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Freire de Melo F, Marques HS, Fellipe Bueno Lemos F, Silva Luz M, Rocha Pinheiro SL, de Carvalho LS, Souza CL, Oliveira MV. Role of nickel-regulated small RNA in modulation of Helicobacter pylori virulence factors. World J Clin Cases 2022; 10:11283-11291. [PMID: 36387830 PMCID: PMC9649571 DOI: 10.12998/wjcc.v10.i31.11283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/14/2022] [Accepted: 09/06/2022] [Indexed: 02/05/2023] Open
Abstract
Helicobacter pylori (H. pylori) is a Gram-negative bacterium that infects about half of the world's population. H. pylori infection prevails by several mechanisms of adaptation of the bacteria and by its virulence factors including the cytotoxin associated antigen A (CagA). CagA is an oncoprotein that is the protagonist of gastric carcinogenesis associated with prolonged H. pylori infection. In this sense, small regulatory RNAs (sRNAs) are important macromolecules capable of inhibiting and activating gene expression. This function allows sRNAs to act in adjusting to unstable environmental conditions and in responding to cellular stresses in bacterial infections. Recent discoveries have shown that nickel-regulated small RNA (NikS) is a post-transcriptional regulator of virulence properties of H. pylori, including the oncoprotein CagA. Notably, high concentrations of nickel cause the reduction of NikS expression and consequently this increases the levels of CagA. In addition, NikS expression appears to be lower in clinical isolates from patients with gastric cancer when compared to patients without. With that in mind, this minireview approaches, in an accessible way, the most important and current aspects about the role of NikS in the control of virulence factors of H. pylori and the potential clinical repercussions of this modulation.
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Affiliation(s)
- Fabrício Freire de Melo
- Institution Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Brazil
| | - Hanna Santos Marques
- Campus Vitória da Conquista, Universidade Estadual do Sudoeste da Bahia, Vitória da Conquista 45083-900, Brazil
| | - Fabian Fellipe Bueno Lemos
- Institution Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Brazil
| | - Marcel Silva Luz
- Institution Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Brazil
| | - Samuel Luca Rocha Pinheiro
- Institution Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Brazil
| | - Lorena Sousa de Carvalho
- Institution Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Brazil
| | - Cláudio Lima Souza
- Institution Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Brazil
| | - Márcio Vasconcelos Oliveira
- Institution Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Brazil
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2
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Mahendran G, Jayasinghe OT, Thavakumaran D, Arachchilage GM, Silva GN. Key players in regulatory RNA realm of bacteria. Biochem Biophys Rep 2022; 30:101276. [PMID: 35592614 PMCID: PMC9111926 DOI: 10.1016/j.bbrep.2022.101276] [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: 02/10/2022] [Revised: 04/30/2022] [Accepted: 05/04/2022] [Indexed: 11/30/2022] Open
Abstract
Precise regulation of gene expression is crucial for living cells to adapt for survival in diverse environmental conditions. Among the common cellular regulatory mechanisms, RNA-based regulators play a key role in all domains of life. Discovery of regulatory RNAs have made a paradigm shift in molecular biology as many regulatory functions of RNA have been identified beyond its canonical roles as messenger, ribosomal and transfer RNA. In the complex regulatory RNA network, riboswitches, small RNAs, and RNA thermometers can be identified as some of the key players. Herein, we review the discovery, mechanism, and potential therapeutic use of these classes of regulatory RNAs mainly found in bacteria. Being highly adaptive organisms that inhabit a broad range of ecological niches, bacteria have adopted tight and rapid-responding gene regulation mechanisms. This review aims to highlight how bacteria utilize versatile RNA structures and sequences to build a sophisticated gene regulation network. The three major classes of prokaryotic ncRNAs and their characterized mechanisms of operation in gene regulation. sRNAs emerging as major players in global gene regulatory networks. Riboswitch mediated gene control mechanisms through on/off switches in response to ligand binding. RNA thermo sensors for temperature-dependent gene expression. Therapeutic importance of ncRNAs and computational approaches involved in the discovery of ncRNAs.
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Affiliation(s)
- Gowthami Mahendran
- Department of Chemistry, University of Colombo, Colombo, Sri Lanka
- Department of Chemistry and Biochemistry, University of Notre Dame, IN, 46556, USA
| | - Oshadhi T. Jayasinghe
- Department of Chemistry, University of Colombo, Colombo, Sri Lanka
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, 16802, USA
| | - Dhanushika Thavakumaran
- Department of Chemistry, University of Colombo, Colombo, Sri Lanka
- Department of Chemistry and Biochemistry, University of Notre Dame, IN, 46556, USA
| | - Gayan Mirihana Arachchilage
- Howard Hughes Medical Institute, Yale University, New Haven, CT, 06520-8103, USA
- PTC Therapeutics Inc, South Plainfield, NJ, 07080, USA
| | - Gayathri N. Silva
- Department of Chemistry, University of Colombo, Colombo, Sri Lanka
- Corresponding author.
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3
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Svensson SL, Sharma CM. RNase III-mediated processing of a trans-acting bacterial sRNA and its cis-encoded antagonist. eLife 2021; 10:69064. [PMID: 34843430 PMCID: PMC8687705 DOI: 10.7554/elife.69064] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 11/28/2021] [Indexed: 12/27/2022] Open
Abstract
Bacterial small RNAs (sRNAs) are important post-transcriptional regulators in stress responses and virulence. They can be derived from an expanding list of genomic contexts, such as processing from parental transcripts by RNase E. The role of RNase III in sRNA biogenesis is less well understood despite its well-known roles in rRNA processing, RNA decay, and cleavage of sRNA-mRNA duplexes. Here, we show that RNase III processes a pair of cis-encoded sRNAs (CJnc190 and CJnc180) of the food-borne pathogen Campylobacter jejuni. While CJnc180 processing by RNase III requires CJnc190, RNase III processes CJnc190 independent of CJnc180 via cleavage of an intramolecular duplex. We also show that CJnc190 directly represses translation of the colonization factor PtmG by targeting a G-rich ribosome-binding site, and uncover that CJnc180 is a cis-acting antagonist of CJnc190, indirectly affecting ptmG regulation. Our study highlights a role for RNase III in sRNA biogenesis and adds cis-encoded RNAs to the expanding diversity of transcripts that can antagonize bacterial sRNAs.
