| 1. |
Masuda Keiji Han Xu Kato Hiroki Sato Hiroshi Zhang Yu Sun Xiao Hirofuji Yuta Yamaza Haruyoshi Yamada Aya Fukumoto, Satoshi, Dental Pulp-Derived Mesenchymal Stem Cells for Modeling Genetic Disorders, INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES, 10.3390/ijms22052269, 22, 5, 2021.03. |
| 2. |
Xu Han, Hiroki Kato, Hiroshi Sato, Yuta Hirofuji, Satoshi Fukumoto, Keiji Masuda, Accelerated osteoblastic differentiation in patient-derived dental pulp stem cells carrying a gain-of-function mutation of TRPV4 associated with metatropic dysplasia, Biochemical and Biophysical Research Communications, 10.1016/j.bbrc.2019.12.123, 523, 4, 841-846, 2020.03, Metatropic dysplasia (MD) is a congenital skeletal dysplasia characterized by severe platyspondyly and dumbbell-like long-bone deformities. These skeletal phenotypes are predominantly caused by autosomal dominant gain-of-function (GOF) mutations in transient receptor potential vanilloid 4 (TRPV4), which encodes a nonselective Ca2+-permeable cation channel. Previous studies have shown that constitutive TRPV4 channel activation leads to irregular chondrogenic proliferation and differentiation, and thus to the disorganized endochondral ossification seen in MD. Therefore, the present study investigated the role of TRPV4 in osteoblast differentiation and MD pathogenesis. Specifically, the behavior of osteoblasts differentiated from patient-derived dental pulp stem cells carrying a heterozygous single base TRPV4 mutation, c.1855C > T (p.L619F) was compared to that of osteoblasts differentiated from isogenic control cells (in which the mutation was corrected using the CRISPR/Cas9 system). The mutant osteoblasts exhibited enhanced calcification (indicated by intense Alizarin Red S staining), increased intracellular Ca2+ levels, strongly upregulated runt-related transcription factor 2 and osteocalcin expression, and increased expression and nuclear translocation of nuclear factor-activated T cell c1 (NFATc1) compared to control cells. These results suggest that the analyzed TRPV4 GOF mutation disrupts osteoblastic differentiation and induces MD-associated disorganized endochondral ossification by increasing Ca2+/NFATc1 pathway activity. Thus, inhibiting the NFATc1 pathway may be a promising potential therapeutic strategy to attenuate skeletal deformities in MD.. |
| 3. |
Kentaro Nonaka, Xu Han, Hiroki Kato, Hiroshi Sato, Haruyoshi Yamaza, Yuta Hirofuji, Keiji Masuda, Novel gain-of-function mutation of TRPV4 associated with accelerated chondrogenic differentiation of dental pulp stem cells derived from a patient with metatropic dysplasia, Biochemistry and Biophysics Reports, 10.1016/j.bbrep.2019.100648, 19, 2019.09, Metatropic dysplasia is a congenital skeletal dysplasia characterized by severe platyspondyly, dumbbell-like deformity of long tubular bones, and progressive kyphoscoliosis with growth. It is caused by mutations in the gene TRPV4, encoding the transient receptor potential vanilloid 4, which acts as a calcium channel. Many heterozygous single base mutations of this gene have been associated with the disorder, showing autosomal dominant inheritance. Although abnormal endochondral ossification has been observed by histological examination of bone in a patient with lethal metatropic dysplasia, the etiology of the disorder remains largely unresolved. As dental pulp stem cells (DPSCs) are mesenchymal stem cells that differentiate into bone lineage cells, DPSCs derived from patients with congenital skeletal dysplasia might be useful as a disease-specific cellular model for etiological investigation. The purpose of this study was to clarify the pathological association between TRPV4 mutation and chondrocyte differentiation by analyzing DPSCs from a patient with non-lethal metatropic dysplasia. We identified a novel heterozygous single base mutation, c.1855C>T in TRPV4. This was predicted to be a missense mutation, p.L619F, in putative transmembrane segment 5. The mutation was repaired by CRISPR/Cas9 system to obtain isogenic control DPSCs for further analysis. The expression of stem cell markers and fibroblast-like morphology were comparable between patient-derived mutant and control DPSCs, although expression of TRPV4 was lower in mutant DPSCs than control DPSCs. Despite the lower TRPV4 expression in mutant DPSCs, the intracellular Ca
