1
|
Franco EM, Alves LA, Naveed H, Freitas VAA, Bastos DC, Mattos-Graner RO. Amyloid Fibrils Produced by Streptococcus sanguinis Contribute to Biofilm Formation and Immune Evasion. Int J Mol Sci 2023; 24:15686. [PMID: 37958670 PMCID: PMC10647432 DOI: 10.3390/ijms242115686] [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: 10/06/2023] [Accepted: 10/20/2023] [Indexed: 11/15/2023] Open
Abstract
Bacterial surface proteins assembled into amyloids contribute to biofilm formation and host immune evasion. Streptococcus sanguinis, a pioneer colonizer of teeth commonly involved in cardiovascular infections, expresses about thirty-three proteins anchored to the cell wall by sortase A. Here, we characterized the production of amyloid in S. sanguinis strains differing in biofilm and immune evasion phenotypes and investigated the role of sortase A in amyloidogenesis. Amyloid was identified in biofilms formed by nine strains, using Congo red (CR) staining and cross-polarized light microscopy. Additionally, EGCG, an amyloid inhibitor, impaired biofilm maturation in a strain-specific fashion. The amounts of amyloid-like components quantified in culture fluids of nine strains using thioflavin T and fluorimetry negatively correlated with bacterial binding to complement-activating proteins (SAP, C1q), C3b deposition and rates of opsonophagocytosis in PMNs, implying amyloid production in immune evasion. The deletion of the sortase A gene (srtA) in strain SK36 compromised amyloid production and sucrose-independent biofilm maturation. The srtA mutant further showed increased susceptibility to C3b deposition and altered interactions with PMNs as well as reduced persistence in human blood. These findings highlight the contribution of amyloids to biofilm formation and host immune evasion in S. sanguinis strains, further indicating the participation of sortase A substrates in amyloidogenesis.
Collapse
Affiliation(s)
- Eduardo M. Franco
- Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Piracicaba 13414-903, SP, Brazil; (E.M.F.); (L.A.A.); (H.N.); (V.A.A.F.)
| | - Lívia A. Alves
- Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Piracicaba 13414-903, SP, Brazil; (E.M.F.); (L.A.A.); (H.N.); (V.A.A.F.)
- School of Dentistry, Cruzeiro do Sul University (UNICSUL), São Paulo 01506-000, SP, Brazil
| | - Hassan Naveed
- Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Piracicaba 13414-903, SP, Brazil; (E.M.F.); (L.A.A.); (H.N.); (V.A.A.F.)
| | - Victor A. A. Freitas
- Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Piracicaba 13414-903, SP, Brazil; (E.M.F.); (L.A.A.); (H.N.); (V.A.A.F.)
| | - Débora C. Bastos
- Department of Biosciences, Piracicaba Dental School, State University of Campinas, Piracicaba 13414-903, SP, Brazil;
- São Leopoldo Mandic Medical School, Campinas 13045-755, SP, Brazil
| | - Renata O. Mattos-Graner
- Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Piracicaba 13414-903, SP, Brazil; (E.M.F.); (L.A.A.); (H.N.); (V.A.A.F.)
| |
Collapse
|
2
|
Structures of Streptococcus pyogenes Class A sortase in complex with substrate and product mimics provide key details of target recognition. J Biol Chem 2022; 298:102446. [PMID: 36055407 PMCID: PMC9520033 DOI: 10.1016/j.jbc.2022.102446] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 08/24/2022] [Accepted: 08/25/2022] [Indexed: 12/02/2022] Open
Abstract
The cell wall is a critical extracellular barrier for bacteria and many other organisms. In bacteria, this structural layer consists of peptidoglycan, which maintains cell shape and structural integrity and provides a scaffold for displaying various protein factors. To attach proteins to the cell wall, Gram-positive bacteria utilize sortase enzymes, which are cysteine transpeptidases that recognize and cleave a specific sorting signal, followed by ligation of the sorting signal–containing protein to the peptidoglycan precursor lipid II (LII). This mechanism is the subject of considerable interest as a target for therapeutic intervention and as a tool for protein engineering, where sortases have enabled sortase-mediated ligation or sortagging strategies. Despite these uses, there remains an incomplete understanding of the stereochemistry of substrate recognition and ligation product formation. Here, we solved the first structures of sortase A from Streptococcus pyogenes bound to two substrate sequences, LPATA and LPATS. In addition, we synthesized a mimetic of the product of sortase-mediated ligation involving LII (LPAT-LII) and solved the complex structure in two ligand conformations. These structures were further used as the basis for molecular dynamics simulations to probe sortase A-ligand dynamics and to construct a model of the acyl–enzyme intermediate, thus providing a structural view of multiple key states in the catalytic mechanism. Overall, this structural information provides new insights into the recognition of the sortase substrate motif and LII ligation partner and will support the continued development of sortases for protein engineering applications.
