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Carriage of the JP2 Genotype of Aggregatibacter actinomycetemcomitans by Periodontitis Patients of Various Geographic Origin, Living in Sweden. Pathogens 2022; 11:pathogens11111233. [PMID: 36364984 PMCID: PMC9697931 DOI: 10.3390/pathogens11111233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/14/2022] [Accepted: 10/24/2022] [Indexed: 11/17/2022] Open
Abstract
The JP2 genotype of Aggregatibacter actinomycetemcomitans serotype b is associated with aggressive forms of periodontitis and was initially identified as affecting adolescents in North and West Africa. The dissemination of this genotype follows the migration routes and can today be detected in samples from periodontitis patients in a high number of countries. In the present study, we aim to describe findings of the JP2 genotype A. actinomycetemcomits in a clinical laboratory at the Dental School, Odontology, Umeå University, Sweden. The findings of JP2 carriers are documented during a 21-year period, and the age and geographic origin of the sampled individuals are described. In addition, the collected JP2 isolates were separated into North or West African origin by analyses of the presence of a point mutation in the hbpA2 pseudogene of the bacterium. In a total of 2296 sampled individuals during this period in this Swedish population of periodontitis patients, 32 JP2 carriers were detected by cultivation and PCR. The geographic background of these individuals was diverse, including sixteen with African origin, ten with a Swedish origin and six additional ones with a non-African origin. The JP2 genotypes of A. actinomycetemcomitans were mainly isolated from young individuals (<35 years of age), and seven out of the 32 isolates were of a West African origin based on the sequence of hbpA2. We conclude that the JP2 genotype of A. actinomycetemcomitans can be detected world-wide in subgingival plaque samples from adolescents affected by periodontitis.
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Claesson R, Chiang HM, Lindholm M, Höglund Åberg C, Haubek D, Johansson A, Oscarsson J. Characterization of Aggregatibacter actinomycetemcomitans Serotype b Strains with Five Different, Including Two Novel, Leukotoxin Promoter Structures. Vaccines (Basel) 2020; 8:vaccines8030398. [PMID: 32698444 PMCID: PMC7563764 DOI: 10.3390/vaccines8030398] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/15/2020] [Accepted: 07/16/2020] [Indexed: 01/23/2023] Open
Abstract
The JP2 genotype of A. actinomycetemcomitans, serotype b has attracted much interest during the past three decades due to its close association with periodontitis in young individuals and the enhanced expression of a leukotoxin (LtxA). A typical feature of this genotype is a 530-base pair (bp) deletion in the ltxCABD promoter region controlling leukotoxin expression. In the present work, we have characterized serotype b strains with four additional promoter types. Two novel types have been recognized, that is, one with a 230-bp deletion and one with a 172-bp duplication. Moreover, a strain with a 640-bp deletion and three strains with a full-length promoter, including the type strain Y4, were included in the present study. The seven strains were characterized by multi locus sequence typing (MLST) and arbitrarily primed polymerase chain reaction (PCR) and assessed for LtxA production. MLST showed that the strains with the non-JP2-like deletions represented distinct monophyletic groups, whereas the JP2 strain, HK1651, represented a separate branch. LtxA production was high in all three strains with a promoter deletion, whereas the other four strains showed significantly lower levels. It can be concluded that the genetic characterization and determination of LtxA production of A. actinomycetemcomitans isolates from individuals with periodontitis can contribute to the identification of novel virulent genotypes of this bacterium.
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Affiliation(s)
- Rolf Claesson
- Division of Oral Microbiology, Department of Odontology, Umeå University, S-90187 Umeå, Sweden; (M.L.); (J.O.)
- Correspondence:
| | - Huei-Min Chiang
- Division of Molecular Periodontology, Department of Odontology, Umeå University, S-90187 Umeå, Sweden; (H.-M.C.); (C.H.Å.); (A.J.)
| | - Mark Lindholm
- Division of Oral Microbiology, Department of Odontology, Umeå University, S-90187 Umeå, Sweden; (M.L.); (J.O.)
| | - Carola Höglund Åberg
- Division of Molecular Periodontology, Department of Odontology, Umeå University, S-90187 Umeå, Sweden; (H.-M.C.); (C.H.Å.); (A.J.)
| | - Dorte Haubek
- Section for Paediatric Dentistry, Department of Dentistry and Oral Health, Aarhus University, 8000 Aarhus, Denmark;
| | - Anders Johansson
- Division of Molecular Periodontology, Department of Odontology, Umeå University, S-90187 Umeå, Sweden; (H.-M.C.); (C.H.Å.); (A.J.)
| | - Jan Oscarsson
- Division of Oral Microbiology, Department of Odontology, Umeå University, S-90187 Umeå, Sweden; (M.L.); (J.O.)
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Cranberry Proanthocyanidins Neutralize the Effects of Aggregatibacter actinomycetemcomitans Leukotoxin. Toxins (Basel) 2019; 11:toxins11110662. [PMID: 31739483 PMCID: PMC6891731 DOI: 10.3390/toxins11110662] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/07/2019] [Accepted: 11/08/2019] [Indexed: 01/14/2023] Open
Abstract
Aggregatibacter actinomycetemcomitans is a Gram-negative bacterium that has been strongly associated with localized aggressive periodontitis. The capacity of A. actinomycetemcomitans to produce a leukotoxin (LtxA) that activates pyroptosis in macrophages and induces the release of endogenous danger signals is thought to play a key role in the disease process. The aim of the present study was to investigate the effects of cranberry proanthocyanidins (PACs) on gene expression and cytotoxic activities of LtxA. We showed that cranberry PACs dose-dependently attenuate the expression of genes making up the leukotoxin operon, including ltxB and ltxC, in the two strains of A. actinomycetemcomitans tested. Cranberry PACs (≥62.5 µg/mL) protected macrophages against the cytotoxic effect of purified LtxA. Moreover, cranberry PACs reduced caspase-1 activation in LtxA-treated macrophages and consequently decreased the release of both IL-1β and IL-18, which are known as damage-associated molecular patterns (DAMPs) and contribute to the progression of periodontitis by increasing cell migration and osteoclastogenesis. In addition, cranberry PACs reduced the expression of genes encoding the P2X7 receptor and NALP3 (NACHT, LRR and PYD domains-containing protein 3), which play key roles in pore formation and cell death. Lastly, cranberry PACs blocked the binding of LtxA to macrophages and consequently reduced the LtxA-mediated cytotoxicity. In summary, the present study showed that cranberry PACs reduced LtxA gene expression in A. actinomycetemcomitans and neutralized the cytolytic and pro-inflammatory responses of human macrophages treated with LtxA. Given these properties, cranberry PACs may represent promising molecules for prevention and treatment of the aggressive form of periodontitis caused by A. actinomycetemcomitans.
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Ben Lagha A, LeBel G, Grenier D. Dual action of highbush blueberry proanthocyanidins on Aggregatibacter actinomycetemcomitans and the host inflammatory response. Altern Ther Health Med 2018; 18:10. [PMID: 29321009 PMCID: PMC5763534 DOI: 10.1186/s12906-017-2072-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 12/27/2017] [Indexed: 01/06/2023]
Abstract
Background The highbush blueberry (Vaccinium corymbosum) has a beneficial effect on several aspects of human health. The present study investigated the effects of highbush blueberry proanthocyanidins (PACs) on the virulence properties of Aggregatibacter actinomycetemcomitans and macrophage-associated inflammatory responses. Methods PACs were isolated from frozen highbush blueberries using solid-phase chromatography. A microplate dilution assay was performed to determine the effect of highbush blueberry PACs on A. actinomycetemcomitans growth as well as biofilm formation stained with crystal violet. Tight junction integrity of oral keratinocytes was assessed by measuring the transepithelial electrical resistance (TER), while macrophage viability was determined with a colorimetric MTT assay. Pro-inflammatory cytokine and MMP secretion by A. actinomycetemcomitans-stimulated macrophages was quantified by ELISA. The U937-3xκB-LUC monocyte cell line transfected with a luciferase reporter gene was used to monitor NF-κB activation. Results Highbush blueberry PACs reduced the growth of A. actinomycetemcomitans and prevented biofilm formation at sub-inhibitory concentrations. The treatment of pre-formed biofilms with the PACs resulted in a loss of bacterial viability. The antibacterial activity of the PACs appeared to involve damage to the bacterial cell membrane. The PACs protected the oral keratinocytes barrier integrity from damage caused by A. actinomycetemcomitans. The PACs also protected macrophages from the deleterious effect of leukotoxin Ltx-A and dose-dependently inhibited the secretion of pro-inflammatory cytokines (IL-1β, IL-6, CXCL8, TNF-α), matrix metalloproteinases (MMP-3, MMP-9), and sTREM-1 by A. actinomycetemcomitans-treated macrophages. The PACs also inhibited the activation of the NF-κB signaling pathway. Conclusion The antibacterial and anti-inflammatory properties of highbush blueberry PACs as well as their ability to protect the oral keratinocyte barrier and neutralize leukotoxin activity suggest that they may be promising candidates as novel therapeutic agents.
