Hepatic reduction of the secondary bile acid 7-oxolithocholic acid is mediated by 11β-hydroxysteroid dehydrogenase 1

The oxidized bile acid 7-oxoLCA (7-oxolithocholic acid), formed primarily by gut micro-organisms, is reduced in human liver to CDCA (chenodeoxycholic acid) and, to a lesser extent, UDCA (ursodeoxycholic acid). The enzyme(s) responsible remained unknown. Using human liver microsomes, we observed enhanced 7-oxoLCA reduction in the presence of detergent. The reaction was dependent on NADPH and stimulated by glucose 6-phosphate, suggesting localization of the enzyme in the ER (endoplasmic reticulum) and dependence on NADPH-generating H6PDH (hexose-6-phosphate dehydrogenase). Using recombinant human 11β-HSD1 (11β-hydroxysteroid dehydrogenase 1), we demonstrate efficient conversion of 7-oxoLCA into CDCA and, to a lesser extent, UDCA. Unlike the reversible metabolism of glucocorticoids, 11β-HSD1 mediated solely 7-oxo reduction of 7-oxoLCA and its taurine and glycine conjugates. Furthermore, we investigated the interference of bile acids with 11β-HSD1-dependent interconversion of glucocorticoids. 7-OxoLCA and its conjugates preferentially inhibited cortisone reduction, and CDCA and its conjugates inhibited cortisol oxidation. Three-dimensional modelling provided an explanation for the binding mode and selectivity of the bile acids studied. The results reveal that 11β-HSD1 is responsible for 7-oxoLCA reduction in humans, providing a further link between hepatic glucocorticoid activation and bile acid metabolism. These findings also suggest the need for animal and clinical studies to explore whether inhibition of 11β-HSD1 to reduce cortisol levels would also lead to an accumulation of 7-oxoLCA, thereby potentially affecting bile acid-mediated functions.

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Identification of unique bile acid-metabolizing bacteria from the microbiome of centenarians

10.21203/rs.3.rs-115113/v1 ◽

2020 ◽

Author(s):

Kenya Honda ◽

Yuko Sato ◽

Koji Atarashi ◽

Damian Plichta ◽

Yasumichi Arai ◽

...

Keyword(s):

Bile Acid ◽

Bile Acids ◽

Lithocholic Acid ◽

Multidrug Resistant ◽

Bile Acid Metabolism ◽

Critical Determinant ◽

Secondary Bile Acid ◽

Clostridioides Difficile ◽

Vancomycin Resistant ◽

Secondary Bile Acids

Abstract Centenarians, or individuals who have lived more than a century, represent the ultimate model of successful longevity associated with decreased susceptibility to ageing-associated illness and chronic inflammation. The gut microbiota is considered to be a critical determinant of human health and longevity. Here we show that centenarians (average 107 yo) have a distinct gut microbiome enriched in microbes capable of generating unique secondary bile acids, including iso-, 3-oxo-, and isoallo-lithocholic acid (LCA), as compared to elderly (85-89 yo) and young (21-55 yo) controls. Among these bile acids, the biosynthetic pathway for isoalloLCA had not been described previously. By screening 68 bacterial isolates from a centenarian’s faecal microbiota, we identified Parabacteroides merdae and Odoribacteraceae strains as effective producers of isoalloLCA. Furthermore, we generated and tested mutant strains of P. merdae to show that the enzymes 5α-reductase (5AR) and 3β-hydroxysteroid dehydrogenase (3βHSDH) were responsible for isoalloLCA production. This secondary bile acid derivative exerted the most potent antimicrobial effects among the tested bile acid compounds against gram-positive (but not gram-negative) multidrug-resistant pathogens, including Clostridioides difficile and vancomycin-resistant Enterococcus faecium. These findings suggest that specific bile acid metabolism may be involved in reducing the risk of pathobiont infection, thereby potentially contributing to longevity.

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The lithocholic acid 6β-hydroxylase cytochrome P-450, CYP 3A10, is an active catalyst of steroid-hormone 6β-hydroxylation

Biochemical Journal ◽

10.1042/bj2910429 ◽

1993 ◽

Vol 291 (2) ◽

pp. 429-433 ◽

Cited By ~ 22

Author(s):

T K H Chang ◽

J Teixeira ◽

G Gil ◽

D J Waxman

Keyword(s):