Collapse
|
3
|
Banerji R, Iyer P, Bhagwat A, Saroj SD. Spermidine promotes lysozyme tolerance and acid stress resistance in Streptococcus pyogenes M3. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35917154 DOI: 10.1099/mic.0.001228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Streptococcus pyogenes are Gram-positive opportunistic pathogens residing in the human nasopharynx and skin. Changes in environmental conditions, such as pH, temperature and availability of essential ions, can stimulate the expression of S. pyogenes virulence factors. One such factor could be the availability of an extracellular pool of polyamines. Polyamines are synthesized from amino acids, and are universally present in the environment. Polyamines have been implicated in the ecology of pathogenesis by modulating quorum sensing, host adaptation and virulence. Polyamines mediate pathogenesis and help the pathogen resist environmental stress. In this study, we investigated the ability of the polyamine, spermidine, to promote acid stress survival of S. pyogenes. S. pyogenes does not synthesize spermidine, but the extracellular pool of spermidine constituted by the host and microbiome could be utilized as a signalling molecule. We report that spermidine promotes acid stress resistance in S. pyogenes. Moreover, spermidine affects the morphology of S. pyogenes by decreasing the cell size and increasing the dltA gene expression. Along with dltA, spermidine upregulated the gene expression of cell wall-modifying genes such as mur, pgdA, pepO and srtA, which might help the bacteria to resist acidic stress.
Collapse
Affiliation(s)
- Rajashri Banerji
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Symbiosis Knowledge Village, Lavale Pune 412115, Maharashtra, India
| | - Parvati Iyer
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Symbiosis Knowledge Village, Lavale Pune 412115, Maharashtra, India
| | - Amrita Bhagwat
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Symbiosis Knowledge Village, Lavale Pune 412115, Maharashtra, India
| | - Sunil D Saroj
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Symbiosis Knowledge Village, Lavale Pune 412115, Maharashtra, India
| |
Collapse
|
4
|
Katsumata T, Nguyen-Tra Le M, Kawada-Matsuo M, Taniguchi Y, Ouhara K, Oogai Y, Nakata M, Mizuno N, Nishitani Y, Komatsuzawa H. KATSUMATA et al.Comprehensive characterization of sortase A-dependent surface proteins in Streptococcus mutansComprehensive characterization of sortase A-dependent surface proteins in Streptococcus mutans. Microbiol Immunol 2021; 66:145-156. [PMID: 34888908 DOI: 10.1111/1348-0421.12958] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 11/30/2021] [Accepted: 12/01/2021] [Indexed: 11/29/2022]
Abstract
Streptococcus mutans, a cariogenic pathogen, adheres to the tooth surface and forms a biofilm. Bacterial cell surface proteins are associated with adherence to substrates. Sortase A (SrtA) mediates the localization of proteins with an LPXTG motif-containing proteins to the cell surface by covalent binding to peptidoglycan. In S. mutans UA159, 6 SrtA-dependent proteins, SpaP, WapA, WapE, DexA, FruA, and GbpC, were identified. Although some of these proteins were characterized, a comprehensive analysis of the 6 proteins has not been reported. In this study, we constructed mutants deficient in each of these proteins and the SrtA-deficient mutant. The SrtA-deficient mutant showed drastically decreased binding to salivary components, biofilm formation, bacterial coaggregation activity, hydrophobicity, and cellular matrix binding (collagen type I, fibronectin, and laminin). The SpaP-deficient mutant showed significantly reduced binding to salivary components and partially increased coaggregation with Porphyromonas gingivalis, and decreased hydrophobicity, and collagen binding. The WapA-deficient mutant showed slightly decreased coaggregation with Fusobacterium nucleatum. Although the SrtA-deficient mutant showed drastically altered phenotypes, all SrtA-dependent protein-deficient mutants, except the SpaP-deficient mutant, did not show considerable alterations in binding to salivary components. These results indicate that the 6 proteins may coordinately contribute to these activities. In addition, using genomic data of 125 S. mutans strains, we compared the amino acid sequences of each surface protein and found many variations among strains, which may affect the phenotype of cell surface proteins in S. mutans. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Tamaki Katsumata
- Department of Restorative Dentistry and Endodontology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Mi Nguyen-Tra Le
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Miki Kawada-Matsuo
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Yuri Taniguchi
- Department of Periodontal Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Kazuhisa Ouhara
- Department of Periodontal Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Yuichi Oogai
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Masanobu Nakata
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Noriyoshi Mizuno
- Department of Periodontal Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Yoshihiro Nishitani
- Department of Restorative Dentistry and Endodontology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Hitoshi Komatsuzawa
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| |
Collapse
|
5
|
Esmail GA, Al-Dhabi NA, AlDawood B, Somily AM. Shotgun whole genome sequencing of drug-resistance Streptococcus anginosus strain 47S1 isolated from a patient with pharyngitis in Saudi Arabia. J Infect Public Health 2021; 14:1740-1749. [PMID: 34836797 DOI: 10.1016/j.jiph.2021.11.010] [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: 10/03/2021] [Revised: 11/03/2021] [Accepted: 11/09/2021] [Indexed: 10/19/2022] Open
Abstract
BACKGROUND Streptococcus anginosus is an emergence opportunistic pathogen that colonize the human upper respiratory tract (URT), S. anginosus alongside with S. intermedius and S. constellatus, members of S. anginosus group, are implicated in several human infections. However, our understanding this bacterium to the genotype level with determining the genes associated with pathogenicity and antimicrobial resistance (AMR) is scarce. S. anginosus 47S1 strain was isolated from sore throat infection, the whole genome was characterized and the virulence & AMR genes contributing in pathogenicity were investigated. METHODOLOGY The whole genome of 47S1 was sequenced by Illumina sequencing technology. Strain 47S1 genome was de novo assembled with different strategies and annotated via PGAP, PROKKA and RAST pipelines. Identifying the CRISPR-Cass system and prophages sequences was performed using CRISPRloci and PhiSpy tools respectively. Prediction the virulence genes were performed with the VFDB database. AMR genes were detected in silico using NCBI AMRFinderPlus pipeline and CARD database and compared with in vitro AST findings. RESULTS β-hemolytic strain 47S1 was identified with conventional microbiology techniques and confirmed by the sequences of 16S rRNA gene. Genome of 47S1 comprised of 1981512 bp. Type I-C CRISPR-Cas system and 4 prophages were detected among the genome of 47S1. Several virulence genes were predicted, most of these genes are found in other pathogenic streptococci, mainly lmb, pavA, htrA/degP, eno, sagA, psaA and cpsI which play a significant role in colonizing, invading host tissues and evade form immune system. In silico AMR findings showed that 47S1 gnome harbors (tetA, tetB &tet32), (aac(6')-I, aadK &aph(3')-IVa), fusC, and PmrA genes that mediated-resistance to tetracyclines, aminoglycosides, fusidic acid, and fluoroquinolone respectively which corresponds with in vitro AST obtained results. In conclusion, WGS is a key approach to predict the virulence and AMR genes, results obtained in this study may contribute for a better understanding of the opportunistic S. anginosus pathogenicity.
