1
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Baek S, Lee EJ. PhoU: a multifaceted regulator in microbial signaling and homeostasis. Curr Opin Microbiol 2024; 77:102401. [PMID: 37988810 DOI: 10.1016/j.mib.2023.102401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 10/18/2023] [Accepted: 10/24/2023] [Indexed: 11/23/2023]
Abstract
Inorganic phosphate (Pi) is a fundamental molecule crucial for numerous biological processes, such as ATP synthesis and phospholipid formation. To prevent cellular toxicity, Pi transport is often linked to counterion transport within the bacterium. This review discusses the multifaceted functions of the PhoU protein in bacterial regulation, focusing on its role in coordinating Pi transport with counterions, controlling polyphosphate accumulation, and regulating secondary metabolite biosynthesis and DNA repair. We also explore recent findings that challenge the conventional view of PhoU simply as a negative regulator in phosphate signaling, suggesting its broader impact on bacterial physiology and stress response. Understanding the diverse functions of PhoU provides new insight into bacterial biology and offers potential therapeutic implications.
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Affiliation(s)
- Seungwoo Baek
- Department of Life Sciences, School of Life Sciences and Biotechnology, Korea University, Seoul, South Korea
| | - Eun-Jin Lee
- Department of Life Sciences, School of Life Sciences and Biotechnology, Korea University, Seoul, South Korea.
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2
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A Bibliometric Analysis of Research on Bacterial Persisters. BIOMED RESEARCH INTERNATIONAL 2023; 2023:4302914. [PMID: 36644164 PMCID: PMC9839416 DOI: 10.1155/2023/4302914] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 11/30/2022] [Accepted: 12/20/2022] [Indexed: 01/09/2023]
Abstract
Background In the past two decades, the surge of research on bacterial persisters has been inspired as increasingly concerning about the frequent failure of antibiotics treatment. This study was aimed at presenting a bibliometric and visualized analysis of relative publications on bacterial persisters, which offered insights into the development and research trends of this field. Methods The Web of Science Core Collection and Ovid MEDLINE databases were utilized to retrieve relevant publications on bacterial persisters from 2001 to 2021. After manual selection, data including titles, authors, journals, author keywords, addresses, the number of citations, and publication years were subsequently extracted. The data analysis and visual mapping were conducted with Excel, SPSS, R studio, and VOSviewer. Results In this study, 1,903 relevant publications on bacterial persisters were included. During 2001-2021, there was an exponential growth in the quantity of publications. It was found that these studies were conducted by 7,182 authors from 74 different countries. The USA led the scientific production with the highest total number of publications (859) and citation frequency (52,022). The Antimicrobial Agents and Chemotherapy was the most influential journal with 113 relevant publications. The cooccurrence analysis revealed that studies on bacterial persisters focused on four aspects: "the role of persisters in biofilms," "clinical persistent infection," "anti-persister treatment," and "mechanism of persister formation." Conclusion In the past two decades, the global field of bacterial persisters has significantly increased. The USA was the leading country in this field. Mechanistic studies continued to be the future hotspots, which may be helpful to adopt new strategies against persisters and solve the problem of chronic infection in the clinic.
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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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Kaushik V, Sharma S, Tiwari M, Tiwari V. Anti-persister strategies against stress induced bacterial persistence. Microb Pathog 2022; 164:105423. [PMID: 35092834 DOI: 10.1016/j.micpath.2022.105423] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 01/17/2022] [Accepted: 01/24/2022] [Indexed: 01/22/2023]
Abstract
The increase in antibiotic non-responsive bacteria is the leading concern in current research-oriented to eliminate pathogens. Nowadays, the excess use of antibiotics without specifically understanding the potentiality of killing pathogens and bacterial survival patterns has helped bacteria emerge indefatigably. Bacteria use various mechanisms such as resistance, persistence, and tolerance to ensure survival. Among these, persistence is a mechanism by which bacteria reside in their dormant state, bypassing the effects of treatments, making it crucial for bacterial survival. Persistent bacterial cells arise from the normal bacterial population as a slow-growing subset of bacteria with no metabolic flux. This behavior renders it to survive for a longer duration and at higher concentrations of antibiotics. They are one of the underlying causes of recurrence of bacterial infections. The present article explains the detailed molecular mechanisms and strategies of bacterial persistence, including the toxin-antitoxin modules, DNA damage, the formation of inactive ribosomal complexes, (p)ppGpp network, antibiotic-induced persistence, which are triggered by drug-induced stress. The article also comprehensively covers the epigenetic memory of persistence in bacteria, and anti-persistent therapeutics like antimicrobial molecules, synthetic peptides, acyldepsipeptide antibiotics, and endolysin therapy to reduce persister cell formation and control their frequency. These strategies could be utilized in combating the pathogenic bacteria undergoing persistence.
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Affiliation(s)
- Vaishali Kaushik
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India
| | - Saroj Sharma
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India.
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5
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Joshi H, Kandari D, Bhatnagar R. Insights into the molecular determinants involved in Mycobacterium tuberculosis persistence and their therapeutic implications. Virulence 2021; 12:2721-2749. [PMID: 34637683 PMCID: PMC8565819 DOI: 10.1080/21505594.2021.1990660] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/17/2021] [Accepted: 10/05/2021] [Indexed: 01/08/2023] Open
Abstract
The establishment of persistent infections and the reactivation of persistent bacteria to active bacilli are the two hurdles in effective tuberculosis treatment. Mycobacterium tuberculosis, an etiologic tuberculosis agent, adapts to numerous antibiotics and resists the host immune system causing a disease of public health concern. Extensive research has been employed to combat this disease due to its sheer ability to persist in the host system, undetected, waiting for the opportunity to declare itself. Persisters are a bacterial subpopulation that possesses transient tolerance to high doses of antibiotics. There are certain inherent mechanisms that facilitate the persister cell formation in Mycobacterium tuberculosis, some of those had been characterized in the past namely, stringent response, transcriptional regulators, energy production pathways, lipid metabolism, cell wall remodeling enzymes, phosphate metabolism, and proteasome protein degradation. This article reviews the recent advancements made in various in vitro persistence models that assist to unravel the mechanisms involved in the persister cell formation and to hunt for the possible preventive or treatment measures. To tackle the persister population the immunodominant proteins that express specifically at the latent phase of infection can be used for diagnosis to distinguish between the active and latent tuberculosis, as well as to select potential drug or vaccine candidates. In addition, we discuss the genes engaged in the persistence to get more insights into resuscitation and persister cell formation. The in-depth understanding of persistent cells of mycobacteria can certainly unravel novel ways to target the pathogen and tackle its persistence.
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Affiliation(s)
- Hemant Joshi
- Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Divya Kandari
- Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Rakesh Bhatnagar
- Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
- Amity University of Rajasthan, Jaipur, Rajasthan, India
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Tandem Mass Tag-Based Quantitative Proteomics and Virulence Phenotype of Hemolymph-Treated Bacillus thuringiensis kurstaki Cells Reveal New Insights on Bacterial Pathogenesis in Insects. Microbiol Spectr 2021; 9:e0060421. [PMID: 34704785 PMCID: PMC8549738 DOI: 10.1128/spectrum.00604-21] [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] [Indexed: 11/20/2022] Open
Abstract
The spore-forming bacterium Bacillus thuringiensis (Bt) of the Bacillus cereus group uses toxin-opened breaches at the insect midgut epithelium to infest the hemolymph, where it can rapidly propagate despite antimicrobial host defenses and induce host death by acute septicemia. The response of Bt to host hemolymph and the latter's role in bacterial pathogenesis is an area that needs clarification. Here, we report a proteomic analysis of the Bt kurstaki strain HD73 (Btk) hemolymph stimulon showing significant changes in 60 (34 up- and 26 downregulated) differentially accumulated proteins (DAPs). Gene ontology (GO) enrichment analysis revealed that DAPs were mainly related to glutamate metabolism, transketolase activity, and ATP-dependent transmembrane transport. KEGG analysis disclosed that DAPs were highly enriched in the biosynthesis of bacterial secondary metabolites, ansamycins. Interestingly, about 30% of all DAPs were in silico predicted as putative virulence factors. Further characterization of hemolymph effects on Btk showed enhanced autoaggregation in liquid cultures and biofilm formation in microtiter polystyrene plates. Hemolymph-exposed Btk cells were less immunogenic in mice, suggesting epitope masking of selected surface proteins. Bioassays with intrahemocoelically infected Bombyx mori larvae showed that hemolymph preexposure significantly increased Btk toxicity and reproduction within the insect (spore count per cadaver) at low inoculum doses, possibly due to 'virulence priming'. Collectively, our findings suggest that the Btk hemolymph stimulon could be partially responsible for bacterial survival and propagation within the hemolymph of infected insects, contributing to its remarkable success as an entomopathogen. All mass spectrometry data are available via ProteomeXchange with identifier PXD021830. IMPORTANCE After ingestion by a susceptible insect and damaging its midgut epithelium, the bacterium Bacillus thuringiensis (Bt) reaches the insect blood (hemolymph), where it propagates despite the host's antimicrobial defenses and induces insect death by acute septicemia. Although the hemolymph stage of the Bt toxic pathway is determinant for the infested insects' fate, the response of Bt to hemolymph and the latter's role in bacterial pathogenesis has been poorly explored. In this study, we identified the bacterial proteins differentially expressed by Bt after hemolymph exposure. We found that about 30% of hemolymph-regulated Bt proteins were potential virulence factors, including manganese superoxide dismutase, a described inhibitor of hemocyte respiratory burst. Additionally, contact with hemolymph enhanced Bt virulence phenotypes, such as cell aggregation and biofilm formation, altered bacterial immunogenicity, and increased Bt toxicity to intrahemocoelically injected insects.
