Project description:Metabolic products of the microbiota can alter hematopoiesis. However, the contribution and site of action of bile acids is poorly understood. Here we demonstrate that the secondary bile acids, deoxycholic acid (DCA), and lithocholic acid (LCA) increase bone marrow myelopoiesis. Treatment of bone marrow cells with DCA and LCA preferentially expanded immunophenotypic and functional (CFU-GM) granulocyte-monocyte progenitors (GMPs). DCA treatment of sorted hematopoietic stem/progenitor cells (HSPCs) increased CFU-GMs, indicating that direct exposure of HSPCs to DCA sufficed to expand GMPs. We determined that the vitamin D receptor (VDR) was required for the DCA-induced increase in CFU-GMs and GMPs. Finally, single-cell RNA sequencing revealed that DCA significantly upregulated genes associated with myeloid differentiation and proliferation in GMPs. The action of DCA on HSPCs to expand GMPs in a VDR-dependent manner suggests a mechanism for how microbiome-host interactions may directly impact bone marrow hematopoiesis and the severity of infectious and inflammatory disease.
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.
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.
Project description:Effect of bile acids (TCA LCA TUDCA DCA) on isolated bacteria
Ruminococcus bromii, Bacteroides fragilis, and Lactobacillus paracasei
Project description:<p>This study investigated the regulatory effects of three probiotics (P. pentosaceus, B. coagulans, and E. faecalis) on bile acid metabolism in common carp (Cyprinus carpio) fed a high-carbohydrate-high-fat (HCHF) diet for 56 days. A targeted metabolomics approach using UHPLC-QTRAP-MS/MS with scheduled multiple reaction monitoring (MRM) was employed to quantify 10 bile acid components in hepatopancreatic tissues, including free bile acids (CDCA, CA, DCA, LCA, alpha-MCA) and their taurine-conjugated forms (TCDCA, TCA, TDCA, TLCA, Talpha-MCA, Tbeta-MCA, Tomega-MCA). The analysis aimed to elucidate whether probiotic supplementation alleviates HCHF-induced glycolipid metabolic disorders through modulating bile acid profiles and FXR signaling pathway. Furthermore, molecular docking was performed to predict the binding affinities of these bile acids to common carp FXR protein, with CDCA showing the strongest binding energy of -6.859 kcal/mol. The results revealed that all three probiotics significantly increased the contents of FXR-activating free bile acids (CDCA, CA, DCA, LCA) while decreasing conjugated bile acid levels, thereby inhibiting gluconeogenesis and lipogenesis through the FXR-SHP-CYP7A1/CYP8B1 and FXR-SHP-HNF4 alpha/FOXO1 pathways.</p>
Project description:In this study, we aimed at the characterization of C. difficile’s stress response to the main four human bile acids. Although, a phenotypically description of growth differences upon challenge with different bile acids has been described (Lewis 2016, Thanissery 2017), there is no information on the adaptation of gene expression available. We employed a comprehensive proteomics approach to record stress signatures of the unconjugated bile acids CA, CDCA, DCA and LCA during long-term-stress conditions and could depict a general stress response concerning all four bile acids, but also specific responses to only a single or a few of the different bile acids. Our results are a starting point for the understanding of how the individual bile acids cocktail of a patient can decide on the outcome of a C. difficile infection
Project description:In this study, we aimed at the characterization of C. difficile’s stress response to the main four human bile acids. Although, a phenotypically description of growth differences upon challenge with different bile acids has been described (Lewis 2016, Thanissery 2017), there is no information on the adaptation of gene expression available. We employed a comprehensive proteomics approach to record stress signatures of the unconjugated bile acids CA, CDCA, DCA and LCA in shock experiments as well as during long-term-stress conditions and could depict a general stress response concerning all four bile acids, but also specific responses to only a single or a few of the different bile acids. Our results are a starting point for the understanding of how the individual bile acids cocktail of a patient can decide on the outcome of a C. difficile infection.
Project description:Mechanistic understanding of transient exposures that lead to adverse health outcomes will enhance our ability to recognize biological signatures of disease. Here, we measured the transcriptomic and epigenomic alterations due to exposure to the metabolic reprogramming agent, dichloroacetic acid (DCA). Previously, we showed that exposure to DCA increased liver cancer in B6C3F1 mice after continuous or early life exposures similarly over background level. Measures from these studies did not support direct cytotoxic, mitogenic, or genotoxic modes-of-action of tumorigenesis. Using archived formalin-fixed liver samples, we utilized modern methodologies to measure gene expression and DNA methylation levels to link to previously generated phenotypic measures. Gene expression was measured by targeted RNA sequencing (TempO-seq 1500+ toxicity panel: 2754 total genes) in liver samples collected from 10-, 32-, 57-, and 78-week old mice exposed to deionized water (controls), DCA continuously at 3.5g/L in drinking water (“Direct” group), or DCA at 3.5g/L for 10-, 32-, or 57-weeks followed by control water (“Stop” groups). Genome-scaled alterations in DNA methylation were measured by Reduced Representation Bisulfite Sequencing (RRBS) at 78-weeks. Transcriptomic changes were most robust with concurrent or adjacent timepoints after exposure stoppage. DNA methylation alterations followed a similar pattern, measuring 2720 and 567 differentially methylated regions (DMRs) in 78-week Direct and 10-week “Stop” DCA exposure groups, respectively. Gene pathway analysis indicated cellular effects linked to increased oxidative metabolism, a primary mechanism of action for DCA, closer to exposure windows especially early in life. Conversely, many gene signatures and pathways reversed patterns later in life and reflected more pro-tumorigenic patterns for both current and prior DCA exposures. DNA methylation patterns linked to early gene pathway perturbations, suggesting persistence in the epigenome and possible regulatory effects. In total, results suggested that liver metabolic reprogramming effects of DCA interact with normal age mechanisms to increase tumor burden with both continuous and prior DCA exposure in the B6C3F1 rodent model.
Project description:The involvment of bile acids such as deoxycholic acid (DCA) in gastro-esophageal reflux disease and subsequent Barrettâs metaplsia has been postulated. This study examines gene expression induced by exposure to DCA in esophageal cells and may be utilised in cross-comparisons with data derived from gene expression studies of Barrettâs esophagus and associated adenocarcinoma. SKGT4 cells were exposed to 300um DCA over 24 hours in duplicate experiments including matched timepoint controls. RNA samples were taken at 4, 8, 12 and 24 hours from DCA (DCA) exposed and resting (REST) timepoint controls.