Collapse
Affiliation(s)
- Galal Ali Esmail
- Department of Botany and Microbiology, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Naif Abdullah Al-Dhabi
- Department of Botany and Microbiology, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.
| | - Badr AlDawood
- Department of Emergency Medicine, College of Medicine, King Saud University, King Saud University Medical City, Riyadh 11461, Saudi Arabia
| | - Ali Mohammed Somily
- Department of Pathology and Laboratory Medicine/Microbiology, College of Medicine, King Saud University, King Saud University Medical City, Riyadh 11461, Saudi Arabia.
| |
Collapse
|
6
|
Susmitha A, Bajaj H, Madhavan Nampoothiri K. The divergent roles of sortase in the biology of Gram-positive bacteria. ACTA ACUST UNITED AC 2021; 7:100055. [PMID: 34195501 PMCID: PMC8225981 DOI: 10.1016/j.tcsw.2021.100055] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/11/2021] [Accepted: 06/11/2021] [Indexed: 12/16/2022]
Abstract
The bacterial cell wall contains numerous surface-exposed proteins, which are covalently anchored and assembled by a sortase family of transpeptidase enzymes. The sortase are cysteine transpeptidases that catalyzes the covalent attachment of surface protein to the cell wall peptidoglycan. Among the reported six classes of sortases, each distinct class of sortase plays a unique biological role in anchoring a variety of surface proteins to the peptidoglycan of both pathogenic and non-pathogenic Gram-positive bacteria. Sortases not only exhibit virulence and pathogenesis properties to host cells, but also possess a significant role in gut retention and immunomodulation in probiotic microbes. The two main distinct functions are to attach proteins directly to the cell wall or assemble pili on the microbial surface. This review provides a compendium of the distribution of different classes of sortases present in both pathogenic and non-pathogenic Gram-positive bacteria and also the noteworthy role played by them in bacterial cell wall assembly which enables each microbe to effectively interact with its environment.
Collapse
Affiliation(s)
- Aliyath Susmitha
- Microbial Processes and Technology Division, CSIR - National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695019, Kerala, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Harsha Bajaj
- Microbial Processes and Technology Division, CSIR - National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695019, Kerala, India
| | - Kesavan Madhavan Nampoothiri
- Microbial Processes and Technology Division, CSIR - National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695019, Kerala, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| |
Collapse
|
7
|
Zhang H, Zhou T, Su L, Wang H, Zhang B, Su Y. Effects of srtA variation on phagocytosis resistance and immune response of Streptococcus equi. INFECTION GENETICS AND EVOLUTION 2021; 89:104732. [PMID: 33503504 DOI: 10.1016/j.meegid.2021.104732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 12/17/2020] [Accepted: 01/21/2021] [Indexed: 11/26/2022]
Abstract
Strangles, which is caused by Streptococcus equi subspecies equi (S. equi), is one of the most prevalent equine infectious diseases with worldwide distribution and leads to serious economic loss in the horse industry. Sortase A (srtA) is a transpeptidase that anchors multiple virulence-associated surface proteins to the cell surface of S. equi. srtA plays a major role in S. equi infection and colonization of the host cell. In this study, we aimed to investigate the effects of srtA mutation on the phagocytic activity and immunogenicity of S. equi. The point-mutated recombinant sortases, including srtA-HT1112 (I88V), srtA-5012 (R147G), and srtA-ZZM17 (control), were expressed, purified, and used to immunize the mouse models. Phagocytic activity was assessed using equine polymorphonuclear cells, whereas opsonophagocytic function and adherence inhibition were measured using the antiserum of these mutants. Mouse serum antibody, bacterial load, and weight gain were also measured. The srtA-HT1112 (I88V) mutant showed significantly enhanced antiphagocytic capability, and its antiserum exhibited increased adherence inhibition activity. In addition, the srtA-HT1112 (I88V) mutant presented the highest lung bacterial load and lowest protection rate (50%) after the challenge with S. equi ZZM17. The srtA-5012 (R147G) mutant exhibited a high IgG2a level and protection rate (62.5%-75%) and the lowest lung bacterial load. These results indicate that the I88V mutation is associated with a high antiphagocytic activity, whereas R147G mutation is associated with the decreased lung bacterial load. Our findings may be useful for the evaluation and development of vaccines.
