Fusobacterium nucleatum is an opportunistic pathogenic bacterium that can be enriched in colorectal cancer tissues, affecting multiple stages of colorectal cancer development. The two-component system plays an important role in the regulation and expression of genes related to pathogenic resistance and pathogenicity. In this paper, we focused on the CarRS two-component system of F. nucleatum, and the histidine kinase protein CarS was recombinantly expressed and characterized. Several online software such as SMART, CCTOP and AlphaFold2 were used to predict the secondary and tertiary structure of the CarS protein. The results showed that CarS is a membrane protein with two transmembrane helices and contains 9 α-helices and 12 β-folds. CarS protein is composed of two domains, one is the N-terminal transmembrane domain (amino acids 1-170), the other is the C-terminal intracellular domain. The latter is composed of a signal receiving domain (histidine kinases, adenylyl cyclases, methyl-accepting proteins, prokaryotic signaling proteins, HAMP), a phosphate receptor domain (histidine kinase domain, HisKA), and a histidine kinase catalytic domain (histidine kinase-like ATPase catalytic domain, HATPase_c). Since the full-length CarS protein could not be expressed in host cells, a fusion expression vector pET-28a(+)-MBP-TEV-CarS_cyto was constructed based on the characteristics of secondary and tertiary structures, and overexpressed in Escherichia coli BL21-Codonplus(DE3)RIL. CarS_cyto-MBP protein was purified by affinity chromatography, ion-exchange chromatography, and gel filtration chromatography with a final concentration of 20 mg/ml. CarS_cyto-MBP protein showed both protein kinase and phosphotransferase activities, and the MBP tag had no effect on the function of CarS_cyto protein. The above results provide a basis for in-depth analysis of the biological function of the CarRS two-component system in F. nucleatum.
Humans ; Histidine Kinase/metabolism* ; Fusobacterium nucleatum/metabolism* ; Automobiles ; Protein Kinases/genetics* ; Escherichia coli/metabolism* ; Colorectal Neoplasms

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.
Humans ; Fusobacterium nucleatum/metabolism* ; NF-kappa B/metabolism* ; Periodontal Ligament/metabolism* ; Signal Transduction ; Fusobacterium Infections/pathology* ; Stem Cells/metabolism*

Humans ; Young Adult ; Fusobacterium necrophorum ; Pharyngitis/microbiology* ; Streptococcal Infections ; Sepsis/diagnosis*

Fusobacterium nucleatum (Fn) is an oral anaerobic bacterium that has recently been found to colonize on the surface of colorectal cancer cells in humans, and its degree of enrichment is highly negatively correlated with the prognosis of tumor treatment. Numerous studies have shown that Fn is involved in the occurrence and development of colorectal cancer (CRC), and Fn interacts with multiple components in the tumor microenvironment to increase tumor resistance. In recent years, researchers have begun using nanomedicine to inhibit Fn's proliferation at the tumor site or directly target Fn to treat CRC. This review summarizes the mechanism of Fn in promoting CRC and the latest research progress on Fn-related CRC therapy using different nanomaterials. Finally, the applications perspective of nanomaterials in Fn-promoted CRC therapy was prospected.
Humans ; Colorectal Neoplasms/pathology* ; Fusobacterium nucleatum/genetics* ; Base Composition ; RNA, Ribosomal, 16S ; Phylogeny ; Sequence Analysis, DNA ; Tumor Microenvironment

Periodontal pathogens are the main pathogenic factor of periodontitis. Periodontal pathogens have a large variety of virulence factors such as lipopolysaccharide, fimbriae and proteases, which enables the pathogens to infect periodontal tissues and stimulate the secretion of inflammatory cytokines, causing chronic systemic inflammation. Periodontal pathogens may invade multiple systems such as the circulatory system, immune system, respiratory system and digestive system to cause systematic diseases. Recent studies have shown that periodontal pathogens may have close relations with systemic diseases such as cardiovascular disease, diabetes, rheumatoid arthritis, and cancer. Among the periodontal pathogens, can be found in atherosclerotic plaques to impairing the function of the vascular endothelium; may also increase the level of inflammatory factors such as TNF-α to promote insulin resistance and diabetes. Many of the periodontal pathogens such as , and can be detected in the synovial fluid of rheumatoid arthritis patients, suggesting their involvement in the pathogenesis of rheumatoid arthritis. may cause alterations in the intestinal microbiome in mice and promote the occurrence of intestinal tumors. Herein we review the recent progresses in the relationship between periodontal pathogens and systemic diseases.
Aggregatibacter actinomycetemcomitans ; Animals ; Fusobacterium nucleatum ; Humans ; Insulin Resistance ; Periodontitis ; Porphyromonas gingivalis ; Prevotella intermedia