2+
level was comparable at the basal level between mutant and control DPSCs, while its level was markedly higher following stimulation with 4α-phorbol 12,13-didecanoate (4αPDD), a specific agonist for TRPV4, in mutant DPSCs than in control DPSCs. In the presence of 4αPDD, we observed accelerated early chondrocyte differentiation and upregulated mRNA expression of SRY-box 9 (SOX9) in mutant DPSCs. Our findings suggested that the novel missense mutation c.1855C>T of TRPV4 was a gain-of-function mutation leading to enhanced intracellular Ca
2+
level, which was associated with accelerated chondrocyte differentiation and SOX9 upregulation. Our results also suggest that patient-derived DPSCs can be a useful disease-specific cellular model for elucidating the pathological mechanism of metatropic dysplasia.. |
| 4. |
Yu Zhang, Xiao Sun, Xu Han, Hiroshi Sato, Yuta Hirofuji, Keiji Masuda, Protective effect of folic acid on vulnerability to oxidative stress in dental pulp stem cells of deciduous teeth from children with orofacial clefts, Biochemical and Biophysical Research Communications, 10.1016/j.bbrc.2019.06.031, 516, 1, 127-132, 2019.08, Orofacial clefts (OFCs) are among the most common congenital craniofacial malformations, including cleft lip with or without cleft palate as the core symptoms. Developmental or functional defects in neural crest cells (NCCs) that contribute to craniofacial morphogenesis are involved in OFC development. Previous studies have suggested that oxidative stress in NCCs is involved in the development of OFCs, suggesting that the anti-oxidative activity of folic acid (FA) could have protective effects. However, studies of human-derived NCCs are limited, as these cells are predominantly active during the embryonic stage. In this study, the effects of oxidative stress and FA were evaluated in human OFCs. In particular, NCC-derived stem cells from human exfoliated deciduous teeth (SHEDs) were obtained from 3 children with non-syndromic cleft lip with cleft palate (CLPs) and from 3 healthy children (CTRLs). Mitochondrial reactive oxygen species (ROS) levels were significantly higher in CLPs than in CTRLs and were associated with lower mRNA expression levels of superoxide dismutase 1 (SOD1) and decreased cell mobility. In addition, significantly greater vulnerability to pyocyanin-induced ROS, mimicking exogenous ROS, was observed in CLPs than in CTRLs. These vulnerabilities to endogenous and exogenous ROS in CLPs were significantly improved by FA. These results indicated that the transcriptional dysregulation of SOD1 in NCCs is an oxidative stress-related pathological factor in OFCs, providing novel evidence for the benefits of perinatal anti-oxidant supplementation, including FA, for the management of these common deformities.. |
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Xu Han, Kentaro Nonaka, Hiroki Kato, Haruyoshi Yamaza, Hiroshi Sato, Takashi Kifune, Yuta Hirofuji, Keiji Masuda, Osteoblastic differentiation improved by bezafibrate-induced mitochondrial biogenesis in deciduous tooth-derived pulp stem cells from a child with Leigh syndrome, Biochemistry and Biophysics Reports, 10.1016/j.bbrep.2018.11.003, 17, 32-37, 2019.03, Leigh syndrome is a highly heterogeneous condition caused by pathological mutations in either nuclear or mitochondrial DNA regions encoding molecules involved in mitochondrial oxidative phosphorylation, in which many organs including the brain can be affected. Among these organs, a high incidence of poor bone health has been recognized in primary mitochondrial diseases including Leigh syndrome. However, the direct association between mitochondrial dysfunction and poor bone health has not been fully elucidated. Mitochondrial biosynthesis is a potential therapeutic target for this syndrome, as it can ameliorate the impairment of oxidative phosphorylation without