Yoshihiro Tsuchiya

Publications (10)54.94 Total impact

• Article: Role of Pin1 in the pathogenesis of non-alcoholic steatohepatitis in a rodent model.

  Yusuke Nakatsu, Yuichiro Otani, Hideyuki Sakoda, Jun Zhang, Ying Guo, Hirofumi Okubo, Akifumi Kushiyama, Midori Fujishiro, Takako Kikuchi, Toshiaki Fukushima, [......], Yoshihiro Tsuchiya, Hideaki Kamata, Akiko Nagamachi, Toshiya Inaba, Fusanori Nishimura, Hideki Katagiri, Shin-Ichiro Takahashi, Hiroki Kurihara, Takafumi Uchida, Tomoichiro Asano
  [show abstract] [hide abstract]
  ABSTRACT: Non-alcoholic steatohepatitis (NASH) is a disorder characterized by simultaneous fat accumulation and chronic inflammation in the liver. In this study, Pin1 expression was revealed to be markedly increased in the livers of mice with MCDD (Methionine choline-deficient diet)-induced NASH, a rodent model of NASH. In addition, Pin1 KO mice were highly resistant to MCDD-induced NASH, based on a series of data showing simultaneous fat accumulation, chronic inflammation and fibrosis in the liver. In terms of Pin1-induced fat accumulation, it was revealed that the expression levels of PPARα and its target genes were higher in the livers of Pin1 KO mice than in controls. Thus, resistance of Pin1 KO mice to hepatic steatosis is partially attributable to lack of Pin1-induced down-regulation of PPARα, although multiple other mechanisms are apparently involved. Another mechanism involves the enhancing effect of hematopoietic Pin1 on the expressions of inflammatory cytokines such as tumor necrosis factorαand monocyte chemoattractant protein 1 through NF-κB activation, eventually leading to hepatic fibrosis. Finally, to distinguish the roles of hematopoietic or non-hematopoietic Pin1 in NASH development, mice lacking Pin1 in either non-hematopoietic or hematopoietic cells were produced by bone marrow transplantation between wild-type and Pin1 KO mice. The mice having non-hematopoietic Pin1 exhibited fat accumulation without liver fibrosis on the MCD diet. Thus, hepatic Pin1 appears to be directly involved in the fat accumulation in hepatocytes, while Pin1 in hematopoietic cells contribute to inflammation and fibrosis. In summary, this is the first study to demonstrate that Pin1 plays critical roles in NASH development. This report also raises the possibility that hepatic Pin1 inhibition to the appropriate level might provide a novel therapeutic strategy for NASH.
  Journal of Biological Chemistry 10/2012; · 4.77 Impact Factor
• Article: Valsartan, independently of AT1 receptor or PPARγ, suppresses LPS-induced macrophage activation and improves insulin resistance in cocultured adipocytes.

  Misaki Iwashita, Hideyuki Sakoda, Akifumi Kushiyama, Midori Fujishiro, Haruya Ohno, Yusuke Nakatsu, Toshiaki Fukushima, Sonoko Kumamoto, Yoshihiro Tsuchiya, Takako Kikuchi, Hiroki Kurihara, Hiroshi Akazawa, Issei Komuro, Hideaki Kamata, Fusanori Nishimura, Tomoichiro Asano
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  ABSTRACT: Macrophages are integrated into adipose tissues and interact with adipocytes in obese subjects, thereby exacerbating adipose insulin resistance. This study aimed to elucidate the molecular mechanism underlying the insulin-sensitizing effect of the angiotensin II receptor blocker (ARB) valsartan, as demonstrated in clinical studies. Insulin signaling, i.e., insulin receptor substrate-1 and Akt phosphorylations, in 3T3-L1 adipocytes was impaired markedly by treatment with tumor necrosis factor-α (TNFα) or in the culture medium of lipopolysaccharide (LPS)-stimulated RAW 264.7 murine macrophages, and valsartan had no effects on these impairments. However, in contrast, when cocultured with RAW 264.7 cells using a transwell system, the LPS-induced insulin signaling impairment in 3T3-L1 adipocytes showed almost complete normalization with coaddition of valsartan. Furthermore, valsartan strongly suppressed LPS-induced productions of cytokines such as interleukin (IL)-1β, IL-6, and TNFα with nuclear factor-κB activation and c-Jun NH(2)-terminal kinase phosphorylation in RAW 264.7 and primary murine macrophages. Very interestingly, this effect of valsartan was also observed in THP-1 cells treated with angiotensin II type 1 (AT1) siRNA or a peroxisome proliferator-activated receptor-γ (PPARγ) antagonist as well as macrophages from AT1a receptor-knockout mice. We conclude that valsartan suppresses the inflammatory response of macrophages, albeit not via PPARγ or the AT1a receptor. This suppression appears to secondarily improve adipose insulin resistance.
  AJP Endocrinology and Metabolism 11/2011; 302(3):E286-96. · 4.75 Impact Factor
• Article: Peptidyl-prolyl Cis/Trans Isomerase NIMA-interacting 1 Associates with Insulin Receptor Substrate-1 and Enhances Insulin Actions and Adipogenesis

