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Bates TA, Trank-Greene M, Nguyenla X, Anastas A, Gurmessa SK, Merutka IR, Dixon SD, Shumate A, Groncki AR, Parson MAH, Ingram JR, Barklis E, Burke JE, Shinde U, Ploegh HL, Tafesse FG. ESAT-6 undergoes self-association at phagosomal pH and an ESAT-6-specific nanobody restricts M. tuberculosis growth in macrophages. eLife 2024; 12:RP91930. [PMID: 38805257 PMCID: PMC11132683 DOI: 10.7554/elife.91930] [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: 05/29/2024] Open
Abstract
Mycobacterium tuberculosis (Mtb) is known to survive within macrophages by compromising the integrity of the phagosomal compartment in which it resides. This activity primarily relies on the ESX-1 secretion system, predominantly involving the protein duo ESAT-6 and CFP-10. CFP-10 likely acts as a chaperone, while ESAT-6 likely disrupts phagosomal membrane stability via a largely unknown mechanism. we employ a series of biochemical analyses, protein modeling techniques, and a novel ESAT-6-specific nanobody to gain insight into the ESAT-6's mode of action. First, we measure the binding kinetics of the tight 1:1 complex formed by ESAT-6 and CFP-10 at neutral pH. Subsequently, we demonstrate a rapid self-association of ESAT-6 into large complexes under acidic conditions, leading to the identification of a stable tetrameric ESAT-6 species. Using molecular dynamics simulations, we pinpoint the most probable interaction interface. Furthermore, we show that cytoplasmic expression of an anti-ESAT-6 nanobody blocks Mtb replication, thereby underlining the pivotal role of ESAT-6 in intracellular survival. Together, these data suggest that ESAT-6 acts by a pH-dependent mechanism to establish two-way communication between the cytoplasm and the Mtb-containing phagosome.
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Affiliation(s)
- Timothy A Bates
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - Mila Trank-Greene
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - Xammy Nguyenla
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - Aidan Anastas
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - Sintayehu K Gurmessa
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - Ilaria R Merutka
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - Shandee D Dixon
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - Anthony Shumate
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science UniversityPortlandUnited States
| | - Abigail R Groncki
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - Matthew AH Parson
- Department of Biochemistry and Microbiology, University of VictoriaVictoriaCanada
| | - Jessica R Ingram
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Harvard Medical SchoolBostonUnited States
| | - Eric Barklis
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - John E Burke
- Department of Biochemistry and Microbiology, University of VictoriaVictoriaCanada
- Department of Biochemistry and Molecular Biology, The University of British ColumbiaVancouverCanada
| | - Ujwal Shinde
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science UniversityPortlandUnited States
| | - Hidde L Ploegh
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Harvard Medical SchoolBostonUnited States
| | - Fikadu G Tafesse
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
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2
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Gupta VK, Vaishnavi VV, Arrieta-Ortiz ML, P S A, K M J, Jeyasankar S, Raghunathan V, Baliga NS, Agarwal R. 3D Hydrogel Culture System Recapitulates Key Tuberculosis Phenotypes and Demonstrates Pyrazinamide Efficacy. Adv Healthc Mater 2024:e2304299. [PMID: 38655817 DOI: 10.1002/adhm.202304299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 03/29/2024] [Indexed: 04/26/2024]
Abstract
The mortality caused by tuberculosis (TB) infections is a global concern, and there is a need to improve understanding of the disease. Current in vitro infection models to study the disease have limitations such as short investigation durations and divergent transcriptional signatures. This study aims to overcome these limitations by developing a 3D collagen culture system that mimics the biomechanical and extracellular matrix (ECM) of lung microenvironment (collagen fibers, stiffness comparable to in vivo conditions) as the infection primarily manifests in the lungs. The system incorporates Mycobacterium tuberculosis (Mtb) infected human THP-1 or primary monocytes/macrophages. Dual RNA sequencing reveals higher mammalian gene expression similarity with patient samples than 2D macrophage infections. Similarly, bacterial gene expression more accurately recapitulates in vivo gene expression patterns compared to bacteria in 2D infection models. Key phenotypes observed in humans, such as foamy macrophages and mycobacterial cords, are reproduced in the model. This biomaterial system overcomes challenges associated with traditional platforms by modulating immune cells and closely mimicking in vivo infection conditions, including showing efficacy with clinically relevant concentrations of anti-TB drug pyrazinamide, not seen in any other in vitro infection model, making it reliable and readily adoptable for tuberculosis studies and drug screening.
