Figure 3.
Factor Xa/NO induction of IL-6 release in HUVEC. (A) IL-6 release by HUVEC stimulated with increasing concentrations of factor Xa (▪), DEGR-factor Xa (•), or fibrinogen (□) was determined by ELISA after a 12-h culture at 37°C. (B) Effect of the factor Xa-derived inter-EGF peptide Leu83–Leu88 (▪) or control scrambled peptide KFTGRLL (□) on IL-6 release induced by 1 μg/ml factor Xa (peptide concentrations are in μM). Statistical analysis revealed no significant differences in the amount of IL-6 released in the presence of control scrambled peptide KFTGRLL. NO inhibitor l-NAME and control inactive d-NAME were preincubated with HUVEC in the presence or in the absence of the indicated increasing concentrations of the NO donor, NOC 15, before factor Xa stimulation and determination of IL-6 release. (C) Effect of increasing concentrations of TFPI (0.5–50 μg/ml) added 1 h after HUVEC stimulation with factor Xa on IL-6 release. (D) Time course of IL-6 mRNA induction following factor Xa stimulation of HUVEC. Densitometric quantitation of radioactive bands (fold induction) was normalized on control hybridization with glyceraldehyde-3-phosphate dehydrogenase.