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Padelli M, Aubron C, Huet O, Héry-Arnaud G, Vermeersch V, Hoffmann C, Bettacchioli É, Maguet H, Carré JL, Leven C. Is hypophosphataemia an independent predictor of mortality in critically ill patients with bloodstream infection? A multicenter retrospective cohort study. Aust Crit Care 2021; 34:47-54. [DOI: 10.1016/j.aucc.2020.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 05/04/2020] [Accepted: 05/05/2020] [Indexed: 12/28/2022] Open
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Arora G, Bothra A, Prosser G, Arora K, Sajid A. Role of post-translational modifications in the acquisition of drug resistance in Mycobacterium tuberculosis. FEBS J 2020; 288:3375-3393. [PMID: 33021056 DOI: 10.1111/febs.15582] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 09/16/2020] [Accepted: 09/30/2020] [Indexed: 12/22/2022]
Abstract
Tuberculosis (TB) is one of the primary causes of deaths due to infectious diseases. The current TB regimen is long and complex, failing of which leads to relapse and/or the emergence of drug resistance. There is a critical need to understand the mechanisms of resistance development. With increasing drug pressure, Mycobacterium tuberculosis (Mtb) activates various pathways to counter drug-related toxicity. Signaling modules steer the evolution of Mtb to a variant that can survive, persist, adapt, and emerge as a form that is resistant to one or more drugs. Recent studies reveal that about 1/3rd of the annotated Mtb proteome is modified post-translationally, with a large number of these proteins being essential for mycobacterial survival. Post-translational modifications (PTMs) such as phosphorylation, acetylation, and pupylation play a salient role in mycobacterial virulence, pathogenesis, and metabolism. The role of many other PTMs is still emerging. Understanding the signaling pathways and PTMs may assist clinical strategies and drug development for Mtb. In this review, we explore the contribution of PTMs to mycobacterial physiology, describe the related cellular processes, and discuss how these processes are linked to drug resistance. A significant number of drug targets, InhA, RpoB, EmbR, and KatG, are modified at multiple residues via PTMs. A better understanding of drug-resistance regulons and associated PTMs will aid in developing effective drugs against TB.
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Affiliation(s)
- Gunjan Arora
- Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Ankur Bothra
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Gareth Prosser
- Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park, UK
| | - Kriti Arora
- Proteus Digital Health, Inc., Redwood City, CA, USA
| | - Andaleeb Sajid
- Yale School of Medicine, Yale University, New Haven, CT, USA
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9
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Parker H, Lorenc R, Ruelas Castillo J, Karakousis PC. Mechanisms of Antibiotic Tolerance in Mycobacterium avium Complex: Lessons From Related Mycobacteria. Front Microbiol 2020; 11:573983. [PMID: 33101247 PMCID: PMC7554310 DOI: 10.3389/fmicb.2020.573983] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 09/01/2020] [Indexed: 11/13/2022] Open
Abstract
Mycobacterium avium complex (MAC) species are the most commonly isolated nontuberculous mycobacteria to cause pulmonary infections worldwide. The lengthy and complicated therapy required to cure lung disease due to MAC is at least in part due to the phenomenon of antibiotic tolerance. In this review, we will define antibiotic tolerance and contrast it with persistence and antibiotic resistance. We will discuss physiologically relevant stress conditions that induce altered metabolism and antibiotic tolerance in mycobacteria. Next, we will review general molecular mechanisms underlying bacterial antibiotic tolerance, particularly those described for MAC and related mycobacteria, including Mycobacterium tuberculosis, with a focus on genes containing significant sequence homology in MAC. An improved understanding of antibiotic tolerance mechanisms can lay the foundation for novel approaches to target antibiotic-tolerant mycobacteria, with the goal of shortening the duration of curative treatment and improving survival in patients with MAC.
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Affiliation(s)
- Harley Parker
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Rachel Lorenc
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Jennie Ruelas Castillo
- Department of Medicine, 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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10
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Salcedo-Sora JE, Kell DB. A Quantitative Survey of Bacterial Persistence in the Presence of Antibiotics: Towards Antipersister Antimicrobial Discovery. Antibiotics (Basel) 2020; 9:E508. [PMID: 32823501 PMCID: PMC7460088 DOI: 10.3390/antibiotics9080508] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/08/2020] [Accepted: 08/11/2020] [Indexed: 12/17/2022] Open
Abstract
Background: Bacterial persistence to antibiotics relates to the phenotypic ability to survive lethal concentrations of otherwise bactericidal antibiotics. The quantitative nature of the time-kill assay, which is the sector's standard for the study of antibiotic bacterial persistence, is an invaluable asset for global, unbiased, and cross-species analyses. Methods: We compiled the results of antibiotic persistence from antibiotic-sensitive bacteria during planktonic growth. The data were extracted from a sample of 187 publications over the last 50 years. The antibiotics used in this compilation were also compared in terms of structural similarity to fluorescent molecules known to accumulate in Escherichia coli. Results: We reviewed in detail data from 54 antibiotics and 36 bacterial species. Persistence varies widely as a function of the type of antibiotic (membrane-active antibiotics admit the fewest), the nature of the growth phase and medium (persistence is less common in exponential phase and rich media), and the Gram staining of the target organism (persistence is more common in Gram positives). Some antibiotics bear strong structural similarity to fluorophores known to be taken up by E. coli, potentially allowing competitive assays. Some antibiotics also, paradoxically, seem to allow more persisters at higher antibiotic concentrations. Conclusions: We consolidated an actionable knowledge base to support a rational development of antipersister antimicrobials. Persistence is seen as a step on the pathway to antimicrobial resistance, and we found no organisms that failed to exhibit it. Novel antibiotics need to have antipersister activity. Discovery strategies should include persister-specific approaches that could find antibiotics that preferably target the membrane structure and permeability of slow-growing cells.
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Affiliation(s)
- Jesus Enrique Salcedo-Sora
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Biosciences Building, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK;
| | - Douglas B. Kell
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Biosciences Building, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK;
- Novo Nordisk Foundation Centre for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800 Kgs. Lyngby, Denmark
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11
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Shang Y, Wang X, Chen Z, Lyu Z, Lin Z, Zheng J, Wu Y, Deng Q, Yu Z, Zhang Y, Qu D. Staphylococcus aureus PhoU Homologs Regulate Persister Formation and Virulence. Front Microbiol 2020; 11:865. [PMID: 32670206 PMCID: PMC7326077 DOI: 10.3389/fmicb.2020.00865] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 04/14/2020] [Indexed: 12/12/2022] Open
Abstract
PhoU homologs are one of the determinant factors in the regulation of persister formation and phosphate metabolism in many bacterial species; however, the functions of PhoU homologs exhibit species-specific characteristics. The pathogenesis of Staphylococcus aureus is closely correlated with persister formation and virulence factors. The functions of two PhoU homologs, PhoU1 and PhoU2, in S. aureus are unclear yet. In this study, single- and double-deletion mutants of phoU1 and phoU2 were generated in strain USA500 2395. The ΔphoU1 or ΔphoU2 mutants displayed a change in persister formation and virulence compared to the parent strain; the persisters to vancomycin and levofloxacin were decreased at least 1,000-fold, and the number of intracellular bacteria surviving in the A549 cells for 24 h decreased to 82 or 85%. The α-hemolysin expression and activity were increased in the ΔphoU2 mutants. Transcriptome analysis revealed that 573 or 285 genes were differentially expressed by at least 2.0-fold in the ΔphoU1 or ΔphoU2 mutant vs. the wild type. Genes involved in carbon and pyruvate metabolism were up-regulated, and virulence genes and virulence regulatory genes were down-regulated, including type VII secretion system, serine protease, leukocidin, global regulator (sarA, rot), and the two-component signal transduction system (saeS). Correspondingly, the deletion of the phoU1 or phoU2 resulted in increased levels of intracellular pyruvate and ATP. Deletion of the phoU2, but not the phoU1, resulted in the up-regulation of inorganic phosphate transport genes and increased levels of intracellular inorganic polyphosphate. In conclusion, both PhoU1 and PhoU2 in S. aureus regulate virulence by the down-regulation of multiple virulence factors (type VII secretion system, serine protease, and leucocidin) and the persister generation by hyperactive carbon metabolism accompanied by increasing intracellular ATP. The results in S. aureus are different from what we have previously found in Staphylococcus epidermis, where only PhoU2 regulates biofilm and persister formation. The different functions of PhoU homologs between the two species of Staphylococcus warrant further investigation.