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Affiliation(s)
- Sarah Lauren Svensson
- Department of Molecular Infection Biology II, Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Cynthia Mira Sharma
- Department of Molecular Infection Biology II, Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
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4
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Svensson SL, Sharma CM. Small RNAs that target G-rich sequences are generated by diverse biogenesis pathways in Epsilonproteobacteria. Mol Microbiol 2021; 117:215-233. [PMID: 34818434 DOI: 10.1111/mmi.14850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 11/22/2021] [Accepted: 11/22/2021] [Indexed: 11/30/2022]
Abstract
Bacterial small RNAs (sRNAs) are widespread post-transcriptional regulators controlling bacterial stress responses and virulence. Nevertheless, little is known about how they arise and evolve. Homologues can be difficult to identify beyond the strain level using sequence-based approaches, and similar functionalities can arise by convergent evolution. Here, we found that the virulence-associated CJnc190 sRNA of the foodborne pathogen Campylobacter jejuni resembles the RepG sRNA from the gastric pathogen Helicobacter pylori. However, while both sRNAs bind G-rich sites in their target mRNAs using a C/U-rich loop, they largely differ in their biogenesis. RepG is transcribed from a stand-alone gene and does not require processing, whereas CJnc190 is transcribed from two promoters as precursors that are processed by RNase III and also has a cis-encoded antagonist, CJnc180. By comparing CJnc190 homologues in diverse Campylobacter species, we show that RNase III-dependent processing of CJnc190 appears to be a conserved feature even outside of C. jejuni. We also demonstrate the CJnc180 antisense partner is expressed in C. coli, yet here might be derived from the 3'UTR of the upstream flagella-related gene. Our analysis of G-tract targeting sRNAs in Epsilonproteobacteria demonstrates that similar sRNAs can have markedly different biogenesis pathways.
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Affiliation(s)
- Sarah L Svensson
- Department of Molecular Infection Biology II, Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Bavaria, 97080, Germany
| | - Cynthia M Sharma
- Department of Molecular Infection Biology II, Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Bavaria, 97080, Germany
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5
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Tejada-Arranz A, De Reuse H. Riboregulation in the Major Gastric Pathogen Helicobacter pylori. Front Microbiol 2021; 12:712804. [PMID: 34335549 PMCID: PMC8322730 DOI: 10.3389/fmicb.2021.712804] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/23/2021] [Indexed: 02/05/2023] Open
Abstract
Helicobacter pylori is a Gram-negative bacterial pathogen that colonizes the stomach of about half of the human population worldwide. Infection by H. pylori is generally acquired during childhood and this bacterium rapidly establishes a persistent colonization. H. pylori causes chronic gastritis that, in some cases, progresses into peptic ulcer disease or adenocarcinoma that is responsible for about 800,000 deaths in the world every year. H. pylori has evolved efficient adaptive strategies to colonize the stomach, a particularly hostile acidic environment. Few transcriptional regulators are encoded by the small H. pylori genome and post-transcriptional regulation has been proposed as a major level of control of gene expression in this pathogen. The transcriptome and transcription start sites (TSSs) of H. pylori strain 26695 have been defined at the genome level. This revealed the existence of a total of 1,907 TSSs among which more than 900 TSSs for non-coding RNAs (ncRNAs) including 60 validated small RNAs (sRNAs) and abundant anti-sense RNAs, few of which have been experimentally validated. An RNA degradosome was shown to play a central role in the control of mRNA and antisense RNA decay in H. pylori. Riboregulation, genetic regulation by RNA, has also been revealed and depends both on antisense RNAs and small RNAs. Known examples will be presented in this review. Antisense RNA regulation was reported for some virulence factors and for several type I toxin antitoxin systems, one of which controls the morphological transition of H. pylori spiral shape to round coccoids. Interestingly, the few documented cases of small RNA-based regulation suggest that their mechanisms do not follow the same rules that were well established in the model organism Escherichia coli. First, the genome of H. pylori encodes none of the two well-described RNA chaperones, Hfq and ProQ that are important for riboregulation in several organisms. Second, some of the reported small RNAs target, through "rheostat"-like mechanisms, repeat-rich stretches in the 5'-untranslated region of genes encoding important virulence factors. In conclusion, there are still many unanswered questions about the extent and underlying mechanisms of riboregulation in H. pylori but recent publications highlighted original mechanisms making this important pathogen an interesting study model.
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Affiliation(s)
- Alejandro Tejada-Arranz
- Unité Pathogenèse de Helicobacter, CNRS UMR 2001, Département de Microbiologie, Institut Pasteur, Paris, France
- Université de Paris, Sorbonne Paris Cité, Paris, France
| | - Hilde De Reuse
- Unité Pathogenèse de Helicobacter, CNRS UMR 2001, Département de Microbiologie, Institut Pasteur, Paris, France
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Tejada-Arranz A, Matos RG, Quentin Y, Bouilloux-Lafont M, Galtier E, Briolat V, Kornobis E, Douché T, Matondo M, Arraiano CM, Raynal B, De Reuse H. RNase R is associated in a functional complex with the RhpA DEAD-box RNA helicase in Helicobacter pylori. Nucleic Acids Res 2021; 49:5249-5264. [PMID: 33893809 PMCID: PMC8136821 DOI: 10.1093/nar/gkab283] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/06/2021] [Accepted: 04/09/2021] [Indexed: 02/06/2023] Open
Abstract
Ribonucleases are central players in post-transcriptional regulation, a major level of gene expression regulation in all cells. Here, we characterized the 3'-5' exoribonuclease RNase R from the bacterial pathogen Helicobacter pylori. The 'prototypical' Escherichia coli RNase R displays both exoribonuclease and helicase activities, but whether this latter RNA unwinding function is a general feature of bacterial RNase R had not been addressed. We observed that H. pylori HpRNase R protein does not carry the domains responsible for helicase activity and accordingly the purified protein is unable to degrade in vitro RNA molecules with secondary structures. The lack of RNase R helicase domains is widespread among the Campylobacterota, which include Helicobacter and Campylobacter genera, and this loss occurred gradually during their evolution. An in vivo interaction between HpRNase R and RhpA, the sole DEAD-box RNA helicase of H. pylori was discovered. Purified RhpA facilitates the degradation of double stranded RNA by HpRNase R, showing that this complex is functional. HpRNase R has a minor role in 5S rRNA maturation and few targets in H. pylori, all included in the RhpA regulon. We concluded that during evolution, HpRNase R has co-opted the RhpA helicase to compensate for its lack of helicase activity.
