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Alfei S, Schito GC, Schito AM, Zuccari G. Reactive Oxygen Species (ROS)-Mediated Antibacterial Oxidative Therapies: Available Methods to Generate ROS and a Novel Option Proposal. Int J Mol Sci 2024; 25:7182. [PMID: 39000290 PMCID: PMC11241369 DOI: 10.3390/ijms25137182] [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: 05/23/2024] [Revised: 06/22/2024] [Accepted: 06/27/2024] [Indexed: 07/16/2024] Open
Abstract
The increasing emergence of multidrug-resistant (MDR) pathogens causes difficult-to-treat infections with long-term hospitalizations and a high incidence of death, thus representing a global public health problem. To manage MDR bacteria bugs, new antimicrobial strategies are necessary, and their introduction in practice is a daily challenge for scientists in the field. An extensively studied approach to treating MDR infections consists of inducing high levels of reactive oxygen species (ROS) by several methods. Although further clinical investigations are mandatory on the possible toxic effects of ROS on mammalian cells, clinical evaluations are extremely promising, and their topical use to treat infected wounds and ulcers, also in presence of biofilm, is already clinically approved. Biochar (BC) is a carbonaceous material obtained by pyrolysis of different vegetable and animal biomass feedstocks at 200-1000 °C in the limited presence of O2. Recently, it has been demonstrated that BC's capability of removing organic and inorganic xenobiotics is mainly due to the presence of persistent free radicals (PFRs), which can activate oxygen, H2O2, or persulfate in the presence or absence of transition metals by electron transfer, thus generating ROS, which in turn degrade pollutants by advanced oxidation processes (AOPs). In this context, the antibacterial effects of BC-containing PFRs have been demonstrated by some authors against Escherichia coli and Staphylococcus aureus, thus giving birth to our idea of the possible use of BC-derived PFRs as a novel method capable of inducing ROS generation for antimicrobial oxidative therapy. Here, the general aspects concerning ROS physiological and pathological production and regulation and the mechanism by which they could exert antimicrobial effects have been reviewed. The methods currently adopted to induce ROS production for antimicrobial oxidative therapy have been discussed. Finally, for the first time, BC-related PFRs have been proposed as a new source of ROS for antimicrobial therapy via AOPs.
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Affiliation(s)
- Silvana Alfei
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano, 4, 16148 Genoa, Italy
| | - Gian Carlo Schito
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa, Viale Benedetto XV, 6, 16132 Genoa, Italy
| | - Anna Maria Schito
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa, Viale Benedetto XV, 6, 16132 Genoa, Italy
| | - Guendalina Zuccari
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano, 4, 16148 Genoa, Italy
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Sharma PV, Jain S, Sen R. Peptides designed from a bacteriophage capsid protein function as synthetic transcription repressors. J Biol Chem 2023; 299:105373. [PMID: 37865318 PMCID: PMC10692717 DOI: 10.1016/j.jbc.2023.105373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 10/08/2023] [Accepted: 10/11/2023] [Indexed: 10/23/2023] Open
Abstract
The bacteriophage capsid protein, Psu (polarity suppression), inhibits the bacterial transcription terminator, Rho. In an effort to find nontraditional antibacterial agents, we previously designed peptides from the Psu C terminus that function as inhibitors of Rho. Here, we demonstrated that these peptides have positive surface-charge densities, and they downregulate many genes in Escherichia coli. We hypothesized that these peptides could bind to nucleic acids and repress gene expression. One of these peptides, peptide 33, represses in vitro transcription from the T7A1 and Plac promoters efficiently by blocking the access of RNA polymerase to the promoter, a mode of transcription repression akin to many bacterial repressors. In vivo, expressions of the peptides reduce the total RNA level as well as transcription from Plac and Posm promoters significantly. However, they are less efficient in repressing transcription from the rRNA promoters with a very high turnover of RNA polymerase. The peptide 33 binds to both single and dsDNA as well as to RNA with dissociation constants ranging from 1 to 5 μM exhibiting preferences for the single-stranded DNA and RNAs. These interactions are salt-resistant and not sequence-specific. Interactions with dsDNA are entropy-driven, while it is enthalpy-driven for the ssDNA. This mode of interaction with nucleic acids is similar to many nonspecific ssDNA-binding proteins. Expression of peptide 33 induces cell elongation and impaired cell division, possibly due to the dislodging of the DNA-binding proteins. Overall, we surmised that these synthetic transcription repressors would function like bacterial nucleoid-associated proteins.
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Affiliation(s)
- Pankaj V Sharma
- Laboratory of Transcription, Center for DNA Fingerprinting and Diagnostics, Hyderabad, India; Graduate Studies, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Sriyans Jain
- Laboratory of Transcription, Center for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | - Ranjan Sen
- Laboratory of Transcription, Center for DNA Fingerprinting and Diagnostics, Hyderabad, India.
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3
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Kim K, Wang T, Ma HR, Şimşek E, Li B, Andreani V, You L. Mapping single‐cell responses to population‐level dynamics during antibiotic treatment. Mol Syst Biol 2023; 19:e11475. [PMCID: PMC10333910 DOI: 10.15252/msb.202211475] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 04/24/2023] [Accepted: 04/25/2023] [Indexed: 12/08/2023] Open
Abstract
Treatment of sensitive bacteria with beta‐lactam antibiotics often leads to two salient population‐level features: a transient increase in total population biomass before a subsequent decline, and a linear correlation between growth and killing rates. However, it remains unclear how these population‐level responses emerge from collective single‐cell responses. During beta‐lactam treatment, it is well‐recognized that individual cells often exhibit varying degrees of filamentation before lysis. We show that the cumulative probability of cell lysis increases sigmoidally with the extent of filamentation and that this dependence is characterized by unique parameters that are specific to bacterial strain, antibiotic dose, and growth condition. Modeling demonstrates how the single‐cell lysis probabilities can give rise to population‐level biomass dynamics, which were experimentally validated. This mapping provides insights into how the population biomass time‐kill curve emerges from single cells and allows the representation of both single‐ and population‐level responses with universal parameters.
