Parabacteroides distasonis attenuates tumorigenesis, modulates inflammatory markers and promotes intestinal barrier integrity in azoxymethane-treated A/J mice

Aryl hydrocarbon receptor activity in intestinal epithelial cells in the formation of colonic tertiary lymphoid tissues

After birth, the development of secondary lymphoid tissues (SLTs) in the colon is dependent on the expression of the aryl hydrocarbon receptor (AhR) in immune cells as a response to the availability of AhR ligands. However, little is known about how AhR activity from intestinal epithelial cells (IECs) may influence the development of tertiary lymphoid tissues (TLTs). As organized structures that develop at sites of inflammation or infection during adulthood, TLTs serve as localized centers of adaptive immune responses, and their presence has been associated with the resolution of inflammation and tumorigenesis in the colon. Here, we investigated the effect of the conditional loss of AhR activity in IECs in the formation and immune cell composition of TLTs in a model of acute inflammation. In females, loss of AhR activity in IECs reduced the formation of TLTs without significantly changing disease outcomes or immune cell composition within TLTs. In males lacking AhR expression in IECs, increased disease activity index, lower expression of functional-IEC genes, increased number of TLTs, increased T-cell density, and lower B- to T-cell ratio were observed. These findings may represent an unfavorable prognosis when exposed to dextran sodium sulfate (DSS)-induced epithelial damage compared with females. Sex and loss of IEC AhR also resulted in changes in microbial populations in the gut. Collectively, these data suggest that the formation of TLTs in the colon is influenced by sex and AhR expression in IECs.NEW & NOTEWORTHY This is the first research of its kind to demonstrate a clear connection between biological sex and the development of tertiary lymphoid tissues (TLT) in the colon. In addition, the research finds that in a preclinical model of inflammatory bowel disease, the expression of the aryl hydrocarbon receptor (AhR) influences the development of these structures in a sex-specific manner.

Ningxiang Pig-Derived Parabacteroides distasonis HNAU0205 Alleviates ETEC-Induced Intestinal Apoptosis, Oxidative Damage, and Inflammation in Piglets

Weaning is a critical stage in the growth and development of piglets, often inducing stress reactions. This study aims to investigate the effects of Parabacteroides distasonis (PBd) derived from Ningxiang pigs on growth performance, intestinal apoptosis, oxidative damage, and inflammation in ETEC-challenged weaned piglets. A total of 22 Duroc × Landrace × Yorkshire (DLY) piglets, 24 days old with similar body weights, were randomly divided into three groups: Control (n = 7), ETEC (n = 7), and PBd + ETEC (n = 8). The results show that, compared to the Control group, ETEC challenge led to decreased growth performance, reduced villus height in the duodenum and jejunum, increased crypt depth in the duodenum, a decreased villus-height-to-crypt-depth ratio, increased expression of apoptosis-related genes (Caspase-8 and Caspase-9), increased expression of oxidative damage-related genes (Nrf2, GSH-PX, mTOR, and Beclin1), increased expression of inflammation-related genes (Myd88, P65, TNF-α, and IL-6), and reduced the contents of SCFAs in the colonic chyme (acetate, propionate, butyrate, valerate, and total SCFAs). Compared to the ETEC group, the PBd + ETEC group alleviated the reduction in growth performance, mitigated intestinal morphological damage, and reduced the expression of the aforementioned apoptosis, oxidative damage, and inflammation-related genes with the increase in SCFAs. In conclusion, PBd derived from Ningxiang pigs effectively reduces ETEC-induced intestinal damage in weaned piglets, improves intestinal health, and increases the content of SCFAs in the colonic chyme, thereby enhancing growth performance.

Parabacteroides distasonis regulates the infectivity and pathogenicity of SVCV at different water temperatures

BACKGROUND

Spring viremia of carp virus (SVCV) infects a wide range of fish species and causes high mortality rates in aquaculture. This viral infection is characterized by seasonal outbreaks that are temperature-dependent. However, the specific mechanism behind temperature-dependent SVCV infectivity and pathogenicity remains unclear. Given the high sensitivity of the composition of intestinal microbiota to temperature changes, it would be interesting to investigate if the intestinal microbiota of fish could play a role in modulating the infectivity of SVCV at different temperatures.

RESULTS

Our study found that significantly higher infectivity and pathogenicity of SVCV infection in zebrafish occurred at relatively lower temperature. Comparative analysis of the intestinal microbiota in zebrafish exposed to high- and low-temperature conditions revealed that temperature influenced the abundance and diversity of the intestinal microbiota in zebrafish. A significantly higher abundance of Parabacteroides distasonis and its metabolite secondary bile acid (deoxycholic acid, DCA) was detected in the intestine of zebrafish exposed to high temperature. Both colonization of Parabacteroides distasonis and feeding of DCA to zebrafish at low temperature significantly reduced the mortality caused by SVCV. An in vitro assay demonstrated that DCA could inhibit the assembly and release of SVCV. Notably, DCA also showed an inhibitory effect on the infectious hematopoietic necrosis virus, another Rhabdoviridae member known to be more infectious at low temperature.

CONCLUSIONS

This study provides evidence that temperature can be an important factor to influence the composition of intestinal microbiota in zebrafish, consequently impacting the infectivity and pathogenicity of SVCV. The findings highlight the enrichment of Parabacteroides distasonis and its derivative, DCA, in the intestines of zebrafish raised at high temperature, and they possess an important role in preventing the infection of SVCV and other Rhabdoviridae members in host fish. Video Abstract.

Complex insoluble dietary fiber alleviates obesity and liver steatosis, and modulates the gut microbiota in C57BL/6J mice fed a high-fat diet

BACKGROUND

Obesity has been demonstrated as a risk factor that seriously affects health. Insoluble dietary fiber (IDF), as a major component of dietary fiber, has positive effects on obesity, inflammation and diabetes.

RESULTS

In this study, complex IDF was prepared using 50% enoki mushroom IDF, 40% carrot IDF, and 10% oat IDF. The effects and potential mechanism of complex IDF on obesity were investigated in C57BL/6 mice fed a high-fat diet. The results showed that feeding diets containing 5% complex IDF for 8 weeks significantly reduced mouse body weight, epididymal lipid index, and ectopic fat deposition, and improved mouse liver lipotoxicity (reduced serum levels of alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase), fatty liver, and short-chain fatty acid composition. High-throughput sequencing of 16S rRNA and analysis of fecal metabolomics showed that the intervention with complex IDF reversed the high-fat-diet-induced dysbiosis of gut microbiota, which is associated with obesity and intestinal inflammation, and affected metabolic pathways, such as primary bile acid biosynthesis, related to fat digestion and absorption.

CONCLUSION

Composite IDF intervention can effectively inhibit high-fat-diet-induced obesity and related symptoms and affect the gut microbiota and related metabolic pathways in obesity. Complex IDF has potential value in the prevention of obesity and metabolic syndrome. © 2024 Society of Chemical Industry.

Exploring the Relationship between MicroRNAs, Intratumoral Microbiota, and Breast Cancer Progression in Patients with and without Metastasis

Breast cancer (BC) continues to pose a significant burden on global cancer-related morbidity and mortality, primarily driven by metastasis. However, the combined influence of microRNAs (miRNAs) and intratumoral microbiota on BC metastasis remains largely unexplored. In this study, we aimed to elucidate the interplay between intratumoral microbiota composition, miRNA expression profiles, and their collective influence on metastasis development in BC patients by employing 16S rRNA sequencing and qPCR methodologies. Our findings revealed an increase in the expression of miR-149-5p, miR-20b-5p, and miR-342-5p in metastatic breast cancer (Met-BC) patients. The Met-BC patients exhibited heightened microbial richness and diversity, primarily attributed to diverse pathogenic bacteria. Taxonomic analysis identified several pathogenic and pro-inflammatory species enriched in Met-BC, contrasting with non-metastatic breast cancer (NonMet-BC) patients, which displayed an enrichment in potential probiotic and anti-inflammatory species. Notably, we identified and verified a baseline prognostic signature for metastasis in BC patients, with its clinical relevance further validated by its impact on overall survival. In conclusion, the observed disparities in miRNA expression and species-level bacterial abundance suggest their involvement in BC progression. The development of a prognostic signature holds promise for metastasis risk assessment, paving the way for personalized interventions and improved clinical outcomes in BC patients.

An energy landscape approach reveals the potential key bacteria contributing to the development of inflammatory bowel disease

The dysbiosis of microbiota has been reported to be associated with numerous human pathophysiological processes, including inflammatory bowel disease (IBD). With advancements in high-throughput sequencing, various methods have been developed to study the alteration of microbiota in the development and progression of diseases. However, a suitable approach to assess the global stability of the microbiota in disease states through time-series microbiome data is yet to be established. In this study, we have introduced a novel Energy Landscape construction method, which incorporates the Latent Dirichlet Allocation (LDA) model and the pairwise Maximum Entropy (MaxEnt) model for their complementary advantages, and demonstrate its utility by applying it to an IBD time-series dataset. Through this approach, we obtained the microbial assemblages' energy profile of the whole microbiota under the IBD condition and uncovered the hidden stable stages of microbiota structure during the disease development with time-series microbiome data. The Bacteroides-dominated assemblages presenting in multiple stable states suggest the potential contribution of Bacteroides and interactions with other microbial genera, like Alistipes, and Faecalibacterium, to the development of IBD. Our proposed method provides a novel and insightful tool for understanding the alteration and stability of the microbiota under disease states and offers a more holistic view of the complex dynamics at play in microbiota-mediated diseases.

