1
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Kim NK, Baek JE, Lee YJ, Oh Y, Oh JI. Rel-dependent decrease in the expression of ribosomal protein genes by inhibition of the respiratory electron transport chain in Mycobacterium smegmatis. Front Microbiol 2024; 15:1448277. [PMID: 39188315 PMCID: PMC11345224 DOI: 10.3389/fmicb.2024.1448277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2024] [Accepted: 07/24/2024] [Indexed: 08/28/2024] Open
Abstract
In this study, we demonstrated that both the expression of most ribosomal protein genes and the amount of ribosomes were decreased in the Δaa 3 mutant of Mycobacterium smegmatis, in which the major terminal oxidase (aa 3 cytochrome c oxidase) of the respiratory electron transport chain (ETC) is inactivated, compared to those in the wild-type strain. Deletion of the rel gene encoding the major (p)ppGpp synthetase in the background of the Δaa 3 mutant restored the reduced expression of ribosomal protein genes, suggesting that inhibition of the respiratory ETC leads to the Rel-dependent stringent response (SR) in this bacterium. Both a decrease in the expression of ribosomal protein genes by overexpression of rel and the increased expression of rel in the Δaa 3 mutant relative to the wild-type strain support the Rel-dependent induction of SR in the Δaa 3 mutant. We also demonstrated that the expression of ribosomal protein genes was decreased in M. smegmatis exposed to respiration-inhibitory conditions, such as KCN and bedaquiline treatment, null mutation of the cytochrome bcc 1 complex, and hypoxia. The MprBA-SigE-SigB regulatory pathway was implicated in both the increased expression of rel and the decreased expression of ribosomal protein genes in the Δaa 3 mutant of M. smegmatis.
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Affiliation(s)
- Na-Kyeong Kim
- Department of Integrated Biological Science, Pusan National University, Busan, Republic of Korea
| | - Jong-Eun Baek
- Department of Integrated Biological Science, Pusan National University, Busan, Republic of Korea
| | - Ye-Jin Lee
- Department of Integrated Biological Science, Pusan National University, Busan, Republic of Korea
| | - Yuna Oh
- Department of Integrated Biological Science, Pusan National University, Busan, Republic of Korea
| | - Jeong-Il Oh
- Department of Integrated Biological Science, Pusan National University, Busan, Republic of Korea
- Microbiological Resource Research Institute, Pusan National University, Busan, Republic of Korea
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2
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Liu X, Hu J, Wang W, Yang H, Tao E, Ma Y, Sha S. Mycobacterial Biofilm: Mechanisms, Clinical Problems, and Treatments. Int J Mol Sci 2024; 25:7771. [PMID: 39063012 PMCID: PMC11277187 DOI: 10.3390/ijms25147771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2024] [Revised: 07/12/2024] [Accepted: 07/13/2024] [Indexed: 07/28/2024] Open
Abstract
Tuberculosis (TB) remains a threat to human health worldwide. Mycobacterium tuberculosis (Mtb) and other nontuberculous mycobacteria (NTM) can form biofilms, and in vitro and animal experiments have shown that biofilms cause serious drug resistance and mycobacterial persistence. Deeper investigations into the mechanisms of mycobacterial biofilm formation and, consequently, the exploration of appropriate antibiofilm treatments to improve the efficiency of current anti-TB drugs will be useful for curing TB. In this review, the genes and molecules that have been recently reported to be involved in mycobacterial biofilm development, such as ABC transporter, Pks1, PpiB, GroEL1, MprB, (p)ppGpp, poly(P), and c-di-GMP, are summarized. Biofilm-induced clinical problems, including biofilm-related infections and enhanced virulence, as well as their possible mechanisms, are also discussed in detail. Moreover, we also illustrate newly synthesized anti-TB agents that target mycobacterial biofilm, as well as some assistant methods with high efficiency in reducing biofilms in hosts, such as the use of nanoparticles.
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Affiliation(s)
- Xining Liu
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044, China; (X.L.); (J.H.); (W.W.); (E.T.)
| | - Junxing Hu
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044, China; (X.L.); (J.H.); (W.W.); (E.T.)
| | - Wenzhen Wang
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044, China; (X.L.); (J.H.); (W.W.); (E.T.)
| | - Hanyu Yang
- The Queen’s University of Belfast Joint College, China Medical University, Shenyang 110122, China;
| | - Erning Tao
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044, China; (X.L.); (J.H.); (W.W.); (E.T.)
| | - Yufang Ma
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044, China; (X.L.); (J.H.); (W.W.); (E.T.)
| | - Shanshan Sha
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044, China; (X.L.); (J.H.); (W.W.); (E.T.)
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3
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Bacon EE, Myers KS, Iruegas-López R, Banta AB, Place M, Ebersberger I, Peters JM. Physiological Roles of an Acinetobacter-specific σ Factor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.08.602572. [PMID: 39026751 PMCID: PMC11257525 DOI: 10.1101/2024.07.08.602572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
The Gram-negative pathogen Acinetobacter baumannii is considered an "urgent threat" to human health due to its propensity to become antibiotic resistant. Understanding the distinct regulatory paradigms used by A. baumannii to mitigate cellular stresses may uncover new therapeutic targets. Many γ-proteobacteria use the extracytoplasmic function (ECF) σ factor, RpoE, to invoke envelope homeostasis networks in response to stress. Acinetobacter species contain the poorly characterized ECF "SigAb;" however, it is unclear if SigAb has the same physiological role as RpoE. Here, we show that SigAb is a metal stress-responsive ECF that appears unique to Acinetobacter species and distinct from RpoE. We combine promoter mutagenesis, motif scanning, and ChIP-seq to define the direct SigAb regulon, which consists of sigAb itself, the stringent response mediator, relA, and the uncharacterized small RNA, "sabS." However, RNA-seq of strains overexpressing SigAb revealed a large, indirect regulon containing hundreds of genes. Metal resistance genes are key elements of the indirect regulon, as CRISPRi knockdown of sigAb or sabS resulted in increased copper sensitivity and excess copper induced SigAb-dependent transcription. Further, we found that two uncharacterized genes in the sigAb operon, "aabA" and "aabB", have anti-SigAb activity. Finally, employing a targeted Tn-seq approach that uses CRISPR-associated transposons, we show that sigAb, aabA, and aabB are important for fitness even during optimal growth conditions. Our work reveals new physiological roles for SigAb and SabS, provides a novel approach for assessing gene fitness, and highlights the distinct regulatory architecture of A. baumannii.
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Affiliation(s)
- Emily E. Bacon
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Kevin S. Myers
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - Rubén Iruegas-López
- Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Germany
| | - Amy B. Banta
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Michael Place
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Ingo Ebersberger
- Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Germany
- Senckenberg Biodiversity and Climate Research Centre (S-BIKF), Frankfurt, Germany
- LOEWE Center for Translational Biodiversity Genomics (TBG), Frankfurt, Germany
| | - Jason M. Peters
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI, USA
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4
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Liu Y, Li H, Dai D, He J, Liang Z. Gene Regulatory Mechanism of Mycobacterium Tuberculosis during Dormancy. Curr Issues Mol Biol 2024; 46:5825-5844. [PMID: 38921019 PMCID: PMC11203133 DOI: 10.3390/cimb46060348] [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: 04/10/2024] [Revised: 06/05/2024] [Accepted: 06/07/2024] [Indexed: 06/27/2024] Open
Abstract
Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb) complex, is a zoonotic disease that remains one of the leading causes of death worldwide. Latent tuberculosis infection reactivation is a challenging obstacle to eradicating TB globally. Understanding the gene regulatory network of Mtb during dormancy is important. This review discusses up-to-date information about TB gene regulatory networks during dormancy, focusing on the regulation of lipid and energy metabolism, dormancy survival regulator (DosR), White B-like (Wbl) family, Toxin-Antitoxin (TA) systems, sigma factors, and MprAB. We outline the progress in vaccine and drug development associated with Mtb dormancy.
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Affiliation(s)
- Yiduo Liu
- College of Animal Science and Technology, Guangxi University, No. 100 University West Road, Nanning 530004, China (D.D.)
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Han Li
- College of Animal Science and Technology, Guangxi University, No. 100 University West Road, Nanning 530004, China (D.D.)
| | - Dejia Dai
- College of Animal Science and Technology, Guangxi University, No. 100 University West Road, Nanning 530004, China (D.D.)
| | - Jiakang He
- College of Animal Science and Technology, Guangxi University, No. 100 University West Road, Nanning 530004, China (D.D.)
| | - Zhengmin Liang
- College of Animal Science and Technology, Guangxi University, No. 100 University West Road, Nanning 530004, China (D.D.)
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Shivangi, Khan Y, Ekka MK, Meena LS. Structural and functional characterization of mycobacterial PhoH2 and identification of potential inhibitor of its enzymatic activity. Braz J Microbiol 2024; 55:1033-1051. [PMID: 38386260 PMCID: PMC11153397 DOI: 10.1007/s42770-024-01267-4] [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: 11/09/2023] [Accepted: 01/30/2024] [Indexed: 02/23/2024] Open
Abstract
Mycobacterium tuberculosis is composed of a cumbersome signaling and protein network which partakes in bacterial survival and augments its pathogenesis. Mycobacterial PhoH2 (Mt-PhoH2) is a signaling element and a predictive phosphate starvation protein that works in an ATP-dependent manner. Here, we elaborated the characterization of Mt-PhoH2 through biophysical, biochemical, and computational methods. In addition to its intrinsic ATPase activity, the biochemical experiments revealed its GTPase activity and both activities are metal ion dependent. Magnesium, manganese, copper, iron, nickel, zinc, cesium, calcium, and lithium were examined for their effect on activity, and the optimum activity was found with 10 mM of Mg2+ ions. The kinetic parameters of 3 µM Mt-PhoH2 were observed as Km 4.873 ± 0.44 µM, Vmax 12.3817 ± 0.084 µM/min/mg, Kcat 0.0075 ± 0.00005 s-1, and Kcat/Km 0.0015 ± 0.000001 µM-1 s-1 with GTP. In the case of GTP as a substrate, a 20% decrease in enzymatic activity and a 50% increase in binding affinity of Mt-PhoH2 were observed. The substrates ADP and GDP inhibit the ATPase and GTPase activity of Mt-PhoH2. CD spectroscopy showed the dominance of alpha helix in the secondary structure of Mt-PhoH2, and this structural pattern was altered upon addition of ATP and GTP. In silico inhibitor screening revealed ML141 and NAV_2729 as two potential inhibitors of the catalytic activity of Mt-PhoH2. Mt-PhoH2 is essential for mycobacterial growth as its knockdown strain showed a decreased growth effect. Overall, the present article emphasizes the factors essential for the proper functioning of Mt-PhoH2 which is a participant in the toxin-antitoxin machinery and may also play an important role in phosphate starvation.
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Affiliation(s)
- Shivangi
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-HRDC, Ghaziabad, Uttar Pradesh, 201 002, India
| | - Yasmeen Khan
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-HRDC, Ghaziabad, Uttar Pradesh, 201 002, India
| | - Mary Krishna Ekka
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-HRDC, Ghaziabad, Uttar Pradesh, 201 002, India
| | - Laxman S Meena
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India.
- Academy of Scientific and Innovative Research (AcSIR), CSIR-HRDC, Ghaziabad, Uttar Pradesh, 201 002, India.
- CSIR-Central Drug Research Institute, Lucknow, 226031, India.
- CSIR-Institute of Genomics and Integrative Biology, Academy of Scientific & Innovative Research (AcSIR), Mall Road, Delhi, 110007, India.
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6
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Cioetto-Mazzabò L, Sorze D, Babic F, Boldrin F, Segafreddo G, Provvedi R, Manganelli R. Structure of the SigE regulatory network in Mycobacterium tuberculosis. Front Microbiol 2024; 15:1407500. [PMID: 38873166 PMCID: PMC11173970 DOI: 10.3389/fmicb.2024.1407500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Accepted: 05/15/2024] [Indexed: 06/15/2024] Open
Abstract
SigE is one of the main regulators of mycobacterial stress response and is characterized by a complex regulatory network based on two pathways, which have been partially characterized in conditions of surface stress. The first pathway is based on the induction of sigE transcription by the two-component system MprAB, while the second is based on the degradation of SigE anti-sigma factor RseA by ClpC1P2, a protease whose structural genes are induced by ClgR. We characterized the dynamics of the SigE network activation in conditions of surface stress and low pH in Mycobacterium tuberculosis. Using a series of mutants in which the main regulatory nodes of the network have been inactivated, we could explore their hierarchy, and we determined that MprAB had a key role in the network activation in both stress conditions through the induction of sigE. However, while in conditions of surface stress the absence of MprAB totally abrogated sigE induction, under low pH conditions it only resulted in a small delay of the induction of sigE. In this case, sigE induction was due to SigH, which acted as a MprAB backup system. The ClgR pathway, leading to the degradation of the SigE anti-sigma factor RseA, was shown to be essential for the activation of the SigE network only following surface stress, where it showed an equal hierarchy with the MprAB pathway.
