Glial and neuronal cells express functional chemokine receptor CXCR4 and its natural ligand stromal cell-derived factor 1

Chemokines are a family of proteins that chemoattract and activate cells by interacting with specific receptors on the surface of their targets. The c hemokine stromal cell-derived factor 1, (SDF1), binds to the seven-transmem brane G protein-coupled CXGR4 receptor and acts to modulate cell migration, differentiation, and proliferation, CXCR4 and SDF1 are reported to be expr essed in various tissues including brain. Here we show that SDF1 and CXCR4 are expressed in cultured cortical type I rat astrocytes, cortical neurons, and cerebellar granule cells. In cortical astrocytes, prolonged treatment with lipopolysaccharide induced an increase of SDF1 expression and a down-r egulation of CXGR4, whereas treatment with phorbol esters did not affect SD F1 expression and down-modulated CXCR4 receptor expression. We also demonst rated the ability of human SDF1 alpha (hSDF1 alpha) to increase the intrace llular calcium level in cultured astrocytes and cortical neurons, whereas i n the same conditions, cerebellar granule cells did not modify their intrac ellular calcium concentration. Furthermore, in cortical astrocytes, the sim ultaneous treatment of hSDF1 alpha with the HIV-1 capside glycoprotein gp12 0 inhibits the cyclic AMP formation induced by forskolin treatment.