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Ridlon JM, Daniel SL, Gaskins HR. The Hylemon-Björkhem pathway of bile acid 7-dehydroxylation: history, biochemistry, and microbiology. J Lipid Res 2023; 64:100392. [PMID: 37211250 PMCID: PMC10382948 DOI: 10.1016/j.jlr.2023.100392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/07/2023] [Accepted: 05/11/2023] [Indexed: 05/23/2023] Open
Abstract
Bile acids are detergents derived from cholesterol that function to solubilize dietary lipids, remove cholesterol from the body, and act as nutrient signaling molecules in numerous tissues with functions in the liver and gut being the best understood. Studies in the early 20th century established the structures of bile acids, and by mid-century, the application of gnotobiology to bile acids allowed differentiation of host-derived "primary" bile acids from "secondary" bile acids generated by host-associated microbiota. In 1960, radiolabeling studies in rodent models led to determination of the stereochemistry of the bile acid 7-dehydration reaction. A two-step mechanism was proposed, which we have termed the Samuelsson-Bergström model, to explain the formation of deoxycholic acid. Subsequent studies with humans, rodents, and cell extracts of Clostridium scindens VPI 12708 led to the realization that bile acid 7-dehydroxylation is a result of a multi-step, bifurcating pathway that we have named the Hylemon-Björkhem pathway. Due to the importance of hydrophobic secondary bile acids and the increasing measurement of microbial bai genes encoding the enzymes that produce them in stool metagenome studies, it is important to understand their origin.
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Affiliation(s)
- Jason M Ridlon
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA; Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA; Cancer Center at Illinois, University of Illinois Urbana-Champaign, Urbana, IL, USA; Center for Advanced Study, University of Illinois Urbana-Champaign, Urbana, IL, USA; Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA.
| | - Steven L Daniel
- Department of Biological Sciences, Eastern Illinois University, Charleston, IL, USA
| | - H Rex Gaskins
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA; Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA; Cancer Center at Illinois, University of Illinois Urbana-Champaign, Urbana, IL, USA; Department of Biomedical and Translational Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA; Department of Pathobiology, University of Illinois Urbana-Champaign, Urbana, IL, USA
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Lee JW, Cowley ES, Wolf PG, Doden HL, Murai T, Caicedo KYO, Ly LK, Sun F, Takei H, Nittono H, Daniel SL, Cann I, Gaskins HR, Anantharaman K, Alves JMP, Ridlon JM. Formation of secondary allo-bile acids by novel enzymes from gut Firmicutes. Gut Microbes 2022; 14:2132903. [PMID: 36343662 PMCID: PMC9645264 DOI: 10.1080/19490976.2022.2132903] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The gut microbiome of vertebrates is capable of numerous biotransformations of bile acids, which are responsible for intestinal lipid digestion and function as key nutrient-signaling molecules. The human liver produces bile acids from cholesterol predominantly in the A/B-cis orientation in which the sterol rings are "kinked", as well as small quantities of A/B-trans oriented "flat" stereoisomers known as "primary allo-bile acids". While the complex multi-step bile acid 7α-dehydroxylation pathway has been well-studied for conversion of "kinked" primary bile acids such as cholic acid (CA) and chenodeoxycholic acid (CDCA) to deoxycholic acid (DCA) and lithocholic acid (LCA), respectively, the enzymatic basis for the formation of "flat" stereoisomers allo-deoxycholic acid (allo-DCA) and allo-lithocholic acid (allo-LCA) by Firmicutes has remained unsolved for three decades. Here, we present a novel mechanism by which Firmicutes generate the "flat" bile acids allo-DCA and allo-LCA. The BaiA1 was shown to catalyze the final reduction from 3-oxo-allo-DCA to allo-DCA and 3-oxo-allo-LCA to allo-LCA. Phylogenetic and metagenomic analyses of human stool samples indicate that BaiP and BaiJ are encoded only in Firmicutes and differ from membrane-associated bile acid 5α-reductases recently reported in Bacteroidetes that indirectly generate allo-LCA from 3-oxo-Δ4-LCA. We further map the distribution of baiP and baiJ among Firmicutes in human metagenomes, demonstrating an increased abundance of the two genes in colorectal cancer (CRC) patients relative to healthy individuals.
