scholarly journals Clostridium scindensATCC 35704: Integration of Nutritional Requirements, the Complete Genome Sequence, and Global Transcriptional Responses to Bile Acids

2019 ◽  
Vol 85 (7) ◽  
Author(s):  
Saravanan Devendran ◽  
Rachana Shrestha ◽  
João M. P. Alves ◽  
Patricia G. Wolf ◽  
Lindsey Ly ◽  
...  
Keyword(s):  
Bile Acid ◽  
Amino Acid ◽  
Bile Acids ◽  
Cholic Acid ◽  
Acid Metabolism ◽  
Deoxycholic Acid ◽  
Nutritional Requirements ◽  
Bile Acid Metabolism ◽  
Content Type ◽  
Secondary Bile Acids

ABSTRACTIn the human gut,Clostridium scindensATCC 35704 is a predominant bacterium and one of the major bile acid 7α-dehydroxylating anaerobes. While this organism is well-studied relative to bile acid metabolism, little is known about the basic nutrition and physiology ofC. scindensATCC 35704. To determine the amino acid and vitamin requirements ofC. scindens, the leave-one-out (one amino acid group or vitamin) technique was used to eliminate the nonessential amino acids and vitamins. With this approach, the amino acid tryptophan and three vitamins (riboflavin, pantothenate, and pyridoxal) were found to be required for the growth ofC. scindens. In the newly developed defined medium,C. scindensfermented glucose mainly to ethanol, acetate, formate, and H2.The genome ofC. scindensATCC 35704 was completed through PacBio sequencing. Pathway analysis of the genome sequence coupled with transcriptome sequencing (RNA-Seq) under defined culture conditions revealed consistency with the growth requirements and end products of glucose metabolism. Induction with bile acids revealed complex and differential responses to cholic acid and deoxycholic acid, including the expression of potentially novel bile acid-inducible genes involved in cholic acid metabolism. Responses to toxic deoxycholic acid included expression of genes predicted to be involved in DNA repair, oxidative stress, cell wall maintenance/metabolism, chaperone synthesis, and downregulation of one-third of the genome. These analyses provide valuable insight into the overall biology ofC. scindenswhich may be important in treatment of disease associated with increased colonic secondary bile acids.IMPORTANCEC. scindensis one of a few identified gut bacterial species capable of converting host cholic acid into disease-associated secondary bile acids such as deoxycholic acid. The current work represents an important advance in understanding the nutritional requirements and response to bile acids of the medically important human gut bacterium,C. scindensATCC 35704. A defined medium has been developed which will further the understanding of bile acid metabolism in the context of growth substrates, cofactors, and other metabolites in the vertebrate gut. Analysis of the complete genome supports the nutritional requirements reported here. Genome-wide transcriptomic analysis of gene expression in the presence of cholic acid and deoxycholic acid provides a unique insight into the complex response ofC. scindensATCC 35704 to primary and secondary bile acids. Also revealed are genes with the potential to function in bile acid transport and metabolism.

scholarly journals Metabolism of Oxo-Bile Acids and Characterization of Recombinant 12α-Hydroxysteroid Dehydrogenases from Bile Acid 7α-Dehydroxylating Human Gut Bacteria

2018 ◽  
Vol 84 (10) ◽  
Author(s):  
Heidi Doden ◽  
Lina A. Sallam ◽  
Saravanan Devendran ◽  
Lindsey Ly ◽  
Greta Doden ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Bile Acid ◽  
Bile Acids ◽  
Cholic Acid ◽  
Deoxycholic Acid ◽  
Gut Bacteria ◽  
Dietary Lipids ◽  
Human Gut ◽  
Content Type ◽  
Low Activity

