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Zhu X, Wang S, Du Y, Liang Z, Yao H, Chen X, Wu Z. A novel aquaporin Aagp contributes to Streptococcus suis H 2O 2 efflux and virulence. Virulence 2023; 14:2249789. [PMID: 37621097 PMCID: PMC10461500 DOI: 10.1080/21505594.2023.2249789] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 07/05/2023] [Accepted: 08/13/2023] [Indexed: 08/26/2023] Open
Abstract
Streptococcus suis is a bacterium that can cause infections in pigs and humans. Although oxidative stress is common occurrence during bacterial growth and infection, the regulation networks of S. suis under oxidative stress remain poorly understood. To address this, we utilized RNA-Seq to reveal the transcriptional landscape of S. suis in response to H2O2 stress. We identified novel genes responsible for S. suis resistance to oxidative stress, including those involved in DNA repair or protection, and essential for the biosynthesis of amino acids and nucleic acids. In addition, we found that a novel aquaporin, Aagp, belonging to atypical aquaglyceroporins and widely distributed in diverse S. suis serotypes, plays a crucial role during H2O2 stress. By performing oxidative stress assays and measuring the intracellular H2O2 concentrations of the wild-type strain and Aagp mutants during H2O2 stress, we found that Aagp facilitated H2O2 efflux. Additionally, we found that Aagp might be involved in glycerol transport, as shown by the growth inhibition and H2O2 production in the presence of glycerol. Mice infection experiments indicated that Aagp contributed to S. suis virulence. This study contributes to understanding the mechanism of S. suis oxidative stress response, S. suis pathogenesis, and the function of aquaporins in prokaryotes.
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Affiliation(s)
- Xinchi Zhu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
| | - Shuoyue Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
| | - Yu Du
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
| | - Zijing Liang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
| | - Huochun Yao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
| | - Xiang Chen
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, China
| | - Zongfu Wu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
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Three Distinct Proteases Are Responsible for Overall Cell Surface Proteolysis in Streptococcus thermophilus. Appl Environ Microbiol 2021; 87:e0129221. [PMID: 34550764 DOI: 10.1128/aem.01292-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The lactic acid bacterium Streptococcus thermophilus was believed to display only two distinct proteases at the cell surface, namely, the cell envelope protease PrtS and the housekeeping protease HtrA. Using peptidomics, we demonstrate here the existence of an additional active cell surface protease, which shares significant homology with the SepM protease of Streptococcus mutans. Although all three proteases-PrtS, HtrA, and SepM-are involved in the turnover of surface proteins, they demonstrate distinct substrate specificities. In particular, SepM cleaves proteins involved in cell wall metabolism and cell elongation, and its inactivation has consequences for cell morphology. When all three proteases are inactivated, the residual cell-surface proteolysis of S. thermophilus is approximately 5% of that of the wild-type strain. IMPORTANCE Streptococcus thermophilus is a lactic acid bacterium used widely as a starter in the dairy industry. Due to its "generally recognized as safe" status and its weak cell surface proteolytic activity, it is also considered a potential bacterial vector for heterologous protein production. Our identification of a new cell surface protease made it possible to construct a mutant strain with a 95% reduction in surface proteolysis, which could be useful in numerous biotechnological applications.
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Campeau A, Uchiyama S, Sanchez C, Sauceda C, Nizet V, Gonzalez DJ. The S Protein of Group B Streptococcus Is a Critical Virulence Determinant That Impacts the Cell Surface Virulome. Front Microbiol 2021; 12:729308. [PMID: 34721327 PMCID: PMC8551713 DOI: 10.3389/fmicb.2021.729308] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 09/13/2021] [Indexed: 11/14/2022] Open
Abstract
Group B Streptococcus (GBS, S. agalactiae) is a human commensal and occasional pathogen that remains a leading cause of neonatal sepsis and meningitis with increasing disease burden in adult populations. Although programs for universal screening in pregnancy to guide intrapartum prophylaxis have reduced GBS invasive disease burden resulting from mother-to-newborn transfer during birth, better knowledge of disease mechanisms may elucidate new strategies to reduce antibiotic exposure. In our efforts to expand the knowledge base required for targeted anti-virulence therapies, we identified a GBS homolog for a recently identified virulence determinant of group A Streptococcus, S protein, and evaluated its role in GBS pathogenesis. A GBS S protein deletion mutant, Δess, showed altered cell-surface properties compared to the WT parent strain, including defective retention of its surface polysaccharide. Quantitative proteome analysis of enzymatically shaved surface epitopes of the GBS Δess mutant revealed a dysregulated cell surface virulome, with reduced abundance of several protein and glycoprotein components. The Δess mutant showed markedly attenuated virulence in a murine model of GBS systemic infection, with increased proteasome activity detected in the spleens of animals infected with the Δess mutant. These results expand the key roles S protein plays in streptococcal pathogenesis and introduces a new GBS virulence determinant and potential target for therapy development.
