title: Structural recognition of a novel fibrinogen gamma chain sequence (117-133) by intercellular adhesion molecule-1 mediates leukocyte-endothelium interaction.
abstract: In addition to its role in hemostasis, fibrinogen is obligatorily required to mount competent inflammatory responses in vivo. A molecular prerequisite of fibrinogen-dependent inflammation may reside in its ability to associate with intercellular adhesion molecule-1 (ICAM-1), and enhance monocyte adhesion to endothelium by bridging the two cell types. Structure-function characterization of the novel ICAM-1 recognition of fibrinogen was carried out by synthetic peptidyl mimicry of the fibrinogen gamma chain. A novel peptide sequence, N117NQ-KIVNLKEKVAQLEA133, designated gamma 3, dose-dependently inhibited (IC50 approximately 20-40 micrograms/ml) binding of 125I-fibrinogen to endothelial cells or ICAM-1-expressing B lymphoblastoid Daudi cells. In contrast, none of the previously identified vascular cell fibrinogen interacting sequences was effective. Increasing concentrations of gamma 3 completely inhibited fibrinogen-mediated adhesion of peripheral blood mononuclear cells or vitamin D3-differentiated monocytic HL-60 cells to endothelium, but did not affect leukocyte-endothelium interaction in the absence of fibrinogen. 125I-Labeled gamma 3 bound specifically and saturably to genetically engineered ICAM-1 transfectants, but not to control non-transfected cells, and associated with ICAM-1 on cytokine-activated endothelium with a Kd of 34 microM. Consistent with functional recognition of ICAM-1, immobilized gamma 3 supported adhesion of JY lymphoblasts in a dose-dependent reaction inhibited by monoclonal antibodies to ICAM-1. We conclude that a novel fibrinogen gamma 3 sequence N117NQKIVNLKEKVAQLEA133 binds to ICAM-1 and modulates ICAM-1-dependent adhesion. These findings define the structural basis of fibrinogen:ICAM-1 recognition and provide a potential selective target for inhibiting fibrinogen-dependent inflammatory responses.
authors: Boyer Center for Molecular Medicine, Department of Pathology, Yale University School of Medicine, New Haven, Connecticut 06536.
authors: D C
authors: DC
authors: Altieri
authors: A
authors: A
authors: Duperray
authors: J
authors: J
authors: Plescia
authors: G B
authors: GB
authors: Thornton
authors: L R
authors: LR
authors: Languino
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D002448:Cell Adhesion; D002478:Cells, Cultured; D006224:Cricetinae; D004730:Endothelium, Vascular / Q000166:cytology*; D005340:Fibrinogen / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism*; D007962:Leukocytes / Q000166:cytology*; D018716:Molecular Mimicry; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D013329:Structure-Activity Relationship
chemical_list: D010446:Peptide Fragments; D018799:Intercellular Adhesion Molecule-1; D005340:Fibrinogen