The long term objective of this study is to enhance understanding of the mechanisms regulating tissue factor (TF)-dependent blood coagulation on cell surfaces. A human ovarian carcinoma cell line constitutively expressing cell surface tissue factor will be used for these studies and biochemical reactions will be carried out in purified systems. In addition as indicated other cell lines will also be used as positive and negative controls. Four major questions will be examined.
The first aim i s to determine whether earlier results that factor VII bound to reconstituted purified TF is preferentially and rapidly activated by trace concentrations of factors Xa and IXa will also hold for factor VII bound to cell surface TF. Additionally, the effect of trace concentrations of other proteases, e.g., factor Xlla and thrombin will be examined. The information obtained from this study may provide clues in understanding why infused factor VIla is effective In controlling the bleeding in hemophiliacs and for an apparent Increased susceptibility to venous thrombosis of patients with factor VII deficiency.
The second aim i s to examine the importance of asymmetric distribution of negatively charged phospholipids on cell surfaces as a modulator of TF functional expression on cell surfaces. In these experiments various chemical and physiological stimuli will be used to alter the membrane. Annexin V, a protein that binds to negatively charged phospholipids in vesicles and on cell surfaces will be used as a probe to monitor the changes in expression of anionic phospholipid on the cell surface.
The third aim i s to probe the nature of factor Xa and factor Xa/tissue factor pathway inhibitor (TFPI) complex interaction with cell surfaces.
The final aim i s to test whether binding of TFPI alone or factor XA/TFPI complex to cell surface factor VIIA/TF leads to internalization of the inhibited complex. In the above proposed studies various biochemical techniques will be employed such as radioligand binding, activation peptide release from tritiated factors IX and X, immunolabelling, SDS-PAGE analysis, and electron microscopy.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
7R01HL042813-05
Application #
3361122
Study Section
Hematology Subcommittee 2 (HEM)
Project Start
1993-08-15
Project End
1995-06-30
Budget Start
1993-08-15
Budget End
1994-06-30
Support Year
5
Fiscal Year
1993
Total Cost
Indirect Cost
Name
University of Texas Health Center at Tyler
Department
Type
Other Domestic Higher Education
DUNS #
City
Tyler
State
TX
Country
United States
Zip Code
75708
Rao, L V; Pendurthi, U R (1998) Tissue factor on cells. Blood Coagul Fibrinolysis 9 Suppl 1:S27-35
Idell, S; Pendurthi, U; Pueblitz, S et al. (1998) Tissue factor pathway inhibitor in tetracycline-induced pleuritis in rabbits. Thromb Haemost 79:649-55
Pendurthi, U R; Williams, J T; Rao, L V (1997) Inhibition of tissue factor gene activation in cultured endothelial cells by curcumin. Suppression of activation of transcription factors Egr-1, AP-1, and NF-kappa B. Arterioscler Thromb Vasc Biol 17:3406-13
Sorensen, B B; Persson, E; Freskgard, P O et al. (1997) Incorporation of an active site inhibitor in factor VIIa alters the affinity for tissue factor. J Biol Chem 272:11863-8
Pendurthi, U R; Williams, J T; Rao, L V (1997) Acidic and basic fibroblast growth factors suppress transcriptional activation of tissue factor and other inflammatory genes in endothelial cells. Arterioscler Thromb Vasc Biol 17:940-6
Rao, L V; Rapaport, S I (1996) Cells and the activation of factor VII. Haemostasis 26 Suppl 1:1-5
Sevinsky, J R; Rao, L V; Ruf, W (1996) Ligand-induced protease receptor translocation into caveolae: a mechanism for regulating cell surface proteolysis of the tissue factor-dependent coagulation pathway. J Cell Biol 133:293-304
Rao, L V; Williams, T; Rapaport, S I (1996) Studies of the activation of factor VII bound to tissue factor. Blood 87:3738-48
Rao, L V; Hoang, A D; Rapaport, S I (1996) Mechanism and effects of the binding of lupus anticoagulant IgG and prothrombin to surface phospholipid. Blood 88:4173-82
Zivelin, A; Rao, L V; Rapaport, S I (1995) Evidence for an essential role of tissue factor dependent blood coagulation in the pathogenesis of the local Shwartzman reaction. Blood Cells Mol Dis 21:9-19

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