1
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Klenotic PA, Yu EW. Structural analysis of resistance-nodulation cell division transporters. Microbiol Mol Biol Rev 2024; 88:e0019823. [PMID: 38551344 DOI: 10.1128/mmbr.00198-23] [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] [Indexed: 06/28/2024] Open
Abstract
SUMMARYInfectious bacteria have both intrinsic and acquired mechanisms to combat harmful biocides that enter the cell. Through adaptive pressures, many of these pathogens have become resistant to many, if not all, of the current antibiotics used today to treat these often deadly infections. One prominent mechanism is the upregulation of efflux systems, especially the resistance-nodulation-cell division class of exporters. These tripartite systems consist of an inner membrane transporter coupled with a periplasmic adaptor protein and an outer membrane channel to efficiently transport a diverse array of substrates from inside the cell to the extracellular space. Detailed mechanistic insight into how these inner membrane transporters recognize and shuttle their substrates can ultimately inform both new antibiotic and efflux pump inhibitor design. This review examines the structural basis of substrate recognition of these pumps and the molecular mechanisms underlying multidrug extrusion, which in turn mediate antimicrobial resistance in bacterial pathogens.
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Affiliation(s)
- Philip A Klenotic
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Edward W Yu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
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2
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Allamyradov Y, Yosef JB, Kylychbekov S, Majidov I, Khuzhakulov Z, Er AY, Kitchens C, Banga S, Er AO. The role of efflux pump inhibitor in enhancing antimicrobial efficiency of Ag NPs and MB as an effective photodynamic therapy agent. Photodiagnosis Photodyn Ther 2024; 47:104212. [PMID: 38740317 DOI: 10.1016/j.pdpdt.2024.104212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/19/2024] [Accepted: 05/08/2024] [Indexed: 05/16/2024]
Abstract
Efflux pumps are active transporters, which allow the cell to remove toxic substances from within the cell including antibiotics and photosensitizer complexes. Efflux pump inhibitors (EPIs), chemicals that prevent the passage of molecules through efflux pumps, play a crucial role in antimicrobial effectiveness against pathogen. In this work, we studied the effect of EPI, namely, reserpine, on photodeactivation rate of pathogens when used with Ag NPs and methylene blue (MB). Our results show that using reserpine led to a higher deactivation rate than Ag NPs and MB alone. The mechanism of this observation was investigated with singlet oxygen generation amount. Additionally, different sizes of Ag NPs were tested with reserpine. Molecular docking calculation shows that reserpine had higher affinity toward AcrB than MB. The improvement in bacterial deactivation rate is attributed to blockage of the AcrAB-TolC efflux pump preventing the removal of MB rather than enhanced singlet oxygen production. These results suggest that using reserpine with nanoparticles and photosynthesize is a promising approach in photodynamic therapy.
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Affiliation(s)
- Yaran Allamyradov
- Department of Physics & Astronomy, Western Kentucky University, Bowling Green, KY 42101, USA
| | - Justice Ben Yosef
- Department of Chemistry, Western Kentucky University, Bowling Green, KY 42101, USA
| | - Salizhan Kylychbekov
- Department of Physics & Astronomy, Western Kentucky University, Bowling Green, KY 42101, USA
| | - Inomjon Majidov
- Department of Physics & Astronomy, Western Kentucky University, Bowling Green, KY 42101, USA
| | - Zikrulloh Khuzhakulov
- Department of Physics & Astronomy, Western Kentucky University, Bowling Green, KY 42101, USA
| | - Alper Yusuf Er
- Gatton Academy of Mathematics and Science, Western Kentucky University, Bowling Green, KY 42101, USA
| | - Chazz Kitchens
- Department of Biology, Western Kentucky University, Bowling Green, KY 42101, USA
| | - Simran Banga
- Department of Biology, Western Kentucky University, Bowling Green, KY 42101, USA
| | - Ali Oguz Er
- Department of Physics & Astronomy, Western Kentucky University, Bowling Green, KY 42101, USA.
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3
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Saini P, Bandsode V, Singh A, Mendem SK, Semmler T, Alam M, Ahmed N. Genomic insights into virulence, antimicrobial resistance, and adaptation acumen of Escherichia coli isolated from an urban environment. mBio 2024; 15:e0354523. [PMID: 38376265 PMCID: PMC10936179 DOI: 10.1128/mbio.03545-23] [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: 01/11/2024] [Accepted: 01/23/2024] [Indexed: 02/21/2024] Open
Abstract
Populations of common commensal bacteria such as Escherichia coli undergo genetic changes by the acquisition of certain virulence and antimicrobial resistance (AMR) encoding genetic elements leading to the emergence of pathogenic strains capable of surviving in the previously uninhabited or protected niches. These bacteria are also reported to be prevalent in the environment where they survive by adopting various recombination strategies to counter microflora of the soil and water, under constant selection pressure(s). In this study, we performed molecular characterization, phenotypic AMR analysis, and whole genome sequencing (WGS) of E. coli (n = 37) isolated from soil and surface water representing the urban and peri-urban areas. The primary aim of this study was to understand the genetic architecture and pathogenic acumen exhibited by environmental E. coli. WGS-based analysis entailing resistome and virulome profiling indicated the presence of various virulence (adherence, iron uptake, and toxins) and AMR encoding genes, including blaNDM-5 in the environmental isolates. A majority of our isolates belonged to phylogroup B1 (73%). A few isolates in our collection were of sequence type(s) (ST) 58 and 224 that could have emerged recently as clonal lineages and might pose risk of infection/transmission. Mobile genetic elements (MGEs) such as plasmids (predominantly) of the IncF family, prophages, pipolins, and insertion elements such as IS1 and IS5 were also observed to exist, which may presumably aid in the propagation of genes encoding resistance against antimicrobial drugs. The observed high prevalence of MGEs associated with multidrug resistance in pathogenic E. coli isolates belonging to the phylogroup B1 underscores the need for extended surveillance to keep track of and prevent the transmission of the bacterium to certain vulnerable human and animal populations. IMPORTANCE Evolutionary patterns of E. coli bacteria convey that they evolve into highly pathogenic forms by acquiring fitness advantages, such as AMR, and various virulence factors through the horizontal gene transfer (HGT)-mediated acquisition of MGEs. However, limited research on the genetic profiles of environmental E. coli, particularly from India, hinders our understanding of their transition to pathogenic forms and impedes the adoption of a comprehensive approach to address the connection between environmentally dwelling E. coli populations and human and veterinary public health. This study focuses on high-resolution genomic analysis of the environmental E. coli isolates aiming to understand the genetic similarities and differences among isolates from different environmental niches and uncover the survival strategies employed by these bacteria to thrive in their surroundings. Our approach involved molecular characterization of environmental samples using PCR-based DNA fingerprinting and subsequent WGS analysis. This multidisciplinary approach is likely to provide valuable insights into the understanding of any potential spill-over to human and animal populations and locales. Investigating these environmental isolates has significant potential for developing epidemiological strategies against transmission and understanding niche-specific evolutionary patterns.
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Affiliation(s)
- Poorvi Saini
- Department of Biotechnology and Bioinformatics, Pathogen Biology Laboratory, University of Hyderabad, Hyderabad, Telangana State, India
| | - Viraj Bandsode
- Department of Biotechnology and Bioinformatics, Pathogen Biology Laboratory, University of Hyderabad, Hyderabad, Telangana State, India
| | - Anuradha Singh
- Department of Biotechnology and Bioinformatics, Pathogen Biology Laboratory, University of Hyderabad, Hyderabad, Telangana State, India
| | - Suresh Kumar Mendem
- Department of Biotechnology and Bioinformatics, Pathogen Biology Laboratory, University of Hyderabad, Hyderabad, Telangana State, India
| | | | - Munirul Alam
- International Centre for Diarrheal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Niyaz Ahmed
- Department of Biotechnology and Bioinformatics, Pathogen Biology Laboratory, University of Hyderabad, Hyderabad, Telangana State, India
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Schuster S, Vavra M, Wirth DAN, Kern WV. Comparative reassessment of AcrB efflux inhibitors reveals differential impact of specific pump mutations on the activity of potent compounds. Microbiol Spectr 2024; 12:e0304523. [PMID: 38170977 PMCID: PMC10846202 DOI: 10.1128/spectrum.03045-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 11/17/2023] [Indexed: 01/05/2024] Open
Abstract
Multidrug resistance poses global challenges, particularly with regard to Gram-negative bacterial infections. In view of the lack of new antibiotics, drug enhancers, such as efflux pump inhibitors (EPIs), have increasingly come into focus. A number of chemically diverse agents have been reported to inhibit AcrB, the main multidrug transporter in Escherichia coli, and homologs in other Gram-negative bacteria. However, due to the often varying methodologies used for their characterization, results remain difficult to compare. In this study, using a defined selection of antibiotics known to be efflux substrates, we reevaluated 38 published compounds for their in vitro EPI activity. When examined in an E. coli strain with stable wild-type AcrB overexpression, we found 17 compounds showing at least fourfold enhancing potency with more than 2 out of 10 test drugs (belonging to eight antibiotic classes). Pyranopyridines (MBX series) were confirmed as the most potent inhibitors among agents reported so far. A new and surprising finding was that their activity, unlike that of the pyridylpiperazine EPI BDM88855, was highly susceptible to the AcrB double-mutation G141D_N282Y, which had previously been shown to diminish drug enhancing of 1-(1-naphthylmethyl)piperazine in a predominantly substrate-specific manner. Conversely, transmembrane region mutation V411A, while eliminating the drug potentiating of the BDM compound, did not decrease the activity of the MBX EPIs. Besides comparative reassessment of the potency of reported EPIs, the study demonstrated the usefulness of mutagenesis approaches providing tools for an initial discrimination of EPIs regarding their mode of function.IMPORTANCEInfections with difficult-to-treat multidrug-resistant bacteria pose an urgent global threat in view of the stagnating development of new antimicrobial substances. Efflux pumps in Gram-negative pathogens are known to substantially contribute to multidrug resistance making them promising targets for chemotherapeutic interventions to restore the efficacy of conventional antibiotics. In the present study, the in vitro activity of previously reported efflux pump inhibitors was reassessed using standardized conditions. Relevant drug sensitizing activity could be proven for almost half of the tested compounds. Further characterization of potent inhibitors was achieved by investigating the impact of specific efflux pump mutations. A double-mutation previously known to decrease the activity of the arylpiperazine 1-(1-naphthylmethyl)piperazine also impaired that of the highly efficient pyranopyridine efflux pump inhibitors. Our findings provide direct comparability of reported efflux pump inhibitors and contribute to the elucidation of their mode of action.
