1
|
Pi H, Carlin SM, Beavers WN, Hillebrand GH, Krystofiak ES, Stauff DL, Skaar EP. FapR regulates HssRS-mediated heme homeostasis in Bacillus anthracis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.08.602573. [PMID: 39026866 PMCID: PMC11257595 DOI: 10.1101/2024.07.08.602573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Bacillus anthracis, a Gram-positive facultative anaerobe and the causative agent of anthrax, multiplies to extraordinarily high numbers in vertebrate blood, resulting in considerable heme exposure. Heme is an essential nutrient and the preferred iron source for bacteria during vertebrate colonization, but its high redox potential makes it toxic in excess. To regulate heme homeostasis, many Gram-positive bacteria, including B. anthracis, rely on the two-component signaling system HssRS. HssRS comprises the heme sensing histidine kinase HssS, which modulates the activity of the HssR transcription factor to enable bacteria to circumvent heme toxicity. However, the regulation of the HssRS system remains unclear. Here we identify FapR, the transcriptional regulator of fatty acid biosynthesis, as a key factor in HssRS function. FapR plays an important role in maintaining membrane integrity and the localization of the histidine kinase HssS. Specifically, disruption of fapR leads to increased membrane rigidity, which hinders the penetration of HssRS inducers, resulting in the inactivation of HssRS. Furthermore, deletion of fapR affects the loading of HssS onto the cell membrane, compromising its heme sensing function and subsequently reducing endogenous heme biosynthesis. These findings shed light on the molecular mechanisms governing bacterial adaptation to heme stress and provide potential targets for antimicrobial intervention strategies.
Collapse
Affiliation(s)
- Hualiang Pi
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University, Nashville, TN
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, TN
- Current address: Department of Microbial Pathogenesis and Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT
| | - Sophia M. Carlin
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University, Nashville, TN
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, TN
| | - William N. Beavers
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University, Nashville, TN
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, TN
| | | | - Evan S. Krystofiak
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN
| | | | - Eric P. Skaar
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University, Nashville, TN
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, TN
| |
Collapse
|
2
|
Saillant V, Morey L, Lipuma D, Boëton P, Siponen M, Arnoux P, Lechardeur D. HssS activation by membrane heme defines a paradigm for two-component system signaling in Staphylococcus aureus. mBio 2024; 15:e0023024. [PMID: 38682935 PMCID: PMC11237747 DOI: 10.1128/mbio.00230-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 04/02/2024] [Indexed: 05/01/2024] Open
Abstract
Strict management of intracellular heme pools, which are both toxic and beneficial, is crucial for bacterial survival during infection. The human pathogen Staphylococcus aureus uses a two-component heme sensing system (HssRS), which counteracts environmental heme toxicity by triggering expression of the efflux transporter HrtBA. The HssS heme sensor is a HisKA-type histidine kinase, characterized as a membrane-bound homodimer containing an extracellular sensor and a cytoplasmic conserved catalytic domain. To elucidate HssS heme-sensing mechanism, a structural simulation of the HssS dimer based on Alphafold2 was docked with heme. In this model, a heme-binding site is present in the HssS dimer between the membrane and extracellular domains. Heme is embedded in the membrane bilayer with its two protruding porphyrin propionates interacting with two conserved Arg94 and Arg163 that are located extracellularly. Single substitutions of these arginines and two highly conserved phenylalanines, Phe25 and Phe128, in the predicted hydrophobic pocket limited the ability of HssS to induce HrtBA synthesis. Combination of the four substitutions abolished HssS activation. Wild-type (WT) HssS copurified with heme from Escherichia coli, whereas heme binding was strongly attenuated in the variants. This study gives evidence that exogenous heme interacts with HssS at the membrane/extracellular interface to initiate HssS activation and induce HrtBA-mediated heme extrusion from the membrane. This "gatekeeper" mechanism could limit intracellular diffusion of exogenous heme in S. aureus and may serve as a paradigm for how efflux transporters control detoxification of exogenous hydrophobic stressors.IMPORTANCEIn the host blood, pathogenic bacteria are exposed to the red pigment heme that concentrates in their lipid membranes, generating cytotoxicity. To overcome heme toxicity, Staphylococcus aureus expresses a membrane sensor protein, HssS. Activation of HssS by heme triggers a phosphotransfer mechanism leading to the expression of a heme efflux system, HrtBA. This detoxification system prevents intracellular accumulation of heme. Our structural and functional data reveal a heme-binding hydrophobic cavity in HssS within the transmembrane domains (TM) helices at the interface with the extracellular domain. This structural pocket is important for the function of HssS as a heme sensor. Our findings provide a new basis for the elucidation of pathogen-sensing mechanisms as a prerequisite to the discovery of inhibitors.
Collapse
Affiliation(s)
- Vincent Saillant
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France, Jouy-en-Josas, France
| | - Léo Morey
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France, Jouy-en-Josas, France
| | - Damien Lipuma
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France, Jouy-en-Josas, France
| | - Pierre Boëton
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France, Jouy-en-Josas, France
| | - Marina Siponen
- Aix Marseille Univ., CEA, CNRS, BIAM, Saint Paul-Lez-Durance, France
| | - Pascal Arnoux
- Aix Marseille Univ., CEA, CNRS, BIAM, Saint Paul-Lez-Durance, France
| | - Delphine Lechardeur
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France, Jouy-en-Josas, France
| |
Collapse
|
3
|
Ko YJ, Lee ME, Cho BH, Kim M, Hyeon JE, Han JH, Han SO. Bioproduction of porphyrins, phycobilins, and their proteins using microbial cell factories: engineering, metabolic regulations, challenges, and perspectives. Crit Rev Biotechnol 2024; 44:373-387. [PMID: 36775664 DOI: 10.1080/07388551.2023.2168512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 11/21/2022] [Accepted: 01/03/2023] [Indexed: 02/14/2023]
Abstract
Porphyrins, phycobilins, and their proteins have abundant π-electrons and strongly absorb visible light, some of which bind a metal ion in the center. Because of the structural and optical properties, they not only play critical roles as an essential component in natural systems but also have attracted much attention as a high value specialty chemical in various fields, including renewable energy, cosmetics, medicines, and foods. However, their commercial application seems to be still limited because the market price of porphyrins and phycobilins is generally expensive to apply them easily. Furthermore, their petroleum-based chemical synthesis is energy-intensive and emits a pollutant. Recently, to replace petroleum-based production, many studies on the bioproduction of metalloporphyrins, including Zn-porphyrin, Co-porphyrin, and heme, porphyrin derivatives including chlorophyll, biliverdin, and phycobilins, and their proteins including hemoproteins, phycobiliproteins, and phytochromes from renewable carbon sources using microbial cell factories have been reported. This review outlines recent advances in the bioproduction of porphyrins, phycobilins, and their proteins using microbial cell factories developed by various microbial biotechnology techniques, provides well-organized information on metabolic regulations of the porphyrin metabolism, and then critically discusses challenges and future perspectives. Through these, it is expected to be able to achieve possible solutions and insights and to develop an outstanding platform to be applied to the industry in future research.
Collapse
Affiliation(s)
- Young Jin Ko
- Department of Biotechnology, Korea University, Seoul, Republic of Korea
- Institute of Life Science and Natural Resources, Korea University, Seoul, Korea
| | - Myeong-Eun Lee
- Department of Biotechnology, Korea University, Seoul, Republic of Korea
| | - Byeong-Hyeon Cho
- Department of Biotechnology, Korea University, Seoul, Republic of Korea
| | - Minhye Kim
- Department of Biotechnology, Korea University, Seoul, Republic of Korea
| | - Jeong Eun Hyeon
- Department of Next Generation Applied Sciences, The Graduate School of Sungshin University, Seoul, Korea
- Department of Food Science and Biotechnology, College of Knowledge-Based Services Engineering, Sungshin Women's University, Seoul, Korea
| | - Joo Hee Han
- Department of Next Generation Applied Sciences, The Graduate School of Sungshin University, Seoul, Korea
- Department of Food Science and Biotechnology, College of Knowledge-Based Services Engineering, Sungshin Women's University, Seoul, Korea
| | - Sung Ok Han
- Department of Biotechnology, Korea University, Seoul, Republic of Korea
| |
Collapse
|
4
|
Leasure CS, Grunenwald CM, Choby JE, Sauer JD, Skaar EP. Maintenance of heme homeostasis in Staphylococcus aureus through post-translational regulation of glutamyl-tRNA reductase. J Bacteriol 2023; 205:e0017123. [PMID: 37655914 PMCID: PMC10521356 DOI: 10.1128/jb.00171-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 06/30/2023] [Indexed: 09/02/2023] Open
Abstract
Staphylococcus aureus is an important human pathogen responsible for a variety of infections including skin and soft tissue infections, endocarditis, and sepsis. The combination of increasing antibiotic resistance in this pathogen and the lack of an efficacious vaccine underscores the importance of understanding how S. aureus maintains metabolic homeostasis in a variety of environments, particularly during infection. Within the host, S. aureus must regulate cellular levels of the cofactor heme to support enzymatic activities without encountering heme toxicity. Glutamyl tRNA reductase (GtrR), the enzyme catalyzing the first committed step in heme synthesis, is an important regulatory node of heme synthesis in Bacteria, Archaea, and Plantae. In many organisms, heme status negatively regulates the abundance of GtrR, controlling flux through the heme synthesis pathway. We identified two residues within GtrR, H32 and R214, that are important for GtrR-heme binding. However, in strains expressing either GtrRH32A or GtrRR214A, heme homeostasis was not perturbed, suggesting an alternative mechanism of heme synthesis regulation occurs in S. aureus. In this regard, we report that heme synthesis is regulated through phosphorylation and dephosphorylation of GtrR by the serine/threonine kinase Stk1 and the phosphatase Stp1, respectively. Taken together, these results suggest that the mechanisms governing staphylococcal heme synthesis integrate both the availability of heme and the growth status of the cell. IMPORTANCE Staphylococcus aureus represents a significant threat to human health. Heme is an iron-containing enzymatic cofactor that can be toxic at elevated levels. During infection, S. aureus must control heme levels to replicate and survive within the hostile host environment. We identified residues within a heme biosynthetic enzyme that are critical for heme binding in vitro; however, abrogation of heme binding is not sufficient to perturb heme homeostasis within S. aureus. This marks a divergence from previously reported mechanisms of heme-dependent regulation of the highly conserved enzyme glutamyl tRNA reductase (GtrR). Additionally, we link cell growth arrest to the modulation of heme levels through the post-translational regulation of GtrR by the kinase Stk1 and the phosphatase Stp1.
