AUTHORS
Jun Zhang , Li Fu , Jing Zhang , Bo Zhou , Yanrong Tang , Zhenzhen Zhang , Tongqing Gu
ABSTRACT
Objective
Evidence has shown that microRNA (miR)-122–5p is a diagnostic biomarker of acute myocardial infarction. Here, we aimed to uncover the functions of miR-122–5p in the pathological process of myocardial ischemia-reperfusion injury (MI/RI).
Methods
An MI/RI model was established by left anterior descending coronary artery ligation in mice. The levels of miR-122–5p, suppressor of cytokine signaling-1 (SOCS1), phosphorylation of Janus kinase 2 (p-JAK2), and signal transducers and activators of transcription (p-STAT3) in the myocardial tissues of mice were measured. Downregulated miR-122–5p or upregulated SOCS1 recombinant adenovirus vectors were injected into mice before MI/RI modeling. The cardiac function, inflammatory response, myocardial infarction area, pathological damage, and cardiomyocyte apoptosis in the myocardial tissues of mice were evaluated. Cardiomyocytes were subjected to hypoxia/reoxygenation (H/R) injury and cardiomyocyte biological function was tested upon transfection of miR-122–5p inhibitor. The target relation between miR-122–5p and SOCS1 was evaluated.
Results
miR-122–5p expression and p-JAK2 and p-STAT3 expression were high, and SOCS1 expression was low in the myocardial tissues of MI/RI mice. Decreasing miR-122–5p or increasing SOCS1 expression inactivated the JAK2/STAT3 pathway to alleviate MI/RI by improving cardiac function and reducing inflammatory reaction, myocardial infarction area, pathological damage, and cardiomyocyte apoptosis in mice. Silencing of SOCS1 reversed depleted miR-122–5p-induced cardioprotection for MI/RI mice. In vitro experiments revealed that the downregulation of miR-122–5p induced proliferative, migratory, and invasive capabilities of H/R cardiomyocytes while inhibiting apoptosis. Mechanically, SOCS1 was a target gene of miR-122–5p.
Conclusion
Our study summarizes that inhibition of miR-122–5p induces SOCS1 expression, thereby relieving MI/RI in mice.