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Apiche EA, Yee E, Damodaran AR, Bhagi-Damodaran A. Oxygen affinities of DosT and DosS sensor kinases with implications for hypoxia adaptation in Mycobacterium tuberculosis. J Inorg Biochem 2024; 257:112576. [PMID: 38761578 DOI: 10.1016/j.jinorgbio.2024.112576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/09/2024] [Accepted: 04/23/2024] [Indexed: 05/20/2024]
Abstract
DosT and DosS are heme-based kinases involved in sensing and signaling O2 tension in the microenvironment of Mycobacterium tuberculosis (Mtb). Under conditions of low O2, they activate >50 dormancy-related genes and play a pivotal role in the induction of dormancy and associated drug resistance during tuberculosis infection. In this work, we reexamine the O2 binding affinities of DosT and DosS to show that their equilibrium dissociation constants are 3.3±1.0 μM and 0.46±0.08 μM respectively, which are six to eight-fold stronger than what has been widely referred to in literature. Furthermore, stopped-flow kinetic studies reveal association and dissociation rate constants of 0.84 μM-1 s-1 and 2.8 s-1, respectively for DosT, and 7.2 μM-1 s-1 and 3.3 s-1, respectively for DosS. Remarkably, these tighter O2 binding constants correlate with distinct stages of hypoxia-induced non-replicating persistence in the Wayne model of Mtb. This knowledge opens doors to deconvoluting the intricate interplay between hypoxia adaptation stages and the signal transduction capabilities of these important heme-based O2 sensors.
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Affiliation(s)
- Elizabeth A Apiche
- Department of Chemistry, University of Minnesota, Minneapolis, MN 5545, United States of America
| | - Eaindra Yee
- Department of Chemistry, University of Minnesota, Minneapolis, MN 5545, United States of America
| | - Anoop Rama Damodaran
- Department of Chemistry, University of Minnesota, Minneapolis, MN 5545, United States of America.
| | - Ambika Bhagi-Damodaran
- Department of Chemistry, University of Minnesota, Minneapolis, MN 5545, United States of America.
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2
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Simcox BS, Rohde KH. Orphan response regulator NnaR is critical for nitrate and nitrite assimilation in Mycobacterium abscessus. Front Cell Infect Microbiol 2024; 14:1411333. [PMID: 38854658 PMCID: PMC11162112 DOI: 10.3389/fcimb.2024.1411333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 05/10/2024] [Indexed: 06/11/2024] Open
Abstract
Mycobacterium abscessus (Mab) is an opportunistic pathogen afflicting individuals with underlying lung disease such as Cystic Fibrosis (CF) or immunodeficiencies. Current treatment strategies for Mab infections are limited by its inherent antibiotic resistance and limited drug access to Mab in its in vivo niches resulting in poor cure rates of 30-50%. Mab's ability to survive within macrophages, granulomas and the mucus laden airways of the CF lung requires adaptation via transcriptional remodeling to counteract stresses like hypoxia, increased levels of nitrate, nitrite, and reactive nitrogen intermediates. Mycobacterium tuberculosis (Mtb) is known to coordinate hypoxic adaptation via induction of respiratory nitrate assimilation through the nitrate reductase narGHJI. Mab, on the other hand, does not encode a respiratory nitrate reductase. In addition, our recent study of the transcriptional responses of Mab to hypoxia revealed marked down-regulation of a locus containing putative nitrate assimilation genes, including the orphan response regulator nnaR (nitrate/nitrite assimilation regulator). These putative nitrate assimilation genes, narK3 (nitrate/nitrite transporter), nirBD (nitrite reductase), nnaR, and sirB (ferrochelatase) are arranged contiguously while nasN (assimilatory nitrate reductase identified in this work) is encoded in a different locus. Absence of a respiratory nitrate reductase in Mab and down-regulation of nitrogen metabolism genes in hypoxia suggest interplay between hypoxia adaptation and nitrate assimilation are distinct from what was previously documented in Mtb. The mechanisms used by Mab to fine-tune the transcriptional regulation of nitrogen metabolism in the context of stresses e.g. hypoxia, particularly the role of NnaR, remain poorly understood. To evaluate the role of NnaR in nitrate metabolism we constructed a Mab nnaR knockout strain (MabΔnnaR ) and complement (MabΔnnaR+C ) to investigate transcriptional regulation and phenotypes. qRT-PCR revealed NnaR is necessary for regulating nitrate and nitrite reductases along with a putative nitrate transporter. Loss of NnaR compromised the ability of Mab to assimilate nitrate or nitrite as sole nitrogen sources highlighting its necessity. This work provides the first insights into the role of Mab NnaR setting a foundation for future work investigating NnaR's contribution to pathogenesis.