Anaerobic infections have been reported to be responsible for 3–10% of pyogenic liver abscesses in Korea, and reported anaerobes include Fusobacterium, Bacillus fragilis, and Bacteroides melaninogenicus. Parvimonas micra is an anaerobic, Gram-positive, non-spore-forming bacterial species and a constituent of normal flora on skin, vagina, gastrointestinal tract, and oral cavity that can cause opportunistic infections. However, it has only rarely been reported to be a cause of liver abscess; only one such case has been reported in Korea. We experienced a case of concomitant liver and brain abscesses caused by Parvimonas micra in a non-immunodeficient 65-year-old female patient without diabetes or periodontal disease. Parvimonas micra infection was confirmed by blood culture using VITEK® 2 cards and by bacterial 16s ribosomal RNA gene sequencing. We conclude that we should not overlook anaerobes as a cause of liver abscess.
Aged ; Bacillus ; Bacteria, Anaerobic ; Brain Abscess ; Brain ; Female ; Fusobacterium ; Gastrointestinal Tract ; Humans ; Korea ; Liver Abscess ; Liver Abscess, Pyogenic ; Liver ; Mouth ; Opportunistic Infections ; Periodontal Diseases ; Prevotella melaninogenica ; RNA, Ribosomal, 16S ; Skin ; Vagina

BACKGROUND: This study aimed to investigate the prognostic impact of intratumoral Fusobacterium nucleatum in colorectal cancer (CRC) treated with adjuvant chemotherapy. METHODS: F. nucleatum DNA was quantitatively measured in a total of 593 CRC tissues retrospectively collected from surgically resected specimens of stage III or high-risk stage II CRC patients who had received curative surgery and subsequent oxaliplatin-based adjuvant chemotherapy (either FOLFOXor CAPOX). Each case was classified into one of the three categories: F. nucleatum–high, –low, or –negative. RESULTS: No significant differences in survival were observed between the F.nucleatum–high and –low/negative groups in the 593 CRCs (p = .671). Subgroup analyses according to tumor location demonstrated that disease-free survival was significantly better in F.nucleatum–high than in –low/negative patients with non-sigmoid colon cancer (including cecal, ascending, transverse, and descending colon cancers; n = 219; log-rank p = .026). In multivariate analysis, F. nucleatum was determined to be an independent prognostic factor in non-sigmoid colon cancers (hazard ratio, 0.42; 95% confidence interval, 0.18 to 0.97; p = .043). Furthermore, the favorable prognostic effect of F. nucleatum–high was observed only in a non-microsatellite instability-high (non-MSI-high) subset of non-sigmoid colon cancers (log-rank p = 0.014), but not in a MSI-high subset (log-rank p = 0.844), suggesting that the combined status of tumor location and MSI may be a critical factor for different prognostic impacts of F. nucleatum in CRCs treated with adjuvant chemotherapy. CONCLUSIONS: Intratumoral F. nucleatum load is a potential prognostic factor in a non-MSI-high/non-sigmoid/non-rectal cancer subset of stage II/III CRCs treated with oxaliplatin-based adjuvant chemotherapy.
Chemotherapy, Adjuvant ; Colon, Descending ; Colonic Neoplasms ; Colorectal Neoplasms ; Disease-Free Survival ; DNA ; Fusobacterium nucleatum ; Fusobacterium ; Gastrointestinal Microbiome ; Humans ; Microsatellite Instability ; Microsatellite Repeats ; Multivariate Analysis ; Prognosis ; Retrospective Studies

PURPOSE: The purpose of this study was to evaluate the antimicrobial effects of a toothbrush with light-emitting diodes (LEDs) on periodontitis-associated dental biofilm attached to a zirconia surface by static and dynamic methods. MATERIALS AND METHODS: Zirconia disks (12 mm diameter, 2.5 mm thickness) were inserted into a 24-well plate (static method) or inside a Center for Disease Control and Prevention (CDC) biofilm reactor (dynamic method) to form dental biofilms using Streptococcus gordonii and Fusobacterium nucleatum. The disks with biofilm were subdivided into five treatment groups-control, commercial photodynamic therapy (PDT), toothbrush alone (B), brush with LED (BL), and brush with LED+erythrosine (BLE). After treatment, the disks were agitated to detach the bacteria, and the resulting solutions were spread directly on selective agar. The number of viable bacteria and percentage of bacterial reduction were determined from colony counts. Scanning electron microscopy (SEM) was performed to visualize alterations in bacterial morphology. RESULTS: No significant difference in biofilm formation was observed between dynamic and static methods. A significant difference was observed in the number of viable bacteria between the control and all experimental groups (P < 0.05). The percentage of bacterial reduction in the BLE group was significantly higher than in the other treated groups (P < 0.05). SEM revealed damaged bacterial cell walls in the PDT, BL, and BLE groups, but intact cell walls in the control and B groups. CONCLUSION: The findings suggest that an LED toothbrush with erythrosine is more effective than other treatments in reducing the viability of periodontitis-associated bacteria attached to zirconia in vitro.
Agar ; Bacteria ; Biofilms ; Cell Wall ; Centers for Disease Control and Prevention (U.S.) ; Dihydroergotamine ; Erythrosine ; Fusobacterium nucleatum ; In Vitro Techniques ; Microscopy, Electron, Scanning ; Photochemotherapy ; Streptococcus gordonii ; Toothbrushing

