1
|
Wang X, Shang D, Chen J, Cheng S, Chen D, Zhang Z, Liu C, Yu J, Cao H, Li L, Li L. Serum metabolomics reveals the effectiveness of human placental mesenchymal stem cell therapy for Crohn's disease. Talanta 2024; 277:126442. [PMID: 38897006 DOI: 10.1016/j.talanta.2024.126442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 06/10/2024] [Accepted: 06/15/2024] [Indexed: 06/21/2024]
Abstract
Mesenchymal stem cell (MSC) therapy offers a promising cure for Crohn's disease (CD), however, its therapeutic effects vary significantly due to individual differences. Therefore, identifying easily detectable biomarkers is essential to assess the efficacy of MSC therapy. In this study, SAMP1/Yit mice were used as a model of CD, which develop spontaneous chronic ileitis, closely resembling the characteristics present in CD patients. Serum metabolic alterations during treatment were analyzed, through the application of differential 12C-/13C-dansylation labeling liquid chromatography-mass spectrometry. Based on the significant differences and time-varying trends of serum amine/phenol-containing metabolites abundance between the control group, the model group, and the treatment group, four serum biomarkers were ultimately screened for evaluating the efficacy of MSC treatment for CD, namely 4-hydroxyphenylpyruvate, 4-hydroxyphenylacetaldehyde, caffeate, and N-acetyltryptamine, whose abundances both increased in the serum of CD model mice and decreased after MSC treatment. These metabolic alterations were associated with tyrosine metabolism, which was validated by the dysregulation of related enzymes. The discovery of biomarkers may help to improve the targeting and effectiveness of treatment and provide innovative prospects for the clinical application of MSC for CD.
Collapse
Affiliation(s)
- Xiao Wang
- Jinan Microecological Biomedicine Shandong Laboratory, Jinan City 250117, China
| | - Dandan Shang
- Jinan Microecological Biomedicine Shandong Laboratory, Jinan City 250117, China
| | - Junyao Chen
- State Key Laboratory for the Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, 79 Qingchun Rd., Hangzhou City 310003, China
| | - Sheng Cheng
- State Key Laboratory for the Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, 79 Qingchun Rd., Hangzhou City 310003, China
| | - Deying Chen
- State Key Laboratory for the Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, 79 Qingchun Rd., Hangzhou City 310003, China
| | - Zhehua Zhang
- State Key Laboratory for the Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, 79 Qingchun Rd., Hangzhou City 310003, China
| | - Chaoxu Liu
- Department of Colorectal Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, 79 Qingchun Rd., Hangzhou City 310003, China
| | - Jiong Yu
- Jinan Microecological Biomedicine Shandong Laboratory, Jinan City 250117, China; State Key Laboratory for the Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, 79 Qingchun Rd., Hangzhou City 310003, China; Zhejiang Key Laboratory for Diagnosis and Treatment of Physic-chemical and Aging-related Injuries, 79 Qingchun Rd, Hangzhou City 310003, China.
| | - Hongcui Cao
- Jinan Microecological Biomedicine Shandong Laboratory, Jinan City 250117, China; State Key Laboratory for the Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, 79 Qingchun Rd., Hangzhou City 310003, China; Zhejiang Key Laboratory for Diagnosis and Treatment of Physic-chemical and Aging-related Injuries, 79 Qingchun Rd, Hangzhou City 310003, China.