  Yusuke Nakatsu, Hideyuki Sakoda, Akifumi Kushiyama, Jun Zhang, Hiraku Ono, Midori Fujishiro, Takako Kikuchi, Toshiaki Fukushima, Masayasu Yoneda, Haruya Ohno, [......], Hideaki Kamata, Fusanori Nishimura, Toshiaki Isobe, Takehide Ogihara, Hideki Katagiri, Yoshitomo Oka, Shin-ichiro Takahashi, Hiroki Kurihara, Takafumi Uchida, Tomoichiro Asano
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  ABSTRACT: Peptidyl-prolyl cis/trans isomerase NIMA-interacting 1 (Pin1) is a unique enzyme that associates with the pSer/Thr-Pro motif and catalyzes cis-trans isomerization. We identified Pin1 in the immunoprecipitates of overexpressed IRS-1 with myc and FLAG tags in mouse livers and confirmed the association between IRS-1 and Pin1 by not only overexpression experiments but also endogenously in the mouse liver. The analysis using deletion- and point-mutated Pin1 and IRS-1 constructs revealed the WW domain located in the N terminus of Pin1 and Ser-434 in the SAIN (Shc and IRS-1 NPXY binding) domain of IRS-1 to be involved in their association. Subsequently, we investigated the role of Pin1 in IRS-1 mediation of insulin signaling. The overexpression of Pin1 in HepG2 cells markedly enhanced insulin-induced IRS-1 phosphorylation and its downstream events: phosphatidylinositol 3-kinase binding with IRS-1 and Akt phosphorylation. In contrast, the treatment of HepG2 cells with Pin1 siRNA or the Pin1 inhibitor Juglone suppressed these events. In good agreement with these in vitro data, Pin1 knock-out mice exhibited impaired insulin signaling with glucose intolerance, whereas adenoviral gene transfer of Pin1 into the ob/ob mouse liver mostly normalized insulin signaling and restored glucose tolerance. In addition, it was also demonstrated that Pin1 plays a critical role in adipose differentiation, making Pin1 knock-out mice resistant to diet-induced obesity. Importantly, Pin1 expression was shown to be up-regulated in accordance with nutrient conditions such as food intake or a high-fat diet. Taken together, these observations indicate that Pin1 binds to IRS-1 and thereby markedly enhances insulin action, essential for adipogenesis.
  Journal of Biological Chemistry 06/2011; 286(23):20812-20822. · 4.77 Impact Factor
• Article: Peptidyl-prolyl cis/trans isomerase NIMA-interacting 1 associates with insulin receptor substrate-1 and enhances insulin actions and adipogenesis.