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Affiliation(s)
| | - Davide Sorze
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Fedora Babic
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Francesca Boldrin
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Greta Segafreddo
- Department of Molecular Medicine, University of Padova, Padova, Italy
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7
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Rijal R, Gomer RH. Gallein potentiates isoniazid's ability to suppress Mycobacterium tuberculosis growth. Front Microbiol 2024; 15:1369763. [PMID: 38690363 PMCID: PMC11060752 DOI: 10.3389/fmicb.2024.1369763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 04/01/2024] [Indexed: 05/02/2024] Open
Abstract
Mycobacterium tuberculosis (Mtb), the bacterium that causes tuberculosis (TB), can be difficult to treat because of drug tolerance. Increased intracellular polyphosphate (polyP) in Mtb enhances tolerance to antibiotics, and capsular polyP in Neisseria gonorrhoeae potentiates resistance to antimicrobials. The mechanism by which bacteria utilize polyP to adapt to antimicrobial pressure is not known. In this study, we found that Mtb adapts to the TB frontline antibiotic isoniazid (INH) by enhancing the accumulation of cellular, extracellular, and cell surface polyP. Gallein, a broad-spectrum inhibitor of the polyphosphate kinase that synthesizes polyP, prevents this INH-induced increase in extracellular and cell surface polyP levels. Gallein and INH work synergistically to attenuate Mtb's ability to grow in in vitro culture and within human macrophages. Mtb when exposed to INH, and in the presence of INH, gallein inhibits cell envelope formation in most but not all Mtb cells. Metabolomics indicated that INH or gallein have a modest impact on levels of Mtb metabolites, but when used in combination, they significantly reduce levels of metabolites involved in cell envelope synthesis and amino acid, carbohydrate, and nucleoside metabolism, revealing a synergistic effect. These data suggest that gallein represents a promising avenue to potentiate the treatment of TB.
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Affiliation(s)
- Ramesh Rijal
- Gomer Lab, Department of Biology, Texas A&M University, College Station, TX, United States
| | - Richard H. Gomer
- Gomer Lab, Department of Biology, Texas A&M University, College Station, TX, United States
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Skoog EJ, Bosak T. Predicted metabolic roles and stress responses provide insights into candidate phyla Hydrogenedentota and Sumerlaeota as members of the rare biosphere in biofilms from various environments. ENVIRONMENTAL MICROBIOLOGY REPORTS 2024; 16:e13228. [PMID: 38192240 PMCID: PMC10866078 DOI: 10.1111/1758-2229.13228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 12/11/2023] [Indexed: 01/10/2024]
Abstract
Pustular mats from Shark Bay, Western Australia, host complex microbial communities bound within an organic matrix. These mats harbour many poorly characterized organisms with low relative abundances (<1%), such as candidate phyla Hydrogenedentota and Sumerlaeota. Here, we aim to constrain the metabolism and physiology of these candidate phyla by analyzing two representative metagenome-assembled genomes (MAGs) from a pustular mat. Metabolic reconstructions of these MAGs suggest facultatively anaerobic, chemoorganotrophic lifestyles of both organisms and predict that both MAGs can metabolize a diversity of carbohydrate substrates. Ca. Sumerlaeota possesses genes involved in degrading chitin, cellulose and other polysaccharides, while Ca. Hydrogenedentota can metabolize cellulose derivatives in addition to glycerol, fatty acids and phosphonates. Both Ca. phyla can respond to nitrosative stress and participate in nitrogen metabolism. Metabolic comparisons of MAGs from Shark Bay and those from various polyextreme environments (i.e., hot springs, hydrothermal vents, subsurface waters, anaerobic digesters, etc.) reveal similar metabolic capabilities and adaptations to hypersalinity, oxidative stress, antibiotics, UV radiation, nitrosative stress, heavy metal toxicity and life in surface-attached communities. These adaptations and capabilities may account for the widespread nature of these organisms and their contributions to biofilm communities in a range of extreme surface and subsurface environments.
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Affiliation(s)
- Emilie J. Skoog
- Department of Earth, Atmospheric and Planetary SciencesMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
- Integrative Oceanography DivisionScripps Institution of Oceanography, UC San DiegoLa JollaCaliforniaUSA
| | - Tanja Bosak
- Department of Earth, Atmospheric and Planetary SciencesMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
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9
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Rijal R, Gomer RH. Gallein and isoniazid act synergistically to attenuate Mycobacterium tuberculosis growth in human macrophages. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.10.574965. [PMID: 38260681 PMCID: PMC10802476 DOI: 10.1101/2024.01.10.574965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Mycobacterium tuberculosis (Mtb), the bacterium that causes tuberculosis (TB), can be difficult to treat because of drug resistance. Increased intracellular polyphosphate (polyP) in Mtb enhances resistance to antibiotics, and capsular polyP in Neisseria gonorrhoeae potentiates resistance to antimicrobials. The mechanism by which bacteria utilize polyP to adapt to antimicrobial pressure is not known. In this study, we found that Mtb adapts to the TB frontline antibiotic isoniazid (INH) by enhancing the accumulation of cellular, extracellular, and cell surface polyP. Gallein, a broad-spectrum inhibitor of the polyphosphate kinase that synthesizes polyP, prevents this INH-induced increase in extracellular and cell surface polyP levels. Gallein and INH work synergistically to attenuate Mtb's ability to grow in in vitro culture and within human macrophages. Mtb when exposed to INH, and in the presence of INH, gallein inhibits cell envelope formation in most but not all Mtb cells. Metabolomics indicated that INH or gallein have a modest impact on levels of Mtb metabolites, but when used in combination, they significantly reduce levels of metabolites involved in cell envelope synthesis and amino acid, carbohydrate, and nucleoside metabolism, revealing a synergistic effect. These data suggest that gallein represents a promising avenue to potentiate the treatment of TB.
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Affiliation(s)
- Ramesh Rijal
- Department of Biology, Texas A&M University, College Station, TX 77843-3474, USA
| | - Richard H. Gomer
- Department of Biology, Texas A&M University, College Station, TX 77843-3474, USA
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10
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Chugh S, Tiwari P, Suri C, Gupta SK, Singh P, Bouzeyen R, Kidwai S, Srivastava M, Rameshwaram NR, Kumar Y, Asthana S, Singh R. Polyphosphate kinase-1 regulates bacterial and host metabolic pathways involved in pathogenesis of Mycobacterium tuberculosis. Proc Natl Acad Sci U S A 2024; 121:e2309664121. [PMID: 38170746 PMCID: PMC10786269 DOI: 10.1073/pnas.2309664121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 12/01/2023] [Indexed: 01/05/2024] Open
Abstract
Inorganic polyphosphate (polyP) is primarily synthesized by Polyphosphate Kinase-1 (PPK-1) and regulates numerous cellular processes, including energy metabolism, stress adaptation, drug tolerance, and microbial pathogenesis. Here, we report that polyP interacts with acyl CoA carboxylases, enzymes involved in lipid biosynthesis in Mycobacterium tuberculosis. We show that deletion of ppk-1 in M. tuberculosis results in transcriptional and metabolic reprogramming. In comparison to the parental strain, the Δppk-1 mutant strain had reduced levels of virulence-associated lipids such as PDIMs and TDM. We also observed that polyP deficiency in M. tuberculosis is associated with enhanced phagosome-lysosome fusion in infected macrophages and attenuated growth in mice. Host RNA-seq analysis revealed decreased levels of transcripts encoding for proteins involved in either type I interferon signaling or formation of foamy macrophages in the lungs of Δppk-1 mutant-infected mice relative to parental strain-infected animals. Using target-based screening and molecular docking, we have identified raloxifene hydrochloride as a broad-spectrum PPK-1 inhibitor. We show that raloxifene hydrochloride significantly enhanced the activity of isoniazid, bedaquiline, and pretomanid against M. tuberculosis in macrophages. Additionally, raloxifene inhibited the growth of M. tuberculosis in mice. This is an in-depth study that provides mechanistic insights into the regulation of mycobacterial pathogenesis by polyP deficiency.
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Affiliation(s)
- Saurabh Chugh
- Translational Health Science and Technology Institute, National Capital Region Biotech Science Cluster, Faridabad121001, India
| | - Prabhakar Tiwari
- Translational Health Science and Technology Institute, National Capital Region Biotech Science Cluster, Faridabad121001, India
| | - Charu Suri
- Translational Health Science and Technology Institute, National Capital Region Biotech Science Cluster, Faridabad121001, India
| | - Sonu Kumar Gupta
- Translational Health Science and Technology Institute, National Capital Region Biotech Science Cluster, Faridabad121001, India
| | - Padam Singh
- Translational Health Science and Technology Institute, National Capital Region Biotech Science Cluster, Faridabad121001, India
| | - Rania Bouzeyen
- Institut Pasteur de Tunis, Laboratory of Transmission, Control and Immunobiology of Infections, LRII IPT02, Tunis1002, Tunisia
| | - Saqib Kidwai
- Translational Health Science and Technology Institute, National Capital Region Biotech Science Cluster, Faridabad121001, India
| | - Mitul Srivastava
- Translational Health Science and Technology Institute, National Capital Region Biotech Science Cluster, Faridabad121001, India
| | - Nagender Rao Rameshwaram
- Translational Health Science and Technology Institute, National Capital Region Biotech Science Cluster, Faridabad121001, India
| | - Yashwant Kumar
- Translational Health Science and Technology Institute, National Capital Region Biotech Science Cluster, Faridabad121001, India
| | - Shailendra Asthana
- Translational Health Science and Technology Institute, National Capital Region Biotech Science Cluster, Faridabad121001, India
| | - Ramandeep Singh
- Translational Health Science and Technology Institute, National Capital Region Biotech Science Cluster, Faridabad121001, India
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11
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Borghi F, Saiardi A. Evolutionary perspective on mammalian inorganic polyphosphate (polyP) biology. Biochem Soc Trans 2023; 51:1947-1956. [PMID: 37844192 PMCID: PMC10657179 DOI: 10.1042/bst20230483] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/06/2023] [Accepted: 10/10/2023] [Indexed: 10/18/2023]
Abstract
Inorganic polyphosphate (polyP), the polymeric form of phosphate, is attracting ever-growing attention due to the many functions it appears to perform within mammalian cells. This essay does not aim to systematically review the copious mammalian polyP literature. Instead, we examined polyP synthesis and functions in various microorganisms and used an evolutionary perspective to theorise key issues of this field and propose solutions. By highlighting the presence of VTC4 in distinct species of very divergent eucaryote clades (Opisthokonta, Viridiplantae, Discoba, and the SAR), we propose that whilst polyP synthesising machinery was present in the ancestral eukaryote, most lineages subsequently lost it during evolution. The analysis of the bacteria-acquired amoeba PPK1 and its unique polyP physiology suggests that eukaryote cells must have developed mechanisms to limit cytosolic polyP accumulation. We reviewed the literature on polyP in the mitochondria from the perspective of its endosymbiotic origin from bacteria, highlighting how mitochondria could possess a polyP physiology reminiscent of their 'bacterial' beginning that is not yet investigated. Finally, we emphasised the similarities that the anionic polyP shares with the better-understood negatively charged polymers DNA and RNA, postulating that the nucleus offers an ideal environment where polyP physiology might thrive.
