Project description:Mechanisms by which IFN-γ activates genes to promote macrophage activation are well studied, but little is known about mechanisms and functions of IFN-γ-mediated gene repression. We used an integrated transcriptomic and epigenomic approach to analyze chromatin accessibility, histone modifications, transcription factor binding, and gene expression in IFN-γ-primed human macrophages. IFN-γ suppressed basal expression of genes corresponding to an ‘M2’-like homeostatic/reparative phenotype. IFN-γ repressed genes by suppressing the function of enhancers enriched for binding by transcription factor MAF. Mechanistically, IFN-γ ‘disassembled’ a subset of enhancers by inducing coordinate suppression of binding by MAF, lineage-determining transcription factors, and chromatin accessibility. Genes associated with MAF-binding disassembled enhancers were suppressed in rheumatoid arthritis macrophages, revealing a disease-associated ‘negative IFN-γ signature’. These results identify enhancer inactivation and disassembly as a mechanism of IFN-γ-mediated gene repression, and MAF as a regulator of the macrophage enhancer landscape that is suppressed by IFN-γ to augment macrophage activation.
Project description:Mechanisms by which IFN-γ activates genes to promote macrophage activation are well studied, but little is known about mechanisms and functions of IFN-γ-mediated gene repression. We used an integrated transcriptomic and epigenomic approach to analyze chromatin accessibility, histone modifications, transcription factor binding, and gene expression in IFN-γ-primed human macrophages. IFN-γ suppressed basal expression of genes corresponding to an ‘M2’-like homeostatic/reparative phenotype. IFN-γ repressed genes by suppressing the function of enhancers enriched for binding by transcription factor MAF. Mechanistically, IFN-γ ‘disassembled’ a subset of enhancers by inducing coordinate suppression of binding by MAF, lineage-determining transcription factors, and chromatin accessibility. Genes associated with MAF-binding disassembled enhancers were suppressed in rheumatoid arthritis macrophages, revealing a disease-associated ‘negative IFN-γ signature’. These results identify enhancer inactivation and disassembly as a mechanism of IFN-γ-mediated gene repression, and MAF as a regulator of the macrophage enhancer landscape that is suppressed by IFN-γ to augment macrophage activation.
Project description:Mechanisms by which IFN-γ activates genes to promote macrophage activation are well studied, but little is known about mechanisms and functions of IFN-γ-mediated gene repression. We used an integrated transcriptomic and epigenomic approach to analyze chromatin accessibility, histone modifications, transcription factor binding, and gene expression in IFN-γ-primed human macrophages. IFN-γ suppressed basal expression of genes corresponding to an ‘M2’-like homeostatic/reparative phenotype. IFN-γ repressed genes by suppressing the function of enhancers enriched for binding by transcription factor MAF. Mechanistically, IFN-γ ‘disassembled’ a subset of enhancers by inducing coordinate suppression of binding by MAF, lineage-determining transcription factors, and chromatin accessibility. Genes associated with MAF-binding disassembled enhancers were suppressed in rheumatoid arthritis macrophages, revealing a disease-associated ‘negative IFN-γ signature’. These results identify enhancer inactivation and disassembly as a mechanism of IFN-γ-mediated gene repression, and MAF as a regulator of the macrophage enhancer landscape that is suppressed by IFN-γ to augment macrophage activation.
Project description:Macrophages are major effector cells and antigen presenting cells of the innate immune system and classical activation of macrophage function requires interferon–γ (IFN-γ) pretreatment (priming) and TLR stimuli, which promotes inflammatory responses though high levels of pro-inflammatory cytokines and lower level of the anti-inflammatory cytokines, resulting in microbicidal and tumoricidal effect. However, the underlying molecular mechanism of IFN-γ priming remains elusive. In this study, we explored the effect of IFN-γ on macrophages at miRNA level and discovered that miR-3473b, which was down-regulated after IFN-γ priming, could attenuate the priming effect of IFN-γ. Molecular study revealed that miR-3473b promoted Akt/GSK3 signaling and IL-10 production through directly targeting PTEN to suppress inflammatory response and tumor-suppressing capability of macrophages. In summary, our data demonstrate that IFN-γ beef up macrophage inflammatory response and tumor suppressing capacity by limiting miR-3473b-mediated PTEN suppression. Our work identified an IFN-γ/miR-3473b/Akt axis in the regulation of macrophage function and activation. the assay was performed with 5 μg total RNA samples from both normal BMM (labeled by Cy3) and BMM primed by IFN-γ (100U/ml) for 4 h(labeled by Cy5), normal BMM serves as control.
Project description:Here, we report that IFN-γ derived from CD8+ T cells promotes the transcription of ACOD1 in macrophages and the subsequent production of itaconate. To explore the molecular mechanism by which IFN-γ induces ACOD1 in macrophages, we analysed the transcriptome of IFN-γ-treated BMDMs by RNA-seq. Enrichment analysis of differentially expressed genes (DEGs) revealed that the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway was significantly enriched in IFN-γ-treated BMDMs compared with the control group.
Project description:Interferon-γ (IFN-γ) or interleukin-4 (IL-4) prime macrophages towards classical (M1) or alternative (M2) activation, respectively. How IFN-γ and IL-4 prime epigenetic responses by altering expression of histone modifying enzymes and how this affects M1/M2 polarization is incompletely understood.