1
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Lin J, Chong SY, Oh MW, Lew SQ, Zhu L, Zhang X, Witola WH, Lau GW. Signal recognition particle RNA is critical for genetic competence and virulence of Streptococcus pneumoniae. J Bacteriol 2024:e0000424. [PMID: 39171913 DOI: 10.1128/jb.00004-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 07/22/2024] [Indexed: 08/23/2024] Open
Abstract
Streptococcus pneumoniae (pneumococcus) causes a wide range of important human infectious diseases, including pneumonia, pneumonia-derived sepsis, otitis media, and meningitis. Pneumococcus produces numerous secreted proteins that are critical for normal physiology and pathogenesis. The membrane targeting and translocation of these secreted proteins are partly mediated by the signal recognition particle (SRP) complex, which consists of 4.5S small cytoplasmic RNA (ScRNA), and the Ffh, and FtsY proteins. Here, we report that pneumococcal ∆scRNA, ∆ffh, and ∆ftsY mutants were significantly impaired in competence induction, competence pili production, exogenous DNA uptake, and genetic transformation. Also, the ∆scRNA mutant was significantly attenuated in the mouse models of bacteremia and pneumonia. Interestingly, unlike the ∆scRNA, both ∆ffh and ∆ftsY mutants had growth defects on Todd-Hewitt Agar, which were alleviated by the provision of free amino acids or serum. Differences in nutritional requirements between ∆ffh and ∆ftsY vs ∆scRNA suggest that Ffh and FtsY may be partially functional in the absence of ScRNA. Finally, the insertase YidC2, which could functionally rescue some SRP mutations in other streptococcal species, was not essential for pneumococcal genetic transformation. Collectively, these results indicate that ScRNA is crucial for the successful development of genetic competence and virulence in pneumococcus. IMPORTANCE Streptococcus pneumoniae (pneumococcus) causes multiple important infectious diseases in humans. The signal recognition particle (SRP) complex, which comprised 4.5S small cytoplasmic RNA (ScRNA), and the Ffh and FtsY proteins, mediates membrane targeting and translocation of secreted proteins in all organisms. However, the role of SRP and ScRNA has not been characterized during the induction of the competence system for genetic transformation and virulence in pneumococcus. By using a combination of genetic, biochemical, proteomic, and imaging approaches, we demonstrated that the SRP complex plays a significant role in membrane targeting of competence system-regulated effectors important for genetic transformation, virulence during bacteremia and pneumonia infections, and nutritional acquisition.
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Affiliation(s)
- Jingjun Lin
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Sook Yin Chong
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Myung Whan Oh
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Shi Qian Lew
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Luchang Zhu
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Xuejin Zhang
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - William H Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Gee W Lau
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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2
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Deimel LP, Moynié L, Sun G, Lewis V, Turner A, Buchanan CJ, Burnap SA, Kutuzov M, Kobras CM, Demyaneko Y, Mohammed S, Stracy M, Struwe WB, Baldwin AJ, Naismith J, Davis BG, Sattentau QJ. Covalent penicillin-protein conjugates elicit anti-drug antibodies that are clonally and functionally restricted. Nat Commun 2024; 15:6851. [PMID: 39127707 DOI: 10.1038/s41467-024-51138-7] [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: 12/01/2023] [Accepted: 07/31/2024] [Indexed: 08/12/2024] Open
Abstract
Many archetypal and emerging classes of small-molecule therapeutics form covalent protein adducts. In vivo, both the resulting conjugates and their off-target side-conjugates have the potential to elicit antibodies, with implications for allergy and drug sequestration. Although β-lactam antibiotics are a drug class long associated with these immunological phenomena, the molecular underpinnings of off-target drug-protein conjugation and consequent drug-specific immune responses remain incomplete. Here, using the classical β-lactam penicillin G (PenG), we probe the B and T cell determinants of drug-specific IgG responses to such conjugates in mice. Deep B cell clonotyping reveals a dominant murine clonal antibody class encompassing phylogenetically-related IGHV1, IGHV5 and IGHV10 subgroup gene segments. Protein NMR and x-ray structural analyses reveal that these drive structurally convergent binding modes in adduct-specific antibody clones. Their common primary recognition mechanisms of the penicillin side-chain moiety (phenylacetamide in PenG)-regardless of CDRH3 length-limits cross-reactivity against other β-lactam antibiotics. This immunogenetics-guided discovery of the limited binding solutions available to antibodies against side products of an archetypal covalent inhibitor now suggests future potential strategies for the 'germline-guided reverse engineering' of such drugs away from unwanted immune responses.
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Affiliation(s)
- Lachlan P Deimel
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK.
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY, 10065, USA.
| | - Lucile Moynié
- Rosalind Franklin Institute, Harwell Science and Innovation Campus, Oxford, OX11 0FA, UK
| | - Guoxuan Sun
- Rosalind Franklin Institute, Harwell Science and Innovation Campus, Oxford, OX11 0FA, UK
| | - Viliyana Lewis
- Rosalind Franklin Institute, Harwell Science and Innovation Campus, Oxford, OX11 0FA, UK
| | - Abigail Turner
- Rosalind Franklin Institute, Harwell Science and Innovation Campus, Oxford, OX11 0FA, UK
| | - Charles J Buchanan
- Rosalind Franklin Institute, Harwell Science and Innovation Campus, Oxford, OX11 0FA, UK
- Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building, University of Oxford, Oxford, OX1 3QU, UK
| | - Sean A Burnap
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building, University of Oxford, Oxford, OX1 3QU, UK
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Mikhail Kutuzov
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Carolin M Kobras
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Yana Demyaneko
- Rosalind Franklin Institute, Harwell Science and Innovation Campus, Oxford, OX11 0FA, UK
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK
| | - Shabaz Mohammed
- Rosalind Franklin Institute, Harwell Science and Innovation Campus, Oxford, OX11 0FA, UK
- Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Mathew Stracy
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Weston B Struwe
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building, University of Oxford, Oxford, OX1 3QU, UK
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Andrew J Baldwin
- Rosalind Franklin Institute, Harwell Science and Innovation Campus, Oxford, OX11 0FA, UK
- Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building, University of Oxford, Oxford, OX1 3QU, UK
| | - James Naismith
- Rosalind Franklin Institute, Harwell Science and Innovation Campus, Oxford, OX11 0FA, UK
| | - Benjamin G Davis
- Rosalind Franklin Institute, Harwell Science and Innovation Campus, Oxford, OX11 0FA, UK.
- Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK.
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK.
| | - Quentin J Sattentau
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK.
- The Max Delbrück Centre for Molecular Medicine, Campus Berlin-Buch, 13125, Berlin, Germany.
- Experimental and Clinical Research Center (ECRC), Charité Universitätsmedizin Berlin and Max-Delbrück-Center for Molecular Medicine, Lindenberger Weg 80, 13125, Berlin, Germany.
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3
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Mueller Brown K, Eutsey R, Gazioglu O, Wang D, Vallon A, Rosch JW, Yesilkaya H, Hiller NL. Peptide maturation molecules act as molecular gatekeepers to coordinate cell-cell communication in Streptococcus pneumoniae. Cell Rep 2024; 43:114432. [PMID: 38963762 PMCID: PMC11323143 DOI: 10.1016/j.celrep.2024.114432] [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: 01/12/2024] [Revised: 05/14/2024] [Accepted: 06/19/2024] [Indexed: 07/06/2024] Open
Abstract
The human pathogen Streptococcus pneumoniae (Spn) encodes several cell-cell communication systems, notably multiple members of the Rgg/SHP and the Tpr/Phr families. Until now, members of these diverse communication systems were thought to work independently. Our study reveals that the ABC transporter PptAB and the transmembrane enzyme Eep act as a molecular link between Rgg/SHP and TprA/PhrA systems. We demonstrate that PptAB/Eep activates the Rgg/SHP systems and represses the TprA/PhrA system. Specifically, they regulate the respective precursor peptides (SHP and PhrA) before these leave the cell. This dual mode of action leads to temporal coordination of these systems, producing an overlap between their respective regulons during host cell infection. Thus, we have identified a single molecular mechanism that targets diverse cell-cell communication systems in Spn. Moreover, these molecular components are encoded by many gram-positive bacteria, suggesting that this mechanism may be broadly conserved.
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Affiliation(s)
- Karina Mueller Brown
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Rory Eutsey
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Ozcan Gazioglu
- Department of Respiratory Sciences, University of Leicester, Leicester, UK
| | - Derek Wang
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Amanda Vallon
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Jason W Rosch
- Department of Host-Microbe Interactions, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Hasan Yesilkaya
- Department of Respiratory Sciences, University of Leicester, Leicester, UK
| | - N Luisa Hiller
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA.
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4
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Lyu Y, Yang F, Sundaresh B, Rosconi F, van Opijnen T, Gao J. Covalent Inhibition of a Host-Pathogen Protein-Protein Interaction Reduces the Infectivity of Streptococcus pneumoniae. JACS AU 2024; 4:2484-2491. [PMID: 39055144 PMCID: PMC11267552 DOI: 10.1021/jacsau.4c00195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Revised: 05/29/2024] [Accepted: 05/31/2024] [Indexed: 07/27/2024]
Abstract
The ever-expanding antibiotic resistance urgently calls for novel antibacterial therapeutics, especially those with a new mode of action. We report herein our exploration of protein-protein interaction (PPI) inhibition as a new mechanism to thwart bacterial pathogenesis. Specifically, we describe potent and specific inhibitors of the pneumococcal surface protein PspC, an important virulence factor that facilitates the infection of Streptococcus pneumoniae. Specifically, PspC has been documented to recruit human complement factor H (hFH) to suppress host complement activation and/or promote the bacterial attachment to host tissues. The CCP9 domain of hFH was recombinantly expressed to inhibit the PspC-hFH interaction as demonstrated on live pneumococcal cells. The inhibitor allowed for the first pharmacological intervention of the PspC-hFH interaction. This PPI inhibition reduced pneumococci's attachment to epithelial cells and also resensitized the D39 strain of S. pneumoniae for opsonization. Importantly, we have further devised covalent versions of CCP9, which afforded long-lasting PspC inhibition with low nanomolar potency. Overall, our results showcase the promise of PPI inhibition for combating bacterial infections as well as the power of covalent inhibitors.
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Affiliation(s)
- Yuhan Lyu
- Department
of Chemistry, Merkert Chemistry Center, Boston College, Chestnut
Hill, Massachusetts 02467, United States
| | - Fan Yang
- Department
of Chemistry, Merkert Chemistry Center, Boston College, Chestnut
Hill, Massachusetts 02467, United States
| | - Bharathi Sundaresh
- Department
of Biology, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Federico Rosconi
- Department
of Biology, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Tim van Opijnen
- Broad
Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, Massachusetts 02142, United States
| | - Jianmin Gao
- Department
of Chemistry, Merkert Chemistry Center, Boston College, Chestnut
Hill, Massachusetts 02467, United States
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5
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Zhang C, Liu J, Liu X, Xu Y, Gan Q, Cheng Q, Liu W, Gao X, Wu S. Glutamine enhances pneumococcal growth under methionine semi-starvation by elevating intracellular pH. Front Microbiol 2024; 15:1430038. [PMID: 39044959 PMCID: PMC11263215 DOI: 10.3389/fmicb.2024.1430038] [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: 05/09/2024] [Accepted: 06/28/2024] [Indexed: 07/25/2024] Open
Abstract
Introduction Bacteria frequently encounter nutrient limitation in nature. The ability of living in this nutrient shortage environment is vital for bacteria to preserve their population and important for some pathogenic bacteria to cause infectious diseases. Usually, we study how bacteria survive after nutrient depletion, a total starvation condition when bacteria almost cease growth and try to survive. However, nutrient limitation may not always lead to total starvation. Methods Bacterial adaptation to nutrient shortage was studied by determining bacterial growth curves, intracellular pH, intracellular amino acid contents, gene transcription, protein expression, enzyme activity, and translation and replication activities. Results No exogenous supply of methionine results in growth attenuation of Streptococcus pneumoniae, a human pathogen. In this paper, we refer to this inhibited growth state between ceased growth under total starvation and full-speed growth with full nutrients as semi-starvation. Similar to total starvation, methionine semi-starvation also leads to intracellular acidification. Surprisingly, it is intracellular acidification but not insufficient methionine synthesis that causes growth attenuation under methionine semi-starvation. With excessive glutamine supply in the medium, intracellular methionine level was not changed, while bacterial intracellular pH was elevated to ~ 7.6 (the optimal intracellular pH for pneumococcal growth) by glutamine deamination, and bacterial growth under semi-starvation was restored fully. Our data suggest that intracellular acidification decreases translation level and glutamine supply increases intracellular pH to restore translation level, thus restoring bacterial growth. Discussion This growth with intracellular pH adjustment by glutamine is a novel strategy we found for bacterial adaptation to nutrient shortage, which may provide new drug targets to inhibit growth of pathogenic bacteria under semi-starvation.
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Affiliation(s)
- Chengwang Zhang
- Department of Basic Medical Science, School of Medicine, Lishui University, Lishui, Zhejiang, China
| | - Juncheng Liu
- Department of Basic Medical Science, School of Medicine, Lishui University, Lishui, Zhejiang, China
| | - Xiaohui Liu
- National Protein Science Facility, Tsinghua University, Beijing, China
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Yueyu Xu
- Department of Basic Medical Science, School of Medicine, Lishui University, Lishui, Zhejiang, China
| | - Qingxiu Gan
- Department of Basic Medical Science, School of Medicine, Lishui University, Lishui, Zhejiang, China
| | - Qinqian Cheng
- Department of Basic Medical Science, School of Medicine, Lishui University, Lishui, Zhejiang, China
| | - Weiping Liu
- Department of Basic Medical Science, School of Medicine, Lishui University, Lishui, Zhejiang, China
| | - Xiangmin Gao
- Department of Basic Medical Science, School of Medicine, Lishui University, Lishui, Zhejiang, China
| | - Songquan Wu
- Department of Basic Medical Science, School of Medicine, Lishui University, Lishui, Zhejiang, China
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6
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Rahman MM, Zamakhaeva S, Rush JS, Chaton CT, Kenner CW, Hla YM, Tsui HCT, Uversky VN, Winkler ME, Korotkov KV, Korotkova N. O-glycosylation of intrinsically disordered regions regulates homeostasis of membrane proteins in streptococci. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.05.592596. [PMID: 38746434 PMCID: PMC11092751 DOI: 10.1101/2024.05.05.592596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Proteins harboring intrinsically disordered regions (IDRs) lacking stable secondary or tertiary structures are abundant across the three domains of life. These regions have not been systematically studied in prokaryotes. Our genome-wide analysis identifies extracytoplasmic serine/threonine-rich IDRs in several biologically important membrane proteins in streptococci. We demonstrate that these IDRs are O-glycosylated with glucose by glycosyltransferases GtrB and PgtC2 in Streptococcus pyogenes and Streptococcus pneumoniae, and with N-acetylgalactosamine by a Pgf-dependent mechanism in Streptococcus mutans. Absence of glycosylation leads to a defect in biofilm formation under ethanol-stressed conditions in S. mutans. We link this phenotype to the C-terminal IDR of a post-translocation secretion chaperone PrsA. O-glycosylation of the IDR protects this region from proteolytic degradation. The IDR length attenuates the efficiency of glycosylation and, consequently, the expression level of PrsA. Taken together, our data reveal that O-glycosylation of IDRs functions as a dynamic switch of protein homeostasis in streptococci.