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Claesson R, Höglund-Åberg C, Haubek D, Johansson A. Age-related prevalence and characteristics of Aggregatibacter actinomycetemcomitans in periodontitis patients living in Sweden. J Oral Microbiol 2017; 9:1334504. [PMID: 28748039 PMCID: PMC5508378 DOI: 10.1080/20002297.2017.1334504] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 05/11/2017] [Indexed: 02/08/2023] Open
Abstract
Background: The presence of Aggregatibacter actinomycetemcomitans in patients with periodontitis has been extensively studied for decades. Objective: To study the prevalence of A. actinomycetemcomitans in younger and older periodontitis patients and to genetically characterize isolates of this bacterium. Design: Data from microbiological analyses of 3459 subgingival plaque samples collected from 1445 patients, 337 ‘younger’ patients (≤35 yrs) and 1108 ‘older’ patients (>35 yrs) during 15 years (2000–2014), has been summerized. Isolates of A. actinomycetemcomitans were serotyped, leukotoxin promoter typed (JP2 and non JP2) and arbitrarily primed PCR (AP-PCR) genotyped. The origin of the JP2 genotype detected in the study population was determined. Results: The prevalence of A. actinomycetemcomitans was higher among younger than older patients and samples from the younger patients contained higher proportions of the bacterium. Serotype b was more prevalent among younger patients and the majorty of these isolates was from the same AP-PCR genotype. The JP2 genotype was detected in 1.2% of the patients, and the majority of these carriers were of non-African origin. Conslusions: For presence and charcteristics of A. actinomycetemcomitans in clinical samples the age of the carriers were a discriminating factor. Additional, apparently non-African carriers of the JP2 genotype of A. actinomycetemcomitans were identified.
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Affiliation(s)
- Rolf Claesson
- Division of Oral Microbiology, Department of Odontology, Umeå University, Umeå, Sweden
| | - Carola Höglund-Åberg
- Division of Molecular Periodontology, Department of Odontology, Umeå University, Umeå, Sweden
| | - Dorte Haubek
- Section for Pediatric Dentistry, Department of Dentistry, Health, Aarhus UniversityAarhus, Denmark
| | - Anders Johansson
- Division of Molecular Periodontology, Department of Odontology, Umeå University, Umeå, Sweden
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Jaffar N, Miyazaki T, Maeda T. Biofilm formation of periodontal pathogens on hydroxyapatite surfaces: Implications for periodontium damage. J Biomed Mater Res A 2016; 104:2873-80. [PMID: 27390886 DOI: 10.1002/jbm.a.35827] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 06/24/2016] [Accepted: 07/06/2016] [Indexed: 11/05/2022]
Abstract
Biofilm formation of periodontal pathogens on teeth surfaces promotes the progression of periodontal disease. Hence, understanding the mechanisms of bacterial attachment to the dental surfaces may inform strategies for the maintenance of oral health. Although hydroxyapatite (HA) is a major calcium phosphate component of teeth, effect of biofilm formation on HA surfaces remains poorly characterized. In this study, biofilm-forming abilities by the periodontal pathogens Aggregatibacter actinomycetemcomitans Y4 and Porphyromonas gingivalis 381 were investigated on dense and porous HAs that represent enamel and dentin surfaces, respectively. These experiments showed greater biofilm formation on porous HA, but differing attachment profiles and effects of the two pathogens. Specifically, while the detachment of A. actinomycetemcomitans Y4 biofilm was observed, P. gingivalis 381 biofilm increased with time. Moreover, observations of HA morphology following formation of A. actinomycetemcomitans Y4 biofilm revealed gaps between particles, whereas no significant changes were observed in the presence of P. gingivalis 381. Finally, comparisons of calcium leakage showed only slight differences between bacterial species and HA types and may be masked by bacterial calcium uptake. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2873-2880, 2016.
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Affiliation(s)
- Norzawani Jaffar
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka, 808-0196, Japan.,Faculty of Health Sciences, Gong Badak Campus, Universiti Sultan Zainal Abidin (UniSZA), Kuala Terengganu, Terengganu Darul Iman, Malaysia
| | - Toshiki Miyazaki
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka, 808-0196, Japan
| | - Toshinari Maeda
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka, 808-0196, Japan. .,Research Center for Advanced Eco-Fitting Technology, Kyushu Institute of Technology, Kitakyushu, Japan.
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Abstract
Aggregatibacter actinomycetemcomitans is a gram-negative microbe involved in periodontitis. Strains with varying degrees of virulence have been identified, in healthy and periodontally compromised individuals alike. Hosts mount differential immune responses to its various serotypes and virulence factors. Studies have explored host immune response in terms of antibody titers, leukocyte responses, and specific inflammatory mediators, questioning the ways in which the infectious microorganism survives. This mini-review will identify the key themes in immune response patterns of individuals both affected by and free from aggressive periodontal disease, thereby using it to understand various forms of periodontitis.
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Affiliation(s)
- Nishat Shahabuddin
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, USA; Departments of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, USA
| | - Kathleen Boesze-Battaglia
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, USA
| | - Edward T Lally
- Departments of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, USA
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Jensen AB, Ennibi OK, Ismaili Z, Poulsen K, Haubek D. The JP2 genotype of Aggregatibacter actinomycetemcomitans
and marginal periodontitis in the mixed dentition. J Clin Periodontol 2016; 43:19-25. [PMID: 26659719 DOI: 10.1111/jcpe.12486] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2015] [Indexed: 10/25/2022]
Affiliation(s)
- Anne Birkeholm Jensen
- Section for Pediatric Dentistry; Department of Dentistry, Health; Aarhus University; Aarhus Denmark
| | - Oum Keltoum Ennibi
- Department of Periodontology; Faculty of Medicine Dentistry; Mohammed V Souissi University; Rabat Morocco
| | - Zouheir Ismaili
- Department of Periodontology; Faculty of Medicine Dentistry; Mohammed V Souissi University; Rabat Morocco
| | - Knud Poulsen
- Department of Biomedicine, Health; Aarhus University; Aarhus Denmark
| | - Dorte Haubek
- Section for Pediatric Dentistry; Department of Dentistry, Health; Aarhus University; Aarhus Denmark
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Najafi S, Khayamzadeh M, Paknejad M, Poursepanj G, Kharazi Fard MJ, Bahador A. An In Vitro Comparison of Antimicrobial Effects of Curcumin-Based Photodynamic Therapy and Chlorhexidine, on Aggregatibacter actinomycetemcomitans. J Lasers Med Sci 2016; 7:21-5. [PMID: 27330693 DOI: 10.15171/jlms.2016.05] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
INTRODUCTION Considering the importance of prevention in periodontal diseases and the important role of Aggregatibacter actinomycetemcomitans in induction and progression of these diseases, the aim of the present in vitro study was to compare the antimicrobial effects of chlorhexidine digluconate (CHX), curcumin and light-emitting diode (LED) laser, on this bacterium. METHODS Antimicrobial activity of curcumin (5 mg/ml), CHX (2%), LED (120 J/cm(2)) and LED + curcumin (120 J/cm(2) + 2.5 mg/ml) against A. actinomycetemcomitans were tested in vitro, using micro-broth dilution test. One-way analysis of variance (ANOVA) and Tukey's HSD tests served for statistical analysis. RESULTS Regarding the minimum inhibitory concentration (MIC), CHX had a significantly lower MIC than curcumin (P < 0.05). Sorted out by bacterial growth from lowest to highest, were CHX, LED + curcumin, curcumin, and LED groups. All the differences were found to be statistically significant (P < 0.05) except for the LED group. CONCLUSION We conclude that curcumin is an effective substance in preventing the growth of A. actinomycetemcomitans, whose impact is reinforced when used simultaneously with photodynamic therapy (PDT).
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Affiliation(s)
- Shamsoulmolouk Najafi
- Department of Oral Medicine, International Campus, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran ; Department of Dental Research Center and Oral Medicine, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Mina Khayamzadeh
- Department of Oral Medicine, International Campus, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Mojgan Paknejad
- Department of Periodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Golfam Poursepanj
- International Campus, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Abbas Bahador
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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Claesson R, Gudmundson J, Åberg CH, Haubek D, Johansson A. Detection of a 640-bp deletion in the Aggregatibacter actinomycetemcomitans leukotoxin promoter region in isolates from an adolescent of Ethiopian origin. J Oral Microbiol 2015; 7:26974. [PMID: 25881573 PMCID: PMC4400299 DOI: 10.3402/jom.v7.26974] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Revised: 03/03/2015] [Accepted: 03/10/2015] [Indexed: 11/17/2022] Open
Abstract
The expression of the leukotoxin of Aggregatibacter actinomycetemcomitans is regulated by the leukotoxin promoter. A 530-bp deletion or an 886-bp insertion sequence (IS) element in this region has earlier been described in highly leukotoxic isolates. Here, we report on highly leukotoxic isolate with a 640-bp deletion, which was detected in an adolescent of Ethiopian origin.
