研究者総覧

渡邉 和寿 (ワタナベ カズヒサ)

  • 人類遺伝学研究部 講師
メールアドレス: kwatanabejichi.ac.jp
Last Updated :2021/09/22

研究者情報

学位

  • 博士(医学)(筑波大学大学院)

ホームページURL

J-Global ID

研究キーワード

  • 分子生物学   生活習慣病   糖尿病   肥満   

研究分野

  • ライフサイエンス / 分子生物学
  • ライフサイエンス / 病態医化学

経歴

  • 2019年09月 - 現在  自治医科大学医学部講師
  • 2013年10月 - 2019年08月  自治医科大学医学部助教
  • 2013年04月 - 2013年09月  Columbia University,Naomi Berrie Diabetes Center and Department of Pediatrics -Associate Research Scientist
  • 2010年04月 - 2013年03月  Columbia University,Naomi Berrie Diabetes Center and Department of Pediatrics -Postdoctoral Fellow
  • 2009年04月 - 2010年03月  Columbia University,Naomi Berrie Diabetes Center and Department of Pediatrics -日本学術振興会特別研究員(PD)

学歴

  • 2005年04月 - 2009年03月   筑波大学   人間総合科学研究科   先端応用医学専攻
  • 2003年04月 - 2005年03月   筑波大学   医科学研究科   医科学専攻
  • 1999年04月 - 2003年03月   日本大学   生物資源科学部   農芸化学科

所属学協会

  • 日本肥満学会   日本糖尿病学会   日本栄養・食糧学会   

研究活動情報

論文

  • Watanabe K, Yokota K, Yoshida K, Matsumoto A, Iwamoto S
    Biochemistry and biophysics reports 20 100676  2019年12月 [査読有り][通常論文]
  • Watanabe K, Yoshida K, Iwamoto S
    Journal of diabetes investigation 10 4 925 - 932 2019年07月 [査読有り][通常論文]
  • Elizabeth J. Millings, Maria Caterina De Rosa, Sarah Fleet, Kazuhisa Watanabe, Richard Rausch, Dieter Egli, Gen Li, Charles A. Leduc, Yiying Zhang, Stuart G. Fischer, Rudolph L. Leibel
    PLoS ONE 13 5 e0197548  2018年05月 [査読有り][通常論文]
     
    We have previously reported that Ildr2 knockdown via adenovirally-delivered shRNA causes hepatic steatosis in mice. In the present study we investigated hepatic biochemical and anatomic phenotypes of Cre-mediated Ildr2 knock-out mice. Liver-specific Ildr2 knock-out mice were generated in C57BL/6J mice segregating for a floxed (exon 1) allele of Ildr2, using congenital and acute (10-13-week-old male mice) Cre expression. In addition, Ildr2 shRNA was administered to Ildr2 knock-out mice to test the effects of Ildr2 shRNA, per se, in the absence of Ildr2 expression. RNA sequencing was performed on livers of these knockdown and knockout mice. Congenital and acute liver-specific and hepatocyte-specific knockout mice did not develop hepatic steatosis. However, administration of Ildr2 shRNA to Ildr2 knock-out mice did cause hepatic steatosis, indicating that the Ildr2 shRNA had apparent “off-target” effects on gene(s) other than Ildr2. RNA sequencing and BLAST sequence alignment revealed Dgka as a candidate gene mediating these “off-target” effects. Ildr2 shRNA is 63% homologous to the Dgka gene, and Dgka expression decreased only in mice displaying hepatic steatosis. Dgka encodes diacylglycerol kinase (DGK) alpha, one of a family of DGKs which convert diacylglycerides to phosphatidic acid for second messenger signaling. Dgka knockdown mice would be expected to accumulate diacylglyceride, contributing to the observed hepatic steatosis. We conclude that ILDR2 plays a negligible role in hepatic steatosis. Rather, hepatic steatosis observed previously in Ildr2 knockdown mice was likely due to shRNA targeting of Dgka and/or other “off-target” genes. We propose that the gene candidates identified in this follow-up study may lead to identification of novel regulators of hepatic lipid metabolism.
  • Supichaya Boonvisut, Ken Yoshida, Kazuhiro Nakayama, Kazuhisa Watanabe, Hiroshi Miyashita, Sadahiko Iwamoto
    LIPIDS IN HEALTH AND DISEASE 16 1 183  2017年09月 [査読有り][通常論文]
     
