S1P induces SDF-1 secretion from BM Nestin⁺ stromal stem and progenitor cells during mobilization. (A) A representative histogram of the percentage of S1P₁ positive cells within the CD45⁺ and CD45⁻ populations in steady-state conditions. (B) A representative histogram of the percentage of S1P₁ positive cells within the Nestin⁺/CD45⁻ population in steady-state conditions. (C) Immunofluorescence staining of total BM cells from Nestin-GFP mice for SDF-1 expression on stimulation with 1μM S1P/vehicle for 1 hour. (D,G) Mice were injected with PBS or administered with glucose in the drinking water (control), injected with FTY720 (single intraperitoneal injection 1.5 hours and 24 hours before sacrifice) or administered with DOP (together with glucose for 3 days in the drinking water). (D) SDF-1 ELISA levels in BM fluids are shown. (E) SDF-1 ELISA levels in the BM fluids of PBS (control), G-CSF (single subcutaneous injection and evaluated after 30 minutes) or G-CSF+FTY720 (coinjection of subcutaneous G-CSF and intraperitoneal FTY720 and evaluated after 30 minutes) mice are presented. (F) Immunofluorescence staining of total BM cells from Nestin-GFP mice for SDF-1 expression on stimulation with PBS, 100 ng/mL AMD3100 for 1 hour, 1μM FTY720 for 1.5 hours alone or 30 minutes before AMD3100 addition. (G) The levels of uPA activity are shown. Indicated values are presented as mean ± SE in 2-3 independent experiments, a total of 4-6 mice in each group (*P < .05, **P < .01).