1
|
Raja M, Ummer F, Dhivakar CP. Aggregatibacter actinomycetemcomitans - a tooth killer? J Clin Diagn Res 2014; 8:ZE13-6. [PMID: 25302290 DOI: 10.7860/jcdr/2014/9845.4766] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 07/13/2014] [Indexed: 11/24/2022]
Abstract
Strong evidence is available on Aggregatibacter actinomycetemcomitans (A.a) on its role as the causative agent of localised juvenile periodontitis (LJP), a disease characterised by rapid destruction of the tooth-supporting tissues. This organism possesses a large number of virulence factors with a wide range of activities which enable it to colonise the oral cavity, invade periodontal tissues, evade host defences, initiate connective tissue destruction and interfere with tissue repair. Adhesion to epithelial and tooth surfaces is dependent on the presence of surface proteins and structures such as microvesicles and fimbriae. Invasion has been demonstrated in vivo and in vitro. The organism has a number of means of evading host defences which include: (i) production of leukotoxin; (ii) producing immunosuppressive factors; (iv) secreting proteases capable of cleaving IgG; and (v) producing Fc-binding.
Collapse
Affiliation(s)
- Manoj Raja
- Reader, Department of Periodontics, Karpaga Vinayaga Institute of Dental Sciences , Chennai, India
| | - Fajar Ummer
- Reader, Department of Periodontics, MES Dental College , Perintalmanna, India
| | - C P Dhivakar
- Senior Lecturer, Department of Periodontics, Karpagavinayaga Institute of Dental Sciences , Chennai, India
| |
Collapse
|
2
|
Nayab SN, Jones FH, Olsen I. Modulation of the human bone cell cycle by calcium ion-implantation of titanium. Biomaterials 2007; 28:38-44. [PMID: 16952393 DOI: 10.1016/j.biomaterials.2006.08.032] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Accepted: 08/16/2006] [Indexed: 11/18/2022]
Abstract
Ca ion implantation of Ti surfaces has previously been reported to enhances osseointegration in vivo. Although the mechanisms underlying the response of bone cells to these novel surfaces still remain unclear, it is possible that Ca ion-implanted Ti (Ca-Ti) may influence the growth of new bone by modulating the progression of the cell cycle. In the present study we have, therefore, examined the precise effects of Ca ion-implantation of Ti on the bone-like MG-63 cell line in vitro. The results of flow cytometry analysis showed that this surface markedly enhanced the proportion of cells which expressed Ki-67, a cell proliferation-associated nuclear antigen, compared with cells grown on the non-implanted Ti (control) surface. In addition, cultures grown on Ca-Ti and synchronized at the G1/S boundary by hydroxyurea more rapidly re-entered and progressed through the S and G2/M phases of the cell cycle than their counterparts on Ti. Ca ion-implantation also significantly increased the numbers of mitotic cells. These results thus show that alteration of the surface chemistry of Ti by high-energy implantation with Ca ion was able to substantially modulate the progression of the bone cell cycle, and suggest a possible means of enhancing the response of bone cells to implant materials.
Collapse
Affiliation(s)
- Saima N Nayab
- Division of Biomaterials and Tissue Engineering, University College London, Eastman Dental Institute, 256 Gray's Inn Road, London WC1X 8LD, UK
| | | | | |
Collapse
|
3
|
Mise K, Akifusa S, Watarai S, Ansai T, Nishihara T, Takehara T. Involvement of ganglioside GM3 in G(2)/M cell cycle arrest of human monocytic cells induced by Actinobacillus actinomycetemcomitans cytolethal distending toxin. Infect Immun 2005; 73:4846-52. [PMID: 16040998 PMCID: PMC1201191 DOI: 10.1128/iai.73.8.4846-4852.2005] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Actinobacillus actinomycetemcomitans produces a toxin called cytolethal distending toxin (CDT), which causes host cell DNA damage leading to the induction of DNA damage checkpoint pathways. CDT consists of three subunits, CdtA, CdtB, and CdtC. CdtB is the active subunit of CDT and exerts its effect as a nuclease that damages nuclear DNA, triggering cell cycle arrest. In the present study, we confirmed that the only combination of toxin proteins causing cell cycle arrest was that of all three recombinant CDT (rCDT) protein subunits. Furthermore, in order for rCDT to demonstrate toxicity, it was necessary for CdtA and CdtC to access the cell before CdtB. The coexistence of CdtA and CdtC was necessary for these subunits to bind to the cell. Cells treated with the glucosylceramide synthesis inhibitor 1-phenyl-2-palmitoylamino-3-morpholino-1-propanol showed resistance to the cytotoxicity induced by rCDT. Furthermore, LY-B cells, which are deficient in the biosynthesis of sphingolipid, also showed resistance to the cytotoxicity induced by rCDT. To evaluate the binding of each subunit for glucosylceramides, we performed thin-layer chromatography immunostaining. The results indicated that each subunit reacted with the glycosphingolipids GM1, GM2, GM3, Gb3, and Gb4. The rCDT mixture incubated with liposomes containing GM3 displayed partially reduced toxicity. These results indicate that GM3 can act as a CDT receptor.
