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Zangara MT, Darwish L, Coombes BK. Characterizing the Pathogenic Potential of Crohn's Disease-Associated Adherent-Invasive Escherichia coli. EcoSal Plus 2023; 11:eesp00182022. [PMID: 37220071 PMCID: PMC10729932 DOI: 10.1128/ecosalplus.esp-0018-2022] [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: 03/20/2023] [Accepted: 05/04/2023] [Indexed: 01/28/2024]
Abstract
The microbiome of Crohn's disease (CD) patients is composed of a microbial community that is considered dysbiotic and proinflammatory in nature. The overrepresentation of Enterobacteriaceae species is a common feature of the CD microbiome, and much attention has been given to understanding the pathogenic role this feature plays in disease activity. Over 2 decades ago, a new Escherichia coli subtype called adherent-invasive E. coli (AIEC) was isolated and linked to ileal Crohn's disease. Since the isolation of the first AIEC strain, additional AIEC strains have been isolated from both inflammatory bowel disease (IBD) patients and non-IBD individuals using the original in vitro phenotypic characterization methods. Identification of a definitive molecular marker of the AIEC pathotype has been elusive; however, significant advancements have been made in understanding the genetic, metabolic, and virulence determinants of AIEC infection biology. Here, we review the current knowledge of AIEC pathogenesis to provide additional, objective measures that could be considered in defining AIEC and their pathogenic potential.
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Affiliation(s)
- Megan T. Zangara
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Lena Darwish
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Brian K. Coombes
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, Hamilton, Ontario, Canada
- Farncombe Family Digestive Health Research Institute, Hamilton, Ontario, Canada
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2
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Qu D, Yu L, Tian F, Zhang H, Chen W, Gu Z, Zhai Q. Bifidobacterium bifidum FJSWX19M5 alleviated 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced chronic colitis by mitigating gut barrier injury and increasing regulatory T cells. Food Funct 2023; 14:181-194. [PMID: 36477762 DOI: 10.1039/d2fo02659g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Probiotics have been evaluated as alternative approaches for preventing the relapse of Crohn's disease (CD). Previously, we observed strain-specific anti-inflammatory properties of Bifidobacterium bifidum in 2,4,6-trinitrobenzene sulfonic acid (TNBS) acute colitis models. In this study, we further assessed the effects of several B. bifidum strains on colonic damage, fibrosis, inflammatory factors, intestinal microbial and metabolic profiles, and peripheral regulatory T cells (Tregs) in the context of TNBS chronic colitis in mice. These results indicated that B. bifidum FJSWX19M5, but not FXJWS17M4, ameliorated body weight loss, reduced colonic shortening and injury, decreased markers of gut inflammation, and rebalanced colonic metabolism in TNBS-treated mice. FJSWX19M5 supplementation also promoted Treg cell differentiation and intestinal barrier restoration compared to other strains. All living B. bifidum strains (FJSWX19M5, FXJWS17M4 and FHENJZ3M6) seemed to restore the disruption of the gut microbiota caused by TNBS. The co-culture of B. bifidum strains and mesenteric lymph node cells from TNBS-treated mice showed that those strains with anti-colitis could induce higher IL-10 levels and a lower ratio of IL-22/IL-10 and IL-17/IL-10 when compared to those strains that were not protective. Furthermore, heat-killed FJSWX19M5 exhibited a relief effect on colitis-related symptoms (including body weight loss, colonic shortening and injury). These data imply that specific B. bifidum strains or their lysates may be the current therapeutic alternatives for CD.
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Affiliation(s)
- Dingwu Qu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China. .,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Leilei Yu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China. .,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Fengwei Tian
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China. .,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Hao Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China. .,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.,National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, Jiangsu 214122, China.,Wuxi Translational Medicine Research Center and Jiangsu Translational, Medicine Research Institute, Wuxi Branch, China
| | - Wei Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China. .,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.,National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Zhennan Gu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China. .,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Qixiao Zhai
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China. .,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
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Abstract
The surge in inflammatory bowel diseases, like Crohn's disease (CD), is alarming. While the role of the gut microbiome in CD development is unresolved, the frequent isolation of adherent-invasive Escherichia coli (AIEC) strains from patient biopsies, together with their propensity to trigger gut inflammation, underpin the potential role of these bacteria as disease modifiers. In this review, we explore the spectrum of AIEC pathogenesis, including their metabolic versatility in the gut. We describe how AIEC strains hijack the host defense mechanisms to evade immune attrition and promote inflammation. Furthermore, we highlight the key traits that differentiate AIEC from commensal E. coli. Deciphering the main components of AIEC virulence is cardinal to the discovery of the next generation of antimicrobials that can selectively eradicate CD-associated bacteria.
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Affiliation(s)
- Sarah Mansour
- Department of Medical Microbiology & Immunology, Faculty of Medicine & Dentistry, University of Alberta, Canada
| | - Tahreem Asrar
- Department of Medical Microbiology & Immunology, Faculty of Medicine & Dentistry, University of Alberta, Canada
| | - Wael Elhenawy
- Department of Medical Microbiology & Immunology, Faculty of Medicine & Dentistry, University of Alberta, Canada,Division of Gastroenterology, Department of Medicine, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada,Li Ka Shing Institute of Virology, Canada,Women and Children’s Health Research Institute, Edmonton, Alberta, Canada,Antimicrobial Resistance, One Health Consortium - Edmonton, AB, Canada,CONTACT Wael Elhenawy Department of Medical Microbiology & Immunology, Faculty of Medicine & Dentistry, University of Alberta
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4
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Biofilms and Benign Colonic Diseases. Int J Mol Sci 2022; 23:ijms232214259. [PMID: 36430737 PMCID: PMC9698058 DOI: 10.3390/ijms232214259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/06/2022] [Accepted: 11/10/2022] [Indexed: 11/19/2022] Open
Abstract
The colon has a very large surface area that is covered by a dense mucus layer. The biomass in the colon includes 500-1000 bacterial species at concentrations of ~1012 colony-forming units per gram of feces. The intestinal epithelial cells and the commensal bacteria in the colon have a symbiotic relationship that results in nutritional support for the epithelial cells by the bacteria and maintenance of the optimal commensal bacterial population by colonic host defenses. Bacteria can form biofilms in the colon, but the exact frequency is uncertain because routine methods to undertake colonoscopy (i.e., bowel preparation) may dislodge these biofilms. Bacteria in biofilms represent a complex community that includes living and dead bacteria and an extracellular matrix composed of polysaccharides, proteins, DNA, and exogenous debris in the colon. The formation of biofilms occurs in benign colonic diseases, such as inflammatory bowel disease and irritable bowel syndrome. The development of a biofilm might serve as a marker for ongoing colonic inflammation. Alternatively, the development of biofilms could contribute to the pathogenesis of these disorders by providing sanctuaries for pathogenic bacteria and reducing the commensal bacterial population. Therapeutic approaches to patients with benign colonic diseases could include the elimination of biofilms and restoration of normal commensal bacteria populations. However, these studies will be extremely difficult unless investigators can develop noninvasive methods for measuring and identifying biofilms. These methods that might include the measurement of quorum sensing molecules, measurement of bile acids, and identification of bacteria uniquely associated with biofilms in the colon.