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Affiliation(s)
- Kyeri Kim
- Department of Biomedical EngineeringDuke UniversityDurhamNCUSA
- Center for Quantitative BiodesignDuke UniversityDurhamNCUSA
| | - Teng Wang
- Department of Biomedical EngineeringDuke UniversityDurhamNCUSA
- Center for Quantitative BiodesignDuke UniversityDurhamNCUSA
| | - Helena R Ma
- Department of Biomedical EngineeringDuke UniversityDurhamNCUSA
- Center for Quantitative BiodesignDuke UniversityDurhamNCUSA
| | - Emrah Şimşek
- Department of Biomedical EngineeringDuke UniversityDurhamNCUSA
- Center for Quantitative BiodesignDuke UniversityDurhamNCUSA
| | - Boyan Li
- Integrated Science Program, Yuanpei CollegePeking UniversityBeijingChina
| | - Virgile Andreani
- Biomedical Engineering DepartmentBoston UniversityBostonMAUSA
- Biological Design CenterBoston UniversityBostonMAUSA
| | - Lingchong You
- Department of Biomedical EngineeringDuke UniversityDurhamNCUSA
- Center for Quantitative BiodesignDuke UniversityDurhamNCUSA
- Center for Genomic and Computational BiologyDuke UniversityDurhamNCUSA
- Department of Molecular Genetics and MicrobiologyDuke University School of MedicineDurhamNCUSA
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4
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Lv Z, Cao Y, Xue D, Zhang H, Zhou S, Yin N, Li W, Jin L, Wang Y, Zhang H. A multiphoton transition activated iron based metal organic framework for synergistic therapy of photodynamic therapy/chemodynamic therapy/chemotherapy for orthotopic gliomas. J Mater Chem B 2023; 11:1100-1107. [PMID: 36629834 DOI: 10.1039/d2tb02273g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Although photodynamic therapy (PDT) has exhibited good potential in therapy of gliomas, the limited penetration depth of light and the obstacle of the blood-brain barrier (BBB) lead to unsatisfactory treatment effects. Herein, a multifunctional nanodrug (UMD) was constructed with up-conversion nanoparticles (NaGdF4:Yb,Tm@NaYF4:Yb,Nd@NaYF4, UCNPs) as the core, the photosensitizer NH2-MIL-53 (Fe) as the shell and a carrier for loading chemotherapy drug doxorubicin hydrochloride (Dox) for synergistic therapy of gliomas. Lactoferrin (LF) was finally modified on the surface of the UMD to endow it with the ability to traverse the BBB and target cells (UMDL). The UCNP core can convert 808 nm near-infrared (NIR) light to ultraviolet light (UV light) for exciting NH2-MIL-53 (Fe), achieving NIR-mediated PDT. In addition, Fe3+ on the surface of the NH2-MIL-53 (Fe) shell could be reduced to Fe2+ in a tumor microenvironment (TME), and then reacted with over-expressed H2O2 in the TME to generate hydroxyl radicals (˙OH) for chemodynamic therapy (CDT). The Dox drug could be released in response to acidic conditions in the TME, inhibiting the growth of gliomas with low side effects. The synergistic effect of PDT/CDT/chemotherapy leads to effective suppression of orthotopic gliomas.
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Affiliation(s)
- Zhijia Lv
- School of Rare Earths, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.,Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou, Jiangxi, 341000, P. R. China
| | - Yue Cao
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun 130041, P. R. China
| | - Dongzhi Xue
- School of Rare Earths, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.,State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry (CIAC), Chinese Academy of Sciences, Changchun, 130022, P. R. China.
| | - Hao Zhang
- School of Rare Earths, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.,State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry (CIAC), Chinese Academy of Sciences, Changchun, 130022, P. R. China.
| | - Shijie Zhou
- School of Rare Earths, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.,Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou, Jiangxi, 341000, P. R. China
| | - Na Yin
- School of Rare Earths, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.,State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry (CIAC), Chinese Academy of Sciences, Changchun, 130022, P. R. China.
| | - Wanying Li
- School of Rare Earths, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.,State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry (CIAC), Chinese Academy of Sciences, Changchun, 130022, P. R. China.
| | - Longhai Jin
- Department of Radiology, The Second Hospital of Jilin University, Changchun 130041, P. R. China
| | - Yinghui Wang
- School of Rare Earths, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.,State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry (CIAC), Chinese Academy of Sciences, Changchun, 130022, P. R. China.
| | - Hongjie Zhang
- School of Rare Earths, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.,Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou, Jiangxi, 341000, P. R. China.,State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry (CIAC), Chinese Academy of Sciences, Changchun, 130022, P. R. China. .,Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China
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5
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Aribisala JO, Sabiu S. Redox Impact on Bacterial Macromolecule: A Promising Avenue for Discovery and Development of Novel Antibacterials. Biomolecules 2022; 12:1545. [PMID: 36358894 PMCID: PMC9688007 DOI: 10.3390/biom12111545] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/20/2022] [Accepted: 10/20/2022] [Indexed: 07/30/2023] Open
Abstract
Antibiotic resistance in bacteria has remained a serious public health concern, resulting in substantial deaths and morbidity each year. Factors such as mutation and abuse of currently available antibiotics have contributed to the bulk of the menace. Hence, the introduction and implementation of new therapeutic strategies are imperative. Of these strategies, data supporting the role of reactive oxygen species (ROS) in bacterial lethality are intriguing, with several antimicrobials, including antibiotics such as fluoroquinolones, β-lactams, and aminoglycosides, as well as natural plant compounds, being remarkably implicated. Following treatment with ROS-inducing antimicrobials, ROS such as O2•-, •OH, and H2O2 generated in bacteria, which the organism is unable to detoxify, damage cellular macromolecules such as proteins, lipids, and nucleic acids and results in cell death. Despite the unique mechanism of action of ROS-inducing antibacterials and significant studies on ROS-mediated means of bacterial killing, the field remains a topical one, with contradicting viewpoints that require frequent review. Here, we appraised the antibacterial agents (antibiotics, natural and synthetic compounds) implicated in ROS generation and the safety concerns associated with their usage. Further, background information on the sources and types of ROS in bacteria, the mechanism of bacterial lethality via oxidative stress, as well as viewpoints on the ROS hypothesis undermining and solidifying this concept are discussed.
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Hu X, Fu Y, Shi H, Xu W, Shen C, Hu B, Ma L, Lou L. Neglected resistance risks: Cooperative resistance of antibiotic resistant bacteria influenced by primary soil components. JOURNAL OF HAZARDOUS MATERIALS 2022; 429:128229. [PMID: 35074748 DOI: 10.1016/j.jhazmat.2022.128229] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 01/04/2022] [Accepted: 01/04/2022] [Indexed: 06/14/2023]
Abstract
Various antibiotic resistant bacteria (ARB) can thrive in soil and resist such environmental pressures as antibiotics through cooperative resistance, thereby promoting ARB retention and antibiotic resistance genes transmission. However, there has been finite knowledge in regard to the mechanisms and potential ecological risks of cooperative resistance in soil microbiome. In this study, soil minerals and organic matters were designed to treat a mixture of two Escherichia coli strains with different antibiotic resistance (E. coli DH5α/pUC19 and E. coli XL2-Blue) to determine how soil components affected cooperative resistance, and Luria-Bertani plates containing two antibiotics were used to observe dual-drug resistant bacteria (DRB) developed via cooperative resistance. Results showed quartz, humic acid, and biochar promoted E. coli XL2-Blue with high fitness costs, whereas kaolin, montmorillonite, and soot inhibited both strains. Using fluorescence microscope and PCR, it was speculated DRB could resist the antibiotic pressure via E. coli XL2-Blue coating E. coli DH5α/pUC19. E. coli DH5α/pUC19 dominated cooperative resistance. Correlation analysis and scanning electron microscope images indicated soil components influenced cooperative resistance. Biochar promoted cooperative resistance by increasing intracellular reactive oxygen species, thereby reducing the dominant strain concentration required for DRB development. Kaolin inhibited cooperative resistance the most, followed by soot and montmorillonite.
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Affiliation(s)
- Xinyi Hu
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310029, People's Republic of China
| | - Yulong Fu
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310029, People's Republic of China
| | - Hongyu Shi
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310029, People's Republic of China
| | - Weijian Xu
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310029, People's Republic of China
| | - Chaofeng Shen
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310029, People's Republic of China; Key Laboratory of Water Pollution Control and Environmental Safety of Zhejiang Province, 310020, People's Republic of China
| | - Baolan Hu
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310029, People's Republic of China; Key Laboratory of Water Pollution Control and Environmental Safety of Zhejiang Province, 310020, People's Republic of China
| | - Liping Ma
- School of Ecological and Environmental Sciences, Technology Innovation Center for Land Spatial Eco-restoration in Metropolitan Area, Ministry of Natural Resources, East China Normal University, Shanghai 200062, People's Republic of China.
| | - Liping Lou
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310029, People's Republic of China; Key Laboratory of Water Pollution Control and Environmental Safety of Zhejiang Province, 310020, People's Republic of China.
