IFN-γ induced transcriptional profile of A549 cells in absence of key transcriptional regulators IRF1 and NF2
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE215771 | GEO | 2023/12/15
REPOSITORIES: GEO
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Project description:Type I interferons (IFN-I) are critical in antimicrobial and antitumor defense. Although IFN-I signal via the interferon-stimulated gene factor 3 (ISGF3) complex consisting of STAT1, STAT2 and IRF9, IFN-I can mediate significant biological effects via ISGF3-independent pathways. For example, absence of STAT1, STAT2 or IRF9 exacerbates neurological disease in transgenic mice with CNS-production of IFN-gamma. Here we determined the role of IFN-I-driven, ISGF3-independent signaling in regulating global gene expression in STAT1, STAT2 or IRF9-deficient murine mixed glial cell cultures (MGCs). Compared with WT, the expression of IFN-gamma-stimulated genes (ISGs) was reduced in number and magnitude in MGCs that lacked STAT1, STAT2 or IRF9. There were significantly fewer ISGs in the absence of STAT1 or STAT2 versus the absence of IRF9. The majority of ISGs regulated in the STAT1-, STAT2- or IRF9-deficient MGCs individually were shared with WT. However, only a minor number of ISGs were common to WT, STAT1-, STAT2- and IRF9-deficient MGCs. While signal pathway activation in response to IFN-gamma was rapid and transient in WT MGCs, this was delayed and prolonged and correlated with increased numbers of ISGs expressed at 12 h versus 4 h IFN-gamma exposure in all three IFN-I-signaling-deficient MGCs. In conclusion, (1) IFN-I can mediate ISG expression in MGCs via ISGF3-independent signaling pathways but with reduced efficiency, with delayed and prolonged kinetics and is more dependent on STAT1 and STAT2 than IRF9, and (2) signaling pathways not involving STAT1, STAT2 or IRF9 play a minor role only in mediating ISG expression in MGCs.
2017-02-15 | E-MTAB-5445 | biostudies-arrayexpress
Project description:Intracellular pathogens including the apicomplexan and opportunistic parasite Toxoplasma gondii profoundly modify their host cells in order to establish infection. We have shown previously that intracellular T. gondii inhibit up-regulation of regulatory and effector functions in murine macrophages (MΦ) stimulated with interferon (IFN)-γ, which is the cytokine crucial for controlling the parasites’ replication. Using genome-wide transcriptome analysis we show herein that infection with T. gondii leads to global unresponsiveness of murine macrophages to IFN-γ. More than 61% and 89% of the transcripts, which were induced or repressed by IFN-γ in non-infected MΦ, respectively, were not altered after stimulation of T. gondii-infected cells with IFN-γ. These genes are involved in a variety of biological processes, which are mostly but not exclusively related to immune responses. Analyses of the underlying mechanisms revealed that IFN-γ-triggered nuclear translocation of STAT1 still occurred in Toxoplasma-infected MΦ. However, STAT1 bound aberrantly to oligonucleotides containing the IFN-γ-responsive gamma-activated site (GAS) consensus sequence. Conversely, IFN-γ did not induce formation of active GAS-STAT1 complexes in nuclear extracts from infected MΦ. Mass spectrometry of protein complexes bound to GAS oligonucleotides showed that T. gondii-infected MΦ are unable to recruit non-muscle actin to IFN-γ-responsive DNA sequences, which appeared to be independent of stimulation with IFN-γ and of STAT1 binding. IFN-γ-induced recruitment of BRG-1 and acetylation of core histones at the IFN-γ-regulated CIITA promoter IV, but not β-actin was diminished by >90% in Toxoplasma-infected MΦ as compared to non-infected control cells. Remarkably, treatment with histone deacetylase inhibitors restored the ability of infected macrophages to express the IFN-γ regulated genes H2-A/E and CIITA. Taken together, these results indicate that Toxoplasma-infected MΦ are unable to respond to IFN-γ due to disturbed chromatin remodelling, but can be rescued using histone deacetylase inhibitors. Comparison of 4 different RNA pools with a 2-Color-Loop Design including 10 microarrays: [1] T. gondii infected and IFN-gamma treated, [2] T. gondii infected and untreated, [3] Non-infected and IFN-gamma treated, and [4] Non-infected and untreated.
