Project description:Gut microbial dysbiosis can play a causal role of in colorectal cancer. Gut microbiota chnages with age and becomes moer pro-inflammatory. We sought to determine whether microbiota from Old donors promotes more tumor formation in recipients than meterial from young donors.
Project description:Gut microbial dysbiosis can play a causal role of in colorectal cancer. Gut microbiota chnages with age and becomes moer pro-inflammatory. We sought to determine whether microbiota from Old donors promotes more tumor formation in recipients than meterial from young donors.
Project description:Colorectal cancer is a leading cause of cancer-related deaths. Mutations in the innate immune receptor AIM2 are frequently identified in patients with colorectal cancer, but how AIM2 modulates colonic tumorigenesis is unknown. Here, we found that Aim2-deficient mice were hypersusceptible to colonic tumor development. Production of inflammasome-associated cytokines and other inflammatory mediators were largely intact in Aim2-deficient mice, however, intestinal stem cells were prone to uncontrolled proliferation. Aberrant Wnt signaling expanded a population of tumor-initiating stem cells in the absence of AIM2. Susceptibility of Aim2-deficient mice to colorectal tumorigenesis was enhanced by a dysbiotic gut microbiota, which was reduced by reciprocal exchange of gut microbiota with wild-type healthy mice. These findings uncover a synergy between a specific host genetic factor and gut microbiota in determining the susceptibility to colorectal cancer. Therapeutic modulation of AIM2 expression and microbiota has the potential to prevent colorectal cancer. We used microarrays to compare the transcriptome Aim2 deficent mice to wild type mice in colon tumor and colitis samples. Here were 12 mice in total, 3 for each genotype and tissue combination.
Project description:Chronic inflammation and gut microbiota dysbiosis are risk factors for colorectal cancer. In clinical practice, inflammatory bowel disease (IBD) patients have a greatly increased risk of developing colitis associated colorectal cancer (CAC). However, the basis underlying the initiation of CAC remains to be explored. Systematic filtration through existing genome-wide association study (GWAS) and conditional deletion of Zfp90 in CAC mice model indicated that Zfp90 was a putative oncogene in CAC development. Strikingly, depletion of gut microbiota eliminated the tumorigenic effect of Zfp90 in CAC mice model. Moreover, fecal microbiota transplantation demonstrated Zfp90 promoted CAC depending on gut microbiota. Combining 16s rDNA sequencing in feces specimens from CAC mice model, we speculated that Prevotella copri-defined microbiota might mediate the oncogenic role of Zfp90 in the development of CAC. Mechanistic studies revealed Zfp90 accelerated CAC development through Tlr4-Pi3k-Akt-Nf-κb pathway. Our findings elucidated the crucial role of Zfp90-microbiota-Nf-κb axis in creating a tumor-promoting environment and suggested therapeutic targets for CAC prevention and treatment.
Project description:<p>Emerging evidence that the gut microbiota may contribute in important ways to human health and disease has led us and others to hypothesize that both symbiotic and pathological relationships between gut microbes and their host may be key contributors to obesity and the metabolic complications of obesity. Our "Thrifty Microbiome Hypothesis" poses that gut microbiota play a key role in human energy homeostasis. Specifically, constituents of the gut microbial community may introduce a survival advantage to its host in times of nutrient scarcity, promoting positive energy balance by increasing efficiency of nutrient absorption and improving metabolic efficiency and energy storage. However, in the presence of excess nutrients, fat accretion and obesity may result, and in genetically predisposed individuals, increased fat mass may result in preferential abdominal obesity, ectopic fat deposition (liver, muscle), and metabolic complications of obesity (insulin resistance, hypertension, hyperlipidemia). Furthermore, in the presence of excess nutrients, a pathological transition of the gut microbial community may occur, causing leakage of bacterial products into the intestinal lymphatics and portal circulation, thereby inducing an inflammatory state, further aggravating metabolic syndrome traits and accelerating atherosclerosis. This pathological transition and the extent to which antimicrobial leakage occurs and causes inflammatory and other maladaptive sequelae of obesity may also be influenced by host factors, including genetics. In the proposed study, we will directly test the Thrifty Microbiome Hypothesis by performing detailed genomic and functional assessment of gut microbial communities in intensively phenotyped and genotyped human subjects before and after intentional manipulation of the gut microbiome. To address these hypotheses, five specific aims are proposed: (1) enroll three age- and sex-matched groups from the Old Order Amish: (i) 50 obese subjects (BMI > 30 kg/m2) with metabolic syndrome, (ii) 50 obese subjects (BMI > 30 kg/m2) without metabolic syndrome, and (iii) 50 non-obese subjects (BMI < 25 kg/m2) without metabolic syndrome and characterize the architecture of the gut microbiota from the subjects enrolled in this study by high-throughput sequencing of 16S rRNA genes; (2) characterize the gene content (metagenome) to assess the metabolic potential of the gut microbiota in 75 subjects to determine whether particular genes or pathways are correlated with disease phenotype; (3) characterize the transcriptome in 75 subjects to determine whether differences in gene expression in the gut microbiota are correlated with disease phenotype, (4) determine the effect of manipulation of the gut microbiota with antibiotics on energy homeostasis, inflammation markers, and metabolic syndrome traits in 50 obese subjects with metabolic syndrome and (5) study the relationship between gut microbiota and metabolic and cardiovascular disease traits, weight change, and host genomics in 1,000 Amish already characterized for these traits and in whom 500K Affymetrix SNP chips have already been completed. These studies will provide our deepest understanding to date of the role of gut microbes in terms of 'who's there?', 'what are