1
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Savin A, Anderson EE, Dyzenhaus S, Podkowik M, Shopsin B, Pironti A, Torres VJ. Staphylococcus aureus senses human neutrophils via PerR to coordinate the expression of the toxin LukAB. Infect Immun 2024; 92:e0052623. [PMID: 38235972 PMCID: PMC10863418 DOI: 10.1128/iai.00526-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 12/20/2023] [Indexed: 01/19/2024] Open
Abstract
Staphylococcus aureus is a gram-positive pathogen that poses a major health concern, in part due to its large array of virulence factors that allow infection and evasion of the immune system. One of these virulence factors is the bicomponent pore-forming leukocidin LukAB. The regulation of lukAB expression is not completely understood, especially in the presence of immune cells such as human polymorphonuclear neutrophils (hPMNs). Here, we screened for transcriptional regulators of lukAB during the infection of primary hPMNs. We uncovered that PerR, a peroxide sensor, is vital for hPMN-mediated induction of lukAB and that PerR upregulates cytotoxicity during the infection of hPMNs. Exposure of S. aureus to hydrogen peroxide (H2O2) alone also results in increased lukAB promoter activity, a phenotype dependent on PerR. Collectively, our data suggest that S. aureus uses PerR to sense the H2O2 produced by hPMNs to stimulate the expression of lukAB, allowing the bacteria to withstand these critical innate immune cells.IMPORTANCEStaphylococcus aureus utilizes a diverse set of virulence factors, such as leukocidins, to subvert human neutrophils, but how these toxins are regulated is incompletely defined. Here, we identified the peroxide-sensitive repressor, PerR, as a required protein involved in the induction of lukAB in the presence of primary human neutrophils, a phenotype directly linked to the ability of PerR to sense H2O2. Thus, we show that S. aureus coordinates sensing and resistance to oxidative stress with toxin production to promote pathogen survival.
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Affiliation(s)
- Avital Savin
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
- Department of Biology, New York University, New York, New York, USA
| | - Exene E. Anderson
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Sophie Dyzenhaus
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Magdalena Podkowik
- Antimicrobial-Resistant Pathogens Program, New York University Grossman School of Medicine, New York, New York, USA
- Division of Infectious Diseases, Department of Medicine, New York University Grossman School of Medicine, New York, New York, USA
| | - Bo Shopsin
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
- Antimicrobial-Resistant Pathogens Program, New York University Grossman School of Medicine, New York, New York, USA
- Division of Infectious Diseases, Department of Medicine, New York University Grossman School of Medicine, New York, New York, USA
| | - Alejandro Pironti
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
- Antimicrobial-Resistant Pathogens Program, New York University Grossman School of Medicine, New York, New York, USA
| | - Victor J. Torres
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
- Department of Host-Microbe Interactions, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
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2
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The Small RNA Teg41 Is a Pleiotropic Regulator of Virulence in Staphylococcus aureus. Infect Immun 2022; 90:e0023622. [PMID: 36214557 PMCID: PMC9670889 DOI: 10.1128/iai.00236-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previously, our group demonstrated a role for the small RNA (sRNA) Teg41 in regulating production of the alpha phenol-soluble modulin toxins (αPSMs) in Staphylococcus aureus. Overexpressing Teg41 increased αPSM production while deleting the 3' end of Teg41 (Teg41Δ3' strain) resulted in a decrease in αPSM production, reduced hemolytic activity of S. aureus culture supernatants, and attenuated virulence in a murine abscess model of infection. In this study, we further explore the attenuation of virulence in the Teg41Δ3' strain. Using both localized and systemic models of infection, we demonstrate that the Teg41Δ3' strain is more severely attenuated than an ΔαPSM mutant, strongly suggesting that Teg41 influences more than the αPSMs. Proteomic and transcriptomic analysis of the wild-type and Teg41Δ3' strains reveals widespread alterations in transcript abundance and protein production in the absence of Teg41, confirming that Teg41 has pleiotropic effects in the cell. We go on to investigate the molecular mechanism underlying Teg41-mediated gene regulation. Surprisingly, results demonstrate that certain Teg41 target genes, including the αPSMs and βPSMs, are transcriptionally altered in the Teg41Δ3' strain, while other targets, specifically spa (encoding surface protein A), are regulated at the level of transcript stability. Collectively, these data demonstrate that Teg41 is a pleiotropic RNA regulator in S. aureus that influences expression of a variety of genes using multiple different mechanisms.
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3
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Manna AC, Leo S, Girel S, González-Ruiz V, Rudaz S, Francois P, Cheung AL. Teg58, a small regulatory RNA, is involved in regulating arginine biosynthesis and biofilm formation in Staphylococcus aureus. Sci Rep 2022; 12:14963. [PMID: 36056144 PMCID: PMC9440087 DOI: 10.1038/s41598-022-18815-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 08/19/2022] [Indexed: 12/02/2022] Open
Abstract
Staphylococcus aureus adapts to different environments by sensing and responding to diverse environmental cues. The responses are coordinately regulated by regulatory proteins, and small regulatory RNAs at the transcriptional and translational levels. Here, we characterized teg58, a SarA repressed sRNA, using ChIP-Seq and RNA-Seq analysis of a sarA mutant. Phenotypic and genetic analyses indicated that inactivation of teg58 led to reduced biofilm formation in a process that is independent of SarA, agr, PIA, and PSMs. RNA-Seq analysis of teg58 mutant revealed up-regulation of arginine biosynthesis genes (i.e., argGH) as well as the ability of the mutant to grow in a chemical defined medium (CDM) lacking L-arginine. Exogenous L-arginine or endogenous induction of argGH led to decreased biofilm formation in parental strains. Further analysis in vitro and in vivo demonstrated that the specific interaction between teg58 and the argGH occurred at the post-transcriptional level to repress arginine synthesis. Biochemical and genetic analyses of various arginine catabolic pathway genes demonstrated that the catabolic pathway did not play a significant role in reduced biofilm formation in the teg58 mutant. Overall, results suggest that teg58 is a regulatory sRNA that plays an important role in modulating arginine biosynthesis and biofilm formation in S. aureus.
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Affiliation(s)
- Adhar C Manna
- Department of Microbiology & Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, 03755, USA.
| | - Stefano Leo
- Genomic Research Laboratory, Service of Infectious Diseases, Geneva University Hospitals and University Medical Center, Rue Michel-Servet 1, 1211, Geneva 4, Switzerland
| | - Sergey Girel
- Institute of Pharmaceutical Sciences of Western Switzerland (ISPSO), School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
- University Medical Center, Rue Michel-Servet 1, 1211, Geneva 4, Switzerland
| | - Víctor González-Ruiz
- Institute of Pharmaceutical Sciences of Western Switzerland (ISPSO), School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
- University Medical Center, Rue Michel-Servet 1, 1211, Geneva 4, Switzerland
| | - Serge Rudaz
- Institute of Pharmaceutical Sciences of Western Switzerland (ISPSO), School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
- University Medical Center, Rue Michel-Servet 1, 1211, Geneva 4, Switzerland
| | - Patrice Francois
- Genomic Research Laboratory, Service of Infectious Diseases, Geneva University Hospitals and University Medical Center, Rue Michel-Servet 1, 1211, Geneva 4, Switzerland
| | - Ambrose L Cheung
- Department of Microbiology & Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, 03755, USA
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4
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Menard G, Silard C, Suriray M, Rouillon A, Augagneur Y. Thirty Years of sRNA-Mediated Regulation in Staphylococcus aureus: From Initial Discoveries to In Vivo Biological Implications. Int J Mol Sci 2022; 23:ijms23137346. [PMID: 35806357 PMCID: PMC9266662 DOI: 10.3390/ijms23137346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/20/2022] [Accepted: 06/28/2022] [Indexed: 01/27/2023] Open
Abstract
Staphylococcus aureus is a widespread livestock and human pathogen that colonizes diverse microenvironments within its host. Its adaptation to the environmental conditions encountered within humans relies on coordinated gene expression. This requires a sophisticated regulatory network, among which regulatory RNAs (usually called sRNAs) have emerged as key players over the last 30 years. In S. aureus, sRNAs regulate target genes at the post-transcriptional level through base–pair interactions. The functional characterization of a subset revealed that they participate in all biological processes, including virulence, metabolic adaptation, and antibiotic resistance. In this review, we report 30 years of S. aureus sRNA studies, from their discovery to the in-depth characterizations of some of them. We also discuss their actual in vivo contribution, which is still lagging behind, and their place within the complex regulatory network. These shall be key aspects to consider in order to clearly uncover their in vivo biological functions.