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Affiliation(s)
- Filipy Borghi
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, U.K
| | - Adolfo Saiardi
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, U.K
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12
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Sinha S, RS N, Devarakonda Y, Rathi A, Reddy Regatti P, Batra S, Syal K. Tale of Twin Bifunctional Second Messenger (p)ppGpp Synthetases and Their Function in Mycobacteria. ACS OMEGA 2023; 8:32258-32270. [PMID: 37720788 PMCID: PMC10500699 DOI: 10.1021/acsomega.3c03557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Accepted: 08/16/2023] [Indexed: 09/19/2023]
Abstract
M. tuberculosis, an etiological agent of tuberculosis, requires a long treatment regimen due to its ability to respond to stress and persist inside the host. The second messenger (p)ppGpp-mediated stress response plays a critical role in such long-term survival, persistence, and antibiotic tolerance which may also lead to the emergence of multiple drug resistance. In mycobacteria, (pp)pGpp molecules are synthesized predominantly by two bifunctional enzymes-long RSH-Rel and short SAS-RelZ. The long RSH-Rel is a major (p)ppGpp synthetase and hydrolase. How it switches its activity from synthesis to hydrolysis remains unclear. RelMtb mutant has been reported to be defective in biofilm formation, cell wall function, and persister cell formation. The survival of such mutants has also been observed to be compromised in infection models. In M. smegmatis, short SAS-RelZ has RNase HII activity in addition to (pp)Gpp synthesis activity. The RNase HII function of RelZ has been implicated in resolving replication-transcription conflicts by degrading R-loops. However, the mechanism and regulatory aspects of such a regulation remain elusive. In this article, we have discussed (p)ppGpp metabolism and its role in managing the stress response network of mycobacteria, which is responsible for long-term survival inside the host, making it an important therapeutic target.
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Affiliation(s)
- Shubham
Kumar Sinha
- Genetics and Molecular Microbiology
Laboratory, Department of Biological Sciences, Institute of Eminence, Birla Institute of Technology and Sciences-Pilani, Hyderabad campus, Hyderabad, Telangana, India, 500078
| | - Neethu RS
- Genetics and Molecular Microbiology
Laboratory, Department of Biological Sciences, Institute of Eminence, Birla Institute of Technology and Sciences-Pilani, Hyderabad campus, Hyderabad, Telangana, India, 500078
| | - Yogeshwar Devarakonda
- Genetics and Molecular Microbiology
Laboratory, Department of Biological Sciences, Institute of Eminence, Birla Institute of Technology and Sciences-Pilani, Hyderabad campus, Hyderabad, Telangana, India, 500078
| | - Ajita Rathi
- Genetics and Molecular Microbiology
Laboratory, Department of Biological Sciences, Institute of Eminence, Birla Institute of Technology and Sciences-Pilani, Hyderabad campus, Hyderabad, Telangana, India, 500078
| | - Pavan Reddy Regatti
- Genetics and Molecular Microbiology
Laboratory, Department of Biological Sciences, Institute of Eminence, Birla Institute of Technology and Sciences-Pilani, Hyderabad campus, Hyderabad, Telangana, India, 500078
| | - Sakshi Batra
- Genetics and Molecular Microbiology
Laboratory, Department of Biological Sciences, Institute of Eminence, Birla Institute of Technology and Sciences-Pilani, Hyderabad campus, Hyderabad, Telangana, India, 500078
| | - Kirtimaan Syal
- Genetics and Molecular Microbiology
Laboratory, Department of Biological Sciences, Institute of Eminence, Birla Institute of Technology and Sciences-Pilani, Hyderabad campus, Hyderabad, Telangana, India, 500078
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13
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Manca B, Buffi G, Magri G, Del Vecchio M, Taddei AR, Pezzicoli A, Giuliani M. Functional characterization of the gonococcal polyphosphate pseudo-capsule. PLoS Pathog 2023; 19:e1011400. [PMID: 37216411 DOI: 10.1371/journal.ppat.1011400] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 05/03/2023] [Indexed: 05/24/2023] Open
Abstract
Neisseria gonorrhoeae is an exclusively human pathogen able to evade the host immune system through multiple mechanisms. Gonococci accumulate a large portion of phosphate moieties as polyphosphate (polyP) on the exterior of the cell. Although its polyanionic nature has suggested that it may form a protective shield on the cell surface, its role remains controversial. Taking advantage of a recombinant His-tagged polyP-binding protein, the presence of a polyP pseudo-capsule in gonococcus was demonstrated. Interestingly, the polyP pseudo-capsule was found to be present in specific strains only. To investigate its putative role in host immune evasion mechanisms, such as resistance to serum bactericidal activity, antimicrobial peptides and phagocytosis, the enzymes involved in polyP metabolism were genetically deleted, generating mutants with altered polyP external content. The mutants with lower polyP content on their surface compared to the wild-type strains, became sensitive to complement-mediated killing in presence of normal human serum. Conversely, naturally serum sensitive strains that did not display a significant polyP pseudo-capsule became resistant to complement in the presence of exogenous polyP. The presence of polyP pseudo-capsule was also critical in the protection from antibacterial activity of cationic antimicrobial peptide, such as cathelicidin LL-37. Results showed that the minimum bactericidal concentration was lower in strains lacking polyP than in those harboring the pseudo-capsule. Data referring to phagocytic killing resistance, assessed by using neutrophil-like cells, showed a significant decrease in viability of mutants lacking polyP on their cell surface in comparison to the wild-type strain. The addition of exogenous polyP overturned the killing phenotype of sensitive strains suggesting that gonococcus could exploit environmental polyP to survive to complement-mediated, cathelicidin and intracellular killing. Taken together, data presented here indicate an essential role of the polyP pseudo-capsule in the gonococcal pathogenesis, opening new perspective on gonococcal biology and more effective treatments.
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Affiliation(s)
- Benedetta Manca
- Pharmacy and Biotechnology Department (FaBiT), University of Bologna, Bologna, Italy C/O GSK, Siena, Italy
| | | | | | | | - Anna Rita Taddei
- Centre for High Instruments, Electron Microscopy Section, University of Tuscia, Viterbo, Italy
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14
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Baruzzo G, Serafini A, Finotello F, Sanavia T, Cioetto-Mazzabò L, Boldrin F, Lavezzo E, Barzon L, Toppo S, Provvedi R, Manganelli R, Di Camillo B. Role of the Extracytoplasmic Function Sigma Factor SigE in the Stringent Response of Mycobacterium tuberculosis. Microbiol Spectr 2023; 11:e0294422. [PMID: 36946740 PMCID: PMC10100808 DOI: 10.1128/spectrum.02944-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 02/15/2023] [Indexed: 03/23/2023] Open
Abstract
Bacteria respond to nutrient starvation implementing the stringent response, a stress signaling system resulting in metabolic remodeling leading to decreased growth rate and energy requirements. A well-characterized model of stringent response in Mycobacterium tuberculosis is the one induced by growth in low phosphate. The extracytoplasmic function (ECF) sigma factor SigE was previously suggested as having a key role in the activation of stringent response. In this study, we challenge this hypothesis by analyzing the temporal dynamics of the transcriptional response of a sigE mutant and its wild-type parental strain to low phosphate using RNA sequencing. We found that both strains responded to low phosphate with a typical stringent response trait, including the downregulation of genes encoding ribosomal proteins and RNA polymerase. We also observed transcriptional changes that support the occurring of an energetics imbalance, compensated by a reduced activity of the electron transport chain, decreased export of protons, and a remodeling of central metabolism. The most striking difference between the two strains was the induction in the sigE mutant of several stress-related genes, in particular, the genes encoding the ECF sigma factor SigH and the transcriptional regulator WhiB6. Since both proteins respond to redox unbalances, their induction suggests that the sigE mutant is not able to maintain redox homeostasis in response to the energetics imbalance induced by low phosphate. In conclusion, our data suggest that SigE is not directly involved in initiating stringent response but in protecting the cell from stress consequent to the low phosphate exposure and activation of stringent response. IMPORTANCE Mycobacterium tuberculosis can enter a dormant state enabling it to establish latent infections and to become tolerant to antibacterial drugs. Dormant bacteria's physiology and the mechanism(s) used by bacteria to enter dormancy during infection are still unknown due to the lack of reliable animal models. However, several in vitro models, mimicking conditions encountered during infection, can reproduce different aspects of dormancy (growth arrest, metabolic slowdown, drug tolerance). The stringent response, a stress response program enabling bacteria to cope with nutrient starvation, is one of them. In this study, we provide evidence suggesting that the sigma factor SigE is not directly involved in the activation of stringent response as previously hypothesized, but it is important to help the bacteria to handle the metabolic stress related to the adaptation to low phosphate and activation of stringent response, thus giving an important contribution to our understanding of the mechanism behind stringent response development.
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Affiliation(s)
- Giacomo Baruzzo
- Department of Information Engineering, University of Padova, Padua, Italy
| | - Agnese Serafini
- Department of Molecular Medicine, University of Padova, Padua, Italy
| | | | - Tiziana Sanavia
- Department of Information Engineering, University of Padova, Padua, Italy
| | | | - Francesca Boldrin
- Department of Molecular Medicine, University of Padova, Padua, Italy
| | - Enrico Lavezzo
- Department of Molecular Medicine, University of Padova, Padua, Italy
| | - Luisa Barzon
- Department of Molecular Medicine, University of Padova, Padua, Italy
| | - Stefano Toppo
- Department of Molecular Medicine, University of Padova, Padua, Italy
| | | | | | - Barbara Di Camillo
- Department of Information Engineering, University of Padova, Padua, Italy
- Department of Comparative Biomedicine and Food Science, University of Padova, Padua, Italy
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15
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He C, Li B, Gong Z, Huang S, Liu X, Wang J, Xie J, Shi T. Polyphosphate kinase 1 is involved in formation, the morphology and ultramicrostructure of biofilm of Mycobacterium smegmatis and its survivability in macrophage. Heliyon 2023; 9:e14513. [PMID: 36967885 PMCID: PMC10034464 DOI: 10.1016/j.heliyon.2023.e14513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 03/06/2023] [Accepted: 03/09/2023] [Indexed: 03/17/2023] Open
Abstract
The most unique characteristic of Mycobacterium tuberculosis is persistence in the human host, and the biofilm formation is related to the persistance. Polyphosphate (polyP) kinase 1 (PPK1) is conserved in Mycobacteria and is responsible for polyP synthesis. polyP is a chain molecule linked by high-energy phosphate bonds, which is considered to play a very important role in bacterial persistence. However, the relationship of PPK1 and mycobacterial biofilm formation is still adequately unclear. In current study, ppk1-deficient mutant (MT), ppk1-complemented (CT) and wild-type strains of M. smegmatis mc2 155 were used to investigate the formation, morphology and ultramicrostructure of the biofilm and to analyze the lipid levels and susceptibility to vancomycin antibiotic. And then WT, MT and CT strains were used to infect macrophages and to analyze the expression levels of various inflammatory factors, respectively. We found that PPK1 was required for M. smegmatis polyP production in vivo and polyP deficiency not only attenuated the biofilm formation, but also altered the phenotype and ultramicrostructure of the biofilm and reduced the cell lipid composition (except for C16.1 and C17.1, most of the fatty acid components from C8-C24). Moreover, the ppk1-deficient mutant was also significantly more sensitive to vancomycin which targets the cell wall, and its ability to survive in macrophages was decreased, which was related to the change of the expression level of inflammatory factors in macrophage. This study demonstrates that the PPK1 can affect the biofilm structure through affecting the content of short chain fatty acid and promote intracellular survival of M. smegmatis by altering the expression of inflammatory factors. These findings establish a basis for investigating the role of PPK1 in the persistence of M. tuberculosis, and provide clues for treating latent infection of M. tuberculosis with PPK1 as a potential drug target.
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Affiliation(s)
- Cailin He
- Medical School of Hubei Minzu University, Enshi, 445000, China
| | - Bo Li
- Medical School of Hubei Minzu University, Enshi, 445000, China
| | - Zhen Gong
- Institute of Modern Biopharmaceuticals, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Sheng Huang
- Medical School of Hubei Minzu University, Enshi, 445000, China
- Institute of Selenium Science and Industry of Hubei Minzu University, Enshi, 445000, China
| | - Xu Liu
- Medical School of Hubei Minzu University, Enshi, 445000, China
- Institute of Selenium Science and Industry of Hubei Minzu University, Enshi, 445000, China
| | - Jiajun Wang
- Medical School of Hubei Minzu University, Enshi, 445000, China
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals, School of Life Sciences, Southwest University, Chongqing, 400715, China
- Corresponding author. Institute of Modern Biopharmaceuticals, School of Life Sciences, Southwest University, Chongqing, 400715, China.
| | - Tingyu Shi
- Medical School of Hubei Minzu University, Enshi, 445000, China
- Hubei Key Laboratory of Biological Resources Protection and Utilization, Enshi, 445000, China
- Institute of Selenium Science and Industry of Hubei Minzu University, Enshi, 445000, China
- Corresponding author. Medical School of Hubei Minzu University, Enshi, 445000, China.