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Affiliation(s)
- Anaamika Campeau
- Department of Pharmacology, University of California San Diego, La Jolla, CA, United States.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, United States.,Center for Microbiome Innovation, University of California San Diego, La Jolla, CA, United States
| | - Satoshi Uchiyama
- Department of Pediatrics, University of California San Diego, La Jolla, CA, United States
| | - Concepcion Sanchez
- Department of Pharmacology, University of California San Diego, La Jolla, CA, United States.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, United States.,Center for Microbiome Innovation, University of California San Diego, La Jolla, CA, United States
| | - Consuelo Sauceda
- Department of Pharmacology, University of California San Diego, La Jolla, CA, United States.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, United States.,Center for Microbiome Innovation, University of California San Diego, La Jolla, CA, United States
| | - Victor Nizet
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, United States.,Center for Microbiome Innovation, University of California San Diego, La Jolla, CA, United States.,Department of Pediatrics, University of California San Diego, La Jolla, CA, United States
| | - David J Gonzalez
- Department of Pharmacology, University of California San Diego, La Jolla, CA, United States.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, United States.,Center for Microbiome Innovation, University of California San Diego, La Jolla, CA, United States
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Sanduja P, Gupta M, Somani VK, Yadav V, Dua M, Hanski E, Sharma A, Bhatnagar R, Johri AK. Cross-serotype protection against group A Streptococcal infections induced by immunization with SPy_2191. Nat Commun 2020; 11:3545. [PMID: 32669564 PMCID: PMC7363907 DOI: 10.1038/s41467-020-17299-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 06/23/2020] [Indexed: 12/22/2022] Open
Abstract
Group A Streptococcus (GAS) infection causes a range of diseases, but vaccine development is hampered by the high number of serotypes. Here, using reverse vaccinology the authors identify SPy_2191 as a cross-protective vaccine candidate. From 18 initially identified surface proteins, only SPy_2191 is conserved, surface-exposed and inhibits both GAS adhesion and invasion. SPy_2191 immunization in mice generates bactericidal antibodies resulting in opsonophagocytic killing of prevalent and invasive GAS serotypes of different geographical regions, including M1 and M49 (India), M3.1 (Israel), M1 (UK) and M1 (USA). Resident splenocytes show higher interferon-γ and tumor necrosis factor-α secretion upon antigen re-stimulation, suggesting activation of cell-mediated immunity. SPy_2191 immunization significantly reduces streptococcal load in the organs and confers ~76-92% protection upon challenge with invasive GAS serotypes. Further, it significantly suppresses GAS pharyngeal colonization in mice mucosal infection model. Our findings suggest that SPy_2191 can act as a universal vaccine candidate against GAS infections.
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Affiliation(s)
- Pooja Sanduja
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
- Division of Infectious Diseases, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Manish Gupta
- BSL-3 Unit, Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Vikas Kumar Somani
- BSL-3 Unit, Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India
- Division of Oncology, Washington University School of Medicine, St. Louis, MO, USA
| | - Vikas Yadav
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Meenakshi Dua
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Emanuel Hanski
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research-Israel-Canada(IMRIC), Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Abhinay Sharma
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research-Israel-Canada(IMRIC), Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | | | - Atul Kumar Johri
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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Abstract
Streptococcus agalactiae (group B Streptococcus, GBS), is a Gram-positive, asymptomatic colonizer of the human gastrointestinal tract and vaginal tract of 10 - 30% of adults. In immune-compromised individuals, including neonates, pregnant women, and the elderly, GBS may switch to an invasive pathogen causing sepsis, arthritis, pneumonia, and meningitis. Because GBS is a leading bacterial pathogen of neonates, current prophylaxis is comprised of late gestation screening for GBS vaginal colonization and subsequent peripartum antibiotic treatment of GBS-positive mothers. Heavy GBS vaginal burden is a risk factor for both neonatal disease and colonization. Unfortunately, little is known about the host and bacterial factors that promote or permit GBS vaginal colonization. This protocol describes a technique for establishing persistent GBS vaginal colonization using a single β-estradiol pre-treatment and daily sampling to determine bacterial load. It further details methods to administer additional therapies or reagents of interest and to collect vaginal lavage fluid and reproductive tract tissues. This mouse model will further the understanding of the GBS-host interaction within the vaginal environment, which will lead to potential therapeutic targets to control maternal vaginal colonization during pregnancy and to prevent transmission to the vulnerable newborn. It will also be of interest to increase our understanding of general bacterial-host interactions in the female vaginal tract.
