RESUMO
Bacterial endotoxin is a potent inducer of inflammatory response, including the induction of inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production, and the expression of cyclo-oxygenase (COX)-2 and tumor necrosis factor (TNF)-alpha in inflammatory cells. In the present study, we investigated the effects of pharmacological inhibition of Janus kinase (JAK) 3 on the production of these proinflammatory molecules in macrophages exposed to bacterial endotoxin (lipopolysaccharide; LPS). JAK3 inhibitors WHI-P154 (4-(3'-bromo-4'-hydroxylphenyl)-amino-6,7-dimethoxyquinazoline) and its derivative WHI-P131 inhibited LPS-induced iNOS expression and NO production in a dose-dependent manner. WHI-P154 inhibited the activation of signal transducer and activator of transcription (STAT) 1 and the expression of iNOS mRNA but it had no effect on iNOS mRNA decay when determined by actinomycin D assay. The JAK3 inhibitor had no effect on COX-2 expression, and TNF-alpha production was slightly inhibited only at higher drug concentrations (30 microM). In addition, WHI-P154 inhibited iNOS expression and NO production also in human epithelial cells. Our results suggest that JAK3 inhibition modulates human and murine iNOS expression and NO production in response to inflammatory stimuli.
Assuntos
Ciclo-Oxigenase 2/biossíntese , Janus Quinase 3/antagonistas & inibidores , Lipopolissacarídeos/imunologia , Macrófagos/efeitos dos fármacos , Macrófagos/enzimologia , Óxido Nítrico Sintase Tipo II/biossíntese , Quinazolinas/farmacologia , Fator de Necrose Tumoral alfa/biossíntese , Linhagem Celular , Ciclo-Oxigenase 2/genética , Regulação para Baixo/imunologia , Humanos , Interferon gama/antagonistas & inibidores , Interferon gama/fisiologia , Ativação de Macrófagos/efeitos dos fármacos , Ativação de Macrófagos/imunologia , Macrófagos/imunologia , Óxido Nítrico/antagonistas & inibidores , Óxido Nítrico/biossíntese , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/genética , Inibidores de Proteínas Quinases/farmacologia , Fator de Transcrição STAT1/antagonistas & inibidores , Fator de Transcrição STAT1/metabolismo , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Fator de Necrose Tumoral alfa/genéticaRESUMO
In inflammation, inducible nitric oxide synthase (iNOS) produces nitric oxide (NO), which modulates inflammatory processes. We investigated the effects of Janus kinase (JAK) inhibitors, AG-490 and WHI-P154, on iNOS expression and NO production in J774 murine macrophages stimulated with interferon-gamma (IFN-gamma). JAK inhibitors AG-490 and WHI-P154 decreased IFN-gamma-induced nuclear levels of signal transducer and activator of transcription 1alpha (STAT1alpha). JAK inhibitors AG-490 and WHI-P154 decreased also iNOS protein and mRNA expression and NO production in a concentration-dependent manner. Neither of the JAK inhibitors affected the decay of iNOS mRNA when determined by actinomycin D assay. Our results suggest that the inhibition of JAK-STAT1-pathway by AG-490 or WHI-P154 leads to the attenuation of iNOS expression and NO production in IFN-gamma-stimulated macrophages.