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16
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Oh Y, Lee HN, Ko EM, Jeong JA, Park SW, Oh JI. Mycobacterial Regulatory Systems Involved in the Regulation of Gene Expression Under Respiration-Inhibitory Conditions. J Microbiol 2023; 61:297-315. [PMID: 36847970 DOI: 10.1007/s12275-023-00026-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/31/2023] [Accepted: 02/01/2023] [Indexed: 03/01/2023]
Abstract
Mycobacterium tuberculosis is the causative agent of tuberculosis. M. tuberculosis can survive in a dormant state within the granuloma, avoiding the host-mounting immune attack. M. tuberculosis bacilli in this state show increased tolerance to antibiotics and stress conditions, and thus the transition of M. tuberculosis to the nonreplicating dormant state acts as an obstacle to tuberculosis treatment. M. tuberculosis in the granuloma encounters hostile environments such as hypoxia, nitric oxide, reactive oxygen species, low pH, and nutrient deprivation, etc., which are expected to inhibit respiration of M. tuberculosis. To adapt to and survive in respiration-inhibitory conditions, it is required for M. tuberculosis to reprogram its metabolism and physiology. In order to get clues to the mechanism underlying the entry of M. tuberculosis to the dormant state, it is important to understand the mycobacterial regulatory systems that are involved in the regulation of gene expression in response to respiration inhibition. In this review, we briefly summarize the information regarding the regulatory systems implicated in upregulation of gene expression in mycobacteria exposed to respiration-inhibitory conditions. The regulatory systems covered in this review encompass the DosSR (DevSR) two-component system, SigF partner switching system, MprBA-SigE-SigB signaling pathway, cAMP receptor protein, and stringent response.
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Affiliation(s)
- Yuna Oh
- Department of Integrated Biological Science, Pusan National University, Busan, 46241, Republic of Korea
| | - Ha-Na Lee
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Eon-Min Ko
- Division of Bacterial Disease Research, Center for Infectious Disease Research, Korea Disease Control and Prevention Agency, National Institute of Infectious Diseases, National Institute of Health, Osong, 28159, Republic of Korea
| | - Ji-A Jeong
- Division of Bacterial Disease Research, Center for Infectious Disease Research, Korea Disease Control and Prevention Agency, National Institute of Infectious Diseases, National Institute of Health, Osong, 28159, Republic of Korea
| | - Sae Woong Park
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Jeong-Il Oh
- Department of Integrated Biological Science, Pusan National University, Busan, 46241, Republic of Korea. .,Microbiological Resource Research Institute, Pusan National University, Busan, 46241, Republic of Korea.
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17
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Manganelli R, Cioetto-Mazzabò L, Segafreddo G, Boldrin F, Sorze D, Conflitti M, Serafini A, Provvedi R. SigE: A master regulator of Mycobacterium tuberculosis. Front Microbiol 2023; 14:1075143. [PMID: 36960291 PMCID: PMC10027907 DOI: 10.3389/fmicb.2023.1075143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 02/16/2023] [Indexed: 03/09/2023] Open
Abstract
The Extracellular function (ECF) sigma factor SigE is one of the best characterized out of the 13 sigma factors encoded in the Mycobacterium tuberculosis chromosome. SigE is required for blocking phagosome maturation and full virulence in both mice and guinea pigs. Moreover, it is involved in the response to several environmental stresses as surface stress, oxidative stress, acidic pH, and phosphate starvation. Underscoring its importance in M. tuberculosis physiology, SigE is subjected to a very complex regulatory system: depending on the environmental conditions, its expression is regulated by three different sigma factors (SigA, SigE, and SigH) and a two-component system (MprAB). SigE is also regulated at the post-translational level by an anti-sigma factor (RseA) which is regulated by the intracellular redox potential and by proteolysis following phosphorylation from PknB upon surface stress. The set of genes under its direct control includes other regulators, as SigB, ClgR, and MprAB, and genes involved in surface remodeling and stabilization. Recently SigE has been shown to interact with PhoP to activate a subset of genes in conditions of acidic pH. The complex structure of its regulatory network has been suggested to result in a bistable switch leading to the development of heterogeneous bacterial populations. This hypothesis has been recently reinforced by the finding of its involvement in the development of persister cells able to survive to the killing activity of several drugs.
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Affiliation(s)
- Riccardo Manganelli
- Department of Molecular Medicine, University of Padova, Padova, Italy
- *Correspondence: Riccardo Manganelli,
| | | | - Greta Segafreddo
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Francesca Boldrin
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Davide Sorze
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Marta Conflitti
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Agnese Serafini
- Department of Molecular Medicine, University of Padova, Padova, Italy
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18
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Keppler M, Moser S, Jessen HJ, Held C, Andexer JN. Make or break: the thermodynamic equilibrium of polyphosphate kinase-catalysed reactions. Beilstein J Org Chem 2022; 18:1278-1288. [PMID: 36225726 PMCID: PMC9520863 DOI: 10.3762/bjoc.18.134] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 08/30/2022] [Indexed: 11/23/2022] Open
Abstract
Polyphosphate kinases (PPKs) have become popular biocatalysts for nucleotide 5'-triphosphate (NTP) synthesis and regeneration. Two unrelated families are described: PPK1 and PPK2. They are structurally unrelated and use different catalytic mechanisms. PPK1 enzymes prefer the usage of adenosine 5'-triphosphate (ATP) for polyphosphate (polyP) synthesis while PPK2 enzymes favour the reverse reaction. With the emerging use of PPK enzymes in biosynthesis, a deeper understanding of the enzymes and their thermodynamic reaction course is of need, especially in comparison to other kinases. Here, we tested four PPKs from different organisms under the same conditions without any coupling reactions. In comparison to other kinases using phosphate donors with comparably higher phosphate transfer potentials that are characterised by reaction yields close to full conversion, the PPK-catalysed reaction reaches an equilibrium in which about 30% ADP is left. These results were obtained for PPK1 and PPK2 enzymes, and are supported by theoretical data on the basic reaction. At high concentrations of substrate, the different kinetic preferences of PPK1 and PPK2 can be observed. The implications of these results for the application of PPKs in chemical synthesis and as enzymes for ATP regeneration systems are discussed.
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Affiliation(s)
- Michael Keppler
- Institute of Pharmaceutical Sciences, University of Freiburg, Albertstr. 25, 79104 Freiburg, Germany
| | - Sandra Moser
- Institute of Organic Chemistry, University of Freiburg, Albertstr. 21, 79104 Freiburg, Germany
| | - Henning J Jessen
- Institute of Organic Chemistry, University of Freiburg, Albertstr. 21, 79104 Freiburg, Germany
| | - Christoph Held
- Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Str. 70, 44227 Dortmund, Germany
| | - Jennifer N Andexer
- Institute of Pharmaceutical Sciences, University of Freiburg, Albertstr. 25, 79104 Freiburg, Germany
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19
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Activation of the SigE-SigB signaling pathway by inhibition of the respiratory electron transport chain and its effect on rifampicin resistance in Mycobacterium smegmatis. J Microbiol 2022; 60:935-947. [DOI: 10.1007/s12275-022-2202-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/01/2022] [Accepted: 07/05/2022] [Indexed: 10/16/2022]
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20
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Jiang Z, Zhuang Z, Mi K. Experimental Evolution Reveals Redox State Modulates Mycobacterial Pathogenicity. Front Genet 2022; 13:758304. [PMID: 35368697 PMCID: PMC8965865 DOI: 10.3389/fgene.2022.758304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 02/10/2022] [Indexed: 11/19/2022] Open
Abstract
Understanding how Mycobacterium tuberculosis has evolved into a professional pathogen is helpful in studying its pathogenesis and for designing vaccines. We investigated how the evolutionary adaptation of M. smegmatis mc251 to an important clinical stressor H2O2 allows bacteria to undergo coordinated genetic mutations, resulting in increased pathogenicity. Whole-genome sequencing identified a mutation site in the fur gene, which caused increased expression of katG. Using a Wayne dormancy model, mc251 showed a growth advantage over its parental strain mc2155 in recovering from dormancy under anaerobic conditions. Meanwhile, the high level of KatG in mc251 was accompanied by a low level of ATP, which meant that mc251 is at a low respiratory level. Additionally, the redox-related protein Rv1996 showed different phenotypes in different specific redox states in M. smegmatis mc2155 and mc251, M. bovis BCG, and M. tuberculosis mc27000. In conclusion, our study shows that the same gene presents different phenotypes under different physiological conditions. This may partly explain why M. smegmatis and M. tuberculosis have similar virulence factors and signaling transduction systems such as two-component systems and sigma factors, but due to the different redox states in the corresponding bacteria, M. smegmatis is a nonpathogen, while M. tuberculosis is a pathogen. As mc251 overcomes its shortcomings of rapid removal, it can potentially be developed as a vaccine vector.
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Affiliation(s)
- Zheng Jiang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Zengfang Zhuang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Kaixia Mi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
- *Correspondence: Kaixia Mi,
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21
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Gupta KR, Arora G, Mattoo A, Sajid A. Stringent Response in Mycobacteria: From Biology to Therapeutic Potential. Pathogens 2021; 10:pathogens10111417. [PMID: 34832573 PMCID: PMC8622095 DOI: 10.3390/pathogens10111417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/18/2021] [Accepted: 10/26/2021] [Indexed: 01/16/2023] Open
Abstract
Mycobacterium tuberculosis is a human pathogen that can thrive inside the host immune cells for several years and cause tuberculosis. This is due to the propensity of M. tuberculosis to synthesize a sturdy cell wall, shift metabolism and growth, secrete virulence factors to manipulate host immunity, and exhibit stringent response. These attributes help M. tuberculosis to manage the host response, and successfully establish and maintain an infection even under nutrient-deprived stress conditions for years. In this review, we will discuss the importance of mycobacterial stringent response under different stress conditions. The stringent response is mediated through small signaling molecules called alarmones “(pp)pGpp”. The synthesis and degradation of these alarmones in mycobacteria are mediated by Rel protein, which is both (p)ppGpp synthetase and hydrolase. Rel is important for all central dogma processes—DNA replication, transcription, and translation—in addition to regulating virulence, drug resistance, and biofilm formation. Rel also plays an important role in the latent infection of M. tuberculosis. Here, we have discussed the literature on alarmones and Rel proteins in mycobacteria and highlight that (p)ppGpp-analogs and Rel inhibitors could be designed and used as antimycobacterial compounds against M. tuberculosis and non-tuberculous mycobacterial infections.
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Affiliation(s)
| | - Gunjan Arora
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA;
| | - Abid Mattoo
- Pharmaceutical Development, Ultragenyx Gene Therapy, Woburn, MA 01801, USA;
| | - Andaleeb Sajid
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA;
- Correspondence: or
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22
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Danchik C, Wang S, Karakousis PC. Targeting the Mycobacterium tuberculosis Stringent Response as a Strategy for Shortening Tuberculosis Treatment. Front Microbiol 2021; 12:744167. [PMID: 34690990 PMCID: PMC8529327 DOI: 10.3389/fmicb.2021.744167] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 09/14/2021] [Indexed: 11/13/2022] Open
Abstract
The stringent response is well conserved across bacterial species and is a key pathway involved both in bacterial survival and virulence and in the induction of antibiotic tolerance in Mycobacteria. It is mediated by the alarmone (p)ppGpp and the regulatory molecule inorganic polyphosphate in response to stress conditions such as nutrient starvation. Efforts to pharmacologically target various components of the stringent response have shown promise in modulating mycobacterial virulence and antibiotic tolerance. In this review, we summarize the current understanding of the stringent response and its role in virulence and tolerance in Mycobacteria, including evidence that targeting this pathway could have therapeutic benefit.