Collapse
Affiliation(s)
- Huan Zhang
- Department of Microbiology and Immunology, College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Tingting Zhou
- Department of Microbiology and Immunology, College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Lining Su
- Xinjiang Academy of Animal Science, Urumqi, Xinjiang, China
| | - Hao Wang
- Department of Microbiology and Immunology, College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Baojiang Zhang
- Department of Microbiology and Immunology, College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Yan Su
- Department of Microbiology and Immunology, College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang, China.
| |
Collapse
|
8
|
Russo BT, Ayinuola YA, Singh D, Carothers K, Fischetti VA, Flores-Mireles AL, Lee SW, Ploplis VA, Liang Z, Castellino FJ. The M Protein of Streptococcus pyogenes Strain AP53 Retains Cell Surface Functional Plasminogen Binding after Inactivation of the Sortase A Gene. J Bacteriol 2020; 202:e00096-20. [PMID: 32123038 PMCID: PMC7186463 DOI: 10.1128/jb.00096-20] [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: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 12/11/2022] Open
Abstract
Streptococcus pyogenes (Lancefield group A Streptococcus [GAS]) is a β-hemolytic human-selective pathogen that is responsible for a large number of morbid and mortal infections in humans. For efficient infection, GAS requires different types of surface proteins that provide various mechanisms for evading human innate immune responses, thus enhancing pathogenicity of the bacteria. Many such virulence-promoting proteins, including the major surface signature M protein, are translocated after biosynthesis through the cytoplasmic membrane and temporarily tethered to this membrane via a type 1 transmembrane domain (TMD) positioned near the COOH terminus. In these proteins, a sorting signal, LPXTG, is positioned immediately upstream of the TMD, which is cleaved by the membrane-associated transpeptidase, sortase A (SrtA), leading to the covalent anchoring of these proteins to newly emerging l-Ala-l-Ala cross-bridges of the growing peptidoglycan cell wall. Herein, we show that inactivation of the srtA gene in a skin-tropic pattern D GAS strain (AP53) results in retention of the M protein in the cell membrane. However, while the isogenic AP53 ΔsrtA strain is attenuated in overall pathogenic properties due to effects on the integrity of the cell membrane, our data show that the M protein nonetheless can extend from the cytoplasmic membrane through the cell wall and then to the surface of the bacteria and thereby retain its important properties of productively binding and activating fluid-phase host plasminogen (hPg). The studies presented herein demonstrate an underappreciated additional mechanism of cell surface display of bacterial virulence proteins via their retention in the cell membrane and extension to the GAS surface.IMPORTANCE Group A Streptococcus pyogenes (GAS) is a human-specific pathogen that produces many surface factors, including its signature M protein, that contribute to its pathogenicity. M proteins undergo specific membrane localization and anchoring to the cell wall via the transpeptidase sortase A. Herein, we explored the role of sortase A function on M protein localization, architecture, and function, employing, a skin-tropic GAS isolate, AP53, which expresses a human plasminogen (hPg)-binding M (PAM) Protein. We showed that PAM anchored in the cell membrane, due to the targeted inactivation of sortase A, was nonetheless exposed on the cell surface and functionally interacted with host hPg. We demonstrate that M proteins, and possibly other sortase A-processed proteins that are retained in the cell membrane, can still function to initiate pathogenic processes by this underappreciated mechanism.
Collapse
Affiliation(s)
- Brady T Russo
- W. M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, Indiana, USA
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Yetunde A Ayinuola
- W. M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, Indiana, USA
| | - Damini Singh
- W. M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, Indiana, USA
| | - Katelyn Carothers
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Vincent A Fischetti
- Laboratory of Bacterial Pathogenesis and Immunology, Rockefeller University, New York, New York, USA
| | - Ana L Flores-Mireles
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Shaun W Lee
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Victoria A Ploplis
- W. M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, Indiana, USA
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Zhong Liang
- W. M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, Indiana, USA
| | - Francis J Castellino
- W. M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, Indiana, USA
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| |
Collapse
|
9
|
van Hensbergen VP, Wu Y, van Sorge NM, Touqui L. Type IIA Secreted Phospholipase A2 in Host Defense against Bacterial Infections. Trends Immunol 2020; 41:313-326. [PMID: 32151494 DOI: 10.1016/j.it.2020.02.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 02/07/2020] [Accepted: 02/08/2020] [Indexed: 12/13/2022]
Abstract
The enzyme type IIA secreted phospholipase A2 (sPLA2-IIA) is crucial for mammalian innate host defense against bacterial pathogens. Most studies have investigated the role of sPLA2-IIA in systemic bacterial infections, identifying molecular pathways of bacterial resistance against sPLA2-IIA-mediated killing, and providing insight into sPLA2-IIA mechanisms of action. Sensitization of (antibiotic-resistant) bacteria to sPLA2-IIA action by blocking bacterial resistance or by applying sPLA2-IIA to treat bacterial infections might represent a therapeutic option in the future. Because sPLA2-IIA is highly expressed at mucosal barriers, we also discuss how sPLA2-IIA is likely to be an important driver of microbiome composition; we anticipate that future research in this area may bring new insights into the role of sPLA2-IIA in health and disease.
