FXR Agonism with Bile Acid Mimetic Reduces Pre-Clinical Triple-Negative Breast Cancer Burden
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE263255 | GEO | 2024/04/04
REPOSITORIES: GEO
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Project description:The inter-organ cross talk between liver and intestine has been focus of intense research. Key in this cross-talk are bile acids, which are secreted from the liver into the intestine and, via the enterohepatic circulation, reach back to the liver. Important new insights have been gained in the Farnesoid X receptor (Fxr)-mediated communication from intestine-to-liver in health and disease. However, liver-to-intestine communication and the role of bile acids and FXR in this cross talk remain elusive. Here, we analyse Fxr-mediated liver-to-gut communication, and its consequences in the colon. Mice in which Fxr was selectively ablated in intestine (Fxr-intKO), the liver (Fxr-livKO), or in the full body (Fxr-totKO) were engineered. The effects on colonic gene expression (RNA sequencing), on the microbiome (16S rRNA Gene Sequencing) and on mucus barrier were analyzed. Compared to Fxr-intKO and Fxr-totKO mice, more genes were differentially expressed in the colons of Fxr-livKO mice relative to control mice (731, 1824 and 3272 respectively), suggestive of a strong role of hepatic Fxr in liver-to-gut communication. The colons of Fxr-livKO showed increased expression of anti-microbial genes, such as Regenerating islet-derived 3 beta and gamma (Reg3β and Reg3γ), Toll-like receptors (Tlrs), inflammasome related genes and differential expression of genes belonging to the ‘Mucin-type O-glycan biosynthesis’ pathway. Compared to control mice, Fxr-livKO mice have decreased levels of the predicted mucin degrading bacterium Turicibacter and a concomitant increase in the thickness of the inner sterile mucus layer. In conclusion, ablation of Fxr in the liver has a major effect on colonic gene expression, the gut microbiome and on the permeability of the mucus layer. This stresses the importance of the Fxr-mediated liver-to-gut signaling.
2021-09-29 | GSE163157 | GEO
Project description:Morphine and its pharmacological derivatives are the most prescribed analgesics for moderate to severe pain management. However, chronic use of morphine reduces pathogen clearance and induces bacterial translocation across the gut barrier. The enteric microbiome has been shown to play a critical role in the preservation of the mucosal barrier function and metabolic homeostasis. Here, we show for the first time, using bacterial 16s rDNA sequencing, that chronic morphine treatment significantly alters the gut microbial composition and induces preferential expansion of the gram-positive pathogenic and reduction of bile-deconjugating bacterial strains. A significant reduction in both primary and secondary bile acid levels was seen in the gut, but not in the liver with morphine treatment. Morphine induced microbial dysbiosis and gut barrier disruption was rescued by transplanting placebo-treated microbiota into morphine-treated animals, indicating that microbiome modulation could be exploited as a therapeutic strategy for patients using morphine for pain management. In this study, we establish a link between the two phenomena, namely gut barrier compromise and dysregulated bile acid metabolism. We show for the first time that morphine fosters significant gut microbial dysbiosis and disrupts cholesterol/bile acid metabolism. Changes in the gut microbial composition is strongly correlated to disruption in host inflammatory homeostasis13,14 and in many diseases (e.g. cancer/HIV infection), persistent inflammation is known to aid and promote the progression of the primary morbidity. We show here that chronic morphine, gut microbial dysbiosis, disruption of cholesterol/bile acid metabolism and gut inflammation; have a linear correlation. This opens up the prospect of devising minimally invasive adjunct treatment strategies involving microbiome and bile acid modulation and thus bringing down morphine-mediated inflammation in the host.
