Receptor-mediated uptake of remnant lipoproteins by cholesterol-loaded human monocyte-macrophages
Normal human monocyte-macrophages were cholesterol-loaded, and the rates of uptake and degradation of several lipoproteins were measured and compared to rates in control cells. Receptor activities for SVI-rabbit beta-very low density lipoproteins (beta-VLDL), SVI-human low density lipoprotein, and SVI-human chylomicrons were down-regulated in cholesterol-loaded cells; however, the rate of uptake and degradation of SVI-human chylomicron remnants was unchanged from control cells. Cholesterol-loaded alveolar macrophages from a Watanabe heritable hyperlipidemic rabbit, which lack low density lipoprotein receptors, showed receptor down-regulation for SVI-beta-VLDL but not for SVI-human chylomicron remnants. In addition to chylomicron remnants, apo-E-phospholipid complexes competed for SVI-chylomicron remnant uptake, but apo-A-I-phospholipid complexes did not. Chylomicron remnants and beta-VLDL were equally effective in competing for SVI-beta-VLDL and SVI-chylomicron remnant uptake in cholesterol-loaded macrophages. The authors conclude: 1) specific lipoprotein receptor activity persists in cholesterol-loaded cells; 2) this receptor activity recognizes lipo-proteins (at least in part) by their apo-E content; and 3) cholesteryl ester accumulation can occur in monocyte-macrophages incubated with chylomicron remnants.
- Research Organization:
- Univ. of California, Los Angeles
- OSTI ID:
- 6084416
- Journal Information:
- J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 15; ISSN JBCHA
- Country of Publication:
- United States
- Language:
- English
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62 RADIOLOGY AND NUCLEAR MEDICINE
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CHOLESTEROL
CHYLOMICRONS
CONNECTIVE TISSUE CELLS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LEUKOCYTES
LIPIDS
LIPOPROTEINS
MACROPHAGES
MAMMALS
MATERIALS
MONOCYTES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PHAGOCYTES
PROTEINS
RABBITS
RADIOASSAY
RADIOISOTOPES
RECEPTORS
SOMATIC CELLS
STEROIDS
STEROLS
TRACER TECHNIQUES
UPTAKE
VERTEBRATES