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Kunnath AP, Suodha Suoodh M, Chellappan DK, Chellian J, Palaniveloo K. Bacterial Persister Cells and Development of Antibiotic Resistance in Chronic Infections: An Update. Br J Biomed Sci 2024; 81:12958. [PMID: 39170669 PMCID: PMC11335562 DOI: 10.3389/bjbs.2024.12958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 07/25/2024] [Indexed: 08/23/2024]
Abstract
The global issue of antimicrobial resistance poses significant challenges to public health. The World Health Organization (WHO) has highlighted it as a major global health threat, causing an estimated 700,000 deaths worldwide. Understanding the multifaceted nature of antibiotic resistance is crucial for developing effective strategies. Several physiological and biochemical mechanisms are involved in the development of antibiotic resistance. Bacterial cells may escape the bactericidal actions of the drugs by entering a physiologically dormant state known as bacterial persistence. Recent findings in this field suggest that bacterial persistence can be one of the main sources of chronic infections. The antibiotic tolerance developed by the persister cells could tolerate high levels of antibiotics and may give rise to persister offspring. These persister offspring could be attributed to antibiotic resistance mechanisms, especially in chronic infections. This review attempts to shed light on persister-induced antibiotic resistance and the current therapeutic strategies.
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Affiliation(s)
- Anil Philip Kunnath
- Division of Applied Biomedical Science and Biotechnology, School of Health Sciences, International Medical University, Kuala Lumpur, Malaysia
| | - Mohamed Suodha Suoodh
- Division of Applied Biomedical Science and Biotechnology, School of Health Sciences, International Medical University, Kuala Lumpur, Malaysia
| | - Dinesh Kumar Chellappan
- Department of Life Sciences, School of Pharmacy, International Medical University, Kuala Lumpur, Malaysia
| | - Jestin Chellian
- Department of Life Sciences, School of Pharmacy, International Medical University, Kuala Lumpur, Malaysia
| | - Kishneth Palaniveloo
- Institute of Ocean and Earth Sciences, Institute for Advanced Studies Building, Universiti Malaya, Kuala Lumpur, Malaysia
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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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3
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Xu M, Liu M, Liu T, Pan X, Ren Q, Han T, Gou L. HigA2 (Rv2021c) Is a Transcriptional Regulator with Multiple Regulatory Targets in Mycobacterium tuberculosis. Microorganisms 2024; 12:1244. [PMID: 38930627 PMCID: PMC11205783 DOI: 10.3390/microorganisms12061244] [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: 05/25/2024] [Revised: 06/17/2024] [Accepted: 06/18/2024] [Indexed: 06/28/2024] Open
Abstract
Toxin-antitoxin (TA) systems are the major mechanism for persister formation in Mycobacterium tuberculosis (Mtb). Previous studies found that HigBA2 (Rv2022c-Rv2021c), a predicted type II TA system of Mtb, could be activated for transcription in response to multiple stresses such as anti-tuberculosis drugs, nutrient starvation, endure hypoxia, acidic pH, etc. In this study, we determined the binding site of HigA2 (Rv2021c), which is located in the coding region of the upstream gene higB2 (Rv2022c), and the conserved recognition motif of HigA2 was characterized via oligonucleotide mutation. Eight binding sites of HigA2 were further found in the Mtb genome according to the conserved motif. RT-PCR showed that HigA2 can regulate the transcription level of all eight of these genes and three adjacent downstream genes. DNA pull-down experiments showed that twelve functional regulators sense external regulatory signals and may regulate the transcription of the HigBA2 system. Of these, Rv0903c, Rv0744c, Rv0474, Rv3124, Rv2603c, and Rv3583c may be involved in the regulation of external stress signals. In general, we identified the downstream target genes and possible upstream regulatory genes of HigA2, which paved the way for the illustration of the persistence establishment mechanism in Mtb.
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Affiliation(s)
- Mingyan Xu
- Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, North China University of Science and Technology, Tangshan 063210, China; (M.X.); (M.L.); (T.L.); (X.P.); (Q.R.)
| | - Meikun Liu
- Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, North China University of Science and Technology, Tangshan 063210, China; (M.X.); (M.L.); (T.L.); (X.P.); (Q.R.)
| | - Tong Liu
- Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, North China University of Science and Technology, Tangshan 063210, China; (M.X.); (M.L.); (T.L.); (X.P.); (Q.R.)
| | - Xuemei Pan
- Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, North China University of Science and Technology, Tangshan 063210, China; (M.X.); (M.L.); (T.L.); (X.P.); (Q.R.)
| | - Qi Ren
- Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, North China University of Science and Technology, Tangshan 063210, China; (M.X.); (M.L.); (T.L.); (X.P.); (Q.R.)
| | - Tiesheng Han
- Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, North China University of Science and Technology, Tangshan 063210, China; (M.X.); (M.L.); (T.L.); (X.P.); (Q.R.)
| | - Lixia Gou
- School of Life Science, North China University of Science and Technology, Tangshan 063210, China
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Ramisetty S, Subbalakshmi AR, Pareek S, Mirzapoiazova T, Do D, Prabhakar D, Pisick E, Shrestha S, Achuthan S, Bhattacharya S, Malhotra J, Mohanty A, Singhal SS, Salgia R, Kulkarni P. Leveraging Cancer Phenotypic Plasticity for Novel Treatment Strategies. J Clin Med 2024; 13:3337. [PMID: 38893049 PMCID: PMC11172618 DOI: 10.3390/jcm13113337] [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: 04/22/2024] [Revised: 05/30/2024] [Accepted: 06/03/2024] [Indexed: 06/21/2024] Open
Abstract
Cancer cells, like all other organisms, are adept at switching their phenotype to adjust to the changes in their environment. Thus, phenotypic plasticity is a quantitative trait that confers a fitness advantage to the cancer cell by altering its phenotype to suit environmental circumstances. Until recently, new traits, especially in cancer, were thought to arise due to genetic factors; however, it is now amply evident that such traits could also emerge non-genetically due to phenotypic plasticity. Furthermore, phenotypic plasticity of cancer cells contributes to phenotypic heterogeneity in the population, which is a major impediment in treating the disease. Finally, plasticity also impacts the group behavior of cancer cells, since competition and cooperation among multiple clonal groups within the population and the interactions they have with the tumor microenvironment also contribute to the evolution of drug resistance. Thus, understanding the mechanisms that cancer cells exploit to tailor their phenotypes at a systems level can aid the development of novel cancer therapeutics and treatment strategies. Here, we present our perspective on a team medicine-based approach to gain a deeper understanding of the phenomenon to develop new therapeutic strategies.
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Affiliation(s)
- Sravani Ramisetty
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010, USA; (S.R.); (A.R.S.); (S.P.); (T.M.); (D.D.); (J.M.); (A.M.); (S.S.S.)
| | - Ayalur Raghu Subbalakshmi
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010, USA; (S.R.); (A.R.S.); (S.P.); (T.M.); (D.D.); (J.M.); (A.M.); (S.S.S.)
| | - Siddhika Pareek
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010, USA; (S.R.); (A.R.S.); (S.P.); (T.M.); (D.D.); (J.M.); (A.M.); (S.S.S.)
| | - Tamara Mirzapoiazova
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010, USA; (S.R.); (A.R.S.); (S.P.); (T.M.); (D.D.); (J.M.); (A.M.); (S.S.S.)
| | - Dana Do
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010, USA; (S.R.); (A.R.S.); (S.P.); (T.M.); (D.D.); (J.M.); (A.M.); (S.S.S.)
| | - Dhivya Prabhakar
- City of Hope Atlanta, 600 Celebrate Life Parkway, Newnan, GA 30265, USA;
| | - Evan Pisick
- City of Hope Chicago, 2520 Elisha Avenue, Zion, IL 60099, USA;
| | - Sagun Shrestha
- City of Hope Phoenix, 14200 West Celebrate Life Way, Goodyear, AZ 85338, USA;
| | - Srisairam Achuthan
- Center for Informatics, City of Hope National Medical Center, Duarte, CA 91010, USA;
| | - Supriyo Bhattacharya
- Integrative Genomics Core, City of Hope National Medical Center, Duarte, CA 91010, USA;
| | - Jyoti Malhotra
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010, USA; (S.R.); (A.R.S.); (S.P.); (T.M.); (D.D.); (J.M.); (A.M.); (S.S.S.)
| | - Atish Mohanty
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010, USA; (S.R.); (A.R.S.); (S.P.); (T.M.); (D.D.); (J.M.); (A.M.); (S.S.S.)
| | - Sharad S. Singhal
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010, USA; (S.R.); (A.R.S.); (S.P.); (T.M.); (D.D.); (J.M.); (A.M.); (S.S.S.)
| | - Ravi Salgia
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010, USA; (S.R.); (A.R.S.); (S.P.); (T.M.); (D.D.); (J.M.); (A.M.); (S.S.S.)
| | - Prakash Kulkarni
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010, USA; (S.R.); (A.R.S.); (S.P.); (T.M.); (D.D.); (J.M.); (A.M.); (S.S.S.)
- Department of Systems Biology, City of Hope National Medical Center, Duarte, CA 91010, USA
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Bonabal S, Darfeuille F. Preventing toxicity in toxin-antitoxin systems: An overview of regulatory mechanisms. Biochimie 2024; 217:95-105. [PMID: 37473832 DOI: 10.1016/j.biochi.2023.07.013] [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: 05/12/2023] [Revised: 07/13/2023] [Accepted: 07/17/2023] [Indexed: 07/22/2023]
Abstract
Toxin-antitoxin systems (TAs) are generally two-component genetic modules present in almost every prokaryotic genome. The production of the free and active toxin is able to disrupt key cellular processes leading to the growth inhibition or death of its host organism in absence of its cognate antitoxin. The functions attributed to TAs rely on this lethal phenotype ranging from mobile genetic elements stabilization to phage defense. Their abundance in prokaryotic genomes as well as their lethal potential make them attractive targets for new antibacterial strategies. The hijacking of TAs requires a deep understanding of their regulation to be able to design such approach. In this review, we summarize the accumulated knowledge on how bacteria cope with these toxic genes in their genome. The characterized TAs can be grouped based on the way they prevent toxicity. Some systems rely on a tight control of the expression to prevent the production of the toxin while others control the activity of the toxin at the post-translational level.
