Thermal behavior of human plasma high density lipoprotein

Tall, Alan R.; Deckelbaum, R.J.; Small, Donald; Shipley, G. Graham

doi:10.1016/0005-2760(77)90051-0

Cited by 68 publications

(38 citation statements)

References 14 publications

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“…LDL of M. fascicularis displayed a reversible thermal transition of their cholesterol esters from a smecticlike to a more disordered state, resembling a similar transition identified previously in human and swine LDL and swine HDLC (11,14). The evidence that the thermal transition in LDL is a result of such a structural transition of its cholesterol esters is based on analogy with the melting behavior of purified cholesterol esters and on the presence below the transition of a maximum at 1/36 A-, in the X-ray scattering profile of LDL that arises from a layered arrangement of core cholesterol esters (11,12,14,15). In the present study, the temperature of the cholesterol-ester transition of LDL was found to correlate with LPL molecular weight, (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Recent studies, with techniques such as differential scanning calorimetry and low-angle X-ray scattering, have helped to elucidate lipid structure and lipid/ protein interactions in the plasma lipoproteins (9)(10)(11)(12)(13)(14)(15). Human plasma LDL displays a broad, reversible thermal transition which encompasses body temperature associated with the transition of its core-located cholesterol esters from a smectic-like (layered) to a more disordered state (11,15).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Studies on the Structure of Low Density Lipoproteins Isolated from Macaca Fascicularis Fed an Atherogenic Diet

Tall¹,

Small²,

Atkinson³

et al. 1978

J. Clin. Invest.

133

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A B S T R A C T Cynomolgus monkeys, Macaca fascicularis, fed cholesterol-containing saturated-fat diets develop increased levels of high molecular weight plasma low density lipoproteins (LDL), associated with accelerated atherosclerosis. To study the composition and structure of these abnormal particles, LDL from monkeys, fed atherogenic and control diets, were characterized chemically and examined by differential scanning calorimetry and low-angle X-ray scattering. LDL from animals on the experimental diet showed an increase in molecular weight (4.0 to 7.0 x 106, experimental diet compared with 3.0 to 3.7 x 106, control diet) associated with a large increase in cholesterol ester content and concomitant smaller increases in protein, phospholipid, and free cholesterol. There was a strong positive correlation between molecular weight and the number of saturated and monounsaturated cholesterol esters in the particle. In contrast, particle content of polyunsaturated cholesterol esters remained constant despite large changes in total particle cholesterol esters.When examined by calorimetry and X-ray scattering, LDL from monkeys on both diets diplayed a reversible transition of cholesterol esters from an ordered smeticlike (layered) structure to a more disordered state. For all animals on the experimental diet, the peak temperature of the cholesterol-ester transition (42-48°C) was above body temperature (39°C), but below body temperature on the control diet (34-38.5°C). In the experimental group, the transition temperature was correlated with the LDL molecular weight. However, after thermal disruption of LDL, liquid-crystalline 1354 transitions of LDL cholesterol esters were observed in the same temperature range as in the intact lipoprotein, which shows that changes in particle size had little effect on the cholesterol-ester transition temperature. Rather, the transition temperature was determined by the degree of saturation of the LDL cholesterol ester fatty acids and the LDL cholesterol ester: triglyceride ratio, both of which correlated with increased LDL molecular weight. The existence of smectic-like cholesterol ester in LDL at body temperature was clearly a discriminating feature between monkeys on control and experimental diets. Diet-induced changes in the lipid composition of precursor lipoproteins of LDL appeared to lead to the existence of smectic-like cholesterol ester in LDL above body temperature. The altered composition and structure of the core lipids of high molecular weight LDL probably account, in part, for the previously documented correlation between increased LDL molecular weight and atherosclerosis in this species.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Studies on the Structure of Low Density Lipoproteins Isolated from Macaca Fascicularis Fed an Atherogenic Diet

Tall¹,

Small²,

Atkinson³

et al. 1978

J. Clin. Invest.

133

View full text Add to dashboard Cite

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“…Control and ABCA1-expressing cells were grown in 3 × 100 mm dishes until they reached 95% confl uence and then transfected with empty vector (pcDNA3), apoM-WT, or apoM-C-FLAG for 24 h. The transfection media were then removed and cells were incubated with 10 g/ml of 125 I-apoA-I (10 5 cpm/ g) for 24 h. Immediately prior to incubation, 125 I-apoA-I was heated to 60°C (i.e., just above the transition temperature of apoA-I) ( 32,33 ) for 30 min and then cooled to room temperature to standardize the conformational state of apoA-I. After incubation, the conditioned media were harvested and concentrated using an Amicon Ultra-10 concentrator and fractionated on three Superdex-200HR fast-protein liquid chromatography (FPLC) columns (Amersham Biosciences) connected in series using 0.15 M NaCl and 0.01% EDTA, pH 7.4 (column buffer).…”

Section: Nascent Pre ␤ Hdl Analysis and Isolation By Size-exclusion Cmentioning

confidence: 99%

Apolipoprotein M expression increases the size of nascent preβ HDL formed by ATP binding cassette transporter A1

