Fusobacterium nucleatum and its associated systemic diseases: epidemiologic studies and possible mechanisms

Fusobacterium nucleatum in tumors: from tumorigenesis to tumor metastasis and tumor resistance

Fusobacterium nucleatum, an anaerobic Gram-negative bacterium primarily residing in the oral cavity, has garnered significant attention for its emerging role in cancer progression and prognosis. While extensive research has revealed mechanistic links between Fusobacterium nucleatum and colorectal cancer, a comprehensive review spanning its presence and metastatic implications in cancers beyond colorectal origin is conspicuously absent. This paper broadens our perspective from colorectal cancer to various malignancies associated with Fusobacterium nucleatum, including oral, pancreatic, esophageal, breast, and gastric cancers. Our central focus is to unravel the mechanisms governing Fusobacterium nucleatum colonization, initiation, and promotion of metastasis across diverse cancer types. Additionally, we explore Fusobacterium nucleatum's adverse impacts on cancer therapies, particularly within the domains of immunotherapy and chemotherapy. Furthermore, this paper underscores the clinical research significance of Fusobacterium nucleatum as a potential tumor biomarker and therapeutic target, offering a novel outlook on its applicability in cancer detection and prognostic assessment.

Fusobacterium nucleatum-infected periodontitis promotes renal interstitial fibrosis in rats through the TGF-β/SMAD2/3 and β-catenin signaling pathways

OBJECTIVES

Periodontitis is associated with Fusobacterium nucleatum (F.n) infection. Although the colonization of renal tissue by F.n is well documented, its specific role in kidney disease has yet to be determined. This study aimed to investigate the potential association between F.n-induced periodontitis and renal interstitial fibrosis.

METHODS

The rat gingival sulcus was injected with F.n suspension, while the control group (NC) was injected with PBS. The levels of total protein (TP), albumin (ALB), creatinine, and urea nitrogen (BUN) in rat serum and/or urine were quantified using the appropriate kits. Renal interstitial fibrosis and epithelial-mesenchymal transition (EMT) were evaluated in rats using Masson staining, Periodic Schiff-Methenamine (PASM) staining, and immunohistochemical staining. The levels of fibrosis- and EMT-related proteins and the TGF-β/SMAD2/3 and β-catenin signaling pathways were determined using Western blot analysis. F.n in the kidney tissues was quantitatively determined using bacterial 16S rRNA technology.

RESULTS

Serum levels of TP, ALB, creatinine, and BUN were not significantly decreased in F.n-infected rats with periodontitis. The levels of creatinine and ALB in the urine were not statistically different between two groups. Masson and PASM staining showed that F.n-induced periodontitis could promote renal interstitial fibrosis in rats. The levels of collagen I, fibronectin (FN), vimentin, and α-SMA were upregulated in the kidney tissues of rats with F.n-induced periodontitis and in F.n-treated HK-2 cells. However, E-cadherin levels were reduced. F.n promoted renal interstitial and HK-2 cell fibrosis in rats by modulating the TGF-β/SMAD2/3 and β-catenin signaling pathways. F.n colonization increased renal interstitial fibrosis in rats.

CONCLUSION

F.n-induced periodontitis promoted EMT by activating the TGF-β/SMAD2/3 and β-catenin signaling pathways, thus promoting renal interstitial fibrosis in rats.

Targeted elimination of Fusobacterium nucleatum alleviates periodontitis

Background

Fusobacterium nucleatum, a pathobiont in periodontal disease, contributes to alveolar bone destruction. We assessed the efficacy of a new targeted antimicrobial, FP-100, in eradicating F. nucleatum from the oral microbial community in vitro and in vivo and evaluated its effectiveness in reducing bone loss in a mouse periodontitis model.

Methods

A multispecies bacterial community was cultured and treated with two concentrations of FP-100 over two days. Microbial profiles were examined at 24-h intervals using 16S rRNA sequencing. A ligature-induced periodontitis mouse model was employed to test FP-100 in vivo.

Results

FP-100 significantly reduced Fusobacterium spp. within the in vitro community (p < 0.05) without altering microbial diversity at a 2 μM concentration. In mice, cultivable F. nucleatum was undetectable in FP-100-treated ligatures but persistent in controls. Beta diversity plots showed distinct microbial structures between treated and control mice. Alveolar bone loss was significantly reduced in the FP-100 group (p = 0.018), with concurrent decreases in gingival IL-1β and TNF-α expression (p = 0.052 and 0.018, respectively).

