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: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.
Project description:Here we investigate how glucocorticoids affect the response to Interferon gamma in human macrophages. Total RNA obtained from monocyte-derived macrophages exposed to Interferon gamma presceding exposure to fluticasone propionate or left untreated.
Project description:Virus infection induces the production of type I and type II interferons (IFN-I and IFN-II), cytokines that mediate the antiviral response. IFN-I (IFN-a and -b) induces the assembly of ISGF3 (interferon-stimulated gene factor 3), a multimeric transcriptional activation complex comprised of STAT1, STAT2 and IRF9. IFN-II (IFN-g) induces the homodimerization of STAT1 to form the GAF (gamma-activated factor) complex. ISGF3 and GAF bind specifically to distinct regulatory DNA sequences located upstream of IFN-I and II inducible genes, respectively, and activate the expression of distinct set of antiviral genes. The balance between the type I and type II IFN pathways plays a critical role in orchestrating the innate and adaptive immune systems. Here, we show that the phosphorylation of STAT1 by IKKε (IkB-related kinase epsilon) inhibits STAT1 homodimerization, and thus GAF formation, but does not disrupt ISGF3 formation. Therefore, virus and/or IFN-I activation of IKKε suppresses GAF-dependent transcription and promotes ISGF3-dependent transcription. In the absence of IKKε, GAF-dependent transcription is enhanced at the expense of ISGF3-mediated transcription, rendering cells less resistant to infection. We conclude that IKKε plays a critical role in regulating the balance between the IFN-I and IFN-II signaling pathways. ChIP-seq libraries were constructed with an antibody targeting STAT1 from bone marrow macrophages treated with interferon
Project description:Ultraviolet (UV) radiation is a major melanoma risk factor, yet underlying mechanisms remain poorly understood. Here we introduce a mouse model permitting fluorescence-aided melanocyte imaging and isolation following in vivo UV irradiation. We use expression profiling to show that activated neonatal skin melanocytes isolated following a melanomagenic UVB dose bear a distinct, persistent interferon-response signature, including genes associated with immunoevasion. UVB-induced melanocyte activation, characterized by aberrant growth and migration, was abolished by antibody-mediated systemic blockade of interferon-gamma (IFN-gamma), but not type-I interferons. IFN-gamma was produced by macrophages recruited to neonatal skin by UVB-induced chemokine receptor Ccr2 ligands. Admixed recruited skin macrophages enhanced transplanted melanoma growth by inhibiting apoptosis; notably, IFN-gamma blockade abolished macrophage-associated melanoma growth and survival. IFN-gamma-producing macrophages were identified in 70% of human melanomas examined. Our data reveal an unanticipated role for IFN-gamma in promoting melanocytic cell survival/immunoevasion, and suggest IFN-gamma-R signaling represents a novel therapeutic melanoma target. Biologic replicates of UVA- and UVB-treated mouse melanocytes, as well as untreated mouse melanocytes and mouse keratinocytes, were used to define melanocyte expression signatures associated with UV treatment.
Project description:Understanding how cells sense and respond to their environment, and how these responses are modulated by genetic variation, are fundamental biological problems, particularly for understanding how pathogenic organisms invade and manipulate the cells of the human immune system. Macrophages recognize and respond to many important human pathogens including HIV-1, Mycobacteria tuberculosis and Salmonella. This study will focus on the cellular response of human macrophages to Salmonella infection and how this response is modulated by the genetic bacground of the individual as well as additional pro-inflammatory stimulus (interferon-gamma priming). We will acquire 100 human induced pluripotent stem cell lines from the HipSci project, differentiate the cells in vitro into macrophages and expose them to four environmental conditions: (i) no stimulation, (ii) interferon-gamma (18h), (iii) Salmonella typhimurium SL1344 (5h), (iv) interferon-gamma (18h) + Salmonella (5h).Subsequently, we will isolate RNA from the samples for sequencing.
Project description:Natural killer (NK) cells are lymphocytes of the innate immune system that are involved in controlling tumors or microbial infections through the production of interferon gamma (IFN-γ). Granulocyte-colony stimulating factor (G-CSF) inhibits IFN-γ secretion by NK cells, but the mechanism underlying this effect remains unclear. Here, by comparing the multi-omics profiles of human NK cells before and after in vivo G-CSF treatment, we identified a pathway that was activated in response to G-CSF treatment, which suppressed IFN-γ secretion in NK cells. Specifically, our integrative genomic strategy revealed glucocorticoid receptor (GR) activation in NK cells that mediated the genomic response to G-CSF treatment. Activated GRs can inhibit secretion of IFN-γ by promoting interactions between suppressor of cytokine signaling 1 (SOCS1) promoter and enhancer, as well as increase the expression of SOCS1. Experiments in mice confirmed that G-CSF in vivo treatment significantly down-regulated IFN-γ secretion and up-regulated GR and SOCS1 expression in NK cells. In addition, GR blockade (RU486) significantly reversed the effects of G-CSF, demonstrating that GR up-regulates SOCS1 and inhibits the production of IFN-γ by NK cells.
Project description:Natural killer (NK) cells are lymphocytes of the innate immune system that are involved in controlling tumors or microbial infections through the production of interferon gamma (IFN-γ). Granulocyte-colony stimulating factor (G-CSF) inhibits IFN-γ secretion by NK cells, but the mechanism underlying this effect remains unclear. Here, by comparing the multi-omics profiles of human NK cells before and after in vivo G-CSF treatment, we identified a pathway that was activated in response to G-CSF treatment, which suppressed IFN-γ secretion in NK cells. Specifically, our integrative genomic strategy revealed glucocorticoid receptor (GR) activation in NK cells that mediated the genomic response to G-CSF treatment. Activated GRs can inhibit secretion of IFN-γ by promoting interactions between suppressor of cytokine signaling 1 (SOCS1) promoter and enhancer, as well as increase the expression of SOCS1. Experiments in mice confirmed that G-CSF in vivo treatment significantly down-regulated IFN-γ secretion and up-regulated GR and SOCS1 expression in NK cells. In addition, GR blockade (RU486) significantly reversed the effects of G-CSF, demonstrating that GR up-regulates SOCS1 and inhibits the production of IFN-γ by NK cells.
Project description:The systematic temporal gene expression analysis of primary macrophages activated under immune (interferon-gamma) and productive viral infection with murine cytomegalovirus (mCMV). The primary objective of the study is to define, in an unbiased manner, cause-and-effect relationships in the program of gene activation in this cellular system. The even spacing and time intervals (every 30 minutes) makes this study amenable to modelling of gene networks in the system.