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Affiliation(s)
- Simon Bonabal
- University of Bordeaux, INSERM U1212, CNRS UMR 5320, ARNA Laboratory, F-33000, Bordeaux, France
| | - Fabien Darfeuille
- University of Bordeaux, INSERM U1212, CNRS UMR 5320, ARNA Laboratory, F-33000, Bordeaux, France.
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Pavia MJ, Finn D, Macedo-Tafur F, Tello-Espinoza R, Penaccio C, Bouskill N, Cadillo-Quiroz H. Genes and genome-resolved metagenomics reveal the microbial functional make up of Amazon peatlands under geochemical gradients. Environ Microbiol 2023; 25:2388-2403. [PMID: 37501535 DOI: 10.1111/1462-2920.16469] [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: 12/20/2022] [Accepted: 07/12/2023] [Indexed: 07/29/2023]
Abstract
The Pastaza-Marañón Foreland Basin (PMFB) holds the most extensive tropical peatland area in South America. PMFB peatlands store ~7.07 Gt of organic carbon interacting with multiple microbial heterotrophic, methanogenic, and other aerobic/anaerobic respirations. Little is understood about the contribution of distinct microbial community members inhabiting tropical peatlands. Here, we studied the metagenomes of three geochemically distinct peatlands spanning minerotrophic, mixed, and ombrotrophic conditions. Using gene- and genome-centric approaches, we evaluate the functional potential of the underlying microbial communities. Abundance analyses show significant differences in C, N, P, and S acquisition genes. Furthermore, community interactions mediated by toxin-antitoxin and CRISPR-Cas systems were enriched in oligotrophic soils, suggesting that non-metabolic interactions may exert additional controls in low-nutrient environments. Additionally, we reconstructed 519 metagenome-assembled genomes spanning 28 phyla. Our analyses detail key differences across the geochemical gradient in the predicted microbial populations involved in degradation of organic matter, and the cycling of N and S. Notably, we observed differences in the nitric oxide (NO) reduction strategies between sites with high and low N2 O fluxes and found phyla putatively capable of both NO and sulfate reduction. Our findings detail how gene abundances and microbial populations are influenced by geochemical differences in tropical peatlands.
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Affiliation(s)
- Michael J Pavia
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
- Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Damien Finn
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Franco Macedo-Tafur
- Laboratory of Soil Research, Research Institute of Amazonia's Natural Resources, National University of the Peruvian Amazon, Iquitos, Loreto, Peru
| | - Rodil Tello-Espinoza
- Laboratory of Soil Research, Research Institute of Amazonia's Natural Resources, National University of the Peruvian Amazon, Iquitos, Loreto, Peru
- School of Forestry, National University of the Peruvian Amazon, Iquitos, Loreto, Peru
| | - Christa Penaccio
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Nicholas Bouskill
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Hinsby Cadillo-Quiroz
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
- Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
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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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Wang Y, Chen Z, Zhao F, Yang H. Metabolome shifts triggered by chlorine sanitisation induce Escherichia coli on fresh produce into the viable but nonculturable state. Food Res Int 2023; 171:113084. [PMID: 37330837 DOI: 10.1016/j.foodres.2023.113084] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/30/2023] [Accepted: 06/01/2023] [Indexed: 06/19/2023]
Abstract
Facing the increasing occurrence of "big six" Escherichia coli outbreaks linked to fresh produce, chlorine-based sanitisers are widely used for fresh produce decontamination in recent years. However, latest finding that chlorine may induce E. coli cells into a viable not nonculturable (VBNC) state is bringing a new challenge to the fresh produce industry. VBNC cells are undetectable by the plate count test, and yet they retain pathogenicity and are more antibiotic-resistant than culturable cells. As a result, their eradication is critical to ensure the safety of fresh produce. Understanding VBNC cells at the metabolic level may provide a breakthrough for their eradication. Therefore, this study was carried out to collect the VBNC pathogenic E. coli (O26:H11, O121:H19, and O157:H7) cells from chlorine-treated pea sprouts and characterise them using NMR-based metabolomics. From the globally increased metabolite contents detected in the VBNC E. coli cells as compared to the culturable cells, mechanisms underlying E. coli's VBNC induction were elucidated. These include rendering the energy generation scheme to become more compatible with the lowered energy needs, disaggregating protein aggregates to release amino acids for osmoprotection and later resuscitation, as well as increasing cAMP content to downregulate RpoS. These identified metabolic characteristics can inspire future development of targeted measures for VBNC E. coli cell inhibition. Our methods can also be applied to other pathogens to help lower the risk of overall foodborne diseases.
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Affiliation(s)
- Yue Wang
- Department of Food Science and Technology, National University of Singapore, Singapore 117542, Singapore.
| | - Zihui Chen
- Department of Food Science and Technology, National University of Singapore, Singapore 117542, Singapore
| | - Fengnian Zhao
- Department of Food Science and Technology, National University of Singapore, Singapore 117542, Singapore
| | - Hongshun Yang
- Shaoxing Key Laboratory of Traditional Fermentation Food and Human Health, Jiangnan University (Shaoxing) Industrial Technology Research Institute, Zhejiang, 312000, China.
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Pagani TD, Corrêa PR, Lima C, Gomes LHF, Schwarz MGA, Galvão TC, Degrave WM, Valadares NF, Mendonça-Lima L. Impact of Genomic Deletion RD16 on the Expression of the Mycobacterium bovis BCG Moreau VapBC47 Toxin-Antitoxin System. Curr Issues Mol Biol 2023; 45:6538-6549. [PMID: 37623231 PMCID: PMC10453824 DOI: 10.3390/cimb45080412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 05/23/2023] [Accepted: 05/27/2023] [Indexed: 08/26/2023] Open
Abstract
Mycobacterium bovis BCG is the only vaccine against tuberculosis. The variable forms of cultivation throughout the years, before seed-lots were developed, allowed in vitro evolution of the original strain, generating a family of vaccines with different phenotypic and genotypic characteristics. Molecular studies revealed regions of difference (RDs) in the genomes of the various BCG strains. This work aims to characterize the gene pair rv3407-rv3408 (vapB47-vapC47), coding for a toxin-antitoxin system of the VapBC family, and to evaluate possible transcriptional effects due to the adjacent BCG Moreau-specific genomic deletion RD16. We show that these genes are co-transcribed in BCG strains Moreau and Pasteur, and that the inactivation of an upstream transcriptional repressor (Rv3405c) due to RD16 has a polar effect, leading to increased vapBC47 expression. Furthermore, we detect VapB47 DNA binding in vitro, dependent on a 5' vapB47 sequence that contributes to a palindrome, spanning the promoter and coding region. Our data shed light on the regulation of VapBC systems and on the impact of the BCG Moreau RD16 deletion in the expression of adjacent genes, contributing to a better understanding of BCG Moreau physiology.
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Affiliation(s)
- Talita Duarte Pagani
- Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro 21040-360, RJ, Brazil; (T.D.P.); (P.R.C.); (C.L.); (L.H.F.G.); (M.G.A.S.); (W.M.D.)
| | - Paloma Rezende Corrêa
- Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro 21040-360, RJ, Brazil; (T.D.P.); (P.R.C.); (C.L.); (L.H.F.G.); (M.G.A.S.); (W.M.D.)
| | - Cristiane Lima
- Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro 21040-360, RJ, Brazil; (T.D.P.); (P.R.C.); (C.L.); (L.H.F.G.); (M.G.A.S.); (W.M.D.)
| | - Leonardo Henrique Ferreira Gomes
- Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro 21040-360, RJ, Brazil; (T.D.P.); (P.R.C.); (C.L.); (L.H.F.G.); (M.G.A.S.); (W.M.D.)
| | - Marcos Gustavo Araujo Schwarz
- Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro 21040-360, RJ, Brazil; (T.D.P.); (P.R.C.); (C.L.); (L.H.F.G.); (M.G.A.S.); (W.M.D.)
| | - Teca Calcagno Galvão
- Laboratório de Bacteriologia, Centro de Referência Prof. Hélio Fraga, Escola Nacional de Saúde Pública Sergio Arouca, Fiocruz, Rio de Janeiro 21041-210, RJ, Brazil;
| | - Wim Maurits Degrave
- Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro 21040-360, RJ, Brazil; (T.D.P.); (P.R.C.); (C.L.); (L.H.F.G.); (M.G.A.S.); (W.M.D.)
| | | | - Leila Mendonça-Lima
- Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro 21040-360, RJ, Brazil; (T.D.P.); (P.R.C.); (C.L.); (L.H.F.G.); (M.G.A.S.); (W.M.D.)
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Song Y, Tang H, Bao R. Comparative analysis of five type II TA systems identified in Pseudomonas aeruginosa reveals their contributions to persistence and intracellular survival. Front Cell Infect Microbiol 2023; 13:1127786. [PMID: 36844395 PMCID: PMC9948252 DOI: 10.3389/fcimb.2023.1127786] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 02/01/2023] [Indexed: 02/11/2023] Open
Abstract
Background Pseudomonas aeruginosa is a grave nosocomial pathogen that persistently inhabits the lungs of patients with cystic fibrosis (CF) and causes various chronic infections. The bacterial toxin-antitoxin (TA) system is associated with latent and long-term infections, but the underlying mechanisms remain to be fully characterized. Methods We here investigated the diversity and function of five genomic type II TA systems widely distributed among P. aeruginosa clinical isolates. We also examined the distinct structural features of the toxin protein from different TA systems and characterized their contributions to persistence, invasion ability, and intracellular infection caused by P. aeruginosa. Results ParDE, PA1030/PA1029, and HigBA could modulate persister cell formation under treatment with specific antibiotics. Furthermore, cell-based transcriptional and invasion assays revealed that PA1030/PA1029 and HigBA TA systems were critical for intracellular survival. Discussion Our results highlight the prevalence and diverse roles of type II TA systems in P. aeruginosa and evaluate the possibility of using PA1030/PA1029 and HigBA TA pairs as targets for novel antibiotic treatments.
