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Fieweger RA, Wilburn KM, Montague CR, Roszkowski EK, Kelly CM, Southard TL, Sondermann H, Nazarova EV, VanderVen BC. MceG stabilizes the Mce1 and Mce4 transporters in Mycobacterium tuberculosis. J Biol Chem 2023; 299:102910. [PMID: 36642182 PMCID: PMC9947336 DOI: 10.1016/j.jbc.2023.102910] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 01/15/2023] Open
Abstract
Lipids are important nutrients for Mycobacterium tuberculosis (Mtb) to support bacterial survival in mammalian tissues and host cells. Fatty acids and cholesterol are imported across the Mtb cell wall via the dedicated Mce1 and Mce4 transporters, respectively. It is thought that the Mce1 and Mce4 transporters are comprised of subunits that confer substrate specificity and proteins that couple lipid transport to ATP hydrolysis, similar to other bacterial ABC transporters. However, unlike canonical bacterial ABC transporters, Mce1 and Mce4 appear to share a single ATPase, MceG. Previously, it was established that Mce1 and Mce4 are destabilized when key transporter subunits are rendered nonfunctional; therefore, we investigated here the role of MceG in Mce1 and Mce4 protein stability. We determined that key residues in the Walker B domain of MceG are required for the Mce1- and Mce4-mediated transport of fatty acids and cholesterol. Previously, it has been established that Mce1 and Mce4 are destabilized and/or degraded when key transporter subunits are rendered nonfunctional, thus we investigated a role for MceG in stabilizing Mce1 and Mce4. Using an unbiased quantitative proteomic approach, we demonstrate that Mce1 and Mce4 proteins are specifically degraded in mutants lacking MceG. Furthermore, bacteria expressing Walker B mutant variants of MceG failed to stabilize Mce1 and Mce4, and we show that deleting MceG impacts the fitness of Mtb in the lungs of mice. Thus, we conclude that MceG represents an enzymatic weakness that can be potentially leveraged to disable and destabilize both the Mce1 and Mce4 transporters in Mtb.
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Affiliation(s)
- Rachael A Fieweger
- Microbiology & Immunology, College of Veterinary Medicine, Cornell University, Ithaca New York, USA
| | - Kaley M Wilburn
- Microbiology & Immunology, College of Veterinary Medicine, Cornell University, Ithaca New York, USA
| | - Christine R Montague
- Microbiology & Immunology, College of Veterinary Medicine, Cornell University, Ithaca New York, USA
| | - Emma K Roszkowski
- Microbiology & Immunology, College of Veterinary Medicine, Cornell University, Ithaca New York, USA
| | - Carolyn M Kelly
- Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca New York, USA
| | - Teresa L Southard
- Biomedical Sciences; College of Veterinary Medicine, Cornell University, Ithaca New York, USA
| | - Holger Sondermann
- Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca New York, USA
| | - Evgeniya V Nazarova
- Microbiology & Immunology, College of Veterinary Medicine, Cornell University, Ithaca New York, USA
| | - Brian C VanderVen
- Microbiology & Immunology, College of Veterinary Medicine, Cornell University, Ithaca New York, USA.
