Cross-Interactions of BMP and WNT Signaling Pathways Attenuate Androgen Effect on Hair Follicle Stem Cell Differentiation

In 2019, a study was conducted to understand the role of BMPs (Bone Morphogenetic Proteins) on hair follicle stem cell (HFSC) differentiation, and its inhibition by androgens, in the context of androgenetic alopecia (AGA). The study found that the activity of alkaline phosphatase, a marker of hair inductivity, decreased in dermal papilla cells (DPC) treated with DHT (a type of androgen), but was restored by the addition of BMP2. The study also found that BMP2 could overcome the inhibitory effect of DHT on HFSC differentiation. Furthermore, the addition of BMP2 to DPC spheres conditioned media favored ß-catenin translocation in differentiating HFSC, suggesting a cross-talk between BMPs and WNT signaling pathway in HFSC. The study concluded that BMPs are critical factors of the complex epithelial-mesenchymal interaction and their downregulation contribute to AGA development.