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Gerner RR, Hossain S, Sargun A, Siada K, Norton GJ, Zheng T, Neumann W, Nuccio SP, Nolan EM, Raffatellu M. Siderophore Immunization Restricted Colonization of Adherent-Invasive Escherichia coli and Ameliorated Experimental Colitis. mBio 2022; 13:e0218422. [PMID: 36094114 PMCID: PMC9600343 DOI: 10.1128/mbio.02184-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 08/03/2022] [Indexed: 11/20/2022] Open
Abstract
Inflammatory bowel diseases (IBD) are characterized by chronic inflammation of the gastrointestinal tract and profound alterations to the gut microbiome. Adherent-invasive Escherichia coli (AIEC) is a mucosa-associated pathobiont that colonizes the gut of patients with Crohn's disease, a form of IBD. Because AIEC exacerbates gut inflammation, strategies to reduce the AIEC bloom during colitis are highly desirable. To thrive in the inflamed gut, Enterobacteriaceae acquire the essential metal nutrient iron by producing and releasing siderophores. Here, we implemented an immunization-based strategy to target the siderophores enterobactin and its glucosylated derivative salmochelin to reduce the AIEC bloom in the inflamed gut. Using chemical (dextran sulfate sodium) and genetic (Il10-/- mice) IBD mouse models, we showed that immunization with enterobactin conjugated to the mucosal adjuvant cholera toxin subunit B potently elicited mucosal and serum antibodies against these siderophores. Siderophore-immunized mice exhibited lower AIEC gut colonization, diminished AIEC association with the gut mucosa, and reduced colitis severity. Moreover, Peyer's patches and the colonic lamina propria harbored enterobactin-specific B cells that could be identified by flow cytometry. The beneficial effect of siderophore immunization was primarily B cell-dependent because immunized muMT-/- mice, which lack mature B lymphocytes, were not protected during AIEC infection. Collectively, our study identified siderophores as a potential therapeutic target to reduce AIEC colonization and its association with the gut mucosa, which ultimately may reduce colitis exacerbation. Moreover, this work provides the foundation for developing monoclonal antibodies against siderophores, which could provide a narrow-spectrum strategy to target the AIEC bloom in Crohn's disease patients. IMPORTANCE Adherent-invasive Escherichia coli (AIEC) is abnormally prevalent in patients with ileal Crohn's disease and exacerbates intestinal inflammation, but treatment strategies that selectively target AIEC are unavailable. Iron is an essential micronutrient for most living organisms, and bacterial pathogens have evolved sophisticated strategies to capture iron from the host environment. AIEC produces siderophores, small, secreted molecules with a high affinity for iron. Here, we showed that immunization to elicit antibodies against siderophores promoted a reduction of the AIEC bloom, interfered with AIEC association with the mucosa, and mitigated colitis in experimental mouse models. We also established a flow cytometry-based approach to visualize and isolate siderophore-specific B cells, a prerequisite for engineering monoclonal antibodies against these molecules. Together, this work could lead to a more selective and antibiotic-sparing strategy to target AIEC in Crohn's disease patients.
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Affiliation(s)
- Romana R. Gerner
- Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California San Diego, La Jolla, California, USA
| | - Suzana Hossain
- Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California San Diego, La Jolla, California, USA
| | - Artur Sargun
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Kareem Siada
- Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California San Diego, La Jolla, California, USA
| | - Grant J. Norton
- Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California San Diego, La Jolla, California, USA
| | - Tengfei Zheng
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Wilma Neumann
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Sean-Paul Nuccio
- Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California San Diego, La Jolla, California, USA
| | - Elizabeth M. Nolan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Manuela Raffatellu
- Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California San Diego, La Jolla, California, USA
- Center for Microbiome Innovation, University of California San Diego, La Jolla, California, USA
- Chiba University-University of California-San Diego Center for Mucosal Immunology, Allergy, and Vaccines (CU-UCSD cMAV), La Jolla, California, USA
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The Physiological Functions of AbrB on Sporulation, Biofilm Formation and Carbon Source Utilization in Clostridium tyrobutyricum. Bioengineering (Basel) 2022; 9:bioengineering9100575. [PMID: 36290543 PMCID: PMC9598496 DOI: 10.3390/bioengineering9100575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 11/17/2022] Open
Abstract
As a pleiotropic regulator, Antibiotic resistant protein B (AbrB) was reported to play important roles in various cellular processes in Bacilli and some Clostridia strains. In Clostridium tyrobutyricum, abrB (CTK_C 00640) was identified to encode AbrB by amino acid sequence alignment and functional domain prediction. The results of abrB deletion or overexpression in C. tyrobutyricum showed that AbrB not only exhibited the reported characteristics such as the negative regulation on sporulation, positive effects on biofilm formation and stress resistance but also exhibited new functions, especially the negative regulation of carbon metabolism. AbrB knockout strain (Ct/ΔabrB) could alleviate glucose-mediated carbon catabolite repression (CCR) and enhance the utilization of xylose compared with the parental strain, resulting in a higher butyrate titer (14.79 g/L vs. 7.91 g/L) and xylose utilization rate (0.19 g/L·h vs. 0.02 g/L·h) from the glucose and xylose mixture. This study confirmed the pleiotropic regulatory function of AbrB in C. tyrobutyricum, suggesting that Ct/ΔabrB was the potential candidate for butyrate production from abundant, renewable lignocellulosic biomass mainly composed of glucose and xylose.
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Nadalian B, Nadalian B, Houri H, Shahrokh S, Abdehagh M, Yadegar A, Ebrahimipour G. Phylogrouping and characterization of Escherichia coli isolated from colonic biopsies and fecal samples of patients with flare of inflammatory bowel disease in Iran. Front Med (Lausanne) 2022; 9:985300. [PMID: 36106322 PMCID: PMC9464868 DOI: 10.3389/fmed.2022.985300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 08/05/2022] [Indexed: 12/02/2022] Open
Abstract
Background Although the etiopathogenesis of inflammatory bowel disease (IBD) is still poorly understood, Escherichia coli has been described as a potential causative microorganism in IBD pathogenesis and also disease progression, offering a potential therapeutic target for disease management. Therefore, we conducted this study to investigate the pathotypes, phylogenetic groups, and antimicrobial resistance of E. coli isolates from patients with IBD in Iran. Methods Fecal and biopsy colonic samples were collected from IBD patients experiencing flare-up episodes referred to Taleghani hospital in Tehran, Iran, between August 2020 and January 2021. Identification of E. coli strains was performed based on biochemical and molecular methods. Antibiotic susceptibility testing was performed as recommended by the Clinical and Laboratory Standards Institute. Phylogrouping and pathotyping of each isolate were carried out using polymerase chain reaction (PCR) and multilocus sequence typing (MLST) assays. Results A total of 132 non-duplicate E. coli strains were isolated from 113 IBD patients, including 96 ulcerative colitis (UC), and 17 Crohn’s disease (CD) patients. In our study, 55% of CD-related E. coli and 70.5% of UC-related isolates were non-susceptible to at least three or more unique antimicrobial classes, and were considered as multidrug-resistant (MDR) strains. E. coli strains exhibited a high level of resistance to cefazolin, ampicillin, tetracycline, ceftazidime, ciprofloxacin, and cefotaxime. Enterotoxigenic E. coli (ETEC) and diffusely adherent E. coli (DAEC) were the most prevalent pathotypes, and groups B2 and D were the predominant phylogroups. Conclusion In the present study, we found that E. coli strains that colonize the gut of Iranian patients with IBD most frequently belonged to phylogenetic groups B2 and D. We also conclude that E. coli isolates from IBD patients have been revealed to be resistant to commonly used antibiotics, in which most of them harbored strains that would be categorized as MDR.
