Abstract
Generation of coagulation factor Xa by the intrinsic pathway protease complex is essential for normal activation of the coagulation cascade in vivo. Monocytes and platelets provide membrane sites for assembly of components of this protease complex, factors IXa and VIII. Under biologically relevant conditions, expression of functional activity by this complex is associated with activation of factor VIII to VIIIa. In the present studies, autocatalytic regulatory pathways operating on monocyte and platelet membranes were investigated by comparing the cofactor function of thrombin-activated factor VIII to that of factor Xa-activated factor VIII. Reciprocal functional titrations with purified human factor VIII and factor IXa were performed at fixed concentrations of human monocytes, CaCl2, factor X, and either factor IXa or factor VIII. Factor VIII was preactivated with either thrombin or factor Xa, and reactions were initiated by addition of factor X. Rates of factor X activation were measured using chromogenic substrate specific for factor Xa. The K1/2 values, i.e., concentration of factor VIIIa at which rates were half maximal, were 0.96 nM with thrombin- activated factor VIII and 1.1 nM with factor Xa-activated factor VIII. These values are close to factor VIII concentration in plasma. The Vsat, i.e., rates at saturating concentrations of factor VIII, were 33.3 and 13.6 nM factor Xa/min, respectively. The K1/2 and Vsat values obtained in titrations with factor IXa were not significantly different from those obtained with factor VIII. In titrations with factor X, the values of Michaelis-Menten coefficients (Km) were 31.7 nM with thrombin- activated factor VIII, and 14.2 nM with factor Xa-activated factor VIII. Maximal rates were 23.4 and 4.9 nM factor Xa/min, respectively. The apparent catalytic efficiency was similar with either form of factor VIIIa. Kinetic profiles obtained with platelets as a source of membrane were comparable to those obtained with monocytes. These kinetic profiles are consistent with a 1:1 stoichiometry for the functional interaction between cofactor and enzyme on the surface of monocytes and platelets. Taken together, these results indicate that autocatalytic pathways connecting the extrinsic, intrinsic, and common coagulation pathways can operate efficiently on the monocyte membrane.
Full Text
The Full Text of this article is available as a PDF (1.5 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Ahmad S. S., Rawala-Sheikh R., Walsh P. N. Comparative interactions of factor IX and factor IXa with human platelets. J Biol Chem. 1989 Feb 25;264(6):3244–3251. [PubMed] [Google Scholar]
- Ahmad S. S., Rawala-Sheikh R., Walsh P. N. Platelet receptor occupancy with factor IXa promotes factor X activation. J Biol Chem. 1989 Nov 25;264(33):20012–20016. [PubMed] [Google Scholar]
- BLIGH E. G., DYER W. J. A rapid method of total lipid extraction and purification. Can J Biochem Physiol. 1959 Aug;37(8):911–917. doi: 10.1139/o59-099. [DOI] [PubMed] [Google Scholar]
- Eaton D., Rodriguez H., Vehar G. A. Proteolytic processing of human factor VIII. Correlation of specific cleavages by thrombin, factor Xa, and activated protein C with activation and inactivation of factor VIII coagulant activity. Biochemistry. 1986 Jan 28;25(2):505–512. doi: 10.1021/bi00350a035. [DOI] [PubMed] [Google Scholar]
- Edwards R. L., Rickles F. R. The role of human T cells (and T cell products) for monocyte tissue factor generation. J Immunol. 1980 Aug;125(2):606–609. [PubMed] [Google Scholar]
- English D., Andersen B. R. Single-step separation of red blood cells. Granulocytes and mononuclear leukocytes on discontinuous density gradients of Ficoll-Hypaque. J Immunol Methods. 1974 Aug;5(3):249–252. doi: 10.1016/0022-1759(74)90109-4. [DOI] [PubMed] [Google Scholar]
- Gilbert G. E., Furie B. C., Furie B. Binding of human factor VIII to phospholipid vesicles. J Biol Chem. 1990 Jan 15;265(2):815–822. [PubMed] [Google Scholar]
- Levy G. A., Edgington T. S. Lymphocyte cooperation is required for amplification of macrophage procoagulant activity. J Exp Med. 1980 May 1;151(5):1232–1244. doi: 10.1084/jem.151.5.1232. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Li C. Y., Lam K. W., Yam L. T. Esterases in human leukocytes. J Histochem Cytochem. 1973 Jan;21(1):1–12. doi: 10.1177/21.1.1. [DOI] [PubMed] [Google Scholar]
