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Shen K, Miao W, Zhu L, Hu Q, Ren F, Dong X, Tong H. A 3'UTR-derived small RNA represses pneumolysin synthesis and facilitates pneumococcal brain invasion. Commun Biol 2024; 7:1130. [PMID: 39271946 PMCID: PMC11399405 DOI: 10.1038/s42003-024-06845-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 09/04/2024] [Indexed: 09/15/2024] Open
Abstract
Pneumolysin (Ply) of Streptococcus pneumoniae (pneumococcus) at relatively high and low levels facilitates pneumococcal invasion into the lung and brain, respectively; however, the regulatory mechanisms of Ply expression are poorly understood. Here, we find that a small RNA plyT, processed from the 3'UTR of the ply operon, is expressed higher in anaerobically- than in statically-cultured pneumococcus D39. Using bioinformatic, biochemical and genetic approaches, we reveal that PlyT inhibits Ply synthesis and hemolytic activities by pairing with an RBS-embedded intergenic region of the ply operon. The RNA-binding protein SPD_1558 facilitates the pairing. Importantly, PlyT inhibition of Ply synthesis is stronger in anaerobic culture and leads to lower Ply abundance. Deletion of plyT decreases the number of pneumococci in the infected mouse brain and reduces the virulence, demonstrating that PlyT-regulated lower Ply in oxygen-void microenvironments, such as the blood, is important for pneumococcus to cross the blood-brain barrier and invade the brain. PlyT-mediated repression of Ply synthesis at anoxic niches is also verified in pneumococcal serotype 4 and 14 strains; moreover, the ply operon with a 3'UTR-embedded plyT, and the pairing sequences of IGR and plyT are highly conserved among pneumococcal strains, implying PlyT-regulated Ply synthesis might be widely employed by pneumococcus.
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Affiliation(s)
- Kaiqiang Shen
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Wenshuang Miao
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- School of Basic Medicine, Shenyang Medical College, Shenyang, China
| | - Lin Zhu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qingqing Hu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Fu Ren
- School of Basic Medicine, Shenyang Medical College, Shenyang, China
| | - Xiuzhu Dong
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
- University of Chinese Academy of Sciences, Beijing, China.
| | - Huichun Tong
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
- University of Chinese Academy of Sciences, Beijing, China.
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2
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Yao M, Wang K, Song G, Hu Y, Chen J, Li T, Liang L, Wu J, Xu H, Wang L, Zheng Y, Zhang X, Yin Y, Yao S, Wu K. Transcriptional regulation of TacL-mediated lipoteichoic acids biosynthesis by ComE during competence impacts pneumococcal transformation. Front Cell Infect Microbiol 2024; 14:1375312. [PMID: 38779562 PMCID: PMC11109429 DOI: 10.3389/fcimb.2024.1375312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 04/08/2024] [Indexed: 05/25/2024] Open
Abstract
Competence development is essential for bacterial transformation since it enables bacteria to take up free DNA from the surrounding environment. The regulation of teichoic acid biosynthesis is tightly controlled during pneumococcal competence; however, the mechanism governing this regulation and its impact on transformation remains poorly understood. We demonstrated that a defect in lipoteichoic acid ligase (TacL)-mediated lipoteichoic acids (LTAs) biosynthesis was associated with impaired pneumococcal transformation. Using a fragment of tacL regulatory probe as bait in a DNA pulldown assay, we successfully identified several regulatory proteins, including ComE. Electrophoretic mobility shift assays revealed that phosphomimetic ComE, but not wild-type ComE, exhibited specific binding to the probe. DNase I footprinting assays revealed the specific binding sequences encompassing around 30 base pairs located 31 base pairs upstream from the start codon of tacL. Expression of tacL was found to be upregulated in the ΔcomE strain, and the addition of exogenous competence-stimulating peptide repressed the tacL transcription in the wild-type strain but not the ΔcomE mutant, indicating that ComE exerted a negative regulatory effect on the transcription of tacL. Mutation in the JH2 region of tacL upstream regulatory sequence led to increased LTAs abundance and displayed higher transformation efficiency. Collectively, our work identified the regulatory mechanisms that control LTAs biosynthesis during competence and thereby unveiled a repression mechanism underlying pneumococcal transformation.
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Affiliation(s)
- Miao Yao
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Kun Wang
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Guangming Song
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Yumeng Hu
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Jiali Chen
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Tingting Li
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Longying Liang
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Jie Wu
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Hongmei Xu
- Key Laboratory of Laboratory Medical Diagnostics Designated by the Ministry of Education, School of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Libin Wang
- Key Laboratory of Laboratory Medical Diagnostics Designated by the Ministry of Education, School of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Yuqiang Zheng
- Key Laboratory of Laboratory Medical Diagnostics Designated by the Ministry of Education, School of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Xuemei Zhang
- Key Laboratory of Laboratory Medical Diagnostics Designated by the Ministry of Education, School of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Yibing Yin
- Key Laboratory of Laboratory Medical Diagnostics Designated by the Ministry of Education, School of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Shifei Yao
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
| | - Kaifeng Wu
- Department of Laboratory Medicine, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
- Scientific Research Center, The First People’s Hospital of Zunyi (The Third Affiliated Hospital of Zunyi Medical University), Zunyi, Guizhou, China
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Werren JP, Mostacci N, Gjuroski I, Holivololona L, Troxler LJ, Hathaway LJ, Furrer J, Hilty M. Carbon source-dependent capsule thickness regulation in Streptococcus pneumoniae. Front Cell Infect Microbiol 2023; 13:1279119. [PMID: 38094742 PMCID: PMC10716237 DOI: 10.3389/fcimb.2023.1279119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 10/30/2023] [Indexed: 12/18/2023] Open
Abstract
Background The polysaccharide capsule of Streptococcus pneumoniae plays a major role in virulence, adherence to epithelial cells, and overall survival of the bacterium in the human host. Galactose, mannose, and N-acetylglucosamine (GlcNAc) are likely to be relevant for metabolization in the nasopharynx, while glucose is the primary carbon source in the blood. In this study, we aim to further the understanding of the influence of carbon sources on pneumococcal growth, capsule biosynthesis, and subsequent adherence potential. Methods We tested the growth behavior of clinical wild-type and capsule knockout S. pneumoniae strains, using galactose, GlcNAc, mannose, and glucose as carbon source for growth. We measured capsule thickness and quantified capsule precursors by fluorescein isothiocyanate (FITC)-dextran exclusion assays and 31P-nuclear magnetic resonance measurements, respectively. We also performed epithelial adherence assays using Detroit 562 cells and performed a transcriptome analysis (RNA sequencing). Results We observed a reduced growth in galactose, mannose, and GlcNAc compared to growth in glucose and found capsular size reductions in mannose and GlcNAc compared to galactose and glucose. Additionally, capsular precursor measurements of uridine diphosphate-(UDP)-glucose and UDP-galactose showed less accumulation of precursors in GlcNAc or mannose than in glucose and galactose, indicating a possible link with the received capsular thickness measurements. Epithelial adherence assays showed an increase in adherence potential for a pneumococcal strain, when grown in mannose compared to glucose. Finally, transcriptome analysis of four clinical isolates revealed not only strain specific but also common carbon source-specific gene expression. Conclusion Our findings may indicate a careful adaption of the lifestyle of S. pneumoniae according to the monosaccharides encountered in the respective human niche.
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Affiliation(s)
- Joel P. Werren
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Nadja Mostacci
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Bern, Switzerland
| | - Ilche Gjuroski
- Department of Chemistry, Biochemistry and Pharmacy, University of Bern, Bern, Switzerland
| | - Lalaina Holivololona
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Bern, Switzerland
| | - Lukas J. Troxler
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Bern, Switzerland
| | - Lucy J. Hathaway
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Bern, Switzerland
| | - Julien Furrer
- Department of Chemistry, Biochemistry and Pharmacy, University of Bern, Bern, Switzerland
| | - Markus Hilty
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Bern, Switzerland
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Alibayov B, Scasny A, Vidal AGJ, Murin L, Wong S, Edwards KS, Eichembaun Z, Punshon T, Jackson BP, Hopp MT, McDaniel LS, Akerley BJ, Imhof D, Vidal JE. Oxidation of hemoglobin in the lung parenchyma facilitates the differentiation of pneumococci into encapsulated bacteria. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.14.567109. [PMID: 38014009 PMCID: PMC10680745 DOI: 10.1101/2023.11.14.567109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Pneumococcal pneumonia causes cytotoxicity in the lung parenchyma but the underlying mechanism involves multiple factors contributing to cell death. Here, we discovered that hydrogen peroxide produced by Streptococcus pneumoniae (Spn-H 2 O 2 ) plays a pivotal role by oxidizing hemoglobin, leading to its polymerization and subsequent release of labile heme. At physiologically relevant levels, heme selected a population of encapsulated pneumococci. In the absence of capsule and Spn-H 2 O 2 , host intracellular heme exhibited toxicity towards pneumococci, thus acting as an antibacterial mechanism. Further investigation revealed that heme-mediated toxicity required the ABC transporter GlnPQ. In vivo experiments demonstrated that pneumococci release H 2 O 2 to cause cytotoxicity in bronchi and alveoli through the non-proteolytic degradation of intracellular proteins such as actin, tubulin and GAPDH. Overall, our findings uncover a mechanism of lung toxicity mediated by oxidative stress that favor the growth of encapsulated pneumococci suggesting a therapeutic potential by targeting oxidative reactions. Graphical abstract Highlights Oxidation of hemoglobin by Streptococcus pneumoniae facilitates differentiation to encapsulated pneumococci in vivo Differentiated S. pneumoniae produces capsule and hydrogen peroxide (Spn-H 2 O 2 ) as defense mechanism against host heme-mediated toxicity. Spn-H 2 O 2 -induced lung toxicity causes the oxidation and non-proteolytic degradation of intracellular proteins tubulin, actin, and GAPDH. The ABC transporter GlnPQ is a heme-binding complex that makes Spn susceptible to heme toxicity.
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Chan WT, Garcillán-Barcia MP, Yeo CC, Espinosa M. Type II bacterial toxin-antitoxins: hypotheses, facts, and the newfound plethora of the PezAT system. FEMS Microbiol Rev 2023; 47:fuad052. [PMID: 37715317 PMCID: PMC10532202 DOI: 10.1093/femsre/fuad052] [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: 06/26/2023] [Revised: 08/24/2023] [Accepted: 09/07/2023] [Indexed: 09/17/2023] Open
Abstract
Toxin-antitoxin (TA) systems are entities found in the prokaryotic genomes, with eight reported types. Type II, the best characterized, is comprised of two genes organized as an operon. Whereas toxins impair growth, the cognate antitoxin neutralizes its activity. TAs appeared to be involved in plasmid maintenance, persistence, virulence, and defence against bacteriophages. Most Type II toxins target the bacterial translational machinery. They seem to be antecessors of Higher Eukaryotes and Prokaryotes Nucleotide-binding (HEPN) RNases, minimal nucleotidyltransferase domains, or CRISPR-Cas systems. A total of four TAs encoded by Streptococcus pneumoniae, RelBE, YefMYoeB, Phd-Doc, and HicAB, belong to HEPN-RNases. The fifth is represented by PezAT/Epsilon-Zeta. PezT/Zeta toxins phosphorylate the peptidoglycan precursors, thereby blocking cell wall synthesis. We explore the body of knowledge (facts) and hypotheses procured for Type II TAs and analyse the data accumulated on the PezAT family. Bioinformatics analyses showed that homologues of PezT/Zeta toxin are abundantly distributed among 14 bacterial phyla mostly in Proteobacteria (48%), Firmicutes (27%), and Actinobacteria (18%), showing the widespread distribution of this TA. The pezAT locus was found to be mainly chromosomally encoded whereas its homologue, the tripartite omega-epsilon-zeta locus, was found mostly on plasmids. We found several orphan pezT/zeta toxins, unaccompanied by a cognate antitoxin.
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Affiliation(s)
- Wai Ting Chan
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Maria Pilar Garcillán-Barcia
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-Consejo Superior de Investigaciones Científicas, C/Albert Einstein 22, PCTCAN, 39011 Santander, Spain
| | - Chew Chieng Yeo
- Centre for Research in Infectious Diseases and Biotechnology (CeRIDB), Faculty of Medicine
, Universiti Sultan Zainal Abidin, Jalan Sultan Mahumd, 20400 Kuala Terengganu, Malaysia
| | - Manuel Espinosa
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, 9, 28040 Madrid, Spain
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Chavanet P, Fournel I, Bourredjem A, Piroth L, Blot M, Sixt T, Binquet C. Addition of daptomycin for the treatment of pneumococcal meningitis: protocol for the AddaMAP study. BMJ Open 2023; 13:e073032. [PMID: 37491088 PMCID: PMC10373719 DOI: 10.1136/bmjopen-2023-073032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/27/2023] Open
Abstract
BACKGROUND The leading cause of acute bacterial meningitis in adults is Streptococcus pneumoniae. This infection is associated with high rates of mortality and morbidity related, among other factors, to the excessive host response to the pneumococcal lysis. Experimental in vitro and in vivo data show that the combination of corticosteroids/third-generation cephalosporins and the non-lytic antibiotic, daptomycin, has synergistic effects with (1) a rapid cerebrospinal fluid sterilisation, (2) less brain damages and (3) less loss of cognitive performances. Despite these encouraging results, daptomycin has never been evaluated in adult patients with pneumococcal meningitis. METHODS AND ANALYSIS The AddaMAP trial is a phase II, open-label, Simon's two-stage, multicentre trial that has been designed to assess the efficacy and safety of adding daptomycin (10 mg/kg/d for 8 days) to the recommended treatment (corticosteroids+third generation cephalosporin) in adults with confirmed pneumococcal meningitis. The main endpoint is the disability-free survival (defined as modified Rankin Scale mRS≤2) at day 30. Secondary outcomes are overall mortality, disability at D30 and D90 (mRS, Glasgow Coma Scale and Glasgow Outcome Scales, mini-mental score), hearing loss (Hearing Handicap Inventory Test at D30 and D90, routine audiometric test and Hearing-it test at D30), and quality of life (12-item Short Form Survey and WHO QOL BREF). Seventy-two analysable patients are required. ETHICS AND DISSEMINATION The study protocol was approved by the Institutional Review Board of the IDF 1 of the ethics committee on 16 January 2018, and authorisation was obtained from the Agence Nationale de Securité des Médicaments et des Produits de Santé on 22 September 2017. The results will be submitted for publication in a peer-reviewed journal. TRIAL REGISTRATION NUMBER NCT03480191.