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2
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Cyclic AMP-Mediated Inhibition of Cholesterol Catabolism in Mycobacterium tuberculosis by the Novel Drug Candidate GSK2556286. Antimicrob Agents Chemother 2023; 67:e0129422. [PMID: 36602336 PMCID: PMC9872607 DOI: 10.1128/aac.01294-22] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Despite the deployment of combination tuberculosis (TB) chemotherapy, efforts to identify shorter, nonrelapsing treatments have resulted in limited success. Recent evidence indicates that GSK2556286 (GSK286), which acts via Rv1625c, a membrane-bound adenylyl cyclase in Mycobacterium tuberculosis, shortens treatment in rodents relative to standard of care drugs. Moreover, GSK286 can replace linezolid in the three-drug, Nix-TB regimen. Given its therapeutic potential, we sought to better understand the mechanism of action of GSK286. The compound blocked growth of M. tuberculosis in cholesterol media and increased intracellular cAMP levels ~50-fold. GSK286 did not inhibit growth of an rv1625c transposon mutant in cholesterol media and did not induce cyclic AMP (cAMP) production in this mutant, suggesting that the compound acts on this adenylyl cyclase. GSK286 also induced cAMP production in Rhodococcus jostii RHA1, a cholesterol-catabolizing actinobacterium, when Rv1625c was heterologously expressed. However, these elevated levels of cAMP did not inhibit growth of R. jostii RHA1 in cholesterol medium. Mutations in rv1625c conferred cross-resistance to GSK286 and the known Rv1625c agonist, mCLB073. Metabolic profiling of M. tuberculosis cells revealed that elevated cAMP levels, induced using either an agonist or a genetic tool, did not significantly affect pools of steroid metabolites in cholesterol-incubated cells. Finally, the inhibitory effect of agonists was not dependent on the N-acetyltransferase MtPat. Together, these data establish that GSK286 is an Rv1625c agonist and sheds light on how cAMP signaling can be manipulated as a novel antibiotic strategy to shorten TB treatments. Nevertheless, the detailed mechanism of action of these compounds remains to be elucidated.
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Lemke C, Roach K, Ortega T, Tantillo DJ, Siegel JB, Peters RJ. Investigation of Acid–Base Catalysis in Halimadienyl Diphosphate Synthase Involved in Mycobacterium tuberculosis Virulence. ACS BIO & MED CHEM AU 2022; 2:490-498. [PMID: 36281298 PMCID: PMC9585517 DOI: 10.1021/acsbiomedchemau.2c00023] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
The devastating human
pathogenMycobacterium tuberculosis (Mtb)
is able to parasitize phagosomal compartments within alveolar
macrophage cells due, in part, to the activity of its cell-surface
lipids. Prominent among these is 1-tuberculosinyl-adenosine (1-TbAd),
a derivative of the diterpenoid tuberculosinyl (halima-5,13-dienyl)
diphosphate produced by the class II diterpene cyclase encoded by
Rv3377c, termed here MtHPS. Given the demonstrated ability of 1-TbAd
to act as a virulence factor for Mtb and the necessity for Rv3377c
for its production, there is significant interest in MtHPS activity.
Class II diterpene cyclases catalyze a general acid–base-mediated
carbocation cascade reaction initiated by protonation of the terminal
alkene in the general diterpenoid precursor (E,E,E)-geranylgeranyl diphosphate and terminated by deprotonation of the
final cyclized (and sometimes also rearranged) intermediate. Here,
structure-guided mutagenesis was applied to characterize the various
residues contributing to activation of the enzymatic acid, as well
as identify the enzymatic base in MtHPS. Particularly given the ability
of conservative substitution for the enzymatic base (Y479F) to generate
an alternative product (labda-7,13-dienyl diphosphate) via deprotonation
of an earlier unrearranged intermediate, further mutational analysis
was carried out to introduce potential alternative catalytic bases.
The results were combined with mechanistic molecular modeling to elucidate
how these mutations affect the catalytic activity of this important
enzyme. This not only provided detailed structure–function
insight into MtHPS but also further emphasized the inert nature of
the active site of MtHPS and class II diterpene cyclases more generally.
