miR-211-5p inhibits the proliferation, migration, invasion, and induces apoptosis of human hypertrophic scar fibroblasts by regulating TGFβR2 expression

Background: Hypertrophic-scar (HS) is the most common pathological healing phenomenon after trauma, especially after deep burns. We aimed to investigate the expression and role of microRNA-211-5p (miR-211-5p) in HS and explore its underlying mechanism. Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of miR-211-5p in 15 cases of HS tissues and normal skin tissues, as well as its expression in human hypertrophic scar fibroblasts (hHSFs) and normal fibroblasts. At the same time, the cell counting kit-8 (CCK-8), scratch test, cell invasion test, and flow cytometry were used to determine cell proliferation, migration, invasion, and apoptosis, respectively. Western blot assay was used to determine the expression of proteins. TargetScan was performed to predict the potential binding sites between miR-211-5p and TGF beta R2, which was then verified by western blotting and luciferase reporter gene experiments. Also, co-transfection of plasmids that overexpress miR-211-5p and TGF beta R2 were used to observe the reversal effect of miR-211-5p. Results: The level of miR-211-5p in HS tissues and hHSFs cells was significantly down-regulated (both P<0.05). The TGF beta R2/Smad3 signaling pathway was activated (both P<0.05). Furthermore, the overexpression of miR-211-5p could inhibit the proliferation (P<0.05), migration (P<0.05), and invasion (P<0.05) of hHSFs cells, and induce their apoptosis (P<0.05), and could also regulate the expression of related proteins ( all P<0.05). Moreover, the overexpression of miR-211- 5p could also inhibit the accumulation of ECM and the activation of the TGF-beta R2/Smad3 pathway (all P<0.05), while the opposite effect (all P<0.05) was observed when the level of miR-211-5p was interfered with. Finally, it was confirmed that miR-211-5p could target TGF beta R2 (all P<0.05), and when hHSFs cells simultaneously overexpressed miR-211-5p and TGF beta R2, the promotion effect of TGF beta R2 on cells was reversed by miR-211-5p (all P<0.05). Conclusions: miR- 211-5p can inhibit the activation of the TGF-beta R2/Smad3 signaling pathway by targeting TGF beta R2, thereby suppressing the proliferation, migration, invasion, and ECM production of hHSFs, and inducing their apoptosis, suggesting that miR-211-5p can become a potential target for the treatment of HS.