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Affiliation(s)
- Banafsheh Nadalian
- Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran
| | - Bahareh Nadalian
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hamidreza Houri
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Shabnam Shahrokh
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Abdehagh
- Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abbas Yadegar
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- *Correspondence: Abbas Yadegar, ;
| | - Gholamhossein Ebrahimipour
- Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran
- Gholamhossein Ebrahimipour,
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Inactivation of the Pyrimidine Biosynthesis pyrD Gene Negatively Affects Biofilm Formation and Virulence Determinants in the Crohn’s Disease-Associated Adherent Invasive Escherichia coli LF82 Strain. Microorganisms 2022; 10:microorganisms10030537. [PMID: 35336113 PMCID: PMC8956108 DOI: 10.3390/microorganisms10030537] [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: 01/24/2022] [Revised: 02/17/2022] [Accepted: 02/26/2022] [Indexed: 01/07/2023] Open
Abstract
In Crohn’s disease (CD) patients, the adherent-invasive Escherichia coli (AIEC) pathovar contributes to the chronic inflammation typical of the disease via its ability to invade gut epithelial cells and to survive in macrophages. We show that, in the AIEC strain LF82, inactivation of the pyrD gene, encoding dihydroorotate dehydrogenase (DHOD), an enzyme of the de novo pyrimidine biosynthetic pathway, completely abolished its ability of to grow in a macrophage environment-mimicking culture medium. In addition, pyrD inactivation reduced flagellar motility and strongly affected biofilm formation by downregulating transcription of both type 1 fimbriae and curli subunit genes. Thus, the pyrD gene appears to be essential for several cellular processes involved in AIEC virulence. Interestingly, vidofludimus (VF), a DHOD inhibitor, has been proposed as an effective drug in CD treatment. Despite displaying a potentially similar binding mode for both human and E. coli DHOD in computational molecular docking experiments, VF showed no activity on either growth or virulence-related processes in LF82. Altogether, our results suggest that the crucial role played by the pyrD gene in AIEC virulence, and the presence of structural differences between E. coli and human DHOD allowing for the design of specific inhibitors, make E. coli DHOD a promising target for therapeutical strategies aiming at counteracting chronic inflammation in CD by acting selectively on its bacterial triggers.
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de Dios R, Santero E, Reyes-Ramírez F. Extracytoplasmic Function σ Factors as Tools for Coordinating Stress Responses. Int J Mol Sci 2021; 22:ijms22083900. [PMID: 33918849 PMCID: PMC8103513 DOI: 10.3390/ijms22083900] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/05/2021] [Accepted: 04/07/2021] [Indexed: 01/03/2023] Open
Abstract
The ability of bacterial core RNA polymerase (RNAP) to interact with different σ factors, thereby forming a variety of holoenzymes with different specificities, represents a powerful tool to coordinately reprogram gene expression. Extracytoplasmic function σ factors (ECFs), which are the largest and most diverse family of alternative σ factors, frequently participate in stress responses. The classification of ECFs in 157 different groups according to their phylogenetic relationships and genomic context has revealed their diversity. Here, we have clustered 55 ECF groups with experimentally studied representatives into two broad classes of stress responses. The remaining 102 groups still lack any mechanistic or functional insight, representing a myriad of systems yet to explore. In this work, we review the main features of ECFs and discuss the different mechanisms controlling their production and activity, and how they lead to a functional stress response. Finally, we focus in more detail on two well-characterized ECFs, for which the mechanisms to detect and respond to stress are complex and completely different: Escherichia coli RpoE, which is the best characterized ECF and whose structural and functional studies have provided key insights into the transcription initiation by ECF-RNAP holoenzymes, and the ECF15-type EcfG, the master regulator of the general stress response in Alphaproteobacteria.
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10
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Viennois E, Bretin A, Dubé PE, Maue AC, Dauriat CJG, Barnich N, Gewirtz AT, Chassaing B. Dietary Emulsifiers Directly Impact Adherent-Invasive E. coli Gene Expression to Drive Chronic Intestinal Inflammation. Cell Rep 2020; 33:108229. [PMID: 33027647 PMCID: PMC7539532 DOI: 10.1016/j.celrep.2020.108229] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 07/30/2020] [Accepted: 09/14/2020] [Indexed: 02/07/2023] Open
Abstract
Dietary emulsifiers carboxymethylcellulose (CMC) and polysorbate-80 (P80) disturb gut microbiota, promoting chronic inflammation. Mice with minimal microbiota are protected against emulsifiers’ effects, leading us to hypothesize that these compounds might provoke select pathobionts to promote inflammation. Gnotobiotic wild-type (WT) and interleukin-10 (IL-10)−/− mice were colonized with Crohn’s-disease-associated adherent-invasive E. coli (AIEC) and subsequently administered CMC or P80. AIEC colonization of GF and altered Schaedler flora (ASF) mice results in chronic intestinal inflammation and metabolism dysregulations when consuming the emulsifier. In IL-10−/− mice, AIEC mono-colonization results in severe intestinal inflammation in response to emulsifiers. Exposure of AIEC to emulsifiers in vitro increases its motility and ability to adhere to intestinal epithelial cells. Transcriptomic analysis reveals that emulsifiers directly induce expression of clusters of genes that mediate AIEC virulence and promotion of inflammation. To conclude, emulsifiers promote virulence and encroachment of pathobionts, providing a means by which these compounds may drive inflammation in hosts carrying such bacteria. Dietary emulsifiers alter the intestinal microbiota, promoting chronic inflammation Select pathobionts are required to mediate the detrimental effects of emulsifiers Emulsifiers directly induce the expression of bacterial virulence genes Microbiota-based dietary intervention appears warranted
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Affiliation(s)
- Emilie Viennois
- INSERM, U1149, Center of Research on Inflammation, Université de Paris, Paris, France; Institute for Biomedical Sciences, Center for Inflammation, Immunity and Infection, Digestive Disease Research Group, Georgia State University, Atlanta, GA, USA
| | - Alexis Bretin
- Institute for Biomedical Sciences, Center for Inflammation, Immunity and Infection, Digestive Disease Research Group, Georgia State University, Atlanta, GA, USA
| | | | | | - Charlène J G Dauriat
- INSERM U1016, team "Mucosal microbiota in chronic inflammatory diseases", CNRS UMR 8104, Université de Paris, Paris, France
| | - Nicolas Barnich
- Université Clermont Auvergne/Inserm U1071 USC-INRA 2018, Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte (M2iSH), Clermont-Ferrand, France
| | - Andrew T Gewirtz
- Institute for Biomedical Sciences, Center for Inflammation, Immunity and Infection, Digestive Disease Research Group, Georgia State University, Atlanta, GA, USA
| | - Benoit Chassaing
- Institute for Biomedical Sciences, Center for Inflammation, Immunity and Infection, Digestive Disease Research Group, Georgia State University, Atlanta, GA, USA; INSERM U1016, team "Mucosal microbiota in chronic inflammatory diseases", CNRS UMR 8104, Université de Paris, Paris, France; Neuroscience Institute, Georgia State University, Atlanta, GA, USA.