  Yusuke Nakatsu, Hideyuki Sakoda, Akifumi Kushiyama, Jun Zhang, Hiraku Ono, Midori Fujishiro, Takako Kikuchi, Toshiaki Fukushima, Masayasu Yoneda, Haruya Ohno, [......], Hideaki Kamata, Fusanori Nishimura, Toshiaki Isobe, Takehide Ogihara, Hideki Katagiri, Yoshitomo Oka, Shin-ichiro Takahashi, Hiroki Kurihara, Takafumi Uchida, Tomoichiro Asano
  [show abstract] [hide abstract]
  ABSTRACT: Peptidyl-prolyl cis/trans isomerase NIMA-interacting 1 (Pin1) is a unique enzyme that associates with the pSer/Thr-Pro motif and catalyzes cis-trans isomerization. We identified Pin1 in the immunoprecipitates of overexpressed IRS-1 with myc and FLAG tags in mouse livers and confirmed the association between IRS-1 and Pin1 by not only overexpression experiments but also endogenously in the mouse liver. The analysis using deletion- and point-mutated Pin1 and IRS-1 constructs revealed the WW domain located in the N terminus of Pin1 and Ser-434 in the SAIN (Shc and IRS-1 NPXY binding) domain of IRS-1 to be involved in their association. Subsequently, we investigated the role of Pin1 in IRS-1 mediation of insulin signaling. The overexpression of Pin1 in HepG2 cells markedly enhanced insulin-induced IRS-1 phosphorylation and its downstream events: phosphatidylinositol 3-kinase binding with IRS-1 and Akt phosphorylation. In contrast, the treatment of HepG2 cells with Pin1 siRNA or the Pin1 inhibitor Juglone suppressed these events. In good agreement with these in vitro data, Pin1 knock-out mice exhibited impaired insulin signaling with glucose intolerance, whereas adenoviral gene transfer of Pin1 into the ob/ob mouse liver mostly normalized insulin signaling and restored glucose tolerance. In addition, it was also demonstrated that Pin1 plays a critical role in adipose differentiation, making Pin1 knock-out mice resistant to diet-induced obesity. Importantly, Pin1 expression was shown to be up-regulated in accordance with nutrient conditions such as food intake or a high-fat diet. Taken together, these observations indicate that Pin1 binds to IRS-1 and thereby markedly enhances insulin action, essential for adipogenesis.
  Journal of Biological Chemistry 03/2011; 286(23):20812-22. · 4.77 Impact Factor
• Article: 4F2hc stabilizes GLUT1 protein and increases glucose transport activity.

  Haruya Ohno, Yusuke Nakatsu, Hideyuki Sakoda, Akifumi Kushiyama, Hiraku Ono, Midori Fujishiro, Yuichiro Otani, Hirofumi Okubo, Masayasu Yoneda, Toshiaki Fukushima, Yoshihiro Tsuchiya, Hideaki Kamata, Fusanori Nishimura, Hiroki Kurihara, Hideki Katagiri, Yoshitomo Oka, Tomoichiro Asano
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  ABSTRACT: Glucose transporter 1 (GLUT1) is widely distributed throughout various tissues and contributes to insulin-independent basal glucose uptake. Using a split-ubiquitin membrane yeast two-hybrid system, we newly identified 4F2 heavy chain (4F2hc) as a membrane protein interacting with GLUT1. Though 4F2hc reportedly forms heterodimeric complexes between amino acid transporters, such as LAT1 and LAT2, and regulates amino acid uptake, we investigated the effects of 4F2hc on GLUT1 expression and the associated glucose uptake. First, FLAG-tagged 4F2hc and hemagglutinin-tagged GLUT1 were overexpressed in human embryonic kidney 293 cells and their association was confirmed by coimmunoprecipitation. The green fluorescent protein-tagged 4F2hc and DsRed-tagged GLUT1 showed significant, but incomplete, colocalization at the plasma membrane. In addition, an endogenous association between GLUT1 and 4F2hc was demonstrated using mouse brain tissue and HeLa cells. Interestingly, overexpression of 4F2hc increased the amount of GLUT1 protein in HeLa and HepG2 cells with increased glucose uptake. In contrast, small interfering RNA (siRNA)-mediated 4F2hc gene suppression markedly reduced GLUT1 protein in both cell types, with reduced glucose uptake. While GLUT1 mRNA levels were not affected by overexpression or gene silencing of 4F2hc, GLUT1 degradation after the addition of cycloheximide was significantly suppressed by 4F2hc overexpression and increased by 4F2hc siRNA treatment. Taken together, these observations indicate that 4F2hc is likely to be involved in GLUT1 stabilization and to contribute to the regulation of not only amino acid but also glucose metabolism.
  AJP Cell Physiology 01/2011; 300(5):C1047-54. · 3.54 Impact Factor
• Article: Pin1 associates with and induces translocation of CRTC2 to the cytosol, thereby suppressing cAMP-responsive element transcriptional activity.