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Affiliation(s)
- Kathryn A Patras
- Department of Pediatrics, Division of Host-Microbe Systems & Therapeutics, University of California San Diego School of Medicine
| | - Kelly S Doran
- Department of Pediatrics, Division of Host-Microbe Systems & Therapeutics, University of California San Diego School of Medicine; Department of Biology and Center for Microbial Sciences, San Diego State University;
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Abstract
We are rapidly returning to a world in which bacterial infections are a major health issue. Pathogenic bacteria are able to colonize and cause pathology due to the possession of virulence factors such as adhesins, invasins, evasins and toxins. These are generally specifically evolved proteins with selective actions. It is, therefore, surprising that most human bacterial pathogens employ moonlighting proteins as virulence factors. Currently, >90 bacterial species employ one or more moonlighting protein families to aid colonization and induce disease. These organisms employ 90 moonlighting bacterial protein families and these include enzymes of the glycolytic pathway, tricarboxylic acid (TCA) cycle, hexosemonophosphate shunt, glyoxylate cycle and a range of other metabolic enzymes, proteases, transporters and, also, molecular chaperones and protein-folding catalysts. These proteins have homologues in eukaryotes and only a proportion of the moonlighting proteins employed are solely bacterial in origin. Bacterial moonlighting proteins can be divided into those with single moonlighting functions and those with multiple additional biological actions. These proteins contribute significantly to the population of virulence factors employed by bacteria and some are obvious therapeutic targets. Where examined, bacterial moonlighting proteins bind to target ligands with high affinity. A major puzzle is the evolutionary mechanism(s) responsible for bacterial protein moonlighting and a growing number of highly homologous bacterial moonlighting proteins exhibit widely different moonlighting actions, suggesting a lack in our understanding of the mechanism of evolution of protein active sites.
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Lemire P, Roy D, Fittipaldi N, Okura M, Takamatsu D, Bergman E, Segura M. Implication of TLR- but not of NOD2-signaling pathways in dendritic cell activation by group B Streptococcus serotypes III and V. PLoS One 2014; 9:e113940. [PMID: 25436906 PMCID: PMC4250082 DOI: 10.1371/journal.pone.0113940] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 10/31/2014] [Indexed: 12/31/2022] Open
Abstract
Group B Streptococcus (GBS) is an important agent of life-threatening invasive infection. It has been previously shown that encapsulated type III GBS is easily internalized by dendritic cells (DCs), and that this internalization had an impact on cytokine production. The receptors underlying these processes are poorly characterized. Knowledge on the mechanisms used by type V GBS to activate DCs is minimal. In this work, we investigated the role of Toll-like receptor (TLR)/MyD88 signaling pathway, the particular involvement of TLR2, and that of the intracellular sensing receptor NOD2 in the activation of DCs by types III and V GBS. The role of capsular polysaccharide (CPS, one of the most important GBS virulence factors) in bacterial-DC interactions was evaluated using non-encapsulated mutants. Despite differences in the role of CPS between types III and V GBS in bacterial internalization and intracellular survival, no major differences were observed in their capacity to modulate release of cytokines by DC. For both serotypes, CPS had a minor role in this response. Production of cytokines by DCs was shown to strongly rely on MyD88-dependent signaling pathways, suggesting that DCs recognize GBS and become activated mostly through TLR signaling. Yet, GBS-infected TLR2-/- DCs only showed a partial reduction in the production of IL-6 and CXCL1 compared to control DCs. Surprisingly, CXCL10 release by type III or type V GBS-infected DCs was MyD88-independent. No differences in DC activation were observed between NOD2-/- and control DCs. These results demonstrate the involvement of various receptors and the complexity of the cytokine production pathways activated by GBS upon DC infection.
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Affiliation(s)
- Paul Lemire
- Laboratory of Immunology, Faculty of Veterinary Medicine, University of Montreal, St-Hyacinthe, Quebec, Canada
| | - David Roy
- Laboratory of Immunology, Faculty of Veterinary Medicine, University of Montreal, St-Hyacinthe, Quebec, Canada
| | - Nahuel Fittipaldi
- Public Health Ontario, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Masatoshi Okura
- Bacterial and Parasitic Diseases Research Division, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan
| | - Daisuke Takamatsu
- Bacterial and Parasitic Diseases Research Division, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan
- The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Eugenia Bergman
- Laboratory of Immunology, Faculty of Veterinary Medicine, University of Montreal, St-Hyacinthe, Quebec, Canada
| | - Mariela Segura
- Laboratory of Immunology, Faculty of Veterinary Medicine, University of Montreal, St-Hyacinthe, Quebec, Canada
- * E-mail:
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Papasergi S, Galbo R, Lanza-Cariccio V, Domina M, Signorino G, Biondo C, Pernice I, Poyart C, Trieu-Cuot P, Teti G, Beninati C. Analysis of the Streptococcus agalactiae exoproteome. J Proteomics 2013; 89:154-64. [PMID: 23770297 DOI: 10.1016/j.jprot.2013.06.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 05/13/2013] [Accepted: 06/02/2013] [Indexed: 10/26/2022]
Abstract
UNLABELLED The two-component regulatory system CovRS is the main regulator of virulence gene expression in Group B Streptococcus (GBS), the leading cause of invasive infections in neonates. In this study we analyzed by mass spectrometry the GBS extracellular protein complex (i.e. the exoproteome) of NEM316 wild-type (WT) strain and its isogenic covRS deletion mutant (ΔcovRS). A total of 53 proteins, 49 of which had classical secretion signals, were identified: 12 were released by both strains while 21 and 20 were released exclusively by WT and ΔcovRS strains, respectively. In addition to known surface proteins, we detected here unstudied cell-wall associated proteins and/or orthologs of putative virulence factors present in other pathogenic streptococci. While the functional role of these proteins remains to be elucidated, our data suggest that the analysis of the exoproteome of bacterial pathogens under different gene expression conditions may be a powerful tool for the rapid identification of novel virulence factors and vaccine candidates. BIOLOGICAL SIGNIFICANCE We believe that this manuscript will be of interest to Journal of Proteomics readers since the paper describes the identification of several putative virulence factors and vaccine candidates of the group B streptococcus, an important pathogen, using a simple proteomics strategy involving LC-MS analysis of culture supernatants obtained from two strains with divergent gene expression patterns. This technique provided the most comprehensive inventory of extracellular proteins obtained from a single streptococcal species thus far. The approach described has the added benefit of being easily applicable to a large number of different strains, making it ideal for the identification of conserved vaccine candidates.
