Influence of human adipose-derived stromal cells on Wnt signaling in organotypic skin culture

BACKGROUND:: Human adipose-derived stromal cells (hASCs) produce various cytokines. Also, there is a growing opinion that a large proportion of the useful effects of cell therapy may be attributable to the secretion of cytokines. Several reports suggested beneficial effects of hASCs on skin. These include antioxidant activity, accelerated wound healing, whitening effects, and antiaging. We investigated the effect of hASCs on skin Wnt signaling, which is associated with skin regeneration and differentiation. METHODS:: Pieces of human skin were cocultured with hASCs, and 2 chambered transwell culture plates were used to prevent direct contact between hASCs and skin. In the control group, pieces of skin were cultured without hASCs. Wnt1, Axin2, TCF1, LEF1, and DKK1 mRNA expressions were quantitatively assessed using real-time polymerase chain reaction. The expression levels of β-catenin were compared using Western blot and immunohistochemical analyses. RESULTS:: The Wnt1 and LEF1 mRNA expression of cultured skin was positively influenced by the presence of hASCs in culture medium (P < 0.05). The total β-catenin protein level in hASC-cocultured skin was higher than that of the control group. Immunohistochemical staining showed that the β-catenin-stained area of dermis was larger in the hASC-cocultured group than in the control group, and most of the positively stained cells in the dermis were fibroblasts. CONCLUSIONS:: The results of the current study showed that hASCs promoted canonical Wnt signaling in organotypic skin culture through paracrine effects, and the increased Wnt signaling was mainly due to dermal fibroblasts.