Background: MicroRNAs (miRNAs) have been implicated in ischemia-reperfusion injury and ischemic preconditioning. Opioid pre- and postconditioning have powerful protective effects on the heart, but it is still not known whether miRNAs are involved in opioid-induced cardioprotection. The present study was designed to investigate the role of miRNAs in morphine preconditioning (MPC)-induced cardioprotection.
Methods: MiRNA microarray analysis was performed to examine the differentially expressed miRNAs caused by MPC in adult rat cardiomyocytes. A dual-luciferase reporter assay was performed to confirm the direct regulation of miR-133b-5p on the target gene Fas. MiR-133b-5p mimic or inhibitor was separately transfected into myocardial H9c2 cells to examine the role of miR-133b-5p in morphine-induced cardioprotection.
Results: MPC protected adult rat cardiomyocytes against hypoxia/reoxygenation (H/R) injury by reducing cell injury and death. MiRNA microarray data showed that a total of 39 miRNAs were differentially expressed after MPC treatment. A Dual-luciferase reporter assay confirmed that miR-133b-5p directly targets the Fas gene. After H/R injury, the decrease in miR-133b-5p and a contemporaneous rise in Fas mRNA and protein levels in adult rat cardiomyocytes were prevented by MPC treatment. In H9c2 cardiomyocytes, overexpression of miR-133b-5p reduced H/R-induced cell injury and apoptosis by inhibiting Fas expression. Knockdown of miR-133b-5p blocked morphine-mediated cardioprotection by reducing miR-133b-5p levels while enhancing the expression of Fas mRNA and protein.
Conclusions: MPC causes a change in miRNA expression in rat cardiomyocytes. Morphine may protect cardiomyocytes against H/R injury through upregulation of miR-133b-5p by targeting Fas.
Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.