CREG protects from myocardial ischemia/reperfusion injury by regulating myocardial autophagy and apoptosis

Aims: Human cellular repressor of E1A-stimulated genes (CREG) is a secreted glycoprotein that regulates tissue and cell homeostasis and has been shown to antagonize heart fibrosis,which indicates a potential protective effect of CREG against cardiomyocyte chronic damage. However, little is known about the role of CREG inmyocardial tissue acute injury, in this study,we aimed to investigate the role of CREG in myocardial ischemia/reperfusion (MI/R) in- jury and clarify themechanism of action. Methods and results: Wild-type Creg (Creg+/+), heterozygous Creg (Creg+/−) mice and mice pretreated with infusionof recombinant 0.3 mg/kg·d CREGprotein (reCreg+/+)were subjected to 30minof left ascending coronary ischemia and 24 h of reperfusion. Evan's Blue-triphenyl- tetrazolium chloride (TTC) solution and echocardiography analysis were used to evaluate the effects of CREG on MI/R mice. The underlying mechanisms were further determined by cultured myocardial cells in vitro. Our findings revealed that the level of CREG protein inmouse hearts was significantly decreased after mice were subjected toMI/R. Moreover, Creg+/−mice had larger infarction size 2 h after reperfusion andworse cardiac function 28 days afterMI/R injury compared to that in Creg+/+ mice. However, reCreg+/+ mice couldmaintain CREG at a high level even after MI/R injury, and mitigated infarction size and improved cardiac function significantly. In Creg+/− mice, myocardial autophagy was dysfunctional characterized by accumulation of LC3A and p62, while apoptotic cell number increase was detected by cleaved caspase-3 blotting and TUNEL staining. Conversely, decreased apoptosis and activated autophagy were detected in reCreg+/+mice.Furthermore,chloroquine,akind of autophagy blocker,was used to demonstrate recombinant CREGprotectedcardiomyocytes against apoptosismediatedby activating autophagy bothin vivoand in vitro. Finally, we found CREGwas involved into lysosomal protein transfer and improve cellular autophagy. Conclusion: CREG protects heart againstMI/R injury-induced cardiomyocytes apoptosis by activating lysosomal autophagy.