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11
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Camprubí-Font C, Martinez-Medina M. Why the discovery of adherent-invasive Escherichia coli molecular markers is so challenging? World J Biol Chem 2020; 11:1-13. [PMID: 32405343 PMCID: PMC7205867 DOI: 10.4331/wjbc.v11.i1.1] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/18/2020] [Accepted: 03/31/2020] [Indexed: 02/05/2023] Open
Abstract
Adherent-invasive Escherichia coli (AIEC) strains have been extensively related to Crohn’s disease (CD) etiopathogenesis. Higher AIEC prevalence in CD patients versus controls has been reported, and its mechanisms of pathogenicity have been linked to CD physiopathology. In CD, the therapeutic armamentarium remains limited and non-curative; hence, the necessity to better understand AIEC as a putative instigator or propagator of the disease is certain. Nonetheless, AIEC identification is currently challenging because it relies on phenotypic assays based on infected cell cultures which are highly time-consuming, laborious and non-standardizable. To address this issue, AIEC molecular mechanisms and virulence genes have been studied; however, a specific and widely distributed genetic AIEC marker is still missing. The finding of molecular tools to easily identify AIEC could be useful in the identification of AIEC carriers who could profit from personalized treatment. Also, it would significantly promote AIEC epidemiological studies. Here, we reviewed the existing data regarding AIEC genetics and presented those molecular markers that could assist with AIEC identification. Finally, we highlighted the problems behind the discovery of exclusive AIEC biomarkers and proposed strategies to facilitate the search of AIEC signature sequences.
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Affiliation(s)
- Carla Camprubí-Font
- Laboratory of Molecular Microbiology, Department of Biology, University of Girona, Girona 17003, Spain
| | - Margarita Martinez-Medina
- Laboratory of Molecular Microbiology, Department of Biology, University of Girona, Girona 17003, Spain
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12
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Fang C, Li L, Shen L, Shi J, Wang S, Feng Y, Zhang Y. Structures and mechanism of transcription initiation by bacterial ECF factors. Nucleic Acids Res 2020; 47:7094-7104. [PMID: 31131408 PMCID: PMC6648896 DOI: 10.1093/nar/gkz470] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 05/09/2019] [Accepted: 05/17/2019] [Indexed: 01/25/2023] Open
Abstract
Bacterial RNA polymerase (RNAP) forms distinct holoenzymes with extra-cytoplasmic function (ECF) σ factors to initiate specific gene expression programs. In this study, we report a cryo-EM structure at 4.0 Å of Escherichia coli transcription initiation complex comprising σE-the most-studied bacterial ECF σ factor (Ec σE-RPo), and a crystal structure at 3.1 Å of Mycobacterium tuberculosis transcription initiation complex with a chimeric σH/E (Mtb σH/E-RPo). The structure of Ec σE-RPo reveals key interactions essential for assembly of E. coli σE-RNAP holoenzyme and for promoter recognition and unwinding by E. coli σE. Moreover, both structures show that the non-conserved linkers (σ2/σ4 linker) of the two ECF σ factors are inserted into the active-center cleft and exit through the RNA-exit channel. We performed secondary-structure prediction of 27,670 ECF σ factors and find that their non-conserved linkers probably reach into and exit from RNAP active-center cleft in a similar manner. Further biochemical results suggest that such σ2/σ4 linker plays an important role in RPo formation, abortive production and promoter escape during ECF σ factors-mediated transcription initiation.
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Affiliation(s)
- Chengli Fang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lingting Li
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liqiang Shen
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Shi
- Department of Biochemistry and Molecular Biology, School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Sheng Wang
- Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST) Thuwal, 23955, Saudi Arabia
| | - Yu Feng
- Department of Biochemistry and Molecular Biology, School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Yu Zhang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
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13
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Hews CL, Cho T, Rowley G, Raivio TL. Maintaining Integrity Under Stress: Envelope Stress Response Regulation of Pathogenesis in Gram-Negative Bacteria. Front Cell Infect Microbiol 2019; 9:313. [PMID: 31552196 PMCID: PMC6737893 DOI: 10.3389/fcimb.2019.00313] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 08/19/2019] [Indexed: 12/20/2022] Open
Abstract
The Gram-negative bacterial envelope is an essential interface between the intracellular and harsh extracellular environment. Envelope stress responses (ESRs) are crucial to the maintenance of this barrier and function to detect and respond to perturbations in the envelope, caused by environmental stresses. Pathogenic bacteria are exposed to an array of challenging and stressful conditions during their lifecycle and, in particular, during infection of a host. As such, maintenance of envelope homeostasis is essential to their ability to successfully cause infection. This review will discuss our current understanding of the σE- and Cpx-regulated ESRs, with a specific focus on their role in the virulence of a number of model pathogens.
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Affiliation(s)
- Claire L Hews
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Timothy Cho
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Gary Rowley
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Tracy L Raivio
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
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14
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Levine A, Kori M, Kierkus J, Sigall Boneh R, Sladek M, Escher JC, Wine E, Yerushalmi B, Amil Dias J, Shaoul R, Veereman Wauters G, Boaz M, Abitbol G, Bousvaros A, Turner D. Azithromycin and metronidazole versus metronidazole-based therapy for the induction of remission in mild to moderate paediatric Crohn's disease : a randomised controlled trial. Gut 2019; 68:239-247. [PMID: 29420227 DOI: 10.1136/gutjnl-2017-315199] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 12/17/2017] [Accepted: 12/21/2017] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Crohn's disease (CD) pathogenesis associated with dysbiosis and presence of pathobionts in the lumen, intracellular compartments and epithelial biofilms. Azithromycin is active in all three compartments. Our goal was to evaluate if azithromycin-based therapy can improve response and induce remission compared with metronidazole alone in paediatric CD. DESIGN This blinded randomised controlled trial allocated children 5-18 years with 10<Pediatric Crohn's Disease Activity Index (PCDAI)≤40 to azithromycin 7.5 mg/kg, 5 days/week for 4 weeks and 3 days/week for another 4 weeks with metronidazole 20 mg/kg/day (group 1) or metronidazole alone (group 2), daily for 8 weeks. Failures from group 2 were offered azithromycin as open label. The primary end point was response defined by a decrease in PCDAI>12.5 or remission using intention to treat analysis. RESULTS 73 patients (mean age 13.8±3.1 years) were enrolled, 35 to group 1 and 38 to group 2. Response and remission rates at week 8 were identical 23/35 (66%) in group 1 and 17/38 (45%) and 15/38 (39%) in group 2 (P=0.07 and P=0.025, respectively). The needed to treat for remission was 3.7. Faecal calprotectin declined significantly in group 1 (P=0.003) but not in group 2 (p=0.33), and was lower at week 8 (P=0.052). Additional therapy was required in 6/35(17%) from group 1 versus 16/38(42%) in group 2 (P=0.027) by week 8. Among 12 failures in group 2, open-label azithromycin led to remission in 10/12 (83%). CONCLUSIONS The combination of azithromycin and metronidazole failed to improve response but was superior for induction of remission and reduction in calprotectin. TRIAL REGISTRATION NUMBER NCT01596894.
