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Ghods S, Muszyński A, Yang H, Seelan RS, Mohammadi A, Hilson JS, Keiser G, Nichols FC, Azadi P, Ernst RK, Moradali F. The multifaceted role of c-di-AMP signaling in the regulation of Porphyromonas gingivalis lipopolysaccharide structure and function. Front Cell Infect Microbiol 2024; 14:1418651. [PMID: 38933693 PMCID: PMC11199400 DOI: 10.3389/fcimb.2024.1418651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 05/28/2024] [Indexed: 06/28/2024] Open
Abstract
Background This study unveils the intricate functional association between cyclic di-3',5'-adenylic acid (c-di-AMP) signaling, cellular bioenergetics, and the regulation of lipopolysaccharide (LPS) profile in Porphyromonas gingivalis, a Gram-negative obligate anaerobe considered as a keystone pathogen involved in the pathogenesis of chronic periodontitis. Previous research has identified variations in P. gingivalis LPS profile as a major virulence factor, yet the underlying mechanism of its modulation has remained elusive. Methods We employed a comprehensive methodological approach, combining two mutants exhibiting varying levels of c-di-AMP compared to the wild type, alongside an optimized analytical methodology that combines conventional mass spectrometry techniques with a novel approach known as FLATn. Results We demonstrate that c-di-AMP acts as a metabolic nexus, connecting bioenergetic status to nuanced shifts in fatty acid and glycosyl profiles within P. gingivalis LPS. Notably, the predicted regulator gene cdaR, serving as a potent regulator of c-di-AMP synthesis, was found essential for producing N-acetylgalactosamine and an unidentified glycolipid class associated with the LPS profile. Conclusion The multifaceted roles of c-di-AMP in bacterial physiology are underscored, emphasizing its significance in orchestrating adaptive responses to stimuli. Furthermore, our findings illuminate the significance of LPS variations and c-di-AMP signaling in determining the biological activities and immunostimulatory potential of P. gingivalis LPS, promoting a pathoadaptive strategy. The study expands the understanding of c-di-AMP pathways in Gram-negative species, laying a foundation for future investigations into the mechanisms governing variations in LPS structure at the molecular level and their implications for host-pathogen interactions.
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Affiliation(s)
- Shirin Ghods
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, KY, United States
| | - Artur Muszyński
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | - Hyojik Yang
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD, United States
| | - Ratnam S. Seelan
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, KY, United States
| | - Asal Mohammadi
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, KY, United States
| | - Jacob S. Hilson
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | - Griffin Keiser
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | - Frank C. Nichols
- Division of Periodontology, University of Connecticut School of Dental Medicine, Farmington, CT, United States
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | - Robert K. Ernst
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD, United States
| | - Fata Moradali
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, KY, United States
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Ovsepian A, Kardaras FS, Skoulakis A, Hatzigeorgiou AG. Microbial signatures in human periodontal disease: a metatranscriptome meta-analysis. Front Microbiol 2024; 15:1383404. [PMID: 38659984 PMCID: PMC11041396 DOI: 10.3389/fmicb.2024.1383404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 03/20/2024] [Indexed: 04/26/2024] Open
Abstract
The characterization of oral microbial communities and their functional potential has been shaped by metagenomics and metatranscriptomics studies. Here, a meta-analysis of four geographically and technically diverse oral shotgun metatranscriptomics studies of human periodontitis was performed. In total, 54 subgingival plaque samples, 27 healthy and 27 periodontitis, were analyzed. The core microbiota of the healthy and periodontitis group encompassed 40 and 80 species, respectively, with 38 species being common to both microbiota. The differential abundance analysis identified 23 genera and 26 species, that were more abundant in periodontitis. Our results not only validated previously reported genera and species associated with periodontitis with heightened statistical significance, but also elucidated additional genera and species that were overlooked in the individual studies. Functional analysis revealed a significant up-regulation in the transcription of 50 gene families (UniRef-90) associated with transmembrane transport and secretion, amino acid metabolism, surface protein and flagella synthesis, energy metabolism, and DNA supercoiling in periodontitis samples. Notably, the overwhelming majority of the identified gene families did not exhibit differential abundance when examined across individual datasets. Additionally, 4 bacterial virulence factor genes, including TonB dependent receptor from P. gingivalis, surface antigen BspA from T. forsynthia, and adhesin A (PsaA) and Type I glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from the Streptococcus genus, were also found to be significantly more transcribed in periodontitis group. Microbial co-occurrence analysis demonstrated that the periodontitis microbial network was less dense compared to the healthy network, but it contained more positive correlations between the species. Furthermore, there were discernible disparities in the patterns of interconnections between the species in the two networks, denoting the rewiring of the whole microbial network during the transition to the disease state. In summary, our meta-analysis has provided robust insights into the oral active microbiome and transcriptome in both health and disease.
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Affiliation(s)
- Armen Ovsepian
- DIANA-Lab, Department of Computer Science and Biomedical Informatics, University of Thessaly, Lamia, Greece
- Department of Microbiology, Hellenic Pasteur Institute, Athens, Greece
| | - Filippos S. Kardaras
- DIANA-Lab, Department of Computer Science and Biomedical Informatics, University of Thessaly, Lamia, Greece
- Department of Microbiology, Hellenic Pasteur Institute, Athens, Greece
| | - Anargyros Skoulakis
- DIANA-Lab, Department of Computer Science and Biomedical Informatics, University of Thessaly, Lamia, Greece
- Department of Microbiology, Hellenic Pasteur Institute, Athens, Greece
| | - Artemis G. Hatzigeorgiou
- DIANA-Lab, Department of Computer Science and Biomedical Informatics, University of Thessaly, Lamia, Greece
- Department of Microbiology, Hellenic Pasteur Institute, Athens, Greece
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3
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Olczak T, Śmiga M, Antonyuk SV, Smalley JW. Hemophore-like proteins of the HmuY family in the oral and gut microbiome: unraveling the mystery of their evolution. Microbiol Mol Biol Rev 2024; 88:e0013123. [PMID: 38305743 PMCID: PMC10966948 DOI: 10.1128/mmbr.00131-23] [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: 02/03/2024] Open
Abstract
SUMMARY Heme (iron protoporphyrin IX, FePPIX) is the main source of iron and PPIX for host-associated pathogenic bacteria, including members of the Bacteroidota (formerly Bacteroidetes) phylum. Porphyromonas gingivalis, a keystone oral pathogen, uses a unique heme uptake (Hmu) system, comprising a hemophore-like protein, designated as the first member of the novel HmuY family. Compared to classical, secreted hemophores utilized by Gram-negative bacteria or near-iron transporter domain-based hemophores utilized by Gram-positive bacteria, the HmuY family comprises structurally similar proteins that have undergone diversification during evolution. The best characterized are P. gingivalis HmuY and its homologs from Tannerella forsythia (Tfo), Prevotella intermedia (PinO and PinA), Bacteroides vulgatus (Bvu), and Bacteroides fragilis (BfrA, BfrB, and BfrC). In contrast to the two histidine residues coordinating heme iron in P. gingivalis HmuY, Tfo, PinO, PinA, Bvu, and BfrA preferentially use two methionine residues. Interestingly, BfrB, despite conserved methionine residue, binds the PPIX ring without iron coordination. BfrC binds neither heme nor PPIX in keeping with the lack of conserved histidine or methionine residues used by other members of the HmuY family. HmuY competes for heme binding and heme sequestration from host hemoproteins with other members of the HmuY family to increase P. gingivalis competitiveness. The participation of HmuY in the host immune response confirms its relevance in relation to the survival of P. gingivalis and its ability to induce dysbiosis not only in the oral microbiome but also in the gut microbiome or other host niches, leading to local injuries and involvement in comorbidities.
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Affiliation(s)
- Teresa Olczak
- Laboratory of Medical Biology, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
| | - Michał Śmiga
- Laboratory of Medical Biology, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
| | - Svetlana V. Antonyuk
- Molecular Biophysics Group, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, the University of Liverpool, Liverpool, United Kingdom
| | - John W. Smalley
- Institute of Life Course and Medical Sciences, School of Dentistry, the University of Liverpool, Liverpool, United Kingdom
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4
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McGregor AK, Chan ACK, Schroeder MD, Do LTM, Saini G, Murphy MEP, Wolthers KR. A new member of the flavodoxin superfamily from Fusobacterium nucleatum that functions in heme trafficking and reduction of anaerobilin. J Biol Chem 2023; 299:104902. [PMID: 37302554 PMCID: PMC10404700 DOI: 10.1016/j.jbc.2023.104902] [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: 03/04/2023] [Revised: 05/18/2023] [Accepted: 05/24/2023] [Indexed: 06/13/2023] Open
Abstract
Fusobacterium nucleatum is an opportunistic oral pathogen that is associated with various cancers. To fulfill its essential need for iron, this anaerobe will express heme uptake machinery encoded at a single genetic locus. The heme uptake operon includes HmuW, a class C radical SAM-dependent methyltransferase that degrades heme anaerobically to release Fe2+ and a linear tetrapyrrole called anaerobilin. The last gene in the operon, hmuF encodes a member of the flavodoxin superfamily of proteins. We discovered that HmuF and a paralog, FldH, bind tightly to both FMN and heme. The structure of Fe3+-heme-bound FldH (1.6 Å resolution) reveals a helical cap domain appended to the ⍺/β core of the flavodoxin fold. The cap creates a hydrophobic binding cleft that positions the heme planar to the si-face of the FMN isoalloxazine ring. The ferric heme iron is hexacoordinated to His134 and a solvent molecule. In contrast to flavodoxins, FldH and HmuF do not stabilize the FMN semiquinone but instead cycle between the FMN oxidized and hydroquinone states. We show that heme-loaded HmuF and heme-loaded FldH traffic heme to HmuW for degradation of the protoporphyrin ring. Both FldH and HmuF then catalyze multiple reductions of anaerobilin through hydride transfer from the FMN hydroquinone. The latter activity eliminates the aromaticity of anaerobilin and the electrophilic methylene group that was installed through HmuW turnover. Hence, HmuF provides a protected path for anaerobic heme catabolism, offering F. nucleatum a competitive advantage in the colonization of anoxic sites of the human body.
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Affiliation(s)
| | - Anson C K Chan
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Megan D Schroeder
- Department of Chemistry, University of British Columbia, Kelowna, Canada
| | - Long T M Do
- Department of Chemistry, University of British Columbia, Kelowna, Canada
| | - Gurpreet Saini
- Department of Chemistry, University of British Columbia, Kelowna, Canada
| | - Michael E P Murphy
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Kirsten R Wolthers
- Department of Chemistry, University of British Columbia, Kelowna, Canada.
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Smiline Girija AS. Moonlighting proteins [ML proteins]: The pandora's box of insidious oro-dental diseases. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119435. [PMID: 36738892 DOI: 10.1016/j.bbamcr.2023.119435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 01/27/2023] [Indexed: 02/05/2023]
Abstract
Oral pathogens survive in the harsh niche of the oral microbiome on account of a plethora of moonlighting [ML] proteins that can multitask in the oro-mucosal layers. ML proteins are considered as the complex protein hyperspace expressed in many oral bacterial pathogens and encompass many hypothetical and experimentally evidenced proteins that can efficiently assist in the initiation and progression of various oro-dental infections. With the propensity of multi-drug resistance and biofilm formation, unravelling the mysterious functions associated with the oral ML proteins could be essential in targeting the vital oral bacteria and their associated infections. This commentary thus throws insights onto the key clues on various ML proteins that can be considered for the development of therapeutic versatility to curtail the complications caused by various oral bacterial species.