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7
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Vaishampayan A, Grohmann E. Antimicrobials Functioning through ROS-Mediated Mechanisms: Current Insights. Microorganisms 2021; 10:microorganisms10010061. [PMID: 35056511 PMCID: PMC8779550 DOI: 10.3390/microorganisms10010061] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/22/2021] [Accepted: 12/24/2021] [Indexed: 12/22/2022] Open
Abstract
Antibiotic resistance and infections caused by multidrug-resistant bacteria are global health concerns. Reducing the overuse and misuse of antibiotics is the primary step toward minimizing the antibiotic resistance crisis. Thus, it is imperative to introduce and implement novel antimicrobial strategies. Recently, several alternative antimicrobials targeting oxidative stress in bacteria have been studied and shown to be promising. Oxidative stress occurs when bacterial cells fail to detoxify the excessive reactive oxygen species (ROS) accumulated in the cells. Bacteria deploy numerous defense mechanisms against oxidative stress. The oxidative stress response is not essential for the normal growth of bacteria, but it is crucial for their survival. This toxic oxidative stress is created by the host immune response or antimicrobials generating ROS. ROS possess strong oxidation potential and cause serious damage to nucleic acids, lipids, and proteins. Since ROS-based antimicrobials target multiple sites in bacteria, these antimicrobials have attracted the attention of several researchers. In this review, we present recent ROS-based alternative antimicrobials and strategies targeting oxidative stress which might help in mitigating the problem of antibiotic resistance and dissemination.
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8
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Oxidative damage blocks thymineless death and trimethoprim poisoning in Escherichia coli. J Bacteriol 2021; 204:e0037021. [PMID: 34633866 DOI: 10.1128/jb.00370-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cells that cannot synthesize one of the DNA precursors, dTTP, due to thyA mutation or metabolic poisoning, undergo thymineless death (TLD), - a chromosome-based phenomenon of unclear mechanisms. In E. coli, thymineless death is caused either by denying thyA mutants thymidine supplementation or by treating wild type cells with trimethoprim. Two recent reports promised a potential breakthrough in TLD understanding, suggesting significant oxidative damage during thymine starvation. Oxidative damage in vivo comes from Fenton's reaction, when hydrogen peroxide meets ferrous iron to produce hydroxyl radical. Therefore, TLD could kill via irreparable double-strand breaks behind replication forks, when starvation-caused single-strand DNA gaps are attacked by hydroxyl radicals. We tested the proposed Fenton-TLD connection, in both thyA mutants denied thymidine, as well as in trimethoprim-treated WT cells, under three conditions: 1) intracellular iron chelation; 2) mutational inactivation of hydrogen peroxide (HP) scavenging; 3) acute treatment with sublethal HP concentrations. We found that TLD kinetics are affected by neither iron chelation, nor HP stabilization in cultures, indicating no induction of oxidative damage during thymine starvation. Moreover, acute exogenous HP treatments completely block TLD, apparently by blocking cell division - which may be a novel TLD prerequisite. Separately, the acute trimethoprim sensitivity of the rffC and recBCD mutants demonstrates how bactericidal power of this antibiotic could be amplified by inhibiting the corresponding enzymes. Importance Mysterious thymineless death strikes cells that are starved for thymine and therefore replicating their chromosomal DNA without dTTP. After 67 years of experiments testing various obvious and not so obvious explanations, thymineless death is still without a mechanism. Recently, oxidative damage via in vivo Fenton's reaction was proposed as a critical contributor to the irreparable chromosome damage during thymine starvation. We have tested this idea by either blocking in vivo Fenton's reaction (expecting no thymineless death) or by amplifying oxidative damage (expecting hyper thymineless death). Instead, we found that blocking Fenton's reaction has no influence on thymineless death, while amplifying oxidative damage prevents thymineless death altogether. Thus, oxidative damage does not contribute to thymineless death, while the latter remains enigmatic.
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Manoalide Shows Mutual Interaction between Cellular and Mitochondrial Reactive Species with Apoptosis in Oral Cancer Cells. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:6667355. [PMID: 33747349 PMCID: PMC7943270 DOI: 10.1155/2021/6667355] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 02/09/2021] [Accepted: 02/11/2021] [Indexed: 01/04/2023]
Abstract
We previously found that marine sponge-derived manoalide induced antiproliferation and apoptosis of oral cancer cells as well as reactive species generations probed by dichloro-dihydrofluorescein diacetate (DCFH-DA) and MitoSOX Red. However, the sources of cellular and mitochondrial redox stresses and the mutual interacting effects between these redox stresses and apoptosis remain unclear. To address this issue, we examined a panel of reactive species and used the inhibitors of cellular reactive species (N-acetylcysteine (NAC)), mitochondrial reactive species (MitoTEMPO), and apoptosis (Z-VAD-FMK; ZVAD) to explore their interactions in manoalide-treated oral cancer Ca9-22 and CAL 27 cells. Hydroxyl (˙OH), nitrogen dioxide (NO2˙), nitric oxide (˙NO), carbonate radical-anion (CO3 ˙-), peroxynitrite (ONOO-), and superoxide (O2 ˙-) were increased in oral cancer cells following manoalide treatments in terms of fluorescence staining and flow cytometry. Cellular reactive species (˙OH, NO2 ·, ˙NO, CO3 ˙-, and ONOO-) as well as cellular and mitochondrial reactive species (O2 ˙-) were induced in oral cancer cells following manoalide treatment for 6 h. NAC, MitoTEMPO, and ZVAD inhibit manoalide-induced apoptosis in terms of annexin V and pancaspase activity assays. Moreover, NAC inhibits mitochondrial reactive species and MitoTEMPO inhibits cellular reactive species, suggesting that cellular and mitochondrial reactive species can crosstalk to regulate each other. ZVAD shows suppressing effects on the generation of both cellular and mitochondrial reactive species. In conclusion, manoalide induces reciprocally activation between cellular and mitochondrial reactive species and apoptosis in oral cancer cells.
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Drlica K, Zhao X. Bacterial death from treatment with fluoroquinolones and other lethal stressors. Expert Rev Anti Infect Ther 2020; 19:601-618. [PMID: 33081547 DOI: 10.1080/14787210.2021.1840353] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Lethal stressors, including antimicrobials, kill bacteria in part through a metabolic response proposed to involve reactive oxygen species (ROS). The quinolone anti-bacterials have served as key experimental tools in developing this idea. AREAS COVERED Bacteriostatic and bactericidal action of quinolones are distinguished, with emphasis on the contribution of chromosome fragmentation and ROS accumulation to bacterial death. Action of non-quinolone antibacterials and non-antimicrobial stressors is described to provide a general framework for understanding stress-mediated, bacterial death. EXPERT OPINION Quinolones trap topoisomerases on DNA in reversible complexes that block DNA replication and bacterial growth. At elevated drug concentrations, DNA ends are released from topoisomerase-mediated constraint, leading to the idea that death arises from chromosome fragmentation. However, DNA ends also stimulate repair, which is energetically expensive. An incompletely understood metabolic shift occurs, and ROS accumulate. Even after quinolone removal, ROS continue to amplify, generating secondary and tertiary damage that overwhelms repair and causes death. Repair may also contribute to death directly via DNA breaks arising from incomplete base-excision repair of ROS-oxidized nucleotides. Remarkably, perturbations that interfere with ROS accumulation confer tolerance to many diverse lethal agents.
