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Youngblom MA, Smith TM, Murray HJ, Pepperell CS. Adaptation of the Mycobacterium tuberculosis transcriptome to biofilm growth. PLoS Pathog 2024; 20:e1012124. [PMID: 38635841 PMCID: PMC11060545 DOI: 10.1371/journal.ppat.1012124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 04/30/2024] [Accepted: 03/14/2024] [Indexed: 04/20/2024] Open
Abstract
Mycobacterium tuberculosis (M. tb), the causative agent of tuberculosis (TB), is a leading global cause of death from infectious disease. Biofilms are increasingly recognized as a relevant growth form during M. tb infection and may impede treatment by enabling bacterial drug and immune tolerance. M. tb has a complicated regulatory network that has been well-characterized for many relevant disease states, including dormancy and hypoxia. However, despite its importance, our knowledge of the genes and pathways involved in biofilm formation is limited. Here we characterize the biofilm transcriptomes of fully virulent clinical isolates and find that the regulatory systems underlying biofilm growth vary widely between strains and are also distinct from regulatory programs associated with other environmental cues. We used experimental evolution to investigate changes to the transcriptome during adaptation to biofilm growth and found that the application of a uniform selection pressure resulted in loss of strain-to-strain variation in gene expression, resulting in a more uniform biofilm transcriptome. The adaptive trajectories of transcriptomes were shaped by the genetic background of the M. tb population leading to convergence on a sub-lineage specific transcriptome. We identified widespread upregulation of non-coding RNA (ncRNA) as a common feature of the biofilm transcriptome and hypothesize that ncRNA function in genome-wide modulation of gene expression, thereby facilitating rapid regulatory responses to new environments. These results reveal a new facet of the M. tb regulatory system and provide valuable insight into how M. tb adapts to new environments.
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Affiliation(s)
- Madison A. Youngblom
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Madison-Wisconsin, Madison, Wisconsin, United States of America
| | - Tracy M. Smith
- Department of Medicine (Infectious Diseases), School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Holly J. Murray
- Department of Medicine (Infectious Diseases), School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Caitlin S. Pepperell
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Madison-Wisconsin, Madison, Wisconsin, United States of America
- Department of Medicine (Infectious Diseases), School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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2
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McQuail J, Matera G, Gräfenhan T, Bischler T, Haberkant P, Stein F, Vogel J, Wigneshweraraj S. Global Hfq-mediated RNA interactome of nitrogen starved Escherichia coli uncovers a conserved post-transcriptional regulatory axis required for optimal growth recovery. Nucleic Acids Res 2024; 52:2323-2339. [PMID: 38142457 PMCID: PMC10954441 DOI: 10.1093/nar/gkad1211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/17/2023] [Accepted: 12/20/2023] [Indexed: 12/26/2023] Open
Abstract
The RNA binding protein Hfq has a central role in the post-transcription control of gene expression in many bacteria. Numerous studies have mapped the transcriptome-wide Hfq-mediated RNA-RNA interactions in growing bacteria or bacteria that have entered short-term growth-arrest. To what extent post-transcriptional regulation underpins gene expression in growth-arrested bacteria remains unknown. Here, we used nitrogen (N) starvation as a model to study the Hfq-mediated RNA interactome as Escherichia coli enter, experience, and exit long-term growth arrest. We observe that the Hfq-mediated RNA interactome undergoes extensive changes during N starvation, with the conserved SdsR sRNA making the most interactions with different mRNA targets exclusively in long-term N-starved E. coli. Taking a proteomics approach, we reveal that in growth-arrested cells SdsR influences gene expression far beyond its direct mRNA targets. We demonstrate that the absence of SdsR significantly compromises the ability of the mutant bacteria to recover growth competitively from the long-term N-starved state and uncover a conserved post-transcriptional regulatory axis which underpins this process.