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Affiliation(s)
- Rolf Claesson
- Division of Oral Microbiology, Department of Odontology, Umeå University, Umeå, Sweden;
| | - Jan Gudmundson
- Periodontology Specialist Clinic, Östersunds Hospital, Östersund, Sweden
| | - Carola Höglund Åberg
- Division of Molecular Periodontology, Department of Odontology, Umeå University, Umeå, Sweden
| | - Dorte Haubek
- Section for Pediatric Dentistry, Department of Dentistry, Health, Aarhus University, Aarhus, Denmark
| | - Anders Johansson
- Division of Molecular Periodontology, Department of Odontology, Umeå University, Umeå, Sweden
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Haubek D, Johansson A. Pathogenicity of the highly leukotoxic JP2 clone of Aggregatibacter actinomycetemcomitans and its geographic dissemination and role in aggressive periodontitis. J Oral Microbiol 2014; 6:23980. [PMID: 25206940 PMCID: PMC4139931 DOI: 10.3402/jom.v6.23980] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 07/03/2014] [Accepted: 07/07/2014] [Indexed: 02/01/2023] Open
Abstract
For decades, Aggregatibacter actinomycetemcomitans has been associated with aggressive forms of periodontitis in adolescents. In the middle of the 1990s, a specific JP2 clone of A. actinomycetemcomitans, belonging to the cluster of serotype b strains of A. actinomycetemcomitans and having a number of other characteristics, was found to be strongly associated with aggressive forms of periodontitis, particularly in North Africa. Although several longitudinal studies still point to the bacterial species, A. actinomycetemcomitans as a risk factor of aggressive periodontitis, it is now also widely accepted that the highly leukotoxic JP2 clone of A. actinomycetemcomitans is implicated in rapidly progressing forms of aggressive periodontitis. The JP2 clone strains are highly prevalent in human populations living in Northern and Western parts of Africa. These strains are also prevalent in geographically widespread populations that have originated from the Northwest Africa. Only sporadic signs of a dissemination of the JP2 clone strains to non-African populations have been found despite Africans living geographically widespread for hundreds of years. It remains an unanswered question if a particular host tropism exists as a possible explanation for the frequent colonization of the Northwest African population with the JP2 clone. Two exotoxins of A. actinomycetemcomitans are known, leukotoxin (LtxA) and cytolethal distending toxin (Cdt). LtxA is able to kill human immune cells, and Cdt can block cell cycle progression in eukaryotic cells and thus induce cell cycle arrest. Whereas the leukotoxin production is enhanced in JP2 clone strains thus increasing the virulence potential of A. actinomycetemcomitans, it has not been possible so far to demonstrate such a role for Cdt. Lines of evidence have led to the understanding of the highly leukotoxic JP2 clone of A. actinomycetemcomitans as an aetiological factor of aggressive periodontitis. Patients, who are colonized with the JP2 clone, are likely to share this clone with several family members because the clone is transmitted through close contacts. This is a challenge to the clinicians. The patients need intense monitoring of their periodontal status as the risk for developing severely progressing periodontal lesions are relatively high. Furthermore, timely periodontal treatment, in some cases including periodontal surgery supplemented by the use of antibiotics, is warranted. Preferably, periodontal attachment loss should be prevented by early detection of the JP2 clone of A. actinomycetemcomitans by microbial diagnostic testing and/or by preventive means.
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Affiliation(s)
- Dorte Haubek
- Section for Pediatric Dentistry, Department of Dentistry, Health, Aarhus University, Aarhus, Denmark
| | - Anders Johansson
- Department of Molecular Periodontology, Umea University, Umea, Sweden
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Höglund Åberg C, Haubek D, Kwamin F, Johansson A, Claesson R. Leukotoxic activity of Aggregatibacter actinomycetemcomitans and periodontal attachment loss. PLoS One 2014; 9:e104095. [PMID: 25093857 PMCID: PMC4122431 DOI: 10.1371/journal.pone.0104095] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 07/08/2014] [Indexed: 11/19/2022] Open
Abstract
Aggregatibacter actinomycetemcomitans is a Gram-negative periodontitis-associated bacterium that expresses a toxin that selectively affects leukocytes. This leukotoxin is encoded by an operon belonging to the core genome of this bacterial species. Variations in the expression of the leukotoxin have been reported, and a well-characterized specific clonal type (JP2) of this bacterium with enhanced leukotoxin expression has been isolated. In particular, the presence of the JP2 genotype significantly increases the risk for the progression of periodontal attachment loss (AL). Based on these findings we hypothesized that variations in the leukotoxicity are linked to disease progression in infected individuals. In the present study, the leukotoxicity of 239 clinical isolates of A. actinomycetemcomitans was analysed with different bioassays, and the genetic peculiarities of the isolates were related to their leukotoxicity based on examination with molecular techniques. The periodontal status of the individuals sampled for the presence of A. actinomycetemcomitans was examined longitudinally, and the importance of the observed variations in leukotoxicity was evaluated in relation to disease progression. Our data show that high leukotoxicity correlates with an enhanced risk for the progression of AL. The JP2 genotype isolates were all highly leukotoxic, while the isolates with an intact leukotoxin promoter (non-JP2 genotypes) showed substantial variation in leukotoxicity. Genetic characterization of the non-JP2 genotype isolates indicated the presence of highly leukotoxic genotypes of serotype b with similarities to the JP2 genotype. Based on these results, we conclude that A. actinomycetemcomitans harbours other highly virulent genotypes besides the previously described JP2 genotype. In addition, the results from the present study further highlight the importance of the leukotoxin as a key virulence factor in aggressive forms of periodontitis.
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Affiliation(s)
- Carola Höglund Åberg
- Division of Molecular Periodontology, Department of Odontology, Faculty of Medicine, Umeå University, Umeå, Sweden
| | - Dorte Haubek
- Section for Pediatric Dentistry, Department of Dentistry, Health, Aarhus University, Aarhus, Denmark
| | | | - Anders Johansson
- Division of Molecular Periodontology, Department of Odontology, Faculty of Medicine, Umeå University, Umeå, Sweden
| | - Rolf Claesson
- Oral Microbiology, Department of Odontology, Faculty of Medicine, Umeå University, Umeå, Sweden
- * E-mail:
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Moslemi N, Soleiman-Zadeh Azar P, Bahador A, Rouzmeh N, Chiniforush N, Paknejad M, Fekrazad R. Inactivation of Aggregatibacter actinomycetemcomitans by two different modalities of photodynamic therapy using Toluidine blue O or Radachlorin as photosensitizers: an in vitro study. Lasers Med Sci 2014; 30:89-94. [PMID: 24981641 DOI: 10.1007/s10103-014-1621-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Accepted: 06/22/2014] [Indexed: 12/24/2022]
Abstract
Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) is one of the periodontopathogens strongly associated with aggressive periodontitis. The aim of this investigation was to compare the effect of laser and light-emitting diode on the photodynamic inactivation of A. actinomycetemcomitans. Eighty-four samples of bacterial suspensions (200 μL) were prepared and divided in seven groups: control group (no treatment), laser group (indium-gallium-aluminum-phosphate laser with wavelength of 662 ± 0.1 nm, energy density of 6 j/cm(2), and irradiation time of 34 s), light-emitting diode (LED) group (wavelength 625-635 nm, energy density 6 j/cm(2), time of irradiation 30 s), Toluidine blue O (TBO) group (0.1 mg/mL), Radachlorin group (0.1 %), Radachlorin + laser group (after pre-irradiation time of 10 min, laser was irradiated), and TBO + LED group (after preirradiation time of 10 min, LED was irradiated). Then, 100 μL of each sample was cultured in brain heart infusion (BHI) plates and incubated for 48-72 h in microaerophilic atmosphere for colony counting. Application of Radachlorin + laser resulted in a significant decrease in the concentration of A. actinomycetemcomitans (P values <0.05). Photodynamic therapy with laser + Radachlorin was more effective than that of LED + TBO in suppression of this microorganism (P value <0.05). Within the limits of this study, it can be concluded that photodynamic inactivation using laser and Radachlorin was more effective than that of LED and TBO in eradication of A. actinomycetemcomitans.
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Affiliation(s)
- Neda Moslemi
- Laser Research Center of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
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Action of natural products on p2 receptors: a reinvented era for drug discovery. Molecules 2012; 17:13009-25. [PMID: 23117439 PMCID: PMC6268057 DOI: 10.3390/molecules171113009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 10/12/2012] [Accepted: 10/24/2012] [Indexed: 12/15/2022] Open
Abstract
Natural products contribute significantly to available drug therapies and have been a rich source for scientific investigation. In general, due to their low cost and traditional use in some cultures, they are an object of growing interest as alternatives to synthetic drugs. With several diseases such as cancer, and inflammatory and neuropathic diseases having been linked to the participation of purinergic (P2) receptors, there has been a flurry of investigations on ligands within natural products. Thirty-four different sources of these compounds have been found so far, that have shown either agonistic or antagonistic effects on P2 receptors. Of those, nine different plant sources demonstrated effects on P2X2, P2X3, P2X7, and possibly P2Y12 receptor subtypes. Microorganisms, which represent the largest group, with 26 different sources, showed effects on both receptor subtypes, ranging from P2X1 to P2X4 and P2X7, and P2Y1, P2Y2, P2Y4, and P2Y6. In addition, there were seventeen animal sources that affected P2X7 and P2Y1 and P2Y12 receptors. Natural products have provided some fascinating new mechanisms and sources to better understand the P2 receptor antagonism. Moreover, current investigations should clarify further pharmacological mechanisms in order to consider these products as potential new medicines.
