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Williams E, Seib KL, Fairley CK, Pollock GL, Hocking JS, McCarthy JS, Williamson DA. Neisseria gonorrhoeae vaccines: a contemporary overview. Clin Microbiol Rev 2024; 37:e0009423. [PMID: 38226640 PMCID: PMC10938898 DOI: 10.1128/cmr.00094-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024] Open
Abstract
Neisseria gonorrhoeae infection is an important public health issue, with an annual global incidence of 87 million. N. gonorrhoeae infection causes significant morbidity and can have serious long-term impacts on reproductive and neonatal health and may rarely cause life-threatening disease. Global rates of N. gonorrhoeae infection have increased over the past 20 years. Importantly, rates of antimicrobial resistance to key antimicrobials also continue to increase, with the United States Centers for Disease Control and Prevention identifying drug-resistant N. gonorrhoeae as an urgent threat to public health. This review summarizes the current evidence for N. gonorrhoeae vaccines, including historical clinical trials, key N. gonorrhoeae vaccine preclinical studies, and studies of the impact of Neisseria meningitidis vaccines on N. gonorrhoeae infection. A comprehensive survey of potential vaccine antigens, including those identified through traditional vaccine immunogenicity approaches, as well as those identified using more contemporary reverse vaccinology approaches, are also described. Finally, the potential epidemiological impacts of a N. gonorrhoeae vaccine and research priorities for further vaccine development are described.
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Affiliation(s)
- Eloise Williams
- Department of Infectious Diseases, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
- Victorian Infectious Diseases Reference Laboratory at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Kate L. Seib
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Christopher K. Fairley
- Melbourne Sexual Health Centre, Alfred Health, Melbourne, Victoria, Australia
- Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Georgina L. Pollock
- Department of Infectious Diseases, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Jane S. Hocking
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
| | - James S. McCarthy
- Department of Infectious Diseases, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Victorian Infectious Diseases Service, Royal Melbourne Hospital at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Deborah A. Williamson
- Department of Infectious Diseases, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
- Victorian Infectious Diseases Reference Laboratory at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
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Potter AD, Criss AK. Dinner date: Neisseria gonorrhoeae central carbon metabolism and pathogenesis. Emerg Top Life Sci 2024; 8:15-28. [PMID: 37144661 PMCID: PMC10625648 DOI: 10.1042/etls20220111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/10/2023] [Accepted: 04/14/2023] [Indexed: 05/06/2023]
Abstract
Neisseria gonorrhoeae, the causative agent of the sexually transmitted infection gonorrhea, is a human-adapted pathogen that does not productively infect other organisms. The ongoing relationship between N. gonorrhoeae and the human host is facilitated by the exchange of nutrient resources that allow for N. gonorrhoeae growth in the human genital tract. What N. gonorrhoeae 'eats' and the pathways used to consume these nutrients have been a topic of investigation over the last 50 years. More recent investigations are uncovering the impact of N. gonorrhoeae metabolism on infection and inflammatory responses, the environmental influences driving N. gonorrhoeae metabolism, and the metabolic adaptations enabling antimicrobial resistance. This mini-review is an introduction to the field of N. gonorrhoeae central carbon metabolism in the context of pathogenesis. It summarizes the foundational work used to characterize N. gonorrhoeae central metabolic pathways and the effects of these pathways on disease outcomes, and highlights some of the most recent advances and themes under current investigation. This review ends with a brief description of the current outlook and technologies under development to increase understanding of how the pathogenic potential of N. gonorrhoeae is enabled by metabolic adaptation.
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Affiliation(s)
- Aimee D. Potter
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA USA
| | - Alison K. Criss
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA USA
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Albdrawy AI, Aleanizy FS, Eltayb EK, Aldossari AA, Alanazi MM, Alfaraj R, Eltahir E, Albasri HM, Alanazi JS, Alqahtani FY. Effect of C7-3-Peptide-Loaded Chitosan Nanoparticles Against Multi-Drug-Resistant Neisseria gonorrhoeae. Int J Nanomedicine 2024; 19:609-631. [PMID: 38264736 PMCID: PMC10804975 DOI: 10.2147/ijn.s445737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 01/09/2024] [Indexed: 01/25/2024] Open
Abstract
Introduction The emergence of Neisseria gonorrhoeae-resistant strains represents one of the most urgent global threats. In this regard, C7-3 peptide is one of the anti-virulence therapies that has demonstrated promising anti-gonococcal activity. Accordingly, this research aimed to formulate C7-3 peptide and its derivatives in chitosan nanoparticles. Methods The peptide loaded chitosan nanoparticles were prepared using ion gelation method, and their physicochemical characteristics were investigated. The anti-gonococcal and antibiofilm activity of prepared NPs was assessed, and their cytotoxicity in human ovarian cells was evaluated. Results All prepared NPs were optimized for the smallest particle size of 136.9 to 168.3 nm. The EE% of C7-3, C7-3m1, and C7-3m2 CNPs reached 90.2, 92.5, and 91.8%, respectively. An in vitro release study demonstrated a continuous sustained-release pattern of C7-3 peptide from NPs. The SDS-PAGE assay confirmed the integrity of C7-3 peptide after the fabrication process. When comparing each peptide alone, the generated NPs demonstrated higher anti-gonococcal and anti-biofilm effectiveness against standard and resistant bacterial strains under anaerobic conditions. The cytotoxicity experiments revealed the cytocompatibility of NPs in HeLa cell lines. Given the advantages of enhanced anti-gonococcal activity of the C7-3 peptide and its derivatives when loaded with CNPs, as well as the antimicrobial properties of chitosan NPs, the reported NPs have great potential in the treatment of gonococcal infection.
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Affiliation(s)
- Asma Ismail Albdrawy
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Fadilah Sfouq Aleanizy
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Esraa Kamal Eltayb
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Abdullah A Aldossari
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Mohammed M Alanazi
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Rihaf Alfaraj
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Eram Eltahir
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Hibah M Albasri
- Department of Biology, College of Science, Taibah University, Madinah, Saudi Arabia
| | - Jouri S Alanazi
- Pharmaceutical Care Department, National Guard Health Affairs, Riyadh, Saudi Arabia
| | - Fulwah Yahya Alqahtani
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
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Barreiro DS, Oliveira RNS, Pauleta SR. Biochemical Characterization of the Copper Nitrite Reductase from Neisseria gonorrhoeae. Biomolecules 2023; 13:1215. [PMID: 37627281 PMCID: PMC10452240 DOI: 10.3390/biom13081215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 07/16/2023] [Accepted: 08/02/2023] [Indexed: 08/27/2023] Open
Abstract
The copper-containing nitrite reductase from Neisseria gonorrhoeae has been shown to play a critical role in the infection mechanism of this microorganism by producing NO and abolishing epithelial exfoliation. This enzyme is a trimer with a type 1 copper center per subunit and a type 2 copper center in the subunits interface, with the latter being the catalytic site. The two centers were characterized for the first time by EPR and CD spectroscopy, showing that the type 1 copper center has a high rhombicity due to its lower symmetry and more tetragonal structure, while the type 2 copper center has the usual properties, but with a smaller hyperfine coupling constant (A// = 10.5 mT). The thermostability of the enzyme was analyzed by differential scanning calorimetry, which shows a single endothermic transition in the thermogram, with a maximum at 94 °C, while the CD spectra in the visible region indicate the presence of the type 1 copper center up to 80 °C. The reoxidation of the N. gonorrhoeae copper-containing nitrite reductase in the presence of nitrite were analyzed by visible spectroscopy and showed a pH dependence, being higher at pH 5.5-6.0. The high thermostability of this enzyme may be important to maintaining a high activity in the extracellular space and to making it less susceptible to denaturation and proteolysis, contributing to the proliferation of N. gonorrhoeae.
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Affiliation(s)
- Daniela S. Barreiro
- Microbial Stress Lab, UCIBIO—Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
- Associate Laboratory i4HB—Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
| | - Ricardo N. S. Oliveira
- Microbial Stress Lab, UCIBIO—Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
- Associate Laboratory i4HB—Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
| | - Sofia R. Pauleta
- Microbial Stress Lab, UCIBIO—Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
- Associate Laboratory i4HB—Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
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Tzeng YL, Sannigrahi S, Berman Z, Bourne E, Edwards JL, Bazan JA, Turner AN, Moir JWB, Stephens DS. Acquisition of Gonococcal AniA-NorB Pathway by the Neisseria meningitidis Urethritis Clade Confers Denitrifying and Microaerobic Respiration Advantages for Urogenital Adaptation. Infect Immun 2023; 91:e0007923. [PMID: 37092998 PMCID: PMC10187123 DOI: 10.1128/iai.00079-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 03/28/2023] [Indexed: 04/25/2023] Open
Abstract
Neisseria meningitidis historically has been an infrequent and sporadic cause of urethritis and other urogenital infections. However, a nonencapsulated meningococcal clade belonging to the hyperinvasive clonal complex 11.2 lineage has recently emerged and caused clusters of urethritis cases in the United States and other countries. One of the genetic signatures of the emerging N. meningitidis urethritis clade (NmUC) is a chromosomal gene conversion event resulting in the acquisition of the Neisseria gonorrhoeae denitrification apparatus-the N. gonorrhoeae alleles encoding the nitrite reductase AniA, the nitric oxide (NO) reductase NorB, and the intergenic promoter region. The biological importance of the N. gonorrhoeae AniA-NorB for adaptation of the NmUC to a new environmental niche is investigated herein. We found that oxygen consumption, nitrite utilization, and NO production were significantly altered by the conversion event, resulting in different denitrifying aerobic and microaerobic growth of the clade. Further, transcription of aniA and norB in NmUC isolates differed from canonical N. meningitidis, and important polymorphisms within the intergenic region, which influenced aniA promoter activity of the NmUC, were identified. The contributions of three known meningococcal regulators (NsrR, FNR, and NarQP) in controlling the denitrification pathway and endogenous NO metabolism were distinct. Overall, transcription of aniA was dampened relative to canonical N. meningitidis, and this correlated with the lower NO accumulation in the clade. Denitrification and microaerobic respiration were bolstered, and protection against host-derived NO was likely enhanced. The acquisition of the N. gonorrhoeae denitrification pathway by the NmUC supports the clade's adaptation and survival in a microaerobic urogenital environment.
