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Mullowney MW, Fiebig A, Schnizlein MK, McMillin M, Rose AR, Koval J, Rubin D, Dalal S, Sogin ML, Chang EB, Sidebottom AM, Crosson S. Microbially catalyzed conjugation of GABA and tyramine to bile acids. J Bacteriol 2024; 206:e0042623. [PMID: 38174933 PMCID: PMC10810215 DOI: 10.1128/jb.00426-23] [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: 12/13/2023] [Accepted: 12/13/2023] [Indexed: 01/05/2024] Open
Abstract
Bile acids (BAs) are cholesterol-derived molecules that aid in digestion and nutrient absorption, regulate host metabolic processes, and influence physiology of the gut microbiota. Both the host and its microbiome contribute to enzymatic modifications that shape the chemical diversity of BAs in the gut. Several bacterial species have been reported to conjugate standard amino acids to BAs, but it was not known if bacteria conjugate BAs to other amine classes. Here, we show that Bacteroides fragilis strain P207, isolated from a bacterial bloom in the J-pouch of a patient with ulcerative colitis pouchitis, conjugates standard amino acids and the neuroactive amines γ-aminobutyric acid (GABA) and tyramine to deoxycholic acid. We extended this analysis to other human gut isolates and identified species that are competent to conjugate GABA and tyramine to primary and secondary BAs, and further identified diverse BA-GABA and BA-tyramine amides in human stool. A longitudinal metabolomic analysis of J-pouch contents of the patient from whom B. fragilis P207 was isolated revealed highly reduced levels of secondary bile acids and a shifting BA amide profile before, during, and after onset of pouchitis, including temporal changes in several BA-GABA amides. Treatment of pouchitis with ciprofloxacin was associated with a marked reduction of nearly all BA amides in the J-pouch. Our study expands the known repertoire of conjugated bile acids produced by bacteria to include BA conjugates to GABA and tyramine and demonstrates that these molecules are present in the human gut. IMPORTANCE BAs are modified in multiple ways by host enzymes and the microbiota to produce a chemically diverse set of molecules that assist in the digestive process and impact many physiological functions. This study reports the discovery of bacterial species that conjugate the neuroactive amines, GABA and tyramine, to primary and secondary BAs. We further present evidence that BA-GABA and BA-tyramine conjugates are present in the human gut, and document a shifting BA-GABA profile in a human pouchitis patient before, during, and after inflammation and antibiotic treatment. GABA and tyramine are common metabolic products of the gut microbiota and potent neuroactive molecules. GABA- and tyramine-conjugated BAs may influence receptor-mediated regulatory mechanisms of humans and their gut microbes, and absorption of these molecules and their entry into enterohepatic circulation may impact host physiology at distal tissue sites. This study defines new conjugated bile acids in the human gut.
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Affiliation(s)
| | - Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Matthew K. Schnizlein
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Mary McMillin
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Amber R. Rose
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Jason Koval
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - David Rubin
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Sushila Dalal
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | | | - Eugene B. Chang
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | | | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
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2
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Fiebig A, Schnizlein MK, Pena-Rivera S, Trigodet F, Dubey AA, Hennessy MK, Basu A, Pott S, Dalal S, Rubin D, Sogin ML, Eren AM, Chang EB, Crosson S. Bile acid fitness determinants of a Bacteroides fragilis isolate from a human pouchitis patient. mBio 2024; 15:e0283023. [PMID: 38063424 PMCID: PMC10790697 DOI: 10.1128/mbio.02830-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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: 10/23/2023] [Accepted: 10/26/2023] [Indexed: 12/19/2023] Open
Abstract
IMPORTANCE The Gram-negative bacterium Bacteroides fragilis is a common member of the human gut microbiota that colonizes multiple host niches and can influence human physiology through a variety of mechanisms. Identification of genes that enable B. fragilis to grow across a range of host environments has been impeded in part by the relatively limited genetic tractability of this species. We have developed a high-throughput genetic resource for a B. fragilis strain isolated from a UC pouchitis patient. Bile acids limit microbial growth and are altered in abundance in UC pouches, where B. fragilis often blooms. Using this resource, we uncovered pathways and processes that impact B. fragilis fitness in bile and that may contribute to population expansions during bouts of gut inflammation.
