Human gut metagenome
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PROVIDER: PRJNA284919 | ENA |
REPOSITORIES: ENA
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Project description:The mechanisms underlying Roux-en-Y gastric bypass (RYGB) surgery-induced weight loss and the immediate postoperative beneficial metabolic effects associated with the operation remain uncertain. We aimed to identify novel gut-derived peptides with therapeutic potential in obesity and/or diabetes by determining genome-wide expression patterns in isolated human small intestinal enteroendocrine cells (EECs) obtained from 20 obese subjects undergoing RYGB and again three months later by upper enteroscopy. RYGB increased expression levels of the inverse ghrelin receptor agonist, liver-enriched antimicrobial peptide 2 (LEAP2), and a secreted endogenous LEAP2 fragment (LEAP238-47) demonstrated insulinotropic properties in vitro, promoting an increase in insulin release comparable to the gut hormone glucagon-like peptide 1. LEAP238-47 showed reciprocal effects on growth hormone secretagogue receptor (GHSR) activity, suggesting that the insulinotropic action of the peptide may be directly linked to attenuation of tonic GHSR activity. The fragment was infused to healthy human individuals, but compared to placebo, no glucoregulatory effect was observed in the chosen dose. In conclusion, small intestinal LEAP2 expression was upregulated after RYGB; and the fragment LEAP238-47 showed a strong in vitro insulinotropic effect, but failed to elicit glucoregulatory effects when infused in healthy human subjects.
2020-11-18 | GSE154306 | GEO
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>
| phs000258 | dbGaP
Project description:In this study we demonstrate that the DNA methylation status in both blood and adipose tissue is highly associated to gut microbiota composition in obese subjects
2019-06-07 | GSE131461 | GEO
Project description:Hepatic lipid accumulation is an important complication of obesity linked to risk for type 2 diabetes. To identify novel transcriptional changes in human liver which could contribute to hepatic lipid accumulation and associated insulin resistance and type 2 diabetes (DM2), we evaluated gene expression and gene set enrichment in surgical liver biopsies from 13 obese (9 with DM2) and 5 control subjects, obtained in the fasting state at the time of elective abdominal surgery for obesity or cholecystectomy. RNA was isolated for cRNA preparation and hybridized to Affymetrix U133A microarrays. Human liver samples were obtained from 5 lean control subjects undergoing elective cholecystectomy and 13 obese subjects (with or without Type 2 diabetes) undergoing gastric bypass surgery. Subjects with diabetes were classified as either well-controlled or poorly-controlled.
2009-06-01 | E-GEOD-15653 | biostudies-arrayexpress
Project description:Gut microbiota dysbiosis characterizes systemic metabolic alteration, yet its causality is debated. To address this issue, we transplanted antibiotic-free conventional wild-type mice with either dysbiotic (“obese”) or eubiotic (“lean”) gut microbiota and fed them either a NC or a 72%HFD. We report that, on NC, obese gut microbiota transplantation reduces hepatic gluconeogenesis with decreased hepatic PEPCK activity, compared to non-transplanted mice. Of note, this phenotype is blunted in conventional NOD2KO mice. By contrast, lean microbiota transplantation did not affect hepatic gluconeogenesis. In addition, obese microbiota transplantation changed both gut microbiota and microbiome of recipient mice. Interestingly, hepatic gluconeogenesis, PEPCK and G6Pase activity were reduced even once mice transplanted with the obese gut microbiota were fed a 72%HFD, together with reduced fed glycaemia and adiposity compared to non-transplanted mice. Notably, changes in gut microbiota and microbiome induced by the transplantation were still detectable on 72%HFD. Finally, we report that obese gut microbiota transplantation may impact on hepatic metabolism and even prevent HFD-increased hepatic gluconeogenesis. Our findings may provide a new vision of gut microbiota dysbiosis, useful for a better understanding of the aetiology of metabolic diseases. all livers are from NC-fed mice only.
