| Yasunari Asano | Last modified date：2024.04.09 |
Assistant Professor /
Department of Clinical Medicine /
Faculty of Medical Sciences
Papers
| 1. | Xueting Zhang,Kazufumi Yoshihara,Noriyuki Miyata,Tomokazu Hata,Altanzul Altaisaikhan,Shu Takakura,Yasunari Asano,Satoshi Izuno,Nobuyuki Sudo, Dietary tryptophan, tyrosine, and phenylalanine depletion induce reduced food intake and behavioral alterations in mice, Physiology & Behavior, 2022.02. |
| 2. | Tae Kimura-Todani,Tomokazu Hata,Noriyuki Miyata,Shu Takakura,Kazufumi Yoshihara,Xue-Ting Zhang,Yasunari Asano,Altanzul Altaisaikhan,Takamitsu Tsukahara,Nobuyuki Sudo, Dietary delivery of acetate to the colon using acylated starches as a carrier exerts anxiolytic effects in mice, Physiology & Behavior, 2020.09, [URL]. |
| 3. | Tomokazu Hata, Noriyuki Miyata, Shu Takakura, Kazufumi Yoshihara, Yasunari Asano, Tae Kimura-Todani, Makoto Yamashita, Xue-Ting Zhang, Natsuru Watanabe, Katsunaka Mikami, Yasuhiro Koga, Nobuyuki Sudo, The Gut Microbiome Derived From Anorexia Nervosa Patients Impairs Weight Gain and Behavioral Performance in Female Mice, Endocrinology, 2019.08, [URL]. |
| 4. | Tetsuya Hiramoto, Kazufumi Yoshihara, Yasunari Asano, Nobuyuki Sudo, Protective Role of the Hepatic Vagus Nerve against Liver Metastasis in Mice, NeuroImmunoModulation, 10.1159/000487483, 2018.04, Objective(s): Although accumulating evidence has shown that the autonomic nervous system is involved in liver pathology, its role in regulating cancer development remains unclear. The purpose of this study was to elucidate its detailed mechanisms. Methods: A mouse model of liver metastasis of colorectal cancer was used. To elucidate the potential mechanisms involved, we examined the effect of selective hepatic vagotomy on the survival rate and liver-to-body weight. We further evaluated the possible involvement of the hepatic sympathetic nerve fibers in this model. Results: The mortality rate and the liver-to-body weight ratio after cancer inoculation were significantly higher in the vagotomized mice than in the sham-operated mice. The vagotomized mice exhibited a transient decrease in hepatic norepinephrine levels following cancer inoculation. Interestingly, the vagotomy-induced exacerbation of liver metastasis was attenuated by supplementary norepinephrine or phenylephrine, a selective α1-adrenoceptor agonist, but not by clonidine, a selective α2-adrenoceptor agonist. Conclusion: Collectively, these results suggest that the hepatic vagus nerve may play a protective role against liver metastasis. Hepatic sympathetic nerves may also be involved as a protective efferent loop, possibly acting through the α1-adrenoceptor.. |
| 5. | Tomokazu Hata, Yasunari Asano, Kazufumi Yoshihara, Tae Kimura-Todani, Noriyuki Miyata, Xue Ting Zhang, Shu Takakura, Yuji Aiba, Yasuhiro Koga, Nobuyuki Sudo, Regulation of gut luminal serotonin by commensal microbiota in mice, PLoS One, 10.1371/journal.pone.0180745, 12, 7, 2017.07, Gut lumen serotonin (5-hydroxytryptamine: 5-HT) contributes to several gastrointestinal functions such as peristaltic reflexes. 5-HT is released from enterochromaffin (EC) cells in response to a number of stimuli, including signals from the gut microbiota. However, the specific mechanism by which the gut microbiota regulates 5-HT levels in the gut lumen has not yet been clarified. Our previous work with gnotobiotic mice showed that free catecholamines can be produced by the deconjugation of conjugated catecholamines; hence, we speculated that deconjugation by bacterial enzymes may be one of the mechanisms whereby gut microbes can produce free 5-HT in the gut lumen. In this study, we tested this hypothesis using germ-free (GF) mice and gnotobiotic mice recolonized with specific pathogen-free (SPF) fecal flora (EX-GF). The 5-HT levels in the lumens of the cecum and colon were significantly lower in the GF mice than in the EX-GF mice. Moreover, these levels were rapidly increased, within only 3 days after exposure to SPF microbiota. The majority of 5-HT was in an unconjugated, free form in the EX-GF mice, whereas approximately 50% of the 5-HT was found in the conjugated form in the GF mice. These results further support the current view that the gut microbiota plays a crucial role in promoting the production of biologically active, free 5-HT. The deconjugation of glucuronide-conjugated 5-HT by bacterial enzymes is likely one of the mechanisms contributing to free 5-HT production in the gut lumen.. |