Collapse
Affiliation(s)
- Catherine S. Leasure
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Caroline M. Grunenwald
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jacob E. Choby
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - John-Demian Sauer
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Eric P. Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| |
Collapse
|
5
|
Su H, Chen X, Chen S, Guo M, Liu H. Applications of the Whole-Cell System in the Efficient Biosynthesis of Heme. Int J Mol Sci 2023; 24:ijms24098384. [PMID: 37176091 PMCID: PMC10179345 DOI: 10.3390/ijms24098384] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 04/22/2023] [Accepted: 04/30/2023] [Indexed: 05/15/2023] Open
Abstract
Heme has a variety of functions, from electronic reactions to binding gases, which makes it useful in medical treatments, dietary supplements, and food processing. In recent years, whole-cell system-based heme biosynthesis methods have been continuously explored and optimized as an alternative to the low-yield, lasting, and adverse ecological environment of chemical synthesis methods. This method relies on two biosynthetic pathways of microbial precursor 5-aminolevulinic acid (C4, C5) and three known downstream biosynthetic pathways of heme. This paper reviews the genetic and metabolic engineering strategies for heme production in recent years by optimizing culture conditions and techniques from different microorganisms. Specifically, we summarized and analyzed the possibility of using biosensors to explore new strategies for the biosynthesis of heme from the perspective of synthetic biology, providing a new direction for future exploration.
Collapse
Affiliation(s)
- Hongfei Su
- School of Food and Health, Beijing Technology and Business University, Beijing 100048, China
| | - Xiaolin Chen
- School of Food and Health, Beijing Technology and Business University, Beijing 100048, China
| | - Shijing Chen
- School of Food and Health, Beijing Technology and Business University, Beijing 100048, China
| | - Mingzhang Guo
- School of Food and Health, Beijing Technology and Business University, Beijing 100048, China
| | - Huilin Liu
- School of Food and Health, Beijing Technology and Business University, Beijing 100048, China
| |
Collapse
|
6
|
Wassmann CS, Rolsted AP, Lyngsie MC, Puig ST, Kronborg T, Vestergaard M, Ingmer H, Pontoppidan SP, Klitgaard JK. The menaquinone pathway is important for susceptibility of Staphylococcus aureus to the antibiotic adjuvant, cannabidiol. Microbiol Res 2022; 257:126974. [DOI: 10.1016/j.micres.2022.126974] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 01/12/2023]
|
7
|
DnaJ and ClpX are required for HitRS and HssRS two-component system signaling in Bacillus anthracis. Infect Immun 2021; 90:e0056021. [PMID: 34748369 DOI: 10.1128/iai.00560-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus anthracis is the causative agent of anthrax. This Gram-positive bacterium poses a substantial risk to human health due to high mortality rates and the potential for malicious use as a bioterror weapon. To survive within the vertebrate host, B. anthracis relies on two-component system (TCS) signaling to sense host-induced stresses and respond to alterations in the environment through changes in target gene expression. HitRS and HssRS are cross-regulating TCSs in B. anthracis that respond to cell envelope disruptions and high heme levels, respectively. In this study, an unbiased and targeted genetic selection was designed to identify gene products that are involved in HitRS and HssRS signaling. This selection led to the identification of inactivating mutations within dnaJ and clpX that disrupt HitRS- and HssRS-dependent gene expression. DnaJ and ClpX are the substrate-binding subunits of the DnaJK protein chaperone and ClpXP protease, respectively. DnaJ regulates the levels of HitR and HitS to facilitate signal transduction, while ClpX specifically regulates HitS levels. Together these results reveal that the protein homeostasis regulators, DnaJ and ClpX, function to maintain B. anthracis signal transduction activities through TCS regulation. One sentence summary: Use of a genetic selection strategy to identify modulators of two-component system signaling in Bacillus anthracis.
Collapse
|
8
|
Simultaneous exposure to intracellular and extracellular photosensitizers for the treatment of Staphylococcus aureus infections. Antimicrob Agents Chemother 2021; 65:e0091921. [PMID: 34516248 DOI: 10.1128/aac.00919-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus is a serious threat to public health due to the rise of antibiotic resistance in this organism, which can prolong or exacerbate skin and soft tissue infections (SSTIs). Methicillin-resistant S. aureus is a Gram-positive bacterium and a leading cause of SSTIs. As such, many efforts are underway to develop therapies that target essential biological processes in S. aureus. Antimicrobial photodynamic therapy is effective alternative to antibiotics, therefore we developed an approach to simultaneously expose S. aureus to intracellular and extracellular photoactivators. A near infrared photosensitizer was conjugated to human monoclonal antibodies (mAbs) that target the S. aureus Isd heme acquisition proteins. Additionally, the compound VU0038882 was developed to increase photoactivatable porphyrins within the cell. Combinatorial PDT treatment of drug-resistant S. aureus exposed to VU0038882 and conjugated anti-Isd mAbs proved to be an effective antibacterial strategy in vitro and in a murine model of SSTIs.
Collapse
|
9
|
Schrader SM, Vaubourgeix J, Nathan C. Biology of antimicrobial resistance and approaches to combat it. Sci Transl Med 2021; 12:12/549/eaaz6992. [PMID: 32581135 DOI: 10.1126/scitranslmed.aaz6992] [Citation(s) in RCA: 90] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 02/12/2020] [Indexed: 12/14/2022]
Abstract
Insufficient development of new antibiotics and the rising resistance of bacteria to those that we have are putting the world at risk of losing the most widely curative class of medicines currently available. Preventing deaths from antimicrobial resistance (AMR) will require exploiting emerging knowledge not only about genetic AMR conferred by horizontal gene transfer or de novo mutations but also about phenotypic AMR, which lacks a stably heritable basis. This Review summarizes recent advances and continuing limitations in our understanding of AMR and suggests approaches for combating its clinical consequences, including identification of previously unexploited bacterial targets, new antimicrobial compounds, and improved combination drug regimens.
Collapse
Affiliation(s)
- Sarah M Schrader
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Julien Vaubourgeix
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Carl Nathan
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY 10065, USA.
| |
Collapse
|
10
|
Das M, Dewan A, Shee S, Singh A. The Multifaceted Bacterial Cysteine Desulfurases: From Metabolism to Pathogenesis. Antioxidants (Basel) 2021; 10:antiox10070997. [PMID: 34201508 PMCID: PMC8300815 DOI: 10.3390/antiox10070997] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/01/2021] [Accepted: 05/06/2021] [Indexed: 12/02/2022] Open
Abstract
Living cells have developed a relay system to efficiently transfer sulfur (S) from cysteine to various thio-cofactors (iron-sulfur (Fe-S) clusters, thiamine, molybdopterin, lipoic acid, and biotin) and thiolated tRNA. The presence of such a transit route involves multiple protein components that allow the flux of S to be precisely regulated as a function of environmental cues to avoid the unnecessary accumulation of toxic concentrations of soluble sulfide (S2−). The first enzyme in this relay system is cysteine desulfurase (CSD). CSD catalyzes the release of sulfane S from L-cysteine by converting it to L-alanine by forming an enzyme-linked persulfide intermediate on its conserved cysteine residue. The persulfide S is then transferred to diverse acceptor proteins for its incorporation into the thio-cofactors. The thio-cofactor binding-proteins participate in essential and diverse cellular processes, including DNA repair, respiration, intermediary metabolism, gene regulation, and redox sensing. Additionally, CSD modulates pathogenesis, antibiotic susceptibility, metabolism, and survival of several pathogenic microbes within their hosts. In this review, we aim to comprehensively illustrate the impact of CSD on bacterial core metabolic processes and its requirement to combat redox stresses and antibiotics. Targeting CSD in human pathogens can be a potential therapy for better treatment outcomes.