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Affiliation(s)
- Yongpeng Shang
- Key Laboratory of Medical Molecular Virology of MOE and MOH, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Xiaofei Wang
- Key Laboratory of Medical Molecular Virology of MOE and MOH, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Zhong Chen
- Key Laboratory of Medical Molecular Virology of MOE and MOH, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Zhihui Lyu
- Key Laboratory of Medical Molecular Virology of MOE and MOH, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Zhiwei Lin
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Union Shenzhen Hospital, Huazhong University of Science and Technology, Shenzhen, China
| | - Jinxin Zheng
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Union Shenzhen Hospital, Huazhong University of Science and Technology, Shenzhen, China
| | - Yang Wu
- Key Laboratory of Medical Molecular Virology of MOE and MOH, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Qiwen Deng
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Union Shenzhen Hospital, Huazhong University of Science and Technology, Shenzhen, China
| | - Zhijian Yu
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Union Shenzhen Hospital, Huazhong University of Science and Technology, Shenzhen, China
| | - Ying Zhang
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States
| | - Di Qu
- Key Laboratory of Medical Molecular Virology of MOE and MOH, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, China
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Disruption of Phosphate Homeostasis Sensitizes Staphylococcus aureus to Nutritional Immunity. Infect Immun 2020; 88:IAI.00102-20. [PMID: 32205403 DOI: 10.1128/iai.00102-20] [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: 02/20/2020] [Accepted: 03/16/2020] [Indexed: 12/12/2022] Open
Abstract
To control infection, mammals actively withhold essential nutrients, including the transition metal manganese, by a process termed nutritional immunity. A critical component of this host response is the manganese-chelating protein calprotectin. While many bacterial mechanisms for overcoming nutritional immunity have been identified, the intersection between metal starvation and other essential inorganic nutrients has not been investigated. Here, we report that overexpression of an operon encoding a highly conserved inorganic phosphate importer, PstSCAB, increases the sensitivity of Staphylococcus aureus to calprotectin-mediated manganese sequestration. Further analysis revealed that overexpression of pstSCAB does not disrupt manganese acquisition or result in overaccumulation of phosphate by S. aureus However, it does reduce the ability of S. aureus to grow in phosphate-replete defined medium. Overexpression of pstSCAB does not aberrantly activate the phosphate-responsive two-component system PhoPR, nor was this two-component system required for sensitivity to manganese starvation. In a mouse model of systemic staphylococcal disease, a pstSCAB-overexpressing strain is significantly attenuated compared to wild-type S. aureus This defect is partially reversed in a calprotectin-deficient mouse, in which manganese is more readily available. Given that expression of pstSCAB is regulated by PhoPR, these findings suggest that overactivation of PhoPR would diminish the ability of S. aureus to resist nutritional immunity and cause infection. As PhoPR is also necessary for bacterial virulence, these findings imply that phosphate homeostasis represents a critical regulatory node whose activity must be precisely controlled in order for S. aureus and other pathogens to cause infection.
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Liu X, Wang C, Yan B, Lyu L, Takiff HE, Gao Q. The potassium transporter KdpA affects persister formation by regulating ATP levels in Mycobacterium marinum. Emerg Microbes Infect 2020; 9:129-139. [PMID: 31913766 PMCID: PMC6968386 DOI: 10.1080/22221751.2019.1710090] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Mycobacterial persistence mechanisms remain to be fully characterized. Screening a transposon insertion library of Mycobacterium marinum identified kdpA, whose inactivation reduced the fraction of persisters after exposure to rifampicin. kdpA encodes a transmembrane protein that is part of the Kdp-ATPase, an ATP-dependent high-affinity potassium (K+) transport system. We found that kdpA is induced under low K+ conditions and is required for pH homeostasis and growth in media with low concentrations of K+. The inactivation of the Kdp system in a kdpA insertion mutant caused hyperpolarization of the cross-membrane potential, increased proton motive force (PMF) and elevated levels of intracellular ATP. The KdpA mutant phenotype could be complemented with a functional kdpA gene or supplementation with high K+ concentrations. Taken together, our results suggest that the Kdp system is required for ATP homeostasis and persister formation. The results also confirm that ATP-mediated regulation of persister formation is a general mechanism in bacteria, and suggest that K+ transporters could play a role in the regulation of ATP levels and persistence. These findings could have implications for the development of new drugs that could either target persisters or reduce their presence.
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Affiliation(s)
- Xiaofan Liu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College and Shanghai Public Health Clinical Center, Fudan University, Shanghai, People's Republic of China
| | - Chuan Wang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College and Shanghai Public Health Clinical Center, Fudan University, Shanghai, People's Republic of China
| | - Bo Yan
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, People's Republic of China
| | - Liangdong Lyu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College and Shanghai Public Health Clinical Center, Fudan University, Shanghai, People's Republic of China
| | - Howard E Takiff
- Integrated Mycobacterial Pathogenomics Unit, Institut Pasteur, Paris, France
| | - Qian Gao
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College and Shanghai Public Health Clinical Center, Fudan University, Shanghai, People's Republic of China
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Behera S, Pattnaik S. Persister cell development among Enterobacteriaceae, Pseudomonadaceae, Mycobacteriaceae and Staphylococcaceae biotypes: A review. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2019. [DOI: 10.1016/j.bcab.2019.101401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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Khlebodarova TM, Likhoshvai VA. Molecular Mechanisms of Non-Inherited Antibiotic Tolerance in Bacteria and Archaea. Mol Biol 2019. [DOI: 10.1134/s0026893319040058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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16
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The Salmonella virulence protein MgtC promotes phosphate uptake inside macrophages. Nat Commun 2019; 10:3326. [PMID: 31346161 PMCID: PMC6658541 DOI: 10.1038/s41467-019-11318-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 07/05/2019] [Indexed: 02/06/2023] Open
Abstract
The MgtC virulence protein from the intracellular pathogen Salmonella enterica is required for its intramacrophage survival and virulence in mice and this requirement of MgtC is conserved in several intracellular pathogens including Mycobacterium tuberculosis. Despite its critical role in survival within macrophages, only a few molecular targets of the MgtC protein have been identified. Here, we report that MgtC targets PhoR histidine kinase and activates phosphate transport independently of the available phosphate concentration. A single amino acid substitution in PhoR prevents its binding to MgtC, thus abrogating MgtC-mediated phosphate transport. Surprisingly, the removal of MgtC’s effect on the ability to transport phosphate renders Salmonella hypervirulent and decreases a non-replicating population inside macrophages, indicating that MgtC-mediated phosphate transport is required for normal Salmonella pathogenesis. This provides an example of a virulence protein directly activating a pathogen’s phosphate transport inside host. The virulence factor MgtC is essential for intracellular macrophage survival of Salmonella enterica. Here, the authors show that MgtC targets the PhoB/PhoR regulatory system leading to phosphate uptake inside macrophages and that both phoR mutation and phoB deletion renders Salmonella hypervirulent in mice.
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Mycobacterium bovis BCG Surface Antigens Expressed under the Granuloma-Like Conditions as Potential Inducers of the Protective Immunity. Int J Microbiol 2019; 2019:9167271. [PMID: 31281365 PMCID: PMC6589241 DOI: 10.1155/2019/9167271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 04/11/2019] [Accepted: 04/24/2019] [Indexed: 01/27/2023] Open
Abstract
Bovine tuberculosis (bTB) is a highly transmissible infection and remains of great concern as a zoonosis. The worldwide incidence of bTB is in rise, creating potential reservoir and increased infection risk for humans and animals. In attempts to identify novel surface antigens of Mycobacterium bovis as a proof-of-concept for potential inducers of protective immunity, we investigated surface proteome of M. bovis BCG strain that was cultured under the granuloma-like condition. We also demonstrated that the pathogen exposed to the biologically relevant environment has greater binding and invasion abilities to host cells than those of bacteria incubated under regular laboratory conditions. A total of 957 surface-exposed proteins were identified for BCG cultured under laboratory condition, whereas 1,097 proteins were expressed under the granuloma-like condition. The overexpression of Mb1524, Mb01_03198, Mb1595_p3681 (PhoU1 same as phoY1_1), and Mb1595_p0530 (HbhA) surface proteins in Mycobacterium smegmatis leads to increased binding and invasion to mucosal cells. We also examined the immunogenicity of purified recombinant proteins and tested M. smegmatis overexpressing these surface antigens for the induction of protective immunity in mice. Significantly high levels of specific IgA and IgG antibodies were observed in recombinant protein immunized groups by both inhalation and intraperitoneal (IP) routes, but only IP delivery induced high total IgA and IgG levels. We did not detect major differences in antibody levels in the M. smegmatis group that overexpressed surface antigens. In addition, the bacterial load was significantly reduced in the lungs of mice immunized with the combination of inhaled recombinant proteins. Our findings suggest that the activation of the mucosal immunity can lead to increased ability to confer protection upon M. bovis BCG infection.