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Affiliation(s)
| | - Xilin Zhao
- Rutgers University, Newark, NJ, USA.,State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, South Xiang-An Road, Xiang-An District, Xiamen, Fujian Province, China
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11
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Edelmann D, Berghoff BA. Type I toxin-dependent generation of superoxide affects the persister life cycle of Escherichia coli. Sci Rep 2019; 9:14256. [PMID: 31582786 PMCID: PMC6776643 DOI: 10.1038/s41598-019-50668-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 09/17/2019] [Indexed: 12/15/2022] Open
Abstract
Induction of growth stasis by bacterial toxins from chromosomal toxin-antitoxin systems is suspected to favor formation of multidrug-tolerant cells, named persisters. Recurrent infections are often attributed to resuscitation and regrowth of persisters upon termination of antibiotic therapy. Several lines of evidence point to oxidative stress as a crucial factor during the persister life cycle. Here, we demonstrate that the membrane-depolarizing type I toxins TisB, DinQ, and HokB have the potential to provoke reactive oxygen species formation in Escherichia coli. More detailed work with TisB revealed that mainly superoxide is formed, leading to activation of the SoxRS regulon. Deletion of the genes encoding the cytoplasmic superoxide dismutases SodA and SodB caused both a decline in TisB-dependent persisters and a delay in persister recovery upon termination of antibiotic treatment. We hypothesize that expression of depolarizing toxins during the persister formation process inflicts an oxidative challenge. The ability to counteract oxidative stress might determine whether cells will survive and how much time they need to recover from dormancy.
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Affiliation(s)
- Daniel Edelmann
- Institute for Microbiology and Molecular Biology, Justus Liebig University Giessen, 35392, Giessen, Germany
| | - Bork A Berghoff
- Institute for Microbiology and Molecular Biology, Justus Liebig University Giessen, 35392, Giessen, Germany.
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12
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State-of-the-art: functional fluorescent probes for bioimaging and pharmacological research. Acta Pharmacol Sin 2019; 40:717-723. [PMID: 30487651 DOI: 10.1038/s41401-018-0190-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 10/19/2018] [Indexed: 12/14/2022] Open
Abstract
Cardiovascular diseases, neuropsychiatric disorders, and cancers seriously endanger human health. Mechanistic and pharmacological mechanisms of candidate drugs are central to the translational paradigm. Since many signal transduction and molecular events are implicated in these diseases, a novel method to interrogate the key pharmacological mechanisms is required to accelerate innovative drug discovery. Much attention now focuses on the real-time visualization of molecular disease events to yield new insights to the pathogenesis of the diseases. This review focuses on recent advances in the development of chemical probes for imaging pathological events to facilitate the study of the underlying pharmacodynamics and toxicity involved. As reviewed here, optical imaging is now frequently viewed as an indispensable technique in the field of biological research. Promoting interdisciplinary collaboration among chemistry, biology and medicine, is necessary to further refine functional fluorescent probes for diagnostic and therapeutic applications.
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13
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Imlay JA. Where in the world do bacteria experience oxidative stress? Environ Microbiol 2018; 21:521-530. [PMID: 30307099 DOI: 10.1111/1462-2920.14445] [Citation(s) in RCA: 174] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 10/02/2018] [Accepted: 10/07/2018] [Indexed: 11/26/2022]
Abstract
Reactive oxygen species - superoxide, hydrogen peroxide and hydroxyl radicals - have long been suspected of constraining bacterial growth in important microbial habitats and indeed of shaping microbial communities. Over recent decades, studies of paradigmatic organisms such as Escherichia coli, Salmonella typhimurium, Bacillus subtilis and Saccharomyces cerevisiae have pinpointed the biomolecules that oxidants can damage and the strategies by which microbes minimize their injuries. What is lacking is a good sense of the circumstances under which oxidative stress actually occurs. In this MiniReview several potential natural sources of oxidative stress are considered: endogenous ROS formation, chemical oxidation of reduced species at oxic-anoxic interfaces, H2 O2 production by lactic acid bacteria, the oxidative burst of phagocytes and the redox-cycling of secreted small molecules. While all of these phenomena can be reproduced and verified in the lab, the actual quantification of stress in natural habitats remains lacking - and, therefore, we have a fundamental hole in our understanding of the role that oxidative stress actually plays in the biosphere.
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Affiliation(s)
- James A Imlay
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
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Lethality of MalE-LacZ hybrid protein shares mechanistic attributes with oxidative component of antibiotic lethality. Proc Natl Acad Sci U S A 2017; 114:9164-9169. [PMID: 28794281 DOI: 10.1073/pnas.1707466114] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Downstream metabolic events can contribute to the lethality of drugs or agents that interact with a primary cellular target. In bacteria, the production of reactive oxygen species (ROS) has been associated with the lethal effects of a variety of stresses including bactericidal antibiotics, but the relative contribution of this oxidative component to cell death depends on a variety of factors. Experimental evidence has suggested that unresolvable DNA problems caused by incorporation of oxidized nucleotides into nascent DNA followed by incomplete base excision repair contribute to the ROS-dependent component of antibiotic lethality. Expression of the chimeric periplasmic-cytoplasmic MalE-LacZ72-47 protein is an historically important lethal stress originally identified during seminal genetic experiments that defined the SecY-dependent protein translocation system. Multiple, independent lines of evidence presented here indicate that the predominant mechanism for MalE-LacZ lethality shares attributes with the ROS-dependent component of antibiotic lethality. MalE-LacZ lethality requires molecular oxygen, and its expression induces ROS production. The increased susceptibility of mutants sensitive to oxidative stress to MalE-LacZ lethality indicates that ROS contribute causally to cell death rather than simply being produced by dying cells. Observations that support the proposed mechanism of cell death include MalE-LacZ expression being bacteriostatic rather than bactericidal in cells that overexpress MutT, a nucleotide sanitizer that hydrolyzes 8-oxo-dGTP to the monophosphate, or that lack MutM and MutY, DNA glycosylases that process base pairs involving 8-oxo-dGTP. Our studies suggest stress-induced physiological changes that favor this mode of ROS-dependent death.
