Biomaterial Database

Uptake by macrophages of low-density lipoprotein damaged by nitrogen dioxide in air. 1995

K Kikugawa, and M Beppu, and Y Okamoto

Tokyo College of Pharmacy, Japan.

In order to know whether nitrogen dioxide, an environmental and endogenous free radical toxin, can participate in the formation of atherosclerotic lesions, damage to low-density lipoprotein (LDL) by nitrogen dioxide and uptake of the damaged LDL by macrophages were investigated. A solution of LDL at pH 7.5 was exposed to an atmosphere of nitrogen dioxide (70 ppm) in air at 37 degrees C for 5 or 10 h. Lipid oxidation was induced by the exposure as assessed by the formation of thiobarbituric acid reactive substances. Apolipoprotein B was covalently cross-linked via nondisulfide bonds. Fluorescence analysis showed that tryptophan residues were extensively decreased, and amino acid analysis indicated that the contents of histidine, lysine, and tyrosine residues were decreased by 30-40, 10-20, and 20-30%, respectively. Binding of LDL to thioglycolate-induced mouse peritoneal macrophages was markedly increased by the exposure as observed by the binding of mouse erythrocytes coated with LDL. The activity of LDL to convert macrophages into lipid-laden foam cells was also increased by the exposure. Modification of lysine residues of apo B with lipid oxidation products formed by the exposure may be responsible for the uptake by macrophages. The results suggest the possibility that exposure of LDL in vivo to nitrogen dioxide participates in the formation of atherosclerotic lesions.

UI	MeSH Term	Description	Entries
D008077	Lipoproteins, LDL	A class of lipoproteins of small size (18-25 nm) and light (1.019-1.063 g/ml) particles with a core composed mainly of CHOLESTEROL ESTERS and smaller amounts of TRIGLYCERIDES. The surface monolayer consists mostly of PHOSPHOLIPIDS, a single copy of APOLIPOPROTEIN B-100, and free cholesterol molecules. The main LDL function is to transport cholesterol and cholesterol esters to extrahepatic tissues.	Low-Density Lipoprotein,Low-Density Lipoproteins,beta-Lipoprotein,beta-Lipoproteins,LDL(1),LDL(2),LDL-1,LDL-2,LDL1,LDL2,Low-Density Lipoprotein 1,Low-Density Lipoprotein 2,LDL Lipoproteins,Lipoprotein, Low-Density,Lipoproteins, Low-Density,Low Density Lipoprotein,Low Density Lipoprotein 1,Low Density Lipoprotein 2,Low Density Lipoproteins,beta Lipoprotein,beta Lipoproteins
D009585	Nitrogen Dioxide	Nitrogen oxide (NO2). A highly poisonous gas. Exposure produces inflammation of lungs that may only cause slight pain or pass unnoticed, but resulting edema several days later may cause death. (From Merck, 11th ed) It is a major atmospheric pollutant that is able to absorb UV light that does not reach the earth's surface.	Nitrogen Peroxide,Dioxide, Nitrogen,Peroxide, Nitrogen
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D002448	Cell Adhesion	Adherence of cells to surfaces or to other cells.	Adhesion, Cell,Adhesions, Cell,Cell Adhesions
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000393	Air Pollutants	Any substance in the air which could, if present in high enough concentration, harm humans, animals, vegetation or materials. Substances include GASES; PARTICULATE MATTER; and volatile ORGANIC CHEMICALS.	Air Pollutant,Air Pollutants, Environmental,Environmental Air Pollutants,Environmental Pollutants, Air,Air Environmental Pollutants,Pollutant, Air,Pollutants, Air,Pollutants, Air Environmental,Pollutants, Environmental Air
D017737	Macrophages, Peritoneal	Mononuclear phagocytes derived from bone marrow precursors but resident in the peritoneum.	Peritoneal Macrophages,Macrophage, Peritoneal,Peritoneal Macrophage
D066298	In Vitro Techniques	Methods to study reactions or processes taking place in an artificial environment outside the living organism.	In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In