title: Fibrinolytic cross-talk: a new mechanism for plasmin formation.
abstract: Fibrinolysis and pericellular proteolysis depend on molecular coassembly of plasminogen and its activator on cell, fibrin, or matrix surfaces. We report here the existence of a fibrinolytic cross-talk mechanism bypassing the requirement for their molecular coassembly on the same surface. First, we demonstrate that, despite impaired binding of Glu-plasminogen to the cell membrane by epsilon-aminocaproic acid (epsilon-ACA) or by a lysine-binding site-specific mAb, plasmin is unexpectedly formed by cell-associated urokinase (uPA). Second, we show that Glu-plasminogen bound to carboxy-terminal lysine residues in platelets, fibrin, or extracellular matrix components (fibronectin, laminin) is transformed into plasmin by uPA expressed on monocytes or endothelial cell-derived microparticles but not by tissue-type plasminogen activator (tPA) expressed on neurons. A 2-fold increase in plasmin formation was observed over activation on the same surface. Altogether, these data indicate that cellular uPA but not tPA expressed by distinct cells is specifically involved in the recognition of conformational changes and activation of Glu-plasminogen bound to other biologic surfaces via a lysine-dependent mechanism. This uPA-driven cross-talk mechanism generates plasmin in situ with a high efficiency, thus highlighting its potential physiologic relevance in fibrinolysis and matrix proteolysis induced by inflammatory cells or cell-derived microparticles.
authors.affiliation: Inserm, U919, Caen, France.
authors.forename: Tiphaine
authors.initials: T
authors.lastname: Dejouvencel
authors.forename: Loïc
authors.initials: L
authors.lastname: Doeuvre
authors.forename: Romaric
authors.initials: R
authors.lastname: Lacroix
authors.forename: Laurent
authors.initials: L
authors.lastname: Plawinski
authors.forename: Françoise
authors.initials: F
authors.lastname: Dignat-George
authors.forename: H Roger
authors.initials: HR
authors.lastname: Lijnen
authors.forename: Eduardo
authors.initials: E
authors.lastname: Anglés-Cano
mesh_terms: D015119:Aminocaproic Acid / Q000494:pharmacology; D000818:Animals; D000933:Antifibrinolytic Agents / Q000494:pharmacology; D002450:Cell Communication / Q000502:physiology; D002478:Cells, Cultured; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D005341:Fibrinolysin / Q000378:metabolism*; D005342:Fibrinolysis / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D051379:Mice; D010958:Plasminogen / Q000378:metabolism; D010960:Plasminogen Activators / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D020239:Receptor Cross-Talk / Q000187:drug effects / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism
chemical_list: D000933:Antifibrinolytic Agents; D010958:Plasminogen; D010960:Plasminogen Activators; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator; D015119:Aminocaproic Acid