Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Dent Res ; 99(6): 604-612, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32091956

RESUMO

Oral cancer, predominantly oral squamous cell carcinoma (OSCC), is the eighth-most common cancer worldwide, with a 5-y survival rate <50%. There are numerous risk factors for oral cancer, among which periodontal disease is gaining increasing recognition. The creation of a sustained dysbiotic proinflammatory environment by periodontal bacteria may serve to functionally link periodontal disease and oral cancer. Moreover, traditional periodontal pathogens, such as Porphyromonas gingivalis, Fusobacterium nucleatum, and Treponema denticola, are among the species most frequently identified as being enriched in OSCC, and they possess a number of oncogenic properties. These organisms share the ability to attach and invade oral epithelial cells, and from there each undergoes its own unique molecular dialogue with the host epithelium, which ultimately converges on acquired phenotypes associated with cancer, including inhibition of apoptosis, increased proliferation, and activation of epithelial-to-mesenchymal transition leading to increased migration of epithelial cells. Additionally, emerging properties of structured bacterial communities may increase oncogenic potential, and consortia of P. gingivalis and F. nucleatum are synergistically pathogenic within in vivo oral cancer models. Interestingly, however, some species of oral streptococci can antagonize the phenotypes induced by P. gingivalis, indicating functionally specialized roles for bacteria in oncogenic communities. Transcriptomic data support the concept that functional, rather than compositional, properties of oral bacterial communities have more relevance to cancer development. Collectively, the evidence is consistent with a modified polymicrobial synergy and dysbiosis model for bacterial involvement in OSCC, with driver mutations generating a conducive microenvironment on the epithelial boundary, which becomes further dysbiotic by the synergistic action of bacterial communities.


Assuntos
Carcinoma de Células Escamosas , Neoplasias Bucais , Fusobacterium nucleatum , Humanos , Porphyromonas gingivalis , Microambiente Tumoral
2.
Mol Oral Microbiol ; 30(3): 242-52, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25418117

RESUMO

Periodontal diseases are semi-ubiquitous and caused by chronic, plaque-induced inflammation. The 55-kDa immunodominant RagB outer membrane protein of Porphyromonas gingivalis, a keystone periodontal pathogen, has been proposed to facilitate nutrient transport. However, potential interactions between RagB and the innate response have not been examined. We determined that RagB exposure led to the differential and dose-related expression of multiple genes encoding proinflammatory mediators [interleukin-1α (IL-1α), IL-1ß, IL-6, IL-8 and CCL2; all P < 0.05] in primary human monocytes and to the secretion of tumor necrosis factor and IL-8, but not interferon-γ or IL-12. RagB was shown to be a Toll-like receptor 2 (TLR2) and TLR4 agonist that activated signal transducer and activator of transcription 4 and nuclear factor-κB signaling, as determined by a combination of blocking antibodies, pharmaceutical inhibitors and gene silencing. In keeping, a ΔragB mutant similarly exhibited reduced inflammatory capacity, which was rescued by ragB complementation. These results suggest that RagB elicits a major pro-inflammatory response in primary human monocytes and, therefore, could play an important role in the etiology of periodontitis and systemic sequelae.


Assuntos
Proteínas de Bactérias/imunologia , Porphyromonas gingivalis/genética , Fator de Transcrição STAT4/agonistas , Receptor 2 Toll-Like/agonistas , Receptor 4 Toll-Like/agonistas , Proteínas de Bactérias/genética , Citocinas/imunologia , Gengiva/imunologia , Humanos , Lipopolissacarídeos/imunologia , Monócitos/imunologia , NF-kappa B/imunologia , Periodontite/imunologia , Fosforilação , Transdução de Sinais/imunologia
3.
Mol Oral Microbiol ; 28(2): 102-13, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23193955

