The who, where and how of fusobacteria and colon cancer

Dietary tryptophan improves growth and intestinal health by promoting the secretion of intestinal β-defensins against enterotoxigenic E. coli F4 in weaned piglets

Adequate dietary L-tryptophan (Trp) governs intestinal homeostasis in piglets. However, the defensive role of Trp in the diet against enterotoxigenic E. coli F4 (K88) in pigs is still poorly understood. Here, sixty (6.15 ± 1.52 kg, 24-day-old, Duroc × Landrace × Yorkshire) weaned piglets were used for an E. coli F4 attack test in a 2 × 2 factorial design. The growth (ADG, ADFI, GH), immune factors (IL-10, IgA, IgG, IgM), Trp metabolite 5-HT, intestinal morphology (jejunal and colonic VH), mRNA expression of β-defensins (jejunal BD-127, BD-119, ileal BD-1, BD-127), and abundance of beneficial microorganisms in the colon (Prevotella 9, Lactobacillus, Phascolarctobacterium, Faecalibacterium) were higher in the piglets in the HT (High Trp) and HTK (High Trp, K88) groups than in the LT (Low Trp) and LTK (Low Trp, K88) groups (P < 0.05), while FCR, diarrhea rate, diarrhea index, serum Trp, Kyn, IDO, D-LA, ET, and abundance of harmful microorganisms in the colon (Spirochaetes, Fusobacteria, Prevotella, Christensenellaceae R7) were lower in the HT and HTK groups than in the LT and LTK groups (P < 0.05). High Trp reduced the expression of virulence genes (K88 and LT) after E. coli F4 attack (P < 0.05). The IL-6, TNF-α was lower in the HTK group than in the LT, LTK group (P < 0.05). In short, a diet containing 0.35% Trp protected piglets from enterotoxigenic E. coli F4 (K88) via Trp metabolism promoting BD expression in the intestinal mucosa, which improved growth and intestinal health.

Oncomicrobial Community Profiling Identifies Clinicomolecular and Prognostic Subtypes of Colorectal Cancer

BACKGROUND & AIMS

Dysbiosis of gut microbiota is linked to the development of colorectal cancer (CRC). However, microbiota-based stratification of CRC tissue and how this relates to clinicomolecular characteristics and prognosis remains to be clarified.

METHODS

Tumor and normal mucosa from 423 patients with stage I to IV CRC were profiled by bacterial 16S rRNA gene sequencing. Tumors were characterized for microsatellite instability (MSI), CpG island methylator phenotype (CIMP), APC, BRAF, KRAS, PIK3CA, FBXW7, SMAD4, and TP53 mutations, subsets for chromosome instability (CIN), mutation signatures, and consensus molecular subtypes (CMS). Microbial clusters were validated in an independent cohort of 293 stage II/III tumors.

RESULTS

Tumors reproducibly stratified into 3 oncomicrobial community subtypes (OCSs) with distinguishing features: OCS1 (Fusobacterium/oral pathogens, proteolytic, 21%), right-sided, high-grade, MSI-high, CIMP-positive, CMS1, BRAF V600E, and FBXW7 mutated; OCS2 (Firmicutes/Bacteroidetes, saccharolytic, 44%), and OCS3 (Escherichia/Pseudescherichia/Shigella, fatty acid β-oxidation, 35%) both left-sided and exhibiting CIN. OCS1 was associated with MSI-related mutation signatures (SBS15, SBS20, ID2, and ID7) and OCS2 and OCS3 with SBS18 related to damage by reactive oxygen species. Among stage II/III patients, OCS1 and OCS3 both had poorer overall survival compared with OCS2 for microsatellite stable tumors (multivariate hazard ratio [HR], 1.85; 95% confidence interval [CI], 1.15-2.99; P = .012; and HR, 1.52; 95% CI 1.01-2.29; P = .044, respectively) and left-sided tumors (multivariate HR, 2.66; 95% CI, 1.45-4.86; P = .002; and HR, 1.76; 95% CI, 1.03-3.02; P = .039, respectively).

CONCLUSIONS

OCS classification stratified CRCs into 3 distinct subgroups with different clinicomolecular features and outcomes. Our findings provide a framework for a microbiota-based stratification of CRC to refine prognostication and to inform the development of microbiota-targeted interventions.

