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Wolf PG, Cowley ES, Breister A, Matatov S, Lucio L, Polak P, Ridlon JM, Gaskins HR, Anantharaman K. Diversity and distribution of sulfur metabolic genes in the human gut microbiome and their association with colorectal cancer. MICROBIOME 2022; 10:64. [PMID: 35440042 PMCID: PMC9016944 DOI: 10.1186/s40168-022-01242-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 02/01/2022] [Indexed: 05/05/2023]
Abstract
BACKGROUND Recent evidence implicates microbial sulfidogenesis as a potential trigger of colorectal cancer (CRC), highlighting the need for comprehensive knowledge of sulfur metabolism within the human gut. Microbial sulfidogenesis produces genotoxic hydrogen sulfide (H2S) in the human colon using inorganic (sulfate) and organic (taurine/cysteine/methionine) substrates; however, the majority of studies have focused on sulfate reduction using dissimilatory sulfite reductases (Dsr). RESULTS Here, we show that genes for microbial sulfur metabolism are more abundant and diverse than previously observed and are statistically associated with CRC. Using ~ 17,000 bacterial genomes from publicly available stool metagenomes, we studied the diversity of sulfur metabolic genes in 667 participants across different health statuses: healthy, adenoma, and carcinoma. Sulfidogenic genes were harbored by 142 bacterial genera and both organic and inorganic sulfidogenic genes were associated with carcinoma. Significantly, the anaerobic sulfite reductase (asr) genes were twice as abundant as dsr, demonstrating that Asr is likely a more important contributor to sulfate reduction in the human gut than Dsr. We identified twelve potential pathways for reductive taurine metabolism and discovered novel genera harboring these pathways. Finally, the prevalence of metabolic genes for organic sulfur indicates that these understudied substrates may be the most abundant source of microbially derived H2S. CONCLUSIONS Our findings significantly expand knowledge of microbial sulfur metabolism in the human gut. We show that genes for microbial sulfur metabolism in the human gut are more prevalent than previously known, irrespective of health status (i.e., in both healthy and diseased states). Our results significantly increase the diversity of pathways and bacteria that are associated with microbial sulfur metabolism in the human gut. Overall, our results have implications for understanding the role of the human gut microbiome and its potential contributions to the pathogenesis of CRC. Video abstract.
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Affiliation(s)
- Patricia G Wolf
- Institute for Health Research and Policy, University of Illinois at Chicago, Chicago, IL, USA
- University of Illinois Cancer Center, University of Illinois at Chicago, Chicago, 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
| | - Elise S Cowley
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Adam Breister
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Sarah Matatov
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Luke Lucio
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Paige Polak
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - 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
| | - 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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