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Affiliation(s)
| | - Kyle H. Rohde
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
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3
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Apiche EA, Yee E, Damodaran AR, Bhagi-Damodaran A. Oxygen affinities of DosT and DosS sensor kinases with implications for hypoxia adaptation in Mycobacterium tuberculosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.26.582189. [PMID: 38464195 PMCID: PMC10925234 DOI: 10.1101/2024.02.26.582189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
DosT and DosS are heme-based kinases involved in sensing and signaling O2 tension in the microenvironment of Mycobacterium tuberculosis (Mtb). Under conditions of low O2, they activate >50 dormancy-related genes and play a pivotal role in the induction of dormancy and associated drug resistance during tuberculosis infection. In this work, we reexamine the O2 binding affinities of DosT and DosS to show that their equilibrium dissociation constants are 3.3±1 μM and 0.46±0.08 μM respectively, which are six to eight-fold stronger than what has been widely referred to in literature. Furthermore, stopped-flow kinetic studies reveal association and dissociation rate constants of 0.84 μM-1s-1 and 2.8 s-1, respectively for DosT, and 7.2 μM-1s-1 and 3.3 s-1, respectively for DosS. Remarkably, these tighter O2 binding constants correlate with distinct stages of hypoxia-induced non-replicating persistence in the Wayne model of Mtb. This knowledge opens doors to deconvoluting the intricate interplay between hypoxia adaptation stages and the signal transduction capabilities of these important heme-based O2 sensors.
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4
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Matern WM, Harris HT, Danchik C, McDonald M, Patel G, Srivastava A, Ioerger TR, Bader JS, Karakousis PC. Functional Whole Genome Screen of Nutrient-Starved Mycobacterium tuberculosis Identifies Genes Involved in Rifampin Tolerance. Microorganisms 2023; 11:2269. [PMID: 37764112 PMCID: PMC10534295 DOI: 10.3390/microorganisms11092269] [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: 08/08/2023] [Revised: 09/05/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), poses a global health challenge and is responsible for over a million deaths each year. Current treatment is lengthy and complex, and new, abbreviated regimens are urgently needed. Mtb adapts to nutrient starvation, a condition experienced during host infection, by shifting its metabolism and becoming tolerant to the killing activity of bactericidal antibiotics. An improved understanding of the mechanisms mediating antibiotic tolerance in Mtb can serve as the basis for developing more effective therapies. We performed a forward genetic screen to identify candidate Mtb genes involved in tolerance to the two key first-line antibiotics, rifampin and isoniazid, under nutrient-rich and nutrient-starved conditions. In nutrient-rich conditions, we found 220 mutants with differential antibiotic susceptibility (218 in the rifampin screen and 2 in the isoniazid screen). Following Mtb adaptation to nutrient starvation, 82 mutants showed differential antibiotic susceptibility (80 in the rifampin screen and 2 in the isoniazid screen). Using targeted mutagenesis, we validated the rifampin-hypersusceptible phenotype under nutrient starvation in Mtb mutants lacking the following genes: ercc3, moeA1, rv0049, and rv2179c. These findings shed light on potential therapeutic targets, which could help shorten the duration and complexity of antitubercular regimens.