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Mandal S, Njikan S, Kumar A, Early JV, Parish T. The relevance of persisters in tuberculosis drug discovery. MICROBIOLOGY-SGM 2019; 165:492-499. [PMID: 30775961 DOI: 10.1099/mic.0.000760] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Bacterial persisters are a subpopulation of cells that exhibit phenotypic resistance during exposure to a lethal dose of antibiotics. They are difficult to target and thought to contribute to the long treatment duration required for tuberculosis. Understanding the molecular and cellular biology of persisters is critical to finding new tuberculosis drugs that shorten treatment. This review focuses on mycobacterial persisters and describes the challenges they pose in tuberculosis therapy, their characteristics and formation, how persistence leads to resistance, and the current approaches being used to target persisters within mycobacterial drug discovery.
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Affiliation(s)
- Soma Mandal
- TB Discovery Research, Infectious Disease Research Institute, 1616 Eastlake Ave. E, Suite 400, Seattle, WA 98102, USA
| | - Samuel Njikan
- TB Discovery Research, Infectious Disease Research Institute, 1616 Eastlake Ave. E, Suite 400, Seattle, WA 98102, USA
| | - Anuradha Kumar
- TB Discovery Research, Infectious Disease Research Institute, 1616 Eastlake Ave. E, Suite 400, Seattle, WA 98102, USA
| | - Julie V Early
- TB Discovery Research, Infectious Disease Research Institute, 1616 Eastlake Ave. E, Suite 400, Seattle, WA 98102, USA
| | - Tanya Parish
- TB Discovery Research, Infectious Disease Research Institute, 1616 Eastlake Ave. E, Suite 400, Seattle, WA 98102, USA
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Mechanisms of Bacterial Tolerance and Persistence in the Gastrointestinal and Respiratory Environments. Clin Microbiol Rev 2018; 31:31/4/e00023-18. [PMID: 30068737 DOI: 10.1128/cmr.00023-18] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Pathogens that infect the gastrointestinal and respiratory tracts are subjected to intense pressure due to the environmental conditions of the surroundings. This pressure has led to the development of mechanisms of bacterial tolerance or persistence which enable microorganisms to survive in these locations. In this review, we analyze the general stress response (RpoS mediated), reactive oxygen species (ROS) tolerance, energy metabolism, drug efflux pumps, SOS response, quorum sensing (QS) bacterial communication, (p)ppGpp signaling, and toxin-antitoxin (TA) systems of pathogens, such as Escherichia coli, Salmonella spp., Vibrio spp., Helicobacter spp., Campylobacter jejuni, Enterococcus spp., Shigella spp., Yersinia spp., and Clostridium difficile, all of which inhabit the gastrointestinal tract. The following respiratory tract pathogens are also considered: Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Burkholderia cenocepacia, and Mycobacterium tuberculosis Knowledge of the molecular mechanisms regulating the bacterial tolerance and persistence phenotypes is essential in the fight against multiresistant pathogens, as it will enable the identification of new targets for developing innovative anti-infective treatments.
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20
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Ma J, Tian M, Fan X, Yu Q, Jing Y, Wang W, Li L, Zhou Z. Mycobacterium tuberculosis multistage antigens confer comprehensive protection against pre- and post-exposure infections by driving Th1-type T cell immunity. Oncotarget 2018; 7:63804-63815. [PMID: 27566581 PMCID: PMC5325405 DOI: 10.18632/oncotarget.11542] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Accepted: 08/11/2016] [Indexed: 12/29/2022] Open
Abstract
There is an urgent need for a vaccine against tuberculosis (TB) that is more effective than the current sole licensed option. However, target antigens of Mycobacterium tuberculosis with the vaccine potential remain elusive. Five immunodominant antigens with characteristic expressions at the stages of primary infection (Ag85A), the regulation of nutrition and metabolism when transferring from rapid growth to latency (PhoY2 and Rv3407), latency (Rv2626c), and reactivation (RpfB) were selected to construct the fusion polyprotein WH121, which has better immunogenicity and protection than each multistage antigen. DMT adjuvanted WH121 vaccinated C57BL/6 mice could confer persistent and significant protection against the respiratory challenge with 80 CFU of virulent M. tuberculosis H37Rv at 9 and 18 weeks after immunization, as the BCG vaccine did. Moreover, WH121/DMT could boost the BCG primed mice against post-exposure infection, and more significantly inhibit the growth of M. tuberculosis in the spleen than BCG repeat vaccination. The protection elicited by WH121/DMT is attributed to the WH121-specific Th1-type biased immune responses, characterized by increased antigen-specific IgG2a/IgG1 ratio and high levels of IFN-γ secreted by the splenocytes of vaccinated mice. In particular, high levels of IFN-γ+ TEM cells in the spleen are an effective biomarker for the vaccine-induced early protection, and the persistent protection mainly depends on the increasing IL-2+IFN-γ+CD4+ and CD8+ T cells, especially IL-2+ TCM cells. These findings demonstrate that multistage-specific antigens might be promising targets for the next generation TB vaccine, and a combination of these antigens such as WH121/DMT is required for further preclinical evaluation.
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Affiliation(s)
- Jilei Ma
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Maopeng Tian
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Xionglin Fan
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Qi Yu
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Yukai Jing
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
| | - Weihua Wang
- Wuhan Pulmonary Hospital, Wuhan Institute for Tuberculosis Control, Wuhan 430030, People's Republic of China
| | - Li Li
- Wuhan Pulmonary Hospital, Wuhan Institute for Tuberculosis Control, Wuhan 430030, People's Republic of China
| | - Zijie Zhou
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
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Brokaw AM, Eide BJ, Muradian M, Boster JM, Tischler AD. Mycobacterium smegmatis PhoU Proteins Have Overlapping Functions in Phosphate Signaling and Are Essential. Front Microbiol 2017; 8:2523. [PMID: 29326670 PMCID: PMC5741670 DOI: 10.3389/fmicb.2017.02523] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 12/05/2017] [Indexed: 11/13/2022] Open
Abstract
Many bacteria regulate gene expression in response to phosphate availability using a two-component signal transduction system, the activity of which is controlled by interaction with the Pst phosphate specific transporter and a cytoplasmic protein PhoU. Mycobacterium tuberculosis, the causative agent of tuberculosis, requires its phosphate sensing signal transduction system for virulence and antibiotic tolerance, but the molecular mechanisms of phosphate sensing remain poorly characterized. M. smegmatis serves as a model for studying mycobacterial pathogens including M. tuberculosis. M. smegmatis encodes two proteins with similarity to PhoU, but it was unknown if both proteins participated in signal transduction with the phosphate-responsive SenX3-RegX3 two-component system. We constructed phoU single and double deletion mutants and tested expression of genes in the RegX3 regulon. Only the ΔphoU1ΔphoU2 mutant exhibited constitutive activation of all the RegX3-regulated genes examined, suggesting that M. smegmatis PhoU1 and PhoU2 have overlapping functions in inhibiting activity of the SenX3-RegX3 two-component system when phosphate is readily available. The ΔphoU1ΔphoU2 mutant also exhibited decreased tolerance to several anti-tubercular drugs. However, a complex plasmid swapping strategy was required to generate the ΔphoU1ΔphoU2 mutant, suggesting that either phoU1 or phoU2 is essential for in vitro growth of M. smegmatis. Using whole-genome sequencing, we demonstrated that all five of the ΔphoU1ΔphoU2 mutants we isolated had independent suppressor mutations predicted to disrupt the function of the Pst phosphate transporter, suggesting that in the absence of the PhoU proteins phosphate uptake by the Pst system is toxic. Collectively, our data demonstrate that the two M. smegmatis PhoU orthologs have overlapping functions in both controlling SenX3-RegX3 activity in response to phosphate availability and regulating phosphate transport by the Pst system. Our results suggest that M. smegmatis can serve as a tractable model for further characterization of the molecular mechanism of phosphate sensing in mycobacteria and to screen for compounds that would interfere with signal transduction and thereby increase the efficacy of existing anti-tubercular antibiotics.
