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Hallier M, Bronsard J, Dréano S, Sassi M, Cattoir V, Felden B, Augagneur Y. RNAIII is linked with the pentose phosphate pathway through the activation of RpiRc in Staphylococcus aureus. mSphere 2024; 9:e0034823. [PMID: 38591898 DOI: 10.1128/msphere.00348-23] [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: 06/29/2023] [Accepted: 03/18/2024] [Indexed: 04/10/2024] Open
Abstract
Staphylococcus aureus RNAIII is a dual-function regulatory RNA that controls the expression of multiple virulence genes and especially the transition from adhesion to the production of exotoxins. However, its contribution to S. aureus central metabolism remains unclear. Using MS2-affinity purification coupled with RNA sequencing, we uncovered more than 50 novel RNAIII-mRNA interactions. Among them, we demonstrate that RNAIII is a major activator of the rpiRc gene, encoding a regulator of the pentose phosphate pathway (PPP). RNAIII binds the 5' UTR of rpiRc mRNA to favor ribosome loading, leading to an increased expression of RpiRc and, subsequently, of two PPP enzymes. Finally, we show that RNAIII and RpiRc are involved in S. aureus fitness in media supplemented with various carbohydrate sources related to PPP and glycolysis. Collectively, our data depict an unprecedented phenotype associated with the RNAIII regulon, especially the direct implication of RNAIII in central metabolic activity modulation. These findings show that the contribution of RNAIII in Staphylococcus aureus adaptation goes far beyond what was initially reported. IMPORTANCE Staphylococcus aureus is a major human pathogen involved in acute and chronic infections. Highly recalcitrant to antibiotic treatment, persistent infections are mostly associated with the loss of RNAIII expression, a master RNA regulator responsible for the switch from colonization to infection. Here, we used the MS2 affinity purification coupled with RNA sequencing approach to identify novel mRNA targets of RNAIII and uncover novel functions. We demonstrate that RNAIII is an activator of the expression of genes involved in the pentose phosphate pathway and is implicated in the adjustment of bacterial fitness as a function of carbohydrate sources. Taken together, our results demonstrate an unprecedented role of RNAIII that goes beyond the knowledge gained so far and contributes to a better understanding of the role of RNAIII in bacterial adaptation expression and the coordination of a complex regulatory network.
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Affiliation(s)
- Marc Hallier
- QCPS (Quality Control in Protein Synthesis), IGDR UMR CNRS 6290, Université de Rennes 1, Rennes, France
- BRM (Bacterial Regulatory RNAs and Medicine), UMR_S 1230, Université de Rennes 1, Rennes, France
| | - Julie Bronsard
- BRM (Bacterial Regulatory RNAs and Medicine), UMR_S 1230, Université de Rennes 1, Rennes, France
| | - Stéphane Dréano
- Molecular Bases of Tumorigenesis: VHL Disease Team, CNRS UMR 6290 IGDR, BIOSIT, Université de Rennes 1, Rennes, France
| | - Mohamed Sassi
- BRM (Bacterial Regulatory RNAs and Medicine), UMR_S 1230, Université de Rennes 1, Rennes, France
| | - Vincent Cattoir
- BRM (Bacterial Regulatory RNAs and Medicine), UMR_S 1230, Université de Rennes 1, Rennes, France
| | - Brice Felden
- BRM (Bacterial Regulatory RNAs and Medicine), UMR_S 1230, Université de Rennes 1, Rennes, France
| | - Yoann Augagneur
- BRM (Bacterial Regulatory RNAs and Medicine), UMR_S 1230, Université de Rennes 1, Rennes, France
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2
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Schnoor SB, Neubauer P, Gimpel M. Recent insights into the world of dual-function bacterial sRNAs. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023:e1824. [PMID: 38039556 DOI: 10.1002/wrna.1824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/20/2023] [Accepted: 10/23/2023] [Indexed: 12/03/2023]
Abstract
Dual-function sRNAs refer to a small subgroup of small regulatory RNAs that merges base-pairing properties of antisense RNAs with peptide-encoding properties of mRNA. Both functions can be part of either same or in another metabolic pathway. Here, we want to update the knowledge of to the already known dual-function sRNAs and review the six new sRNAs found since 2017 regarding their structure, functional mechanisms, evolutionary conservation, and role in the regulation of distinct biological/physiological processes. The increasing identification of dual-function sRNAs through bioinformatics approaches, RNomics and RNA-sequencing and the associated increase in regulatory understanding will likely continue to increase at the same rate in the future. This may improve our understanding of the physiology, virulence and resistance of bacteria, as well as enable their use in technical applications. This article is categorized under: Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs.
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Affiliation(s)
| | - Peter Neubauer
- Department of Bioprocess Engineering, Technische Universitat Berlin, Berlin, Germany
| | - Matthias Gimpel
- Department of Bioprocess Engineering, Technische Universitat Berlin, Berlin, Germany
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3
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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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4
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Li Y, Ma X, Yue Y, Zhang K, Cheng K, Feng Q, Ma N, Liang J, Zhang T, Zhang L, Chen Z, Wang X, Ren L, Zhao X, Nie G. Rapid Surface Display of mRNA Antigens by Bacteria-Derived Outer Membrane Vesicles for a Personalized Tumor Vaccine. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2109984. [PMID: 35315546 DOI: 10.1002/adma.202109984] [Citation(s) in RCA: 80] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 02/21/2022] [Indexed: 06/14/2023]
Abstract
Therapeutic mRNA vaccination is an attractive approach to trigger antitumor immunity. However, the mRNA delivery technology for customized tumor vaccine is still limited. In this work, bacteria-derived outer membrane vesicles (OMVs) are employed as an mRNA delivery platform by genetically engineering with surface decoration of RNA binding protein, L7Ae, and lysosomal escape protein, listeriolysin O (OMV-LL). OMV-LL can rapidly adsorb box C/D sequence-labelled mRNA antigens through L7Ae binding (OMV-LL-mRNA) and deliver them into dendritic cells (DCs), following by the cross-presentation via listeriolysin O-mediated endosomal escape. OMV-LL-mRNA significantly inhibits melanoma progression and elicits 37.5% complete regression in a colon cancer model. OMV-LL-mRNA induces a long-term immune memory and protects the mice from tumor challenge after 60 days. In summary, this platform provides a delivery technology distinct from lipid nanoparticles (LNPs) for personalized mRNA tumor vaccination, and with a "Plug-and-Display" strategy that enables its versatile application in mRNA vaccines.