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Affiliation(s)
- Vishal K Gupta
- Department of Bioengineering, Indian Institute of Science, CV Raman Road, Bengaluru, Karnataka, 560012, India
| | - Vijaya V Vaishnavi
- Department of Bioengineering, Indian Institute of Science, CV Raman Road, Bengaluru, Karnataka, 560012, India
| | | | - Abhirami P S
- Department of Bioengineering, Indian Institute of Science, CV Raman Road, Bengaluru, Karnataka, 560012, India
| | - Jyothsna K M
- Department of Electrical Communication Engineering, Indian Institute of Science, CV Raman Road, Bengaluru, Karnataka, 560012, India
| | - Sharumathi Jeyasankar
- Department of Bioengineering, Indian Institute of Science, CV Raman Road, Bengaluru, Karnataka, 560012, India
| | - Varun Raghunathan
- Department of Electrical Communication Engineering, Indian Institute of Science, CV Raman Road, Bengaluru, Karnataka, 560012, India
| | - Nitin S Baliga
- Institute of Systems Biology, 401 Terry Ave N, Seattle, WA, 98109, USA
| | - Rachit Agarwal
- Department of Bioengineering, Indian Institute of Science, CV Raman Road, Bengaluru, Karnataka, 560012, India
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3
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Martinena CB, Corleto M, Martínez MMB, Amiano NO, García VE, Maffia PC, Tateosian NL. Antimicrobial Effect of Cannabidiol on Intracellular Mycobacterium tuberculosis. Cannabis Cannabinoid Res 2024; 9:464-469. [PMID: 38252548 DOI: 10.1089/can.2023.0124] [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: 01/24/2024] Open
Abstract
Introduction: Mycobacterium tuberculosis, the etiologic agent of tuberculosis (TB), has killed nearly one billion people during the last two centuries. Nowadays, TB remains a major global health problem ranked among the top 10 causes of death worldwide. One of the main challenges in developing new strategies to fight TB is focused on reducing the duration and complexity of drug regimens. Cannabidiol (CBD) is the main nonpsychoactive ingredient extracted from the Cannabis sativa L. plant, which has been shown to be biologically active against bacteria. The purpose of this work was to investigate the antimicrobial effect of CBD on M. tuberculosis intracellular infection. Materials and Methods: To assess the minimum inhibitory concentration (MIC) of CBD on mycobacterial strains, the MTT assay was performed on Mycobacterium smegmatis, and the Colony-Forming Unit (CFU) assay was conducted on MtbH37Rv. Additionally, the cytotoxic effect of CBD on THP-1 cells was assessed by MTT assay. Moreover, macrophages derived from the THP-1 cell were infected with MtbH37Rv (multiplicity of infection 1:10) to evaluate the intracellular activity of CBD by determining the CFU/mL. Results: Antimicrobial activity against M. smegmatis (MIC=100 μM) and MtbH37Rv (MIC=25 μM) cultures was exhibited by CBD. Furthermore, the effect of CBD was also evaluated on MtbH37Rv infected macrophage cells. Interestingly, a reduction in viable intracellular MtbH37Rv bacteria was observed after 24 h of treatment. Moreover, CBD exhibited a safe profile toward human THP-1 cells, since it showed no toxicity (CC50=1075 μM) at a concentration of antibacterial effect (selectivity index 43). Conclusion: These results extend the knowledge regarding the antimicrobial activity of CBD and demonstrate its ability to kill the human intracellular pathogen M. tuberculosis.