2016-06-01 | E-MTAB-3722 | biostudies-arrayexpress
Project description:Deoxycholic acid (DCA) is a secondary bile acid produced by a small number of commensal species of bacteria present in the mammalian gut. Elevated DCA concentration correlates with disease states including colon cancer and cholesterol gallstones, but the associated mechanisms are not fully understood. Both primary and secondary bile acids are also capable of affecting gene expression through nuclear receptors such as FXR. To better understand the impact of a commensal-derived secondary bile acid on host metabolism we fed DCA to germ-free (GF) mice, which normally lack DCA, and compared the hepatic transcriptomes of bile acid fed GF mice to GF mice receiving a control diet, as well as to those of conventionally housed control animals. Interestingly, the feeding of DCA to GF mice, but not the feeding of cholic acid (CA) from which DCA is derived, results in an up-regulation of genes of cholesterol biosynthetic pathways. GF mice normally have elevated hepatic cholesterol compared to conventionally housed mice. Despite increase in the expression of cholesterol biosynthetic genes, the DCA fed GF mice showed a markedly decreased level of hepatic cholesterol equivalent to the hepatic cholesterol concentration of conventionally colonized animals. Total cholesterol in the serum was unaffected by DCA, but there was a decrease in the HDL lipoprotein fraction as well as an increase in the non-HDL lipoprotein fraction of the serum cholesterol. DCA, but not CA, is sufficient to modulate host lipoprotein metabolism. Taken together, these results suggests that a minor component of the gut microbiome has a significant impact on cholesterol homeostasis through secondary metabolism of bile acids and suggests a possible therapeutic intervention route through the microbial metabolic pathways. two mouse strains, three diets, one time point
2015-01-08 | E-GEOD-34730 | biostudies-arrayexpress
Project description:Microbial transformation of bile acids affects intestinal immune homeostasis but its impact on inflammatory pathologies remains largely unknown. Using a mouse model of graft-versus-host disease (GVHD), we found that T cell-driven inflammation decreased the abundance of microbiome-encoded bile salt hydrolase (BSH) genes and reduced the levels of unconjugated and microbe-derived bile acids. Several microbe-derived bile acids attenuated farnesoid X receptor (FXR) activation, suggesting that loss of these metabolites during inflammation may increase FXR activity and exacerbate the course of disease. Indeed, mortality increased with pharmacological activation of FXR and decreased with its genetic ablation in donor T cells during mouse GVHD. Furthermore, patients with GVHD after allogeneic hematopoietic cell transplantation showed similar loss of BSH and the associated reduction in unconjugated and microbe-derived bile acids. Additionally, the FXR antagonist ursodeoxycholic acid reduced the proliferation of human T cells and was associated with a lower risk of GVHD-related mortality in patients. We propose that dysbiosis and loss of microbe-derived bile acids during inflammation may be an important mechanism to amplify T cell-mediated diseases.
2024-02-09 | GSE253360 | GEO
Project description:Long-term dietary intake influences the structure and activity of the trillions of microorganisms residing in the human gut, but it remains unclear how rapidly and reproducibly the human gut microbiome responds to short-term macronutrient change. Here we show that the short-term consumption of diets composed entirely of animal or plant products alters microbial community structure and overwhelms inter-individual differences in microbial gene expression. The animal-based diet increased the abundance of bile-tolerant microorganisms (Alistipes, Bilophila and Bacteroides) and decreased the levels of Firmicutes that metabolize dietary plant polysaccharides (Roseburia, Eubacterium rectale and Ruminococcus bromii). Microbial activity mirrored differences between herbivorous and carnivorous mammals, reflecting trade-offs between carbohydrate and protein fermentation. Foodborne microbes from both diets transiently colonized the gut, including bacteria, fungi and even viruses. Finally, increases in the abundance and activity of Bilophila wadsworthia on the animal-based diet support a link between dietary fat, bile acids and the outgrowth of microorganisms capable of triggering inflammatory bowel disease. In concert, these results demonstrate that the gut microbiome can rapidly respond to altered diet, potentially facilitating the diversity of human dietary lifestyles. RNA-Seq analysis of the human gut microbiome during consumption of a plant- or animal-based diet.
2013-12-05 | E-GEOD-46761 | biostudies-arrayexpress
Project description:Roux-en-Y gastric bypass (RYGB) is highly effective in reversing obesity and associated diabetes. Recent observations in humans suggest a contributing role of increased circulating bile acids in mediating such effects. Here we use a diet-induced obesity mouse model and compared metabolic remission when bile flow was diverted through a gallbladder anastomosis to jejunum, ileum or duodenum (sham control). We found that only bile diversion to the ileum results in physiologic changes similar to RYGB including sustained improvements in weight, glucose tolerance and hepatic steatosis despite differential effects on hepatic gene expression. Circulating free fatty acids and triglycerides decrease while bile acids increase, particularly conjugated tauro-b-muricholic acid, an FXR antagonist. Activity of the hepatic FXR/FGF15 axis was reduced and associated with altered gut microbiota. Thus bile diversion, independent of surgical rearrangement of the gastrointestinal tract, imparts significant weight loss accompanied by improved glucose and lipid homeostasis that are hallmarks of RYGB. Total RNA from n = 5 DIO, n = 4 GB-IL, n = 5 RYGB mice livers was extracted of total RNA and submitted fro RNAseq
2015-05-13 | E-GEOD-68812 | biostudies-arrayexpress
Project description:Pancreatic cancer is the 3rd most prevalent cause of cancer related deaths in United states alone, with over 55000 patients being diagnosed in 2019 alone and nearly as many succumbing to it. Late detection, lack of effective therapy and poor understanding of pancreatic cancer systemically contributes to its poor survival statistics. Obesity and high caloric intake linked co-morbidities like type 2 diabetes (T2D) have been attributed as being risk factors for a number of cancers including pancreatic cancer. Studies on gut microbiome has shown that lifestyle factors as well as diet has a huge effect on the microbial flora of the gut. Further, modulation of gut microbiome has been seen to contribute to effects of intensive insulin therapy in mice on high fat diet. In another study, abnormal gut microbiota was reported to contribute to development of diabetes in Db/Db mice. Recent studies indicate that microbiome and microbial dysbiosis plays a role in not only the onset of disease but also in its outcome. In colorectal cancer, Fusobacterium has been reported to promote therapy resistance. Certain intra-tumoral bacteria have also been shown to elicit chemo-resistance by metabolizing anti-cancerous agents. In pancreatic cancer, studies on altered gut microbiome have been relatively recent. Microbial dysbiosis has been observed to be associated with pancreatic tumor progression. Modulation of microbiome has been shown to affect response to anti-PD1 therapy in this disease as well. However, most of the studies in pancreatic cancer and microbiome have remained focused om immune modulation. In the current study, we observed that in a T2D mouse model, the microbiome changed significantly as the hyperglycemia developed in these animals. Our results further showed that, tumors implanted in the T2D mice responded poorly to Gemcitabine/Paclitaxel (Gem/Pac) standard of care compared to those in the control group. A metabolomic reconstruction of the WGS of the gut microbiota further revealed that an enrichment of bacterial population involved in drug metabolism in the T2D group.
