Cigarette induced release of exo-miR-34a from 16HBE vesicles targeting CASP2 promoted the proliferation of COPD MRC-5 cell

Objective:To explore how cigarette smoke extract(CES)regulates the expression of exosomal miR-34a in 16 HBE bronchial epithelial cells,thus affecting the proliferation of MRC-5 lung fibroblasts.Methods:CES was prepared from commercially available cigarettes,and 16HBE cells were treated with CES.The exosomal miR-34a collected from Yipeng Ding,Chief Physician,M.D..the supernatant was used for MRC-5 cell culture.The expression level of exosomal miR-34a was detected by RT-PCR.The proliferation ability of MRC-5 cells was determined by CCK-8 cell counting kit.The expression of CASP2 was detected by Western blot,and the target binding of miR-34a and CASP2 gene was verified by dual luciferase.Results:Under the transmission electron microscope,the exosomes in the supernatant of 16 HBE were spherical,with a particle size of about 100 nm;after CES treatment,the expression of exosomal miR-34a significantly increased.Further research showed that the exosomal miR-34a induced by CES can promote the proliferation of MRC-5 cells;miR-34a and CASP2 have a target binding relationship;miR-34a mimic significantly inhibited the expression of CASP2.Conclusion:In CES-induced 16HBE cells,exosomal miR-34a plays a key role in fibroblast proliferation through target binding with the CASP2 gene.