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Affiliation(s)
- William M. Matern
- Department of Biomedical Engineering, Institute for Computational Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (W.M.M.)
- Center for Systems Approaches to Infectious Diseases (C-SAID), School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (H.T.H.)
- Tuberculosis Research Advancement Center, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Harley T. Harris
- Center for Systems Approaches to Infectious Diseases (C-SAID), School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (H.T.H.)
- Tuberculosis Research Advancement Center, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Carina Danchik
- Center for Systems Approaches to Infectious Diseases (C-SAID), School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (H.T.H.)
- Tuberculosis Research Advancement Center, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Marissa McDonald
- Center for Systems Approaches to Infectious Diseases (C-SAID), School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (H.T.H.)
- Tuberculosis Research Advancement Center, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Gopi Patel
- Center for Systems Approaches to Infectious Diseases (C-SAID), School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (H.T.H.)
- Tuberculosis Research Advancement Center, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Aashish Srivastava
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA;
| | - Thomas R. Ioerger
- Department of Computer Science and Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Joel S. Bader
- Department of Biomedical Engineering, Institute for Computational Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (W.M.M.)
- Center for Systems Approaches to Infectious Diseases (C-SAID), School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (H.T.H.)
| | - Petros C. Karakousis
- Center for Systems Approaches to Infectious Diseases (C-SAID), School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (H.T.H.)
- Tuberculosis Research Advancement Center, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
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5
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Matern WM, Harris HT, Danchik C, McDonald M, Patel G, Srivastava A, Ioerger TR, Bader JS, Karakousis PC. Functional whole genome screen of nutrient-starved Mycobacterium tuberculosis identifies genes involved in antibiotic tolerance. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.12.536593. [PMID: 37090629 PMCID: PMC10120713 DOI: 10.1101/2023.04.12.536593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Mycobacterium tuberculosis ( Mtb ), the causative agent of tuberculosis (TB), poses a global health challenge and is responsible for over a million deaths each year. Current treatment is lengthy and complex, and new, abbreviated regimens are urgently needed. Mtb adapts to nutrient starvation, a condition experienced during host infection, by shifting its metabolism and becoming tolerant to the killing activity of bactericidal antibiotics. An improved understanding of the mechanisms mediating antibiotic tolerance in Mtb can serve as the basis for developing more effective therapies. We performed a forward genetic screen to identify candidate Mtb genes involved in tolerance to the two key first-line antibiotics, rifampin and isoniazid, under nutrient-rich and nutrient-starved conditions. In nutrient-rich conditions, we found 220 mutants with differential antibiotic susceptibility (218 in the rifampin screen and 2 in the isoniazid screen). Following Mtb adaptation to nutrient starvation, 82 mutants showed differential antibiotic susceptibility (80 in the rifampin screen and 2 in the isoniazid screen). Using targeted mutagenesis, we validated the rifampin-hypersusceptible phenotype under nutrient starvation in Mtb mutants lacking the following genes: ercc3 , moeA1 , rv0049 , and rv2179c . These findings shed light on potential therapeutic targets, which could help shorten the duration and complexity of antitubercular regimens. Importance Treatment of Mtb infection requires a long course of combination antibiotics, likely due to subpopulations of tolerant bacteria exhibiting decreased susceptibility to antibiotics. Identifying and characterizing the genetic pathways involved in antibiotic tolerance is expected to yield therapeutic targets for the development of novel TB treatment-shortening regimens.
