Figure 6. Scf from adipocytes is required for the regeneration of HSCs and hematopoiesis and mouse survival after irradiation.

(a–i) One million WBM cells were transplanted into irradiated Adipoq-cre/ER; Scf^GFP/fl mice or Scf^GFP/fl controls 2 weeks after tamoxifen treatment. Non-irradiated Adipoq-cre/ER; Scf^GFP/fl mice and Scf^GFP/fl controls mice were treated with tamoxifen 4 weeks before analysis.

(a–f) White blood cell (a) red blood cell (b), and platelet counts (c), as well as WBM cellularity (d) and numbers of LSK cells (e) and HSCs (f) from Adipoq-cre/ER; Scf^GFP/fl and Scf^GFP/fl mice that were non-irradiated (Con) or analyzed at 2 or 4 weeks after irradiation and bone marrow transplantation. n=5 mice/genotype/condition from 3 independent experiments from two femurs and two tibias per mouse. HSCs could not be detected 2 weeks after irradiation. Two-way ANOVAs with Sidak’s multiple comparisons tests (a–e) or two-tailed Student’s t-tests with Holm-Sidak’s multiple comparisons test (f) were used to assess differences between Adipoq-cre/ER; Scf^GFP/fl and Scf^GFP/fl mice (*P<0.05, **P<0.01).

(g) 3×10⁵ donor WBM cells from the femurs and tibias of non-irradiated mice were transplanted along with equal numbers of recipient WBM cells into irradiated recipient mice. (n=12 recipient mice/genotype from 3 independent experiments). Statistical significance was assessed using two-way repeated measures ANOVAs.

(h) 10⁶ donor WBM cells from the indicated primary recipient mice were transplanted 4 weeks after irradiation along with equal numbers of recipient WBM cells into irradiated secondary recipient mice (n=12 recipient mice/genotype from 3 independent experiments). Statistical significance was assessed using two-way repeated measures ANOVAs with Sidak’s multiple comparisons tests (*P<0.05, **P<0.01, ***P<0.001).

(i) Mouse survival after irradiation and transplantation of 10⁵ WBM cells (n=20 mice/genotype).

(j–l) WBM cellularity (j) and numbers of LSK cells (k) and HSCs (l) from paired Adipoq-cre/ER; Scf^GFP/fl mice and Scf^GFP/fl controls 12 days after 5-FU treatment (*P<0.05; n=7 mice/genotype). Differences between genotypes were assessed using two-tailed Student’s t-tests.

(m) Survival of Adipoq-cre/ER; Scf^GFP/fl mice and Scf^GFP/fl controls after two doses of 5-FU (on days 1 and 8; n=20 mice/genotype). A Gehan-Breslow-Wilcoxon test was used to assess statistical significance in panels i and m. All data in Figure 6 represent mean±SD.