Downregulation of miR-205 in migrating epithelial tongue facilitates skin wound re-epithelialization by derepressing ITGA5

Keratinocyte migration is essential for re-epithelialization during skin wound healing, but the molecular mechanisms regulating this cellular response remain to be completely clarified. Here we show that keratinocyte-specific miR-205 is significantly downregulated in the leading edge of the migrating epithelial tongue after skin injury in mice. In HaCaT keratinocytes, miR-205 could be downregulated by TGF-β1 stimulation. And similar to the effect of TGF-β1, miR-205 knockdown could promote keratinocyte migration in wound scratch model in vitro. Furthermore, topical inhibition of miR-205 by administrating Pluronic gel containing antagomir-205 could accelerate re-epithelialization in mouse skin wound model in vivo. Moreover, we identified integrin alpha 5 (ITGA5) as one key functional miR-205 target in the re-epithelialization process and epidermal downregulation of miR-205 may desilence ITGA5 to promote keratinocyte migration. And knockdown of ITGA5 would abolish the pro-migratory effects of miR-205 inhibition in vitro. What's more, we found dysregulation of miR-205 and its target ITGA5 in epidermis of clinical chronic wound samples with persistence of high level miR-205 and absence of ITGA5. Our findings indicate that downregulation of miR-205 in the leading migrating keratinocytes is critical for re-epithelialization and miR-205 may be a potential therapeutic target for chronic wounds.