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Affiliation(s)
- Yao Li
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, 11 Beiyitiao, Zhongguancun, Beijing, 100190, China
- Department of Biomaterials, Key Laboratory of Biomedical Engineering of Fujian Province, College of Materials, Xiamen University, Xiamen, Fujian, 361005, China
| | - Xiaotu Ma
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, 11 Beiyitiao, Zhongguancun, Beijing, 100190, China
| | - Yale Yue
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, 11 Beiyitiao, Zhongguancun, Beijing, 100190, China
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan, 450001, China
| | - Kaiyue Zhang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, 11 Beiyitiao, Zhongguancun, Beijing, 100190, China
| | - Keman Cheng
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, 11 Beiyitiao, Zhongguancun, Beijing, 100190, China
| | - Qingqing Feng
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, 11 Beiyitiao, Zhongguancun, Beijing, 100190, China
| | - Nana Ma
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, 11 Beiyitiao, Zhongguancun, Beijing, 100190, China
| | - Jie Liang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, 11 Beiyitiao, Zhongguancun, Beijing, 100190, China
| | - Tianjiao Zhang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, 11 Beiyitiao, Zhongguancun, Beijing, 100190, China
| | - Lizhuo Zhang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, 11 Beiyitiao, Zhongguancun, Beijing, 100190, China
| | - Zhiqiang Chen
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, 11 Beiyitiao, Zhongguancun, Beijing, 100190, China
| | - Xinwei Wang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, 11 Beiyitiao, Zhongguancun, Beijing, 100190, China
| | - Lei Ren
- Department of Biomaterials, Key Laboratory of Biomedical Engineering of Fujian Province, College of Materials, Xiamen University, Xiamen, Fujian, 361005, China
| | - Xiao Zhao
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, 11 Beiyitiao, Zhongguancun, Beijing, 100190, China
- IGDB-NCNST Joint Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Xiamen, Beijing, 100101, China
| | - Guangjun Nie
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, 11 Beiyitiao, Zhongguancun, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Xiamen, Beijing, 100049, China
- The GBA National Institute for Nanotechnology Innovation, Guangdong, 510700, China
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5
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Desouky SE, Abu-Elghait M, Fayed EA, Selim S, Yousuf B, Igarashi Y, Abdel-Wahab BA, Mohammed Alsuhaibani A, Sonomoto K, Nakayama J. Secondary Metabolites of Actinomycetales as Potent Quorum Sensing Inhibitors Targeting Gram-Positive Pathogens: In Vitro and In Silico Study. Metabolites 2022; 12:metabo12030246. [PMID: 35323689 PMCID: PMC8955454 DOI: 10.3390/metabo12030246] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 03/07/2022] [Accepted: 03/08/2022] [Indexed: 02/07/2023] Open
Abstract
Anti-virulence agents are non-bacteriostatic and non-bactericidal emerging therapeutic options which hamper the production of virulence factors in pathogenic flora. In Staphylococcus aureus and Enterococcus faecalis, regulation of virulence genes’ expression occurs through the cyclic peptide-mediated accessory gene regulator (agr) and its ortholog fsr quorum sensing systems, respectively. In the present study, we screened a set of 54 actinomycetales secondary metabolites as novel anti-virulence compounds targeting quorum sensing system of the Gram-positive bacteria. The results indicated that four compounds, Phenalinolactones A–D, BU–4664LMe, 4,5-dehydrogeldamycin, and Questinomycin A, potentially inhibit the agr quorum sensing system and hemolytic activity of S. aureus. On the other hand, Decatromicin A and B, Okilactomycin, Rishirilide A, Abyssomicin I, and Rebeccamycin selectively blocked the fsr quorum sensing system and the gelatinase production in E. faecalis at sub-lethal concentrations. Interestingly, Synerazol uniquely showed the capability to inhibit both fsr and agr quorum sensing systems. Further, in silico molecular docking studies were performed which provided closer insights into the mode of action of these compounds and proposed that the inhibitory activity of these compounds could be attributed to their potential ability to bind to the ATP-active site of S. aureus AgrA. Taken together, our study highlights the potential of actinomycetales secondary metabolites with diverse structures as anti-virulence quorum sensing inhibitors.
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Affiliation(s)
- Said E. Desouky
- Department of Botany and Microbiology, Faculty of Science, Al-Azhar University, Cairo 11884, Egypt;
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan; (B.Y.); (K.S.); (J.N.)
- Correspondence:
| | - Mohammed Abu-Elghait
- Department of Botany and Microbiology, Faculty of Science, Al-Azhar University, Cairo 11884, Egypt;
| | - Eman A. Fayed
- Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy (Girls), Al-Azhar University, Cairo 11754, Egypt;
| | - Samy Selim
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka 72341, Saudi Arabia;
| | - Basit Yousuf
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan; (B.Y.); (K.S.); (J.N.)
| | - Yasuhiro Igarashi
- Biotechnology Research Center, Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan;
| | - Basel A. Abdel-Wahab
- Department of Medical Pharmacology, College of Medicine, Assiut University, Assiut 7111, Egypt;
- Department of Pharmacology, College of Pharmacy, Najran University, Najran 1988, Saudi Arabia
| | - Amnah Mohammed Alsuhaibani
- Department of Physical Sport Science, College of Education, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia;
| | - Kenji Sonomoto
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan; (B.Y.); (K.S.); (J.N.)
| | - Jiro Nakayama
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan; (B.Y.); (K.S.); (J.N.)
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6
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Felden B, Augagneur Y. Diversity and Versatility in Small RNA-Mediated Regulation in Bacterial Pathogens. Front Microbiol 2021; 12:719977. [PMID: 34447363 PMCID: PMC8383071 DOI: 10.3389/fmicb.2021.719977] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 07/20/2021] [Indexed: 11/13/2022] Open
Abstract
Bacterial gene expression is under the control of a large set of molecules acting at multiple levels. In addition to the transcription factors (TFs) already known to be involved in global regulation of gene expression, small regulatory RNAs (sRNAs) are emerging as major players in gene regulatory networks, where they allow environmental adaptation and fitness. Developments in high-throughput screening have enabled their detection in the entire bacterial kingdom. These sRNAs influence a plethora of biological processes, including but not limited to outer membrane synthesis, metabolism, TF regulation, transcription termination, virulence, and antibiotic resistance and persistence. Almost always noncoding, they regulate target genes at the post-transcriptional level, usually through base-pair interactions with mRNAs, alone or with the help of dedicated chaperones. There is growing evidence that sRNA-mediated mechanisms of actions are far more diverse than initially thought, and that they go beyond the so-called cis- and trans-encoded classifications. These molecules can be derived and processed from 5' untranslated regions (UTRs), coding or non-coding sequences, and even from 3' UTRs. They usually act within the bacterial cytoplasm, but recent studies showed sRNAs in extracellular vesicles, where they influence host cell interactions. In this review, we highlight the various functions of sRNAs in bacterial pathogens, and focus on the increasing examples of widely diverse regulatory mechanisms that might compel us to reconsider what constitute the sRNA.
