A differential role of macrophage TRPM2 channels in Ca2+ signaling and cell death in early responses to H2O2
A differential role of macrophage TRPM2 channels in Ca2+ signaling and cell death in early responses to H2O2
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巨噬细胞 TRPM2 通道在 Ca2 信号传导和 H2O2 早期反应中细胞死亡中的不同作用
DOI：
10.1152/ajpcell.00390.2012
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发表时间：
2013-07-01
影响因子：
5.5
通讯作者：
Jiang, Lin-Hua
中科院分区：
文献类型：
--
作者：
Zou, Jie;Ainscough, Justin F.;Jiang, Lin-Hua
H_2O_2等活性氧物种通过激活多聚(ADPR)聚合酶(PARP)升高胞浆内钙离子浓度([Ca~(2+)](C))并导致细胞死亡，这也代表了H_2O_2作为存在于质膜上的钙离子通透通道或细胞内钙释放通道激活瞬时受体电位--褪黑素相关2(TRPM2)通道的主要机制。本研究以小鼠腹膜巨噬细胞RAW264.7和分化的THP-1细胞为研究对象，探讨巨噬细胞内TRPM2通道在介导细胞死亡和钙信号转导中的作用及其机制。H_2O_2可引起细胞内[Ca~(2+)](C)的显著升高，而且在体温下这种对Ca~(2+)的反应明显强于室温。PARP抑制剂PJ-34可强烈抑制H_2O_2诱导的Ca~(2+)反应，而胞外Ca~(2+)的清除可在很大程度上阻止H_2O_2诱导的Ca~(2+)反应。此外，在分离的TRPM2(-/-)小鼠巨噬细胞中，H_2O_2诱导的[Ca~(2+)](C)升高被完全消除。过氧化氢以持续时间和浓度依赖的方式降低巨噬细胞的活力。PJ-34和TRPM2通道缺陷可显著减轻H_2O_2诱导的细胞死亡，但仍显着且持续。综上所述，这些结果表明，巨噬细胞中的TRPM2通道作为细胞表面钙离子通透通道，介导了钙离子内流，并构成了主要的钙信号机制，但在H_2O_2暴露的早期细胞死亡中起着有限的，尽管重要的作用。
Reactive oxygen species such as H2O2 elevates the cytosolic Ca2+ concentration ([Ca2+](c)) and causes cell death via poly(ADPR) polymerase (PARP) activation, which also represents the primary mechanism by which H2O2 activate the transient receptor potential melastatin-related 2 (TRPM2) channel as a Ca2+-permeable channel present in the plasma membrane or an intracellular Ca2+-release channel. The present study aimed to define the contribution and mechanisms of the TRPM2 channels in macrophage cells in mediating Ca2+ signaling and cell death during initial response to H2O2, using mouse peritoneal macrophage, RAW264.7, and differentiated THP-1 cells. H2O2 evoked robust increases in the [Ca2+](c), and such Ca2+ responses were significantly greater at body temperature than room temperature. H2O2-induced Ca2+ responses were strongly inhibited by pretreatment with PJ-34, a PARP inhibitor, and largely prevented by removal of extracellular Ca2+. Furthermore, H2O2-induced increases in the [Ca2+](c) were completely abolished in macrophage cells isolated from trpm2(-/-) mice. H2O2 reduced macrophage cell viability in a duration- and concentration-dependent manner. H2O2-induced cell death was significantly attenuated by pretreatment with PJ-34 and TRPM2 channel deficiency but remained significant and persistent. Taken together, these results show that the TRPM2 channel in macrophage cells functions as a cell surface Ca2+-permeable channel that mediates Ca2+ influx and constitutes the principal Ca2+ signaling mechanism but has a limited, albeit significant, role in cell death during early exposure to H2O2.