MicroRNA-205-5p regulates extracellular matrix production in hyperplastic scars by targeting Smad2

Hypertrophic scar (HS) formation is the result of poor skin-wound healing. At present, the pathogenesis of HS formation is largely unclear. Micro (miR)RNAs have important effects on a variety of biological and pathological processes. The role of miRNA in HS formation remains largely unclear. The present study aimed to investigate the role of miR-205-5p in HS, and explore the underlying molecular mechanism. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to determine the expression of miR-205-5p in HS. Western blot assay and RT-qPCR were performed to assess the expression of associated proteins and genes, respectively. TargetScan was performed to predict the target gene of miR-205-5p, and the luciferase reporter assay was applied to verify the prediction. The function of miR-205-5p on cell proliferation was detected using Cell Counting Kit-8 assay, and cell apoptosis was detected via flow cytometry. miR-205-5p expression was decreased in HS tissues and human hypertrophic scar fibroblasts (hHSFs). Mothers against decapentaplegic homolog (Smad)2 was significantly increased in HS tissues and HSFs, and it was directly targeted by miR-205-5p. Restoration of miR-205-5p suppressed HSF cell proliferation and induced cell apoptosis. It was also demonstrated that RAC-Alpha Serine/Threonine-Protein Kinase (AKT) phosphorylation and the expression of α-smooth muscle actin, collagen I and collagen III were inhibited by miR-205-5p. In addition, Smad2 weakened the effects of miR-205-5p on HSFs. In conclusion, miR-205-5p exhibited an important role in HS by targeting smad2 and suppressing the AKT pathway. These findings provide a clearer understanding of the mechanism for HS that may be used to develop novel treatments for HS.