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Vahvelainen N, Bozkurt E, Maula T, Johansson A, Pöllänen MT, Ihalin R. Pilus PilA of the naturally competent HACEK group pathogen Aggregatibacter actinomycetemcomitans stimulates human leukocytes and interacts with both DNA and proinflammatory cytokines. Microb Pathog 2022; 173:105843. [DOI: 10.1016/j.micpath.2022.105843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 10/20/2022] [Accepted: 10/20/2022] [Indexed: 11/11/2022]
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2
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da Silva MP, Silva VDO, Pasetto S, Ando-Suguimoto ES, Kawamoto D, Mata GMSC, Murata RM, Mayer MPA, Chen C. Aggregatibacter actinomycetemcomitans Outer Membrane Proteins 29 and 29 Paralogue Induce Evasion of Immune Response. FRONTIERS IN ORAL HEALTH 2022; 3:835902. [PMID: 35187533 PMCID: PMC8851312 DOI: 10.3389/froh.2022.835902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 01/03/2022] [Indexed: 11/22/2022] Open
Abstract
Aggregatibacter actinomycetemcomitans (Aa) is abundant within the microbial dysbiotic community of some patients with periodontitis. Aa outer membrane protein 29 (OMP29), a member of the OMPA family, mediates the invasion of Aa to gingival epithelial cells (GECs). This study evaluated the effect of OMP29 and its paralogue OMP29par on the response of GECs to Aa. The omp29 or/and omp29par deletion mutants AaΔ29, AaΔ29P, and AaΔ29Δ29P were constructed, and recombinant Aa OMP29His was obtained. Microarray analysis and the evaluation of cxcl-8 gene expression were performed to examine the response of GECs line OBA-09 to Aa and its mutants. The expression of cxcl-8 and its product CXCL-8 was examined in LPS-stimulated OBA-09 cells with Aa OMP29His. Proteomics analysis showed that the deletion of omp29 led to overexpression of both OMP29par and another membrane protein OMP39, the expression of which was further increased in AaΔ29Δ29P. OBA-09 cells challenged with AaΔ29Δ29P exhibited a higher expression of cxcl-8 in comparison to wildtype Aa strain AaD7S or single-deletion mutants AaΔ29 or AaΔ29P. LPS-stimulated OBA-09 cells challenged with Aa OMP29His showed reduced expressions of cxcl-8 and its product CXCL-8. OBA-09 cells challenged with AaΔ29Δ29P in comparison to Aa strain AaD7S resulted in higher expressions of genes involved in apoptosis and inflammatory response such as bcl2, birc3, casp3, c3, ep300, fas, fosb, grb2, il-1α, il-1β, il-6, cxcl-8, nr3c1, prkcq, socs3, and tnfrsf1β and reduced expressions of cd74, crp, faslg, tlr1, and vcam1. The results suggested a novel strategy of Aa, mediated by OMP29 and OMP29par, to evade host immune response by inhibiting CXCL-8 expression and modulating the genes involved in apoptosis and inflammatory response in GECs. Pending further confirmation, the strategy might interfere with the recruitment of neutrophils and dampen the host inflammatory response, leading to a more permissive subgingival niche for bacterial growth.
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Affiliation(s)
- Maike Paulino da Silva
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
- Division of Periodontology, Diagnostic Sciences and Dental Hygiene, Ostrow School of Dentistry of University of Southern California, Los Angeles, CA, United States
| | - Viviam de Oliveira Silva
- Division of Periodontology, Diagnostic Sciences and Dental Hygiene, Ostrow School of Dentistry of University of Southern California, Los Angeles, CA, United States
- Centro Universitário Atenas- UniAtenas, Paracatu, Brazil
| | - Silvana Pasetto
- Division of Periodontology, Diagnostic Sciences and Dental Hygiene, Ostrow School of Dentistry of University of Southern California, Los Angeles, CA, United States
- Department of Comprehensive Oral Health, Adams School of Dentistry, University of North Carolina, Chapel Hill, NC, United States
| | - Ellen Sayuri Ando-Suguimoto
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Dione Kawamoto
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Gardênia Márcia Silva Campos Mata
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
- Instituto de Alimentação e Nutrição, Centro Multidisciplinar UFRJ-Macaé, Universidade Federal do Rio de Janeiro, Macaé, Brazil
| | - Ramiro Mendonça Murata
- Department of Foundational Sciences, School of Dental Medicine of University of East Carolina University, Greenville, NC, United States
| | - Marcia Pinto Alves Mayer
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Casey Chen
- Division of Periodontology, Diagnostic Sciences and Dental Hygiene, Ostrow School of Dentistry of University of Southern California, Los Angeles, CA, United States
- *Correspondence: Casey Chen
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Maula T, Vahvelainen N, Tossavainen H, Koivunen T, T. Pöllänen M, Johansson A, Permi P, Ihalin R. Decreased temperature increases the expression of a disordered bacterial late embryogenesis abundant (LEA) protein that enhances natural transformation. Virulence 2021; 12:1239-1257. [PMID: 33939577 PMCID: PMC8096337 DOI: 10.1080/21505594.2021.1918497] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/22/2021] [Accepted: 04/03/2021] [Indexed: 11/02/2022] Open
Abstract
Late embryogenesis abundant (LEA) proteins are important players in the management of responses to stressful conditions, such as drought, high salinity, and changes in temperature. Many LEA proteins do not have defined three-dimensional structures, so they are intrinsically disordered proteins (IDPs) and are often highly hydrophilic. Although LEA-like sequences have been identified in bacterial genomes, the functions of bacterial LEA proteins have been studied only recently. Sequence analysis of outer membrane interleukin receptor I (BilRI) from the oral pathogen Aggregatibacter actinomycetemcomitans indicated that it shared sequence similarity with group 3/3b/4 LEA proteins. Comprehensive nuclearcgq magnetic resonance (NMR) studies confirmed its IDP nature, and expression studies in A. actinomycetemcomitans harboring a red fluorescence reporter protein-encoding gene revealed that bilRI promoter expression was increased at decreased temperatures. The amino acid backbone of BilRI did not stimulate either the production of reactive oxygen species from human leukocytes or the production of interleukin-6 from human macrophages. Moreover, BilRI-specific IgG antibodies could not be detected in the sera of A. actinomycetemcomitans culture-positive periodontitis patients. Since the bilRI gene is located near genes involved in natural competence (i.e., genes associated with the uptake of extracellular (eDNA) and its incorporation into the genome), we also investigated the role of BilRI in these events. Compared to wild-type cells, the ΔbilRI mutants showed a lower transformation efficiency, which indicates either a direct or indirect role in natural competence. In conclusion, A. actinomycetemcomitans might express BilRI, especially outside the host, to survive under stressful conditions and improve its transmission potential.
