Extended Data Fig. 5: Kitl deficiency in the niche for McSCs causes McSC depletion and resultant hair graying.
From: Antagonistic stem cell fates under stress govern decisions between hair greying and melanoma
a, FACS sorting analysis of HFSCs/Hg in K15-EGFP Tg murine skin. The singlets/7AAD−/GFPhigh/ITGA6high/ScaI− population was used as niche cells for McSCs. b, Immunohistological analysis of KITL in the bulge (KRT15+) and hair germ (P-CAD+) of Kitl-GFP KI mice at telogen. Scale Bar = 30 μm. Bg=Bulge, Hg=Hair germ. c, Immunohistological analysis of KITL in the dorsal skin of Kitl-GFP KI mice at 3 days after treatment with Vehicle or DMBA. Arrows indicate GFP+ cells in Bg/sBg (Bulge/sub-Bulge) and arrowheads indicate GFP+ cells in the IFE. Scale Bar = 200 μm. d, Experimental scheme for Kitl cKO mice. Dp; Hair depilation. e,f,g, Coat colors of WT and K15CrePR; Kitlfx/fx (Kitl cKO) mice at 3 weeks (e), at 7 weeks (f) and at 28 days in the 1st hair cycle (1st-D28) (g). h, Immunohistological analysis of McSCs in the bulge of WT and Kitl cKO mice at 5 days in the 2nd hair cycle (2nd-D5). McSCs are visualized with Dct-LacZ Tg mice. Graph showing quantification of McSCs in the bulge (WT; n=3, Kitl cKO; n=4, biological independent experiments). Scale Bar = 30 μm. Two-tailed Student’s t-test. i, Coat colors of WT and K14-Kitl Tg mice after irradiation with 0 Gy or 5 Gy IR. Immunohistological analysis of McSCs in the bulge of WT and K14-Kitl Tg mice. McSCs are visualized using Dct-LacZ Tg mice. Scale Bar = 50 μm. Graph showing the frequency of hair follicles still containing McSCs in the bulge (n=3, biological independent experiments). Two-tailed Student’s t-test. j, Coat colors of Tyr-Cre; I-PpoI (I-PpoI) and K14-Kitl; Tyr-Cre; I-PpoI (K14-Kitl/I-PpoI) mice and immunohistological analysis of KIT+ cells in the bulge. The dotted lines show the Bg/sBg. Scale Bar = 30 μm. k, Experimental scheme for microarray analysis with FACS-purified McSCs. McSCs are labeled using the Dct-H2B-GFP KI allele. l, GSEA Enrichment plot for KEGG Arachidonic acid metabolism, RIG-I like receptor signaling pathway and Cytosolic DNA sensing pathway. m, Quantification of the relative mRNA expression level of COX2 in vitro using NHEMs (n=3, biological independent experiments). One-way ANOVA with Dunnett’s post-hoc tests. Rpl11 is used as an internal control for the qPCR analysis. Data are presented as means ± SEM (h,i,m).
