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Park E, Jeon H, Lee N, Yu J, Park H, Satoh T, Akira S, Furuyama T, Lee C, Choi J, Rho J. TDAG51 promotes transcription factor FoxO1 activity during LPS-induced inflammatory responses. EMBO J 2023; 42:e111867. [PMID: 37203866 PMCID: PMC10308371 DOI: 10.15252/embj.2022111867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 04/28/2023] [Accepted: 05/03/2023] [Indexed: 05/20/2023] Open
Abstract
Tight regulation of Toll-like receptor (TLR)-mediated inflammatory responses is important for innate immunity. Here, we show that T-cell death-associated gene 51 (TDAG51/PHLDA1) is a novel regulator of the transcription factor FoxO1, regulating inflammatory mediator production in the lipopolysaccharide (LPS)-induced inflammatory response. TDAG51 induction by LPS stimulation was mediated by the TLR2/4 signaling pathway in bone marrow-derived macrophages (BMMs). LPS-induced inflammatory mediator production was significantly decreased in TDAG51-deficient BMMs. In TDAG51-deficient mice, LPS- or pathogenic Escherichia coli infection-induced lethal shock was reduced by decreasing serum proinflammatory cytokine levels. The recruitment of 14-3-3ζ to FoxO1 was competitively inhibited by the TDAG51-FoxO1 interaction, leading to blockade of FoxO1 cytoplasmic translocation and thereby strengthening FoxO1 nuclear accumulation. TDAG51/FoxO1 double-deficient BMMs showed significantly reduced inflammatory mediator production compared with TDAG51- or FoxO1-deficient BMMs. TDAG51/FoxO1 double deficiency protected mice against LPS- or pathogenic E. coli infection-induced lethal shock by weakening the systemic inflammatory response. Thus, these results indicate that TDAG51 acts as a regulator of the transcription factor FoxO1, leading to strengthened FoxO1 activity in the LPS-induced inflammatory response.
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Affiliation(s)
- Eui‐Soon Park
- Department of Microbiology and Molecular BiologyChungnam National UniversityDaejeonKorea
| | - Hyoeun Jeon
- Department of Microbiology and Molecular BiologyChungnam National UniversityDaejeonKorea
| | - Nari Lee
- Department of Microbiology and Molecular BiologyChungnam National UniversityDaejeonKorea
| | - Jiyeon Yu
- Department of Microbiology and Molecular BiologyChungnam National UniversityDaejeonKorea
| | - Hye‐Won Park
- Department of Microbiology and Molecular BiologyChungnam National UniversityDaejeonKorea
| | - Takashi Satoh
- Department of Immune Regulation, Graduate School of Medical and Dental SciencesTokyo Medical and Dental UniversityTokyoJapan
| | - Shizuo Akira
- Laboratory of Host Defense, WPI Immunology Frontier Research CenterOsaka UniversityOsakaJapan
| | - Tatsuo Furuyama
- Department of Clinical ExaminationKagawa Prefectural University of Health SciencesKagawaJapan
| | - Chul‐Ho Lee
- Laboratory Animal CenterKorea Research Institute of Bioscience & Biotechnology (KRIBB)DaejeonKorea
| | - Jong‐Soon Choi
- Division of Life ScienceKorea Basic Science Institute (KBSI)DaejeonKorea
| | - Jaerang Rho
- Department of Microbiology and Molecular BiologyChungnam National UniversityDaejeonKorea
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Teixeira-Nunes M, Retailleau P, Comisso M, Deruelle V, Mechold U, Renault L. Bacterial Nucleotidyl Cyclases Activated by Calmodulin or Actin in Host Cells: Enzyme Specificities and Cytotoxicity Mechanisms Identified to Date. Int J Mol Sci 2022; 23:ijms23126743. [PMID: 35743184 PMCID: PMC9223806 DOI: 10.3390/ijms23126743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 06/10/2022] [Accepted: 06/13/2022] [Indexed: 02/06/2023] Open
Abstract
Many pathogens manipulate host cell cAMP signaling pathways to promote their survival and proliferation. Bacterial Exoenzyme Y (ExoY) toxins belong to a family of invasive, structurally-related bacterial nucleotidyl cyclases (NC). Inactive in bacteria, they use proteins that are uniquely and abundantly present in eukaryotic cells to become potent, unregulated NC enzymes in host cells. Other well-known members of the family include Bacillus anthracis Edema Factor (EF) and Bordetella pertussis CyaA. Once bound to their eukaryotic protein cofactor, they can catalyze supra-physiological levels of various cyclic nucleotide monophosphates in infected cells. Originally identified in Pseudomonas aeruginosa, ExoY-related NC toxins appear now to be more widely distributed among various γ- and β-proteobacteria. ExoY-like toxins represent atypical, poorly characterized members within the NC toxin family. While the NC catalytic domains of EF and CyaA toxins use both calmodulin as cofactor, their counterparts in ExoY-like members from pathogens of the genus Pseudomonas or Vibrio use actin as a potent cofactor, in either its monomeric or polymerized form. This is an original subversion of actin for cytoskeleton-targeting toxins. Here, we review recent advances on the different members of the NC toxin family to highlight their common and distinct functional characteristics at the molecular, cytotoxic and enzymatic levels, and important aspects that need further characterizations.