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Affiliation(s)
- Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Matthew K. Schnizlein
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Selymar Pena-Rivera
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Florian Trigodet
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
- Helmholtz Institute for Functional Marine Biodiversity, University of Oldenburg, Oldenburg, Germany
| | - Abhishek Anil Dubey
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Miette K. Hennessy
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Anindita Basu
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Sebastian Pott
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Sushila Dalal
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - David Rubin
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | | | - A. Murat Eren
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
- Helmholtz Institute for Functional Marine Biodiversity, University of Oldenburg, Oldenburg, Germany
| | - Eugene B. Chang
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
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3
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Mullowney MW, Fiebig A, Schnizlein MK, McMillin M, Rose AR, Koval J, Rubin D, Dalal S, Sogin ML, Chang EB, Sidebottom AM, Crosson S. Microbially-catalyzed conjugation of GABA and tyramine to bile acids. bioRxiv 2023:2023.09.25.559407. [PMID: 37808758 PMCID: PMC10557584 DOI: 10.1101/2023.09.25.559407] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Bile acids (BAs) are cholesterol-derived molecules that aid in digestion and nutrient absorption, regulate host metabolic processes, and influence physiology of the gut microbiota. Both the host and its microbiome contribute to enzymatic modifications that shape the chemical diversity of BAs in the gut. Several bacterial species have been reported to conjugate standard amino acids to BAs, but it was not known if bacteria conjugate BAs to other amine classes. Here, we show that Bacteroides fragilis strain P207, isolated from a bacterial bloom in the J-pouch of a patient with ulcerative colitis (UC) pouchitis, conjugates standard amino acids and the neuroactive amines γ-aminobutyric acid (GABA) and tyramine to deoxycholic acid. We extended this analysis to other human gut isolates and identified species that are competent to conjugate GABA and tyramine to primary and secondary BAs, and further identified diverse BA-GABA and BA-tyramine amides in human stool. A longitudinal metabolomic analysis of J-pouch contents of the patient from whom B. fragilis P207 was isolated revealed highly reduced levels of secondary bile acids and a shifting BA amide profile before, during, and after onset of pouchitis, including temporal changes in several BA-GABA amides. Treatment of pouchitis with ciprofloxacin was associated with a marked reduction of nearly all BA amides in the J-pouch. Our study expands the known repertoire of conjugated bile acids produced by bacteria to include BA conjugates to GABA and tyramine and demonstrates that these molecules are present in the human gut.