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Affiliation(s)
- Yih-Ling Tzeng
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Soma Sannigrahi
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Zachary Berman
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Emily Bourne
- Department of Biology, University of York, Heslington, York, United Kingdom
| | - Jennifer L. Edwards
- Department of Pediatrics, The Research Institute at Nationwide Children’s Hospital and The Ohio State University, Columbus, Ohio, USA
| | - Jose A. Bazan
- Division of Infectious Diseases, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio, USA
- Sexual Health Clinic, Columbus Public Health, Columbus, Ohio, USA
| | - Abigail Norris Turner
- Division of Infectious Diseases, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - James W. B. Moir
- Department of Biology, University of York, Heslington, York, United Kingdom
| | - David S. Stephens
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
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Sunkavalli A, McClure R, Genco C. Molecular Regulatory Mechanisms Drive Emergent Pathogenetic Properties of Neisseria gonorrhoeae. Microorganisms 2022; 10:922. [PMID: 35630366 PMCID: PMC9147433 DOI: 10.3390/microorganisms10050922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/25/2022] [Accepted: 04/26/2022] [Indexed: 12/05/2022] Open
Abstract
Neisseria gonorrhoeae is the causative agent of the sexually transmitted infection (STI) gonorrhea, with an estimated 87 million annual cases worldwide. N. gonorrhoeae predominantly colonizes the male and female genital tract (FGT). In the FGT, N. gonorrhoeae confronts fluctuating levels of nutrients and oxidative and non-oxidative antimicrobial defenses of the immune system, as well as the resident microbiome. One mechanism utilized by N. gonorrhoeae to adapt to this dynamic FGT niche is to modulate gene expression primarily through DNA-binding transcriptional regulators. Here, we describe the major N. gonorrhoeae transcriptional regulators, genes under their control, and how these regulatory processes lead to pathogenic properties of N. gonorrhoeae during natural infection. We also discuss the current knowledge of the structure, function, and diversity of the FGT microbiome and its influence on gonococcal survival and transcriptional responses orchestrated by its DNA-binding regulators. We conclude with recent multi-omics data and modeling tools and their application to FGT microbiome dynamics. Understanding the strategies utilized by N. gonorrhoeae to regulate gene expression and their impact on the emergent characteristics of this pathogen during infection has the potential to identify new effective strategies to both treat and prevent gonorrhea.
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Affiliation(s)
- Ashwini Sunkavalli
- Department of Immunology, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111, USA;
| | - Ryan McClure
- Pacific Northwest National Laboratory, Richland, WA 99354, USA;
| | - Caroline Genco
- Department of Immunology, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111, USA;
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Abstract
Neisseria gonorrhoeae is an obligate human pathogen that is the cause of the sexually transmitted disease gonorrhoea. Recently, there has been a surge in gonorrhoea cases that has been exacerbated by the rapid rise in gonococcal multidrug resistance to all useful antimicrobials resulting in this organism becoming a significant public health burden. Therefore, there is a clear and present need to understand the organism's biology through its physiology and pathogenesis to help develop new intervention strategies. The gonococcus initially colonises and adheres to host mucosal surfaces utilising a type IV pilus that helps with microcolony formation. Other adhesion strategies include the porin, PorB, and the phase variable outer membrane protein Opa. The gonococcus is able to subvert complement mediated killing and opsonisation by sialylation of its lipooligosaccharide and deploys a series of anti-phagocytic mechanisms. N. gonorrhoeae is a fastidious organism that is able to grow on a limited number of primary carbon sources such as glucose and lactate. The utilization of lactate by the gonococcus has been implicated in a number of pathogenicity mechanisms. The bacterium lives mainly in microaerobic environments and can grow both aerobically and anaerobically with the aid of nitrite. The gonococcus does not produce siderophores for scavenging iron but can utilize some produced by other bacteria, and it is able to successful chelate iron from host haem, transferrin and lactoferrin. The gonococcus is an incredibly versatile human pathogen; in the following chapter, we detail the intricate mechanisms used by the bacterium to invade and survive within the host.
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Affiliation(s)
- Luke R Green
- Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Joby Cole
- Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Ernesto Feliz Diaz Parga
- Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Jonathan G Shaw
- Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom.
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Lim KYL, Mullally CA, Haese EC, Kibble EA, McCluskey NR, Mikucki EC, Thai VC, Stubbs KA, Sarkar-Tyson M, Kahler CM. Anti-Virulence Therapeutic Approaches for Neisseria gonorrhoeae. Antibiotics (Basel) 2021; 10:antibiotics10020103. [PMID: 33494538 PMCID: PMC7911339 DOI: 10.3390/antibiotics10020103] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 01/15/2023] Open
Abstract
While antimicrobial resistance (AMR) is seen in both Neisseria gonorrhoeae and Neisseria meningitidis, the former has become resistant to commonly available over-the-counter antibiotic treatments. It is imperative then to develop new therapies that combat current AMR isolates whilst also circumventing the pathways leading to the development of AMR. This review highlights the growing research interest in developing anti-virulence therapies (AVTs) which are directed towards inhibiting virulence factors to prevent infection. By targeting virulence factors that are not essential for gonococcal survival, it is hypothesized that this will impart a smaller selective pressure for the emergence of resistance in the pathogen and in the microbiome, thus avoiding AMR development to the anti-infective. This review summates the current basis of numerous anti-virulence strategies being explored for N. gonorrhoeae.
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Affiliation(s)
- Katherine Y. L. Lim
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Christopher A. Mullally
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Ethan C. Haese
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Emily A. Kibble
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150, Australia
| | - Nicolie R. McCluskey
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150, Australia
| | - Edward C. Mikucki
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Van C. Thai
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Keith A. Stubbs
- School of Molecular Sciences, University of Western Australia, Crawley, WA 6009, Australia;
| | - Mitali Sarkar-Tyson
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Charlene M. Kahler
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
- Correspondence:
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Muenzner P, Hauck CR. Neisseria gonorrhoeae Blocks Epithelial Exfoliation by Nitric-Oxide-Mediated Metabolic Cross Talk to Promote Colonization in Mice. Cell Host Microbe 2020; 27:793-808.e5. [PMID: 32289262 DOI: 10.1016/j.chom.2020.03.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 12/19/2019] [Accepted: 03/17/2020] [Indexed: 12/18/2022]
Abstract
Several pathogens suppress exfoliation, a key defense of epithelia against microbial colonization. Common among these pathogens, exemplified by Neisseria gonorrhoeae, is their ability to bind carcinoembryonic antigen-related cell adhesion molecules (CEACAMs). Gonococcal CEACAM engagement triggers the expression of CD105, which is necessary to block epithelial exfoliation, whereas homotypic CEACAM-CEACAM interactions or antibody-mediated CEACAM clustering does not lead to CD105 expression. Here, we show that CEACAM-associated bacteria release nitric oxide (NO) during anaerobic respiration, and membrane-permeable NO initiates a eukaryotic signaling pathway involving soluble guanylate cyclase (sGC), protein kinase G, and the transcription factor CREB to upregulate CD105 expression. A murine vaginal infection model with N. gonorrhoeae reveals this metabolic cross communication allows bacterial suppression of epithelial exfoliation to facilitate mucosal colonization. Disrupting NO-initiated responses in host cells re-establishes epithelial exfoliation and inhibits mouse genital tract colonization by N. gonorrhoeae, suggesting a host-directed approach to prevent bacterial infections.
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Affiliation(s)
- Petra Muenzner
- Lehrstuhl Für Zellbiologie, Fachbereich Biologie, Universität Konstanz, 78457 Konstanz, Germany
| | - Christof R Hauck
- Lehrstuhl Für Zellbiologie, Fachbereich Biologie, Universität Konstanz, 78457 Konstanz, Germany; Konstanz Research School Chemical Biology, Universität Konstanz, 78457 Konstanz, Germany.
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Baarda BI, Zielke RA, Jerse AE, Sikora AE. Lipid-Modified Azurin of Neisseria gonorrhoeae Is Not Surface Exposed and Does Not Interact With the Nitrite Reductase AniA. Front Microbiol 2018; 9:2915. [PMID: 30538694 PMCID: PMC6277709 DOI: 10.3389/fmicb.2018.02915] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 11/13/2018] [Indexed: 12/20/2022] Open
Abstract
Lipid-modified cupredoxin azurin (Laz) is involved in electron transport in Neisseria and proposed to act as an electron donor to the surface-displayed nitrite reductase AniA. We identified Laz in Neisseria gonorrhoeae cell envelopes and naturally elaborated membrane vesicles in proteomic investigations focused on discovering new vaccine and therapeutic targets for this increasingly difficult to treat pathogen. Its surface exposure in N. meningitidis suggested Laz could be a vaccine candidate for N. gonorrhoeae. Here we characterized the localization, expression, and role of Laz within the gonococcal cell envelope and challenged the hypothesis that Laz and AniA interact. While we demonstrate that Laz indeed shows some good features of a vaccine antigen, such as stable expression, high conservation, and ability to elicit antibodies that cross-react with a diverse panel of Neisseria, it is not a surface-displayed lipoprotein in the gonococcus. This discovery eliminates Laz as a gonorrhea vaccine candidate, further highlighting the necessity of examining homologous protein localization between closely related species. Absence of Laz slightly altered cell envelope integrity but was not associated with growth defects in vitro, including during anoxia, implicating the presence of other electron pathways to AniA. To further dissect the implied AniA-Laz interaction, we utilized biolayer interferometry and optimized and executed chemical cross-linking coupled with immunoblotting to covalently link interacting protein partners in living gonococci. This method, applied for the first time in N. gonorrhoeae research to interrogate protein complexes, was validated by the appearance of the trimer form of AniA, as well as by increased formation of the β-barrel assembly machinery complex, in the presence of cross-linker. We conclude that Laz is not an electron donor to AniA based on their distinct subcellular localization, discordant expression during infection of the female mouse lower genital tract, and lack of interaction in vivo and in vitro.
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Affiliation(s)
- Benjamin I Baarda
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, OR, United States
| | - Ryszard A Zielke
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, OR, United States
| | - Ann E Jerse
- Department of Microbiology and Immunology, F. Edward Hebert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Aleksandra E Sikora
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, OR, United States.,Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, OR, United States
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11
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Shewell LK, Jen FEC, Jennings MP. Refinement of immunizing antigens to produce functional blocking antibodies against the AniA nitrite reductase of Neisseria gonorrhoeae. PLoS One 2017; 12:e0182555. [PMID: 28771632 PMCID: PMC5542605 DOI: 10.1371/journal.pone.0182555] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 07/20/2017] [Indexed: 01/16/2023] Open
Abstract
The emergence of multi-drug resistant Neisseria gonorrhoeae has generated an urgent need for novel therapies or a vaccine to prevent gonococcal disease. In this study we investigate the potential of targeting the surface exposed nitrite reductase, AniA, to block activity by producing functional blocking antibodies. AniA activity is essential for anaerobic growth and biofilm formation of N. gonorrhoeae and functional blocking antibodies may prevent colonisation and disease. Seven peptides covering regions adjacent to the active site were designed based on the AniA structure. Six of the seven peptide conjugates generated immune responses. Peptide 7, GALGQLKVEGAEN, was able to elicit antibodies capable of blocking AniA activity. Antiserum raised against the peptide 7 conjugate detected AniA in 20 N. gonorrhoeae clinical isolates. Recombinant AniA protein antigens were also assessed in this study and generated high-titre, functional blocking antibody responses. Peptide 7 conjugates or truncated recombinant AniA antigens have potential for inclusion in a vaccine against N. gonorrhoeae.
