Listeria monocytogenes induces T cell receptor unresponsiveness via its pore-forming toxin listeriolysin O
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE19337 | GEO | 2010/06/29
SECONDARY ACCESSION(S): PRJNA121707
REPOSITORIES: GEO
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Project description:The success of many pathogens relies on their ability to circumvent the innate and adaptive immune defenses. How bacterial pathogens subvert host responses is not clear. Cholesterol-dependent cytolysins (CDCs) represent an expansive family of homologous pore-forming toxins produced by more than 20 Gram-positive bacterial species. Here we show that listeriolysin O (LLO), a prototype CDC produced by Listeria monocytogenes, inhibits antigen receptor-induced T cell proliferation. In vivo proliferation of OT II T cells was highly diminished in the presence of wild type but not the LLO-deficient bacteria. T cells pre-exposed to LLO ex vivo were also impaired in proliferation upon TCR activation in vivo and in vitro. Our results suggest that LLO-induced T cell unresponsiveness is due to the sub-threshold activation of T cells via the induction of a calcium-NFAT dependent transcriptional program that drives the expression of negative regulators of TCR signaling. Keywords: Listerilysin O, Ionomycin, 3 hours stimulation Pooled primary CD4+ T cells isolated from spleen and mesenteric lymph nodes were incubated in either control (Ctrl) medium or medium containing 0.25 ug/ml listeriolysin O (LLO) or 1 uM Ionomycin (Iono) for 3 hours. Thereafter, cells were washed and RNA was prepared.
2010-07-29 | E-GEOD-19337 | biostudies-arrayexpress
Project description:Upon infection, pathogens reprogram host gene expression. In eukaryotic cells, genetic reprogramming is induced by the concerted activation/repression of transcription factors and various histone modifications that control DNA accessibility in chromatin. We report here that the bacterial pathogen, Listeria monocytogenes, induces a dramatic dephosphorylation of histone H3 as well as a deacetylation of histone H4 during early phases of infection. This effect is mediated by the major listerial toxin listeriolysin (LLO), in a pore forming independent manner. Strikingly, a similar effect is also observed with other toxins of the same family, such as Clostridium perfringens perfringolysin (PFO) and Streptococcus pneumoniae pneumolysin (PLY). The decreased levels of histone modifications correlate with a reduced transcriptional activity of a subset of host genes, including key immunity genes. Thus, manipulation of the epigenetic information emerges here as an unsuspected function shared by several bacterial toxins, highlighting a common strategy used by intracellular and extracellular pathogens to modulate the host response early during infection.
2008-04-01 | E-MEXP-1078 | biostudies-arrayexpress
Project description:Generating antitumor immune responses requires the phagocytosis of tumor cells and subsequent cross-presentation of tumor-derived antigens by antigen-presenting cells. However, these processes are impeded by phagocytosis checkpoints and inefficient cytosolic transport of antigenic peptides from phagolysosomes. Here, using a microbial-inspired strategy, we engineered an antibody-drug conjugate (ADC) that targets the “don’t eat me” signal CD47 linked to the bacterial toxin listeriolysin O from the intracellular bacterium Listeria monocytogenes via a cleavable linker (CD47-LLO). CD47-LLO promotes the phagocytosis of cancer cells followed by the release and activation of LLO to form pores on phagolysosomal membranes that allow cytosolic entry of tumor-derived contents, leading to enhanced antigen cross-presentation of tumor-derived peptides and activation of cytosolic immune sensors. CD47-LLO treatment in vivo significantly inhibited the growth of both localized and metastatic tumors and improved animal survival as monotherapy or in combination with checkpoint blockade. Together, these results demonstrate that designing ADCs to promote immune recognition of tumor cells represents a promising therapeutic strategy for treating multiple cancers.