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Affiliation(s)
| | | | - Petros C. Karakousis
- Division of Infectious Diseases, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, United States
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23
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Chaperone-Mediated Stress Sensing in Mycobacterium tuberculosis Enables Fast Activation and Sustained Response. mSystems 2021; 6:6/1/e00979-20. [PMID: 33594002 PMCID: PMC8561658 DOI: 10.1128/msystems.00979-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dynamical properties of gene regulatory networks are tuned to ensure bacterial survival. In mycobacteria, the MprAB-σE network responds to the presence of stressors, such as surfactants that cause surface stress. Positive feedback loops in this network were previously predicted to cause hysteresis, i.e., different responses to identical stressor levels for prestressed and unstressed cells. Here, we show that hysteresis does not occur in nonpathogenic Mycobacterium smegmatis but does occur in Mycobacterium tuberculosis However, the observed rapid temporal response in M. tuberculosis is inconsistent with the model predictions. To reconcile these observations, we implement a recently proposed mechanism for stress sensing, namely, the release of MprB from the inhibitory complex with the chaperone DnaK upon the stress exposure. Using modeling and parameter fitting, we demonstrate that this mechanism can accurately describe the experimental observations. Furthermore, we predict perturbations in DnaK expression that can strongly affect dynamical properties. Experiments with these perturbations agree with model predictions, confirming the role of DnaK in fast and sustained response.IMPORTANCE Gene regulatory networks controlling stress response in mycobacterial species have been linked to persistence switches that enable bacterial dormancy within a host. However, the mechanistic basis of switching and stress sensing is not fully understood. In this paper, combining quantitative experiments and mathematical modeling, we uncover how interactions between two master regulators of stress response-the MprAB two-component system (TCS) and the alternative sigma factor σE-shape the dynamical properties of the surface stress network. The result show hysteresis (history dependence) in the response of the pathogenic bacterium M. tuberculosis to surface stress and lack of hysteresis in nonpathogenic M. smegmatis Furthermore, to resolve the apparent contradiction between the existence of hysteresis and fast activation of the response, we utilize a recently proposed role of chaperone DnaK in stress sensing. These result leads to a novel system-level understanding of bacterial stress response dynamics.
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Polyphosphate is an extracellular signal that can facilitate bacterial survival in eukaryotic cells. Proc Natl Acad Sci U S A 2020; 117:31923-31934. [PMID: 33268492 DOI: 10.1073/pnas.2012009117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Polyphosphate is a linear chain of phosphate residues and is present in organisms ranging from bacteria to humans. Pathogens such as Mycobacterium tuberculosis accumulate polyphosphate, and reduced expression of the polyphosphate kinase that synthesizes polyphosphate decreases their survival. How polyphosphate potentiates pathogenicity is poorly understood. Escherichia coli K-12 do not accumulate detectable levels of extracellular polyphosphate and have poor survival after phagocytosis by Dictyostelium discoideum or human macrophages. In contrast, Mycobacterium smegmatis and Mycobacterium tuberculosis accumulate detectable levels of extracellular polyphosphate, and have relatively better survival after phagocytosis by D. discoideum or macrophages. Adding extracellular polyphosphate increased E. coli survival after phagocytosis by D. discoideum and macrophages. Reducing expression of polyphosphate kinase 1 in M. smegmatis reduced extracellular polyphosphate and reduced survival in D. discoideum and macrophages, and this was reversed by the addition of extracellular polyphosphate. Conversely, treatment of D. discoideum and macrophages with recombinant yeast exopolyphosphatase reduced the survival of phagocytosed M. smegmatis or M. tuberculosis D. discoideum cells lacking the putative polyphosphate receptor GrlD had reduced sensitivity to polyphosphate and, compared to wild-type cells, showed increased killing of phagocytosed E. coli and M. smegmatis Polyphosphate inhibited phagosome acidification and lysosome activity in D. discoideum and macrophages and reduced early endosomal markers in macrophages. Together, these results suggest that bacterial polyphosphate potentiates pathogenicity by acting as an extracellular signal that inhibits phagosome maturation.
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Boldrin F, Provvedi R, Cioetto Mazzabò L, Segafreddo G, Manganelli R. Tolerance and Persistence to Drugs: A Main Challenge in the Fight Against Mycobacterium tuberculosis. Front Microbiol 2020; 11:1924. [PMID: 32983003 PMCID: PMC7479264 DOI: 10.3389/fmicb.2020.01924] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 07/21/2020] [Indexed: 12/18/2022] Open
Abstract
The treatment of tuberculosis is extremely long. One of the reasons why Mycobacterium tuberculosis elimination from the organism takes so long is that in particular environmental conditions it can become tolerant to drugs and/or develop persisters able to survive killing even from very high drug concentrations. Tolerance develops in response to a harsh environment exposure encountered by bacteria during infection, mainly due to the action of the immune system, whereas persistence results from the presence of heterogeneous bacterial populations with different degrees of drug sensitivity, and can be induced by exposure to stress conditions. Here, we review the actual knowledge on the stress response mechanisms enacted by M. tuberculosis during infection, which leads to increased drug tolerance or development of a highly drug-resistant subpopulation.
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Affiliation(s)
- Francesca Boldrin
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | | | | | - Greta Segafreddo
- Department of Molecular Medicine, University of Padova, Padova, Italy
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Rang J, He H, Chen J, Hu J, Tang J, Liu Z, Xia Z, Ding X, Zhang Y, Xia L. SenX3-RegX3, an Important Two-Component System, Regulates Strain Growth and Butenyl-spinosyn Biosynthesis in Saccharopolyspora pogona. iScience 2020; 23:101398. [PMID: 32768668 PMCID: PMC7414002 DOI: 10.1016/j.isci.2020.101398] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 06/09/2020] [Accepted: 07/20/2020] [Indexed: 01/31/2023] Open
Abstract
Butenyl-spinosyn produced by Saccharopolyspora pogona exhibits strong insecticidal activity and a broad pesticidal spectrum. Currently, important functional genes involved in butenyl-spinosyn biosynthesis remain unknown, which leads to difficulty in efficient understanding of its regulatory mechanism and improving its production by metabolic engineering. Here, we present data supporting a role of the SenX3-RegX3 system in regulating the butenyl-spinosyn biosynthesis. EMSAs and qRT-PCR demonstrated that RegX3 positively controls butenyl-spinosyn production in an indirect way. Integrated proteomic and metabolomic analysis, regX3 deletion not only strengthens the basal metabolic ability of S. pogona in the mid-growth phase but also promotes the flow of the acetyl-CoA produced via key metabolic pathways into the TCA cycle rather than the butenyl-spinosyn biosynthetic pathway, which ultimately leads to continued growth but reduced butenyl-spinosyn production. The strategy demonstrated here may be valuable for revealing the regulatory role of the SenX3-RegX3 system in the biosynthesis of other natural products. Butenyl-spinosyn biosynthesis is highly sensitive to Pi control RegX3 regulates polyP accumulation in S. pogona RegX3 may indirectly regulate butenyl-spinosyn production RegX3 plays an important role in the normal growth development of S. pogona
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Affiliation(s)
- Jie Rang
- State Key Laboratory of Development Biology of Freshwater Fish, Hunan Provincial Key Laboratory for Microbial Molecular Biology, College of Life Science, Hunan Normal University, 410081 Changsha, China
| | - Haocheng He
- State Key Laboratory of Development Biology of Freshwater Fish, Hunan Provincial Key Laboratory for Microbial Molecular Biology, College of Life Science, Hunan Normal University, 410081 Changsha, China
| | - Jianming Chen
- State Key Laboratory of Development Biology of Freshwater Fish, Hunan Provincial Key Laboratory for Microbial Molecular Biology, College of Life Science, Hunan Normal University, 410081 Changsha, China
| | - Jinjuan Hu
- State Key Laboratory of Development Biology of Freshwater Fish, Hunan Provincial Key Laboratory for Microbial Molecular Biology, College of Life Science, Hunan Normal University, 410081 Changsha, China
| | - Jianli Tang
- State Key Laboratory of Development Biology of Freshwater Fish, Hunan Provincial Key Laboratory for Microbial Molecular Biology, College of Life Science, Hunan Normal University, 410081 Changsha, China
| | - Zhudong Liu
- State Key Laboratory of Development Biology of Freshwater Fish, Hunan Provincial Key Laboratory for Microbial Molecular Biology, College of Life Science, Hunan Normal University, 410081 Changsha, China
| | - Ziyuan Xia
- State Key Laboratory of Development Biology of Freshwater Fish, Hunan Provincial Key Laboratory for Microbial Molecular Biology, College of Life Science, Hunan Normal University, 410081 Changsha, China
| | - Xuezhi Ding
- State Key Laboratory of Development Biology of Freshwater Fish, Hunan Provincial Key Laboratory for Microbial Molecular Biology, College of Life Science, Hunan Normal University, 410081 Changsha, China
| | - Youming Zhang
- State Key Laboratory of Development Biology of Freshwater Fish, Hunan Provincial Key Laboratory for Microbial Molecular Biology, College of Life Science, Hunan Normal University, 410081 Changsha, China
| | - Liqiu Xia
- State Key Laboratory of Development Biology of Freshwater Fish, Hunan Provincial Key Laboratory for Microbial Molecular Biology, College of Life Science, Hunan Normal University, 410081 Changsha, China.
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27
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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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28
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Chuang YM, Dutta NK, Gordy JT, Campodónico VL, Pinn ML, Markham RB, Hung CF, Karakousis PC. Antibiotic Treatment Shapes the Antigenic Environment During Chronic TB Infection, Offering Novel Targets for Therapeutic Vaccination. Front Immunol 2020; 11:680. [PMID: 32411131 PMCID: PMC7198710 DOI: 10.3389/fimmu.2020.00680] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 03/26/2020] [Indexed: 12/03/2022] Open
Abstract
The lengthy and complicated current regimen required to treat drug-susceptible tuberculosis (TB) reflects the ability of Mycobacterium tuberculosis (Mtb) to persist in host tissues. The stringent response pathway, governed by the dual (p)ppGpp synthetase/hydrolase, RelMtb, is a major mechanism underlying Mtb persistence and antibiotic tolerance. In the current study, we addressed the hypothesis that RelMtb is a “persistence antigen” presented during TB chemotherapy and that enhanced immunity to RelMtb can enhance the tuberculocidal activity of the first-line anti-TB drug, isoniazid, which has reduced efficacy against Mtb persisters. C57BL/6 mice and Hartley guinea pigs were aerosol-infected with M. tuberculosis (Mtb) and, 4 weeks later, received either human-equivalent daily doses of isoniazid alone, or isoniazid in combination with a DNA vaccine targeting relMtb. After isoniazid treatment, there was a significant reduction in dominant antigen ESAT6-reactive CD4+ or TB10.4-reactive CD8+ T cells in the lungs and spleens of mice. However, the total number of RelMtb-reactive CD4+ T cells remained stable in mouse lungs and spleens, as did the number of RelMtb-reactive CD8+T cells. Therapeutic vaccination with relMtb DNA vaccine enhanced the activity of isoniazid in Mtb-infected C57BL/6 mice and guinea pigs. When treatment with isoniazid was discontinued, mice immunized with the relMtb DNA vaccine showed a lower mean lung bacterial burden at relapse compared to the control group. Our work shows that antitubercular treatment shapes the antigenic environment, and that therapeutic vaccination targeting the Mtb stringent response may represent a novel approach to enhance immunity against Mtb persisters, with the ultimate goal of shortening curative TB treatment.
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Affiliation(s)
- Yu-Min Chuang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Noton K Dutta
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - James T Gordy
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Victoria L Campodónico
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Michael L Pinn
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Richard B Markham
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Chien-Fu Hung
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Petros C Karakousis
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States.,Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
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29
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Irving SE, Corrigan RM. Triggering the stringent response: signals responsible for activating (p)ppGpp synthesis in bacteria. MICROBIOLOGY-SGM 2019; 164:268-276. [PMID: 29493495 DOI: 10.1099/mic.0.000621] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The stringent response is a conserved bacterial stress response mechanism that allows bacteria to respond to nutritional challenges. It is mediated by the alarmones pppGpp and ppGpp, nucleotides that are synthesized and hydrolyzed by members of the RSH superfamily. Whilst there are key differences in the binding targets for (p)ppGpp between Gram-negative and Gram-positive bacterial species, the transient accumulation of (p)ppGpp caused by nutritional stresses results in a global change in gene expression in all species. The RSH superfamily of enzymes is ubiquitous throughout the bacterial kingdom, and can be split into three main groups: the long-RSH enzymes; the small alarmone synthetases (SAS); and the small alarmone hydrolases (SAH). Despite the prevalence of these enzymes, there are important differences in the way in which they are regulated on a transcriptional and post-translational level. Here we provide an overview of the diverse regulatory mechanisms that are involved in governing this crucial signalling network. Understanding how the RSH superfamily members are regulated gives insights into the varied important biological roles for this signalling pathway across the bacteria.
