β-Catenin Stabilization in Skin Fibroblasts Causes Fibrotic Lesions by Preventing Adipocyte Differentiation of the Reticular Dermis

The Wnt/beta-catenin pathway plays a central role in epidermal homeostasis and regeneration, but how it affects fibroblast fate decisions is unknown. We investigated the effect of targeted beta-catenin stabilization in dermal fibroblasts. Comparative gene expression profiling of stem cell antigen 1(-) (Sca1(-)) and Sca1(+) neonatal fibroblasts from upper and lower dermis, respectively, confirmed that Sca1(+) cells had a preadipocyte signature and showed differential expression of Wnt/beta-catenin associated genes. By targeting all fibroblasts or selectively targeting Dlk1(+) lower dermal fibroblasts, we found that beta-catenin stabilization between developmental stages E16.5 and P2 resulted in a reduction in the dermal adipocyte layer with a corresponding increase in dermal fibrosis and an altered hair cycle. The fibrotic phenotype correlated with a reduction in the potential of Sca1(+) fibroblasts to undergo adipogenic differentiation ex vivo. Our findings indicate that Wnt/beta-catenin signaling controls adipogenic cell fate within the lower dermis, which potentially contributes to the pathogenesis of fibrotic skin diseases.