increased expression of GLUT1 mRNA and protein. Whereas GLUT4 mRNA was similarly expressed in all of the adipocytes, GLUT4 protein appeared to decrease in clone 219 adipocytes. More importantly, subcellular fractionation studies showed that the localization of both GLUT1 and GLUT4 in the plasma membranes (PMs) was markedly increased in the basal state in clone 219 adipocytes compared with that in clone 233 and parental adipocytes, in which both glucose transporters were preferentially located in intracellular compartments. Consequently, insulin-induced translocation of GLUT1 was abolished in clone 219 adipocytes, although the remaining intracellular GLUT4 was still responsive to insulin stimulation, which led to the movement to the PM. As combined effects on the situation of GLUT1 and GLUT4, the foldness of insulin stimulation of glucose transport based on the basal activity was reduced in cells expressing constitutively active MAPKK. These results imply that chronic activation of MAPK could be one of the mechanisms for insulin resistance.. |
| 67. |
Ken Ebihara, Yoshihiro Ogawa, Goro Katsuura, Yoshito Numata, Hiroaki Masuzaki, Noriko Satoh, Mikio Tamaki, Takeshi Yoshioka, Minoru Hayase, Naoki Matsuoka, Megumi Aizawa-Abe, Yasunao Yoshimasa, Kazuwa Nakao, Involvement of agouti-related protein, an endogenous antagonist of hypothalamic melanocortin receptor, in leptin action, Diabetes, 10.2337/diabetes.48.10.2028, 48, 10, 2028-2033, 1999.10, To understand the role of agouti-related protein (AGRP), an endogenous antagonist of hypothalamic melanocortin receptor, in leptin action, we produced a full-length recombinant AGRP and examined its effect on the satiety effect of leptin. We also studied leptin's regulation of hypothalamic AGRP mRNA expression. A single intracerebroventricular (ICV) injection of AGRP significantly increased cumulative food intake and body weight in a dose-dependent manner in rats. The leptin-induced inhibition of food intake and body weight was reversed by co-injection of AGRP in a dose-dependent manner. Hypothalamic AGRP mRNA expression was upregulated in leptin-deficient ob/ob mice and leptin receptor-deficient db/db mice and downregulated in lethal yellow agouti mice (KKA(y) mice) with hyperleptinemia. A single ICV injection of leptin reversed the increased AGRP mRNA levels in ob/ob mice but not in db/db mice. In control mice and KKA(y) mice, AGRP mRNA expression was upregulated during fasting, when plasma leptin concentrations were decreased. No significant increase in AGRP mRNA expression was noted during fasting in control mice and KKA(y) mice treated with leptin. This study provides the first direct evidence that AGRP is a negative regulator of leptin action, and leptin downregulates hypothalamic AGRP production. Because leptin is shown to increase hypothalamic α-melanocyte stimulating hormone (e-MSH) production, our data suggest that its action via the hypothalamic melanocortin system is determined by the balance between the levels of its agonist and antagonist, α-MSH and AGRP.. |
| 68. |
Yoshihiro Ogawa, Hiroaki Masuzaki, Kiminori Hosoda, Megumi Aizawa-Abe, Junko Suga, Michio Suda, Ken Ebihara, Hidenori Iwai, Naoki Matsuoka, Noriko Satoh, Hiroyuki Odaka, Hisao Kasuga, Yukio Fujisawa, Gen Inoue, Haruo Nishimura, Yasunao Yoshimasa, Kazuwa Nakao, Increased glucose metabolism and insulin sensitivity in transgenic skinny mice overexpressing leptin, Diabetes, 10.2337/diabetes.48.9.1822, 48, 9, 1822-1829, 1999.09, Excess of body fat, or obesity, is a major health problem and confers a higher risk of cardiovascular and metabolic disorders such as diabetes, hypertension, and coronary heart disease. Leptin is an adipocyte-derived satiety factor that plays an important role in the regulation of energy homeostasis, and its synthesis and secretion are markedly increased in obese subjects. To explore the metabolic consequences of an increased amount of leptin on a long-term basis in vivo, we generated transgenic skinny mice with elevated plasma leptin concentrations comparable to those in obese subjects. Overexpression of leptin in the liver has resulted in complete disappearance of white and brown adipose tissue for a long period of time in mice. Transgenic skinny mice exhibit increased glucose metabolism accompanied by the activation of insulin signaling in the skeletal muscle and liver. They also show small-sized livers with a marked decrease in glycogen and lipid storage. The phenotypes are in striking contrast to those of recently reported animal models of lipoatrophic diabetes and patients with lipoatrophic diabetes with reduced amount of leptin. The present study provides evidence that leptin is an adipocyte-derived antidiabetic hormone in vivo and suggests its pathophysiologic and therapeutic implications in diabetes.. |
| 69. |
Noriko Satoh, Yoshihiro Ogawa, Goro Katsuura, Yoshito Numata, Tetsuo Tsuji, Minoru Hayase, Ken Ebihara, Hiroaki Masuzaki, Kiminori Hosoda, Yasunao Yoshimasa, Kazuwa Nakao, Sympathetic activation of leptin via the ventromedial hypothalamus
