Abstract: Objective To investigate the effect of hsa-Let-7a-5p on the fibrosis process of localized scleroderma fibroblasts (LSFs) and its correlation with transforming growth factor-β receptor (TGF-βR) and TGF-β/Smad signaling pathway. Methods LSFs were infected with lentiviral vectors carrying hsa-Let-7a-5p and shTGF-βR1 and blank lentiviral vectors. The proliferation and migration of LSFs in each group were detected by CCK-8 method and scratch test. Real-time quantitative PCR (RT-qPCR), immunofluorescence and Western blot were used to detect the transfection efficiency, and the mRNA and protein levels of collagen type Ⅰ & Ⅲ, α-SMA, TGF-βR1, TGF-β, p-Smad2/3 in LSFs in each group. Results After virus infection of LSFs, the expression of TGF-βR1 in the shTGF-βR1 group was significantly lower than that in the control groups (P＜0.05); the cell proliferation rate and migration of shTGF-βR1 group were inhibited(P＜0.05); The mRNA and protein expression of collagen type Ⅰ & Ⅲ, α-SMA, TGF-β, p-Smad2/3 were significantly lower than those of the control groups(P＜0.05). Bioinformatics analysis showed that hsa-Let-7a-5p can be matched with the target region of TGF-βR1 3′-UTR, and the expression of hsa-Let-7a-5p in the lentivirus transfection group was significantly increased compared with the control groups(P＜0.05), the expression of TGF-βR1 was significantly decreased(P＜0.05). The cell proliferation rate and migration ability of the hsa-Let-7a-5p group were decreased; the mRNA and protein expression of collagen type Ⅰ & Ⅲ, α-SMA, TGF-β, p-Smad2/3 in the hsa-Let-7a-5p group were significantly lower than those of the control groups(P＜0.05). Conclusions hsa-Let-7a-5p regulates TGF-β/Smad pathway by targeting at TGF-βR1,inhibits proliferation and migration of LSFs, decreases fibrotic markers in LSFs thereby inhibiting fibrosis in localized scleroderma.

Key words: hsa-Let-7a-5p, localized scleroderma, fibrosis