title: Factor Xa and thrombin evoke additive calcium and proinflammatory responses in endothelial cells subjected to coagulation.
abstract: Endothelial cells react to factor Xa and thrombin by proinflammatory responses. It is unclear how these cells respond under physiological conditions, where the serine proteases factor VIIa, factor Xa and thrombin are all simultaneously generated, as in tissue factor-driven blood coagulation. We studied the Ca(2+) signaling and downstream release of interleukins (ILs), induced by these proteases in monolayers of human umbilical vein endothelial cells. In single cells, factor Xa, but not factor VIIa, complexed with tissue factor, evoked a greatly delayed, oscillatory Ca(2+) response, which relied on its catalytic activity and resembled that of SLIGRL, a peptide specifically activating the protease-activated receptor 2 (PAR2). Thrombin even at low concentrations evoked a rapid, mostly non-oscillating Ca(2+) response through activation of PAR1, which reinforced the factor Xa response. The additive Ca(2+) signals persisted, when factor X and prothrombin were activated in situ, or in the presence of plasma that was triggered to coagulate with tissue factor. Further, thrombin reinforced the factor Xa-induced production of IL-8, but not of IL-6. Both interleukins were produced in the presence of coagulating plasma. In conclusion, under coagulant conditions, factor Xa and thrombin appear to contribute in different and additive ways to the Ca(2+)-mobilizing and proinflammatory reactions of endothelial cells. These data provide first evidence that these serine proteases trigger distinct signaling modules in endothelium that is activated by plasma coagulation.
authors.affiliation: Deparment of Biochemistry, CARIM, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands. valery.daubie@ulb.ac.be
authors.forename: Valéry
authors.initials: V
authors.lastname: Daubie
authors.forename: Sandra
authors.initials: S
authors.lastname: Cauwenberghs
authors.forename: Nicole H M
authors.initials: NH
authors.lastname: Senden
authors.forename: Roland
authors.initials: R
authors.lastname: Pochet
authors.forename: Theo
authors.initials: T
authors.lastname: Lindhout
authors.forename: Wim A
authors.initials: WA
authors.lastname: Buurman
authors.forename: Johan W M
authors.initials: JW
authors.lastname: Heemskerk
mesh_terms: D001777:Blood Coagulation / Q000502:physiology; D020013:Calcium Signaling / Q000187:drug effects*; D002478:Cells, Cultured; D004357:Drug Synergism; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism*; D015951:Factor Xa / Q000008:administration & dosage* / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D018836:Inflammation Mediators / Q000378:metabolism*; D015850:Interleukin-6 / Q000096:biosynthesis; D016209:Interleukin-8 / Q000096:biosynthesis; D009842:Oligopeptides / Q000494:pharmacology; D018179:Receptors, Thrombin / Q000819:agonists; D013917:Thrombin / Q000008:administration & dosage* / Q000378:metabolism
chemical_list: D018836:Inflammation Mediators; D015850:Interleukin-6; D016209:Interleukin-8; D009842:Oligopeptides; D018179:Receptors, Thrombin; C099570:seryl-leucyl-isoleucyl-glycyl-arginyl-leucine; D013917:Thrombin; D015951:Factor Xa