Development and validation of a comprehensive in vitro organ model for androgenetic alopecia

Male androgenetic alopecia (AGA) is the most common hair loss disorder. However, research on AGA remains limited, primarily due to the lack of clinical samples and imperfect AGA models incapable of replicating the androgen sensitivity of AGA.

An AGA organ model was established by optimizing the concentration of dihydrotestosterone (DHT) and simulating AGA pathology through organotypic culture. The model's effectiveness was evaluated using histology, immunohistochemistry, and RNA-seq analysis, focusing on hair follicle (HF) growth, proliferation, apoptosis, key signaling molecules in AGA, stem cell state, and androgen receptor (AR) alterations.

We determined the optimal DHT concentration for our AGA organ model at 5 × 10^- 6 mol/L. The model demonstrated inhibited HF growth and accelerated entry into the catagen phase, with a 24% reduction in matrix cell proliferation and a 31% increase in apoptosis. Key molecular changes included decreased β-catenin and IGF-1 expression and elevated TGF-β1, DKK1, p21, and AR levels. The expression of the dermal papilla (DP) cell marker versican was reduced, while the follicular stem cell marker K15 remained unchanged. Moreover, the model successfully replicated the partial reversal of DHT's effects by minoxidil or AR antagonist bicalutamide. RNA-seq analysis revealed alterations in the Wnt/β-catenin and TGF-β signaling pathways and inflammatory responses in the AGA model.

Our study presents a novel human in vitro AGA model that closely mirrors the clinical features of AGA in terms of morphology and molecular pathology. Beyond mechanistic research, this model provides a translationally relevant platform for drug evaluation and personalized therapeutic development. By preserving native androgen sensitivity and pathological microenvironment, this work lays a foundation for discovering new regenerative treatments for AGA.