Expression of multiple functional chemokine receptors and monocyte chemoattractant protein-1 in human neurons

Functional chemokine receptors and chemokines are expressed by glial cells within the CNS, though relatively little is known about the patterns of neu ronal chemokine receptor expression and function. We developed monoclonal a ntibodies to the CCR1, CCR2, CCR3, CCR6, CXCR2, CXCR3 and CXCR4 chemokine r eceptors to study their expression in human fetal neurons cultured from bra in tissue as well as the clonally derived NT2.N human neuronal cell line (N Tera 2/cl.D1). Specific monoclonal antibody labeling demonstrated expressio n of CCR2, CXCR2, CXCR3 and CXCR4 on neurons from both sources. Co-labeling studies revealed strong expression of CXCR3 and CXCR4 on both dendritic an d axonal processes, with a weaker expression of CXCR2 and CCR2. Reverse tra nscriptase-polymerase chain reaction analysis of pure NT2.N neurons confirm ed RNA expression for CCR2, CXCR2 CXCR3 and CXCR4. No changes in the neuron al labeling pattern of chemokine receptor expression were noted when NT2.N neurons were grown on a supporting layer of astrocytes, again consistent wi th similar patterns seen in primary human fetal brain cultures. Analysis of single-cell calcium transients revealed a robust response to stromal deriv ed factor-lot (CXCR4) and melanocyte growth-stimulating activity (CXCR2), a nd variable response to monocyte chemoattractant protein-1 (CCR2) or interf eron-gamma inducible protein-10 (CXCR3). Finally, we detected the release o f monocyte chemoattractant protein-1 from pure cultures of NT2.N neurons, b ut not undifferentiated NT2 cells. These data indicate that individual neurons may not only co-express multipl e functional chemokine receptors, but also that neurons themselves produce chemokines which may influence cellular function within the central nervous system. (C) 2000 IBRO. Published by Elsevier Science Ltd.