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Affiliation(s)
- Terhi Maula
- Department of Life Technologies, University of Turku, Turku, Finland
| | - Nelli Vahvelainen
- Department of Life Technologies, University of Turku, Turku, Finland
| | - Helena Tossavainen
- Department of Biological and Environmental Sciences, Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland
| | - Tuuli Koivunen
- Department of Life Technologies, University of Turku, Turku, Finland
| | | | - Anders Johansson
- Division of Molecular Periodontology, Department of Odontology, Umeå University, Umeå, Sweden
| | - Perttu Permi
- Department of Biological and Environmental Sciences, Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland
- Department of Chemistry, Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland
| | - Riikka Ihalin
- Department of Life Technologies, University of Turku, Turku, Finland
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Rebeis ES, Albuquerque-Souza E, Paulino da Silva M, Giudicissi M, Mayer MPA, Saraiva L. Effect of periodontal treatment onAggregatibacter actinomycetemcomitanscolonization and serum IgG levels againstA. actinomycetemcomitansserotypes and Omp29 of aggressive periodontitis patients. Oral Dis 2018; 25:569-579. [DOI: 10.1111/odi.13010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 11/04/2018] [Accepted: 11/22/2018] [Indexed: 01/07/2023]
Affiliation(s)
- Estela Sanches Rebeis
- Division of Periodontics, Department of Stomatology, School of Dentistry; University of Sao Paulo; Sao Paulo Brazil
| | - Emmanuel Albuquerque-Souza
- Division of Periodontics, Department of Stomatology, School of Dentistry; University of Sao Paulo; Sao Paulo Brazil
| | - Maike Paulino da Silva
- Department of Microbiology, Institute of Biomedical Sciences; University of São Paulo; Sao Paulo Brazil
| | - Marcela Giudicissi
- Division of Periodontics, Department of Stomatology, School of Dentistry; University of Sao Paulo; Sao Paulo Brazil
| | - Marcia P. A. Mayer
- Division of Periodontics, Department of Stomatology, School of Dentistry; University of Sao Paulo; Sao Paulo Brazil
- Department of Microbiology, Institute of Biomedical Sciences; University of São Paulo; Sao Paulo Brazil
| | - Luciana Saraiva
- Division of Periodontics, Department of Stomatology, School of Dentistry; University of Sao Paulo; Sao Paulo Brazil
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Ahlstrand T, Kovesjoki L, Maula T, Oscarsson J, Ihalin R. Aggregatibacter actinomycetemcomitans LPS binds human interleukin-8. J Oral Microbiol 2018; 11:1549931. [PMID: 34917288 PMCID: PMC8670607 DOI: 10.1080/20002297.2018.1549931] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Various gram-negative species sequester host cytokines using outer membrane proteins or surface modulation by sulfated polysaccharides. An outer membrane lipoprotein (BilRI) of the periodontal pathogen Aggregatibacter actinomycetemcomitans binds several cytokines, including interleukin (IL)-8. Because IL-8 is positively charged at physiological pH, we aimed to determine whether IL-8 interacts with negatively charged lipopolysaccharide (LPS). Binding was investigated using electrophoretic mobility shift assays and microwell-based time-resolved fluorometric immunoassay. LPS from each tested strain of A. actinomycetemcomitans (N = 13), Pseudomonas aeruginosa (N = 1) and Escherichia coli (N = 1) bound IL-8. The Kd value of the A. actinomycetemcomitans LPS-IL-8 interaction varied between 1.2–17 μM irrespective of the serotype and the amount of phosphorus in LPS and was significantly lower than that of the BilRI-IL-8 interaction. Moreover, IL-8 interacted with whole A. actinomycetemcomitans cells and outer membrane vesicles. Hence, LPS might be involved in binding of IL-8 to the outer membrane of A. actinomycetemcomitans. This raises an interesting question regarding whether other gram-negative periodontal pathogens use LPS for IL-8 sequestering in vivo.
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Affiliation(s)
- Tuuli Ahlstrand
- Department of Biochemistry, University of Turku, Turku, Finland
| | - Laura Kovesjoki
- Department of Biochemistry, University of Turku, Turku, Finland
| | - Terhi Maula
- Department of Biochemistry, University of Turku, Turku, Finland
| | - Jan Oscarsson
- Oral Microbiology, Department of Odontology, Umeå University, Umeå, Sweden
| | - Riikka Ihalin
- Department of Biochemistry, University of Turku, Turku, Finland
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6
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Silva VDO, Pereira LJ, Pasetto S, da Silva MP, Meyers JC, Murata RM. Effects of Monolaurin on Oral Microbe-Host Transcriptome and Metabolome. Front Microbiol 2018; 9:2638. [PMID: 30467497 PMCID: PMC6237204 DOI: 10.3389/fmicb.2018.02638] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 10/16/2018] [Indexed: 11/13/2022] Open
Abstract
The aim of this in vitro study was to evaluate the effects of monolaurin against Aggregatibacter actinomycetemcomitans (Aa) and determine their effects on the host transcriptome and metabolome, using an oral cell/bacteria co-culture dual-chamber model to mimic the human periodontium. For this, the Aa, was applied to cross the monolayer of epithelial keratinocytes (OBA-9) to reach the fibroblasts layer (HGF-1) in the basal chamber. The Monolaurin treatments (25 or 50 μM) were added immediately after the inoculation of the dual-chamber with Aa. After 24 h, the transcriptional factors and metabolites produced were quantified in the remaining cell layers (insert and basal chamber) and in supernatant released from the cells. The genes IL-1α, IL-6, IL-18, and TNF analyzed in HGF-1 concentrations showed a decreased expression when treated with both concentration of Monolaurin. In keratinocytes, the genes IL-6, IL-18, and TNF presented a higher expression and the expression of IL-1α decreased when treated with the two cited concentrations. The production of glycerol and pyruvic acid increased, and the 2-deoxytetronic acid NIST, 4-aminobutyric acid, pinitol and glyceric acid, presented lower concentrations because of the treatment with 25 and/or 50 μM of Monolaurin. Use of monolaurin modulated the immune response and metabolite production when administered for 24 h in a dual-chamber model inoculated with A. actinomycetemcomitans. In summary, this study indicates that monolaurin had antimicrobial activity and modulated the host immune response and metabolite production when administered for 24 h in a dual-chamber model inoculated with A. actinomycetemcomitans.
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Affiliation(s)
- Viviam de Oliveira Silva
- Department of Veterinary Medicine, Federal University of Lavras, Lavras, Brazil.,Division of Periodontology, Diagnostic Sciences, Dental Hygiene and Biomedical Science, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, United States
| | | | - Silvana Pasetto
- Division of Periodontology, Diagnostic Sciences, Dental Hygiene and Biomedical Science, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, United States
| | - Maike Paulino da Silva
- Division of Periodontology, Diagnostic Sciences, Dental Hygiene and Biomedical Science, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, United States
| | - Jered Cope Meyers
- Department Foundational Sciences, School of Dental Medicine, East Carolina University, Greenville, NC, United States
| | - Ramiro Mendonça Murata
- Department Foundational Sciences, School of Dental Medicine, East Carolina University, Greenville, NC, United States.,Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
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7
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Mahabady S, Tjokro N, Aharonian S, Zadeh HH, Chen C, Allayee H, Sedghizadeh PP. The in vivo T helper type 17 and regulatory T cell immune responses to Aggregatibacter actinomycetemcomitans. Mol Oral Microbiol 2017; 32:490-499. [PMID: 28544588 DOI: 10.1111/omi.12187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2017] [Indexed: 12/01/2022]
Abstract
The periodontal pathogen Aggregatibacter actinomycetemcomitans is known to elicit a systemic immune response in the infected host, and occasionally causes non-oral infections. Detailed information on its immunopathological responses and the involvement of bacterial virulence factors remains to be elucidated. The aim of this study was to assess the systemic immune response to A. actinomycetemcomitans oral infection. We used an animal model that simulates systemic dissemination of the bacteria by injecting live wild-type (WT) D7S-1 and a double knockout mutant of leukotoxin and cytolethal distending toxin (ΔltxΔcdt) A. actinomycetemcomitans strains in rat oral mucosa. Draining lymph nodes were examined for regulatory T (Treg) and T helper type 17 (Th17) cell subsets and their associated mediators. An increase in the proportion of Th17 cells and a decrease in Treg cells over the experimental period of 3 weeks were similarly observed for rats challenged with WT and ΔltxΔcdt. Significant upregulation and downregulation of proinflammatory cytokines in the Th17 gene pathway was noted, as well as several qualitative differences between WT and ΔltxΔcdt. Furthermore, we observed differential fold regulation in key genes associated with a proinflammatory response in ΔltxΔcdt-inoculated rats relative to D7S-1 group. This suggests that although the knockout of these two virulence factors (ΔltxΔcdt) may suppress certain proinflammatory genes, it causes similar over-expression of other genes compared with D7S-1, indicating a common factor that still remains in the pathogenicity of A. actinomycetemcomitans.
