Liposome uptake by cultured macrophages mediated by modified low-density lipoproteins.
We have investigated effects of native low-density lipoproteins (LDL) and malondialdehyde-treated LDL on the interaction of 5(6)-carboxyfluorescein-labeled liposomes bearing antibodies to LDL with cultured J774 macrophages. It was found that an addition of modified LDL to the incubation medium resulted in 15-20-fold increase of carboxyfluorescein binding to cells, whereas native LDL did not produce such effect. The increase of carboxyfluorescein binding to macrophages in the presence of modified LDL was not due to an enhanced leakage of the label from liposomes. The modified-LDL-mediated binding of carboxyfluorescein to cells was reduced to 20-30% of the initial level in the presence of cell-respiration inhibitors (NaF and antimycin A). Fluorescent microscopy data also indicate the modified-LDL-induced incorporation of liposome contents into cells. The results obtained in this study make it possible to assume that in the presence of malondialdehyde-treated LDL, liposomes with antibodies to LDL may be incorporated into macrophages via the receptor-mediated pathway for modified LDL.
D000906:Antibodies / Q000008:administration & dosage; D000968:Antimycin A / Q000494:pharmacology; D002478:Cells, Cultured; D005452:Fluoresceins; D006801:Humans; D008077:Lipoproteins, LDL / Q000276:immunology / Q000378:metabolism*; D008081:Liposomes / Q000008:administration & dosage; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D008315:Malondialdehyde; D014677:Pharmaceutical Vehicles; D011973:Receptors, LDL / Q000378:metabolism; D012969:Sodium Fluoride / Q000494:pharmacology
D000906:Antibodies; D005452:Fluoresceins; D008077:Lipoproteins, LDL; D008081:Liposomes; D014677:Pharmaceutical Vehicles; D011973:Receptors, LDL; C024098:6-carboxyfluorescein; D008315:Malondialdehyde; D000968:Antimycin A; D012969:Sodium Fluoride