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Niu H, Gu J, Zhang Y. Bacterial persisters: molecular mechanisms and therapeutic development. Signal Transduct Target Ther 2024; 9:174. [PMID: 39013893 PMCID: PMC11252167 DOI: 10.1038/s41392-024-01866-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 05/06/2024] [Accepted: 05/13/2024] [Indexed: 07/18/2024] Open
Abstract
Persisters refer to genetically drug susceptible quiescent (non-growing or slow growing) bacteria that survive in stress environments such as antibiotic exposure, acidic and starvation conditions. These cells can regrow after stress removal and remain susceptible to the same stress. Persisters are underlying the problems of treating chronic and persistent infections and relapse infections after treatment, drug resistance development, and biofilm infections, and pose significant challenges for effective treatments. Understanding the characteristics and the exact mechanisms of persister formation, especially the key molecules that affect the formation and survival of the persisters is critical to more effective treatment of chronic and persistent infections. Currently, genes related to persister formation and survival are being discovered and confirmed, but the mechanisms by which bacteria form persisters are very complex, and there are still many unanswered questions. This article comprehensively summarizes the historical background of bacterial persisters, details their complex characteristics and their relationship with antibiotic tolerant and resistant bacteria, systematically elucidates the interplay between various bacterial biological processes and the formation of persister cells, as well as consolidates the diverse anti-persister compounds and treatments. We hope to provide theoretical background for in-depth research on mechanisms of persisters and suggest new ideas for choosing strategies for more effective treatment of persistent infections.
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Affiliation(s)
- Hongxia Niu
- School of Basic Medical Science and Key Laboratory of Blood-stasis-toxin Syndrome of Zhejiang Province, Zhejiang Chinese Medical University, Hangzhou, 310053, Zhejiang, China
| | - Jiaying Gu
- School of Basic Medical Science and Key Laboratory of Blood-stasis-toxin Syndrome of Zhejiang Province, Zhejiang Chinese Medical University, Hangzhou, 310053, Zhejiang, China
| | - Ying Zhang
- State Key Laboratory for the Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310003, Zhejiang, China.
- Jinan Microecological Biomedicine Shandong Laboratory, Jinan, 250022, Shandong, China.
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2
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Kurata T, Takegawa M, Ohira T, Syroegin EA, Atkinson GC, Johansson MJO, Polikanov YS, Garcia-Pino A, Suzuki T, Hauryliuk V. Toxic Small Alarmone Synthetase FaRel2 inhibits translation by pyrophosphorylating tRNA Gly and tRNA Thr. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.05.602228. [PMID: 39005314 PMCID: PMC11245113 DOI: 10.1101/2024.07.05.602228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Translation-targeting toxic Small Alarmone Synthetases (toxSAS) are effectors of bacterial Toxin-Antitoxin systems that pyrophosphorylate the 3'-CCA end of tRNA to prevent aminoacylation. toxSAS are implicated in antiphage immunity: phage detection triggers the toxSAS activity to shut down viral production. We show that the toxSAS FaRel2 inspects the tRNA acceptor stem to specifically select tRNAGly and tRNAThr. The 1st, 2nd, 4th and 5th base pairs the stem act as the specificity determinants. We show that the toxSASs PhRel2 and CapRelSJ46 differ in tRNA specificity from FaRel2, and rationalise this through structural modelling: while the universal 3'-CCA end slots into a highly conserved CCA recognition groove, the acceptor stem recognition region is variable across toxSAS diversity. As phages use tRNA isoacceptors to overcome tRNA-targeting defences, we hypothesise that highly evolvable modular tRNA recognition allows for the escape of viral countermeasures through tRNA substrate specificity switching.
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Affiliation(s)
- Tatsuaki Kurata
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Masaki Takegawa
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo 113-8656
| | - Takayuki Ohira
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo 113-8656
| | - Egor A Syroegin
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Gemma C Atkinson
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | | | - Yury S Polikanov
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
- Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
- Center for Biomolecular Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Abel Garcia-Pino
- Cellular and Molecular Microbiology, Faculté des Sciences, Université libre de Bruxelles (ULB), Boulevard du Triomphe, Building BC, (1C4 203), 1050 Brussels, Belgium
- WELBIO, Avenue Hippocrate 75, 1200 Brussels, Belgium
| | - Tsutomu Suzuki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo 113-8656
| | - Vasili Hauryliuk
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- University of Tartu, Institute of Technology, Tartu, Estonia
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3
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Grabe GJ, Giorgio RT, Wieczór M, Gollan B, Sargen M, Orozco M, Hare SA, Helaine S. Molecular stripping underpins derepression of a toxin-antitoxin system. Nat Struct Mol Biol 2024; 31:1050-1060. [PMID: 38538913 DOI: 10.1038/s41594-024-01253-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 02/14/2024] [Indexed: 04/04/2024]
Abstract
Transcription factors control gene expression; among these, transcriptional repressors must liberate the promoter for derepression to occur. Toxin-antitoxin (TA) modules are bacterial elements that autoregulate their transcription by binding the promoter in a T:A ratio-dependent manner, known as conditional cooperativity. The molecular basis of how excess toxin triggers derepression has remained elusive, largely because monitoring the rearrangement of promoter-repressor complexes, which underpin derepression, is challenging. Here, we dissect the autoregulation of the Salmonella enterica tacAT3 module. Using a combination of assays targeting DNA binding and promoter activity, as well as structural characterization, we determine the essential TA and DNA elements required to control transcription, and we reconstitute a repression-to-derepression path. We demonstrate that excess toxin triggers molecular stripping of the repressor complex off the DNA through multiple allosteric changes causing DNA distortion and ultimately leading to derepression. Thus, our work provides important insight into the mechanisms underlying conditional cooperativity.
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Affiliation(s)
- Grzegorz J Grabe
- Department of Microbiology, Harvard Medical School, Boston, MA, USA.
| | - Rachel T Giorgio
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Miłosz Wieczór
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Bridget Gollan
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Molly Sargen
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Modesto Orozco
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Stephen A Hare
- School of Life Sciences, University of Sussex, Brighton, UK
| | - Sophie Helaine
- Department of Microbiology, Harvard Medical School, Boston, MA, USA.
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4
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Bustamante P, Ramos-Corominas MN, Martinez-Medina M. Contribution of Toxin-Antitoxin Systems to Adherent-Invasive E. coli Pathogenesis. Microorganisms 2024; 12:1158. [PMID: 38930540 PMCID: PMC11205521 DOI: 10.3390/microorganisms12061158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 05/24/2024] [Accepted: 06/05/2024] [Indexed: 06/28/2024] Open
Abstract
Pathobionts have been implicated in various chronic diseases, including Crohn's disease (CD), a multifactorial chronic inflammatory condition that primarily affects the gastrointestinal tract, causing inflammation and damage to the digestive system. While the exact cause of CD remains unclear, adherent-invasive Escherichia coli (AIEC) strains have emerged as key contributors to its pathogenesis. AIEC are characterized by their ability to adhere to and invade intestinal epithelial cells and survive and replicate inside macrophages. However, the mechanisms underlying the virulence and persistence of AIEC within their host remain the subject of intensive research. Toxin-antitoxin systems (TAs) play a potential role in AIEC pathogenesis and may be therapeutic targets. These systems generally consist of two components: a toxin harmful to the cell and an antitoxin that neutralizes the toxin's effects. They contribute to bacterial survival in adverse conditions and regulate bacterial growth and behavior, affecting various cellular processes in bacterial pathogens. This review focuses on the current information available to determine the roles of TAs in the pathogenicity of AIEC. Their contribution to the AIEC stress response, biofilm formation, phage inhibition, the maintenance of mobile genetic elements, and host lifestyles is discussed.
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Affiliation(s)
- Paula Bustamante
- Molecular and Cellular Microbiology Laboratory, Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago 8910060, Chile
| | - María Núria Ramos-Corominas
- Microbiology of Intestinal Diseases, Biology Department, Universitat de Girona, 17003 Girona, Spain; (M.N.R.-C.); (M.M.-M.)
| | - Margarita Martinez-Medina
- Microbiology of Intestinal Diseases, Biology Department, Universitat de Girona, 17003 Girona, Spain; (M.N.R.-C.); (M.M.-M.)
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Liu X, Wang P, Yuan N, Zhai Y, Yang Y, Hao M, Zhang M, Zhou D, Liu W, Jin Y, Wang A. The (p)ppGpp synthetase Rsh promotes rifampicin tolerant persister cell formation in Brucella abortus by regulating the type II toxin-antitoxin module mbcTA. Front Microbiol 2024; 15:1395504. [PMID: 38841069 PMCID: PMC11150624 DOI: 10.3389/fmicb.2024.1395504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Accepted: 05/01/2024] [Indexed: 06/07/2024] Open
Abstract
Persister cells are transiently tolerant to antibiotics and are associated with recalcitrant chronic infections due to recolonization of host cells after antibiotic removal. Brucella spp. are facultative pathogens that establish intracellular infection cycles in host cells which results in chronic persistent infections. Brucella abortus forms multi-drug persister cells which are promoted by the (p)ppGpp synthetase Rsh during rifampicin exposure. Here, we confirmed that Rsh promoted persister cells formation in B. abortus stationary phase treated with rifampicin and enrofloxacin. Deletion of the gene for Rsh decreased persister cells level in the presence of these drugs in different growth phases. However, persister cells formation by deletion strain varied in different growth phases in the presence of other antibiotics. Rsh also was involved in persister cells formation during rifampicin treatment under certain stress conditions, including acidic conditions, exposure to PBS, and heat stress. Moreover, Rsh impacted persister cell levels during rifampicin or enrofloxacin treatment in RAW264.7 macrophages. Certain typeIItoxin-antitoxin modules were upregulated under various stress conditions in B. abortus. We established that Rsh positively regulated the type II toxin-antitoxin mbcTA. Moreover, rifampicin-tolerant persister cells formation was elevated and ATP levels were decreased when mbcTA promoter was overexpressed in Rsh deletion background in stationary phase. Our results establish that (p)ppGpp synthetase Rsh plays a key role in B. abortus persistence and may serve as a potent novel target in combination with rifampicin in the development of new therapeutic approaches and prevention strategies to treat chronic infections of Brucella.
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Affiliation(s)
- Xiaofang Liu
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Pingping Wang
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Ningqiu Yuan
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Yunyi Zhai
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Yuanhao Yang
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Mingyue Hao
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Mingxing Zhang
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- College of Animal Science and Technology, Northwest A&F University, Xianyang, China
| | - Dong Zhou
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Wei Liu
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Yaping Jin
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
| | - Aihua Wang
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Xianyang, China
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6
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Fraikin N, Van Melderen L. Single-cell evidence for plasmid addiction mediated by toxin-antitoxin systems. Nucleic Acids Res 2024; 52:1847-1859. [PMID: 38224456 PMCID: PMC10899753 DOI: 10.1093/nar/gkae018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 12/22/2023] [Accepted: 01/03/2024] [Indexed: 01/16/2024] Open
Abstract
Toxin-antitoxin (TA) systems are small selfish genetic modules that increase vertical stability of their replicons. They have long been thought to stabilize plasmids by killing cells that fail to inherit a plasmid copy through a phenomenon called post-segregational killing (PSK) or addiction. While this model has been widely accepted, no direct observation of PSK was reported in the literature. Here, we devised a system that enables visualization of plasmid loss and PSK at the single-cell level using meganuclease-driven plasmid curing. Using the ccd system, we show that cells deprived of a ccd-encoding plasmid show hallmarks of DNA damage, i.e. filamentation and induction of the SOS response. Activation of ccd triggered cell death in most plasmid-free segregants, although some intoxicated cells were able to resume growth, showing that PSK-induced damage can be repaired in a SOS-dependent manner. Damage induced by ccd activates resident lambdoid prophages, which potentiate the killing effect of ccd. The loss of a model plasmid containing TA systems encoding toxins presenting various molecular mechanisms induced different morphological changes, growth arrest and loss of viability. Our experimental setup enables further studies of TA-induced phenotypes and suggests that PSK is a general mechanism for plasmid stabilization by TA systems.
