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Nagao I, Kawasaki M, Goyama T, Kim HJ, Call DR, Ambrosini YM. Enterohemorrhagic Escherichia coli (EHEC) disrupts intestinal barrier integrity in translational canine stem cell-derived monolayers. Microbiol Spectr 2024; 12:e0096124. [PMID: 39162490 PMCID: PMC11448187 DOI: 10.1128/spectrum.00961-24] [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: 05/14/2024] [Accepted: 06/30/2024] [Indexed: 08/21/2024] Open
Abstract
This study addresses the gap in translatable in vitro models for investigating Enterohemorrhagic E. coli (EHEC) infections, particularly relevant to both canine and human health. EHEC is known to induce acute colitis in dogs, leading to symptoms like hemorrhagic diarrhea and hemolytic uremic syndrome, similar to those observed in humans. However, understanding the pathophysiology and developing treatment strategies have been challenging due to the lack of effective models that replicate the clinical disease caused by EHEC in both species. Our approach involved the development of colonoid-derived monolayers using intestinal tissues from healthy, client-owned dogs. These monolayers were exposed to EHEC, and the impact of EHEC was assessed through several techniques, including trans-epithelial electrical resistance (TEER) measurement, immunofluorescence staining for junction proteins and mucus, and scanning electron microscopy for morphological analysis. Modified culture with saline, which was intended to prevent bacterial overgrowth, maintained barrier integrity and cell differentiation. EHEC infection led to significant decreases in TEER and ZO-1 expression, but not in E-cadherin levels or mucus production. In addition, EHEC elicited a notable increase in tumor necrosis factor-alpha production, highlighting its distinct impact on canine intestinal epithelial cells compared to non-pathogenic E. coli. These findings closely replicate in vivo observations in dogs and humans with EHEC enteropathy, validating the canine colonoid-derived monolayer system as a translational model to study host-pathogen interactions in EHEC and potentially other clinically significant enteric pathogens. IMPORTANCE This study develops a new model to better understand Enterohemorrhagic E. coli (EHEC) infections, a serious bacterial disease affecting both dogs and humans, characterized by symptoms such as hemorrhagic diarrhea and hemolytic uremic syndrome. Traditional research models have fallen short of mimicking how this disease manifests in patients. Our research used intestinal tissues from healthy dogs to create layers of cells, known as colonoid-derived monolayers, which we then exposed to EHEC. We assessed the damage caused by the bacteria using several techniques, observing significant changes similar to those seen in actual cases of the disease. The model proved effective in replicating the interaction between the host and the pathogen, marking an important step toward understanding EHEC's effects and developing treatments. This canine colonoid-derived monolayer system not only bridges a crucial gap in current research but also offers a promising platform for studying other enteric pathogens affecting both canine and human health.
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Affiliation(s)
- Itsuma Nagao
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
- Department of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Minae Kawasaki
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - Takashi Goyama
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - Hyun Jung Kim
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Douglas R. Call
- Paul G. Allen School for Global Health, Washington State University, Pullman, Washington, USA
| | - Yoko M. Ambrosini
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
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2
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Miner MV, Rauch I. Why put yourself on a pedestal? The pathogenic role of the A/E pedestal. Infect Immun 2024; 92:e0048923. [PMID: 38591884 PMCID: PMC11384751 DOI: 10.1128/iai.00489-23] [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] [Indexed: 04/10/2024] Open
Abstract
Certain Escherichia coli (E. coli) strains are attaching and effacing (A/E) lesion pathogens that primarily infect intestinal epithelial cells. They cause actin restructuring and polymerization within the host cell to create an actin-rich protrusion below the site of adherence, termed the pedestal. Although there is clarity on the pathways initiating pedestal formation, the underlying purpose(s) of the pedestal remains ambiguous. The conservation of pedestal-forming activity across multiple pathogens and redundancy in formation pathways indicate a pathogenic advantage. However, few decisive conclusions have been drawn, given that the results vary between model systems. Some research argues that the pedestal increases the colonization capability of the bacterium. These studies utilize A/E pathogens specifically deficient in pedestal formation to evaluate adhesion and intestinal colonization following infection. There have been many proposed mechanisms for the colonization benefit conferred by the pedestal. One suggested benefit is that the pedestal allows for direct cytosolic anchoring through incorporation of the established host cortical actin, causing a stable link between the pathogen and cell structure. The pedestal may confer enhanced motility, as enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC) are better able to migrate on the surface of host cells and infect neighboring cells in the presence of the pedestal. Additionally, some research suggests that the pedestal improves effector delivery. This review will investigate the purpose of pedestal formation using evidence from recent literature and will critically evaluate the methodology and model systems. Most importantly, we will contextualize the proposed functions to reconcile potential synergistic effects.
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Affiliation(s)
- M. V. Miner
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
| | - I. Rauch
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
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3
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Srivastava R, González-Prieto C, Lynch JP, Muscolo ME, Lin CY, Brown MA, Lemos L, Shrestha A, Osburne MS, Leong JM, Lesser CF. In situ deposition of nanobodies by an engineered commensal microbe promotes survival in a mouse model of enterohemorrhagic E. coli. PNAS NEXUS 2024; 3:pgae374. [PMID: 39262854 PMCID: PMC11388102 DOI: 10.1093/pnasnexus/pgae374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2024] [Accepted: 08/15/2024] [Indexed: 09/13/2024]
Abstract
Engineered smart microbes that deliver therapeutic payloads are emerging as treatment modalities, particularly for diseases with links to the gastrointestinal tract. Enterohemorrhagic Escherichia coli (EHEC) is a causative agent of potentially lethal hemolytic uremic syndrome. Given concerns that antibiotic treatment increases EHEC production of Shiga toxin (Stx), which is responsible for systemic disease, novel remedies are needed. EHEC encodes a type III secretion system (T3SS) that injects Tir into enterocytes. Tir inserts into the host cell membrane, exposing an extracellular domain that subsequently binds intimin, one of its outer membrane proteins, triggering the formation of attaching and effacing (A/E) lesions that promote EHEC mucosal colonization. Citrobacter rodentium (Cr), a natural A/E mouse pathogen, similarly requires Tir and intimin for its pathogenesis. Mice infected with Cr(ΦStx2dact), a variant lysogenized with an EHEC-derived phage that produces Stx2dact, develop intestinal A/E lesions and toxin-dependent disease. Stx2a is more closely associated with human disease. By developing an efficient approach to seamlessly modify the C. rodentium genome, we generated Cr_Tir-MEHEC(ΦStx2a), a variant that expresses Stx2a and the EHEC extracellular Tir domain. We found that mouse precolonization with HS-PROT3EcT-TD4, a human commensal E. coli strain (E. coli HS) engineered to efficiently secrete an anti-EHEC Tir nanobody, delayed bacterial colonization and improved survival after challenge with Cr_Tir-MEHEC(ΦStx2a). This study suggests that commensal E. coli engineered to deliver payloads that block essential virulence determinants can be developed as a new means to prevent and potentially treat infections including those due to antibiotic resistant microbes.
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Affiliation(s)
- Rajkamal Srivastava
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, MA 02115, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Coral González-Prieto
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, MA 02115, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Jason P Lynch
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, MA 02115, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Michele E Muscolo
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, MA 02115, USA
| | - Catherine Y Lin
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, MA 02115, USA
| | - Markus A Brown
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, MA 02115, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Luisa Lemos
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, MA 02115, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Anishma Shrestha
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Marcia S Osburne
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - John M Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA
- Tufts Stuart B Levy Center for Integrated Management of Antimicrobial Resistance, Tufts University, Boston, MA 02111, USA
| | - Cammie F Lesser
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, MA 02115, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Ragon Institute of Harvard and MIT, Cambridge, MA 02139, USA
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4
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Martins FH, Rosay T, Rajan A, Carter HE, Turocy T, Mejia A, Crawford JM, Maresso AW, Sperandio V. Enterococcus faecalis-derived adenine enhances enterohaemorrhagic Escherichia coli Type 3 Secretion System-dependent virulence. Nat Microbiol 2024; 9:2448-2461. [PMID: 38965331 DOI: 10.1038/s41564-024-01747-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 05/30/2024] [Indexed: 07/06/2024]
Abstract
Interactions between microbiota and enteric pathogens can promote colonization resistance or enhance pathogenesis. The pathobiont Enterococcus faecalis increases enterohaemorrhagic E. coli (EHEC) virulence by upregulating Type 3 Secretion System (T3SS) expression, effector translocation, and attaching and effacing (AE) lesion formation on enterocytes, but the mechanisms underlying this remain unknown. Using co-infection of organoids, metabolomics, supplementation experiments and bacterial genetics, here we show that co-culture of EHEC with E. faecalis increases the xanthine-hypoxanthine pathway activity and adenine biosynthesis. Adenine or E. faecalis promoted T3SS gene expression, while transcriptomics showed upregulation of adeP expression, which encodes an adenine importer. Mechanistically, adenine relieved High hemolysin activity (Hha)-dependent repression of T3SS gene expression in EHEC and promoted AE lesion formation in an AdeP-dependent manner. Microbiota-derived purines, such as adenine, support multiple beneficial host responses; however, our data show that this metabolite also increases EHEC virulence, highlighting the complexity of pathogen-microbiota-host interactions in the gut.
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Affiliation(s)
- Fernando H Martins
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Thibaut Rosay
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Anubama Rajan
- TAILOR Labs, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Hannah E Carter
- TAILOR Labs, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Tayah Turocy
- Department of Chemistry, Yale University, New Haven, CT, USA
- Institute of Biomolecular Design and Discovery, Yale University, West Haven, CT, USA
| | - Andres Mejia
- Research Animal Resources and Compliance, University of Wisconsin-Madison, Madison, WI, USA
| | - Jason M Crawford
- Department of Chemistry, Yale University, New Haven, CT, USA
- Institute of Biomolecular Design and Discovery, Yale University, West Haven, CT, USA
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Anthony W Maresso
- TAILOR Labs, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Vanessa Sperandio
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA.
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5
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Srivastava R, González-Prieto C, Lynch JP, Muscolo M, Lin CY, Brown MA, Lemos L, Shrestha A, Osburne MS, Leong JM, Lesser CF. In situ deposition of nanobodies by an engineered commensal microbe promotes survival in a mouse model of enterohemorrhagic E. coli. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.30.605899. [PMID: 39131305 PMCID: PMC11312530 DOI: 10.1101/2024.07.30.605899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
Engineered smart microbes that deliver therapeutic payloads are emerging as treatment modalities, particularly for diseases with links to the gastrointestinal tract. Enterohemorrhagic E coli (EHEC) is a causative agent of potentially lethal hemolytic uremic syndrome. Given concerns that antibiotic treatment increases EHEC production of Shiga toxin (Stx), which is responsible for systemic disease, novel remedies are needed. EHEC encodes a type III secretion system (T3SS) that injects Tir into enterocytes. Tir inserts into the host cell membrane, exposing an extracellular domain that subsequently binds intimin, one of its outer membrane proteins, triggering the formation of attaching and effacing (A/E) lesions that promote EHEC mucosal colonization. Citrobacter rodentium (Cr), a natural A/E mouse pathogen, similarly requires Tir and intimin for its pathogenesis. Mice infected with Cr(ΦStx2dact), a variant lysogenized with an EHEC-derived phage that produces Stx2dact, develop intestinal A/E lesions and toxin-dependent disease. Stx2a is more closely associated with human disease. By developing an efficient approach to seamlessly modify the C. rodentium genome, we generated Cr_Tir-MEHEC(ΦStx2a), a variant that expresses Stx2a and the EHEC extracellular Tir domain. We found that mouse pre-colonization with HS-PROT3EcT-TD4, a human commensal E. coli strain (E. coli HS) engineered to efficiently secrete- an anti-EHEC Tir nanobody, delayed bacterial colonization and improved survival after challenge with Cr_Tir-MEHEC(ΦStx2a). This study provides the first evidence to support the efficacy of engineered commensal E. coli to intestinally deliver therapeutic payloads that block essential enteric pathogen virulence determinants, a strategy that may serve as an antibiotic-independent antibacterial therapeutic modality.
