1. Tissue plasminogen activator promotes postischemic neutrophil recruitment via its proteolytic and nonproteolytic properties.
- Author
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Uhl B, Zuchtriegel G, Puhr-Westerheide D, Praetner M, Rehberg M, Fabritius M, Hessenauer M, Holzer M, Khandoga A, Fürst R, Zahler S, Krombach F, and Reichel CA
- Subjects
- Animals, Capillary Permeability, Cells, Cultured, Disease Models, Animal, Dose-Response Relationship, Drug, Endothelial Cells metabolism, Fibrinogen metabolism, Fibrinolysin metabolism, Gelatinases metabolism, Hemodynamics, Humans, Male, Mast Cells metabolism, Mice, Mice, Inbred C57BL, Mice, Knockout, Microcirculation, Microvessels metabolism, Microvessels physiopathology, Mutation, Neutrophils drug effects, Neutrophils immunology, Recombinant Proteins administration & dosage, Reperfusion Injury genetics, Reperfusion Injury immunology, Reperfusion Injury physiopathology, Time Factors, Tissue Plasminogen Activator administration & dosage, Tissue Plasminogen Activator deficiency, Tissue Plasminogen Activator genetics, Transendothelial and Transepithelial Migration, Chemotaxis, Leukocyte drug effects, Muscles blood supply, Neutrophil Infiltration drug effects, Neutrophils enzymology, Reperfusion Injury enzymology, Tissue Plasminogen Activator metabolism
- Abstract
Objective: Neutrophil infiltration of the postischemic tissue considerably contributes to organ dysfunction on ischemia/reperfusion injury. Beyond its established role in fibrinolysis, tissue-type plasminogen activator (tPA) has recently been implicated in nonfibrinolytic processes. The role of this serine protease in the recruitment process of neutrophils remains largely obscure., Approach and Results: Using in vivo microscopy on the postischemic cremaster muscle, neutrophil recruitment and microvascular leakage, but not fibrinogen deposition at the vessel wall, were significantly diminished in tPA(-/-) mice. Using cell transfer techniques, leukocyte and nonleukocyte tPA were found to mediate ischemia/reperfusion-elicited neutrophil responses. Intrascrotal but not intra-arterial application of recombinant tPA induced a dose-dependent increase in the recruitment of neutrophils, which was significantly higher compared with stimulation with a tPA mutant lacking catalytic activity. Whereas tPA-dependent transmigration of neutrophils was selectively reduced on the inhibition of plasmin or gelatinases, neutrophil intravascular adherence was significantly diminished on the blockade of mast cell activation or lipid mediator synthesis. Moreover, stimulation with tPA caused a significant elevation in the leakage of fluorescein isothiocyanate dextran to the perivascular tissue, which was completely abolished on neutrophil depletion. In vitro, tPA-elicited macromolecular leakage of endothelial cell layers was abrogated on the inhibition of its proteolytic activity., Conclusions: Endogenously released tPA promotes neutrophil transmigration to reperfused tissue via proteolytic activation of plasmin and gelatinases. As a consequence, tPA on transmigrating neutrophils disrupts endothelial junctions allowing circulating tPA to extravasate to the perivascular tissue, which, in turn, amplifies neutrophil recruitment through the activation of mast cells and release of lipid mediators., (© 2014 American Heart Association, Inc.)
- Published
- 2014
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