Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA139297 | ENA |
REPOSITORIES: ENA
Similar Datasets
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:The protozoan parasite Toxoplasma gondii is a highly successful intracellular pathogen, owing in part to its ability to subvert the host immune system. In particular, parasite infection suppresses STAT1 signaling in a variety of cell types, including IFN-γ activated macrophages, via a block within the nucleus. A high-throughput screen to identify genes able to overcome parasite-mediated suppression of STAT1 activity identified 9 transcription factors as enhancers of STAT1 signaling in T. gondii infected cells, including the orphan nuclear hormone receptor TLX. Expression profiling revealed that TLX is a transcriptional regulator that drives the steady-state expression of STAT1-independent genes involved brain function and development, while enhancing the output of a subset of IFN-γ-dependent target genes. Infection of TLX deficient mice with Toxoplasma results in impaired production of interleukin-12 by dendritic cells and increased parasite burden in the brain during chronic infection. These results demonstrate a previously unrecognized function for this orphan nuclear hormone receptor in regulating STAT1 signaling and host defense, and reveal that STAT1 activity can be modulated in a context-specific manner by such ‘modifiers’.
2015-05-29 | GSE55750 | GEO
Project description:The protozoan parasite Toxoplasma gondii is a highly successful intracellular pathogen, owing in part to its ability to subvert the host immune system. In particular, parasite infection suppresses STAT1 signaling in a variety of cell types, including IFN-γ activated macrophages, via a block within the nucleus. A high-throughput screen to identify genes able to overcome parasite-mediated suppression of STAT1 activity identified 9 transcription factors as enhancers of STAT1 signaling in T. gondii infected cells, including the orphan nuclear hormone receptor TLX. Expression profiling revealed that TLX is a transcriptional regulator that drives the steady-state expression of STAT1-independent genes involved brain function and development, while enhancing the output of a subset of IFN-γ-dependent target genes. Infection of TLX deficient mice with Toxoplasma results in impaired production of interleukin-12 by dendritic cells and increased parasite burden in the brain during chronic infection. These results demonstrate a previously unrecognized function for this orphan nuclear hormone receptor in regulating STAT1 signaling and host defense, and reveal that STAT1 activity can be modulated in a context-specific manner by such ‘modifiers’.
2015-05-29 | GSE55749 | GEO
Project description:This is an experiment designed on exploring human protein complexes interacted with a virulence protein TgIST secreted from Toxoplasma gondii. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was performed on TgIST IP samples from human cells U3A or U3A-STAT1, treated with IFN-gamma. Served as the Supplementary Data for Fig 1b and Fig 1c.
2022-06-12 | MSV000089636 | MassIVE
Project description:An early hallmark of Toxoplasma gondii infection is the rapid control of the parasite population by a potent multifaceted innate immune response that engages resident and homing immune cells along with pro- and counter-inflammatory cytokines. In this context, IFN-γ activates a variety of T. gondii-targeting activities in immune and nonimmune cells but can also contribute to host immune pathology. T. gondii has evolved mechanisms to timely counteract the host IFN-γ defenses by interfering with the transcription of IFN-γ-stimulated genes. We now have identified TgIST (T. gondii inhibitor of STAT1 transcriptional activity) as a critical molecular switch that is secreted by intracellular parasites and traffics to the host cell nucleus where it inhibits STAT1-dependent proinflammatory gene expression. We show that TgIST not only sequesters STAT1 on dedicated loci but also promotes shaping of a nonpermissive chromatin through its capacity to recruit the nucleosome remodeling deacetylase (NuRD) transcriptional repressor. We found that during mice acute infection, TgIST-deficient parasites are rapidly eliminated by the homing Gr1+ inflammatory monocytes, thus highlighting the protective role of TgIST against IFN-γ-mediated killing. By uncovering TgIST functions, this study brings novel evidence on how T. gondii has devised a molecular weapon of choice to take control over a ubiquitous immune gene expression mechanism in metazoans, as a way to promote long-term parasitism.
