Expression of Retinoid Nuclear Receptor Superfamily Members in Human Hair Follicles and Its Implication in Hair Growth

The study investigated the expression of retinoid nuclear receptor superfamily members in human hair follicles and their impact on hair growth. It was found that retinoic acid binding protein-II and retinoid-X-receptor-alpha were consistently expressed in both dermal and epithelial compartments, similar to the vitamin D receptor. In dermal papilla cells, RAR beta was always expressed, while RAR alpha and RAR gamma were not. In dermal sheath fibroblasts, all three RAR mRNAs were moderately expressed, but in the epithelial compartment, RAR beta was absent. The study also revealed that RAR agonists, such as all-trans RA and CD367, inhibited hair follicle survival in vitro, whereas the RXR agonist CD2425 stimulated hair growth and survival, akin to 1 alpha,25-dihydroxyvitamin D3, indicating that RXR agonists could potentially promote hair growth in humans.