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Painter H, Larsen SE, Williams BD, Abdelaal HFM, Baldwin SL, Fletcher HA, Fiore-Gartland A, Coler RN. Backtranslation of human RNA biosignatures of tuberculosis disease risk into the preclinical pipeline is condition dependent. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.21.600067. [PMID: 38948876 PMCID: PMC11212953 DOI: 10.1101/2024.06.21.600067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
It is not clear whether human progression to active tuberculosis disease (TB) risk signatures are viable endpoint criteria for evaluations of treatments in clinical or preclinical development. TB is the deadliest infectious disease globally and more efficacious vaccines are needed to reduce this mortality. However, the immune correlates of protection for either preventing infection with Mycobacterium tuberculosis or preventing TB disease have yet to be completely defined, making the advancement of candidate vaccines through the pipeline slow, costly, and fraught with risk. Human-derived correlate of risk (COR) gene signatures, which identify an individual's risk to progressing to active TB disease, provide an opportunity for evaluating new therapies for TB with clear and defined endpoints. Though prospective clinical trials with longitudinal sampling are prohibitively expensive, characterization of COR gene signatures is practical with preclinical models. Using a 3Rs (Replacement, Reduction and Refinement) approach we reanalyzed heterogeneous publicly available transcriptional datasets to determine whether a specific set of COR signatures are viable endpoints in the preclinical pipeline. We selected RISK6, Sweeney3 and BATF2 human-derived blood-based RNA biosignatures because they require relatively few genes to assign a score and have been carefully evaluated across several clinical cohorts. Excitingly, these data provide proof-of-concept that human COR signatures seem to have high fidelity across several tissue types in the preclinical TB model pipeline and show best performance when the model most closely reflected human infection or disease conditions. Human-derived COR signatures offer an opportunity for high-throughput preclinical endpoint criteria of vaccine and drug therapy evaluations. One Sentence Summary Human-derived biosignatures of tuberculosis disease progression were evaluated for their predictive fidelity across preclinical species and derived tissues using available public data sets.
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Chen Y, MacGilvary NJ, Tan S. Mycobacterium tuberculosis response to cholesterol is integrated with environmental pH and potassium levels via a lipid metabolism regulator. PLoS Genet 2024; 20:e1011143. [PMID: 38266039 PMCID: PMC10843139 DOI: 10.1371/journal.pgen.1011143] [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: 11/09/2023] [Revised: 02/05/2024] [Accepted: 01/19/2024] [Indexed: 01/26/2024] Open
Abstract
Successful colonization of the host requires Mycobacterium tuberculosis (Mtb) to sense and respond coordinately to disparate environmental cues during infection and adapt its physiology. However, how Mtb response to environmental cues and the availability of key carbon sources may be integrated is poorly understood. Here, by exploiting a reporter-based genetic screen, we have unexpectedly found that overexpression of transcription factors involved in Mtb lipid metabolism altered the dampening effect of low environmental potassium concentrations ([K+]) on the pH response of Mtb. Cholesterol is a major carbon source for Mtb during infection, and transcriptional analyses revealed that Mtb response to acidic pH was augmented in the presence of cholesterol and vice versa. Strikingly, deletion of the putative lipid regulator mce3R had little effect on Mtb transcriptional response to acidic pH or cholesterol individually, but resulted specifically in loss of cholesterol response augmentation in the simultaneous presence of acidic pH. Similarly, while mce3R deletion had little effect on Mtb response to low environmental [K+] alone, augmentation of the low [K+] response by the simultaneous presence of cholesterol was lost in the mutant. Finally, a mce3R deletion mutant was attenuated for growth in foamy macrophages and for colonization in a murine infection model that recapitulates caseous necrotic lesions and the presence of foamy macrophages. These findings reveal the critical coordination between Mtb response to environmental cues and cholesterol, a vital carbon source, and establishes Mce3R as a transcription factor that crucially serves to integrate these signals.
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Affiliation(s)
- Yue Chen
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Nathan J. MacGilvary
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Current affiliation: Department of Molecular, Cell, and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
| | - Shumin Tan
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
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Wynn EA, Dide-Agossou C, Reichlen M, Rossmassler K, Al Mubarak R, Reid JJ, Tabor ST, Born SEM, Ransom MR, Davidson RM, Walton KN, Benoit JB, Hoppers A, Loy DE, Bauman AA, Massoudi LM, Dolganov G, Strong M, Nahid P, Voskuil MI, Robertson GT, Moore CM, Walter ND. Transcriptional adaptation of Mycobacterium tuberculosis that survives prolonged multi-drug treatment in mice. mBio 2023; 14:e0236323. [PMID: 37905920 PMCID: PMC10746229 DOI: 10.1128/mbio.02363-23] [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: 09/13/2023] [Accepted: 09/25/2023] [Indexed: 11/02/2023] Open
Abstract
To address the ongoing global tuberculosis crisis, there is a need for shorter, more effective treatments. A major reason why tuberculosis requires prolonged treatment is that, following a short initial phase of rapid killing, the residual Mycobacterium tuberculosis withstands drug killing. Because existing methods lack sensitivity to quantify low-abundance mycobacterial RNA in drug-treated animals, cellular adaptations of drug-exposed bacterial phenotypes in vivo remain poorly understood. Here, we used a novel RNA-seq method called SEARCH-TB to elucidate the Mycobacterium tuberculosis transcriptome in mice treated for up to 28 days with standard doses of isoniazid, rifampin, pyrazinamide, and ethambutol. We compared murine results with in vitro SEARCH-TB results during exposure to the same regimen. Treatment suppressed genes associated with growth, transcription, translation, synthesis of rRNA proteins, and immunogenic secretory peptides. Bacteria that survived prolonged treatment appeared to transition from ATP-maximizing respiration toward lower-efficiency pathways and showed modification and recycling of cell wall components, large-scale regulatory reprogramming, and reconfiguration of efflux pump expression. Although the pre-treatment in vivo and in vitro transcriptomes differed profoundly, genes differentially expressed following treatment in vivo and in vitro were similar, with differences likely attributable to immunity and drug pharmacokinetics in mice. These results reveal cellular adaptations of Mycobacterium tuberculosis that withstand prolonged drug exposure in vivo, demonstrating proof of concept that SEARCH-TB is a highly granular pharmacodynamic readout. The surprising finding that differential expression is concordant in vivo and in vitro suggests that insights from transcriptional analyses in vitro may translate to the mouse. IMPORTANCE A major reason that curing tuberculosis requires prolonged treatment is that drug exposure changes bacterial phenotypes. The physiologic adaptations of Mycobacterium tuberculosis that survive drug exposure in vivo have been obscure due to low sensitivity of existing methods in drug-treated animals. Using the novel SEARCH-TB RNA-seq platform, we elucidated Mycobacterium tuberculosis phenotypes in mice treated for with the global standard 4-drug regimen and compared them with the effect of the same regimen in vitro. This first view of the transcriptome of the minority Mycobacterium tuberculosis population that withstands treatment in vivo reveals adaptation of a broad range of cellular processes, including a shift in metabolism and cell wall modification. Surprisingly, the change in gene expression induced by treatment in vivo and in vitro was largely similar. This apparent "portability" from in vitro to the mouse provides important new context for in vitro transcriptional analyses that may support early preclinical drug evaluation.
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Affiliation(s)
- Elizabeth A. Wynn
- Rocky Mountain Regional VA Medical Center, Aurora, Colorado, USA
- Department of Biostatistics and Informatics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
- Consortium for Applied Microbial Metrics, Aurora, Colorado, USA
| | - Christian Dide-Agossou
- Rocky Mountain Regional VA Medical Center, Aurora, Colorado, USA
- Consortium for Applied Microbial Metrics, Aurora, Colorado, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Matthew Reichlen
- Consortium for Applied Microbial Metrics, Aurora, Colorado, USA
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Karen Rossmassler
- Rocky Mountain Regional VA Medical Center, Aurora, Colorado, USA
- Consortium for Applied Microbial Metrics, Aurora, Colorado, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Reem Al Mubarak
- Rocky Mountain Regional VA Medical Center, Aurora, Colorado, USA
- Consortium for Applied Microbial Metrics, Aurora, Colorado, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Justin J. Reid
- Rocky Mountain Regional VA Medical Center, Aurora, Colorado, USA
- Consortium for Applied Microbial Metrics, Aurora, Colorado, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Samuel T. Tabor
- Rocky Mountain Regional VA Medical Center, Aurora, Colorado, USA
- Consortium for Applied Microbial Metrics, Aurora, Colorado, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Sarah E. M. Born
- Consortium for Applied Microbial Metrics, Aurora, Colorado, USA
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Monica R. Ransom
- Division of Hematology, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Rebecca M. Davidson
- Center for Genes, Environment and Health, National Jewish Health, Denver, Colorado, USA
| | - Kendra N. Walton
- Center for Genes, Environment and Health, National Jewish Health, Denver, Colorado, USA
| | - Jeanne B. Benoit
- Center for Genes, Environment and Health, National Jewish Health, Denver, Colorado, USA
| | - Amanda Hoppers
- Center for Genes, Environment and Health, National Jewish Health, Denver, Colorado, USA
| | - Dorothy E. Loy
- Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Allison A. Bauman
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Lisa M. Massoudi
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Gregory Dolganov
- Division of Infectious Diseases and Geographic Medicine, Stanford University, Palo Alto, California, USA
| | - Michael Strong
- Center for Genes, Environment and Health, National Jewish Health, Denver, Colorado, USA
| | - Payam Nahid
- Consortium for Applied Microbial Metrics, Aurora, Colorado, USA
- Division of Pulmonary and Critical Care Medicine, University of California San Francisco, San Francisco, California, USA
- UCSF Center for Tuberculosis, University of California San Francisco, San Francisco, California, USA
| | - Martin I. Voskuil
- Consortium for Applied Microbial Metrics, Aurora, Colorado, USA
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Gregory T. Robertson
- Consortium for Applied Microbial Metrics, Aurora, Colorado, USA
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Camille M. Moore
- Department of Biostatistics and Informatics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
- Consortium for Applied Microbial Metrics, Aurora, Colorado, USA
- Center for Genes, Environment and Health, National Jewish Health, Denver, Colorado, USA
| | - Nicholas D. Walter
- Rocky Mountain Regional VA Medical Center, Aurora, Colorado, USA
- Consortium for Applied Microbial Metrics, Aurora, Colorado, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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4
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Chen Y, MacGilvary NJ, Tan S. Mycobacterium tuberculosis response to cholesterol is integrated with environmental pH and potassium levels via a lipid utilization regulator. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.22.554309. [PMID: 37662244 PMCID: PMC10473576 DOI: 10.1101/2023.08.22.554309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
How bacterial response to environmental cues and nutritional sources may be integrated in enabling host colonization is poorly understood. Exploiting a reporter-based screen, we discovered that overexpression of Mycobacterium tuberculosis (Mtb) lipid utilization regulators altered Mtb acidic pH response dampening by low environmental potassium (K+). Transcriptional analyses unveiled amplification of Mtb response to acidic pH in the presence of cholesterol, a major carbon source for Mtb during infection, and vice versa. Strikingly, deletion of the putative lipid regulator mce3R resulted in loss of augmentation of (i) cholesterol response at acidic pH, and (ii) low [K+] response by cholesterol, with minimal effect on Mtb response to each signal individually. Finally, the ∆mce3R mutant was attenuated for colonization in a murine model that recapitulates lesions with lipid-rich foamy macrophages. These findings reveal critical coordination between bacterial response to environmental and nutritional cues, and establish Mce3R as a crucial integrator of this process.