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Affiliation(s)
- Michael W Mullowney
- Duchossois Family Institute, University of Chicago, 900 E. 57th St, Chicago, IL, 60637, USA
| | - Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Matthew K Schnizlein
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Mary McMillin
- Duchossois Family Institute, University of Chicago, 900 E. 57th St, Chicago, IL, 60637, USA
| | - Amber R Rose
- Duchossois Family Institute, University of Chicago, 900 E. 57th St, Chicago, IL, 60637, USA
| | - Jason Koval
- Department of Medicine, University of Chicago, 900 E. 57th St, Chicago, IL, 60637, USA
| | - David Rubin
- Department of Medicine, University of Chicago, 900 E. 57th St, Chicago, IL, 60637, USA
| | - Sushila Dalal
- Department of Medicine, University of Chicago, 900 E. 57th St, Chicago, IL, 60637, USA
| | | | - Eugene B Chang
- Department of Medicine, University of Chicago, 900 E. 57th St, Chicago, IL, 60637, USA
| | - Ashley M Sidebottom
- Duchossois Family Institute, University of Chicago, 900 E. 57th St, Chicago, IL, 60637, USA
| | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
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4
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Fiebig A, Schnizlein MK, Pena-Rivera S, Trigodet F, Dubey AA, Hennessy M, Basu A, Pott S, Dalal S, Rubin D, Sogin ML, Murat Eren A, Chang EB, Crosson S. Bile acid fitness determinants of a Bacteroides fragilis isolate from a human pouchitis patient. bioRxiv 2023:2023.05.11.540287. [PMID: 37214927 PMCID: PMC10197588 DOI: 10.1101/2023.05.11.540287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Bacteroides fragilis comprises 1-5% of the gut microbiota in healthy humans but can expand to >50% of the population in ulcerative colitis (UC) patients experiencing inflammation. The mechanisms underlying such microbial blooms are poorly understood, but the gut of UC patients has physicochemical features that differ from healthy patients and likely impact microbial physiology. For example, levels of the secondary bile acid deoxycholate (DC) are highly reduced in the ileoanal J-pouch of UC colectomy patients. We isolated a B. fragilis strain from a UC patient with pouch inflammation (i.e. pouchitis) and developed it as a genetic model system to identify genes and pathways that are regulated by DC and that impact B. fragilis fitness in DC and crude bile. Treatment of B. fragilis with a physiologically relevant concentration of DC reduced cell growth and remodeled transcription of one-quarter of the genome. DC strongly induced expression of chaperones and select transcriptional regulators and efflux systems and downregulated protein synthesis genes. Using a barcoded collection of ≈50,000 unique insertional mutants, we further defined B. fragilis genes that contribute to fitness in media containing DC or crude bile. Genes impacting cell envelope functions including cardiolipin synthesis, cell surface glycosylation, and systems implicated in sodium-dependent bioenergetics were major bile acid fitness factors. As expected, there was limited overlap between transcriptionally regulated genes and genes that impacted fitness in bile when disrupted. Our study provides a genome-scale view of a B. fragilis bile response and genetic determinants of its fitness in DC and crude bile.
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Affiliation(s)
- Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Matthew K. Schnizlein
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Selymar Pena-Rivera
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Florian Trigodet
- Department of Medicine, University of Chicago, Chicago, IL, USA
- Helmholtz Institute for Functional Marine Biodiversity, University of Oldenburg, Oldenburg, Germany
| | - Abhishek Anil Dubey
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Miette Hennessy
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Anindita Basu
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Sebastian Pott
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Sushila Dalal
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - David Rubin
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | | | - A. Murat Eren
- Department of Medicine, University of Chicago, Chicago, IL, USA
- Helmholtz Institute for Functional Marine Biodiversity, University of Oldenburg, Oldenburg, Germany
| | - Eugene B. Chang
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
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Abstract
Clostridioides difficile (formerly Clostridium difficile) infection is a substantial health and economic burden worldwide. Great strides have been made over the past several years in characterizing the physiology of C. difficile infection, particularly regarding how gut microorganisms and their host work together to provide colonization resistance. As mammalian hosts and their indigenous gut microbiota have co-evolved, they have formed a complex yet stable relationship that prevents invading microorganisms from establishing themselves. In this Review, we discuss the latest advances in our understanding of C. difficile physiology that have contributed to its success as a pathogen, including its versatile survival factors and ability to adapt to unique niches. Using discoveries regarding microorganism-host and microorganism-microorganism interactions that constitute colonization resistance, we place C. difficile within the fiercely competitive gut environment. A comprehensive understanding of these relationships is required to continue the development of precision medicine-based treatments for C. difficile infection.
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Affiliation(s)
- Matthew K Schnizlein
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Vincent B Young
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA.
- Department of Internal Medicine/Division of Infectious Diseases, University of Michigan Medical School, Ann Arbor, MI, USA.