    Background: Non-alcoholic fatty liver disease (NAFLD) is a disorder characterized by excessive fat deposits in hepatocytes without excessive alcohol intake. NAFLD is influenced by genetic factors, and the heritability has been estimated at 0.35 to 0.6 by twin studies. We explored rare variants in known NAFLD-associated genes to investigate whether these rare variants are involved in the susceptibility to NAFLD. Methods: The target genes for re-sequencing were PNPLA3, TM6SF2, and MTTP. All exons of these three genes were amplified from a discovery panel of 950 Japanese males, and the identified rare variants were further tested for genetic association in 3014 individuals from the Japanese general population and for in vitro functional evaluation. Results: Target re-sequencing analysis using next-generation sequencing identified 29 rare variants in 65 Japanese males (6.84%), 12 of which were newly identified base substitutions. A splicing mutation in TM6SF2 that resulted in deletion of 31 amino acids was identified in an NAFLD case. Among eight genotyped rare single-nucleotide polymorphisms (SNPs; minor allele frequency < 0.02), rs143392071 (Tyr220Cys, PNPLA3) significantly increased (odds ratio = 3.52, P = 0.008) and rs756998920 (Val42Ile, MTTP) significantly decreased (odds ratio = 0.03, P = 0.019) the NAFLD risk. Functional assays showed that these two SNPs disrupted protein functions and supported the genetic association. Conclusion: Collectively, 1.79% of individuals in our studied population were estimated carriers of rare variants that are potentially associated with NAFLD.
  • Kazuhiro Nakayama, Jun Ohashi, Kazuhisa Watanabe, Lkagvasuren Munkhtulga, Sadahiko Iwamoto
    MOLECULAR BIOLOGY AND EVOLUTION 34 8 1936 - 1946 2017年08月 [査読有り][通常論文]
     
    Mongols, the founders of the largest continental empire in history, successfully adapted to the harsh environments of Inner Asia through nomadic pastoralism. Considerable interest exists in ascertaining whether genetic adaptation also contributed to the Mongols' success, and dissecting the genome diversity of present-day populations in Mongolia can help address this question. To this end, we determined the genotypes of nearly 2.4 million single nucleotide polymorphisms (SNPs) of 96 unrelated Mongolian individuals in Ulaanbaatar city, and performed genome-wide scans for population-specific positive selection. We discovered signatures of Mongolian-specific positive selection at the chromosomal region 3p12.1, in which hits in genome-wide association studies were reported for medical and biological traits related to energy metabolism and reproduction. The top SNP, rs117799927, showed a distinctive geographic distribution: the frequency of the derived allele, rs117799927 G, was extremely low among worldwide populations (0.005) but exceptionally high in Mongolians (0.247). Approximate Bayesian computation-based age estimation showed that the rs117799927 G allele emerged or positive selection began to operate 50 generations before the present, near the age of the climate anomaly named Late Antique Little Ice Age. Furthermore, rs117799927 showed significant associations with multiple adiposity-related traits in Mongolians and allelic difference in enhancer activity in cells of adipocyte lineage, suggesting that positive selection at 3p12.1 might be related to adaptation in the energy metabolism system. These findings provide novel evidence for a very recent positive-selection event in Homo sapiens and offer insights into the roles of genes in 3p12.1 in the adaptive evolution of our species.
  • Kazuhiro Nakayama, Shinichi Saito, Kazuhisa Watanabe, Hiroshi Miyashita, Fuyuhiko Nishijima, Yoshie Kamo, Koji Tada, Satoshi Ishizuka, Toshimitsu Niwa, Sadahiko Iwamoto, Hidehisa Shimizu
    BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 81 6 1120 - 1124 2017年 [査読有り][通常論文]
     
    The function of aryl hydrocarbon receptor repressor (AHRR) in the kidney is unclear. The present study investigated associations between AHRR Pro189Ala polymorphism and estimated glomerular filtration rates (eGFR), serum creatinine, and hemoglobin levels in 2775 Japanese adults without diabetes. In addition, we examined whether AHRR expression levels in the kidney of control and chronic kidney disease (CKD) rats were changed. Multiple linear regression analyses showed that carriers of the Ala allele had increased eGFR and lower concentrations of serum creatinine and hemoglobin (p < 0.05). Immunohistochemical analysis showed that the expression of AHRR was upregulated in the kidneys of rats with CKD. These findings suggest that AHRR plays distinct roles in kidney functions and hemoglobin values. The effects of the AHRR polymorphism might be intensified in the kidneys of patients with CKD.
  • Michael V. Morabito, Yann Ravussin, Bridget R. Mueller, Alicja A. Skowronski, Kazuhisa Watanabe, Kylie S. Foo, Samuel X. Lee, Anders Lehmann, Stephan Hjorth, Lori M. Zeltser, Charles A. LeDuc, Rudolph L. Leibel
    PLOS ONE 12 1 e0168226  2017年01月 [査読有り][通常論文]
     