| | - Liang Li
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
| | - Lanjuan Li
- Jinan Microecological Biomedicine Shandong Laboratory, Jinan City 250117, China; State Key Laboratory for the Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, 79 Qingchun Rd., Hangzhou City 310003, China
| |
Collapse
|
2
|
Strong EJ, Tan L, Hayes S, Whyte H, Davis RA, West NP. Identification of Axinellamines A and B as Anti-Tubercular Agents. Mar Drugs 2024; 22:298. [PMID: 39057407 PMCID: PMC11277618 DOI: 10.3390/md22070298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Revised: 06/18/2024] [Accepted: 06/19/2024] [Indexed: 07/28/2024] Open
Abstract
Tuberculosis remains a significant global health pandemic. There is an urgent need for new anti-tubercular agents to combat the rising incidence of drug resistance and to offer effective and additive therapeutic options. High-throughput screening of a subset of the NatureBank marine fraction library (n = 2000) identified a sample derived from an Australian marine sponge belonging to the order Haplosclerida that displayed promising anti-mycobacterial activity. Bioassay-guided fractionation of the organic extract from this Haplosclerida sponge led to the purification of previously identified antimicrobial pyrrole alkaloids, axinellamines A (1) and B (2). The axinellamine compounds were found to have a 90% minimum inhibitory concentration (MIC90) of 18 µM and 15 µM, respectively. The removal of protein and complex carbon sources reduced the MIC90 of 1 and 2 to 0.6 and 0.8 µM, respectively. The axinellamines were not toxic to mammalian cells at 25 µM and significantly reduced the intracellular bacterial load by >5-fold. These data demonstrate that axinellamines A and B are effective anti-tubercular agents and promising targets for future medicinal chemistry efforts.
Collapse
Affiliation(s)
- Emily J. Strong
- School of Chemistry and Molecular Biosciences, and the Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Lendl Tan
- School of Chemistry and Molecular Biosciences, and the Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Sasha Hayes
- Griffith Institute for Drug Discovery, School of Environment and Science, Griffith University, Brisbane, QLD 4111, Australia
- NatureBank, Griffith University, Brisbane, QLD 4111, Australia
| | - Hayden Whyte
- School of Chemistry and Molecular Biosciences, and the Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Rohan A. Davis
- Griffith Institute for Drug Discovery, School of Environment and Science, Griffith University, Brisbane, QLD 4111, Australia
- NatureBank, Griffith University, Brisbane, QLD 4111, Australia
| | - Nicholas P. West
- School of Chemistry and Molecular Biosciences, and the Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| |
Collapse
|
3
|
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.
Collapse
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.
| |
Collapse
|
4
|
Block AM, Wiegert PC, Namugenyi SB, Tischler AD. Transposon sequencing reveals metabolic pathways essential for Mycobacterium tuberculosis infection. PLoS Pathog 2024; 20:e1011663. [PMID: 38498580 PMCID: PMC10977890 DOI: 10.1371/journal.ppat.1011663] [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: 09/06/2023] [Revised: 03/28/2024] [Accepted: 02/26/2024] [Indexed: 03/20/2024] Open
Abstract
New drugs are needed to shorten and simplify treatment of tuberculosis caused by Mycobacterium tuberculosis. Metabolic pathways that M. tuberculosis requires for growth or survival during infection represent potential targets for anti-tubercular drug development. Genes and metabolic pathways essential for M. tuberculosis growth in standard laboratory culture conditions have been defined by genome-wide genetic screens. However, whether M. tuberculosis requires these essential genes during infection has not been comprehensively explored because mutant strains cannot be generated using standard methods. Here we show that M. tuberculosis requires the phenylalanine (Phe) and de novo purine and thiamine biosynthetic pathways for mammalian infection. We used a defined collection of M. tuberculosis transposon (Tn) mutants in essential genes, which we generated using a custom nutrient-rich medium, and transposon sequencing (Tn-seq) to identify multiple central metabolic pathways required for fitness in a mouse infection model. We confirmed by individual retesting and complementation that mutations in pheA (Phe biosynthesis) or purF (purine and thiamine biosynthesis) cause death of M. tuberculosis in the absence of nutrient supplementation in vitro and strong attenuation in infected mice. Our findings show that Tn-seq with defined Tn mutant pools can be used to identify M. tuberculosis genes required during mouse lung infection. Our results also demonstrate that M. tuberculosis requires Phe and purine/thiamine biosynthesis for survival in the host, implicating these metabolic pathways as prime targets for the development of new antibiotics to combat tuberculosis.