Collapse
|
11
|
Hübner I, Shapiro JA, Hoßmann J, Drechsel J, Hacker SM, Rather PN, Pieper DH, Wuest WM, Sieber SA. Broad Spectrum Antibiotic Xanthocillin X Effectively Kills Acinetobacter baumannii via Dysregulation of Heme Biosynthesis. ACS CENTRAL SCIENCE 2021; 7:488-498. [PMID: 33791430 PMCID: PMC8006170 DOI: 10.1021/acscentsci.0c01621] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Indexed: 05/19/2023]
Abstract
Isonitrile natural products exhibit promising antibacterial activities. However, their mechanism of action (MoA) remains largely unknown. Based on the nanomolar potency of xanthocillin X (Xan) against diverse difficult-to-treat Gram-negative bacteria, including the critical priority pathogen Acinetobacter baumannii, we performed in-depth studies to decipher its MoA. While neither metal binding nor cellular protein targets were detected as relevant for Xan's antibiotic effects, sequencing of resistant strains revealed a conserved mutation in the heme biosynthesis enzyme porphobilinogen synthase (PbgS). This mutation caused impaired enzymatic efficiency indicative of reduced heme production. This discovery led to the validation of an untapped mechanism, by which direct heme sequestration of Xan prevents its binding into cognate enzyme pockets resulting in uncontrolled cofactor biosynthesis, accumulation of porphyrins, and corresponding stress with deleterious effects for bacterial viability. Thus, Xan represents a promising antibiotic displaying activity even against multidrug resistant strains, while exhibiting low toxicity to human cells.
Collapse
Affiliation(s)
- Ines Hübner
- Center
for Functional Protein Assemblies at the Department of Chemistry and
Chair of Organic Chemistry II, Technische
Universität München, Garching D-85748, Germany
| | - Justin A. Shapiro
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Jörn Hoßmann
- Microbial
Interactions and Processes Research Group, Helmholtz Centre for Infection Research, Braunschweig 38124, Germany
| | - Jonas Drechsel
- Center
for Functional Protein Assemblies at the Department of Chemistry and
Chair of Organic Chemistry II, Technische
Universität München, Garching D-85748, Germany
| | - Stephan M. Hacker
- Department
of Chemistry, Technische Universität
München, Garching D-85748, Germany
| | - Philip N. Rather
- Emory Antibiotic Resistance Center and Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia 30322, United States
- Research
Service, Atlanta VA Medical Center, Decatur, Georgia 30033, United States
| | - Dietmar H. Pieper
- Microbial
Interactions and Processes Research Group, Helmholtz Centre for Infection Research, Braunschweig 38124, Germany
| | - William M. Wuest
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
- Emory Antibiotic Resistance Center and Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - Stephan A. Sieber
- Center
for Functional Protein Assemblies at the Department of Chemistry and
Chair of Organic Chemistry II, Technische
Universität München, Garching D-85748, Germany
| |
Collapse
|
12
|
Shin M, Jin Y, Park J, Mun D, Kim SR, Payne SM, Kim KH, Kim Y. Characterization of an Antibacterial Agent Targeting Ferrous Iron Transport Protein FeoB against Staphylococcus aureus and Gram-Positive Bacteria. ACS Chem Biol 2021; 16:136-149. [PMID: 33378170 DOI: 10.1021/acschembio.0c00842] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The emergence of multidrug-resistant Staphylococcus aureus strains has become a serious clinical problem. Iron is absolutely required for the bacterial growth, virulence associated with colonization, and survival from the host immune system. The FeoB protein is a major iron permease in bacterial ferrous iron transport systems (Feo) that has been shown to play a crucial role in virulence of some pathogenic bacteria. However, FeoB is still uncharacterized in Gram-positive pathogens, and its effects on S. aureus pathogenesis are unknown. In this study, we identified a novel inhibitor, GW3965·HCl, that targets FeoB in S. aureus. The molecule effectively inhibited FeoB in vitro enzyme activity, bacterial growth, and virulence factor expression. Genome-editing and metabolomic analyses revealed that GW3965·HCl inhibited FeoB function and affected the associated mechanisms with reduced iron availability in S. aureus. Gentamicin resistance and Caenorhabditis elegans infection assays further demonstrated the power of GW3965·HCl as a safe and efficient antibacterial agent. In addition to S. aureus, GW3965·HCl also presented its effectiveness on inhibition of the FeoB activity and growth of Gram-positive bacteria. This novel inhibitor will provide new insight for developing a next-generation antibacterial therapy.
Collapse
Affiliation(s)
- Minhye Shin
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841, Republic of Korea
- Department of Agricultural Biotechnology, Research Institute of Agriculture and Life Science, Seoul National University, Seoul, 08826, Republic of Korea
| | - Yerin Jin
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841, Republic of Korea
| | - Jinsub Park
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841, Republic of Korea
| | - Daye Mun
- Department of Agricultural Biotechnology, Research Institute of Agriculture and Life Science, Seoul National University, Seoul, 08826, Republic of Korea
| | - Soo Rin Kim
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Shelley M. Payne
- Department of Molecular Biosciences, College of Natural Science, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Kyoung Heon Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841, Republic of Korea
| | - Younghoon Kim
- Department of Agricultural Biotechnology, Research Institute of Agriculture and Life Science, Seoul National University, Seoul, 08826, Republic of Korea
| |
Collapse
|
13
|
Pi H, Chu ML, Ivan SJ, Latario CJ, Toth AM, Carlin SM, Hillebrand GH, Lin HK, Reppart JD, Stauff DL, Skaar EP. Directed evolution reveals the mechanism of HitRS signaling transduction in Bacillus anthracis. PLoS Pathog 2020; 16:e1009148. [PMID: 33362282 PMCID: PMC7790381 DOI: 10.1371/journal.ppat.1009148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 01/07/2021] [Accepted: 11/11/2020] [Indexed: 12/03/2022] Open
Abstract
Two component systems (TCSs) are a primary mechanism of signal sensing and response in bacteria. Systematic characterization of an entire TCS could provide a mechanistic understanding of these important signal transduction systems. Here, genetic selections were employed to dissect the molecular basis of signal transduction by the HitRS system that detects cell envelope stress in the pathogen Bacillus anthracis. Numerous point mutations were isolated within HitRS, 17 of which were in a 50-residue HAMP domain. Mutational analysis revealed the importance of hydrophobic interactions within the HAMP domain and highlighted its essentiality in TCS signaling. In addition, these data defined residues critical for activities intrinsic to HitRS, uncovered specific interactions among individual domains and between the two signaling proteins, and revealed that phosphotransfer is the rate-limiting step for signal transduction. Furthermore, this study establishes the use of unbiased genetic selections to study TCS signaling and provides a comprehensive mechanistic understanding of an entire TCS. Bacterial TCSs are a primary strategy for stress sensing and niche adaptation. Although individual domains and proteins of these systems have been extensively studied, systematic characterization of an entire TCS is rare. In this study, through unbiased genetic selections and rigorous biochemical analysis, we provide a detailed characterization and structure-function analysis of an entire TCS and extend our understanding of the molecular basis of signal transduction through TCSs. Moreover, this study provides a comprehensive map of point-mutations in these well-conserved signaling proteins, which will be broadly useful for studying other TCSs. The described genetic selection strategies are applicable to any TCS, providing a powerful tool for researchers interested in microbial signal transduction.
Collapse
Affiliation(s)
- Hualiang Pi
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute for Infection, Immunology, & Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Michelle L. Chu
- Department of Biology, Grove City College, Grove City, Pennsylvania, United States of America
| | - Samuel J. Ivan
- Department of Biology, Grove City College, Grove City, Pennsylvania, United States of America
| | - Casey J. Latario
- Department of Biology, Grove City College, Grove City, Pennsylvania, United States of America
| | - Allen M. Toth
- Department of Biology, Grove City College, Grove City, Pennsylvania, United States of America
| | - Sophia M. Carlin
- Department of Biology, Grove City College, Grove City, Pennsylvania, United States of America
| | - Gideon H. Hillebrand
- Department of Biology, Grove City College, Grove City, Pennsylvania, United States of America
| | - Hannah K. Lin
- Department of Biology, Grove City College, Grove City, Pennsylvania, United States of America
| | - Jared D. Reppart
- Department of Biology, Grove City College, Grove City, Pennsylvania, United States of America
| | - Devin L. Stauff
- Department of Biology, Grove City College, Grove City, Pennsylvania, United States of America
| | - Eric P. Skaar
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute for Infection, Immunology, & Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- * E-mail:
| |
Collapse
|
14
|
Host nutrient milieu drives an essential role for aspartate biosynthesis during invasive Staphylococcus aureus infection. Proc Natl Acad Sci U S A 2020; 117:12394-12401. [PMID: 32414924 PMCID: PMC7275739 DOI: 10.1073/pnas.1922211117] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Staphylococcus aureus can infect a diverse array of host environments. The broad tissue tropism of S. aureus requires metabolic flexibility to utilize the variety of nutrient sources found within target organ systems. In this work, we conducted a systematic analysis of the central metabolic pathways required for S. aureus survival during bone infection, one of the most frequent sites of invasive staphylococcal disease. We show that S. aureus requires aspartate biosynthesis to survive during bone infection, despite possessing an aspartate transporter, due to inhibition of aspartate utilization by the amino acid glutamate. Our results reveal a crucial role for inflammation-associated shifts in the host nutrient milieu for determining the metabolic pathways utilized by S. aureus during invasive infection. The bacterial pathogen Staphylococcus aureus is capable of infecting a broad spectrum of host tissues, in part due to flexibility of metabolic programs. S. aureus, like all organisms, requires essential biosynthetic intermediates to synthesize macromolecules. We therefore sought to determine the metabolic pathways contributing to synthesis of essential precursors during invasive S. aureus infection. We focused specifically on staphylococcal infection of bone, one of the most common sites of invasive S. aureus infection and a unique environment characterized by dynamic substrate accessibility, infection-induced hypoxia, and a metabolic profile skewed toward aerobic glycolysis. Using a murine model of osteomyelitis, we examined survival of S. aureus mutants deficient in central metabolic pathways, including glycolysis, gluconeogenesis, the tricarboxylic acid (TCA) cycle, and amino acid synthesis/catabolism. Despite the high glycolytic demand of skeletal cells, we discovered that S. aureus requires glycolysis for survival in bone. Furthermore, the TCA cycle is dispensable for survival during osteomyelitis, and S. aureus instead has a critical need for anaplerosis. Bacterial synthesis of aspartate in particular is absolutely essential for staphylococcal survival in bone, despite the presence of an aspartate transporter, which we identified as GltT and confirmed biochemically. This dependence on endogenous aspartate synthesis derives from the presence of excess glutamate in infected tissue, which inhibits aspartate acquisition by S. aureus. Together, these data elucidate the metabolic pathways required for staphylococcal infection within bone and demonstrate that the host nutrient milieu can determine essentiality of bacterial nutrient biosynthesis pathways despite the presence of dedicated transporters.
