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Akter S, Kamal E, Schwarz C, Lewin A. Gene knock-out in Mycobacterium abscessus using Streptococcus thermophilus CRISPR/Cas. J Microbiol Methods 2024; 220:106924. [PMID: 38548070 DOI: 10.1016/j.mimet.2024.106924] [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: 02/05/2024] [Revised: 03/25/2024] [Accepted: 03/25/2024] [Indexed: 04/02/2024]
Abstract
The CRISPRi system using dCas9Sth1 from Streptococcus thermophilus developed for Mycobacterium tuberculosis and M. smegmatis was modified to allow gene knock-out in M. abscessus. Efficacy of the knock-out system was evaluated by applying deletions and insertions to the mps1 gene. A comparative genomic analysis of mutants and wild type validated the target specificity.
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Affiliation(s)
- Suriya Akter
- Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch Institute, Berlin, Germany
| | - Elisabeth Kamal
- Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch Institute, Berlin, Germany.
| | - Carsten Schwarz
- Klinikum Westbrandenburg, Campus Potsdam, Cystic Fibrosis Section, Potsdam, Germany.
| | - Astrid Lewin
- Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch Institute, Berlin, Germany.
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2
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Boudehen YM, Tasrini Y, Aguilera-Correa JJ, Alcaraz M, Kremer L. Silencing essential gene expression in Mycobacterium abscessus during infection. Microbiol Spectr 2023; 11:e0283623. [PMID: 37831478 PMCID: PMC10714871 DOI: 10.1128/spectrum.02836-23] [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: 07/12/2023] [Accepted: 09/01/2023] [Indexed: 10/14/2023] Open
Abstract
IMPORTANCE Mycobacterium abscessus represents the most common rapidly growing mycobacterial pathogen in cystic fibrosis and is extremely difficult to eradicate. Essential genes are required for growth, often participate in pathogenesis, and encode valid drug targets for further chemotherapeutic developments. However, assessing the function of essential genes in M. abscessus remains challenging due to the limited spectrum of efficient genetic tools. Herein, we generated a Tet-OFF-based system allowing to knock down the expression of mmpL3, encoding the mycolic acid transporter in mycobacteria. Using this conditional mutant, we confirm the essentiality of mmpL3 in planktonic cultures, in biofilms, and during infection in zebrafish embryos. Thus, in this study, we developed a robust and reliable method to silence the expression of any M. abscessus gene during host infection.
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Affiliation(s)
- Yves-Marie Boudehen
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, Montpellier, France
| | - Yara Tasrini
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, Montpellier, France
| | - John Jairo Aguilera-Correa
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, Montpellier, France
| | - Matthéo Alcaraz
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, Montpellier, France
| | - Laurent Kremer
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, Montpellier, France
- INSERM, IRIM, Montpellier, France
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3
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Ng HF, Ngeow YF. Mutations in Genes Encoding 23S rRNA and FadD32 May be Associated with Linezolid Resistance in Mycobacteroides abscessus. Microb Drug Resist 2023; 29:41-46. [PMID: 36802272 DOI: 10.1089/mdr.2022.0068] [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: 02/23/2023] Open
Abstract
Linezolid is one of the antibiotics used to treat the Mycobacteroides abscessus infection. However, linezolid-resistance mechanisms of this organism are not well understood. The objective of this study was to identify possible linezolid-resistance determinants in M. abscessus through characterization of step-wise mutants selected from a linezolid-susceptible strain, M61 (minimum inhibitory concentration [MIC]: 0.25 mg/L). Whole-genome sequencing and subsequent PCR verification of the resistant second-step mutant, A2a(1) (MIC: >256 mg/L), revealed three mutations in its genome, two of which were found in the 23S rDNA (g2244t and g2788t) and another one was found in a gene encoding the fatty-acid-CoA ligase FadD32 (c880t→H294Y). The 23S rRNA is the molecular target of linezolid and mutations in this gene are likely to contribute to resistance. Furthermore, PCR analysis revealed that the c880t mutation in the fadD32 gene first appeared in the first-step mutant, A2 (MIC: 1 mg/L). Complementation of the wild-type M61 with the pMV261 plasmid carrying the mutant fadD32 gene caused the previously sensitive M61 to develop a reduced susceptibility to linezolid (MIC: 1 mg/L). The findings of this study uncovered hitherto undescribed mechanisms of linezolid resistance in M. abscessus that may be useful for the development of novel anti-infective agents against this multidrug-resistant pathogen.