Collapse
Affiliation(s)
- Vincent P van Hensbergen
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Yongzheng Wu
- Unité de Biologie Cellulaire de l'infection Microbienne, CNRS UMR3691, Institut Pasteur, Paris, France
| | - Nina M van Sorge
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.
| | - Lhousseine Touqui
- Mucoviscidose et Bronchopathies Chroniques, département Santé Globale; Pasteur Institute, Paris, France.
| |
Collapse
|
10
|
Nitulescu G, Mihai DP, Nicorescu IM, Olaru OT, Ungurianu A, Zanfirescu A, Nitulescu GM, Margina D. Discovery of natural naphthoquinones as sortase A inhibitors and potential anti-infective solutions against Staphylococcus aureus. Drug Dev Res 2019; 80:1136-1145. [PMID: 31486108 DOI: 10.1002/ddr.21599] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 08/09/2019] [Accepted: 08/14/2019] [Indexed: 12/11/2022]
Abstract
Three natural naphthoquinones were screened to find new anti-virulence agents as inhibitors against sortase A from Staphylococcus aureus (SaSrtA) by quantifying the increase in fluorescence intensity upon substrate cleavage at various concentrations. The 5-hydroxy-1,4-naphthalenedione derivatives, juglone and plumbagin, demonstrated a potent inhibitory effect, with IC50 values of 1.78 μM, respectively, 16.71 μM. The related 2-hydroxy-1,4-naphthalenedione derivative, lawsone, demonstrated the selectivity of the chemical scaffold having no significant effect on SaSrtA. The experimental assay was reinforced by molecular docking experiments, antimicrobial, and toxicological studies. Molecular docking studies and the electrophilic character analysis suggest bonding to the enzyme active cysteine residue by a Michael addition reaction. None of the compounds had a significant effect on the concentration of total thiol proteins in the Daphnia magna toxicological assay after 24 hr exposure. Juglone and plumbagin moderately inhibited biofilm formation with no significant effect on bacterial growth of S. aureus, Enterococcus faecalis, and Staphylococcus epidermidis, indicating a selective anti-virulence profile.
Collapse
Affiliation(s)
| | - Dragos P Mihai
- Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | | | - Octavian T Olaru
- Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Anca Ungurianu
- Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Anca Zanfirescu
- Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | | | - Denisa Margina
- Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| |
Collapse
|
11
|
Chen X, Liu C, Peng X, He Y, Liu H, Song Y, Xiong K, Zou L. Sortase A‐mediated modification of the
Streptococcus mutans
transcriptome and virulence traits. Mol Oral Microbiol 2019; 34:219-233. [PMID: 31342653 DOI: 10.1111/omi.12266] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 07/16/2019] [Accepted: 07/18/2019] [Indexed: 02/05/2023]
Affiliation(s)
- Xuan Chen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
| | - Chengcheng Liu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
- Department of Periodontics West China Hospital of Stomatology, Sichuan University Chengdu China
| | - Xian Peng
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
| | - Yuanli He
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
| | - Haixia Liu
- Stomatological Hospital of Chongqing Medical University Chongqing China
| | - Ying Song
- Stomatological Hospital of Chongqing Medical University Chongqing China
| | - Kaixin Xiong
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
| | - Ling Zou
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
- Department of Conservation Dentistry and Endodontics West China Hospital of Stomatology, Sichuan University Chengdu China
| |
Collapse
|
12
|
Sortase-Dependent Proteins Promote Gastrointestinal Colonization by Enterococci. Infect Immun 2019; 87:IAI.00853-18. [PMID: 30804098 DOI: 10.1128/iai.00853-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 02/18/2019] [Indexed: 12/19/2022] Open
Abstract
The human gastrointestinal tract (GIT) is inhabited by a dense microbial community of symbionts. Enterococci are among the earliest members of this community and remain core members of the GIT microbiota throughout life. Enterococci have also recently emerged as opportunistic pathogens and major causes of nosocomial infections. Although recognized as a prerequisite for infection, colonization of the GIT by enterococci remains poorly understood. One way that bacteria adapt to dynamic ecosystems like the GIT is through the use of their surface proteins to sense and interact with components of their immediate environment. In Gram-positive bacteria, a subset of surface proteins relies on an enzyme called sortase for covalent attachment to the cell wall. Here, we show that the housekeeping sortase A (SrtA) enzyme promotes intestinal colonization by enterococci. Furthermore, we show that the enzymatic activity of SrtA is key to the ability of Enterococcus faecalis to bind mucin (a major component of the GIT mucus). We also report the GIT colonization phenotypes of E. faecalis mutants lacking selected sortase-dependent proteins (SDPs). Further examination of the mucin binding ability of these mutants suggests that adhesion to mucin contributes to intestinal colonization by E. faecalis.
