Interferon-stimulated gene expression in STAT1 knockout cells
Ontology highlight
ABSTRACT: STAT1 plays a cental role in the induction of interferon-stimulated genes, but interferon alpha can activate a STAT1-independent pathway that leads to gene expression. We performed microarray analysis to examine whether like interferon alpha, interferon lambda, a newly discovered interferon, can induce the expression of interferon-stimulated genes in the absence of STAT1. Control and STAT1 knockout Huh-7.5 hepatoma cells were left untreated or treated with 1000 U/ml of human interferon alpha 2a or interferon lambda 1 (PBL) for 24 h, and total RNA was extracted. Sense-strand DNA was generated from 200 ng of total RNA, fragmented, and labeled using a GeneChip WT Plus Reagent Kit (Affymetrix). Six samples were obtained and each sample was anlyzed using one GeneChip.
Project description:STAT1 plays a cental role in the induction of interferon-stimulated genes, but interferon alpha can activate a STAT1-independent pathway that leads to gene expression. We performed microarray analysis to examine whether like interferon alpha, interferon lambda, a newly discovered interferon, can induce the expression of interferon-stimulated genes in the absence of STAT1.
Project description:Although type III interferons (IFN), also known as IFN-λ or IL28/IL-29, restrict infection by several viruses, their mechanism of inhibitory action has remained uncertain. We used recombinant IFN-λ and mice lacking the IFN-λ receptor (IFNLR1) to evaluate the effect of IFN-λ on infection with West Nile virus (WNV), an encephalitic flavivirus. Cell culture studies in keratinocytes and dendritic cells showed no direct antiviral effect of exogenous IFN-λ even though ISGs were induced. Correspondingly, we observed no differences in WNV burden between wild-type and Ifnlr1-/- mice in the draining lymph node, spleen, and blood. However, we detected earlier dissemination and increased WNV infection in the brain and spinal cord of Ifnlr1-/- mice, yet this was not associated with a direct antiviral effect on infection of neurons. Instead, an increase in blood-brain barrier (BBB) permeability was observed in Ifnlr1-/- mice. Accordingly, treatment of mice with pegylated IFN-λ2 resulted in decreased BBB permeability, reduced WNV infection in the brain without impacting viremia, and improved survival against lethal virus challenge. An in vitro model of the BBB showed that IFN-λ signaling in brain microvascular endothelial cells increased transendothelial electrical resistance, decreased virus movement across the barrier, and modulated tight junction protein localization in a protein synthesis- and STAT1-independent manner. Our data establish a novel indirect antiviral function of IFN-λ in which non-canonical signaling through IFNLR1 tightens the BBB and restricts viral neuroinvasion and pathogenesis. This finding suggests new clinical applications for IFN-λ in treating viral or autoimmune diseases. Transcriptome profiling of bone-marrow derived Dendritic cells(BMDCs), treated with either Serum Free Media(Mock), interferon beta(IFNb), or interferon lambda(IFNL) for 6 hours.
Project description:The transcriptome of Huh7 and Huh7.5 was sequenced from cells treated with interferon alpha (IFNα), beta (IFNβ) or lambda (IFNλ) for 8 hours. Each treatment was compared to respective mock-treated cells in 6 pairwise comparisons, for a total of 43 samples classified in 12 experimental conditions. Cells were treated for 8h with 10ng/ml of Interferon-α2A, 5000 U/ml of Interferon-β1A or 100ng/ml of interferon-λ3 prior RNA extraction and library preparation. Mock-treated cells were used as control for each treatment. 3 to 4 biological replicates were analysed for each biological condition. Libraries for Illumina sequencing were constructed by polyA selection with the Illumina Kit. A paired end (2x100) run was performed.
Project description:We report the results of chromatin immunoprecipitation following by high-thoughput tag sequencing (ChIP-Seq) using the GA II platform from Illumina for the human transcription factor STAT1 in HeLa S3 cells. The STAT1 ChIP was performed using HeLa S3 cells that are stimulated using gamma-interferon. We have also generated a seqenced input DNA dataset for gamma-interferon stimulated HeLa S3 cells. Raw data for this study is available for download from the Short Read Archive database at: http://www.ncbi.nlm.nih.gov/Traces/sra/sra.cgi?study=SRP000703. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf Examination of the STAT1 transcription factor in Human HeLa S3.
Project description:Hepatitis C virus (HCV) infection is primarily treated with a pegylated interferon alpha based therapy, a regime that induces antiviral effects through the upregulation of many interferon-stimulated genes (ISGs). Whilst a number of anti-HCV ISGs have previously been identified, others may also be involved. Micorarrays were used to validate the presence of ISGs within subtracted libraries generated using the related techniques of suppression subtractive hybridisation and mirror orientation selection, which had initally been impllemented to isolate clones of ISGs following the interferon-alpha treatment of Huh-7 cells. Microarray data was generated for both untreated and interferon-alpha treated Huh-7 cells. No replicates were performed, however the microarray data was verified via the use of non-parametric (spearman) correlation analysis with RT-PCR data that had been generated using the same Huh-7 cell total RNA samples as the microarray experiments earlier.
