Molecular Physiology of Bile Acid Signaling in Health, Disease and Aging

2020 ◽  
Author(s):  
Alessia Perino ◽  
Hadrien Demagny ◽  
Laura Alejandra Velazquez-Villegas ◽  
Kristina Schoonjans
Keyword(s):  
Bile Acid ◽  
Gut Microbiota ◽  
Bile Acids ◽  
Gut Microbiome ◽  
Signaling Molecules ◽  
Therapeutic Strategies ◽  
Fine Tuning ◽  
Physiological Effects ◽  
Adaptive Responses ◽  
Molecular Physiology

Over the last two decades, bile acids (BAs) have become established as important signaling molecules that enable fine-tuned inter-tissue communication from the liver, their site of production, over the intestine, where they are modified by the gut microbiota, to virtually any organ, where they exert their pleiotropic physiological effects. The chemical variety of BAs, to a large extent determined by the gut microbiome, also allows for a complex fine-tuning of adaptive responses in our body. This review provides an overview of the mechanisms by which BA receptors coordinate several aspects of physiology and highlights new therapeutic strategies for diseases underlying pathological BA signaling.

scholarly journals Metagenomic analysis of bile salt biotransformation in the human gut microbiome

2019 ◽  
Author(s):  
Promi Das ◽  
Simonas Marcišauskas ◽  
Boyang Ji ◽  
Jens Nielsen
Keyword(s):  
Bile Acid ◽  
Gut Microbiota ◽  
Bile Salt ◽  
Bile Acids ◽  
Gut Microbiome ◽  
Healthy Controls ◽  
Bile Acid Pool ◽  
Metabolomics Data ◽  
Acid Pool ◽  
Secondary Bile Acids

Abstract Background: In the biochemical milieu of human colon, bile acids act as signaling mediators between the host and its gut microbiota. Biotransformation of primary to secondary bile acids have been known to be involved in the immune regulation of human physiology. Several 16S amplicon-based studies with inflammatory bowel disease (IBD) subjects were found to have an association with the level of fecal bile acids. However, a detailed investigation of all the bile salt biotransformation genes in the gut microbiome of healthy and IBD subjects has not been performed. Results: Here, we report a comprehensive analysis of the bile salt biotransformation genes and their distribution at the phyla level. Based on the analysis of shotgun metagenomes, we found that the IBD subjects harbored a significantly lower abundance of these genes compared to the healthy controls. Majority of these genes originated from Firmicutes in comparison to other phyla. From metabolomics data, we found that the IBD subjects were measured with a significantly low level of secondary bile acids and high levels of primary bile acids compared to that of the healthy controls. Conclusions: Our bioinformatics-driven approach of identifying bile salt biotransformation genes predicts the bile salt biotransformation potential in the gut microbiota of IBD subjects. The functional level of dysbiosis likely contributes to the variation in the bile acid pool. This study sets the stage to envisage potential solutions to modulate the gut microbiome with the objective to restore the bile acid pool in the gut.

scholarly journals Metagenomic analysis of bile salt biotransformation in the human gut microbiome

2019 ◽  
Author(s):  
Promi Das ◽  
Simonas Marcišauskas ◽  
Boyang Ji ◽  
Jens Nielsen
Keyword(s):  
Bile Acid ◽  
Gut Microbiota ◽  
Bile Salt ◽  
Bile Acids ◽  
Gut Microbiome ◽  
Healthy Controls ◽  
Bile Acid Pool ◽  
Metabolomics Data ◽  
Acid Pool ◽  
Secondary Bile Acids

Abstract Background: In the biochemical milieu of human colon, bile acids act as signaling mediators between the host and its gut microbiota. Biotransformation of primary to secondary bile acids have been known to be involved in the immune regulation of human physiology. Several 16S amplicon-based studies with inflammatory bowel disease (IBD) subjects were found to have an association with the level of fecal bile acids. However, a detailed investigation of all the bile acid biotransformation genes involved in the secondary bile acid metabolism has not been performed. Results: Here, we report a comprehensive analysis of the bile acid biotransformation genes and their distribution at the phyla level. Based on the analysis of shotgun metagenomes, we found that the IBD subjects harbored a significantly lower abundance of these genes compared to the healthy controls. Majority of these genes originated from Firmicutes in comparison to other phyla. From metabolomics data, we found that the IBD subjects were measured with a significantly low level of secondary bile acids and high levels of primary bile acids compared to that of the healthy controls. Conclusions: Our bioinformatics-driven approach of identifying bile acid biotransformation genes predicts the bile salt biotransformation potential in the gut microbiota of IBD subjects. The functional level of dysbiosis likely contributes to the variation in the bile acid pool. This study sets the stage to envisage potential solutions to modulate the gut microbiome with the objective to restore the bile acid pool in the gut.