Collapse
Affiliation(s)
- Koji Mise
- Department of Preventive Dentistry, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580, Japan
| | | | | | | | | | | |
Collapse
|
4
|
Henderson B, Nair SP, Ward JM, Wilson M. Molecular pathogenicity of the oral opportunistic pathogen Actinobacillus actinomycetemcomitans. Annu Rev Microbiol 2004; 57:29-55. [PMID: 14527274 DOI: 10.1146/annurev.micro.57.030502.090908] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Periodontitis is mankind's most common chronic inflammatory disease. One severe form of periodontitis is localized aggressive periodontitis (LAP), a condition to which individuals of African origin demonstrate an increased susceptibility. The main causative organism of this disease is Actinobacillus actinomycetemcomitans. A member of the Pasteurellaceae, A. actinomycetemcomitans produces a number of interesting putative virulence factors including (a) an RTX leukotoxin that targets only neutrophils and monocytes and whose action is influenced by a novel type IV secretion system involved in bacterial adhesion; (b) the newly discovered toxin, cytolethal distending toxin (CDT); and (c) a secreted chaperonin 60 with potent leukocyte-activating and bone resorbing activities. This organism also produces a plethora of proteins able to inhibit eukaryotic cell cycle progression and proteins and peptides that can induce distinct forms of proinflammatory cytokine networks. A range of other proteins interacting with the host is currently being uncovered. In addition to these secreted factors, A. actinomycetemcomitans is invasive with an unusual mechanism for entering, and traveling within, eukaryotic cells. This review focuses on recent advances in our understanding of the molecular and cellular pathogenicity of this fascinating oral bacterium.
Collapse
Affiliation(s)
- Brian Henderson
- Cellular Microbiology Research Group, Eastman Dental Institute, University College London, London WC1X 8LD, United Kingdom.
| | | | | | | |
Collapse
|
5
|
Tram U, Ferree PM, Sullivan W. Identification of Wolbachia--host interacting factors through cytological analysis. Microbes Infect 2003; 5:999-1011. [PMID: 12941392 DOI: 10.1016/s1286-4579(03)00192-8] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Manipulation of host reproduction and efficient maternal transmission have facilitated the global spread of Wolbachia through millions of insect species. Cytological studies of the most common Wolbachia-induced phenotype, cytoplasmic incompatibility (CI), demonstrate that Wolbachia induce CI by altering host cell cycle timing. Cytological analyses also suggest that microtubules and motor proteins may play a role in the maternal and somatic transmission of Wolbachia.
Collapse
Affiliation(s)
- Uyen Tram
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Cruz, CA 95064, USA.
| | | | | |
Collapse
|
6
|
Affiliation(s)
| | - Michael Wilson
- Cellular Microbiology Research Group and *Microbiology Department, Eastman Dental Institute, University College London and †Department of Biochemistry and Molecular Biology, University College London, London
| | | | - John M Ward
- Cellular Microbiology Research Group and *Microbiology Department, Eastman Dental Institute, University College London and †Department of Biochemistry and Molecular Biology, University College London, London
| |
Collapse
|
7
|
Belibasakis G, Johansson A, Wang Y, Claesson R, Chen C, Asikainen S, Kalfas S. Inhibited proliferation of human periodontal ligament cells and gingival fibroblasts by Actinobacillus actinomycetemcomitans: involvement of the cytolethal distending toxin. Eur J Oral Sci 2002; 110:366-73. [PMID: 12664467 DOI: 10.1034/j.1600-0722.2002.21350.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Actinobacillus actinomycetemcomitans can inhibit fibroblast proliferation. The objective of this study was to characterize the early proliferative responses of human periodontal ligament cells (PDLC) and gingival fibroblasts (GF) to A. actinomycetemcomitans components and to investigate the possible involvement of the cytolethal distending toxin (cdt) produced by this bacterium. The PDLC and GF were challenged with surface components of A. actinomycetemcomitans. Both DNA and protein synthesis as well as cell lysis or apoptosis were assayed for a 6-h period after addition of the bacterial extract. Unlike the controls, inhibition of DNA synthesis had already occurred in the challenged cells at the end of the initial 3- to 6-h period. No lysis or apoptosis was detected, and the total protein synthesis remained unaffected. The persistence of the effect on cell growth was confirmed after a 72-h period of challenge, during which the cells remained viable but exhibited an elongated and distended cell body. No significant differences were observed between PDLC and GF. When a cdt-knockout strain of A. actinomycetemcomitans was used almost no inhibitory effect on cell proliferation was observed. It was concluded that A. actinomycetemcomitans causes a non-lethal inhibition of proliferation in PDLC and GF as a result of an early arrest of DNA synthesis. Cytolethal distending toxin is responsible for most of this effect. This bacterial property may compromise tissue homeostasis in the periodontium.