Bile Acid ◽

Bile Acids ◽

Steroid Hormones ◽

Lithocholic Acid ◽

Liver Microsomes ◽

Microsomal Protein ◽

Secondary Bile Acid ◽

Cos Cells ◽

Major Activity ◽

Cytochrome P 450

CYP 3A10 is a hamster liver cytochrome P-450 (P450) that encodes lithocholic acid 6 beta-hydroxylase, an enzyme that plays an important role in the detoxification of the cholestatic secondary bile acid lithocholate. Western-blot analysis revealed that the expression of CYP 3A10 protein is male-specific in hamster liver microsomes, a finding that is consistent with earlier analysis of CYP 3A10 mRNA. Since it has not been established whether the specificities of bile acid hydroxylase P450s, such as CYP 3A10, are restricted to their anionic bile acid substrates, we investigated the role of CYP 3A10 in the metabolism of a series of neutral steroid hormones using cDNA directed-expression in COS cells. The steroid hormones examined, testosterone, androstenedione and progesterone, were each metabolized by the expressed CYP 3A10, with 6 beta-hydroxylation corresponding to a major activity in all three instances. CYP 3A10-dependent steroid hydroxylation was increased substantially when the microsomes were prepared from COS cells co-transfected with NADPH:P450 reductase cDNA. In this case, the expressed P450 actively catalysed the 6 beta-hydroxylation of testosterone (288 +/- 23 pmol of product formed/min per mg of COS-cell microsomal protein), androstenedione (107 +/- 19 pmol/min per mg) and progesterone (150 +/- 7 pmol/min per mg). Other major CYP 3A10-mediated steroid hydroxylase activities included androstenedione 16 alpha-hydroxylation, progesterone 16 alpha- and 21-hydroxylation, and the formation of several unidentified products. CYP 3A10 exhibited similar Vmax. values for the 6 beta-hydroxylation of androstenedione and lithocholic acid (132 and 164 pmol/min per mg respectively), but metabolized the bile acid with a 3-fold lower Km (25 microM, as against 75 microM for androstenedione). Together, these studies establish that the substrate specificity of the bile acid hydroxylase CYP 3A10 is not restricted to bile acids, and further suggest that CYP 3A10 can play a physiologically important role in the metabolism of two classes of endogenous P450 substrates:steroid hormones and bile acids.

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Lactobacillus acidophilusdisrupts collaborative multispecies bile acid metabolism

10.1101/296020 ◽

2018 ◽

Author(s):

Sydney Dautel ◽

Nymul Khan ◽

Kristoffer R. Brandvold ◽

Colin J. Brislawn ◽

Janine Hutchison ◽

...

Keyword(s):

Bile Acid ◽

Bile Acids ◽

Gastric Bypass Surgery ◽

Probiotic Strain ◽

Microbial Interactions ◽

Basic Knowledge ◽

Bile Acid Metabolism ◽

Secondary Bile Acid ◽

Microbe Interactions ◽

Successful Weight Loss

ABSTRACTBile acids are metabolic links between hosts and their gut microbiomes, yet little is known about the roles they play in microbe-to-microbe interactions. Here we present a study designed to investigate the effect that a common probiotic,Lactobacillus acidophilus, has on microbial interactions that lead to formation of secondary bile acids. A model microbial consortium was built from three human gut isolates,Clostridium scindens, Collinsella aerofaciens,andBlautia obeum, and cultured under different bile acid and probiotic treatments. A multi-omics platform that included mass spectrometry-based metabolomics and activity-based proteomic probes was used to produce two major results. The first, was that an uncommon secondary bile acid – ursocholate – was produced by a multi-species chemical synthesis pathway. This result highlights a new microbe-to-microbe interaction mediated by bile acids. The second finding was that the probiotic strain,L. acidophilus,quenched the observed interactions and effectively halted consortial synthesis of ursocholate. Little is known about the role that ursocholate plays in human health and development. However, we did discover that a decrease in ursocholate abundance corresponded with successful weight loss in patients after gastric bypass surgery versus those who did not lose weight after surgery. Hence, this study uncovered basic knowledge that may aid future designs of custom probiotic therapies to combat obesity.

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Temporal Fluctuations of Gut Microbiota and Bile Acid Metabolism in Critically Ill Children

10.21203/rs.3.rs-647124/v1 ◽

2021 ◽

Author(s):

Iain Robert Louis Kean ◽

Josef Wagner ◽

Anisha Wijeyesekera ◽

Marcus de Goffau ◽

Sarah Thurston ◽

...