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Affiliation(s)
- Mohammad M. Rahman
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
| | - Svetlana Zamakhaeva
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
| | - Jeffrey S. Rush
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Catherine T. Chaton
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Cameron W. Kenner
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
| | - Yin Mon Hla
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, USA
| | | | - Vladimir N. Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Malcolm E. Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Konstantin V. Korotkov
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Natalia Korotkova
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
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7
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Chan JM, Ramos-Sevillano E, Betts M, Wilson HU, Weight CM, Houhou-Ousalah A, Pollara G, Brown JS, Heyderman RS. Bacterial surface lipoproteins mediate epithelial microinvasion by Streptococcus pneumoniae. Infect Immun 2024; 92:e0044723. [PMID: 38629841 DOI: 10.1128/iai.00447-23] [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: 11/02/2023] [Accepted: 03/27/2024] [Indexed: 05/08/2024] Open
Abstract
Streptococcus pneumoniae, a common colonizer of the upper respiratory tract, invades nasopharyngeal epithelial cells without causing disease in healthy participants of controlled human infection studies. We hypothesized that surface expression of pneumococcal lipoproteins, recognized by the innate immune receptor TLR2, mediates epithelial microinvasion. Mutation of lgt in serotype 4 (TIGR4) and serotype 6B (BHN418) pneumococcal strains abolishes the ability of the mutants to activate TLR2 signaling. Loss of lgt also led to the concomitant decrease in interferon signaling triggered by the bacterium. However, only BHN418 lgt::cm but not TIGR4 lgt::cm was significantly attenuated in epithelial adherence and microinvasion compared to their respective wild-type strains. To test the hypothesis that differential lipoprotein repertoires in TIGR4 and BHN418 lead to the intraspecies variation in epithelial microinvasion, we employed a motif-based genome analysis and identified an additional 525 a.a. lipoprotein (pneumococcal accessory lipoprotein A; palA) encoded by BHN418 that is absent in TIGR4. The gene encoding palA sits within a putative genetic island present in ~10% of global pneumococcal isolates. While palA was enriched in the carriage and otitis media pneumococcal strains, neither mutation nor overexpression of the gene encoding this lipoprotein significantly changed microinvasion patterns. In conclusion, mutation of lgt attenuates epithelial inflammatory responses during pneumococcal-epithelial interactions, with intraspecies variation in the effect on microinvasion. Differential lipoprotein repertoires encoded by the different strains do not explain these differences in microinvasion. Rather, we postulate that post-translational modifications of lipoproteins may account for the differences in microinvasion.IMPORTANCEStreptococcus pneumoniae (pneumococcus) is an important mucosal pathogen, estimated to cause over 500,000 deaths annually. Nasopharyngeal colonization is considered a necessary prerequisite for disease, yet many people are transiently and asymptomatically colonized by pneumococci without becoming unwell. It is therefore important to better understand how the colonization process is controlled at the epithelial surface. Controlled human infection studies revealed the presence of pneumococci within the epithelium of healthy volunteers (microinvasion). In this study, we focused on the regulation of epithelial microinvasion by pneumococcal lipoproteins. We found that pneumococcal lipoproteins induce epithelial inflammation but that differing lipoprotein repertoires do not significantly impact the magnitude of microinvasion. Targeting mucosal innate immunity and epithelial microinvasion alongside the induction of an adaptive immune response may be effective in preventing pneumococcal colonization and disease.
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Affiliation(s)
- Jia Mun Chan
- Research Department of Infection, Division of Infection and Immunity, University College London, London, United Kingdom
| | - Elisa Ramos-Sevillano
- UCL Respiratory, Division of Medicine, University College London, London, United Kingdom
| | - Modupeh Betts
- Research Department of Infection, Division of Infection and Immunity, University College London, London, United Kingdom
| | - Holly U Wilson
- Research Department of Infection, Division of Infection and Immunity, University College London, London, United Kingdom
| | - Caroline M Weight
- Research Department of Infection, Division of Infection and Immunity, University College London, London, United Kingdom
| | - Ambrine Houhou-Ousalah
- Research Department of Infection, Division of Infection and Immunity, University College London, London, United Kingdom
| | - Gabriele Pollara
- Research Department of Infection, Division of Infection and Immunity, University College London, London, United Kingdom
| | - Jeremy S Brown
- UCL Respiratory, Division of Medicine, University College London, London, United Kingdom
| | - Robert S Heyderman
- Research Department of Infection, Division of Infection and Immunity, University College London, London, United Kingdom
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8
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Shirley JD, Nauta KM, Gillingham JR, Diwakar S, Carlson EE. kinact / KI Value Determination for Penicillin-Binding Proteins in Live Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.05.592586. [PMID: 38746240 PMCID: PMC11092749 DOI: 10.1101/2024.05.05.592586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Penicillin-binding proteins (PBPs) are an essential family of bacterial enzymes that are inhibited by the β-lactam class of antibiotics. PBP inhibition disrupts cell wall biosynthesis, which results in deficient growth and proliferation, and ultimately leads to lysis. IC 50 values are often employed as descriptors of enzyme inhibition and inhibitor selectivity but can be misleading in the study of time-dependent, irreversible inhibitors. Due to this disconnect, the second order rate constant k inact / K I is a more appropriate metric of covalent inhibitor potency. Despite being the gold standard measurement of potency, k inact / K I values are typically obtained from in vitro assays, which limits assay throughput if investigating an enzyme family with multiple homologs (such as the PBPs). Therefore, we developed a whole-cell k inact / K I assay to define inhibitor potency for the PBPs in Streptococcus pneumoniae using the fluorescent activity-based probe Bocillin-FL. Our results align with in vitro k inact / K I data and show a comparable relationship to previously established IC 50 values. These results support the validity of our in vivo k inact / K I method as a means of obtaining a full picture of β-lactam potency for a suite of PBPs. Abstract Figure
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9
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Jiang W, Lin T, Pan J, Rivera CE, Tincher C, Wang Y, Zhang Y, Gao X, Wang Y, Tsui HCT, Winkler ME, Lynch M, Long H. Spontaneous mutations and mutational responses to penicillin treatment in the bacterial pathogen Streptococcus pneumoniae D39. MARINE LIFE SCIENCE & TECHNOLOGY 2024; 6:198-211. [PMID: 38827133 PMCID: PMC11136922 DOI: 10.1007/s42995-024-00220-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 03/04/2024] [Indexed: 06/04/2024]
Abstract
Bacteria with functional DNA repair systems are expected to have low mutation rates due to strong natural selection for genomic stability. However, our study of the wild-type Streptococcus pneumoniae D39, a pathogen responsible for many common diseases, revealed a high spontaneous mutation rate of 0.02 per genome per cell division in mutation-accumulation (MA) lines. This rate is orders of magnitude higher than that of other non-mutator bacteria and is characterized by a high mutation bias in the A/T direction. The high mutation rate may have resulted from a reduction in the overall efficiency of selection, conferred by the tiny effective population size in nature. In line with this, S. pneumoniae D39 also exhibited the lowest DNA mismatch-repair (MMR) efficiency among bacteria. Treatment with the antibiotic penicillin did not elevate the mutation rate, as penicillin did not induce DNA damage and S. pneumoniae lacks a stress response pathway. Our findings suggested that the MA results are applicable to within-host scenarios and provide insights into pathogen evolution. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-024-00220-6.
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Affiliation(s)
- Wanyue Jiang
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Laoshan Laboratory, Qingdao, 266237 China
| | - Tongtong Lin
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
| | - Jiao Pan
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
| | - Caitlyn E. Rivera
- Department of Biology, Indiana University, Bloomington, IN 47405 USA
| | - Clayton Tincher
- Department of Biology, Indiana University, Bloomington, IN 47405 USA
| | - Yaohai Wang
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
| | - Yu Zhang
- School of Mathematics Science, Ocean University of China, Qingdao, 266000 China
| | - Xiang Gao
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, School of Life Science, Shandong University, Qingdao, 266237 China
| | - Yan Wang
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
| | - Ho-Ching T. Tsui
- Department of Biology, Indiana University, Bloomington, IN 47405 USA
| | | | - Michael Lynch
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85281 USA
| | - Hongan Long
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Laoshan Laboratory, Qingdao, 266237 China
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10
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Jaroch M, Sun G, Tsui HCT, Reed C, Sun J, Jörg M, Winkler ME, Rice KC, Dziergowska A, Stich TA, Dedon PC, Dos Santos PC, de Crécy-Lagard V. Alternate routes to mnm 5s 2U synthesis in Gram-positive bacteria. J Bacteriol 2024; 206:e0045223. [PMID: 38551342 PMCID: PMC11025329 DOI: 10.1128/jb.00452-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 03/09/2024] [Indexed: 04/09/2024] Open
Abstract
The wobble bases of tRNAs that decode split codons are often heavily modified. In bacteria, tRNAGlu, Gln, Asp contains a variety of xnm5s2U derivatives. The synthesis pathway for these modifications is complex and fully elucidated only in a handful of organisms, including the Gram-negative Escherichia coli K12 model. Despite the ubiquitous presence of mnm5s2U modification, genomic analysis shows the absence of mnmC orthologous genes, suggesting the occurrence of alternate biosynthetic schemes for the conversion of cmnm5s2U to mnm5s2U. Using a combination of comparative genomics and genetic studies, a member of the YtqA subgroup of the radical Sam superfamily was found to be involved in the synthesis of mnm5s2U in both Bacillus subtilis and Streptococcus mutans. This protein, renamed MnmL, is encoded in an operon with the recently discovered MnmM methylase involved in the methylation of the pathway intermediate nm5s2U into mnm5s2U in B. subtilis. Analysis of tRNA modifications of both S. mutans and Streptococcus pneumoniae shows that growth conditions and genetic backgrounds influence the ratios of pathway intermediates owing to regulatory loops that are not yet understood. The MnmLM pathway is widespread along the bacterial tree, with some phyla, such as Bacilli, relying exclusively on these two enzymes. Although mechanistic details of these newly discovered components are not fully resolved, the occurrence of fusion proteins, alternate arrangements of biosynthetic components, and loss of biosynthetic branches provide examples of biosynthetic diversity to retain a conserved tRNA modification in Nature.IMPORTANCEThe xnm5s2U modifications found in several tRNAs at the wobble base position are widespread in bacteria where they have an important role in decoding efficiency and accuracy. This work identifies a novel enzyme (MnmL) that is a member of a subgroup of the very versatile radical SAM superfamily and is involved in the synthesis of mnm5s2U in several Gram-positive bacteria, including human pathogens. This is another novel example of a non-orthologous displacement in the field of tRNA modification synthesis, showing how different solutions evolve to retain U34 tRNA modifications.
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Affiliation(s)
- Marshall Jaroch
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Guangxin Sun
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Singapore-MIT Alliance for Research and Technology, CREATE Tower, Singapore
| | | | - Colbie Reed
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Jingjing Sun
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Singapore-MIT Alliance for Research and Technology, CREATE Tower, Singapore
| | - Marko Jörg
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Malcolm E. Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Kelly C. Rice
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | | | - Troy A. Stich
- Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina, USA
| | - Peter C. Dedon
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Singapore-MIT Alliance for Research and Technology, CREATE Tower, Singapore
| | | | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
- University of Florida Genetics Institute, Gainesville, Florida, USA
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11
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Mitchell SL, Kearns DB, Carlson EE. Penicillin-binding protein redundancy in Bacillus subtilis enables growth during alkaline shock. Appl Environ Microbiol 2024; 90:e0054823. [PMID: 38126750 PMCID: PMC10807460 DOI: 10.1128/aem.00548-23] [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: 04/03/2023] [Accepted: 11/13/2023] [Indexed: 12/23/2023] Open
Abstract
Penicillin-binding proteins (PBPs) play critical roles in cell wall construction, cell shape maintenance, and bacterial replication. Bacteria maintain a diversity of PBPs, indicating that despite their apparent functional redundancy, there is differentiation across the PBP family. Apparently-redundant proteins can be important for enabling an organism to cope with environmental stressors. In this study, we evaluated the consequence of environmental pH on PBP enzymatic activity in Bacillus subtilis. Our data show that a subset of PBPs in B. subtilis change activity levels during alkaline shock and that one PBP isoform is rapidly modified to generate a smaller protein (i.e., PBP1a to PBP1b). Our results indicate that a subset of the PBPs are favored for growth under alkaline conditions, while others are readily dispensable. Indeed, we found that this phenomenon could also be observed in Streptococcus pneumoniae, implying that it may be generalizable across additional bacterial species and further emphasizing the evolutionary benefit of maintaining many, seemingly-redundant periplasmic enzymes.IMPORTANCEMicrobes adapt to ever-changing environments and thrive over a vast range of conditions. While bacterial genomes are relatively small, significant portions encode for "redundant" functions. Apparent redundancy is especially pervasive in bacterial proteins that reside outside of the inner membrane. While conditions within the cytoplasm are carefully controlled, those of the periplasmic space are largely determined by the cell's exterior environment. As a result, proteins within this environmentally exposed region must be capable of functioning under a vast array of conditions, and/or there must be several similar proteins that have evolved to function under a variety of conditions. This study examines the activity of a class of enzymes that is essential in cell wall construction to determine if individual proteins might be adapted for activity under particular growth conditions. Our results indicate that a subset of these proteins are preferred for growth under alkaline conditions, while others are readily dispensable.
