A bacterial YopJ-family acetyltransferasesuppresseshost immune response by Nε-acetylation of JAK1
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE316818 | GEO | 2026/01/16
REPOSITORIES: GEO
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Project description:The intracellular bacterial pathogen Legionella pneumophila causes an inflammatory pneumonia called Legionnaires’ Disease. For virulence, L. pneumophila requires a Dot/Icm type IV secretion system that translocates bacterial effectors to the host cytosol. L. pneumophila lacking the Dot/Icm system is recognized by Toll-like receptors (TLRs), leading to a canonical NF-κB-dependent transcriptional response. In addition, L. pneumophila expressing a functional Dot/Icm system potently induces unique transcriptional targets, including proinflammatory genes such as Il23a and Csf2. Here we demonstrate that this Dot/Icm-dependent response, which we term the effector-triggered response (ETR), requires five translocated bacterial effectors that inhibit host protein synthesis. Upon infection of macrophages with virulent L. pneumophila, these five effectors caused a global decrease in host translation, thereby preventing synthesis of IκB, an inhibitor of the NF-κB transcription factor. Thus, macrophages infected with wildtype L. pneumophila exhibited prolonged activation of NF-κB, which was associated with transcription of ETR target genes such as Il23a and Csf2. L. pneumophila mutants lacking the five effectors still activated TLRs and NF-κB, but because the mutants permitted normal IκB synthesis, NF-κB activation was more transient and was not sufficient to fully induce the ETR. L. pneumophila mutants expressing enzymatically inactive effectors were also unable to fully induce the ETR, whereas multiple compounds or bacterial toxins that inhibit host protein synthesis via distinct mechanisms recapitulated the ETR when administered with TLR ligands. Previous studies have demonstrated that the host response to bacterial infection is induced primarily by specific microbial molecules that activate TLRs or cytosolic pattern recognition receptors. Our results add to this model by providing a striking illustration of how the host immune response to a virulent pathogen can also be shaped by pathogen-encoded activities, such as inhibition of host protein synthesis.
2011-01-08 | GSE26490 | GEO
Project description:The intracellular bacterial pathogen Legionella pneumophila causes an inflammatory pneumonia called Legionnaires’ Disease. For virulence, L. pneumophila requires a Dot/Icm type IV secretion system that translocates bacterial effectors to the host cytosol. L. pneumophila lacking the Dot/Icm system is recognized by Toll-like receptors (TLRs), leading to a canonical NF-κB-dependent transcriptional response. In addition, L. pneumophila expressing a functional Dot/Icm system potently induces unique transcriptional targets, including proinflammatory genes such as Il23a and Csf2. Here we demonstrate that this Dot/Icm-dependent response, which we term the effector-triggered response (ETR), requires five translocated bacterial effectors that inhibit host protein synthesis. Upon infection of macrophages with virulent L. pneumophila, these five effectors caused a global decrease in host translation, thereby preventing synthesis of IκB, an inhibitor of the NF-κB transcription factor. Thus, macrophages infected with wildtype L. pneumophila exhibited prolonged activation of NF-κB, which was associated with transcription of ETR target genes such as Il23a and Csf2. L. pneumophila mutants lacking the five effectors still activated TLRs and NF-κB, but because the mutants permitted normal IκB synthesis, NF-κB activation was more transient and was not sufficient to fully induce the ETR. L. pneumophila mutants expressing enzymatically inactive effectors were also unable to fully induce the ETR, whereas multiple compounds or bacterial toxins that inhibit host protein synthesis via distinct mechanisms recapitulated the ETR when administered with TLR ligands. Previous studies have demonstrated that the host response to bacterial infection is induced primarily by specific microbial molecules that activate TLRs or cytosolic pattern recognition receptors. Our results add to this model by providing a striking illustration of how the host immune response to a virulent pathogen can also be shaped by pathogen-encoded activities, such as inhibition of host protein synthesis.
