microRNA-181a promotes the proliferation of hypertrophic scar fibroblasts and inhibits their apoptosis via targeting phosphatase and tensin homolog.

BACKGROUND

This study aimed to compare the expression of microRNA (miR)-181a and phosphatase and tensin homolog (PTEN) in hypertrophic scar tissue and cells and to explore the effects of miR-181a and PTEN on the proliferation and apoptosis of the human scar fibroblast cell line HSFb.

METHODS

HSFb cells were transfected with miR-negative control (miR-NC), miR-181a mimics, miR-181a inhibitor, pcDNA3.1-PTEN (pc-PTEN), or small interfence-PTEN (si-PTEN) plasmid using a Lipofectamine 2000 transfection kit. The effects of miR-181a and PTEN on the proliferation and apoptosis of HSFb were determined using a Cell Counting Kit (CCK)-8 experiment and flow cytometry, respectively. The effects of miR-181a and PTEN on the expression of apoptosis-related proteins in HSFb, including type I collagen (Col-1) and type III collagen (Col-3), were measured by western blot. Finally, the relationship between miR-181a and PTEN was explored by the dual-luciferase reporter gene experiment.

RESULTS

The miR-181a in hypertrophic scar tissues and HSFb were significantly up-regulated compared to embryo skin fibroblast (ESF-1) cells and normal tissues (P<0.05), whereas the opposite results were seen for PTEN expression (P<0.05). Inhibiting miR-181a or upregulating the expression of PTEN significantly suppressed the proliferation of HSFb (P<0.05) and induced their apoptosis (P<0.05). Western blot revealed that inhibiting and upregulating miR-181a and PTEN, respectively, decreased the expression of the B-cell lymphoma-2 (Bcl-2), Col-1, and Col-3 proteins in HSFb, but significantly up-regulated the expression of Bcl-2-associated X protein (Bax), cleaved caspase-3 (c-caspase-3), and cleaved caspase-9 (c-caspase-9) (P<0.05). The dual-luciferase reporter gene experiment results confirmed PTEN to be the downstream target gene of miR-181a. Simultaneous upregulation of miR-181a and PTEN expression had no significant effect on the proliferation and apoptosis of HSFb.

CONCLUSIONS

miR-181a promotes the up-regulation of Col-1 and Col-3, and regulates the proliferation and apoptosis of HSFb by targeting PTEN, thereby enhancing the formation of hypertrophic scarring (HS). Therefore, miR-181a and PTEN may be potential therapeutic targets for the treatment of HS.