Actinobacillus actinomycetemcomitans

Henderson, Brian E.; Wilson, Michael; Sharp, Lindsay; Ward, John M.

doi:10.1099/0022-1317-51-12-1013

Cited by 76 publications

(48 citation statements)

References 116 publications

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“…Aggregatibacter actinomycetemcomitans has been implicated as a key etiological agent of localized aggressive periodontitis [3]. This bacterial species possesses many virulence factors that allow it to colonize the oral epithelium, invade host cells, evade host defenses, and promote connective tissue destruction [4].…”

Section: Introductionmentioning

confidence: 99%

Rhamnus alpinus Leaf Extract Suppresses Lipopolysaccharide-Induced, Monocyte-Derived Macrophage Chemokine Secretion

Chiavaroli

Orlando

et al. 2008

Inflammation

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Periodontitis is a chronic inflammatory disease of bacterial etiology that affects tooth-supporting tissues. The aim of the present study was to investigate the effect of Rhamnus alpinus extracts on lipopolysaccharide (LPS)-induced chemokine secretion by human macrophage-like cells. Phorbol myristic acid-differentiated macrophages were stimulated with Aggregatibacter actinomycetemcomitans LPS in the absence and presence of various concentrations of the extracts. The secretion of interleukin-8 (IL-8), regulated on activation normal T cell expressed and secreted (RANTES), and monocyte chemotactic protein (MCP)-1 was measured using enzyme-linked immunosorbent assays (ELISA). Activation of NF-kappaB p65 was evaluated with an ELISA-based kit containing immobilized oligonucleotides with an NF-kappaB consensus binding site. A. actinomycetemcomitans LPS (1 microg/ml) induced a marked increase in the secretion of IL-8 and RANTES by monocyte-derived macrophages. At non-cytotoxic concentrations, the R. alpinus leaf extract, which contains polyphenols, inhibited the secretion of RANTES and, to a lesser extent, IL-8 in a dose-dependent manner. The extract also decreased the basal levels of MCP-1 secreted by monocyte-derived macrophages. The extract appeared to exert its anti-inflammatory effect by inhibiting NF-kappaB p65 activation. Our results suggest that the leaf extract of R. alpinus possesses a therapeutic potential through its capacity to limit the infiltration of immune cells into periodontal sites. This may impede the progression and aggravation of inflammation given that the migration of immune cells plays an important role in the outcome of periodontitis.

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Section: Introductionmentioning

confidence: 99%

Rhamnus alpinus Leaf Extract Suppresses Lipopolysaccharide-Induced, Monocyte-Derived Macrophage Chemokine Secretion

Chiavaroli

Orlando

et al. 2008

Inflammation

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“…Within the Gammaproteobacteria, one subset belongs to the family Pasteurellaceae and includes Haem. ducreyi, the cause of a sexually transmitted disease known as chancroid (Abeck et al, 1997), Haemophilus parasuis, a commensal organism of the upper respiratory tract associated with septicaemia in pigs (Yue et al, 2009), and A. actinomycetemcomitans, a common contributing agent to chronic periodontitis and localized aggressive periodontitis (Henderson et al, 2002). A second subset of Gammaproteobacteria belongs to the Enterobacteriaceae family and collectively these organisms are responsible for intestinal and urinary tract infections that can lead to systemic spread.…”

Section: Distribution Of Cdt Genes Amongst Bacteriamentioning

confidence: 99%

Cytolethal distending toxin: a conserved bacterial genotoxin that blocks cell cycle progression, leading to apoptosis of a broad range of mammalian cell lineages