Leptin-induced increase in catecholamine secretion, Diabetes, 10.2337/diabetes.48.9.1787, 48, 9, 1787-1793, 1999.09, Leptin is an adipocyte-derived blood-borne satiety factor that acts directly on the hypothalamus, thereby regulating food intake and energy expenditure. We have demonstrated that the hypothalamic arcuate nucleus (Arc) is a primary site of the satiety effect of leptin (Neurosci Lett 224:149-152, 1997). To explore the hypothalamic pathway of sympathetic activation of leptin, we examined the effects of a single intravenous or intracerebroventricular injection of recombinant human leptin on catecholamine secretion in rats. We also examined the effects of direct microinjection of leptin into the ventromedial hypothalamus (VMH), Arc, paraventricular nucleus (PVN), and dorsomedial hypothalamus (DMH) in rats. To further assess whether sympathetic activation of leptin is mediated via the VMH, we also examined the effects of a single intravenous injection of leptin in VMH-lesioned rats. A single injection of leptin (0.25-1.0 mg i.v./rat or 0.5-2.0 pg i.c.v./rat) increased plasma norepinephrine (NE) and epinephrine (EPI) concentrations in a dose-dependent manner. Plasma NE and EPI concentrations were increased significantly when leptin was injected directly into the VMH but were unchanged when injected into the Arc, PVN, and DMH. Plasma NE and EPI concentrations were unchanged in VMH-lesioned rats that received a single intravenous injection of leptin. The present study provides evidence that a leptin-induced increase in catecholamine secretion is mediated primarily via the VMH and suggests the presence of distinct hypothalamic pathways mediating the satiety effect and sympathetic activation of leptin.. |
| 70. |
Kazuo Chin, Kouichi Shimizu, Takaya Nakamura, Noboru Narai, Hiroaki Masuzaki, Yoshihiro Ogawa, Michiaki Mishima, Takashi Nakamura, Kazuwa Nakao, Motoharu Ohi, Changes in intra-abdominal visceral fat and serum leptin levels in patients with obstructive sleep apnea syndrome following nasal continuous positive airway pressure therapy, Circulation, 10.1161/01.CIR.100.7.706, 100, 7, 706-712, 1999.08, Background-Obstructive sleep apnea syndrome (OSAS) is a common disorder in obese subjects. Visceral fat accumulation (VFA) is a better predictor of coronary heart disease than body mass index. Leptin is a hormone involved in the control of body weight and fat distribution. The effect of nasal continuous positive airway pressure (NCPAP) treatment on VFA and serum leptin levels in OSAS patients has not been known. Methods and Results-VFA and subcutaneous fat accumulation (SFA) were assessed by CT before and after NCPAP treatment in 22 OSAS patients (mean apnea and hypopnea index >50 episodes/h). Serum leptin levels of another 21 OSAS patients were measured before and after 3 to 4 days of NCPAP to gain insight into the mechanism by which NCPAP affects fat distribution. VFA and SFA decreased significantly after 6 months of NCPAP treatment (236 ± 16 to 182±14cm2, P=0.0003 and 215±21 to 189±18 cm2 P=0.003, respectively). VFA decreased significantly in the body weight reduction group (n=9, P |
| 71. |
Hiroaki Masuzaki, Yoshihiro Ogawa, Megumi Aizawa-Abe, Kiminori Hosoda, Junko Suga, Ken Ebihara, Noriko Satoh, Hidenori Iwai, Gen Inoue, Haruo Nishimura, Yasunao Yoshimasa, Kazuwa Nakao, Glucose metabolism and insulin sensitivity in transgenic mice overexpressing leptin with lethal yellow agouti mutation
Usefulness of leptin for the treatment of obesity-associated diabetes, Diabetes, 10.2337/diabetes.48.8.1615, 48, 8, 1615-1622, 1999.08, Leptin acts as an adipocyte-derived blood-borne satiety factor that can increase glucose metabolism. To elucidate the therapeutic implications of leptin for obesity-associated diabetes, we crossed transgenic skinny mice overexpressing leptin (Tg/+), which we have developed recently, and lethal yellow KK(y) mice (A(y)/+), a genetic model for obesity-diabetes syndrome, and examined the metabolic phenotypes of F1 animals. At 6 weeks of age, plasma leptin concentrations in Tg/+ mice with the A(y) allele (Tg/+:A(y)/+) were significantly higher than those in A(y)/+ mice. Although no significant differences in body weight were noted among Tg/+:A(y)/+ mice, A(y)/+ mice, and their wild-type lean littermates (+/+), glucose and insulin tolerance tests revealed increased glucose tolerance and insulin sensitivity in Tg/+:A(y)/+ compared with A(y)/+ mice. However, at 12 weeks of age, when plasma leptin concentrations in A(y)/+ mice were comparable to those in Tg/+:A(y)/+ mice, Tg/+:A(y)/+ mice developed obesity-diabetes syndrome similar to that of A(y)[+ mice. Body weights of 12-week-old Tg/+:A(y)/+ and A(y)/+ mice were reduced to those of +/+ mice by a 3-week food restriction; when plasma leptin concentrations remained high in Tg/+:A(y)/+ mice but were markedly reduced in A(y)/+ and +/+ mice, glucose tolerance and insulin sensitivity in Tg/+:A(y)/+ mice were markedly improved as compared with A(y)/+ and +/+ mice. The present study demonstrates that hyperleptinemia can delay the onset of impaired glucose metabolism and accelerate the recovery from diabetes during caloric restriction in Tg/+:A(y)/+ mice, thereby suggesting the potential usefulness of leptin in combination with a long- term caloric restriction for the treatment of obesity-associated diabetes.. |
| 72. |