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Affiliation(s)
- S Mahabady
- Laboratory for Immunoregulation & Tissue Engineering, Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - N Tjokro
- Division of Periodontology, Diagnostic Sciences and Biomedical Sciences, Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - S Aharonian
- Laboratory for Immunoregulation & Tissue Engineering, Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - H H Zadeh
- Laboratory for Immunoregulation & Tissue Engineering, Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - C Chen
- Division of Periodontology, Diagnostic Sciences and Biomedical Sciences, Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - H Allayee
- Institute for Genetic Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - P P Sedghizadeh
- Division of Periodontology, Diagnostic Sciences and Biomedical Sciences, Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
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8
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Silva VDO, Pereira LJ, Murata RM. Oral microbe-host interactions: influence of β-glucans on gene expression of inflammatory cytokines and metabolome profile. BMC Microbiol 2017; 17:53. [PMID: 28270109 PMCID: PMC5341410 DOI: 10.1186/s12866-017-0946-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Accepted: 02/04/2017] [Indexed: 12/31/2022] Open
Abstract
Background The aim of this study was to evaluate the effects of β-glucan on the expression of inflammatory mediators and metabolomic profile of oral cells [keratinocytes (OBA-9) and fibroblasts (HGF-1) in a dual-chamber model] infected by Aggregatibacter actinomycetemcomitans. The periodontopathogen was applied and allowed to cross the top layer of cells (OBA-9) to reach the bottom layer of cells (HGF-1) and induce the synthesis of immune factors and cytokines in the host cells. β-glucan (10 μg/mL or 20 μg/mL) were added, and the transcriptional factors and metabolites produced were quantified in the remaining cell layers and supernatant. Results The relative expression of interleukin (IL)-1-α and IL-18 genes in HGF-1 decreased with 10 μg/mL or 20 μg/mL of β-glucan, where as the expression of PTGS-2 decreased only with 10 μg/mL. The expression of IL-1-α increased with 20 μg/mL and that of IL-18 increased with 10 μg/mL in OBA-9; the expression of BCL 2, EP 300, and PTGS-2 decreased with the higher dose of β-glucan. The production of the metabolite 4-aminobutyric acid presented lower concentrations under 20 μg/mL, whereas the concentrations of 2-deoxytetronic acid NIST and oxalic acid decreased at both concentrations used. Acetophenone, benzoic acid, and pinitol presented reduced concentrations only when treated with 10 μg/mL of β-glucan. Conclusions Treatment with β-glucans positively modulated the immune response and production of metabolites.
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Affiliation(s)
- Viviam de Oliveira Silva
- Herman Ostrow School of Dentistry, Division of Periodontology Diagnostic Sciences, Dental Hygiene & Biomedical Science, University of Southern California, Los Angeles, CA, USA.,Department of Veterinary Medicine, Physiology and Pharmacology Area, Federal University of Lavras, Lavras, Minas Gerais, Brazil
| | - Luciano José Pereira
- Department of Health Sciences, Physiology Area, Federal University of Lavras,Lavras, Minas Gerais, Brazil
| | - Ramiro Mendonça Murata
- School of Dental Medicine, Department Foundational Sciences, East Carolina University, 1851 MacGregor Downs Road, Greeville, NC, 27834-4354, USA. .,Brody School of Medicine, Department of Microbiology and Immunology, East Carolina University, Greenville, NC, USA.
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9
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Tang-Siegel G, Bumgarner R, Ruiz T, Kittichotirat W, Chen W, Chen C. Human Serum-Specific Activation of Alternative Sigma Factors, the Stress Responders in Aggregatibacter actinomycetemcomitans. PLoS One 2016; 11:e0160018. [PMID: 27490177 PMCID: PMC4973924 DOI: 10.1371/journal.pone.0160018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 07/12/2016] [Indexed: 01/08/2023] Open
Abstract
Aggregatibacter actinomycetemcomitans, a known pathogen causing periodontal disease and infective endocarditis, is a survivor in the periodontal pocket and blood stream; both environments contain serum as a nutrient source. To screen for unknown virulence factors associated with this microorganism, A. actinomycetemcomitans was grown in serum-based media to simulate its in vivo environment. Different strains of A. actinomycetemcomitans showed distinct growth phenotypes only in the presence of human serum, and they were grouped into high- and low-responder groups. High-responders comprised mainly serotype c strains, and showed an unusual growth phenomenon, featuring a second, rapid increase in turbidity after 9-h incubation that reached a final optical density 2- to 7-fold higher than low-responders. Upon further investigation, the second increase in turbidity was not caused by cell multiplication, but by cell death. Whole transcriptomic analysis via RNA-seq identified 35 genes that were up-regulated by human serum, but not horse serum, in high-responders but not in low-responders, including prominently an alternative sigma factor rpoE (σE). A lacZ reporter construct driven by the 132-bp rpoE promoter sequence of A. actinomycetemcomitans responded dramatically to human serum within 90 min of incubation only when the construct was carried by a high responder strain. The rpoE promoter is 100% identical among high- and low-responder strains. Proteomic investigation showed potential interactions between human serum protein, e.g. apolipoprotein A1 (ApoA1) and A. actinomycetemcomitans. The data clearly indicated a different activation process for rpoE in high- versus low-responder strains. This differential human serum-specific activation of rpoE, a putative extra-cytoplasmic stress responder and global regulator, suggests distinct in vivo adaptations among different strains of A. actinomycetemcomitans.
