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E-GEOD-34730 - The Microbial Metabolite Deoxycholic Acid Modulates Cholesterol Metabolism in the Germ-Free Mouse
Released on 8 January 2015, last updated on 9 January 2015
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
transcription profiling by array
John R Walker <email@example.com>, Andrew T Anfora, Eric C Peters, Ganes Bhat, Sanjay Agarwalla, Scott A Lesley, Thomas Hollenbeck, Van Nguyen-Tran