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6
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Ostrowski MP, La Rosa SL, Kunath BJ, Robertson A, Pereira G, Hagen LH, Varghese NJ, Qiu L, Yao T, Flint G, Li J, McDonald SP, Buttner D, Pudlo NA, Schnizlein MK, Young VB, Brumer H, Schmidt TM, Terrapon N, Lombard V, Henrissat B, Hamaker B, Eloe-Fadrosh EA, Tripathi A, Pope PB, Martens EC. Mechanistic insights into consumption of the food additive xanthan gum by the human gut microbiota. Nat Microbiol 2022; 7:556-569. [PMID: 35365790 DOI: 10.1038/s41564-022-01093-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 02/24/2022] [Indexed: 12/13/2022]
Abstract
Processed foods often include food additives such as xanthan gum, a complex polysaccharide with unique rheological properties, that has established widespread use as a stabilizer and thickening agent. Xanthan gum's chemical structure is distinct from those of host and dietary polysaccharides that are more commonly expected to transit the gastrointestinal tract, and little is known about its direct interaction with the gut microbiota, which plays a central role in digestion of other dietary fibre polysaccharides. Here we show that the ability to digest xanthan gum is common in human gut microbiomes from industrialized countries and appears contingent on a single uncultured bacterium in the family Ruminococcaceae. Our data reveal that this primary degrader cleaves the xanthan gum backbone before processing the released oligosaccharides using additional enzymes. Some individuals harbour Bacteroides intestinalis that is incapable of consuming polymeric xanthan gum but grows on oligosaccharide products generated by the Ruminococcaceae. Feeding xanthan gum to germfree mice colonized with a human microbiota containing the uncultured Ruminococcaceae supports the idea that the additive xanthan gum can drive expansion of the primary degrader Ruminococcaceae, along with exogenously introduced B. intestinalis. Our work demonstrates the existence of a potential xanthan gum food chain involving at least two members of different phyla of gut bacteria and provides an initial framework for understanding how widespread consumption of a recently introduced food additive influences human microbiomes.
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Affiliation(s)
- Matthew P Ostrowski
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Sabina Leanti La Rosa
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.,Faculty of Biosciences, Norwegian University of Life Sciences, Ås, Norway
| | - Benoit J Kunath
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Andrew Robertson
- Life Sciences Institute: Natural Products Discovery Core, University of Michigan, Ann Arbor, MI, USA
| | - Gabriel Pereira
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Live H Hagen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | | | - Ling Qiu
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Tianming Yao
- Department of Food Science and Whistler Center for Carbohydrate Research, Purdue University, West Lafayette, IN, USA
| | - Gabrielle Flint
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - James Li
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sean P McDonald
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Duna Buttner
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Nicholas A Pudlo
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Matthew K Schnizlein
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Vincent B Young
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA.,Department of Internal Medicine, Infectious Diseases Division, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Thomas M Schmidt
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Nicolas Terrapon
- Centre National de la Recherche Scientifique, Aix-Marseille Univ, Marseille, France.,Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Marseille, France
| | - Vincent Lombard
- Centre National de la Recherche Scientifique, Aix-Marseille Univ, Marseille, France.,Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Marseille, France
| | - Bernard Henrissat
- Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.,Technical University of Denmark, DTU Bioengineering, Lyngby, Denmark
| | - Bruce Hamaker
- Department of Food Science and Whistler Center for Carbohydrate Research, Purdue University, West Lafayette, IN, USA
| | | | - Ashootosh Tripathi
- Life Sciences Institute: Natural Products Discovery Core, University of Michigan, Ann Arbor, MI, USA
| | - Phillip B Pope
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway. .,Faculty of Biosciences, Norwegian University of Life Sciences, Ås, Norway.
| | - Eric C Martens
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA.