Collapse
|
13
|
Wójcik M, Eleftheriadis N, Zwinderman MRH, Dömling ASS, Dekker FJ, Boersma YL. Identification of potential antivirulence agents by substitution-oriented screening for inhibitors of Streptococcus pyogenes sortase A. Eur J Med Chem 2018; 161:93-100. [PMID: 30343193 DOI: 10.1016/j.ejmech.2018.10.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 10/02/2018] [Accepted: 10/10/2018] [Indexed: 10/28/2022]
Abstract
Antimicrobial resistance resulting in ineffective treatment of infectious diseases is an increasing global problem, particularly in infections with pathogenic bacteria. In some bacteria, such as Streptococcus pyogenes, the pathogenicity is strongly linked to the attachment of virulence factors. Their attachment to the cellular membrane is a transpeptidation reaction, catalyzed by sortase enzymes. As such, sortases pose an interesting target for the development of new antivirulence strategies that could yield novel antimicrobial drugs. Using the substitution-oriented fragment screening (SOS) approach, we discovered a potent and specific inhibitor (C10) of sortase A from S. pyogenes. The inhibitor C10 showed high specificity towards S. pyogenes sortase A, with an IC50 value of 10 μM and a Kd of 60 μM. We envision that this inhibitor could be employed as a starting point for further exploration of sortase's potential as therapeutic target for antimicrobial drug development.
Collapse
Affiliation(s)
- Magdalena Wójcik
- University of Groningen, Groningen Research Institute of Pharmacy, Department of Chemical and Pharmaceutical Biology, Antonius Deusinglaan 1, 9713 AV, Groningen, the Netherlands.
| | - Nikolaos Eleftheriadis
- University of Groningen, Groningen Research Institute of Pharmacy, Department of Chemical and Pharmaceutical Biology, Antonius Deusinglaan 1, 9713 AV, Groningen, the Netherlands; University of Groningen, Molecular Microscopy Research Group, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG, Groningen, the Netherlands.
| | - Martijn R H Zwinderman
- University of Groningen, Groningen Research Institute of Pharmacy, Department of Chemical and Pharmaceutical Biology, Antonius Deusinglaan 1, 9713 AV, Groningen, the Netherlands.
| | - Alexander S S Dömling
- University of Groningen, Groningen Research Institute of Pharmacy, Department of Drug Design, Antonius Deusinglaan 1, 9713 AV, Groningen, the Netherlands.
| | - Frank J Dekker
- University of Groningen, Groningen Research Institute of Pharmacy, Department of Chemical and Pharmaceutical Biology, Antonius Deusinglaan 1, 9713 AV, Groningen, the Netherlands.
| | - Ykelien L Boersma
- University of Groningen, Groningen Research Institute of Pharmacy, Department of Chemical and Pharmaceutical Biology, Antonius Deusinglaan 1, 9713 AV, Groningen, the Netherlands.
| |
Collapse
|
14
|
van Hensbergen VP, Movert E, de Maat V, Lüchtenborg C, Le Breton Y, Lambeau G, Payré C, Henningham A, Nizet V, van Strijp JAG, Brügger B, Carlsson F, McIver KS, van Sorge NM. Streptococcal Lancefield polysaccharides are critical cell wall determinants for human Group IIA secreted phospholipase A2 to exert its bactericidal effects. PLoS Pathog 2018; 14:e1007348. [PMID: 30321240 PMCID: PMC6201954 DOI: 10.1371/journal.ppat.1007348] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 10/25/2018] [Accepted: 09/20/2018] [Indexed: 12/21/2022] Open
Abstract
Human Group IIA secreted phospholipase A2 (hGIIA) is an acute phase protein with bactericidal activity against Gram-positive bacteria. Infection models in hGIIA transgenic mice have suggested the importance of hGIIA as an innate defense mechanism against the human pathogens Group A Streptococcus (GAS) and Group B Streptococcus (GBS). Compared to other Gram-positive bacteria, GAS is remarkably resistant to hGIIA activity. To identify GAS resistance mechanisms, we exposed a highly saturated GAS M1 transposon library to recombinant hGIIA and compared relative mutant abundance with library input through transposon-sequencing (Tn-seq). Based on transposon prevalence in the output library, we identified nine genes, including dltA and lytR, conferring increased hGIIA susceptibility. In addition, seven genes conferred increased hGIIA resistance, which included two genes, gacH and gacI that are located within the Group A Carbohydrate (GAC) gene cluster. Using GAS 5448 wild-type and the isogenic gacI mutant and gacI-complemented strains, we demonstrate that loss of the GAC N-acetylglucosamine (GlcNAc) side chain in the ΔgacI mutant increases hGIIA resistance approximately 10-fold, a phenotype that is conserved across different GAS serotypes. Increased resistance is associated with delayed penetration of hGIIA through the cell wall. Correspondingly, loss of the Lancefield Group B Carbohydrate (GBC) rendered GBS significantly more resistant to hGIIA-mediated killing. This suggests that the streptococcal Lancefield antigens, which are critical determinants for streptococcal physiology and virulence, are required for the bactericidal enzyme hGIIA to exert its bactericidal function.