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Affiliation(s)
- Magda Teixeira-Nunes
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France; (M.T.-N.); (M.C.)
| | - Pascal Retailleau
- Institut de Chimie des Substances Naturelles (ICSN), CNRS-UPR2301, Université Paris-Saclay, 1 Avenue de la Terrasse, 91198 Gif-sur-Yvette, France;
| | - Martine Comisso
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France; (M.T.-N.); (M.C.)
| | - Vincent Deruelle
- Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, CNRS UMR 3528, Institut Pasteur, 75015 Paris, France; (V.D.); (U.M.)
| | - Undine Mechold
- Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, CNRS UMR 3528, Institut Pasteur, 75015 Paris, France; (V.D.); (U.M.)
| | - Louis Renault
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France; (M.T.-N.); (M.C.)
- Correspondence:
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Silistre H, Raoux-Barbot D, Mancinelli F, Sangouard F, Dupin A, Belyy A, Deruelle V, Renault L, Ladant D, Touqui L, Mechold U. Prevalence of ExoY Activity in Pseudomonas aeruginosa Reference Panel Strains and Impact on Cytotoxicity in Epithelial Cells. Front Microbiol 2021; 12:666097. [PMID: 34675890 PMCID: PMC8524455 DOI: 10.3389/fmicb.2021.666097] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 07/30/2021] [Indexed: 11/13/2022] Open
Abstract
ExoY is among the effectors that are injected by the type III secretion system (T3SS) of Pseudomonas aeruginosa into host cells. Inside eukaryotic cells, ExoY interacts with F-actin, which stimulates its potent nucleotidyl cyclase activity to produce cyclic nucleotide monophosphates (cNMPs). ExoY has broad substrate specificity with GTP as a preferential substrate in vitro. How ExoY contributes to the virulence of P. aeruginosa remains largely unknown. Here, we examined the prevalence of active ExoY among strains from the international P. aeruginosa reference panel, a collection of strains that includes environmental and clinical isolates, commonly used laboratory strains, and sequential clonal isolates from cystic fibrosis (CF) patients and thus represents the large diversity of this bacterial species. The ability to secrete active ExoY was determined by measuring the F-actin stimulated guanylate cyclase (GC) activity in bacterial culture supernatants. We found an overall ExoY activity prevalence of about 60% among the 40 examined strains with no significant difference between CF and non-CF isolates. In parallel, we used cellular infection models of human lung epithelial cells to compare the cytotoxic effects of isogenic reference strains expressing active ExoY or lacking the exoY gene. We found that P. aeruginosa strains lacking ExoY were in fact more cytotoxic to the epithelial cells than those secreting active ExoY. This suggests that under certain conditions, ExoY might partly alleviate the cytotoxic effects of other virulence factors of P. aeruginosa.
