Epigallocatechin-3-Gallate Promotes the Growth of Mink Hair Follicles Through Sonic Hedgehog and Protein Kinase B Signaling Pathways

Abstract

Background: Hair follicles play an essential role in the growth of hair. Epigallocatechin-3-gallate (EGCG), a catechin polyphenol in green tea, has various bioactivities. The present study aims to evaluate the effect of EGCG on the growth of mink hair follicles and investigate the possible molecular mechanisms.Methods: The length of hair follicles was recorded up to 6 days in presence of 0.1–5 μM EGCG. Primary dermal papilla cells (DPCs) and outer root sheath cells (ORSCs) were treated with 0.25–4 μM EGCG, and their growth was evaluated by MTT assay and cell cycle detection. The levels of key molecules in sonic hedgehog (Shh) and protein kinase B (AKT) signaling pathways were further assessed by quantitative real-time PCR, western blot and immunofluorescence. To determine the involvement of Shh and AKT pathways in EGCG-mediated growth-promotion of ORSCs and DPCs, Shh pathway inhibitors cyclopamine and GANT61 or AKT pathway inhibitor LY294002 were employed, and then cell proliferation and cell cycle were analyzed.Results: Data from ex vivo culture showed that, in presence of 0.5–2.5 μM EGCG, the growth of mink hair follicles was promoted. In vitro, the proliferation of DPCs and ORSCs was enhanced by 0.5–4 μM EGCG treatment. More cells entered S phase upon treatment of EGCG, accompanied with upregulation of cyclin D1 and cyclin E1. Furthermore, when exposed to EGCG, the Shh and AKT signaling pathways were activated in both hair follicles and primary DPCs and ORSCs. Inhibiting either of these two pathways partly reversed the effect of EGCG on proliferation and cell cycle of DPCs and ORSCs.Conclusion: EGCG promotes the growth of mink hair follicles at concentrations of 0.5–2.5 μM. This growth-promoting effect of EGCG may be associated with the increased proliferation of DPCs and ORSCs through activating Shh and AKT signaling pathways.

Review of Hair Follicle Dermal Papilla cells asin vitroscreening model for hair growth

“…The research on herbs and active constituents as hair growth promoters has been driven by their less toxicity, easy availability, low‐cost, patient compliance and more than one mode of biochemical action . Specific effects of herbal extracts, polyherbal formulations, flavonoids and natural compounds on DPCs have been examined . In vivo hair growth promoting effects as proof of concept are also mentioned.…”

Ginkgolide B and bilobalide promote the growth and increase β‐catenin expression in hair follicle dermal papilla cells of American minks

“…Four‐month old male American minks ( Neovison vison ) were provided by Field Station of Ministry of Agriculture located in Changbai Mountains and housed in cages at room temperature (20–25 °C) with a constant humidity (55 ± 5%) with food and water available. The hair follicles were separated from skin of minks under a stereoscope following our previously published procedures . Briefly, anagen hair follicles (guard fur and active anagen) were obtained from the back skins 4‐month‐old male American minks (isoflurane anesthetized).…”

“…DP cells were recovered by incubating the cells at 37 °C in DMEM supplemented with 10% fetal bovine serum (FBS) in an atmosphere consisting of 5% CO 2 . Cells from third to fifth passage were used for the subsequent assays …”

“…The hair follicles were separated from skin of minks under a stereoscope following our previously published procedures. [20][21][22] Briefly, anagen hair follicles (guard fur and active anagen) were obtained from the back skins 4-month-old male American minks (isoflurane anesthetized). Small pieces of dorsal skin (~1 cm 2 ) were harvested, and the hair shafts and subcutaneous fat were removed.…”

“…Cells from third to fifth passage were used for the subsequent assays. 20,22 2.3 | Methyl thiazolyl tetrazolium assay DP cells (4 × 10 3 cells) from third to fifth passage were incubated with GKB (0, 25, 50, and 100 μM) or BB (0, 25, 50, and 100 μM) for 0, 12, 24, and 48 hr, respectively Zhang et al, 2018). At each recording point, 100 μL methyl thiazolyl tetrazolium (MTT; M-2128, Sigma) (0.5 mg/mL) was added into cell cultures and incubated at 37 C for 4 hr.…”