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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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Sarmah DT, Parveen R, Kundu J, Chatterjee S. Latent tuberculosis and computational biology: A less-talked affair. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 178:17-31. [PMID: 36781150 DOI: 10.1016/j.pbiomolbio.2023.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 02/09/2023] [Accepted: 02/10/2023] [Indexed: 02/13/2023]
Abstract
Tuberculosis (TB) is a pervasive and devastating air-borne disease caused by the organisms belonging to the Mycobacterium tuberculosis (Mtb) complex. Currently, it is the global leader in infectious disease-related death in adults. The proclivity of TB to enter the latent state has become a significant impediment to the global effort to eradicate TB. Despite decades of research, latent tuberculosis (LTB) mechanisms remain poorly understood, making it difficult to develop efficient treatment methods. In this review, we seek to shed light on the current understanding of the mechanism of LTB, with an accentuation on the insights gained through computational biology. We have outlined various well-established computational biology components, such as omics, network-based techniques, mathematical modelling, artificial intelligence, and molecular docking, to disclose the crucial facets of LTB. Additionally, we highlighted important tools and software that may be used to conduct a variety of systems biology assessments. Finally, we conclude the article by addressing the possible future directions in this field, which might help a better understanding of LTB progression.
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Affiliation(s)
- Dipanka Tanu Sarmah
- Complex Analysis Group, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, 121001, India
| | - Rubi Parveen
- Complex Analysis Group, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, 121001, India
| | - Jayendrajyoti Kundu
- Complex Analysis Group, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, 121001, India
| | - Samrat Chatterjee
- Complex Analysis Group, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, 121001, India.
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Bo H, Moure UAE, Yang Y, Pan J, Li L, Wang M, Ke X, Cui H. Mycobacterium tuberculosis-macrophage interaction: Molecular updates. Front Cell Infect Microbiol 2023; 13:1062963. [PMID: 36936766 PMCID: PMC10020944 DOI: 10.3389/fcimb.2023.1062963] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 02/13/2023] [Indexed: 03/06/2023] Open
Abstract
Mycobacterium tuberculosis (Mtb), the causative agent of Tuberculosis (TB), remains a pathogen of great interest on a global scale. This airborne pathogen affects the lungs, where it interacts with macrophages. Acidic pH, oxidative and nitrosative stressors, and food restrictions make the macrophage's internal milieu unfriendly to foreign bodies. Mtb subverts the host immune system and causes infection due to its genetic arsenal and secreted effector proteins. In vivo and in vitro research have examined Mtb-host macrophage interaction. This interaction is a crucial stage in Mtb infection because lung macrophages are the first immune cells Mtb encounters in the host. This review summarizes Mtb effectors that interact with macrophages. It also examines how macrophages control and eliminate Mtb and how Mtb manipulates macrophage defense mechanisms for its own survival. Understanding these mechanisms is crucial for TB prevention, diagnosis, and treatment.
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Affiliation(s)
- Haotian Bo
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Ulrich Aymard Ekomi Moure
- The Ninth People's Hospital of Chongqing, Affiliated Hospital of Southwest University, Chongqing, China
- Cancer Center, Medical Research Institute, Southwest University, Chongqing, China
| | - Yuanmiao Yang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Jun Pan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Li Li
- Cancer Center, Medical Research Institute, Southwest University, Chongqing, China
| | - Miao Wang
- Cancer Center, Medical Research Institute, Southwest University, Chongqing, China
| | - Xiaoxue Ke
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Cancer Center, Medical Research Institute, Southwest University, Chongqing, China
- *Correspondence: Hongjuan Cui, ; Xiaoxue Ke,
| | - Hongjuan Cui
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Cancer Center, Medical Research Institute, Southwest University, Chongqing, China
- Jinfeng Laboratory, Chongqing, China
- *Correspondence: Hongjuan Cui, ; Xiaoxue Ke,
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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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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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11
