Influence Of Gut Microbiome Research Articles

Influence of Gut Microbiome on Induction of Obesity

Obesity is considered as a multifactorial disease which depends on the complex interaction of host genetics, diet and other environmental factors. Specific alterations in gut microbiota can lead to obesity. There are a few organisms in the gut which have a great influence by the diet we eat. Organisms such as Actinobacteria, Firmicutes and Bacteriodetes are some of the common ones. The role of the gut microbiota in understanding the onset and development of obesity is gaining importance. This review covers the latest available data regarding the influence of different factors on gut microbiota in relation to obesity. Potential Therapeutic Targets and Probiotic Treatment –The gut bacteria model attributes obesity to the variable makeup of gut microbiota and its ability to modulate host energy homeostasis, adiposity and inflammation. To counteract these Student effects, strains of probiotics have been developed to manipulate gut microbiomes and improve health. This highlights recent human study data assessing the effects of probiotic supplementation on the prevention and treatment of obesity.Support or Funding InformationDr. Rajeev Pandey ‐ Department of Biochemistry, Spartan Health Sciences University, St. Lucia, West IndiesThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The 13th International Double-Stranded RNA Virus Symposium, Houffalize, Belgium, 24 to 28 September 2018.

The triennial International Double-Stranded RNA Virus Symposium, this year organized by J. Matthijnssens, J. S. L. Parker, P. Danthi, and P. Van Damme in Belgium, gathered over 200 scientists to discuss novel observations and hypotheses in the field. The keynote lecture on functional interactions of bacteria and viruses in the gut microbiome was presented by Julie Pfeiffer. Workshops were held on viral diversity, molecular epidemiology, molecular virology, immunity and pathogenesis, virus structure, the viral use and abuse of cellular pathways, and applied double-stranded RNA (dsRNA) virology. The establishment of a plasmid only-based reverse genetics system for rotaviruses by several Japanese research groups in 2017 has now been reproduced by various other research groups and was discussed in detail. The visualization of dsRNA virus replication steps in living cells received much attention. Mechanisms of the cellular innate immune response to virus infection and of viral pathogenesis were explored. Knowledge of the gut microbiome's influence on specific immune responses has increased rapidly, also due to the availability of relevant animal models of virus infection. The method of cryo-electron microscopic (cryo-EM) tomography has elucidated various asymmetric structures in viral particles. The use of orthoreoviruses for oncolytic virotherapy was critically assessed. The application of llama-derived single chain nanobodies for passive immunotherapy was considered attractive. In a satellite symposium the introduction, impact and further developments of rotavirus vaccines were reviewed. The Jean Cohen Lecturer of this meeting was Harry B. Greenberg, who presented aspects of his research on rotaviruses over a period of more than 40 years. He was also interviewed at the meeting by Vincent Racaniello for the 513th session of This Week in Virology.

Influence of gut microbiome on mucosal immune activation and SHIV viral transmission in naive macaques.

It is unknown whether the gut microbiome affects HIV transmission. In our recent SHIV vaccine study, we found that the naïve rhesus macaques from two different sources had significantly different rates of infection against repeated low-dose intrarectal challenge with SHIVSF162P4 virus. Exploring causes, we found that the more susceptible group of 7 macaques had significantly more activated CD4+CCR5+Ki67+ T cells in the rectal mucosa than the more resistant group of 11 macaques from a different source. The prevalence of pre-challenge activated rectal CD4 T cells in the naïve macaques correlated inversely with the number of challenges required to infect. Because the two naïve groups came from different sources, we hypothesized that their microbiomes may differ and might explain the activation difference. Indeed, after sequencing 16s rRNA, we found differences between the two naive groups that correlated with immune activation status. Distinct gut microbiota induced different levels of immune activation ex vivo. Significantly lower ratios of Bacteroides to Prevotella, and significantly lower levels of Firmicutes were found in the susceptible cohort, which were also inversely correlated with high levels of immune activation in the rectal mucosa. Thus, host-microbiome interactions might influence HIV/SIV mucosal transmission through effects on mucosal immune activation.

The Gut Microbiome and Obesity.