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Affiliation(s)
| | - Daniel B. Kearns
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - Erin E. Carlson
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
- Departments of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, United States
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, United States
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12
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Scasny A, Alibayov B, Khan F, Rao SJ, Murin L, Jop Vidal AG, Smith P, Li W, Edwards K, Warncke K, Vidal JE. Oxidation of hemoproteins by Streptococcus pneumoniae collapses the cell cytoskeleton and disrupts mitochondrial respiration leading to the cytotoxicity of human lung cells. Microbiol Spectr 2024; 12:e0291223. [PMID: 38084982 PMCID: PMC10783075 DOI: 10.1128/spectrum.02912-23] [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: 07/24/2023] [Accepted: 11/06/2023] [Indexed: 12/21/2023] Open
Abstract
IMPORTANCE Streptococcus pneumoniae (Spn) colonizes the lungs, killing millions every year. During its metabolism, Spn produces abundant amounts of hydrogen peroxide. When produced in the lung parenchyma, Spn-hydrogen peroxide (H2O2) causes the death of lung cells, and details of the mechanism are studied here. We found that Spn-H2O2 targets intracellular proteins, resulting in the contraction of the cell cytoskeleton and disruption of mitochondrial function, ultimately contributing to cell death. Intracellular proteins targeted by Spn-H2O2 included cytochrome c and, surprisingly, a protein of the cell cytoskeleton, beta-tubulin. To study the details of oxidative reactions, we used, as a surrogate model, the oxidation of another hemoprotein, hemoglobin. Using the surrogate model, we specifically identified a highly reactive radical whose creation was catalyzed by Spn-H2O2. In sum, we demonstrated that the oxidation of intracellular targets by Spn-H2O2 plays an important role in the cytotoxicity caused by Spn, thus providing new targets for interventions.
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Affiliation(s)
- Anna Scasny
- Department of Cell and Molecular Biology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
- Center for Immunology and Microbial Research, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Babek Alibayov
- Department of Cell and Molecular Biology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
- Center for Immunology and Microbial Research, 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
- Center for Immunology and Microbial Research, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Shambavi J. Rao
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State School of Medicine, The Ohio State Wexner Medical Center, Columbus, Ohio, USA
| | - Landon Murin
- Department of Cell and Molecular Biology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
- Center for Immunology and Microbial Research, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Ana G. Jop Vidal
- Department of Cell and Molecular Biology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
- Center for Immunology and Microbial Research, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Perriann Smith
- Mississippi INBRE Research Scholar, University of Southern Mississippi, Jackson, Mississippi, USA
| | - Wei Li
- Department of Physics, Emory University, Atlanta, Georgia, USA
| | - Kristin Edwards
- Department of Cell and Molecular Biology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Kurt Warncke
- Department of Physics, Emory University, Atlanta, Georgia, USA
| | - Jorge E. Vidal
- Department of Cell and Molecular Biology, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
- Center for Immunology and Microbial Research, School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
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13
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Womack E, Alibayov B, Vidal JE, Eichenbaum Z. Endogenously produced H 2O 2 is intimately involved in iron metabolism in Streptococcus pneumoniae. Microbiol Spectr 2024; 12:e0329723. [PMID: 38038454 PMCID: PMC10783112 DOI: 10.1128/spectrum.03297-23] [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: 09/08/2023] [Accepted: 11/02/2023] [Indexed: 12/02/2023] Open
Abstract
IMPORTANCE Heme degradation provides pathogens with growth essential iron, leveraging on the host heme reservoir. Bacteria typically import and degrade heme enzymatically, and here, we demonstrated a significant deviation from this dogma. We found that Streptococcus pneumoniae liberates iron from met-hemoglobin extracellularly, in a hydrogen peroxide (H2O2)- and cell-dependent manner; this activity serves as a major iron acquisition mechanism for S. pneumoniae. Inhabiting oxygen-rich environments is a major part of pneumococcal biology, and hence, H2O2-mediated heme degradation likely supplies iron during infection. Moreover, H2O2 reaction with ferrous hemoglobin but not with met-hemoglobin is known to result in heme breakdown. Therefore, the ability of pneumococci to degrade heme from met-hemoglobin is a new paradigm. Lastly, this study will inform other research as it demonstrates that extracellular degradation must be considered in the interpretations of experiments in which H2O2-producing bacteria are given heme or hemoproteins as an iron source.
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Affiliation(s)
- Edroyal Womack
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
| | - Babek Alibayov
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, Mississippi, USA
- School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Jorge E. Vidal
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, Mississippi, USA
- School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Zehava Eichenbaum
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
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14
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Wu X, Alibayov B, Xiang X, Lattar SM, Sakai F, Medders AA, Antezana B, Keller L, Vidal AGJ, Tzeng YL, Robinson DA, Stephens D, Yu Y, Vidal JE. Ultrastructural, metabolic and genetic determinants of the acquisition of macrolide resistance by Streptococcus pneumoniae. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.27.573471. [PMID: 38234816 PMCID: PMC10793443 DOI: 10.1101/2023.12.27.573471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Aim Streptococcus pneumoniae (Spn) acquires genes for macrolide resistance, MEGA or ermB, in the human host. These genes are carried either in the chromosome, or on integrative conjugative elements (ICEs). Here, we investigated molecular determinants of the acquisition of macrolide resistance. Methods and Results Whole genome analysis was conducted for 128 macrolide-resistant pneumococcal isolates to identify the presence of MEGA (44.5%, 57/128) or ermB (100%), and recombination events in Tn916-related elements or in the locus comCDE encoding competence genes. Confocal and electron microscopy studies demonstrated that, during the acquisition of macrolide resistance, pneumococcal strains formed clusters of varying size, with the largest aggregates having a median size of ~1600 μm2. Remarkably, these pneumococcal aggregates comprise both encapsulated and nonencapsulated pneumococci, exhibited physical interaction, and spanned extracellular and intracellular compartments. We assessed the recombination frequency (rF) for the acquisition of macrolide resistance by a recipient D39 strain, from pneumococcal strains carrying MEGA (~5.4 kb) in the chromone, or in large ICEs (>23 kb). Notably, the rF for the acquisition of MEGA, whether in the chromosome or carried on an ICE was similar. However, the rF adjusted to the acquisition of the full-length ICE (~52 kb), compared to that of the capsule locus (~23 kb) that is acquired by transformation, was three orders of magnitude higher. Finally, metabolomics studies revealed a link between the acquisition of ICE and the metabolic pathways involving nicotinic acid and sucrose. Conclusions Extracellular and intracellular pneumococcal clusters facilitate the acquisition of full-length ICE at a rF higher than that of typical transformation events, involving distinct metabolic changes that present potential targets for interventions.
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Affiliation(s)
- Xueqing Wu
- Department of Infectious Diseases, Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310052, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou 310052, China
| | - Babek Alibayov
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson MS 39056, United States
| | - Xi Xiang
- Department of Clinical Laboratory, Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua 321000, China
| | - Santiago M. Lattar
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta GA 30322, United States
| | - Fuminori Sakai
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta GA 30322, United States
| | - Austin A. Medders
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson MS 39056, United States
| | - Brenda Antezana
- Department of Medicine, School of Medicine, Emory University, Atlanta GA 30322, United States
| | - Lance Keller
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson MS 39056, United States
| | - Ana G. J. Vidal
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson MS 39056, United States
| | - Yih-Ling Tzeng
- Department of Medicine, School of Medicine, Emory University, Atlanta GA 30322, United States
| | - D. Ashley Robinson
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson MS 39056, United States
| | - David Stephens
- Department of Medicine, School of Medicine, Emory University, Atlanta GA 30322, United States
| | - Yunsong Yu
- Department of Infectious Diseases, Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310052, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou 310052, China
| | - Jorge E. Vidal
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson MS 39056, United States
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15
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Jaroch M, Sun G, Tsui HCT, Reed C, Sun J, Jörg M, Winkler ME, Rice KC, Stich TA, Dedon PC, Dos Santos PC, de Crécy-Lagard V. Alternate routes to mnm 5 s 2 U synthesis in Gram-positive bacteria. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.21.572861. [PMID: 38187551 PMCID: PMC10769405 DOI: 10.1101/2023.12.21.572861] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
The wobble bases of tRNAs that decode split codons are often heavily modified. In Bacteria tRNA Glu, Gln, Asp contain a variety of xnm 5 s 2 U derivatives. The synthesis pathway for these modifications is complex and fully elucidated only in a handful of organisms, including the Gram-negative Escherichia coli K12 model. Despite the ubiquitous presence of mnm 5 s 2 U modification, genomic analysis shows the absence of mnmC orthologous genes, suggesting the occurrence of alternate biosynthetic schemes for the installation of this modification. Using a combination of comparative genomics and genetic studies, a member of the YtqA subgroup of the Radical Sam superfamily was found to be involved in the synthesis of mnm 5 s 2 U in both Bacillus subtilis and Streptococcus mutans . This protein, renamed MnmL, is encoded in an operon with the recently discovered MnmM methylase involved in the methylation of the pathway intermediate nm 5 s 2 U into mnm 5 s 2 U in B. subtilis . Analysis of tRNA modifications of both S. mutans and Streptococcus pneumoniae shows that growth conditions and genetic backgrounds influence the ratios of pathways intermediates in regulatory loops that are not yet understood. The MnmLM pathway is widespread along the bacterial tree, with some phyla, such as Bacilli, relying exclusively on these two enzymes. The occurrence of fusion proteins, alternate arrangements of biosynthetic components, and loss of biosynthetic branches provide examples of biosynthetic diversity to retain a conserved tRNA modification in nature. Importance The xnm 5 s 2 U modifications found in several tRNAs at the wobble base position are widespread in Bacteria where they have an important role in decoding efficiency and accuracy. This work identifies a novel enzyme (MnmL) that is a member of a subgroup of the very versatile Radical SAM superfamily and is involved in the synthesis of mnm 5 s 2 U in several Gram-positive bacteria, including human pathogens. This is another novel example of a non-orthologous displacement in the field of tRNA modification synthesis, showing how different solutions evolve to retain U34 tRNA modifications.
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16
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Lane JR, Tata M, Yasmin R, Im H, Briles DE, Orihuela CJ. PspA-mediated aggregation protects Streptococcus pneumoniae against desiccation on fomites. mBio 2023; 14:e0263423. [PMID: 37982608 PMCID: PMC10746202 DOI: 10.1128/mbio.02634-23] [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: 09/27/2023] [Accepted: 10/10/2023] [Indexed: 11/21/2023] Open
Abstract
IMPORTANCE Spn is a dangerous human pathogen capable of causing pneumonia and invasive disease. The virulence factor PspA has been studied for nearly four decades with well-established roles in pneumococcal evasion of C-reactive protein and neutralization of lactoferricin. Herein, we show that mammalian (m)GAPDH in mucosal secretions promotes aggregation of pneumococci in a PspA-dependent fashion, whereas lactoferrin counters this effect. PspA-mediated GAPDH-dependent bacterial aggregation protected Spn in nasal lavage elutes and grown in vitro from desiccation on fomites. Furthermore, surviving pneumococci within these aggregates retained their ability to colonize naïve hosts after desiccation. We report that Spn binds to and forms protein complexes on its surface composed of PspA, mGAPDH, and lactoferrin. Changes in the levels of these proteins therefore most likely have critical implications on Spn colonization, survival on fomites, and transmission.
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Affiliation(s)
- Jessica R. Lane
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Muralidhar Tata
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Rahena Yasmin
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Hansol Im
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - David E. Briles
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Carlos J. Orihuela
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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17
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Midonet C, Bisset S, Shlosman I, Cava F, Rudner DZ, Bernhardt TG. MacP bypass variants of Streptococcus pneumoniae PBP2a suggest a conserved mechanism for the activation of bifunctional cell wall synthases. mBio 2023; 14:e0239023. [PMID: 37847021 PMCID: PMC10746261 DOI: 10.1128/mbio.02390-23] [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: 09/01/2023] [Accepted: 09/06/2023] [Indexed: 10/18/2023] Open
Abstract
IMPORTANCE Class A penicillin-binding proteins (aPBPs) play critical roles in bacterial cell wall biogenesis. As the targets of penicillin, they are among the most important drug targets in history. Although the biochemical activities of these enzymes have been well studied, little is known about how they are regulated in cells to control when and where peptidoglycan is made. In this report, we isolate variants of the Streptococcus pneumoniae enzyme PBP2a that function in cells without MacP, a partner normally required for its activity. The amino acid substitutions activate the cell wall synthase activity of PBP2a, and their location in a model structure suggests an activation mechanism for this enzyme that is shared with aPBPs from distantly related organisms with distinct activators.
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Affiliation(s)
- Caroline Midonet
- Department of Microbiology, Harvard Medical School, Blavatnik Institute, Boston, Massachusetts, USA
| | - Sean Bisset
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Irina Shlosman
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, Massachusetts, USA
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Center for Microbial Research (UCMR), Umea, Sweden
- Department of Molecular Biology, Science for Life Laboratory (SciLifeLab), Umeå University, Umeå, Sweden
| | - David Z. Rudner
- Department of Microbiology, Harvard Medical School, Blavatnik Institute, Boston, Massachusetts, USA
| | - Thomas G. Bernhardt
- Department of Microbiology, Harvard Medical School, Blavatnik Institute, Boston, Massachusetts, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
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18
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Berna AZ, Merriman JA, Mellett L, Parchment DK, Caparon MG, Odom John AR. Volatile profiling distinguishes Streptococcus pyogenes from other respiratory streptococcal species. mSphere 2023; 8:e0019423. [PMID: 37791788 PMCID: PMC10597408 DOI: 10.1128/msphere.00194-23] [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: 04/12/2023] [Accepted: 08/13/2023] [Indexed: 10/05/2023] Open
Abstract
Sore throat is one of the most common complaints encountered in the ambulatory clinical setting. Rapid, culture-independent diagnostic techniques that do not rely on pharyngeal swabs would be highly valuable as a point-of-care strategy to guide outpatient antibiotic treatment. Despite the promise of this approach, efforts to detect volatiles during oropharyngeal infection have yet been limited. In our research study, we sought to evaluate for specific bacterial volatile organic compounds (VOC) biomarkers in isolated cultures in vitro, in order to establish proof-of-concept prior to initial clinical studies of breath biomarkers. A particular challenge for the diagnosis of pharyngitis due to Streptococcus pyogenes is the likelihood that many metabolites may be shared by S. pyogenes and other related oropharyngeal colonizing bacterial species. Therefore, we evaluated whether sufficient metabolic differences are present, which distinguish the volatile metabolome of Group A streptococci from other streptococcal species that also colonize the respiratory mucosa, such as Streptococcus pneumoniae and Streptococcus intermedius. In this work, we identified 27 discriminatory VOCs (q-values < 0.05), composed of aldehydes, alcohols, nitrogen-containing compounds, hydrocarbons, ketones, aromatic compounds, esters, ethers, and carboxylic acid. From this group of volatiles, we identify candidate biomarkers that distinguish S. pyogenes from other species and establish highly produced VOCs that indicate the presence of S. pyogenes in vitro, supporting future breath-based diagnostic testing for streptococcal pharyngitis. IMPORTANCE Acute pharyngitis accounts for approximately 15 million ambulatory care visits in the United States. The most common and important bacterial cause of pharyngitis is Streptococcus pyogenesis, accounting for 15%-30% of pediatric pharyngitis. Distinguishing between bacterial and viral pharyngitis is key to management in US practice. The culture of a specimen obtained by a throat swab is the standard laboratory procedure for the microbiologic confirmation of pharyngitis; however, this method is time-consuming, which delays appropriate treatment. If left untreated, S. pyogenes pharyngitis may lead to local and distant complications. In this study, we characterized the volatile metabolomes of S. pyogenes and other related oropharyngeal colonizing bacterial species. We identify candidate biomarkers that distinguish S. pyogenes from other species and provide evidence to support future breath-based diagnostic testing for streptococcal pharyngitis.