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Affiliation(s)
- Guillaume Menard
- CHU Rennes, INSERM, BRM (Bacterial Regulatory RNAs and Medicine), SB2H (Service de Bactériologie Hygiène-Hospitalière), University Rennes, UMR_S 1230, F-35000 Rennes, France; (G.M.); (M.S.)
| | - Chloé Silard
- INSERM, BRM (Bacterial Regulatory RNAs and Medicine), University Rennes, UMR_S 1230, F-35000 Rennes, France; (C.S.); (A.R.)
| | - Marie Suriray
- CHU Rennes, INSERM, BRM (Bacterial Regulatory RNAs and Medicine), SB2H (Service de Bactériologie Hygiène-Hospitalière), University Rennes, UMR_S 1230, F-35000 Rennes, France; (G.M.); (M.S.)
| | - Astrid Rouillon
- INSERM, BRM (Bacterial Regulatory RNAs and Medicine), University Rennes, UMR_S 1230, F-35000 Rennes, France; (C.S.); (A.R.)
| | - Yoann Augagneur
- INSERM, BRM (Bacterial Regulatory RNAs and Medicine), University Rennes, UMR_S 1230, F-35000 Rennes, France; (C.S.); (A.R.)
- Correspondence: ; Tel.: +33-223234631
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5
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McKellar SW, Ivanova I, Arede P, Zapf RL, Mercier N, Chu LC, Mediati DG, Pickering AC, Briaud P, Foster RG, Kudla G, Fitzgerald JR, Caldelari I, Carroll RK, Tree JJ, Granneman S. RNase III CLASH in MRSA uncovers sRNA regulatory networks coupling metabolism to toxin expression. Nat Commun 2022; 13:3560. [PMID: 35732654 PMCID: PMC9217828 DOI: 10.1038/s41467-022-31173-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 06/03/2022] [Indexed: 01/13/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterial pathogen responsible for significant human morbidity and mortality. Post-transcriptional regulation by small RNAs (sRNAs) has emerged as an important mechanism for controlling virulence. However, the functionality of the majority of sRNAs during infection is unknown. To address this, we performed UV cross-linking, ligation, and sequencing of hybrids (CLASH) in MRSA to identify sRNA-RNA interactions under conditions that mimic the host environment. Using a double-stranded endoribonuclease III as bait, we uncovered hundreds of novel sRNA-RNA pairs. Strikingly, our results suggest that the production of small membrane-permeabilizing toxins is under extensive sRNA-mediated regulation and that their expression is intimately connected to metabolism. Additionally, we also uncover an sRNA sponging interaction between RsaE and RsaI. Taken together, we present a comprehensive analysis of sRNA-target interactions in MRSA and provide details on how these contribute to the control of virulence in response to changes in metabolism.
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Affiliation(s)
- Stuart W McKellar
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Ivayla Ivanova
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Pedro Arede
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Rachel L Zapf
- Department of Biological Sciences, Ohio University, Athens, OH, 45701, USA
| | - Noémie Mercier
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000, Strasbourg, France
| | - Liang-Cui Chu
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Daniel G Mediati
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, 2052, NSW, Australia
| | - Amy C Pickering
- The Roslin Institute and Edinburgh Infectious Diseases, University of Edinburgh, Easter Bush Campus, Edinburgh, Scotland, UK
| | - Paul Briaud
- Department of Biological Sciences, Ohio University, Athens, OH, 45701, USA
| | - Robert G Foster
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Grzegorz Kudla
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - J Ross Fitzgerald
- The Roslin Institute and Edinburgh Infectious Diseases, University of Edinburgh, Easter Bush Campus, Edinburgh, Scotland, UK
| | - Isabelle Caldelari
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000, Strasbourg, France
| | - Ronan K Carroll
- Department of Biological Sciences, Ohio University, Athens, OH, 45701, USA
- The Infectious and Tropical Disease Institute, Ohio University, Athens, OH, 45701, USA
| | - Jai J Tree
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, 2052, NSW, Australia
| | - Sander Granneman
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK.
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6
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Gonçalves KB, Appel RJC, Bôas LAV, Cardoso PF, Bôas GTV. Genomic insights into the diversity of non-coding RNAs in Bacillus cereus sensu lato. Curr Genet 2022; 68:449-466. [PMID: 35552506 DOI: 10.1007/s00294-022-01240-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 03/20/2022] [Accepted: 03/30/2022] [Indexed: 11/28/2022]
Abstract
Bacillus cereus sensu lato is a group of bacteria of medical and agricultural importance in different ecological niches and with controversial taxonomic relationships. Studying the composition of non-coding RNAs (ncRNAs) in several bacterial groups has been an important tool for identifying genetic information and better understanding genetic regulation towards environment adaptation. However, to date, no comparative genomics study of ncRNA has been performed in this group. Thus, this study aimed to identify and characterize the set of ncRNAs from 132 strains of Bacillus cereus, Bacillus thuringiensis and Bacillus anthracis to obtain an overview of the diversity and distribution of these genetic elements in these species. We observed that the number of ncRNAs differs in the chromosomes of the three species, but not in the plasmids, when species or phylogenetic clusters were compared. The prevailing functional/structural category was Cis-reg and the most frequent class was Riboswitch. However, in plasmids, the class Group II intron was the most frequent. Also, nine ncRNAs were selected for validation in the strain B. thuringiensis 407 by RT-PCR, which allowed to identify the expression of the ncRNAs. The wide distribution and diversity of ncRNAs in the B. cereus group, and more intensely in B. thuringiensis, may help improve the abilities of these species to adapt to various environmental changes. Further studies should address the expression of these genetic elements in different conditions.
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Affiliation(s)
- Kátia B Gonçalves
- Depto Biologia Geral, Universidade Estadual de Londrina, Londrina, Brazil
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7
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Abstract
SarA, a transcriptional regulator of Staphylococcus aureus, is a major global regulatory system that coordinates the expression of target genes involved in its pathogenicity. Various studies have identified a large number of SarA target genes, but an in-depth characterization of the sarA regulon, including small regulatory RNAs (sRNAs), has not yet been done. In this study, we utilized transcriptome sequencing (RNA-Seq) and chromatin immunoprecipitation sequencing (ChIP-Seq) to determine a comprehensive list of SarA-regulated targets, including both mRNAs and sRNAs. RNA-Seq analysis indicated 390 mRNAs and 51 sRNAs differentially expressed in a ΔsarA mutant, while ChIP-Seq revealed 354 mRNAs and 55 sRNA targets in the S. aureus genome. We confirmed the authenticity of several novel SarA targets by Northern blotting and electrophoretic mobility shift assays. Among them, we characterized repression of sprG2, a gene that encodes the toxin of a type I toxin-antitoxin system, indicating a multilayer lockdown of toxin expression by both SarA and its cognate antitoxin, SprF2. Finally, a novel SarA consensus DNA binding sequence was generated using the upstream promoter sequences of 15 novel SarA-regulated sRNA targets. A genome-wide scan with a deduced SarA motif enabled the discovery of new potential SarA target genes which were not identified in our RNA-Seq and ChIP-Seq analyses. The strength of this new consensus was confirmed with one predicted sRNA target. The RNA-Seq and ChIP-Seq combinatory analysis gives a snapshot of the regulation, whereas bioinformatic analysis reveals a permanent view of targets based on sequence. Altogether these experimental and in silico methodologies are effective to characterize transcriptional factor (TF) regulons and functions. IMPORTANCEStaphylococcus aureus, a commensal and opportunist pathogen, is responsible for a large number of human and animal infections, from benign to severe. Gene expression adaptation during infection requires a complex network of regulators, including transcriptional factors (TF) and sRNAs. TF SarA influences virulence, metabolism, biofilm formation, and resistance to some antibiotics. SarA directly regulates expression of around 20 mRNAs and a few sRNAs. Here, we combined high-throughput expression screening methods combined with binding assays and bioinformatics for an in-depth investigation of the SarA regulon. This combinatory approach allowed the identification of 85 unprecedented mRNAs and sRNAs targets, with at least 14 being primary. Among novel SarA direct targets, we characterized repression of sprG2, a gene that encodes the toxin of a toxin-antitoxin system, indicating a multilayer lockdown of toxin expression by both SarA and its cognate antitoxin, SprF2.
