1
|
Cinar MS, Niyas A, Avci FY. Serine-rich repeat proteins: well-known yet little-understood bacterial adhesins. J Bacteriol 2024; 206:e0024123. [PMID: 37975670 PMCID: PMC10810200 DOI: 10.1128/jb.00241-23] [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] [Indexed: 11/19/2023] Open
Abstract
Serine-rich-repeat proteins (SRRPs) are large mucin-like glycoprotein adhesins expressed by a plethora of pathogenic and symbiotic Gram-positive bacteria. SRRPs play major functional roles in bacterial-host interactions, like adhesion, aggregation, biofilm formation, virulence, and pathogenesis. Through their functional roles, SRRPs aid in the development of host microbiomes but also diseases like infective endocarditis, otitis media, meningitis, and pneumonia. SRRPs comprise shared domains across different species, including two or more heavily O-glycosylated long stretches of serine-rich repeat regions. With loci that can be as large as ~40 kb and can encode up to 10 distinct glycosyltransferases that specifically facilitate SRRP glycosylation, the SRRP loci makes up a significant portion of the bacterial genome. The significance of SRRPs and their glycans in host-microbe communications is becoming increasingly evident. Studies are beginning to reveal the glycosylation pathways and mature O-glycans presented by SRRPs. Here we review the glycosylation machinery of SRRPs across species and discuss the functional roles and clinical manifestations of SRRP glycosylation.
Collapse
Affiliation(s)
- Mukaddes S. Cinar
- Department of Biochemistry, Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Afaq Niyas
- Department of Biochemistry, Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Fikri Y. Avci
- Department of Biochemistry, Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia, USA
| |
Collapse
|
2
|
Aceil J, Venkat A, Pan E, Kannan N, Avci FY. Prevalence and Homology of the Pneumococcal Serine-Rich Repeat Protein at the Global Scale. Microbiol Spectr 2023; 11:e0325222. [PMID: 36995217 PMCID: PMC10269691 DOI: 10.1128/spectrum.03252-22] [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: 08/17/2022] [Accepted: 03/09/2023] [Indexed: 03/31/2023] Open
Abstract
Pneumococcal pneumonia remains a WHO high-priority disease despite multivalent conjugate vaccines administered in clinical practice worldwide. A protein-based, serotype-independent vaccine has long-promised comprehensive coverage of most clinical isolates of the pneumococcus. Along with numerous pneumococcal surface protein immunogens, the pneumococcal serine-rich repeat protein (PsrP) has been investigated as a potential vaccine target due to its surface exposure and functions toward bacterial virulence and lung infection. Three critical criteria for its vaccine potential - the clinical prevalence, serotype distribution, and sequence homology of PsrP - have yet to be well characterized. Here, we used genomes of 13,454 clinically isolated pneumococci from the Global Pneumococcal Sequencing project to investigate PsrP presence among isolates, distribution among serotypes, and interrogate its homology as a protein across species. These isolates represent all age groups, countries worldwide, and types of pneumococcal infection. We found PsrP present in at least 50% of all isolates across all determined serotypes and nontypeable (NT) clinical isolates. Using a combination of peptide matching and HMM profiles built on full-length and individual PsrP domains, we identified novel variants that expand PsrP diversity and prevalence. We also observed sequence variability in its basic region (BR) between isolates and serotypes. PsrP has a strong vaccine potential due to its breadth of coverage, especially in nonvaccine serotypes (NVTs) when exploiting its regions of conservation in vaccine design. IMPORTANCE An updated outlook on PsrP prevalence and serotype distribution sheds new light on the comprehensiveness of a PsrP-based protein vaccine. The protein is present in all vaccine serotypes and highly present in the next wave of potentially disease-causing serotypes not included in the current multivalent conjugate vaccines. Furthermore, PsrP is strongly correlated with clinical isolates harboring pneumococcal disease as opposed to pneumococcal carriage. PsrP is also highly present in strains and serotypes from Africa, where the need for a protein-based vaccine is the greatest, giving new reasoning to pursue PsrP as a protein vaccine.
Collapse
Affiliation(s)
- Javid Aceil
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Aarya Venkat
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Eric Pan
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Natarajan Kannan
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Fikri Y. Avci
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
- Department of Biochemistry, Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia, USA
| |
Collapse
|
3
|
Wang L, Wang H, Zhang H, Wu H. Formation of a biofilm matrix network shapes polymicrobial interactions. THE ISME JOURNAL 2023; 17:467-477. [PMID: 36639539 PMCID: PMC9938193 DOI: 10.1038/s41396-023-01362-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 12/30/2022] [Accepted: 01/09/2023] [Indexed: 01/15/2023]
Abstract
Staphylococcus aureus colonizes the same ecological niche as many commensals. However, little is known about how such commensals modulate staphylococcal fitness and persistence. Here we report a new mechanism that mediates dynamic interactions between a commensal streptococcus and S. aureus. Commensal Streptococcus parasanguinis significantly increased the staphylococcal biofilm formation in vitro and enhanced its colonization in vivo. A streptococcal biofilm-associated protein BapA1, not fimbriae-associated protein Fap1, is essential for dual-species biofilm formation. On the other side, three staphylococcal virulence determinants responsible for the BapA1-dependent dual-species biofilm formation were identified by screening a staphylococcal transposon mutant library. The corresponding staphylococcal mutants lacked binding to recombinant BapA1 (rBapA1) due to lower amounts of eDNA in their culture supernatants and were defective in biofilm formation with streptococcus. The rBapA1 selectively colocalized with eDNA within the dual-species biofilm and bound to eDNA in vitro, highlighting the contributions of the biofilm matrix formed between streptococcal BapA1 and staphylococcal eDNA to dual-species biofilm formation. These findings have revealed an additional new mechanism through which an interspecies biofilm matrix network mediates polymicrobial interactions.
Collapse
Affiliation(s)
- Lijun Wang
- Departments of Pediatric Dentistry and Microbiology, University of Alabama at Birmingham Schools of Dentistry and Medicine, Birmingham, Alabama, 35294, USA
- Department of Laboratory Medicine, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, 102218, Beijing, China
| | - Hongxia Wang
- Departments of Pediatric Dentistry and Microbiology, University of Alabama at Birmingham Schools of Dentistry and Medicine, Birmingham, Alabama, 35294, USA
| | - Hua Zhang
- Departments of Pediatric Dentistry and Microbiology, University of Alabama at Birmingham Schools of Dentistry and Medicine, Birmingham, Alabama, 35294, USA
- Department of Integrative Biomedical and Diagnostic Sciences, Oregon Health and Science University School of Dentistry, Portland, OR, 97239, USA
| | - Hui Wu
- Departments of Pediatric Dentistry and Microbiology, University of Alabama at Birmingham Schools of Dentistry and Medicine, Birmingham, Alabama, 35294, USA.
