Sialic-acid content of low-density lipoproteins controls their binding and uptake by cultured cells.
The (high-affinity receptor)-mediated uptake of homologous low-density (low-rho) lipoproteins by cultured human arterial smooth muscle cells or human skin fibroblasts is controlled by the sialic acid content of low-rho lipoprotein particles. This conclusion is derived from the following results. 1. Gangliosides incubated with native low-rho lipoproteins associate with low-rho lipoprotein particles. Low-rho lipoproteins modified by associated GLac1, GGtet1, and GGtet2b + GGtet3 gangliosides are internalized by arterial smooth muscle cells at a rate up to 80% lower than native low-rho lipoproteins or those preincubated with desialized gangliosides. 2. The inhibitory effect of gangliosides is specific for high affinity uptake and not detectable on skin fibroblasts deficient in low-rho-lipoprotein receptor. 3. Desialyzed low-rho lipoproteins are internalized by smooth muscle cells up to 100% faster than native low-rho lipoproteins, the enhancement of uptake corresponding to the degree of desialization.
D001011:Aorta / Q000378:metabolism; D001692:Biological Transport; D002478:Cells, Cultured; D005347:Fibroblasts / Q000378:metabolism; D005732:Gangliosides / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008077:Lipoproteins, LDL / Q000378:metabolism*; D009130:Muscle, Smooth / Q000378:metabolism; D011485:Protein Binding; D012794:Sialic Acids / Q000502:physiology*; D012867:Skin / Q000378:metabolism
D005732:Gangliosides; D008077:Lipoproteins, LDL; D012794:Sialic Acids