scholarly journals Metagenomic analysis of bile salt biotransformation in the human gut microbiome

2019 ◽  
Author(s):  
Promi Das ◽  
Simonas Marcišauskas ◽  
Boyang Ji ◽  
Jens Nielsen
Keyword(s):  
Bile Acid ◽  
Gut Microbiota ◽  
Bile Salt ◽  
Bile Acids ◽  
Gut Microbiome ◽  
Healthy Controls ◽  
Bile Acid Pool ◽  
Metabolomics Data ◽  
Acid Pool ◽  
Secondary Bile Acids

Abstract Background: In the biochemical milieu of human colon, bile acids act as signaling mediators between the host and its gut microbiota. Biotransformation of primary to secondary bile acids have been known to be involved in the immune regulation of human physiology. Several 16S amplicon-based studies with inflammatory bowel disease (IBD) subjects were found to have an association with the level of fecal bile acids. However, a detailed investigation of all the bile salt biotransformation genes in the gut microbiome of healthy and IBD subjects has not been performed. Results: Here, we report a comprehensive analysis of the bile salt biotransformation genes and their distribution at the phyla level. Based on the analysis of shotgun metagenomes, we found that the IBD subjects harbored a significantly lower abundance of these genes compared to the healthy controls. Majority of these genes originated from Firmicutes in comparison to other phyla. From metabolomics data, we found that the IBD subjects were measured with a significantly low level of secondary bile acids and high levels of primary bile acids compared to that of the healthy controls. Conclusions: Our bioinformatics-driven approach of identifying bile salt biotransformation genes predicts the bile salt biotransformation potential in the gut microbiota of IBD subjects. The functional level of dysbiosis likely contributes to the variation in the bile acid pool. This study sets the stage to envisage potential solutions to modulate the gut microbiome with the objective to restore the bile acid pool in the gut.

scholarly journals Disease-Associated Gut Microbiota Reduces the Profile of Secondary Bile Acids in Pediatric Nonalcoholic Fatty Liver Disease

2021 ◽  
Vol 11 ◽  
Author(s):  
Jiake Yu ◽  
Hu Zhang ◽  
Liya Chen ◽  
Yufei Ruan ◽  
Yiping Chen ◽  
...  
Keyword(s):  
Liver Disease ◽  
Bile Acid ◽  
Gut Microbiota ◽  
Fatty Liver ◽  
Nonalcoholic Fatty Liver Disease ◽  
Bile Acids ◽  
Fatty Liver Disease ◽  
Healthy Children ◽  
Nonalcoholic Fatty Liver ◽  
Secondary Bile Acids

Children with nonalcoholic fatty liver disease (NAFLD) display an altered gut microbiota compared with healthy children. However, little is known about the fecal bile acid profiles and their association with gut microbiota dysbiosis in pediatric NAFLD. A total of 68 children were enrolled in this study, including 32 NAFLD patients and 36 healthy children. Fecal samples were collected and analyzed by metagenomic sequencing to determine the changes in the gut microbiota of children with NAFLD, and an ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) system was used to quantify the concentrations of primary and secondary bile acids. The associations between the gut microbiota and concentrations of primary and secondary bile acids in the fecal samples were then analyzed. We found that children with NAFLD exhibited reduced levels of secondary bile acids and alterations in bile acid biotransforming-related bacteria in the feces. Notably, the decrease in Eubacterium and Ruminococcaceae bacteria, which express bile salt hydrolase and 7α-dehydroxylase, was significantly positively correlated with the level of fecal lithocholic acid (LCA). However, the level of fecal LCA was negatively associated with the abundance of the potential pathogen Escherichia coli that was enriched in children with NAFLD. Pediatric NAFLD is characterized by an altered profile of gut microbiota and fecal bile acids. This study demonstrates that the disease-associated gut microbiota is linked with decreased concentrations of secondary bile acids in the feces. The disease-associated gut microbiota likely inhibits the conversion of primary to secondary bile acids.