Young-onset colorectal cancer

In the past decades the incidence of colorectal cancer (CRC) in people under the age of 50 years has increased, which is referred to as early-onset CRC or young-onset CRC (YO-CRC). YO-CRC is expected to account for 11% of colon cancers and 23% of rectal cancers by 2030. This trend is observed in different parts of the world and in both men and women. In 20% of patients with YO-CRC, a hereditary cancer syndrome is found as the underlying cause; however, in the majority of patients no genetic predisposition is present. Beginning in the 1950s, major changes in lifestyle such as antibiotic use, low physical activity and obesity have affected the gut microbiome and may be an important factor in YO-CRC development. Owing to a lack of screening, patients with YO-CRC are often diagnosed with advanced-stage disease. Long-term treatment-related complications should be taken into account in these younger patients, making the more traditional sequential approaches of drug therapy not always the most appropriate option. To better understand the underlying mechanism and define relationships between environmental factors and YO-CRC development, long-term prospective studies are needed with lifestyle data collected from childhood.

Association of Gut Microbiota and Biochemical Features in a Chinese Population With Renal Uric Acid Stone

Previous studies suggest that patients with nephrolithiasis exhibit dysbiosis in their gut microbiota, but those studies were conducted in calcium oxalate stone patients. We aimed to explore the association of gut microbiota and biochemical features of renal uric acid stone (UAS) patients in a Chinese population and identify the related bacteria that may affect the pathopoiesis of UAS. A case-control study of 117 patients with UAS, 123 patients with gout, and 135 healthy controls were included from January 2014 to October 2020. For each subject, data on demographics, biochemical parameters of blood and urine were analyzed. Fifteen patients with gout, 16 patients with UAS, 17 UAS patients with gout, and 17 healthy subjects were enrolled and provided fecal samples. The characteristics of gut microbiota were explored by using 16S ribosomal RNA (rRNA) gene sequencing and analyzed by using a combination of software mother and R. Hyperuricemia was the main risk factor for the development of gout and UAS. Obesity, dyslipidemia, and aciduria were unique risk factors for UAS patients. The richness, diversity, and relative abundance of dominant bacteria at the phylum and genus levels of gut microbiota in UAS patients were significantly distinct from other subjects. Abundance of Bacteroides and Fusobacterium was significantly positively correlated with the serum uric acid (UA) level of UAS patients. Fusobacteria was involved in the metabolism and degradation of certain short-chain fatty acids, amino acids, and sugars in pathopoiesis of UAS, and inhibited their synthesis pathways. Fusobacteria may be related to the pathogenesis of UAS, and this finding contributes to the personalized treatment of UAS from the perspective of maintaining micro-ecological equilibrium in gut.

Creutzfeldt-Jakob Disease: Alterations of Gut Microbiota

Introduction

Human gut dysbiosis has been implicated with the onset of many neurodegenerative disorders. However, the current data focused on the gut microbiota of patients with Creutzfeldt-Jakob disease (CJD) are still lacking. In our study, we explored the gut microbiota alteration in patients with CJD.

Method

We performed 16S ribosomal RNA MiSeq sequencing in stool samples of patients with CJD and controls. Functional analysis of the gut microbiota between these two groups was based on Kyoto Encyclopedia of Genes and Genomes and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States 2. Clinical rating scales were used to evaluate the association between cognitive impairment and gut microbiota alteration.

Result

We identified a significant alteration in both the structure and the richness of the CJD group. Function analysis revealed that the gut microbiota of patients with CJD enriched in immune signaling molecule interactions and xenobiotics biodegradation. MoCA and survival times were found to be associated with gut microbiota in patients with CJD.

Conclusion

We demonstrated an altered gut microbiota in patients with CJD, which was associated with the cognitive impairment and the survival time of these patients.

The gut microbiome in sickle cell disease: Characterization and potential implications

BACKGROUND

Sickle Cell Disease (SCD) is an inherited blood disorder that leads to hemolytic anemia, pain, organ damage and early mortality. It is characterized by polymerized deoxygenated hemoglobin, rigid sickle red blood cells and vaso-occlusive crises (VOC). Recurrent hypoxia-reperfusion injury in the gut of SCD patients could increase tissue injury, permeability, and bacterial translocation. In this context, the gut microbiome, a major player in health and disease, might have significant impact. This study sought to characterize the gut microbiome in SCD.

