Reconstruction of pancreatic beta cell in non-islet cell -Analysis of signal transduction in first phase of insulin secretion

非胰岛细胞中胰腺β细胞的重建-胰岛素分泌第一阶段的信号转导分析

• 批准号: 11671130
• 负责人: MIYAMURA Nobuhiro
• 金额: $ 0.58万
• 依托单位: KUMAMOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11671130/
• 关键词: NON-ISLETS CELL; GLUT2; GLUCOKINASE; PHOSPHOLIPASE C; K±ATP CHANNEL; VDCC; IP3 RECEPTOR; 糖尿病; 膵β細胞; インスリン分泌応答機構; インスリン分泌調節遺伝子; ブドウ糖認識機構

U73122, an inhibitor of phospholipase C, suppressed glucose-induced insulin secretion from isolated rat islets or mouse insulinoma MIN6 cells in static condition. In perifusion study, however, U73122 suppressed second phase of glucose-induced insulin secretion from rat islets. Although acute suppression of insulin release from rat islets was observed after negative stepwise glucose stimulation, delayed suppression was observed in case of MIN6 cells or AtT20HI-GLUT2-GK cells. Expression of two isoforms of phospholipase C (PLCβ, PLCγ) was observed in rat islets, MIN6 cells and AtT20HI-GLUT2-GK cells. Expression of PLCδ was observed in rat islets and MIN6 cells, but not in AtT20HI-GLUT2-GK cells. Furthermore, expression of type III inositol-1,4,5-triphosphate receptor was not observed in AtT20HI-GLUT2-GK cells. These data suggested that transfection of at least two genes coding PLCδ and type III IP3 receptor was required to reconstruct physiological insulin secretion machinery. Blockade of ATP-sensitive potassium channel (K^+ATP) or activation of voltage-dependent calcium channel (VDCC) induced insulin secretion from AtT20HI-GLUT2-GK cells. Opening of K^+ATP or blockade of VDCC suppressed glucose-induced insulin secretion from the cells. These indicated functional K^+ATP and VDCC were expressed in AtT20HI-GLUT2-GK cells.

磷脂酶C抑制剂U 73122在静态条件下抑制葡萄糖诱导的大鼠胰岛或小鼠胰岛素瘤MIN 6细胞的胰岛素分泌。然而，在灌流研究中，U 73122抑制了大鼠胰岛葡萄糖诱导的胰岛素分泌的第二相。尽管在负逐步葡萄糖刺激后观察到大鼠胰岛胰岛素释放的急性抑制，但在MIN 6细胞或AtT 20 HI-GLUT 2-GK细胞的情况下观察到延迟抑制。在大鼠胰岛、MIN 6细胞和AtT 20 HI-GLUT 2-GK细胞中观察到磷脂酶C的两种亚型（PLCβ、PLCγ）的表达。PLCδ在大鼠胰岛和MIN 6细胞中有表达，而在AtT 20 HI-GLUT 2-GK细胞中无表达。此外，在AtT 20 HI-GLUT 2-GK细胞中未观察到III型肌醇-1，4，5-三磷酸受体的表达。这些数据表明，转染至少两个编码PLCδ和III型IP 3受体的基因是重建生理性胰岛素分泌机制所必需的。ATP敏感性钾通道（K^+ATP）阻断或电压依赖性钙通道（VDCC）激活可诱导AtT 20 HI-GLUT 2-GK细胞分泌胰岛素。开放K^+ATP或阻断VDCC可抑制葡萄糖诱导的细胞胰岛素分泌。这表明AtT 20 HI-GLUT 2-GK细胞表达功能性K^+ATP和VDCC。