2011-01-08 | GSE26473 | GEO
Project description:The intracellular bacterial pathogen Legionella pneumophila causes an inflammatory pneumonia called Legionnaires’ Disease. For virulence, L. pneumophila requires a Dot/Icm type IV secretion system that translocates bacterial effectors to the host cytosol. L. pneumophila lacking the Dot/Icm system is recognized by Toll-like receptors (TLRs), leading to a canonical NF-κB-dependent transcriptional response. In addition, L. pneumophila expressing a functional Dot/Icm system potently induces unique transcriptional targets, including proinflammatory genes such as Il23a and Csf2. Here we demonstrate that this Dot/Icm-dependent response, which we term the effector-triggered response (ETR), requires five translocated bacterial effectors that inhibit host protein synthesis. Upon infection of macrophages with virulent L. pneumophila, these five effectors caused a global decrease in host translation, thereby preventing synthesis of IκB, an inhibitor of the NF-κB transcription factor. Thus, macrophages infected with wildtype L. pneumophila exhibited prolonged activation of NF-κB, which was associated with transcription of ETR target genes such as Il23a and Csf2. L. pneumophila mutants lacking the five effectors still activated TLRs and NF-κB, but because the mutants permitted normal IκB synthesis, NF-κB activation was more transient and was not sufficient to fully induce the ETR. L. pneumophila mutants expressing enzymatically inactive effectors were also unable to fully induce the ETR, whereas multiple compounds or bacterial toxins that inhibit host protein synthesis via distinct mechanisms recapitulated the ETR when administered with TLR ligands. Previous studies have demonstrated that the host response to bacterial infection is induced primarily by specific microbial molecules that activate TLRs or cytosolic pattern recognition receptors. Our results add to this model by providing a striking illustration of how the host immune response to a virulent pathogen can also be shaped by pathogen-encoded activities, such as inhibition of host protein synthesis. Three-condition experiment: macrophages left uninfected (negative control), or infected with wildtype Legionella pneumophila, or the mutant Δ5, which lacks five bacterial effectors involved in inhibition of host protein synthesis (lgt1, lgt2, lgt3, sidI, sidL) (two experimental conditions). Biological replicates: two, independently infected, harvested, and hybridized to arrays. One technical replicate per array.
2011-01-08 | E-GEOD-26490 | biostudies-arrayexpress
Project description:The intracellular bacterial pathogen Legionella pneumophila causes an inflammatory pneumonia called Legionnaires’ Disease. For virulence, L. pneumophila requires a Dot/Icm type IV secretion system that translocates bacterial effectors to the host cytosol. L. pneumophila lacking the Dot/Icm system is recognized by Toll-like receptors (TLRs), leading to a canonical NF-κB-dependent transcriptional response. In addition, L. pneumophila expressing a functional Dot/Icm system potently induces unique transcriptional targets, including proinflammatory genes such as Il23a and Csf2. Here we demonstrate that this Dot/Icm-dependent response, which we term the effector-triggered response (ETR), requires five translocated bacterial effectors that inhibit host protein synthesis. Upon infection of macrophages with virulent L. pneumophila, these five effectors caused a global decrease in host translation, thereby preventing synthesis of IκB, an inhibitor of the NF-κB transcription factor. Thus, macrophages infected with wildtype L. pneumophila exhibited prolonged activation of NF-κB, which was associated with transcription of ETR target genes such as Il23a and Csf2. L. pneumophila mutants lacking the five effectors still activated TLRs and NF-κB, but because the mutants permitted normal IκB synthesis, NF-κB activation was more transient and was not sufficient to fully induce the ETR. L. pneumophila mutants expressing enzymatically inactive effectors were also unable to fully induce the ETR, whereas multiple compounds or bacterial toxins that inhibit host protein synthesis via distinct mechanisms recapitulated the ETR when administered with TLR ligands. Previous studies have demonstrated that the host response to bacterial infection is induced primarily by specific microbial molecules that activate TLRs or cytosolic pattern recognition receptors. Our results add to this model by providing a striking illustration of how the host immune response to a virulent pathogen can also be shaped by pathogen-encoded activities, such as inhibition of host protein synthesis. Four-condition experiment: macrophages left uninfected (negative control), or infected with wildtype Legionella pneumophila, the flagellin-deficient mutant ΔflaA, or the secretion-deficient mutant ΔdotA (three experimental conditions). Biological replicates: two, independently infected, harvested, and hybridized to arrays. One to two technical replicates per array, as indicated in file titles.
