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Izquierdo-Vega JA, Castillo-Juarez RJ, Sánchez-Gutiérrez M, Ares MA, De La Cruz MA. A Mini-Review of Enteroaggregative Escherichia coli with a Specific Target on the Virulence Factors Controlled by the AggR Master Regulator. Pol J Microbiol 2023; 72:347-354. [PMID: 37875068 PMCID: PMC10725161 DOI: 10.33073/pjm-2023-037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 09/08/2023] [Indexed: 10/26/2023] Open
Abstract
Enteroaggregative Escherichia coli (EAEC) strains have been linked to several outbreaks of severe diarrhea around the world, and this bacterium is now commonly resistant to antibiotics. As part of the pathophysiology of EAEC, the characteristic pattern of adherence looks like stacked bricks on the intestinal epithelium. This phenotype depends on an aggregative adhesion plasmid (pAA), which codes for a regulatory protein named AggR. The AggR protein is a master regulator that transcriptionally actives the main virulence genes in this E. coli pathotype, such as those that encode the aggregative adhesion fimbriae, dispersin and its secretion apparatus, Aar regulatory protein, and type VI secretion system. Several reports have shown that AggR positively affects most EAEC virulence genes, functioning as a classic transcriptional activator in the promoter region of these genes, interacting with the RNA polymerase. This minireview article integrates the information about virulence determinants of EAEC controlled by the AggR regulator.
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Affiliation(s)
| | | | | | - Miguel A. Ares
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, México City, México
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, México
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Rodriguez-Valverde D, Giron JA, Hu Y, Nataro JP, Ruiz-Perez F, Santiago AE. Highly-conserved regulatory activity of the ANR family in the virulence of diarrheagenic bacteria through interaction with master and global regulators. Sci Rep 2023; 13:7024. [PMID: 37120613 PMCID: PMC10148876 DOI: 10.1038/s41598-023-33997-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 04/22/2023] [Indexed: 05/01/2023] Open
Abstract
ANR (AraC negative regulators) are a novel class of small regulatory proteins commonly found in enteric pathogens. Aar (AggR-activated regulator), the best-characterized member of the ANR family, regulates the master transcriptional regulator of virulence AggR and the global regulator HNS in enteroaggregative Escherichia coli (EAEC) by protein-protein interactions. On the other hand, Rnr (RegA-negative regulator) is an ANR homolog identified in attaching and effacing (AE) pathogens, including Citrobacter rodentium and enteropathogenic Escherichia coli (EPEC), sharing only 25% identity with Aar. We previously found that C. rodentium lacking Rnr exhibits prolonged shedding and increased gut colonization in mice compared to the parental strain. To gain mechanistic insights into this phenomenon, we characterized the regulatory role of Rnr in the virulence of prototype EPEC strain E2348/69 by genetic, biochemical, and human organoid-based approaches. Accordingly, RNA-seq analysis revealed more than 500 genes differentially regulated by Rnr, including the type-3 secretion system (T3SS). The abundance of EspA and EspB in whole cells and bacterial supernatants confirmed the negative regulatory activity of Rnr on T3SS effectors. We found that besides HNS and Ler, twenty-six other transcriptional regulators were also under Rnr control. Most importantly, the deletion of aar in EAEC or rnr in EPEC increases the adherence of these pathogens to human intestinal organoids. In contrast, the overexpression of ANR drastically reduces bacterial adherence and the formation of AE lesions in the intestine. Our study suggests a conserved regulatory mechanism and a central role of ANR in modulating intestinal colonization by these enteropathogens despite the fact that EAEC and EPEC evolved with utterly different virulence programs.
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Affiliation(s)
- Diana Rodriguez-Valverde
- Child Health Research Center, Department of Pediatrics, University of Virginia School of Medicine, 409 Lane Road, MR-4 Building, P.O. Box 801326, Charlottesville, VA, 22908, USA
| | - Jorge A Giron
- Centro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
- Translational Genomics Research Institute, 445 N. 5th St, Phoenix, AZ, 85004, USA
| | - Yang Hu
- CD Genomics, Shirley, NY, USA
| | - James P Nataro
- Child Health Research Center, Department of Pediatrics, University of Virginia School of Medicine, 409 Lane Road, MR-4 Building, P.O. Box 801326, Charlottesville, VA, 22908, USA
| | - Fernando Ruiz-Perez
- Child Health Research Center, Department of Pediatrics, University of Virginia School of Medicine, 409 Lane Road, MR-4 Building, P.O. Box 801326, Charlottesville, VA, 22908, USA
| | - Araceli E Santiago
- Child Health Research Center, Department of Pediatrics, University of Virginia School of Medicine, 409 Lane Road, MR-4 Building, P.O. Box 801326, Charlottesville, VA, 22908, USA.