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Affiliation(s)
- Cody Lemke
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Kristin Roach
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Teresa Ortega
- Department of Chemistry, University of California-Davis, Davis, California 95616, United States
| | - Dean J. Tantillo
- Department of Chemistry, University of California-Davis, Davis, California 95616, United States
| | - Justin B. Siegel
- Department of Chemistry, University of California-Davis, Davis, California 95616, United States
- Department of Biochemistry and Molecular Medicine, University of California-Davis, Davis, California 95616, United States
- Genome Center, University of California-Davis, Davis, California 95616, United States
| | - Reuben J. Peters
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
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Kalra R, Tiwari D, Dkhar HK, Bhagyaraj E, Kumar R, Bhardwaj A, Gupta P. Host factors subverted by Mycobacterium tuberculosis: Potential targets for host directed therapy. Int Rev Immunol 2021; 42:43-70. [PMID: 34678117 DOI: 10.1080/08830185.2021.1990277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
INTRODUCTION Despite new approaches in the diagnosis and treatment of tuberculosis (TB), it continues to be a major health burden. Several immunotherapies that potentiate the immune response have come up as adjuncts to drug therapies against drug resistant TB strains; however, there needs to be an urgent appraisal of host specific drug targets for improving their clinical management and to curtail disease progression. Presently, various host directed therapies (HDTs) exist (repurposed drugs, nutraceuticals, monoclonal antibodies and immunomodulatory agents), but these mostly address molecules that combat disease progression. AREAS COVERED The current review discusses major Mycobacterium tuberculosis (M. tuberculosis) survival paradigms inside the host and presents a plethora of host targets subverted by M. tuberculosis which can be further explored for future HDTs. The host factors unique to M. tuberculosis infection (in humans) have also been identified through an in-silico interaction mapping. EXPERT OPINION HDTs could become the next-generation adjunct therapies in order to counter antimicrobial resistance and virulence, as well as to reduce the duration of existing TB treatments. However, current scientific efforts are largely directed toward combatants rather than host molecules co-opted by M. tuberculosis for its survival. This might drive the immune system to a hyper-inflammatory condition; therefore, we emphasize that host factors subverted by M. tuberculosis, and their subsequent neutralization, must be considered for development of better HDTs.
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Affiliation(s)
- Rashi Kalra
- Department of Molecular Biology, CSIR-Institute of Microbial Technology, Chandigarh-160036, India
| | - Drishti Tiwari
- Department of Molecular Biology, CSIR-Institute of Microbial Technology, Chandigarh-160036, India
| | - Hedwin Kitdorlang Dkhar
- Department of Molecular Biology, CSIR-Institute of Microbial Technology, Chandigarh-160036, India
| | - Ella Bhagyaraj
- Department of Molecular Biology, CSIR-Institute of Microbial Technology, Chandigarh-160036, India
| | - Rakesh Kumar
- Bioinformatics Center, CSIR-Institute of Microbial Technology, Chandigarh-160036, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Anshu Bhardwaj
- Bioinformatics Center, CSIR-Institute of Microbial Technology, Chandigarh-160036, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Pawan Gupta
- Department of Molecular Biology, CSIR-Institute of Microbial Technology, Chandigarh-160036, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
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5
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Antibacterial Natural Halimanes: Potential Source of Novel Antibiofilm Agents. Molecules 2020; 25:molecules25071707. [PMID: 32276434 PMCID: PMC7180734 DOI: 10.3390/molecules25071707] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/02/2020] [Accepted: 04/03/2020] [Indexed: 12/27/2022] Open
Abstract
The development of new agents against bacteria is an urgent necessity for human beings. The structured colony of bacterial cells, called the biofilm, is used to defend themselves from biocide attacks. For this reason, it is necessary to know their structures, develop new agents to eliminate them and to develop new procedures that allow an early diagnosis, by using biomarkers. Among natural products, some derivatives of diterpenes with halimane skeleton show antibacterial activity. Some halimanes have been isolated from marine organisms, structurally related with halimanes isolated from Mycobacterium tuberculosis. These halimanes are being evaluated as virulence factors and as tuberculosis biomarkers, this disease being one of the major causes of mortality and morbidity. In this work, the antibacterial halimanes will be reviewed, with their structural characteristics, activities, sources and the synthesis known until now.
