CIRKIL Exacerbates Cardiac Ischemia/Reperfusion Injury by Interacting With Ku70
Hongwen Xiao, Mingyu Zhang, Hao Wu, Jiaxu Wu, Xiaoxi Hu, Xinyu Pei, Danyang Li, Lu Zhao, Qi Hua, Bo Meng, Xiaowen Zhang, Lili Peng, Xiaoling Cheng, Zhuoyun Li, Wanqi Yang, Qi Zhang, Yang Zhang, Yanjie Lu, Zhenwei Pan
Abstract
Background: Ku70 participates in several pathological processes through mediating repair of DNA double-strand breaks. Our previous study has identified a highly conserved long noncoding RNA cardiac ischemia reperfusion associated Ku70 interacting lncRNA (CIRKIL) that was upregulated in myocardial infarction. The study aims to investigate whether CIRKIL regulates myocardial ischemia/reperfusion (I/R) through binding to Ku70. Methods: CIRKIL transgenic and knockout mice were subjected to 45-minute ischemia and 24-hour reperfusion to establish myocardial I/R model. RNA pull-down and RNA immunoprecipitation assay were used to detect the interaction between CIRKIL and Ku70. Results: The expression of CIRKIL was increased in I/R myocardium and H 2 O 2 -treated cardiomyocytes. Overexpression of CIRKIL increased the expression of γH 2 A.X, a specific marker of DNA double-strand breaks and aggravated cardiomyocyte apoptosis, whereas knockdown of CIRKIL produced the opposite changes. Transgenic overexpression of CIRKIL aggravated cardiac dysfunction, enlarged infarct area, and worsened cardiomyocyte damage in I/R mice. Knockout of CIRKIL alleviated myocardial I/R injury. Mechanistically, CIRKIL directly bound to Ku70 to subsequently decrease nuclear translocation of Ku70 and impair DNA double-strand breaks repair. Concurrent overexpression of Ku70 mitigated CIRKIL overexpression-induced myocardial I/R injury. Furthermore, knockdown of human CIRKIL significantly suppressed cell damage induced by H 2 O 2 in adult human ventricular cardiomyocytes and human induced pluripotent stem cell-derived cardiomyocytes. Conclusions: CIRKIL is a detrimental factor in I/R injury acting via regulating nuclear translocation of Ku70 and DNA double-strand breaks repair. Thus, CIRKIL might be considered as a novel molecular target for the treatment of cardiac conditions associated with I/R injury.