METHODS

Stool and saliva samples were collected from healthy controls (n = 14) and SCD subjects (n = 14). Stool samples were also collected from humanized SCD murine models including Berk, Townes and corresponding control mice. Amplified 16S rDNA was used for bacterial composition analysis using Next Generation Sequencing (NGS). Pairwise group analyses established differential bacterial groups at many taxonomy levels. Bacterial group abundance and differentials were established using DeSeq software.

RESULTS

A major dysbiosis was observed in SCD patients. The Firmicutes/Bacteroidetes ratio was lower in these patients. The following bacterial families were more abundant in SCD patients: Acetobacteraceae, Acidaminococcaceae, Candidatus Saccharibacteria, Peptostreptococcaceae, Bifidobacteriaceae, Veillonellaceae, Actinomycetaceae, Clostridiales, Bacteroidacbactereae and Fusobacteriaceae. This dysbiosis translated into 420 different operational taxonomic units (OTUs). Townes SCD mice also displayed gut microbiome dysbiosis as seen in human SCD.

CONCLUSION

A major dysbiosis was observed in SCD patients for bacteria that are known strong pro-inflammatory triggers. The Townes mouse showed dysbiosis as well and might serve as a good model to study gut microbiome modulation and its impact on SCD pathophysiology.

T-cell immunoglobulin and ITIM domain, as a potential immune checkpoint target for immunotherapy of colorectal cancer

The importance of the tumor microenvironment in cancer progression has been well studied for many years. Immune checkpoint inhibitors (ICIs) are regarded as potential strategies in enhancing the immune responses in patients with cancer, particularly colorectal cancer (CRC). Notably, CRCs are extraordinarily heterogeneous and mostly are microsatellite-stable (MSS) or cold tumors, which means that the immune response is not usually as strong as that of foreign cells. T-cell immunoglobulin and ITIM domain (TIGIT) is a new immune checkpoint receptor overexpressed inside the CRC tumor-immune microenvironments. Moreover, several studies have shown that TIGIT in combination with other ICIs and/or conventional treatments, can lead to a robust anti-tumor response in CRC. This review looks deep inside TIGIT expression patterns, their various functions, and possible immunotherapy strategies to increase survival rates and decrease immune-related adverse events.

The fermented soy beverage Q-CAN® plus induces beneficial changes in the oral and intestinal microbiome

Background

Soy products are associated with many beneficial health consequences, but their effects on the human intestinal microbiome are poorly characterized.

Objectives

To identify the changes in the oral and fecal microbiome in lean and obese participants due to consumption of Q-CAN®, and to assess the expected consequences of these changes based on the published literature.

Methods

Prospective study of lean (10) and obese (9) participants consuming Q-CAN® twice daily for 4 weeks with 8 weeks follow-up. Microbial DNA was extracted from saliva and stool samples, amplified against the V4 region of the 16S ribosomal RNA gene and data analyzed using QIIME 1.9.1 bioinformatics. Four hundred forty-four samples were collected in total, 424 of which were productive and yielded good quality data.

Results

STOOL. In the lean population Bifidobacteria and Blautia show a significant increase while taking Q-CAN®, and there was a trend for this in the obese population. ORAL. There were relatively fewer major changes in the oral microbiome with an increase in the family Veillonellaceae in the lean population while on Q-CAN®.

Conclusion

Q-CAN® consumption induced a number of significant changes in the fecal and oral microbiome. Most notably an increase in the stool microbiome of Bifidobacteria and Blautia, both of which are associated with positive health benefits, and in the saliva an increase in Veillonellaceae.

Trial registration

This trial was registered with Clinicaltrials.gov on January 14th 2016.

ClinicalTrials.gov Identifier: NCT02656056

Supplementary Information

The online version contains supplementary material available at 10.1186/s40795-021-00408-4.

