Updated on 2022/11/26

写真a

 
CHIBA, Takuya
 
Scopus Paper Info  
Paper Count: 0  Citation Count: 0  h-index: 11

Citation count denotes the number of citations in papers published for a particular year.

Affiliation
Faculty of Human Sciences, School of Human Sciences
Job title
Professor

Concurrent Post

  • Affiliated organization   Global Education Center

  • Faculty of Human Sciences   Graduate School of Human Sciences

Education

  •  
    -
    2001

    Kyoto University   Graduate School, Division of Medicine  

Degree

  • 博士(医学)

Research Experience

  • 2014.04
    -
    Now

    東京都健康長寿医療センター研究所   協力研究員

  • 2014.04
    -
    Now

    Waseda University   Faculty of Human Sciences

  • 2012.04
    -
    2014.03

    Waseda University   Faculty of Human Sciences

  • 2009.01
    -
    2012.03

    Nagasaki University   Graduate School of Biomedical Sciences

  • 2007.04
    -
    2008.12

    Nagasaki University   Graduate School of Biomedical Sciences

  • 2002.04
    -
    2007.03

    Nagasaki University   Graduate School of Biomedical Sciences

  • 2003.08
    -
    2005.04

    The Scripps Research Institute, Reaearch associate

  • 2001.04
    -
    2002.03

    Nagasaki University   School of Medicine

▼display all

Professional Memberships

  •  
     
     

    日本神経化学会

  •  
     
     

    日本分子生物学会

  •  
     
     

    日本基礎老化学会

  •  
     
     

    老化促進モデルマウス研究協議会

  •  
     
     

    日本抗加齢医学会

  •  
     
     

    日本病理学会

▼display all

 

Research Areas

  • Medical biochemistry

  • Experimental pathology

  • Physiology

  • Family and consumer sciences, and culture and living

Research Interests

  • 創薬

  • 神経ペプチド

  • インスリンシグナル

  • 細胞老化

  • 細胞周期

  • ゲノム編集

  • 発がん

  • DNA損傷

  • 早老症

  • 生活習慣病

  • 老化

▼display all

Papers

  • カロリー制限の抗老化作用とヒトへの応用に向けた最近の知見

    吉井幸, 近藤嘉高, 千葉卓哉

    食と医療   ( 18 ) 33 - 39  2021.07

  • A Comparison of Gene Expression Profiles of Rat Tissues after Mild and Short-Term Calorie Restrictions

    Kenji Saito, Maiko Ito, Takuya Chiba, Huijuan Jia, Hisanori Kato

    Nutrients   13 ( 7 ) 2277 - 2277  2021.06  [Refereed]

     View Summary

    Many studies have shown the beneficial effects of calorie restriction (CR) on rodents’ aging; however, the molecular mechanism explaining these beneficial effects is still not fully understood. Previously, we conducted transcriptomic analysis on rat liver with short-term and mild-to-moderate CR to elucidate its early response to such diet. Here, we expanded transcriptome analysis to muscle, adipose tissue, intestine, and brain and compared the gene expression profiles of these multiple organs and of our previous dataset. Several altered gene expressions were found, some of which known to be related to CR. Notably, the commonly regulated genes by CR include nicotinamide phosphoribosyltransferase and heat shock protein 90, which are involved in declining the aging process and thus potential therapeutic targets for aging-related diseases. The data obtained here provide information on early response markers and key mediators of the CR-induced delay in aging as well as on age-associated pathological changes in mammals.

    DOI

    Scopus

    3
    Citation
    (Scopus)
  • PIF1 helicase promotes break‐induced replication in mammalian cells

    Shibo Li, Hailong Wang, Sanaa Jehi, Jun Li, Shuo Liu, Zi Wang, Lan Truong, Takuya Chiba, Zefeng Wang, Xiaohua Wu

    The EMBO Journal   40 ( 8 )  2021.04

    DOI

    Scopus

    25
    Citation
    (Scopus)
  • Taurine Improves Lipid Metabolism and Increases Resistance to Oxidative Stress

    Zi WANG, Yoshihisa OHATA, Yukari WATANABE, Yiwen YUAN, Yuki YOSHII, Yoshitaka KONDO, Shoko NISHIZONO, Takuya CHIBA

    Journal of Nutritional Science and Vitaminology   66 ( 4 ) 347 - 356  2020.08  [Refereed]  [Domestic journal]

     View Summary

    Calorie restriction (CR) by 30-40% decreases morbidity of age-related diseases and prolongs the lifespan of various laboratory animal species. Taurine (2-aminoethanesulfonic acid) is an important nutrient for lipid metabolism as it conjugates bile acids. Here, we investigated how taurine supplementation induces effects similar to the CR beneficial effects. Sprague Dawley rats were fed a diet containing different taurine concentrations (0, 0.5, 1.0, 3.0, 5.0%) to analyze the effects on growth, blood, and hepatic parameters. Rats fed a 5% taurine-supplemented diet showed a significant decrease in visceral fat weight, compared with control rats. Moreover, there were significant decreases in the serum total cholesterol, hepatic cholesterol and triglyceride concentrations in the taurine-supplemented groups compared with the control group in a dose-dependent manner. These results were associated with decreased mRNA expression of fatty acid synthase, and increased mRNA expression of carnitine palmitoyltransferase 1α. C57BL/6 mice were fed a 5.0% taurine-supplemented diet, and their response to 3-nitropropionic acid-induced oxidative stress was analyzed. The rate of weight loss due to oxidative stress decreased and the survival rate significantly increased in the taurine-supplemented groups compared with the control group. Finally, cells were treated with 100 μM taurine and their resistance to UV-induced oxidative stress was analyzed. We found that the p53-Chk1 pathway was less activated in taurine-treated cells compared with control cells. Furthermore, damage to cells evaluated by oxidative stress indicators revealed a reduction in oxidative damage with taurine treatment. These findings suggest that taurine partially acts as a CR mimetic.

    DOI PubMed

    Scopus

    7
    Citation
    (Scopus)
  • 食から健康寿命の延伸を目指す介入法の分子基盤:カロリー制限研究から得られた成果を中心として

    千葉卓哉近, 藤嘉高

    食品と容器   61 ( 11 ) 711 - 717  2020

  • カロリー制限による抗老化機構の解明とその制御物質の探索

    近藤嘉高, 伊藤麻衣子, 千葉卓哉

    医学のあゆみ   274 ( 3 ) 291 - 298  2020

  • Effects of rikkunshito supplementation on resistance to oxidative stress and lifespan in mice

    Wang Z, Komatsu T, Ohata Y, Watanabe Y, Yuan Y, Yoshii Y, Park S, Mori R, Satou M, Kondo Y, Shimokawa I, Chiba T

    Geriatr Gerontol Int   20 ( 3 ) 238 - 247  2020  [Refereed]  [Domestic journal]

     View Summary

    AIM: Caloric restriction (CR), which limits the caloric intake to 60-70% of ad libitum (AL) amounts in various experimental animals, delays aging and extends the lifespan. We previously showed that neuropeptide Y (NPY), an appetite-stimulating peptide, is essential for the anti-oxidative and life-extending effects of CR. Here, we investigated whether a Japanese traditional herbal medicine, rikkunshito (RKT), which induces NPY activation, has CR-like life-extending effects. METHODS: First, we evaluated the life-extending activity of RKT by examining the effect of long-term RKT administration on wild-type and NPY knockout mice. Furthermore, we tested whether RKT enhances CR-mediated beneficial effects under AL conditions with a normal diet and under mild CR conditions with a high-fat diet. We then used 3-nitropropionic acid or doxorubicin to induce oxidative stress, and analyzed the differences in survival rate, weight loss, gene expression and cellular oxidative damage among groups. RESULTS: RKT administration did not extend the lifespan of wild-type or NPY knockout mice. In the oxidative stress models, RKT treatment upregulated anti-oxidative gene expression in the liver. Furthermore, RKT administration reduced the oxidative damage in the liver compared to the CR conditions alone. However, on induction of oxidative stress by 3-nitropropionic acid or doxorubicin, RKT administration did not affect the survival rate. CONCLUSIONS: These results show that RKT administration only partially mimics the effects of CR at the cellular level, but not at the organismal level to increase the lifespan of mice. Geriatr Gerontol Int 2019; ••: ••-••.

    DOI PubMed

    Scopus

  • ERCC1/XPF Is Important for Repair of DNA Double-Strand Breaks Containing Secondary Structures

    Shibo Li, Hongyan Lu, Zi Wang, Qing Hu, Hongjun Wang, Rong Xiang, Takuya Chiba, Xiaohua Wu

    iScience   16   63 - 78  2019.06  [Refereed]

    DOI

    Scopus

    19
    Citation
    (Scopus)
  • DNA polymerase θ (POLQ) is important for repair of DNA double-strand breaks caused by fork collapse

    Zi Wang, Yadong Song, Shibo Li, Sunil Kurian, Rong Xiang, Takuya Chiba, Xiaohua Wu

    Journal of Biological Chemistry   294 ( 11 ) 3909 - 3919  2019.03  [Refereed]

    DOI

  • Mechanisms of action of compounds that mimic beneficial effects of calorie restriction such as lifespan extension: Is taurine a promising candidate?

    Nishizono S, Wang Z, Watanabe Y, Ohata Y, Chiba T

    J Phys Fitness Sports Med   6 ( 4 ) 201 - 207  2017  [Refereed]

  • The life-extending effect of dietary restriction requires Foxo3 in mice

    Isao Shimokawa, Toshimitsu Komatsu, Nobutaka Hayashi, Sang-Eun Kim, Takuya Kawata, Seongjoon Park, Hiroko Hayashi, Haruyoshi Yamaza, Takuya Chiba, Ryoichi Mori

    AGING CELL   14 ( 4 ) 707 - 709  2015.08  [Refereed]

     View Summary

    Forkhead box O (Foxo) transcription factors may be involved in the salutary effect of dietary restriction (DR). This study examined the role of Foxo3 in lifespan extension and cancer suppression in DR mice. Wild-type (WT) and Foxo3-knockout heterozygous ((+/-)) and homozygous ((-/-)) mice were subjected to a 30% DR regimen initiated at 12weeks of age. Control mice were fed adlibitum (AL) throughout the study. In contrast to WT mice, DR did not significantly extend the lifespan of Foxo3(+/-) or Foxo3(-/-) mice. However, DR reduced the prevalence of tumors at death in WT, Foxo3(+/-), and Foxo3(-/-) mice. These results indicate the necessity of Foxo3 for lifespan extension but not cancer suppression by DR. The findings in Foxo3(+/-) mice contrast with those in Foxo1(+/-) mice reported previously by our laboratory suggest differential regulation of cancer and lifespan by DR via Foxo1 and Foxo3.

    DOI

  • Upregulation of cytochrome c oxidase subunit 6b1 (Cox6b1) and formation of mitochondrial supercomplexes: implication of Cox6b1 in the effect of calorie restriction

    Sang-Eun Kim, Ryoichi Mori, Toshimitsu Komatsu, Takuya Chiba, Hiroko Hayashi, Seongjoon Park, Michiru D. Sugawa, Norbert A. Dencher, Isao Shimokawa

    AGE   37 ( 3 ) 9787 - 9787  2015.06  [Refereed]  [International journal]

     View Summary

    Calorie restriction (CR), a non-genetic intervention that promotes longevity in animals, may exert anti-aging effects by modulating mitochondrial function. Based on our prior mitochondrial proteome analysis, we focused on the potential roles of cytochrome c oxidase (Cox or Complex IV) subunit 6b1 on formation of mitochondrial supercomplexes comprised of Complex I, III, and IV. Blue native polyacrylamide gel electrophoresis followed by immunoblotting showed that the amount of Cox6b1 and the proportion of high molecular weight supercomplexes (SCs) comprised of Complexes I, III, and IV were increased in the liver of mice subjected to 30 % CR, compared with the liver of mice fed ad libitum. In in vitro experiments, in Cox6b1-overexpressing NIH3T3 (Cox6b1-3T3) cells, Cox6b1 was increased in the SC, III2IV1, and III2IV2 complexes and Cox was concomitantly recruited abundantly into the SC, compared with control (Con)-3T3 cells. The proportions of III2IV1, and III2IV2, relative to IV monomer were also increased in Cox6b1-3T3 cells. Cox6b1-3T3 cells showed increased oxygen consumption rates, Cox activity, and intracellular ATP concentrations, indicating enhanced mitochondrial respiration, compared with Con-3T3 cells. Despite the increased basal level of mitochondrial reactive oxygen species (ROS), cell viability after inducing oxidative stress was greater in Cox6b1-3T3 cells than in Con-3T3 cells, probably because of prompt activation of protective mechanisms, such as nuclear translocation of nuclear factor E2-related factor-2. These in vivo and in vitro studies show that Cox6b1 is involved in regulation of mitochondrial function by promoting the formation of SC, suggesting that Cox6b1 contributes to the anti-aging effects of CR.