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Affiliation(s)
- Rajkamal Srivastava
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, MA, 02115, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Coral González-Prieto
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, MA, 02115, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Jason P Lynch
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, MA, 02115, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Michele Muscolo
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, MA, 02115, USA
| | - Catherine Y Lin
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, MA, 02115, USA
| | - Markus A Brown
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, MA, 02115, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Luisa Lemos
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, MA, 02115, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Anishma Shrestha
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, 02111, USA
| | - Marcia S Osburne
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, 02111, USA
| | - John M Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, 02111, USA
- Tufts Stuart B Levy Center for Integrated Management of Antimicrobial Resistance, Tufts University, Boston, MA, 02111, USA
| | - Cammie F Lesser
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, MA, 02115, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- Ragon Institute of Harvard and MIT, Cambridge, MA, 02139, USA
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6
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Bowser S, Melton-Celsa A, Chapartegui-González I, Torres AG. Further Evaluation of Enterohemorrhagic Escherichia coli Gold Nanoparticle Vaccines Utilizing Citrobacter rodentium as the Model Organism. Vaccines (Basel) 2024; 12:508. [PMID: 38793759 PMCID: PMC11125983 DOI: 10.3390/vaccines12050508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 04/26/2024] [Accepted: 05/03/2024] [Indexed: 05/26/2024] Open
Abstract
Enterohemorrhagic E. coli (EHEC) is a group of pathogenic bacteria that is associated with worldwide human foodborne diarrheal illnesses and the development of hemolytic uremic syndrome, a potentially deadly condition associated with Shiga toxins (Stxs). Currently, approved vaccines for human prophylaxis against infection do not exist, and one barrier preventing the successful creation of EHEC vaccines is the absence of dependable animal models, including mice, which are naturally resistant to EHEC infection and do not manifest the characteristic signs of the illness. Our lab previously developed gold nanoparticle (AuNP)-based EHEC vaccines, and assessed their efficacy using Citrobacter rodentium, which is the mouse pathogen counterpart of EHEC, along with an Stx2d-producing strain that leads to more consistent disease kinetics in mice, including lethality. The purpose of this study was to continue evaluating these vaccines to increase protection. Here, we demonstrated that subcutaneous immunization of mice with AuNPs linked to the EHEC antigens EscC and intimin (Eae), either alone or simultaneously, elicits functional robust systemic humoral responses. Additionally, vaccination with both antigens together showed some efficacy against Stx2d-producing C. rodentium while AuNP-EscC successfully limited infection with non-Stx2d-producing C. rodentium. Overall, the collected results indicate that our AuNP vaccines have promising potential for preventing disease with EHEC, and that evaluation of novel vaccines using an appropriate animal model, like C. rodentium described here, could be the key to finally developing an effective EHEC vaccine that can progress into human clinical trials.
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Affiliation(s)
- Sarah Bowser
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Angela Melton-Celsa
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | | | - Alfredo G. Torres
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX 77555, USA
- Department of Pathology, The University of Texas Medical Branch, Galveston, TX 77555, USA
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7
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Mühlen S, Heroven AK, Elxnat B, Kahl S, Pieper DH, Dersch P. Infection and antibiotic-associated changes in the fecal microbiota of C. rodentium ϕ stx2dact-infected C57BL/6 mice. Antimicrob Agents Chemother 2024; 68:e0005724. [PMID: 38526080 PMCID: PMC11064522 DOI: 10.1128/aac.00057-24] [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: 01/17/2024] [Accepted: 02/24/2024] [Indexed: 03/26/2024] Open
Abstract
Enterohemorrhagic Escherichia coli causes watery to bloody diarrhea, which may progress to hemorrhagic colitis and hemolytic-uremic syndrome. While early studies suggested that antibiotic treatment may worsen the pathology of an enterohemorrhagic Escherichia coli (EHEC) infection, recent work has shown that certain non-Shiga toxin-inducing antibiotics avert disease progression. Unfortunately, both intestinal bacterial infections and antibiotic treatment are associated with dysbiosis. This can alleviate colonization resistance, facilitate secondary infections, and potentially lead to more severe illness. To address the consequences in the context of an EHEC infection, we used the established mouse infection model organism Citrobacter rodentium ϕstx2dact and monitored changes in fecal microbiota composition during infection and antibiotic treatment. C. rodentium ϕstx2dact infection resulted in minor changes compared to antibiotic treatment. The infection caused clear alterations in the microbial community, leading mainly to a reduction of Muribaculaceae and a transient increase in Enterobacteriaceae distinct from Citrobacter. Antibiotic treatments of the infection resulted in marked and distinct variations in microbiota composition, diversity, and dispersion. Enrofloxacin and trimethoprim/sulfamethoxazole, which did not prevent Shiga toxin-mediated organ damage, had the least disruptive effects on the intestinal microbiota, while kanamycin and tetracycline, which rapidly cleared the infection without causing organ damage, caused a severe reduction in diversity. Kanamycin treatment resulted in the depletion of all but Bacteroidetes genera, whereas tetracycline effects on Clostridia were less severe. Together, these data highlight the need to address the impact of individual antibiotics in the clinical care of life-threatening infections and consider microbiota-regenerating therapies.IMPORTANCEUnderstanding the impact of antibiotic treatment on EHEC infections is crucial for appropriate clinical care. While discouraged by early studies, recent findings suggest certain antibiotics can impede disease progression. Here, we investigated the impact of individual antibiotics on the fecal microbiota in the context of an established EHEC mouse model using C. rodentium ϕstx2dact. The infection caused significant variations in the microbiota, leading to a transient increase in Enterobacteriaceae distinct from Citrobacter. However, these effects were minor compared to those observed for antibiotic treatments. Indeed, antibiotics that most efficiently cleared the infection also had the most detrimental effect on the fecal microbiota, causing a substantial reduction in microbial diversity. Conversely, antibiotics showing adverse effects or incomplete bacterial clearance had a reduced impact on microbiota composition and diversity. Taken together, our findings emphasize the delicate balance required to weigh the harmful effects of infection and antibiosis in treatment.
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Affiliation(s)
- Sabrina Mühlen
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Institute of Infectiology, University of Münster, Münster, Germany
- German Centre for Infection Research (DZIF), partner site HZI, Braunschweig, and associated site University of Münster, Münster, Germany
- Department of Molecular Immunology, Ruhr-University Bochum, Bochum, Germany
| | - Ann Kathrin Heroven
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Microbial Interactions and Processes, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Bettina Elxnat
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Silke Kahl
- Microbial Interactions and Processes, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Dietmar H. Pieper
- Microbial Interactions and Processes, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Petra Dersch
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Institute of Infectiology, University of Münster, Münster, Germany
- German Centre for Infection Research (DZIF), partner site HZI, Braunschweig, and associated site University of Münster, Münster, Germany
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8
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Bowser S, Melton-Celsa A, Chapartegui-González I, Torres AG. Efficacy of EHEC gold nanoparticle vaccines evaluated with the Shiga toxin-producing Citrobacter rodentium mouse model. Microbiol Spectr 2024; 12:e0226123. [PMID: 38047703 PMCID: PMC10783022 DOI: 10.1128/spectrum.02261-23] [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: 05/30/2023] [Accepted: 10/16/2023] [Indexed: 12/05/2023] Open
Abstract
IMPORTANCE Enterohemorrhagic Escherichia coli (EHEC) remains an important cause of diarrheal disease and complications worldwide, especially in children, yet there are no available vaccines for human use. Inadequate pre-clinical evaluation due to inconsistent animal models remains a major barrier to novel vaccine development. We demonstrate the usefulness of Stx2d-producing Citrobacter rodentium in assessing vaccine effectiveness because it more closely recapitulates human disease caused by EHEC.
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Affiliation(s)
- Sarah Bowser
- Department of Microbiology and Immunology, The University of Texas Medical Branch at Galveston, Galveston, Texas, USA
| | - Angela Melton-Celsa
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Itziar Chapartegui-González
- Department of Microbiology and Immunology, The University of Texas Medical Branch at Galveston, Galveston, Texas, USA
| | - Alfredo G. Torres
- Department of Microbiology and Immunology, The University of Texas Medical Branch at Galveston, Galveston, Texas, USA
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, USA
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9
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Fang F, Xue Y, Xu X, Fang D, Liu W, Zhong Y, Han J, Li Y, Tao Q, Lu R, Ma C, Kumar A, Wang D. L-glutamine protects against enterohemorrhagic Escherichia coli infection by inhibiting bacterial virulence and enhancing host defense concurrently. Microbiol Spectr 2023; 11:e0097523. [PMID: 37815335 PMCID: PMC10714755 DOI: 10.1128/spectrum.00975-23] [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: 03/07/2023] [Accepted: 08/24/2023] [Indexed: 10/11/2023] Open
Abstract
IMPORTANCE The type 3 secretion system (T3SS) was obtained in many Gram-negative bacterial pathogens, and it is crucial for their pathogenesis. Environmental signals were found to be involved in the expression regulation of T3SS, which was vital for successful bacterial infection in the host. Here, we discovered that L-glutamine (Gln), the most abundant amino acid in the human body, could repress enterohemorrhagic Escherichia coli (EHEC) T3SS expression via nitrogen metabolism and therefore had potential as an antivirulence agent. Our in vitro and in vivo evidence demonstrated that Gln could decline EHEC infection by attenuating bacterial virulence and enhancing host defense simultaneously. We repurpose Gln as a potential treatment for EHEC infection accordingly.
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Affiliation(s)
- Fang Fang
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Yunxin Xue
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Xuefang Xu
- State Key Laboratory of Infectious Disease Prevention and Control and National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China
| | - Dingli Fang
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Weijia Liu
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Ying Zhong
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Jinping Han
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Yunhe Li
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Qian Tao
- Department of Pathology, Women and Children's Hospital, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, Xiamen University, Xiamen, Fujian Province, China
| | - Rong Lu
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Cong Ma
- Department of Nephrology, Lishan Hospital, Anshan Central Hospital, Anshan, Liaoning Province, China
| | | | - Dai Wang
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
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10
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Wei X, Aggrawal A, Bond RF, Atwill ER. Low to Zero Concentrations of Airborne Bacterial Pathogens and Indicator E. coli in Proximity to Beef Cattle Feedlots in Imperial Valley, California. Microorganisms 2023; 11:microorganisms11020411. [PMID: 36838376 PMCID: PMC9961607 DOI: 10.3390/microorganisms11020411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/03/2023] [Accepted: 02/03/2023] [Indexed: 02/10/2023] Open
Abstract
This study characterized the effect of distance from beef cattle feedlots, environmental factors, and climate on the occurrence of airborne bacterial indicators and pathogens. Three hundred air samples were collected over 6 months from five feedlots, with each air sample comprising 6000 L of air. Air samples were processed onto TSB-enriched air filters, qPCR-screened, and then qPCR-confirmed for suspect positive colonies of E. coli O157, non-O157-Shiga-toxin-producing E. coli (STEC), Salmonella, and E. coli. Direct enumeration of E. coli was also collected. Although no bacterial pathogens were qPCR-confirmed for the 300 samples, E. coli was detected in 16.7% (50/300) of samples, with an overall mean concentration of 0.17 CFU/6000 L air. Logistic regression analyses revealed a higher odds of E. coli for samples in close proximity compared to >610 m (2000 ft) distance from feedlots, along with significant associations with meteorological factors, sampling hour of day, and the presence of a dust-generating activity such as plowing a field or nearby vehicular traffic. The lack of bacterial pathogen detection suggests airborne deposition from nearby feedlots may not be a significant mechanism of leafy green bacterial pathogen contamination; the result of our study provides data to inform future revisions of produce-safety guidance.
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11
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Fang X, Nong K, Wang Z, Jin Y, Gao F, Zeng Q, Wang X, Zhang H. Human cathelicidin LL-37 exerts amelioration effects against EHEC O157:H7 infection regarding inflammation, enteric dysbacteriosis, and impairment of gut barrier function. Peptides 2023; 159:170903. [PMID: 36370932 DOI: 10.1016/j.peptides.2022.170903] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 11/04/2022] [Accepted: 11/07/2022] [Indexed: 11/11/2022]
Abstract
Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 infection impairs intestinal barrier function, causing intestinal inflammation and enteric dysbacteriosis. The human cathelicidin LL-37 can regulate excessive inflammatory responses, barrier function, and balance the intestinal microbial community; however, little is known about its effects on inflammation, intestinal barrier function, and microbiota disorders in EHEC O157:H7-infected mice. In this study, we investigated the protective effect of LL-37 against EHEC O157:H7 infection and elucidated the underlying mechanism using a mouse model. LL-37 treatment was found to inhibit body weight loss, restore edema and destruction of the intestinal villi, and significantly reduce epithelial apoptosis (P < 0.05) in EHEC O157:H7-infected mice. Furthermore, inflammatory infiltration of macrophages and neutrophils into the jejunum and colon was significantly decreased (P < 0.05). LL-37 significantly downregulated the production of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) (P < 0.05) and upregulated the anti-inflammatory cytokine (IL-10) during EHEC O157:H7 infection. LL-37 increased the expression of tight junction proteins (ZO-1, ZO-2, claudin-1, and occludin), which are associated with intestinal barrier function, and had a positive effect on EHEC O157:H7-induced microbial disorders, particularly in terms of the inflammation-related microbiota. LL-37 also significantly decreased the E. coli load in the liver and spleen (P < 0.01) and restored the structure of the liver and kidney. Taken together, LL-37 conferred protection in a EHEC O157:H7-induced mouse model by reducing intestinal inflammation, enhancing intestinal barrier function, and restoring the balance of the intestinal microbiota, which indicates the therapeutic potential of LL-37 against pathogen infection.