Keyword(s):

Bile Acid ◽

Critical Illness ◽

Gut Microbiota ◽

Bile Acids ◽

Critically Ill ◽

Critically Ill Children ◽

Bile Acid Metabolism ◽

Rrna Gene ◽

Secondary Bile Acid ◽

Secondary Bile Acids

Abstract Background: Critical illness frequently requires the use of broad-spectrum antimicrobials to treat life-threatening infection. The resulting impact on microbiome diversity is profound, influencing gastrointestinal fermentation endpoints, host immune response and metabolic activity including the conversion of primary bile acids to secondary bile acids. We previously observed reduced fermentation capacity in the gut microbiota of critically ill children upon hospital admission, but the functional recovery trajectory of the paediatric gut microbiome during critical illness has not been well defined. Here, we longitudinally studied the intestinal microbiome and faecal bile acid profile of critically ill children during hospitalisation in a paediatric intensive care unit (PICU). The composition of the microbiome was determined by sequencing of the 16s rRNA gene, and bile acids were measured from faecal water by liquid chromatography hyphenated to mass spectrometry. Results: In comparison to admission faecal samples, members of Clostridium cluster XIVa and Lachnospiraceae recovered during the late-acute phase (days 8-10) of hospitalisation. Patients with infections had a lower proportion of Lachnospiraceae in their gut microbiota than control microbiota and patients with admitting diagnoses. The proportion of Recovery Associated Bacteria (RAB) was observed to decline with the length of PICU admission. Additionally, the proportions of RAB were reduced in those with systemic infection, respiratory failure, and undergoing surgery. Notably, Clostridioides were positively associated with the secondary bile acid deoxycholic acid, which we hypothesised to driven by secondary bile acid induced sporulation; the ratio of primary to secondary bile acids demonstrated recovery during critical illness. Conclusion: The recovery of secondary bile acids occurs quickly after intervention for critical illness. Bile acid recovery may be induced by the Lachnospiraceae , the composition of which shifts during critical illness. Our data suggest that gut health and early gut microbiota recovery can be assessed by readily quantifiable faecal bile acid profiles.

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

Functional Foods in Health and Disease ◽

10.31989/ffhd.v7i11.384 ◽

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

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Aryl hydrocarbon receptor (AhR) activation by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) dose-dependently shifts the gut microbiome consistent with the progression of steatosis to steatohepatitis with fibrosis

10.1101/2021.11.02.466980 ◽

2021 ◽

Author(s):

Russell R Fling ◽

Tim Zacharewski

Keyword(s):

Bile Acid ◽

Bile Acids ◽

Acid Metabolism ◽

Lactobacillus Species ◽

Bile Acid Metabolism ◽

Bile Salt Hydrolase ◽

Metagenomic Sequencing ◽

Secondary Bile Acid ◽

Alcoholic Fatty Liver ◽

Dose Dependent

Gut dysbiosis with disrupted enterohepatic bile acid metabolism is commonly associated with non-alcoholic fatty liver disease (NAFLD) and recapitulated in a NAFLD-phenotype elicited by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in mice. TCDD induces hepatic fat accumulation and increases levels of secondary bile acids including taurolithocholic acid and deoxycholic acid, microbial modified bile acids involved in host bile acid regulation signaling pathways. To investigate the effects of TCDD on the gut microbiota, cecum contents of male C57BL/6 mice orally gavaged with sesame oil vehicle or 0.3, 3, or 30 µg/kg TCDD were examined using shotgun metagenomic sequencing. Taxonomic analysis identified dose-dependent increases in Lactobacillus species (i.e., Lactobacillus reuteri). Increased species were also associated with dose-dependent increases in bile salt hydrolase sequences, responsible for deconjugation reactions in secondary bile acid metabolism. Increased L. reuteri levels were further associated with mevalonate-dependent isopentenyl diphosphate (IPP) biosynthesis and menaquinone biosynthesis genes. Analysis of gut microbiomes from cirrhosis patients identified increased abundance of these pathways as identified in the mouse cecum metagenomic analysis. These results extend the association of lactobacilli with the AhR/intestinal axis in NAFLD progression and highlight the similarities between TCDD-elicited phenotypes in mice to human NAFLD.

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Pharmacological effects of secondary bile acid microparticles in diabetic murine model

Current Diabetes Reviews ◽

10.2174/1573399816666200626213735 ◽

2020 ◽

Vol 16 ◽

Author(s):

Armin Mooranian ◽

Nassim Zamani ◽

Bozica Kovacevic ◽

Corina Mihaela Ionescu ◽

Giuseppe Luna ◽

...