Mulya¹,

Seo

Brown

et al. 2010

Journal of Lipid Research

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This article is available online at http://www.jlr.org Supplementary key words high density lipoprotein biogenesis • high density lipoprotein size • protein secretionThe inverse relationship between plasma HDL cholesterol concentration and the risk of developing premature atherosclerotic vascular disease has generated interest in understanding the role of HDL-associated apolipoproteins on the atheroprotective function of HDL ( 1-4 ). The presence of apolipoproteins on HDL plays a major role in the structural organization and intravascular metabolism of HDL, particularly with regard to cellular receptor and transporter binding, lipolytic enzyme activity, and lipid exchange or transfer. Human HDL contains two major apolipoproteins, apolipoprotein A-I (apoA-I) and apoA-II, which represent ‫ف‬ 80% and ‫ف‬ 20% of the total protein content of HDL particles, respectively ( 5, 6 ). In addition, human HDL also contains several other minor apolipoproteins, including apoA-IV ( 7, 8 ), the C-apolipoproteins ( 9, 10 ), apoD ( 11 ), apoE ( 12 ), apoJ ( 13 ), and apoL ( 14 ).Pre ␤ HDL is a descriptive term to differentiate HDLs on the basis of electrophoretic mobility in agarose gels ( 15 ). In normolipidemic human plasma, 90-95% of total HDL is ␣ -migrating HDL, and only 5-10% is pre ␤ HDL ( 16, 17 ). Pre ␤ HDLs in human plasma exist as several subpopulations of discrete sizes ( 18 ). The formation of pre ␤ HDL is thought to be important for reverse cholesterol transport (RCT), a process by which excess cholesterol in peripheral tissues is transported to the liver for secretion into bile and elimination from the body in feces. Pre ␤ HDLs have been suggested to be the initial acceptors of excess Abstract Apolipoprotein M (apoM) is a novel apolipoprotein that is reportedly necessary for pre ␤ HDL formation; however, its detailed function remains unknown. We investigated the biogenesis and properties of apoM and its effects on the initial steps of nascent pre ␤ HDL assembly by ABCA1 in HEK293 cells. Transiently transfected apoM was localized primarily in the endomembrane compartment. Pulsechase analyses demonstrated that apoM is ineffi ciently secreted, relative to human serum albumin, and that ‫ف‬ 50% remains membrane-associated after extraction with sodium carbonate, pH 11.5. To investigate the role of apoM in nascent pre ␤ HDL formation, ABCA1-expressing or control cells, transfected with empty vector, apoM, or C-terminal epitope-tagged apoM (apoM-C-FLAG), were incubated with 125 I-apoA-I for 24 h. Conditioned media were harvested and fractionated by fast-protein liquid chromatography (FPLC) to monitor HDL particle size. Pre ␤ HDL particles were formed effectively in the absence of apoM expression; however, increased apoM expression stimulated the formation of larger-sized nascent pre ␤ HDLs. Immunoprecipitation with anti-apoA-I antibody followed by apoM Western blot analysis revealed that little secreted apoM was physically associated with pre ␤ HDL. Our results suggest that apoM is an atypical secretory protein that is not ...

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“…2b), and a single transition of peak temperature 31°C in patient C. The total enthalpy of these liquid crystalline transitions of cholesterol ester of heat denatured xanthomata was 1.18+0.10 cal/g cholesterol ester which was significantly greater (P < 0.01) than that of intact xanthoma. Xanthoma kept for 1 mo at -20°C showed an initial endotherm of peak temperature -38°C (patient B) and enthalpy 7 cal/g cholesterol ester, which indicates that the cholesterol ester had crystallized (12). When recooled, liquid crystal transitions were observed which were similar to those of the native xanthoma.…”

Section: Resultsmentioning

confidence: 87%

“…Recently, the physical state of lipids in atherosclerotic tissue (7)(8)(9), in the spleen from a patient with Tangier disease (10), and in the plasma lipoproteins (11)(12)(13) has been investigated with techniques such as polarized light microscopy, scanning calorimetry, and X-ray diffraction. These procedures permit fresh, whole tissue to be examined, and give information about the structure and interactions of lipid under physiological conditions.…”

Section: Introductionmentioning

confidence: 99%

Interaction of collagen with the lipids of tendon xanthomata.

Tall¹,

Small²,

Lees³

1978

J. Clin. Invest.

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A B S T R A C T To determine the physical state of lipids in tendon xanthomata, six specimens surgically removed from three patients with familial hypercholesterolemia were studied by microscopy, calorimetry, and X-ray diffraction. The major constituents of the xanthomata were lipid (33% ofdry weight) and collagen (24% of dry weight). 836Fibers dissected from xanthomata were examined by X-ray diffraction at temperatures below and above the cholesterol ester transition. At 20°C there was a weakly oriented equatorial reflection of Bragg spacing 36A, which corresponded to the smectic phase of cholesterol ester, and a series of oriented collagen reflections. At 42°C the cholesterol ester reflection disappeared. Stretched fibers examined at 10°C showed good orientation of collagen and cholesterol ester reflections and, in addition, meridional spacings which indicated oriented crystallization of cholesterol ester. These studies suggest that a major component of tendon xanthomata is extracellular cholesterol ester which displays altered melting and molecular orientation as a result of an interaction with collagen. At xanthoma temperatures, the cholesterol ester is in a smectic liquid crystalline state, probably layered between collagen fibrils, with the long axis of the cholesterol ester molecules perpendicular to the axis of the collagen fiber. Such collagen-cholesterol ester interactions may favor the extracellular deposition of cholesterol ester derived either from intracellular sources or directly from plasma lipoproteins.

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Thermal behavior of human plasma high density lipoprotein

Cited by 68 publications

References 14 publications

Studies on the Structure of Low Density Lipoproteins Isolated from Macaca Fascicularis Fed an Atherogenic Diet

Studies on the Structure of Low Density Lipoproteins Isolated from Macaca Fascicularis Fed an Atherogenic Diet

Apolipoprotein M expression increases the size of nascent preβ HDL formed by ATP binding cassette transporter A1

Interaction of collagen with the lipids of tendon xanthomata.

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