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Affiliation(s)
- Brice Felden
- Inserm, Bacterial Regulatory RNAs and Medicine (BRM) - UMR_S 1230, Rennes, France
| | - Yoann Augagneur
- Inserm, Bacterial Regulatory RNAs and Medicine (BRM) - UMR_S 1230, Rennes, France
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7
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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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8
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Butrico CE, Cassat JE. Quorum Sensing and Toxin Production in Staphylococcus aureus Osteomyelitis: Pathogenesis and Paradox. Toxins (Basel) 2020; 12:toxins12080516. [PMID: 32806558 PMCID: PMC7471978 DOI: 10.3390/toxins12080516] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 08/04/2020] [Accepted: 08/10/2020] [Indexed: 01/18/2023] Open
Abstract
Staphylococcus aureus is a Gram-positive pathogen capable of infecting nearly every vertebrate organ. Among these tissues, invasive infection of bone (osteomyelitis) is particularly common and induces high morbidity. Treatment of osteomyelitis is notoriously difficult and often requires debridement of diseased bone in conjunction with prolonged antibiotic treatment to resolve infection. During osteomyelitis, S. aureus forms characteristic multicellular microcolonies in distinct niches within bone. Virulence and metabolic responses within these multicellular microcolonies are coordinated, in part, by quorum sensing via the accessory gene regulator (agr) locus, which allows staphylococcal populations to produce toxins and adapt in response to bacterial density. During osteomyelitis, the Agr system significantly contributes to dysregulation of skeletal homeostasis and disease severity but may also paradoxically inhibit persistence in the host. Moreover, the Agr system is subject to complex crosstalk with other S. aureus regulatory systems, including SaeRS and SrrAB, which can significantly impact the progression of osteomyelitis. The objective of this review is to highlight Agr regulation, its implications on toxin production, factors that affect Agr activation, and the potential paradoxical influences of Agr regulation on disease progression during osteomyelitis.
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Affiliation(s)
- Casey E. Butrico
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA;
| | - James E. Cassat
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA;
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation (VI4), Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Correspondence: ; Tel.: +1-615-936-6494
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9
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Transcriptional regulation of virulence factors Hla and phenol-soluble modulins α by AraC-type regulator Rbf in Staphylococcus aureus. Int J Med Microbiol 2020; 310:151436. [PMID: 32654771 DOI: 10.1016/j.ijmm.2020.151436] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 05/25/2020] [Accepted: 06/14/2020] [Indexed: 12/15/2022] Open
Abstract
Staphylococcus aureus is a gram-positive pathogenic bacterium and is capable of secreting numerous toxins interfering directly with the host to cause acute infections. Rbf, a transcriptional regulator of AraC/XylS family, has been reported to promote biofilm formation in polysaccharide intercellular adhesion (PIA) mediated manner to cause chronic infections. In this study, we revealed the new virulence-mediated role of Rbf that can negatively regulate the hemolytic activity. Furthermore, Rbf can specifically bind to the hla and psmα promoters to repress their expression, resulting in significantly decreased production of phenol-soluble modulins α (PSMα) and alpha-toxin. Accordingly, the rbf mutant strain exhibited the increased pathogenicity compared to the wild-type (WT) strain in a mouse subcutaneous abscess model, representing a type of acute infection by S. aureus. Collectively, our results provide a novel insight into the virulence regulation and acute infections mediated by Rbf in S. aureus.
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10
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Abstract
Quorum sensing is a vital property of bacteria that enables community-wide coordination of collective behaviors. A key example of such a behavior is biofilm formation, in which groups of bacteria invest in synthesizing a protective, joint extracellular matrix. Quorum sensing involves the production, release, and subsequent detection of extracellular signaling molecules called autoinducers. The architecture of quorum-sensing signal transduction pathways is highly variable among different species of bacteria, but frequently involves posttranscriptional regulation carried out by small regulatory RNA molecules. This review illustrates the diverse roles small trans-acting regulatory RNAs can play, from constituting a network's core to auxiliary roles in adjusting the rate of autoinducer synthesis, mediating cross talk among different parts of a network, or integrating different regulatory inputs to trigger appropriate changes in gene expression. The emphasis is on describing how the study of small RNA-based regulation in quorum sensing and biofilm formation has uncovered new general properties or expanded our understanding of bacterial riboregulation.
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11
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Jin Z, Jiang Q, Fang B, Sun B. The ArlR-MgrA regulatory cascade regulates PIA-dependent and protein-mediated biofilm formation in Rbf-dependent and Rbf-independent pathways. Int J Med Microbiol 2018; 309:85-96. [PMID: 30606691 DOI: 10.1016/j.ijmm.2018.12.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 12/01/2018] [Accepted: 12/28/2018] [Indexed: 12/11/2022] Open
Abstract
The two-component system response regulator ArlR and the global regulator MgrA in Staphylococcus aureus participated in numerous biological processes including biofilm formation inhibition. Previous studies have shown that these two regulators could function as a regulatory cascade. Rbf is a positive regulator of biofilm formation enhancing the production of PIA (polysaccharide intercellular adhesin). Here we have demonstrated that both ArlR and MgrA can directly bind to the promoter of rbf and repress its expression. ArlR and MgrA can also directly bind to the promoter of ica operon and enhance the expression of icaA and PIA production, revealing that the ArlR-MgrA regulatory cascade controls PIA-dependent biofilm formation. In addition, we have found that Rbf can directly bind to the aur promoter and repress the expression of aur, which encodes a protease initiating a protease cascade to inhibit protein-mediated biofilm formation. Moreover, our data indicate that the ArlR-MgrA regulatory cascade can promote the expression of aur by directly binding to its promoter and inhibit protein-mediated biofilm formation. These findings shed light on the molecular mechanisms of both PIA-dependent and protein-mediated biofilm formation modulated by the ArlR-MgrA regulatory cascade and the new role of Rbf in protein-mediated biofilm formation, and broaden our understanding of the biofilm formation regulation in S. aureus.
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Affiliation(s)
- Zeyu Jin
- CAS Key Laboratory of Innate Immunity and Chronic Disease and School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui, 230027, China
| | - Qiu Jiang
- CAS Key Laboratory of Innate Immunity and Chronic Disease and School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui, 230027, China
| | - Bo Fang
- CAS Key Laboratory of Innate Immunity and Chronic Disease and School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui, 230027, China
| | - Baolin Sun
- CAS Key Laboratory of Innate Immunity and Chronic Disease and School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui, 230027, China; Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230027, China.
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12
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Raina M, King A, Bianco C, Vanderpool CK. Dual-Function RNAs. Microbiol Spectr 2018; 6:10.1128/microbiolspec.RWR-0032-2018. [PMID: 30191807 PMCID: PMC6130917 DOI: 10.1128/microbiolspec.rwr-0032-2018] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Indexed: 12/30/2022] Open
Abstract
Bacteria are known to use RNA, either as mRNAs encoding proteins or as noncoding small RNAs (sRNAs), to regulate numerous biological processes. However, a few sRNAs have two functions: they act as base-pairing RNAs and encode a small protein with additional regulatory functions. Thus, these so called "dual-function" sRNAs can serve as both a riboregulator and an mRNA. In some cases, these two functions can act independently within the same pathway, while in other cases, the base-pairing function and protein function act in different pathways. Here, we discuss the five known dual-function sRNAs-SgrS from enteric species, RNAIII and Psm-mec from Staphylococcus aureus, Pel RNA from Streptococcus pyogenes, and SR1 from Bacillus subtilis-and review their mechanisms of action and roles in regulating diverse biological processes. We also discuss the prospect of finding additional dual-function sRNAs and future challenges in studying the overlap and competition between the functions.