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Affiliation(s)
- Nathan Fraikin
- Bacterial Genetics and Physiology, Department of Molecular Biology, Faculté des Sciences, Université Libre de Bruxelles (ULB), 6041 Gosselies, Belgium
| | - Laurence Van Melderen
- Bacterial Genetics and Physiology, Department of Molecular Biology, Faculté des Sciences, Université Libre de Bruxelles (ULB), 6041 Gosselies, Belgium
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7
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Telhig S, Pham NP, Ben Said L, Rebuffat S, Ouellette M, Zirah S, Fliss I. Exploring the genetic basis of natural resistance to microcins. Microb Genom 2024; 10:001156. [PMID: 38407259 PMCID: PMC10926693 DOI: 10.1099/mgen.0.001156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 11/28/2023] [Indexed: 02/27/2024] Open
Abstract
Enterobacteriaceae produce an arsenal of antimicrobial compounds including microcins, ribosomally produced antimicrobial peptides showing diverse structures and mechanisms of action. Microcins target close relatives of the producing strain to promote its survival. Their narrow spectrum of antibacterial activity makes them a promising alternative to conventional antibiotics, as it should decrease the probability of resistance dissemination and collateral damage to the host's microbiota. To assess the therapeutic potential of microcins, there is a need to understand the mechanisms of resistance to these molecules. In this study, we performed genomic analyses of the resistance to four microcins [microcin C, a nucleotide peptide; microcin J25, a lasso peptide; microcin B17, a linear azol(in)e-containing peptide; and microcin E492, a siderophore peptide] on a collection of 54 Enterobacteriaceae from three species: Escherichia coli, Salmonella enterica and Klebsiella pneumoniae. A gene-targeted analysis revealed that about half of the microcin-resistant strains presented mutations of genes involved in the microcin mechanism of action, especially those involved in their uptake (fhuA, fepA, cirA and ompF). A genome-wide association study did not reveal any significant correlations, yet relevant genetic elements were associated with microcin resistance. These were involved in stress responses, biofilm formation, transport systems and acquisition of immunity genes. Additionally, microcin-resistant strains exhibited several mutations within genes involved in specific metabolic pathways, especially for S. enterica and K. pneumoniae.
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Affiliation(s)
- Soufiane Telhig
- Food Science Department, Food and Agriculture Faculty, Laval University, Quebec, Canada
- Laboratoire Molécules de Communication et Adaptation des Microorganismes, Muséum national d’Histoire naturelle, Centre national de la Recherche scientifique, Paris, France
| | - Nguyen Phuong Pham
- Centre de Recherche en Infectiologie du Centre de Recherche du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec City, Québec, Canada
| | - Laila Ben Said
- Food Science Department, Food and Agriculture Faculty, Laval University, Quebec, Canada
- Institute of Nutrition and Functional Foods, Laval University, Quebec, Canada
| | - Sylvie Rebuffat
- Laboratoire Molécules de Communication et Adaptation des Microorganismes, Muséum national d’Histoire naturelle, Centre national de la Recherche scientifique, Paris, France
| | - Marc Ouellette
- Centre de Recherche en Infectiologie du Centre de Recherche du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec City, Québec, Canada
| | - Séverine Zirah
- Laboratoire Molécules de Communication et Adaptation des Microorganismes, Muséum national d’Histoire naturelle, Centre national de la Recherche scientifique, Paris, France
| | - Ismaïl Fliss
- Food Science Department, Food and Agriculture Faculty, Laval University, Quebec, Canada
- Institute of Nutrition and Functional Foods, Laval University, Quebec, Canada
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Gong J, Zeng X, Xu J, Zhang D, Dou X, Lin J, Wang C. Genomic Characterization of a Plasmid-Free and Highly Drug-Resistant Salmonella enterica Serovar Indiana Isolate in China. Vet Sci 2024; 11:46. [PMID: 38275928 PMCID: PMC10819017 DOI: 10.3390/vetsci11010046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/17/2024] [Accepted: 01/18/2024] [Indexed: 01/27/2024] Open
Abstract
The emergence of multi-drug resistant (MDR) Salmonella enterica serovar Indiana (S. Indiana) strains in China is commonly associated with the presence of one or more resistance plasmids harboring integrons pivotal in acquiring antimicrobial resistance (AMR). This study aims to elucidate the genetic makeup of this plasmid-free, highly drug-resistant S. Indiana S1467 strain. Genomic sequencing was performed using Illumina HiSeq 2500 sequencer and PacBio RS II System. Prodigal software predicted putative protein-coding sequences while BLASTP analysis was conducted. The S1467 genome comprises a circular 4,998,300 bp chromosome with an average GC content of 51.81%, encompassing 4709 open reading frames (ORFs). Fifty-four AMR genes were identified, conferring resistance across 16 AMR categories, aligning closely with the strain's antibiotic susceptibility profile. Genomic island prediction unveiled an approximately 51 kb genomic island housing a unique YeeVU toxin-antitoxin system (TAS), a rarity in Salmonella species. This suggests that the AMR gene cluster on the S1467 genomic island may stem from the integration of plasmids originating from other Enterobacteriaceae. This study contributes not only to the understanding of the genomic characteristics of a plasmid-free, highly drug-resistant S. Indiana strain but also sheds light on the intricate mechanisms underlying antimicrobial resistance. The implications of our findings extend to the broader context of horizontal gene transfer between bacterial species, emphasizing the need for continued surveillance and research to address the evolving challenges posed by drug-resistant pathogens.
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Affiliation(s)
- Jiansen Gong
- Poultry Institute, Chinese Academy of Agricultural Sciences, Yangzhou 225125, China; (J.G.); (D.Z.); (X.D.)
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Yangzhou 225009, China
| | - Ximin Zeng
- Department of Animal Science, The University of Tennessee, Knoxville, TN 37996, USA; (X.Z.); (J.L.)
| | - Jingxiao Xu
- School of Life Sciences, Fudan University, Shanghai 200438, China;
| | - Di Zhang
- Poultry Institute, Chinese Academy of Agricultural Sciences, Yangzhou 225125, China; (J.G.); (D.Z.); (X.D.)
| | - Xinhong Dou
- Poultry Institute, Chinese Academy of Agricultural Sciences, Yangzhou 225125, China; (J.G.); (D.Z.); (X.D.)
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Yangzhou 225009, China
| | - Jun Lin
- Department of Animal Science, The University of Tennessee, Knoxville, TN 37996, USA; (X.Z.); (J.L.)
| | - Chengming Wang
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA
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9
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Zhang J. Recognition of the tRNA structure: Everything everywhere but not all at once. Cell Chem Biol 2024; 31:36-52. [PMID: 38159570 PMCID: PMC10843564 DOI: 10.1016/j.chembiol.2023.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 12/02/2023] [Accepted: 12/11/2023] [Indexed: 01/03/2024]
Abstract
tRNAs are among the most abundant and essential biomolecules in cells. These spontaneously folding, extensively structured yet conformationally flexible anionic polymers literally bridge the worlds of RNAs and proteins, and serve as Rosetta stones that decipher and interpret the genetic code. Their ubiquitous presence, functional irreplaceability, and privileged access to cellular compartments and ribosomes render them prime targets for both endogenous regulation and exogenous manipulation. There is essentially no part of the tRNA that is not touched by another interaction partner, either as programmed or imposed by an external adversary. Recent progresses in genetic, biochemical, and structural analyses of the tRNA interactome produced a wealth of new knowledge into their interaction networks, regulatory functions, and molecular interfaces. In this review, I describe and illustrate the general principles of tRNA recognition by proteins and other RNAs, and discuss the underlying molecular mechanisms that deliver affinity, specificity, and functional competency.
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Affiliation(s)
- Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA.
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10
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Stojowska-Swędrzyńska K, Kuczyńska-Wiśnik D, Laskowska E. Influence of N ε-Lysine Acetylation on the Formation of Protein Aggregates and Antibiotic Persistence in E. coli. Molecules 2024; 29:383. [PMID: 38257296 PMCID: PMC10819833 DOI: 10.3390/molecules29020383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/07/2024] [Accepted: 01/10/2024] [Indexed: 01/24/2024] Open
Abstract
Numerous studies indicate that reversible Nε-lysine acetylation in bacteria may play a key role in the regulation of metabolic processes, transcription and translation, biofilm formation, virulence, and drug resistance. Using appropriate mutant strains deficient in non-enzymatic acetylation and enzymatic acetylation or deacetylation pathways, we investigated the influence of protein acetylation on cell viability, protein aggregation, and persister formation in Escherichia coli. Lysine acetylation was found to increase protein aggregation and cell viability under the late stationary phase. Moreover, increased lysine acetylation stimulated the formation of persisters. These results suggest that acetylation-dependent aggregation may improve the survival of bacteria under adverse conditions (such as the late stationary phase) and during antibiotic treatment. Further experiments revealed that acetylation-favorable conditions may increase persister formation in Klebsiella pneumoniae clinical isolate. However, the exact mechanisms underlying the relationship between acetylation and persistence in this pathogen remain to be elucidated.
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Affiliation(s)
| | | | - Ewa Laskowska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (K.S.-S.); (D.K.-W.)
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11
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Jurėnas D. Metabolic Labeling: Snapshot of the Effect of Toxins on the Key Cellular Processes. Methods Mol Biol 2024; 2715:539-545. [PMID: 37930550 DOI: 10.1007/978-1-0716-3445-5_33] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Abstract
Competing bacteria secrete vast variety of toxic effectors via secretion systems. Phospholipase, peptidoglycan-hydrolase, or pore forming toxins often manifest in the bursting of the prey cell. Other toxins reach cytoplasm of the prey where they affect cell division machinery, metabolism, nucleic acid integrity, or protein synthesis. Inhibition of cell division or DNA integrity, which summons SOS response, will often lead to bacterial cell filamentation readily observable under the microscope. However, other toxic activities will not manifest in interpretable phenotypic changes that would readily suggest their mechanism of toxicity. Activity measurements of the three fundamental cellular processes-replication, transcription and translation can pave the way for further understanding of the toxin's activity. Method commonly known as metabolic labeling makes use of radioactive precursors for DNA, RNA and protein synthesis. This method provides highly sensitive snapshot of the activity of key cellular processes.
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Affiliation(s)
- Dukas Jurėnas
- Laboratoire de Génétique et Physiologie Bactérienne, Département de Biologie Moléculaire, Faculté des Sciences, Université Libre de Bruxelles (ULB), Gosselies, Belgium.
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12
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Mattiello SP, Barth VC, Scaria J, Ferreira CAS, Oliveira SD. Fluoroquinolone and beta-lactam antimicrobials induce different transcriptome profiles in Salmonella enterica persister cells. Sci Rep 2023; 13:18696. [PMID: 37907566 PMCID: PMC10618250 DOI: 10.1038/s41598-023-46142-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 10/27/2023] [Indexed: 11/02/2023] Open
Abstract
Here, we investigate the transcriptome profiles of two S. Enteritidis and one S. Schwarzengrund isolates that present different persister levels when exposed to ciprofloxacin or ceftazidime. It was possible to note a distinct transcript profile among isolates, time of exposure, and treatment. We could not find a commonly expressed transcript profile that plays a role in persister formation after S. enterica exposure to beta-lactam or fluoroquinolone, as only three DEGs presented the same behavior under the conditions and isolates tested. It appears that the formation of persisters in S. enterica after exposure to ciprofloxacin is linked to the overexpression of genes involved in the SOS response (recA), cell division inhibitor (sulA), iron-sulfur metabolism (hscA and iscS), and type I TA system (tisB). On the other hand, most genes differentially expressed in S. enterica after exposure to ceftazidime appeared to be downregulated and were part of the flagellar assembly apparatus, citrate cycle (TCA cycle), glycolysis/gluconeogenesis, carbon metabolism, bacterial secretion system, quorum sensing, pyruvate metabolism pathway, and biosynthesis of secondary metabolites. The different transcriptome profiles found in S. enterica persisters induced by ciprofloxacin and ceftazidime suggest that these cells modulate their response differently according to each stress.
