1
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Roper NJ, Campbell ADG, Waddell PG, Brown AK, Ermanis K, Armstrong RJ. A stereodivergent multicomponent approach for the synthesis of C-N atropisomeric peptide analogues. Chem Sci 2024:d4sc04700a. [PMID: 39323517 PMCID: PMC11418089 DOI: 10.1039/d4sc04700a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2024] [Accepted: 09/15/2024] [Indexed: 09/27/2024] Open
Abstract
A four-component Ugi reaction is described for the stereoselective synthesis of novel C-N atropisomeric peptide analogues. Using this approach, a combination of simple, readily available starting materials (ortho-substituted anilines, aldehydes, carboxylic acids and isocyanides) could be combined to access complex products possessing both central and axial chirality in up to 92% yield and >95 : 5 d.r. Variation of the reaction temperature enabled the development of stereodivergent reactions capable of selectively targeting either diastereoisomer of a desired product from a single set of starting materials with high levels of stereocontrol. Detailed experimental and computational studies have been performed to probe the reaction mechanism and stereochemical outcome of these reactions. Preliminary studies show that novel atropisomeric scaffolds prepared using this method display inhibitory activity against M. tuberculosis with a significant difference in activity observed between different atropisomers.
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Affiliation(s)
- Natalie J Roper
- School of Natural and Environmental Sciences, Newcastle University Newcastle Upon Tyne NE1 7RU UK
| | - Aaron D G Campbell
- School of Natural and Environmental Sciences, Newcastle University Newcastle Upon Tyne NE1 7RU UK
| | - Paul G Waddell
- School of Natural and Environmental Sciences, Newcastle University Newcastle Upon Tyne NE1 7RU UK
| | - Alistair K Brown
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University Newcastle Upon Tyne NE2 4HH UK
| | - Kristaps Ermanis
- School of Chemistry, University of Nottingham, University Park Nottingham NG7 2RD UK
| | - Roly J Armstrong
- School of Natural and Environmental Sciences, Newcastle University Newcastle Upon Tyne NE1 7RU UK
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2
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Jeyasankar S, Kalapala YC, Sharma PR, Agarwal R. Antibacterial efficacy of mycobacteriophages against virulent Mycobacterium tuberculosis. BMC Microbiol 2024; 24:320. [PMID: 39227770 PMCID: PMC11373169 DOI: 10.1186/s12866-024-03474-3] [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: 07/15/2024] [Accepted: 08/23/2024] [Indexed: 09/05/2024] Open
Abstract
Tuberculosis (TB) remains a major global health concern, with drug-resistant strains posing a significant challenge to effective treatment. Bacteriophage (phage) therapy has emerged as a potential alternative to combat antibiotic resistance. In this study, we investigated the efficacy of widely used mycobacteriophages (D29, TM4, DS6A) against Mycobacterium tuberculosis (M. tuberculosis) under pathophysiological conditions associated with TB, such as low pH and hypoxia. We found that even at low multiplicity of infection (MOI), mycobacteriophages effectively infected M. tuberculosis, got rapidly amplified, and lysed M. tuberculosis, demonstrating their potential as therapeutic agents. Furthermore, we observed a novel phage tolerance mechanism with bacteria forming aggregates after several days of phage treatment. These aggregates were enriched with biofilm components and metabolically active bacteria. However, no phage tolerance was observed upon treatment with the three-phage mixture, highlighting the dynamic interplay between phages and bacteria and emphasizing the importance of phage cocktails. We also observed that phages were effective in lysing bacteria even under low pH and low oxygen concentrations as well as antibiotic-resistant bacteria. Our results provide key insights into phage infection of slow-growing bacteria and suggest that mycobacteriophages can effectively eliminate M. tuberculosis in complex pathophysiological environments like hypoxia and acidic pH. These results can aid in developing targeted phage-based therapies to combat antibiotic-resistant mycobacterial infections.
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Affiliation(s)
| | | | - Pallavi Raj Sharma
- Department of Bioengineering, Indian Institute of Science, Bengaluru, India
| | - Rachit Agarwal
- Department of Bioengineering, Indian Institute of Science, Bengaluru, India.
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3
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Johnson MP, Lauterkorn N, Lewis R, Labeed FH, Hingley-Wilson SM, Hughes MP. Dielectric properties of human macrophages are altered by Mycobacterium tuberculosis infection. Electrophoresis 2024; 45:1555-1561. [PMID: 38517249 DOI: 10.1002/elps.202300239] [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: 10/20/2023] [Revised: 03/06/2024] [Accepted: 03/08/2024] [Indexed: 03/23/2024]
Abstract
The analysis of cell electrophysiology for pathogenic samples at BSL3 can be problematic. It is virtually impossible to isolate infected from uninfected without a label, for example green fluorescent protein, which can potentially alter the cell electrical properties. Furthermore, the measurement of highly pathogenic organisms often requires equipment dedicated only for use with these organisms due to safety considerations. To address this, we have used dielectrophoresis to study the electrical properties of the human THP-1 cell line and monocyte-derived macrophages before and after infection with non-labelled Mycobacterium tuberculosis. Infection with these highly pathogenic bacilli resulted in changes including a raised surface conductance (associated with reduced zeta potential) and increased capacitance, suggesting an increase in surface roughness. We have also investigated the effect of fixation on THP-1 cells as a means to enable study on fixed samples in BSL1 or 2 laboratories, which suggests that the properties of these cells are largely unaffected by the fixation process. This advance results in a novel technique enabling the isolation of infected and non-infected cells in a sample without labelling.
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Affiliation(s)
- Matthew P Johnson
- Centre for Biomedical Engineering, University of Surrey, Guildford, Surrey, UK
| | - Nira Lauterkorn
- Department of Microbial Sciences, School of Biosciences, University of Surrey, Guildford, Surrey, UK
| | - Rebecca Lewis
- Department of Comparative Biomedical Sciences, University of Surrey, Guildford, Surrey, UK
| | - Fatima H Labeed
- Centre for Biomedical Engineering, University of Surrey, Guildford, Surrey, UK
- Department of Biology, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Suzanne M Hingley-Wilson
- Department of Microbial Sciences, School of Biosciences, University of Surrey, Guildford, Surrey, UK
| | - Michael Pycraft Hughes
- Centre for Biomedical Engineering, University of Surrey, Guildford, Surrey, UK
- Department of Biomedical Engineering and Biotechnology, Khalifa University, Abu Dhabi, United Arab Emirates
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4
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Mulholland CV, Wiggins TJ, Cui J, Vilchèze C, Rajagopalan S, Shultis MW, Reyes-Fernández EZ, Jacobs WR, Berney M. Propionate prevents loss of the PDIM virulence lipid in Mycobacterium tuberculosis. Nat Microbiol 2024; 9:1607-1618. [PMID: 38740932 PMCID: PMC11253637 DOI: 10.1038/s41564-024-01697-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 04/04/2024] [Indexed: 05/16/2024]
Abstract
Phthiocerol dimycocerosate (PDIM) is an essential virulence lipid of Mycobacterium tuberculosis. In vitro culturing rapidly selects for spontaneous PDIM-negative mutants that have attenuated virulence and increased cell wall permeability, thus impacting the relevance of experimental findings. PDIM loss can also reduce the efficacy of the BCG Pasteur vaccine. Here we show that vancomycin susceptibility can rapidly screen for M. tuberculosis PDIM production. We find that metabolic deficiency of methylmalonyl-CoA impedes the growth of PDIM-producing bacilli, selecting for PDIM-negative variants. Supplementation with odd-chain fatty acids, cholesterol or vitamin B12 restores PDIM-positive bacterial growth. Specifically, we show that propionate supplementation enhances PDIM-producing bacterial growth and selects against PDIM-negative mutants, analogous to in vivo conditions. Our study provides a simple approach to screen for and maintain PDIM production, and reveals how discrepancies between the host and in vitro nutrient environments can attenuate bacterial pathogenicity.
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Affiliation(s)
- Claire V Mulholland
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Thomas J Wiggins
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Jinhua Cui
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Catherine Vilchèze
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Saranathan Rajagopalan
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Michael W Shultis
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | | | - William R Jacobs
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Michael Berney
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA.
