MicroRNA-149 contributes to scarless wound healing by attenuating inflammatory response

A fibrotic or pathological scar is an undesired consequence of skin wound healing and may trigger a series of problems. An attenuated inflammatory response is a significant characteristic of fetal skin wound healing, which can contribute to the scarless healing of fetal skin. According to deep sequencing data, microRNA-149 (miR-149) expression was increased in mid-gestational compared with that in late-gestational fetal skin keratinocytes. It was demonstrated that overexpression of miR-149 in HaCaT cells can downregulate the expression of pro-inflammatory cytokines interleukin (IL) -1 alpha, IL-1 beta, and IL-6 at basal levels and in inflammatory conditions. Furthermore, miR-149 was revealed to indirectly accelerate transforming growth factor-beta 3 and collagen type III expression in fibroblasts, which are essential cells in extracellular matrix remodeling. In a rat skin wound model, miR-149 improved the quality of the arrangement of collagen bundles and reduced inflammatory cell infiltration during skin wound healing. These results indicate that miR-149 may be a potential regulator in improving the quality of skin wound healing.