Collapse
Affiliation(s)
- Georgios Belibasakis
- Division of Oral Microbiology, Institute for Odontology, Umeå University, S-90187 Umeå, Sweden.
| | | | | | | | | | | | | |
Collapse
|
8
|
Banks J, Poole S, Nair SP, Lewthwaite J, Tabona P, McNab R, Wilson M, Paul A, Henderson B. Streptococcus sanguis secretes CD14-binding proteins that stimulate cytokine synthesis: a clue to the pathogenesis of infective (bacterial) endocarditis? Microb Pathog 2002; 32:105-16. [PMID: 11855941 DOI: 10.1006/mpat.2001.0485] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Streptococcus sanguis is the major causative organism of infective (bacterial) endocarditis but, surprisingly, almost nothing is known about how it induces endocardial inflammation. In earlier studies we have shown that many bacteria secrete potent cytokine-inducing or -inhibiting proteins. We have therefore isolated the material secreted by S. sanguis grown on blood agar or in broth culture and have tested its ability to induce human peripheral blood monocytes to synthesize pro-inflammatory cytokines. The activation of monocytes by the secreted components of S. sanguis was almost totally blocked by heat and trypsin treatment but not by the lipopolysaccharide-inactivating antibiotic, polymyxin B, suggesting that activity is due to secreted proteins. The activity of the secreted material was significantly reduced by anti-CD14 monoclonal antibodies suggesting that the active protein (or proteins) was binding to the CD14/Toll-like receptor (TLR)4 complex. Fractionation of the secreted proteins by high performance liquid chromatography (HPLC) identified two proteins as being responsible for the majority of the cytokine induction: a manganese-dependent superoxide dismutase and a 190 kDa protein, which could not be sequenced, but which was neither CshA nor the PI/II proteins. These proteins, or the receptors to which they bind, may be therapeutic targets and may allow the development of adjunctive therapies to prevent endocardial damage during the often prolonged treatment of infective endocarditis with antibiotics. In addition, blocking of CD14 may have some therapeutic benefit.
Collapse
Affiliation(s)
- Julia Banks
- Cellular Microbiology Research Group, Eastman Dental Institute, University College London, 256 Gray's Inn Road, London, Hertfordshire, WC1X 8LD, U.K
| | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Akifusa S, Poole S, Lewthwaite J, Henderson B, Nair SP. Recombinant Actinobacillus actinomycetemcomitans cytolethal distending toxin proteins are required to interact to inhibit human cell cycle progression and to stimulate human leukocyte cytokine synthesis. Infect Immun 2001; 69:5925-30. [PMID: 11500475 PMCID: PMC98715 DOI: 10.1128/iai.69.9.5925-5930.2001] [Citation(s) in RCA: 72] [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
It has recently been discovered that Actinobacillus actinomycetemcomitans, an oral bacterium causing periodontitis, produces cytolethal distending toxin (CDT), a cell cycle-modulating toxin that has three protein subunits: CdtA, CdtB, and CdtC. In this study, we have cloned and expressed each toxin gene from A. actinomycetemcomitans in Escherichia coli and purified the recombinant Cdt proteins to homogeneity. Individual Cdt proteins failed to induce cell cycle arrest of the human epithelial cell line HEp-2. The only combinations of toxin proteins causing cell cycle arrest were the presence of all three Cdt proteins and the combination of CdtB and CdtC. A similar experimental protocol was used to determine if recombinant Cdt proteins were able to induce human peripheral blood mononuclear cells (PBMCs) to produce cytokines. The individual Cdt proteins were able to induce the synthesis by PBMCs of interleukin-1beta (IL-1beta), IL-6, and IL-8 but not of tumor necrosis factor alpha, IL-12, or granulocyte-macrophage colony-stimulating factor, with CdtC being the most potent and CdtB being the least potent cytokine inducer. There was evidence of synergism between these Cdt proteins in the stimulation of cytokine production, most markedly with gamma interferon, which required the minimum interaction of CdtB and -C to stimulate production.
