Binding and uptake of native and modified low-density lipoproteins by human hepatocytes in primary culture.
The binding and uptake of native low-density lipoproteins and malondialdehyde-treated low density lipoproteins by human hepatocytes in primary culture has been analyzed. Experiments with 125I-labeled malondialdehyde-treated low-density lipoproteins showed that cultured liver cells took up and degraded malondialdehyde-treated low-density lipoproteins, but the cell type(s) responsible for this action remain unclear. Immunofluorescent visualization of receptor-bound low-density lipoproteins revealed that low-density lipoprotein binding sites were distributed on the surface of nearly all cells of the culture. Binding sites for malondialdehyde-treated low-density lipoproteins were found in only 5% of the cultured cells, and these cells differed from hepatocytes in shape and size. Cultured hepatocytes internalized and native low-density lipoproteins, but not malondialdehyde-treated low-density lipoproteins, labeled with the fluorescent dye 3',3'-dioctadecylindocarbocyanine. About 15% of the cells that take up 3',3'-dioctadecylindocarbocyanine-labeled malondialdehyde-treated low-density lipoproteins could be identified as liver endothelial cells and macrophages, since they internalized formaldehyde-treated human albumin and fluorescent carboxylated microspheres. Our results indicate that human hepatocytes in primary culture express surface receptors for native low-density lipoproteins but not for modified low-density lipoproteins.
Babaev
V R
VR
Institute of Experimental Cardiology, U.S.S.R. Cardiology Research Center, Academy of Medical Sciences, Moscow.
Kosykh
V A
VA
Tsibulsky
V P
VP
Ivanov
V O
VO
Repin
V S
VS
Smirnov
V N
VN
D002478:Cells, Cultured; D002675:Child, Preschool; D005455:Fluorescent Antibody Technique; D006801:Humans; D007223:Infant; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008315:Malondialdehyde / Q000494:pharmacology
D008077:Lipoproteins, LDL; D008315:Malondialdehyde