Dietary chlorogenic acid alleviates high-fat diet-induced steatotic liver disease by regulating metabolites and gut microbiota

The high-fat diet would lead to excessive fat storage in the liver to form metabolic dysfunction-associated steatotic liver disease (MASLD), and the trend is burgeoning. The aim of the study is to investigate the effects of chlorogenic acid (CGA) on metabolites and gut microorganisms in MASLD mice induced by a high-fat diet. In comparison to the HF group, the TC (total cholesterol), TG (total triglycerides), LDL-C (low-density lipoprotein cholesterol), AST (aspartate aminotransferase) and ALT (alanine transaminase) levels were reduced after CGA supplement. CGA led to an increase in l-phenylalanine, l-tryptophan levels, and promoted fatty acid degradation. CGA increased the abundance of the Muribaculaceae, Bacteroides and Parabacteroides. Changes in these microbes were significantly associated with the liver metabolites level and lipid profile level. These data suggest important roles for CGA regulating the gut microbiota, liver and caecum content metabolites, and TG-, TC- and LDL-C lowering function.

Parabacteroides distasonis-Derived Outer Membrane Vesicles Enhance Antitumor Immunity Against Colon Tumors by Modulating CXCL10 and CD8+ T Cells

Purpose

Given the potent immunostimulatory effects of bacterial outer membrane vesicles (OMVs) and the significant anti-colon tumor properties of Parabacteroides distasonis (Pd), this study aimed to elucidate the role and potential mechanisms of Pd-derived OMVs (Pd-OMVs) against colon cancer.

Methods

This study isolated and purified Pd-OMVs from Pd cultures and assessed their characteristics. The effects of Pd-OMVs on CT26 cell uptake, proliferation, and invasion were investigated in vitro. In vivo, a CT26 colon tumor model was used to investigate the anti-colon tumor effects and underlying mechanisms of Pd-OMVs. Finally, we evaluated the biosafety of Pd-OMVs.

Results

Purified Pd-OMVs had a uniform cup-shaped structure with an average size of 165.5 nm and a zeta potential of approximately -9.56 mV, and their proteins were associated with pathways related to immunity and apoptosis. In vitro experiments demonstrated that CT26 cells internalized the Pd-OMVs, resulting in a significant decrease in their proliferation and invasion abilities. Further in vivo studies confirmed the accumulation of Pd-OMVs in tumor tissues, which significantly inhibited the growth of colon tumors. Mechanistically, Pd-OMVs increased the expression of CXCL10, promoting infiltration of CD8+ T cells into tumor tissues and expression of pro-inflammatory factors TNF-α, IL-1β, and IL-6. Notably, Pd-OMVs demonstrated a high level of biosafety.

Conclusion

This paper elucidates that Pd-OMVs can exert significant anti-colon tumor effects by upregulating the expression of the chemokine CXCL10, thereby increasing the infiltration of CD8+ T cells into tumors and enhancing antitumor immune responses. This suggests that Pd-OMVs may be developed as a novel nanoscale potent immunostimulant with great potential for application in tumor immunotherapy. As well as developed as a novel nano-delivery carrier for combination with other antitumor drugs.

Intervention with fructooligosaccharides, Saccharomyces boulardii, and their combination in a colitis mouse model

Objective

To examine the effects of an intervention with fructooligosaccharides (FOS), Saccharomyces boulardii, and their combination in a mouse model of colitis and to explore the mechanisms underlying these effects.

Methods

The effects of FOS, S. boulardii, and their combination were evaluated in a DSS-induced mouse model of colitis. To this end, parameters such as body weight, the disease activity index (DAI), and colon length were examined in model mice. Subsequently, ELISA was employed to detect the serum levels of proinflammatory cytokines. Histopathological analysis was performed to estimate the progression of inflammation in the colon. Gas chromatography was used to determine the content of short-chain fatty acids (SCFAs) in the feces of model mice. Finally, 16S rRNA sequencing technology was used to analyze the gut microbiota composition.

Results

FOS was slight effective in treating colitis and colitis-induced intestinal dysbiosis in mice. Meanwhile, S. boulardii could significantly reduced the DAI, inhibited the production of IL-1β, and prevented colon shortening. Nevertheless, S. boulardii treatment alone failed to effectively regulate the gut microbiota. In contrast, the combined administration of FOS/S. boulardii resulted in better anti-inflammatory effects and enabled microbiota regulation. The FOS/S. boulardii combination (109 CFU/ml and 107 CFU/ml) significantly reduced the DAI, inhibited colitis, lowered IL-1β and TNF-α production, and significantly improved the levels of butyric acid and isobutyric acid. However, FOS/S. boulardii 109 CFU/ml exerted stronger anti-inflammatory effects, inhibited IL-6 production and attenuated colon shortening. Meanwhile, FOS/S. boulardii 107 CFU/ml improved microbial regulation and alleviated the colitis-induced decrease in microbial diversity. The combination of FOS and S. boulardii significantly increased the abundance of Parabacteroides and decreased the abundance of Escherichia-Shigella. Additionally, it promoted the production of acetic acid and propionic acid.

Conclusion

Compared with single administration, the combination can significantly increase the abundance of beneficial bacteria such as lactobacilli and Bifidobacteria and effectively regulate the gut microbiota composition. These results provide a scientific rationale for the prevention and treatment of colitis using a FOS/S. boulardii combination. They also offer a theoretical basis for the development of nutraceutical preparations containing FOS and S. boulardii.

Antihyperalgesic properties of gut microbiota: Parabacteroides distasonis as a new probiotic strategy to alleviate chronic abdominal pain

ABSTRACT

The potential role of gut microbiota in pain modulation is arousing an emerging interest since recent years. This study investigated neuromodulatory properties of gut microbiota to identify next-generation probiotics to propose alternative therapies for visceral pain management. Neuromodulation ability of 10 bacterial strains isolated from a healthy donor was assessed both on ND7/23 immortalized cell line and primary neuronal cells from rat dorsal root ganglia. This screening highlighted the neuroinhibitory property of Parabacteroides distasonis (F1-2) strain, supported both by its intracellular content and membrane fraction, which was further investigated in visceral pain mouse models. Oral administration of F1-2 resulted in a significant decrease of colonic hypersensitivity (CHS) in dextran sulfate sodium (0.5%) model associated with low-grade inflammation and a significant decrease of CHS in Citrobacter rodentium postinfectious models. No effect of F1-2 oral administration on CHS was observed in a neonatal maternal separation stress model. Antihyperalgesic effect unlikely involved modulation of inflammatory processes or restoration of intestinal barrier. Exploration of direct dialogue mechanisms between this strain and nervous system, assessed by calcium imaging experiments, revealed that F1-2 interacts directly with nociceptors by reducing activation level on capsaicin, inflammatory soup, and bradykinin stimulations. Our study provides new insights about bacteria-host interaction and places P distasonis as a potential therapeutic strategy in the treatment of visceral pain observed in leaky gut-associated pathologies.

Microbiome signatures associated with clinical stages of gastric Cancer: whole metagenome shotgun sequencing study

BACKGROUND

Gastric cancer is one of the global health concerns. A series of studies on the stomach have confirmed the role of the microbiome in shaping gastrointestinal diseases. Delineation of microbiome signatures to distinguish chronic gastritis from gastric cancer will provide a non-invasive preventative and treatment strategy. In this study, we performed whole metagenome shotgun sequencing of fecal samples to enhance the detection of rare bacterial species and increase genome sequence coverage. Additionally, we employed multiple bioinformatics approaches to investigate the potential targets of the microbiome as an indicator of differentiating gastric cancer from chronic gastritis.

RESULTS

A total of 65 patients were enrolled, comprising 33 individuals with chronic gastritis and 32 with gastric cancer. Within each group, the chronic gastritis group was sub-grouped into intestinal metaplasia (n = 15) and non-intestinal metaplasia (n = 18); the gastric cancer group, early stage (stages 1 and 2, n = 13) and late stage (stages 3 and 4, n = 19) cancer. No significant differences in alpha and beta diversities were detected among the patient groups. However, in a two-group univariate comparison, higher Fusobacteria abundance was identified in phylum; Fusobacteria presented higher abundance in gastric cancer (LDA scored 4.27, q = 0.041 in LEfSe). Age and sex-adjusted MaAsLin and Random Forest variable of importance (VIMP) analysis in species provided meaningful features; Bacteria_caccae was the most contributing species toward gastric cancer and late-stage cancer (beta:2.43, se:0.891, p:0.008, VIMP score:2.543). In contrast, Bifidobacterium_longum significantly contributed to chronic gastritis (beta:-1.8, se:0.699, p:0.009, VIMP score:1.988). Age, sex, and BMI-adjusted MasAsLin on metabolic pathway analysis showed that GLCMANNANAUT-PWY degradation was higher in gastric cancer and one of the contributing species was Fusobacterium_varium.

CONCLUSION

Microbiomes belonging to the pathogenic phylum Fusobacteria and species Bacteroides_caccae and Streptococcus_anginosus can be significant targets for monitoring the progression of gastric cancer. Whereas Bifidobacterium_longum and Lachnospiraceae_bacterium_5_1_63FAA might be protection biomarkers against gastric cancer.

Exopolysaccharides Produced by Bifidobacterium longum subsp. longum YS108R Ameliorates DSS-Induced Ulcerative Colitis in Mice by Improving the Gut Barrier and Regulating the Gut Microbiota

Ulcerative colitis (UC) is a major disease that has endangered human health. Our previous study demonstrated that Bifidobacterium longum subsp. longum YS108R, a ropy exopolysaccharide (EPS)-producing bacterium, could alleviate UC in mice, but it is unclear whether EPS is the key substance responsible for its action. In this study, we proposed to investigate the remitting effect of EPS from B. longum subsp. longum YS108R on UC in a DSS-induced UC mouse model. Water extraction and alcohol precipitation were applied to extract EPS from the supernatant of B. longum subsp. longum YS108R culture. Then the animal trial was performed, and the results indicated that YS108R EPS ameliorated colonic pathological damage and the intestinal barrier. YS108R EPS suppressed inflammation via NF-κB signaling pathway inhibition and attenuated oxidative stress via the Nrf2 signaling pathway activation. Remarkably, YS108R EPS regulated gut microbiota, as evidenced by an increase in short-chain fatty acid (SCFA)-producing bacteria and a decline in Gram-negative bacteria, resulting in an increase of propionate and butyrate and a reduction of lipopolysaccharide (LPS). Collectively, YS108R EPS manipulated the intestinal microbiota and its metabolites, which further improved the intestinal barrier and inhibited inflammation and oxidative stress, thereby alleviating UC.