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Affiliation(s)
- Sabine Schuster
- Division of Infectious Diseases, Department of Medicine II, University Hospital and Medical Center, Freiburg, Germany
| | - Martina Vavra
- Division of Infectious Diseases, Department of Medicine II, University Hospital and Medical Center, Freiburg, Germany
| | - Dave A. N. Wirth
- Division of Infectious Diseases, Department of Medicine II, University Hospital and Medical Center, Freiburg, Germany
| | - Winfried V. Kern
- Division of Infectious Diseases, Department of Medicine II, University Hospital and Medical Center, Freiburg, Germany
- Faculty of Medicine, Albert-Ludwigs University, Freiburg, Germany
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5
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Wilhelm J, Pos KM. Molecular insights into the determinants of substrate specificity and efflux inhibition of the RND efflux pumps AcrB and AdeB. MICROBIOLOGY (READING, ENGLAND) 2024; 170:001438. [PMID: 38358391 PMCID: PMC10924465 DOI: 10.1099/mic.0.001438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/30/2024] [Indexed: 02/16/2024]
Abstract
Gram-negative bacterial members of the Resistance Nodulation and cell Division (RND) superfamily form tripartite efflux pump systems that span the cell envelope. One of the intriguing features of the multiple drug efflux members of this superfamily is their ability to recognize different classes of antibiotics, dyes, solvents, bile salts, and detergents. This review provides an overview of the molecular mechanisms of multiple drug efflux catalysed by the tripartite RND efflux system AcrAB-TolC from Eschericha coli. The determinants for sequential or simultaneous multiple substrate binding and efflux pump inhibitor binding are discussed. A comparison is made with the determinants for substrate binding of AdeB from Acinetobacter baumannii, which acts within the AdeABC multidrug efflux system. There is an apparent general similarity between the structures of AcrB and AdeB and their substrate specificity. However, the presence of distinct conformational states and different drug efflux capacities as revealed by single-particle cryo-EM and mutational analysis suggest that the drug binding and transport features exhibited by AcrB may not be directly extrapolated to the homolog AdeB efflux pump.
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Affiliation(s)
- Julia Wilhelm
- Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany
| | - Klaas Martinus Pos
- Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany
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6
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Xu L, Liaqat F, Sun J, Khazi MI, Xie R, Zhu D. Advances in the vanillin synthesis and biotransformation: A review. RENEWABLE AND SUSTAINABLE ENERGY REVIEWS 2024; 189:113905. [DOI: 10.1016/j.rser.2023.113905] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/23/2024]
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7
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Pisoni LA, Semple SJ, Liu S, Sykes MJ, Venter H. Combined Structure- and Ligand-Based Approach for the Identification of Inhibitors of AcrAB-TolC in Escherichia coli. ACS Infect Dis 2023; 9:2504-2522. [PMID: 37888944 DOI: 10.1021/acsinfecdis.3c00350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
The inhibition of efflux pumps is a promising approach to combating multidrug-resistant bacteria. We have developed a combined structure- and ligand-based model, using OpenEye software, for the identification of inhibitors of AcrB, the inner membrane protein component of the AcrAB-TolC efflux pump in Escherichia coli. From a database of 1391 FDA-approved drugs, 23 compounds were selected to test for efflux inhibition in E. coli. Seven compounds, including ivacaftor (25), butenafine (19), naftifine (27), pimozide (30), thioridazine (35), trifluoperazine (37), and meloxicam (26), enhanced the activity of at least one antimicrobial substrate and inhibited the efflux pump-mediated removal of the substrate Nile Red from cells. Ivacaftor (25) inhibited efflux dose dependently, had no effect on an E. coli strain with genomic deletion of the gene encoding AcrB, and did not damage the bacterial outer membrane. In the presence of a sub-minimum inhibitory concentration (MIC) of the outer membrane permeabilizer colistin, ivacaftor at 1 μg/mL reduced the MICs of erythromycin and minocycline by 4- to 8-fold. The identification of seven potential AcrB inhibitors shows the merits of a combined structure- and ligand-based approach to virtual screening.
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Affiliation(s)
- Lily A Pisoni
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, South Australia 5000, Australia
- Quality Use of Medicines and Pharmacy Research Centre, Clinical and Health Sciences, University of South Australia, Adelaide, South Australia 5000, Australia
| | - Susan J Semple
- Quality Use of Medicines and Pharmacy Research Centre, Clinical and Health Sciences, University of South Australia, Adelaide, South Australia 5000, Australia
| | - Sida Liu
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, South Australia 5000, Australia
| | - Matthew J Sykes
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, South Australia 5000, Australia
| | - Henrietta Venter
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, South Australia 5000, Australia
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8
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Wallace VJ, Sakowski EG, Preheim SP, Prasse C. Bacteria exposed to antiviral drugs develop antibiotic cross-resistance and unique resistance profiles. Commun Biol 2023; 6:837. [PMID: 37573457 PMCID: PMC10423222 DOI: 10.1038/s42003-023-05177-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 07/25/2023] [Indexed: 08/14/2023] Open
Abstract
Antiviral drugs are used globally as treatment and prophylaxis for long-term and acute viral infections. Even though antivirals also have been shown to have off-target effects on bacterial growth, the potential contributions of antivirals to antimicrobial resistance remains unknown. Herein we explored the ability of different classes of antiviral drugs to induce antimicrobial resistance. Our results establish the previously unrecognized capacity of antivirals to broadly alter the phenotypic antimicrobial resistance profiles of both gram-negative and gram-positive bacteria Escherichia coli and Bacillus cereus. Bacteria exposed to antivirals including zidovudine, dolutegravir and raltegravir developed cross-resistance to commonly used antibiotics including trimethoprim, tetracycline, clarithromycin, erythromycin, and amoxicillin. Whole genome sequencing of antiviral-resistant E. coli isolates revealed numerous unique single base pair mutations, as well as multi-base pair insertions and deletions, in genes with known and suspected roles in antimicrobial resistance including those coding for multidrug efflux pumps, carbohydrate transport, and cellular metabolism. The observed phenotypic changes coupled with genotypic results indicate that bacteria exposed to antiviral drugs with antibacterial properties in vitro can develop multiple resistance mutations that confer cross-resistance to antibiotics. Our findings underscore the potential contribution of wide scale usage of antiviral drugs to the development and spread of antimicrobial resistance in humans and the environment.
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Affiliation(s)
- Veronica J Wallace
- Department of Environmental Health and Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Eric G Sakowski
- Department of Environmental Health and Engineering, Johns Hopkins University, Baltimore, MD, USA
- Department of Science, Mount St. Mary's University, Emmitsburg, MD, USA
| | - Sarah P Preheim
- Department of Environmental Health and Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Carsten Prasse
- Department of Environmental Health and Engineering, Johns Hopkins University, Baltimore, MD, USA.