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Affiliation(s)
- Medha Raina
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892
| | - Alisa King
- Department of Microbiology, University of Illinois, Urbana, IL 61801
| | - Colleen Bianco
- Department of Microbiology, University of Illinois, Urbana, IL 61801
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13
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Le Scornet A, Redder P. Post-transcriptional control of virulence gene expression in Staphylococcus aureus. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1862:734-741. [PMID: 29705591 DOI: 10.1016/j.bbagrm.2018.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 04/25/2018] [Accepted: 04/25/2018] [Indexed: 12/12/2022]
Abstract
Opportunistic pathogens have to be ready to change life-style whenever the occasion arises, and therefore need to keep tight control over the expression of their virulence factors. Doubly so for commensal bacteria, such as Staphylococcus aureus, which should avoid harming their hosts when they are in a state of peaceful co-existence. S. aureus carries very few sigma factors to help define the transcriptional programs, but instead uses a plethora of small RNA molecules and RNA-RNA interactions to regulate gene expression post-transcriptionally. The endoribonucleases RNase III and RNase Y contribute to this regulatory diversity, and provide a link to RNA-decay and intra-cellular spatiotemporal control of expression. In this review we describe some of these post-transcriptional mechanisms as well as some of the novel transcriptomic approaches that have been used to find and to study them.
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Affiliation(s)
- Alexandre Le Scornet
- LMGM, Centre de Biologie Integrative, Paul Sabatier University, 118, Route de Narbonne, 31062 Toulouse, France
| | - Peter Redder
- LMGM, Centre de Biologie Integrative, Paul Sabatier University, 118, Route de Narbonne, 31062 Toulouse, France.
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14
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Autoregulation and Virulence Control by the Toxin-Antitoxin System SavRS in Staphylococcus aureus. Infect Immun 2018; 86:IAI.00032-18. [PMID: 29440365 PMCID: PMC5913840 DOI: 10.1128/iai.00032-18] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 02/05/2018] [Indexed: 11/20/2022] Open
Abstract
Toxin-antitoxin (TA) systems play diverse physiological roles, such as plasmid maintenance, growth control, and persister cell formation, but their involvement in bacterial pathogenicity remains largely unknown. Here, we have identified a novel type II toxin-antitoxin system, SavRS, and revealed the molecular mechanisms of its autoregulation and virulence control in Staphylococcus aureus Electrophoretic mobility shift assay and isothermal titration calorimetry data indicated that the antitoxin SavR acted as the primary repressor bound to its own promoter, while the toxin SavS formed a complex with SavR to enhance the ability to bind to the operator site. DNase I footprinting assay identified the SavRS-binding site containing a short and long palindrome in the promoter region. Further, mutation and DNase I footprinting assay demonstrated that the two palindromes were crucial for DNA binding and transcriptional repression. More interestingly, genetic deletion of the savRS system led to the increased hemolytic activity and pathogenicity in a mouse subcutaneous abscess model. We further identified two virulence genes, hla and efb, by real-time quantitative reverse transcription-PCR and demonstrated that SavR and SavRS could directly bind to their promoter regions to repress virulence gene expression.
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15
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Small RNA-mediated regulation in bacteria: A growing palette of diverse mechanisms. Gene 2018; 656:60-72. [PMID: 29501814 DOI: 10.1016/j.gene.2018.02.068] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 02/19/2018] [Accepted: 02/27/2018] [Indexed: 11/23/2022]
Abstract
Small RNAs (sRNAs) in bacteria have evolved with diverse mechanisms to balance their target gene expression in response to changes in the environment. Accumulating studies on bacterial regulatory processes firmly established that sRNAs modulate their target gene expression generally at the posttranscriptional level. Identification of large number of sRNAs by advanced technologies, like deep sequencing, tilling microarray, indicates the existence of a plethora of distinctive sRNA-mediated regulatory mechanisms in bacteria. Types of the novel mechanisms are increasing with the discovery of new sRNAs. Complementary base pairing between sRNAs and target RNAs assisted by RNA chaperones like Hfq and ProQ, in many occasions, to regulate the cognate gene expression is prevalent in sRNA mechanisms. sRNAs, in most studied cases, can directly base pair with target mRNA to remodel its expression. Base pairing can happen either in the untranslated regions or in the coding regions of mRNA to activate/repress its translation. sRNAs also act as target mimic to titrate away different regulatory RNAs from its target. Other mechanism includes the sequestration of regulatory proteins, especially transcription factors, by sRNAs. Numerous sRNAs, following analogous mechanism, are widespread in bacteria, and thus, has drawn immense attention for the development of RNA-based technologies. Nevertheless, typical sRNA mechanisms are also discovered to be confined in some bacteria. Analysis of the sRNA mechanisms unravels their existence in both the single step processes and the complex regulatory networks with a global effect on cell physiology. This review deals with the diverse array of mechanisms, which sRNAs follow to maintain bacterial lifestyle.
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16
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Ivain L, Bordeau V, Eyraud A, Hallier M, Dreano S, Tattevin P, Felden B, Chabelskaya S. An in vivo reporter assay for sRNA-directed gene control in Gram-positive bacteria: identifying a novel sRNA target in Staphylococcus aureus. Nucleic Acids Res 2017; 45:4994-5007. [PMID: 28369640 PMCID: PMC5416835 DOI: 10.1093/nar/gkx190] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 03/11/2017] [Indexed: 12/15/2022] Open
Abstract
Bacterial small regulatory RNAs (sRNAs) play a major role in the regulation of various cellular functions. Most sRNAs interact with mRNA targets via an antisense mechanism, modifying their translation and/or degradation. Despite considerable progresses in discovering sRNAs in Gram-positive bacteria, their functions, for the most part, are unknown. This is mainly due to difficulties in identifying their targets. To aid in the identification of sRNA targets in Gram-positive bacteria, we set up an in vivo method for fast analysis of sRNA-mediated post-transcriptional control at the 5΄ regions of target mRNAs. The technology is based on the co-expression of an sRNA and a 5΄ sequence of an mRNA target fused to a green fluorescent protein (GFP) reporter. The system was challenged on Staphylococcus aureus, an opportunistic Gram-positive pathogen. We analyzed several established sRNA–mRNA interactions, and in addition, we identified the ecb mRNA as a novel target for SprX2 sRNA. Using our in vivo system in combination with in vitro experiments, we demonstrated that SprX2 uses an antisense mechanism to prevent ecb mRNA translation initiation. Furthermore, we used our reporter assay to validate sRNA regulations in other Gram-positive organisms, Bacillus subtilis and Listeria monocytogenes. Overall, our method is broadly applicable to challenge the predicted sRNA–mRNA interactions in Gram-positive bacteria.