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Affiliation(s)
- S P Mattiello
- Laboratório de Imunologia e Microbiologia, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Av. Ipiranga, 6681, Porto Alegre, 90619-900, Brazil
- Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Porto Alegre, Brazil
- College of Mathematics and Science, The University of Tennessee Southern, UTS, Pulaski, TN, USA
- Department of Veterinary and Biomedical Sciences, South Dakota State University, SDSU, Brookings, SD, USA
| | - V C Barth
- Laboratório de Imunoterapia, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil
| | - J Scaria
- Department of Veterinary and Biomedical Sciences, South Dakota State University, SDSU, Brookings, SD, USA
- Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK, USA
| | - C A S Ferreira
- Laboratório de Imunologia e Microbiologia, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Av. Ipiranga, 6681, Porto Alegre, 90619-900, Brazil
- Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Porto Alegre, Brazil
| | - S D Oliveira
- Laboratório de Imunologia e Microbiologia, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Av. Ipiranga, 6681, Porto Alegre, 90619-900, Brazil.
- Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Porto Alegre, Brazil.
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Pizzolato-Cezar LR, Spira B, Machini MT. Bacterial toxin-antitoxin systems: Novel insights on toxin activation across populations and experimental shortcomings. CURRENT RESEARCH IN MICROBIAL SCIENCES 2023; 5:100204. [PMID: 38024808 PMCID: PMC10643148 DOI: 10.1016/j.crmicr.2023.100204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023] Open
Abstract
The alarming rise in hard-to-treat bacterial infections is of great concern to human health. Thus, the identification of molecular mechanisms that enable the survival and growth of pathogens is of utmost urgency for the development of more efficient antimicrobial therapies. In challenging environments, such as presence of antibiotics, or during host infection, metabolic adjustments are essential for microorganism survival and competitiveness. Toxin-antitoxin systems (TASs) consisting of a toxin with metabolic modulating activity and a cognate antitoxin that antagonizes that toxin are important elements in the arsenal of bacterial stress defense. However, the exact physiological function of TA systems is highly debatable and with the exception of stabilization of mobile genetic elements and phage inhibition, other proposed biological functions lack a broad consensus. This review aims at gaining new insights into the physiological effects of TASs in bacteria and exploring the experimental shortcomings that lead to discrepant results in TAS research. Distinct control mechanisms ensure that only subsets of cells within isogenic cultures transiently develop moderate levels of toxin activity. As a result, TASs cause phenotypic growth heterogeneity rather than cell stasis in the entire population. It is this feature that allows bacteria to thrive in diverse environments through the creation of subpopulations with different metabolic rates and stress tolerance programs.
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Affiliation(s)
- Luis R. Pizzolato-Cezar
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Beny Spira
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - M. Teresa Machini
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
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Xu X, Usher B, Gutierrez C, Barriot R, Arrowsmith TJ, Han X, Redder P, Neyrolles O, Blower TR, Genevaux P. MenT nucleotidyltransferase toxins extend tRNA acceptor stems and can be inhibited by asymmetrical antitoxin binding. Nat Commun 2023; 14:4644. [PMID: 37591829 PMCID: PMC10435456 DOI: 10.1038/s41467-023-40264-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 07/20/2023] [Indexed: 08/19/2023] Open
Abstract
Mycobacterium tuberculosis, the bacterium responsible for human tuberculosis, has a genome encoding a remarkably high number of toxin-antitoxin systems of largely unknown function. We have recently shown that the M. tuberculosis genome encodes four of a widespread, MenAT family of nucleotidyltransferase toxin-antitoxin systems. In this study we characterize MenAT1, using tRNA sequencing to demonstrate MenT1 tRNA modification activity. MenT1 activity is blocked by MenA1, a short protein antitoxin unrelated to the MenA3 kinase. X-ray crystallographic analysis shows blockage of the conserved MenT fold by asymmetric binding of MenA1 across two MenT1 protomers, forming a heterotrimeric toxin-antitoxin complex. Finally, we also demonstrate tRNA modification by toxin MenT4, indicating conserved activity across the MenT family. Our study highlights variation in tRNA target preferences by MenT toxins, selective use of nucleotide substrates, and diverse modes of MenA antitoxin activity.
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Affiliation(s)
- Xibing Xu
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Ben Usher
- Department of Biosciences, Durham University, South Road, Durham, DH1 3LE, UK
| | - Claude Gutierrez
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Roland Barriot
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Tom J Arrowsmith
- Department of Biosciences, Durham University, South Road, Durham, DH1 3LE, UK
| | - Xue Han
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Peter Redder
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Olivier Neyrolles
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Tim R Blower
- Department of Biosciences, Durham University, South Road, Durham, DH1 3LE, UK.
| | - Pierre Genevaux
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France.
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Bollen C, Louwagie E, Verstraeten N, Michiels J, Ruelens P. Environmental, mechanistic and evolutionary landscape of antibiotic persistence. EMBO Rep 2023; 24:e57309. [PMID: 37395716 PMCID: PMC10398667 DOI: 10.15252/embr.202357309] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/07/2023] [Accepted: 06/16/2023] [Indexed: 07/04/2023] Open
Abstract
Recalcitrant infections pose a serious challenge by prolonging antibiotic therapies and contributing to the spread of antibiotic resistance, thereby threatening the successful treatment of bacterial infections. One potential contributing factor in persistent infections is antibiotic persistence, which involves the survival of transiently tolerant subpopulations of bacteria. This review summarizes the current understanding of antibiotic persistence, including its clinical significance and the environmental and evolutionary factors at play. Additionally, we discuss the emerging concept of persister regrowth and potential strategies to combat persister cells. Recent advances highlight the multifaceted nature of persistence, which is controlled by deterministic and stochastic elements and shaped by genetic and environmental factors. To translate in vitro findings to in vivo settings, it is crucial to include the heterogeneity and complexity of bacterial populations in natural environments. As researchers continue to gain a more holistic understanding of this phenomenon and develop effective treatments for persistent bacterial infections, the study of antibiotic persistence is likely to become increasingly complex.
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Affiliation(s)
- Celien Bollen
- Centre of Microbial and Plant GeneticsKU LeuvenLeuvenBelgium
- Center for Microbiology, VIBLeuvenBelgium
| | - Elen Louwagie
- Centre of Microbial and Plant GeneticsKU LeuvenLeuvenBelgium
- Center for Microbiology, VIBLeuvenBelgium
| | - Natalie Verstraeten
- Centre of Microbial and Plant GeneticsKU LeuvenLeuvenBelgium
- Center for Microbiology, VIBLeuvenBelgium
| | - Jan Michiels
- Centre of Microbial and Plant GeneticsKU LeuvenLeuvenBelgium
- Center for Microbiology, VIBLeuvenBelgium
| | - Philip Ruelens
- Centre of Microbial and Plant GeneticsKU LeuvenLeuvenBelgium
- Center for Microbiology, VIBLeuvenBelgium
- Laboratory of Socioecology and Social EvolutionKU LeuvenLeuvenBelgium
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Ehrhardt K, Becker AL, Grassl GA. Determinants of persistent Salmonella infections. Curr Opin Immunol 2023; 82:102306. [PMID: 36989589 DOI: 10.1016/j.coi.2023.102306] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 03/29/2023]
Abstract
Persistent bacterial infections constitute an enormous challenge for public health. Amongst infections with other bacteria, infections with typhoidal and nontyphoidal Salmonella enterica serovars can result in long-term infections of the human and animal host. Persistent infections that are asymptomatic are difficult to identify and thus can serve as a silent reservoir for transmission. Symptomatic persistent infections are often difficult to treat as they harbor a combination of antibiotic-tolerant and antibiotic-resistant bacteria and boost the spread of genetic antibiotic resistance. In the last couple of years, the field has made some major progress in understanding the role of persisters, their reservoirs as well as their interplay with host factors in persistent Salmonella infections.
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Riffaud CM, Rucks EA, Ouellette SP. Persistence of obligate intracellular pathogens: alternative strategies to overcome host-specific stresses. Front Cell Infect Microbiol 2023; 13:1185571. [PMID: 37284502 PMCID: PMC10239878 DOI: 10.3389/fcimb.2023.1185571] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 05/05/2023] [Indexed: 06/08/2023] Open
Abstract
In adapting to the intracellular niche, obligate intracellular bacteria usually undergo a reduction of genome size by eliminating genes not needed for intracellular survival. These losses can include, for example, genes involved in nutrient anabolic pathways or in stress response. Living inside a host cell offers a stable environment where intracellular bacteria can limit their exposure to extracellular effectors of the immune system and modulate or outright inhibit intracellular defense mechanisms. However, highlighting an area of vulnerability, these pathogens are dependent on the host cell for nutrients and are very sensitive to conditions that limit nutrient availability. Persistence is a common response shared by evolutionarily divergent bacteria to survive adverse conditions like nutrient deprivation. Development of persistence usually compromises successful antibiotic therapy of bacterial infections and is associated with chronic infections and long-term sequelae for the patients. During persistence, obligate intracellular pathogens are viable but not growing inside their host cell. They can survive for a long period of time such that, when the inducing stress is removed, reactivation of their growth cycles resumes. Given their reduced coding capacity, intracellular bacteria have adapted different response mechanisms. This review gives an overview of the strategies used by the obligate intracellular bacteria, where known, which, unlike model organisms such as E. coli, often lack toxin-antitoxin systems and the stringent response that have been linked to a persister phenotype and amino acid starvation states, respectively.
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Personnic N, Doublet P, Jarraud S. Intracellular persister: A stealth agent recalcitrant to antibiotics. Front Cell Infect Microbiol 2023; 13:1141868. [PMID: 37065203 PMCID: PMC10102521 DOI: 10.3389/fcimb.2023.1141868] [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: 01/10/2023] [Accepted: 03/06/2023] [Indexed: 04/03/2023] Open
Abstract
The bulk of bacteria transiently evading appropriate antibiotic regimes and recovered from non-resolutive infections are commonly refer to as persisters. In this mini-review, we discuss how antibiotic persisters stem from the interplay between the pathogen and the cellular defenses mechanisms and its underlying heterogeneity.
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Affiliation(s)
- Nicolas Personnic
- CIRI, Centre International de Recherche en Infectiologie, CNRS UMR 5308, INSERM U1111, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Group Persistence and Single-Cell Dynamics of Respiratory Pathogens, Lyon, France
- *Correspondence: Nicolas Personnic,
| | - Patricia Doublet
- CIRI, Centre International de Recherche en Infectiologie, CNRS UMR 5308, INSERM U1111, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Group Legionella Pathogenesis, Lyon, France
| | - Sophie Jarraud
- CIRI, Centre International de Recherche en Infectiologie, CNRS UMR 5308, INSERM U1111, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Group Legionella Pathogenesis, Lyon, France
- National Reference Centre for Legionella, Institute of Infectious Agents, Hospices Civils de Lyon, Lyon, France
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19
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Lallement C, Goldring WPD, Jelsbak L. Global transcriptomic response of the AI-3 isomers 3,5-DPO and 3,6-DPO in Salmonella Typhimurium. Arch Microbiol 2023; 205:117. [PMID: 36929450 DOI: 10.1007/s00203-023-03450-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/14/2023] [Accepted: 02/23/2023] [Indexed: 03/18/2023]
Abstract
Bacterial intercellular signaling mediated by small molecules, also called autoinducers (AIs), enables synchronized behavior in response to environmental conditions, and in many bacterial pathogens, intercellular signaling controls virulence gene expression. However, in the intestinal pathogen Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium), although three signals, named AI-1, AI-2 and AI-3, have been described, their roles in virulence remain elusive. AI-3 is the 3,6- isomer of a previously described Vibrio cholerae signaling molecule; 3,5-dimethylpyrazin-2-ol (3,5-DPO). To elucidate the role of AI-3/DPO in S. Typhimurium, we have mapped the global transcriptomic responses to 3,5- and 3,6-DPO isomers in S. Typhimurium. Our studies showed that DPO affects expression of almost 8% of all genes. Specifically, expression of several genes involved in gut-colonization respond to DPO. Interestingly, most of the affected genes are similarly regulated by 3,5-DPO and 3,6-DPO, respectively, indicating that the two isomers have overlapping roles in S. Typhimurium.