Collapse
|
15
|
Zhang L, Hendrickson RC, Meikle V, Lefkowitz EJ, Ioerger TR, Niederweis M. Comprehensive analysis of iron utilization by Mycobacterium tuberculosis. PLoS Pathog 2020; 16:e1008337. [PMID: 32069330 PMCID: PMC7058343 DOI: 10.1371/journal.ppat.1008337] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 03/05/2020] [Accepted: 01/20/2020] [Indexed: 12/16/2022] Open
Abstract
Iron is essential for nearly all bacterial pathogens, including Mycobacterium tuberculosis (Mtb), but is severely limited in the human host. To meet its iron needs, Mtb secretes siderophores, small molecules with high affinity for iron, and takes up iron-loaded mycobactins (MBT) and carboxymycobactins (cMBT), from the environment. Mtb is also capable of utilizing heme and hemoglobin which contain more than 70% of the iron in the human body. However, many components of these iron acquisition pathways are still unknown. In this study, a high-density transposon mutagenesis coupled with deep sequencing (TnSeq) showed that Mtb exhibits nearly opposite requirements for 165 genes in the presence of heme and hemoglobin versus MBT and cMBT as iron sources. The ESX-3 secretion system was assessed as essential for siderophore-mediated iron uptake and, surprisingly, also for heme utilization by Mtb. Predictions derived from the TnSeq analysis were validated by growth experiments with isogenic Mtb mutants. These results showed that (i) the efflux pump MmpL5 plays a dominant role in siderophore secretion, (ii) the Rv2047c protein is essential for growth of Mtb in the presence of mycobactin, and (iii) the transcriptional repressor Zur is required for heme utilization by Mtb. The novel genetic determinants of iron utilization revealed in this study will stimulate further experiments in this important area of Mtb physiology.
Collapse
Affiliation(s)
- Lei Zhang
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - R. Curtis Hendrickson
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Virginia Meikle
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Elliot J. Lefkowitz
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Thomas R. Ioerger
- Department of Computer Science and Engineering, Texas A&M University, College Station, Texas, United States of America
| | - Michael Niederweis
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| |
Collapse
|
16
|
Reker D, Bernardes GJL, Rodrigues T. Computational advances in combating colloidal aggregation in drug discovery. Nat Chem 2019; 11:402-418. [PMID: 30988417 DOI: 10.1038/s41557-019-0234-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 02/21/2019] [Indexed: 02/07/2023]
Abstract
Small molecule effectors are essential for drug discovery. Specific molecular recognition, reversible binding and dose-dependency are usually key requirements to ensure utility of a novel chemical entity. However, artefactual frequent-hitter and assay interference compounds may divert lead optimization and screening programmes towards attrition-prone chemical matter. Colloidal aggregates are the prime source of false positive readouts, either through protein sequestration or protein-scaffold mimicry. Nevertheless, assessment of colloidal aggregation remains somewhat overlooked and under-appreciated. In this Review, we discuss the impact of aggregation in drug discovery by analysing select examples from the literature and publicly-available datasets. We also examine and comment on technologies used to experimentally identify these potentially problematic entities. We focus on evidence-based computational filters and machine learning algorithms that may be swiftly deployed to flag chemical matter and mitigate the impact of aggregates in discovery programmes. We highlight the tools that can be used to scrutinize libraries, and identify and eliminate these problematic compounds.
Collapse
Affiliation(s)
- Daniel Reker
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. .,Division of Gastroenterology, Hepatology and Endoscopy, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA. .,MIT-IBM Watson AI Lab, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Gonçalo J L Bernardes
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK.,Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Lisboa, Portugal
| | - Tiago Rodrigues
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Lisboa, Portugal.
| |
Collapse
|
17
|
Choby JE, Grunenwald CM, Celis AI, Gerdes SY, DuBois JL, Skaar EP. Staphylococcus aureus HemX Modulates Glutamyl-tRNA Reductase Abundance To Regulate Heme Biosynthesis. mBio 2018; 9:e02287-17. [PMID: 29437922 PMCID: PMC5801465 DOI: 10.1128/mbio.02287-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 01/08/2018] [Indexed: 12/30/2022] Open
Abstract
Staphylococcus aureus is responsible for a significant amount of devastating disease. Its ability to colonize the host and cause infection is supported by a variety of proteins that are dependent on the cofactor heme. Heme is a porphyrin used broadly across kingdoms and is synthesized de novo from common cellular precursors and iron. While heme is critical to bacterial physiology, it is also toxic in high concentrations, requiring that organisms encode regulatory processes to control heme homeostasis. In this work, we describe a posttranscriptional regulatory strategy in S. aureus heme biosynthesis. The first committed enzyme in the S. aureus heme biosynthetic pathway, glutamyl-tRNA reductase (GtrR), is regulated by heme abundance and the integral membrane protein HemX. GtrR abundance increases dramatically in response to heme deficiency, suggesting a mechanism by which S. aureus responds to the need to increase heme synthesis. Additionally, HemX is required to maintain low levels of GtrR in heme-proficient cells, and inactivation of hemX leads to increased heme synthesis. Excess heme synthesis in a ΔhemX mutant activates the staphylococcal heme stress response, suggesting that regulation of heme synthesis is critical to reduce self-imposed heme toxicity. Analysis of diverse organisms indicates that HemX is widely conserved among heme-synthesizing bacteria, suggesting that HemX is a common factor involved in the regulation of GtrR abundance. Together, this work demonstrates that S. aureus regulates heme synthesis by modulating GtrR abundance in response to heme deficiency and through the activity of the broadly conserved HemX.IMPORTANCEStaphylococcus aureus is a leading cause of skin and soft tissue infections, endocarditis, bacteremia, and osteomyelitis, making it a critical health care concern. Development of new antimicrobials against S. aureus requires knowledge of the physiology that supports this organism's pathogenesis. One component of staphylococcal physiology that contributes to growth and virulence is heme. Heme is a widely utilized cofactor that enables diverse chemical reactions across many enzyme families. S. aureus relies on many critical heme-dependent proteins and is sensitive to excess heme toxicity, suggesting S. aureus must maintain proper intracellular heme homeostasis. Because S. aureus provides heme for heme-dependent enzymes via synthesis from common precursors, we hypothesized that regulation of heme synthesis is one mechanism to maintain heme homeostasis. In this study, we identify that S. aureus posttranscriptionally regulates heme synthesis by restraining abundance of the first heme biosynthetic enzyme, GtrR, via heme and the broadly conserved membrane protein HemX.
Collapse
Affiliation(s)
- Jacob E Choby
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Graduate Program in Microbiology & Immunology, Vanderbilt University, Nashville, Tennessee, USA
| | - Caroline M Grunenwald
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Arianna I Celis
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | | | - Jennifer L DuBois
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| |
Collapse
|
18
|
Lojek LJ, Farrand AJ, Weiss A, Skaar EP. Fur regulation of Staphylococcus aureus heme oxygenases is required for heme homeostasis. Int J Med Microbiol 2018; 308:582-589. [PMID: 29409696 DOI: 10.1016/j.ijmm.2018.01.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 01/04/2018] [Accepted: 01/27/2018] [Indexed: 01/23/2023] Open
Abstract
Heme is a cofactor that is essential for cellular respiration and for the function of many enzymes. If heme levels become too low within the cell, S. aureus switches from producing energy via respiration to producing energy by fermentation. S. aureus encodes two heme oxygenases, IsdI and IsdG, which cleave the porphyrin heme ring releasing iron for use as a nutrient source. Both isdI and isdG are only expressed under low iron conditions and are regulated by the canonical Ferric Uptake Regulator (Fur). Here we demonstrate that unregulated expression of isdI and isdG within S. aureus leads to reduced growth under low iron conditions. Additionally, the constitutive expression of these enzymes leads to decreased heme abundance in S. aureus, an increase in the fermentation product lactate, and increased resistance to gentamicin. This work demonstrates that S. aureus has developed tuning mechanisms, such as Fur regulation, to ensure that the cell has sufficient quantities of heme for efficient ATP production through aerobic respiration.
Collapse
Affiliation(s)
- Lisa J Lojek
- Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA; Graduate Program in Microbiology & Immunology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Allison J Farrand
- Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Andy Weiss
- Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
| |
Collapse
|
19
|
Weiss A, Fleeman RM, Shaw LN. Exposing the Unique Connection between Metabolism and Virulence in Staphylococcus aureus. Cell Chem Biol 2017; 23:1317-1319. [PMID: 27863216 DOI: 10.1016/j.chembiol.2016.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In this issue of Cell Chemical Biology, Choby et al. (2016) use a small molecule inhibitor active against fermenting S. aureus to unravel a unique connection between virulence factor production and central metabolism. In so doing, the authors uncover Fe-S cluster assembly proteins as a novel antibacterial target, and deliver a first-in-class scaffold for optimization against anaerobically growing cells.