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8
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Barrientos L, Mercier N, Lalaouna D, Caldelari I. Assembling the Current Pieces: The Puzzle of RNA-Mediated Regulation in Staphylococcus aureus. Front Microbiol 2021; 12:706690. [PMID: 34367109 PMCID: PMC8334554 DOI: 10.3389/fmicb.2021.706690] [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: 05/07/2021] [Accepted: 06/30/2021] [Indexed: 01/16/2023] Open
Abstract
The success of the major opportunistic human Staphylococcus aureus relies on the production of numerous virulence factors, which allow rapid colonization and dissemination in any tissues. Indeed, regulation of its virulence is multifactorial, and based on the production of transcriptional factors, two-component systems (TCS) and small regulatory RNAs (sRNAs). Advances in high-throughput sequencing technologies have unveiled the existence of hundreds of potential RNAs with regulatory functions, but only a fraction of which have been validated in vivo. These discoveries have modified our thinking and understanding of bacterial physiology and virulence fitness by placing sRNAs, alongside transcriptional regulators, at the center of complex and intertwined regulatory networks that allow S. aureus to rapidly adapt to the environmental cues present at infection sites. In this review, we describe the recently acquired knowledge of characterized regulatory RNAs in S. aureus that are associated with metal starvation, nutrient availability, stress responses and virulence. These findings highlight the importance of sRNAs for the comprehension of S. aureus infection processes while raising questions about the interplay between these key regulators and the pathways they control.
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Affiliation(s)
- Laura Barrientos
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, Strasbourg, France
| | - Noémie Mercier
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, Strasbourg, France
| | - David Lalaouna
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, Strasbourg, France
| | - Isabelle Caldelari
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, Strasbourg, France
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9
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Hibernation-Promoting Factor Sequesters Staphylococcus aureus Ribosomes to Antagonize RNase R-Mediated Nucleolytic Degradation. mBio 2021; 12:e0033421. [PMID: 34253058 PMCID: PMC8406268 DOI: 10.1128/mbio.00334-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Bacterial and eukaryotic hibernation factors prevent translation by physically blocking the decoding center of ribosomes, a phenomenon called ribosome hibernation that often occurs in response to nutrient deprivation. The human pathogen Staphylococcus aureus lacking the sole hibernation factor HPF undergoes massive ribosome degradation via an unknown pathway. Using genetic and biochemical approaches, we find that inactivating the 3′-to-5′ exonuclease RNase R suppresses ribosome degradation in the Δhpf mutant. In vitro cell-free degradation assays confirm that 30S and 70S ribosomes isolated from the Δhpf mutant are extremely susceptible to RNase R, in stark contrast to nucleolytic resistance of the HPF-bound 70S and 100S complexes isolated from the wild type. In the absence of HPF, specific S. aureus 16S rRNA helices are sensitive to nucleolytic cleavage. These RNase hot spots are distinct from that found in the Escherichia coli ribosomes. S. aureus RNase R is associated with ribosomes, but unlike the E. coli counterpart, it is not regulated by general stressors and acetylation. The results not only highlight key differences between the evolutionarily conserved RNase R homologs but also provide direct evidence that HPF preserves ribosome integrity beyond its role in translational avoidance, thereby poising the hibernating ribosomes for rapid resumption of translation.
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10
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Correia Santos S, Bischler T, Westermann AJ, Vogel J. MAPS integrates regulation of actin-targeting effector SteC into the virulence control network of Salmonella small RNA PinT. Cell Rep 2021; 34:108722. [PMID: 33535041 DOI: 10.1016/j.celrep.2021.108722] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/25/2020] [Accepted: 01/13/2021] [Indexed: 10/22/2022] Open
Abstract
A full understanding of the contribution of small RNAs (sRNAs) to bacterial virulence demands knowledge of their target suites under infection-relevant conditions. Here, we take an integrative approach to capturing targets of the Hfq-associated sRNA PinT, a known post-transcriptional timer of the two major virulence programs of Salmonella enterica. Using MS2 affinity purification and RNA sequencing (MAPS), we identify PinT ligands in bacteria under in vitro conditions mimicking specific stages of the infection cycle and in bacteria growing inside macrophages. This reveals PinT-mediated translational inhibition of the secreted effector kinase SteC, which had gone unnoticed in previous target searches. Using genetic, biochemical, and microscopic assays, we provide evidence for PinT-mediated repression of steC mRNA, eventually delaying actin rearrangements in infected host cells. Our findings support the role of PinT as a central post-transcriptional regulator in Salmonella virulence and illustrate the need for complementary methods to reveal the full target suites of sRNAs.
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Affiliation(s)
- Sara Correia Santos
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Thorsten Bischler
- Core Unit Systems Medicine, University of Würzburg, Würzburg, Germany
| | - Alexander J Westermann
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany; Helmholtz Institute for RNA-Based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany.
| | - Jörg Vogel
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany; Helmholtz Institute for RNA-Based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany.
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11
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Joshi B, Singh B, Nadeem A, Askarian F, Wai SN, Johannessen M, Hegstad K. Transcriptome Profiling of Staphylococcus aureus Associated Extracellular Vesicles Reveals Presence of Small RNA-Cargo. Front Mol Biosci 2021; 7:566207. [PMID: 33521050 PMCID: PMC7838569 DOI: 10.3389/fmolb.2020.566207] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 12/14/2020] [Indexed: 12/13/2022] Open
Abstract
Bacterial extracellular vesicles (EVs) have a vital role in bacterial pathogenesis. However, to date, the small RNA-cargo of EVs released by the opportunistic pathogen Staphylococcus aureus has not been characterized. Here, we shed light on the association of small RNAs with EVs secreted by S. aureus MSSA476 cultured in iron-depleted bacteriologic media supplemented with a subinhibitory dosage of vancomycin to mimic infection condition. Confocal microscopy analysis on intact RNase-treated EVs indicated that RNA is associated with EV particles. Transcriptomic followed by bioinformatics analysis of EV-associated RNA revealed the presence of potential gene regulatory small RNAs and high levels of tRNAs. Among the EV-associated enriched small RNAs were SsrA, RsaC and RNAIII. Our finding invites new insights into the potential role of EV-associated RNA as a modulator of host-pathogen interaction.
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Affiliation(s)
- Bishnu Joshi
- Department of Medical Biology, Research Group for Host-Microbe Interactions, UiT The Arctic University of Norway, Tromsø, Norway
| | - Bhupender Singh
- Department of Medical Biology, Research Group for Host-Microbe Interactions, UiT The Arctic University of Norway, Tromsø, Norway
| | - Aftab Nadeem
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden.,Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Fatemeh Askarian
- Department of Medical Biology, Research Group for Host-Microbe Interactions, UiT The Arctic University of Norway, Tromsø, Norway.,Faculty of Chemistry, Biotechnology and Food Science, The Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Sun Nyunt Wai
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden.,Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Mona Johannessen
- Department of Medical Biology, Research Group for Host-Microbe Interactions, UiT The Arctic University of Norway, Tromsø, Norway
| | - Kristin Hegstad
- Department of Medical Biology, Research Group for Host-Microbe Interactions, UiT The Arctic University of Norway, Tromsø, Norway.,Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North-Norway, Tromsø, Norway
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12
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Piattelli E, Peltier J, Soutourina O. Interplay between Regulatory RNAs and Signal Transduction Systems during Bacterial Infection. Genes (Basel) 2020; 11:E1209. [PMID: 33081172 PMCID: PMC7602753 DOI: 10.3390/genes11101209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/08/2020] [Accepted: 10/13/2020] [Indexed: 12/13/2022] Open
Abstract
The ability of pathogenic bacteria to stably infect the host depends on their capacity to respond and adapt to the host environment and on the efficiency of their defensive mechanisms. Bacterial envelope provides a physical barrier protecting against environmental threats. It also constitutes an important sensory interface where numerous sensing systems are located. Signal transduction systems include Two-Component Systems (TCSs) and alternative sigma factors. These systems are able to sense and respond to the ever-changing environment inside the host, altering the bacterial transcriptome to mitigate the impact of the stress. The regulatory networks associated with signal transduction systems comprise small regulatory RNAs (sRNAs) that can be directly involved in the expression of virulence factors. The aim of this review is to describe the importance of TCS- and alternative sigma factor-associated sRNAs in human pathogens during infection. The currently available genome-wide approaches for studies of TCS-regulated sRNAs will be discussed. The differences in the signal transduction mediated by TCSs between bacteria and higher eukaryotes and the specificity of regulatory RNAs for their targets make them appealing targets for discovery of new strategies to fight against multi-resistant bacteria.
