Biomechanical properties of endothelial cells (ECs) are crucially important in regulation of EC mechanotransduction, cell-cell interactions, secretion of vasoactive agents, and vascular remodeling. Our recent studies have shown that EC biomechanical properties are significantly altered by changes in cellular cholesterol suggesting that EC mechanics is impaired under dyslipidemic conditions. The long-term goal of this project is to elucidate the mechanisms responsible for impairment of EC mechanics by dyslipidemia and to determine the impact of these effects on EC function. Our preliminary studies show that oxidized LDL strongly increases EC stiffness supporting the hypothesis that dyslipidemia is important for regulation of EC mechanics. In this study, we propose: (1) To determine the impact of dyslipidemic conditions on mechanical properties of arterial ECs in vitro and ex vivo. First, we will focus on determining the effects of oxLDL and its components on human ECs derived from different arterial beds. Thereafter, we will compare mechanical properties of ECs freshly-isolated from the arteries of normal and hypercholesterolemic pigs. A combination of three biophysical approaches: micropipette aspiration, atomic force and traction force microscopy will be used for comprehensive analysis of EC mechanics. We will further elucidate the relationship between EC mechanics, cytoskeleton organization and cellular cholesterol level using a combination of 3D imaging and lipid biochemistry. (2) To investigate molecular mechanisms responsible for dyslipidemia-induced changes in EC biomechanics. Specifically, we will first determine whether mechanical properties of membrane- cytoskeleton complex depend on the physical properties of the membrane lipid bilayer and/or on the integrity of cholesterol-rich membrane domains and caveolae. Next, we will test the hypothesis that Rho-GTPases and/or PI(4,5)P3, major regulators of membrane-cytoskeleton interactions, are responsible for cholesterol- induced changes in EC mechanics. (3) To elucidate the interplay between dyslipidemia and flow in the regulation of EC mechanics and cytoskeleton remodeling. In this part of the study, we will first investigate the relationship between dyslipidemia and hemodynamic conditions in regulating EC mechanical properties. Finally, we will extend these studies to determine the impact of dyslipidemia on flow-induced cytoskeleton remodeling and NO production.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL083298-05
Application #
8111691
Study Section
Vascular Cell and Molecular Biology Study Section (VCMB)
Program Officer
Fleg, Jerome
Project Start
2007-09-04
Project End
2012-06-30
Budget Start
2011-07-01
Budget End
2012-06-30
Support Year
5
Fiscal Year
2011
Total Cost
$384,077
Indirect Cost
Name
University of Illinois at Chicago
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
098987217
City
Chicago
State
IL
Country
United States
Zip Code
60612
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Rosenhouse-Dantsker, Avia; Noskov, Sergei; Durdagi, Serdar et al. (2013) Identification of novel cholesterol-binding regions in Kir2 channels. J Biol Chem 288:31154-64
Gundavaram, Madhu S; Shentu, Tzu Pin; Kowalsky, Gregory B et al. (2013) Oxidized low-density lipoprotein alters the effect of matrix stiffness on the formation of endothelial networks and capillary lumens. Pulm Circ 3:622-31

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