Mesenchymal Stem Cells-Derived Exosomal microRNA-182-5p Downregulates Gasdermin D and Ameliorates Myocardial Ischemia/Reperfusion Injury

Objective: Exosomes contain abundant microRNAs (miRNAs/miRs) and play an intermediary role in cell-to-cell communications. Recently, miR-182-5p was found to have cardioprotective effects against ischemia/reperfusion (I/R) injury. However, whether exosomes delivering miR-182-5p functions post I/R injury remains unknown. The present study aimed at exploring whether exosomal miR-182-5p would protect against myocardial I/R injury-induced pyroptosis. Methods: I/R mouse model was developed by left anterior descending coronary artery occlusion. Myocardial cell exposed to hypoxia/reoxygenation (H/R) was also used as in vitro I/R model. Binding relationship between miR-182-5p and gasdermin D (GSDMD) was evaluated by dual-luciferase reporter gene assay. MiR-182-5p and GSDMD loss- and gain-of-function experiments were conducted to explore the effects of miR-182-5p via mesenchymal stem cells (MSCs)-derived exosomes on I/R- or H/R- induced pyroptosis, cell viability, pyroptosis-related proteins and inflammatory cytokines, reactive oxygen species (ROS) production, and lactate dehydrogenase (LDH) release in vitro and in vivo. Results: miR-182-5p expression was decreased while GSDMD increased in I/R-injured myocardial tissues. In addition, miR-182-5p targeted and reduced GSDMD expression. Overexpression of GSDMD facilitated H/R-induced myocardial cell pyroptosis and inhibited viability, accompanied by increased LDH release, ROS production, and levels of pyroptosis markers. Importantly, transfer of miR-182-5p-loaded exosomes derived from MSCs downregulated GSDMD in H/R-exposed cardiomyocytes. Moreover, miR-182-5p-loaded exosome injection significantly improved cardiac function and decreased myocardial infarction and cell damage in I/R mice. Conclusions: Collectively, results from the present study demonstrated that transfer of miR-182-5p-loaded exosomes derived from MSCs downregulated GSDMD and alleviated I/R-induced pyroptosis in cardiomyocytes. Funding Statement: This study was supported by the National Natural Science Foundation of China (81600232), the Key Projects of Education Department of Sichuan Province (17ZA0183), Municipal-School Cooperative Scientific Research Project of Nanchong City (18SXHZ0458; NSMC20170210), and Doctoral Research Initiation Foundation of North Sichuan Medical College (CBY15-QD12). Declaration of Interests: The authors declare that they have no conflicts of interest. Ethics Approval Statement: All animal experiments were in compliance with the Guide for the Care and Use of Laboratory Animal (8th Edition, National Institute of Health, 2011) and approved by Animal Care Committee, North Sichuan Medical College First Affiliated Hospital.