RESUMO
Interleukin-33 (IL-33) is associated with several important immune-mediated disorders. However, its role in uveitis, an important eye inflammatory disease, is unknown. Here, we investigated the function of IL-33 in the development of experimental autoimmune uveitis (EAU). IL-33 and IL-33 receptor (ST2) were expressed in murine retinal pigment epithelial (RPE) cells in culture, and IL-33 increased the expression of Il33 and Mcp1 mRNA in RPE cells. In situ, IL-33 was highly expressed in the inner nuclear cells of the retina of naïve mice, and its expression was elevated in EAU mice. ST2-deficient mice developed exacerbated EAU compared with WT mice, and administration of IL-33 to WT mice significantly reduced EAU severity. The attenuated EAU in IL-33-treated mice was accompanied by decreased frequency of IFN-γ+ and IL-17(+) CD4+ T cells and reduced IFN-γ and IL-17 production but with increased frequency of IL-5(+) and IL-4(+) CD4 T cells and IL-5 production in the draining lymph node and spleen. Macrophages from the IL-33-treated mice show a significantly higher polarization toward an alternatively activated macrophage phenotype. Our results therefore demonstrate that the endogenous IL-33/ST2 pathway plays an important role in EAU, and suggest that IL-33 represents a potential option for treatment of uveitis.
Assuntos
Doenças Autoimunes/tratamento farmacológico , Interleucinas/uso terapêutico , Receptores de Interleucina/genética , Uveíte/tratamento farmacológico , Animais , Doenças Autoimunes/imunologia , Linfócitos T CD4-Positivos/imunologia , Células Cultivadas , Técnicas de Cocultura , Modelos Animais de Doenças , Olho/imunologia , Olho/patologia , Proteínas do Olho/imunologia , Inflamação/tratamento farmacológico , Inflamação/imunologia , Interferon gama/biossíntese , Proteína 1 Semelhante a Receptor de Interleucina-1 , Interleucina-17/biossíntese , Interleucina-33 , Interleucina-4/biossíntese , Interleucina-5/biossíntese , Interleucinas/biossíntese , Interleucinas/genética , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , RNA Mensageiro/biossíntese , Receptores de Interleucina/biossíntese , Epitélio Pigmentado da Retina/citologia , Epitélio Pigmentado da Retina/metabolismo , Uveíte/imunologiaRESUMO
Interleukin (IL)-33, a member of the IL-1 cytokine family, is an important modulator of the immune system associated with several immune-mediated disorders. High levels of IL-33 are expressed by the central nervous system (CNS) suggesting a potential role of IL-33 in autoimmune CNS diseases. We have investigated the expression and function of IL-33 in the development of experimental autoimmune encephalomyelitis (EAE) in mice. We report here that IL-33 and its receptor ST2 (IL-33Rα) are highly expressed in spinal cord tissue, and ST2 expression is markedly increased in the spinal cords of mice with EAE. Furthermore, ST2-deficient (ST2(-/-) ) mice developed exacerbated EAE compared with wild-type (WT) mice while WT, but not ST2(-/-) EAE mice treated with IL-33 developed significantly attenuated disease. IL-33-treated mice had reduced levels of IL-17 and IFN-γ but produced increased amounts of IL-5 and IL-13. Lymph node and splenic macrophages of IL-33-treated mice showed polarization toward an alternatively activated macrophage (M2) phenotype with significantly increased frequency of MR(+) PD-L2(+) cells. Importantly, adoptive transfer of these IL-33-treated macrophages attenuated EAE development. Our data therefore demonstrate that IL-33 plays a therapeutic role in autoimmune CNS disease by switching a predominantly pathogenic Th17/Th1 response to Th2 activity, and by polarization of anti-inflammatory M2 macrophages.