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Affiliation(s)
- Hazel Silistre
- Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, Paris, France
| | - Dorothée Raoux-Barbot
- Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, Paris, France
| | - Federica Mancinelli
- Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, Paris, France
| | - Flora Sangouard
- Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, Paris, France
| | - Alice Dupin
- Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, Paris, France
| | - Alexander Belyy
- Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, Paris, France
| | - Vincent Deruelle
- Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, Paris, France
| | - Louis Renault
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Daniel Ladant
- Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, Paris, France
| | - Lhousseine Touqui
- Mucoviscidose: Physiopathologie et Phénogénomique, Centre de Recherche Saint-Antoine (CRSA), INSERM UMR S 938, Sorbonne Université, Paris, France.,Mucoviscidose et Bronchopathies Chroniques, Département Santé Globale, Institute Pasteur, Paris, France
| | - Undine Mechold
- Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, Paris, France
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Pseudomonas aeruginosa ExsA Regulates a Metalloprotease, ImpA, That Inhibits Phagocytosis of Macrophages. Infect Immun 2019; 87:IAI.00695-19. [PMID: 31527124 DOI: 10.1128/iai.00695-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 09/09/2019] [Indexed: 02/08/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogenic bacterium whose type III secretion system (T3SS) plays a critical role in acute infections. Translocation of the T3SS effectors into host cells induces cytotoxicity. In addition, the T3SS promotes the intracellular growth of P. aeruginosa during host infections. The T3SS regulon genes are regulated by an AraC-type regulator, ExsA. In this study, we found that an extracellular metalloprotease encoded by impA (PA0572) is under the regulation of ExsA. An ExsA consensus binding sequence was identified upstream of the impA gene, and direct binding of the site by ExsA was demonstrated via an electrophoretic mobility shift assay. We further demonstrate that secreted ImpA cleaves the macrophage surface protein CD44, which inhibits the phagocytosis of the bacterial cells by macrophages. Combined, our results reveal a novel ExsA-regulated virulence factor that cooperatively inhibits the functions of macrophages with the T3SS.
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5
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Distinct susceptibilities of corneal Pseudomonas aeruginosa clinical isolates to neutrophil extracellular trap-mediated immunity. Infect Immun 2014; 82:4135-43. [PMID: 25047845 DOI: 10.1128/iai.02169-14] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Ocular bacterial keratitis, often associated with Pseudomonas aeruginosa bacterial infection, commonly occurs in contact lens wearers and may lead to vision impairment. In this study, we analyzed the contribution of neutrophil extracellular traps (NETs) to the mediation of protection during ocular keratitis. Both invasive and cytotoxic P. aeruginosa clinical isolates induced NET release by neutrophils. NETs carried the characteristic histone proteins, elastase, lysozyme, myeloperoxidase, and metabolic enzymes. While the invasive P. aeruginosa strains PAO1 (serogroup O5) and 6294 (serogroup O6) were trapped by NETs, the cytotoxic P. aeruginosa strains 6077, 6206 (serogroup O11), and PA14 (serogroup 010) were less sensitive to NET capture. The mechanism of escape by the cytotoxic strains from adhesion to NETs involved the shedding of outer membrane vesicles (OMVs) that outcompeted the cytotoxic P. aeruginosa strains for NET binding. When ocular infection was caused by an invasive strain in vivo, NETs were released at the ocular surface to capture bacteria, limiting their spread. Treatment with MNase I had a dose-dependent effect, with low doses of MNase speeding up bacterial clearance and high doses of MNase having toxic consequences. Cumulatively, our data suggest that NET-mediated immunity is a two-step process. Initially, pathogens attach to NET fragments; subsequently, upon nuclease activity, active serine proteases, which proteolytically degrade NET-associated proteins and promote DNase activity, are released. Therefore, a balance between NET production and NET degradation is needed to achieve maximal NET immunity.