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Sharma A, Arya DK, Sagar V, Bergmann R, Chhatwal GS, Johri AK. Identification of potential universal vaccine candidates against group A Streptococcus by using high throughput in silico and proteomics approach. J Proteome Res 2012. [PMID: 23181284 DOI: 10.1021/pr3005265] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Streptococcus pyogenes or group A Streptococcus (GAS) causes ~700 million human infections each year, resulting in over 500,000 deaths. The development of a commercial GAS vaccine is hampered due to high strain and serotype diversity in different geographical regions, and the generation of cross-reactive antibodies that may induce autoimmune disease. There is an urgent need to search for alternative vaccine candidates. High throughput multigenome data mining coupled with proteomics seems to be a promising approach to identify the universal vaccine candidates. In the present study, in silico analysis led to prediction of 147 proteins as universal vaccine candidates. Distribution pattern of these predicted candidates was explored in nonsequenced Indian GAS strains (n = 20) by using DNA array hybridization validating in silico analysis. High throughput analyses of surface proteins using 1D-SDS-PAGE coupled with ESI-LC-MS/MS was applied on highly (M49) and less (M1) invasive GAS strains of Indian origin. Comparative proteomics analysis revealed that highly invasive GAS M49 had metabolically more active membrane associated protein machinery than less invasive M1. Further, by overlapping proteomics data with in silico predicted vaccine candidate genes, 52 proteins were identified as probable universal vaccine candidates, which were expressed in these GAS serotypes. These proteins can further be investigated as universal vaccine candidates against GAS. Moreover, this robust approach may serve as a model that can be applied to identify the universal vaccine candidates in case of other pathogenic bacteria with high strain and genetic diversity.
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Affiliation(s)
- Abhinay Sharma
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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10
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Sharma P, Lata H, Arya DK, Kashyap AK, Kumar H, Dua M, Ali A, Johri AK. Role of pilus proteins in adherence and invasion of Streptococcus agalactiae to the lung and cervical epithelial cells. J Biol Chem 2012; 288:4023-34. [PMID: 23209289 DOI: 10.1074/jbc.m112.425728] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Streptococcus agalactiae, or group B Streptococcus (GBS), is an important opportunistic pathogen that causes pneumonia, sepsis, and meningitis in neonates and severe diseases in immunocompromised adults. We have performed comparative genomics of prevalent GBS serotypes of Indian origin (i.e. Ia, III, V, and VII). Pilus-proteins were commonly found up-regulated, and their expression was studied by using antiserum for GBS80 (backbone protein of pilus island-I), GBS67 (ancillary protein of PI-2a), and SAN1518 (backbone protein of PI-2b) by whole cell and Western blot analysis. To check the role of pilus proteins in adherence and invasion, an inhibition assay was performed. Comparative immunoblotting experiments revealed that expression of pili proteins does not differ in geographically different selected serotypes, Ia and V, of India and the United States. In the case of A549 cells, we found that GBS VII invasion and adherence was inhibited by pilus protein-specific antiserum SAN1518 significantly (p < 0.001) by 88.5 and 91%, respectively. We found that mutant strains, deficient in the pilus proteins (Δgbs80 and Δsan1518) exhibit a significant decrease in adherence in the case of type Ia, III, and VII. In the case of type VII, we have found a 95% reduction in invasion when Δsan1518 was used with A549 cells. Because the pilus proteins were identified previously as vaccine candidates against GBS serotypes of developed countries, we also found their role in the attachment and invasion of GBS of Indian origin. Thus, the present work supports the idea of making a more effective pilus protein-based vaccine that can be used universally.