PURPOSE: Dysbiosis of gut microbiota has been reported to participate in the pathogenesis of colorectal cancer, but changes in microbiota due to radiotherapy have not been studied. In this study, we tried to elucidate the changes in the microbiome in rectal cancer after chemoradiotherapy using RNA sequencing analysis.MATERIALS AND METHODS: We included 11 pairs of human rectal cancer tissues before and after irradiation between August 2016 and December 2017 and performed RNA sequencing analysis. Mapped reads to human reference genomes were used for pair-wise transcriptome comparisons, and unmapped (non-human) reads were then mapped to bacterial marker genes using PathSeq.RESULTS: At microbiome level, interindividual variability of mucosal microbiota was greater than the change in microbial composition during radiotherapy. This indicates that rapid homeostatic recovery of the mucosal microbial composition takes place short after radiotherapy. At single microbe level, Prevotella and Fusobacterium, which were identified as important causative microbes of the initiation and progression of rectal cancer were decreased by radiotherapy. Moreover, changes in Prevotella were associated with changes in the human transcriptome of rectal cancer. We also found that there was a gene cluster that increased and decreased in association with changes in microbial composition by chemoradiation.CONCLUSION: This study revealed changes in tumor-associated microbial community by irradiation in rectal cancer. These findings can be used to develop a new treatment strategy of neoadjuvant therapy for locally advanced rectal cancer by overcoming radio-resistance or facilitating radio-sensitivity.
Chemoradiotherapy ; Colorectal Neoplasms ; Dysbiosis ; Fusobacterium ; Gastrointestinal Microbiome ; Genes, vif ; Genome ; Humans ; Microbiota ; Neoadjuvant Therapy ; Prevotella ; Radiotherapy ; Rectal Neoplasms ; Sequence Analysis, RNA ; Transcriptome

BACKGROUND: Smoking exerts an adverse effect on the periodontal tissue by reorganizing the ecosystem of oral microorganisms and is considered to be an important factor in the development of periodontal disease. Although cross-sectional studies on smokers and non-smokers have been attempted to investigate the microbial differences in periodontal oral cavity, only few studies have been conducted to investigate the changes in oral microorganisms during smoking cessation. The purpose of this study was to investigate the changes of bacteria in saliva and gingival crevicular fluid (GCF) over a period of one year among 11 smokers trying to quit smoking.METHODS: Eleven smokers trying to quit smoking visited the clinic at baseline, two weeks, two months, four months, six months, and 12 months to give saliva and GCF samples. The amounts of 16S rRNA, Porphyromonas gingivalis, Treponema denticola, Prevotella intermedia, Fusobacterium nucleatum subsp. nucleatum, Streptococcus mutans, and Streptococcus sobrinus in saliva and GCF were quantified using real-time polymerase chain reaction TaqMan probe assay. The results were analyzed by nonparametric statistical analysis using Friedman test and Spearman correlation coefficient.RESULTS: After cessation of smoking, the amounts of 16S rRNA corresponding to P. gingivalis, F. nucleatum, P. intermedia, and T. denticola in saliva decreased and then again increased significantly. The amount of F. nucleatum 16S rRNA in GCF decreased significantly after smoking cessation. Positive correlations were observed between 16S rRNA and F. nucleatum and between F. nucleatum and T. denticola in saliva and GCF.CONCLUSION: Even if the number of subjects in this study was small, we suggest that smoking cessation may reduce the total bacterial amount and F. nucleatum in GCF. However, the results regarding changes in the microbial ecosystem due to smoking or smoking cessation were inconsistent. Therefore, further in-depth studies need to be carried out.
Bacteria ; Bacterial Load ; Cross-Sectional Studies ; Ecosystem ; Fusobacterium nucleatum ; Gingival Crevicular Fluid ; Mouth ; Periodontal Diseases ; Porphyromonas gingivalis ; Prevotella intermedia ; Real-Time Polymerase Chain Reaction ; Saliva ; Smoke ; Smoking Cessation ; Smoking ; Streptococcus mutans ; Streptococcus sobrinus ; Treponema denticola