Keyword(s):

Bile Acid ◽

Blood Glucose ◽

Bile Acids ◽

Lithocholic Acid ◽

Diabetes Treatment ◽

Secondary Bile Acid ◽

Glucose Levels ◽

Anti Inflammatory ◽

Antidiabetic Effects

Aim: Examine bile acids effects in Type 2 diabetes. Background: In recent studies, the bile acid ursodeoxycholic acid (UDCA) has shown potent anti-inflammatory effects in obese patients while in type 2 diabetics (T2D) levels of the pro-inflammatory bile acid lithocholic acid were increased, and levels of the anti-inflammatory bile acid chenodeoxycholic acid were decreased, in plasma. Objective: Hence, this study aimed to examine applications of novel UDCA nanoparticles in diabetes. Methods: Diabetic balb/c adult mice were divided into three equal groups and gavaged daily with either empty microcapsules, free UDCA, or microencapsulated UDCA over two weeks. Their blood, tissues, urine, and faeces were collected for blood glucose, inflammation, and bile acid analyses. UDCA resulted in modulatory effects on bile acids profile without antidiabetic effects suggesting that bile acid modulation was not directly linked to diabetes treatment. Results: UDCA resulted in modulatory effects on bile acids profile without antidiabetic effects suggesting that bile acid modulation was not directly linked to diabetes treatment. Conclusion: Bile acids modulated the bile profile without affecting blood glucose levels.

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Manipulating the Microbiome: An Alternative Treatment for Bile Acid Diarrhoea

Microbiology Research ◽

10.3390/microbiolres12020023 ◽

2021 ◽

Vol 12 (2) ◽

pp. 335-353

Author(s):

Evette B. M. Hillman ◽

Sjoerd Rijpkema ◽

Danielle Carson ◽

Ramesh P. Arasaradnam ◽

Elizabeth M. H. Wellington ◽

...

Keyword(s):

Bile Acid ◽

Bile Acids ◽

Gastrointestinal Disease ◽

Acid Synthesis ◽

Bile Acid Synthesis ◽

Bile Acid Metabolism ◽

The United Kingdom ◽

The 1960S ◽

Irritable Bowel ◽

The Uk

Bile acid diarrhoea (BAD) is a widespread gastrointestinal disease that is often misdiagnosed as irritable bowel syndrome and is estimated to affect 1% of the United Kingdom (UK) population alone. BAD is associated with excessive bile acid synthesis secondary to a gastrointestinal or idiopathic disorder (also known as primary BAD). Current licensed treatment in the UK has undesirable effects and has been the same since BAD was first discovered in the 1960s. Bacteria are essential in transforming primary bile acids into secondary bile acids. The profile of an individual’s bile acid pool is central in bile acid homeostasis as bile acids regulate their own synthesis. Therefore, microbiome dysbiosis incurred through changes in diet, stress levels and the introduction of antibiotics may contribute to or be the cause of primary BAD. This literature review focuses on primary BAD, providing an overview of bile acid metabolism, the role of the human gut microbiome in BAD and the potential options for therapeutic intervention in primary BAD through manipulation of the microbiome.

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Liver Bile Acid Changes in Mouse Models of Alzheimer’s Disease

International Journal of Molecular Sciences ◽

10.3390/ijms22147451 ◽

2021 ◽

Vol 22 (14) ◽

pp. 7451

Author(s):

Harpreet Kaur ◽

Drew Seeger ◽

Svetlana Golovko ◽

Mikhail Golovko ◽

Colin Kelly Combs

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Bile Acid ◽

Bile Acids ◽

Cholesterol Metabolism ◽

Amyloid Β ◽

Acid Synthesis ◽

Bile Acid Synthesis ◽

Liver Cholesterol ◽

Bile Acid Metabolism

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by progressive cognitive impairment. It is hypothesized to develop due to the dysfunction of two major proteins, amyloid-β (Aβ) and microtubule-associated protein, tau. Evidence supports the involvement of cholesterol changes in both the generation and deposition of Aβ. This study was performed to better understand the role of liver cholesterol and bile acid metabolism in the pathophysiology of AD. We used male and female wild-type control (C57BL/6J) mice to compare to two well-characterized amyloidosis models of AD, APP/PS1, and AppNL-G-F. Both conjugated and unconjugated primary and secondary bile acids were quantified using UPLC-MS/MS from livers of control and AD mice. We also measured cholesterol and its metabolites and identified changes in levels of proteins associated with bile acid synthesis and signaling. We observed sex differences in liver cholesterol levels accompanied by differences in levels of synthesis intermediates and conjugated and unconjugated liver primary bile acids in both APP/PS1 and AppNL-G-F mice when compared to controls. Our data revealed fundamental deficiencies in cholesterol metabolism and bile acid synthesis in the livers of two different AD mouse lines. These findings strengthen the involvement of liver metabolism in the pathophysiology of AD.

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