altering these gene mutations. A recent study has shown the impaired osteogenesis in the dental pulp stem cells derived from the deciduous teeth of a child with Leigh syndrome, harboring the heteroplasmic mutation G13513A in the mitochondrial DNA region encoding the ND5 subunit of the respiratory chain complex I. The present study aimed to investigate whether mitochondrial biogenesis could be a therapeutic target for improving osteogenesis, using the same stem cells in a patient-specific cellular model. For this purpose, bezafibrate was used because it has been reported to induce mitochondrial biogenesis as well as to improve bone metabolism and osteoporosis. Bezafibrate clearly improved the differentiation of patient-derived stem cells into osteoblasts and the mineralization of differentiated osteoblasts. The mRNA expression of peroxisome proliferator-activated receptor-gamma coactivator-1α, ATP production, and mitochondrial Ca2+ levels were all significantly increased by bezafibrate in the patient-derived cells. In addition, the increased amount and morphological shift from the fragmentary to network shape associated with DRP1 downregulation were also observed in the bezafibrate-treated patient-derived cells. These results suggest that mitochondrial biogenesis may be a potential therapeutic target for improving osteogenesis in patients with Leigh syndrome, and bezafibrate may be one of the candidate treatment agents.. |
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Yu Zhang, Hiroki Kato, Hiroshi Sato, Haruyoshi Yamaza, Yuta Hirofuji, Xu Han, Keiji Masuda, Kazuaki Nonaka, Folic acid-mediated mitochondrial activation for protection against oxidative stress in human dental pulp stem cells derived from deciduous teeth, Biochemical and Biophysical Research Communications, 10.1016/j.bbrc.2018.11.169, 508, 3, 850-856, 2019.01, Enzymatic antioxidant systems, mainly involving mitochondria, are critical for minimizing the harmful effects of reactive oxygen species, and these systems are enhanced by interactions with nonenzymatic antioxidant nutrients. Because fetal growth requires extensive mitochondrial respiration, pregnant women and fetuses are at high risk of exposure to excessive reactive oxygen species. The enhancement of the antioxidant system, e.g., by nutritional management, is therefore critical for both the mother and fetus. Folic acid supplementation prevents homocysteine accumulation and epigenetic dysregulation associated with one-carbon metabolism. However, few studies have examined the antioxidant effects of folic acid for healthy pregnancy outcomes. The purpose of this study was to elucidate the association between the antioxidant effect of folic acid and mitochondria in undifferentiated cells during fetal growth. Neural crest-derived dental pulp stem cells of human exfoliated deciduous teeth were used as a model of undifferentiated cells in the fetus. Pyocyanin induced excessive reactive oxygen species, resulting in a decrease in cell growth and migration accompanied by mitochondrial fragmentation and inactivation in dental pulp stem cells. This damage was significantly improved by folic acid, along with decreased mitochondrial reactive oxygen species, PGC-1α upregulation, DRP1 downregulation, mitochondrial elongation, and increased ATP production. Folic acid may protect undifferentiated cells from oxidative damage by targeting mitochondrial activation. These results provide evidence for a new benefit of folic acid in pregnant women and fetuses.. |
| 7. |