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15
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Boone CHT, Grove RA, Adamcova D, Seravalli J, Adamec J. Oxidative stress, metabolomics profiling, and mechanism of local anesthetic induced cell death in yeast. Redox Biol 2017; 12:139-149. [PMID: 28236766 PMCID: PMC5328717 DOI: 10.1016/j.redox.2017.01.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/17/2017] [Accepted: 01/19/2017] [Indexed: 11/23/2022] Open
Abstract
The World Health Organization designates lidocaine as an essential medicine in healthcare, greatly increasing the probability of human exposure. Its use has been associated with ROS generation and neurotoxicity. Physiological and metabolomic alterations, and genetics leading to the clinically observed adverse effects have not been temporally characterized. To study alterations that may lead to these undesirable effects, Saccharomyces cerevisiae grown on aerobic carbon sources to stationary phase was assessed over 6h. Exposure of an LC50 dose of lidocaine, increased mitochondrial depolarization and ROS/RNS generation assessed using JC-1, ROS/RNS specific probes, and FACS. Intracellular calcium also increased, assessed by ICP-MS. Measurement of the relative ATP and ADP concentrations indicates an initial 3-fold depletion of ATP suggesting an alteration in the ATP:ADP ratio. At the 6h time point the lidocaine exposed population contained ATP concentrations roughly 85% that of the negative control suggesting the surviving population adapted its metabolic pathways to, at least partially restore cellular bioenergetics. Metabolite analysis indicates an increase of intermediates in the pentose phosphate pathway, the preparatory phase of glycolysis, and NADPH. Oxidative stress produced by lidocaine exposure targets aconitase decreasing its activity with an observed decrease in isocitrate and an increase citrate. Similarly, increases in α-ketoglutarate, malate, and oxaloacetate imply activation of anaplerotic reactions. Antioxidant molecule glutathione and its precursor amino acids, cysteine and glutamate were greatly increased at later time points. Phosphatidylserine externalization suggestive of early phase apoptosis was also observed. Genetic studies using metacaspase null strains showed resistance to lidocaine induced cell death. These data suggest lidocaine induces perpetual mitochondrial depolarization, ROS/RNS generation along with increased glutathione to combat the oxidative cellular environment, glycolytic to PPP cycling of carbon generating NADPH, obstruction of carbon flow through the TCA cycle, decreased ATP generation, and metacaspase dependent apoptotic cell death.
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Affiliation(s)
- Cory H T Boone
- Department of Biochemistry and Redox Biology Center, University of Nebraska - Lincoln, Lincoln, NE, United States of America
| | - Ryan A Grove
- Department of Biochemistry and Redox Biology Center, University of Nebraska - Lincoln, Lincoln, NE, United States of America
| | - Dana Adamcova
- Department of Biochemistry and Redox Biology Center, University of Nebraska - Lincoln, Lincoln, NE, United States of America
| | - Javier Seravalli
- Department of Biochemistry and Redox Biology Center, University of Nebraska - Lincoln, Lincoln, NE, United States of America
| | - Jiri Adamec
- Department of Biochemistry and Redox Biology Center, University of Nebraska - Lincoln, Lincoln, NE, United States of America.
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16
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Kashyap DR, Kuzma M, Kowalczyk DA, Gupta D, Dziarski R. Bactericidal peptidoglycan recognition protein induces oxidative stress in Escherichia coli through a block in respiratory chain and increase in central carbon catabolism. Mol Microbiol 2017. [PMID: 28621879 DOI: 10.1111/mmi.13733] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mammalian Peptidoglycan Recognition Proteins (PGRPs) kill both Gram-positive and Gram-negative bacteria through simultaneous induction of oxidative, thiol and metal stress responses in bacteria. However, metabolic pathways through which PGRPs induce these bactericidal stress responses are unknown. We screened Keio collection of Escherichia coli deletion mutants and revealed that deleting genes for respiratory chain flavoproteins or for tricarboxylic acid (TCA) cycle resulted in increased resistance of E. coli to PGRP killing. PGRP-induced killing depended on the production of hydrogen peroxide, which required increased supply of NADH for respiratory chain oxidoreductases from central carbon catabolism (glycolysis and TCA cycle), and was controlled by cAMP-Crp. Bactericidal PGRP induced a rapid decrease in respiration, which suggested that the main source of increased production of hydrogen peroxide was a block in respiratory chain and diversion of electrons from NADH oxidoreductases to oxygen. CpxRA two-component system was a negative regulator of PGRP-induced oxidative stress. By contrast, PGRP-induced thiol stress (depletion of thiols) and metal stress (increase in intracellular free Zn2+ through influx of extracellular Zn2+ ) were mostly independent of oxidative stress. Thus, manipulating pathways that induce oxidative, thiol and metal stress in bacteria could be a useful strategy to design new approaches to antibacterial therapy.
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Affiliation(s)
- Des R Kashyap
- Indiana University, School of Medicine-Northwest, Gary, IN, 46408, USA
| | - Marcin Kuzma
- Indiana University, School of Medicine-Northwest, Gary, IN, 46408, USA
| | | | - Dipika Gupta
- Indiana University, School of Medicine-Northwest, Gary, IN, 46408, USA
| | - Roman Dziarski
- Indiana University, School of Medicine-Northwest, Gary, IN, 46408, USA
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17
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McBee ME, Chionh YH, Sharaf ML, Ho P, Cai MWL, Dedon PC. Production of Superoxide in Bacteria Is Stress- and Cell State-Dependent: A Gating-Optimized Flow Cytometry Method that Minimizes ROS Measurement Artifacts with Fluorescent Dyes. Front Microbiol 2017; 8:459. [PMID: 28377755 PMCID: PMC5359317 DOI: 10.3389/fmicb.2017.00459] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 03/06/2017] [Indexed: 11/13/2022] Open
Abstract
The role of reactive oxygen species (ROS) in microbial metabolism and stress response has emerged as a major theme in microbiology and infectious disease. Reactive fluorescent dyes have the potential to advance the study of ROS in the complex intracellular environment, especially for high-content and high-throughput analyses. However, current dye-based approaches to measuring intracellular ROS have the potential for significant artifacts. Here, we describe a robust platform for flow cytometric quantification of ROS in bacteria using fluorescent dyes, with ROS measurements in 10s-of-1000s of individual cells under a variety of conditions. False positives and variability among sample types (e.g., bacterial species, stress conditions) are reduced with a flexible four-step gating scheme that accounts for side- and forward-scattered light (morphological changes), background fluorescence, DNA content, and dye uptake to identify cells producing ROS. Using CellROX Green dye with Escherichia coli, Mycobacterium smegmatis, and Mycobacterium bovis BCG as diverse model bacteria, we show that (1) the generation of a quantifiable CellROX Green signal for superoxide, but not hydrogen peroxide-induced hydroxyl radicals, validates this dye as a superoxide detector; (2) the level of dye-detectable superoxide does not correlate with cytotoxicity or antibiotic sensitivity; (3) the non-replicating, antibiotic tolerant state of nutrient-deprived mycobacteria is associated with high levels of superoxide; and (4) antibiotic-induced production of superoxide is idiosyncratic with regard to both the species and the physiological state of the bacteria. We also show that the gating method is applicable to other fluorescent indicator dyes, such as the 5-carboxyfluorescein diacetate acetoxymethyl ester and 5-cyano-2,3-ditolyl tetrazolium chloride for cellular esterase and reductive respiratory activities, respectively. These results demonstrate that properly controlled flow cytometry coupled with fluorescent probes provides precise and accurate quantitative analysis of ROS generation and metabolic changes in stressed bacteria.