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Kelk P, Abd H, Claesson R, Sandström G, Sjöstedt A, Johansson A. Cellular and molecular response of human macrophages exposed to Aggregatibacter actinomycetemcomitans leukotoxin. Cell Death Dis 2011; 2:e126. [PMID: 21390060 PMCID: PMC3101819 DOI: 10.1038/cddis.2011.6] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Aggregatibacter (Actinobacillus) actinomycetemcomitans is a facultative anaerobic gram-negative bacterium associated with severe forms of periodontitis. A leukotoxin, which belongs to the repeats-in-toxin family, is believed to be one of its virulence factors and to have an important role in the bacterium's pathogenicity. This toxin selectively kills human leukocytes by inducing apoptosis and lysis. Here, we report that leukotoxin-induced cell death of macrophages proceeded through a process that differs from the classical characteristics of apoptosis and necrosis. A. actinomycetemcomitans leukotoxin-induced several cellular and molecular mechanisms in human macrophages that led to a specific and excessive pro-inflammatory response with particular secretion of both interleukin (IL)-1β and IL-18. In addition, this pro-inflammatory cell death was inhibited by oxidized ATP, which indicates involvement of the purinergic receptor P2X(7) in this process. This novel virulence mechanism of the leukotoxin may have an important role in the pathogenic potential of this bacterium and can be a target for future therapeutic agents.
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Affiliation(s)
- P Kelk
- Division of Molecular Periodontology, Department of Odontology, Faculty of Medicine, Umeå University, Umeå, Sweden.
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Elamin A, Albandar JM, Poulsen K, Ali RW, Bakken V. Prevalence of Aggregatibacter actinomycetemcomitans in Sudanese patients with aggressive periodontitis: a case-control study. J Periodontal Res 2011; 46:285-91. [DOI: 10.1111/j.1600-0765.2010.01337.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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17
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Claesson R, Lagervall M, Höglund-Aberg C, Johansson A, Haubek D. Detection of the highly leucotoxic JP2 clone of Aggregatibacter actinomycetemcomitans in members of a Caucasian family living in Sweden. J Clin Periodontol 2010; 38:115-21. [DOI: 10.1111/j.1600-051x.2010.01643.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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HAUBEK DORTE. The highly leukotoxic JP2 clone of Aggregatibacter actinomycetemcomitans: evolutionary aspects, epidemiology and etiological role in aggressive periodontitis. APMIS 2010:1-53. [DOI: 10.1111/j.1600-0463.2010.02665.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Kuboniwa M, Inaba H, Amano A. Genotyping to distinguish microbial pathogenicity in periodontitis. Periodontol 2000 2010; 54:136-59. [DOI: 10.1111/j.1600-0757.2010.00352.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Fumarulo R, Cassano A, Mariggiò MA. Exogenous factors in the immunotoxicity of oral PMN. Immunopharmacol Immunotoxicol 2010; 33:1-10. [PMID: 20373855 DOI: 10.3109/08923971003762782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Current evidence indicates that periodontal disease is frequently due to inappropriate levels of gingival granulocyte functions. Reason of this failure may be the toxic effects of a number of local or systemic exogenous factors, capable of spreading through the gingival crevice environment, and strongly conditioning the granulocyte activities. The wide list includes bacteria and granulotoxic products, hedonistic drugs (mainly tobacco), and chemotherapeutic agents (especially antimicrobials used for preventing or reducing the accumulation of dental plaque). Almost always, their presence induces a time- and/or dose-dependent toxicity.
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Affiliation(s)
- Ruggiero Fumarulo
- Department of Biomedical Sciences and Human Oncology, University of Bari Medical School, Bari, Italy.
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Haubek D, Ennibi OK, Væth M, Poulsen S, Poulsen K. Stability of the JP2 Clone of Aggregatibacter actinomycetemcomitans. J Dent Res 2009; 88:856-60. [DOI: 10.1177/0022034509342190] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The JP2 clone of Aggregatibacter actinomycetemcomitans is strongly associated with aggressive periodontitis. To obtain information about colonization dynamics of the JP2 clone, we used PCR to examine its presence in 365 Moroccan juveniles from whom periodontal plaque samples were collected at baseline and after one and two years. Periodontal attachment loss was measured at baseline and at the two-year follow-up. At baseline, 43 (12%) carriers of the JP2 clone were found. Nearly half (44 %) of these were persistently colonized with the clone. The relative risk for the development of aggressive periodontitis, adjusted for the concomitant presence of other genotypes of A. actinomycetemcomitans, was highest for individuals continuously infected by the JP2 clone (RR = 13.9; 95% CI, 9.0 to 21.4), indicating a relationship between infectious dose and disease, which further substantiates the evidence for the JP2 clone as a causal factor in aggressive periodontitis.
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Affiliation(s)
- D. Haubek
- Department of Pediatric Dentistry, School of Dentistry, Vennelyst Boulevard 9, DK-8000 Aarhus C,
- Department of Medical Microbiology and Immunology, Wilhelm Meyers Allé, DK-8000 Aarhus C, and
- Department of Biostatistics, Vennelyst Boulevard 6, DK-8000 Aarhus C, Faculty of Health Sciences, University of Aarhus, Aarhus, Denmark; and
- Department of Periodontology, Dental Faculty, University of Rabat, BP 6212 Les Institutes Rabat, Morocco
| | - O.-K. Ennibi
- Department of Pediatric Dentistry, School of Dentistry, Vennelyst Boulevard 9, DK-8000 Aarhus C,
- Department of Medical Microbiology and Immunology, Wilhelm Meyers Allé, DK-8000 Aarhus C, and
- Department of Biostatistics, Vennelyst Boulevard 6, DK-8000 Aarhus C, Faculty of Health Sciences, University of Aarhus, Aarhus, Denmark; and
- Department of Periodontology, Dental Faculty, University of Rabat, BP 6212 Les Institutes Rabat, Morocco
| | - M. Væth
- Department of Pediatric Dentistry, School of Dentistry, Vennelyst Boulevard 9, DK-8000 Aarhus C,
- Department of Medical Microbiology and Immunology, Wilhelm Meyers Allé, DK-8000 Aarhus C, and
- Department of Biostatistics, Vennelyst Boulevard 6, DK-8000 Aarhus C, Faculty of Health Sciences, University of Aarhus, Aarhus, Denmark; and
- Department of Periodontology, Dental Faculty, University of Rabat, BP 6212 Les Institutes Rabat, Morocco
| | - S. Poulsen
- Department of Pediatric Dentistry, School of Dentistry, Vennelyst Boulevard 9, DK-8000 Aarhus C,
- Department of Medical Microbiology and Immunology, Wilhelm Meyers Allé, DK-8000 Aarhus C, and
- Department of Biostatistics, Vennelyst Boulevard 6, DK-8000 Aarhus C, Faculty of Health Sciences, University of Aarhus, Aarhus, Denmark; and
- Department of Periodontology, Dental Faculty, University of Rabat, BP 6212 Les Institutes Rabat, Morocco
| | - K. Poulsen
- Department of Pediatric Dentistry, School of Dentistry, Vennelyst Boulevard 9, DK-8000 Aarhus C,
- Department of Medical Microbiology and Immunology, Wilhelm Meyers Allé, DK-8000 Aarhus C, and
- Department of Biostatistics, Vennelyst Boulevard 6, DK-8000 Aarhus C, Faculty of Health Sciences, University of Aarhus, Aarhus, Denmark; and
- Department of Periodontology, Dental Faculty, University of Rabat, BP 6212 Les Institutes Rabat, Morocco
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Kimizuka R, Kato T, Hashimoto S, Yamanaka-Okada A, Okuda K, Ishihara K. Congo Red-binding Protein in Rough-phenotype Aggregatibacter actinomycetemcomitans is Amyloid-like Fiber. THE BULLETIN OF TOKYO DENTAL COLLEGE 2009; 50:23-9. [DOI: 10.2209/tdcpublication.50.23] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Handfield M, Baker HV, Lamont RJ. Beyond good and evil in the oral cavity: insights into host-microbe relationships derived from transcriptional profiling of gingival cells. J Dent Res 2008; 87:203-23. [PMID: 18296603 DOI: 10.1177/154405910808700302] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In many instances, the encounter between host and microbial cells, through a long-standing evolutionary association, can be a balanced interaction whereby both cell types co-exist and inflict a minimal degree of harm on each other. In the oral cavity, despite the presence of large numbers of diverse organisms, health is the most frequent status. Disease will ensue only when the host-microbe balance is disrupted on a cellular and molecular level. With the advent of microarrays, it is now possible to monitor the responses of host cells to bacterial challenge on a global scale. However, microarray data are known to be inherently noisy, which is caused in part by their great sensitivity. Hence, we will address several important general considerations required to maximize the significance of microarray analysis in depicting relevant host-microbe interactions faithfully. Several advantages and limitations of microarray analysis that may have a direct impact on the significance of array data are highlighted and discussed. Further, this review revisits and contextualizes recent transcriptional profiles that were originally generated for the specific study of intricate cellular interactions between gingival cells and 4 important plaque micro-organisms. To our knowledge, this is the first report that systematically investigates the cellular responses of a cell line to challenge by 4 different micro-organisms. Of particular relevance to the oral cavity, the model bacteria span the entire spectrum of documented pathogenic potential, from commensal to opportunistic to overtly pathogenic. These studies provide a molecular basis for the complex and dynamic interaction between the oral microflora and its host, which may lead, ultimately, to the development of novel, rational, and practical therapeutic, prophylactic, and diagnostic applications.