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Affiliation(s)
- Lucy K. Shewell
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Freda E.-C Jen
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Michael P. Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
- * E-mail:
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12
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Peptide Inhibitors Targeting the Neisseria gonorrhoeae Pivotal Anaerobic Respiration Factor AniA. Antimicrob Agents Chemother 2017; 61:AAC.00186-17. [PMID: 28584144 DOI: 10.1128/aac.00186-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 05/27/2017] [Indexed: 12/24/2022] Open
Abstract
Neisseria gonorrhoeae causes the sexually transmitted infection gonorrhea, which is highly prevalent worldwide and has a major impact on reproductive and neonatal health. The superbug status of N. gonorrhoeae necessitates the development of drugs with different mechanisms of action. Here, we focused on targeting the nitrite reductase AniA, which is a pivotal component of N. gonorrhoeae anaerobic respiration and biofilm formation. Our studies showed that gonococci expressing AniA containing the altered catalytic residues D137A and H280A failed to grow under anaerobic conditions, demonstrating that the nitrite reductase function is essential. To facilitate the pharmacological targeting of AniA, new crystal structures of AniA were refined to 1.90-Å and 2.35-Å resolutions, and a phage display approach with libraries expressing randomized linear dodecameric peptides or heptameric peptides flanked by a pair of cysteine residues was utilized. Biopanning experiments led to the identification of 29 unique peptides, with 1 of them, C7-3, being identified multiple times. Evaluation of their ability to interact with AniA using enzyme-linked immunosorbent assay and computational docking studies revealed that C7-3 was the most promising inhibitor, binding near the type 2 copper site of the enzyme, which is responsible for interaction with nitrite. Subsequent enzymatic assays and biolayer interferometry with a synthetic C7-3 and its derivatives, C7-3m1 and C7-3m2, demonstrated potent inhibition of AniA. Finally, the MIC50 value of C7-3 and C7-3m2 against anaerobically grown N. gonorrhoeae was 0.6 mM. We present the first peptide inhibitors of AniA, an enzyme that should be further exploited for antigonococcal drug development.
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13
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Tanwer P, Bauer S, Heinrichs E, Panda G, Saluja D, Rudel T, Beier D. Post-transcriptional regulation of target genes by the sRNA FnrS in Neisseria gonorrhoeae. MICROBIOLOGY-SGM 2017; 163:1081-1092. [PMID: 28691898 DOI: 10.1099/mic.0.000484] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Small non-coding RNAs (sRNAs) are well-established post-transcriptional regulators of gene expression in bacteria that respond to a variety of environmental stimuli. They usually act by base-pairing with their target mRNAs, which is commonly facilitated by the RNA chaperone Hfq. In this study we initiated the analysis of the sRNA FnrS of Neisseria gonorrhoeae, which is induced under anaerobic conditions. We identified four putative FnrS target genes using bioinformatics approaches and validated these target genes using translational reporter gene fusions in both Escherichia coli and N. gonorrhoeae, thereby demonstrating their downregulation by direct base-pairing between the respective mRNA and FnrS. We demonstrate deregulation of target mRNAs upon deletion of fnrS and provide evidence that the isc gene cluster required for iron-sulfur cluster biosynthesis, which harbours iscS, which is a direct target of FnrS, is coordinately downregulated by the sRNA. By mutational analysis we show that, surprisingly, three distinct regions of FnrS are employed for interaction with different target genes.
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Affiliation(s)
- Pooja Tanwer
- Chair of Microbiology, University of Würzburg, Biocenter, Germany.,Dr B R Ambedkar Center for Biomedical Research, University of Delhi, India
| | - Susanne Bauer
- Chair of Microbiology, University of Würzburg, Biocenter, Germany
| | | | - Gurudutta Panda
- Institute of Network Biology (INET), Helmholtz Zentrum München, Germany
| | - Daman Saluja
- Dr B R Ambedkar Center for Biomedical Research, University of Delhi, India
| | - Thomas Rudel
- Chair of Microbiology, University of Würzburg, Biocenter, Germany
| | - Dagmar Beier
- Chair of Microbiology, University of Würzburg, Biocenter, Germany
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14
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Emergence of a new Neisseria meningitidis clonal complex 11 lineage 11.2 clade as an effective urogenital pathogen. Proc Natl Acad Sci U S A 2017; 114:4237-4242. [PMID: 28373547 DOI: 10.1073/pnas.1620971114] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Neisseria meningitidis (Nm) clonal complex 11 (cc11) lineage is a hypervirulent pathogen responsible for outbreaks of invasive meningococcal disease, including among men who have sex with men, and is increasingly associated with urogenital infections. Recently, clusters of Nm urethritis have emerged primarily among heterosexual males in the United States. We determined that nonencapsulated meningococcal isolates from an ongoing Nm urethritis outbreak among epidemiologically unrelated men in Columbus, Ohio, are linked to increased Nm urethritis cases in multiple US cities, including Atlanta and Indianapolis, and that they form a unique clade (the US Nm urethritis clade, US_NmUC). The isolates belonged to the cc11 lineage 11.2/ET-15 with fine type of PorA P1.5-1, 10-8; FetA F3-6; PorB 2-2 and express a unique FHbp allele. A common molecular fingerprint of US_NmUC isolates was an IS1301 element in the intergenic region separating the capsule ctr-css operons and adjacent deletion of cssA/B/C and a part of csc, encoding the serogroup C capsule polymerase. This resulted in the loss of encapsulation and intrinsic lipooligosaccharide sialylation that may promote adherence to mucosal surfaces. Furthermore, we detected an IS1301-mediated inversion of an ∼20-kb sequence near the cps locus. Surprisingly, these isolates had acquired by gene conversion the complete gonococcal denitrification norB-aniA gene cassette, and strains grow well anaerobically. The cc11 US_NmUC isolates causing urethritis clusters in the United States may have adapted to a urogenital environment by loss of capsule and gene conversion of the Neisseria gonorrheae norB-aniA cassette promoting anaerobic growth.
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15
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Edwards JL, Jennings MP, Apicella MA, Seib KL. Is gonococcal disease preventable? The importance of understanding immunity and pathogenesis in vaccine development. Crit Rev Microbiol 2016; 42:928-41. [PMID: 26805040 PMCID: PMC4958600 DOI: 10.3109/1040841x.2015.1105782] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/01/2015] [Accepted: 10/06/2015] [Indexed: 12/31/2022]
Abstract
Gonorrhea is a major, global public health problem for which there is no vaccine. The continuing emergence of antibiotic-resistant strains raises concerns that untreatable Neisseria gonorrhoeae may become widespread in the near future. Consequently, there is an urgent need for increased efforts towards the development of new anti-gonococcal therapeutics and vaccines, as well as suitable models for potential pre-clinical vaccine trials. Several current issues regarding gonorrhea are discussed herein, including the global burden of disease, the emergence of antibiotic-resistance, the status of vaccine development and, in particular, a focus on the model systems available to evaluate drug and vaccine candidates. Finally, alternative approaches to evaluate vaccine candidates are presented. Such approaches may provide valuable insights into the protective mechanisms, and correlates of protection, required to prevent gonococcal transmission, local infection and disease sequelae.
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Affiliation(s)
- Jennifer L. Edwards
- Department of Pediatrics, The Research Institute at Nationwide Children's Hospital and The Ohio State UniversityColumbus,
OH,
USA
| | | | | | - Kate L. Seib
- Institute for Glycomics, Griffith University,
Gold Coast,
Australia
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16
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Characterization of the Neisseria gonorrhoeae Iron and Fur Regulatory Network. J Bacteriol 2016; 198:2180-91. [PMID: 27246574 DOI: 10.1128/jb.00166-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 05/24/2016] [Indexed: 01/05/2023] Open
Abstract
UNLABELLED The Neisseria gonorrhoeae ferric uptake regulator (Fur) protein controls expression of iron homeostasis genes in response to intracellular iron levels. In this study, using transcriptome sequencing (RNA-seq) analysis of an N. gonorrhoeae fur strain, we defined the gonococcal Fur and iron regulons and characterized Fur-controlled expression of an ArsR-like DNA binding protein. We observed that 158 genes (8% of the genome) showed differential expression in response to iron in an N. gonorrhoeae wild-type or fur strain, while 54 genes exhibited differential expression in response to Fur. The Fur regulon was extended to additional regulators, including NrrF and 13 other small RNAs (sRNAs), and two transcriptional factors. One transcriptional factor, coding for an ArsR-like regulator (ArsR), exhibited increased expression under iron-replete conditions in the wild-type strain but showed decreased expression across iron conditions in the fur strain, an effect that was reversed in a fur-complemented strain. Fur was shown to bind to the promoter region of the arsR gene downstream of a predicted σ(70) promoter region. Electrophoretic mobility shift assay (EMSA) analysis confirmed binding of the ArsR protein to the norB promoter region, and sequence analysis identified two additional putative targets, NGO1411 and NGO1646. A gonococcal arsR strain demonstrated decreased survival in human endocervical epithelial cells compared to that of the wild-type and arsR-complemented strains, suggesting that the ArsR regulon includes genes required for survival in host cells. Collectively, these results demonstrate that the N. gonorrhoeae Fur functions as a global regulatory protein to repress or activate expression of a large repertoire of genes, including additional transcriptional regulatory proteins. IMPORTANCE Gene regulation in bacteria in response to environmental stimuli, including iron, is of paramount importance to both bacterial replication and, in the case of pathogenic bacteria, successful infection. Bacterial DNA binding proteins are a common mechanism utilized by pathogens to control gene expression under various environmental conditions. Here, we show that the DNA binding protein Fur, expressed by the human pathogen Neisseria gonorrhoeae, controls the expression of a large repertoire of genes and extends this regulon by controlling expression of additional DNA binding proteins. One of these proteins, an ArsR-like regulator, was required for N. gonorrhoeae survival within host cells. These results show that the Fur regulon extends to additional regulatory proteins, which together contribute to gonococcal mechanisms of pathogenesis.
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17
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Zielke RA, Wierzbicki IH, Baarda BI, Gafken PR, Soge OO, Holmes KK, Jerse AE, Unemo M, Sikora AE. Proteomics-driven Antigen Discovery for Development of Vaccines Against Gonorrhea. Mol Cell Proteomics 2016; 15:2338-55. [PMID: 27141096 PMCID: PMC4937508 DOI: 10.1074/mcp.m116.058800] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 04/25/2016] [Indexed: 12/18/2022] Open
Abstract
Expanding efforts to develop preventive gonorrhea vaccines is critical because of the dire possibility of untreatable gonococcal infections. Reverse vaccinology, which includes genome and proteome mining, has proven very successful in the discovery of vaccine candidates against many pathogenic bacteria. However, progress with this approach for a gonorrhea vaccine remains in its infancy. Accordingly, we applied a comprehensive proteomic platform-isobaric tagging for absolute quantification coupled with two-dimensional liquid chromatography and mass spectrometry-to identify potential gonococcal vaccine antigens. Our previous analyses focused on cell envelopes and naturally released membrane vesicles derived from four different Neisseria gonorrhoeae strains. Here, we extended these studies to identify cell envelope proteins of N. gonorrhoeae that are ubiquitously expressed and specifically induced by physiologically relevant environmental stimuli: oxygen availability, iron deprivation, and the presence of human serum. Together, these studies enabled the identification of numerous potential gonorrhea vaccine targets. Initial characterization of five novel vaccine candidate antigens that were ubiquitously expressed under these different growth conditions demonstrated that homologs of BamA (NGO1801), LptD (NGO1715), and TamA (NGO1956), and two uncharacterized proteins, NGO2054 and NGO2139, were surface exposed, secreted via naturally released membrane vesicles, and elicited bactericidal antibodies that cross-reacted with a panel of temporally and geographically diverse isolates. In addition, analysis of polymorphisms at the nucleotide and amino acid levels showed that these vaccine candidates are highly conserved among N. gonorrhoeae strains. Finally, depletion of BamA caused a loss of N. gonorrhoeae viability, suggesting it may be an essential target. Together, our data strongly support the use of proteomics-driven discovery of potential vaccine targets as a sound approach for identifying promising gonococcal antigens.