Huong Thi Nguyen Nguyen, Hiroki Kato, Keiji Masuda, Haruyoshi Yamaza, Yuta Hirofuji, Hiroshi Sato, Thanh Thi Mai Pham, Fumiko Takayama, Yasunari Sakai, Shoichi Ohga, Tomoaki Taguchi, Kazuaki Nonaka, Impaired neurite development associated with mitochondrial dysfunction in dopaminergic neurons differentiated from exfoliated deciduous tooth-derived pulp stem cells of children with autism spectrum disorder, Biochemistry and Biophysics Reports, 10.1016/j.bbrep.2018.09.004, 16, 24-31, 2018.12, Autism spectrum disorder (ASD) is a highly heterogeneous neurodevelopmental disorder characterized by impaired social interactions, restrictive interests, and repetitive stereotypic behaviors. Among the various mechanisms underlying the pathogenesis of ASD, dysfunctions of dopaminergic signaling and mitochondria have been hypothesized to explain the core symptoms of children with ASD. However, only a few studies focusing on the pathological association between dopaminergic neurons (DN) and mitochondria in ASD have been performed using patient-derived stem cells and in vitro differentiated neurons. Stem cells from human exfoliated deciduous teeth (SHED) are neural crest-derived mesenchymal stem cells present in the dental pulp of exfoliated deciduous teeth; these cells can differentiate into dopaminergic neurons (DN) in vitro. This study aimed to investigate the pathological association between development of DN and mitochondria in ASD by using SHED as a disease- or patient-specific cellular model. The SHED obtained from three children with ASD and three typically developing children were differentiated into DN, and the neurobiology of these cells was examined. The DN derived from children with ASD showed impaired neurite outgrowth and branching, associated with decreased mitochondrial membrane potential, ATP production, number of mitochondria within the neurites, amount of mitochondria per cell area and intracellular calcium level. In addition, impaired neurite outgrowth and branching of ASD-derived DN were not improved by brain-derived neurotrophic factor (BDNF), suggesting impairment of the BDNF signaling pathway in ASD. These results imply that intracerebral dopamine production may have decreased in these children. The earliest age at which deciduous teeth spontaneously exfoliate in humans, and SHED can be noninvasively collected, is approximately 6 years. Our results suggest that in vitro analysis of SHED-derived DN obtained from children with ASD provides neurobiological information that may be useful in determining treatment strategies in the early stages of ASD.. |
| 8. |
Thanh Thi Mai Pham, Hiroki Kato, Haruyoshi Yamaza, Keiji Masuda, Yuta Hirofuji, Hiroshi Sato, Huong Thi Nguyen Nguyen, Xu Han, Yu Zhang, Tomoaki Taguchi, Kazuaki Nonaka, Altered development of dopaminergic neurons differentiated from stem cells from human exfoliated deciduous teeth of a patient with Down syndrome, BMC neurology, 10.1186/s12883-018-1140-2, 18, 1, 2018.08, Background: Down syndrome (DS) is a common developmental disorder resulting from the presence of an additional copy of chromosome 21. Abnormalities in dopamine signaling are suggested to be involved in cognitive dysfunction, one of the symptoms of DS, but the pathophysiological mechanism has not been fully elucidated at the cellular level. Stem cells from human exfoliated deciduous teeth (SHED) can be prepared from the dental pulp of primary teeth. Importantly, SHED can be collected noninvasively, have multipotency, and differentiate into dopaminergic neurons (DN). Therefore, we examined dopamine signaling in DS at the cellular level by isolating SHED from a patient with DS, differentiating the cells into DN, and examining development and function of DN. Methods: Here, SHED were prepared from a normal participant (Ctrl-SHED) and a patient with DS (DS-SHED). Initial experiments were performed to confirm the morphological, chromosomal, and stem cell characteristics of both SHED populations. Next, Ctrl-SHED and DS-SHED were differentiated into DN and morphological analysis of DN was examined by immunostaining. Functional analysis of DN was performed by measuring extracellular dopamine levels under basal and glutamate-stimulated conditions. In addition, expression of molecules involved in dopamine homeostasis was examined by quantitative real-time polymerase chain reaction and immunostaining. Statistical analysis was performed using two-tailed Student's t-tests. Results: Compared with Ctrl-SHED, DS-SHED showed decreased expression of nestin, a neural stem-cell marker. Further, DS-SHED differentiated into DN (DS-DN) exhibiting decreased neurite outgrowth and branching compared with Ctrl-DN. In addition, DS-DN dopamine secretion was lower than Ctrl-DN dopamine secretion. Moreover, aberrant expression of molecules involved in dopaminergic homeostasis was observed in DS-DN. Conclusions: Our results suggest that there was developmental abnormality and DN malfunction in the DS-SHED donor in this study. In the future, to clarify the detailed mechanism of dopamine-signal abnormality due to DN developmental and functional abnormalities in DS, it is necessary to increase the number of patients for analysis. Non-invasively harvested SHED may be very useful in the analysis of DS pathology.. |