Collapse
Affiliation(s)
- Andy Weiss
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, 4202 East Fowler Avenue, ISA 2015, Tampa, FL 33620, USA
| | - Renee M Fleeman
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, 4202 East Fowler Avenue, ISA 2015, Tampa, FL 33620, USA
| | - Lindsey N Shaw
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, 4202 East Fowler Avenue, ISA 2015, Tampa, FL 33620, USA.
| |
Collapse
|
20
|
Antibacterial photosensitization through activation of coproporphyrinogen oxidase. Proc Natl Acad Sci U S A 2017; 114:E6652-E6659. [PMID: 28739897 DOI: 10.1073/pnas.1700469114] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Gram-positive bacteria cause the majority of skin and soft tissue infections (SSTIs), resulting in the most common reason for clinic visits in the United States. Recently, it was discovered that Gram-positive pathogens use a unique heme biosynthesis pathway, which implicates this pathway as a target for development of antibacterial therapies. We report here the identification of a small-molecule activator of coproporphyrinogen oxidase (CgoX) from Gram-positive bacteria, an enzyme essential for heme biosynthesis. Activation of CgoX induces accumulation of coproporphyrin III and leads to photosensitization of Gram-positive pathogens. In combination with light, CgoX activation reduces bacterial burden in murine models of SSTI. Thus, small-molecule activation of CgoX represents an effective strategy for the development of light-based antimicrobial therapies.
Collapse
|
21
|
A quinolinol-based small molecule with anti-MRSA activity that targets bacterial membrane and promotes fermentative metabolism. J Antibiot (Tokyo) 2017; 70:1009-1019. [PMID: 28698673 PMCID: PMC5621627 DOI: 10.1038/ja.2017.79] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 06/10/2017] [Accepted: 06/19/2017] [Indexed: 01/08/2023]
Abstract
In a loss-of-viability screen of small molecules against methicillin resistant S. aureus (MRSA) USA300, we found a small molecule, designated DNAC-2, which has an MIC of 8 μg/ml. DNAC-2 is a quinolinol derivative that is bactericidal at 2X MIC. Macromolecular synthesis assays at 2X MIC of DNAC-2 inhibited DNA, cell wall, RNA and protein synthesis within fifteen to thirty minutes of treatment when compared to the untreated control. Transmission electron microscopy of DNAC-2 treated cells revealed a significantly thicker cell wall and impaired daughter cell separation. Exposure of USA300 cells to 1X MIC of DNAC-2 resulted in mislocalization of PBP2 away from the septum in an FtsZ independent manner. In addition, membrane localization with FM4-64, as well as depolarization study with DiOC2 and lipophilic cation TPP+ displayed membrane irregularities and rapid membrane depolarization in DNAC-2 treated cells vs. untreated control. However, DNAC-2 exhibited almost no toxicity towards eukaryotic membranes. Notably, DNAC-2 drives energy generation towards substrate level phosphorylation and the bacteria become more sensitive to DNAC-2 under anaerobic conditions. We propose that DNAC-2 affects USA300 by targeting the membrane, leading to partial membrane depolarization and subsequently affecting aerobic respiration and energy-dependent functional organization of macromolecular biosynthetic pathways. The multiple effects may have the desirable consequence of limiting the emergence of resistance to DNAC-2.
Collapse
|
22
|
Zhang P, Wright JA, Osman AA, Nair SP. An aroD Ochre Mutation Results in a Staphylococcus aureus Small Colony Variant That Can Undergo Phenotypic Switching via Two Alternative Mechanisms. Front Microbiol 2017; 8:1001. [PMID: 28620368 PMCID: PMC5449664 DOI: 10.3389/fmicb.2017.01001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 05/18/2017] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus can undergo phenotypic switching between a normal colony phenotype (NCP) and a small colony variant (SCV). The SCV phenotype confers increased antibiotic resistance and the capacity to persist within human tissues and cells, and because these cells can revert back to the NCP they cause chronic and/or recurrent infections that are very difficult to treat. A complete picture of the genetic events that can lead to phenotypic switching in S. aureus is currently lacking. We describe the selection of an SCV with a previously unreported genetic alteration leading to an ochre mutation of aroD. In addition to the known mechanisms of phenotypic switching between the SCV and the NCP we describe a previously unreported mechanism involving tRNA ochre suppressors arising. The ochre suppressor strains had wild-type growth rates and restored antibiotic sensitivity, similar to the wild-type strain. However, whilst they had increased virulence compared to the SCV parent strain, their virulence was not restored to that of the NCP parental strain. These findings establish that phenotypic switching between the NCP and SCV states can give rise to strains with different pathogenic potential.
Collapse
Affiliation(s)
- Ping Zhang
- Department of Microbial Diseases, UCL Eastman Dental Institute, University College LondonLondon, United Kingdom
| | - John A Wright
- Immunology Catalyst, GlaxoSmithKline plcStevenage, United Kingdom
| | - Ahmed A Osman
- Department of Microbial Diseases, UCL Eastman Dental Institute, University College LondonLondon, United Kingdom
| | - Sean P Nair
- Department of Microbial Diseases, UCL Eastman Dental Institute, University College LondonLondon, United Kingdom
| |
Collapse
|
23
|
Moses AS, Millar JA, Bonazzi M, Beare PA, Raghavan R. Horizontally Acquired Biosynthesis Genes Boost Coxiella burnetii's Physiology. Front Cell Infect Microbiol 2017; 7:174. [PMID: 28540258 PMCID: PMC5423948 DOI: 10.3389/fcimb.2017.00174] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 04/21/2017] [Indexed: 01/21/2023] Open
Abstract
Coxiella burnetii, the etiologic agent of acute Q fever and chronic endocarditis, has a unique biphasic life cycle, which includes a metabolically active intracellular form that occupies a large lysosome-derived acidic vacuole. C. burnetii is the only bacterium known to thrive within such an hostile intracellular niche, and this ability is fundamental to its pathogenicity; however, very little is known about genes that facilitate Coxiella's intracellular growth. Recent studies indicate that C. burnetii evolved from a tick-associated ancestor and that the metabolic capabilities of C. burnetii are different from that of Coxiella-like bacteria found in ticks. Horizontally acquired genes that allow C. burnetii to infect and grow within mammalian cells likely facilitated the host shift; however, because of its obligate intracellular replication, C. burnetii would have lost most genes that have been rendered redundant due to the availability of metabolites within the host cell. Based on these observations, we reasoned that horizontally derived biosynthetic genes that have been retained in the reduced genome of C. burnetii are ideal candidates to begin to uncover its intracellular metabolic requirements. Our analyses identified a large number of putative foreign-origin genes in C. burnetii, including tRNAGlu2 that is potentially required for heme biosynthesis, and genes involved in the production of lipopolysaccharide—a virulence factor, and of critical metabolites such as fatty acids and biotin. In comparison to wild-type C. burnetii, a strain that lacks tRNAGlu2 exhibited reduced growth, indicating its importance to Coxiella's physiology. Additionally, by using chemical agents that block heme and biotin biosyntheses, we show that these pathways are promising targets for the development of new anti-Coxiella therapies.
Collapse
Affiliation(s)
- Abraham S Moses
- Department of Biology and Center for Life in Extreme Environments, Portland State UniversityPortland, OR, USA
| | - Jess A Millar
- Department of Biology and Center for Life in Extreme Environments, Portland State UniversityPortland, OR, USA
| | - Matteo Bonazzi
- Centre National de la Recherche Scientifique, Formation de Recherche en Évolution 3689, Centre d'Études d'Agents Pathogènes et Biotechnologies Pour la Santé, Université MontpellierMontpellier, France
| | - Paul A Beare
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institutes of HealthHamilton, MT, USA
| | - Rahul Raghavan
- Department of Biology and Center for Life in Extreme Environments, Portland State UniversityPortland, OR, USA
| |
Collapse
|
24
|
Visualization of the role of host heme on the virulence of the heme auxotroph Streptococcus agalactiae. Sci Rep 2017; 7:40435. [PMID: 28091535 PMCID: PMC5238366 DOI: 10.1038/srep40435] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 12/06/2016] [Indexed: 12/21/2022] Open
Abstract
Heme is essential for several cellular key functions but is also toxic. Whereas most bacterial pathogens utilize heme as a metabolic cofactor and iron source, the impact of host heme during bacterial infection remains elusive. The opportunist pathogen Streptococcus agalactiae does not synthesize heme but still uses it to activate a respiration metabolism. Concomitantly, heme toxicity is mainly controlled by the HrtBA efflux transporter. Here we investigate how S. agalactiae manages heme toxicity versus benefits in the living host. Using bioluminescent bacteria and heme-responsive reporters for in vivo imaging, we show that the capacity of S. agalactiae to overcome heme toxicity is required for successful infection, particularly in blood-rich organs. Host heme is simultaneously required, as visualized by a generalized infection defect of a respiration-negative mutant. In S. agalactiae, HrtBA expression responds to an intracellular heme signal via activation of the two-component system HssRS. A hssRS promoter-driven intracellular luminescent heme sensor was designed to identify host compartments that supply S. agalactiae with heme. S. agalactiae acquires heme in heart, kidneys, and liver, but not in the brain. We conclude that S. agalactiae response to heme is organ-dependent, and its efflux may be particularly relevant in late stages of infection.