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Affiliation(s)
- Pascal Chavanet
- Infectious Diseases Department, University Hospital, Dijon, France
- INSERM, CIC 1432, Module Epidémiologie Clinique, Dijon, France
| | - Isabelle Fournel
- INSERM, CIC 1432, Module Epidémiologie Clinique, Dijon, France
- Centre d'Investigation Clinique, CHU Dijon, Dijon, France
| | - Abderrahmane Bourredjem
- INSERM, CIC 1432, Module Epidémiologie Clinique, Dijon, France
- Centre d'Investigation Clinique, CHU Dijon, Dijon, France
| | - Lionel Piroth
- Infectious Diseases Department, University Hospital, Dijon, France
| | - Mathieu Blot
- Infectious Diseases Department, University Hospital, Dijon, France
| | - Thibault Sixt
- Infectious Diseases Department, University Hospital, Dijon, France
| | - Christine Binquet
- INSERM, CIC 1432, Module Epidémiologie Clinique, Dijon, France
- Centre d'Investigation Clinique, CHU Dijon, Dijon, France
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Hu D, Laczkovich I, Federle MJ, Morrison DA. Identification and Characterization of Negative Regulators of Rgg1518 Quorum Sensing in Streptococcus pneumoniae. J Bacteriol 2023; 205:e0008723. [PMID: 37341600 PMCID: PMC10367586 DOI: 10.1128/jb.00087-23] [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: 03/21/2023] [Accepted: 06/02/2023] [Indexed: 06/22/2023] Open
Abstract
Streptococcus pneumoniae is an agent of otitis media, septicemia, and meningitis and remains the leading cause of community-acquired pneumonia regardless of vaccine use. Of the various strategies that S. pneumoniae takes to enhance its potential to colonize the human host, quorum sensing (QS) is an intercellular communication process that provides coordination of gene expression at a community level. Numerous putative QS systems are identifiable in the S. pneumoniae genome, but their gene-regulatory activities and contributions to fitness have yet to be fully evaluated. To contribute to assessing regulatory activities of rgg paralogs present in the D39 genome, we conducted transcriptomic analysis of mutants of six QS regulators. Our results find evidence that at least four QS regulators impact the expression of a polycistronic operon (encompassing genes spd_1517 to spd_1513) that is directly controlled by the Rgg/SHP1518 QS system. As an approach to unravel the convergent regulation placed on the spd_1513-1517 operon, we deployed transposon mutagenesis screening in search of upstream regulators of the Rgg/SHP1518 QS system. The screen identified two types of insertion mutants that result in increased activity of Rgg1518-dependent transcription, one type being where the transposon inserted into pepO, an annotated endopeptidase, and the other type being insertions in spxB, a pyruvate oxidase. We demonstrate that pneumococcal PepO degrades SHP1518 to prevent activation of Rgg/SHP1518 QS. Moreover, the glutamic acid residue in the conserved "HExxH" domain is indispensable for the catalytic function of PepO. Finally, we confirmed the metalloendopeptidase property of PepO, which requires zinc ions, but not other ions, to facilitate peptidyl hydrolysis. IMPORTANCE Streptococcus pneumoniae uses quorum sensing to communicate and regulate virulence. In our study, we focused on one Rgg quorum sensing system (Rgg/SHP1518) and found that multiple other Rgg regulators also control it. We further identified two enzymes that inhibit Rgg/SHP1518 signaling and revealed and validated one enzyme's mechanisms for breaking down quorum sensing signaling molecules. Our findings shed light on the complex regulatory network of quorum sensing in Streptococcus pneumoniae.
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Affiliation(s)
- Duoyi Hu
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Irina Laczkovich
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Michael J. Federle
- Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
- Center for Biomolecular Science, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Donald A. Morrison
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
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Zhang Y, Zhang J, Xiao J, Wang H, Yang R, Guo X, Zheng Y, Yin Y, Zhang X. comCDE (Competence) Operon Is Regulated by CcpA in Streptococcus pneumoniae D39. Microbiol Spectr 2023; 11:e0001223. [PMID: 37036382 PMCID: PMC10269683 DOI: 10.1128/spectrum.00012-23] [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: 01/06/2023] [Accepted: 02/16/2023] [Indexed: 04/11/2023] Open
Abstract
Natural transformation plays an important role in the formation of drug-resistant bacteria. Exploring the regulatory mechanism of natural transformation can aid the discovery of new antibacterial targets and reduce the emergence of drug-resistant bacteria. Competence is a prerequisite of natural transformation in Streptococcus pneumoniae, in which comCDE operon is the core regulator of competence. To date, only ComE has been shown to directly regulate comCDE transcription. In this study, a transcriptional regulator, the catabolite control protein A (CcpA), was identified that directly regulated comCDE transcription. We confirmed that CcpA binds to the cis-acting catabolite response elements (cre) in the comCDE promoter region to regulate comCDE transcription and transformation. Moreover, CcpA can coregulate comCDE transcription with phosphorylated and dephosphorylated ComE. Regulation of comCDE transcription and transformation by CcpA was also affected by carbon source signals. Together, these insights demonstrate the versatility of CcpA and provide a theoretical basis for reducing the emergence of drug-resistant bacteria. IMPORTANCE Streptococcus pneumoniae is a major cause of bacterial infections in humans, such as pneumonia, bacteremia, meningitis, otitis media, and sinusitis. Like most streptococci, S. pneumoniae is naturally competent and employs this ability to augment its adaptive evolution. The current study illustrates CcpA, a carbon catabolite regulator, can participate in the competence process by regulating comCDE transcription, and this process is regulated by different carbon source signals. These hidden abilities are likely critical for adaptation and colonization in the environment.
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Affiliation(s)
- Yapeng Zhang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | | | - Jiangming Xiao
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Hanyi Wang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Rui Yang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Xinlin Guo
- Department of Medicine Laboratory, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Yuqiang Zheng
- Department of Medicine Laboratory, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Yibing Yin
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Xuemei Zhang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, China
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9
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Frantz SI, Small CM, Cresko WA, Singh ND. Ovarian transcriptional response to Wolbachia infection in D. melanogaster in the context of between-genotype variation in gene expression. G3 (BETHESDA, MD.) 2023; 13:jkad047. [PMID: 36857313 PMCID: PMC10151400 DOI: 10.1093/g3journal/jkad047] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 08/22/2022] [Accepted: 01/07/2023] [Indexed: 03/02/2023]
Abstract
Wolbachia is a maternally transmitted endosymbiotic bacteria that infects a wide variety of arthropod and nematode hosts. The effects of Wolbachia on host biology are far-reaching and include changes in host gene expression. However, previous work on the host transcriptional response has generally been investigated in the context of a single host genotype. Thus, the relative effect of Wolbachia infection versus vs. host genotype on gene expression is unknown. Here, we explicitly test the relative roles of Wolbachia infection and host genotype on host gene expression by comparing the ovarian transcriptomes of 4 strains of Drosophila melanogaster (D. melanogaster) infected and uninfected with Wolbachia. Our data suggest that infection explains a small amount of transcriptional variation, particularly in comparison to variation in gene expression among strains. However, infection specifically affects genes related to cell cycle, translation, and metabolism. We also find enrichment of cell division and recombination processes among genes with infection-associated differential expression. Broadly, the transcriptomic changes identified in this study provide novel understanding of the relative magnitude of the effect of Wolbachia infection on gene expression in the context of host genetic variation and also point to genes that are consistently differentially expressed in response to infection among multiple genotypes.
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Affiliation(s)
- Sophia I Frantz
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, 97403USA
| | - Clayton M Small
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, 97403USA
- Presidential Initiative in Data Science, University of Oregon, Eugene, OR, 97403USA
| | - William A Cresko
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, 97403USA
- Presidential Initiative in Data Science, University of Oregon, Eugene, OR, 97403USA
| | - Nadia D Singh
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, 97403USA
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10
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Pettersen JS, Høg FF, Nielsen FD, Møller-Jensen J, Jørgensen MG. Global transcriptional responses of pneumococcus to human blood components and cerebrospinal fluid. Front Microbiol 2022; 13:1060583. [PMID: 36620004 PMCID: PMC9812572 DOI: 10.3389/fmicb.2022.1060583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 11/22/2022] [Indexed: 12/24/2022] Open
Abstract
Streptococcus pneumoniae (pneumococcus) is a leading cause of severe invasive infectious diseases such as sepsis and meningitis. Understanding how pneumococcus adapts and survive in the human bloodstream environment and cerebrospinal fluid (CSF) is important for development of future treatment strategies. This study investigates the global transcriptional response of pneumococcus to human blood components and CSF acquired from discarded and anonymized patient samples. Extensive transcriptional changes to human blood components were observed during early stages of interaction. Plasma-specific responses were primarily related to metabolic components and include strong downregulation of fatty acid biosynthesis genes, and upregulation of nucleotide biosynthesis genes. No transcriptional responses specific to the active plasma proteins (e.g., complement proteins) were observed during early stages of interaction as demonstrated by a differential expression analysis between plasma and heat-inactivated plasma. The red blood cell (RBC)-specific response was far more complex, and included activation of the competence system, differential expression of several two-component systems, phosphotransferase systems and transition metal transporter genes. Interestingly, most of the changes observed for CSF were also observed for plasma. One of the few CSF-specific responses, not observed for plasma, was a strong downregulation of the iron acquisition system piuBCDA. Intriguingly, this transcriptomic analysis also uncovers significant differential expression of more than 20 small non-coding RNAs, most of them in response to RBCs, including small RNAs from uncharacterized type I toxin-antitoxin systems. In summary, this transcriptomic study identifies key pneumococcal metabolic pathways and regulatory genes involved with adaptation to human blood and CSF. Future studies should uncover the potential involvement of these factors with virulence in-vivo.
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11
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Alibayov B, Scasny A, Khan F, Creel A, Smith P, Vidal AGJ, Fitisemanu FM, Padilla-Benavides T, Weiser JN, Vidal JE. Oxidative Reactions Catalyzed by Hydrogen Peroxide Produced by Streptococcus pneumoniae and Other Streptococci Cause the Release and Degradation of Heme from Hemoglobin. Infect Immun 2022; 90:e0047122. [PMID: 36409115 PMCID: PMC9753736 DOI: 10.1128/iai.00471-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 10/25/2022] [Indexed: 11/23/2022] Open
Abstract
Streptococcus pneumoniae (Spn) strains cause pneumonia that kills millions every year worldwide. Spn produces Ply, a hemolysin that lyses erythrocytes releasing hemoglobin, and also produces the pro-oxidant hydrogen peroxide (Spn-H2O2) during growth. The hallmark of the pathophysiology of hemolytic diseases is the oxidation of hemoglobin, but oxidative reactions catalyzed by Spn-H2O2 have been poorly studied. We characterized the oxidation of hemoglobin by Spn-H2O2. We prepared a series of single-mutant (ΔspxB or ΔlctO), double-mutant (ΔspxB ΔlctO), and complemented strains in TIGR4, D39, and EF3030. We then utilized an in vitro model with oxyhemoglobin to demonstrate that oxyhemoglobin was oxidized rapidly, within 30 min of incubation, by Spn-H2O2 to methemoglobin and that the main source of Spn-H2O2 was pyruvate oxidase (SpxB). Moreover, extended incubation caused the release and the degradation of heme. We then assessed oxidation of hemoglobin and heme degradation by other bacterial inhabitants of the respiratory tract. All hydrogen peroxide-producing streptococci tested caused the oxidation of hemoglobin and heme degradation, whereas bacterial species that produce <1 μM H2O2 neither oxidized hemoglobin nor degraded heme. An ex vivo bacteremia model confirmed that oxidation of hemoglobin and heme degradation occurred concurrently with hemoglobin that was released from erythrocytes by Ply. Finally, gene expression studies demonstrated that heme, but not red blood cells or hemoglobin, induced upregulated transcription of the spxB gene. Oxidation of hemoglobin may be important for pathogenesis and for the symbiosis of hydrogen peroxide-producing bacteria with other species by providing nutrients such as iron.