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Affiliation(s)
- Amalia Z. Berna
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Joseph A. Merriman
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
- Microbiome Therapies Initiative, Stanford University, Palo Alto, California, USA
| | - Leah Mellett
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Danealle K. Parchment
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
| | - Michael G. Caparon
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Audrey R. Odom John
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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19
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Kobras CM, Monteith W, Somerville S, Delaney JM, Khan I, Brimble C, Corrigan RM, Sheppard SK, Fenton AK. Loss of Pde1 function acts as an evolutionary gateway to penicillin resistance in Streptococcus pneumoniae. Proc Natl Acad Sci U S A 2023; 120:e2308029120. [PMID: 37796984 PMCID: PMC10576035 DOI: 10.1073/pnas.2308029120] [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: 05/14/2023] [Accepted: 09/05/2023] [Indexed: 10/07/2023] Open
Abstract
Streptococcus pneumoniae is a major human pathogen and rising resistance to β-lactam antibiotics, such as penicillin, is a significant threat to global public health. Mutations occurring in the penicillin-binding proteins (PBPs) can confer high-level penicillin resistance but other poorly understood genetic factors are also important. Here, we combined strictly controlled laboratory experiments and population analyses to identify a new penicillin resistance pathway that is independent of PBP modification. Initial laboratory selection experiments identified high-frequency pde1 mutations conferring S. pneumoniae penicillin resistance. The importance of variation at the pde1 locus was confirmed in natural and clinical populations in an analysis of >7,200 S. pneumoniae genomes. The pde1 mutations identified by these approaches reduce the hydrolytic activity of the Pde1 enzyme in bacterial cells and thereby elevate levels of cyclic-di-adenosine monophosphate and penicillin resistance. Our results reveal rapid de novo loss of function mutations in pde1 as an evolutionary gateway conferring low-level penicillin resistance. This relatively simple genomic change allows cells to persist in populations on an adaptive evolutionary pathway to acquire further genetic changes and high-level penicillin resistance.
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Affiliation(s)
- Carolin M. Kobras
- School for Biosciences, Florey Institute for Host-Pathogen Interactions, University of Sheffield, SheffieldS10 2TN, United Kingdom
| | - William Monteith
- Department of Biology, Ineos Oxford Institute for Antimicrobial Research, University of Oxford, OxfordOX1 3SZ, United Kingdom
| | - Sophie Somerville
- School for Biosciences, Florey Institute for Host-Pathogen Interactions, University of Sheffield, SheffieldS10 2TN, United Kingdom
| | - James M. Delaney
- School for Biosciences, Florey Institute for Host-Pathogen Interactions, University of Sheffield, SheffieldS10 2TN, United Kingdom
| | - Imran Khan
- School for Biosciences, Florey Institute for Host-Pathogen Interactions, University of Sheffield, SheffieldS10 2TN, United Kingdom
| | - Camilla Brimble
- School for Biosciences, Florey Institute for Host-Pathogen Interactions, University of Sheffield, SheffieldS10 2TN, United Kingdom
| | - Rebecca M. Corrigan
- School for Biosciences, Florey Institute for Host-Pathogen Interactions, University of Sheffield, SheffieldS10 2TN, United Kingdom
| | - Samuel K. Sheppard
- Department of Biology, Ineos Oxford Institute for Antimicrobial Research, University of Oxford, OxfordOX1 3SZ, United Kingdom
| | - Andrew K. Fenton
- School for Biosciences, Florey Institute for Host-Pathogen Interactions, University of Sheffield, SheffieldS10 2TN, United Kingdom
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20
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Lane JR, Tata M, Yasmin R, Im H, Briles DE, Orihuela CJ. PspA-mediated aggregation protects Streptococcus pneumoniae against desiccation on fomites. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.27.559802. [PMID: 37808718 PMCID: PMC10557681 DOI: 10.1101/2023.09.27.559802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Streptococcus pneumoniae (Spn) resides in the nasopharynx where it can disseminate to cause disease. One key Spn virulence factor is pneumococcal surface protein A (PspA), which promotes survival by blocking the antimicrobial peptide lactoferricin. PspA has also been shown to mediate attachment to dying epithelial cells in the lower airway due to its binding of cell surface-bound mammalian (m)GAPDH. Importantly, the role of PspA during colonization is not well understood. Wildtype Spn was present in nasal lavage elutes collected from asymptomatically colonized mice at levels ~10-fold higher that its isogenic PspA-deficient mutant (ΔpspA). Wildtype Spn also formed aggregates in mucosal secretions composed of sloughed epithelial cells and hundreds of pneumococci, whereas ΔpspA did not. Spn within the center of these aggregates better survived prolonged desiccation on fomites than individual pneumococci and were capable of infecting naïve mice, indicating PspA-mediated aggregation conferred a survival/transmission advantage. Incubation of Spn in saline containing mGAPDH also enhanced tolerance to desiccation, but only for wildtype Spn. mGAPDH was sufficient to cause low-level aggregation of wildtype Spn but not ΔpspA. In strain WU2, the subdomain of PspA responsible for binding GAPDH (aa230-281) is ensconced within the lactoferrin (LF)-binding domain (aa167-288). We observed that LF inhibited GAPDH-mediated aggregation and desiccation tolerance. Using surface plasmon resonance, we determined that Spn forms multimeric complexes of PspA-GAPDH-LF on its surface and that LF dislodges GAPDH. Our findings have important implications regarding pneumococcal colonization/transmission processes and ongoing PspA-focused immunization efforts for this deadly pathogen.
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Affiliation(s)
- Jessica R. Lane
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, 35209, United States
| | - Muralidhar Tata
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, 35209, United States
| | - Rahena Yasmin
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, 35209, United States
| | - Hansol Im
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, 35209, United States
| | - David E. Briles
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, 35209, United States
| | - Carlos J. Orihuela
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, 35209, United States
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21
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Barnes V L, Heithoff DM, Mahan SP, House JK, Mahan MJ. Antimicrobial susceptibility testing to evaluate minimum inhibitory concentration values of clinically relevant antibiotics. STAR Protoc 2023; 4:102512. [PMID: 37566547 PMCID: PMC10448204 DOI: 10.1016/j.xpro.2023.102512] [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: 06/13/2023] [Revised: 07/03/2023] [Accepted: 07/25/2023] [Indexed: 08/13/2023] Open
Abstract
Antimicrobial susceptibility testing is used to determine the minimum inhibitory concentration (MIC), the standard measurement of antibiotic activity. Here, we present a protocol for evaluating MIC values of clinically relevant antibiotics against bacterial isolates cultured in standard bacteriologic medium and in mammalian cell culture medium. We describe steps for pathogen identification, culturing bacteria, preparing MIC plates, MIC assay incubation, and determining MIC. This protocol can potentially optimize the use of existing antibiotics while enhancing efforts to discover new ones. For complete details on the use and execution of this protocol, please refer to Heithoff et al.1.
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Affiliation(s)
- Lucien Barnes V
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106, USA.
| | - Douglas M Heithoff
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | - Scott P Mahan
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106, USA; Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, CA 95616, USA
| | - John K House
- Faculty of Science, School of Veterinary Science, The University of Sydney, Camden, NSW 2570, Australia
| | - Michael J Mahan
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106, USA.
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22
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Vilhena C, Du S, Battista M, Westermann M, Kohler T, Hammerschmidt S, Zipfel PF. The choline-binding proteins PspA, PspC, and LytA of Streptococcus pneumoniae and their interaction with human endothelial and red blood cells. Infect Immun 2023; 91:e0015423. [PMID: 37551971 PMCID: PMC10501214 DOI: 10.1128/iai.00154-23] [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: 04/26/2023] [Accepted: 06/23/2023] [Indexed: 08/09/2023] Open
Abstract
Streptococcus pneumoniae is a Gram-positive opportunistic pathogen that can colonize the upper respiratory tract. It is a leading cause of a wide range of infectious diseases, including community-acquired pneumonia and meningitis. Pneumococcal infections cause 1-2 million deaths per year, most of which occur in developing countries. Here, we focused on three choline-binding proteins (CBPs), i.e., PspC, PspA, and LytA. These pneumococcal proteins have different surface-exposed regions but share related choline-binding anchors. These surface-exposed pneumococcal proteins are in direct contact with host cells and have diverse functions. We explored the role of the three CBPs on adhesion and pathogenicity in a human host by performing relevant imaging and functional analyses, such as electron microscopy, confocal laser scanning microscopy, and functional quantitative assays, targeting biofilm formation and the hemolytic capacity of S. pneumoniae. In vitro biofilm formation assays and electron microscopy experiments were used to examine the ability of knockout mutant strains lacking the lytA, pspC, or pspA genes to adhere to surfaces. We found that LytA plays an important role in robust synthesis of the biofilm matrix. PspA and PspC appeared crucial for the hemolytic effects of S. pneumoniae on human red blood cells. Furthermore, all knockout mutants caused less damage to endothelial cells than wild-type bacteria, highlighting the significance of each CPB for the overall pathogenicity of S. pneumoniae. Hence, in addition to their structural function within the cell wall of S. pneumoniae, each of these three surface-exposed CBPs controls or mediates multiple steps during bacterial pathogenesis.
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Affiliation(s)
- Cláudia Vilhena
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Shanshan Du
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Miriana Battista
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Martin Westermann
- Centre for Electron Microscopy, Jena University Hospital, Friedrich-Schiller-University of Jena, Jena, Germany
| | - Thomas Kohler
- Department of Molecular Genetics and Infection Biology, Center for Functional Genomics of Microbes, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, Greifswald, Germany
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, Center for Functional Genomics of Microbes, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, Greifswald, Germany
| | - Peter F. Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
- Institute of Microbiology, Friedrich-Schiller-University, Jena, Germany
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23
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Su T, Chua WZ, Liu Y, Fan J, Tan SY, Yang DW, Sham LT. Rewiring the pneumococcal capsule pathway for investigating glycosyltransferase specificity and genetic glycoengineering. SCIENCE ADVANCES 2023; 9:eadi8157. [PMID: 37672581 PMCID: PMC10482335 DOI: 10.1126/sciadv.adi8157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 08/03/2023] [Indexed: 09/08/2023]
Abstract
Virtually all living cells are covered with glycans. Their structures are primarily controlled by the specificities of glycosyltransferases (GTs). GTs typically adopt one of the three folds, namely, GT-A, GT-B, and GT-C. However, what defines their specificities remain poorly understood. Here, we developed a genetic glycoengineering platform by reprogramming the capsular polysaccharide pathways in Streptococcus pneumoniae to interrogate GT specificity and manipulate glycan structures. Our findings suggest that the central cleft of GT-B enzymes is important for determining acceptor specificity. The constraint of the glycoengineering platform was partially alleviated when the specificity of the precursor transporter was reduced, indicating that the transporter contributes to the overall fidelity of glycan synthesis. We also modified the pneumococcal capsule to produce several medically important mammalian glycans, as well as demonstrated the importance of regiochemistry in a glycosidic linkage on binding lung epithelial cells. Our work provided mechanistic insights into GT specificity and an approach for investigating glycan functions.
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Affiliation(s)
- Tong Su
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Wan-Zhen Chua
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Yao Liu
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Jingsong Fan
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117545, Singapore
| | - Si-Yin Tan
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Dai-wen Yang
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117545, Singapore
| | - Lok-To Sham
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
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24
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Li L, Guo T, Yuan Y, Xiao J, Yang R, Wang H, Xu W, Yin Y, Zhang X. ΔA146Ply-HA stem protein immunization protects mice against influenza A virus infection and co-infection with Streptococcus pneumoniae. Mol Immunol 2023; 161:91-103. [PMID: 37531919 DOI: 10.1016/j.molimm.2023.07.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/30/2023] [Accepted: 07/18/2023] [Indexed: 08/04/2023]
Abstract
Influenza virus (IV) is a common pathogen affecting the upper respiratory tract, that causes various diseases. Secondary bacterial pneumonia is a common complication and a major cause of death in influenza patients. Streptococcus pneumoniae (S. pneumoniae) is the predominant co-infected bacteria in the pandemic, which colonizes healthy people but can cause diseases in immunocompromised individuals. Vaccination is a crucial strategy for avoiding infection, however, no universal influenza vaccine (UIV) that is resistant to multiple influenza viruses is available. Despite its limited immunogenicity, the hemagglutinin (HA) stem is a candidate peptide for UIV. ΔA146Ply (pneumolysin with a single deletion of A146) not only retains the Toll-like receptor 4 agonist effect but also is a potential vaccine adjuvant and a candidate protein for the S. pneumoniae vaccine. We constructed the fusion protein ΔA146Ply-HA stem and studied its immunoprotective effect in mice infection models. The results showed that intramuscular immunization of ΔA146Ply-HA stem without adjuvant could induce specific antibodies against HA stem and specific CD4+ T and CD8+ T cellular immunity in BALB/c and C57BL/6 mice, which could improve the survival rate of mice infected with IAV and co-infected with S. pneumoniae, but the protective effect on BALB/c mice was better than that on C57BL/6 mice. ΔA146Ply-HA stem serum antibody could protect BALB/c and C57BL/6 mice from IAV, and recognized HA polypeptides of H3N2, H5N1, H7N9, and H9N2 viruses. Moreover, ΔA146Ply-HA stem intramuscular immunization had a high safety profile with no obvious toxic side effects. The results indicated that coupling ΔA146Ply with influenza protein as a vaccine was a safe and effective strategy against the IV and secondary S. pneumoniae infection.