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Affiliation(s)
- Yue Chen
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
| | - Nathan J. MacGilvary
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
| | - Shumin Tan
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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5
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Simcox BS, Tomlinson BR, Shaw LN, Rohde KH. Mycobacterium abscessus DosRS two-component system controls a species-specific regulon required for adaptation to hypoxia. Front Cell Infect Microbiol 2023; 13:1144210. [PMID: 36968107 PMCID: PMC10034137 DOI: 10.3389/fcimb.2023.1144210] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 02/15/2023] [Indexed: 03/12/2023] Open
Abstract
Mycobacterium abscessus (Mab), an emerging opportunistic pathogen, predominantly infects individuals with underlying pulmonary diseases such as cystic fibrosis (CF). Current treatment outcomes for Mab infections are poor due to Mab's inherent antibiotic resistance and unique host interactions that promote phenotypic tolerance and hinder drug access. The hypoxic, mucus-laden airways in the CF lung and antimicrobial phagosome within macrophages represent hostile niches Mab must overcome via alterations in gene expression for survival. Regulatory mechanisms important for the adaptation and long-term persistence of Mab within the host are poorly understood, warranting further genetic and transcriptomics study of this emerging pathogen. DosRS Mab , a two-component signaling system (TCS), is one proposed mechanism utilized to subvert host defenses and counteract environmental stress such as hypoxia. The homologous TCS of Mycobacterium tuberculosis (Mtb), DosRS Mtb , is known to induce a ~50 gene regulon in response to hypoxia, carbon monoxide (CO) and nitric oxide (NO) in vitro and in vivo. Previously, a small DosR Mab regulon was predicted using bioinformatics based on DosR Mtb motifs however, the role and regulon of DosRS Mab in Mab pathogenesis have yet to be characterized in depth. To address this knowledge gap, our lab generated a Mab dosRS knockout strain (MabΔdosRS) to investigate differential gene expression, and phenotype in an in vitro hypoxia model of dormancy. qRT-PCR and lux reporter assays demonstrate Mab_dosR and 6 predicted downstream genes are induced in hypoxia. In addition, RNAseq revealed induction of a much larger hypoxia response comprised of >1000 genes, including 127 differentially expressed genes in a dosRS mutant strain. Deletion of DosRS Mab led to attenuated growth under low oxygen conditions, a shift in morphotype from smooth to rough, and down-regulation of 216 genes. This study provides the first look at the global transcriptomic response of Mab to low oxygen conditions encountered in the airways of CF patients and within macrophage phagosomes. Our data also demonstrate the importance of DosRS Mab for adaptation of Mab to hypoxia, highlighting a distinct regulon (compared to Mtb) that is significantly larger than previously described, including both genes conserved across mycobacteria as well as Mab-specific genes.
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Affiliation(s)
- Breven S. Simcox
- Division of Immunology and Pathogenesis, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
| | - Brooke R. Tomlinson
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL, United States
| | - Lindsey N. Shaw
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL, United States
| | - Kyle H. Rohde
- Division of Immunology and Pathogenesis, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
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6
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Wynn EA, Dide-Agossou C, Reichlen M, Rossmassler K, Al Mubarak R, Reid JJ, Tabor ST, Born SEM, Ransom MR, Davidson RM, Walton KN, Benoit JB, Hoppers A, Bauman AA, Massoudi LM, Dolganov G, Nahid P, Voskuil MI, Robertson GT, Moore CM, Walter ND. Transcriptional adaptation of drug-tolerant Mycobacterium tuberculosis in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.06.531356. [PMID: 36945388 PMCID: PMC10028792 DOI: 10.1101/2023.03.06.531356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
Transcriptome evaluation of Mycobacterium tuberculosis in the lungs of laboratory animals during long-term treatment has been limited by extremely low abundance of bacterial mRNA relative to eukaryotic RNA. Here we report a targeted amplification RNA sequencing method called SEARCH-TB. After confirming that SEARCH-TB recapitulates conventional RNA-seq in vitro, we applied SEARCH-TB to Mycobacterium tuberculosis-infected BALB/c mice treated for up to 28 days with the global standard isoniazid, rifampin, pyrazinamide, and ethambutol regimen. We compared results in mice with 8-day exposure to the same regimen in vitro. After treatment of mice for 28 days, SEARCH-TB suggested broad suppression of genes associated with bacterial growth, transcription, translation, synthesis of rRNA proteins and immunogenic secretory peptides. Adaptation of drug-stressed Mycobacterium tuberculosis appeared to include a metabolic transition from ATP-maximizing respiration towards lower-efficiency pathways, modification and recycling of cell wall components, large-scale regulatory reprogramming, and reconfiguration of efflux pumps expression. Despite markedly different expression at pre-treatment baseline, murine and in vitro samples had broadly similar transcriptional change during treatment. The differences observed likely indicate the importance of immunity and pharmacokinetics in the mouse. By elucidating the long-term effect of tuberculosis treatment on bacterial cellular processes in vivo, SEARCH-TB represents a highly granular pharmacodynamic monitoring tool with potential to enhance evaluation of new regimens and thereby accelerate progress towards a new generation of more effective tuberculosis treatment.
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Affiliation(s)
- Elizabeth A Wynn
- Rocky Mountain Regional VA Medical Center, Aurora, CO, USA
- Department of Biostatistics and Informatics, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
- Consortium for Applied Microbial Metrics, Aurora, CO, USA
| | - Christian Dide-Agossou
- Rocky Mountain Regional VA Medical Center, Aurora, CO, USA
- Consortium for Applied Microbial Metrics, Aurora, CO, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Matthew Reichlen
- Consortium for Applied Microbial Metrics, Aurora, CO, USA
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Karen Rossmassler
- Rocky Mountain Regional VA Medical Center, Aurora, CO, USA
- Consortium for Applied Microbial Metrics, Aurora, CO, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Reem Al Mubarak
- Rocky Mountain Regional VA Medical Center, Aurora, CO, USA
- Consortium for Applied Microbial Metrics, Aurora, CO, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Justin J Reid
- Rocky Mountain Regional VA Medical Center, Aurora, CO, USA
- Consortium for Applied Microbial Metrics, Aurora, CO, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Samuel T Tabor
- Rocky Mountain Regional VA Medical Center, Aurora, CO, USA
- Consortium for Applied Microbial Metrics, Aurora, CO, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Sarah E M Born
- Consortium for Applied Microbial Metrics, Aurora, CO, USA
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Monica R Ransom
- Division of Hematology, Department of Medicine, University of Colorado School of Medicine, Aurora, CO, USA
| | - Rebecca M Davidson
- Center for Genes, Environment and Health, National Jewish Health, Denver, CO, USA
| | - Kendra N Walton
- Center for Genes, Environment and Health, National Jewish Health, Denver, CO, USA
| | - Jeanne B Benoit
- Center for Genes, Environment and Health, National Jewish Health, Denver, CO, USA
| | - Amanda Hoppers
- Center for Genes, Environment and Health, National Jewish Health, Denver, CO, USA
| | - Allison A Bauman
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Lisa M Massoudi
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Gregory Dolganov
- Division of Infectious Diseases and Geographic Medicine, Stanford University, Palo Alto, CA, USA
| | - Payam Nahid
- Consortium for Applied Microbial Metrics, Aurora, CO, USA
- Division of Pulmonary and Critical Care Medicine, University of California San Francisco, CA, USA
- UCSF Center for Tuberculosis, University of California, San Francisco, CA, USA
| | - Martin I Voskuil
- Consortium for Applied Microbial Metrics, Aurora, CO, USA
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Gregory T Robertson
- Consortium for Applied Microbial Metrics, Aurora, CO, USA
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Camille M Moore
- Department of Biostatistics and Informatics, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
- Consortium for Applied Microbial Metrics, Aurora, CO, USA
- Center for Genes, Environment and Health, National Jewish Health, Denver, CO, USA
| | - Nicholas D Walter
- Rocky Mountain Regional VA Medical Center, Aurora, CO, USA
- Consortium for Applied Microbial Metrics, Aurora, CO, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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7
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Inflammation-mediated tissue damage in pulmonary tuberculosis and host-directed therapeutic strategies. Semin Immunol 2023; 65:101672. [PMID: 36469987 DOI: 10.1016/j.smim.2022.101672] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 11/04/2022] [Accepted: 11/08/2022] [Indexed: 12/04/2022]
Abstract
Treatment of tuberculosis (TB) involves the administration of anti-mycobacterial drugs for several months. The emergence of drug-resistant strains of Mycobacterium tuberculosis (Mtb, the causative agent) together with increased disease severity in people with co-morbidities such as diabetes mellitus and HIV have hampered efforts to reduce case fatality. In severe disease, TB pathology is largely attributable to over-exuberant host immune responses targeted at controlling bacterial replication. Non-resolving inflammation driven by host pro-inflammatory mediators in response to high bacterial load leads to pulmonary pathology including cavitation and fibrosis. The need to improve clinical outcomes and reduce treatment times has led to a two-pronged approach involving the development of novel antimicrobials as well as host-directed therapies (HDT) that favourably modulate immune responses to Mtb. HDT strategies incorporate aspects of immune modulation aimed at downregulating non-productive inflammatory responses and augmenting antimicrobial effector mechanisms to minimise pulmonary pathology and accelerate symptom resolution. HDT in combination with existing antimycobacterial agents offers a potentially promising strategy to improve the long-term outcome for TB patients. In this review, we describe components of the host immune response that contribute to inflammation and tissue damage in pulmonary TB, including cytokines, matrix metalloproteinases, lipid mediators, and neutrophil extracellular traps. We then proceed to review HDT directed at these pathways.
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Donegan RK, Fu Y, Copeland J, Idga S, Brown G, Hale OF, Mitra A, Yang H, Dailey HA, Niederweis M, Jain P, Reddi AR. Exogenously Scavenged and Endogenously Synthesized Heme Are Differentially Utilized by Mycobacterium tuberculosis. Microbiol Spectr 2022; 10:e0360422. [PMID: 36169423 PMCID: PMC9604157 DOI: 10.1128/spectrum.03604-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 09/13/2022] [Indexed: 01/12/2023] Open
Abstract
Heme is both an essential cofactor and an abundant source of nutritional iron for the human pathogen Mycobacterium tuberculosis. While heme is required for M. tuberculosis survival and virulence, it is also potentially cytotoxic. Since M. tuberculosis can both synthesize and take up heme, the de novo synthesis of heme and its acquisition from the host may need to be coordinated in order to mitigate heme toxicity. However, the mechanisms employed by M. tuberculosis to regulate heme uptake, synthesis, and bioavailability are poorly understood. By integrating ratiometric heme sensors with mycobacterial genetics, cell biology, and biochemistry, we determined that de novo-synthesized heme is more bioavailable than exogenously scavenged heme, and heme availability signals the downregulation of heme biosynthetic enzyme gene expression. Ablation of heme synthesis does not result in the upregulation of known heme import proteins. Moreover, we found that de novo heme synthesis is critical for survival from macrophage assault. Altogether, our data suggest that mycobacteria utilize heme from endogenous and exogenous sources differently and that targeting heme synthesis may be an effective therapeutic strategy to treat mycobacterial infections. IMPORTANCE Mycobacterium tuberculosis infects ~25% of the world's population and causes tuberculosis (TB), the second leading cause of death from infectious disease. Heme is an essential metabolite for M. tuberculosis, and targeting the unique heme biosynthetic pathway of M. tuberculosis could serve as an effective therapeutic strategy. However, since M. tuberculosis can both synthesize and scavenge heme, it was unclear if inhibiting heme synthesis alone could serve as a viable approach to suppress M. tuberculosis growth and virulence. The importance of this work lies in the development and application of genetically encoded fluorescent heme sensors to probe bioavailable heme in M. tuberculosis and the discovery that endogenously synthesized heme is more bioavailable than exogenously scavenged heme. Moreover, it was found that heme synthesis protected M. tuberculosis from macrophage killing, and bioavailable heme in M. tuberculosis is diminished during macrophage infection. Altogether, these findings suggest that targeting M. tuberculosis heme synthesis is an effective approach to combat M. tuberculosis infections.