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Affiliation(s)
- Megan E McBee
- Infectious Disease Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology Singapore, Singapore
| | - Yok H Chionh
- Infectious Disease Interdisciplinary Research Group, Singapore-MIT Alliance for Research and TechnologySingapore, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of SingaporeSingapore, Singapore
| | - Mariam L Sharaf
- Infectious Disease Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology Singapore, Singapore
| | - Peiying Ho
- Infectious Disease Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology Singapore, Singapore
| | - Maggie W L Cai
- Infectious Disease Interdisciplinary Research Group, Singapore-MIT Alliance for Research and TechnologySingapore, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of SingaporeSingapore, Singapore
| | - Peter C Dedon
- Infectious Disease Interdisciplinary Research Group, Singapore-MIT Alliance for Research and TechnologySingapore, Singapore; Department of Biological Engineering, Massachusetts Institute of Technology, CambridgeMA, USA
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18
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Cushnie TPT, O'Driscoll NH, Lamb AJ. Morphological and ultrastructural changes in bacterial cells as an indicator of antibacterial mechanism of action. Cell Mol Life Sci 2016; 73:4471-4492. [PMID: 27392605 PMCID: PMC11108400 DOI: 10.1007/s00018-016-2302-2] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 06/21/2016] [Accepted: 06/28/2016] [Indexed: 01/20/2023]
Abstract
Efforts to reduce the global burden of bacterial disease and contend with escalating bacterial resistance are spurring innovation in antibacterial drug and biocide development and related technologies such as photodynamic therapy and photochemical disinfection. Elucidation of the mechanism of action of these new agents and processes can greatly facilitate their development, but it is a complex endeavour. One strategy that has been popular for many years, and which is garnering increasing interest due to recent technological advances in microscopy and a deeper understanding of the molecular events involved, is the examination of treated bacteria for changes to their morphology and ultrastructure. In this review, we take a critical look at this approach. Variables affecting antibacterial-induced alterations are discussed first. These include characteristics of the test organism (e.g. cell wall structure) and incubation conditions (e.g. growth medium osmolarity). The main body of the review then describes the different alterations that can occur. Micrographs depicting these alterations are presented, together with information on agents that induce the change, and the sequence of molecular events that lead to the change. We close by highlighting those morphological and ultrastructural changes which are consistently induced by agents sharing the same mechanism (e.g. spheroplast formation by peptidoglycan synthesis inhibitors) and explaining how changes that are induced by multiple antibacterial classes (e.g. filamentation by DNA synthesis inhibitors, FtsZ disruptors, and other types of agent) can still yield useful mechanistic information. Lastly, recommendations are made regarding future study design and execution.
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Affiliation(s)
- T P Tim Cushnie
- Faculty of Medicine, Mahasarakham University, Khamriang, Kantarawichai, Maha Sarakham, 44150, Thailand.
| | - Noëlle H O'Driscoll
- School of Pharmacy and Life Sciences, Robert Gordon University, Sir Ian Wood Building, Garthdee Road, Aberdeen, AB10 7GJ, UK
| | - Andrew J Lamb
- School of Pharmacy and Life Sciences, Robert Gordon University, Sir Ian Wood Building, Garthdee Road, Aberdeen, AB10 7GJ, UK
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19
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Trimble MJ, Mlynárčik P, Kolář M, Hancock REW. Polymyxin: Alternative Mechanisms of Action and Resistance. Cold Spring Harb Perspect Med 2016; 6:cshperspect.a025288. [PMID: 27503996 DOI: 10.1101/cshperspect.a025288] [Citation(s) in RCA: 243] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Antibiotic resistance among pathogenic bacteria is an ever-increasing issue worldwide. Unfortunately, very little has been achieved in the pharmaceutical industry to combat this problem. This has led researchers and the medical field to revisit past drugs that were deemed too toxic for clinical use. In particular, the cyclic cationic peptides polymyxin B and colistin, which are specific for Gram-negative bacteria, have been used as "last resort" antimicrobials. Before the 1980s, these drugs were known for their renal and neural toxicities; however, new clinical practices and possibly improved manufacturing have made them safer to use. Previously suggested to primarily attack the membranes of Gram-negative bacteria and to not easily select for resistant mutants, recent research exploring resistance and mechanisms of action has provided new perspectives. This review focuses primarily on the proposed alternative mechanisms of action, known resistance mechanisms, and how these support the alternative mechanisms of action.
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Affiliation(s)
- Michael J Trimble
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Patrik Mlynárčik
- Department of Microbiology, Faculty of Medicine and Dentistry, Palacký University, 771 47 Olomouc, Czech Republic
| | - Milan Kolář
- Department of Microbiology, Faculty of Medicine and Dentistry, Palacký University, 771 47 Olomouc, Czech Republic
| | - Robert E W Hancock
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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20
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Reactive oxygen species do not contribute to ObgE*-mediated programmed cell death. Sci Rep 2016; 6:33723. [PMID: 27641546 PMCID: PMC5027388 DOI: 10.1038/srep33723] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 09/01/2016] [Indexed: 11/09/2022] Open
Abstract
Programmed cell death (PCD) in bacteria is considered an important target for developing novel antimicrobials. Development of PCD-specific therapies requires a deeper understanding of what drives this process. We recently discovered a new mode of PCD in Escherichia coli that is triggered by expression of a mutant isoform of the essential ObgE protein, ObgE*. Our previous findings demonstrate that ObgE*-mediated cell death shares key characteristics with apoptosis in eukaryotic cells. It is well-known that reactive oxygen species (ROS) are formed during PCD in eukaryotes and play a pivotal role as signaling molecules in the progression of apoptosis. Therefore, we explored a possible role for ROS in bacterial killing by ObgE*. Using fluorescent probes and genetic reporters, we found that expression of ObgE* induces formation of ROS. Neutralizing ROS by chemical scavenging or by overproduction of ROS-neutralizing enzymes did not influence toxicity of ObgE*. Moreover, expression of ObgE* under anaerobic conditions proved to be as detrimental to bacterial viability as expression under aerobic conditions. In conclusion, ROS are byproducts of ObgE* expression that do not play a role in the execution or progression of ObgE*-mediated PCD. Targeted therapies should therefore look to exploit other aspects of ObgE*-mediated PCD.
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21
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Van Acker H, Gielis J, Acke M, Cools F, Cos P, Coenye T. The Role of Reactive Oxygen Species in Antibiotic-Induced Cell Death in Burkholderia cepacia Complex Bacteria. PLoS One 2016; 11:e0159837. [PMID: 27438061 PMCID: PMC4954720 DOI: 10.1371/journal.pone.0159837] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 07/08/2016] [Indexed: 11/19/2022] Open
Abstract
It was recently proposed that bactericidal antibiotics, besides through specific drug-target interactions, kill bacteria by a common mechanism involving the production of reactive oxygen species (ROS). However, this mechanism involving the production of hydroxyl radicals has become the subject of a lot of debate. Since the contribution of ROS to antibiotic mediated killing most likely depends on the conditions, differences in experimental procedures are expected to be at the basis of the conflicting results. In the present study different methods (ROS specific stainings, gene-expression analyses, electron paramagnetic resonance, genetic and phenotypic experiments, detection of protein carbonylation and DNA oxidation) to measure the production of ROS upon antibiotic treatment in Burkholderia cepacia complex (Bcc) bacteria were compared. Different classes of antibiotics (tobramycin, ciprofloxacin, meropenem) were included, and both planktonic and biofilm cultures were studied. Our results indicate that some of the methods investigated were not sensitive enough to measure antibiotic induced production of ROS, including the spectrophotometric detection of protein carbonylation. Secondly, other methods were found to be useful only in specific conditions. For example, an increase in the expression of OxyR was measured in Burkholderia cenocepacia K56-2 after treatment with ciprofloxacin or meropenem (both in biofilms and planktonic cultures) but not after treatment with tobramycin. In addition results vary with the experimental conditions and the species tested. Nevertheless our data strongly suggest that ROS contribute to antibiotic mediated killing in Bcc species and that enhancing ROS production or interfering with the protection against ROS may form a novel strategy to improve antibiotic treatment.