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Affiliation(s)
- Hien Fuh Ng
- Dr. Wu Lien-Teh Centre for Research in Communicable Diseases, M. Kandiah Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, Selangor, Malaysia.,Department of Pre-clinical Sciences, M. Kandiah Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, Selangor, Malaysia
| | - Yun Fong Ngeow
- Dr. Wu Lien-Teh Centre for Research in Communicable Diseases, M. Kandiah Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, Selangor, Malaysia.,Department of Pre-clinical Sciences, M. Kandiah Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, Selangor, Malaysia
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4
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Bertram R, Neumann B, Schuster CF. Status quo of tet regulation in bacteria. Microb Biotechnol 2022; 15:1101-1119. [PMID: 34713957 PMCID: PMC8966031 DOI: 10.1111/1751-7915.13926] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/02/2021] [Accepted: 09/04/2021] [Indexed: 11/27/2022] Open
Abstract
The tetracycline repressor (TetR) belongs to the most popular, versatile and efficient transcriptional regulators used in bacterial genetics. In the tetracycline (Tc) resistance determinant tet(B) of transposon Tn10, tetR regulates the expression of a divergently oriented tetA gene that encodes a Tc antiporter. These components of Tn10 and of other natural or synthetic origins have been used for tetracycline-dependent gene regulation (tet regulation) in at least 40 bacterial genera. Tet regulation serves several purposes such as conditional complementation, depletion of essential genes, modulation of artificial genetic networks, protein overexpression or the control of gene expression within cell culture or animal infection models. Adaptations of the promoters employed have increased tet regulation efficiency and have made this system accessible to taxonomically distant bacteria. Variations of TetR, different effector molecules and mutated DNA binding sites have enabled new modes of gene expression control. This article provides a current overview of tet regulation in bacteria.
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Affiliation(s)
- Ralph Bertram
- Institute of Clinical Hygiene, Medical Microbiology and InfectiologyParacelsus Medical UniversityProf.‐Ernst‐Nathan‐Straße 1Nuremberg90419Germany
| | - Bernd Neumann
- Institute of Clinical Hygiene, Medical Microbiology and InfectiologyParacelsus Medical UniversityProf.‐Ernst‐Nathan‐Straße 1Nuremberg90419Germany
| | - Christopher F. Schuster
- Department of Infectious DiseasesDivision of Nosocomial Pathogens and Antibiotic ResistancesRobert Koch InstituteBurgstraße 37Wernigerode38855Germany
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5
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Boldrin F, Manganelli R. Repressible Promoter System to Study Essential Genes in Mycobacteria. Methods Mol Biol 2022; 2377:317-332. [PMID: 34709624 DOI: 10.1007/978-1-0716-1720-5_17] [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] [Indexed: 06/13/2023]
Abstract
Inducible gene expression systems represent powerful tools for studying essential gene function and for validation of drug targets in bacteria. Even if several regulated promoters have been characterized, only a few of them have been successfully used in Mycobacteria. Here we describe a successful mycobacterial gene regulation system based on the presence of two chromosomally encoded repressors: Pip and TetR, and a tunable promoter (Pptr) that allows a tight regulation of gene expression.
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Affiliation(s)
- Francesca Boldrin
- Department of Molecular Medicine, University of Padova, Padova, Italy
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6
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Genome-Wide Essentiality Analysis of Mycobacterium abscessus by Saturated Transposon Mutagenesis and Deep Sequencing. mBio 2021; 12:e0104921. [PMID: 34126767 PMCID: PMC8262987 DOI: 10.1128/mbio.01049-21] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Mycobacterium abscessus is an emerging opportunistic human pathogen that naturally resists most major classes of antibiotics, making infections difficult to treat. Thus far, little is known about M. abscessus physiology, pathogenesis, and drug resistance. Genome-wide analyses have comprehensively catalogued genes with essential functions in Mycobacterium tuberculosis and Mycobacterium avium subsp. hominissuis (here, M. avium) but not in M. abscessus. By optimizing transduction conditions, we achieved full saturation of TA insertion sites with Himar1 transposon mutagenesis in the M. abscessus ATCC 19977T genome, as confirmed by deep sequencing prior to essentiality analyses of annotated genes and other genomic features. The overall densities of inserted TA sites (85.7%), unoccupied TA sites (14.3%), and nonpermissive TA sites (8.1%) were similar to results in M. tuberculosis and M. avium. Of the 4,920 annotated genes, 326 were identified as essential, 269 (83%) of which have mutual homology with essential M. tuberculosis genes, while 39 (12%) are homologous to genes that are not essential in M. tuberculosis and M. avium, and 11 (3.4%) only have homologs in M. avium. Interestingly, 7 (2.1%) essential M. abscessus genes have no homologs in either M. tuberculosis or M. avium, two of which were found in phage-like elements. Most essential genes are involved in DNA replication, RNA transcription and translation, and posttranslational events to synthesize important macromolecules. Some essential genes may be involved in M. abscessus pathogenesis and antibiotics response, including certain essential tRNAs and new short open reading frames. Our findings will help to pave the way for better understanding of M. abscessus and benefit development of novel bactericidal drugs against M. abscessus. IMPORTANCE Limited knowledge regarding Mycobacterium abscessus pathogenesis and intrinsic resistance to most classes of antibiotics is a major obstacle to developing more effective strategies to prevent and mitigate disease. Using optimized procedures for Himar1 transposon mutagenesis and deep sequencing, we performed a comprehensive analysis to identify M. abscessus genetic elements essential for in vitro growth and compare them to similar data sets for M. tuberculosis and M. avium subsp. hominissuis. Most essential M. abscessus genes have mutual homology with essential M. tuberculosis genes, providing a foundation for leveraging available knowledge from M. tuberculosis to develop more effective drugs and other interventions against M. abscessus. A small number of essential genes unique to M. abscessus deserve further attention to gain insights into what makes M. abscessus different from other mycobacteria. The essential genes and other genomic features such as short open reading frames and noncoding RNA identified here will provide useful information for future study of M. abscessus pathogenicity and new drug development.