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Affiliation(s)
- Claire Lallement
- Department of Sciences and Environment, Roskilde University, Roskilde, Denmark
| | | | - Lotte Jelsbak
- Department of Sciences and Environment, Roskilde University, Roskilde, Denmark.
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20
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Fang X, Allison KR. Resuscitation dynamics reveal persister partitioning after antibiotic treatment. Mol Syst Biol 2023; 19:e11320. [PMID: 36866643 PMCID: PMC10090945 DOI: 10.15252/msb.202211320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 02/10/2023] [Accepted: 02/15/2023] [Indexed: 03/04/2023] Open
Abstract
Bacteria can survive antibiotics by forming dormant, drug-tolerant persisters. Persisters can resuscitate from dormancy after treatment and prolong infections. Resuscitation is thought to occur stochastically, but its transient, single-cell nature makes it difficult to investigate. We tracked the resuscitation of individual persisters by microscopy after ampicillin treatment and, by characterizing their dynamics, discovered that Escherichia coli and Salmonella enterica persisters resuscitate exponentially rather than stochastically. We demonstrated that the key parameters controlling resuscitation map to the ampicillin concentration during treatment and efflux during resuscitation. Consistently, we observed many persister progeny have structural defects and transcriptional responses indicative of cellular damage, for both β-lactam and quinolone antibiotics. During resuscitation, damaged persisters partition unevenly, generating both healthy daughter cells and defective ones. This persister partitioning phenomenon was observed in S. enterica, Klebsiella pneumoniae, Pseudomonas aeruginosa, and an E. coli urinary tract infection (UTI) isolate. It was also observed in the standard persister assay and after in situ treatment of a clinical UTI sample. This study reveals novel properties of resuscitation and indicates that persister partitioning may be a survival strategy in bacteria that lack genetic resistance.
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Affiliation(s)
- Xin Fang
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, USA.,Department of Medicine/Division of Infectious Diseases, Emory University School of Medicine, Atlanta, GA, USA
| | - Kyle R Allison
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, USA.,Department of Medicine/Division of Infectious Diseases, Emory University School of Medicine, Atlanta, GA, USA
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Sonika S, Singh S, Mishra S, Verma S. Toxin-antitoxin systems in bacterial pathogenesis. Heliyon 2023; 9:e14220. [PMID: 37101643 PMCID: PMC10123168 DOI: 10.1016/j.heliyon.2023.e14220] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023] Open
Abstract
Toxin-Antitoxin (TA) systems are abundant in prokaryotes and play an important role in various biological processes such as plasmid maintenance, phage inhibition, stress response, biofilm formation, and dormant persister cell generation. TA loci are abundant in pathogenic intracellular micro-organisms and help in their adaptation to the harsh host environment such as nutrient deprivation, oxidation, immune response, and antimicrobials. Several studies have reported the involvement of TA loci in establishing successful infection, intracellular survival, better colonization, adaptation to host stresses, and chronic infection. Overall, the TA loci play a crucial role in bacterial virulence and pathogenesis. Nonetheless, there are some controversies about the role of TA system in stress response, biofilm and persister formation. In this review, we describe the role of the TA systems in bacterial virulence. We discuss the important features of each type of TA system and the recent discoveries identifying key contributions of TA loci in bacterial pathogenesis.
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Peptidyl tRNA Hydrolase Is Required for Robust Prolyl-tRNA Turnover in Mycobacterium tuberculosis. mBio 2023; 14:e0346922. [PMID: 36695586 PMCID: PMC9973355 DOI: 10.1128/mbio.03469-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Enzymes involved in rescuing stalled ribosomes and recycling translation machinery are ubiquitous in bacteria and required for growth. Peptidyl tRNA drop-off is a type of abortive translation that results in the release of a truncated peptide that is still bound to tRNA (peptidyl tRNA) into the cytoplasm. Peptidyl tRNA hydrolase (Pth) recycles the released tRNA by cleaving off the unfinished peptide and is essential in most bacteria. We developed a sequencing-based strategy called copper sulfate-based tRNA sequencing (Cu-tRNAseq) to study the physiological role of Pth in Mycobacterium tuberculosis (Mtb). While most peptidyl tRNA species accumulated in a strain with impaired Pth expression, peptidyl prolyl-tRNA was particularly enriched, suggesting that Pth is required for robust peptidyl prolyl-tRNA turnover. Reducing Pth levels increased Mtb's susceptibility to tRNA synthetase inhibitors that are in development to treat tuberculosis (TB) and rendered this pathogen highly susceptible to macrolides, drugs that are ordinarily ineffective against Mtb. Collectively, our findings reveal the potency of Cu-tRNAseq for profiling peptidyl tRNAs and suggest that targeting Pth would open new therapeutic approaches for TB. IMPORTANCE Peptidyl tRNA hydrolase (Pth) is an enzyme that cuts unfinished peptides off tRNA that has been prematurely released from a stalled ribosome. Pth is essential in nearly all bacteria, including the pathogen Mycobacterium tuberculosis (Mtb), but it has not been clear why. We have used genetic and novel biochemical approaches to show that when Pth levels decline in Mtb, peptidyl tRNA accumulates to such an extent that usable tRNA pools drop. Thus, Pth is needed to maintain normal tRNA levels, most strikingly for prolyl-tRNAs. Many antibiotics act on protein synthesis and could be affected by altering the availability of tRNA. This is certainly true for tRNA synthetase inhibitors, several of which are drug candidates for tuberculosis. We find that their action is potentiated by Pth depletion. Furthermore, Pth depletion results in hypersensitivity to macrolides, drugs that are not active enough under ordinary circumstances to be useful for tuberculosis.
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Yee JX, Kim J, Yeom J. Membrane Proteins as a Regulator for Antibiotic Persistence in Gram-Negative Bacteria. J Microbiol 2023; 61:331-341. [PMID: 36800168 DOI: 10.1007/s12275-023-00024-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 01/26/2023] [Accepted: 01/27/2023] [Indexed: 02/18/2023]
Abstract
Antibiotic treatment failure threatens our ability to control bacterial infections that can cause chronic diseases. Persister bacteria are a subpopulation of physiological variants that becomes highly tolerant to antibiotics. Membrane proteins play crucial roles in all living organisms to regulate cellular physiology. Although a diverse membrane component involved in persistence can result in antibiotic treatment failure, the regulations of antibiotic persistence by membrane proteins has not been fully understood. In this review, we summarize the recent advances in our understanding with regards to membrane proteins in Gram-negative bacteria as a regulator for antibiotic persistence, highlighting various physiological mechanisms in bacteria.
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Affiliation(s)
- Jia Xin Yee
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, 169857, Singapore
| | - Juhyun Kim
- School of Life Science, BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu, 41566, Republic of Korea.
| | - Jinki Yeom
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, 169857, Singapore. .,Department of Microbiology and Immunology, College of Medicine, Seoul National University, Seoul, 03080, Republic of Korea. .,Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul, 03080, Republic of Korea. .,Cancer Research Institute, Seoul National University, Seoul, 03080, Republic of Korea.
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The DarT/DarG Toxin-Antitoxin ADP-Ribosylation System as a Novel Target for a Rational Design of Innovative Antimicrobial Strategies. Pathogens 2023; 12:pathogens12020240. [PMID: 36839512 PMCID: PMC9967889 DOI: 10.3390/pathogens12020240] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/27/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
The chemical modification of cellular macromolecules by the transfer of ADP-ribose unit(s), known as ADP-ribosylation, is an ancient homeostatic and stress response control system. Highly conserved across the evolution, ADP-ribosyltransferases and ADP-ribosylhydrolases control ADP-ribosylation signalling and cellular responses. In addition to proteins, both prokaryotic and eukaryotic transferases can covalently link ADP-ribosylation to different conformations of nucleic acids, thus highlighting the evolutionary conservation of archaic stress response mechanisms. Here, we report several structural and functional aspects of DNA ADP-ribosylation modification controlled by the prototype DarT and DarG pair, which show ADP-ribosyltransferase and hydrolase activity, respectively. DarT/DarG is a toxin-antitoxin system conserved in many bacterial pathogens, for example in Mycobacterium tuberculosis, which regulates two clinically important processes for human health, namely, growth control and the anti-phage response. The chemical modulation of the DarT/DarG system by selective inhibitors may thus represent an exciting strategy to tackle resistance to current antimicrobial therapies.
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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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Bogati B, Shore SFH, Nipper TD, Stoiculescu O, Fozo EM. Charged Amino Acids Contribute to ZorO Toxicity. Toxins (Basel) 2022; 15:32. [PMID: 36668852 PMCID: PMC9860968 DOI: 10.3390/toxins15010032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 12/24/2022] [Accepted: 12/27/2022] [Indexed: 01/03/2023] Open
Abstract
Chromosomally encoded toxin-antitoxin systems have been increasingly identified and characterized across bacterial species over the past two decades. Overproduction of the toxin gene results in cell growth stasis or death for the producing cell, but co-expression of its antitoxin can repress the toxic effects. For the subcategory of type I toxin-antitoxin systems, many of the described toxin genes encode a small, hydrophobic protein with several charged residues distributed across the sequence of the toxic protein. Though these charged residues are hypothesized to be critical for the toxic effects of the protein, they have not been studied broadly across different type I toxins. Herein, we mutated codons encoding charged residues in the type I toxin zorO, from the zor-orz toxin-antitoxin system, to determine their impacts on growth inhibition, membrane depolarization, ATP depletion, and the localization of this small protein. The non-toxic variants of ZorO accumulated both in the membrane and cytoplasm, indicating that membrane localization alone is not sufficient for its toxicity. While mutation of a charged residue could result in altered toxicity, this was dependent not only on the position of the amino acid within the protein but also on the residue to which it was converted, suggesting a complex role of charged residues in ZorO-mediated toxicity. A previous study indicated that additional copies of the zor-orz system improved growth in aminoglycosides: within, we note that this improved growth is independent of ZorO toxicity. By increasing the copy number of the zorO gene fused with a FLAG-tag, we were able to detect the protein expressed from its native promoter elements: an important step for future studies of toxin expression and function.
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Affiliation(s)
| | | | | | | | - Elizabeth M. Fozo
- Department of Microbiology, University of Tennessee Knoxville, Knoxville, TN 37996, USA
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27
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Toxin-Antitoxin Systems Alter Adaptation of Mycobacterium smegmatis to Environmental Stress. Microbiol Spectr 2022; 10:e0281522. [PMID: 36318013 PMCID: PMC9769933 DOI: 10.1128/spectrum.02815-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Toxin-antitoxin (TA) systems are ubiquitous genetic elements in prokaryotes, but their biological importance is poorly understood. Mycobacterium smegmatis contains eight putative TA systems. Previously, seven TAs have been studied, with five of them being verified as functional. Here, we show that Ms0251-0252 is a novel TA system in that expression of the toxin Ms0251 leads to growth inhibition that can be rescued by the antitoxin Ms0252. To investigate the functional roles of TA systems in M. smegmatis, we deleted the eight putative TA loci and assayed the mutants for resistance to various stresses. Deletion of all eight TA loci resulted in decreased survival under starvation conditions and altered fitness when exposed to environmental stresses. Furthermore, we showed that deletion of the eight TA loci decreased resistance to phage infection in Sauton medium compared with the results using 7H10 medium, suggesting that TA systems might have different contributions depending on the nutrient environment. Furthermore, we found that MazEF specifically played a dominant role in resistance to phage infection. Finally, transcriptome analysis revealed that MazEF overexpression led to differential expression of multiple genes, including those related to iron acquisition. Altogether, we demonstrate that TA systems coordinately function to allow M. smegmatis to adapt to changing environmental conditions. IMPORTANCE Toxin-antitoxin (TA) systems are mechanisms for rapid adaptation of bacteria to environmental changes. Mycobacterium smegmatis, a model bacterium for studying Mycobacterium tuberculosis, encodes eight putative TA systems. Here, we constructed an M. smegmatis mutant with deletions of all eight TA-encoding genes and evaluated the resistance of these mutants to environmental stresses. Our results showed that different TA systems have overlapping and, in some cases, opposing functions in adaptation to various stresses. We suggest that complementary TA modules may function together to regulate the bacterial stress response, enabling adaptation to changing environments. Together, this study provides key insights into the roles of TA systems in resistance to various environmental stresses, drug tolerance, and defense against phage infection.