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9
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Cha S, Cho YJ, Lee JK, Hahn JS. Regulation of acetate tolerance by small ORF-encoded polypeptides modulating efflux pump specificity in Methylomonas sp. DH-1. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:114. [PMID: 37464261 DOI: 10.1186/s13068-023-02364-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 07/02/2023] [Indexed: 07/20/2023]
Abstract
BACKGROUND Methanotrophs have emerged as promising hosts for the biological conversion of methane into value-added chemicals, including various organic acids. Understanding the mechanisms of acid tolerance is essential for improving organic acid production. WatR, a LysR-type transcriptional regulator, was initially identified as involved in lactate tolerance in a methanotrophic bacterium Methylomonas sp. DH-1. In this study, we investigated the role of WatR as a regulator of cellular defense against weak organic acids and identified novel target genes of WatR. RESULTS By conducting an investigation into the genome-wide binding targets of WatR and its role in transcriptional regulation, we identified genes encoding an RND-type efflux pump (WatABO pump) and previously unannotated small open reading frames (smORFs), watS1 to watS5, as WatR target genes activated in response to acetate. The watS1 to watS5 genes encode polypeptides of approximately 50 amino acids, and WatS1 to WatS4 are highly homologous with one predicted transmembrane domain. Deletion of the WatABO pump genes resulted in decreased tolerance against formate, acetate, lactate, and propionate, suggesting its role as an efflux pump for a wide range of weak organic acids. WatR repressed the basal expression of watS genes but activated watS and WatABO pump genes in response to acetate stress. Overexpression of watS1 increased tolerance to acetate but not to other acids, only in the presence of the WatABO pump. Therefore, WatS1 may increase WatABO pump specificity toward acetate, switching the general weak acid efflux pump to an acetate-specific efflux pump for efficient cellular defense against acetate stress. CONCLUSIONS Our study has elucidated the role of WatR as a key transcription factor in the cellular defense against weak organic acids, particularly acetate, in Methylomonas sp. DH-1. We identified the genes encoding WatABO efflux pump and small polypeptides (WatS1 to WatS5), as the target genes regulated by WatR for this specific function. These findings offer valuable insights into the mechanisms underlying weak acid tolerance in methanotrophic bacteria, thereby contributing to the development of bioprocesses aimed at converting methane into value-added chemicals.
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Affiliation(s)
- Seungwoo Cha
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Yong-Joon Cho
- Department of Molecular Bioscience, College of Biomedical Science, Kangwon National University, 1 Gangwondaehakgil, Chuncheon, Gangwon-do, 24341, Republic of Korea
| | - Jong Kwan Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Ji-Sook Hahn
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.
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Trampari E, Prischi F, Vargiu AV, Abi-Assaf J, Bavro VN, Webber MA. Functionally distinct mutations within AcrB underpin antibiotic resistance in different lifestyles. NPJ ANTIMICROBIALS AND RESISTANCE 2023; 1:2. [PMID: 38686215 PMCID: PMC11057200 DOI: 10.1038/s44259-023-00001-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 02/27/2023] [Indexed: 05/02/2024]
Abstract
Antibiotic resistance is a pressing healthcare challenge and is mediated by various mechanisms, including the active export of drugs via multidrug efflux systems, which prevent drug accumulation within the cell. Here, we studied how Salmonella evolved resistance to two key antibiotics, cefotaxime and azithromycin, when grown planktonically or as a biofilm. Resistance to both drugs emerged in both conditions and was associated with different substitutions within the efflux-associated transporter, AcrB. Azithromycin exposure selected for an R717L substitution, while cefotaxime for Q176K. Additional mutations in ramR or envZ accumulated concurrently with the R717L or Q176K substitutions respectively, resulting in clinical resistance to the selective antibiotics and cross-resistance to other drugs. Structural, genetic, and phenotypic analysis showed the two AcrB substitutions confer their benefits in profoundly different ways. R717L reduces steric barriers associated with transit through the substrate channel 2 of AcrB. Q176K increases binding energy for cefotaxime, improving recognition in the distal binding pocket, resulting in increased efflux efficiency. Finally, we show the R717 substitution is present in isolates recovered around the world.
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Affiliation(s)
- Eleftheria Trampari
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UQ UK
| | - Filippo Prischi
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ UK
| | - Attilio V. Vargiu
- Department of Physics, University of Cagliari, S. P. 8, km. 0.700, 09042 Monserrato, Italy
| | - Justin Abi-Assaf
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UQ UK
| | - Vassiliy N. Bavro
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ UK
| | - Mark A. Webber
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UQ UK
- Medical School, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7UA UK
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Athar M, Gervasoni S, Catte A, Basciu A, Malloci G, Ruggerone P, Vargiu AV. Tripartite efflux pumps of the RND superfamily: what did we learn from computational studies? MICROBIOLOGY (READING, ENGLAND) 2023; 169. [PMID: 36972322 DOI: 10.1099/mic.0.001307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
Bacterial resistance to antibiotics has been long recognized as a priority to address for human health. Among all micro-organisms, the so-called multi-drug resistant (MDR) bacteria, which are resistant to most, if not all drugs in our current arsenal, are particularly worrisome. The World Health Organization has prioritized the ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species) pathogens, which include four Gram-negative bacterial species. In these bacteria, active extrusion of antimicrobial compounds out of the cell by means of 'molecular guns' known as efflux pumps is a main determinant of MDR phenotypes. The resistance-nodulation-cell division (RND) superfamily of efflux pumps connecting the inner and outer membrane in Gram-negative bacteria is crucial to the onset of MDR and virulence, as well as biofilm formation. Thus, understanding the molecular basis of the interaction of antibiotics and inhibitors with these pumps is key to the design of more effective therapeutics. With the aim to contribute to this challenge, and complement and inspire experimental research, in silico studies on RND efflux pumps have flourished in recent decades. Here, we review a selection of such investigations addressing the main determinants behind the polyspecificity of these pumps, the mechanisms of substrate recognition, transport and inhibition, as well as the relevance of their assembly for proper functioning, and the role of protein-lipid interactions. The journey will end with a perspective on the role of computer simulations in addressing the challenges posed by these beautifully complex machineries and in supporting the fight against the spread of MDR bacteria.
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Affiliation(s)
- Mohd Athar
- Physics Department, University of Cagliari, Cittadella Universitaria, SP 8 km 0.700, 09042, Monserrato (CA), Italy
| | - Silvia Gervasoni
- Physics Department, University of Cagliari, Cittadella Universitaria, SP 8 km 0.700, 09042, Monserrato (CA), Italy
| | - Andrea Catte
- Physics Department, University of Cagliari, Cittadella Universitaria, SP 8 km 0.700, 09042, Monserrato (CA), Italy
| | - Andrea Basciu
- Physics Department, University of Cagliari, Cittadella Universitaria, SP 8 km 0.700, 09042, Monserrato (CA), Italy
| | - Giuliano Malloci
- Physics Department, University of Cagliari, Cittadella Universitaria, SP 8 km 0.700, 09042, Monserrato (CA), Italy
| | - Paolo Ruggerone
- Physics Department, University of Cagliari, Cittadella Universitaria, SP 8 km 0.700, 09042, Monserrato (CA), Italy
| | - Attilio Vittorio Vargiu
- Physics Department, University of Cagliari, Cittadella Universitaria, SP 8 km 0.700, 09042, Monserrato (CA), Italy
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RND Pump-Mediated Efflux of Amotosalen, a Compound Used in Pathogen Inactivation Technology to Enhance Safety of Blood Transfusion Products, May Compromise Its Gram-Negative Anti-Bacterial Activity. mSphere 2023; 8:e0067322. [PMID: 36853056 PMCID: PMC10117049 DOI: 10.1128/msphere.00673-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
Pathogen inactivation is a strategy to improve the safety of transfusion products. The only pathogen reduction technology for blood products currently approved in the US utilizes a psoralen compound, called amotosalen, in combination with UVA light to inactivate bacteria, viruses, and protozoa. Psoralens have structural similarity to bacterial multidrug efflux pump substrates. As these efflux pumps are often overexpressed in multidrug-resistant pathogens, we tested whether contemporary drug-resistant pathogens might show resistance to amotosalen and other psoralens based on multidrug efflux mechanisms through genetic, biophysical, and molecular modeling analysis. The main efflux systems in Enterobacterales, Acinetobacter baumannii, and Pseudomonas aeruginosa are tripartite resistance-nodulation-cell division (RND) systems, which span the inner and outer membranes of Gram-negative pathogens, and expel antibiotics from the bacterial cytoplasm into the extracellular space. We provide evidence that amotosalen is an efflux substrate for the E. coli AcrAB, Acinetobacter baumannii AdeABC, and P. aeruginosa MexXY RND efflux pumps. Furthermore, we show that the MICs for contemporary Gram-negative bacterial isolates for these species and others in vitro approached and exceeded the concentration of amotosalen used in the approved platelet and plasma inactivation procedures. These findings suggest that otherwise safe and effective inactivation methods should be further studied to identify possible gaps in their ability to inactivate contemporary, multidrug-resistant bacterial pathogens. IMPORTANCE Pathogen inactivation is a strategy to enhance the safety of transfused blood products. We identify the compound, amotosalen, widely used for pathogen inactivation, as a bacterial multidrug efflux substrate. Specifically, experiments suggest that amotosalen is pumped out of bacteria by major efflux pumps in E. coli, Acinetobacter baumannii, and Pseudomonas aeruginosa. Such efflux pumps are often overexpressed in multidrug-resistant pathogens. Importantly, the MICs for contemporary multidrug-resistant Enterobacterales, Acinetobacter baumannii, Pseudomonas aeruginosa, Burkholderia spp., and Stenotrophomonas maltophilia isolates approached or exceeded the amotosalen concentration used in approved platelet and plasma inactivation procedures, potentially as a result of efflux pump activity. Although there are important differences in methodology between our experiments and blood product pathogen inactivation, these findings suggest that otherwise safe and effective inactivation methods should be further studied to identify possible gaps in their ability to inactivate contemporary, multidrug-resistant bacterial pathogens.