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Affiliation(s)
- Babek Alibayov
- Department of Cell and Molecular Biology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Anna Scasny
- Department of Cell and Molecular Biology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Faidad Khan
- Department of Cell and Molecular Biology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Aidan Creel
- Department of Cell and Molecular Biology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
- Summer Undergraduate Research Experience Program, School of Graduate Studies in the Health Sciences, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Perriann Smith
- Department of Cell and Molecular Biology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
- Mississippi INBRE program, University of Southern Mississippi, Hattiesburg, Mississippi, USA
| | - Ana G. Jop Vidal
- Department of Cell and Molecular Biology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | | | | | - Jeffrey N. Weiser
- Department of Microbiology, NYU Langone Health, New York, New York, USA
| | - Jorge E. Vidal
- Department of Cell and Molecular Biology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
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12
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Discovery and structure of a widespread bacterial ABC transporter specific for ergothioneine. Nat Commun 2022; 13:7586. [PMID: 36481738 PMCID: PMC9732360 DOI: 10.1038/s41467-022-35277-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 11/22/2022] [Indexed: 12/13/2022] Open
Abstract
L-Ergothioneine (ET), the 2-thioimidazole derivative of trimethylhistidine, is biosynthesized by select fungi and bacteria, notably Mycobacterium tuberculosis, and functions as a scavenger of reactive oxygen species. The extent to which ET broadly functions in bacterial cells unable to synthesize it is unknown. Here we show that spd_1642-1643 in Streptococcus pneumoniae, a Gram-positive respiratory pathogen, encodes an ET uptake ATP-binding cassette (ABC) transporter, designated EgtU. The solute binding domain (SBD) of EgtU, EgtUC, binds ET with high affinity and exquisite specificity in a cleft between the two subdomains, with cation-π interactions engaging the betaine moiety and a network of water molecules that surround the thioimidazole ring. EgtU is highly conserved among known quaternary amine compound-specific transporters and widely distributed in Firmicutes, including the human pathogens Listeria monocytogenes, as BilEB, Enterococcus faecalis and Staphylococcus aureus. ET increases the chemical diversity of the low molecular weight thiol pool in Gram-positive human pathogens and may contribute to antioxidant defenses in the infected host.
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13
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Ruhluel D, O'Brien S, Fothergill JL, Neill DR. Development of liquid culture media mimicking the conditions of sinuses and lungs in cystic fibrosis and health. F1000Res 2022; 11:1007. [PMID: 36519007 PMCID: PMC9718992 DOI: 10.12688/f1000research.125074.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/26/2022] [Indexed: 11/25/2023] Open
Abstract
The respiratory tract is a compartmentalised and heterogenous environment. The nasopharynx and sinuses of the upper airways have distinct properties from the lungs and these differences may shape bacterial adaptation and evolution. Upper airway niches act as early colonisation sites for respiratory bacterial pathogens, including those, such as Pseudomonas aeruginosa, that can go on to establish chronic infection of the lungs in people with cystic fibrosis (CF). Despite the importance of upper airway environments in facilitating early adaptation to host environments, currently available in vitro models for study of respiratory infection in CF focus exclusively on the lungs. Furthermore, animal models, widely used to bridge the gap between in vitro systems and the clinical scenario, do not allow the upper and lower airways to be studied in isolation. We have developed a suite of culture media reproducing key features of the upper and lower airways, for the study of bacterial adaptation and evolution in different respiratory environments. For both upper and lower airway-mimicking media, we have developed formulations that reflect airway conditions in health and those that reflect the altered environment of the CF respiratory tract. Here, we describe the development and validation of these media and their use for study of genetic and phenotypic adaptations in P. aeruginosa during growth under upper or lower airway conditions in health and in CF.
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Affiliation(s)
- Dilem Ruhluel
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
| | - Siobhan O'Brien
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, 2, Ireland
| | - Joanne L Fothergill
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
| | - Daniel R Neill
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
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14
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Ruhluel D, O'Brien S, Fothergill JL, Neill DR. Development of liquid culture media mimicking the conditions of sinuses and lungs in cystic fibrosis and health. F1000Res 2022; 11:1007. [PMID: 36519007 PMCID: PMC9718992 DOI: 10.12688/f1000research.125074.2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/18/2022] [Indexed: 12/05/2022] Open
Abstract
The respiratory tract is a compartmentalised and heterogenous environment. The nasopharynx and sinuses of the upper airways have distinct properties from the lungs and these differences may shape bacterial adaptation and evolution. Upper airway niches act as early colonisation sites for respiratory bacterial pathogens, including those, such as Pseudomonas aeruginosa, that can go on to establish chronic infection of the lungs in people with cystic fibrosis (CF). Despite the importance of upper airway environments in facilitating early adaptation to host environments, currently available in vitro models for study of respiratory infection in CF focus exclusively on the lungs. Furthermore, animal models, widely used to bridge the gap between in vitro systems and the clinical scenario, do not allow the upper and lower airways to be studied in isolation. We have developed a suite of culture media reproducing key features of the upper and lower airways, for the study of bacterial adaptation and evolution in different respiratory environments. For both upper and lower airway-mimicking media, we have developed formulations that reflect airway conditions in health and those that reflect the altered environment of the CF respiratory tract. Here, we describe the development and validation of these media and their use for study of genetic and phenotypic adaptations in P. aeruginosa during growth under upper or lower airway conditions in health and in CF.
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Affiliation(s)
- Dilem Ruhluel
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
| | - Siobhan O'Brien
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, 2, Ireland
| | - Joanne L Fothergill
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
| | - Daniel R Neill
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
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15
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Basset A, Wall E, Mitsi E, Deshusses C, Daly R, Pojar S, Reiné J, Guerra-Assuncao JA, Denis B, Jochems SP, Heyderman R, Brown J, Lu YJ, Ferreira DM, Malley R. Targeted Transcriptomic Screen of Pneumococcal Genes Expressed during Murine and Human Infection. Infect Immun 2022; 90:e0017522. [PMID: 35674445 PMCID: PMC9302103 DOI: 10.1128/iai.00175-22] [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: 04/28/2022] [Accepted: 05/04/2022] [Indexed: 11/20/2022] Open
Abstract
The advent of pneumococcal conjugate vaccines led to the near disappearance of most of the included serotypes in high-income settings but also the rise of nonvaccine-type colonization and disease. Alternative strategies, using genetically conserved proteins as antigens, have been evaluated preclinically and clinically for years, so far unsuccessfully. One possible explanation for the failure of these efforts is that the choice of antigens may not have been sufficiently guided by an understanding of the gene expression pattern in the context of infection. Here, we present a targeted transcriptomic analysis of 160 pneumococcal genes encoding bacterial surface-exposed proteins in mouse models, human colonization, and human meningitis. We present the overlap of these different transcriptomic profiles. We identify two bacterial genes that are highly expressed in the context of mouse and human infection: SP_0282, an IID component of a mannose phosphotransferase system (PTS), and SP_1739, encoding RNase Y. We show that these two proteins can confer protection against pneumococcal nasopharyngeal colonization and intraperitoneal challenge in a murine model and generate opsonophagocytic antibodies. This study emphasizes and confirms the importance of studies of pneumococcal gene expression of bacterial surface proteins during human infection and colonization and may pave the way for the selection of a protein-based vaccine candidate.
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Affiliation(s)
- Alan Basset
- Division of Infectious Diseases, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Emma Wall
- Research Division of Infection, University College London, London, United Kingdom
- Francis Crick Institute, London, United Kingdom
| | - Elena Mitsi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Chloe Deshusses
- Division of Infectious Diseases, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Raecliffe Daly
- Division of Infectious Diseases, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Sherin Pojar
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Jesús Reiné
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | | | | - Simon P. Jochems
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Robert Heyderman
- Research Division of Infection, University College London, London, United Kingdom
| | - Jeremy Brown
- Research Division of Infection, University College London, London, United Kingdom
| | - Ying-Jie Lu
- Division of Infectious Diseases, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Daniela M. Ferreira
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Richard Malley
- Division of Infectious Diseases, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
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16
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Discovery of Unannotated Small Open Reading Frames in Streptococcus pneumoniae D39 Involved in Quorum Sensing and Virulence Using Ribosome Profiling. mBio 2022; 13:e0124722. [PMID: 35852327 PMCID: PMC9426450 DOI: 10.1128/mbio.01247-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus pneumoniae, an opportunistic human pathogen, is the leading cause of community-acquired pneumonia and an agent of otitis media, septicemia, and meningitis. Although genomic and transcriptomic studies of S. pneumoniae have provided detailed perspectives on gene content and expression programs, they have lacked information pertaining to the translational landscape, particularly at a resolution that identifies commonly overlooked small open reading frames (sORFs), whose importance is increasingly realized in metabolism, regulation, and virulence. To identify protein-coding sORFs in S. pneumoniae, antibiotic-enhanced ribosome profiling was conducted. Using translation inhibitors, 114 novel sORFs were detected, and the expression of a subset of them was experimentally validated. Two loci associated with virulence and quorum sensing were examined in deeper detail. One such sORF, rio3, overlaps with the noncoding RNA srf-02 that was previously implicated in pathogenesis. Targeted mutagenesis parsing rio3 from srf-02 revealed that rio3 is responsible for the fitness defect seen in a murine nasopharyngeal colonization model. Additionally, two novel sORFs located adjacent to the quorum sensing receptor rgg1518 were found to impact regulatory activity. Our findings emphasize the importance of sORFs present in the genomes of pathogenic bacteria and underscore the utility of ribosome profiling for identifying the bacterial translatome.
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17
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Moreno-Blanco A, Solano-Collado V, Ortuno-Camuñas A, Espinosa M, Ruiz-Cruz S, Bravo A. PclR is a transcriptional activator of the gene that encodes the pneumococcal collagen-like protein PclA. Sci Rep 2022; 12:11827. [PMID: 35821046 PMCID: PMC9276737 DOI: 10.1038/s41598-022-15758-7] [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: 03/04/2022] [Accepted: 06/29/2022] [Indexed: 11/09/2022] Open
Abstract
The Gram-positive bacterium Streptococcus pneumoniae is a major human pathogen that shows high levels of genetic variability. The pneumococcal R6 genome harbours several gene clusters that are not present in all strains of the species. One of these clusters contains two divergent genes, pclA, which encodes a putative surface-exposed protein that contains large regions of collagen-like repeats, and spr1404 (here named pclR). PclA was shown to mediate pneumococcal adherence to host cells in vitro. In this work, we demonstrate that PclR (494 amino acids) is a transcriptional activator. It stimulates transcription of the pclA gene by binding to a specific DNA site upstream of the core promoter. In addition, we show that PclR has common features with the MgaSpn transcriptional regulator (493 amino acids), which is also encoded by the R6 genome. These proteins have high sequence similarity (60.3%), share the same organization of predicted functional domains, and generate multimeric complexes on linear double-stranded DNAs. However, on the PpclA promoter region, MgaSpn binds to a site different from the one recognized by PclR. Our results indicate that PclR and MgaSpn have similar DNA-binding properties but different DNA-binding specificities, pointing to a different regulatory role of both proteins.
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Affiliation(s)
- Ana Moreno-Blanco
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Virtu Solano-Collado
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain.,Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Alejandro Ortuno-Camuñas
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Manuel Espinosa
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Sofía Ruiz-Cruz
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain. .,School of Microbiology, University College Cork and APC Microbiome Ireland, Western Road, Cork, T12 YT20, Ireland.
| | - Alicia Bravo
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain.
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18
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Dewachter L, Dénéréaz J, Liu X, de Bakker V, Costa C, Baldry M, Sirard JC, Veening JW. Amoxicillin-resistant Streptococcus pneumoniae can be resensitized by targeting the mevalonate pathway as indicated by sCRilecs-seq. eLife 2022; 11:e75607. [PMID: 35748540 PMCID: PMC9363119 DOI: 10.7554/elife.75607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 06/23/2022] [Indexed: 11/23/2022] Open
Abstract
Antibiotic resistance in the important opportunistic human pathogen Streptococcus pneumoniae is on the rise. This is particularly problematic in the case of the β-lactam antibiotic amoxicillin, which is the first-line therapy. It is therefore crucial to uncover targets that would kill or resensitize amoxicillin-resistant pneumococci. To do so, we developed a genome-wide, single-cell based, gene silencing screen using CRISPR interference called sCRilecs-seq (subsets of CRISPR interference libraries extracted by fluorescence activated cell sorting coupled to next generation sequencing). Since amoxicillin affects growth and division, sCRilecs-seq was used to identify targets that are responsible for maintaining proper cell size. Our screen revealed that downregulation of the mevalonate pathway leads to extensive cell elongation. Further investigation into this phenotype indicates that it is caused by a reduced availability of cell wall precursors at the site of cell wall synthesis due to a limitation in the production of undecaprenyl phosphate (Und-P), the lipid carrier that is responsible for transporting these precursors across the cell membrane. The data suggest that, whereas peptidoglycan synthesis continues even with reduced Und-P levels, cell constriction is specifically halted. We successfully exploited this knowledge to create a combination treatment strategy where the FDA-approved drug clomiphene, an inhibitor of Und-P synthesis, is paired up with amoxicillin. Our results show that clomiphene potentiates the antimicrobial activity of amoxicillin and that combination therapy resensitizes amoxicillin-resistant S. pneumoniae. These findings could provide a starting point to develop a solution for the increasing amount of hard-to-treat amoxicillin-resistant pneumococcal infections.