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Affiliation(s)
- Emma Piattelli
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Université Paris-Saclay, 91198 Gif-sur-Yvette, France; (E.P.); (J.P.)
| | - Johann Peltier
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Université Paris-Saclay, 91198 Gif-sur-Yvette, France; (E.P.); (J.P.)
- Laboratoire Pathogenèses des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, 75015 Paris, France
| | - Olga Soutourina
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Université Paris-Saclay, 91198 Gif-sur-Yvette, France; (E.P.); (J.P.)
- Institut Universitaire de France, CEDEX 05, 75231 Paris, France
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13
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Inference of Bacterial Small RNA Regulatory Networks and Integration with Transcription Factor-Driven Regulatory Networks. mSystems 2020; 5:5/3/e00057-20. [PMID: 32487739 PMCID: PMC8534726 DOI: 10.1128/msystems.00057-20] [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: 12/11/2022] Open
Abstract
Small noncoding RNAs (sRNAs) are key regulators of bacterial gene expression. Through complementary base pairing, sRNAs affect mRNA stability and translation efficiency. Here, we describe a network inference approach designed to identify sRNA-mediated regulation of transcript levels. We use existing transcriptional data sets and prior knowledge to infer sRNA regulons using our network inference tool, the Inferelator. This approach produces genome-wide gene regulatory networks that include contributions by both transcription factors and sRNAs. We show the benefits of estimating and incorporating sRNA activities into network inference pipelines using available experimental data. We also demonstrate how these estimated sRNA regulatory activities can be mined to identify the experimental conditions where sRNAs are most active. We uncover 45 novel experimentally supported sRNA-mRNA interactions in Escherichia coli, outperforming previous network-based efforts. Additionally, our pipeline complements sequence-based sRNA-mRNA interaction prediction methods by adding a data-driven filtering step. Finally, we show the general applicability of our approach by identifying 24 novel, experimentally supported, sRNA-mRNA interactions in Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis. Overall, our strategy generates novel insights into the functional context of sRNA regulation in multiple bacterial species. IMPORTANCE Individual bacterial genomes can have dozens of small noncoding RNAs with largely unexplored regulatory functions. Although bacterial sRNAs influence a wide range of biological processes, including antibiotic resistance and pathogenicity, our current understanding of sRNA-mediated regulation is far from complete. Most of the available information is restricted to a few well-studied bacterial species; and even in those species, only partial sets of sRNA targets have been characterized in detail. To close this information gap, we developed a computational strategy that takes advantage of available transcriptional data and knowledge about validated and putative sRNA-mRNA interactions for inferring expanded sRNA regulons. Our approach facilitates the identification of experimentally supported novel interactions while filtering out false-positive results. Due to its data-driven nature, our method prioritizes biologically relevant interactions among lists of candidate sRNA-target pairs predicted in silico from sequence analysis or derived from sRNA-mRNA binding experiments.
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14
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Comparative Transcriptomic and Functional Assessments of Linezolid-Responsive Small RNA Genes in Staphylococcus aureus. mSystems 2020; 5:5/1/e00665-19. [PMID: 31911464 PMCID: PMC6946794 DOI: 10.1128/msystems.00665-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Bacterial small RNAs (sRNAs) are RNA molecules that can have important regulatory roles across gene expression networks. There is a growing understanding of the scope and potential breadth of impact of sRNAs on global gene expression patterns in Staphylococcus aureus, a major human pathogen. Here, transcriptome comparisons were used to examine the roles of sRNA genes with a potential role in the response of S. aureus to antibiotic exposure. Although no measurable impact on key bacterial phenotypes was observed after deleting each of 18 sRNAs identified by these comparisons, this research is significant because it underscores the subtle modes of action of these sometimes abundant molecules within the bacterium. Staphylococcus aureus contains a repertoire of at least 50 and possibly 500 small RNAs (sRNAs). The functions of most sRNAs are not understood, although some are known to respond to environmental changes, including the presence of antibiotics. Here, in an effort to better understand the roles of sRNAs in the context of antibiotic exposure, we took a clinical methicillin-resistant S. aureus (MRSA) isolate and separately deleted eight sRNAs that were significantly upregulated in response to the last-line antibiotic linezolid as revealed by transcriptome sequencing (RNA-seq) comparisons. We also deleted an additional 10 sRNAs that were either highly expressed or previously found to respond to antibiotic exposure. There were no significant changes for any of the 18 mutants in a variety of phenotypic screens, including MIC screens, growth competition assays in the presence of linezolid, biofilm formation, and resistance to whole-blood killing. These data suggest sRNA functional redundancy, because despite their high expression levels upon antibiotic exposure, individual sRNA genes do not affect readily observable bacterial phenotypes. The sRNA transcriptional changes we measured during antibiotic exposure might also reflect sRNA “indifference,” that is, a general stress response not specifically related to sRNA function. These data underscore the need for sensitive assays and new approaches to try and decipher the functions of sRNA genes in S. aureus. IMPORTANCE Bacterial small RNAs (sRNAs) are RNA molecules that can have important regulatory roles across gene expression networks. There is a growing understanding of the scope and potential breadth of impact of sRNAs on global gene expression patterns in Staphylococcus aureus, a major human pathogen. Here, transcriptome comparisons were used to examine the roles of sRNA genes with a potential role in the response of S. aureus to antibiotic exposure. Although no measurable impact on key bacterial phenotypes was observed after deleting each of 18 sRNAs identified by these comparisons, this research is significant because it underscores the subtle modes of action of these sometimes abundant molecules within the bacterium.
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15
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Augagneur Y, King AN, Germain-Amiot N, Sassi M, Fitzgerald JW, Sahukhal GS, Elasri MO, Felden B, Brinsmade SR. Analysis of the CodY RNome reveals RsaD as a stress-responsive riboregulator of overflow metabolism in Staphylococcus aureus. Mol Microbiol 2019; 113:309-325. [PMID: 31696578 DOI: 10.1111/mmi.14418] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/05/2019] [Indexed: 11/28/2022]
Abstract
In Staphylococcus aureus, the transcription factor CodY modulates the expression of hundreds of genes, including most virulence factors, in response to the availability of key nutrients like GTP and branched-chain amino acids. Despite numerous studies examining how CodY controls gene expression directly or indirectly, virtually nothing is known about the extent to which CodY exerts its effect through small regulatory RNAs (sRNAs). Herein, we report the first set of sRNAs under the control of CodY. We reveal that staphylococcal sRNA RsaD is overexpressed >20-fold in a CodY-deficient strain in three S. aureus clinical isolates and in S. epidermidis. We validated the CodY-dependent regulation of rsaD and demonstrated that CodY directly represses rsaD expression by binding the promoter. Using a combination of molecular techniques, we show that RsaD posttranscriptionally regulates alsS (acetolactate synthase) mRNA and enzyme levels. We further show that RsaD redirects carbon overflow metabolism, contributing to stationary phase cell death during exposure to weak acid stress. Taken together, our data delineate a role for CodY in controlling sRNA expression in a major human pathogen and indicate that RsaD may integrate nutrient depletion and other signals to mount a response to physiological stress experienced by S. aureus in diverse environments.
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Affiliation(s)
- Yoann Augagneur
- INSERM U1230 Biochimie Pharmaceutique, Université de Rennes I, Rennes, France
| | - Alyssa N King
- Department of Biology, Georgetown University, Washington, DC, USA
| | | | - Mohamed Sassi
- INSERM U1230 Biochimie Pharmaceutique, Université de Rennes I, Rennes, France
| | | | - Gyan S Sahukhal
- Center of Molecular and Cellular Biosciences, The University of Southern Mississippi, Hattiesburg, MS, USA
| | - Mohamed O Elasri
- Center of Molecular and Cellular Biosciences, The University of Southern Mississippi, Hattiesburg, MS, USA
| | - Brice Felden
- INSERM U1230 Biochimie Pharmaceutique, Université de Rennes I, Rennes, France
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16
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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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17
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Abstract
Regulatory RNAs, present in many bacterial genomes and particularly in pathogenic bacteria such as Staphylococcus aureus, control the expression of genes encoding virulence factors or metabolic proteins. They are extremely diverse and include noncoding RNAs (sRNA), antisense RNAs, and some 5' or 3' untranslated regions of messenger RNAs that act as sensors for metabolites, tRNAs, or environmental conditions (e.g., temperature, pH). In this review we focus on specific examples of sRNAs of S. aureus that illustrate how numerous sRNAs and associated proteins are embedded in complex networks of regulation. In addition, we discuss the CRISPR-Cas systems defined as an RNA-interference-like mechanism, which also exist in staphylococcal strains.