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Affiliation(s)
- Alyssa M Brokaw
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, United States
| | - Benjamin J Eide
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, United States
| | - Michael Muradian
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, United States
| | - Joshua M Boster
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, United States
| | - Anna D Tischler
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, United States
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PhoU2 but Not PhoU1 as an Important Regulator of Biofilm Formation and Tolerance to Multiple Stresses by Participating in Various Fundamental Metabolic Processes in Staphylococcus epidermidis. J Bacteriol 2017; 199:JB.00219-17. [PMID: 28947672 PMCID: PMC5686610 DOI: 10.1128/jb.00219-17] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 08/18/2017] [Indexed: 12/17/2022] Open
Abstract
PhoU, a conserved protein that has been proposed to coordinate phosphate import, is a negative regulator of drug tolerance in most bacteria. In Staphylococcus epidermidis, the role of PhoU in biofilm formation and drug tolerance has not yet been investigated. Two PhoU homologs in the genome of S. epidermidis have been identified by the presence of the conserved motif E(D)XXXD of PhoU. We separately constructed ΔphoU1 and ΔphoU2 mutants of S. epidermidis strain 1457. The ΔphoU2 mutant displayed growth retardation, a weakened biofilm formation capacity, a higher sensitivity to H2O2, and reduced tolerance to multiple antibiotics. However, deletion of phoU1 had no effect on those. We compared the transcriptome profiles of the ΔphoU2 and ΔphoU1 mutants with that of the parent strain. In the ΔphoU2 mutant, expression of genes related to inorganic phosphate uptake was significantly upregulated (pst operon) and the levels of intracellular inorganic polyphosphate (polyP) were increased. In the ΔphoU2 mutant, expression of enzymes in the pentose phosphate pathway (PPP) was downregulated and less NADP (NADPH) was detected, consistent with the high sensitivity to H2O2 and the growth retardation of the ΔphoU2 mutant. The upregulated expression of ATP synthase was consistent with the high intracellular ATP content in the ΔphoU2 mutant, which may have been related to the lower drug tolerance of the ΔphoU2 mutant. This study demonstrates that PhoU2, but not PhoU1, in S. epidermidis regulates bacterial growth, biofilm formation, oxidative stress, and drug tolerance in association with alterations to inorganic phosphate metabolism, the pentose phosphate pathway, galactose metabolism, the tricarboxylic acid (TCA) or citric cycle, glycolysis and gluconeogenesis, and respiratory reactions. IMPORTANCE PhoU is widely conserved throughout the bacterial kingdom and plays an important role in response to stress and metabolic maintenance. In our study, two PhoU homologs were found in S. epidermidis. The function of phoU2, but not phoU1, in S. epidermidis is related to growth, drug tolerance, the oxidative stress response, polyP levels, and ATP accumulation. In addition, phoU2 regulates biofilm formation. Hence, phoU2 is a regulator of both drug tolerance and biofilm formation, which are two bacterial properties that present major challenges to the clinical treatment of infections. Analysis of differential gene expression revealed that phoU2 is involved in fundamental metabolic processes, such as the PPP pathway. These findings indicate that phoU2 is a crucial regulator in S. epidermidis.
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Padelli M, Leven C, Sakka M, Plée-Gautier E, Carré JL. [Causes, consequences and treatment of hypophosphatemia: A systematic review]. Presse Med 2017; 46:987-999. [PMID: 29089216 DOI: 10.1016/j.lpm.2017.09.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 08/24/2017] [Accepted: 09/12/2017] [Indexed: 12/16/2022] Open
Abstract
CONTEXT Although hypophosphatemia is usually very seldom, it can reach two to 3% of hospitalized patients and until 28% of intensive care unit patients. Due to the lack of knowledge, clinical practice regarding seeking or treatment of hypophosphatemia is very heterogenous. However its clinical consequences might be heavy. A better knowledge of its causes, physiopathological effects and treatment should lead to a documented and homogenous care of these patients in clinics. OBJECTIVE The aim of our study was a systematic review of littérature, seeking for publications about causes, consequences and treatment of hypophosphatemia. DOCUMENTARY SOURCES (KEYWORDS AND LANGUAGE) A research has been conducted on the Medline database by using the following keywords "phosphorus supplementation", "hypophosphatemia" and ("physiopathology" or "complications"). RESULTS Three mains mechanisms might be responsible for hypophosphatemia: a decrease in digestive absorption, a rise in kidney excretion and a transfer of phosphorus to the intracellular compartment. Denutrition, acid base balance troubles, parenteral nutrition or several drugs are capable of provoking or favouring hypophosphatemia. All these situations are frequently encountered in intensive care unit. Consequences of hypophosphatemia might be serious. Best studied and documented are cardiac and respiratory muscle contractility decrease, sometimes leading to acute cardiac and respiratory failure, cardiac rhythm troubles and cardiac arrest. Hypophosphatemia is frequent during sepsis. It could be responsible for leucocyte dysfunction that might favour or increase sepsis. The treatment of hypophosphatemia is usually simple through a supplementation that quickly restores a regular concentration, with few adverse effects when regularly used. CONCLUSION During at-risk situations, the systematic search for hypophosphatemia and its treatment may limit the occurrence of serious consequences.
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Affiliation(s)
- Maël Padelli
- University hospital of Brest, department of biochemistry and pharmaco-toxicology, 29200 Brest, France.
| | - Cyril Leven
- University hospital of Brest, department of biochemistry and pharmaco-toxicology, 29200 Brest, France
| | - Mehdi Sakka
- University hospital of Brest, department of biochemistry and pharmaco-toxicology, 29200 Brest, France
| | - Emmanuelle Plée-Gautier
- University hospital of Brest, department of biochemistry and pharmaco-toxicology, 29200 Brest, France
| | - Jean-Luc Carré
- University hospital of Brest, department of biochemistry and pharmaco-toxicology, 29200 Brest, France
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Mycobacterium tuberculosis PhoY Proteins Promote Persister Formation by Mediating Pst/SenX3-RegX3 Phosphate Sensing. mBio 2017; 8:mBio.00494-17. [PMID: 28698272 PMCID: PMC5513712 DOI: 10.1128/mbio.00494-17] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The Mycobacterium tuberculosis phosphate-specific transport (Pst) system controls gene expression in response to phosphate availability by inhibiting the activation of the SenX3-RegX3 two-component system under phosphate-rich conditions, but the mechanism of communication between these systems is unknown. In Escherichia coli, inhibition of the two-component system PhoR-PhoB under phosphate-rich conditions requires both the Pst system and PhoU, a putative adaptor protein. E. coli PhoU is also involved in the formation of persisters, a subpopulation of phenotypically antibiotic-tolerant bacteria. M. tuberculosis encodes two PhoU orthologs, PhoY1 and PhoY2. We generated phoY single- and double-deletion mutants and examined the expression of RegX3-regulated genes by quantitative reverse transcription-PCR (qRT-PCR). Gene expression was increased only in the ΔphoY1 ΔphoY2 double mutant and could be restored to the wild-type level by complementation with either phoY1 or phoY2 or by deletion of regX3 These data suggest that the PhoY proteins function redundantly to inhibit SenX3-RegX3 activation. We analyzed the frequencies of antibiotic-tolerant persister variants in the phoY mutants using several antibiotic combinations. Persister frequency was decreased at least 40-fold in the ΔphoY1 ΔphoY2 mutant compared to the frequency in the wild type, and this phenotype was RegX3 dependent. A ΔpstA1 mutant lacking a Pst system transmembrane component exhibited a similar RegX3-dependent decrease in persister frequency. In aerosol-infected mice, the ΔphoY1 ΔphoY2 and ΔpstA1 mutants were more susceptible to treatment with rifampin but not isoniazid. Our data demonstrate that disrupting phosphate sensing mediated by the PhoY proteins and the Pst system enhances the susceptibility of M. tuberculosis to antibiotics both in vitro and during infection.IMPORTANCE Persister variants, subpopulations of bacteria that are phenotypically antibiotic tolerant, contribute to the lengthy treatment times required to cure Mycobacterium tuberculosis infection, but the molecular mechanisms governing their formation and maintenance are poorly characterized. Here, we demonstrate that a phosphate-sensing signal transduction system, comprising the Pst phosphate transporter, the two-component system SenX3-RegX3, and functionally redundant PhoY proteins that mediate signaling between Pst and SenX3-RegX3, influences persister formation. Activation of RegX3 by deletion of the phoY genes or a Pst system component resulted in decreased persister formation in vitro Activated RegX3 also limited persister formation during growth under phosphate-limiting conditions. Importantly, increased susceptibility to the front-line drug rifampin was also observed in a mouse infection model. Thus, the M. tuberculosis phosphate-sensing signal transduction system contributes to antibiotic tolerance and is a potential target for the development of novel therapeutics that may shorten the duration of tuberculosis treatment.