Masafumi Nakayama, Hirofumi Yasue, Michihiro Yoshimura, Yukio Shimasaki, Kiyotaka Kugiyama, Hisao Ogawa, Takeshi Motoyama, Yoshihiko Saito, Yoshihiro Ogawa, Yoshihiro Miyamoto, Kazuwa Nakao, T-786 → C mutation in the 5'-flanking region of the endothelial nitric oxide synthase gene is associated with coronary spasm, Circulation, 10.1161/01.CIR.99.22.2864, 99, 22, 2864-2870, 1999.06, Background - Coronary spasm plays an important role in the pathogenesis of ischemic heart diseases in general. However, the precise mechanism(s) responsible for coronary spasm remains to be elucidated, and we examined the molecular genetics of coronary spasm. Methods and Results - We Searched for the possible mutations in the endothelial nitric oxide synthase (eNOS) gene in patients with coronary spasm. In this study, we demonstrate the existence of 3 linked mutations in the 5'-flanking region of the eNOS gene (T-786 → C, A-922 → G, and T-1468 → A). The incidence of the mutations was significantly greater in patients with coronary spasm than in the control group (P -786 → C mutation resulted in a significant reduction in eNOS gene promoter activity (P - 922 → G nor the T-1468 → A mutation had any affect. Conclusions - Taken together, these findings strongly suggest that the T-786 → C mutation in the eNOS gene reduces the endothelial NO synthesis and predisposes the patients with the mutation to coronary spasm.. |
| 73. |
Mayumi Inoue, Hiroshi Itoh, Makiko Ueda, Takahiko Naruko, Akiko Kojima, Ryushi Komatsu, Kentaro Doi, Yoshihiro Ogawa, Naohisa Tamura, Kazuhiko Takaya, Toshio Igaki, Jun Yamashita, Tae Hwa Chun, Ken Masatsugu, Anton E. Becker, Kazuwa Nakao, Vascular endothelial growth factor (VEGF) expression in human coronary atherosclerotic lesions
Possible pathophysiological significance of VEGF in progression of atherosclerosis, Circulation, 10.1161/01.CIR.98.20.2108, 98, 20, 2108-2116, 1998.11, Background - Vascular endothelial growth factor (VEGF) is an important angiogenic factor reported to induce migration and proliferation of endothelial cells, enhance vascular permeability, and modulate thrombogenicity. VEGF expression in cultured cells (smooth muscle cells, macrophages, endothelial cells) is controlled by growth factors and cytokines. Hence, the question arises of whether VEGF could play a role in atherogenesis. Methods and Results - Frozen sections from 38 coronary artery segments were studied. The specimens were characterized as normal with diffuse intimal thickening, early atherosclerosis with hypercellularity, and advanced atherosclerosis (atheromatous plaques, fibrous plaques, and totally occlusive lesions). VEGF expression as well as the expression of 2 VEGF receptors, flt-1 and Flk-1, were studied with immunohistochemical techniques in these samples at the different stages of human coronary atherosclerosis progression. The expression of VEGF mRNA was also studied with reverse transcription-polymerase chain reaction. Normal arterial segments showed no substantial VEGF expression hypercellular and atheromatous lesions showed distinct VEGF positivity of activated endothelial cells, macrophages, and partially differentiated smooth muscle cells. VEGF positivity was also detected in endothelial cells of intraplaque microvessels within advanced lesions. In totally occlusive lesions with extensive neovascularization, intense immunostaining for VEGF was observed in accumulated macrophages and endothelial cells of the microvessels. Furthermore, VEGF mRNA expression was detected in atherosclerotic coronary segments but not in normal coronary segments. The immunostainings for flt-1 and Flk-1 were detected in aggregating macrophages in atherosclerotic lesions and also in endothelial cells of the microvessels in totally occlusive lesions. Conclusions - These results demonstrate distinct expression of VEGF and its receptors (flt-1 and Flk-1) in atherosclerotic lesions in human coronary arteries. Considering the multipotent actions of VEGF documented experimentally in vivo and in vitro, our findings suggest that VEGF may have some role in the progression of human coronary atherosclerosis, as well as in recanalization processes in obstructive coronary diseases.. |
| 74. |
Michio Suda, Yoshihiro Ogawa, Kiyoshi Tanaka, Naohisa Tamura, Akihiro Yasoda, Toshiya Takigawa, Masahiro Uehira, Hirofumi Nishimoto, Hiroshi Itoh, Yoshihiko Saito, Kohei Shiota, Kazuwa Nakao, Skeletal overgrowth in transgenic mice that overexpress brain natriuretic peptide, Proceedings of the National Academy of Sciences of the United States of America, 10.1073/pnas.95.5.2337, 95, 5, 2337-2342, 1998.03, Longitudinal bone growth is determined by the process of endochondral ossification in the cartilaginous growth plate, which is located at both ends of vertebrae and long bones and involves many systemic hormones and local regulators. Natriuretic peptides organize a family of three structurally related peptides: atrial natriuretic peptide, brain natriuretic peptide (BNP), and C-type natriuretic peptide. Atrial natriuretic peptide and BNP are cardiac hormones that are produced predominantly by the atrium and ventricle, respectively. C-type natriuretic peptide occurs in a wide variety of tissues, where it acts as a local regulator. These peptides can influence body fluid homeostasis and blood pressure control through the activation of two guanylyl cyclase (GC)-coupled natriuretic peptide receptor subtypes - GC-A and GC-B. We report here marked skeletal overgrowth in transgenic mice that overexpress BNP. Transgenic mice with elevated plasma BNP concentrations exhibited deformed bony skeletons characterized by kyphosis, elongated limbs and paws, and crooked tails, Bone abnormalities resulted from a high turnover of endochondral ossification accompanied by overgrowth of the growth plate. Studies using an in vitro organ culture of embryonic mouse tibias revealed that BNP increases the height of cartilaginous primordium directly, thereby stimulating the total longitudinal bone growth. The present study demonstrates that natriuretic peptides can affect the process of endochondral ossification.. |