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Affiliation(s)
- Yingjie Song
- College of Life Science, Sichuan Normal University, Chengdu, China
| | - Hong Tang
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
- *Correspondence: Rui Bao, ; Hong Tang,
| | - Rui Bao
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
- *Correspondence: Rui Bao, ; Hong Tang,
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Chandra S, Gupta K, Khare S, Kohli P, Asok A, Mohan SV, Gowda H, Varadarajan R. The High Mutational Sensitivity of ccdA Antitoxin Is Linked to Codon Optimality. Mol Biol Evol 2022; 39:msac187. [PMID: 36069948 PMCID: PMC9555053 DOI: 10.1093/molbev/msac187] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Deep mutational scanning studies suggest that synonymous mutations are typically silent and that most exposed, nonactive-site residues are tolerant to mutations. Here, we show that the ccdA antitoxin component of the Escherichia coli ccdAB toxin-antitoxin system is unusually sensitive to mutations when studied in the operonic context. A large fraction (∼80%) of single-codon mutations, including many synonymous mutations in the ccdA gene shows inactive phenotype, but they retain native-like binding affinity towards cognate toxin, CcdB. Therefore, the observed phenotypic effects are largely not due to alterations in protein structure/stability, consistent with a large region of CcdA being intrinsically disordered. E. coli codon preference and strength of ribosome-binding associated with translation of downstream ccdB gene are found to be major contributors of the observed ccdA mutant phenotypes. In select cases, proteomics studies reveal altered ratios of CcdA:CcdB protein levels in vivo, suggesting that the ccdA mutations likely alter relative translation efficiencies of the two genes in the operon. We extend these results by studying single-site synonymous mutations that lead to loss of function phenotypes in the relBE operon upon introduction of rarer codons. Thus, in their operonic context, genes are likely to be more sensitive to both synonymous and nonsynonymous point mutations than inferred previously.
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Affiliation(s)
- Soumyanetra Chandra
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Kritika Gupta
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Shruti Khare
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Pehu Kohli
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Aparna Asok
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | | | - Harsha Gowda
- Institute of Bioinformatics, Bangalore 560100, India
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12
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Kessler DA, Levine H. Phenomenological Approach to Cancer Cell Persistence. PHYSICAL REVIEW LETTERS 2022; 129:108101. [PMID: 36112430 DOI: 10.1103/physrevlett.129.108101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 07/11/2022] [Indexed: 06/15/2023]
Abstract
Drug persistence is a phenomenon by which a small percentage of cancer cells survive the presentation of targeted therapy by transitioning to a quiescent state. Eventually some of these persister cells can transition back to an active growing state and give rise to resistant tumors. Here we introduce a quantitative genetics approach to drug-exposed populations of cancer cells in order to interpret recent experimental data regarding inheritance of persister probability. Our results indicate that alternating periods of drug treatment and drug removal may not be an effective strategy for eliminating persisters.
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Affiliation(s)
- David A Kessler
- Department of Physics, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Herbert Levine
- Center for Theoretical Biological Physics and Departments of Physics and Bioengineering, Northeastern University, Boston, Massachusetts 02215, USA
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13
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Berkvens A, Chauhan P, Bruggeman FJ. Integrative biology of persister cell formation: molecular circuitry, phenotypic diversification and fitness effects. JOURNAL OF THE ROYAL SOCIETY, INTERFACE 2022; 19:20220129. [PMID: 36099930 PMCID: PMC9470271 DOI: 10.1098/rsif.2022.0129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Microbial populations often contain persister cells, which reduce the extinction risk upon sudden stresses. Persister cell formation is deeply intertwined with physiology. Due to this complexity, it cannot be satisfactorily understood by focusing only on mechanistic, physiological or evolutionary aspects. In this review, we take an integrative biology perspective to identify common principles of persister cell formation, which might be applicable across evolutionary-distinct microbes. Persister cells probably evolved to cope with a fundamental trade-off between cellular stress and growth tasks, as any biosynthetic resource investment in growth-supporting proteins is at the expense of stress tasks and vice versa. Natural selection probably favours persister cell subpopulation formation over a single-phenotype strategy, where each cell is prepared for growth and stress to a suboptimal extent, since persister cells can withstand harsher environments and their coexistence with growing cells leads to a higher fitness. The formation of coexisting phenotypes requires bistable molecular circuitry. Bistability probably emerges from growth-modulated, positive feedback loops in the cell's growth versus stress control network, involving interactions between sigma factors, guanosine pentaphosphate and toxin-antitoxin (TA) systems. We conclude that persister cell formation is most likely a response to a sudden reduction in growth rate, which can be achieved by antibiotic addition, nutrient starvation, sudden stresses, nutrient transitions or activation of a TA system.
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Affiliation(s)
- Alicia Berkvens
- Systems Biology Lab, AIMMS, VU University, De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands
| | - Priyanka Chauhan
- Systems Biology Lab, AIMMS, VU University, De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands
| | - Frank J Bruggeman
- Systems Biology Lab, AIMMS, VU University, De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands
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14
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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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15
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Kermi C, Lau L, Asadi Shahmirzadi A, Classon M. Disrupting Mechanisms that Regulate Genomic Repeat Elements to Combat Cancer and Drug Resistance. Front Cell Dev Biol 2022; 10:826461. [PMID: 35602594 PMCID: PMC9114874 DOI: 10.3389/fcell.2022.826461] [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: 11/30/2021] [Accepted: 03/30/2022] [Indexed: 11/13/2022] Open
Abstract
Despite advancements in understanding cancer pathogenesis and the development of many effective therapeutic agents, resistance to drug treatment remains a widespread challenge that substantially limits curative outcomes. The historical focus on genetic evolution under drug “pressure” as a key driver of resistance has uncovered numerous mechanisms of therapeutic value, especially with respect to acquired resistance. However, recent discoveries have also revealed a potential role for an ancient evolutionary balance between endogenous “viral” elements in the human genome and diverse factors involved in their restriction in tumor evolution and drug resistance. It has long been appreciated that the stability of genomic repeats such as telomeres and centromeres affect tumor fitness, but recent findings suggest that de-regulation of other repetitive genome elements, including retrotransposons, might also be exploited as cancer therapy. This review aims to present an overview of these recent findings.
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16
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Carvalho IGB, Merfa MV, Teixeira-Silva NS, Martins PMM, Takita MA, de Souza AA. Overexpression of mqsR in Xylella fastidiosa Leads to a Priming Effect of Cells to Copper Stress Tolerance. Front Microbiol 2021; 12:712564. [PMID: 34616378 PMCID: PMC8488296 DOI: 10.3389/fmicb.2021.712564] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 08/09/2021] [Indexed: 12/13/2022] Open
Abstract
Copper-based compounds are widely used in agriculture as a chemical strategy to limit the spread of multiple plant diseases; however, the continuous use of this heavy metal has caused environmental damage as well as the development of copper-resistant strains. Thus, it is important to understand how the bacterial phytopathogens evolve to manage with this metal in the field. The MqsRA Toxin-Antitoxin system has been recently described for its function in biofilm formation and copper tolerance in Xylella fastidiosa, a plant-pathogen bacterium responsible for economic damage in several crops worldwide. Here we identified differentially regulated genes by X. fastidiosa MqsRA by assessing changes in global gene expression with and without copper. Results show that mqsR overexpression led to changes in the pattern of cell aggregation, culminating in a global phenotypic heterogeneity, indicative of persister cell formation. This phenotype was also observed in wild-type cells but only in the presence of copper. This suggests that MqsR regulates genes that alter cell behavior in order to prime them to respond to copper stress, which is supported by RNA-Seq analysis. To increase cellular tolerance, proteolysis and efflux pumps and regulator related to multidrug resistance are induced in the presence of copper, in an MqsR-independent response. In this study we show a network of genes modulated by MqsR that is associated with induction of persistence in X. fastidiosa. Persistence in plant-pathogenic bacteria is an important genetic tolerance mechanism still neglected for management of phytopathogens in agriculture, for which this work expands the current knowledge and opens new perspectives for studies aiming for a more efficient control in the field.
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Affiliation(s)
| | - Marcus Vinicius Merfa
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States
| | | | | | - Marco Aurélio Takita
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico, Cordeirópolis, Brazil
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A minimal model for gene expression dynamics of bacterial type II toxin-antitoxin systems. Sci Rep 2021; 11:19516. [PMID: 34593858 PMCID: PMC8484670 DOI: 10.1038/s41598-021-98570-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 09/07/2021] [Indexed: 02/08/2023] Open
Abstract
Toxin-antitoxin (TA) modules are part of most bacteria's regulatory machinery for stress responses and general aspects of their physiology. Due to the interplay of a long-lived toxin with a short-lived antitoxin, TA modules have also become systems of interest for mathematical modelling. Here we resort to previous modelling efforts and extract from these a minimal model of type II TA system dynamics on a timescale of hours, which can be used to describe time courses derived from gene expression data of TA pairs. We show that this model provides a good quantitative description of TA dynamics for the 11 TA pairs under investigation here, while simpler models do not. Our study brings together aspects of Biophysics with its focus on mathematical modelling and Computational Systems Biology with its focus on the quantitative interpretation of 'omics' data. This mechanistic model serves as a generic transformation of time course information into kinetic parameters. The resulting parameter vector can, in turn, be mechanistically interpreted. We expect that TA pairs with similar mechanisms are characterized by similar vectors of kinetic parameters, allowing us to hypothesize on the mode of action for TA pairs still under discussion.
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18
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Qi X, Brothers KM, Ma D, Mandell JB, Donegan NP, Cheung AL, Richardson AR, Urish KL. The Staphylococcus aureus toxin-antitoxin system YefM-YoeB is associated with antibiotic tolerance and extracellular dependent biofilm formation. J Bone Jt Infect 2021; 6:241-253. [PMID: 34262845 PMCID: PMC8273624 DOI: 10.5194/jbji-6-241-2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 05/26/2021] [Indexed: 11/20/2022] Open
Abstract
The high antibiotic tolerance of Staphylococcus aureus biofilms is associated with challenges
for treating periprosthetic joint infection. The toxin–antitoxin system,
YefM–YoeB, is thought to be a regulator for antibiotic tolerance, but its
physiological role is unknown. The objective of this study was to determine
the biofilm and antibiotic susceptibility phenotypes associated with S. aureus yoeB
homologs. We hypothesized the toxin–antitoxin yoeB homologs contribute to
biofilm formation and antibiotic susceptibility. Disruption of yoeB1 and
yoeB2 resulted in decreased biofilm formation in comparison to Newman and JE2
wild-type (WT) S. aureus strains. In comparison to yoeB mutants, both Newman and JE2 WT
strains had higher polysaccharide intercellular adhesin (PIA) production.
