Exosomes derived from human umbilical cord mesenchymal stem cells protect against papain-induced emphysema by preventing apoptosis through activating VEGF-VEGFR2-mediated AKT and MEK/ERK pathways in rats

INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is a leading cause of high mortality and heavy burden in the world. Unfortunately, emphysema, as an important component of COPD, has no curative treatments currently. Recently, human umbilical cord mesenchymal stem cells-derived exosomes (hUCMSC-Ex) constitute a promising alternative approach for tissue regeneration and repair. However, the roles of hUCMSC-Ex in emphysema and its mechanism are largely unknown. Here, we investigated the effect and the action mechanism of hUCMSC-Ex in repairing emphysema induced by papain in rats. METHODS: SD rats were used to establish a papain-induced emphysema model and estimate the effect and mechanism of hUCMSC-Ex treatment. H&E staining and mean linear intercept (MLI) were used to evaluate the hUCMSC-Ex effect on emphysema. Western blotting, TUNEL and miRNA-seq were used to investigate the molecular mechanisms of hUCMSC-Ex treatment in models of papain-induced emphysema. RESULTS: Papain treatment led to typical emphysema, while hUCMSC-Ex reversed emphysematous changes effectively. Apoptosis of endothelial cells and other types of cells were observed in models, while hUCMSC-Ex effectively prevented their apoptosis. hUCMSC-Ex repressed active caspase-3, activated VEGF-VEGFR2-mediated AKT pathway and MEK/ERK pathway in emphysematous lungs. Notably, several miRNAs, such as hsa-miR-10a-5p and hsa-miR-146a-5p, were target related to the roles of hUCMSC-Ex in papain-induced emphysema through VEGF-VEGFR2-mediated AKT and MEK/ERK pathways. CONCLUSIONS: hUCMSC-Ex effectively rescued the papain-induced emphysema injury through VEGF-VEGFR2-mediated AKT pathway and MEK/ERK pathway.