Lippincott Williams & Wilkins, Inc., Philadelphia
Characterization of Binding Sites for Chemokines MCP-1 and MIP-1α on Human Brain Microvessels
Article first published online: 4 JAN 2002
Journal of Neurochemistry
Volume 75, Issue 5, pages 1898–1906, November 2000
How to Cite
Andjelkovic, A. V. and Pachter, J. S. (2000), Characterization of Binding Sites for Chemokines MCP-1 and MIP-1α on Human Brain Microvessels. Journal of Neurochemistry, 75: 1898–1906. doi: 10.1046/j.1471-4159.2000.0751898.x
Abbreviations used: BBB, blood-brain barrier; biot-rh, biotinylated recombinant human; GFAP, glial fibrillary acidic protein; IL-8, interleukin-8; MCP-1, monocyte chemoattractant protein-1; MIP-1α, macrophage inflammatory protein-1α; PBS, phosphate-buffered saline; UEA-1, Ulex europaeus agglutinin-1.
- Issue published online: 4 JAN 2002
- Article first published online: 4 JAN 2002
- Chemokine receptors;
- Endothelial cells
Abstract: The presence of binding sites for the β chemokines monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1α (MIP-1α) has recently been identified on human brain microvessels. We extend these findings in this report to reveal that such sites exemplify characteristics of the recognized major receptors for MCP-1 and MIP-1α: CCR2, and CCR1 and CCR5, respectively. Specifically, labeled MCP-1 binding to isolated brain microvessels was inhibited by unlabeled MCP-1 and MCP-3, the latter another CCR2 ligand, but not by MIP-1α. Inhibition of labeled MIP-1α binding was achieved with unlabeled MIP-1α and RANTES, the latter a β chemokine that binds to both CCR1 and CCR5, but not by MCP-1. Labeled MIP-1α binding was also antagonized by unlabeled MCP-3, which is also recognized by CCR1, and MIP-1β, which is a ligand for CCR5. Labeled MCP-1 and MIP-1α were further observed to be internalized within the endothelial cells of brain microvessels, following their binding to the microvascular surface at 37°C. Additionally, exposure of microvessels to unlabeled MCP-1 or MIP-1α was accompanied by the initial loss and subsequent recovery of surface binding sites for these chemokines, which occurred on a time scale consistent with ligand-induced endocytosis and recycling. These collective features bear striking similarity to those that characterize interactions of MCP-1 and MIP-1α with their receptors on leukocytes and underscore the concept of cognate chemokine receptors on brain microvascular endothelium.