| 75. |
Norimasa Sagawa, Takahide Mori, Hiroaki Masuzaki, Yoshihiro Ogawa, Kazuwa Nakao, Leptin production by hydatidiform mole, Lancet, 10.1016/S0140-6736(05)63940-2, 350, 9090, 1518-1519, 1997.11. |
| 76. |
Masaki Harada, Hiroshi Itoh, Osamu Nakagawa, Yoshihiro Ogawa, Yoshihiro Miyamoto, Koichiro Kuwahara, Emiko Ogawa, Toshio Igaki, Jun Yamashita, Izuru Masuda, Takaaki Yoshimasa, Issei Tanaka, Yoshihiko Saito, Kazuwa Nakao, Significance of ventricular myocytes and nonmyocytes interaction during cardiocyte hypertrophy
Evidence for endothelin-1 as a paracrine hypertrophic factor from cardiac nonmyocytes, Circulation, 10.1161/01.CIR.96.10.3737, 96, 10, 3737-3744, 1997.11, Background: In cardiac hypertrophy, both excessive enlargement of cardiac myocytes and progressive interstitial fibrosis are well known to occur simultaneously. In the present study, to investigate the interaction between ventricular myocytes (MCs) and cardiac nonmyocytes (NMCs), mostly fibroblasts, during cardiocytes hypertrophy, we examined the change in cell size and gene expression of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in cultured MCs as markers for hypertrophy in the neonatal rat ventricular cardiac cell culture system. Methods and Results: The size of cultured MCs significantly increased in the MC-NMC coculture. Concomitantly, secretions of ANP and BNP into culture media were significantly increased in the MC-NMC coculture compared with in the MC culture (with the possible contamination of NMC -10 to 10-6 mol/L) and transforming growth factor-β1 (TGF-β1) (10-13 to 10-9 mol/L), both of which are known to be cardiac hypertrophic factors, did not induce hypertrophy in MC culture, but both Ang II and TGF-β1 increased the size of MCs and augmented ANP and BNP productions in the MC-NMC coculture. This hypertrophic activity of Ang II and TGF-β1 was associated with the potentiation of ET-1 production in the MC- NMC coculture, and the effect of Ang II or TGF-β1 on the secretions of ANP and BNP in the coculture was significantly suppressed by pretreatment with BQ-123. Conclusions: These results demonstrate that NMCs regulate MC hypertrophy at least partially via ET-1 secretion and that the interaction between MCs and NMCs plays a critical role during the process of Ang II-or TGF-β1-induced cardiocyte hypertrophy.. |
| 77. |
N. Matsuoka, Y. Ogawa, K. Hosoda, J. Matsuda, H. Masuzaki, T. Miyawaki, N. Azuma, K. Natsui, H. Nishimura, Y. Yoshimasa, S. Nishi, D. B. Thompson, K. Nakao, Human leptin receptor gene in obese Japanese subjects
Evidence against either obesity-causing mutations or association of sequence variants with obesity, Diabetologia, 10.1007/s001250050808, 40, 10, 1204-1210, 1997.10, Leptin is an adipocyte-derived bloodborne satiety factor that acts on its cognate leptin receptor (Ob-R) in the hypothalamus, thereby regulating food intake and energy expenditure. To explore whether mutations in the Ob-R gene cause obesity in humans, we have searched for mutations in the gene for Ob-Rb, a biologically active receptor isoform, in obese Japanese subjects. We have also examined associations between such mutants and obesity in the Japanese. Genomic DNAs were used as templates in polymerase chain reaction (PCR) with primers selected to amplify exons 2 to 20 of the human Ob-Rb gene. Direct sequence analysis of the PCR products revealed 7 nucleotide sequence variants (Lys109Arg, Gln223Arg, Ser343Ser, Ser492Thr, Lys656Asn, Ala976Asp, and Pro1019Pro) in the Ob-Rb coding region from 17 obese Japanese subjects with a family history of obesity (BMI 39.3±8.4 kg/m2). No missense and nonsense mutations were found such as those in Zucker fatty (fa/fa) rats and Koletsky (fa(k)/fa(k)) rats. Nucleotide substitutions occurred at relatively high frequencies at codons 109, 223, 976, and 1019 (79, 91, 100, and 85%, respectively). Allele frequency of each variant determined by PCR-RFLP and PCR-single strand conformation polymorphism analyses showed no significant differences between 47 obese (BMI 35.1±6.5 kg/m2) and 68 non-obese (BMI 21.6±2.2 kg/m2) subjects. The present study represents the first report of sequence variants of the Ob-Rb gene in the Japanese and provides evidence against either obesity-causing mutations or association of sequence variants with obesity in obese Japanese subjects.. |
| 78. |
Hiroaki Masuzaki, Yoshihiro Ogawa, Norimasa Sagawa, Kiminori Hosoda, Tsunekazu Matsumoto, Hiroko Mise, Haruo Nishimura, Yasunao Yoshimasa, Issei Tanaka, Takahide Mori, Kazuwa Nakao, Nonadipose tissue production of leptin
Leptin as a novel placenta- derived hormone in humans, Nature medicine, 10.1038/nm0997-1029, 3, 9, 1029-1033, 1997.09, Leptin is a circulating hormone that is expressed abundantly and specifically in the adipose tissue1-5. It is involved in the regulation of energy homeostasis, as well as the neuroendocrine and reproductive systems6-11. Here, we demonstrate production of leptin by nonadipose tissue, namely, placental trophoblasts and amnion cells from uteri of pregnant women. We show that pregnant women secrete a considerable amount of leptin from the placenta into the maternal circulation as compared with nonpregnant obese women. Leptin production was also detected in a cultured human choriocarcinoma cell line, BeWo cells, and was augmented during the course of forskolin-induced differentiation of cytotrophoblasts into syncytiotrophoblasts. Plasma leptin levels were markedly elevated in patients with hydatidiform mole or choriocarcinoma and were reduced after surgical treatment or chemotherapy. Leptin is also produced by primary cultured human amnion cells and is secreted into the amniotic fluid. The present study provides evidence for leptin as a novel placenta-derived hormone in humans and suggests the physiologic and pathophysiologic significance of leptin in normal pregnancy and gestational trophoblastic neoplasms.. |