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7
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Le Moigne V, Bernut A, Cortès M, Viljoen A, Dupont C, Pawlik A, Gaillard JL, Misguich F, Crémazy F, Kremer L, Herrmann JL. Lsr2 Is an Important Determinant of Intracellular Growth and Virulence in Mycobacterium abscessus. Front Microbiol 2019; 10:905. [PMID: 31114557 PMCID: PMC6503116 DOI: 10.3389/fmicb.2019.00905] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 04/09/2019] [Indexed: 12/30/2022] Open
Abstract
Mycobacterium abscessus, a pathogen responsible for severe lung infections in cystic fibrosis patients, exhibits either smooth (S) or rough (R) morphotypes. The S-to-R transition correlates with inhibition of the synthesis and/or transport of glycopeptidolipids (GPLs) and is associated with an increase of pathogenicity in animal and human hosts. Lsr2 is a small nucleoid-associated protein highly conserved in mycobacteria, including M. abscessus, and is a functional homolog of the heat-stable nucleoid-structuring protein (H-NS). It is essential in Mycobacterium tuberculosis but not in the non-pathogenic model organism Mycobacterium smegmatis. It acts as a master transcriptional regulator of multiple genes involved in virulence and immunogenicity through binding to AT-rich genomic regions. Previous transcriptomic studies, confirmed here by quantitative PCR, showed increased expression of lsr2 (MAB_0545) in R morphotypes when compared to their S counterparts, suggesting a possible role of this protein in the virulence of the R form. This was addressed by generating lsr2 knock-out mutants in both S (Δlsr2-S) and R (Δlsr2-R) variants, demonstrating that this gene is dispensable for M. abscessus growth. We show that the wild-type S variant, Δlsr2-S and Δlsr2-R strains were more sensitive to H2O2 as compared to the wild-type R variant of M. abscessus. Importantly, virulence of the Lsr2 mutants was considerably diminished in cellular models (macrophage and amoeba) as well as in infected animals (mouse and zebrafish). Collectively, these results emphasize the importance of Lsr2 in M. abscessus virulence.
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Affiliation(s)
| | - Audrey Bernut
- UMR 9004, Centre National de la Recherche Scientifique, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, Montpellier, France
| | | | - Albertus Viljoen
- UMR 9004, Centre National de la Recherche Scientifique, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, Montpellier, France
| | - Christian Dupont
- UMR 9004, Centre National de la Recherche Scientifique, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, Montpellier, France
| | - Alexandre Pawlik
- Unité de Pathogénomique Mycobactérienne, Institut Pasteur, Paris, France
| | - Jean-Louis Gaillard
- 2I, UVSQ, INSERM, Université Paris-Saclay, Versailles, France.,APHP, GHU PIFO, Hôpital Raymond-Poincaré - Hôpital Ambroise-Paré, Boulogne-Billancourt, France
| | | | | | - Laurent Kremer
- UMR 9004, Centre National de la Recherche Scientifique, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, Montpellier, France.,INSERM, Institut de Recherche en Infectiologie de Montpellier, Montpellier, France
| | - Jean-Louis Herrmann
- 2I, UVSQ, INSERM, Université Paris-Saclay, Versailles, France.,APHP, GHU PIFO, Hôpital Raymond-Poincaré - Hôpital Ambroise-Paré, Boulogne-Billancourt, France
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8
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Richter A, Strauch A, Chao J, Ko M, Av-Gay Y. Screening of Preselected Libraries Targeting Mycobacterium abscessus for Drug Discovery. Antimicrob Agents Chemother 2018; 62:e00828-18. [PMID: 30012760 PMCID: PMC6125491 DOI: 10.1128/aac.00828-18] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/08/2018] [Indexed: 12/23/2022] Open
Abstract
Mycobacterium abscessus is intrinsically resistant to many antimycobacterial antibiotics, which presents serious problems in therapy. Here, we describe the development of a novel phenotype-based microscopic and computerized imaging drug screening approach. A pilot screen of 568 compounds from two libraries identified 17 hits. Eleven of these compounds are described for the first time as active against M. abscessus The impact of growth media on the activity of these compounds was tested, revealing that cation-adjusted Mueller-Hinton broth (MHII) supports better growth of actively replicating M. abscessus and improves the activity of associated compounds.
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Affiliation(s)
- Adrian Richter
- Division of Infectious Diseases, Department of Medicine, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Angelika Strauch
- Division of Infectious Diseases, Department of Medicine, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Joseph Chao
- Division of Infectious Diseases, Department of Medicine, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Mary Ko
- Division of Infectious Diseases, Department of Medicine, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Yossef Av-Gay
- Division of Infectious Diseases, Department of Medicine, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
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9
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Gutiérrez AV, Viljoen A, Ghigo E, Herrmann JL, Kremer L. Glycopeptidolipids, a Double-Edged Sword of the Mycobacterium abscessus Complex. Front Microbiol 2018; 9:1145. [PMID: 29922253 PMCID: PMC5996870 DOI: 10.3389/fmicb.2018.01145] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 05/14/2018] [Indexed: 01/14/2023] Open
Abstract
Mycobacterium abscessus is a rapidly-growing species causing a diverse panel of clinical manifestations, ranging from cutaneous infections to severe respiratory disease. Its unique cell wall, contributing largely to drug resistance and to pathogenicity, comprises a vast panoply of complex lipids, among which the glycopeptidolipids (GPLs) have been the focus of intense research. These lipids fulfill various important functions, from sliding motility or biofilm formation to interaction with host cells and intramacrophage trafficking. Being highly immunogenic, the induction of a strong humoral response is likely to select for rough low-GPL producers. These, in contrast to the smooth high-GPL producers, display aggregative properties, which strongly impacts upon intracellular survival. A propensity to grow as extracellular cords allows these low-GPL producing bacilli to escape the innate immune defenses. Transitioning from high-GPL to low-GPL producers implicates mutations within genes involved in biosynthesis or transport of GPL. This leads to induction of an intense pro-inflammatory response and robust and lethal infections in animal models, explaining the presence of rough isolates in patients with decreased pulmonary functions. Herein, we will discuss how, thanks to the generation of defined GPL mutants and the development of appropriate cellular and animal models to study pathogenesis, GPL contribute to M. abscessus biology and physiopathology.