    DOI PubMed

    Scopus

    19
    Citation
    (Scopus)
  • Overexpression of the adiponectin gene mimics the metabolic and stress resistance effects of calorie restriction, but not the anti-tumor effect

    Ryotaro Kamohara, Haruyoshi Yamaza, Tomoshi Tsuchiya, Toshimitsu Komatsu, Seongjoon Park, Hiroko Hayashi, Takuya Chiba, Ryoichi Mori, Shuichi Otabe, Kentaro Yamada, Takeshi Nagayasu, Isao Shimokawa

    EXPERIMENTAL GERONTOLOGY   64   46 - 54  2015.04  [Refereed]

     View Summary

    Adiponectin (Adipoq), a peptide hormone secreted from the white adipose tissue, may play a role in the anti-aging and/or anti-tumor effects of calorie restriction (CR). We analyzed metabolic traits in Adipoq gene-overexpressing mice fed ad libitumwith a regular diet (RD) or a high-fat diet (HFD), or fed 30% CR of RD initiated at 12weeks of age. Adipoq-RD and -HFDmice at 6 months of age showed reduced blood glucose and insulin concentrations, and thus increased insulin sensitivity, compared with WT mice fed a RD or a HFD. In the epididymal white adipose tissue in Adipoq mice, senescence-like changes such as upregulation of p53 protein and of biomarkers of inflammation, Cd68 and Ccl2 mRNA, were ameliorated compared with WT-RD and WT-HFD mouse tissues. Resistance to stress induced by lipopolysaccharide was also strengthened in Adipoq mice compared with WT mice. These metabolic changes and stress resistance were also noted in the WT-CR mice, suggesting that Adipoq plays a part in the effect of CR. In contrast, in an allograft tumor growth model, tumor growth was not inhibited in Adipoq mice. The present findings suggest that Adipoq plays a part in the anti-aging, but not in the anti-tumor, effects of CR. (C) 2015 Elsevier Inc. All rights reserved.

    DOI

    Scopus

    2
    Citation
    (Scopus)
  • Chronological analysis of caloric restriction-induced alteration of fatty acid biosynthesis in white adipose tissue of rats.

    Naoyuki Okita, Takuro Tsuchiya, Mayumi Fukushima, Kaho Itakura, Keiko Yuguchi, Takumi Narita, Yukari Hashizume, Yuka Sudo, Takuya Chiba, Isao Shimokawa, Yoshikazu Higami

    Experimental gerontology   63   59 - 66  2015.03  [Refereed]  [International journal]

     View Summary

    The beneficial actions of caloric restriction (CR) could be mediated in part by metabolic remodeling of white adipose tissue (WAT). Recently, we suggested that CR for 6 months increased the expressions of proteins involved in de novo fatty acid (FA) biosynthesis in WAT of 9-month-old rats. Herein, we compared the CR-induced chronological alterations of the expression of mRNAs and/or proteins involved in FA biosynthesis in the WAT and liver of rats subjected to CR starting from 3 months of age and their age-matched controls fed ad libitum. The findings suggested that CR was more effective on FA biosynthesis in WAT than in liver. In WAT, CR markedly increased the expressions of mRNAs and/or proteins involved in FA biosynthesis, including sterol regulatory element-binding protein 1c (SREBP1c), a master transcriptional regulator of FA biosynthesis, throughout the experimental period. Interestingly, the CR-enhanced upregulation was temporally attenuated at 5 months of age. CR markedly increased the nuclear phosphorylated form of Akt only at 3.5 months of age. In contrast, CR significantly reduced the expression of leptin at 9 months of age. The CR-induced upregulation was not observed in obese fa/fa Zucker rats homozygous for nonfunctional leptin receptor. Collectively, these data indicate that the V-shaped chronological alterations in WAT are regulated via SREBP1c, which is probably activated by CR duration-dependent modulation of both insulin and leptin signaling.

    DOI PubMed

    Scopus

    12
    Citation
    (Scopus)
  • NPY antagonism reduces adiposity and attenuates age-related imbalance of adipose tissue metabolism

    Seongjoon Park, Chika Fujishita, Toshimitsu Komatsu, Sang Eun Kim, Takuya Chiba, Ryoichi Mori, Isao Shimokawa

    FASEB JOURNAL   28 ( 12 ) 5337 - 5348  2014.12  [Refereed]

     View Summary

    An orexigenic hormone, neuropeptide Y (NPY), plays a role not only in the hypothalamic regulation of appetite, but also in the peripheral regulation of lipid metabolism. However, the intracellular mechanisms triggered by NPY to regulate lipid metabolism are poorly understood. Here we report that NPY deficiency reduces white adipose tissue (WAT) mass and ameliorates the age-related imbalance of adipose tissue metabolism in mice. Gene expression involved in adipogenesis/lipogenesis was found to decrease, whereas proteins involved in lipolysis increased in gonadal WAT (gWAT) of NPY-knockout mice. These changes were associated with an activated SIRT1- and PPAR gamma-mediated pathway. Moreover, the age-related decrease of de novo lipogenesis in gWAT and thermogenesis in inguinal WAT was inhibited by NPY deficiency. Further analysis using 3T3-L1 cells showed that NPY inhibited lipolysis through the Y1 receptor and enhanced lipogenesis following a reduction in cAMP response element-binding protein (CREB) and SIRT1 protein expression. Therefore, NPY appears to act as a key regulator of adipose tissue metabolism via the CREB-SIRT1 signaling pathway. Taken together, NPY deficiency reduces adiposity and ameliorates the age-related imbalance of adipose tissue metabolism, suggesting that antagonism of NPY may be a promising target for drug development to prevent age-related metabolic diseases.

    DOI

    Scopus

    29
    Citation
    (Scopus)
  • A key role for neuropeptide Y in lifespan extension and cancer suppression via dietary restriction

    Takuya Chiba, Yukari Tamashiro, Daeui Park, Tatsuya Kusudo, Ryoko Fujie, Toshimitsu Komatsu, Sang Eun Kim, Seongjoon Park, Hiroko Hayashi, Ryoichi Mori, Hitoshi Yamashita, Hae Young Chung, Isao Shimokawa

    SCIENTIFIC REPORTS   4   4517 - 4517  2014.03

     View Summary

    Knowledge of genes essential for the life-extending effect of dietary restriction (DR) in mammals is incomplete. In this study, we found that neuropeptide Y (Npy), which mediates physiological adaptations to energy deficits, is an essential link between DR and longevity in mice. The lifespan-prolonging effect of lifelong 30% DR was attenuated in Npy-null mice, as was the effect on the occurrence of spontaneous tumors and oxidative stress responses in comparison to wild-type mice. In contrast, the physiological processes activated during adaptation to DR, including inhibition of anabolic signaling molecules (insulin and insulin-like growth factor-1), modulation of adipokine and corticosterone levels, and preferential fatty acid oxidation, were unaffected by the absence of Npy. These results suggest a key role for Npy in mediating the effects of DR. We also provide evidence that most of the physiological adaptations to DR could be achieved in mice without Npy.

    DOI

    Scopus

    27
    Citation
    (Scopus)
  • Caloric restriction-associated remodeling of rat white adipose tissue: effects on the growth hormone/insulin-like growth factor-1 axis, sterol regulatory element binding protein-1, and macrophage infiltration

    Yoshikazu Chujo, Namiki Fujii, Naoyuki Okita, Tomokazu Konishi, Takumi Narita, Atsushi Yamada, Yushi Haruyama, Kosuke Tashiro, Takuya Chiba, Isao Shimokawa, Yoshikazu Higami

    AGE   35 ( 4 ) 1143 - 1156  2013.08

     View Summary

    The role of the growth hormone (GH)-insulin-like growth factor (IGF)-1 axis in the lifelong caloric restriction (CR)-associated remodeling of white adipose tissue (WAT), adipocyte size, and gene expression profiles was explored in this study. We analyzed the WAT morphology of 6-7-month-old wild-type Wistar rats fed ad libitum (WdAL) or subjected to CR (WdCR), and of heterozygous transgenic dwarf rats bearing an anti-sense GH transgene fed ad libitum (TgAL) or subjected to CR (TgCR). Although less effective in TgAL, the adipocyte size was significantly reduced in WdCR compared with WdAL. This CR effect was blunted in Tg rats. We also used high-density oligonucleotide microarrays to examine the gene expression profile of WAT of WdAL, WdCR, and TgAL rats. The gene expression profile of WdCR, but not TgAL, differed greatly from that of WdAL. The gene clusters with the largest changes induced by CR but not by Tg were genes involved in lipid biosynthesis and inflammation, particularly sterol regulatory element binding proteins (SREBPs)-regulated and macrophage-related genes, respectively. Real-time reverse-transcription polymerase chain reaction analysis confirmed that the expression of SREBP-1 and its downstream targets was upregulated, whereas the macrophage-related genes were downregulated in WdCR, but not in TgAL. In addition, CR affected the gene expression profile of Tg rats similarly to wild-type rats. Our findings suggest that CR-associated remodeling of WAT, which involves SREBP-1-mediated transcriptional activation and suppression of macrophage infiltration, is regulated in a GH-IGF-1-independent manner.

    DOI

    Scopus

    25
    Citation
    (Scopus)
  • Food and Longevity Genes

    I. Shimokawa, T. Chiba

    Bioactive Food as Dietary Interventions for the Aging Population     61 - 70  2013  [Refereed]

    DOI

    Scopus

  • Protein Reporter Bioassay Systems for the Phenotypic Screening of Candidate Drugs: A Mouse Platform for Anti-aging Drug Screening

    Chiba T, Tsuchiya T, Mori R, Shimokawa I

    Sensors   12 ( 2 ) 1648 - 1656  2012.12

  • Dbf4 Is Direct Downstream Target of Ataxia Telangiectasia Mutated (ATM) and Ataxia Telangiectasia and Rad3-related (ATR) Protein to Regulate Intra-S-phase Checkpoint

    Alan Yueh-Luen Lee, Takuya Chiba, Lan N. Truong, An Ning Cheng, Johnny Do, Michael Jeffrey Cho, Longchuan Chen, Xiaohua Wu

    JOURNAL OF BIOLOGICAL CHEMISTRY   287 ( 4 ) 2531 - 2543  2012.01

     View Summary

    Dbf4/Cdc7 (Dbf4-dependent kinase (DDK)) is activated at the onset of S-phase, and its kinase activity is required for DNA replication initiation from each origin. We showed that DDK is an important target for the S-phase checkpoint in mammalian cells to suppress replication initiation and to protect replication forks. We demonstrated that ataxia telangiectasia mutated (ATM) and ataxia telangiectasia and Rad3-related (ATR) proteins directly phosphorylate Dbf4 in response to ionizing radiation and replication stress. We identified novel ATM/ATR phosphorylation sites on Dbf4 and showed that ATM/ATR-mediated phosphorylation of Dbf4 is critical for the intra-S-phase checkpoint to inhibit DNA replication. The kinase activity of DDK, which is not suppressed upon DNA damage, is required for fork protection under replication stress. We further demonstrated that ATM/ATR-mediated phosphorylation of Dbf4 is important for preventing DNA rereplication upon loss of replication licensing through the activation of the S-phase checkpoint. These studies indicate that DDK is a direct substrate of ATM and ATR to mediate the intra-S-phase checkpoint in mammalian cells.

    DOI

    Scopus

    35
    Citation
    (Scopus)
  • Release of TNF-alpha from macrophages is mediated by small GTPase Rab37

    Ryoichi Mori, Kazuya Ikematsu, Tetsuya Kitaguchi, Sang E. Kim, Momoko Okamoto, Takuya Chiba, Atsushi Miyawaki, Isao Shimokawa, Takashi Tsuboi

    EUROPEAN JOURNAL OF IMMUNOLOGY   41 ( 11 ) 3230 - 3239  2011.11

     View Summary

    Activated macrophages at wound sites release many cytokines which positively affect skin wound healing. However, the molecular mechanisms controlling cytokine secretion from macrophages have not been elucidated. In the present study, we performed an RT-PCR analysis and found that 19 small GTPase Rab isoforms were expressed at skin wound sites, with six of them (i.e. Rab3B, Rab27B, Rab30, Rab33A, Rab37, and Rab40C) being upregulated during the inflammation and proliferation/migration phase of skin repair. We also found that gene expression of Rab37 in murine primary and RAW264.7 macrophages was significantly induced after stimulation with LPS. Overexpression of wild type and constitutively active Rab37 in RAW264.7 cells significantly increased TNF-alpha secretion, whereas knockdown of Rab37 by siRNA significantly decreased it. We also identified 29 putative Rab37-interacting proteins, including the membrane fusion regulating Munc13-1, using liquid chromatography/linear ion trap mass spectrometry (LC-MS/MS). Immunocytochemical analysis further revealed that TNF-alpha-containing vesicles were colocalized with both Rab37 and Munc13-1 in activated macrophages. Knockdown of Munc13-1 by siRNA significantly decreased TNF-alpha secretion. Taken together, these findings demonstrate that Rab37 interacts with Munc13-1 to control TNF-alpha secretion from activated macrophages.