Modulating the microbiome to improve therapeutic response in cancer

Although novel therapies, including immunotherapy, have dramatically improved outcomes for many patients with cancer, overall outcomes are heterogeneous and existing biomarkers do not reliably predict response. To date, predictors of response to cancer therapy have largely focused on tumour-intrinsic features; however, there is growing evidence that other host factors (eg, host genomics and the microbiome) can substantially affect therapeutic response. The microbiome, which refers to microbiota within a host and their collective genomes, is becoming increasingly recognised for its influence on host immunity, as well as therapeutic responses to cancer treatment. Importantly, microbiota can be modified via several different strategies, affording new angles in cancer treatment to improve outcomes. In this Review, we examine the evidence on the role of the microbiome in cancer and therapeutic response, factors that influence and shape host microbiota, strategies to modulate the microbiome, and present key unanswered questions to be addressed in ongoing and future research.

An Early Fecal Microbiota Transfer Improves the Intestinal Conditions on Microflora and Immunoglobulin and Antimicrobial Peptides in Piglets

The goal of this study was to investigate the effects of early fecal microbial transfer (FMT) on the microflora of recipient piglets, where Yorkshire newborn piglets and Min sows (an indigenous pig breed in China) were used as the fecal recipients and donors, respectively, to reveal the changes in immunity and development-related functions of the intestinal mucosa driven by FMT. The recipient group was inoculated with fecal microbial fluids from days 1 to 10. On day 21, the relative abundance of the Proteobacteria was reduced; the concentrations of immunoglobulin M (IgM) and immunoglobulin G (IgG) in the jejunal mucosa, and that of IgG in the ileal mucosa of the recipient group, were increased (P < 0.05). On day 40, the relative abundance of the Firmicutes in the recipient group was increased, while that of Bacteroides was decreased. The concentrations of IgG and IgM in the ileal mucosa of the recipient group were increased. FMT protected the intestine by modulating the antimicrobial peptides of the intestinal mucosa (P < 0.05). The results of this study revealed that early FMT can improve the gut microbiota, intestinal mucosal immunity, and intestinal development-related functions of Yorkshire piglets.

Human Lung Microbiome on the Way to Cancer

Recent research on cancer-associated microbial communities led to the accumulation of data on the interplay between bacteria, immune and tumor cells, the pathways of bacterial induction of carcinogenesis, and its meaningfulness for medicine. Microbial communities that have any kind of impact on tumor progression and microorganisms associated with tumors have been defined as oncobiome. Over the last decades, a number of studies were dedicated to Helicobacter pylori and its role in the progression of stomach tumors, so this correlation can be regarded as proven. Involvement of bacteria in the induction of lung cancer has been largely ignored for a long time, though some correlations between this type of cancer and lung microbiome were established. Despite the fact that in the present the microbial impact on lung cancer progression has many confirmations, the underlying mechanisms are poorly understood. Microorganisms can contribute to tumor initiation and progression through production of bacteriotoxins and other proinflammatory factors. The purpose of this review is to organize the available data on lung cancer microbiome and its role in malignant tumor progression.

Autoinducer-2 of Fusobacterium nucleatum promotes macrophage M1 polarization via TNFSF9/IL-1β signaling

The effect of Fusobacterium nucleatum (F. nucleatum) autoinducer-2 (AI-2) on the polarization of macrophages and the underlying mechanism is not known. We investigated the effect of F. nucleatum AI-2 on the migration and polarization of cultured macrophages. We further screened AI-2-interacting proteins in macrophages using a quantitative proteomics strategy, and evaluated the expression of TNFSF9/TRAF1/p-AKT/IL-1β signaling in cultured macrophages and human colorectal cancer (CRC). The data showed that F. nucleatum AI-2 enhanced the mobility and M1 polarization of macrophages, possibly through TNFSF9/TRAF1/p-AKT/IL-1β signaling. Moreover, TNFSF9 and IL-1β expression was significantly increased in human CRCs when compared to normal colon (P < 0.05), and was associated with AI-2 concentration and increased survival. Together, our data suggested that AI-2 induced macrophage M1 polarization by activating the TNFSF9/IL-1β pathway. Thus, AI-2 may serve as a promising novel target for immunotherapy of gut microbiota-related diseases.

