The essential role of toll like receptor-4 in the control of Aggregatibacter actinomycetemcomitans infection in mice.
OBJECTIVE
Aggregatibacter actinomycetemcomitans is an oral Gram-negative bacterium that contributes to periodontitis progression. Isolated antigens from A. actinomycetemcomitans could be activating innate immune cells through Toll-like receptors (TLRs). In this study, we evaluated the role of TLR4 in the control of A. actinomycetemcomitans infection.


METHODS
We examined the mechanisms that modulate the outcome of A. actinomycetemcomitans-induced periodontal disease in TLR4(-/-) mice. The production of cytokines was evaluated by ELISA. The bacterial load was determined by counting the number of colony-forming units per gram of tissue.


RESULTS
The results showed that TLR4-deficient mice developed less severe periodontitis after A. actinomycetemcomitans infection, characterized by significantly lower bone loss and inflammatory cell migration to periodontal tissues. However, the absence of TLR4 facilitated the A. actinomycetemcomitans dissemination. Myeloperoxidase activity was diminished in the periodontal tissue of TLR4(-/-) mice. We observed a significant reduction in the production of tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1beta in the periodontal tissue of TLR4(-/-) mice.


CONCLUSIONS
The results of this study highlighted the role of TLR4 in controlling A. actinomycetemcomitans infection.
Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
Hayana Ramos
HR
Lima
Valéria
V
Gelani
Ana Paula
AP
Fernandes
Thaís Helena
TH
Gasparoto
Sérgio Aparecido
SA
Torres
Carlos Ferreira
CF
Santos
Gustavo Pompermaier
GP
Garlet
João Santana
JS
da Silva
Ana Paula
AP
Campanelli
D000189:Actinobacillus Infections / Q000150:complications / Q000276:immunology* / Q000382:microbiology; D016976:Aggregatibacter actinomycetemcomitans / Q000276:immunology* / Q000472:pathogenicity; D016301:Alveolar Bone Loss / Q000209:etiology / Q000276:immunology / Q000382:microbiology; D000818:Animals; D053583:Interleukin-1beta / Q000378:metabolism; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D018345:Mice, Knockout; D010518:Periodontitis / Q000209:etiology / Q000276:immunology* / Q000382:microbiology; D009195:Peroxidase / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000276:immunology* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D053583:Interleukin-1beta; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; D009195:Peroxidase