Biopolym. Cell. 1989; 5(2):74-78.
Cell Biology
Cholesterol effect on Apolipoprotein B secretion and binding of low-density lipoproteins hepatoma HepG2 Cells
1Fuki I. V., 1Preobrazhensky S. N., 1Misharin A. Yu., 1Bushmakina N. G., 1Menshchikov G. B., 1Repin V. S.
- Research Institute of Experimental Cardiology, National Cardiological Research Centre, Academy of Medical Sciences of the USSR
Moscow, USSR
Abstract
The effect of cholesterol, oleic acid and recombinant complexes containing apolipoprotein Al/dimyristoylphosphatidylcholine (apoAl/DMPC) on apolipoprotein B (apoB) secretion and uptake of 125I-labeled low-density lipoproteins (LDL) by cultured human hepatoma HepG2 cells was studied. Addition of different concentrations of exogenous cholesterol (as ethanol solution) to the cells increased apoB secretion and inhibited 1 25I-labelled LDL uptake in a dose-dependent manner. Similar effects were found when the cells were incubated with different concentrations of oleic acid, which enhanced the intracellular cholesterol content. The presence of complexes apoAl/DMPC in the culture medium, which decreased the cellular pool of cholesterol, resulted in the opposite effects: apoB secretion was inhibited, while the LDL-receptor activity was stimulated. Significant negative correlation (r = —0.92, p<0.001) was found between apoB secretion and LDL uptake. The obtained data suggest that cholesterol can induce cooperated changes in apoB secretion and LDL-rcceptor activity.
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