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5
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Singh M, Dhanwal A, Verma A, Augustin L, Kumari N, Chakraborti S, Agarwal N, Sriram D, Dey RJ. Discovery of potent antimycobacterial agents targeting lumazine synthase (RibH) of Mycobacterium tuberculosis. Sci Rep 2024; 14:12170. [PMID: 38806590 PMCID: PMC11133327 DOI: 10.1038/s41598-024-63051-6] [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: 07/28/2023] [Accepted: 05/24/2024] [Indexed: 05/30/2024] Open
Abstract
Tuberculosis (TB) continues to be a global health crisis, necessitating urgent interventions to address drug resistance and improve treatment efficacy. In this study, we validate lumazine synthase (RibH), a vital enzyme in the riboflavin biosynthetic pathway, as a potential drug target against Mycobacterium tuberculosis (M. tb) using a CRISPRi-based conditional gene knockdown strategy. We employ a high-throughput molecular docking approach to screen ~ 600,000 compounds targeting RibH. Through in vitro screening of 55 shortlisted compounds, we discover 3 compounds that exhibit potent antimycobacterial activity. These compounds also reduce intracellular burden of M. tb during macrophage infection and prevent the resuscitation of the nutrient-starved persister bacteria. Moreover, these three compounds enhance the bactericidal effect of first-line anti-TB drugs, isoniazid and rifampicin. Corroborating with the in silico predicted high docking scores along with favourable ADME and toxicity profiles, all three compounds demonstrate binding affinity towards purified lumazine synthase enzyme in vitro, in addition these compounds exhibit riboflavin displacement in an in vitro assay with purified lumazine synthase indicative of specificity of these compounds to the active site. Further, treatment of M. tb with these compounds indicate reduced production of flavin adenine dinucleotide (FAD), the ultimate end product of the riboflavin biosynthetic pathway suggesting the action of these drugs on riboflavin biosynthesis. These compounds also show acceptable safety profile in mammalian cells, with a high selective index. Hence, our study validates RibH as an important drug target against M. tb and identifies potent antimycobacterial agents.
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Affiliation(s)
- Monica Singh
- Department of Biological Sciences, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, Telangana, 500078, India
| | - Anannya Dhanwal
- Department of Biological Sciences, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, Telangana, 500078, India
| | - Arpita Verma
- Department of Biological Sciences, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, Telangana, 500078, India
| | - Linus Augustin
- Translational Health Science and Technology Institute, Faridabad, Haryana, 121001, India
| | - Niti Kumari
- National Institute of Animal Biotechnology (NIAB), Hyderabad, Telangana, 500032, India
| | - Soumyananda Chakraborti
- Department of Biological Sciences, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, Telangana, 500078, India
- National Institute of Malaria Research, Indian Council of Medical Research (ICMR), New Delhi, 110077, India
| | - Nisheeth Agarwal
- Translational Health Science and Technology Institute, Faridabad, Haryana, 121001, India
| | - Dharmarajan Sriram
- Department of Pharmacy, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, Telangana, 500078, India
| | - Ruchi Jain Dey
- Department of Biological Sciences, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, Telangana, 500078, India.
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6
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Ofori-Anyinam N, Hamblin M, Coldren ML, Li B, Mereddy G, Shaikh M, Shah A, Ranu N, Lu S, Blainey PC, Ma S, Collins JJ, Yang JH. KatG catalase deficiency confers bedaquiline hyper-susceptibility to isoniazid resistant Mycobacterium tuberculosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.17.562707. [PMID: 37905073 PMCID: PMC10614911 DOI: 10.1101/2023.10.17.562707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Multidrug-resistant tuberculosis (MDR-TB) is a growing source of global mortality and threatens global control of tuberculosis (TB) disease. The diarylquinoline bedaquiline (BDQ) recently emerged as a highly efficacious drug against MDR-TB, defined as resistance to the first-line drugs isoniazid (INH) and rifampin. INH resistance is primarily caused by loss-of-function mutations in the catalase KatG, but mechanisms underlying BDQ's efficacy against MDR-TB remain unknown. Here we employ a systems biology approach to investigate BDQ hyper-susceptibility in INH-resistant Mycobacterium tuberculosis . We found hyper-susceptibility to BDQ in INH-resistant cells is due to several physiological changes induced by KatG deficiency, including increased susceptibility to reactive oxygen species and DNA damage, remodeling of transcriptional programs, and metabolic repression of folate biosynthesis. We demonstrate BDQ hyper-susceptibility is common in INH-resistant clinical isolates. Collectively, these results highlight how altered bacterial physiology can impact drug efficacy in drug-resistant bacteria.
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7
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Mulholland CV, Wiggins TJ, Cui J, Vilchèze C, Rajagopalan S, Shultis MW, Reyes-Fernández EZ, Jacobs WR, Berney M. The PDIM paradox of Mycobacterium tuberculosis: new solutions to a persistent problem. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.16.562559. [PMID: 37905120 PMCID: PMC10614861 DOI: 10.1101/2023.10.16.562559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Phthiocerol dimycocerosate (PDIM) is an essential virulence lipid of Mycobacterium tuberculosis. In vitro culturing rapidly selects for spontaneous mutations that cause PDIM loss leading to virulence attenuation and increased cell wall permeability. We discovered that PDIM loss is due to a metabolic deficiency of methylmalonyl-CoA that impedes the growth of PDIM-producing bacilli. This can be remedied by supplementation with odd-chain fatty acids, cholesterol, or vitamin B12. We developed a much-needed facile and scalable routine assay for PDIM production and show that propionate supplementation enhances the growth of PDIM-producing bacilli and selects against PDIM-negative mutants, analogous to in vivo conditions. Our results solve a major issue in tuberculosis research and exemplify how discrepancies between the host and in vitro nutrient environments can attenuate bacterial pathogenicity.
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Affiliation(s)
- Claire V. Mulholland
- Department of Microbiology and Immunology, Albert Einstein College of Medicine,
Bronx, New York, USA
| | | | | | - Catherine Vilchèze
- Department of Microbiology and Immunology, Albert Einstein College of Medicine,
Bronx, New York, USA
| | - Saranathan Rajagopalan
- Department of Microbiology and Immunology, Albert Einstein College of Medicine,
Bronx, New York, USA
| | - Michael W. Shultis
- Department of Microbiology and Immunology, Albert Einstein College of Medicine,
Bronx, New York, USA
| | | | - William R. Jacobs
- Department of Microbiology and Immunology, Albert Einstein College of Medicine,
Bronx, New York, USA
| | - Michael Berney
- Department of Microbiology and Immunology, Albert Einstein College of Medicine,
Bronx, New York, USA
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8
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Pal P, Khan MY, Sharma S, Kumar Y, Mangla N, Kaushal PS, Agarwal N. ResR/McdR-regulated protein translation machinery contributes to drug resilience in Mycobacterium tuberculosis. Commun Biol 2023; 6:708. [PMID: 37433855 DOI: 10.1038/s42003-023-05059-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 06/21/2023] [Indexed: 07/13/2023] Open
Abstract
Survival response of the human tuberculosis pathogen, Mycobacterium tuberculosis (Mtb) to a diverse environmental cues is governed through its versatile transcription regulatory mechanisms with the help of a large pool of transcription regulators (TRs). Rv1830 is one such conserved TR, which remains uncharacterized in Mtb. It was named as McdR based on an effect on cell division upon its overexpression in Mycobacterium smegmatis. Recently, it has been implicated in antibiotic resilience in Mtb and reannotated as ResR. While Rv1830 affects cell division by modulating the expression of M. smegmatis whiB2, the underlying cause of its essentiality and regulation of drug resilience in Mtb is yet to be deciphered. Here we show that ResR/McdR, encoded by ERDMAN_2020 in virulent Mtb Erdman, is pivotal for bacterial proliferation and crucial metabolic activities. Importantly, ResR/McdR directly regulates ribosomal gene expression and protein synthesis, requiring distinct disordered N-terminal sequence. Compared to control, bacteria depleted with resR/mcdR exhibit delayed recovery post-antibiotic treatment. A similar effect upon knockdown of rplN operon genes further implicates ResR/McdR-regulated protein translation machinery in attributing drug resilience in Mtb. Overall, findings from this study suggest that chemical inhibitors of ResR/McdR may be proven effective as adjunctive therapy for shortening the duration of TB treatment.
