Relationship of oxidant-mediated cytotoxicity to phospholipid metabolism in endothelial cells
- Veterans Administration Medical Center, Minneapolis, MN (USA)
Exposure to oxidants permeabilizes cell membranes and liberates unesterified fatty acids (UFA) in a variety of cell types, including endothelial cells. Products of phospholipase activity, particularly UFA and lysophosphatides, possess potent detergent-like properties, and we postulated that oxidant injury might be mediated by the accumulation of these toxic phospholipase products. Several radiolabels were incorporated into defined positions in the phospholipids of cultured, confluent bovine pulmonary endothelial cells (BPAEC). The release of radiolabeled fatty acids and the accumulation of cell-associated phospholipase products were measured and compared to a standard cytotoxicity assay ({sup 51}Cr release) in response to an oxidant stress, in this case 0.1 to 10 mM hydrogen peroxide (H{sub 2}O{sub 2}). H{sub 2}O{sub 2} caused time- and dose-dependent {sup 51}Cr release as well as liberation of saturated (({sup 14}C)stearic acid) and unsaturated (({sup 3}H)arachidonic acid) fatty acids and the accumulation of phospholipase A2 and C products. The ability of BPAEC to incorporate UFA into complex phospholipids was shown to be severely impaired in the presence of H{sub 2}O{sub 2}. Further studies showed that H{sub 2}O{sub 2} caused depletion of BPAEC adenosine triphosphate (ATP) content to undetectable levels, and that the depletion of cellular ATP by iodoacetic acid induced substantial release of ({sup 3}H)arachidonic acid but not ({sup 14}C)stearic acid from BPAEC. This finding suggests that release of UFA in response to an oxidant stress may be due in part to a defect in ATP-dependent reacylation pathways and need not reflect any increase in phospholipase activities. Also unsaturated fatty acids were found to be toxic to BPAEC upon adding them to supernatants of cultured monolayers.
- OSTI ID:
- 5735087
- Journal Information:
- American Journal of Respiratory Cell and Molecular Biology; (USA), Vol. 4:5; ISSN 1044-1549
- Country of Publication:
- United States
- Language:
- English
Similar Records
IL-1. alpha. increases arachidonyl-CoA: Lysophospholipid acyltransterase activity and stimulates ( sup 3 H) arachidonate incorporation into phospholipids in rat mesangial cells
Effects of arachidonic acid and 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine on prolactin secretion from anterior pituitary cells
Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ARACHIDONIC ACID
SECRETION
HYDROGEN PEROXIDE
BIOLOGICAL EFFECTS
LIPASES
ENZYME ACTIVITY
PHOSPHOLIPIDS
METABOLISM
ATP
CARBON 14 COMPOUNDS
CATTLE
CHROMIUM 51
DOSE-RESPONSE RELATIONSHIPS
ENDOTHELIUM
TIME DEPENDENCE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BODY
CARBON COMPOUNDS
CARBOXYLESTERASES
CARBOXYLIC ACIDS
CHROMIUM ISOTOPES
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
ELECTRON CAPTURE RADIOISOTOPES
ENZYMES
ESTERASES
ESTERS
EVEN-ODD NUCLEI
HYDROGEN COMPOUNDS
HYDROLASES
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LIPIDS
MAMMALS
MONOCARBOXYLIC ACIDS
NUCLEI
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXYGEN COMPOUNDS
PEROXIDES
RADIOISOTOPES
RUMINANTS
TISSUES
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology
550501 - Metabolism- Tracer Techniques