HSPC expansion and increased LTR-HSC capacity is dependent on c-Kit up-regulation and activation by FGF-2. C57BL/6 mice were treated with PBS or FGF-2 (n > 7). (A) c-Kit expression on Lin⁻/Sca-1⁺ cells was determined by flow cytometry. (B) c-Kit expression on SLAM cells was determined by flow cytometry. (C) Representative flow cytometric analysis of p-STAT5 levels in SKL cells. (D) Representative flow cytometric analysis of p-SHP2 levels in SKL cells. Numbers indicate the percentage of p-SHP2^high–expressing SKL cells. C57BL/6 WT or W^v/W^v mice were treated with either PBS or FGF-2 (n = 4). (E) BM cellularity per femur and tibia. (F) Percentage of BM SKL cells as determined by flow cytometry. (G) Percentage of BM CD34⁻/SKL as determined by flow cytometry. (H) Percentage of SKL-expressing ROS^high cells as determined by flow cytometry. C57BL/6 WT or W^v/W^v mice were treated with either PBS or FGF-2 or FGF-2 combined with N-acetyl-cysteine (NAC)/rapamycin (n = 4). (I) Percentage of BM SKL cells as determined by flow cytometry. (J) Percentage of BM CD34⁻/SKL as determined by flow cytometry. *P < .05; **P < .01. Data shown are means ± SEM.