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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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12
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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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13
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Joshi H, Kandari D, Bhatnagar R. Insights into the molecular determinants involved in Mycobacterium tuberculosis persistence and their therapeutic implications. Virulence 2021; 12:2721-2749. [PMID: 34637683 PMCID: PMC8565819 DOI: 10.1080/21505594.2021.1990660] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/17/2021] [Accepted: 10/05/2021] [Indexed: 01/08/2023] Open
Abstract
The establishment of persistent infections and the reactivation of persistent bacteria to active bacilli are the two hurdles in effective tuberculosis treatment. Mycobacterium tuberculosis, an etiologic tuberculosis agent, adapts to numerous antibiotics and resists the host immune system causing a disease of public health concern. Extensive research has been employed to combat this disease due to its sheer ability to persist in the host system, undetected, waiting for the opportunity to declare itself. Persisters are a bacterial subpopulation that possesses transient tolerance to high doses of antibiotics. There are certain inherent mechanisms that facilitate the persister cell formation in Mycobacterium tuberculosis, some of those had been characterized in the past namely, stringent response, transcriptional regulators, energy production pathways, lipid metabolism, cell wall remodeling enzymes, phosphate metabolism, and proteasome protein degradation. This article reviews the recent advancements made in various in vitro persistence models that assist to unravel the mechanisms involved in the persister cell formation and to hunt for the possible preventive or treatment measures. To tackle the persister population the immunodominant proteins that express specifically at the latent phase of infection can be used for diagnosis to distinguish between the active and latent tuberculosis, as well as to select potential drug or vaccine candidates. In addition, we discuss the genes engaged in the persistence to get more insights into resuscitation and persister cell formation. The in-depth understanding of persistent cells of mycobacteria can certainly unravel novel ways to target the pathogen and tackle its persistence.
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Affiliation(s)
- Hemant Joshi
- Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Divya Kandari
- Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Rakesh Bhatnagar
- Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
- Amity University of Rajasthan, Jaipur, Rajasthan, India
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14
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Lopes LGF, Carvalho EM, Sousa EHS. A bioinorganic chemistry perspective on the roles of metals as drugs and targets against Mycobacterium tuberculosis - a journey of opportunities. Dalton Trans 2021; 49:15988-16003. [PMID: 32583835 DOI: 10.1039/d0dt01365j] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Medicinal inorganic chemists have provided many strategies to tackle a myriad of diseases, pushing forward the frontiers of pharmacology. As an example, the fight against tuberculosis (TB), an infectious bacterial disease, has led to the development of metal-based compounds as potential drugs. This disease remains a current health issue causing over 1.4 million of deaths per year. The emergence of multi- (MDR) and extensively-drug resistant (XDR) Mycobacterium tuberculosis (Mtb) strains along with a long dormancy process, place major challenges in developing new therapeutic compounds. Isoniazid is a front-line prodrug used against TB with appealing features for coordination chemists, which have been explored in a series of cases reported here. An isoniazid iron-based compound, called IQG-607, has caught our attention, whose in vitro and in vivo studies are advanced and thoroughly discussed, along with other metal complexes. Isoniazid is inactive against dormant Mtb, a hard to eliminate state of this bacillus, found in one-fourth of the world's population and directly implicated in the lengthy treatment of TB (ca. 6 months). Thus, our understanding of this phenomenon may lead to a rational design of new drugs. Along these lines, we describe how metals as targets can cross paths with metals used as selective therapeutics, where we mainly review heme-based sensors, DevS and DosT, as a key system in the Mtb dormancy process and a current drug target. Overall, we report new opportunities for bioinorganic chemists to tackle this longstanding and current threat.
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Affiliation(s)
- Luiz G F Lopes
- Group of Bioinorganic, Department of Organic and Inorganic Chemistry, Federal University of Ceará, Fortaleza, Brazil.