ABSTRACTBile acids are important cholesterol-derived nutrient signaling hormones, synthesized in the liver, that act as detergents to solubilize dietary lipids. Bile acid 7α-dehydroxylating gut bacteria generate the toxic bile acids deoxycholic acid and lithocholic acid from host bile acids. The ability of these bacteria to remove the 7-hydroxyl group is partially dependent on 7α-hydroxysteroid dehydrogenase (HSDH) activity, which reduces 7-oxo-bile acids generated by other gut bacteria. 3α-HSDH has an important enzymatic activity in the bile acid 7α-dehydroxylation pathway. 12α-HSDH activity has been reported for the low-activity bile acid 7α-dehydroxylating bacteriumClostridium leptum; however, this activity has not been reported for high-activity bile acid 7α-dehydroxylating bacteria, such asClostridium scindens,Clostridium hylemonae, andClostridium hiranonis. Here, we demonstrate that these strains express bile acid 12α-HSDH. The recombinant enzymes were characterized from each species and shown to preferentially reduce 12-oxolithocholic acid to deoxycholic acid, with low activity against 12-oxochenodeoxycholic acid and reduced activity when bile acids were conjugated to taurine or glycine. Phylogenetic analysis suggests that 12α-HSDH is widespread amongFirmicutes,Actinobacteriain theCoriobacteriaceaefamily, and human gutArchaea.IMPORTANCE12α-HSDH activity has been established in the medically important bile acid 7α-dehydroxylating bacteriaC. scindens,C. hiranonis, andC. hylemonae. Experiments with recombinant 12α-HSDHs from these strains are consistent with culture-based experiments that show a robust preference for 12-oxolithocholic acid over 12-oxochenodeoxycholic acid. Phylogenetic analysis identified novel members of the gut microbiome encoding 12α-HSDH. Future reengineering of 12α-HSDH enzymes to preferentially oxidize cholic acid may provide a means to industrially produce the therapeutic bile acid ursodeoxycholic acid. In addition, a cholic acid-specific 12α-HSDH expressed in the gut may be useful for the reduction in deoxycholic acid concentration, a bile acid implicated in cancers of the gastrointestinal (GI) tract.

scholarly journals The influence of probiotics on individual fecal secondary bile acid levels: a two-case study of schizophrenic patients receiving an atypical antipsychotic drug

2017 ◽  
Vol 7 (11) ◽  
pp. 849
Author(s):  
Yosuke Saito ◽  
Hiroyuki Nishimiya ◽  
Yasue Kondo ◽  
Toyoaki Sagae
Keyword(s):  
Bile Acid ◽  
Bile Salt ◽  
Bile Acids ◽  
Acid Metabolism ◽  
Bile Acid Metabolism ◽  
Bile Salt Hydrolase ◽  
Atypical Antipsychotic Drug ◽  
Secondary Bile Acid ◽  
Secondary Bile Acids ◽  
Bsh Activity

Background: Probiotics is used as a promising approach in the prevention and treatment of hypercholesterolemia. Modification of bile acid metabolism through the deconjugation of bile salts by microbial bile salt hydrolase (BSH) is considered to be the core mechanism of the hypocholesterolemic effects of probiotics. Nevertheless, BSH activity is reported to be detrimental to the human host due to the generation of toxic secondary bile acids. Thus, the influence of probiotic intake on bile acid metabolism needs to be elucidated. We analyzed the bile acid levels and microbiota in human fecal samples after probiotic supplementation to assess the influence of probiotic intake on fecal bile acid levels. Two patients hospitalized for schizophrenia and dyslipidemia, receiving an atypical antipsychotic drug, were enrolled in this study (Subjects A and B). Both subjects received Lactobacillus rhamnosus GG (LGG) for 4 weeks, and no probiotics for the following 4 weeks. Fecal samples were collected at baseline and after 4 and 8 weeks.Results: Conjugated bile acids may be modified by indigenous intestinal bacteria into unconjugated bile acids and secondary bile acids through deconjugation reactions by BSH activity and the subsequent 7a-dehydroxylation pathway, respectively. In the fecal microbiota from Subject A, the relative abundance of Bifidobacterium increased after LGG supplementation (30%–49%). Most Bifidobacterium and Lactobacillus strains that colonize mammalian intestines may report BSH activity, and in general bifidobacteria reveals a higher BSH activity than lactobacilli. The fecal unconjugated bile acid and secondary bile acid levels in Subject A increased after the LGG supplementation (0.36–1.79 and 1.82–16.19 mmol/g respectively). Although the LGG supplementation appears to promote bile acid deconjugation, most of the unconjugated bile acids in Subject A appear to have been modified into secondary bile acids. Alternatively, in Subject B there were no significant changes throughout the study.Conclusion: We observed a significant increase in the fecal secondary bile acid levels after probiotic administration in one of our cases. Further studies are needed to elucidate the factors affecting 7a-dehydroxylation of bile acids to confirm the safety of using probiotics.Keywords: bile salt hydrolase; BSH; dihydroxylation; Bifidobacterium

scholarly journals Impaired absorption of cholesterol and bile acids in patients with an ileoanal anastomosis

Gut ◽  
1997 ◽  
Vol 41 (6) ◽  
pp. 771-777 ◽  
Author(s):  
K Hakala ◽  
M Vuoristo ◽  
P Luukkonen ◽  
H J Järvinen ◽  
T A Miettinen
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Acid Metabolism ◽  
Saturation Index ◽  
Low Density Lipoprotein ◽  
Ileoanal Anastomosis ◽  
Density Lipoprotein ◽  
Cholesterol Absorption ◽  
Bile Acid Metabolism ◽  
Secondary Bile Acids