    DOI

    Scopus

    34
    Citation
    (Scopus)
  • Down-regulation of hepatic AMP-activated protein kinase and up-regulation of CREB coactivator CRTC2 for gluconeogenesis under calorie-restricted conditions at a young age

    Lucas Siqueira Trindade, Seong-Joon Park, Toshimitsu Komatsu, Haruyoshi Yamaza, Hiroko Hayashi, Ryoichi Mori, Takuya Chiba, Isao Shimokawa, Kazunao Kuramoto

    Acta Medica Nagasakiensia   55 ( 2 ) 85 - 92  2011  [Refereed]

     View Summary

    AMP-activated protein kinase (AMPK) is a key molecule that controls energy homeostasis at cellular and whole body levels. Calorie restriction (CR) may exhibit the anti-aging effect through modulation of AMPK activity. We investigated the hepatic AMPK pathways for gluconeogenesis (the transducer of regulated cyclic adenosine monophosphate response element-binding protein (CREB) 2
    CRTC2) and cell growth (mammalian target of rapamycin, mTOR). Male F344 rats at 2.5 months (mo) and 18 mo of age were subjected to 4-mo-long 30% CR
    control rats were fed ad libitum (AL) throughout the experiment. Rats were killed 15 min after saline or glucose injection to evaluate activation of signal molecules under transient hyperglycemic and subsequent hyperinsulinemic conditions. Western blot analyses demonstrated a modest reduction of threonine-172-phosphorylated (p)-AMPKα levels and an increment of nuclear CRTC2 in the young CR group as compared with the age-matched AL group. We also confirmed the increased binding of CRTC2 and CREB and up-regulation of gluconeogenic genes (PGC-1α and PEPCK) in the CR group. However, there was no CR-specific alteration in total or phosphorylated mTOR levels. The results suggest down-regulation of hepatic AMPK activity by CR for metabolic adaptation that promotes gluconeogenesis. The effect of CR on mTOR remains elusive. © 2011, Nagasaki University School of Medicine. All rights reserved.

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • Development of a bioassay to screen for chemicals mimicking the anti-aging effects of calorie restriction

    Takuya Chiba, Tomoshi Tsuchiya, Toshimitsu Komatsu, Ryoichi Mori, Hiroko Hayashi, Hitoshi Shimano, Stephen R. Spindler, Isao Shimokawa

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   401 ( 2 ) 213 - 218  2010.10

     View Summary

    Suppression of the growth hormone/insulin-like growth factor-I pathway in Ames dwarf (DF) mice, and caloric restriction (CR) in normal mice extends lifespan and delays the onset of age-related disorders. In combination, these interventions have an additive effect on lifespan in Ames DF mice. Therefore, common signaling pathways regulated by DF and CR could have additive effects on longevity. In this study, we tried to identity the signaling mechanism and develop a system to assess pro-longevity status in cells and mice. We previously identified genes up-regulated in the liver of DF and CR mice by DNA microarray analysis. Motif analysis of the upstream sequences of those genes revealed four major consensus sequence motifs, which have been named dwarfism and calorie restriction-responsive elements (DFCR-REs). One of the synthesized sequences bound to hepatocyte nuclear factor-4 alpha (HNF-4 alpha), an important transcription factor involved in liver metabolism. Furthermore, using this sequence information, we developed a highly sensitive bioassay to identify chemicals mimicking the anti-aging effects of CR. When the reporter construct, containing an element upstream of a secreted alkaline phosphatase (SEAP) gene, was co-transfected with HNF-4 alpha and its regulator peroxisome proliferator-activated receptor (PPAR) gamma coactivator-1 alpha (PGC-1 alpha). SEAP activity was increased compared with untransfected controls. Moreover, transient transgenic mice established using this construct showed increased SEAP activity in CR mice compared with ad libitum-fed mice. These data suggest that because of its rapidity, ease of use, and specificity, our bioassay will be more useful than the systems currently employed to screen for CR mimetics, which mimic the beneficial effects of CR. Our system will be particularly useful for high-throughput screening of natural and synthetic candidate molecules. (C) 2010 Elsevier Inc. All rights reserved.

    DOI

    Scopus

    11
    Citation
    (Scopus)
  • SIRT1 Regulates Thyroid-Stimulating Hormone Release by Enhancing PIP5Kγ Activity through Deacetylation of Specific Lysine Residues in Mammals

    Asai-Akieda S, Zaima N, Ikegami K, Kahyo T, Yao I, Hatanaka T, Iemura S, Sugiyama R, Yokozeki T, Eishi Y, Koike M, Ikeda K, Chiba T, Yamaza H, Shimokawa I, Song S, Matsuno A, Mizutani A, Sawabe M, Chao MV, Tanaka M, Kanaho Y, Natsume T, Sugimura H, Date Y, McBurney MW, Guarente L, Setou M

    PLoS ONE   5 ( 7 ) e11755 - e11755  2010.07

     View Summary

    Background: SIRT1, a NAD-dependent deacetylase, has diverse roles in a variety of organs such as regulation of endocrine function and metabolism. However, it remains to be addressed how it regulates hormone release there.
    Methodology/Principal Findings: Here, we report that SIRT1 is abundantly expressed in pituitary thyrotropes and regulates thyroid hormone secretion. Manipulation of SIRT1 level revealed that SIRT1 positively regulated the exocytosis of TSH-containing granules. Using LC/MS-based interactomics, phosphatidylinositol-4-phosphate 5-kinase (PIP5K) c was identified as a SIRT1 binding partner and deacetylation substrate. SIRT1 deacetylated two specific lysine residues (K265/K268) in PIP5K gamma and enhanced PIP5K gamma enzyme activity. SIRT1-mediated TSH secretion was abolished by PIP5K gamma knockdown. SIRT1 knockdown decreased the levels of deacetylated PIP5K gamma, PI(4,5) P-2, and reduced the secretion of TSH from pituitary cells. These results were also observed in SIRT1-knockout mice.
    Conclusions/Significance: Our findings indicated that the control of TSH release by the SIRT1-PIP5K gamma pathway is important for regulating the metabolism of the whole body.

    DOI

    Scopus

    36
    Citation
    (Scopus)
  • FoxO1 is involved in the antineoplastic effect of calorie restriction

    Haruyoshi Yamaza, Toshimitsu Komatsu, Saori Wakita, Carole Kijogi, Seongjoon Park, Hiroko Hayashi, Takuya Chiba, Ryoichi Mori, Tatsuo Furuyama, Nozomu Mori, Isao Shimokawa

    Aging Cell   9 ( 3 ) 372 - 382  2010.06  [Refereed]

     View Summary

    The FoxO transcription factors may be involved in the antiaging effect of calorie restriction (CR) in mammals. To test the hypothesis, we used FoxO1 knockout heterozygotic (HT) mice, in which the FoxO1 mRNA level was reduced by 50%, or less, of that in wild-type (WT) mouse tissues. The WT and HT mice were fed ad libitum (AL) or 30% CR diets from 12 weeks of age. Aging- and CR-related changes in body weight, food intake, blood glucose, and insulin concentrations were similar between the WT and HT mice in the lifespan study. The response to oxidative stress, induced by intraperitoneal injection of 3-nitropropionic acid (3-NPA), was evaluated in the liver and hippocampus at 6 months of age. Several of the selected FoxO1-target genes for cell cycle arrest, DNA repair, apoptosis, and stress resistance were up-regulated in the WT-CR tissues after 3-NPA injection, while the effect was mostly diminished in the HT-CR tissues. Of these gene products, we focused on the nuclear p21 protein level in the liver and confirmed its up-regulation only in the WT-CR mice in response to oxidative stress. The lifespan did not differ significantly between the WT and HT mice in AL or CR conditions. However, the antineoplastic effect of CR, as indicated by reduced incidence of tumors at death in the WT-CR mice, was mostly abrogated in the HT-CR mice. The present results suggest a role for FoxO1 in the antineoplastic effect of CR through the induction of genes responsible for protection against oxidative and genotoxic stress. © 2010 The Authors Journal compilation © Blackwell Publishing Ltd/Anatomical Society of Great Britain and Ireland 2010.

    DOI PubMed CiNii

    Scopus

    70
    Citation
    (Scopus)
  • Similar metabolic responses to calorie restriction in lean and obese Zucker rats

    Takuya Chiba, Toshimitsu Komatsu, Masahiko Nakayama, Toshiyuki Adachi, Yukari Tamashiro, Hiroko Hayashi, Haruyoshi Yamaza, Yoshikazu Higami, Isao Shimokawa

    MOLECULAR AND CELLULAR ENDOCRINOLOGY   309 ( 1-2 ) 17 - 25  2009.10

     View Summary

    Calorie restriction (CR), which is thought to be largely dependent on the neuroendocrine system modulated by insulin/insulin-like growth factor-I (IGF-1) and leptin signaling, decreases morbidity and increases lifespan in many organisms. To elucidate whether insulin and leptin sensitivities are indispensable in the metabolic adaptation to CR, we investigated the effects of CR on obese Zucker (fa/fa) rats and lean control (+/+) rats. CR did not fully improve insulin resistance in (fa/fa) rats. Nonetheless, CR induced neuropeptide Y (NPY) expression in the hypothalamic arcuate nucleus and metabolism related gene expression changes in the liver in (fa/fa) rats and (+/+) rats. Up-regulation of NPY augmented plasma corticosterone levels and suppressed pituitary growth hormone (GH) expression, thereby modulating adipocytokine production to induce tissue-specific insulin sensitivity. Thus, central NPY activation via peripheral signaling might play a crucial role in the effects of CR, even in insulin resistant and leptin receptor deficient conditions. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

    DOI

    Scopus

    25
    Citation
    (Scopus)
  • Identification and characterization of an insulin receptor substrate 4-interacting protein in rat brain: Implications for longevity

    Takuya Chiba, Daisuke Inoue, Aya Mizuno, Toshimitsu Komatsu, Satoshi Fujita, Haruaki Kubota, Maria Luisa Tagliaro, Seongjoon Park, Lucas Siqueira Trindade, Takahiro Hayashida, Hiroko Hayashi, Haruyoshi Yamaza, Yoshikazu Higami, Isao Shimokawa

    NEUROBIOLOGY OF AGING   30 ( 3 ) 474 - 482  2009.03

     View Summary

    The hypothalamus is organized as a collection of distinct, autonomously active nuclei that regulate discrete functions, such as feeding activity and metabolism. We used suppression subtractive hybridization (SSH) to identify genes that are enriched in the hypothalamus of the rat brain. We screened a subtractive library of 160 clones, and 4 genes that were predominantly expressed in the hypothalamus, compared to other brain regions. The mRNA for a member of the WD-repeat family of proteins, WDR6, was abundantly expressed in the hypothalamus, and we found that WDR6 interacted with insulin receptor substrate 4 (IRS-4) in the rat brain. Interestingly, WDR6 gene expression in the hypothalamic arcuate nucleus was decreased by caloric restriction, and in growth hormone (GH)-antisense transgenic rats, both of which are associated with an increased life span. Insulin-like growth factor (IGF)-I and insulin treatment increased WDR6 gene expression in mouse hypothalamus-derived GT 1-7 cells. Our results might suggest that WDR6 participates in insulin/IGF-I signaling and the regulation of feeding behavior and longevity in the brain. (C) 2007 Elsevier Inc. All rights reserved.

    DOI

    Scopus

    16
    Citation
    (Scopus)
  • A ROLE FOR FOXO1 IN THE EFFECT OF CALORIE RESTRICTION

    Isao Shimokawa, Haruyoshi Yamaza, Takuya Chiba, Tatsuo Furuyama

    JOURNAL OF PHYSIOLOGICAL SCIENCES   59   111 - 111  2009  [Refereed]

  • A transgenic dwarf rat strain as a tool for the study of immunosenescence in aging rats and the effect of calorie restriction

    Isao Shimokawa, Masanori Utsuyama, Toshimitsu Komatsu, Haruyoshi Yamaza, Takuya Chiba

    Handbook on Immunosenescence: Basic Understanding and Clinical Applications     131 - 144  2009

     View Summary

    Immunosenescence or dysregulation of the immune system may accelerate the aging process and shorten the lifespan in animals. Calorie restriction, a well-known nutritional intervention for longevity in laboratory animals, retards immunosenescence and modulates the immunosystem. These effects of CR could contribute partly to extending the lifespan. A transgenic (Tg) dwarf rat strain, in which the growth hormone (GH) axis is selectively suppressed, lived longer and exhibited several phenotypes similar to those in CR rats, suggesting an important role for the GH axis in the effect of CR. Here, we describe the longevity, pathology, thymic and splenic lymphocyte subpopulations and response to endotoxin in Tg rats in comparison with CR rats. The findings support the importance of the GH axis in the effect of CR on the immune system and, in particular, longevity. The Tg rats could be a useful tool to better understand the molecular mechanisms underlying the antiaging effect of CR.