  Yusuke Nakatsu, Hideyuki Sakoda, Akifumi Kushiyama, Hiraku Ono, Midori Fujishiro, Nanao Horike, Masayasu Yoneda, Haruya Ohno, Yoshihiro Tsuchiya, Hideaki Kamata, Hidetoshi Tahara, Toshiaki Isobe, Fusanori Nishimura, Hideki Katagiri, Yoshitomo Oka, Toshiaki Fukushima, Shin-Ichiro Takahashi, Hiroki Kurihara, Takafumi Uchida, Tomoichiro Asano
  [show abstract] [hide abstract]
  ABSTRACT: Pin1 is a unique regulator, which catalyzes the conversion of a specific phospho-Ser/Thr-Pro-containing motif in target proteins. Herein, we identified CRTC2 as a Pin1-binding protein by overexpressing Pin1 with Myc and FLAG tags in mouse livers and subsequent purification of the complex containing Pin1. The association between Pin1 and CRTC2 was observed not only in overexpression experiments but also endogenously in the mouse liver. Interestingly, Ser(136) in the nuclear localization signal of CRTC2 was shown to be involved in the association with Pin1. Pin1 overexpression in HepG2 cells attenuated forskolin-induced nuclear localization of CRTC2 and cAMP-responsive element (CRE) transcriptional activity, whereas gene knockdown of Pin1 by siRNA enhanced both. Pin1 also associated with CRTC1, leading to their cytosol localization, essentially similar to the action of CRTC2. Furthermore, it was shown that CRTC2 associated with Pin1 did not bind to CREB. Taken together, these observations indicate the association of Pin1 with CRTC2 to decrease the nuclear CBP·CRTC·CREB complex. Indeed, adenoviral gene transfer of Pin1 into diabetic mice improved hyperglycemia in conjunction with normalizing phosphoenolpyruvate carboxykinase mRNA expression levels, which is regulated by CRE transcriptional activity. In conclusion, Pin1 regulates CRE transcriptional activity, by associating with CRTC1 or CRTC2.
  Journal of Biological Chemistry 10/2010; 285(43):33018-27. · 4.77 Impact Factor
• Article: Pin1 Associates with and Induces Translocation of CRTC2 to the Cytosol, Thereby Suppressing cAMP-responsive Element Transcriptional Activity

  Yusuke Nakatsu, Hideyuki Sakoda, Akifumi Kushiyama, Hiraku Ono, Midori Fujishiro, Nanao Horike, Masayasu Yoneda, Haruya Ohno, Yoshihiro Tsuchiya, Hideaki Kamata, Hidetoshi Tahara, Toshiaki Isobe, Fusanori Nishimura, Hideki Katagiri, Yoshitomo Oka, Toshiaki Fukushima, Shin-Ichiro Takahashi, Hiroki Kurihara, Takafumi Uchida, Tomoichiro Asano
  [show abstract] [hide abstract]
  ABSTRACT: Pin1 is a unique regulator, which catalyzes the conversion of a specific phospho-Ser/Thr-Pro-containing motif in target proteins. Herein, we identified CRTC2 as a Pin1-binding protein by overexpressing Pin1 with Myc and FLAG tags in mouse livers and subsequent purification of the complex containing Pin1. The association between Pin1 and CRTC2 was observed not only in overexpression experiments but also endogenously in the mouse liver. Interestingly, Ser136 in the nuclear localization signal of CRTC2 was shown to be involved in the association with Pin1. Pin1 overexpression in HepG2 cells attenuated forskolin-induced nuclear localization of CRTC2 and cAMP-responsive element (CRE) transcriptional activity, whereas gene knockdown of Pin1 by siRNA enhanced both. Pin1 also associated with CRTC1, leading to their cytosol localization, essentially similar to the action of CRTC2. Furthermore, it was shown that CRTC2 associated with Pin1 did not bind to CREB. Taken together, these observations indicate the association of Pin1 with CRTC2 to decrease the nuclear CBP·CRTC·CREB complex. Indeed, adenoviral gene transfer of Pin1 into diabetic mice improved hyperglycemia in conjunction with normalizing phosphoenolpyruvate carboxykinase mRNA expression levels, which is regulated by CRE transcriptional activity. In conclusion, Pin1 regulates CRE transcriptional activity, by associating with CRTC1 or CRTC2.
  Journal of Biological Chemistry 10/2010; 285(43):33018-33027. · 4.77 Impact Factor
• Article: IκBβ is a positive and negative regulator of NF-κB activity during inflammation.