- Department of Integrative Biomedical and Diagnostic Sciences, Oregon Health and Science University School of Dentistry, Portland, OR, 97239, USA.
| |
Collapse
|
4
|
Aceil J, Avci FY. Pneumococcal Surface Proteins as Virulence Factors, Immunogens, and Conserved Vaccine Targets. Front Cell Infect Microbiol 2022; 12:832254. [PMID: 35646747 PMCID: PMC9133333 DOI: 10.3389/fcimb.2022.832254] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 04/13/2022] [Indexed: 11/13/2022] Open
Abstract
Streptococcus pneumoniae is an opportunistic pathogen that causes over 1 million deaths annually despite the availability of several multivalent pneumococcal conjugate vaccines (PCVs). Due to the limitations surrounding PCVs along with an evolutionary rise in antibiotic-resistant and unencapsulated strains, conserved immunogenic proteins as vaccine targets continue to be an important field of study for pneumococcal disease prevention. In this review, we provide an overview of multiple classes of conserved surface proteins that have been studied for their contribution to pneumococcal virulence. Furthermore, we discuss the immune responses observed in response to these proteins and their promise as vaccine targets.
Collapse
|
5
|
Extracellular DNA (eDNA). A Major Ubiquitous Element of the Bacterial Biofilm Architecture. Int J Mol Sci 2021; 22:ijms22169100. [PMID: 34445806 PMCID: PMC8396552 DOI: 10.3390/ijms22169100] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 12/22/2022] Open
Abstract
After the first ancient studies on microbial slime (the name by which the biofilm matrix was initially indicated), multitudes of studies on the morphology, composition and physiology of biofilms have arisen. The emergence of the role that biofilms play in the pathogenesis of recalcitrant and persistent clinical infections, such as periprosthetic orthopedic infections, has reinforced scientific interest. Extracellular DNA (eDNA) is a recently uncovered component that is proving to be almost omnipresent in the extracellular polymeric substance (EPS) of biofilm. This macromolecule is eliciting unprecedented consideration for the critical impact on the pathogenesis of chronic clinical infections. After a systematic review of the literature, an updated description of eDNA in biofilms is presented, with a special focus on the latest findings regarding its fundamental structural role and the contribution it makes to the complex architecture of bacterial biofilms through interactions with a variety of other molecular components of the biofilm matrix.
Collapse
|
6
|
Abdel‐Aziz MI, Kermani NZ, Neerincx AH, Vijverberg SJH, Guo Y, Howarth P, Dahlen S, Djukanovic R, Sterk PJ, Kraneveld AD, Maitland‐van der Zee AH, Chung KF, Adcock IM. Association of endopeptidases, involved in SARS-CoV-2 infection, with microbial aggravation in sputum of severe asthma. Allergy 2021; 76:1917-1921. [PMID: 33411967 DOI: 10.1111/all.14731] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 12/21/2020] [Accepted: 01/01/2021] [Indexed: 01/06/2023]
Affiliation(s)
- Mahmoud I. Abdel‐Aziz
- Department of Respiratory Medicine Amsterdam UMCUniversity of Amsterdam Amsterdam The Netherlands
- Department of Clinical Pharmacy Faculty of Pharmacy Assiut University Assiut Egypt
| | | | - Anne H. Neerincx
- Department of Respiratory Medicine Amsterdam UMCUniversity of Amsterdam Amsterdam The Netherlands
| | - Susanne J. H. Vijverberg
- Department of Respiratory Medicine Amsterdam UMCUniversity of Amsterdam Amsterdam The Netherlands
| | - Yike Guo
- Data Science Institute Imperial College London London UK
| | - Peter Howarth
- NIHR Southampton Respiratory Biomedical Research Unit, Clinical and Experimental Sciences and Human Development and Health University of Southampton Southampton UK
| | - Sven‐Erik Dahlen
- Centre for Allergy Research Institute of Environmental Medicine Karolinska Institutet Stockholm Sweden
| | - Ratko Djukanovic
- NIHR Southampton Respiratory Biomedical Research Unit, Clinical and Experimental Sciences and Human Development and Health University of Southampton Southampton UK
| | - Peter J. Sterk
- Department of Respiratory Medicine Amsterdam UMCUniversity of Amsterdam Amsterdam The Netherlands
| | - Aletta D. Kraneveld
- Division of Pharmacology Faculty of Science Utrecht Institute for Pharmaceutical Sciences Utrecht University Utrecht The Netherlands
- Faculty of Veterinary Medicine Institute for Risk Assessment Sciences Utrecht University Utrecht The Netherlands
| | - Anke H. Maitland‐van der Zee
- Department of Respiratory Medicine Amsterdam UMCUniversity of Amsterdam Amsterdam The Netherlands
- Department of Pediatric Respiratory Medicine Emma Children's Hospital Amsterdam UMC Amsterdam The Netherlands
| | - Kian Fan Chung
- National Heart and Lung Institute Imperial College London, and Royal Brompton and Harefield NHS Trust London UK
| | - Ian M. Adcock
- National Heart and Lung Institute Imperial College London and the NIHR Imperial Biomedical Research Centre London UK
| | | |
Collapse
|
7
|
Chan JM, Gori A, Nobbs AH, Heyderman RS. Streptococcal Serine-Rich Repeat Proteins in Colonization and Disease. Front Microbiol 2020; 11:593356. [PMID: 33193266 PMCID: PMC7661464 DOI: 10.3389/fmicb.2020.593356] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 10/12/2020] [Indexed: 01/10/2023] Open
Abstract
Glycosylation of proteins, previously thought to be absent in prokaryotes, is increasingly recognized as important for both bacterial colonization and pathogenesis. For mucosal pathobionts, glycoproteins that function as cell wall-associated adhesins facilitate interactions with mucosal surfaces, permitting persistent adherence, invasion of deeper tissues and transition to disease. This is exemplified by Streptococcus pneumoniae and Streptococcus agalactiae, which can switch from being relatively harmless members of the mucosal tract microbiota to bona fide pathogens that cause life-threatening diseases. As part of their armamentarium of virulence factors, streptococci encode a family of large, glycosylated serine-rich repeat proteins (SRRPs) that facilitate binding to various tissue types and extracellular matrix proteins. This minireview focuses on the roles of S. pneumoniae and S. agalactiae SRRPs in persistent colonization and the transition to disease. The potential of utilizing SRRPs as vaccine targets will also be discussed.