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Affiliation(s)
- A S Smiline Girija
- Department of Microbiology, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences [SIMATS], Chennai 600077, Tamilnadu, India.
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6
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Modulatory Mechanisms of Pathogenicity in Porphyromonas gingivalis and Other Periodontal Pathobionts. Microorganisms 2022; 11:microorganisms11010015. [PMID: 36677306 PMCID: PMC9862357 DOI: 10.3390/microorganisms11010015] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/25/2022] [Accepted: 11/25/2022] [Indexed: 12/24/2022] Open
Abstract
The pathogenesis of periodontitis depends on a sustained feedback loop where bacterial virulence factors and immune responses both contribute to inflammation and tissue degradation. Periodontitis is a multifactorial disease that is associated with a pathogenic shift in the oral microbiome. Within this shift, low-abundance Gram-negative anaerobic pathobionts transition from harmless colonisers of the subgingival environment to a virulent state that drives evasion and subversion of innate and adaptive immune responses. This, in turn, drives the progression of inflammatory disease and the destruction of tooth-supporting structures. From an evolutionary perspective, bacteria have developed this phenotypic plasticity in order to respond and adapt to environmental stimuli or external stressors. This review summarises the available knowledge of genetic, transcriptional, and post-translational mechanisms which mediate the commensal-pathogen transition of periodontal bacteria. The review will focus primarily on Porphyromonas gingivalis.
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7
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陈 思, 邹 淑. [ Porphyromonas gingivalis HmuY and Its Possible Effect on the Pathogenesis of Periodontitis]. SICHUAN DA XUE XUE BAO. YI XUE BAN = JOURNAL OF SICHUAN UNIVERSITY. MEDICAL SCIENCE EDITION 2022; 53:1104-1109. [PMID: 36443060 PMCID: PMC10408960 DOI: 10.12182/20221160208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Indexed: 06/16/2023]
Abstract
Periodontitis, one of the most common inflammatory oral diseases in human beings, threatens the health of teeth and mouth and is closely associated with the development of many systemic diseases. Existing research about the pathogenesis of periodontitis mainly focuses on the oral microbial homeostasis and its complex interaction with the immune system. Among all the oral microorganisms, Porphyromonas gingivalis ( P. gingivalis) is considered to be the main pathogen causing chronic periodontitis. Recent studies have shown that P. gingivalis poesseses HmuY, a special heme binding protein, which binds with heme to provide essential nutrition for P. gingivalis and activates the host immune system. Therefore, HmuY plays an important role in the growth, proliferation, invasion, and pathogenesis of P. gingivalis and is a potential virulence factor of the bacteria. Existing studies on HmuY are limited to the host immune response that HmuY triggers, and there are still no conclusive findings on whether HmuY participates in the pathogenesis of periodontitis through other ways, such as influencing periodontal bone metabolism. Herein, we reviewed the latest research findings on the biological characteristics and physiological functions of HmuY and its relationship with chronic periodontitis, so as to provide new ideas for in-depth research and further explorations into the pathogenesis of chronic periodontitis.
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Affiliation(s)
- 思睿 陈
- 口腔疾病研究国家重点实验室 国家口腔疾病临床医学研究中心 四川大学华西口腔医院 口腔正畸科 (成都 610041)State Key Laboratory of Oral Diseases, National Clinical Research Center for OralDiseases, Department of Dental and Endodontic Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - 淑娟 邹
- 口腔疾病研究国家重点实验室 国家口腔疾病临床医学研究中心 四川大学华西口腔医院 口腔正畸科 (成都 610041)State Key Laboratory of Oral Diseases, National Clinical Research Center for OralDiseases, Department of Dental and Endodontic Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
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8
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Ibrahim I, Abdelhamed H, Baumgartner W, Wills RW, Awadin W, Elbegawy M, Lawrence ML, Karsi A. Pathological and Ultrastructural Characterization of an Edwardsiella ictaluri Triple hemR Mutant. JOURNAL OF AQUATIC ANIMAL HEALTH 2022; 34:116-133. [PMID: 35590426 DOI: 10.1002/aah.10154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/10/2022] [Accepted: 03/27/2022] [Indexed: 06/15/2023]
Abstract
Enteric septicemia of catfish, which is caused by Edwardsiella ictaluri, is detrimental to farmed Channel Catfish Ictalurus punctatus. The hemin receptor HemR is involved in binding and uptake of heme into bacteria. Here, we explored pathological and ultrastructural changes in catfish fry that were immunized with a triple hemR mutant of E. ictaluri and challenged with wild-type E. ictaluri (EiWT) 28 d after immunization. Following immunization, pathological changes in the triple hemR-immunized fry were less severe compared to the EiWT-exposed control fry. Widely disseminated bacteria and severe necrosis in most organs, especially the kidney and spleen, were detected in both groups at days 4, 5, and 6. Multifocal granulomatous encephalitis with bacteria was seen in hemR-immunized fry at days 21 and 28 and in EiWT-exposed control fry at day 14. Phagocytic cells in the kidney and spleen of EiWT-exposed control fry contained more replicating bacteria compared to hemR-immunized fry. During the EiWT challenge of immunized fry, a robust immune response was observed in the triple hemR-immunized fry compared to the sham-vaccinated group. Many activated phagocytic cells were detected in the kidney and spleen with fragmented or no bacteria in the triple hemR-immunized fry. Our data suggested that virulence of triple hemR was lower and the onset of the lesions was delayed compared to EiWT. Additionally, triple hemR-immunized fry could mount an immune response and had milder lesions compared to the sham control after EiWT exposure.
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Affiliation(s)
- Iman Ibrahim
- Department of Pathology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, 35516, Egypt
| | - Hossam Abdelhamed
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Wes Baumgartner
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, USA
| | - Robert W Wills
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Walaa Awadin
- Department of Pathology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, 35516, Egypt
| | - Mahmoud Elbegawy
- Department of Pathology, Faculty of Veterinary Medicine, Benisuef University, Benisuef, Egypt
| | - Mark L Lawrence
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Attila Karsi
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, 39762, USA
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9
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Śmiga M, Smalley JW, Ślęzak P, Brown JL, Siemińska K, Jenkins RE, Yates EA, Olczak T. Glycation of Host Proteins Increases Pathogenic Potential of Porphyromonas gingivalis. Int J Mol Sci 2021; 22:12084. [PMID: 34769513 PMCID: PMC8585099 DOI: 10.3390/ijms222112084] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 10/30/2021] [Accepted: 11/04/2021] [Indexed: 01/25/2023] Open
Abstract
The non-enzymatic addition of glucose (glycation) to circulatory and tissue proteins is a ubiquitous pathophysiological consequence of hyperglycemia in diabetes. Given the high incidence of periodontitis and diabetes and the emerging link between these conditions, it is of crucial importance to define the basic virulence mechanisms employed by periodontopathogens such as Porphyromonas gingivalis in mediating the disease process. The aim of this study was to determine whether glycated proteins are more easily utilized by P. gingivalis to stimulate growth and promote the pathogenic potential of this bacterium. We analyzed the properties of three commonly encountered proteins in the periodontal environment that are known to become glycated and that may serve as either protein substrates or easily accessible heme sources. In vitro glycated proteins were characterized using colorimetric assays, mass spectrometry, far- and near-UV circular dichroism and UV-visible spectroscopic analyses and SDS-PAGE. The interaction of glycated hemoglobin, serum albumin and type one collagen with P. gingivalis cells or HmuY protein was examined using spectroscopic methods, SDS-PAGE and co-culturing P. gingivalis with human keratinocytes. We found that glycation increases the ability of P. gingivalis to acquire heme from hemoglobin, mostly due to heme sequestration by the HmuY hemophore-like protein. We also found an increase in biofilm formation on glycated collagen-coated abiotic surfaces. We conclude that glycation might promote the virulence of P. gingivalis by making heme more available from hemoglobin and facilitating bacterial biofilm formation, thus increasing P. gingivalis pathogenic potential in vivo.
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Affiliation(s)
- Michał Śmiga
- Laboratory of Medical Biology, Faculty of Biotechnology, University of Wrocław, 14A F. Joliot-Curie St., 50-383 Wrocław, Poland; (M.Ś.); (P.Ś.); (K.S.)
| | - John W. Smalley
- Institute of Life Course and Medical Sciences, School of Dentistry, The University of Liverpool, Pembroke Place, Liverpool L3 5PS, UK; (J.W.S.); (J.L.B.)
| | - Paulina Ślęzak
- Laboratory of Medical Biology, Faculty of Biotechnology, University of Wrocław, 14A F. Joliot-Curie St., 50-383 Wrocław, Poland; (M.Ś.); (P.Ś.); (K.S.)
| | - Jason L. Brown
- Institute of Life Course and Medical Sciences, School of Dentistry, The University of Liverpool, Pembroke Place, Liverpool L3 5PS, UK; (J.W.S.); (J.L.B.)
| | - Klaudia Siemińska
- Laboratory of Medical Biology, Faculty of Biotechnology, University of Wrocław, 14A F. Joliot-Curie St., 50-383 Wrocław, Poland; (M.Ś.); (P.Ś.); (K.S.)
| | - Rosalind E. Jenkins
- CDSS Bioanalytical Facility, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Science, The University of Liverpool, Liverpool L69 3GE, UK;
| | - Edwin A. Yates
- Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Science, The University of Liverpool, Liverpool L69 7ZB, UK;
| | - Teresa Olczak
- Laboratory of Medical Biology, Faculty of Biotechnology, University of Wrocław, 14A F. Joliot-Curie St., 50-383 Wrocław, Poland; (M.Ś.); (P.Ś.); (K.S.)
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10
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Buzzanca D, Botta C, Ferrocino I, Alessandria V, Houf K, Rantsiou K. Functional pangenome analysis reveals high virulence plasticity of Aliarcobacter butzleri and affinity to human mucus. Genomics 2021; 113:2065-2076. [PMID: 33961980 DOI: 10.1016/j.ygeno.2021.05.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 04/27/2021] [Accepted: 05/01/2021] [Indexed: 12/12/2022]
Abstract
Aliarcobacter butzleri is an emerging pathogen that may cause enteritis in humans, however, the incidence of disease caused by this member of the Campylobacteriaceae family is still underestimated. Furthermore, little is known about the precise virulence mechanism and behavior during infection. Therefore, in the present study, through complementary use of comparative genomics and physiological tests on human gut models, we sought to elucidate the genetic background of a set of 32 A. butzleri strains of diverse origin and to explore the correlation with the ability to colonize and invade human intestinal cells in vitro. The simulated infection of human intestinal models showed a higher colonization rate in presence of mucus-producing cells. For some strains, human mucus significantly improved the resistance to physical removal from the in vitro mucosa, while short time-frame growth was even observed. Pangenome analysis highlighted a hypervariable accessory genome, not strictly correlated to the isolation source. Likewise, the strain phylogeny was unrelated to their shared origin, despite a certain degree of segregation was observed among strains isolated from different segments of the intestinal tract of pigs. The putative virulence genes detected in all strains were mostly encompassed in the accessory fraction of the pangenome. The LPS biosynthesis and in particular the chain glycosylation of the O-antigen is harbored in a region of high plasticity of the pangenome, which would indicate frequent horizontal gene transfer phenomena, as well as the involvement of this hypervariable structure in the adaptive behavior and sympatric evolution of A. butzleri. Results of the present study deepen the current knowledge on A. butzleri pangenome by extending the pool of genes regarded as virulence markers and provide bases to develop new diagnostic approaches for the detection of those strains with a higher virulence potential.
