tauromuricholate and Body-Weight

The human gut microbiota impacts host metabolism and has been implicated in the pathophysiology of obesity and metabolic syndromes. However, defining the roles of specific microbial activities and metabolites on host phenotypes has proven challenging due to the complexity of the microbiome-host ecosystem. Here, we identify strains from the abundant gut bacterial phylum Bacteroidetes that display selective bile salt hydrolase (BSH) activity. Using isogenic strains of wild-type and BSH-deleted

Topics: Amidohydrolases; Animals; Bacteroides thetaiotaomicron; Body Weight; Circadian Rhythm; Gastrointestinal Tract; Gene Expression Profiling; Germ-Free Life; Host Microbial Interactions; Immunity; Intestines; Liver; Metabolism; Mice; Respiration; Taurocholic Acid

Increasing evidence supports the view that intestinal farnesoid X receptor (FXR) is involved in glucose tolerance and that FXR signaling can be profoundly impacted by the gut microbiota. Selective manipulation of the gut microbiota-FXR signaling axis was reported to significantly impact glucose intolerance, but the precise molecular mechanism remains largely unknown. Here, caffeic acid phenethyl ester (CAPE), an over-the-counter dietary supplement and an inhibitor of bacterial bile salt hydrolase, increased levels of intestinal tauro-β-muricholic acid, which selectively suppresses intestinal FXR signaling. Intestinal FXR inhibition decreased ceramide levels by suppressing expression of genes involved in ceramide synthesis specifically in the intestinal ileum epithelial cells. The lower serum ceramides mediated decreased hepatic mitochondrial acetyl-CoA levels and pyruvate carboxylase (PC) activities and attenuated hepatic gluconeogenesis, independent of body weight change and hepatic insulin signaling in vivo; this was reversed by treatment of mice with ceramides or the FXR agonist GW4064. Ceramides substantially attenuated mitochondrial citrate synthase activities primarily through the induction of endoplasmic reticulum stress, which triggers increased hepatic mitochondrial acetyl-CoA levels and PC activities. These results reveal a mechanism by which the dietary supplement CAPE and intestinal FXR regulates hepatic gluconeogenesis and suggest that inhibiting intestinal FXR is a strategy for treating hyperglycemia.

Topics: Acetyl Coenzyme A; Amidohydrolases; Animals; Body Weight; Caffeic Acids; Ceramides; Diet, High-Fat; Gastrointestinal Microbiome; Gluconeogenesis; Ileum; Insulin; Intestinal Mucosa; Intestines; Isoxazoles; Liver; Male; Mice; Mice, Inbred C57BL; Mitochondria, Liver; Phenylethyl Alcohol; Pyruvate Carboxylase; Receptors, Cytoplasmic and Nuclear; Signal Transduction; Taurocholic Acid