Collapse
Affiliation(s)
- Jia Mun Chan
- NIHR Mucosal Pathogens Research Unit, Division of Infection and Immunity, University College London, London, United Kingdom
| | - Andrea Gori
- NIHR Mucosal Pathogens Research Unit, Division of Infection and Immunity, University College London, London, United Kingdom
| | - Angela H. Nobbs
- Bristol Dental School, University of Bristol, Bristol, United Kingdom
| | - Robert S. Heyderman
- NIHR Mucosal Pathogens Research Unit, Division of Infection and Immunity, University College London, London, United Kingdom
| |
Collapse
|
8
|
Schulte T, Sala BM, Nilvebrant J, Nygren PÅ, Achour A, Shernyukov A, Agback T, Agback P. Assigned NMR backbone resonances of the ligand-binding region domain of the pneumococcal serine-rich repeat protein (PsrP-BR) reveal a rigid monomer in solution. BIOMOLECULAR NMR ASSIGNMENTS 2020; 14:195-200. [PMID: 32314099 PMCID: PMC7462905 DOI: 10.1007/s12104-020-09944-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/08/2020] [Indexed: 06/11/2023]
Abstract
The pneumococcal serine rich repeat protein (PsrP) is displayed on the surface of Streptococcus pneumoniae with a suggested role in colonization in the human upper respiratory tract. Full-length PsrP is a 4000 residue-long multi-domain protein comprising a positively charged functional binding region (BR) domain for interaction with keratin and extracellular DNA during pneumococcal adhesion and biofilm formation, respectively. The previously determined crystal structure of the BR domain revealed a flat compressed barrel comprising two sides with an extended β-sheet on one side, and another β-sheet that is distorted by loops and β-turns on the other side. Crystallographic B-factors indicated a relatively high mobility of loop regions that were hypothesized to be important for binding. Furthermore, the crystal structure revealed an inter-molecular β-sheet formed between edge strands of two symmetry-related molecules, which could promote bacterial aggregation during biofilm formation. Here we report the near complete 15N/13C/1H backbone resonance assignment of the BR domain of PsrP, revealing a secondary structure profile that is almost identical to the X-ray structure. Dynamic 15N-T1, T2 and NOE data suggest a monomeric and rigid structure of BR with disordered residues only at the N- and C-termini. The presented peak assignment will allow us to identify BR residues that are crucial for ligand binding.
Collapse
Affiliation(s)
- Tim Schulte
- Science for Life Laboratory, Department of Medicine, Solna, Karolinska Institute, and Division of Infectious Diseases, Karolinska University Hospital, SE-171 76, Stockholm, Sweden
| | - Benedetta Maria Sala
- Science for Life Laboratory, Department of Medicine, Solna, Karolinska Institute, and Division of Infectious Diseases, Karolinska University Hospital, SE-171 76, Stockholm, Sweden
- Division of Protein Engineering, Department of Protein Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, AlbaNova University Center, Royal Institute of Technology, and Science for Life Laboratory, SE-100 44, Stockholm, Sweden
| | - Johan Nilvebrant
- Division of Protein Engineering, Department of Protein Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, AlbaNova University Center, Royal Institute of Technology, and Science for Life Laboratory, SE-100 44, Stockholm, Sweden
| | - Per-Åke Nygren
- Division of Protein Engineering, Department of Protein Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, AlbaNova University Center, Royal Institute of Technology, and Science for Life Laboratory, SE-100 44, Stockholm, Sweden
| | - Adnane Achour
- Science for Life Laboratory, Department of Medicine, Solna, Karolinska Institute, and Division of Infectious Diseases, Karolinska University Hospital, SE-171 76, Stockholm, Sweden
| | - Andrey Shernyukov
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, PO Box 7015, 750 07, Uppsala, Sweden
- Laboratory of Magnetic Radiospectroscopy, N.N. Vorozhtsov Institute of Organic Chemistry, SB RAS, Lavrentiev ave. 9, Novosibirsk, Russia, 630090
| | - Tatiana Agback
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, PO Box 7015, 750 07, Uppsala, Sweden
| | - Peter Agback
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, PO Box 7015, 750 07, Uppsala, Sweden.
| |
Collapse
|
9
|
Domenech M, García E. The N-Acetylglucosaminidase LytB of Streptococcus pneumoniae Is Involved in the Structure and Formation of Biofilms. Appl Environ Microbiol 2020; 86:e00280-20. [PMID: 32198170 PMCID: PMC7205503 DOI: 10.1128/aem.00280-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 03/15/2020] [Indexed: 02/07/2023] Open
Abstract
The N-acetylglucosaminidase LytB of Streptococcus pneumoniae is involved in nasopharyngeal colonization and is responsible for cell separation at the end of cell division; thus, ΔlytB mutants form long chains of cells. This paper reports the construction and properties of a defective pneumococcal mutant producing an inactive LytB protein (LytBE585A). It is shown that an enzymatically active LytB is required for in vitro biofilm formation, as lytB mutants (either ΔlytB or producing the inactive LytBE585A) are incapable of forming substantial biofilms, despite that extracellular DNA is present in the biofilm matrix. Adding small amounts (0.5 to 2.0 μg/ml) of exogenous LytB or some LytB constructs restored the biofilm-forming capacity of lytB mutants to wild-type levels. The LytBE585A mutant formed biofilm more rapidly than ΔlytB mutants in the presence of LytB. This suggests that the mutant protein acted in a structural role, likely through the formation of complexes with extracellular DNA. The chain-dispersing capacity of LytB allowed the separation of daughter cells, presumably facilitating the formation of microcolonies and, finally, of biofilms. A role for the possible involvement of LytB in the synthesis of the extracellular polysaccharide component of the biofilm matrix is also discussed.IMPORTANCE It has been previously accepted that biofilm formation in S. pneumoniae must be a multigenic trait because the mutation of a single gene has led to only to partial inhibition of biofilm production. In the present study, however, evidence that the N-acetylglucosaminidase LytB is crucial in biofilm formation is provided. Despite the presence of extracellular DNA, strains either deficient in LytB or producing a defective LytB enzyme formed only shallow biofilms.