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Affiliation(s)
- Davide Buzzanca
- Department of Agricultural, Forest and Food Sciences (DISAFA), University of Turin, Italy; Department of Veterinary Public Health, Faculty of Veterinary Medicine, Ghent University, Belgium
| | - Cristian Botta
- Department of Agricultural, Forest and Food Sciences (DISAFA), University of Turin, Italy
| | - Ilario Ferrocino
- Department of Agricultural, Forest and Food Sciences (DISAFA), University of Turin, Italy
| | - Valentina Alessandria
- Department of Agricultural, Forest and Food Sciences (DISAFA), University of Turin, Italy
| | - Kurt Houf
- Department of Veterinary Public Health, Faculty of Veterinary Medicine, Ghent University, Belgium
| | - Kalliopi Rantsiou
- Department of Agricultural, Forest and Food Sciences (DISAFA), University of Turin, Italy.
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11
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Quercetin inhibits virulence properties of Porphyromas gingivalis in periodontal disease. Sci Rep 2020; 10:18313. [PMID: 33110205 PMCID: PMC7591570 DOI: 10.1038/s41598-020-74977-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 10/05/2020] [Indexed: 01/08/2023] Open
Abstract
Porphyromonas gingivalis is a causative agent in the onset and progression of periodontal disease. This study aims to investigate the effects of quercetin, a natural plant product, on P. gingivalis virulence properties including gingipain, haemagglutinin and biofilm formation. Antimicrobial effects and morphological changes of quercetin on P. gingivalis were detected. The effects of quercetin on gingipains activities and hemolytic, hemagglutination activities were evaluated using chromogenic peptides and sheep erythrocytes. The biofilm biomass and metabolism with different concentrations of quercetin were assessed by the crystal violet and MTT assay. The structures and thickness of the biofilms were observed by confocal laser scanning microscopy. Bacterial cell surface properties including cell surface hydrophobicity and aggregation were also evaluated. The mRNA expression of virulence and iron/heme utilization was assessed using real time-PCR. Quercetin exhibited antimicrobial effects and damaged the cell structure. Quercetin can inhibit gingipains, hemolytic, hemagglutination activities and biofilm formation at sub-MIC concentrations. Molecular docking analysis further indicated that quercetin can interact with gingipains. The biofilm became sparser and thinner after quercetin treatment. Quercetin also modulate cell surface hydrophobicity and aggregation. Expression of the genes tested was down-regulated in the presence of quercetin. In conclusion, our study demonstrated that quercetin inhibited various virulence factors of P. gingivalis.
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Prevotella intermedia produces two proteins homologous to Porphyromonas gingivalis HmuY but with different heme coordination mode. Biochem J 2020; 477:381-405. [PMID: 31899475 DOI: 10.1042/bcj20190607] [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: 08/21/2019] [Revised: 12/20/2019] [Accepted: 01/02/2020] [Indexed: 02/07/2023]
Abstract
As part of the infective process, Porphyromonas gingivalis must acquire heme which is indispensable for life and enables the microorganism to survive and multiply at the infection site. This oral pathogenic bacterium uses a newly discovered novel hmu heme uptake system with a leading role played by the HmuY hemophore-like protein, responsible for acquiring heme and increasing virulence of this periodontopathogen. We demonstrated that Prevotella intermedia produces two HmuY homologs, termed PinO and PinA. Both proteins were produced at higher mRNA and protein levels when the bacterium grew under low-iron/heme conditions. PinO and PinA bound heme, but preferentially under reducing conditions, and in a manner different from that of the P. gingivalis HmuY. The analysis of the three-dimensional structures confirmed differences between apo-PinO and apo-HmuY, mainly in the fold forming the heme-binding pocket. Instead of two histidine residues coordinating heme iron in P. gingivalis HmuY, PinO and PinA could use one methionine residue to fulfill this function, with potential support of additional methionine residue/s. The P. intermedia proteins sequestered heme only from the host albumin-heme complex under reducing conditions. Our findings suggest that HmuY-like family might comprise proteins subjected during evolution to significant diversification, resulting in different heme coordination modes. The newer data presented in this manuscript on HmuY homologs produced by P. intermedia sheds more light on the novel mechanism of heme uptake, could be helpful in discovering their biological function, and in developing novel therapeutic approaches.
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Porphyromonas gingivalis HmuY and Streptococcus gordonii GAPDH-Novel Heme Acquisition Strategy in the Oral Microbiome. Int J Mol Sci 2020; 21:ijms21114150. [PMID: 32532033 PMCID: PMC7312356 DOI: 10.3390/ijms21114150] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/02/2020] [Accepted: 06/08/2020] [Indexed: 12/13/2022] Open
Abstract
The oral cavity of healthy individuals is inhabited by commensals, with species of Streptococcus being the most abundant and prevalent in sites not affected by periodontal diseases. The development of chronic periodontitis is linked with the environmental shift in the oral microbiome, leading to the domination of periodontopathogens. Structure-function studies showed that Streptococcus gordonii employs a "moonlighting" protein glyceraldehyde-3-phosphate dehydrogenase (SgGAPDH) to bind heme, thus forming a heme reservoir for exchange with other proteins. Secreted or surface-associated SgGAPDH coordinates Fe(III)heme using His43. Hemophore-like heme-binding proteins of Porphyromonas gingivalis (HmuY), Prevotella intermedia (PinO) and Tannerella forsythia (Tfo) sequester heme complexed to SgGAPDH. Co-culturing of P. gingivalis with S. gordonii results in increased hmuY gene expression, indicating that HmuY might be required for efficient inter-bacterial interactions. In contrast to the DhmuY mutant strain, the wild type strain acquires heme and forms deeper biofilm structures on blood agar plates pre-grown with S. gordonii. Therefore, our novel paradigm of heme acquisition used by P. gingivalis appears to extend to co-infections with other oral bacteria and offers a mechanism for the ability of periodontopathogens to obtain sufficient heme in the host environment. Importantly, P. gingivalis is advantaged in terms of acquiring heme, which is vital for its growth survival and virulence.
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A large self-transmissible resistance plasmid from Nigeria contains genes that ameliorate a carrying cost. Sci Rep 2019; 9:19624. [PMID: 31873110 PMCID: PMC6927977 DOI: 10.1038/s41598-019-56064-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 12/02/2019] [Indexed: 02/06/2023] Open
Abstract
Antimicrobial resistance is rapidly expanding, in a large part due to mobile genetic elements. We screened 94 fecal fluoroquinolone-resistant Escherichia coli isolates from Nigeria for six plasmid-mediated quinolone resistance (PMQR) genes. Sixteen isolates harbored at least one of the PMQR genes and four were positive for aac-6-Ib-cr. In one strain, aac-6-Ib-cr was mapped to a 125 Kb self-transmissible IncFII plasmid, pMB2, which also bears blaCTX-M-15, seven other functional resistance genes and multiple resistance pseudogenes. Laboratory strains carrying pMB2 grew faster than isogenic strains lacking the plasmid in both rich and minimal media. We excised a 32 Kb fragment containing transporter genes and several open-reading frames of unknown function. The resulting 93 Kb mini-plasmid conferred slower growth rates and lower fitness than wildtype pMB2. Trans-complementing the deletion with the cloned sitABCD genes confirmed that they accounted for the growth advantage conferred by pMB2 in iron-depleted media. pMB2 is a large plasmid with a flexible resistance region that contains loci that can account for evolutionary success in the absence of antimicrobials. Ancillary functions conferred by resistance plasmids can mediate their retention and transmissibility, worsening the trajectory for antimicrobial resistance and potentially circumventing efforts to contain resistance through restricted use.
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Śmiga M, Olczak T. PgRsp Is a Novel Redox-Sensing Transcription Regulator Essential for Porphyromonas gingivalis Virulence. Microorganisms 2019; 7:microorganisms7120623. [PMID: 31795139 PMCID: PMC6955866 DOI: 10.3390/microorganisms7120623] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 11/20/2019] [Accepted: 11/25/2019] [Indexed: 12/14/2022] Open
Abstract
Porphyromonas gingivalis is one of the etiological agents of chronic periodontitis. Both heme and oxidative stress impact expression of genes responsible for its survival and virulence. Previously we showed that P. gingivalis ferric uptake regulator homolog affects expression of a gene encoding a putative Crp/Fnr superfamily member, termed P. gingivalis redox-sensing protein (PgRsp). Although PgRsp binds heme and shows the highest similarity to proteins assigned to the CooA family, it could be a member of a novel, separate family of proteins with unknown function. Expression of the pgrsp gene is autoregulated and iron/heme dependent. Genes encoding proteins engaged in the oxidative stress response were upregulated in the pgrsp mutant (TO11) strain compared with the wild-type strain. The TO11 strain showed higher biomass production, biofilm formation, and coaggregation ability with Tannerella forsythia and Prevotella intermedia. We suggest that PgRsp may regulate production of virulence factors, proteases, Hmu heme acquisition system, and FimA protein. Moreover, we observed growth retardation of the TO11 strain under oxidative conditions and decreased survival ability of the mutant cells inside macrophages. We conclude that PgRsp protein may play a role in the oxidative stress response using heme as a ligand for sensing changes in redox status, thus regulating the alternative pathway of the oxidative stress response alongside OxyR.
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Śmiga M, Bielecki M, Olczak M, Olczak T. Porphyromonas gingivalis PgFur Is a Member of a Novel Fur Subfamily With Non-canonical Function. Front Cell Infect Microbiol 2019; 9:233. [PMID: 31312617 PMCID: PMC6613475 DOI: 10.3389/fcimb.2019.00233] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 06/14/2019] [Indexed: 12/11/2022] Open
Abstract
Porphyromonas gingivalis, a keystone pathogen of chronic periodontitis, uses ferric uptake regulator homolog (PgFur) to regulate production of virulence factors. This study aimed to characterize PgFur protein in regard to its structure-function relationship. We experimentally identified the 5′ mRNA sequence encoding the 171-amino-acid-long PgFur protein in the A7436 strain and examined this PgFur version as a full-length protein. PgFur protein did not bind to the canonical Escherichia coli Fur box, but the wild-type phenotype of the mutant Δpgfur strain was restored partially when expression of the ecfur gene was induced from the native pgfur promoter. The full-length PgFur protein contained one zinc atom per protein monomer, but did not bind iron, manganese, or heme. Single cysteine substitutions of CXXC motifs resulted in phenotypes similar to the mutant Δpgfur strain. The modified proteins were produced in E. coli at significantly lower levels, were highly unstable, and did not bind zinc. The pgfur gene was expressed at the highest levels in bacteria cultured for 24 h in the absence of iron and heme or at higher levels in bacteria cultured for 10 h in the presence of protoporphyrin IX source. No influence of high availability of Fe2+, Zn2+, or Mn2+ on pgfur gene expression was observed. Two chromosomal mutant strains producing protein lacking 4 (pgfurΔ4aa) or 13 (pgfurΔ13aa) C-terminal amino acid residues were examined in regard to importance of the C-terminal lysine-rich region. The pgfurΔ13aa strain showed a phenotype typical for the mutant Δpgfur strain, but both the wild-type PgFur protein and its truncated version bound zinc with similar ability. The Δpgfur mutant strain produced higher amounts of HmuY protein compared with the wild-type strain, suggesting compromised regulation of its expression. Potential PgFur ligands, Fe2+, Mn2+, Zn2+, PPIX, or serum components, did not influence HmuY production in the Δpgfur mutant strain. The mutant pgfurΔ4aa and pgfurΔ13aa strains exhibited affected HmuY protein production. PgFur, regardless of the presence of the C-terminal lysine-rich region, bound to the hmu operon promoter. Our data suggest that cooperation of PgFur with partners/cofactors and/or protein/DNA modifications would be required to accomplish its role played in an in vivo multilayer regulatory network.