Collapse
Affiliation(s)
- Alisha M. Block
- Department of Microbiology and Immunology, University of Minnesota, Twin Cities Campus, Minneapolis, Minnesota, United States of America
| | - Parker C. Wiegert
- Department of Microbiology and Immunology, University of Minnesota, Twin Cities Campus, Minneapolis, Minnesota, United States of America
| | - Sarah B. Namugenyi
- Department of Microbiology and Immunology, University of Minnesota, Twin Cities Campus, Minneapolis, Minnesota, United States of America
| | - Anna D. Tischler
- Department of Microbiology and Immunology, University of Minnesota, Twin Cities Campus, Minneapolis, Minnesota, United States of America
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Bobba S, Khader SA. Rifampicin drug resistance and host immunity in tuberculosis: more than meets the eye. Trends Immunol 2023; 44:712-723. [PMID: 37543504 PMCID: PMC11170062 DOI: 10.1016/j.it.2023.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 07/11/2023] [Accepted: 07/12/2023] [Indexed: 08/07/2023]
Abstract
Tuberculosis (TB) is the leading cause of death due to an infectious agent, with more than 1.5 million deaths attributed to TB annually worldwide. The global dissemination of drug resistance across Mycobacterium tuberculosis (Mtb) strains, causative of TB, resulted in an estimated 450 000 cases of drug-resistant (DR) TB in 2021. Dysregulated immune responses have been observed in patients with multidrug resistant (MDR) TB, but the effects of drug resistance acquisition and impact on host immunity remain obscure. In this review, we compile studies that span aspects of altered host-pathogen interactions and highlight research that explores how drug resistance and immunity might intersect. Understanding the immune processes differentially induced during DR TB would aid the development of rational therapeutics and vaccines for patients with MDR TB.
Collapse
Affiliation(s)
- Suhas Bobba
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Shabaana A Khader
- Department of Microbiology, University of Chicago, Chicago, IL 60637, USA.
| |
Collapse
|
7
|
Keller MR, Dörr T. Bacterial metabolism and susceptibility to cell wall-active antibiotics. Adv Microb Physiol 2023; 83:181-219. [PMID: 37507159 PMCID: PMC11024984 DOI: 10.1016/bs.ampbs.2023.04.002] [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: 07/30/2023]
Abstract
Bacterial infections are increasingly resistant to antimicrobial therapy. Intense research focus has thus been placed on identifying the mechanisms that bacteria use to resist killing or growth inhibition by antibiotics and the ways in which bacteria share these traits with one another. This work has led to the advancement of new drugs, combination therapy regimens, and a deeper appreciation for the adaptability seen in microorganisms. However, while the primary mechanisms of action of most antibiotics are well understood, the more subtle contributions of bacterial metabolic state to repairing or preventing damage caused by antimicrobials (thereby promoting survival) are still understudied. Here, we review a modern viewpoint on a classical system: examining bacterial metabolism's connection to antibiotic susceptibility. We dive into the relationship between metabolism and antibiotic efficacy through the lens of growth rate, energy state, resource allocation, and the infection environment, focusing on cell wall-active antibiotics.
Collapse
Affiliation(s)
- Megan Renee Keller
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, United States
| | - Tobias Dörr
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, United States; Department of Microbiology, Cornell University, Ithaca, NY, United States; Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, NY, United States.
