IL-1 beta converting enzyme is a target for nitric oxide-releasing aspirin: new insights in the antiinflammatory mechanism of nitric oxide-releasing nonsteroidal antiinflammatory drugs.
Caspase-1, the IL-1beta converting enzyme (ICE), is required for intracellular processing/maturation of IL-1beta and IL-18. NO releasing nonsteroidal antiinflammatory drugs (NSAIDs) are a new class of NSAID derivatives that spare the gastric mucosa. Here, we tested the hypothesis that NCX-4016, a NO-aspirin derivative, inhibits proinflammatory cytokine release from endotoxin (LPS)-challenged monocytes. Our results demonstrated that exposing LPS-stimulated human monocytes to NCX-4016 resulted in a 40-80% inhibition of IL-1beta, IL-8, IL-12, IL-18, IFN-gamma, and TNF-alpha release with an EC(50) of 10-20 microM for IL-1beta and IL-18. Incubating LPS-primed monocytes with NCX-4016 resulted in intracellular NO formation as assessed by measuring nitrite/nitrate, intracellular cGMP concentration, and intracellular NO formation. Exposing LPS-stimulated monocytes to aspirin or celecoxib caused a 90% inhibition of prostaglandin E(2) generation but had no effect on cytokine release. NCX-4016, similar to the NO donor S-nitroso-N-acetyl-D-L-penicillamine, inhibited caspase-1 activity with an EC(50) of approximately 20 microM. The inhibition of caspase-1 by NCX-4016 was reversible by the addition of DTT, which is consistent with S-nitrosylation as the mechanism of caspase-1 inhibition. NCX-4016, but not aspirin, prevented ICE activation as measured by assessing the release of ICE p20 subunit. IL-18 immunoneutralization resulted in a 60-80% reduction of IL-1beta, IL-8, IFN-gamma, and TNF-alpha release from LPS-stimulated monocytes. Taken together, these data indicate that incubating human monocytes with NCX-4016 causes intracellular NO formation and suppresses IL-1beta and IL-18 processing by inhibiting caspase-1 activity. Caspase-1 inhibition is a new, cycloxygenase-independent antiinflammatory mechanism of NO-aspirin.
Fiorucci
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Dipartimento di Medicina Clinica e Sperimentale, Clinica di Gastroenterologia ed Epatologia, Università degli Studi di Perugia. fiorucci@unipg.it
Santucci
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L
Cirino
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Mencarelli
A
A
Familiari
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Soldato
P D
PD
Morelli
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A
D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000378:metabolism* / Q000494:pharmacology; D001241:Aspirin / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D020170:Caspase 1 / Q000378:metabolism* / Q000502:physiology; D061945:Caspase Inhibitors; D002478:Cells, Cultured; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D016207:Cytokines / Q000037:antagonists & inhibitors / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D007166:Immunosuppressive Agents / Q000378:metabolism / Q000494:pharmacology; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007424:Intracellular Fluid / Q000276:immunology / Q000378:metabolism; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D009000:Monocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000378:metabolism*; D009603:Nitroso Compounds / Q000378:metabolism
D000894:Anti-Inflammatory Agents, Non-Steroidal; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D016207:Cytokines; D007166:Immunosuppressive Agents; D007375:Interleukin-1; D008070:Lipopolysaccharides; D020030:Nitric Oxide Donors; D009603:Nitroso Compounds; D020170:Caspase 1; C102148:nitroaspirin; D001241:Aspirin