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6
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Serafini A, Tan L, Horswell S, Howell S, Greenwood DJ, Hunt DM, Phan MD, Schembri M, Monteleone M, Montague CR, Britton W, Garza-Garcia A, Snijders AP, VanderVen B, Gutierrez MG, West NP, de Carvalho LPS. Mycobacterium tuberculosis requires glyoxylate shunt and reverse methylcitrate cycle for lactate and pyruvate metabolism. Mol Microbiol 2019; 112:1284-1307. [PMID: 31389636 PMCID: PMC6851703 DOI: 10.1111/mmi.14362] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Bacterial nutrition is an essential aspect of host–pathogen interaction. For the intracellular pathogen Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis in humans, fatty acids derived from lipid droplets are considered the major carbon source. However, many other soluble nutrients are available inside host cells and may be used as alternative carbon sources. Lactate and pyruvate are abundant in human cells and fluids, particularly during inflammation. In this work, we study Mtb metabolism of lactate and pyruvate combining classic microbial physiology with a ‘multi‐omics’ approach consisting of transposon‐directed insertion site sequencing (TraDIS), RNA‐seq transcriptomics, proteomics and stable isotopic labelling coupled with mass spectrometry‐based metabolomics. We discovered that Mtb is well adapted to use both lactate and pyruvate and that their metabolism requires gluconeogenesis, valine metabolism, the Krebs cycle, the GABA shunt, the glyoxylate shunt and the methylcitrate cycle. The last two pathways are traditionally associated with fatty acid metabolism and, unexpectedly, we found that in Mtb the methylcitrate cycle operates in reverse, to allow optimal metabolism of lactate and pyruvate. Our findings reveal a novel function for the methylcitrate cycle as a direct route for the biosynthesis of propionyl‐CoA, the essential precursor for the biosynthesis of the odd‐chain fatty acids.
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Affiliation(s)
- Agnese Serafini
- Mycobacterial Metabolism and Antibiotic Research Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Lendl Tan
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, 4072, Australia
| | - Stuart Horswell
- Bioinformatics and Biostatistics Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Steven Howell
- Mass Spectrometry Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Daniel J Greenwood
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Deborah M Hunt
- Mycobacterial Metabolism and Antibiotic Research Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Minh-Duy Phan
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, 4072, Australia
| | - Mark Schembri
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, 4072, Australia
| | - Mercedes Monteleone
- Mycobacterial Research Program, Centenary Institute of Cancer Medicine and Cell Biology, Camperdown, NSW, 2050, Australia
| | - Christine R Montague
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Warwick Britton
- Mycobacterial Research Program, Centenary Institute of Cancer Medicine and Cell Biology, Camperdown, NSW, 2050, Australia
| | - Acely Garza-Garcia
- Mycobacterial Metabolism and Antibiotic Research Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Ambrosius P Snijders
- Mass Spectrometry Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Brian VanderVen
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Maximiliano G Gutierrez
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Nicholas P West
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, 4072, Australia
| | - Luiz Pedro S de Carvalho
- Mycobacterial Metabolism and Antibiotic Research Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
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7
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Kohl K, Zangger H, Rossi M, Isorce N, Lye LF, Owens KL, Beverley SM, Mayer A, Fasel N. Importance of polyphosphate in the Leishmania life cycle. MICROBIAL CELL 2018; 5:371-384. [PMID: 30175107 PMCID: PMC6116282 DOI: 10.15698/mic2018.08.642] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Protozoan parasites contain negatively charged polymers of a few up to several hundreds of phosphate residues. In other organisms, these poly-phosphate (polyP) chains serve as an energy source and phosphate reservoir, and have been implicated in adaptation to stress and virulence of pathogenic organisms. In this study, we confirmed first that the polyP polymerase vacuolar transporter chaperone 4 (VTC4) is responsible for polyP synthesis in Leishmania parasites. During Leishmaniain vitro culture, polyP is accumulated in logarithmic growth phase and subsequently consumed once stationary phase is reached. However, polyP is not essential since VTC4-deficient (vtc4-) Leishmania proliferated normally in culture and differentiated into infective metacyclic parasites and into intracellular and axenic amastigotes. In in vivo mouse infections, L. majorVTC4 knockout showed a delay in lesion formation but ultimately gave rise to strong pathology, although we were unable to restore virulence by complementation to confirm this phenotype. Knockdown of VTC4 did not alter the course of L. guyanensis infections in mice, suggesting that polyP was not required for infection, or that very low levels of it suffice for lesion development. At higher temperatures, Leishmania promastigotes highly consumed polyP, and both knockdown or deletion of VTC4 diminished parasite survival. Thus, although polyP was not essential in the life cycle of the parasite, our data suggests a role for polyP in increasing parasite survival at higher temperatures, a situation faced by the parasite when transmitted to humans.
