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:Cholestasis is caused by autoimmune reactions, drug-induced hepatotoxicity, viral infections of the liver and the obstruction of bile ducts by tumours or gallstones. Cholestatic conditions are associated with impaired innate and adaptive immunity, including alterations of the cellular functions of monocytes, macrophages, NK cells and T-cells. Bile acids act as signalling molecules, affecting lipopolysaccharide (LPS)-induced cytokine expression in primary human macrophages. The present manuscript investigates the impact of bile acids, such as taurolithocholic acid (TLC), on the transcriptome of human macrophages in the presence or absence of LPS. While TLC itself has almost no effect on gene expression under control conditions, this compound modulates the expression of 202 out of 865 transcripts in the presence of LPS. Interestingly, pathway analysis revealed that TLC specifically supressed the expression of genes involved in mediating pro-inflammatory effects, phagocytosis, interactions with pathogens and autophagy as well as the recruitment of immune cells, such as NK cells, neutrophils and T cells. These data indicate a broad influence of bile acids on inflammatory responses and immune functions in macrophages. These findings may contribute to the clinical observation that patients with cholestasis present a lack of response to bacterial or viral infections.
Project description:The major aetiological risk factor for Barrett's oesophagus and oesophageal adenocarcinoma is gastroesophageal reflux. This study's aim was to identify genes involved in the celular response to reflux in vitro. The Barrettâ??s oesophagus cell line, CP-A hTERT, was exposed to media with acid, deoxycholic acid or a primary bile salt mixture. RNA expression was compared with controls on Affymetrix U133 Plus 2.0 arrays. In CP-A hTERT, the greatest number of changes in gene expression was observed after treatment with deoxycholic acid, pH 4.5; 152 genes were up-regulated at 2 hours (91 at 6 hours) and 10 down-regulated at 2 hours (34 at 6 hours). 12 genes were identified and were subsequently assessed in patients with non-erosive reflux disease, oesophagitis, Barrett's oesophagus and oesophageal adenocarcinoma; Background and Aims: The major etiological risk factor for Barrettâ??s esophagus and esophageal adenocarcinoma is gastro-esophageal reflux. This studyâ??s aim was to identify genes involved in the cellular response to components of reflux both in vitro and in patients with reflux-related disease. Methods: The Barrettâ??s cell line, CP-A hTERT, was exposed to media with acid, deoxycholic acid or a primary bile salt mixture. RNA expression was compared with controls on Affymetrix U133 Plus 2.0 arrays. 12 genes of interest were analysed by Real Time PCR both in cell line and biopsies from 110 patients with non-erosive reflux disease, esophagitis, Barrettâ??s esophagus and esophageal adenocarcinoma. Results: In CP-A hTERT, the greatest number of changes in gene expression was observed after treatment with deoxycholic acid, pH 4.5. Of 12 genes analysed in biopsies, 10 were significantly different between the 4 groups with the largest change for anterior gradient homolog 2, which may modulate p53 function. This had highest expression in biopsies from Barrettâ??s esophagus (median gene fold change for Barrettâ??s esophagus versus non-erosive reflux disease, 411.2 (95% CI 290.5-682.7; p<0.01); esophageal adenocarcinoma versus non-erosive reflux disease 68.1 (20.5-161.4; p<0.01)). In addition 4 genes associated with development/differentiation were upregulated in Barrettâ??s biopsies compared to those from non-erosive reflux disease (SEL1L, MFNG, CRIP1 and EFNA1). Conclusions: Novel genes have been identified, whose expression is altered after acid and bile exposure in vitro and in biopsies from patients with reflux related diseases. These genes may have utility as biomarkers of response to reflux and should be assessed in prospective studies. Experiment Overall Design: The Barrett's oesophagus cell line CP-A hTERT was treated with a 15 minute exposure of acid (pH 4.5), a mixture of primary bile acids (pH 4.5) or deoxycholic acid (pH 4.5). RNA extraction occurred in treatment and non-treated cells at 2 hours and 6 hours. The treatments were performed in duplicate on 2 different days. RNA was compared in each treatment to each control at the relevant time points, in a 2 x 2 manner by using Affymetrex U133 Plus 2.0 arrays. Results of 12 genes were confirmed by Real Time PCR and were subsequently assessed in patients with non-erosive reflux disease, oesophagitis, Barrett's oesophagus and oesophageal adenocarcinoma.
Project description:This SuperSeries is composed of the SubSeries listed below. CD4+ T cells are tightly regulated by microbiota in the intestine, but whether intestinal T cells interface with host-derived metabolites is less clear. Here, we show that CD4+ T effector (Teff) cells upregulated the xenobiotic transporter, Mdr1, in the ileum to maintain homeostasis in the presence of bile acids. Whereas wild-type Teff cells upregulated Mdr1 in the ileum, those lacking Mdr1 displayed mucosal dysfunction and induced Crohn?s disease-like ileitis following transfer into Rag1-/- hosts. Mdr1 mitigated oxidative stress and enforced homeostasis in Teff cells exposed to conjugated bile acids (CBAs), a class of liver-derived emulsifying agents that actively circulate through the ileal mucosa. Blocking ileal CBA reabsorption in transferred Rag1-/- mice restored Mdr1-deficient Teff cell homeostasis and attenuated ileitis. Further, a subset of ileal Crohn?s disease patients displayed MDR1 loss of function. Together, these results suggest that coordinated interaction between mucosal Teff cells and CBAs in the ileum regulate intestinal immune homeostasis.