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7
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Schnizlein MK, Vendrov KC, Edwards SJ, Martens EC, Young VB. Dietary Xanthan Gum Alters Antibiotic Efficacy against the Murine Gut Microbiota and Attenuates Clostridioides difficile Colonization. mSphere 2020; 5:e00708-19. [PMID: 31915217 PMCID: PMC6952194 DOI: 10.1128/msphere.00708-19] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 12/06/2019] [Indexed: 01/16/2023] Open
Abstract
Dietary fiber provides a variety of microbiota-mediated benefits ranging from anti-inflammatory metabolites to pathogen colonization resistance. A healthy gut microbiota protects against Clostridioides difficile colonization. Manipulation of these microbes through diet may increase colonization resistance to improve clinical outcomes. The primary objective of this study was to identify how the dietary fiber xanthan gum affects the microbiota and C. difficile colonization. We added 5% xanthan gum to the diet of C57BL/6 mice and examined its effect on the microbiota through 16S rRNA gene amplicon sequencing and short-chain fatty acid analysis. Following either cefoperazone or an antibiotic cocktail administration, we challenged mice with C. difficile and measured colonization by monitoring the CFU. Xanthan gum administration is associated with increases in fiber-degrading taxa and short-chain fatty acid concentrations. However, by maintaining both the diversity and absolute abundance of the microbiota during antibiotic treatment, the protective effects of xanthan gum administration on the microbiota were more prominent than the enrichment of these fiber-degrading taxa. As a result, mice that were on the xanthan gum diet experienced limited to no C. difficile colonization. Xanthan gum administration alters mouse susceptibility to C. difficile colonization by maintaining the microbiota during antibiotic treatment. While antibiotic-xanthan gum interactions are not well understood, xanthan gum has previously been used to bind drugs and alter their pharmacokinetics. Thus, xanthan gum may alter the activity of the oral antibiotics used to make the microbiota susceptible. Future research should further characterize how this and other common dietary fibers interact with drugs.IMPORTANCE A healthy gut bacterial community benefits the host by breaking down dietary nutrients and protecting against pathogens. Clostridioides difficile capitalizes on the absence of this community to cause diarrhea and inflammation. Thus, a major clinical goal is to find ways to increase resistance to C. difficile colonization by either supplementing with bacteria that promote resistance or a diet to enrich for those already present in the gut. In this study, we describe an interaction between xanthan gum, a human dietary additive, and the microbiota resulting in an altered gut environment that is protective against C. difficile colonization.
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Affiliation(s)
- Matthew K Schnizlein
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Kimberly C Vendrov
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan, Ann Arbor, Michigan, USA
| | - Summer J Edwards
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan, Ann Arbor, Michigan, USA
| | - Eric C Martens
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Vincent B Young
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan, Ann Arbor, Michigan, USA
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8
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Das NK, Schwartz AJ, Barthel G, Inohara N, Liu Q, Sankar A, Hill DR, Ma X, Lamberg O, Schnizlein MK, Arqués JL, Spence JR, Nunez G, Patterson AD, Sun D, Young VB, Shah YM. Microbial Metabolite Signaling Is Required for Systemic Iron Homeostasis. Cell Metab 2020; 31:115-130.e6. [PMID: 31708445 PMCID: PMC6949377 DOI: 10.1016/j.cmet.2019.10.005] [Citation(s) in RCA: 142] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 09/23/2019] [Accepted: 10/14/2019] [Indexed: 12/16/2022]
Abstract
Iron is a central micronutrient needed by all living organisms. Competition for iron in the intestinal tract is essential for the maintenance of indigenous microbial populations and for host health. How symbiotic relationships between hosts and native microbes persist during times of iron limitation is unclear. Here, we demonstrate that indigenous bacteria possess an iron-dependent mechanism that inhibits host iron transport and storage. Using a high-throughput screen of microbial metabolites, we found that gut microbiota produce metabolites that suppress hypoxia-inducible factor 2α (HIF-2α) a master transcription factor of intestinal iron absorption and increase the iron-storage protein ferritin, resulting in decreased intestinal iron absorption by the host. We identified 1,3-diaminopropane (DAP) and reuterin as inhibitors of HIF-2α via inhibition of heterodimerization. DAP and reuterin effectively ameliorated systemic iron overload. This work provides evidence of intestine-microbiota metabolic crosstalk that is essential for systemic iron homeostasis.
