Effects of Chronic Ethanol Consumption on Sterol Transfer Proteins in Mouse Brain |
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Authors: | Sean C. Myers-Payne,Robert N. Fontaine,Amy Loeffler,Lixia Pu,&dagger &Dagger A. M. Rao,A. B. Kier,&dagger &Dagger W. Gibson Wood, Friedhelm Schroeder |
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Affiliation: | Departments of Physiology and Pharmacology and; Pathobiology, Texas A&M University, Texas Veterinary Medical Center, College Station, Texas;; Geriatric Research, Education and Clinical Center, V.A. Medical Center;and; Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota, U.S.A. |
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Abstract: | Abstract: Although lipids are essential to brain function, almost nothing is known of lipid transfer proteins in the brain. Early reports indicates cross-reactivity of brain proteins with antisera against two native liver sterol transfer proteins, sterol carrier protein-2 (SCP-2) and the liver form of fatty acid-binding protein (L-FABP). Herein, polyclonal antibodies raised against the recombinant liver sterol transfer proteins SCP-2 and L-FABP were used to identify the lipid transfer proteins in the brains of alcohol-treated and control mice. L-FABP was not detectable in brain of either control or chronic ethanol-treated mice. In contrast, SCP-2 not only was present, but its level was significantly ( p < 0.05) increased 23 and 50%, respectively, in brain homogenates and synaptosomes of mice exposed to alcohol. To determine whether antibodies against the recombinant liver SCP-2 reflected true levels of SCP-2 in brain, the cDNA sequence for brain SCP-2 was isolated from a brain cDNA library. The mouse brain SCP-2 sequence was 99.99% identical to the mouse liver SCP-2 sequence. The translated sequence differed by only one amino acid, and the replacement was conservative. Thus, unlike the fatty acid binding proteins, the SCP-2 moieties of brain and liver are essentially identical. Polyclonal antibodies against acyl-CoA binding protein, a lipid-binding protein that does not bind or transfer sterol, showed that increased levels of brain SCP-2 with chronic ethanol consumption did not represent a general increase in content of all lipid transfer proteins. Changes in the amount of SCP-2 may contribute to membrane tolerance to ethanol. |
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Keywords: | Brain Sterol carrier protein-2 cDNA Sequence Alcohol |
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