2020-11-30 | E-MTAB-8739 | biostudies-arrayexpress
Project description:TGR5 (Gpbar1) is a G protein-coupled receptor responsive to bile acids (BAs), which is expressed in different non-parenchymal cells of the liver, including biliary epithelial cells, liver-resident macrophages, sinusoidal endothelial cells (LSECs) and activated hepatic stellate cells (HSCs). Mice with targeted deletion of TGR5 are more susceptible towards cholestatic liver injury induced by cholic acid-feeding and bile duct ligation, resulting in a reduced proliferative response and increased liver injury. Conjugated lithocholic acid (LCA) represents the most potent TGR5 BA ligand and LCA-feeding has been used as a model to rapidly induce severe cholestatic liver injury in mice. Thus, TGR5 knockout (KO) mice and wildtype littermates were fed a diet supplemented with 1%LCA for 84 hours. Liver injury and gene expression changes induced by the LCA-diet revealed an enrichment of pathways associated with inflammation, proliferation and matrix remodelling. Knockout of TGR5 in mice caused upregulation of endothelin-1 (ET-1) expression in the livers. Analysis of TGR5-dependent ET-1 signalling in isolated LSECs and HSCs demonstrated that TGR5 activation reduces ET-1 expression and secretion from LSECs and triggers internalization of the ET-1 receptor in HSCs dampening ET-1 responsiveness. Thus, we identified two independent mechanisms by which TGR5 inhibits ET-1 signalling and modulates portal pressure.
2019-11-19 | GSE139075 | GEO
Project description:Bile acids are not only crucial for the uptake of lipids, but also have widespread systematic ef-fects and shape the gut-microbiome composition. Bile acids can directly shape the gut-microbiome and can be modified by bacteria such as Eggerthella lenta which in turn plays a crucial role in host metabolism and immune response. We cultivated eight strains that represent a simplified human intestinal microbiome and inves-tigated the molecular response to bile acids, co-culturing with Eggerthella lenta and the combina-tion. We observed growth inhibition of particularly gram-positive strains during bile acid stress, which could be alleviated through co-culturing with Eggerthella lenta. The inhibition of growth was related to a decrease in membrane integrity and genotoxic effects of bile acids, which we investigated using zeta potential measurements in combination with proteomic and metabolomic analyses. Co-culturing with Eggerthella lenta alleviated stress through formation of oxidized and epimer-ized bile acids and the molecular response to co-culturing was seen to be strain specific. We also note that we could detect the recently described Microbial Bile Salt Conjugates in our cultures. This study highlights the significance of a potent bile acid modifier and how in-depth molecular analyses are required to decipher cross-communication between gut and host.
2023-02-24 | PXD035496 | Pride
Project description:The gut microbiome can impact brain health and is altered in Parkinson’s disease (PD) patients. The vermiform appendix is a lymphoid tissue implicated in the storage and regulation of the gut microbiome. Here, we investigate changes in the functional microbiome in the appendix of PD patients relative to controls by metatranscriptomic analysis. In the PD appendix, we find microbial dysbiosis affecting lipid metabolism, particularly an upregulation of bacteria responsible for secondary bile acid synthesis. Likewise, proteomic and transcript analysis in the PD gut corroborates a disruption in cholesterol homeostasis and lipid catabolism. Bile acid analysis in the PD appendix reveals an increase in the microbially-derived, toxic secondary bile acids deoxycholic acid (DCA) and lithocholic acid (LCA). Synucleinopathy in mice induces similar microbiome alterations to those of PD patients and heightens microbial changes to gut inflammation. As observed in PD, the mouse model of synucleinopathy has elevated DCA and LCA. Raised levels of DCA and LCA can lead to liver injury, and an analysis of blood markers of liver dysfunction shows evidence of biliary abnormalities in PD patients, including elevated alkaline phosphatase and bilirubin. Increased bilirubin levels are also evident before PD diagnosis, in individuals at-risk of developing PD. In sum, microbially-derived toxic bile acids are heightened in PD and biliary changes may even precede the onset of overt motor symptoms.
2021-08-01 | GSE156647 | GEO