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Affiliation(s)
- Alejandro Tejada-Arranz
- Unité Pathogenèse de Helicobacter, CNRS UMR 2001, Département de Microbiologie, Institut Pasteur, 75724 Paris Cedex 15, France
- Université de Paris, Sorbonne Paris Cité, 75006 Paris, France
| | - Rute G Matos
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, 2780-157 Oeiras, Portugal
| | - Yves Quentin
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, UMR CNRS 5100, 31062 TOULOUSE Cedex 9, France
| | - Maxime Bouilloux-Lafont
- Unité Pathogenèse de Helicobacter, CNRS UMR 2001, Département de Microbiologie, Institut Pasteur, 75724 Paris Cedex 15, France
| | - Eloïse Galtier
- Unité Pathogenèse de Helicobacter, CNRS UMR 2001, Département de Microbiologie, Institut Pasteur, 75724 Paris Cedex 15, France
| | - Valérie Briolat
- Biomics, C2RT, Institut Pasteur, 75724 Paris Cedex 15, France
| | - Etienne Kornobis
- Biomics, C2RT, Institut Pasteur, 75724 Paris Cedex 15, France
- Hub Bioinformatique et Biostatistique, Département de Biologie Computationelle, USR CNRS 3756, Institut Pasteur, 75724 Paris Cedex 15, France
| | - Thibaut Douché
- Plateforme Protéomique, Unité de Spectrométrie de Masse pour la Biologie, C2RT, USR CNRS 2000, Institut Pasteur, 75724 Paris Cedex 15, France
| | - Mariette Matondo
- Plateforme Protéomique, Unité de Spectrométrie de Masse pour la Biologie, C2RT, USR CNRS 2000, Institut Pasteur, 75724 Paris Cedex 15, France
| | - Cecilia M Arraiano
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, 2780-157 Oeiras, Portugal
| | - Bertrand Raynal
- Plateforme de biophysique moléculaire, UMR CNRS 3528, Département de Biologie structurale et chimie, Institut Pasteur, 75724 Paris Cedex 15, France
| | - Hilde De Reuse
- Unité Pathogenèse de Helicobacter, CNRS UMR 2001, Département de Microbiologie, Institut Pasteur, 75724 Paris Cedex 15, France
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7
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Wang C, Hu Y, Yang H, Wang S, Zhou B, Bao Y, Huang Y, Luo Q, Yang C, Xie X, Yang S. Function of Non-coding RNA in Helicobacter pylori-Infected Gastric Cancer. Front Mol Biosci 2021; 8:649105. [PMID: 34046430 PMCID: PMC8144459 DOI: 10.3389/fmolb.2021.649105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Accepted: 03/10/2021] [Indexed: 12/12/2022] Open
Abstract
Gastric cancer is a common malignant tumor of the digestive system. Its occurrence and development are the result of a combination of genetic, environmental, and microbial factors. Helicobacter pylori infection is a chronic infection that is closely related to the occurrence of gastric tumorigenesis. Non-coding RNA has been demonstrated to play a very important role in the organism, exerting a prominent role in the carcinogenesis, proliferation, apoptosis, invasion, metastasis, and chemoresistance of tumor progression. H. pylori infection affects the expression of non-coding RNA at multiple levels such as genetic polymorphisms and signaling pathways, thereby promoting or inhibiting tumor progression or chemoresistance. This paper mainly introduces the relationship between H. pylori-infected gastric cancer and non-coding RNA, providing a new perspective for gastric cancer treatment.
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Affiliation(s)
- Chao Wang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Yiyang Hu
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Huan Yang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Sumin Wang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Bo Zhou
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Yulu Bao
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Yu Huang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Qiang Luo
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Chuan Yang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Xia Xie
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Shiming Yang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
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A bacterial small RNA regulates the adaptation of Helicobacter pylori to the host environment. Nat Commun 2021; 12:2085. [PMID: 33837194 PMCID: PMC8035401 DOI: 10.1038/s41467-021-22317-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Accepted: 03/10/2021] [Indexed: 12/15/2022] Open
Abstract
Long-term infection of the stomach with Helicobacter pylori can cause gastric cancer. However, the mechanisms by which the bacteria adapt to the stomach environment are poorly understood. Here, we show that a small non-coding RNA of H. pylori (HPnc4160, also known as IsoB or NikS) regulates the pathogen’s adaptation to the host environment as well as bacterial oncoprotein production. In a rodent model of H. pylori infection, the genomes of bacteria isolated from the stomach possess an increased number of T-repeats upstream of the HPnc4160-coding region, and this leads to reduced HPnc4160 expression. We use RNA-seq and iTRAQ analyses to identify eight targets of HPnc4160, including genes encoding outer membrane proteins and oncoprotein CagA. Mutant strains with HPnc4160 deficiency display increased colonization ability of the mouse stomach, in comparison with the wild-type strain. Furthermore, HPnc4160 expression is lower in clinical isolates from gastric cancer patients than in isolates derived from non-cancer patients, while the expression of HPnc4160’s targets is higher in the isolates from gastric cancer patients. Therefore, the small RNA HPnc4160 regulates H. pylori adaptation to the host environment and, potentially, gastric carcinogenesis. Long-term infection of the stomach with Helicobacter pylori can cause gastric cancer. Here, Kinoshita-Daitoku et al. show that a small non-coding RNA of H. pylori regulates bacterial adaptation to the stomach environment and bacterial oncoprotein production.
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Desgranges E, Caldelari I, Marzi S, Lalaouna D. Navigation through the twists and turns of RNA sequencing technologies: Application to bacterial regulatory RNAs. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194506. [PMID: 32068131 DOI: 10.1016/j.bbagrm.2020.194506] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/11/2020] [Accepted: 02/13/2020] [Indexed: 12/20/2022]
Abstract
Discovered in the 1980s, small regulatory RNAs (sRNAs) are now considered key actors in virtually all aspects of bacterial physiology and virulence. Together with transcriptional and translational regulatory proteins, they integrate and often are hubs of complex regulatory networks, responsible for bacterial response/adaptation to various perceived stimuli. The recent development of powerful RNA sequencing technologies has facilitated the identification and characterization of sRNAs (length, structure and expression conditions) and their RNA targets in several bacteria. Nevertheless, it could be very difficult for non-experts to understand the advantages and drawbacks related to each offered option and, consequently, to make an informed choice. Therefore, the main goal of this review is to provide a guide to navigate through the twists and turns of high-throughput RNA sequencing technologies, with a specific focus on those applied to the study of sRNAs. This article is part of a Special Issue entitled: RNA and gene control in bacteria edited by Dr. M. Guillier and F. Repoila.
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Affiliation(s)
- Emma Desgranges
- Université de Strasbourg, CNRS, ARN UPR 9002, F-67000 Strasbourg, France
| | - Isabelle Caldelari
- Université de Strasbourg, CNRS, ARN UPR 9002, F-67000 Strasbourg, France
| | - Stefano Marzi
- Université de Strasbourg, CNRS, ARN UPR 9002, F-67000 Strasbourg, France
| | - David Lalaouna
- Université de Strasbourg, CNRS, ARN UPR 9002, F-67000 Strasbourg, France.