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Affiliation(s)
- Pramila Pal
- Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, Haryana, India
- Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, Delhi, India
| | - Mohd Younus Khan
- Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, Haryana, India
- Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, Delhi, India
| | - Shivani Sharma
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, Haryana, India
| | - Yashwant Kumar
- Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, Haryana, India
| | - Nikita Mangla
- Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, Haryana, India
- Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, Delhi, India
| | - Prem S Kaushal
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, Haryana, India
| | - Nisheeth Agarwal
- Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, Haryana, India.
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9
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Opperman CJ, Wojno J, Goosen W, Warren R. Phages for the treatment of Mycobacterium species. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 201:41-92. [PMID: 37770176 DOI: 10.1016/bs.pmbts.2023.03.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Highly drug-resistant strains are not uncommon among the Mycobacterium genus, with patients requiring lengthy antibiotic treatment regimens with multiple drugs and harmful side effects. This alarming increase in antibiotic resistance globally has renewed the interest in mycobacteriophage therapy for both Mycobacterium tuberculosis complex and non-tuberculosis mycobacteria. With the increasing number of genetically well-characterized mycobacteriophages and robust engineering tools to convert temperate phages to obligate lytic phages, the phage cache against extensive drug-resistant mycobacteria is constantly expanding. Synergistic effects between phages and TB drugs are also a promising avenue to research, with mycobacteriophages having several additional advantages compared to traditional antibiotics due to their different modes of action. These advantages include less side effects, a narrow host spectrum, biofilm penetration, self-replication at the site of infection and the potential to be manufactured on a large scale. In addition, mycobacteriophage enzymes, not yet in clinical use, warrant further studies with their additional benefits for rupturing host bacteria thereby limiting resistance development as well as showing promise in vitro to act synergistically with TB drugs. Before mycobacteriophage therapy can be envisioned as part of routine care, several obstacles must be overcome to translate in vitro work into clinical practice. Strategies to target intracellular bacteria and selecting phage cocktails to limit cross-resistance remain important avenues to explore. However, insight into pathophysiological host-phage interactions on a molecular level and innovative solutions to transcend mycobacteriophage therapy impediments, offer sufficient encouragement to explore phage therapy. Recently, the first successful clinical studies were performed using a mycobacteriophage-constructed cocktail to treat non-tuberculosis mycobacteria, providing substantial insight into lessons learned and potential pitfalls to avoid in order to ensure favorable outcomes. However, due to mycobacterium strain variation, mycobacteriophage therapy remains personalized, only being utilized in compassionate care cases until there is further regulatory approval. Therefore, identifying the determinants that influence clinical outcomes that can expand the repertoire of mycobacteriophages for therapeutic benefit, remains key for their future application.
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Affiliation(s)
- Christoffel Johannes Opperman
- National Health Laboratory Service, Green Point TB-Laboratory, Cape Town, South Africa; DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, SAMRC Centre for tuberculosis Research, Division of Molecular Biology and Human Genetics, Stellenbosch University, Cape Town, South Africa; Division of Medical Microbiology, University of Cape Town, Cape Town, South Africa.
| | - Justyna Wojno
- Division of Medical Microbiology, University of Cape Town, Cape Town, South Africa; Lancet Laboratories, Cape Town, South Africa
| | - Wynand Goosen
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, SAMRC Centre for tuberculosis Research, Division of Molecular Biology and Human Genetics, Stellenbosch University, Cape Town, South Africa
| | - Rob Warren
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, SAMRC Centre for tuberculosis Research, Division of Molecular Biology and Human Genetics, Stellenbosch University, Cape Town, South Africa
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10
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Ju X, Li S, Froom R, Wang L, Lilic M, Campbell EA, Rock JM, Liu S. Incomplete transcripts dominate the Mycobacterium tuberculosis transcriptome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.10.532058. [PMID: 36945399 PMCID: PMC10028986 DOI: 10.1101/2023.03.10.532058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
Mycobacterium tuberculosis (Mtb) is a bacterial pathogen that causes tuberculosis, an infectious disease that inflicts major health and economic costs around the world 1 . Mtb encounters a diversity of environments during its lifecycle, and responds to these changing environments by reprogramming its transcriptional output 2 . However, the transcriptomic features of Mtb remain poorly characterized. In this work, we comprehensively profile the Mtb transcriptome using the SEnd-seq method that simultaneously captures the 5' and 3' ends of RNA 3 . Surprisingly, we find that the RNA coverage for most of the Mtb transcription units display a gradual drop-off within a 200-500 nucleotide window downstream of the transcription start site, yielding a massive number of incomplete transcripts with heterogeneous 3' ends. We further show that the accumulation of these short RNAs is mainly due to the intrinsically low processivity of the Mtb transcription machinery rather than trans-acting factors such as Rho. Finally, we demonstrate that transcription-translation coupling plays a critical role in generating full-length protein-coding transcripts in Mtb. In sum, our results depict a mycobacterial transcriptome that is dominated by incomplete RNA products, suggesting a distinctive set of transcriptional regulatory mechanisms that could be exploited for new therapeutics.
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11
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Ongwae GM, Lepori I, Chordia MD, Dalesandro BE, Apostolos AJ, Siegrist MS, Pires MM. Measurement of Small Molecule Accumulation into Diderm Bacteria. ACS Infect Dis 2023; 9:97-110. [PMID: 36530146 DOI: 10.1021/acsinfecdis.2c00435] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Some of the most dangerous bacterial pathogens (Gram-negative and mycobacterial) deploy a formidable secondary membrane barrier to reduce the influx of exogenous molecules. For Gram-negative bacteria, this second exterior membrane is known as the outer membrane (OM), while for the Gram-indeterminate Mycobacteria, it is known as the "myco" membrane. Although different in composition, both the OM and mycomembrane are key structures that restrict the passive permeation of small molecules into bacterial cells. Although it is well-appreciated that such structures are principal determinants of small molecule permeation, it has proven to be challenging to assess this feature in a robust and quantitative way or in complex, infection-relevant settings. Herein, we describe the development of the bacterial chloro-alkane penetration assay (BaCAPA), which employs the use of a genetically encoded protein called HaloTag, to measure the uptake and accumulation of molecules into model Gram-negative and mycobacterial species, Escherichia coli and Mycobacterium smegmatis, respectively, and into the human pathogen Mycobacterium tuberculosis. The HaloTag protein can be directed to either the cytoplasm or the periplasm of bacteria. This offers the possibility of compartmental analysis of permeation across individual cell membranes. Significantly, we also showed that BaCAPA can be used to analyze the permeation of molecules into host cell-internalized E. coli and M. tuberculosis, a critical capability for analyzing intracellular pathogens. Together, our results show that BaCAPA affords facile measurement of permeability across four barriers: the host plasma and phagosomal membranes and the diderm bacterial cell envelope.