- Lollar P., Knutson G. J., Fass D. N. Activation of porcine factor VIII:C by thrombin and factor Xa. Biochemistry. 1985 Dec 31;24(27):8056–8064. doi: 10.1021/bi00348a033. [DOI] [PubMed] [Google Scholar]
- McGee M. P., Devlin R., Saluta G., Koren H. Tissue factor and factor VII messenger RNAs in human alveolar macrophages: effects of breathing ozone. Blood. 1990 Jan 1;75(1):122–127. [PubMed] [Google Scholar]
- McGee M. P., Li L. C. Functional difference between intrinsic and extrinsic coagulation pathways. Kinetics of factor X activation on human monocytes and alveolar macrophages. J Biol Chem. 1991 May 5;266(13):8079–8085. [PubMed] [Google Scholar]
- McGee M. P., Rothberger H. Assembly of the prothrombin activator complex on rabbit alveolar macrophage high-affinity factor Xa receptors. A kinetic study. J Exp Med. 1986 Dec 1;164(6):1902–1914. doi: 10.1084/jem.164.6.1902. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McGee M. P., Wallin R., Wheeler F. B., Rothberger H. Initiation of the extrinsic pathway of coagulation by human and rabbit alveolar macrophages: a kinetic study. Blood. 1989 Oct;74(5):1583–1590. [PubMed] [Google Scholar]
- Nesheim M. E., Pittman D. D., Wang J. H., Slonosky D., Giles A. R., Kaufman R. J. The binding of 35S-labeled recombinant factor VIII to activated and unactivated human platelets. J Biol Chem. 1988 Nov 5;263(31):16467–16470. [PubMed] [Google Scholar]
- Neuenschwander P., Jesty J. A comparison of phospholipid and platelets in the activation of human factor VIII by thrombin and factor Xa, and in the activation of factor X. Blood. 1988 Nov;72(5):1761–1770. [PubMed] [Google Scholar]
- Phillips D. R., Charo I. F., Parise L. V., Fitzgerald L. A. The platelet membrane glycoprotein IIb-IIIa complex. Blood. 1988 Apr;71(4):831–843. [PubMed] [Google Scholar]
- Rawala-Sheikh R., Ahmad S. S., Ashby B., Walsh P. N. Kinetics of coagulation factor X activation by platelet-bound factor IXa. Biochemistry. 1990 Mar 13;29(10):2606–2611. doi: 10.1021/bi00462a025. [DOI] [PubMed] [Google Scholar]
- Rosing J., van Rijn J. L., Bevers E. M., van Dieijen G., Comfurius P., Zwaal R. F. The role of activated human platelets in prothrombin and factor X activation. Blood. 1985 Feb;65(2):319–332. [PubMed] [Google Scholar]
- Rothberger H., McGee M. P., Lee T. K. Tissue factor activity. A marker of alveolar macrophage maturation in rabbits. Effects of granulomatous pneumonitis. J Clin Invest. 1984 Jun;73(6):1524–1531. doi: 10.1172/JCI111358. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rouser G., Fkeischer S., Yamamoto A. Two dimensional then layer chromatographic separation of polar lipids and determination of phospholipids by phosphorus analysis of spots. Lipids. 1970 May;5(5):494–496. doi: 10.1007/BF02531316. [DOI] [PubMed] [Google Scholar]
- Schreiber A. B. The preclinical characterization of Monoclate factor VIII:C, antihemophilic factor (human). Semin Hematol. 1988 Apr;25(2 Suppl 1):27–32. [PubMed] [Google Scholar]
- Sinha D., Seaman F. S., Koshy A., Knight L. C., Walsh P. N. Blood coagulation factor XIa binds specifically to a site on activated human platelets distinct from that for factor XI. J Clin Invest. 1984 Jun;73(6):1550–1556. doi: 10.1172/JCI111361. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Smith R. L. Titration of activated bovine Factor X. J Biol Chem. 1973 Apr 10;248(7):2418–2423. [PubMed] [Google Scholar]
- Tracy P. B., Eide L. L., Mann K. G. Human prothrombinase complex assembly and function on isolated peripheral blood cell populations. J Biol Chem. 1985 Feb 25;260(4):2119–2124. [PubMed] [Google Scholar]
- Wood W. I., Capon D. J., Simonsen C. C., Eaton D. L., Gitschier J., Keyt B., Seeburg P. H., Smith D. H., Hollingshead P., Wion K. L. Expression of active human factor VIII from recombinant DNA clones. Nature. 1984 Nov 22;312(5992):330–337. doi: 10.1038/312330a0. [DOI] [PubMed] [Google Scholar]
- Zimmerman T. S. Purification of factor VIII by monoclonal antibody affinity chromatography. Semin Hematol. 1988 Apr;25(2 Suppl 1):25–26. [PubMed] [Google Scholar]
- van Rijn J., Rosing J., van Dieijen G. Activity of human blood platelets in prothrombin and in factor X activation induced by ionophore A23187. Eur J Biochem. 1983 Jun 1;133(1):1–10. doi: 10.1111/j.1432-1033.1983.tb07422.x. [DOI] [PubMed] [Google Scholar]