Expression level of leucine-rich repeat containing 15 regulates characteristics of dermal papilla cells of human hair follicle

The aggregation of dermal papilla (DP) cells and their interaction with the extracellular matrix (ECM), as well as the expression of basement membrane proteins, are known to be associated with hair development and the hair growth cycle [ [1] Couchman J.R. Gibson W.T. Expression of basement membrane components through morphological changes in the hair growth cycle. Dev. Biol. 1985; 108: 290-298 Crossref PubMed Scopus (40) Google Scholar ]. Androgenetic alopecia (AGA) is a gradual thinning of the thick terminal hair of the frontal balding area, which eventually turns into a thin vellus hair. However, the differences between the frontal and occipital hair follicles, especially in the DPs of AGA patients, are still unclear. Therefore, in this study, we surgically isolated DPs from matched frontal balding and occipital non-balding areas of AGA patients. To mimic the in vivo state of DP cells, DP cells in two-dimensional (2D) cultures were reseeded onto three-dimensional (3D)-culture plates, and differences in gene expression between DP cells from balding areas (B-DPCs) and non-balding areas (NB-DPCs) were determined. One of the most differentially overexpressed genes in 3D-cultured B-DPCs compared with NB-DPCs (Fig. 1a) was the leucine-rich repeat containing 15 (LRRC15). We verified the higher expression of LRRC15 in 3D-cultured B-DPCs compared with NB-DPCs by real-time polymerase chain reaction (PCR) (Fig. S1). Differential expression of LRRC15 between bald DPs and normal DPs in vivo was further demonstrated by immunohistochemical staining (Fig. S2).