    Diet-induced obesity (DIO) resulting from consumption of a high fat diet (HFD) attenuates normal neuronal responses to leptin and may contribute to the metabolic defense of an acquired higher body weight in humans; the molecular bases for the persistence of this defense are unknown. We measured the responses of 23 brain regions to exogenous leptin in 4 different groups of weight-and/or diet-perturbed mice. Responses to leptin were assessed by quantifying pSTAT3 levels in brain nuclei 30 minutes following 3 mg/kg intraperitoneal leptin. HFD attenuated leptin sensing throughout the brain, but weight loss did not restore central leptin signaling to control levels in several brain regions important in energy homeostasis, including the arcuate and dorsomedial hypothalamic nuclei. Effects of diet on leptin signaling varied by brain region, with results dependent on the method of weight loss (restriction of calories of HFD, ad lib intake of standard mouse chow). High fat diet attenuates leptin signaling throughout the brain, but some brain regions maintain their ability to sense leptin. Weight loss restores leptin sensing to some degree in most (but not all) brain regions, while other brain regions display hypersensitivity to leptin following weight loss. Normal leptin sensing was restored in several brain regions, with the pattern of restoration dependent on the method of weight loss.
  • Kazuhisa Watanabe, Kazuhiro Nakayama, Satoshi Ohta, Kenji Tago, Supichaya Boonvisut, Elizabeth J. Millings, Stuart G. Fischer, Charles A. LeDuc, Rudolph L. Leibel, Sadahiko Iwamoto
    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 477 4 712 - 716 2016年09月 [査読有り][通常論文]
     
    A diabetes susceptibility gene, immunoglobulin-like domain containing receptor 2 (Ildr2), encodes a transmembrane protein localized to the endoplasmic reticulum membrane that is closely related to hepatic lipid metabolism. The livers of ob/ob mice in which Ildr2 is transiently overexpressed are relieved of hepatic steatosis. However, the molecular mechanisms through which ILDR2 affects these changes in hepatic lipid metabolism remain unknown. This study aimed to identify ILDR2-interacting proteins to further elucidate the molecular mechanisms underlying the role of ILDR2 in lipid homeostasis. We purified ILDR2-containing protein complexes using tandem affinity purification tagging and identified ZNF70, a member of the Kruppel C2H2-type zinc finger protein family, as a novel ILDR2-interacting protein. We demonstrated that ZNF70 interacts with ZFP64 and activates HES1 transcription by binding to the HES1 promoter. In addition, HES1 gene expression is increased in ILDR2-knockdown HepG2 cells, in which ZNF70 is translocated from the cytoplasm to the nucleus, suggesting that ZNF70 migration to the nucleus after dissociating from the ILDR2-ZNF70 complex activates HES1 transcription. These results support a novel link between ILDR2 and HES1 gene expression and suggest that ILDR2 is involved in a novel pathway in hepatic steatosis. (C) 2016 Elsevier Inc. All rights reserved.
  • Supichaya Boonvisut, Kazuhiro Nakayama, Saho Makishima, Kazuhisa Watanabe, Hiroshi Miyashita, Munkhtulga Lkhagvasuren, Yasuo Kagawa, Sadahiko Iwamoto
    LIPIDS IN HEALTH AND DISEASE 15 8  2016年01月 [査読有り][通常論文]
     
    Background: The Neurocan-cartilage intermediate layer protein 2 (NCAN-CILP2) region forms a tight linkage disequilibrium (LD) block and is associated with plasma lipid levels and non-alcoholic fatty liver disease (NAFLD) in individuals of European descent but not in the Malay and Japanese ethnic groups. Recent genome-wide resequence studies identified a missense single-nucleotide polymorphism (SNP) (rs58542926) of the transmembrane 6 superfamily member 2 (TM6SF2) gene in the NCAN-CILP2 region related to hepatic triglyceride content. This study aims to analyze the influences of SNPs in this region on NAFLD and plasma lipid levels in the Asian and Pacific ethnic groups and to reveal the reasons behind positive and negative genetic associations dependent on ethnicity. Methods: Samples and characteristic data were collected from 3,013 Japanese, 119 Palauan, 947 Mongolian, 212 Thai and 401 Chinese people. Hepatic sonography data was obtained from the Japanese individuals. Genotyping data of five SNPs, rs58542926, rs735273, rs1009136, rs1858999, and rs16996148, were used to verify the effect on serum lipid levels by multiple linear regression, and the association with NAFLD in the Japanese population was examined by logistic regression analysis. Results: rs58542926 showed significant association with the plasma triglyceride (TG) level in Japanese (P = 0.0009, effect size = 9.5 (+/- 3.25) mg/dl/allele) and Thai (P = 0.0008, effect size = 31.6 (+/- 11.7) mg/dl/allele) study subjects. In Mongolian individuals, there was a significant association of rs58542926 with total cholesterol level (P = 0.0003, 11.7 (+/- 3.2) mg/dl/allele) but not with TG level. In multiple comparisons in Chinese individuals, rs58542926 was weakly (P = 0.022) associated with TG levels, although the threshold for statistical significance was not reached. In Palauan individuals, there was no significant association with the studied SNPs. rs58542926 also showed significant association with Japanese NAFLD. The minor allele (t) increased NAFLD risk (OR 1.682, 95 % CI 1.289-2.196, p value 0.00013). Conclusion: This study confirmed the genetic association of missense SNP of TM6SF2, rs58542926, with plasma lipid levels in multiple East Asian ethnic groups and with NAFLD in Japanese individuals.
  • Sadahiko Iwamoto, Supichaya Boonvisut, Saho Makishima, Yuumi Ishizuka, Kazuhisa Watanabe, Kazuhiro Nakayama
    BIOCHEMICAL SOCIETY TRANSACTIONS 43 5 1063 - 1068 2015年10月 [査読有り][通常論文]
     
