The central hypothesis to be examined in this proposal is that SR-B1 must be associated with caveolae to promote selective cholesterol ester uptake and free cholesterol efflux from macrophages.
Aim 1 : To determine the extent to which SR-131 requires caveolae to facilitate cholesterol ester uptake and cholesterol efflux in macrophages. We have established cell lines that express only SR-131 or SR-BI and caveolin. Therefore, we can study the ability of SR-131 to mediated uptake and efflux of lipid in the presence or absence of caveolae. We will confirm our findings in human primary monocyte-derived macrophages.
Aim 2 : To determine the extent to which oxidized lipoproteins alter caveola structure and inhibit SR BI-dependent cholesterol flux in macrophages. This will be accomplished by assessing i) the effects of oxidized lipoproteins on the lipid composition of caveolae, ii) the effects of oxidized lipoproteins on the structure of caveolae, iii) the influence of caveolae modifications on the subcellular localization of SR-131, and iv) the effects of oxidized lipoproteins on SR-131 activity.
Aim 3 : To determine the effect of macrophage-specific over-expression of SR-B1 and caveolin on the development of atherosclerotic lesions in transgenic mice. This will be investigated by using transgenic mice over-expressing SR-131, caveolin, or both in macrophages by means of the macrosialin promoter. The mice will be crossbred to the atherosclerosis susceptible apoE -/- strain and the extent of atherosclerosis quantified by the size of the lesion and by the cholesterol/cholesterol ester content of the lesions.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
1R01HL064056-01
Application #
6038676
Study Section
Pathology A Study Section (PTHA)
Project Start
2000-02-01
Project End
2003-12-31
Budget Start
2000-02-01
Budget End
2000-12-31
Support Year
1
Fiscal Year
2000
Total Cost
$304,373
Indirect Cost
Name
University of Kentucky
Department
Physiology
Type
Schools of Medicine
DUNS #
832127323
City
Lexington
State
KY
Country
United States
Zip Code
40506
Li, Xiang-An; Guo, Ling; Dressman, James L et al. (2005) A novel ligand-independent apoptotic pathway induced by scavenger receptor class B, type I and suppressed by endothelial nitric-oxide synthase and high density lipoprotein. J Biol Chem 280:19087-96
Li, Xiang-An; Everson, William V; Smart, Eric J (2005) Caveolae, lipid rafts, and vascular disease. Trends Cardiovasc Med 15:92-6
Zhu, Weifei; Smart, Eric J (2005) Myristic acid stimulates endothelial nitric-oxide synthase in a CD36- and an AMP kinase-dependent manner. J Biol Chem 280:29543-50
Chikani, Gentle; Zhu, Weifei; Smart, Eric J (2004) Lipids: potential regulators of nitric oxide generation. Am J Physiol Endocrinol Metab 287:E386-9
Smart, Eric J; De Rose, Robert A; Farber, Steven A (2004) Annexin 2-caveolin 1 complex is a target of ezetimibe and regulates intestinal cholesterol transport. Proc Natl Acad Sci U S A 101:3450-5
Zhu, Weifei; Smart, Eric J (2003) Caveolae, estrogen and nitric oxide. Trends Endocrinol Metab 14:114-7
Dressman, James; Kincer, Jeanie; Matveev, Sergey V et al. (2003) HIV protease inhibitors promote atherosclerotic lesion formation independent of dyslipidemia by increasing CD36-dependent cholesteryl ester accumulation in macrophages. J Clin Invest 111:389-97
Gong, Ming; Wilson, Melinda; Kelly, Thomas et al. (2003) HDL-associated estradiol stimulates endothelial NO synthase and vasodilation in an SR-BI-dependent manner. J Clin Invest 111:1579-87
Matveev, Sergey V; Smart, Eric J (2002) Heterologous desensitization of EGF receptors and PDGF receptors by sequestration in caveolae. Am J Physiol Cell Physiol 282:C935-46
Li, Xiang-An; Titlow, William B; Jackson, Brian A et al. (2002) High density lipoprotein binding to scavenger receptor, Class B, type I activates endothelial nitric-oxide synthase in a ceramide-dependent manner. J Biol Chem 277:11058-63

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