Difference in microviscosity induced by different cholesterol levels in the surface membrane lipid layer of normal lymphocytes and malignant lymphoma cells

Shinitzky, Meir; Inbar, Michael

doi:10.1016/0022-2836(74)90318-0

Cited by 618 publications

(194 citation statements)

References 20 publications

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“…With the aid of a highly sensitive and accurate technique (14-16) based on fluorescence polarization analysis of the fluorescent hydrocarbon probe 1,6-diphenyl 1,3,5-hexatriene (16) when embedded in the surface membrane lipid core of intact cells (17,18), we (19).…”

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confidence: 99%

Cholesterol as a Bioregulator in the Development and Inhibition of Leukemia

Inbar

Shinitzky

1974

Proc. Natl. Acad. Sci. U.S.A.

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115

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Leukemia in mice and humans is accompanied by a marked deficiency of unesterified cholesterol in the surface membrane of leukemic cells as compared to normal leukocytes. This deficiency induces a significant reduction in their membrane microviscosity. Since cholesterol in the cell surface membrane is exchangeable with cholesterol in the serum lipoproteins, concomitant to the cellular deficiency of cholesterol, the average level of cholesterol in the blood serum of leukemic patients is substantially below the average normal level. Based on these observations and the effect of membrane microviscosity on biological functions, a working hypothesis that describes the role of cholesterol in the development and inhibition of leukemia is suggested. This hypothesis can also account for the effect of cholesterol and membrane microviscosity on various other cellular activities of leukocytes.

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confidence: 99%

Cholesterol as a Bioregulator in the Development and Inhibition of Leukemia

Inbar

Shinitzky

1974

Proc. Natl. Acad. Sci. U.S.A.

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115

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“…Determination of rotational relaxation times or microviscosity according to steady-state techniques [46,47], were not used since the steady-state anisotropy used in these calculations is comprised of two components : r , , the limiting anisotropy, which is determined primarily by the degree to which the rotations are hindered and R , the rotational rate [45,48].…”

Section: Fluorescence Spectroscopymentioning

confidence: 99%

Sex and age alter plasma membranes of cultured fibroblasts

Schroeder

Goetz

Roberts

1984

European Journal of Biochemistry

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Human skin fibroblasts were taken from age-matched male and female subjects. The cells were then cultured under identical conditions and passage-number matched. Plasma membranes were isolated and membrane enzyme activities, lipid composition, and structure of isolated plasma membranes were measured in order to determine the presence of significant sex differences in human fibroblast membrane properties. The results indicated that plasma membranes from normal female subjects had a 1.6-fold and 3.6-fold higher cholesterol/phospholipid ratio and oleic acid (18:2) content than normal male subjects. The limiting anisotropy and the rotational relaxation time of fluorescence probe molecules such as trans-parinaric acid and 1,6-diphenyl-l,3,5-hexatriene in the plasma membranes was not significantly different from fibroblasts of male versus female normal subjects. The total activity of plasma membrane (Na', K+)-ATPase was significantly higher in female than male normal subjects. A potential 'membrane structural disorder', Huntington's disease, was confirmed in fibroblast membranes from male but not from female Huntington's disease subjects. The possibility that Huntington's disease was a 'premature membrane aging' phenomenon was considered. A comparison of plasma membrane enzymes, lipids, and structure from old and young Huntington's disease subjects did not show differences consistent with accelerated membrane aging as explaining the molecular basis for the disease. The age-dependent differences noted in aged Huntington's disease subjects: increased phosphatidylcholineiphosphatidylethanolamine ratio and sphingomyelin + lysophosphatidylcholine content of fibroblast plasma membranes were not significantly altered when compared to normal age-matched controls. However, (Na +, K+)-ATPase activity was significantly enhanced in fibroblast plasma membranes of older Huntington's disease subjects unlike those of control subjects. In conclusion, sex and age differences in membrane properties of cultured cells represent important potential variables in the elucidation of human genetic disorders that may be membrane-related.The effect of hormonal status in vitro or in vivo on structure and function of membranes is an area where our present knowledge is extremely limited not only for normal subjects but also for those affected by genetic disorders. Direct effects of prostaglandin E on erythrocyte fluidity [I] and of insulin, glucagon, and thyroid hormone on liver plasma membranes [2,3] have been demonstrated. In addition, thyroid status (hyperthyroid vs hypothyroid or euthyroid) dramatically altered the lipid composition and structure of both the verylow-density lipoproteins secreted by the perfused rat liver [4,5] and the isolated liver plasma membranes [3]. Such indirect structural alterations in membranes may be mediated by Ca2+ [3,6 -81 or via altered fatty acid composition of membrane phosphoglycerides [9 -121 and can bc accounted for, at least in part, by altered fatty acid desaturase: enzymes [I21 or altered secretion of v...