Conclusion

FP-100 effectively eliminates F. nucleatum from oral microbiota and significantly reduces bone loss in a mouse periodontitis model, demonstrating its potential as a targeted therapeutic agent for periodontal disease.

Unveiling the Hidden Links: Periodontal Disease, Fusobacterium Nucleatum, and Cancers

PURPOSE OF REVIEW

Fusobacterium nucleatum (F. nucleatum), an anaerobic, gram-negative microbe, commonly found in human dental biofilm and the gut flora. It has long been known to have a higher concentration in periodontal disease and has recently been implicated in both oral and distant cancers such as colorectal, gastrointestinal, esophageal, breast, pancreatic hepatocellular, and genitourinary cancers. However, the mechanism of its involvement in the development of cancer has not been fully discussed. This review aims to cover biological molecular and clinical aspects of F. nucleatum and cancers.

RECENT FINDINGS

Studies indicate F. nucleatum promotes tumor development through chronic inflammation, immune evasion, cell proliferation activation, and direct cell interactions, as in oral squamous cell carcinoma (OSCC). In colorectal cancer (CRC), F. nucleatum contributes to tumorigenesis through β-catenin signaling and NF-κB activation. It also induces autophagy, leading to chemoresistance in CRC and esophageal cancers, and enhances tumor growth and metastasis in breast cancer by reducing T-cell infiltration. F. nucleatum is linked to carcinogenesis and increased bacterial diversity in OSCC, with improved oral hygiene potentially preventing OSCC. F. nucleatum triggers cancer by causing mutations and epigenetic changes through cytokines and reactive oxygen species. It also promotes chemoresistance in CRC. F. nucleatum may potentially serve as a diagnostic tool in various cancers, with non-invasive detection methods available. Further investigation is needed to discover its potential in the diagnosis and treatment of OSCC and other cancers.

The oral-gut microbiome axis in inflammatory bowel disease: from inside to insight

Inflammatory bowel disease (IBD) is an idiopathic and persistent inflammatory illness of the bowels, leading to a substantial burden on both society and patients due to its high incidence and recurrence. The pathogenesis of IBD is multifaceted, partly attributed to the imbalance of immune responses toward the gut microbiota. There is a correlation between the severity of the disease and the imbalance in the oral microbiota, which has been discovered in recent research highlighting the role of oral microbes in the development of IBD. In addition, various oral conditions, such as angular cheilitis and periodontitis, are common extraintestinal manifestations (EIMs) of IBD and are associated with the severity of colonic inflammation. However, it is still unclear exactly how the oral microbiota contributes to the pathogenesis of IBD. This review sheds light on the probable causal involvement of oral microbiota in intestinal inflammation by providing an overview of the evidence, developments, and future directions regarding the relationship between oral microbiota and IBD. Changes in the oral microbiota can serve as markers for IBD, aiding in early diagnosis and predicting disease progression. Promising advances in probiotic-mediated oral microbiome modification and antibiotic-targeted eradication of specific oral pathogens hold potential to prevent IBD recurrence.

Correlation between Alzheimer's Disease and Gastrointestinal Tract Disorders

Alzheimer's disease is the most common cause of dementia globally. The pathogenesis is multifactorial and includes deposition of amyloid-β in the central nervous system, presence of intraneuronal neurofibrillary tangles and a decreased amount of synapses. It remains uncertain what causes the progression of the disease. Nowadays, it is suggested that the brain is connected to the gastrointestinal tract, especially the enteric nervous system and gut microbiome. Studies have found a positive association between AD and gastrointestinal diseases such as periodontitis, Helicobacter pylori infection, inflammatory bowel disease and microbiome disorders. H. pylori and its metabolites can enter the CNS via the oropharyngeal olfactory pathway and may predispose to the onset and progression of AD. Periodontitis may cause systemic inflammation of low severity with high levels of pro-inflammatory cytokines and neutrophils. Moreover, lipopolysaccharide from oral bacteria accompanies beta-amyloid in plaques that form in the brain. Increased intestinal permeability in IBS leads to neuronal inflammation from transference. Chronic inflammation may lead to beta-amyloid plaque formation in the intestinal tract that spreads to the brain via the vagus nerve. The microbiome plays an important role in many bodily functions, such as nutrient absorption and vitamin production, but it is also an important factor in the development of many diseases, including Alzheimer's disease. Both the quantity and diversity of the microbiome change significantly in patients with AD and even in people in the preclinical stage of the disease, when symptoms are not yet present. The microbiome influences the functioning of the central nervous system through, among other things, the microbiota-gut-brain axis. Given the involvement of the microbiome in the pathogenesis of AD, antibiotic therapy, probiotics and prebiotics, and faecal transplantation are being considered as possible therapeutic options.