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Affiliation(s)
- Lian Li
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University, Chongqing 400016, China
| | - Ting Guo
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University, Chongqing 400016, China
| | - Yuan Yuan
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University, Chongqing 400016, China
| | - Jiangming Xiao
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University, Chongqing 400016, China
| | - Rui Yang
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University, Chongqing 400016, China
| | - Hanyi Wang
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University, Chongqing 400016, China
| | - Wenlong Xu
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University, Chongqing 400016, China
| | - Yibing Yin
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University, Chongqing 400016, China
| | - Xuemei Zhang
- Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University, Chongqing 400016, China.
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25
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Tsui HCT, Joseph M, Zheng JJ, Perez AJ, Manzoor I, Rued BE, Richardson JD, Branny P, Doubravová L, Massidda O, Winkler ME. Negative regulation of MurZ and MurA underlies the essentiality of GpsB- and StkP-mediated protein phosphorylation in Streptococcus pneumoniae D39. Mol Microbiol 2023; 120:351-383. [PMID: 37452010 PMCID: PMC10530524 DOI: 10.1111/mmi.15122] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 07/18/2023]
Abstract
GpsB links peptidoglycan synthases to other proteins that determine the shape of the respiratory pathogen Streptococcus pneumoniae (pneumococcus; Spn) and other low-GC Gram-positive bacteria. GpsB is also required for phosphorylation of proteins by the essential StkP(Spn) Ser/Thr protein kinase. Here we report three classes of frequently arising chromosomal duplications (≈21-176 genes) containing murZ (MurZ-family homolog of MurA) or murA that suppress ΔgpsB or ΔstkP. These duplications arose from three different repeated sequences and demonstrate the facility of pneumococcus to modulate gene dosage of numerous genes. Overproduction of MurZ or MurA alone or overproduction of MurZ caused by ΔkhpAB mutations suppressed ΔgpsB or ΔstkP phenotypes to varying extents. ΔgpsB and ΔstkP were also suppressed by MurZ amino-acid changes distant from the active site, including one in commonly studied laboratory strains, and by truncation or deletion of the homolog of IreB(ReoM). Unlike in other Gram-positive bacteria, MurZ is predominant to MurA in pneumococcal cells. However, ΔgpsB and ΔstkP were not suppressed by ΔclpCP, which did not alter MurZ or MurA amounts. These results support a model in which regulation of MurZ and MurA activity, likely by IreB(Spn), is the only essential requirement for StkP-mediated protein phosphorylation in exponentially growing D39 pneumococcal cells.
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Affiliation(s)
| | - Merrin Joseph
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Jiaqi J. Zheng
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Amilcar J. Perez
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Irfan Manzoor
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Britta E. Rued
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - John D. Richardson
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Pavel Branny
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Linda Doubravová
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Orietta Massidda
- Department of Cellular, Computational, and Integrative Biology, University of Trento, Italy
| | - Malcolm E. Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
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26
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Battista M, Hoffmann B, Bachelot Y, Zimmermann L, Teuber L, Jost A, Linde S, Westermann M, Müller MM, Slevogt H, Hammerschmidt S, Figge MT, Vilhena C, Zipfel PF. The role of pneumococcal extracellular vesicles on the pathophysiology of the kidney disease hemolytic uremic syndrome. mSphere 2023; 8:e0014223. [PMID: 37358300 PMCID: PMC10449520 DOI: 10.1128/msphere.00142-23] [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: 04/11/2023] [Accepted: 04/20/2023] [Indexed: 06/27/2023] Open
Abstract
Streptococcus pneumoniae-induced hemolytic uremic syndrome (Sp-HUS) is a kidney disease characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. This disease is frequently underdiagnosed and its pathophysiology is poorly understood. In this work, we compared clinical strains, isolated from infant Sp-HUS patients, with a reference pathogenic strain D39, for host cytotoxicity and further explored the role of Sp-derived extracellular vesicles (EVs) in the pathogenesis of an HUS infection. In comparison with the wild-type strain, pneumococcal HUS strains caused significant lysis of human erythrocytes and increased the release of hydrogen peroxide. Isolated Sp-HUS EVs were characterized by performing dynamic light-scattering microscopy and proteomic analysis. Sp-HUS strain released EVs at a constant concentration during growth, yet the size of the EVs varied and several subpopulations emerged at later time points. The cargo of the Sp-HUS EVs included several virulence factors at high abundance, i.e., the ribosomal subunit assembly factor BipA, the pneumococcal surface protein A, the lytic enzyme LytC, several sugar utilization, and fatty acid synthesis proteins. Sp-HUS EVs strongly downregulated the expression of the endothelial surface marker platelet endothelial cell adhesion molecule-1 and were internalized by human endothelial cells. Sp-HUS EVs elicited the release of pro-inflammatory cytokines (interleukin [IL]-1β, IL-6) and chemokines (CCL2, CCL3, CXCL1) by human monocytes. These findings shed new light on the overall function of Sp-EVs, in the scope of infection-mediated HUS, and suggest new avenues of research for exploring the usefulness of Sp-EVs as therapeutic and diagnostic targets. IMPORTANCE Streptococcus pneumoniae-associated hemolytic uremic syndrome (Sp-HUS) is a serious and underdiagnosed deadly complication of invasive pneumococcal disease. Despite the introduction of the pneumococcal vaccine, cases of Sp-HUS continue to emerge, especially in children under the age of 2. While a lot has been studied regarding pneumococcal proteins and their role on Sp-HUS pathophysiology, little is known about the role of extracellular vesicles (EVs). In our work, we isolate and initially characterize EVs from a reference pathogenic strain (D39) and a strain isolated from a 2-year-old patient suffering from Sp-HUS. We demonstrate that despite lacking cytotoxicity toward human cells, Sp-HUS EVs are highly internalized by endothelial cells and can trigger cytokine and chemokine production in monocytes. In addition, this work specifically highlights the distinct morphological characteristics of Sp-HUS EVs and their unique cargo. Overall, this work sheds new light into potentially relevant players contained in EVs that might elucidate about pneumococcal EVs biogenesis or pose as interesting candidates for vaccine design.
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Affiliation(s)
- Miriana Battista
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Bianca Hoffmann
- Applied Systems Biology, HKI-Center for Systems Biology of Infection, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI), Jena, Germany
| | - Yann Bachelot
- Applied Systems Biology, HKI-Center for Systems Biology of Infection, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI), Jena, Germany
| | - Lioba Zimmermann
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Laura Teuber
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Aurélie Jost
- Microverse Imaging Center, Cluster of Excellence “Balance of the Microverse,” Friedrich Schiller University, Jena, Germany
| | - Susanne Linde
- Center for Electron Microscopy, Jena University Hospital, Jena, Germany
| | - Martin Westermann
- Center for Electron Microscopy, Jena University Hospital, Jena, Germany
| | - Mario M. Müller
- Septomics Research Center, Jena University Hospital, Jena, Germany
| | - Hortense Slevogt
- Septomics Research Center, Jena University Hospital, Jena, Germany
| | - 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, Greifswald, Germany
| | - Marc Thilo Figge
- Applied Systems Biology, HKI-Center for Systems Biology of Infection, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI), Jena, Germany
- Faculty of Biological Sciences, Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Cláudia Vilhena
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Peter F. Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
- Faculty of Biological Sciences, Institute of Microbiology, Friedrich Schiller University, Jena, Germany
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27
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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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28
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Zhang C, Liu Y, An H, Wang X, Xu L, Deng H, Wu S, Zhang JR, Liu X. Amino Acid Starvation-Induced Glutamine Accumulation Enhances Pneumococcal Survival. mSphere 2023; 8:e0062522. [PMID: 37017541 PMCID: PMC10286718 DOI: 10.1128/msphere.00625-22] [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: 12/06/2022] [Accepted: 02/19/2023] [Indexed: 04/06/2023] Open
Abstract
Bacteria are known to cope with amino acid starvation by the stringent response signaling system, which is mediated by the accumulation of the (p)ppGpp alarmones when uncharged tRNAs stall at the ribosomal A site. While a number of metabolic processes have been shown to be regulatory targets of the stringent response in many bacteria, the global impact of amino acid starvation on bacterial metabolism remains obscure. This work reports the metabolomic profiling of the human pathogen Streptococcus pneumoniae under methionine starvation. Methionine limitation led to the massive overhaul of the pneumococcal metabolome. In particular, methionine-starved pneumococci showed a massive accumulation of many metabolites such as glutamine, glutamic acid, lactate, and cyclic AMP (cAMP). In the meantime, methionine-starved pneumococci showed a lower intracellular pH and prolonged survival. Isotope tracing revealed that pneumococci depend predominantly on amino acid uptake to replenish intracellular glutamine but cannot convert glutamine to methionine. Further genetic and biochemical analyses strongly suggested that glutamine is involved in the formation of a "prosurvival" metabolic state by maintaining an appropriate intracellular pH, which is accomplished by the enzymatic release of ammonia from glutamine. Methionine starvation-induced intracellular pH reduction and glutamine accumulation also occurred to various extents under the limitation of other amino acids. These findings have uncovered a new metabolic mechanism of bacterial adaptation to amino acid limitation and perhaps other stresses, which may be used as a potential therapeutic target for infection control. IMPORTANCE Bacteria are known to cope with amino acid starvation by halting growth and prolonging survival via the stringent response signaling system. Previous investigations have allowed us to understand how the stringent response regulates many aspects of macromolecule synthesis and catabolism, but how amino acid starvation promotes bacterial survival at the metabolic level remains largely unclear. This paper reports our systematic profiling of the methionine starvation-induced metabolome in S. pneumoniae. To the best of our knowledge, this represents the first reported bacterial metabolome under amino acid starvation. These data have revealed that the significant accumulation of glutamine and lactate enables S. pneumoniae to form a "prosurvival" metabolic state with a lower intracellular pH, which inhibits bacterial growth for prolonged survival. Our findings have provided insightful information on the metabolic mechanisms of pneumococcal adaptation to nutrient limitation during the colonization of the human upper airway.
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Affiliation(s)
- Chengwang Zhang
- Department of Basic Medical Science, School of Medicine, Lishui University, Lishui, Zhejiang, China
| | - Yanhong Liu
- Center for Infectious Disease Research, Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China
| | - Haoran An
- Center for Infectious Disease Research, Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
| | - Xueying Wang
- National Protein Science Facility, Tsinghua University, Beijing, China
| | - Lina Xu
- National Protein Science Facility, Tsinghua University, Beijing, China
| | - Haiteng Deng
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Songquan Wu
- Department of Basic Medical Science, School of Medicine, Lishui University, Lishui, Zhejiang, China
| | - Jing-Ren Zhang
- Center for Infectious Disease Research, Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
| | - Xiaohui Liu
- National Protein Science Facility, Tsinghua University, Beijing, China
- School of Life Sciences, Tsinghua University, Beijing, China
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29
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Scasny A, Alibayov B, Khan F, Rao SJ, Murin L, Jop Vidal AG, Smith P, Wei L, Edwards K, Warncke K, Vidal JE. Oxidation of hemoproteins by Streptococcus pneumoniae collapses the cell cytoskeleton and disrupts mitochondrial respiration leading to cytotoxicity of human lung cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.07.544089. [PMID: 37333138 PMCID: PMC10274756 DOI: 10.1101/2023.06.07.544089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Streptococcus pneumoniae (Spn) causes pneumonia that kills millions through acute toxicity and invasion of the lung parenchyma. During aerobic respiration, Spn releases hydrogen peroxide (Spn-H 2 O 2 ), as a by-product of enzymes SpxB and LctO, and causes cell death with signs of both apoptosis and pyroptosis by oxidizing unknown cell targets. Hemoproteins are molecules essential for life and prone to oxidation by H 2 O 2 . We recently demonstrated that during infection-mimicking conditions, Spn-H 2 O 2 oxidizes the hemoprotein hemoglobin (Hb), releasing toxic heme. In this study, we investigated details of the molecular mechanism(s) by which the oxidation of hemoproteins by Spn-H 2 O 2 causes human lung cell death. Spn strains, but not H 2 O 2 -deficient SpnΔ spxB Δ lctO strains caused time-dependent cell cytotoxicity characterized by the rearrangement of the actin, the loss of the microtubule cytoskeleton and nuclear contraction. Disruption of the cell cytoskeleton correlated with the presence of invasive pneumococci and an increase of intracellular reactive oxygen species. In cell culture, the oxidation of Hb or cytochrome c (Cyt c ) caused DNA degradation and mitochondrial dysfunction from inhibition of complex I-driven respiration, which was cytotoxic to human alveolar cells. Oxidation of hemoproteins resulted in the creation of a radical, which was identified as a protein derived side chain tyrosyl radical by using electron paramagnetic resonance (EPR). Thus, we demonstrate that Spn invades lung cells, releasing H 2 O 2 that oxidizes hemoproteins, including Cyt c , catalyzing the formation of a tyrosyl side chain radical on Hb and causing mitochondrial disruption, that ultimately leads to the collapse of the cell cytoskeleton.
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Heithoff DM, Barnes V L, Mahan SP, Fried JC, Fitzgibbons LN, House JK, Mahan MJ. Re-evaluation of FDA-approved antibiotics with increased diagnostic accuracy for assessment of antimicrobial resistance. Cell Rep Med 2023; 4:101023. [PMID: 37116500 PMCID: PMC10213814 DOI: 10.1016/j.xcrm.2023.101023] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 02/16/2023] [Accepted: 04/05/2023] [Indexed: 04/30/2023]
Abstract
Accurate assessment of antibiotic susceptibility is critical for treatment of antimicrobial resistant (AMR) infections. Here, we examine whether antimicrobial susceptibility testing in media more physiologically representative of in vivo conditions improves prediction of clinical outcome relative to standard bacteriologic medium. This analysis reveals that ∼15% of minimum inhibitory concentration (MIC) values obtained in physiologic media predicted a change in susceptibility that crossed a clinical breakpoint used to categorize patient isolates as susceptible or resistant. The activities of antibiotics having discrepant results in different media were evaluated in murine sepsis models. Testing in cell culture medium improves the accuracy by which MIC assays predict in vivo efficacy. This analysis identifies several antibiotics for treatment of AMR infections that standard testing failed to identify and those that are ineffective despite indicated use by standard testing. Methods with increased diagnostic accuracy mitigate the AMR crisis via utilizing existing agents and optimizing drug discovery.