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Affiliation(s)
- Heleen Van Acker
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Jan Gielis
- Department of Thoracic Surgery, Antwerp Surgical Training and Anatomy Research Centre (ASTARC), Antwerp University, Antwerp, Belgium
- Laboratory for Microbiology, Parasitology and Hygiene, University of Antwerp, Antwerp, Belgium
| | - Marloes Acke
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Freya Cools
- Laboratory for Microbiology, Parasitology and Hygiene, University of Antwerp, Antwerp, Belgium
| | - Paul Cos
- Laboratory for Microbiology, Parasitology and Hygiene, University of Antwerp, Antwerp, Belgium
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
- * E-mail:
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22
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Fumarate-Mediated Persistence of Escherichia coli against Antibiotics. Antimicrob Agents Chemother 2016; 60:2232-40. [PMID: 26810657 DOI: 10.1128/aac.01794-15] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 01/21/2016] [Indexed: 11/20/2022] Open
Abstract
Bacterial persisters are a small fraction of quiescent cells that survive in the presence of lethal concentrations of antibiotics. They can regrow to give rise to a new population that has the same vulnerability to the antibiotics as did the parental population. Although formation of bacterial persisters in the presence of various antibiotics has been documented, the molecular mechanisms by which these persisters tolerate the antibiotics are still controversial. We found that amplification of the fumarate reductase operon (FRD) inEscherichia coliled to a higher frequency of persister formation. The persister frequency ofE. coliwas increased when the cells contained elevated levels of intracellular fumarate. Genetic perturbations of the electron transport chain (ETC), a metabolite supplementation assay, and even the toxin-antitoxin-relatedhipA7mutation indicated that surplus fumarate markedly elevated theE. colipersister frequency. AnE. colistrain lacking succinate dehydrogenase (SDH), thereby showing a lower intracellular fumarate concentration, was killed ∼1,000-fold more effectively than the wild-type strain in the stationary phase. It appears thatSDHandFRDrepresent a paired system that gives rise to and maintainsE. colipersisters by producing and utilizing fumarate, respectively.
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23
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Belenky P, Ye JD, Porter CBM, Cohen NR, Lobritz MA, Ferrante T, Jain S, Korry BJ, Schwarz EG, Walker GC, Collins JJ. Bactericidal Antibiotics Induce Toxic Metabolic Perturbations that Lead to Cellular Damage. Cell Rep 2015; 13:968-80. [PMID: 26565910 DOI: 10.1016/j.celrep.2015.09.059] [Citation(s) in RCA: 320] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 09/04/2015] [Accepted: 09/17/2015] [Indexed: 01/16/2023] Open
Abstract
Understanding how antibiotics impact bacterial metabolism may provide insight into their mechanisms of action and could lead to enhanced therapeutic methodologies. Here, we profiled the metabolome of Escherichia coli after treatment with three different classes of bactericidal antibiotics (?-lactams, aminoglycosides, quinolones). These treatments induced a similar set of metabolic changes after 30 min that then diverged into more distinct profiles at later time points. The most striking changes corresponded to elevated concentrations of central carbon metabolites, active breakdown of the nucleotide pool, reduced lipid levels, and evidence of an elevated redox state. We examined potential end-target consequences of these metabolic perturbations and found that antibiotic-treated cells exhibited cytotoxic changes indicative of oxidative stress, including higher levels of protein carbonylation, malondialdehyde adducts, nucleotide oxidation, and double-strand DNA breaks. This work shows that bactericidal antibiotics induce a complex set of metabolic changes that are correlated with the buildup of toxic metabolic by-products.
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Affiliation(s)
- Peter Belenky
- Department of Biomedical Engineering and Center of Synthetic Biology, Boston University, 36 Cummington Mall, Boston, MA 02215, USA; Department of Molecular Microbiology and Immunology, Brown University, 171 Meeting Street, Providence, RI 02912, USA.
| | - Jonathan D Ye
- Department of Biomedical Engineering and Center of Synthetic Biology, Boston University, 36 Cummington Mall, Boston, MA 02215, USA
| | - Caroline B M Porter
- Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, Boston, MA 02115, USA
| | - Nadia R Cohen
- Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, Boston, MA 02115, USA
| | - Michael A Lobritz
- Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, Boston, MA 02115, USA; Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA 02115, USA
| | - Thomas Ferrante
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, Boston, MA 02115, USA
| | - Saloni Jain
- Department of Biomedical Engineering and Center of Synthetic Biology, Boston University, 36 Cummington Mall, Boston, MA 02215, USA; Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Benjamin J Korry
- Department of Molecular Microbiology and Immunology, Brown University, 171 Meeting Street, Providence, RI 02912, USA
| | - Eric G Schwarz
- Department of Biomedical Engineering and Center of Synthetic Biology, Boston University, 36 Cummington Mall, Boston, MA 02215, USA
| | - Graham C Walker
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - James J Collins
- Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, Boston, MA 02115, USA.
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24
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Catalase Expression Is Modulated by Vancomycin and Ciprofloxacin and Influences the Formation of Free Radicals in Staphylococcus aureus Cultures. Appl Environ Microbiol 2015; 81:6393-8. [PMID: 26150471 DOI: 10.1128/aem.01199-15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Accepted: 07/02/2015] [Indexed: 12/24/2022] Open
Abstract
Detection of free radicals in biological systems is challenging due to their short half-lives. We have applied electron spin resonance (ESR) spectroscopy combined with spin traps using the probes PBN (N-tert-butyl-α-phenylnitrone) and DMPO (5,5-dimethyl-1-pyrroline N-oxide) to assess free radical formation in the human pathogen Staphylococcus aureus treated with a bactericidal antibiotic, vancomycin or ciprofloxacin. While we were unable to detect ESR signals in bacterial cells, hydroxyl radicals were observed in the supernatant of bacterial cell cultures. Surprisingly, the strongest signal was detected in broth medium without bacterial cells present and it was mitigated by iron chelation or by addition of catalase, which catalyzes the decomposition of hydrogen peroxide to water and oxygen. This suggests that the signal originates from hydroxyl radicals formed by the Fenton reaction, in which iron is oxidized by hydrogen peroxide. Previously, hydroxyl radicals have been proposed to be generated within bacterial cells in response to bactericidal antibiotics. We found that when S. aureus was exposed to vancomycin or ciprofloxacin, hydroxyl radical formation in the broth was indeed increased compared to the level seen with untreated bacterial cells. However, S. aureus cells express catalase, and the antibiotic-mediated increase in hydroxyl radical formation was correlated with reduced katA expression and catalase activity in the presence of either antibiotic. Therefore, our results show that in S. aureus, bactericidal antibiotics modulate catalase expression, which in turn influences the formation of free radicals in the surrounding broth medium. If similar regulation is found in other bacterial species, it might explain why bactericidal antibiotics are perceived as inducing formation of free radicals.
