Thrombin is a crucial regulating enzyme in the coagulation cascade and plays a critical role in cellular activation and chemotaxis, as well as being involved in inflammation, tissue repair and neural cell viability. Thrombin's effects on cells are mediated by the thrombin receptor, which evokes second messenger signaling through G-protein coupling and protein phosphorylation. To determine the biological functions of thrombin and the thrombin receptor in vivo, gene targeting will be used to create genetic deficiencies of these proteins in embryonic stem (ES) cells and mice. These models will be used to study the biological roles of thrombin and thrombin receptor in terms of hemostasis and hematopoiesis. The effects of prothrombin- and thrombin receptor-deficiencies on cell proliferation and differentiation will be studied directly in double knockout ES cells and knockout mice. If mice lacking prothrombin or the thrombin receptor are not viable, double knockout ES cells will be used to prepare chimeric mice to determine specifically which tissues can tolerate deficiencies in these proteins. Immunohistochemistry, together with in situ RNA hybridization, will be used to characterize the expressions of prothrombin and the thrombin receptor in normal or chimeric mice during development. Thrombin receptor deficient ES cell lines and tissues from deficient mice will be studied to determine whether additional protease activated receptors can be identified. These studies pursue a direct approach to define the biological functions of prothrombin and the thrombin receptor in growth, development and hemostasis.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
5F32HL009500-02
Application #
2392568
Study Section
Hematology Subcommittee 2 (HEM)
Project Start
1997-04-01
Project End
Budget Start
1997-04-01
Budget End
1998-03-31
Support Year
2
Fiscal Year
1997
Total Cost
Indirect Cost
Name
Barnes-Jewish Hospital
Department
Type
DUNS #
City
Saint Louis
State
MO
Country
United States
Zip Code
63110
Xue, J; Wu, Q; Westfield, L A et al. (1998) Incomplete embryonic lethality and fatal neonatal hemorrhage caused by prothrombin deficiency in mice. Proc Natl Acad Sci U S A 95:7603-7