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Affiliation(s)
- Xin Fang
- College of Animal Science and Technology of Hainan University, Haikou, Hainan 570228, China
| | - Keyi Nong
- College of Animal Science and Technology of Hainan University, Haikou, Hainan 570228, China
| | - Zihan Wang
- College of Animal Science and Technology of Hainan University, Haikou, Hainan 570228, China
| | - Yuanli Jin
- College of Animal Science and Technology of Hainan University, Haikou, Hainan 570228, China
| | - Feng Gao
- College of Animal Science and Technology of Hainan University, Haikou, Hainan 570228, China
| | - Qiuyu Zeng
- College of Animal Science and Technology of Hainan University, Haikou, Hainan 570228, China
| | - Xuemei Wang
- College of Animal Science and Technology of Hainan University, Haikou, Hainan 570228, China
| | - Haiwen Zhang
- College of Animal Science and Technology of Hainan University, Haikou, Hainan 570228, China.
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12
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Nakanishi K, Takase T, Ohira Y, Ida R, Mogi N, Kikuchi Y, Matsuda M, Kurohane K, Akimoto Y, Hayakawa J, Kawakami H, Niwa Y, Kobayashi H, Umemoto E, Imai Y. Prevention of Shiga toxin 1-caused colon injury by plant-derived recombinant IgA. Sci Rep 2022; 12:17999. [PMID: 36289440 PMCID: PMC9606113 DOI: 10.1038/s41598-022-22851-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 10/20/2022] [Indexed: 01/24/2023] Open
Abstract
Immunoglobulin A (IgA) is a candidate antibody for oral passive immunization against mucosal pathogens like Shiga toxin-producing Escherichia coli (STEC). We previously established a mouse IgG monoclonal antibody (mAb) neutralizing Shiga toxin 1 (Stx1), a bacterial toxin secreted by STEC. We designed cDNA encoding an anti-Stx1 antibody, in which variable regions were from the IgG mAb and all domains of the heavy chain constant region from a mouse IgA mAb. Considering oral administration, we expressed the cDNA in a plant expression system aiming at the production of enough IgA at low cost. The recombinant-IgA expressed in Arabidopsis thaliana formed the dimeric IgA, bound to the B subunit of Stx1, and neutralized Stx1 toxicity to Vero cells. Colon injury was examined by exposing BALB/c mice to Stx1 via the intrarectal route. Epithelial cell death, loss of crypt and goblet cells from the distal colon were observed by electron microscopy. A loss of secretory granules containing MUC2 mucin and activation of caspase-3 were observed by immunohistochemical methods. Pretreatment of Stx1 with the plant-based recombinant IgA completely suppressed caspase-3 activation and loss of secretory granules. The results indicate that a plant-based recombinant IgA prevented colon damage caused by Stx1 in vivo.
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Affiliation(s)
- Katsuhiro Nakanishi
- grid.469280.10000 0000 9209 9298Laboratory of Microbiology and Immunology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka City, Shizuoka 422-8526 Japan
| | - Taichi Takase
- grid.469280.10000 0000 9209 9298Laboratory of Microbiology and Immunology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka City, Shizuoka 422-8526 Japan
| | - Yuya Ohira
- grid.469280.10000 0000 9209 9298Laboratory of Microbiology and Immunology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka City, Shizuoka 422-8526 Japan
| | - Ryota Ida
- grid.469280.10000 0000 9209 9298Laboratory of Microbiology and Immunology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka City, Shizuoka 422-8526 Japan
| | - Noriko Mogi
- grid.469280.10000 0000 9209 9298Laboratory of Microbiology and Immunology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka City, Shizuoka 422-8526 Japan
| | - Yuki Kikuchi
- grid.469280.10000 0000 9209 9298Laboratory of Microbiology and Immunology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka City, Shizuoka 422-8526 Japan
| | - Minami Matsuda
- grid.469280.10000 0000 9209 9298Laboratory of Microbiology and Immunology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka City, Shizuoka 422-8526 Japan
| | - Kohta Kurohane
- grid.469280.10000 0000 9209 9298Laboratory of Microbiology and Immunology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka City, Shizuoka 422-8526 Japan
| | - Yoshihiro Akimoto
- grid.411205.30000 0000 9340 2869Department of Anatomy, Kyorin University School of Medicine, Mitaka, Tokyo, 181-8611 Japan
| | - Junri Hayakawa
- grid.411205.30000 0000 9340 2869Laboratory for Electron Microscopy, Kyorin University School of Medicine, Mitaka, Tokyo, 181-8611 Japan
| | - Hayato Kawakami
- grid.411205.30000 0000 9340 2869Department of Anatomy, Kyorin University School of Medicine, Mitaka, Tokyo, 181-8611 Japan
| | - Yasuo Niwa
- grid.469280.10000 0000 9209 9298Laboratory of Plant Molecular Improvement, Graduate Division of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka City, Shizuoka 422-8526 Japan
| | - Hirokazu Kobayashi
- grid.469280.10000 0000 9209 9298Laboratory of Plant Molecular Improvement, Graduate Division of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka City, Shizuoka 422-8526 Japan
| | - Eiji Umemoto
- grid.469280.10000 0000 9209 9298Laboratory of Microbiology and Immunology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka City, Shizuoka 422-8526 Japan
| | - Yasuyuki Imai
- grid.469280.10000 0000 9209 9298Laboratory of Microbiology and Immunology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka City, Shizuoka 422-8526 Japan
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13
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Tsutsuki H, Zhang T, Yahiro K, Toyomoto T, Sawa T. Non-canonical inflammasome activation analysis in a mouse model of Citrobacter rodentium infection. STAR Protoc 2022; 3:101741. [PMID: 36201318 PMCID: PMC9535312 DOI: 10.1016/j.xpro.2022.101741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/02/2022] [Accepted: 09/09/2022] [Indexed: 11/07/2022] Open
Abstract
Infection of mice with Citrobacter rodentium is a useful model for studying the pathogenicity of enteropathogenic and enterohemorrhagic Escherichia coli, pathogens that have a close association with humans. Here, we provide a protocol detailing the approaches for non-canonical inflammasome analysis in a mouse model of C. rodentium infection, including preparation of bacteria, oral administration of bacteria to mice, counting colony-forming units to quantify bacterial colonization, and analysis of expression and activation of inflammasome-related factors. For complete details on the use and execution of this protocol, please refer to Tsutsuki et al. (2022).
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Affiliation(s)
- Hiroyasu Tsutsuki
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan,Corresponding author
| | - Tianli Zhang
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
| | - Kinnosuke Yahiro
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan
| | - Touya Toyomoto
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
| | - Tomohiro Sawa
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan,Corresponding author
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14
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Zeng Y, Jiang M, Robinson S, Peng Z, Chonira V, Simeon R, Tzipori S, Zhang J, Chen Z. A Multi-Specific DARPin Potently Neutralizes Shiga Toxin 2 via Simultaneous Modulation of Both Toxin Subunits. Bioengineering (Basel) 2022; 9:511. [PMID: 36290479 PMCID: PMC9598796 DOI: 10.3390/bioengineering9100511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/19/2022] [Accepted: 09/20/2022] [Indexed: 11/25/2022] Open
Abstract
Shiga toxin-producing E. coli (STEC) is a common cause of bloody diarrhea. The pathology of STEC infection derives from two exotoxins-Shiga toxin 1 (Stx1) and Shiga toxin 2 (Stx2)-that are secreted by STEC in the gut, from where they are systemically absorbed, causing severe kidney damage leading to hemolytic uremic syndrome (HUS). Currently, there is no effective treatment for HUS, and only supportive care is recommended. We report the engineering of a panel of designed ankyrin repeat proteins (DARPin) with potent neutralization activity against Stx2a, the major subtype associated with HUS. The best dimeric DARPin, SD5, created via a combination of directed evolution and rational design, neutralizes Stx2a with a half maximal effective concentration (EC50) of 0.61 nM in vitro. The two monomeric DARPin constituents of SD5 exhibit complementary functions-SHT targets the enzymatic A subunit of Stx2a and inhibits the toxin's catalytic activity, while DARPin #3 binds the B subunit, based on the cryo-EM study, and induces a novel conformational change in the B subunit that distorts its five-fold symmetry and presumably interferes with toxin attachment to target cells. SD5 was fused to an albumin-binding DARPin, and the resulting trimeric DARPin DA1-SD5 efficiently protects mice in a toxin challenge model, pointing to a high potential of this DARPin as a therapeutic for STEC infection. Finally, the unprecedented toxin conformational change induced by DARPin #3 represents a novel mode of action for neutralizing Stx2 toxicity and reveals new targets for future drug development.
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Affiliation(s)
- Yu Zeng
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, 8847 Riverside Pkwy, Bryan, TX 77807, USA
| | - Mengqiu Jiang
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Blvd., College Station, TX 77843, USA
| | - Sally Robinson
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, 200 Westboro Rd, North Grafton, MA 01536, USA
| | - Zeyu Peng
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, 8847 Riverside Pkwy, Bryan, TX 77807, USA
| | - Vikas Chonira
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, 8847 Riverside Pkwy, Bryan, TX 77807, USA
| | - Rudo Simeon
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, 8847 Riverside Pkwy, Bryan, TX 77807, USA
| | - Saul Tzipori
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, 200 Westboro Rd, North Grafton, MA 01536, USA
| | - Junjie Zhang
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Blvd., College Station, TX 77843, USA
| | - Zhilei Chen
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, 8847 Riverside Pkwy, Bryan, TX 77807, USA
- Interdisciplinary Graduate Program in Genetics, Texas A&M University, 300 Olsen Blvd., College Station, TX 77843, USA
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15
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Comparison of Selenium-Enriched Lactobacillusparacasei, Selenium-Enriched Yeast, and Selenite for the Alleviation of DSS-Induced Colitis in Mice. Nutrients 2022; 14:nu14122433. [PMID: 35745163 PMCID: PMC9231187 DOI: 10.3390/nu14122433] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/03/2022] [Accepted: 06/10/2022] [Indexed: 02/04/2023] Open
Abstract
Patients with inflammatory bowel disease (IBD) have been found to have decreased immune function. Selenium (Se) is an essential trace element that is beneficial for human health, which has a significant stimulating effect on immune function. We compared the effects of different Se forms on the alleviation of colitis in DSS-induced mice. Moreover, we also aimed to determine whether Se-enriched Lactobacillus paracasei CCFM 1089 could be used as a new organic Se supplement. Different Se supplements (Se-enriched L. paracasei CCFM 1089, Se-enriched yeast and sodium selenite) were given to Se-deficient mice suffering from colitis. Se-enriched L. paracasei CCFM 1089, which is based on selenocysteine (SeCys), had similar effects in terms of reducing oxidative stress and inhibiting pro-inflammatory factors to Se-enriched yeast; however, selenase activity in the Se-enriched L. paracasei CCFM 1089-treated mice was higher than that in other treatment groups. In addition, Se-enriched L. paracasei CCFM 1089 could better protect the intestinal mucosa, which increased the expression of tight junction proteins (ZO-1 and occludin) in mice. Thus Se-enriched L. paracasei CCFM 1089 was shown to alleviate IBD, suggesting that it has potential as a good organic Se supplement.
