The long-term aim of the proposed project is to define the structure-function relationships of apoB and its role in atherogenesis by studying naturally-occurring human variants of apoB detected by immunochemical and sizing procedures. Plasmas of hypo- and non-familial hypercholesterolemic individuals identified by screening in """"""""walk-in"""""""" clinics and in the Lipid clinic, and of unselected patients undergoing coronary angiography will be tested. Competitive radioimmunoassays and 3-6% polyacrylamide gradient SDS gel electrophoresis and Western blotting using a panel of monoclonal antiapob antibodies directed against the major regions of apoB-100 will be used to identify size- or immunogenetic variants of aPoB. To ascertain the patterns of inheritance of any variants, families of affected individuals also will be similarly tested. Special structural and functionality studies will be performed in probands, selected members of their kindreds, and appropriate control subjects. The special study protocols are meant to characterize the physicochemical and immunochemical properties of lipoproteins and the interactions of LDLs containing normal end variant apoBs with fibroblast LDL receptor, mouse macrophage scavenger receptors, and heparin. The responses of subjects to a fat meal containing vitamin A and to 6 days of a minimal fat diet will be assessed in order to judge the ability of intestine and liver to produce lipoproteins and to attempt {o deduce the tissue source of the variant apoB. Kinetic studies using 15N-glycine and GC-mass spectrometry will be carried out to assess whether altered levels of variants ere due to atherogenesis or catabolism of apoB. Finally, molecular studies on the protein and gene level will be performed to characterize molecular defects. This comprehensive study should provide information on the structure-function relationship of apoB and relate features of apoB structure to the atherogenecity (or lack thereof) of apoB-containing lipoproteins.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL042460-05
Application #
3360692
Study Section
Nutrition Study Section (NTN)
Project Start
1989-04-01
Project End
1994-03-31
Budget Start
1993-04-01
Budget End
1994-03-31
Support Year
5
Fiscal Year
1993
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
Wu, J; Kim, J; Li, Q et al. (1999) Known mutations of apoB account for only a small minority of hypobetalipoproteinemia. J Lipid Res 40:955-9
Srivastava, R A; Toth, L; Srivastava, N et al. (1999) Regulation of the apolipoprotein B in heterozygous hypobetalipoproteinemic knock-out mice expressing truncated apoB, B81. Low production and enhanced clearance of apoB cause low levels of apoB. Mol Cell Biochem 202:37-46
Chen, Z; Saffitz, J E; Latour, M A et al. (1999) Truncated apo B-70.5-containing lipoproteins bind to megalin but not the LDL receptor. J Clin Invest 103:1419-30
Elias, N; Patterson, B W; Schonfeld, G (1999) Decreased production rates of VLDL triglycerides and ApoB-100 in subjects heterozygous for familial hypobetalipoproteinemia. Arterioscler Thromb Vasc Biol 19:2714-21
Srivastava, R A; Srivastava, N; Averna, M et al. (1999) Molecular bases of low production rates of apolipoprotein B-100 and truncated apoB-82 in a mutant HepG2 cell line generated by targeted modification of the apolipoprotein B gene. J Lipid Res 40:901-12
Aguilar-Salinas, C A; Barrett, H; Schonfeld, G (1998) Metabolic modes of action of the statins in the hyperlipoproteinemias. Atherosclerosis 141:203-7
Pulai, J I; Latour, M A; Kwok, P Y et al. (1998) Diabetes mellitus in a new kindred with familial hypobetalipoproteinemia and an apolipoprotein B truncation (apoB-55). Atherosclerosis 136:289-95
Pulai, J I; Neuman, R J; Groenewegen, A W et al. (1998) Genetic heterogeneity in familial hypobetalipoproteinemia: linkage and non-linkage to the apoB gene in Caucasian families. Am J Med Genet 76:79-86
Pulai, J I; Zakeri, H; Kwok, P Y et al. (1998) Donor splice mutation (665 + 1 G_T) in familial hypobetalipoproteinemia with no detectable apoB truncation. Am J Med Genet 80:218-20
Zhu, X F; Noto, D; Seip, R et al. (1997) Organ loci of catabolism of short truncations of apoB. Arterioscler Thromb Vasc Biol 17:1032-8

Showing the most recent 10 out of 41 publications