| 79. |
Kazuhiko Takaya, Yoshihiro Ogawa, Junko Hiraoka, Kiminori Hosoda, Yukio Yamori, Kazuwa Nakao, Richard J. Koletsky, Nonsense mutation of leptin receptor in the obese spontaneously hypertensive koletsky rat, Nature genetics, 10.1038/ng1096-130, 14, 2, 130-131, 1996.01. |
| 80. |
Yoshihiro Ogawa, Hiroaki Masuzaki, Naohi Isse, Taku Okazaki, Kiyoshi Mori, Michika Shigemoto, Noriko Satoh, Naohisa Tamura, Kiminori Hosoda, Yasunao Yoshimasa, Hisato Jingami, Teruo Kawada, Kazuwa Nakao, Molecular cloning of rat obese cDNA and augmented gene expression in genetically obese Zucker fatty (fa/fa) rats, Journal of Clinical Investigation, 10.1172/JCI118204, 96, 3, 1647-1652, 1995.09, The obese (ob) gene has recently been isolated through a positional cloning approach, the mutation of which causes a marked hereditary obesity and diabetes mellitus in mice. In the present study, we isolated rat ob cDNA and examined the tissue distribution of the ob gene expression in rats. We also studied the gene expression in genetically obese Zucker fatty (fa/fa) rats. The rat ob gene product, a 167 amino acid protein with a putative signal sequence, was 96 and 83% homologous to the mouse and human ob proteins, respectively. Northern blot analysis using the rat ob cDNA probe identified a single mRNA species of 4.5 kb in size in the adipose tissue, while no significant amount of ob mRNA was present in other tissues in rats. The ob gene was expressed in the adipose tissue with region specificities. The rank order of the ob mRNA level in the adipose tissue was epididymal, retroperitoneal, and pericardial white adipose tissue > mesenteric and subcutaneous white adipose tissue ≥ interscapular brown adipose tissue. The ob gene expression occurred in mature adipocytes rather than in stromal- vascular cells isolated from the rat adipose tissue. Expression of the ob gene was markedly augmented in all the adipose tissue examined in Zucker fatty (fa/fa) rats at the stage of established obesity. The present study leads to the better understanding of the physiologic and pathophysiologic roles of the ob gene.. |
| 81. |
Osamu Nakagawa, Yoshihiro Ogawa, Hiroshi Itoh, Shin Ichi Suga, Yasato Komatsu, Ichiro Kishimoto, Kazuyoshi Nishino, Takaaki Yoshimasa, Kazuwa Nakao, Rapid transcriptional activation and early mRNA turnover of brain natriuretic peptide in cardiocyte hypertrophy
Evidence for brain natriuretic peptide as an "emergency" cardiac hormone against ventricular overload, Journal of Clinical Investigation, 10.1172/JCI118162, 96, 3, 1280-1287, 1995.09, We previously demonstrated that brain natriuretic peptide (BNP) is a cardiac hormone mainly produced in the ventricle, while the major production site of atrial natriuretic peptide (ANP) is the atrium. To assess the pathophysiological role of BNP in ventricular overload, we have examined the gene expression of BNP, in comparison with that of ANP, in a model of cardiac hypertrophy using cultured neonatal rat ventricular cardiocytes. During cardiocyte hypertrophy evoked by endothelin-1, phenylephrine, or PMA, the steady state level of BNP mRNA increased as rapidly as the "immediate-early" induction of the c-fos gene expression, and reached a maximal level within 1 h. Actinomycin D, a transcriptional inhibitor, completely diminished the response, while the translational blockade with cycloheximide did not inhibit it. In contrast, ANP mRNA began to increase 3 h after the stimulation, and accumulated during cardiocyte hypertrophy. The BNP secretion from ventricular cardiocytes was also stimulated more rapidly than the ANP secretion. Furthermore, the turnover of BNP mRNA was significantly faster than that of ANP mRNA, being consistent with the existence of AUUUA motif in the 3′-untranslated region of BNP mRNA. These results demonstrate that the gene expression of BNP is distinctly regulated from that of ANP at transcriptional and posttranscriptional levels, and indicate that the characteristics of the BNP gene expression are suitable for its possible role as an "emergency" cardiac hormone against ventricular overload.. |
| 82. |