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Affiliation(s)
- George M Ongwae
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Irene Lepori
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Mahendra D Chordia
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Brianna E Dalesandro
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Alexis J Apostolos
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - M Sloan Siegrist
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts 01003, United States.,Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Marcos M Pires
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
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12
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Pang AH, Green KD, Chandrika NT, Garzan A, Punetha A, Holbrook SYL, Willby MJ, Posey JE, Tsodikov OV, Garneau-Tsodikova S. Discovery of substituted benzyloxy-benzylamine inhibitors of acetyltransferase Eis and their anti-mycobacterial activity. Eur J Med Chem 2022; 242:114698. [PMID: 36037791 PMCID: PMC9481687 DOI: 10.1016/j.ejmech.2022.114698] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/09/2022] [Accepted: 08/15/2022] [Indexed: 11/30/2022]
Abstract
A clinically significant mechanism of tuberculosis resistance to the aminoglycoside kanamycin (KAN) is its acetylation catalyzed by upregulated Mycobacterium tuberculosis (Mtb) acetyltransferase Eis. In search for inhibitors of Eis, we discovered an inhibitor with a substituted benzyloxy-benzylamine scaffold. A structure-activity relationship study of 38 compounds in this structural family yielded highly potent (IC50 ∼ 1 μM) Eis inhibitors, which did not inhibit other acetyltransferases. Crystal structures of Eis in complexes with three of the inhibitors showed that the inhibitors were bound in the aminoglycoside binding site of Eis, consistent with the competitive mode of inhibition, as established by kinetics measurements. When tested in Mtb cultures, two inhibitors (47 and 55) completely abolished resistance to KAN of the highly KAN-resistant strain Mtb mc2 6230 K204, likely due to Eis inhibition as a major mechanism. Thirteen of the compounds were toxic even in the absence of KAN to Mtb and other mycobacteria, but not to non-mycobacteria or to mammalian cells. This, yet unidentified mechanism of toxicity, distinct from Eis inhibition, will merit future studies along with further development of these molecules as anti-mycobacterial agents.
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Affiliation(s)
- Allan H Pang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA
| | - Keith D Green
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA
| | - Nishad Thamban Chandrika
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA
| | - Atefeh Garzan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA
| | - Ankita Punetha
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA
| | - Selina Y L Holbrook
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA
| | - Melisa J Willby
- Laboratory Branch, Division of Tuberculosis Elimination, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - James E Posey
- Laboratory Branch, Division of Tuberculosis Elimination, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Oleg V Tsodikov
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA.
| | - Sylvie Garneau-Tsodikova
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA.
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13
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Akwani WC, van Vliet AH, Joel JO, Andres S, Diricks M, Maurer FP, Chambers MA, Hingley-Wilson SM. The Use of Comparative Genomic Analysis for the Development of Subspecies-Specific PCR Assays for Mycobacterium abscessus. Front Cell Infect Microbiol 2022; 12:816615. [PMID: 35419298 PMCID: PMC8995789 DOI: 10.3389/fcimb.2022.816615] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 03/07/2022] [Indexed: 01/21/2023] Open
Abstract
Mycobacterium abscessus complex (MABC) is an important pathogen of immunocompromised patients. Accurate and rapid determination of MABC at the subspecies level is vital for optimal antibiotic therapy. Here we have used comparative genomics to design MABC subspecies-specific PCR assays. Analysis of single nucleotide polymorphisms and core genome multilocus sequence typing showed clustering of genomes into three distinct clusters representing the MABC subspecies M. abscessus, M. bolletii and M. massiliense. Pangenome analysis of 318 MABC genomes from the three subspecies allowed for the identification of 15 MABC subspecies-specific genes. In silico testing of primer sets against 1,663 publicly available MABC genomes and 66 other closely related Mycobacterium genomes showed that all assays had >97% sensitivity and >98% specificity. Subsequent experimental validation of two subspecies-specific genes each showed the PCR assays worked well in individual and multiplex format with no false-positivity with 5 other mycobacteria of clinical importance. In conclusion, we have developed a rapid, accurate, multiplex PCR-assay for discriminating MABC subspecies that could improve their detection, diagnosis and inform correct treatment choice.
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Affiliation(s)
- Winifred C. Akwani
- Department of Microbial Sciences, School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Arnoud H.M. van Vliet
- Department of Pathology and Infectious Diseases, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Jordan O. Joel
- Department of Pathology and Infectious Diseases, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Sönke Andres
- National and Supranational Reference Center for Mycobacteria, Research Center Borstel, Borstel, Germany
| | - Margo Diricks
- National and Supranational Reference Center for Mycobacteria, Research Center Borstel, Borstel, Germany
- German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
- Molecular and Experimental Mycobacteriology, Research Center Borstel, Borstel, Germany
| | - Florian P. Maurer
- National and Supranational Reference Center for Mycobacteria, Research Center Borstel, Borstel, Germany
- Molecular and Experimental Mycobacteriology, Research Center Borstel, Borstel, Germany
- Institute of Medical Microbiology, Virology, and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Mark A. Chambers
- Department of Microbial Sciences, School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
- Department of Pathology and Infectious Diseases, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Suzanne M. Hingley-Wilson
- Department of Microbial Sciences, School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
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14
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Osman MM, Shanahan JK, Chu F, Takaki KK, Pinckert ML, Pagán AJ, Brosch R, Conrad WH, Ramakrishnan L. The C terminus of the mycobacterium ESX-1 secretion system substrate ESAT-6 is required for phagosomal membrane damage and virulence. Proc Natl Acad Sci U S A 2022; 119:e2122161119. [PMID: 35271388 PMCID: PMC8931374 DOI: 10.1073/pnas.2122161119] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 01/15/2022] [Indexed: 12/21/2022] Open
Abstract
SignificanceTuberculosis (TB), an ancient disease of humanity, continues to be a major cause of worldwide death. The causative agent of TB, Mycobacterium tuberculosis, and its close pathogenic relative Mycobacterium marinum, initially infect, evade, and exploit macrophages, a major host defense against invading pathogens. Within macrophages, mycobacteria reside within host membrane-bound compartments called phagosomes. Mycobacterium-induced damage of the phagosomal membranes is integral to pathogenesis, and this activity has been attributed to the specialized mycobacterial secretion system ESX-1, and particularly to ESAT-6, its major secreted protein. Here, we show that the integrity of the unstructured ESAT-6 C terminus is required for macrophage phagosomal damage, granuloma formation, and virulence.
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Affiliation(s)
- Morwan M. Osman
- Molecular Immunity Unit, Cambridge Institute of Therapeutic Immunology and Infectious Diseases, Department of Medicine, University of Cambridge, CB2 OQH Cambridge, United Kingdom
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, United Kingdom
| | - Jonathan K. Shanahan
- Molecular Immunity Unit, Cambridge Institute of Therapeutic Immunology and Infectious Diseases, Department of Medicine, University of Cambridge, CB2 OQH Cambridge, United Kingdom
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, United Kingdom
| | - Frances Chu
- Department of Microbiology, University of Washington, Seattle, WA 98105
| | - Kevin K. Takaki
- Molecular Immunity Unit, Cambridge Institute of Therapeutic Immunology and Infectious Diseases, Department of Medicine, University of Cambridge, CB2 OQH Cambridge, United Kingdom
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, United Kingdom
| | - Malte L. Pinckert
- Molecular Immunity Unit, Cambridge Institute of Therapeutic Immunology and Infectious Diseases, Department of Medicine, University of Cambridge, CB2 OQH Cambridge, United Kingdom
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, United Kingdom
| | - Antonio J. Pagán
- Molecular Immunity Unit, Cambridge Institute of Therapeutic Immunology and Infectious Diseases, Department of Medicine, University of Cambridge, CB2 OQH Cambridge, United Kingdom
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, United Kingdom
| | - Roland Brosch
- Institut Pasteur, Université de Paris, CNRS UMR 3525, Unit for Integrated Mycobacterial Pathogenomics, 75724 Paris Cedex 15, France
| | - William H. Conrad
- Molecular Immunity Unit, Cambridge Institute of Therapeutic Immunology and Infectious Diseases, Department of Medicine, University of Cambridge, CB2 OQH Cambridge, United Kingdom
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, United Kingdom
| | - Lalita Ramakrishnan
- Molecular Immunity Unit, Cambridge Institute of Therapeutic Immunology and Infectious Diseases, Department of Medicine, University of Cambridge, CB2 OQH Cambridge, United Kingdom
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, United Kingdom
- Department of Microbiology, University of Washington, Seattle, WA 98105
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15
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Bendre AD, Peters PJ, Kumar J. Tuberculosis: Past, present and future of the treatment and drug discovery research. CURRENT RESEARCH IN PHARMACOLOGY AND DRUG DISCOVERY 2021; 2:100037. [PMID: 34909667 PMCID: PMC8663960 DOI: 10.1016/j.crphar.2021.100037] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 05/21/2021] [Accepted: 05/21/2021] [Indexed: 11/25/2022] Open
Abstract
Tuberculosis (TB) is an infectious disease caused by the bacterium Mycobacterium tuberculosis. Despite decades of research driving advancements in drug development and discovery against TB, it still leads among the causes of deaths due to infectious diseases. We are yet to develop an effective treatment course or a vaccine that could help us eradicate TB. Some key issues being prolonged treatment courses, inadequate drug intake, and the high dropout rate of patients during the treatment course. Hence, we require drugs that could accelerate the elimination of bacteria, shortening the treatment duration. It is high time we evaluate the probable lacunas in research holding us back in coming up with a treatment regime and/or a vaccine that would help control TB spread. Years of dedicated and focused research provide us with a lead molecule that goes through several tests, trials, and modifications to transform into a ‘drug’. The transformation from lead molecule to ‘drug’ is governed by several factors determining its success or failure. In the present review, we have discussed drugs that are part of the currently approved treatment regimen, their limitations, vaccine candidates under trials, and current issues in research that need to be addressed. While we are waiting for the path-breaking treatment for TB, these factors should be considered during the ongoing quest for novel yet effective anti-tubercular. If these issues are addressed, we could hope to develop a more effective treatment that would cure multi/extremely drug-resistant TB and help us meet the WHO's targets for controlling the global TB pandemic within the prescribed timeline. Despite numerous drugs and vaccines undergoing clinical trials, we have not been able to control TB. Majority of articles list the advancements in the TB drug-discovery; here we review the limitations of existing treatments. Brief description of aspects to be considered for the development of one but effective drug/preventive vaccine. A glance at pediatric tuberculosis: the most neglected area of TB research which requires dedicated research efforts. A concise narrative for research aspects to be re-evaluated by both academia and pharmaceutical R&D teams.