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Affiliation(s)
- Arie Levine
- Pediatric Gastroenterology and Nutrition Unit, Wolfson Medical Center, Holon, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Michal Kori
- Pediatric Day Care Unit, Kaplan Medical Center, Rehovot, Israel
| | - Jarek Kierkus
- Department of Gastroenterology, Hepatology, Feeding Disorders and Pediatrics, The Children's Memorial Health Institute, Warsaw, Poland
| | - Rotem Sigall Boneh
- Pediatric Gastroenterology and Nutrition Unit, Wolfson Medical Center, Holon, Israel
| | - Malgorzata Sladek
- Department of Pediatrics, Gastroenterology and Nutrition, Jagiellonian University Medical College, Cracow, Poland
| | - Johanna C Escher
- Department of Pediatric Gastroenterology, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Eytan Wine
- Division of Pediatric Gastroenterology, Department of Pediatrics, University of Alberta, Edmonton, Canada
| | - Baruch Yerushalmi
- Pediatric Gastroenterology Unit, Soroka University Medical Center, Beersheba, Israel.,Faculty of Health Sciences, Ben-Gurion University of the Negev, Negev, Israel
| | | | - Ron Shaoul
- Pediatric Gastroenterology Unit, Ruth Children's Hospital, Rambam Medical Center, Brussels, Belgium
| | | | - Mona Boaz
- Department of Nutrition School of Health Sciences, Ariel University, Ariel, Israel.,Epidemiology and Research Unit, E. Wolfson Medical Center, Holon, Israel
| | - Guila Abitbol
- Pediatric Gastroenterology Lab, The Juliet Keidan Institute of Paediatric Gastroenterology, Hepatology, and Nutrition, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Athos Bousvaros
- Division of Gastroenterology and Nutrition, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Dan Turner
- The Juliet Keidan Institute of Pediatric Gastroenterology and Nutrition, Shaare Zedek Medical Center, The Hebrew University of Jerusalem, Jerusalem, Israel
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15
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Migliore F, Macchi R, Landini P, Paroni M. Phagocytosis and Epithelial Cell Invasion by Crohn's Disease-Associated Adherent-Invasive Escherichia coli Are Inhibited by the Anti-inflammatory Drug 6-Mercaptopurine. Front Microbiol 2018; 9:964. [PMID: 29867868 PMCID: PMC5961443 DOI: 10.3389/fmicb.2018.00964] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 04/24/2018] [Indexed: 12/22/2022] Open
Abstract
Adherent-invasive Escherichia coli (AIEC) strains are overrepresented in the dysbiotic microbiota of Crohn’s disease (CD) patients, and contribute to the onset of the chronic inflammation typical of the disease. However, the effects of anti-inflammatory drugs used for CD treatment on AIEC virulence have not yet been investigated. In this report, we show that exposure of AIEC LF82 strain to amino-6-mercaptopurine (6-MP) riboside, one of the most widely used anti-inflammatory drugs in CD, impairs its ability to adhere to, and consequently to invade, human epithelial cells. Notably, phagocytosis of LF82 treated with 6-MP by human macrophages is also reduced, suggesting that 6-MP affects AIEC cell surface determinants involved both in interaction with epithelial cells and in uptake by macrophages. Since a main target of 6-MP in bacterial cells is the inhibition of the important signal molecule c-di-GMP, we also tested whether perturbations in cAMP, another major signaling pathway in E. coli, might have similar effects on interactions with human cells. To this aim, we grew LF82 in the presence of glucose, which leads to inhibition of cAMP synthesis. Growth in glucose-supplemented medium resulted in a reduction in AIEC adhesion to epithelial cells and uptake by macrophages. Consistent with these results, both 6-MP and glucose can affect expression of cell adhesion-related genes, such as the csg genes, encoding thin aggregative fimbriae (curli). In addition, glucose strongly inhibits expression of the fim operon, encoding type 1 pili, a known AIEC determinant for adhesion to human cells. To further investigate whether 6-MP can indeed inhibit c-di-GMP signaling in AIEC, we performed biofilm and motility assays and determination of extracellular polysaccharides. 6-MP clearly affected biofilm formation and cellulose production, but also, unexpectedly, reduced cell motility, itself an important virulence factor for AIEC. Our results provide strong evidence that 6-MP can affect AIEC-host cell interaction by acting on the bacterial cell, thus strengthening the hypothesis that mercaptopurines might promote CD remission also by affecting gut microbiota composition and/or physiology, and suggesting that novel drugs targeting bacterial virulence and signaling might be effective in preventing chronic inflammation in CD.
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Affiliation(s)
- Federica Migliore
- Dipartimento di Bioscienze, Università degli studi di Milano, Milan, Italy
| | - Raffaella Macchi
- Dipartimento di Bioscienze, Università degli studi di Milano, Milan, Italy
| | - Paolo Landini
- Dipartimento di Bioscienze, Università degli studi di Milano, Milan, Italy
| | - Moira Paroni
- Dipartimento di Bioscienze, Università degli studi di Milano, Milan, Italy
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16
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Palmela C, Chevarin C, Xu Z, Torres J, Sevrin G, Hirten R, Barnich N, Ng SC, Colombel JF. Adherent-invasive Escherichia coli in inflammatory bowel disease. Gut 2018; 67:574-587. [PMID: 29141957 DOI: 10.1136/gutjnl-2017-314903] [Citation(s) in RCA: 309] [Impact Index Per Article: 51.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 09/20/2017] [Accepted: 10/28/2017] [Indexed: 02/06/2023]
Abstract
Intestinal microbiome dysbiosis has been consistently described in patients with IBD. In the last decades, Escherichia coli, and the adherent-invasive E coli (AIEC) pathotype in particular, has been implicated in the pathogenesis of IBD. Since the discovery of AIEC, two decades ago, progress has been made in unravelling these bacteria characteristics and its interaction with the gut immune system. The mechanisms of adhesion of AIEC to intestinal epithelial cells (via FimH and cell adhesion molecule 6) and its ability to escape autophagy when inside macrophages are reviewed here. We also explore the existing data on the prevalence of AIEC in patients with Crohn's disease and UC, and the association between the presence of AIEC and disease location, activity and postoperative recurrence. Finally, we highlight potential therapeutic strategies targeting AIEC colonisation of gut mucosa, including the use of phage therapy, bacteriocins and antiadhesive molecules. These strategies may open new avenues for the prevention and treatment of IBD in the future.
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Affiliation(s)
- Carolina Palmela
- Division of Gastroenterology, Icahn School of Medicine at Mount Sinai, New York City, New York, USA.,Division of Gastroenterology, Hospital Beatriz Ângelo, Loures, Portugal
| | - Caroline Chevarin
- Université Clermont Auvergne, Inserm U1071, USC-INRA 2018, M2iSH, CRNH Auvergne, F-63000 Clermont-Ferrand, France
| | - Zhilu Xu
- Department of Medicine and Therapeutics, Institute of Digestive Diseases, LKS Institute of Health Science, State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, China
| | - Joana Torres
- Division of Gastroenterology, Icahn School of Medicine at Mount Sinai, New York City, New York, USA.,Division of Gastroenterology, Hospital Beatriz Ângelo, Loures, Portugal
| | - Gwladys Sevrin
- Université Clermont Auvergne, Inserm U1071, USC-INRA 2018, M2iSH, CRNH Auvergne, F-63000 Clermont-Ferrand, France
| | - Robert Hirten
- Division of Gastroenterology, Icahn School of Medicine at Mount Sinai, New York City, New York, USA
| | - Nicolas Barnich
- Université Clermont Auvergne, Inserm U1071, USC-INRA 2018, M2iSH, CRNH Auvergne, F-63000 Clermont-Ferrand, France
| | - Siew C Ng
- Department of Medicine and Therapeutics, Institute of Digestive Diseases, LKS Institute of Health Science, State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, China
| | - Jean-Frederic Colombel
- Division of Gastroenterology, Icahn School of Medicine at Mount Sinai, New York City, New York, USA
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17
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Vila J, Sáez-López E, Johnson JR, Römling U, Dobrindt U, Cantón R, Giske CG, Naas T, Carattoli A, Martínez-Medina M, Bosch J, Retamar P, Rodríguez-Baño J, Baquero F, Soto SM. Escherichia coli: an old friend with new tidings. FEMS Microbiol Rev 2018; 40:437-463. [PMID: 28201713 DOI: 10.1093/femsre/fuw005] [Citation(s) in RCA: 175] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 09/23/2015] [Accepted: 02/04/2016] [Indexed: 12/16/2022] Open
Abstract
Escherichia coli is one of the most-studied microorganisms worldwide but its characteristics are continually changing. Extraintestinal E. coli infections, such as urinary tract infections and neonatal sepsis, represent a huge public health problem. They are caused mainly by specialized extraintestinal pathogenic E. coli (ExPEC) strains that can innocuously colonize human hosts but can also cause disease upon entering a normally sterile body site. The virulence capability of such strains is determined by a combination of distinctive accessory traits, called virulence factors, in conjunction with their distinctive phylogenetic background. It is conceivable that by developing interventions against the most successful ExPEC lineages or their key virulence/colonization factors the associated burden of disease and health care costs could foreseeably be reduced in the future. On the other hand, one important problem worldwide is the increase of antimicrobial resistance shown by bacteria. As underscored in the last WHO global report, within a wide range of infectious agents including E. coli, antimicrobial resistance has reached an extremely worrisome situation that ‘threatens the achievements of modern medicine’. In the present review, an update of the knowledge about the pathogenicity, antimicrobial resistance and clinical aspects of this ‘old friend’ was presented.