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Affiliation(s)
- Michał Śmiga
- Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
| | - Marcin Bielecki
- Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
| | - Mariusz Olczak
- Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
| | - Teresa Olczak
- Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
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Moradali MF, Ghods S, Angelini TE, Davey ME. Amino acids as wetting agents: surface translocation by Porphyromonas gingivalis. THE ISME JOURNAL 2019; 13:1560-1574. [PMID: 30783212 PMCID: PMC6775972 DOI: 10.1038/s41396-019-0360-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/11/2019] [Accepted: 01/17/2019] [Indexed: 02/06/2023]
Abstract
Our understanding of how oral microbiota adapt in response to changes in their surroundings remains limited. This is particularly true of the slow-growing anaerobes that persist below the gum line. Here, we report that the oral anaerobe Porphyromonas gingivalis strain 381 can surface translocate when sandwiched between two surfaces. We show that during movement, this bacterium alters its metabolism, specifically side products of arginine utilization including citrulline and ornithine accumulated in the translocating cells; while arginine, N-acetyl-arginine, and the polyamine putrescine, which is produced from arginine were consumed. In addition, our results indicate that movement requires modification of the surrounding environment via proteolysis, cell dispersion, cell-on-cell rolling, and sub-diffusive cell-driven motility. We also show that production of fimbriae and fimbriae-associated proteins; as well as the regulation of contact-dependent growth inhibition genes, which are known to be involved in self-nonself discrimination, and the type IX secretion system are central to surface translocation. These studies provide a first glimpse into P. gingivalis motility and its relationship to ecological variables.
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Affiliation(s)
- M Fata Moradali
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, 32610, USA
| | - Shirin Ghods
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, 32610, USA
| | - Thomas E Angelini
- Department of Mechanical & Aerospace Engineering, University of Florida, Gainesville, FL, 32610, USA
| | - Mary Ellen Davey
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, 32610, USA.
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Rocha ER, Bergonia HA, Gerdes S, Jeffrey Smith C. Bacteroides fragilis requires the ferrous-iron transporter FeoAB and the CobN-like proteins BtuS1 and BtuS2 for assimilation of iron released from heme. Microbiologyopen 2019; 8:e00669. [PMID: 29931811 PMCID: PMC6460266 DOI: 10.1002/mbo3.669] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/13/2018] [Accepted: 05/07/2018] [Indexed: 12/17/2022] Open
Abstract
The intestinal commensal and opportunistic anaerobic pathogen Bacteroides fragilis has an essential requirement for both heme and free iron to support growth in extraintestinal infections. In the absence of free iron, B. fragilis can utilize heme as the sole source of iron. However, the mechanisms to remove iron from heme are not completely understood. In this study, we show that the inner membrane ferrous iron transporter ∆feoAB mutant strain is no longer able to grow with heme as the sole source of iron. Genetic complementation with the feoAB gene operon completely restored growth. Our data indicate that iron is removed from heme in the periplasmic space, and the released iron is transported by the FeoAB system. Interestingly, when B. fragilis utilizes iron from heme, it releases heme-derived porphyrins by a dechelatase activity which is upregulated under low iron conditions. This is supported by the findings showing that formation of heme-derived porphyrins in the ∆feoAB mutant and the parent strain increased 30-fold and fivefold (respectively) under low iron conditions compared to iron replete conditions. Moreover, the btuS1 btuS2 double-mutant strain (lacking the predicted periplasmic, membrane anchored CobN-like proteins) also showed growth defect with heme as the sole source of iron, suggesting that BtuS1 and BtuS2 are involved in heme-iron assimilation. Though the dechelatase mechanism remains uncharacterized, assays performed in bacterial crude extracts show that BtuS1 and BtuS2 affect the regulation of the dechelatase-specific activities in an iron-dependent manner. These findings suggest that the mechanism to extract iron from heme in Bacteroides requires a group of proteins, which spans the periplasmic space to make iron available for cellular functions.
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Affiliation(s)
- Edson R. Rocha
- Department of Microbiology and ImmunologyBrody School of MedicineGreenvilleNorth Carolina
| | - Hector A. Bergonia
- Iron and Heme CoreDivision of HematologyUniversity of Utah School of MedicineSalt Lake CityUtah
| | | | - Charles Jeffrey Smith
- Department of Microbiology and ImmunologyBrody School of MedicineGreenvilleNorth Carolina
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Chao A, Sieminski PJ, Owens CP, Goulding CW. Iron Acquisition in Mycobacterium tuberculosis. Chem Rev 2018; 119:1193-1220. [PMID: 30474981 DOI: 10.1021/acs.chemrev.8b00285] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The highly contagious disease tuberculosis (TB) is caused by the bacterium Mycobacterium tuberculosis (Mtb), which has been evolving drug resistance at an alarming rate. Like all human pathogens, Mtb requires iron for growth and virulence. Consequently, Mtb iron transport is an emerging drug target. However, the development of anti-TB drugs aimed at these metabolic pathways has been restricted by the dearth of information on Mtb iron acquisition. In this Review, we describe the multiple strategies utilized by Mtb to acquire ferric iron and heme iron. Mtb iron uptake is a complex process, requiring biosynthesis and subsequent export of Mtb siderophores, followed by ferric iron scavenging and ferric-siderophore import into Mtb. Additionally, Mtb possesses two possible heme uptake pathways and an Mtb-specific mechanism of heme degradation that yields iron and novel heme-degradation products. We conclude with perspectives for potential therapeutics that could directly target Mtb heme and iron uptake machineries. We also highlight how hijacking Mtb heme and iron acquisition pathways for drug import may facilitate drug transport through the notoriously impregnable Mtb cell wall.
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Affiliation(s)
| | | | - Cedric P Owens
- Schmid College of Science and Technology , Chapman University , Orange , California 92866 , United States
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20
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Tannerella forsythia Tfo belongs to Porphyromonas gingivalis HmuY-like family of proteins but differs in heme-binding properties. Biosci Rep 2018; 38:BSR20181325. [PMID: 30266745 PMCID: PMC6200708 DOI: 10.1042/bsr20181325] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 09/10/2018] [Accepted: 09/20/2018] [Indexed: 12/16/2022] Open
Abstract
Porphyromonas gingivalis is considered the principal etiologic agent and keystone pathogen of chronic periodontitis. As an auxotrophic bacterium, it must acquire heme to survive and multiply at the infection site. P. gingivalis HmuY is the first member of a novel family of hemophore-like proteins. Bacterial heme-binding proteins usually use histidine-methionine or histidine-tyrosine residues to ligate heme-iron, whereas P. gingivalis HmuY uses two histidine residues. We hypothesized that other 'red complex' members, i.e. Tannerella forsythia and Treponema denticola might utilize similar heme uptake mechanisms to the P. gingivalis HmuY. Comparative and phylogenetic analyses suggested differentiation of HmuY homologs and low conservation of heme-coordinating histidine residues present in HmuY. The homologs were subjected to duplication before divergence of Bacteroidetes lineages, which could facilitate evolution of functional diversification. We found that T. denticola does not code an HmuY homolog. T. forsythia protein, termed as Tfo, binds heme, but preferentially in the ferrous form, and sequesters heme from the albumin-heme complex under reducing conditions. In agreement with that, the 3D structure of Tfo differs from that of HmuY in the folding of heme-binding pocket, containing two methionine residues instead of two histidine residues coordinating heme in HmuY. Heme binding to apo-HmuY is accompanied by movement of the loop carrying the His166 residue, closing the heme-binding pocket. Molecular dynamics simulations (MD) demonstrated that this conformational change also occurs in Tfo. In conclusion, our findings suggest that HmuY-like family might comprise proteins subjected during evolution to significant diversification, resulting in different heme-binding properties.
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21
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Abdelhamed H, Ibrahim I, Baumgartner W, Lawrence ML, Karsi A. The virulence and immune protection of Edwardsiella ictaluri HemR mutants in catfish. FISH & SHELLFISH IMMUNOLOGY 2018; 72:153-160. [PMID: 29097322 DOI: 10.1016/j.fsi.2017.10.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 10/21/2017] [Accepted: 10/24/2017] [Indexed: 06/07/2023]
Abstract
Edwardsiella ictaluri is a Gram-negative facultative intracellular rod, causing enteric septicemia of catfish (ESC). Several heme uptake systems have been described in bacterial pathogens, most of which involve outer membrane proteins (OMPs). We have shown recently that heme/hemoglobin receptor family protein (HemR) is significantly up-regulated in E. ictaluri under iron-restricted conditions. In this work, our goal was to construct E. ictaluri HemR mutants and assess their virulence and immune protection potentials in catfish. To accomplish this, an in-frame deletion mutant (EiΔhemR) was constructed, and its virulence and immune protection were determined in catfish fingerlings and fry. The results indicated that the EiΔhemR was attenuated completely in catfish fingerlings, but it was virulent in 14 day-old catfish fry. To increase the attenuation of EiΔhemR in fry, we introduced frdA and sdhC gene deletions to the mutant, yielding two double (EiΔhemRΔfrdA and EiΔhemRΔsdhC) and one triple (EiΔhemRΔfrdAΔsdhC) mutants. Results indicated that two double HemR mutants did not exhibit increased attenuation, but the triple HemR mutant showed significantly less virulence and high protection in fry (p < 0.05). Histological examination of fry tissues vaccinated with the triple mutant displayed similar inflammation to that of wild-type infected fry, but much less necrosis and far fewer bacteria were observed. Immunohistochemistry (IHC) result indicated fewer numbers of bacteria around blood vessel and in the hematopoietic tissue in fry infected with triple mutant compared to control group infected with E. ictaluri wild-type. Our data indicated that EiΔhemR was safe and protective in catfish fingerlings, while EiΔhemRΔfrdAΔsdhC was much safer in catfish fry.
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Affiliation(s)
- Hossam Abdelhamed
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Iman Ibrahim
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA; Department of Pathology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Dakahlia 35516, Egypt
| | - Wes Baumgartner
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Mark L Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA.