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Affiliation(s)
- Sophie E Irving
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, UK
| | - Rebecca M Corrigan
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, UK
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30
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Vilchèze C, Jacobs WR. The Isoniazid Paradigm of Killing, Resistance, and Persistence in Mycobacterium tuberculosis. J Mol Biol 2019; 431:3450-3461. [PMID: 30797860 PMCID: PMC6703971 DOI: 10.1016/j.jmb.2019.02.016] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 02/05/2019] [Accepted: 02/11/2019] [Indexed: 12/20/2022]
Abstract
Isoniazid (INH) was the first synthesized drug that mediated bactericidal killing of the bacterium Mycobacterium tuberculosis, a major clinical breakthrough. To this day, INH remains a cornerstone of modern tuberculosis (TB) chemotherapy. This review describes the serendipitous discovery of INH, its effectiveness on TB patients, and early studies to discover its mechanisms of bacteriocidal activity. Forty years after its introduction as a TB drug, the development of gene transfer in mycobacteria enabled the discovery of the genes encoding INH resistance, namely, the activator (katG) and the target (inhA) of INH. Further biochemical and x-ray crystallography studies on KatG and InhA proteins and mutants provided comprehensive understanding of INH mode of action and resistance mechanisms. Bacterial cultures can harbor subpopulations that are genetically or phenotypically resistant cells, the latter known as persisters. Treatment of exponentially growing cultures of M. tuberculosis with INH reproducibly kills 99% to 99.9% of cells in 3 days. Importantly, the surviving cells are slowly replicating or non-replicating cells expressing a unique stress response signature: these are the persisters. These persisters can be visualized using dual-reporter mycobacteriophages and their formation prevented using reducing compounds, such as N-acetylcysteine or vitamin C, that enhance M. tuberculosis' respiration. Altogether, this review portrays a detailed molecular analysis of INH killing and resistance mechanisms including persistence. The phenomenon of persistence is clearly the single greatest impediment to TB control, and research aimed at understanding persistence will provide new strategies to improve TB chemotherapy.
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Affiliation(s)
- Catherine Vilchèze
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1301 Morris Park Avenue, Bronx, NY 10461, USA
| | - William R Jacobs
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1301 Morris Park Avenue, Bronx, NY 10461, USA.
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31
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Zhu J, Liu R, Cao N, Yu J, Liu X, Yu Z. Mycobacterial metabolic characteristics in a water meter biofilm revealed by metagenomics and metatranscriptomics. WATER RESEARCH 2019; 153:315-323. [PMID: 30739073 DOI: 10.1016/j.watres.2019.01.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 12/27/2018] [Accepted: 01/28/2019] [Indexed: 06/09/2023]
Abstract
Mycobacteria represent one of the most persistent bacterial populations in drinking water distribution system (DWDS) biofilm communities; however, mycobacterial in situ metabolic profiles are largely unknown. In this study, the metabolic characteristics of mycobacteria in a household water meter biofilm were unveiled using a coupled metagenomic/metatranscriptomic approach. The water meter biofilm appeared to express nitrogenase genes (nifDKH) and a full complement of genes coding for several carbon-fixation pathways, especially the Calvin cycle, suggesting the CO2 sequestration and dinitrogen fixation potential of the biofilm. These findings indicate that it may be difficult to prevent the formation of DWDS biofilms simply by controlling the availability of organic carbon or nitrogen. The composite genome of mycobacteria (CG-M) was reconstructed based on the obtained omics data. CG-M shared similar genome phylogeny and virulence-factor profiles with Mycobacterium avium complex, suggesting that population CG-M might represent a member of mycobacteria with pathogenicity. According to the gene expression patterns, population CG-M showed the metabolic potential to assimilate CO2 via the Calvin cycle and/or anaplerotic reactions, and even to grow autotrophically with CO as the sole carbon and energy source. This suggests that organic carbon may not be a limiting factor for mycobacterial growth in DWDSs. Moreover, our results suggest that mycobacterial aromatic degradation is primarily achieved through the catechol meta-cleavage pathway, and biofilm mycobacteria could prefer phosphate as the phosphorus source.
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Affiliation(s)
- Junge Zhu
- University of Chinese Academy of Sciences, Beijing, China; Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Ruyin Liu
- University of Chinese Academy of Sciences, Beijing, China.
| | - Nan Cao
- Beijing Waterworks Group, Beijing, China
| | - Jianwei Yu
- Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Xinchun Liu
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhisheng Yu
- University of Chinese Academy of Sciences, Beijing, China
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32
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Inorganic Polyphosphate Accumulation in Escherichia coli Is Regulated by DksA but Not by (p)ppGpp. J Bacteriol 2019; 201:JB.00664-18. [PMID: 30745375 DOI: 10.1128/jb.00664-18] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 02/07/2019] [Indexed: 12/25/2022] Open
Abstract
Production of inorganic polyphosphate (polyP) by bacteria is triggered by a variety of different stress conditions. polyP is required for stress survival and virulence in diverse pathogenic microbes. Previous studies have hypothesized a model for regulation of polyP synthesis in which production of the stringent-response second messenger (p)ppGpp directly stimulates polyP accumulation. In this work, I have now shown that this model is incorrect, and (p)ppGpp is not required for polyP synthesis in Escherichia coli However, stringent mutations of RNA polymerase that frequently arise spontaneously in strains defective in (p)ppGpp synthesis and null mutations of the stringent-response-associated transcription factor DksA both strongly inhibit polyP accumulation. The loss of polyP synthesis in a mutant lacking DksA was reversed by deletion of the transcription elongation factor GreA, suggesting that competition between these proteins for binding to the secondary channel of RNA polymerase plays an important role in controlling polyP activation. These results provide new insights into the poorly understood regulation of polyP synthesis in bacteria and indicate that the relationship between polyP and the stringent response is more complex than previously suspected.IMPORTANCE Production of polyP in bacteria is required for virulence and stress response, but little is known about how bacteria regulate polyP levels in response to changes in their environments. Understanding this regulation is important for understanding how pathogenic microbes resist killing by disinfectants, antibiotics, and the immune system. In this work, I have clarified the connections between polyP regulation and the stringent response to starvation stress in Escherichia coli and demonstrated an important and previously unknown role for the transcription factor DksA in controlling polyP levels.
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Dutta NK, Klinkenberg LG, Vazquez MJ, Segura-Carro D, Colmenarejo G, Ramon F, Rodriguez-Miquel B, Mata-Cantero L, Porras-De Francisco E, Chuang YM, Rubin H, Lee JJ, Eoh H, Bader JS, Perez-Herran E, Mendoza-Losana A, Karakousis PC. Inhibiting the stringent response blocks Mycobacterium tuberculosis entry into quiescence and reduces persistence. SCIENCE ADVANCES 2019; 5:eaav2104. [PMID: 30906866 PMCID: PMC6426458 DOI: 10.1126/sciadv.aav2104] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 02/04/2019] [Indexed: 06/01/2023]
Abstract
The stringent response enables Mycobacterium tuberculosis (Mtb) to shut down its replication and metabolism under various stresses. Here we show that Mtb lacking the stringent response enzyme RelMtb was unable to slow its replication rate during nutrient starvation. Metabolomics analysis revealed that the nutrient-starved relMtb -deficient strain had increased metabolism similar to that of exponentially growing wild-type bacteria in nutrient-rich broth, consistent with an inability to enter quiescence. Deficiency of relMtb increased the susceptibility of mutant bacteria to killing by isoniazid during nutrient starvation and in the lungs of chronically infected mice. We screened a pharmaceutical library of over 2 million compounds for inhibitors of RelMtb and showed that the lead compound X9 was able to directly kill nutrient-starved M. tuberculosis and enhanced the killing activity of isoniazid. Inhibition of RelMtb is a promising approach to target M. tuberculosis persisters, with the potential to shorten the duration of TB treatment.
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Affiliation(s)
- Noton K. Dutta
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lee G. Klinkenberg
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | | | - Gonzalo Colmenarejo
- Molecular Discovery Research, GlaxoSmithKline, Tres Cantos, Madrid, Spain
- Biostatistics and Bioinformatics Unit, IMDEA Food Institute, Madrid, Spain
| | - Fernando Ramon
- Molecular Discovery Research, GlaxoSmithKline, Tres Cantos, Madrid, Spain
| | | | - Lydia Mata-Cantero
- Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, Madrid, Spain
| | | | - Yu-Min Chuang
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Harvey Rubin
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jae Jin Lee
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of USC, Los Angeles, CA, USA
| | - Hyungjin Eoh
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of USC, Los Angeles, CA, USA
| | - Joel S. Bader
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Esther Perez-Herran
- Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, Madrid, Spain
| | | | - Petros C. Karakousis
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
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Gautam LK, Sharma P, Capalash N. Bacterial Polyphosphate Kinases Revisited: Role in Pathogenesis and Therapeutic Potential. Curr Drug Targets 2019; 20:292-301. [DOI: 10.2174/1389450119666180801120231] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 06/02/2018] [Accepted: 07/31/2018] [Indexed: 11/22/2022]
Abstract
Bacterial infections have always been an unrestrained challenge to the medical community due to the rise of multi-drug tolerant and resistant strains. Pioneering work on Escherichia coli polyphosphate kinase (PPK) by Arthur Kornberg has generated great interest in this polyphosphate (PolyP) synthesizing enzyme. PPK has wide distribution among pathogens and is involved in promoting pathogenesis, stress management and susceptibility to antibiotics. Further, the absence of a PPK orthologue in humans makes it a potential drug target. This review covers the functional and structural aspects of polyphosphate kinases in bacterial pathogens. A description of molecules being designed against PPKs has been provided, challenges associated with PPK inhibitor design are highlighted and the strategies to enable development of efficient drug against this enzyme have also been discussed.
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Affiliation(s)
- Lalit Kumar Gautam
- Department of Biotechnology, Panjab University, BMS Block-I, Sector- 25, Chandigarh, 160014, India
| | - Prince Sharma
- Department of Microbiology, Panjab University, BMS Block-I, Sector- 25, Chandigarh, 160014, India
| | - Neena Capalash
- Department of Biotechnology, Panjab University, BMS Block-I, Sector- 25, Chandigarh, 160014, India
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Sulfurimonas subgroup GD17 cells accumulate polyphosphate under fluctuating redox conditions in the Baltic Sea: possible implications for their ecology. ISME JOURNAL 2018; 13:482-493. [PMID: 30291329 DOI: 10.1038/s41396-018-0267-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 05/04/2018] [Accepted: 05/11/2018] [Indexed: 12/16/2022]
Abstract
The central Baltic Sea is characterized by a pelagic redox zone exhibiting high dark CO2 fixation rates below the chemocline. These rates are mainly driven by chemolithoautotrophic and denitrifying Sulfurimonas GD17 subgroup cells which are motile and fast-reacting r-strategists. Baltic Sea redox zones are unstable and a measurable overlap of nitrate and reduced sulfur, essential for chemosynthesis, is often only available on small scales and short times due to local mixing events. This raises the question of how GD17 cells gain access to electron donors or acceptors over longer term periods and under substrate deficiency. One possible answer is that GD17 cells store high-energy-containing polyphosphate during favorable nutrient conditions to survive periods of nutrient starvation. We used scanning electron microscopy with energy-dispersive X-ray spectroscopy to investigate potential substrate enrichments in single GD17 cells collected from Baltic Sea redox zones. More specific substrate enrichment features were identified in experiments using Sulfurimonas gotlandica GD1T, a GD17 representative. Sulfurimonas cells accumulated polyphosphate both in situ and in vitro. Combined genome and culture-dependent analyses suggest that polyphosphate serves as an energy reservoir to maintain cellular integrity at unfavorable substrate conditions. This redox-independent energy supply would be a precondition for sustaining the r-strategy lifestyle of GD17 and may represent a newly identified survival strategy for chemolithoautotrophic prokaryotes occupying eutrophic redox zones.
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36
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Essential Nucleoid Associated Protein mIHF (Rv1388) Controls Virulence and Housekeeping Genes in Mycobacterium tuberculosis. Sci Rep 2018; 8:14214. [PMID: 30242166 PMCID: PMC6155035 DOI: 10.1038/s41598-018-32340-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 07/20/2018] [Indexed: 12/14/2022] Open
Abstract
Tight control of gene expression is crucial for Mycobacterium tuberculosis to adapt to the changing environments encountered when infecting or exiting human cells. While three nucleoid associated proteins (NAPs) EspR, HupB and Lsr2 have been investigated, the role of a fourth, the mycobacterial integration host factor (mIHF), remains elusive. Here, we report a multidisciplinary functional analysis that exploits a conditional mIHF mutant. Gene silencing was bactericidal and resulted in elongated cells devoid of septa, with only one nucleoid. ChIP-sequencing identified 153 broad peaks distributed around the chromosome, which were often situated upstream of transcriptional start sites where EspR also bound. RNA-sequencing showed expression of 209 genes to be heavily affected upon mIHF depletion, including those for many tRNAs, DNA synthesis and virulence pathways. Consistent with NAP function, mIHF acts as a global regulator by directly and indirectly controlling genes required for pathogenesis and for housekeeping functions.
