Following a vascular injury or during inflammation, endothelial cells rapidly release the contents of their storage granules, called Weibel- Palade bodies (WPBs). The major soluble component of these granules is von Willebrand factor (vWf). vWf is a large multimeric glycoprotein that has a dual role in hemostasis: it promotes platelet adhesion and it protects factor VIII (FVIII) against proteolysis. vWf is synthesized with a prosequence which directs multimer formation through an as yet unknown mechanism. The formation of the WPBs and the function of vWf after secretion are the main topics of this proposal. We will be greatly assisted by the existence of vWf-deficient mice that we prepared during the last grant period. The proposal has four specific aims. I) Weibel-Palade body formation. We will examine whether the vWf prosequence has a disulfide isomerase enzymatic activity, which would explain its role in vWf multimerization. We will continue our studies on the molecular mechanisms involved in granulogenesis. II) Role of vWf in normal physiology. We will evaluate the effect of vWf-deficiency of FVIII half life and secretion. We will examine whether there is a feedback mechanism by which vWf or its prosequence modulates FVIII biosynthesis. We will study the role of vWf in platelet thrombus formation in vitro and in vivo using a new intravital microscopy model we have developed. The importance of vWf will be compared with that of other platelet adhesion molecules, i.e., fibrinogen and beta3 integrins. III) Role of vWf in various diseases. We will test the role of vWf in diseases in which platelets are thought to play an important part, e.g., septic shock, stroke and atherosclerosis. IV) Generation and characterization of new mutant mice. We will produce combinations of genetic defects by crossing the vWf-deficient mice with other mutant strains. We will evaluate the effect of gene dosage of vWf in homeostasis and disease by producing mice with twice the normal level of vWf. Our research will employ a variety of techniques including protein chemistry, cell culture, intravital microscopy, animal experimentation, and finally, genetic engineering of a targeted gene duplication in mice. Learning about the mechanisms involved in WPB formation and secretion is clinically relevant, as the main treatment of patients with low vWf relies on releasing the stored protein pool. An understanding of the exact roles that vWf plays in platelet adhesion and thrombus formation may lead to new anti-thrombotic therapies which could become applicable in diseases where platelet adhesion and/or aggregation is part of the disease process.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37HL041002-16
Application #
6536931
Study Section
Hematology Subcommittee 2 (HEM)
Program Officer
Link, Rebecca P
Project Start
1988-07-01
Project End
2003-06-30
Budget Start
2002-07-01
Budget End
2003-06-30
Support Year
16
Fiscal Year
2002
Total Cost
$583,118
Indirect Cost
Name
Immune Disease Institute, Inc.
Department
Type
DUNS #
115524410
City
Boston
State
MA
Country
United States
Zip Code
02115
Carbo, Carla; Yuki, Koichi; Demers, Melanie et al. (2013) Isoflurane inhibits neutrophil recruitment in the cutaneous Arthus reaction model. J Anesth 27:261-8
Crescente, Marilena; Thomas, Grace M; Demers, Melanie et al. (2012) ADAMTS13 exerts a thrombolytic effect in microcirculation. Thromb Haemost 108:527-32
Demers, Melanie; Ho-Tin-Noe, Benoit; Schatzberg, Daphne et al. (2011) Increased efficacy of breast cancer chemotherapy in thrombocytopenic mice. Cancer Res 71:1540-9
Zhao, Bing-Qiao; Chauhan, Anil K; Canault, Matthias et al. (2009) von Willebrand factor-cleaving protease ADAMTS13 reduces ischemic brain injury in experimental stroke. Blood 114:3329-34
Ho-Tin-Noe, Benoit; Goerge, Tobias; Wagner, Denisa D (2009) Platelets: guardians of tumor vasculature. Cancer Res 69:5623-6
Ho-Tin-Noe, Benoit; Carbo, Carla; Demers, Melanie et al. (2009) Innate immune cells induce hemorrhage in tumors during thrombocytopenia. Am J Pathol 175:1699-708
Bergmeier, Wolfgang; Oh-Hora, Masatsugu; McCarl, Christie-Ann et al. (2009) R93W mutation in Orai1 causes impaired calcium influx in platelets. Blood 113:675-8
Cifuni, Stephen M; Wagner, Denisa D; Bergmeier, Wolfgang (2008) CalDAG-GEFI and protein kinase C represent alternative pathways leading to activation of integrin alphaIIbbeta3 in platelets. Blood 112:1696-703
Chauhan, Anil K; Walsh, Meghan T; Zhu, Guojing et al. (2008) The combined roles of ADAMTS13 and VWF in murine models of TTP, endotoxemia, and thrombosis. Blood 111:3452-7
Chauhan, Anil K; Kisucka, Janka; Cozzi, Maria R et al. (2008) Prothrombotic effects of fibronectin isoforms containing the EDA domain. Arterioscler Thromb Vasc Biol 28:296-301

Showing the most recent 10 out of 55 publications