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Affiliation(s)
- Ana Victoria Gutiérrez
- Centre National de la Recherche Scientifique, Institut de Recherche en Infectiologie de Montpellier, UMR 9004, Université de Montpellier, Montpellier, France.,CNRS, IRD 198, INSERM U1095, APHM, Institut Hospitalo-Universitaire Méditerranée Infection, UMR 7278, Aix-Marseille Université, Marseille, France
| | - Albertus Viljoen
- Centre National de la Recherche Scientifique, Institut de Recherche en Infectiologie de Montpellier, UMR 9004, Université de Montpellier, Montpellier, France
| | - Eric Ghigo
- CNRS, Campus Joseph Aiguier, Marseille, France
| | | | - Laurent Kremer
- Centre National de la Recherche Scientifique, Institut de Recherche en Infectiologie de Montpellier, UMR 9004, Université de Montpellier, Montpellier, France.,INSERM, IRIM, Montpellier, France
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10
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Viljoen A, Gutiérrez AV, Dupont C, Ghigo E, Kremer L. A Simple and Rapid Gene Disruption Strategy in Mycobacterium abscessus: On the Design and Application of Glycopeptidolipid Mutants. Front Cell Infect Microbiol 2018; 8:69. [PMID: 29594066 PMCID: PMC5861769 DOI: 10.3389/fcimb.2018.00069] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Accepted: 02/27/2018] [Indexed: 12/12/2022] Open
Abstract
Little is known about the disease-causing genetic determinants that are used by Mycobacterium abscessus, increasingly acknowledged as an important emerging pathogen, notably in cystic fibrosis. The presence or absence of surface exposed glycopeptidolipids (GPL) conditions the smooth (S) or rough (R) M. abscessus subsp. abscessus (M. abscessus) variants, respectively, which are characterized by distinct infective programs. However, only a handful of successful gene knock-out and conditional mutants have been reported in M. abscessus, testifying that genetic manipulation of this mycobacterium is difficult. To facilitate gene disruption and generation of conditional mutants in M. abscessus, we have designed a one-step single cross-over system that allows the rapid and simple generation of such mutants. Cloning of as small as 300 bp of the target gene allows for efficient homologous recombination to occur without additional exogenous recombination-promoting factors. The presence of tdTomato on the plasmids allows easily sifting out the large background of mutants spontaneously resistant to antibiotics. Using this strategy in the S genetic background and the target gene mmpL4a, necessary for GPL synthesis and transport, nearly 100% of red fluorescent clones exhibited a rough morphotype and lost GPL on the surface, suggesting that most red fluorescent colonies obtained after transformation incorporated the plasmid through homologous recombination into the chromosome. This system was further exploited to generate another strain with reduced GPL levels to explore how the presence of these cell wall-associated glycolipids influences M. abscessus hydrophobicity as well as virulence in the zebrafish model of infection. This mutant exhibited a more pronounced killing phenotype in zebrafish embryos compared to its S progenitor and this effect correlated with the production of abscesses in the central nervous system. Overall, these results suggest that the near-complete absence of GPL on the bacterial surface is a necessary condition for optimal pathogenesis of this mycobacterium. They also suggest that GPL content affects hydrophobicity of M. abscessus, potentially altering the aerosol transmission, which is of particular importance from an epidemiological and clinical perspective.