Collapse
|
25
|
Choby JE, Mike LA, Mashruwala AA, Dutter BF, Dunman PM, Sulikowski GA, Boyd JM, Skaar EP. A Small-Molecule Inhibitor of Iron-Sulfur Cluster Assembly Uncovers a Link between Virulence Regulation and Metabolism in Staphylococcus aureus. Cell Chem Biol 2016; 23:1351-1361. [PMID: 27773628 DOI: 10.1016/j.chembiol.2016.09.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 09/01/2016] [Accepted: 09/30/2016] [Indexed: 11/28/2022]
Abstract
The rising problem of antimicrobial resistance in Staphylococcus aureus necessitates the discovery of novel therapeutic targets for small-molecule intervention. A major obstacle of drug discovery is identifying the target of molecules selected from high-throughput phenotypic assays. Here, we show that the toxicity of a small molecule termed '882 is dependent on the constitutive activity of the S. aureus virulence regulator SaeRS, uncovering a link between virulence factor production and energy generation. A series of genetic, physiological, and biochemical analyses reveal that '882 inhibits iron-sulfur (Fe-S) cluster assembly most likely through inhibition of the Suf complex, which synthesizes Fe-S clusters. In support of this, '882 supplementation results in decreased activity of the Fe-S cluster-dependent enzyme aconitase. Further information regarding the effects of '882 has deepened our understanding of virulence regulation and demonstrates the potential for small-molecule modulation of Fe-S cluster assembly in S. aureus and other pathogens.
Collapse
Affiliation(s)
- Jacob E Choby
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Graduate Program in Microbiology & Immunology, Vanderbilt University, Nashville, TN 37232, USA
| | - Laura A Mike
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Ameya A Mashruwala
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ 08901, USA
| | - Brendan F Dutter
- Department of Chemistry, Vanderbilt Institute for Chemical Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Paul M Dunman
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Gary A Sulikowski
- Department of Chemistry, Vanderbilt Institute for Chemical Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Jeffrey M Boyd
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ 08901, USA.
| | - Eric P Skaar
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Veterans Affairs Tennessee Valley Healthcare Services, Nashville, TN 37232, USA.
| |
Collapse
|
26
|
Choby JE, Skaar EP. Heme Synthesis and Acquisition in Bacterial Pathogens. J Mol Biol 2016; 428:3408-28. [PMID: 27019298 PMCID: PMC5125930 DOI: 10.1016/j.jmb.2016.03.018] [Citation(s) in RCA: 196] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/16/2016] [Accepted: 03/17/2016] [Indexed: 02/06/2023]
Abstract
Bacterial pathogens require the iron-containing cofactor heme to cause disease. Heme is essential to the function of hemoproteins, which are involved in energy generation by the electron transport chain, detoxification of host immune effectors, and other processes. During infection, bacterial pathogens must synthesize heme or acquire heme from the host; however, host heme is sequestered in high-affinity hemoproteins. Pathogens have evolved elaborate strategies to acquire heme from host sources, particularly hemoglobin, and both heme acquisition and synthesis are important for pathogenesis. Paradoxically, excess heme is toxic to bacteria and pathogens must rely on heme detoxification strategies. Heme is a key nutrient in the struggle for survival between host and pathogen, and its study has offered significant insight into the molecular mechanisms of bacterial pathogenesis.
Collapse
Affiliation(s)
- Jacob E Choby
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA; Tennessee Valley Healthcare System, U.S. Department of Veterans Affairs, Nashville, TN, USA.
| |
Collapse
|
27
|
Surdel MC, Dutter BF, Sulikowski GA, Skaar EP. Bacterial Nitric Oxide Synthase Is Required for the Staphylococcus aureus Response to Heme Stress. ACS Infect Dis 2016; 2:572-8. [PMID: 27626297 DOI: 10.1021/acsinfecdis.6b00081] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Staphylococcus aureus is a pathogen that causes significant morbidity and mortality worldwide. Within the vertebrate host, S. aureus requires heme as a nutrient iron source and as a cofactor for multiple cellular processes. Although required for pathogenesis, excess heme is toxic. S. aureus employs a two-component system, the heme sensor system (HssRS), to sense and protect against heme toxicity. Upon activation, HssRS induces the expression of the heme-regulated transporter (HrtAB), an efflux pump that alleviates heme toxicity. The ability to sense and respond to heme is critical for the pathogenesis of numerous Gram-positive organisms, yet the mechanism of heme sensing remains unknown. Compound '3981 was identified in a high-throughput screen as an activator of staphylococcal HssRS that triggers HssRS independently of heme accumulation. '3981 is toxic to S. aureus; however, derivatives of '3981 were synthesized that lack toxicity while retaining HssRS activation, enabling the interrogation of the heme stress response without confounding toxic effects of the parent molecule. Using '3981 derivatives as probes of the heme stress response, numerous genes required for '3981-induced activation of HssRS were uncovered. Specifically, multiple genes involved in the production of nitric oxide were identified, including the gene encoding bacterial nitric oxide synthase (bNOS). bNOS protects S. aureus from oxidative stress imposed by heme. Taken together, this work identifies bNOS as crucial for the S. aureus heme stress response, providing evidence that nitric oxide synthesis and heme sensing are intertwined.
Collapse
Affiliation(s)
- Matthew C. Surdel
- Department of Pathology, Microbiology,
and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Brendan F. Dutter
- Department of Chemistry, Vanderbilt Institute for Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Gary A. Sulikowski
- Department of Chemistry, Vanderbilt Institute for Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Eric P. Skaar
- Department of Pathology, Microbiology,
and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
- Tennessee
Valley Healthcare Systems, U.S. Department of Veterans Affairs, Nashville, Tennessee 37212, United States
| |
Collapse
|
28
|
Transcriptomic analysis for elucidating the physiological effects of 5-aminolevulinic acid accumulation on Corynebacterium glutamicum. Microbiol Res 2016; 192:292-299. [PMID: 27664748 DOI: 10.1016/j.micres.2016.08.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 07/10/2016] [Accepted: 08/03/2016] [Indexed: 11/22/2022]
Abstract
5-Aminolevulinic acid (ALA), the committed intermediate of the heme biosynthetic pathway, attracts close attention among researchers because of its potential applications to cancer treatment and agriculture. Overexpression of heterologous hemA and hemL, which encode glutamyl-tRNA reductase and glutamate-1-semialdehyde aminotransferase, respectively, in Corynebacterium glutamicum produces ALA, although whether ALA accumulation causes unintended effects on the host is unknown. Here we used an integrated systems approach to compare global transcriptional changes induced by the expression of hemA and hemL. Metabolic pathway such as glycolysis was inhibited, but tricarboxylic acid cycle, pentose phosphate pathway, and respiratory metabolism were stimulated. Moreover, the transcriptional levels of certain genes involved in heme biosynthesis were up-regulated, and the data implicate the two-component system (TCS) HrrSA was involved in the regulation of heme synthesis. With these understandings, it is proposed that ALA accumulation stimulates heme synthesis pathway and respiratory metabolism. Our study illuminates the physiological effects of overexpressing hemA and hemL on the phenotype of C. glutamicum and contributes important insights into the regulatory mechanisms of the heme biosynthetic pathways.
Collapse
|
29
|
Brannon JR, Hadjifrangiskou M. The arsenal of pathogens and antivirulence therapeutic strategies for disarming them. Drug Des Devel Ther 2016; 10:1795-806. [PMID: 27313446 PMCID: PMC4890686 DOI: 10.2147/dddt.s98939] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Pathogens deploy an arsenal of virulence factors (VFs) to establish themselves within their infectious niche. The discovery of antimicrobial compounds and their development into therapeutics has made a monumental impact on human and microbial populations. Although humans have used antimicrobials for medicinal and agricultural purposes, microorganism populations have developed and shared resistance mechanisms to persevere in the face of classical antimicrobials. However, a positive substitute is antivirulence therapy; antivirulence therapeutics prevent or interrupt an infection by counteracting a pathogen's VFs. Their application can reduce the use of broad-spectrum antimicrobials and dampen the frequency with which resistant strains emerge. Here, we summarize the contribution of VFs to various acute and chronic infections. In correspondence with this, we provide an overview of the research and development of antivirulence strategies.
Collapse
Affiliation(s)
- John R Brannon
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Maria Hadjifrangiskou
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
- Department of Urologic Surgery, Vanderbilt University School of Medicine, Nashville, TN, USA
| |
Collapse
|
30
|
Dutter BF, Mike LA, Reid PR, Chong KM, Ramos-Hunter SJ, Skaar EP, Sulikowski GA. Decoupling Activation of Heme Biosynthesis from Anaerobic Toxicity in a Molecule Active in Staphylococcus aureus. ACS Chem Biol 2016; 11:1354-61. [PMID: 26890615 DOI: 10.1021/acschembio.5b00934] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Small molecules active in the pathogenic bacterium Staphylococcus aureus are valuable tools for the study of its basic biology and pathogenesis, and many molecules may provide leads for novel therapeutics. We have previously reported a small molecule, 1, which activates endogenous heme biosynthesis in S. aureus, leading to an accumulation of intracellular heme. In addition to this novel activity, 1 also exhibits toxicity towards S. aureus growing under fermentative conditions. To determine if these activities are linked and establish what features of the molecule are required for activity, we synthesized a library of analogs around the structure of 1 and screened them for activation of heme biosynthesis and anaerobic toxicity to investigate structure-activity relationships. The results of this analysis suggest that these activities are not linked. Furthermore, we have identified the structural features that promote each activity and have established two classes of molecules: activators of heme biosynthesis and inhibitors of anaerobic growth. These molecules will serve as useful probes for their respective activities without concern for the off target effects of the parent compound.