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25
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Thakur A, Alam MJ, Ajayakumar MR, Ghaskadbi S, Sharma M, Goswami SK. Norepinephrine-induced apoptotic and hypertrophic responses in H9c2 cardiac myoblasts are characterized by different repertoire of reactive oxygen species generation. Redox Biol 2015; 5:243-252. [PMID: 26070033 PMCID: PMC4477046 DOI: 10.1016/j.redox.2015.05.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 05/26/2015] [Indexed: 01/04/2023] Open
Abstract
Despite recent advances, the role of ROS in mediating hypertrophic and apoptotic responses in cardiac myocytes elicited by norepinephrine (NE) is rather poorly understood. We demonstrate through our experiments that H9c2 cardiac myoblasts treated with 2 µM NE (hypertrophic dose) generate DCFH-DA positive ROS only for 2 h; while those treated with 100 µM NE (apoptotic dose) sustains generation for 48 h, followed by apoptosis. Though the levels of DCFH fluorescence were comparable at early time points in the two treatment sets, its quenching by DPI, catalase and MnTmPyP suggested the existence of a different repertoire of ROS. Both doses of NE also induced moderate levels of H2O2 but with different kinetics. Sustained but intermittent generation of highly reactive species detectable by HPF was seen in both treatment sets but no peroxynitrite was generated in either conditions. Sustained generation of hydroxyl radicals with no appreciable differences were noticed in both treatment sets. Nevertheless, despite similar profile of ROS generation between the two conditions, extensive DNA damage as evident from the increase in 8-OH-dG content, formation of γ-H2AX and PARP cleavage was seen only in cells treated with the higher dose of NE. We therefore conclude that hypertrophic and apoptotic doses of NE generate distinct but comparable repertoire of ROS/RNS leading to two very distinct downstream responses. H9c2 myoblasts upon treatment with 2 and 100 µM NE induces hypertrophy and apoptosis. Both treatments show comparable levels of DCFH fluorescence with different kinetics. Both treatments show comparable levels of HPF fluorescence in an oscillating manner. More hydroxyl radical was generated in 100 µM NE treated set. DNA damage and apoptosis occurs only in 100 µM NE treated sets.
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Affiliation(s)
- Anita Thakur
- Department of Biology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Md Jahangir Alam
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - M R Ajayakumar
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | | | - Manish Sharma
- Defence Institute of Physiology & Allied Sciences, New Delhi 110054, India
| | - Shyamal K Goswami
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
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26
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Kjeldsen TSB, Sommer MOA, Olsen JE. Extended spectrum β-lactamase-producing Escherichia coli forms filaments as an initial response to cefotaxime treatment. BMC Microbiol 2015; 15:63. [PMID: 25888392 PMCID: PMC4367913 DOI: 10.1186/s12866-015-0399-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 02/24/2015] [Indexed: 11/10/2022] Open
Abstract
Background β-lactams target the peptidoglycan layer in the bacterial cell wall and most β-lactam antibiotics cause filamentation in susceptible Gram-negative bacteria at low concentrations. The objective was to determine the initial morphological response of cephalosporin resistant CTX-M-1-producing E. coli to cefotaxime and to determine whether the response depended on the growth phase of the bacterium and the concentration of antibiotic. Results Two antibiotic resistant strains carrying blaCTX-M-1 on the chromosome and on an IncI1 plasmid and three sensitive strains were used in this study. The resistant strains displayed elongated cells when exposed to cefotaxime at sub-inhibitory as well as therapeutic concentrations (1 to 512 mg/L of cefotaxime) in both lag and early exponential phase, suggesting that the elongation was an initial response mechanism to the antibiotic. Normal sized cells were the dominant cell type in exponential and stationary growth phase. No elongated cells were seen in cultures without cefotaxime. In cultures with high concentrations of cefotaxime (128–512 mg/L), no growth other than initial filamentation was observed, but spheroplats appeared after 14–17 hours in cultures of the resistant strains. Filaments were also observed in sensitive control strains with sub-inhibitory concentrations of cefotaxime. Conclusions We showed that E. coli resistant to β-lactams by an extended-spectrum β-lactamase, blaCTX-M-1, produced filaments when exposed to cefotaxime. The filament formation was restricted to early growth phases and the time the cells grew as filaments was antibiotic concentration dependent. This indicates that antibiotic resistant E. coli undergo the same morphological changes as sensitive bacteria in the presence of β-lactam antibiotic. It was showed that the filament formation was an initial response to the antibiotics.
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Affiliation(s)
- Thea S B Kjeldsen
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, 1870, Frederiksberg C, Denmark.
| | - Morten O A Sommer
- Department of Systems Biology, Technical University of Denmark, 2800, Lyngby, Denmark. .,Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2970, Hørsholm, Denmark.
| | - John E Olsen
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, 1870, Frederiksberg C, Denmark.
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Diagnosing oxidative stress in bacteria: not as easy as you might think. Curr Opin Microbiol 2015; 24:124-31. [PMID: 25666086 DOI: 10.1016/j.mib.2015.01.004] [Citation(s) in RCA: 159] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 12/31/2014] [Accepted: 01/08/2015] [Indexed: 12/31/2022]
Abstract
Microorganisms are vulnerable to elevated levels of intracellular reactive oxygen species (ROS). This situation has led to proposals that many natural stresses might be toxic specifically because they accelerate endogenous ROS formation. Such a mechanism has been convincingly demonstrated for redox-cycling compounds. However, the evidence is much weaker for most other stressors. The hypothesis that clinical antibiotics generate lethal ROS stress has attracted much attention, and the author discusses some aspects of evidence that support or oppose this idea. Importantly, even if all cellular electron flow were somehow diverted to ROS formation, the resultant doses of H2O2 and O2(-) would more likely be bacteriostatic than bacteriocidal unless key defense mechanisms were simultaneously blocked.
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Sigma S-dependent antioxidant defense protects stationary-phase Escherichia coli against the bactericidal antibiotic gentamicin. Antimicrob Agents Chemother 2014; 58:5964-75. [PMID: 25070093 DOI: 10.1128/aac.03683-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Stationary-phase bacteria are important in disease. The σ(s)-regulated general stress response helps them become resistant to disinfectants, but the role of σ(s) in bacterial antibiotic resistance has not been elucidated. Loss of σ(s) rendered stationary-phase Escherichia coli more sensitive to the bactericidal antibiotic gentamicin (Gm), and proteomic analysis suggested involvement of a weakened antioxidant defense. Use of the psfiA genetic reporter, 3'-(p-hydroxyphenyl) fluorescein (HPF) dye, and Amplex Red showed that Gm generated more reactive oxygen species (ROS) in the mutant. HPF measurements can be distorted by cell elongation, but Gm did not affect stationary-phase cell dimensions. Coadministration of the antioxidant N-acetyl cysteine (NAC) decreased drug lethality particularly in the mutant, as did Gm treatment under anaerobic conditions that prevent ROS formation. Greater oxidative stress, due to insufficient quenching of endogenous ROS and/or respiration-linked electron leakage, therefore contributed to the greater sensitivity of the mutant; infection by a uropathogenic strain in mice showed this to be the case also in vivo. Disruption of antioxidant defense by eliminating the quencher proteins, SodA/SodB and KatE/SodA, or the pentose phosphate pathway proteins, Zwf/Gnd and TalA, which provide NADPH for ROS decomposition, also generated greater oxidative stress and killing by Gm. Thus, besides its established mode of action, Gm also kills stationary-phase bacteria by generating oxidative stress, and targeting the antioxidant defense of E. coli can enhance its efficacy. Relevant aspects of the current controversy on the role of ROS in killing by bactericidal drugs of exponential-phase bacteria, which represent a different physiological state, are discussed.
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