G protein-coupled receptor (GPR)40-dependent potentiation of insulin secretion in mouse islets is mediated by protein kinase D1
G protein-coupled receptor (GPR)40-dependent potentiation of insulin secretion in mouse islets is mediated by protein kinase D1
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DOI：
10.1007/s00125-012-2650-x
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发表时间：
2012-10-01
期刊：
影响因子：
8.2
通讯作者：
Poitout, V.
中科院分区：
文献类型：
--
作者：
Ferdaoussi, M.;Bergeron, V.;Poitout, V.
长链脂肪酸对G蛋白偶联受体（GPR）40的激活增强了来自胰腺β细胞的葡萄糖刺激的胰岛素分泌（GSIS），并且GPR 40激动剂处于用于2型糖尿病治疗的临床开发中。GPR 40与G蛋白亚基G α（q/11）偶联，但下游激活的信号级联尚不清楚。本研究旨在确定脂肪酸依赖于GPR 40增强GSIS的机制。在野生型（WT）和Gpr 40（-/-）小鼠的胰岛动态灌流和静态孵育中评估了葡萄糖、油酸或二酰甘油（DAG）响应的胰岛素分泌。通过鬼笔环肽染色和落射荧光观察丝状肌动蛋白（F-肌动蛋白）的解聚。通过药理学和分子生物学方法研究了蛋白激酶D（PKD）和蛋白激酶C δ在GPR 40介导的GSIS增强中的作用。油酸增强GSIS的第二阶段，这种作用在很大程度上依赖于GPR 40。因此，油酸盐在WT中诱导快速的F-肌动蛋白重构，但在Gpr 40（-/-）胰岛中不诱导。外源性DAG增强WT和Gpr 40（-/-）胰岛中的GSIS。在WT胰岛中，油酸诱导残基Ser-744/748和Ser-916的PKD磷酸化，但不诱导Gpr 40（-/-）胰岛的PKD磷酸化。重要的是，油酸诱导的F-actin解聚和GSIS增强作用在PKD 1的药理学抑制或Prkd 1的缺失后消失。我们得出结论，脂肪酸激活GPR 40下游的信号级联反应涉及PKD 1的激活、F-actin解聚和第二相胰岛素分泌的增强。这些结果提供了重要的信息GPR 40的作用机制，一种新的药物靶点2型糖尿病。
Activation of the G protein-coupled receptor (GPR)40 by long-chain fatty acids potentiates glucose-stimulated insulin secretion (GSIS) from pancreatic beta cells, and GPR40 agonists are in clinical development for type 2 diabetes therapy. GPR40 couples to the G protein subunit G alpha(q/11) but the signalling cascade activated downstream is unknown. This study aimed to determine the mechanisms of GPR40-dependent potentiation of GSIS by fatty acids.Insulin secretion in response to glucose, oleate or diacylglycerol (DAG) was assessed in dynamic perifusions and static incubations in islets from wild-type (WT) and Gpr40 (-/-) mice. Depolymerisation of filamentous actin (F-actin) was visualised by phalloidin staining and epifluorescence. Pharmacological and molecular approaches were used to ascertain the roles of protein kinase D (PKD) and protein kinase C delta in GPR40-mediated potentiation of GSIS.Oleate potentiates the second phase of GSIS, and this effect is largely dependent upon GPR40. Accordingly, oleate induces rapid F-actin remodelling in WT but not in Gpr40 (-/-) islets. Exogenous DAG potentiates GSIS in both WT and Gpr40 (-/-) islets. Oleate induces PKD phosphorylation at residues Ser-744/748 and Ser-916 in WT but not Gpr40 (-/-) islets. Importantly, oleate-induced F-actin depolymerisation and potentiation of GSIS are lost upon pharmacological inhibition of PKD1 or deletion of Prkd1.We conclude that the signalling cascade downstream of GPR40 activation by fatty acids involves activation of PKD1, F-actin depolymerisation and potentiation of second-phase insulin secretion. These results provide important information on the mechanisms of action of GPR40, a novel drug target for type 2 diabetes.