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Hall B, Levy S, Dufault-Thompson K, Arp G, Zhong A, Ndjite GM, Weiss A, Braccia D, Jenkins C, Grant MR, Abeysinghe S, Yang Y, Jermain MD, Wu CH, Ma B, Jiang X. BilR is a gut microbial enzyme that reduces bilirubin to urobilinogen. Nat Microbiol 2024; 9:173-184. [PMID: 38172624 PMCID: PMC10769871 DOI: 10.1038/s41564-023-01549-x] [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: 03/15/2023] [Accepted: 11/07/2023] [Indexed: 01/05/2024]
Abstract
Metabolism of haem by-products such as bilirubin by humans and their gut microbiota is essential to human health, as excess serum bilirubin can cause jaundice and even neurological damage. The bacterial enzymes that reduce bilirubin to urobilinogen, a key step in this pathway, have remained unidentified. Here we used biochemical analyses and comparative genomics to identify BilR as a gut-microbiota-derived bilirubin reductase that reduces bilirubin to urobilinogen. We delineated the BilR sequences from similar reductases through the identification of key residues critical for bilirubin reduction and found that BilR is predominantly encoded by Firmicutes species. Analysis of human gut metagenomes revealed that BilR is nearly ubiquitous in healthy adults, but prevalence is decreased in neonates and individuals with inflammatory bowel disease. This discovery sheds light on the role of the gut microbiome in bilirubin metabolism and highlights the significance of the gut-liver axis in maintaining bilirubin homeostasis.
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Affiliation(s)
- Brantley Hall
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, College Park, MD, USA.
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, College Park, MD, USA.
| | - Sophia Levy
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, College Park, MD, USA
| | | | - Gabriela Arp
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, College Park, MD, USA
| | - Aoshu Zhong
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Glory Minabou Ndjite
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, College Park, MD, USA
| | - Ashley Weiss
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, College Park, MD, USA
| | - Domenick Braccia
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, College Park, MD, USA
| | - Conor Jenkins
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, USA
| | - Maggie R Grant
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, College Park, MD, USA
| | - Stephenie Abeysinghe
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, College Park, MD, USA
| | - Yiyan Yang
- National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Madison D Jermain
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, College Park, MD, USA
| | - Chih Hao Wu
- Program of Computational Biology, Bioinformatics, and Genomics, University of Maryland, College Park, MD, USA
| | - Bing Ma
- Institute for Genome Sciences, Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Xiaofang Jiang
- National Library of Medicine, National Institutes of Health, Bethesda, MD, USA.
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