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Smith SB, Magid-Slav M, Brown JR. Host response to respiratory bacterial pathogens as identified by integrated analysis of human gene expression data. PLoS One 2013; 8:e75607. [PMID: 24086587 PMCID: PMC3785471 DOI: 10.1371/journal.pone.0075607] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 08/20/2013] [Indexed: 01/24/2023] Open
Abstract
Respiratory bacterial pathogens are one of the leading causes of infectious death in the world and a major health concern complicated by the rise of multi-antibiotic resistant strains. Therapeutics that modulate host genes essential for pathogen infectivity could potentially avoid multi-drug resistance and provide a wider scope of treatment options. Here, we perform an integrative analysis of published human gene expression data generated under challenges from the gram-negative and Gram-positive bacteria pathogens, Pseudomonas aeruginosa and Streptococcus pneumoniae, respectively. We applied a previously described differential gene and pathway enrichment analysis pipeline to publicly available host mRNA GEO datasets resulting from exposure to bacterial infection. We found 72 canonical human pathways common between four GEO datasets, representing P. aeruginosa and S. pneumoniae. Although the majority of these pathways are known to be involved with immune response, we found several interesting new interactions such as the SUMO1 pathway that might have a role in bacterial infections. Furthermore, 36 host-bacterial pathways were also shared with our previous results for respiratory virus host gene expression. Based on our pathway analysis we propose several drug-repurposing opportunities supported by the literature.
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Affiliation(s)
- Steven B. Smith
- Computational Biology, Quantitative Sciences, GlaxoSmithKline, Collegeville, Pennsylvania, United States of America
- Institute for Genome Science, University of Maryland, Baltimore, Maryland, United States of America
| | - Michal Magid-Slav
- Computational Biology, Quantitative Sciences, GlaxoSmithKline, Collegeville, Pennsylvania, United States of America
| | - James R. Brown
- Computational Biology, Quantitative Sciences, GlaxoSmithKline, Collegeville, Pennsylvania, United States of America
- * E-mail:
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7
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Galle M, Carpentier I, Beyaert R. Structure and function of the Type III secretion system of Pseudomonas aeruginosa. Curr Protein Pept Sci 2012; 13:831-42. [PMID: 23305368 PMCID: PMC3706959 DOI: 10.2174/138920312804871210] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 07/19/2012] [Accepted: 07/25/2012] [Indexed: 02/08/2023]
Abstract
Pseudomonas aeruginosa is a dangerous pathogen particularly because it harbors multiple virulence factors. It causes several types of infection, including dermatitis, endocarditis, and infections of the urinary tract, eye, ear, bone, joints and, of particular interest, the respiratory tract. Patients with cystic fibrosis, who are extremely susceptible to Pseudomonas infections, have a bad prognosis and high mortality. An important virulence factor of P. aeruginosa, shared with many other gram-negative bacteria, is the type III secretion system, a hollow molecular needle that transfers effector toxins directly from the bacterium into the host cell cytosol. This complex macromolecular machine works in a highly regulated manner and can manipulate the host cell in many different ways. Here we review the current knowledge of the structure of the P. aeruginosa T3SS, as well as its function and recognition by the immune system. Furthermore, we describe recent progress in the development and use of therapeutic agents targeting the T3SS.
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Affiliation(s)
- Marlies Galle
- Department of Biomedical Molecular Biology, Ghent University, Technologiepark 927, B-9052 Ghent, Belgium; the
- Department for Molecular Biomedical Research, Unit of Molecular Signal Transduction in Inflammation, VIB, Technologiepark 927, B-9052 Ghent, Belgium
| | - Isabelle Carpentier
- Department of Biomedical Molecular Biology, Ghent University, Technologiepark 927, B-9052 Ghent, Belgium; the
- Department for Molecular Biomedical Research, Unit of Molecular Signal Transduction in Inflammation, VIB, Technologiepark 927, B-9052 Ghent, Belgium
| | - Rudi Beyaert
- Department of Biomedical Molecular Biology, Ghent University, Technologiepark 927, B-9052 Ghent, Belgium; the
- Department for Molecular Biomedical Research, Unit of Molecular Signal Transduction in Inflammation, VIB, Technologiepark 927, B-9052 Ghent, Belgium
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8
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In vivo discrimination of type 3 secretion system-positive and -negative Pseudomonas aeruginosa via a caspase-1-dependent pathway. Infect Immun 2010; 78:4744-53. [PMID: 20823203 DOI: 10.1128/iai.00744-10] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Microbe-associated molecular patterns are recognized by Toll-like receptors of the innate immune system. This recognition enables a rapid response to potential pathogens but does not clearly provide a way for the innate immune system to discriminate between virulent and avirulent microbes. We find that pulmonary infection of mice with type 3 translocation-competent Pseudomonas aeruginosa triggers a rapid inflammatory response, while infection with isogenic translocation-deficient mutants does not. Discrimination between translocon-positive and -negative bacteria requires caspase-1 activity in bone marrow-derived cells and interleukin-1 receptor signaling. Thus, the activation of caspase-1 by bacteria expressing type 3 secretion systems allows for rapid recognition of bacteria expressing conserved functions associated with virulence.
