ABSTRACT
Necrostatins (Necs) have been developed as a receptor-interacting protein kinase 1 (RIPK1) inhibitor, thus inhibiting necroptosis. In this current study, we have investigated the possible involvement of necroptosis in the hair cycle regulation and further examined its underlying molecular mechanisms. Diverse RIPK1/3 inhibitors and siRNA were tested in the human outer-root sheath (ORS) cells and animal models. The expression and hair cycle-dependent expression of RIPK 1, respectively, were investigated in the hair follicles (HF) of human, pig, and the mouse. Resulting from the experiment, Nec-1s was most effective in the hair growth promotion among several inhibitors. Nec-1s induced the ORS cell proliferation and migration, and increased the HF length in mouse and pig organ cultures. In addition, it accelerated the telogen-to-anagen transition and elongated the anagen period in the mouse model. Both apoptosis and necroptosis were detected in hair cycle. RIPK1 and RIPK3 were highly expressed in ORS cells during the hair regression period. Nec-1s upregulated the mRNA expression of Wnt3a and Wnt5b, and the activity of ß-catenin. Collectively, Nec-1s promotes hair growth through inhibiting necroptosis and activating the Wnt/ß-catenin pathway. Necroptosis is involved in hair cycle regression, and Nec-1s is a promising target for hair-loss treatment.
Subject(s)
Hair Follicle/drug effects , Hair/drug effects , Imidazoles/pharmacology , Indoles/pharmacology , Animals , Apoptosis/drug effects , Cell Line , Cell Movement/drug effects , Cell Proliferation/drug effects , Hair/growth & development , Humans , Male , Mice , Necroptosis/drug effects , Swine , Wnt Signaling Pathway/drug effectsABSTRACT
BACKGROUND: Previous studies demonstrated that adipose-derived stem cells (ASCs) can promote hair growth, but unmet needs exist for enhancing ASC hair inductivity. OBJECTIVE: Therefore, we introduced three trichogenic factors platelet-derived growth factor-A, SOX2, and ß-catenin to ASCs (tfASCs) and evaluated whether tfASCs have similar characteristics as dermal papilla (DP) cells. METHOD: Global gene expression was examined using NGS analysis. Telogen-to-anagen induction, vibrissae hair follicle organ culture and patch assay were used. RESULTS: tfASC cell size is smaller than that of ASCs, and they exhibit short doubling time. tfASCs also resist aging and can be expanded until passage 12. Cell proportion in S and G2/M increases in tfASCs, and tfASCs express high mRNA levels of cell cycle related genes. The mRNA expression of DP markers was notably higher in tfASCs. Moreover, NGS analysis revealed that the global gene expression of tfASCs is similar to that of DP cells. The injection of tfASCs accelerated the telogen-to-anagen transition and conditioned medium of tfASCs increased the anagen phase of vibrissal hair follicles. Finally, we found that the injection of 3D-cultured tfASCs at p 9 generated new hair follicles in nude mice. CONCLUSION: Collectively, these results indicate that 1) tfASCs have similar characteristics as DP cells, 2) tfASCs have enhanced hair-regenerative potential compared with ASCs, and 3) tfASCs even at late passage can make new hair follicles in a hair reconstitution assay. Because DP cells are difficult to isolate/expand and ASCs have low hair inductivity, tfASCs and tfASC-CM are clinically good candidates for hair regeneration.