Metagenomic analysis of the intestinal microbiome reveals the potential mechanism involved in Bacillus amyloliquefaciens in treating schistosomiasis japonica in mice

Schistosomiasis japonica is one of the neglected tropical diseases characterized by chronic hepatic, intestinal granulomatous inflammation and fibrosis, as well as dysbiosis of intestinal microbiome. Previously, the probiotic Bacillus amyloliquefaciens has been shown to alleviate the pathological injuries in mice infected with Schistosoma japonicum by improving the disturbance of the intestinal microbiota. However, the underlying mechanisms involved in this process remain unclear. In this study, metagenomics sequencing and functional analysis were employed to investigate the differential changes in taxonomic composition and functional genes of the intestinal microbiome in S. japonicum-infected mice treated with B. amyloliquefaciens. The results revealed that intervention with B. amyloliquefaciens altered the taxonomic composition of the intestinal microbiota at the species level in infected mice and significantly increased the abundance of beneficial bacteria. Moreover, the abundance of predicted genes in the intestinal microbiome was also significantly changed, and the abundance of xfp/xpk and genes translated to urease was significantly restored. Further analysis showed that Limosilactobacillus reuteri was positively correlated with several KEGG Orthology (KO) genes and metabolic reactions, which might play important roles in alleviating the pathological symptoms caused by S. japonicum infection, indicating that it has the potential to function as another effective therapeutic agent for schistosomiasis. These data suggested that treatment of murine schistosomiasis japonica by B. amyloliquefaciens might be induced by alterations in the taxonomic composition and functional gene of the intestinal microbiome in mice. We hope this study will provide adjuvant strategies and methods for the early prevention and treatment of schistosomiasis japonica.

IMPORTANCE

Targeted interventions of probiotics on gut microbiome were used to explore the mechanism of alleviating schistosomiasis japonica. Through metagenomic analysis, there were significant changes in the composition of gut microbiota in mice infected with Schistosoma japonicum and significant increase in the abundance of beneficial bacteria after the intervention of Bacillus amyloliquefaciens. At the same time, the abundance of functional genes was found to change significantly. The abundance of genes related to urease metabolism and xfp/xpk related to D-erythrose 4-phosphate production was significantly restored, highlighting the importance of Limosilactobacillus reuteri in the recovery and abundance of predicted genes of the gut microbiome. These results indicated potential regulatory mechanism between the gene function of gut microbiome and host immune response. Our research lays the foundation for elucidating the regulatory mechanism of probiotic intervention in alleviating schistosomiasis japonica, and provides potential adjuvant treatment strategies for early prevention and treatment of schistosomiasis japonica.

Fusobacterium nucleatum promotes tumor progression in KRAS p.G12D-mutant colorectal cancer by binding to DHX15

Fusobacterium nucleatum (F. nucleatum) promotes intestinal tumor growth and its relative abundance varies greatly among patients with CRC, suggesting the presence of unknown, individual-specific effectors in F. nucleatum-dependent carcinogenesis. Here, we identify that F. nucleatum is enriched preferentially in KRAS p.G12D mutant CRC tumor tissues and contributes to colorectal tumorigenesis in Villin-Cre/KrasG12D+/- mice. Additionally, Parabacteroides distasonis (P. distasonis) competes with F. nucleatum in the G12D mouse model and human CRC tissues with the KRAS mutation. Orally gavaged P. distasonis in mice alleviates the F. nucleatum-dependent CRC progression. F. nucleatum invades intestinal epithelial cells and binds to DHX15, a protein of RNA helicase family expressed on CRC tumor cells, mechanistically involving ERK/STAT3 signaling. Knock out of Dhx15 in Villin-Cre/KrasG12D+/- mice attenuates the CRC phenotype. These findings reveal that the oncogenic effect of F. nucleatum depends on somatic genetics and gut microbial ecology and indicate that personalized modulation of the gut microbiota may provide a more targeted strategy for CRC treatment.

Modulation of intestinal metabolites by calorie restriction and its association with gut microbiota in a xenograft model of colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is a common malignant tumor, and its occurrence and development are closely related to dysbiosis of gut microbes. Previously, we found calorie restriction altered the composition of the microbial community in a colorectal cancer mouse model and inhibited in vivo growth of CRC cells. Here, we aim to further investigate alteration in the intestinal metabolites and explore the interplay between gut microbiota and intestinal metabolites upon calorie restriction.

METHODS

Human colorectal cancer HCT116 cells were used to establish a colorectal cancer xenograft mouse model. The changes of intestinal metabolites in the ad libitum group and calorie restriction group were investigated through untargeted metabolomics analysis. The integrative analysis of gut microbiota and metabolites to elucidate the associations between gut microbiota and intestinal metabolites.

RESULTS

Compared with the mice in the ad libitum group, mice upon calorie restriction exhibited downregulation of Isoleucyl-Valine, and upregulation of D-Proline, 1-Palmitoylphosphatidylcholine, and 4-Trimethylammoniobutanoic acid. Additionally, an integrative analysis of gut microbiota and metabolites revealed that Lactobacillus, Parabacteroides and rC4-4 genus were upregulated in the calorie restriction group and positively correlated with D-Proline, 4-Trimethylammoniobutanoic acid or 1-Palmitoylphosphatidylcholine, while negatively correlated with Isoleucyl-Valine. In contrast, the Nitrospirae and Deferribacteres phylum exhibited opposite trends.

CONCLUSION

Calorie restriction affects the abundance of gut microbes such as Nitrospirae phylum and Lactobacillus genus in mouse model of colorectal cancer, leading to changes in the metabolites such as D-Proline、Isoleucyl-Valine, which contributes to the suppression of in vivo growth of CRC by calorie restriction.

Clonal Parabacteroides from Gut Microfistulous Tracts as Transmissible Cytotoxic Succinate-Commensal Model of Crohn's Disease Complications

Crohn's disease (CD) has been traditionally viewed as a chronic inflammatory disease that cause gut wall thickening and complications, including fistulas, by mechanisms not understood. By focusing on Parabacteroides distasonis (presumed modern succinate-producing commensal probiotic), recovered from intestinal microfistulous tracts (cavernous fistulous micropathologies CavFT proposed as intermediate between 'mucosal fissures' and 'fistulas') in two patients that required surgery to remove CD-damaged ilea, we demonstrate that such isolates exert pathogenic/pathobiont roles in mouse models of CD. Our isolates are clonally-related; potentially emerging as transmissible in the community and mice; proinflammatory and adapted to the ileum of germ-free mice prone to CD-like ileitis (SAMP1/YitFc) but not healthy mice (C57BL/6J), and cytotoxic/ATP-depleting to HoxB8-immortalized bone marrow derived myeloid cells from SAMP1/YitFc mice when concurrently exposed to succinate and extracts from CavFT-derived E. coli , but not to cells from healthy mice. With unique genomic features supporting recent genetic exchange with Bacteroides fragilis -BGF539, evidence of international presence in primarily human metagenome databases, these CavFT Pdis isolates could represent to a new opportunistic Parabacteroides species, or subspecies (' cavitamuralis' ) adapted to microfistulous niches in CD.

Maternal exposure of mice to glyphosate induces depression- and anxiety-like behavior in the offspring via alterations of the gut-brain axis

The past decade has been characterized by increased awareness and de-stigmatization of mental health issues, in particular the most common neuropsychiatric disorders depression and anxiety. Further, with growing understanding of neurodevelopmental disorders such as attention deficit and hyperactivity disorder and autism spectrum disorder, the number of diagnosed patients has increased. The pathogenesis of these behavioral disorders is multifactorial and early-life exposure to environmental chemicals has been proposed to be a relevant risk factor that might mediate these effects by disturbances on the gut-brain-axis. However, for glyphosate, the most widely used pesticide worldwide, there are only limited and inconsistent findings that link chronic low-dose exposure in particular during early life to neurobehavioral disorders. Here, we explored the impact of maternal oral glyphosate exposure (0.5 and 50 mg/kg body weight/day) during pregnancy and the lactational period on offspring's behavior, brain gene expression and gut microbiota using a cross-generational mouse model. Behavioral analyses revealed a depression- and anxiety-like behavior as well as social deficits most notably in adult female offspring of glyphosate-exposed dams. Furthermore, the expression of tryptophan hydroxylase 2, an enzyme discussed to be linked to behavioral problems, was reduced in the hippocampus of female offspring and correlated to a glyphosate-induced DNA hypermethylation of the gene. Moreover, maternal glyphosate exposure significantly altered the gut microbiota in the female offspring including a decreased abundance of Akkermansia and increased abundance of Alistipes and Blautia, bacteria involved in tryptophan metabolism and associated with depression- and anxiety-like disorders. Our results suggest that glyphosate might influence the gut-brain axis crosstalk following in-utero and lactational exposure. This study underlines the importance of understanding the impact of exposure to pesticides on the gut-brain axis and further emphasizes the need for microbiome analyses to be compulsorily included in health risk assessments of pesticides.