2012-01-25 | E-GEOD-28499 | biostudies-arrayexpress
Project description:Intracellular pathogens including the apicomplexan and opportunistic parasite Toxoplasma gondii profoundly modify their host cells in order to establish infection. We have shown previously that intracellular T. gondii inhibit up-regulation of regulatory and effector functions in murine macrophages (MΦ) stimulated with interferon (IFN)-γ, which is the cytokine crucial for controlling the parasites’ replication. Using genome-wide transcriptome analysis we show herein that infection with T. gondii leads to global unresponsiveness of murine macrophages to IFN-γ. More than 61% and 89% of the transcripts, which were induced or repressed by IFN-γ in non-infected MΦ, respectively, were not altered after stimulation of T. gondii-infected cells with IFN-γ. These genes are involved in a variety of biological processes, which are mostly but not exclusively related to immune responses. Analyses of the underlying mechanisms revealed that IFN-γ-triggered nuclear translocation of STAT1 still occurred in Toxoplasma-infected MΦ. However, STAT1 bound aberrantly to oligonucleotides containing the IFN-γ-responsive gamma-activated site (GAS) consensus sequence. Conversely, IFN-γ did not induce formation of active GAS-STAT1 complexes in nuclear extracts from infected MΦ. Mass spectrometry of protein complexes bound to GAS oligonucleotides showed that T. gondii-infected MΦ are unable to recruit non-muscle actin to IFN-γ-responsive DNA sequences, which appeared to be independent of stimulation with IFN-γ and of STAT1 binding. IFN-γ-induced recruitment of BRG-1 and acetylation of core histones at the IFN-γ-regulated CIITA promoter IV, but not β-actin was diminished by >90% in Toxoplasma-infected MΦ as compared to non-infected control cells. Remarkably, treatment with histone deacetylase inhibitors restored the ability of infected macrophages to express the IFN-γ regulated genes H2-A/E and CIITA. Taken together, these results indicate that Toxoplasma-infected MΦ are unable to respond to IFN-γ due to disturbed chromatin remodelling, but can be rescued using histone deacetylase inhibitors.
2012-01-25 | GSE28499 | GEO
Project description:Type-I (e.g. IFN-alpha, IFN-beta) and type-II IFNs (IFN-gamma) have antiviral, antiproliferative, and immunomodulatory properties. Both types of IFN signal through the Jak/STAT pathway to elicit antiviral activity, yet IFN-gamma is thought to do so only through STAT1 homodimers while type-I IFNs activate both STAT1- and STAT2-containing complexes such as ISGF3. Here we show that ISGF3II - composed of phosphorylated STAT1, unphosphorylated STAT2, and IRF9 - also plays a role in IFN-gamma-mediated antiviral activity in humans. Using phosphorylated STAT1 as a marker for IFN signaling, western blot analysis of IFN-alpha2a treated human A549 cells revealed that pSTAT1 (Y701) levels peaked at 1h, decreased by 6h, and remained at low levels for up to 48h. Cells treated with IFN-gamma showed a biphasic pSTAT1 response with an early peak at 1-2h and a second peak at 15-24h. Gene expression microarray following IFN-gamma treatment for 24h indicated an induction of antiviral genes that are induced by ISGF3 and associated with a type-1 IFN response. Induction of these genes by autocrine type-I and type-III IFN signaling was ruled out using neutralizing antibodies to these IFNs in biological assays and by qRT-PCR. Despite the absence of autocrine IFNs, IFN-gamma treatment induced formation of ISGF3II. This novel transcription factor complex binds to ISRE promoter sequences, as shown by ChIP analysis of the PKR promoter. STAT2 and IRF9 knockdown in A549 cells reversed IFN-gamma-mediated ISRE induction and antiviral activity - implicating ISGF3II formation as a significant component of the cellular response and biological activity of IFN-gamma. Two treatments using three biological replicates each were performed using three million A549 cells. Each was seeded overnight in 10mL complete RPMI and treated. Three were treated with alpha-IFN and three treated with gamma-IFN for 24h. Control samples were left untreated.
