Receptor-mediated endocytosis of low-density lipoprotein by cultured human glomerular cells.
Lipoproteins might be involved in the pathogenesis of glomerular damage. Uptake of low-density lipoprotein (LDL) by cultured human glomerular cells has been studied using LDL, labelled with the fluorescent probe 1,1'-dioctadecyl-3,3,3'3'-tetramethyl-indocarbocyanine perchlorate (diI). Cells have been characterised using phase-contrast microscopy, monoclonal antibodies and lectins. Differentiated glomerular epithelial cells, epithelial-like cells and mesangial cells all took up diI-LDL. Uptake was specific for LDL, of high affinity and inhibited by excess unlabelled LDL, heparin and preloading the cells with cholesterol. Binding of diI-LDL to the cell surface was restricted to discrete areas which were arranged in linear arrays on mesangial cells. Endocytosis of surface-bound diI-LDL occurred within 3 min and breakdown of internalised diI-LDL within 30 min. These results indicate that cultured human glomerular cells take up LDL by receptor-mediated endocytosis.
Rayner
H C
HC
Department of Nephrology, Leicester General Hospital, UK.
Horsburgh
T
T
Brown
S L
SL
Lavender
F L
FL
Winder
A F
AF
Walls
J
J
D002478:Cells, Cultured; D004705:Endocytosis; D004848:Epithelium / Q000378:metabolism; D006801:Humans; D007678:Kidney Glomerulus / Q000378:metabolism*; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism; D011973:Receptors, LDL / Q000502:physiology*
D008077:Lipoproteins, LDL; D011973:Receptors, LDL