| |
Collapse
|
8
|
Mycobacterium tuberculosis Requires the Outer Membrane Lipid Phthiocerol Dimycocerosate for Starvation-Induced Antibiotic Tolerance. mSystems 2023; 8:e0069922. [PMID: 36598240 PMCID: PMC9948706 DOI: 10.1128/msystems.00699-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Tolerance of Mycobacterium tuberculosis to antibiotics contributes to the long duration of tuberculosis (TB) treatment and the emergence of drug-resistant strains. M. tuberculosis drug tolerance is induced by nutrient restriction, but the genetic determinants that promote antibiotic tolerance triggered by nutrient limitation have not been comprehensively identified. Here, we show that M. tuberculosis requires production of the outer membrane lipid phthiocerol dimycocerosate (PDIM) to tolerate antibiotics under nutrient-limited conditions. We developed an arrayed transposon (Tn) mutant library in M. tuberculosis Erdman and used orthogonal pooling and transposon sequencing (Tn-seq) to map the locations of individual mutants in the library. We screened a subset of the library (~1,000 mutants) by Tn-seq and identified 32 and 102 Tn mutants with altered tolerance to antibiotics under stationary-phase and phosphate-starved conditions, respectively. Two mutants recovered from the arrayed library, ppgK::Tn and clpS::Tn, showed increased susceptibility to two different drug combinations under both nutrient-limited conditions, but their phenotypes were not complemented by the Tn-disrupted gene. Whole-genome sequencing revealed single nucleotide polymorphisms in both the ppgK::Tn and clpS::Tn mutants that prevented PDIM production. Complementation of the clpS::Tn ppsD Q291* mutant with ppsD restored PDIM production and antibiotic tolerance, demonstrating that loss of PDIM sensitized M. tuberculosis to antibiotics. Our data suggest that drugs targeting production of PDIM, a critical M. tuberculosis virulence determinant, have the potential to enhance the efficacy of existing antibiotics, thereby shortening TB treatment and limiting development of drug resistance. IMPORTANCE Mycobacterium tuberculosis causes 10 million cases of active TB disease and over 1 million deaths worldwide each year. TB treatment is complex, requiring at least 6 months of therapy with a combination of antibiotics. One factor that contributes to the length of TB treatment is M. tuberculosis phenotypic antibiotic tolerance, which allows the bacteria to survive prolonged drug exposure even in the absence of genetic mutations causing drug resistance. Here, we report a genetic screen to identify M. tuberculosis genes that promote drug tolerance during nutrient starvation. Our study revealed the outer membrane lipid phthiocerol dimycocerosate (PDIM) as a key determinant of M. tuberculosis antibiotic tolerance triggered by nutrient starvation. Our study implicates PDIM synthesis as a potential target for development of new TB drugs that would sensitize M. tuberculosis to existing antibiotics to shorten TB treatment.
Collapse
|
9
|
Kiani BH, Alonso MN, Weathers PJ, Shell SS. Artemisia afra and Artemisia annua Extracts Have Bactericidal Activity against Mycobacterium tuberculosis in Physiologically Relevant Carbon Sources and Hypoxia. Pathogens 2023; 12:227. [PMID: 36839499 PMCID: PMC9963027 DOI: 10.3390/pathogens12020227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 01/25/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
Mycobacterium tuberculosis (Mtb) is a deadly pathogen and causative agent of human tuberculosis, causing ~1.5 million deaths every year. The increasing drug resistance of this pathogen necessitates novel and improved treatment strategies. A crucial aspect of the host-pathogen interaction is bacterial nutrition. In this study, Artemisia annua and Artemisia afra dichloromethane extracts were tested for bactericidal activity against Mtb strain mc26230 under hypoxia and various infection-associated carbon sources (glycerol, glucose, and cholesterol). Both extracts showed significant bactericidal activity against Mtb, regardless of carbon source. Based on killing curves, A. afra showed the most consistent bactericidal activity against Mtb for all tested carbon sources, whereas A. annua showed the highest bactericidal activity in 7H9 minimal media with glycerol. Both extracts retained their bactericidal activity against Mtb under hypoxic conditions. Further investigations are required to determine the mechanism of action of these extracts and identify their active constituent compounds.
Collapse
Affiliation(s)
| | | | | | - Scarlet S. Shell
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA 01609, USA
| |
Collapse
|
10
|
Brody SI, Buonomo JA, Orimoloye MO, Jia Z, Sharma S, Brown CD, Baughn AD, Aldrich CC. A Nucleophilic Activity-Based Probe Enables Profiling of PLP-Dependent Enzymes. Chembiochem 2023; 24:e202200669. [PMID: 36652345 DOI: 10.1002/cbic.202200669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/14/2023] [Accepted: 01/18/2023] [Indexed: 01/19/2023]
Abstract
PLP-dependent enzymes represent an important class of highly "druggable" enzymes that perform a wide array of critical reactions to support all organisms. Inhibition of individual members of this family of enzymes has been validated as a therapeutic target for pathologies ranging from infection with Mycobacterium tuberculosis to epilepsy. Given the broad nature of the activities within this family of enzymes, we envisioned a universally acting probe to characterize existing and putative members of the family that also includes the necessary chemical moieties to enable activity-based protein profiling experiments. Hence, we developed a probe that contains an N-hydroxyalanine warhead that acts as a covalent inhibitor of PLP-dependent enzymes, a linear diazirine for UV crosslinking, and an alkyne moiety to enable enrichment of crosslinked proteins. Our molecule was used to study PLP-dependent enzymes in vitro as well as look at whole-cell lysates of M. tuberculosis and assess inhibitory activity. The probe was able to enrich and identify LysA, a PLP-dependent enzyme crucial for lysine biosynthesis, through mass spectrometry. Overall, our study shows the utility of this trifunctional first-generation probe. We anticipate further optimization of probes for PLP-dependent enzymes will enable the characterization of rationally designed covalent inhibitors of PLP-dependent enzymes, which will expedite the preclinical characterization of these important therapeutic targets.