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25
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Van den Bergh B, Fauvart M, Michiels J. Formation, physiology, ecology, evolution and clinical importance of bacterial persisters. FEMS Microbiol Rev 2017; 41:219-251. [DOI: 10.1093/femsre/fux001] [Citation(s) in RCA: 217] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 01/12/2017] [Indexed: 12/19/2022] Open
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Santos-Beneit F, Ordóñez-Robles M, Martín JF. Glycopeptide resistance: Links with inorganic phosphate metabolism and cell envelope stress. Biochem Pharmacol 2016; 133:74-85. [PMID: 27894856 DOI: 10.1016/j.bcp.2016.11.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 11/15/2016] [Indexed: 10/20/2022]
Abstract
Antimicrobial resistance is a critical health issue today. Many pathogens have become resistant to many or all available antibiotics and limited new antibiotics are in the pipeline. Glycopeptides are used as a 'last resort' antibiotic treatment for many bacterial infections, but worryingly, glycopeptide resistance has spread to very important pathogens such as Enterococcus faecium and Staphylococcus aureus. Bacteria confront multiple stresses in their natural environments, including nutritional starvation and the action of cell-wall stressing agents. These stresses impact bacterial susceptibility to different antimicrobials. This article aims to review the links between glycopeptide resistance and different stresses, especially those related with cell-wall biosynthesis and inorganic phosphate metabolism, and to discuss promising alternatives to classical antibiotics to avoid the problem of antimicrobial resistance.
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Affiliation(s)
- Fernando Santos-Beneit
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, NE2 4AX Newcastle upon Tyne, UK
| | - María Ordóñez-Robles
- Department of Biotechnology, Faculty of Natural Sciences and Technology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Juan F Martín
- Microbiology Area, Department of Molecular Biology, University of León, 24071 León, Spain.
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Zheng JJ, Sinha D, Wayne KJ, Winkler ME. Physiological Roles of the Dual Phosphate Transporter Systems in Low and High Phosphate Conditions and in Capsule Maintenance of Streptococcus pneumoniae D39. Front Cell Infect Microbiol 2016; 6:63. [PMID: 27379215 PMCID: PMC4913102 DOI: 10.3389/fcimb.2016.00063] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 05/27/2016] [Indexed: 12/28/2022] Open
Abstract
Unlike most bacteria, Streptococcus pneumoniae (pneumococcus) has two evolutionarily distinct ABC transporters (Pst1 and Pst2) for inorganic phosphate (Pi) uptake. The genes encoding a two-component regulator (PnpRS) are located immediately upstream of the pst1 operon. Both the pst1 and pst2 operons encode putative PhoU-family regulators (PhoU1 and PhoU2) at their ends. This study addresses why S. pneumoniae contains dual Pi uptake systems and the regulation and contribution of the Pst1 and Pst2 systems in conditions of high (mM) Pi amount and low (μM) Pi amount. We show that in unencapsulated mutants, both pst1 and pst2 can be deleted, and Pi is taken up by a third Na+/Pi co-transporter, designated as NptA. In contrast, either pst1 or pst2 is unexpectedly required for the growth of capsule producing strains. We used a combination of mutational analysis, transcript level determinations by qRT-PCR and RNA-Seq, assays for cellular PnpR~P amounts by SDS-PAGE, and pulse-Pi uptake experiments to study the regulation of Pi uptake. In high Pi medium, PhoU2 serves as the master negative regulator of Pst2 transporter function and PnpR~P levels (post-transcriptionally). ΔphoU2 mutants have high PnpR~P levels and induction of the pst1 operon, poor growth, and sensitivity to antibiotics, possibly due to high Pi accumulation. In low Pi medium, Pst2 is still active, but PnpR~P amount and pst1 operon levels increase. Together, these results support a model in which pneumococcus maintains high Pi transport in high and low Pi conditions that is required for optimal capsule biosynthesis.
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Affiliation(s)
- Jiaqi J Zheng
- Department of Biology, Indiana University Bloomington Bloomington, IN, USA
| | - Dhriti Sinha
- Department of Biology, Indiana University Bloomington Bloomington, IN, USA
| | - Kyle J Wayne
- Department of Biology, Indiana University Bloomington Bloomington, IN, USA
| | - Malcolm E Winkler
- Department of Biology, Indiana University Bloomington Bloomington, IN, USA
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28
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Nguyen L. Antibiotic resistance mechanisms in M. tuberculosis: an update. Arch Toxicol 2016; 90:1585-604. [PMID: 27161440 DOI: 10.1007/s00204-016-1727-6] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 04/27/2016] [Indexed: 12/16/2022]
Abstract
Treatment of tuberculosis (TB) has been a therapeutic challenge because of not only the naturally high resistance level of Mycobacterium tuberculosis to antibiotics but also the newly acquired mutations that confer further resistance. Currently standardized regimens require patients to daily ingest up to four drugs under direct observation of a healthcare worker for a period of 6-9 months. Although they are quite effective in treating drug susceptible TB, these lengthy treatments often lead to patient non-adherence, which catalyzes for the emergence of M. tuberculosis strains that are increasingly resistant to the few available anti-TB drugs. The rapid evolution of M. tuberculosis, from mono-drug-resistant to multiple drug-resistant, extensively drug-resistant and most recently totally drug-resistant strains, is threatening to make TB once again an untreatable disease if new therapeutic options do not soon become available. Here, I discuss the molecular mechanisms by which M. tuberculosis confers its profound resistance to antibiotics. This knowledge may help in developing novel strategies for weakening drug resistance, thus enhancing the potency of available antibiotics against both drug susceptible and resistant M. tuberculosis strains.
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Affiliation(s)
- Liem Nguyen
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
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29
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Duan X, Li Y, Du Q, Huang Q, Guo S, Xu M, Lin Y, Liu Z, Xie J. Mycobacterium Lysine ε-aminotransferase is a novel alarmone metabolism related persister gene via dysregulating the intracellular amino acid level. Sci Rep 2016; 6:19695. [PMID: 26806099 PMCID: PMC4726150 DOI: 10.1038/srep19695] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 12/16/2015] [Indexed: 01/07/2023] Open
Abstract
Bacterial persisters, usually slow-growing, non-replicating cells highly tolerant to antibiotics, play a crucial role contributing to the recalcitrance of chronic infections and treatment failure. Understanding the molecular mechanism of persister cells formation and maintenance would obviously inspire the discovery of new antibiotics. The significant upregulation of Mycobacterium tuberculosis Rv3290c, a highly conserved mycobacterial lysine ε-aminotransferase (LAT) during hypoxia persistent model, suggested a role of LAT in persistence. To test this, a lat deleted Mycobacterium smegmatis was constructed. The expression of transcriptional regulator leucine-responsive regulatory protein (LrpA) and the amino acids abundance in M. smegmatis lat deletion mutants were lowered. Thus, the persistence capacity of the deletion mutant was impaired upon norfloxacin exposure under nutrient starvation. In summary, our study firstly reported the involvement of mycobacterium LAT in persister formation, and possibly through altering the intracellular amino acid metabolism balance.
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Affiliation(s)
- Xiangke Duan
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, key laboratory of Eco-environment three gorges reservoir, Ministry of Education, School of Life Sciences, Southwest University. Chongqing 400715, China
| | - Yunsong Li
- Department of thoracic surgery, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing Chest Hospital, Capital Medical University, Beijing 101149, China
| | - Qinglin Du
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, key laboratory of Eco-environment three gorges reservoir, Ministry of Education, School of Life Sciences, Southwest University. Chongqing 400715, China
| | - Qinqin Huang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, key laboratory of Eco-environment three gorges reservoir, Ministry of Education, School of Life Sciences, Southwest University. Chongqing 400715, China
| | - Siyao Guo
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, key laboratory of Eco-environment three gorges reservoir, Ministry of Education, School of Life Sciences, Southwest University. Chongqing 400715, China.,Hanhong College, Southwest University. Chongqing 400715, China
| | - Mengmeng Xu
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, key laboratory of Eco-environment three gorges reservoir, Ministry of Education, School of Life Sciences, Southwest University. Chongqing 400715, China
| | - Yanping Lin
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, key laboratory of Eco-environment three gorges reservoir, Ministry of Education, School of Life Sciences, Southwest University. Chongqing 400715, China
| | - Zhidong Liu
- Department of thoracic surgery, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing Chest Hospital, Capital Medical University, Beijing 101149, China
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, key laboratory of Eco-environment three gorges reservoir, Ministry of Education, School of Life Sciences, Southwest University. Chongqing 400715, China
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Santos-Beneit F. The Pho regulon: a huge regulatory network in bacteria. Front Microbiol 2015; 6:402. [PMID: 25983732 PMCID: PMC4415409 DOI: 10.3389/fmicb.2015.00402] [Citation(s) in RCA: 214] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 04/17/2015] [Indexed: 12/15/2022] Open
Abstract
One of the most important achievements of bacteria is its capability to adapt to the changing conditions of the environment. The competition for nutrients with other microorganisms, especially in the soil, where nutritional conditions are more variable, has led bacteria to evolve a plethora of mechanisms to rapidly fine-tune the requirements of the cell. One of the essential nutrients that are normally found in low concentrations in nature is inorganic phosphate (Pi). Bacteria, as well as other organisms, have developed several systems to cope for the scarcity of this nutrient. To date, the unique mechanism responding to Pi starvation known in detail is the Pho regulon, which is normally controlled by a two component system and constitutes one of the most sensible and efficient regulatory mechanisms in bacteria. Many new members of the Pho regulon have emerged in the last years in several bacteria; however, there are still many unknown questions regarding the activation and function of the whole system. This review describes the most important findings of the last three decades in relation to Pi regulation in bacteria, including: the PHO box, the Pi signaling pathway and the Pi starvation response. The role of the Pho regulon in nutritional regulation cross-talk, secondary metabolite production, and pathogenesis is discussed in detail.