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Affiliation(s)
- Kid Kohl
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | - Haroun Zangger
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | - Matteo Rossi
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | - Nathalie Isorce
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | - Lon-Fye Lye
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Katherine L Owens
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Stephen M Beverley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Andreas Mayer
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | - Nicolas Fasel
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
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8
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Roncero AM, Tobal IE, Moro RF, Díez D, Marcos IS. Halimane diterpenoids: sources, structures, nomenclature and biological activities. Nat Prod Rep 2018; 35:955-991. [DOI: 10.1039/c8np00016f] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Diterpenes with a halimane skeleton constitute a small group of natural products that can be biogenetically considered as being between labdane and clerodane diterpenoids.
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Affiliation(s)
- Alejandro M. Roncero
- Departamento de Química Orgánica
- Facultad de Ciencias Químicas
- Universidad de Salamanca
- 37008 Salamanca
- Spain
| | - Ignacio E. Tobal
- Departamento de Química Orgánica
- Facultad de Ciencias Químicas
- Universidad de Salamanca
- 37008 Salamanca
- Spain
| | - Rosalina F. Moro
- Departamento de Química Orgánica
- Facultad de Ciencias Químicas
- Universidad de Salamanca
- 37008 Salamanca
- Spain
| | - David Díez
- Departamento de Química Orgánica
- Facultad de Ciencias Químicas
- Universidad de Salamanca
- 37008 Salamanca
- Spain
| | - Isidro S. Marcos
- Departamento de Química Orgánica
- Facultad de Ciencias Químicas
- Universidad de Salamanca
- 37008 Salamanca
- Spain
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9
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Magnesium uptake by connecting fluid-phase endocytosis to an intracellular inorganic cation filter. Nat Commun 2017; 8:1879. [PMID: 29192218 PMCID: PMC5709425 DOI: 10.1038/s41467-017-01930-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 10/24/2017] [Indexed: 12/03/2022] Open
Abstract
Cells acquire free metals through plasma membrane transporters. But, in natural settings, sequestering agents often render metals inaccessible to transporters, limiting metal bioavailability. Here we identify a pathway for metal acquisition, allowing cells to cope with this situation. Under limited bioavailability of Mg2+, yeast cells upregulate fluid-phase endocytosis and transfer solutes from the environment into their vacuole, an acidocalcisome-like compartment loaded with highly concentrated polyphosphate. We propose that this anionic inorganic polymer, which is an avid chelator of Mg2+, serves as an immobilized cation filter that accumulates Mg2+ inside these organelles. It thus allows the vacuolar exporter Mnr2 to efficiently transfer Mg2+ into the cytosol. Leishmania parasites also employ acidocalcisomal polyphosphate to multiply in their Mg2+-limited habitat, the phagolysosomes of inflammatory macrophages. This suggests that the pathway for metal uptake via endocytosis, acidocalcisomal polyphosphates and export into the cytosol, which we term EAPEC, is conserved. Metal bioavailability is frequently limited by sequestering agents which makes them inaccessible to cells. Here the authors show that cells can increase Mg2+ uptake via fluid phase endocytosis and accumulate this metal in their vacuole loaded with polyphosphate, and later can be exported to the cytosol.
