![Figure 6. Accelerated return of HSCs to quiescence in SPARC-deficient mice is independent of TGF-β signaling. (A) CD81 expression is identical between HSCs in WT and Sparc−/− mice and shows the same changes in response to 5-FU (N = 4 per group and time point; mean and SD). (B) Levels of active TGF-β are comparable in WT and SPARC-deficient mice at homeostasis and at different time points after 5-FU treatment (N = 6 per group and time point; mean and SD). (C) Ki67/Hoechst cell cycle analysis of WT and Sparc−/− mice 11 days after 5-FU. Additionally, mice received either the TGF-β blocking antibody 2G7 or isotype control IgG1 at days 8 and 10 after 5-FU injection. TGF-β pathway inhibition delays HSC quiescence induction in WT but not Sparc−/− mice (N = 6 per group and time point; mean and SD; *P < .05; ***P < .005; ****P < .001; unpaired 2-tailed Student t test). (D) p27 mRNA expression in HSCs (Lin−Sca-1+CD48−CD150+CD34−) before and 9 or 10 days after 5-FU. (E) Survival curve of Sparcflox2 and MxCre;Sparcflox2 mice treated with 5-FU at a dose of 150 μg/g at 10-day intervals starting 5 weeks after deletion (N = 8-9 per group; median survival: Sparcflox2 = 45 days, MxCre;Sparcflox2 = 50 days; no significant difference; log-rank [Mantel-Cox] test and Gehan-Breslow-Wilcoxon test). Time points of 5-FU injections are indicated with arrows. (F) Niche cell frequencies of WT and Sparc−/− mice 10 days after 5-FU and at baseline. Niche cells were isolated from bone chips and identified with the indicated markers by flow cytometry (N = 4 per group and time point; mean and SD). (G) SPARC mRNA expression in niche cells of WT mice before and 5 or 10 days after 5-FU (N = 6 per group and time point; mean and SD; *P < .05; **P < .01; ***P < .005; 1-way ANOVA followed by Dunnett’s multiple comparison test). (H) SPARC mRNA expression in hematopoietic progenitors of WT mice before and 5 or 10 days after 5-FU (N = 6 per group and time point; mean and SD; *P < .05; **P < .01; 1-way ANOVA followed by Dunnett’s multiple comparison test).](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/123/26/10.1182_blood-2013-10-533711/4/4054f6.jpeg?Expires=1725135813&Signature=qb45GCfUjz4d7XWpBBhctuRsFD3Bx8~2G~GWFWoHcNPVxMJZrCUzXmbTe06bCN3v4Li1xL6L8gmcEBr6ZfUaq~eviFOqXcr3SnYrQGh2S2r2hXoz9PUuUDp~eWMMjAl1wDojZV9V16dtu1YfINzvRClrg~uspfl7Psj~cMt6EDRhBXXoAEHRBucM-Bj-LTDmXw6QHwUqgOb5n1sKbppsOczn1Wn6t1ZoqHk6esQ7NHNSUcYXiGCCKpIrgMVSRp1nv9pofIErRwzvO7yKj1yeIy0poXa1fl2c5qoGgYycjo1UPmbFWGQtexsZvW5HbSabLY9HdM~JCab-2cNILDSaow__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Accelerated return of HSCs to quiescence in SPARC-deficient mice is independent of TGF-β signaling. (A) CD81 expression is identical between HSCs in WT and Sparc−/− mice and shows the same changes in response to 5-FU (N = 4 per group and time point; mean and SD). (B) Levels of active TGF-β are comparable in WT and SPARC-deficient mice at homeostasis and at different time points after 5-FU treatment (N = 6 per group and time point; mean and SD). (C) Ki67/Hoechst cell cycle analysis of WT and Sparc−/− mice 11 days after 5-FU. Additionally, mice received either the TGF-β blocking antibody 2G7 or isotype control IgG1 at days 8 and 10 after 5-FU injection. TGF-β pathway inhibition delays HSC quiescence induction in WT but not Sparc−/− mice (N = 6 per group and time point; mean and SD; *P < .05; ***P < .005; ****P < .001; unpaired 2-tailed Student t test). (D) p27 mRNA expression in HSCs (Lin−Sca-1+CD48−CD150+CD34−) before and 9 or 10 days after 5-FU. (E) Survival curve of Sparcflox2 and MxCre;Sparcflox2 mice treated with 5-FU at a dose of 150 μg/g at 10-day intervals starting 5 weeks after deletion (N = 8-9 per group; median survival: Sparcflox2 = 45 days, MxCre;Sparcflox2 = 50 days; no significant difference; log-rank [Mantel-Cox] test and Gehan-Breslow-Wilcoxon test). Time points of 5-FU injections are indicated with arrows. (F) Niche cell frequencies of WT and Sparc−/− mice 10 days after 5-FU and at baseline. Niche cells were isolated from bone chips and identified with the indicated markers by flow cytometry (N = 4 per group and time point; mean and SD). (G) SPARC mRNA expression in niche cells of WT mice before and 5 or 10 days after 5-FU (N = 6 per group and time point; mean and SD; *P < .05; **P < .01; ***P < .005; 1-way ANOVA followed by Dunnett’s multiple comparison test). (H) SPARC mRNA expression in hematopoietic progenitors of WT mice before and 5 or 10 days after 5-FU (N = 6 per group and time point; mean and SD; *P < .05; **P < .01; 1-way ANOVA followed by Dunnett’s multiple comparison test).
