Portal de Periódicos da CAPES

Artigo Acesso aberto Produção Nacional Revisado por pares

BIBTEX RIS

Inhibition of a p38/Stress-Activated Protein Kinase-2-Dependent Phosphatase Restores Function of IL-1 Receptor-Associated Kinase-1 and Reverses Toll-Like Receptor 2- and 4-Dependent Tolerance of Macrophages

2003; American Association of Immunologists; Volume: 171; Issue: 3 Linguagem: Inglês

10.4049/jimmunol.171.3.1456

1550-6606

Catherine Ropert, Meire Closel, Andréa Carla Leite Chaves, Ricardo T. Gazzinelli,

Biochemical and Molecular Research

Abstract Pretreatment of macrophages with Toll-like receptor (TLR)2 or TLR4 agonists leads to a stage of cell hyporesponsiveness to a second stimulation with TLR agonists. This tolerance state is accompanied by the repression of IL-1 receptor-associated kinase-1, mitogen-activated protein kinases, and IκB phosphorylation and expression of genes encoding proinflammatory cytokines, like IL-1β and TNF-α. In this report, we demonstrated that mucin-like glycoprotein (tGPI-mucin) of Trypanosoma cruzi trypomastigotes (TLR2 agonist) and LPS (TLR4 agonist) induce cross-tolerance in macrophages and we addressed the role of phosphatase activity in this process. Analysis of the kinetic of phosphatase activity induced by tGPI-mucin or LPS revealed maximum levels between 12 and 24 h, which correlate with the macrophage hyporesponsiveness stage. The addition of okadaic acid, an inhibitor of phosphatase activity, reversed macrophage hyporesponsiveness after exposure to either LPS or tGPI-mucin, allowing phosphorylation of IL-1R-associated kinase-1, mitogen-activated protein kinases, and ΙκB and leading to TNF-α gene transcription and cytokine production. Furthermore, pretreatment with either the specific p38/stress-activated protein kinase-2 inhibitor (SB203580) or the NF-κB translocation inhibitor (SN50) prevented the induction of phosphatase activity and hyporesponsiveness in macrophage, permitting cytokine production after restimulation with LPS. These results indicate a critical role of p38/stress-activated protein kinase-2 and NF-κB-dependent phosphatase in macrophage hyporesponsiveness induced by microbial products that activate TLR2 and TLR4.