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 (PIGF) was selected. Objective: To elucidate the effect of PIGF on hair growth. Methods: We evaluated the effect of PIGF on hDPCs and on ex vivo hair organ culture. We investigated the effect of PIGF on an in vivo model of depilation-induced hair regeneration. Results: We confirmed that the mRNA and protein expression levels of PIGF significantly decreased following subculture of the cells. It was shown that PIGF enhanced hair shaft elongation in ex vivo hair organ culture. Furthermore, PIGF significantly accelerated hair follicle growth and markedly prolonged anagen hair growth in an in vivo model of depilation-induced hair regeneration. PIGF 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 BcI2, as determined by Western blotting. Conclusion: Our results suggest that PIGF plays a role in the promotion of hair growth and therefore may serve as an additional therapeutic target for the treatment of alopecia. (C) 2014 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.