Department of Anesthesiology, Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China.
Department of Anesthesiology, Wuhan No. 1 Hospital, Wuhan, Hubei 430022, China.
Chin Med J (Engl). 2023 Jun 5;136(11):1349-1357. doi: 10.1097/CM9.0000000000002618.
Dysfunction of the gap junction channel protein connexin 43 (Cx43) contributes to myocardial ischemia/reperfusion (I/R)-induced ventricular arrhythmias. Cx43 can be regulated by small ubiquitin-like modifier (SUMO) modification. Protein inhibitor of activated STAT Y (PIASy) is an E3 SUMO ligase for its target proteins. However, whether Cx43 is a target protein of PIASy and whether Cx43 SUMOylation plays a role in I/R-induced arrhythmias are largely unknown.
Male Sprague-Dawley rats were infected with PIASy short hairpin ribonucleic acid (shRNA) using recombinant adeno-associated virus subtype 9 (rAAV9). Two weeks later, the rats were subjected to 45 min of left coronary artery occlusion followed by 2 h reperfusion. Electrocardiogram was recorded to assess arrhythmias. Rat ventricular tissues were collected for molecular biological measurements.
Following 45 min of ischemia, QRS duration and QTc intervals statistically significantly increased, but these values decreased after transfecting PIASy shRNA. PIASy downregulation ameliorated ventricular arrhythmias induced by myocardial I/R, as evidenced by the decreased incidence of ventricular tachycardia and ventricular fibrillation, and reduced arrythmia score. In addition, myocardial I/R statistically significantly induced PIASy expression and Cx43 SUMOylation, accompanied by reduced Cx43 phosphorylation and plakophilin 2 (PKP2) expression. Moreover, PIASy downregulation remarkably reduced Cx43 SUMOylation, accompanied by increased Cx43 phosphorylation and PKP2 expression after I/R.
PIASy downregulation inhibited Cx43 SUMOylation and increased PKP2 expression, thereby improving ventricular arrhythmias in ischemic/reperfused rats heart.
缝隙连接通道蛋白连接蛋白 43（Cx43）的功能障碍导致心肌缺血/再灌注（I/R）诱导的室性心律失常。Cx43 可通过小泛素样修饰物（SUMO）修饰进行调节。蛋白抑制物激活 STAT Y（PIASy）是其靶蛋白的 E3 SUMO 连接酶。然而，Cx43 是否是 PIASy 的靶蛋白，以及 Cx43 SUMO 化在 I/R 诱导的心律失常中是否起作用，在很大程度上尚不清楚。
雄性 Sprague-Dawley 大鼠用重组腺相关病毒 9（rAAV9）感染 PIASy 短发夹 RNA（shRNA）。两周后，大鼠进行 45 分钟左冠状动脉阻塞，然后再灌注 2 小时。记录心电图以评估心律失常。收集大鼠心室组织进行分子生物学测量。
缺血 45 分钟后，QRS 持续时间和 QTc 间期显著增加，但转染 PIASy shRNA 后这些值降低。PIASy 下调改善了心肌 I/R 诱导的室性心律失常，表现为室性心动过速和室颤的发生率降低，心律失常评分降低。此外，心肌 I/R 显著诱导 PIASy 表达和 Cx43 SUMO 化，伴随着 Cx43 磷酸化和 plakophilin 2（PKP2）表达降低。此外，PIASy 下调后，I/R 后 Cx43 SUMO 化明显减少，Cx43 磷酸化和 PKP2 表达增加。
PIASy 下调抑制 Cx43 SUMO 化并增加 PKP2 表达，从而改善缺血/再灌注大鼠心脏的室性心律失常。