| 6. | Michelle G. Rooks, Patrick Veiga, Analise Z. Reeve, Sydney Lavoie, Koji Yasuda, Yasunari Asano, Kazufumi Yoshihara, Monia Michaud, Leslie Wardwell-Scott, Carey Ann Gallini, Jonathan N. Glickman, Nobuyuki Sudo, Curtis Huttenhower, Cammie F. Lesser, Wendy S. Garretta, QseC inhibition as an antivirulence approach for colitis-associated bacteria, Proceedings of the National Academy of Sciences of the United States of America, 10.1073/pnas.1612836114, 114, 1, 142-147, 2017.01, Hosts and their microbes have established a sophisticated communication system over many millennia. Within mammalian hosts, this dynamic cross-talk is essential for maintaining intestinal homeostasis. In a genetically susceptible host, dysbiosis of the gut microbiome and dysregulated immune responses are central to the development of inflammatory bowel disease (IBD). Previous surveys of stool from the T-bet-/- Rag2-/- IBD mouse model revealed microbial features that discriminate between health and disease states. Enterobacteriaceae expansion and increased gene abundances for benzoate degradation, two-component systems, and bacterial motility proteins pointed to the potential involvement of a catecholamine-mediated bacterial signaling axis in colitis pathogenesis. Enterobacteriaceae sense and respond to microbiota-generated signals and host-derived catecholamines through the two-component quorum-sensing Escherichia coli regulators B and C (QseBC) system. On signal detection, QseC activates a cascade to induce virulence gene expression. Although a single pathogen has not been identified as a causative agent in IBD, adherent-invasive Escherichia coli (AIEC) have been implicated. Flagellar expression is necessary for the IBD-associated AIEC strain LF82 to establish colonization. Thus, we hypothesized that qseC inactivation could reduce LF82's virulence, and found that an absence of qseC leads to down-regulated flagellar expression and motility in vitro and reduced colonization in vivo. We extend these findings on the potential of QseC-based IBD therapeutics to three preclinical IBD models, wherein we observe that QseC blockade can effectively modulate colitogenic microbiotas to reduce intestinal inflammation. Collectively, our data support a role for QseC-mediated bacterial signaling in IBD pathogenesis and indicate that QseC inhibition may be a useful microbiota-targeted approach for disease management.. |
| 7. | Peng Zhao, Tetsuya Hiramoto, Yasunari Asano, Chiharu Kubo, Nobuyuki Sudo, Chronic psychological stress exaggerates the compound 48/80-induced scratching behavior of mice, Pharmacology Biochemistry and Behavior, 10.1016/j.pbb.2013.02.014, 105, 173-176, 2013.04, Although accumulating clinical evidence has shown that psychological stress worsens cutaneous symptoms by exaggerating scratching behavior, how the stress affects the scratching is unclear. Therefore, we herein investigated this using an animal model of scratching. Male BALB/c mice were exposed to 1 h water avoidance stress (WAS) for ten consecutive days. Twenty-four hours after the last stress session, the mice were injected into the back of the neck with a condensation product of N-methyl-p- methoxyphenethylamine with formaldehyde (compound 48/80), and their scratching behavior was then observed for 120 min. Mast cell number in the skin and histamine and corticosterone levels in the plasma were examined. The scratching number was significantly higher in the chronic WAS group than in the control group. Both mast cell number in the skin and the peak histamine in the plasma after the compound 48/80 injection were also significantly higher in the chronic WAS group in comparison to the control group. Chronic WAS delayed the peak corticosterone plasma response to the compound 48/40 injection. These findings indicate that chronic WAS exacerbates the compound 48/80-induced scratching behavior of mice. Both the increased number of skin mast cells and delayed glucocorticoid reaction may be related to this exacerbation.. |
| 8. | Yasunari Asano, Tetsuya Hiramoto, Ryo Nishino, Yuji Aiba, Tae Kimura, Kazufumi Yoshihara, Yasuhiro Koga, Nobuyuki Sudo, Critical role of gut microbiota in the production of biologically active, free catecholamines in the gut lumen of mice, American Journal of Physiology - Gastrointestinal and Liver Physiology, 10.1152/ajpgi.00341.2012, 303, 11, 2012.12, There is increasing interest in the bidirectional communication between the mammalian host and prokaryotic cells. Catecholamines (CA), candidate molecules for such communication, are presumed to play an important role in the gut lumen; however, available evidence is limited because of the lack of actual data about luminal CA. This study evaluated luminal CA levels in the gastrointestinal tract and elucidated the involvement of gut microbiota in the generation of luminal CA by comparing the findings among specific pathogen-free mice (SPF-M), germ-free mice (GF-M), and gnotobiotic mice. Substantial levels of free dopamine and norepinephrine were identified in the gut lumen of SPF-M. The free CA levels in the gut lumen were lower in GF-M than in SPF-M. The majority of CA was a biologically active, free form in SPF-M, whereas it was a biologically inactive, conjugated form in GF-M. The association of GF-M with either Clostridium species or SPF fecal flora, both of which have abundant β-glucuronidase activity, resulted in the drastic elevation of free CA. The inoculation of E. coli strain into GF-M induced a substantial amount of free CA, but the inoculation of its mutant strain deficient in the β-glucuronidase gene did not. The intraluminal administration of DA increased colonic water absorption in an in vivo ligated loop model of SPF-M, thus suggesting that luminal DA plays a role as a proabsorptive modulator of water transport in the colon. These results indicate that gut microbiota play a critical role in the generation of free CA in the gut lumen.. |
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