    DOI

  • Longevity Genes: Insights from Calorie Restriction and Genetic Longevity Models

    Isao Shimokawa, Takuya Chiba, Haruyoshi Yamaza, Toshimitsu Komatsu

    MOLECULES AND CELLS   26 ( 5 ) 427 - 435  2008.11

     View Summary

    In this review, we discuss the genes and the related signal pathways that regulate aging and longevity by reviewing recent findings of genetic longevity models in rodents in reference to findings with lower organisms. We also paid special attention to the genes and signals mediating the effects of calorie restriction (CR), a powerful intervention that slows the aging process and extends the lifespan in a range of organisms. An evolutionary view emphasizes the roles of nutrient-sensing and neuroendocrine adaptation to food shortage as the mechanisms underlying the effects of CR. Genetic and non-genetic interventions without CR suggest a role for single or combined hormonal signals that partly mediate the effect of CR. Longevity genes fall into two categories, genes relevant to nutrient-sensing systems and those associated with mitochondrial function or redox regulation. In mammals, disrupted or reduced growth hormone (GH)-insulin-like growth factor (IGF)-1 signaling robustly favors longevity. CR also suppresses the GH-IGF-1 axis, indicating the importance of this signal pathway. Surprisingly, there are very few longevity models to evaluate the enhanced anti-oxidative mechanism, while there is substantial evidence supporting the oxidative stress and damage theory of aging. Either increased or reduced mitochondrial function may extend the lifespan. The role of redox regulation and mitochondrial function in CR remains to be elucidated.

  • Pituitary growth hormone suppression reduces resistin expression and enhances insulin effectiveness: Relationship with caloric restriction

    Takuya Chiba, Haruyoshi Yamaza, Toshimitsu Komatsu, Masahiko Nakayama, Satoshi Fujita, Hiroko Hayashi, Yoshikazu Higami, Isao Shimokawa

    EXPERIMENTAL GERONTOLOGY   43 ( 6 ) 595 - 600  2008.06

     View Summary

    Caloric restriction (CR) retards various age-dependent disorders, increases lifespan, and improves insulin activity in laboratory animals. Recently, adipocytes were found to act together as an active endocrine organ that produces various hormones called adipocytokines. The peripheral and central activities of these adipocytokines have been suggested to mediate the anti-aging effects of CR. Here, we tested this notion by analyzing the effect of CR and suppression of growth hormone/insulin-like growth factor-1 (GH/IGF-I) axis on the expression of resistin, adiponectin, and adipsin genes by rat white adipose tissue (WAT). We found that CR and GH/IGF-I suppression markedly downregulated resistin gene expression. We also found plasma resistin levels correlated positively with pituitary GH mRNA expression levels. Our observations suggest that CR reduces resistin expression and increases insulin effectiveness in a GH/IGF-I-dependent manner. The beneficial effects of CR and GH/IGF-I suppression appear to be mediated, at least in part, by changes in glucose metabolism that result from reductions in plasma resistin levels. (c) 2008 Elsevier Inc. All rights reserved.

    DOI

    Scopus

    22
    Citation
    (Scopus)
  • The ATR-mediated S phase checkpoint prevents rereplication in mammalian cells when licensing control is disrupted

    Enbo Liu, Alan Yueh-Luen Lee, Takuya Chiba, Erin Olson, Peiqing Sun, Xiaohua Wu

    JOURNAL OF CELL BIOLOGY   179 ( 4 ) 643 - 657  2007.11

     View Summary

    DNA replication in eukaryotic cells is tightly controlled by a licensing mechanism, ensuring that each origin. res once and only once per cell cycle. We demonstrate that the ataxia telangiectasia and Rad3 related (ATR)-mediated S phase checkpoint acts as a surveillance mechanism to prevent rereplication. Thus, disruption of licensing control will not induce significant rereplication in mammalian cells when the ATR checkpoint is intact. We also demonstrate that single-stranded DNA (ssDNA) is the initial signal that activates the checkpoint when licensing control is compromised in mammalian cells. We demonstrate that uncontrolled DNA unwinding by minichromosome maintenance proteins upon Cdt1 overexpression is an important mechanism that leads to ssDNA accumulation and checkpoint activation. Furthermore, we show that replication protein A 2 and retinoblastoma protein are both downstream targets for ATR that are important for the inhibition of DNA rereplication. We reveal the molecular mechanisms by which the ATR-mediated S phase checkpoint pathway prevents DNA rereplication and thus significantly improve our understanding of how rereplication is prevented in mammalian cells.

    DOI

    Scopus

    58
    Citation
    (Scopus)
  • Role of insulin and growth hormone/insulin-like growth factor-I signaling in lifespan extension: Rodent longevity models for studying aging and calorie restriction

    T. Chiba, H. Yamaza, I. Shimokawa

    CURRENT GENOMICS   8 ( 7 ) 423 - 428  2007.11

     View Summary

    Insulin/insulin-like growth factor-I (IGF-I) pathways are recognized as critical signaling pathways involved in the control of lifespans in lower organisms to mammals. Caloric restriction (CR) reduces plasma concentration of insulin, growth hormone (GH), and IGF-I. CR retards various age-dependent disorders such as nuerodegenerative diseases and extends lifespan in laboratory rodents. These beneficial effects of CR are partly mimicked in spontaneous or genetically engineered rodent models of reduced insulin and GH/IGF-I axis. Most of these long-living rodents show increased insulin sensitivity; however, recent study has revealed that some other rodents show normal or reduced insulin sensitivity. Thus, increased insulin sensitivity might be not prerequisite for lifespan extension in insulin/GH/IGF-I altered longevity rodent models. These results highlighted that, for lifespan extension, the intracellular signaling molecules of insulin/GH/IGF-I pathways might be more important than actual peripheral or systemic insulin action.

  • FoxO1 is not involved in the calorie restriction-specific response to oxidative stress in mice liver

    Toshimitsu Komatsu, Yuri Fukumoto, Hirosato Mashima, Tatsuo Furuyama, Takuya Chiba, Haruyoshi Yamaza, Yoshikazu Higami, Isao Shimokawa

    AGE   29 ( 2-3 ) 122 - 122  2007.09  [Refereed]

  • Identification of fasting-induced genes in the rat hypothalamus - Relationship with neuroprotection

    Takuya Chiba, Satoshi Fujita, Haruaki Kubota, Daisuke Inoue, Aya Mizuno, Toshimitsu Komatsu, Haruyoshi Yamaza, Yoshikazu Higami, Isao Shimokawa

    MOLECULAR MECHANISMS AND MODELS OF AGING   1119   216 - 226  2007

     View Summary

    During food shortage, organisms activate defense mechanisms to maximize their chance of survival. At least in part, these responses are triggered by changes in hormonal status and neural status during starvation. The hypothalamus is organized as a collection of distinct autonomously active nuclei and is considered to play crucial roles in these survival responses. To isolate factors involved in these pathways, we carried out suppression subtractive hybridization analyses using complementary DNAs (cDNA) from the hypothalami of fasted and fed rats. We identified four genes, namely ubiquitin-conjugating enzyme E2D 3 (UBE2D3), cAMP-dependent protein kinase C beta subunit (PKC beta), excitatory amino acid carrier 1 (EAAC1), and ferritin heavy polypeptide 1 (Fth1), that were upregulated after a 48-h fast compared to the fed status. According to previous reports, these genes have been implicated in protection against neuronal cell death under various neurodegenerative stresses, such as hvpoxia-ischemia and oxidative stress. Thus, the increased expressions 4 the genes identified in the present study may have protective effects against neural damage that could otherwise result in cell death.

    DOI

    Scopus

    9
    Citation
    (Scopus)
  • カロリー制限による寿命延長の分子機構

    千葉卓哉, 下川 功

    医学の歩み   217 ( 7 ) 769 - 773  2006.05

    Authorship:Lead author

  • Effect of leptin on hypothalamic gene expression in calorie-restricted rats

    Toshimitsu Komatsu, Takuya Chiba, Haruyoshi Yamaza, Kazuo To, Hiroaki Toyama, Yoshikazu Higami, Isao Shimokawa

    Journals of Gerontology - Series A Biological Sciences and Medical Sciences   61 ( 9 ) 890 - 898  2006  [Refereed]

     View Summary

    Diminished leptin signaling to the arcuate nucleus of hypothalamus (ARH) may induce calorie restriction (CR)-specific neuroendocrine and metabolic adaptation, which is potentially relevant to the effect of CR. The present study investigated whether restoration of leptin signaling to the ARH could reverse CR-induced alterations in neuropeptide gene expression in rats. Male F344 rats, fed ad libitum or a 30% CR diet from 6 weeks of age, received leptin or vehicle intracerebroventricularly for 14 days via osmotic mini-pumps implanted in the subcutis at 34 weeks of age. The messenger RNA levels were quantified by real-time reverse transcription-polymerase chain reaction using total RNA extracted from microdissected tissues containing the ARH. The results indicated that leptin administration reversed the upregulated expression of neuropeptide Y and agouti-related protein genes in CR rats, suggesting the possibility of a role for the leptin-ARH pathway in the effect of CR. Copyright 2006 by The Gerontological Society of America.

    DOI PubMed

    Scopus

    14
    Citation
    (Scopus)
  • Glucose metabolism in calorie-restricted or transgenic dwarf rat : Analysis of adiponectin-AMPK pathway

    HAYASHI H., YAMAZA H., TOU K., TOUYAMA H., KOMATSU T., CHIBA T., HIGAMI Y., SHIMOKAWA I.

      29 ( 3 ) 31 - 34  2005  [Refereed]

    CiNii

  • Expression of DNase gamma during Fas-independent apoptotic DNA fragmentation in rodent hepatocytes

    Y Higami, T Tsuchiya, K To, T Chiba, H Yamaza, D Shiokawa, S Tanuma, Shimokawa, I

    CELL AND TISSUE RESEARCH   316 ( 3 ) 403 - 407  2004.06

     View Summary

    Endonuclease-induced DNA fragmentation is a hallmark of apoptosis. DNase gamma (DNase gamma) was recently identified as one of the endonucleases responsible for apoptotic DNA fragmentation. In this study, immunohistochemistry for DNase gamma was performed on paraffin sections of rodent liver in well-defined models of hepatocyte apoptosis induced by Fas antibody (Fas) or cycloheximide (CHX), and necrosis induced by lipopolysaccharide (LPS) or carbon tetrachloride (CCl4). DNase gamma immunoreactivity was compared with TdT-mediated dUTP nick-end labeling (TUNEL) reactivity. Our results showed TUNEL reactivity in both apoptotic and necrotic hepatocytes. DNase gamma immunoreactivity was not detected during LPS-induced or CCl4-induced hepatocyte necrosis. In contrast, it was evident during CHX-induced, but not Fas-induced, apoptotic DNA fragmentation. These findings suggest that DNase gamma plays an important role in Fas-independent apoptotic DNA fragmentation in hepatocytes.

    DOI

    Scopus

    7
    Citation
    (Scopus)
  • Mouse testis transcriptome revealed using serial analysis of gene expression

    JJ Yao, T Chiba, J Sakai, K Hirose, M Yamamoto, A Hada, K Kuramoto, K Higuchi, M Mori

    MAMMALIAN GENOME   15 ( 6 ) 433 - 451  2004.06

     View Summary

    We applied serial analysis of gene expression (SAGE) to the mouse testis to reveal the global gene expression profile and to identify senescence-dependent changes in that profile. A total of 61,929 SAGE tags, including 19,323 unique tags, were obtained from 3- and 29-month-old BDF1 mice and 14-month-old SAMP1 mice. Genes highly expressed in the testis included those associated with spermatogenesis, protein metabolism, energy metabolism, growth and differentiation, and signal transduction. Testes from old mice of both strains appeared atrophied. Morphological examination of aged testes revealed extremely thin seminiferous epithelia and significantly decreased numbers of spermatids and spermatocytes. Despite the physical deterioration, no gross changes in the gene expression profile were apparent in the testes of old BDF1 mice. However, in 14-month-old SAMP1 mice, protamine 2 gene transcription was approximately 50% lower than in BDF1 mice. This reduction may be associated with the oligozoospermia and early decline in reproductive performance of SAMP1 mice. Our SAGE results are the first quantitative gene expression profile of the mouse testis and provide a reliable transcriptome reference for this organ.

    DOI

  • SV40 T antigen interacts with Nbs1 to disrupt DNA replication control

    XH Wu, D Avni, T Chiba, F Yan, QP Zhao, YF Lin, H Heng, D Livingston

    GENES & DEVELOPMENT   18 ( 11 ) 1305 - 1316  2004.06

     View Summary

    Nijmegen breakage syndrome (NBS) is characterized by radiation hypersensitivity, chromosomal instability, and predisposition to cancer. Nbs1, the NBS protein, forms a tight complex with Mrell and Rad50, and these interactions contribute to proper double-strand break repair. The simian virus 40 (SV40) oncoprotein, large T antigen (T), also interacts with Nbs1, and T-containing cells experience chromosomal hyperreplication in a manner dependent on T/Nbs1 complex formation. A substantial fraction of NBS-deficient fibroblasts reinitiate DNA replication in discrete regions, and wild-type Nbs1 corrects this defect. Similarly, synthesis of an N-terminal Nbs1 fragment induced DNA rereplication and tetraploidy, in NBS-deficient but not NBS-proficient cells. Moreover, SV40 origin-containing DNA hyperreplicated in T-containing NBS-deficient cells by comparison with T-containing, Nbs1-reconstituted derivatives. Thus, Nbs1 suppresses rereplication of cellular DNA and SV40 origin-containing replicons, and T targets Nbs1, thereby enhancing the yield of new SV40 genomes during viral DNA replication.