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Affiliation(s)
- Ryszard A Zielke
- From the ‡Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, Oregon
| | - Igor H Wierzbicki
- From the ‡Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, Oregon
| | - Benjamin I Baarda
- From the ‡Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, Oregon
| | - Philip R Gafken
- §Proteomics Facility, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Olusegun O Soge
- ¶Neisseria Reference Laboratory, Department of Global Health, University of Washington, Seattle, Washington
| | - King K Holmes
- ¶Neisseria Reference Laboratory, Department of Global Health, University of Washington, Seattle, Washington; ‖Departments of Medicine and Global Health, University of Washington, Seattle, Washington
| | - Ann E Jerse
- **Department of Microbiology and Immunology, F. Edward Herbert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Magnus Unemo
- ‡‡WHO Collaborating Centre for Gonorrhoea and other Sexually Transmitted Infections, National Reference Laboratory for Pathogenic Neisseria, Department of Laboratory Medicine, Microbiology, Örebro University Hospital, Örebro, Sweden
| | - Aleksandra E Sikora
- From the ‡Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, Oregon;
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18
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The Gonococcal Transcriptome during Infection of the Lower Genital Tract in Women. PLoS One 2015; 10:e0133982. [PMID: 26244506 PMCID: PMC4526530 DOI: 10.1371/journal.pone.0133982] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 07/04/2015] [Indexed: 11/24/2022] Open
Abstract
Gonorrhea is a highly prevalent disease resulting in significant morbidity worldwide, with an estimated 106 cases reported annually. Neisseria gonorrhoeae, the causative agent of gonorrhea, colonizes and infects the human genital tract and often evades host immune mechanisms until successful antibiotic treatment is used. The alarming increase in antibiotic-resistant strains of N. gonorrhoeae, the often asymptomatic nature of this disease in women and the lack of a vaccine directed at crucial virulence determinants have prompted us to perform transcriptome analysis to understand gonococcal gene expression patterns during natural infection. We sequenced RNA extracted from cervico-vaginal lavage samples collected from women recently exposed to infected male partners and determined the complete N. gonorrhoeae transcriptome during infection of the lower genital tract in women. On average, 3.19% of total RNA isolated from female samples aligned to the N. gonorrhoeae NCCP11945 genome and 1750 gonococcal ORFs (65% of all protein-coding genes) were transcribed. High expression in vivo was observed in genes encoding antimicrobial efflux pumps, iron response, phage production, pilin structure, outer membrane structures and hypothetical proteins. A parallel analysis was performed using the same strains grown in vitro in a chemically defined media (CDM). A total of 140 genes were increased in expression during natural infection compared to growth in CDM, and 165 genes were decreased in expression. Large differences were found in gene expression profiles under each condition, particularly with genes involved in DNA and RNA processing, iron, transposase, pilin and lipoproteins. We specifically interrogated genes encoding DNA binding regulators and iron-scavenging proteins, and identified increased expression of several iron-regulated genes, including tbpAB and fbpAB, during infection in women as compared to growth in vitro, suggesting that during infection of the genital tract in women, the gonococcus is exposed to an iron deplete environment. Collectively, we demonstrate that a large portion of the gonococcal genome is expressed and regulated during mucosal infection including genes involved in regulatory functions and iron scavenging.
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19
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Abstract
Gonorrhoea continues to seriously impact human society with an estimated 106 million new infections occurring annually. The consequence of gonorrhoea on reproductive and neonatal health is especially concerning as is its role in the spread of HIV. Current control measures rely on the identification and treatment of infected individuals and their sexual contacts. The success of this strategy, which is already inadequate, is lessened by poor diagnostic capabilities in many parts of the world and challenged by the rapid emergence of antibiotic-resistant strains. The potential of untreatable gonorrhoea is now real, and a gonorrhoea vaccine is seriously needed. Historically, gonorrhoea vaccine research has been hampered by the antigenic variability of the gonococcal surface, a lack of known protective mechanisms, and the absence of a small laboratory animal model for testing candidate vaccines and manipulating host responses. Here we discuss recent advances that have rekindled research efforts towards a gonorrhoea vaccine. Several conserved and semiconserved vaccine antigens have been identified that elicit bactericidal antibodies or inhibit target function. A mouse genital tract infection model is available for systematic testing of vaccines, and transgenic mice have been developed to relieve host restrictions. Additionally, several immunological advances have been made including the identification of mechanisms by which Neisseria gonorrhoeae suppresses the adaptive response and the demonstration that Th1 responses clear experimental infection in mice and induce a protective memory response. We also discuss important issues with respect to product development that must be considered when entering the vaccine pipeline.
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Affiliation(s)
- Ann E Jerse
- , Department of Microbiology and Immunology, F. Edward Hebért School of Medicine, Uniformed Services University, , Bethesda, Maryland, USA
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20
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Jerse AE, Bash MC, Russell MW. Vaccines against gonorrhea: current status and future challenges. Vaccine 2013; 32:1579-87. [PMID: 24016806 DOI: 10.1016/j.vaccine.2013.08.067] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 06/10/2013] [Accepted: 08/17/2013] [Indexed: 01/11/2023]
Abstract
Gonorrhea occurs at high incidence throughout the world and significantly impacts reproductive health and the spread of human immunodeficiency virus. Current control measures are inadequate and seriously threatened by the rapid emergence of antibiotic resistance. Progress on gonorrhea vaccines has been slow; however, recent advances justify significant effort in this area. Conserved vaccine antigens have been identified that elicit bactericidal antibodies and, or play key roles in pathogenesis that could be targeted by a vaccine-induced response. A murine genital tract infection model is available for systematic testing of antigens, immunization routes and adjuvants, and transgenic mice exist to relieve some host restrictions. Furthermore, mechanisms by which Neisseria gonorrhoeae avoids inducing a protective adaptive response are being elucidated using human cells and the mouse model. Induction of a Th1 response in mice clears infection and induces a memory response, which suggests Th1-inducing adjuvants may be key in vaccine-induced protection. Continued research in this area should include human testing and clinical studies to confirm or negate findings from experimental systems and to define protective host factors.
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Affiliation(s)
- Ann E Jerse
- Department of Microbiology and Immunology, F. Edward Hebért School of Medicine, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814-4799, USA.
| | - Margaret C Bash
- Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, 1400 Rockville Pike, Bethesda, MD 20814, USA.
| | - Michael W Russell
- Department of Microbiology and Immunology, Witebsky Center for Microbial Pathogenesis and Immunology, University at Buffalo, 3435 Main Street, Buffalo, NY 14214-3000, USA.
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21
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Hopper AC, Li Y, Cole JA. A critical role for the cccA gene product, cytochrome c2, in diverting electrons from aerobic respiration to denitrification in Neisseria gonorrhoeae. J Bacteriol 2013; 195:2518-29. [PMID: 23543713 PMCID: PMC3676072 DOI: 10.1128/jb.02300-12] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 03/14/2013] [Indexed: 01/22/2023] Open
Abstract
Neisseria gonorrhoeae is a microaerophile that, when oxygen availability is limited, supplements aerobic respiration with a truncated denitrification pathway, nitrite reduction to nitrous oxide. We demonstrate that the cccA gene of Neisseria gonorrhoeae strain F62 (accession number NG0292) is expressed, but the product, cytochrome c2, accumulates to only low levels. Nevertheless, a cccA mutant reduced nitrite at about half the rate of the parent strain. We previously reported that cytochromes c4 and c5 transfer electrons to cytochrome oxidase cbb3 by two independent pathways and that the CcoP subunit of cytochrome oxidase cbb3 transfers electrons to nitrite. We show that mutants defective in either cytochrome c4 or c5 also reduce nitrite more slowly than the parent. By combining mutations in cccA (Δc2), cycA (Δc4), cycB (Δc5), and ccoP (ccoP-C368A), we demonstrate that cytochrome c2 is required for electron transfer from cytochrome c4 via the third heme group of CcoP to the nitrite reductase, AniA, and that cytochrome c5 transfers electrons to nitrite reductase by an independent pathway. We propose that cytochrome c2 forms a complex with cytochrome oxidase. If so, the redox state of cytochrome c2 might regulate electron transfer to nitrite or oxygen. However, our data are more consistent with a mechanism in which cytochrome c2 and the CcoQ subunit of cytochrome oxidase form alternative complexes that preferentially catalyze nitrite and oxygen reduction, respectively. Comparison with the much simpler electron transfer pathway for nitrite reduction in the meningococcus provides fascinating insights into niche adaptation within the pathogenic neisseriae.
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Affiliation(s)
- Amanda C Hopper
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom
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22
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Shewell LK, Ku SC, Schulz BL, Jen FEC, Mubaiwa TD, Ketterer MR, Apicella MA, Jennings MP. Recombinant truncated AniA of pathogenic Neisseria elicits a non-native immune response and functional blocking antibodies. Biochem Biophys Res Commun 2013; 431:215-20. [PMID: 23313483 DOI: 10.1016/j.bbrc.2012.12.132] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 12/30/2012] [Indexed: 10/27/2022]
Abstract
AniA of the pathogenic Neisseria is glycosylated in its C-terminal repeat region by the pilin glycosylation (pgl) pathway. AniA appears to be unique among bacterial nitrite reductases as it contains an N-terminal extension that includes a lipid modification site as well as a C-terminal extension that is glycosylated. Immunising with various glycoforms of the AniA protein demonstrated a strong humoral immune response to the basal monosaccharide. In addition, when animals were immunised with a truncated form of AniA, completely lacking the glycosylated C-terminal region, the antibody response was directed against AniA regardless of the glycosylation state of the protein. Immuno-SEM confirmed that AniA is expressed on the cell surface in Neisseria gonorrhoeae. Antisera generated against a truncated, non-glycosylated, recombinant form of the AniA protein are capable of blocking nitrite reductase function in a whole cell assay. We propose that recombinant modified AniA has potential as a vaccine antigen for N. gonorrhoeae.
