Hypotension and inflammatory cytokine gene expression triggered by factor Xa-nitric oxide signaling.
The signaling pathway initiated by factor Xa on vascular endothelial cells was investigated. Factor Xa stimulated a 5- to 10-fold increased release of nitric oxide (NO) in a dose-dependent reaction (0.1-2.5 microG/ml) unaffected by the thrombin inhibitor hirudin but abolished by active site inhibitors, tick anticoagulant peptide, or Glu-Gly-Arg-chloromethyl ketone. In contrast, the homologous clotting protease factor IXa or another endothelial cell ligand, fibrinogen, was ineffective. A factor Xa inter-epidermal growth factor synthetic peptide L (83)FTRKL(88) (G) blocking ligand binding to effector cell protease receptor-1 inhibited NO release by factor Xa in a dose-dependent manner, whereas a control scrambled peptide KFTGRLL was ineffective. Catalytically active factor Xa induced hypotension in rats and vasorelaxation in the isolated rat mesentery, which was blocked by the NO synthase inhibitor L-N(G)-nitroarginine methyl ester (L-NAME) but not by D-NAME. Factor Xa/NO signaling also produced a dose-dependent endothelial cell release of interleukin 6 (range 0.55-3.1 ng/ml) in a reaction inhibited by L-NAME and by the inter-epidermal growth factor peptide Leu(83)-Leu(88) but unaffected by hirudin. Maximal induction of interleukin 6 mRNA required a brief, 30-min stimulation with factor Xa, unaffected by subsequent addition of tissue factor pathway inhibitor. These data suggest that factor Xa-induced NO release modulates endothelial cell-dependent vasorelaxation and cytokine gene expression. This pathway requiring factor Xa binding to effector cell protease receptor-1 and a secondary step of ligand-dependent proteolysis may preserve an anti-thrombotic phenotype of endothelium but also trigger acute phase responses during activation of coagulation in vivo.
Papapetropoulos
A
A
Department of Pharmacology, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, CT 06536, USA.
Piccardoni
P
P
Cirino
G
G
Bucci
M
M
Sorrentino
R
R
Cicala
C
C
Johnson
K
K
Zachariou
V
V
Sessa
W C
WC
Altieri
D C
DC
D000818:Animals; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D015951:Factor Xa / Q000494:pharmacology / Q000502:physiology*; D005340:Fibrinogen / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D007022:Hypotension; D007249:Inflammation; D015850:Interleukin-6 / Q000096:biosynthesis*; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D009569:Nitric Oxide / Q000502:physiology*; D016133:Polymerase Chain Reaction; D051381:Rats; D017208:Rats, Wistar; D013152:Splanchnic Circulation; D013237:Stereoisomerism; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D014471:Umbilical Veins
D016207:Cytokines; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D006632:Histamine; D005340:Fibrinogen; D015951:Factor Xa; D019331:NG-Nitroarginine Methyl Ester