    DOI

    Scopus

    74
    Citation
    (Scopus)
  • Life span extension by reduction of the growth hormone-insulin-like growth factor-1 axis: relation to caloric restriction.

    Shimokawa I, Higami Y, Tsuchiya T, Otani H, Komatsu T, Chiba T, Yamaza H

    FASEB J   17 ( 9 ) 1108 - 1109  2003.06

  • Effects of caloric restriction on gene expression in the arcuate nucleus

    Shimokawa, I, T Fukuyama, K Yanagihara-Outa, M Tomita, T Komatsu, Y Higami, T Tuchiya, T Chiba, Y Yamaza

    NEUROBIOLOGY OF AGING   24 ( 1 ) 117 - 123  2003.01

     View Summary

    Neuroendocrine alterations that repress energy-costly physiologic processes such as reproduction and growth and induce stress responses, might underlie the antiaging effect of caloric restriction (CR). Neurons in the arcuate nucleus of the hypothalamus (ARH) might have a pivotal role in these neuroendocrine alterations. We investigated the effects of CR on gene expression of neuropeptide Y (NPY), proopiomelanocortin (POMC), growth hormone-releasing hormone (GHRH), somatostatin (SRIH), and cyclophilin (CP) in the ARH in male F344 rats at 6 months of age. Rats were fed ad libitum or a 30% caloric restricted diet with a modified alternate-days feeding regimen from 6 weeks of age. Reverse transcription-polymerase chain reaction (RT-PCR) methods were used to quantify mRNA levels over multiple time points during the 12-h/12-h dark/light cycle over a 2-days feeding cycle. The present study demonstrated that CR increased NPY-mRNA levels, but decreased POMC, GHRH, and CP mRNA levels differentially over the feeding cycle. The SRIH level was not significantly affected by CR. The present results support the neuroendocrine hypothesis of CR. (C) 2002 Elsevier Science Inc. All rights reserved.

  • Anti-aging effects of caloric restriction: Involvement of neuroendocrine adaptation by peripheral signaling

    T Chiba, H Yamaza, Y Higami, Shimokawa, I

    MICROSCOPY RESEARCH AND TECHNIQUE   59 ( 4 ) 317 - 324  2002.11

     View Summary

    Many hormonal signals from peripheral tissues contribute to the regulation of energy homeostasis and food intake. These regulators including leptin, insulin, and ghrelin, modulate the orexigenic and anorexigenic neuropeptide expression in hypothalamic nuclei. The anti-aging effects of caloric restriction have been explained from an evolutional viewpoint of the adaptive response of the neuroendocrine and metabolic response systems to maximize survival during periods of food shortage. In organisms, excess energy is stored in adipose tissues as a triglyceride preparation for such survival situations. Adipose tissue has recently been recognized as an endocrine organ, and leptin, as secreted by adipocyte, seems to be an especially important factor for the adaptive response to fasting and neuroendocrine alterations under caloric restriction. In this review, we discuss the potential involvement of neuroendocrine modulators in longevity and the anti-aging effects of caloric restriction. (C) 2002 Wiley-Liss, Inc.

    DOI

    Scopus

    48
    Citation
    (Scopus)
  • Life span extension by reduction in growth hormone-insulin-like growth factor-1 axis in a transgenic rat model

    Shimokawa, I, Y Higami, M Utsuyama, T Tuchiya, T Komatsu, T Chiba, H Yamaza

    AMERICAN JOURNAL OF PATHOLOGY   160 ( 6 ) 2259 - 2265  2002.06

     View Summary

    The longer life span in dwarf mice suggests that a reduction in the growth hormone (GH)-insulin-like growth factor (IGF)-1 axis retards aging and extends the life span in mammals. We tested this hypothesis in a transgenic strain of rats whose GH gene was suppressed by an anti-sense GH transgene. Male rats homozygous for the transgene (tg/tg) had a reduced number of pituitary GH cells, a lower plasma concentration of IGF-1, and a dwarf phenotype. Heterozygous rats (tg/-) had an intermediate phenotype in plasma IGF-1, food intake, and body weight between tg/tg and control (-/-) rats. The life span of tg/tg rats was 5 to 10% shorter than -/- rats. In contrast, the life span of tg/- rats was 7 to 10% longer than -/- rats. Pathological analysis suggested that neoplasms caused earlier death in tg/tg rats; in contrast, tg/- rats had reduced nonneoplastic diseases and a prolonged life span. Immunological analysis revealed a smaller population and lower activity of splenic natural killer cells in tg/tg rats. The results of the present study support the hypothesis, but suggest that there is an optimal level of the GH-IGF-1 axis to maximize survival in mammals.

  • Extrahepatic expression of apolipoprotein A-II in mouse tissues: Possible contribution to mouse senile amyloidosis

    L Fu, Matsuyama, I, T Chiba, YM Xing, T Korenaga, ZJ Guo, XY Fu, J Nakayama, M Mori, K Higuchi

    JOURNAL OF HISTOCHEMISTRY & CYTOCHEMISTRY   49 ( 6 ) 739 - 747  2001.06

     View Summary

    Apolipoprotein A-II (apoA-II), an apolipoprotein in serum high-density lipoprotein, is a precursor of mouse senile amyloid fibrils. The liver has been considered to be the primary site of synthesis. However, we performed nonradioactive in situ hybridization analysis in tissue sections from young and old amyloidogenic (R1.P1-Apoa2(C)) and amyloid-resistant (SAMR1) mice and revealed that other tissues in addition to the liver synthesize apoA-II. We found a strong hybridization signal in the basal cells of the squamous epithelium and the chief cells of the fundic gland in the stomach, the crypt cells and a small portion of the absorptive epithelial cells in the small intestine, the basal cells of the tongue mucosa, and the basal cells of the epidermis and hair follicles in the skin in both mouse strains. Expression of apoA-II mRNA in those tissues was also examined by RT-PCR analysis. Immunolocalization of apoA-II protein also indicated the cellular localization of apoA-II. ApoA-II transcription was not observed in the heart. Amyloid deposition was observed around the cells expressing apoA-II mRNA in the old R1.P1-Apoa2(C) mice. These results demonstrate that the apoA-II mRNA is transcribed and translated in various extrahepatic tissues and suggest a possible contribution of apoA-II synthesized in these tissues to amyloid deposition.

  • Transmission of mouse senile amyloidosis

    YM Xing, A Nakamura, T Chiba, K Kogishi, T Matsushita, F Li, ZJ Guo, M Hosokawa, M Mori, K Higuchi

    LABORATORY INVESTIGATION   81 ( 4 ) 493 - 499  2001.04

     View Summary

    In mouse senile amyloidosis, apolipoprotein A-II polymerizes into amyloid fibrils (AApoAII) and deposits systemically. Peripheral injection of AApoAII fibrils into young mice induces systemic amyloidosis (Higuchi et at, 1998). We isolated AApoAII amyloid fibrils from the livers of old R1.P1-Apoa2(c) mice and injected them with feeding needles into the stomachs of young R1.P1-Apoa2(c) mice for 5 consecutive days. After 2 months, all mice had AApoAII deposits in the lamina propria of the small intestine. Amyloid deposition extended to the tongue, stomach, heart, and liver at 3 and 4 months after feeding. AApoAII suspended in drinking water also induced amyloidosis. Amyloid deposition was induced in young mice reared in the same cage for 3 months with old mice who had severe amyloidosis. Detection of AApoAII in feces of old mice and induction of amyloidosis by the injection of an amyloid fraction of feces suggested the propagation of amyloidosis by eating feces. Here, we substantiate the transmissibility of AApoAII amyloidosis and present a possible pathogenesis of amyloidosis, ie, oral transmission of amyloid fibril conformation, where we assert that exogenous amyloid fibrils act as templates and change the conformation of endogenous amyloid protein to polymerize into amyloid fibrils.

  • Unique mutations in mitochondrial DNA of senescence-accelerated mouse (SAM) strains

    J. Mizutani, T. Chiba, M. Tanaka, K. Higuchi, Masayuki Mori

    Journal of Heredity   92 ( 4 ) 352 - 355  2001  [Refereed]

     View Summary

    Mitochondrial DNA (mtDNA) is exclusively inherited maternally and hence could offer a good method for tracing the lineage of mouse strains. We examined the mtDNA sequence of senescence-accelerated mouse (SAM) strains as well as other laboratory strains of inbred mice to deduce the ancestral strain of SAM. Four unique mutations were identified at bases 2256, 10,847, 11,181, and 13,053 in SAM strains. The mutations were not found in other mouse strains including AKR/J, one of the parental strains of SAM. Comparison of the mtDNA sequences also led to the consensus mtDNA sequence of laboratory strains of inbred mice. The seven laboratory strains of common inbred mice showed polymorphisms at base 9348, thymine repeat from base 9818, and adenine repeat from base 9821, and could be classified into five types by combination of the differences. Although we could not identify mouse strains with the same type of mtDNA as SAM in this study, the polymorphisms would provide a promising clue to ascertain the ancestral strain(s) of SAM. The polymorphism in mtDNA could be used to ascertain the genealogy of other mouse strains as well.

    PubMed

  • Mouse senile amyloid deposition is suppressed by adenovirus-mediated overexpression of amyloid-resistant apolipoprotein A-II

    T Chiba, K Kogishi, J Wang, C Xia, T Matsushita, J Miyazaki, Saito, I, M Hosokawa, K Higuchi

    AMERICAN JOURNAL OF PATHOLOGY   155 ( 4 ) 1319 - 1326  1999.10

     View Summary

    Apolipoprotein A-II (apoA-II), the second most abundant apolipoprotein of serum high density lipoprotein, deposits as an amyloid fibril (AApoAII) in old mice. Mouse strains with a high incidence of senile amyloidosis have the type C apoA-II gene (Apoa2(c)), whereas the strains with a low incidence of amyloidosis have the type B apoA-II gene (Apoa2(b)). in this study, to investigate whether the type B apoA-II protein inhibits the extension of amyloid fibrils, we constructed an adenovirus vector bearing the Apoa2(b) cDNA (Adex1CATApoa2(b)), which is expressed under the control of a hepatocyte-specific promoter. The mice were infected with Adex1CATApoa2(b) before induction of amyloidosis by the injection of AApoAII amyloid fibril seeds. Compared with the mice infected with the control virus, amyloid deposition was suppressed significantly in the mice infected with Adex1CATApoa2(b). Fluorometry using thioflavine T also revealed that AApoAII fibril extension was inhibited by the addition of type B apoA-II in vitro. Thus, we propose that Apoa2(b) contributes as an active inhibitor of amyloid fibril extension and overexpression of amyloid-resistant gene variant may be an attractive therapeutic target in amyloidosis.

  • Fibrilization in mouse senile amyloidosis is fibril conformation-dependent

    K Higuchi, K Kogishi, J Wang, Chen, X, T Chiba, T Matsushita, Y Hoshii, H Kawano, T Ishihara, T Yokota, M Hosokawa

    LABORATORY INVESTIGATION   78 ( 12 ) 1535 - 1542  1998.12

     View Summary

    Amyloidosis refers to a group of diseases characterized by tissue deposition of amyloid fibrils. A single intravenous injection of a very small amount of the native mouse senile amyloid fibrils (AApoAII) induced severe systemic amyloid deposition in young mice having the amyloidogenic apoA-II gene (Apoa2(c)). After AApoAII injection, amyloid deposition occurred rapidly and advanced in an accelerated manner, as observed in spontaneous senile amyloidosis in mice. However, the injection of denatured AApoAII, native apoA-II in high-density lipoprotein (HDL), and denatured apoA-II monomer, which have the same primary structure but without a fibril conformation, did not induce amyloidosis. No amyloid deposition was observed in mice having an amyloid-resistant apoA-II gene (Apoa2(b)) even 3 months after AApoAII injection. Significantly less amyloid deposition was observed in mice having both types of apoA-II genes heterozygously (Apoa2(b/c)). These findings suggest that the nucleation-dependent polymerization found in vitro also occurs in vivo, and that the fibril conformation is required for the injected amyloid fibrils to act as seeds in vivo. Fibril conformation-dependent fibrillization is proposed as a general model of the pathogenesis of various kinds of amyloidosis occurring in vivo; it may be useful in both elucidating the pathogenesis of amyloidosis and developing effective therapeutic modalities to treat this disease.

  • Accumulation of pro-apolipoprotein A-II in mouse senile amyloid fibrils.