Collapse
Affiliation(s)
- Mirian Domenech
- Departamento de Biotecnología Microbiana y de Plantas, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Ernesto García
- Departamento de Biotecnología Microbiana y de Plantas, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| |
Collapse
|
10
|
Guo C, Feng Z, Zuo G, Jiang YL, Zhou CZ, Chen Y, Hou WT. Structural and functional insights into the Asp1/2/3 complex mediated secretion of pneumococcal serine-rich repeat protein PsrP. Biochem Biophys Res Commun 2020; 524:784-790. [PMID: 32037091 DOI: 10.1016/j.bbrc.2020.01.146] [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: 01/23/2020] [Accepted: 01/27/2020] [Indexed: 11/29/2022]
Abstract
The accessory sec system consisting of seven conserved components is commonly distributed among pathogenic Gram-positive bacteria for the secretion of serine-rich-repeat proteins (SRRPs). Asp1/2/3 protein complex in the system is responsible for both the O-acetylation of GlcNAc and delivering SRRPs to SecA2. However, the molecular mechanism of how Asp1/2/3 transport SRRPs remains unknown. Here, we report the complex structure of Asp1/2/3 from Streptococcus pneumoniae at 2.9 Å. Further functional assays indicated that Asp1/2/3 can stimulate the ATPase activity of SecA2. In addition, the deletion of asp1/2/3 gene resulted in the accumulation of a secreted version of PsrP with an altered glycoform in protoplast fraction of the mutant cell, which suggested the modification/transport coupling of the substrate. Altogether, these findings not only provide structural basis for further investigations on the transport process of SRRPs, but also uncover the indispensable role of Asp1/2/3 in the accessory sec system.
Collapse
Affiliation(s)
- Cong Guo
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Zhang Feng
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Gang Zuo
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Yong-Liang Jiang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Cong-Zhao Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Yuxing Chen
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, China.
| | - Wen-Tao Hou
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, China.
| |
Collapse
|
11
|
Opening the OPK Assay Gatekeeper: Harnessing Multi-Modal Protection by Pneumococcal Vaccines. Pathogens 2019; 8:pathogens8040203. [PMID: 31652741 PMCID: PMC6963391 DOI: 10.3390/pathogens8040203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 10/14/2019] [Accepted: 10/21/2019] [Indexed: 11/16/2022] Open
Abstract
Pneumococcal vaccine development is driven by the achievement of high activity in a single gatekeeper assay: the bacterial opsonophagocytic killing (OPK) assay. New evidence challenges the dogma that anti-capsular antibodies have only a single function that predicts success. The emerging concept of multi-modal protection presents an array of questions that are fundamental to adopting a new vaccine design process. If antibodies have hidden non-opsonic functions that are protective, should these be optimized for better vaccines? What would protein antigens add to protective activity? Are cellular immune functions additive to antibodies for success? Do different organs benefit from different modes of protection? Can vaccine activities beyond OPK protect the immunocompromised host? This commentary raises these issues at a time when capsule-only OPK assay-based vaccines are increasingly seen as a limiting strategy.
Collapse
|
12
|
Streptococcus oralis subsp. dentisani Produces Monolateral Serine-Rich Repeat Protein Fibrils, One of Which Contributes to Saliva Binding via Sialic Acid. Infect Immun 2019; 87:IAI.00406-19. [PMID: 31308084 DOI: 10.1128/iai.00406-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 07/08/2019] [Indexed: 12/27/2022] Open
Abstract
Our studies reveal that the oral colonizer and cause of infective endocarditis Streptococcus oralis subsp. dentisani displays a striking monolateral distribution of surface fibrils. Furthermore, our data suggest that these fibrils impact the structure of adherent bacterial chains. Mutagenesis studies indicate that these fibrils are dependent on three serine-rich repeat proteins (SRRPs), here named fibril-associated protein A (FapA), FapB, and FapC, and that each SRRP forms a different fibril with a distinct distribution. SRRPs are a family of bacterial adhesins that have diverse roles in adhesion and that can bind to different receptors through modular nonrepeat region domains. Amino acid sequence and predicted structural similarity searches using the nonrepeat regions suggested that FapA may contribute to interspecies interactions, that FapA and FapB may contribute to intraspecies interactions, and that FapC may contribute to sialic acid binding. We demonstrate that a fapC mutant was significantly reduced in binding to saliva. We confirmed a role for FapC in sialic acid binding by demonstrating that the parental strain was significantly reduced in adhesion upon addition of a recombinantly expressed, sialic acid-specific, carbohydrate binding module, while the fapC mutant was not reduced. However, mutation of a residue previously shown to be essential for sialic acid binding did not decrease bacterial adhesion, leaving the precise mechanism of FapC-mediated adhesion to sialic acid to be defined. We also demonstrate that the presence of any one of the SRRPs is sufficient for efficient biofilm formation. Similar structures were observed on all infective endocarditis isolates examined, suggesting that this distribution is a conserved feature of this S. oralis subspecies.
Collapse
|
13
|
Abstract
We developed a new approach that couples Southwestern blotting and mass spectrometry to discover proteins that bind extracellular DNA (eDNA) in bacterial biofilms. Using Staphylococcus aureus as a model pathogen, we identified proteins with known DNA-binding activity and uncovered a series of lipoproteins with previously unrecognized DNA-binding activity. We demonstrated that expression of these lipoproteins results in an eDNA-dependent biofilm enhancement. Additionally, we found that while deletion of lipoproteins had a minimal impact on biofilm accumulation, these lipoprotein mutations increased biofilm porosity, suggesting that lipoproteins and their associated interactions contribute to biofilm structure. For one of the lipoproteins, SaeP, we showed that the biofilm phenotype requires the lipoprotein to be anchored to the outside of the cellular membrane, and we further showed that increased SaeP expression correlates with more retention of high-molecular-weight DNA on the bacterial cell surface. SaeP is a known auxiliary protein of the SaeRS system, and we also demonstrated that the levels of SaeP correlate with nuclease production, which can further impact biofilm development. It has been reported that S. aureus biofilms are stabilized by positively charged cytoplasmic proteins that are released into the extracellular environment, where they make favorable electrostatic interactions with the negatively charged cell surface and eDNA. In this work we extend this electrostatic net model to include secreted eDNA-binding proteins and membrane-attached lipoproteins that can function as anchor points between eDNA in the biofilm matrix and the bacterial cell surface.IMPORTANCE Many bacteria are capable of forming biofilms encased in a matrix of self-produced extracellular polymeric substances (EPS) that protects them from chemotherapies and the host defenses. As a result of these inherent resistance mechanisms, bacterial biofilms are extremely difficult to eradicate and are associated with chronic wounds, orthopedic and surgical wound infections, and invasive infections, such as infective endocarditis and osteomyelitis. It is therefore important to understand the nature of the interactions between the bacterial cell surface and EPS that stabilize biofilms. Extracellular DNA (eDNA) has been recognized as an EPS constituent for many bacterial species and has been shown to be important in promoting biofilm formation. Using Staphylococcus aureus biofilms, we show that membrane-attached lipoproteins can interact with the eDNA in the biofilm matrix and promote biofilm formation, which suggests that lipoproteins are potential targets for novel therapies aimed at disrupting bacterial biofilms.