2024-12-01 | GSE255937 | GEO
Project description:Bacterial pathogens use various strategies to interfere with host cell functions. Among these strategies, bacteria induce transcriptional changes, in order to modify the set of proteins synthetized by the host cell, or target pre-existing proteins by modulating their post-translational modifications or by triggering their degradation. Protein levels variations in host cells during infection integrates both transcriptional and post-transcriptional regulations induced by pathogens. Here, we focused on host proteome alterations induced by the bacterial pathogen Listeria monocytogenes, and more specifically the Listeria toxin Listeriolysin O (LLO). In order to characterize host proteome alterations induced by LLO, we performed a shotgun proteomics analysis on HeLa cells treated or not with the LLO toxin. To this end, we used SILAC labelling (stable isotope labelling by amino acids in cell culture) to compared in a quantitative manner the protein content from two differentially treated cell populations: one control population and one population incubated with a sublytic dose of LLO (3 nM). We decided to expose cells to LLO during only 20 min to limit protein level changes resulting from transcriptional changes. We performed two independent experiments (experiment #1 and experiment #2) with swapped SILAC labelling to rule out putative labelling-dependent effects. A total of 2009 and 2577 proteins was quantified in each independent experiment, respectively, and 1834 proteins were quantified in both experiments. Among these 1834 proteins, we identified a total of 151 proteins for which protein levels were consistently decreased in cells treated with LLO (i.e. with a log2 control/LLO ratio >0.5 in both experiments). To assess whether the host proteasome was involved in the decrease of these 151 proteins, we repeated our proteomics analysis on SILAC-labelled HeLa cells pre-treated with proteasome inhibitors before exposure to LLO. Two independent experiments were similarly performed with swapped SILAC labelling (experiment #3 and experiment #4). Interestingly, we observed that the vast majority of host proteins identified as strongly downregulated in response to LLO also displayed significant decreased levels in the presence of proteasome inhibitors, indicating that the majority of observed decreases in host protein levels induced by LLO are not due to proteasome-mediated degradation. In follow-up experiments, we validated that LLO decreases in particular the protein level of two E2 ubiquitin enzymes, UBE2K and UBE2N, leading to major changes in the host ubiquitylome. This toxin-induced proteome remodeling involves post-transcriptional regulations, as no modification in the transcription levels of the corresponding genes was observed. These decreases in host protein levels were observed in different epithelial cell lines but not in macrophages. In addition, we could show that Perfringolysin O, another bacterial pore-forming toxin similar to LLO, also induces host proteome changes. Taken together, our data show that different bacterial pore-forming toxins induce deep proteome remodeling, that may impair host epithelial cell functions.
2018-11-07 | PXD006996 | Pride
Project description:Bacterial pathogens use various strategies to interfere with host cell functions. Among these strategies, bacteria induce transcriptional changes, in order to modify the set of proteins synthetized by the host cell, or target pre-existing proteins by modulating their post-translational modifications or by triggering their degradation. Protein levels variations in host cells during infection integrates both transcriptional and post-transcriptional regulations induced by pathogens. Here, we focused on host proteome alterations induced by the bacterial pathogen Listeria monocytogenes, and more specifically the Listeria toxin Listeriolysin O (LLO). In order to characterize host proteome alterations induced by LLO, we performed a shotgun proteomics analysis on HeLa cells treated or not with the LLO toxin. To this end, we used SILAC labelling (stable isotope labelling by amino acids in cell culture) to compared in a quantitative manner the protein content from two differentially treated cell populations: one control population and one population incubated with a sublytic dose of LLO (3 nM). We decided to expose cells to LLO during only 20 min to limit protein level changes resulting from transcriptional changes. We performed two independent experiments (experiment #1 and experiment #2) with swapped SILAC labelling to rule out putative labelling-dependent effects. A total of 2009 and 1684 proteins was quantified in each independent experiment, respectively, and 1360 proteins were quantified in both experiments. Among these 1360 proteins, we identified a total of 91 proteins for which protein levels were consistently decreased in cells treated with LLO (i.e. with a log2 control/LLO ratio >0.5 in both experiments). To assess whether the host proteasome was involved in the decrease of these 91 proteins, we repeated our proteomics analysis on SILAC-labelled HeLa cells pre-treated with proteasome inhibitors before exposure to LLO. Two independent experiments were similarly performed with swapped SILAC labelling (experiment #3 and experiment #4). Interestingly, we observed that the vast majority of host proteins identified as strongly downregulated in response to LLO also displayed significant decreased levels in the presence of proteasome inhibitors, indicating that the majority of observed decreases in host protein levels induced by LLO are not due to proteasome-mediated degradation. In follow-up experiments, we identified that LLO decreases in particular the protein level of two E2 ubiquitin enzymes, UBE2K and UBE2N, leading to major changes in the host ubiquitylome. This toxin-induced proteome remodeling involves post-transcriptional regulations, as no modification in the transcription levels of the corresponding genes was observed. These decreases in host protein levels were observed in different epithelial cell lines but not in macrophages. In addition, we could show that Perfringolysin O, another bacterial pore-forming toxin similar to LLO, also induces host proteome changes. Taken together, our data show that different bacterial pore-forming toxins induce deep proteome remodeling, that may impair host epithelial cell functions.