    Higuchi K, Kogishi K, Wang J, Xia C, Chiba T, Matsushita T, Hosokawa M

    Biochem J.   325 ( 3 ) 653 - 659  1997.04

▼display all

Books and Other Publications

  • 生物の寿命延長〜老化・長寿命の基盤研究最前線〜 第6章 第1節 食事制限による寿命延長作用の分子メカニズム:遺伝子改変による長寿命マウスとの類似性から見た栄養センシング経路の重要性

    谷津智史, 近藤嘉高, 千葉卓哉

    エヌ・ティー・エス  2022.03

  • 別冊「医学のあゆみ」老化メカニズムの徹底究明 分子からアンチエイジングまで 15.カロリー制限による抗老化機構の解明とその制御物質の探索

    近藤嘉高、伊藤麻衣子、千葉卓哉

    医歯薬出版  2021.02

  • はじめての老化学・病理学-人間科学のためのライフサイエンス入門-

    千葉卓哉( Part: Sole author)

    コロナ社  2016.04

  • 老化抑制および老化関連疾患治療薬としてのカロリー制限模倣物—その標的分子とシグナル伝達系—

    千葉卓哉, 大畑佳久

    医学のあゆみ  2015

  • Food and longevity genes, Bioactive Food as Dietary Interventions for the Aging Population. Edited by Ronald Ross Watson and Victor R. Preedy

    Shimokawa I, Chiba T

    Elsevier Inc  2013

  • カロリー制限摸倣物 老化・寿命のサイエンス (実験医学)

    千葉卓哉, 下川功( Part: Contributor)

    羊土社  2013

  • サーチュインと老化、寿命「レスベラトロールの基礎と応用」

    下川 功, 千葉 卓哉, 森 亮一( Part: Contributor)

    シーエムシー出版  2012

  • Bioactive foods and chronic disease states: Food and longevity genes.

    Shimokawa I, Chiba T( Part: Contributor)

    2012

  • Handbook on Immunosenescence, A transgenic dwarf rat strain as a tool for the study of immunosenescence in aging rats and the effect of calorie restriction.

    Shimokawa I, Utsuyama M, Komatsu T, Yamaza H, Chiba T( Part: Contributor)

    Springer Science Business Media  2009

  • 内分泌モデル(GH/IGF-I)動物 老化・老年病研究のための動物実験ガイドブック

    千葉卓哉, 山座治義, 下川 功

    アドスリー  2008

▼display all

Misc

  • マウス臓器におけるグルコン酸キナーゼの遺伝子発現に関する研究

    袁一ぶん, 王梓, 吉井幸, 石神昭人, 千葉卓哉, 近藤嘉高

    日本分子生物学会年会プログラム・要旨集(Web)   43rd  2020

    J-GLOBAL

  • DEVELOPMENT OF A REPROTER ASSAY SYSTEM TO SCREEN FOR CHEMICALS MIMICKING THE ANTI-AGING EFFECTS OF CALORIE RESTRICTION

    T. Chiba, T. Tsuchiya, I. Shimokawa

    ANNALS OF NUTRITION AND METABOLISM   63   1559 - 1560  2013

    Research paper, summary (international conference)  

  • FoxO1 is involved in the antineoplastic effect of calorie restriction

    Isao Shimokawa, Toshimitsu Komatsu, Ryoichi Mori, Hiroko Hayashi, Takuya Chiba

    FASEB JOURNAL   25  2011.04

    Research paper, summary (international conference)  

  • Development of a bioassay system to screen for chemicals mimicking the anti-aging effects of calorie restriction

    T. Chiba, T. Tsuchiya, S. Nishizono, I. Shimokawa

    ANNALS OF NUTRITION AND METABOLISM   58   218 - 218  2011

    Research paper, summary (international conference)  

  • Molecular mechanisms of aging and the point of anti-aging strategy

    Ryoichi Mori, Toshimitsu Komatsu, Takuya Chiba, Isao Shimokawa

    Diabetes Frontier   21 ( 1 ) 26 - 31  2010

  • Mechanisms of anti-aging effects of calorie restriction: Metabolic adaptation hypothesis and applications for human longevity

    Takuya Chiba, Isao Shimokawa

    Anti-Aging Medicine   5 ( 4 ) 53 - 61  2009

▼display all

Industrial Property Rights

  • 寿命延長関連遺伝子およびその用途

    千葉卓哉, 下川 功, 樋上賀一, 山座治義

    Patent

  • カロリー制限模倣物のスクリーニング方法

    特許5652755

    千葉卓哉, 土谷智史, 下川 功

    Patent

Awards

  • 第18回オレオサイエンス賞

    2019.09   日本油化学会  

    Winner: 千葉 卓哉

  • Registration Scholarship

    2012.10   Keystone Symposia (Aging and Diseases of Aging)  

    Winner: 千葉 卓哉

  • 10th Euro Fed Lipid Congress, Best poster.

    2012.09  

  • 第28回角尾学術賞

    2011.05  

  • 学術奨励賞

    2011.04   平成22年度日本病理学会  

  • 平成21年度長崎県科学技術奨励賞

    2010.03  

  • 奨励賞

    2009.06   第32回日本基礎老化学会大会  

  • 優秀演題

    2007.10   第25回日本老年学会総会  

    Winner: 千葉 卓哉

  • 長崎医学同窓会賞

    2006.06   抗老化薬開発基盤の構築

▼display all

Research Projects

  • 新規エネルギー代謝関連分子WDR6の機能解析

    Project Year :

    2015.04
    -
    2018.03
     

     View Summary

    インスリン/インスリン様成長因子-Iおよびレプチンシグナルは、加齢性疾患の発症に深く関与していることが示唆されている。それらの疾患に至るシグナル伝達系の解明は、健康長寿社会を実現する上で重要な研究課題である。我々は、これらのシグナルに関わる新規の代謝調節分子WD repeat protein 6 (WDR6)を単離した。WDR6はタンパク質間の相互作用に重要なWDモチーフを複数持つタンパク質であり、インスリンおよびレプチンシグナルとの関連が示唆されている。本研究では、WDR6が糖・脂質代謝の制御、DNA損傷応答の活性化による発ガン抑制、酸化ストレス耐性制御などに関与していることを明らかにするために遺伝子改変動物を作製して研究を行った。本年度はCre-loxPシステムによって作製した全身性ノックアウト(KO)マウスと、タモキシフェン誘導性脳特異的WDR6 KOマウスの開発を実施した。作製した全身性KOマウスをもちいて、インスリン負荷試験と糖負荷試験を行い、インスリンシグナル

  • Development and application of a reporter bioassay system to screen for phytochemicals mimicking the anti-aging effects of caloric restriction

    Project Year :

    2013.04
    -
    2016.03
     

     View Summary

    Caloric restriction (CR) without malnutrition in normal mice, and suppression of the GH/IGF-I axis in spontaneous mutant Ames dwarf (DF) mice, extend lifespan and delay the onset of various age-dependent disorders. Combined, these two lifespan-prolonging interventions have an additive effect in DF mice. We aimed to identity the intracellular signaling pathways mediating these effects, and to develop a system to screen anti-aging phytochemicals both in vitro and in vivo. We identified HNF-4 alpha and Nrf2, important transcription factors involved in glucose and lipid metabolism and oxidative stress resistance, respectively, might critical regulators for longevity gene regulations. We also found that taurine could mimic the anti-aging effects such as increased oxidative stress resistance. These results indicate that our bioassay system would be useful to screen for chemicals, which mimic the beneficial effects of CR without actual food restriction

  • Development of a bioassay system to screen anti-aging chemicals and characterization of candidate molecules

    Project Year :

    2012.04
    -
    2014.03
     

     View Summary

    In this study, we tried to identify the intracellular signaling pathways and develop a system to screen anti-aging chemicals both in vitro and in vivo. We found that one of the synthesized sequences of identified motifs bound to hepatocyte nuclear factor-4 (HNF-4). When the reporter construct, containing an element upstream of a secreted alkaline phosphatase (SEAP) gene, was co-transfected with HNF-4 and its regulator peroxisome proliferator-activated receptor-gamma coactivator 1 (PGC-1), activity of SEAP was increased dose-dependently in comparison to untransfected controls. Moreover, transgenic mice established using this construct showed increased SEAP activity both calorie restriction (CR) and candidate chemical-fed mice in comparison to ad libitum fed mice. Interestingly, oxidative stress resistance was correlated with SEAP activity of these transgenic mice. These data suggest that our bioassay would be useful to screen for CR mimetic photochemical both in vitro and in vivo

  • Regulation of the aging by calorie restriction: Implications of mitochondrial retrograde signals

    Project Year :

    2010.04
    -
    2014.03
     

     View Summary

    Calorie restriction (CR) may exert anti-aging effects by modulating mitochondrial functions. We previously reported that CR upregulated mitochondrial proteins, including Cox6b1, a subunit of cytochrome c oxidase (Cox). To investigate the functional roles of Cox6b1 in mitochondria, we conducted in vitro experiments using Cox6b1-overexpressing cells or knockdown cells. The findings suggest that Cox6b1 mediates some of the effects, e.g., stress resistance, of CR by enhancing mitochondrial respiration via the assembly of Cox supercomplexes. The simultaneous generation of ROS may be prevented by several mechanisms, including Nrf2 activation. We also found that inhibition of glycogen synthase kinase (GSK)-3b, a putative upstream signaling molecule for Cox6b1, increased Cox6b1 protein expression. Accordingly, we confirmed that CR increased phosphorylated GSK-3b, its inactive form, in the mouse liver. The present study supports the mitohormesis hypothesis of CR

  • Regulation of aging in mammals : Difference between the effects of calorie restriction and suppression of the GH-IGF-1 axis

     View Summary

    1.Insulin signaling : The insulin signaling was analyzed in liver and skeletal muscle in CR and GH-IGF-1-suppressed transgenic (Tg) rats. The results suggested that CR not only sensitized the insulin action for glucose metabolism but also activated insulin-independent pathways. These mechanisms induced by CR could result from the suppressed GH-IGF-1 axis (Yamaza H et al., Exp Gerontol 2004 ; Hayashi H et al. Biomedical Gerontol 2005). We investigated a potential role for the adiponectin-AMP-activated protein kinase (AMPK) pathway in insulin-independent mechanisms. However, unexpectedly, CR suppressed the activity of AMPK and also the suppressed GH-IGF-1 axis did not affect the AMPK pathway.2.Stress response : We analyzed the inflammatory stress response in CR rats using the DNA array method. The results confirmed the stress-resistance in CR rats. The DNA array analysis in liver suggested that the protective effect by CR emerges from constitutively, rather than NF-kappa B-inductively, expressed gene products (Tsuchiya T et al., Mech Ageing Develop 2005). GH-IGF-1-suppressed rats exhibited greatly enhanced stress response. This effect could be partly due to attenuation of the NF-kapp

  • Dbf4/Cdc7によるS期チェックポイント制御機構の解明

     View Summary

    1.DNA傷害時におけるDbf4/Cdc7のリン酸化の解析(1)DNA傷害によるDbf4のリン酸化とATM/ATRとの関連ATM/ATR過剰発現細胞をもちいてIR(20Gy),UV(50J/m2),HU(1mM,24hrs),etoposide(50μM,24hrs)処理後のDbf4のリン酸化をSDS-PAGEにより解析した。その結果これらのDNA傷害誘導処理とATM/ATRの過剰発現を組み合わせることによりDbf4のリン酸化が増強される可能性を示唆する結果が得られた。(2)ATM/ATRによるDbf4のリン酸化部位の解析Dbf4には7つのATM/ATRによるリン酸化のコンセンサス配列(S/TQ)が存在する。GST融合タンパクを作製し、site-directed mutagenesisによりアラニン変異体を作製しATM/ATRによるリン酸化部位を同定した。その結果、5つのSQ/TQ部位がATM/ATRによるリン酸化の標的である可能性が示唆された。その他の2カ所については継続して解析している。2.Dbf4のリン酸化変異体および抗リン酸化抗体の作製同定した5つのリン酸化部位をアラニン(A ; phospho-negative)またはグルタミン酸(D ; phospho-mimic)に変異させ、表現型解析にもちいるDbf4

  • Suppressed cellular damage and inflammation, and altered metabolism by caloric restriction via SREBP1/LXR

  • Mechanisms underlying the effect of calorie restriction : Analyses of neuropeptide Y and receptor subtypes

  • Identification and characterization of WDR6, a novel insulin signaling molecule

     View Summary

    We have isolated WD-repeat protein 6 (WDR6), a novel hypothalamus enriched gene in rat brain tissue. Amino acid sequence revealed that WDR6 have protein phosphatase motif and WD-repeat motif that have important roles for dephosphorylation and protein-protein interaction, respectively. Our study revealed that WDR6 physically interacted with insulin receptor substare-4 (IRS-4), which is abundantly expressed in the hypothalamus. These results suggest that WDR6 could regulate insulin/IGF-I signal in brain. Further study on WDR6 functions might contribute to the development of drugs for the treatment of neurodegenerative diseases, such as cognitive disorders

▼display all

Presentations

  • インスリンシグナルに関与する新規代謝関連分子WDR6と相互作用するタンパク質の同定

    吉井幸, 王梓, エンイチブン, 中川香里, 谷津智史, 近藤嘉高, 千葉卓哉

    第44回日本分子生物学会年会 

    Event date:
    2021.12
     
     
  • ペントースリン酸経路におけるグルコン酸キナーゼの臓器分布に関する研究

    エンイチブン, 吉井幸, 中川香里, 石神昭人, 千葉卓哉, 近藤嘉高

    第44回日本分子生物学会 

    Event date:
    2021.12
     
     
  • 新規インスリンシグナル分子WDR6と相互作用するタンパク質の網羅的同定

    吉井幸, 王梓, エンイチブン, 近藤嘉高, 千葉卓哉

    第21回抗加齢医学会総会 

    Event date:
    2021.06
     
     
  • The distinct tissue distribution of enzymes in pentose phosphate pathway of mouse