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18
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Small RNA teg49 Is Derived from a sarA Transcript and Regulates Virulence Genes Independent of SarA in Staphylococcus aureus. Infect Immun 2018; 86:IAI.00635-17. [PMID: 29133345 DOI: 10.1128/iai.00635-17] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Accepted: 10/30/2017] [Indexed: 01/08/2023] Open
Abstract
Expression of virulence factors in Staphylococcus aureus is regulated by a wide range of transcriptional regulators, including proteins and small RNAs (sRNAs), at the level of transcription and/or translation. The sarA locus consists of three overlapping transcripts generated from three distinct promoters, all containing the sarA open reading frame (ORF). The 5' untranslated regions (UTRs) of these transcripts contain three separate regions ∼711, 409, and 146 nucleotides (nt) upstream of the sarA translation start, the functions of which remain unknown. Recent transcriptome-sequencing (RNA-Seq) analysis and subsequent characterization indicated that two sRNAs, teg49 and teg48, are processed and likely produced from the sarA P3 and sarA P1 transcripts of the sarA locus, respectively. In this report, we utilized a variety of sarA promoter mutants and cshA and rnc mutants to ascertain the contributions of these factors to the generation of teg49. We also defined the transcriptional regulon of teg49, including virulence genes not regulated by SarA. Phenotypically, teg49 did not impact biofilm formation or affect overall SarA expression significantly. Comparative analyses of RNA-Seq data between the wild-type, teg49 mutant, and sarA mutant strains indicated that ∼133 genes are significantly upregulated while 97 are downregulated in a teg49 deletion mutant in a sarA-independent manner. An abscess model of skin infection indicated that the teg49 mutant exhibited a reduced bacterial load compared to the wild-type S. aureus Overall, these results suggest that teg49 sRNA has a regulatory role in target gene regulation independent of SarA. The exact mechanism of this regulation is yet to be dissected.
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19
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Horn J, Stelzner K, Rudel T, Fraunholz M. Inside job: Staphylococcus aureus host-pathogen interactions. Int J Med Microbiol 2017; 308:607-624. [PMID: 29217333 DOI: 10.1016/j.ijmm.2017.11.009] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 11/17/2017] [Accepted: 11/21/2017] [Indexed: 12/21/2022] Open
Abstract
Staphylococcus aureus is a notorious opportunistic pathogen causing a plethora of diseases. Recent research established that once phagocytosed by neutrophils and macrophages, a certain percentage of S. aureus is able to survive within these phagocytes which thereby even may contribute to dissemination of the pathogen. S. aureus further induces its uptake by otherwise non-phagocytic cells and the ensuing intracellular cytotoxicity is suggested to lead to tissue destruction, whereas bacterial persistence within cells is thought to lead to immune evasion and chronicity of infections. We here review recent work on the S. aureus host pathogen interactions with a focus on the intracellular survival of the pathogen.
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Affiliation(s)
- Jessica Horn
- Chair of Microbiology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Kathrin Stelzner
- Chair of Microbiology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Thomas Rudel
- Chair of Microbiology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Martin Fraunholz
- Chair of Microbiology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
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20
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Sheehan LM, Caswell CC. An account of evolutionary specialization: the AbcR small RNAs in the Rhizobiales. Mol Microbiol 2017; 107:24-33. [PMID: 29076560 DOI: 10.1111/mmi.13869] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2017] [Indexed: 01/26/2023]
Abstract
The AbcR small RNAs (sRNAs) are a fascinating example of two highly conserved sRNAs that differ tremendously at the functional level among organisms. From their transcriptional activation to their regulatory capabilities, the AbcR sRNAs exhibit varying characteristics in three well-studied bacteria belonging to the Rhizobiales order: the plant symbiont Sinorhizobium meliloti, the plant pathogen Agrobacterium tumefaciens, and the animal pathogen Brucella abortus. This review outlines the similarities and differences of the AbcR sRNAs between each of these organisms, and discusses reasons as to why this group of sRNAs has diverged in their genetic organization and regulatory functions across species. In the end, this review will shed light on how regulatory systems, although seemingly conserved among bacteria, can vary based on the environmental niche and lifestyle of an organism.
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Affiliation(s)
- Lauren M Sheehan
- Department of Biomedical Sciences and Pathobiology, VA-MD College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, USA
| | - Clayton C Caswell
- Department of Biomedical Sciences and Pathobiology, VA-MD College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, USA
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21
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Zhao H, Hu F, Yang H, Ding B, Xu X, He C, Cui Z, Shu W, Liu Q. Isobaric tags for relative and absolute quantitation proteomics analysis of gene regulation by SprC in Staphylococcus aureus. Future Microbiol 2017; 12:1181-1199. [PMID: 28876151 DOI: 10.2217/fmb-2017-0033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AIM To explore the complete gene networks regulated by small RNA SprC and its targets in Staphylococcus aureus. MATERIALS & METHODS The isobaric tags for relative and absolute quantitation and bioinformatic methods were utilized to identify and analyze the target proteins affected by SprC in S. aureus N315. RESULTS Proteomic analysis showed that the expression of 44 proteins was modulated by SprC. Further, bioinformatic analysis displayed that these affected proteins mainly associated with metabolic and cellular process, biological regulation and catalytic activity. CONCLUSION Our data provide a rich resource of SprC targets in S. aureus, although the mechanism of regulation by SprC is yet to be elucidated.
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Affiliation(s)
- Huanqiang Zhao
- Department of Clinical Laboratory, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Fupin Hu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
| | - Han Yang
- Department of Clinical Laboratory, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Baixing Ding
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiaogang Xu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
| | - Chunyan He
- Department of Clinical Laboratory, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Zelin Cui
- Department of Clinical Laboratory, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Wen Shu
- Department of Clinical Laboratory, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Qingzhong Liu
- Department of Clinical Laboratory, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
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22
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Cousin FJ, Lynch DB, Chuat V, Bourin MJB, Casey PG, Dalmasso M, Harris HMB, McCann A, O'Toole PW. A long and abundant non-coding RNA in Lactobacillus salivarius. Microb Genom 2017; 3:e000126. [PMID: 29114404 PMCID: PMC5643018 DOI: 10.1099/mgen.0.000126] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 06/21/2017] [Indexed: 01/12/2023] Open
Abstract
Lactobacillus salivarius, found in the intestinal microbiota of humans and animals, is studied as an example of the sub-dominant intestinal commensals that may impart benefits upon their host. Strains typically harbour at least one megaplasmid that encodes functions contributing to contingency metabolism and environmental adaptation. RNA sequencing (RNA-seq)transcriptomic analysis of L. salivarius strain UCC118 identified the presence of a novel unusually abundant long non-coding RNA (lncRNA) encoded by the megaplasmid, and which represented more than 75 % of the total RNA-seq reads after depletion of rRNA species. The expression level of this 520 nt lncRNA in L. salivarius UCC118 exceeded that of the 16S rRNA, it accumulated during growth, was very stable over time and was also expressed during intestinal transit in a mouse. This lncRNA sequence is specific to the L. salivarius species; however, among 45 L. salivarius genomes analysed, not all (only 34) harboured the sequence for the lncRNA. This lncRNA was produced in 27 tested L. salivarius strains, but at strain-specific expression levels. High-level lncRNA expression correlated with high megaplasmid copy number. Transcriptome analysis of a deletion mutant lacking this lncRNA identified altered expression levels of genes in a number of pathways, but a definitive function of this new lncRNA was not identified. This lncRNA presents distinctive and unique properties, and suggests potential basic and applied scientific developments of this phenomenon.