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Affiliation(s)
- Douglas M Heithoff
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA; Institute for Collaborative Biotechnologies, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Lucien Barnes V
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA; Institute for Collaborative Biotechnologies, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Scott P Mahan
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA; Institute for Collaborative Biotechnologies, University of California, Santa Barbara, Santa Barbara, CA 93106, USA; Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, Davis, CA 95616, USA
| | - Jeffrey C Fried
- Department of Medical Education, Santa Barbara Cottage Hospital, Santa Barbara, CA 93105, USA; Department of Pulmonary and Critical Care Medicine, Santa Barbara Cottage Hospital, Santa Barbara, CA 93105, USA
| | - Lynn N Fitzgibbons
- Department of Medical Education, Santa Barbara Cottage Hospital, Santa Barbara, CA 93105, USA; Division of Infectious Diseases, Santa Barbara Cottage Hospital, Santa Barbara, CA 93105, USA
| | - John K House
- Faculty of Science, School of Veterinary Science, The University of Sydney, Camden, NSW 2570, Australia.
| | - Michael J Mahan
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA; Institute for Collaborative Biotechnologies, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
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31
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Shami A, Alharbi NK, Al-Saeed FA, Alsaegh AA, Al Syaad KM, Abd El-Rahim IHA, Mostafa YS, Ahmed AE. In Silico Subtractive Proteomics and Molecular Docking Approaches for the Identification of Novel Inhibitors against Streptococcus pneumoniae Strain D39. Life (Basel) 2023; 13:life13051128. [PMID: 37240772 DOI: 10.3390/life13051128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/10/2023] [Accepted: 04/25/2023] [Indexed: 05/28/2023] Open
Abstract
Streptococcus pneumoniae is a notorious Gram-positive pathogen present asymptomatically in the nasophayrnx of humans. According to the World Health Organization (W.H.O), pneumococcus causes approximately one million deaths yearly. Antibiotic resistance in S. pneumoniae is raising considerable concern around the world. There is an immediate need to address the major issues that have arisen as a result of persistent infections caused by S. pneumoniae. In the present study, subtractive proteomics was used in which the entire proteome of the pathogen consisting of 1947 proteins is effectively decreased to a finite number of possible targets. Various kinds of bioinformatics tools and software were applied for the discovery of novel inhibitors. The CD-HIT analysis revealed 1887 non-redundant sequences from the entire proteome. These non-redundant proteins were submitted to the BLASTp against the human proteome and 1423 proteins were screened as non-homologous. Further, databases of essential genes (DEGG) and J browser identified almost 171 essential proteins. Moreover, non-homologous, essential proteins were subjected in KEGG Pathway Database which shortlisted six unique proteins. In addition, the subcellular localization of these unique proteins was checked and cytoplasmic proteins were chosen for the druggability analysis, which resulted in three proteins, namely DNA binding response regulator (SPD_1085), UDP-N-acetylmuramate-L-alanine Ligase (SPD_1349) and RNA polymerase sigma factor (SPD_0958), which can act as a promising potent drug candidate to limit the toxicity caused by S. pneumoniae. The 3D structures of these proteins were predicted by Swiss Model, utilizing the homology modeling approach. Later, molecular docking by PyRx software 0.8 version was used to screen a library of phytochemicals retrieved from PubChem and ZINC databases and already approved drugs from DrugBank database against novel druggable targets to check their binding affinity with receptor proteins. The top two molecules from each receptor protein were selected based on the binding affinity, RMSD value, and the highest conformation. Finally, the absorption, distribution, metabolism, excretion, and toxicity (ADMET) analyses were carried out by utilizing the SWISS ADME and Protox tools. This research supported the discovery of cost-effective drugs against S. pneumoniae. However, more in vivo/in vitro research should be conducted on these targets to investigate their pharmacological efficacy and their function as efficient inhibitors.
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Affiliation(s)
- Ashwag Shami
- Department of Biology, College of Sciences, Princess Nourah Bint Abdulrahman University, Riyadh 11617, Saudi Arabia
| | - Nada K Alharbi
- Department of Biology, College of Sciences, Princess Nourah Bint Abdulrahman University, Riyadh 11617, Saudi Arabia
| | - Fatimah A Al-Saeed
- Research Centre, Department of Biology, College of Science, King Khalid University, Abha 61413, Saudi Arabia
- Advanced Material Science (RCAMS), King Khalid University, Abha 61413, Saudi Arabia
| | - Aiman A Alsaegh
- Department of Laboratory Medicine, Faculty of Applied Medical Sciences, Umm Al-Qura University, Makkah Al-Mukarramah 24382, Saudi Arabia
| | - Khalid M Al Syaad
- Biology Department, Faculty of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia
- The Research Center, Faculty of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia
| | - Ibrahim H A Abd El-Rahim
- Department of Environmental and Health Research, Umm Al-Qura University, P.O. Box 6287, Makkah Al-Mukarramah 21955, Saudi Arabia
| | - Yasser Sabry Mostafa
- Biology Department, Faculty of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia
| | - Ahmed Ezzat Ahmed
- Biology Department, Faculty of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia
- Department of Theriogenology, Faculty of Veterinary Medicine, South Valley University, Qena 83523, Egypt
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Kant S, Sun Y, Pancholi V. StkP- and PhpP-Mediated Posttranslational Modifications Modulate the S. pneumoniae Metabolism, Polysaccharide Capsule, and Virulence. Infect Immun 2023; 91:e0029622. [PMID: 36877045 PMCID: PMC10112228 DOI: 10.1128/iai.00296-22] [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: 07/15/2022] [Accepted: 02/09/2023] [Indexed: 03/07/2023] Open
Abstract
Pneumococcal Ser/Thr kinase (StkP) and its cognate phosphatase (PhpP) play a crucial role in bacterial cytokinesis. However, their individual and reciprocal metabolic and virulence regulation-related functions have yet to be adequately investigated in encapsulated pneumococci. Here, we demonstrate that the encapsulated pneumococcal strain D39-derived D39ΔPhpP and D39ΔStkP mutants displayed differential cell division defects and growth patterns when grown in chemically defined media supplemented with glucose or nonglucose sugars as the sole carbon source. Microscopic and biochemical analyses supported by RNA-seq-based global transcriptomic analyses of these mutants revealed significantly down- and upregulated polysaccharide capsule formation and cps2 genes in D39ΔPhpP and D39ΔStkP mutants, respectively. While StkP and PhpP individually regulated several unique genes, they also participated in sharing the regulation of the same set of differentially regulated genes. Cps2 genes were reciprocally regulated in part by the StkP/PhpP-mediated reversible phosphorylation but independent of the MapZ-regulated cell division process. StkP-mediated dose-dependent phosphorylation of CcpA proportionately inhibited CcpA-binding to Pcps2A, supporting increased cps2 gene expression and capsule formation in D39ΔStkP. While the attenuation of the D39ΔPhpP mutant in two mouse infection models corroborated with several downregulated capsules-, virulence-, and phosphotransferase systems (PTS)-related genes, the D39ΔStkP mutant with increased amounts of polysaccharide capsules displayed significantly decreased virulence in mice compared to the D39 wild-type, but more virulence compared to D39ΔPhpP. NanoString technology-based inflammation-related gene expression and Meso Scale Discovery-based multiplex chemokine analysis of human lung cells cocultured with these mutants confirmed their distinct virulence phenotypes. StkP and PhpP may, therefore, serve as critical therapeutic targets.
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Affiliation(s)
- Sashi Kant
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Youcheng Sun
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Vijay Pancholi
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, USA
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Tsui HCT, Joseph M, Zheng JJ, Perez AJ, Manzoor I, Rued BE, Richardson JD, Branny P, Doubravová L, Massidda O, Winkler ME. Chromosomal Duplications of MurZ (MurA2) or MurA (MurA1), Amino Acid Substitutions in MurZ (MurA2), and Absence of KhpAB Obviate the Requirement for Protein Phosphorylation in Streptococcus pneumoniae D39. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.26.534294. [PMID: 37034771 PMCID: PMC10081211 DOI: 10.1101/2023.03.26.534294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
GpsB links peptidoglycan synthases to other proteins that determine the shape of the respiratory pathogen Streptococcus pneumoniae (pneumococcus; Spn ) and other low-GC Gram-positive bacteria. GpsB is also required for phosphorylation of proteins by the essential StkP( Spn ) Ser/Thr protein kinase. Here we report three classes of frequently arising chromosomal duplications (≈21-176 genes) containing murZ (MurZ-family homolog of MurA) or murA that suppress Δ gpsB or Δ stkP . These duplications arose from three different repeated sequences and demonstrate the facility of pneumococcus to modulate gene dosage of numerous genes. Overproduction of MurZ or MurA alone or overexpression of MurZ caused by Δ khpAB mutations suppressed Δ gpsB or Δ stkP phenotypes to varying extents. Δ gpsB and Δ stkP were also suppressed by MurZ amino-acid changes distant from the active site, including one in commonly studied laboratory strains, and by truncation or deletion of the homolog of IreB(ReoM). Unlike in other Gram-positive bacteria, MurZ is predominant to MurA in pneumococcal cells. However, Δ gpsB and Δ stkP were not suppressed by Δ clpCP , which did not alter MurZ or MurA amounts. These results support a model in which regulation of MurZ and MurA activity, likely by IreB( Spn ), is the only essential requirement for protein phosphorylation in exponentially growing D39 pneumococcal cells.
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34
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Mitchell SL, Kearns DB, Carlson EE. Penicillin-binding protein redundancy in Bacillus subtilis enables growth during alkaline shock. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.20.533529. [PMID: 36993441 PMCID: PMC10055284 DOI: 10.1101/2023.03.20.533529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Penicillin-binding proteins (PBPs) play critical roles in cell wall construction, cell shape, and bacterial replication. Bacteria maintain a diversity of PBPs, indicating that despite their apparent functional redundancy, there is differentiation across the PBP family. Seemingly redundant proteins can be important for enabling an organism to cope with environmental stressors. We sought to evaluate the consequence of environmental pH on PBP enzymatic activity in Bacillus subtilis. Our data show that a subset of B. subtilis PBPs change activity levels during alkaline shock and that one PBP isoform is rapidly modified to generate a smaller protein (i.e., PBP1a to PBP1b). Our results indicate that a subset of the PBPs are preferred for growth under alkaline conditions, while others are readily dispensable. Indeed, we found that this phenomenon could also be observed in Streptococcus pneumoniae, implying that it may be generalizable across additional bacterial species and further emphasizing the evolutionary benefit of maintaining many, seemingly redundant periplasmic enzymes.
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Affiliation(s)
| | - Daniel B. Kearns
- Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - Erin E. Carlson
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455
- Departments of Medicinal Chemistry, Biochemistry, Molecular Biology and Biophysics, and Pharmacology, University of Minnesota, Minneapolis, Minnesota 55455
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35
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Ortiz-Miravalles L, Sánchez-Angulo M, Sanz JM, Maestro B. Drug Repositioning as a Therapeutic Strategy against Streptococcus pneumoniae: Cell Membrane as Potential Target. Int J Mol Sci 2023; 24:ijms24065831. [PMID: 36982905 PMCID: PMC10058218 DOI: 10.3390/ijms24065831] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/14/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
A collection of repurposing drugs (Prestwick Chemical Library) containing 1200 compounds was screened to investigate the drugs' antimicrobial effects against planktonic cultures of the respiratory pathogen Streptococcus pneumoniae. After four discrimination rounds, a set of seven compounds was finally selected, namely (i) clofilium tosylate; (ii) vanoxerine; (iii) mitoxantrone dihydrochloride; (iv) amiodarone hydrochloride; (v) tamoxifen citrate; (vi) terfenadine; and (vii) clomiphene citrate (Z, E). These molecules arrested pneumococcal growth in a liquid medium and induced a decrease in bacterial viability between 90.0% and 99.9% at 25 µM concentration, with minimal inhibitory concentrations (MICs) also in the micromolar range. Moreover, all compounds but mitoxantrone caused a remarkable increase in the permeability of the bacterial membrane and share a common, minimal chemical structure consisting of an aliphatic amine linked to a phenyl moiety via a short carbon/oxygen linker. These results open new possibilities to tackle pneumococcal disease through drug repositioning and provide clues for the design of novel membrane-targeted antimicrobials with a related chemical structure.
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Affiliation(s)
- Laura Ortiz-Miravalles
- Protein Engineering against Antimicrobial Resistance Group, Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid, Spain
- Department of Animal Health, Faculty of Veterinary Medicine, Universidad Complutense de Madrid, 28040 Madrid, Spain
- VISAVET Health Surveillance Centre, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Manuel Sánchez-Angulo
- Department of Vegetal Production and Microbiology, Universidad Miguel Hernández, 03202 Elche, Spain
| | - Jesús M Sanz
- Protein Engineering against Antimicrobial Resistance Group, Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Beatriz Maestro
- Protein Engineering against Antimicrobial Resistance Group, Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid, Spain
- Department of Biochemistry and Molecular Biology, Faculty of Biology, Universidad Complutense de Madrid (UCM), 28040 Madrid, Spain
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36
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De S, Hakansson AP. Measuring Niche-Associated Metabolic Activity in Planktonic and Biofilm Bacteria. Methods Mol Biol 2023; 2674:3-32. [PMID: 37258957 DOI: 10.1007/978-1-0716-3243-7_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Most pathobionts of the respiratory tract form biofilms during asymptomatic colonization to survive and persist in this niche. Environmental changes of the host niche, often resulting from infection with respiratory viruses, changes of the microbiota composition, or other host assaults, can result in biofilm dispersion and spread of bacteria to other host niches, resulting in infections, such as otitis media, pneumonia, sepsis, and meningitis. The niches that these bacteria encounter during colonization and infection vary markedly in nutritional availability and contain different carbon sources and levels of other essential nutrients needed for bacterial growth and survival. As these niche-related nutritional variations regulate bacterial behavior and phenotype, a better understanding of bacterial niche-associated metabolic activity is likely to provide a broader understanding of bacterial pathogenesis. In this chapter, we use Streptococcus pneumoniae as a model respiratory pathobiont. We describe methods and models used to grow bacteria planktonically or to form biofilms in vitro by incorporating crucial host environmental factors, including the various carbon sources associated with specific niches, such as the nasopharynx or bloodstream. We then present methods describing how these models can be used to study bacterial phenotypes and their association with metabolic energy production and the generation of fermentation products.