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Affiliation(s)
- Gaoyan Tang-Siegel
- Department of Molecular Physiology and Biophysics, College of Medicine, University of Vermont, Burlington, VT, United States of America
| | - Roger Bumgarner
- Department of Microbiology, University of Washington, Seattle, WA, United States of America
| | - Teresa Ruiz
- Department of Molecular Physiology and Biophysics, College of Medicine, University of Vermont, Burlington, VT, United States of America
| | - Weerayuth Kittichotirat
- Systems Biology and Bioinformatics Research Group, Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
| | - Weizhen Chen
- Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, United States of America
| | - Casey Chen
- Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, United States of America
- * E-mail:
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10
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Freire MO, Devaraj A, Young A, Navarro JB, Downey JS, Chen C, Bakaletz LO, Zadeh HH, Goodman SD. A bacterial-biofilm-induced oral osteolytic infection can be successfully treated by immuno-targeting an extracellular nucleoid-associated protein. Mol Oral Microbiol 2016; 32:74-88. [PMID: 26931773 DOI: 10.1111/omi.12155] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/28/2016] [Indexed: 02/06/2023]
Abstract
Periodontal disease exemplifies a chronic and recurrent infection with a necessary biofilm component. Mucosal inflammation is a hallmark response of the host seen in chronic diseases, such as colitis, gingivitis, and periodontitis (and the related disorder peri-implantitis). We have taken advantage of our recently developed rat model of human peri-implantitis that recapitulates osteolysis, the requirement of biofilm formation, and the perpetuation of the bona fide disease state, to test a new therapeutic modality with two novel components. First we used hyperimmune antiserum directed against the DNABII family of proteins, now known to be a critical component of the extracellular matrix of bacterial biofilms. Second we delivered the antiserum as cargo in biodegradable microspheres to the site of the biofilm infection. We demonstrated that delivery of a single dose of anti-DNABII in poly(lactic-co-glycolic acid) (PLGA) microspheres induced significant resolution of experimental peri-implantitis, including marked reduction of inflammation. These data support the continued development of a DNABII protein-targeted therapeutic for peri-implantitis and other chronic inflammatory pathologies of the oral cavity in animals and humans.
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Affiliation(s)
- M O Freire
- Department of Applied Oral Sciences, The Forsyth Institute, Cambridge, MA, USA.,Department of Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
| | - A Devaraj
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, and The Ohio State University College of Medicine, Columbus, OH, USA
| | - A Young
- Division of Periodontology, Diagnostic Sciences & Dental Hygiene Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - J B Navarro
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, and The Ohio State University College of Medicine, Columbus, OH, USA
| | - J S Downey
- Division of Periodontology, Diagnostic Sciences & Dental Hygiene Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - C Chen
- Division of Periodontology, Diagnostic Sciences & Dental Hygiene Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - L O Bakaletz
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, and The Ohio State University College of Medicine, Columbus, OH, USA
| | - H H Zadeh
- Division of Periodontology, Diagnostic Sciences & Dental Hygiene Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA.,Laboratory for Immunoregulation and Tissue Engineering (LITE), University of Southern California, Los Angeles, CA, USA
| | - S D Goodman
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, and The Ohio State University College of Medicine, Columbus, OH, USA
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11
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Doğan B, Chen J, Çiftlikli SY, Huang J, Kadir T, Alnıak AK, Chen C. Occurrence and serotype distribution of Aggregatibacter actinomycetemcomitans in subjects without periodontitis in Turkey. Arch Oral Biol 2015; 61:125-9. [PMID: 26556547 DOI: 10.1016/j.archoralbio.2015.10.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 09/25/2015] [Accepted: 10/25/2015] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To determine the occurrence and serotype distribution of Aggregatibacter actinomycetemcomitans in subjects without periodontitis. DESIGN Systemically healthy dental students without periodontitis (n=94), who had not used antibiotics within the last 3 months or received any form of periodontal therapy within the last 6 months, were included in the study. Pooled subgingival microbiological samples were collected from 4 first molars and 4 central incisors in each subject using sterile paper points. All samples were tested for the presence and the serotype of A. actinomycetemcomitans through PCR analysis of the 16S rRNA genes and the serotype-specific gene clusters in the DNA extracted from the samples. RESULTS Of the 94 samples that were tested, 43 (46%) were positive for A. actinomycetemcomitans. No statistically significant differences in clinical parameters were found between subgingival sites with or without detectable A. actinomycetemcomitans (t-test, P>0.01). Among the 43 A. actinomycetemcomitans-positive samples, the serotype was identified in 21 samples. Fifteen were positive for A. actinomycetemcomitans serotype a, 1 for serotype b, 1 for serotype c, and 4 for serotype f, while serotypes d and e were not detected. CONCLUSION A. actinomycetemcomitans serotype a is the most commonly found serotype among Turkish dental students without periodontitis.
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Affiliation(s)
- Başak Doğan
- Department of Periodontology, Faculty of Dentistry, Marmara University, Istanbul, Turkey
| | - Jason Chen
- Division of Periodontology, Diagnostic Sciences and Dental Hygiene, Ostrow School of Dentistry, University of Southern California, USA
| | - Sinem Yıldız Çiftlikli
- Department of Periodontology, Faculty of Dentistry, Marmara University, Istanbul, Turkey
| | - Jonathan Huang
- Division of Periodontology, Diagnostic Sciences and Dental Hygiene, Ostrow School of Dentistry, University of Southern California, USA
| | - Tanju Kadir
- Department of Microbiology, Faculty of Dentistry, Marmara University, Istanbul, Turkey
| | - Anıl Kınacı Alnıak
- Department of Periodontology, Faculty of Dentistry, Marmara University, Istanbul, Turkey
| | - Casey Chen
- Division of Periodontology, Diagnostic Sciences and Dental Hygiene, Ostrow School of Dentistry, University of Southern California, USA.
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Benso B, Rosalen PL, Alencar SM, Murata RM. Malva sylvestris Inhibits Inflammatory Response in Oral Human Cells. An In Vitro Infection Model. PLoS One 2015; 10:e0140331. [PMID: 26479870 PMCID: PMC4610699 DOI: 10.1371/journal.pone.0140331] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 09/24/2015] [Indexed: 12/24/2022] Open
Abstract
The aim of this study was to investigate the in vitro anti-inflammatory activity of Malva sylvestris extract (MSE) and fractions in a co-culture model of cells infected by Aggregatibacter actinomycetemcomitans. In addition, we evaluated the phytochemical content in the extract and fractions of M. sylvestris and demonstrated that polyphenols were the most frequent group in all samples studied. An in vitro dual-chamber model to mimic the periodontal structure was developed using a monolayer of epithelial keratinocytes (OBA-9) and a subepithelial layer of fibroblasts (HGF-1). The invasive periodontopathogen A. actinomycetemcomitans (D7S-1) was applied to migrate through the cell layers and induce the synthesis of immune factors and cytokines in the host cells. In an attempt to analyze the antimicrobial properties of MSE and fractions, a susceptibility test was carried out. The extract (MIC 175 μg/mL, MBC 500μg/mL) and chloroform fraction (MIC 150 μg/mL, MBC 250 μg/mL) were found to have inhibitory activity. The extract and all fractions were assessed using a cytotoxicity test and results showed that concentrations under 100 μg/mL did not significantly reduce cell viability compared to the control group (p > 0.05, viability > 90%). In order to analyze the inflammatory response, transcriptional factors and cytokines were quantified in the supernatant released from the cells. The chloroform fraction was the most effective in reducing the bacterial colonization (p< 0.05) and controlling inflammatory mediators, and promoted the down-regulation of genes including IL-1beta, IL-6, IL-10, CD14, PTGS, MMP-1 and FOS as well as the reduction of the IL-1beta, IL-6, IL-8 and GM-CSF protein levels (p< 0.05). Malva sylvestris and its chloroform fraction minimized the A. actinomycetemcomitans infection and inflammation processes in oral human cells by a putative pathway that involves important cytokines and receptors. Therefore, this natural product may be considered as a successful dual anti-inflammatory-antimicrobial candidate.
