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Principal Investigator: JAY W HEINECKE
Organization: VANDERBILT UNIVERSITY MEDICAL CENTER
Fiscal Year: 2019
Award: $262,515
Funding agency: National Heart Lung and Blood Institute
We propose to investigate the structural basis of the interaction of LCAT with HDL. We will complement these
in vitro studies with analyses of HDLs of subjects with LCAT deficiency. Because these patients have very low
HDL-C levels but apparently little increased cardiovascular risk, their HDL might provide important insights
about HDL functions that are cardioprotective but do not involve HDL-C. We have three specific aims.
First, based on the crystal structures of apoA-I and apoA-IV, we will introduce specific point mutations into
apoA-I to determine their impact on its binding sites and activation of cholesteryl ester synthesis by LCAT. In
parallel studies, we will use chemical cross-linking together with high-resolution mass spectrometry to identify
the precise sites of interaction of LCAT with apoA-I in reconstituted HDLs. Using these data, we will test
structural models of HDL established with reconstituted and native HDLs by Segrest and Davidson.
Second, we use a method we recently developed, termed calibrated ion mobility analysis, to quantify the
concentration and size of HDL species in the blood of control and LCAT deficient subjects. We hypothesize
that normal or higher levels of certain HDL subspecies are sufficient for cardioprotection in LCAT-deficient
humans, even in the absence of other forms of HDL.
Third, using macrophages, we will assess the sterol efflux capacity of HDLs from LCAT-deficient and control
subjects. Efflux by ABCA1 and ABCG1 will also be quantified, using genetically engineered cell lines. We will
use both serum HDL (serum depleted of apoB-containing lipoproteins), isolated HDL, and reconstituted
discoidal and spherical HDL particles for our studies We hypothesize that the very small HDL subspecies
present at normal levels in LCAT deficient subjects is a potent mediator of sterol efflux and HDL-mediated
cardioprotection.
Terms: <3-Pyridinecarboxylic Acid><ABC Transport Protein><ABC Transporter Protein><ABC Transporters><ABCA1><ABCA1 protein><ATP binding cassette transporter 1><ATP-Binding Cassette Transporters><Abscission><Apo A-1><Apo A-I><Apo A1><Apo AI><Apo-A><Apo-B><ApoA><ApoA-1><ApoA-I><ApoB><Apolipoprotein A-1><Apolipoprotein A-I><Apolipoprotein A1><Apolipoprotein AI><Apolipoproteins A><Apolipoproteins B><Atheroscleroses><Atherosclerosis><Atherosclerotic Cardiovascular Disease><Binding Sites><Biological Function><Biological Process><Blood><Blood Plasma><Blood Reticuloendothelial System><Blood Serum><CETP><CETP gene><Cardiovascular Diseases><Cell Line><Cell Surface Proteins><Cell membrane><CellLine><Chemicals><Cholesterol><Cholesterol Ester Lysolecithin Acyltransferase><Cholesterol Esters><Cholesteryl Esters><Choline Glycerophospholipids><Choline Phosphoglycerides><Clinical Research><Clinical Study><Collaborations><Combining Site><Complement><Complement Proteins><Crystallization><Cytoplasmic Membrane><Data><Enzyme Gene><Enzymes><Epidemiologic Research><Epidemiologic Studies><Epidemiological Studies><Epidemiology Research><Excision><Extirpation><Family><Genetic study><Goals><HDL><HDL Cholesterol><HDL Cholesterol Lipoproteins><HDL Lipoproteins><HDL lecithin lipoprotein><HDLDT1><Heavy Lipoproteins><High Density Lipoprotein Cholesterol><High Density Lipoproteins><High density lipoprotein><Human><Hydrophobicity><In Vitro><LCAT><Lecithin><Lecithin Acyltransferase><Lecithin Cholesterol Acyltransferase><Left><Lipid Transfer Protein I><Lipids><Lipoproteins><Mass Photometry/Spectrum Analysis><Mass Spectrometry><Mass Spectroscopy><Mass Spectrum><Mass Spectrum Analyses><Mass Spectrum Analysis><Measures><Mediating><Mediator><Mediator of Activation><Mediator of activation protein><Methods><Modeling><Modern Man><Molecular><Niacin><Nicotinic Acids><Patients><Phosophatidylcholine-Sterol Acyltransferase><Phosphatides><Phosphatidylcholine-Sterol O-Acyltransferase><Phosphatidylcholines><Phospholipids><Plasma><Plasma Cholesteryl Ester Transfer Protein><Plasma Membrane><Plasma Serum><Point Mutation><Population><Process><Property><Proteins><Reactive Site><Removal><Resolution><Reticuloendothelial System, Serum, Plasma><Roentgen Rays><Serum><Site><Sterols><Strains Cell Lines><Structural Models><Structure><Surgical Removal><Testing><Therapeutic><X-Radiation><X-Rays><X-Rays Radiation><Xrays><alpha-Lipoprotein Cholesterol><alpha-Lipoproteins><atheromatosis><atherosclerosis risk><atherosclerotic disease><atherosclerotic risk><atherosclerotic vascular disease><base><cardioprotectant><cardioprotection><cardioprotective><cardiovascular disease risk><cardiovascular disorder><cardiovascular disorder risk><cardiovascular risk><cardiovascular risk factor><cholesterol-efflux regulatory protein><cross-link><crosslink><cultured cell line><epidemiologic investigation><epidemiology study><genetically engineered cells><genetically modified cells><high density lipoprotein phosphatidylcholine><inhibitor><inhibitor/antagonist><insight><interdisciplinary approach><interest><ion mobility><lecithin HDL><lecithin cholesterol acyltransferase deficiency><macrophage><multidisciplinary approach><nano particle><nano-sized particle><nanoparticle><nanosized particle><particle><phosphatidylcholine HDL><phosphatidylcholine sterol acyltransferase><phospholipid cholesterol acyltransferase><plasmalemma><reconstitute><reconstitution><resection>