Project description:Interferon-alpha (pegylated interferon and ribavirin) is used as standard-of-care therapeutic for chronic hepatitis C virus infection. Besides good cure in some patients other patients do not benefit from the treatment dependent on the virus type and host factors. One class of putative effector proteins is the family of Suppressors of cytokine signalling (SOCS). They act in a classical negative feedback-loop against the action of interferons and many other cytokines. It has been proven that some of them, in particular SOCS1 and SOCS3, inhibit the expression of interferon induced antiviral proteins. Their mode of action depends on the signal they are interfering with. In relation to the interferon-gamma pathway, they are thought to act on the interferon-alpha receptors by masking its recognition site for the Janus kinases (JAK), by blocking the kinase activity of the JAKs and coincidentally hindering STAT molecules from binding to the kinases. They are also thought to ubiquitinate the JAKs resulting in their proteosomal degradation. The function of SOCS proteins in suppressing the interferon-alpha pathway has not yet been characterized exhaustively. This study should unveil links to understand the resistance in interferon-alpha therapy. As results we got almost complete silencing of JAK-STAT signaling in SOCS1 over-expressing cells and tissue-dependent partially suppressed gene induction in SOCS3 over-expressing cell lines. Two human cancer cell lines (ME-15, HuH-7) were stably transfected with pcDNA3.1-SOCS plasmids in presence of geneticin and daughter cell lines were generated after singularization of cells. Next, original cell lines as well as SOCS1 and SOCS3 over-expressing cell lines were treated with 1000 U/ml interferon-alpha for 4 or 24 hours or in normal culture medium. Cells lines obtained from SOCS4 plasmid transfections were screened as additional control. Gene expression levels of cell cultured in control (0 for 4 hours, 2 for 24 hours) or interferon-alpha supplemented medium for 4 hours (1) or 24 hours (4) were analyzed. mRNA abundance was measured in triplicates using 12x8-sample commercial Illumina microarrays (HumanRef 8, version 3) and scanner system (iScan) as well as reagents recommend by Illumina (IlluminaM-BM-. TotalPrep Kit).
Project description:We used microarrays to compare interferon-alpha (IFNa)- and interferon-gamma (IFNg)-stimulated genes under an equivalent biological input. The goal was to compare IFNa- and IFNg-stimulated genes, as well as to identify common and distinct sets of type I and II ISGs. Bone marrow macrophages derived from mouse bone marrow in M-CSF for 7 days. The cells were stimulated with 62U/mL IFNa and 1U/mL of IFNg for 2.5 hrs in culture. These concentrations induced equivalent STAT1 phosphorylation in BMMs.
Project description:Collaborative Cross (CC) mouse embryonic fiborolasts (MEF) cells obtained from the eight Founder animals [PWK/PhJ, NZO/HILtJ, NOD/ShiLtJ, WSB/EiJ, A/J, CAST, C57BL/6J, and 129/SvlmJ] were immortalized and the cell lines used to assess differences in transcriptional responses following treatment with type I, II and III recombinant mouse interferon. We collected transcriptome profiles for 8 CC MEF cell lines stimulated with either IFN-α or IFN-β for a total of 16 different biological conditions. Treated and mock samples were collected at 18 hr post-treatment and RNAs extracted and subjected to microarray.
Project description:Gene regulation by cytokine-activated STAT transcription factors requires serine phosphorylation within the transactivation domain (TAD). STAT1 and STAT3 TAD phosphorylation was reported to occur upon promoter binding by an unknown kinase. Here we show that the Mediator CDK8 module phosphorylates S727 of the STAT1 TAD in the interferon (IFN) signaling pathway as well as the TADs of other STATs. Microarray analysis reveals that CDK8-mediated STAT1 TAD phosphorylation positively or negatively regulates over 40% of IFN-gamma-responsive genes, and RNA polymerase II occupancy correlates with gene expression changes. This selective regulation occurs despite CDK8 occupancy and STAT1 S727 phosphorylation at both S727 phosphorylation-dependent and -independent IFN-gamma target genes. Independently of its role as STAT1 S727 kinase CDK8 acts as a positive regulator of IFN-gamma responses. These data reveal a dual input of CDK8 in STAT1-controlled transcription and propose a key role for CDK8 in TAD phosphorylation of other STATs during cytokine responses. STAT1 WT and STAT1 S727A mouse fibroblasts were treated with siRNA to CDK8 (siCdk8 smart pool, On Target Plus, Dharmacon) and control siRNA (siCtrl) and stimulated with IFN-gamma for 4 h or left untreated. Total RNA from three independent experiments for each treatment and each genotype was isolated from cells using Trizol reagent (Invitrogen) following the manufactures protocol and used for expression analysis using Agilent Whole Mouse Genome Microarrays, 8x60K. Standard protocols for labeling and hybridization were followed. In brief, fluorescent cRNA was generated using Low Input Quick Amp Labeling Kit (Agilent). The amplified cyanine 3-labeled cRNA samples were then purified using SV Total RNA Isolation System (Promega) and hybridized to microarray slides. Microarray slides were washed and scanned with an Agilent Scanner. Note: The outlier array #10 [SA.CDK.gamma.R3] was removed from subsequent analysis and its processed data was not provided. However, its raw data file has been linked as a supplementary file at the foot of the Series record.