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Key Words
- BCG, Bacille Calmette-Guérin
- BDQ, Bedaquiline
- BSL, Biosafety level
- CDC, Center for Disease Control and Prevention
- Drug discovery
- Drug resistance
- EMB, Ethambutol
- ESX, ESAT-6 secretion system
- ETC, Electron transport chain
- ETH, Ethionamide
- FAS-1, Fatty acid synthase 1
- FDA, Food and Drug Administration
- INH, Isoniazid
- LPZ, Lansoprazole
- MDR, Multidrug-resistant
- Mtb, Mycobacterium tuberculosis
- POA, pyrazinoic acid
- PZA, Pyrazinamide
- RD, the region of differences
- RIF, Rifampicin
- T7SS, Type 7 secretion system
- TB treatment
- TB, Tuberculosis
- TST, Tuberculin skin test
- Tuberculosis
- WHO, World health organization
- XDR, Extremely drug-resistant
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Affiliation(s)
- Ameya D Bendre
- Laboratory of Membrane Protein Biology, National Centre for Cell Science, NCCS Complex, S. P. Pune University, Maharashtra, Pune, 411007, India
| | - Peter J Peters
- The Maastricht Multimodal Molecular Imaging Institute (M4I), Division of Nanoscopy, Maastricht University, Maastricht, the Netherlands
| | - Janesh Kumar
- Laboratory of Membrane Protein Biology, National Centre for Cell Science, NCCS Complex, S. P. Pune University, Maharashtra, Pune, 411007, India
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16
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Cheung CY, McNeil MB, Cook GM. Utilization of CRISPR interference to investigate the contribution of genes to pathogenesis in a macrophage model of Mycobacterium tuberculosis infection. J Antimicrob Chemother 2021; 77:615-619. [PMID: 34850009 DOI: 10.1093/jac/dkab437] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 10/29/2021] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVES There is an urgent need for novel drugs that target unique cellular pathways to combat infections caused by Mycobacterium tuberculosis. CRISPR interference (CRISPRi)-mediated transcriptional repression has recently been developed for use in mycobacteria as a genetic tool for identifying and validating essential genes as novel drug targets. Whilst CRISPRi has been applied to extracellular bacteria, no studies to date have determined whether CRISPRi can be used in M. tuberculosis infection models. METHODS Using the human monocytic macrophage-like THP-1 cell line as a model for M. tuberculosis infection we investigated if CRISPRi can be activated within intracellular M. tuberculosis. RESULTS The transcriptional repression of two candidate M. tuberculosis genes, i.e. mmpL3 and qcrB, leads to a reduction in viable M. tuberculosis within infected THP-1 cells. The reduction in viable colonies is dependent on both the level of CRISPRi-mediated repression and the duration of repression. CONCLUSIONS These results highlight the utility of CRISPRi in exploring mycobacterial gene function and essentiality under a variety of conditions pertinent to host infection.
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Affiliation(s)
- Chen-Yi Cheung
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Matthew B McNeil
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
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17
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Exploration of synergistic action of cell wall-degrading enzymes against Mycobacterium tuberculosis. Antimicrob Agents Chemother 2021; 65:e0065921. [PMID: 34280017 DOI: 10.1128/aac.00659-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Background The major global health threat tuberculosis is caused by Mycobacterium tuberculosis (Mtb). Mtb has a complex cell envelope - a partially covalently linked composite of polysaccharides, peptidoglycan and lipids, including a mycolic acid layer - which conveys pathogenicity but also protects against antibiotics. Given previous successes in treating gram-positive and -negative infections with cell wall degrading enzymes, we investigated such approach for Mtb. Objectives (i) Development of an Mtb microtiter growth inhibition assay that allows undisturbed cell envelope formation, to overcome the invalidation of results by typical clumped Mtb-growth in surfactant-free assays. (ii) Exploring anti-Mtb potency of cell wall layer-degrading enzymes. (iii) Investigation of the concerted action of several such enzymes. Methods We inserted a bacterial luciferase-operon in an auxotrophic Mtb strain to develop a microtiter assay that allows proper evaluation of cell wall degrading anti-Mtb enzymes. We assessed growth-inhibition by enzymes (recombinant mycobacteriophage mycolic acid esterase (LysB), fungal α-amylase and human and chicken egg white lysozymes) and combinations thereof, in presence or absence of biopharmaceutically acceptable surfactant. Results Our biosafety level-2 assay identified both LysB and lysozymes as potent Mtb-inhibitors, but only in presence of surfactant. Moreover, most potent disruption of the mycolic acid hydrophobic barrier was obtained by the highly synergistic combination of LysB, α-amylase and polysorbate 80. Conclusions Synergistically acting cell wall degrading enzymes are potently inhibiting Mtb - which sets the scene for the design of specifically tailored antimycobacterial (fusion) enzymes. Airway delivery of protein therapeutics has already been established and should be studied in animal models for active TB.
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18
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Sterilization by Adaptive Immunity of a Conditionally Persistent Mutant of Mycobacterium tuberculosis. mBio 2021; 12:mBio.02391-20. [PMID: 33468684 PMCID: PMC7845640 DOI: 10.1128/mbio.02391-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The bacterial pathogen Mycobacterium tuberculosis can enter into a persistent state in which M. tuberculosis can evade host immunity, thereby reducing the effectiveness of current tuberculosis vaccines. Understanding the factors that contribute to persistence would enable the rational design of vaccines effective against persisters. Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, can enter into a persistent state that confers resistance to antibacterial agents. Many observations suggest that persistent M. tuberculosis cells also evade the antimycobacterial immune mechanisms, thereby reducing the effectiveness of the current tuberculosis vaccine. Understanding the factors that contribute to persistence may enable the rational design of vaccines that stimulate effective immune killing mechanisms against persister cells. Independent mutations targeting the methionine and arginine biosynthetic pathways are bactericidal for M. tuberculosis in mice. However, in this study, we discovered that the addition of leucine and pantothenate auxotrophy altered the bactericidality of methionine auxotrophy. Whereas the leucine/pantothenate/methionine auxotrophic M. tuberculosis strain H37Rv ΔleuCD ΔpanCD ΔmetA was eliminated in immunocompetent mice, this strain persisted in multiple organs of immunodeficient Rag1−/− mice for at least a year. In contrast, the leucine/pantothenate/arginine auxotroph H37Rv ΔleuCD ΔpanCD ΔargB was eliminated in both immunocompetent and immunodeficient Rag1−/− mice. Our results showed that leucine and pantothenate starvation metabolically blocked the sterilization mechanisms of methionine starvation but not those of arginine starvation. These triple-auxotrophic strains should be invaluable tools for unravelling the bacterial and host factors that enable persistence and for vaccine development studies to assess the efficacy of vaccines that boost immune recognition of M. tuberculosis in the persistent state. The sterilization of the ΔleuCD ΔpanCD ΔmetA auxotroph in immunocompetent mice, but not in mice lacking an adaptive immune response, could provide a new system for studying the antimycobacterial killing mechanisms of adaptive immunity.