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Update on the Discovery of Efflux Pump Inhibitors against Critical Priority Gram-Negative Bacteria. Antibiotics (Basel) 2023; 12:antibiotics12010180. [PMID: 36671381 PMCID: PMC9854755 DOI: 10.3390/antibiotics12010180] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
Antimicrobial resistance (AMR) has become a major problem in public health leading to an estimated 4.95 million deaths in 2019. The selective pressure caused by the massive and repeated use of antibiotics has led to bacterial strains that are partially or even entirely resistant to known antibiotics. AMR is caused by several mechanisms, among which the (over)expression of multidrug efflux pumps plays a central role. Multidrug efflux pumps are transmembrane transporters, naturally expressed by Gram-negative bacteria, able to extrude and confer resistance to several classes of antibiotics. Targeting them would be an effective way to revive various options for treatment. Many efflux pump inhibitors (EPIs) have been described in the literature; however, none of them have entered clinical trials to date. This review presents eight families of EPIs active against Escherichia coli or Pseudomonas aeruginosa. Structure-activity relationships, chemical synthesis, in vitro and in vivo activities, and pharmacological properties are reported. Their binding sites and their mechanisms of action are also analyzed comparatively.
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14
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Spatial Characteristics of the Efflux Pump MexB Determine Inhibitor Binding. Antimicrob Agents Chemother 2022; 66:e0067222. [DOI: 10.1128/aac.00672-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The multidrug efflux transporters MexB and MexY in
Pseudomonas aeruginosa
and AcrB in
Escherichia coli
contribute to these organisms’ multidrug resistance. Efflux pump inhibitor (EPI) ABI-PP inhibits MexB and AcrB, but not MexY.
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15
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A genetic platform to investigate the functions of bacterial drug efflux pumps. Nat Chem Biol 2022; 18:1399-1409. [PMID: 36065018 DOI: 10.1038/s41589-022-01119-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 07/21/2022] [Indexed: 11/08/2022]
Abstract
Efflux pumps are a serious challenge for the development of antibacterial agents. Overcoming efflux requires an in-depth understanding of efflux pump functions, specificities and the development of inhibitors. However, the complexities of efflux networks have limited such studies. To address these challenges, we generated Efflux KnockOut-35 (EKO-35), a highly susceptible Escherichia coli strain lacking 35 efflux pumps. We demonstrate the use of this strain by constructing an efflux platform comprising EKO-35 strains individually producing efflux pumps forming tripartite complexes with TolC. This platform was profiled against a curated diverse compound collection, which enabled us to define physicochemical properties that contribute to transport. We also show the E. coli drug efflux network is conditionally essential for growth, and that the platform can be used to investigate efflux pump inhibitor specificities and efflux pump interplay. We believe EKO-35 and the efflux platform will have widespread application for the study of drug efflux.
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Gervasoni S, Malloci G, Bosin A, Vargiu AV, Zgurskaya HI, Ruggerone P. Recognition of quinolone antibiotics by the multidrug efflux transporter MexB of Pseudomonas aeruginosa. Phys Chem Chem Phys 2022; 24:16566-16575. [PMID: 35766032 PMCID: PMC9278589 DOI: 10.1039/d2cp00951j] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The drug/proton antiporter MexB is the engine of the major efflux pump MexAB-OprM in Pseudomonas aeruginosa. This protein is known to transport a large variety of compounds, including antibiotics, thus conferring a multi-drug resistance phenotype. Due to the difficulty of producing co-crystals, only two X-ray structures of MexB in a complex with ligands are available to date, and mechanistic aspects are largely hypothesized based on the body of data collected for the homologous protein AcrB of Escherichia coli. In particular, a recent study (Ornik-Cha, Wilhelm, Kobylka et al., Nat. Commun., 2021, 12, 6919) reported a co-crystal structure of AcrB in a complex with levofloxacin, an antibiotic belonging to the important class of (fluoro)-quinolones. In this work, we performed a systematic ensemble docking campaign coupled to the cluster analysis and molecular-mechanics optimization of docking poses to study the interaction between 36 quinolone antibiotics and MexB. We additionally investigated surface complementarity between each molecule and the transporter and thoroughly assessed the computational protocol adopted against the known experimental data. Our study reveals different binding preferences of the investigated compounds towards the sub-sites of the large deep binding pocket of MexB, supporting the hypothesis that MexB substrates oscillate between different binding modes with similar affinity. Interestingly, small changes in the molecular structure translate into significant differences in MexB–quinolone interactions. All the predicted binding modes are available for download and visualization at the following link: https://www.dsf.unica.it/dock/mexb/quinolones. Putative binding modes (BMs) of quinolones to the bacterial efflux transporter MexB were identified. Multiple interaction patterns are possible, supporting the hypothesis that substrates oscillate between different BMs with similar affinity.![]()
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Affiliation(s)
- Silvia Gervasoni
- Department of Physics, University of Cagliari, Citt. Universitaria, I-09042 Monserrato (Cagliari), Italy.
| | - Giuliano Malloci
- Department of Physics, University of Cagliari, Citt. Universitaria, I-09042 Monserrato (Cagliari), Italy.
| | - Andrea Bosin
- Department of Physics, University of Cagliari, Citt. Universitaria, I-09042 Monserrato (Cagliari), Italy.
| | - Attilio V Vargiu
- Department of Physics, University of Cagliari, Citt. Universitaria, I-09042 Monserrato (Cagliari), Italy.
| | - Helen I Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73072, USA
| | - Paolo Ruggerone
- Department of Physics, University of Cagliari, Citt. Universitaria, I-09042 Monserrato (Cagliari), Italy.
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17
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Akermi S, Smaoui S, Elhadef K, Fourati M, Louhichi N, Chaari M, Chakchouk Mtibaa A, Baanannou A, Masmoudi S, Mellouli L. Cupressus sempervirens Essential Oil: Exploring the Antibacterial Multitarget Mechanisms, Chemcomputational Toxicity Prediction, and Safety Assessment in Zebrafish Embryos. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27092630. [PMID: 35565980 PMCID: PMC9103706 DOI: 10.3390/molecules27092630] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/11/2022] [Accepted: 04/18/2022] [Indexed: 12/11/2022]
Abstract
Nowadays, increasing interest has recently been given to the exploration of new food preservatives to avoid foodborne outbreaks or food spoilage. Likewise, new compounds that substitute the commonly used synthetic food preservatives are required to restrain the rising problem of microbial resistance. Accordingly, the present study was conducted to examine the chemical composition and the mechanism(s) of action of the Cupressus sempervirens essential oil (CSEO) against Salmonella enterica Typhimuriumand Staphyloccocus aureus. The gas chromatography analysis revealed α-pinene (38.47%) and δ-3-carene (25.14%) are the major components of the CSEO. By using computational methods, such as quantitative structure–activity relationship (QSAR), we revealed that many CSEO components had no toxic effects. Moreover, findings indicated that α-pinene, δ-3-carene and borneol, a minor compound of CSEO, could inhibit the AcrB-TolC and MepR efflux pump activity of S. enterica Typhimurium and S. aureus, respectively. In addition, our molecular docking predictions indicated the high affinity of these three compounds with active sites of bacterial DNA and RNA polymerases, pointing to plausible impairments of the pathogenic bacteria cell replication processes. As well, the safety profile was developed through the zebrafish model. The in vivo toxicological evaluation of (CSEO) exhibited a concentration-dependent manner, with a lethal concentration (LC50) equal to 6.6 µg/mL.
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Affiliation(s)
- Sarra Akermi
- Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (S.A.); (K.E.); (M.F.); (M.C.); (A.C.M.); (L.M.)
| | - Slim Smaoui
- Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (S.A.); (K.E.); (M.F.); (M.C.); (A.C.M.); (L.M.)
- Correspondence: ; Tel.: +216-53759478
| | - Khaoula Elhadef
- Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (S.A.); (K.E.); (M.F.); (M.C.); (A.C.M.); (L.M.)
| | - Mariam Fourati
- Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (S.A.); (K.E.); (M.F.); (M.C.); (A.C.M.); (L.M.)
| | - Nacim Louhichi
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (N.L.); (A.B.); (S.M.)
| | - Moufida Chaari
- Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (S.A.); (K.E.); (M.F.); (M.C.); (A.C.M.); (L.M.)
| | - Ahlem Chakchouk Mtibaa
- Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (S.A.); (K.E.); (M.F.); (M.C.); (A.C.M.); (L.M.)
| | - Aissette Baanannou
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (N.L.); (A.B.); (S.M.)
| | - Saber Masmoudi
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (N.L.); (A.B.); (S.M.)
| | - Lotfi Mellouli
- Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia; (S.A.); (K.E.); (M.F.); (M.C.); (A.C.M.); (L.M.)