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37
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Novel MprA binding motifs in the phoP regulatory region in Mycobacterium tuberculosis. Tuberculosis (Edinb) 2018; 112:62-68. [PMID: 30205970 DOI: 10.1016/j.tube.2018.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 07/31/2018] [Accepted: 08/02/2018] [Indexed: 11/20/2022]
Abstract
MprAB and PhoPR are important two-component systems (TCSs) in Mycobacterium tuberculosis, and both regulate EspR, a key regulator of the ESX-1 secretion system. Although previous studies suggest that the response regulator PhoP does not directly regulate mprA, the interplay between MprAB and PhoPR remains unclear. In this study, we found that the response regulator MprA can bind to the phoP promoter. Four repeat motifs, D1-D4, constituting two predicted binding sites, were located in the region protected by MprA in DNA footprinting. D1-D4 lack the reported conserved MprA binding sequences, indicating that MprA can recognize a greater range of target sites. Interestingly, D1-D2 overlap a previously reported PhoP binding site, and mutation of D1-D2 inhibited PhoP binding, whereas the D3-D4 site, but not the D1-D2 site, was required for MprA binding. EMSA assays also suggest that MprA and PhoP compete to bind to the phoP promoter. The results of the transcriptional and western blot assays are consistent with a model in which MprA positively controls the phoP expression, which in turn upregulates the expression of espR. These findings reveal complex regulation of a major mycobacterial TCS by dual TCSs.
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Bhaskar A, De Piano C, Gelman E, McKinney JD, Dhar N. Elucidating the role of (p)ppGpp in mycobacterial persistence against antibiotics. IUBMB Life 2018; 70:836-844. [PMID: 30092117 DOI: 10.1002/iub.1888] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 05/23/2018] [Indexed: 01/05/2023]
Abstract
Bacterial persistence, the ability of bacteria to survive high concentrations of antibiotics for extended periods of time, is an important contributing factor to therapy failure and development of chronic and recurrent infections. Several recent studies have suggested that this persistence is mediated primarily by (p)ppGpp, through its interactions with toxin-antitoxin modules and polyphosphates. In this study, we address whether these key players play a role in mycobacterial persistence against antibiotics. We targeted these specific pathways in Mycobacterium smegmatis by constructing deletion strains of (p)ppGpp synthetase/hydrolase (relA), polyphosphate kinases (ppk1 and ppk2), exopolyphosphatases (ppx1 and ppx2), and the lon protease. None of these mutant strains exhibited altered levels of persisters against isoniazid and ciprofloxacin, when compared with wild-type strain. Even under conditions in which the stringent response usually gets activated, these strains displayed wild-type persister levels. Interestingly, we also found that unlike Escherichia coli, maintaining M. smegmatis in exponential phase by repeated passaging does not eliminate persisters suggesting that at least against the antibiotics tested, stationary-phase dependent persisters (type I) are not the major contributors. Thus, our data demonstrate that multiple mechanisms of antibiotic persistence exist and that these vary widely among different bacterial species. © 2018 IUBMB Life, 70(9):836-844, 2018.
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Affiliation(s)
- Ashima Bhaskar
- Laboratory of Microbiology and Microtechnology, School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), Lausanne, Switzerland
| | - Cyntia De Piano
- Laboratory of Microbiology and Microtechnology, School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), Lausanne, Switzerland
| | - Ekaterina Gelman
- Laboratory of Microbiology and Microtechnology, School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), Lausanne, Switzerland
| | - John D McKinney
- Laboratory of Microbiology and Microtechnology, School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), Lausanne, Switzerland
| | - Neeraj Dhar
- Laboratory of Microbiology and Microtechnology, School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), Lausanne, Switzerland
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Incipient and Subclinical Tuberculosis: a Clinical Review of Early Stages and Progression of Infection. Clin Microbiol Rev 2018; 31:31/4/e00021-18. [PMID: 30021818 DOI: 10.1128/cmr.00021-18] [Citation(s) in RCA: 303] [Impact Index Per Article: 50.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Tuberculosis (TB) is the leading infectious cause of mortality worldwide, due in part to a limited understanding of its clinical pathogenic spectrum of infection and disease. Historically, scientific research, diagnostic testing, and drug treatment have focused on addressing one of two disease states: latent TB infection or active TB disease. Recent research has clearly demonstrated that human TB infection, from latent infection to active disease, exists within a continuous spectrum of metabolic bacterial activity and antagonistic immunological responses. This revised understanding leads us to propose two additional clinical states: incipient and subclinical TB. The recognition of incipient and subclinical TB, which helps divide latent and active TB along the clinical disease spectrum, provides opportunities for the development of diagnostic and therapeutic interventions to prevent progression to active TB disease and transmission of TB bacilli. In this report, we review the current understanding of the pathogenesis, immunology, clinical epidemiology, diagnosis, treatment, and prevention of both incipient and subclinical TB, two emerging clinical states of an ancient bacterium.
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Prusa J, Zhu DX, Stallings CL. The stringent response and Mycobacterium tuberculosis pathogenesis. Pathog Dis 2018; 76:5035815. [PMID: 29947752 PMCID: PMC7191866 DOI: 10.1093/femspd/fty054] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 06/08/2018] [Indexed: 12/23/2022] Open
Abstract
During infection, the host restrains Mycobacterium tuberculosis (Mtb) from proliferating by imposing an arsenal of stresses. Despite this onslaught of attacks, Mtb is able to persist for the lifetime of the host, indicating that this pathogen has substantial molecular mechanisms to resist host-inflicted damage. The stringent response is a conserved global stress response in bacteria that involves the production of the hyperphosphorylated guanine nucleotides ppGpp and pppGpp (collectively called (p)ppGpp). (p)ppGpp then regulates a number of cellular processes to adjust the physiology of the bacteria to promote survival in different environments. Survival in the presence of host-generated stresses is an essential quality of successful pathogens, and the stringent response is critical for the intracellular survival of a number of pathogenic bacteria. In addition, the stringent response has been linked to virulence gene expression, persistence, latency and drug tolerance. In Mtb, (p)ppGpp synthesis is required for survival in low nutrient conditions, long term culture and during chronic infection in animal models, all indicative of a strict requirement for (p)ppGpp during exposure to stresses associated with infection. In this review we discuss (p)ppGpp metabolism and how this functions as a critical regulator of Mtb virulence.
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Affiliation(s)
- Jerome Prusa
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Dennis X Zhu
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Christina L Stallings
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
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Kundu M. The role of two-component systems in the physiology of Mycobacterium tuberculosis. IUBMB Life 2018; 70:710-717. [PMID: 29885211 DOI: 10.1002/iub.1872] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 04/22/2018] [Indexed: 12/14/2022]
Abstract
Tuberculosis is a global health problem, with a third of the world's population infected with the bacillus, Mycobacterium tuberculosis. The problem is exacerbated by the emergence of multidrug resistant and extensively drug resistant strains. The search for new drug targets is therefore a priority for researchers in the field. The two-component systems (TCSs) are central to the ability of the bacterium to sense and to respond appropriately to its environment. Here we summarize current knowledge on the paired TCSs of M. tuberculosis. We discuss what is currently understood regarding the signals to which each of the sensor kinases responds, and the regulons of each of the cognate response regulators. We also discuss what is known regarding attempts to inhibit the TCSs by small molecules and project their potential as pharmacological targets for the development of novel antimycobacterial agents. © 2018 IUBMB Life, 70(8):710-717, 2018.
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Wang Z, Cumming BM, Mao C, Zhu Y, Lu P, Steyn AJC, Chen S, Hu Y. RbpA and σ B association regulates polyphosphate levels to modulate mycobacterial isoniazid-tolerance. Mol Microbiol 2018; 108:627-640. [PMID: 29575247 DOI: 10.1111/mmi.13952] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2018] [Indexed: 12/13/2022]
Abstract
To facilitate survival under drug stresses, a small population of Mycobacterium tuberculosis can tolerate bactericidal concentrations of drugs without genetic mutations. These drug-tolerant mycobacteria can be induced by environmental stresses and contribute to recalcitrant infections. However, mechanisms underlying the development of drug-tolerant mycobacteria remain obscure. Herein, we characterized a regulatory pathway which is important for the tolerance to isoniazid (INH) in Mycobacterium smegmatis. We found that the RNA polymerase binding protein RbpA associates with the stress response sigma factor σB , to activate the transcription of ppk1, the gene encoding polyphosphate kinase. Subsequently, intracellular levels of inorganic polyphosphate increase to promote INH-tolerant mycobacteria. Interestingly, σB and ppk1 expression varied proportionately in mycobacterial populations and positively correlated with tolerance to INH in individual mycobacteria. Moreover, sigB and ppk1 transcription are both induced upon nutrient depletion, a condition that stimulates the formation of INH-tolerant mycobacteria. Over-expression of ppk1 in rbpA knockdown or sigB deleted strains successfully restored the number of INH-tolerant mycobacteria under both normal growth and nutrient starved conditions. These data suggest that RbpA and σB regulate ppk1 expression to control drug tolerance both during the logarithmic growth phase and under the nutrition starved conditions.
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Affiliation(s)
- Zhongwei Wang
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | | | - Chunyou Mao
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yan Zhu
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Pei Lu
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Adrie J C Steyn
- Africa Health Research Institute, Durban, South Africa.,Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Shiyun Chen
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Yangbo Hu
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
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Rudat AK, Pokhrel A, Green TJ, Gray MJ. Mutations in Escherichia coli Polyphosphate Kinase That Lead to Dramatically Increased In Vivo Polyphosphate Levels. J Bacteriol 2018; 200:e00697-17. [PMID: 29311274 PMCID: PMC5826030 DOI: 10.1128/jb.00697-17] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 12/20/2017] [Indexed: 11/20/2022] Open
Abstract
Bacteria synthesize inorganic polyphosphate (polyP) in response to a wide variety of stresses, and production of polyP is essential for stress response and survival in many important pathogens and bacteria used in biotechnological processes. However, surprisingly little is known about the molecular mechanisms that control polyP synthesis. We have therefore developed a novel genetic screen that specifically links growth of Escherichia coli to polyP synthesis, allowing us to isolate mutations leading to enhanced polyP production. Using this system, we have identified mutations in the polyP-synthesizing enzyme polyP kinase (PPK) that lead to dramatic increases in in vivo polyP synthesis but do not substantially affect the rate of polyP synthesis by PPK in vitro These mutations are distant from the PPK active site and found in interfaces between monomers of the PPK tetramer. We have also shown that high levels of polyP lead to intracellular magnesium starvation. Our results provide new insights into the control of bacterial polyP accumulation and suggest a simple, novel strategy for engineering bacteria with increased polyP contents.IMPORTANCE PolyP is an ancient, universally conserved biomolecule and is important for stress response, energy metabolism, and virulence in a remarkably broad range of microorganisms. PolyP accumulation by bacteria is also important in biotechnology applications. For example, it is critical to enhanced biological phosphate removal (EBPR) from wastewater. Understanding how bacteria control polyP synthesis is therefore of broad importance in both the fields of bacterial pathogenesis and biological engineering. Using Escherichia coli as a model organism, we have identified the first known mutations in polyP kinase that lead to increases in cellular polyP content.
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Affiliation(s)
- Amanda K Rudat
- Department of Microbiology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Arya Pokhrel
- Department of Microbiology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Todd J Green
- Department of Microbiology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Michael J Gray
- Department of Microbiology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Zondervan NA, van Dam JCJ, Schaap PJ, Martins Dos Santos VAP, Suarez-Diez M. Regulation of Three Virulence Strategies of Mycobacterium tuberculosis: A Success Story. Int J Mol Sci 2018; 19:E347. [PMID: 29364195 PMCID: PMC5855569 DOI: 10.3390/ijms19020347] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 01/19/2018] [Accepted: 01/21/2018] [Indexed: 12/28/2022] Open
Abstract
Tuberculosis remains one of the deadliest diseases. Emergence of drug-resistant and multidrug-resistant M. tuberculosis strains makes treating tuberculosis increasingly challenging. In order to develop novel intervention strategies, detailed understanding of the molecular mechanisms behind the success of this pathogen is required. Here, we review recent literature to provide a systems level overview of the molecular and cellular components involved in divalent metal homeostasis and their role in regulating the three main virulence strategies of M. tuberculosis: immune modulation, dormancy and phagosomal rupture. We provide a visual and modular overview of these components and their regulation. Our analysis identified a single regulatory cascade for these three virulence strategies that respond to limited availability of divalent metals in the phagosome.