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10
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Nazarova EV, Montague CR, La T, Wilburn KM, Sukumar N, Lee W, Caldwell S, Russell DG, VanderVen BC. Rv3723/LucA coordinates fatty acid and cholesterol uptake in Mycobacterium tuberculosis. eLife 2017; 6:e26969. [PMID: 28708968 PMCID: PMC5487216 DOI: 10.7554/elife.26969] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 06/07/2017] [Indexed: 01/05/2023] Open
Abstract
Pathogenic bacteria have evolved highly specialized systems to extract essential nutrients from their hosts. Mycobacterium tuberculosis (Mtb) scavenges lipids (cholesterol and fatty acids) to maintain infections in mammals but mechanisms and proteins responsible for the import of fatty acids in Mtb were previously unknown. Here, we identify and determine that the previously uncharacterized protein Rv3723/LucA, functions to integrate cholesterol and fatty acid uptake in Mtb. Rv3723/LucA interacts with subunits of the Mce1 and Mce4 complexes to coordinate the activities of these nutrient transporters by maintaining their stability. We also demonstrate that Mce1 functions as a fatty acid transporter in Mtb and determine that facilitating cholesterol and fatty acid import via Rv3723/LucA is required for full bacterial virulence in vivo. These data establish that fatty acid and cholesterol assimilation are inexorably linked in Mtb and reveals a key function for Rv3723/LucA in in coordinating thetransport of both these substrates.
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Affiliation(s)
- Evgeniya V Nazarova
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, United States
| | - Christine R Montague
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, United States
| | - Thuy La
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, United States
| | - Kaley M Wilburn
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, United States
| | - Neelima Sukumar
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, United States
| | - Wonsik Lee
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, United States
| | - Shannon Caldwell
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, United States
| | - David G Russell
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, United States
| | - Brian C VanderVen
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, United States
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11
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Wang J, Behr MA. Building a better bacillus: the emergence of Mycobacterium tuberculosis. Front Microbiol 2014; 5:139. [PMID: 24765091 PMCID: PMC3982062 DOI: 10.3389/fmicb.2014.00139] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 03/18/2014] [Indexed: 11/29/2022] Open
Abstract
The genus Mycobacterium is comprised of more than 150 species that reside in a wide variety of habitats. Most mycobacteria are environmental organisms that are either not associated with disease or are opportunistic pathogens that cause non-transmissible disease in immunocompromised individuals. In contrast, a small number of species, such as the tubercle bacillus, Mycobacterium tuberculosis, are host-adapted pathogens for which there is no known environmental reservoir. In recent years, gene disruption studies using the host-adapted pathogen have uncovered a number of “virulence factors,” yet genomic data indicate that many of these elements are present in non-pathogenic mycobacteria. This suggests that much of the genetic make-up that enables virulence in the host-adapted pathogen is already present in environmental members of the genus. In addition to these generic factors, we hypothesize that molecules elaborated exclusively by professional pathogens may be particularly implicated in the ability of M. tuberculosis to infect, persist, and cause transmissible pathology in its host species, Homo sapiens. One approach to identify these molecules is to employ comparative analysis of mycobacterial genomes, to define evolutionary events such as horizontal gene transfer (HGT) that contributed M. tuberculosis-specific genetic elements. Independent studies have now revealed the presence of HGT genes in the M. tuberculosis genome and their role in the pathogenesis of disease is the subject of ongoing investigations. Here we review these studies, focusing on the hypothesized role played by HGT loci in the emergence of M. tuberculosis from a related environmental species into a highly specialized human-adapted pathogen.