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18
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Dey N, Kamatchi C, Vickram AS, Anbarasu K, Thanigaivel S, Palanivelu J, Pugazhendhi A, Ponnusamy VK. Role of nanomaterials in deactivating multiple drug resistance efflux pumps - A review. ENVIRONMENTAL RESEARCH 2022; 204:111968. [PMID: 34453898 DOI: 10.1016/j.envres.2021.111968] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 08/05/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
The changes in lifestyle and living conditions have affected not only humans but also microorganisms. As man invents new drugs and therapies, pathogens alter themselves to survive and thrive. Multiple drug resistance (MDR) is the talk of the town for decades now. Many generations of medications have been termed useless as MDR rises among the infectious population. The surge in nanotechnology has brought a new hope in reducing this aspect of resistance in pathogens. It has been observed in several laboratory-based studies that the use of nanoparticles had a synergistic effect on the antibiotic being administered to the pathogen; several resistant strains scummed to the stress created by the nanoparticles and became susceptible to the drug. The major cause of resistance to date is the efflux system, which makes the latest generation of antibiotics ineffective without reaching the target site. If species-specific nanomaterials are used to control the activity of efflux pumps, it could revolutionize the field of medicine and make the previous generation resistant medications active once again. Therefore, the current study was devised to assess and review nanoparticles' role on efflux systems and discuss how specialized particles can be designed towards an infectious host's particular drug ejection systems.
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Affiliation(s)
- Nibedita Dey
- Department of Biotechnology, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Chennai, India
| | - C Kamatchi
- Department of Biotechnology, The Oxford College of Science, Bengaluru, India
| | - A S Vickram
- Department of Biotechnology, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Chennai, India
| | - K Anbarasu
- Department of Bioinformatics, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Chennai, India
| | - S Thanigaivel
- Department of Biomedical Engineering, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Chennai, India
| | - Jeyanthi Palanivelu
- Department of Biotechnology, Vel Tech Rangarajan Dr. Sagunthala R&D Institute of Science and Technology, Chennai, India
| | | | - Vinoth Kumar Ponnusamy
- Department of Medicinal and Applied Chemistry & Research Center for Environmental Medicine, Kaohsiung Medical University (KMU), Kaohsiung City, 807, Taiwan; Department of Medical Research, Kaohsiung Medical University Hospital (KMUH), Kaohsiung City, 807, Taiwan; Program of Aquatic Science and Technology, College of Hydrosphere Science, National Kaohsiung University of Science and Technology (NKUST), Kaohsiung City, Taiwan.
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19
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Ikehata Y, Doukyu N. Improving the organic solvent tolerance of Escherichia coli with vanillin, and the involvement of an AcrAB-TolC efflux pump in vanillin tolerance. J Biosci Bioeng 2022; 133:347-352. [DOI: 10.1016/j.jbiosc.2021.12.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 12/07/2021] [Accepted: 12/28/2021] [Indexed: 10/19/2022]
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20
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Li Q, Zhang J, Yang J, Jiang Y, Yang S. Recent progress on n-butanol production by lactic acid bacteria. World J Microbiol Biotechnol 2021; 37:205. [PMID: 34698975 DOI: 10.1007/s11274-021-03173-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 10/13/2021] [Indexed: 11/26/2022]
Abstract
n-Butanol is an essential chemical intermediate produced through microbial fermentation. However, its toxicity to microbial cells has limited its production to a great extent. The anaerobe lactic acid bacteria (LAB) are the most resistant to n-butanol, so it should be the first choice for improving n-butanol production. The present article aims to review the following aspects of n-butanol production by LAB: (1) the tolerance of LAB to n-butanol, including its tolerance level and potential tolerance mechanisms; (2) genome editing tools in the n-butanol-resistant LAB; (3) methods of LAB modification for n-butanol production and the production levels after modification. This review will provide a theoretical basis for further research on n-butanol production by LAB.
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Affiliation(s)
- Qi Li
- College of Life Sciences, Sichuan Normal University, Chengdu, 610101, China
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032, China
| | - Jieze Zhang
- Department of Chemistry, University of Southern California, Los Angeles, CA, 90089, USA
| | - Junjie Yang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032, China
| | - Yu Jiang
- Huzhou Center of Industrial Biotechnology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Huzhou, 313000, China
- Shanghai Taoyusheng Biotechnology Company Ltd, Shanghai, 200032, China
| | - Sheng Yang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032, China.
- Huzhou Center of Industrial Biotechnology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Huzhou, 313000, China.
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21
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Bharatham N, Bhowmik P, Aoki M, Okada U, Sharma S, Yamashita E, Shanbhag AP, Rajagopal S, Thomas T, Sarma M, Narjari R, Nagaraj S, Ramachandran V, Katagihallimath N, Datta S, Murakami S. Structure and function relationship of OqxB efflux pump from Klebsiella pneumoniae. Nat Commun 2021; 12:5400. [PMID: 34518546 PMCID: PMC8437966 DOI: 10.1038/s41467-021-25679-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 08/20/2021] [Indexed: 02/08/2023] Open
Abstract
OqxB is an RND (Resistance-Nodulation-Division) efflux pump that has emerged as a factor contributing to the antibiotic resistance in Klebsiella pneumoniae. OqxB underwent horizontal gene transfer and is now seen in other Gram-negative bacterial pathogens including Escherichia coli, Enterobacter cloacae and Salmonella spp., further disseminating multi-drug resistance. In this study, we describe crystal structure of OqxB with n-dodecyl-β-D-maltoside (DDM) molecules bound in its substrate-binding pocket, at 1.85 Å resolution. We utilize this structure in computational studies to predict the key amino acids contributing to the efflux of fluoroquinolones by OqxB, distinct from analogous residues in related transporters AcrB and MexB. Finally, our complementation assays with mutated OqxB and minimum inhibitory concentration (MIC) experiments with clinical isolates of E. coli provide further evidence that the predicted structural features are indeed involved in ciprofloxacin efflux.
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Affiliation(s)
- Nagakumar Bharatham
- grid.413008.e0000 0004 1765 8271Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, GKVK, Bellary Rd, Bengaluru, Karnataka India ,grid.502290.cThe University of Trans-Disciplinary Health Sciences and Technology (TDU), Bengaluru, Karnataka India
| | - Purnendu Bhowmik
- grid.413008.e0000 0004 1765 8271Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, GKVK, Bellary Rd, Bengaluru, Karnataka India ,grid.502290.cThe University of Trans-Disciplinary Health Sciences and Technology (TDU), Bengaluru, Karnataka India
| | - Maho Aoki
- grid.32197.3e0000 0001 2179 2105Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Ui Okada
- grid.32197.3e0000 0001 2179 2105Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Sreevalli Sharma
- grid.413008.e0000 0004 1765 8271Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, GKVK, Bellary Rd, Bengaluru, Karnataka India ,grid.502290.cThe University of Trans-Disciplinary Health Sciences and Technology (TDU), Bengaluru, Karnataka India
| | - Eiki Yamashita
- grid.136593.b0000 0004 0373 3971Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Anirudh P. Shanbhag
- grid.413008.e0000 0004 1765 8271Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, GKVK, Bellary Rd, Bengaluru, Karnataka India
| | - Sreenath Rajagopal
- grid.413008.e0000 0004 1765 8271Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, GKVK, Bellary Rd, Bengaluru, Karnataka India
| | - Teby Thomas
- grid.418280.70000 0004 1794 3160St. John’s Research Institute, Bengaluru, Karnataka India
| | - Maitrayee Sarma
- grid.413008.e0000 0004 1765 8271Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, GKVK, Bellary Rd, Bengaluru, Karnataka India
| | - Riya Narjari
- grid.413008.e0000 0004 1765 8271Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, GKVK, Bellary Rd, Bengaluru, Karnataka India
| | | | - Vasanthi Ramachandran
- grid.413008.e0000 0004 1765 8271Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, GKVK, Bellary Rd, Bengaluru, Karnataka India ,grid.502290.cThe University of Trans-Disciplinary Health Sciences and Technology (TDU), Bengaluru, Karnataka India
| | - Nainesh Katagihallimath
- grid.413008.e0000 0004 1765 8271Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, GKVK, Bellary Rd, Bengaluru, Karnataka India ,grid.502290.cThe University of Trans-Disciplinary Health Sciences and Technology (TDU), Bengaluru, Karnataka India
| | - Santanu Datta
- grid.413008.e0000 0004 1765 8271Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, GKVK, Bellary Rd, Bengaluru, Karnataka India
| | - Satoshi Murakami
- grid.32197.3e0000 0001 2179 2105Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
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D’Cunha N, Moniruzzaman M, Haynes K, Malloci G, Cooper CJ, Margiotta E, Vargiu AV, Uddin MR, Leus IV, Cao F, Parks JM, Rybenkov VV, Ruggerone P, Zgurskaya HI, Walker JK. Mechanistic Duality of Bacterial Efflux Substrates and Inhibitors: Example of Simple Substituted Cinnamoyl and Naphthyl Amides. ACS Infect Dis 2021; 7:2650-2665. [PMID: 34379382 DOI: 10.1021/acsinfecdis.1c00100] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Antibiotic resistance poses an immediate and growing threat to human health. Multidrug efflux pumps are promising targets for overcoming antibiotic resistance with small-molecule therapeutics. Previously, we identified a diaminoquinoline acrylamide, NSC-33353, as a potent inhibitor of the AcrAB-TolC efflux pump in Escherichia coli. This inhibitor potentiates the antibacterial activities of novobiocin and erythromycin upon binding to the membrane fusion protein AcrA. It is also a substrate for efflux and lacks appreciable intrinsic antibacterial activity of its own in wild-type cells. Here, we have modified the substituents of the cinnamoyl group of NSC-33353, giving rise to analogs that retain the ability to inhibit efflux, lost the features of the efflux substrates, and gained antibacterial activity in wild-type cells. The replacement of the cinnamoyl group with naphthyl isosteres generated compounds that lack antibacterial activity but are both excellent efflux pump inhibitors and substrates. Surprisingly, these inhibitors potentiate the antibacterial activity of novobiocin but not erythromycin. Surface plasmon resonance experiments and molecular docking suggest that the replacement of the cinnamoyl group with naphthyl shifts the affinity of the compounds away from AcrA to the AcrB transporter, making them better efflux substrates and changing their mechanism of inhibition. These results provide new insights into the duality of efflux substrate/inhibitor features in chemical scaffolds that will facilitate the development of new efflux pump inhibitors.