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Affiliation(s)
- Lorraine Ivain
- Université de Rennes 1, Inserm U1230-UPRES EA 2311, Biochimie Pharmaceutique, Regulatory RNA and Medicine (RMM), 2 avenue du Prof. Léon Bernard, 35043 Rennes, France
| | - Valérie Bordeau
- Université de Rennes 1, Inserm U1230-UPRES EA 2311, Biochimie Pharmaceutique, Regulatory RNA and Medicine (RMM), 2 avenue du Prof. Léon Bernard, 35043 Rennes, France
| | - Alex Eyraud
- Université de Rennes 1, Inserm U1230-UPRES EA 2311, Biochimie Pharmaceutique, Regulatory RNA and Medicine (RMM), 2 avenue du Prof. Léon Bernard, 35043 Rennes, France
| | - Marc Hallier
- Université de Rennes 1, Inserm U1230-UPRES EA 2311, Biochimie Pharmaceutique, Regulatory RNA and Medicine (RMM), 2 avenue du Prof. Léon Bernard, 35043 Rennes, France
| | - Stéphane Dreano
- Université de Rennes 1, CNRS UMR 6290 IGDR, BIOSIT, Molecular Bases of Tumorigenesis: VHL Disease Team, 35043 Rennes, France
| | - Pierre Tattevin
- Université de Rennes 1, Inserm U1230-UPRES EA 2311, Biochimie Pharmaceutique, Regulatory RNA and Medicine (RMM), 2 avenue du Prof. Léon Bernard, 35043 Rennes, France
| | - Brice Felden
- Université de Rennes 1, Inserm U1230-UPRES EA 2311, Biochimie Pharmaceutique, Regulatory RNA and Medicine (RMM), 2 avenue du Prof. Léon Bernard, 35043 Rennes, France
| | - Svetlana Chabelskaya
- Université de Rennes 1, Inserm U1230-UPRES EA 2311, Biochimie Pharmaceutique, Regulatory RNA and Medicine (RMM), 2 avenue du Prof. Léon Bernard, 35043 Rennes, France
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17
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Ma R, Qiu S, Jiang Q, Sun H, Xue T, Cai G, Sun B. AI-2 quorum sensing negatively regulates rbf expression and biofilm formation in Staphylococcus aureus. Int J Med Microbiol 2017; 307:257-267. [PMID: 28416278 DOI: 10.1016/j.ijmm.2017.03.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus is an important pathogen that is capable of forming biofilms on biomaterial surfaces to cause biofilm-associated infections. Autoinducer 2 (AI-2), a universal language for interspecies communication, is involved in a variety of physiological activities, although its exact role in Gram-positive bacteria, especially in S. aureus, is not yet thoroughly characterized. Herein we demonstrate that inactivation of luxS, which encodes AI-2 synthase, resulted in increased biofilm formation and higher polysaccharide intercellular adhesion (PIA) production compared with the wild-type strain in S. aureus NCTC8325. The transcript level of rbf, a positive regulator of biofilm formation, was significantly increased in the luxS mutant. All of the parental phenotypes could be restored by genetic complementation and chemically synthesized 4,5-dihydroxy-2,3-pentanedione, the AI-2 precursor molecule, suggesting that AI-2 has a signaling function to regulate rbf transcription and biofilm formation in S. aureus. Phenotypic analysis revealed that the luxS rbf double mutant produced approximately the same amount of biofilms and PIA as the rbf mutant. In addition, real-time quantitative reverse transcription-PCR analysis showed that the icaA transcript level of the rbf mutant was similar to that of the luxS rbf double mutant. These findings demonstrate that the LuxS/AI-2 system regulates PIA-dependent biofilm formation via repression of rbf expression in S. aureus. Furthermore, we demonstrated that Rbf could bind to the sarX and rbf promoters to upregulate their expression.
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Affiliation(s)
- Ronghua Ma
- CAS Key Laboratory of Innate Immunity and Chronic Disease, University of Science and Technology of China, Hefei, Anhui 230027, China; School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Shuwan Qiu
- School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Qiu Jiang
- CAS Key Laboratory of Innate Immunity and Chronic Disease, University of Science and Technology of China, Hefei, Anhui 230027, China; School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Haipeng Sun
- CAS Key Laboratory of Innate Immunity and Chronic Disease, University of Science and Technology of China, Hefei, Anhui 230027, China; School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Ting Xue
- School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Gang Cai
- School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China; Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230027, China.
| | - Baolin Sun
- CAS Key Laboratory of Innate Immunity and Chronic Disease, University of Science and Technology of China, Hefei, Anhui 230027, China; School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China; Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230027, China.
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18
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Gimpel M, Brantl S. Dual-function small regulatory RNAs in bacteria. Mol Microbiol 2016; 103:387-397. [PMID: 27750368 DOI: 10.1111/mmi.13558] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 10/10/2016] [Accepted: 10/11/2016] [Indexed: 12/31/2022]
Abstract
Dual-function sRNAs are a subgroup of small regulatory RNAs that act on the one hand as base-pairing sRNAs to inhibit or activate target gene expression and on the other hand as peptide-encoding mRNAs that function either in the same or in another metabolic pathway. Here, we review and compare the five currently known and intensively characterized dual-function sRNAs with regard to their two functions, their biological role, their evolutionary conservation and their requirements for RNA chaperones. Furthermore, we summarize the data available on five potential dual-function sRNAs, whose base-pairing function is well established whereas the role of their encoded peptides has not yet been elucidated. In addition, we provide three examples for RNAs with more than one function that do not fall into the above-mentioned category. With the application of RNAseq, peptidomics and transcriptomics it can be expected that the number of dual-function sRNAs will considerably increase within the next years, thus enhancing our knowledge on the regulatory potential of these RNAs.
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Affiliation(s)
- Matthias Gimpel
- Biologisch-Pharmazeutische Fakultät, Lehrstuhl für Genetik, Friedrich-Schiller-Universität Jena, AG Bakteriengenetik, Philosophenweg 12, Jena, D-07743, Germany
| | - Sabine Brantl
- Biologisch-Pharmazeutische Fakultät, Lehrstuhl für Genetik, Friedrich-Schiller-Universität Jena, AG Bakteriengenetik, Philosophenweg 12, Jena, D-07743, Germany
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19
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Bronesky D, Wu Z, Marzi S, Walter P, Geissmann T, Moreau K, Vandenesch F, Caldelari I, Romby P. Staphylococcus aureus RNAIII and Its Regulon Link Quorum Sensing, Stress Responses, Metabolic Adaptation, and Regulation of Virulence Gene Expression. Annu Rev Microbiol 2016; 70:299-316. [PMID: 27482744 DOI: 10.1146/annurev-micro-102215-095708] [Citation(s) in RCA: 134] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Staphylococcus aureus RNAIII is one of the main intracellular effectors of the quorum-sensing system. It is a multifunctional RNA that encodes a small peptide, and its noncoding parts act as antisense RNAs to regulate the translation and/or the stability of mRNAs encoding transcriptional regulators, major virulence factors, and cell wall metabolism enzymes. In this review, we explain how regulatory proteins and RNAIII are embedded in complex regulatory circuits to express virulence factors in a dynamic and timely manner in response to stress and environmental and metabolic changes.