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Affiliation(s)
- Liselot Dewachter
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore BuildingLausanneSwitzerland
| | - Julien Dénéréaz
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore BuildingLausanneSwitzerland
| | - Xue Liu
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore BuildingLausanneSwitzerland
- Guangdong Key Laboratory for Genome Stability and Human Disease Prevention, Department of Pharmacology, International Cancer Center, Shenzhen University Health Science CenterShenzhenChina
| | - Vincent de Bakker
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore BuildingLausanneSwitzerland
| | - Charlotte Costa
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of LilleLilleFrance
| | - Mara Baldry
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of LilleLilleFrance
| | - Jean-Claude Sirard
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of LilleLilleFrance
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore BuildingLausanneSwitzerland
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19
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Diagne AM, Pelletier A, Durmort C, Faure A, Kanonenberg K, Freton C, Page A, Delolme F, Vorac J, Vallet S, Bellard L, Vivès C, Fieschi F, Vernet T, Rousselle P, Guiral S, Grangeasse C, Jault JM, Orelle C. Identification of a two-component regulatory system involved in antimicrobial peptide resistance in Streptococcus pneumoniae. PLoS Pathog 2022; 18:e1010458. [PMID: 35395062 PMCID: PMC9020739 DOI: 10.1371/journal.ppat.1010458] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 04/20/2022] [Accepted: 03/18/2022] [Indexed: 11/24/2022] Open
Abstract
Two-component regulatory systems (TCS) are among the most widespread mechanisms that bacteria use to sense and respond to environmental changes. In the human pathogen Streptococcus pneumoniae, a total of 13 TCS have been identified and many of them have been linked to pathogenicity. Notably, TCS01 strongly contributes to pneumococcal virulence in several infection models. However, it remains one of the least studied TCS in pneumococci and its functional role is still unclear. In this study, we demonstrate that TCS01 cooperates with a BceAB-type ABC transporter to sense and induce resistance to structurally-unrelated antimicrobial peptides of bacterial origin that all target undecaprenyl-pyrophosphate or lipid II, which are essential precursors of cell wall biosynthesis. Even though tcs01 and bceAB genes do not locate in the same gene cluster, disruption of either of them equally sensitized the bacterium to the same set of antimicrobial peptides. We show that the key function of TCS01 is to upregulate the expression of the transporter, while the latter appears the main actor in resistance. Electrophoretic mobility shift assays further demonstrated that the response regulator of TCS01 binds to the promoter region of the bceAB genes, implying a direct control of these genes. The BceAB transporter was overexpressed and purified from E. coli. After reconstitution in liposomes, it displayed substantial ATPase and GTPase activities that were stimulated by antimicrobial peptides to which it confers resistance to, revealing new functional features of a BceAB-type transporter. Altogether, this inducible defense mechanism likely contributes to the survival of the opportunistic microorganism in the human host, in which competition among commensal microorganisms is a key determinant for effective host colonization and invasive path.
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Affiliation(s)
- Aissatou Maty Diagne
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Anaïs Pelletier
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Claire Durmort
- Institute of Structural Biology (IBS), UMR 5075 CNRS/University of Grenoble-Alpes, Grenoble, France
| | - Agathe Faure
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Kerstin Kanonenberg
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Céline Freton
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Adeline Page
- Protein Science Facility, SFR BioSciences, CNRS, UMS3444, INSERM US8, University of Lyon, Lyon, France
| | - Frédéric Delolme
- Protein Science Facility, SFR BioSciences, CNRS, UMS3444, INSERM US8, University of Lyon, Lyon, France
| | - Jaroslav Vorac
- Institute of Structural Biology (IBS), UMR 5075 CNRS/University of Grenoble-Alpes, Grenoble, France
| | - Sylvain Vallet
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Laure Bellard
- Institute of Structural Biology (IBS), UMR 5075 CNRS/University of Grenoble-Alpes, Grenoble, France
| | - Corinne Vivès
- Institute of Structural Biology (IBS), UMR 5075 CNRS/University of Grenoble-Alpes, Grenoble, France
| | - Franck Fieschi
- Institute of Structural Biology (IBS), UMR 5075 CNRS/University of Grenoble-Alpes, Grenoble, France
| | - Thierry Vernet
- Institute of Structural Biology (IBS), UMR 5075 CNRS/University of Grenoble-Alpes, Grenoble, France
| | - Patricia Rousselle
- Laboratoire de Biologie Tissulaire et Ingénierie Thérapeutique (LBTI), UMR 5305 CNRS/University of Lyon, Lyon, France
| | - Sébastien Guiral
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Christophe Grangeasse
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Jean-Michel Jault
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Cédric Orelle
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
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20
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Janoušková M, Straw ML, Su YC, Riesbeck K. Gene Expression Regulation in Airway Pathogens: Importance for Otitis Media. Front Cell Infect Microbiol 2022; 12:826018. [PMID: 35252035 PMCID: PMC8895709 DOI: 10.3389/fcimb.2022.826018] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/19/2022] [Indexed: 11/13/2022] Open
Abstract
Otitis media (OM) is an inflammatory disorder in the middle ear. It is mainly caused by viruses or bacteria associated with the airways. Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis are the three main pathogens in infection-related OM, especially in younger children. In this review, we will focus upon the multifaceted gene regulation mechanisms that are well-orchestrated in S. pneumoniae, H. influenzae, and M. catarrhalis during the course of infection in the middle ear either in experimental OM or in clinical settings. The sophisticated findings from the past 10 years on how the othopathogens govern their virulence phenotypes for survival and host adaptation via phase variation- and quorum sensing-dependent gene regulation, will be systematically discussed. Comprehensive understanding of gene expression regulation mechanisms employed by pathogens during the onset of OM may provide new insights for the design of a new generation of antimicrobial agents in the fight against bacterial pathogens while combating the serious emergence of antimicrobial resistance.
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21
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Xiao S, Suo W, Zhang J, Zhang X, Yin Y, Guo X, Zheng Y. Mga Spn is a negative regulator of capsule and phosphorylcholine biosynthesis and influences the virulence of Streptococcus pneumoniae D39. Virulence 2021; 12:2366-2381. [PMID: 34506260 PMCID: PMC8437459 DOI: 10.1080/21505594.2021.1972539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Global transcriptional regulators are prevalent in gram-positive pathogens. The transcriptional regulators of the Mga/AtxA family regulate target gene expression by directly binding to the promoter regions, that results in the coordinated expression of virulence factors. The spd_1587 gene of Streptococcus pneumoniae strain D39 encodes MgaSpn, which shares sequence similarity with global transcriptional regulators of the Mga/AtxA family. In this study, we demonstrated that MgaSpn regulates the biosynthesis of the capsule and phosphorylcholine, which play key roles in disease severity in S. pneumoniae infections. MgaSpn directly binds to the cps and lic1 promoters and affects the biosynthesis of the capsule and phosphorylcholine. MgaSpn binds to two specific sites on the promoter of cps, one of which contains the −35 box of the promoter, with high affinity. Consistently, low-molecular-weight capsule components were observed in the mgaSpn-null mutant strain. Moreover, we found that phosphorylcholine content was notably increased in the unencapsulated mgaSpn mutant strain. The mgaSpn null mutant caused more severe systemic disease than the parental strain D39. These findings indicate that the pneumococcal MgaSpn protein can inhibit capsule and phosphorylcholine production, thereby affecting the virulence of S. pneumoniae.
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Affiliation(s)
- Shengnan Xiao
- Department of Medicine Laboratory, Children's Hospital of Chongqing Medical University; National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders; and Chongqing Key Laboratory of Pediatrics, Chongqing, People's Republic of China
| | - Weicai Suo
- Department of Medicine Laboratory, Children's Hospital of Chongqing Medical University; National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders; and Chongqing Key Laboratory of Pediatrics, Chongqing, People's Republic of China
| | - Jinghui Zhang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, People's Republic of China
| | - Xuemei Zhang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, People's Republic of China
| | - Yibing Yin
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, People's Republic of China
| | - Xinlin Guo
- Department of Medicine Laboratory, Children's Hospital of Chongqing Medical University; National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders; and Chongqing Key Laboratory of Pediatrics, Chongqing, People's Republic of China
| | - Yuqiang Zheng
- Department of Medicine Laboratory, Children's Hospital of Chongqing Medical University; National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders; and Chongqing Key Laboratory of Pediatrics, Chongqing, People's Republic of China
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22
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Green AE, Howarth D, Chaguza C, Echlin H, Langendonk RF, Munro C, Barton TE, Hinton JCD, Bentley SD, Rosch JW, Neill DR. Pneumococcal Colonization and Virulence Factors Identified Via Experimental Evolution in Infection Models. Mol Biol Evol 2021; 38:2209-2226. [PMID: 33502519 PMCID: PMC8136498 DOI: 10.1093/molbev/msab018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Streptococcus pneumoniae is a commensal of the human nasopharynx and a major cause of respiratory and invasive disease. We examined adaptation and evolution of pneumococcus, within nasopharynx and lungs, in an experimental system where the selective pressures associated with transmission were removed. This was achieved by serial passage of pneumococci, separately, in mouse models of nasopharyngeal carriage or pneumonia. Passaged pneumococci became more effective colonizers of the respiratory tract and we observed several examples of potential parallel evolution. The cell wall-modifying glycosyltransferase LafA was under strong selection during lung passage, whereas the surface expressed pneumococcal vaccine antigen gene pvaA and the glycerol-3-phosphate dehydrogenase gene gpsA were frequent targets of mutation in nasopharynx-passaged pneumococci. These mutations were not identified in pneumococci that were separately evolved by serial passage on laboratory agar. We focused on gpsA, in which the same single nucleotide polymorphism arose in two independently evolved nasopharynx-passaged lineages. We describe a new role for this gene in nasopharyngeal carriage and show that the identified single nucleotide change confers resistance to oxidative stress and enhanced nasopharyngeal colonization potential. We demonstrate that polymorphisms in gpsA arise and are retained during human colonization. These findings highlight how within-host environmental conditions can determine trajectories of bacterial evolution. Relative invasiveness or attack rate of pneumococcal lineages may be defined by genes that make niche-specific contributions to bacterial fitness. Experimental evolution in animal infection models is a powerful tool to investigate the relative roles played by pathogen virulence and colonization factors within different host niches.
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Affiliation(s)
- Angharad E Green
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Deborah Howarth
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Chrispin Chaguza
- Parasites and Microbes Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, United Kingdom
| | - Haley Echlin
- Department of Infectious Disease, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - R Frèdi Langendonk
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Connor Munro
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Thomas E Barton
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Jay C D Hinton
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Stephen D Bentley
- Parasites and Microbes Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, United Kingdom
| | - Jason W Rosch
- Department of Infectious Disease, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Daniel R Neill
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
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23
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Solano-Collado V, Ruiz-Cruz S, Lorenzo-Díaz F, Pluta R, Espinosa M, Bravo A. Recognition of Streptococcal Promoters by the Pneumococcal SigA Protein. Front Mol Biosci 2021; 8:666504. [PMID: 34250014 PMCID: PMC8264293 DOI: 10.3389/fmolb.2021.666504] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 06/14/2021] [Indexed: 11/13/2022] Open
Abstract
Promoter recognition by RNA polymerase is a key step in the regulation of gene expression. The bacterial RNA polymerase core enzyme is a complex of five subunits that interacts transitory with one of a set of sigma factors forming the RNA polymerase holoenzyme. The sigma factor confers promoter specificity to the RNA polymerase. In the Gram-positive pathogenic bacterium Streptococcus pneumoniae, most promoters are likely recognized by SigA, a poorly studied housekeeping sigma factor. Here we present a sequence conservation analysis and show that SigA has similar protein architecture to Escherichia coli and Bacillus subtilis homologs, namely the poorly conserved N-terminal 100 residues and well-conserved rest of the protein (domains 2, 3, and 4). Further, we have purified the native (untagged) SigA protein encoded by the pneumococcal R6 strain and reconstituted an RNA polymerase holoenzyme composed of the E. coli core enzyme and the sigma factor SigA (RNAP-SigA). By in vitro transcription, we have found that RNAP-SigA was able to recognize particular promoters, not only from the pneumococcal chromosome but also from the S. agalactiae promiscuous antibiotic-resistance plasmid pMV158. Specifically, SigA was able to direct the RNA polymerase to transcribe genes involved in replication and conjugative mobilization of plasmid pMV158. Our results point to the versatility of SigA in promoter recognition and its contribution to the promiscuity of plasmid pMV158.
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Affiliation(s)
| | - Sofía Ruiz-Cruz
- School of Microbiology, University College Cork, Cork, Ireland
| | - Fabián Lorenzo-Díaz
- Departamento de Bioquímica, Microbiología, Biología Celular y Genética, Universidad de La Laguna, Tenerife, Spain
| | - Radoslaw Pluta
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Manuel Espinosa
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Alicia Bravo
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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24
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Carbon Source-Dependent Changes of the Structure of Streptococcus pneumoniae Capsular Polysaccharide with Serotype 6F. Int J Mol Sci 2021; 22:ijms22094580. [PMID: 33925509 PMCID: PMC8123889 DOI: 10.3390/ijms22094580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/21/2021] [Accepted: 04/22/2021] [Indexed: 11/30/2022] Open
Abstract
The structure of the exopolysaccharide capsule of Streptococcus pneumoniae is defined by the genetic arrangement of the capsule operon allowing the unequivocal identification of the pneumococcal serotype. Here, we investigated the environment-dependent composition of the polysaccharide structure of S. pneumoniae serotype 6F. When grown in a chemically defined medium (CDM) with glucose versus galactose, the exopolysaccharide capsule of the serotype 6F strains reveals a ratio of 1/0.6 or 1/0.3 for galactose/glucose in the capsule by 1H-NMR analyses, respectively. Increased production of the capsule precursor UDP-glucose has been identified by 31P-NMR in CDM with glucose. Flow cytometric experiments using monoclonal antibodies showed decreased labelling of Hyp6AG4 (specific for serotype 6A) antibodies when 6F is grown in glucose as compared to galactose, which mirrors the 1H-NMR results. Whole-genome sequencing analyses of serotype 6F isolates suggested that the isolates evolved during two different events from serotype 6A during the time when the 13-valent pneumococcal conjugate vaccine (PCV-13) was introduced. In conclusion, this study shows differences in the capsular structure of serotype 6F strains using glucose as compared to galactose as the carbon source. Therefore, 6F strains may show slightly different polysaccharide composition while colonizing the human nasopharynx (galactose rich) as compared to invasive locations such as the blood (glucose rich).
