Thrombin receptor 14-amino acid peptide mediates endothelial hyperadhesivity and neutrophil adhesion by P-selectin-dependent mechanism.
Thrombin cleaves its receptor at arginine-41, resulting in the generation of a new receptor NH2-terminus with the sequence SFLLRNPNDKYEPF. This peptide (TRP-14) may signal a variety of thrombin's responses. We examined the effects of TRP-14 in inducing endothelial cell hyperadhesivity and neutrophil (PMN) adhesion to endothelial cell monolayers. Human umbilical vein endothelial cells (HUVECs) challenged with TRP-14 (10(-4) to 10(-5) M) produced concentration-dependent increases in endothelial adhesivity to PMN. In contrast, position 1 to 2 inverted peptide (FSLLRNPNDKYEPF) did not induce the response. The adhesion response was transient; that is, PMN adhesion increased within 15 minutes and decreased by 75 minutes after TRP-14 challenge of HUVECs. The transient endothelial adhesiveness paralleled the time course of P-selectin expression. TRP-14-induced release of P-selectin from intracellular stores may be a critical determinant of the response since treatment of endothelial cells with anti-P-selectin monoclonal antibody (mAb) G1 prevented the increase in PMN adhesion. Control nonneutralizing anti-P-selectin mAb S12 and mAb RR1/1 directed against intercellular adhesion molecule-1 (ICAM-1) on HUVECs were ineffective. The results indicate that the "tethered ligand" of the thrombin receptor created by the proteolytic action of thrombin on its receptor (i.e., TRP-14) signals increased endothelial adhesiveness by a P-selectin-dependent mechanism. Thrombin-induced PMN adhesion may involve formation of a new NH2-terminus of the endothelial thrombin receptor with the sequence SFLLRNPNDKYEPF followed by activation of endothelial second messenger pathways and the transient expression of P-selectin.
Sugama
Y
Y
Department of Physiology and Cell Biology, Albany Medical College, Union University, NY 12208.
Malik
A B
AB
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD; D001665:Binding Sites; D015815:Cell Adhesion Molecules; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000502:physiology*; D006801:Humans; D009504:Neutrophils / Q000502:physiology*; D019007:P-Selectin; D010980:Platelet Membrane Glycoproteins / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000502:physiology*; D018179:Receptors, Thrombin; D013917:Thrombin / Q000502:physiology*; D013997:Time Factors; D000267:Tissue Adhesions
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D015815:Cell Adhesion Molecules; D019007:P-Selectin; D010980:Platelet Membrane Glycoproteins; D011956:Receptors, Cell Surface; D018179:Receptors, Thrombin; D013917:Thrombin