Cholesterol uptake by human glioma cells via receptor-mediated endocytosis of low-density lipoprotein

Journal of Neurosurgery
M MurakamiY Morino

Abstract

Low-density lipoprotein (LDL) is a carrier of the cholesterol found in human plasma. Cells utilize cholesterol for membrane synthesis by taking up LDL via receptor-mediated endocytosis. In the present study, interactions of LDL with human malignant glioma cell lines (U-251 MG and KMG-5) were investigated biochemically and morphologically. The LDL, labeled with the fluorescent dyes 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine (DiI) and fluorescein isothiocyanate (FITC), was internalized by both cell processes and cell bodies. Reductive methylation of DiI-labeled LDL, which abolishes the ability of the cell to bind to the LDL receptor, prevented the internalization of the cholesterol moiety of LDL. Cellular binding of 125I-LDL to U-251 MG cells at 4 degrees C revealed the presence of a specific saturable-associated receptor (dissociation constant (Kd) approximately 38 micrograms/ml). Endocytic uptake of 125I-LDL or 3H-cholesterol oleate-labeled LDL (3H-LDL) at 37 degrees C demonstrated the cell-associated 125I-LDL and 3H-LDL increase. The intracellular degradation of protein moiety increased linearly with time. Reductive methylation of 3H-LDL led to a remarkable decrease in the cell-associated cholesterol moiety of LDL....Continue Reading

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Citations

Jun 1, 1992·Journal of Neuroscience Research·E S Krul, J Tang
Aug 6, 2002·Bioorganic & Medicinal Chemistry Letters·Bingqing JiD Robert Lu
Aug 16, 2003·Epilepsia·Bernhard Schaller, Stephan J Rüegg
Dec 1, 1995·Journal of Gastroenterology·M NotarnicolaA Di Leo
May 1, 2011·NMR in Biomedicine·Kamaiah JayalakshmiNeeraj Sinha

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Methods Mentioned

BETA
fluorescence microscopy

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