The Effects Of Atrial Fibrillation-derived Exosomes Delivered MiR-107 On Human Vascular Endothelial Cells

Objective: Atrial fibrillation is a common arrhythmia in clinical practice,especially in the elderly,which seriously affects people's health and life.Exosomes are small extracellular vesicles secreted by a variety ofcells,which are double-walled and sealed with lipid.They are secreted by a variety of cells in the body and excreted into body fluids.They can carry the contents of vesicles with functional activity for inter-cell biological signal transmission and play an important role in the physiological and pathological processes of the body.Exosomes are involved in avariety of complex biological effects of the body,such as the regulationof cell differentiation,proliferation,senescence,apoptosis,etc.In the cardiovascular system,exosomes are involved in cardiomyocyte survival,ventricular remodeling,angiogenesis and other processes.Exosome miRNAs play an important role in a variety of cardiovascular diseases.The purpose of this study was to investigate the effects of exosomal miRNA derived from patients with persistent atrial fibrillation on human vascular endothelial cells in vitro.In this study,exosomes were isolated from plasma of patients with persistent atrial fibrillation and healthy people,and the expression levelsof miR-103 a,miR-320 d and miR-107 were detected in exosomes from healthy people and exosomes from patients with persistent atrial fibrillation.To explore the effects of selected exosome miRNAs on human vascular endothelial cells and their related mechanisms will help to reveal a new therapeutic target for atrial fibrillation.Methods: Fastfasting venous blood samples were selected from patients with persistent atrial fibrillation of non-valvular disease who were hospitalized and hospitalized in Department of Cardiology of Shijiazhuang People's Hospital from April to June,2019(n=5)and healthy people during the same period(n=3)for physical examination.First,exosomes were isolated and blood samples from patients with atrial fibrillation and healthy controls were identified.Plasma was extracted by centrifugation,and cells and cell debris were removed by hyper centrifugation.After that,exosome suspension was obtained by PBS washing.Exosome morphology and particle size distribution of exosomes were observed by transmission electron microscopy(TEM,Jeol Ltd,Peabody,MA,USA)and NS300 particle size analyzer(NTA,Malvern Panalytical,Malvern,UK).The specific markers of exosomes(CD81,CD9,and CD63)were detected by Western blot.The expression levels of miR-103a-3p,miR-320 d and miR-107 between normal exosomes and AF-derived exosomes were then compared.Results:We found that miR-107 was significantly upregulated in AF-derived exosomes and was selected for subsequent experiments.Dual luciferase reporter assay showed that USP14 was a downstream target of miR-107.PKH67 staining showed that exosomes could be absorbed by HUVECs after 24 h and 48 h of co-culture.Subsequently,HUVECs were transfected with miR-107 mimics and treated with AF-derived exosomes.It can be seen that the overexpression of exosome miR-107 inhibited HUVECs cell viability and migration,promoted cell apoptosis,increased G0/G1 phase cells,and decreased S phase cells.Finally,RT-q PCR results showed that the overexpression of miR-107 in exosomes down-regulated the expressions of Bcl2,while up-regulated theexpressions of ERK2,FAK,and Bax.Conclusion: The expression of exosomes miR-107 in AF-derived was up-regulated,and exosomes miR-107 may regulate cell viability,migration,apoptosis,and cycle by mediating the miR-107/USP14 pathway.The overexpression of exosome miR-107 may affect the growth of HUVECs by regulating the expression of ERK2,FAK,Bcl2 and Bax.These findings will provide new insights into miR-107 as a potential target for the treatment of AF and the miR-107/USP14 pathway as a potential therapeutic approach for AF.