Treatment with sodium metaperiodate increased biofilm formation in Newman
WT, indicating biofilm formation may be increased under conditions of
oxidative stress. DNase I treatment decreased biofilm formation in Newman
WT but not in the absence of yoeB1 or yoeB2. Additionally, WT strains had a higher
extracellular DNA (eDNA) content in comparison to yoeB mutants but no
differences in biofilm protein content. Moreover, loss of yoeB1 and yoeB2 decreased
biofilm survival in both Newman and JE2 strains. Finally, in a neutropenic
mouse abscess model, deletion of yoeB1 and yoeB2 resulted in reduced bacterial
burden. In conclusion, our data suggest that yoeB1 and yoeB2 are associated with
S. aureus planktonic growth, extracellular dependent biofilm formation, antibiotic
tolerance, and virulence.
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Affiliation(s)
- Xinyu Qi
- Arthritis and Arthroplasty Design Group (AAD Lab), Department of Orthopaedic Surgery, College of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Orthopedic Surgery, the First Affiliated Hospital of Traditional Chinese Medicine of Guangzhou University, Guangzhou, Guangdong, China
| | - Kimberly M Brothers
- Arthritis and Arthroplasty Design Group (AAD Lab), Department of Orthopaedic Surgery, College of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Dongzhu Ma
- Arthritis and Arthroplasty Design Group (AAD Lab), Department of Orthopaedic Surgery, College of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jonathan B Mandell
- Arthritis and Arthroplasty Design Group (AAD Lab), Department of Orthopaedic Surgery, College of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Niles P Donegan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, New Hampshire, USA
| | - Ambrose L Cheung
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, New Hampshire, USA
| | - Anthony R Richardson
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Kenneth L Urish
- Arthritis and Arthroplasty Design Group (AAD Lab), Department of Orthopaedic Surgery, College of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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19
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Xia K, Ma J, Liang X. Impacts of type II toxin-antitoxin systems on cell physiology and environmental behavior in acetic acid bacteria. Appl Microbiol Biotechnol 2021; 105:4357-4367. [PMID: 34021811 DOI: 10.1007/s00253-021-11357-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 05/08/2021] [Accepted: 05/16/2021] [Indexed: 12/19/2022]
Abstract
Acetic acid bacteria (AAB) are a group of Gram-negative and strictly aerobic microorganisms widely used in vinegar industry, especially the species belonging to the genera Acetobacter and Komagataeibacter. The environments inhabited by AAB during the vinegar fermentation, in particular those natural traditional bioprocesses, are complex and dynamically changed, usually accompanied by diverse microorganisms, bacteriophages, and the increasing acetic acid concentration. For this reason, how AAB survive to such harsh niches has always been an interesting research field. Previous omic analyses (e.g., genomics, proteomics, and transcriptomics) have provided abundant clues for the metabolic pathways and bioprocesses indispensable for the acid stress adaptation of AAB. Nevertheless, it is far from fully understanding what factors regulate these modular mechanisms overtly and covertly upon shifting environments. Bacterial toxin-antitoxin systems (TAS), usually consisting of a pair of genes encoding a stable toxin and an unstable antitoxin that is capable of counteracting the toxin, have been uncovered to have a variety of biological functions. Recent studies focusing on the role of TAS in Acetobacter pasteurianus suggest that TAS contribute substantially to the acid stress resistance. In this mini review, we discuss the biological functions of type II TAS in the context of AAB with regard to the acid stress resistance, persister formation and resuscitation, genome stability, and phage immunity. KEY POINTS: • Type II TAS act as regulators in the acid stress resistance of AAB. • Type II TAS are implicated in the formation of acid-tolerant persister cells in AAB. • Type II TAS are potential factors responsible for phage immunity and genome stability.
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Affiliation(s)
- Kai Xia
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Jiawen Ma
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China.,Institute of Food Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Xinle Liang
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China. .,Institute of Food Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China.
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20
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Zlotnicki J, Gabrielli A, Urish KL, Brothers KM. Clinical Evidence of Current Irrigation Practices and the Use of Oral Antibiotics to Prevent and Treat Periprosthetic Joint Infection. Orthop Clin North Am 2021; 52:93-101. [PMID: 33752842 PMCID: PMC7990073 DOI: 10.1016/j.ocl.2020.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Jason Zlotnicki
- Arthritis and Arthroplasty Design Group, Department of Orthopaedic Surgery, College of Medicine, University of Pittsburgh, Bridgeside Point II, 450 Technology Drive, Pittsburgh, PA 15219, USA
| | - Alexandra Gabrielli
- Arthritis and Arthroplasty Design Group, Department of Orthopaedic Surgery, College of Medicine, University of Pittsburgh, Bridgeside Point II, 450 Technology Drive, Pittsburgh, PA 15219, USA
| | - Kenneth L Urish
- Arthritis and Arthroplasty Design Group, Department of Orthopaedic Surgery, College of Medicine, University of Pittsburgh, Bridgeside Point II, 450 Technology Drive, Pittsburgh, PA 15219, USA
| | - Kimberly M Brothers
- Arthritis and Arthroplasty Design Group, Department of Orthopaedic Surgery, College of Medicine, University of Pittsburgh, Bridgeside Point II, 450 Technology Drive, Pittsburgh, PA 15219, USA.
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Evaluation of Putative Type II Toxin-Antitoxin Systems and Lon Protease Expression in Shigella flexneri Following Infection of Caco-2 Cells. ARCHIVES OF CLINICAL INFECTIOUS DISEASES 2020. [DOI: 10.5812/archcid.98625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
: Shigella flexneri causes bacillary dysentery in developing countries. Due to recent reports regarding antimicrobial resistance in human S. flexneri, finding alternative therapeutics is of vital importance. Toxin-antitoxin (TA) systems have recently been introduced as antimicrobial targets owing to their involvement in bacterial survival in stress conditions and “persister” cell formation. In this study, the presence of four TA loci were studied in S. flexneri ATCC 12022. The presence of genes coding for the identified TA loci and Lon protease were confirmed by the PCR method using specific primers. Caco-2 cell lines were then infected with this standard strain, and 8 and 24 h post-infection, expression levels of genes coding for the studied TA loci, and Lon protease were evaluated using a real-time PCR method. Expression of mazF, GNAT (Gcn5-related N-acetyltransferase), yeeU, pfam13975, and Lon genes showed 5.4, 9.8, 2.3, 2.7, and 13.8-fold increase, respectively, 8 h after bacterial invasion of the Caco-2 cell line. In addition, the expression of the aforementioned genes showed 4.8, 10.8, 2.3, 3.7, and 16.8-fold increase after 24 h. The GNAT and lon genes showed significantly higher expression levels compared to the control (P value < 0.05). However, the increase in the expression level of yeeU was the same at 8 h and 24 h post-infection. In addition, mazF expression level showed a slight decrease at 24 h compared to 8h post-infection. Genes coding for GNAT and Lon protease showed a significantly higher expression after invading the Caco-2 cell line. Therefore, targeting GNAT or Lon protease can be taken into consideration for finding novel antimicrobial drug strategies. The exact functions and mechanisms of TA systems in S. flexneri isolates are suggested to be experimentally determined.
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Valderrama-Gómez MÁ, Lomnitz JG, Fasani RA, Savageau MA. Mechanistic Modeling of Biochemical Systems without A Priori Parameter Values Using the Design Space Toolbox v.3.0. iScience 2020; 23:101200. [PMID: 32531747 PMCID: PMC7287267 DOI: 10.1016/j.isci.2020.101200] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 05/04/2020] [Accepted: 05/21/2020] [Indexed: 01/24/2023] Open
Abstract
Mechanistic models of biochemical systems provide a rigorous description of biological phenomena. They are indispensable for making predictions and elucidating biological design principles. To date, mathematical analysis and characterization of these models encounter a bottleneck consisting of large numbers of unknown parameter values. Here, we introduce the Design Space Toolbox v.3.0 (DST3), a software implementation of the Design Space formalism enabling mechanistic modeling without requiring previous knowledge of parameter values. This is achieved by using a phenotype-centric modeling approach, in which the system is first decomposed into a series of biochemical phenotypes. Parameter values realizing phenotypes of interest are subsequently predicted. DST3 represents the most generally applicable implementation of the Design Space formalism and offers unique advantages over earlier versions. By expanding the Design Space formalism and streamlining its distribution, DST3 represents a valuable tool for elucidating biological design principles and designing novel synthetic circuits. DST3 extends the Design Space formalism by identifying additional phenotypes Additional phenotypes arise from cycles, conservations, and metabolic imbalances DST3 enables mechanistic modeling without previous knowledge of parameter values It fully unlocks the potential of the novel phenotype-centric modeling strategy
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Affiliation(s)
| | | | | | - Michael A Savageau
- Department of Microbiology & Molecular Genetics, University of California, Davis, CA 95616, USA; Department of Biomedical Engineering, University of California, Davis, CA 95616, USA.
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Ramisetty BCM. Regulation of Type II Toxin-Antitoxin Systems: The Translation-Responsive Model. Front Microbiol 2020; 11:895. [PMID: 32431690 PMCID: PMC7214741 DOI: 10.3389/fmicb.2020.00895] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 04/16/2020] [Indexed: 12/19/2022] Open
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Role of antibiotic stress in phenotypic switching to persister cells of antibiotic-resistant Staphylococcus aureus. ANN MICROBIOL 2020. [DOI: 10.1186/s13213-020-01552-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Abstract
Purpose
This study was designed to evaluate phenotypic and genotypic properties of persister cells formed by Staphylococcus aureus ATCC 15564 (SAWT), oxacillin-induced S. aureus (SAOXA), ciprofloxacin-induced S. aureus (SACIP), and clinically isolated multidrug-resistant S. aureus CCARM 3080 (SAMDR).
Methods
The dose-dependent biphasic killing patterns were observed for SAWT, SAOXA, SACIP, and SAMDR in response to twofold minimum inhibitory concentrate (MIC) of ciprofloxacin. The surviving cells of SAWT, SAOXA, SACIP, and SAMDR after twofold MIC of ciprofloxacin treatment were analyzed using a metabolic-based assay to estimate the fractions of persister cells.
Results
The least persister formation was induced in SACIP after twofold MIC of ciprofloxacin treatment, showing 58% of persistence. The lowest fitness cost of resistance was observed for the recovered persister cells of SACIP (relative fitness = 0.95), followed by SAMDR (relative fitness = 0.70), while the highest fitness cost was observed for SAWT (relative fitness = 0.26). The mRNA transcripts were analyzed by RT-PCR assay in recovered persister cells pre-incubated with ciprofloxacin. The highest expression levels of stress-related genes (dnaK and groEL) and efflux pump-related genes (mepR, norA, and norB) were observed in the recovered persister cells of SAOXA and SAMDR.