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Affiliation(s)
- Puja Sharma
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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CsrRS and environmental pH regulate group B streptococcus adherence to human epithelial cells and extracellular matrix. Infect Immun 2012; 80:3975-84. [PMID: 22949550 DOI: 10.1128/iai.00699-12] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Streptococcus agalactiae (group B Streptococcus or GBS) is a common colonizer of the gastrointestinal and genital tracts and an important cause of invasive infections in newborn infants and in adults with predisposing chronic conditions or advanced age. Attachment to epithelial surfaces at mucosal sites is a critical step in the successful colonization of a human host, and regulation of this process is likely to play an important role in both commensalism and dissemination to cause invasive disease. We found that inactivation of the CsrRS (or CovRS) two-component system increased GBS adherence to epithelial cells derived from human vaginal, cervical, and respiratory epithelium, as well as increasing adherence to extracellular matrix proteins and increasing biofilm formation on polystyrene. Neutral (as opposed to acidic) pH enhanced GBS binding to vaginal epithelial cells and to fibrinogen and fibronectin, effects that were partially dependent on CsrRS. The regulatory effects of CsrRS and environmental pH on bacterial adherence correlated with their effects on the expression of multiple surface adhesins, as assessed by quantitative reverse transcription-PCR. We conclude that GBS adherence to epithelial and abiotic surfaces is regulated by the CsrRS two-component system and by environmental pH through their regulatory effects on the expression of bacterial surface adhesins. Dynamic regulation of GBS adherence enhances the organism's adaptability to survival in multiple niches in the human host.
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12
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Florindo C, Ferreira R, Borges V, Spellerberg B, Gomes J, Borrego M. Selection of reference genes for real-time expression studies in Streptococcus agalactiae. J Microbiol Methods 2012; 90:220-7. [DOI: 10.1016/j.mimet.2012.05.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 05/15/2012] [Accepted: 05/18/2012] [Indexed: 10/28/2022]
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A proteomic investigation of Streptococcus agalactiae reveals that human serum induces the C protein β antigen and arginine deiminase. Microbes Infect 2011; 13:757-60. [PMID: 21458589 DOI: 10.1016/j.micinf.2011.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 02/18/2011] [Accepted: 03/24/2011] [Indexed: 11/22/2022]
Abstract
Streptococcus agalactiae is a major neonatal pathogen. Disease progression is characterised by bacterial adaptation from commensal maternal vaginal colonisation to environments associated with neonatal disease, including exposure to blood. To explore this adaptation in vitro, we have used proteomics to identify proteins differentially expressed following growth on Todd Hewitt agar in the presence or absence of 10% v/v human serum. Twelve differentially expressed proteins were identified. Notably, the C protein β antigen and arginine deiminase proteins were upregulated following growth in the presence of human serum, consistent with previous studies implicating these two proteins in the pathogenesis of S. agalactiae disease.
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Bull AT. The renaissance of continuous culture in the post-genomics age. J Ind Microbiol Biotechnol 2010; 37:993-1021. [PMID: 20835748 DOI: 10.1007/s10295-010-0816-4] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 08/11/2010] [Indexed: 01/08/2023]
Abstract
The development of continuous culture techniques 60 years ago and the subsequent formulation of theory and the diversification of experimental systems revolutionised microbiology and heralded a unique period of innovative research. Then, progressively, molecular biology and thence genomics and related high-information-density omics technologies took centre stage and microbial growth physiology in general faded from educational programmes and research funding priorities alike. However, there has been a gathering appreciation over the past decade that if the claims of systems biology are going to be realised, they will have to be based on rigorously controlled and reproducible microbial and cell growth platforms. This revival of continuous culture will be long lasting because its recognition as the growth system of choice is firmly established. The purpose of this review, therefore, is to remind microbiologists, particularly those new to continuous culture approaches, of the legacy of what I call the first age of continuous culture, and to explore a selection of researches that are using these techniques in this post-genomics age. The review looks at the impact of continuous culture across a comprehensive range of microbiological research and development. The ability to establish (quasi-) steady state conditions is a frequently stated advantage of continuous cultures thereby allowing environmental parameters to be manipulated without causing concomitant changes in the specific growth rate. However, the use of continuous cultures also enables the critical study of specified transition states and chemical, physical or biological perturbations. Such dynamic analyses enhance our understanding of microbial ecology and microbial pathology for example, and offer a wider scope for innovative drug discovery; they also can inform the optimization of batch and fed-batch operations that are characterized by sequential transitions states.
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Affiliation(s)
- Alan T Bull
- School of Biosciences, University of Kent, Canterbury, Kent CT27NJ, UK.