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15
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Xu F, Zhang H, Si X, Chen J, Chen Y, Cui X, Qin Y. Assessment of CD27 expression on T-cells as a diagnostic and therapeutic tool for patients with smear-negative pulmonary tuberculosis. BMC Immunol 2021; 22:41. [PMID: 34176483 PMCID: PMC8237462 DOI: 10.1186/s12865-021-00430-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 06/14/2021] [Indexed: 12/03/2022] Open
Abstract
Background There is a global focus on illness diagnosis in smear-negative and latent tuberculosis infectious populations (SN-TB and LTBI). CD27 has been suggested to play a direct role in active TB. Little is known about smear-negative individuals. Here, we tried to investigate whether it has a role in smear-negative populations. The expression of CD27 and MTB-specific CD27 in CD4+ T cells (“CD27−CD4+” and “CD27−IFN-γ+CD4+”) was evaluated in MTB-unexposed controls (HC), TB contacts (TB-C) and SN-TB individuals by flow cytometry. The sensitivity, specificity and AUC (area under curve) of “CD27−IFN-γ+CD4+” cells to distinguish SN-TBs from HCs and TB-Cs were determined by receiver operating characteristic (ROC) curve analysis. The clinical index was selected from the clinical laboratory and evaluated for correlation with “CD27−IFN-γ+CD4+” cells by Spearman statistical analysis. Results We observed that the percentages of “CD27−IFN-γ+CD4+” cells were significantly increased in the SN-TB group compared with the HC and TB-C groups (AUC was 0.88, sensitivity was 82.14%, specificity was 80.00%, and P < 0.0001). The percentage of “CD27−IFN-γ+CD4+” cells was negatively correlated with WBC (white blood cell count) (r = − 0.3019, P = 0.0182) and positively correlated with IgE (immunoglobulin E) (r = 0.2805, P = 0.0362). Furthermore, “CD27−IFN-γ+CD4+” cells were significantly decreased, especially in the > 50 years group, after clinical treatment. Conclusion The present results demonstrated that the percentage of “CD27−IFN-γ+CD4+” cells might be a conceivable molecular indicator in the diagnosis of SN-TB and was influenced by its outcome of therapy. Supplementary Information The online version contains supplementary material available at 10.1186/s12865-021-00430-y.
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Affiliation(s)
- Feifan Xu
- Department of Pathogen Biology, School of Medicine, Nantong University, Nantong, 226001, China.,Department of Clinical Laboratory, The Sixth People's Hospital of Nantong, Nantong, 226011, China
| | - Haiyun Zhang
- Department of Clinical Laboratory, The Sixth People's Hospital of Nantong, Nantong, 226011, China
| | - Xiaoyan Si
- Department of Clinical Laboratory, The Sixth People's Hospital of Nantong, Nantong, 226011, China
| | - Junlin Chen
- Department of Tuberculosis, The Sixth People's Hospital of Nantong, Nantong, 226011, China
| | - Yuhao Chen
- Department of General Surgery, Affiliated Hospital of Nantong University, Nantong, China
| | - Xiaopeng Cui
- Department of General Surgery, Affiliated Hospital of Nantong University, Nantong, China.
| | - Yongwei Qin
- Department of Pathogen Biology, School of Medicine, Nantong University, Nantong, 226001, China.
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16
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Heme Oxygenase-1 as a Pharmacological Target for Host-Directed Therapy to Limit Tuberculosis Associated Immunopathology. Antioxidants (Basel) 2021; 10:antiox10020177. [PMID: 33530574 PMCID: PMC7911872 DOI: 10.3390/antiox10020177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/22/2021] [Accepted: 01/22/2021] [Indexed: 12/11/2022] Open
Abstract
Excessive inflammation and tissue damage are pathological hallmarks of chronic pulmonary tuberculosis (TB). Despite decades of research, host regulation of these clinical consequences is poorly understood. A sustained effort has been made to understand the contribution of heme oxygenase-1 (HO-1) to this process. HO-1 is an essential cytoprotective enzyme in the host that controls inflammation and oxidative stress in many pathological conditions. While HO-1 levels are upregulated in animals and patients infected with Mycobacterium tuberculosis (Mtb), how it regulates host responses and disease pathology during TB remains unclear. This lack of clarity is due in part to contradictory studies arguing that HO-1 induction contributes to both host resistance as well as disease progression. In this review, we discuss these conflicting studies and the role of HO-1 in modulating myeloid cell functions during Mtb disease progression. We argue that HO-1 is a promising target for host-directed therapy to improve TB immunopathology.