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Affiliation(s)
- Rebecca K. Donegan
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
- Department of Chemistry, Barnard College, New York, New York, USA
| | - Yibo Fu
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Jacqueline Copeland
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Stanzin Idga
- Department of Pathology, Laura and Isaac Perlmutter Cancer Center, New York University Grossman School of Medicine, New York, New York, USA
| | - Gabriel Brown
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Owen F. Hale
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Avishek Mitra
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Hui Yang
- Department of Neurology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Harry A. Dailey
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Michael Niederweis
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Paras Jain
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
- Cell Therapy and Cell Engineering Laboratory, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Amit R. Reddi
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- Parker Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia, USA
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9
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Gautam US, Asrican R, Sempowski GD. Targeted dose delivery of Mycobacterium tuberculosis in mice using silicon antifoaming agent via aerosol exposure system. PLoS One 2022; 17:e0276130. [PMID: 36228009 PMCID: PMC9560519 DOI: 10.1371/journal.pone.0276130] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/29/2022] [Indexed: 11/09/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) is an intracellular pathogen that forms aggregates (clumps) on solid agar plates and in liquid media. Detergents such as Tween 80/Tyloxapol are considered the gold standard to disrupt clump formation in Mtb cultures. The presence of detergent, however, may generate foam and hinder Mtb aerosolization thus requiring addition of an antifoam agent for optimal Mtb aerosol-based procedures. Aerosol inhalation can be technically challenging, in particular to achieve a reproducible inhaled target dose. In this study, the impact of an antifoam, the silicon antifoaming agent (SAF), on Mtb aerosolization and whole-body mouse aerosol infection was investigated. A comparative study using SAF in a liquid suspension containing Mycobacterium bovis BCG (M. bovis BCG) or Mtb H37Rv did not cause any adverse effect on bacterial viability. Incorporation of SAF during mycobacteria inhalation procedures revealed that aerosolized mycobacterial strains were maintained under controlled environmental conditions such as humidity, temperature, pressure, and airflow inside the aerosol chamber. In addition, environmental factors and spray factors were not affected by the presence of SAF in mycobacterial cultures during aerosolization. Spray factor was significantly less during aerosol procedures with a low-input dose of mycobacteria in comparison to high-dose, as predicted. The mycobacterial load recovered in the biosampler (AGI) was ~2–3 logs lower than nebulizer or input bacterial load. A consistent Mtb bacillary load determined in mouse lungs indicates that SAF does not affect mycobacteria aerosolization during the aerosol generation process. These data confirmed that 1) SAF prevents formation of excessive foam during aerosolization, 2) SAF had no negative impact on mycobacterial viability within aerosol droplets, 3) Mtb droplets within aerosol-generated particles are well within the range required for reaching and depositing deep into lung tissue, and 4) SAF had no negative impact on achieving a target dose in mice exposed to Mtb aerosol.
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Affiliation(s)
- Uma Shankar Gautam
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
- * E-mail: (USG); (GDS)
| | - Rosemarie Asrican
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Gregory D. Sempowski
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
- Departments of Medicine and Pathology, Duke University School of Medicine, Durham, North Carolina, United States of America
- * E-mail: (USG); (GDS)
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10
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Giacalone D, Yap RE, Ecker AMV, Tan S. PrrA modulates Mycobacterium tuberculosis response to multiple environmental cues and is critically regulated by serine/threonine protein kinases. PLoS Genet 2022; 18:e1010331. [PMID: 35913986 PMCID: PMC9371303 DOI: 10.1371/journal.pgen.1010331] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 08/11/2022] [Accepted: 07/08/2022] [Indexed: 12/04/2022] Open
Abstract
The ability of Mycobacterium tuberculosis (Mtb) to adapt to its surrounding environment is critical for the bacterium to successfully colonize its host. Transcriptional changes are a vital mechanism by which Mtb responds to key environmental signals experienced, such as pH, chloride (Cl-), nitric oxide (NO), and hypoxia. However, much remains unknown regarding how Mtb coordinates its response to the disparate signals seen during infection. Utilizing a transcription factor (TF) overexpression plasmid library in combination with a pH/Cl--responsive luciferase reporter, we identified the essential TF, PrrA, part of the PrrAB two-component system, as a TF involved in modulation of Mtb response to pH and Cl-. Further studies revealed that PrrA also affected Mtb response to NO and hypoxia, with prrA overexpression dampening induction of NO and hypoxia-responsive genes. PrrA is phosphorylated not just by its cognate sensor histidine kinase PrrB, but also by serine/threonine protein kinases (STPKs) at a second distinct site. Strikingly, a STPK-phosphoablative PrrA variant was significantly dampened in its response to NO versus wild type Mtb, disrupted in its ability to adaptively enter a non-replicative state upon extended NO exposure, and attenuated for in vivo colonization. Together, our results reveal PrrA as an important regulator of Mtb response to multiple environmental signals, and uncover a critical role of STPK regulation of PrrA in its function. Vital to successful host colonization by Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, is the bacterium’s ability to respond and adapt to changes in its local environment during infection. Here, we discover that the essential transcription factor PrrA, part of the PrrAB two-component system (TCS), modulates Mtb response to four important environmental cues encountered within the host: pH, chloride, nitric oxide, and hypoxia. PrrA acts as a rheostat, adjusting the amplitude of Mtb gene expression changes upon bacterial exposure to each of the four environmental signals. Further, we reveal a critical impact of serine/threonine protein kinases (STPKs) on PrrA function, with prevention of STPK phosphorylation of PrrA disrupting adaptive response of Mtb to growth-inhibiting cues and attenuating the bacterium’s ability to colonize its host. Our work uncovers PrrA as a regulator with broad impact across environmental signals, and highlights how two regulatory systems, TCSs and STPKs, critically interact in coordinating Mtb response to environmental cues.
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Affiliation(s)
- David Giacalone
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Graduate Program in Molecular Microbiology, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America
| | - Rochelle E. Yap
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Alwyn M. V. Ecker
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Shumin Tan
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Graduate Program in Molecular Microbiology, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America
- * E-mail:
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11
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Bucşan AN, Veatch A, Singh DK, Akter S, Golden NA, Kirkpatrick M, Threeton B, Moodley C, Ahmed M, Doyle LA, Russell-Lodrigue K, Norton EB, Didier PJ, Roy CJ, Abramovitch RB, Mehra S, Khader SA, Kaushal D. Response to Hypoxia and the Ensuing Dysregulation of Inflammation Impacts Mycobacterium tuberculosis Pathogenicity. Am J Respir Crit Care Med 2022; 206:94-104. [PMID: 35412961 PMCID: PMC9718519 DOI: 10.1164/rccm.202112-2747oc] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Rationale: Different Mycobacterium tuberculosis (Mtb) strains exhibit variable degrees of virulence in humans and animal models. Differing stress response strategies used by different strains of Mtb could influence virulence. Objectives: We compared the virulence of two strains of Mtb with use in animal model research: CDC1551 and Erdman. Methods: Rhesus macaques, which develop human-like tuberculosis attributes and pathology, were infected with a high dose of either strain via aerosol, and virulence was compared by bacterial burden and pathology. Measurements and Main Results: Infection with Erdman resulted in significantly shorter times to euthanasia and higher bacterial burdens and greater systemic inflammation and lung pathology relative to those infected with CDC1551. Macaques infected with Erdman also exhibited significantly higher early inflammatory myeloid cell influx to the lung, greater macrophage and T cell activity, and higher expression of lung remodeling (extracellular matrix) genes, consistent with greater pathology. Expression of NOTCH4 (neurogenic locus notch homolog 4) signaling, which is induced in response to hypoxia and promotes undifferentiated cellular state, was also higher in Erdman-infected lungs. The granulomas generated by Erdman, and not CDC1551, infection appeared to have larger regions of necrosis, which is strongly associated with hypoxia. To better understand the mechanisms of differential hypoxia induction by these strains, we subjected both to hypoxia in vitro. Erdman induced higher concentrations of DosR regulon relative to CDC1551. The DosR regulon is the global regulator of response to hypoxia in Mtb and critical for its persistence in granulomas. Conclusions: Our results show that the response to hypoxia is a critical mediator of virulence determination in Mtb, with potential impacts on bacillary persistence, reactivation, and efficiency of therapeutics.
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Affiliation(s)
- Allison N. Bucşan
- Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, Louisiana
| | - Ashley Veatch
- Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, Louisiana
| | - Dhiraj K. Singh
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, Texas
| | - Sadia Akter
- Department of Molecular Microbiology, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - Nadia A. Golden
- Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, Louisiana
| | - Melanie Kirkpatrick
- Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, Louisiana
| | - Breanna Threeton
- Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, Louisiana
| | - Chivonne Moodley
- Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, Louisiana
| | - Mushtaq Ahmed
- Department of Molecular Microbiology, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - Lara A. Doyle
- Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, Louisiana
| | - Kasi Russell-Lodrigue
- Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, Louisiana
| | - Elizabeth B. Norton
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, Louisiana; and
| | - Peter J. Didier
- Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, Louisiana
| | - Chad J. Roy
- Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, Louisiana;,Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, Texas
| | - Robert B. Abramovitch
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan
| | - Smriti Mehra
- Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, Louisiana;,Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, Texas
| | - Shabaana A. Khader
- Department of Molecular Microbiology, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - Deepak Kaushal
- Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, Louisiana;,Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, Texas
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12
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Sevalkar RR, Glasgow JN, Pettinati M, Marti MA, Reddy VP, Basu S, Alipour E, Kim-Shapiro DB, Estrin DA, Lancaster JR, Steyn AJC. Mycobacterium tuberculosis DosS binds H 2S through its Fe 3+ heme iron to regulate the DosR dormancy regulon. Redox Biol 2022; 52:102316. [PMID: 35489241 PMCID: PMC9062744 DOI: 10.1016/j.redox.2022.102316] [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: 02/28/2022] [Revised: 04/06/2022] [Accepted: 04/16/2022] [Indexed: 01/14/2023] Open
Abstract
Mycobacterium tuberculosis (Mtb) senses and responds to host-derived gasotransmitters NO and CO via heme-containing sensor kinases DosS and DosT and the response regulator DosR. Hydrogen sulfide (H2S) is an important signaling molecule in mammals, but its role in Mtb physiology is unclear. We have previously shown that exogenous H2S can modulate expression of genes in the Dos dormancy regulon via an unknown mechanism(s). Here, we test the hypothesis that Mtb senses and responds to H2S via the DosS/T/R system. Using UV-Vis and EPR spectroscopy, we show that H2S binds directly to the ferric (Fe3+) heme of DosS (KDapp = 5.30 μM) but not the ferrous (Fe2+) form. No interaction with DosT(Fe2+-O2) was detected. We found that the binding of sulfide can slowly reduce the DosS heme iron to the ferrous form. Steered Molecular Dynamics simulations show that H2S, and not the charged HS- species, can enter the DosS heme pocket. We also show that H2S increases DosS autokinase activity and subsequent phosphorylation of DosR, and H2S-mediated increases in Dos regulon gene expression is lost in Mtb lacking DosS. Finally, we demonstrate that physiological levels of H2S in macrophages can induce DosR regulon genes via DosS. Overall, these data reveal a novel mechanism whereby Mtb senses and responds to a third host gasotransmitter, H2S, via DosS(Fe3+). These findings highlight the remarkable plasticity of DosS and establish a new paradigm for how bacteria can sense multiple gasotransmitters through a single heme sensor kinase.