Collapse
Affiliation(s)
- Scott I Brody
- Department of Medicinal Chemistry, University of Minnesota-Twin Cities, 308 Harvard Street SE, Minneapolis, MN 55455, USA
| | - Joseph A Buonomo
- Department of Medicinal Chemistry, University of Minnesota-Twin Cities, 308 Harvard Street SE, Minneapolis, MN 55455, USA
| | - Moyosore O Orimoloye
- Department of Medicinal Chemistry, University of Minnesota-Twin Cities, 308 Harvard Street SE, Minneapolis, MN 55455, USA
| | - Ziyi Jia
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Sachin Sharma
- Department of Medicinal Chemistry, University of Minnesota-Twin Cities, 308 Harvard Street SE, Minneapolis, MN 55455, USA
| | - Christopher D Brown
- Department of Medicinal Chemistry, University of Minnesota-Twin Cities, 308 Harvard Street SE, Minneapolis, MN 55455, USA
| | - Anthony D Baughn
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Courtney C Aldrich
- Department of Medicinal Chemistry, University of Minnesota-Twin Cities, 308 Harvard Street SE, Minneapolis, MN 55455, USA
| |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
Yan MY, Zheng D, Li SS, Ding XY, Wang CL, Guo XP, Zhan L, Jin Q, Yang J, Sun YC. Application of combined CRISPR screening for genetic and chemical-genetic interaction profiling in Mycobacterium tuberculosis. SCIENCE ADVANCES 2022; 8:eadd5907. [PMID: 36417506 PMCID: PMC9683719 DOI: 10.1126/sciadv.add5907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 10/05/2022] [Indexed: 05/30/2023]
Abstract
CRISPR screening, including CRISPR interference (CRISPRi) and CRISPR-knockout (CRISPR-KO) screening, has become a powerful technology in the genetic screening of eukaryotes. In contrast with eukaryotes, CRISPR-KO screening has not yet been applied to functional genomics studies in bacteria. Here, we constructed genome-scale CRISPR-KO and also CRISPRi libraries in Mycobacterium tuberculosis (Mtb). We first examined these libraries to identify genes essential for Mtb viability. Subsequent screening identified dozens of genes associated with resistance/susceptibility to the antitubercular drug bedaquiline (BDQ). Genetic and chemical validation of the screening results suggested that it provided a valuable resource to investigate mechanisms of action underlying the effects of BDQ and to identify chemical-genetic synergies that can be used to optimize tuberculosis therapy. In summary, our results demonstrate the potential for efficient genome-wide CRISPR-KO screening in bacteria and establish a combined CRISPR screening approach for high-throughput investigation of genetic and chemical-genetic interactions in Mtb.
