Adiponectin exerts cardioprotection against ischemia/reperfusion injury partially via calreticulin mediated anti-apoptotic and anti-oxidative actions
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The underlying mechanisms of cardioprotection of adiponectin (APN) against ischemia/reperfusion (I/R) injury remain largely unknown. The present study aimed to investigate whether calreticulin (CRT) mediated APN’s cardioprotection against I/R injury. We inhibited mice cardiac CRT expression via intra-myocardial injection of CRT SiRNA, performed transient LAD ligation, measured the cardiac function, apoptosis and oxidative stress to identify CRT’s effects on cardioprotective actions of APN against I/R injury in vivo. LDH release and expression of CRT were measured in neonatal cardiomyocytes (NCM) subjected to simulated I/R (SI/R) and APN. CRT specific SiRNA was also utilized in vitro. CRT inhibition partially blunted cardioprotection of APN against I/R injury (evidenced by left ventricular ejection fraction and myocardial infarct size). It also blunted APN’s function against I/R induced apoptosis and oxidative stress (evidenced by TUNEL positive staining and reactive oxygen species production). In addition, SI/R increased LDH release, and administration of APN attenuated SI/R-induced cell death significantly. However, neither SI/R nor APN altered CRT expression in NCM. Inhibition of CRT expression blunted cardioprotective action of APN against SI/R induced apoptotic events (evidenced by TUNEL positive staining, LDH release and Caspase 3 activity). Furthermore, CRT inhibition significantly blunted APN’s anti-oxidative action (evidenced by gp91phox expression and superoxide generation). However, CRT inhibition did not attenuate AMPK phosphorylation by APN administration in NCM. Therefore, these novel findings strongly indicate that APN exerts cardioprotective effects against I/R injury partially via CRT mediated anti-apoptotic and anti-oxidative actions.
KeywordsAdiponectin Apoptosis Calreticulin Myocardial ischemia/reperfusion Oxidative stress
This work was supported by National Natural Science Foundation of China (81422004, 81500263, 81470480, 81470477, 81100137, 81100081), China Postdoctoral Science Foundation (2015M572681), National High-tech R&D Program of China (2014AA020514, 2015AA020919), and Technological New Star Program of Shaanxi Province (2014KJXX-56).
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Conflict of interest
The authors declare no conflicts of interest.