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Rangarajan M, Aduse‐Opoku J, Paramonov N, Hashim A, Curtis M. Hemin binding by Porphyromonas gingivalis strains is dependent on the presence of A-LPS. Mol Oral Microbiol 2017; 32:365-374. [PMID: 28107612 PMCID: PMC5600137 DOI: 10.1111/omi.12178] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2017] [Indexed: 11/29/2022]
Abstract
Porphyromonas gingivalis is a Gram-negative black pigmenting anaerobe that is unable to synthesize heme [Fe(II)-protoporphyrin IX] or hemin [Fe(III)-protoporphyrin IX-Cl], which are important growth/virulence factors, and must therefore derive them from the host. Porphyromonas gingivalis expresses several proteinaceous hemin-binding sites, which are important in the binding/transport of heme/hemin from the host. It also synthesizes several virulence factors, namely cysteine-proteases Arg- and Lys-gingipains and two lipopolysaccharides (LPS), O-LPS and A-LPS. The gingipains are required for the production of the black pigment, μ-oxo-bisheme {[Fe(III)PPIX]2 O}, which is derived from hemoglobin and deposited on the bacterial cell-surface leading to the characteristic black colonies when grown on blood agar. In this study we investigated the role of LPS in the deposition of μ-oxo-bisheme on the cell-surface. A P. gingivalis mutant defective in the biosynthesis of Arg-gingipains, namely rgpA/rgpB, produces brown colonies on blood agar and mutants defective in Lys-gingipain (kgp) and LPS biosynthesis namely porR, waaL, wzy, and pg0129 (α-1, 3-mannosyltransferase) produce non-pigmented colonies. However, only those mutants lacking A-LPS showed reduced hemin-binding when cells in suspension were incubated with hemin. Using native, de-O-phosphorylated and de-lipidated LPS from P. gingivalis W50 and porR strains, we demonstrated that hemin-binding to O-polysaccharide (PS) and to the lipid A moiety of LPS was reduced compared with hemin-binding to A-PS. We conclude that A-LPS in the outer-membrane of P. gingivalis serves as a scaffold/anchor for the retention of μ-oxo-bisheme on the cell surface and pigmentation is dependent on the presence of A-LPS.
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Affiliation(s)
- M. Rangarajan
- Institute of DentistryBarts and The London School of Medicine & DentistryQueen Mary University of LondonLondonUK
| | - J. Aduse‐Opoku
- Institute of DentistryBarts and The London School of Medicine & DentistryQueen Mary University of LondonLondonUK
| | - N.A. Paramonov
- Institute of DentistryBarts and The London School of Medicine & DentistryQueen Mary University of LondonLondonUK
| | - A. Hashim
- Institute of DentistryBarts and The London School of Medicine & DentistryQueen Mary University of LondonLondonUK
- College of DentistryKing Faisal UniversityAl‐AhsaSaudi Arabia
| | - M.A. Curtis
- Institute of DentistryBarts and The London School of Medicine & DentistryQueen Mary University of LondonLondonUK
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Guo Y, Hu D, Guo J, Li X, Guo J, Wang X, Xiao Y, Jin H, Liu M, Li Z, Bi D, Zhou Z. The Role of the Regulator Fur in Gene Regulation and Virulence of Riemerella anatipestifer Assessed Using an Unmarked Gene Deletion System. Front Cell Infect Microbiol 2017; 7:382. [PMID: 28971067 PMCID: PMC5609570 DOI: 10.3389/fcimb.2017.00382] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 08/09/2017] [Indexed: 11/29/2022] Open
Abstract
Riemerella anatipestifer, an avian pathogen, has resulted in enormous economic losses to the duck industry globally. Notwithstanding, little is known regarding the physiological, pathogenic and virulence mechanisms of Riemerella anatipestifer (RA) infection. However, the role of Ferric uptake regulator (Fur) in the virulence of R. anatipestifer has not, to date, been demonstrated. Using a genetic approach, unmarked gene deletion system, we evaluated the function of fur gene in the virulence of R. anatipestifer. For this purpose, we constructed a suicide vector containing pheS as a counter selectable marker for unmarked deletion of fur gene to investigate its role in the virulence. After successful transformation of the newly constructed vector, a mutant strain was characterized for genes regulated by iron and Fur using RNA-sequencing and a comparison was made between wild type and mutant strains in both iron restricted and enriched conditions. RNA-seq analysis of the mutant strain in a restricted iron environment showed the downregulation and upregulation of genes which were involved in either important metabolic pathways, transport processes, growth or cell membrane synthesis. Electrophoretic mobility shift assay was performed to identify the putative sequences recognized by Fur. The putative Fur-box sequence was 5′-GATAATGATAATCATTATC-3′. Lastly, the median lethal dose and histopathological investigations of animal tissues also illustrated mild pathological lesions produced by the mutant strain as compared to the wild type RA strain, hence showing declined virulence. Conclusively, an unmarked gene deletion system was successfully developed for RA and the role of the fur gene in virulence was explored comprehensively.
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Affiliation(s)
- Yunqing Guo
- College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China.,Key Lab of Preventive Veterinary Medicine of Hubei Province, Huazhong Agricultural UniversityWuhan, China
| | - Di Hu
- College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China.,Key Lab of Preventive Veterinary Medicine of Hubei Province, Huazhong Agricultural UniversityWuhan, China
| | - Jie Guo
- College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China.,Key Lab of Preventive Veterinary Medicine of Hubei Province, Huazhong Agricultural UniversityWuhan, China
| | - Xiaowen Li
- College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China.,Key Lab of Preventive Veterinary Medicine of Hubei Province, Huazhong Agricultural UniversityWuhan, China
| | - Jinyue Guo
- College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China.,Key Lab of Preventive Veterinary Medicine of Hubei Province, Huazhong Agricultural UniversityWuhan, China
| | - Xiliang Wang
- College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China.,Key Lab of Preventive Veterinary Medicine of Hubei Province, Huazhong Agricultural UniversityWuhan, China
| | - Yuncai Xiao
- College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China.,Key Lab of Preventive Veterinary Medicine of Hubei Province, Huazhong Agricultural UniversityWuhan, China
| | - Hui Jin
- College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China.,State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural UniversityWuhan, China
| | - Mei Liu
- College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China.,Key Lab of Preventive Veterinary Medicine of Hubei Province, Huazhong Agricultural UniversityWuhan, China
| | - Zili Li
- College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China.,Key Lab of Preventive Veterinary Medicine of Hubei Province, Huazhong Agricultural UniversityWuhan, China
| | - Dingren Bi
- College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China.,Key Lab of Preventive Veterinary Medicine of Hubei Province, Huazhong Agricultural UniversityWuhan, China.,State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural UniversityWuhan, China
| | - Zutao Zhou
- College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China.,Key Lab of Preventive Veterinary Medicine of Hubei Province, Huazhong Agricultural UniversityWuhan, China
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Abstract
Iron is an essential micronutrient for both microbes and humans alike. For well over half a century we have known that this element, in particular, plays a pivotal role in health and disease and, most especially, in shaping host-pathogen interactions. Intracellular iron concentrations serve as a critical signal in regulating the expression not only of high-affinity iron acquisition systems in bacteria, but also of toxins and other noted virulence factors produced by some major human pathogens. While we now are aware of many strategies that the host has devised to sequester iron from invading microbes, there are as many if not more sophisticated mechanisms by which successful pathogens overcome nutritional immunity imposed by the host. This review discusses some of the essential components of iron sequestration and scavenging mechanisms of the host, as well as representative Gram-negative and Gram-positive pathogens, and highlights recent advances in the field. Last, we address how the iron acquisition strategies of pathogenic bacteria may be exploited for the development of novel prophylactics or antimicrobials.
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Using Tn-seq To Identify Pigmentation-Related Genes of Porphyromonas gingivalis: Characterization of the Role of a Putative Glycosyltransferase. J Bacteriol 2017; 199:JB.00832-16. [PMID: 28484050 DOI: 10.1128/jb.00832-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 05/04/2017] [Indexed: 11/20/2022] Open
Abstract
Cellular pigmentation is an important virulence factor of the oral pathogen Porphyromonas gingivalis Pigmentation has been associated with many bacterial functions, including but not limited to colonization, maintaining a local anaerobic environment by binding oxygen molecules, and defense against reactive oxygen species (ROS) produced by immune cells. Pigmentation-associated loci identified to date have involved lipopolysaccharide, fimbriae, and heme acquisition and processing. We utilized a transposon mutant library of P. gingivalis strain ATCC 33277 and screened for pigmentation-defective colonies using massively parallel sequencing of the transposon junctions (Tn-seq) to identify genes involved in pigmentation. Transposon insertions at 235 separate sites, located in 67 genes and 15 intergenic regions, resulted in altered pigmentation: 7 of the genes had previously been shown to be involved in pigmentation, while 75 genes and intergenic regions had not. To further confirm identification, we generated a smaller transposon mutant library in P. gingivalis strain W83 and identified pigment mutations in several of the same loci as those identified in the screen in ATCC 33277 but also eight that were not identified in the ATCC 33277 screen. PGN_0361/PG_0264, a putative glycosyltransferase gene located between two tRNA synthetase genes and adjacent to a miniature inverted-repeat transposable element, was identified in the Tn-seq screen and then verified through targeted deletion and complementation. Deletion mutations in PGN_0361/PG_0264 glycosyltransferase abolish pigmentation, modulate gingipain protease activity, and alter lipopolysaccharide. The mechanisms of involvement in pigmentation for other loci identified in this study remain to be determined, but our screen provides the most complete survey of genes involved in pigmentation to date.IMPORTANCEP. gingivalis has been implicated in the onset and progression of periodontal disease. One important virulence factor is the bacterium's ability to produce pigment. Using a transposon library, we were able to identify both known and novel genes involved in pigmentation of P. gingivalis We identified a glycosyltransferase, previously not associated with pigmentation, that is required for pigmentation and determined its mechanism of involvement. A better understanding of the genes involved in pigmentation may lead to new insights into the complex mechanisms involved in this important virulence characteristic and could facilitate development of novel therapeutics.
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Brewitz HH, Hagelueken G, Imhof D. Structural and functional diversity of transient heme binding to bacterial proteins. Biochim Biophys Acta Gen Subj 2017; 1861:683-697. [DOI: 10.1016/j.bbagen.2016.12.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 12/15/2016] [Accepted: 12/20/2016] [Indexed: 11/27/2022]
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Wang M, Zhang P, Zhu D, Wang M, Jia R, Chen S, Sun K, Yang Q, Wu Y, Chen X, Biville F, Cheng A, Liu M. Identification of the ferric iron utilization gene B739_1208 and its role in the virulence of R. anatipestifer CH-1. Vet Microbiol 2017; 201:162-169. [PMID: 28284604 DOI: 10.1016/j.vetmic.2017.01.027] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 01/12/2017] [Accepted: 01/23/2017] [Indexed: 10/20/2022]
Abstract
Riemerella anatipestifer is an important bacterial pathogen in ducks and causes heavy economic losses in the duck industry. However, the pathogensis of this bacterium is poorly understood. In this study, a putative outer membrane hemin receptor gene B739_1208 in R. anatipestifer CH-1 was deleted to determine the relationship between iron uptake and virulence. The R. anatipestifer CH-1ΔB739_1208 mutants grew significantly more slowly than the wild-type bacteria in TSB liquid medium. Further characterization revealed that the R. anatipestifer CH-1ΔB739_1208 mutants were deficient in iron uptake. Animal experiments indicated that the median lethal dose of the wild-type RA-CH-1 in ducklings was 3.89×108, whereas the median lethal dose of the R. anatipestifer CH-1ΔB739_1208 mutant in ducklings was 5.68×109. The median lethal dose of the complementation strain in ducklings was 9.84×108. Additional analysis indicated that bacterial loads in the blood, liver, and brain tissues in the R. anatipestifer CH-1ΔB739_1208-infected ducklings were significantly decreased compared to those in the wild-type R. anatipestifer CH-1 infected ducklings. In a duck co-infection model with R. anatipestifer CH-1 and R. anatipestifer CH-1ΔB739_1208, the R. anatipestifer CH-1B739_1208 mutant was outcompeted by the wild-type R. anatipestifer CH-1 in the blood (P<0.002), livers (P<0.001) and brains (P<0.001) of infected ducks, indicating that B739_1208 gene expression provided a competitive advantage in these organs. Our results demonstrate that the B739_1208 gene is a virulence factor in R. anatipestifer CH-1.