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Affiliation(s)
- Albertus Viljoen
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, Montpellier, France
| | - Ana Victoria Gutiérrez
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, Montpellier, France
- Unité de Recherche Microbes, Evolution, Phylogeny and Infection (MEPHI), Institut Hospitalier Universitaire Méditerranée-Infection, Marseille, France
| | - Christian Dupont
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, Montpellier, France
| | - Eric Ghigo
- Centre National de la Recherche Scientifique, Marseille, France
| | - Laurent Kremer
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, Montpellier, France
- IRIM, 34293, Institut National de la Santé et de la Recherche Médicale, Montpellier, France
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11
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Rominski A, Selchow P, Becker K, Brülle JK, Dal Molin M, Sander P. Elucidation of Mycobacterium abscessus aminoglycoside and capreomycin resistance by targeted deletion of three putative resistance genes. J Antimicrob Chemother 2018; 72:2191-2200. [PMID: 28486671 DOI: 10.1093/jac/dkx125] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 04/03/2017] [Indexed: 12/20/2022] Open
Abstract
Objectives Mycobacterium abscessus is innately resistant to a variety of drugs thereby limiting therapeutic options. Bacterial resistance to aminoglycosides (AGs) is conferred mainly by AG-modifying enzymes, which often have overlapping activities. Several putative AG-modifying enzymes are encoded in the genome of M. abscessus . The aim of this study was to investigate the molecular basis underlying AG resistance in M. abscessus . Methods M. abscessus deletion mutants deficient in one of three genes potentially involved in AG resistance, aac(2 ' ) , eis1 and eis2 , were generated by targeted gene inactivation, as were combinatorial double and triple deletion mutants. MICs were determined to study susceptibility to a variety of AG drugs and to capreomycin. Results Deletion of aac(2 ' ) increased susceptibility of M. abscessus to kanamycin B, tobramycin, dibekacin and gentamicin C. Deletion of eis2 increased susceptibility to capreomycin, hygromycin B, amikacin and kanamycin B. Deletion of eis1 did not affect drug susceptibility. Equally low MICs of apramycin, arbekacin, isepamicin and kanamycin A for WT and mutant strains indicate that these drugs are not inactivated by either AAC(2 ' ) or Eis enzymes. Conclusions M. abscessus expresses two distinct AG resistance determinants, AAC(2 ' ) and Eis2, which confer clinically relevant drug resistance.
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Affiliation(s)
- Anna Rominski
- Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 30/32, 8006 Zürich, Switzerland
| | - Petra Selchow
- Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 30/32, 8006 Zürich, Switzerland
| | - Katja Becker
- Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 30/32, 8006 Zürich, Switzerland
| | - Juliane K Brülle
- Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 30/32, 8006 Zürich, Switzerland
| | - Michael Dal Molin
- Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 30/32, 8006 Zürich, Switzerland
| | - Peter Sander
- Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 30/32, 8006 Zürich, Switzerland.,Nationales Zentrum für Mykobakterien, Gloriastrasse 30/32, 8006 Zürich, Switzerland
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12
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Dal Molin M, Gut M, Rominski A, Haldimann K, Becker K, Sander P. Molecular Mechanisms of Intrinsic Streptomycin Resistance in Mycobacterium abscessus. Antimicrob Agents Chemother 2018; 62:e01427-17. [PMID: 29061744 PMCID: PMC5740355 DOI: 10.1128/aac.01427-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/17/2017] [Indexed: 12/29/2022] Open
Abstract
Streptomycin, the first drug used for the treatment of tuberculosis, shows limited activity against the highly resistant pathogen Mycobacterium abscessus We recently identified two aminoglycoside-acetylating genes [aac(2') and eis2] which, however, do not affect susceptibility to streptomycin. This suggests the existence of a discrete mechanism of streptomycin resistance. M. abscessus BLASTP analysis identified MAB_2385 as a close homologue of the 3″-O-phosphotransferase [APH(3″)] from the opportunistic pathogen Mycobacterium fortuitum as a putative streptomycin resistance determinant. Heterologous expression of MAB_2385 in Mycobacterium smegmatis increased the streptomycin MIC, while the gene deletion mutant M. abscessus ΔMAB_2385 showed increased streptomycin susceptibility. The MICs of other aminoglycosides were not altered in M. abscessus ΔMAB_2385. This demonstrates that MAB_2385 encodes a specific and prime innate streptomycin resistance determinant in M. abscessus We further explored the feasibility of applying rpsL-based streptomycin counterselection to generate gene deletion mutants in M. abscessus Spontaneous streptomycin-resistant mutants of M. abscessus ΔMAB_2385 were selected, and we demonstrated that the wild-type rpsL is dominant over the mutated rpsLK43R in merodiploid strains. In a proof of concept study, we exploited this phenotype for construction of a targeted deletion mutant, thereby establishing an rpsL-based counterselection method in M. abscessus.
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Affiliation(s)
- Michael Dal Molin
- Institut für Medizinische Mikrobiologie, Universität Zürich, Zürich, Switzerland
| | - Myriam Gut
- Institut für Medizinische Mikrobiologie, Universität Zürich, Zürich, Switzerland
| | - Anna Rominski
- Institut für Medizinische Mikrobiologie, Universität Zürich, Zürich, Switzerland
| | - Klara Haldimann
- Institut für Medizinische Mikrobiologie, Universität Zürich, Zürich, Switzerland
| | - Katja Becker
- Institut für Medizinische Mikrobiologie, Universität Zürich, Zürich, Switzerland
| | - Peter Sander
- Institut für Medizinische Mikrobiologie, Universität Zürich, Zürich, Switzerland
- Nationales Zentrum für Mykobakterien, Zürich, Switzerland
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13
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Boldrin F, Degiacomi G, Serafini A, Kolly GS, Ventura M, Sala C, Provvedi R, Palù G, Cole ST, Manganelli R. Promoter mutagenesis for fine-tuning expression of essential genes in Mycobacterium tuberculosis. Microb Biotechnol 2017; 11:238-247. [PMID: 29076636 PMCID: PMC5743821 DOI: 10.1111/1751-7915.12875] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 09/05/2017] [Accepted: 09/25/2017] [Indexed: 02/04/2023] Open
Abstract
A range of regulated gene expression systems has been developed for mycobacteria in the last few years to facilitate the study of essential genes, validate novel drug targets and evaluate their vulnerability. Among these, the TetR/Pip-OFF repressible promoter system was successfully used in several mycobacterial species both in vitro and in vivo. In the first version of the system, the repressible promoter was Pptr , a strong Pip-repressible promoter of Streptomyces pristinaespiralis, which might hamper effective downregulation of genes with a low basal expression level. Here, we report an enhanced system that allows more effective control of genes expressed at low level. To this end, we subjected Pptr to targeted mutagenesis and produced 16 different promoters with different strength. Three of them, weaker than the wild-type promoter, were selected and characterized showing that they can indeed improve the performances of TetR/Pip-OFF repressible system both in vitro and in vivo increasing its stringency. Finally, we used these promoters to construct a series of bacterial biosensors with different sensitivity to DprE1 inhibitors and developed a whole-cell screening assay to identify inhibitors of this enzyme.