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Affiliation(s)
- Bruna Benso
- Department of Physiological Sciences, Piracicaba Dental School, University of Campinas, Piracicaba, Sao Paulo, Brazil
| | - Pedro Luiz Rosalen
- Department of Physiological Sciences, Piracicaba Dental School, University of Campinas, Piracicaba, Sao Paulo, Brazil
| | - Severino Matias Alencar
- Department of Agri-food Industry, Food and Nutrition, “Luiz de Queiroz” College of Agriculture, University of Sao Paulo, Piracicaba, Sao Paulo, Brazil
| | - Ramiro Mendonça Murata
- Division of Periodontology, Diagnostic Sciences & Dental Hygiene and Division of Biomedical Sciences Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, United States of America
- * E-mail:
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Phylogenomic and molecular demarcation of the core members of the polyphyletic pasteurellaceae genera actinobacillus, haemophilus, and pasteurella. Int J Genomics 2015; 2015:198560. [PMID: 25821780 PMCID: PMC4363679 DOI: 10.1155/2015/198560] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 01/19/2015] [Accepted: 01/26/2015] [Indexed: 12/18/2022] Open
Abstract
The genera Actinobacillus, Haemophilus, and Pasteurella exhibit extensive polyphyletic branching in phylogenetic trees and do not represent coherent clusters of species. In this study, we have utilized molecular signatures identified through comparative genomic analyses in conjunction with genome based and multilocus sequence based phylogenetic analyses to clarify the phylogenetic and taxonomic boundary of these genera. We have identified large clusters of Actinobacillus, Haemophilus, and Pasteurella species which represent the “sensu stricto” members of these genera. We have identified 3, 7, and 6 conserved signature indels (CSIs), which are specifically shared by sensu stricto members of Actinobacillus, Haemophilus, and Pasteurella, respectively. We have also identified two different sets of CSIs that are unique characteristics of the pathogen containing genera Aggregatibacter and Mannheimia, respectively. It is now possible to demarcate the genera Actinobacillus sensu stricto, Haemophilus sensu stricto, and Pasteurella sensu stricto on the basis of discrete molecular signatures. The other members of the genera Actinobacillus, Haemophilus, and Pasteurella that do not fall within the “sensu stricto” clades and do not contain these molecular signatures should be reclassified as other genera. The CSIs identified here also provide useful diagnostic targets for the identification of current and novel members of the indicated genera.
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14
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Ando-Suguimoto ES, da Silva MP, Kawamoto D, Chen C, DiRienzo JM, Mayer MPA. The cytolethal distending toxin of Aggregatibacter actinomycetemcomitans inhibits macrophage phagocytosis and subverts cytokine production. Cytokine 2014; 66:46-53. [PMID: 24548424 DOI: 10.1016/j.cyto.2013.12.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 11/19/2013] [Accepted: 12/24/2013] [Indexed: 02/06/2023]
Abstract
Aggregatibacter actinomycetemcomitans is an important periodontal pathogen that can participate in periodontitis and other non-oral infections. The cytolethal distending toxin (Cdt) is among the virulence factors produced by this bacterium. The Cdt is also secreted by several mucosa-associated Gram-negative pathogens and may play a role in perpetuating the infection by modulating the immune response. Although the toxin targets a wide range of eukaryotic cell types little is known about its activity on macrophages which play a key part in alerting the rest of the immune system to the presence of pathogens and their virulence factors. In view of this, we tested the hypothesis that the A. actinomycetemcomitans Cdt (AaCdt) disrupts macrophage function by inhibiting phagocytic activity as well as affecting the production of cytokines. Murine macrophages were co-cultured with either wild-type A. actinomycetemcomitans or a Cdt(-) mutant. Viable counts and qPCR showed that phagocytosis of the wild-type strain was significantly reduced relative to that of the Cdt(-) mutant. Addition of recombinant Aa(r)Cdt to co-cultures along with the Cdt(-) mutant diminished the phagocytic activity similar to that observed with the wild type strain. High concentrations of Aa(r)Cdt resulted in decreased phagocytosis of fluorescent bioparticles. Nitric oxide production was modulated by the presence of Cdt and the levels of IL-1β, IL-12 and IL-10 were increased. Production of TNF-α did not differ in the co-culture assays but was increased by the presence of Aa(r)Cdt. These data suggest that the Cdt may modulate macrophage function in A. actinomycetemcomitans infected sites by impairing phagocytosis and modifying the pro-inflammatory/anti-inflammatory cytokine balance.
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Affiliation(s)
| | - Maike Paulino da Silva
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Dione Kawamoto
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Casey Chen
- Division of Periodontology, Diagnostic Sciences and Dental Hygiene, Ostrow School of Dentistry of University of Southern California, USA
| | - Joseph M DiRienzo
- Department of Microbiology, School of Dental Medicine, University of Pennsylvania, PA, USA
| | - Marcia Pinto Alves Mayer
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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15
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Probing bacterial metabolism during infection using high-resolution transcriptomics. J Bacteriol 2013; 195:4991-8. [PMID: 23974023 DOI: 10.1128/jb.00875-13] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
A fundamental aspect of most infectious diseases is the need for the invading microbe to proliferate in the host. However, little is known about the metabolic pathways required for pathogenic microbes to colonize and persist in their hosts. In this study, we used RNA sequencing (RNA-seq) to generate a high-resolution transcriptome of the opportunistic pathogen Aggregatibacter actinomycetemcomitans in vivo. We identified 691 A. actinomycetemcomitans transcriptional start sites and 210 noncoding RNAs during growth in vivo and as a biofilm in vitro. Compared to in vitro biofilm growth on a defined medium, ∼14% of the A. actinomycetemcomitans genes were differentially regulated in vivo. A disproportionate number of genes coding for proteins involved in metabolic pathways were differentially regulated in vivo, suggesting that A. actinomycetemcomitans in vivo metabolism is distinct from in vitro growth. Mutational analyses of differentially regulated genes revealed that formate dehydrogenase H and fumarate reductase are important A. actinomycetemcomitans fitness determinants in vivo. These results not only provide a high-resolution genomic analysis of a bacterial pathogen during in vivo growth but also provide new insight into metabolic pathways required for A. actinomycetemcomitans in vivo fitness.
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Abstract
UNLABELLED Natural transformation by competent bacteria is a primary means of horizontal gene transfer; however, evidence that competence drives bacterial diversity and evolution has remained elusive. To test this theory, we used a retrospective comparative genomic approach to analyze the evolutionary history of Aggregatibacter actinomycetemcomitans, a bacterial species with both competent and noncompetent sister strains. Through comparative genomic analyses, we reveal that competence is evolutionarily linked to genomic diversity and speciation. Competence loss occurs frequently during evolution and is followed by the loss of clustered regularly interspaced short palindromic repeats (CRISPRs), bacterial adaptive immune systems that protect against parasitic DNA. Relative to noncompetent strains, competent bacteria have larger genomes containing multiple rearrangements. In contrast, noncompetent bacterial genomes are extremely stable but paradoxically susceptible to infective DNA elements, which contribute to noncompetent strain genetic diversity. Moreover, incomplete noncompetent strain CRISPR immune systems are enriched for self-targeting elements, which suggests that the CRISPRs have been co-opted for bacterial gene regulation, similar to eukaryotic microRNAs derived from the antiviral RNA interference pathway. IMPORTANCE The human microbiome is rich with thousands of diverse bacterial species. One mechanism driving this diversity is horizontal gene transfer by natural transformation, whereby naturally competent bacteria take up environmental DNA and incorporate new genes into their genomes. Competence is theorized to accelerate evolution; however, attempts to test this theory have proved difficult. Through genetic analyses of the human periodontal pathogen Aggregatibacter actinomycetemcomitans, we have discovered an evolutionary connection between competence systems promoting gene acquisition and CRISPRs (clustered regularly interspaced short palindromic repeats), adaptive immune systems that protect bacteria against genetic parasites. We show that competent A. actinomycetemcomitans strains have numerous redundant CRISPR immune systems, while noncompetent bacteria have lost their CRISPR immune systems because of inactivating mutations. Together, the evolutionary data linking the evolution of competence and CRISPRs reveals unique mechanisms promoting genetic heterogeneity and the rise of new bacterial species, providing insight into complex mechanisms underlying bacterial diversity in the human body.