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Affiliation(s)
- M Handfield
- Department of Oral Biology, College of Dentistry, Box 100424 JHMHSC, University of Florida, Gainesville, FL 32610-0424, USA.
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Haubek D, Ennibi OK, Poulsen K, Vaeth M, Poulsen S, Kilian M. Risk of aggressive periodontitis in adolescent carriers of the JP2 clone of Aggregatibacter (Actinobacillus) actinomycetemcomitans in Morocco: a prospective longitudinal cohort study. Lancet 2008; 371:237-42. [PMID: 18207019 DOI: 10.1016/s0140-6736(08)60135-x] [Citation(s) in RCA: 261] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND Periodontitis is a loss of supporting connective tissue and alveolar bone around teeth, and if it occurs in an aggressive form it can lead to tooth loss before the age of 20 years. Although the cause of periodontitis in general remains elusive, a particular clone (JP2) of the gram-negative rod Aggregatibacter (Actinobacillus) actinomycetemcomitans is considered a possible aetiological agent of the aggressive form in adolescents living in or originating from north and west Africa, where the disease is highly prevalent. We did a population-based longitudinal study of adolescents to assess the role of the JP2 clone in the initiation of aggressive periodontitis. METHODS A total of 700 adolescents from public schools in Rabat, Morocco, were enrolled in the study. We used PCR to detect A actinomycetemcomitans in plaque samples (taken from molar and incisor sites) and to differentiate between the JP2 clone and other non-JP2 genotypes of the bacterium. 18 individuals were found to already have periodontitis and were excluded. The 682 periodontally healthy adolescents (mean age 12.5 years; SD 1.0) were classified according to their A actinomycetemcomitans carrier status at baseline. After 2 years, 428 (62.8%) individuals returned for re-examination, which included recording of periodontal attachment loss measured from the cemento-enamel junction to the bottom of the periodontal pockets of all teeth present. FINDINGS Individuals who carried the JP2 clone of A actinomycetemcomitans alone (relative risk 18.0; 95% CI 7.8-41.2, p<0.0001) or together with non-JP2 clones of A actinomycetemcomitans (12.4; 5.2-29.9, p<0.0001) had a significantly increased risk of periodontal attachment loss. A much less pronounced disease risk was found in those carrying non-JP2 clones only (3.0; 1.3-7.1, p=0.012). INTERPRETATION The JP2 clone of A actinomycetemcomitans is likely to be an important aetiological agent in initiation of periodontal attachment loss in children and adolescents. Co-occurrence of non-JP2 clones of A actinomycetemcomitans reduces the risk of development of periodontitis, suggesting competition for the ecological niche between the JP2 and non-JP2 clones of this species.
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Affiliation(s)
- Dorte Haubek
- Department of Community Oral Health and Pediatric Dentistry, University of Aarhus, Denmark.
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25
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Affiliation(s)
- Denis F Kinane
- Center for Oral Health and Systemic Disease, University of Louisville School of Dentistry, Louisville, KY, USA
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Kelk P, Claesson R, Chen C, Sjöstedt A, Johansson A. IL-1beta secretion induced by Aggregatibacter (Actinobacillus) actinomycetemcomitans is mainly caused by the leukotoxin. Int J Med Microbiol 2007; 298:529-41. [PMID: 17888725 DOI: 10.1016/j.ijmm.2007.06.005] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Revised: 05/25/2007] [Accepted: 06/05/2007] [Indexed: 12/01/2022] Open
Abstract
Aggregatibacter (Actinobacillus) actinomycetemcomitans forms a leukotoxin that selectively lyses primate neutrophils, monocytes and triggers apoptosis in promyeloic cells and degranulation of human neutrophils. Recently, we showed that the leukotoxin causes activation of caspase-1 and abundant secretion of bio-active IL-1beta from human macrophages. In this study, we show that high levels of IL-beta correlated with a high proportion of A. actinomycetemcomitans in clinical samples from a patient with aggressive periodontitis. To determine the relative contribution of leukotoxin to the overall bacteria-induced IL-1beta secretion, macrophages were isolated from peripheral blood and exposed to different concentrations of live A. actinomycetemcomitans strains with either no, low or high production of leukotoxin. Cell lysis and levels of IL-1beta, IL-6, TNF-alpha and caspase-1 were measured by ELISA and flow cytometry. Leukotoxin was the predominant cause of IL-1beta secretion from macrophages, even in the A. actinomycetemcomitans strain with low leukotoxin production. Macrophages exposed to non-leukotoxic bacteria accumulated cytosolic pro-IL-1beta, which was secreted by a secondary exposure to leukotoxic bacteria. In conclusion, the present study shows for the first time that A. actinomycetemcomitans-induced IL-1beta secretion from human macrophages in vitro is mainly caused by leukotoxin.
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Affiliation(s)
- Peyman Kelk
- Division of Periodontology, Department of Odontology, Faculty of Medicine, Umeå University, SE-901 85 Umeå, Sweden.
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Wu YM, Yan J, Chen LL, Gu ZY. Association between infection of different strains of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in subgingival plaque and clinical parameters in chronic periodontitis. J Zhejiang Univ Sci B 2007; 8:121-31. [PMID: 17266188 PMCID: PMC1791058 DOI: 10.1631/jzus.2007.b0121] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The aim of this study was to investigate subgingival infection frequencies of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans strains with genetic variation in Chinese chronic periodontitis (CP) patients and to evaluate its correlation with clinical parameters. METHODS Two multiplex polymerase chain reaction (PCR) assays were developed to detect the 16SrDNA, collagenase (prtC) and fimbria (fimA) genes of P. gingivalis and the 16SrDNA, leukotoxin (lktA) and fimbria-associated protein (fap) genes of A. actinomycetemcomitans in 60 sulcus samples from 30 periodontal healthy subjects and in 122 subgingival plaque samples from 61 patients with CP. The PCR products were further T-A cloned and sent for nucleotide sequence analysis. RESULTS The 16SrDNA, prtC and fimA genes of P. gingivalis were detected in 92.6%, 85.2% and 80.3% of the subgingival plaque samples respectively, while the 16SrDNA, lktA and fap genes of A. actinomycetemcomitans were in 84.4%, 75.4% and 50.0% respectively. Nucleotide sequence analysis showed 98.62%~100% homology of the PCR products in these genes with the reported sequences. P. gingivalis strains with prtC+/fimA+ and A. actinomycetemcomitans with lktA+ were predominant in deep pockets (>6 mm) or in sites with attachment loss > or =5 mm than in shallow pockets (3~4 mm) or in sites with attachment loss < or =2 mm (P<0.05). P. gingivalis strains with prtC+/fimA+ also showed higher frequency in gingival index (GI)=3 than in GI=1 group (P<0.05). CONCLUSION Infection of P. gingivalis with prtC+/fimA+ and A. actinomycetemcomitans with lktA+ correlates with periodontal destruction of CP in Chinese. Nonetheless P. gingivalis fimA, prtC genes and A. actinomycetemcomitans lktA gene are closely associated with periodontal destruction, while A. actinomycetemcomitans fap gene is not.