Background—No data exist on cholesterol absorption in patients with an ileoanal anastomosis (IAA).Aims—To study cholesterol absorption and its effects on cholesterol and bile acid metabolism in patients with an IAA.Patients and methods—Cholesterol absorption, and serum, biliary, and faecal lipids were studied in 24 patients with an IAA and 20 controls.Results—Fractional cholesterol absorption was significantly lower in the patients (36% versus 47% in controls). Surprisingly, the calculated intestinal influx of endogenous cholesterol was reduced so that the absolute absorption of cholesterol was decreased; elimination of cholesterol as faecal neutral steroids remained normal. Thus, the slightly increased cholesterol synthesis was mainly due to increased faecal bile acid excretion, which, in turn, was associated with reduced absorption and biliary secretion of bile acids. Serum total and low density lipoprotein (LDL) cholesterol and LDL triglycerides were lower in the patients. Molar percentage and saturation index of biliary cholesterol were slightly higher in patients with an IAA. Proportions of secondary bile acids in bile and faeces were diminished, and faecal unidentified bile acids were higher in patients.Conclusions—Cholesterol absorption is significantly impaired in patients with an IAA, and is closely related to changes in serum and biliary lipids observed in these patients.

Abstract 49: The Transcriptional Repressor MafG Regulates Cholesterol Catabolism

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Thomas Q de Aguiar Vallim ◽  
Elizabeth J Tarling ◽  
Hannah Ahn ◽  
Lee R Hagey ◽  
Casey E Romanoski ◽  
...  
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Acid Metabolism ◽  
Metabolic Diseases ◽  
Cholesterol Metabolism ◽  
Transcriptional Repressor ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Bile Acid Metabolism ◽  
Biliary Bile Acid

Elevated circulating cholesterol levels is a major risk factor for cardiovascular diseases (CVD), and therefore understanding pathways that affect cholesterol metabolism are important for potential treatment of CVD. The major route for cholesterol excretion is through its catabolism to bile acids. Specific bile acids are also potent signaling molecules that modulate metabolic pathways affecting lipid, glucose and bile acid homeostasis. Bile acids are synthesized from cholesterol in the liver, and the key enzymes involved in bile acid synthesis ( Cyp7a1 , Cyp8b1 ) are regulated transcriptionally by the nuclear receptor FXR. We have identified an FXR-regulated pathway upstream of a transcriptional repressor that controls multiple bile acid metabolism genes. We identify MafG as an FXR target gene and show that hepatic MAFG overexpression represses genes of the bile acid synthetic pathway, and modifies the biliary bile acid composition. In contrast, MafG loss-of-function studies cause de-repression of the bile acid genes with concordant changes in biliary bile acid levels. Finally, we identify functional MafG response elements in bile acid metabolism genes using ChIP-Seq analysis. Our studies identify a molecular mechanism for the complex feedback regulation of bile acid synthesis controlled by FXR. The identification of this pathway will likely have important implications in metabolic diseases.

scholarly journals Identification of bile acids in the serum and urine in cholestasis. Evidence for 6α-hydroxylation of bile acids in man

1976 ◽  
Vol 154 (2) ◽  
pp. 507-516 ◽  
Author(s):  
J A. Summerfield ◽  
B H. Billing ◽  
C H. L. Shackleton
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Acid Metabolism ◽  
Gas Chromatography Mass Spectrometry ◽  
Acid Mixture ◽  
Bile Acid Metabolism ◽  
Hyodeoxycholic Acid ◽  
Normal Man ◽  
Hyocholic Acid ◽  
Sulphate Conjugate

In this qualitative study of the pattern of bile acid excretion in cholestasis, methods are described for the isolation of bile acids from large volumes of urine and plasma. The bile acids were subjected to a group separation and identified by combined gas chromatography-mass spectrometry. The techniques were developed to allow identification of the minor components of the bile acid mixture. Four bile acids that have not previously been described in human urine and plasma were detected, namely 3β, 7α-dihydroxy-5β-cholan-24-oic acid, 3α, 6α-dihydroxy-5β-cholan-24-oic acid (hyodeoxycholic acid), 3α, 6α, 7α-trihydroxy-5β-cholan-24-oic acid (hyocholic acid) and 3α, 7β, 12α-trihydroxy-5β-cholan-24-oic acid. In addition three C27 steroids were found; 26-hydroxycholesterol and a trihydroxy cholestane, probably 5 β-cholestane-3α, 7α, 26-triol were found in the sulphate fraction of plasma and urine. In the plasma sample, a sulphate conjugate of 24-hydroxycholesterol was found. The presence of these compounds probably reflects the existence of further pathways for bile acid metabolism. It is not yet known whether this is a consequence of the cholestasis or whether they are also present in normal man, at much lower concentrations.