Collapse
Affiliation(s)
| | | | | | - Katherine M. Chong
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Susan J. Ramos-Hunter
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37232, United States
| | | | - Gary A. Sulikowski
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37232, United States
| |
Collapse
|
31
|
Yu X, Jin H, Liu W, Wang Q, Qi Q. Engineering Corynebacterium glutamicum to produce 5-aminolevulinic acid from glucose. Microb Cell Fact 2015; 14:183. [PMID: 26577071 PMCID: PMC4650169 DOI: 10.1186/s12934-015-0364-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 10/20/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Corynebacterium glutamicum is generally regarded as a safe microorganism and is used to produce many biochemicals, including L-glutamate. 5-Aminolevulinic acid (ALA) is an L-glutamate derived non-protein amino acid, and is widely applied in fields such as medicine and agriculture. RESULTS The products of the gltX, hemA, and hemL genes participate in the synthesis of ALA from L-glutamate. Their annotated C. glutamicum homologs were shown to be functional using heterologous complementation and overexpression techniques. Coexpression of hemA and hemL in native host led to the accumulation of ALA, suggesting the potential of C. glutamicum to produce ALA for research and commercial purposes. To improve ALA production, we constructed recombinant C. glutamicum strains expressing hemA and hemL derived from different organisms. Transcriptome analysis indicated that the dissolved oxygen level and Fe(2+) concentration had major effects on ALA synthesis. The downstream pathway of heme biosynthesis was inhibited using small molecules or introducing genetic modifications. Small-scale flask cultures of engineered C. glutamicum produced 1.79 g/L of ALA. CONCLUSION Functional characterization of the key enzymes indicated complex regulation of the heme biosynthetic pathway in C. glutamicum. Systematic analysis and molecular genetic engineering of C. glutamicum may facilitate its development as a system for large-scale synthesis of ALA.
Collapse
Affiliation(s)
- Xiaoli Yu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, People's Republic of China.
| | - Haiying Jin
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, People's Republic of China.
| | - Wenjing Liu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, People's Republic of China.
| | - Qian Wang
- National Glycoengineering Research Center, Shandong University, Jinan, 250100, People's Republic of China.
| | - Qingsheng Qi
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, People's Republic of China.
| |
Collapse
|
32
|
Yu S, Zhang H, Yao D, Liu W, Wang X, Chen X, Wei Y, Zhang Z, Wang J, Yu L, Sun H, Wu Z, Yu Y, Song B, Ma J, Tong C, Cui Y. Identification of CD4+ T-cell epitopes on iron-regulated surface determinant B of Staphylococcus aureus. Microb Pathog 2015; 89:108-13. [PMID: 26423555 DOI: 10.1016/j.micpath.2015.09.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Accepted: 09/10/2015] [Indexed: 11/30/2022]
Abstract
Iron-regulated surface determinant B (IsdB) of Staphylococcus aureus (S. aureus) is a highly conserved surface protein that can induce protective CD4(+) T-cell immune response. A pivotal role of CD4(+) T-cells in effective immunity against S. aureus infection has been proved, but CD4(+) T-cell epitopes on the S. aureus IsdB have not been well identified. In this study, MHC binding assay was firstly used to predict CD4(+) T-cell epitopes on S. aureus IsdB protein, and six peptides were synthesized to validate the probable epitopes. Two novel IsdB CD4(+) T-cell epitopes, P1 (residues 159-178) and P4 (residues 287-306), were for the first time identified using CD4(+) T-cells obtained from IsdB-immunized C57BL/6 (H-2(b)) and BALB/c (H-2(d)) mice spleen based on cell proliferation and cytokines response. The results showed that P1 and P4 emulsified in Freund's adjuvant (FA) induced much higher cell proliferation compared with PBS emulsified in FA. CD4(+) T-cells stimulated with peptides P1 and P4 secreted significantly higher levels of IFN-γ and IL-17A. However, the level of the cytokine IL-4 almost remained unchanged, suggesting that P1 and P4 preferentially elicited polarized Th1-type responses. In addition, BALB/c mice just respond to P4 not P1, while C57BL/6 mice respond to P1 not P4, implying that epitope P1 and P4 were determined as H-2(b) and H-2(d) restricted epitope, respectively. Taken together, our data may provide an explanation of the IsdB-induced protection against S. aureus and highlight the possibility of developing the epitope-based vaccine against the S. aureus.
Collapse
Affiliation(s)
- Simiao Yu
- College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China
| | - Hua Zhang
- College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China
| | - Di Yao
- College of Animal Science and Veterinary Medicine, HeiLongJiang BaYi Agricultural University, Daqing 163319, China
| | - Wei Liu
- College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China
| | - Xintong Wang
- College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China
| | - Xiaoting Chen
- College of Animal Science and Veterinary Medicine, HeiLongJiang BaYi Agricultural University, Daqing 163319, China
| | - Yuhua Wei
- College of Animal Science and Veterinary Medicine, HeiLongJiang BaYi Agricultural University, Daqing 163319, China
| | - Zhenghai Zhang
- College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China
| | - Jiannan Wang
- College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China
| | - Liquan Yu
- College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China
| | - Hunan Sun
- College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China
| | - Zhijun Wu
- College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China
| | - Yongzhong Yu
- College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China
| | - Baifen Song
- College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China
| | - Jinzhu Ma
- College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China
| | - Chunyu Tong
- College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China
| | - Yudong Cui
- College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China; College of Animal Science and Veterinary Medicine, HeiLongJiang BaYi Agricultural University, Daqing 163319, China.
| |
Collapse
|
33
|
Hammer ND, Cassat JE, Noto MJ, Lojek LJ, Chadha AD, Schmitz JE, Creech CB, Skaar EP. Inter- and intraspecies metabolite exchange promotes virulence of antibiotic-resistant Staphylococcus aureus. Cell Host Microbe 2015; 16:531-7. [PMID: 25299336 DOI: 10.1016/j.chom.2014.09.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 08/04/2014] [Accepted: 08/26/2014] [Indexed: 02/08/2023]
Abstract
Adaptations that enable antimicrobial resistance often pose a fitness cost to the microorganism. Resistant pathogens must therefore overcome such fitness decreases to persist within their hosts. Here we demonstrate that the reduced fitness associated with one resistance-conferring mutation can be offset by community interactions with microorganisms harboring alternative mutations or via interactions with the human microbiota. Mutations that confer antibiotic resistance in the human pathogen Staphylococcus aureus led to decreased fitness, whereas coculture or coinfection of two distinct mutants resulted in collective recovery of fitness comparable to that of wild-type. Such fitness enhancements result from the exchange of metabolites between distinct mutants, leading to enhanced growth, virulence factor production, and pathogenicity. Interspecies fitness enhancements were also identified, as members of the human microbiota can promote growth of antibiotic-resistant S. aureus. Thus, inter- and intraspecies community interactions offset fitness costs and enable S. aureus to develop antibiotic resistance without loss of virulence.
Collapse
Affiliation(s)
- Neal D Hammer
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, 1161 21(st) Avenue South, Nashville, TN 37232, USA
| | - James E Cassat
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, 1161 21(st) Avenue South, Nashville, TN 37232, USA; Department of Pediatrics, Division of Pediatric Infectious Diseases, Vanderbilt University School of Medicine, 1161 21(st) Avenue South, Nashville, TN 37232, USA
| | - Michael J Noto
- Department of Medicine, Division of Allergy, Pulmonary, and Critical Care Medicine, Vanderbilt University School of Medicine, 1161 21(st) Avenue South Nashville, TN 37232, USA
| | - Lisa J Lojek
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, 1161 21(st) Avenue South, Nashville, TN 37232, USA
| | - Ashley D Chadha
- Department of Pediatrics, Division of Allergy, Immunology, and Pulmonary Medicine, Vanderbilt University School of Medicine, 1161 21(st) Avenue South, Nashville, TN 37232, USA
| | - Jonathan E Schmitz
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, 1161 21(st) Avenue South, Nashville, TN 37232, USA
| | - C Buddy Creech
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Vanderbilt University School of Medicine, 1161 21(st) Avenue South, Nashville, TN 37232, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, 1161 21(st) Avenue South, Nashville, TN 37232, USA.
| |
Collapse
|
34
|
Spraggins JM, Rizzo DG, Moore JL, Rose KL, Hammer ND, Skaar EP, Caprioli RM. MALDI FTICR IMS of Intact Proteins: Using Mass Accuracy to Link Protein Images with Proteomics Data. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:974-85. [PMID: 25904064 PMCID: PMC4442642 DOI: 10.1007/s13361-015-1147-5] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 03/20/2015] [Accepted: 03/20/2015] [Indexed: 05/11/2023]
Abstract
MALDI imaging mass spectrometry is a highly sensitive and selective tool used to visualize biomolecules in tissue. However, identification of detected proteins remains a difficult task. Indirect identification strategies have been limited by insufficient mass accuracy to confidently link ion images to proteomics data. Here, we demonstrate the capabilities of MALDI FTICR MS for imaging intact proteins. MALDI FTICR IMS provides an unprecedented combination of mass resolving power (~75,000 at m/z 5000) and accuracy (<5ppm) for proteins up to ~12kDa, enabling identification based on correlation with LC-MS/MS proteomics data. Analysis of rat brain tissue was performed as a proof-of-concept highlighting the capabilities of this approach by imaging and identifying a number of proteins including N-terminally acetylated thymosin β(4) (m/z 4,963.502, 0.6ppm) and ATP synthase subunit ε (m/z 5,636.074, -2.3ppm). MALDI FTICR IMS was also used to differentiate a series of oxidation products of S100A8 (m/z 10,164.03, -2.1ppm), a subunit of the heterodimer calprotectin, in kidney tissue from mice infected with Staphylococcus aureus. S100A8 - M37O/C42O(3) (m/z 10228.00, -2.6ppm) was found to co-localize with bacterial microcolonies at the center of infectious foci. The ability of MALDI FTICR IMS to distinguish S100A8 modifications is critical to understanding calprotectin's roll in nutritional immunity.