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Soriani M, Telford JL. Relevance of pili in pathogenic streptococci pathogenesis and vaccine development. Future Microbiol 2010; 5:735-47. [PMID: 20441546 DOI: 10.2217/fmb.10.37] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A common mechanism used by bacteria to initiate adhesion to host tissues during colonization is the expression of long filamentous structures extending from their surface. These structures, known as pili or fimbriae, were initially identified in Gram-negative bacteria, and are typically formed by noncovalent interactions between pilin subunits. Pili have only recently been described in Gram-positive bacteria. In particular, in pathogenic streptococci the proteinaceous components of pili are covalently polymerized by the action of sortase enzymes similar to those involved in the covalent attachment of Gram-positive surface proteins to the peptidoglycan cell wall. With great relevance to the development of strategies to combat Gram-positive-associated infections, pilus components from pathogenic streptococci have been shown to induce protective immunity in mouse models of streptococcal disease. In addition, recent papers have created new perspectives on the role of such organelles in streptococcal pathogenesis, from the involvement in colonization and biofilm formation to translocation of tissue barriers. All this information makes the characterization of pili a hot scientific issue that we believe will lead to important future developments in understanding bacterial dynamics that lead to successful occupation of microbial niches.
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Affiliation(s)
- Marco Soriani
- Microbial Molecular Biology Department, Novartis Vaccines, Via Fiorentina 1, 53100 Siena, Italy
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Yang Q, Zhang M, Harrington DJ, Black GW, Sutcliffe IC. A proteomic investigation of Streptococcus agalactiae grown under conditions associated with neonatal exposure reveals the upregulation of the putative virulence factor C protein β antigen. Int J Med Microbiol 2010; 300:331-7. [DOI: 10.1016/j.ijmm.2010.01.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Revised: 11/30/2009] [Accepted: 01/06/2010] [Indexed: 12/14/2022] Open
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Margarit I, Bonacci S, Pietrocola G, Rindi S, Ghezzo C, Bombaci M, Nardi-Dei V, Grifantini R, Speziale P, Grandi G. Capturing host-pathogen interactions by protein microarrays: identification of novel streptococcal proteins binding to human fibronectin, fibrinogen, and C4BP. FASEB J 2009; 23:3100-12. [PMID: 19417080 DOI: 10.1096/fj.09-131458] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Microbial pathogen entry and survival in the host is mediated by a network of molecular interactions between the two partners, which has been the subject of many research efforts. A complex picture is emerging in which host-pathogen crosstalk involves a high number of proteins, often with redundant functions. In the present study, we investigated the potential of protein microarrays to simultaneously scan interactions between surface proteins from two main human streptococcal pathogens, Streptococcus pyogenes and Streptococcus agalactiae, and three human ligands, fibronectin, fibrinogen, and C4 binding protein, known to play an important role in streptococcal pathogenesis. By using this technology, we confirmed interactions described in the literature and detected a novel set of streptococcal proteins with binding capacities for the human ligands. The observations were validated by Western blot and ELISA techniques. Three of the newly identified proteins were isoforms of a group B streptococcus-secreted component named Fib and displayed differential binding capacities for fibronectin, fibrinogen, and C4BP. The protein regions involved in the interaction with each ligand were identified by constructing fragments of one of the Fib variants. The approach proved valuable for the acquisition of novel insights into the complex network of protein-protein interactions occurring during microbial infection.
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Bray BA, Sutcliffe IC, Harrington DJ. Impact of lgt mutation on lipoprotein biosynthesis and in vitro phenotypes of Streptococcus agalactiae. MICROBIOLOGY-SGM 2009; 155:1451-1458. [PMID: 19383708 DOI: 10.1099/mic.0.025213-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Although Streptococcus agalactiae, the group B Streptococcus, is a leading cause of invasive neonatal disease worldwide the molecular basis of its virulence is still poorly understood. To investigate the role of lipoproteins in the physiology and interaction of this pathogen with host cells, we generated a mutant S. agalactiae strain (A909DeltaLgt) deficient in the Lgt enzyme and thus unable to lipidate lipoprotein precursors (pro-lipoproteins). The loss of pro-lipoprotein lipidation did not affect the viability of S. agalactiae or its growth in several different media, including cation-depleted media. The processing of two well-characterized lipoproteins, but not a non-lipoprotein, was clearly shown to be aberrant in A909DeltaLgt. The mutant strain was shown to be more sensitive to oxidative stress in vitro although the molecular basis of this increased sensitivity was not apparent. The inactivation of Lgt also resulted in changes to the bacterial cell envelope, as demonstrated by reduced retention of both the group B carbohydrate and the polysaccharide capsule and a statistically significant reduction (P=0.0079) in A909DeltaLgt adherence to human endothelial cells of fetal origin. These data confirm that failure to process lipoproteins correctly has pleiotropic effects that may be of significance to S. agalactiae colonization and pathogenesis.