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25
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Interactions of the Streptococcus pneumoniae Toxin-Antitoxin RelBE Proteins with Their Target DNA. Microorganisms 2021; 9:microorganisms9040851. [PMID: 33921033 PMCID: PMC8071376 DOI: 10.3390/microorganisms9040851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 11/17/2022] Open
Abstract
Type II bacterial toxin-antitoxin (TA) systems are found in most bacteria, archaea, and mobile genetic elements. TAs are usually found as a bi-cistronic operon composed of an unstable antitoxin and a stable toxin that targets crucial cellular functions like DNA supercoiling, cell-wall synthesis or mRNA translation. The type II RelBE system encoded by the pathogen Streptococcus pneumoniae is highly conserved among different strains and participates in biofilm formation and response to oxidative stress. Here, we have analyzed the participation of the RelB antitoxin and the RelB:RelE protein complex in the self-regulation of the pneumococcal relBE operon. RelB acted as a weak repressor, whereas RelE performed the role of a co-repressor. By DNA footprinting experiments, we show that the proteins bind to a region that encompasses two palindromic sequences that are located around the -10 sequences of the single promoter that directs the synthesis of the relBE mRNA. High-resolution footprinting assays showed the distribution of bases whose deoxyriboses are protected by the bound proteins, demonstrating that RelB and RelB:RelE contacted the DNA backbone on one face of the DNA helix and that these interactions extended beyond the palindromic sequences. Our findings suggest that the binding of the RelBE proteins to its DNA target would lead to direct inhibition of the binding of the host RNA polymerase to the relBE promoter.
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26
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Gerovac M, Vogel J, Smirnov A. The World of Stable Ribonucleoproteins and Its Mapping With Grad-Seq and Related Approaches. Front Mol Biosci 2021; 8:661448. [PMID: 33898526 PMCID: PMC8058203 DOI: 10.3389/fmolb.2021.661448] [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] [Received: 01/30/2021] [Accepted: 03/04/2021] [Indexed: 12/13/2022] Open
Abstract
Macromolecular complexes of proteins and RNAs are essential building blocks of cells. These stable supramolecular particles can be viewed as minimal biochemical units whose structural organization, i.e., the way the RNA and the protein interact with each other, is directly linked to their biological function. Whether those are dynamic regulatory ribonucleoproteins (RNPs) or integrated molecular machines involved in gene expression, the comprehensive knowledge of these units is critical to our understanding of key molecular mechanisms and cell physiology phenomena. Such is the goal of diverse complexomic approaches and in particular of the recently developed gradient profiling by sequencing (Grad-seq). By separating cellular protein and RNA complexes on a density gradient and quantifying their distributions genome-wide by mass spectrometry and deep sequencing, Grad-seq charts global landscapes of native macromolecular assemblies. In this review, we propose a function-based ontology of stable RNPs and discuss how Grad-seq and related approaches transformed our perspective of bacterial and eukaryotic ribonucleoproteins by guiding the discovery of new RNA-binding proteins and unusual classes of noncoding RNAs. We highlight some methodological aspects and developments that permit to further boost the power of this technique and to look for exciting new biology in understudied and challenging biological models.
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Affiliation(s)
- Milan Gerovac
- Institute of Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany
| | - Jörg Vogel
- Institute of Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
| | - Alexandre Smirnov
- UMR 7156—Génétique Moléculaire, Génomique, Microbiologie (GMGM), University of Strasbourg, CNRS, Strasbourg, France
- University of Strasbourg Institute for Advanced Study (USIAS), Strasbourg, France
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27
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Eichner H, Karlsson J, Spelmink L, Pathak A, Sham LT, Henriques-Normark B, Loh E. RNA thermosensors facilitate Streptococcus pneumoniae and Haemophilus influenzae immune evasion. PLoS Pathog 2021; 17:e1009513. [PMID: 33914847 PMCID: PMC8084184 DOI: 10.1371/journal.ppat.1009513] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 03/29/2021] [Indexed: 11/18/2022] Open
Abstract
Bacterial meningitis is a major cause of death and disability in children worldwide. Two human restricted respiratory pathogens, Streptococcus pneumoniae and Haemophilus influenzae, are the major causative agents of bacterial meningitis, attributing to 200,000 deaths annually. These pathogens are often part of the nasopharyngeal microflora of healthy carriers. However, what factors elicit them to disseminate and cause invasive diseases, remain unknown. Elevated temperature and fever are hallmarks of inflammation triggered by infections and can act as warning signals to pathogens. Here, we investigate whether these respiratory pathogens can sense environmental temperature to evade host complement-mediated killing. We show that productions of two vital virulence factors and vaccine components, the polysaccharide capsules and factor H binding proteins, are temperature dependent, thus influencing serum/opsonophagocytic killing of the bacteria. We identify and characterise four novel RNA thermosensors in S. pneumoniae and H. influenzae, responsible for capsular biosynthesis and production of factor H binding proteins. Our data suggest that these bacteria might have independently co-evolved thermosensing abilities with different RNA sequences but distinct secondary structures to evade the immune system.
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Affiliation(s)
- Hannes Eichner
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - Jens Karlsson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - Laura Spelmink
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - Anuj Pathak
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - Lok-To Sham
- Infectious Disease Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Birgitta Henriques-Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
- Clinical Microbiology, Bioclinicum, Karolinska University Hospital, Solna, Sweden
- Lee Kong Chian School of Medicine and Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Edmund Loh
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
- Clinical Microbiology, Bioclinicum, Karolinska University Hospital, Solna, Sweden
- Lee Kong Chian School of Medicine and Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
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28
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Sanchez-Rosario Y, Johnson MDL. Media Matters, Examining Historical and Modern Streptococcus pneumoniae Growth Media and the Experiments They Affect. Front Cell Infect Microbiol 2021; 11:613623. [PMID: 33834003 PMCID: PMC8021847 DOI: 10.3389/fcimb.2021.613623] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 03/02/2021] [Indexed: 12/18/2022] Open
Abstract
While some bacteria can thrive for generations in minerals and salts, many require lavish nutrition and specific chemicals to survive to the point where they can be observed and researched. Although researchers once boiled and rendered animal flesh and bones to obtain a media that facilitated bacterial growth, we now have a plethora of formulations and manufacturers to provide dehydrated flavors of historical, modified, and modern media. The purpose of media has evolved from simple isolation to more measured study. However, in some instances, media formulated to aid the metabolic, nutritional, or physical properties of microbes may not be best suited for studying pathogen behavior or resilience as a function of host interactions. While there have been comparative studies on handfuls of these media in Streptococcus pneumoniae, this review focuses on describing both the historical and modern composition of common complex (Todd Hewitt and M17), semi-defined (Adams and Roe), and defined pneumococcal media (RPMI and Van de Rijn and Kessler), key components discovered/needed for cultivation/growth enhancement, and effects these different media have on bacterial phenotypes and experimental outcomes. While many researchers find the best conditions to grow and experiment on their bacteria of choice, the reasons for some researchers to use a specific medium is at best, not discussed, and at worst, arbitrary. As such, the goal of this review is to highlight the differences in pneumococcal media to encourage investigators to challenge their decisions on why they use a given medium, discuss the recipe, and explain their reasoning.
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Affiliation(s)
| | - Michael D L Johnson
- Department of Immunobiology, University of Arizona, Tucson, AZ, United States.,BIO5 Institute, University of Arizona, Tucson, AZ, United States.,Valley Fever Center for Excellence, University of Arizona, Tucson, AZ, United States
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29
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Fuji N, Pichichero ME, Kaur R. Comparison of specific in-vitro virulence gene expression and innate host response in locally invasive vs colonizer strains of Streptococcus pneumoniae. Med Microbiol Immunol 2021; 210:111-120. [PMID: 33751214 DOI: 10.1007/s00430-021-00701-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 02/27/2021] [Indexed: 10/21/2022]
Abstract
Among Rochester NY children, a dramatic increase in nasopharyngeal (NP) colonization by non-vaccine pneumococcal serotypes 35B and 15A occurred during years 2010-2015, after introduction of 13-valent pneumococcal conjugate vaccine (PCV13). In our population, serotype 35B strains colonized in the nasopharynx (NP) but infrequently caused acute otitis media (AOM) whereas serotype 15A strains displayed virulence, evidenced by causing AOM. To explain the virulence difference, virulence genes expression between 35B and 15A, as well as the host's immune response during asymptomatic colonization were analyzed. We investigated differences in regulation of 19 virulence genes for differences in virulence using RT-PCR in 20 35B and 14 15A strains and measured gene expression of 9 host innate cytokines in the NP to assess the mucosal inflammatory response during asymptomatic colonization. Comparing 35B versus 15A strains, genes for competence ComA and RrgC were upregulated; capsular (Cps2D) and virulence genes (PfbA, PcpA and PhtE) were downregulated among 35B strains. PavB, LytA, LytB, NanA, CiaR, PhtD, LuxS, PspA and pneumolysin (Ply) showed no difference. IL17 and IL23 gene expression were > tenfold higher during 35B compared to 15A strain asymptomatic colonization. Only IL23 showed significant difference. In the first 5 years after introduction of PCV13, serotype 35B strains emerged as asymptomatic colonizers and 15A strains emerged to cause AOM in young children. Various genes (PfbA, PcpA, Cps2D and PhtE) among tested in this analysis were downregulated in 35B whereas ComA and RrgC were significantly upregulated. For the host's cytokine response, IL23 proinflammatory response which is essential for the differentiation of Th17 lymphocytes in the NP of children with 35B strains was significantly higher than the response to 15A during asymptomatic colonization.
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Affiliation(s)
- Naoko Fuji
- Center for Infectious Diseases and Immunology, Rochester General Hospital Research Institute, Rochester General Hospital, 1425 Portland Avenue, Rochester, NY, 14621, USA
| | - Michael E Pichichero
- Center for Infectious Diseases and Immunology, Rochester General Hospital Research Institute, Rochester General Hospital, 1425 Portland Avenue, Rochester, NY, 14621, USA
| | - Ravinder Kaur
- Center for Infectious Diseases and Immunology, Rochester General Hospital Research Institute, Rochester General Hospital, 1425 Portland Avenue, Rochester, NY, 14621, USA.
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30
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Hirschmann S, Gómez-Mejia A, Mäder U, Karsunke J, Driesch D, Rohde M, Häussler S, Burchhardt G, Hammerschmidt S. The Two-Component System 09 Regulates Pneumococcal Carbohydrate Metabolism and Capsule Expression. Microorganisms 2021; 9:microorganisms9030468. [PMID: 33668344 PMCID: PMC7996280 DOI: 10.3390/microorganisms9030468] [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: 01/01/2021] [Revised: 02/09/2021] [Accepted: 02/22/2021] [Indexed: 02/05/2023] Open
Abstract
Streptococcus pneumoniae two-component regulatory systems (TCSs) are important systems that perceive and respond to various host environmental stimuli. In this study, we have explored the role of TCS09 on gene expression and phenotypic alterations in S. pneumoniae D39. Our comparative transcriptomic analyses identified 67 differently expressed genes in total. Among those, agaR and the aga operon involved in galactose metabolism showed the highest changes. Intriguingly, the encapsulated and nonencapsulated hk09-mutants showed significant growth defects under nutrient-defined conditions, in particular with galactose as a carbon source. Phenotypic analyses revealed alterations in the morphology of the nonencapsulated hk09- and tcs09-mutants, whereas the encapsulated hk09- and tcs09-mutants produced higher amounts of capsule. Interestingly, the encapsulated D39∆hk09 showed only the opaque colony morphology, while the D39∆rr09- and D39∆tcs09-mutants had a higher proportion of transparent variants. The phenotypic variations of D39ΔcpsΔhk09 and D39ΔcpsΔtcs09 are in accordance with their higher numbers of outer membrane vesicles, higher sensitivity against Triton X-100 induced autolysis, and lower resistance against oxidative stress. In conclusion, these results indicate the importance of TCS09 for pneumococcal metabolic fitness and resistance against oxidative stress by regulating the carbohydrate metabolism and thereby, most likely indirectly, the cell wall integrity and amount of capsular polysaccharide.
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Affiliation(s)
- Stephanie Hirschmann
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, 17487 Greifswald, Germany; (S.H.); (A.G.-M.); (J.K.); (G.B.)
| | - Alejandro Gómez-Mejia
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, 17487 Greifswald, Germany; (S.H.); (A.G.-M.); (J.K.); (G.B.)
| | - Ulrike Mäder
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University Medicine Greifswald, 17475 Greifswald, Germany;
| | - Julia Karsunke
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, 17487 Greifswald, Germany; (S.H.); (A.G.-M.); (J.K.); (G.B.)
| | | | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany;
| | - Susanne Häussler
- Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany;
| | - Gerhard Burchhardt
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, 17487 Greifswald, Germany; (S.H.); (A.G.-M.); (J.K.); (G.B.)
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, 17487 Greifswald, Germany; (S.H.); (A.G.-M.); (J.K.); (G.B.)