Nanoarchitectonics-Based Materials as a Promising Strategy in the Treatment of Endodontic Infections

Endodontic infections arise from the interactive activities of microbial communities colonizing in the intricate root canal system. The present study aims to update the latest knowledge of nanomaterials, their antimicrobial mechanisms, and their applications in endodontics. A detailed literature review of the current knowledge of nanomaterials used in endodontic applications was performed using the PubMed database. Antimicrobial nanomaterials with a small size, large specific surface area, and high chemical activity are introduced to act as irrigants, photosensitizer delivery systems, and medicaments, or to modify sealers. The application of nanomaterials in the endodontic field could enhance antimicrobial efficiency, increase dentin tubule penetration, and improve treatment outcomes. This study supports the potential of nanomaterials as a promising strategy in treating endodontic infections.

Biology of tongue coating in different disease stages of RA and its value in disease progression

OBJECTIVE

To assess and compare the composition of tongue coating microbiota among patients at different stages of rheumatoid arthritis (RA).

METHODS

A total of 47 patients diagnosed with RA, as per the American College of Rheumatology criteria, and 10 healthy individuals were enrolled in this study. The RA patients were stratified considering their Disease Activity Score 28 (DAS28), a composite measure based on the 28 tender and swollen joint count and erythrocyte sedimentation rate (ESR). The study population was further categorized into active phase group (LMH group) and inactive phase group (RE group) according to their DAS28 values. DNA extraction was extracted from tongue coating samples. Subsequently, the V3-V4 16S rDNA region was selectively amplified and sequenced through high-throughput 16S rDNA analysis. The resulting data were then utilized to ascertain the microbial contents.

RESULTS

Significant variations were observed in the tongue coating microbiota of patients with RA during active and inactive phases, in comparison to healthy individuals (p < 0.05). At the genus level, the presence of Prevotellan, Veillonella, Rothia, and Neisseria in RA patients was notably more evident than in the healthy control (HC) group. These disparities find support in existing research on gut and oral microbiota. During the active phase of RA, the relative abundance of Veillonella, Rothia, and Neisseria in the tongue coating microbiota of patients was significantly higher than in those with inactive RA. These findings underscore the need for further and in-depth research on the potential impact of these microorganisms on the progression of RA disease.

CONCLUSION

The results substantiate the hypothesis that tongue coating microbes actively contribute to the progression of RA.

Uncovering the characteristics of the gut microbiota in patients with ischemic stroke and hemorrhagic stroke

This study aimed to explore the gut microbiota characteristics of ischemic and hemorrhagic stroke patients. A case-control study was conducted, and high-throughput sequencing of the V4-V5 region of 16S rRNA was used to analyze the differences in gut microbiota. The results showed that Proteobacteria was significantly increased in the ischemic stroke group compared with the healthy control group, while Fusobacteria was significantly increased in the hemorrhagic stroke group. In the ischemic stroke group, Butyricimonas, Alloprevotella, and Escherichia were significantly more abundant than in the healthy control group. In the hemorrhagic stroke group, Atopobium, Hungatella, Eisenbergiella, Butyricimonas, Odonbacter, Lachnociostridium, Alistipes, Parabacteroides, and Fusobacterium were significantly more abundant than in the healthy control group. Additionally, Alloprevotella, Ruminococcus, and Prevotella were significantly more abundant in the ischemic stroke group than in the hemorrhagic stroke group. The gut microbiota of ischemic and hemorrhagic stroke patients has significant diversity characteristics. These results provide new theoretical basis for exploring the prevention and treatment of different types of stroke through gut microbiota research.