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Affiliation(s)
- Delphine Bronesky
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 67084 Strasbourg, France;
| | - Zongfu Wu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Stefano Marzi
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 67084 Strasbourg, France;
| | - Philippe Walter
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 67084 Strasbourg, France;
| | - Thomas Geissmann
- Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, Université de Lyon, INSERM U1111, CNRS UMR 5308, CIRI, 69008 Lyon, France
| | - Karen Moreau
- Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, Université de Lyon, INSERM U1111, CNRS UMR 5308, CIRI, 69008 Lyon, France
| | - François Vandenesch
- Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, Université de Lyon, INSERM U1111, CNRS UMR 5308, CIRI, 69008 Lyon, France
| | - Isabelle Caldelari
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 67084 Strasbourg, France;
| | - Pascale Romby
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 67084 Strasbourg, France;
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20
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Zhang S, Shu X, Sun B. SigmaB regulates ccrAB expression and SCCmec excision in methicillin-resistant Staphylococcus aureus. Int J Med Microbiol 2016; 306:406-14. [PMID: 27247101 DOI: 10.1016/j.ijmm.2016.05.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 04/11/2016] [Accepted: 05/12/2016] [Indexed: 10/21/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a worldwide pathogen that is resistant to practically the entire class of β-lactam antibiotics due to the presence of the mecA gene. The mecA gene is located on a large mobile genetic element referred to as staphylococcal cassette chromosome mec (SCCmec), and the excision and integration of SCCmec are mediated by the Ccr recombinase encoded by ccrAB or ccrC, which are also located on SCCmec. Previous studies have shown that the ccrAB genes are only expressed in a minority of cells and that their expression levels can be affected by certain environmental stimuli, but the molecular mechanisms controlling these phenotypes remain elusive. Here, we found that overexpression of SigB can dramatically enhance ccrA transcription and SCCmec excision in MRSA strain N315, revealing an important role for this alternative sigma factor in the lateral transfer of SCCmec. Further primer extension-blot analysis and 5'RACE (Rapid Amplification of cDNA Ends) indicated that an unrecognized SigB-dependent promoter region, which exists in certain SCCmec type II and IV strains, is responsible for the enhancement, and the ccrAB genes are in fact transcribed in a two-promoter pattern with a low activity of the SigB-dependent promoter under normal growth conditions.
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Affiliation(s)
- Shijie Zhang
- CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Xueqin Shu
- CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Baolin Sun
- CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China; Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230027, China.
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21
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Baldry M, Kitir B, Frøkiær H, Christensen SB, Taverne N, Meijerink M, Franzyk H, Olsen CA, Wells JM, Ingmer H. The agr Inhibitors Solonamide B and Analogues Alter Immune Responses to Staphylococccus aureus but Do Not Exhibit Adverse Effects on Immune Cell Functions. PLoS One 2016; 11:e0145618. [PMID: 26731096 PMCID: PMC4701192 DOI: 10.1371/journal.pone.0145618] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Accepted: 12/07/2015] [Indexed: 11/29/2022] Open
Abstract
Staphylococcus aureus infections are becoming increasingly difficult to treat due to antibiotic resistance with the community-associated methicillin-resistant S. aureus (CA-MRSA) strains such as USA300 being of particular concern. The inhibition of bacterial virulence has been proposed as an alternative approach to treat multi-drug resistant pathogens. One interesting anti-virulence target is the agr quorum-sensing system, which regulates virulence of CA-MRSA in response to agr-encoded autoinducing peptides. Agr regulation confines exotoxin production to the stationary growth phase with concomitant repression of surface-expressed adhesins. Solonamide B, a non-ribosomal depsipeptide of marine bacterial origin, was recently identified as a putative anti-virulence compound that markedly reduced expression of α-hemolysin and phenol-soluble modulins. To further strengthen solonamide anti-virulence candidacy, we report the chemical synthesis of solonamide analogues, investigation of structure–function relationships, and assessment of their potential to modulate immune cell functions. We found that structural differences between solonamide analogues confer significant differences in interference with agr, while immune cell activity and integrity is generally not affected. Furthermore, treatment of S. aureus with selected solonamides was found to only marginally influence the interaction with fibronectin and biofilm formation, thus addressing the concern that application of compounds inducing an agr-negative state may have adverse interactions with host factors in favor of host colonization.
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Affiliation(s)
- Mara Baldry
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Betül Kitir
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
- Center for Biopharmaceuticals, University of Copenhagen, Copenhagen, Denmark
| | - Hanne Frøkiær
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Simon B. Christensen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Nico Taverne
- Host Microbes Interactomics Group, Wageningen University, Wageningen, The Netherlands
| | - Marjolein Meijerink
- Host Microbes Interactomics Group, Wageningen University, Wageningen, The Netherlands
| | - Henrik Franzyk
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Christian A. Olsen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
- Center for Biopharmaceuticals, University of Copenhagen, Copenhagen, Denmark
| | - Jerry M. Wells
- Host Microbes Interactomics Group, Wageningen University, Wageningen, The Netherlands
| | - Hanne Ingmer
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
- * E-mail:
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22
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Yang Y, Sun H, Liu X, Wang M, Xue T, Sun B. Regulatory mechanism of the three-component system HptRSA in glucose-6-phosphate uptake in Staphylococcus aureus. Med Microbiol Immunol 2015; 205:241-53. [PMID: 26711125 DOI: 10.1007/s00430-015-0446-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 12/18/2015] [Indexed: 01/04/2023]
Abstract
Glucose-6-phosphate (G6P) is a common alternative carbon source for various bacteria, and its uptake usually relies on the hexose phosphate antiporter UhpT. In the human pathogenic bacterium Staphylococcus aureus, the ability to utilize different nutrients, particularly alternative carbon source uptake in glucose-limiting conditions, is essential for its fitness in the host environment during the infectious process. It has been reported that G6P uptake in S. aureus is regulated by the three-component system HptRSA. When G6P is provided as the only carbon source, HptRSA could sense extracellular G6P and activate uhpT expression to facilitate G6P utilization. However, the regulatory mechanism of HptRSA is still unclear. In this study, we further investigated the HptRSA system in S. aureus. First, we confirmed that HptRSA is necessary for the normal growth of this pathogen in chemically defined medium with G6P supplementation, and we discovered that HptRSA could exclusively sense extracellular G6P compared to the other organophosphates we tested. Next, using isothermal titration calorimetry, we found that HptA could bind to G6P, suggesting that it may be the G6P sensor. After that experiment, using an electrophoresis mobility shift assay, we verified that the response regulator HptR could directly bind to the uhpT promoter and identified a putative binding site from -67 to -96-bp. Subsequently, we created different point mutations in the putative binding site and revealed that the entire 30-bp sequence is essential for HptR regulation. In summary, we unveiled the regulatory mechanism of the HptRSA system in S. aureus, HptA most likely functions as the G6P sensor, and HptR could implement its regulatory function by directly binding to a conserved, approximately 30-bp sequence in the uhpT promoter.
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Affiliation(s)
- Yifan Yang
- School of Life Sciences, University of Science and Technology of China, Hefei, 230027, Anhui, China
| | - Haipeng Sun
- School of Life Sciences, University of Science and Technology of China, Hefei, 230027, Anhui, China
| | - Xiaoyu Liu
- School of Life Sciences, University of Science and Technology of China, Hefei, 230027, Anhui, China
| | - Mingxing Wang
- School of Life Sciences, University of Science and Technology of China, Hefei, 230027, Anhui, China
| | - Ting Xue
- School of Life Sciences, University of Science and Technology of China, Hefei, 230027, Anhui, China
| | - Baolin Sun
- School of Life Sciences, University of Science and Technology of China, Hefei, 230027, Anhui, China. .,CAS Key Laboratory of Innate Immunity and Chronic Disease, University of Science and Technology of China, Hefei, 230027, Anhui, China.