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Affiliation(s)
- MengYi Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Research Center of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - PengYun Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Research Center of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - DeKang Zhu
- Research Center of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - MingShu Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Research Center of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - RenYong Jia
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Research Center of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Shun Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Research Center of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - KunFeng Sun
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Research Center of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Qiao Yang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Research Center of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Ying Wu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Research Center of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - XiaoYue Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Research Center of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Francis Biville
- Unité des Infections Bactériennes Invasives, Département Infection et Epidémiologie, Institut Pasteur, Paris, France
| | - AnChun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Research Center of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China.
| | - MaFeng Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Research Center of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China.
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SigCH, an extracytoplasmic function sigma factor of Porphyromonas gingivalis regulates the expression of cdhR and hmuYR. Anaerobe 2016; 43:82-90. [PMID: 27940243 DOI: 10.1016/j.anaerobe.2016.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Revised: 11/16/2016] [Accepted: 12/05/2016] [Indexed: 12/25/2022]
Abstract
Extracytoplasmic function (ECF) sigma factors play an important role in the bacterial response to various environmental stresses. Porphyromonas gingivalis, a prominent etiological agent in human periodontitis, possesses six putative ECF sigma factors. So far, information is limited on the ECF sigma factor, PGN_0319. The aim of this study was to investigate the role of PGN_0319 (SigCH) of P. gingivalis, focusing on the regulation of hmuY and hmuR, which encode outer-membrane proteins involved in hemin utilization, and cdhR, a transcriptional regulator of hmuYR. First, we evaluated the gene expression profile of the sigCH mutant by DNA microarray. Among the genes with altered expression levels, those involved in hemin utilization were downregulated in the sigCH mutant. To verify the microarray data, quantitative reverse transcription PCR analysis was performed. The RNA samples used were obtained from bacterial cells grown to early-log phase, in which sigCH expression in the wild type was significantly higher than that in mid-log and late-log phases. The expression levels of hmuY, hmuR, and cdhR were significantly decreased in the sigCH mutant compared to wild type. Transcription of these genes was restored in a sigCH complemented strain. Compared to the wild type, the sigCH mutant showed reduced growth in log phase under hemin-limiting conditions. Electrophoretic mobility shift assays showed that recombinant SigCH protein bound to the promoter region of hmuY and cdhR. These results suggest that SigCH plays an important role in the early growth of P. gingivalis, and directly regulates cdhR and hmuYR, thereby playing a potential role in the mechanisms of hemin utilization by P. gingivalis.
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29
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Romero-Espejel ME, Rodríguez MA, Chávez-Munguía B, Ríos-Castro E, Olivares-Trejo JDJ. Characterization of Spbhp-37, a Hemoglobin-Binding Protein of Streptococcus pneumoniae. Front Cell Infect Microbiol 2016; 6:47. [PMID: 27200302 PMCID: PMC4854876 DOI: 10.3389/fcimb.2016.00047] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 04/12/2016] [Indexed: 01/05/2023] Open
Abstract
Streptococcus pneumoniae is a Gram-positive microorganism that is the cause of bacterial pneumonia, sinusitis and otitis media. This human pathogen also can cause invasive diseases such as meningitis, bacteremia and septicemia. Hemoglobin (Hb) and haem can support the growth and viability of S. pneumoniae as sole iron sources. Unfortunately, the acquisition mechanism of Hb and haem in this bacterium has been poorly studied. Previously we identified two proteins of 37 and 22 kDa as putative Hb- and haem-binding proteins (Spbhp-37 and Spbhp-22, respectively). The sequence of Spbhp-37 protein was database annotated as lipoprotein without any function or localization. Here it was immunolocalized in the surface cell by transmission electron microscopy using specific antibodies produced against the recombinant protein. The expression of Spbhp-37 was increased when bacteria were grown in media culture supplied with Hb. In addition, the affinity of Sphbp-37 for Hb was determined. Thus, in this work we are presenting new findings that attempt to explain the mechanism involved in iron acquisition of this pathogen. In the future these results could help to develop new therapy targets in order to avoid the secondary effects caused by the traditional therapies.
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Affiliation(s)
- María E Romero-Espejel
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN México, México
| | - Mario A Rodríguez
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN México, México
| | - Bibiana Chávez-Munguía
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN México, México
| | - Emmanuel Ríos-Castro
- Unidad de Genómica, Proteómica y Metabolómica. LaNSE-CINVESTAV, Centro de Investigación y de Estudios Avanzados del IPN México, México
| | - José de Jesús Olivares-Trejo
- Laboratorio de Bacteriología y Nanomedicina, Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México México, México
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Smalley JW, Olczak T. Heme acquisition mechanisms of Porphyromonas gingivalis - strategies used in a polymicrobial community in a heme-limited host environment. Mol Oral Microbiol 2016; 32:1-23. [PMID: 26662717 DOI: 10.1111/omi.12149] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2015] [Indexed: 01/14/2023]
Abstract
Porphyromonas gingivalis, a main etiologic agent and key pathogen responsible for initiation and progression of chronic periodontitis requires heme as a source of iron and protoporphyrin IX for its survival and the ability to establish an infection. Porphyromonas gingivalis is able to accumulate a defensive cell-surface heme-containing pigment in the form of μ-oxo bisheme. The main sources of heme for P. gingivalis in vivo are hemoproteins present in saliva, gingival crevicular fluid, and erythrocytes. To acquire heme, P. gingivalis uses several mechanisms. Among them, the best characterized are those employing hemagglutinins, hemolysins, and gingipains (Kgp, RgpA, RgpB), TonB-dependent outer-membrane receptors (HmuR, HusB, IhtA), and hemophore-like proteins (HmuY, HusA). Proteins involved in intracellular heme transport, storage, and processing are less well characterized (e.g. PgDps). Importantly, P. gingivalis may also use the heme acquisition systems of other bacteria to fulfill its own heme requirements. Porphyromonas gingivalis displays a novel paradigm for heme acquisition from hemoglobin, whereby the Fe(II)-containing oxyhemoglobin molecule must first be oxidized to methemoglobin to facilitate heme release. This process not only involves P. gingivalis arginine- and lysine-specific gingipains, but other proteases (e.g. interpain A from Prevotella intermedia) or pyocyanin produced by Pseudomonas aeruginosa. Porphyromonas gingivalis is then able to fully proteolyze the more susceptible methemoglobin substrate to release free heme or to wrest heme from it directly through the use of the HmuY hemophore.
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Affiliation(s)
- J W Smalley
- School of Dentistry, University of Liverpool, Liverpool, UK
| | - T Olczak
- Laboratory of Biochemistry, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
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Gui MJ, Dashper SG, Slakeski N, Chen YY, Reynolds EC. Spheres of influence: Porphyromonas gingivalis outer membrane vesicles. Mol Oral Microbiol 2015; 31:365-78. [PMID: 26466922 DOI: 10.1111/omi.12134] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2015] [Indexed: 12/15/2022]
Abstract
Outer membrane vesicles (OMVs) are asymmetrical single bilayer membranous nanostructures produced by Gram-negative bacteria important for bacterial interaction with the environment. Porphyromonas gingivalis, a keystone pathogen associated with chronic periodontitis, produces OMVs that act as a virulence factor secretion system contributing to its pathogenicity. Despite their biological importance, the mechanisms of OMV biogenesis have not been fully elucidated. The ~14 times more curvature of the OMV membrane than cell outer membrane (OM) indicates that OMV biogenesis requires energy expenditure for significant curvature of the OMV membrane. In P. gingivalis, we propose that this may be achieved by upregulating the production of certain inner or outer leaflet lipids, which causes localized outward curvature of the OM. This results in selection of anionic lipopolysaccharide (A-LPS) and associated C-terminal domain (CTD) -family proteins on the outer surface due to their ability to accommodate the curvature. Deacylation of A-LPS may further enable increased curvature leading to OMV formation. Porphyromonas gingivalis OMVs that are selectively enriched in CTD-family proteins, largely the gingipains, can support bacterial coaggregation, promote biofilm development and act as an intercessor for the transport of non-motile bacteria by motile bacteria. The P. gingivalis OMVs are also believed to contribute to host interaction and colonization, evasion of immune defense mechanisms, and destruction of periodontal tissues. They may be crucial for both micro- and macronutrient capture, especially heme and probably other assimilable compounds for its own benefit and that of the wider biofilm community.