The gut microbiome consists of trillions of bacteria which play an important role in human metabolism. Animal and human studies have implicated distortion of the normal microbial balance in obesity and metabolic syndrome. Bacteria causing weight gain are thought to induce the expression of genes related to lipid and carbohydrate metabolism thereby leading to greater energy harvest from the diet. There is a large body of evidence demonstrating that alteration in the proportion of Bacteroidetes and Firmicutes leads to the development of obesity, but this has been recently challenged. It is likely that the influence of gut microbiome on obesity is much more complex than simply an imbalance in the proportion of these phyla of bacteria. Modulation of the gut microbiome through diet, pre- and probiotics, antibiotics, surgery, and fecal transplantation has the potential to majorly impact the obesity epidemic.

Chemopreventive Metabolites Are Correlated with a Change in Intestinal Microbiota Measured in A-T Mice and Decreased Carcinogenesis.

Intestinal microbiota play a significant role in nutrient metabolism, modulation of the immune system, obesity, and possibly in carcinogenesis, although the underlying mechanisms resulting in disease or impacts on longevity caused by different intestinal microbiota are mostly unknown. Herein we use isogenic Atm-deficient and wild type mice as models to interrogate changes in the metabolic profiles of urine and feces of these mice, which are differing in their intestinal microbiota. Using high resolution mass spectrometry approach we show that the composition of intestinal microbiota modulates specific metabolic perturbations resulting in a possible alleviation of a glycolytic phenotype. Metabolites including 3-methylbutyrolactone, kyneurenic acid and 3-methyladenine known to be onco-protective are elevated in Atm-deficient and wild type mice with restricted intestinal microbiota. Thus our approach has broad applicability to study the direct influence of gut microbiome on host metabolism and resultant phenotype. These results for the first time suggest a possible correlation of metabolic alterations and carcinogenesis, modulated by intestinal microbiota in A-T mice.

Enterohormones Down-Regulated in High-Fat Diet

Introduction: To investigate the role of microbes upon the regulation of enteroendocrine hormones. Methods: Germ-free and specific pathogen-free (SPF) mice were caged under a 12-hour light-dark cycle and fed a high- or low-fat diet for 10 weeks. Animals were then humanely anesthetized with a mixture of ketamine and xylazine. Then, ileal mucosal scrapes were collected for RNA. cDNA was synthesized and qRT-PCR was performed with GiP, PYY, CCK primers, and normalized to GAPDH as a housekeeping gene. Results: More than 1/3 of U.S. adults are obese, and evidence suggests that inappropriate responsiveness to the intestinal microbiome plays a role. Obesity is a multivariable disease resulting in prolonged imbalance of energy input and energy expenditure. Since evidence suggests that changes in the gut microbiome influence energy metabolism and play an important role in the pathogenesis of obesity, we hypothesized that microbes influence enteroendocrine hormones in the intesitne. CCK is produced by I cells, and was the first gut hormone identified to regulate appetite. GiP is produced by K cells and is an incretin that regulates fatty acid metabolism. PYY is produced by L cells and regulates appetite and gastric emptying. Our results show that CCK, GiP, and PYY expression is unchanged in germ-free animals regardless of the diet (high-fat vs low-fat). However, in SPF animals, high-fat diets significantly up-regulate CCK by twofold and GiP by three-fold compared with animals on low-fat diet. No changes were observed in PYY expression in SPF regardless of the diet. In addition, no diurnal patterns were observed when examining CCK or GIP in circadian time, suggesting feeding patterns do not drive the changes in expression. Conclusion: Under germ-free conditions, diet has no influence upon CCK, GiP, or PYY expression in the small intestine. In SPF mice, CCK and GiP are up-regulated in the ileum under high fat diet. It appears microbes are required for the dietary regulation of CCK and GiP expression. There is no circardian variation of CCK and GiP ileal expression in animals fed with high-fat versus low-fat diet. Therefore, the effect of the different diets is not due to diurnal variation. Our study will add to our mechanistic insight into the regulation of obesity by the microbiome and further elucidate how changes in the microbiome lead to obesity.

Human microbiomics

The sequencing of the human genome has driven the study of human biology in a significant way and enabled the genome-wide study to elucidate the molecular basis of complex human diseases. Recently, the role of microbiota on human physiology and health has received much attention. The influence of gut microbiome (the collective genomes of the gut microbiota) in obesity has been demonstrated, which may pave the way for new prophylactic and therapeutic strategies such as bacteriotherapy. The significance and recent understandings in the area of "human microbiomics" are discussed here.