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16
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Tsutsuki H, Zhang T, Yahiro K, Ono K, Fujiwara Y, Iyoda S, Wei FY, Monde K, Seto K, Ohnishi M, Oshiumi H, Akaike T, Sawa T. Subtilase cytotoxin from Shiga-toxigenic Escherichia coli impairs the inflammasome and exacerbates enteropathogenic bacterial infection. iScience 2022; 25:104050. [PMID: 35345462 PMCID: PMC8957020 DOI: 10.1016/j.isci.2022.104050] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/08/2022] [Accepted: 03/08/2022] [Indexed: 01/18/2023] Open
Abstract
Subtilase cytotoxin (SubAB) is an AB5 toxin mainly produced by the locus of enterocyte effacement-negative Shiga-toxigenic Escherichia coli (STEC) strain such as O113:H21, yet the contribution of SubAB to STEC infectious disease is unclear. We found that SubAB reduced activation of the STEC O113:H21 infection-induced non-canonical NLRP3 inflammasome and interleukin (IL)-1β and IL-18 production in murine macrophages. Downstream of lipopolysaccharide signaling, SubAB suppressed caspase-11 expression by inhibiting interferon-β/STAT1 signaling, followed by disrupting formation of the NLRP3/caspase-1 assembly. These inhibitions were regulated by PERK/IRE1α-dependent endoplasmic reticulum (ER) stress signaling initiated by cleavage of the host ER chaperone BiP by SubAB. Our murine model of SubAB-producing Citrobacter rodentium demonstrated that SubAB promoted C. rodentium proliferation and worsened symptoms such as intestinal hyperplasia and diarrhea. These findings highlight the inhibitory effect of SubAB on the NLRP3 inflammasome via ER stress, which may be associated with STEC survival and infectious disease pathogenicity in hosts. SubAB from STEC inhibits inflammasome activation and IL-1β/IL-18 production SubAB prevents caspase-11 expression via IRE1α/PERK-dependent inhibition of STAT1 SubAB reduces LPS-induced pro-IL-1β production via IRE1α/PERK-dependent pathway SubAB promotes C. rodentium survival in mouse colon and facilitates the infection
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Affiliation(s)
- Hiroyasu Tsutsuki
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
- Corresponding author
| | - Tianli Zhang
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
| | - Kinnosuke Yahiro
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan
| | - Katsuhiko Ono
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
| | - Yukio Fujiwara
- Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, Chuo-ku, Kumamoto 860-8556, Japan
| | - Sunao Iyoda
- Department of Bacteriology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Fan-Yan Wei
- Department of Modomics Biology and Medicine, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Kazuaki Monde
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
| | - Kazuko Seto
- Quality Assurance Unit, Division of Planning, Osaka Institute of Public Health, 1-3-69 Nakamichi, Higashinari-ku, Osaka 537-0025, Japan
| | - Makoto Ohnishi
- Department of Bacteriology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Hiroyuki Oshiumi
- Department of Immunology, Graduate School of Medical Sciences, Kumamoto University, Chuo-ku, Kumamoto 860-8556, Japan
| | - Takaaki Akaike
- Department of Environmental Medicine and Molecular Toxicology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Tomohiro Sawa
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
- Corresponding author
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17
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Citrobacter rodentium(ϕStx2dact), a murine infection model for enterohemorrhagic Escherichia coli. Curr Opin Microbiol 2022; 65:183-190. [PMID: 34929548 PMCID: PMC9069446 DOI: 10.1016/j.mib.2021.11.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 11/17/2021] [Accepted: 11/29/2021] [Indexed: 02/03/2023]
Abstract
The formation of attaching and effacing (A/E) lesions on intestinal epithelium, combined with Shiga toxin production, are hallmarks of enterohemorrhagic Escherichia coli (EHEC) infection that can lead to lethal hemolytic uremic syndrome. Although an animal infection model that fully recapitulates human disease remains elusive, mice orally infected with Citrobacter rodentium(ϕStx2dact), a natural murine pathogen lysogenized with an EHEC-derived Shiga toxin 2-producing bacteriophage, develop intestinal A/E lesions and toxin-dependent systemic disease. This model has facilitated investigation of how: (A) phage gene expression and prophage induction contribute to disease and are potentially triggered by antibiotic treatment; (B) virulence gene expression is altered by microbiota and the colonic metabolomic milieu; and (C) innate immune signaling is affected by Stx. Thus, the model provides a unique tool for accessing diverse aspects of EHEC pathogenesis.
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18
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Koeppel MB, Glaser J, Baumgartner T, Spriewald S, Gerlach RG, von Armansperg B, Leong JM, Stecher B. Scalable Reporter Assays to Analyze the Regulation of stx2 Expression in Shiga Toxin-Producing Enteropathogens. Toxins (Basel) 2021; 13:toxins13080534. [PMID: 34437405 PMCID: PMC8402550 DOI: 10.3390/toxins13080534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 12/02/2022] Open
Abstract
Stx2 is the major virulence factor of EHEC and is associated with an increased risk for HUS in infected patients. The conditions influencing its expression in the intestinal tract are largely unknown. For optimal management and treatment of infected patients, the identification of environmental conditions modulating Stx2 levels in the human gut is of central importance. In this study, we established a set of chromosomal stx2 reporter assays. One system is based on superfolder GFP (sfGFP) using a T7 polymerase/T7 promoter-based amplification loop. This reporter can be used to analyze stx2 expression at the single-cell level using FACSs and fluorescence microscopy. The other system is based on the cytosolic release of the Gaussia princeps luciferase (gluc). This latter reporter proves to be a highly sensitive and scalable reporter assay that can be used to quantify reporter protein in the culture supernatant. We envision that this new set of reporter tools will be highly useful to comprehensively analyze the influence of environmental and host factors, including drugs, small metabolites and the microbiota, on Stx2 release and thereby serve the identification of risk factors and new therapies in Stx-mediated pathologies.
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Affiliation(s)
- Martin B. Koeppel
- Max-von-Pettenkofer Institute, LMU Munich, Pettenkoferstr. 9a, 80336 Munich, Germany; (J.G.); (T.B.); (S.S.); (B.v.A.)
- German Center for Infection Research (DZIF), Partner Site LMU Munich, 80336 Munich, Germany
- Correspondence: (M.B.K.); (B.S.)
| | - Jana Glaser
- Max-von-Pettenkofer Institute, LMU Munich, Pettenkoferstr. 9a, 80336 Munich, Germany; (J.G.); (T.B.); (S.S.); (B.v.A.)
- German Center for Infection Research (DZIF), Partner Site LMU Munich, 80336 Munich, Germany
| | - Tobias Baumgartner
- Max-von-Pettenkofer Institute, LMU Munich, Pettenkoferstr. 9a, 80336 Munich, Germany; (J.G.); (T.B.); (S.S.); (B.v.A.)
- German Center for Infection Research (DZIF), Partner Site LMU Munich, 80336 Munich, Germany
| | - Stefanie Spriewald
- Max-von-Pettenkofer Institute, LMU Munich, Pettenkoferstr. 9a, 80336 Munich, Germany; (J.G.); (T.B.); (S.S.); (B.v.A.)
- German Center for Infection Research (DZIF), Partner Site LMU Munich, 80336 Munich, Germany
| | - Roman G. Gerlach
- Mikrobiologisches Institut-Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Wasserturmstraße 3/5, 91054 Erlangen, Germany;
| | - Benedikt von Armansperg
- Max-von-Pettenkofer Institute, LMU Munich, Pettenkoferstr. 9a, 80336 Munich, Germany; (J.G.); (T.B.); (S.S.); (B.v.A.)
- German Center for Infection Research (DZIF), Partner Site LMU Munich, 80336 Munich, Germany
| | - John M. Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Ave, Boston, MA 02111, USA;
| | - Bärbel Stecher
- Max-von-Pettenkofer Institute, LMU Munich, Pettenkoferstr. 9a, 80336 Munich, Germany; (J.G.); (T.B.); (S.S.); (B.v.A.)
- German Center for Infection Research (DZIF), Partner Site LMU Munich, 80336 Munich, Germany
- Correspondence: (M.B.K.); (B.S.)
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19
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Flowers LJ, Hu S, Shrestha A, Martinot AJ, Leong JM, Osburne MS. Citrobacter rodentium Lysogenized with a Shiga Toxin-Producing Phage: A Murine Model for Shiga Toxin-Producing E. coli Infection. Methods Mol Biol 2021; 2291:381-397. [PMID: 33704765 DOI: 10.1007/978-1-0716-1339-9_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
Shiga toxin-producing E. coli (STEC) is a common foodborne pathogen in developed countries. STEC generates "attaching and effacing" (AE) lesions on colonic epithelium, characterized by effacement of microvilli and the formation of actin "pedestals" beneath intimately attached bacteria. In addition, STEC are lysogenized with a phage that, upon induction, can produce potent Shiga toxins (Stx), potentially leading to both hemorrhagic colitis and hemolytic uremic syndrome. Investigation of the pathogenesis of this disease has been challenging because STEC does not readily colonize conventional mice.Citrobacter rodentium (CR) is a related mouse pathogen that also generates AE lesions. Whereas CR does not produce Stx, a murine model for STEC utilizes CR lysogenized with an E. coli-derived Stx phage, generating CR(Φstx), which both colonizes conventional mice and readily gives rise to systemic disease. We present here key methods for the use of CR(Φstx) infection as a highly predictable murine model for infection and disease by STEC. Importantly, we detail CR(Φstx) inoculation by feeding, determination of pathogen colonization, production of phage and toxin, and assessment of intestinal and renal pathology. These methods provide a framework for studying STEC-mediated systemic disease that may aid in the development of efficacious therapeutics.
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Affiliation(s)
- Laurice J Flowers
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA.,Tufts University Graduate School in Biomedical Sciences, Boston, MA, USA.,Department of Dermatology, University of Pennsylvania, Philadelphia, PA, USA
| | - Shenglan Hu
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA.,Institute of Animal Science, Guangdong Academy of Agricultural Sciences, State Key Laboratory of Livestock and Poultry Breeding, Key Laboratory of Animal Nutrition and Feed Science in South China, Ministry of Agriculture and Rural Affairs, Guangdong Key Laboratory of Animal Breeding, Guangzhou, China
| | - Anishma Shrestha
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA
| | - Amanda J Martinot
- Department of Infectious Diseases and Global Health, Tufts Cummings School of Veterinary Medicine, North Grafton, MA, USA
| | - John M Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA
| | - Marcia S Osburne
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA.
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20
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Liu Y, Tian S, Thaker H, Dong M. Shiga Toxins: An Update on Host Factors and Biomedical Applications. Toxins (Basel) 2021; 13:222. [PMID: 33803852 PMCID: PMC8003205 DOI: 10.3390/toxins13030222] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/13/2021] [Accepted: 03/15/2021] [Indexed: 12/18/2022] Open
Abstract
Shiga toxins (Stxs) are classic bacterial toxins and major virulence factors of toxigenic Shigella dysenteriae and enterohemorrhagic Escherichia coli (EHEC). These toxins recognize a glycosphingolipid globotriaosylceramide (Gb3/CD77) as their receptor and inhibit protein synthesis in cells by cleaving 28S ribosomal RNA. They are the major cause of life-threatening complications such as hemolytic uremic syndrome (HUS), associated with severe cases of EHEC infection, which is the leading cause of acute kidney injury in children. The threat of Stxs is exacerbated by the lack of toxin inhibitors and effective treatment for HUS. Here, we briefly summarize the Stx structure, subtypes, in vitro and in vivo models, Gb3 expression and HUS, and then introduce recent studies using CRISPR-Cas9-mediated genome-wide screens to identify the host cell factors required for Stx action. We also summarize the latest progress in utilizing and engineering Stx components for biomedical applications.
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Affiliation(s)
- Yang Liu
- Department of Nephrology, The First Hospital of Jilin University, Changchun 130021, China
- Department of Urology, Boston Children’s Hospital, Boston, MA 02115, USA; (S.T.); (H.T.)
- Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
| | - Songhai Tian
- Department of Urology, Boston Children’s Hospital, Boston, MA 02115, USA; (S.T.); (H.T.)
- Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
| | - Hatim Thaker
- Department of Urology, Boston Children’s Hospital, Boston, MA 02115, USA; (S.T.); (H.T.)
- Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
| | - Min Dong
- Department of Urology, Boston Children’s Hospital, Boston, MA 02115, USA; (S.T.); (H.T.)
- Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
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21
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Naïli I, Gardette M, Garrivier A, Daniel J, Desvaux M, Pizza M, Gobert A, Marchal T, Loukiadis E, Jubelin G. Interplay between enterohaemorrhagic Escherichia coli and nitric oxide during the infectious process. Emerg Microbes Infect 2021; 9:1065-1076. [PMID: 32459575 PMCID: PMC7336997 DOI: 10.1080/22221751.2020.1768804] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Enterohaemorrhagic Escherichia coli (EHEC) are bacterial pathogens responsible for life-threatening diseases in humans such as bloody diarrhoea and the hemolytic and uremic syndrome. To date, no specific therapy is available and treatments remain essentially symptomatic. In recent years, we demonstrated in vitro that nitric oxide (NO), a major mediator of the intestinal immune response, strongly represses the synthesis of the two cardinal virulence factors in EHEC, namely Shiga toxins (Stx) and the type III secretion system, suggesting NO has a great potential to protect against EHEC infection. In this study, we investigated the interplay between NO and EHEC in vivo using mouse models of infection. Using a NO-sensing reporter strain, we determined that EHEC sense NO in the gut of infected mice. Treatment of infected mice with a specific NOS inhibitor increased EHEC adhesion to the colonic mucosa but unexpectedly decreased Stx activity in the gastrointestinal tract, protecting mice from renal failure. Taken together, our data indicate that NO can have both beneficial and detrimental consequences on the outcome of an EHEC infection, and underline the importance of in vivo studies to increase our knowledge in host–pathogen interactions.
