The broad objective of the proposed research is to comprehensively characterize the molecular interactions between Staphylococcus aureus and platelets as a function of the dynamic shear environment in order to provide a rational basis for the development of novel treatments to combat staphylococcal cardiovascular infections. The hypothesis to be tested is that shear stress affects the adhesive interactions between platelets and S. aureus by modulating the (i) relative importance of the adhesive molecules involved and (ii) the reaction binding kinetics. The proposed approach uses controlled, dynamic, in vitro experimental systems to systematically and comprehensively examine the importance of platelet activation, blood components, blood flow, and bacteria in the development of blood-born staphylococcal infections. A long-term goal of this work is to investigate the interrelationship between thrombogenesis and cardiovascular infection mechanisms.
The specific aims of the project are to: 1) comprehensively elucidate the molecular mechanisms of S. aureus-platelet interactions under shear conditions of direct physiological relevance; 2) characterize S. aureus-platelet heteroaggregation in cell suspensions subjected to controlled levels of shear and; 3) develop a protocol to study S. aureus-platelet aggregation in whole blood and to evaluate the effect of this extension on S. aureus-platelet interactions under shear conditions. Completion of these specific aims will provide a rational basis for the design of new therapeutic molecules to block specific adhesion events, as well as identify the most important bacterial receptors to target in vaccine development.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL066453-03
Application #
6650342
Study Section
Surgery and Bioengineering Study Section (SB)
Program Officer
Ganguly, Pankaj
Project Start
2001-09-01
Project End
2005-08-31
Budget Start
2003-09-09
Budget End
2004-08-31
Support Year
3
Fiscal Year
2003
Total Cost
$286,068
Indirect Cost
Name
University of Maryland Balt CO Campus
Department
Miscellaneous
Type
Schools of Engineering
DUNS #
061364808
City
Baltimore
State
MD
Country
United States
Zip Code
21250
Johnson, Michael A; Ross, Julia M (2008) Staphylococcal presence alters thrombus formation under physiological shear conditions in whole blood studies. Ann Biomed Eng 36:349-55
George, Niraj Procopio Evagrio; Konstantopoulos, Konstantinos; Ross, Julia Myers (2007) Differential kinetics and molecular recognition mechanisms involved in early versus late growth phase Staphylococcus aureus cell binding to platelet layers under physiological shear conditions. J Infect Dis 196:639-46
George, Niraj Procopio Evagrio; Wei, Qi; Shin, Pyong Kyun et al. (2006) Staphylococcus aureus adhesion via Spa, ClfA, and SdrCDE to immobilized platelets demonstrates shear-dependent behavior. Arterioscler Thromb Vasc Biol 26:2394-400
Nandakumar, Renu; Nandakumar, M P; Marten, Mark R et al. (2005) Proteome analysis of membrane and cell wall associated proteins from Staphylococcus aureus. J Proteome Res 4:250-7
Shin, Pyong Kyun; Pawar, Parag; Konstantopoulos, Konstantinos et al. (2005) Characteristics of new Staphylococcus aureus-RBC adhesion mechanism independent of fibrinogen and IgG under hydrodynamic shear conditions. Am J Physiol Cell Physiol 289:C727-34
Mascari, Lisa M; Ross, Julia M (2003) Quantification of staphylococcal-collagen binding interactions in whole blood by use of a confocal microscopy shear-adhesion assay. J Infect Dis 188:98-107
Hall, Andrea E; Domanski, Paul J; Patel, Pratiksha R et al. (2003) Characterization of a protective monoclonal antibody recognizing Staphylococcus aureus MSCRAMM protein clumping factor A. Infect Immun 71:6864-70