Coaggregated E. faecalis with F. nucleatum regulated environmental stress responses and inflammatory effects

To investigate the cell-cell interactions of intergeneric bacterial species, the study detected the survival of Enterococcus faecalis (Ef) under monospecies or coaggregation state with Fusobacterium nucleatum subsp. polymorphum (Fnp) in environmental stress. Ef and Fnp infected the human macrophages with different forms (Ef and Fnp monospecies, Ef-Fnp coaggregates, Ef + Fnp cocultures) for exploring the immunoregulatory effects and the relevant molecular mechanisms. Meanwhile, the transcriptomic profiles of coaggregated Ef and Fnp were analyzed. Ef was shown to coaggregate with Fnp strongly in CAB within 90 min by forming multiplexes clumps. Coaggregation with Fnp reinforced Ef resistance against unfavorable conditions including alkaline, hypertonic, nutrient-starvation, and antibiotic challenges. Compared with monospecies and coculture species, the coaggregation of Ef and Fnp significantly facilitates both species to invade dTHP-1 cells and aid Ef to survive within the cells. Compared with coculture species, dual-species interaction of Ef and Fnp significantly decreased the levels of pro-inflammatory cytokines IL-6, TNF-α, and chemokines MCP-1 secreted by dTHP-1 cells and lessened the phosphorylation of p38, JNK, and p65 signaling pathways. The transcriptome sequencing results showed that 111 genes were differentially expressed or Ef-Fnp coaggregated species compared to Ef monospecies; 651 genes were differentially expressed for Fnp when coaggregation with Ef. The analysis of KEGG pathway showed that Ef differentially expressed genes (DEGs) were enriched in quorum sensing and arginine biosynthesis pathway; Fnp DEGs were differentially concentrated in lipopolysaccharide (LPS) biosynthesis, biofilm formation, and lysine degradation pathway compared to monospecies. KEY POINTS: • Coaggregated with Fnp aids Ef's survival in environmental stress, especially in root canals after endodontic treatment. • The coaggregation of Ef and Fnp may weaken the pro-inflammatory response and facilitate Ef to evade killed by macrophages. • The coaggregation between Ef and Fnp altered interspecies transcriptional profiles.

Characterization of tongue coating microbiome from patients with colorectal cancer

Background

Tongue coating microbiota has aroused particular interest in profiling oral and digestive system cancers. However, little is known on the relationship between tongue coating microbiome and colorectal cancer (CRC).

Methods

Metagenomic shotgun sequencing was performed on tongue coating samples collected from 30 patients with CRC, 30 patients with colorectal polyps (CP), and 30 healthy controls (HC). We further validated the potential of the tongue coating microbiota to predict the CRC by a random forest model.

Results

We found a greater species diversity in CRC samples, and the nucleoside and nucleotide biosynthesis pathway was more apparent in the CRC group. Importantly, various species across participants jointly shaped three distinguishable fur types.The tongue coating microbiome profiling data gave an area under the receiver operating characteristic curve (AUC) of 0.915 in discriminating CRC patients from control participants; species such as Atopobium rimae, Streptococcus sanguinis, and Prevotella oris aided differentiation of CRC patients from healthy participants.

Conclusion

These results elucidate the use of tongue coating microbiome in CRC patients firstly, and the fur-types observed contribute to a better understanding of the microbial community in human. Furthermore, the tongue coating microbiota-based biomarkers provide a valuable reference for CRC prediction and diagnosis.

Fusobacterium nucleatum: An Overview of Evidence, Demi-Decadal Trends, and Its Role in Adverse Pregnancy Outcomes and Various Gynecological Diseases, including Cancers

Gynecological and obstetric infectious diseases are crucial to women's health. There is growing evidence that links the presence of Fusobacterium nucleatum (F. nucleatum), an anaerobic oral commensal and potential periodontal pathogen, to the development and progression of various human diseases, including cancers. While the role of this opportunistic oral pathogen has been extensively studied in colorectal cancer in recent years, research on its epidemiological evidence and mechanistic link to gynecological diseases (GDs) is still ongoing. Thus, the present review, which is the first of its kind, aims to undertake a comprehensive and critical reappraisal of F. nucleatum, including the genetics and mechanistic role in promoting adverse pregnancy outcomes (APOs) and various GDs, including cancers. Additionally, this review discusses new conceptual advances that link the immunomodulatory role of F. nucleatum to the development and progression of breast, ovarian, endometrial, and cervical carcinomas through the activation of various direct and indirect signaling pathways. However, further studies are needed to explore and elucidate the highly dynamic process of host-F. nucleatum interactions and discover new pathways, which will pave the way for the development of better preventive and therapeutic strategies against this pathobiont.

