Fusobacterium nucleatum impedes remission of colitis in a mouse model

Regulation of Gut Microbiota and Microbial Metabolome of Kefir Supernatant against Fusobacterium nucleatum and DSS-Coinduced Colitis

The aim of this study was to investigate the intervention effect of kefir supernatant (KS) on the initiation and progression of an ulcerative colitis (UC) murine model. We established an UC murine model by orally administrating with 109 CFUs of Fusobacterium nucleatum for 3 weeks and 3% dextran sulfate sodium (DSS) treatment in the third week. KS was used to intervene in this colitis model. Our results showed that KS supplementation ameliorated the symptoms, restrained the secretion of pro-inflammatory cytokines (TNF-α, IL-6, and IL-17F), promoted the release of anti-inflammatory cytokines (IL-4 and IL-10), and ameliorated oxidative stress. Furthermore, the increased number of goblet cells and upregulated expression of MUC2, occludin and claudin-1 indicated that the colon barrier was protected by KS. Additionally, KS supplementation mitigated gut microbiota dysbiosis in the UC murine model, leading to an increase in the abundance of Blautia and Akkermansia and a decrease in the level of Bacteroides. The altered gut microbiota also affected colon metabolism, with differential metabolites mainly associated with the biosynthesis of the l-arginine pathway. This study revealed that KS supplementation restored the community structure of gut microbiota, altered the biosynthesis of l-arginine, and thereby modulated the process of colonic inflammation.

Lactobacillus plantarum surface-displayed FomA (Fusobacterium nucleatum) protein generally stimulates protective immune responses in mice

A significant correlation is observed between Fusobacterium nucleatum (F. nucleatum) and the evolution of inflammatory bowel disease (IBD). Particularly, FomA, a critical pathogenic element of F. nucleatum, inflicts substantial detriment to human intestinal health. Our research focused on the development of recombinant Lactobacillus plantarum that expresses FomA protein, demonstrating its potential in protecting mice from severe IBD induced by F. nucleatum. To commence, two recombinant strains, namely L. plantarum NC8-pSIP409-pgsA'-FomA and NC8-pSIP409-FnBPA-pgsA'-FomA, were successfully developed. Validation of the results was achieved through flow cytometry, ELISA, and MTT assays. It was observed that recombinant L. plantarum instigated mouse-specific humoral immunity and elicited mucosal and T cell-mediated immune responses. Significantly, it amplified the immune reaction of B cells and CD4+T cells, facilitated the secretion of cytokines such as IgA, IL4, and IL10, and induced lymphocyte proliferation in response to FomA protein stimulation. Finally, we discovered that administering recombinant L. plantarum could protect mice from severe IBD triggered by F. nucleatum, subsequently reducing pathological alterations and inflammatory responses. These empirical findings further the study of an innovative oral recombinant Lactobacillus vaccine.

Characterization of Maladaptive Processes in Acute, Chronic and Remission Phases of Experimental Colitis in C57BL/6 Mice

Inflammatory bowel disease (IBD) is a chronic recurrent inflammatory disease with unknown etiology. Dextran sulfate sodium (DSS) induced colitis is a widely used mouse model in IBD research. DSS colitis involves activation of the submucosal immune system and can be used to study IBD-like disease characteristics in acute, chronic, remission and transition phases. Insight into colon inflammatory parameters is needed to understand potentially irreversible adaptations to the chronification of colitis, determining the baseline and impact of further inflammatory episodes. We performed analyses of non-invasive and invasive colitis parameters in acute, chronic and remission phases of the DSS colitis in C57BL/6 mice. Non-invasive colitis parameters poorly reflected inflammatory aspects of colitis in chronic remission phase. We found invasive inflammatory parameters, positively linked to repeated DSS-episodes, such as specific colon weight, inflamed colon area, spleen weight, absolute cell numbers of CD4+ and CD8+ T cells as well as B cells, blood IFN-γ level, colonic chemokines BLC and MDC as well as the prevalence of Turicibacter species in feces. Moreover, microbial Lactobacillus species decreased with chronification of disease. Our data point out indicative parameters of recurrent gut inflammation in context of DSS colitis.