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Affiliation(s)
- Yan-min Wu
- Department of Stomatology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
| | - Jie Yan
- Department of Medical Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou 310006, China
| | - Li-li Chen
- Department of Stomatology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
- †E-mail:
| | - Zhi-yuan Gu
- Department of Oral and Maxillofacial Surgery, the Affiliated Hospital of Stomatology, School of Medicine, Zhejiang University, Hangzhou 310003, China
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Haubek D, Poulsen K, Kilian M. Microevolution and patterns of dissemination of the JP2 clone of Aggregatibacter (Actinobacillus) actinomycetemcomitans. Infect Immun 2007; 75:3080-8. [PMID: 17353281 PMCID: PMC1932881 DOI: 10.1128/iai.01734-06] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The natural history, microevolution, and patterns of interindividual transmission and global dissemination of the JP2 clone of Aggregatibacter (Actinobacillus) actinomycetemcomitans were studied by population genetic analysis. The JP2 clone is strongly associated with aggressive periodontitis in adolescents of African descent and differs from other clones of the species by several genetic peculiarities, including a 530-bp deletion in the promoter region of the leukotoxin gene operon, which results in increased leukotoxic activity. Multilocus sequence analysis of 82 A. actinomycetemcomitans strains, 66 of which were JP2 clone strains collected over a period of more than 20 years, confirmed that there is a clonal population structure with evolutionary lineages corresponding to serotypes. Although genetically highly conserved, as shown by alignment of sequences of eight housekeeping genes, strains belonging to the JP2 clone had a number of point mutations, particularly in the pseudogenes hbpA and tbpA. Characteristic mutations allowed isolates from individuals from the Mediterranean area and from West Africa, including the Cape Verde Islands, to be distinguished. The patterns of mutations indicate that the JP2 clone initially emerged as a distinct genotype in the Mediterranean part of Africa approximately 2,400 years ago and subsequently spread to West Africa, from which it was transferred to the American continents during the transatlantic slave trade. The sustained exclusive colonization of individuals of African descent despite geographical separation for centuries suggests that the JP2 clone has a distinct host tropism. The colonization of family members by JP2 clone strains with unique point mutations provides strong evidence that there is intrafamilial transmission and suggests that dissemination of the JP2 clone is restricted to close contacts.
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Affiliation(s)
- Dorte Haubek
- Department of Community Oral Health and Pediatric Dentistry, School of Dentistry, Faculty of Health Science, University of Aarhus, Vennelyst Boulevard 9, DK-8000 Aarhus C, Denmark.
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Kilian M, Frandsen EVG, Haubek D, Poulsen K. The etiology of periodontal disease revisited by population genetic analysis. Periodontol 2000 2006; 42:158-79. [PMID: 16930310 DOI: 10.1111/j.1600-0757.2006.00159.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Mogens Kilian
- Department of Bacteriology, Institute of Medical Microbiology and Immunology, University of Aarhus, Aarhus, Denmark
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Haubek D, Havemose-Poulsen A, Westergaard J. Aggressive periodontitis in a 16-year-old Ghanaian adolescent, the original source of Actinobacillus actinomycetemcomitans strain HK1651 - a 10-year follow up. Int J Paediatr Dent 2006; 16:370-5. [PMID: 16879336 DOI: 10.1111/j.1365-263x.2006.00735.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The highly leukotoxic JP2 clone of Actinobacillus actinomycetemcomitans is strongly associated with periodontitis in adolescents. Availability of the DNA sequence of the complete genome of A. actinomycetemcomitans strain HK1651, a representative strain of the JP2 clone (http://www.genome.ou.edu/act.html), has provided new possibilities in basic research regarding the understanding of the pathogenesis of A. actinomycetemcomitans in periodontitis. This case report describes the periodontal treatment of the original source of A. actinomycetemcomitans HK1651, a 16-year-old Ghanaian adolescent girl with aggressive periodontitis. The bacterial examination involved polymerase chain reaction analysis for presence of JP2 and non-JP2 types of A. actinomycetemcomitans. The treatment, including periodontal surgery supplemented by antibiotics, arrested the progression of periodontitis for more than 10 years. Initially, infection by A. actinomycetemcomitans, including the JP2 clone, was detected at various locations in the oral cavity and was not limited to the periodontal pockets. Post-therapy, the JP2 clone of A. actinomycetemcomitans disappeared, while the non-JP2 types of A. actinomycetemcomitans remained a part of the oral microflora.
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Affiliation(s)
- D Haubek
- Department of Community Oral Health and Pediatric Dentistry, School of Dentistry University of Aarhus, Denmark.
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Haubek D, Ismaili Z, Poulsen S, Ennibi OK, Benzarti N, Baelum V. Association between sharing of toothbrushes, eating and drinking habits and the presence of Actinobacillus actinomycetemcomitans in Moroccan adolescents. ACTA ACUST UNITED AC 2005; 20:195-8. [PMID: 15943761 DOI: 10.1111/j.1399-302x.2005.00210.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND/AIMS Actinobacillus actinomycetemcomitans is frequently detected in dental plaque collected from Moroccan adolescents, and has been shown to be associated with clinical attachment loss in this population. The aim of this study was to assess whether behaviors such as the sharing of toothbrushes, and eating and drinking habits were associated with the presence of A. actinomycetemcomitans in Moroccan adolescents. MATERIALS AND METHODS A total of 121 adolescents were clinically examined. Interviews regarding sharing of toothbrushes, eating and drinking habits were performed, and plaque samples were collected and analyzed for A. actinomycetemcomitans with different leukotoxin promoter types by polymerase chain reaction. Based on eating and drinking habits, the study population was divided in a low risk behavior group (LRB) and a high risk behavior group (HRB). RESULTS No association was found between the sharing of toothbrushes and the presence of A. actinomycetemcomitans. The odds ratios between the HRB and LRB group for being positive for the JP2 type, for non-JP2 types, and for any type of A. actinomycetemcomitans were 4.74 (95% CI 0.55; 40.71), 2.49 (95% CI 1.03; 5.97), and 2.97 (95% CI 1.28; 6.91), respectively. The difference in the mean number of teeth with a clinical attachment loss of > or = 3 mm between the HRB and the LRB group was 0.91(95% CI 0.09; 1.72). CONCLUSION Sharing of toothbrushes does not seem to be associated with the presence of A. actinomycetemcomitans in young Moroccans. Eating and drinking habits conducive to exchange of saliva are positively associated with presence of A. actinomycetemcomitans, and with a higher level of clinical attachment loss.
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Affiliation(s)
- D Haubek
- Department of Community Oral Health and Pediatric Dentistry, School of Dentistry, Faculty of Health Sciences, University of Aarhus, Denmark.
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Leung WK, Ngai VKS, Yau JYY, Cheung BPK, Tsang PWK, Corbet EF. Characterization of Actinobacillus actinomycetemcomitans isolated from young Chinese aggressive periodontitis patients. J Periodontal Res 2005; 40:258-68. [PMID: 15853973 DOI: 10.1111/j.1600-0765.2005.00805.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE This study characterized Actinobacillus actinomycetemcomitans isolates from young Chinese aggressive periodontitis patients. METHODS Subgingival plaque samples (two/subject) were collected from diseased subjects < 25 years old (n = 9, mean age 21.1 +/- 1.6 years) and age-matched periodontitis-free controls (n = 47, mean age 22.0 +/- 1.1 years). Selective and anaerobic culture were used. The serotype, leukotoxin gene (ltx) operon promoter and the cytolethal distending toxin (cdt) genes complex of the A. actinomycetemcomitans isolates were investigated. Effects of the isolates on non-keratinizing periodontal ligament epithelial cells monolayer were studied. RESULTS Diseased subjects had significantly higher full-mouth bleeding score (p = 0.002) and total viable counts from plaque samples (7.2 x 10(6) vs. 2.1 x 10(5) CFU/paperpoint, p < 0.005). A. actinomycetemcomitans was isolated from 67%/56% or 6%/4% of diseased or controls subject/sites, respectively (p < 0.001). The proportion of A. actinomycetemcomitans isolatable from aggressive periodontitis or periodontitis-free associated subgingival plaque was low (0.7% vs. 0.1%, p < 0.02). The serotype of the isolates was characterized. All isolates possessed 652-like ltx gene promoter and all but one serotype c isolate from a diseased patient had intact cdtABC genes. That particular strain appeared to confer the least cellular damages on periodontal ligament epithelial monolayer compared to others. CONCLUSION This preliminary study confirmed the notion of increased prevalence and quantity of A. actinomycetemcomitans associated with aggressive periodontitis in young patients. The overall ltx promoter and cdt characteristics of the A. actinomycetemcomitans isolates, however, were similar among the diseased and control groups. A strain lacking the cdtABC gene appeared to be less damaging to a periodontal ligament epithelial cell model. Further studies therefore are warranted to clarify the pathogenic role and potentials of A. actinomycetemcomitans in aggressive periodontitis.
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Affiliation(s)
- W Keung Leung
- Faculty of Dentistry, Prince Philip Dental Hospital, The University of Hong Kong, Hong Kong SAR, China.
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Belibasakis GN, Johansson A, Wang Y, Chen C, Kalfas S, Lerner UH. The cytolethal distending toxin induces receptor activator of NF-kappaB ligand expression in human gingival fibroblasts and periodontal ligament cells. Infect Immun 2005; 73:342-51. [PMID: 15618171 PMCID: PMC538937 DOI: 10.1128/iai.73.1.342-351.2005] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Actinobacillus actinomycetemcomitans is associated with localized aggressive periodontitis, a disease characterized by rapid loss of the alveolar bone surrounding the teeth. Receptor activator of NF-kappaB Ligand (RANKL) and osteoprotegerin (OPG) are two molecules that regulate osteoclast formation and bone resorption. RANKL induces osteoclast differentiation and activation, whereas OPG blocks this process by acting as a decoy receptor for RANKL. The purpose of this study was to investigate the effect of A. actinomycetemcomitans on the expression of RANKL and OPG in human gingival fibroblasts and periodontal ligament cells. RANKL mRNA expression was induced in both cell types challenged by A. actinomycetemcomitans extract, whereas OPG mRNA expression remained unaffected. Cell surface RANKL protein was also induced by A. actinomycetemcomitans, whereas there was no change in OPG protein secretion. A cytolethal distending toxin (Cdt) gene-knockout strain of A. actinomycetemcomitans did not induce RANKL expression, in contrast to its wild-type strain. Purified Cdt from Haemophilus ducreyi alone, or in combination with extract from the A. actinomycetemcomitans cdt mutant strain, induced RANKL expression. Pretreatment of A. actinomycetemcomitans wild-type extract with Cdt antiserum abolished RANKL expression. In conclusion, A. actinomycetemcomitans induces RANKL expression in periodontal connective tissue cells. Cdt is crucial for this induction and may therefore be involved in the pathological bone resorption during the process of localized aggressive periodontitis.
