Project description:Variation in individuals' adaptive immune response is believed to influence susceptibility to complex diseases in humans. The genetic basis of such variation is poorly understood. We measured gene expression from resting and activated CD4+ T cells derived from the peripheral blood of healthy individuals. We activated the primary T cells with anti-CD3/CD28 beads alone or with IFNb or Th17 polarizing cytokines. We collected peripheral blood from each human donor. We isolated peripheral blood mononuclear cells by Ficoll, and negatively selected for CD4+ T cells using RosettaSep. We then either left cells unstimulated or stimulated them with beads conjugated with anti-CD3 and anti-CD28 either without additional cytokines, or with IFNb, or with Th17 cocktail. Cells were harvest at up to 8 time points (0hr, 45min, 2hr, 4hr, 10hr, 24hr, 48hr and 72hr), lysed and RNA isolated to be profiled on microarray.
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:Emerging data suggest that many immunoreceptors, all of which use a conserved ITAM-module for their signaling, can couple with members of additional classes of membrane receptors to deliver unique signal(s) to the cell. Using functional and gene expression analysis we describe the role for the tonic signaling through Fcg-chain, the major ITAM-module of the innate immune system, in modifying cytokine responses in MF. Peritoneal MF were left unstimulated or were stimulated in duplicates for 6 hrs with IFNγ. cDNA was analyzed using 8-sample Mouse Ref-8 v2.0 Illumina array. Expressed genes were defined as those with p<0.05, and their relative expression values were calculated using average of two WT unstimulated samples as calibrator.
Project description:IFNg is a pro-inflammatory and pro-atherogenic cytokine that leads to macrophage activation. Adenosine has well-documented anti-inflammatory properties. We used microarrays to compare the global gene expression profile in mouse macrophages stimulated with IFNg alone and those cells treated with IFNg and adenosine. We determined that adenosine suppressed the expression of many IFNg-regulated pro-inflammatory cytokines, chemokines, and other pro-atherogenic genes. Keywords: treatment response RAW 264.7 cells were treated for 4 hours with either IFNg or IFNg plus adenosine. Following treatment, total RNA was extracted and treatment groups were pooled from 2 separate experiments for hybridization of Affymetrix microarrays.
Project description:Dendritic cells (DCs) are the most potent antigen (Ag)-presenting cells. Whereas immature DCs down-regulate T cell responses to induce/maintain immunological tolerance, mature DCs promote immunity. To amplify their functions, DCs communicate with neighboring DCs through soluble mediators, cell-to-cell contact and vesicle exchange. Transfer of nanovesicles (<100nm) derived from the endocytic pathway (termed exosomes) represents a novel mechanism of DC-to-DC communication. The facts that exosomes contain exosome-shuttle microRNAs (miRNAs), and DC functions can be regulated by exogenous miRNAs, suggest that DC-to-DC interactions could be mediated through exosome-shuttle miRNAs, an hypothesis that remains to be tested. Importantly, the mechanism of transfer of exosome-shuttle miRNAs from the exosome lumen to the cytosol of target cells is unknown. Here, we demonstrate that DCs release exosomes with different miRNAs depending on the maturation of the DCs. By visualizing spontaneous transfer of exosomes between DCs, we demonstrate that exosomes fused with the target DCs, the latter followed by release of the exosome content into the DC cytosol. Importantly, exosome-shuttle miRNAs are functional, as they repress target mRNAs of acceptor DCs. Our findings unveil a mechanism of transfer of exosome-shuttle miRNAs between DCs and its role as a means of communication and post-transcriptional regulation between DCs. The study has analyzed the microRNA content of 4 samples of immature exosomes, 4 samples of matures exosomes, 2 samples of immature bone-marrow-derived DCs, and 2 samples of mature bone marrow-derived DCs.
Project description:Wild type HIV-1 can infect macrophages to establish productive infection without triggering innate immune receptors or type 1 interferon responses that would otherwise restrict virus propagation. We found that HIV-1 capsid mutants that disrupt capsid interactions with two host factors CPSF6 and cyclophillin A do not replicate in macrophages because they do trigger interferon responses. Genome-wide transcriptional profiling was used to compare the repertoire of interferon stimulated genes induced by these capsid mutants after 24Êh with stimulation of macrophages with interferon-beta or with the RNA analogue Poly IC.
Project description:Cultured epidermal keratinocyte controls used for IFNg, TNFa and IL1 treatment. Interferon (IFN)-gamma, is a multifunctional, immunomodulatory cytokine with cell type-specific antiviral activities, particularly important in skin, where it is implicated in many diseases ranging from warts to psoriasis and cancer. Since epidermis is our first line of defence against many viruses, we investigated the molecular processes regulated by IFN-gamma in keratinocytes using DNA microarrays. We identified the IFN-gamma-regulated keratinocyte-specific genes in keratinocytes, IFN-gamma-induced tight junction proteins, presumably to deny viruses paracellular routes of infection. Furthermore, differing from published data, we find that IFN-gamma suppressed the expression of keratinocytes differentiation markers including desmosomal proteins, cornified envelope components and suprabasal cytokeratins. Inhibition of differentiation may interfere with the epidermal tropism of viruses that require differentiating cells for growth, for example, papillomaviruses. As in other cell types, IFN-gamma induced HLA, cell adhesion and proteasome proteins, facilitating leukocyte attraction and antigen-presentation by keratinocytes. IFN-gamma also induced chemokine/cytokines specific for mononuclear cells. IFN-gamma suppressed the expression of over 100 genes responsible for cell cycle, DNA replication and RNA metabolism, thereby shutting down many nuclear processes and denying viruses a healthy cell in which to replicate. Thus, uniquely in keratinocytes, IFN-gamma initiates a well-organized molecular programme boosting host antiviral defences, obstructing viral entry, suppressing cell proliferation and impeding differentiation.
Project description:CD4+ T follicular helper cells (TFH) are critical for the formation and function of B cell responses to infection or immunization, but also play an important role in autoimmunity. The factors that contribute to the differentiation of this helper cell subset are incompletely understood, although several cytokines including IL-6, IL-21 and IL-12 can promote TFH cell formation. Yet, none of these factors, nor their downstream cognate STATs, have emerged as non-redundant, essential drivers of TFH cells. This suggests a model in which multiple factors can contribute to the phenotypic characteristics of TFH cells. As type I interferons (IFNs) are often generated in immune responses, we set out to investigate if these factors are relevant to TFH cell differentiation. Type I IFNs promote Th1 responses, thus one possibility was these factors antagonized TFH-expressed genes. However, we show that type I IFNs (IFN-α/β) induced Bcl6 expression, the master regulator transcription factor for TFH cells, and CXCR5 and PD-1 (encoded by Pdcd1), key surface molecules expressed by TFH cells. In contrast, type I IFNs failed to induce IL-21, the signature cytokine for TFH cells. The induction of Bcl6 was regulated directly by STAT1, which bound to the Bcl6, Cxcr5 and Pdcd1 loci. These data suggest that type I IFNs (IFN-α/β) and STAT1 can contribute to some features of TFH cells but are inadequate in inducing complete programming of this subset. The role of STAT1 in type I interferon treated CD4+ T cells was investigated by Chip-seq of STAT1.