Niche Formed by Bone Morphogenetic Protein Antagonists Gremlin 1 and Gremlin 2 in Human Hair Follicles

The study investigated the role of bone morphogenetic protein (BMP) antagonists, gremlin 1 (GREM1) and gremlin 2 (GREM2), in the formation of niches within human hair follicles, particularly focusing on their expression during different hair cycle phases. Using in situ hybridization on scalp tissue from a 37-year-old female donor, researchers found that GREM2 was robustly expressed in the dermal sheath cup (DSC) during anagen and early catagen phases, suggesting its role in regulating BMP signaling and hair cycling. GREM1 was also expressed in the DSC and epithelial matrix, potentially influencing hair growth directly. The study highlighted the coordinated expression of BMPs and their antagonists in maintaining normal hair cycling, with implications for understanding hair growth and alopecia.