Collapse
Affiliation(s)
- Mei-Yi Yan
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for Tuberculosis Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China
| | - Dandan Zheng
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for Tuberculosis Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China
| | - Si-Shang Li
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for Tuberculosis Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China
| | - Xin-Yuan Ding
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for Tuberculosis Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China
| | - Chun-Liang Wang
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for Tuberculosis Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China
| | - Xiao-Peng Guo
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for Tuberculosis Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China
| | - Lingjun Zhan
- NHC Key Laboratory of Human Disease Comparative Medicine, Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China
| | - Qi Jin
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for Tuberculosis Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China
| | - Jian Yang
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for Tuberculosis Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China
| | - Yi-Cheng Sun
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for Tuberculosis Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China
| |
Collapse
|
13
|
Poulton NC, Rock JM. Unraveling the mechanisms of intrinsic drug resistance in Mycobacterium tuberculosis. Front Cell Infect Microbiol 2022; 12:997283. [PMID: 36325467 PMCID: PMC9618640 DOI: 10.3389/fcimb.2022.997283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/30/2022] [Indexed: 02/03/2023] Open
Abstract
Tuberculosis (TB) is among the most difficult infections to treat, requiring several months of multidrug therapy to produce a durable cure. The reasons necessitating long treatment times are complex and multifactorial. However, one major difficulty of treating TB is the resistance of the infecting bacterium, Mycobacterium tuberculosis (Mtb), to many distinct classes of antimicrobials. This review will focus on the major gaps in our understanding of intrinsic drug resistance in Mtb and how functional and chemical-genetics can help close those gaps. A better understanding of intrinsic drug resistance will help lay the foundation for strategies to disarm and circumvent these mechanisms to develop more potent antitubercular therapies.
Collapse
|
14
|
Roubert C, Fontaine E, Upton AM. “Upcycling” known molecules and targets for drug-resistant TB. Front Cell Infect Microbiol 2022; 12:1029044. [PMID: 36275029 PMCID: PMC9582839 DOI: 10.3389/fcimb.2022.1029044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 09/21/2022] [Indexed: 11/13/2022] Open
Abstract
Despite reinvigorated efforts in Tuberculosis (TB) drug discovery over the past 20 years, relatively few new drugs and candidates have emerged with clear utility against drug resistant TB. Over the same period, significant technological advances and learnings around target value have taken place. This has offered opportunities to re-assess the potential for optimization of previously discovered chemical matter against Mycobacterium tuberculosis (M.tb) and for reconsideration of clinically validated targets encumbered by drug resistance. A re-assessment of discarded compounds and programs from the “golden age of antibiotics” has yielded new scaffolds and targets against TB and uncovered classes, for example beta-lactams, with previously unappreciated utility for TB. Leveraging validated classes and targets has also met with success: booster technologies and efforts to thwart efflux have improved the potential of ethionamide and spectinomycin classes. Multiple programs to rescue high value targets while avoiding cross-resistance are making progress. These attempts to make the most of known classes, drugs and targets complement efforts to discover new chemical matter against novel targets, enhancing the chances of success of discovering effective novel regimens against drug-resistant TB.
Collapse
|
15
|
Poulton NC, Azadian ZA, DeJesus MA, Rock JM. Mutations in rv0678 Confer Low-Level Resistance to Benzothiazinone DprE1 Inhibitors in Mycobacterium tuberculosis. Antimicrob Agents Chemother 2022; 66:e0090422. [PMID: 35920665 PMCID: PMC9487612 DOI: 10.1128/aac.00904-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Tuberculosis (TB) is the leading cause of death from any bacterial infection, causing 1.5 million deaths worldwide each year. Due to the emergence of drug-resistant strains of Mycobacterium tuberculosis (Mtb) there have been significant efforts aimed at developing novel drugs to treat TB. One promising drug target in Mtb is the arabinogalactan biosynthetic enzyme DprE1, and there have been over a dozen unique chemical scaffolds identified which inhibit the activity of this protein. Among the most promising lead compounds are the benzothiazinones BTZ043 and PBTZ169, both of which are currently in or have completed phase IIa clinical trials. Due to the potential clinical utility of these drugs, we sought to identify potential synergistic interactions and new mechanisms of resistance using a genome-scale CRISPRi chemical-genetic screen with PBTZ169. We found that knockdown of rv0678, the negative regulator of the mmpS5/L5 drug efflux pump, confers resistance to PBTZ169. Mutations in rv0678 are the most common form of resistance to bedaquiline and there is already abundant evidence of these mutations emerging in bedaquiline-treated patients. We confirmed that rv0678 mutations from clinical isolates confer low level cross-resistance to BTZ043 and PBTZ169. While it is yet unclear whether rv0678 mutations would render benzothiazinones ineffective in treating TB, these results highlight the importance of monitoring for clinically prevalent rv0678 mutations during ongoing BTZ043 and PBTZ169 clinical trials.