Collapse
Affiliation(s)
- Vincent P. van Hensbergen
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Elin Movert
- Department of Experimental Medical Science, Section for Immunology, Lund University, Lund, Sweden
| | - Vincent de Maat
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | | | - Yoann Le Breton
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, MD, United States of America
| | - Gérard Lambeau
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Department of Biochemistry, Valbonne, France
| | - Christine Payré
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Department of Biochemistry, Valbonne, France
| | - Anna Henningham
- Department of Pediatrics and Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America
| | - Victor Nizet
- Department of Pediatrics and Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America
| | - Jos A. G. van Strijp
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Britta Brügger
- Heidelberg University, Biochemistry Center (BZH), Heidelberg, Germany
| | - Fredric Carlsson
- Department of Experimental Medical Science, Section for Immunology, Lund University, Lund, Sweden
- Department of Biology, Section for Molecular Cell Biology, Lund University, Lund, Sweden
| | - Kevin S. McIver
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, MD, United States of America
| | - Nina M. van Sorge
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| |
Collapse
|
15
|
Frost HR, Laho D, Sanderson-Smith ML, Licciardi P, Donath S, Curtis N, Kado J, Dale JB, Steer AC, Smeesters PR. Immune Cross-Opsonization Within emm Clusters Following Group A Streptococcus Skin Infection: Broadening the Scope of Type-Specific Immunity. Clin Infect Dis 2018; 65:1523-1531. [PMID: 29020160 PMCID: PMC7263703 DOI: 10.1093/cid/cix599] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 07/06/2017] [Indexed: 12/13/2022] Open
Abstract
Background Group AStreptococcus (GAS) skin infections are particularly prevalent in developing nations. The GAS M protein, by which strains are differentiated into >220 differentemm types, is immunogenic and elicits protective antibodies. A major obstacle for vaccine development has been the traditional understanding that immunity following infection is restricted to a singleemm type. However, recent evidence has led to the hypothesis of immune cross-reactivity betweenemm types. Methods We investigated the human serological response to GAS impetigo in Fijian schoolchildren, focusing on 3 majoremm clusters (E4, E6, and D4). Pre- and postinfection sera were assayed by enzyme-linked immunosorbent assay with N-terminal M peptides and bactericidal assays using the infecting-type strain,emm cluster–related strains, and nonrelated strains. Results Twenty of the 53 paired sera demonstrated a ≥4-fold increase in antibody titer against the infecting type. When tested against all cluster-related M peptides, we found that 9 of 17 (53%) paired sera had a ≥4-fold increase in antibody titer to cluster-related strains as well. When grouped by cluster, the mean change to cluster-relatedemm types in E4 and E6 was >4-fold (5.9-fold and 19.5-fold, respectively) but for D4 was 3.8-fold. The 17 paired sera were tested in bactericidal assays against selected cluster-related and nonrelated strains. While the responses were highly variable, numerous instances of cross-reactive killing were observed. Conclusions These data demonstrate that M type–specific and cross-reactive immune responses occur following skin infection. The cross-reactive immune responses frequently align withemm clusters, raising new opportunities to design multivalent vaccines with broad coverage.
Collapse
Affiliation(s)
- Hannah R Frost
- Group A Streptococcus Research Group, Murdoch Childrens Research Institute, Melbourne, Australia.,Molecular Bacteriology Laboratory
| | - Delphine Laho
- Group A Streptococcus Research Group, Murdoch Childrens Research Institute, Melbourne, Australia.,Department of Pediatrics, Academic Children Hospital Queen Fabiola, Université Libre de Bruxelles, Brussels, Belgium
| | - Martina L Sanderson-Smith
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong
| | - Paul Licciardi
- Pneumococcal Research Group, Murdoch Childrens Research Institute, Melbourne.,Department of Paediatrics, University of Melbourne, Royal Children's Hospital Melbourne, Parkville, Australia
| | - Susan Donath
- Department of Paediatrics, University of Melbourne, Royal Children's Hospital Melbourne, Parkville, Australia
| | - Nigel Curtis
- Department of Paediatrics, University of Melbourne, Royal Children's Hospital Melbourne, Parkville, Australia
| | - Joseph Kado
- Department of Paediatrics, Colonial War Memorial Hospital.,College of Medicine, Nursing and Health Sciences, Fiji National University.,Fiji Rheumatic Heart Disease Control Program, Suva, Fiji
| | - James B Dale
- Medicine.,Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center.,Department of Veterans Affairs Medical Center, Memphis, Tennessee
| | - Andrew C Steer
- Group A Streptococcus Research Group, Murdoch Childrens Research Institute, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Royal Children's Hospital Melbourne, Parkville, Australia.,Centre for International Child Health, University of Melbourne, Australia
| | - Pierre R Smeesters
- Group A Streptococcus Research Group, Murdoch Childrens Research Institute, Melbourne, Australia.,Molecular Bacteriology Laboratory.,Department of Pediatrics, Academic Children Hospital Queen Fabiola, Université Libre de Bruxelles, Brussels, Belgium.,Centre for International Child Health, University of Melbourne, Australia
| |
Collapse
|
16
|
Abstract
Immunofluorescence microscopy is an invaluable tool for the study of biological processes at the cellular level. While the localization of surface-exposed antigens can easily be determined using fluorescent antibodies, localization of intracellular antigens requires permeabilization of the bacterial cell wall and membrane. Here, we describe an immunofluorescence protocol tailored specifically for Streptococcus pyogenes, applying the phage lysin PlyC for cell wall permeabilization. This protocol allows a high level of morphological preservation, suitable for high-resolution microscopy. With slight modification, this protocol could also be used for other Gram-positive pathogens.