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Affiliation(s)
- Jae Won Lee
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA,Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Elise S. Cowley
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA,Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Patricia G. Wolf
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA,Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA,Institute for Health Research and Policy, University of Illinois Chicago, Chicago, IL, USA,University of Illinois Cancer Center, University of Illinois Chicago, Chicago, IL, USA
| | - Heidi L. Doden
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA,Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Tsuyoshi Murai
- School of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Hokkaido, Japan
| | | | - Lindsey K. Ly
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA,Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Furong Sun
- Mass Spectrometry Laboratory, School of Chemical Sciences, University of Illinois Urbana-Champaign, IL, USA
| | - Hajime Takei
- Junshin Clinic Bile Acid Institute, Tokyo, Japan
| | | | - Steven L. Daniel
- Department of Biological Sciences, Eastern Illinois University, Charleston, IL, USA
| | - Isaac Cann
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA,Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA,Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA,Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - H. Rex Gaskins
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA,Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA,Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA,Cancer Center at Illinois, Urbana, IL, USA
| | | | - João M. P. Alves
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Jason M. Ridlon
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA,Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA,Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA,Cancer Center at Illinois, Urbana, IL, USA,Center for Advanced Study, University of Illinois Urbana-Champaign, Urbana, IL, USA,Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA,CONTACT Jason M. Ridlon Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA
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Kakiyama G, Pandak WM, Gillevet PM, Hylemon PB, Heuman DM, Daita K, Takei H, Muto A, Nittono H, Ridlon JM, White MB, Noble NA, Monteith P, Fuchs M, Thacker LR, Sikaroodi M, Bajaj JS. Modulation of the fecal bile acid profile by gut microbiota in cirrhosis. J Hepatol 2013; 58:949-55. [PMID: 23333527 DOI: 10.1016/j.jhep.2013.01.003] [Citation(s) in RCA: 549] [Impact Index Per Article: 49.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 11/01/2012] [Accepted: 01/03/2013] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS The 7α-dehydroxylation of primary bile acids (BAs), chenodeoxycholic (CDCA) and cholic acid (CA) into the secondary BAs, lithocholic (LCA) and deoxycholic acid (DCA), is a key function of the gut microbiota. We aimed at studying the linkage between fecal BAs and gut microbiota in cirrhosis since this could help understand cirrhosis progression. METHODS Fecal microbiota were analyzed by culture-independent multitagged-pyrosequencing, fecal BAs using HPLC and serum BAs using LC-MS in controls, early (Child A) and advanced cirrhotics (Child B/C). A subgroup of early cirrhotics underwent BA and microbiota analysis before/after eight weeks of rifaximin. RESULTS Cross-sectional: 47 cirrhotics (24 advanced) and 14 controls were included. In feces, advanced cirrhotics had the lowest total, secondary, secondary/primary BA ratios, and the highest primary BAs compared to early cirrhotics and controls. Secondary fecal BAs were detectable in all controls but in a significantly lower proportion of cirrhotics (p<0.002). Serum primary BAs were higher in advanced cirrhotics compared to the rest. Cirrhotics, compared to controls, had a higher Enterobacteriaceae (potentially pathogenic) but lower Lachonospiraceae, Ruminococcaceae and Blautia (7α-dehydroxylating bacteria) abundance. CDCA was positively correlated with Enterobacteriaceae (r=0.57, p<0.008) while Ruminococcaceae were positively correlated with DCA (r=0.4, p<0.05). A positive correlation between Ruminococcaceae and DCA/CA (r=0.82, p<0.012) and Blautia with LCA/CDCA (r=0.61, p<0.03) was also seen. Prospective study: post-rifaximin, six early cirrhotics had reduction in Veillonellaceae and in secondary/primary BA ratios. CONCLUSIONS Cirrhosis, especially advanced disease, is associated with a decreased conversion of primary to secondary fecal BAs, which is linked to abundance of key gut microbiome taxa.
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