1. Circulating soluble P-selectin must dimerize to promote inflammation and coagulation in mice.
- Author
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Panicker SR, Mehta-D'souza P, Zhang N, Klopocki AG, Shao B, and McEver RP
- Subjects
- Animals, Antibodies pharmacology, CD18 Antigens genetics, CD18 Antigens immunology, CHO Cells, Cell Adhesion drug effects, Cricetulus, Disulfides chemistry, Extracellular Traps drug effects, Gene Expression Regulation, Immunoglobulin Fc Fragments blood, Immunoglobulin Fc Fragments genetics, Inflammation, Mice, Mice, Inbred C57BL, Mice, Transgenic, Neutrophils drug effects, Neutrophils pathology, P-Selectin chemistry, P-Selectin genetics, P-Selectin immunology, Protein Domains, Protein Multimerization, Recombinant Fusion Proteins blood, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins immunology, Signal Transduction, Thromboplastin genetics, Thromboplastin immunology, Thrombosis immunology, Thrombosis pathology, Vena Cava, Inferior pathology, Extracellular Traps immunology, Neutrophils immunology, P-Selectin blood, Thrombosis genetics, Vena Cava, Inferior immunology
- Abstract
Leukocyte adhesion to P-selectin on activated platelets and endothelial cells induces shedding of the P-selectin ectodomain into the circulation. Plasma soluble P-selectin (sP-selectin) is elevated threefold to fourfold in patients with cardiovascular disease. Circulating sP-selectin is thought to trigger signaling in leukocytes that directly contributes to inflammation and thrombosis. However, sP-selectin likely circulates as a monomer, and in vitro studies suggest that sP-selectin must dimerize to induce signaling in leukocytes. To address this discrepancy, we expressed the entire ectodomain of mouse P-selectin as a monomer (sP-selectin) or as a disulfide-linked dimer fused to the Fc portion of mouse immunoglobulin G (sP-selectin-Fc). Dimeric sP-selectin-Fc, but not monomeric sP-selectin, triggered integrin-dependent adhesion of mouse leukocytes in vitro. Antibody-induced oligomerization of sP-selectin or sP-selectin-Fc was required to trigger formation of neutrophil extracellular traps. Injecting sP-selectin-Fc, but not sP-selectin, into mice augmented integrin-dependent adhesion of neutrophils in venules, generated tissue factor-bearing microparticles, shortened plasma-clotting times, and increased thrombus frequency in the inferior vena cava. Furthermore, transgenic mice that overexpressed monomeric sP-selectin did not exhibit increased inflammation or thrombosis. We conclude that elevated plasma sP-selectin is a consequence rather than a cause of cardiovascular disease., (© 2017 by The American Society of Hematology.)
- Published
- 2017
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