2016-07-18 | GSE81613 | GEO
Project description:The local production of IFN-γ is important to control Toxoplasma gondii in the brain but the basis for these protective effects are not fully understood. The studies presented here reveal that the ability of IFN-γ to inhibit parasite replication in astrocytes in vitro is dependent on signal transducer and activator of transcription 1 (STAT1) and that mice that specifically lack STAT1 in astrocytes are unable to limit parasite replication in the central nervous system (CNS). This susceptibility is associated with a loss of anti-microbial pathways but also altered local immune responses that include decreased T cell production of IFN-γ and elevated expression of inhibitory receptors. These results identify a critical role for astrocytes in limiting the replication of an important opportunistic pathogen and highlight their role in coordinating local anti-parasitic responses.
2016-10-20 | GSE67137 | GEO
Project description:Toxoplasma gondii is a ubiquitous apicomplexan parasite of mammals and birds and an important pathogen of humans. IFN-g is the major mediator of host resistance against T. gondii but intriguingly, parasite-infected host cells including macrophages are severely impaired to respond to IFN-g due to defective transcriptional activation of target genes. Here, we tested the possibility that the impaired responsiveness of T. gondii-infected macrophages to IFN-g can be restored by inhibiting histone deacetylases (HDACs) using the class I-specific inhibitor MS-275. Treatment of RAW264.7 cells with MS-275 indeed increased MHC class II surface expression in infected and non-infected cells and largely abolished the inhibition of IFN-g-regulated MHC class II expression exerted by T. gondii. Genome-wide transcriptome profiling revealed that MS-275 increased mean mRNA levels of IFN-g-regulated genes particularly in non-infected macrophages. Transcript levels of 33% of IFN-g secondary response genes but only those of a few primary response genes were also increased by MS-275 in T. gondii-infected cells. Importantly, the unresponsiveness of parasite-infected cells to IFN-g was however not abolished by MS-275. Furthermore, MS-275 also up-regulated several anti-inflammatory cytokines or signaling molecules in T. gondii-infected macrophages. It additionally regulated expression of more than 2500 genes in non-infected macrophages expression of which was surprisingly counteracted by prior infection with T. gondii. FACS analysis and immunofluorescence microscopy revealed that MS-275 did not considerably diminish the number of parasite-positive cells or the intracellular replication in macrophages stimulated or not with IFN-g. Thus, a supportive therapy using MS-275 appears inappropriate for treatment of toxoplasmosis.
2017-02-10 | GSE90478 | GEO
Project description:TgIST is an effector secreted by Toxoplasma gondii into the host cell that translocates to the nucleus and block STAT1 mediated transcription. STAT1 is involved in type I and II interferon (IFN) mediated upregulation of range of anti-parasitic molecules. A total of 544,234,059 read sequences generated from 3 independent biological replicates were mapped to human hg19 reference genome. Type I IFN activation of HFFs infected with TgIST knockout parasites showed upregulation of genes involved in interferon signaling compared to wild type parasites.
2019-06-30 | GSE125066 | GEO
Project description:Infection with the parasite Toxoplasma gondii leads to production of interferon gamma (IFN) that stimulates cells to upregulate defence proteins targeting the parasite for cell intrinsic elimination or growth restriction. Various host defence mechanisms operate at the parasitophorous vacuole (PV) in different human cell types leading to PV disruption, acidification, or membrane envelopment. Ubiquitin and p62 are players in all human host control mechanisms of Toxoplasma, but other unifying proteins have not been identified. Here, we show that p97/valosin-containing protein (VCP), as well as its associated proteins ANKRD13A and UBXD1 control Toxoplasma infection while recruited to the PV in IFN-stimulated endothelial cells. Convergent deposition of ANKRD13A, p97/VCP and UBXD1 onto the same vacuole is dependent on vacuolar ubiquitination and observed within 2h post-infection. ANKRD13A, p97/VCP and UBXD1 all drive the acidification mechanism of the vacuole, which is the IFN-dependent control pathway of Toxoplasma in endothelial cells. We assessed p97/VCP in Toxoplasma control in various human cells and demonstrate that p97/VCP is a universal IFN-dependent host restriction factor targeting the Toxoplasma PV in epithelial (HeLa) and endothelial cells (HUVEC), fibroblasts (HFF) and macrophages (THP1).
2023-11-15 | PXD042937 | Pride