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Nie X, Remes B, Klug G. Multiple Sense and Antisense Promoters Contribute to the Regulated Expression of the isc-suf Operon for Iron-Sulfur Cluster Assembly in Rhodobacter. Microorganisms 2019; 7:microorganisms7120671. [PMID: 31835540 PMCID: PMC6956336 DOI: 10.3390/microorganisms7120671] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 12/02/2019] [Accepted: 12/04/2019] [Indexed: 11/16/2022] Open
Abstract
A multitude of biological functions relies on iron-sulfur clusters. The formation of photosynthetic complexes goes along with an additional demand for iron-sulfur clusters for bacteriochlorophyll synthesis and photosynthetic electron transport. However, photooxidative stress leads to the destruction of iron-sulfur clusters, and the released iron promotes the formation of further reactive oxygen species. A balanced regulation of iron-sulfur cluster synthesis is required to guarantee the supply of this cofactor, on the one hand, but also to limit stress, on the other hand. The phototrophic alpha-proteobacterium Rhodobacter sphaeroides harbors a large operon for iron-sulfur cluster assembly comprising the iscRS and suf genes. IscR (iron-sulfur cluster regulator) is an iron-dependent regulator of isc-suf genes and other genes with a role in iron metabolism. We applied reporter gene fusions to identify promoters of the isc-suf operon and studied their activity alone or in combination under different conditions. Gel-retardation assays showed the binding of regulatory proteins to individual promoters. Our results demonstrated that several promoters in a sense and antisense direction influenced isc-suf expression and the binding of the IscR, Irr, and OxyR regulatory proteins to individual promoters. These findings demonstrated a complex regulatory network of several promoters and regulatory proteins that helped to adjust iron-sulfur cluster assembly to changing conditions in Rhodobacter sphaeroides.
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11
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Chakravarty S, Massé E. RNA-Dependent Regulation of Virulence in Pathogenic Bacteria. Front Cell Infect Microbiol 2019; 9:337. [PMID: 31649894 PMCID: PMC6794450 DOI: 10.3389/fcimb.2019.00337] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 09/18/2019] [Indexed: 12/19/2022] Open
Abstract
During infection, bacterial pathogens successfully sense, respond and adapt to a myriad of harsh environments presented by the mammalian host. This exquisite level of adaptation requires a robust modulation of their physiological and metabolic features. Additionally, virulence determinants, which include host invasion, colonization and survival despite the host's immune responses and antimicrobial therapy, must be optimally orchestrated by the pathogen at all times during infection. This can only be achieved by tight coordination of gene expression. A large body of evidence implicate the prolific roles played by bacterial regulatory RNAs in mediating gene expression both at the transcriptional and post-transcriptional levels. This review describes mechanistic and regulatory aspects of bacterial regulatory RNAs and highlights how these molecules increase virulence efficiency in human pathogens. As illustrative examples, Staphylococcus aureus, Listeria monocytogenes, the uropathogenic strain of Escherichia coli, Helicobacter pylori, and Pseudomonas aeruginosa have been selected.
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Affiliation(s)
- Shubham Chakravarty
- RNA Group, Department of Biochemistry, Faculty of Medicine and Health Sciences, CRCHUS, University of Sherbrooke, Sherbrooke, QC, Canada
| | - Eric Massé
- RNA Group, Department of Biochemistry, Faculty of Medicine and Health Sciences, CRCHUS, University of Sherbrooke, Sherbrooke, QC, Canada
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12
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The Sole DEAD-Box RNA Helicase of the Gastric Pathogen Helicobacter pylori Is Essential for Colonization. mBio 2018; 9:mBio.02071-17. [PMID: 29588407 PMCID: PMC5874925 DOI: 10.1128/mbio.02071-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Present in every kingdom of life, generally in multiple copies, DEAD-box RNA helicases are specialized enzymes that unwind RNA secondary structures. They play major roles in mRNA decay, ribosome biogenesis, and adaptation to cold temperatures. Most bacteria have multiple DEAD-box helicases that present both specialized and partially redundant functions. By using phylogenomics, we revealed that the Helicobacter genus, including the major gastric pathogen H. pylori, is among the exceptions, as it encodes a sole DEAD-box RNA helicase. In H. pylori, this helicase, designated RhpA, forms a minimal RNA degradosome together with the essential RNase, RNase J, a major player in the control of RNA decay. Here, we used H. pylori as a model organism with a sole DEAD-box helicase and investigated the role of this helicase in H. pylori physiology, ribosome assembly, and during in vivo colonization. Our data showed that RhpA is dispensable for growth at 37°C but crucial at 33°C, suggesting an essential role of the helicase in cold adaptation. Moreover, we found that a ΔrhpA mutant was impaired in motility and deficient in colonization of the mouse model. RhpA is involved in the maturation of 16S rRNA at 37°C and is associated with translating ribosomes. At 33°C, RhpA is, in addition, recruited to individual ribosomal subunits. Finally, via its role in the RNA degradosome, RhpA directs the regulation of the expression of its partner, RNase J. RhpA is thus a multifunctional enzyme that, in H. pylori, plays a central role in gene regulation and in the control of virulence.IMPORTANCE We present the results of our study on the role of RhpA, the sole DEAD-box RNA helicase encoded by the major gastric pathogen Helicobacter pylori We observed that all the Helicobacter species possess such a sole helicase, in contrast to most free-living bacteria. RhpA is not essential for growth of H. pylori under normal conditions. However, deletion of rhpA leads to a motility defect and to total inhibition of the ability of H. pylori to colonize a mouse model. We also demonstrated that this helicase encompasses most of the functions of its specialized orthologs described so far. We found that RhpA is a key element of the bacterial adaptation to colder temperatures and plays a minor role in ribosome biogenesis. Finally, RhpA regulates transcription of the rnj gene encoding RNase J, its essential partner in the minimal H. pylori RNA degradosome, and thus plays a crucial role in the control of RNA decay.
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Arnion H, Korkut DN, Masachis Gelo S, Chabas S, Reignier J, Iost I, Darfeuille F. Mechanistic insights into type I toxin antitoxin systems in Helicobacter pylori: the importance of mRNA folding in controlling toxin expression. Nucleic Acids Res 2017; 45:4782-4795. [PMID: 28077560 PMCID: PMC5416894 DOI: 10.1093/nar/gkw1343] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 12/22/2016] [Indexed: 12/16/2022] Open
Abstract
Type I toxin-antitoxin (TA) systems have been identified in a wide range of bacterial genomes. Here, we report the characterization of a new type I TA system present on the chromosome of the major human gastric pathogen, Helicobacter pylori. We show that the aapA1 gene encodes a 30 amino acid peptide whose artificial expression in H. pylori induces cell death. The synthesis of this toxin is prevented by the transcription of an antitoxin RNA, named IsoA1, expressed on the opposite strand of the toxin gene. We further reveal additional layers of post-transcriptional regulation that control toxin expression: (i) transcription of the aapA1 gene generates a full-length transcript whose folding impedes translation (ii) a 3΄ end processing of this message generates a shorter transcript that, after a structural rearrangement, becomes translatable (iii) but this rearrangement also leads to the formation of two stem-loop structures allowing formation of an extended duplex with IsoA1 via kissing-loop interactions. This interaction ensures both the translation inhibition of the AapA1 active message and its rapid degradation by RNase III, thus preventing toxin synthesis under normal growth conditions. Finally, a search for homologous mRNA structures identifies similar TA systems in a large number of Helicobacter and Campylobacter genomes.