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Huang Y, Kittichotirat W, Mayer MPA, Hall R, Bumgarner R, Chen C. Comparative genomic hybridization and transcriptome analysis with a pan-genome microarray reveal distinctions between JP2 and non-JP2 genotypes of Aggregatibacter actinomycetemcomitans. Mol Oral Microbiol 2012. [PMID: 23194436 DOI: 10.1111/omi.12005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
It was postulated that the highly virulent JP2 genotype of Aggregatibacter actinomycetemcomitans may possess a constellation of distinct virulence determinants not found in non-JP2 genotypes. This study compared the genome content and the transcriptome of the serotype b JP2 genotype and the closely related serotype b non-JP2 genotype of A. actinomycetemcomitans. A custom-designed pan-genomic microarray of A. actinomycetemcomitans was constructed and validated against a panel of 11 sequenced reference strains. The microarray was subsequently used for comparative genomic hybridization of serotype b strains of JP2 (six strains) and non-JP2 (six strains) genotypes, and for transcriptome analysis of strains of JP2 (three strains) and non-JP2 (two strains). Two JP2-specific and two non-JP2-specific genomic islands were identified. In one instance, distinct genomic islands were found to be inserted into the same locus among strains of different genotypes. Transcriptome analysis identified five operons, including the leukotoxin operon, to have at least two genes with an expression ratio of 2 or greater between genotypes. Two of the differentially expressed operons were members of the membrane-bound nitrate reductase system (nap operon) and the Tol-Pal system of gram-negative bacterial species. This study is the first to demonstrate the differences in the full genome content and gene expression between A. actinomycetemcomitans strains of JP2 and non-JP2 genotypes. The information is essential for designing hypothesis-driven experiments to examine the pathogenic mechanisms of A. actinomycetemcomitans.
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Affiliation(s)
- Y Huang
- Division of Periodontology, Diagnostic Sciences and Dental Hygiene, Ostrow School of Dentistry of USC, Los Angeles, CA, USA
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18
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Kikuchi H, Fujise O, Miura M, Tanaka A, Hisano K, Haraguchi A, Hamachi T, Maeda K. Serotype-dependent expression patterns of stabilized lipopolysaccharide aggregates inAggregatibacter actinomycetemcomitansstrains. Microbiol Immunol 2012; 56:680-91. [DOI: 10.1111/j.1348-0421.2012.00492.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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19
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Paino A, Lohermaa E, Sormunen R, Tuominen H, Korhonen J, Pöllänen MT, Ihalin R. Interleukin-1β is internalised by viable Aggregatibacter actinomycetemcomitans biofilm and locates to the outer edges of nucleoids. Cytokine 2012; 60:565-74. [PMID: 22898394 DOI: 10.1016/j.cyto.2012.07.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 06/15/2012] [Accepted: 07/17/2012] [Indexed: 10/28/2022]
Abstract
The opportunistic pathogen Aggregatibacter actinomycetemcomitans causes periodontitis, which is a biofilm infection that destroys tooth-supportive tissues. Interleukin (IL)-1β, a central proinflammatory cytokine of periodontitis, is an essential first line cytokine for local inflammation that modulates the cell proliferation and anti-pathogen response of human gingival keratinocytes. Previously, we demonstrated that A. actinomycetemcomitans biofilms bind IL-1β; however, whether this binding is an active process is not known. In this study, we showed for the first time with immuno-electron microscopy that viable bacterial biofilm cells internalised IL-1β when co-cultured with an organotypic mucosa. Decreased biofilm viability hindered the ability of biofilm to sequester IL-1β and caused IL-1β leakage into the culture medium. In some A. actinomycetemcomitans cells, intracellular IL-1β localized to the outer edges of the nucleoids. We identified the DNA-binding protein HU as an IL-1β interacting protein with mass spectroscopy and showed the interaction of recombinant HU and IL-1βin vitro using enzyme-linked immunosorbent assay (ELISA). Close contact with a viable A. actinomycetemcomitans biofilm decreased the proliferation and apoptosis of human gingival keratinocytes as demonstrated using Ki-67 and the terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) staining, respectively. Our results suggest that viable A. actinomycetemcomitans biofilms may disturb the critical first steps of local inflammation in periodontitis by binding and internalising IL-1β. The interaction of IL-1β with conserved HU provides a potential mechanism for shaping bacterial gene expression.
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Affiliation(s)
- Annamari Paino
- Department of Biochemistry and Food Chemistry, University of Turku, FI-20014 Turku, Finland
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20
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Zijnge V, Kieselbach T, Oscarsson J. Proteomics of protein secretion by Aggregatibacter actinomycetemcomitans. PLoS One 2012; 7:e41662. [PMID: 22848560 PMCID: PMC3405016 DOI: 10.1371/journal.pone.0041662] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 06/25/2012] [Indexed: 01/18/2023] Open
Abstract
The extracellular proteome (secretome) of periodontitis-associated bacteria may constitute a major link between periodontitis and systemic diseases. To obtain an overview of the virulence potential of Aggregatibacter actinomycetemcomitans, an oral and systemic human pathogen implicated in aggressive periodontitis, we used a combined LC-MS/MS and bioinformatics approach to characterize the secretome and protein secretion pathways of the rough-colony serotype a strain D7S. LC-MS/MS revealed 179 proteins secreted during biofilm growth. Further to confirming the release of established virulence factors (e.g. cytolethal distending toxin [CDT], and leukotoxin [LtxA]), we identified additional putative virulence determinants in the secretome. These included DegQ, fHbp, LppC, Macrophage infectivity protein (MIP), NlpB, Pcp, PotD, TolB, and TolC. This finding indicates that the number of extracellular virulence-related proteins is much larger than previously demonstrated, which was also supported by in silico analysis of the strain D7S genome. Moreover, our LC-MS/MS and in silico data revealed that at least Type I, II, and V secretion are actively used to excrete proteins directly into the extracellular space, or via two-step pathways involving the Sec/Tat systems for transport across the inner membrane, and outer membrane factors, secretins and auto-transporters, respectively for delivery across the outer membrane. Taken together, our results provide a molecular basis for further elucidating the role of A. actinomycetemcomitans in periodontal and systemic diseases.