Conclusion
This study provides valuable information for understanding crosstalk between antibiotic resistance, tolerance, and persistence in different antibiotic-resistant S. aureus strains.
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Deciphering the Antitoxin-Regulated Bacterial Stress Response via Single-Cell Analysis. ACS Chem Biol 2019; 14:2859-2866. [PMID: 31670944 DOI: 10.1021/acschembio.9b00721] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Bacterial toxin-antitoxin (TA) systems, which are diverse and widespread among prokaryotes, are responsible for tolerance to drugs and environmental stresses. However, the low abundance of toxin and antitoxin proteins renders their quantitative measurement in single bacteria challenging. Employing a laboratory-built nano-flow cytometer (nFCM) to monitor a tetracysteine (TC)-tagged TA system labeled with the biarsenical dye FlAsH, we here report the development of a sensitive method that enables the detection of basal-level expression of antitoxin. Using the Escherichia coli MqsR/MqsA as a model TA system, we reveal for the first time that under its native promoter and in the absence of environmental stress, there exist two populations of bacteria with high or low levels of antitoxin MqsA. Under environmental stress, such as bile acid stress, heat shock, and amino acid starvation, the two populations of bacteria responded differently in terms of MqsA degradation and production. Subsequently, resumed production of MqsA after amino acid stress was observed for the first time. Taking advantage of the multiparameter capability of nFCM, bacterial growth rate and MqsA production were analyzed simultaneously. We found that under environmental stress, the response of bacterial growth was consistent with MqsA production but with an approximate 60 min lag. Overall, the results of the present study indicate that stochastic elevation of MqsA level facilitates bacterial survival, and the two populations with distinct phenotypes empower bacteria to deal with fluctuating environments. This analytical method will help researchers gain deeper insight into the heterogeneity and fundamental role of TA systems.
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Zamakhaev MV, Goncharenko AV, Shumkov MS. Toxin-Antitoxin Systems and Bacterial Persistence (Review). APPL BIOCHEM MICRO+ 2019. [DOI: 10.1134/s0003683819060140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Carvalho G, Forestier C, Mathias JD. Antibiotic resilience: a necessary concept to complement antibiotic resistance? Proc Biol Sci 2019; 286:20192408. [PMID: 31795866 DOI: 10.1098/rspb.2019.2408] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Resilience is the capacity of systems to recover their initial state or functions after a disturbance. The concepts of resilience and resistance are complementary in ecology and both represent different aspects of the stability of ecosystems. However, antibiotic resilience is not used in clinical bacteriology whereas antibiotic resistance is a recognized major problem. To join the fields of ecology and clinical bacteriology, we first review the resilience concept from ecology, socio-ecological systems and microbiology where it is widely developed. We then review resilience-related concepts in microbiology, including bacterial tolerance and persistence, phenotypic heterogeneity and collective tolerance and resistance. We discuss how antibiotic resilience could be defined and argue that the use of this concept largely relies on its experimental measure and its clinical relevance. We review indicators in microbiology which could be used to reflect antibiotic resilience and used as valuable indicators to anticipate the capacity of bacteria to recover from antibiotic treatments.
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Affiliation(s)
- Gabriel Carvalho
- Université Clermont Auvergne, Irstea, UR LISC, Centre de Clermont-Ferrand, 9 Avenue Blaise Pascal CS 20085, F-63178, Aubière, France
| | | | - Jean-Denis Mathias
- Université Clermont Auvergne, Irstea, UR LISC, Centre de Clermont-Ferrand, 9 Avenue Blaise Pascal CS 20085, F-63178, Aubière, France
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28
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Khlebodarova TM, Likhoshvai VA. Molecular Mechanisms of Non-Inherited Antibiotic Tolerance in Bacteria and Archaea. Mol Biol 2019. [DOI: 10.1134/s0026893319040058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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29
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Kushwaha GS, Oyeyemi BF, Bhavesh NS. Stringent response protein as a potential target to intervene persistent bacterial infection. Biochimie 2019; 165:67-75. [PMID: 31302165 DOI: 10.1016/j.biochi.2019.07.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 07/07/2019] [Indexed: 01/25/2023]
Abstract
More than half of the world's population is infected with persistent bacterial infections, consequently, persisters are gradually becoming a major public health concern. During the persistent phase, bacterial pathogens deploy many regulatory strategies to compensate unfavorable host environmental conditions. The stringent response is one of such gene regulatory mechanisms which is stimulated by nutrient starvation. It is regulated by the synthesis of highly phosphorylated signaling nucleotides, (p)ppGpp or alarmone. (p)ppGpp is synthesized by ppGpp synthetases, and these proteins are classified as RelA/SpoT homolog (RSH) proteins. Subsequently, (p)ppGpp modulate several molecular and biochemical processes ranging from transcription to metabolism. Imperativeness of (p)ppGpp synthetases has been investigated by numerous approaches including microbiology and animal studies, thereby establishing that Rel enzyme deleted strains of pathogenic bacteria were unable to transform in persister form. In this review, we summarize recent findings to corroborate the rationality to consider (p)ppGpp synthetase as a potential target in discovering a novel class of antimicrobial agents to combat persistent infections. Moreover, inhibition studies on Mycobacterium tuberculosis (p)ppGpp synthetase shows that these inhibitors prevent dormant state transition and biofilm formation. Also, we have highlighted the structural biology of (p)ppGpp synthetases, which may provide significant information that could be used in structure-based inhibitor design.
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Affiliation(s)
- Gajraj Singh Kushwaha
- Transcription Regulation Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067, India.
| | - Bolaji Fatai Oyeyemi
- Transcription Regulation Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Neel Sarovar Bhavesh
- Transcription Regulation Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067, India.
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Ferrari A, Maggi S, Montanini B, Levante A, Lazzi C, Yamaguchi Y, Rivetti C, Folli C. Identification and first characterization of DinJ-YafQ toxin-antitoxin systems in Lactobacillus species of biotechnological interest. Sci Rep 2019; 9:7645. [PMID: 31114007 PMCID: PMC6529426 DOI: 10.1038/s41598-019-44094-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 05/09/2019] [Indexed: 11/18/2022] Open
Abstract
DinJ-YafQ is a type II TA system comprising the ribosome-dependent RNase YafQ toxin and the DinJ antitoxin protein. Although the module has been extensively characterized in Escherichia coli, little information is available for homologous systems in lactic acid bacteria. In this study, we employed bioinformatics tools to identify DinJ-YafQ systems in Lactobacillus casei, Lactobacillus paracasei and Lactobacillus rhamnosus species, commonly used in biotechnological processes. Among a total of nineteen systems found, two TA modules from Lactobacillus paracasei and two modules from Lactobacillus rhamnosus wild strains were isolated and their activity was verified by growth assays in Escherichia coli either in liquid and solid media. The RNase activity of the YafQ toxins was verified in vivo by probing mRNA dynamics and metabolism with single-cell Thioflavin T fluorescence. Our findings demonstrate that, albeit DinJ-YafQ TA systems are widely distributed in lactic acid bacteria, only few are fully functional, while others have lost toxicity even though they maintain high sequence identity with wild type YafQ and a likely functional antitoxin protein.
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Affiliation(s)
- Alberto Ferrari
- Department of Food and Drug, University of Parma, 43124, Parma, Italy
| | - Stefano Maggi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124, Parma, Italy
| | - Barbara Montanini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124, Parma, Italy
| | - Alessia Levante
- Department of Food and Drug, University of Parma, 43124, Parma, Italy
| | - Camilla Lazzi
- Department of Food and Drug, University of Parma, 43124, Parma, Italy
| | - Yoshihiro Yamaguchi
- The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Sumiyoshi-ku, 558-8585, Osaka, Japan
| | - Claudio Rivetti
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124, Parma, Italy.
| | - Claudia Folli
- Department of Food and Drug, University of Parma, 43124, Parma, Italy.
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Mandal S, Njikan S, Kumar A, Early JV, Parish T. The relevance of persisters in tuberculosis drug discovery. MICROBIOLOGY-SGM 2019; 165:492-499. [PMID: 30775961 DOI: 10.1099/mic.0.000760] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Bacterial persisters are a subpopulation of cells that exhibit phenotypic resistance during exposure to a lethal dose of antibiotics. They are difficult to target and thought to contribute to the long treatment duration required for tuberculosis. Understanding the molecular and cellular biology of persisters is critical to finding new tuberculosis drugs that shorten treatment. This review focuses on mycobacterial persisters and describes the challenges they pose in tuberculosis therapy, their characteristics and formation, how persistence leads to resistance, and the current approaches being used to target persisters within mycobacterial drug discovery.
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Affiliation(s)
- Soma Mandal
- TB Discovery Research, Infectious Disease Research Institute, 1616 Eastlake Ave. E, Suite 400, Seattle, WA 98102, USA
| | - Samuel Njikan
- TB Discovery Research, Infectious Disease Research Institute, 1616 Eastlake Ave. E, Suite 400, Seattle, WA 98102, USA
| | - Anuradha Kumar
- TB Discovery Research, Infectious Disease Research Institute, 1616 Eastlake Ave. E, Suite 400, Seattle, WA 98102, USA
| | - Julie V Early
- TB Discovery Research, Infectious Disease Research Institute, 1616 Eastlake Ave. E, Suite 400, Seattle, WA 98102, USA
| | - Tanya Parish
- TB Discovery Research, Infectious Disease Research Institute, 1616 Eastlake Ave. E, Suite 400, Seattle, WA 98102, USA
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A Systematic Overview of Type II and III Toxin-Antitoxin Systems with a Focus on Druggability. Toxins (Basel) 2018; 10:toxins10120515. [PMID: 30518070 PMCID: PMC6315513 DOI: 10.3390/toxins10120515] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 11/29/2018] [Accepted: 11/30/2018] [Indexed: 02/07/2023] Open
Abstract
Toxin-antitoxin (TA) systems are known to play various roles in physiological processes, such as gene regulation, growth arrest and survival, in bacteria exposed to environmental stress. Type II TA systems comprise natural complexes consisting of protein toxins and antitoxins. Each toxin and antitoxin participates in distinct regulatory mechanisms depending on the type of TA system. Recently, peptides designed by mimicking the interfaces between TA complexes showed its potential to activate the activity of toxin by competing its binding counterparts. Type II TA systems occur more often in pathogenic bacteria than in their nonpathogenic kin. Therefore, they can be possible drug targets, because of their high abundance in some pathogenic bacteria, such as Mycobacterium tuberculosis. In addition, recent bioinformatic analyses have shown that type III TA systems are highly abundant in the intestinal microbiota, and recent clinical studies have shown that the intestinal microbiota is linked to inflammatory diseases, obesity and even several types of cancer. We therefore focused on exploring the putative relationship between intestinal microbiota-related human diseases and type III TA systems. In this paper, we review and discuss the development of possible druggable materials based on the mechanism of type II and type III TA system.