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Rajagopal L. Understanding the regulation of Group B Streptococcal virulence factors. Future Microbiol 2009; 4:201-21. [PMID: 19257847 DOI: 10.2217/17460913.4.2.201] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Bacterial infections remain a significant threat to the health of newborns and adults. Group B Streptococci (GBS) are Gram-positive bacteria that are common asymptomatic colonizers of healthy adults. However, this opportunistic organism can also subvert suboptimal host defenses to cause severe invasive disease and tissue damage. The increasing emergence of antibiotic-resistant GBS raises more concerns for sustained measures in treatment of the disease. A number of factors that are important for virulence of GBS have been identified. This review summarizes the functions of some well-characterized virulence factors, with an emphasis on how GBS regulates their expression. Regulatory and signaling molecules are attractive drug targets in the treatment of bacterial infections. Consequently, understanding signaling responses of GBS is essential for elucidation of pathogenesis of GBS infection and for the identification of novel therapeutic agents.
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Affiliation(s)
- Lakshmi Rajagopal
- Department of Pediatric Infectious Diseases, University of Washington & Seattle Children's Hospital Research Institute, 1900 Ninth Avenue, Seattle, WA 98101-91304, USA.
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Sitkiewicz I, Musser JM. Analysis of growth-phase regulated genes in Streptococcus agalactiae by global transcript profiling. BMC Microbiol 2009; 9:32. [PMID: 19208240 PMCID: PMC2660347 DOI: 10.1186/1471-2180-9-32] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Accepted: 02/10/2009] [Indexed: 01/04/2023] Open
Abstract
Background Bacteria employ multiple mechanisms to control gene expression and react to their constantly changing environment. Bacterial growth in rich laboratory medium is a dynamic process in which bacteria utilize nutrients from simple to complex and change physical properties of the medium, as pH, during the process. To determine which genes are differentially expressed throughout growth from mid log to stationary phase, we performed global transcript analysis. Results The S. agalactiae transcriptome is dynamic in response to growth conditions. Several genes and regulons involved in virulence factor production and utilization of alternate carbon sources were differentially expressed throughout growth. Conclusion These data provide new information about the magnitude of plasticity of the S. agalactiae transcriptome and its adaptive response to changing environmental conditions. The resulting information will greatly assist investigators studying S. agalactiae physiology and pathogenesis.
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Affiliation(s)
- Izabela Sitkiewicz
- Center for Molecular and Translational Human Infectious Diseases Research, The Methodist Hospital Research Institute, Houston, Texas 77030, USA.
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Margarit I, Rinaudo CD, Galeotti CL, Maione D, Ghezzo C, Buttazzoni E, Rosini R, Runci Y, Mora M, Buccato S, Pagani M, Tresoldi E, Berardi A, Creti R, Baker CJ, Telford JL, Grandi G. Preventing bacterial infections with pilus-based vaccines: the group B streptococcus paradigm. J Infect Dis 2009; 199:108-115. [PMID: 19086816 DOI: 10.1086/595564] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/18/2023] Open
Abstract
We recently described the presence of 3 pilus variants in the human pathogen group B streptococcus (GBS; also known as Streptococcus agalactiae), each encoded by a distinct pathogenicity island, as well as the ability of pilus components to elicit protection in mice against homologous challenge. To determine whether a vaccine containing a combination of proteins from the 3 pilus types could provide broad protection, we analyzed pili distribution and conservation in 289 clinical isolates. We found that pilus sequences in each island are conserved, all strains carried at least 1 of the 3 islands, and a combination of the 3 pilus components conferred protection against all tested GBS challenge strains. These data are the first to indicate that a vaccine exclusively constituted by pilus components can be effective in preventing infections caused by GBS, and they pave the way for the use of a similar approach against other pathogenic streptococci.
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Bryan JD, Liles R, Cvek U, Trutschl M, Shelver D. Global transcriptional profiling reveals Streptococcus agalactiae genes controlled by the MtaR transcription factor. BMC Genomics 2008; 9:607. [PMID: 19087320 PMCID: PMC2627894 DOI: 10.1186/1471-2164-9-607] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Accepted: 12/16/2008] [Indexed: 12/03/2022] Open
Abstract
Background Streptococcus agalactiae (group B Streptococcus; GBS) is a significant bacterial pathogen of neonates and an emerging pathogen of adults. Though transcriptional regulators are abundantly encoded on the GBS genome, their role in GBS pathogenesis is poorly understood. The mtaR gene encodes a putative LysR-type transcriptional regulator that is critical for the full virulence of GBS. Previous studies have shown that an mtaR- mutant transports methionine at reduced rates and grows poorly in normal human plasma not supplemented with methionine. The decreased virulence of the mtaR mutant was correlated with a methionine transport defect; however, no MtaR-regulated genes were identified. Results Microarray analysis of wild-type GBS and an mtaR mutant revealed differential expression of 12 genes, including 1 upregulated and 11 downregulated genes in the mtaR mutant. Among the downregulated genes, we identified a cluster of cotranscribed genes encoding a putative methionine transporter (metQ1NP) and peptidase (pdsM). The expression of four genes potentially involved in arginine transport (artPQ) and arginine biosynthesis (argGH) was downregulated and these genes localized to two transcriptional units. The virulence factor cspA, which encodes an extracellular protease, was downregulated. Additionally, the SAN_1255 locus, which putatively encodes a protein displaying similarity to plasminogen activators, was downregulated. Conclusion To our knowledge, this is the first study to describe the global influence of MtaR on GBS gene expression. This study implicates the metQ1NP genes as encoding the MtaR-regulated methionine transporter, which may provide a mechanistic explanation for the methionine-dependent growth defect of the mtaR mutant. In addition to modulating the expression of genes involved in metabolism and amino acid transport, inactivation of mtaR affected the expression of other GBS genes implicated in pathogenesis. These findings suggest the possibility that MtaR may play a multifaceted role in GBS pathogenesis by regulating the expression of numerous genes.