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Affiliation(s)
- Lucy K Shewell
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
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23
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Castiglione N, Rinaldo S, Giardina G, Stelitano V, Cutruzzolà F. Nitrite and nitrite reductases: from molecular mechanisms to significance in human health and disease. Antioxid Redox Signal 2012; 17:684-716. [PMID: 22304560 DOI: 10.1089/ars.2011.4196] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Nitrite, previously considered physiologically irrelevant and a simple end product of endogenous nitric oxide (NO) metabolism, is now envisaged as a reservoir of NO to be activated in response to oxygen (O(2)) depletion. In the first part of this review, we summarize and compare the mechanisms of nitrite-dependent production of NO in selected bacteria and in eukaryotes. Bacterial nitrite reductases, which are copper or heme-containing enzymes, play an important role in the adaptation of pathogens to O(2) limitation and enable microrganisms to survive in the human body. In mammals, reduction of nitrite to NO under hypoxic conditions is carried out in tissues and blood by an array of metalloproteins, including heme-containing proteins and molybdenum enzymes. In humans, tissues play a more important role in nitrite reduction, not only because most tissues produce more NO than blood, but also because deoxyhemoglobin efficiently scavenges NO in blood. In the second part of the review, we outline the significance of nitrite in human health and disease and describe the recent advances and pitfalls of nitrite-based therapy, with special attention to its application in cardiovascular disorders, inflammation, and anti-bacterial defence. It can be concluded that nitrite (as well as nitrate-rich diet for long-term applications) may hold promise as therapeutic agent in vascular dysfunction and ischemic injury, as well as an effective compound able to promote angiogenesis.
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Affiliation(s)
- Nicoletta Castiglione
- Department of Biochemical Sciences, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy
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24
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Cole JA. Legless pathogens: how bacterial physiology provides the key to understanding pathogenicity. MICROBIOLOGY-SGM 2012; 158:1402-1413. [PMID: 22493300 DOI: 10.1099/mic.0.059048-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
This review argues that knowledge of microbial physiology and metabolism is a prerequisite to understanding mechanisms of pathogenicity. The ability of Neisseria gonorrhoeae to cope with stresses such as those found during infection requires a sialyltransferase to sialylate its lipopolysaccharide using host-derived CMP-NANA in the human bloodstream, the ability to oxidize lactate that is abundant in the human body, outer-membrane lipoproteins that provide the first line of protection against oxidative and nitrosative stress, regulation of NO reduction independently from the nitrite reductase that forms NO, an extra haem group on the C-terminal extension of a cytochrome oxidase subunit, and a respiratory capacity far in excess of metabolic requirements. These properties are all normal components of neisserial physiology; they would all fail rigid definitions of a pathogenicity determinant. In anaerobic cultures of enteric bacteria, duplicate pathways for nitrate reduction to ammonia provide a selective advantage when nitrate is either abundant or scarce. Selection of these alternative pathways is in part regulated by two parallel two-component regulatory systems. NarX-NarL primarily ensures that nitrate is reduced in preference to thermodynamically less favourable terminal electron acceptors, but NarQ-NarP facilitates reduction of limited quantities of nitrate or other, less favourable, terminal electron acceptors in preference to fermentative growth. How enteric bacteria repair damage caused by nitrosative and oxidative damage inflicted by host defences is less well understood. In both N. gonorrhoeae and Escherichia coli, parallel pathways that duplicate particular biochemical functions are far from redundant, but fulfil specific physiological roles.
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Affiliation(s)
- Jeffrey A Cole
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
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25
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Isabella VM, Clark VL. Identification of a conserved protein involved in anaerobic unsaturated fatty acid synthesis in Neiserria gonorrhoeae: implications for facultative and obligate anaerobes that lack FabA. Mol Microbiol 2011; 82:489-501. [PMID: 21895795 DOI: 10.1111/j.1365-2958.2011.07826.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Transcriptome analysis of the facultative anaerobe, Neisseria gonorrhoeae, revealed that many genes of unknown function were induced under anaerobic conditions. Mutation of one such gene, NGO1024, encoding a protein belonging to the 2-nitropropane dioxygenase-like superfamily of proteins, was found to result in an inability of gonococci to grow anaerobically. Anaerobic growth of an NG1024 mutant was restored upon supplementation with unsaturated fatty acids (UFA), but not with the saturated fatty acid palmitate. Gonococcal fatty acid profiles confirmed that NGO1024 was involved in UFA synthesis anaerobically, but not aerobically, demonstrating that gonococci contain two distinct pathways for the production of UFAs, with a yet unidentified aerobic mechanism, and an anaerobic mechanism involving NGO1024. Expression of genes involved in classical anaerobic UFA synthesis, fabA, fabM and fabB, was toxic in gonococci and unable to complement a NGO1024 mutation, suggesting that the chemistry involved in gonococcal anaerobic UFA synthesis is distinct from that of the classical pathway. NGO1024 homologues, which we suggest naming UfaA, form a distinct lineage within the 2-nitropropane dioxygenase-like superfamily, and are found in many facultative and obligate anaerobes that produce UFAs but lack fabA, suggesting that UfaA is part of a widespread pathway involved in UFA synthesis.
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Affiliation(s)
- Vincent M Isabella
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Box 672, 601 Elmwood Ave, Rochester, NY 14642, USA
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The Moraxella catarrhalis nitric oxide reductase is essential for nitric oxide detoxification. J Bacteriol 2011; 193:2804-13. [PMID: 21441505 DOI: 10.1128/jb.00139-11] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Moraxella catarrhalis is a Gram-negative obligate aerobe that is an important cause of human respiratory tract infections. The M. catarrhalis genome encodes a predicted truncated denitrification pathway that reduces nitrate to nitrous oxide. We have previously shown that expression of both the M. catarrhalis aniA (encoding a nitrite reductase) and norB (encoding a putative nitric oxide reductase) genes is repressed by the transcriptional regulator NsrR under aerobic conditions and that M. catarrhalis O35E nsrR mutants are unable to grow in the presence of low concentrations of nitrite (W. Wang, et al., J. Bacteriol. 190:7762-7772, 2008). In this study, we constructed an M. catarrhalis norB mutant and showed that planktonic growth of this mutant is inhibited by low levels of nitrite, whether or not an nsrR mutation is present. To determine the importance of NorB in this truncated denitrification pathway, we analyzed the metabolism of nitrogen oxides by norB, aniA norB, and nsrR norB mutants. We found that norB mutants are unable to reduce nitric oxide and produce little or no nitrous oxide from nitrite. Furthermore, nitric oxide produced from nitrite by the AniA protein is bactericidal for a Moraxella catarrhalis O35E norB mutant but not for wild-type O35E bacteria under aerobic growth conditions in vitro, suggesting that nitric oxide catabolism in M. catarrhalis is accomplished primarily by the norB gene product. Measurement of bacterial protein S-nitrosylation directly implicates nitrosative stress resulting from AniA-dependent nitric oxide formation as a cause of the growth inhibition of norB and nsrR mutants by nitrite.
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Isabella VM, Clark VL. Deep sequencing-based analysis of the anaerobic stimulon in Neisseria gonorrhoeae. BMC Genomics 2011; 12:51. [PMID: 21251255 PMCID: PMC3032703 DOI: 10.1186/1471-2164-12-51] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Accepted: 01/20/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Maintenance of an anaerobic denitrification system in the obligate human pathogen, Neisseria gonorrhoeae, suggests that an anaerobic lifestyle may be important during the course of infection. Furthermore, mounting evidence suggests that reduction of host-produced nitric oxide has several immunomodulary effects on the host. However, at this point there have been no studies analyzing the complete gonococcal transcriptome response to anaerobiosis. Here we performed deep sequencing to compare the gonococcal transcriptomes of aerobically and anaerobically grown cells. Using the information derived from this sequencing, we discuss the implications of the robust transcriptional response to anaerobic growth. RESULTS We determined that 198 chromosomal genes were differentially expressed (~10% of the genome) in response to anaerobic conditions. We also observed a large induction of genes encoded within the cryptic plasmid, pJD1. Validation of RNA-seq data using translational-lacZ fusions or RT-PCR demonstrated the RNA-seq results to be very reproducible. Surprisingly, many genes of prophage origin were induced anaerobically, as well as several transcriptional regulators previously unknown to be involved in anaerobic growth. We also confirmed expression and regulation of a small RNA, likely a functional equivalent of fnrS in the Enterobacteriaceae family. We also determined that many genes found to be responsive to anaerobiosis have also been shown to be responsive to iron and/or oxidative stress. CONCLUSIONS Gonococci will be subject to many forms of environmental stress, including oxygen-limitation, during the course of infection. Here we determined that the anaerobic stimulon in gonococci was larger than previous studies would suggest. Many new targets for future research have been uncovered, and the results derived from this study may have helped to elucidate factors or mechanisms of virulence that may have otherwise been overlooked.
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Affiliation(s)
- Vincent M Isabella
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Box 672, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Virginia L Clark
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Box 672, 601 Elmwood Avenue, Rochester, NY 14642, USA
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Genetic, structural, and antigenic analyses of glycan diversity in the O-linked protein glycosylation systems of human Neisseria species. J Bacteriol 2010; 192:2816-29. [PMID: 20363948 DOI: 10.1128/jb.00101-10] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Bacterial capsular polysaccharides and lipopolysaccharides are well-established ligands of innate and adaptive immune effectors and often exhibit structural and antigenic variability. Although many surface-localized glycoproteins have been identified in bacterial pathogens and symbionts, it not clear if and how selection impacts associated glycoform structure. Here, a systematic approach was devised to correlate gene repertoire with protein-associated glycoform structure in Neisseria species important to human health and disease. By manipulating the protein glycosylation (pgl) gene content and assessing the glycan structure by mass spectrometry and reactivity with monoclonal antibodies, it was established that protein-associated glycans are antigenically variable and that at least nine distinct glycoforms can be expressed in vitro. These studies also revealed that in addition to Neisseria gonorrhoeae strain N400, one other gonococcal strain and isolates of Neisseria meningitidis and Neisseria lactamica exhibit broad-spectrum O-linked protein glycosylation. Although a strong correlation between pgl gene content, glycoform expression, and serological profile was observed, there were significant exceptions, particularly with regard to levels of microheterogeneity. This work provides a technological platform for molecular serotyping of neisserial protein glycans and for elucidating pgl gene evolution.
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Hopper A, Tovell N, Cole J. A physiologically significant role in nitrite reduction of the CcoP subunit of the cytochrome oxidasecbb3fromNeisseria gonorrhoeae. FEMS Microbiol Lett 2009; 301:232-40. [DOI: 10.1111/j.1574-6968.2009.01824.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Wade JJ, Graver MA. A liquid medium permitting anaerobic growth of Neisseria gonorrhoeae. J Microbiol Methods 2009; 79:364-6. [PMID: 19796658 DOI: 10.1016/j.mimet.2009.09.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2009] [Revised: 09/11/2009] [Accepted: 09/18/2009] [Indexed: 01/04/2023]
Abstract
Neisseria gonorrhoeae will grow in an anaerobic atmosphere if provided with nitrite as a terminal electron acceptor, and it is increasingly apparent that this important pathogen may grow anaerobically in vivo. By modifying a previously described chemically-defined medium we have produced a liquid medium capable of supporting growth of N. gonorrhoeae under strictly anaerobic conditions.
