Overexpression of miR-101 suppresses collagen synthesis by targeting EZH2 in hypertrophic scar fibroblasts

Background:MicroRNA-101(miR-101)is a tumor suppressor microRNA(miRNA)and its loss is associated with the occurrence and progression of various diseases.However,the biological function and target of miR-101 in the pathogenesis of hypertrophic scars(HS)remains unknown.Methods:We harvested HS and paired normal skin(NS)tissue samples from patients and cultured their fibroblasts(HSF and NSF,respectively).We used quantitative reverse transcriptase polymerase chain reaction(qRT-PCR),fluorescence in situ hybridization(FISH),enzyme-linked immunosorbent assays(ELISA)and Western blot analyses to measure mRNA levels and protein expression of miR-101,enhancer of zeste homolog 2(EZH2),collagen 1 and 3(Col1 and Col3)andα-smooth muscle actin(α-SMA)in different in vitro conditions.We also used RNA sequencing to evaluate the relevant signaling pathways and bioinformatics analysis and dual-luciferase reporter assays to predict miR-101 targets.We utilized a bleomycin-induced fibrosis mouse model in which we injected miR-101 mimics to evaluate collagen deposition in vivo.Results:We found low expression of miR-101 in HS and HSF compared to NS and NSF.Overexpressing miR-101 decreased Col1,Col3 andα-SMA expression in HSF.We detected high expression of EZH2 in HS and HSF.Knockdown of EZH2 decreased Col1,Col3 andα-SMA in HSF.Mechanistically,miR-101 targeted the 3-untranslated region(3UTR)of EZH2,as indicated by the decreased expression of EZH2.Overexpressing EZH2 rescued miR-101-induced collagen repression.MiR-101 mimics effectively suppressed collagen deposition in the bleomycin-induced fibrosis mouse model.Conclusions:Our data reveal that miR-101 targets EZH2 in HS collagen production,providing new insight into the pathological mechanisms underlying HS formation.