Hematopoietic stem and progenitor cells in SCD. (A) Townes SS mice were analyzed for the peripheral blood hematopoietic stem and progenitor cell population marked by Lin^–Sca1⁺c-Kit⁺Flt3^– represented as fold change in number per mL blood among SS mice relative to SA mice (N = 7-8 mice). (B) Bone marrow HSC frequency was assessed by flow cytometry for Lin^–Sca1⁺c-Kit⁺CD48^–CD150⁺ (N = 6-7 mice). (C) Representative histogram and images of bone marrow hematopoietic cells from SA and SS mice gated on live cells and stained by Lineage-CD150⁺γH2AX⁺ by ImageStream analysis. (D) Quantification by ImageStream of the mean fluorescence intensity (MFI) of γH2AX in sickle mouse HSCs normalized to control HSCs (N = 5 mice). (E) Representative histogram and images of bone marrow hematopoietic cells from SA and SS mice gated on live cells and stained by Lineage-CD150⁺ and DCFDA by ImageStream analysis. (F) Quantification of the frequency of HSCs containing ROS in sickle and control bone marrow by ImageStream (N = 4 mice). (G) Quantification of the mean fluorescence intensity (MFI) of ROS in sickle and control bone marrow HSCs by ImageStream (N = 4 mice) presented as fold change of SS compared with SA. Data were analyzed with a 2-tailed, unpaired Student t test. Data are presented as mean ± standard error of the mean. *P ≤ .05, **P ≤ .01, ***P ≤ .001, ****P ≤ .0001.