2018-11-07 | PXD006900 | Pride
Project description:Cerebral listeriosis is characterized by neuronal apoptosis and microglial cell activation, but little is known about the bacterial virulence factors involved in this process and how bacterial dissemination is controlled. Here, we show that the cellular target of Listeria monocytogenes (LM) in murine hippocampal cultures is microglia rather than neurons or other glial cells, which are rarely infected. This in vitro model served to demonstrate that infected microglial cells release a soluble factor to the medium responsible for neuronal apoptosis. We investigated the production of this factor in a well-established murine microglia cell model BV2 cells, and compared with J-774 macrophage cells after infection with different LM bacterial mutants. Our purpose was to study in both cell types parameters such as the listericidal capacities, pro-inflammatory cytokines released, and bacterial factors involved in the intracellular cycle. Our data reveal that microglia shows unique features to handle a LM infection. Microglia is three times more permissive for LM intracellular growth than murine macrophages; while producing five times higher levels of pro-inflammatory cytokines IL-6, MCP-1 and TNF-α than macrophages. Using different LM mutants (i.e., LMWT, LM∆LLO, LM∆ActA or LM∆plcB) we conclude that LLO and ActA are not involved in LM proliferation within microglia cells, while they are required for survival within macrophages. Moreover, ActA controls TNF-α production, a cytokine involved in neural apoptosis. Transcriptional differential response of microglia infected with different LM mutants reflected ActA controls the TNF-a signaling pathway through out molecules and chemokines involved in this pathway such as NFkβ, MAPK-1, Ccl2, Ccl3, Ccl4 and CxCl10. The project implies the analysis of two replicates from three different conditions, in total 6 samples: microglia cells non-infected, microglia cells infected with Listeria monocytogenes (LM) wild type (LLO+), microglia cells infected with LM deficient in listeriolysin O (LLO-) and microglia cells infected with LM deficient in ActA (1942). References samples were microglia cells non-infected (NT). Infection with LM was performed for 1 hour, followed by 24 hours in medium with antibiotics to avoid bacterial extracellular growth. Gene expression analysis was performed using Partek Genomics Suite software (version 6.11.0801; Partek). GeneChip data were filtered to remove those probe sets with an intensity raw value close to background levels. Probe sets for each array are pre-processed using RMA. Also, probe sets whose expression change under all experimental conditions was below a threshold, based on the standard desviation of the normalised intensity values, were filtered.
2011-10-02 | E-GEOD-32505 | biostudies-arrayexpress
Project description:Bacterial pathogens use various strategies to interfere with host cell functions. Among these strategies, bacteria induce transcriptional changes, in order to modify the set of proteins synthetized by the host cell, or target pre-existing proteins by modulating their post-translational modifications or by triggering their degradation. Protein levels variations in host cells during infection integrates both transcriptional and post-transcriptional regulations induced by pathogens. Here, we focused on host proteome alterations induced by the bacterial pathogen Listeria monocytogenes, and more specifically the Listeria toxin Listeriolysin O (LLO). In order to characterize host proteome alterations induced by LLO, we performed a shotgun proteomics analysis on HeLa cells treated or not with the LLO toxin. To this end, in a first analysis we used SILAC labelling (stable isotope labelling by amino acids in cell culture) to compare in a quantitative manner the protein content from two differentially treated cell populations: one control population and one population incubated with a sublytic dose of LLO (3 nM). We decided to expose cells to LLO during only 20 min to limit protein level changes resulting from transcriptional changes. We performed two independent experiments (experiment #1 and experiment #2) with swapped SILAC labelling to rule out putative labelling-dependent effects. A total of 2,009 and 2,577 proteins was quantified in each independent experiment, respectively, and 1,834 proteins were quantified in both experiments. Among these 1834 proteins, we identified a total of 151 proteins for which protein levels were consistently decreased in cells treated with LLO (i.e. with a log2 control/LLO ratio >0.5 in both experiments). In addition to this preliminary study, we carried out a second experiment using label-free quantitative shotgun proteomics to compare protein abundance in cells treated or not with LLO. Four independent biological replicates were included in this second screen in order to perform a robust statistical analyses of downregulated proteins. Among the 2,973 proteins that were quantified in all independent replicates, we identified a total of 149 proteins (5.0 %) for which protein levels were significantly decreased in cells treated with LLO. In contrast to these decreases, only 16 proteins (0.5 %) showed significant increased levels in LLO-treated cells. This result confirmed that LLO remodels the cell proteome mainly by decreasing the level of host targets. To assess whether the host proteasome was involved in the decrease of these 149 proteins, we repeated our label-free proteomics analysis on HeLa cells pre-treated with proteasome inhibitors before exposure to LLO. Interestingly, we observed that the vast majority (i.e. 83%) of host proteins identified as strongly downregulated in response to LLO also displayed significant decreased levels in the presence of proteasome inhibitors, indicating that the majority of observed decreases in host protein levels induced by LLO are not due to proteasome-mediated degradation. In follow-up experiments, we validated that LLO decreases in particular the protein level of two E2 ubiquitin enzymes, UBE2K and UBE2N, leading to major changes in the host ubiquitylome. This toxin-induced proteome remodeling involves post-transcriptional regulations, as no modification in the transcription levels of the corresponding genes was observed. These decreases in host protein levels were observed in different epithelial cell lines but not in macrophages. In addition, we could show that Perfringolysin O, another bacterial pore-forming toxin similar to LLO, also induces host proteome changes. Taken together, our data show that different bacterial pore-forming toxins induce deep proteome remodeling, that may impair host epithelial cell functions.