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Liu N, Zhu S, Deng Y, Xie M, Zhao M, Sun T, Yu C, Zhong Y, Guo R, Cheng K, Chang D, Zhu P. Construction of multifunctional hydrogel with metal-polyphenol capsules for infected full-thickness skin wound healing. Bioact Mater 2022; 24:69-80. [PMID: 36582352 PMCID: PMC9772805 DOI: 10.1016/j.bioactmat.2022.12.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/09/2022] [Accepted: 12/09/2022] [Indexed: 12/15/2022] Open
Abstract
Damaged skin cannot prevent harmful bacteria from invading tissues, causing infected wounds or even severe tissue damage. In this study, we developed a controlled-release antibacterial composite hydrogel system that can promote wound angiogenesis and inhibit inflammation by sustained releasing Cu-Epigallocatechin-3-gallate (Cu-EGCG) nano-capsules. The prepared SilMA/HAMA/Cu-EGCG hydrogel showed an obvious inhibitory effect on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). It could also promote the proliferation and migration of L929 fibroblasts. In vivo full-thickness infected wound healing experiments confirmed the angiogenesis and inflammation regulating effect. Accelerate collagen deposition and wound healing speed were also observed in the SilMA/HAMA/Cu-EGCG hydrogel treated group. The findings of this study show the great potential of this controlled-release antibacterial composite hydrogel in the application of chronic wound healing.
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Affiliation(s)
- Nanbo Liu
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510100, China,Guangdong Provincial Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Guangzhou Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Guangzhou, Guangdong, 510100, China
| | - Shuoji Zhu
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510100, China,University of Tokyo, Tokyo, 113-8666, Japan,Guangdong Provincial Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Guangzhou Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Guangzhou, Guangdong, 510100, China
| | - Yuzhi Deng
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510100, China,Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, 524001, China,Guangdong Provincial Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Guangzhou Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Guangzhou, Guangdong, 510100, China
| | - Ming Xie
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510100, China,Guangdong Provincial Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Guangzhou Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Guangzhou, Guangdong, 510100, China
| | - Mingyi Zhao
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510100, China,Guangdong Provincial Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Guangzhou Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Guangzhou, Guangdong, 510100, China
| | - Tucheng Sun
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510100, China,Guangdong Provincial Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Guangzhou Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Guangzhou, Guangdong, 510100, China
| | - Changjiang Yu
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510100, China,Guangdong Provincial Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Guangzhou Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Guangzhou, Guangdong, 510100, China
| | - Ying Zhong
- Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, 524001, China
| | - Rui Guo
- Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Guangdong Provincial Engineering and Technological Research Centre for Drug Carrier Development, Department of Biomedical Engineering, Jinan University, Guangzhou, 510632, China,Corresponding author.
| | - Keluo Cheng
- Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, 524001, China,Corresponding author.
| | - Dehua Chang
- University of Tokyo Hospital Department of Cell Therapy in Regenerative Medicine, Tokyo, 113-8666, Japan,Corresponding author.
| | - Ping Zhu
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510100, China,Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, 524001, China,Guangdong Provincial Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Guangzhou Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Guangzhou, Guangdong, 510100, China,Corresponding author. Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510100, China.
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29
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Shi X, Zarkan A. Bacterial survivors: evaluating the mechanisms of antibiotic persistence. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 36748698 DOI: 10.1099/mic.0.001266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bacteria withstand antibiotic onslaughts by employing a variety of strategies, one of which is persistence. Persistence occurs in a bacterial population where a subpopulation of cells (persisters) survives antibiotic treatment and can regrow in a drug-free environment. Persisters may cause the recalcitrance of infectious diseases and can be a stepping stone to antibiotic resistance, so understanding persistence mechanisms is critical for therapeutic applications. However, current understanding of persistence is pervaded by paradoxes that stymie research progress, and many aspects of this cellular state remain elusive. In this review, we summarize the putative persister mechanisms, including toxin-antitoxin modules, quorum sensing, indole signalling and epigenetics, as well as the reasons behind the inconsistent body of evidence. We highlight present limitations in the field and underscore a clinical context that is frequently neglected, in the hope of supporting future researchers in examining clinically important persister mechanisms.
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Affiliation(s)
- Xiaoyi Shi
- Cambridge Centre for International Research, Cambridge CB4 0PZ, UK
| | - Ashraf Zarkan
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
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30
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Cai T, Zhao QH, Xiang WL, Zhu L, Rao Y, Tang J. HigBA toxin-antitoxin system of Weissella cibaria is involved in response to the bile salt stress. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2022; 102:6749-6756. [PMID: 35633128 DOI: 10.1002/jsfa.12042] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 05/25/2022] [Accepted: 05/28/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Toxin-antitoxin (TA) systems are prevalent adaptive genetic elements in bacterial genomes, which can respond to environmental stress. While, few studies have addressed TA systems in probiotics and their roles in the adaptation to gastrointestinal transit (GIT) environments. RESULTS The Weissella cibaria 018 could survive in pH 3.0-5.0 and 0.5-3.0 g L-1 bile salt, and its HigBA system responded to the bile salt stress, but not to acid stress. The toxin protein HigB and its cognate antitoxin protein HigA had 85.1% and 100% similarity with those of Lactobacillus plantarum, respectively, and they formed the stable tetramer HigB-(HigA)2 -HigB structure in W. cibaria 018. When exposed to 1.5-3.0 g L-1 bile salt, the transcriptions of higB and higA were up-regulated with 4.39-19.29 and 5.94-30.91 folds, respectively. Meanwhile, W. cibaria 018 gathered into a mass with 48.07% survival rate and its persister cells were found to increase 8.21% under 3.0 g L-1 bile salt. CONCLUSION The HigBA TA system of W. cibaria 018 responded to the bile salt stress, but not to acid stress, which might offer novel perspectives to understand the tolerant mechanism of probiotics to GIT environment. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Ting Cai
- School of Food and Bioengineering, Xihua University, Chengdu, China
| | - Qiu-Huan Zhao
- School of Food and Bioengineering, Xihua University, Chengdu, China
| | - Wen-Liang Xiang
- School of Food and Bioengineering, Xihua University, Chengdu, China
- Key Laboratory of Food Biotechnology of Sichuan, Xihua University, Chengdu, China
| | - Lin Zhu
- School of Food and Bioengineering, Xihua University, Chengdu, China
| | - Yu Rao
- School of Food and Bioengineering, Xihua University, Chengdu, China
| | - Jie Tang
- School of Food and Bioengineering, Xihua University, Chengdu, China
- Key Laboratory of Food Biotechnology of Sichuan, Xihua University, Chengdu, China
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31
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Wiradiputra MRD, Khuntayaporn P, Thirapanmethee K, Chomnawang MT. Toxin-Antitoxin Systems: A Key Role on Persister Formation in Salmonella enterica Serovar Typhimurium. Infect Drug Resist 2022; 15:5813-5829. [PMID: 36213766 PMCID: PMC9541301 DOI: 10.2147/idr.s378157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Accepted: 09/16/2022] [Indexed: 11/05/2022] Open
Abstract
The toxin and antitoxin modules in bacteria consist of a toxin molecule that has activity to inhibit various cellular processes and its cognate antitoxin that neutralizes the toxin. This system is considered taking part in the formation of persister cells, which are a subpopulation of recalcitrant cells able to survive antimicrobial treatment without any resistance mechanisms. Importantly, persisters have been associated with long-term infections and treatment failures in healthcare settings. It is a public health concern since persisters can be involved in the evolution and dissemination of antimicrobial resistance amidst the aggravating spread of multidrug-resistant bacteria and insufficient novel antimicrobial therapy to tackle this issue. Salmonella enterica serovar Typhimurium is one of the most prevalent Salmonella serotypes in the world and is a leading cause of food-borne salmonellosis. S. Typhimurium has been known to cause persistent infection and a wealth of investigations on Salmonella persisters indicates that toxin and antitoxin modules play a role in mediating the phenotypic switch of persisters, rendering its survival ability in the presence of antimicrobial agents. In this review, we discuss findings regarding mechanisms that underly persistence in S. Typhimurium, especially the involvement of toxin and antitoxin modules.
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Affiliation(s)
- Made Rai Dwitya Wiradiputra
- Antimicrobial Resistance Interdisciplinary Group (AmRIG), Faculty of Pharmacy, Mahidol University, Bangkok, Thailand,Biopharmaceutical Sciences Program, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand
| | - Piyatip Khuntayaporn
- Antimicrobial Resistance Interdisciplinary Group (AmRIG), Faculty of Pharmacy, Mahidol University, Bangkok, Thailand,Department of Microbiology, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand
| | - Krit Thirapanmethee
- Antimicrobial Resistance Interdisciplinary Group (AmRIG), Faculty of Pharmacy, Mahidol University, Bangkok, Thailand,Department of Microbiology, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand
| | - Mullika Traidej Chomnawang
- Antimicrobial Resistance Interdisciplinary Group (AmRIG), Faculty of Pharmacy, Mahidol University, Bangkok, Thailand,Department of Microbiology, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand,Correspondence: Mullika Traidej Chomnawang, Department of Microbiology, Faculty of Pharmacy, Mahidol University, Bangkok, 10400, Thailand, Tel +66 2 644 8692, Email
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32
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Koo JS, Kang SM, Jung WM, Kim DH, Lee BJ. The Haemophilus influenzae HipBA toxin-antitoxin system adopts an unusual three-com-ponent regulatory mechanism. IUCRJ 2022; 9:625-631. [PMID: 36071804 PMCID: PMC9438503 DOI: 10.1107/s205225252200687x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 07/06/2022] [Indexed: 06/15/2023]
Abstract
Type II toxin-antitoxin (TA) systems encode two proteins: a toxin that inhibits cell growth and an antitoxin that neutralizes the toxin by direct inter-molecular protein-protein inter-actions. The bacterial HipBA TA system is implicated in persister formation. The Haemophilus influenzae HipBA TA system consists of a HipB antitoxin and a HipA toxin, the latter of which is split into two fragments, and here we investigate this novel three-com-ponent regulatory HipBA system. Structural and functional analysis revealed that HipAN corresponds to the N-ter-minal part of HipA from other bacteria and toxic HipAC is inactivated by HipAN, not HipB. This study will be helpful in understanding the detailed regulatory mechanism of the HipBAN+C system, as well as why it is constructed as a three-com-ponent system.