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Affiliation(s)
- Josh McQuail
- Section of Molecular Microbiology and Centre for Bacterial Resistance Biology, Faculty of Medicine, Imperial College London, UK
| | - Gianluca Matera
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), D-97080 Würzburg, Germany
| | - Tom Gräfenhan
- Core Unit Systems Medicine, University of Würzburg, D-97080 Würzburg, Germany
| | - Thorsten Bischler
- Core Unit Systems Medicine, University of Würzburg, D-97080 Würzburg, Germany
| | - Per Haberkant
- Proteomics Core Facility, EMBL Heidelberg, D-69117,Heidelberg, Germany
| | - Frank Stein
- Proteomics Core Facility, EMBL Heidelberg, D-69117,Heidelberg, Germany
| | - Jörg Vogel
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), D-97080 Würzburg, Germany
- Institute for Molecular Infection Biology (IMIB), Faculty of Medicine, University of Würzburg, D-97080 Würzburg, Germany
| | - Sivaramesh Wigneshweraraj
- Section of Molecular Microbiology and Centre for Bacterial Resistance Biology, Faculty of Medicine, Imperial College London, UK
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3
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Pensinger DA, Dobrila HA, Stevenson DM, Hryckowian ND, Amador-Noguez D, Hryckowian AJ. Exogenous butyrate inhibits butyrogenic metabolism and alters virulence phenotypes in Clostridioides difficile. mBio 2024; 15:e0253523. [PMID: 38289141 PMCID: PMC10936429 DOI: 10.1128/mbio.02535-23] [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: 09/22/2023] [Accepted: 12/20/2023] [Indexed: 02/13/2024] Open
Abstract
The gut microbiome engenders colonization resistance against the diarrheal pathogen Clostridioides difficile, but the molecular basis of this colonization resistance is incompletely understood. A prominent class of gut microbiome-produced metabolites important for colonization resistance against C. difficile is short-chain fatty acids (SCFAs). In particular, one SCFA (butyrate) decreases the fitness of C. difficile in vitro and is correlated with C. difficile-inhospitable gut environments, both in mice and in humans. Here, we demonstrate that butyrate-dependent growth inhibition in C. difficile occurs under conditions where C. difficile also produces butyrate as a metabolic end product. Furthermore, we show that exogenous butyrate is internalized into C. difficile cells and is incorporated into intracellular CoA pools where it is metabolized in a reverse (energetically unfavorable) direction to crotonyl-CoA and (S)-3-hydroxybutyryl-CoA and/or 4-hydroxybutyryl-CoA. This internalization of butyrate and reverse metabolic flow of a butyrogenic pathway(s) in C. difficile coincides with alterations in toxin release and sporulation. Together, this work highlights butyrate as a marker of a C. difficile-inhospitable environment to which C. difficile responds by releasing its diarrheagenic toxins and producing environmentally resistant spores necessary for transmission between hosts. These findings provide foundational data for understanding the molecular and genetic basis of how C. difficile growth is inhibited by butyrate and how butyrate alters C. difficile virulence in the face of a highly competitive and dynamic gut environment.IMPORTANCEThe gut microbiome engenders colonization resistance against the diarrheal pathogen Clostridioides difficile, but the molecular basis of this colonization resistance is incompletely understood, which hinders the development of novel therapeutic interventions for C. difficile infection (CDI). We investigated how C. difficile responds to butyrate, an end-product of gut microbiome community metabolism which inhibits C. difficile growth. We show that exogenously produced butyrate is internalized into C. difficile, which inhibits C. difficile growth by interfering with its own butyrate production. This growth inhibition coincides with increased toxin release from C. difficile cells and the production of environmentally resistant spores necessary for transmission between hosts. Future work to disentangle the molecular mechanisms underlying these growth and virulence phenotypes will likely lead to new strategies to restrict C. difficile growth in the gut and minimize its pathogenesis during CDI.