Collapse
|
17
|
Contribution of sortase SrtA2 to Lactobacillus casei BL23 inhibition of Staphylococcus aureus internalization into bovine mammary epithelial cells. PLoS One 2017; 12:e0174060. [PMID: 28323870 PMCID: PMC5360332 DOI: 10.1371/journal.pone.0174060] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 03/02/2017] [Indexed: 11/22/2022] Open
Abstract
Probiotics have been considered as a promising strategy to prevent various diseases in both humans and animals. This approach has gained interest in recent years as a potential means to control bovine mastitis. In a previous study, we found that several L. casei strains, including BL23, were able to inhibit the internalization of S. aureus, a major etiologic agent of mastitis, into bovine mammary epithelial cells (bMEC). This antagonism required a direct contact between L. casei and bMEC or S. aureus, suggesting the inhibition relied on interactions between L. casei cell surface components and bMEC. In this study, we have investigated the impact of some candidates which likely influence bacteria host cell interactions. We have shown that L. casei BL23 fbpA retained its inhibitory potential, indicating that L. casei BL23 antagonism did not rely (solely) on competition between S. aureus and L. casei fibronectin-binding proteins for adhesion to bMEC. We have then investigated the impact of four sortase mutants, srtA1, srtA2, srtC1 and srtC2, and a double mutant (srtA1-srtA2) on L. casei BL23 inhibitory potential. Sortases are responsible for the anchoring on the bacterial cell wall of LPXTG-proteins, which reportedly play an important role in bacteria-host cell interaction. All the srt mutants tested presented a reduced inhibition capacity, the most pronounced effect being observed with the srtA2 mutant. A lower internalization capacity of L. casei srtA2 into bMEC was also observed. This was associated with several changes at the surface of L. casei BL23 srtA2 compared to the wild type (wt) strain, including altered abundance of some LPXTG- and moonlighting proteins, and modifications of cell wall structure. These results strongly support the role of sortase A2 in L. casei BL23 inhibition against S. aureus internalization. Deciphering the contribution of the cell surface components altered in srtA2 strain in the inhibition will require further investigation.
Collapse
|
18
|
Bhatty M, Camacho MI, Gonzalez-Rivera C, Frank KL, Dale JL, Manias DA, Dunny GM, Christie PJ. PrgU: a suppressor of sex pheromone toxicity in Enterococcus faecalis. Mol Microbiol 2016; 103:398-412. [PMID: 27785854 DOI: 10.1111/mmi.13563] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Upon sensing of the peptide pheromone cCF10, Enterococcus faecalis cells carrying pCF10 produce three surface adhesins (PrgA, PrgB or Aggregation Substance, PrgC) and the Prg/Pcf type IV secretion system and, in turn, conjugatively transfer the plasmid at high frequencies to recipient cells. Here, we report that cCF10 induction is highly toxic to cells sustaining a deletion of prgU, a small orf located immediately downstream of prgB on pCF10. Upon pheromone exposure, these cells overproduce the Prg adhesins and display impaired envelope integrity, as evidenced by antibiotic susceptibility, misplaced division septa and cell lysis. Compensatory mutations in regulatory loci controlling expression of pCF10-encoded prg/pcf genes, or constitutive PrgU overproduction, block production of the Prg adhesins and render cells insensitive to pheromone. Cells engineered to overproduce PrgB, even independently of other pCF10-encoded proteins, have severely compromised cell envelopes and strong growth defects. PrgU has an RNA-binding fold, and prgB-prgU gene pairs are widely distributed among E. faecalis isolates and other enterococcal and staphylococcal species. Together, our findings support a model in which PrgU proteins represent a novel class of RNA-binding regulators that act to mitigate toxicity accompanying overproduction of PrgB-like adhesins in E. faecalis and other clinically-important Gram-positive species.
Collapse
Affiliation(s)
- Minny Bhatty
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, Texas, 77030, USA
| | - Martha I Camacho
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, Texas, 77030, USA
| | - Christian Gonzalez-Rivera
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, Texas, 77030, USA
| | - Kristi L Frank
- Department of Microbiology and Immunology, University of Minnesota Medical School, Microbiology Research Facility, 689 23rd Ave, S.E, Minneapolis, Minnesota, 55455, USA
| | - Jennifer L Dale
- Department of Microbiology and Immunology, University of Minnesota Medical School, Microbiology Research Facility, 689 23rd Ave, S.E, Minneapolis, Minnesota, 55455, USA
| | - Dawn A Manias
- Department of Microbiology and Immunology, University of Minnesota Medical School, Microbiology Research Facility, 689 23rd Ave, S.E, Minneapolis, Minnesota, 55455, USA
| | - Gary M Dunny
- Department of Microbiology and Immunology, University of Minnesota Medical School, Microbiology Research Facility, 689 23rd Ave, S.E, Minneapolis, Minnesota, 55455, USA
| | - Peter J Christie
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, Texas, 77030, USA
| |
Collapse
|