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Affiliation(s)
- Napoleon D’Cunha
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, Missouri 63110, United States
| | - Mohammad Moniruzzaman
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73072, United States
| | - Keith Haynes
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, Missouri 63110, United States
| | - Giuliano Malloci
- Department of Physics, University of Cagliari, Monserrato, Cagliari 09042, Italy
| | - Connor J. Cooper
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, Tennessee 37996, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Enrico Margiotta
- Department of Physics, University of Cagliari, Monserrato, Cagliari 09042, Italy
| | - Attilio V. Vargiu
- Department of Physics, University of Cagliari, Monserrato, Cagliari 09042, Italy
| | - Muhammad R. Uddin
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73072, United States
| | - Inga V. Leus
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73072, United States
| | - Feng Cao
- John Cochran Division, Department of Veteran Affairs Medical Center, St. Louis, Missouri 63106, United States
| | - Jerry M. Parks
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Valentin V. Rybenkov
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73072, United States
| | - Paolo Ruggerone
- Department of Physics, University of Cagliari, Monserrato, Cagliari 09042, Italy
| | - Helen I. Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73072, United States
| | - John K. Walker
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, Missouri 63110, United States
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Structural Insights into Transporter-Mediated Drug Resistance in Infectious Diseases. J Mol Biol 2021; 433:167005. [PMID: 33891902 DOI: 10.1016/j.jmb.2021.167005] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/12/2021] [Accepted: 04/12/2021] [Indexed: 02/07/2023]
Abstract
Infectious diseases present a major threat to public health globally. Pathogens can acquire resistance to anti-infectious agents via several means including transporter-mediated efflux. Typically, multidrug transporters feature spacious, dynamic, and chemically malleable binding sites to aid in the recognition and transport of chemically diverse substrates across cell membranes. Here, we discuss recent structural investigations of multidrug transporters involved in resistance to infectious diseases that belong to the ATP-binding cassette (ABC) superfamily, the major facilitator superfamily (MFS), the drug/metabolite transporter (DMT) superfamily, the multidrug and toxic compound extrusion (MATE) family, the small multidrug resistance (SMR) family, and the resistance-nodulation-division (RND) superfamily. These structural insights provide invaluable information for understanding and combatting multidrug resistance.
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Ahmed MS, Lauersen KJ, Ikram S, Li C. Efflux Transporters' Engineering and Their Application in Microbial Production of Heterologous Metabolites. ACS Synth Biol 2021; 10:646-669. [PMID: 33751883 DOI: 10.1021/acssynbio.0c00507] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Metabolic engineering of microbial hosts for the production of heterologous metabolites and biochemicals is an enabling technology to generate meaningful quantities of desired products that may be otherwise difficult to produce by traditional means. Heterologous metabolite production can be restricted by the accumulation of toxic products within the cell. Efflux transport proteins (transporters) provide a potential solution to facilitate the export of these products, mitigate toxic effects, and enhance production. Recent investigations using knockout lines, heterologous expression, and expression profiling of transporters have revealed candidates that can enhance the export of heterologous metabolites from microbial cell systems. Transporter engineering efforts have revealed that some exhibit flexible substrate specificity and may have broader application potentials. In this Review, the major superfamilies of efflux transporters, their mechanistic modes of action, selection of appropriate efflux transporters for desired compounds, and potential transporter engineering strategies are described for potential applications in enhancing engineered microbial metabolite production. Future studies in substrate recognition, heterologous expression, and combinatorial engineering of efflux transporters will assist efforts to enhance heterologous metabolite production in microbial hosts.
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Affiliation(s)
- Muhammad Saad Ahmed
- Institute for Synthetic Biosystem/Department of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology (BIT), Beijing 100081, P. R. China
- Department of Biological Sciences, National University of Medical Sciences (NUMS), Abid Majeed Road, The Mall, Rawalpindi 46000, Pakistan
| | - Kyle J. Lauersen
- Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Kingdom of Saudi Arabia
| | - Sana Ikram
- Beijing Higher Institution Engineering Research Center for Food Additives and Ingredients, Beijing Technology & Business University (BTBU), Beijing 100048, P. R. China
| | - Chun Li
- Institute for Synthetic Biosystem/Department of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology (BIT), Beijing 100081, P. R. China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Key Laboratory of Systems Bioengineering, Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, P. R. China
- Key Laboratory for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, P. R. China
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Physicochemical and Structural Parameters Contributing to the Antibacterial Activity and Efflux Susceptibility of Small-Molecule Inhibitors of Escherichia coli. Antimicrob Agents Chemother 2021; 65:AAC.01925-20. [PMID: 33468483 DOI: 10.1128/aac.01925-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 01/06/2021] [Indexed: 11/20/2022] Open
Abstract
Discovering new Gram-negative antibiotics has been a challenge for decades. This has been largely attributed to a limited understanding of the molecular descriptors governing Gram-negative permeation and efflux evasion. Herein, we address the contribution of efflux using a novel approach that applies multivariate analysis, machine learning, and structure-based clustering to some 4,500 molecules (actives) from a small-molecule screen in efflux-compromised Escherichia coli We employed principal-component analysis and trained two decision tree-based machine learning models to investigate descriptors contributing to the antibacterial activity and efflux susceptibility of these actives. This approach revealed that the Gram-negative activity of hydrophobic and planar small molecules with low molecular stability is limited to efflux-compromised E. coli Furthermore, molecules with reduced branching and compactness showed increased susceptibility to efflux. Given these distinct properties that govern efflux, we developed the first efflux susceptibility machine learning model, called Susceptibility to Efflux Random Forest (SERF), as a tool to analyze the molecular descriptors of small molecules and predict those that could be susceptible to efflux pumps in silico Here, SERF demonstrated high accuracy in identifying such molecules. Furthermore, we clustered all 4,500 actives based on their core structures and identified distinct clusters highlighting side-chain moieties that cause marked changes in efflux susceptibility. In all, our work reveals a role for physicochemical and structural parameters in governing efflux, presents a machine learning tool for rapid in silico analysis of efflux susceptibility, and provides a proof of principle for the potential of exploiting side-chain modification to design novel antimicrobials evading efflux pumps.
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Pan X, Cen Y, Kuang M, Li B, Qin R, Zhou H. Artesunate interrupts the self-transcriptional activation of MarA to inhibit RND family pumps of Escherichia coli. Int J Med Microbiol 2020; 310:151465. [PMID: 33238228 DOI: 10.1016/j.ijmm.2020.151465] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 10/14/2020] [Accepted: 11/05/2020] [Indexed: 11/25/2022] Open
Abstract
Resistance-Nodulation-Division (RND) family pumps are responsible for producing multidrug resistance in Escherichia coli; however, there has been little study of targeted inhibitors of RNDs. In the present study, we investigated the inhibition of RND pumps by artesunate (AS) in E. coli, and further investigated the mechanism with respect to MarA, a regulator of RNDs. Although AS had no direct antibacterial effect, it showed a synergistic effect in combination with β-lactams against E. coli ATCC35218 in vitro and in vivo, suggesting it possesses antibacterial enhancement activity. Notably, AS, alone or in combination with β-lactams, downregulated the mRNA expression levels of marA, soxS, and rob, known as the marA-soxS-rob regulon, which then decreased the expression levels of RNDs, thereby increased ampicillin accumulation within ATCC35218. Using gene-deletion strains, we found that the antibacterial sensitization effect of AS persisted in wildtype bacteria, but was completely lost in the strain lacking marA, and decreased in the strain lacking soxS or rob, suggesting marA plays a crucial role in the sensitization of AS. Critically, we showed that AS inhibited the binding of MarA to the promoter of marA itself, not acrB, resulting in decreased mRNA expression of both acrB and marA. Mechanistically, we found AS directly bound to the central cavity of MarA through the R59 and K62 residues, and thus altered the charge distribution of MarA to interrupt the recognition between MarA and its promoter. We concluded that AS interrupts the self-transcriptional activation of MarA, thereby inhibits MarA-dependent mRNA expression of marA, acrAB, and tolC, and also certain other RNDs and regulatory genes related to MarA. Therefore, AS is a novel inhibitor of RND pumps that acts on the regulator MarA.
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Affiliation(s)
- Xichun Pan
- Department of Pharmacology, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing 400038, PR China
| | - Yanyan Cen
- Department of Pharmacology, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing 400038, PR China
| | - Mei Kuang
- Department of Pharmacology, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing 400038, PR China
| | - Bin Li
- Department of Pharmacology, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing 400038, PR China
| | - Rongxin Qin
- Department of Pharmacology, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing 400038, PR China
| | - Hong Zhou
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, 563003, PR China.