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19
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Allué-Guardia A, Saranathan R, Chan J, Torrelles JB. Mycobacteriophages as Potential Therapeutic Agents against Drug-Resistant Tuberculosis. Int J Mol Sci 2021; 22:ijms22020735. [PMID: 33450990 PMCID: PMC7828454 DOI: 10.3390/ijms22020735] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/05/2021] [Accepted: 01/08/2021] [Indexed: 01/21/2023] Open
Abstract
The current emergence of multi-, extensively-, extremely-, and total-drug resistant strains of Mycobacterium tuberculosis poses a major health, social, and economic threat, and stresses the need to develop new therapeutic strategies. The notion of phage therapy against bacteria has been around for more than a century and, although its implementation was abandoned after the introduction of drugs, it is now making a comeback and gaining renewed interest in Western medicine as an alternative to treat drug-resistant pathogens. Mycobacteriophages are genetically diverse viruses that specifically infect mycobacterial hosts, including members of the M. tuberculosis complex. This review describes general features of mycobacteriophages and their mechanisms of killing M. tuberculosis, as well as their advantages and limitations as therapeutic and prophylactic agents against drug-resistant M. tuberculosis strains. This review also discusses the role of human lung micro-environments in shaping the availability of mycobacteriophage receptors on the M. tuberculosis cell envelope surface, the risk of potential development of bacterial resistance to mycobacteriophages, and the interactions with the mammalian host immune system. Finally, it summarizes the knowledge gaps and defines key questions to be addressed regarding the clinical application of phage therapy for the treatment of drug-resistant tuberculosis.
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Affiliation(s)
- Anna Allué-Guardia
- Population Health Program, Tuberculosis Group, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
- Correspondence: (A.A.-G.); (J.B.T.)
| | - Rajagopalan Saranathan
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY 10461, USA; (R.S.); (J.C.)
| | - John Chan
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY 10461, USA; (R.S.); (J.C.)
| | - Jordi B. Torrelles
- Population Health Program, Tuberculosis Group, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
- Correspondence: (A.A.-G.); (J.B.T.)
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20
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Li Y, Keshavan P, Corro JH, Koripella RK, Agrawal RK, Ojha AK. Purification of Hibernating and Active C- Ribosomes from Zinc-Starved Mycobacteria. Methods Mol Biol 2021; 2314:151-166. [PMID: 34235651 DOI: 10.1007/978-1-0716-1460-0_5] [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] [Indexed: 01/03/2023]
Abstract
Zinc starvation in Mycobacterium smegmatis and Mycobacterium tuberculosis induces ribosome remodeling and hibernation. Remodeling involves replacement of C+ ribosomal (r-) proteins containing the zinc-binding CXXC motif with their C- paralogues without the motif. Hibernation is characterized by binding of mycobacterial-specific protein Y (Mpy) to 70S C- ribosomes, stabilizing the ribosome in an inactive state that is also resistant to kanamycin and streptomycin. We observed that ribosome remodeling and hibernation occur at two different concentrations of cellular zinc. Here, we describe the methods to purify hibernating and active forms of C- ribosomes from zinc-starved mycobacteria, along with purification of C+ ribosomes from zinc-rich mycobacterial cells. In vitro analysis of these distinct types of ribosomes will facilitate screening of small molecule inhibitors of ribosome hibernation for improved therapeutics against mycobacterial infections.
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Affiliation(s)
- Yunlong Li
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Pooja Keshavan
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Jamie H Corro
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY, USA
- Department of Biomedical Sciences, University at Albany, Albany, NY, USA
| | - Ravi K Koripella
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Rajendra K Agrawal
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY, USA
- Department of Biomedical Sciences, University at Albany, Albany, NY, USA
| | - Anil K Ojha
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY, USA.
- Department of Biomedical Sciences, University at Albany, Albany, NY, USA.
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21
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Yamada H, Chikamatsu K, Aono A, Murata K, Miyazaki N, Kayama Y, Bhatt A, Fujiwara N, Maeda S, Mitarai S. Fundamental Cell Morphologies Examined With Cryo-TEM of the Species in the Novel Five Genera Robustly Correlate With New Classification in Family Mycobacteriaceae. Front Microbiol 2020; 11:562395. [PMID: 33304323 PMCID: PMC7701246 DOI: 10.3389/fmicb.2020.562395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 10/12/2020] [Indexed: 11/25/2022] Open
Abstract
A recent study proposed the novel classification of the family Mycobacteriaceae based on the genome analysis of core proteins in 150 Mycobacterium species. The results from these analyses supported the existence of five distinct monophyletic groups within the genus Mycobacterium. That is, Mycobacterium has been divided into two novel genera for rapid grower Mycobacteroides and Mycolicibacterium, and into three genera for slow grower Mycolicibacter, Mycolicibacillus, and an emended genus Mycobacterium, which include all the major human pathogens. Here, cryo-TEM examinations of 1,816 cells of 31 species (34 strains) belonging to the five novel genera were performed. The fundamental morphological properties of every single cell, such as cell diameter, cell length, cell perimeter, cell circularity, and aspect ratio were measured and compared between these genera. In 50 comparisons on the five parameters between any two genera, only five comparisons showed “non-significant” differences. That is, there are non-significant differences between slow grower genus Mycolicibacillus and genus Mycobacterium in average cell diameter (p = 0.15), between rapid grower genus Mycobacteroides and slow grower genus Mycobacterium in average cell length (p > 0.24), between genus Mycobacteroides and genus Mycobacterium (p > 0.68) and between genus Mycolicibacter and genus Mycolicibacillus (p > 0.11) in average cell perimeter, and between genus Mycolicibacterium and genus Mycobacterium in circularity (p > 0.73). The other 45 comparisons showed significant differences between the genera. Genus Mycobacteroides showed the longest average cell diameter, whereas the genus Mycolicibacter showed the shortest average diameter. Genus Mycolicibacterium showed the most extended average cell length, perimeter, and aspect ratio, whereas the genus Mycolicibacillus showed the shortest average cell length, perimeter, and aspect ratio. Genus Mycolicibacillus showed the highest average cell circularity, whereas genus Mycobacterium showed the lowest average cell circularity. These fundamental morphological data strongly support the new classification in the family Mycobacteriaceae, and this classification is rational and effective in the study of the members of the family Mycobacteriaceae. Because both the genus Mycolicibacterium and the genus Mycobacterium contain many species and showed larger significant standard deviations in every parameter, these genera may be divided into novel genera which show common genotype and phenotypes in morphology and pathogenicity.