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Valderrama-Gómez MA, Parales RE, Savageau MA. Phenotype-centric modeling for elucidation of biological design principles. J Theor Biol 2018; 455:281-292. [DOI: 10.1016/j.jtbi.2018.07.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 07/09/2018] [Indexed: 01/01/2023]
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Khlebodarova TM, Likhoshvai VA. Persister Cells - a Plausible Outcome of Neutral Coevolutionary Drift. Sci Rep 2018; 8:14309. [PMID: 30254316 PMCID: PMC6156226 DOI: 10.1038/s41598-018-32637-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 09/12/2018] [Indexed: 12/31/2022] Open
Abstract
The phenomenon of bacterial persistence - a non-inherited antibiotic tolerance in a minute fraction of the bacterial population, was observed more than 70 years ago. Nowadays, it is suggested that "persister cells" undergo an alternative scenario of the cell cycle; however, pathways involved in its emergence are still not identified. We present a mathematically grounded scenario of such possibility. We have determined that population drift in the space of multiple neutrally coupled mutations, which we called "neutrally coupled co-evolution" (NCCE), leads to increased dynamic complexity of bacterial populations via appearance of cells capable of carrying out a single cell cycle in two or more alternative ways and that universal properties of the coupled transcription-translation system underlie this phenotypic multiplicity. According to our hypothesis, modern persister cells have derived from such cells and regulatory mechanisms that govern the consolidation of this phenomenon represented the trigger. We assume that the described type of neutrally coupled co-evolution could play an important role in the origin of extremophiles, both in bacteria and archaea.
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Affiliation(s)
- T M Khlebodarova
- Department of Systems Biology, Institute of Cytology and Genetics, Russian Academy of Sciences, Siberian Branch, Novosibirsk, Russia.
| | - V A Likhoshvai
- Department of Systems Biology, Institute of Cytology and Genetics, Russian Academy of Sciences, Siberian Branch, Novosibirsk, Russia
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35
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Abstract
The ability of bacterial cells to adjust their gene expression program in response to environmental perturbation is often critical for their survival. Recent experimental advances allowing us to quantitatively record gene expression dynamics in single cells and in populations coupled with mathematical modeling enable mechanistic understanding on how these responses are shaped by the underlying regulatory networks. Here, we review how the combination of local and global factors affect dynamical responses of gene regulatory networks. Our goal is to discuss the general principles that allow extrapolation from a few model bacteria to less understood microbes. We emphasize that, in addition to well-studied effects of network architecture, network dynamics are shaped by global pleiotropic effects and cell physiology.
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Affiliation(s)
- David L Shis
- Department of Biosciences, Rice University, Houston, Texas 77005, USA;
| | - Matthew R Bennett
- Department of Biosciences, Rice University, Houston, Texas 77005, USA; .,Department of Bioengineering, Rice University, Houston, Texas 77005, USA
| | - Oleg A Igoshin
- Department of Biosciences, Rice University, Houston, Texas 77005, USA; .,Department of Bioengineering, Rice University, Houston, Texas 77005, USA.,Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, USA
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36
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Jolly MK, Kulkarni P, Weninger K, Orban J, Levine H. Phenotypic Plasticity, Bet-Hedging, and Androgen Independence in Prostate Cancer: Role of Non-Genetic Heterogeneity. Front Oncol 2018; 8:50. [PMID: 29560343 PMCID: PMC5845637 DOI: 10.3389/fonc.2018.00050] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Accepted: 02/19/2018] [Indexed: 12/21/2022] Open
Abstract
It is well known that genetic mutations can drive drug resistance and lead to tumor relapse. Here, we focus on alternate mechanisms-those without mutations, such as phenotypic plasticity and stochastic cell-to-cell variability that can also evade drug attacks by giving rise to drug-tolerant persisters. The phenomenon of persistence has been well-studied in bacteria and has also recently garnered attention in cancer. We draw a parallel between bacterial persistence and resistance against androgen deprivation therapy in prostate cancer (PCa), the primary standard care for metastatic disease. We illustrate how phenotypic plasticity and consequent mutation-independent or non-genetic heterogeneity possibly driven by protein conformational dynamics can stochastically give rise to androgen independence in PCa, and suggest that dynamic phenotypic plasticity should be considered in devising therapeutic dosing strategies designed to treat and manage PCa.
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Affiliation(s)
- Mohit Kumar Jolly
- Center for Theoretical Biological Physics, Rice University, Houston, TX, United States
| | - Prakash Kulkarni
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, United States
| | - Keith Weninger
- Department of Physics, North Carolina State University, Raleigh, NC, United States
| | - John Orban
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, United States
- Department of Chemistry and Biochemistry, University of Maryland, College Park, College Park, United States
| | - Herbert Levine
- Center for Theoretical Biological Physics, Rice University, Houston, TX, United States
- Department of Bioengineering, Rice University, Houston, TX, United States
- Department of Physics and Astronomy, Rice University, Houston, TX, United States
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37
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Bertaux F, Marguerat S, Shahrezaei V. Division rate, cell size and proteome allocation: impact on gene expression noise and implications for the dynamics of genetic circuits. ROYAL SOCIETY OPEN SCIENCE 2018; 5:172234. [PMID: 29657814 PMCID: PMC5882738 DOI: 10.1098/rsos.172234] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 02/15/2018] [Indexed: 05/12/2023]
Abstract
The cell division rate, size and gene expression programmes change in response to external conditions. These global changes impact on average concentrations of biomolecule and their variability or noise. Gene expression is inherently stochastic, and noise levels of individual proteins depend on synthesis and degradation rates as well as on cell-cycle dynamics. We have modelled stochastic gene expression inside growing and dividing cells to study the effect of division rates on noise in mRNA and protein expression. We use assumptions and parameters relevant to Escherichia coli, for which abundant quantitative data are available. We find that coupling of transcription, but not translation rates to the rate of cell division can result in protein concentration and noise homeostasis across conditions. Interestingly, we find that the increased cell size at fast division rates, observed in E. coli and other unicellular organisms, buffers noise levels even for proteins with decreased expression at faster growth. We then investigate the functional importance of these regulations using gene regulatory networks that exhibit bi-stability and oscillations. We find that network topology affects robustness to changes in division rate in complex and unexpected ways. In particular, a simple model of persistence, based on global physiological feedback, predicts increased proportion of persister cells at slow division rates. Altogether, our study reveals how cell size regulation in response to cell division rate could help controlling gene expression noise. It also highlights that understanding circuits' robustness across growth conditions is key for the effective design of synthetic biological systems.
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Affiliation(s)
- François Bertaux
- Department of Mathematics, Imperial College London, London SW7 2AZ,UK
- MRC London Institute of Medical Sciences (LMS), London W12 0NN, UK
- Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, UK
| | - Samuel Marguerat
- MRC London Institute of Medical Sciences (LMS), London W12 0NN, UK
- Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, UK
- Authors for correspondence: Samuel Marguerat e-mail:
| | - Vahid Shahrezaei
- Department of Mathematics, Imperial College London, London SW7 2AZ,UK
- Authors for correspondence: Vahid Shahrezaei e-mail:
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38
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Bertaux F, Marguerat S, Shahrezaei V. Division rate, cell size and proteome allocation: impact on gene expression noise and implications for the dynamics of genetic circuits. ROYAL SOCIETY OPEN SCIENCE 2018; 5:172234. [PMID: 29657814 DOI: 10.1101/209593] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 02/15/2018] [Indexed: 05/25/2023]
Abstract
The cell division rate, size and gene expression programmes change in response to external conditions. These global changes impact on average concentrations of biomolecule and their variability or noise. Gene expression is inherently stochastic, and noise levels of individual proteins depend on synthesis and degradation rates as well as on cell-cycle dynamics. We have modelled stochastic gene expression inside growing and dividing cells to study the effect of division rates on noise in mRNA and protein expression. We use assumptions and parameters relevant to Escherichia coli, for which abundant quantitative data are available. We find that coupling of transcription, but not translation rates to the rate of cell division can result in protein concentration and noise homeostasis across conditions. Interestingly, we find that the increased cell size at fast division rates, observed in E. coli and other unicellular organisms, buffers noise levels even for proteins with decreased expression at faster growth. We then investigate the functional importance of these regulations using gene regulatory networks that exhibit bi-stability and oscillations. We find that network topology affects robustness to changes in division rate in complex and unexpected ways. In particular, a simple model of persistence, based on global physiological feedback, predicts increased proportion of persister cells at slow division rates. Altogether, our study reveals how cell size regulation in response to cell division rate could help controlling gene expression noise. It also highlights that understanding circuits' robustness across growth conditions is key for the effective design of synthetic biological systems.
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Affiliation(s)
- François Bertaux
- Department of Mathematics, Imperial College London, London SW7 2AZ,UK
- MRC London Institute of Medical Sciences (LMS), London W12 0NN, UK
- Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, UK
| | - Samuel Marguerat
- MRC London Institute of Medical Sciences (LMS), London W12 0NN, UK
- Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, UK
| | - Vahid Shahrezaei
- Department of Mathematics, Imperial College London, London SW7 2AZ,UK
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39
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Mandell JB, Deslouches B, Montelaro RC, Shanks RMQ, Doi Y, Urish KL. Elimination of Antibiotic Resistant Surgical Implant Biofilms Using an Engineered Cationic Amphipathic Peptide WLBU2. Sci Rep 2017; 7:18098. [PMID: 29273750 PMCID: PMC5741726 DOI: 10.1038/s41598-017-17780-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 11/28/2017] [Indexed: 01/31/2023] Open
Abstract
Antibiotics are unable to remove biofilms from surgical implants. This high antibiotic tolerance is related to bacterial persisters, a sub-population of bacteria phenotypically tolerant to antibiotics secondary to a reduced metabolic state. WLBU2 is an engineered cationic amphipathic peptide designed to maximize antimicrobial activity with minimal mammalian cell toxicity. The objective of this study was to test the ability of WLBU2 to remove Staphylococcus aureus surgical implant biofilms. WLBU2 effectively treated S. aureus biofilms formed by a variety of clinical MSSA and MRSA strains and created culture-negative implants in the in vitro biofilm model. Blocking bacterial metabolism by inhibiting oxidative phosphorylation did not affect WLBU2 killing compared to decreased killing by cefazolin. In the surgical implant infection animal model, WLBU2 decreased biofilm mass as compared to control, untreated samples. WLBU2 could rapidly eliminate implants in vitro and had sufficient efficacy in vivo with minimal systemic toxicity.