Oral Microbially-Induced Small Extracellular Vesicles Cross the Blood-Brain Barrier

Porphyromonas gingivalis (Pg) and its gingipain proteases contribute to Alzheimer's disease (AD) pathogenesis through yet unclear mechanisms. Cellular secretion of small extracellular vesicles or exosomes (EXO) increases with aging as part of the senescence-associated secretory phenotype (SASP). We have shown that EXO isolated from Pg-infected dendritic cells contain gingipains and other Pg antigens and transmit senescence to bystander gingival cells, inducing alveolar bone loss in mice in vivo. Here, EXO were isolated from the gingiva of mice and humans with/without periodontitis (PD) to determine their ability to penetrate the blood-brain barrier (BBB) in vitro and in vivo. PD was induced by Pg oral gavage for 6 weeks in C57B6 mice. EXO isolated from the gingiva or brain of donor Pg-infected (PD EXO) or control animals (Con EXO) were characterized by NTA, Western blot, and TEM. Gingival PD EXO or Con EXO were labeled and injected into the gingiva of uninfected WT mouse model. EXO biodistribution in brains was tracked by an in vivo imaging system (IVIS) and confocal microscopy. The effect of human PD EXO on BBB integrity and permeability was examined using TEER and FITC dextran assays in a human in vitro 3D model of the BBB. Pg antigens (RGP and Mfa-1) were detected in EXO derived from gingival and brain tissues of donor Pg-infected mice. Orally injected PD EXO from donor mice penetrated the brains of recipient uninfected mice and colocalized with hippocampal microglial cells. IL-1β and IL-6 were expressed in human PD EXO and not in Con EXO. Human PD EXO promoted BBB permeability and penetrated the BBB in vitro. This is the first demonstration that microbial-induced EXO in the oral cavity can disseminate, cross the BBB, and may contribute to AD pathogenesis.

Screening inhibitors against the Ef-Tu of Fusobacterium nucleatum: a docking, ADMET and PBPK assessment study

The oral pathogen Fusobacterium nucleatum has recently been associated with an elevated risk of colorectal cancer (CRC), endometrial metastasis, chemoresistance, inflammation, metastasis, and DNA damage, along with several other diseases. This study aimed to explore the disruption of protein machinery of F. nucleatum via inhibition of elongation factor thermo unstable (Ef-Tu) protein, through natural products. No study on Ef-Tu inhibition by natural products or in Fusobacterium spp. exists till todate. Ef-Tu is an abundant specialized drug target in bacteria that varies from human Ef-Tu. Elfamycins target Ef-Tu and hence, Enacyloxin IIa was used to generate pharmacophore for virtual screening of three natural product libraries, Natural Product Activity and Species Source (NPASS) (n = 30000 molecules), Tibetan medicinal plant database (n = 54 molecules) and African medicinal plant database (n > 6000 molecules). Peptaibol Septocylindrin B (NPC141050), Hirtusneanoside, and ZINC95486259 were prioritized from these libraries as potential therapeutic candidates. ADMET profiling was done for safety assessment, physiological-based pharmacokinetic modeling in human and mouse for getting insight into drug interaction with body tissues and molecular dynamics was used to assess stability of the best hit NPC141050 (Septocylindrin B). Based on the promising results, we propose further in vitro, in vivo and pharmacokinetic testing on the lead Septocylindrin B, for possible translation into therapeutic interventions.

The ways Fusobacterium nucleatum translocate to breast tissue and contribute to breast cancer development

Breast cancer is among the most prevalent malignancies in women worldwide. Epidemiological findings suggested that periodontal diseases may be associated with breast cancer, among which Fusobacterium nucleatum is considered an important cross-participant. In this work, we comprehensively summarize the known mechanisms of how F. nucleatum translocates to, colonizes in mammary tumors, and promotes the carcinogenesis. Specifically, F. nucleatum translocates to mammary tissue through the mammary-intestinal axis, direct nipple contact, and hematogenous transmission. Subsequently, F. nucleatum takes advantage of fusobacterium autotransporter protein 2 to colonize breast cancer and uses virulence factors fusobacterium adhesin A and lipopolysaccharide to promote proliferation. Moreover, the upregulated matrix metalloproteinase-9 induced by F. nucleatum does not only trigger the inflammatory response but also facilitates the tumor-promoting microenvironment. Aside from the pro-inflammatory effect, F. nucleatum may also be engaged in tumor immune evasion, which is achieved through the action of virulence factors on immune checkpoint receptors highly expressed on T cells, natural killer cells, and tumor-infiltrating lymphocytes. Taking breast cancer as an example, more relevant research studies may expand our current knowledge of how oral microbes affect systemic health. Hopefully, exploring these mechanisms in depth could provide new strategies for safer and more effective biologic and targeted therapies targeted at breast cancer.