    The plasma concentration of lipids is a heritable risk factor for the development of atherosclerosis and related coronary artery diseases (CAD). Mammalian tribbles homologue 1 (TRIB1) is a human locus, the downstream linkage disequilibrium (LD) block of which affects plasma low-density lipoprotein (LDL)-associated cholesterol, triglyceride (TG) levels and CAD across multiple ethnic groups. In addition, association of TRIB1 with non-alcoholic fatty liver disease (NAFLD) has also been shown. A regulatory sequence that enhances TRIB1 promoter activity was identified in the LD block and the minor allele of a single nt polymorphism (SNP, rs6982502) in this regulatory sequence reduces the activity of the TRIB1 promoter. The minor allele of rs6982502 is a risk allele for increasing plasma lipid levels and NAFLD. Trib1 deficiency increases plasma cholesterol and TGs in mice and overexpression of TRIB1 in mouse liver reduces these factors. Expression of rate-limiting lipogenic enzymes is increased in Trib1-knockout mouse liver and decreased with overexpression. Recently, carbohydrate-responsive element-binding protein (ChREBP) emerged as a novel binding partner of TRIB1. Furthermore, novel binding partner, Sin3A (Swi-independent 3A)-associated protein, 18 kDa, was identified, which activates microsomal TG transfer protein (MTTP) expression by binding with MTTP regulatory elements in co-ordination with mSin3A and TRIB1. Very recently, a small molecular compound that up-regulates TRIB1 expression in HepG2 cells has been discovered. Further exploration of the binding partners of TRIB1 and their involvement in lipid metabolism may aid discovery of novel pharmacological targets for the management of dyslipidaemia and steatosis.
  • Saho Makishima, Supichaya Boonvisut, Yuumi Ishizuka, Kazuhisa Watanabe, Kazuhiro Nakayama, Sadahiko Iwamoto
    JOURNAL OF LIPID RESEARCH 56 6 1145 - 1152 2015年06月 [査読有り][通常論文]
     
    Mammalian tribbles homolog 1 (TRIB1) is a human locus that has been shown to significantly impact plasma lipid levels across several ethnic groups. In addition, the gene has been associated with the occurrence of nonalcoholic fatty liver disease. In the present study, a yeast-two-hybrid system was used to screen for novel molecular targets of TRIB1 binding. Loci corresponding to clones that were positive for TRIB1 binding subsequently were assessed for roles in lipid metabolism in mice using adenoviral constructs to induce knockdown or overexpression. Sin3A-associated protein, 18 kDa (SAP18) was identified as a novel binding partner of TRIB1. Knockdown of the Sap18 in mouse liver decreased plasma lipid levels and increased hepatic lipid levels; SAP18 overexpression showed the opposite effects. Transcriptome analysis of the mouse liver revealed that Sap18 knockdown decreased and SAP18 overexpression increased microsomal TG transfer protein (MTTP) expression levels. Chromatin immunoprecipitation analysis showed that halo-tagged SAP18, halo-tagged TRIB1, and anti-mSin3A antibody enriched precipitates for regulatory sequences of the MTTP gene. Enforced expression of SAP18 enhanced and SAP18 knockdown conversely attenuated the enrichment of MTTP regulatory sequences seen with anti-mSin3A antibody. These studies indicated that SAP18 expression enhanced the recruitment of mSin3A in coordination with TRIB1 to MTTP regulatory elements and increased MTTP expression.
  • Kazuhiro Nakayama, Kazuhisa Watanabe, Supichaya Boonvisut, Saho Makishima, Hiroshi Miyashita, Sadahiko Iwamoto
    AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY 307 11 G1108 - G1114 2014年12月 [査読有り][通常論文]
     
