Bromodomain-containing proteins bind acetylated lysine residues on histone tails and are involved in the recruitment of additional factors that mediate histone modifications and enable transcription. A compound, I-BET-762, that inhibits binding of an acetylated histone peptide to BRD4 and other proteins of the BET (bromodomain and extra-terminal domain) family, was previously shown to suppress the production of pro-inflammatory proteins by macrophages and block acute inflammation in mice. Here we investigate the effect of I-BET-762 on T cell function. We show that treatment of nave CD4+ T cells with I-BET-762 during early differentiation modulates subsequent cytokine production, and inhibits the ability of Th1-skewed cells to induce autoimmune pathogenesis in a model of experimental autoimmune encephalomyelitis (EAE) in vivo. The suppressive effects of I-BET-762 on T-cell mediated inflammation were not due to inhibition of expression of the pro-inflammatory cytokines, IFN-. or IL-17, but correlated with the ability to suppress GM-CSF production from CNS-infiltrating T cells, resulting in decreased recruitment of macrophages and granulocytes. The effects of I-BET-762 were distinct from those of the fumarate ester, dimethyl fumarate (DMF), a candidate drug for treatment of multiple sclerosis (MS). Our data suggest that I-BET and DMF could have complementary roles in the treatment of MS, and provide a strong rationale for inhibitors of BET-family proteins in the treatment of autoimmune diseases, based on their dual ability to suppress granulocyte and macrophage recruitment by T cells as well as production of pro-inflammatory proteins by macrophages.
Selective inhibition of CD4+ T-cell cytokine production and autoimmunity by BET protein and c-Myc inhibitors.
Specimen part
View SamplesWe sought to identify genes regulated by the transcription factor Th-POK (Zbtb7b) in liver Va14i NKT cells, by RNA microarray analysis of global gene expression in Va14i NKT cells from mice homozygous for the Th-POK-inactivating hd point mutation as compared with the same cell population isolated from heterozygous or wild-type age-matched mice.
The transcription factor Th-POK negatively regulates Th17 differentiation in Vα14i NKT cells.
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View SamplesInnate immune responses must be regulated in the intestine to prevent excessive inflammation. Here, using gene reporter mice, we show that a subset of mouse colonic macrophages constitutively produced the anti-inflammatory cytokine IL-10. In mice infected with Citrobacter rodentium, which is considered similar to enteropathogenic Escherichia coli infection in humans, macrophage IL-10 was required to prevent intestinal pathology and to promote survival. The synthesis of the proinflammatory cytokine IL-23 was significantly increased in infected mice with a myeloid cell specific deletion of IL-10 and the addition of IL-10 reduced in vitro IL-23 production by intestinal macrophages. Furthermore, blockade of IL-23 led to reduced morbidity and mortality in the context of macrophage IL-10 deficiency. Transcriptome analysis indicated that the reporter positive and negative colonic macrophage subsets were highly similar, but the reporter positive cells differed for the expression of CD163, an IL-10 target gene, suggesting an autocrine IL-10 signal, and when obtained from infected mice, they had reduced IL-23p19 mRNA. Interestingly, only transfer of the reporter positive cells could rescue IL-10 deficient infected mice. Therefore, these data indicate a pivotal role for a subset of intestinal macrophages that constitutively produces IL-10, perhaps acting in part in autocrine fashion, in controlling excessive innate immune activation, regulation of IL-23 production, and prevention of tissue damage after an acute bacterial infection in the intestine.
IL-10-producing intestinal macrophages prevent excessive antibacterial innate immunity by limiting IL-23 synthesis.
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