Radioimmunoassay of conjugated cholic acid, chenodeoxycholic acid, and deoxycholic acid from human serum, with use of 125I-labeled ligands.

1979 ◽  
Vol 25 (2) ◽  
pp. 264-268 ◽  
Author(s):  
O Mäentausta ◽  
O Jänne
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Cholic Acid ◽  
Chenodeoxycholic Acid ◽  
Deoxycholic Acid ◽  
Serum Samples ◽  
Analytical Recovery ◽  
Hepatobiliary Diseases ◽  
Polyethylene Glycol Precipitation ◽  
Free Serum

Abstract We describe a method for radioimmunoassay of conjugated cholic acid, chenodeoxycholic acid, and deoxycholic acid in serum. In the method, 125I-labeled bile acid conjugates are used as the tracers along with antibodies raised against individual bile acid-bovine serum albumin conjugates. Antibody-bound and free bile acids were separated by polyethylene glycol precipitation (final concentration, 125 g/L). Before radioimmunoassay, 0.1-mL serum samples were precipitated with nine volumes of ethanol, and portions from the supernate were used in the assays. The lowest measurable amounts of the bile acids, expressed as pmol/tube, were: cholic acid conjugates, 2; chenodeoxycholic acid conjugates, 0.5; and deoxycholic acid conjugates. 2. Analytical recovery of bile acids added to bile acid-free serum ranged from 85 to 110%; intra-assay and inter-assay CVs ranged from 3.2 to 5.3% and from 5.3 to 12.2%, respectively. Concentrations (mean +/- SD) of the bile acid conjugates in serum from apparently healthy women and men (in mumol/L) were: cholic acid conjugates, 0.43 +/- 0.17 (n = 126); chenodeoxycholic acid conjugates, 0.47 +/- 0.23 (n = 111); and deoxycholic acid conjugates, 0.33 +/- 0.11 (n = 96). The values for primary bile acids were greatly increased in patients with various hepatobiliary diseases.

scholarly journals Ursodeoxycholic Acid and Its Taurine- or Glycine-Conjugated Species Reduce Colitogenic Dysbiosis and Equally Suppress Experimental Colitis in Mice

2017 ◽  
Vol 83 (7) ◽  
Author(s):  
Lien Van den Bossche ◽  
Pieter Hindryckx ◽  
Lindsey Devisscher ◽  
Sarah Devriese ◽  
Sophie Van Welden ◽  
...  
Keyword(s):  
Community Structure ◽  
Bile Acid ◽  
Bile Acids ◽  
Experimental Colitis ◽  
Acid Therapy ◽  
Content Type ◽  
Bile Acid Therapy ◽  
Inflammatory Bowel ◽  
The Impact ◽  
Secondary Bile Acids

ABSTRACT The promising results seen in studies of secondary bile acids in experimental colitis suggest that they may represent an attractive and safe class of drugs for the treatment of inflammatory bowel diseases (IBD). However, the exact mechanism by which bile acid therapy confers protection from colitogenesis is currently unknown. Since the gut microbiota plays a crucial role in the pathogenesis of IBD, and exogenous bile acid administration may affect the community structure of the microbiota, we examined the impact of the secondary bile acid ursodeoxycholic acid (UDCA) and its taurine or glycine conjugates on the fecal microbial community structure during experimental colitis. Daily oral administration of UDCA, tauroursodeoxycholic acid (TUDCA), or glycoursodeoxycholic acid (GUDCA) equally lowered the severity of dextran sodium sulfate-induced colitis in mice, as evidenced by reduced body weight loss, colonic shortening, and expression of inflammatory cytokines. Illumina sequencing demonstrated that bile acid therapy during colitis did not restore fecal bacterial richness and diversity. However, bile acid therapy normalized the colitis-associated increased ratio of Firmicutes to Bacteroidetes. Interestingly, administration of bile acids prevented the loss of Clostridium cluster XIVa and increased the abundance of Akkermansia muciniphila, bacterial species known to be particularly decreased in IBD patients. We conclude that UDCA, which is an FDA-approved drug for cholestatic liver disorders, could be an attractive treatment option to reduce dysbiosis and ameliorate inflammation in human IBD. IMPORTANCE Secondary bile acids are emerging as attractive candidates for the treatment of inflammatory bowel disease. Although bile acids may affect the intestinal microbial community structure, which significantly contributes to the course of these inflammatory disorders, the impact of bile acid therapy on the fecal microbiota during colitis has not yet been considered. Here, we studied the alterations in the fecal microbial abundance in colitic mice following the administration of secondary bile acids. Our results show that secondary bile acids reduce the severity of colitis and ameliorate colitis-associated fecal dysbiosis at the phylum level. This study indicates that secondary bile acids might act as a safe and effective drug for inflammatory bowel disease.

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