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Affiliation(s)
- M J Gui
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria, Vic, Australia
| | - S G Dashper
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria, Vic, Australia
| | - N Slakeski
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria, Vic, Australia
| | - Y-Y Chen
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria, Vic, Australia
| | - E C Reynolds
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria, Vic, Australia
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Yang Q, Yu F, Sun L, Zhang Q, Lin M, Geng X, Sun X, Li J, Liu Y. Identification of amino acid residues involved in hemin binding inPorphyromonas gingivalishemagglutinin 2. Mol Oral Microbiol 2015; 30:337-46. [PMID: 25833325 DOI: 10.1111/omi.12097] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2015] [Indexed: 12/01/2022]
Affiliation(s)
- Q.B. Yang
- Beijing Institute for Dental Research; Beijing Stomatological Hospital and School of Stomatology; Capital Medical University; Beijing China
| | - F.Y. Yu
- Beijing Institute for Dental Research; Beijing Stomatological Hospital and School of Stomatology; Capital Medical University; Beijing China
| | - L. Sun
- Beijing Institute for Dental Research; Beijing Stomatological Hospital and School of Stomatology; Capital Medical University; Beijing China
| | - Q.X. Zhang
- Beijing Institute for Dental Research; Beijing Stomatological Hospital and School of Stomatology; Capital Medical University; Beijing China
| | - M. Lin
- Beijing Institute for Dental Research; Beijing Stomatological Hospital and School of Stomatology; Capital Medical University; Beijing China
| | - X.Y. Geng
- Beijing Institute for Dental Research; Beijing Stomatological Hospital and School of Stomatology; Capital Medical University; Beijing China
| | - X.N. Sun
- Beijing Institute for Dental Research; Beijing Stomatological Hospital and School of Stomatology; Capital Medical University; Beijing China
| | - J.L. Li
- Beijing Institute for Dental Research; Beijing Stomatological Hospital and School of Stomatology; Capital Medical University; Beijing China
| | - Y. Liu
- Beijing Institute for Dental Research; Beijing Stomatological Hospital and School of Stomatology; Capital Medical University; Beijing China
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Butler CA, Dashper SG, Khan HS, Zhang L, Reynolds EC. The interplay between iron, haem and manganese in Porphyromonas gingivalis. J Oral Biosci 2015. [DOI: 10.1016/j.job.2014.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Pardesi B, Tompkins GR. Colony polymerase chain reaction of heme-accumulating bacteria. Anaerobe 2015; 32:49-50. [DOI: 10.1016/j.anaerobe.2014.11.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 11/19/2014] [Accepted: 11/23/2014] [Indexed: 11/26/2022]
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Ciuraszkiewicz J, Śmiga M, Mackiewicz P, Gmiterek A, Bielecki M, Olczak M, Olczak T. Fur homolog regulatesPorphyromonas gingivalisvirulence under low-iron/heme conditions through a complex regulatory network. Mol Oral Microbiol 2014; 29:333-53. [DOI: 10.1111/omi.12077] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2014] [Indexed: 12/22/2022]
Affiliation(s)
- J. Ciuraszkiewicz
- Laboratory of Biochemistry; Faculty of Biotechnology; University of Wroclaw; Wroclaw Poland
| | - M. Śmiga
- Laboratory of Biochemistry; Faculty of Biotechnology; University of Wroclaw; Wroclaw Poland
| | - P. Mackiewicz
- Department of Genomics; Faculty of Biotechnology; University of Wroclaw; Wroclaw Poland
| | - A. Gmiterek
- Laboratory of Biochemistry; Faculty of Biotechnology; University of Wroclaw; Wroclaw Poland
| | - M. Bielecki
- Laboratory of Biochemistry; Faculty of Biotechnology; University of Wroclaw; Wroclaw Poland
| | - M. Olczak
- Laboratory of Biochemistry; Faculty of Biotechnology; University of Wroclaw; Wroclaw Poland
| | - T. Olczak
- Laboratory of Biochemistry; Faculty of Biotechnology; University of Wroclaw; Wroclaw Poland
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Vázquez-Zamorano ZE, González-López MA, Romero-Espejel ME, Azuara-Liceaga EI, López-Casamichana M, Olivares-Trejo JDJ. Streptococcus pneumoniae secretes a glyceraldehyde-3-phosphate dehydrogenase, which binds haemoglobin and haem. Biometals 2014; 27:683-93. [DOI: 10.1007/s10534-014-9757-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 06/02/2014] [Indexed: 11/28/2022]
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Insights on how the Mycobacterium tuberculosis heme uptake pathway can be used as a drug target. Future Med Chem 2014; 5:1391-403. [PMID: 23919550 DOI: 10.4155/fmc.13.109] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Mycobacterium tuberculosis (Mtb) acquires non-heme iron through salicylate-derived siderophores termed mycobactins whereas heme iron is obtained through a cascade of heme uptake proteins. Three proteins are proposed to mediate Mtb heme iron uptake, a secreted heme transporter (Rv0203), and MmpL3 and MmpL11, which are potential transmembrane heme transfer proteins. Furthermore, MhuD, a cytoplasmic heme-degrading enzyme, has been identified. Rv0203, MmpL3 and MmpL11 are mycobacteria-specific proteins, making them excellent drug targets. Importantly, MmpL3, a necessary protein, has also been implicated in trehalose monomycolate export. Recent drug-discovery efforts revealed that MmpL3 is the target of several compounds with antimycobacterial activity. Inhibition of the Mtb heme uptake pathway has yet to be explored. We propose that inhibitor design could focus on heme analogs, with the goal of blocking specific steps of this pathway. In addition, heme uptake could be hijacked as a method of importing drugs into the mycobacterial cytosol.
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Differential roles of tryptophan residues in conformational stability of Porphyromonas gingivalis HmuY hemophore. BMC BIOCHEMISTRY 2014; 15:2. [PMID: 24512694 PMCID: PMC3922309 DOI: 10.1186/1471-2091-15-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 02/03/2014] [Indexed: 12/05/2022]
Abstract
Background We have previously shown that the P. gingivalis HmuY hemophore-like protein binds heme and scavenges heme from host hemoproteins to further deliver it to the cognate heme receptor HmuR. The aim of this study was to characterize structural features of HmuY variants in the presence and absence of heme with respect to roles of tryptophan residues in conformational stability. Results HmuY possesses tryptophan residues at positions 51 and 73, which are conserved in HmuY homologs present in a variety of bacteria, and a tryptophan residue at position 161, which has been found only in HmuY identified in P. gingivalis strains. We expressed and purified the wildtype HmuY and its protein variants with single tryptophan residues replaced by alanine or tyrosine residues. All HmuY variants were subjected to thermal denaturation and fluorescence spectroscopy analyses. Replacement of the most buried W161 only moderately affects protein stability. The most profound effect of the lack of a large hydrophobic side chain in respect to thermal stability is observed for W73. Also replacement of the W51 exposed on the surface results in the greatest loss of protein stability and even the large aromatic side chain of a tyrosine residue has little potential to substitute this tryptophan residue. Heme binding leads to different exposure of the tryptophan residue at position 51 to the surface of the protein. Differences in structural stability of HmuY variants suggest the change of the tertiary structure of the protein upon heme binding. Conclusions Here we demonstrate differential roles of tryptophan residues in the protein conformational stability. We also propose different conformations of apo- and holoHmuY caused by tertiary changes which allow heme binding to the protein.
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Caza M, Kronstad JW. Shared and distinct mechanisms of iron acquisition by bacterial and fungal pathogens of humans. Front Cell Infect Microbiol 2013; 3:80. [PMID: 24312900 PMCID: PMC3832793 DOI: 10.3389/fcimb.2013.00080] [Citation(s) in RCA: 178] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Accepted: 10/30/2013] [Indexed: 12/12/2022] Open
Abstract
Iron is the most abundant transition metal in the human body and its bioavailability is stringently controlled. In particular, iron is tightly bound to host proteins such as transferrin to maintain homeostasis, to limit potential damage caused by iron toxicity under physiological conditions and to restrict access by pathogens. Therefore, iron acquisition during infection of a human host is a challenge that must be surmounted by every successful pathogenic microorganism. Iron is essential for bacterial and fungal physiological processes such as DNA replication, transcription, metabolism, and energy generation via respiration. Hence, pathogenic bacteria and fungi have developed sophisticated strategies to gain access to iron from host sources. Indeed, siderophore production and transport, iron acquisition from heme and host iron-containing proteins such as hemoglobin and transferrin, and reduction of ferric to ferrous iron with subsequent transport are all strategies found in bacterial and fungal pathogens of humans. This review focuses on a comparison of these strategies between bacterial and fungal pathogens in the context of virulence and the iron limitation that occurs in the human body as a mechanism of innate nutritional defense.
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Affiliation(s)
| | - James W. Kronstad
- The Michael Smith Laboratories, Department of Microbiology and Immunology, University of British ColumbiaVancouver, BC, Canada
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Runyen-Janecky LJ. Role and regulation of heme iron acquisition in gram-negative pathogens. Front Cell Infect Microbiol 2013; 3:55. [PMID: 24116354 PMCID: PMC3792355 DOI: 10.3389/fcimb.2013.00055] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 09/10/2013] [Indexed: 12/14/2022] Open
Abstract
Bacteria that reside in animal tissues and/or cells must acquire iron from their host. However, almost all of the host iron is sequestered in iron-containing compounds and proteins, the majority of which is found within heme molecules. Thus, likely iron sources for bacterial pathogens (and non-pathogenic symbionts) are free heme and heme-containing proteins. Furthermore, the cellular location of the bacterial within the host (intra or extracellular) influences the amount and nature of the iron containing compounds available for transport. The low level of free iron in the host, coupled with the presence of numerous different heme sources, has resulted in a wide range of high-affinity iron acquisition strategies within bacteria. However, since excess iron and heme are toxic to bacteria, expression of these acquisition systems is highly regulated. Precise expression in the correct host environment at the appropriate times enables heme iron acquisitions systems to contribute to the growth of bacterial pathogens within the host. This mini-review will highlight some of the recent findings in these areas for gram-negative pathogens.
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Lu F, Miao S, Tu J, Ni X, Xing L, Yu H, Pan L, Hu Q. The role of TonB-dependent receptor TbdR1 in Riemerella anatipestifer in iron acquisition and virulence. Vet Microbiol 2013; 167:713-8. [PMID: 24075356 DOI: 10.1016/j.vetmic.2013.08.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Revised: 08/22/2013] [Accepted: 08/24/2013] [Indexed: 10/26/2022]
Abstract
Riemerella anatipestifer is an important duck pathogen and causes serious economic losses to the duck industry worldwide. To date, four full R. anatipestifer genomic sequences have been submitted to the GenBank database and 31 TonB-dependent outer membrane receptors, which may play critical roles in host-bacteria interactions, were predicted for R. anatipestifer strain GSM15868. In our previous study, we reported that the TonB-dependent receptor TbdR1 was a cross immunogenic antigen among R. anatipestifer serotypes 1, 2, and 10. However, the biological functions of TbdR1 in R. anatipestifer remain unclear. In the present study, a tbdR1 (Riean_1607) deletion mutant CH3ΔtbdR1 of R. anatipestifer strain CH3 was constructed and characterized for iron-limited growth, biofilm formation, and pathogenicity to ducklings. Our results showed that TbdR1 was involved in hemin iron acquisition and the tbdR1 deletion significantly reduced biofilm formation and adhesion to and invasion of Vero cells. Animal experiments indicated that the median lethal dose of the CH3ΔtbdR1 mutant in ducklings was about 45-fold higher than that of the wild-type CH3 strain. Additional analysis indicated that bacterial loads in blood, liver, and brain tissues in CH3ΔtbdR1-infected ducklings were decreased significantly compared to those in wild-type CH3-infected ducklings. Thus, our results demonstrated that TbdR1 was involved in hemin iron acquisition and necessary for optimal bacterial virulence.
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Affiliation(s)
- Fengying Lu
- Shanghai Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, 518 Ziyue Road, Shanghai 200241, China
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42
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González-López MA, Velázquez-Guadarrama N, Romero-Espejel ME, Olivares-Trejo JDJ. Helicobacter pylori secretes the chaperonin GroEL (HSP60), which binds iron. FEBS Lett 2013; 587:1823-8. [PMID: 23684642 DOI: 10.1016/j.febslet.2013.04.048] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 04/06/2013] [Accepted: 04/26/2013] [Indexed: 12/16/2022]
Abstract
Helicobacter pylori is a bacterium that can use multiple iron sources. However, it is unknown whether this bacterium secretes molecules such as siderophores or haemophores to scavenge iron. Here, we report the first secreted iron-binding protein of H. pylori, which we purified by haem-affinity chromatography. Mass spectrometry analysis revealed its identity as chaperonin (HpGroEL). When we compared HpGroEL with EcGroEL from Escherichia coli, they were homologous, showing 60% similarity. Additionally, purified cytoplasmic HpGroEL could also bind iron. Perhaps H. pylori secretes HpGroEL to maintain the appropriate folding of extracellular proteins and to bind iron.