2011-01-19 | E-GEOD-25113 | biostudies-arrayexpress
Project description:We investigated the roles of IRF-3 and IRF-7 in innate antiviral immunity against dengue virus (DENV). Double-deficient Irf-3-/-7-/- mice infected with the DENV2 strain S221 possessed 1,000-150,000 fold higher levels of viral RNA than wild-type and single-deficient mice 24 hours after infection; however, they remained resistant to lethal infection. IFN-α/β was induced similarly in wild-type and Irf-3-/- mice post DENV infection, whereas in the Irf-7-/- and Irf-3-/-7-/- mice, significantly low levels of IFN-α/β expression was observed within 24 hours post-infection. IFN-stimulated gene (ISG) induction was also delayed in Irf-3-/-7-/- mice relative to wild-type and single-deficient mice. In particular, Cxcl10 and Ifnα2 were rapidly induced independently of both IRF-3 and IRF-7 in the Irf-3-/-7-/- mice with DENV infection. Higher levels of serum IFN-γ, IL-6, CXCL10, IL-8, IL-12 p70, and TNF were also observed in Irf-3-/-7-/- mice 24 hours after infection, at which time point viral titers peaked and started to be cleared. Antibody-mediated blockade experiments revealed that IFN-γ, CXCL10, and CXCR3 function to restrict DENV replication in Irf-3-/-7-/- mice. Additionally, the ISGs Cxcl10, Ifit1, Ifit3, and Mx2 can be induced via an IRF-3- and IRF-7-independent pathway that does not involve IFN-γ signaling for protection against DENV. Collectively, these results demonstrate that IRF-3 and IRF-7 are redundant, albeit IRF-7 plays a more important role than IRF-3 in inducing the initial IFN-α/β response; only the combined actions of IRF-3 and IRF-7 are necessary for efficient control of early DENV infection; and the late, IRF-3- and IRF-7-independent pathway contributes to anti-DENV immunity. To identify the antiviral genes that are controlled by IRF-3 and IRF-7 signaling during DENV infection, we examined a panel of ISG expression in the spleens of wild-type, Irf-3-/-, Irf-7-/- and Irf-3-/-7-/- mice at 12 or 24 hours after DENV infection using a quantitative PCR array kit. The fold changes in expression of 55 genes from infected mice were normalized to that of strain-matched naïve mice.
2013-08-15 | E-GEOD-49871 | biostudies-arrayexpress
Project description:BRD9 was identified in a genome-wide screen for genes regulating the response to interferon (IFN) in a A549 based reporter cell line. Subsequent experiments determined an involvement of BRD9 in the transcriptional regulation of Interferon-stimulated genes (ISGs) expression following stimulation with IFN-a2. The aim of this proximity-labelling experiments was to gain a more mechanistic understanding of BRD9 recruitment during the IFN signal transduction using A549 cells stably transduced with BRD9-TurboID and mCherry-TurboID fusion proteins. The BRD9 interactome in the absence of IFN- a2 was determined. We found that following IFN-a2 treatment, STAT2 significantly associates with BRD9-TurboID.
2021-08-17 | PXD026926 | Pride
Project description:Type I Interferons (IFN-I) mediate cellular responses to virus infection. IFN-I induce IFN stimulated gene (ISG) expression by phosphorylating STAT1 and STAT2, and together with interferon regulatory factor (IRF)9, form the transcription complex ISGF3 that binds to the interferon-stimulated response element (ISRE) in ISG promoters. As a component of ISGF3 it is clear that STAT2 plays an essential role in the transcriptional responses to IFN-I with a strong dependence on STAT1. Previously, we showed that STAT2 also forms homodimers that interact with IRF9 (STAT2-IRF9) to activate transcription of ISRE containing ISGs in response to IFN-I. Indeed, evidence is accumulating for the existence of a STAT1-independent IFN-I signaling pathway, where STAT2-IRF9 can substitute the role of ISGF3. Here, we provide further insight in the transcriptional regulation and the biological implications of STAT2-IRF9 dependent IFN-I signaling. In human STAT1 KO cells overexpressing human STAT2 (U3C-STAT2) we observed that in response to IFN-I STAT2 homodimers interact with IRF9 to regulate ISG transcription. The IFN-I-induced phosphorylation profile of STAT2 in U3C-STAT2 was prolonged as compared to WT cells (2fTGH), which corresponded with the expression pattern of OAS2 that also depended on IRF9. Subsequent microarray analysis of IFN-I treated 2fTGH and U3C-STAT2 extended our initial observations and identified more than 60 known antiviral ISGs commonly up-regulated in both cell types. The expression profile of these ISGs was delayed and prolonged in U3C-STAT2 as opposed to the early and transient response in 2fTGH. Moreover, U3C-STAT2 were able to restore an antiviral response upon EMCV and VSV infection that was comparable to the response in 2fTGH. Together, our results strongly suggest that an alternative IFN-I-mediated, STAT2-IRF9 dependent signaling pathway exists that can generate an antiviral response without STAT1 and could be beneficial for example against viruses that directly block STAT1 and impair the formation of ISGF3.
