Plasma exosomes induced by remote ischaemic preconditioning attenuate myocardial ischaemia/reperfusion injury by transferring miR-24

Wen Minghua,Gong Zhijian,Wang Luqiao,Yu Lingling,Wang Zhenzhen,Wang Xiaozhong,Lu Peng,Liang Qiang,Xu Minxuan,Cheng Xiaoshu,Zhan Biming,Huang Chahua,Xu Jianqing,Zhang Weifang,Bao Huihui

doi:10.1038/s41419-018-0274-x

Abstract

Remote ischaemic preconditioning (RIPC) is well known to protect the myocardium against ischaemia/reperfusion injury (IRI). Exosomes are small extracellular vesicles that have become the key mediators of intercellular communication. Various studies have confirmed that circulating exosomes mediate RIPC. However, the underlying mechanisms for RIPC-induced exosome-mediated cardioprotection remain elusive. In our study, we found that the expression level of miR-24 was higher in exosomes derived from the plasma of rats subjected to RIPC than in exosomes derived from the plasma of control rats in vivo. The rat plasma exosomes could be taken up by H9c2 cells. In addition, miR-24 was present in RIPC-induced exosomes and played a role in reducing oxidative stress-mediated injury and decreasing apoptosis by downregulating Bim expression in H2O2-treated H9c2 cells in vitro. In vivo, miR-24 in RIPC-induced exosomes reduced cardiomyocyte apoptosis, attenuated the infarct size and improved heart function. Furthermore, the apoptosis-reducing effect of miR-24 was counteracted by miR-24 antagomirs or inhibitors both in vitro and in vivo. Therefore, we provided evidence that RIPC-induced exosomes could reduce apoptosis by transferring miR-24 in a paracrine manner and that miR-24 in the exosomes plays a central role in mediating the protective effects of RIPC.

Highlights

Ischaemic heart disease and the resulting heart failure remain the leading causes of death and disability in worldwide
The exosomes induced by remote ischaemic preconditioning (RIPC) were obtained from the plasma using Exoquick followed by fibrin clear to prevent its co-precipitation, and their morphology and phenotypes were determined based on exosome characterisation as previously described[23]
The expression of exosomal markers, including CD63, CD9 and CD81 was detected in RIPC-EXO by western blotting, and the levels of these markers were higher in RIPC-EXO than in EXO (Fig. 1f, g)

Summary

Introduction

Ischaemic heart disease and the resulting heart failure remain the leading causes of death and disability in worldwide. Novel therapies are required to protect the heart against the detrimental effects of acute ischaemia/ reperfusion injury (IRI)[1]. It is well known that remote ischaemic preconditioning (RIPC) protects the myocardium against IRI, but the underlying mechanism remains elusive. Exosomes are EVs, which are smaller than 150 nm in diameter. Exosomes are enriched in components, including RNA, microRNAs (miRNAs), proteins and lipids. EVs can be targeted to the recipient cells via their surface molecules. Once attached to the target cell, EVs can induce signalling via receptor–ligand interactions, and be internalised by phagocytosis and/or endocytosis or even fuse with the membrane of the target cell to deliver cargo into the cytoplasm, modifying the target cell’s

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