Interaction of atherogenic lipoproteins with cultured cells. A confocal laser scanning microscopy study.

摘要

Low density lipoprotein (LDL) and lipoprotein (a) [Lp(a)] were covalently labeled with the fluorescent dyes BODIPY succinimidyl ester (green) or Rhodamine iodoacetamide (red). The interaction of the fluorescent lipoproteins with HepG2 cells was visualized by means of a confocal laser scanning fluorescence microscope operating in the dual wavelength mode. If LDL or Lp(a) were incubated with the cells both lipoproteins bound to the cell surface at 4°C or were internalized by the cells at 37°C. In all cases larger amounts of LDL interacted with the cells compared with Lp(a). When mixtures of LDL and Lp(a), each labeled with a different dye, were incubated with cells again both lipoproteins bound to the cell surface (4°C) or were internalized by the cells (37°C). In addition the major part of the lipoproteins colocalized either on the cell surface or inside the cells. Thus, we conclude that interactions of Lp(a) with cells is mediated by LDL - probably via the LDL receptor - to a large extent.