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Affiliation(s)
- Ilham Naïli
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France.,GSK, Siena, Italy
| | - Marion Gardette
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France.,Université de Lyon, CNRS, INRAE, Université Claude Bernard Lyon 1, VetAgro Sup, Laboratoire d'Ecologie Microbienne, F-63280 Marcy l'Etoile, France
| | - Annie Garrivier
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
| | - Julien Daniel
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
| | - Mickaël Desvaux
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
| | | | - Alain Gobert
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
| | - Thierry Marchal
- VetAgro Sup, Laboratoire vétérinaire d'histopathologie, F-63280 Marcy-l'Etoile, France
| | - Estelle Loukiadis
- Université de Lyon, CNRS, INRAE, Université Claude Bernard Lyon 1, VetAgro Sup, Laboratoire d'Ecologie Microbienne, F-63280 Marcy l'Etoile, France.,VetAgro Sup, Laboratoire national de référence des E. coli, F-63280 Marcy-l'Etoile, France
| | - Grégory Jubelin
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
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22
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Havira MS, Ta A, Kumari P, Wang C, Russo AJ, Ruan J, Rathinam VA, Vanaja SK. Shiga toxin suppresses noncanonical inflammasome responses to cytosolic LPS. Sci Immunol 2020; 5:5/53/eabc0217. [PMID: 33246946 DOI: 10.1126/sciimmunol.abc0217] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 10/02/2020] [Accepted: 11/06/2020] [Indexed: 12/12/2022]
Abstract
Inflammatory caspase-dependent cytosolic lipopolysaccharide (LPS) sensing is a critical arm of host defense against bacteria. How pathogens overcome this pathway to establish infections is largely unknown. Enterohemorrhagic Escherichia coli (EHEC) is a clinically important human pathogen causing hemorrhagic colitis and hemolytic uremic syndrome. We found that a bacteriophage-encoded virulence factor of EHEC, Shiga toxin (Stx), suppresses caspase-11-mediated activation of the cytosolic LPS sensing pathway. Stx was essential and sufficient to inhibit pyroptosis and interleukin-1 (IL-1) responses elicited specifically by cytosolic LPS. The catalytic activity of Stx was necessary for suppression of inflammasome responses. Stx impairment of inflammasome responses to cytosolic LPS occurs at the level of gasdermin D activation. Stx also suppresses inflammasome responses in vivo after LPS challenge and bacterial infection. Overall, this study assigns a previously undescribed inflammasome-subversive function to a well-known bacterial toxin, Stx, and reveals a new phage protein-based pathogen blockade of cytosolic immune surveillance.
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Affiliation(s)
- Morena S Havira
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Ave., Farmington, CT 06030, USA
| | - Atri Ta
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Ave., Farmington, CT 06030, USA
| | - Puja Kumari
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Ave., Farmington, CT 06030, USA
| | - Chengliang Wang
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Ave., Farmington, CT 06030, USA
| | - Ashley J Russo
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Ave., Farmington, CT 06030, USA
| | - Jianbin Ruan
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Ave., Farmington, CT 06030, USA
| | - Vijay A Rathinam
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Ave., Farmington, CT 06030, USA
| | - Sivapriya Kailasan Vanaja
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Ave., Farmington, CT 06030, USA.
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23
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Riebisch AK, Mühlen S. Attaching and effacing pathogens: the effector ABC of immune subversion. Future Microbiol 2020; 15:945-958. [PMID: 32716209 DOI: 10.2217/fmb-2019-0274] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The innate immune response resembles an essential barrier to bacterial infection. Many bacterial pathogens have, therefore, evolved mechanisms to evade from or subvert the host immune response in order to colonize, survive and multiply. The attaching and effacing pathogens enteropathogenic Escherichia coli, enterohaemorrhagic E. coli, Escherichia albertii and Citrobacter rodentium are Gram-negative extracellular gastrointestinal pathogens. They use a type III secretion system to inject effector proteins into the host cell to manipulate a variety of cellular processes. Over the last decade, considerable progress was made in identifying and characterizing the effector proteins of attaching and effacing pathogens that are involved in the inhibition of innate immune signaling pathways, in determining their host cell targets and elucidating the mechanisms they employ. Their functions will be reviewed here.
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Affiliation(s)
- Anna Katharina Riebisch
- Systems-Oriented Immunology & Inflammation Research, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany.,Institute for Molecular & Clinical Immunology, Otto von Guericke University Magdeburg, 39106 Magdeburg, Germany.,Department of Molecular Immunology, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Sabrina Mühlen
- Institute for Infectiology, University of Münster, 48149 Münster, Germany.,German Center for Infection Research (DZIF), Associated Site University of Münster, 48149 Münster, Germany
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24
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Slater SL, Frankel G. Advances and Challenges in Studying Type III Secretion Effectors of Attaching and Effacing Pathogens. Front Cell Infect Microbiol 2020; 10:337. [PMID: 32733819 PMCID: PMC7358347 DOI: 10.3389/fcimb.2020.00337] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 06/04/2020] [Indexed: 12/24/2022] Open
Affiliation(s)
- Sabrina L Slater
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Gad Frankel
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
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25
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Kumar A, Russell RM, Pifer R, Menezes-Garcia Z, Cuesta S, Narayanan S, MacMillan JB, Sperandio V. The Serotonin Neurotransmitter Modulates Virulence of Enteric Pathogens. Cell Host Microbe 2020; 28:41-53.e8. [PMID: 32521224 DOI: 10.1016/j.chom.2020.05.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/30/2020] [Accepted: 05/05/2020] [Indexed: 02/06/2023]
Abstract
The gut-brain axis is crucial to microbial-host interactions. The neurotransmitter serotonin is primarily synthesized in the gastrointestinal (GI) tract, where it is secreted into the lumen and subsequently removed by the serotonin transporter, SERT. Here, we show that serotonin decreases virulence gene expression by enterohemorrhagic E. coli (EHEC) and Citrobacter rodentium, a murine model for EHEC. The membrane-bound histidine sensor kinase, CpxA, is a bacterial serotonin receptor. Serotonin induces dephosphorylation of CpxA, which inactivates the transcriptional factor CpxR controlling expression of virulence genes, notably those within the locus of enterocyte effacement (LEE). Increasing intestinal serotonin by genetically or pharmacologically inhibiting SERT decreases LEE expression and reduces C. rodentium loads. Conversely, inhibiting serotonin synthesis increases pathogenesis and decreases host survival. As other enteric bacteria contain CpxA, this signal exploitation may be engaged by other pathogens. Additionally, repurposing serotonin agonists to inhibit CpxA may represent a potential therapeutic intervention for enteric bacteria.
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Affiliation(s)
- Aman Kumar
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Regan M Russell
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Reed Pifer
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Zelia Menezes-Garcia
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Santiago Cuesta
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sanjeev Narayanan
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA
| | - John B MacMillan
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Vanessa Sperandio
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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26
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l-Arginine sensing regulates virulence gene expression and disease progression in enteric pathogens. Proc Natl Acad Sci U S A 2020; 117:12387-12393. [PMID: 32409599 DOI: 10.1073/pnas.1919683117] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Microbiota, host and dietary metabolites/signals compose the rich gut chemical environment, which profoundly impacts virulence of enteric pathogens. Enterohemorrhagic Escherichia coli (EHEC) engages a syringe-like machinery named type-III secretion system (T3SS) to inject effectors within host cells that lead to intestinal colonization and disease. We previously conducted a high-throughput screen to identify metabolic pathways that affect T3SS expression. Here we show that in the presence of arginine, the arginine sensor ArgR, identified through this screen, directly activates expression of the genes encoding the T3SS. Exogenously added arginine induces EHEC virulence gene expression in vitro. Congruently, a mutant deficient in arginine transport (ΔartP) had decreased virulence gene expression. ArgR also augments murine disease caused by Citrobacter rodentium, which is a murine pathogen extensively employed as a surrogate animal model for EHEC. The source of arginine sensed by C. rodentium is not dietary. At the peak of C. rodentium infection, increased arginine concentration in the colon correlated with down-regulation of the host SLC7A2 transporter. This increase in the concentration of colonic arginine promotes virulence gene expression in C. rodentium Arginine is an important modulator of the host immune response to pathogens. Here we add that arginine also directly impacts bacterial virulence. These findings suggest that a delicate balance between host and pathogen responses to arginine occur during disease progression.
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27
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Variations in microbiota composition of laboratory mice influence Citrobacter rodentium infection via variable short-chain fatty acid production. PLoS Pathog 2020; 16:e1008448. [PMID: 32208465 PMCID: PMC7141690 DOI: 10.1371/journal.ppat.1008448] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 04/08/2020] [Accepted: 03/01/2020] [Indexed: 01/08/2023] Open
Abstract
The composition of the intestinal microbiota influences the outcome of enteric infections in human and mice. However, the role of specific members and their metabolites contributing to disease severity is largely unknown. Using isogenic mouse lines harboring distinct microbiota communities, we observed highly variable disease kinetics of enteric Citrobacter rodentium colonization after infection. Transfer of communities from susceptible and resistant mice into germ-free mice verified that the varying susceptibilities are determined by microbiota composition. The strongest differences in colonization were observed in the cecum and could be maintained in vitro by coculturing cecal bacteria with C. rodentium. Cohousing of animals as well as the transfer of cultivable bacteria from resistant to susceptible mice led to variable outcomes in the recipient mice. Microbiome analysis revealed that a higher abundance of butyrate-producing bacteria was associated with the resistant phenotype. Quantification of short-chain fatty acid (SCFA) levels before and after infection revealed increased concentrations of acetate, butyrate and propionate in mice with delayed colonization. Addition of physiological concentrations of butyrate, but not of acetate and/or propionate strongly impaired growth of C. rodentium in vitro. In vivo supplementation of susceptible, antibiotic-treated and germ-free mice with butyrate led to the same level of protection, notably only when cecal butyrate concentration reached a concentration higher than 50 nmol/mg indicating a critical threshold for protection. In the recent years, commensal-derived primary and secondary bacterial metabolites emerged as potent modulators of hosts susceptibility to infection. Our results provide evidence that variations in SCFA production in mice fed fibre-rich chow-based diets modulate susceptibility to colonization with Enterobacteriaceae not only in antibiotic-disturbed ecosystems but even in undisturbed microbial communities. These findings emphasise the need for microbiota normalization across laboratory mouse lines for infection experiments with the model-pathogen C. rodentium independent of investigations of diet and antibiotic usage. The distinct composition of the gut microbiota in each individual results in variable metabolic activity and output of these communities, which influences the host, including resistance to enteric pathogens. Lack of reproducibility in biomedical research is nowadays frequently attributed to the microbiota, but little is known about which specific members and metabolites contribute to disease severity. Here, we use genetically identical mouse lines with variable microbiota compositions on a standardized diet and observed highly variable colonization with the enteric pathogen Citrobacter rodentium without antibiotics intervention. We found the same differences in formerly germ-free animals harbouring the respective donors microbiota and also in vitro by coculturing cecal bacteria from resistant and susceptible animals with C. rodentium showing that the phenotype is fully dependent on differences in the microbiota. We analysed the microbiome composition and found a higher abundance of butyrate-producing bacteria as well as increased levels of butyrate in resistant mice. By supplementation of susceptible and germ-free animals with butyrate, we could significantly lower the levels of colonization highlighting that commensal-derived primary and secondary bacterial metabolites are highly variable between laboratory animals from different vendors and are potent modulators of hosts susceptibility to infection with C. rodentium.
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28
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Identification of Antibiotics That Diminish Disease in a Murine Model of Enterohemorrhagic Escherichia coli Infection. Antimicrob Agents Chemother 2020; 64:AAC.02159-19. [PMID: 32015030 DOI: 10.1128/aac.02159-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Accepted: 01/27/2020] [Indexed: 11/20/2022] Open
Abstract
Infections with enterohemorrhagic Escherichia coli (EHEC) cause disease ranging from mild diarrhea to hemolytic-uremic syndrome (HUS) and are the most common cause of renal failure in children in high-income countries. The severity of the disease derives from the release of Shiga toxins (Stx). The use of antibiotics to treat EHEC infections is generally avoided, as it can result in increased stx expression. Here, we systematically tested different classes of antibiotics and found that their influence on stx expression and release varies significantly. We assessed a selection of these antibiotics in vivo using the Citrobacter rodentium ϕstx 2dact mouse model and show that stx 2d-inducing antibiotics resulted in weight loss and kidney damage despite clearance of the infection. However, several non-Stx-inducing antibiotics cleared bacterial infection without causing Stx-mediated pathology. Our results suggest that these antibiotics might be useful in the treatment of EHEC-infected human patients and decrease the risk of HUS development.
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29
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Abstract
The kidney harbours different types of endothelia, each with specific structural and functional characteristics. The glomerular endothelium, which is highly fenestrated and covered by a rich glycocalyx, participates in the sieving properties of the glomerular filtration barrier and in the maintenance of podocyte structure. The microvascular endothelium in peritubular capillaries, which is also fenestrated, transports reabsorbed components and participates in epithelial cell function. The endothelium of large and small vessels supports the renal vasculature. These renal endothelia are protected by regulators of thrombosis, inflammation and complement, but endothelial injury (for example, induced by toxins, antibodies, immune cells or inflammatory cytokines) or defects in factors that provide endothelial protection (for example, regulators of complement or angiogenesis) can lead to acute or chronic renal injury. Moreover, renal endothelial cells can transition towards a mesenchymal phenotype, favouring renal fibrosis and the development of chronic kidney disease. Thus, the renal endothelium is both a target and a driver of kidney and systemic cardiovascular complications. Emerging therapeutic strategies that target the renal endothelium may lead to improved outcomes for both rare and common renal diseases.
