title: The IP-10 chemokine binds to a specific cell surface heparan sulfate site shared with platelet factor 4 and inhibits endothelial cell proliferation.
abstract: IP-10 is a member of the chemokine family of cytokines and is induced in a variety of cells in response to interferon gamma and lipopolysaccharide. The self-aggregation common to many chemokines, including IP-10, has hindered the identification of a specific IP-10 receptor. Using an IP-10 alkaline phosphatase fusion protein that fortuitously blocks this self-aggregation, we have identified an IP-10 binding site on a variety of cells including endothelial, epithelial, and hematopoietic cells. This binding site has a Kd of 25 nM, is inhibited by recombinant murine or human IP-10, and is dependent on the presence of cell surface heparan sulfate proteoglycans (HSPG). This conclusion is based on the findings that IP-10 binding to cells is: (a) inhibited by heparin and heparan sulfate; (b) sensitive to a 1 M NaCl wash; (c) eliminated by treatment with heparinase and trypsin; and (d) absent on mutant CHO cells that do not express cell surface HSPG. Platelet factor 4 (PF4), but not IL-8, monocyte chemoattractant protein-1, RANTES, monocyte inflammatory protein (MIP)-1 alpha, or MIP-1 beta, can compete effectively with IP-10 for binding to the cell surface. Furthermore, IP-10 shares with PF4 the ability to inhibit endothelial cell proliferation (IC50 = 150 nM). These studies demonstrate specificity in the interaction of chemokines and HSPG, and they define IP-10 and PF4 as a distinct subset of chemokines sharing an HSPG-binding site and angiostatic properties.
authors.affiliation: Department of Genetics, Harvard Medical School, Howard Hughes Medical Institute, Boston, Massachusetts 02115, USA.
authors.forename: A D
authors.initials: AD
authors.lastname: Luster
authors.forename: S M
authors.initials: SM
authors.lastname: Greenberg
authors.forename: P
authors.initials: P
authors.lastname: Leder
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D054357:Chemokine CXCL10; D019743:Chemokines, CXC; D006224:Cricetinae; D003412:Cricetulus; D016207:Cytokines / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D018076:DNA, Complementary / Q000235:genetics; D003864:Depression, Chemical; D003871:Dermatan Sulfate / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects*; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D006025:Glycosaminoglycans / Q000494:pharmacology; D006493:Heparin / Q000494:pharmacology; D006497:Heparan Sulfate / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D007962:Leukocytes / Q000378:metabolism; D016131:Lymphocyte Subsets / Q000378:metabolism; D008223:Lymphoma / Q000473:pathology; D051379:Mice; D008969:Molecular Sequence Data; D010954:Plasmacytoma / Q000473:pathology; D010978:Platelet Factor 4 / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D011817:Rabbits; D011956:Receptors, Cell Surface / Q000378:metabolism*; D019707:Receptors, Chemokine; D011993:Recombinant Fusion Proteins / Q000378:metabolism / Q000494:pharmacology; D013047:Specific Pathogen-Free Organisms; D014407:Tumor Cells, Cultured
chemical_list: D002118:Calcium; D054357:Chemokine CXCL10; D019743:Chemokines, CXC; D016207:Cytokines; D018076:DNA, Complementary; D003871:Dermatan Sulfate; D006025:Glycosaminoglycans; D006493:Heparin; D006497:Heparan Sulfate; D010978:Platelet Factor 4; D011956:Receptors, Cell Surface; D019707:Receptors, Chemokine; D011993:Recombinant Fusion Proteins