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Serçinoğlu O, Senturk D, Altinisik Kaya FE, Avci FG, Frlan R, Tomašič T, Ozbek P, Orelle C, Jault JM, Sariyar Akbulut B. Identification of novel inhibitors of the ABC transporter BmrA. Bioorg Chem 2020; 105:104452. [PMID: 33212311 DOI: 10.1016/j.bioorg.2020.104452] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 10/23/2020] [Accepted: 11/01/2020] [Indexed: 01/02/2023]
Abstract
The resistance of microbes to commonly used antibiotics has become a worldwide health problem. A major underlying mechanism of microbial antibiotic resistance is the export of drugs from bacterial cells. Drug efflux is mediated through the action of multidrug resistance efflux pumps located in the bacterial cell membranes. The critical role of bacterial efflux pumps in antibiotic resistance has directed research efforts to the identification of novel efflux pump inhibitors that can be used alongside antibiotics in clinical settings. Here, we aimed to find potential inhibitors of the archetypical ATP-binding cassette (ABC) efflux pump BmrA of Bacillus subtilis via virtual screening of the Mu.Ta.Lig. Chemotheca small molecule library. Molecular docking calculations targeting the nucleotide-binding domain of BmrA were performed using AutoDock Vina. Following a further drug-likeness filtering step based on Lipinski's Rule of Five, top 25 scorers were identified. These ligands were then clustered into separate groups based on their contact patterns with the BmrA nucleotide-binding domain. Six ligands with distinct contact patterns were used for further in vitro inhibition assays based on intracellular ethidium bromide accumulation. Using this methodology, we identified two novel inhibitors of BmrA from the Chemotheca small molecule library.
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Affiliation(s)
- Onur Serçinoğlu
- Department of Bioengineering, Recep Tayyip Erdogan University, Fener 53100, Rize, Turkey
| | - Duygu Senturk
- Department of Bioengineering, Marmara University, Kadikoy 34722, Istanbul, Turkey
| | | | - Fatma Gizem Avci
- Department of Bioengineering, Uskudar University, Uskudar 34662, Istanbul, Turkey
| | - Rok Frlan
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, 1000 Ljubljana, Slovenia
| | - Tihomir Tomašič
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, 1000 Ljubljana, Slovenia
| | - Pemra Ozbek
- Department of Bioengineering, Marmara University, Kadikoy 34722, Istanbul, Turkey
| | - Cédric Orelle
- University of Lyon, CNRS, UMR5086 "Molecular Microbiology and Structural Biochemistry", 7 passage du Vercors, 69367 Lyon Cedex 7, France
| | - Jean-Michel Jault
- University of Lyon, CNRS, UMR5086 "Molecular Microbiology and Structural Biochemistry", 7 passage du Vercors, 69367 Lyon Cedex 7, France
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Lu WJ, Lin HJ, Hsu PH, Lin HTV. Determination of Drug Efflux Pump Efficiency in Drug-Resistant Bacteria Using MALDI-TOF MS. Antibiotics (Basel) 2020; 9:antibiotics9100639. [PMID: 32987695 PMCID: PMC7598683 DOI: 10.3390/antibiotics9100639] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 09/18/2020] [Accepted: 09/22/2020] [Indexed: 12/26/2022] Open
Abstract
Multidrug efflux pumps play an essential role in antibiotic resistance. The conventional methods, including minimum inhibitory concentration and fluorescent assays, to monitor transporter efflux activity might have some drawbacks, such as indirect evidence or interference from color molecules. In this study, MALDI-TOF MS use was explored for monitoring drug efflux by a multidrug transporter, and the results were compared for validation with the data from conventional methods. Minimum inhibitory concentration was used first to evaluate the activity of Escherichia coli drug transporter AcrB, and this analysis showed that the E. coli overexpressing AcrB exhibited elevated resistance to various antibiotics and dyes. Fluorescence-based studies indicated that AcrB in E. coli could decrease the accumulation of intracellular dyes and display various efflux rate constants for different dyes, suggesting AcrB’s efflux activity. The MALDI-TOF MS analysis parameters were optimized to maintain a detection accuracy for AcrB’s substrates; furthermore, the MS data showed that E. coli overexpressing AcrB led to increased ions abundancy of various dyes and drugs in the extracellular space at different rates over time, illustrating continuous substrate efflux by AcrB. This study concluded that MALDI-TOF MS is a reliable method that can rapidly determine the drug pump efflux activity for various substrates.
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Affiliation(s)
- Wen-Jung Lu
- Department of Food Science, National Taiwan Ocean University, No. 2, Pei-Ning Road, Keelung 202, Taiwan; (W.-J.L.); (H.-J.L.)
| | - Hsuan-Ju Lin
- Department of Food Science, National Taiwan Ocean University, No. 2, Pei-Ning Road, Keelung 202, Taiwan; (W.-J.L.); (H.-J.L.)
| | - Pang-Hung Hsu
- Department of Bioscience and Biotechnology, National Taiwan Ocean University, No. 2, Pei-Ning Road, Keelung 202, Taiwan
- Center of Excellence for the Oceans, National Taiwan Ocean University, No. 2, Pei-Ning Road, Keelung 202, Taiwan
- Institute of Biochemistry and Molecular Biology, National Yang Ming University, No. 155, Sec. 2, Linong Street, Taipei 112, Taiwan
- Correspondence: (P.-H.H.); (H.-T.V.L.); Tel.: +886-2-2462-2192 (ext. 5567) (P.-H.H.); +886-2-2462-2192 (ext. 5121) (H.-T.V.L.); Fax: +886-2-2463-4203 (H.-T.V.L.)
| | - Hong-Ting Victor Lin
- Department of Food Science, National Taiwan Ocean University, No. 2, Pei-Ning Road, Keelung 202, Taiwan; (W.-J.L.); (H.-J.L.)
- Center of Excellence for the Oceans, National Taiwan Ocean University, No. 2, Pei-Ning Road, Keelung 202, Taiwan
- Correspondence: (P.-H.H.); (H.-T.V.L.); Tel.: +886-2-2462-2192 (ext. 5567) (P.-H.H.); +886-2-2462-2192 (ext. 5121) (H.-T.V.L.); Fax: +886-2-2463-4203 (H.-T.V.L.)
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Baral B, Mozafari MR. Strategic Moves of "Superbugs" Against Available Chemical Scaffolds: Signaling, Regulation, and Challenges. ACS Pharmacol Transl Sci 2020; 3:373-400. [PMID: 32566906 PMCID: PMC7296549 DOI: 10.1021/acsptsci.0c00005] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Indexed: 12/12/2022]
Abstract
Superbugs' resistivity against available natural products has become an alarming global threat, causing a rapid deterioration in public health and claiming tens of thousands of lives yearly. Although the rapid discovery of small molecules from plant and microbial origin with enhanced bioactivity has provided us with some hope, a rapid hike in the resistivity of superbugs has proven to be the biggest therapeutic hurdle of all times. Moreover, several distinct mechanisms endowed by these notorious superbugs make them immune to these antibiotics subsequently causing our antibiotic wardrobe to be obsolete. In this unfortunate situation, though the time frame for discovering novel "hit molecules" down the line remains largely unknown, our small hope and untiring efforts injected in hunting novel chemical scaffolds with unique molecular targets using high-throughput technologies may safeguard us against these life-threatening challenges to some extent. Amid this crisis, the current comprehensive review highlights the present status of knowledge, our search for bacteria Achilles' heel, distinct molecular signaling that an opportunistic pathogen bestows to trespass the toxicity of antibiotics, and facile strategies and appealing therapeutic targets of novel drugs. Herein, we also discuss multidimensional strategies to combat antimicrobial resistance.
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Affiliation(s)
- Bikash Baral
- Department
of Biochemistry, University of Turku, Tykistökatu 6, Turku, Finland
| | - M. R. Mozafari
- Australasian
Nanoscience and Nanotechnology Initiative, 8054 Monash University LPO, Clayton, Victoria 3168, Australia
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Onyeabor M, Martinez R, Kurgan G, Wang X. Engineering transport systems for microbial production. ADVANCES IN APPLIED MICROBIOLOGY 2020; 111:33-87. [PMID: 32446412 DOI: 10.1016/bs.aambs.2020.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The rapid development in the field of metabolic engineering has enabled complex modifications of metabolic pathways to generate a diverse product portfolio. Manipulating substrate uptake and product export is an important research area in metabolic engineering. Optimization of transport systems has the potential to enhance microbial production of renewable fuels and chemicals. This chapter comprehensively reviews the transport systems critical for microbial production as well as current genetic engineering strategies to improve transport functions and thus production metrics. In addition, this chapter highlights recent advancements in engineering microbial efflux systems to enhance cellular tolerance to industrially relevant chemical stress. Lastly, future directions to address current technological gaps are discussed.
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Affiliation(s)
- Moses Onyeabor
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Rodrigo Martinez
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Gavin Kurgan
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Xuan Wang
- School of Life Sciences, Arizona State University, Tempe, AZ, United States.