2011-01-08 | E-GEOD-26473 | biostudies-arrayexpress
Project description:Developing targeted therapy for cutaneous T cell lymphoma (CTCL) patients still requires actionable mutated genes and deregulated pathways to be identified. There is increasing evidence that activating mutations in JAK genes and deregulated JAK/STAT signaling are important mechanisms involved in multiple B and T cell malignancies, including CTCL. Therefore, in this study we focused on studying the mutational status of JAK1, JAK2 and JAK3 genes in a series of human CTCL lesions and cell lines using next-generation sequencing (NGS). We found that 7 of 48 (14.7%) of the analyzed cases harbored mutations in the JAK1 and JAK3 genes that mainly affected the pseudokinase domain of the corresponding proteins. On the basis of these results, we used a specific JAK inhibitor (INCB018424) in a series of CTCL cell lines with deregulated JAK/STAT activity. Treatment of CTCL cells with INCB018424 resulted in dose-dependent reduction of activated STAT expression, diminished cell viability, and increased apoptosis. We also studied global changes in gene expression in cells with mutated JAK1 and JAK3 proteins treated with INCB018424 and identified multiple genes that were differentially regulated by JAK/STAT signaling, such as FGF20 (upregulated) and EGR1 (downregulated). Thus, our results show that the detection of deregulated JAK/STAT signaling in CTCL lesions via JAK mutations or other surrogate markers may serve to indicate the clinical use of JAK/STAT inhibitors. 3 replicates of cells treated with DMSO or JAKi during 30 min and 3h
2015-10-31 | E-GEOD-68562 | biostudies-arrayexpress
Project description:Legionella pneumophila are important opportunistic pathogens for which environmental reservoirs such as protists are crucial for the infection of humans. Free-living amoebae are considered key hosts providing nutrients and shelter for highly efficient intracellular proliferation of L. pneumophila, which eventually leads to lysis of the amoeba host cell. Yet, the significance of other bacterial players for L. pneumophila ecology is poorly understood. In this study we used a ubiquitous amoeba and their bacterial endosymbiont to investigate the impact of this common association on L. pneumophila infection. We demonstrate that Acanthamoeba castellanii harboring the chlamydial symbiont Protochlamydia amoebophila were able to erase L. pneumophila and, in contrast to symbiont-free amoebae, survived the infection and were able to resume growth. Environmental amoeba isolates harboring P. amoebophila were equally well-protected, and fresh environmental isolates of L. pneumophila were equally well-erased, suggesting ecological relevance of this symbiont-mediated protection. We further show that protection was not mediated by impaired L. pneumophila uptake. Instead, we observed reduced virulence of L. pneumophila released from symbiont-containing amoebae that is strongly supported by transcriptome data. Interference with transition to the transmissive phase is thus likely the basis for this protection. Finally, our data indicate that the defensive response of amoebae harboring P. amoebophila leaves the amoebae with superior fitness reminiscent of immunological memory. Given that mutualistic associations between bacteria and amoebae are widely distributed, P. amoebophila and potentially other amoeba endosymbionts could be key elements in shaping environmental survival, abundance and virulence of this important pathogen thereby affecting frequency of human infection.
2019-04-14 | GSE125876 | GEO
Project description:Post-transcriptional processing and modification of messenger RNA (mRNA) regulates gene expression in eukaryotes by dictating the stability, localisation and translation of newly synthesised transcripts 1. These epitranscriptomic events are coordinated by an extensive network of RNA-binding proteins 2,3. Here we observed that the bacterial pathogen, Legionella pneumophila, caused the selective degradation of host cellular mRNAs encoding factors involved in glycolysis and related metabolic pathways. Screening of a library of L. pneumophila deletion mutant strains revealed a single effector protein, LegC4, that mediated the post-transcriptional degradation of host mRNAs encoding key glycolytic enzymes, thereby suppressing host glycolysis during infection. Using CLIP-seq and complementary methods, we observed that LegC4 bound to mature processed host mRNA recognising a guanine (G)-rich motif that was overrepresented within mRNAs targeted for degradation. In vitro activity assays showed that LegC4 harboured intrinsic RNase activity and structural determination of a catalytically inactive mutant of LegC4 in complex with single-stranded RNA revealed a unique RNA-binding domain 4. The selective binding and degradation of host mRNA by LegC4 reveals a previously undescribed mechanism of bacterial effector protein activity targeting the host epitranscriptome.