Collapse
|
14
|
Latousakis D, MacKenzie DA, Telatin A, Juge N. Serine-rich repeat proteins from gut microbes. Gut Microbes 2019; 11:102-117. [PMID: 31035824 PMCID: PMC6973325 DOI: 10.1080/19490976.2019.1602428] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 03/08/2019] [Accepted: 03/27/2019] [Indexed: 02/03/2023] Open
Abstract
Serine-rich repeat proteins (SRRPs) have emerged as an important group of cell surface adhesins found in a growing number of Gram-positive bacteria. Studies focused on SRRPs from streptococci and staphylococci demonstrated that these proteins are O-glycosylated on serine or threonine residues and exported via an accessory secretion (aSec) system. In pathogens, these adhesins contribute to disease pathogenesis and represent therapeutic targets. Recently, the non-canonical aSec system has been identified in the genomes of gut microbes and characterization of their associated SRRPs is beginning to unfold, showing their role in mediating attachment and biofilm formation. Here we provide an update of the occurrence, structure, and function of SRRPs across bacteria, with emphasis on the molecular and biochemical properties of SRRPs from gut symbionts, particularly Lactobacilli. These emerging studies underscore the range of ligands recognized by these adhesins and the importance of SRRP glycosylation in the interaction of gut microbes with the host.
Collapse
Affiliation(s)
- Dimitrios Latousakis
- The Gut Microbes and Health Institute Strategic Programme, Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
| | - Donald A. MacKenzie
- The Gut Microbes and Health Institute Strategic Programme, Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
| | - Andrea Telatin
- The Gut Microbes and Health Institute Strategic Programme, Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
| | - Nathalie Juge
- The Gut Microbes and Health Institute Strategic Programme, Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
| |
Collapse
|
15
|
SssP1, a Streptococcus suis Fimbria-Like Protein Transported by the SecY2/A2 System, Contributes to Bacterial Virulence. Appl Environ Microbiol 2018; 84:AEM.01385-18. [PMID: 30030221 DOI: 10.1128/aem.01385-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 07/10/2018] [Indexed: 12/20/2022] Open
Abstract
Streptococcus suis is an important Gram-positive pathogen in the swine industry and is an emerging zoonotic pathogen for humans. In our previous work, we found a virulent S. suis strain, CZ130302, belonging to a novel serotype, Chz, to be associated with acute meningitis in piglets. However, its underlying mechanisms of pathogenesis remain poorly understood. In this study, we sequenced and analyzed the complete genomes of three Chz serotype strains, including strain CZ130302 and two avirulent strains, HN136 and AH681. By genome comparison, we found two putative genomic islands (GIs) uniquely encoded in strain CZ130302 and designated them 50K GI and 58K GI. In mouse infection model, the deletion of 50K and 58K GIs caused 270-fold and 3-fold attenuation of virulence, respectively. Notably, we identified a complete SecY2/A2 system, coupled with its secretory protein SssP1 encoded in the 50K GI, which contributed to the pathogenicity of strain CZ130302. Immunogold electron microscopy and immunofluorescence analyses indicated that SssP1 could form fimbria-like structures that extend outward from the bacterial cell surface. The sssP1 mutation also attenuated bacterial adherence in human laryngeal epithelial (HEp-2) cells and human brain microvessel endothelial cells (HBMECs) compared with the wild type. Furthermore, we showed that two analogous Ig-like subdomains of SssP1 have sialic acid binding capacities. In conclusion, our results revealed that the 50K GI and the inside SecY2/A2 system gene cluster are related to the virulence of strain CZ130302, and we clarified a new S. suis pathogenesis mechanism mediated by the secretion protein SssP1.IMPORTANCE Streptococcus suis is an important zoonotic pathogen. Here, we managed to identify key factors to clarify the virulence of S. suis strain CZ130302 from a novel serotype, Chz. Notably, it was shown that a fimbria-like structure was significantly connected to the pathogenicity of the CZ130302 strain by comparative genomics analysis and animal infection assays. The mechanisms of how the CZ130302 strain constructs these fimbria-like structures in the cell surface by genes encoding and production transport were subsequently elucidated. Biosynthesis of the fimbria-like structure was achieved by the production of SssP1 glycoproteins, and its construction was dependent on the SecA2/Y2 secretion system. This study identified a visible fimbria-like protein, SssP1, participating in adhesion to host cells and contributing to the virulence in S. suis These findings will promote a better understanding of the pathogenesis of S. suis.
Collapse
|
16
|
Protasova IN, Wan TW, Bakhareva NV, Hung WC, Higuchi W, Iwao Y, Yelistratova TA, Ilyenkova NA, Sokolovskaya YS, Martynova GP, Reva IV, Reva GV, Sidorenko SV, Teng LJ, Peryanova OV, Salmina AB, Yamamoto T. Molecular characterization of Streptococcus pneumoniae, particularly serotype19A/ST320, which emerged in Krasnoyarsk, Russia. Microbiol Immunol 2018; 61:359-370. [PMID: 28736993 PMCID: PMC5639370 DOI: 10.1111/1348-0421.12503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 06/30/2017] [Accepted: 07/17/2017] [Indexed: 12/18/2022]
Abstract
Streptococcus pneumoniae, a common human pathogen, colonizes the nasopharynx and causes diseases including acute otitis media (AOM). Herein, pneumococcal serotype distributions in children before and after PCV7 vaccination and in patients with pneumococcal disease in Siberian Russia (Krasnoyarsk) are reported. Analyses included antimicrobial susceptibility testing, sequence typing (ST), pulsed field gel electrophoresis, virulence‐related surface protein gene (VSG) typing with novel primers and structural analysis by scanning electron microscopy. In healthy children (HC) prior to administration of PCV7, drug‐susceptible serotype23F/ST1500 was a major pneumococcal genotype. In the PCV7 trial, multidrug‐resistant serotype19A/ST320 emerged in vaccinees after PCV7, exhibiting a PCV7‐induced serotype replacement. Multidrug‐resistant serotype19A/ST320 was evident in patients with AOM. Community‐acquired pneumonia (CAP) isolates showed genetic similarities to the AOM (ST320) genotype, constituting a common non‐invasive AOM–CAP group. In contrast, meningitis isolates were more divergent. Overall, 25 ST types were identified; five (20%) of which were Krasnoyarsk‐native. Regarding VSGs, PI‐1 (rlrA/rrgB), PI‐2 (pitA/B), psrP and cbpA were present at 54.3%, 38.6%, 48.6%, and 95.7%, respectively, with two major VSG content types, PI‐1−/PI‐2−/psrP+/cbpA+ and PI‐1+/PI‐2+/psrP‐/cbpA+, being found for HC and non‐invasive diseases, respectively. A major clone of serotype19A/ST320 (PI‐1+/PI‐2+) produced the longest pneumococcal wire (pilus) structures in colonies. ST1016 (PI‐1−/PI‐2−) in HC had HEp‐2 cell‐adherent pili. These results suggest that serotype19A/ST320 and related genotypes, with the VSG content type PI‐1+/PI‐2+/psrP−/cbpA+, emerged in vaccinees after PCV7 in Siberia, accompanying diseases in non‐vaccinated children, and that some genotypes (serotypes19A/ST320 and 18/ST1016) produced novel pneumococcal structures, predicting their roles in colony formation and adherence.