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Affiliation(s)
- Supradipta De
- Department of Translational Medicine, Division of Experimental Infection Medicine, Wallenberg Laboratory, Lund University, Malmö, Sweden
| | - Anders P Hakansson
- Department of Translational Medicine, Division of Experimental Infection Medicine, Wallenberg Laboratory, Lund University, Malmö, Sweden.
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37
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Glanville DG, Gazioglu O, Marra M, Tokars VL, Kushnir T, Habtom M, Croucher NJ, Nebenzahl YM, Mondragón A, Yesilkaya H, Ulijasz AT. Pneumococcal capsule expression is controlled through a conserved, distal cis-regulatory element during infection. PLoS Pathog 2023; 19:e1011035. [PMID: 36719895 PMCID: PMC9888711 DOI: 10.1371/journal.ppat.1011035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 11/29/2022] [Indexed: 02/01/2023] Open
Abstract
Streptococcus pneumoniae (the pneumococcus) is the major cause of bacterial pneumonia in the US and worldwide. Studies have shown that the differing chemical make-up between serotypes of its most important virulence factor, the capsule, can dictate disease severity. Here we demonstrate that control of capsule synthesis is also critical for infection and facilitated by two broadly conserved transcription factors, SpxR and CpsR, through a distal cis-regulatory element we name the 37-CE. Strikingly, changing only three nucleotides within this sequence is sufficient to render pneumococcus avirulent. Using in vivo and in vitro approaches, we present a model where SpxR interacts as a unique trimeric quaternary structure with the 37-CE to enable capsule repression in the airways. Considering its dramatic effect on infection, variation of the 37-CE between serotypes suggests this molecular switch could be a critical contributing factor to this pathogen's serotype-specific disease outcomes.
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Affiliation(s)
- David G. Glanville
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois, United States of America
| | - Ozcan Gazioglu
- Department of Respiratory Sciences, University of Leicester, University Road, Leicester, United Kingdom
| | - Michela Marra
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois, United States of America
| | - Valerie L. Tokars
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Tatyana Kushnir
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of The Negev, Beer-Sheva, Israel
| | - Medhanie Habtom
- Department of Respiratory Sciences, University of Leicester, University Road, Leicester, United Kingdom
| | - Nicholas J. Croucher
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Sir Michael Uren Hub, Imperial College London, London, United Kingdom
| | - Yaffa Mizrachi Nebenzahl
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of The Negev, Beer-Sheva, Israel
| | - Alfonso Mondragón
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
| | - Hasan Yesilkaya
- Department of Respiratory Sciences, University of Leicester, University Road, Leicester, United Kingdom
| | - Andrew T. Ulijasz
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois, United States of America
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38
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AmiA and AliA peptide ligands are secreted by Klebsiella pneumoniae and inhibit growth of Streptococcus pneumoniae. Sci Rep 2022; 12:22268. [PMID: 36564446 PMCID: PMC9789142 DOI: 10.1038/s41598-022-26838-z] [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: 06/30/2022] [Accepted: 12/21/2022] [Indexed: 12/24/2022] Open
Abstract
Streptococcus pneumoniae colonizes the human nasopharynx, a multi-species microbial niche. Pneumococcal Ami-AliA/AliB oligopeptide permease is an ABC transporter involved in environmental sensing with peptides AKTIKITQTR, FNEMQPIVDRQ, and AIQSEKARKHN identified as ligands of its substrate binding proteins AmiA, AliA, and AliB, respectively. These sequences match ribosomal proteins of multiple bacterial species, including Klebsiella pneumoniae. By mass spectrometry, we identified such peptides in the Klebsiella pneumoniae secretome. AmiA and AliA peptide ligands suppressed pneumococcal growth, but the effect was dependent on peptide length. Growth was suppressed for diverse pneumococci, including antibiotic-resistant strains, but not other bacterial species tested, with the exception of Streptococcus pseudopneumoniae, whose growth was suppressed by the AmiA peptide ligand. By multiple sequence alignments and protein and peptide binding site predictions, for AmiA we have identified the location of an amino acid in the putative binding site whose mutation appears to result in loss of response to the peptide. Our results indicate that pneumococci sense the presence of Klebsiella pneumoniae peptides in the environment.
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39
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Kwun MJ, Ion AV, Cheng HC, D’Aeth JC, Dougan S, Oggioni MR, Goulding DA, Bentley SD, Croucher NJ. Post-vaccine epidemiology of serotype 3 pneumococci identifies transformation inhibition through prophage-driven alteration of a non-coding RNA. Genome Med 2022; 14:144. [PMID: 36539881 PMCID: PMC9764711 DOI: 10.1186/s13073-022-01147-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 11/29/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND The respiratory pathogen Streptococcus pneumoniae (the pneumococcus) is a genetically diverse bacterium associated with over 101 immunologically distinct polysaccharide capsules (serotypes). Polysaccharide conjugate vaccines (PCVs) have successfully eliminated multiple targeted serotypes, yet the mucoid serotype 3 has persisted despite its inclusion in PCV13. This capsule type is predominantly associated with a single globally disseminated strain, GPSC12 (clonal complex 180). METHODS A genomic epidemiology study combined previous surveillance datasets of serotype 3 pneumococci to analyse the population structure, dynamics, and differences in rates of diversification within GPSC12 during the period of PCV introductions. Transcriptomic analyses, whole genome sequencing, mutagenesis, and electron microscopy were used to characterise the phenotypic impact of loci hypothesised to affect this strain's evolution. RESULTS GPSC12 was split into clades by a genomic analysis. Clade I, the most common, rarely underwent transformation, but was typically infected with the prophage ϕOXC141. Prior to the introduction of PCV13, this clade's composition shifted towards a ϕOXC141-negative subpopulation in a systematically sampled UK collection. In the post-PCV13 era, more rapidly recombining non-Clade I isolates, also ϕOXC141-negative, have risen in prevalence. The low in vitro transformation efficiency of a Clade I isolate could not be fully explained by the ~100-fold reduction attributable to the serotype 3 capsule. Accordingly, prophage ϕOXC141 was found to modify csRNA3, a non-coding RNA that inhibits the induction of transformation. This alteration was identified in ~30% of all pneumococci and was particularly common in the unusually clonal serotype 1 GPSC2 strain. RNA-seq and quantitative reverse transcriptase PCR experiments using a genetically tractable pneumococcus demonstrated the altered csRNA3 was more effective at inhibiting production of the competence-stimulating peptide pheromone. This resulted in a reduction in the induction of competence for transformation. CONCLUSION This interference with the quorum sensing needed to induce competence reduces the risk of the prophage being deleted by homologous recombination. Hence the selfish prophage-driven alteration of a regulatory RNA limits cell-cell communication and horizontal gene transfer, complicating the interpretation of post-vaccine population dynamics.
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Affiliation(s)
- Min Jung Kwun
- grid.7445.20000 0001 2113 8111MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, White City Campus, Imperial College London, London, W12 0BZ UK
| | - Alexandru V. Ion
- grid.7445.20000 0001 2113 8111MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, White City Campus, Imperial College London, London, W12 0BZ UK
| | - Hsueh-Chien Cheng
- grid.10306.340000 0004 0606 5382Parasites & Microbes, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA UK
| | - Joshua C. D’Aeth
- grid.7445.20000 0001 2113 8111MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, White City Campus, Imperial College London, London, W12 0BZ UK
| | - Sam Dougan
- grid.10306.340000 0004 0606 5382Parasites & Microbes, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA UK
| | - Marco R. Oggioni
- grid.9918.90000 0004 1936 8411Department of Genetics, University of Leicester, University Road, Leicester, LE1 7RH UK ,grid.6292.f0000 0004 1757 1758Dipartimento di Farmacia e Biotecnologie, Università di Bologna, Via Irnerio 42, 40126 Bologna, Italy
| | - David A. Goulding
- grid.10306.340000 0004 0606 5382Parasites & Microbes, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA UK
| | - Stephen D. Bentley
- grid.10306.340000 0004 0606 5382Parasites & Microbes, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA UK
| | - Nicholas J. Croucher
- grid.7445.20000 0001 2113 8111MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, White City Campus, Imperial College London, London, W12 0BZ UK
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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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41
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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: 11] [Impact Index Per Article: 5.5] [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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Rosconi F, Rudmann E, Li J, Surujon D, Anthony J, Frank M, Jones DS, Rock C, Rosch JW, Johnston CD, van Opijnen T. A bacterial pan-genome makes gene essentiality strain-dependent and evolvable. Nat Microbiol 2022; 7:1580-1592. [PMID: 36097170 PMCID: PMC9519441 DOI: 10.1038/s41564-022-01208-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 07/21/2022] [Indexed: 11/09/2022]
Abstract
Many bacterial species are represented by a pan-genome, whose genetic repertoire far outstrips that of any single bacterial genome. Here we investigate how a bacterial pan-genome might influence gene essentiality and whether essential genes that are initially critical for the survival of an organism can evolve to become non-essential. By using Transposon insertion sequencing (Tn-seq), whole-genome sequencing and RNA-seq on a set of 36 clinical Streptococcus pneumoniae strains representative of >68% of the species' pan-genome, we identify a species-wide 'essentialome' that can be subdivided into universal, core strain-specific and accessory essential genes. By employing 'forced-evolution experiments', we show that specific genetic changes allow bacteria to bypass essentiality. Moreover, by untangling several genetic mechanisms, we show that gene essentiality can be highly influenced by and/or be dependent on: (1) the composition of the accessory genome, (2) the accumulation of toxic intermediates, (3) functional redundancy, (4) efficient recycling of critical metabolites and (5) pathway rewiring. While this functional characterization underscores the evolvability potential of many essential genes, we also show that genes with differential essentiality remain important antimicrobial drug target candidates, as their inactivation almost always has a severe fitness cost in vivo.
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Affiliation(s)
| | - Emily Rudmann
- Biology Department, Boston College, Chestnut Hill, MA, USA
| | - Jien Li
- Biology Department, Boston College, Chestnut Hill, MA, USA
| | - Defne Surujon
- Biology Department, Boston College, Chestnut Hill, MA, USA
| | - Jon Anthony
- Biology Department, Boston College, Chestnut Hill, MA, USA
| | - Matthew Frank
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Dakota S Jones
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Charles Rock
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Jason W Rosch
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Christopher D Johnston
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Tim van Opijnen
- Biology Department, Boston College, Chestnut Hill, MA, USA.
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
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Lamanna MM, Manzoor I, Joseph M, Ye ZA, Benedet M, Zanardi A, Ren Z, Wang X, Massidda O, Tsui HT, Winkler ME. Roles of RodZ and class A PBP1b in the assembly and regulation of the peripheral peptidoglycan elongasome in ovoid-shaped cells of Streptococcus pneumoniae D39. Mol Microbiol 2022; 118:336-368. [PMID: 36001060 PMCID: PMC9804626 DOI: 10.1111/mmi.14969] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/30/2022] [Accepted: 08/02/2022] [Indexed: 01/17/2023]
Abstract
RodZ of rod-shaped bacteria functions to link MreB filaments to the Rod peptidoglycan (PG) synthase complex that moves circumferentially perpendicular to the long cell axis, creating hoop-like sidewall PG. Ovoid-shaped bacteria, such as Streptococcus pneumoniae (pneumococcus; Spn) that lack MreB, use a different modality for peripheral PG elongation that emanates from the midcell of dividing cells. Yet, S. pneumoniae encodes a RodZ homolog similar to RodZ in rod-shaped bacteria. We show here that the helix-turn-helix and transmembrane domains of RodZ(Spn) are essential for growth at 37°C. ΔrodZ mutations are suppressed by Δpbp1a, mpgA(Y488D), and ΔkhpA mutations that suppress ΔmreC, but not ΔcozE. Consistent with a role in PG elongation, RodZ(Spn) co-localizes with MreC and aPBP1a throughout the cell cycle and forms complexes and interacts with PG elongasome proteins and regulators. Depletion of RodZ(Spn) results in aberrantly shaped, non-growing cells and mislocalization of elongasome proteins MreC, PBP2b, and RodA. Moreover, Tn-seq reveals that RodZ(Spn), but not MreCD(Spn), displays a specific synthetic-viable genetic relationship with aPBP1b, whose function is unknown. We conclude that RodZ(Spn) acts as a scaffolding protein required for elongasome assembly and function and that aPBP1b, like aPBP1a, plays a role in elongasome regulation and possibly peripheral PG synthesis.
