Production of stromal cell-derived factor-1 (SDF-1) and expression of CXCR4 in human bone marrow endothelial cells

This study investigated the production of stromal cell-derived factor-1 (SDF-1) and the expression of CXCR4 in human bone marrow endothelial cells (BMECs). Human BMEC cell line BMEC-1 cells expressed SDF-1 mRNA, and conditioned medium induced chemoattraction of CD34+ cells. Migration was not inhibited by pretreating the input cells with pertussis toxin, indicating that the chemoattractive activity was not dependent on SDF-1. Three-day culture of BMEC-1 and primary human BMEC cells produced 1,710 +/- 204 and 1,050 +/- 153 pg/mL SDF-1alpha, respectively, which was much less than primary human BM stromal cells (29,536 +/- 532 pg/mL). By immunohistochemistry, CXCR4 was detected in the endothelial cells lining sinusoids, arterioles, and venules in the bone marrow. However, cultured BMECs and BMEC-1 cells did not express CXCR4 on their surfaces. These results indicate that BMECs produce and release small amounts of SDF-1 and express CXCR4 in vivo only.