Abstract P473: Obstructive Sleep Apnea Results In Microbial Bile Acid Biotransformations To Promote Atherosclerosis

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Amulya Lingaraju ◽  
Stephany Flores Ramos ◽  
Emily Gentry ◽  
Orit Poulsen ◽  
Pieter C Dorrestein ◽  
...  
Keyword(s):  
Obstructive Sleep Apnea ◽  
Bile Acid ◽  
Sleep Apnea ◽  
Bile Acids ◽  
Gut Microbiome ◽  
Atherosclerotic Lesion ◽  
Farnesoid X Receptor ◽  
Lesion Formation ◽  
Aortic Lesion ◽  
Obstructive Sleep

Obstructive sleep apnea (OSA) is an independent exacerbator of cardiovascular disease (CVD). However, it is unclear how OSA or it’s characteristic components, intermittent hypoxia and hypercapnia (IHC), increase CVD risk. Our previous work has shown that IHC reproducibly changes the gut microbiome dynamics in murine models of atherosclerosis and that these changes could affect host cardiovascular physiology through bile acids and phosphocholines. In our initial targeted metabolomics approach, changes in particular bile acids, such as taurocholic acid, taurodeoxycholic acid, and muricholic acid, were associated with and were predictive of IHC exposure in atherosclerotic Ldlr-/- mice. In a more recent study, we identified the formation of novel, microbially-synthesized conjugated bile acids by the gut microbiome that are more potent farnesoid X receptor agonists than other previously described bile acids, and thus, potentially can affect atherosclerosis formation. To determine whether these novel bile acids are associated with IHC-induced atherosclerosis, we characterized luminal bile acid changes in Ldlr-/- mice in an OSA model. We hypothesize that IHC alters the amount of microbially-synthesized novel bile acids and that these bile acids are associated with IHC-induced atherosclerosis. To test this hypothesis, we subjected atherogenic diet-fed Ldlr-/- mice to either room-air (control) or IHC conditions (n=10/condition) and assessed atherosclerotic lesion formation after 12 weeks post-diet. Mice under IHC conditions had significantly higher aortic lesion formation compared to controls. Assessment of fecal bile acid metabolites indicated changes in novel bile acid levels under IHC conditions. Moreover, correlational analysis showed that these novel bile acid changes were positively correlated with atherosclerotic lesion amounts, mainly driven by IHC conditions. Our results demonstrate that bile acid changes through microbial biotransformations occur under IHC conditions and could be the mechanistic link between OSA-induced microbiome changes and atherosclerosis.

scholarly journals Role of Bile Acids in Dysbiosis and Treatment of Nonalcoholic Fatty Liver Disease

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Caihua Wang ◽  
Chunpeng Zhu ◽  
Liming Shao ◽  
Jun Ye ◽  
Yimin Shen ◽  
...  
Keyword(s):  
Liver Disease ◽  
Bile Acid ◽  
Gut Microbiota ◽  
Fatty Liver ◽  
Nonalcoholic Fatty Liver Disease ◽  
Bile Acids ◽  
Fatty Liver Disease ◽  
Nonalcoholic Fatty Liver ◽  
Bile Acid Receptors

Nonalcoholic fatty liver disease (NAFLD) is a major health threat around the world and is characterized by dysbiosis. Primary bile acids are synthesized in the liver and converted into secondary bile acids by gut microbiota. Recent studies support the role of bile acids in modulating dysbiosis and NAFLD, while the mechanisms are not well elucidated. Dysbiosis may alter the size and the composition of the bile acid pool, resulting in reduced signaling of bile acid receptors such as farnesoid X receptor (FXR) and Takeda G protein-coupled receptor 5 (TGR5). These receptors are essential in lipid and glucose metabolism, and impaired bile acid signaling may cause NAFLD. Bile acids also reciprocally regulate the gut microbiota directly via antibacterial activity and indirectly via FXR. Therefore, bile acid signaling is closely linked to dysbiosis and NAFLD. During the past decade, stimulation of bile acid receptors with their agonists has been extensively explored for the treatment of NAFLD in both animal models and clinical trials. Early evidence has suggested the potential of bile acid receptor agonists in NAFLD management, but their long-term safety and effectiveness need further clarification.

scholarly journals Pharmacological Activation of PXR and CAR Downregulates Distinct Bile Acid-Metabolizing Intestinal Bacteria and Alters Bile Acid Homeostasis

2018 ◽  
Vol 168 (1) ◽  
pp. 40-60 ◽  
Author(s):  
Joseph L Dempsey ◽  
Dongfang Wang ◽  
Gunseli Siginir ◽  
Qiang Fei ◽  
Daniel Raftery ◽  
...  
Keyword(s):  
Bile Acid ◽  
Gut Microbiota ◽  
Gut Microbiome ◽  
Corn Oil ◽  
Constitutive Androstane Receptor ◽  
Intestinal Bacteria ◽  
Pregnane X Receptor ◽  
Bile Salt Hydrolase ◽  
Dependent Manner ◽  
Germ Free

