Biomaterial Database

Expression of heterologous human apolipoprotein E by J774 macrophages enhances cholesterol efflux to HDL3. 1994

T Mazzone, and C Reardon

Department of Medicine, Rush Medical College, Chicago, IL 60612.

Expression of apolipoprotein (apo) E by macrophages is tightly regulated by cellular cholesterol content. We have investigated a potential modulating role for apoE on macrophage cholesterol homeostasis by stably transfecting the J774 macrophage, which does not express its endogenous apoE gene, with a human apoE cDNA expression vector and comparing cholesterol homeostasis in this cell line with that of a control line transfected with the neomycin resistance construct only. Incubation in serum-free medium after cholesterol loading produced no difference in cellular cholesterol content between apoE secreting and non-secreting J774 cells. Similarly, in serum-free medium there was no difference in the amount of radiolabeled cholesterol effluxed. Addition of cAMP or S58035 to cholesterol-loaded J774 cells did enhance efflux of radiolabeled cholesterol from apoE secreting compared to non-secreting macrophages but did not detectably alter cellular free cholesterol or cholesteryl ester mass. Incubation with HDL3 alone, however, significantly decreased macrophage cholesteryl ester mass compared to a 24-h incubation in serum-free medium from 10.5 +/- 3.9 to 3.2 +/- 2.0 (P < 0.01) in apoE-secreting J774 cells. During a 24-h incubation in HDL3, cholesteryl ester fell from 6.4 +/- 2.4 to 0.8 +/- 0.7 (delta = 5.6 micrograms/mg) in apoE-secreting cells and from 9.3 +/- 2.2 to 7.7 +/- micrograms/mg (delta = 1.6 micrograms/mg) in non-secreting cells (P < 0.005 apoE-secreting vs. non-secreting cells).(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D008075	Lipoproteins, HDL	A class of lipoproteins of small size (4-13 nm) and dense (greater than 1.063 g/ml) particles. HDL lipoproteins, synthesized in the liver without a lipid core, accumulate cholesterol esters from peripheral tissues and transport them to the liver for re-utilization or elimination from the body (the reverse cholesterol transport). Their major protein component is APOLIPOPROTEIN A-I. HDL also shuttle APOLIPOPROTEINS C and APOLIPOPROTEINS E to and from triglyceride-rich lipoproteins during their catabolism. HDL plasma level has been inversely correlated with the risk of cardiovascular diseases.	High Density Lipoprotein,High-Density Lipoprotein,High-Density Lipoproteins,alpha-Lipoprotein,alpha-Lipoproteins,Heavy Lipoproteins,alpha-1 Lipoprotein,Density Lipoprotein, High,HDL Lipoproteins,High Density Lipoproteins,Lipoprotein, High Density,Lipoprotein, High-Density,Lipoproteins, Heavy,Lipoproteins, High-Density,alpha Lipoprotein,alpha Lipoproteins
D008264	Macrophages	The relatively long-lived phagocytic cell of mammalian tissues that are derived from blood MONOCYTES. Main types are PERITONEAL MACROPHAGES; ALVEOLAR MACROPHAGES; HISTIOCYTES; KUPFFER CELLS of the liver; and OSTEOCLASTS. They may further differentiate within chronic inflammatory lesions to EPITHELIOID CELLS or may fuse to form FOREIGN BODY GIANT CELLS or LANGHANS GIANT CELLS. (from The Dictionary of Cell Biology, Lackie and Dow, 3rd ed.)	Bone Marrow-Derived Macrophages,Monocyte-Derived Macrophages,Macrophage,Macrophages, Monocyte-Derived,Bone Marrow Derived Macrophages,Bone Marrow-Derived Macrophage,Macrophage, Bone Marrow-Derived,Macrophage, Monocyte-Derived,Macrophages, Bone Marrow-Derived,Macrophages, Monocyte Derived,Monocyte Derived Macrophages,Monocyte-Derived Macrophage
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D002784	Cholesterol	The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.	Epicholesterol
D002788	Cholesterol Esters	Fatty acid esters of cholesterol which constitute about two-thirds of the cholesterol in the plasma. The accumulation of cholesterol esters in the arterial intima is a characteristic feature of atherosclerosis.	Cholesterol Ester,Cholesteryl Ester,Cholesteryl Esters,Ester, Cholesterol,Ester, Cholesteryl,Esters, Cholesterol,Esters, Cholesteryl
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001057	Apolipoproteins E	A class of protein components which can be found in several lipoproteins including HIGH-DENSITY LIPOPROTEINS; VERY-LOW-DENSITY LIPOPROTEINS; and CHYLOMICRONS. Synthesized in most organs, Apo E is important in the global transport of lipids and cholesterol throughout the body. Apo E is also a ligand for LDL receptors (RECEPTORS, LDL) that mediates the binding, internalization, and catabolism of lipoprotein particles in cells. There are several allelic isoforms (such as E2, E3, and E4). Deficiency or defects in Apo E are causes of HYPERLIPOPROTEINEMIA TYPE III.	Apo-E,Apo E,Apo E Isoproteins,ApoE,Apolipoprotein E Isoproteins,Apoprotein (E),Apoproteins E,Isoproteins, Apo E,Isoproteins, Apolipoprotein E
D018014	Gene Transfer Techniques	The introduction of functional (usually cloned) GENES into cells. A variety of techniques and naturally occurring processes are used for the gene transfer such as cell hybridization, LIPOSOMES or microcell-mediated gene transfer, ELECTROPORATION, chromosome-mediated gene transfer, TRANSFECTION, and GENETIC TRANSDUCTION. Gene transfer may result in genetically transformed cells and individual organisms.	Gene Delivery Systems,Gene Transfer Technique,Transgenesis,Delivery System, Gene,Delivery Systems, Gene,Gene Delivery System,Technique, Gene Transfer,Techniques, Gene Transfer,Transfer Technique, Gene,Transfer Techniques, Gene
D018076	DNA, Complementary	Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.	Complementary DNA,cDNA,cDNA Probes,Probes, cDNA