Norio Hama, Hiroshi Itoh, Gotaro Shirakami, Osamu Nakagawa, Shin Ichi Suga, Yoshihiro Ogawa, Izuru Masuda, Kuniaki Nakanishi, Takaaki Yoshimasa, Yukiya Hashimoto, Masayuki Yamaguchi, Ryouhei Hori, Hirofumi Yasue, Kazuwa Nakao, Rapid ventricular induction of brain natriuretic peptide gene expression in experimental acute myocardial infarction, Circulation, 10.1161/01.CIR.92.6.1558, 92, 6, 1558-1564, 1995.09, Background: We have demonstrated that brain natriuretic peptide (BNP) is a cardiac hormone predominantly synthesized in and secreted from the ventricle. We have also reported that, compared with atrial natriuretic peptide (ANP), the plasma concentration of BNP is increased to a greater degree in patients with congestive heart failure and more rapidly in patients with acute myocardial infarction (AMI). Methods and Results: To investigate ventricular gent expression of BNP in AMI, we analyzed plasma and ventricular BNP concentrations along with ventricular BNP mRNA in rats with AMI produced by coronary artery ligation. The BNP concentration in the left ventricle increased about 2-fold as early as 12 hours postinfarction and 5-fold 1 day postinfarction compared with sham-operated rats, whereas left ventricular ANP concentration remained unchanged within 1 day. The tissue concentration of BNP increased in the noninfarcted region as well as in the infarcted region. The surviving myocytes in and around the necrotic tissues in the infarcted region were intensely stained with the anti-BNP antiserum, indicating augmented production in the remaining myocytes in the infarcts. The BNP concentration in the right ventricle also increased about 10-fold 12 hours postinfarction, whereas the ANP concentration remained unchanged within 12 hours. Northern blot analysis revealed that BNP mRNA expression was augmented 3-fold in the left ventricle as early as 4 hours postinfarction. In contrast, ANP mRNA expression was unchanged. Reflecting the rapid induction of ventricular BNP production, the plasma BNP concentration rose to about 100 pg/mL 12 hours postinfarction (sham-operated rats, |
| 83. |
Yoshihiro Ogawa, Hiroshi Itoh, Naohisa Tamura, Shin Ichi Suga, Takaaki Yoshimasa, Masahiro Uehira, Saburo Matsuda, Shozo Shiono, Hirofumi Nishimoto, Kazuwa Nakao, Molecular cloning of the complementary DNA and gene that encode mouse brain natriuretic peptide and generation of transgenic mice that overexpress the brain natriuretic peptide gene, Journal of Clinical Investigation, 10.1172/JCI117182, 93, 5, 1911-1921, 1994.05, Brain natriuretic peptide (BNP) is a cardiac hormone that occurs predominantly in the ventricle. To study the roles of BNP in chronic cardiovascular regulation, we isolated mouse BNP cDNA and genomic clones, and generated transgenic mice with elevated plasma BNP concentration. The mouse BNP gene was organized into three exons and two introns. Two BNP mRNA species were identified, which were generated by the alternative mRNA splicing. The ventricle was a major site of BNP production in mice. Mouse preproBNP was a 121- (or 120-) residue peptide, and its COOH-terminal 45-residue peptide was the major storage form in the heart. Transgenic mice carrying the human serum amyloid P component/mouse BNP fusion gene were generated so that the hormone expression is targeted to the liver. In the liver of these mice, considerable levels of BNP mRNA and peptide were detected, reaching up to 10-fold greater than in the ventricle. These animals showed 10- to 100-fold increase in plasma BNP concentration accompanied by elevated plasma cyclic GMP concentration, and had significantly lower blood pressure than their nontransgenic littermates. The present study demonstrates that these mice provide a useful model system with which to assess the roles of BNP in cardiovascular regulation and suggests the potential usefulness of BNP as a long-term therapeutic agent.. |
| 84. |
N. Tamura, Y. Ogawa, H. Itoh, H. Arai, S. I. Suga, O. Nakagawa, Y. Komatsu, I. Kishimoto, K. Takaya, T. Yoshimasa, S. Shiono, K. Nakao, Molecular cloning of hamster brain and atrial natriuretic peptide cDNAs. Cardiomyopathic hamsters are useful models for brain and atrial natriuretic peptides, Journal of Clinical Investigation, 10.1172/jci117420, 94, 3, 1059-1068, 1994.09, Brain and atrial natriuretic peptides (BNP and ANP) are cardiac hormones with diuretic, natriuretic, and vasodilatory activities. Cardiomyopathic hamsters are widely used animal models of heart failure. Due to the structural divergence of BNP among species, examination on pathophysiological roles of BNP using cardiomyopathic hamsters is so far impossible. We therefore isolated hamster BNP and ANP cDNAs, and investigated synthesis and secretion of these peptides in normal and cardiomyopathic hamsters. The COOH- terminal 32-residue peptide of cloned hamster pre-proBNP with 122 amino acids, preceded by a single arginine residue, supposedly represents hamster BNP showing |
| 85. |
Hiroo Imura, Kazuwa Nakao, Akira Shimatsu, Yoshihiro Ogawa, Takehiro Sando, Ichiro Fujisawa, Hirohiko Yamabe, Lymphocytic Infundibuloneurohypophysitis as a Cause of Central Diabetes Insipidus, New England Journal of Medicine, 10.1056/NEJM199309023291002, 329, 10, 683-689, 1993.09, Central diabetes insipidus may be familial, secondary to hypothalamic or pituitary disorders, or idiopathic. Idiopathic central diabetes insipidus is characterized by selective hypofunction of the hypothalamic-neurohypophysial system, but its cause is unknown. We studied 17 patients with idiopathic diabetes insipidus, in whom the duration of the disorder ranged from 2 months to 20 years. Only four patients had been treated with vasopressin before the study began. All the patients underwent endocrinologic studies and magnetic resonance imaging (MRI) with a 1.5-T superconducting unit, and two patients had biopsies of the neurohypophysis or the pituitary stalk. Nine of the 17 patients had thickening of the pituitary stalk, enlargement of the neurohypophysis, or both and lacked the hyperintense signal of the normal neurohypophysis. In the remaining eight patients, the pituitary stalk and the neurohypophysis were normal, although