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Affiliation(s)
- Jeremy James Wade
- Health Protection Agency London Region Laboratory, Medical Microbiology, King's College Hospital, Denmark Hill, London, SE5 9RS, United Kingdom.
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Transcriptional profiling identifies the metabolic phenotype of gonococcal biofilms. Infect Immun 2009; 77:3522-32. [PMID: 19528210 DOI: 10.1128/iai.00036-09] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Neisseria gonorrhoeae, the etiologic agent of gonorrhea, is frequently asymptomatic in women, often leading to chronic infections. One factor contributing to this may be biofilm formation. N. gonorrhoeae can form biofilms on glass and plastic surfaces. There is also evidence that biofilm formation may occur during natural cervical infection. To further study the mechanism of gonococcal biofilm formation, we compared transcriptional profiles of N. gonorrhoeae biofilms to planktonic profiles. Biofilm RNA was extracted from N. gonorrhoeae 1291 grown for 48 h in continuous-flow chambers over glass. Planktonic RNA was extracted from the biofilm runoff. In comparing biofilm with planktonic growth, 3.8% of the genome was differentially regulated. Genes that were highly upregulated in biofilms included aniA, norB, and ccp. These genes encode enzymes that are central to anaerobic respiratory metabolism and stress tolerance. Downregulated genes included members of the nuo gene cluster, which encodes the proton-translocating NADH dehydrogenase. Furthermore, it was observed that aniA, ccp, and norB insertional mutants were attenuated for biofilm formation on glass and transformed human cervical epithelial cells. These data suggest that biofilm formation by the gonococcus may represent a response that is linked to the control of nitric oxide steady-state levels during infection of cervical epithelial cells.
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Identification of a repressor of a truncated denitrification pathway in Moraxella catarrhalis. J Bacteriol 2008; 190:7762-72. [PMID: 18820017 DOI: 10.1128/jb.01032-08] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Growth of Moraxella catarrhalis in a biofilm resulted in marked upregulation of two open reading frames (ORFs), aniA and norB, predicted to encode a nitrite reductase and a nitric oxide reductase, respectively (W. Wang, L. Reitzer, D. A. Rasko, M. M. Pearson, R. J. Blick, C. Laurence, and E. J. Hansen, Infect. Immun. 75:4959-4971, 2007). An ORF designated nsrR, which was located between aniA and norB, was shown to encode a predicted transcriptional regulator. Inactivation of nsrR resulted in increased expression of aniA and norB in three different M. catarrhalis strains, as measured by both DNA microarray analysis and quantitative reverse transcriptase PCR. Provision of a wild-type nsrR gene in trans in an nsrR mutant resulted in decreased expression of the AniA protein. DNA microarray analysis revealed that two other ORFs (MC ORF 683 and MC ORF 1550) were also consistently upregulated in an nsrR mutant. Consumption of both nitrite and nitric oxide occurred more rapidly with cells of an nsrR mutant than with wild-type cells. However, growth of nsrR mutants was completely inhibited by a low level of sodium nitrite. This inhibition of growth by nitrite was significantly reversed by introduction of an aniA mutation into the nsrR mutant and was completely reversed by the presence of a wild-type nsrR gene in trans. NsrR regulation of the expression of aniA was sensitive to nitrite, whereas NsrR regulation of norB was sensitive to nitric oxide.
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Stefanelli P, Colotti G, Neri A, Salucci ML, Miccoli R, Di Leandro L, Ippoliti R. Molecular characterization of nitrite reductase gene (aniA) and gene product inNeisseria meningitidisisolates: IsaniA essential for meningococcal survival? IUBMB Life 2008; 60:629-36. [DOI: 10.1002/iub.95] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Abstract
This chapter illustrates some of the considerations that need to be made when analyzing nitric oxide (NO) metabolism of the pathogen Neisseria meningitidis. These considerations are pertinent to other bacteria and, in particular, other pathogens. First, because of the small culture volumes that can generally be managed safely, culture experiments are maintained in small volumes. We show a method for simultaneously measuring oxygen and nitric oxide during growth of N. meningitidis in a bioreactor/electrode chamber adapted from commercially available equipment. NO and NO-generating compounds can be used to investigate the impact of NO on N. meningitidis metabolism and gene expression in pure culture. Also, methods are described for analyzing the role of NO during the interaction between N. meningitidis and human macrophage cells that generate NO.
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Isabella V, Wright LF, Barth K, Spence JM, Grogan S, Genco CA, Clark VL. cis- and trans-acting elements involved in regulation of norB (norZ), the gene encoding nitric oxide reductase in Neisseria gonorrhoeae. MICROBIOLOGY-SGM 2008; 154:226-239. [PMID: 18174141 DOI: 10.1099/mic.0.2007/010470-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The ability of Neisseria gonorrhoeae to reduce nitric oxide (NO) may have important immunomodulatory effects on the host during infection. Therefore, a comprehensive understanding of the regulatory mechanism of the nitric oxide reductase gene (norB) needs to be elucidated. To accomplish this, we analysed the functional regions of the norB upstream region. The promoter contains an extended -10 motif (TGNTACAAT) that is required for high-level expression. Deletion and substitution analysis of the norB upstream region revealed that no sequence upstream of the -10 motif is involved in norB regulation under anaerobic conditions or in the presence of NO. However, replacement of a 29 bp inverted repeat sequence immediately downstream of the extended -10 motif gave high levels of aerobic expression of a norB : : lacZ fusion. Insertional inactivation of gonococcal nsrR, predicted to bind to this inverted repeat sequence, resulted in the loss of norB repression and eliminated NO induction capacity. Single-copy complementation of nsrR in trans restored regulation of both norB transcription and NorB activity by NO. In Escherichia coli, expression of a gonococcal nsrR gene repressed gonococcal norB; induction of norB occurred in the presence of exogenously added NO. NsrR also regulates aniA and dnrN, as well as its own expression. We also determined that Fur regulates norB by a novel indirect activation method, by preventing the binding of a gonococcal ArsR homologue, a second repressor whose putative binding site overlaps the Fur binding site.
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Affiliation(s)
- Vincent Isabella
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Box 672, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Lori F Wright
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Box 672, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Kenneth Barth
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Box 672, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Janice M Spence
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Box 672, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Susan Grogan
- Department of Microbiology, Section of Infectious Diseases, Boston University School of Medicine, Boston, MA 02118, USA
| | - Caroline A Genco
- Department of Medicine, Section of Molecular Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Virginia L Clark
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Box 672, 601 Elmwood Avenue, Rochester, NY 14642, USA
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The small FNR regulon of Neisseria gonorrhoeae: comparison with the larger Escherichia coli FNR regulon and interaction with the NarQ-NarP regulon. BMC Genomics 2007; 8:35. [PMID: 17261178 PMCID: PMC1802743 DOI: 10.1186/1471-2164-8-35] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2006] [Accepted: 01/29/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Neisseria gonorrhoeae can survive during oxygen starvation by reducing nitrite to nitrous oxide catalysed by the nitrite and nitric oxide reductases, AniA and NorB. The oxygen-sensing transcription factor, FNR, is essential for transcription activation at the aniA promoter, and full activation also requires the two-component regulatory system, NarQ-NarP, and the presence of nitrite. The only other gene known to be activated by the gonococcal FNR is ccp encoding a cytochrome c peroxidase, and no FNR-repressed genes have been reported in the gonococcus. In contrast, FNR acts as both an activator and repressor involved in the control of more than 100 operons in E. coli regulating major changes in the adaptation from aerobic to anaerobic conditions. In this study we have performed a microarray-led investigation of the FNR-mediated responses in N. gonorrhoeae to determine the physiological similarities and differences in the role of FNR in cellular regulation in this species. RESULTS Microarray experiments show that N. gonorrhoeae FNR controls a much smaller regulon than its E. coli counterpart; it activates transcription of aniA and thirteen other genes, and represses transcription of six genes that include dnrN and norB. Having previously shown that a single amino acid substitution is sufficient to enable the gonococcal FNR to complement an E. coli fnr mutation, we investigated whether the gonococcal NarQ-NarP can substitute for E. coli NarX-NarL or NarQ-NarP. A plasmid expressing gonococcal narQ-narP was unable to complement E. coli narQP or narXL mutants, and was insensitive to nitrate or nitrite. Mutations that progressively changed the periplasmic nitrate sensing region, the P box, of E. coli NarQ to the sequence of the corresponding region of gonococcal NarQ resulted in loss of transcription activation in response to the availability of either nitrate or nitrite. However, the previously reported ligand-insensitive ability of gonococcal NarQ, the "locked on" phenotype, to activate either E. coli NarL or NarP was confirmed. CONCLUSION Despite the sequence similarities between transcription activators of E. coli and N. gonorrhoeae, these results emphasise the fundamental differences in transcription regulation between these two types of pathogenic bacteria.
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Overton TW, Whitehead R, Li Y, Snyder LAS, Saunders NJ, Smith H, Cole JA. Coordinated regulation of the Neisseria gonorrhoeae-truncated denitrification pathway by the nitric oxide-sensitive repressor, NsrR, and nitrite-insensitive NarQ-NarP. J Biol Chem 2006; 281:33115-26. [PMID: 16954205 DOI: 10.1074/jbc.m607056200] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neisseria gonorrhoeae survives anaerobically by reducing nitrite to nitrous oxide catalyzed by the nitrite and nitric oxide reductases, AniA and NorB. P(aniA) is activated by FNR (regulator of fumarate and nitrate reduction), the two-component regulatory system NarQ-NarP, and induced by nitrite; P(norB) is induced by NO independently of FNR by an uncharacterized mechanism. We report the results of microarray analysis, bioinformatic analysis, and chromatin immunoprecipitation, which revealed that only five genes with readily identified NarP-binding sites are differentially expressed in narP(+) and narP strains. These include three genes implicated in the truncated gonococcal denitrification pathway: aniA, norB, and narQ. We also report that (i) nitrite induces aniA transcription in a narP mutant; (ii) nitrite induction involves indirect inactivation by nitric oxide of a gonococcal repressor, NsrR, identified from a multigenome bioinformatic study; (iii) in an nsrR mutant, aniA, norB, and dnrN (encoding a putative reactive nitrogen species response protein) were expressed constitutively in the absence of nitrite, suggesting that NsrR is the only NO-sensing transcription factor in N. gonorrhoeae; and (iv) NO rather than nitrite is the ligand to which NsrR responds. When expressed in Escherichia coli, gonococcal NarQ and chimaeras of E. coli and gonococcal NarQ are ligand-insensitive and constitutively active: a "locked-on" phenotype. We conclude that genes involved in the truncated denitrification pathway of N. gonorrhoeae are key components of the small NarQP regulon, that NarP indirectly regulates P(norB) by stimulating NO production by AniA, and that NsrR plays a critical role in enabling gonococci to evade NO generated as a host defense mechanism.