    Event date:
    2021.06
     
     
  • Tissue distribution of enzymes involved in pentose phosphate pathway of mice

    Presentation date: 2021.02

  • マウスにおけるグルコン酸キナーゼの遺伝子発現に関する研究

    エンイチブン, 王梓, 吉井幸, 石神昭人, 千葉卓哉, 近藤嘉高

    第43回日本分子生物学学会年会 

    Presentation date: 2020.12

  • タウリンによるカロリー制限模倣効果の検討:脂質代謝、抗酸化、オートファジーに与える影響の解析

    王梓、エンイチブン, 吉井幸, 近藤嘉高, 西園祥子, 千葉卓哉

    令和2年度日本栄養・食糧学会九州・沖縄支部大会 

    Presentation date: 2020.11

  • Tissue distribution of enzymes involved in pentose phosphate pathway of mice

    Presentation date: 2020.11

  • WDR6は栄養応答とLC3発現制御に関与している

    吉井幸, 大畑佳久, 王梓, 渡辺由香里, エンイチブン, 小松利光, 原太一, 近藤嘉高, 下川功, 千葉卓哉

    第43回日本基礎老化学会大会 

    Event date:
    2020.05
     
     
  • マウスにおけるグルコン酸キナーゼの臓器発現

    エンイチブン, 王梓, 吉井幸, 千葉卓哉, 近藤嘉高

    第43回日本基礎老化学会大会 

    Event date:
    2020.05
     
     
  • ペントースリン酸副経路で働くヒトおよびマウスにおけるグルコン酸キナーゼの同定

    近藤嘉高, 千葉卓哉, 石神昭人

    第43回日本基礎老化学会大会 

    Event date:
    2020.05
     
     
  • マウスにおけるグルコン酸キナーゼの臓器発現に関する研究

    エンイチブン, 王梓, 吉井幸, 千葉卓哉, 近藤嘉高

    早稲田大学応用脳科学研究所 応用脳科学カンファレンス2020 

    Presentation date: 2020.02

  • Longevity genes.

    Shimokawa I, Chiba T, Yamaza H, Komatsu T

    The 10th International Symposium on Vascular Aging : molecular exploration and micro-inflammatory implications. 

    Presentation date: 2018.12

  • 老化制御シグナルを標的とした抗老化薬開発の現状~不老長寿は実現可能か?~

    千葉 卓哉  [Invited]

    第412回川崎医学会講演会 

    Presentation date: 2018.05

  • タウリン摂取が脂質代謝および酸化ストレス耐性に与える効果

    千葉 卓哉  [Invited]

    第12回遺伝子栄養学研究会学術集会 

    Presentation date: 2017.08

  • 老化のメカニズム:健康長寿の実現のために

    千葉 卓哉  [Invited]

    第13回 ひと・健康・未来シンポジウム2016 浜松、加齢を知る、老いを健やかに 

    Presentation date: 2016.12

  • Calorie restriction mimetic effects of taurine supplementation mediated through lipid metabolism and oxidative stress resistance

    千葉 卓哉

    ISNFF 

    Presentation date: 2016.10

  • カロリー制限による抗老化作用:その分子機構と模倣物探索

    千葉 卓哉

    第70回 日本栄養・食糧学会中部支部大会公開シンポジウム 『食品機能学研究の最先端 -食品成分による疾病予防-』 

    Presentation date: 2016.06

  • 老化制御を目指した食品開発の展望

    千葉 卓哉  [Invited]

    地(知)の拠点大学による地域創生推進事業(COC+)企画シンポジウム「 健康志向食品開発の展望」 

    Presentation date: 2016.03

  • Development and application of a reporter bioassay system to screen for phytochemicals mimicking the anti-aging effects of caloric restriction

    千葉 卓哉

    Pacifichem 2015(環太平洋国際科学会議) 

    Presentation date: 2015.12

  • ラットを用いた老化制御因子の探索

    千葉 卓哉  [Invited]

    日本基礎老化学会大会シンポジウム 

    Presentation date: 2015.10

  • カロリー制限による抗老化作用の分子機構

    千葉 卓哉  [Invited]

    日本食品免疫学会シンポジウム 

    Presentation date: 2015.10

  • Development of a reporter assay system to screen for phytochemicals mimicking the anti-aging effects of calorie restriction

    千葉 卓哉

    12th Asian Congress of Nutrition 

    Presentation date: 2015.05

  • An essential role for neuropeptide Y in anti-aging effects of calorie restriction

    千葉 卓哉

    7th International Conference and Exhibition on Nutraceuticals and Functional Foods, 

    Presentation date: 2014.10

  • カロリー制限による寿命延長・抗老化作用の標的分子とその制御因子

    千葉 卓哉  [Invited]

    第11回認知症サプリメント研究会 

    Presentation date: 2014.10

  • 食事制限の抗老化作用における中枢ー末梢の臓器連関

    千葉 卓哉  [Invited]

    東京都健康長寿医療センター研究所 

    Presentation date: 2014.08

  • カロリー制限による抗老化作用の標的シグナルとその制御物質

    千葉 卓哉  [Invited]

    慶應義塾大学医学部 

    Presentation date: 2014.06

  • Necessity of Neuropeptide Y for the Effect of Dietary Restriction in Mice

    The 65th Annual Meeting of Gerontological Society of America 

    Presentation date: 2012.11

  • Disruption of neuropeptide Y gene limits stress resistance and lifespan extension effects of calorie restriction in mice

    10th Euro Fed Lipid Congress 

    Presentation date: 2012.09

  • カロリー制限に対する代謝の応答はインスリンおよびレプチン抵抗性を示す肥満ラットにおいても起こる

    千葉 卓哉

    BMB2008(第31回日本分子生物学会年会・第81回日本生化学会大会 合同大会) 

    Presentation date: 2008.12

  • Calorie restriction increases TORC2-dependent CREB activity for induction of gluconeogenetic gene expression by down-regulation of AMPK.

    Trindade LS, Park S, Komatsu T, Yamaza H, Chiba T, Higami Y, Shimokawa I.

    The 9th International Congress on Cell Biology 

    Presentation date: 2008.10

  • Calorie restriction-specific adipose tissue metabolic profile: different from the effect of growth hormone suppression.

    Park S, Komatsu T, Hayashi H, Trindade LS, Yamaza H, Chiba T, Shimokawa I

    The 9th International Congress on Cell Biology 

    Presentation date: 2008.10

  • 老化促進モデルマウスSAMP8の学習記憶能における食餌成分およびカロリー制限の影響

    千葉 卓哉

    第51回日本神経化学会 

    Presentation date: 2008.09

  • Identification and characterization of food deprivation-activated genes and insulin receptor substrate interacting protein

    千葉 卓哉

    The Japan-Korea Joint Seminar (AACL2008)-Toward the establishment of Asian Aging Research and Education Center 

    Presentation date: 2008.09

  • Does a high fat diet inhibit mobilization of bone marrow (BM) progenitor stem cells

    Trindade LS, Nagai K, Park S, Chiba T, Yamaza H, Shimokawa I

    The Japan-Korea Joint Seminar (AACL2008)-Toward the establishment of Asian Aging Research and Education Center 

    Presentation date: 2008.09

  • Calorie restriction-specific adipose tissue metabolic profile: difference from the effect of growth hormone suppression.

    Park S, Komatsu T, Hayashi H, Trindade LS, Yamaza H, Chiba T, Shimokawa I

    The Japan-Korea Joint Seminar (AACL2008)-Toward the establishment of Asian Aging Research and Education Center 

    Presentation date: 2008.09

  • Calorie restriction disrupts hepatic insulin signal transduction in mice.

    Yamaza H, Park S, Chiba T, Shimokawa I

    The Japan-Korea Joint Seminar (AACL2008)-Toward the establishment of Asian Aging Research and Education Center 

    Presentation date: 2008.09

  • GH/IGF-I系の抑制は白色脂肪組織におけるresistin発現を減少させ血糖値を低下させる

    千葉 卓哉

    第31回日本基礎老化学会 

    Presentation date: 2008.06

  • WD-repeat protein 6は視床下部におけるエネルギーセンシングと関連している

    千葉 卓哉

    第50回日本日本神経化学会 

    Presentation date: 2007.09

  • Insulin/IGF-Iシグナル関連新規遺伝子WD repeat protein 6の同定と解析

    千葉 卓哉

    第30回日本基礎老化学会 

    Presentation date: 2007.06

  • カロリー制限による寿命延長作用の解明(insulin/IGF-Iシグナルを中心として)

    千葉 卓哉

    第1回エイジング・バイオストレス・メタボリズム研究会 

    Presentation date: 2007.04

  • Zuckerラットをもちいたカロリー制限によるアディポサイトカイン発現変化の解析

    千葉 卓哉

    第28回日本分子生物学会 

    Presentation date: 2005.12

▼display all

Specific Research

  • 新規インスリンシグナル関連分子WDR6による病態制御機構の解明

    2021  

     View Summary

     実験動物に対して与える餌の量を制限することを意味するカロリー制限、およびインスリンシグナル系に関与する分子の機能減弱によって、多くの生物の寿命延長や老化に伴って罹患率が上昇する疾患の発症が抑制されることが知られている。我々はこれまでに、脳の視床下部で高発現しているWD repeat protein 6 (WDR6)が、インスリンシグナル系に関与する分子として摂食行動やエネルギー代謝などに関連している可能性を明らかにした。本研究では、全身性および組織特異的WDR6ノックアウトマウスの作製と表現型解析を目指して研究を行った。 これまでに、Cre-loxPシステムをもちいたWDR6ノックインマウスを作製しており、当該キメラマウスをCreリコンビナーゼを全身性に発現するCAG-Creマウスと交配させ、ヘテロノックアウトマウスを作製した。その後、C57BL/6マウスに戻し交配を繰り返し、C57BL/6を遺伝的背景とする全身性WDR6ノックアウトマウスを作製した。ホモ同士の交配によっても仔マウスが得られたことから、WDR6ノックアウトマウスは胎生致死でなく、また生殖細胞系にも異常が見られないことが示唆された。 現在、全身性WDR6ノックアウトマウスをもちいて、インスリン受容体基質-4 (IRS-4)、およびliver kinase B1 (LKB1)などの代謝関連タンパク質のシグナル伝達系について解析を行っている。さらに、糖・脂質代謝の変化、および酸化ストレスなどに対する耐性等について解析を行っている。

  • タウリンの健康増進作用に関する研究

    2021  

     View Summary

     タウリン(2-アミノエタンスルホン酸)はイカやタコ等の魚介類に含まれている含硫アミノ酸様化合物の1つであり、小腸で吸収され、胆汁酸の抱合基として重要である。本研究では、タウリンによる脂質濃度低下の作用メカニズムを解明するために、タウリンを添加した食餌をラットに摂食させ、成長パラメーター、血清脂質および血清グルコース濃度、肝臓脂質濃度ならびに肝臓における脂質代謝関連遺伝子のmRNA発現量の測定、および酸化ストレス耐性に与える影響を解析した。また、培養細胞をもちいてタウリン添加による酸化ストレス耐性の詳細についても解析を行った。 その結果、血清および肝臓のコレステロール濃度はタウリンの添加量に依存して低下し、肝臓における中性脂肪濃度はタウリンの添加量に依存して低い値を示した。タウリンの脂質代謝関連遺伝子の発現量を測定した結果、タウリンは脂肪酸合成に関わる遺伝子のmRNAの発現量を低下させ、脂肪酸の燃焼に関与する遺伝子のmRNA発現量を増加させた。また、胆汁酸合成の律速酵素の一つとして知られる遺伝子のmRNA発現量を低下させた。さらに、これらの遺伝子発現は、遺伝子発現調節に関与する遺伝子のmRNA発現量レベルで制御されていることが示唆された。以上の結果から、タウリンは肝臓での脂質代謝を遺伝子レベルで調節することが示唆された。 また、タウリン添加による酸化ストレス耐性の亢進が、ラットおよび培養細胞をもちいた解析で示唆された。この酸化ストレス耐性の亢進には、タウリンによる抗酸化酵素の発現誘導が関与していることが示唆された。

  • ゲノム編集技術を応用した老化とがん化の共通原理の解明

    2020  

     View Summary

    CRISPR-Cas9システムによるゲノム編集技術およびRNA干渉法をもちいて、インスリンシグナル関連分子の機能を改変した細胞株を樹立した。マウス線維芽細胞由来3T3-L1細胞は、脂肪細胞様細胞への分化誘導法が確立された細胞株である。この細胞に対して我々が単離した新規遺伝子の機能を破壊し、そのことが脂肪細胞への分化とオートファジーに対してどのような影響を与えるかについて解析した。その結果、一定の条件下において、この遺伝子が欠損することにより脂肪細胞への分化とオートファジー制御が変化することが示唆された。