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30
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Citrobacter rodentium-host-microbiota interactions: immunity, bioenergetics and metabolism. Nat Rev Microbiol 2019; 17:701-715. [PMID: 31541196 DOI: 10.1038/s41579-019-0252-z] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2019] [Indexed: 12/26/2022]
Abstract
Citrobacter rodentium is an extracellular enteric mouse-specific pathogen used to model infections with human pathogenic Escherichia coli and inflammatory bowel disease. C. rodentium injects type III secretion system effectors into intestinal epithelial cells (IECs) to target inflammatory, metabolic and cell survival pathways and establish infection. While the host responds to infection by activating innate and adaptive immune signalling, required for clearance, the IECs respond by rapidly shifting bioenergetics to aerobic glycolysis, which leads to oxygenation of the epithelium, an instant expansion of mucosal-associated commensal Enterobacteriaceae and a decline of obligate anaerobes. Moreover, infected IECs reprogramme intracellular metabolic pathways, characterized by simultaneous activation of cholesterol biogenesis, import and efflux, leading to increased serum and faecal cholesterol levels. In this Review we summarize recent advances highlighting the intimate relationship between C. rodentium pathogenesis, metabolism and the gut microbiota.
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31
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Reply to Wood and Lee, “Precedence for the Role of Indole with Pathogens”. mBio 2019; 10:mBio.01787-19. [PMID: 31363037 PMCID: PMC6667627 DOI: 10.1128/mbio.01787-19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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32
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Abstract
Microbial establishment within the gastrointestinal (GI) tract requires surveillance of the gut biogeography. The gut microbiota coordinates behaviors by sensing host- or microbiota-derived signals. Here we show for the first time that microbiota-derived indole is highly prevalent in the lumen compared to the intestinal tissue. This difference in indole concentration plays a key role in modulating virulence gene expression of the enteric pathogens enterohemorrhagic Escherichia coli (EHEC) and Citrobacter rodentium Indole decreases expression of genes within the locus of enterocyte effacement (LEE) pathogenicity island, which is essential for these pathogens to form attaching and effacing (AE) lesions on enterocytes. We synthetically altered the concentration of indole in the GI tracts of mice by employing mice treated with antibiotics to deplete the microbiota and reconstituted with indole-producing commensal Bacteroides thetaiotaomicron (B. theta) or a B. theta ΔtnaA mutant (does not produce indole) or by engineering an indole-producing C. rodentium strain. This allowed us to assess the role of self-produced versus microbiota-produced indole, and the results show that decreased indole concentrations promote bacterial pathogenesis, while increased levels of indole decrease bacterial virulence gene expression. Moreover, we identified the bacterial membrane-bound histidine sensor kinase (HK) CpxA as an indole sensor. Enteric pathogens sense a gradient of indole concentrations in the gut to probe different niches and successfully establish an infection.IMPORTANCE Pathogens sense and respond to several small molecules within the GI tract to modulate expression of their virulence repertoire. Indole is a signaling molecule produced by the gut microbiota. Here we show that indole concentrations are higher in the lumen, where the microbiota is present, than in the intestinal tissue. The enteric pathogens EHEC and C. rodentium sense indole to downregulate expression of their virulence genes, as a read-out of the luminal compartment. We also identified the bacterial membrane-bound HK CpxA as an indole sensor. This regulation ensures that EHEC and C. rodentium express their virulence genes only at the epithelial lining, which is the niche they colonize.
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33
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Jourde-Chiche N, Fakhouri F, Dou L, Bellien J, Burtey S, Frimat M, Jarrot PA, Kaplanski G, Le Quintrec M, Pernin V, Rigothier C, Sallée M, Fremeaux-Bacchi V, Guerrot D, Roumenina LT. Endothelium structure and function in kidney health and disease. Nat Rev Nephrol 2019. [PMID: 30607032 DOI: 10.1038/s4158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Abstract
The kidney harbours different types of endothelia, each with specific structural and functional characteristics. The glomerular endothelium, which is highly fenestrated and covered by a rich glycocalyx, participates in the sieving properties of the glomerular filtration barrier and in the maintenance of podocyte structure. The microvascular endothelium in peritubular capillaries, which is also fenestrated, transports reabsorbed components and participates in epithelial cell function. The endothelium of large and small vessels supports the renal vasculature. These renal endothelia are protected by regulators of thrombosis, inflammation and complement, but endothelial injury (for example, induced by toxins, antibodies, immune cells or inflammatory cytokines) or defects in factors that provide endothelial protection (for example, regulators of complement or angiogenesis) can lead to acute or chronic renal injury. Moreover, renal endothelial cells can transition towards a mesenchymal phenotype, favouring renal fibrosis and the development of chronic kidney disease. Thus, the renal endothelium is both a target and a driver of kidney and systemic cardiovascular complications. Emerging therapeutic strategies that target the renal endothelium may lead to improved outcomes for both rare and common renal diseases.
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Affiliation(s)
- Noemie Jourde-Chiche
- Aix-Marseille University, Centre de Nephrologie et Transplantation Renale, AP-HM Hopital de la Conception, Marseille, France.
- Aix-Marseille University, C2VN, INSERM 1263, Institut National de la Recherche Agronomique (INRA) 1260, Faculte de Pharmacie, Marseille, France.
| | - Fadi Fakhouri
- Centre de Recherche en Transplantation et Immunologie, INSERM, Université de Nantes and Department of Nephrology, Centre Hospitalier Universitaire de Nantes, Nantes, France
| | - Laetitia Dou
- Aix-Marseille University, C2VN, INSERM 1263, Institut National de la Recherche Agronomique (INRA) 1260, Faculte de Pharmacie, Marseille, France
| | - Jeremy Bellien
- Department of Pharmacology, Rouen University Hospital and INSERM, Normandy University, Université de Rouen Normandie, Rouen, France
| | - Stéphane Burtey
- Aix-Marseille University, Centre de Nephrologie et Transplantation Renale, AP-HM Hopital de la Conception, Marseille, France
- Aix-Marseille University, C2VN, INSERM 1263, Institut National de la Recherche Agronomique (INRA) 1260, Faculte de Pharmacie, Marseille, France
| | - Marie Frimat
- Université de Lille, INSERM, Centre Hospitalier Universitaire de Lille, U995, Lille Inflammation Research International Center (LIRIC), Lille, France
- Nephrology Department, Centre Hospitalier Universitaire de Lille, Lille, France
| | - Pierre-André Jarrot
- Aix-Marseille University, C2VN, INSERM 1263, Institut National de la Recherche Agronomique (INRA) 1260, Faculte de Pharmacie, Marseille, France
- Assistance Publique-Hôpitaux de Marseille, Service de Médecine Interne et d'Immunologie Clinique, Hôpital de La Conception, Marseille, France
| | - Gilles Kaplanski
- Aix-Marseille University, C2VN, INSERM 1263, Institut National de la Recherche Agronomique (INRA) 1260, Faculte de Pharmacie, Marseille, France
- Assistance Publique-Hôpitaux de Marseille, Service de Médecine Interne et d'Immunologie Clinique, Hôpital de La Conception, Marseille, France
| | - Moglie Le Quintrec
- Centre Hospitalier Universitaire de Lapeyronie, Département de Néphrologie Dialyse et Transplantation Rénale, Montpellier, France
- Institute for Regenerative Medicine and Biotherapy (IRMB), Montpellier, France
| | - Vincent Pernin
- Centre Hospitalier Universitaire de Lapeyronie, Département de Néphrologie Dialyse et Transplantation Rénale, Montpellier, France
- Institute for Regenerative Medicine and Biotherapy (IRMB), Montpellier, France
| | - Claire Rigothier
- Tissue Bioengineering, Université de Bordeaux, Bordeaux, France
- Service de Néphrologie Transplantation, Dialyse et Aphérèse, Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France
| | - Marion Sallée
- Aix-Marseille University, Centre de Nephrologie et Transplantation Renale, AP-HM Hopital de la Conception, Marseille, France
- Aix-Marseille University, C2VN, INSERM 1263, Institut National de la Recherche Agronomique (INRA) 1260, Faculte de Pharmacie, Marseille, France
| | - Veronique Fremeaux-Bacchi
- Assistance Publique-Hôpitaux de Paris, Service d'Immunologie Biologique, Hôpital Européen Georges Pompidou, Paris, France
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
| | - Dominique Guerrot
- Normandie Université, Université de Rouen Normandie, Rouen University Hospital, Department of Nephrology, Rouen, France
| | - Lubka T Roumenina
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France.
- Sorbonne Universités, Paris, France.
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
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Balasubramanian S, Osburne MS, BrinJones H, Tai AK, Leong JM. Prophage induction, but not production of phage particles, is required for lethal disease in a microbiome-replete murine model of enterohemorrhagic E. coli infection. PLoS Pathog 2019; 15:e1007494. [PMID: 30629725 PMCID: PMC6328086 DOI: 10.1371/journal.ppat.1007494] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 12/01/2018] [Indexed: 12/12/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) colonize intestinal epithelium by generating characteristic attaching and effacing (AE) lesions. They are lysogenized by prophage that encode Shiga toxin 2 (Stx2), which is responsible for severe clinical manifestations. As a lysogen, prophage genes leading to lytic growth and stx2 expression are repressed, whereas induction of the bacterial SOS response in response to DNA damage leads to lytic phage growth and Stx2 production both in vitro and in germ-free or streptomycin-treated mice. Some commensal bacteria diminish prophage induction and concomitant Stx2 production in vitro, whereas it has been proposed that phage-susceptible commensals may amplify Stx2 production by facilitating successive cycles of infection in vivo. We tested the role of phage induction in both Stx production and lethal disease in microbiome-replete mice, using our mouse model encompassing the murine pathogen Citrobacter rodentium lysogenized with the Stx2-encoding phage Φstx2dact. This strain generates EHEC-like AE lesions on the murine intestine and causes lethal Stx-mediated disease. We found that lethal mouse infection did not require that Φstx2dact infect or lysogenize commensal bacteria. In addition, we detected circularized phage genomes, potentially in the early stage of replication, in feces of infected mice, confirming that prophage induction occurs during infection of microbiota-replete mice. Further, C. rodentium (Φstx2dact) mutants that do not respond to DNA damage or express stx produced neither high levels of Stx2 in vitro or lethal infection in vivo, confirming that SOS induction and concomitant expression of phage-encoded stx genes are required for disease. In contrast, C. rodentium (Φstx2dact) mutants incapable of prophage genome excision or of packaging phage genomes retained the ability to produce Stx in vitro, as well as to cause lethal disease in mice. Thus, in a microbiome-replete EHEC infection model, lytic induction of Stx-encoding prophage is essential for lethal disease, but actual phage production is not.
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Affiliation(s)
- Sowmya Balasubramanian
- Department of Molecular Biology and Microbiology at Tufts University School of Medicine, Boston, MA, United States of America
| | - Marcia S. Osburne
- Department of Molecular Biology and Microbiology at Tufts University School of Medicine, Boston, MA, United States of America
| | - Haley BrinJones
- Department of Molecular Biology and Microbiology at Tufts University School of Medicine, Boston, MA, United States of America
| | - Albert K. Tai
- Department of Immunology at Tufts University School of Medicine, Boston, MA, United States of America
| | - John M. Leong
- Department of Molecular Biology and Microbiology at Tufts University School of Medicine, Boston, MA, United States of America
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35
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Dextran Sulfate Sodium Colitis Facilitates Colonization with Shiga Toxin-Producing Escherichia coli: a Novel Murine Model for the Study of Shiga Toxicosis. Infect Immun 2018; 86:IAI.00530-18. [PMID: 30150257 DOI: 10.1128/iai.00530-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 08/23/2018] [Indexed: 12/23/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) bacteria are globally important gastrointestinal pathogens causing hemorrhagic gastroenteritis with variable progression to potentially fatal Shiga toxicosis. Little is known about the potential effects of E. coli-derived Shiga-like toxins (STXs) on host gastrointestinal immune responses during infection, in part due to the lack of a reproducible immunocompetent-animal model of STEC infection without depleting the commensal microbiota. Here, we describe a novel and reproducible murine model utilizing dextran sulfate sodium (DSS) colitis to induce susceptibility to colonization with clinical-isolate STEC strains. After exposure to DSS and subsequent oral STEC challenge, all the mice were colonized, and 66% of STEC-infected mice required early euthanasia. Morbidity during STEC infection, but not infection with an isogenic STEC mutant with toxin deleted, was associated with increased renal transcripts of the injury markers KIM1 and NGAL, histological evidence of renal tubular injury, and increased renal interleukin 6 gene (IL-6) and CXCL1 inflammatory transcripts. Interestingly, the intestinal burden of STEC during infection was increased compared to its isogenic Shiga toxin deletion strain. Increased bacterial burdens during Shiga toxin production coincided with decreased induction of colonic IL-23 axis transcripts known to be critical for clearance of similar gastrointestinal pathogens in mice, suggesting a previously undescribed role for STEC Shiga toxins in suppressing host immune responses during STEC infection and survival. The DSS+STEC model establishes infection with clinical-isolate strains of STEC in immunocompetent mice without depleting the gastrointestinal microbiota, enabling characterization of the effects of STXs on the IL-23 axis and other gastrointestinal pathogen-host interactions.
