Voltage-dependent anion channel 2 modulates resting Ca2+ sparks, but not action potential-induced Ca2+ signaling in cardiac myocytes
Voltage-dependent anion channel 2 modulates resting Ca2+ sparks, but not action potential-induced Ca2+ signaling in cardiac myocytes
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DOI：
10.1016/j.ceca.2010.12.004
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发表时间：
2011-02-01
期刊：
影响因子：
4
通讯作者：
Woo, Sun-Hee
中科院分区：
文献类型：
--
作者：
Subedi, Krishna Prasad;Kim, Joon-Chul;Woo, Sun-Hee
电压依赖性阴离子通道(VDAC)是一种主要存在于线粒体膜外膜的成孔蛋白，被认为是运输钙离子的物质。在这项研究中，我们利用慢病毒敲除(KD)技术和二维共聚焦钙成像技术，在永生化的自律性成人心房细胞HL-1上研究了2型VDAC(VDAC2)在心脏钙信号和钙火花中的可能作用。我们通过Western印迹分析证实了VDAC2蛋白在心室、心房和HL-1细胞中的高表达。靶向VDAC2的慢病毒感染HL-1细胞后，VDAC2蛋白的表达水平下降到接近10%。比较野生型(WT)和VDAC2KD细胞的自律性钙瞬变，发现钙的大小、衰变和搏动频率没有显著变化。转瞬即逝。VDAC2 KD不改变咖啡因(10 MM)诱导的肌浆网(SR)钙离子释放。然而，有趣的是，在静息条件下，VDAC2KD显著增加了单个钙火花的强度、宽度和持续时间，而火花的频率没有改变。VDAC2KD显著延迟通透性HL-1细胞在人工钙脉冲作用下线粒体的钙摄取。这些结果提示，VDAC2在静息状态下可能促进线粒体钙摄取，限制钙离子火花扩张，而不调节火花的激活，从而为VDAC2在心脏局部钙离子中的功能作用提供了证据。发信号。(C)2010爱思唯尔有限公司。保留所有权利。
Voltage-dependent anion channels (VDACs) are pore forming proteins predominantly found in the outer mitochondrial membrane and are thought to transport Ca2+. In this study, we have investigated the possible role of type 2 VDAC (VDAC2) in cardiac Ca2+ signaling and Ca2+ sparks using a lentiviral knock-down (KD) technique and two-dimensional confocal Ca2+ imaging in immortalized autorhythmic adult atrial cells, HL-1. We confirmed high expression of VDAC2 protein in ventricular, atrial, and HL-1 cells using Western blot analysis. Infection of HL-1 cells with VDAC2-targeting lentivirus reduced the level of VDAC2 protein to similar to 10%. Comparisons of autorhythmic Ca2+ transients between wild-type (WT) and VDAC2 KD cells showed no significant change in the magnitude, decay, and beating rate of the Ca2+. transients. Caffeine (10 mM)-induced Ca2+ release, which indicates sarcoplasmic reticulum (SR) Ca2+ content, was not altered by VDAC2 KD. Interestingly, however, the intensity, width, and duration of the individual Ca2+ sparks were significantly increased by VDAC2 KD in resting conditions, with no change in the frequency of sparks. VDAC2 KD significantly delayed mitochondrial Ca2+ uptake during artificial Ca2+ pulses in permeabilized HL-1 cells. These results suggest that VDAC2 may facilitate mitochondrial Ca2+ uptake and restrict Ca2+ spark expansion without regulating activations of sparks under resting conditions, thereby providing evidence on the functional role of VDAC2 in cardiac local Ca2+. signaling. (C) 2010 Elsevier Ltd. All rights reserved.