  • ゲノム編集技術を応用した老化とがん化の共通原理の解明

    2020  

     View Summary

    本研究では、DNA損傷応答と発がん抑制に関して、インスリンシグナルの下流に存在する分子の関与を明らかにすることで、老化と発がんのmissing linkの解明を目指して実験を行った。CRISPR-Cas9システムによるゲノム編集技術をもちいて、インスリンシグナル関連分子の機能を改変した細胞株を樹立した。ヒト胎児腎臓由来293細胞、マウス線維芽細胞由来3T3-L1細胞、マウス肝細胞由来細胞をもちいて改変を行った。また、これらの細胞に、オーファジーを検出可能な、GFP-RFP-LC3レポーター遺伝子を導入した細胞株を樹立した。

  • ゲノム編集技術を応用した老化とがん化の共通原理の解析

    2019  

     View Summary

    我々はinsulin/IGF-Iシグナル関連分子と示唆されるWD repeat-containing protein6 (WDR6) を遺伝子サブトラクション法により同定し、脳においては摂食調節に重要な視床下部において高発現していることを見出した。本研究では、WDR6の機能欠損による表現型解析をin vivoおよびin vitroにおいて行った。全身性WDR6 KOマウスおよび野生型マウスを、自由摂食(AL)および30%カロリー制限(CR)で飼育した4群のマウスを用いて体重や摂食量の変化など基礎的パラメーターを解析した。また、HeLa細胞を用いてWDR6をノックアウトし、オートファジー関連タンパク質の発現解析を行った。その結果、WDR6の発現低下は栄養センシングに関わる因子の活性を抑制し、オートファジーの活性化、さらには脂肪組織においてCRの効果を模倣する可能性が示唆された。

  • 機能性食品成分の細胞保護作用に関する研究

    2018  

     View Summary

    本研究では培養細胞を用いてタウリンの抗酸化効果に関して検証した。COS1細胞に対してタウリン含有培養液で培養した後にUV照射に由来する酸化ストレスに対する応答について解析した。その結果、UV照射による活性酸素の発生量の低下がタウリン添加によって確認された。さらにミトコンドリアの膜電位の状態の解析を行った結果、UV照射を行っても、タウリン処理によってミトコンドリアへのダメージが軽減されることが示唆された。これらの結果から、タウリンは細胞に対する酸化ストレス傷害を減弱させる作用をもつ可能性が示唆された。

  • 機能性食品成分の抗酸化および抗老化効果に関する研究

    2017  

     View Summary

     摂取カロリーを70%に抑えるカロリー制限(CR)は、実験動物の老化を遅らせ、寿命を延長させる最も確実な介入方法である。しかし、ヒトに対するCRを長期間実施することは難しく、CRと同様の効果を有するCR模倣物の研究が注目されている。本研究ではタウリンがCR模倣物として機能すると考え解析を行った。 酸化ストレスを負荷したマウスにタウリン混餌食を与えた結果、抗酸化に関わる遺伝子の発現が上昇した。タンパク質発現の解析を行ったところ、酸化ストレスマーカーの発現がタウリン食によって低下していた。さらにDNA損傷マーカーやアポトーシスマーカーの発現にも影響を与えていた。これの結果から、タウリンの摂取が抗酸化、さらには抗老化に有利に働く可能性が強く示唆された。

  • 健康寿命の延伸に寄与する食品成分の探索とその作用機序の解明

    2017  

     View Summary

    カロリー制限(CR)は抗老化・抗酸化作用を誘導し健康寿命を延伸することが様々な生物で報告されている。そのためCRと同様の効果を持つCR模倣物の研究が広く行われている。本研究ではタウリンがCR模倣物として機能し、寿命の延伸にも関わるのではないかと考え解析を行った。培養細胞を用いた解析から、UV照射によるDNA損傷応答が、タウリンの添加によって減弱することが示唆された。この結果は、タウリン処理によって酸化ストレスの誘導が軽減されたことを示唆している。したがって、タウリンが新たなCR模倣物の候補となる可能性があり、今後の更なる検討が必要であると思われる。

  • 農産品由来成分の抗加齢機能性評価およびその作用機序解析

    2016  

     View Summary

     カロリー制限(CR)は、実験動物の老化を遅らせ、寿命を延長させる最も確実な介入方法である。その抗老化作用には、摂食促進の作用を持つニューロペプチドY (NPY)の発現亢進が重要であり、NPYの活性化がCRを行った際の体内シグナル伝達を模倣、または増幅可能なことが示唆されている。そこで本研究では、NPY発現亢進作用が知られている六君子湯に着目し、マウスに六君子湯を混ぜた餌を投与し、酸化ストレスに対する耐性および生体応答を解析した。 その結果、六君子湯がNPYの発現亢進を介し、肝臓ではCRの(1)抗酸化能を上昇させる効果、(2)酸化ストレスに応答し細胞周期を停止させる効果、(3)アポトーシスを誘導する効果、(4)ミトコンドリア機能を改善する効果を模倣または増幅可能なことが示唆された。

  • 機能性食品成分の抗老化効果に関する総合的研究

    2016  

     View Summary

     カロリー制限(CR)は、実験動物の老化を遅らせ、寿命を延長させる最も確実な介入方法である。その抗老化作用に関連するシグナル伝達系はまだ不明な点が多いが、酸化ストレスの抑制が重要であることが示唆されている。そこで本研究では、培養細胞に紫外線(UV)を照射して酸化ストレスを誘導し、食品由来成分であるタウリン(Tau)がその酸化ストレスの蓄積を軽減するかを解析した。 その結果、UV処理細胞と比べ、Tau + UV処理細胞では酸化ストレスが抑制されていることが示唆された。タンパク質レベルでは、チェックポイントタンパクであるp-Chk1がUV未処理の細胞に比べ、UV処理細胞において発現が亢進した。タウリン処理はこのChk1のリン酸化を低下させたことからも、タウリンによる酸化ストレス抑制作用が示唆された。これらの結果から、タウリンがCRの抗老化作用を一部模倣することが可能であると示唆された。

  • 長寿遺伝子サーチュインのゲノム保護作用による発ガン予防:機能性食品によるその制御

    2016  

     View Summary

     カロリー制限(calorie restriction: CR)は、実験動物の老化を遅らせ、寿命を延長させる最も確実な介入方法である。その抗老化作用に関連するシグナル伝達系はまだ不明な点が多いが、サーチュインと呼ばれる長寿遺伝子の関与が示唆されている。そこで本研究では、サーチュインを活性化させる植物由来成分であるレスベラトロールをマウスの餌に混ぜ、ドキソルビシンによって誘導される酸化ストレスによるDNA損傷に対する保護作用を解析した。 その結果、CRによる脂質代謝関連遺伝子の発現上昇は、ドキソルビシン投与によって抑制され、レスベラトロールを投与されたマウスにおいても同様にそれらの遺伝子の発現上昇は見られなかった。しかし、レスベラトロールを投与したマウスはサーチュイン遺伝子の発現が上昇し、このことが通常食を投与したマウスと比較して酸化ストレス耐性が亢進したことと関連があると示唆された。

  • 老化関連疾患の予防効果が期待される機能性食品成分の評価系構築とその応用

    2015  

     View Summary

     本研究では、タウリンのカロリー制限模倣効果について解析を行った。実験1では4週齢のラットに2週間タウリン含有食を与え、体重、血液生化学などのバイオマーカを解析した。実験2ではマウスにタウリン添加食を与え、3-ニトロプロピオン酸投与による酸化ストレス耐性を解析した。実験1において、血清および肝臓コレステロール濃度はタウリンの添加量に依存して低下した。また、肝臓中性脂肪濃度がタウリンの添加量依存的に低下した。実験2では、タウリン添加によって酸化ストレス誘導後の生存率を上昇させることが示された。これらの結果から、タウリンはカロリー制限模倣物となる可能性を持つと考えられた。

  • 新規インスリンシグナル分子を標的とした老化疾患研究モデルマウス開発と分子病態解析

    2013  

     View Summary

    実験動物に対して与える餌の量を制限すること(カロリー制限)、およびインスリンシグナル系の減弱により、寿命の延長や老化関連疾患の発症が抑制されることが知られている。我々はこれまでに、脳の視床下部で高発現している新規遺伝子、WD repeat protein 6 (WDR6)が、インスリンシグナル系の分子として摂食行動やエネルギー代謝などに関連している可能性を明らかにした。本研究では、全身性および脳特異的WDR6ノックアウトマウスの作製を行った。また、得られたマウスの摂食行動など、表現型解析に関する基礎的な研究を行った。 これまでに、Cre-loxPシステムをもちいたWDR6ノックインマウスを作製しており、当該キメラマウスをCreを全身性に発現するCAG-Creマウスと交配させ、ヘテロノックアウトマウスを作製した。その後、ヘテロ同士の交配によりホモノックアウトマウスを作製した。得られたマウスの遺伝子型の分離比は概ね野生型:ヘテロ:ホモ、1:2:1であり、メンデル遺伝の法則に従っていた。また、ホモ同士の交配によっても仔マウスが得られたことから、WDR6ノックアウトマウスは胎生致死でなく、また生殖細胞系にも異常が見られないことが示唆された。脳特異的WDR6ノックアウトマウスは、タモキシフェンによって神経細胞においてのみCreの発現が誘導されるNestin-CreERTマウスとの交配により行った。現在、ハウスの繁殖と交配を継続して行っている。 全身性WDR6ノックアウトマウスの野生型、ヘテロ、ホモの遺伝子判定は、尾部から抽出したゲノムDNAをもちいて行った。得られたマウスの肝臓より、RNAを抽出し、WDR6の遺伝子発現をRT-PCR法により解析した。その結果、RNAレベルにおいても目的とした標的遺伝子組換えが起こっていることが示唆された。今後は、インスリン受容体基質-4(IRS-4)、およびliver kinase B1(LKB1)などの代謝関連タンパク質とWDR6の相互作用を、免疫沈降法をもちいて解析し、WDR6ノックアウトによるタンパク質-タンパク質間の結合への影響を解析する。現在までのところ、若齢においては遺伝子型による摂食行動に対する明確な違いは認められていない。今後も、これらのマウスの飼育を老齢まで継続するとともに、糖・脂質代謝の変化、さらに酸化ストレスなどに対する耐性等を解析する予定である。これらの研究を通じて、WDR6ノックアウトマウスを新たな老化疾患研究モデル動物として確立することを目指す。

  • インスリンシグナルによる老化制御機構の解明:時空間的イメージング解析を利用して

    2012  

     View Summary

    インスリンシグナル系による老化制御機構に重要な役割をもつ転写因子複合体の機能解明、およびその活性化分子を明らかにするため、以下の研究を行った。1.In vitroスクリーニング系の確立抗老化に関与する転写因子が結合し、転写を活性化させると示唆されるDNA配列である、DFCR-RE(モチーフ2)を直列に5個結合させ、分泌型アルカリフォスファターゼ(SEAP)の上流に組み込み、さらに選択用のpuromycin耐性遺伝子を導入したコンストラクトを作製した。マウス肝臓由来培養細胞であるTLR2細胞(SV40形質転換細胞)にこのプラスミドをトランスフェクトし、構成的発現細胞株を3系統樹立した。あわせてネガティブコントロール用として、別のDFCR-RE配列(モチーフ5)についても、同様に3系統の細胞株を樹立した。SEAPの発現量をもとに、それぞれ1系統の細胞株を選択し、以下の実験を行った。2.確立した細胞株をもちいたスクリーニング東京大学創薬オープンイノベーションセンターより化合物ライブラリーの提供を受け(36種類)、上記の細胞系をもちいたスクリーニングを行った。36化合物をそれぞれ1μMの濃度で細胞の培地に添加し、0, 24, 48, 72時間後に培養上清を採取し、アッセイキットをもちいてSEAP活性を測定した。この結果をもとに化合物を選択し、さらに以下の解析を行った。3.スクリーニング系の最適化上記の実験で決定したポジティブコントロールとして期待される化合物をもちいて、培養液中に濃度、処理時間を変化させて添加し、培地中に分泌されたSEAPの活性を測定した。その結果、化合物番号5番について期待されるSEAP活性の変化は見られたものの、統計的な有意差は見られなかった。4.HNF-4/PGC-1の結合促進および転写活性化の解析上記の化合物番号5番をもちいた実験について、PGC-1の発現およびHNF-4/PGC-1複合体の形成変化について、それぞれウエスタンブロット、免疫沈降法をもちいて解析した。その結果、PGC-1の発現は化合物の添加に対して濃度依存的な上昇が見られたものの、複合体形成の明らかな増加は見られなかった。以上の結果から、化合物添加前のレポーター発現がより低いコンストラクトが必要であることが示唆された。現在、あらたなレポータープラスミドの作製を行っている。

▼display all

Overseas Activities

  • 老化関連疾患の発症メカニズムおよび治療法に関する基礎研究

    2018.03
    -
    2019.03

    米国   スクリプス研究所

 

Syllabus

▼display all

 

Committee Memberships

  • 2011.04
    -
    Now

    日本抗加齢医学会  評議員

  • 2011.04
    -
    Now

    日本病理学会  学術評議員

  • 2008.06
    -
    Now

    老化促進モデルマウス(SAM)学会  評議員

  • 2006.06
    -
    Now

    日本基礎老化学会  評議員

  • 2013.12
    -
    2015.11

    日本学術振興会  科学研究費委員会専門委員