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Affiliation(s)
- Fernando Santos-Beneit
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne UK
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Latent tuberculosis infection: myths, models, and molecular mechanisms. Microbiol Mol Biol Rev 2015; 78:343-71. [PMID: 25184558 DOI: 10.1128/mmbr.00010-14] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The aim of this review is to present the current state of knowledge on human latent tuberculosis infection (LTBI) based on clinical studies and observations, as well as experimental in vitro and animal models. Several key terms are defined, including "latency," "persistence," "dormancy," and "antibiotic tolerance." Dogmas prevalent in the field are critically examined based on available clinical and experimental data, including the long-held beliefs that infection is either latent or active, that LTBI represents a small population of nonreplicating, "dormant" bacilli, and that caseous granulomas are the haven for LTBI. The role of host factors, such as CD4(+) and CD8(+) T cells, T regulatory cells, tumor necrosis factor alpha (TNF-α), and gamma interferon (IFN-γ), in controlling TB infection is discussed. We also highlight microbial regulatory and metabolic pathways implicated in bacillary growth restriction and antibiotic tolerance under various physiologically relevant conditions. Finally, we pose several clinically important questions, which remain unanswered and will serve to stimulate future research on LTBI.
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Stehr M, Elamin AA, Singh M. Pyrazinamide: the importance of uncovering the mechanisms of action in mycobacteria. Expert Rev Anti Infect Ther 2015; 13:593-603. [PMID: 25746054 DOI: 10.1586/14787210.2015.1021784] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Pyrazinamide (PZA) is still one of the key drugs used in current therapeutic regimens for tuberculosis (TB). Despite its importance for TB therapy, the mode of action of PZA remains unknown. PZA has to be converted to its active form pyrazinoic acid (POA) by the nicotinamidase PncA and is then excreted by an unknown efflux pump. At acidic conditions, POA is protonated to HPOA and is reabsorbed into the cell where it causes cellular damage. For a long time, it has been thought that PZA/POA has no defined target of action, but recent studies have shown that both PZA and POA have several different targets interfering with diverse biochemical pathways, especially in the NAD(+) and energy metabolism. PZA resistance seems to depend not only on a defective pyrazinamidase but is also rather a result of the interplay of many different enzyme targets and transport mechanisms.
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Affiliation(s)
- Matthias Stehr
- LIONEX Diagnostics and Therapeutics GmbH, Salzdahlumer Straße 196, D-38126, Braunschweig, Germany
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phoU inactivation in Pseudomonas aeruginosa enhances accumulation of ppGpp and polyphosphate. Appl Environ Microbiol 2015; 81:3006-15. [PMID: 25710363 DOI: 10.1128/aem.04168-14] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 02/13/2015] [Indexed: 12/28/2022] Open
Abstract
Inorganic polyphosphate (polyP) is a linear polymer composed of several molecules of orthophosphate (Pi) linked by energy-rich phosphoanhydride bonds. In Pseudomonas aeruginosa, Pi is taken up by the ABC transporter Pst, encoded by an operon consisting of five genes. The first four genes encode proteins involved in the transport of Pi and the last gene of the operon, phoU, codes for a protein which exact function is unknown. We show here that the inactivation of phoU in P. aeruginosa enhanced Pi removal from the medium and polyP accumulation. The phoU mutant also accumulated high levels of the alarmone guanosine tetraphosphate (ppGpp), which in turn increased the buildup of polyP. In addition, phoU inactivation had several pleiotropic effects, such as reduced growth rate and yield and increased sensitivity to antibiotics and stresses. However, biofilm formation was not affected by the phoU mutation.
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Proteome-wide lysine acetylation profiling of the human pathogen Mycobacterium tuberculosis. Int J Biochem Cell Biol 2015; 59:193-202. [DOI: 10.1016/j.biocel.2014.11.010] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Revised: 10/05/2014] [Accepted: 11/21/2014] [Indexed: 12/15/2022]
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Lee SJ, Park YS, Kim SJ, Lee BJ, Suh SW. Crystal structure of PhoU from Pseudomonas aeruginosa, a negative regulator of the Pho regulon. J Struct Biol 2014; 188:22-9. [PMID: 25220976 DOI: 10.1016/j.jsb.2014.08.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 08/26/2014] [Accepted: 08/28/2014] [Indexed: 11/27/2022]
Abstract
In Escherichia coli, seven genes (pstS, pstC, pstA, pstB, phoU, phoR, and phoB) are involved in sensing environmental phosphate (Pi) and controlling the expression of the Pho regulon. PhoU is a negative regulator of the Pi-signaling pathway and modulates Pi transport through Pi transporter proteins (PstS, PstC, PstA, and PstB) through the two-component system PhoR and PhoB. Inactivation of PhoY2, one of the two PhoU homologs in Mycobacterium tuberculosis, causes defects in persistence phenotypes and increased susceptibility to antibiotics and stresses. Despite the important biological role, the mechanism of PhoU function is still unknown. Here we have determined the crystal structure of PhoU from Pseudomonas aeruginosa. It exists as a dimer in the crystal, with each monomer consisting of two structurally similar three-helix bundles. Our equilibrium sedimentation measurements support the reversible monomer-dimer equilibrium model in which P. aeruginosa PhoU exists in solution predominantly as dimers, with monomers in a minor fraction, at low protein concentrations. The dissociation constant for PhoU dimerization is 3.2×10(-6)M. The overall structure of P. aeruginosa PhoU dimer resembles those of Aquifex aeolicus PhoU and Thermotoga maritima PhoU2. However, it shows distinct structural features in some loops and the dimerization pattern.
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Affiliation(s)
- Sang Jae Lee
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea; Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 151-742, Republic of Korea
| | - Ye Seol Park
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea
| | - Soon-Jong Kim
- Department of Chemistry, Mokpo National University, Chonnam 534-729, Republic of Korea
| | - Bong-Jin Lee
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea.
| | - Se Won Suh
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 151-742, Republic of Korea; Department of Biophysics and Chemical Biology, College of Natural Sciences, Seoul National University, Seoul 151-742, Republic of Korea.
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Persisters, persistent infections and the Yin-Yang model. Emerg Microbes Infect 2014; 3:e3. [PMID: 26038493 PMCID: PMC3913823 DOI: 10.1038/emi.2014.3] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 10/30/2013] [Accepted: 11/26/2013] [Indexed: 12/15/2022]
Abstract
Persisters are a small fraction of quiescent bacterial cells that survive lethal antibiotics or stresses but can regrow under appropriate conditions. Persisters underlie persistent and latent infections and post-treatment relapse, posing significant challenges for the treatment of many bacterial infections. The current definition of persisters has drawbacks, and a Yin–Yang model is proposed to describe the heterogeneous nature of persisters that have to be defined in highly specific conditions. Despite their discovery more than 70 years ago, the mechanisms of persisters are poorly understood. Recent studies have identified a number of genes and pathways that shed light on the mechanisms of persister formation or survival. These include toxin–antitoxin modules, stringent response, DNA repair or protection, phosphate metabolism, alternative energy production, efflux, anti-oxidative defense and macromolecule degradation. More sensitive single-cell techniques are required for a better understanding of persister mechanisms. Studies of bacterial persisters have parallels in other microbes (fungi, parasites, viruses) and cancer stem cells in terms of mechanisms and treatment approaches. New drugs and vaccines targeting persisters are critical for improved treatment of persistent infections and perhaps cancers. Novel treatment strategies for persisters and persistent infections are discussed.