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9
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Yang SK, Wang YC, Chao CC, Chuang YJ, Lan CY, Chen BS. Dynamic cross-talk analysis among TNF-R, TLR-4 and IL-1R signalings in TNFalpha-induced inflammatory responses. BMC Med Genomics 2010; 3:19. [PMID: 20497537 PMCID: PMC2889840 DOI: 10.1186/1755-8794-3-19] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 05/24/2010] [Indexed: 12/16/2022] Open
Abstract
Background Development in systems biology research has accelerated in recent years, and the reconstructions for molecular networks can provide a global view to enable in-depth investigation on numerous system properties in biology. However, we still lack a systematic approach to reconstruct the dynamic protein-protein association networks at different time stages from high-throughput data to further analyze the possible cross-talks among different signaling/regulatory pathways. Methods In this study we integrated protein-protein interactions from different databases to construct the rough protein-protein association networks (PPANs) during TNFα-induced inflammation. Next, the gene expression profiles of TNFα-induced HUVEC and a stochastic dynamic model were used to rebuild the significant PPANs at different time stages, reflecting the development and progression of endothelium inflammatory responses. A new cross-talk ranking method was used to evaluate the potential core elements in the related signaling pathways of toll-like receptor 4 (TLR-4) as well as receptors for tumor necrosis factor (TNF-R) and interleukin-1 (IL-1R). Results The highly ranked cross-talks which are functionally relevant to the TNFα pathway were identified. A bow-tie structure was extracted from these cross-talk pathways, suggesting the robustness of network structure, the coordination of signal transduction and feedback control for efficient inflammatory responses to different stimuli. Further, several characteristics of signal transduction and feedback control were analyzed. Conclusions A systematic approach based on a stochastic dynamic model is proposed to generate insight into the underlying defense mechanisms of inflammation via the construction of corresponding signaling networks upon specific stimuli. In addition, this systematic approach can be applied to other signaling networks under different conditions in different species. The algorithm and method proposed in this study could expedite prospective systems biology research when better experimental techniques for protein expression detection and microarray data with multiple sampling points become available in the future.
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Affiliation(s)
- Shih-Kuang Yang
- Laboratory of Control and Systems Biology, Department of Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan
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10
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Heiniger RW, Winther-Larsen HC, Pickles RJ, Koomey M, Wolfgang MC. Infection of human mucosal tissue by Pseudomonas aeruginosa requires sequential and mutually dependent virulence factors and a novel pilus-associated adhesin. Cell Microbiol 2010; 12:1158-73. [PMID: 20331639 DOI: 10.1111/j.1462-5822.2010.01461.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tissue damage predisposes humans to life-threatening disseminating infection by the opportunistic pathogen Pseudomonas aeruginosa. Bacterial adherence to host tissue is a critical first step in this infection process. It is well established that P. aeruginosa attachment to host cells involves type IV pili (TFP), which are retractile surface fibres. The molecular details of attachment and the identity of the bacterial adhesin and host receptor remain controversial. Using a mucosal epithelium model system derived from primary human tissue, we show that the pilus-associated protein PilY1 is required for bacterial adherence. We establish that P. aeruginosa preferentially binds to exposed basolateral host cell surfaces, providing a mechanistic explanation for opportunistic infection of damaged tissue. Further, we demonstrate that invasion and fulminant infection of intact host tissue requires the coordinated and mutually dependent action of multiple bacterial factors, including pilus fibre retraction and the host cell intoxication system, termed type III secretion. Our findings offer new and important insights into the complex interactions between a pathogen and its human host and provide compelling evidence that PilY1 serves as the principal P. aeruginosa adhesin for human tissue and that it specifically recognizes a host receptor localized or enriched on basolateral epithelial cell surfaces.
