In Vivo Activity of a Phospholipase C Inhibitor, 1-(6-((17β-3-Methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122), in Acute and Chronic Inflammatory Reactions

• Published in: The Journal of pharmacology and experimental therapeutics 2004-05, Vol.309 (2), p.697
• Main Authors: Hou, Cuifen, Kirchner, Thomas, Singer, Monica, Matheis, Michele, Argentieri, Dennis, Cavender, Druie
• Format: Article
• Language: English
• Subjects: Analgesics - pharmacology; Animals; Binding Sites; Calcium - metabolism; Carrageenan; Cell Movement - drug effects; Cyclooxygenase 2; Dinoprostone - metabolism; Dogs; Drug Interactions; Edema - chemically induced; Edema - drug therapy; Enzyme Inhibitors - pharmacology; Estrenes - pharmacology; Humans; Interleukin-8 - pharmacology; Isoenzymes - antagonists & inhibitors; Isoenzymes - metabolism; Leukotriene B4 - pharmacology; Lipopolysaccharides - pharmacology; Macrophages, Peritoneal - drug effects; Membrane Proteins; Mice; Neutrophils - cytology; Neutrophils - drug effects; Peritoneal Lavage; Phospholipase C beta; Phospholipase D - metabolism; Prostaglandin-Endoperoxide Synthases - metabolism; Pyrrolidinones - pharmacology; Rats; Receptors, Glucocorticoid - metabolism; Tetradecanoylphorbol Acetate - pharmacology; Type C Phospholipases - antagonists & inhibitors
• ISSN: 0022-3565; 1521-0103
• DOI: 10.1124/jpet.103.060574

To investigate the role of phospholipase C (PLC) in inflammatory processes, we tested 1-(6-((17β-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1 H -pyrrole-2,5-dione (U73122), a widely used PLC inhibitor, in several in vitro and in vivo assays. We first examined the effects of U73122 on human phospholipase C-β (PLC-β) isozymes and found that U73122 significantly inhibited recombinant human PLC-β2, with an IC 50 of ∼6 μM. U73122 had little effect on PLC-β1, PLC-β3, or PLC-β4. Consistent with its ability to inhibit PLC-β2 enzymatic activity, U73122 reduced interleukin-8 and leukotriene B 4 -induced Ca 2+ flux and chemotaxis in human neutrophils in a concentration-dependent manner. In vivo, U73122 blocked carrageenan-induced hind paw edema in rats, carrageenan-induced macrophage and lymphocyte accumulation into subcutaneous chambers in dogs, lipopolysaccharide-induced macrophage, lymphocyte infiltration and prostaglandin E 2 production in a mouse peritonitis model, and 12- O -tetradecanoylphorbol-13-acetate-induced ear edema in mice. These results implicate PLC-dependent signaling pathways in the development of acute and chronic inflammatory responses in vivo.