Transforming growth factor-β (TGF-β) signaling in healthy human fetal skin: A descriptive study

BackgroundTGF-β plays an important role in growth and development but is also involved in scarring and fibrosis. Differences for this growth factor are known between scarless fetal wound healing and adult wound healing. Nonetheless, most of the data in this area are from animal studies or in vitro studies and, thus, information about the human situation is incomplete and scarce.ObjectiveThe aim of this study was to compare the canonical TGF-β signaling in unwounded human fetal and adult skin.MethodsQ-PCR, immunohistochemistry, Western Blot and Luminex assays were used to determine gene expression, protein levels and protein localization of components of this pathway in healthy skin.ResultsAll components of the canonical TGF-β pathway were present in unwounded fetal skin. Compared to adult skin, fetal skin had differential concentrations of the TGF-β isoforms, had high levels of phosphorylated receptor-Smads, especially in the epidermis, and had low expression of several fibrosis-associated target genes. Further, the results indicated that the processes of receptor endocytosis might also differ between fetal and adult skin.ConclusionThis descriptive study showed that there are differences in gene expression, protein concentrations and protein localization for most components of the canonical TGF-β pathway between fetal and adult skin. The findings of this study can be a starting point for further research into the role of TGF-β signaling in scarless healing.