Collapse
Affiliation(s)
- Nicholas C. Poulton
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, New York, USA
| | - Zachary A. Azadian
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, New York, USA
| | - Michael A. DeJesus
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, New York, USA
| | - Jeremy M. Rock
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, New York, USA
| |
Collapse
|
16
|
Tomasi FG, Rubin EJ. Failing upwards: Genetics-based strategies to improve antibiotic discovery and efficacy in Mycobacterium tuberculosis. Front Cell Infect Microbiol 2022; 12:932556. [PMID: 36189351 PMCID: PMC9519881 DOI: 10.3389/fcimb.2022.932556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 08/17/2022] [Indexed: 11/18/2022] Open
Abstract
Therapeutic advances in the 20th century significantly reduced tuberculosis (TB) mortality. Nonetheless, TB still poses a massive global health challenge with significant annual morbidity and mortality that has been amplified during the COVID-19 pandemic. Unlike most common bacterial infectious diseases, successful TB treatment requires months-long regimens, which complicates the ability to treat all cases quickly and effectively. Improving TB chemotherapy by reducing treatment duration and optimizing combinations of drugs is an important step to reducing relapse. In this review, we outline the limitations of current multidrug regimens against TB and have reviewed the genetic tools available to improve the identification of drug targets. The rational design of regimens that sterilize diverse phenotypic subpopulations will maximize bacterial killing while minimizing both treatment duration and infection relapse. Importantly, the TB field currently has all the necessary genetic and analytical tools to screen for and prioritize drug targets in vitro based on the vulnerability of essential and non-essential genes in the Mtb genome and to translate these findings in in vivo models. Combining genetic methods with chemical screens offers a formidable strategy to redefine the preclinical design of TB therapy by identifying powerful new targets altogether, as well as targets that lend new efficacy to existing drugs.
Collapse
|
17
|
McNeil MB, Cheung CY, Waller NJE, Adolph C, Chapman CL, Seeto NEJ, Jowsey W, Li Z, Hameed HMA, Zhang T, Cook GM. Uncovering interactions between mycobacterial respiratory complexes to target drug-resistant Mycobacterium tuberculosis. Front Cell Infect Microbiol 2022; 12:980844. [PMID: 36093195 PMCID: PMC9461714 DOI: 10.3389/fcimb.2022.980844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 08/03/2022] [Indexed: 11/24/2022] Open
Abstract
Mycobacterium tuberculosis remains a leading cause of infectious disease morbidity and mortality for which new drug combination therapies are needed. Mycobacterial bioenergetics has emerged as a promising space for the development of novel therapeutics. Further to this, unique combinations of respiratory inhibitors have been shown to have synergistic or synthetic lethal interactions, suggesting that combinations of bioenergetic inhibitors could drastically shorten treatment times. Realizing the full potential of this unique target space requires an understanding of which combinations of respiratory complexes, when inhibited, have the strongest interactions and potential in a clinical setting. In this review, we discuss (i) chemical-interaction, (ii) genetic-interaction and (iii) chemical-genetic interaction studies to explore the consequences of inhibiting multiple mycobacterial respiratory components. We provide potential mechanisms to describe the basis for the strongest interactions. Finally, whilst we place an emphasis on interactions that occur with existing bioenergetic inhibitors, by highlighting interactions that occur with alternative respiratory components we envision that this information will provide a rational to further explore alternative proteins as potential drug targets and as part of unique drug combinations.