The co-regulation of the gut microbiome and host genes might play essential roles in metformin gastrointestinal intolerance

Metformin is commonly used, but approximately 20% of patients experience gastrointestinal intolerance, leading to medication discontinuation for unclear reasons and a lack of effective management strategies. In this study, the 18 fecal and blood samples were analyzed using 16S rRNA and mRNA transcriptome, respectively. These samples included 3 fecal and 4 blood from metformin-tolerant T2D patients before and after metformin treatment (T and Ta), 3 fecal and 5 blood from metformin-intolerant T2D patients before and after treatment (TS and TSa), and 6 fecal samples from healthy controls. The results showed that certain anti-inflammatory gut bacteria and gene, such as Barnesiella (p = 0.046), Parabacteroides goldsteinii (p = 0.016), and the gene JUND (p = 0.0002), exhibited higher levels in metformin-intolerant patients, and which decreased after metformin treatment (p < 0.05). This potentially invalidates patients' anti-inflammatory effect and intestinal mucus barrier protection, which may lead to alterations in intestinal permeability, decreased gut barrier function, and gastrointestinal symptoms, including diarrhea, bloating, and nausea. After metformin treatment, primary bile acids (PBAs) production species: Weissella confusa, Weissella paramesenteroides, Lactobacillus brevis, and Lactobacillus plantarum increased (p < 0.05). The species converting PBAs to secondary bile acids (SBAs): Parabacteroides distasonis decreased (p < 0.05). This might result in accumulation of PBAs, which also may lead to anti-inflammatory gene JUND and SQSTM1 downregulated. In conclusion, this study suggests that metformin intolerance may be attributed to a decrease in anti-inflammatory-related flora and genes, and also alterations in PBAs accumulation-related flora. These findings open up possibilities for future research targeting gut flora and host genes to prevent metformin intolerance.

Targeting IL-23 for the interception of obesity-associated colorectal cancer

Inflammation and obesity are two major factors that promote Colorectal cancer (CRC). Our recent data suggests that interleukin (IL)-23, is significantly elevated in CRC tumors and correlates with patient obesity, tumor grade and survival. Thus, we hypothesize that obesity and CRC may be linked via inflammation and IL-23 may be a potential target for intervention in high-risk patients. TCGA dataset and patient sera were evaluated for IL-23A levels. IL-23A [IL-23 p19-/-] knockout (KO) mice were crossed to Apcmin/+ mice and progeny were fed low-fat or high-fat diets. At termination intestines were evaluated for tumorigenesis. Tumors, serum, and fecal contents were analyzed for protein biomarkers, cytokines, and microbiome profile respectively. IL-23A levels are elevated in the sera of patients with obesity and colon tumors. Genetic ablation of IL-23A significantly suppressed colonic tumor multiplicity (76-96 %) and incidence (72-95 %) in male and female mice. Similarly, small-intestinal tumor multiplicity and size were also significantly reduced in IL-23A KO mice. IL-23A knockdown in Apcmin/+ mice fed high-fat diet, also resulted in significant suppression of colonic (50-58 %) and SI (41-48 %) tumor multiplicity. Cytokine profiling showed reduction in several circulating pro-inflammatory cytokines including loss of IL-23A. Biomarker analysis suggested reduced tumor cell proliferation and immune modulation with an increase in tumor-infiltrating CD4+ and CD8+ T-lymphocytes in the IL-23A KO mice compared to controls. Fecal microbiome analysis revealed potentially beneficial changes in the bacterial population profile. In summary, our data indicates a tumor promoting role for IL-23 in CRC including diet-induced obesity. With several IL-23 targeted therapies in clinical trials, there is a great potential for targeting this cytokine for CRC prevention and therapy.

Identification of Gut Microbiota Profile Associated with Colorectal Cancer in Saudi Population

Colorectal cancer (CRC) is a significant global health concern. Microbial dysbiosis and associated metabolites have been associated with CRC occurrence and progression. This study aims to analyze the gut microbiota composition and the enriched metabolic pathways in patients with late-stage CRC. In this study, a cohort of 25 CRC patients diagnosed at late stage III and IV and 25 healthy participants were enrolled. The fecal bacterial composition was investigated using V3-V4 ribosomal RNA gene sequencing, followed by clustering and linear discriminant analysis (LDA) effect size (LEfSe) analyses. A cluster of ortholog genes' (COG) functional annotations and the Kyoto Encyclopedia of Genes and Genomes (KEGG) were employed to identify enrichment pathways between the two groups. The findings showed that the fecal microbiota between the two groups varied significantly in alpha and beta diversities. CRC patients' fecal samples had significantly enriched populations of Streptococcus salivarius, S. parasanguins, S. anginosus, Lactobacillus mucosae, L. gasseri, Peptostreptococcus, Eubacterium, Aerococcus, Family XIII_AD3001 Group, Erysipelatoclostridium, Escherichia-Shigella, Klebsiella, Enterobacter, Alistipes, Ralstonia, and Pseudomonas (Q < 0.05). The enriched pathways identified in the CRC group were amino acid transport, signaling and metabolism, membrane biogenesis, DNA replication and mismatch repair system, and protease activity (Q < 0.05). These results suggested that the imbalance between intestinal bacteria and the elevated level of the predicated functions and pathways may contribute to the development of advanced CRC tumors. Further research is warranted to elucidate the exact role of the gut microbiome in CRC and its potential implications for use in diagnostic, prevention, and treatment strategies.

Combined oral intake of short and long fructans alters the gut microbiota in food allergy model mice and contributes to food allergy prevention

BACKGROUND

It has become clear that the intestinal microbiota plays a role in food allergies. The objective of this study was to assess the food allergy-preventive effects of combined intake of a short fructan (1-kestose [Kes]) and a long fructan (inulin ([Inu]) in an ovalbumin (OVA)-induced food allergy mouse model.

RESULTS

Oral administration of fructans lowered the allergenic symptom score and alleviated the decreases in rectal temperature and total IgA levels and increases in OVA-specific IgE and IgA levels induced by high-dose OVA challenge, and in particular, combined intake of Kes and Inu significantly suppressed the changes in all these parameters. The expression of the pro-inflammatory cytokine IL-4, which was increased in the allergy model group, was significantly suppressed by fructan administration, and the expression of the anti-inflammatory cytokine IL-10 was significantly increased upon Kes administration. 16 S rRNA amplicon sequencing of the gut microbiota and beta diversity analysis revealed that fructan administration may induce gut microbiota resistance to food allergy sensitization, rather than returning the gut microbiota to a non-sensitized state. The relative abundances of the genera Parabacteroides B 862,066 and Alloprevotella, which were significantly reduced by food allergy sensitization, were restored by fructan administration. In Parabacteroides, the relative abundances of Parabacteroides distasonis, Parabacteroides goldsteinii, and their fructan-degrading glycoside hydrolase family 32 gene copy numbers were increased upon Kes or Inu administration. The concentrations of short-chain fatty acids (acetate and propionate) and lactate were increased by fructan administration, especially significantly in the Kes + Inu, Kes, and Inu-fed (Inu, Kes + Inu) groups.

CONCLUSION

Combined intake of Kes and Inu suppressed allergy scores more effectively than single intake, suggesting that Kes and Inu have different allergy-preventive mechanisms. This indicates that the combined intake of these short and long fructans may have an allergy-preventive benefit.

Functional proteins in breast milk and their correlation with the development of the infant gut microbiota: a study of mother-infant pairs

Introduction

Proteins in breast milk play an important role in the growth and development of infants. This study aims to explore the correlation between functional proteins in breast milk and the infant gut microbiota.

Methods

Twenty-three mothers and their infants were enrolled and breast milk samples and infant fecal samples were collected. Breast milk protein content was determined by UPLC-MS/MS, and 16S rRNA sequencing was employed to analyze the gut microbiota of infant.

Results

The results indicated that the secretory immunoglobulin A (sIgA) content in breast milk was positively correlated with the abundance of Veillonella parvula. The κ-casein content was positively correlated with the abundance of Clostridium butyricum. The osteopontin (OPN) and lactalbumin contents were positively correlated with the abundance of Parabacteroides distasonis at 42 days. Functional pathway analysis showed that the OPN and κ-casein contents in breast milk were significantly correlated with amino acid, pyruvate, propionic acid, linoleic acid, and alpha-linolenic acid metabolic pathways in early life.

Discussion

The results of this study suggest that specific proteins in breast milk can influence the abundance of certain gut microbes in infants, playing an important role in early immune and metabolic development.

Salivary and fecal microbiota: potential new biomarkers for early screening of colorectal polyps

Objective

Gut microbiota plays an important role in colorectal cancer (CRC) pathogenesis through microbes and their metabolites, while oral pathogens are the major components of CRC-associated microbes. Multiple studies have identified gut and fecal microbiome-derived biomarkers for precursors lesions of CRC detection. However, few studies have used salivary samples to predict colorectal polyps. Therefore, in order to find new noninvasive colorectal polyp biomarkers, we searched into the differences in fecal and salivary microbiota between patients with colorectal polyps and healthy controls.

Methods

In this case-control study, we collected salivary and fecal samples from 33 patients with colorectal polyps (CP) and 22 healthy controls (HC) between May 2021 and November 2022. All samples were sequenced using full-length 16S rRNA sequencing and compared with the Nucleotide Sequence Database. The salivary and fecal microbiota signature of colorectal polyps was established by alpha and beta diversity, Linear discriminant analysis Effect Size (LEfSe) and random forest model analysis. In addition, the possibility of microbiota in identifying colorectal polyps was assessed by Receiver Operating Characteristic Curve (ROC).