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36
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Redox, amino acid, and fatty acid metabolism intersect with bacterial virulence in the gut. Proc Natl Acad Sci U S A 2018; 115:E10712-E10719. [PMID: 30348782 DOI: 10.1073/pnas.1813451115] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The gut metabolic landscape is complex and is influenced by the microbiota, host physiology, and enteric pathogens. Pathogens have to exquisitely monitor the biogeography of the gastrointestinal tract to find a suitable niche for colonization. To dissect the important metabolic pathways that influence virulence of enterohemorrhagic Escherichia coli (EHEC), we conducted a high-throughput screen. We generated a dataset of regulatory pathways that control EHEC virulence expression under anaerobic conditions. This unraveled that the cysteine-responsive regulator, CutR, converges with the YhaO serine import pump and the fatty acid metabolism regulator FadR to optimally control virulence expression in EHEC. CutR activates expression of YhaO to increase activity of the YhaJ transcription factor that has been previously shown to directly activate the EHEC virulence genes. CutR enhances FadL, which is a pump for fatty acids that represses inhibition of virulence expression by FadR, unmasking a feedback mechanism responsive to metabolite fluctuations. Moreover, CutR and FadR also augment murine infection by Citrobacter rodentium, which is a murine pathogen extensively employed as a surrogate animal model for EHEC. This high-throughput approach proved to be a powerful tool to map the web of cellular circuits that allows an enteric pathogen to monitor the gut environment and adjust the levels of expression of its virulence repertoire toward successful infection of the host.
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37
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Hernandez-Doria JD, Sperandio V. Bacteriophage Transcription Factor Cro Regulates Virulence Gene Expression in Enterohemorrhagic Escherichia coli. Cell Host Microbe 2018; 23:607-617.e6. [PMID: 29746832 DOI: 10.1016/j.chom.2018.04.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/15/2018] [Accepted: 04/16/2018] [Indexed: 10/16/2022]
Abstract
Bacteriophage-encoded genetic elements control bacterial biological functions. Enterohemorrhagic Escherichia coli (EHEC) strains harbor lambda-phages encoding the Shiga-toxin (Stx), which is expressed during the phage lytic cycle and associated with exacerbated disease. Phages also reside dormant within bacterial chromosomes through their lysogenic cycle, but how this impacts EHEC virulence remains unknown. We find that during lysogeny the phage transcription factor Cro activates the EHEC type III secretion system (T3SS). EHEC lambdoid phages are lysogenic under anaerobic conditions when Cro binds to and activates the promoters of T3SS genes. Interestingly, the Cro sequence varies among phages carried by different EHEC outbreak strains, and these changes affect Cro-dependent T3SS regulation. Additionally, infecting mice with the related pathogen C. rodentium harboring the bacteriophage cro from EHEC results in greater T3SS gene expression and enhanced virulence. Collectively, these findings reveal the role of phages in impacting EHEC virulence and their potential to affect outbreak strains.
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Affiliation(s)
- Juan D Hernandez-Doria
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9048, USA; Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390-9048, USA
| | - Vanessa Sperandio
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9048, USA; Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390-9048, USA.
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38
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Nicolay JP, Thorn V, Daniel C, Amann K, Siraskar B, Lang F, Hillgruber C, Goerge T, Hoffmann S, Gorzelanny C, Huck V, Mess C, Obser T, Schneppenheim R, Fleming I, Schneider MF, Schneider SW. Cellular stress induces erythrocyte assembly on intravascular von Willebrand factor strings and promotes microangiopathy. Sci Rep 2018; 8:10945. [PMID: 30026593 PMCID: PMC6053440 DOI: 10.1038/s41598-018-28961-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 07/01/2018] [Indexed: 11/17/2022] Open
Abstract
Microangiopathy with subsequent organ damage represents a major complication in several diseases. The mechanisms leading to microvascular occlusion include von Willebrand factor (VWF), notably the formation of ultra-large von Willebrand factor fibers (ULVWFs) and platelet aggregation. To date, the contribution of erythrocytes to vascular occlusion is incompletely clarified. We investigated the platelet-independent interaction between stressed erythrocytes and ULVWFs and its consequences for microcirculation and organ function under dynamic conditions. In response to shear stress, erythrocytes interacted strongly with VWF to initiate the formation of ULVWF/erythrocyte aggregates via the binding of Annexin V to the VWF A1 domain. VWF-erythrocyte adhesion was attenuated by heparin and the VWF-specific protease ADAMTS13. In an in vivo model of renal ischemia/reperfusion injury, erythrocytes adhered to capillaries of wild-type but not VWF-deficient mice and later resulted in less renal damage. In vivo imaging in mice confirmed the adhesion of stressed erythrocytes to the vessel wall. Moreover, enhanced eryptosis rates and increased VWF binding were detected in blood samples from patients with chronic renal failure. Our study demonstrates that stressed erythrocytes have a pronounced binding affinity to ULVWFs. The discovered mechanisms suggest that erythrocytes are essential for the pathogenesis of microangiopathies and renal damage by actively binding to ULVWFs.
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Affiliation(s)
- Jan P Nicolay
- Department of Dermatology, Venereology and Allergy, University Medical Center Mannheim, Ruprecht-Karls-University of Heidelberg, Mannheim, Germany. .,Division of Immunogenetics, German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Verena Thorn
- Department of Dermatology, Venereology and Allergy, University Medical Center Mannheim, Ruprecht-Karls-University of Heidelberg, Mannheim, Germany
| | - Christoph Daniel
- Department of Nephropathology, Friedrich-Alexander-University (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Kerstin Amann
- Department of Nephropathology, Friedrich-Alexander-University (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | | | - Florian Lang
- Department of Physiology, University of Tübingen, Tübingen, Germany
| | - Carina Hillgruber
- Department of Dermatology, University Hospital Münster, Münster, Germany
| | - Tobias Goerge
- Department of Dermatology, University Hospital Münster, Münster, Germany
| | - Stefan Hoffmann
- Institute of Plant Biology and Biotechnology (IBBP), Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Christian Gorzelanny
- Department of Dermatology, Venereology and Allergy, University Medical Center Mannheim, Ruprecht-Karls-University of Heidelberg, Mannheim, Germany.,Department of Dermatology and Venerology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Volker Huck
- Department of Dermatology, Venereology and Allergy, University Medical Center Mannheim, Ruprecht-Karls-University of Heidelberg, Mannheim, Germany.,Department of Dermatology and Venerology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian Mess
- Department of Dermatology and Venerology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tobias Obser
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Reinhard Schneppenheim
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ingrid Fleming
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, Frankfurt am Main, Germany
| | | | - Stefan W Schneider
- Department of Dermatology and Venerology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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39
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Kang E, Crouse A, Chevallier L, Pontier SM, Alzahrani A, Silué N, Campbell-Valois FX, Montagutelli X, Gruenheid S, Malo D. Enterobacteria and host resistance to infection. Mamm Genome 2018; 29:558-576. [PMID: 29785663 DOI: 10.1007/s00335-018-9749-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 05/14/2018] [Indexed: 02/06/2023]
Abstract
Enterobacteriaceae are a large family of Gram-negative, non-spore-forming bacteria. Although many species exist as part of the natural flora of animals including humans, some members are associated with both intestinal and extraintestinal diseases. In this review, we focus on members of this family that have important roles in human disease: Salmonella, Escherichia, Shigella, and Yersinia, providing a brief overview of the disease caused by these bacteria, highlighting the contribution of animal models to our understanding of their pathogenesis and of host genetic determinants involved in susceptibility or resistance to infection.
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Affiliation(s)
- Eugene Kang
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
- McGill Research Center on Complex Traits, McGill University, Montreal, QC, Canada
| | - Alanna Crouse
- McGill Research Center on Complex Traits, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Lucie Chevallier
- U955 - IMRB, Team 10 - Biology of the neuromuscular system, Inserm, École Nationale Vétérinaire d'Alfort, UPEC, Maisons-Alfort, France
- Mouse Genetics Laboratory, Department of Genomes and Genetics, Institut Pasteur, Paris, France
| | - Stéphanie M Pontier
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, University of Ottawa, Ottawa, ON, Canada
| | - Ashwag Alzahrani
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, University of Ottawa, Ottawa, ON, Canada
| | - Navoun Silué
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, University of Ottawa, Ottawa, ON, Canada
| | - François-Xavier Campbell-Valois
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, University of Ottawa, Ottawa, ON, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Xavier Montagutelli
- U955 - IMRB, Team 10 - Biology of the neuromuscular system, Inserm, École Nationale Vétérinaire d'Alfort, UPEC, Maisons-Alfort, France
| | - Samantha Gruenheid
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
- McGill Research Center on Complex Traits, McGill University, Montreal, QC, Canada
| | - Danielle Malo
- McGill Research Center on Complex Traits, McGill University, Montreal, QC, Canada.
- Department of Human Genetics, McGill University, Montreal, QC, Canada.
- Department of Medicine, McGill University, Montreal, QC, Canada.
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40
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Kuo CJ, Wang ST, Chen CS. Detection of Enterohemorrhagic Escherichia Coli Colonization in Murine Host by Non-invasive In Vivo Bioluminescence System. J Vis Exp 2018. [PMID: 29683443 DOI: 10.3791/56169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Enterohemorrhagic E. coli (EHEC) O157:H7, which is a foodborne pathogen that causesdiarrhea, hemorrhagic colitis (HS), and hemolytic uremic syndrome (HUS), colonize to the intestinal tract of humans. To study the detailed mechanism of EHEC colonization in vivo, it is essential to have animal models to monitor and quantify EHEC colonization. We demonstrate here a mouse-EHEC colonization model by transforming the bioluminescent expressing plasmid to EHEC to monitor and quantify EHEC colonization in living hosts. Animals inoculated with bioluminescence-labeled EHEC show intense bioluminescent signals in mice by detection with a non-invasive in vivo imaging system. After 1 and 2 days post infection, bioluminescent signals could still be detected in infected animals, which suggests that EHEC colonize in hosts for at least 2 days. We also demonstrate that these bioluminescent EHEC locate to mouse intestine, specifically in the cecum and colon, from ex vivo images. This mouse-EHEC colonization model may serve as a tool to advance the current knowledge of the EHEC colonization mechanism.
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Affiliation(s)
- Cheng-Ju Kuo
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University; Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University
| | - Sin-Tian Wang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University; Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University
| | - Chang-Shi Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University; Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University;
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41
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The QseG Lipoprotein Impacts the Virulence of Enterohemorrhagic Escherichia coli and Citrobacter rodentium and Regulates Flagellar Phase Variation in Salmonella enterica Serovar Typhimurium. Infect Immun 2018; 86:IAI.00936-17. [PMID: 29358334 DOI: 10.1128/iai.00936-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 01/12/2018] [Indexed: 11/20/2022] Open
Abstract
The QseEF histidine kinase/response regulator system modulates expression of enterohemorrhagic Escherichia coli (EHEC) and Salmonella enterica serovar Typhimurium virulence genes in response to the host neurotransmitters epinephrine and norepinephrine. qseG, which encodes an outer membrane lipoprotein, is cotranscribed with qseEF in these enteric pathogens, but there is little knowledge of its role in virulence. Here, we found that in EHEC QseG interacts with the type III secretion system (T3SS) gate protein SepL and modulates the kinetics of attaching and effacing (AE) lesion formation on tissue-cultured cells. Moreover, an EHEC ΔqseG mutant had reduced intestinal colonization in an infant rabbit model. Additionally, in Citrobacter rodentium, an AE lesion-forming pathogen like EHEC, QseG is required for full virulence in a mouse model. In S Typhimurium, we found that QseG regulates the phase switch between the two flagellin types, FliC and FljB. In an S Typhimurium ΔqseG mutant, the phase-variable promoter for fljB is preferentially switched into the "on" position, leading to overproduction of this phase two flagellin. In infection of tissue-cultured cells, the S Typhimurium ΔqseG mutant provokes increased inflammatory cytokine production versus the wild type; in vivo, in a murine infection model, the ΔqseG strain caused a more severe inflammatory response and was attenuated versus the wild-type strain. Collectively, our findings demonstrate that QseG is important for full virulence in several enteric pathogens and controls flagellar phase variation in S Typhimurium, and they highlight both the complexity and conservation of the regulatory networks that control the virulence of enteric pathogens.
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42
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Bowen EE, Coward RJ. Advances in our understanding of the pathogenesis of hemolytic uremic syndromes. Am J Physiol Renal Physiol 2017; 314:F454-F461. [PMID: 29167171 DOI: 10.1152/ajprenal.00376.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Hemolytic uremic syndrome (HUS) is major global health care issue as it is the leading cause of acute kidney injury in children. It is a triad of acute kidney injury, microangiopathic hemolytic anemia, and thrombocytopenia. In recent years, major advances in our understanding of complement-driven inherited rare forms of HUS have been achieved. However, in children 90% of cases of HUS are associated with a Shiga toxin-producing enteric pathogen. The precise pathological mechanisms in this setting are yet to be elucidated. The purpose of this review is to discuss advances in our understanding of the pathophysiology underlying HUS and identify the key questions yet to be answered by the scientific community.
