Rapid electrical stimulation causes alterations in cardiac intercellular junction proteins of cardiomyocytes
Rapid electrical stimulation causes alterations in cardiac intercellular junction proteins of cardiomyocytes
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快速电刺激导致心肌细胞的心脏细胞间连接蛋白改变
DOI：
10.1152/ajpheart.00653.2013
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Masafumi Yano
中科院分区：
文献类型：
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作者：
Tadamitsu Nakashima;Tomoko Ohkusa;Yoko Okamoto;Masaaki Yoshida;Jong-Kook Lee;Yoichi Mizukami;Masafumi Yano
细胞间连接包含两个复合体，黏附连接(AJ)和连接蛋白(CX)缝隙连接(GJS)。GJS为细胞间的电流流动提供了途径。AJS介导正常的机械耦合，对GJS的稳定性起着重要作用。我们研究了快速电刺激(RES)对心脏细胞间连接的影响，特别是β-连环蛋白和Cx43的变化。我们还研究了阻断血管紧张素Ⅱ受体对细胞间连接重塑的影响。断头处死新生大鼠，制备、培养心肌细胞，给予Res处理。我们使用了实时荧光定量聚合酶链式反应、蛋白质印迹分析和免疫组织化学方法。细胞外电位标测系统检测细胞外电导特性。60min后，心肌细胞Cx43蛋白表达明显增加。30min后，β-catenin在细胞总组分中的表达明显增加。β-连环蛋白作为T细胞因子/淋巴细胞增强因子结合因子转录激活剂在细胞核中的表达水平在10min后显著增加，其降解受糖原合成酶-3β调控。Res作用60min后，传导速度明显增加。奥美沙坦阻止了Res的大部分这些影响。我们发现，被激活的MAPKs磷酸化并抑制β-连环蛋白降解的磷酸化糖原合成酶-3 MAPK-3的DNA增加，被奥美沙坦减弱。β-连环蛋白的变化先于Cx43GJ的重塑，可能在GJS的形成和稳定中起重要作用。奥美沙坦可能通过β-连环蛋白信号通路调节细胞间连接重构，从而成为一种新的上游心律失常治疗方法。
The intercellular junctions contain two complexes, adhesion junctions (AJ) and connexin (Cx) gap junctions (GJs). GJs provide the pathway for intercellular current flow. AJs mediate normal mechanical coupling and play an important role in the stability of GJs. We investigated the effects of rapid electrical stimulation (RES) on cardiac intercellular junctions, especially β-catenin and Cx43 alterations. We also studied the effects of ANG II receptor blockade on intercellular junction remodeling. Neonatal rats were euthanized by decapitation, and cardiomyocytes were prepared, cultured, and subjected to RES. We used real-time PCR, western blot analysis, and immunohistochemical methods. Conduction properties were examined by an extracellular potential mapping system. Cx43 protein expression in cardiomyocytes was significantly increased after 60 min. β-Catenin expression in the total cell fraction was significantly increased after 30 min. The expression level of β-catenin in the nucleus, which functions as a T cell factor/lymphocyte enhancer binding factor transcriptional activator of Cx43 with its degradation regulated by glycogen synthase kinase-3β, was dramatically increased after 10 min. Conduction velocity was increased significantly by RES for 60 min. Olmesartan prevented most these effects of RES. We showed an increase of phosphorylated glycogen synthase kinase-3β, which is phosphorylated by activated MAPKs and inhibits β-catenin degradation, was attenuated by olmesartan. The changes in β-catenin precede Cx43 GJ remodeling and might play an important role in the formation and stability of GJs. Olmesartan might be a new upstream arrhythmia therapy by modulating intercellular junction remodeling through the β-catenin signaling pathway.