ABSTRACT
Fusobacterium nucleatum (F. nucleatum) is an early pathogenic colonizer in periodontitis, but the host response to infection with this pathogen remains unclear. In this study, we built an F. nucleatum infectious model with human periodontal ligament stem cells (PDLSCs) and showed that F. nucleatum could inhibit proliferation, and facilitate apoptosis, ferroptosis, and inflammatory cytokine production in a dose-dependent manner. The F. nucleatum adhesin FadA acted as a proinflammatory virulence factor and increased the expression of interleukin(IL)-1β, IL-6 and IL-8. Further study showed that FadA could bind with PEBP1 to activate the Raf1-MAPK and IKK-NF-κB signaling pathways. Time-course RNA-sequencing analyses showed the cascade of gene activation process in PDLSCs with increasing durations of F. nucleatum infection. NFκB1 and NFκB2 upregulated after 3 h of F. nucleatum-infection, and the inflammatory-related genes in the NF-κB signaling pathway were serially elevated with time. Using computational drug repositioning analysis, we predicted and validated that two potential drugs (piperlongumine and fisetin) could attenuate the negative effects of F. nucleatum-infection. Collectively, this study unveils the potential pathogenic mechanisms of F. nucleatum and the host inflammatory response at the early stage of F. nucleatum infection.
Subject(s)
Humans , Fusobacterium nucleatum/metabolism , NF-kappa B/metabolism , Periodontal Ligament/metabolism , Signal Transduction , Fusobacterium Infections/pathology , Stem Cells/metabolismABSTRACT
Fusobacterium nucleatum is considered a bridge organism between earlier and later colonizers in dental biofilms and a putative periodontopathogen. In Dentistry, antimicrobial agents are used for treatment and control of infectious diseases associated with dental plaque. Antiseptics have been used in association with antibiotics to reduce infections after oral surgeries. In this study, the influence of subinhibitory concentrations (SC) of chlorhexidine, triclosan, penicillin G and metronidazole, on hydrophobicity, adherence to oral epithelial cells, and ultra-structure of F. nucleatum was examined. All isolates were susceptible to chlorhexidine, triclosan, and metronidazole; however, most of the isolates were susceptible to penicillin G, and all of them were hydrophilic when grown with or without antimicrobials. Adherence was decreased by all antimicrobials. Results suggest that adherence of F. nucleatum was influenced by adhesins because structures such as fimbries or capsule were not observed by transmission electronic microscope.
Subject(s)
Anti-Bacterial Agents/isolation & purification , Anti-Bacterial Agents , Fusobacterium nucleatum , In Vitro Techniques , Fusobacterium Infections/diagnosis , Fusobacterium Infections/pathology , Periodontium , Methods , MethodsABSTRACT
The aim of this study was to carry out a microbiological evaluation of sites with and without clinical evidence of moderate and severe periodontitis and their correlation with clinical parameters. A total of 52 disease sites and 10 healthy sites were selected according to clinical criteria. The following clinical indexes were measured for all the sites: plaque index, gingival index, blood on probing, depth on probing and insertion level. Samples of subgingival plaque were collected for culture and for differential counts of microbial morphotypes. In disease sites the most frequently isolated were: Prevotella intermedia/nigrescens (65), Porphyromonas gingivalis (23), Actinobacillus actinomycetemcomitans (23), Fusobacterium nucleatum (10) and Peptostreptococcus sp. (31). The aerobic gram-positive microflora was predominant in healthy sites. Significant differences were observed in microbial morphotypes between healthy and disease sites: cocci 18.71 and 78.90, motile rods 46.12 and 16.70, total spirochetes 26.48 and 2.80, respectively. The presence of motile rods, spirochetes and P. intermedia/nigrescens were the parameters with most sensitivity to suspect periodontal disease. There were significant differences in the subgingival microflora between healthy and disease sites in patients with moderate and severe periodontitis.
Subject(s)
Humans , Adult , Middle Aged , Periodontitis , Aggregatibacter actinomycetemcomitans , Argentina , Fusobacterium nucleatum , Gram-Positive Bacterial Infections/epidemiology , Gram-Positive Bacterial Infections/microbiology , Gram-Positive Bacterial Infections/pathology , Actinobacillus Infections/epidemiology , Actinobacillus Infections/microbiology , Actinobacillus Infections/pathology , Bacteroidaceae Infections/epidemiology , Bacteroidaceae Infections/microbiology , Bacteroidaceae Infections/pathology , Fusobacterium Infections/epidemiology , Fusobacterium Infections/microbiology , Fusobacterium Infections/pathology , Peptostreptococcus , Periodontal Index , Periodontitis , Dental Plaque/microbiology , Porphyromonas gingivalis , Prevotella intermedia , Severity of Illness IndexABSTRACT
"Fusobacterium nucleatum" is indigenous of the human oral cavity and has been involved in different infectious processes. The production of bacteriocin-like substances may be important in regulation of bacterial microbiota in oral cavity. The ability to produce bacteriocin-like substances by 80 oral "F. nucleatum" isolates obtained from periodontal patients, healthy individuals and "Cebus apella" monkeys, was examinated. 17.5(per cent) of all tested isolates showed auto-antagonism and 78.8(per cent) iso- or hetero-antagonism. No isolate from monkey was capable to produce auto-inhibition. In this study, the antagonistic substances production was variable in all tested isolates. Most of the "F. nucleatum" showed antagonistic activity against tested reference strains. These data suggest a possible participation of these substances on the oral microbial ecology in humans and animals. However, the role of bacteriocins in regulating dental plaque microbiota "in vivo" is discussed