RESUMO

A gingival crevice model (epithelial cell-Porphyromonas gingivalis-neutrophil) was established and used to profile gingipain, matrix metalloproteinase (MMP), MMP mediators [neutrophil gelatinase-associated lipocalin (NGAL) and tissue inhibitor of metalloproteinases 1 (TIMP-1)] and cytokine networks. Smoking is the primary environmental risk factor for periodontitis. Therefore, the influence of cigarette smoke extract (CSE) was also monitored in the same model. Porphyromonas gingivalis alone induced low levels of interleukin-1ß and interleukin-8 from epithelial cells, but high levels of both cytokines were produced on the addition of neutrophils. Exposure to CSE (100 and 1000 ng ml(-1) nicotine equivalency) significantly compromised P. gingivalis-induced cytokine secretion (both P < 0.05). P. gingivalis induced impressive secretion of NGAL (P < 0.05) that was not influenced by CSE. The influence of CSE on gingipain production was strain-specific. Purified gingipains effectively and rapidly degraded both TIMP-1 and MMP-9. Induction of large amounts of NGAL, degradation of TIMP-1, and increased gingipain activity would each be expected to prolong collagen degradation and promote disease progression. However, gingipains also degrade MMP-9. Hence, P. gingivalis exerts a complex influence on the proteolytic balance of a gingival crevice model. Exposure to CSE reduces the proinflammatory cytokine burden, which may be expected to promote P. gingivalis survival. In addition to novel findings that provide mechanistic insight into periodontal disease progression, these results are in keeping with the recognized clinical dogma of decreased inflammation/increased disease in smokers. This straightforward gingival crevice model is established as a suitable vehicle for the elucidation of mechanisms that contribute to susceptibility to periodontitis.


Assuntos
Gengiva/microbiologia , Neutrófilos/fisiologia , Porphyromonas gingivalis/fisiologia , Proteínas de Fase Aguda/análise , Adesinas Bacterianas/análise , Adesinas Bacterianas/farmacologia , Técnicas de Cultura de Células , Células Cultivadas , Cisteína Endopeptidases/análise , Cisteína Endopeptidases/farmacologia , Citocinas/análise , Progressão da Doença , Suscetibilidade a Doenças , Células Epiteliais/enzimologia , Células Epiteliais/fisiologia , Cisteína Endopeptidases Gingipaínas , Gengiva/imunologia , Humanos , Mediadores da Inflamação/análise , Interleucina-1beta/análise , Interleucina-8/análise , Lipocalina-2 , Lipocalinas/análise , Metaloproteinase 8 da Matriz/análise , Metaloproteinase 9 da Matriz/análise , Metaloproteinase 9 da Matriz/efeitos dos fármacos , Viabilidade Microbiana , Neutrófilos/enzimologia , Nicotina/farmacologia , Porphyromonas gingivalis/imunologia , Proteínas Proto-Oncogênicas/análise , Fumaça , Inibidor Tecidual de Metaloproteinase-1/análise , Inibidor Tecidual de Metaloproteinase-1/efeitos dos fármacos , Nicotiana
4.
J Dent Res ; 90(1): 47-52, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21041552

RESUMO

We hypothesized that tobacco smoke induces alterations to the 3-OH fatty acids present in lipid A in a manner consistent with a microflora of reduced inflammatory potential. Whole saliva samples and full-mouth clinical periodontal recordings were obtained from persons with (22 smokers; 15 non-smokers) and without (14 smokers; 15 non-smokers) chronic periodontitis. Clear differences in the contributions of multiple saturated 3-OH fatty acid species were noted in the group with disease compared with healthy individuals. Increases in the long-chain fatty acids associated with anaerobic bacterial periodontopathogens, particularly 3-OH-C(i17.0) (146.7%, relative to controls), were apparent. Significant reductions in the 3-OH fatty acids associated with the consensus (high potency) enteric LPS structure (3-OH-C(12.0) and 3-OH-C(14.0); 33.3% and 15.8% reduction, respectively) were noted in smokers compared with non-smokers with chronic periodontitis. Thus, smoking is associated with specific structural alterations to the lipid-A-derived 3-OH fatty acid profile in saliva that are consistent with an oral microflora of reduced inflammatory potential. These findings provide much-needed mechanistic insight into the established clinical conundrum of increased infection with periodontal pathogens but reduced clinical inflammation in smokers.


Assuntos
Periodontite Crônica/metabolismo , Ácidos Graxos/análise , Fumar/metabolismo , Adulto , Bactérias Anaeróbias/metabolismo , Periodontite Crônica/microbiologia , Cotinina/análise , Índice de Placa Dentária , Feminino , Hemorragia Gengival/metabolismo , Bactérias Gram-Negativas/metabolismo , Humanos , Lipídeo A/análise , Lipopolissacarídeos/análise , Masculino , Pessoa de Meia-Idade , Boca/microbiologia , Perda da Inserção Periodontal/metabolismo , Índice Periodontal , Bolsa Periodontal/metabolismo , Saliva/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...