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Affiliation(s)
- J Vila
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
- Department of Clinical Microbiology, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain
- Spanish Network for Research in Infectious Diseases (REIPI), Instituto de Salud Carlos III, Madrid, Spain
| | - E Sáez-López
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - J R Johnson
- VA Medical Center, Minneapolis, MN, USA, and University of Minnesota, Minneapolis, MN, USA
| | - U Römling
- Karolinska Institute, Stockholm, Sweden
| | - U Dobrindt
- Institute of Hygiene, University of Münster, Münster, Germany
| | - R Cantón
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto de Investigación Sanitaria (IRYCIS), Madrid, Spain
- Spanish Network for Research in Infectious Diseases (REIPI), Instituto de Salud Carlos III, Madrid, Spain
| | - C G Giske
- Karolinska Institute, Stockholm, Sweden
| | - T Naas
- Hôpital de Bicêtre, Université Paris Sud, Le Kremlin-Bicêtre, France
| | - A Carattoli
- Department of infectious, parasitic and immune-mediated diseases, Istituto Superiore di Sanità, Rome, Italy
| | - M Martínez-Medina
- Laboratory of Molecular Microbiology, Department of Biology, University of Girona, Girona, Spain
| | - J Bosch
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
- Department of Clinical Microbiology, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain
| | - P Retamar
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospitales Universitarios Virgen Macarena y Virgen del Rocío, Departamento de Medicina, Universidad de Sevilla, Seville, Spain
| | - J Rodríguez-Baño
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospitales Universitarios Virgen Macarena y Virgen del Rocío, Departamento de Medicina, Universidad de Sevilla, Seville, Spain
- Spanish Network for Research in Infectious Diseases (REIPI), Instituto de Salud Carlos III, Madrid, Spain
| | - F Baquero
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - S M Soto
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
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18
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Exosomes Released from Cells Infected with Crohn's Disease-associated Adherent-Invasive Escherichia coli Activate Host Innate Immune Responses and Enhance Bacterial Intracellular Replication. Inflamm Bowel Dis 2016; 22:516-28. [PMID: 26595556 DOI: 10.1097/mib.0000000000000635] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Crohn's disease is a chronic inflammatory bowel disease, of which the etiology involves environmental, genetic, and microbial factors. A high prevalence of adherent-invasive Escherichia coli, named AIEC, has been reported in the intestinal mucosa of patients with Crohn's disease. Exosomes are extracellular vesicles that function in intercellular communication and have been implicated in host responses to intracellular pathogens. We investigated the potential involvement of exosomes in host response to AIEC infection. METHODS Human intestinal epithelial T84 cells, THP-1 macrophages, and CEABAC10 transgenic mice were infected with the AIEC reference strain LF82 or the nonpathogenic E. coli K-12 MG1655 strain. Exosomes were purified using the ExoQuick reagent. RESULTS LF82 infection induced the release of exosomes by T84 and THP-1 cells. Compared with exosomes released from the uninfected or MG1655-infected T84 cells, those released from LF82-infected cells activated nuclear factor-kappa B, mitogen-activated protein kinases p38, and c-Jun N-terminal kinase and increased the secretion of proinflammatory cytokines in naive THP-1 macrophages. LF82 infection of THP-1 macrophages also induced the release of exosomes that triggered a proinflammatory response in recipient THP-1 cells. Importantly, stimulation of T84 or THP-1 cells with exosomes released from LF82-infected cells increased LF82 intracellular replication compared with stimulation with exosomes secreted by uninfected cells. Exosomes purified from intestinal lumen of CEABAC10 transgenic mice infected with LF82 increased proinflammatory responses in murine RAW 264.7 macrophages compared with those from uninfected or MG1655-infected mice. CONCLUSIONS Exosomes are new mediators of host-AIEC interaction with their capacity to activate innate immune responses and subvert the control of AIEC replication.
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19
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Ocvirk S, Sava IG, Lengfelder I, Lagkouvardos I, Steck N, Roh JH, Tchaptchet S, Bao Y, Hansen JJ, Huebner J, Carroll IM, Murray BE, Sartor RB, Haller D. Surface-Associated Lipoproteins Link Enterococcus faecalis Virulence to Colitogenic Activity in IL-10-Deficient Mice Independent of Their Expression Levels. PLoS Pathog 2015; 11:e1004911. [PMID: 26067254 PMCID: PMC4466351 DOI: 10.1371/journal.ppat.1004911] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 04/24/2015] [Indexed: 12/22/2022] Open
Abstract
The commensal Enterococcus faecalis is among the most common causes of nosocomial infections. Recent findings regarding increased abundance of enterococci in the intestinal microbiota of patients with inflammatory bowel diseases and induction of colitis in IL-10-deficient (IL-10-/-) mice put a new perspective on the contribution of E. faecalis to chronic intestinal inflammation. Based on the expression of virulence-related genes in the inflammatory milieu of IL-10-/- mice using RNA-sequencing analysis, we characterized the colitogenic role of two bacterial structures that substantially impact on E. faecalis virulence by different mechanisms: the enterococcal polysaccharide antigen and cell surface-associated lipoproteins. Germ-free wild type and IL-10-/- mice were monoassociated with E. faecalis wild type OG1RF or the respective isogenic mutants for 16 weeks. Intestinal tissue and mesenteric lymph nodes (MLN) were collected to characterize tissue pathology, loss of intestinal barrier function, bacterial adhesion to intestinal epithelium and immune cell activation. Bone marrow-derived dendritic cells (BMDC) were stimulated with bacterial lysates and E. faecalis virulence was additionally investigated in three invertebrate models. Colitogenic activity of wild type E. faecalis (OG1RF score: 7.2±1.2) in monoassociated IL-10-/- mice was partially impaired in E. faecalis lacking enterococcal polysaccharide antigen (ΔepaB score: 4.7±2.3; p<0.05) and was almost completely abrogated in E. faecalis deficient for lipoproteins (Δlgt score: 2.3±2.3; p<0.0001). Consistently both E. faecalis mutants showed significantly impaired virulence in Galleria mellonella and Caenorhabditis elegans. Loss of E-cadherin in the epithelium was shown for all bacterial strains in inflamed IL-10-/- but not wild type mice. Inactivation of epaB in E. faecalis reduced microcolony and biofilm formation in vitro, altered bacterial adhesion to intestinal epithelium of germ-free Manduca sexta larvae and impaired penetration into the colonic mucus layer of IL-10-/- mice. Lipoprotein-deficient E. faecalis exhibited an impaired TLR2-mediated activation of BMDCs in vitro despite their ability to fully reactivate MLN cells as well as MLN-derived colitogenic T cells ex vivo. E. faecalis virulence factors accounting for bacterial adhesion to mucosal surfaces as well as intestinal barrier disruption partially contribute to colitogenic activity of E. faecalis. Beyond their well-known role in infections, cell surface-associated lipoproteins are essential structures for colitogenic activity of E. faecalis by mediating innate immune cell activation. Enterococcus faecalis is a commensal of the human intestinal core microbiota harboring several putative virulence factors, which highlight its role as opportunistic pathogen. This dualistic character is supported by recent evidence linking Enterococcus spp. to the pathogenesis of inflammatory bowel diseases (IBD). Although several studies suggest a crucial role for opportunistic pathogens in IBD pathogenesis targeting genetically susceptible individuals, the dynamic relationship between disease-relevant host compartments and specific bacterial structures able to trigger intestinal inflammation remain unclear. Here, we report that cell surface-associated lipoproteins and the enterococcal polysaccharide antigen, which are relevant for E. faecalis virulence in invertebrate infection models, but whose expression is minimally affected by the intestinal inflammatory milieu, exhibit colitogenic activity in a mouse model susceptible for chronic colitis. Bacterial lipoproteins trigger innate immune cell activation and are a critical prerequisite for E. faecalis-induced colitis. The enterococcal polysaccharide antigen mediates bacterial mucus penetration and adhesion to mucosal surfaces, promotes the formation of biofilm and contributes to E. faecalis colitogenic activity. Using E. faecalis as a model organism, we demonstrate that colitogenic activity of opportunistic pathogens can be assigned to specific bacterial structures, a finding that may help to identify the most essential steps in IBD-related microbe-host interactions.
