Exosomes Derived from Mesenchymal Stem Cells Rescue Myocardial Ischaemia/Reperfusion Injury by Inducing Cardiomyocyte Autophagy Via AMPK and Akt Pathways.
BACKGROUND/AIMS
Reperfusion after an ischaemic insult might cause infarct extension. Mesenchymal stem cell (MSC)-derived exosomes could attenuate myocardial remodelling in animal models of myocardial ischaemia reperfusion injury (MIRI), and the present study aimed to explore the related mechanisms.


METHODS
In vitro, rat H9C2 cardiomyocytes (H9C2s) were exposed to H2O2. Cell viability was detected by the CCK-8 assay, apoptosis was detected by Annexin V-PE/7-AAD staining, ROS production was detected by fluorescence microscopy and flow cytometry, and apoptosis-related proteins and signalling pathway-related proteins were detected by western blot analysis. Autophagic flux was measured using the tandem fluorescent mRFG-GFP-LC3 assay. MSC-derived exosomes were extracted using the total exosome isolation reagent. Apoptosis, myocardial infarction size, heart function and myocardial LC3B expression were examined in an in vivo I/R model by the TUNEL assay, TTC/Evan blue staining, echocardiography and immunohistochemicalstaining, respectively.


RESULTS
In vitro, H2O2 dose-dependently increased ROS production and cell apoptosis in H9C2s and blocked autophagic flux after 3 h of exposure; autophagy gradually decreased thereafter, and the lowest level was detected at 12 h after exposure. MSC-derived exosomes reduced H2O2-induced ROS production and cell apoptosis and enhanced autophagy at 12 h after exposure. In H9C2 cells exposed to H2O2 for 12 h, treatment with exosomes enhanced autophagy via the AMPK/mTOR and Akt/mTOR pathways. Likewise, in vivo exosome injections in rats that underwent I/R injury significantly reduced apoptosis and the myocardial infarct size and upregulated myocardial LC3B expression as well as improved heart function.


CONCLUSIONS
Our results indicate that MSC-derived exosomes could reduce MIRI by inducing cardiomyocyte autophagy via AMPK/mTOR and Akt/mTOR pathways.
['Liu|Liang|L|', 'Jin|Xian|X|', 'Hu|Cui-Fen|CF|', 'Li|Rong|R|', "Zhou|Zhong'e|Z|", 'Shen|Cheng-Xing|CX|']
D055372:AMP-Activated Protein Kinases D000818:Animals D017209:Apoptosis D001343:Autophagy D001854:Bone Marrow Cells D002470:Cell Survival D002478:Cells, Cultured D004195:Disease Models, Animal D055354:Exosomes D006321:Heart D006861:Hydrogen Peroxide D008297:Male D059630:Mesenchymal Stem Cells D015428:Myocardial Reperfusion Injury D032383:Myocytes, Cardiac D051057:Proto-Oncogene Proteins c-akt D051381:Rats D017207:Rats, Sprague-Dawley D017382:Reactive Oxygen Species D015398:Signal Transduction
Exosomes Mesenchymal stem cell Myocardial ischaemia/reperfusion Injury Cardiomyocytes Autophagy