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Affiliation(s)
- Daniel A. Pensinger
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
- Department of Medical Microbiology & Immunology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Horia A. Dobrila
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
- Department of Medical Microbiology & Immunology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - David M. Stevenson
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Nicole D. Hryckowian
- Department of Medical Microbiology & Immunology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Daniel Amador-Noguez
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Andrew J. Hryckowian
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
- Department of Medical Microbiology & Immunology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
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Ruhland E, Siemers M, Gerst R, Späth F, Vogt LN, Figge MT, Papenfort K, Fröhlich KS. The global RNA-RNA interactome of Klebsiella pneumoniae unveils a small RNA regulator of cell division. Proc Natl Acad Sci U S A 2024; 121:e2317322121. [PMID: 38377209 PMCID: PMC10907235 DOI: 10.1073/pnas.2317322121] [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: 10/09/2023] [Accepted: 01/18/2024] [Indexed: 02/22/2024] Open
Abstract
The ubiquitous RNA chaperone Hfq is involved in the regulation of key biological processes in many species across the bacterial kingdom. In the opportunistic human pathogen Klebsiella pneumoniae, deletion of the hfq gene affects the global transcriptome, virulence, and stress resistance; however, the ligands of the major RNA-binding protein in this species have remained elusive. In this study, we have combined transcriptomic, co-immunoprecipitation, and global RNA interactome analyses to compile an inventory of conserved and species-specific RNAs bound by Hfq and to monitor Hfq-mediated RNA-RNA interactions. In addition to dozens of RNA-RNA pairs, our study revealed an Hfq-dependent small regulatory RNA (sRNA), DinR, which is processed from the 3' terminal portion of dinI mRNA. Transcription of dinI is controlled by the master regulator of the SOS response, LexA. As DinR accumulates in K. pneumoniae in response to DNA damage, the sRNA represses translation of the ftsZ transcript by occupation of the ribosome binding site. Ectopic overexpression of DinR causes depletion of ftsZ mRNA and inhibition of cell division, while deletion of dinR antagonizes cell elongation in the presence of DNA damage. Collectively, our work highlights the important role of RNA-based gene regulation in K. pneumoniae and uncovers the central role of DinR in LexA-controlled division inhibition during the SOS response.
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Affiliation(s)
- Eric Ruhland
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University, Jena07743, Germany
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University, Jena07743, Germany
| | - Malte Siemers
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University, Jena07743, Germany
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University, Jena07743, Germany
| | - Ruman Gerst
- Faculty of Biological Sciences, Friedrich Schiller University, Jena07743, Germany
- Applied Systems Biology, Leibniz Institute for Natural Product Research and Infection Biology–Hans Knöll Institute, Jena07745, Germany
| | - Felix Späth
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University, Jena07743, Germany
| | - Laura Nicole Vogt
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University, Jena07743, Germany
| | - Marc Thilo Figge
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University, Jena07743, Germany
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University, Jena07743, Germany
- Applied Systems Biology, Leibniz Institute for Natural Product Research and Infection Biology–Hans Knöll Institute, Jena07745, Germany
| | - Kai Papenfort
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University, Jena07743, Germany
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University, Jena07743, Germany
| | - Kathrin Sophie Fröhlich
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University, Jena07743, Germany
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University, Jena07743, Germany
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5
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Edwards AN, McBride SM. The RgaS-RgaR two-component system promotes Clostridioides difficile sporulation through a small RNA and the Agr1 system. PLoS Genet 2023; 19:e1010841. [PMID: 37844084 PMCID: PMC10602386 DOI: 10.1371/journal.pgen.1010841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 10/26/2023] [Accepted: 10/02/2023] [Indexed: 10/18/2023] Open
Abstract
The ability to form a dormant spore is essential for the survival of the anaerobic pathogen, Clostridioides difficile, outside of the mammalian gastrointestinal tract. The initiation of sporulation is governed by the master regulator of sporulation, Spo0A, which is activated by phosphorylation. Multiple sporulation factors control Spo0A phosphorylation; however, this regulatory pathway is not well defined in C. difficile. We discovered that RgaS and RgaR, a conserved orphan histidine kinase and orphan response regulator, function together as a cognate two-component regulatory system to directly activate transcription of several genes. One of these targets, agrB1D1, encodes gene products that synthesize and export a small quorum-sensing peptide, AgrD1, which positively influences expression of early sporulation genes. Another target, a small regulatory RNA now known as SpoZ, impacts later stages of sporulation through a small hypothetical protein and an additional, unknown regulatory mechanism(s). Unlike Agr systems in many organisms, AgrD1 does not activate the RgaS-RgaR two-component system, and thus, is not responsible for autoregulating its own production. Altogether, we demonstrate that C. difficile utilizes a conserved two-component system that is uncoupled from quorum-sensing to promote sporulation through two distinct regulatory pathways.