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Affiliation(s)
- Niels A Zondervan
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Jesse C J van Dam
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Peter J Schaap
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Vitor A P Martins Dos Santos
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
- LifeGlimmer GmbH, Markelstrasse 38, 12163 Berlin, Germany.
| | - Maria Suarez-Diez
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
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Polyphosphate Kinase Antagonizes Virulence Gene Expression in Francisella tularensis. J Bacteriol 2018; 200:JB.00460-17. [PMID: 29158241 DOI: 10.1128/jb.00460-17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 11/02/2017] [Indexed: 12/31/2022] Open
Abstract
The alarmone ppGpp is a critical regulator of virulence gene expression in Francisella tularensis In this intracellular pathogen, ppGpp is thought to work in concert with the putative DNA-binding protein PigR and the SspA protein family members MglA and SspA to control a common set of genes. MglA and SspA form a complex that interacts with RNA polymerase (RNAP), and PigR functions by interacting with the RNAP-associated MglA-SspA complex. Prior work suggested that ppGpp indirectly exerts its regulatory effects in F. tularensis by promoting the accumulation of polyphosphate in the cell, which in turn was required for formation of the MglA-SspA complex. Here we show that in Escherichia coli, neither polyphosphate nor ppGpp is required for formation of the MglA-SspA complex but that ppGpp promotes the interaction between PigR and the MglA-SspA complex. Moreover, we show that polyphosphate kinase, the enzyme responsible for the synthesis of polyphosphate, antagonizes virulence gene expression in F. tularensis, a finding that is inconsistent with the notion that polyphosphate accumulation promotes virulence gene expression in this organism. Our findings identify polyphosphate kinase as a novel negative regulator of virulence gene expression in F. tularensis and support a model in which ppGpp exerts its positive regulatory effects by promoting the interaction between PigR and the MglA-SspA complex.IMPORTANCE In Francisella tularensis, MglA and SspA form a complex that associates with RNA polymerase to positively control the expression of key virulence genes. The MglA-SspA complex works together with the putative DNA-binding protein PigR and the alarmone ppGpp. PigR functions by interacting directly with the MglA-SspA complex, but how ppGpp exerts its effects was unclear. Prior work indicated that ppGpp acts by promoting the accumulation of polyphosphate, which is required for MglA and SspA to interact. Here we show that formation of the MglA-SspA complex does not require polyphosphate. Furthermore, we find that polyphosphate antagonizes the expression of virulence genes in F. tularensis Thus, ppGpp does not promote virulence gene expression in this organism through an effect on polyphosphate.
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New Approaches and Therapeutic Options for Mycobacterium tuberculosis in a Dormant State. Clin Microbiol Rev 2017; 31:31/1/e00060-17. [PMID: 29187395 DOI: 10.1128/cmr.00060-17] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We are far away from the days when tuberculosis (TB) accounted for 1 in 4 deaths during the 19th century. However, Mycobacterium tuberculosis complex (MTBC) strains are still the leading cause of morbidity and mortality by a single infectious disease, with 9.6 million cases and 1.5 million deaths reported. One-third of the world's population is estimated by the WHO to be infected with latent TB. During the last decade, several studies have aimed to define the characteristics of dormant bacteria in these latent infections. General features of the shift to a dormant state encompass several phenotypic changes that reduce metabolic activity. This low metabolic state is thought to increase the resistance of MTBC strains to host/environmental stresses, including antibiotic action. Once the stress ceases (e.g., interruption of treatment), dormant cells can reactivate and cause symptomatic disease again. Therefore, a proper understanding of dormancy could guide the rational development of new treatment regimens that target dormant cells, reducing later relapse. Here, we briefly summarize the latest data on the genetics involved in the regulation of dormancy and discuss new approaches to TB treatment.
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Abstract
Two-component systems are a dominant form of bacterial signal transduction. The prototypical two-component system consists of a sensor that responds to a specific input(s) by modifying the output of a cognate regulator. Because the output of a two-component system is the amount of phosphorylated regulator, feedback mechanisms may alter the amount of regulator, and/or modify the ability of a sensor or other proteins to alter the phosphorylation state of the regulator. Two-component systems may display intrinsic feedback whereby the amount of phosphorylated regulator changes under constant inducing conditions and without the participation of additional proteins. Feedback control allows a two-component system to achieve particular steady-state levels, to reach a given steady state with distinct dynamics, to express coregulated genes in a given order, and to activate a regulator to different extents, depending on the signal acting on the sensor.
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Affiliation(s)
- Eduardo A Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut 06536; .,Yale Microbial Sciences Institute, West Haven, Connecticut 06516
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48
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Monedero V, Revilla-Guarinos A, Zúñiga M. Physiological Role of Two-Component Signal Transduction Systems in Food-Associated Lactic Acid Bacteria. ADVANCES IN APPLIED MICROBIOLOGY 2017; 99:1-51. [PMID: 28438266 DOI: 10.1016/bs.aambs.2016.12.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Two-component systems (TCSs) are widespread signal transduction pathways mainly found in bacteria where they play a major role in adaptation to changing environmental conditions. TCSs generally consist of sensor histidine kinases that autophosphorylate in response to a specific stimulus and subsequently transfer the phosphate group to their cognate response regulators thus modulating their activity, usually as transcriptional regulators. In this review we present the current knowledge on the physiological role of TCSs in species of the families Lactobacillaceae and Leuconostocaceae of the group of lactic acid bacteria (LAB). LAB are microorganisms of great relevance for health and food production as the group spans from starter organisms to pathogens. Whereas the role of TCSs in pathogenic LAB (most of them belonging to the family Streptococcaceae) has focused the attention, the roles of TCSs in commensal LAB, such as most species of Lactobacillaceae and Leuconostocaceae, have been somewhat neglected. However, evidence available indicates that TCSs are key players in the regulation of the physiology of these bacteria. The first studies in food-associated LAB showed the involvement of some TCSs in quorum sensing and production of bacteriocins, but subsequent studies have shown that TCSs participate in other physiological processes, such as stress response, regulation of nitrogen metabolism, regulation of malate metabolism, and resistance to antimicrobial peptides, among others.
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Affiliation(s)
- Vicente Monedero
- Instituto de Agroquímica y Tecnología de Alimentos (CSIC), Paterna, Spain
| | | | - Manuel Zúñiga
- Instituto de Agroquímica y Tecnología de Alimentos (CSIC), Paterna, Spain
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49
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Varas M, Valdivieso C, Mauriaca C, Ortíz-Severín J, Paradela A, Poblete-Castro I, Cabrera R, Chávez FP. Multi-level evaluation of Escherichia coli polyphosphate related mutants using global transcriptomic, proteomic and phenomic analyses. Biochim Biophys Acta Gen Subj 2017; 1861:871-883. [PMID: 28069396 DOI: 10.1016/j.bbagen.2017.01.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 12/26/2016] [Accepted: 01/05/2017] [Indexed: 12/20/2022]
Abstract
BACKGROUND Polyphosphate (polyP) is a linear biopolymer found in all living cells. In bacteria, mutants lacking polyphosphate kinase 1 (PPK1), the enzyme responsible for synthesis of most polyP, have many structural and functional defects. However, little is known about the causes of these pleiotropic alterations. The link between ppk1 deletion and those numerous phenotypes observed can be the result of complex molecular interactions that can be elucidated via a systems biology approach. METHODS By integrating different omics levels (transcriptome, proteome and phenome), we described the functioning of various metabolic pathways among Escherichia coli polyphosphate mutant strains (Δppk1, Δppx, and ΔpolyP). Bioinformatic analyses reveal the complex metabolic and regulatory bases of the phenotypes unique to polyP mutants. RESULTS Our results suggest that during polyP deficiency (Δppk1 mutant), metabolic pathways needed for energy supply are up-regulated, including fermentation, aerobic and anaerobic respiration. Transcriptomic and q-proteomic contrasting changes between Δppk1 and Δppx mutant strains were observed in those central metabolic pathways and confirmed by using Phenotypic microarrays. In addition, our results suggest a regulatory connection between polyP, second messenger metabolism, alternative Sigma/Anti-Sigma factors and type-II toxin-antitoxin (TA) systems. CONCLUSIONS We suggest a broader role for polyP via regulation of ATP-dependent proteolysis of type II toxin-antitoxin system and alternative Sigma/Anti-Sigma factors, that could explain the multiple structural and functional deficiencies described due to alteration of polyP metabolism. GENERAL SIGNIFICANCE Understanding the interplay of polyP in bacterial metabolism using a systems biology approach can help to improve design of novel antimicrobials toward pathogens.
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Affiliation(s)
- Macarena Varas
- Systems Microbiology Laboratory, Department of Biology, Faculty of Science, University of Chile, Chile.
| | - Camilo Valdivieso
- Systems Microbiology Laboratory, Department of Biology, Faculty of Science, University of Chile, Chile; Department of Ecology, Faculty of Science, University of Chile, Chile.
| | - Cecilia Mauriaca
- Systems Microbiology Laboratory, Department of Biology, Faculty of Science, University of Chile, Chile.
| | - Javiera Ortíz-Severín
- Systems Microbiology Laboratory, Department of Biology, Faculty of Science, University of Chile, Chile.
| | | | - Ignacio Poblete-Castro
- Facultad de Ciencias Biológicas, Center for Bioinformatics and Integrative Biology, Biosystems Engineering Laboratory, Universidad Andrés Bello, Chile.
| | - Ricardo Cabrera
- Department of Biology, Faculty of Sciences, University of Chile, Chile.
| | - Francisco P Chávez
- Systems Microbiology Laboratory, Department of Biology, Faculty of Science, University of Chile, Chile.
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50
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Stringent Response Factors PPX1 and PPK2 Play an Important Role in Mycobacterium tuberculosis Metabolism, Biofilm Formation, and Sensitivity to Isoniazid In Vivo. Antimicrob Agents Chemother 2016; 60:6460-6470. [PMID: 27527086 DOI: 10.1128/aac.01139-16] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 08/09/2016] [Indexed: 01/30/2023] Open
Abstract
Mycobacterium tuberculosis remains a global health threat largely due to the lengthy duration of curative antibiotic treatment, contributing to medical nonadherence and the emergence of drug resistance. This prolonged therapy is likely due to the presence of M. tuberculosis persisters, which exhibit antibiotic tolerance. Inorganic polyphosphate [poly(P)] is a key regulatory molecule in the M. tuberculosis stringent response mediating antibiotic tolerance. The polyphosphate kinase PPK1 is responsible for poly(P) synthesis in M. tuberculosis, while the exopolyphosphatases PPX1 and PPX2 and the GTP synthase PPK2 are responsible for poly(P) hydrolysis. In the present study, we show by liquid chromatography-tandem mass spectrometry that poly(P)-accumulating M. tuberculosis mutant strains deficient in ppx1 or ppk2 had significantly lower intracellular levels of glycerol-3-phosphate (G3P) and 1-deoxy-xylulose-5-phosphate. Real-time PCR revealed decreased expression of genes in the G3P synthesis pathway in each mutant. The ppx1-deficient mutant also showed a significant accumulation of metabolites in the tricarboxylic acid cycle, as well as altered arginine and NADH metabolism. Each poly(P)-accumulating strain showed defective biofilm formation, while deficiency of ppk2 was associated with increased sensitivity to plumbagin and meropenem and deficiency of ppx1 led to enhanced susceptibility to clofazimine. A DNA vaccine expressing ppx1 and ppk2, together with two other members of the M. tuberculosis stringent response, M. tuberculosis rel and sigE, did not show protective activity against aerosol challenge with M. tuberculosis, but vaccine-induced immunity enhanced the killing activity of isoniazid in a murine model of chronic tuberculosis. In summary, poly(P)-regulating factors of the M. tuberculosis stringent response play an important role in M. tuberculosis metabolism, biofilm formation, and antibiotic sensitivity in vivo.
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