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Affiliation(s)
- Hélène Arnion
- INSERM U1212, CNRS UMR5320, Univ. Bordeaux, ARNA Laboratory, 146 rue Léo Saignat, F-33076 Bordeaux, France
| | - Dursun Nizam Korkut
- INSERM U1212, CNRS UMR5320, Univ. Bordeaux, ARNA Laboratory, 146 rue Léo Saignat, F-33076 Bordeaux, France
| | - Sara Masachis Gelo
- INSERM U1212, CNRS UMR5320, Univ. Bordeaux, ARNA Laboratory, 146 rue Léo Saignat, F-33076 Bordeaux, France
| | - Sandrine Chabas
- INSERM U1212, CNRS UMR5320, Univ. Bordeaux, ARNA Laboratory, 146 rue Léo Saignat, F-33076 Bordeaux, France
| | - Jérémy Reignier
- INSERM U1212, CNRS UMR5320, Univ. Bordeaux, ARNA Laboratory, 146 rue Léo Saignat, F-33076 Bordeaux, France
| | - Isabelle Iost
- INSERM U1212, CNRS UMR5320, Univ. Bordeaux, ARNA Laboratory, 146 rue Léo Saignat, F-33076 Bordeaux, France
| | - Fabien Darfeuille
- INSERM U1212, CNRS UMR5320, Univ. Bordeaux, ARNA Laboratory, 146 rue Léo Saignat, F-33076 Bordeaux, France
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14
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Abstract
Bacterial pathogens must endure or adapt to different environments and stresses during transmission and infection. Posttranscriptional gene expression control by regulatory RNAs, such as small RNAs and riboswitches, is now considered central to adaptation in many bacteria, including pathogens. The study of RNA-based regulation (riboregulation) in pathogenic species has provided novel insight into how these bacteria regulate virulence gene expression. It has also uncovered diverse mechanisms by which bacterial small RNAs, in general, globally control gene expression. Riboregulators as well as their targets may also prove to be alternative targets or provide new strategies for antimicrobials. In this article, we present an overview of the general mechanisms that bacteria use to regulate with RNA, focusing on examples from pathogens. In addition, we also briefly review how deep sequencing approaches have aided in opening new perspectives in small RNA identification and the study of their functions. Finally, we discuss examples of riboregulators in two model pathogens that control virulence factor expression or survival-associated phenotypes, such as stress tolerance, biofilm formation, or cell-cell communication, to illustrate how riboregulation factors into regulatory networks in bacterial pathogens.
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Viladomiu M, Bassaganya-Riera J, Tubau-Juni N, Kronsteiner B, Leber A, Philipson CW, Zoccoli-Rodriguez V, Hontecillas R. Cooperation of Gastric Mononuclear Phagocytes with Helicobacter pylori during Colonization. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2017; 198:3195-3204. [PMID: 28264969 PMCID: PMC5380565 DOI: 10.4049/jimmunol.1601902] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 02/08/2017] [Indexed: 12/17/2022]
Abstract
Helicobacter pylori, the dominant member of the human gastric microbiota, elicits immunoregulatory responses implicated in protective versus pathological outcomes. To evaluate the role of macrophages during infection, we employed a system with a shifted proinflammatory macrophage phenotype by deleting PPARγ in myeloid cells and found a 5- to 10-fold decrease in gastric bacterial loads. Higher levels of colonization in wild-type mice were associated with increased presence of mononuclear phagocytes and in particular with the accumulation of CD11b+F4/80hiCD64+CX3CR1+ macrophages in the gastric lamina propria. Depletion of phagocytic cells by clodronate liposomes in wild-type mice resulted in a reduction of gastric H. pylori colonization compared with nontreated mice. PPARγ-deficient and macrophage-depleted mice presented decreased IL-10-mediated myeloid and T cell regulatory responses soon after infection. IL-10 neutralization during H. pylori infection led to increased IL-17-mediated responses and increased neutrophil accumulation at the gastric mucosa. In conclusion, we report the induction of IL-10-driven regulatory responses mediated by CD11b+F4/80hiCD64+CX3CR1+ mononuclear phagocytes that contribute to maintaining high levels of H. pylori loads in the stomach by modulating effector T cell responses at the gastric mucosa.
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Affiliation(s)
- Monica Viladomiu
- Nutritional Immunology and Molecular Medicine Laboratory, Biocomplexity Institute of Virginia Tech, Blacksburg, VA 24061
| | - Josep Bassaganya-Riera
- Nutritional Immunology and Molecular Medicine Laboratory, Biocomplexity Institute of Virginia Tech, Blacksburg, VA 24061
| | - Nuria Tubau-Juni
- Nutritional Immunology and Molecular Medicine Laboratory, Biocomplexity Institute of Virginia Tech, Blacksburg, VA 24061
| | - Barbara Kronsteiner
- Nutritional Immunology and Molecular Medicine Laboratory, Biocomplexity Institute of Virginia Tech, Blacksburg, VA 24061
| | - Andrew Leber
- Nutritional Immunology and Molecular Medicine Laboratory, Biocomplexity Institute of Virginia Tech, Blacksburg, VA 24061
| | - Casandra W Philipson
- Nutritional Immunology and Molecular Medicine Laboratory, Biocomplexity Institute of Virginia Tech, Blacksburg, VA 24061
| | - Victoria Zoccoli-Rodriguez
- Nutritional Immunology and Molecular Medicine Laboratory, Biocomplexity Institute of Virginia Tech, Blacksburg, VA 24061
| | - Raquel Hontecillas
- Nutritional Immunology and Molecular Medicine Laboratory, Biocomplexity Institute of Virginia Tech, Blacksburg, VA 24061
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Redko Y, Galtier E, Arnion H, Darfeuille F, Sismeiro O, Coppée JY, Médigue C, Weiman M, Cruveiller S, De Reuse H. RNase J depletion leads to massive changes in mRNA abundance in Helicobacter pylori. RNA Biol 2016; 13:243-53. [PMID: 26726773 DOI: 10.1080/15476286.2015.1132141] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Degradation of RNA as an intermediate message between genes and corresponding proteins is important for rapid attenuation of gene expression and maintenance of cellular homeostasis. This process is controlled by ribonucleases that have different target specificities. In the bacterial pathogen Helicobacter pylori, an exo- and endoribonuclease RNase J is essential for growth. To explore the role of RNase J in H. pylori, we identified its putative targets at a global scale using next generation RNA sequencing. We found that strong depletion for RNase J led to a massive increase in the steady-state levels of non-rRNAs. mRNAs and RNAs antisense to open reading frames were most affected with over 80% increased more than 2-fold. Non-coding RNAs expressed in the intergenic regions were much less affected by RNase J depletion. Northern blotting of selected messenger and non-coding RNAs validated these results. Globally, our data suggest that RNase J of H. pylori is a major RNase involved in degradation of most cellular RNAs.
