Figure 4.

Wounding enhances SG renewal by recruiting progenies of bulge stem cells

(A) Experimental timeline for fate mapping experiments using Lgr5:mTmG and K15:mTmG mice after wounding the back skin of 8-week-old mice.

(B and C) Tracing of K15⁺ SCs in K15:mTmG mice 20 days post-wounding. Note that the vast majority of sebocytes in the HF adjacent to the wound and some interfollicular epidermal cells were labeled (B), and mGFP⁺ cells within the SGs were counted (B and C, Data are represented as mean ± SEM, ∗∗∗p < 0.005, t-test, n = 3).

(D and E) Tracing of Lgr5⁺ SCs in Lgr5:mTmG mice at 15 and 20 days post-wounding. The vast majority of SG cells adjacent to wounds were labeled (D), and mGFP⁺ cells within the SGs were counted (D and E), Data are represented as mean ± SEM, ∗∗∗p < 0.005, t-test, n = 3).

(F) A schematic summary shows that wounding to the skin accelerated the differentiation of bulge and lower bulge SCs into SG cells.

(G and H) Tracing of Gli1⁺ SCs in Gli1:mTmG mice at 15 and 20 days post-wounding (G), and mGFP⁺ cells within the SGs were counted (H, Data are represented as mean ± SEM, ∗∗∗p < 0.005, t-test, n = 3 mice).

(I) A schematic summary showing the contribution of upper bulge SCs to SG cells after wounding to the skin. PWD, post-wound day; Derm: dermis; Epi, epidermis; New-Epi, new-epidermis; IFE, interfollicular epidermis; IFN, infundibulum; SG, sebaceous glands; W: wound. Scale bars: 50 μm.