2017-03-16 | GSE81318 | GEO
Project description:Distal gut bacteria play a pivotal role in the digestion of dietary polysaccharides by producing a large number of carbohydrate-active enzymes (CAZymes) that the host otherwise does not produce. We report here the design of a high density custom microarray that we used to spot non-redundant DNA probes for more than 6,500 genes encoding glycoside hydrolases and lyases selected from 174 reference genomes from distal gut bacteria. The custom microarray was tested and validated by the hybridization of bacterial DNA extracted from the stool samples of lean, obese and anorexic individuals. Our results suggest that a microarray-based study can detect genes from low-abundance bacteria better than metagenomic-based studies. A striking example was the finding that a gene encoding a GH6-family cellulase was present in all subjects examined, whereas metagenomic studies have consistently failed to detect this gene in both human and animal gut microbiomes. In addition, an examination of eight stool samples allowed the identification of a corresponding CAZome core containing 46 families of glycoside hydrolases and polysaccharide lyases, which suggests the functional stability of the gut microbiota despite large taxonomical variations between individuals. Fecal samples were collected from eight female subjects. Three were obese subjects of BMI kg m-2: 35, 46.8 and 51.3, respectively; age: 42, 21 and 65 years old, respectively. Three were anorexic women of BMI kg m-2: 9.8, 10 and 13.7, respectively; age: 19, 23 and 49 years old, respectively. Finally, two fecal samples from lean women of BMI kg m-2: 18.6 and 23.42 were analyzed.
2013-10-28 | E-GEOD-51760 | biostudies-arrayexpress
Project description:Background & Aims: Bariatric surgery is associated with improved outcomes in subjects with severe obesity. We aimed to determine the prognostic relevance of liver histology in a large cohort of obese patients undergoing bariatric surgery. Methods: In a single center cohort of 492 subjects undergoing Roux-en-Y gastric bypass bariatric surgery with routine perioperative liver biopsy at Geneva University Hospital between January 1997 to December 2004, clinical and histopathological variables were analyzed for association with overall survival. Survival of the cohort was compared to age- and sex-matched life tables from the Swiss general population and propensity score-matched subjects from the third National Health and Nutrition Examination Survey (NHANES III). A 32-gene signature was evaluated in the liver tissue of 47 non-alcoholic steatohepatitis (NASH) subjects. Results: Median body mass index was 43.6 kg/m2. Twenty-one patients (4.2%) died during a median follow-up of 10.3 years. At baseline liver histology, 12% and 16% of subjects had NASH, and fibrosis, respectively. In multivariable Cox regression, presence of NASH (hazard ratio [HR] 3.4, p=0.0087), age greater than 50 years (HR 2.7, p=0.044), hypertension (HR 3.8, p=0.021), and short-term postoperative complications (HR 2.8, p=0.048) were associated with overall survival. Compared to matched NHANES III subjects, bariatric surgery improved long-term survival (HR 0.54, p=0.035), although this benefit was not observed in the subgroup of NASH patients (HR 0.97, p=0.94). A 32-gene poor prognosis signature prediction was associated with worse overall survival within NASH subjects (n=47, HR = 7.7, p=0.03 ). Conclusions Histologically proven NASH was associated with increased long-term mortality in subjects undergoing bariatric surgery. Although survival benefit of bariatric surgery may be limited in obese patients with NASH, a 32-gene expression signature appears to predict long term mortality in these patients.
2015-12-07 | GSE69248 | GEO
Project description:To compare the similarities and differences in species diversity of the gut microbiota between the patients with melasma and healthy subjects. The feces were collected for 16S rRNA sequencing analysis of the gut microbiota.
2022-10-25 | GSE214430 | GEO
Project description:Irritable Bowel Syndrome (IBS) is a disorder of the gut-brain axis, characterized by altered gut function and frequent psychiatric co-morbidity. Although altered intestinal microbiome profiles have been documented, their relevance to the clinical expression of IBS is unknown. To evaluate a functional role of the microbiota, we colonized germ-free mice with fecal microbiota from healthy controls or IBS patients with accompanying anxiety, and monitored gut function and behavior. Mouse microbiota profiles clustered according to their human donors. Despite having taxonomically similar composition as controls, mice with IBS microbiota had distinct serum metabolomic profiles related to neuro- and immunomodulation. Mice with IBS, but not control microbiota, exhibited faster gastrointestinal transit, intestinal barrier dysfunction, innate immune activation and anxiety-like behavior. These results support the notion that the microbiota contributes to both intestinal and behavioral manifestations of IBS and rationalize the use of microbiota-directed therapies in ameliorating IBS.
2017-03-02 | GSE61841 | GEO
Project description:Obesity is a risk factor for numerous metabolic disorders; however, not all obese individuals are prone to insulin resistance. The central aim of this study was to identify molecular pathways directly related to insulin resistance independent of BMI in obesity. We sought to determine the gene expression signature of adipose tissue in a body mass index (BMI)-matched obese cohort of patients that are either insulin sensitive or insulin resistant. We determined the global gene expression signatures of omental and subcutaneous adipose tissue samples obtained from insulin-sensitive obese and insulin-resistant obese patients undergoing gastric bypass surgery.
2009-04-24 | E-GEOD-15773 | biostudies-arrayexpress