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Affiliation(s)
- Tim W Overton
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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Seib KL, Wu HJ, Kidd SP, Apicella MA, Jennings MP, McEwan AG. Defenses against oxidative stress in Neisseria gonorrhoeae: a system tailored for a challenging environment. Microbiol Mol Biol Rev 2006; 70:344-61. [PMID: 16760307 PMCID: PMC1489540 DOI: 10.1128/mmbr.00044-05] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Neisseria gonorrhoeae is a host-adapted pathogen that colonizes primarily the human genitourinary tract. This bacterium encounters reactive oxygen and reactive nitrogen species as a consequence of localized inflammatory responses in the urethra of males and endocervix of females and also of the activity of commensal lactobacilli in the vaginal flora. This review describes recent advances in the understanding of defense systems against oxidative stress in N. gonorrhoeae and shows that while some of its defenses have similarities to the paradigm established with Escherichia coli, there are also some key differences. These differences include the presence of a defense system against superoxide based on manganese ions and a glutathione-dependent system for defense against nitric oxide which is under the control of a novel MerR-like transcriptional regulator. An understanding of the defenses against oxidative stress in N. gonorrhoeae and their regulation may provide new insights into the ways in which this bacterium survives challenges from polymorphonuclear leukocytes and urogenital epithelial cells.
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Affiliation(s)
- Kate L Seib
- The School of Molecular and Microbial Sciences, The University of Queensland, Brisbane 4072, Australia
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Cardinale JA, Clark VL. Determinants of nitric oxide steady-state levels during anaerobic respiration by Neisseria gonorrhoeae. Mol Microbiol 2006; 58:177-88. [PMID: 16164557 DOI: 10.1111/j.1365-2958.2005.04807.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Nitric oxide (NO) is an important host defence molecule that varies its immune stimulatory effects depending on the concentrations at which it is produced, with low concentrations (< 1 microM) promoting an anti-inflammatory host response while higher concentrations (>1 microM) lead to inflammatory responses. Neisseria gonorrhoeae grows anaerobically by anaerobic respiration using nitrite reductase (Nir) to convert nitrite to NO and nitric oxide reductase (Nor) to convert NO to nitrous oxide. As N. gonorrhoeae can both produce and degrade NO, we have begun a study of NO metabolism in this bacterium to understand how gonococcal manipulation of NO concentration may influence the inflammatory response during infection. N. gonorrhoeae has an apparent Nir Km of 33 microM nitrite and an apparent Nor Km of 1.2 microM NO. The maximum specific activities for Nir and Nor were 135 nmoles nitrite reduced per minute per OD600 (pH 6.7) and 270 nmoles NO reduced per minute per OD600 (pH 7.5) respectively. N. gonorrhoeae established a steady-state concentration of NO after nitrite addition that was dependent on the nitrite concentration until saturation at 1 mM nitrite. The NO steady-state level decreased as pH increased, and the ratio of activities of Nir and Nor correlated to the NO steady-state level. When the NO donor DETA/NO was used to simulate host NO production, N. gonorrhoeae also established a NO steady-state level. The concentration of NO at steady state was found to be a function of the concentration of NO generated by DETA/NO, with N. gonorrhoeae reducing the NO from proinflammatory (>1 microM) to anti-inflammatory (approximately 100 nM) concentrations. The implications of the ability of N. gonorrhoeae to maintain an anti-inflammatory NO concentration is discussed in relation to asymptomatic infection in women.
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Turner S, Moir J, Griffiths L, Overton T, Smith H, Cole J. Mutational and biochemical analysis of cytochrome c', a nitric oxide-binding lipoprotein important for adaptation of Neisseria gonorrhoeae to oxygen-limited growth. Biochem J 2005; 388:545-53. [PMID: 15689189 PMCID: PMC1138962 DOI: 10.1042/bj20041766] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Neisseria gonorrhoeae is a prolific source of c-type cytochromes. Five of the constitutively expressed cytochromes are predicted, based on in silico analysis of the N. gonorrhoeae genome, to be components of the cytochrome bc1 complex, cytochrome c oxidase cbb3 or periplasmic cytochromes involved in electron transfer reactions typical of a bacterium with a microaerobic physiology. Cytochrome c peroxidase was previously shown to be a lipoprotein expressed only during oxygen-limited growth. The final c-type cytochrome, cytochrome c', similar to cytochrome c peroxidase, includes a lipobox required for targeting to the outer membrane. Maturation of cytochrome c' was partially inhibited by globomycin, an antibiotic that specifically inhibits signal peptidase II, resulting in the accumulation of the prolipoprotein in the cytoplasmic membrane. Disruption of the gonococcal cycP gene resulted in an extended lag phase during microaerobic growth in the presence but not in the absence of nitrite, suggesting that cytochrome c' protects the bacteria from NO generated by nitrite reduction during adaptation to oxygen-limited growth. The cytochrome c' gene was overexpressed in Escherichia coli and recombinant cytochrome c' was shown to be targeted to the outer membrane. Spectroscopic evidence is presented showing that gonococcal cytochrome c' is similar to previously characterized cytochrome c' proteins and that it binds NO in vitro. The demonstration that two of the seven gonococcal c-type cytochromes fulfil specialized functions and are outer membrane lipoproteins suggests that the localization of these lipoproteins close to the bacterial surface provides effective protection against external assaults from reactive oxygen and reactive nitrogen species.
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Affiliation(s)
- Susan M. Turner
- *School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
| | - James W. B. Moir
- †Department of Biology, University of York, Heslington, York YO10 5YW, U.K
| | - Lesley Griffiths
- *School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
| | - Timothy W. Overton
- *School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
| | - Harry Smith
- ‡Medical School, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
| | - Jeff A. Cole
- *School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
- To whom correspondence should be addressed (email )
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Overton T, Reid EGF, Foxall R, Smith H, Busby SJW, Cole JA. Transcription activation at Escherichia coli FNR-dependent promoters by the gonococcal FNR protein: effects of a novel S18F substitution and comparisons with the corresponding substitution in E. coli FNR. J Bacteriol 2003; 185:4734-47. [PMID: 12896992 PMCID: PMC166479 DOI: 10.1128/jb.185.16.4734-4747.2003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Neisseria gonorrhoeae genome encodes a homologue of the Escherichia coli FNR protein (the fumarate and nitrate reductase regulator). Despite its similarity to E. coli FNR, the gonococcal FNR only partially complemented an E. coli fnr mutation. After error-prone PCR mutagenesis of the gonococcal fnr gene, we identified four mutant fnr derivatives carrying the same S18F substitution, and we showed that the mutant FNR could activate transcription from a range of class I and class II FNR-dependent promoters in E. coli. Prompted by the similarities between gonococcal and E. coli FNR, we made changes in gonococcal fnr that created substitutions that are equivalent to previously characterized substitutions in E. coli FNR. First, our experiments showed that cysteine, C116, in the gonococcal FNR, equivalent to C122 in E. coli FNR, is essential, presumably because, as in E. coli FNR, it binds to an iron-sulfur center. Second, the L22H and D148A substitutions in gonococcal FNR were made. These changes are equivalent to the L28H and D154A changes in E. coli FNR, which had been shown to increase FNR activity in the presence of oxygen. We show that the effects of these substitutions in gonococcal FNR are distinct from those of the S18F substitution. Similarly, substitutions in the putative activating regions of gonococcal FNR were made. We show that the activity of gonococcal FNR in E. coli can be increased by transplanting certain activating regions from E. coli FNR. The effects of these substitutions are additive to those due to S18F. From these data, we conclude that the effects of the S18F substitution in gonococcal FNR are distinct from the effects of the other substitutions. S18 is immediately adjacent to one of three N-terminal cysteine residues that coordinate the iron-sulfur center, and thus the S18F substitution is most likely to stabilize this center. Support for this came from complementary experiments in which we created the S24F substitution in E. coli FNR, which is equivalent to the S18F substitution in gonococcal FNR. Our results show that the S24F substitution changes the activity of E. coli FNR and that the changes are distinct from those due to previously characterized substitutions.
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Affiliation(s)
- Tim Overton
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
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Abstract
Neisseria meningitidis, the causative agent of meningococcal disease in humans, is likely to be exposed to nitrosative stress during natural colonization and disease. The genome of N. meningitidis includes the genes aniA and norB, predicted to encode nitrite reductase and nitric oxide (NO) reductase, respectively. These gene products should allow the bacterium to denitrify nitrite to nitrous oxide. We show that N. meningitidis can support growth microaerobically by the denitrification of nitrite via NO and that norB is required for anaerobic growth with nitrite. NorB and, to a lesser extent, the cycP gene product cytochrome c' are able to counteract toxicity due to exogenously added NO. Expression of these genes by N. meningitidis during colonization and disease may confer protection against exogenous or endogenous nitrosative stress.
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Affiliation(s)
- Muna F Anjum
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN
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Boulanger MJ, Murphy MEP. Crystal structure of the soluble domain of the major anaerobically induced outer membrane protein (AniA) from pathogenic Neisseria: a new class of copper-containing nitrite reductases. J Mol Biol 2002; 315:1111-27. [PMID: 11827480 DOI: 10.1006/jmbi.2001.5251] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The major anaerobically induced outer membrane protein (AniA) from pathogenic Neisseria gonorrhoeae is essential for cell growth under oxygen limiting conditions in the presence of nitrite and is protective against killing by human sera. A phylogenic analysis indicates that AniA is a member of a new class of copper-containing nitrite reductases. Expression of the soluble domain of AniA yields a protein capable of reducing nitrite with specific activity of 160 units/mg, approximately 50 % of that measured for the nitrite reductase from the strong soil denitrifier Alcaligenes faecalis S-6. The crystal structure of the soluble domain of AniA was solved by molecular replacement and sixfold averaging to a resolution of 2.4 A. The nitrite soaked AniA crystal structure refined to 1.95 A reveals a bidentate mode of substrate binding to the type II copper. Despite low sequence identity (approximately 30 %), the core cupredoxin fold of AniA is similar to that found in copper-containing nitrite reductases from soil bacteria. The main structural differences are localized to two attenuated surface loops that map to deletions in the sequence alignment. In soil nitrite reductases, one of these surface loops is positioned near the type I copper site and contributes residues to the docking surface for proteaceous electron donors. In AniA, the attenuation of this loop results in a restructured hydrophobic binding surface that may be required to interact with a lipid anchored azurin. The second attenuated loop is positioned on the opposite side of AniA and may facilitate a more intimate interaction with the lipid membrane. A unique combination of structural effectors surrounding the type I copper site of sAnia contribute to a unusual visible absorption spectra with components observed previously in either green or blue type I copper sites.
