Abstract
Large tumor suppressor kinase 2 (Lats2) is a member of the Hippo pathway, a critical regulator of organ size. Since Lats2 activity may trigger mitochondrial dysfunction, a key pathogenic factor in acute myocardial infarction (AMI), this study sought to investigate whether Lats2 deletion confers cardioprotection in AMI. AMI was induced in cardiomyocyte-specific Lats2 knockout (Lats2Cko) and control (Lats2flox) mice. Twenty-eight days after AMI surgery, myocardial performance and mitochondrial homeostasis were impaired in Lats2floxmice. In contrast, Lats2Cko mice exhibited markedly preserved cardiac structure and contraction/relaxation activity, decreased fibrosis, reduced circulating cardiac injury biomarker levels, and enhanced cardiomyocyte viability. Consistent with these findings, siRNA-mediated Lats2 silencing sustained mitochondrial respiration and inhibited apoptosis in hypoxia-treated HL-1 cardiomyocytes. Notably, Lats2 deficiency inhibited AMI/hypoxia-related mitochondrial fission and inactivated STING/p65 signaling by preventing hypoxia-induced release of mtDNA into the cytosol. Accordingly, pharmacological reactivation of STING signaling abolished the cardioprotective effects of Lats2 ablation. Those data suggest that AMI-induced Lats2 upregulation is associated with impaired cardiomyocyte viability and function resulting from enhanced mitochondrial fission, mtDNA release, and STING/p65 pathway activation.