CD11c deficiency affects HPSC proliferation and survival in a systemic LPS injection model. (A) Representative flow cytometry plot showing lineage-negative BM cells at different time points post-LPS injection (10 mg/kg IV). (B) Dynamics of LSK and CMP numbers of WT and CD11c^−/− mice after LPS injection. Data are shown as mean ± SEM of 3 to 6 mice per group per time point. Representative flow cytometry plots of LT-HSCs, ST-HSCs, and MPPs are shown. (C) Immunofluorescence staining of progenitor cells in BM. Femurs from WT mice and CD11c^−/− mice (both naive and 4 hours post-LPS) were stained with c-kit (green), DAPI (blue), and laminin (pink). Shown are representative images (full scale bar, 5 mm [in 1 mm increments]). (D-E) Proliferation and apoptosis measurement by Ki67 and active caspase 3 staining. Both WT and CD11c^−/− mice were euthanized at 3 hours after LPS injection. (D) Representative flow cytometry plots of LSK cells. (E) Frequency (top panel) and absolute number (bottom panel) of Ki67⁺, active caspase 3–positive, and Ki67⁺/active caspase 3–positive in LSKs. (F) Z-VAD-fmk treatment. CD11c^−/− mice received either vehicle (5% dimethyl sulfoxide [DMSO] in saline, IP) treatment or Z-VAD (10 mg/kg, dissolved in 5% DMSO in saline, IP) treatment at 1 hour before and 2 hours after LPS injection, and then were euthanized at 6 hours after LPS injection. Total BM cells, lineage-negative cells, LSKs, and CMPs were counted. (G) Volcano plot from RNA-sequencing analysis of LSK cells isolated from WT and CD11c^−/− mice at 4 hours after LPS injection. Data are representative of 2 independent experiments with the same pattern. Error bars indicate ± SEM. Statistical significance was examined by 2-way ANOVA with Bonferroni post hoc analysis (B), with the Student t test (E), and with 1-way ANOVA with Bonferroni post hoc analysis (F). *P < .05; ***P < .001.