Abstract
Background and purpose: Sirtuin1 (SIRT1), the founding member of mammalian class III histone deacetylases, is reported to be a drug target involved in fibrotic diseases. However, whether it is an effective drug target in hypertrophic scar treatment is still not known. Experimental approach: In the present study, we observed that SIRT1 localized to both the epidermis and the dermis of skin tissues by immunohistochemistry. After knock-down of SIRT1 by shRNA or up-regulating SIRT1 by resveratrol, the expression of α-SMA, Col1 and Col3 in fibroblasts were detected by western blots. A mouse excision wound healing model was used to observe the changes in collagen fibre associated with the different expression levels of SIRT1. Key results: SIRT1 expression was inhibited in hypertrophic scar tissue. The down-regulation of SIRT1 resulted in an increased expression of α-SMA, Col1 and Col3 in hypertrophic scar-derived fibroblasts. In contrast, the up-regulation of SIRT1 not only inhibited the expression of α-SMA, Col1 and Col3 in hypertrophic scar-derived fibroblasts but also blocked the activation of TGFβ1-induced normal skin-derived fibroblasts. In the mouse model of wound healing, the deletion of SIRT1 resulted in denser collagen fibres and a more disordered structure, whereas resveratrol treatment led to a more organized and thinner collagen fibre, which was similar to that observed during normal wound healing. Conclusions and implications: The results revealed that SIRT1 negatively regulates TGFβ1-induced fibroblast activation and inhibits excessive scar formation and is, therefore, a promising drug target for hypertrophic scar formation.