Molecular commensalism-how to investigate underappreciated health-associated polymicrobial communities

The study of human commensal bacteria began with the first observation of prokaryotes >340 years ago. Since then, the study of human-associated microbes has been justifiably biased toward the study of infectious pathogens. However, the role of commensal microbes has in recent years begun to be understood with some appreciation of them as potential protectors of host health rather than bystanders. As our understanding of these valuable microbes grows, it highlights how much more remains to be learned about them and their roles in maintaining health. We note here that a thorough framework for the study of commensals, both in vivo and in vitro is overall lacking compared to well-developed methodologies for pathogens. The modification and application of methods for the study of pathogens can work well for the study of commensals but is not alone sufficient to properly characterize their relationships. This is because commensals live in homeostasis with the host and within complex communities. One difficulty is determining which commensals have a quantifiable impact on community structure and stability as well as host health, vs benign microbes that may indeed serve only as bystanders. Human microbiomes are composed of bacteria, archaea, fungi, and viruses. This review focuses particularly on oral bacteria, yet many of the principles of commensal impacts on host health observed in the mouth can translate well to other host sites. Here, we discuss the value of commensals, the shortcomings involved in model systems for their study, and some of the more notable impacts they have upon not only each other but host health.

The prevalence of Fusobacterium nucleatum subspecies in the oral cavity stratifies by local health status

The ubiquitous inflammophilic pathobiont Fusobacterium nucleatum is widely recognized for its strong association with a variety of human dysbiotic diseases such as periodontitis and oral/extraoral abscesses, as well as multiple types of cancer. F. nucleatum is currently subdivided into four subspecies: F. nucleatum subspecies nucleatum (Fn. nucleatum), animalis (Fn. animalis), polymorphum (Fn. polymorphum), and vincentii/fusiforme (Fn. vincentii). Although these subspecies have been historically considered as functionally interchangeable in the oral cavity, direct clinical evidence is largely lacking for this assertion. Consequently, we assembled a collection of oral clinical specimens to determine whether F. nucleatum subspecies prevalence in the oral cavity stratifies by local oral health status. Patient-matched clinical specimens of both disease-free dental plaque and odontogenic abscess were analyzed with newly developed culture-dependent and culture-independent approaches using 44 and 60 oral biofilm/tooth abscess paired specimens, respectively. Most oral cavities were found to simultaneously harbor multiple F. nucleatum subspecies, with a greater diversity present within dental plaque compared to abscesses. In dental plaque, Fn. polymorphum is clearly the dominant organism, but this changes dramatically within odontogenic abscesses where Fn. animalis is heavily favored over all other fusobacteria. Surprisingly, the most commonly studied F. nucleatum subspecies, Fn. nucleatum, is only a minor constituent in the oral cavity. To gain further insights into the genetic basis for these phenotypes, we subsequently performed pangenome, phylogenetic, and functional enrichment analyses of oral fusobacterial genomes using the Anvi'o platform, which revealed significant genotypic distinctions among F. nucleatum subspecies. Accordingly, our results strongly support a taxonomic reassignment of each F. nucleatum subspecies into distinct Fusobacterium species. Of these, Fn. animalis should be considered as the most clinically relevant at sites of active inflammation, despite being among the least characterized oral fusobacteria.

The Complicated Relationship of Short-Chain Fatty Acids and Oral Microbiome: A Narrative Review

The human oral microbiome has emerged as a focal point of research due to its profound implications for human health. The involvement of short-chain fatty acids in oral microbiome composition, oral health, and chronic inflammation is gaining increasing attention. In this narrative review, the results of early in vitro, in vivo, and pilot clinical studies and research projects are presented in order to define the boundaries of this new complicated issue. According to the results, the current research data are disputable and ambiguous. When investigating the role of SCFAs in human health and disease, it is crucial to distinguish between their local GI effects and the systemic influences. Locally, SCFAs are a part of normal oral microbiota metabolism, but the increased formation of SCFAs usually attribute to dysbiosis; excess SCFAs participate in the development of local oral diseases and in oral biota gut colonization and dysbiosis. On the other hand, a number of studies have established the positive impact of SCFAs on human health as a whole, including the reduction of chronic systemic inflammation, improvement of metabolic processes, and decrease of some types of cancer incidence. Thus, a complex and sophisticated approach with consideration of origin and localization for SCFA function assessment is demanded. Therefore, more research, especially clinical research, is needed to investigate the complicated relationship of SCFAs with health and disease and their potential role in prevention and treatment.

