CPNE3 interaction with RACK1 protects against myocardial ischemia/reperfusion injury

Copine 3 (CPNE3) and receptor for activated C kinase 1 (RACK1) have been determined to be risk factors for patients with acute myocardial ischemia/reperfusion (I/R). The present study aimed to evaluate the role of CPNE3 and its interaction with RACK1 in myocardial (I/R) injury. Reverse transcription-quantitative PCR (RT-qPCR) and western blotting were performed to detect CPNE3 and RACK1 expression levels in H9c2 cells before and after the transfection of CPNE3 overexpression plasmid or small interfering RNA-RACK1. Cell viability was detected using a Cell Counting Kit-8 assay, and immunoprecipitation assays were performed to determine the interaction between CPNE3 and RACK1. A commercial kit was used to examine lactate dehydrogenase (LDH) levels. The expression levels of inflammatory cytokines were detected via RT-qPCR and western blotting. Cell apoptosis was assessed via TUNEL staining and western blotting. The results demonstrated that the expression levels of CPNE3 and RACK1 were decreased in hypoxia/reoxygenation (H/R)-induced H9c2 cardiomyocytes, which was consistent with the expression levels observed in the myocardial I/R injury rat model. It was found that CPNE3 overexpression upregulated RACK1 expression, increased cell viability and suppressed the release of LDH in H/R-induced H9c2 cells. Furthermore, CPNE3 overexpression inhibited the release of inflammatory cytokines and decreased cell apoptosis in H/R-induced cardiomyocytes by activating RACK1 expression. The present study suggested that CPNE3 served an important role in preventing I/R injury by interacting with RACK1, providing novel insight into the prevention of myocardial I/R injury, as well as the treatment and care of patients with myocardial I/R.