Figure 1: Factors favoring homing of HPSCs in the bone marrow. (A) Chemotactic factors independent of the SDF-1/CXCR4 axis gradient. (B) Triggering or modulating factors of the SDF-1/CXCR4 axis. HSPC: hematopoietic stem/progenitor cells; C3a: complement fraction C3a; C1q: complement fraction C1q; PMVs: platelet-derived microvesicles; HA: hyaluronic acid; TH: thrombin; MMP-2: metalloproteinase-2; MMP-9: metalloproteinase-9; MT1-MMP: membrane type-1 matrix metalloproteinase; SP1: sphingosine-1-phosphate; CP1: ceramide-1-phosphate.