Inhibiting miR-22 Alleviates Cardiac Dysfunction by Regulating Sirt1 in Septic Cardiomyopathy

High morbidity and mortality are the most typical characteristics of septic cardiomyopathy. We aimed to reveal the role of miR-22 in septic cardiomyopathy and to explore the underlying mechanisms. miR-22 cardiac-specific knockout (miR-22(cKO)) mice and miR-22 cardiac-specific transgenic (miR-22(cOE)) mice were subjected to a cecal ligation and puncture (CLP) operation, while a sham operation was used in the control group. The echocardiogram results suggested that miR-22(cKO) CLP mice cardiac dysfunction was alleviated. The serum LDH and CK-MB were reduced in the miR-22(cKO) CLP mice. As expected, there was reduced apoptosis, increased autophagy and alleviated mitochondrial dysfunction in the miR-22(cKO) CLP mice, while it had contrary role in the miR-22(cOE) group. Inhibiting miR-22 promoted autophagy by increasing the LC3II/GAPDH ratio and decreasing the p62 level. Additionally, culturing primary cardiomyocytes with lipopolysaccharide (LPS) simulated sepsis-induced cardiomyopathy in vitro. Inhibiting miR-22 promoted autophagic flux confirmed by an increased LC3II/GAPDH ratio and reduced p62 protein level under bafilomycin A1 conditions. Knocking out miR-22 may exert a cardioprotective effect on sepsis by increasing autophagy and decreasing apoptosis via sirt1. Our results revealed that targeting miR-22 may become a new strategy for septic cardiomyopathy treatment.

Automated summary

In septic cardiomyopathy, miR-22 plays an important role by promoting autophagy and reducing apoptosis. Inhibiting miR-22 can exert a cardioprotective effect, potentially becoming a new strategy for treating septic cardiomyopathy.