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Affiliation(s)
- Adrianne N. Edwards
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, Georgia, United States of America
| | - Shonna M. McBride
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, Georgia, United States of America
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6
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Pensinger DA, Dobrila HA, Stevenson DM, Davis NM, Amador-Noguez D, Hryckowian AJ. Exogenous butyrate inhibits butyrogenic metabolism and alters expression of virulence genes in Clostridioides difficile. bioRxiv 2023:2023.07.06.548018. [PMID: 37461482 PMCID: PMC10350080 DOI: 10.1101/2023.07.06.548018] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
The gut microbiome engenders colonization resistance against the diarrheal pathogen Clostridioides difficile but the molecular basis of this colonization resistance is incompletely understood. A prominent class of gut microbiome-produced metabolites important for colonization resistance against C. difficile is short chain fatty acids (SCFAs). In particular, one SCFA (butyrate) decreases the fitness of C. difficile in vitro and is correlated with C. difficile-inhospitable gut environments, both in mice and in humans. Here, we demonstrate that butyrate-dependent growth inhibition in C. difficile occurs under conditions where C. difficile also produces butyrate as a metabolic end product. Furthermore, we show that exogenous butyrate is internalized into C. difficile cells, is incorporated into intracellular CoA pools where it is metabolized in a reverse (energetically unfavorable) direction to crotonyl-CoA and (S)-3-hydroxybutyryl-CoA and/or 4-hydroxybutyryl-CoA. This internalization of butyrate and reverse metabolic flow of butyrogenic pathway(s) in C. difficile coincides with alterations in toxin production and sporulation. Together, this work highlights butyrate as a signal of a C. difficile inhospitable environment to which C. difficile responds by producing its diarrheagenic toxins and producing environmentally-resistant spores necessary for transmission between hosts. These findings provide foundational data for understanding the molecular and genetic basis of how C. difficile growth is inhibited by butyrate and how butyrate serves as a signal to alter C. difficile virulence in the face of a highly competitive and dynamic gut environment.
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Affiliation(s)
- Daniel A. Pensinger
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Medical Microbiology & Immunology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Horia A. Dobrila
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Medical Microbiology & Immunology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - David M. Stevenson
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Nicole M. Davis
- Department of Medical Microbiology & Immunology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | | | - Andrew J. Hryckowian
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Medical Microbiology & Immunology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
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Edwards AN, McBride SM. The RgaS-RgaR two-component system promotes Clostridioides difficile sporulation through a small RNA and the Agr1 system. bioRxiv 2023:2023.06.26.546640. [PMID: 37425791 PMCID: PMC10327067 DOI: 10.1101/2023.06.26.546640] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
The ability to form a dormant spore is essential for the survival of the anaerobic, gastrointestinal pathogen Clostridioides difficile outside of the mammalian gastrointestinal tract. The initiation of sporulation is governed by the master regulator of sporulation, Spo0A, which is activated by phosphorylation. Multiple sporulation factors control Spo0A phosphorylation; however, this regulatory pathway is not well defined in C. difficile. We discovered that RgaS and RgaR, a conserved orphan histidine kinase and orphan response regulator, function together as a cognate two-component regulatory system to directly activate transcription of several genes. One of these targets, agrB1D1, encodes gene products that synthesize and export a small quorum-sensing peptide, AgrD1, which positively influences expression of early sporulation genes. Another target, a small regulatory RNA now known as SrsR, impacts later stages of sporulation through an unknown regulatory mechanism(s). Unlike Agr systems in many organisms, AgrD1 does not activate the RgaS-RgaR two-component system, and thus, is not responsible for autoregulating its own production. Altogether, we demonstrate that C. difficile utilizes a conserved two-component system that is uncoupled from quorum-sensing to promote sporulation through two distinct regulatory pathways.
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Affiliation(s)
- Adrianne N. Edwards
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, GA, USA
| | - Shonna M. McBride
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, GA, USA
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