Long non-coding RNA-AK138945 regulates myocardial ischemia-reperfusion injury via the miR-1-GRP94 signaling pathway

Objective Myocardial ischemia-reperfusion injury (MIRI) is one of the leading causes of death from cardiovascular disease in humans, especially in individuals exposed to cold environments. Long non-coding RNAs (lncRNAs) regulate MIRI through multiple mechanisms.This study explored the regulatory effect of lncRNA-AK138945 on myocardial ischemia-reperfusion injury and its mechanism. Methods In vivo , 8- to 12-weeks-old C57BL/6 male mice underwent ligation of the left anterior descending coronary artery for 50 minutes followed by reperfusion for 48 hours. In vitro , the primary cultured neonatal mouse ventricular cardiomyocytes (NMVCs) were treated with 100 μmol/L hydrogen peroxide (H 2 O 2 ). The knockdown of lncRNA-AK138945 was evaluated to detect cardiomyocyte apoptosis, and a glucose-regulated, endoplasmic reticulum stress-related protein 94 (GRP94) inhibitor was used to detect myocardial injury. Results We found that the expression level of lncRNA-AK138945 was reduced in MIRI mouse heart tissue and H 2 O 2 -treated cardiomyocytes. Moreover, the proportion of apoptosis in cardiomyocytes increased after lncRNA-AK138945 was silenced. The expression level of Bcl2 protein was decreased, and the expression level of Bad, Caspase 9 and Caspase 3 protein was increased. Our further study found that miR-1a-3p is a direct target of lncRNA-AK138945, after lncRNA-AK138945 was silenced in cardiomyocytes, the expression level of miR-1a-3p was increased while the expression level of its downstream protein GRP94 was decreased. Interestingly, treatment with a GRP94 inhibitor (PU-WS13) intensified H 2 O 2 -induced cardiomyocyte apoptosis. After overexpression of FOXO3, the expression levels of lncRNA-AK138945 and GRP94 were increased, while the expression levels of miR-1a-3p were decreased. Conclusion LncRNA-AK138945 inhibits GRP94 expression by regulating miR-1a-3p, leading to cardiomyocyte apoptosis. The transcription factor Forkhead Box Protein O3 (FOXO3) participates in cardiomyocyte apoptosis induced by endoplasmic reticulum stress through up-regulation of lncRNA-AK138945.