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Affiliation(s)
- Marco Antonio González-López
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, San Lorenzo 290, Col Del Valle, México DF, Mexico
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Romero-Espejel ME, González-López MA, de Jesús Olivares-Trejo J. Streptococcus pneumoniae requires iron for its viability and expresses two membrane proteins that bind haemoglobin and haem. Metallomics 2013; 5:384-9. [DOI: 10.1039/c3mt20244e] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Priyadarshini R, Cugini C, Arndt A, Chen T, Tjokro NO, Goodman SD, Davey ME. The nucleoid-associated protein HUβ affects global gene expression in Porphyromonas gingivalis. MICROBIOLOGY-SGM 2012; 159:219-229. [PMID: 23175503 DOI: 10.1099/mic.0.061002-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
HU is a non-sequence-specific DNA-binding protein and one of the most abundant nucleoid-associated proteins in the bacterial cell. Like Escherichia coli, the genome of Porphyromonas gingivalis is predicted to encode both the HUα (PG1258) and the HUβ (PG0121) subunit. We have previously reported that PG0121 encodes a non-specific DNA-binding protein and that PG0121 is co-transcribed with the K-antigen capsule synthesis operon. We also reported that deletion of PG0121 resulted in downregulation of capsule operon expression and produced a P. gingivalis strain that is phenotypically deficient in surface polysaccharide production. Here, we show through complementation experiments in an E. coli MG1655 hupAB double mutant strain that PG0121 encodes a functional HU homologue. Microarray and quantitative RT-PCR analysis were used to further investigate global transcriptional regulation by HUβ using comparative expression profiling of the PG0121 (HUβ) mutant strain to the parent strain, W83. Our analysis determined that expression of genes encoding proteins involved in a variety of biological functions, including iron acquisition, cell division and translation, as well as a number of predicted nucleoid associated proteins were altered in the PG0121 mutant. Phenotypic and quantitative real-time-PCR (qRT-PCR) analyses determined that under iron-limiting growth conditions, cell division and viability were defective in the PG0121 mutant. Collectively, our studies show that PG0121 does indeed encode a functional HU homologue, and HUβ has global regulatory functions in P. gingivalis; it affects not only production of capsular polysaccharides but also expression of genes involved in basic functions, such as cell wall synthesis, cell division and iron uptake.
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Affiliation(s)
- Richa Priyadarshini
- Department of Oral Medicine Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
- Department of Molecular Genetics, The Forsyth Institute, Cambridge, MA, USA
| | - Carla Cugini
- Department of Oral Medicine Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
- Department of Molecular Genetics, The Forsyth Institute, Cambridge, MA, USA
| | - Annette Arndt
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Tsute Chen
- Department of Oral Medicine Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
- Department of Molecular Genetics, The Forsyth Institute, Cambridge, MA, USA
| | - Natalia O Tjokro
- Division of Biomedical Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - Steven D Goodman
- Division of Biomedical Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - Mary E Davey
- Department of Oral Medicine Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
- Department of Molecular Genetics, The Forsyth Institute, Cambridge, MA, USA
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Gao JL, Lu Y, Browne G, Yap BCM, Trewhella J, Hunter N, Nguyen KA. The role of heme binding by DNA-protective protein from starved cells (Dps) in the Tolerance of Porphyromonas gingivalis to heme toxicity. J Biol Chem 2012; 287:42243-58. [PMID: 23086936 DOI: 10.1074/jbc.m112.392787] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The widely expressed DNA-protective protein from starved-cells (Dps) family proteins are considered major contributors to prokaryotic resistance to stress. We show here that Porphyromonas gingivalis Dps (PgDps), previously described as an iron-storage and DNA-binding protein, also mediates heme sequestration. We determined that heme binds strongly to PgDps with an apparent K(d) of 3.7 × 10(-8) m and is coordinated by a single surface-located cysteine at the fifth axial ligand position. Heme and iron sequestered in separate sites by PgDps provide protection of DNA from H(2)O(2)-mediated free radical damage and were found to be important for growth of P. gingivalis under excess heme as the only iron source. Conservation of the heme-coordinating cysteine among Dps isoforms from the Bacteroidales order suggests that this function may be a common feature within these anaerobic bacteria.
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Affiliation(s)
- Jin-Long Gao
- University of Sydney, New South Wales 2006, Australia
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46
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Carrizo-Chávez MA, Cruz-Castañeda A, Olivares-Trejo JDJ. The frpB1 gene of Helicobacter pylori is regulated by iron and encodes a membrane protein capable of binding haem and haemoglobin. FEBS Lett 2012; 586:875-9. [PMID: 22449974 DOI: 10.1016/j.febslet.2012.02.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 02/07/2012] [Accepted: 02/10/2012] [Indexed: 11/15/2022]
Abstract
FrpB1 is a novel membrane protein of Helicobacter pylori that is capable of binding both haem and haemoglobin but consistently shows more affinity for haem. The mRNA levels of frpB1 were repressed by iron and lightly modulated by haem or haemoglobin. The overexpression of the frpB1 gene supported cellular growth when haem or haemoglobin were supplied as the only iron source. Three-dimensional modelling revealed the presence of motifs necessary to bind either haem or haemoglobin. Our overall results support the idea that FrpB1 is a membrane protein of H. pylori that allows this pathogen to survive in the human stomach.
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Affiliation(s)
- Miguel Angel Carrizo-Chávez
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, San Lorenzo 290, Del Valle, México DF, Mexico
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Smith AD, Wilks A. Extracellular heme uptake and the challenges of bacterial cell membranes. CURRENT TOPICS IN MEMBRANES 2012; 69:359-92. [PMID: 23046657 PMCID: PMC3731948 DOI: 10.1016/b978-0-12-394390-3.00013-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In bacteria, the fine balance of maintaining adequate iron levels while preventing the deleterious effects of excess iron has led to the evolution of sophisticated cellular mechanisms to obtain, store, and regulate iron. Iron uptake provides a significant challenge given its limited bioavailability and need to be transported across the bacterial cell wall and membranes. Pathogenic bacteria have circumvented the iron-availability issue by utilizing the hosts' heme-containing proteins as a source of iron. Once internalized, iron is liberated from the porphyrin enzymatically for cellular processes within the bacterial cell. Heme, a lipophilic and toxic molecule, poses a significant challenge in terms of transport given its chemical reactivity. As such, pathogenic bacteria have evolved sophisticated membrane transporters to coordinate, sequester, and transport heme. Recent advances in the biochemical and structural characterization of the membrane-bound heme transport proteins are discussed in the context of ligand coordination, protein-protein interaction, and heme transfer.
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Affiliation(s)
- Aaron D. Smith
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, USA
| | - Angela Wilks
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, USA
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Krishna Kumar K, Jacques DA, Pishchany G, Caradoc-Davies T, Spirig T, Malmirchegini GR, Langley DB, Dickson CF, Mackay JP, Clubb RT, Skaar EP, Guss JM, Gell DA. Structural basis for hemoglobin capture by Staphylococcus aureus cell-surface protein, IsdH. J Biol Chem 2011; 286:38439-38447. [PMID: 21917915 PMCID: PMC3207429 DOI: 10.1074/jbc.m111.287300] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 08/16/2011] [Indexed: 02/02/2023] Open
Abstract
Pathogens must steal iron from their hosts to establish infection. In mammals, hemoglobin (Hb) represents the largest reservoir of iron, and pathogens express Hb-binding proteins to access this source. Here, we show how one of the commonest and most significant human pathogens, Staphylococcus aureus, captures Hb as the first step of an iron-scavenging pathway. The x-ray crystal structure of Hb bound to a domain from the Isd (iron-regulated surface determinant) protein, IsdH, is the first structure of a Hb capture complex to be determined. Surface mutations in Hb that reduce binding to the Hb-receptor limit the capacity of S. aureus to utilize Hb as an iron source, suggesting that Hb sequence is a factor in host susceptibility to infection. The demonstration that pathogens make highly specific recognition complexes with Hb raises the possibility of developing inhibitors of Hb binding as antibacterial agents.
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Affiliation(s)
- Kaavya Krishna Kumar
- School of Molecular Bioscience, University of Sydney, New South Wales 2006, Australia
| | - David A Jacques
- School of Molecular Bioscience, University of Sydney, New South Wales 2006, Australia
| | - Gleb Pishchany
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical School, Nashville, Tennessee 37232
| | | | - Thomas Spirig
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095
| | | | - David B Langley
- School of Molecular Bioscience, University of Sydney, New South Wales 2006, Australia
| | - Claire F Dickson
- Menzies Research Institute, University of Tasmania, Tasmania 7000, Australia
| | - Joel P Mackay
- School of Molecular Bioscience, University of Sydney, New South Wales 2006, Australia
| | - Robert T Clubb
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095
| | - Eric P Skaar
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical School, Nashville, Tennessee 37232
| | - J Mitchell Guss
- School of Molecular Bioscience, University of Sydney, New South Wales 2006, Australia
| | - David A Gell
- Menzies Research Institute, University of Tasmania, Tasmania 7000, Australia.
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Yukitake H, Naito M, Sato K, Shoji M, Ohara N, Yoshimura M, Sakai E, Nakayama K. Effects of non-iron metalloporphyrins on growth and gene expression of Porphyromonas gingivalis. Microbiol Immunol 2011; 55:141-53. [PMID: 21204951 DOI: 10.1111/j.1348-0421.2010.00299.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The oral anaerobic bacterium Porphyromonas gingivalis, which is implicated as an important pathogen for chronic periodontitis, requires heme for its growth. Non-iron metalloporphyrins, In-PPIX and Ga-PPIX, were examined for antibacterial effects on P. gingivalis. Both In-PPIX and Ga-PPIX caused retardation of P. gingivalis growth in a dose-dependent fashion. Microarray and qPCR analyses revealed that In-PPIX treatment upregulated the expression of several genes encoding proteins including ClpB and ClpC, which are members of the Clp (caseinolytic protease, Hsp100) family, and aRNR, aRNR-activating protein and thioredoxin reductase, whereas In-PPIX treatment had no effect on the expression of genes encoding proteins involved in heme uptake pathways, Hmu-mediated, Iht-mediated and Tlr-mediated pathways. P. gingivalis ihtA and ihtB mutants were more resistant to In-PPIX than was the wild-type parent, whereas hmuR and tlr mutants did not show such resistance to In-PPIX. The results suggest that In-PPIX is incorporated by the Iht-mediated heme uptake pathway and that it influences protein quality control and nucleotide metabolism and retards growth of P. gingivalis.
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Affiliation(s)
- Hideharu Yukitake
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Sakamoto, Nagasaki, Japan
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González-López MA, Olivares-Trejo JJ. The gene frpB2 of Helicobacter pylori encodes an hemoglobin-binding protein involved in iron acquisition. Biometals 2011; 22:889-94. [PMID: 19357969 DOI: 10.1007/s10534-009-9240-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Accepted: 03/26/2009] [Indexed: 11/27/2022]
Abstract
Human hemoglobin (Hb) is a metalloprotein used by pathogens as a source of iron during invasive process. It can support the Helicobacter pylori growth and several proteins are induced during iron starvation. However, the identity of those proteins remains unknown. In this work, by in silico analysis we identified FrpB2 in H. pylori genome. This protein was annotated as an iron-regulated outer membrane protein. Multiple amino acid alignment showed the motifs necessary for Hb-binding. We demonstrate the ability of FrpB2 to bind Hb by overlay experiments. In addition, the overexpression of this gene allowed the cell growth in media without free iron but supplemented with Hb. All these results support the idea that frpB2 is a gene of H. pylori involved in iron acquisition when Hb is used as a sole iron source.
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Affiliation(s)
- Marco A González-López
- Posgrado en Ciencias Genómicas, Universidad Autónoma de Ciudad de México, San Lorenzo 290, 03100 México, DF, México
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