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Affiliation(s)
- Yulia Redko
- a Institut Pasteur, Département de Microbiologie, Unité Pathogenèse de Helicobacter , ERL CNRS 3526
| | - Eloïse Galtier
- a Institut Pasteur, Département de Microbiologie, Unité Pathogenèse de Helicobacter , ERL CNRS 3526
| | - Hélène Arnion
- b INSERM U869, University of Bordeaux , 146 rue Léo Saignat, 33076 Bordeaux , France
| | - Fabien Darfeuille
- b INSERM U869, University of Bordeaux , 146 rue Léo Saignat, 33076 Bordeaux , France
| | - Odile Sismeiro
- c Institut Pasteur, Plate-Forme 2 - Transcriptome et Epigénome
| | | | - Claudine Médigue
- d CNRS-UMR 8030 and Commissariat à l'Energie Atomique et aux Energies Alternatives CEA/DSV/IG/Genoscope LABGeM , Evry , France
| | - Marion Weiman
- d CNRS-UMR 8030 and Commissariat à l'Energie Atomique et aux Energies Alternatives CEA/DSV/IG/Genoscope LABGeM , Evry , France
| | - Stéphane Cruveiller
- d CNRS-UMR 8030 and Commissariat à l'Energie Atomique et aux Energies Alternatives CEA/DSV/IG/Genoscope LABGeM , Evry , France
| | - Hilde De Reuse
- a Institut Pasteur, Département de Microbiologie, Unité Pathogenèse de Helicobacter , ERL CNRS 3526
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Vannini A, Roncarati D, Danielli A. The cag-pathogenicity island encoded CncR1 sRNA oppositely modulates Helicobacter pylori motility and adhesion to host cells. Cell Mol Life Sci 2016; 73:3151-68. [PMID: 26863876 PMCID: PMC11108448 DOI: 10.1007/s00018-016-2151-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 01/13/2016] [Accepted: 01/28/2016] [Indexed: 02/08/2023]
Abstract
Small regulatory RNAs (sRNAs) are emerging as key post-transcriptional regulators in many bacteria. In the human pathobiont Helicobacter pylori a plethora of trans- and cis-encoded sRNAs have been pinpointed by a global transcriptome study. However, only two have been studied in depth at the functional level. Here we report the characterization of CncR1, an abundant and conserved sRNA encoded by the virulence-associated cag pathogenicity island (cag-PAI) of H. pylori. Growth-phase dependent transcription of CncR1 is directed by the PcagP promoter, which resulted to be a target of the essential transcriptional regulator HsrA (HP1043). We demonstrate that the 213 nt transcript arising from this promoter ends at an intrinsic terminator, few bases upstream of the annotated cagP open reading frame, establishing CncR1 as the predominant gene product encoded by the cagP (cag15) locus. Interestingly, the deletion of the locus resulted in the deregulation en masse of σ(54)-dependent genes, linking CncR1 to flagellar functions. Accordingly, the enhanced motility recorded for cncR1 deletion mutants was complemented by ectopic reintroduction of the allele in trans. In silico prediction identified fliK, encoding a flagellar checkpoint protein, as likely regulatory target of CncR1. The interaction of CncR1 with the fliK mRNA was thus further investigated in vitro, demonstrating the formation of strand-specific interactions between the two RNA molecules. Accordingly, the full-length translational fusions of fliK with a lux reporter gene were induced in a cncR1 deletion mutant in vivo. These data suggest the involvement of CncR1 in the post-transcriptional modulation of H. pylori motility functions through down-regulation of a critical flagellar checkpoint factor. Concurrently, the cncR1 mutant revealed a decrease of transcript levels for several H. pylori adhesins, resulting in a phenotypically significant impairment of bacterial adhesion to a host gastric cell line. The data presented support a model in which the cag-PAI encoded CncR1 sRNA is able to oppositely modulate bacterial motility and adhesion to host cells.
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Affiliation(s)
- Andrea Vannini
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Davide Roncarati
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Alberto Danielli
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, via Selmi 3, 40126, Bologna, Italy.
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18
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Leber A, Abedi V, Hontecillas R, Viladomiu M, Hoops S, Ciupe S, Caughman J, Andrew T, Bassaganya-Riera J. Bistability analyses of CD4+ T follicular helper and regulatory cells during Helicobacter pylori infection. J Theor Biol 2016; 398:74-84. [PMID: 26947272 DOI: 10.1016/j.jtbi.2016.02.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 02/24/2016] [Accepted: 02/26/2016] [Indexed: 12/22/2022]
Abstract
T follicular helper (Tfh) cells are a highly plastic subset of CD4+ T cells specialized in providing B cell help and promoting inflammatory and effector responses during infectious and immune-mediate diseases. Helicobacter pylori is the dominant member of the gastric microbiota and exerts both beneficial and harmful effects on the host. Chronic inflammation in the context of H. pylori has been linked to an upregulation in T helper (Th)1 and Th17 CD4+ T cell phenotypes, controlled in part by the cytokine, interleukin-21. This study investigates the differentiation and regulation of Tfh cells, major producers of IL-21, in the immune response to H. pylori challenge. To better understand the conditions influencing the promotion and inhibition of a chronically elevated Tfh population, we used top-down and bottom-up approaches to develop computational models of Tfh and T follicular regulatory (Tfr) cell differentiation. Stability analysis was used to characterize the presence of two bi-stable steady states in the calibrated Tfh/Tfr models. Stochastic simulation was used to illustrate the ability of the parameter set to dictate two distinct behavioral patterns. Furthermore, sensitivity analysis helped identify the importance of various parameters on the establishment of Tfh and Tfr cell populations. The core network model was expanded into a more comprehensive and predictive model by including cytokine production and signaling pathways. From the expanded network, the interaction between TGFB-Induced Factor Homeobox 1 (Tgif1) and the retinoid X receptor (RXR) was displayed to exert control over the determination of the Tfh response. Model simulations predict that Tgif1 and RXR respectively induce and curtail Tfh responses. This computational hypothesis was validated experimentally by assaying Tgif1, RXR and Tfh in stomachs of mice infected with H. pylori.