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Affiliation(s)
- Hiroyuki Yamada
- Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Tokyo, Japan
| | - Kinuyo Chikamatsu
- Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Tokyo, Japan
| | - Akio Aono
- Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Tokyo, Japan
| | - Kazuyoshi Murata
- Supportive Center for Brain Research, National Institute for Physiological Science, Okazaki, Japan
| | - Naoyuki Miyazaki
- Supportive Center for Brain Research, National Institute for Physiological Science, Okazaki, Japan.,Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Japan
| | | | - Apoorva Bhatt
- School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Nagatoshi Fujiwara
- Department of Food and Nutrition, Faculty of Contemporary Human Life Science, Tezukayama University, Nara, Japan
| | - Shinji Maeda
- Department of Pharmacy, Faculty of Pharmaceutical Science, Hokkaido University of Science, Sapporo, Japan
| | - Satoshi Mitarai
- Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Tokyo, Japan.,Department of Basic Mycobacteriology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
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22
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Nanoluciferase Reporter Mycobacteriophage for Sensitive and Rapid Detection of Mycobacterium tuberculosis Drug Susceptibility. J Bacteriol 2020; 202:JB.00411-20. [PMID: 32900827 PMCID: PMC7585058 DOI: 10.1128/jb.00411-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/01/2020] [Indexed: 01/02/2023] Open
Abstract
Mycobacterium tuberculosis, the causative agent of tuberculosis disease, remains a public health crisis on a global scale, and development of new interventions and identification of drug resistance are pillars in the World Health Organization End TB Strategy. Leveraging the tractability of the TM4 mycobacteriophage and the sensitivity of the nanoluciferase reporter enzyme, the present work describes an evolution of phage-mediated detection and drug susceptibility testing of M. tuberculosis, adding a valuable tool in drug discovery and basic biology research. With additional validation, this system may play a role as a quantitative phenotypic reference method and complement to genotypic methods for diagnosis and antibiotic susceptibility testing. Phenotypic testing for drug susceptibility of Mycobacterium tuberculosis is critical to basic research and managing the evolving problem of antimicrobial resistance in tuberculosis management, but it remains a specialized technique to which access is severely limited. Here, we report on the development and validation of an improved phage-mediated detection system for M. tuberculosis. We incorporated a nanoluciferase (Nluc) reporter gene cassette into the TM4 mycobacteriophage genome to create phage TM4-nluc. We assessed the performance of this reporter phage in the context of cellular limit of detection and drug susceptibility testing using multiple biosafety level 2 drug-sensitive and -resistant auxotrophs as well as virulent M. tuberculosis strains. For both limit of detection and drug susceptibility testing, we developed a standardized method consisting of a 96-hour cell preculture followed by a 72-hour experimental window for M. tuberculosis detection with or without antibiotic exposure. The cellular limit of detection of M. tuberculosis in a 96-well plate batch culture was ≤102 CFU. Consistent with other phenotypic methods for drug susceptibility testing, we found TM4-nluc to be compatible with antibiotics representing multiple classes and mechanisms of action, including inhibition of core central dogma functions, cell wall homeostasis, metabolic inhibitors, compounds currently in clinical trials (SQ109 and Q203), and susceptibility testing for bedaquiline, pretomanid, and linezolid (components of the BPaL regimen for the treatment of multi- and extensively drug-resistant tuberculosis). Using the same method, we accurately identified rifampin-resistant and multidrug-resistant M. tuberculosis strains. IMPORTANCEMycobacterium tuberculosis, the causative agent of tuberculosis disease, remains a public health crisis on a global scale, and development of new interventions and identification of drug resistance are pillars in the World Health Organization End TB Strategy. Leveraging the tractability of the TM4 mycobacteriophage and the sensitivity of the nanoluciferase reporter enzyme, the present work describes an evolution of phage-mediated detection and drug susceptibility testing of M. tuberculosis, adding a valuable tool in drug discovery and basic biology research. With additional validation, this system may play a role as a quantitative phenotypic reference method and complement to genotypic methods for diagnosis and antibiotic susceptibility testing.
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Characterization of Large Deletion Mutants of Mycobacterium tuberculosis Selected for Isoniazid Resistance. Antimicrob Agents Chemother 2020; 64:AAC.00792-20. [PMID: 32631825 DOI: 10.1128/aac.00792-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 06/30/2020] [Indexed: 01/10/2023] Open
Abstract
Large genomic deletions (LGDs) (6 to 63 kbp) were observed in isoniazid-resistant Mycobacterium tuberculosis mutants derived from four M. tuberculosis strains. These LGDs had no growth defect in vitro but could be defective in intracellular growth and showed various sensitivities toward oxidative stress despite lacking katG The LGD regions comprise 74 genes, mostly of unknown function, that may be important for M. tuberculosis intracellular growth and protection against oxidative stress.
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Porcelli SA, Jacobs WR. Exacting Edward Jenner's revenge: The quest for a new tuberculosis vaccine. Sci Transl Med 2020; 11:11/490/eaax4219. [PMID: 31043569 PMCID: PMC6943913 DOI: 10.1126/scitranslmed.aax4219] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 04/10/2019] [Indexed: 12/25/2022]
Abstract
Recent experimental and clinical work has reinvigorated the pursuit of a better tuberculosis vaccine.
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Affiliation(s)
- Steven A Porcelli
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - William R Jacobs
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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Vilchèze C, Jacobs WR. The Isoniazid Paradigm of Killing, Resistance, and Persistence in Mycobacterium tuberculosis. J Mol Biol 2019; 431:3450-3461. [PMID: 30797860 PMCID: PMC6703971 DOI: 10.1016/j.jmb.2019.02.016] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 02/05/2019] [Accepted: 02/11/2019] [Indexed: 12/20/2022]
Abstract
Isoniazid (INH) was the first synthesized drug that mediated bactericidal killing of the bacterium Mycobacterium tuberculosis, a major clinical breakthrough. To this day, INH remains a cornerstone of modern tuberculosis (TB) chemotherapy. This review describes the serendipitous discovery of INH, its effectiveness on TB patients, and early studies to discover its mechanisms of bacteriocidal activity. Forty years after its introduction as a TB drug, the development of gene transfer in mycobacteria enabled the discovery of the genes encoding INH resistance, namely, the activator (katG) and the target (inhA) of INH. Further biochemical and x-ray crystallography studies on KatG and InhA proteins and mutants provided comprehensive understanding of INH mode of action and resistance mechanisms. Bacterial cultures can harbor subpopulations that are genetically or phenotypically resistant cells, the latter known as persisters. Treatment of exponentially growing cultures of M. tuberculosis with INH reproducibly kills 99% to 99.9% of cells in 3 days. Importantly, the surviving cells are slowly replicating or non-replicating cells expressing a unique stress response signature: these are the persisters. These persisters can be visualized using dual-reporter mycobacteriophages and their formation prevented using reducing compounds, such as N-acetylcysteine or vitamin C, that enhance M. tuberculosis' respiration. Altogether, this review portrays a detailed molecular analysis of INH killing and resistance mechanisms including persistence. The phenomenon of persistence is clearly the single greatest impediment to TB control, and research aimed at understanding persistence will provide new strategies to improve TB chemotherapy.
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Affiliation(s)
- Catherine Vilchèze
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1301 Morris Park Avenue, Bronx, NY 10461, USA
| | - William R Jacobs
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1301 Morris Park Avenue, Bronx, NY 10461, USA.
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Mouton JM, Heunis T, Dippenaar A, Gallant JL, Kleynhans L, Sampson SL. Comprehensive Characterization of the Attenuated Double Auxotroph Mycobacterium tuberculosisΔ leuDΔ panCD as an Alternative to H37Rv. Front Microbiol 2019; 10:1922. [PMID: 31481950 PMCID: PMC6710366 DOI: 10.3389/fmicb.2019.01922] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 08/05/2019] [Indexed: 01/04/2023] Open
Abstract
Although currently available model organisms such as Mycobacterium smegmatis and Mycobacterium bovis Bacillus Calmette-Guérin (BCG) have significantly contributed to our understanding of tuberculosis (TB) biology, these models have limitations such as differences in genome size, growth rates and virulence. However, attenuated Mycobacterium tuberculosis strains may provide more representative, safer models to study M. tuberculosis biology. For example, the M. tuberculosis ΔleuDΔpanCD double auxotroph, has undergone rigorous in vitro and in vivo safety testing. Like other auxotrophic strains, this has subsequently been approved for use in biosafety level (BSL) 2 facilities. Auxotrophic strains have been assessed as models for drug-resistant M. tuberculosis and for studying latent TB. These offer the potential as safe and useful models, but it is important to understand how well these recapitulate salient features of non-attenuated M. tuberculosis. We therefore performed a comprehensive comparison of M. tuberculosis H37Rv and M. tuberculosisΔleuDΔpanCD. These strains demonstrated similar in vitro and intra-macrophage replication rates, similar responses to anti-TB agents and whole genome sequence conservation. Shotgun proteomics analysis suggested that M. tuberculosisΔleuDΔpanCD has a heightened stress response that leads to reduced bacterial replication during exposure to acid stress, which has been verified using a dual-fluorescent replication reporter assay. Importantly, infection of human peripheral blood mononuclear cells with the 2 strains elicited comparable cytokine production, demonstrating the suitability of M. tuberculosisΔleuDΔpanCD for immunological assays. We provide comprehensive evidence to support the judicious use of M. tuberculosisΔleuDΔpanCD as a safe and suitable model organism for M. tuberculosis research, without the need for a BSL3 facility.