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Affiliation(s)
- Ritesh R Sevalkar
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Joel N Glasgow
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Martín Pettinati
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE), Buenos Aires, Argentina
| | - Marcelo A Marti
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Química Biológica (IQUIBICEN), Buenos Aires, Argentina
| | - Vineel P Reddy
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Swati Basu
- Department of Physics, Wake Forest University, Winston-Salem, NC, USA
| | - Elmira Alipour
- Department of Physics, Wake Forest University, Winston-Salem, NC, USA
| | | | - Dario A Estrin
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE), Buenos Aires, Argentina
| | - Jack R Lancaster
- Department of Pharmacology & Chemical Biology, Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Adrie J C Steyn
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA; Centers for AIDS Research and Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA; Africa Health Research Institute, University of KwaZulu-Natal, Durban, South Africa.
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13
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Belardinelli JM, Verma D, Li W, Avanzi C, Wiersma CJ, Williams JT, Johnson BK, Zimmerman M, Whittel N, Angala B, Wang H, Jones V, Dartois V, de Moura VCN, Gonzalez-Juarrero M, Pearce C, Schenkel AR, Malcolm KC, Nick JA, Charman SA, Wells TNC, Podell BK, Vennerstrom JL, Ordway DJ, Abramovitch RB, Jackson M. Therapeutic efficacy of antimalarial drugs targeting DosRS signaling in Mycobacterium abscessus. Sci Transl Med 2022; 14:eabj3860. [PMID: 35196022 DOI: 10.1126/scitranslmed.abj3860] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A search for alternative Mycobacterium abscessus treatments led to our interest in the two-component regulator DosRS, which, in Mycobacterium tuberculosis, is required for the bacterium to establish a state of nonreplicating, drug-tolerant persistence in response to a variety of host stresses. We show here that the genetic disruption of dosRS impairs the adaptation of M. abscessus to hypoxia, resulting in decreased bacterial survival after oxygen depletion, reduced tolerance to a number of antibiotics in vitro and in vivo, and the inhibition of biofilm formation. We determined that three antimalarial drugs or drug candidates, artemisinin, OZ277, and OZ439, can target DosS-mediated hypoxic signaling in M. abscessus and recapitulate the phenotypic effects of genetically disrupting dosS. OZ439 displayed bactericidal activity comparable to standard-of-care antibiotics in chronically infected mice, in addition to potentiating the activity of antibiotics used in combination. The identification of antimalarial drugs as potent inhibitors and adjunct inhibitors of M. abscessus in vivo offers repurposing opportunities that could have an immediate impact in the clinic.
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Affiliation(s)
- Juan Manuel Belardinelli
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Deepshikha Verma
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Wei Li
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Charlotte Avanzi
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Crystal J Wiersma
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - John T Williams
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | | | - Matthew Zimmerman
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, USA
| | - Nicholas Whittel
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Bhanupriya Angala
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Han Wang
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, USA
| | - Victoria Jones
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Véronique Dartois
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, USA
| | - Vinicius C N de Moura
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Mercedes Gonzalez-Juarrero
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Camron Pearce
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Alan R Schenkel
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Kenneth C Malcolm
- Department of Medicine, National Jewish Health, Denver, CO, USA.,Department of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
| | - Jerry A Nick
- Department of Medicine, National Jewish Health, Denver, CO, USA.,Department of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
| | - Susan A Charman
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | | | - Brendan K Podell
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | | | - Diane J Ordway
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Robert B Abramovitch
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
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14
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King A, Blackledge MS. Evaluation of small molecule kinase inhibitors as novel antimicrobial and antibiofilm agents. Chem Biol Drug Des 2021; 98:1038-1064. [PMID: 34581492 PMCID: PMC8616828 DOI: 10.1111/cbdd.13962] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/24/2021] [Accepted: 09/15/2021] [Indexed: 12/25/2022]
Abstract
Antibiotic resistance is a global and pressing concern. Our current therapeutic arsenal is increasingly limited as bacteria are developing resistance at a rate that far outpaces our ability to create new treatments. Novel approaches to treating and curing bacterial infections are urgently needed. Bacterial kinases have been increasingly explored as novel drug targets and are poised for development into novel therapeutic agents to combat bacterial infections. This review describes several general classes of bacterial kinases that play important roles in bacterial growth, antibiotic resistance, and biofilm formation. General features of these kinase classes are discussed and areas of particular interest for the development of inhibitors will be highlighted. Small molecule kinase inhibitors are described and organized by phenotypic effect, spotlighting particularly interesting inhibitors with novel functions and potential therapeutic benefit. Finally, we provide our perspective on the future of bacterial kinase inhibition as a viable strategy to combat bacterial infections and overcome the pressures of increasing antibiotic resistance.
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Affiliation(s)
- Ashley King
- Department of Chemistry, High Point University, One University Parkway, High Point, NC 27268
| | - Meghan S. Blackledge
- Department of Chemistry, High Point University, One University Parkway, High Point, NC 27268
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15
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Lavin RC, Johnson C, Ahn YM, Kremiller KM, Sherwood M, Patel JS, Pan Y, Russo R, MacGilvary NJ, Giacalone D, Kevorkian YL, Zimmerman MD, Glickman JF, Freundlich JS, Tan S. Targeting Mycobacterium tuberculosis response to environmental cues for the development of effective antitubercular drugs. PLoS Biol 2021; 19:e3001355. [PMID: 34319985 PMCID: PMC8351955 DOI: 10.1371/journal.pbio.3001355] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 08/09/2021] [Accepted: 07/08/2021] [Indexed: 11/28/2022] Open
Abstract
Sensing and response to environmental cues, such as pH and chloride (Cl−), is critical in enabling Mycobacterium tuberculosis (Mtb) colonization of its host. Utilizing a fluorescent reporter Mtb strain in a chemical screen, we have identified compounds that dysregulate Mtb response to high Cl− levels, with a subset of the hits also inhibiting Mtb growth in host macrophages. Structure–activity relationship studies on the hit compound “C6,” or 2-(4-((2-(ethylthio)pyrimidin-5-yl)methyl)piperazin-1-yl)benzo[d]oxazole, demonstrated a correlation between compound perturbation of Mtb Cl− response and inhibition of bacterial growth in macrophages. C6 accumulated in both bacterial and host cells, and inhibited Mtb growth in cholesterol media, but not in rich media. Subsequent examination of the Cl− response of Mtb revealed an intriguing link with bacterial growth in cholesterol, with increased transcription of several Cl−-responsive genes in the simultaneous presence of cholesterol and high external Cl− concentration, versus transcript levels observed during exposure to high external Cl− concentration alone. Strikingly, oral administration of C6 was able to inhibit Mtb growth in vivo in a C3HeB/FeJ murine infection model. Our work illustrates how Mtb response to environmental cues can intersect with its metabolism and be exploited in antitubercular drug discovery. Responding to environmental cues such as pH and chloride is critical in enabling Mycobacterium tuberculosis to colonize its host. A chemical screen using an M. tuberculosis strain bearing a fluorescent reporter identifies a compound that perturbs the bacterial response to chloride and inhibits its growth in a murine infection model.
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Affiliation(s)
- Richard C. Lavin
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Graduate Program in Molecular Microbiology, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America
| | - Calvin Johnson
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Yong-Mo Ahn
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University–New Jersey Medical School, Newark, New Jersey, United States of America
| | - Kyle M. Kremiller
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University–New Jersey Medical School, Newark, New Jersey, United States of America
| | - Matthew Sherwood
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University–New Jersey Medical School, Newark, New Jersey, United States of America
| | - Jimmy S. Patel
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University–New Jersey Medical School, Newark, New Jersey, United States of America
| | - Yan Pan
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, United States of America
| | - Riccardo Russo
- Division of Infectious Disease, Department of Medicine and the Ruy V. Lourenco Center for the Study of Emerging and Re-emerging Pathogens, Rutgers University–New Jersey Medical School, Newark, New Jersey, United States of America
| | - Nathan J. MacGilvary
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - David Giacalone
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Graduate Program in Molecular Microbiology, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America
| | - Yuzo L. Kevorkian
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Graduate Program in Molecular Microbiology, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America
| | - Matthew D. Zimmerman
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, United States of America
| | - J. Fraser Glickman
- High-Throughput and Spectroscopy Resource Center, The Rockefeller University, New York, New York, United States of America
| | - Joel S. Freundlich
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers University–New Jersey Medical School, Newark, New Jersey, United States of America
- Division of Infectious Disease, Department of Medicine and the Ruy V. Lourenco Center for the Study of Emerging and Re-emerging Pathogens, Rutgers University–New Jersey Medical School, Newark, New Jersey, United States of America
| | - Shumin Tan
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Graduate Program in Molecular Microbiology, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America
- * E-mail:
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16
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Abstract
Multidrug-resistant tuberculosis (MDR-TB) is an infectious disease caused by Mycobacterium tuberculosis which is resistant to at least isoniazid and rifampicin. This disease is a worldwide threat and complicates the control of tuberculosis (TB). Long treatment duration, a combination of several drugs, and the adverse effects of these drugs are the factors that play a role in the poor outcomes of MDR-TB patients. There have been many studies with repurposed drugs to improve MDR-TB outcomes, including clofazimine. Clofazimine recently moved from group 5 to group B of drugs that are used to treat MDR-TB. This drug belongs to the riminophenazine class, which has lipophilic characteristics and was previously discovered to treat TB and approved for leprosy. This review discusses the role of clofazimine as a treatment component in patients with MDR-TB, and the drug’s properties. In addition, we discuss the efficacy, safety, and tolerability of clofazimine for treating MDR-TB. This study concludes that the clofazimine-containing regimen has better efficacy compared with the standard one and is also well-tolerated. Clofazimine has the potential to shorten the duration of MDR-TB treatment.
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17
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Ganatra SR, Bucşan AN, Alvarez X, Kumar S, Chatterjee A, Quezada M, Fish A, Singh DK, Singh B, Sharan R, Lee TH, Shanmugasundaram U, Velu V, Khader SA, Mehra S, Rengarajan J, Kaushal D. Antiretroviral therapy does not reduce tuberculosis reactivation in a tuberculosis-HIV coinfection model. J Clin Invest 2020; 130:5171-5179. [PMID: 32544085 PMCID: PMC7524506 DOI: 10.1172/jci136502] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 06/04/2020] [Indexed: 12/12/2022] Open
Abstract
While the advent of combination antiretroviral therapy (ART) has significantly improved survival, tuberculosis (TB) remains the leading cause of death in the HIV-infected population. We used Mycobacterium tuberculosis/simian immunodeficiency virus-coinfected (M. tuberculosis/SIV-coinfected) macaques to model M. tuberculosis/HIV coinfection and study the impact of ART on TB reactivation due to HIV infection. Although ART significantly reduced viral loads and increased CD4+ T cell counts in blood and bronchoalveolar lavage (BAL) samples, it did not reduce the relative risk of SIV-induced TB reactivation in ART-treated macaques in the early phase of treatment. CD4+ T cells were poorly restored specifically in the lung interstitium, despite their significant restoration in the alveolar compartment of the lung as well as in the periphery. IDO1 induction in myeloid cells in the inducible bronchus-associated lymphoid tissue (iBALT) likely contributed to dysregulated T cell homing and impaired lung immunity. Thus, although ART was indispensable for controlling viral replication, restoring CD4+ T cells, and preventing opportunistic infection, it appeared inadequate in reversing the clinical signs of TB reactivation during the relatively short duration of ART administered in this study. This finding warrants the modeling of concurrent treatment of TB and HIV to potentially reduce the risk of reactivation of TB due to HIV to inform treatment strategies in patients with M. tuberculosis/HIV coinfection.