| 9. |
Saki Hirofuji, Yuta Hirofuji, Hiroki Kato, Keiji Masuda, Haruyoshi Yamaza, Hiroshi Sato, Fumiko Takayama, Michiko Torio, Yasunari Sakai, Shoichi Ohga, Tomoaki Taguchi, Kazuaki Nonaka, Mitochondrial dysfunction in dopaminergic neurons differentiated from exfoliated deciduous tooth-derived pulp stem cells of a child with Rett syndrome, Biochemical and Biophysical Research Communications, 10.1016/j.bbrc.2018.03.077, 498, 4, 898-904, 2018.04, Rett syndrome is an X-linked neurodevelopmental disorder associated with psychomotor impairments, autonomic dysfunctions and autism. Patients with Rett syndrome have loss-of-function mutations in MECP2, the gene encoding methyl-CpG-binding protein 2 (MeCP2). Abnormal biogenic amine signaling and mitochondrial function have been found in patients with Rett syndrome; however, few studies have analyzed the association between these factors. This study investigated the functional relationships between mitochondria and the neuronal differentiation of the MeCP2-deficient stem cells from the exfoliated deciduous teeth of a child with Rett syndrome. An enrolled subject in this study was a 5-year-old girl carrying a large deletion that included the methyl-CpG-binding domain, transcriptional repression domain, and nuclear localization signal of MECP2. Using the single-cell isolation technique, we found that the two populations of MeCP2-expressing and MeCP2-deficient stem cells kept their MECP2 expression profiles throughout the stages of cell proliferation and neuronal differentiation in vitro. Neurite outgrowth and branching were attenuated in MeCP2-deficient dopaminergic neurons. MeCP2-deficient cells showed reduced mitochondrial membrane potential, ATP production, restricted mitochondrial distribution in neurites, and lower expression of a central mitochondrial fission factor, dynamin-related protein 1 than MeCP2-expressing cells. These data indicated that MeCP2-deficiency dysregulates the expression of mitochondrial factors required for the maturation of dopaminergic neurons. This study also provides insight into the pathogenic mechanism underlying dysfunction of the intracerebral dopaminergic signaling pathway in Rett syndrome.. |
| 10. |
Yumiko I. Matsuishi, Hiroki Kato, Keiji Masuda, Haruyoshi Yamaza, Yuta Hirofuji, Hiroshi Sato, Hiroko Wada, Tamotsu Kiyoshima, Kazuaki Nonaka, Accelerated dentinogenesis by inhibiting the mitochondrial fission factor, dynamin related protein 1, Biochemical and Biophysical Research Communications, 10.1016/j.bbrc.2017.12.026, 495, 2, 1655-1660, 2018.01, Undifferentiated odontogenic epithelium and dental papilla cells differentiate into ameloblasts and odontoblasts, respectively, both of which are essential for tooth development. These differentiation processes involve dramatic functional and morphological changes of the cells. For these changes to occur, activation of mitochondrial functions, including ATP production, is extremely important. In addition, these changes are closely related to mitochondrial fission and fusion, known as mitochondrial dynamics. However, few studies have focused on the role of mitochondrial dynamics in tooth development. The purpose of this study was to clarify this role. We used mouse tooth germ organ cultures and a mouse dental papilla cell line with the ability to differentiate into odontoblasts, in combination with knockdown of the mitochondrial fission factor, dynamin related protein (DRP)1. In organ cultures of the mouse first molar, tooth germ developed to the early bell stage. The amount of dentin formed under DRP1 inhibition was significantly larger than that of the control. In experiments using a mouse dental papilla cell line, differentiation into odontoblasts was enhanced by inhibiting DRP1. This was associated with increased mitochondrial elongation and ATP production compared to the control. These results suggest that DRP1 inhibition accelerates dentin formation through mitochondrial elongation and activation. This raises the possibility that DRP1 might be a therapeutic target for developmental disorders of teeth.. |