    Animal studies have demonstrated that glucose-dependent insulinotropic polypeptide (GIP) and GIP receptor (GIPR) contribute to the etiology of obesity. In humans, genomewide association studies have identified single nucleotide polymorphisms (SNPs) in the GIPR gene that are strongly associated with body mass index (BMI); however, it is not clear whether genetic variations in the GIP gene are involved in the development of obesity. In the current study, we assessed the impact of GIP SNPs on obesity-related traits in Japanese adults. Six tag SNPs were tested for associations with obesity-related traits in 3,013 individuals. Multiple linear regression analyses showed that rs9904288, located at the 3'-end of GIP, was significantly associated with visceral fat area (VFA). Moreover, rs1390154 and rs4794008 showed significant associations with plasma triglyceride levels and hemoglobin A(lc) levels, respectively. Among the significant SNPs, rs9904288 and rs1390154 were independently linked with SNPs in active enhancers of the duodenum mucosa, the main GIP-secreting tissue. The haplotypes of these two SNPs exhibited stronger associations with VFA. Numbers of VFA-increasing alleles of rs9904288 and BMI-increasing alleles of previously identified GIPR SNPs showed a strong additive effect on VFA, waist circumference, and BMI in the subject population. These novel results support the notion that the GIP-GIPR axis plays a role in the etiology of central obesity in humans, which is characterized by the accumulation of visceral fat.
  • Yann Ravussin, Charles A. LeDue, Kazuhisa Watanabe, Bridget R. Mueller, Alicia Skowronski, Michael Rosenbaum, Rudoph L. Leibel
    MOLECULAR METABOLISM 3 4 432 - 440 2014年07月 [査読有り][通常論文]
     
    Circulating leptin concentrations correlate with fat mass and signal the status of somatic energy stores to the brain. Previous studies suggest that diet-induced elevations of body weight increase body weight "set-point". To assess whether chronic hyperleptinemia is responsible for this shift in defended body weight, we elevated circulating leptin concentrations in lean mice to those comparable to diet-induced obese mice for eighteen weeks. We hypothesized that following cessation of leptin infusion, a higher body weight would be defended. Compared to saline infused controls, leptin-infused mice had elevated circulating leptin concentrations, gained less weight, yet had similar metabolic rates. Following cessation of leptin administration, leptin-infused mice gained some weight yet plateaued at 5-10% below controls. These results suggest that, unlike mice rendered hyperleptinemic by diet-induced weight gain, leptin-infused mice do not subsequently "defend" a higher body weight, suggesting that hyperleptinemia per se does not mimic the CNS consequences of chronic weight gain. (C) 2014 The Authors. Published by Elsevier GmbH.
  • Alicja A. Skowronski, Michael V. Morabito, Bridget R. Mueller, Samuel Lee, Stephan Hjorth, Anders Lehmann, Kazuhisa Watanabe, Lori M. Zeltser, Yann Ravussin, Michael Rosenbaum, Charles A. LeDuc, Rudolph L. Leibel
    OBESITY 22 5 1287 - 1295 2014年05月 [査読有り][通常論文]
     
    Objective: The physiology of the weight-reduced (WR) state suggests that pharmacologic agents affecting energy homeostasis may have greater efficacy in WR individuals. Our aim was to establish a protocol that allows for evaluation of efficacy of weight maintenance agents and to assess the effectiveness of AZD2820, a novel melanocortin 4 receptor (MC4R) agonist in such a paradigm. Methods: MC4R agonist was administered in stratified doses to mice who were either fed high-fat diet ad libitum (AL) throughout the study; or stabilized at a 20% reduced body weight (BW), administered the drug for 4 weeks, and thereafter released from caloric restriction while continuing to receive the drug (WR). Results: After release of WR mice to AL feeding, the high-dose group (53.4 nmol/day) regained 12.4% less BW than their vehicle-treated controls since the beginning of drug treatment. In WR mice, 10.8 nmol/day of the agonist was sufficient to maintain these animals at 95.1% of initial BW versus 53.4 nmol/day required to maintain the BW of AL animals (94.5%). Conclusions: In the WR state, the MC4R agonist was comparably efficacious to a five-fold higher dose in the AL state. This protocol provides a model for evaluating the mechanisms and quantitative efficacy of weight-maintenance strategies and agents.
  • Shang L, Hua H, Foo K, Martinez H, Watanabe K, Zimmer M, Kahler DJ, Freeby M, Chung W, LeDuc C, Goland R, Leibel RL, Egli D
    Diabetes 63 3 923 - 933 3 2014年03月 [査読有り][通常論文]
  • N. Wakae-Takada, S. Xuan, K. Watanabe, P. Meda, R. L. Leibel
    DIABETOLOGIA 56 4 856 - 866 2013年04月 [査読有り][通常論文]
     