they doing?', and 'how are they influencing host energy homeostasis, obesity and its metabolic complications? PUBLIC HEALTH RELEVANCE: This study aims to unravel the contribution of the bacteria that normally inhabit the human gastrointestinal tract to the development of obesity, and its more severe metabolic consequences including cardiovascular disease, insulin resistance and Type II diabetes. We will take a multidisciplinary approach to study changes in the structure and function of gut microbial communities in three sets of Old Order Amish patients from Lancaster, Pennsylvania: obese patients, obese patients with metabolic syndrome and non-obese individuals. The Old Order Amish are a genetically closed homogeneous Caucasian population of Central European ancestry ideal for genetic studies. These works have the potential to provide new mechanistic insights into the role of gut microflora in obesity and metabolic syndrome, a disease that is responsible for significant morbidity in the adult population, and may ultimately lead to novel approaches for prevention and treatment of this disorder.</p>
Project description:Colorectal cancer is a leading cause of cancer-related deaths. Mutations in the innate immune receptor AIM2 are frequently identified in patients with colorectal cancer, but how AIM2 modulates colonic tumorigenesis is unknown. Here, we found that Aim2-deficient mice were hypersusceptible to colonic tumor development. Production of inflammasome-associated cytokines and other inflammatory mediators were largely intact in Aim2-deficient mice, however, intestinal stem cells were prone to uncontrolled proliferation. Aberrant Wnt signaling expanded a population of tumor-initiating stem cells in the absence of AIM2. Susceptibility of Aim2-deficient mice to colorectal tumorigenesis was enhanced by a dysbiotic gut microbiota, which was reduced by reciprocal exchange of gut microbiota with wild-type healthy mice. These findings uncover a synergy between a specific host genetic factor and gut microbiota in determining the susceptibility to colorectal cancer. Therapeutic modulation of AIM2 expression and microbiota has the potential to prevent colorectal cancer.
Project description:Advanced age is associated with chronic low-grade inflammation, which is usually referred to as inflammaging. Elderly are also known to have an altered gut microbiota composition. However, whether inflammaging is a cause or consequence of an altered gut microbiota composition is not clear. In this study gut microbiota from young or old conventional mice was transferred to young germ-free mice. Four weeks after gut microbiota transfer immune cell populations in spleen, Peyer’s patches, and mesenteric lymph nodes from conventionalized germ-free mice were analyzed by flow cytometry. In addition, whole-genome gene expression in the ileum was analyzed by microarray. Gut microbiota composition of donor and recipient mice was analyzed with 16S rDNA sequencing. Here we show by transferring aged microbiota to young germ-free mice that certain bacterial species within the aged microbiota promote inflammaging. This effect was associated with lower levels of Akkermansia and higher levels of TM7 bacteria and Proteobacteria in the aged microbiota after transfer. The aged microbiota promoted inflammation in the small intestine in the germ-free mice and enhanced leakage of inflammatory bacterial components into the circulation was observed. Moreover, the aged microbiota promoted increased T cell activation in the systemic compartment. In conclusion, these data indicate that the gut microbiota from old mice contributes to inflammaging after transfer to young germ-free mice.
Project description:The study is based on the hypothesis that patients with postoperative anastomotic leakage have a different bacterial profile contributing to poor tissue healing, and that patients operated for colon cancer presumably have a different preoperative microbiota than healthy patients. This different composition is probably induced by the high heme level in the light intestinal tract that tumor spoliation generates.
The objective of the study is to evaluate the feasibility of a larger study to evaluate the difference between microbiota composition of patients with and without colorectal cancer, with inflammatory bowel disease and those with and without anastomotic leakage postoperatively of a colonic resection.
Stool samples will be taken from 20 patients, including 5 without intestinal pathology, 5 with colorectal cancer undergoing colorectal surgery, 5 with inflammatory bowel disease and 5 with anastomotic leakage after colectomy for colorectal cancer or inflammatory bowel disease.
The stool samples will be analyzed at CRCHUM to draw up a profile of the bacteria that make up the microbiota of each patient.
Project description:Increasing importance in the onset and progression from colonic adenomatous polyps (AP) to colorectal cancer (CRC) has been attributed to the gut microbiota and the oncometabolites they may produce. To comprehensively study the microbial spatial variations and role of microbiota in CRC progression, multiple niches from the gastrointestinal system have to be investigated. We collected saliva, tissue and stool samples from 61 patients, including 46 CRC patients and 15 AP patients, well matched in age and sex, who were undergoing surgery in 2018 at the Careggi University Hospital (Florence, Italy). For all samples and locations we surveyed microbial composition through 16S ribosomal RNA and metabolites using NMR, and compared them across tissues and disease state, also considering CRC TNM staging. Our result suggest the importance of microbiota communities and derived oncometabolites in CRC development. Such association can be a forerunner for future studies on CRC/AP management.
Project description:We have previously demonstrated that the gut microbiota can play a role in the pathogenesis of conditions associated with exposure to environmental pollutants. It is well accepted that diets high in fermentable fibers such as inulin can beneficially modulate the gut microbiota and lessen the severity of pro-inflammatory diseases. Therefore, we aimed to test the hypothesis that hyperlipidemic mice fed a diet enriched with inulin would be protected from the pro-inflammatory toxic effects of PCB 126.