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Affiliation(s)
- Shashank R. Ganatra
- Southwest National Primate Research Center (SNPRC), Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Allison N. Bucşan
- Tulane National Primate Research Center (TNPRC), Covington, Louisiana, USA
| | - Xavier Alvarez
- Southwest National Primate Research Center (SNPRC), Texas Biomedical Research Institute, San Antonio, Texas, USA
- Tulane National Primate Research Center (TNPRC), Covington, Louisiana, USA
| | - Shyamesh Kumar
- Southwest National Primate Research Center (SNPRC), Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Ayan Chatterjee
- Southwest National Primate Research Center (SNPRC), Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Melanie Quezada
- Emory Vaccine Center and
- Yerkes National Primate Research Center (YNPRC), Emory University School of Medicine, Atlanta, Georgia, USA
| | - Abigail Fish
- Southwest National Primate Research Center (SNPRC), Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Dhiraj K. Singh
- Southwest National Primate Research Center (SNPRC), Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Bindu Singh
- Southwest National Primate Research Center (SNPRC), Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Riti Sharan
- Southwest National Primate Research Center (SNPRC), Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Tae-Hyung Lee
- Southwest National Primate Research Center (SNPRC), Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Uma Shanmugasundaram
- Emory Vaccine Center and
- Yerkes National Primate Research Center (YNPRC), Emory University School of Medicine, Atlanta, Georgia, USA
| | - Vijayakumar Velu
- Emory Vaccine Center and
- Yerkes National Primate Research Center (YNPRC), Emory University School of Medicine, Atlanta, Georgia, USA
| | - Shabaana A. Khader
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Smriti Mehra
- Tulane National Primate Research Center (TNPRC), Covington, Louisiana, USA
| | - Jyothi Rengarajan
- Emory Vaccine Center and
- Yerkes National Primate Research Center (YNPRC), Emory University School of Medicine, Atlanta, Georgia, USA
- Department of Medicine, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Deepak Kaushal
- Southwest National Primate Research Center (SNPRC), Texas Biomedical Research Institute, San Antonio, Texas, USA
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18
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Sharan R, Bucşan AN, Ganatra S, Paiardini M, Mohan M, Mehra S, Khader SA, Kaushal D. Chronic Immune Activation in TB/HIV Co-infection. Trends Microbiol 2020; 28:619-632. [PMID: 32417227 PMCID: PMC7390597 DOI: 10.1016/j.tim.2020.03.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/03/2020] [Accepted: 03/25/2020] [Indexed: 12/27/2022]
Abstract
HIV co-infection is the most critical risk factor for the reactivation of latent tuberculosis (TB) infection (LTBI). While CD4+ T cell depletion has been considered the major cause of HIV-induced reactivation of LTBI, recent work in macaques co-infected with Mycobacterium tuberculosis (Mtb)/simian immunodeficiency virus (SIV) suggests that cytopathic effects of SIV resulting in chronic immune activation and dysregulation of T cell homeostasis correlate with reactivation of LTBI. This review builds on compelling data that the reactivation of LTBI during HIV co-infection is likely to be driven by the events of HIV replication and therefore highlights the need to have optimum translational interventions directed at reactivation due to co-infection.
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Affiliation(s)
- Riti Sharan
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Allison N Bucşan
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Shashank Ganatra
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Mirko Paiardini
- Yerkes National Primate Research Center, Emory University School of Medicine, Atlanta, GA 30329, USA
| | - Mahesh Mohan
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Smriti Mehra
- Tulane National Primate Research Center, Tulane University School of Medicine, Covington, LA 70433, USA
| | - Shabaana A Khader
- Department of Molecular Microbiology, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Deepak Kaushal
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX 78227, USA.
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19
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Mavi PS, Singh S, Kumar A. Reductive Stress: New Insights in Physiology and Drug Tolerance of Mycobacterium. Antioxid Redox Signal 2020; 32:1348-1366. [PMID: 31621379 DOI: 10.1089/ars.2019.7867] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Significance:Mycobacterium tuberculosis (Mtb) encounters reductive stress during its infection cycle. Notably, host-generated protective responses, such as acidic pH inside phagosomes and lysosomes, exposure to glutathione in alveolar hypophase (i.e., a thin liquid lining consisting of surfactant and proteins in the alveolus), and hypoxic environments inside granulomas are associated with the accumulation of reduced cofactors, such as nicotinamide adenine dinucleotide (reduced form), nicotinamide adenine dinucleotide phosphate, flavin adenine dinucleotide (reduced form), and nonprotein thiols (e.g., mycothiol), leading to reductive stress in Mtb cells. Dissipation of this reductive stress is important for survival of the bacterium. If reductive stress is not dissipated, it leads to generation of reactive oxygen species, which may be fatal for the cells. Recent Advances: This review focuses on mechanisms utilized by mycobacteria to sense and respond to reductive stress. Importantly, exposure of Mtb cells to reductive stress leads to growth inhibition, altered metabolism, modulation of virulence, and drug tolerance. Mtb is equipped with thiol buffering systems of mycothiol and ergothioneine to protect itself from various redox stresses. These systems are complemented by thioredoxin and thioredoxin reductase (TR) systems for maintaining cellular redox homeostasis. A diverse array of sensors is used by Mycobacterium for monitoring its intracellular redox status. Upon sensing reductive stress, Mtb uses a flexible and robust metabolic system for its dissipation. Branched electron transport chain allows Mycobacterium to function with different terminal electron acceptors and modulate proton motive force to fulfill energy requirements under diverse scenarios. Interestingly, Mtb utilizes variations in the tricarboxylic cycle and a number of dehydrogenases to dissipate reductive stress. Upon prolonged exposure to reductive stress, Mtb utilizes biosynthesis of storage and virulence lipids as a dissipative mechanism. Critical Issues: The mechanisms utilized by Mycobacterium for sensing and tackling reductive stress are not well characterized. Future Directions: The precise role of thiol buffering and TR systems in neutralizing reductive stress is not well defined. Genetic systems that respond to metabolic reductive stress and thiol reductive stress need to be mapped. Genetic screens could aid in identification of such systems. Given that management of reductive stress is critical for both actively replicating and persister mycobacteria, an improved understanding of the mechanisms used by mycobacteria for dissipation of reductive stress may lead to identification of vulnerable choke points that could be targeted for killing Mtb in vivo.
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Affiliation(s)
- Parminder Singh Mavi
- Institute of Microbial Technology, Council of Scientific and Industrial Research, Chandigarh, India
| | - Shweta Singh
- Institute of Microbial Technology, Council of Scientific and Industrial Research, Chandigarh, India
| | - Ashwani Kumar
- Institute of Microbial Technology, Council of Scientific and Industrial Research, Chandigarh, India.,Academy of Scientific and Innovative Research, Ghaziabad, India
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20
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Abstract
Progress against tuberculosis (TB) requires faster-acting drugs. Mycobacterium tuberculosis (Mtb) is the leading cause of death by an infectious disease and its treatment is challenging and lengthy. Mtb is remarkably successful, in part, due to its ability to become dormant in response to host immune pressures. The DosRST two-component regulatory system is induced by hypoxia, nitric oxide and carbon monoxide and remodels Mtb physiology to promote nonreplicating persistence (NRP). NRP bacteria are thought to play a role in the long course of TB treatment. Therefore, inhibitors of DosRST-dependent adaptation may function to kill this reservoir of persisters and potentially shorten therapy. This review examines the function of DosRST, newly discovered compounds that inhibit DosRST signaling and considers future development of DosRST inhibitors as adjunct therapies.
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21
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Zheng H, Williams JT, Aleiwi B, Ellsworth E, Abramovitch RB. Inhibiting Mycobacterium tuberculosis DosRST Signaling by Targeting Response Regulator DNA Binding and Sensor Kinase Heme. ACS Chem Biol 2020; 15:52-62. [PMID: 31556993 PMCID: PMC6970277 DOI: 10.1021/acschembio.8b00849] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
![]()
Mycobacterium
tuberculosis (Mtb) possesses a two-component
regulatory system, DosRST, that enables Mtb to sense host immune cues
and establish a state of nonreplicating persistence (NRP). NRP bacteria
are tolerant to several antimycobacterial drugs in vitro and are thought to play a role in the long course of tuberculosis
therapy. Previously, we reported the discovery of six novel chemical
inhibitors of DosRST, named HC101A–106A, from a whole cell,
reporter-based phenotypic high throughput screen. Here, we report
functional and mechanism of action studies of HC104A and HC106A. RNaseq
transcriptional profiling shows that the compounds downregulate genes
of the DosRST regulon. Both compounds reduce hypoxia-induced triacylglycerol
synthesis by ∼50%. HC106A inhibits Mtb survival during hypoxia-induced
NRP; however, HC104A did not inhibit survival during NRP. An electrophoretic
mobility assay shows that HC104A inhibits DosR DNA binding in a dose-dependent
manner, indicating that HC104A may function by directly targeting
DosR. In contrast, UV–visible spectroscopy studies suggest
HC106A directly targets the sensor kinase heme, via a mechanism that
is distinct from the oxidation and alkylation of heme previously observed
with artemisinin (HC101A). Synergistic interactions were observed
when DosRST inhibitors were examined in pairwise combinations with
the strongest potentiation observed between artemisinin paired with
HC102A, HC103A, or HC106A. Our data collectively show that the DosRST
pathway can be inhibited by multiple distinct mechanisms.
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22
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Gautam US, Mehra S, Kumari P, Alvarez X, Niu T, Tyagi JS, Kaushal D. Mycobacterium tuberculosis sensor kinase DosS modulates the autophagosome in a DosR-independent manner. Commun Biol 2019; 2:349. [PMID: 31552302 PMCID: PMC6754383 DOI: 10.1038/s42003-019-0594-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Accepted: 09/03/2019] [Indexed: 01/03/2023] Open
Abstract
Dormancy is a key characteristic of the intracellular life-cycle of Mtb. The importance of sensor kinase DosS in mycobacteria are attributed in part to our current findings that DosS is required for both persistence and full virulence of Mtb. Here we show that DosS is also required for optimal replication in macrophages and involved in the suppression of TNF-α and autophagy pathways. Silencing of these pathways during the infection process restored full virulence in MtbΔdosS mutant. Notably, a mutant of the response regulator DosR did not exhibit the attenuation in macrophages, suggesting that DosS can function independently of DosR. We identified four DosS targets in Mtb genome; Rv0440, Rv2859c, Rv0994, and Rv0260c. These genes encode functions related to hypoxia adaptation, which are not directly controlled by DosR, e.g., protein recycling and chaperoning, biosynthesis of molybdenum cofactor and nitrogen metabolism. Our results strongly suggest a DosR-independent role for DosS in Mtb.
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Affiliation(s)
- Uma S. Gautam
- Tulane National Primate Research Center, Covington, LA 70433 USA
- Present Address: Duke Human Vaccine Institute, Duke University School of Medicine, 909 S. LaSalle St., Durham, NC 27710 USA
| | - Smriti Mehra
- Tulane National Primate Research Center, Covington, LA 70433 USA
- Department of Pathobiological Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, LA 70803 USA
- Center for Experimental Infectious Diseases Research, Louisiana State University School of Veterinary Medicine, Baton Rouge, LA 70803 USA
| | - Priyanka Kumari
- All India Institute of Medical Sciences, New Delhi, 110029 India
| | - Xavier Alvarez
- Tulane National Primate Research Center, Covington, LA 70433 USA
| | - Tianhua Niu
- Department of Biochemistry, Tulane University School of Medicine, New Orleans, 70112 LA USA
| | - Jaya S. Tyagi
- All India Institute of Medical Sciences, New Delhi, 110029 India
- Centre for Bio-design and Diagnostics, Translational Health Science and Technology Institute Faridabad, Haryana, 121001 India
| | - Deepak Kaushal
- Tulane National Primate Research Center, Covington, LA 70433 USA
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, 70112 LA USA
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23
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Foreman TW, Mehra S, Lackner AA, Kaushal D. Translational Research in the Nonhuman Primate Model of Tuberculosis. ILAR J 2018; 58:151-159. [PMID: 28575319 DOI: 10.1093/ilar/ilx015] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 04/10/2017] [Indexed: 11/14/2022] Open
Abstract
Infection with Mycobacterium tuberculosis predominantly establishes subclinical latent infection over the lifetime of an individual, with a fraction of infected individuals rapidly progressing to active disease. The immune control in latent infection can be perturbed by comorbidities such as diabetes mellitus, obesity, smoking, and coinfection with helminthes or HIV. Modeling the varying aspects of natural infection remains incomplete when using zebrafish and mice. However, the nonhuman primate model of tuberculosis offers a unique and accurate model to investigate host responses to infection, test novel therapeutics, and thoroughly assess preclinical vaccine candidates. Rhesus macaques and cynomolgus macaques manifest the full gamut of clinical and pathological findings in human Mycobacterium tuberculosis infection, including the ability to co-infect macaques with Simian Immunodeficiency Virus to model HIV co-infection. Here we discuss advanced techniques to assay various clinical outcomes of the natural progression of infection as well as therapeutics in development and novel preclinical vaccines. Finally, we survey the translational aspects of nonhuman primate research and argue the urgent need to thoroughly examine preclinical therapeutics and vaccines using this model prior to clinical implementation.