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Affiliation(s)
- Vincent Zijnge
- Oral Microbiology, Department of Odontology, Umeå University, Umeå, Sweden
| | | | - Jan Oscarsson
- Oral Microbiology, Department of Odontology, Umeå University, Umeå, Sweden
- * E-mail:
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Jiang J, Li J, Kwan HS, Au CH, Wan Law PT, Li L, Kam KM, Lun Ling JM, Leung FC. A cost-effective and universal strategy for complete prokaryotic genomic sequencing proposed by computer simulation. BMC Res Notes 2012; 5:80. [PMID: 22289569 PMCID: PMC3296665 DOI: 10.1186/1756-0500-5-80] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Accepted: 01/31/2012] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Pyrosequencing techniques allow scientists to perform prokaryotic genome sequencing to achieve the draft genomic sequences within a few days. However, the assemblies with shotgun sequencing are usually composed of hundreds of contigs. A further multiplex PCR procedure is needed to fill all the gaps and link contigs into complete chromosomal sequence, which is the basis for prokaryotic comparative genomic studies. In this article, we study various pyrosequencing strategies by simulated assembling from 100 prokaryotic genomes. FINDINGS Simulation study shows that a single end 454 Jr. run combined with a paired end 454 Jr. run (8 kb library) can produce: 1) ~90% of 100 assemblies with < 10 scaffolds and ~95% of 100 assemblies with < 150 contigs; 2) average contig N50 size is over 331 kb; 3) average single base accuracy is > 99.99%; 4) average false gene duplication rate is < 0.7%; 5) average false gene loss rate is < 0.4%. CONCLUSIONS A single end 454 Jr. run combined with a paired end 454 Jr. run (8 kb library) is a cost-effective way for prokaryotic whole genome sequencing. This strategy provides solution to produce high quality draft assemblies for most of prokaryotic organisms within days. Due to the small number of assembled scaffolds, the following multiplex PCR procedure (for gap filling) would be easy. As a result, large scale prokaryotic whole genome sequencing projects may be finished within weeks.
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Affiliation(s)
- Jingwei Jiang
- School of Biological Sciences, Faculty of Science, The University of Hong Kong, Hong Kong, China.
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22
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Li J, Jiang J, Leung FC. 6-10× pyrosequencing is a practical approach for whole prokaryote genome studies. Gene 2011; 494:57-64. [PMID: 22192914 DOI: 10.1016/j.gene.2011.11.051] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 11/21/2011] [Indexed: 01/13/2023]
Abstract
Next generation 454 pyrosequencing technology for whole bacterial genome sequencing involves a deep sequencing strategy with at least 15-20× in depth proposed by official protocols but usually done with over 20× in practices. In this study, we carried out a comprehensive evaluation of quality of the de novo assemblies based on realistic pyrosequencing simulated data from 1480 prokaryote genomes and 7 runs of machine-generated data. Our results demonstrated that for most of the prokaryote genomes, 6-10× sequencing in qualified runs with 400 bp reads could produce high quality draft assembly (>98% genome coverage, <100 contigs with N50 size >100 kb, single base accuracy >99.99, indel error rate <0.01%, false gene loss/duplication rate <0.5%). Our study proves the power of low depth pyrosequencing strategy, which provides a cost-effective way for sequencing whole prokaryote genomes in a short time and enables further studies in microbial population diversity and comparative genomics.
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Affiliation(s)
- Jun Li
- School of Biological Sciences, Faculty of Science, The University of Hong Kong, China.
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Jiang J, Li J, Leung FC. A cost-effective and universal strategy for complete prokaryotic genome sequencing proposed by computer simulation. Genome Biol 2011. [DOI: 10.1186/1465-6906-12-s1-p6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Tanaka A, Fujise O, Chen C, Miura M, Hamachi T, Maeda K. A novel gene required for natural competence in Aggregatibacter actinomycetemcomitans. J Periodontal Res 2011; 47:129-34. [PMID: 21883229 DOI: 10.1111/j.1600-0765.2011.01410.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND OBJECTIVE Natural competence is the ability of bacteria to take up extracellular DNA and incorporate it into their genomes. Some strains of Aggregatibacter actinomycetemcomitans, a critical periodontal pathogen, are naturally competent for transformation. However, information on natural competence genes is limited for this species. The aim of this study was to confirm the involvement of a novel gene identified near the fimbriae gene cluster in natural competence. MATERIAL AND METHODS The functions of putative open reading frames (ORFs), designated AA00863-AA00865, in the Oralgen project database for A. actinomycetemcomitans strain HK1651, have not been determined. Using naturally transformable A. actinomycetemcomitans strains D7S-1 and ATCC29523, we created deletion mutants of homologous genes of these ORFs. Natural competence in the study strains was determined using an agar-based transformation frequency assay. RESULTS Mutation of the AA00865 homolog, which we named urpA in A. actinomycetemcomitans strain D7S-1, resulted in the loss of natural competence, whereas mutations of the AA00864 and AA00863 homologs, located downstream of urpA gene, did not. Similar results were also observed in the mutants of A. actinomycetemcomitans ATCC29523. Complementation of the deleted sequence in the urpA mutant restored natural competence. CONCLUSION The urpA gene is a novel gene required for natural competence in A. actinomycetemcomitans and does not exhibit significant homology with any natural competence genes previously identified in other bacterial species.
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Affiliation(s)
- A Tanaka
- Section of Periodontology, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
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Kittichotirat W, Bumgarner RE, Asikainen S, Chen C. Identification of the pangenome and its components in 14 distinct Aggregatibacter actinomycetemcomitans strains by comparative genomic analysis. PLoS One 2011; 6:e22420. [PMID: 21811606 PMCID: PMC3139650 DOI: 10.1371/journal.pone.0022420] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2011] [Accepted: 06/23/2011] [Indexed: 11/23/2022] Open
Abstract
Background Aggregatibacter actinomycetemcomitans is genetically heterogeneous and comprises distinct clonal lineages that may have different virulence potentials. However, limited information of the strain-to-strain genomic variations is available. Methodology/Principal Findings The genome sequences of 11 A. actinomycetemcomitans strains (serotypes a-f) were generated de novo, annotated and combined with three previously sequenced genomes (serotypes a-c) for comparative genomic analysis. Two major groups were identified; serotypes a, d, e, and f, and serotypes b and c. A serotype e strain was found to be distinct from both groups. The size of the pangenome was 3,301 genes, which included 2,034 core genes and 1,267 flexible genes. The number of core genes is estimated to stabilize at 2,060, while the size of the pangenome is estimated to increase by 16 genes with every additional strain sequenced in the future. Within each strain 16.7–29.4% of the genome belonged to the flexible gene pool. Between any two strains 0.4–19.5% of the genomes were different. The genomic differences were occasionally greater for strains of the same serotypes than strains of different serotypes. Furthermore, 171 genomic islands were identified. Cumulatively, 777 strain-specific genes were found on these islands and represented 61% of the flexible gene pool. Conclusions/Significance Substantial genomic differences were detected among A. actinomycetemcomitans strains. Genomic islands account for more than half of the flexible genes. The phenotype and virulence of A. actinomycetemcomitans may not be defined by any single strain. Moreover, the genomic variation within each clonal lineage of A. actinomycetemcomitans (as defined by serotype grouping) may be greater than between clonal lineages. The large genomic data set in this study will be useful to further examine the molecular basis of variable virulence among A. actinomycetemcomitans strains.