2015-09-10 | GSE48313 | GEO
Project description:Interferon-regulatory factors (IRFs) are a family of transcription factors (TFs) that play critical roles in translating viral recognition into antiviral responses, including type I IFN production. Dengue virus (DENV) and other clinically important flaviviruses are controlled by functional type I interferon (IFN) responses. Using an experimental model of DENV infection that recapitulates key aspects of the human disease in mice, we demonstrate that while mice lacking the type I IFN receptor (Ifnar1-/-) succumb to DENV infection, mice that are deficient in IRF-3, IRF-5, and IRF-7 – the three transcription factors thought to regulate type I IFN production – survive DENV challenge. Genome-wide RNA-seq analysis of WT, Irf3(-/-)×Irf7(-/-) (DKO), Irf3-/-xIrf5-/-xIrf7-/- (TKO), and Ifnar1-/- (AB6) splenocytes identified minimal type I IFN production but a robust type II IFN (IFN-γ) response in DKO and TKO mice later shown to be dependent on IRF-1. These results reveal a key role for IRF-1 in antiviral defense by activating both type I and II IFN responses during DENV infection.
2017-11-07 | GSE104189 | GEO
Project description:Pre-infection with Toxoplasma parasites inhibits induction of an interferon gamma responsive gene expression program. In this study we aimed to determine what role host negative regulatory proteins that are induced by Toxoplasma infection, such as SOCS-1, have in this inhibition. We used Affymetrix microarrays to analyze host cell transcription after pre-treatment with the protein synthesis inhibitor cyclohexamide (CHX), Toxoplasma infection, and subsequent interferon-gamma stimulation. Human foreskin fibroblasts (HFFs) were left untreated or treated with CHX for 40min. Cells were infected, or not, with type I (RH) Toxoplasma parasites, for one hour, and subsequently stimulated with human IFN-γ for one hour. Total RNA was isolated and hybridized to Affymetrix Human U133A 2.0 gene chips.
2015-08-01 | E-GEOD-34916 | biostudies-arrayexpress
Project description:Toxoplasma strains are known to inhibit the expression of several interferon-gamma induced genes, and a type II strain was shown to dysregulate genome-wide responses to interferon-gamma in human fibroblasts (Kim et al., 2007, J Immunol.). In this study we aimed to determine the effect of infection with three clonal lineages of Toxoplasma, type I, II, and III strains on genome-wide interferon-gamma induced transcription in murine macrophages. We also assessed the effect of the two main Toxoplasma modulators of mouse macrophage transcription, ROP16 and GRA15 (Jensen et al., 2011, Cell Host Microbe). We used Affymetrix microarrays to analyze host cell transcription after Toxoplasma infection and interferon-gamma stimulation. RAW264.7 murine macrophages were left uninfected or infected with type I (RH), type I ?rop16 (RH ?rop16), type II (Pru), type II ?gra15 (Pru ?gra15), or type II (CEP) parasites at an MOI ~5 for 18 hours and subsequently stimulated with murine IFN-? for six hours. Plaque assays were done to assess parasite viability. Total RNA was isolated and hybridized to Affymetrix Mouse 430A 2.0 gene chips.
2013-02-19 | E-GEOD-34913 | biostudies-arrayexpress