    In rodents and humans, the rate of beta cell proliferation declines rapidly after birth; formation of the islets of Langerhans begins perinatally and continues after birth. Here, we tested the hypothesis that increasing levels of E-cadherin during islet formation mediate the decline in beta cell proliferation rate by contributing to a reduction of nuclear beta-catenin and D-cyclins. We examined E-cadherin, nuclear beta-catenin, and D-cyclin levels, as well as cell proliferation during in vitro and in vivo formation of islet cell aggregates, using beta-TC6 cells and transgenic mice with green fluorescent protein (GFP)-labelled beta cells, respectively. We tested the role of E-cadherin using antisense-mediated reductions of E-cadherin in beta-TC6 cells, and mice segregating for a beta cell-specific E-cadherin knockout (Ecad [also known as Cdh1] beta KO). In vitro, pseudo-islets of beta-TC6 cells displayed increased E-cadherin but decreased nuclear beta-catenin and cyclin D2, and reduced rates of cell proliferation, compared with monolayers. Antisense knockdown of E-cadherin increased cell proliferation and levels of cyclins D1 and D2. After birth, beta cells showed increased levels of E-cadherin, but decreased levels of D-cyclin, whereas islets of Ecad beta KO mice showed increased levels of D-cyclins and nuclear beta-catenin, as well as increased beta cell proliferation. These islets were significantly larger than those of control mice and displayed reduced levels of connexin 36. These changes correlated with reduced insulin response to ambient glucose, both in vitro and in vivo. The findings support our hypothesis by indicating an important role of E-cadherin in the control of beta cell mass and function.
  • Watanabe K, Watson E, Cremona ML, Millings EJ, Lefkowitch JH, Fischer SG, LeDuc CA, Leibel RL
    PloS one 8 6 e67234  6 2013年 [査読有り][通常論文]
  • Yann Ravussin, Charles A. LeDuc, Kazuhisa Watanabe, Rudolph L. Leibel
    AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY 303 4 R438 - R448 2012年08月 [査読有り][通常論文]
     
    Ravussin Y, LeDuc CA, Watanabe K, Leibel RL. Effects of ambient temperature on adaptive thermogenesis during maintenance of reduced body weight in mice. Am J Physiol Regul Integr Comp Physiol 303: R438-R448, 2012. First published July 3, 2012; doi:10.1152/ajpregu.00092.2012.-We showed previously that, at ambient room temperature (22 degrees C), mice maintained at 20% below their initial body weight by calorie restriction expend energy at a rate below that which can be accounted for by the decrease of fat and fat-free mass. Food-restricted rodents may become torpid at subthermoneutral temperatures, a possible confounding factor when using mice as human models in obesity research. We examined the bioenergetic, hormonal, and behavioral responses to maintenance of a 20% body weight reduction in singly housed C57BL/6J +/+ and Lep(ob) mice housed at both 22 degrees C and 30 degrees C. Weight-reduced high-fat-fed diet mice (HFD-WR) showed similar quantitative reductions in energy expenditure-adjusted for body mass and composition-at both 22 C and 30 C: -1.4 kcal/24 h and -1.6 kcal/24 h below predicted, respectively, and neither group entered torpor. In contrast, weight-reduced Lep(ob) mice (OB-WR) housed at 22 degrees C became torpid in the late lights-off period (0200-0500) but did not when housed at 30 C. These studies indicate that mice with an intact leptin axis display similar decreases in "absolute" energy expenditure in response to weight reduction at both 22 degrees C and 30 degrees C ambient temperature. More importantly, the "percent" decrease in total energy expenditure observed in the HFD-WR compared with AL mice is much greater at 30 degrees C (-19%) than at 22 degrees C (-10%). Basal energy expenditure demands are similar to 45% lower in mice housed at 30 degrees C vs. 22 degrees C, since the mice housed at thermoneutrality do not allocate extra energy for heat production. The higher total energy expenditure of mice housed at 22 degrees C due to these increased thermogenic demands may mask physiologically relevant changes in energy expenditure showing that ambient temperature must be carefully considered when quantifying energy metabolism in both rodents and humans.
  • Takashi Yamamoto, Kazuhisa Watanabe, Noriyuki Inoue, Yoshimi Nakagawa, Naomi Ishigaki, Takashi Matsuzaka, Yoshinori Takeuchi, Kazuto Kobayashi, Shigeru Yatoh, Akimitsu Takahashi, Hiroaki Suzuki, Naoya Yahagi, Takanari Gotoda, Nobuhiro Yamada, Hitoshi Shimano
    JOURNAL OF LIPID RESEARCH 51 7 1859 - 1870 2010年07月 [査読有り][通常論文]
     