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Affiliation(s)
- Taylor W Foreman
- Tulane National Primate Research Center, Covington, Louisiana.,Tulane University School of Medicine, New Orleans, Louisiana
| | - Smriti Mehra
- Louisiana State University School, Veterinary Medicine, Baton Rouge, Louisiana.,Tulane National Primate Research Center in Covington, Louisiana
| | - Andrew A Lackner
- Tulane National Primate Research Center, Covington, Louisiana.,Immunology and Pathology at Tulane University School of Medicine in New Orleans, Louisiana
| | - Deepak Kaushal
- Tulane National Primate Research Center, Covington, Louisiana.,Immunology at Tulane University School of Medicine, New Orleans, Louisiana.,Department of Medicine, Tulane University School of Medicine in New Orleans, Louisiana
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24
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Vashist A, Malhotra V, Sharma G, Tyagi JS, Clark-Curtiss JE. Interplay of PhoP and DevR response regulators defines expression of the dormancy regulon in virulent Mycobacterium tuberculosis. J Biol Chem 2018; 293:16413-16425. [PMID: 30181216 PMCID: PMC6200940 DOI: 10.1074/jbc.ra118.004331] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 08/15/2018] [Indexed: 11/06/2022] Open
Abstract
The DevR response regulator of Mycobacterium tuberculosis is an established regulator of the dormancy response in mycobacteria and can also be activated during aerobic growth conditions in avirulent strains, suggesting a complex regulatory system. Previously, we reported culture medium-specific aerobic induction of the DevR regulon genes in avirulent M. tuberculosis H37Ra that was absent in the virulent H37Rv strain. To understand the underlying basis of this differential response, we have investigated aerobic expression of the Rv3134c-devR-devS operon using M. tuberculosis H37Ra and H37Rv devR overexpression strains, designated as LIX48 and LIX50, respectively. Overexpression of DevR led to the up-regulation of a large number of DevR regulon genes in aerobic cultures of LIX48, but not in LIX50. To ascertain the involvement of PhoP response regulator, also known to co-regulate a subset of DevR regulon genes, we complemented the naturally occurring mutant phoPRa gene of LIX48 with the WT phoPRv gene. PhoPRv dampened the induced expression of the DevR regulon by >70-80%, implicating PhoP in the negative regulation of devR expression. Electrophoretic mobility shift assays confirmed phosphorylation-independent binding of PhoPRv to the Rv3134c promoter and further revealed that DevR and PhoPRv proteins exhibit differential DNA binding properties to the target DNA. Through co-incubations with DNA, ELISA, and protein complementation assays, we demonstrate that DevR forms a heterodimer with PhoPRv but not with the mutant PhoPRa protein. The study puts forward a new possible mechanism for coordinated expression of the dormancy regulon, having implications in growth adaptations critical for development of latency.
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Affiliation(s)
- Atul Vashist
- the Department of Biotechnology, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Vandana Malhotra
- the Center for Infectious Diseases and Vaccinology, Biodesign Institute, and
- From the Department of Biochemistry, Sri Venkateswara College, University of Delhi, New Delhi 110021, India
| | - Gunjan Sharma
- the Department of Biotechnology, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Jaya Sivaswami Tyagi
- the Department of Biotechnology, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Josephine E Clark-Curtiss
- the Center for Infectious Diseases and Vaccinology, Biodesign Institute, and
- the School of Life Sciences, Arizona State University, Tempe, Arizona 85287, and
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25
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Pacl HT, Reddy VP, Saini V, Chinta KC, Steyn AJC. Host-pathogen redox dynamics modulate Mycobacterium tuberculosis pathogenesis. Pathog Dis 2018; 76:4972762. [PMID: 29873719 PMCID: PMC5989597 DOI: 10.1093/femspd/fty036] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 04/13/2018] [Indexed: 12/18/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, encounters variable and hostile environments within the host. A major component of these hostile conditions is reductive and oxidative stresses induced by factors modified by the host immune response, such as oxygen tension, NO or CO gases, reactive oxygen and nitrogen intermediates, the availability of different carbon sources and changes in pH. It is therefore essential for Mtb to continuously monitor and appropriately respond to the microenvironment. To this end, Mtb has developed various redox-sensitive systems capable of monitoring its intracellular redox environment and coordinating a response essential for virulence. Various aspects of Mtb physiology are regulated by these systems, including drug susceptibility, secretion systems, energy metabolism and dormancy. While great progress has been made in understanding the mechanisms and pathways that govern the response of Mtb to the host's redox environment, many questions in this area remain unanswered. The answers to these questions are promising avenues for addressing the tuberculosis crisis.
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Affiliation(s)
- Hayden T Pacl
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35205, USA
| | - Vineel P Reddy
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35205, USA
| | - Vikram Saini
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35205, USA
| | - Krishna C Chinta
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35205, USA
| | - Adrie J C Steyn
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35205, USA
- Centers for AIDS Research and Free Radical Biology, University of Alabama at Birmingham, Birmingham, Alabama 35205, USA
- Africa Health Research Institute, K-RITH Tower Building, Durban 4001, South Africa
- School of Laboratory Medicine and Medical Sciences, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban 4001, South Africa
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26
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In vivo inhibition of tryptophan catabolism reorganizes the tuberculoma and augments immune-mediated control of Mycobacterium tuberculosis. Proc Natl Acad Sci U S A 2017; 115:E62-E71. [PMID: 29255022 PMCID: PMC5776797 DOI: 10.1073/pnas.1711373114] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mycobacterium tuberculosis continues to cause devastating levels of mortality due to tuberculosis (TB). The failure to control TB stems from an incomplete understanding of the highly specialized strategies that M. tuberculosis utilizes to modulate host immunity and thereby persist in host lungs. Here, we show that M. tuberculosis induced the expression of indoleamine 2,3-dioxygenase (IDO), an enzyme involved in tryptophan catabolism, in macrophages and in the lungs of animals (mice and macaque) with active disease. In a macaque model of inhalation TB, suppression of IDO activity reduced bacterial burden, pathology, and clinical signs of TB disease, leading to increased host survival. This increased protection was accompanied by increased lung T cell proliferation, induction of inducible bronchus-associated lymphoid tissue and correlates of bacterial killing, reduced checkpoint signaling, and the relocation of effector T cells to the center of the granulomata. The enhanced killing of M. tuberculosis in macrophages in vivo by CD4+ T cells was also replicated in vitro, in cocultures of macaque macrophages and CD4+ T cells. Collectively, these results suggest that there exists a potential for using IDO inhibition as an effective and clinically relevant host-directed therapy for TB.
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27
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Veatch AV, Kaushal D. Opening Pandora's Box: Mechanisms of Mycobacterium tuberculosis Resuscitation. Trends Microbiol 2017; 26:145-157. [PMID: 28911979 DOI: 10.1016/j.tim.2017.08.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 07/12/2017] [Accepted: 08/03/2017] [Indexed: 12/27/2022]
Abstract
Mycobacterium tuberculosis (Mtb) characteristically causes an asymptomatic infection. While this latent tuberculosis infection (LTBI) is not contagious, reactivation to active tuberculosis disease (TB) causes the patient to become infectious. A vaccine has existed for TB for a century, while drug treatments have been available for over 70 years; despite this, TB remains a major global health crisis. Understanding the factors which allow the bacillus to control responses to host stress and mechanisms leading to latency are critical for persistence. Similarly, molecular switches which respond to reactivation are important. Recently, research in the field has sought to focus on reactivation, employing system-wide approaches and animal models. Here, we describe the current work that has been done to elucidate the mechanisms of reactivation and stop reactivation in its tracks.
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Affiliation(s)
- Ashley V Veatch
- Divisions of Bacteriology and Parasitology, Tulane National Primate Research Center, Covington, LA, USA; Department of Microbiology & Immunology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Deepak Kaushal
- Divisions of Bacteriology and Parasitology, Tulane National Primate Research Center, Covington, LA, USA; Department of Microbiology & Immunology, Tulane University School of Medicine, New Orleans, LA, USA.
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28
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Phillips BL, Gautam US, Bucsan AN, Foreman TW, Golden NA, Niu T, Kaushal D, Mehra S. LAG-3 potentiates the survival of Mycobacterium tuberculosis in host phagocytes by modulating mitochondrial signaling in an in-vitro granuloma model. PLoS One 2017; 12:e0180413. [PMID: 28880895 PMCID: PMC5589099 DOI: 10.1371/journal.pone.0180413] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 05/28/2017] [Indexed: 11/23/2022] Open
Abstract
CD4+ T-cell mediated Th1 immune responses are critical for immunity to TB. The immunomodulatory protein, lymphocyte activation gene-3 (LAG-3) decreases Th1-type immune responses in T-cells. LAG-3 expression is significantly induced in the lungs of macaques with active TB and correlates with increased bacterial burden. Overproduction of LAG-3 can greatly diminish responses and could lead to uncontrolled Mtb replication. To assess the effect of LAG-3 on the progression of Mtb infection, we developed a co-culture system wherein blood-derived macrophages are infected with Mtb and supplemented with macaque blood or lung derived CD4+ T-cells. Silencing LAG-3 signaling in macaque lung CD4+ T-cells enhanced killing of Mtb in co-cultures, accompanied by reduced mitochondrial electron transport and increased IFN-γ expression. Thus, LAG-3 may modulate adaptive immunity to Mtb infection by interfering with the mitochondrial apoptosis pathway. Better understanding this pathway could allow us to circumvent immune features that promote disease.
