Small Molecules Facilitate Single Factor-Mediated Sweat Gland Cell Reprogramming
Abstract Background: Large skin defect caused severe disruption to the overall skin structure and irreversible damage of sweat gland (SG), resulting in destroy of physiological function of the skin. Reprogramming fibroblasts into sweat gland lineages may provide a promising strategy to obtain the desirable cell types for functional repair and regeneration of damaged skin. Methods: A direct reprogramming strategy of single factor ectodermal dysplasia antigen (EDA) in combination with small molecule cocktails promoting cell-fate conversion to regenerate SG cells from human dermal fibroblasts (HDFs) was developed. Quantitative PCR (qPCR), flow cytometry, calcium activity analysis, immunocytochemical analyses and starch-iodine sweat tests were used to characterize the phenotype, gene expression and function features of the induced sweat gland cells (iSGCs). Results: EDA overexpression drove HDFs toward SG lineages, and HDFs transfected with EDA acquired sweat gland cell phenotype in sweat gland conditional medium (SGM). Small-molecule cocktails favoring SG lineages greatly accelerated the SG fate program in SGM-treated HDF-EDA cells and further induced the regeneration of iSGCs. The HDFs-derived iSGCs exhibited similar phenotypical and functional features of native sweat gland cells. Eventually, in vivo transplantation experiment confirmed that iSGCs had the ability to regenerate SG structurally and functionally.Conclusion: We developed a SG reprogramming strategy to generate functional iSGCs from HDFs by using single factor EDA in combination with small molecules. The generation of iSGCs has important implications for in situ skin regeneration with restoration of sweat glands in the future.