Thymosin Beta-4 Induces Mouse Hair Growth

The study explored the effects of VEGF165 and VEGFR-2 on human outer root sheath cells from the central hair follicle epithelium, revealing that VEGFR-2 was present in these cells both in vivo and in vitro. VEGF165 was found to enhance cell proliferation and migration, reduce homotypic adhesion, and increase heterotypic adhesion. It also upregulated integrin β1 and downregulated lgr6 expression, while promoting phosphorylation of VEGFR-2, Erk1/2, c-Jun, and p38. These effects were reversed by a VEGFR-2 neutralizing antibody, indicating that VEGF/VEGFR-2 had a significant role in hair follicle regulation beyond its known function in angiogenesis.

The study demonstrated that Vascular Endothelial Growth Factor (VEGF) induced the proliferation of human hair follicle dermal papilla (DP) cells through the VEGF receptor 2 (VEGFR-2)-mediated activation of the ERK signaling pathway. The expression of VEGFR-2 on DP cells was confirmed using RT-PCR and Western blot analysis, and its localization was identified by immunofluorescence. Exogenous VEGF165 was shown to stimulate DP cell proliferation in a dose-dependent manner, an effect that was inhibited by a VEGFR-2 neutralizing antibody and an ERK inhibitor. The study concluded that VEGFR-2 is expressed on primary human hair follicle DP cells, and VEGF promotes their proliferation via the VEGFR-2/ERK pathway, without affecting the p38, JNK, or AKT signaling pathways.