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Affiliation(s)
- Bonnie L Phillips
- Tulane National Primate Research Center, Covington, Louisiana, United States of America.,Department of Microbiology & Immunology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Uma S Gautam
- Tulane National Primate Research Center, Covington, Louisiana, United States of America
| | - Allison N Bucsan
- Tulane National Primate Research Center, Covington, Louisiana, United States of America.,Department of Microbiology & Immunology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Taylor W Foreman
- Tulane National Primate Research Center, Covington, Louisiana, United States of America.,Department of Microbiology & Immunology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Nadia A Golden
- Tulane National Primate Research Center, Covington, Louisiana, United States of America
| | - Tianhua Niu
- Department of Biostatistics and Bioinformatics, Tulane University School of Public Health, New Orleans, Louisiana, United States of America
| | - Deepak Kaushal
- Tulane National Primate Research Center, Covington, Louisiana, United States of America.,Department of Microbiology & Immunology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Smriti Mehra
- Tulane National Primate Research Center, Covington, Louisiana, United States of America.,Department of Pathobiological Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, Louisiana, United States of America
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29
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Hudock TA, Foreman TW, Bandyopadhyay N, Gautam US, Veatch AV, LoBato DN, Gentry KM, Golden NA, Cavigli A, Mueller M, Hwang SA, Hunter RL, Alvarez X, Lackner AA, Bader JS, Mehra S, Kaushal D. Hypoxia Sensing and Persistence Genes Are Expressed during the Intragranulomatous Survival of Mycobacterium tuberculosis. Am J Respir Cell Mol Biol 2017; 56:637-647. [PMID: 28135421 DOI: 10.1165/rcmb.2016-0239oc] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Although it is accepted that the environment within the granuloma profoundly affects Mycobacterium tuberculosis (Mtb) and infection outcome, our ability to understand Mtb gene expression in these niches has been limited. We determined intragranulomatous gene expression in human-like lung lesions derived from nonhuman primates with both active tuberculosis (ATB) and latent TB infection (LTBI). We employed a non-laser-based approach to microdissect individual lung lesions and interrogate the global transcriptome of Mtb within granulomas. Mtb genes expressed in classical granulomas with central, caseous necrosis, as well as within the caseum itself, were identified and compared with other Mtb lesions in animals with ATB (n = 7) or LTBI (n = 7). Results were validated using both an oligonucleotide approach and RT-PCR on macaque samples and by using human TB samples. We detected approximately 2,900 and 1,850 statistically significant genes in ATB and LTBI lesions, respectively (linear models for microarray analysis, Bonferroni corrected, P < 0.05). Of these genes, the expression of approximately 1,300 (ATB) and 900 (LTBI) was positively induced. We identified the induction of key regulons and compared our results to genes previously determined to be required for Mtb growth. Our results indicate pathways that Mtb uses to ensure its survival in a highly stressful environment in vivo. A large number of genes is commonly expressed in granulomas with ATB and LTBI. In addition, the enhanced expression of the dormancy survival regulon was a key feature of lesions in animals with LTBI, stressing its importance in the persistence of Mtb during the chronic phase of infection.
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Affiliation(s)
- Teresa A Hudock
- 1 Tulane National Primate Research Center, Covington, Louisiana.,2 Tulane University Health Sciences, New Orleans, Louisiana; and
| | - Taylor W Foreman
- 1 Tulane National Primate Research Center, Covington, Louisiana.,2 Tulane University Health Sciences, New Orleans, Louisiana; and
| | - Nirmalya Bandyopadhyay
- 3 Whitaker Biomedical Engineering Institute, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Uma S Gautam
- 1 Tulane National Primate Research Center, Covington, Louisiana
| | - Ashley V Veatch
- 1 Tulane National Primate Research Center, Covington, Louisiana.,2 Tulane University Health Sciences, New Orleans, Louisiana; and
| | - Denae N LoBato
- 1 Tulane National Primate Research Center, Covington, Louisiana
| | - Kaylee M Gentry
- 1 Tulane National Primate Research Center, Covington, Louisiana
| | - Nadia A Golden
- 1 Tulane National Primate Research Center, Covington, Louisiana
| | - Amy Cavigli
- 1 Tulane National Primate Research Center, Covington, Louisiana
| | | | - Shen-An Hwang
- 4 Department of Pathology and Laboratory Medicine, University of Texas Health Science Center, Houston, Texas
| | - Robert L Hunter
- 4 Department of Pathology and Laboratory Medicine, University of Texas Health Science Center, Houston, Texas
| | - Xavier Alvarez
- 1 Tulane National Primate Research Center, Covington, Louisiana
| | - Andrew A Lackner
- 1 Tulane National Primate Research Center, Covington, Louisiana.,2 Tulane University Health Sciences, New Orleans, Louisiana; and
| | - Joel S Bader
- 3 Whitaker Biomedical Engineering Institute, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Smriti Mehra
- 5 Department of Pathobiological Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, Louisiana
| | - Deepak Kaushal
- 1 Tulane National Primate Research Center, Covington, Louisiana.,2 Tulane University Health Sciences, New Orleans, Louisiana; and
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Duncan C, Jamieson FB, Troudt J, Izzo L, Bielefeldt-Ohmann H, Izzo A, Mehaffy C. Whole transcriptomic and proteomic analyses of an isogenic M. tuberculosis clinical strain with a naturally occurring 15 Kb genomic deletion. PLoS One 2017; 12:e0179996. [PMID: 28650996 PMCID: PMC5484546 DOI: 10.1371/journal.pone.0179996] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 06/07/2017] [Indexed: 11/19/2022] Open
Abstract
Tuberculosis remains one of the most difficult to control infectious diseases in the world. Many different factors contribute to the complexity of this disease. These include the ability of the host to control the infection which may directly relate to nutritional status, presence of co-morbidities and genetic predisposition. Pathogen factors, in particular the ability of different Mycobacterium tuberculosis strains to respond to the harsh environment of the host granuloma, which includes low oxygen and nutrient availability and the presence of damaging radical oxygen and nitrogen species, also play an important role in the success of different strains to cause disease. In this study we evaluated the impact of a naturally occurring 12 gene 15 Kb genomic deletion on the physiology and virulence of M. tuberculosis. The strains denominated ON-A WT (wild type) and ON-A NM (natural mutant) were isolated from a previously reported TB outbreak in an inner city under-housed population in Toronto, Canada. Here we subjected these isogenic strains to transcriptomic (via RNA-seq) and proteomic analyses and identified several gene clusters with differential expression in the natural mutant, including the DosR regulon and the molybdenum cofactor biosynthesis genes, both of which were found in lower abundance in the natural mutant. We also demonstrated lesser virulence of the natural mutant in the guinea pig animal model. Overall, our findings suggest that the ON-A natural mutant is less fit to cause disease, but nevertheless has the potential to cause extended transmission in at-risk populations.
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Affiliation(s)
| | - Frances B. Jamieson
- Public Health Ontario, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - JoLynn Troudt
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| | - Linda Izzo
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| | - Helle Bielefeldt-Ohmann
- School of Veterinary Science, University of Queensland, Gatton, QLD, Australia
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, QLD, Australia
- Australian Infectious Diseases Research Centre, University of Queensland, St Lucia, QLD, Australia
| | - Angelo Izzo
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| | - Carolina Mehaffy
- Public Health Ontario, Toronto, ON, Canada
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
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31
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Novel vaccine potential of Rv3131, a DosR regulon-encoded putative nitroreductase, against hyper-virulent Mycobacterium tuberculosis strain K. Sci Rep 2017; 7:44151. [PMID: 28272457 PMCID: PMC5341159 DOI: 10.1038/srep44151] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 02/03/2017] [Indexed: 12/12/2022] Open
Abstract
Accumulating evidence indicates that latency-associated Mycobacterium tuberculosis (Mtb)-specific antigens from the dormancy survival regulator regulon (DosR) may be promising novel vaccine target antigens for the development of an improved tuberculosis vaccine. After transcriptional profiling of DosR-related genes in the hyper-virulent Beijing Mtb strain K and the reference Mtb strain H37Rv, we selected Rv3131, a hypothetical nitroreductase, as a vaccine antigen and evaluated its vaccine efficacy against Mtb K. Mtb K exhibited stable and constitutive up-regulation of rv3131 relative to Mtb H37Rv under three different growth conditions (at least 2-fold induction) including exponential growth in normal culture conditions, hypoxia, and inside macrophages. Mice immunised with Rv3131 formulated in GLA-SE, a well-defined TLR4 adjuvant, displayed enhanced Rv3131-specific IFN-γ and serum IgG2c responses along with effector/memory T cell expansion and remarkable generation of Rv3131-specific multifunctional CD4+ T cells co-producing TNF-α, IFN-γ and IL-2 in both spleen and lung. Following challenge with Mtb K, the Rv3131/GLA-SE-immunised group exhibited a significant reduction in bacterial number and less extensive lung inflammation accompanied by the obvious persistence of Rv3131-specific multifunctional CD4+ T cells. These results suggest that Rv3131 could be an excellent candidate for potential use in a multi-antigenic Mtb subunit vaccine, especially against Mtb Beijing strains.
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32
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Abstract
Mycobacterium leprae must adopt a metabolic strategy and undergo various metabolic alterations upon infection to survive inside the human body for years in a dormant state. A change in lipid homeostasis upon infection is highly pronounced in Mycobacterium leprae. Lipids play an essential role in the survival and pathogenesis of mycobacteria. Lipids are present in several forms and serve multiple roles from being a source of nutrition, providing rigidity, evading the host immune response to serving as virulence factors, etc. The synthesis and degradation of lipids is a highly regulated process and is the key to future drug designing and diagnosis for mycobacteria. In the current review, an account of the distinct roles served by lipids, the mechanism of their synthesis and degradation has been elucidated.
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Affiliation(s)
- Gurkamaljit Kaur
- Research Scholar, Department of Biotechnology, Panjab University, Chandigarh 160014, India
| | - Jagdeep Kaur
- Department of Biotechnology, Panjab University, Chandigarh 160014, India
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33
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Unique Regulation of the DosR Regulon in the Beijing Lineage of Mycobacterium tuberculosis. J Bacteriol 2016; 199:JB.00696-16. [PMID: 27799329 DOI: 10.1128/jb.00696-16] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 10/25/2016] [Indexed: 12/11/2022] Open
Abstract
The DosR regulon, a set of 48 genes normally expressed in Mycobacterium tuberculosis under conditions that inhibit aerobic respiration, is controlled via the DosR-DosS/DosT two-component system. While the regulon requires induction in most M. tuberculosis isolates, for members of the Beijing lineage, its expression is uncoupled from the need for signaling. In our attempts to understand the mechanistic basis for this uncoupling in the Beijing background, we previously reported the identification of two synonymous single-nucleotide polymorphisms (SNPs) within the adjacent Rv3134c gene. In the present study, we have interrogated the impact of these SNPs on dosR expression in wild-type strains, as well as a range of dosR-dosS-dosT mutants, for both Beijing and non-Beijing M. tuberculosis backgrounds. In this manner, we have unequivocally determined that the C601T dosR promoter SNP is the sole requirement for the dramatic shift in the pattern of DosR regulon expression seen in this globally important lineage. Interestingly, we also show that DosT is completely nonfunctional within these strains. Thus, a complex series of evolutionary steps has led to the present-day Beijing DosR phenotype that, in turn, potentially confers a fitness advantage in the face of some form of host-associated selective pressure. IMPORTANCE Mycobacterium tuberculosis strains of the Beijing lineage have been described as being of enhanced virulence compared to other lineages, and in certain regions, they are associated with the dramatic spread of multidrug-resistant tuberculosis (TB). In terms of trying to understand the functional basis for these broad epidemiological phenomena, it is interesting that, in contrast to the other major lineages, the Beijing strains all constitutively overexpress members of the DosR regulon. Here, we identify the mutational events that led to the evolution of this unique phenotype. In addition, our work highlights the fact that important phenotypic differences exist between distinct M. tuberculosis lineages, with the potential to impact the efficacy of diagnosis, vaccination, and treatment programs.
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34
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Zheng H, Colvin CJ, Johnson BK, Kirchhoff PD, Wilson M, Jorgensen-Muga K, Larsen SD, Abramovitch RB. Inhibitors of Mycobacterium tuberculosis DosRST signaling and persistence. Nat Chem Biol 2016; 13:218-225. [PMID: 27992879 DOI: 10.1038/nchembio.2259] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 09/30/2016] [Indexed: 11/09/2022]
Abstract
The Mycobacterium tuberculosis (Mtb) DosRST two-component regulatory system promotes the survival of Mtb during non-replicating persistence (NRP). NRP bacteria help drive the long course of tuberculosis therapy; therefore, chemical inhibition of DosRST may inhibit the ability of Mtb to establish persistence and thus shorten treatment. Using a DosRST-dependent fluorescent Mtb reporter strain, a whole-cell phenotypic high-throughput screen of a ∼540,000 compound small-molecule library was conducted. The screen discovered novel inhibitors of the DosRST regulon, including three compounds that were subject to follow-up studies: artemisinin, HC102A and HC103A. Under hypoxia, all three compounds inhibit Mtb-persistence-associated physiological processes, including triacylglycerol synthesis, survival and antibiotic tolerance. Artemisinin functions by disabling the heme-based DosS and DosT sensor kinases by oxidizing ferrous heme and generating heme-artemisinin adducts. In contrast, HC103A inhibits DosS and DosT autophosphorylation activity without targeting the sensor kinase heme.