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Affiliation(s)
- Ji Sung Koo
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Sung-Min Kang
- College of Pharmacy, Duksung Women’s University, Seoul 01369, Republic of Korea
| | - Won-Min Jung
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Do-Hee Kim
- Jeju Research Institute of Pharmaceutical Sciences, College of Pharmacy, Jeju National University, Jeju 63243, Republic of Korea
- Interdisciplinary Graduate Program in Advanced Convergence Technology and Science, Jeju National University, Jeju 63243, Republic of Korea
| | - Bong-Jin Lee
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
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33
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Luk CH, Enninga J, Valenzuela C. Fit to dwell in many places – The growing diversity of intracellular Salmonella niches. Front Cell Infect Microbiol 2022; 12:989451. [PMID: 36061869 PMCID: PMC9433700 DOI: 10.3389/fcimb.2022.989451] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 07/25/2022] [Indexed: 11/21/2022] Open
Abstract
Salmonella enterica is capable of invading different host cell types including epithelial cells and M cells during local infection, and immune cells and fibroblasts during the subsequent systemic spread. The intracellular lifestyles of Salmonella inside different cell types are remarkable for their distinct residential niches, and their varying replication rates. To study this, researchers have employed different cell models, such as various epithelial cells, immune cells, and fibroblasts. In epithelial cells, S. Typhimurium dwells within modified endolysosomes or gains access to the host cytoplasm. In the cytoplasm, the pathogen is exposed to the host autophagy machinery or poised for rapid multiplication, whereas it grows at a slower rate or remains dormant within the endomembrane-bound compartments. The swift bimodal lifestyle is not observed in fibroblasts and immune cells, and it emerges that these cells handle intracellular S. Typhimurium through different clearance machineries. Moreover, in these cell types S. Typhimurium grows withing modified phagosomes of distinct functional composition by adopting targeted molecular countermeasures. The preference for one or the other intracellular niche and the diverse cell type-specific Salmonella lifestyles are determined by the complex interactions between a myriad of bacterial effectors and host factors. It is important to understand how this communication is differentially regulated dependent on the host cell type and on the distinct intracellular growth rate. To support the efforts in deciphering Salmonella invasion across the different infection models, we provide a systematic comparison of the findings yielded from cell culture models. We also outline the future directions towards a better understanding of these differential Salmonella intracellular lifestyles.
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Affiliation(s)
- Chak Hon Luk
- Institut Pasteur, Unité « Dynamique des interactions hôte-pathogène » and CNRS UMR3691, Université de Paris Cité, Paris, France
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, United Kingdom
- *Correspondence: Chak Hon Luk, ; Camila Valenzuela,
| | - Jost Enninga
- Institut Pasteur, Unité « Dynamique des interactions hôte-pathogène » and CNRS UMR3691, Université de Paris Cité, Paris, France
| | - Camila Valenzuela
- Institut Pasteur, Unité « Dynamique des interactions hôte-pathogène » and CNRS UMR3691, Université de Paris Cité, Paris, France
- *Correspondence: Chak Hon Luk, ; Camila Valenzuela,
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34
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Eisenreich W, Rudel T, Heesemann J, Goebel W. Link Between Antibiotic Persistence and Antibiotic Resistance in Bacterial Pathogens. Front Cell Infect Microbiol 2022; 12:900848. [PMID: 35928205 PMCID: PMC9343593 DOI: 10.3389/fcimb.2022.900848] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 06/21/2022] [Indexed: 12/15/2022] Open
Abstract
Both, antibiotic persistence and antibiotic resistance characterize phenotypes of survival in which a bacterial cell becomes insensitive to one (or even) more antibiotic(s). However, the molecular basis for these two antibiotic-tolerant phenotypes is fundamentally different. Whereas antibiotic resistance is genetically determined and hence represents a rather stable phenotype, antibiotic persistence marks a transient physiological state triggered by various stress-inducing conditions that switches back to the original antibiotic sensitive state once the environmental situation improves. The molecular basics of antibiotic resistance are in principle well understood. This is not the case for antibiotic persistence. Under all culture conditions, there is a stochastically formed, subpopulation of persister cells in bacterial populations, the size of which depends on the culture conditions. The proportion of persisters in a bacterial population increases under different stress conditions, including treatment with bactericidal antibiotics (BCAs). Various models have been proposed to explain the formation of persistence in bacteria. We recently hypothesized that all physiological culture conditions leading to persistence converge in the inability of the bacteria to re-initiate a new round of DNA replication caused by an insufficient level of the initiator complex ATP-DnaA and hence by the lack of formation of a functional orisome. Here, we extend this hypothesis by proposing that in this persistence state the bacteria become more susceptible to mutation-based antibiotic resistance provided they are equipped with error-prone DNA repair functions. This is - in our opinion - in particular the case when such bacterial populations are exposed to BCAs.
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Affiliation(s)
- Wolfgang Eisenreich
- Bavarian NMR Center – Structural Membrane Biochemistry, Department of Chemistry, Technische Universität München, Garching, Germany
- *Correspondence: Wolfgang Eisenreich,
| | - Thomas Rudel
- Chair of Microbiology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Jürgen Heesemann
- Max von Pettenkofer-Institute, Ludwig Maximilian University of Munich, München, Germany
| | - Werner Goebel
- Max von Pettenkofer-Institute, Ludwig Maximilian University of Munich, München, Germany
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35
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Golmoradi Zadeh R, Mirshekar M, Sadeghi Kalani B, Pourghader J, Barati M, Masjedian Jazi F. The expression of type II TA system genes following persister cell formation in Pseudomonas aeruginosa isolates in the exponential and stationary phases. Arch Microbiol 2022; 204:451. [PMID: 35781545 DOI: 10.1007/s00203-022-03038-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 05/30/2022] [Accepted: 06/01/2022] [Indexed: 11/02/2022]
Abstract
Failure of infection therapy in the presence of antibiotics has become a major problem which has been mostly attributed to the ability of bacterial persister cell formation. Bacteria use various mechanisms to form persister cells in different phases, among which is the toxin-antitoxin (TA) systems. This study aimed at investigating the expression of type II TA system genes under the stress of ciprofloxacin and colistin antibiotics in the exponential and stationary phases. To determine the effects of ciprofloxacin and colistin on persister cell formation in the exponential and stationary phases of Pseudomonas aeruginosa strains, colony counting was performed at different time intervals in the presence of fivefold MIC of ciprofloxacin and colistin. In addition, the expression of relBE, Xre-COG5654, vapBC, and Xre-GNAT genes in P. aeruginosa isolates was assessed 3.5 h after antibiotic treatment in the exponential and stationary phases using qRT-PCR. Our results indicated the presence of persister phenotype of P. aeruginosa strains in the presence of fivefold MIC of ciprofloxacin and colistin compared to the control after 3.5 h of incubation in the exponential and stationary phases. Also, the number of persister cells in the stationary phase was higher than that of the exponential phase. According to the results of qRT-PCR, ciprofloxacin and colistin may induce persister cells by increasing the expression of type II TA systems in stationary and exponential phases. Ciprofloxacin and colistin may increase the formation of persister cells by affecting the expression of type II TA systems.
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Affiliation(s)
- Rezvan Golmoradi Zadeh
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Maryam Mirshekar
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Behrooz Sadeghi Kalani
- Department of Microbiology, School of Medicine, Ilam University of Medical Science, Ilam, Iran.,Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Johar Pourghader
- Mechanical Engineering Department, Binghamton University, Binghamton, NY, 13902, USA
| | - Mahmood Barati
- Cellular and Molecular Research Center, Iran University of Medical Science, Tehran, Iran.,Department of Medical Biotechnology, Faculty of Allied Medicine, Iran University of Medical Science, Tehran, Iran
| | - Faramarz Masjedian Jazi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
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36
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Tomasi FG, Hall AMJ, Schweber JTP, Dulberger CL, McGowen K, Liu Q, Fortune SM, Helaine S, Rubin EJ. A tRNA-Acetylating Toxin and Detoxifying Enzyme in Mycobacterium tuberculosis. Microbiol Spectr 2022; 10:e0058022. [PMID: 35638832 PMCID: PMC9241777 DOI: 10.1128/spectrum.00580-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 05/02/2022] [Indexed: 11/20/2022] Open
Abstract
Toxin-antitoxin (TA) systems allow bacteria to adapt to changing environments without altering gene expression. Despite being overrepresented in Mycobacterium tuberculosis, their physiological roles remain elusive. We describe a TA system in M. tuberculosis which we named TacAT due to its homology to previously discovered systems in Salmonella. The toxin, TacT, blocks growth by acetylating glycyl-tRNAs and inhibiting translation. Its effects are reversed by the enzyme peptidyl tRNA hydrolase (Pth), which also cleaves peptidyl tRNAs that are prematurely released from stalled ribosomes. Pth is essential in most bacteria and thereby has been proposed as a promising drug target for complex pathogens like M. tuberculosis. Transposon sequencing data suggest that the tacAT operon is nonessential for M. tuberculosis growth in vitro, and premature stop mutations in this TA system present in some clinical isolates suggest that it is also dispensable in vivo. We assessed whether TacT modulates pth essentiality in M. tuberculosis because drugs targeting Pth might prompt resistance if TacAT is disrupted. We show that pth essentiality is unaffected by the absence of tacAT. These results highlight a fundamental aspect of mycobacterial biology and indicate that Pth's essential role hinges on its peptidyl-tRNA hydrolase activity. Our work underscores Pth's potential as a viable target for new antibiotics. IMPORTANCE The global rise in antibiotic-resistant tuberculosis has prompted an urgent search for new drugs. Toxin-antitoxin (TA) systems allow bacteria to adapt rapidly to environmental changes, and Mycobacterium tuberculosis encodes more TA systems than any known pathogen. We have characterized a new TA system in M. tuberculosis: the toxin, TacT, acetylates charged tRNA to block protein synthesis. TacT's effects are reversed by the essential bacterial enzyme peptidyl tRNA hydrolase (Pth), which is currently being explored as an antibiotic target. Pth also cleaves peptidyl tRNAs that are prematurely released from stalled ribosomes. We assessed whether TacT modulates pth essentiality in M. tuberculosis because drugs targeting Pth might prompt resistance if TacT is disrupted. We show that pth essentiality is unaffected by the absence of this TA system, indicating that Pth's essential role hinges on its peptidyl-tRNA hydrolase activity. Our work underscores Pth's potential as a viable target for new antibiotics.
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Affiliation(s)
- Francesca G. Tomasi
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
| | | | - Jessica T. P. Schweber
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Charles L. Dulberger
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Kerry McGowen
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Qingyun Liu
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Sarah M. Fortune
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Sophie Helaine
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Eric J. Rubin
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
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Comparative Analysis of Diverse Acetyltransferase-Type Toxin-Antitoxin Loci in Klebsiella pneumoniae. Microbiol Spectr 2022; 10:e0032022. [PMID: 35703555 PMCID: PMC9431474 DOI: 10.1128/spectrum.00320-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Toxin-antitoxin (TA) modules containing a Gcn5-related N-acetyltransferase (GNAT) toxin domain regulate bacterial physiology under adverse environmental stresses. Multiple GNAT-ribbon-helix-helix domain (RHH) TA loci have been identified in single bacterial genomes. However, their diversity and interactions are still obscure. Our previous analysis showed that the GNAT toxin of Klebsiella pneumoniae, KacT, introduces antibiotic tolerance and the toxicity of GNAT is neutralized by KacA, an RHH antitoxin. We here present a phylogenetic analysis of GNAT toxins of more than 1,000 GNAT-RHH pairs detected in completely sequenced K. pneumoniae genomes, revealing that the GNAT toxins are diverse and grouped into four distinct clades. Overexpression of GNAT toxins representative of each of the four clades halts the cell growth of K. pneumoniae, while the coexpression of the cognate RHH antitoxin neutralizes GNAT toxicity. We also identify point mutations that inactivate the GNAT toxins. Moreover, we observe a cross-interaction between GNAT-RHH pairs encoded by different replicons, where a chromosomal toxin (KacT2) can be neutralized by its cognate RHH antitoxin (KacA2 on a chromosome) and another antitoxin (KacA3 on a plasmid). Finally, statistical analysis of the distribution of GNAT-RHH loci in K. pneumoniae strains shows pronounced deviation from random distribution within the same clades. Moreover, we also obtain statistically significant correlations between different clades, which we discuss in terms of the experimental results. IMPORTANCE Elucidating the roles of multifaceted GNAT-RHH TA loci is essential for understanding how these TAs interact among themselves. Recently, the reaction mechanisms and structures of several GNAT-RHH pairs have been reported. While bacterial strains can carry multiple GNAT-RHH loci with diverse origins, studies on the possible cross-interactions of these TA pairs are still limited. Here, we find that 1,000 predicted GNAT toxins of K. pneumoniae can be grouped into four distinct clades. The distributions of TA loci within these clades in K. pneumoniae strains are highly nonrandom, with the presence of a single locus of each clade per strain being highly overrepresented. Moreover, the toxicity of a GNAT toxin encoded by a chromosome was alleviated by a noncognate RHH antitoxin on a plasmid. These results might yield a profound understanding of the widespread GNAT-RHH TA pairs and the cross-interactions between noncognate TA pairs located on different replicons.
