It is well known that plasma levels of apolipoprotein (apo)A-I and high density lipoprotein (HDL) are inversely correlated with the risk of cardiovascular disease (CVD). CVDs, which include heart attacks, stroke and high blood pressure, are estimated to shorten the average American life expectancy by about 10 years. Unfortunately, the mechanisms that protect the body from the pathological accumulation of lipid and cholesterol that cause CVD are not well understood. Recent studies have indicated that the ATP binding cassette transporter (ABCA1) is a critical cell surface protein required for the transfer of cellular lipid and cholesterol to lipid-free forms of apoA-I. The interaction of apoA-I and ABCA1 is key for the formation and maintenance of HDL levels in plasma and is likely important for the first step of reverse cholesterol transport from peripheral tissues including macrophages in the vessel wall. The long-term goal of this research is to understand this interaction in molecular detail. During the first funding period, we demonstrated that the C-terminal helical domain of apoA-I plays a critical role in interactions with the cell membrane under control of ABCA1. Our working model is that apoA-I interacts with ABCA1 through a two-step pathway that involves the tethering of apoA-I helix 10 to a cell surface lipid domain generated by the lipid translocase activity of ABCA1 followed by a direct protein-to-protein interaction between the two molecules. This scheme will be tested by a) determining the regions of apoA-I and ABCA1 that make contact during the protein-protein interaction, b) determining the characteristics of regions within other exchangeable apolipoproteins that are responsible for interaction with ABCA1, and c) identifying the nature of the cell surface lipid domain that is generated by ABCA1. A highly novel approach will be used that combines cutting edge mass spectrometry techniques with chemical cross-linking chemistry to derive new structural information on the apoA-I/ABCA1 interaction. This understanding will form a basis for new interventions designed to enhance apolipoprotein-mediated cholesterol efflux from cells, particularly those within the atherosclerotic vessel wall.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL062542-07
Application #
6872991
Study Section
Metabolism Study Section (MET)
Program Officer
Applebaum-Bowden, Deborah
Project Start
1999-04-01
Project End
2009-03-31
Budget Start
2005-04-01
Budget End
2006-03-31
Support Year
7
Fiscal Year
2005
Total Cost
$268,625
Indirect Cost
Name
University of Cincinnati
Department
Pathology
Type
Schools of Medicine
DUNS #
041064767
City
Cincinnati
State
OH
Country
United States
Zip Code
45221
Gordon, Scott M; Li, Hailong; Zhu, Xiaoting et al. (2016) Impact of genetic deletion of platform apolipoproteins on the size distribution of the murine lipoproteome. J Proteomics 146:184-94
Gordon, Scott M; Li, Hailong; Zhu, Xiaoting et al. (2015) A comparison of the mouse and human lipoproteome: suitability of the mouse model for studies of human lipoproteins. J Proteome Res 14:2686-95
Heink, Anna; Davidson, W Sean; Swertfeger, Debi K et al. (2015) A Comparison of Methods To Enhance Protein Detection of Lipoproteins by Mass Spectrometry. J Proteome Res 14:2943-50
Smith, Loren E; Yang, Jun; Goodman, Leah et al. (2012) High yield expression and purification of recombinant human apolipoprotein A-II in Escherichia coli. J Lipid Res 53:1708-15
Gordon, Scott M; Hofmann, Susanna; Askew, David S et al. (2011) High density lipoprotein: it's not just about lipid transport anymore. Trends Endocrinol Metab 22:9-15
Basford, Joshua E; Wancata, Lauren; Hofmann, Susanna M et al. (2011) Hepatic deficiency of low density lipoprotein receptor-related protein-1 reduces high density lipoprotein secretion and plasma levels in mice. J Biol Chem 286:13079-87
Smith, Loren E; Davidson, W Sean (2010) The role of hydrophobic and negatively charged surface patches of lipid-free apolipoprotein A-I in lipid binding and ABCA1-mediated cholesterol efflux. Biochim Biophys Acta 1801:64-9
Tubb, Matthew R; Smith, Loren E; Davidson, W Sean (2009) Purification of recombinant apolipoproteins A-I and A-IV and efficient affinity tag cleavage by tobacco etch virus protease. J Lipid Res 50:1497-504
Sethi, Amar A; Stonik, John A; Thomas, Fairwell et al. (2008) Asymmetry in the lipid affinity of bihelical amphipathic peptides. A structural determinant for the specificity of ABCA1-dependent cholesterol efflux by peptides. J Biol Chem 283:32273-82
Mythreye, Karthikeyan; Satterwhite, Lisa L; Davidson, W Sean et al. (2008) ApoA-I induced CD31 in bone marrow-derived vascular progenitor cells increases adhesion: implications for vascular repair. Biochim Biophys Acta 1781:703-9

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