- Correspondence:
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31
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Li Q, Cebrián R, Montalbán-López M, Ren H, Wu W, Kuipers OP. Outer-membrane-acting peptides and lipid II-targeting antibiotics cooperatively kill Gram-negative pathogens. Commun Biol 2021; 4:31. [PMID: 33398076 PMCID: PMC7782785 DOI: 10.1038/s42003-020-01511-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 11/11/2020] [Indexed: 02/08/2023] Open
Abstract
The development and dissemination of antibiotic-resistant bacterial pathogens is a growing global threat to public health. Novel compounds and/or therapeutic strategies are required to face the challenge posed, in particular, by Gram-negative bacteria. Here we assess the combined effect of potent cell-wall synthesis inhibitors with either natural or synthetic peptides that can act on the outer-membrane. Thus, several linear peptides, either alone or combined with vancomycin or nisin, were tested against selected Gram-negative pathogens, and the best one was improved by further engineering. Finally, peptide D-11 and vancomycin displayed a potent antimicrobial activity at low μM concentrations against a panel of relevant Gram-negative pathogens. This combination was highly active in biological fluids like blood, but was non-hemolytic and non-toxic against cell lines. We conclude that vancomycin and D-11 are safe at >50-fold their MICs. Based on the results obtained, and as a proof of concept for the newly observed synergy, a Pseudomonas aeruginosa mouse infection model experiment was also performed, showing a 4 log10 reduction of the pathogen after treatment with the combination. This approach offers a potent alternative strategy to fight (drug-resistant) Gram-negative pathogens in humans and mammals.
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Affiliation(s)
- Qian Li
- grid.4830.f0000 0004 0407 1981Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands ,grid.34418.3a0000 0001 0727 9022Present Address: State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, 430062 Wuhan, China
| | - Rubén Cebrián
- grid.4830.f0000 0004 0407 1981Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Manuel Montalbán-López
- grid.4830.f0000 0004 0407 1981Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands ,grid.4489.10000000121678994Present Address: Department of Microbiology, Faculty of Sciences, University of Granada, Av. Fuentenueva s/n, 18071 Granada, Spain
| | - Huan Ren
- grid.216938.70000 0000 9878 7032State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, 30071 Tianjin, China
| | - Weihui Wu
- grid.216938.70000 0000 9878 7032State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, 30071 Tianjin, China
| | - Oscar P. Kuipers
- grid.4830.f0000 0004 0407 1981Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
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32
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D'Mello A, Riegler AN, Martínez E, Beno SM, Ricketts TD, Foxman EF, Orihuela CJ, Tettelin H. An in vivo atlas of host-pathogen transcriptomes during Streptococcus pneumoniae colonization and disease. Proc Natl Acad Sci U S A 2020; 117:33507-33518. [PMID: 33318198 PMCID: PMC7777036 DOI: 10.1073/pnas.2010428117] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Streptococcus pneumoniae (Spn) colonizes the nasopharynx and can cause pneumonia. From the lungs it spreads to the bloodstream and causes organ damage. We characterized the in vivo Spn and mouse transcriptomes within the nasopharynx, lungs, blood, heart, and kidneys using three Spn strains. We identified Spn genes highly expressed at all anatomical sites and in an organ-specific manner; highly expressed genes were shown to have vital roles with knockout mutants. The in vivo bacterial transcriptome during colonization/disease was distinct from previously reported in vitro transcriptomes. Distinct Spn and host gene-expression profiles were observed during colonization and disease states, revealing specific genes/operons whereby Spn adapts to and influences host sites in vivo. We identified and experimentally verified host-defense pathways induced by Spn during invasive disease, including proinflammatory responses and the interferon response. These results shed light on the pathogenesis of Spn and identify therapeutic targets.
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Affiliation(s)
- Adonis D'Mello
- Department of Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Ashleigh N Riegler
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Eriel Martínez
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Sarah M Beno
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Tiffany D Ricketts
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Ellen F Foxman
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT 06520
| | - Carlos J Orihuela
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Hervé Tettelin
- Department of Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201;
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33
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The Many Roles of the Bacterial Second Messenger Cyclic di-AMP in Adapting to Stress Cues. J Bacteriol 2020; 203:JB.00348-20. [PMID: 32839175 DOI: 10.1128/jb.00348-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Bacteria respond to changes in environmental conditions through adaptation to external cues. Frequently, bacteria employ nucleotide signaling molecules to mediate a specific, rapid response. Cyclic di-AMP (c-di-AMP) was recently discovered to be a bacterial second messenger that is essential for viability in many species. In this review, we highlight recent work that has described the roles of c-di-AMP in bacterial responses to various stress conditions. These studies show that depending on the lifestyle and environmental niche of the bacterial species, the c-di-AMP signaling network results in diverse outcomes, such as regulating osmolyte transport, controlling plant attachment, or providing a checkpoint for spore formation. c-di-AMP achieves this signaling specificity through expression of different classes of synthesis and catabolic enzymes as well as receptor proteins and RNAs, which will be summarized.
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34
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Neville SL, Eijkelkamp BA, Lothian A, Paton JC, Roberts BR, Rosch JW, McDevitt CA. Cadmium stress dictates central carbon flux and alters membrane composition in Streptococcus pneumoniae. Commun Biol 2020; 3:694. [PMID: 33214631 PMCID: PMC7678824 DOI: 10.1038/s42003-020-01417-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 10/23/2020] [Indexed: 12/12/2022] Open
Abstract
Metal ion homeostasis is essential for all forms of life. However, the breadth of intracellular impacts that arise upon dysregulation of metal ion homeostasis remain to be elucidated. Here, we used cadmium, a non-physiological metal ion, to investigate how the bacterial pathogen, Streptococcus pneumoniae, resists metal ion stress and dyshomeostasis. By combining transcriptomics, metabolomics and metalloproteomics, we reveal that cadmium stress dysregulates numerous essential cellular pathways including central carbon metabolism, lipid membrane biogenesis and homeostasis, and capsule production at the transcriptional and/or functional level. Despite the breadth of cellular pathways susceptible to metal intoxication, we show that S. pneumoniae is able to maintain viability by utilizing cellular pathways that are predominately metal-independent, such as the pentose phosphate pathway to maintain energy production. Collectively, this work provides insight into the cellular processes impacted by cadmium and how resistance to metal ion toxicity is achieved in S. pneumoniae. Neville et al. investigate how Streptococcus pneumoniae mitigates metal ion stress. Despite cadmium induced dysregulation of central carbon metabolism and lipid membrane homeostasis, they find that S. pneumoniae can remain viable by selectively utilizing predominately metal-independent cellular pathways. This study provides insights into how bacteria overcome metal ion toxicity.
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Affiliation(s)
- Stephanie L Neville
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia.
| | - Bart A Eijkelkamp
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Amber Lothian
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - James C Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA, Australia
| | - Blaine R Roberts
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.,Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Jason W Rosch
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Christopher A McDevitt
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia.
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35
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Johnston CH, Soulet AL, Bergé M, Prudhomme M, De Lemos D, Polard P. The alternative sigma factor σ X mediates competence shut-off at the cell pole in Streptococcus pneumoniae. eLife 2020; 9:62907. [PMID: 33135635 PMCID: PMC7665891 DOI: 10.7554/elife.62907] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 10/31/2020] [Indexed: 12/22/2022] Open
Abstract
Competence is a widespread bacterial differentiation program driving antibiotic resistance and virulence in many pathogens. Here, we studied the spatiotemporal localization dynamics of the key regulators that master the two intertwined and transient transcription waves defining competence in Streptococcus pneumoniae. The first wave relies on the stress-inducible phosphorelay between ComD and ComE proteins, and the second on the alternative sigma factor σX, which directs the expression of the DprA protein that turns off competence through interaction with phosphorylated ComE. We found that ComD, σX and DprA stably co-localize at one pole in competent cells, with σX physically conveying DprA next to ComD. Through this polar DprA targeting function, σX mediates the timely shut-off of the pneumococcal competence cycle, preserving cell fitness. Altogether, this study unveils an unprecedented role for a transcription σ factor in spatially coordinating the negative feedback loop of its own genetic circuit.
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Affiliation(s)
- Calum Hg Johnston
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM ; UMR5100), Centre de Biologie Intégrative (CBI), Centre Nationale de la Recherche Scientifique (CNRS), Toulouse, France.,Université Paul Sabatier (Toulouse III), Toulouse, France
| | - Anne-Lise Soulet
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM ; UMR5100), Centre de Biologie Intégrative (CBI), Centre Nationale de la Recherche Scientifique (CNRS), Toulouse, France.,Université Paul Sabatier (Toulouse III), Toulouse, France
| | - Matthieu Bergé
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM ; UMR5100), Centre de Biologie Intégrative (CBI), Centre Nationale de la Recherche Scientifique (CNRS), Toulouse, France.,Université Paul Sabatier (Toulouse III), Toulouse, France.,Dept. Microbiology and Molecular Medicine, Institute of Genetics & Genomics in Geneva (iGE3), Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Marc Prudhomme
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM ; UMR5100), Centre de Biologie Intégrative (CBI), Centre Nationale de la Recherche Scientifique (CNRS), Toulouse, France.,Université Paul Sabatier (Toulouse III), Toulouse, France
| | - David De Lemos
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM ; UMR5100), Centre de Biologie Intégrative (CBI), Centre Nationale de la Recherche Scientifique (CNRS), Toulouse, France.,Université Paul Sabatier (Toulouse III), Toulouse, France
| | - Patrice Polard
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM ; UMR5100), Centre de Biologie Intégrative (CBI), Centre Nationale de la Recherche Scientifique (CNRS), Toulouse, France.,Université Paul Sabatier (Toulouse III), Toulouse, France
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36
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Abstract
Gram-positive bacteria employ an array of secreted peptides to control population-level behaviors in response to environmental cues. We review mechanistic and functional features of secreted peptides produced by the human pathogen Streptococcus pneumoniae. We discuss sequence features, mechanisms of transport, and receptors for 3 major categories of small peptides: the double-glycine peptides, the Rap, Rgg, NprR, PlcR, and PrgX (RRNPP)-binding peptides, and the lanthionine-containing peptides. We highlight the impact of factors that contribute to carriage and pathogenesis, specifically genetic diversity, microbial competition, biofilm development, and environmental adaptation. A recent expansion in pneumococcal peptide studies reveals a complex network of interacting signaling systems where multiple peptides are integrated into the same signaling pathway, allowing multiple points of entry into the pathway and extending information content in new directions. In addition, since peptides are present in the extracellular milieu, there are opportunities for crosstalk, quorum sensing (QS), as well as intra- and interstrain and species interactions. Knowledge on the manner that population-level behaviors contribute to disease provides an avenue for the design and development of anti-infective strategies.
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37
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Liu X, Kimmey JM, Matarazzo L, de Bakker V, Van Maele L, Sirard JC, Nizet V, Veening JW. Exploration of Bacterial Bottlenecks and Streptococcus pneumoniae Pathogenesis by CRISPRi-Seq. Cell Host Microbe 2020; 29:107-120.e6. [PMID: 33120116 DOI: 10.1016/j.chom.2020.10.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 08/27/2020] [Accepted: 09/29/2020] [Indexed: 02/07/2023]
Abstract
Streptococcus pneumoniae is an opportunistic human pathogen that causes invasive diseases, including pneumonia, with greater health risks upon influenza A virus (IAV) co-infection. To facilitate pathogenesis studies in vivo, we developed an inducible CRISPR interference system that enables genome-wide fitness testing in one sequencing step (CRISPRi-seq). We applied CRISPRi-seq to assess bottlenecks and identify pneumococcal genes important in a murine pneumonia model. A critical bottleneck occurs at 48 h with few bacteria causing systemic infection. This bottleneck is not present during IAV superinfection, facilitating identification of pneumococcal pathogenesis-related genes. Top in vivo essential genes included purA, encoding adenylsuccinate synthetase, and the cps operon required for capsule production. Surprisingly, CRISPRi-seq indicated no fitness-related role for pneumolysin during superinfection. Interestingly, although metK (encoding S-adenosylmethionine synthetase) was essential in vitro, it was dispensable in vivo. This highlights advantages of CRISPRi-seq over transposon-based genetic screens, as all genes, including essential genes, can be tested for pathogenesis potential.
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Affiliation(s)
- Xue Liu
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | - Jacqueline M Kimmey
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, CA, USA; Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Laura Matarazzo
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Vincent de Bakker
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | - Laurye Van Maele
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Jean-Claude Sirard
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Victor Nizet
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, CA, USA; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland.
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38
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Synthetic gene-regulatory networks in the opportunistic human pathogen Streptococcus pneumoniae. Proc Natl Acad Sci U S A 2020; 117:27608-27619. [PMID: 33087560 PMCID: PMC7959565 DOI: 10.1073/pnas.1920015117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Streptococcus pneumoniae is a major human pathogen responsible for enormous global morbidity and mortality. Despite this, the pneumococcus makes up part of the commensal nasopharyngeal flora. How the pneumococcus switches from this commensal to pathogenic state and causes disease is unclear and very likely involves variability in expression of its virulence factors. Here, we used synthetic biology approaches to generate complex gene-regulatory networks such as logic gates and toggle switches. We show that these networks are functional in vivo to control capsule production in an influenza-superinfection model. This opens the field of systematically testing the role of phenotypic variation in pneumococcal virulence. The approaches used here may serve as an example for synthetic biology projects in unrelated organisms. Streptococcus pneumoniae can cause disease in various human tissues and organs, including the ear, the brain, the blood, and the lung, and thus in highly diverse and dynamic environments. It is challenging to study how pneumococci control virulence factor expression, because cues of natural environments and the presence of an immune system are difficult to simulate in vitro. Here, we apply synthetic biology methods to reverse-engineer gene expression control in S. pneumoniae. A selection platform is described that allows for straightforward identification of transcriptional regulatory elements out of combinatorial libraries. We present TetR- and LacI-regulated promoters that show expression ranges of four orders of magnitude. Based on these promoters, regulatory networks of higher complexity are assembled, such as logic AND gates and IMPLY gates. We demonstrate single-copy genome-integrated toggle switches that give rise to bimodal population distributions. The tools described here can be used to mimic complex expression patterns, such as the ones found for pneumococcal virulence factors. Indeed, we were able to rewire gene expression of the capsule operon, the main pneumococcal virulence factor, to be externally inducible (YES gate) or to act as an IMPLY gate (only expressed in absence of inducer). Importantly, we demonstrate that these synthetic gene-regulatory networks are functional in an influenza A virus superinfection murine model of pneumonia, paving the way for in vivo investigations of the importance of gene expression control on the pathogenicity of S. pneumoniae.
