In this application we propose to continue efforts aimed at elucidating von Willebrand factor (VWF) structure and function focusing on four aims.
In aim 1 we will test whether structural elements in the VWF A1 domain (VWFA1) can differentially regulate specific adhesive properties. Preliminary data indicate that the interaction of glycoprotein (GP) Iba with VWFA1 immobilized onto a surface, leading to platelet adhesion, may occur through different mechanisms as compared to binding of soluble VWF mediating platelet aggregation. Our goal is to define the distinctive structural elements underlying the initiation and regulation of specific VWF activities and establish their functional relevance in models of vascular injury.
In aim 2 we intend to ascertain whether a-thrombin can act as a physiologic modulator of VWF adhesive properties. We hypothesize that VWFA1 and a-thrombin establish inter-molecular contacts when bound to the same GPIba receptor, and this may influence the stability of the VWFA1-GPIba bond independently of shear stress. We propose to identify the VWFA1 residues that support the interaction with a-thrombin bound to GPIba, thus defining a novel mechanism for the regulation of VWF function during thrombogenesis.
In aim 3 we propose to evaluate whether a specific IgG found in the human population is a modulator of VWF activity. We have identified in human and mouse blood a specific IgG that binds selectively to VWFA1, and obtained preliminary evidence that this IgG may play a role in thrombus formation. Our goal is to characterize the structure of the specific IgG, define the mode of interaction with VWFA1 and obtain definitive in vivo evidence for its physiopathological significance.
In aim 4 we will define the signaling function of collagen-bound VWF leading to platelet activation. We have characterized distinct intracytoplasmic Ca++ signals that follow platelet adhesion to immobilized VWFA1 or collagen under flow conditions, and found that they are enhanced when platelets interact with collagen-bound VWF. We propose to dissect the mechanisms of platelet activation supported by the collagen-VWF complex and the effects of hydrodynamic force on the process. The results of this research will improve our ability to influence disease processes that involve platelets in atherothrombosis.

Public Health Relevance

Experimental and clinical evidence points to a key role of VWF in thrombus formation, orchestrated by interactions with other proteins and modulated through forces generated by flowing blood. Uderstanding these different functions requires addressing structural details as well as verification of concepts in intravidal models. This wll lead to a better diagnosis and treatment for cardio- and cerebro-vascular diseases.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Program Projects (P01)
Project #
5P01HL078784-09
Application #
8476253
Study Section
Heart, Lung, and Blood Initial Review Group (HLBP)
Project Start
Project End
Budget Start
2013-05-01
Budget End
2014-04-30
Support Year
9
Fiscal Year
2013
Total Cost
$553,890
Indirect Cost
$71,062
Name
University of California San Diego
Department
Type
DUNS #
804355790
City
La Jolla
State
CA
Country
United States
Zip Code
92093
Bajaj, Jeevisha; Konuma, Takaaki; Lytle, Nikki K et al. (2016) CD98-Mediated Adhesive Signaling Enables the Establishment and Propagation of Acute Myelogenous Leukemia. Cancer Cell 30:792-805
Schmidt, Thomas; Ye, Feng; Situ, Alan J et al. (2016) A Conserved Ectodomain-Transmembrane Domain Linker Motif Tunes the Allosteric Regulation of Cell Surface Receptors. J Biol Chem 291:17536-46
Fan, Zhichao; McArdle, Sara; Marki, Alex et al. (2016) Neutrophil recruitment limited by high-affinity bent β2 integrin binding ligand in cis. Nat Commun 7:12658
Fan, Zhichao; Liu, Wei (2016) Keep Eyes on Integrins. J Immunobiol 1:
Block, Helena; Stadtmann, Anika; Riad, Daniel et al. (2016) Gnb isoforms control a signaling pathway comprising Rac1, Plcβ2, and Plcβ3 leading to LFA-1 activation and neutrophil arrest in vivo. Blood 127:314-24
Ley, Klaus; Rivera-Nieves, Jesus; Sandborn, William J et al. (2016) Integrin-based therapeutics: biological basis, clinical use and new drugs. Nat Rev Drug Discov 15:173-83
Marki, Alex; Gutierrez, Edgar; Mikulski, Zbigniew et al. (2016) Microfluidics-based side view flow chamber reveals tether-to-sling transition in rolling neutrophils. Sci Rep 6:28870
Fan, Zhichao; Ley, Klaus (2016) Leukocyte Adhesion Deficiency IV. Monocyte Integrin Activation Deficiency in Cystic Fibrosis. Am J Respir Crit Care Med 193:1075-7
Wurtzel, Jeremy G T; Lee, Seunghyung; Singhal, Sharad S et al. (2015) RLIP76 regulates Arf6-dependent cell spreading and migration by linking ARNO with activated R-Ras at recycling endosomes. Biochem Biophys Res Commun 467:785-91
Lagarrigue, Frederic; Vikas Anekal, Praju; Lee, Ho-Sup et al. (2015) A RIAM/lamellipodin-talin-integrin complex forms the tip of sticky fingers that guide cell migration. Nat Commun 6:8492

Showing the most recent 10 out of 98 publications