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Affiliation(s)
- Joyce Wang
- Department of Microbiology and Immunology, McGill University Montreal, QC, Canada
| | - Marcel A Behr
- Department of Microbiology and Immunology, McGill University Montreal, QC, Canada ; Department of Medicine, McGill University Montreal, QC, Canada ; McGill International TB Centre Montreal, QC, Canada
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12
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Bozzaro S, Buracco S, Peracino B. Iron metabolism and resistance to infection by invasive bacteria in the social amoeba Dictyostelium discoideum. Front Cell Infect Microbiol 2013; 3:50. [PMID: 24066281 PMCID: PMC3777012 DOI: 10.3389/fcimb.2013.00050] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 08/22/2013] [Indexed: 12/20/2022] Open
Abstract
Dictyostelium cells are forest soil amoebae, which feed on bacteria and proliferate as solitary cells until bacteria are consumed. Starvation triggers a change in life style, forcing cells to gather into aggregates to form multicellular organisms capable of cell differentiation and morphogenesis. As a soil amoeba and a phagocyte that grazes on bacteria as the obligate source of food, Dictyostelium could be a natural host of pathogenic bacteria. Indeed, many pathogens that occasionally infect humans are hosted for most of their time in protozoa or free-living amoebae, where evolution of their virulence traits occurs. Due to these features and its amenability to genetic manipulation, Dictyostelium has become a valuable model organism for studying strategies of both the host to resist infection and the pathogen to escape the defense mechanisms. Similarly to higher eukaryotes, iron homeostasis is crucial for Dictyostelium resistance to invasive bacteria. Iron is essential for Dictyostelium, as both iron deficiency or overload inhibit cell growth. The Dictyostelium genome shares with mammals many genes regulating iron homeostasis. Iron transporters of the Nramp (Slc11A) family are represented with two genes, encoding Nramp1 and Nramp2. Like the mammalian ortholog, Nramp1 is recruited to phagosomes and macropinosomes, whereas Nramp2 is a membrane protein of the contractile vacuole network, which regulates osmolarity. Nramp1 and Nramp2 localization in distinct compartments suggests that both proteins synergistically regulate iron homeostasis. Rather than by absorption via membrane transporters, iron is likely gained by degradation of ingested bacteria and efflux via Nramp1 from phagosomes to the cytosol. Nramp gene disruption increases Dictyostelium sensitivity to infection, enhancing intracellular growth of Legionella or Mycobacteria. Generation of mutants in other "iron genes" will help identify genes essential for iron homeostasis and resistance to pathogens.
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Affiliation(s)
- Salvatore Bozzaro
- Department of Clinical and Biological Sciences, University of Torino, Orbassano, Italy.
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Soldati T, Neyrolles O. Mycobacteria and the intraphagosomal environment: take it with a pinch of salt(s)! Traffic 2012; 13:1042-52. [PMID: 22462580 DOI: 10.1111/j.1600-0854.2012.01358.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 03/27/2012] [Accepted: 03/30/2012] [Indexed: 01/13/2023]
Abstract
Ancient protozoan phagocytes and modern professional phagocytes of metazoans, such as macrophages, employ evolutionarily conserved mechanisms to kill microbes. These mechanisms rely on microbial ingestion, followed by maturation of the phagocytic vacuole, or so-called phagosome. Phagosome maturation includes a series of fusion and fission events with the host cell endosomes and lysosomes, leading to a rapid increase of the degradative properties of the vacuole and to the destruction of the ingested microbe within a very hostile intracellular compartment, the phagolysosome. Historically, the mechanisms and weapons used by phagocytes to kill microbes have been separated into different classes. Phagosomal acidification, together with the production of reactive oxygen and nitrogen species, the selective manipulation of various ions in the phagosomal lumen, and finally the engagement of a battery of acidic hydrolases, are well-recognized players in this process. However, it is relatively recently that interconnections among these mechanisms have become apparent. In this review, we will focus on some emerging concepts about these interconnected aspects of the warfare at the host-pathogen interface, using mostly Mycobacterium tuberculosis as an example of intracellular pathogen. In particular, recent discoveries on the role of phagosomal ions and other chemicals in the control of pathogens, as well as mechanisms evolved by intracellular pathogens to circumvent or even exploit the weapons of the host cell will be discussed.
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Affiliation(s)
- Thierry Soldati
- Départment de Biochimie, Faculté des Sciences, Université de Genève, Sciences II, 30 quai Ernest Ansermet, CH-1211, Genève-4, Switzerland.
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Mann FM, Peters RJ. Isotuberculosinol: the unusual case of an immunomodulatory diterpenoid from Mycobacterium tuberculosis.. MEDCHEMCOMM 2012; 3:899-904. [PMID: 23926455 DOI: 10.1039/c2md20030a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Francis M Mann
- Department of Chemistry, Winona Sate University, Winona, MN 55987
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