Collapse
Affiliation(s)
- Irina N Protasova
- Russia-Japan Center of Microbiology, Metagenomics and Infectious Diseases, Krasnoyarsk, Russia.,Department of Microbiology Krasnoyarsk State Medical University, Krasnoyarsk, Russia.,Department of Epidemiology, Genomics, and Evolution, International Medical Education and Research, Center Niigata, Japan
| | - Tsai-Wen Wan
- Department of Epidemiology, Genomics, and Evolution, International Medical Education and Research, Center Niigata, Japan.,Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan
| | | | - Wei-Chun Hung
- Department of Epidemiology, Genomics, and Evolution, International Medical Education and Research, Center Niigata, Japan.,Department of Microbiology and Immunology, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Wataru Higuchi
- Division of Bacteriology, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yasuhisa Iwao
- Department of Epidemiology, Genomics, and Evolution, International Medical Education and Research, Center Niigata, Japan
| | | | | | | | - Galina P Martynova
- Department of Children Infectious Diseases, Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Ivan V Reva
- Department of Epidemiology, Genomics, and Evolution, International Medical Education and Research, Center Niigata, Japan.,Department of Clinical and Fundamental Medicine, Far Eastern Federal University School of Biomedicine, Vladivostok, Russia
| | - Galina V Reva
- Department of Clinical and Fundamental Medicine, Far Eastern Federal University School of Biomedicine, Vladivostok, Russia
| | - Sergey V Sidorenko
- Research Institute of Children Infections of Federal State Medical and Biological Agency of Russia, Saint Petersburg
| | - Lee-Jene Teng
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Olga V Peryanova
- Russia-Japan Center of Microbiology, Metagenomics and Infectious Diseases, Krasnoyarsk, Russia.,Department of Microbiology Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Alla B Salmina
- Research Institute of Molecular Medicine and Pathobiochemistry, Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Tatsuo Yamamoto
- Russia-Japan Center of Microbiology, Metagenomics and Infectious Diseases, Krasnoyarsk, Russia.,Department of Epidemiology, Genomics, and Evolution, International Medical Education and Research, Center Niigata, Japan
| |
Collapse
|
17
|
Hakansson AP, Orihuela CJ, Bogaert D. Bacterial-Host Interactions: Physiology and Pathophysiology of Respiratory Infection. Physiol Rev 2018; 98:781-811. [PMID: 29488821 PMCID: PMC5966719 DOI: 10.1152/physrev.00040.2016] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 09/08/2017] [Accepted: 09/11/2017] [Indexed: 02/06/2023] Open
Abstract
It has long been thought that respiratory infections are the direct result of acquisition of pathogenic viruses or bacteria, followed by their overgrowth, dissemination, and in some instances tissue invasion. In the last decades, it has become apparent that in contrast to this classical view, the majority of microorganisms associated with respiratory infections and inflammation are actually common members of the respiratory ecosystem and only in rare circumstances do they cause disease. This suggests that a complex interplay between host, environment, and properties of colonizing microorganisms together determines disease development and its severity. To understand the pathophysiological processes that underlie respiratory infectious diseases, it is therefore necessary to understand the host-bacterial interactions occurring at mucosal surfaces, along with the microbes inhabiting them, during symbiosis. Current knowledge regarding host-bacterial interactions during asymptomatic colonization will be discussed, including a plausible role for the human microbiome in maintaining a healthy state. With this as a starting point, we will discuss possible disruptive factors contributing to dysbiosis, which is likely to be a key trigger for pathobionts in the development and pathophysiology of respiratory diseases. Finally, from this renewed perspective, we will reflect on current and potential new approaches for treatment in the future.
Collapse
Affiliation(s)
- A P Hakansson
- Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University , Lund , Sweden ; Department of Microbiology, University of Alabama at Birmingham , Birmingham, Alabama ; and Center for Inflammation Research, Queens Medical Research Institute, University of Edinburgh , Edinburgh , United Kingdom
| | - C J Orihuela
- Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University , Lund , Sweden ; Department of Microbiology, University of Alabama at Birmingham , Birmingham, Alabama ; and Center for Inflammation Research, Queens Medical Research Institute, University of Edinburgh , Edinburgh , United Kingdom
| | - D Bogaert
- Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University , Lund , Sweden ; Department of Microbiology, University of Alabama at Birmingham , Birmingham, Alabama ; and Center for Inflammation Research, Queens Medical Research Institute, University of Edinburgh , Edinburgh , United Kingdom
| |
Collapse
|
18
|
Detecting ligand interactions in real time on living bacterial cells. Appl Microbiol Biotechnol 2018; 102:4193-4201. [PMID: 29550990 PMCID: PMC5895670 DOI: 10.1007/s00253-018-8919-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 03/05/2018] [Accepted: 03/06/2018] [Indexed: 11/04/2022]
Abstract
Time-resolved analysis assays of receptor-ligand interactions are fundamental in basic research and drug discovery. Adequate methods are well developed for the analysis of recombinant proteins such as antibody-antigen interactions. However, assays for time-resolved ligand-binding processes on living cells are still rare, in particular within microbiology. In this report, the real-time cell-binding assay (RT-CBA) technology LigandTracer®, originally designed for mammalian cell culture, was extended to cover Gram-positive and Gram-negative bacteria. This required the development of new immobilization methods for bacteria, since LigandTracer depends on cells being firmly attached to a Petri dish. The evaluated Escherichia coli CJ236 and BL21 as well as Staphylococcus carnosus TM300 strains were immobilized to plastic Petri dishes using antibody capture, allowing us to depict kinetic binding traces of fluorescently labeled antibodies directed against surface-displayed bacterial proteins for as long as 10–15 h. Interaction parameters, such as the affinity and kinetic constants, could be estimated with high precision (coefficient of variation 9–44%) and the bacteria stayed viable for at least 16 h. The other tested attachment protocols were inferior to the antibody capture approach. Our attachment protocol is generic and could potentially also be applied to other assays and purposes.