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23
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The Mechanisms of Virulence Regulation by Small Noncoding RNAs in Low GC Gram-Positive Pathogens. Int J Mol Sci 2015; 16:29797-814. [PMID: 26694351 PMCID: PMC4691137 DOI: 10.3390/ijms161226194] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 12/01/2015] [Accepted: 12/04/2015] [Indexed: 11/30/2022] Open
Abstract
The discovery of small noncoding regulatory RNAs (sRNAs) in bacteria has grown tremendously recently, giving new insights into gene regulation. The implementation of computational analysis and RNA sequencing has provided new tools to discover and analyze potential sRNAs. Small regulatory RNAs that act by base-pairing to target mRNAs have been found to be ubiquitous and are the most abundant class of post-transcriptional regulators in bacteria. The majority of sRNA studies has been limited to E. coli and other gram-negative bacteria. However, examples of sRNAs in gram-positive bacteria are still plentiful although the detailed gene regulation mechanisms behind them are not as well understood. Strict virulence control is critical for a pathogen’s survival and many sRNAs have been found to be involved in that process. This review outlines the targets and currently known mechanisms of trans-acting sRNAs involved in virulence regulation in various gram-positive pathogens. In addition, their shared characteristics such as CU interaction motifs, the role of Hfq, and involvement in two-component regulators, riboswitches, quorum sensing, or toxin/antitoxin systems are described.
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24
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RNAIII of the Staphylococcus aureus agr system activates global regulator MgrA by stabilizing mRNA. Proc Natl Acad Sci U S A 2015; 112:14036-41. [PMID: 26504242 DOI: 10.1073/pnas.1509251112] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
RNAIII, the effector of the agr quorum-sensing system, plays a key role in virulence gene regulation in Staphylococcus aureus, but how RNAIII transcriptionally regulates its downstream genes is not completely understood. Here, we show that RNAIII stabilizes mgrA mRNA, thereby increasing the production of MgrA, a global transcriptional regulator that affects the expression of many genes. The mgrA gene is transcribed from two promoters, P1 and P2, to produce two mRNA transcripts with long 5' UTR. Two adjacent regions of the mgrA mRNA UTR transcribed from the upstream P2 promoter, but not the P1 promoter, form a stable complex with two regions of RNAIII near the 5' and 3' ends. We further demonstrate that the interaction has several biological effects. We propose that MgrA can serve as an intermediary regulator through which agr exerts its regulatory function.
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Effect of negative pressure on growth, secretion and biofilm formation of Staphylococcus aureus. Antonie van Leeuwenhoek 2015; 108:907-17. [DOI: 10.1007/s10482-015-0545-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/20/2015] [Indexed: 02/07/2023]
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Modulation of ccrAB Expression and SCCmec Excision by an Inverted Repeat Element and SarS in Methicillin-Resistant Staphylococcus aureus. Antimicrob Agents Chemother 2015; 59:6223-32. [PMID: 26248371 DOI: 10.1128/aac.01041-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 07/18/2015] [Indexed: 01/06/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a notorious human pathogen that can cause a broad spectrum of infections. MRSA strains are resistant to almost the entire family of β-lactam antibiotics due to the acquisition of staphylococcal cassette chromosome mec (SCCmec). The chromosome cassette recombinases A and B, encoded by ccrAB genes located on SCCmec, play a key role in the excision of SCCmec. Studies have shown that ccrAB genes are expressed in only a minority of cells, suggesting the involvement of a subtle regulatory mechanism in ccrAB expression which has not been uncovered. Here, we found that an inverted repeat (IR) element, existing extensively and conservatively within the ccrAB promoter of different SCCmec types, played a repressive role in ccrAB expression and SCCmec excision in MRSA strain N315. Replacement of the IR sequence led to a significant increase in ccrAB expression and curing of SCCmec from strain N315 cells. In addition, we identified the transcriptional regulator SarS using DNA-affinity chromatography and further demonstrated that SarS can bind to the IR sequence and upregulate ccrAB expression and SCCmec excision. These findings reveal a molecular mechanism regulating ccrAB expression and SCCmec excision and may provide mechanic insights into the lateral transfer of SCCmec and spread of antibiotic resistance in S. aureus.
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Papenfort K, Vanderpool CK. Target activation by regulatory RNAs in bacteria. FEMS Microbiol Rev 2015; 39:362-78. [PMID: 25934124 DOI: 10.1093/femsre/fuv016] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/10/2015] [Indexed: 12/15/2022] Open
Abstract
Bacterial small regulatory RNAs (sRNAs) are commonly known to repress gene expression by base pairing to target mRNAs. In many cases, sRNAs base pair with and sequester mRNA ribosome-binding sites, resulting in translational repression and accelerated transcript decay. In contrast, a growing number of examples of translational activation and mRNA stabilization by sRNAs have now been documented. A given sRNA often employs a conserved region to interact with and regulate both repressed and activated targets. However, the mechanisms underlying activation differ substantially from repression. Base pairing resulting in target activation can involve sRNA interactions with the 5(') untranslated region (UTR), the coding sequence or the 3(') UTR of the target mRNAs. Frequently, the activities of protein factors such as cellular ribonucleases and the RNA chaperone Hfq are required for activation. Bacterial sRNAs, including those that function as activators, frequently control stress response pathways or virulence-associated functions required for immediate responses to changing environments. This review aims to summarize recent advances in knowledge regarding target mRNA activation by bacterial sRNAs, highlighting the molecular mechanisms and biological relevance of regulation.
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Affiliation(s)
- Kai Papenfort
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540, USA Department of Biology I, Ludwig-Maximilians-University Munich, 82152 Martinsried, Germany
| | - Carin K Vanderpool
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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Yan J, Liu Y, Gao Y, Dong J, Mu C, Li D, Yang G. RNAIII suppresses the expression of LtaS via acting as an antisense RNA inStaphylococcus aureus. J Basic Microbiol 2014; 55:255-61. [DOI: 10.1002/jobm.201400313] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 08/22/2014] [Indexed: 01/08/2023]
Affiliation(s)
- Jun Yan
- Beijing Institute of Basic Medical Sciences; 27 Taiping Road Beijing 100850 P. R. China
| | - Yu Liu
- Beijing Institute of Basic Medical Sciences; 27 Taiping Road Beijing 100850 P. R. China
| | - Yaping Gao
- Beijing Institute of Basic Medical Sciences; 27 Taiping Road Beijing 100850 P. R. China
| | - Jie Dong
- Beijing Institute of Basic Medical Sciences; 27 Taiping Road Beijing 100850 P. R. China
| | - Chunhua Mu
- Beijing Institute of Basic Medical Sciences; 27 Taiping Road Beijing 100850 P. R. China
| | - Di Li
- Beijing Institute of Basic Medical Sciences; 27 Taiping Road Beijing 100850 P. R. China
| | - Guang Yang
- Beijing Institute of Basic Medical Sciences; 27 Taiping Road Beijing 100850 P. R. China
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Gong J, Li D, Yan J, Liu Y, Li D, Dong J, Gao Y, Sun T, Yang G. The accessory gene regulator (agr) controls Staphylococcus aureus virulence in a murine intracranial abscesses model. Braz J Infect Dis 2014; 18:501-6. [PMID: 24833200 PMCID: PMC9428208 DOI: 10.1016/j.bjid.2014.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 02/20/2014] [Accepted: 03/18/2014] [Indexed: 01/14/2023] Open
Abstract
Background Intracranial abscesses are associated with high mortality. Staphylococcus aureus is one of the main pathogens that cause intracranial infection. Until now, there is no report to identify the key effectors of S. aureus during the intracranial infection. Methods The murine intracranial abscesses model induced by S. aureus was constructed. The vital sign and survival rate of mice were observed to evaluate the infection. Histological examination was used to diagnose the pathological alterations of mouse tissues. The sensitivity of S. aureus to whole blood was evaluated by whole-blood killing assay. Results In murine intracranial abscesses model, it was shown that the mortality caused by the accessory gene regulator (agr) locus deficient strain was significant decreased compared with its parent strain. Moreover, we found that RNAIII, the effector of agr system, was essential for the intracranial infection caused by S. aureus. In the further investigation, it was shown that restoration the expression of α-toxin in agr deficient strain could partially recover the mortality in the murine intracranial abscesses model. Conclusion Our data suggested that the agr system of S. aureus is an important virulence determinant in the induction and mortality of intracranial abscesses in mice.
