Oxidative stress promotes redistribution of TRPM2 channels to the plasma membrane in hepatocytes
Oxidative stress promotes redistribution of TRPM2 channels to the plasma membrane in hepatocytes
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DOI：
10.1016/j.bbrc.2018.07.132
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发表时间：
2018-09-10
影响因子：
3.1
通讯作者：
Rychkov, Grigori Y.
中科院分区：
文献类型：
--
作者：
Kheradpezhouh, Ehsan;Zhou, Fiona H.;Rychkov, Grigori Y.
瞬时受体电位Melastatin(TRPM)2是一种非选择性钙离子通透性阳离子通道，是瞬时受体电位(Trp)通道家族的成员。TRPM2具有独特的门控特性；它被细胞内ADP-核糖(ADPR)激活，而Ca~(2+)在通道激活中扮演着重要的辅助因子的角色，增加了TRPM2对ADPR的敏感性。TRPM2在大鼠和小鼠肝细胞中高度表达，已被证明与氧化应激诱导的细胞死亡和扑热息痛过量所致的肝损伤有关。然而，调节肝细胞TRPM2通道活性的机制还不是很清楚。本文对TRPM2蛋白在肝细胞中的定位进行了研究。结果表明，在正常情况下的大鼠肝细胞中，TRPM2蛋白主要定位于细胞内。这是通过使用TRPM2和质膜(PM)特异性抗体和免疫荧光的共聚焦显微镜以及随后的生物素化研究和Western blotting来确定的。有趣的是，在用过氧化氢或扑热息痛处理的肝细胞中，与PM共定位的TRPM2的数量与未处理的细胞相比显著增加。结论：在氧化应激条件下，TRPM2向PM的转运可能有助于介导肝细胞内钙超载的正反馈机制。皇冠版权所有(C)2018由爱思唯尔公司出版。保留所有权利。
Transient Receptor Potential Melastatin (TRPM) 2 is a non-selective Ca2+ permeable cation channel and a member of the Transient Receptor Potential (TRP) channel family. TRPM2 has unique gating properties; it is activated by intracellular ADP-ribose (ADPR), whereas Ca2+ plays a role of an important co-factor in channel activation, increasing TRPM2 sensitivity to ADPR. TRPM2 is highly expressed in rat and mouse hepatocytes, where it has been shown to contribute to oxidative stress-induced cell death and liver damage due to paracetamol-overdose. The mechanisms regulating the activity of TRPM2 channels in hepatocytes, however, are not well understood. In this paper, we investigate the localisation of TRPM2 protein in hepatocytes. The presented results demonstrate that in rat hepatocytes under normal conditions, most of the TRPM2 protein is localised intracellularly. This was determined by confocal microscopy using TRPM2-and plasma membrane (PM)-specific antibodies and immunofluorescence, and biotinylation studies followed by western blotting. Interestingly, in hepatocytes treated with either H2O2 or paracetamol, the amount of TRPM2 co-localised with PM is significantly increased, compared to the untreated cells. It is concluded that trafficking of TRPM2 to the PM could potentially contribute to a positive feedback mechanism mediating Ca2+ overload in hepatocytes under conditions of oxidative stress. Crown Copyright (C) 2018 Published by Elsevier Inc. All rights reserved.