    Sterol-regulatory element binding protein-1c (SREBP-1c) is a transcription factor that controls lipogenesis in the liver. Hepatic SREBP-1c is nutritionally regulated, and its sustained activation causes hepatic steatosis and insulin resistance. Although regulation of SREBP-1c is known to occur at the transcriptional level, the precise mechanism by which insulin signaling activates SREBP-1c promoter remains to be elucidated. Here we show that protein kinase C beta (PKCbeta) is a key mediator of insulin-mediated activation of hepatic SREBP-1c and its target lipogenic genes. Activation of SREBP-1c in the liver of refed mice was suppressed by either adenoviral RNAi-mediated knockdown or dietary administration of a specific inhibitor of protein kinase C beta. The effect of PKCbeta inhibition was cancelled in insulin depletion by streptozotocin (STZ) treatment of mice. Promoter analysis indicated that PKCbeta activates SREBP-1c promoter through replacement of Sp3 by Sp1 for binding to the GC box in the sterol regulatory element (SRE) complex, a key cis-element of SREBP-1c promoter. Knockdown of Sp proteins demonstrated that Sp3 and Sp1 play reciprocally negative and positive roles in nutritional regulation of SREBP-1c, respectively. This new understanding of PKCbeta involvement in nutritional regulation of SREBP-1c activation provides a new aspect of PKCbeta inhibition as a potential therapeutic target for diabetic complications.-Yamamoto, T., K. Watanabe, N. Inoue, Y. Nakagawa, N. Ishigaki, T. Matsuzaka, Y. Takeuchi, K. Kobayashi, S. Yatoh, A. Takahashi, H. Suzuki, N. Yahagi, T. Gotoda, N. Yamada, and H. Shimano. Protein kinase Cbeta mediates hepatic induction of sterol-regulatory element binding protein-1c by insulin. J Lipid Res. 2010. 51: 1859-1870.
  • Hirosuke Danno, Kiyo-aki Ishii, Yoshimi Nakagawa, Motoki Mikami, Takashi Yamamoto, Sachiko Yabe, Mika Furusawa, Shin Kumadaki, Kazuhisa Watanabe, Hidehisa Shimizu, Takashi Matsuzaka, Kazuto Kobayashi, Akimitsu Takahashi, Shigeru Yatoh, Hiroaki Suzuki, Nobuhiro Yamada, Hitoshi Shimano
    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 391 2 1222 - 1227 2010年01月 [査読有り][通常論文]
     
    To elucidate the physiological role of CREBH, the hepatic mRNA and protein levels of CREBH were estimated in various feeding states of wild and obesity mice. In the fast state, the expression of CREBH mRNA and nuclear protein were high and profoundly suppressed by refeeding in the wild-type mice. In ob/ob mice, the refeeding suppression was impaired. The diet studies suggested that CREBH expression was activated by fatty acids. CREBH mRNA levels in the mouse primary hepatocytes were elevated by addition of the palmitate, oleate and eicosapenonate. it was also induced by PPAR alpha agonist and repressed by PPAR alpha antagonist. Luciferase reporter gene assays indicated that the CREBH promoter activity was induced by fatty acids and co-expression of PPAR alpha. Deletion studies identified the PPRE for PPAR alpha activation. Electrophoretic mobility shift assay and chromatin immunoprecipitation (ChIP) assay confirmed that PPAR alpha directly binds to the PPRE. Activation of CREBH at fasting through fatty acids and PPAR alpha suggest that CREBH is involved in nutritional regulation. (C) 2009 Elsevier Inc. All rights reserved.
  • Kazuhisa Watanabe, Fumiki Okamoto, Tomotaka Yokoo, KaorukoTada Iida, Hiroaki Suzuki, Hitoshi Shimano, Tetsuro Oshika, Nobuhiro Yamada, Hideo Toyoshima
    JOURNAL OF ATHEROSCLEROSIS AND THROMBOSIS 16 2 69 - 76 2009年04月 [査読有り][通常論文]
     
    Aim: Neovascularization is an important event in proliferative diabetic retinopathy (PDR), where various secretory proteins including multiple growth factors are considered to be involved in this process. We searched for secretory proteins expressed in a surgical specimen obtained from the eyes of patients with PDR. Methods: We developed the oligo-cap signal sequence trap (SST) strategy which enables us to screen for secretory or membrane proteins from a minimal starting material. Using this method, we were able to screen a cDNA library constructed from a surgical specimen obtained from the eyes of the patients with PDR. Results: Majority of the cloned cDNAs turned out to encode secreted protein acidic and rich in cystein (SPARC), strongly suggesting that SPARC is highly expressed in PDR. Analysis of vitreous fluid from various patients has shown that the concentration of SPARC protein is increased in patients with PDR. Furthermore, subretinal injection of recombinant SPARC adenovirus induced PDR-like changes in the rat eye. Conclusions: Our results strongly suggested that SPARC is involved in the development of diabetic retinopathy (DR).
  • Noriyuki Inoue, Naoya Yahagi, Takashi Yamamoto, Mayumi Ishikawa, Kazuhisa Watanabe, Takashi Matsuzaka, Yoshimi Nakagawa, Yoshinori Takeuchi, Kazuto Kobayashi, Akimitsu Takahashi, Hiroaki Suzuki, Alyssa H. Hasty, Hideo Toyoshima, Nobuhiro Yamada, Hitoshi Shimano
    JOURNAL OF BIOLOGICAL CHEMISTRY 283 30 21220 - 21229 2008年07月 [査読有り][通常論文]
     