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Affiliation(s)
- Andrew Leber
- Nutritional Immunology and Molecular Medicine Laboratory, Biocomplexity Institute of Virginia Tech, Blacksburg, VA, USA; Center for Modeling Immunity to Enteric Pathogens, Biocomplexity Institute of Virginia Tech, Blacksburg, VA, USA
| | - Vida Abedi
- Nutritional Immunology and Molecular Medicine Laboratory, Biocomplexity Institute of Virginia Tech, Blacksburg, VA, USA; Center for Modeling Immunity to Enteric Pathogens, Biocomplexity Institute of Virginia Tech, Blacksburg, VA, USA
| | - Raquel Hontecillas
- Nutritional Immunology and Molecular Medicine Laboratory, Biocomplexity Institute of Virginia Tech, Blacksburg, VA, USA; Center for Modeling Immunity to Enteric Pathogens, Biocomplexity Institute of Virginia Tech, Blacksburg, VA, USA
| | - Monica Viladomiu
- Nutritional Immunology and Molecular Medicine Laboratory, Biocomplexity Institute of Virginia Tech, Blacksburg, VA, USA; Center for Modeling Immunity to Enteric Pathogens, Biocomplexity Institute of Virginia Tech, Blacksburg, VA, USA
| | - Stefan Hoops
- Nutritional Immunology and Molecular Medicine Laboratory, Biocomplexity Institute of Virginia Tech, Blacksburg, VA, USA; Center for Modeling Immunity to Enteric Pathogens, Biocomplexity Institute of Virginia Tech, Blacksburg, VA, USA
| | - Stanca Ciupe
- Center for Modeling Immunity to Enteric Pathogens, Biocomplexity Institute of Virginia Tech, Blacksburg, VA, USA; Department of Mathematics, Virginia Tech, Blacksburg, VA, USA
| | - John Caughman
- Nutritional Immunology and Molecular Medicine Laboratory, Biocomplexity Institute of Virginia Tech, Blacksburg, VA, USA; Center for Modeling Immunity to Enteric Pathogens, Biocomplexity Institute of Virginia Tech, Blacksburg, VA, USA
| | - Tricity Andrew
- Nutritional Immunology and Molecular Medicine Laboratory, Biocomplexity Institute of Virginia Tech, Blacksburg, VA, USA; Center for Modeling Immunity to Enteric Pathogens, Biocomplexity Institute of Virginia Tech, Blacksburg, VA, USA
| | - Josep Bassaganya-Riera
- Nutritional Immunology and Molecular Medicine Laboratory, Biocomplexity Institute of Virginia Tech, Blacksburg, VA, USA; Center for Modeling Immunity to Enteric Pathogens, Biocomplexity Institute of Virginia Tech, Blacksburg, VA, USA.
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19
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Le MT, van Veldhuizen M, Porcelli I, Bongaerts RJ, Gaskin DJH, Pearson BM, van Vliet AHM. Conservation of σ28-Dependent Non-Coding RNA Paralogs and Predicted σ54-Dependent Targets in Thermophilic Campylobacter Species. PLoS One 2015; 10:e0141627. [PMID: 26512728 PMCID: PMC4626219 DOI: 10.1371/journal.pone.0141627] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/09/2015] [Indexed: 12/28/2022] Open
Abstract
Assembly of flagella requires strict hierarchical and temporal control via flagellar sigma and anti-sigma factors, regulatory proteins and the assembly complex itself, but to date non-coding RNAs (ncRNAs) have not been described to regulate genes directly involved in flagellar assembly. In this study we have investigated the possible role of two ncRNA paralogs (CjNC1, CjNC4) in flagellar assembly and gene regulation of the diarrhoeal pathogen Campylobacter jejuni. CjNC1 and CjNC4 are 37/44 nt identical and predicted to target the 5' untranslated region (5' UTR) of genes transcribed from the flagellar sigma factor σ54. Orthologs of the σ54-dependent 5' UTRs and ncRNAs are present in the genomes of other thermophilic Campylobacter species, and transcription of CjNC1 and CNC4 is dependent on the flagellar sigma factor σ28. Surprisingly, inactivation and overexpression of CjNC1 and CjNC4 did not affect growth, motility or flagella-associated phenotypes such as autoagglutination. However, CjNC1 and CjNC4 were able to mediate sequence-dependent, but Hfq-independent, partial repression of fluorescence of predicted target 5' UTRs in an Escherichia coli-based GFP reporter gene system. This hints towards a subtle role for the CjNC1 and CjNC4 ncRNAs in post-transcriptional gene regulation in thermophilic Campylobacter species, and suggests that the currently used phenotypic methodologies are insufficiently sensitive to detect such subtle phenotypes. The lack of a role of Hfq in the E. coli GFP-based system indicates that the CjNC1 and CjNC4 ncRNAs may mediate post-transcriptional gene regulation in ways that do not conform to the paradigms obtained from the Enterobacteriaceae.
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Affiliation(s)
- My Thanh Le
- Gut Health and Food Safety Programme, Institute of Food Research, Norwich Research Park, Norwich, United Kingdom
| | - Mart van Veldhuizen
- Gut Health and Food Safety Programme, Institute of Food Research, Norwich Research Park, Norwich, United Kingdom
| | - Ida Porcelli
- Gut Health and Food Safety Programme, Institute of Food Research, Norwich Research Park, Norwich, United Kingdom
| | - Roy J. Bongaerts
- Gut Health and Food Safety Programme, Institute of Food Research, Norwich Research Park, Norwich, United Kingdom
| | - Duncan J. H. Gaskin
- Gut Health and Food Safety Programme, Institute of Food Research, Norwich Research Park, Norwich, United Kingdom
| | - Bruce M. Pearson
- Gut Health and Food Safety Programme, Institute of Food Research, Norwich Research Park, Norwich, United Kingdom
| | - Arnoud H. M. van Vliet
- Gut Health and Food Safety Programme, Institute of Food Research, Norwich Research Park, Norwich, United Kingdom
- * E-mail:
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Philipson CW, Bassaganya-Riera J, Viladomiu M, Kronsteiner B, Abedi V, Hoops S, Michalak P, Kang L, Girardin SE, Hontecillas R. Modeling the Regulatory Mechanisms by Which NLRX1 Modulates Innate Immune Responses to Helicobacter pylori Infection. PLoS One 2015; 10:e0137839. [PMID: 26367386 PMCID: PMC4569576 DOI: 10.1371/journal.pone.0137839] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 08/22/2015] [Indexed: 12/15/2022] Open
Abstract
Helicobacter pylori colonizes half of the world’s population as the dominant member of the gastric microbiota resulting in a lifelong chronic infection. Host responses toward the bacterium can result in asymptomatic, pathogenic or even favorable health outcomes; however, mechanisms underlying the dual role of H. pylori as a commensal versus pathogenic organism are not well characterized. Recent evidence suggests mononuclear phagocytes are largely involved in shaping dominant immunity during infection mediating the balance between host tolerance and succumbing to overt disease. We combined computational modeling, bioinformatics and experimental validation in order to investigate interactions between macrophages and intracellular H. pylori. Global transcriptomic analysis on bone marrow-derived macrophages (BMDM) in a gentamycin protection assay at six time points unveiled the presence of three sequential host response waves: an early transient regulatory gene module followed by sustained and late effector responses. Kinetic behaviors of pattern recognition receptors (PRRs) are linked to differential expression of spatiotemporal response waves and function to induce effector immunity through extracellular and intracellular detection of H. pylori. We report that bacterial interaction with the host intracellular environment caused significant suppression of regulatory NLRC3 and NLRX1 in a pattern inverse to early regulatory responses. To further delineate complex immune responses and pathway crosstalk between effector and regulatory PRRs, we built a computational model calibrated using time-series RNAseq data. Our validated computational hypotheses are that: 1) NLRX1 expression regulates bacterial burden in macrophages; and 2) early host response cytokines down-regulate NLRX1 expression through a negative feedback circuit. This paper applies modeling approaches to characterize the regulatory role of NLRX1 in mechanisms of host tolerance employed by macrophages to respond to and/or to co-exist with intracellular H. pylori.
