A role of placental growth factor in hair growth

Background: The dermal papilla (DP) comprises specialized mesenchymal cells at the bottom of the hair follicle and plays a pivotal role in hair formation, anagen induction and the hair cycle. In this study, DPs were isolated from human hair follicles and serially subcultured. From each subculture at passages 1, 3, and 5 (n= 4), we compared gene expression profiles using mRNA sequencing. Among the growth factors that were down-regulated in later passages of human DP cells (hDPCs), placental growth factor (PlGF) was selected. Objective: To elucidate the effect of PlGF on hair growth. Methods: We evaluated the effect of PlGF on hDPCs and on ex vivo hair organ culture. We investigated the effect of PlGF on an in vivo model of depilation-induced hair regeneration. Results: We confirmed that the mRNA and protein expression levels of PlGF significantly decreased following subculture of the cells. It was shown that PlGF enhanced hair shaft elongation in ex vivo hair organ culture. Furthermore, PlGF significantly accelerated hair follicle growth and markedly prolonged anagen hair growth in an in vivo model of depilation-induced hair regeneration. PlGF prevented cell death by increasing the levels of phosphorylated extracellular signal-regulated kinase (ERK) and cyclin D1 and promoted survival by up-regulation of phosphorylated Akt and Bcl2, as determined by Western blotting. Conclusion: Our results suggest that PlGF plays a role in the promotion of hair growth and therefore may serve as an additional therapeutic target for the treatment of alopecia.