| 11. |
Yuichi Matsushima, Yuta Hirofuji, Masamune Aihara, Song Yue, Takeshi Uchiumi, Laurie S. Kaguni, Dongchon Kang, Drosophila protease ClpXP specifically degrades DmLRPPRC1 controlling mitochondrial mRNA and translation, Scientific Reports, 10.1038/s41598-017-08088-6, 7, 1, 2017.12, ClpXP is the major protease in the mitochondrial matrix in eukaryotes, and is well conserved among species. ClpXP is composed of a proteolytic subunit, ClpP, and a chaperone-like subunit, ClpX. Although it has been proposed that ClpXP is required for the mitochondrial unfolded protein response, additional roles for ClpXP in mitochondrial biogenesis are unclear. Here, we found that Drosophila leucine-rich pentatricopeptide repeat domain-containing protein 1 (DmLRPPRC1) is a specific substrate of ClpXP. Depletion or introduction of catalytically inactive mutation of ClpP increases DmLRPPRC1 and causes non-uniform increases of mitochondrial mRNAs, accumulation of some unprocessed mitochondrial transcripts, and modest repression of mitochondrial translation in Drosophila Schneider S2 cells. Moreover, DmLRPPRC1 over-expression induces the phenotypes similar to those observed when ClpP is depleted. Taken together, ClpXP regulates mitochondrial gene expression by changing the protein level of DmLRPPRC1 in Drosophila Schneider S2 cells.. |
| 12. |
Hiroki Kato, Xu Han, Haruyoshi Yamaza, Keiji Masuda, Yuta Hirofuji, Hiroshi Sato, Thanh Thi Mai Pham, Tomoaki Taguchi, Kazuaki Nonaka, Direct effects of mitochondrial dysfunction on poor bone health in Leigh syndrome, Biochemical and Biophysical Research Communications, 10.1016/j.bbrc.2017.09.045, 493, 1, 207-212, 2017.11, Mitochondrial diseases are the result of aberrant mitochondrial function caused by mutations in either nuclear or mitochondrial DNA. Poor bone health has recently been suggested as a symptom of mitochondrial diseases; however, a direct link between decreased mitochondrial function and poor bone health in mitochondrial disease has not been demonstrated. In this study, stem cells from human exfoliated deciduous teeth (SHED) were isolated from a child with Leigh syndrome (LS), a mitochondrial disease, and the effects of decreased mitochondrial function on poor bone health were analyzed. Compared with control SHED, LS SHED displayed decreased osteoblastic differentiation and calcium mineralization. The intracellular and mitochondrial calcium levels were lower in LS SHED than in control SHED. Furthermore, the mitochondrial activity of LS SHED was decreased compared with control SHED both with and without osteoblastic differentiation. Our results indicate that decreased osteoblast differentiation potential and osteoblast function contribute to poor bone health in mitochondrial diseases.. |
| 13. |
Hiroshi Sato, Hiroki Kato, Haruyoshi Yamaza, Keiji Masuda, Huong Thi Nguyen Nguyen, Thanh Thi Mai Pham, Xu Han, Yuta Hirofuji, Kazuaki Nonaka, Engineering of Systematic Elimination of a Targeted Chromosome in Human Cells, BioMed Research International, 10.1155/2017/6037159, 2017, 2017.01, Embryonic trisomy leads to abortion or congenital genetic disorders in humans. The most common autosomal chromosome abnormalities are trisomy of chromosomes 13, 18, and 21. Although alteration of gene dosage is thought to contribute to disorders caused by extra copies of chromosomes, genes associated with specific disease phenotypes remain unclear. To generate a normal cell from a trisomic cell as a means of etiological analysis or candidate therapy for trisomy