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Affiliation(s)
- Ryan W Heiniger
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
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11
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Abstract
The Gram-negative bacterium Pseudomonas aeruginosa uses a complex type III secretion apparatus to inject effector proteins into host cells. The configuration of this secretion machinery, the activities of the proteins that are injected by it and the consequences of this process for infection are now being elucidated. This Review summarizes our current knowledge of P. aeruginosa type III secretion, including the secretion and translocation machinery, the regulation of this machinery, and the associated chaperones and effector proteins. The features of this interesting secretion system have important implications for the pathogenesis of P. aeruginosa infections and for other type III secretion systems.
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Affiliation(s)
- Alan R Hauser
- Departments of MicrobiologyImmunology and Medicine, Northwestern University, Chicago, Illinois 60611, USA.
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12
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Brannon MK, Davis JM, Mathias JR, Hall CJ, Emerson JC, Crosier PS, Huttenlocher A, Ramakrishnan L, Moskowitz SM. Pseudomonas aeruginosa Type III secretion system interacts with phagocytes to modulate systemic infection of zebrafish embryos. Cell Microbiol 2009; 11:755-68. [PMID: 19207728 DOI: 10.1111/j.1462-5822.2009.01288.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen that can cause serious infection in those with deficient or impaired phagocytes. We have developed the optically transparent and genetically tractable zebrafish embryo as a model for systemic P. aeruginosa infection. Despite lacking adaptive immunity at this developmental stage, zebrafish embryos were highly resistant to P. aeruginosa infection, but as in humans, phagocyte depletion dramatically increased their susceptibility. The virulence of an attenuated P. aeruginosa strain lacking a functional Type III secretion system was restored upon phagocyte depletion, suggesting that this system influences virulence through its effects on phagocytes. Intravital imaging revealed bacterial interactions with multiple blood cell types. Neutrophils and macrophages rapidly phagocytosed and killed P. aeruginosa, suggesting that both cell types play a role in protection against infection. Intravascular aggregation of erythrocytes and other blood cells with resultant circulatory blockage was observed immediately upon infection, which may be relevant to the pathogenesis of thrombotic complications of human P. aeruginosa infections. The real-time visualization capabilities and genetic tractability of the zebrafish infection model should enable elucidation of molecular and cellular details of P. aeruginosa pathogenesis in conditions associated with neutropenia or impaired phagocyte function.
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Affiliation(s)
- Mark K Brannon
- Department of Pediatrics, University of Washington, Seattle, WA, USA
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13
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Munford RS. Sensing gram-negative bacterial lipopolysaccharides: a human disease determinant? Infect Immun 2008; 76:454-65. [PMID: 18086818 PMCID: PMC2223455 DOI: 10.1128/iai.00939-07] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Robert S Munford
- Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas 75390-9113, USA.
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14
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Franchi L, Stoolman J, Kanneganti TD, Verma A, Ramphal R, Núñez G. Critical role for Ipaf inPseudomonas aeruginosa-induced caspase-1 activation. Eur J Immunol 2007; 37:3030-9. [DOI: 10.1002/eji.200737532] [Citation(s) in RCA: 217] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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15
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Burrack LS, Higgins DE. Genomic approaches to understanding bacterial virulence. Curr Opin Microbiol 2006; 10:4-9. [PMID: 17161645 DOI: 10.1016/j.mib.2006.11.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Accepted: 11/30/2006] [Indexed: 01/12/2023]
Abstract
The genomic sequences of bacterial pathogens and of the host species they infect have greatly increased the understanding of host-pathogen interactions. Sequences of bacterial genomes have led to the identification of virulence factors through the use of bioinformatics, targeted mutant library construction, screening approaches combining transposon mutagenesis and microarray technology, and through the expression of libraries of bacterial proteins within model organisms such as yeast. Host genomic information has also yielded insights into bacterial virulence through transcriptional profiling of host responses to infection and identification of host proteins required for bacterial pathogenicity using knockdown of host gene product expression during infection. Research using genomic approaches to bacterial pathogenesis is a rapidly growing field and will expand further as additional bacterial genome sequences become available and techniques for conducting high-throughput analysis are refined.