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Affiliation(s)
- Camila Belen Martinena
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Merlina Corleto
- Laboratorio de Aplicaciones Biotecnológicas y Microbiologia, Universidad Nacional de Hurlingham, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET, Buenos Aires, Argentina
| | - Melina María Belén Martínez
- Laboratorio de Aplicaciones Biotecnológicas y Microbiologia, Universidad Nacional de Hurlingham, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET, Buenos Aires, Argentina
| | - Nicolás Oscar Amiano
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Verónica Edith García
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Paulo Cesar Maffia
- Laboratorio de Aplicaciones Biotecnológicas y Microbiologia, Universidad Nacional de Hurlingham, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET, Buenos Aires, Argentina
| | - Nancy Liliana Tateosian
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
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4
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Fontes FL, Rooker SA, Lynn-Barbe JK, Lyons MA, Crans DC, Crick DC. Pyrazinoic acid, the active form of the anti-tuberculosis drug pyrazinamide, and aromatic carboxylic acid analogs are protonophores. Front Mol Biosci 2024; 11:1350699. [PMID: 38414662 PMCID: PMC10896915 DOI: 10.3389/fmolb.2024.1350699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 01/16/2024] [Indexed: 02/29/2024] Open
Abstract
Pyrazinoic acid is the active form of pyrazinamide, a first-line antibiotic used to treat Mycobacterium tuberculosis infections. However, the mechanism of action of pyrazinoic acid remains a subject of debate, and alternatives to pyrazinamide in cases of resistance are not available. The work presented here demonstrates that pyrazinoic acid and known protonophores including salicylic acid, benzoic acid, and carbonyl cyanide m-chlorophenyl hydrazone all exhibit pH-dependent inhibition of mycobacterial growth activity over a physiologically relevant range of pH values. Other anti-tubercular drugs, including rifampin, isoniazid, bedaquiline, and p-aminosalicylic acid, do not exhibit similar pH-dependent growth-inhibitory activities. The growth inhibition curves of pyrazinoic, salicylic, benzoic, and picolinic acids, as well as carbonyl cyanide m-chlorophenyl hydrazone, all fit a quantitative structure-activity relationship (QSAR) derived from acid-base equilibria with R2 values > 0.95. The QSAR model indicates that growth inhibition relies solely on the concentration of the protonated forms of these weak acids (rather than the deprotonated forms). Moreover, pyrazinoic acid, salicylic acid, and carbonyl cyanide m-chlorophenyl hydrazone all caused acidification of the mycobacterial cytoplasm at concentrations that inhibit bacterial growth. Thus, it is concluded that pyrazinoic acid acts as an uncoupler of oxidative phosphorylation and that disruption of proton motive force is the primary mechanism of action of pyrazinoic acid rather than the inhibition of a classic enzyme activity.
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Affiliation(s)
- Fabio L. Fontes
- Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO, United States
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Steven A. Rooker
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Jamie K. Lynn-Barbe
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Michael A. Lyons
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Debbie C. Crans
- Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO, United States
- Department of Chemistry, Colorado State University, Fort Collins, CO, United States
| | - Dean C. Crick
- Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO, United States
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
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5
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Toniolo C, Sage D, McKinney JD, Dhar N. Quantification of Mycobacterium tuberculosis Growth in Cell-Based Infection Assays by Time-Lapse Fluorescence Microscopy. Methods Mol Biol 2024; 2813:167-188. [PMID: 38888778 DOI: 10.1007/978-1-0716-3890-3_12] [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: 06/20/2024]
Abstract
Quantification of Mycobacterium tuberculosis (Mtb) growth dynamics in cell-based in vitro infection models is traditionally carried out by measurement of colony forming units (CFU). However, Mtb being an extremely slow growing organism (16-24 h doubling time), this approach requires at least 3 weeks of incubation to obtain measurable readouts. In this chapter, we describe an alternative approach based on time-lapse microscopy and quantitative image analysis that allows faster quantification of Mtb growth dynamics in host cells. In addition, this approach provides the capability to capture other readouts from the same experimental setup, such as host cell viability, bacterial localization as well as the dynamics of propagation of infection between the host cells.
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Affiliation(s)
- Chiara Toniolo
- School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), Lausanne, Switzerland
| | - Daniel Sage
- Biomedical Imaging Group, School of Engineering, Swiss Federal Institute of Technology in Lausanne (EPFL), Lausanne, Switzerland
| | - John D McKinney
- School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), Lausanne, Switzerland
| | - Neeraj Dhar
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, SK, Canada.
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada.
- School of Public Health, University of Saskatchewan, Saskatoon, SK, Canada.
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6
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Maxouri O, Bodalal Z, Daal M, Rostami S, Rodriguez I, Akkari L, Srinivas M, Bernards R, Beets-Tan R. How to 19F MRI: applications, technique, and getting started. BJR Open 2023; 5:20230019. [PMID: 37953866 PMCID: PMC10636348 DOI: 10.1259/bjro.20230019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 07/26/2023] [Accepted: 08/01/2023] [Indexed: 11/14/2023] Open
Abstract
Magnetic resonance imaging (MRI) plays a significant role in the routine imaging workflow, providing both anatomical and functional information. 19F MRI is an evolving imaging modality where instead of 1H, 19F nuclei are excited. As the signal from endogenous 19F in the body is negligible, exogenous 19F signals obtained by 19F radiofrequency coils are exceptionally specific. Highly fluorinated agents targeting particular biological processes (i.e., the presence of immune cells) have been visualised using 19F MRI, highlighting its potential for non-invasive and longitudinal molecular imaging. This article aims to provide both a broad overview of the various applications of 19F MRI, with cancer imaging as a focus, as well as a practical guide to 19F imaging. We will discuss the essential elements of a 19F system and address common pitfalls during acquisition. Last but not least, we will highlight future perspectives that will enhance the role of this modality. While not an exhaustive exploration of all 19F literature, we endeavour to encapsulate the broad themes of the field and introduce the world of 19F molecular imaging to newcomers. 19F MRI bridges several domains, imaging, physics, chemistry, and biology, necessitating multidisciplinary teams to be able to harness this technology effectively. As further technical developments allow for greater sensitivity, we envision that 19F MRI can help unlock insight into biological processes non-invasively and longitudinally.
