Fusobacterium nucleatum mediates endothelial damage and increased permeability following single species and polymicrobial infection

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 exoprotein Gbp of Fusobacterium nucleatum promotes THP-1 cell lipid deposition by binding to CypA and activating PI3K-AKT/MAPK/NF-κB pathways

INTRODUCTION

Growing evidence has shown the correlation between periodontitis and atherosclerosis, while our knowledge on the pathogenesis of periodontitis-promoting atherosclerosis is far from sufficient.

OBJECTIVES

Illuminate the pathogenic effects of Fusobacterium nucleatum (F. nucleatum) on intracellular lipid deposition in THP-1-derived macrophages and elucidate the underlying pathogenic mechanism of how F. nucleatum promoting atherosclerosis.

METHODS AND RESULTS

F. nucleatum was frequently detected in different kinds of atherosclerotic plaques and its abundance was positively correlated with the proportion of macrophages. In vitro assays showed F. nucleatum could adhere to and invade THP-1 cells, and survive continuously in macrophages for 24 h. F. nucleatum stimulation alone could significantly promote cellular inflammation, lipid uptake and inhibit lipid outflow. The dynamic gene expression of THP-1 cells demonstrated that F. nucleatum could time-serially induce the over-expression of multiple inflammatory related genes and activate NF-κB, MAPK and PI3K-AKT signaling pathways. The exoprotein of F. nucleatum, D-galactose-binding protein (Gbp), acted as one of the main pathogenic proteins to interact with the Cyclophilin A (CypA) of THP-1 cells and induced the activation of the NF- κB, MAPK and PI3K-AKT signaling pathways. Furthermore, use of six candidate drugs targeting to the key proteins in NF- κB, MAPK and PI3K-AKT pathways could dramatically decrease F. nucleatum induced inflammation and lipid deposition in THP-1 cells.

CONCLUSIONS

This study suggests that the periodontal pathogen F. nucleatum can activate macrophage PI3K-AKT/MAPK/NF-κB signal pathways, promotes inflammation, enhances cholesterol uptake, reduces lipid excretion, and promotes lipid deposition, which may be one of its main strategies promoting the development of atherosclerosis.

Association between Periodontal Disease and Arteriosclerosis-Related Diseases

Periodontitis, a major inflammatory disease of the oral cavity that can cause low-grade systemic inflammation, has been suggested to influence the development of comorbidities. Multiple systemic inflammatory mechanisms are common in the development of periodontal disease and atherosclerosis. Observational studies conducted worldwide have reported that periodontal disease may independently influence the progression of atherosclerotic disease. However, there is still insufficient evidence to demonstrate the causal relationship. This review describes the association between periodontal disease and arteriosclerosis-related diseases with the latest findings.

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.

Colonization of Fusobacterium nucleatum is an independent predictor of poor prognosis in gastric cancer patients with venous thromboembolism: a retrospective cohort study

BACKGROUND

Fusobacterium nucleatum (F. nucleatum) often colonizes cancerous gastric tissues and is characterized by the promotion of platelet aggregation and the development of visceral thrombosis. Venous thromboembolism (VTE) leads to a significant increase in the mortality of gastric cancer (GC) patients. However, the relationship between the colonization of F. nucleatum and the prognosis of GC patients is still unknown.

AIM

The aim of this study was to explore whether the colonization of F. nucleatum is related to the prognosis of GC patients complicated with VTE and to explore other potential risk factors.

METHODS

From 2017-2021, the data of 304 patients with new VTEs during the treatment of GC at the Affiliated Cancer Hospital of Zhengzhou University were collected. Fluorescence in situ hybridization of F. nucleatum was performed on pathological sections of cancer tissues from the patients. Survival analysis methods, including the Kaplan‒Meier method and Cox proportional hazard model, were performed.

RESULTS

F. nucleatum colonization was significantly associated with splanchnic vein thrombosis, higher platelet-lymphocyte ratio (PLR), and lower absolute lymphocyte count. In the multivariable Cox model, F. nucleatum colonization was found to be an independent risk factor for the prognosis of GC, with an adjusted HR of 1.77 (95% CI, 1.17 to 2.69 [P = 0.007]). In addition, patients with high PLR (HR: 2.65, P = 0.004) or VTE occurring during four cycles of chemotherapy (HR: 2.32, P = 0.012) exhibited shorter survival. Conversely, those experiencing VTE later (HR per month from diagnosis of GC: 0.95, P = 0.006) or using IVC filters (HR: 0.27, P = 0.011) had longer survival.

CONCLUSION

Colonization of F. nucleatum in GC tissues was associated with lower absolute lymphocyte count and higher PLR in GC patients with VTE. F. nucleatum colonization also appeared to be associated with the development of VTE in specific sites, in particular the splanchnic vein. Colonization of F. nucleatum may potentially represent an independent predictor of poor prognosis in GC patients. Additional research is necessary to validate these findings.

Identification and characterization of non-coding RNA networks in infected macrophages revealing the pathogenesis of F. nucleatum-associated diseases

BACKGROUND

F. nucleatum, as an important periodontal pathogen, is not only closely associated with the development of periodontitis, but also implicated in systemic diseases. Macrophages may act as an important mediator in the pathogenic process of F. nucleatum infection. As non-coding RNAs (ncRNAs) have attracted extensive attention as important epigenetic regulatory mechanisms recently, we focus on the competing endogenous RNA (ceRNA) regulatory networks to elucidate the pathogenesis of F. nucleatum-associated diseases.

RESULTS

We screen abnormally expressed mRNAs, miRNAs, lncRNAs and circRNAs in macrophages after F. nucleatum infection via the whole transcriptome sequencing technology, including 375 mRNAs, 5 miRNAs, 64 lncRNAs, and 180 circRNAs. The accuracy of RNA-seq and microRNA-seq result was further verified by qRT-PCR analysis. GO and KEGG analysis show that the differentially expressed genes were mainly involved in MAPK pathway, Toll-like receptor pathway, NF-κB pathway and apoptosis. KEGG disease analysis reveals that they were closely involved in immune system diseases, cardiovascular disease, cancers, inflammatory bowel disease (IBD) et al. We constructed the underlying lncRNA/circRNA-miRNA-mRNA networks to understand their interaction based on the correlation analysis between the differentially expressed RNAs, and then screen the core non-coding RNAs. In which, AKT2 is controlled by hsa_circ_0078617, hsa_circ_0069227, hsa_circ_0084089, lncRNA NUP210, lncRNA ABCB9, lncRNA DIXDC1, lncRNA ATXN1 and lncRNA XLOC_237387 through miR-150-5p; hsa_circ_0001165, hsa_circ_0008460, hsa_circ_0001118, lncRNA XLOC_237387 and lncRNA ATXN1 were identified as the ceRNAs of hsa-miR-146a-3p and thereby indirectly modulating the expression of MITF.

CONCLUSIONS

Our data identified promising candidate ncRNAs responsible for regulating immune response in the F. nucleatum-associated diseases, offering new insights regarding the pathogenic mechanism of this pathogen.