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Affiliation(s)
- G N Belibasakis
- Divisions of Oral Microbiology and Oral Cell Biology, Department of Odontology, Umeå University, S-901 87 Umeå, Sweden.
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Kelk P, Claesson R, Hänström L, Lerner UH, Kalfas S, Johansson A. Abundant secretion of bioactive interleukin-1beta by human macrophages induced by Actinobacillus actinomycetemcomitans leukotoxin. Infect Immun 2005; 73:453-8. [PMID: 15618184 PMCID: PMC538939 DOI: 10.1128/iai.73.1.453-458.2005] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Actinobacillus actinomycetemcomitans produces a leukotoxin that selectively kills human leukocytes. Recently, we reported that macrophages are highly sensitive to leukotoxin and that their lysis involves activation of caspase 1. In this study, we show that leukotoxin also induces the production and release of proinflammatory cytokines from human macrophages. The macrophages were challenged with leukotoxin or lipopolysaccharide (LPS) from A. actinomycetemcomitans or LPS from Escherichia coli, and the production and secretion of interleukin-1beta (IL-1beta), IL-6, and tumor necrosis factor alpha (TNF-alpha) were determined at the mRNA and protein levels by reverse transcription-PCR and enzyme-linked immunosorbent assay, respectively. Leukotoxin (1 to 30 ng/ml) induced abundant production and secretion of IL-1beta, while the effects on IL-6 and TNF-alpha production were limited. Leukotoxin (1 ng/ml) caused a 10-times-higher release of IL-1beta than did LPS (100 ng/ml). The secreted IL-1beta was mainly the bioactive 17-kDa protein. At higher concentrations (>30 ng/ml), leukotoxin caused secretion of mainly inactive cytokine, the 31-kDa pro-IL-1beta. The presence of specific antibodies to IL-1beta or of a caspase 1 inhibitor blocked the secretion and production of the cytokine. Supernatants of leukotoxin-challenged macrophages stimulated bone resorption when tested in a mouse calvarial model. The activity could be blocked by an IL-1 receptor antagonist or specific antibodies to IL-1beta. We concluded that A. actinomycetemcomitans leukotoxin can trigger abundant production and secretion of bioactive IL-1beta by human macrophages, which is mediated by activation of caspase 1.
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Affiliation(s)
- P Kelk
- Department of Odontology, University of Umeå, S-901 87 Umeå, Sweden
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Abstract
Although polymicrobial diseases are not a new concept for microbiologists, they are experiencing a resurgence of interest owing to the development of suitable animal models and new molecular techniques that allow these diseases to be studied effectively. This broad review provides an excellent introduction to this fascinating topic. Examples are included of each type of polymicrobial disease and the animal models that are used to study these diseases are discussed. In many instances, schematics for the animal model are presented. Viral co-infections including bovine viral diarrhoeal viruses, porcine reproductive and respiratory syndrome, mixed hepatitis virus infections and HIV co-infection with hepatitis virus are discussed, together with attempts to model these diseases in animals. Viral and bacterial co-infections are reviewed with a special focus on otitis media and the rodent models that have been used to probe this important childhood illness. Of the polybacterial diseases, periodontitis is one of the best understood and a clinically relevant rodent model is now available. This model, and the role of biofilm formation in periodontitis are examined. Fungal infections of humans are often referred to as 'opportunistic' but in fact these infections are often fungal co-infections with viruses such as HIV and fungal mixed co-infections. The roles of these infections in disease and the rodent models used to study them are discussed. Parasite co-infections are thought to have a role in the severity of malaria and the severity of Lyme arthritis. These diseases and attempts to model them are evaluated. Finally, co-infections that are associated with virus-induced immunosuppression are discussed, together with their animal models.
Polymicrobial diseases involve two or more microorganisms that act synergistically, or in succession, to mediate complex disease processes. Although polymicrobial diseases in animals and humans can be caused by similar organisms, these diseases are often also caused by organisms from different kingdoms, genera, species, strains, substrains and even by phenotypic variants of a single species. Animal models are often required to understand the mechanisms of pathogenesis, and to develop therapies and prevention regimes. However, reproducing polymicrobial diseases of humans in animal hosts presents significant challenges.
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Affiliation(s)
- Lauren O Bakaletz
- Center for Microbial Pathogenesis, Columbus Children's Research Institute, Department of Pediatrics, The Ohio State University College of Medicine & Public Health, 700 Children's Drive, Columbus, Ohio 43205-2696, USA.
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Kolodrubetz D, Phillips L, Jacobs C, Burgum A, Kraig E. Anaerobic regulation of Actinobacillus actinomycetemcomitans leukotoxin transcription is ArcA/FnrA-independent and requires a novel promoter element. Res Microbiol 2004; 154:645-53. [PMID: 14596902 DOI: 10.1016/j.resmic.2003.09.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The periodontal pathogen, Actinobacillus actinomycetemcomitans, produces a 116-kDa leukotoxin that appears to help the bacterium evade the innate host immune response. The expression of leukotoxin is induced when cells are grown anaerobically, a condition found in the subgingival crevice. This regulation most likely occurs at the transcriptional stage since the levels of leukotoxin RNA are induced by hypoxic growth. In order to map the leukotoxin promoter element(s) responsible for oxygen regulation, deletion and linker-scanning mutations were cloned into a transcriptional reporter gene plasmid and then tested in A. actinomycetemcomitans grown aerobically or anaerobically. A 35-bp DNA element, at position -36 to -70, was found to be responsible for the repression of leukotoxin synthesis in aerobically grown A. actinomycetemcomitans. The sequence of this oxygen response element (ORE) does not match the consensus binding sites for known DNA binding proteins, not even Fnr or ArcA which play major roles in oxygen regulation in other bacteria. However, since sequence analysis alone cannot disprove a role for the Fnr or ArcAB pathways in leukotoxin regulation, the genes for the Fnr and ArcA homologues in A. actinomycetemcomitans were identified, mutated by targeted insertional mutagenesis and assessed for loss of oxygen regulation. Deletion of either fnr or arcA altered the expression of numerous A. actinomycetemcomitans proteins, but leukotoxin expression was still repressed by oxygen. These results, coupled with the promoter mutation analyses, lead to the conclusion that A. actinomycetemcomitans employs a novel pathway in the aerobic/anaerobic regulation of leukotoxin synthesis.
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Affiliation(s)
- David Kolodrubetz
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229-3900, USA.
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Haubek D, Westergaard J. Detection of a highly toxic clone of Actinobacillus actinomycetemcomitans (JP2) in a Moroccan immigrant family with multiple cases of localized aggressive periodontitis. Int J Paediatr Dent 2004; 14:41-8. [PMID: 14706027 DOI: 10.1111/j.1365-263x.2004.00518.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The JP2 clone of Actinobacillus actinomycetemcomitans, a high-leukotoxin-producing strain, characterized by a 530-basepair (bp) deletion in the promoter region of the leukotoxin gene operon and mainly found among individuals with African origin, is associated with localized aggressive periodontitis. The objective of the study was to examine the occurrence of periodontal disease in a Moroccan immigrant family living in Denmark in which the oldest son (14 year) was referred and treated for localized aggressive periodontitis. Further, the potential occurrence of the JP2 clone of A. actinomycetemcomitans in the family was examined. Here we present the clinical, radiographic, and microbiological findings from the family. Clinical and radiographic examination of the other family members revealed that 3 of 5 younger siblings had localized aggressive periodontitis, one had gingivitis and the mother had chronic periodontitis. Despite scaling followed by intensive maintenance therapy several family members, including the sibling with gingivitis, had further attachment loss at the 1-year examination. The JP2 clone of A. actinomycetemcomitans was isolated from subgingival plaque samples from 4 children with periodontitis. In contrast, it was not detected in plaque from the oldest boy, who had been treated for localized aggressive periodontitis by surgery combined with antibiotic therapy. The 4 children with periodontitis and colonized with the JP2 clone were treated by scaling and antibiotic administration. One month later the JP2 clone could still be detected in plaque samples. In conclusion, it is confirmed that members of immigrant families with African origin are potential carriers of the JP2 clone and that those families often have multiple family members with localized aggressive periodontitis. It is proposed that those families are given periodontal examination frequently to benefit from early diagnosis and treatment of the disease.
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Affiliation(s)
- D Haubek
- Department of Community Oral Health and Pediatric Dentistry, University of Aarhus, Denmark.