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Affiliation(s)
- Melissa M. Lamanna
- Department of BiologyIndiana University BloomingtonBloomingtonIndianaUSA
| | - Irfan Manzoor
- Department of BiologyIndiana University BloomingtonBloomingtonIndianaUSA
| | - Merrin Joseph
- Department of BiologyIndiana University BloomingtonBloomingtonIndianaUSA
| | - Ziyun A. Ye
- Department of BiologyIndiana University BloomingtonBloomingtonIndianaUSA
| | - Mattia Benedet
- Department of Cellular, Computational and Integrative Biology (CIBIO)University of TrentoTrentoItaly
| | - Alessia Zanardi
- Department of Cellular, Computational and Integrative Biology (CIBIO)University of TrentoTrentoItaly
| | - Zhongqing Ren
- Department of BiologyIndiana University BloomingtonBloomingtonIndianaUSA
| | - Xindan Wang
- Department of BiologyIndiana University BloomingtonBloomingtonIndianaUSA
| | - Orietta Massidda
- Department of Cellular, Computational and Integrative Biology (CIBIO)University of TrentoTrentoItaly
| | - Ho‐Ching T. Tsui
- Department of BiologyIndiana University BloomingtonBloomingtonIndianaUSA
| | - Malcolm E. Winkler
- Department of BiologyIndiana University BloomingtonBloomingtonIndianaUSA
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Tarika JDD, Dexlin XDD, Rathika A, Arun kumar A, Jayanthi DD, Beaula TJ. Impact of Protonation and Hydrogen Bonding Interactions on the Biological Properties of Antibacterial Compound 4-Dimethylaminopyridinium Salicylate Monohydrate: Correlation with Its Precursor Molecules. Polycycl Aromat Compd 2022. [DOI: 10.1080/10406638.2022.2110904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Affiliation(s)
- J. D. Deephlin Tarika
- Department of Physics and Research Centre, Malankara Catholic College, Mariagiri, India
| | - X. D. Divya Dexlin
- Department of Physics and Research Centre, Malankara Catholic College, Mariagiri, India
| | - A. Rathika
- Department of Physics and Research Centre, Muslim Arts College, Tiruvithancode, India
| | - A. Arun kumar
- Department of Physics (H&Sc), Methodist College of Engineering and Technology (Autonomous), Hyderabad, India
| | - D. Deva Jayanthi
- Department of Physics and Research Centre, Rani Anna Government College for Women, Tirunelveli, India
| | - T. Joselin Beaula
- Department of Physics and Research Centre, Malankara Catholic College, Mariagiri, India
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45
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A newly identified flavoprotein disulfide reductase Har protects Streptococcus pneumoniae against hypothiocyanous acid. J Biol Chem 2022; 298:102359. [PMID: 35952759 PMCID: PMC9483559 DOI: 10.1016/j.jbc.2022.102359] [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: 07/01/2022] [Revised: 08/04/2022] [Accepted: 08/05/2022] [Indexed: 11/25/2022] Open
Abstract
Hypothiocyanous acid (HOSCN) is an antimicrobial oxidant produced from hydrogen peroxide and thiocyanate anions by heme peroxidases in secretory fluids such as in the human respiratory tract. Some respiratory tract pathogens display tolerance to this oxidant, which suggests that there might be therapeutic value in targeting HOSCN defense mechanisms. However, surprisingly little is known about how bacteria protect themselves from HOSCN. We hypothesized that tolerant pathogens have a flavoprotein disulfide reductase that uses NAD(P)H to directly reduce HOSCN, similar to thioredoxin reductase in mammalian cells. Here, we report the discovery of a previously uncharacterized flavoprotein disulfide reductase with HOSCN reductase activity, which we term Har (hypothiocyanous acid reductase), in Streptococcus pneumoniae, a bacterium previously found to be tolerant of HOSCN. S. pneumoniae generates large amounts of hydrogen peroxide that can be converted to HOSCN in the respiratory tract. Using deletion mutants, we demonstrate that the HOSCN reductase is dispensable for growth of S. pneumoniae in the presence of lactoperoxidase and thiocyanate. However, bacterial growth in the HOSCN-generating system was completely crippled when deletion of HOSCN reductase activity was combined with disruption of GSH import or recycling. Our findings identify a new bacterial HOSCN reductase and demonstrate a role for this protein in combination with GSH utilization to protect S. pneumoniae from HOSCN.
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46
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Induction of the macrolide-resistance efflux pump Mega inhibits intoxication of Staphylococcus aureus strains by Streptococcus pneumoniae. Microbiol Res 2022; 263:127134. [PMID: 35905580 DOI: 10.1016/j.micres.2022.127134] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 07/06/2022] [Accepted: 07/13/2022] [Indexed: 11/21/2022]
Abstract
Streptococcus pneumoniae (Spn) kills Staphylococcus aureus (Sau) through a contact-dependent mechanism that is catalyzed by cations, including iron, to convert hydrogen peroxide (H2O2) to highly toxic hydroxyl radicals (•OH). There are two well-characterized ABC transporters that contribute to the pool of iron in Spn, named Pia and Piu. Some Spn strains have acquired genes mef(E)/mel encoding another ABC trasporter (Mega) that produces an inducible efflux pump for resistance to macrolides. In macrolide-resistant Spn clinical isolates the insertion of Mega class 1. IV and 2. IVc deleted the locus piaABCD and these strains were attenuated for intoxicating Sau. The goal of this study was to investigate if the disruption of iron acquisition, or the antimicrobial-resistance activity of Mega, contributed to inhibiting the killing mechanism. Neither depletion of iron with 2,2'-dipyridyl-d8 (DP) nor incubating with a double knockout mutant SpnΔpiaAΔpiuA, inhibited killing of Sau. Clinical Spn strains carrying Mega1. IV or Mega2. IVc showed a significant delay for killing Sau. An ex vivo recombination system was used to transfer Mega1. IV or Mega2. IVc to reference Spn strains, which was confirmed by whole genome sequencing, and recombinants TIGR4Mega2. IVc, D39Mega2. IVc, and D39Mega1. IV were delayed for killing Sau. We then compared Sau killing of selected Mega-carrying Spn strains when incubated with sub-inhibitory erythromycin (Mega-induced) or sub-inhibitory cefuroxime. Remarkably, killing of Sau was completely inhibited under the Mega-induced condition whereas incubation with cefuroxime did not interfere with killing. Both mef(E) and mel were upregulated > 400-fold, and spxB (encoding an enzyme responsible for production of most H2O2) was upregulated 14.2-fold, whereas transcription of the autolysin (lytA) gene was downregulated when incubated with erythromycin. We demonstrated that erythromycin induction of Mega inhibits the •OH-mediated intoxication of Sau and that the inhibition occurred at the post-translational level suggesting that an imbalance of ions in the membrane inhibits these reactions.
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47
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Hames RG, Jasiunaite Z, Ercoli G, Wanford JJ, Carreno D, Straatman K, Martinez-Pomares L, Yesilkaya H, Glenn S, Moxon ER, Andrew PW, Kyriacou CP, Oggioni MR. Diurnal Differences in Intracellular Replication Within Splenic Macrophages Correlates With the Outcome of Pneumococcal Infection. Front Immunol 2022; 13:907461. [PMID: 35720383 PMCID: PMC9201068 DOI: 10.3389/fimmu.2022.907461] [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: 03/29/2022] [Accepted: 05/09/2022] [Indexed: 12/04/2022] Open
Abstract
Circadian rhythms affect the progression and severity of bacterial infections including those caused by Streptococcus pneumoniae, but the mechanisms responsible for this phenomenon remain largely elusive. Following advances in our understanding of the role of replication of S. pneumoniae within splenic macrophages, we sought to investigate whether events within the spleen correlate with differential outcomes of invasive pneumococcal infection. Utilising murine invasive pneumococcal disease (IPD) models, here we report that infection during the murine active phase (zeitgeber time 15; 15h after start of light cycle, 3h after start of dark cycle) resulted in significantly faster onset of septicaemia compared to rest phase (zeitgeber time 3; 3h after start of light cycle) infection. This correlated with significantly higher pneumococcal burden within the spleen of active phase-infected mice at early time points compared to rest phase-infected mice. Whole-section confocal microscopy analysis of these spleens revealed that the number of pneumococci is significantly higher exclusively within marginal zone metallophilic macrophages (MMMs) known to allow intracellular pneumococcal replication as a prerequisite step to the onset of septicaemia. Pneumococcal clusters within MMMs were more abundant and increased in size over time in active phase-infected mice compared to those in rest phase-infected mice which decreased in size and were present in a lower percentage of MMMs. This phenomenon preceded significantly higher levels of bacteraemia alongside serum IL-6 and TNF-α concentrations in active phase-infected mice following re-seeding of pneumococci into the blood. These data greatly advance our fundamental knowledge of pneumococcal infection by linking susceptibility to invasive pneumococcal infection to variation in the propensity of MMMs to allow persistence and replication of phagocytosed bacteria. These findings also outline a somewhat rare scenario whereby the active phase of an organism’s circadian cycle plays a seemingly counterproductive role in the control of invasive infection.
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Affiliation(s)
- Ryan G Hames
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | - Zydrune Jasiunaite
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | - Giuseppe Ercoli
- Centre for Inflammation and Tissue Repair, UCL Respiratory, Division of Medicine, University College Medical School, London, United Kingdom
| | - Joseph J Wanford
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | - David Carreno
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | - Kornelis Straatman
- Advanced Imaging Facility, University of Leicester, Leicester, United Kingdom
| | | | - Hasan Yesilkaya
- Department of Respiratory Sciences, University of Leicester, Leicester, United Kingdom
| | - Sarah Glenn
- Preclinical Research Facility, University of Leicester, Leicester, United Kingdom
| | - E Richard Moxon
- Department of Paediatrics, University of Oxford, Oxford, United Kingdom
| | - Peter W Andrew
- Department of Respiratory Sciences, University of Leicester, Leicester, United Kingdom
| | - Charalambos P Kyriacou
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | - Marco R Oggioni
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom.,Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
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48
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Phagosomal Acidification Is Required to Kill Streptococcus pneumoniae in a Zebrafish Model. Cell Microbiol 2022. [DOI: 10.1155/2022/9429516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Streptococcus pneumoniae (the pneumococcus) is a major human pathogen causing invasive disease, including community-acquired bacteraemia, and remains a leading cause of global mortality. Understanding the role of phagocytes in killing bacteria is still limited, especially in vivo. In this study, we established a zebrafish model to study the interaction between intravenously administered pneumococci and professional phagocytes such as macrophages and neutrophils, to unravel bacterial killing mechanisms employed by these immune cells. Our model confirmed the key role of polysaccharide capsule in promoting pneumococcal virulence through inhibition of phagocytosis. Conversely, we show pneumococci lacking a capsule are rapidly internalised by macrophages. Low doses of encapsulated S. pneumoniae cause near 100% mortality within 48 hours postinfection (hpi), while 50 times higher doses of unencapsulated pneumococci are easily cleared. Time course analysis of in vivo bacterial numbers reveals that while encapsulated pneumococcus proliferates to levels exceeding 105 CFU at the time of host death, unencapsulated bacteria are unable to grow and are cleared within 20 hpi. Using genetically induced macrophage depletion, we confirmed an essential role for macrophages in bacterial clearance. Additionally, we show that upon phagocytosis by macrophages, phagosomes undergo rapid acidification. Genetic and chemical inhibition of vacuolar ATPase (v-ATPase) prevents intracellular bacterial killing and induces host death indicating a key role of phagosomal acidification in immunity to invading pneumococci. We also show that our model can be used to study the efficacy of antimicrobials against pneumococci in vivo. Collectively, our data confirm that larval zebrafish can be used to dissect killing mechanisms during pneumococcal infection in vivo and highlight key roles for phagosomal acidification in macrophages for pathogen clearance.
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49
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Flores-Kim J, Dobihal GS, Bernhardt TG, Rudner DZ. WhyD tailors surface polymers to prevent premature bacteriolysis and direct cell elongation in Streptococcus pneumoniae. eLife 2022; 11:e76392. [PMID: 35593695 PMCID: PMC9208761 DOI: 10.7554/elife.76392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 05/19/2022] [Indexed: 11/30/2022] Open
Abstract
Penicillin and related antibiotics disrupt cell wall synthesis in bacteria causing the downstream misactivation of cell wall hydrolases called autolysins to induce cell lysis. Despite the clinical importance of this phenomenon, little is known about the factors that control autolysins and how penicillins subvert this regulation to kill cells. In the pathogen Streptococcus pneumoniae (Sp), LytA is the major autolysin responsible for penicillin-induced bacteriolysis. We recently discovered that penicillin treatment of Sp causes a dramatic shift in surface polymer biogenesis in which cell wall-anchored teichoic acids (WTAs) increase in abundance at the expense of lipid-linked teichoic acids (LTAs). Because LytA binds to both species of teichoic acids, this change recruits the enzyme to its substrate where it cleaves the cell wall and elicits lysis. In this report, we identify WhyD (SPD_0880) as a new factor that controls the level of WTAs in Sp cells to prevent LytA misactivation and lysis during exponential growth . We show that WhyD is a WTA hydrolase that restricts the WTA content of the wall to areas adjacent to active peptidoglycan (PG) synthesis. Our results support a model in which the WTA tailoring activity of WhyD during exponential growth directs PG remodeling activity required for proper cell elongation in addition to preventing autolysis by LytA.
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Affiliation(s)
- Josué Flores-Kim
- Department of Microbiology, Harvard Medical SchoolBostonUnited States
- UMass Chan Medical SchoolWorcesterUnited States
| | | | - Thomas G Bernhardt
- Department of Microbiology, Harvard Medical SchoolBostonUnited States
- Howard Hughes Medical InstituteBostonUnited States
| | - David Z Rudner
- Department of Microbiology, Harvard Medical SchoolBostonUnited States
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50
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Zhang Y, Martin JE, Edmonds KA, Winkler ME, Giedroc DP. SifR is an Rrf2-family quinone sensor associated with catechol iron uptake in Streptococcus pneumoniae D39. J Biol Chem 2022; 298:102046. [PMID: 35597283 PMCID: PMC9218516 DOI: 10.1016/j.jbc.2022.102046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/29/2022] [Accepted: 05/03/2022] [Indexed: 01/15/2023] Open
Abstract
Streptococcus pneumoniae (pneumococcus) is a Gram-positive commensal and human respiratory pathogen. How this bacterium satisfies its nutritional iron (Fe) requirement in the context of endogenously produced hydrogen peroxide is not well understood. Here, we characterize a novel virulence-associated Rrf2-family transcriptional repressor that we term SifR (streptococcal IscR-like family transcriptional repressor) encoded by spd_1448 and conserved in Streptococci. Global transcriptomic analysis of a ΔsifR strain defines the SifR regulon as genes encoding a candidate catechol dioxygenase CatE, an uncharacterized oxidoreductase YwnB, a candidate flavin-dependent ferric reductase YhdA, a candidate heme-based ferric reductase domain-containing protein and the Piu (pneumococcus iron uptake) Fe transporter (piuBCDA). Previous work established that membrane-anchored PiuA binds FeIII-bis-catechol or monocatechol complexes with high affinity, including the human catecholamine stress hormone, norepinephrine. We demonstrate that SifR senses quinone via a single conserved cysteine that represses its regulon when in the reduced form. Upon reaction with catechol-derived quinones, we show that SifR dissociates from the DNA leading to regulon derepression, allowing the pneumococcus to access a catechol-derived source of Fe while minimizing reactive electrophile stress induced by quinones. Consistent with this model, we show that CatE is an FeII-dependent 2,3-catechol dioxygenase with broad substrate specificity, YwnB is an NAD(P)H-dependent quinone reductase capable of reducing the oxidized and cyclized norepinephrine, adrenochrome, and YhdA is capable of reducing a number of FeIII complexes, including PiuA-binding transport substrates. These findings are consistent with a model where FeIII-catechol complexes serve as significant nutritional Fe sources in the host.
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Affiliation(s)
- Yifan Zhang
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA; Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana, USA
| | - Julia E Martin
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA; Department of Biological Sciences, Idaho State University, Pocatello, Idaho, USA
| | | | - Malcolm E Winkler
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana, USA; Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA; Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana, USA.
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