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Affiliation(s)
- Casandra W. Philipson
- Center for Modeling Immunity to Enteric Pathogens, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, VA, United States of America
- Nutritional Immunology and Molecular Medicine Laboratory, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, VA, United States of America
| | - Josep Bassaganya-Riera
- Center for Modeling Immunity to Enteric Pathogens, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, VA, United States of America
- Nutritional Immunology and Molecular Medicine Laboratory, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, VA, United States of America
- Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, VA, United States of America
| | - Monica Viladomiu
- Center for Modeling Immunity to Enteric Pathogens, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, VA, United States of America
- Nutritional Immunology and Molecular Medicine Laboratory, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, VA, United States of America
| | - Barbara Kronsteiner
- Center for Modeling Immunity to Enteric Pathogens, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, VA, United States of America
- Nutritional Immunology and Molecular Medicine Laboratory, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, VA, United States of America
| | - Vida Abedi
- Center for Modeling Immunity to Enteric Pathogens, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, VA, United States of America
- Nutritional Immunology and Molecular Medicine Laboratory, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, VA, United States of America
| | - Stefan Hoops
- Center for Modeling Immunity to Enteric Pathogens, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, VA, United States of America
- Nutritional Immunology and Molecular Medicine Laboratory, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, VA, United States of America
| | - Pawel Michalak
- Center for Modeling Immunity to Enteric Pathogens, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, VA, United States of America
| | - Lin Kang
- Center for Modeling Immunity to Enteric Pathogens, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, VA, United States of America
| | - Stephen E. Girardin
- Laboratory of Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Raquel Hontecillas
- Center for Modeling Immunity to Enteric Pathogens, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, VA, United States of America
- Nutritional Immunology and Molecular Medicine Laboratory, Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, VA, United States of America
- * E-mail:
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21
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Helicobacter pylori: Genomic Insight into the Host-Pathogen Interaction. Int J Genomics 2015; 2015:386905. [PMID: 25722969 PMCID: PMC4334614 DOI: 10.1155/2015/386905] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 01/09/2015] [Indexed: 12/18/2022] Open
Abstract
The advent of genomic analyses has revolutionized the study of human health. Infectious disease research in particular has experienced an explosion of bacterial genomic, transcriptomic, and proteomic data complementing the phenotypic methods employed in traditional bacteriology. Together, these techniques have revealed novel virulence determinants in numerous pathogens and have provided information for potential chemotherapeutics. The bacterial pathogen, Helicobacter pylori, has been recognized as a class 1 carcinogen and contributes to chronic inflammation within the gastric niche. Genomic analyses have uncovered remarkable coevolution between the human host and H. pylori. Perturbation of this coevolution results in dysregulation of the host-pathogen interaction, leading to oncogenic effects. This review discusses the relationship of H. pylori with the human host and environment and the contribution of each of these factors to disease progression, with an emphasis on features that have been illuminated by genomic tools.
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A variable homopolymeric G-repeat defines small RNA-mediated posttranscriptional regulation of a chemotaxis receptor in Helicobacter pylori. Proc Natl Acad Sci U S A 2014; 111:E501-10. [PMID: 24474799 DOI: 10.1073/pnas.1315152111] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Phase variation of hypermutable simple sequence repeats (SSRs) is a widespread and stochastic mechanism to generate phenotypic variation within a population and thereby contributes to host adaptation of bacterial pathogens. Although several examples of SSRs that affect transcription or coding potential have been reported, we now show that a SSR also impacts small RNA-mediated posttranscriptional regulation. Based on in vitro and in vivo analyses, we demonstrate that a variable homopolymeric G-repeat in the leader of the TlpB chemotaxis receptor mRNA of the human pathogen Helicobacter pylori is directly targeted by a small RNA (sRNA), RepG (Regulator of polymeric G-repeats). Whereas RepG sRNA is highly conserved, the tlpB G-repeat length varies among diverse H. pylori strains, resulting in strain-specific RepG-mediated tlpB regulation. Based on modification of the G-repeat length within one strain, we demonstrate that the G-repeat length determines posttranscriptional regulation and can mediate both repression and activation of tlpB through RepG. In vitro translation assays show that this regulation occurs at the translational level and that RepG influences tlpB translation dependent on the G-repeat length. In contrast to the digital ON-OFF switches through frame-shift mutations within coding sequences, such modulation of posttranscriptional regulation allows for a gradual control of gene expression. This connection to sRNA-mediated posttranscriptional regulation might also apply to other genes with SSRs, which could be targeting sites of cis- or trans-encoded sRNAs, and thereby could facilitate host adaptation through sRNA-mediated fine-tuning of virulence gene expression.
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Mukherjee P, Mani S. Methodologies to decipher the cell secretome. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:2226-32. [PMID: 23376189 DOI: 10.1016/j.bbapap.2013.01.022] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 12/18/2012] [Accepted: 01/17/2013] [Indexed: 11/18/2022]
Abstract
The cell secretome is a collection of proteins consisting of transmembrane proteins (TM) and proteins secreted by cells into the extracellular space. A significant portion (~13-20%) of the human proteome consists of secretory proteins. The secretory proteins play important roles in cell migration, cell signaling and communication. There is a plethora of methodologies available like Serial Analysis of Gene Expression (SAGE), DNA microarrays, antibody arrays and bead-based arrays, mass spectrometry, RNA sequencing and yeast, bacterial and mammalian secretion traps to identify the cell secretomes. There are many advantages and disadvantages in using any of the above methods. This review aims to discuss the methodologies available along with their potential advantages and disadvantages to identify secretory proteins. This review is a part of a Special issue on The Secretome. This article is part of a Special Issue entitled: An Updated Secretome.
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Affiliation(s)
- Paromita Mukherjee
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, 10461, USA.
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Merrell DS, Stintzi A. Research advances in the study of Campylobacter, Helicobacter, and related organisms. Front Cell Infect Microbiol 2012; 2:159. [PMID: 23267439 PMCID: PMC3525878 DOI: 10.3389/fcimb.2012.00159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 11/28/2012] [Indexed: 01/22/2023] Open
Affiliation(s)
- D. Scott Merrell
- Department of Microbiology and Immunology, Uniformed Services UniversityBethesda, MD, USA
- *Correspondence: ;
| | - Alain Stintzi
- Department of Biochemistry, Microbiology and Immunology, University of OttawaOttawa, ON, Canada
- *Correspondence: ;
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