VEGF-A has no chemotactic effect on HSPCs in vitro. Chemotaxis assay with Kit⁺ enriched BM cells from naive C57BL/6 mice incubated for 4 hours at 37°C in the presence of 50 ng/mL CXCL12 in the bottom chamber or 100 ng/mL mouse VEGF-A in the bottom chamber or in the top insert. The percentage of LKS⁺ cells (A) and LKS⁺CD48⁻CD150⁺ HSCs (B) that migrated to the bottom chamber was measured by flow cytometry. Data are from 2 pooled experiments performed several weeks apart. Each symbol is a well. Bars are means ± standard deviation. Each individual group with CXCL12 in the bottom well was significantly different from each group without CXCL12. ****P < 10⁻⁴, ANOVA.