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Affiliation(s)
- Jian Gong
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing Neurosurgical Institute, Beijing, China
| | - Dongzhi Li
- Ningxia Medical University, Incubation Base of National Key Laboratory for Cerebrocranial Diseases, Yinchuan, China
| | - Jun Yan
- Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Yu Liu
- Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Di Li
- Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Jie Dong
- Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Yaping Gao
- Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Tao Sun
- Ningxia Medical University, Incubation Base of National Key Laboratory for Cerebrocranial Diseases, Yinchuan, China.
| | - Guang Yang
- Beijing Institute of Basic Medical Sciences, Beijing, China.
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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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The importance of regulatory RNAs in Staphylococcus aureus. INFECTION GENETICS AND EVOLUTION 2014; 21:616-26. [DOI: 10.1016/j.meegid.2013.11.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 11/12/2013] [Accepted: 11/13/2013] [Indexed: 12/14/2022]
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Abstract
Staphylococcus aureus is a leading pathogen for animals and humans, not only being one of the most frequently isolated bacteria in hospital-associated infections but also causing diseases in the community. To coordinate the expression of its numerous virulence genes for growth and survival, S. aureus uses various signalling pathways that include two-component regulatory systems, transcription factors, and also around 250 regulatory RNAs. Biological roles have only been determined for a handful of these sRNAs, including cis, trans, and cis-trans acting RNAs, some internally encoding small, functional peptides and others possessing dual or multiple functions. Here we put forward an inventory of these fascinating sRNAs; the proteins involved in their activities; and those involved in stress response, metabolisms, and virulence.
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Affiliation(s)
- Julien Guillet
- Rennes University, Inserm U835-UpresEA2311, Pharmaceutical Biochemistry, Rennes, France
| | - Marc Hallier
- Rennes University, Inserm U835-UpresEA2311, Pharmaceutical Biochemistry, Rennes, France
| | - Brice Felden
- Rennes University, Inserm U835-UpresEA2311, Pharmaceutical Biochemistry, Rennes, France
- * E-mail:
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Lioliou E, Sharma CM, Altuvia Y, Caldelari I, Romilly C, Helfer AC, Margalit H, Romby P. In vivo mapping of RNA-RNA interactions in Staphylococcus aureus using the endoribonuclease III. Methods 2013; 63:135-43. [PMID: 23851283 DOI: 10.1016/j.ymeth.2013.06.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 06/26/2013] [Accepted: 06/27/2013] [Indexed: 01/09/2023] Open
Abstract
Ribonucleases play key roles in gene regulation and in the expression of virulence factors in Staphylococcus aureus. Among these enzymes, the double-strand specific endoribonuclease III (RNase III) is a key mediator of mRNA processing and degradation. Recently, we have defined, direct target sites for RNase III processing on a genome-wide scale in S. aureus. Our approach is based on deep sequencing of cDNA libraries obtained from RNAs isolated by in vivo co-immunoprecipitation with wild-type RNase III and two cleavage-defective mutants. The use of such catalytically inactivated enzymes, which still retain their RNA binding capacity, allows the identification of novel RNA substrates of RNase III. In this report, we will summarize the diversity of RNase III functions, discuss the advantages and the limitations of the approach, and how this strategy identifies novel mRNA targets of small non-coding RNAs in S. aureus.
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Affiliation(s)
- Efthimia Lioliou
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 15 rue René Descartes, F-67084 Strasbourg, France
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Chunhua M, Yu L, Yaping G, Jie D, Qiang L, Xiaorong T, Guang Y. The expression of LytM is down-regulated by RNAIII inStaphylococcus aureus. J Basic Microbiol 2012; 52:636-41. [DOI: 10.1002/jobm.201100426] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 11/12/2011] [Indexed: 01/13/2023]
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Romilly C, Caldelari I, Parmentier D, Lioliou E, Romby P, Fechter P. Current knowledge on regulatory RNAs and their machineries in Staphylococcus aureus. RNA Biol 2012; 9:402-13. [PMID: 22546940 DOI: 10.4161/rna.20103] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Staphylococcus aureus is one of the major human pathogens, which causes numerous community-associated and hospital-acquired infections. The regulation of the expression of numerous virulence factors is coordinated by complex interplays between two component systems, transcriptional regulatory proteins, and regulatory RNAs. Recent studies have identified numerous novel RNAs comprising cis-acting regulatory RNAs, antisense RNAs, small non coding RNAs and small mRNAs encoding peptides. We present here several examples of RNAs regulating S. aureus pathogenicity and describe various aspects of antisense regulation.
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Affiliation(s)
- Cédric Romilly
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, Strasbourg, France
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Expression of virulence factors by Staphylococcus aureus grown in serum. Appl Environ Microbiol 2011; 77:8097-105. [PMID: 21926198 DOI: 10.1128/aem.05316-11] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Staphylococcus aureus produces many virulence factors, including toxins, immune-modulatory factors, and exoenzymes. Previous studies involving the analysis of virulence expression were mainly performed by in vitro experiments using bacterial medium. However, when S. aureus infects a host, the bacterial growth conditions are quite different from those in a medium, which may be related to the different expression of virulence factors in the host. In this study, we investigated the expression of virulence factors in S. aureus grown in calf serum. The expression of many virulence factors, including hemolysins, enterotoxins, proteases, and iron acquisition factors, was significantly increased compared with that in bacterial medium. In addition, the expression of RNA III, a global regulon for virulence expression, was significantly increased. This effect was partially restored by the addition of 300 μM FeCl₃ into serum, suggesting that iron depletion is associated with the increased expression of virulence factors in serum. In chemically defined medium without iron, a similar effect was observed. In a mutant with agr inactivated grown in serum, the expression of RNA III, psm, and sec4 was not increased, while other factors were still induced in the mutant, suggesting that another regulatory factor(s) is involved. In addition, we found that serum albumin is a major factor for the capture of free iron to prevent the supply of iron to bacteria grown in serum. These results indicate that S. aureus expresses virulence factors in adaptation to the host environment.
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