the hyperintense signal was absent. The abnormalities of thickening and enlargement were seen on MRI only in the patients who had had diabetes insipidus for less than two years, and the abnormalities disappeared during follow-up, suggesting a self-limited process. In addition to vasopressin deficiency, two patients had mild hyperprolactinemia and nine had impaired secretory responses of growth hormone to insulin-induced hypoglycemia. The two biopsies revealed chronic inflammation, with infiltration of lymphocytes (mainly T lymphocytes) and plasma cells. Diabetes insipidus can be caused by lymphocytic infundibuloneurohypophysitis, which can be detected by MRI. The natural course of the disorder is self-limited., Central diabetes insipidus is a chronic disorder characterized by polyuria and polydipsia due to vasopressin deficiency. The disorder may be familial, idiopathic, or secondary. Familial diabetes insipidus is characterized by autosomal dominant inheritance and, at least in some families, mutations of the vasopressin-neurophysin II genes1,2. Secondary diabetes insipidus, the most common form of the disorder, is caused by tumors, infections, trauma, or other processes (such as histiocytosis and vascular lesions) that damage the hypothalamic-neurohypophysial system. Idiopathic diabetes insipidus, which accounts for 10 to 30 percent of cases of central diabetes insipidus,3,4 is characterized by selective hypofunction of…. |
| 86. |
Yasato Komatsu, Kazuwa Nakao, Itoh Hiroshi Itoh, Shin Ichi Suga, Yoshihiro Ogawa, Hiroo Imura, Vascular natriuretic peptide, The Lancet, 10.1016/0140-6736(92)92167-E, 340, 8819, 1992.09. |
| 87. |
S. I. Suga, K. Nakao, H. Itoh, Y. Komatsu, Y. Ogawa, N. Hama, H. Imura, Endothelial production of C-type natriuretic peptide and its marked augmentation by transforming growth factor-β. Possible existence of 'vascular natriuretic peptide system', Journal of Clinical Investigation, 10.1172/JCI115933, 90, 3, 1145-1149, 1992.09, C-type natriuretic peptide (CNP), the third member of the natriuretic peptide family, is thus far known to be distributed mainly in the central nervous system and is considered to act as a neuropeptide, in contrast to atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), which act as cardiac hormones. Recently, we and others have demonstrated that the ANP-B receptor, which is selectively activated by CNP, is localized not only in the central nervous system but in peripheral tissues, including blood vessels. This finding has made us speculate regarding the peripheral production of CNP. In the present study, cultured endothelial cells were examined for CNP production by RIA and Northern blot analysis. CNP-like immunoreactivity was detected in the conditioned media of endothelial cells. Northern blot analysis detected CNPmRNA with a size of 1.2 kb. In addition, transforming growth factor (TGF)-β, one of the key growth factors for vascular remodeling, markedly stimulated the expression of CNPmRNA and induced a tremendous increase in CNP secretion. We could also detect CNP transcript in the bovine thoracic aorta using the reverse transcription- polymerase chain reaction method. The present study demonstrates the endothelial production of CNP and suggests that a member of the natriuretic peptide family may act as a local regulator in vascular walls. Since evidence for the pathophysiological importance of the vascular renin-angiotensin system has been accumulating and the natriuretic peptide system is known to be antagonistic to the renin-angiotensin system, the possible existence of 'vascular natriuretic peptide system' may prove to be of physiological and clinical relevance.. |
| 88. |
M. Mukoyama, K. Nakao, K. Hosoda, S. I. Suga, Y. Saito, Y. Ogawa, G. Shirakami, M. Jougasaki, K. Obata, H. Yasue, Y. Kambayashi, K. Inouye, H. Imura, Brain natriuretic peptide as a novel cardiac hormone in humans
Evidence for an exquisite dual natriuretic peptide system, atrial natriuretic peptide and brain natriuretic peptide, Journal of Clinical Investigation, 10.1172/JCI115146, 87, 4, 1402-1412, 1991.04, Using a specific radioimmunoassay for human brain natriuretic peptide (hBNP) with a monoclonal antibody, we have investigated its synthesis, secretion, and clearance in comparison with those of atrial natriuretic peptide (ANP) in normal subjects and patients with congestive heart failure (CHF). Mean BNP-like immunoreactivity (-LI) levels in normal atrium and ventricle were 250 and 18 pmol/g, respectively. The plasma BNP-LI level in normal subjects was 0.90 ± 0.07 fmol/ml, which was 16% of the ANP-LI level. In contrast, the plasma BNP-LI level markedly increased in patients with CHF in proportion to its severity, and surpassed the ANP-LI level in severe cases. There was a significant step-up of the plasma BNP-LI level in the coronary sinus (CS) compared with that in the aortic root (Ao) and the difference between these BNP-LI levels, Δ((CS-Ao))BNP, also increased with the severity of CHF. In addition, the step-up of the BNP-LI level in the anterior interventricular vein [Δ((AIV-Ao))BNP] was comparable to Δ((CS-Ao))BNP, indicating that BNP is secreted mainly from the ventricle. Predominant BNP synthesis in the ventricle was also confirmed by Northern blot analysis. Catheterization and pharmacokinetic studies revealed that hBNP is cleared from the circulation more slowly than α-hANP; this was in part attributed to lower (about 7%) binding affinity of hBNP to clearance receptors than that of α-hANP. A predominant molecular form of BNP-LI in the heart and plasma was a 3-kD form corresponding to hBNP. These results indicate that BNP is a novel cardiac hormone secreted predominantly from the ventricle, and that the synthesis, secretion and clearance of BNP differ from those of ANP, suggesting discrete physiological and pathophysiological roles of BNP in a dual natriuretic peptide system.. |