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Affiliation(s)
- Martin J Boulanger
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
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Householder TC, Fozo EM, Cardinale JA, Clark VL. Gonococcal nitric oxide reductase is encoded by a single gene, norB, which is required for anaerobic growth and is induced by nitric oxide. Infect Immun 2000; 68:5241-6. [PMID: 10948150 PMCID: PMC101784 DOI: 10.1128/iai.68.9.5241-5246.2000] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The gene encoding a nitric oxide reductase has been identified in Neisseria gonorrhoeae. The norB gene product shares significant identity with the nitric oxide reductases in Ralstonia eutropha and Synechocystis sp. and, like those organisms, the gonococcus lacks a norC homolog. The gonococcal norB gene was found to be required for anaerobic growth, but the absence of norB did not dramatically decrease anaerobic survival. In a wild-type background, induction of norB expression was seen anaerobically in the presence of nitrite but not anaerobically without nitrite or aerobically. norB expression is not regulated by FNR or NarP, but a functional aniA gene (which encodes an anaerobically induced outer membrane nitrite reductase) is necessary for expression. When aniA is constitutively expressed, norB expression can be induced both anaerobically and aerobically, but only in the presence of nitrite, suggesting that nitric oxide, which is likely to be produced by AniA as a product of nitrite reduction, is the inducing agent. This was confirmed with the use of the nitric oxide donor, spermine-nitric oxide complex, in an aniA null background both anaerobically and aerobically. NorB is important for gonococcal adaptation to an anaerobic environment, a physiologically relevant state during gonococcal infection. The presence of this enzyme, which is induced by nitric oxide, may also have implications in immune evasion and immunomodulation in the human host.
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Affiliation(s)
- T C Householder
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
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Lissenden S, Mohan S, Overton T, Regan T, Crooke H, Cardinale JA, Householder TC, Adams P, O'Conner CD, Clark VL, Smith H, Cole JA. Identification of transcription activators that regulate gonococcal adaptation from aerobic to anaerobic or oxygen-limited growth. Mol Microbiol 2000; 37:839-55. [PMID: 10972806 DOI: 10.1046/j.1365-2958.2000.02050.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Analysis of the Neisseria gonorrhoeae DNA sequence database revealed the presence of two genes, one encoding a protein predicted to be 37. 5% identical (50% similar) in amino acid sequence to the Escherichia coli FNR protein and the other encoding a protein 41% and 42% identical (54 and 51% sequence similarity) to the E. coli NarL and NarP proteins respectively. Both genes have been cloned into E. coli and insertionally inactivated in vitro. The mutated genes have been transformed into gonococci and recombined into the chromosome. The fnr mutation totally abolished and the narP mutation severely diminished the ability of gonococci to: (i) grow anaerobically; (ii) adapt to oxygen-limited growth; (iii) initiate transcription from the aniA promoter (which directs the expression of a copper-containing nitrite reductase, AniA, in response to the presence of nitrite); and (iv) reduce nitrite during growth in oxygen-limited media. The product of nitrite reduction was identified to be nitrous oxide. Immediately upstream of the narL/narP gene is an open reading frame that, if translated, would encode a homologue of the E. coli nitrate- and nitrite-sensing proteins NarX and NarQ. As transcription from the aniA promoter was not activated during oxygen-limited growth in the presence of nitrate, the gonococcal two-component regulatory system is designated NarQ-NarP rather than NarX-NarL. As far as we are aware, this is the first well-documented example of a two-component regulatory system working in partnership with a transcription activator in pathogenic neisseria. A 45 kDa c-type cytochrome that was synthesized during oxygen-limited, but not during oxygen sufficient, growth was identified as a homologue of cytochrome c peroxidases (CCP) of other bacteria. The gene for this cytochrome, designated ccp, was located, and its regulatory region was cloned into the promoter probe vector pLES94. Transcription from the ccp promoter was repressed during aerobic growth and induced during oxygen-limited growth and was totally FNR dependent, suggesting that the gonococcal FNR protein is a transcription activator of at least two genes. However, unlike AniA, synthesis of the CCP homologue was insensitive to the presence of nitrite during oxygen-limited growth.
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Affiliation(s)
- S Lissenden
- School of Biosciences, University of Birmingham, UK
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Cardinale JA, Clark VL. Expression of AniA, the major anaerobically induced outer membrane protein of Neisseria gonorrhoeae, provides protection against killing by normal human sera. Infect Immun 2000; 68:4368-9. [PMID: 10858263 PMCID: PMC101774 DOI: 10.1128/iai.68.7.4368-4369.2000] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Anaerobically grown Neisseria gonorrhoeae has previously been shown to have elevated serum resistance in the absence of exogenous CMP-N-acetylneuraminic acid or detectable sialylation. We hypothesized that the anaerobically induced gonococcal outer membrane protein AniA might have a role in this phenomenon, as it is the only known gonococcal protein that is absent under aerobic conditions. An N. gonorrhoeae F62 derivative, RUG7035, in which aniA is under control of the tac promoter, was used to examine the effect of AniA expression on serum resistance. In this study, we found that expression of AniA enhanced the serum resistance of N. gonorrhoeae and may account for these earlier observations.
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Affiliation(s)
- J A Cardinale
- Department of Microbiology and Immunology, University of Rochester, Rochester, New York 14642, USA
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47
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Segada LM, Carlone GM, Gheesling LL, Lesse AJ. Characterization of P1-deficient isogenic mutant of Haemophilus influenzae biogroup aegyptius associated with Brazilian purpuric fever. Microb Pathog 2000; 28:145-55. [PMID: 10702356 DOI: 10.1006/mpat.1999.0334] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Haemophilus influenzae biogroup aegyptius (formerly H. aegyptius) is the etiologic agent of Brazilian purpuric fever (BPF). A surface-exposed epitope on the outer membrane protein P1 is present on most strains of H. influenzae biogroup aegyptius associated with BPF but is absent in almost all non-disease associated strains. The role of the outer membrane protein P1 in the pathogenesis of this disease was evaluated by utilizing an isogenic P1-deficient mutant. We compared the ability of the wild type and P1 isogenic mutant to grow under various conditions. The P1-deficient strain grew at a similar rate to the wild type in both complex and chemically defined medium. The P1-deficient mutant also had a similar growth rate to the wild type under anaerobic conditions. Anaerobic growth, however, resulted in up-regulation of the P1 protein in the wild type strain. Three assays were used to examine the pathophysiologic role of the P1 protein in BPF: 1) serum resistance; 2) sustained bacteremia in the infant rat model; and 3) the human microvascular endothelial cell (HMEC) cytotoxicity assay. Both the mutant and wild-type strains were resistant to killing in 95% normal human serum. The P1-deficient strain was also as virulent as the wild type in both the infant rat model of bacteremia and in the HMEC-1 tissue culture model. These results demonstrate that serum resistance, sustained bacteremia in the infant rat, and cytotoxicity of HMEC cells occur in the absence of P1. The P1 protein is not essential for the pathogenic potential identified by these assays. However, these results demonstrate that an anaerobic environment is a potent physiologic regulator of P1 protein expression. The impact of anaerobiosis on protein expression and pathogenesis will require further investigations.
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Affiliation(s)
- L M Segada
- Department of Microbiology, State University of New York at Buffalo, New York, USA
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48
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Householder TC, Belli WA, Lissenden S, Cole JA, Clark VL. cis- and trans-acting elements involved in regulation of aniA, the gene encoding the major anaerobically induced outer membrane protein in Neisseria gonorrhoeae. J Bacteriol 1999; 181:541-51. [PMID: 9882668 PMCID: PMC93408 DOI: 10.1128/jb.181.2.541-551.1999] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/1998] [Accepted: 11/06/1998] [Indexed: 11/20/2022] Open
Abstract
AniA (formerly Pan1) is the major anaerobically induced outer membrane protein in Neisseria gonorrhoeae. AniA has been shown to be a major antigen in patients with gonococcal disease, and we have been studying its regulation in order to understand the gonococcal response to anaerobiosis and its potential role in virulence. This study presents a genetic analysis of aniA regulation. Through deletion analysis of the upstream region, we have determined the minimal promoter region necessary for aniA expression. This 130-bp region contains a sigma 70-type promoter and an FNR (fumarate and nitrate reductase regulator protein) binding site, both of which are absolutely required for anaerobic expression. Also located in the minimal promoter region are three T-rich direct repeats and several potential NarP binding sites. This 80-bp region is required for induction by nitrite. By site-directed mutagenesis of promoter sequences, we have determined that the transcription of aniA is initiated only from the sigma 70-type promoter. The gearbox promoter, previously believed to be the major promoter, does not appear to be active during anaerobiosis. The gonococcal FNR and NarP homologs are involved in the regulation of aniA, and we demonstrate that placing aniA under the control of the tac promoter compensates for the inability of a gonococcal fnr mutant to grow anaerobically.
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Affiliation(s)
- T C Householder
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
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49
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Pettit RK, Filiatrault MJ, Martin ES. Alteration of gonococcal protein expression in acidic culture. Infect Immun 1996; 64:1039-42. [PMID: 8641756 PMCID: PMC173877 DOI: 10.1128/iai.64.3.1039-1042.1996] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We grew Neisseria gonorrhoeae under acidic, neutral, and alkaline conditions and noted altered expression of at least 12 outer membrane proteins between 31 and 100 kDa in size. One protein whose expression was upregulated under acidic conditions was gonococcal heat shock protein 63. These proteins may contribute to the pathogenesis of gonorrhea in the urogenital tract.
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Affiliation(s)
- R K Pettit
- Department of Biology, Western Oregon State College, Monmouth, 97361, USA
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50
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Elkins C, Barkley KB, Carbonetti NH, Coimbre AJ, Sparling PF. Immunobiology of purified recombinant outer membrane porin protein I of Neisseria gonorrhoeae. Mol Microbiol 1994; 14:1059-75. [PMID: 7715444 DOI: 10.1111/j.1365-2958.1994.tb01339.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Gonococcal porins (Por) from strains FA19 (Por-1, serogroup A), MS11 (Por-2, serogroup B) and FA6434 (Por-5, a hybrid porin containing epitopes from both serogroups), were expressed in Escherichia coli and purified under non-denaturing conditions. Porins were inserted into liposomes, and they were bound by monoclonal antibodies which bind native Por and intact gonococci, but not denatured Por. All three recombinant porins (rPor) were highly immunogenic in rabbits without additional adjuvant. The rPor antisera were specific for Por by Western blotting and whole-cell radioimmunoprecipitation and were broadly cross-reactive within serogroups. Post-immune, but not pre-immune, sera bound to intact gonococci, induced deposition of complement components C3 and C9 onto gonococcal membranes and increased association with and activation of human neutrophils. Gonococci were not killed in bactericidal assays, and there was no phagocytic killing with gonococci opsonized with recombinant antisera. Lack of killing in bactericidal assays was not caused by the presence of blocking antibodies to the outer-membrane protein Rmp.
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Affiliation(s)
- C Elkins
- Department of Medicine, School of Medicine, University of North Carolina, Chapel Hill 27599
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