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17
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Identification and in silico functional prediction of lineage-specific SNPs distributed in DosR-related proteins and resuscitation-promoting factor proteins of Mycobacterium tuberculosis. Heliyon 2020; 6:e05744. [PMID: 33364506 PMCID: PMC7753917 DOI: 10.1016/j.heliyon.2020.e05744] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/21/2020] [Accepted: 12/11/2020] [Indexed: 11/23/2022] Open
Abstract
One-third of the world population is infected by Mycobacterium tuberculosis, which may persist in the latent or dormant state. Bacteria can shift to dormancy when encountering harsh conditions such as low oxygen, nutrient starvation, high acidity and host immune defenses. Genes related to the dormancy survival regulator (DosR) regulon are responsible for the inhibition of aerobic respiration and replication, which is required to enter dormancy. Conversely, resuscitation-promoting factor (rpf) proteins participate in reactivation from dormancy and the development of active tuberculosis (TB). Many DosR regulon and rpf proteins are immunodominant T cell antigens that are highly expressed in latent TB infection. They could serve as TB vaccine candidates and be used for diagnostic development. We explored the genetic polymorphisms of 50 DosR-related genes and 5 rpf genes among 1,170 previously sequenced clinical M. tuberculosis genomes. Forty-three lineage- or sublineage-specific nonsynonymous single nucleotide polymorphisms (nsSNPs) were identified. Ten nsSNPs were specific to all Mtb isolates belonging to lineage 1 (L1). Two common sublineages, the Beijing family (L2.2) and EAI2 (L1.2.1), differed at as many as 26 lineage- or sublineage-specific SNPs. DosR regulon genes related to membrane proteins and the rpf family possessed mean dN/dS ratios greater than one, suggesting that they are under positive selection. Although the T cell epitope regions of DosR-related and rpf antigens were quite conserved, we found that the epitopes in L1 had higher rates of genetic polymorphisms than the other lineages. Some mutations in immunogenic epitopes of the antigens were specific to particular M. tuberculosis lineages. Therefore, the genetic diversity of the DosR regulon and rpf proteins might impact the adaptation of M. tuberculosis to the dormant state and the immunogenicity of latency antigens, which warrants further investigation.
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18
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Sousa EH, Carepo MS, Moura JJ. Nitrate-nitrite fate and oxygen sensing in dormant Mycobacterium tuberculosis: A bioinorganic approach highlighting the importance of transition metals. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2020.213476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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19
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Potential therapeutic approaches for a sleeping pathogen: tuberculosis a case for bioinorganic chemistry. J Biol Inorg Chem 2020; 25:685-704. [PMID: 32676771 DOI: 10.1007/s00775-020-01803-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 06/30/2020] [Indexed: 12/18/2022]
Abstract
Mycobacterium tuberculosis (Mtb) has an old history as a human pathogen and still kills over one million people every year. One key feature of this bacterium is its dormancy: a phenomenon responsible for major changes in its metabolism and replication that have been associated with the need for a lengthy therapy for Mtb. This process is regulated by key heme-based sensors, particularly DosT and DevS (DosS), among other co-regulators, and also linked to nitrogen utilization (nitrate/nitrite) and stringent responses. In face of the current threat of tuberculosis, there is an urgent need to develop new therapeutic agents capable of targeting the dormant state, associated with the need for a lengthy therapy. Interestingly, many of those key proteins are indeed metallo-containing or metallo-dependent biomolecules, opening exciting bioinorganic opportunities. Here, we critically reviewed a series of small molecules targeting key proteins involved in these processes, including DosT/DevS/DevR, RegX3, MprA, MtrA, NarL, PknB, Rel, PPK, nitrate and nitrite reductases, GlnA1, aiming for new opportunities and alternative therapies. In the battle against Mycobacterium tuberculosis, new drug targets must be searched, in particular those involved in dormancy. A series of exciting cases for drug development involving metallo-containing or metallo-dependent biomolecules are reviewed, opening great opportunities for the bioinorganic chemistry community.
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