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Affiliation(s)
- Laura S Burrack
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA 02115, USA
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16
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O'Grady EP, Mulcahy H, O'Callaghan J, Adams C, O'Gara F. Pseudomonas aeruginosa infection of airway epithelial cells modulates expression of Kruppel-like factors 2 and 6 via RsmA-mediated regulation of type III exoenzymes S and Y. Infect Immun 2006; 74:5893-902. [PMID: 16988269 PMCID: PMC1594899 DOI: 10.1128/iai.00489-06] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Pseudomonas aeruginosa is an important opportunistic pathogen which is capable of causing both acute and chronic infections in immunocompromised patients. Successful adaptation of the bacterium to its host environment relies on the ability of the organism to tightly regulate gene expression. RsmA, a small RNA-binding protein, controls the expression of a large number of virulence-related genes in P. aeruginosa, including those encoding the type III secretion system and associated effector proteins, with important consequences for epithelial cell morphology and cytotoxicity. In order to examine the influence of RsmA-regulated functions in the pathogen on gene expression in the host, we compared global expression profiles of airway epithelial cells in response to infection with P. aeruginosa PAO1 and an rsmA mutant. The RsmA-dependent response of host cells was characterized by significant changes in the global transcriptional pattern, including the increased expression of two Kruppel-like factors, KLF2 and KLF6. This increased expression was mediated by specific type III effector proteins. ExoS was required for the enhanced expression of KLF2, whereas both ExoS and ExoY were required for the enhanced expression of KLF6. Neither ExoT nor ExoU influenced the expression of the transcription factors. Additionally, the increased gene expression of KLF2 and KLF6 was associated with ExoS-mediated cytotoxicity. Therefore, this study identifies for the first time the human transcription factors KLF2 and KLF6 as targets of the P. aeruginosa type III exoenzymes S and Y, with potential importance in host cell death.
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Affiliation(s)
- Eoin P O'Grady
- BIOMERIT Research Centre, Department of Microbiology, University College Cork, Cork, Ireland
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Shaver CM, Hauser AR. Interactions between effector proteins of the Pseudomonas aeruginosa type III secretion system do not significantly affect several measures of disease severity in mammals. MICROBIOLOGY-SGM 2006; 152:143-152. [PMID: 16385124 DOI: 10.1099/mic.0.28368-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The effector proteins of the type III secretion systems of many bacterial pathogens act in a coordinated manner to subvert host cells and facilitate the development and progression of disease. It is unclear whether interactions between the type-III-secreted proteins of Pseudomonas aeruginosa result in similar effects on the disease process. We have previously characterized the contributions to pathogenesis of the type-III-secreted proteins ExoS, ExoT and ExoU when secreted individually. In this study, we extend our prior work to determine whether these proteins have greater than expected effects on virulence when secreted in combination. In vitro cytotoxicity and anti-internalization activities were not enhanced when effector proteins were secreted in combinations rather than alone. Likewise in a mouse model of pneumonia, bacterial burden in the lungs, dissemination and mortality attributable to ExoS, ExoT and ExoU were not synergistically increased when combinations of these effector proteins were secreted. Because of the absence of an appreciable synergistic increase in virulence when multiple effector proteins were secreted in combination, we conclude that any cooperation between ExoS, ExoT and ExoU does not translate into a synergistically significant enhancement of disease severity as measured by these assays.
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Affiliation(s)
- Ciara M Shaver
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, 303 East Chicago Avenue, Searle 6-495, Chicago, IL 60611, USA
| | - Alan R Hauser
- Department of Medicine, Northwestern University Feinberg School of Medicine, 303 East Chicago Avenue, Searle 6-495, Chicago, IL 60611, USA
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, 303 East Chicago Avenue, Searle 6-495, Chicago, IL 60611, USA
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