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Site specific incidence rate of virulence related genes of enteroaggregative Escherichia coli and association with enteric inflammation and growth in children. Sci Rep 2021; 11:23178. [PMID: 34848801 PMCID: PMC8632913 DOI: 10.1038/s41598-021-02626-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 11/15/2021] [Indexed: 01/19/2023] Open
Abstract
There is a lack of information highlighting the possible association between strain carrying genes of enteroaggregative Escherichia coli (EAEC) and environmental enteric dysfunction (EED) and on linear growth during childhood. Strain carrying genes of EAEC from stool samples collected from 1705 children enrolled in the MAL-ED birth cohort were detected by TaqMan Array Cards. We measured site-specific incidence rate by using Poisson regression models, identified the risk factors and estimated the associations of strain carrying genes of EAEC with the composite EED score and linear growth at 24 months of age. Overall highest incidence rate (43.3%) was found among children having infection with the aggR gene, which was the greatest in Tanzania (56.7%). Low maternal education, lack of improved floor, and ownership of domestic cattle were found to be risk factors for EAEC infection. In the multivariate models, after adjusting the potential covariates, strain carrying genes of EAEC showed strong positive associations with the EED scores and with poor linear growth at 24 months of age. Our analyses may lay the cornerstone for a prospective epidemiologic investigation for a potential vaccine development aimed at reducing the burden of EAEC infections and combat childhood malnutrition.
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Abdelwahab R, Yasir M, Godfrey RE, Christie GS, Element SJ, Saville F, Hassan EA, Ahmed EH, Abu-Faddan NH, Daef EA, Busby SJW, Browning DF. Antimicrobial resistance and gene regulation in Enteroaggregative Escherichia coli from Egyptian children with diarrhoea: Similarities and differences. Virulence 2020; 12:57-74. [PMID: 33372849 PMCID: PMC7781526 DOI: 10.1080/21505594.2020.1859852] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Enteroaggregative Escherichia coli (EAEC) is a common diarrhoeagenic human pathogen, isolated from patients in both developing and industrialized countries, that is becoming increasingly resistant to many frontline antibiotics. In this study, we screened 50 E. coli strains from children presenting with diarrhea at the outpatients clinic of Assiut University Children’s Hospital, Egypt. We show that all of these isolates were resistant to multiple classes of antibiotics and identified two as being typical EAEC strains. Using whole genome sequencing, we determined that both isolates carried, amongst others, blaCTX-M and blaTEM antibiotic resistance genes, as well as many classical EAEC virulence determinants, including the transcriptional regulator, AggR. We demonstrate that the expression of these virulence determinants is dependent on AggR, including aar, which encodes for a repressor of AggR, Aar. Since biofilm formation is the hallmark of EAEC infection, we examined the effect of Aar overexpression on both biofilm formation and AggR-dependent gene expression. We show that whilst Aar has a minimal effect on AggR-dependent transcription it is able to completely disrupt biofilm formation, suggesting that Aar affects these two processes differently. Taken together, our results suggest a model for the induction of virulence gene expression in EAEC that may explain the ubiquity of EAEC in both sick and healthy individuals.
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Affiliation(s)
- Radwa Abdelwahab
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham , Birmingham, UK.,Faculty of Medicine, Assiut University , Assiut, Egypt
| | - Muhammad Yasir
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham , Birmingham, UK.,Quadram Institute Bioscience, Norwich Research Park , Norwich, UK
| | - Rita E Godfrey
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham , Birmingham, UK
| | - Gabrielle S Christie
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham , Birmingham, UK
| | - Sarah J Element
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham , Birmingham, UK
| | - Faye Saville
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham , Birmingham, UK
| | | | | | | | - Enas A Daef
- Faculty of Medicine, Assiut University , Assiut, Egypt
| | - Stephen J W Busby
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham , Birmingham, UK
| | - Douglas F Browning
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham , Birmingham, UK
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Brown JC. Involvement of promoter/enhancers in a feedback loop to regulate human gene expression. Heliyon 2020; 6:e04934. [PMID: 32995621 PMCID: PMC7501438 DOI: 10.1016/j.heliyon.2020.e04934] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 08/30/2020] [Accepted: 09/10/2020] [Indexed: 11/28/2022] Open
Abstract
The study described here was undertaken to extend the observation that some transcription factors can either stimulate or suppress gene expression depending on the local environment of their DNA binding site. It is suggested that if such transcription factors also had a mechanism to sense the expression level of the gene they control, then they could create a feedback loop able to keep expression of a gene within a limited range. The transcription factor would be activating if gene expression were determined to be too low and repressing if it were too high. To test the above idea, I have examined the effect of gene expression on the ability of the transcription factor binding areas, the promoter/enhancers, to stimulate or attenuate gene expression depending on the existing expression level of a gene. Studies were carried out with a population of 61 human genes expressed selectively in liver. A similar study was carried out with thyroid genes. The total length of all promoter/enhancers in each gene sequence was determined and compared in weakly and strongly expressed genes. The results showed that the level of expression was stimulated by promoter/enhancers in weakly expressed genes and antagonized in strongly expressed ones. The results are interpreted to indicate that promoter/enhancers act to keep expression of a gene within a defined range that is appropriate for the gene's function.
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Affiliation(s)
- Jay C Brown
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
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