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Affiliation(s)
- Nupur K Das
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Andrew J Schwartz
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gabrielle Barthel
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Naohiro Inohara
- Department of Pathology and Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI 48109, USA
| | - Qing Liu
- Department of Veterinary and Biomedical Sciences, the Pennsylvania State University, University Park, PA 16802, USA
| | - Amanda Sankar
- Department of Pediatrics, Division of Hematology-Oncology, University of Michigan, Ann Arbor, MI 48109, USA
| | - David R Hill
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xiaoya Ma
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Olivia Lamberg
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Matthew K Schnizlein
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Juan L Arqués
- Departamento Tecnología de Alimentos, INIA, Carretera de La Coruña Km 7, Madrid 28040, Spain
| | - Jason R Spence
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gabriel Nunez
- Department of Pathology and Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI 48109, USA
| | - Andrew D Patterson
- Department of Veterinary and Biomedical Sciences, the Pennsylvania State University, University Park, PA 16802, USA
| | - Duxin Sun
- College of Pharmacy, University of Michigan, Ann Arbor, MI 48109, USA
| | - Vincent B Young
- Department of Internal Medicine, Division of Infectious Disease, University of Michigan, Ann Arbor, MI 48109, USA; Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yatrik M Shah
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI 48109, USA.
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9
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Seekatz AM, Schnizlein MK, Koenigsknecht MJ, Baker JR, Hasler WL, Bleske BE, Young VB, Sun D. Spatial and Temporal Analysis of the Stomach and Small-Intestinal Microbiota in Fasted Healthy Humans. mSphere 2019; 4:e00126-19. [PMID: 30867328 PMCID: PMC6416366 DOI: 10.1128/msphere.00126-19] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 02/23/2019] [Indexed: 02/07/2023] Open
Abstract
Although the microbiota in the proximal gastrointestinal (GI) tract have been implicated in health and disease, much about these microbes remains understudied compared to those in the distal GI tract. This study characterized the microbiota across multiple proximal GI sites over time in healthy individuals. As part of a study of the pharmacokinetics of oral mesalamine administration, healthy, fasted volunteers (n = 8; 10 observation periods total) were orally intubated with a four-lumen catheter with multiple aspiration ports. Samples were taken from stomach, duodenal, and multiple jejunal sites, sampling hourly (≤7 h) to measure mesalamine (administered at t = 0), pH, and 16S rRNA gene-based composition. We observed a predominance of Firmicutes across proximal GI sites, with significant variation compared to stool. The microbiota was more similar within individuals over time than between subjects, with the fecal microbiota being unique from that of the small intestine. The stomach and duodenal microbiota displayed highest intraindividual variability compared to jejunal sites, which were more stable across time. We observed significant correlations in the duodenal microbial composition with changes in pH; linear mixed models identified positive correlations with multiple Streptococcus operational taxonomic units (OTUs) and negative correlations with multiple Prevotella and Pasteurellaceae OTUs. Few OTUs correlated with mesalamine concentration. The stomach and duodenal microbiota exhibited greater compositional dynamics than the jejunum. Short-term fluctuations in the duodenal microbiota were correlated with pH. Given the unique characteristics and dynamics of the proximal GI tract microbiota, it is important to consider these local environments in health and disease states.IMPORTANCE The gut microbiota are linked to a variety of gastrointestinal diseases, including inflammatory bowel disease. Despite this importance, microbiota dynamics in the upper gastrointestinal tract are understudied. Our article seeks to understand what factors impact microbiota dynamics in the healthy human upper gut. We found that the upper gastrointestinal tract contains consistently prevalent bacterial OTUs that dominate the overall community. Microbiota variability is highest in the stomach and duodenum and correlates with pH.
