The overall objective of this proposal is to determine if there is a functional interaction between apolipo-protein (apo)E, hepatic lipase, and apoC-III in the metabolism and clearance of chylomicrons and high density lipoproteins (HDL). We will determine which of these individual proteins is rate-limiting in lipoprotein clearance and whether modulation of their interactions affects the development of atherosclerosis. The rabbit is used as the experimental model because of its sensitivity to apoE levels, its deficiency in hepatic lipase, and its exaggerated response to dietary cholesterol. Transgenic rabbits that overexpress human apoE, hepatic lipase, and apoC-III will be prepared using vectors that express these sequences at high levels in the liver or macrophage, or that permit induction in the small intestine in response to a high-fat cholesterol- supplemented atherogenic diet. The plasma lipoprotein distribution and metabolism in chow-fed and cholesterol-fed rabbits, as well as the formation of atherosclerotic lesions, will be examined. Cross-breeding experiments will allow us to determine if apoC-III can inhibit the interaction or activity of hepatic lipase, apoE, or other factors that regulate lipoprotein clearance. These experiments will test the hypothesis that apoE and hepatic lipase are rate limiting in chylomicron remnant and HDL metabolism and clearance, that apoC-III modulates apoE and hepatic lipase function, and that variations in the availability of these proteins mediate the dietary response to cholesterol, altering lipoprotein metabolism and leading to the development of atherosclerosis. These transgenic rabbits are expected to be important new models for elucidating molecular mechanisms that contribute to atherosclerosis.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
1R01HL051588-01
Application #
2228446
Study Section
Special Emphasis Panel (ZHL1-CSR-S (S1))
Project Start
1993-12-15
Project End
1997-11-30
Budget Start
1993-12-15
Budget End
1994-11-30
Support Year
1
Fiscal Year
1994
Total Cost
Indirect Cost
Name
J. David Gladstone Institutes
Department
Type
DUNS #
047120084
City
San Francisco
State
CA
Country
United States
Zip Code
94158
Rizzo, Manfredi; Taylor, John M; Barbagallo, Carlo M et al. (2004) Effects on lipoprotein subclasses of combined expression of human hepatic lipase and human apoB in transgenic rabbits. Arterioscler Thromb Vasc Biol 24:141-6
Barbagallo, C M; Fan, J; Blanche, P J et al. (1999) Overexpression of human hepatic lipase and ApoE in transgenic rabbits attenuates response to dietary cholesterol and alters lipoprotein subclass distributions. Arterioscler Thromb Vasc Biol 19:625-32
Huang, Y; Ji, Z S; Brecht, W J et al. (1999) Overexpression of apolipoprotein E3 in transgenic rabbits causes combined hyperlipidemia by stimulating hepatic VLDL production and impairing VLDL lipolysis. Arterioscler Thromb Vasc Biol 19:2952-9
Fan, J; Ji, Z S; Huang, Y et al. (1998) Increased expression of apolipoprotein E in transgenic rabbits results in reduced levels of very low density lipoproteins and an accumulation of low density lipoproteins in plasma. J Clin Invest 101:2151-64
Dichek, H L; Brecht, W; Fan, J et al. (1998) Overexpression of hepatic lipase in transgenic mice decreases apolipoprotein B-containing and high density lipoproteins. Evidence that hepatic lipase acts as a ligand for lipoprotein uptake. J Biol Chem 273:1896-903
Taylor, J M; Fan, J (1997) Transgenic rabbit models for the study of atherosclerosis. Front Biosci 2:d298-308
Sanan, D A; Fan, J; Bensadoun, A et al. (1997) Hepatic lipase is abundant on both hepatocyte and endothelial cell surfaces in the liver. J Lipid Res 38:1002-13
Fan, J; McCormick, S P; Krauss, R M et al. (1995) Overexpression of human apolipoprotein B-100 in transgenic rabbits results in increased levels of LDL and decreased levels of HDL. Arterioscler Thromb Vasc Biol 15:1889-99
Fan, J; Wang, J; Bensadoun, A et al. (1994) Overexpression of hepatic lipase in transgenic rabbits leads to a marked reduction of plasma high density lipoproteins and intermediate density lipoproteins. Proc Natl Acad Sci U S A 91:8724-8