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39
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Inniss NL, Morrison DA. ComWΔ6 Stimulates Transcription of Pneumococcal Competence Genes in vitro. Front Mol Biosci 2020; 7:61. [PMID: 32435654 PMCID: PMC7218084 DOI: 10.3389/fmolb.2020.00061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 03/24/2020] [Indexed: 11/28/2022] Open
Abstract
The alternative streptococcal σ-factor and master competence regulator, σX, stimulates transcription from competence promoters, in vitro. As the only known alternative σ-factor in streptococci, σX expression is tightly controlled in each species and has a specific physiological role. Pneumococcal transformation also requires the DNA binding activity of ComW, a known σX activator and stabilizer. Mutations to the housekeeping σ factor, σA, partially alleviate the ComW requirement, suggesting that ComW is a key player in the σ factor swap during the pneumococcal competence response. However, there is no evidence of a direct ComW - RNA polymerase interaction. Furthermore, if and how ComW functions directly at combox promoters is still unknown. Here we report that a DNA-binding ComW variant, ComΔ6, can stimulate transcription from σX promoters in vitro.
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Affiliation(s)
| | - Donald A. Morrison
- Department of Biological Sciences, The University of Illinois at Chicago, Chicago, IL, United States
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40
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Hör J, Garriss G, Di Giorgio S, Hack LM, Vanselow JT, Förstner KU, Schlosser A, Henriques-Normark B, Vogel J. Grad-seq in a Gram-positive bacterium reveals exonucleolytic sRNA activation in competence control. EMBO J 2020; 39:e103852. [PMID: 32227509 PMCID: PMC7196914 DOI: 10.15252/embj.2019103852] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 03/03/2020] [Accepted: 03/06/2020] [Indexed: 12/20/2022] Open
Abstract
RNA–protein interactions are the crucial basis for many steps of bacterial gene expression, including post‐transcriptional control by small regulatory RNAs (sRNAs). In stark contrast to recent progress in the analysis of Gram‐negative bacteria, knowledge about RNA–protein complexes in Gram‐positive species remains scarce. Here, we used the Grad‐seq approach to draft a comprehensive landscape of such complexes in Streptococcus pneumoniae, in total determining the sedimentation profiles of ~ 88% of the transcripts and ~ 62% of the proteins of this important human pathogen. Analysis of in‐gradient distributions and subsequent tag‐based protein capture identified interactions of the exoribonuclease Cbf1/YhaM with sRNAs that control bacterial competence for DNA uptake. Unexpectedly, the nucleolytic activity of Cbf1 stabilizes these sRNAs, thereby promoting their function as repressors of competence. Overall, these results provide the first RNA/protein complexome resource of a Gram‐positive species and illustrate how this can be utilized to identify new molecular factors with functions in RNA‐based regulation of virulence‐relevant pathways.
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Affiliation(s)
- Jens Hör
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Geneviève Garriss
- Department of Microbiology, Tumor & Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Silvia Di Giorgio
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany.,ZB MED-Information Centre for Life Sciences, Cologne, Germany
| | - Lisa-Marie Hack
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
| | - Jens T Vanselow
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Konrad U Förstner
- ZB MED-Information Centre for Life Sciences, Cologne, Germany.,Faculty of Information Science and Communication Studies, TH Köln, Cologne, Germany
| | - Andreas Schlosser
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Birgitta Henriques-Normark
- Department of Microbiology, Tumor & Cell Biology, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden.,SCELSE and LKC, Nanyang Technological University, NTU, Singapore, Singapore
| | - Jörg Vogel
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany.,Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
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41
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Jensen CS, Norsigian CJ, Fang X, Nielsen XC, Christensen JJ, Palsson BO, Monk JM. Reconstruction and Validation of a Genome-Scale Metabolic Model of Streptococcus oralis (iCJ415), a Human Commensal and Opportunistic Pathogen. Front Genet 2020; 11:116. [PMID: 32194617 PMCID: PMC7063969 DOI: 10.3389/fgene.2020.00116] [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] [Received: 08/16/2019] [Accepted: 01/31/2020] [Indexed: 11/22/2022] Open
Abstract
The mitis group of streptococci (MGS) is a member of the healthy human microbiome in the oral cavity and upper respiratory tract. Troublingly, some MGS are able to escape this niche and cause infective endocarditis, a severe and devastating disease. Genome-scale models have been shown to be valuable in investigating metabolism of bacteria. Here we present the first genome-scale model, iCJ415, for Streptococcus oralis SK141. We validated the model using gene essentiality and amino acid auxotrophy data from closely related species. iCJ415 has 71-76% accuracy in predicting gene essentiality and 85% accuracy in predicting amino acid auxotrophy. Further, the phenotype of S. oralis was tested using the Biolog Phenotype microarrays, giving iCJ415 a 82% accuracy in predicting carbon sources. iCJ415 can be used to explore the metabolic differences within the MGS, and to explore the complicated metabolic interactions between different species in the human oral cavity.
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Affiliation(s)
- Christian S Jensen
- The Regional Department of Clinical Microbiology, Region Zealand, Slagelse, Denmark
| | - Charles J Norsigian
- Department of Bioengineering, University of California, San Diego, San Diego, CA, United States
| | - Xin Fang
- Department of Bioengineering, University of California, San Diego, San Diego, CA, United States
| | - Xiaohui C Nielsen
- The Regional Department of Clinical Microbiology, Region Zealand, Slagelse, Denmark
| | - Jens Jørgen Christensen
- The Regional Department of Clinical Microbiology, Region Zealand, Slagelse, Denmark.,Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Bernhard O Palsson
- Department of Bioengineering, University of California, San Diego, San Diego, CA, United States.,Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Jonathan M Monk
- Department of Bioengineering, University of California, San Diego, San Diego, CA, United States
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42
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Wang CY, Medlin JS, Nguyen DR, Disbennett WM, Dawid S. Molecular Determinants of Substrate Selectivity of a Pneumococcal Rgg-Regulated Peptidase-Containing ABC Transporter. mBio 2020; 11:e02502-19. [PMID: 32047125 PMCID: PMC7018657 DOI: 10.1128/mbio.02502-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 12/23/2019] [Indexed: 01/31/2023] Open
Abstract
Peptidase-containing ABC transporters (PCATs) are a widely distributed family of transporters which secrete double-glycine (GG) peptides. In the opportunistic pathogen Streptococcus pneumoniae (pneumococcus), the PCATs ComAB and BlpAB have been shown to secrete quorum-sensing pheromones and bacteriocins related to the competence and pneumocin pathways. Here, we describe another pneumococcal PCAT, RtgAB, encoded by the rtg locus and found intact in 17% of strains. The Rgg/SHP-like quorum-sensing system RtgR/S, which uses a peptide pheromone with a distinctive Trp-X-Trp motif, regulates expression of the rtg locus and provides a competitive fitness advantage in a mouse model of nasopharyngeal colonization. RtgAB secretes a set of coregulated rtg GG peptides. ComAB and BlpAB, which share a substrate pool, do not secrete the rtg GG peptides. Similarly, RtgAB does not efficiently secrete ComAB/BlpAB substrates. We examined the molecular determinants of substrate selectivity between ComAB, BlpAB, and RtgAB and found that the GG peptide signal sequences contain all the information necessary to direct secretion through specific transporters. Secretion through ComAB and BlpAB depends largely on the identity of four conserved hydrophobic signal sequence residues previously implicated in substrate recognition by PCATs. In contrast, a motif situated at the N-terminal end of the signal sequence, found only in rtg GG peptides, directs secretion through RtgAB. These findings illustrate the complexity in predicting substrate-PCAT pairings by demonstrating specificity that is not dictated solely by signal sequence residues previously implicated in substrate recognition.IMPORTANCE The export of peptides from the cell is a fundamental process carried out by all bacteria. One method of bacterial peptide export relies on a family of transporters called peptidase-containing ABC transporters (PCATs). PCATs export so-called GG peptides which carry out diverse functions, including cell-to-cell communication and interbacterial competition. In this work, we describe a PCAT-encoding genetic locus, rtg, in the pathogen Streptococcus pneumoniae (pneumococcus). The rtg locus is linked to increased competitive fitness advantage in a mouse model of nasopharyngeal colonization. We also describe how the rtg PCAT preferentially secretes a set of coregulated GG peptides but not GG peptides secreted by other pneumococcal PCATs. These findings illuminate a relatively understudied part of PCAT biology: how these transporters discriminate between different subsets of GG peptides. Ultimately, expanding our knowledge of PCATs will advance our understanding of the many microbial processes dependent on these transporters.
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Affiliation(s)
- Charles Y Wang
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Jennifer S Medlin
- Department of Pediatrics, University of Michigan, Ann Arbor, Michigan, USA
| | - Don R Nguyen
- Department of Pediatrics, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Suzanne Dawid
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Pediatrics, University of Michigan, Ann Arbor, Michigan, USA
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43
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Tóthpál A, Desobry K, Joshi SS, Wyllie AL, Weinberger DM. Variation of growth characteristics of pneumococcus with environmental conditions. BMC Microbiol 2019; 19:304. [PMID: 31878880 PMCID: PMC6933730 DOI: 10.1186/s12866-019-1671-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 12/02/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pneumococcus is exposed to a variety of temperature and oxygen levels in the upper respiratory tract and as it invades the lung, tissues, and blood. We sought to determine the effect of environmental variability on growth in vitro and to assess variability between strains. We evaluated the effect of temperature and oxygen on the growth of 256 isolates representing 53 serotypes, recovered from healthy carriers and disease patients. Strains were grown at a range of temperatures, anaerobically or in ambient air with catalase, and were monitored by reading the optical density. Regression models evaluated variation in the characteristics of the growth curves. RESULTS Most isolates grew to the maximal density at low temperatures (~33C) and under aerobic conditions. There was considerable variability between strains, and some of this variability was linked to serotype. However, capsule-switch experiments suggest that the production of different capsules might not be sufficient to explain this variation, suggesting there could be interactions between the capsule and genetic background. CONCLUSIONS Pneumococcal strains vary in how they respond to environmental variations, some of this variation can be explained by the capsule type being produced, but capsule production itself is not sufficient to explain the variability. This variability could help to explain why different lineages of pneumococcus are more common in carriage or disease.
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Affiliation(s)
- Adrienn Tóthpál
- Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, CT, 06510, USA. .,Institute of Medical Microbiology, Semmelweis University, Nagyvarad ter 4, Budapest, HU-1089, Hungary.
| | - Katherine Desobry
- Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, CT, 06510, USA
| | - Shreyas S Joshi
- Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, CT, 06510, USA
| | - Anne L Wyllie
- Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, CT, 06510, USA
| | - Daniel M Weinberger
- Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, CT, 06510, USA.
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44
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Domenech A, Slager J, Veening JW. Antibiotic-Induced Cell Chaining Triggers Pneumococcal Competence by Reshaping Quorum Sensing to Autocrine-Like Signaling. Cell Rep 2019; 25:2390-2400.e3. [PMID: 30485808 PMCID: PMC6289044 DOI: 10.1016/j.celrep.2018.11.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 09/22/2018] [Accepted: 10/31/2018] [Indexed: 02/06/2023] Open
Abstract
Streptococcus pneumoniae can acquire antibiotic resistance by activation of competence and subsequent DNA uptake. Here, we demonstrate that aztreonam (ATM) and clavulanic acid (CLA) promote competence. We show that both compounds induce cell chain formation by targeting the d,d-carboxypeptidase PBP3. In support of the hypothesis that chain formation promotes competence, we demonstrate that an autolysin mutant (ΔlytB) is hypercompetent. Since competence is initiated by the binding of a small extracellular peptide (CSP) to a membrane-anchored receptor (ComD), we wondered whether chain formation alters CSP diffusion kinetics. Indeed, ATM or CLA presence affects competence synchronization by shifting from global to local quorum sensing, as CSP is primarily retained to chained cells, rather than shared in a common pool. Importantly, autocrine-like signaling prolongs the time window in which the population is able to take up DNA. Together, these insights demonstrate the versatility of quorum sensing and highlight the importance of an accurate antibiotic prescription. Identification of a mechanism by which antibiotics induce competence in S. pneumoniae Antibiotics targeting penicillin-binding protein 3 promote chain formation Cell chains retain, rather than diffuse, the quorum-sensing peptide CSP Chaining populations feature a longer competence and transformation time window
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Affiliation(s)
- Arnau Domenech
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland; Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands
| | - Jelle Slager
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland; Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands.