et al. 2011

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Cytolethal distending toxin (CDT) is a heterotrimeric AB-type genotoxin produced by several clinically important Gram-negative mucocutaneous bacterial pathogens. Irrespective of the bacterial species of origin, CDT causes characteristic and irreversible cell cycle arrest and apoptosis in a broad range of cultured mammalian cell lineages. The active subunit CdtB has structural homology with the phosphodiesterase family of enzymes including mammalian DNase I, and alone is necessary and sufficient to account for cellular toxicity. Indeed, mammalian cells treated with CDT initiate a DNA damage response similar to that elicited by ionizing radiationinduced DNA double strand breaks resulting in cell cycle arrest and apoptosis. The mechanism of CDT-induced apoptosis remains incompletely understood, but appears to involve both p53-dependent and -independent pathways. While epithelial, endothelial and fibroblast cell lines respond to CDT by undergoing arrest of cell cycle progression resulting in nuclear and cytoplasmic distension that precedes apoptotic cell death, cells of haematopoietic origin display rapid apoptosis following a brief period of cell cycle arrest. In this review, the ecology of pathogens producing CDT, the molecular biology of bacterial CDT and the molecular mechanisms of CDT-induced cytotoxicity are critically appraised. Understanding the contribution of a broadly conserved bacterial genotoxin that blocks progression of the mammalian cell cycle, ultimately causing cell death, should assist with elucidating disease mechanisms for these important pathogens. IntroductionJohnson and Lior's seminal observations in the 1980s identified a novel heat-labile toxin in culture filtrates obtained from certain Escherichia coli, Shigella dysenteriae and Campylobacter jejuni strains which caused distinctive and progressive cytoplasmic and nuclear enlargement of cultured mammalian cells, so called cytolethal distending toxin (CDT), and uncovered a novel paradigm amongst bacterial toxins and virulence mechanisms (Johnson & Lior, 1987, 1988a. It was not until many years later that Scott & Kaper (1994) identified the genes encoding CDT in E. coli, which set the stage for fundamental investigations into the ecology, biochemistry and molecular mechanisms of cellular toxicity associated with this novel bacterial toxin (Table 1). While a secreted protein cytotoxin was identified among Haemophilus (Haem.) ducreyi clinical isolates in the early 1990s by Purvén & Lagergård (1992), it was not until the late 1990s that this cytotoxin was conclusively shown to be encoded by a cdt gene cluster with homology to the previously identified E. coli genes (Cope et al., 1997). This discovery extended the range of niches where CDTproducing bacteria are found to include mucocutaneous surfaces of the genital tract in addition to the intestinal tract. At that time, Pérès et al. (1997) first reported that the mechanism of mammalian cell intoxication by E. coli CDT involved arrest of the cell cycle at the G2/M phase. Soon after, these observa...

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“…The cytotoxic effects of A. actinomycetemcomitans and P. gingivalis were described not once [5], while the possible pathogenetic role of T. forsythensis is less known. It was hypothesized that this bacterium is involved in the loss of the dentogingival adhesion [13].…”

Section: Parametersmentioning

confidence: 99%

Bacterial markers of periodontal diseases and their practical significance in dentistry

et al. 2007

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The incidence and prevalence of Actinobacillus actinomycetemcomitans, Porphyronmonas gingivalis, and Tannerella forsythensis in specimens of subgingival dental deposit were evaluated in 495 residents of St. Petersburg aged 6-82 years. The microorganisms were detected by gene-specific PCR of 16S rDNA. In accordance with age-specific increase in the incidence of gingival diseases, the percentage of samples containing T. forsythensis and P. gingivalis was significantly higher in adult and elderly patients in comparison with adolescents. The presence of T. forsythensis significantly correlated with the presence of gingivitis and dental deposit. In addition, the incidence of T. forsythensis was significantly higher in tobacco smokers. These results attest to a relationship between T. forsythensis infection and more frequent periodontal diseases associated with aging and tobacco smoking.

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Actinobacillus actinomycetemcomitans

Cited by 76 publications

References 116 publications

Rhamnus alpinus Leaf Extract Suppresses Lipopolysaccharide-Induced, Monocyte-Derived Macrophage Chemokine Secretion

Rhamnus alpinus Leaf Extract Suppresses Lipopolysaccharide-Induced, Monocyte-Derived Macrophage Chemokine Secretion

Cytolethal distending toxin: a conserved bacterial genotoxin that blocks cell cycle progression, leading to apoptosis of a broad range of mammalian cell lineages

Bacterial markers of periodontal diseases and their practical significance in dentistry

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