Collapse
Affiliation(s)
- S Akifusa
- Cellular Microbiology Research Group, Eastman Dental Institute, University College London, London WC1X 8LD, United Kingdom
| | | | | | | | | |
Collapse
|
10
|
Henderson B, Tabona P, Poole S, Nair SP. Cloning and expression of the Actinobacillus actinomycetemcomitans thioredoxin (trx) gene and assessment of cytokine inhibitory activity. Infect Immun 2001; 69:154-8. [PMID: 11119501 PMCID: PMC97867 DOI: 10.1128/iai.69.1.154-158.2001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Thioredoxin is a ubiquitous redox control and cell stress protein. Unexpectedly, in recent years, thioredoxins have been found to exhibit both cytokine and chemokine activities, and there is increasing evidence that this class of protein plays a role in the pathogenesis of inflammatory diseases. In spite of this evidence, it has been reported that the oral bacterium and periodontopathogen Actinobacillus actinomycetemcomitans secretes an immunosuppressive factor (termed suppressive factor 1 [SF1] [T. Kurita-Ochiai and K. Ochiai, Infect. Immun. 64:50-54, 1996]) whose N-terminal sequence, we have determined, identifies it as thioredoxin. We have cloned and expressed the gene encoding the thioredoxin of A. actinomycetemcomitans and have purified the protein to homogeneity. The A. actinomycetemcomitans trx gene has 52 and 76% identities, respectively, to the trx genes of Escherichia coli and Haemophilus influenzae. Enzymatic analysis revealed that the recombinant protein had the expected redox activity. When the recombinant thioredoxin was tested for its capacity to inhibit the production of cytokines by human peripheral blood mononuclear cells, it showed no significant inhibitory capacity. We therefore conclude that the thioredoxin of A. actinomycetemcomitans does not act as an immunosuppressive factor, at least with human leukocytes in cultures, and that the identity of SF1 remains to be elucidated.
Collapse
Affiliation(s)
- B Henderson
- Cellular Microbiology Research Group, Eastman Dental Institute, University College London, London WC1X 8LD, United Kingdom.
| | | | | | | |
Collapse
|
11
|
Gadhavi A, Wilson M, Tabona P, Newman HN, Henderson B, Bennett JH. Inhibition of mitosis and induction of apoptosis in MG63 human osteosarcoma-derived cells in vitro by surface proteins from Actinobacillus actinomycetemcomintans. Arch Oral Biol 2000; 45:707-11. [PMID: 10869483 DOI: 10.1016/s0003-9969(00)00028-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Gentle saline extraction releases a heterogeneous mixture of proteins associated with the cell surface of Actinobacillus actinomycetemcomintans, termed the surface protein fraction (SF). Some SF components are biologically active and may modulate cell behaviour in a manner of putative importance in the aetiology of periodontitis. To further characterize this activity, the ability of the SF to induce mitosis and apoptosis in MG63 cells was investigated. Cells were plated at 10(3)-10(4) cells/cm(2) and allowed to attach before culture in the serum-free medium in the presence of 25 microg/ml SF for 2-24 h. The apoptotic and mitotic figures present were counted and the results expressed as an apoptotic or mitotic index. The apoptotic and mitotic compartments were very small, but there was an inverse correlation between mitosis and apoptosis. In control experiments the mitotic was higher than the apoptotic index, whilst in the presence of SF this was reversed. These results were confirmed using in situ end-labelling. SF, therefore, may stimulate apoptotic, but inhibit mitotic, activity in MG63 cells. This raises the possibility that components of SF might induce subtle changes in the balance between apoptosis and mitosis, which, in turn, could contribute to the progression of periodontitis.
Collapse
Affiliation(s)
- A Gadhavi
- Department of Periodontology, Eastman Dental Institute, University College London, 256 Grays Inn Road, WC1X 8LD, London, UK
| | | | | | | | | | | |
Collapse
|
12
|
Abstract
Actinobacillus species are Gram-negative bacteria responsible for several quite distinct disease conditions of animals. The natural habitat of the organisms is primarily the upper respiratory tract and oral cavity. A. lignieresii is the cause of actinomycosis (wooden tongue) in cattle: a sporadic, insidiously-developing granulomatous infection. In sharp contrast is A. pleuropneumoniae which is responsible for a rapidly spreading often fatal pneumonia, common among intensively reared pigs. Detailed investigation of this organism has provided a much clearer picture of the bacterial factors involved in causing disease. A. equuli similarly causes a potent septicaemia in the neonatal foal; growing apparently unrestricted once infection occurs. Other members of the genus induce characteristic pathogenesis in their preferred host, with one, A. actinomycetemcomitans, being a cause of human periodontal disease. This article reviews recent understanding of the taxonomy and bacteriology of the organisms, and the aetiology, pathogenicity, diagnosis and control of animal disease caused by Actinobacillus species.
Collapse
Affiliation(s)
- A N Rycroft
- Veterinary Bacteriology Group, Department of Pathology and Infectious Diseases, Royal Veterinary College, Hawkshead Lane, North Mymms, AL9 7TA, UK.
| | | |
Collapse
|