Nicotinic Agonist Inhibits Cardiomyocyte Apoptosis in CVB3-Induced Myocarditis via α 3 β 4-nAChR/PI3K/Akt-Dependent Survivin Upregulation

• Published in: Oxidative medicine and cellular longevity Vol. 2019; pp. 9496419 - 13
• Main Authors: Li, Ping, Yan, Yaoyao, Shi, Youyang, Cheng, Bo, Zhan, Yi, Wang, Qiaoyu, Ye, Qiaofang, Weng, Yawen, Wu, Tingting, Wu, Rongzhou
• Format: Journal Article
• Language: English
• Published: United States 01.01.2019
• Subjects: Animals; Apoptosis; Humans; Male; Mice; Myocarditis - drug therapy; Myocytes, Cardiac - drug effects; Nicotinic Agonists - pharmacology; Nicotinic Agonists - therapeutic use; Phosphatidylinositol 3-Kinases - metabolism; Proto-Oncogene Proteins c-akt - metabolism; Rats; Survivin; Up-Regulation
• ISSN: 1942-0900; 1942-0994
• DOI: 10.1155/2019/9496419

Cardiomyocyte apoptosis is critical for the development of coxsackievirus B3- (CVB3-) induced myocarditis, which is a common cardiac disease that may result in heart failure or even sudden death. Previous studies have associated CVB3-induced apoptosis with the downregulation of antiapoptotic proteins. Here, attempts were made to examine whether nicotinic acetylcholine receptors (nAChRs), especially 3 4-nAChRs, were a novel therapeutic antiapoptotic target via the activation of survivin, a strong antiapoptotic protein, in viral myocarditis (VMC). In the present study, we demonstrated that nAChRs, 3 4-nAChR subunits in particular, were present and upregulated in CVB3-infected neonatal rat cardiomyocytes (NRC) and H9c2 cells by RT-qPCR. The function of 3 4-nAChRs was next examined using its specific blocker -CTX AuIB in vitro. The results of the TUNEL assay and western blot experiments showed that the block of 3 4-nAChRs abrogated nicotine-mediated protection of NRC from CVB3-induced apoptosis, and this effect displayed a substantial correlation with the protein expressions of pAkt, survivin, and Cleaved Caspase-3. Hence, the involvement of the PI3K/Akt pathway was further verified by LY294002, a selective inhibitor of PI3K. As a result, nicotine-mediated induction of pAkt and survivin was abolished by LY294002; meanwhile, apoptotic NRC were increased accompanied by an increase of Cleaved Caspase-3 expression. Regarding CVB3-infected BALB/c mice, the -CTX AuIB- and LY294002-treated groups had a lower survival rate, deteriorative ventricular systolic function, and more severe inflammation than the nicotine-treated group and the modulation of pAkt, survivin, and Cleaved Caspase-3 protein expressions was similar to that in CVB3-infected NRC. In addition, we found that a nicotinic agonist reduced CVB3 replication in a dose-dependent manner in vitro, which indicates that nAChR activation may serve as a possible protection mechanism of CVB3-induced myocarditis. Our study demonstrated that 3 4-nAChR subunits are essential in the nicotine-mediated antiapoptotic effect of protecting cardiomyocytes from CVB3-induced apoptosis in vivo and in vitro. This protection correlated with the PI3K/Akt pathway and the inducement of the antiapoptotic protein survivin. A combination of these mechanisms serves as a novel protective response to treat viral myocarditis.