Regulation of calcium-permeable TRPV2 channel by insulin in pancreatic beta-cells.
Regulation of calcium-permeable TRPV2 channel by insulin in pancreatic beta-cells.
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DOI：
10.2337/db08-0862
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发表时间：
2009-01
期刊：
影响因子：
7.7
通讯作者：
Kojima, Itaru
中科院分区：
文献类型：
--
作者：
Hisanaga, Etsuko;Nagasawa, Masahiro;Ueki, Kobjiro;Kulkarni, Rohit N.;Mori, Masatomo;Kojima, Itaru
目的：胰腺β细胞表达钙离子通透性阳离子通道TRPV2。我们研究了TRPV2在β-细胞中的调控和功能。研究设计与方法-通过将融合有绿色荧光蛋白的TRPV2或含有c-Myc标记的TRPV2在胞外区导入，检测TRPV2在MIN6细胞和培养的小鼠β-细胞中的转位。通过监测Fura-2荧光检测钙离子内流。结果：在未受刺激的MIN6细胞中，TRPV2主要分布在胞浆中。外源性胰岛素可诱导TRPV2易位和插入质膜。与这些观察结果一致的是，胰岛素增加了钙内流，这可被TRPV2的抑制剂曲尼司特或用shRNA敲除TRPV2所抑制。高浓度的葡萄糖也可以诱导TRPV2的易位，这种移位可以被奈非地平、二氮嗪和生长抑素等阻断葡萄糖诱导的胰岛素分泌的药物所阻断。抑制胰岛素受体可减弱胰岛素诱导的TRPV2易位。同样，在β细胞系中没有观察到胰岛素对TRPV2转位的影响，该细胞系来源于β细胞特异性胰岛素受体基因敲除小鼠的胰岛。抑制TRPV2或加入曲尼司特可显著抑制高浓度葡萄糖诱导的胰岛素分泌。同样，血清和葡萄糖诱导的细胞生长可被曲尼司特或TRPV2基因敲除所抑制。最后，在培养的小鼠β细胞中观察到胰岛素诱导的TRPV2易位，并且敲除TRPV2可以减少葡萄糖诱导的胰岛素分泌。结论：TRPV2受胰岛素调节，参与了胰岛素对β细胞的自分泌作用。
OBJECTIVE—Calcium-permeable cation channel TRPV2 is expressed in pancreatic β-cells. We investigated regulation and function of TRPV2 in β-cells. RESEARCH DESIGN AND METHODS—Translocation of TRPV2 was assessed in MIN6 cells and cultured mouse β-cells by transfecting TRPV2 fused to green fluorescent protein or TRPV2 containing c-Myc tag in the extracellular domain. Calcium entry was assessed by monitoring fura-2 fluorescence. RESULTS—In MIN6 cells, TRPV2 was observed mainly in cytoplasm in an unstimulated condition. Addition of exogenous insulin induced translocation and insertion of TRPV2 to the plasma membrane. Consistent with these observations, insulin increased calcium entry, which was inhibited by tranilast, an inhibitor of TRPV2, or by knockdown of TRPV2 using shRNA. A high concentration of glucose also induced translocation of TRPV2, which was blocked by nefedipine, diazoxide, and somatostatin, agents blocking glucose-induced insulin secretion. Knockdown of the insulin receptor attenuated insulin-induced translocation of TRPV2. Similarly, the effect of insulin on TRPV2 translocation was not observed in a β-cell line derived from islets obtained from a β-cell–specific insulin receptor knockout mouse. Knockdown of TRPV2 or addition of tranilast significantly inhibited insulin secretion induced by a high concentration of glucose. Likewise, cell growth induced by serum and glucose was inhibited by tranilast or by knockdown of TRPV2. Finally, insulin-induced translocation of TRPV2 was observed in cultured mouse β-cells, and knockdown of TRPV2 reduced insulin secretion induced by glucose. CONCLUSIONS—TRPV2 is regulated by insulin and is involved in the autocrine action of this hormone on β-cells.
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Kowase, T;Nakazato, Y;Kojima, I
通讯作者：
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56.9
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