Ulcerative Colitis Seems to Imply Oral Microbiome Dysbiosis

Ulcerative colitis (UC) is a recurrent pathology of complex etiology that has been occasionally associated with oral lesions, but the overall composition of the oral microbiome in UC patients and its role in the pathogenesis of the disease are still poorly understood. In this study, the oral microbiome of UC patients and healthy individuals was compared to ascertain the possible changes in the oral microbial communities associated with UC. For this, the salivary microbiota of 10 patients diagnosed with an active phase of UC and 11 healthy controls was analyzed by 16S rRNA gene sequencing (trial ref. ISRCTN39987). Metataxonomic analysis revealed a decrease in the alpha diversity and an imbalance in the relative proportions of some key members of the oral core microbiome in UC patients. Additionally, Staphylococcus members and four differential species or phylotypes were only present in UC patients, not being detected in healthy subjects. This study provides a global snapshot of the existence of oral dysbiosis associated with UC, and the possible presence of potential oral biomarkers.

Oral microbiota in human systematic diseases

Oral bacteria directly affect the disease status of dental caries and periodontal diseases. The dynamic oral microbiota cooperates with the host to reflect the information and status of immunity and metabolism through two-way communication along the oral cavity and the systemic organs. The oral cavity is one of the most important interaction windows between the human body and the environment. The microenvironment at different sites in the oral cavity has different microbial compositions and is regulated by complex signaling, hosts, and external environmental factors. These processes may affect or reflect human health because certain health states seem to be related to the composition of oral bacteria, and the destruction of the microbial community is related to systemic diseases. In this review, we discussed emerging and exciting evidence of complex and important connections between the oral microbes and multiple human systemic diseases, and the possible contribution of the oral microorganisms to systemic diseases. This review aims to enhance the interest to oral microbes on the whole human body, and also improve clinician’s understanding of the role of oral microbes in systemic diseases. Microbial research in dentistry potentially enhances our knowledge of the pathogenic mechanisms of oral diseases, and at the same time, continuous advances in this frontier field may lead to a tangible impact on human health.

Pine (Pinus massoniana Lamb.) Needle Extract Supplementation Improves Performance, Egg Quality, Serum Parameters, and the Gut Microbiome in Laying Hens

The effects of Masson pine (Pinus massoniana Lamb.) needle extract (PNE) on gastrointestinal disorders and oxidative stress have been widely investigated using experimental models; however, the functions and mechanisms of these effects in chicken models remain unknown. We investigated the effects of Masson PNE supplementation on performance, egg quality, serum parameters, and the gut microbiome in laying hens. A total of 60 healthy 50-week-old Peking Pink laying hens with similar body conditions and egg production were randomly divided into the control (CON) (0 mg/kg PNE), PNE100 (100 mg/kg PNE), PNE200 (200 mg/kg PNE), and PNE400 (400 mg/kg PNE) groups, with fifteen replicates per treatment and one hen per replicate. Compared with the CON group, egg mass, feed conversion ratios, and yolk weight were significantly increased (p < 0.01) in the PNE100 group. Dietary supplementation of 100 mg/kg PNE increased the serum total protein, albumin, and glucose concentrations (p < 0.01) and decreased the alanine aminotransferase activity (p < 0.05) compared with those of the CONs. Hens in the PNE100 group had reduced serum malondialdehyde levels (p < 0.05) and increased catalase, superoxide dismutase, and glutathione peroxidase activities (p < 0.01) compared with those of the CON group. Serum proinflammatory cytokine concentrations of interleukin (IL)-1β, IL-6, and tumor necrosis factor-α were lower (p < 0.01) and the IL-10 level was higher (p < 0.01) in the PNE100 group than in the CON group. Serum immunoglobulin (Ig)A, IgG, and IgM concentrations were increased in the PNE100 group (p < 0.01). The relative abundance of Bacteroidetes was increased, while the relative abundances of Firmicutes and Proteobacteria were decreased in the PNE100 group. The relative abundances of Vibrio, Shewanella, and Lactobacillus were decreased, while the relative abundances of unclassified_o_Bacteroidales, Rikenellaceae_RC9_gut_group, unclassified_f_Rikenellaceae, and Butyricicoccaceae were increased in the PNE100 group compared with those of the CON group. PNE supplementation at 100 mg/kg improved the diversity and structure of the gut microbial composition, production performance, egg quality, and serum parameters of laying hens. The laying hens in this study had good production performance when supplemented with 100 mg/kg PNE.