Results

In comparison to the HC group, the CP group's microbial diversity increased in saliva and decreased in feces (p < 0.05), but there was no significantly difference in microbiota richness (p > 0.05). The principal coordinate analysis revealed significant differences in β-diversity of salivary and fecal microbiota between the CP and HC groups. Moreover, LEfSe analysis at the species level identified Porphyromonas gingivalis, Fusobacterium nucleatum, Leptotrichia wadei, Prevotella intermedia, and Megasphaera micronuciformis as the major contributors to the salivary microbiota, and Ruminococcus gnavus, Bacteroides ovatus, Parabacteroides distasonis, Citrobacter freundii, and Clostridium symbiosum to the fecal microbiota of patients with polyps. Salivary and fecal bacterial biomarkers showed Area Under ROC Curve of 0.8167 and 0.8051, respectively, which determined the potential of diagnostic markers in distinguishing patients with colorectal polyps from controls, and it increased to 0.8217 when salivary and fecal biomarkers were combined.

Conclusion

The composition and diversity of the salivary and fecal microbiota were significantly different in colorectal polyp patients compared to healthy controls, with an increased abundance of harmful bacteria and a decreased abundance of beneficial bacteria. A promising non-invasive tool for the detection of colorectal polyps can be provided by potential biomarkers based on the microbiota of the saliva and feces.

Altered gut microbiota community structure and correlated immune system changes in dibutyl phthalate exposed mice

Di-n-butyl phthalate (DBP) is a ubiquitous environmental contaminant linked with various adverse health effects, including immune system dysfunction. Gut microbial dysbiosis can contribute to a wide range of pathogenesis, particularly immune disease. Here, we investigated the impact of DBP on the gut microbiome and examined correlations with immune system changes after five weeks oral exposure (10 or 100 mg/kg/day) in adult male mice. The fecal microbiome composition was characterized using 16S rRNA sequencing. DBP-treated mice displayed a significantly distinct microbial community composition, indicated by Bray-Curtis distance. Numerous amplicon sequence variants (ASVs) at the genus level were altered. Compared to the vehicle control group, the 10 mg/kg/day DBP group had 63 more abundant and 65 less abundant ASVs, while 60 ASVs were increased and 76 ASVs were decreased in the 100 mg/kg/day DBP group. Both DBP treatment groups showed higher abundances of ASVs assigned to Desulfovibrio (Proteobacteria phylum) and Enterorhabdus genera, while ASVs belonging to Parabacteroides, Lachnospiraceae UCG-006 and Lachnoclostridium were less common compared to the control group. Interestingly, an ASV belonging to Rumniniclostridium 6, which was less abundant in DBP-treated mice, demonstrated a negative correlation with the increased number of non-classical monocytes observed in the blood of DBP-treated animals. In addition, an ASV from Lachnospiraceae UCG-001, which was more abundant in the DBP-treated animals, showed a positive correlation with the non-classical monocyte increase. This study shows that DBP exposure greatly modifies the gut bacterial microbiome and indicates a potential contribution of microbial dysbiosis to DBP-induced immune system impairment, illustrating the importance of investigating how interactions between exposome components can affect health.

Tributyrin alleviates gut microbiota dysbiosis to repair intestinal damage in antibiotic-treated mice

Tributyrin (TB) is a butyric acid precursor and has a key role in anti-inflammatory and intestinal barrier repair effects by slowly releasing butyric acid. However, its roles in gut microbiota disorder caused by antibiotics remain unclear. Herein, we established an intestinal microbiota disorder model using ceftriaxone sodium via gavage to investigate the effects of different TB doses for restoring gut microbiota and intestinal injury. First, we divided C57BL/6 male mice into two groups: control (NC, n = 8) and experimental (ABx, n = 24) groups, receiving gavage with 0.2 mL normal saline and 400 mg/mL ceftriaxone sodium solution for 7 d (twice a day and the intermediate interval was 6 h), respectively. Then, mice in the ABx group were randomly split into three groups: model (M, 0.2 mL normal saline), low TB group (TL, 0.3 g/kg BW), and high TB group (TH, 3 g/kg BW) for 11 d. We found that TB supplementation alleviated antibiotics-induced weight loss, diarrhea, and intestinal tissue damage. The 16S rRNA sequence analysis showed that TB intervention increased the α diversity of intestinal flora, increased potential short-chain fatty acids (SCFAs)-producing bacteria (such as Muribaculaceae and Bifidobacterium), and inhibited the relative abundance of potentially pathogenic bacteria (such as Bacteroidetes and Enterococcus) compared to the M group. TB supplementation reversed the reduction in SCFAs production in antibiotic-treated mice. Additionally, TB downregulated the levels of serum LPS and zonulin, TNF-α, IL-6, IL-1β and NLRP3 inflammasome-related factors in intestinal tissue and upregulated tight junction proteins (such as ZO-1 and Occludin) and MUC2. Overall, the adjustment ability of low-dose TB to the above indexes was stronger than high-dose TB. In conclusion, TB can restore the dysbiosis of gut microbiota, increase SCFAs, suppress inflammation, and ameliorate antibiotic-induced intestinal damage, indicating that TB might be a potential gut microbiota modulator.

Gender-specific changes of the gut microbiome correlate with tumor development in murine models of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with a dismal outcome. To improve understanding of sequential microbiome changes during PDAC development we analyzed mouse models of pancreatic carcinogenesis (KC mice recapitulating pre-invasive PanIN formation, as well as KPC mice recapitulating invasive PDAC) during early tumor development and subsequent tumor progression. Diversity and community composition were analyzed depending on genotype, age, and gender. Both mouse models demonstrated concordant abundance changes of several genera influenced by one or more of the investigated factors. Abundance was significantly impacted by gender, highlighting the need to further elucidate the impact of gender differences. The findings underline the importance of the microbiome in PDAC development and indicate that microbiological screening of patients at risk and targeting the microbiome in PDAC development may be feasible in future.

Sex difference in prebiotics on gut and blood-brain barrier dysfunction underlying stress-induced anxiety and depression

BACKGROUND

Most of the previous studies have demonstrated the potential antidepressive and anxiolytic role of prebiotic supplement in male subjects, yet few have females enrolled. Herein, we explored whether prebiotics administration during chronic stress prevented depression-like and anxiety-like behavior in a sex-specific manner and the mechanism of behavioral differences caused by sex.

METHODS

Female and male C57 BL/J mice on normal diet were supplemented with or without a combination of fructo-oligosaccharides (FOS) and galacto-oligosaccharides (GOS) during 3- and 4-week chronic restraint stress (CRS) treatment, respectively. C57 BL/J mice on normal diet without CRS were used as controls. Behavior consequences, gut microbiota, dysfunction of gut and brain-blood barriers, and inflammatory profiles were measured.

RESULTS

In the 3rd week, FOS + GOS administration attenuated stress-induced anxiety-like behavior in female, but not in male mice, and the anxiolytic effects in males were observed until the 4th week. However, protective effects of prebiotics on CRS-induced depression were not observed. Changes in the gene expression of tight junction proteins in the distal colon and hippocampus, and decreased number of colon goblet cells following CRS were restored by prebiotics only in females. In both female and male mice, prebiotics alleviated stress-induced BBB dysfunction and elevation in pro-inflammatory cytokines levels, and modulated gut microbiota caused by stress. Furthermore, correlation analysis revealed that anxiety-like behaviors were significantly correlated with levels of pro-inflammatory cytokines and gene expression of tight junction proteins in the hippocampus of female mice, and the abundance of specific gut microbes was also correlated with anxiety-like behaviors, pro-inflammatory cytokines, and gene expression of tight junction proteins in the hippocampus of female mice.

CONCLUSION

Female mice were more vulnerable to stress and prebiotics than males. The gut microbiota, gut and blood-brain barrier, and inflammatory response may mediate the protective effects of prebiotics on anxiety-like behaviors in female mice.

Zearalenone attenuates colitis associated colorectal tumorigenesis through Ras/Raf/ERK pathway suppression and SCFA-producing bacteria promotion

The high prevalence of colorectal cancer (CRC) and its leading death causing rate have placed a considerable burden on patients and healthcare providers. There is a need for a therapy that has fewer adverse effects and greater efficiency. Zearalenone (ZEA), an estrogenic mycotoxin, has been demonstrated to exert apoptotic properties when administrated in higher doses. However, it is unclear whether such apoptotic effect remains valid in an in vivo setting. The current study aimed to investigate the effect of ZEA on CRC and its underlying mechanisms in the azoxymethane/ dextran sodium sulfate (AOM/DSS) model. Our results revealed that ZEA significantly lowered the total number of tumours, colon weight, colonic crypt depth, collagen fibrosis and spleen weight. ZEA suppressed Ras/Raf/ERK/cyclin D1 pathway, increasing the expression of apoptosis parker, cleaved caspase 3, while decreasing the expression of proliferative marker, Ki67 and cyclin D1. The gut microbiota composition in ZEA group showed higher stability and lower vulnerability in the microbial community when compared to AOM/DSS group. ZEA increased the abundance of short chain fatty acids (SCFAs) producing bacteria unidentified Ruminococcaceae, Parabacteroidies and Blautia, as well as the faecal acetate content. Notably, unidentified Ruminococcaceae and Parabacteroidies were substantially correlated with the decrease in tumour count. Overall, ZEA demonstrated a promising inhibitory effect on colorectal tumorigenesis and exhibited the potential for further development as a CRC treatment.

Disruption of Genes Encoding Putative Zwitterionic Capsular Polysaccharides of Diverse Intestinal Bacteroides Reduces the Induction of Host Anti-Inflammatory Factors

Bacterial zwitterionic capsular polysaccharides (ZPS), such as polysaccharide A (PSA) of the intestinal commensal Bacteroides fragilis, have been shown to modulate T cells, including inducing anti-inflammatory IL-10-secreting T regulatory cells (Tregs). We previously used a genomic screen to identify diverse host-associated bacteria with the predicted genetic capacity to produce ZPSs related to PSA of B. fragilis and hypothesized that genetic disruption (KO) of a key functional gene within these operons would reduce the anti-inflammatory activity of these bacteria. We found that ZPS-KO bacteria in two common gut commensals, Bacteroides uniformis and Bacteroides cellulosilyticus, had a reduced ability to induce Tregs and IL-10 in stimulations of human peripheral blood mononuclear cells (PBMCs). Additionally, we found that macrophage stimulated with either wildtype B. fragilis or B. uniformis produced significantly more IL-10 than KOs, indicating a potentially novel function of ZPS of shifting the cytokine response in macrophages to a more anti-inflammatory state. These findings support the hypothesis that these related ZPS may represent a shared strategy to modulate host immune responses.

