Bacillus/Trapa japonica Fruit Extract Ferment Filtrate enhances human hair follicle dermal papilla cell proliferation via the Akt/ERK/GSK-3β signaling pathway.

Background: Despite advances in medical treatments, the proportion of the population suffering from alopecia is increasing, creating a need for new treatments to control hair loss and prevent balding. Treatments based on plant-derived compounds could potentially prevent hair loss. Human hair follicle dermal papilla (HDP) cells, a type of specialized fibroblast in the hair bulb, play an essential role in controlling hair growth and in conditions such as androgenic alopecia. We examined the effect of Bacillus/Trapa japonica fruit ferment filtrate extracts (TJFs) on HDP cells to determine whether activation of the Akt/ERK/GSK-3β signaling pathway improved HDP cell proliferation.

Methods: We prepared TJFs using various methods. The extract properties were analyzed using WST-1, Lowry, and cell migration assays as well as immunofluorescence staining. We also determined the cell cycle stage and performed western blotting and an in ovo chick chorioallantoic membrane assay. Last, we constructed an organotypic three-dimensional cell culture model for immunohistochemical use.

Results: Our study confirmed that the TJFs contained numerous peptides and five unknown fractions. The TJFs stimulated HDP cell proliferation and migration via the Akt/ERK/GSK-3β signaling pathway. To verify that the Akt/ERK/GSK-3β pathway affected HDP cell proliferation, we treated HDP cells with LY294002 (an Akt inhibitor), BIO (a GSK-3β inhibitor), and PD98059 (an ERK inhibitor). The TJFs also induced cell cycle progression, inhibited type І 5α-reductase, decreased apoptosis, and enhanced angiogenesis (vascular expansion). In addition to these signaling pathways, proteins including insulin-like growth factor-1 and keratinocyte growth factor, stimulating hair growth, were detected in the three-dimensional cell culture model.

Conclusions: Our results confirmed that TJFs enhance HDP cell proliferation via the Akt/ERK/GSK-3β signaling pathway, suggesting a potential treatment for alopecia.