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Section: Isolation Of the Apoproteinsmentioning

confidence: 99%

“…Human plasma was drawn from normal fasting donors and the lipoprotein fractions were isolated by ultracentrifugal flotation at the appropriate densities [8]. The human apoproteins apoA-I, apoA-11, apoC-I and apoC-111 proteins were isolated, after delipidation of high-density and very-low-density lipoproteins, by ion-exchange chromatography on a DEAE-cellulose column in 6 M urea 191.…”

Section: Isolation Of the Apoproteinsmentioning

confidence: 99%

“…phospholipid complexes. Calorimetric and potentiometric titration studies on isolated complexes consisting of synthetic dimyristoyl-3-sn-phosphatidylcholine and human apoA-I, apoA-11, apoC-I, apoC-111 proteins [8,9] have indicated that both hydrophobic and hydrophilic forces are involved in the apoprotein-phospholipid interaction and that changes in the fluidity of the lipid phase might contribute to the highly negative enthalpy change recorded during the association process [lo, 111. These microviscosity measurements should lead to a better understanding of the forces responsible for the stabilization of the lipid .…”

mentioning

confidence: 99%

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Fluorescence Depolarization Studies of Fluidity and Phase Transition in Human Apoprotein · Phospholipid Complexes

Rosseneu

Vercaemst

Caster

et al. 1979

European Journal of Biochemistry

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The microviscosity of unilamellar vesicles of dimyristoyl-3-sn-phosphatidylcholine and that of phosphatidylcholine . apoprotein complexes was followed by fluorescence depolarization after labeling with 1,6-diphenyl-1,3,5-hexatriene. The transition temperature from gel-crystalline to liquidcrystalline phase is 24 "C for the dimyristoyl-phosphatidylcholine vesicles and is shifted to around 30 "C in the complexes between phosphatidylcholine and apoA-I, apoA-11, apoC-I, apoC-I11 proteins while the cooperativity of the transition is decreased. At temperatures below the transition of the phospholipid, the microviscosity of the complexes of phosphatidylcholine with apoA-I, apoA-I1 and apoC-I proteins is lower than that of the phosphatidylcholine, while the opposite effect is observed above 30 "C. The phosphatidylcholine . apoprotein complexes isolated on a Sepharose 6B column have a molecular weight around 100000 and a phosphatidylcholine/apoprotein ratio of 2-2.6 (w/w). The microviscosity measurements at 35 "C performed after elution of the column enable the complex to be detected. The size and microviscosity of the apoprotein . phosphatidylcholine complex is compatible with a model where the vesicular structure has disappeared and the amino acid side chains present hydrophobic interaction with the phosphatidylcholine acyl chains.The fluidity of a lipid bilayer is an essential parameter in the functional regulation of biological membranes as documented by various studies on natural and artificial membranes [l -31. The fluidity of lipoprotein fractions has also been investigated by measurement of their microviscosity, in an attempt to clarify the nature of the lipid-protein interactions within these plasma lipoproteins [4,5]. These data suggest that the fluidity or microviscosity of the plasma lipoproteins is dependent on their lipid composition, the hydrophobicity of the apoproteins and on the temperature IS].In previous studies we reported on the microviscosity of native and recombined lipoproteins from normal individuals and hyperlipoproteinemic patients [6,7]. The results stressed the predominant contribution of the nature and content of the lipid classes to the microviscosity of plasma lipoproteins.The aim of the present study is to assess the influence of the protein components of the plasma lipo-h'omcw/uruw. Names for lipids follow the recent recommendations of the IUPAC-IUB Committee on Biochemical Nomenclature, see Eur. J . Biochem. 79, 11 -21 (1977); phosphatidylcholine refers to 3-sn-phosphatidylcholine, previously referred to as lecithin.proteins on the organization of the lipid phase in apoprotein . phospholipid complexes. Calorimetric and potentiometric titration studies on isolated complexes consisting of synthetic dimyristoyl-3-sn-phosphatidylcholine and human apoA-I, apoA-11, apoC-I, apoC-111 proteins [8,9] have indicated that both hydrophobic and hydrophilic forces are involved in the apoprotein-phospholipid interaction and that changes in the fluidity of the lipid phase might contribute to the highly...

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Difference in microviscosity induced by different cholesterol levels in the surface membrane lipid layer of normal lymphocytes and malignant lymphoma cells

Cited by 618 publications

References 20 publications

Cholesterol as a Bioregulator in the Development and Inhibition of Leukemia

Cholesterol as a Bioregulator in the Development and Inhibition of Leukemia

Sex and age alter plasma membranes of cultured fibroblasts

Fluorescence Depolarization Studies of Fluidity and Phase Transition in Human Apoprotein · Phospholipid Complexes

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