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Affiliation(s)
| | | | | | | | | | - Leila Akkari
- Division of Tumor Biology and Immunology, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | | | - René Bernards
- Division of Molecular Carcinogenesis, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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7
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Finin P, Khan RMN, Oh S, Boshoff HIM, Barry CE. Chemical approaches to unraveling the biology of mycobacteria. Cell Chem Biol 2023; 30:420-435. [PMID: 37207631 PMCID: PMC10201459 DOI: 10.1016/j.chembiol.2023.04.014] [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: 02/06/2023] [Revised: 04/07/2023] [Accepted: 04/27/2023] [Indexed: 05/21/2023]
Abstract
Mycobacterium tuberculosis (Mtb), perhaps more than any other organism, is intrinsically appealing to chemical biologists. Not only does the cell envelope feature one of the most complex heteropolymers found in nature1 but many of the interactions between Mtb and its primary host (we humans) rely on lipid and not protein mediators.2,3 Many of the complex lipids, glycolipids, and carbohydrates biosynthesized by the bacterium still have unknown functions, and the complexity of the pathological processes by which tuberculosis (TB) disease progress offers many opportunities for these molecules to influence the human response. Because of the importance of TB in global public health, chemical biologists have applied a wide-ranging array of techniques to better understand the disease and improve interventions.
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Affiliation(s)
- Peter Finin
- Tuberculosis Research Section, Laboratory of Clinical Immunology and Microbiology, NIAID, NIH, Bethesda, MD, USA
| | - R M Naseer Khan
- Tuberculosis Research Section, Laboratory of Clinical Immunology and Microbiology, NIAID, NIH, Bethesda, MD, USA
| | - Sangmi Oh
- Tuberculosis Research Section, Laboratory of Clinical Immunology and Microbiology, NIAID, NIH, Bethesda, MD, USA
| | - Helena I M Boshoff
- Tuberculosis Research Section, Laboratory of Clinical Immunology and Microbiology, NIAID, NIH, Bethesda, MD, USA
| | - Clifton E Barry
- Tuberculosis Research Section, Laboratory of Clinical Immunology and Microbiology, NIAID, NIH, Bethesda, MD, USA.
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8
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Zhu J, Liu YJ, Fortune SM. Spatiotemporal perspectives on tuberculosis chemotherapy. Curr Opin Microbiol 2023; 72:102266. [PMID: 36745965 PMCID: PMC10023397 DOI: 10.1016/j.mib.2023.102266] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 01/04/2023] [Indexed: 02/05/2023]
Abstract
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), accounts for over ten million infections and over 1.5 million deaths every year [1]. Upon infection, the seesaw between Mtb and our immune systems creates microenvironments that are compositionally distinctive and changing over time. While the field has begun to better understand the spatial complexity of TB disease, our understanding and experimental dissection of the temporal dynamics of TB and TB drug treatment is much more rudimentary. However, it is the combined spatiotemporal heterogeneity of TB disease that creates niches and time windows within which the pathogen can survive and thrive during treatment. Here, we review the emerging data on the interactions of spatial and temporal dynamics as they relate to TB disease and treatment. A better understanding of the interactions of Mtb, host, and antibiotics through space and time will elucidate treatment failure and potentially identify opportunities for new TB treatment regimens.
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Affiliation(s)
- Junhao Zhu
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, USA
| | - Yue J Liu
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, USA
| | - Sarah M Fortune
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, USA; Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA.