    Both adipocyte hyperplasia and hypertrophy are determinant factors for adipocyte differentiation during the development of obesity. p21(WAF1/CIP1), a cyclin-dependent kinase inhibitor, is induced during adipocyte differentiation; however, its precise contribution to this process is unknown. Using both in vitro and in vivo systems, we show that p21 is crucial for maintaining adipocyte hypertrophy and obesity-induced insulin resistance. The absence of p21 in 3T3-L1 fibroblasts by RNA-mediated interference knockdown or in embryonic fibroblasts from p21(-/-) mice impaired adipocyte differentiation, resulting in smaller adipocytes. Despite normal adipose tissue mass on a normal diet, p21(-/-) mice fed high energy diets had reduced adipose tissue mass and adipocyte size accompanied by a marked improvement in insulin sensitivity. Knockdown of p21 in enlarged epididymal fat of diet-induced obese mice and also in fully differentiated 3T3-L1 adipocytes caused vigorous apoptosis by activating p53. Thus, p21 is involved in both adipocyte differentiation and in protecting hypertrophied adipocytes against apoptosis. Via both of these mechanisms, p21 promotes adipose tissue expansion during high fat diet feeding, leading to increased downstream pathophysiological consequences such as insulin resistance.
  • Satoko Ohgaki, Kaoruko lida, Tornotaka Yokoo, Kazutoshi Watanabe, Rurni Kilhara, Hiroaki Suzuki, Hitoshi Shimano, Hideo Toyoshima, Nobuhiro Yamada
    JOURNAL OF ATHEROSCLEROSIS AND THROMBOSIS 14 4 179 - 184 2007年08月 [査読有り][通常論文]
     
    Aim: A number of adipocytokines have been suggested to be involved in the disruption of glucose metabolism, and also in the development of various diabetic complications. We attempted to identify and analyze additional adipocytokines, to better understanding the roles of adipocytes and adipocytokines. Methods: An oligo-capping signal sequence trap, developed in our laboratory for screening the cDNAs of secretory proteins, was used to sreen cDNAs expressed in mouse white adipose tissue. Profiles of the genes identified in mice and cultured cells were further investigated by northern blotting and luciferase assay. Results: A cDNA fragment of interferon-stimulated gene 12b (ISG12b) was obtained in the search. A northern blot analysis revealed ISG12b to be highly expressed in white adipose tissue. Interferon a (IFN alpha) was shown to induce ISG12b expression in the adipose tissue of BL6 mice in vivo, and also in a 3T3-L1 preadipocyte cell line in vitro. The level of ISG12b was higher in mature adipocytes than in preadipocytes. A promoter analysis demonstrated that the 369bp upstream from the transcription initiation site of ISG12b mRNA contain strong promoter activity, and the interferon-stimulated response elements (ISREs) were not present within the 5593bp upstream region. Conclusion: ISG12b is an additional candidate for a adipocytokine induced to express in adipose tissue by interferon.
  • YH Wang, H Suzuki, T Yokoo, K Tada-Iida, R Kihara, M Miura, K Watanabe, H Sone, H Shimano, H Toyoshima, N Yamada
    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 324 3 1053 - 1058 2004年11月 [査読有り][通常論文]
     
    Rho family GTPases regulate multiple cellular processes through their downstream effectors, where their activities are stimulated by the guanine nucleotide exchange factors. Here, we report a new member of RhoGEF, WGEF, which has the classical structure of DH-PH domain and a C-terminal SH3 domain. WGEF was shown to activate RhoA, Cdc42, and Racl by pulldown assay, and forced expression of WGEF resulted in marked rearrangement of the actin cytoskeleton, which is typically seen by the activation of RhoA, Cdc42, and Racl. WGEF was highly expressed in intestine and also in liver, heart and kidney, which may suggest the involvement of WGEF in the development and functions of these organs. The expression pattern may also suggest the possible importance of WGEF in the understanding of diseases based on metabolic disorder. (C) 2004 Elsevier Inc. All rights reserved.

受賞

  • 2011年11月 Columbia University Naomi Berrie Fellow Award
     
    受賞者: 渡邉 和寿
  • 2010年 公益財団法人 鈴木万平糖尿病財団 平成22年度 海外留学助成
     
    受賞者: 渡邉 和寿

共同研究・競争的資金等の研究課題

  • 小胞体ストレスと脂肪肝発症を仲介する小胞体膜タンパク質ILDR2の分子機構の解明
    文部科学省:科学研究費補助金(若手(B))
    研究期間 : 2017年04月 -2019年03月 
    代表者 : 渡邉 和寿
  • 小胞体ストレスと脂肪肝に関連する新規小胞体局在膜タンパク質ILDR2の機能解析
    文部科学省:科学研究費補助金(若手(B))
    研究期間 : 2015年04月 -2017年03月 
    代表者 : 渡邉和寿

担当経験のある科目

  • 生化学マロニエ医療福祉専門学校
  • 人類遺伝学自治医科大学医学部


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