syndromes, we developed a system to eliminate a targeted chromosome from human cells. Chromosome 21 was targeted by integration of a DNA cassette in HeLa cells that harbored three copies of chromosome 21. The DNA cassette included two inverted loxP sites and a herpes simplex virus thymidine kinase (HSV-tk) gene. This system causes missegregation of chromosome 21 after expression of Cre recombinase and subsequently enables the selection of cells lacking the chromosome by culturing in a medium that includes ganciclovir (GCV). Cells harboring only two copies of chromosome 21 were efficiently induced by transfection of a Cre expression vector, indicating that this approach is useful for eliminating a targeted chromosome.. |
| 14. |
Hiroki Kato, Thanh Thi Mai Pham, Haruyoshi Yamaza, Keiji Masuda, Yuta Hirofuji, Xu Han, Hiroshi Sato, Tomoaki Taguchi, Kazuaki Nonaka, Mitochondria regulate the differentiation of stem cells from human exfoliated deciduous teeth, Cell Structure and Function, 10.1247/csf.17012, 42, 2, 105-116, 2017.01, Stem cells from human exfoliated deciduous teeth (SHED) are isolated from the dental pulp tissue of primary teeth and can differentiate into neuronal cells. Although SHED are a desirable type of stem cells for transplantation therapy and for the study of neurological diseases, a large part of the neuronal differentiation machinery of SHED remains unclear. Recent studies have suggested that mitochondrial activity is involved in the differentiation of stem cells. In the present work, we investigated the neuronal differentiation machinery of SHED by focusing on mitochondrial activity. During neuronal differentiation of SHED, we observed increased mitochondrial membrane potential, increased mitochondrial DNA, and elongated mitochondria. Furthermore, to examine the demand for mitochondrial activity in neuronal differentiation, we then differentiated SHED into neuronal cells in the presence of rotenone, an inhibitor of mitochondrial respiratory chain complex I, and carbonyl cyanide m-chlorophenyl hydrazone (CCCP), a mitochondrial uncoupler, and found that neuronal differentiation was inhibited by treatment with rotenone and CCCP. These results indicated that increased mitochondrial activity was crucial for the neuronal differentiation of SHED.. |
| 15. |
Jingxian Fang, Haruyoshi Yamaza, Takeshi Uchiumi, Yoshihiro Hoshino, Keiji Masuda, Yuta Hirofuji, Frank A.D.T.G. Wagener, Dongchon Kang, Kazuaki Nonaka, Dihydroorotate dehydrogenase depletion hampers mitochondrial function and osteogenic differentiation in osteoblasts, European Journal of Oral Sciences, 10.1111/eos.12270, 124, 3, 241-245, 2016.06, Mutation of the dihydroorotate dehydrogenase (DHODH) gene is responsible for Miller syndrome, which is characterized by craniofacial malformations with limb abnormalities. We previously demonstrated that DHODH was involved in forming a mitochondrial supercomplex and that mutated DHODH led to protein instability, loss of enzyme activity, and increased levels of reactive oxygen species in HeLa cells. To explore the etiology of Miller syndrome in more detail, we investigated the effects of DHODH inhibition in the cells involved in skeletal structure. Dihydroorotate dehydrogenase in MC3T3-E1 cells derived from mouse calvaria osteoblast precursor cells was knocked down by specific small interfering RNAs (siRNAs), and cell proliferation, ATP production, and expression of bone-related genes were investigated in these cells. After depletion of DHODH using specific siRNAs, inhibition of cell proliferation and cell cycle arrest occurred in MC3T3-E1 cells. In addition, ATP production was reduced in whole cells, especially in mitochondria. Furthermore, the levels of runt-related transcription factor 2 (Runx2) and osteocalcin (Ocn) mRNAs were lower in DHODH siRNA-treated cells compared with controls. These data suggest that depletion of DHODH affects the differentiation and maturation of osteoblasts. This study shows that mitochondrial dysfunction by DHODH depletion in osteoblasts can be directly linked to the abnormal bone formation in Miller syndrome.. |