AbstractThe gut microbiome regulates important host metabolic pathways including xenobiotic metabolism and intermediary metabolism, such as the conversion of primary bile acids (BAs) into secondary BAs. The nuclear receptors pregnane X receptor (PXR) and constitutive androstane receptor (CAR) are well-known regulators for xenobiotic biotransformation in liver. However, little is known regarding the potential effects of PXR and CAR on the composition and function of the gut microbiome. To test our hypothesis that activation of PXR and CAR regulates gut microbiota and secondary BA synthesis, 9-week-old male conventional and germ-free mice were orally gavaged with corn oil, PXR agonist PCN (75 mg/kg), or CAR agonist TCPOBOP (3 mg/kg) once daily for 4 days. PCN and TCPOBOP decreased two taxa in the Bifidobacterium genus, which corresponded with decreased gene abundance of the BA-deconjugating enzyme bile salt hydrolase. In liver and small intestinal content of germ-free mice, there was a TCPOBOP-mediated increase in total, primary, and conjugated BAs corresponding with increased Cyp7a1 mRNA. Bifidobacterium, Dorea, Peptociccaceae, Anaeroplasma, and Ruminococcus positively correlated with T-UDCA in LIC, but negatively correlated with T-CDCA in serum. In conclusion, PXR and CAR activation downregulates BA-metabolizing bacteria in the intestine and modulates BA homeostasis in a gut microbiota-dependent manner.

Disease-Associated Changes in Bile Acid Profiles and Links to Altered Gut Microbiota

2017 ◽  
Vol 35 (3) ◽  
pp. 169-177 ◽  
Author(s):  
Susan A. Joyce ◽  
Cormac G.M. Gahan
Keyword(s):  
Bile Acid ◽  
Gut Microbiota ◽  
Bile Acids ◽  
Farnesoid X Receptor ◽  
Gastrointestinal Microbiota ◽  
Signalling Molecules ◽  
Disease States ◽  
Irritable Bowel ◽  
Bile Acid Profiles ◽  
Bile Acid Receptors

The gastrointestinal microbiota plays a central role in the host metabolism of bile acids through deconjugation and dehydroxylation reactions, which generate unconjugated free bile acids and secondary bile acids respectively. These microbially generated bile acids are particularly potent signalling molecules that interact with host bile acid receptors (including the farnesoid X receptor, vitamin D receptor and TGR5 receptor) to trigger cellular responses that play essential roles in host lipid metabolism, electrolyte transport and immune regulation. Perturbations of microbial populations in the gut can therefore profoundly alter bile acid profiles in the host to impact upon the digestive and signalling properties of bile acids in the human superorganism. A number of recent studies have clearly demonstrated the occurrence of microbial disturbances allied to alterations in host bile acid profiles that occur across a range of disease states. Intestinal diseases including irritable bowel syndrome, inflammatory bowel disease (IBD), short bowel syndrome and Clostridium difficile infection all exhibit concurrent alterations in the composition of the gut microbiota and changes to host bile acid profiles. Similarly, extraintestinal diseases and syndromes such as asthma and obesity may be linked to aberrant bile acid profiles in the host. Here, we focus upon recent studies that highlight the links between alterations to gut microbial communities and altered bile acid profiles across a range of diseases from asthma to IBD.

scholarly journals Adjunctive Probiotics Alleviates Asthmatic Symptoms via Modulating the Gut Microbiome and Serum Metabolome

2021 ◽  
Author(s):  
Ailing Liu ◽  
Teng Ma ◽  
Ning Xu ◽  
Hao Jin ◽  
Feiyan Zhao ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Gut Microbiome ◽  
Conventional Therapy ◽  
Potential Effect ◽  
Therapeutic Strategies ◽  
Disease Phenotype ◽  
Human Gut ◽  
Asthma Symptoms ◽  
Novel Therapeutic Strategies ◽  
Novel Therapeutic

The human gut microbiota has a potential effect on the pathogenesis of asthma and is closely related to the disease phenotype. Our trial has demonstrated that co-administering Probio-M8 synergized with conventional therapy to alleviate asthma symptoms. The findings of the present study provide new insights into the pathogenesis and treatment of asthma, mechanisms of novel therapeutic strategies, and application of probiotics-based therapy.

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