Irisin ameliorates septic cardiomyopathy via inhibiting DRP1-related mitochondrial fission and normalizing the JNK-LATS2 signaling pathway.

Irisin plays a protective effect in acute and chronic myocardial damage, but its role in septic cardiomyopathy is unclear. The aim of our study was to explore the in vivo and in vitro effects of irisin using an LPS-induced septic cardiomyopathy model. Our results demonstrated that irisin treatment attenuated LPS-mediated cardiomyocyte death and myocardial dysfunction. At the molecular level, LPS application was associated with mitochondrial oxidative injury, cardiomyocyte ATP depletion and caspase-related apoptosis activation. In contrast, the irisin treatment sustained mitochondrial function by inhibiting DRP1-related mitochondrial fission and the reactivation of mitochondrial fission impaired the protective action of irisin on inflammation-attacked mitochondria and cardiomyocytes. Additionally, we found that irisin modulated DRP1-related mitochondrial fission through the JNK-LATS2 signaling pathway. JNK activation and/or LATS2 overexpression abolished the beneficial effects of irisin on LPS-mediated mitochondrial stress and cardiomyocyte death. Altogether, our results illustrate that LPS-mediated activation of DRP1-related mitochondrial fission through the JNK-LATS2 pathway participates in the pathogenesis of septic cardiomyopathy. Irisin could be used in the future as an effective therapy for sepsis-induced myocardial depression because it corrects DRP1-related mitochondrial fission and normalizes the JNK-LATS2 signaling pathway.