Regulation of high density lipoprotein receptors in cultured macrophages: role of acyl-CoA:cholesterol acyltransferase
| Autor: | B Brennhausen, Gerd Schmitz, G Assmann, R Krause, R Niemann |
|---|---|
| Rok vydání: | 1985 |
| Předmět: |
Male
Apolipoprotein E Apolipoprotein B Sterol O-acyltransferase Mice Inbred Strains Receptors Cell Surface General Biochemistry Genetics and Molecular Biology Mice chemistry.chemical_compound medicine Animals Humans Binding site Molecular Biology Cells Cultured Receptors Lipoprotein General Immunology and Microbiology biology Cholesterol Macrophages General Neuroscience Monocyte RNA-Binding Proteins Metabolism Flow Cytometry Kinetics medicine.anatomical_structure chemistry Biochemistry Cell culture biology.protein lipids (amino acids peptides and proteins) Carrier Proteins Lipoproteins HDL Sterol O-Acyltransferase Research Article |
| Zdroj: | The EMBO Journal. 4:2773-2779 |
| ISSN: | 0261-4189 |
| DOI: | 10.1002/j.1460-2075.1985.tb04003.x |
| Popis: | The interaction of human serum high density lipoproteins (HDL) with mouse peritoneal macrophages and human blood monocytes was studied. Saturation curves for binding of apolipoprotein E-free [125I]HDL3 showed at least two components: non-specific binding and specific binding that saturated at approximately 40 micrograms HDL protein/ml. Scatchard analysis of specific binding of apo E-free [125I]-HDL3 to cultured macrophages yielded linear plots indicative of a single class of specific binding sites. Pretreatment of [125I]HDL3 with various apolipoprotein antibodies (anti apo A-I, anti apo A-II, anti apo C-II, anti apo C-III and anti apo E) and preincubation of the cells with anti-idiotype antibodies against apo A-I and apo A-II prior to the HDL binding studies revealed apolipoprotein A-I as the ligand involved in specific binding of HDL. Cellular cholesterol accumulation via incubation with acetylated LDL led to an increase in HDL binding sites as well as an increase in the activity of the cytoplasmic cholesterol esterifying enzyme acyl-CoA:cholesterol acyltransferase (ACAT). Incubation of the cholesterol-loaded cells in the presence of various ACAT inhibitors (Sandoz 58.035, Octimibate-Nattermann, progesterone) revealed a time- and dose-dependent amplification in HDL binding and HDL-mediated cholesterol efflux. It is concluded that the homeostasis of cellular cholesterol in macrophages is regulated in part by the number of HDL binding sites and that ACAT inhibitors enhance HDL-mediated cholesterol efflux from peripheral cells. |
| Databáze: | OpenAIRE |
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