Anoctamin 1 (Ano1) is required for glucose-induced membrane potential oscillations and insulin secretion by murine β-cells
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- 作者：Raphaël Crutzen ; Myrna Virreira…
- 关键词：Chloride ; TMEM16A ; Islet
- 刊名：Pfl¨¹gers Archiv - European Journal of Physiology
- 出版年：2016
- 出版时间：April 2016
- 年：2016
- 卷：468
- 期：4
- 页码：573-591
- 全文大小：2,998 KB
- 刊物主题：Human Physiology;
- 出版者：Springer Berlin Heidelberg
- ISSN：1432-2013
文摘
Anions such as Cl− and HCO3 − are well known to play an important role in glucose-stimulated insulin secretion (GSIS). In this study, we demonstrate that glucose-induced Cl− efflux from β-cells is mediated by the Ca2+-activated Cl− channel anoctamin 1 (Ano1). Ano1 expression in rat β-cells is demonstrated by reverse transcriptase–polymerase chain reaction, western blotting, and immunohistochemistry. Typical Ano1 currents are observed in whole-cell and inside-out patches in the presence of intracellular Ca++: at 1 μM, the Cl− current is outwardly rectifying, and at 2 μM, it becomes almost linear. The relative permeabilities of monovalent anions are NO3 − (1.83 ± 0.10) > Br− (1.42 ± 0.07) > Cl− (1.0). A linear single-channel current–voltage relationship shows a conductance of 8.37 pS. These currents are nearly abolished by blocking Ano1 antibodies or by the inhibitors 2-(5-ethyl-4-hydroxy-6-methylpyrimidin-2-ylthio)-N-(4-(4-methoxyphenyl)thiazol-2-yl)acetamide (T-AO1) and tannic acid (TA). These inhibitors induce a strong decrease of 16.7-mM glucose-stimulated action potential rate (at least 87 % on dispersed cells) and a partial membrane repolarization with T-AO1. They abolish or strongly inhibit the GSIS increment at 8.3 mM and at 16.7 mM glucose. Blocking Ano1 antibodies also abolish the 16.7-mM GSIS increment. Combined treatment with bumetanide and acetazolamide in low Cl− and HCO3 − media provokes a 65 % reduction in action potential (AP) amplitude and a 15-mV AP peak repolarization. Although the mechanism triggering Ano1 opening remains to be established, the present data demonstrate that Ano1 is required to sustain glucose-stimulated membrane potential oscillations and insulin secretion.