Escin Activates Canonical Wnt/ß-Catenin Signaling Pathway by Facilitating the Proteasomal Degradation of Glycogen Synthase Kinase-3ß in Cultured Human Dermal Papilla Cells.

Abnormal inactivation of the Wnt/ß-catenin signaling pathway is involved in skin diseases like androgenetic alopecia, vitiligo and canities, but small-molecule activators are rarely described. In this study, we investigated the stimulatory effects of escin on the canonical Wnt/ß-catenin signaling pathway in cultured human dermal papilla cells (hDPCs). Escin stimulated Wnt/ß-catenin signaling, resulting in increased ß-catenin and lymphoid enhancer-binding factor 1 (LEF1), the accumulation of nuclear ß-catenin and the enhanced expression of Wnt target genes in cultured hDPCs. Escin drastically reduced the protein level of glycogen synthase kinase (GSK)-3ß, a key regulator of the Wnt/ß-catenin signaling pathway, while the presence of the proteasome inhibitor MG-132 fully restored the GSK-3ß protein level. The treatment of secreted frizzled-related proteins (sFRPs) 1 and 2 attenuated the activity of escin in Wnt reporter assays. Our data demonstrate that escin is a natural agonist of the canonical Wnt/ß-catenin signaling pathway and downregulates GSK-3ß protein expression by facilitating the proteasomal degradation of GSK-3ß in cultured hDPCs. Our data suggest that escin likely stimulates Wnt signaling through direct interactions with frizzled receptors. This study underscores the therapeutic potential of escin for Wnt-related diseases such as androgenetic alopecia, vitiligo and canities.