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Affiliation(s)
- Huiqing Zheng
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Christopher J Colvin
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Benjamin K Johnson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Paul D Kirchhoff
- Vahlteich Medicinal Chemistry Core, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA
| | - Michael Wilson
- Vahlteich Medicinal Chemistry Core, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Scott D Larsen
- Vahlteich Medicinal Chemistry Core, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA
| | - Robert B Abramovitch
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
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35
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McLean KJ, Munro AW. Drug targeting of heme proteins in Mycobacterium tuberculosis. Drug Discov Today 2016; 22:566-575. [PMID: 27856345 DOI: 10.1016/j.drudis.2016.11.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 10/28/2016] [Accepted: 11/02/2016] [Indexed: 01/08/2023]
Abstract
TB, caused by the human pathogen Mycobacterium tuberculosis (Mtb), causes more deaths than any other infectious disease. Iron is crucial for Mtb to infect the host and to sustain infection, with Mtb encoding large numbers of iron-binding proteins. Many of these are hemoproteins with key roles, including defense against oxidative stress, cellular signaling and regulation, host cholesterol metabolism, and respiratory processes. Various heme enzymes in Mtb are validated drug targets and/or products of genes essential for bacterial viability or survival in the host. Here, we review the structure, function, and druggability of key Mtb heme enzymes and strategies used for their inhibition.
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Affiliation(s)
- Kirsty J McLean
- School of Chemistry, The University of Manchester, Manchester Institute of Biotechnology, 131 Princess Street, Manchester M1 7DN, UK
| | - Andrew W Munro
- School of Chemistry, The University of Manchester, Manchester Institute of Biotechnology, 131 Princess Street, Manchester M1 7DN, UK.
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36
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Kaur K, Kumari P, Sharma S, Sehgal S, Tyagi JS. DevS/DosS sensor is bifunctional and its phosphatase activity precludes aerobic DevR/DosR regulon expression inMycobacterium tuberculosis. FEBS J 2016; 283:2949-62. [DOI: 10.1111/febs.13787] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 06/04/2016] [Accepted: 06/20/2016] [Indexed: 11/26/2022]
Affiliation(s)
- Kohinoor Kaur
- Department of Biotechnology; All India Institute of Medical Sciences; New Delhi India
| | - Priyanka Kumari
- Department of Biotechnology; All India Institute of Medical Sciences; New Delhi India
| | - Saurabh Sharma
- Department of Biotechnology; All India Institute of Medical Sciences; New Delhi India
| | - Snigdha Sehgal
- Department of Biotechnology; All India Institute of Medical Sciences; New Delhi India
| | - Jaya Sivaswami Tyagi
- Department of Biotechnology; All India Institute of Medical Sciences; New Delhi India
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Basudhar D, Madrona Y, Yukl ET, Sivaramakrishnan S, Nishida CR, Moënne-Loccoz P, Ortiz de Montellano PR. Distal Hydrogen-bonding Interactions in Ligand Sensing and Signaling by Mycobacterium tuberculosis DosS. J Biol Chem 2016; 291:16100-11. [PMID: 27235395 DOI: 10.1074/jbc.m116.724815] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Indexed: 11/06/2022] Open
Abstract
Mycobacterium tuberculosis DosS is critical for the induction of M. tuberculosis dormancy genes in response to nitric oxide (NO), carbon monoxide (CO), or hypoxia. These environmental stimuli, which are sensed by the DosS heme group, result in autophosphorylation of a DosS His residue, followed by phosphotransfer to an Asp residue of the response regulator DosR. To clarify the mechanism of gaseous ligand recognition and signaling, we investigated the hydrogen-bonding interactions of the iron-bound CO and NO ligands by site-directed mutagenesis of Glu-87 and His-89. Autophosphorylation assays and molecular dynamics simulations suggest that Glu-87 has an important role in ligand recognition, whereas His-89 is essential for signal transduction to the kinase domain, a process for which Arg-204 is important. Mutation of Glu-87 to Ala or Gly rendered the protein constitutively active as a kinase, but with lower autophosphorylation activity than the wild-type in the Fe(II) and the Fe(II)-CO states, whereas the E87D mutant had little kinase activity except for the Fe(II)-NO complex. The H89R mutant exhibited attenuated autophosphorylation activity, although the H89A and R204A mutants were inactive as kinases, emphasizing the importance of these residues in communication to the kinase core. Resonance Raman spectroscopy of the wild-type and H89A mutant indicates the mutation does not alter the heme coordination number, spin state, or porphyrin deformation state, but it suggests that interdomain interactions are disrupted by the mutation. Overall, these results confirm the importance of the distal hydrogen-bonding network in ligand recognition and communication to the kinase domain and reveal the sensitivity of the system to subtle differences in the binding of gaseous ligands.
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Affiliation(s)
- Debashree Basudhar
- From the Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, California 94158-2517 and
| | - Yarrow Madrona
- From the Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, California 94158-2517 and
| | - Erik T Yukl
- the Division of Environmental and Biomolecular Systems, Institute of Environmental Health, Oregon Health Science University, Portland, Oregon 97239-3098
| | - Santhosh Sivaramakrishnan
- From the Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, California 94158-2517 and
| | - Clinton R Nishida
- From the Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, California 94158-2517 and
| | - Pierre Moënne-Loccoz
- the Division of Environmental and Biomolecular Systems, Institute of Environmental Health, Oregon Health Science University, Portland, Oregon 97239-3098
| | - Paul R Ortiz de Montellano
- From the Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, California 94158-2517 and
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38
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Mycobacterium tuberculosis Transcription Machinery: Ready To Respond to Host Attacks. J Bacteriol 2016; 198:1360-73. [PMID: 26883824 DOI: 10.1128/jb.00935-15] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Regulating responses to stress is critical for all bacteria, whether they are environmental, commensal, or pathogenic species. For pathogenic bacteria, successful colonization and survival in the host are dependent on adaptation to diverse conditions imposed by the host tissue architecture and the immune response. Once the bacterium senses a hostile environment, it must enact a change in physiology that contributes to the organism's survival strategy. Inappropriate responses have consequences; hence, the execution of the appropriate response is essential for survival of the bacterium in its niche. Stress responses are most often regulated at the level of gene expression and, more specifically, transcription. This minireview focuses on mechanisms of regulating transcription initiation that are required by Mycobacterium tuberculosis to respond to the arsenal of defenses imposed by the host during infection. In particular, we highlight how certain features of M. tuberculosis physiology allow this pathogen to respond swiftly and effectively to host defenses. By enacting highly integrated and coordinated gene expression changes in response to stress,M. tuberculosis is prepared for battle against the host defense and able to persist within the human population.
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Gautam US, Mehra S, Kaushal D. In-Vivo Gene Signatures of Mycobacterium tuberculosis in C3HeB/FeJ Mice. PLoS One 2015; 10:e0135208. [PMID: 26270051 PMCID: PMC4535907 DOI: 10.1371/journal.pone.0135208] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 07/19/2015] [Indexed: 11/28/2022] Open
Abstract
Despite considerable progress in understanding the pathogenesis of Mycobacterium tuberculosis (Mtb), development of new therapeutics and vaccines against it has proven difficult. This is at least in part due to the use of less than optimal models of in-vivo Mtb infection, which has precluded a study of the physiology of the pathogen in niches where it actually persists. C3HeB/FeJ (Kramnik) mice develop human-like lesions when experimentally infected with Mtb and thus make available, a faithful and highly tractable system to study the physiology of the pathogen in-vivo. We compared the transcriptomics of Mtb and various mutants in the DosR (DevR) regulon derived from Kramnik mouse granulomas to those cultured in-vitro. We recently showed that mutant ΔdosS is attenuated in C3HeB/FeJ mice. Aerosol exposure of mice with the mutant mycobacteria resulted in a substantially different and a relatively weaker transcriptional response (< = 20 genes were induced) for the functional category ‘Information Pathways’ in Mtb:ΔdosR; ‘Lipid Metabolism’ in Mtb:ΔdosT; ‘Virulence, Detoxification, Adaptation’ in both Mtb:ΔdosR and Mtb:ΔdosT; and ‘PE/PPE’ family in all mutant strains compare to wild-type Mtb H37Rv, suggesting that the inability to induce DosR functions to different levels can modulate the interaction of the pathogen with the host. The Mtb genes expressed during growth in C3HeB/FeJ mice appear to reflect adaptation to differential nutrient utilization for survival in mouse lungs. The genes such as glnB, Rv0744c, Rv3281, sdhD/B, mce4A, dctA etc. downregulated in mutant ΔdosS indicate their requirement for bacterial growth and flow of carbon/energy source from host cells. We conclude that genes expressed in Mtb during in-vivo chronic phase of infection in Kramnik mice mainly contribute to growth, cell wall processes, lipid metabolism, and virulence.
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Affiliation(s)
- Uma Shankar Gautam
- Tulane National Primate Research Center, Covington, Louisiana, United States of America
- * E-mail: (DK); (USG)
| | - Smriti Mehra
- Tulane National Primate Research Center, Covington, Louisiana, United States of America
- Louisiana State University School of Veterinary Medicine Department of Pathobiological Sciences, Baton Rouge, Louisiana, United States of America
| | - Deepak Kaushal
- Tulane National Primate Research Center, Covington, Louisiana, United States of America
- Microbiology and Immunology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
- * E-mail: (DK); (USG)
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40
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Mehra S, Foreman TW, Didier PJ, Ahsan MH, Hudock TA, Kissee R, Golden NA, Gautam US, Johnson AM, Alvarez X, Russell-Lodrigue KE, Doyle LA, Roy CJ, Niu T, Blanchard JL, Khader SA, Lackner AA, Sherman DR, Kaushal D. The DosR Regulon Modulates Adaptive Immunity and Is Essential for Mycobacterium tuberculosis Persistence. Am J Respir Crit Care Med 2015; 191:1185-96. [PMID: 25730547 DOI: 10.1164/rccm.201408-1502oc] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
RATIONALE Hypoxia promotes dormancy by causing physiologic changes to actively replicating Mycobacterium tuberculosis. DosR controls the response of M. tuberculosis to hypoxia. OBJECTIVES To understand DosR's contribution in the persistence of M. tuberculosis, we compared the phenotype of various DosR regulon mutants and a complemented strain to M. tuberculosis in macaques, which faithfully model M. tuberculosis infection. METHODS We measured clinical and microbiologic correlates of infection with M. tuberculosis relative to mutant/complemented strains in the DosR regulon, studied lung pathology and hypoxia, and compared immune responses in lung using transcriptomics and flow cytometry. MEASUREMENTS AND MAIN RESULTS Despite being able to replicate initially, mutants in DosR regulon failed to persist or cause disease. On the contrary, M. tuberculosis and a complemented strain were able to establish infection and tuberculosis. The attenuation of pathogenesis in animals infected with the mutants coincided with the appearance of a Th1 response and organization of hypoxic lesions wherein M. tuberculosis expressed dosR. The lungs of animals infected with the mutants (but not the complemented strain) exhibited early transcriptional signatures of T-cell recruitment, activation, and proliferation associated with an increase of T cells expressing homing and proliferation markers. CONCLUSIONS Delayed adaptive responses, a hallmark of M. tuberculosis infection, not only lead to persistence but also interfere with the development of effective antituberculosis vaccines. The DosR regulon therefore modulates both the magnitude and the timing of adaptive immune responses in response to hypoxia in vivo, resulting in persistent infection. Hence, DosR regulates key aspects of the M. tuberculosis life cycle and limits lung pathology.
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