The functions of FoxO transcription factors in epithelial wound healing

Re-epithelialisation is a complex process that involves the migration and proliferation of keratinocytes, as well as the production of cytokines and growth factors that affect wound healing. The precise mechanisms that control the tissue repair process remain poorly understood. Recent evidence indicates that FoxO transcription factors play a crucial role in wound healing. In mammals, different isoforms of FoxO, namely, FoxO1, FoxO3, FoxO4 and FoxO6, are present; however, FoxO1 and FoxO3 primarily function in epithelial wound healing. The functions of FoxO proteins in normal wound healing are opposite of those in diabetic wound healing. On the one hand, FoxO transcription factors promote the migration of keratinocytes through up-regulating the expression of transforming growth factor-beta and protecting keratinocytes from oxidative stress. On the other hand, FoxO transcription factors negatively regulate some genes that are needed for re-epithelialisation and keratinocyte migration. This review provides a summary of the functions of FoxO proteins in re-epithelialisation.