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Affiliation(s)
- Soeren Ocvirk
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
| | - Irina G. Sava
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
| | - Isabella Lengfelder
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
| | - Ilias Lagkouvardos
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
| | - Natalie Steck
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
| | - Jung H. Roh
- Division of Infectious Diseases, Department of Internal Medicine, The University of Texas Medical School, Houston, Texas, United States of America
| | - Sandrine Tchaptchet
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Yinyin Bao
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Freiburg, Germany
| | - Jonathan J. Hansen
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Johannes Huebner
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Freiburg, Germany
| | - Ian M. Carroll
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Barbara E. Murray
- Division of Infectious Diseases, Department of Internal Medicine, The University of Texas Medical School, Houston, Texas, United States of America
| | - R. Balfour Sartor
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Dirk Haller
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
- * E-mail:
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20
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Affiliation(s)
- Ye Yang
- Department of Medicine, University of Florida, Gainesville, FL, USA
| | - Christian Jobin
- Department of Medicine, University of Florida, Gainesville, FL, USA Department of Infectious Diseases and Pathology, University of Florida, Gainesville, FL, USA
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21
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Analysis of the σE regulon in Crohn's disease-associated Escherichia coli revealed involvement of the waaWVL operon in biofilm formation. J Bacteriol 2015; 197:1451-65. [PMID: 25666140 DOI: 10.1128/jb.02499-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
UNLABELLED Ileal lesions of patients with Crohn's disease are colonized by adherent-invasive Escherichia coli (AIEC), which is able to adhere to and to invade intestinal epithelial cells (IEC), to replicate within macrophages, and to form biofilms on the surface of the intestinal mucosa. Previous analyses indicated the involvement of the σ(E) pathway in AIEC-IEC interaction, as well as in biofilm formation, with σ(E) pathway inhibition leading to an impaired ability of AIEC to colonize the intestinal mucosa and to form biofilms. The aim of this study was to characterize the σ(E) regulon of AIEC strain LF82 in order to identify members involved in AIEC phenotypes. Using comparative in silico analysis of the σ(E) regulon, we identified the waaWVL operon as a new member of the σ(E) regulon in reference AIEC strain LF82. We determined that the waaWVL operon is involved in AIEC lipopolysaccharide structure and composition, and the waaWVL operon was found to be essential for AIEC strains to produce biofilm and to colonize the intestinal mucosa. IMPORTANCE An increased prevalence of adherent-invasive Escherichia coli (AIEC) bacteria was previously observed in the intestinal mucosa of Crohn's disease (CD) patients, and clinical observations revealed bacterial biofilms associated with the mucosa of CD patients. Here, analysis of the σ(E) regulon in AIEC and commensal E. coli identified 12 genes controlled by σ(E) only in AIEC. Among them, WaaWVL factors were found to play an essential role in biofilm formation and mucosal colonization by AIEC. In addition to identifying molecular tools that revealed a pathogenic population of E. coli colonizing the mucosa of CD patients, these results indicate that targeting the waaWVL operon could be a potent therapeutic strategy to interfere with the ability of AIEC to form biofilms and to colonize the gut mucosa.
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22
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Identification of inhibitors of a bacterial sigma factor using a new high-throughput screening assay. Antimicrob Agents Chemother 2014; 59:193-205. [PMID: 25331704 DOI: 10.1128/aac.03979-14] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Gram-negative bacteria are formidable pathogens because their cell envelope presents an adaptable barrier to environmental and host-mediated challenges. The stress response pathway controlled by the alternative sigma factor σ(E) is critical for maintenance of the cell envelope. Because σ(E) is required for the virulence or viability of several Gram-negative pathogens, it might be a useful target for antibiotic development. To determine if small molecules can inhibit the σ(E) pathway, and to permit high-throughput screening for antibiotic lead compounds, a σ(E) activity assay that is compatible with high-throughput screening was developed and validated. The screen employs a biological assay with positive readout. An Escherichia coli strain was engineered to express yellow fluorescent protein (YFP) under negative regulation by the σ(E) pathway, such that inhibitors of the pathway increase the production of YFP. To validate the screen, the reporter strain was used to identify σ(E) pathway inhibitors from a library of cyclic peptides. Biochemical characterization of one of the inhibitory cyclic peptides showed that it binds σ(E), inhibits RNA polymerase holoenzyme formation, and inhibits σ(E)-dependent transcription in vitro. These results demonstrate that alternative sigma factors can be inhibited by small molecules and enable high-throughput screening for inhibitors of the σ(E) pathway.
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Carrière J, Darfeuille-Michaud A, Nguyen HTT. Infectious etiopathogenesis of Crohn’s disease. World J Gastroenterol 2014; 20:12102-12117. [PMID: 25232246 PMCID: PMC4161797 DOI: 10.3748/wjg.v20.i34.12102] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 04/18/2014] [Accepted: 05/26/2014] [Indexed: 02/07/2023] Open
Abstract
Important advances during the last decade have been made in understanding the complex etiopathogenesis of Crohn’s disease (CD). While many gaps in our knowledge still exist, it has been suggested that the etiology of CD is multifactorial including genetic, environmental and infectious factors. The most widely accepted theory states that CD is caused by an aggressive immune response to infectious agents in genetically predisposed individuals. The rise of genome-wide association studies allowed the identification of loci and genetic variants in several components of host innate and adaptive immune responses to microorganisms in the gut, highlighting an implication of intestinal microbiota in CD etiology. Moreover, numerous independent studies reported a dysbiosis, i.e., a modification of intestinal microbiota composition, with an imbalance between the abundance of beneficial and harmful bacteria. Although microorganisms including viruses, yeasts, fungi and bacteria have been postulated as potential CD pathogens, based on epidemiological, clinicopathological, genetic and experimental evidence, their precise role in this disease is not clearly defined. This review summarizes the current knowledge of the infectious agents associated with an increased risk of developing CD. Therapeutic approaches to modulate the intestinal dysbiosis and to target the putative CD-associated pathogens, as well as their potential mechanisms of action are also discussed.
