Mitochondrial Cx43 hemichannels contribute to mitochondrial calcium entry and cell death in the heart
Mitochondrial Cx43 hemichannels contribute to mitochondrial calcium entry and cell death in the heart
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DOI：
10.1007/s00395-017-0618-1
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发表时间：
2017-05-01
影响因子：
9.5
通讯作者：
Leybaert, Luc
中科院分区：
文献类型：
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作者：
Gadicherla, Ashish Kumar;Wang, Nan;Leybaert, Luc
线粒体连接蛋白43（Cx43）在反复暴露于短时间非致死性缺血/再灌注（称为缺血预处理）引起的心脏细胞保护中起关键作用。Cx43还形成钙（Ca 2+）渗透性半通道，其可能潜在地导致线粒体Ca 2+过载和细胞死亡。在这里，我们研究了Cx43在促进线粒体Ca 2+进入中的作用，并研究了其下游后果。为此，我们使用了各种连接蛋白靶向肽与细胞外（Gap 26）和细胞内（Gap 19，RRNYRRNY）Cx43结构域相互作用，并测试了它们对线粒体染料和Ca 2+摄取，质膜和线粒体Cx43通道的电生理特性以及细胞损伤/细胞死亡的影响。我们在离体小鼠心肌肌膜下线粒体中的研究结果表明，Cx43形成半通道，有助于Ca 2+进入，并可能触发通透性转换和细胞损伤/死亡。RRNYRRNY在所有测定中显示出最强的作用，并抑制质膜以及线粒体Cx43半通道。RRNYRRNY还在离体心脏缺血-再灌注研究中显著减小梗死面积。这些结果表明，Cx43有助于线粒体Ca 2+稳态，并参与触发细胞损伤/死亡途径，可以被RRNYRRNY肽抑制。
Mitochondrial connexin 43 (Cx43) plays a key role in cardiac cytoprotection caused by repeated exposure to short periods of non-lethal ischemia/reperfusion, a condition known as ischemic preconditioning. Cx43 also forms calcium (Ca2+)-permeable hemichannels that may potentially lead to mitochondrial Ca2+ overload and cell death. Here, we studied the role of Cx43 in facilitating mitochondrial Ca2+ entry and investigated its downstream consequences. To that purpose, we used various connexin-targeting peptides interacting with extracellular (Gap26) and intracellular (Gap19, RRNYRRNY) Cx43 domains, and tested their effect on mitochondrial dye- and Ca2+-uptake, electrophysiological properties of plasmalemmal and mitochondrial Cx43 channels, and cell injury/cell death. Our results in isolated mice cardiac subsarcolemmal mitochondria indicate that Cx43 forms hemichannels that contribute to Ca2+ entry and may trigger permeability transition and cell injury/death. RRNYRRNY displayed the strongest effects in all assays and inhibited plasma membrane as well as mitochondrial Cx43 hemichannels. RRNYRRNY also strongly reduced the infarct size in ex vivo cardiac ischemia-reperfusion studies. These results indicate that Cx43 contributes to mitochondrial Ca2+ homeostasis and is involved in triggering cell injury/death pathways that can be inhibited by RRNYRRNY peptide.