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Affiliation(s)
- Francesca Boldrin
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | - Giulia Degiacomi
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | - Agnese Serafini
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | - Gaëlle S Kolly
- Ecole Polytechnique Fédérale de Lausanne, Global Health Institute, Station 19, 1015, Lausanne, Switzerland
| | - Marcello Ventura
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | - Claudia Sala
- Ecole Polytechnique Fédérale de Lausanne, Global Health Institute, Station 19, 1015, Lausanne, Switzerland
| | - Roberta Provvedi
- Department of Biology, University of Padova, 35121, Padova, Italy
| | - Giorgio Palù
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | - Stewart T Cole
- Ecole Polytechnique Fédérale de Lausanne, Global Health Institute, Station 19, 1015, Lausanne, Switzerland
| | - Riccardo Manganelli
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
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14
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Le NH, Molle V, Eynard N, Miras M, Stella A, Bardou F, Galandrin S, Guillet V, André-Leroux G, Bellinzoni M, Alzari P, Mourey L, Burlet-Schiltz O, Daffé M, Marrakchi H. Ser/Thr Phosphorylation Regulates the Fatty Acyl-AMP Ligase Activity of FadD32, an Essential Enzyme in Mycolic Acid Biosynthesis. J Biol Chem 2016; 291:22793-22805. [PMID: 27590338 DOI: 10.1074/jbc.m116.748053] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 08/31/2016] [Indexed: 12/21/2022] Open
Abstract
Mycolic acids are essential components of the mycobacterial cell envelope, and their biosynthetic pathway is a well known source of antituberculous drug targets. Among the promising new targets in the pathway, FadD32 is an essential enzyme required for the activation of the long meromycolic chain of mycolic acids and is essential for mycobacterial growth. Following the in-depth biochemical, biophysical, and structural characterization of FadD32, we investigated its putative regulation via post-translational modifications. Comparison of the fatty acyl-AMP ligase activity between phosphorylated and dephosphorylated FadD32 isoforms showed that the native protein is phosphorylated by serine/threonine protein kinases and that this phosphorylation induced a significant loss of activity. Mass spectrometry analysis of the native protein confirmed the post-translational modifications and identified Thr-552 as the phosphosite. Phosphoablative and phosphomimetic FadD32 mutant proteins confirmed both the position and the importance of the modification and its correlation with the negative regulation of FadD32 activity. Investigation of the mycolic acid condensation reaction catalyzed by Pks13, involving FadD32 as a partner, showed that FadD32 phosphorylation also impacts the condensation activity. Altogether, our results bring to light FadD32 phosphorylation by serine/threonine protein kinases and its correlation with the enzyme-negative regulation, thus shedding a new horizon on the mycolic acid biosynthesis modulation and possible inhibition strategies for this promising drug target.
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Affiliation(s)
- Nguyen-Hung Le
- From the Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS
| | - Virginie Molle
- the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS UMR 5235, Place Eugène Bataillon, 34095 Montpellier Cedex 05, and
| | - Nathalie Eynard
- From the Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS
| | - Mathieu Miras
- From the Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS
| | - Alexandre Stella
- From the Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS
| | - Fabienne Bardou
- From the Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS
| | - Ségolène Galandrin
- From the Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS
| | - Valérie Guillet
- From the Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS
| | - Gwenaëlle André-Leroux
- the Institut Pasteur, Unité de Microbiologie Structurale, 25 Rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Marco Bellinzoni
- the Institut Pasteur, Unité de Microbiologie Structurale, 25 Rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Pedro Alzari
- the Institut Pasteur, Unité de Microbiologie Structurale, 25 Rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Lionel Mourey
- From the Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS
| | - Odile Burlet-Schiltz
- From the Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS
| | - Mamadou Daffé
- From the Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS,
| | - Hedia Marrakchi
- From the Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS,
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15
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In vivo assessment of drug efficacy against Mycobacterium abscessus using the embryonic zebrafish test system. Antimicrob Agents Chemother 2014; 58:4054-63. [PMID: 24798271 DOI: 10.1128/aac.00142-14] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycobacterium abscessus is responsible for a wide spectrum of clinical syndromes and is one of the most intrinsically drug-resistant mycobacterial species. Recent evaluation of the in vivo therapeutic efficacy of the few potentially active antibiotics against M. abscessus was essentially performed using immunocompromised mice. Herein, we assessed the feasibility and sensitivity of fluorescence imaging for monitoring the in vivo activity of drugs against acute M. abscessus infection using zebrafish embryos. A protocol was developed where clarithromycin and imipenem were directly added to water containing fluorescent M. abscessus-infected embryos in a 96-well plate format. The status of the infection with increasing drug concentrations was visualized on a spatiotemporal level. Drug efficacy was assessed quantitatively by measuring the index of protection, the bacterial burden (CFU), and the number of abscesses through fluorescence measurements. Both drugs were active in infected embryos and were capable of significantly increasing embryo survival in a dose-dependent manner. Protection from bacterial killing correlated with restricted mycobacterial growth in the drug-treated larvae and with reduced pathophysiological symptoms, such as the number of abscesses within the brain. In conclusion, we present here a new and efficient method for testing and compare the in vivo activity of two clinically relevant drugs based on a fluorescent reporter strain in zebrafish embryos. This approach could be used for rapid determination of the in vivo drug susceptibility profile of clinical isolates and to assess the preclinical efficacy of new compounds against M. abscessus.