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Affiliation(s)
- Fabien J Cousin
- 1School of Microbiology, University College Cork, Cork, Ireland.,2APC Microbiome Institute, University College Cork, Cork, Ireland
| | - Denise B Lynch
- 1School of Microbiology, University College Cork, Cork, Ireland.,2APC Microbiome Institute, University College Cork, Cork, Ireland
| | - Victoria Chuat
- 1School of Microbiology, University College Cork, Cork, Ireland.,2APC Microbiome Institute, University College Cork, Cork, Ireland
| | - Maxence J B Bourin
- 1School of Microbiology, University College Cork, Cork, Ireland.,2APC Microbiome Institute, University College Cork, Cork, Ireland
| | - Pat G Casey
- 1School of Microbiology, University College Cork, Cork, Ireland.,2APC Microbiome Institute, University College Cork, Cork, Ireland
| | - Marion Dalmasso
- 1School of Microbiology, University College Cork, Cork, Ireland.,2APC Microbiome Institute, University College Cork, Cork, Ireland
| | - Hugh M B Harris
- 1School of Microbiology, University College Cork, Cork, Ireland.,2APC Microbiome Institute, University College Cork, Cork, Ireland
| | - Angela McCann
- 1School of Microbiology, University College Cork, Cork, Ireland.,2APC Microbiome Institute, University College Cork, Cork, Ireland
| | - Paul W O'Toole
- 2APC Microbiome Institute, University College Cork, Cork, Ireland.,1School of Microbiology, University College Cork, Cork, Ireland
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23
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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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24
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Samuels DJ, Wang Z, Rhee KY, Brinsmade SR. A Tandem Liquid Chromatography-Mass Spectrometry-based Approach for Metabolite Analysis of Staphylococcus aureus. J Vis Exp 2017. [PMID: 28448019 DOI: 10.3791/55558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In an effort to thwart bacterial pathogens, hosts often limit the availability of nutrients at the site of infection. This limitation can alter the abundances of key metabolites to which regulatory factors respond, adjusting cellular metabolism. In recent years, a number of proteins and RNA have emerged as important regulators of virulence gene expression. For example, the CodY protein responds to levels of branched-chain amino acids and GTP and is widely conserved in low G+C Gram-positive bacteria. As a global regulator in Staphylococcus aureus, CodY controls the expression of dozens of virulence and metabolic genes. We hypothesize that S. aureus uses CodY, in part, to alter its metabolic state in an effort to adapt to nutrient-limiting conditions potentially encountered in the host environment. This manuscript describes a method for extracting and analyzing metabolites from S. aureus using liquid chromatography coupled with mass spectrometry, a protocol that was developed to test this hypothesis. The method also highlights best practices that will ensure rigor and reproducibility, such as maintaining biological steady state and constant aeration without the use of continuous chemostat cultures. Relative to the USA200 methicillin-susceptible S. aureus isolate UAMS-1 parental strain, the isogenic codY mutant exhibited significant increases in amino acids derived from aspartate (e.g., threonine and isoleucine) and decreases in their precursors (e.g., aspartate and O-acetylhomoserine). These findings correlate well with transcriptional data obtained with RNA-seq analysis: genes in these pathways were up-regulated between 10- and 800-fold in the codY null mutant. Coupling global analyses of the transcriptome and the metabolome can reveal how bacteria alter their metabolism when faced with environmental or nutritional stress, providing potential insight into the physiological changes associated with nutrient depletion experienced during infection. Such discoveries may pave the way for the development of novel anti-infectives and therapeutics.
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Affiliation(s)
| | - Zhe Wang
- Division of Infectious Diseases, Weill Cornell Medical College
| | - Kyu Y Rhee
- Division of Infectious Diseases, Weill Cornell Medical College; Department of Medicine, Weill Cornell Medical College
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25
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Mauro T, Rouillon A, Felden B. Insights into the regulation of small RNA expression: SarA represses the expression of two sRNAs in Staphylococcus aureus. Nucleic Acids Res 2016; 44:10186-10200. [PMID: 27596601 PMCID: PMC5137438 DOI: 10.1093/nar/gkw777] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 08/09/2016] [Accepted: 08/24/2016] [Indexed: 11/14/2022] Open
Abstract
The opportunistic pathogen Staphylococcus aureus expresses transcription factors (TFs) and regulatory small RNAs (sRNAs) which are essential for bacterial adaptation and infectivity. Until recently, the study of S. aureus sRNA gene expression regulation was under investigated, but it is now an expanding field. Here we address the regulation of Srn_3610_SprC sRNA, an attenuator of S. aureus virulence. We demonstrate that SarA TF represses srn_3610_sprC transcription. DNase I footprinting and deletion analyses show that the SarA binding site on srn_3610_sprC belongs to an essential 22 bp DNA region. Comparative analysis also revealed another possible site, this time in the srn_9340 promoter. SarA specifically binds these two sRNA promoters with high affinity in vitro and also represses their transcription in vivo. Chromatin immunoprecipitation (ChIP) assays confirmed SarA attachment to both promoters. ChIP and electrophoretic mobility shift assays targeting σA RNA polymerase subunit or using bacterial RNA polymerase holoenzyme suggested that SarA and the σA bind srn_3610_sprC and srn_9340 promoters in a mutually exclusive way. Beyond the mechanistic study of SarA repression of these two sRNAs, this work also suggests that some S. aureus sRNAs belong to the same regulon and act jointly in responding to environmental changes.
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Affiliation(s)
- Tony Mauro
- Inserm U835, Biochimie Pharmaceutique, University of Rennes 1, 35000 Rennes, France
| | - Astrid Rouillon
- Inserm U835, Biochimie Pharmaceutique, University of Rennes 1, 35000 Rennes, France
| | - Brice Felden
- Inserm U835, Biochimie Pharmaceutique, University of Rennes 1, 35000 Rennes, France
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26
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den Reijer PM, Haisma EM, Lemmens-den Toom NA, Willemse J, Koning RA, Demmers JAA, Dekkers DHW, Rijkers E, El Ghalbzouri A, Nibbering PH, van Wamel W. Detection of Alpha-Toxin and Other Virulence Factors in Biofilms of Staphylococcus aureus on Polystyrene and a Human Epidermal Model. PLoS One 2016; 11:e0145722. [PMID: 26741798 PMCID: PMC4704740 DOI: 10.1371/journal.pone.0145722] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 12/07/2015] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND & AIM The ability of Staphylococcus aureus to successfully colonize (a)biotic surfaces may be explained by biofilm formation and the actions of virulence factors. The aim of the present study was to establish the presence of 52 proteins, including virulence factors such as alpha-toxin, during biofilm formation of five different (methicillin resistant) S. aureus strains on Leiden human epidermal models (LEMs) and polystyrene surfaces (PS) using a competitive Luminex-based assay. RESULTS All five S. aureus strains formed biofilms on PS, whereas only three out of five strains formed biofilms on LEMs. Out of the 52 tested proteins, six functionally diverse proteins (ClfB, glucosaminidase, IsdA, IsaA, SACOL0688 and nuclease) were detected in biofilms of all strains on both PS and LEMs. At the same time, four toxins (alpha-toxin, gamma-hemolysin B and leukocidins D and E), two immune modulators (formyl peptide receptor-like inhibitory protein and Staphylococcal superantigen-like protein 1), and two other proteins (lipase and LytM) were detectable in biofilms by all five S. aureus strains on LEMs, but not on PS. In contrast, fibronectin-binding protein B (FnbpB) was detectable in biofilms by all S. aureus biofilms on PS, but not on LEMs. These data were largely confirmed by the results from proteomic and transcriptomic analyses and in case of alpha-toxin additionally by GFP-reporter technology. CONCLUSION Functionally diverse virulence factors of (methicillin-resistant) S. aureus are present during biofilm formation on LEMs and PS. These results could aid in identifying novel targets for future treatment strategies against biofilm-associated infections.
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Affiliation(s)
- P. M. den Reijer
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
- * E-mail:
| | - E. M. Haisma
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
- Department of Dermatology, Leiden University Medical Center, Leiden, The Netherlands
| | - N. A. Lemmens-den Toom
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - J. Willemse
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - R. A. Koning
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - J. A. A. Demmers
- Proteomics Centre, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - D. H. W. Dekkers
- Proteomics Centre, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - E. Rijkers
- Proteomics Centre, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - A. El Ghalbzouri
- Department of Dermatology, Leiden University Medical Center, Leiden, The Netherlands
| | - P. H. Nibbering
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - W. van Wamel
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
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27
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Rao Q, Shang W, Hu X, Rao X. Staphylococcus aureus ST121: a globally disseminated hypervirulent clone. J Med Microbiol 2015; 64:1462-1473. [PMID: 26445995 DOI: 10.1099/jmm.0.000185] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Staphylococcus aureus is a leading cause of bacterial infections in hospitals and communities worldwide. With the development of typing methods, several pandemic clones have been well characterized, including the extensively spreading hospital-associated meticillin-resistant S. aureus (HA-MRSA) clone ST239 and the emerging hypervirulent community-associated (CA) MRSA clone USA300. The multilocus sequence typing method was set up based on seven housekeeping genes; S. aureus groups were defined by the sharing of alleles at ≥ 5 of the seven loci. In many cases, the predicted founder of a group would also be the most prevalent ST within the group. As a predicted founder of major S. aureus groups, approximately 90 % of ST121 strains was meticillin-susceptible S. aureus (MSSA). The majority of ST121 strains carry accessory gene regulator type IV, whereas staphylococcal protein A gene types for ST121 are exceptionally diverse. More than 90 % of S. aureus ST121 strains have Panton-Valentine leukocidin; other enterotoxins, haemolysins, leukocidins and exfoliative toxins also contribute to the high virulence of ST121 strains. Patients suffering from S. aureus ST121 infections often need longer hospitalization and prolonged antimicrobial therapy. In this review, we tried to summarize the epidemiology of the S. aureus clone ST121 and focused on the molecular types, toxin carriage and disease spectrum of this globally disseminated clone.
