LINC-PINT Activates the Mitogen-Activated Protein Kinase Pathway to Promote Acute Myocardial Infarction by Regulating miR-208a-3p.

Abstract

This study is performed to explore the differential expression of long intergenic non-coding-p53 induced non-coding transcript, miR-208a-3p and JUN in acute myocardial infarction (AMI) and their potential mechanisms. Methods and Results: Gene Expression Omnibus, R software, Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) analysis were used for analyzing the differentially expressed genes (DEGs) and pathways. The differential expressions of LINC-PINT and miR-208a-3p were examined by qRT-PCR. The expressions of JUN and the mitogen-activated protein kinase (MAPK) pathway-related proteins were analyzed by Western blot. The triphenyltetrazolium chloride (TTC) staining and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL) staining methods were used to measure the myocardial infarction size and tissue apoptosis respectively. The targeted relationships between miR-208a-3p and LINC-PINT or JUN were confirmed using a dual luciferase reporter assay. DEGs were significantly enriched in the MAPK signaling pathway. LINC-PINT could sponge miR-208a-3p, which targeted and regulated JUN. LINC-PINT and JUN were confirmed to be overexpressed in AMI tissues. Silencing LINC-PINT and JUN could exert a protective influence against AMI. The expression of miR-208a-3p was significantly decreased in AMI tissues, and miR-208a-3p reduced myocardial ischemia-reperfusion injury and apoptosis. Downregulation of LINC-PINT facilitated miR-208a-3p expression and suppressed the protein level of JUN, contributing to the inactivation of the MAPK pathway in the AMI tissues and thus generating protective effects. Knockdown of LINC-PINT inactivated the MAPK pathway by releasing miR-208a-3p and suppressing the JUN, protecting the injury during the process of AMI.