Tigecycline reduces tumorigenesis in colorectal cancer via inhibition of cell proliferation and modulation of immune response

BACKGROUND

and Purpose: Colorectal cancer (CRC) is one of the cancers with the highest incidence in which APC gene mutations occur in almost 80% of patients. This mutation leads to β-catenin aberrant accumulation and an uncontrolled proliferation. Apoptosis evasion, changes in the immune response and microbiota composition are also events that arise in CRC. Tetracyclines are drugs with proven antibiotic and immunomodulatory properties that have shown cytotoxic activity against different tumor cell lines.

EXPERIMENTAL APPROACH

The effect of tigecycline was evaluated in vitro in HCT116 cells and in vivo in a colitis-associated colorectal cancer (CAC) murine model. 5-fluorouracil was assayed as positive control in both studies.

KEY RESULTS

Tigecycline showed an antiproliferative activity targeting the Wnt/β-catenin pathway and downregulating STAT3. Moreover, tigecycline induced apoptosis through extrinsic, intrinsic and endoplasmic reticulum pathways converging on an increase of CASP7 levels. Furthermore, tigecycline modulated the immune response in CAC, reducing the cancer-associated inflammation through downregulation of cytokines expression. Additionally, tigecycline favored the cytotoxic activity of cytotoxic T lymphocytes (CTLs), one of the main immune defenses against tumor cells. Lastly, the antibiotic reestablished the gut dysbiosis in CAC mice increasing the abundance of bacterial genera and species, such as Akkermansia and Parabacteroides distasonis, that act as protectors against tumor development. These findings resulted in a reduction of the number of tumors and an amelioration of the tumorigenesis process in CAC.

CONCLUSION AND IMPLICATIONS

Tigecycline exerts a beneficial effect against CRC supporting the use of this antibiotic for the treatment of this disease.

A Novel E3 Probiotics Formula Restored Gut Dysbiosis and Remodelled Gut Microbial Network and Microbiome Dysbiosis Index (MDI) in Southern Chinese Adult Psoriasis Patients

Psoriasis is a common chronic immune-mediated inflammatory skin disease with the association of various comorbidities. Despite the introduction of highly effective biologic therapies over the past few decades, the exact trigger for an immune reaction in psoriasis is unclear. With the majority of immune cells residing in the gut, the effect of gut microbiome dysbiosis goes beyond the gastrointestinal site and may exacerbate inflammation and regulate the immune system elsewhere, including but not limited to the skin via the gut-skin axis. In order to delineate the role of the gut microbiome in Southern Chinese psoriasis patients, we performed targeted 16S rRNA sequencing and comprehensive bioinformatic analysis to compare the gut microbiome profile of 58 psoriasis patients against 49 healthy local subjects presumably with similar lifestyles. Blautia wexlerae and Parabacteroides distasonis were found to be enriched in psoriasis patients and in some of the healthy subjects, respectively. Metabolic functional pathways were predicted to be differentially abundant, with a clear shift toward SCFA synthesis in healthy subjects. The alteration of the co-occurrence network was also evident in the psoriasis group. In addition, we also profiled the gut microbiome in 52 of the 58 recruited psoriasis patients after taking 8 weeks of an orally administrated novel E3 probiotics formula (with prebiotics, probiotics and postbiotics). The Dermatological Life Quality Index (p = 0.009) and Psoriasis Area and Severity Index (p < 0.001) were significantly improved after taking 8 weeks of probiotics with no adverse effect observed. We showed that probiotics could at least partly restore gut dysbiosis via the modulation of the gut microbiome. Here, we also report the potential application of a machine learning-derived gut dysbiosis index based on a quantitative PCR panel (AUC = 0.88) to monitor gut dysbiosis in psoriasis patients. To sum up, our study suggests the gut microbial landscape differed in psoriasis patients at the genera, species, functional and network levels. Additionally, the dysbiosis index could be a cost-effective and rapid tool to monitor probiotics use in psoriasis patients.

Faecalibacterium prausnitzii prevents hepatic damage in a mouse model of NASH induced by a high-fructose high-fat diet

Introduction

Nonalcoholic steatohepatitis (NASH) is an advanced nonalcoholic fatty liver disease characterized by chronic inflammation and fibrosis. A dysbiosis of the gut microbiota has been associated with the pathophysiology of NASH, and probiotics have proven helpful in its treatment and prevention. Although both traditional and next-generation probiotics have the potential to alleviate various diseases, studies that observe the therapeutic effect of next-generation probiotics on NASH are lacking. Therefore, we investigated whether a next-generation probiotic candidate, Faecalibacterium prausnitzii, contributed to the mitigation of NASH.

Methods

In this study, we conducted 16S rRNA sequencing analyses in patients with NASH and healthy controls. To test F. prausnitzii could alleviate NASH symptoms, we isolated four F. prausnitzii strains (EB-FPDK3, EB-FPDK9, EB-FPDK11, and EB-FPYYK1) from fecal samples collected from four healthy individuals. Mice were maintained on a high-fructose high-fat diet for 16 weeks to induce a NASH model and received oral administration of the bacterial strains. Changes in characteristic NASH phenotypes were assessed via oral glucose tolerance tests, biochemical assays, and histological analyses.

Results

16S rRNA sequencing analyses confirmed that the relative abundance of F. prausnitzii reduced significantly in patients with NASH compared to healthy controls (p &lt; 0.05). In the NASH mice, F. prausnitzii supplementation improved glucose homeostasis, prevented hepatic lipid accumulation, curbed liver damage and fibrosis, restored damaged gut barrier functions, and alleviated hepatic steatosis and liver inflammation. Furthermore, real-time PCR assays documented that the four F. prausnitzii strains regulated the expression of genes related to hepatic steatosis in these mice.

Discussion

Our study, therefore, confirms that the administration of F. prausnitzii bacteria can alleviate NASH symptoms. We propose that F. prausnitzii has the potential to contribute to the next-generation probiotic treatment of NASH.

Pregnancy-induced changes to the gut microbiota drive macrophage pyroptosis and exacerbate septic inflammation

The physiological and immune changes that occur during pregnancy are associated with worsened disease outcomes during infection and sepsis. How these perturbations exacerbate inflammation has not been explored. Here, using antibiotic treatment and fecal microbial transfers, we showed that sepsis susceptibility is driven by pregnancy-induced changes to gut microbiome in mice and humans. Integrative multiomics and genetically engineered bacteria revealed that reduced Parabacteroides merdae (P. merdae) abundance during pregnancy led to decreased formononetin (FMN) and increased macrophage death. Mechanistically, FMN inhibited macrophage pyroptosis by suppressing nuclear accumulation of hnRNPUL2 and subsequent binding to the Nlrp3 promoter. Treatment with FMN or deletion of murine hnRNPUL2 protected against septic inflammation. Intestinal abundances of P. merdae and FMN inversely correlated with the progression of septic patients. Our data reveal a microbe-immune axis that is disrupted in pregnant septic hosts, highlighting the potential of the FMN-hnRNPUL2-NLRP3 axis in providing promising therapeutic strategies for sepsis.

Transgenerational inheritance of wing development defects in Drosophila melanogaster induced by cadmium

The transgenerational inheritance of phenotype induced by environmental factors is a new focus in epigenetic research. In this study, Drosophila melanogaster (F₀) was cultured in the medium containing cadmium (Cd, 4.5 mg/kg) from eggs to adults, and offspring (F₁-F₄) were continuously kept in standard medium (without cadmium). The phenotype analysis showed that cadmium induced developmental defects on wings and apoptosis in the wing disc cells of Drosophila (F₀). The wing defects were transmitted for at least four generations even without Cd afterwards. And the effect on the mRNA expression of wing development related genes (shg, omb, F-actin, Mekk1) can be maintained for at least two or three generations. More importantly, under cadmium stress, the post-translational modification (PTM) on the histones H3K4me3 in the third instar larvae and ovaries or testes of adult flies increased significantly, while the levels of H3K9me3 and H3K27me3 decreased significantly. The expression of histone methylation related genes (dSet-1, ash1, Lsd1) increased significantly and these changes can be transmitted to offspring from one or two generations in ovaries or testes. These results suggest that the phenotypic defects of wings caused by cadmium can be inherited to the offspring, and this transgenerational inheritance effect may be related to the epigenetic regulation of histone methylation. Therefore, the adaptability of offspring should be considered when evaluating the toxicity and environmental risk of cadmium.