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Bikmetov D, Hall AMJ, Livenskyi A, Gollan B, Ovchinnikov S, Gilep K, Kim J, Larrouy-Maumus G, Zgoda V, Borukhov S, Severinov K, Helaine S, Dubiley S. GNAT toxins evolve toward narrow tRNA target specificities. Nucleic Acids Res 2022; 50:5807-5817. [PMID: 35609997 PMCID: PMC9177977 DOI: 10.1093/nar/gkac356] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 04/10/2022] [Accepted: 05/05/2022] [Indexed: 12/16/2022] Open
Abstract
Type II toxin–antitoxin (TA) systems are two-gene modules widely distributed among prokaryotes. GNAT toxins associated with the DUF1778 antitoxins represent a large family of type II TAs. GNAT toxins inhibit cell growth by disrupting translation via acetylation of aminoacyl-tRNAs. In this work, we explored the evolutionary trajectory of GNAT toxins. Using LC/MS detection of acetylated aminoacyl-tRNAs combined with ribosome profiling, we systematically investigated the in vivo substrate specificity of an array of diverse GNAT toxins. Our functional data show that the majority of GNAT toxins are specific to Gly-tRNA isoacceptors. However, the phylogenetic analysis shows that the ancestor of GNAT toxins was likely a relaxed specificity enzyme capable of acetylating multiple elongator tRNAs. Together, our data provide a remarkable snapshot of the evolution of substrate specificity.
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Affiliation(s)
| | | | - Alexei Livenskyi
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119992, Russia
| | - Bridget Gollan
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Stepan Ovchinnikov
- Center for Life Sciences, Skolkovo Institute of Science and Technology, Skolkovo 143025, Russia
| | - Konstantin Gilep
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Jenny Y Kim
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Gerald Larrouy-Maumus
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Viktor Zgoda
- Institute of Biomedical Chemistry, Moscow 119435, Russia
| | - Sergei Borukhov
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084-1489, USA
| | | | | | - Svetlana Dubiley
- To whom correspondence should be addressed. Tel: +7 499 135 6089;
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39
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Abstract
Toxin-antitoxin (TA) systems are ubiquitous genetic elements in bacteria that consist of a growth-inhibiting toxin and its cognate antitoxin. These systems are prevalent in bacterial chromosomes, plasmids, and phage genomes, but individual systems are not highly conserved, even among closely related strains. The biological functions of TA systems have been controversial and enigmatic, although a handful of these systems have been shown to defend bacteria against their viral predators, bacteriophages. Additionally, their patterns of conservation-ubiquitous, but rapidly acquired and lost from genomes-as well as the co-occurrence of some TA systems with known phage defense elements are suggestive of a broader role in mediating phage defense. Here, we review the existing evidence for phage defense mediated by TA systems, highlighting how toxins are activated by phage infection and how toxins disrupt phage replication. We also discuss phage-encoded systems that counteract TA systems, underscoring the ongoing coevolutionary battle between bacteria and phage. We anticipate that TA systems will continue to emerge as central players in the innate immunity of bacteria against phage. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Michele LeRoux
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA;
| | - Michael T Laub
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; .,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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40
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Edelmann D, Berghoff BA. A Shift in Perspective: A Role for the Type I Toxin TisB as Persistence-Stabilizing Factor. Front Microbiol 2022; 13:871699. [PMID: 35369430 PMCID: PMC8969498 DOI: 10.3389/fmicb.2022.871699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 02/28/2022] [Indexed: 11/13/2022] Open
Abstract
Bacterial persistence is a phenomenon that is founded by the existence of a subpopulation of multidrug-tolerant cells. These so-called persister cells endure otherwise lethal stress situations and enable restoration of bacterial populations upon return to favorable conditions. Persisters are especially notorious for their ability to survive antibiotic treatments without conventional resistance genes and to cause infection relapse. The persister state is typically correlated with reduction or inhibition of cellular activity. Early on, chromosomal toxin-antitoxin (TA) systems were suspected to induce the persister state in response to environmental stress. However, this idea has been challenged during the last years. Especially the involvement of toxins from type II TA systems in persister formation is put into question. For toxins from type I TA systems the debate has just started. Here, we would like to summarize recent knowledge gained for the type I TA system tisB/istR-1 from Escherichia coli. TisB is a small, membrane-targeting toxin, which disrupts the proton motive force (PMF), leading to membrane depolarization. Based on experimental data, we hypothesize that TisB primarily stabilizes the persister state through depolarization and further, secondary effects. We will present a simple model that will provide a framework for future directions.
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41
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Wangkheimayum J, Chanda DD, Bhattacharjee A. Expression of itaT toxin gene is enhanced under aminoglycoside stress in Escherichia coli harbouring aac(6′)Ib. GENE REPORTS 2022. [DOI: 10.1016/j.genrep.2022.101526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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42
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Transcription-coupled DNA repair underlies variation in persister awakening and the emergence of resistance. Cell Rep 2022; 38:110427. [PMID: 35235801 DOI: 10.1016/j.celrep.2022.110427] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 01/12/2022] [Accepted: 02/01/2022] [Indexed: 11/21/2022] Open
Abstract
Persisters constitute a population of temporarily antibiotic-tolerant variants in an isogenic bacterial population and are considered an important cause of relapsing infections. It is currently unclear how cellular damage inflicted by antibiotic action is reversed upon persister state exit and how this relates to antibiotic resistance development at the molecular level. We demonstrate that persisters, upon fluoroquinolone treatment, accumulate oxidative DNA damage, which is repaired through nucleotide excision repair. Detection of the damage occurs via transcription-coupled repair using UvrD-mediated backtracking or Mfd-controlled displacement of the RNA polymerase. This competition results in heterogeneity in persister awakening lags. Most persisters repair the oxidative DNA damage, displaying a mutation rate equal to the untreated population. However, the promutagenic factor Mfd increases the mutation rate in a persister subpopulation. Our data provide in-depth insight into the molecular mechanisms underlying persister survival and pinpoint Mfd as an important molecular factor linking persistence to resistance development.
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43
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Van den Bergh B, Schramke H, Michiels JE, Kimkes TEP, Radzikowski JL, Schimpf J, Vedelaar SR, Burschel S, Dewachter L, Lončar N, Schmidt A, Meijer T, Fauvart M, Friedrich T, Michiels J, Heinemann M. Mutations in respiratory complex I promote antibiotic persistence through alterations in intracellular acidity and protein synthesis. Nat Commun 2022; 13:546. [PMID: 35087069 PMCID: PMC8795404 DOI: 10.1038/s41467-022-28141-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 01/04/2022] [Indexed: 11/28/2022] Open
Abstract
Antibiotic persistence describes the presence of phenotypic variants within an isogenic bacterial population that are transiently tolerant to antibiotic treatment. Perturbations of metabolic homeostasis can promote antibiotic persistence, but the precise mechanisms are not well understood. Here, we use laboratory evolution, population-wide sequencing and biochemical characterizations to identify mutations in respiratory complex I and discover how they promote persistence in Escherichia coli. We show that persistence-inducing perturbations of metabolic homeostasis are associated with cytoplasmic acidification. Such cytoplasmic acidification is further strengthened by compromised proton pumping in the complex I mutants. While RpoS regulon activation induces persistence in the wild type, the aggravated cytoplasmic acidification in the complex I mutants leads to increased persistence via global shutdown of protein synthesis. Thus, we propose that cytoplasmic acidification, amplified by a compromised complex I, can act as a signaling hub for perturbed metabolic homeostasis in antibiotic persisters.
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Affiliation(s)
- Bram Van den Bergh
- Centre of Microbial and Plant Genetics, Department of Molecular and Microbial Systems, KU Leuven, Leuven, Belgium
- Center for Microbiology, Flanders Institute for Biotechnology, VIB, Leuven, Belgium
- Department of Entomology, Cornell University, Ithaca, NY, USA
| | - Hannah Schramke
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen, The Netherlands
| | - Joran Elie Michiels
- Centre of Microbial and Plant Genetics, Department of Molecular and Microbial Systems, KU Leuven, Leuven, Belgium
- Center for Microbiology, Flanders Institute for Biotechnology, VIB, Leuven, Belgium
| | - Tom E P Kimkes
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen, The Netherlands
| | - Jakub Leszek Radzikowski
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen, The Netherlands
| | - Johannes Schimpf
- Molecular Bioenergetics, Institute of Biochemistry, Albert-Ludwigs-University of Freiburg, Freiburg im Breisgau, Germany
| | - Silke R Vedelaar
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen, The Netherlands
| | - Sabrina Burschel
- Molecular Bioenergetics, Institute of Biochemistry, Albert-Ludwigs-University of Freiburg, Freiburg im Breisgau, Germany
| | - Liselot Dewachter
- Centre of Microbial and Plant Genetics, Department of Molecular and Microbial Systems, KU Leuven, Leuven, Belgium
- Center for Microbiology, Flanders Institute for Biotechnology, VIB, Leuven, Belgium
| | - Nikola Lončar
- Molecular Enzymology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen, The Netherlands
| | - Alexander Schmidt
- Proteomics Core Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - Tim Meijer
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen, The Netherlands
| | - Maarten Fauvart
- Centre of Microbial and Plant Genetics, Department of Molecular and Microbial Systems, KU Leuven, Leuven, Belgium
- Center for Microbiology, Flanders Institute for Biotechnology, VIB, Leuven, Belgium
- imec, Leuven, Belgium
| | - Thorsten Friedrich
- Molecular Bioenergetics, Institute of Biochemistry, Albert-Ludwigs-University of Freiburg, Freiburg im Breisgau, Germany
| | - Jan Michiels
- Centre of Microbial and Plant Genetics, Department of Molecular and Microbial Systems, KU Leuven, Leuven, Belgium.
- Center for Microbiology, Flanders Institute for Biotechnology, VIB, Leuven, Belgium.
| | - Matthias Heinemann
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen, The Netherlands.
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44
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Lateef OM, Akintubosun MO, Olaoba OT, Samson SO, Adamczyk M. Making Sense of "Nonsense" and More: Challenges and Opportunities in the Genetic Code Expansion, in the World of tRNA Modifications. Int J Mol Sci 2022; 23:938. [PMID: 35055121 PMCID: PMC8779196 DOI: 10.3390/ijms23020938] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 01/09/2023] Open
Abstract
The evolutional development of the RNA translation process that leads to protein synthesis based on naturally occurring amino acids has its continuation via synthetic biology, the so-called rational bioengineering. Genetic code expansion (GCE) explores beyond the natural translational processes to further enhance the structural properties and augment the functionality of a wide range of proteins. Prokaryotic and eukaryotic ribosomal machinery have been proven to accept engineered tRNAs from orthogonal organisms to efficiently incorporate noncanonical amino acids (ncAAs) with rationally designed side chains. These side chains can be reactive or functional groups, which can be extensively utilized in biochemical, biophysical, and cellular studies. Genetic code extension offers the contingency of introducing more than one ncAA into protein through frameshift suppression, multi-site-specific incorporation of ncAAs, thereby increasing the vast number of possible applications. However, different mediating factors reduce the yield and efficiency of ncAA incorporation into synthetic proteins. In this review, we comment on the recent advancements in genetic code expansion to signify the relevance of systems biology in improving ncAA incorporation efficiency. We discuss the emerging impact of tRNA modifications and metabolism in protein design. We also provide examples of the latest successful accomplishments in synthetic protein therapeutics and show how codon expansion has been employed in various scientific and biotechnological applications.
