Investigation For Molecular Mechanism Of Insulin Resistance In Transgenic Mice Expressing A Mutant Shp2

表达突变型Shp2的转基因小鼠胰岛素抵抗的分子机制研究

• 批准号: 10671062
• 负责人: MAEGAWA Hiroshi
• 金额: $ 2.11万
• 依托单位: Shiga University Of Medical Science
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10671062/
• 关键词: Protein-Tyrosine Phosphatase; SHP-2; Transgenic Mice; Insulin Resistance; Protein phosphatase

To elucidate roles of SHP-2, we generated transgenic (Tg) mice expressing a dominant negative mutant lacking PTPase domain (DPTP). On examining 2 lines of Tg mice identified by Southern blot, the transgene product was expressed in skeletal muscle liver and adipose tissues and insulin-induced association of insulin receptor substrate (IRS) 1 with endogenous SHP-2 was inhibited, confirming that DPTP has a dominant negative property. The intraperitoneal glucose loading test demonstrated an increase in blood glucose levels in Tg mice. Plasma insulin levels in Tg mice after 4 h fasting were 3 times greater with comparable blood glucose levels. To estimate insulin sensitivity by a constant glucose, insulin and somatostatin infusion, steady state blood glucose levels were higher, suggesting the presence of insulin resistance. Furthermore we observed the impairment of insulin-stimulated glucose uptake in muscle and adipocytes in the presence of physiological concentrations of insulin. Moreover, tyrosine-phosphorylation of IRS-1 and stimulation of phosphatidylinositol 3-kinase and Akt kinase activities by insulin were attenuated in muscle and liver. These results indicate that the inhibition of endogenous SHP-2 function by the overexpression of a dominant negative mutant may lead to impaired insulin sensitivity of glucose metabolism and thus SHP-2 may function to modulate insulin signaling in target tissues and these Tg mice are a unique model to investigate molecular mechanism for insulin resistance.

为了阐明SHP-2的作用，我们制造了转基因（Tg）小鼠，表达缺乏PTPase结构域（DPTP）的显性负突变体。通过Southern blot检测鉴定的2株Tg小鼠，转基因产物在骨骼肌、肝脏和脂肪组织中表达，胰岛素诱导的胰岛素受体底物（IRS） 1与内源性SHP-2的关联被抑制，证实DPTP具有显性负性。腹腔内葡萄糖负荷试验显示Tg小鼠血糖水平升高。空腹4小时后，Tg小鼠的血浆胰岛素水平比血糖水平高3倍。通过持续的葡萄糖、胰岛素和生长抑素输注来估计胰岛素敏感性，稳态血糖水平较高，表明存在胰岛素抵抗。此外，我们观察到胰岛素刺激的肌肉和脂肪细胞的葡萄糖摄取在胰岛素的生理浓度存在的损害。此外，在肌肉和肝脏中，胰岛素对IRS-1酪氨酸磷酸化和磷脂酰肌醇3-激酶和Akt激酶活性的刺激减弱。这些结果表明，过表达显性负突变体抑制内源性SHP-2功能可能导致糖代谢胰岛素敏感性受损，因此SHP-2可能在靶组织中调节胰岛素信号传导，这些Tg小鼠是研究胰岛素抵抗分子机制的独特模型。

项目成果

Egawa K, Maegawa H, Shimizu S, Morino K, Nishio Y, Bryer-Ash, M, Cheung AT, Kolls JK, Kikkawa R and Kashiwagi A.: "Protein Tyrosine Phosphatase-1B Negatively Regulates Insulin Signaling in L6 Myocytes and Fao Hepatoma Cells."J.Biol.Chem.. (in press).

Ekawa K、Maekawa H、Shimizu S、Morino K、Nishio Y、Bryer-Ash、M、Cheung AT、Kolls JK、Kikkawa R 和 Kashiwagi A.：“蛋白质酪氨酸磷酸酶 1B 负调节 L6 肌细胞和 Fao 肝癌中的胰岛素信号传导

Morino K,Maegawa H, et al.: "Insulin-induced JNK activation is negatively regulated by protein kinase C δ"Endocrinology. (in press).

Morino K、Maekawa H 等人：“胰岛素诱导的 JNK 激活受到蛋白激酶 C δ 的负调节”内分泌学（正在出版）。

Fujita T,Maegawa H, et al: "Opposite Regulation of Tyrosine-phosphorylation of p130^<Cas> by Insulin and Insulin-like Growth Factor I"J.Biochem, Tokyo. 123. 1111-1116 (1998)

Fujita T，Maekawa H，等人：“胰岛素和胰岛素样生长因子 I 对 p130^<Cas> 酪氨酸磷酸化的相反调节”J.Biochem，东京。

Maegawa H, et al: "Expression of a dominant negative SHP-2 in transgenic mice induces insulin resistance"J. Biol. Chem.. 274. 30236-30243 (1999)

Maekawa H 等人：“转基因小鼠中显性失活 SHP-2 的表达会诱导胰岛素抵抗”J.

Obata T,Maegawa H, et al: "High-glucose-induced abnormal Epidermal growth factor signaling"J.Biochem, Tokyo. 123. 813-820 (1998)

Obata T、Maekawa H 等人：“高葡萄糖诱导的异常表皮生长因子信号传导”J.Biochem，东京。