2018-05-17 | PXD009339 | Pride
Project description:Mitochondrial function adapts to cellular demands and is affected by the ability of the organelle to undergo fusion and fission in response to physiological and non-physiological cues. We previously showed that infection with the human bacterial pathogen Listeria monocytogenes elicits transient mitochondrial fission and a drop in mitochondrial -dependent energy production through a mechanism requiring the bacterial pore-forming toxin listeriolysin O (LLO). Here, we performed quantitative mitochondrial proteomics to search for host factors involved in L. monocytogenes-induced mitochondrial fission. We found that Mic10, a critical component of the mitochondrial contact site and cristae organizing system (MICOS) complex, is significantly enriched in mitochondria isolated from cells infected with wild-type but not with LLO-deficient L. monocytogenes. Increased mitochondrial Mic10 levels did not correlate with upregulated transcription, suggesting a post-transcriptional regulation. We showed that Mic10 is necessary for L. monocytogenes-induced mitochondrial network fragmentation, and that it contributes to L. monocytogenes cellular infection independently of MICOS proteins Mic13, Mic26 and Mic27. Together, L. monocytogenes infection allowed us to uncover a role for Mic10 in mitochondrial fission.
2020-02-17 | PXD014667 | Pride
Project description:Modulating gene expression in macrophages can be used to improve tissue regeneration and redirect tumor microenvironments (TME) toward positive therapeutic outcomes. We have developed Bacillus subtilis as an engineered endosymbiont (EES) that resides in the host cell cytoplasm and controls the fates of macrophages. Secretion of mammalian transcription factors (TFs) from B. subtilis that expresses listeriolysin O (LLO; allowing the EES to escape destruction by the macrophage) modulated expression of surface markers, cytokines and chemokines indicating functional changes in a macrophage/monocyte cell line. The engineered B. subtilis LLO TF strains were evaluated in murine bone marrow-derived macrophages (BMDMs) by flow cytometry, chemokine/cytokine profiling, metabolic assays and RNA-Seq. Secretion of TFs by the EES shifted BMDM gene expression, production of cytokine and chemokines and metabolic patterns indicating that the TF strains could guide primary macrophage function. Therefore, the ability of the TF strains to alter the TME was characterized in vivo, in a murine 4T1 orthotopic breast cancer model to assess therapeutic effects. The TF strains altered the TME by shifting immune cell composition and attenuating tumor growth. Additionally, multiple doses of the TF strains were well tolerated by the mice. The use of B. subtilis LLO TF strains as EES showed promise as a unique therapeutic approach for cancer immunotherapy. The uses of EES could be expanded to modulate other mammalian cells over a range of biomedical applications.
2023-09-03 | GSE239519 | GEO
Project description:These studies utilized two TCR transgenic mouse lines, LLO118 and LLO56, that our laboratory has developed and characterized, which recognize the same Listeria monocytogenes LLO/IO-Ab epitope with equal affinities. When 104 naive CD4+ LLO T cells are transferred into a B6 mouse and one day later infected with wild type Listeria monocytogenes, the LLO118 T cells have a more robust primary expansion than LLO56. In contrast, after a secondary challenge, LLO56 T cells have a much greater expansion than LLO118 T cells. One striking phenotypic difference between the LLO118 and LLO56 T cells lies in their CD5 expression. CD5 expression has been shown to correlate directly with TCR affinity for self-pMHC and tonic signaling. LLO56 cells have a higher basal phosphorylation of the TCR chain, and they have significantly increased expression of Nur77 mRNA. These transcriptional profiling experiments examined if there were transcriptional differences between LLO118 and LLO56 T cells, either naive or after D7 of infection, that would account for their disparate in vivo behaviors.
2020-02-28 | GSE146069 | GEO