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Affiliation(s)
- Qing Rao
- Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, PR China
| | - Weilong Shang
- Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, PR China
| | - Xiaomei Hu
- Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, PR China
| | - Xiancai Rao
- Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, PR China
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Le Pabic H, Germain-Amiot N, Bordeau V, Felden B. A bacterial regulatory RNA attenuates virulence, spread and human host cell phagocytosis. Nucleic Acids Res 2015; 43:9232-48. [PMID: 26240382 PMCID: PMC4627067 DOI: 10.1093/nar/gkv783] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 07/21/2015] [Indexed: 12/23/2022] Open
Abstract
Staphylococcus aureus pathogenesis is directed by regulatory proteins and RNAs. We report the case of an RNA attenuating virulence and host uptake, possibly to sustain commensalism. A S. aureus sRNA, SprC (srn_3610), reduced virulence and bacterial loads in a mouse infection model. S. aureus deleted for sprC became more virulent and increased bacterial dissemination in colonized animals. Conversely, inducing SprC expression lowered virulence and the bacterial load. Without sprC, S. aureus phagocytosis by monocytes and macrophages was higher, whereas bacteria were internalized at lower yields when SprC expression was stimulated. Without sprC, higher internalization led to a greater number of extracellular bacteria, facilitating colonization. SprC expression decreased after phagocytosis, concurring with the facilitated growth of bacteria lacking the sRNA in the presence of an oxidant. The major staphylococcal autolysin facilitates S. aureus uptake by human phagocytes. ATL proved to be negatively regulated by SprC. The SprC domains involved in pairing with atl mRNA were analyzed. The addition of ATL reduced phagocytosis of bacteria lacking sprC with no effects on wild-type bacterial uptake, implying that SprC influences phagocytosis, at least in part, by controlling ATL. Since the control of SprC on ATL was modest, other factors must contribute to atl regulation.
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Affiliation(s)
- Hélène Le Pabic
- Inserm U835-Upres EA2311, Biochimie Pharmaceutique, Rennes University, 2 av. du prof. Léon Bernard, 35000 Rennes, France
| | - Noëlla Germain-Amiot
- Inserm U835-Upres EA2311, Biochimie Pharmaceutique, Rennes University, 2 av. du prof. Léon Bernard, 35000 Rennes, France
| | - Valérie Bordeau
- Inserm U835-Upres EA2311, Biochimie Pharmaceutique, Rennes University, 2 av. du prof. Léon Bernard, 35000 Rennes, France
| | - Brice Felden
- Inserm U835-Upres EA2311, Biochimie Pharmaceutique, Rennes University, 2 av. du prof. Léon Bernard, 35000 Rennes, France
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29
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Hirvonen JJ. The use of molecular methods for the detection and identification of methicillin-resistant Staphylococcus aureus. Biomark Med 2015; 8:1115-25. [PMID: 25402581 DOI: 10.2217/bmm.14.60] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen in many hospitals and long-term care facilities as well as in the community. To limit the spread of MRSA, early detection and proper treatment are essential. Because conventional culture as gold standard is time consuming, new techniques such as PCR-based and hybridization assays have emerged for the rapid detection of MRSA. This review will focus on the currently available molecular-based assays and on their utility and performance for detection of S. aureus, of its virulence factors and of the markers for acquired resistance.
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Sassi M, Augagneur Y, Mauro T, Ivain L, Chabelskaya S, Hallier M, Sallou O, Felden B. SRD: a Staphylococcus regulatory RNA database. RNA (NEW YORK, N.Y.) 2015; 21:1005-17. [PMID: 25805861 PMCID: PMC4408781 DOI: 10.1261/rna.049346.114] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 02/16/2015] [Indexed: 05/06/2023]
Abstract
An overflow of regulatory RNAs (sRNAs) was identified in a wide range of bacteria. We designed and implemented a new resource for the hundreds of sRNAs identified in Staphylococci, with primary focus on the human pathogen Staphylococcus aureus. The "Staphylococcal Regulatory RNA Database" (SRD, http://srd.genouest.org/) compiled all published data in a single interface including genetic locations, sequences and other features. SRD proposes novel and simplified identifiers for Staphylococcal regulatory RNAs (srn) based on the sRNA's genetic location in S. aureus strain N315 which served as a reference. From a set of 894 sequences and after an in-depth cleaning, SRD provides a list of 575 srn exempt of redundant sequences. For each sRNA, their experimental support(s) is provided, allowing the user to individually assess their validity and significance. RNA-seq analysis performed on strains N315, NCTC8325, and Newman allowed us to provide further details, upgrade the initial annotation, and identified 159 RNA-seq independent transcribed sRNAs. The lists of 575 and 159 sRNAs sequences were used to predict the number and location of srns in 18 S. aureus strains and 10 other Staphylococci. A comparison of the srn contents within 32 Staphylococcal genomes revealed a poor conservation between species. In addition, sRNA structure predictions obtained with MFold are accessible. A BLAST server and the intaRNA program, which is dedicated to target prediction, were implemented. SRD is the first sRNA database centered on a genus; it is a user-friendly and scalable device with the possibility to submit new sequences that should spread in the literature.
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Affiliation(s)
- Mohamed Sassi
- Inserm U835 Biochimie Pharmaceutique, Rennes University, 35043 Rennes, France
| | - Yoann Augagneur
- Inserm U835 Biochimie Pharmaceutique, Rennes University, 35043 Rennes, France
| | - Tony Mauro
- Inserm U835 Biochimie Pharmaceutique, Rennes University, 35043 Rennes, France
| | - Lorraine Ivain
- Inserm U835 Biochimie Pharmaceutique, Rennes University, 35043 Rennes, France
| | | | - Marc Hallier
- Inserm U835 Biochimie Pharmaceutique, Rennes University, 35043 Rennes, France
| | - Olivier Sallou
- Institut de Recherche en Informatique et Systèmes Aléatoires, Rennes University, 35043 Rennes, France
| | - Brice Felden
- Inserm U835 Biochimie Pharmaceutique, Rennes University, 35043 Rennes, France
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31
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Durmuş S, Çakır T, Özgür A, Guthke R. A review on computational systems biology of pathogen-host interactions. Front Microbiol 2015; 6:235. [PMID: 25914674 PMCID: PMC4391036 DOI: 10.3389/fmicb.2015.00235] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 03/10/2015] [Indexed: 12/27/2022] Open
Abstract
Pathogens manipulate the cellular mechanisms of host organisms via pathogen-host interactions (PHIs) in order to take advantage of the capabilities of host cells, leading to infections. The crucial role of these interspecies molecular interactions in initiating and sustaining infections necessitates a thorough understanding of the corresponding mechanisms. Unlike the traditional approach of considering the host or pathogen separately, a systems-level approach, considering the PHI system as a whole is indispensable to elucidate the mechanisms of infection. Following the technological advances in the post-genomic era, PHI data have been produced in large-scale within the last decade. Systems biology-based methods for the inference and analysis of PHI regulatory, metabolic, and protein-protein networks to shed light on infection mechanisms are gaining increasing demand thanks to the availability of omics data. The knowledge derived from the PHIs may largely contribute to the identification of new and more efficient therapeutics to prevent or cure infections. There are recent efforts for the detailed documentation of these experimentally verified PHI data through Web-based databases. Despite these advances in data archiving, there are still large amounts of PHI data in the biomedical literature yet to be discovered, and novel text mining methods are in development to unearth such hidden data. Here, we review a collection of recent studies on computational systems biology of PHIs with a special focus on the methods for the inference and analysis of PHI networks, covering also the Web-based databases and text-mining efforts to unravel the data hidden in the literature.