The Role of Fusobacterium nucleatum in Oral and Colorectal Carcinogenesis

In recent years, several studies have suggested a strong association of microorganisms with several human cancers. Two periodontopathogenic species in particular have been mentioned frequently: Fusobacterium nucleatum (F. nucleatum) and Porphyromonas gingivalis. Chronic periodontal disease has been reported to be a risk factor for oral squamous cell carcinoma (OSCC), colorectal cancer (CRC) and pancreatic cancer. F. nucleatum is a Gram-negative anaerobic bacterium that lives in the oral cavity, urogenital, intestinal and upper digestive tract. It plays a significant role as a co-aggregation factor, with almost all bacterial species that participate in oral plaque formation acting as a bridge between early and late colonizers. F. nucleatum, gives an important inflammatory contribution to tumorigenesis progression and is associated with epithelial-derived malignancies, such as OSCC and CRC. F. nucleatum produces an adhesion protein, FadA, which binds to VE-cadherin on endothelial cells and to E-cadherins on epithelial cells. The last binding activates oncogenic pathways, such as Wnt/βcatenin, in oral and colorectal carcinogenesis. F. nucleatum also affects immune response because its Fap2 protein interacts with an immune receptor named TIGIT present on some T cells and natural killer cells inhibiting immune cells activities. Morover, F. nucleatum release outer membrane vesicles (OMVs), which induce the production of proinflammatory cytokines and initiating inflammation. F. nucleatum migrates from the oral cavity and reaches the colon hematogenously but it is not known if in the bloodstream it reaches the CRC as free, erythrocyte-bound bacteria or in OMV. F. nucleatum abundance in CRC tissue has been inversely correlated with overall survival (OS). The prevention and treatment of periodontal disease through the improvement of oral hygiene should be included in cancer prevention protocols. FadA virulence factors may also serve as novel targets for therapeutic intervention of oral and colorectal cancer.

Personalized Medicine in Oral Oncology: Imaging Methods and Biological Markers to Support Diagnosis of Oral Squamous Cell Carcinoma (OSCC): A Narrative Literature Review

For decades, oral squamous cell carcinoma (OSCC) has been one of the most prevalent and mortal cancers worldwide. The gold standard for OSCC diagnosis is still histopathology but this narrative multidisciplinary review has the aim to explore the literature about conventional OSCC prognostic indicators related to the pTNM stage at the diagnosis such as the depth of invasion and the lymphovascular invasion associated with distant metastasis as indicators of poor life expectancy. Despite its multifactorial nature and recognizable precursors, its diagnosis at the early stages is still challenging. We wanted to highlight the importance of the screening as a primary weapon that a stomatologist should consider, intercepting all at-risk conditions and lesions associated with OSCC and its early stages. This narrative review also overviews the most promising imaging techniques, such as CT, MRI, and US-echography, and their application related to clinical and surgical practice, but also the most-investigated prognostic and diagnostic tissue and salivary biomarkers helpful in OSCC diagnosis and prognostic assessment. Our work highlighted remarkable potential biomarkers that could have a leading role in the future. However, we are still far from defining an appropriate and concrete protocol to apply in clinical practice. The hope is that the present and future research will overcome these limitations to benefit patients, clinicians, and welfare.

Comparative genomic analysis of Fusobacterium nucleatum reveals high intra-species diversity and cgmlst marker construction

BACKGROUND

Fusobacterium nucleatum is a one of the most important anaerobic opportunistic pathogens in the oral and intestinal tracts of human and animals. It can cause various diseases such as infections, Lemierre's syndrome, oral cancer and colorectal cancer. The comparative genomic studies on the population genome level, have not been reported.