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Affiliation(s)
- E E Bowen
- Academic Renal Unit, School of Clinical Sciences, University of Bristol , Bristol , United Kingdom
| | - R J Coward
- Academic Renal Unit, School of Clinical Sciences, University of Bristol , Bristol , United Kingdom
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43
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Bouladoux N, Harrison OJ, Belkaid Y. The Mouse Model of Infection with Citrobacter rodentium. ACTA ACUST UNITED AC 2017; 119:19.15.1-19.15.25. [PMID: 29091261 DOI: 10.1002/cpim.34] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Citrobacter rodentium is a murine mucosal pathogen used as a model to elucidate the molecular and cellular pathogenesis of infection with two clinically important human gastrointestinal pathogens, enteropathogenic Escherichia coli (EPEC) and enterohaemorrhagic E. coli (EHEC). C. rodentium infection provides an excellent model to study different aspects of host-pathogen interaction in the gut, including intestinal inflammatory responses during bacteria-induced colitis, mucosal healing and epithelial repair, the induction of mucosal immune responses, and the role of the intestinal microbiota in mediating resistance to colonization by enteric pathogens. This unit provides detailed protocols for growing this bacterium, infecting mice by intragastric inoculation, measuring bacterial loads in feces and organs, and monitoring intestinal pathology induced by infection. Additional protocols describe steps needed to create frozen stocks, establish a growth curve, perform ex vivo organ cultures, isolate immune cells from the large intestine, and measure immune response by flow cytometry. © 2017 by John Wiley & Sons, Inc.
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Affiliation(s)
- Nicolas Bouladoux
- Mucosal Immunology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland.,NIAID Microbiome Program, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland
| | - Oliver J Harrison
- Mucosal Immunology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland
| | - Yasmine Belkaid
- Mucosal Immunology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland.,NIAID Microbiome Program, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland
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Citrobacter rodentium: a model enteropathogen for understanding the interplay of innate and adaptive components of type 3 immunity. Mucosal Immunol 2017; 10:1108-1117. [PMID: 28612839 PMCID: PMC5969517 DOI: 10.1038/mi.2017.47] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 04/13/2017] [Indexed: 02/07/2023]
Abstract
Citrobacter rodentium is a natural murine intestinal pathogen that shares a core set of virulence factors with the related human pathogens enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC). C. rodentium is now the most widely used small animal model for studying the molecular underpinnings of EPEC and EHEC infections in vivo, including: enterocyte attachment; virulence; colonization resistance; and mucosal immunity. In this review, we discuss type 3 immunity in the context of C. rodentium infection and discuss recent publications that use this model to understand how the innate and adaptive components of immunity intersect to mediate host protection against enteric pathogens and maintain homeostasis with the microbiota.
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Abstract
The biogeography of the gut is diverse in its longitudinal axis, as well as within specific microenvironments. Differential oxygenation and nutrient composition drive the membership of microbial communities in these habitats. Moreover, enteric pathogens can orchestrate further modifications to gain a competitive advantage toward host colonization. These pathogens are versatile and adept when exploiting the human colon. They expertly navigate complex environmental cues and interkingdom signaling to colonize and infect their hosts. Here we demonstrate how enterohemorrhagic Escherichia coli (EHEC) uses three sugar-sensing transcription factors, Cra, KdpE, and FusR, to exquisitely regulate the expression of virulence factors associated with its type III secretion system (T3SS) when exposed to various oxygen concentrations. We also explored the effect of mucin-derived nonpreferred carbon sources on EHEC growth and expression of virulence genes. Taken together, the results show that EHEC represses the expression of its T3SS when oxygen is absent, mimicking the largely anaerobic lumen, and activates its T3SS when oxygen is available through Cra. In addition, when EHEC senses mucin-derived sugars heavily present in the O-linked and N-linked glycans of the large intestine, virulence gene expression is initiated. Sugars derived from pectin, a complex plant polysaccharide digested in the large intestine, also increased virulence gene expression. Not only does EHEC sense host- and microbiota-derived interkingdom signals, it also uses oxygen availability and mucin-derived sugars liberated by the microbiota to stimulate expression of the T3SS. This precision in gene regulation allows EHEC to be an efficient pathogen with an extremely low infectious dose. Enteric pathogens have to be crafty when interpreting multiple environmental cues to successfully establish themselves within complex and diverse gut microenvironments. Differences in oxygen tension and nutrient composition determine the biogeography of the gut microbiota and provide unique niches that can be exploited by enteric pathogens. EHEC is an enteric pathogen that colonizes the colon and causes outbreaks of bloody diarrhea and hemolytic-uremic syndrome worldwide. It has a very low infectious dose, which requires it to be an extremely effective pathogen. Hence, here we show that EHEC senses multiple sugar sources and oxygen levels to optimally control the expression of its virulence repertoire. This exquisite regulatory control equips EHEC to sense different intestinal compartments to colonize the host.
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Flowers LJ, Bou Ghanem EN, Leong JM. Synchronous Disease Kinetics in a Murine Model for Enterohemorrhagic E. coli Infection Using Food-Borne Inoculation. Front Cell Infect Microbiol 2016; 6:138. [PMID: 27857935 PMCID: PMC5093121 DOI: 10.3389/fcimb.2016.00138] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 10/07/2016] [Indexed: 11/29/2022] Open
Abstract
Upon colonization of the intestinal epithelium, the attaching and effacing (AE) pathogen Enterohemorrhagic Escherichia coli (EHEC) effaces microvilli and forms pedestal-like structures beneath the adherent bacterium. The production of one of its virulence factors, the phage-encoded Shiga toxin (Stx) results in systemic disease, including the development of renal failure. Although EHEC does not productively infect conventional mice, EHEC infection can be modeled in mice utilizing a derivative of the natural murine AE pathogen Citrobacter rodentium (CR). Gavage of mice with CR(ΦStx2dact), a C. rodentium lysogenized by a phage encoding an Stx variant with high potency in mice, features AE lesion formation on intestinal epithelium and Stx-mediated systemic disease, including renal damage. This model is somewhat limited by mouse-to-mouse variation in the course of disease, with the time to severe morbidity (and required euthanasia) varying by as many as 5 days, a feature that limits pathological analysis at defined stages of disease. In the current study, we altered and optimized the preparation, dose, and mode of delivery of CR(ΦStx2dact), using food-borne route of infection to generate highly synchronous disease model. We found that food-borne inoculation of as few as 3 × 104 CR(ΦStx2dact) resulted in productive colonization and severe systemic disease. Upon inoculation of 1 × 108 bacteria, the majority of infected animals suffered weight loss beginning 5 days post-infection and all required euthanasia on day 6 or 7. This enhanced murine model for EHEC infection should facilitate characterization of the pathology associated with specific phases of Stx-mediated disease.
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Affiliation(s)
- Laurice J Flowers
- Molecular Biology and Microbiology, Sackler School of Graduate Biomedical Sciences, Tufts University Boston, MA, USA
| | - Elsa N Bou Ghanem
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine Boston, MA, USA
| | - John M Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine Boston, MA, USA
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Crepin VF, Collins JW, Habibzay M, Frankel G. Citrobacter rodentium mouse model of bacterial infection. Nat Protoc 2016; 11:1851-76. [PMID: 27606775 DOI: 10.1038/nprot.2016.100] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Infection of mice with Citrobacter rodentium is a robust model to study bacterial pathogenesis, mucosal immunology, the health benefits of probiotics and the role of the microbiota during infection. C. rodentium was first isolated by Barthold from an outbreak of mouse diarrhea in Yale University in 1972 and was 'rediscovered' by Falkow and Schauer in 1993. Since then the use of the model has proliferated, and it is now the gold standard for studying virulence of the closely related human pathogens enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC, respectively). Here we provide a detailed protocol for various applications of the model, including bacterial growth, site-directed mutagenesis, mouse inoculation (from cultured cells and after cohabitation), monitoring of bacterial colonization, tissue extraction and analysis, immune responses, probiotic treatment and microbiota analysis. The main protocol, from mouse infection to clearance and analysis of tissues and host responses, takes ∼5 weeks to complete.
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Affiliation(s)
- Valerie F Crepin
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - James W Collins
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Maryam Habibzay
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Gad Frankel
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, UK
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Vanaja SK, Russo AJ, Behl B, Banerjee I, Yankova M, Deshmukh SD, Rathinam VAK. Bacterial Outer Membrane Vesicles Mediate Cytosolic Localization of LPS and Caspase-11 Activation. Cell 2016; 165:1106-1119. [PMID: 27156449 DOI: 10.1016/j.cell.2016.04.015] [Citation(s) in RCA: 470] [Impact Index Per Article: 58.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 02/12/2016] [Accepted: 04/01/2016] [Indexed: 01/22/2023]
Abstract
Sensing of lipopolysaccharide (LPS) in the cytosol triggers caspase-11 activation and is central to host defense against Gram-negative bacterial infections and to the pathogenesis of sepsis. Most Gram-negative bacteria that activate caspase-11, however, are not cytosolic, and the mechanism by which LPS from these bacteria gains access to caspase-11 in the cytosol remains elusive. Here, we identify outer membrane vesicles (OMVs) produced by Gram-negative bacteria as a vehicle that delivers LPS into the cytosol triggering caspase-11-dependent effector responses in vitro and in vivo. OMVs are internalized via endocytosis, and LPS is released into the cytosol from early endosomes. The use of hypovesiculating bacterial mutants, compromised in their ability to generate OMVs, reveals the importance of OMVs in mediating the cytosolic localization of LPS. Collectively, these findings demonstrate a critical role for OMVs in enabling the cytosolic entry of LPS and, consequently, caspase-11 activation during Gram-negative bacterial infections.
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Affiliation(s)
- Sivapriya Kailasan Vanaja
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Avenue, Farmington, CT 06030, USA
| | - Ashley J Russo
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Avenue, Farmington, CT 06030, USA
| | - Bharat Behl
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Avenue, Farmington, CT 06030, USA
| | - Ishita Banerjee
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Avenue, Farmington, CT 06030, USA
| | - Maya Yankova
- Central Electron Microscopy Facility, UConn Health School of Medicine, 263 Farmington Avenue, Farmington, CT 06030, USA
| | - Sachin D Deshmukh
- Center for Sepsis Control and Care, Jena University Hospital, Erlanger Allee 101, 07747 Jena, Germany
| | - Vijay A K Rathinam
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Avenue, Farmington, CT 06030, USA.
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Biological Activities of Uric Acid in Infection Due to Enteropathogenic and Shiga-Toxigenic Escherichia coli. Infect Immun 2016; 84:976-988. [PMID: 26787720 DOI: 10.1128/iai.01389-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 01/14/2016] [Indexed: 01/26/2023] Open
Abstract
In previous work, we identified xanthine oxidase (XO) as an important enzyme in the interaction between the host and enteropathogenic Escherichia coli(EPEC) and Shiga-toxigenic E. coli(STEC). Many of the biological effects of XO were due to the hydrogen peroxide produced by the enzyme. We wondered, however, if uric acid generated by XO also had biological effects in the gastrointestinal tract. Uric acid triggered inflammatory responses in the gut, including increased submucosal edema and release of extracellular DNA from host cells. While uric acid alone was unable to trigger a chloride secretory response in intestinal monolayers, it did potentiate the secretory response to cyclic AMP agonists. Uric acid crystals were formed in vivo in the lumen of the gut in response to EPEC and STEC infections. While trying to visualize uric acid crystals formed during EPEC and STEC infections, we noticed that uric acid crystals became enmeshed in the neutrophilic extracellular traps (NETs) produced from host cells in response to bacteria in cultured cell systems and in the intestine in vivo Uric acid levels in the gut lumen increased in response to exogenous DNA, and these increases were enhanced by the actions of DNase I. Interestingly, addition of DNase I reduced the numbers of EPEC bacteria recovered after a 20-h infection and protected against EPEC-induced histologic damage.
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Abstract
The first major outbreaks caused by enterohemorrhagic Escherichia coli (EHEC) raised public and medical awareness of the risks associated with acquiring this potentially deadly infection. The widespread presence of these organisms in the environment, the severity of the clinical sequelae, and the lack of treatment options and effective preventive measures demand that we obtain a better understanding of how this group of organisms cause disease. Animal models allow study of the processes and factors that contribute to disease and, as such, form a valuable tool in the repertoire of infectious disease researchers. Yet despite more than 30 years of research, it seems that no single model host reproduces the full spectrum of clinical disease induced by EHEC in humans. In the first part of this review, a synopsis of what is known about EHEC infections is garnered from human outbreaks and biopsy specimens. The main features and limitations of EHEC infection models that are based on the three most commonly used species (pigs, rabbits, and mice) are described within a historical context. Recent advances are highlighted, and a brief overview of models based on other species is given. Finally, the impact of the host on moderating EHEC infection is considered in light of growing evidence for the need to consider the biology and virulence strategies of EHEC in the context of its niche within the intestine.
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