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16
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Calado Nogueira de Moura V, Gibbs S, Jackson M. Gene replacement in Mycobacterium chelonae: application to the construction of porin knock-out mutants. PLoS One 2014; 9:e94951. [PMID: 24739882 PMCID: PMC3989263 DOI: 10.1371/journal.pone.0094951] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 03/21/2014] [Indexed: 01/06/2023] Open
Abstract
Mycobacterium chelonae is a rapidly growing mycobacterial opportunistic pathogen closely related to Mycobacterium abscessus that causes cornea, skin and soft tissue infections in humans. Although M. chelonae and the emerging mycobacterial pathogen M. abscessus have long been considered to belong to the same species, these two microorganisms considerably differ in terms of optimum growth temperature, drug susceptibility, pathogenicity and the types of infection they cause. The whole genome sequencing of clinical isolates of M. chelonae and M. abscessus is opening the way to comparative studies aimed at understanding the biology of these pathogens and elucidating the molecular bases of their pathogenicity and biocide resistance. Key to the validation of the numerous hypotheses that this approach will raise, however, is the availability of genetic tools allowing for the expression and targeted mutagenesis of genes in these species. While homologous recombination systems have recently been described for M. abscessus, genetic tools are lacking for M. chelonae. We here show that two different allelic replacement methods, one based on mycobacteriophage-encoded recombinases and the other on a temperature-sensitive plasmid harboring the counterselectable marker sacB, can be used to efficiently disrupt genes in this species. Knock-out mutants for each of the three porin genes of M. chelonae ATCC 35752 were constructed using both methodologies, one of which displays a significantly reduced glucose uptake rate consistent with decreased porin expression.
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Affiliation(s)
- Vinicius Calado Nogueira de Moura
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Sara Gibbs
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
- * E-mail:
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17
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Mycobacterium abscessus cording prevents phagocytosis and promotes abscess formation. Proc Natl Acad Sci U S A 2014; 111:E943-52. [PMID: 24567393 DOI: 10.1073/pnas.1321390111] [Citation(s) in RCA: 235] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mycobacterium abscessus is a rapidly growing Mycobacterium causing a wide spectrum of clinical syndromes. It now is recognized as a pulmonary pathogen to which cystic fibrosis patients have a particular susceptibility. The M. abscessus rough (R) variant, devoid of cell-surface glycopeptidolipids (GPLs), causes more severe clinical disease than the smooth (S) variant, but the underlying mechanisms of R-variant virulence remain obscure. Exploiting the optical transparency of zebrafish embryos, we observed that the increased virulence of the M. abscessus R variant compared with the S variant correlated with the loss of GPL production. The virulence of the R variant involved the massive production of serpentine cords, absent during S-variant infection, and the cords initiated abscess formation leading to rapid larval death. Cording occurred within the vasculature and was highly pronounced in the central nervous system (CNS). It appears that M. abscessus is transported to the CNS within macrophages. The release of M. abscessus from apoptotic macrophages initiated the formation of cords that grew too large to be phagocytized by macrophages or neutrophils. This study is a description of the crucial role of cording in the in vivo physiopathology of M. abscessus infection and emphasizes cording as a mechanism of immune evasion.
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18
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Schnappinger D, Ehrt S. Regulated Expression Systems for Mycobacteria and Their Applications. Microbiol Spectr 2014; 2:03. [PMID: 25485177 PMCID: PMC4254785 DOI: 10.1128/microbiolspec.mgm2-0018-2013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Indexed: 11/20/2022] Open
Abstract
For bacterial model organisms like Escherichia coli and Bacillus subtilis genetic tools to experimentally manipulate the activity of individual genes existed for decades. But for genetically less tractable yet medically important bacteria such as M. tuberculosis such tools have rarely been available. More recently several groups developed genetic switches that function efficiently in M. tuberculosis and other mycobacteria. Together these systems utilize six different transcription factors, eight different regulated promoters, and three different regulatory principles. Here we describe their design features, review their main applications, and discuss advantages and disadvantages of regulating transcription, translation, or protein stability for controlling gene activities in bacteria.
