calcimycin and linoleic-acid-hydroperoxide

To approach the mechanism of the stimulating effect of linoleic acid hydroperoxide on the production of matrix metalloproteinases (MMPs) in human aortic intimal smooth muscle cells (ISMC), we investigated the effect of the hydroperoxide on the cytosolic level of Ca2+. Linoleic acid hydroperoxide provoked an increase in the cytosolic Ca2+ level, but it had no effect on the level of inositol phosphates (IPs) in these cells, in contrast with the effect of platelet-derived growth factor (PDGF), which elevated the level of both Ca2+ and IPs in these cells. A23187, a calcium ionophore, stimulated ISMC to produce matrix prometalloproteinase 1. These results indicate that linoleic acid hydroperoxide stimulates the production of MMPs in ISMC by elevation of the cytosolic Ca2+ level without the intervention of IPs. In addition, we found that the hydroperoxide has no effect on the binding of PDGF to its specific receptor on ISMC.

Topics: Aorta, Thoracic; Becaplermin; Calcimycin; Calcium; Cells, Cultured; Collagenases; Endothelium, Vascular; Enzyme Precursors; Humans; Immunoblotting; Inositol Phosphates; Kinetics; Linoleic Acids; Lipid Peroxides; Matrix Metalloproteinase 1; Muscle, Smooth, Vascular; Platelet-Derived Growth Factor; Proto-Oncogene Proteins c-sis; Tunica Intima

The ability of nordihydroguaiaretic acid (NDGA) to inhibit arachidonic acid (AA) release from rat alveolar macrophages treated with t-butyl hydroperoxide (tBOOH) or from Chinese hamster lung fibroblasts (V79 cells) treated with linoleic acid hydroperoxide (LOOH) was examined. Treatment of alveolar macrophages with 100 microM tBOOH significantly increased arachidonic acid release and its conversion to metabolites. Pretreatment of macrophages with NDGA (greater than or equal to 2.5 microM) inhibited the release of AA and its subsequent metabolism following addition of tBOOH. Treatment of V79 cells with 1 microM LOOH stimulated the release of AA. Pretreatment with either 1 or 10 microM NDGA prior to the addition of LOOH inhibited the release of AA. A23187 (2 microM)-stimulated release of AA from V79 cells was less sensitive to NDGA inhibition. Pretreatment with 10 microM NDGA, but not with 1 microM NDGA, inhibited A23187-stimulated release of AA. PLA2-dependent hydrolysis of micelle preparations of disaturated phosphatidylcholine was not inhibited by NDGA. Previous studies have suggested that the addition of peroxides alters cells by inducing lipid peroxidation so that the action of phospholipases upon their membranes is enhanced. The results suggest that NDGA, a lipid-soluble antioxidant which traps free radicals, indirectly blocked the action of phospholipases upon cell membranes by inhibiting lipid peroxidation.

Topics: Animals; Antioxidants; Arachidonic Acids; Calcimycin; Catechols; Cell Line; Chromatography, High Pressure Liquid; Cricetinae; Cricetulus; Egtazic Acid; In Vitro Techniques; Linoleic Acids; Lipid Peroxides; Macrophages; Male; Masoprocol; Peroxides; Phospholipases A; Phospholipases A2; Pulmonary Alveoli; Quinacrine; Rats; Rats, Inbred Strains; tert-Butylhydroperoxide