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Martinez-Medina M, Garcia-Gil LJ. Escherichia coli in chronic inflammatory bowel diseases: An update on adherent invasive Escherichia coli pathogenicity. World J Gastrointest Pathophysiol 2014; 5:213-227. [PMID: 25133024 PMCID: PMC4133521 DOI: 10.4291/wjgp.v5.i3.213] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/08/2014] [Accepted: 05/29/2014] [Indexed: 02/07/2023] Open
Abstract
Escherichia coli (E. coli), and particularly the adherent invasive E. coli (AIEC) pathotype, has been increasingly implicated in the ethiopathogenesis of Crohn’s disease (CD). E. coli strains with similar pathogenic features to AIEC have been associated with other intestinal disorders such as ulcerative colitis, colorectal cancer, and coeliac disease, but AIEC prevalence in these diseases remains largely unexplored. Since AIEC was described one decade ago, substantial progress has been made in deciphering its mechanisms of pathogenicity. However, the molecular bases that characterize the phenotypic properties of this pathotype are still not well resolved. A review of studies focused on E. coli populations in inflammatory bowel disease (IBD) is presented here and we discuss about the putative role of this species on each IBD subtype. Given the relevance of AIEC in CD pathogenesis, we present the latest research findings concerning AIEC host-microbe interactions and pathogenicity. We also review the existing data regarding the prevalence and abundance of AIEC in CD and its association with other intestinal diseases from humans and animals, in order to discuss the AIEC disease- and host-specificity. Finally, we highlight the fact that dietary components frequently found in industrialized countries may enhance AIEC colonization in the gut, which merits further investigation and the implementation of preventative measures.
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Raisch J, Buc E, Bonnet M, Sauvanet P, Vazeille E, de Vallée A, Déchelotte P, Darcha C, Pezet D, Bonnet R, Bringer MA, Darfeuille-Michaud A. Colon cancer-associated B2 Escherichia coli colonize gut mucosa and promote cell proliferation. World J Gastroenterol 2014; 20:6560-6572. [PMID: 24914378 PMCID: PMC4047342 DOI: 10.3748/wjg.v20.i21.6560] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 02/10/2014] [Accepted: 03/10/2014] [Indexed: 02/06/2023] Open
Abstract
AIM: To provide further insight into the characterization of mucosa-associated Escherichia coli (E. coli) isolated from the colonic mucosa of cancer patients.
METHODS: Phylogroups and the presence of cyclomodulin-encoding genes of mucosa-associated E. coli from colon cancer and diverticulosis specimens were determined by PCR. Adhesion and invasion experiments were performed with I-407 intestinal epithelial cells using gentamicin protection assay. Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) expression in T84 intestinal epithelial cells was measured by enzyme-linked immunosorbent assay and by Western Blot. Gut colonization, inflammation and pro-carcinogenic potential were assessed in a chronic infection model using CEABAC10 transgenic mice. Cell proliferation was analyzed by real-time mRNA quantification of PCNA and immunohistochemistry staining of Ki67.
RESULTS: Analysis of mucosa-associated E. coli from colon cancer and diverticulosis specimens showed that whatever the origin of the E. coli strains, 86% of cyclomodulin-positive E. coli belonged to B2 phylogroup and most harbored polyketide synthase (pks) island, which encodes colibactin, and/or cytotoxic necrotizing factor (cnf) genes. In vitro assays using I-407 intestinal epithelial cells revealed that mucosa-associated B2 E. coli strains were poorly adherent and invasive. However, mucosa-associated B2 E. coli similarly to Crohn’s disease-associated E. coli are able to induce CEACAM6 expression in T84 intestinal epithelial cells. In addition, in vivo experiments using a chronic infection model of CEACAM6 expressing mice showed that B2 E. coli strain 11G5 isolated from colon cancer is able to highly persist in the gut, and to induce colon inflammation, epithelial damages and cell proliferation.
CONCLUSION: In conclusion, these data bring new insights into the ability of E. coli isolated from patients with colon cancer to establish persistent colonization, exacerbate inflammation and trigger carcinogenesis.
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Carroll IM, Maharshak N. Enteric bacterial proteases in inflammatory bowel disease- pathophysiology and clinical implications. World J Gastroenterol 2013; 19:7531-7543. [PMID: 24431894 PMCID: PMC3837251 DOI: 10.3748/wjg.v19.i43.7531] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 10/05/2013] [Accepted: 11/05/2013] [Indexed: 02/06/2023] Open
Abstract
Numerous reports have identified a dysbiosis in the intestinal microbiota in patients suffering from inflammatory bowel diseases (IBD), yet the mechanism(s) in which this complex microbial community initiates or perpetuates inflammation remains unclear. The purpose of this review is to present evidence for one such mechanism that implicates enteric microbial derived proteases in the pathogenesis of IBD. We highlight and discuss studies demonstrating that proteases and protease receptors are abundant in the digestive system. Additionally, we investigate studies demonstrating an association between increased luminal protease activity and activation of protease receptors, ultimately resulting in increased intestinal permeability and exacerbation of colitis in animal models as well as in human IBD. Proteases are essential for the normal functioning of bacteria and in some cases can serve as virulence factors for pathogenic bacteria. Although not classified as traditional virulence factors, proteases originating from commensal enteric bacteria also have a potential association with intestinal inflammation via increased enteric permeability. Reports of increased protease activity in stools from IBD patients support a possible mechanism for a dysbiotic enteric microbiota in IBD. A better understanding of these pathways and characterization of the enteric bacteria involved, their proteases, and protease receptors may pave the way for new therapeutic approaches for these diseases.
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Fessele C, Lindhorst TK. Effect of Aminophenyl and Aminothiahexyl α-D-Glycosides of the Manno-, Gluco-, and Galacto-Series on Type 1 Fimbriae-Mediated Adhesion of Escherichia coli. BIOLOGY 2013; 2:1135-49. [PMID: 24833058 PMCID: PMC3960877 DOI: 10.3390/biology2031135] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 08/17/2013] [Accepted: 08/28/2013] [Indexed: 12/21/2022]
Abstract
Adhesion of bacteria to the glycosylated surface of their target cells is typically mediated by fimbrial lectins, exposed on the bacterial surface. Among the best-investigated and most important fimbriae are type 1 fimbriae, for which α-d-mannopyranoside-specificity has been described. This carbohydrate specificity is mediated by the type 1 fimbrial lectin FimH. In this account, we have employed four different set-ups to assay type 1 fimbriae-mediated bacterial adhesion, including tailor-made glycoarrays. The focus of our study was on testing FimH specificity with regard to the glycone part of a glycosidic ligand by testing a series of synthetic α-mannosides, as well as α-glucosides and α-galactosides. Unexpectedly, it was found that in solution all tested aminothiahexyl glycosides inhibit bacterial adhesion but that this effect is unspecific. Instead it is due to cytotoxicity of the respective glycosides at high mm concentrations.
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Affiliation(s)
- Claudia Fessele
- Otto Diels Institute of Organic Chemistry, Christiana Albertina University of Kiel, Otto-Hahn-Platz 3-4, 24098 Kiel, Germany.
| | - Thisbe K Lindhorst
- Otto Diels Institute of Organic Chemistry, Christiana Albertina University of Kiel, Otto-Hahn-Platz 3-4, 24098 Kiel, Germany.
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Chassaing B, Darfeuille-Michaud A. Adherent-invasive Escherichia coli Biofilm Formation Assays. Bio Protoc 2013. [DOI: 10.21769/bioprotoc.982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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