RESULTS

We analyzed all publicly available Fusobacterium nucleatums' genomic data for a comparative genomic study, focusing on the pan-genomic features, virulence genes, plasmid genomes and developed cgmlst molecular markers. We found the pan-genome shows a clear open tendency and most of plasmids in Fusobacterium nucleatum are mainly transmitted intraspecifically.

CONCLUSIONS

Our comparative analysis of Fusobacterium nucleatum systematically revealed the open pan-genomic features and phylogenetic tree based on cgmlst molecular markers. What's more, we also identified common plasmid typing among genomes. We hope that our study will provide a theoretical basis for subsequent functional studies.

Periodontopathogens Porphyromonas gingivalis and Fusobacterium nucleatum and Their Roles in the Progression of Respiratory Diseases

The intricate interplay between oral microbiota and the human host extends beyond the confines of the oral cavity, profoundly impacting the general health status. Both periodontal diseases and respiratory diseases show high prevalence worldwide and have a marked influence on the quality of life for the patients. Accumulating studies are establishing a compelling association between periodontal diseases and respiratory diseases. Here, in this review, we specifically focus on the key periodontal pathogenic bacteria Porphyromonas gingivalis and Fusobacterium nucleatum and dissect their roles in the onset and course of respiratory diseases, mainly pneumonia, chronic obstructive pulmonary disease, lung cancer, and asthma. The mechanistic underpinnings and molecular processes on how P. gingivalis and F. nucleatum contribute to the progression of related respiratory diseases are further summarized and analyzed, including: induction of mucus hypersecretion and chronic airway inflammation; cytotoxic effects to disrupt the morphology and function of respiratory epithelial cells; synergistic pathogenic effects with respiratory pathogens like Streptococcus pneumoniae and Pseudomonas aeruginosa. By delving into the complex relationship to periodontal diseases and periodontopathogens, this review helps unearth novel insights into the etiopathogenesis of respiratory diseases and inspires the development of potential therapeutic avenues and preventive strategies.

The Roles of Periodontal Bacteria in Atherosclerosis

Atherosclerosis (AS) is an inflammatory vascular disease that constitutes a major underlying cause of cardiovascular diseases (CVD) and stroke. Infection is a contributing risk factor for AS. Epidemiological evidence has implicated individuals afflicted by periodontitis displaying an increased susceptibility to AS and CVD. This review concisely outlines several prevalent periodontal pathogens identified within atherosclerotic plaques, including Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum. We review the existing epidemiological evidence elucidating the association between these pathogens and AS-related diseases, and the diverse mechanisms for which these pathogens may engage in AS, such as endothelial barrier disruption, immune system activation, facilitation of monocyte adhesion and aggregation, and promotion of foam cell formation, all of which contribute to the progression and destabilization of atherosclerotic plaques. Notably, the intricate interplay among bacteria underscores the complex impact of periodontitis on AS. In conclusion, advancing our understanding of the relationship between periodontal pathogens and AS will undoubtedly offer invaluable insights and potential therapeutic avenues for the prevention and management of AS.

Probing antibacterial drugs for Fusobacterium nucleatum subsp. nucleatum ATCC 25586 targeting UDP-N-acetylglucosamine 1-carboxyltransferase

Fusobacterium nucleatum is a Gram-negative anaerobic bacteria that is commonly found in oral cavities and is associated with connective tissue destruction in periodontitis. UDP-N-acetylglucosamine 1-carboxyltransferase with enzyme commission number 2.5.1.7 is a transferases enzyme that plays a role in bacterial pathogenesis. Inhibiting binding sites of UDP-N-acetylglucosamine 1-carboxyltransferase is needed to find potential antibiotic candidates for periodontitis treatment. Hence, the research aimed to present potential UDP-N-acetylglucosamine 1-carboxyltransferase inhibiting compounds through molecular docking simulation by in silico analysis. DrugBank database was used to obtain the antibacterial candidates, which were further screened computationally using the AutoDock Vina program on Google Colab Pro. The top nine compounds yielded binding affinity ranging from -12.1 to -12.8 kcal/mol, with conivaptan as one of the three compounds having the highest binding affinity. Molecular dynamic study revealed that the ligand-protein complex for conivaptan had root-mean-square deviation values of 0.05-1.1 nm, indicating likeliness for stable interaction. Our findings suggest that conivaptan is the potent UDP-N-acetylglucosamine 1-carboxyltransferase inhibitor, hence its efficacy against periodontitis-causing bacteria.