Extraction, Purification, and Chemical Degradation of LPS from Gut Microbiota Strains

It is estimated that more than 500 different bacterial species colonize the human gut, and they are collectively known as the gut microbiota. Such a massive bacterial presence is now considered an additional organ of the human body, thus becoming the object of an intense and daily growing research activity. Gram-negative bacteria represent a large percentage of the gut microbiota strains. The main constituent of the outer membrane of Gram-negatives is the lipopolysaccharide (LPS). Since its first discovery, LPS has been extensively studied for its structure-dependent capability to elicit a potent immune inflammatory reaction when perceived by specific immune receptors present in our body. Therefore, traditionally, LPS, due to its peculiar chemistry, has been associated with pathogenic bacteria, and it has been extensively studied for its dangerous effects on human health. However, LPS is also expressed on the cell surface of harmless and beneficial bacteria that colonize our intestines. This necessarily implies that the LPS from harmless gut microbes is "chemically different" from that owned by pathogenic ones, hence enabling successful colonization of the intestinal tract without creating a threat to the host immune system. Deciphering the structural features of LPS from these gut bacteria is essential to improve our still scarce knowledge of how the human host lives in a harmonious relationship with its own microbiota. To this end, LPS extraction and purification are essential steps in this field of research. Yet working with gut bacteria is extremely complex for a number of reasons, one being related to the fact that they produce an array of other glycans and glycoconjugates, such as capsular polysaccharides and/or exopolysaccharides, which render the isolation and characterization of the sole LPS not at all trivial. Here, we provide a protocol that might help when dealing with LPS from gut microbial species. We describe the preliminary manipulations and checks, extraction, and purification approaches, as well as the necessary chemical manipulations that should be performed to enable the characterization of the structure of an LPS by means of techniques like nuclear magnetic resonance spectroscopy and mass spectrometry.

Human cathelicidin LL-37 exerts amelioration effects against EHEC O157:H7 infection regarding inflammation, enteric dysbacteriosis, and impairment of gut barrier function

Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 infection impairs intestinal barrier function, causing intestinal inflammation and enteric dysbacteriosis. The human cathelicidin LL-37 can regulate excessive inflammatory responses, barrier function, and balance the intestinal microbial community; however, little is known about its effects on inflammation, intestinal barrier function, and microbiota disorders in EHEC O157:H7-infected mice. In this study, we investigated the protective effect of LL-37 against EHEC O157:H7 infection and elucidated the underlying mechanism using a mouse model. LL-37 treatment was found to inhibit body weight loss, restore edema and destruction of the intestinal villi, and significantly reduce epithelial apoptosis (P < 0.05) in EHEC O157:H7-infected mice. Furthermore, inflammatory infiltration of macrophages and neutrophils into the jejunum and colon was significantly decreased (P < 0.05). LL-37 significantly downregulated the production of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) (P < 0.05) and upregulated the anti-inflammatory cytokine (IL-10) during EHEC O157:H7 infection. LL-37 increased the expression of tight junction proteins (ZO-1, ZO-2, claudin-1, and occludin), which are associated with intestinal barrier function, and had a positive effect on EHEC O157:H7-induced microbial disorders, particularly in terms of the inflammation-related microbiota. LL-37 also significantly decreased the E. coli load in the liver and spleen (P < 0.01) and restored the structure of the liver and kidney. Taken together, LL-37 conferred protection in a EHEC O157:H7-induced mouse model by reducing intestinal inflammation, enhancing intestinal barrier function, and restoring the balance of the intestinal microbiota, which indicates the therapeutic potential of LL-37 against pathogen infection.

Early intestinal microbiota changes in aged and adult mice with sepsis

Background

The mortality rate associated with sepsis in elderly individuals is higher than that in younger individuals. The intestinal microbiota has been demonstrated to play an important role in the occurrence and development of sepsis. The purpose of this study was to investigate the differences in the intestinal microbiota between aged and adult mice with sepsis.

Methods

Thirty male C57BL mice were randomly divided into two groups: 15 in the adult group (AD group) and 15 in the age group (Age group). All the mice underwent caecal ligation and puncture to induce sepsis. Mice faeces were collected, and analysed using 16S rRNA sequencing. The liver and colon tissues were collected.

Results

There were significant differences in intestinal microbiota composition between the two groups. Compared with adult sepsis mice, the diversity of intestinal microbiota in the aged group was significantly reduced and the structure of dominant intestinal microbiota was changed. In the Age group, the microbiota associated with inflammatory factors increased, and the microbiota associated with the production of SCFAs (Ruminiclostridium, Prevotellaceae_UCG-001, Rikenella, Parabacteroides, Oscillibacter, Odoribacter, Muribaculum, Lachnoclostridium, Intestinimonas, Faecalibaculum, Anaerotruncus, Alloprevotella and Absiella) decreased. The metabolic pathways related to the microbiota also changed. Moreover, the proportion of inflammatory factors in Age group was higher than that in AD group.

Conclusion

Our results showed that there were significant differences in the abundance and structure of microbiota between aged and adult sepsis mice, Aged sepsis mice have more severe intestinal microbiota destruction and liver tissue inflammation than adult sepsis mice.

Partially hydrolyzed guar gum alleviates hepatic steatosis and alters specific gut microbiota in a murine liver injury model

PURPOSE

The gut microbiota, via the gut-liver axis, plays an important role in the development of intestinal failure-associated liver disease. Here, we investigated whether partially hydrolyzed guar gum (PHGG), a dietary fiber could alleviate liver damage and modulate the gut microbiota in a murine liver injury (LI) model.

METHODS

Liver injury was induced in 6-week-old male C57BL/6 mice using an enteral liquid diet composed of parenteral nutrition (LI group) and treated with 5% PHGG (LI/PHGG group). Liver histopathology was examined using oil red O and a tumor necrosis factor-α (TNF-α) labeling. The gut microbiota was examined using 16S rRNA gene sequencing.

RESULTS

Lipid accumulation was significantly decreased in the LI /PHGG group when compared with that of the LI group. The area of TNF-α-positive cells was significantly higher in the LI group when compared with that of the control. The principal coordinate analysis (PCoA) revealed pronounced changes in the gut microbiota after PHGG treatment. Linear discriminant analysis of effect size showed that PHGG treatment significantly increased cecal abundance of Parabacteroides.

CONCLUSIONS

PHGG alleviated hepatic steatosis following liver injury in mice. The protective effect of PHGG treatment could be associated with increased abundance of Parabacteroides in the cecum.

Cigarette smoke promotes colorectal cancer through modulation of gut microbiota and related metabolites

OBJECTIVE

Cigarette smoking is a major risk factor for colorectal cancer (CRC). We aimed to investigate whether cigarette smoke promotes CRC by altering the gut microbiota and related metabolites.

DESIGN

Azoxymethane-treated C57BL/6 mice were exposed to cigarette smoke or clean air 2 hours per day for 28 weeks. Shotgun metagenomic sequencing and liquid chromatography mass spectrometry were parallelly performed on mice stools to investigate alterations in microbiota and metabolites. Germ-free mice were transplanted with stools from smoke-exposed and smoke-free control mice.

RESULTS

Mice exposed to cigarette smoke had significantly increased tumour incidence and cellular proliferation compared with smoke-free control mice. Gut microbial dysbiosis was observed in smoke-exposed mice with significant differential abundance of bacterial species including the enrichment of Eggerthella lenta and depletion of Parabacteroides distasonis and Lactobacillus spp. Metabolomic analysis showed increased bile acid metabolites, especially taurodeoxycholic acid (TDCA) in the colon of smoke-exposed mice. We found that E. lenta had the most positive correlation with TDCA in smoke-exposed mice. Moreover, smoke-exposed mice manifested enhanced oncogenic MAPK/ERK (mitogen-activated protein kinase/extracellular signal‑regulated protein kinase 1/2) signalling (a downstream target of TDCA) and impaired gut barrier function. Furthermore, germ-free mice transplanted with stools from smoke-exposed mice (GF-AOMS) had increased colonocyte proliferation. Similarly, GF-AOMS showed increased abundances of gut E. lenta and TDCA, activated MAPK/ERK pathway and impaired gut barrier in colonic epithelium.

CONCLUSION

The gut microbiota dysbiosis induced by cigarette smoke plays a protumourigenic role in CRC. The smoke-induced gut microbiota dysbiosis altered gut metabolites and impaired gut barrier function, which could activate oncogenic MAPK/ERK signalling in colonic epithelium.

Parabacteroides distasonis Properties Linked to the Selection of New Biotherapeutics

Dysbiotic microbiota is often associated with health issues including inflammatory bowel disease or ulcerative colitis. In order to counterbalance host disorder caused by an alteration in the gut composition, numerous studies have focused on identifying new biotherapeutic products (NBPs). Among the promising NBPs is Parabacteroides distasonis, a gut microbiota member part of the core microbiome that recently has received much attention due to the numerous beneficial properties it brings to its host. In this study, the properties linked to the selection of NBPs were screened in 14 unrelated P. distasonis strains, including resistance to gastric conditions, adherence (Caco-2 model), transepithelial resistance (Caco-2 model), and immunomodulation, on nontreated and LPS-stimulated cells (HT-29 and peripheral blood mononuclear cells (PBMCs)). This approach allowed for the identification of five strains that combined almost all the in vitro biotherapeutic properties tested. However, all the P. distasonis strains induced the overproduction of proinflammatory cytokines on PBMCs, which was counteracted by the overproduction of the anti-inflammatory cytokines. Among these five strains, two particularly retained our attention as a potential NBP, by showing strong health-promoting function, the lowest overproduction of proinflammatory cytokines on PBMCs, and no detrimental effect on the host.