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Wu X, Hurdle JG. The Membrane as a Novel Target Site for Antibiotics to Kill Persisting Bacterial Pathogens. Antibiotics (Basel) 2013. [DOI: 10.1002/9783527659685.ch8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Yan Q, Sreedharan A, Wei S, Wang J, Pelz-Stelinski K, Folimonova S, Wang N. Global gene expression changes in Candidatus Liberibacter asiaticus during the transmission in distinct hosts between plant and insect. MOLECULAR PLANT PATHOLOGY 2013; 14:391-404. [PMID: 23336388 PMCID: PMC6638839 DOI: 10.1111/mpp.12015] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Huanglongbing (HLB) or citrus greening disease is a destructive disease of citrus worldwide, which is associated with Candidatus Liberibacter asiaticus. This phloem-limited fastidious pathogen is transmitted by the Asian citrus psyllid, Diaphorina citri, and appears to be an intracellular pathogen that maintains an intimate association with the psyllid or the plant throughout its life cycle. The molecular basis of the interaction of this pathogen with its hosts is not well understood. We hypothesized that, during infection, Ca. L. asiaticus differentially expresses the genes critical for its survival and/or pathogenicity in either host. To test this hypothesis, quantitative reverse transcription-polymerase chain reaction was performed to compare the gene expression of Ca. L. asiaticus in planta and in psyllid. Overall, 381 genes were analysed for their gene expression in planta and in psyllid. Among them, 182 genes were up-regulated in planta compared with in psyllid (P < 0.05), 16 genes were up-regulated in psyllid (P < 0.05) and 183 genes showed no statistically significant difference (P ≥ 0.05) in expression between in planta and in psyllid. Our study indicates that the expression of the Ca. L. asiaticus genes involved in transcriptional regulation, transport system, secretion system, flagella assembly, metabolic pathway and stress resistance are changed significantly in a host-specific manner to adapt to the distinct environments of plant and insect. To our knowledge, this is the first large-scale study to evaluate the differential expression of Ca. L. asiaticus genes in a plant host and its insect vector.
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Affiliation(s)
- Qing Yan
- Department of Microbiology and Cell Science, Citrus Research and Education Center, IFAS, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA
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PhoY2 of mycobacteria is required for metabolic homeostasis and stress response. J Bacteriol 2012; 195:243-52. [PMID: 23123909 DOI: 10.1128/jb.01556-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ability of pathogenic mycobacteria to adapt to diverse environments is essential for their success as pathogens. Here we describe a transposon-inactivated phoY2 mutant of Mycobacterium marinum. PhoY2 of mycobacteria is a functional homologue of PhoU in Escherichia coli and an important component of the Pho regulon. We found that PhoY2 is required for maintaining intracellular inorganic phosphate (P(i)) homeostasis and balanced energy and redox states. Disruption of phoY2 resulted in elevated levels of intracellular poly-P(i) and ATP and an elevated NAD(+)/NADH ratio, and the mutant strain exhibited increased sensitivity to environmental stress conditions, including nutrient deprivation as well as SDS and antibiotic treatments. Taken together, our results suggest that PhoY2 is required for maintaining metabolic homeostasis and adaptation to stress conditions, which may provide an explanation for the suggested role of PhoY2 in drug tolerance.
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Forrellad MA, Klepp LI, Gioffré A, Sabio y García J, Morbidoni HR, de la Paz Santangelo M, Cataldi AA, Bigi F. Virulence factors of the Mycobacterium tuberculosis complex. Virulence 2012; 4:3-66. [PMID: 23076359 PMCID: PMC3544749 DOI: 10.4161/viru.22329] [Citation(s) in RCA: 368] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The Mycobacterium tuberculosis complex (MTBC) consists of closely related species that cause tuberculosis in both humans and animals. This illness, still today, remains to be one of the leading causes of morbidity and mortality throughout the world. The mycobacteria enter the host by air, and, once in the lungs, are phagocytated by macrophages. This may lead to the rapid elimination of the bacillus or to the triggering of an active tuberculosis infection. A large number of different virulence factors have evolved in MTBC members as a response to the host immune reaction. The aim of this review is to describe the bacterial genes/proteins that are essential for the virulence of MTBC species, and that have been demonstrated in an in vivo model of infection. Knowledge of MTBC virulence factors is essential for the development of new vaccines and drugs to help manage the disease toward an increasingly more tuberculosis-free world.
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Abstract
Mycobacterial persisters, the survivors from antibiotic exposure, necessitate the lengthy treatment of tuberculosis (TB) and pose a significant challenge for our control of the disease. We suggest that persisters in TB are heterogeneous in nature and comprise various proportions of the population depending on the circumstances; the mechanisms of their formation are complex and may be related to those required for persistence in chronic infection. Results from recent studies implicate multiple pathways for persister formation, including energy production, the stringent response, global regulators, the trans-translation pathway, proteasomal protein degradation, toxin-antitoxin modules, and transporter or efflux mechanisms. A combination of specifically persister-targeted approaches, such as catching them when active and susceptible either by stimulating them to "wake up" or by intermittent drug dosing, the development of new drugs, the use of appropriate drug combinations, and combined chemotherapy and immunotherapy, may be needed for more effective elimination of persisters and better treatment of TB. Variations in levels of persister formation and in host genetics can play a role in the outcome of clinical treatment, and thus, these may entail personalized treatment regimens.
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Smith T, Wolff KA, Nguyen L. Molecular biology of drug resistance in Mycobacterium tuberculosis. Curr Top Microbiol Immunol 2012. [PMID: 23179675 DOI: 10.1007/82_2012_279] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Tuberculosis (TB) has become a curable disease, thanks to the discovery of antibiotics. However, it has remained one of the most difficult infections to treat. Most current TB regimens consist of 6-9 months of daily doses of four drugs that are highly toxic to patients. The purpose of these lengthy treatments is to completely eradicate Mycobacterium tuberculosis, notorious for its ability to resist most antibacterial agents, thereby preventing the formation of drug resistant mutants. On the contrary, the prolonged therapies have led to poor patient adherence. This, together with a severe limit of drug choices, has resulted in the emergence of strains that are increasingly resistant to the few available antibiotics. Here, we review our current understanding of molecular mechanisms underlying the profound drug resistance of M. tuberculosis. This knowledge is essential for the development of more effective antibiotics, which are not only potent against drug resistant M. tuberculosis strains but also help shorten the current treatment courses required for drug susceptible TB.
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Affiliation(s)
- Tasha Smith
- Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
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Fauvart M, De Groote VN, Michiels J. Role of persister cells in chronic infections: clinical relevance and perspectives on anti-persister therapies. J Med Microbiol 2011; 60:699-709. [PMID: 21459912 DOI: 10.1099/jmm.0.030932-0] [Citation(s) in RCA: 298] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Certain infectious diseases caused by pathogenic bacteria are typically chronic in nature. Potentially deadly examples include tuberculosis, caused by Mycobacterium tuberculosis, cystic fibrosis-associated lung infections, primarily caused by Pseudomonas aeruginosa, and candidiasis, caused by the fungal pathogen Candida albicans. A hallmark of this type of illness is the recalcitrance to treatment with antibiotics, even in the face of laboratory tests showing the causative agents to be sensitive to drugs. Recent studies have attributed this treatment failure to the presence of a small, transiently multidrug-tolerant subpopulation of cells, so-called persister cells. Here, we review our current understanding of the role that persisters play in the treatment and outcome of chronic infections. In a second part, we offer a perspective on the development of anti-persister therapies based on genes and mechanisms that have been implicated in persistence over the last decade.
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Affiliation(s)
- Maarten Fauvart
- Centre of Microbial and Plant Genetics, K.U.Leuven, Leuven, Belgium
| | | | - Jan Michiels
- Centre of Microbial and Plant Genetics, K.U.Leuven, Leuven, Belgium
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Abstract
INTRODUCTION The tuberculosis epidemic continues in much of the developing world fueled by the concurrent HIV epidemic. Due to the emergence of multidrug and extensively drug-resistant isolates of tuberculosis, there is a critical need for new drug regimens for the treatment of this disease. Currently, five new compound classes are in various stages of clinical development for tuberculosis. AREAS COVERED Selected literature from the past 5 years was reviewed and the current status of compounds in preclinical development and those compounds undergoing clinical studies in humans is described in detail as well as their known potential limitations. After a > 40-year period of almost no effort to discover and develop new therapeutics for tuberculosis, there are now significant activities by small and large pharmaceutical companies in this area. The reader will understand the current status of agents undergoing clinical evaluation for tuberculosis. EXPERT OPINION The challenge in antituberculosis drug development is to make available to patients highly effective regimens which present substantial barriers to resistance development in an affordable formulation. Shortening the length of therapy from the current 6 to 3 months or less is a goal for the newly developed regimens. For the first time in many years, there are bright prospects for improving regimens for the therapy of tuberculosis.
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Affiliation(s)
- Wing Wai Yew
- Grantham Hospital, Tuberculosis and Chest Unit, 125 Wong Chuk Hang Road, Hong Kong, China
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