Collapse
Affiliation(s)
- Matthew B. McNeil
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Maurice Wilkins, Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
- *Correspondence: Matthew B. McNeil, ; Gregory M. Cook,
| | - Chen-Yi Cheung
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Natalie J. E. Waller
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Cara Adolph
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Cassandra L. Chapman
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Noon E. J. Seeto
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - William Jowsey
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Zhengqiu Li
- School of Pharmacy, Jinan University, Guangzhou, China
| | - H. M. Adnan Hameed
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health (GIBH), Chinese Academy of Sciences (CAS), Guangzhou, China
- China-New Zealand Joint Laboratory of Biomedicine and Health, Guangzhou Institutes of Biomedicine and Health (GIBH), Chinese Academy of Sciences (CAS), Guangzhou, China
- Guangdong-Hong Kong-Macau Joint Laboratory of Respiratory Infectious Diseases, Guangzhou, China
- University of Chinese Academy of Sciences (UCAS), Beijing, China
| | - Tianyu Zhang
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health (GIBH), Chinese Academy of Sciences (CAS), Guangzhou, China
- China-New Zealand Joint Laboratory of Biomedicine and Health, Guangzhou Institutes of Biomedicine and Health (GIBH), Chinese Academy of Sciences (CAS), Guangzhou, China
- Guangdong-Hong Kong-Macau Joint Laboratory of Respiratory Infectious Diseases, Guangzhou, China
- University of Chinese Academy of Sciences (UCAS), Beijing, China
| | - Gregory M. Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Maurice Wilkins, Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
- *Correspondence: Matthew B. McNeil, ; Gregory M. Cook,
| |
Collapse
|
18
|
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.
Collapse
Affiliation(s)
| | | | | | | | - Christina L. Stallings
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO, United States
| |
Collapse
|
19
|
Impaired Succinate Oxidation Prevents Growth and Influences Drug Susceptibility in Mycobacterium tuberculosis. mBio 2022; 13:e0167222. [PMID: 35856639 PMCID: PMC9426501 DOI: 10.1128/mbio.01672-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Succinate is a major focal point in mycobacterial metabolism and respiration, serving as both an intermediate of the tricarboxylic acid (TCA) cycle and a direct electron donor for the respiratory chain. Mycobacterium tuberculosis encodes multiple enzymes predicted to be capable of catalyzing the oxidation of succinate to fumarate, including two different succinate dehydrogenases (Sdh1 and Sdh2) and a separate fumarate reductase (Frd) with possible bidirectional behavior. Previous attempts to investigate the essentiality of succinate oxidation in M. tuberculosis have relied on the use of single-gene deletion mutants, raising the possibility that the remaining enzymes could catalyze succinate oxidation in the absence of the other. To address this, we report on the use of mycobacterial CRISPR interference (CRISPRi) to construct single, double, and triple transcriptional knockdowns of sdhA1, sdhA2, and frdA in M. tuberculosis. We show that the simultaneous knockdown of sdhA1 and sdhA2 is required to prevent succinate oxidation and overcome the functional redundancy within these enzymes. Succinate oxidation was demonstrated to be essential for the optimal growth of M. tuberculosis, with the combined knockdown of sdhA1 and sdhA2 significantly impairing the activity of the respiratory chain and preventing growth on a range of carbon sources. Moreover, impaired succinate oxidation was shown to influence the activity of cell wall-targeting antibiotics and bioenergetic inhibitors against M. tuberculosis. Together, these data provide fundamental insights into mycobacterial physiology, energy metabolism, and antimicrobial susceptibility. IMPORTANCE New drugs are urgently required to combat the tuberculosis epidemic that claims 1.5 million lives annually. Inhibitors of mycobacterial energy metabolism have shown significant promise clinically; however, further advancing this nascent target space requires a more fundamental understanding of the respiratory enzymes and pathways used by Mycobacterium tuberculosis. Succinate is a major focal point in mycobacterial metabolism and respiration; yet, the essentiality of succinate oxidation and the consequences of inhibiting this process are poorly defined. In this study, we demonstrate that impaired succinate oxidation prevents the optimal growth of M. tuberculosis on a range of carbon sources and significantly reduces the activity of the electron transport chain. Moreover, we show that impaired succinate oxidation both positively and negatively influences the activity of a variety of antituberculosis drugs. Combined, these findings provide fundamental insights into mycobacterial physiology and drug susceptibility that will be useful in the continued development of bioenergetic inhibitors.
Collapse
|