Collapse
|
19
|
Structural basis for the role of serine-rich repeat proteins from Lactobacillus reuteri in gut microbe-host interactions. Proc Natl Acad Sci U S A 2018; 115:E2706-E2715. [PMID: 29507249 PMCID: PMC5866549 DOI: 10.1073/pnas.1715016115] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Gut bacteria play a key role in health and disease, but the molecular mechanisms underpinning their interaction with the host remain elusive. The serine-rich repeat proteins (SRRPs) are a family of adhesins identified in many Gram-positive pathogenic bacteria. We previously showed that beneficial bacterial species found in the gut also express SRRPs and that SRRP was required for the ability of Lactobacillus reuteri strain to colonize mice. Here, our structural and biochemical data reveal that L. reuteri SRRP adopts a β-solenoid fold not observed in other structurally characterized SRRPs and functions as an adhesin via a pH-dependent mechanism, providing structural insights into the role of these adhesins in biofilm formation of gut symbionts. Lactobacillus reuteri, a Gram-positive bacterial species inhabiting the gastrointestinal tract of vertebrates, displays remarkable host adaptation. Previous mutational analyses of rodent strain L. reuteri 100-23C identified a gene encoding a predicted surface-exposed serine-rich repeat protein (SRRP100-23) that was vital for L. reuteri biofilm formation in mice. SRRPs have emerged as an important group of surface proteins on many pathogens, but no structural information is available in commensal bacteria. Here we report the 2.00-Å and 1.92-Å crystal structures of the binding regions (BRs) of SRRP100-23 and SRRP53608 from L. reuteri ATCC 53608, revealing a unique β-solenoid fold in this important adhesin family. SRRP53608-BR bound to host epithelial cells and DNA at neutral pH and recognized polygalacturonic acid (PGA), rhamnogalacturonan I, or chondroitin sulfate A at acidic pH. Mutagenesis confirmed the role of the BR putative binding site in the interaction of SRRP53608-BR with PGA. Long molecular dynamics simulations showed that SRRP53608-BR undergoes a pH-dependent conformational change. Together, these findings provide mechanistic insights into the role of SRRPs in host–microbe interactions and open avenues of research into the use of biofilm-forming probiotics against clinically important pathogens.
Collapse
|
20
|
Lizcano A, Akula Suresh Babu R, Shenoy AT, Saville AM, Kumar N, D'Mello A, Hinojosa CA, Gilley RP, Segovia J, Mitchell TJ, Tettelin H, Orihuela CJ. Transcriptional organization of pneumococcal psrP-secY2A2 and impact of GtfA and GtfB deletion on PsrP-associated virulence properties. Microbes Infect 2017; 19:323-333. [PMID: 28408270 PMCID: PMC5581956 DOI: 10.1016/j.micinf.2017.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 03/10/2017] [Accepted: 04/03/2017] [Indexed: 01/08/2023]
Abstract
Pneumococcal serine-rich repeat protein (PsrP) is a glycoprotein that mediates Streptococcus pneumoniae attachment to lung cells and promotes biofilm formation. Herein, we investigated the transcriptional organization of psrP-secY2A2, the 37-kbp pathogenicity island encoding PsrP and its accessory genes. PCR amplification of cDNA and RNA-seq analysis found psrP-secY2A2 to be minimally composed of three operons: psrP-glyA, glyB, and glyC-asp5. Transcription of all three operons was greatest during biofilm growth and immunoblot analyses confirmed increased PsrP production by biofilm pneumococci. Using gas chromatography-mass spectrometry we identified monomeric N-acetylglucosamine as the primary glycoconjugate present on a recombinant intracellular version of PsrP, i.e. PsrP1-734. This finding was validated by immunoblot using lectins with known carbohydrate specificities. We subsequently deleted gtfA and gtfB, the GTFs thought to be responsible for addition of O-linked N-acetylglucosamine, and tested for PsrP and its associated virulence properties. These deletions negatively affected our ability to detect PsrP1-734 in bacterial whole cell lysates. Moreover, S. pneumoniae mutants lacking these genes pheno-copied the psrP mutant and were attenuated for: biofilm formation, adhesion to lung epithelial cells, and pneumonia in mice. Our studies identify the transcriptional organization of psrP-secY2A2 and show the indispensable role of GtfA and GtfB on PsrP-mediated pneumococcal virulence.
Collapse
Affiliation(s)
- Anel Lizcano
- Department of Microbiology and Immunology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Ramya Akula Suresh Babu
- Department of Microbiology and Immunology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Anukul T Shenoy
- Department of Microbiology and Immunology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Alison Maren Saville
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
| | - Nikhil Kumar
- Department of Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Adonis D'Mello
- Department of Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Cecilia A Hinojosa
- Department of Microbiology and Immunology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Ryan P Gilley
- Department of Microbiology and Immunology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Jesus Segovia
- Department of Microbiology and Immunology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Timothy J Mitchell
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G12 8QQ, Scotland, UK; Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Hervé Tettelin
- Department of Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Carlos J Orihuela
- Department of Microbiology and Immunology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| |
Collapse
|
21
|
Bandara M, Skehel JM, Kadioglu A, Collinson I, Nobbs AH, Blocker AJ, Jenkinson HF. The accessory Sec system (SecY2A2) in Streptococcus pneumoniae is involved in export of pneumolysin toxin, adhesion and biofilm formation. Microbes Infect 2017; 19:402-412. [PMID: 28456649 PMCID: PMC5526788 DOI: 10.1016/j.micinf.2017.04.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 03/27/2017] [Accepted: 04/17/2017] [Indexed: 01/04/2023]
Abstract
In Streptococcus pneumoniae TIGR4, genes encoding a SecY2A2 accessory Sec system are present within a locus encoding a serine-rich repeat surface protein PsrP. Mutant strains deleted in secA2 or psrP were deficient in biofilm formation, while the ΔsecA2 mutant was reduced in binding to airway epithelial cells. Cell wall protein (CWP) fractions from the ΔsecA2 mutant, but not from the ΔpsrP mutant, were reduced in haemolytic (pneumolysin) activity. Contact-dependent pneumolysin (Ply) activity of wild type TIGR4 cells was ten-fold greater than that of ΔsecA2 mutant cells suggesting that Ply was not active at the ΔsecA2 cell surface. Ply protein was found to be present in the CWP fraction from the ΔsecA2 mutant, but showed aberrant electrophoretic migration indicative of protein modification. Proteomic analyses led to the discovery that the ΔsecA2 mutant CWP fraction was deficient in two glycosidases as well as other enzymes involved in carbohydrate metabolism. Taken collectively the results suggest that positioning of Ply into the cell wall compartment in active form, together with glycosyl hydrolases and adhesins, requires a functional accessory Sec system.