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Affiliation(s)
- Saliha Durmuş
- Computational Systems Biology Group, Department of Bioengineering, Gebze Technical University, KocaeliTurkey
| | - Tunahan Çakır
- Computational Systems Biology Group, Department of Bioengineering, Gebze Technical University, KocaeliTurkey
| | - Arzucan Özgür
- Department of Computer Engineering, Boǧaziçi University, IstanbulTurkey
| | - Reinhard Guthke
- Leibniz Institute for Natural Product Research and Infection Biology – Hans-Knoell-Institute, JenaGermany
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Proctor RA, Kriegeskorte A, Kahl BC, Becker K, Löffler B, Peters G. Staphylococcus aureus Small Colony Variants (SCVs): a road map for the metabolic pathways involved in persistent infections. Front Cell Infect Microbiol 2014; 4:99. [PMID: 25120957 PMCID: PMC4112797 DOI: 10.3389/fcimb.2014.00099] [Citation(s) in RCA: 154] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 07/07/2014] [Indexed: 12/31/2022] Open
Abstract
Persistent and relapsing infections, despite apparently adequate antibiotic therapy, occur frequently with many pathogens, but it is an especially prominent problem with Staphylococcus aureus infections. For the purposes of this review, persistence will encompass both of the concepts of long term survival within the host, including colonization, and the concept of resisting antibiotic therapy even when susceptible in the clinical microbiology laboratory. Over the past two decades, the mechanisms whereby bacteria achieve persistence are slowly being unraveled. S. aureus small colony variants (SCVs) are linked to chronic, recurrent, and antibiotic-resistant infections, and the study of SCVs has contributed significantly to understanding of persistence. In our earlier work, defects in electron transport and thymidylate biosynthesis were linked to the development of the SCV phenotype (reviewed in 2006), thus this work will be discussed only briefly. Since 2006, it has been found that persistent organisms including SCVs are part of the normal life cycle of bacteria, and often they arise in response to harsh conditions, e.g., antibiotics, starvation, host cationic peptides. Many of the changes found in these early SCVs have provided a map for the discovery mechanisms (pathways) for the development of persistent organisms. For example, changes in RNA processing, stringent response, toxin-antitoxin, ribosome protein L6 (RplF), and cold shock protein B (CspB) found in SCVs are also found in other persisters. In addition, many classic persister organisms also show slow growth, hence SCVs. Recent work on S. aureus USA300 has elucidated the impact of aerobic expression of arginine deiminase genes on its ability to chronically colonize the skin and survive in abscesses. S. aureus SCVs also express arginine deiminase genes aerobically as well. Thus, many pathways found activated in electron transport type of SCVs are also increased in persisters that have intact electron transport. Many of these changes in metabolism result in slow growth; hence, small colonies are formed. Another common theme is that slow growth is also associated with reduced expression of virulence factors and enhanced uptake/survival within host cells. These adaptations to survive within the host are rooted in responses that were required for organisms to survive in a harsh environment long before they were mammals on the earth.
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Affiliation(s)
- Richard A Proctor
- Departments of Medical Microbiology/Immunology and Medicine, University of Wisconsin School of Medicine and Public Health Madison, WI, USA
| | - André Kriegeskorte
- Institute of Medical Microbiology, University Hospital, Münster Münster, Germany
| | - Barbara C Kahl
- Institute of Medical Microbiology, University Hospital, Münster Münster, Germany
| | - Karsten Becker
- Institute of Medical Microbiology, University Hospital, Münster Münster, Germany
| | - Bettina Löffler
- Institute of Medical Microbiology, University Hospital, Münster Münster, Germany
| | - Georg Peters
- Institute of Medical Microbiology, University Hospital, Münster Münster, Germany
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33
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Novel aspects of RNA regulation inStaphylococcus aureus. FEBS Lett 2014; 588:2523-9. [DOI: 10.1016/j.febslet.2014.05.037] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 05/16/2014] [Accepted: 05/19/2014] [Indexed: 11/24/2022]
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Dual toxic-peptide-coding Staphylococcus aureus RNA under antisense regulation targets host cells and bacterial rivals unequally. Cell Rep 2014; 7:424-435. [PMID: 24703849 DOI: 10.1016/j.celrep.2014.03.012] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 02/05/2014] [Accepted: 03/05/2014] [Indexed: 12/20/2022] Open
Abstract
Produced from the pathogenicity islands of Staphylococcus aureus clinical isolates, stable SprG1 RNA encodes two peptides from a single internal reading frame. These two peptides accumulate at the membrane, and inducing their expression triggers S. aureus death. Replacement of the two initiation codons by termination signals reverses this toxicity. During growth, cis-antisense RNA SprF1 is expressed, preventing mortality by reducing SprG1 RNA and peptide levels. The peptides are secreted extracellularly, where they lyse human host erythrocytes, a process performed more efficiently by the longer peptide. The two peptides also inactivate Gram-negative and -positive bacteria, with the shorter peptide more effective against S. aureus rivals. Two peptides are secreted from an individual RNA containing two functional initiation codons. Thus, we present an unconventional type I toxin-antitoxin system expressed from a human pathogen producing two hemolytic and antibacterial peptides from a dual-coding RNA, negatively regulated by a dual-acting antisense RNA.
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35
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Eyraud A, Tattevin P, Chabelskaya S, Felden B. A small RNA controls a protein regulator involved in antibiotic resistance in Staphylococcus aureus. Nucleic Acids Res 2014; 42:4892-905. [PMID: 24557948 PMCID: PMC4005690 DOI: 10.1093/nar/gku149] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The emergence of Staphylococcus aureus strains that are resistant to glycopeptides has led to alarming scenarios where serious staphylococcal infections cannot be treated. The bacterium expresses many small regulatory RNAs (sRNAs) that have unknown biological functions for the most part. Here we show that an S. aureus sRNA, SprX (alias RsaOR), shapes bacterial resistance to glycopeptides, the invaluable treatments for Methicillin-resistant staphylococcal infections. Modifying SprX expression levels influences Vancomycin and Teicoplanin glycopeptide resistance. Comparative proteomic studies have identified that SprX specifically downregulates stage V sporulation protein G, SpoVG. SpoVG is produced from the yabJ-spoVG operon and contributes to S. aureus glycopeptide resistance. SprX negatively regulates SpoVG expression by direct antisense pairings at the internal translation initiation signals of the second operon gene, without modifying bicistronic mRNA expression levels or affecting YabJ translation. The SprX and yabJ-spoVG mRNA domains involved in the interaction have been identified, highlighting the importance of a CU-rich loop of SprX in the control of SpoVG expression. We have shown that SpoVG might not be the unique SprX target involved in the glycopeptide resistance and demonstrated that the regulation of glycopeptide sensitivity involves the CU-rich domain of SprX. Here we report the case of a sRNA influencing antibiotic resistance of a major human pathogen.
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Affiliation(s)
- Alex Eyraud
- Université de Rennes I, Inserm U835, Upres EA2311, Biochimie Pharmaceutique, 2 avenue du Prof. Léon Bernard, 35043 Rennes, France
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36
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Chabelskaya S, Bordeau V, Felden B. Dual RNA regulatory control of a Staphylococcus aureus virulence factor. Nucleic Acids Res 2014; 42:4847-58. [PMID: 24510101 PMCID: PMC4005698 DOI: 10.1093/nar/gku119] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In pathogens, the accurate programming of virulence gene expression is essential for infection. It is achieved by sophisticated arrays of regulatory proteins and ribonucleic acids (sRNAs), but in many cases their contributions and connections are not yet known. Based on genetic, biochemical and structural evidence, we report that the expression pattern of a Staphylococcus aureus host immune evasion protein is enabled by the collaborative actions of RNAIII and small pathogenicity island RNA D (SprD). Their combined expression profiles during bacterial growth permit early and transient synthesis of Sbi to avoid host immune responses. Together, these two sRNAs use antisense mechanisms to monitor Sbi expression at the translational level. Deletion analysis combined with structural analysis of RNAIII in complex with its novel messenger RNA (mRNA) target indicate that three distant RNAIII domains interact with distinct sites of the sbi mRNA and that two locations are deep in the sbi coding region. Through distinct domains, RNAIII lowers production of two proteins required for avoiding innate host immunity, staphylococcal protein A and Sbi. Toeprints and in vivo mutational analysis reveal a novel regulatory module within RNAIII essential for attenuation of Sbi translation. The sophisticated translational control of mRNA by two differentially expressed sRNAs ensures supervision of host immune escape by a major pathogen.
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Affiliation(s)
- Svetlana Chabelskaya
- Université de Rennes 1, Inserm U835-UPRES EA 2311, Biochimie Pharmaceutique, 2 avenue du Prof. Léon Bernard, 35043 Rennes, France
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