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Mitchell C, Gao L, Demuth DR. Positive and negative cis-acting regulatory sequences control expression of leukotoxin in Actinobacillus actinomycetemcomitans 652. Infect Immun 2003; 71:5640-9. [PMID: 14500484 PMCID: PMC201044 DOI: 10.1128/iai.71.10.5640-5649.2003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Integration of IS1301 into an AT-rich inverted repeat located upstream of the ltx operon was previously shown to confer a hyperleukotoxic phenotype in Actinobacillus actinomycetemcomitans IS1 (T. He, T. Nishihara, D. R. Demuth, and I. Ishikawa, J. Periodontol. 70:1261-1268, 1999), but the mechanism leading to increased leukotoxin production was not determined. We show that an IS1 ltx promoter::lacZ reporter construct expresses 12-fold higher levels of beta-galactosidase activity than a reporter containing the ltx promoter from A. actinomycetemcomitans 652, suggesting that IS1301 increases transcription of the ltx operon. Examination of the IS1301 sequence identified a potential outwardly directed promoter. However, site-specific mutagenesis of the -35 element of the putative promoter had no effect on the transcriptional activity of the IS1 reporter construct. Furthermore, reverse transcriptase PCR and real-time PCR experiments did not detect a transcript that was initiated within IS1301. These results suggest that increased expression of leukotoxin in strain IS1 does not arise from an outwardly directed IS1301 promoter. To determine how IS1301 alters transcriptional regulation of the ltx operon, cis-acting sequences that regulate leukotoxin expression were identified. The AT-rich sequence that resides downstream from the site of IS1301 insertion was shown to function as a positive cis-acting regulator of leukotoxin expression. This sequence resembles an UP element in its location, AT-rich content, and activity and is homologous to the consensus UP element sequence. In addition, a negative cis-acting sequence was identified upstream from the site of IS1301 insertion, and deletion of this region increased promoter activity by fourfold. Mobility shift experiments showed that this region bound to a protein(s) in extracts from A. actinomycetemcomitans 652. The specific sequences required for this interaction were localized to a 26-nucleotide segment of the ltx promoter that resides 17 bp upstream from the site of IS1301 insertion. Together, these results suggest that positive and negative cis-acting sequences regulate leukotoxin expression and that IS1301 may increase transcription of the ltx operon in A. actinomycetemcomitans IS1 by displacing a negative cis-acting regulator approximately 900 bp upstream from the basal elements of the ltx promoter.
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Affiliation(s)
- Christine Mitchell
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19014, USA
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Fu Y, Korostoff JM, Fine DH, Wilson ME. Fc gamma receptor genes as risk markers for localized aggressive periodontitis in African-Americans. J Periodontol 2002; 73:517-23. [PMID: 12027254 DOI: 10.1902/jop.2002.73.5.517] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Receptors for the Fc fragment of immunoglobulin G (Fc gammaRs) play a crucial role in host defense against bacterial infection by linking humoral and cell-mediated immune responses. Allelic variants of certain Fc gammaRs have been shown to differ relative to their biologic activity. Thus, genes encoding allotypes with diminished activity have been suggested as potential risk factors for infectious diseases. The goal of this study was to determine whether specific Fc gammaRIIa, Fc gammaRIIIa, and Fc gammaRIIIb alleles and/or genotypes could be used to predict susceptibility to localized aggressive periodontitis (LAgP) in an African-American population. METHODS Whole blood or saliva was obtained from 48 LAgP and 67 periodontally-healthy African-American subjects. DNA was prepared from each sample. Fc gammaRIIa and Fc gammaRIIIa genotyping was analyzed by polymerase chain reaction (PCR) amplification of DNA with allele-specific primers followed by allele-specific restriction digestion of the products. Fc gammaRIIIb genotyping was done by allele-specific PCR. RESULTS There was a statistically significant over-representation of the Fc gammaRIIIb-NA2 allele in LAgP patients compared to controls (P = 0.024). Relative to the Fc gammaRIIIb-NA1/NA2 and homozygous NA1/NA1 genotypes, the prevalence of the Fc gammaRIIIb NA2/NA2 genotype was higher in the LAgP group relative to the control population. Individuals expressing this genotype appeared at greater risk for developing LAgP (odds ratio 2.271, 95% confidence interval: 1.005 to 5.132). There were no significant differences in the distribution of the Fc gammaRIIa H/R or Fc gammaRIIIa-158 F/V genotypes nor their allelic frequencies between the LAgP patients and controls. CONCLUSIONS These data suggest that the Fc gammaRIIIb NA2 allele and/or NA2/NA2 genotype may represent risk markers for susceptibility to LAgP in African-Americans.
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Affiliation(s)
- Yali Fu
- Dental Research Center, University of Medicine and Dentistry of New Jersey, Newark, USA
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Fong KP, Chung WO, Lamont RJ, Demuth DR. Intra- and interspecies regulation of gene expression by Actinobacillus actinomycetemcomitans LuxS. Infect Immun 2001; 69:7625-34. [PMID: 11705942 PMCID: PMC98856 DOI: 10.1128/iai.69.12.7625-7634.2001] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cell density-dependent control of gene expression is employed by many bacteria for regulating a variety of physiological functions, including the generation of bioluminescence, sporulation, formation of biofilms, and the expression of virulence factors. Although periodontal organisms do not appear to secrete acyl-homoserine lactone signals, several species, e.g., Porphyromonas gingivalis, Prevotella intermedia, and Fusobacterium nucleatum, have recently been shown to secrete a signal related to the autoinducer II (AI-2) of the signal system 2 pathway in Vibrio harveyi. Here, we report that the periodontal pathogen Actinobacillus actinomycetemcomitans expresses a homolog of V. harveyi luxS and secretes an AI-2-like signal. Cell-free conditioned medium from A. actinomycetemcomitans or from a recombinant Escherichia coli strain (E. coli AIS) expressing A. actinomycetemcomitans luxS induced luminescence in V. harveyi BB170 >200-fold over controls. AI-2 levels peaked in mid-exponential-phase cultures of A. actinomycetemcomitans and were significantly reduced in late-log- and stationary-phase cultures. Incubation of early-log-phase A. actinomycetemcomitans cells with conditioned medium from A. actinomycetemcomitans or from E. coli AIS resulted in a threefold induction of leukotoxic activity and a concomitant increase in leukotoxin polypeptide. In contrast, no increase in leukotoxin expression occurred when cells were exposed to sterile medium or to conditioned broth from E. coli AIS(-), a recombinant strain in which luxS was insertionally inactivated. A. actinomycetemcomitans AI-2 also induced expression of afuA, encoding a periplasmic iron transport protein, approximately eightfold, suggesting that LuxS-dependent signaling may play a role in the regulation of iron acquisition by A. actinomycetemcomitans. Finally, A. actinomycetemcomitans AI-2 added in trans complemented a luxS knockout mutation in P. gingivalis by modulating the expression of the luxS-regulated genes uvrB and hasF in this organism. Together, these results suggest that LuxS-dependent signaling may modulate aspects of virulence and the uptake of iron by A. actinomycetemcomitans and induce responses in other periodontal organisms in mixed-species oral biofilm.
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Affiliation(s)
- K P Fong
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia 19104-6002, USA
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Alpha CX, Guthmiller JM, Cummings HE, Schomberg LL, Noorani SM. Molecular analysis of Peptostreptococcus micros isolates from patients with periodontitis. J Periodontol 2001; 72:877-82. [PMID: 11495135 DOI: 10.1902/jop.2001.72.7.877] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Recent studies provide strong evidence implicating Peptostreptococcus micros in the pathogenesis of various oral infections, including oropharyngeal abscesses and periodontal disease. To date, very little is known regarding the role of P. micros in periodontal disease. Therefore, a genetic analysis was initiated to differentiate among strains of P. micros infecting periodontal patients. METHODS Sixty DNA samples of P. micros isolated from 15 patients with periodontal disease were evaluated. Arbitrarily primed polymerase chain reactions (AP-PCR) were performed using primer 3 (AGTCAGCCAC) and primer 13 (CAGCACCCAC). The PCR products were analyzed by gel electrophoresis. RESULTS The primers produced several unique patterns among the strains tested. Primer 3 resulted in 30 different patterns, whereas primer 13 resulted in 31 different patterns, which were distinct from those seen with primer 3. In 8 of 15 patients, the PCR profile was identical for all isolates cultured from that patient, indicating a clonal infection. In 4 of 15 patients, 2 different genotypes were identified. In the remaining 3 patients, all isolates cultured from these patients exhibited a unique genotype. CONCLUSIONS While P. micros appears to be heterogeneous throughout a population of periodontal patients, each patient is, for the most part, infected with a limited number of genotypes. These results demonstrate the genetic diversity of P. micros and the usefulness of AP-PCR for future epidemiological studies in understanding the role P. micros plays in periodontal disease pathogenesis.
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Affiliation(s)
- C X Alpha
- Dows Institute for Dental Research, College of Dentistry, University of Iowa, Iowa City 52242, USA
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