Cyanidin-3-O-glucoside extracted from the Chinese bayberry (Myrica rubra Sieb. et Zucc.) alleviates antibiotic-associated diarrhea by regulating gut microbiota and down-regulating inflammatory factors in NF-κB pathway

Chinese bayberry has been used to treat diarrhea in China for more than 2,000 years, but the mechanism is not clear. Due to the extensive use of antibiotics, antibiotic-associated diarrhea (AAD) is becoming more and more common in clinic, but there is no effective drug for the treatment. The present study aimed to explore the therapeutic effect of Chinese bayberry on AAD for the first time, and explained the underlying mechanism from different aspects. The BALB/c mice model was established by intragastric administration of lincomycin (3 g/kg). Successfully modeled mice were treated with purified water, dried bayberry powder suspension (100 mg/kg), C3G suspension (40 mg/kg) and montmorillonite powder suspension (40 mg/kg), respectively. The changes of body weight, diarrhea index, diarrhea status score were recorded and calculated regularly. 16S rRNA gene sequencing, intestinal immunofluorescence and inflammatory factor detection were further performed. The treatment with dried bayberry powder suspension and C3G suspension could rapidly reduce the diarrhea score and diarrhea index, increase food intake and restore body weight gain. The gut microbiota richness and diversity were significantly increased after dried bayberry powder suspension and C3G suspension treatments, typically decreased bacterial genera Enterococcus and Clostridium senus stricto 1. In addition, intake of Chinese bayberry powder and C3G significantly decreased the level of p65 phosphorylation, and up-regulated the expression of intestinal tight junction protein claudin-1 and ZO-1. Chinese bayberry fruit had the effect of alleviating AAD, and C3G was supposed to play the predominant role. The mechanism was indicated to be related with restoring the homeostasis of gut microbiota, inhibiting the level of harmful bacteria and increasing the abundance of beneficial bacteria, down-regulating TNF-α, IL-6, and IL-12 factors to reduce inflammation, restoring intestinal tight junction proteins and reducing intestinal permeability.

In Silico Study of Cell Surface Structures of Parabacteroides distasonis Involved in Its Maintenance within the Gut Microbiota

The health-promoting Parabacteroides distasonis, which is part of the core microbiome, has recently received a lot of attention, showing beneficial properties for its host and potential as a new biotherapeutic product. However, no study has yet investigated the cell surface molecules and structures of P. distasonis that allow its maintenance within the gut microbiota. Moreover, although P. distasonis is strongly recognized as an intestinal commensal species with benefits for its host, several works displayed controversial results, showing it as an opportunistic pathogen. In this study, we reported gene clusters potentially involved in the synthesis of capsule, fimbriae-like and pili-like cell surface structures in 26 P. distasonis genomes and applied the new RfbA-typing classification in order to better understand and characterize the beneficial/pathogenic behavior related to P. distasonis strains. Two different types of fimbriae, three different types of pilus and up to fourteen capsular polysaccharide loci were identified over the 26 genomes studied. Moreover, the addition of data to the rfbA-type classification modified the outcome by rearranging rfbA genes and adding a fifth group to the classification. In conclusion, the strain variability in terms of external proteinaceous structure could explain the inter-strain differences previously observed of P. distasonis adhesion capacities and its potential pathogenicity, but no specific structure related to P. distasonis beneficial or detrimental activity was identified.

Combining fecal microbiome and metabolomics to reveal the disturbance of gut microbiota in liver injury and the therapeutic mechanism of shaoyao gancao decoction

Chemical liver injury is closely related to gut microbiota and its metabolites. In this study, we combined 16S rRNA gene sequencing, ¹H NMR-based fecal metabolomics and GC-MS to evaluate the changes in gut microbiota, fecal metabolites and Short-chain fatty acids (SCFAs) in CCl₄-induced liver injury in Sprague-Dawley rats, and the therapeutic effect of Shaoyao Gancao Decoction (SGD). The results showed that CCl₄-induced liver injury overexpressed CYP2E1, enhanced oxidative stress, decreased antioxidant enzymes (SOD, GSH), increased peroxidative products MDA and inflammatory responses (IL-6, TNF-α), which were ameliorated by SGD treatment. H&E staining showed that SGD could alleviate liver tissue lesions, which was confirmed by the recovered liver index, ALT and AST. Correlation network analysis indicated that liver injury led to a decrease in microbiota correlation, while SGD helped restore it. In addition, fecal metabolomic confirmed the PICRUSt results that liver injury caused disturbances in amino acid metabolism, which were modulated by SGD. Spearman’s analysis showed that liver injury disrupted ammonia transport, urea cycle, intestinal barrier and energy metabolism. Moreover, the levels of SCFAs were also decreased, and the abundance of Lachnoclostridium, Blautia, Lachnospiraceae_NK4A136_group, UCG-005 and Turicibacter associated with SCFAs were altered. However, all this can be alleviated by SGD. More importantly, pseudo germ-free rats demonstrated that the absence of gut microbiota aggravated liver injury and affected the efficacy of SGD. Taken together, we speculate that the gut microbiota has a protective role in the pathogenesis of liver injury, and has a positive significance for the efficacy of SGD. Moreover, SGD can treat liver injury by modulating gut microbiota and its metabolites and SCFAs. This provides useful evidence for the study of the pathogenesis of liver injury and the clinical application of SGD.

Integrating 16S rRNA gene sequencing and metabolomics to evaluate the association between gut microbiota and serum metabolites in patients with myositis

AIMS

Gut microbiota and metabolites have a profound impact on the maintenance of body health. In this study, we assessed the association between gut microbiota and serum metabolite changes in myositis using 16S rRNA gene sequencing and metabolomics to provide new ideas for screening and treating myositis.

METHODS AND RESULTS

Blood and fecal samples were collected from twenty myositis patients and twenty healthy control subjects. Then, 16S rRNA gene sequencing, enzyme-linked immunosorbent assays, and untargeted metabolomics study were performed to evaluate the relationship between gut microbiota and serum metabolites in patients with myositis. Compared to healthy control subjects, the blood samples from the patients with myositis had elevated levels of interleukin-4 (IL-4), tumor necrosis factor-α (TNF-α), and malondialdehyde (MDA), and decreased superoxide dismutase (SOD) levels. The increase in Bacteroidota (including Bacteroides and Parabacteroides, but not Prevotella) and the decrease in Firmicutes in the patients were accompanied by functional changes in amino acid and lipid metabolism. The gut microbiota (Bacteroides and Parabacteroides) were negatively correlated with the differential serum metabolites (glutamate and taurine). The differential serum metabolites (glutamate, pyrrolidonecarboxylic acid, and taurine) were also correlated with inflammatory factors (IL-4 and TNF-α) and oxidative stress indexes (MDA and SOD).

CONCLUSION

Dysbiosis of gut microbiota in patients with myositis was accompanied by changes in inflammatory factors, oxidative stress indexes, and small molecule metabolites in serum.

SIGNIFICANCE AND IMPACT OF STUDY

Blood and fecal biomarkers could be used for screening myositis.

The Tissue-Associated Microbiota in Colorectal Cancer: A Systematic Review

Simple Summary

Growing evidence shows a close relationship between the microbiome and colorectal cancer, but most studies analyze fecal samples. However, solid information on the microbial community that is present locally in the intestinal tumor tissues is lacking. Therefore, the aim of this systematic review was to compile evidence on the relationship between tissue-associated microbiota and colorectal cancer. Among 5080 screened publications, 39 were eligible and included in the analysis. Despite the heterogeneity in methodologies and reporting between studies, 12 groups of bacteria with strong positive and 18 groups of bacteria with strong negative associations with colorectal cancer were identified. Such knowledge may ultimately be used in novel strategies that aim to prevent, detect, and treat colorectal cancer in the upcoming years.

Abstract

The intestinal microbiome is associated with colorectal cancer. Although the mucosal microbiota better represents an individual’s local microbiome, studies on the colorectal cancer microbiota mainly reflect knowledge obtained from fecal samples. This systematic review aimed to summarize the current evidence on the relationship between the mucosal-associated bacterial microbiota and colorectal cancer. Searches were conducted in PubMed and Web of Science databases for publications comparing the mucosal microbiome of colorectal cancer patients with that of healthy controls, or with that of non-cancerous mucosal tissues. The primary outcomes were differences in microbial diversity and taxonomy. The Newcastle-Ottawa Scale was used to assess the quality of the included studies. Of the 5080 studies identified, 39 were eligible and included in the systematic review. No consistent results were identified for the α- and β-diversity, due to high heterogeneity in reporting and to differences in metrics and statistical approaches, limiting study comparability. Qualitative synthesis of microbial taxonomy identified 12 taxa with strong positive and 18 taxa with strong negative associations with colorectal cancer. Fusobacterium, Campylobacter, Parvimonas, Peptostreptococcus, Streptococcus, and Granulicatella were defined as enriched in colorectal cancer. Despite the methodological limitations of the studies, consistent evidence on bacterial taxa associated with colorectal cancer was identified. Prospective studies in large and well-characterized patient populations will be crucial to validate these findings.

Recombinant Bifidobacterium longum Carrying Endostatin Protein Alleviates Dextran Sodium Sulfate-Induced Colitis and Colon Cancer in Rats

Bifidobacterium has been widely administrated orally as probiotics to prevent pathogen colonization and modulate the gut microbiome balance. Endostatin is an endogenous inhibitor of angiogenesis and has been shown to inhibit tumor growth, invasion, and metastasis. At present, the combination of endostatin and chemotherapeutic drugs has been regarded as a promising antitumor treatment strategy. In this study, we selected a safe strain of Bifidobacterium longum as a delivery system to transport endostatin to the gastrointestinal tract and explored their combined effect on inflammatory bowel disease (IBD) and colitis-associated cancer. The results indicated that B. longum-Endo relieved dextran sulfate sodium-induced body weight loss, diarrhea, colon shortening, and epithelium damage. Long-term oral administration of B. longum-Endo significantly decreased tumor formation rate, tumor number, and tumor size. Moreover, the effect of B. longum-Endo on gut microbiota dysbiosis was also confirmed by 16S rRNA sequencing analysis. The levels of potentially beneficial bacteria, such as Lactobacillus, Bifidobacterium, Allobaculum, and Parabateroides, were increased in the B. longum-Endo group compared to the model and B. longum groups. Meanwhile, levels of potentially pathogenic bacteria including Desulfovibrio, Helicobacter, and Enterorhabdus were decreased. Taken together, these results suggested that oral administration of recombinant B. longum-Endo strain may be a promising therapeutic strategy for IBD and colitis-associated cancer.