The long-term objective of this research is to prevent atherosclerosis by understanding more completely the mechanisms by which plasma low density lipoprotein (LDL) and lipoproteins rich in apolipoprotein E (apo E) are cleared from plasma and how they interact with cells. The principal routs for LDL catabolism is through tissue uptake by the LDL receptor. However, evidence from several sources suggests that other lipoprotein receptors may also be present, especially in liver. This project focuses on defining further the role of a 109 kD Hep G2 liver cell protein which binds LDL and apo E-rich postprandial lipoproteins. It has been purified by HPLC, three tryptic peptides have been microsequenced, and it has bee identified as nucleolin by both sequence data and immunological comparison with authenthic nucleolin. Nucleolin is known to shuttle between the nucleus and cytoplasm and may carry important extranuclear information for the regulation of transcription. The present proposal will test 2 hypotheses: 1. That lipoprotein binding to nucleolin regulates cholesterol metabolism. 2. That the growth-promoting properties of lipoproteins are mediated in part through nucleolin. The ability of anti-nucleolin IgG to prevent lipoprotein binding to cultured cells in addition to Hep G2 cells will be determined. Regulation of hydroxymethylglutaryl CoA reductase and acyl cholesterol acyl transferase will studied. The effect of antibody to alter lipoprotein turnover in intact animals will be established. Finally, cells lacking the LDL receptor and expressing little nucleolin will be transfected with nucleolin cDNA in order to determine what effect a primary increase in nucleolin has on lipoprotein binding and cholesterol metabolism. Conversely, the effect of lipoproteins on nucleolin expression and shuttling will be determined.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL029229-08
Application #
3340338
Study Section
Metabolism Study Section (MET)
Project Start
1986-04-01
Project End
1993-06-30
Budget Start
1991-07-01
Budget End
1992-06-30
Support Year
8
Fiscal Year
1991
Total Cost
Indirect Cost
Name
Washington University
Department
Type
Schools of Medicine
DUNS #
062761671
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Krut, L H; Schonfeld, G; Ostlund Jr, R E (1996) Microscale preparation of natural and labeled oxysterols. Lipids 31:529-34
Ostlund Jr, R E; Yang, J W; Heath-Monnig, E et al. (1994) Increased low density lipoprotein receptor expression mediated through the insulin-like growth factor-I receptor in cultured fibroblasts. Mol Endocrinol 8:904-9
Myers, P R; Wright, T F; Tanner, M A et al. (1994) The effects of native LDL and oxidized LDL on EDRF bioactivity and nitric oxide production in vascular endothelium. J Lab Clin Med 124:672-83
Seip, R L; Moulin, P; Cocke, T et al. (1993) Exercise training decreases plasma cholesteryl ester transfer protein. Arterioscler Thromb 13:1359-67
Ostlund Jr, R E (1993) A minimal model for human whole body cholesterol metabolism. Am J Physiol 265:E513-20
Ostlund Jr, R E; McGill, J B; Herskowitz, I et al. (1993) D-chiro-inositol metabolism in diabetes mellitus. Proc Natl Acad Sci U S A 90:9988-92
Ostlund Jr, R E; Matthews, D E (1993) [13C]cholesterol as a tracer for studies of cholesterol metabolism in humans. J Lipid Res 34:1825-31
Bosner, M S; Ostlund Jr, R E; Osofisan, O et al. (1993) Assessment of percent cholesterol absorption in humans with stable isotopes. J Lipid Res 34:1047-53
Levy, R; Ostlund Jr, R E; Schonfeld, G et al. (1992) Cholesteryl ester storage disease: complex molecular effects of chronic lovastatin therapy. J Lipid Res 33:1005-15
Ostlund Jr, R E; Staten, M A; Kohrt, W M et al. (1991) Insulin-like growth factor and apolipoprotein B. JAMA 266:1937-8

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