Collapse
Affiliation(s)
- Jeffrey M Spraggins
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37205, USA,
| | | | | | | | | | | | | |
Collapse
|
35
|
The Role of Two-Component Signal Transduction Systems in Staphylococcus aureus Virulence Regulation. Curr Top Microbiol Immunol 2015; 409:145-198. [PMID: 26728068 DOI: 10.1007/82_2015_5019] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Staphylococcus aureus is a versatile, opportunistic human pathogen that can asymptomatically colonize a human host but can also cause a variety of cutaneous and systemic infections. The ability of S. aureus to adapt to such diverse environments is reflected in the presence of complex regulatory networks fine-tuning metabolic and virulence gene expression. One of the most widely distributed mechanisms is the two-component signal transduction system (TCS) which allows a pathogen to alter its gene expression profile in response to environmental stimuli. The simpler TCSs consist of only a transmembrane histidine kinase (HK) and a cytosolic response regulator. S. aureus encodes a total of 16 conserved pairs of TCSs that are involved in diverse signalling cascades ranging from global virulence gene regulation (e.g. quorum sensing by the Agr system), the bacterial response to antimicrobial agents, cell wall metabolism, respiration and nutrient sensing. These regulatory circuits are often interconnected and affect each other's expression, thus fine-tuning staphylococcal gene regulation. This manuscript gives an overview of the current knowledge of staphylococcal environmental sensing by TCS and its influence on virulence gene expression and virulence itself. Understanding bacterial gene regulation by TCS can give major insights into staphylococcal pathogenicity and has important implications for knowledge-based drug design and vaccine formulation.
Collapse
|
36
|
Two-component system cross-regulation integrates Bacillus anthracis response to heme and cell envelope stress. PLoS Pathog 2014; 10:e1004044. [PMID: 24675902 PMCID: PMC3968170 DOI: 10.1371/journal.ppat.1004044] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 02/06/2014] [Indexed: 11/30/2022] Open
Abstract
Two-component signaling systems (TCSs) are one of the mechanisms that bacteria employ to sense and adapt to changes in the environment. A prototypical TCS functions as a phosphorelay from a membrane-bound sensor histidine kinase (HK) to a cytoplasmic response regulator (RR) that controls target gene expression. Despite significant homology in the signaling domains of HKs and RRs, TCSs are thought to typically function as linear systems with little to no cross-talk between non-cognate HK-RR pairs. Here we have identified several cell envelope acting compounds that stimulate a previously uncharacterized Bacillus anthracis TCS. Furthermore, this TCS cross-signals with the heme sensing TCS HssRS; therefore, we have named it HssRS interfacing TCS (HitRS). HssRS reciprocates cross-talk to HitRS, suggesting a link between heme toxicity and cell envelope stress. The signaling between HssRS and HitRS occurs in the parental B. anthracis strain; therefore, we classify HssRS-HitRS interactions as cross-regulation. Cross-talk between HssRS and HitRS occurs at both HK-RR and post-RR signaling junctions. Finally, HitRS also regulates a previously unstudied ABC transporter implicating this transporter in the response to cell envelope stress. This chemical biology approach to probing TCS signaling provides a new model for understanding how bacterial signaling networks are integrated to enable adaptation to complex environments such as those encountered during colonization of the vertebrate host. The vertebrate host is a hostile environment to microbes, where large variations in temperature, oxygen, and nutrient availability challenge microbial replication. In order to successfully infect vertebrates, pathogens must sense that they have entered their host and alter gene expression accordingly. One way bacteria adapt to their environment is by using two-component signaling systems (TCS), which are comprised of a signal sensor and a transcriptional regulator. The core signaling components of TCSs are conserved across the bacterial Kingdom; however, examples of interactions between two distinct TCS are extremely rare. Here we have probed how Bacillus anthracis, the causative agent of anthrax, adapts to life in the vertebrate host. The B. anthracis heme sensing TCS, HssRS, senses heme as a component of vertebrate blood and protects the bacteria from heme toxicity. We have identified a new TCS (HitRS), which is activated by compounds that alter the integrity of the cell envelope, and interacts with HssRS to coordinate a simultaneous response to both heme and cell envelope stress. This reciprocal HssRS-HitRS signaling is an unusual demonstration of bacterial signal cross-regulation and suggests that coordinating the response to heme and cell envelope stress is important for B. anthracis adaptation to the vertebrate host.
Collapse
|
37
|
Honsa ES, Johnson MDL, Rosch JW. The roles of transition metals in the physiology and pathogenesis of Streptococcus pneumoniae. Front Cell Infect Microbiol 2013; 3:92. [PMID: 24364001 PMCID: PMC3849628 DOI: 10.3389/fcimb.2013.00092] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 11/19/2013] [Indexed: 01/01/2023] Open
Abstract
For bacterial pathogens whose sole environmental reservoir is the human host, the acquisition of essential nutrients, particularly transition metals, is a critical aspect of survival due to tight sequestration and limitation strategies deployed to curtail pathogen outgrowth. As such, these bacteria have developed diverse, specialized acquisition mechanisms to obtain these metals from the niches of the body in which they reside. To oppose the spread of infection, the human host has evolved multiple mechanisms to counter bacterial invasion, including sequestering essential metals away from bacteria and exposing bacteria to lethal concentrations of metals. Hence, to maintain homeostasis within the host, pathogens must be able to acquire necessary metals from host proteins and to export such metals when concentrations become detrimental. Furthermore, this acquisition and efflux equilibrium must occur in a tissue-specific manner because the concentration of metals varies greatly within the various microenvironments of the human body. In this review, we examine the functional roles of the metal import and export systems of the Gram-positive pathogen Streptococcus pneumoniae in both signaling and pathogenesis.
Collapse
Affiliation(s)
- Erin S Honsa
- Department of Infectious Diseases, St. Jude Children's Research Hospital Memphis, TN, USA
| | - Michael D L Johnson
- Department of Infectious Diseases, St. Jude Children's Research Hospital Memphis, TN, USA
| | - Jason W Rosch
- Department of Infectious Diseases, St. Jude Children's Research Hospital Memphis, TN, USA
| |
Collapse
|
38
|
Hammer ND, Reniere ML, Cassat JE, Zhang Y, Hirsch AO, Indriati Hood M, Skaar EP. Two heme-dependent terminal oxidases power Staphylococcus aureus organ-specific colonization of the vertebrate host. mBio 2013; 4:e00241-13. [PMID: 23900169 PMCID: PMC3735196 DOI: 10.1128/mbio.00241-13] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 06/26/2013] [Indexed: 12/24/2022] Open
Abstract
UNLABELLED Staphylococcus aureus is a significant cause of infections worldwide and is able to utilize aerobic respiration, anaerobic respiration, or fermentation as the means by which it generates the energy needed for proliferation. Aerobic respiration is supported by heme-dependent terminal oxidases that catalyze the final step of aerobic respiration, the reduction of O2 to H2O. An inability to respire forces bacteria to generate energy via fermentation, resulting in reduced growth. Elucidating the roles of these energy-generating pathways during colonization of the host could uncover attractive therapeutic targets. Consistent with this idea, we report that inhibiting aerobic respiration by inactivating heme biosynthesis significantly impairs the ability of S. aureus to colonize the host. Two heme-dependent terminal oxidases support aerobic respiration of S. aureus, implying that the staphylococcal respiratory chain is branched. Systemic infection with S. aureus mutants limited to a single terminal oxidase results in an organ-specific colonization defect, resulting in reduced bacterial burdens in either the liver or the heart. Finally, inhibition of aerobic respiration can be achieved by exposing S. aureus to noniron heme analogues. These data provide evidence that aerobic respiration plays a major role in S. aureus colonization of the host and that this energy-generating process is a viable therapeutic target. IMPORTANCE Staphylococcus aureus poses a significant threat to public health as antibiotic-resistant isolates of this pathogen continue to emerge. Our understanding of the energy-generating processes that allow S. aureus to proliferate within the host is incomplete. Host-derived heme is the preferred source of nutrient iron during infection; however, S. aureus can synthesize heme de novo and use it to facilitate aerobic respiration. We demonstrate that S. aureus heme biosynthesis powers a branched aerobic respiratory chain composed of two terminal oxidases. The importance of having two terminal oxidases is demonstrated by the finding that each plays an essential role in colonizing distinct organs during systemic infection. Additionally, this process can be targeted by small-molecule heme analogues called noniron protoporphyrins. This study serves to demonstrate that heme biosynthesis supports two terminal oxidases that are required for aerobic respiration and are also essential for S. aureus pathogenesis.
Collapse
Affiliation(s)
- Neal D Hammer
- Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | | | | | | | | | | | | |
Collapse
|