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Affiliation(s)
- Jonathan B Mandell
- Arthritis and Arthroplasty Design Group, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA
| | - Berthony Deslouches
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ronald C Montelaro
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, USA
| | - Robert M Q Shanks
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yohei Doi
- Division of Infectious Diseases, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kenneth L Urish
- Arthritis and Arthroplasty Design Group, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
- The Magee Bone and Joint Center, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
- Clinical & Translational Science Institute, University of Pittsburgh, Pittsburgh, PA, USA.
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA.
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40
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Sahukhal GS, Pandey S, Elasri MO. msaABCR operon is involved in persister cell formation in Staphylococcus aureus. BMC Microbiol 2017; 17:218. [PMID: 29166860 PMCID: PMC5700755 DOI: 10.1186/s12866-017-1129-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 11/15/2017] [Indexed: 02/02/2023] Open
Abstract
Background Persister cells comprise a phenotypic variant that shows extreme antibiotic tolerance resulting in treatment failures of bacterial infections. While this phenomenon has posed a great threat in public health, mechanisms underlying their formation in Staphylococcus aureus remain largely unknown. Increasing evidences of the presence of persister cells in recalcitrant infections underscores the great urgency to unravel the mechanism by which these cells develop. Previously, we characterized msaABCR operon that plays roles in regulation of virulence, biofilm development and antibiotic resistance. We also characterized the function of MsaB protein and showed that MsaB is a putative transcription factor that binds target DNA in response to nutrients availability. Results In this study, we compared the number of persister cell in wild type, msaABCR deletion mutant and the complemented strain in two backgrounds USA300 LAC and Mu50. Herein, we report that msaABCR deletion mutant forms significantly less number of persister cells relative to wild type after challenge with various antibiotics in planktonic and biofilm growth conditions. Complementation of the msaABCR operon restored wild type phenotype. Combined antibiotic therapy along with msaABCR deletion significantly improves the killing kinetics of stationary phase and biofilm S. aureus cells. Transcriptomics analysis showed that msaABCR regulates several metabolic genes, transcription factors, transporters and enzymes that may play role in persister cells formation, which we seek to define in the future. Conclusions This study presented a new regulator, msaABCR operon, that is involved in the persister cells formation, which is a poorly understood in S. aureus. Indeed, we showed that msaABCR deletion significantly reduces the persister cells formation in all growth phases tested. Although, we have not yet defined the mechanism, we have shown that msaABCR regulates several metabolic, transporters, and extracellular proteases genes that have been previously linked with persister cells formation in other bacterial systems. Taken together, this study showed that inactivation of the msaABCR operon enhances the effectiveness of antibiotics for the treatment of S. aureus infections, especially in context of persister cells. Electronic supplementary material The online version of this article (10.1186/s12866-017-1129-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gyan S Sahukhal
- Department of Biological Sciences, The University of Southern Mississippi, 118 College Drive # 5018, Hattiesburg, MS, 39406-0001, USA
| | - Shanti Pandey
- Department of Biological Sciences, The University of Southern Mississippi, 118 College Drive # 5018, Hattiesburg, MS, 39406-0001, USA
| | - Mohamed O Elasri
- Department of Biological Sciences, The University of Southern Mississippi, 118 College Drive # 5018, Hattiesburg, MS, 39406-0001, USA.
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41
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Tian C, Semsey S, Mitarai N. Synchronized switching of multiple toxin-antitoxin modules by (p)ppGpp fluctuation. Nucleic Acids Res 2017; 45:8180-8189. [PMID: 28854732 PMCID: PMC5737467 DOI: 10.1093/nar/gkx552] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 06/15/2017] [Indexed: 11/16/2022] Open
Abstract
Toxin–antitoxin (TA) loci are widespread in bacteria including important pathogenic species. Recent studies suggest that TA systems play a key role in persister formation. However, the persistence phenotype shows only weak dependence on the number of TA systems, i.e. they are functionally redundant. We use a mathematical model to investigate the interaction of multiple TA systems in the switching between growth and persistence. We explore two scenarios: (i) TA systems are bistable and each TA system experiences its own noise and (ii) the noise in the level of common stress signal (e.g. (p)ppGpp) coordinates all TA systems simultaneously. We find that in the first scenario the exit from the persister state strongly depends on the number of TA systems. However in the second case, we could reproduce the weak dependence. The duration of the high (p)ppGpp state was found to be the key parameter for persistence. The (p)ppGpp-driven synchronized transition of all TA systems results in the redundancy.
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Affiliation(s)
- Chengzhe Tian
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen Ø, Denmark
| | - Szabolcs Semsey
- Department of Biology, University of Copenhagen, Ole Maal?es Vej 5, 2200 Copenhagen N, Denmark
| | - Namiko Mitarai
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen Ø, Denmark
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42
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Sprenger H, Kienesberger S, Pertschy B, Pöltl L, Konrad B, Bhutada P, Vorkapic D, Atzmüller D, Feist F, Högenauer C, Gorkiewicz G, Zechner EL. Fic Proteins of Campylobacter fetus subsp. venerealis Form a Network of Functional Toxin-Antitoxin Systems. Front Microbiol 2017; 8:1965. [PMID: 29089929 PMCID: PMC5651007 DOI: 10.3389/fmicb.2017.01965] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 09/25/2017] [Indexed: 01/02/2023] Open
Abstract
Enzymes containing the FIC (filamentation induced by cyclic AMP) domain catalyze post-translational modifications of target proteins. In bacteria the activity of some Fic proteins resembles classical toxin–antitoxin (TA) systems. An excess of toxin over neutralizing antitoxin can enable bacteria to survive some stress conditions by slowing metabolic processes and promoting dormancy. The cell can return to normal growth when sufficient antitoxin is present to block toxin activity. Fic genes of the human and animal pathogen Campylobacter fetus are significantly associated with just one subspecies, which is specifically adapted to the urogenital tract. Here, we demonstrate that the fic genes of virulent isolate C. fetus subsp. venerealis 84-112 form multiple TA systems. Expression of the toxins in Escherichia coli caused filamentation and growth inhibition phenotypes reversible by concomitant antitoxin expression. Key active site residues involved in adenylylation by Fic proteins are conserved in Fic1, Fic3 and Fic4, but degenerated in Fic2. We show that both Fic3 and the non-canonical Fic2 disrupt assembly and function of E. coli ribosomes when expressed independently of a trans-acting antitoxin. Toxicity of the Fic proteins is controlled by different mechanisms. The first involves intramolecular regulation by an inhibitory helix typical for Fic proteins. The second is an unusual neutralization by heterologous Fic–Fic protein interactions. Moreover, a small interacting antitoxin called Fic inhibitory protein 3, which appears unrelated to known Fic antitoxins, has the novel capacity to bind and neutralize Fic toxins encoded in cis and at distant sites. These findings reveal a remarkable system of functional crosstalk occurring between Fic proteins expressed from chromosomal and extrachromosomal modules. Conservation of fic genes in other bacteria that either inhabit or establish pathology in the urogenital tract of humans and animals underscores the significance of these factors for niche-specific adaptation and virulence.
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Affiliation(s)
- Hanna Sprenger
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,Institute of Pathology, Medical University of Graz, Graz, Austria.,Division of Gastroenterology and Hepatology, Medical University of Graz, Graz, Austria
| | - Sabine Kienesberger
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,Institute of Pathology, Medical University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria
| | - Brigitte Pertschy
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Lisa Pöltl
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Bettina Konrad
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Priya Bhutada
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Dina Vorkapic
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Denise Atzmüller
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Florian Feist
- Vehicle Safety Institute, Graz University of Technology, Graz, Austria
| | - Christoph Högenauer
- Division of Gastroenterology and Hepatology, Medical University of Graz, Graz, Austria
| | - Gregor Gorkiewicz
- Institute of Pathology, Medical University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria
| | - Ellen L Zechner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria
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Shidore T, Triplett LR. Toxin-Antitoxin Systems: Implications for Plant Disease. ANNUAL REVIEW OF PHYTOPATHOLOGY 2017; 55:161-179. [PMID: 28525308 DOI: 10.1146/annurev-phyto-080516-035559] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Toxin-antitoxin (TA) systems are gene modules that are ubiquitous in free-living prokaryotes. Diverse in structure, cellular function, and fitness roles, TA systems are defined by the presence of a toxin gene that suppresses bacterial growth and a toxin-neutralizing antitoxin gene, usually encoded in a single operon. Originally viewed as DNA maintenance modules, TA systems are now thought to function in many roles, including bacterial stress tolerance, virulence, phage defense, and biofilm formation. However, very few studies have investigated the significance of TA systems in the context of plant-microbe interactions. This review discusses the potential impact and application of TA systems in plant-associated bacteria, guided by insights gained from animal-pathogenic model systems.
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Affiliation(s)
- T Shidore
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511:
| | - L R Triplett
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511:
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Abstract
The interaction between the host and the pathogen is extremely complex and is affected by anatomical, physiological, and immunological diversity in the microenvironments, leading to phenotypic diversity of the pathogen. Phenotypic heterogeneity, defined as nongenetic variation observed in individual members of a clonal population, can have beneficial consequences especially in fluctuating stressful environmental conditions. This is all the more relevant in infections caused by Mycobacterium tuberculosis wherein the pathogen is able to survive and often establish a lifelong persistent infection in the host. Recent studies in tuberculosis patients and in animal models have documented the heterogeneous and diverging trajectories of individual lesions within a single host. Since the fate of the individual lesions appears to be determined by the local tissue environment rather than systemic response of the host, studying this heterogeneity is very relevant to ensure better control and complete eradication of the pathogen from individual lesions. The heterogeneous microenvironments greatly enhance M. tuberculosis heterogeneity influencing the growth rates, metabolic potential, stress responses, drug susceptibility, and eventual lesion resolution. Single-cell approaches such as time-lapse microscopy using microfluidic devices allow us to address cell-to-cell variations that are often lost in population-average measurements. In this review, we focus on some of the factors that could be considered as drivers of phenotypic heterogeneity in M. tuberculosis as well as highlight some of the techniques that are useful in addressing this issue.