  Hideaki Kamata, Yoshihiro Tsuchiya, Tomoichiro Asano
  Cell Research 10/2010; 20(11):1178-80. · 8.19 Impact Factor
• Article: Nuclear IKKbeta is an adaptor protein for IkappaBalpha ubiquitination and degradation in UV-induced NF-kappaB activation.

  Yoshihiro Tsuchiya, Tomoichiro Asano, Keiko Nakayama, Tomohisa Kato, Michael Karin, Hideaki Kamata
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  ABSTRACT: Proinflammatory cytokines activate NF-kappaB using the IkappaB kinase (IKK) complex that phosphorylates inhibitory proteins (IkappaBs) at N-terminal sites resulting in their ubiquitination and degradation in the cytoplasm. Although ultraviolet (UV) irradiation does not lead to IKK activity, it activates NF-kappaB by an unknown mechanism through IkappaBalpha degradation without N-terminal phosphorylation. Here, we describe an adaptor function of nuclear IKKbeta in UV-induced IkappaBalpha degradation. UV irradiation induces the nuclear translocation of IkappaBalpha and association with IKKbeta, which constitutively interacts with beta-TrCP through heterogeneous ribonucleoprotein-U (hnRNP-U) leading to IkappaBalpha ubiquitination and degradation. Furthermore, casein kinase 2 (CK2) and p38 associate with IKKbeta and promote IkappaBalpha degradation by phosphorylation at C-terminal sites. Thus, nuclear IKKbeta acts as an adaptor protein for IkappaBalpha degradation in UV-induced NF-kappaB activation. NF-kappaB activated by the nuclear IKKbeta adaptor protein suppresses anti-apoptotic gene expression and promotes UV-induced cell death.
  Molecular cell 08/2010; 39(4):570-82. · 14.61 Impact Factor
• Article: Nuclear IKKβ Is an Adaptor Protein for IκBα Ubiquitination and Degradation in UV-Induced NF-κB Activation

  Yoshihiro Tsuchiya, Tomoichiro Asano, Keiko Nakayama, Kato, Tomohisa, Michael Karin, Hideaki Kamata, ヨシヒロ ツチヤ, トモイチロウ アサノ, Tomoichirō Asano, ケイコ ナカヤマ, トモヒサ カトウ, Tomohisa Katō, ヒデアキ カマタ, 佳弘 土谷, 知一郎 浅野, 啓子 中山, 友久 加藤, 英明 鎌田
  [show abstract] [hide abstract]
  ABSTRACT: Proinflammatory cytokines activate NF-κB using the IκB kinase (IKK) complex that phosphorylates inhibitory proteins (IκBs) at N-terminal sites resulting in their ubiquitination and degradation in the cytoplasm. Although ultraviolet (UV) irradiation does not lead to IKK activity, it activates NF-κB by an unknown mechanism through IκBα degradation without N-terminal phosphorylation. Here, we describe an adaptor function of nuclear IKKβ in UV-induced IκBα degradation. UV irradiation induces the nuclear translocation of IκBα and association with IKKβ, which constitutively interacts with β-TrCP through heterogeneous ribonucleoprotein-U (hnRNP-U) leading to IκBα ubiquitination and degradation. Furthermore, casein kinase 2 (CK2) and p38 associate with IKKβ and promote IκBα degradation by phosphorylation at C-terminal sites. Thus, nuclear IKKβ acts as an adaptor protein for IκBα degradation in UV-induced NF-κB activation. NF-κB activated by the nuclear IKKβ adaptor protein suppresses anti-apoptotic gene expression and promotes UV-induced cell death.