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Affiliation(s)
- Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Medical College, and Program in Molecular Biology, Weill Graduate School of Medical Sciences of Cornell University, New York, NY 10065
| | - Sabine Ehrt
- Department of Microbiology and Immunology, Weill Medical College, and Program in Immunology and Microbial Pathogenesis, Weill Graduate School of Medical Sciences of Cornell University, New York, NY 10065
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19
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Drosophila melanogaster model for Mycobacterium abscessus infection. Microbes Infect 2013; 15:788-95. [PMID: 23831804 DOI: 10.1016/j.micinf.2013.06.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 06/25/2013] [Accepted: 06/26/2013] [Indexed: 01/25/2023]
Abstract
Mycobacterium abscessus is a human pathogen that is responsible for a broad spectrum of tissue infections and disseminated infections in immunodeficient patients. This pathogen is one of the most resistant organisms to chemotherapeutic agents. Therefore, we tested the hypothesis that the fruit fly, Drosophila melanogaster, is a genetically tractable model host for M. abscessus. In this context, we infected D. melanogaster with M. abscessus. This M. abscessus infection results in dissemination in the fly body, followed by death, which is accompanied by severe indirect flight muscle and brain damage. Our data show that M. abscessus can grow and replicate in D. melanogaster w(1118) and that it elicited a humoral immune response, especially of the Toll antimicrobial peptide pathway. To the best of our knowledge, this is the first report that mycobacteria induce the production of antimicrobial peptides in D. melanogaster.
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20
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Galandrin S, Guillet V, Rane RS, Léger M, Radha N., Eynard N, Das K, Balganesh TS, Mourey L, Daffé M, Marrakchi H. Assay Development for Identifying Inhibitors of the Mycobacterial FadD32 Activity. ACTA ACUST UNITED AC 2013; 18:576-87. [DOI: 10.1177/1087057112474691] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
FadD32, a fatty acyl-AMP ligase (FAAL32) involved in the biosynthesis of mycolic acids, major and specific lipid components of the mycobacterial cell envelope, is essential for the survival of Mycobacterium tuberculosis, the causative agent of tuberculosis. The protein catalyzes the conversion of fatty acid to acyl-adenylate (acyl-AMP) in the presence of adenosine triphosphate and is conserved in all the mycobacterial species sequenced so far, thus representing a promising target for the development of novel antituberculous drugs. Here, we describe the optimization of the protein purification procedure and the development of a high-throughput screening assay for FadD32 activity. This spectrophotometric assay measuring the release of inorganic phosphate was optimized using the Mycobacterium smegmatis FadD32 as a surrogate enzyme. We describe the use of Tm (melting temperature) shift assay, which measures the modulation of FadD32 thermal stability, as a tool for the identification of potential ligands and for validation of compounds as inhibitors. Screening of a selected library of compounds led to the identification of five novel classes of inhibitors.
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Affiliation(s)
- Ségolène Galandrin
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Centre National de la Recherche Scientifique (CNRS), Département “Mécanismes Moléculaires des Infections Mycobactériennes,” Toulouse, France
- Université de Toulouse, Université Paul Sabatier, Toulouse, France
| | - Valérie Guillet
- IPBS, CNRS, Département “Biologie Structurale et Biophysique,” Toulouse, France
- Université de Toulouse, Université Paul Sabatier, Toulouse, France
| | - Rajendra S. Rane
- Distinguished Scientist, Council of Scientific and Industrial Research (CSIR), CSIR - Open Source Drug Discovery ( CSIR- OSDD ) Research Unit, Society for Innovation and Development, Indian Institute of Science, Bangalore, India
| | - Mathieu Léger
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Centre National de la Recherche Scientifique (CNRS), Département “Mécanismes Moléculaires des Infections Mycobactériennes,” Toulouse, France
- Université de Toulouse, Université Paul Sabatier, Toulouse, France
| | - Radha N.
- Distinguished Scientist, Council of Scientific and Industrial Research (CSIR), CSIR - Open Source Drug Discovery ( CSIR- OSDD ) Research Unit, Society for Innovation and Development, Indian Institute of Science, Bangalore, India
| | - Nathalie Eynard
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Centre National de la Recherche Scientifique (CNRS), Département “Mécanismes Moléculaires des Infections Mycobactériennes,” Toulouse, France
- Université de Toulouse, Université Paul Sabatier, Toulouse, France
| | - Kaveri Das
- Formerly with AstraZeneca, India; Currently: Independent Consultant, Bangalore, India
| | - Tanjore S. Balganesh
- Distinguished Scientist, Council of Scientific and Industrial Research (CSIR), CSIR - Open Source Drug Discovery ( CSIR- OSDD ) Research Unit, Society for Innovation and Development, Indian Institute of Science, Bangalore, India
| | - Lionel Mourey
- IPBS, CNRS, Département “Biologie Structurale et Biophysique,” Toulouse, France
- Université de Toulouse, Université Paul Sabatier, Toulouse, France
| | - Mamadou Daffé
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Centre National de la Recherche Scientifique (CNRS), Département “Mécanismes Moléculaires des Infections Mycobactériennes,” Toulouse, France
- Université de Toulouse, Université Paul Sabatier, Toulouse, France
| | - Hedia Marrakchi
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Centre National de la Recherche Scientifique (CNRS), Département “Mécanismes Moléculaires des Infections Mycobactériennes,” Toulouse, France
- Université de Toulouse, Université Paul Sabatier, Toulouse, France
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