Connexin 43 in cardiomyocyte mitochondria and its increase by ischemic preconditioning
Connexin 43 in cardiomyocyte mitochondria and its increase by ischemic preconditioning
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DOI：
10.1016/j.cardiores.2005.04.014
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发表时间：
2005-08-01
影响因子：
10.8
通讯作者：
Schulz, R
中科院分区：
文献类型：
--
作者：
Boengler, K;Dodoni, G;Schulz, R
目的：连接蛋白43（Cx43）参与缺血预处理（IP）减少梗死面积的过程；然而，其潜在的保护机制尚不清楚。由于线粒体被认为参与了IP的保护作用，本研究分析了Cx43是否定位于心肌细胞的线粒体，以及这种定位是否受IP影响。
方法和结果：对从大鼠、小鼠、猪和人心脏分离的线粒体提取物进行的蛋白质印迹分析表明存在Cx43。这些提取物未受其他细胞区室标志物的污染。通过流式细胞术分选（用线粒体追踪红和Cx43双重染色）以及免疫电子显微镜和共聚焦显微镜也证实了Cx43在线粒体的定位。为了研究Cx43在IP中的作用，在90分钟低流量缺血结束时，从猪心肌缺血的前壁（AW）和对照的后壁（PW）分离线粒体，不进行（n = 13）或进行（n = 13）先前的10分钟缺血和15分钟再灌注的预处理循环。在IP作用下，AW的线粒体Cx43/腺嘌呤核苷酸转运体比值比PW高3.4 ± 0.7倍，而在未预处理的心肌中该比值保持不变（1.1 ± 0.2，p < 0.05）。线粒体Cx43蛋白水平的升高迅速发生，因为在离体大鼠心脏中，经过两个5分钟缺血/再灌注循环，已经检测到线粒体Cx43增加到基线的262 ± 63%。
结论：这些数据表明Cx43定位于心肌细胞线粒体，并且IP增强了这种线粒体定位。（c）2005年欧洲心脏病学会。由爱思唯尔出版公司出版。保留所有权利。
Objective: Connexin 43 (Cx43) is involved in infarct size reduction by ischemic preconditioning (IP); the underlying mechanism of protection, however, is unknown. Since mitochondria have been proposed to be involved in IP's protection, the present study analyzed whether Cx43 is localized at mitochondria of cardiomyocytes and whether such localization is affected by IP.Methods and results: Western blot analysis on mitochondrial preparations isolated from rat, mouse, pig, and human hearts showed the presence of Cx43. The preparations were not contaminated with markers for other cell compartments. The localization of Cx43 to mitochondria was also confirmed by FACS sorting (double staining with NlitoTracker Red and Cx43) and immuno-electron and confocal rnicroscopy. To study the role of Cx43 in IP, mitochondria were isolated from the ischemic anterior wall (AW) and the control posterior wall (PW) of pig myocardium at the end of 90 min low-flow ischemia without (n = 13) or with (n = 13) a preceding preconditioning cycle of 10 min ischemia and 15 min reperfusion. With IP, the mitochondrial Cx43/adenine nucleotide transporter ratio was 3.4 +/- 0.7 fold greater in AW than in PW, whereas the ratio remained unchanged in non-preconditioned myocardium (1.1 +/- 0.2, p < 0.05). The enhancement of the mitochondrial Cx43 protein level occurred rapidly, since an increase of mitochondrial Cx43 was already detected with two cycles of 5 min ischemia/reperfusion in isolated rat hearts to 262 +/- 63% of baseline.Conclusion: These data demonstrate that Cx43 is localized at cardiomyocyte mitochondria and that IP enhances such mitochondrial localization. (c) 2005 European Society of Cardiology. Published by Elsevier B.V All rights reserved.