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Secreted and intracellular phospholipases A 2 inhibition by 1‐decyl 2‐octyl‐glycerophosphocholine in rat peritoneal macrophages
Author(s) -
Boucrot P,
BobinDubigeon C,
Elkihel L,
Letourneux Y,
Jugé M,
Gandemer G,
Petit JY
Publication year - 1998
Publication title -
fundamental and clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.655
H-Index - 73
eISSN - 1472-8206
pISSN - 0767-3981
DOI - 10.1111/j.1472-8206.1998.tb00968.x
Subject(s) - extracellular , phosphocholine , arachidonic acid , phospholipase , phospholipid , intracellular , biochemistry , phospholipase a2 , eicosanoid , phospholipase a1 , phospholipase a , chemistry , phospholipase c , phosphatidylcholine , enzyme , membrane
Summary— Compounds able to inhibit phospholipases A 2 can be considered as potential anti‐inflammatory drugs. In this respect, the inhibitory effect of the phospholipid analogue 1‐decyl 2‐octyl‐rac‐glycero‐3‐phosphocholine (decyloctyl‐GPC) added to the culture medium of rat peritoneal macrophages stimulated with ionophore A23187 was determined, (a) The substrate of phospholipase A 2 1‐octadecanoyl 2‐[ 14 C]eicosatetraenoyl‐sn‐glycero‐3‐phosphocholine ([ 14 C]20:4‐GPC) was added to the culture medium. In macrophages + extracellular fluids, its hydrolysis at the 2‐position, produced [ 14 C]non‐phosphorous lipids which reached 12% of the dose at 0.14 μM, 73% at 0.9 and > 90% at 1.6 μM; in experiments where macrophages and extracellular fluids were analyzed separately, decyloctyl‐GPC initially added at 4 μM, significantly inhibited the release of [ 14 C]fatty acids and the eicosanoid synthesis, demonstrating its ability to inhibit secreted and/or intracellular phospholipases A 2 . (b) Extracellular fluids were separated from the macrophages and incubated with [ 14 C]20:4‐GPC: 48% of the dose was hydrolyzed by extracellular fluid‐associated secreted phospholipase A 2 and decyloctyl‐GPC at 3 μM, reduced this hydrolysis by 50%. (c) [ 3 H]arachidonic acid ([ 3 H]20:4) was added to the culture medium and was esterified in the macrophage membrane phospholipids. Activation of intracellular phospholipase A 2 induced the release of [ 3 H] fatty acids and eicosanoid synthesis. These releases were inhibited by 50% with decyloctyl‐GPC added at 4 μM. (d) [ 3 H]20:4 and [ 14 C]20:4‐GPC were added to the culture medium of the macrophages. [ 3 H] and [ 14 C] fatty acids and eicosanoids were released in macrophages or extracellular fluids. They were significantly reduced by the phospholipid analogue added at 4 μM. It is concluded that secreted and intracellular phospholipases A 2 were both inhibited by decyloctyl‐GPC which extensively reduced the 20:4 release from exogenous and membrane phospholipids and therefore eicosanoid synthesis.