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Affiliation(s)
- Olubodun Michael Lateef
- Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland; (O.M.L.); (M.O.A.); (S.O.S.)
| | | | - Olamide Tosin Olaoba
- Laboratory of Functional and Structural Biochemistry, Federal University of Sao Carlos, Sao Carlos 13565-905, SP, Brazil;
| | - Sunday Ocholi Samson
- Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland; (O.M.L.); (M.O.A.); (S.O.S.)
| | - Malgorzata Adamczyk
- Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland; (O.M.L.); (M.O.A.); (S.O.S.)
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45
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Vos MR, Piraino B, LaBreck CJ, Rahmani N, Trebino CE, Schoenle M, Peti W, Camberg JL, Page R. Degradation of the E. coli antitoxin MqsA by the proteolytic complex ClpXP is regulated by zinc occupancy and oxidation. J Biol Chem 2021; 298:101557. [PMID: 34974059 PMCID: PMC8808172 DOI: 10.1016/j.jbc.2021.101557] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 12/24/2021] [Accepted: 12/27/2021] [Indexed: 11/19/2022] Open
Abstract
It is well established that the antitoxins of toxin-antitoxin (TA) systems are selectively degraded by bacterial proteases in response to stress. However, how distinct stressors result in the selective degradation of specific antitoxins remains unanswered. MqsRA is a TA system activated by various stresses, including oxidation. Here, we reconstituted the Escherichia coli ClpXP proteolytic machinery in vitro to monitor degradation of MqsRA TA components. We show that the MqsA antitoxin is a ClpXP proteolysis substrate, and that its degradation is regulated by both zinc occupancy in MqsA and MqsR toxin binding. Using NMR chemical shift perturbation mapping, we show that MqsA is targeted directly to ClpXP via the ClpX substrate targeting N-domain, and ClpX mutations that disrupt N-domain binding inhibit ClpXP mediated degradation in vitro. Finally, we discovered that MqsA contains a cryptic N-domain recognition sequence that is accessible only in the absence of zinc and MqsR toxin, both of which stabilize the MqsA fold. This recognition sequence is transplantable and sufficient to target a fusion protein for degradation in vitro and in vivo. Based on these results, we propose a model in which stress selectively targets nascent, zinc-free MqsA, resulting in exposure of the ClpX recognition motif for ClpXP mediated degradation.
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Affiliation(s)
- Margaret R Vos
- Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut, USA; Graduate Program in Molecular Biology and Biochemistry, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Benjamin Piraino
- Department of Cell & Molecular Biology, The University of Rhode Island, Kingston, Rhode Island, USA
| | - Christopher J LaBreck
- Department of Cell & Molecular Biology, The University of Rhode Island, Kingston, Rhode Island, USA
| | - Negar Rahmani
- Department of Cell & Molecular Biology, The University of Rhode Island, Kingston, Rhode Island, USA
| | - Catherine E Trebino
- Department of Cell & Molecular Biology, The University of Rhode Island, Kingston, Rhode Island, USA
| | - Marta Schoenle
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Wolfgang Peti
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Jodi L Camberg
- Department of Cell & Molecular Biology, The University of Rhode Island, Kingston, Rhode Island, USA.
| | - Rebecca Page
- Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut, USA.
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46
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Yashiro Y, Zhang C, Sakaguchi Y, Suzuki T, Tomita K. Molecular basis of glycyl-tRNA Gly acetylation by TacT from Salmonella Typhimurium. Cell Rep 2021; 37:110130. [PMID: 34936863 DOI: 10.1016/j.celrep.2021.110130] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 10/25/2021] [Accepted: 11/23/2021] [Indexed: 10/19/2022] Open
Abstract
Bacterial toxin-antitoxin modules contribute to the stress adaptation, persistence, and dormancy of bacteria for survival under environmental stresses and are involved in bacterial pathogenesis. In Salmonella Typhimurium, the Gcn5-related N-acetyltransferase toxin TacT reportedly acetylates the α-amino groups of the aminoacyl moieties of several aminoacyl-tRNAs, inhibits protein synthesis, and promotes persister formation during the infection of macrophages. Here, we show that TacT exclusively acetylates Gly-tRNAGlyin vivo and in vitro. The crystal structure of the TacT:acetyl-Gly-tRNAGly complex and the biochemical analysis reveal that TacT specifically recognizes the discriminator U73 and G71 in tRNAGly, a combination that is only found in tRNAGly isoacceptors, and discriminates tRNAGly from other tRNA species. Thus, TacT is a Gly-tRNAGly-specific acetyltransferase toxin. The molecular basis of the specific aminoacyl-tRNA acetylation by TacT provides advanced information for the design of drugs targeting Salmonella.
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Affiliation(s)
- Yuka Yashiro
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan
| | - Chuqiao Zhang
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan
| | - Yuriko Sakaguchi
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Tsutomu Suzuki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kozo Tomita
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan.
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47
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Grabe GJ, Giorgio RT, Hall AMJ, Morgan RML, Dubois L, Sisley TA, Rycroft JA, Hare SA, Helaine S. Auxiliary interfaces support the evolution of specific toxin-antitoxin pairing. Nat Chem Biol 2021; 17:1296-1304. [PMID: 34556858 DOI: 10.1038/s41589-021-00862-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 07/20/2021] [Indexed: 02/08/2023]
Abstract
Toxin-antitoxin (TA) systems are a large family of genes implicated in the regulation of bacterial growth and its arrest in response to attacks. These systems encode nonsecreted toxins and antitoxins that specifically pair, even when present in several paralogous copies per genome. Salmonella enterica serovar Typhimurium contains three paralogous TacAT systems that block bacterial translation. We determined the crystal structures of the three TacAT complexes to understand the structural basis of specific TA neutralization and the evolution of such specific pairing. In the present study, we show that alteration of a discrete structural add-on element on the toxin drives specific recognition by their cognate antitoxin underpinning insulation of the three pairs. Similar to other TA families, the region supporting TA-specific pairing is key to neutralization. Our work reveals that additional TA interfaces beside the main neutralization interface increase the safe space for evolution of pairing specificity.
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Affiliation(s)
- Grzegorz J Grabe
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Rachel T Giorgio
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | | | | | - Laurent Dubois
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Tyler A Sisley
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Julian A Rycroft
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Stephen A Hare
- School of Life Sciences, University of Sussex, Brighton, UK
| | - Sophie Helaine
- Department of Microbiology, Harvard Medical School, Boston, MA, USA. .,MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK.
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48
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Wang M, Chan EWC, Xu C, Chen K, Yang C, Chen S. Econazole as adjuvant to conventional antibiotics is able to eradicate starvation-induced tolerant bacteria by causing proton motive force dissipation. J Antimicrob Chemother 2021; 77:425-432. [PMID: 34747463 DOI: 10.1093/jac/dkab384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 09/28/2021] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVES Bacterial antibiotic tolerance is responsible for the recalcitrance of chronic infections. This study aims to investigate a potential drug that can effectively kill antibiotic-tolerant bacteria and evaluate the ability of this drug on the eradication of tolerant cells both in vitro and in vivo. METHODS The in vitro effect of econazole on eradicating starvation-induced tolerant bacterial populations was studied by testing the amount of survival bacteria in the presence of econazole combining conventional antibiotics. Proton motive force (PMF) was determined after econazole treatment by DiOC2(3). Finally, mouse infection models were used to detect the ability of econazole on killing the tolerant populations in vivo. RESULTS Econazole eradicated starvation-induced tolerant cells of various bacterial species within 24 or 96 h when used in combination with conventional antibiotics. Moreover, mouse survival rate drastically increased along with the decrease of in vivo bacterial count after treatment of infected mice with the econazole and ceftazidime combination for 72 h. PMF was found to have dissipated almost completely in econazole-treated cells. CONCLUSIONS Econazole could act in combination with conventional antibiotics to effectively eradicate bacterial tolerant cells. The combined use of econazole and ceftazidime was shown to be effective for eradicating tolerant cells in a mouse infection model. The ability of econazole to eradicate tolerant cells was due to its ability to cause dissipation of bacterial transmembrane PMF. Econazole-mediated PMF disruption is a feasible strategy for the treatment of chronic and recurrent bacterial infections.
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Affiliation(s)
- Miaomiao Wang
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
| | - Edward Wai Chi Chan
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Chen Xu
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
| | - Kaichao Chen
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
| | - Chen Yang
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
| | - Sheng Chen
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
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49
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Jeon H, Choi E, Hwang J. Identification and characterization of VapBC toxin-antitoxin system in Bosea sp. PAMC 26642 isolated from Arctic lichens. RNA (NEW YORK, N.Y.) 2021; 27:1374-1389. [PMID: 34429367 PMCID: PMC8522696 DOI: 10.1261/rna.078786.121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
Toxin-antitoxin (TA) systems are genetic modules composed of a toxin interfering with cellular processes and its cognate antitoxin, which counteracts the activity of the toxin. TA modules are widespread in bacterial and archaeal genomes. It has been suggested that TA modules participate in the adaptation of prokaryotes to unfavorable conditions. The Bosea sp. PAMC 26642 used in this study was isolated from the Arctic lichen Stereocaulon sp. There are 12 putative type II TA loci in the genome of Bosea sp. PAMC 26642. Of these, nine functional TA systems have been shown to be toxic in Escherichia coli The toxin inhibits growth, but this inhibition is reversed when the cognate antitoxin genes are coexpressed, indicating that these putative TA loci were bona fide TA modules. Only the BoVapC1 (AXW83_01405) toxin, a homolog of VapC, showed growth inhibition specific to low temperatures, which was recovered by the coexpression of BoVapB1 (AXW83_01400). Microscopic observation and growth monitoring revealed that the BoVapC1 toxin had bacteriostatic effects on the growth of E. coli and induced morphological changes. Quantitative real time polymerase chain reaction and northern blotting analyses showed that the BoVapC1 toxin had a ribonuclease activity on the initiator tRNAfMet, implying that degradation of tRNAfMet might trigger growth arrest in E. coli Furthermore, the BoVapBC1 system was found to contribute to survival against prolonged exposure at 4°C. This is the first study to identify the function of TA systems in cold adaptation.
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Affiliation(s)
- Hyerin Jeon
- Department of Microbiology, Pusan National University, Busan 46241, Republic of Korea
| | - Eunsil Choi
- Department of Microbiology, Pusan National University, Busan 46241, Republic of Korea
- Microbiological Resource Research Institute, Pusan National University, Busan 46241, Republic of Korea
| | - Jihwan Hwang
- Department of Microbiology, Pusan National University, Busan 46241, Republic of Korea
- Microbiological Resource Research Institute, Pusan National University, Busan 46241, Republic of Korea
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Identification of Type II Toxin-Antitoxin Loci in Levilactobacillus brevis. Interdiscip Sci 2021; 14:80-88. [PMID: 34664198 DOI: 10.1007/s12539-021-00486-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/30/2021] [Accepted: 10/05/2021] [Indexed: 10/20/2022]
Abstract
Levilactobacillus brevis are present in various environments, such as beer, fermented foods, silage, and animal host. Like other lactic acid bacteria, L. brevis might adopt the viable but nonculturable (VBNC) state under unfavorable conditions. The toxin-antitoxin (TA) system, known to regulate cell growth in response to environmental stresses, is found to control the dynamic of the VBNC state. Here, we investigate the type II TA locus prevalence and compare the TA diversity in L. brevis genomes. Using the TAfinder software, we identified a total of 273 putative type II TA loci in 110 replicons of 21 completely sequenced genomes. Genome size does not appear to correlate with the amount of putative type II TA in L. brevis. Besides, type II TA loci are distributed differently among the chromosomes and plasmids. The most prevalent toxin domain is MazF-like in the chromosomes, and RelE/RelE-like in the plasmids; while for antitoxin, Xre-like and Phd-like domains are the most common in the chromosomes and plasmids, respectively. We also observed a unique GNAT-like/ArsR-like TA pair that presents only in the L. brevis chromosome. Detection of 273 putative type II TA loci in 21 complete genomes of Levilactobacillus brevis.
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