2024-11-10 | GSE281108 | GEO
Project description:Post-transcriptional processing and modification of messenger RNA (mRNA) regulates gene expression in eukaryotes by dictating the stability, localisation and translation of newly synthesised transcripts 1. These epitranscriptomic events are coordinated by an extensive network of RNA-binding proteins 2,3. Here we observed that the bacterial pathogen, Legionella pneumophila, caused the selective degradation of host cellular mRNAs encoding factors involved in glycolysis and related metabolic pathways. Screening of a library of L. pneumophila deletion mutant strains revealed a single effector protein, LegC4, that mediated the post-transcriptional degradation of host mRNAs encoding key glycolytic enzymes, thereby suppressing host glycolysis during infection. Using CLIP-seq and complementary methods, we observed that LegC4 bound to mature processed host mRNA recognising a guanine (G)-rich motif that was overrepresented within mRNAs targeted for degradation. In vitro activity assays showed that LegC4 harboured intrinsic RNase activity and structural determination of a catalytically inactive mutant of LegC4 in complex with single-stranded RNA revealed a unique RNA-binding domain 4. The selective binding and degradation of host mRNA by LegC4 reveals a previously undescribed mechanism of bacterial effector protein activity targeting the host epitranscriptome.
2024-11-09 | GSE280989 | GEO
Project description:Developing targeted therapy for cutaneous T cell lymphoma (CTCL) patients still requires actionable mutated genes and deregulated pathways to be identified. There is increasing evidence that activating mutations in JAK genes and deregulated JAK/STAT signaling are important mechanisms involved in multiple B and T cell malignancies, including CTCL. Therefore, in this study we focused on studying the mutational status of JAK1, JAK2 and JAK3 genes in a series of human CTCL lesions and cell lines using next-generation sequencing (NGS). We found that 7 of 48 (14.7%) of the analyzed cases harbored mutations in the JAK1 and JAK3 genes that mainly affected the pseudokinase domain of the corresponding proteins. On the basis of these results, we used a specific JAK inhibitor (INCB018424) in a series of CTCL cell lines with deregulated JAK/STAT activity. Treatment of CTCL cells with INCB018424 resulted in dose-dependent reduction of activated STAT expression, diminished cell viability, and increased apoptosis. We also studied global changes in gene expression in cells with mutated JAK1 and JAK3 proteins treated with INCB018424 and identified multiple genes that were differentially regulated by JAK/STAT signaling, such as FGF20 (upregulated) and EGR1 (downregulated). Thus, our results show that the detection of deregulated JAK/STAT signaling in CTCL lesions via JAK mutations or other surrogate markers may serve to indicate the clinical use of JAK/STAT inhibitors.
2015-10-31 | GSE68562 | GEO
Project description:Combined gene expression and DNA occupancy profiling identifies JAK/STAT signaling as a valid therapeutic target of t(8;21) AML t(8;21) is commonly associated with acute myeloid leukemia (AML). The resulting AML1-ETO fusion proteins are involved in the pathogenesis of AML. To identify novel molecular and therapeutic targets, we performed combined gene expression and promoter occupancy profiling using a primary leukemia initiating cell-enriched population induced by AML1-ETO9a (AE9a). CD45, a negative regulator of cytokine/growth factor receptor and JAK/STAT signaling, is greatly downregulated; furthermore JAK1 and JAK2 are upregulated in these leukemia cells. Consequently, JAK/STAT signaling is enhanced in the AE9a leukemia cells. Importantly, AE9a leukemia cells are highly susceptible to perturbation of JAK/STAT signaling, and a JAK2-selective inhibitor, TG101209, effectively targets these leukemia cells in vivo, suggesting the potential efficacy of JAK2 inhibitors in treating t(8;21) AML. Wild-type or AE9a leukemic samples in triplicate.
2012-09-04 | E-GEOD-15195 | biostudies-arrayexpress