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45
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Troxler LJ, Werren JP, Schaffner TO, Mostacci N, Vermathen P, Vermathen M, Wüthrich D, Simillion C, Brugger SD, Bruggmann R, Hathaway LJ, Furrer J, Hilty M. Carbon source regulates polysaccharide capsule biosynthesis in Streptococcus pneumoniae. J Biol Chem 2019; 294:17224-17238. [PMID: 31594867 PMCID: PMC6873171 DOI: 10.1074/jbc.ra119.010764] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 10/02/2019] [Indexed: 11/06/2022] Open
Abstract
The exopolysaccharide capsule of Streptococcus pneumoniae is an important virulence factor, but the mechanisms that regulate capsule thickness are not fully understood. Here, we investigated the effects of various exogenously supplied carbohydrates on capsule production and gene expression in several pneumococcal serotypes. Microscopy analyses indicated a near absence of the capsular polysaccharide (CPS) when S. pneumoniae was grown on fructose. Moreover, serotype 7F pneumococci produced much less CPS than strains of other serotypes (6B, 6C, 9V, 15, and 23F) when grown on glucose or sucrose. RNA-sequencing revealed carbon source-dependent regulation of distinct genes of WT strains and capsule-switch mutants of serotypes 6B and 7F, but could not explain the mechanism of capsule thickness regulation. In contrast, 31P NMR of whole-cell extract from capsule-knockout strains (Δcps) clearly revealed the accumulation or absence of capsule precursor metabolites when cells were grown on glucose or fructose, respectively. This finding suggests that fructose uptake mainly results in intracellular fructose 1-phosphate, which is not converted to CPS precursors. In addition, serotype 7F strains accumulated more precursors than did 6B strains, indicating less efficient conversion of precursor metabolites into the CPS in 7F, in line with its thinner capsule. Finally, isotopologue sucrose labeling and NMR analyses revealed that the uptake of the labeled fructose subunit into the capsule is <10% that of glucose. Our findings on the effects of carbon sources on CPS production in different S. pneumoniae serotypes may contribute to a better understanding of pneumococcal diseases and could inform future therapeutic approaches.
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Affiliation(s)
- Lukas J Troxler
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, 3001 Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Joel P Werren
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, 3001 Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Thierry O Schaffner
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, 3001 Bern, Switzerland
| | - Nadezda Mostacci
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, 3001 Bern, Switzerland
| | - Peter Vermathen
- Department of BioMedical Research and Radiology, University of Bern and Inselspital, 3012 Bern, Switzerland
| | - Martina Vermathen
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Daniel Wüthrich
- Interfaculty Bioinformatics Unit and Swiss Institute of Bioinformatics, University of Bern, 3012 Bern, Switzerland.,Applied Microbiology Research Unit, Department of Biomedicine, University of Basel, 4031 Basel, Switzerland.,Division of Clinical Microbiology, University Hospital Basel, 4031 Basel, Switzerland
| | - Cedric Simillion
- Interfaculty Bioinformatics Unit and Swiss Institute of Bioinformatics, University of Bern, 3012 Bern, Switzerland
| | - Silvio D Brugger
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, 8091 Zurich, Switzerland.,The Forsyth Institute (Microbiology), Cambridge, Massachusetts 02142.,Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts 02142
| | - Rémy Bruggmann
- Interfaculty Bioinformatics Unit and Swiss Institute of Bioinformatics, University of Bern, 3012 Bern, Switzerland
| | - Lucy J Hathaway
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, 3001 Bern, Switzerland
| | - Julien Furrer
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Markus Hilty
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, 3001 Bern, Switzerland
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46
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In vivo proteomics identifies the competence regulon and AliB oligopeptide transporter as pathogenic factors in pneumococcal meningitis. PLoS Pathog 2019; 15:e1007987. [PMID: 31356624 PMCID: PMC6687184 DOI: 10.1371/journal.ppat.1007987] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 08/08/2019] [Accepted: 07/15/2019] [Indexed: 01/09/2023] Open
Abstract
Streptococcus pneumoniae (pneumococci) is a leading cause of severe bacterial meningitis in many countries worldwide. To characterize the repertoire of fitness and virulence factors predominantly expressed during meningitis we performed niche-specific analysis of the in vivo proteome in a mouse meningitis model, in which bacteria are directly inoculated into the cerebrospinal fluid (CSF) cisterna magna. We generated a comprehensive mass spectrometry (MS) spectra library enabling bacterial proteome analysis even in the presence of eukaryotic proteins. We recovered 200,000 pneumococci from CSF obtained from meningitis mice and by MS we identified 685 pneumococci proteins in samples from in vitro filter controls and 249 in CSF isolates. Strikingly, the regulatory two-component system ComDE and substrate-binding protein AliB of the oligopeptide transporter system were exclusively detected in pneumococci recovered from the CSF. In the mouse meningitis model, AliB-, ComDE-, or AliB-ComDE-deficiency resulted in attenuated meningeal inflammation and disease severity when compared to wild-type pneumococci indicating the crucial role of ComDE and AliB in pneumococcal meningitis. In conclusion, we show here mechanisms of pneumococcal adaptation to a defined host compartment by a proteome-based approach. Further, this study provides the basis of a promising strategy for the identification of protein antigens critical for invasive disease caused by pneumococci and other meningeal pathogens. Pneumococci are one of the most common and aggressive meningitis pathogens associated with mortality rates between 10% and 30%. Due to severe complications during therapeutic intervention, prevention strategies to combat pneumococcal meningitis (PM) are preferred. The vaccines available are so far suboptimal and inefficient to prevent serious PM. Hence, deciphering the mechanisms employed by pneumococci to encounter and survive in the cerebrospinal fluid (CSF) will pave the way for the development of new antimicrobial strategies. This work used an in vivo proteome-based approach to identify pneumococcal proteins expressed in the CSF during acute meningitis. This strategy identified a nutrient uptake system and regulatory system to be highly expressed in the CSF and being crucial for PM. Knocking out two of the highly in vivo expressed proteins (AliA and ComDE) in S. pneumoniae yields to a significant increase in survival and decrease in pathogen burden of infected mice. These host compartment specific expressed pneumococcal antigens represent promising candidates for antimicrobials or protein-based vaccines.
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47
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Winkler ME, Morrison DA. Competence beyond Genes: Filling in the Details of the Pneumococcal Competence Transcriptome by a Systems Approach. J Bacteriol 2019; 201:e00238-19. [PMID: 30988030 PMCID: PMC6560134 DOI: 10.1128/jb.00238-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
DNA uptake by natural competence is a central process underlying the genetic plasticity, biology, and virulence of the human respiratory opportunistic pathogen Streptococcus pneumoniae A study reported in this issue (J. Slager, R. Aprianto, and J.-W. Veening, J. Bacteriol. 201:e00780-18, https://doi.org/10.1128/JB.00780-18) combined deep-genome annotation and high-resolution transcriptome analyses to considerably extend the previous model of temporal regulation of competence at the operon and component gene levels. That extended study also provides a playbook for updating, refining, and extending genomic data sets and making them publicly available.
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Affiliation(s)
- Malcolm E Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Donald A Morrison
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
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48
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Slager J, Aprianto R, Veening JW. Deep genome annotation of the opportunistic human pathogen Streptococcus pneumoniae D39. Nucleic Acids Res 2019; 46:9971-9989. [PMID: 30107613 PMCID: PMC6212727 DOI: 10.1093/nar/gky725] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 07/30/2018] [Indexed: 12/27/2022] Open
Abstract
A precise understanding of the genomic organization into transcriptional units and their regulation is essential for our comprehension of opportunistic human pathogens and how they cause disease. Using single-molecule real-time (PacBio) sequencing we unambiguously determined the genome sequence of Streptococcus pneumoniae strain D39 and revealed several inversions previously undetected by short-read sequencing. Significantly, a chromosomal inversion results in antigenic variation of PhtD, an important surface-exposed virulence factor. We generated a new genome annotation using automated tools, followed by manual curation, reflecting the current knowledge in the field. By combining sequence-driven terminator prediction, deep paired-end transcriptome sequencing and enrichment of primary transcripts by Cappable-Seq, we mapped 1015 transcriptional start sites and 748 termination sites. We show that the pneumococcal transcriptional landscape is complex and includes many secondary, antisense and internal promoters. Using this new genomic map, we identified several new small RNAs (sRNAs), RNA switches (including sixteen previously misidentified as sRNAs), and antisense RNAs. In total, we annotated 89 new protein-encoding genes, 34 sRNAs and 165 pseudogenes, bringing the S. pneumoniae D39 repertoire to 2146 genetic elements. We report operon structures and observed that 9% of operons are leaderless. The genome data are accessible in an online resource called PneumoBrowse (https://veeninglab.com/pneumobrowse) providing one of the most complete inventories of a bacterial genome to date. PneumoBrowse will accelerate pneumococcal research and the development of new prevention and treatment strategies.
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Affiliation(s)
- Jelle Slager
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands
| | - Rieza Aprianto
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands
| | - Jan-Willem Veening
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands.,Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
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49
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Refining the Pneumococcal Competence Regulon by RNA Sequencing. J Bacteriol 2019; 201:JB.00780-18. [PMID: 30885934 PMCID: PMC6560143 DOI: 10.1128/jb.00780-18] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 03/15/2019] [Indexed: 12/13/2022] Open
Abstract
Streptococcus pneumoniae is an opportunistic human pathogen responsible for over a million deaths every year. Although both vaccination programs and antibiotic therapies have been effective in prevention and treatment of pneumococcal infections, respectively, the sustainability of these solutions is uncertain. The pneumococcal genome is highly flexible, leading to vaccine escape and antibiotic resistance. This flexibility is predominantly facilitated by competence, a state allowing the cell to take up and integrate exogenous DNA. Thus, it is essential to obtain a detailed overview of gene expression during competence. This is stressed by the fact that administration of several classes of antibiotics can lead to competence. Previous studies on the competence regulon were performed with microarray technology and were limited to an incomplete set of known genes. Using RNA sequencing combined with an up-to-date genome annotation, we provide an updated overview of competence-regulated genes. Competence for genetic transformation allows the opportunistic human pathogen Streptococcus pneumoniae to take up exogenous DNA for incorporation into its own genome. This ability may account for the extraordinary genomic plasticity of this bacterium, leading to antigenic variation, vaccine escape, and the spread of antibiotic resistance. The competence system has been thoroughly studied, and its regulation is well understood. Additionally, over the last decade, several stress factors have been shown to trigger the competent state, leading to the activation of several stress response regulons. The arrival of next-generation sequencing techniques allowed us to update the competence regulon, the latest report on which still depended on DNA microarray technology. Enabled by the availability of an up-to-date genome annotation, including transcript boundaries, we assayed time-dependent expression of all annotated features in response to competence induction, were able to identify the affected promoters, and produced a more complete overview of the various regulons activated during the competence state. We show that 4% of all annotated genes are under direct control of competence regulators ComE and ComX, while the expression of a total of up to 17% of all genes is affected, either directly or indirectly. Among the affected genes are various small RNAs with an as-yet-unknown function. Besides the ComE and ComX regulons, we were also able to refine the CiaR, VraR (LiaR), and BlpR regulons, underlining the strength of combining transcriptome sequencing (RNA-seq) with a well-annotated genome. IMPORTANCEStreptococcus pneumoniae is an opportunistic human pathogen responsible for over a million deaths every year. Although both vaccination programs and antibiotic therapies have been effective in prevention and treatment of pneumococcal infections, respectively, the sustainability of these solutions is uncertain. The pneumococcal genome is highly flexible, leading to vaccine escape and antibiotic resistance. This flexibility is predominantly facilitated by competence, a state allowing the cell to take up and integrate exogenous DNA. Thus, it is essential to obtain a detailed overview of gene expression during competence. This is stressed by the fact that administration of several classes of antibiotics can lead to competence. Previous studies on the competence regulon were performed with microarray technology and were limited to an incomplete set of known genes. Using RNA sequencing combined with an up-to-date genome annotation, we provide an updated overview of competence-regulated genes.
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50
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Keller LE, Rueff AS, Kurushima J, Veening JW. Three New Integration Vectors and Fluorescent Proteins for Use in the Opportunistic Human Pathogen Streptococcus pneumoniae. Genes (Basel) 2019; 10:genes10050394. [PMID: 31121970 PMCID: PMC6562690 DOI: 10.3390/genes10050394] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/09/2019] [Accepted: 05/20/2019] [Indexed: 12/20/2022] Open
Abstract
Here, we describe the creation of three integration vectors, pPEPX, pPEPY and pPEPZ, for use with the opportunistic human pathogen Streptococcus pneumoniae. The constructed vectors, named PEP for Pneumococcal Engineering Platform (PEP), employ an IPTG-inducible promoter and BglBrick and BglFusion compatible multiple cloning sites allowing for fast and interchangeable cloning. PEP plasmids replicate in Escherichia coli and harbor integration sites that have homology in a large set of pneumococcal strains, including recent clinical isolates. In addition, several options of antibiotic resistance markers are available, even allowing for selection in multidrug resistant clinical isolates. The transformation efficiency of these PEP vectors as well as their ability to be expressed simultaneously was tested. Two of the three PEP vectors share homology of the integration regions with over half of the S. pneumoniae genomes examined. Transformation efficiency varied among PEP vectors based on the length of the homology regions, but all were highly transformable and can be integrated simultaneously in strain D39V. Vectors used for pneumococcal cloning are an important tool for researchers for a wide range of uses. The PEP vectors described are of particular use because they have been designed to allow for easy transfer of genes between vectors as well as integrating into transcriptionally silent areas of the chromosome. In addition, we demonstrate the successful production of several new spectrally distinct fluorescent proteins (mTurquoise2, mNeonGreen and mScarlet-I) from the PEP vectors. The PEP vectors and newly described fluorescent proteins will expand the genetic toolbox for pneumococcal researchers and aid future discoveries.
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Affiliation(s)
- Lance E Keller
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland.
| | - Anne-Stéphanie Rueff
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland.
| | - Jun Kurushima
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland.
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland.
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