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Affiliation(s)
- Weerayuth Kittichotirat
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Roger E. Bumgarner
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Sirkka Asikainen
- Department of Surgical Sciences, Periodontology, Kuwait University, Kuwait City, Kuwait
| | - Casey Chen
- Division of Periodontology, Diagnostic Sciences and Dental Hygiene, Herman Ostrow School of Dentistry of the University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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Metabolite cross-feeding enhances virulence in a model polymicrobial infection. PLoS Pathog 2011; 7:e1002012. [PMID: 21483753 PMCID: PMC3069116 DOI: 10.1371/journal.ppat.1002012] [Citation(s) in RCA: 174] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 01/26/2011] [Indexed: 11/19/2022] Open
Abstract
Microbes within polymicrobial infections often display synergistic interactions resulting in enhanced pathogenesis; however, the molecular mechanisms governing these interactions are not well understood. Development of model systems that allow detailed mechanistic studies of polymicrobial synergy is a critical step towards a comprehensive understanding of these infections in vivo. In this study, we used a model polymicrobial infection including the opportunistic pathogen Aggregatibacter actinomycetemcomitans and the commensal Streptococcus gordonii to examine the importance of metabolite cross-feeding for establishing co-culture infections. Our results reveal that co-culture with S. gordonii enhances the pathogenesis of A. actinomycetemcomitans in a murine abscess model of infection. Interestingly, the ability of A. actinomycetemcomitans to utilize L-lactate as an energy source is essential for these co-culture benefits. Surprisingly, inactivation of L-lactate catabolism had no impact on mono-culture growth in vitro and in vivo suggesting that A. actinomycetemcomitans L-lactate catabolism is only critical for establishing co-culture infections. These results demonstrate that metabolite cross-feeding is critical for A. actinomycetemcomitans to persist in a polymicrobial infection with S. gordonii supporting the idea that the metabolic properties of commensal bacteria alter the course of pathogenesis in polymicrobial communities. Many bacterial infections are not the result of colonization and persistence of a single pathogenic microbe in an infection site but instead the result of colonization by several. Although the importance of polymicrobial interactions and pathogenesis has been noted by many prominent microbiologists including Louis Pasteur, most studies of pathogenic microbes have focused on single organism infections. One of the primary reasons for this oversight is the lack of robust model systems for studying bacterial interactions in an infection site. Here, we use a model co-culture system composed of the opportunistic oral pathogen Aggregatibacter actinomycetemcomitans and the common oral commensal Streptococcus gordonii to assess the impact of polymicrobial growth on pathogenesis. We found that the abilities of A. actinomycetemcomitans to persist and cause disease are enhanced during co-culture with S. gordonii. Remarkably, this enhanced persistence requires A. actinomycetemcomitans catabolism of L-lactate, the primary metabolite produced by S. gordonii. These data demonstrate that during co-culture growth, S. gordonii provides a carbon source for A. actinomycetemcomitans that is necessary for establishing a robust polymicrobial infection. This study also demonstrates that virulence of an opportunistic pathogen is impacted by members of the commensal flora.
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Pinheiro ET, Kawamoto D, Ota-Tsuzuki C, Almeida LRS, Nunes ACR, Longo PL, Wikstrom M, Mayer MPA. Analysis of genotypic variation in genes associated with virulence in Aggregatibacter actinomycetemcomitans clinical isolates. J Periodontal Res 2011; 46:310-7. [DOI: 10.1111/j.1600-0765.2011.01344.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Freire MO, Sedghizadeh PP, Schaudinn C, Gorur A, Downey JS, Choi JH, Chen W, Kook JK, Chen C, Goodman SD, Zadeh HH. Development of an animal model for Aggregatibacter actinomycetemcomitans biofilm-mediated oral osteolytic infection: a preliminary study. J Periodontol 2011; 82:778-89. [PMID: 21222546 DOI: 10.1902/jop.2010.100263] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Biofilm-induced inflammatory osteolytic oral infections, such as periodontitis and peri-implantitis, have complex etiology and pathogenesis. A significant obstacle to research has been the lack of appropriate animal models where the inflammatory response to biofilms can be investigated. The aim of this study is to develop a novel animal model to study the host response to Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans)-biofilm colonizing titanium implants. METHODS Titanium implants were inoculated in vitro with A. actinomycetemcomitans, establishing a biofilm for 1 to 3 days. Biofilm-inoculated and control implants were transmucosally placed into rat hard palate or alveolar ridge. Analysis included documentation of clinical inflammation, polymerase chain reaction, and culture detection of A. actinomycetemcomitans and microcomputed tomography quantitation of peri-implant bone volume. RESULTS Viable A. actinomycetemcomitans biofilm was successfully established on titanium implants in vitro, detected by confocal laser scanning microscopy. An inflammatory response characterized by clinical inflammation, bleeding, ulceration, hyperplasia, and necrosis was observed around biofilm-inoculated implants. A. actinomycetemcomitans was detected by polymerase chain reaction and culture analysis on 100% of biofilm-inoculated implants for up to 3 weeks and 25% for up to 6 weeks. Microcomputed tomography analysis demonstrated significantly lower bone volume (P <0.05) around biofilm-inoculated implants (29.6% ± 7.6%) compared to non-inoculated implants (50.5% ± 9.6%) after 6 weeks. CONCLUSIONS These results describe a novel animal model where A. actinomycetemcomitans biofilm was established in vitro on titanium implants before placement in rat oral cavity, leading to an inflammatory response, osteolysis, and tissue destruction. This model may have potential use for investigation of host responses to biofilm pathogens and antibiofilm therapy.
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Affiliation(s)
- Marcelo O Freire
- Division of Periodontology, Diagnostic Sciences and Dental Hygiene, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA 90089, USA
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Kittichotirat W, Bumgarner R, Chen C. Markedly different genome arrangements between serotype a strains and serotypes b or c strains of Aggregatibacter actinomycetemcomitans. BMC Genomics 2010; 11:489. [PMID: 20825670 PMCID: PMC2996985 DOI: 10.1186/1471-2164-11-489] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 09/08/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Bacterial phenotype may be profoundly affected by the physical arrangement of their genes in the genome. The Gram-negative species Aggregatibacter actinomycetemcomitans is a major etiologic agent of human periodontitis. Individual clonal types of A. actinomycetemcomitans may exhibit variable virulence and different patterns of disease association. This study examined the genome arrangement of A. actinomycetemcomitans using the genome sequences of serotypes a-c strains. The genome alignment and rearrangement were analyzed by the MAUVE and the GRIMM algorithms. The distribution patterns of genes along the leading/lagging strands were investigated. The occurrence and the location of repeat sequences relative to the genome rearrangement breakpoints were also determined. RESULTS The genome arrangement of the serotype a strain D7S-1 is markedly different from the serotype b strain HK1651 or the serotype c strain D11S-1. Specific genome arrangements appear to be conserved among strains of the same serotypes. The reversal distance between D7S-1 and HK1651 by GRIMM analysis is also higher than the within-species comparisons of 7 randomly selected bacterial species. The locations of the orthologous genes are largely preserved between HK1651 and D11S-1 but not between D7S-1 and HK1651 (or D11S-1), irrespective of whether the genes are categorized as essential/nonessential or highly/nonhighly expressed. However, genome rearrangement did not disrupt the operons of the A. actinomycetemcomitans strains. A higher proportion of the genome in strain D7S-1 is occupied by repeat sequences than in strains HK1651 or D11S-1. CONCLUSION The results suggest a significant evolutionary divergence between serotype a strains and serotypes b/c strains of A. actinomycetemcomitans. The distinct patterns of genome arrangement may suggest phenotypic differences between serotype a and serotypes b/c strains.
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Affiliation(s)
- Weerayuth Kittichotirat
- Division of Periodontology, Diagnostic Sciences and Dental Hygiene, Herman Ostrow School of Dentistry of the University of Southern California, Los Angeles, CA, USA
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