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Affiliation(s)
- Anna M Seekatz
- Department of Internal Medicine, Division of Infectious Disease, University of Michigan, Ann Arbor, Michigan, USA
| | - Matthew K Schnizlein
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Mark J Koenigsknecht
- Department of Internal Medicine, Division of Infectious Disease, University of Michigan, Ann Arbor, Michigan, USA
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA
| | - Jason R Baker
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, University of Michigan, Ann Arbor, Michigan, USA
| | - William L Hasler
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, University of Michigan, Ann Arbor, Michigan, USA
| | - Barry E Bleske
- Department of Pharmacy Practice and Administrative Sciences, University of New Mexico, Albuquerque, New Mexico, USA
| | - Vincent B Young
- Department of Internal Medicine, Division of Infectious Disease, University of Michigan, Ann Arbor, Michigan, USA
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Duxin Sun
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA
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10
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Langsjoen RM, Auguste AJ, Rossi SL, Roundy CM, Penate HN, Kastis M, Schnizlein MK, Le KC, Haller SL, Chen R, Watowich SJ, Weaver SC. Host oxidative folding pathways offer novel anti-chikungunya virus drug targets with broad spectrum potential. Antiviral Res 2017; 143:246-251. [PMID: 28461071 DOI: 10.1016/j.antiviral.2017.04.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 04/05/2017] [Indexed: 11/15/2022]
Abstract
Alphaviruses require conserved cysteine residues for proper folding and assembly of the E1 and E2 envelope glycoproteins, and likely depend on host protein disulfide isomerase-family enzymes (PDI) to aid in facilitating disulfide bond formation and isomerization in these proteins. Here, we show that in human HEK293 cells, commercially available inhibitors of PDI or modulators thereof (thioredoxin reductase, TRX-R; endoplasmic reticulum oxidoreductin-1, ERO-1) inhibit the replication of CHIKV chikungunya virus (CHIKV) in vitro in a dose-dependent manner. Further, the TRX-R inhibitor auranofin inhibited Venezuelan equine encephalitis virus and the flavivirus Zika virus replication in vitro, while PDI inhibitor 16F16 reduced replication but demonstrated notable toxicity. 16F16 significantly altered the viral genome: plaque-forming unit (PFU) ratio of CHIKV in vitro without affecting relative intracellular viral RNA quantities and inhibited CHIKV E1-induced cell-cell fusion, suggesting that PDI inhibitors alter progeny virion infectivity through altered envelope function. Auranofin also increased the extracellular genome:PFU ratio but decreased the amount of intracellular CHIKV RNA, suggesting an alternative mechanism of action. Finally, auranofin reduced footpad swelling and viremia in the C57BL/6 murine model of CHIKV infection. Our results suggest that targeting oxidative folding pathways represents a potential new anti-alphavirus therapeutic strategy.
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Affiliation(s)
- Rose M Langsjoen
- Institute for Translational Science, University of Texas Medical Branch, Galveston, TX, USA; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA
| | - Albert J Auguste
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA; Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
| | - Shannan L Rossi
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA; Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
| | - Christopher M Roundy
- Institute for Translational Science, University of Texas Medical Branch, Galveston, TX, USA; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA
| | - Heidy N Penate
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA
| | - Maria Kastis
- Center in Environmental Toxicology, University of Texas Medical Branch, Galveston, TX, USA
| | | | - Kevin C Le
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
| | - Sherry L Haller
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA; Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
| | - Rubing Chen
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA; Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
| | - Stanley J Watowich
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA; Center in Environmental Toxicology, University of Texas Medical Branch, Galveston, TX, USA
| | - Scott C Weaver
- Institute for Translational Science, University of Texas Medical Branch, Galveston, TX, USA; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA; Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA.
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