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Carvalho G, Guilhen C, Balestrino D, Forestier C, Mathias JD. Relating switching rates between normal and persister cells to substrate and antibiotic concentrations: a mathematical modelling approach supported by experiments. Microb Biotechnol 2017; 10:1616-1627. [PMID: 28730700 PMCID: PMC5658594 DOI: 10.1111/1751-7915.12739] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 05/03/2017] [Accepted: 05/04/2017] [Indexed: 11/29/2022] Open
Abstract
We developed and compared two mathematical models of variable phenotypic switching rates between normal and persister cells that depend on substrate concentration and antibiotic presence. They could be used to simulate the formation of persisters in environments with concentration gradients such as biofilms. Our models are extensions of a previous model of the dynamics of normal and persistent cell populations developed by Balaban et al. (2004, Science 305: 1622). We calibrated the models’ parameters with experimental killing curves obtained after ciprofloxacin treatment of samples regularly harvested from planktonic batch cultures of Klebsiella pneumoniae. Our switching models accurately reproduced the dynamics of normal and persistent populations in planktonic batch cultures and under antibiotic treatment. Results showed that the models are valid for a large range of substrate concentrations and for zero or high doses of antibiotics.
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Affiliation(s)
- Gabriel Carvalho
- UR LISC Laboratoire d'ingénierie pour les systèmes complexes, Irstea, Aubière, France
| | - Cyril Guilhen
- LMGE, UMR6023 CNRS, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Damien Balestrino
- LMGE, UMR6023 CNRS, Université Clermont Auvergne, Clermont-Ferrand, France
| | | | - Jean-Denis Mathias
- UR LISC Laboratoire d'ingénierie pour les systèmes complexes, Irstea, Aubière, France
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46
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Andersen SB, Ghoul M, Griffin AS, Petersen B, Johansen HK, Molin S. Diversity, Prevalence, and Longitudinal Occurrence of Type II Toxin-Antitoxin Systems of Pseudomonas aeruginosa Infecting Cystic Fibrosis Lungs. Front Microbiol 2017; 8:1180. [PMID: 28690609 PMCID: PMC5481352 DOI: 10.3389/fmicb.2017.01180] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Accepted: 06/09/2017] [Indexed: 12/15/2022] Open
Abstract
Type II toxin-antitoxin (TA) systems are most commonly composed of two genes encoding a stable toxin, which harms the cell, and an unstable antitoxin that can inactivate it. TA systems were initially characterized as selfish elements, but have recently gained attention for regulating general stress responses responsible for pathogen virulence, formation of drug-tolerant persister cells and biofilms—all implicated in causing recalcitrant chronic infections. We use a bioinformatics approach to explore the distribution and evolution of type II TA loci of the opportunistic pathogen, Pseudomonas aeruginosa, across longitudinally sampled isolates from cystic fibrosis lungs. We identify their location in the genome, mutations, and gain/loss during infection to elucidate their function(s) in stabilizing selfish elements and pathogenesis. We found (1) 26 distinct TA systems, where all isolates harbor four in their core genome and a variable number of the remaining 22 on genomic islands; (2) limited mutations in core genome TA loci, suggesting they are not under negative selection; (3) no evidence for horizontal transmission of elements with TA systems between clone types within patients, despite their ability to mobilize; (4) no gain and limited loss of TA-bearing genomic islands, and of those elements partially lost, the remnant regions carry the TA systems supporting their role in genomic stabilization; (5) no significant correlation between frequency of TA systems and strain ability to establish as chronic infection, but those with a particular TA, are more successful in establishing a chronic infection.
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Affiliation(s)
- Sandra B Andersen
- Department of Zoology, University of OxfordOxford, United Kingdom.,The Novo Nordisk Foundation Center for Biosustainability, Technical University of DenmarkLyngby, Denmark
| | - Melanie Ghoul
- Department of Zoology, University of OxfordOxford, United Kingdom
| | | | - Bent Petersen
- Department of Bio and Health Informatics, Technical University of DenmarkLyngby, Denmark
| | - Helle K Johansen
- Department of Clinical Microbiology, RigshospitaletCopenhagen, Denmark
| | - Søren Molin
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of DenmarkLyngby, Denmark
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47
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Senissar M, Manav MC, Brodersen DE. Structural conservation of the PIN domain active site across all domains of life. Protein Sci 2017; 26:1474-1492. [PMID: 28508407 DOI: 10.1002/pro.3193] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 05/08/2017] [Accepted: 05/08/2017] [Indexed: 01/26/2023]
Abstract
The PIN (PilT N-terminus) domain is a compact RNA-binding protein domain present in all domains of life. This 120-residue domain consists of a central and parallel β sheet surrounded by α helices, which together organize 4-5 acidic residues in an active site that binds one or more divalent metal ions and in many cases has endoribonuclease activity. In bacteria and archaea, the PIN domain is primarily associated with toxin-antitoxin loci, consisting of a toxin (the PIN domain nuclease) and an antitoxin that inhibits the function of the toxin under normal growth conditions. During nutritional or antibiotic stress, the antitoxin is proteolytically degraded causing activation of the PIN domain toxin leading to a dramatic reprogramming of cellular metabolism to cope with the new situation. In eukaryotes, PIN domains are commonly found as parts of larger proteins and are involved in a range of processes involving RNA cleavage, including ribosomal RNA biogenesis and nonsense-mediated mRNA decay. In this review, we provide a comprehensive overview of the structural characteristics of the PIN domain and compare PIN domains from all domains of life in terms of structure, active site architecture, and activity.
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Affiliation(s)
- M Senissar
- Centre for Bacterial Stress Response and Persistence, Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, Aarhus, 8000, Denmark
| | - M C Manav
- Centre for Bacterial Stress Response and Persistence, Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, Aarhus, 8000, Denmark
| | - D E Brodersen
- Centre for Bacterial Stress Response and Persistence, Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, Aarhus, 8000, Denmark
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49
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Mikheecheva NE, Zaychikova MV, Melerzanov AV, Danilenko VN. A Nonsynonymous SNP Catalog of Mycobacterium tuberculosis Virulence Genes and Its Use for Detecting New Potentially Virulent Sublineages. Genome Biol Evol 2017; 9:887-899. [PMID: 28338924 PMCID: PMC5381574 DOI: 10.1093/gbe/evx053] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2017] [Indexed: 02/06/2023] Open
Abstract
Mycobacterium tuberculosis is divided into several distinct lineages, and various genetic markers such as IS-elements, VNTR, and SNPs are used for lineage identification. We propose an M. tuberculosis classification approach based on functional polymorphisms in virulence genes. An M. tuberculosis virulence genes catalog has been established, including 319 genes from various protein groups, such as proteases, cell wall proteins, fatty acid and lipid metabolism proteins, sigma factors, toxin–antitoxin systems. Another catalog of 1,573 M. tuberculosis isolates of different lineages has been developed. The developed SNP-calling program has identified 3,563 nonsynonymous SNPs. The constructed SNP-based phylogeny reflected the evolutionary relationship between lineages and detected new sublineages. SNP analysis of sublineage F15/LAM4/KZN revealed four lineage-specific mutations in cyp125, mce3B, vapC25, and vapB34. The Ural lineage has been divided into two geographical clusters based on different SNPs in virulence genes. A new sublineage, B0/N-90, was detected inside the Beijing-B0/W-148 by SNPs in irtB, mce3F and vapC46. We have found 27 members of B0/N-90 among the 227 available genomes of the Beijing-B0/W-148 sublineage. Whole-genome sequencing of strain B9741, isolated from an HIV-positive patient, was demonstrated to belong to the new B0/N-90 group. A primer set for PCR detection of B0/N-90 lineage-specific mutations has been developed. The prospective use of mce3 mutant genes as genetically engineered vaccine is discussed.
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Affiliation(s)
- Natalya E Mikheecheva
- Vavilov Institute of General Genetics, Moscow, Russia.,Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | | | | | - Valery N Danilenko
- Vavilov Institute of General Genetics, Moscow, Russia.,Scientific Research Center of Biotechnology of Antibiotics BIOAN, Moscow, Russia
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50
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Physical and Functional Interplay between MazF 1Bif and Its Noncognate Antitoxins from Bifidobacterium longum. Appl Environ Microbiol 2017; 83:AEM.03232-16. [PMID: 28213540 DOI: 10.1128/aem.03232-16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 02/09/2017] [Indexed: 11/20/2022] Open
Abstract
Bifidobacterium longum strain JDM301, a widely used commercial strain in China, encodes at least two MazEF-like modules and one RelBE-like toxin-antitoxin (TA) system in its chromosome, designated MazE1F1Bif, MazE2F2Bif, and RelBEBif, respectively. Bacterial TA systems play an important role in several stress responses, but the relationship between these TA systems is largely unknown. In this study, the interactions between MazF1Bif and MazE2Bif or RelBBif were assessed in B. longum strain JDM301. MazF1Bif caused the degradation of tufABif mRNA, and its toxicity was inhibited by forming a protein complex with its cognate antitoxin, MazE1Bif Notably, MazF1Bif toxicity was also partially neutralized when jointly expressed with noncognate antitoxin MazE2Bif or RelBBif Our results show that the two noncognate antitoxins also inhibited mRNA degradation caused by MazF1Bif toxin. Furthermore, the physical interplay between MazF1Bif and its noncognate antitoxins was confirmed by immunoprecipitation. These results suggest that MazF1Bif can arrest cell growth and that MazF1Bif toxicity can be neutralized by its cognate and noncognate antitoxins. These results imply that JDM301 uses a sophisticated toxin-antitoxin interaction network to alter its physiology when coping with environmental stress.IMPORTANCE Although toxin-antitoxin (TA) systems play an important role in several stress responses, the regulatory mechanisms of multiple TA system homologs in the bacterial genome remain largely unclear. In this study, the relationships between MazE1F1Bif and the other two TA systems of Bifidobacterium longum strain JDM301 were explored, and the interactions between MazF1Bif and MazE2Bif or RelBBif were characterized. In addition, the mRNA degradation activity of MazF1Bif was demonstrated. In particular, the interaction of the toxin with noncognate antitoxins was shown, even between different TA families (MazF1Bif toxin and RelBBif antitoxin) in JDM301. This work provides insight into the regulatory mechanisms of TA systems implicated in the stress responses of bifidobacteria.
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