| 89. |
Y. Ogawa, K. Nakao, M. Mukoyama, K. Hosoda, G. Shirakami, H. Arai, Y. Saito, S. I. Suga, M. Jougasaki, H. Imura, Natriuretic peptides as cardiac hormones in normotensive and spontaneously hypertensive rats
The ventricle is a major site of synthesis and secretion of brain natriuretic peptide, Circulation research, 10.1161/01.RES.69.2.491, 69, 2, 491-500, 1991.01, To study synthesis, storage, and secretion of brain natriuretic peptide (BNP) in the heart, we have measured BNP mRNA and BNP concentrations in the hearts of Wistar-Kyoto rats and also have investigated its secretion from the isolated perfused heart. The atrium expressed the BNP gene at a high level, and a considerable amount of BNP mRNA also was present in the ventricle, which corresponded to approximately 40% of the atrial BNP mRNA concentration. When tissue weight was taken into account, the total content of BNP mRNA in the ventricle was approximately threefold larger than that in the atrium, although the atrial natriuretic peptide (ANP) mRNA content in the ventricle was only 7% of that in the atrium. By contrast, the BNP concentration in the ventricle was 4.07 ± 0.97 pmol/g, which was less than 1% of that in the atrium (451 ± 86 pmol/g). The basal secretory rate of BNP from the isolated perfused whole heart was 49.3 ± 6.1 fmol/min, approximately 60% of which was maintained even after atrial removal, whereas the secretory rate of ANP was reduced to less than 5%. We also studied age-matched spontaneously hypertensive rats-stroke prone. The rank order of the BNP mRNA concentration in the hearts of these rats was left ventricle>right ventricle>right atrium=left atrium, and the total BNP mRNA content and BNP secretory rate in the ventricle were twice as large as in Wistar-Kyoto rats. These results demonstrate that BNP is a novel cardiac hormone in rats and is predominantly synthesized in and secreted from the ventricle. This is in striking contrast to ANP, which occurs mainly in the atrium. The results also suggest possible pathophysiological roles of BNP in certain cardiovascular disorders.. |
| 90. |
Masashi Mukoyama, Kazuwa Nakao, Yoshihiko Saito, Yoshihiro Ogawa, Kiminori Hosoda, Shin Ichi Suga, Gotaro Shirakami, Michihisa Jougasaki, Hiroo Imura, Increased Human Brain Natriuretic Peptide in Congestive Heart Failure, New England Journal of Medicine, 10.1056/NEJM199009133231114, 323, 11, 757-758, 1990.09, To the Editor: Brain natriuretic peptide (BNP), first isolated from the brains of pigs,1 has a striking similarity to atrial natriuretic peptide (ANP) both in structure and in peripheral and central actions.1 2 3 4 BNP is also a cardiac hormone in pigs5 and rats.6,7 Antiserums against porcine or rat BNP, however, failed to detect BNP-like immunoreactivity in human tissues, indicating the structural diversity of BNP among species. Recently, we isolated human BNP from the atrium and determined its 32-amino-acid sequence.8 We have developed a specific radioimmunoassay for human BNP8 with the use of a monoclonal antibody, modeling it on a radioimmunoassay for.. |
| 91. |
Yoshihiro Ogawa, Kazuwa Nakao, Masashi Mukoyama, Gotaro Shirakami, Hiroshi Itoh, Kiminori Hosoda, Yoshihiko Saito, Hiroshi Arai, Shin Ichi Suga, Michihisa Jougasaki, Takayuki Yamada, Yoshikazu Kambayashi, Ken Inouye, Hiroo Imura, Rat brain natriuretic peptide — tissue distribution and molecular form —, Endocrinology, 10.1210/endo-126-4-2225, 126, 4, 2225-2227, 1990.04, Using an antiserum against the ring structure of rat brain natriuretic peptide (rat BNP), we have established a specific radioimmunoassay (RIA) for rat BNP and elucidated its tissue distribution and molecular form. Rat BNP-like immunoreactivity (-LI) was detected in the highest amount in cardiac extracts (574.0 ± 138.8 pmol/g in the atrium and 4.3 ± 1.1 pmol/g in the ventricle). The secretory rate of rat BNP-LI from the perfused whole heart was.50.0 ± 1.9 fmol/min, about 60% of which was maintained even after atrial removal. We also detected rat BNP-LI throughout the spinal cord (134-175 fmol/g), although no detectable amount was present (less than 100 fmol/g) in other tissues including the brain. High performance-gel permeation chromatography and reverse phase-high performance liquid chromatography coupled with the RIA revealed that rat BNP with 45 amino acids is a major storage form as well as a secretory form of rat BNP-LI in the heart. The major component in the spinal cord was also rat BNP. These findings indicate that the tissue distribution and the processing pattern of rat BNP are different from those of atrial natriuretic peptide and porcine BNP, thereby suggesting the presence of complicated diversity of the natriuretic peptide system.. |
| 92. |
Masashi Mukoyama, Kazuwa Nakao, Yoshihiko Saito, Yoshihiro Ogawa, Kiminori Hosoda, Shin Ichi Suga, Gotaro Shirakami, Michihisa Jougasaki, Hiroo Imura, Human brain natriuretic peptide, a novel cardiac hormone, The Lancet, 10.1016/0140-6736(90)90925-U, 335, 8692, 801-802, 1990.03. |