Autoinducer-2 of gut microbiota, a potential novel marker for human colorectal cancer, is associated with the activation of TNFSF9 signaling in macrophages

Objectives: The interaction between the quorum sensing (QS) molecules of gut microbiota and the immunity of colorectal cancer (CRC) has not been investigated before. Methods: We measured the concentration of autoinducer-2 (AI-2) in samples of stool, colorectal tissue, saliva and serum of CRC patients, and compared this to AI-2 levels in colorectal adenoma (AD) and normal colon mucosa (NC). To explore the activated signaling pathways involved, we utilized AI-2 extracted from Fusobacterium nucleatum to stimulate macrophages and validated these in vitro findings in human CRC tissues. Results: The AI-2 concentration in both colorectal tissue and stool of CRC patients was significantly higher when compared to that in AD and NC (all P values < .01). The AI-2 concentration along with the progression of CRC in both tissues and stools was significantly increased (P= .045，P= .0003, respectively). After AI-2 stimulation, TNFSF9 was the most significantly increased protein in macrophage cells (P < .01). TNFSF9 expression was significantly higher in CRC tissues when compared to NCs (P< .0001), which was mainly derived from macrophages in the tumor microenvironment. Moreover, AI-2 level was positively associated with CD3 + T cell numbers (P= .0462), and negatively associated with CD4/CD8 ratio (P= .0113) within CRC tissues. Conclusions: We demonstrated for the first time that AI-2 may serve as a novel marker for screening CRC in the clinic. AI-2 was associated with tumor immunity in CRCs through tumor-associated macrophages and CD4/CD8 ratio in a TNFSF9-dependent manner.

Fusobacterium nucleatum Contributes to the Carcinogenesis of Colorectal Cancer by Inducing Inflammation and Suppressing Host Immunity

The presence of Fusobacterium nucleatum (F. nucleatum) in the gut is associated with the development of colorectal cancer (CRC). F. nucleatum promotes tumor development by inducing inflammation and host immune response in the CRC microenvironment. Adhesion to the intestinal epithelium by the cell surface proteins FadA, Fap2 and RadD expressed by F. nucleatum can cause the host to produce inflammatory factors and recruit inflammatory cells, creating an environment which favors tumor growth. Furthermore, F. nucleatum can induce immune suppression of gut mucosa by suppressing the function of immune cells such as macrophages, T cells and natural killer cells, contributing the progression of CRC.

Microbiome Dependent Regulation of Tregs and Th17 Cells in Mucosa

Mammals co-exist with resident microbial ecosystem that is composed of an incredible number and diversity of bacteria, viruses and fungi. Owing to direct contact between resident microbes and mucosal surfaces, both parties are in continuous and complex interactions resulting in important functional consequences. These interactions govern immune homeostasis, host response to infection, vaccination and cancer, as well as predisposition to metabolic, inflammatory and neurological disorders. Here, we discuss recent studies on direct and indirect effects of resident microbiota on regulatory T cells (T_regs) and Th17 cells at the cellular and molecular level. We review mechanisms by which commensal microbes influence mucosa in the context of bioactive molecules derived from resident bacteria, immune senescence, chronic inflammation and cancer. Lastly, we discuss potential therapeutic applications of microbiota alterations and microbial derivatives, for improving resilience of mucosal immunity and combating immunopathology.

Gut Microbiota, Fusobacteria, and Colorectal Cancer

The gut microbiota has emerged as an environmental contributor to colorectal cancer (CRC) in both animal models and human studies. It is now generally accepted that bacteria are ubiquitous colonizers of all exposed human body surfaces, including the entire alimentary tract (5). Recently, the concept that a normal bacterial microbiota is essential for the development of inflammation-induced carcinoma has emerged from studies of well-known colonic bacterial microbiota. This review explores the evidence for a role of fusobacteria, an anaerobic gram-negative bacterium that has repeatedly been detected at colorectal tumor sites in higher abundance than surrounding histologically normal tissue. Mechanistic studies provide insight on the interplay between fusobacteria, other gut microbiota, barrier functions, and host responses. Studies have shown that fusobacteria activate host inflammatory responses designed to protect against pathogens that promote tumor growth. We discuss how future research identifying the pathophysiology underlying fusobacteria colon colonization during colorectal cancer may lead to new therapeutic targets for cancer. Furthermore, disease-protective strategies suppressing tumor development by targeting the local tumor environment via bacteria represent another exciting avenue for researchers and are highlighted in this review.