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Affiliation(s)
- Joshua D Bryan
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center in Shreveport, Shreveport, Louisiana 71130, USA.
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Mereghetti L, Sitkiewicz I, Green NM, Musser JM. Extensive adaptive changes occur in the transcriptome of Streptococcus agalactiae (group B streptococcus) in response to incubation with human blood. PLoS One 2008; 3:e3143. [PMID: 18769548 PMCID: PMC2519835 DOI: 10.1371/journal.pone.0003143] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Accepted: 08/14/2008] [Indexed: 11/19/2022] Open
Abstract
To enhance understanding of how Streptococcus agalactiae (group B streptococcus, GBS) adapts during invasive infection, we performed a whole-genome transcriptome analysis after incubation with whole human blood. Global changes occurred in the GBS transcriptome rapidly in response to blood contact following shift from growth in a rich laboratory medium. Most (83%) of the significantly altered transcripts were down-regulated after 30 minutes of incubation in blood, and all functional categories of genes were abundantly represented. We observed complex dynamic changes in the expression of transcriptional regulators and stress response genes that allow GBS to rapidly adapt to blood. The transcripts of relatively few proven virulence genes were up-regulated during the first 90 minutes. However, a key discovery was that genes encoding proteins involved in interaction with the host coagulation/fibrinolysis system and bacterial-host interactions were rapidly up-regulated. Extensive transcript changes also occurred for genes involved in carbohydrate metabolism, including multi-functional proteins and regulators putatively involved in pathogenesis. Finally, we discovered that an incubation temperature closer to that occurring in patients with severe infection and high fever (40°C) induced additional differences in the GBS transcriptome relative to normal body temperature (37°C). Taken together, the data provide extensive new information about transcriptional adaptation of GBS exposed to human blood, a crucial step during GBS pathogenesis in invasive diseases, and identify many new leads for molecular pathogenesis research.
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Affiliation(s)
- Laurent Mereghetti
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology, The Methodist Hospital Research Institute, Houston, Texas, United States of America
- Université François-Rabelais, Faculté de Médecine, EA3854 “Bactéries et risque materno-foetal”, et Centre Hospitalier Universitaire, Tours, France
| | - Izabela Sitkiewicz
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology, The Methodist Hospital Research Institute, Houston, Texas, United States of America
| | - Nicole M. Green
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology, The Methodist Hospital Research Institute, Houston, Texas, United States of America
| | - James M. Musser
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology, The Methodist Hospital Research Institute, Houston, Texas, United States of America
- * E-mail:
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An amino acid substitution in PBP-3 in Haemophilus influenzae associate with the invasion to bronchial epithelial cells. Microbiol Res 2008; 165:11-20. [PMID: 18417334 DOI: 10.1016/j.micres.2008.03.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 02/15/2008] [Accepted: 03/01/2008] [Indexed: 11/23/2022]
Abstract
Haemophilus influenzae is a common pathogen of respiratory infections. We examined whether beta-lactamase-negative ampicillin-resistant (BLNAR) strains that are known to have ampicillin resistance due to a substitution of amino acid of penicillin binding protein (PBP)-3, differ from beta-lactamase-negative ampicillin-susceptible strains with regard to invasion of bronchial epithelium. After 3h incubation of each of 34 beta-lactamase-negative ampicillin-susceptible and 57 BLNAR strains in the presence of BEAS-2B cells, a human bronchial epithelium cell line, extracellular bacteria were killed using gentamicin and intracellular bacteria numbered. All nine strains in which the efficiency of invasion was 1% or higher were BLNAR strains. The rate of invasion was significantly greater in strains with PBP-3 amino acid substitution (Met377 to Ile, Ser385 to Thr, Leu389 to Phe, and Asn526 to Lys) (n=34) than in those with no amino acid substitution. Electron microscopy showed that high invasive BLNAR strains were observed in cytoplasm of BEAS-2B cell layer. The injured cells were 9.44+/-1.76% among attaching cells examined by trypan blue staining after 6h. These data may suggest that the amino acid substitution of the PBP in BLNAR strains may at least partly play roles in macropinocytosis, leading to the invasion and injury to epithelial cells.
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