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Affiliation(s)
- Jomien M Mouton
- Department of Science and Technology/National Research Foundation (DST/NRF) Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Tiaan Heunis
- Department of Science and Technology/National Research Foundation (DST/NRF) Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa.,Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Anzaan Dippenaar
- Department of Science and Technology/National Research Foundation (DST/NRF) Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - James L Gallant
- Department of Science and Technology/National Research Foundation (DST/NRF) Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa.,Section of Molecular Microbiology, Amsterdam Institute of Molecules, Medicines, and Systems, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Léanie Kleynhans
- Department of Science and Technology/National Research Foundation (DST/NRF) Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Samantha L Sampson
- Department of Science and Technology/National Research Foundation (DST/NRF) Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
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de Wet TJ, Warner DF, Mizrahi V. Harnessing Biological Insight to Accelerate Tuberculosis Drug Discovery. Acc Chem Res 2019; 52:2340-2348. [PMID: 31361123 PMCID: PMC6704484 DOI: 10.1021/acs.accounts.9b00275] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Tuberculosis (TB) is the leading cause of mortality globally resulting from an infectious disease, killing almost 1.6 million people annually and accounting for approximately 30% of deaths attributed to antimicrobial resistance (AMR). This despite the widespread administration of a neonatal vaccine, and the availability of an effective combination drug therapy against the causative agent, Mycobacterium tuberculosis (Mtb). Instead, TB prevalence worldwide is characterized by high-burden regions in which co-epidemics, such as HIV, and social and economic factors, undermine efforts to control TB. These elements additionally ensure conditions that favor the emergence of drug-resistant Mtb strains, which further threaten prospects for future TB control. To address this challenge, significant resources have been invested in developing a TB drug pipeline, an initiative given impetus by the recent regulatory approval of two new anti-TB drugs. However, both drugs have been reserved for drug-resistant disease, and the seeming inevitability of new resistance plus the recognized need to shorten the duration of chemotherapy demands continual replenishment of the pipeline with high-quality "hits" with novel mechanisms of action. This represents a massive challenge, which has been undermined by key gaps in our understanding of Mtb physiology and metabolism, especially during host infection. Whereas drug discovery for other bacterial infections can rely on predictive in vitro assays and animal models, for Mtb, inherent metabolic flexibility and uncertainties about the nutrients available to infecting bacilli in different host (micro)environments instead requires educated predictions or demonstrations of efficacy in animal models of arguable relevance to human disease. Even microbiological methods for enumeration of viable mycobacterial cells are fraught with complication. Our research has focused on elucidating those aspects of mycobacterial metabolism that contribute to the robustness of the bacillus to host immunological defenses and applied antibiotics and that, possibly, drive the emergence of drug resistance. This work has identified a handful of metabolic pathways that appear vulnerable to antibiotic targeting. Those highlighted, here, include the inter-related functions of pantothenate and coenzyme A biosynthesis and recycling and nucleotide metabolism-the last of which reinforces our view that DNA metabolism constitutes an under-explored area for new TB drug development. Although nonessential functions have traditionally been deprioritized for antibiotic development, a common theme emerging from this work is that these very functions might represent attractive targets because of the potential to cripple mechanisms critical to bacillary survival under stress (for example, the RelMtb-dependent stringent response) or to adaptability under unfavorable, potentially lethal, conditions including antibiotic therapy (for example, DnaE2-dependent SOS mutagenesis). The bar, however, is high: demonstrating convincingly the likely efficacy of this strategy will require innovative models of human TB disease. In the concluding section, we focus on the need for improved techniques to elucidate mycobacterial metabolism during infection and its impact on disease outcomes. Here, we argue that developments in other fields suggest the potential to break through this barrier by harnessing chemical-biology approaches in tandem with the most advanced technologies. As researchers based in a high-burden country, we are impelled to continue participating in this important endeavor.
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Affiliation(s)
- Timothy J. de Wet
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit and DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town 7925, South Africa
- Department of Integrative Biomedical Sciences, University of Cape Town, Observatory, Cape Town 7925, South Africa
| | - Digby F. Warner
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit and DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town 7925, South Africa
- Wellcome Centre for Infectious Disease Research in Africa, University of Cape Town, Observatory, Cape Town 7925, South Africa
| | - Valerie Mizrahi
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit and DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town 7925, South Africa
- Wellcome Centre for Infectious Disease Research in Africa, University of Cape Town, Observatory, Cape Town 7925, South Africa
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28
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Mashabela GT, de Wet TJ, Warner DF. Mycobacterium tuberculosis Metabolism. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0067-2019. [PMID: 31350832 PMCID: PMC10957194 DOI: 10.1128/microbiolspec.gpp3-0067-2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Indexed: 02/06/2023] Open
Abstract
Mycobacterium tuberculosis is the cause of tuberculosis (TB), a disease which continues to overwhelm health systems in endemic regions despite the existence of effective combination chemotherapy and the widespread use of a neonatal anti-TB vaccine. For a professional pathogen, M. tuberculosis retains a surprisingly large proportion of the metabolic repertoire found in nonpathogenic mycobacteria with very different lifestyles. Moreover, evidence that additional functions were acquired during the early evolution of the M. tuberculosis complex suggests the organism has adapted (and augmented) the metabolic pathways of its environmental ancestor to persistence and propagation within its obligate human host. A better understanding of M. tuberculosis pathogenicity, however, requires the elucidation of metabolic functions under disease-relevant conditions, a challenge complicated by limited knowledge of the microenvironments occupied and nutrients accessed by bacilli during host infection, as well as the reliance in experimental mycobacteriology on a restricted number of experimental models with variable relevance to clinical disease. Here, we consider M. tuberculosis metabolism within the framework of an intimate host-pathogen coevolution. Focusing on recent advances in our understanding of mycobacterial metabolic function, we highlight unusual adaptations or departures from the better-characterized model intracellular pathogens. We also discuss the impact of these mycobacterial "innovations" on the susceptibility of M. tuberculosis to existing and experimental anti-TB drugs, as well as strategies for targeting metabolic pathways. Finally, we offer some perspectives on the key gaps in the current knowledge of fundamental mycobacterial metabolism and the lessons which might be learned from other systems.
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Affiliation(s)
- Gabriel T Mashabela
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, South Africa
- Current address: Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, University of Stellenbosch, South Africa
| | - Timothy J de Wet
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, South Africa
- Department of Integrative Biomedical Sciences, University of Cape Town, South Africa
| | - Digby F Warner
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, South Africa
- Wellcome Centre for Infectious Disease Research in Africa, University of Cape Town, South Africa
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29
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Abstract
It is generally regarded that the progression of an infection within host macrophages is the consequence of a failed immune response. However, recent appreciation of macrophage heterogeneity, with respect to both development and metabolism, indicates that the reality is more complex. Different lineages of tissue-resident macrophages respond divergently to microbial, environmental and immunological stimuli. The emerging picture that the developmental origin of macrophages determines their responses to immune stimulation and to infection stresses the importance of in vivo infection models. Recent investigations into the metabolism of infecting microorganisms and host macrophages indicate that their metabolic interface can be a major determinant of pathogen growth or containment. This Review focuses on the integration of data from existing studies, the identification of challenges in generating and interpreting data from ongoing studies and a discussion of the technologies and tools that are required to best address future questions in the field.
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Affiliation(s)
- David G Russell
- Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
| | - Lu Huang
- Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Brian C VanderVen
- Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
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