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9
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Mansat M, Dayam RM, Botelho RJ. Quantitative Immunofluorescence to Study Phagosome Maturation and Resolution. Methods Mol Biol 2023; 2692:121-137. [PMID: 37365465 DOI: 10.1007/978-1-0716-3338-0_9] [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: 06/28/2023]
Abstract
Cells such as macrophages and neutrophils can internalize a diverse set of particulate matter, illustrated by bacteria and apoptotic bodies through the process of phagocytosis. These particles are sequestered into phagosomes, which then fuse with early and late endosomes and ultimately with lysosomes to mature into phagolysosomes, through a process known as phagosome maturation. Ultimately, after particle degradation, phagosomes then fragment to reform lysosomes through phagosome resolution. As phagosomes change, they acquire and divest proteins that are associated with the various stages of phagosome maturation and resolution. These changes can be assessed at the single-phagosome level by using immunofluorescence methods. Typically, we use indirect immunofluorescence methods that rely on primary antibodies against specific molecular markers that track phagosome maturation. Commonly, progression of phagosomes into phagolysosomes can be determined by staining cells for Lysosomal-Associated Membrane Protein I (LAMP1) and measuring the fluorescence intensity of LAMP1 around each phagosome by microscopy or flow cytometry. However, this method can be used to detect any molecular marker for which there are compatible antibodies for immunofluorescence.
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Affiliation(s)
- Mélanie Mansat
- Department of Chemistry and Biology and the Graduate Program in Molecular Science, Toronto Metropolitan University, Toronto, ON, Canada
| | - Roya M Dayam
- Department of Chemistry and Biology and the Graduate Program in Molecular Science, Toronto Metropolitan University, Toronto, ON, Canada
| | - Roberto J Botelho
- Department of Chemistry and Biology and the Graduate Program in Molecular Science, Toronto Metropolitan University, Toronto, ON, Canada.
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10
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Aylan B, Botella L, Gutierrez MG, Santucci P. High content quantitative imaging of Mycobacterium tuberculosis responses to acidic microenvironments within human macrophages. FEBS Open Bio 2022. [PMID: 36520007 DOI: 10.1002/2211-5463.13537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/30/2022] [Accepted: 12/04/2022] [Indexed: 12/23/2022] Open
Abstract
Intracellular pathogens such as Mycobacterium tuberculosis (Mtb) have evolved diverse strategies to counteract macrophage defence mechanisms including phagolysosomal biogenesis. Within macrophages, Mtb initially resides inside membrane-bound phagosomes that interact with lysosomes and become acidified. The ability of Mtb to control and subvert the fusion between phagosomes and lysosomes plays a key role in the pathogenesis of tuberculosis. Therefore, understanding how pathogens interact with the endolysosomal network and cope with intracellular acidification is important to better understand the disease. Here, we describe in detail the use of fluorescence microscopy-based approaches to investigate Mtb responses to acidic environments in cellulo. We report high-content imaging modalities to probe Mtb sensing of external pH or visualise in real-time Mtb intrabacterial pH within infected human macrophages. We discuss various methodologies with step-by-step analyses that enable robust image-based quantifications. Finally, we highlight the advantages and limitations of these different approaches and discuss potential alternatives that can be applied to further investigate Mtb-host cell interactions. These methods can be adapted to study host-pathogen interactions in different biological systems and experimental settings. Altogether, these approaches represent a valuable tool to further broaden our understanding of the cellular and molecular mechanisms underlying intracellular pathogen survival.
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Affiliation(s)
- Beren Aylan
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, UK
| | - Laure Botella
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, UK
| | - Maximiliano G Gutierrez
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, UK
| | - Pierre Santucci
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, UK
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11
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Samuels AN, Wang ER, Harrison GA, Valenta JC, Stallings CL. Understanding the contribution of metabolism to Mycobacterium tuberculosis drug tolerance. Front Cell Infect Microbiol 2022; 12:958555. [PMID: 36072222 PMCID: PMC9441742 DOI: 10.3389/fcimb.2022.958555] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 07/29/2022] [Indexed: 11/29/2022] Open
Abstract
Treatment of Mycobacterium tuberculosis (Mtb) infections is particularly arduous. One challenge to effectively treating tuberculosis is that drug efficacy in vivo often fails to match drug efficacy in vitro. This is due to multiple reasons, including inadequate drug concentrations reaching Mtb at the site of infection and physiological changes of Mtb in response to host derived stresses that render the bacteria more tolerant to antibiotics. To more effectively and efficiently treat tuberculosis, it is necessary to better understand the physiologic state of Mtb that promotes drug tolerance in the host. Towards this end, multiple studies have converged on bacterial central carbon metabolism as a critical contributor to Mtb drug tolerance. In this review, we present the evidence that changes in central carbon metabolism can promote drug tolerance, depending on the environment surrounding Mtb. We posit that these metabolic pathways could be potential drug targets to stymie the development of drug tolerance and enhance the efficacy of current antimicrobial therapy.
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Affiliation(s)
| | | | | | | | - Christina L. Stallings
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO, United States
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