Collapse
Affiliation(s)
- Mikaila Bandara
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol, BS1 2LY, UK; School of Cellular & Molecular Medicine, University of Bristol, University Walk, Bristol, BS8 1TD, UK; School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - J Mark Skehel
- Biological Mass Spectrometry and Proteomics, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Aras Kadioglu
- Department of Clinical Infection, Microbiology & Immunology, Institute of Infection and Global Health, University of Liverpool, 8 West Derby Street, Liverpool L69 7BE, UK
| | - Ian Collinson
- School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Angela H Nobbs
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol, BS1 2LY, UK
| | - Ariel J Blocker
- School of Cellular & Molecular Medicine, University of Bristol, University Walk, Bristol, BS8 1TD, UK; School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK.
| | - Howard F Jenkinson
- School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol, BS1 2LY, UK.
| |
Collapse
|
22
|
Jiang YL, Jin H, Yang HB, Zhao RL, Wang S, Chen Y, Zhou CZ. Defining the enzymatic pathway for polymorphic O-glycosylation of the pneumococcal serine-rich repeat protein PsrP. J Biol Chem 2017; 292:6213-6224. [PMID: 28246170 DOI: 10.1074/jbc.m116.770446] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 02/17/2017] [Indexed: 12/30/2022] Open
Abstract
Protein O-glycosylation is an important post-translational modification in all organisms, but deciphering the specific functions of these glycans is difficult due to their structural complexity. Understanding the glycosylation of mucin-like proteins presents a particular challenge as they are modified numerous times with both the enzymes involved and the glycosylation patterns being poorly understood. Here we systematically explored the O-glycosylation pathway of a mucin-like serine-rich repeat protein PsrP from the human pathogen Streptococcus pneumoniae TIGR4. Previous works have assigned the function of 3 of the 10 glycosyltransferases thought to modify PsrP, GtfA/B, and Gtf3 as catalyzing the first two reactions to form a unified disaccharide core structure. We now use in vivo and in vitro glycosylation assays combined with hydrolytic activity assays to identify the glycosyltransferases capable of decorating this core structure in the third and fourth steps of glycosylation. Specifically, the full-length GlyE and GlyG proteins and the GlyD DUF1792 domain participate in both steps, whereas full-length GlyA and the GlyD GT8 domain catalyze only the fourth step. Incorporation of different sugars to the disaccharide core structure at multiple sites along the serine-rich repeats results in a highly polymorphic product. Furthermore, crystal structures of apo- and UDP-complexed GlyE combined with structural analyses reveal a novel Rossmann-fold "add-on" domain that we speculate to function as a universal module shared by GlyD, GlyE, and GlyA to forward the peptide acceptor from one enzyme to another. These findings define the complete glycosylation pathway of a bacterial glycoprotein and offer a testable hypothesis of how glycosyltransferase coordination facilitates glycan assembly.
Collapse
Affiliation(s)
- Yong-Liang Jiang
- From the Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China and.,Key Laboratory of Structural Biology, Chinese Academy of Science, Hefei, Anhui 230027, China
| | - Hua Jin
- From the Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China and.,Key Laboratory of Structural Biology, Chinese Academy of Science, Hefei, Anhui 230027, China
| | - Hong-Bo Yang
- From the Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China and.,Key Laboratory of Structural Biology, Chinese Academy of Science, Hefei, Anhui 230027, China
| | - Rong-Li Zhao
- From the Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China and.,Key Laboratory of Structural Biology, Chinese Academy of Science, Hefei, Anhui 230027, China
| | - Shiliang Wang
- From the Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China and
| | - Yuxing Chen
- From the Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China and .,Key Laboratory of Structural Biology, Chinese Academy of Science, Hefei, Anhui 230027, China
| | - Cong-Zhao Zhou
- From the Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China and .,Key Laboratory of Structural Biology, Chinese Academy of Science, Hefei, Anhui 230027, China
| |
Collapse
|
23
|
Arenas J, Tommassen J. Meningococcal Biofilm Formation: Let's Stick Together. Trends Microbiol 2017; 25:113-124. [DOI: 10.1016/j.tim.2016.09.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 09/13/2016] [Accepted: 09/16/2016] [Indexed: 11/26/2022]
|
24
|
Domenech M, García E. N-Acetyl-l-Cysteine and Cysteamine as New Strategies against Mixed Biofilms of Nonencapsulated Streptococcus pneumoniae and Nontypeable Haemophilus influenzae. Antimicrob Agents Chemother 2017; 61:e01992-16. [PMID: 27919900 PMCID: PMC5278723 DOI: 10.1128/aac.01992-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 11/29/2016] [Indexed: 12/20/2022] Open
Abstract
Acute otitis media, a polymicrobial disease of the middle ear cavity of children, is a significant public health problem worldwide. It is most frequently caused by encapsulated Streptococcus pneumoniae and nontypeable Haemophilus influenzae, although the widespread use of pneumococcal conjugate vaccines is apparently producing an increase in the carriage of nonencapsulated S. pneumoniae Frequently, pneumococci and H. influenzae live together in the human nasopharynx, forming a self-produced biofilm. Biofilms present a global medical challenge since the inherent antibiotic resistance of their producers demands the use of large doses of antibiotics over prolonged periods. Frequently, these therapeutic measures fail, contributing to bacterial persistence. Here, we describe the development of an in vitro nonencapsulated S. pneumoniae-nontypeable H. influenzae biofilm system with polystyrene or glass-bottom plates. Confocal laser scanning microscopy and specific fluorescent labeling of pneumococcal cells with Helix pomatia agglutinin revealed an even distribution of both species within the biofilm. This simple and robust protocol of mixed biofilms was used to test the antimicrobial properties of two well-known antioxidants that are widely used in the clinical setting, i.e., N-acetyl-l-cysteine and cysteamine. This repurposing approach showed the high potency of N-acetyl-l-cysteine and cysteamine against mixed biofilms of nonencapsulated S. pneumoniae and nontypeable H. influenzae Decades of clinical use mean that these compounds are safe to use, which may accelerate their evaluation in humans.
Collapse
Affiliation(s)
- Mirian Domenech
- Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Ernesto García
- Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| |
Collapse
|