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Atzori A, Malloci G, Cardamone F, Bosin A, Vargiu AV, Ruggerone P. Molecular Interactions of Carbapenem Antibiotics with the Multidrug Efflux Transporter AcrB of Escherichia coli. Int J Mol Sci 2020; 21:E860. [PMID: 32013182 PMCID: PMC7037162 DOI: 10.3390/ijms21030860] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 01/26/2020] [Indexed: 12/22/2022] Open
Abstract
The drug/proton antiporter AcrB, engine of the major efflux pump AcrAB(Z)-TolC of Escherichia coli and other bacteria, is characterized by its impressive ability to transport chemically diverse compounds, conferring a multi-drug resistance (MDR) phenotype. Although hundreds of small molecules are known to be AcrB substrates, only a few co-crystal structures are available to date. Computational methods have been therefore intensively employed to provide structural and dynamical fingerprints related to transport and inhibition of AcrB. In this work, we performed a systematic computational investigation to study the interaction between representative carbapenem antibiotics and AcrB. We focused on the interaction of carbapenems with the so-called distal pocket, a region known for its importance in binding inhibitors and substrates of AcrB. Our findings reveal how the different physico-chemical nature of these antibiotics is reflected on their binding preference for AcrB. The molecular-level information provided here could help design new antibiotics less susceptible to the efflux mechanism.
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Affiliation(s)
| | - Giuliano Malloci
- Department of Physics, University of Cagliari, 09042 Monserrato (CA), Italy; (A.A.); (F.C.); (A.B.); (P.R.)
| | | | | | - Attilio Vittorio Vargiu
- Department of Physics, University of Cagliari, 09042 Monserrato (CA), Italy; (A.A.); (F.C.); (A.B.); (P.R.)
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Havenga B, Ndlovu T, Clements T, Reyneke B, Waso M, Khan W. Exploring the antimicrobial resistance profiles of WHO critical priority list bacterial strains. BMC Microbiol 2019; 19:303. [PMID: 31870288 PMCID: PMC6929480 DOI: 10.1186/s12866-019-1687-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 12/17/2019] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND The antimicrobial resistance of clinical, environmental and control strains of the WHO "Priority 1: Critical group" organisms, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa to various classes of antibiotics, colistin and surfactin (biosurfactant) was determined. METHODS Acinetobacter baumannii was isolated from environmental samples and antibiotic resistance profiling was performed to classify the test organisms [A. baumannii (n = 6), P. aeruginosa (n = 5), E. coli (n = 7) and K. pneumoniae (n = 7)] as multidrug resistant (MDR) or extreme drug resistant (XDR). All the bacterial isolates (n = 25) were screened for colistin resistance and the mobilised colistin resistance (mcr) genes. Biosurfactants produced by Bacillus amyloliquefaciens ST34 were solvent extracted and characterised using ultra-performance liquid chromatography (UPLC) coupled to electrospray ionisation mass spectrometry (ESI-MS). The susceptibility of strains, exhibiting antibiotic and colistin resistance, to the crude surfactin extract (cell-free supernatant) was then determined. RESULTS Antibiotic resistance profiling classified four A. baumannii (67%), one K. pneumoniae (15%) and one P. aeruginosa (20%) isolate as XDR, with one E. coli (15%) and three K. pneumoniae (43%) strains classified as MDR. Many of the isolates [A. baumannii (25%), E. coli (80%), K. pneumoniae (100%) and P. aeruginosa (100%)] exhibited colistin resistance [minimum inhibitory concentrations (MICs) ≥ 4 mg/L]; however, only one E. coli strain isolated from a clinical environment harboured the mcr-1 gene. UPLC-MS analysis then indicated that the B. amyloliquefaciens ST34 produced C13-16 surfactin analogues, which were identified as Srf1 to Srf5. The crude surfactin extract (10.00 mg/mL) retained antimicrobial activity (100%) against the MDR, XDR and colistin resistant A. baumannii, P. aeruginosa, E. coli and K. pneumoniae strains. CONCLUSION Clinical, environmental and control strains of A. baumannii, P. aeruginosa, E. coli and K. pneumoniae exhibiting MDR and XDR profiles and colistin resistance, were susceptible to surfactin analogues, confirming that this lipopeptide shows promise for application in clinical settings.
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Affiliation(s)
- Benjamin Havenga
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602 South Africa
| | - Thando Ndlovu
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602 South Africa
| | - Tanya Clements
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602 South Africa
| | - Brandon Reyneke
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602 South Africa
| | - Monique Waso
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602 South Africa
| | - Wesaal Khan
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602 South Africa
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Multidrug Resistance in Neisseria gonorrhoeae: Identification of Functionally Important Residues in the MtrD Efflux Protein. mBio 2019; 10:mBio.02277-19. [PMID: 31744915 PMCID: PMC6867893 DOI: 10.1128/mbio.02277-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
With over 78 million new infections globally each year, gonorrhea remains a frustratingly common infection. Continuous development and spread of antimicrobial-resistant strains of Neisseria gonorrhoeae, the causative agent of gonorrhea, have posed a serious threat to public health. One of the mechanisms in N. gonorrhoeae involved in resistance to multiple drugs is performed by the MtrD multidrug resistance efflux pump. This study demonstrated that the MtrD pump has a broader substrate specificity than previously proposed and identified a cluster of residues important for drug binding and translocation. Additionally, a permeation pathway for the MtrD substrate progesterone actively moving through the protein was determined, revealing key interactions within the putative MtrD drug binding pockets. Identification of functionally important residues and substrate-protein interactions of the MtrD protein is crucial to develop future strategies for the treatment of multidrug-resistant gonorrhea. A key mechanism that Neisseria gonorrhoeae uses to achieve multidrug resistance is the expulsion of structurally different antimicrobials by the MtrD multidrug efflux protein. MtrD resembles the homologous Escherichia coli AcrB efflux protein with several common structural features, including an open cleft containing putative access and deep binding pockets proposed to interact with substrates. A highly discriminating N. gonorrhoeae strain, with the MtrD and NorM multidrug efflux pumps inactivated, was constructed and used to confirm and extend the substrate profile of MtrD to include 14 new compounds. The structural basis of substrate interactions with MtrD was interrogated by a combination of long-timescale molecular dynamics simulations and docking studies together with site-directed mutagenesis of selected residues. Of the MtrD mutants generated, only one (S611A) retained a wild-type (WT) resistance profile, while others (F136A, F176A, I605A, F610A, F612C, and F623C) showed reduced resistance to different antimicrobial compounds. Docking studies of eight MtrD substrates confirmed that many of the mutated residues play important nonspecific roles in binding to these substrates. Long-timescale molecular dynamics simulations of MtrD with its substrate progesterone showed the spontaneous binding of the substrate to the access pocket of the binding cleft and its subsequent penetration into the deep binding pocket, allowing the permeation pathway for a substrate through this important resistance mechanism to be identified. These findings provide a detailed picture of the interaction of MtrD with substrates that can be used as a basis for rational antibiotic and inhibitor design.
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Plant-derived secondary metabolites as the main source of efflux pump inhibitors and methods for identification. J Pharm Anal 2019; 10:277-290. [PMID: 32923005 PMCID: PMC7474127 DOI: 10.1016/j.jpha.2019.11.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/05/2019] [Accepted: 11/04/2019] [Indexed: 12/25/2022] Open
Abstract
The upsurge of multiple drug resistance (MDR) bacteria substantially diminishes the effectiveness of antibiotic arsenal and therefore intensifies the rate of therapeutic failure. The major factor in MDR is efflux pump-mediated resistance. A unique pump can make bacteria withstand a wide range of structurally diverse compounds. Therefore, their inhibition is a promising route to eliminate resistance phenomenon in bacteria. Phytochemicals are excellent alternatives as resistance-modifying agents. They can directly kill bacteria or interact with the crucial events of pathogenicity, thereby decreasing the ability of bacteria to develop resistance. Numerous botanicals display noteworthy efflux pumps inhibitory activities. Edible plants are of growing interest. Likewise, some plant families would be excellent sources of efflux pump inhibitors (EPIs) including Apocynaceae, Berberidaceae, Convolvulaceae, Cucurbitaceae, Fabaceae, Lamiaceae, and Zingiberaceae. Easily applicable methods for screening plant-derived EPIs include checkerboard synergy test, berberine uptake assay and ethidium bromide test. In silico high-throughput virtual detection can be evaluated as a criterion of excluding compounds with efflux substrate-like characteristics, thereby improving the selection process and extending the identification of EPIs. To ascertain the efflux activity inhibition, real-time PCR and quantitative mass spectrometry can be applied. This review emphasizes on efflux pumps and their roles in transmitting bacterial resistance and an update plant-derived EPIs and strategies for identification. Active efflux as the main resistance strategy in bacteria. Phytochemicals as promising alternatives against efflux pumps-mediated MDR. Herbals-based efflux pump inhibitors screening, the methods.
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Kobylka J, Kuth MS, Müller RT, Geertsma ER, Pos KM. AcrB: a mean, keen, drug efflux machine. Ann N Y Acad Sci 2019; 1459:38-68. [PMID: 31588569 DOI: 10.1111/nyas.14239] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/21/2019] [Accepted: 09/02/2019] [Indexed: 12/23/2022]
Abstract
Gram-negative bacteria are intrinsically resistant against cytotoxic substances by means of their outer membrane and a network of multidrug efflux systems, acting in synergy. Efflux pumps from various superfamilies with broad substrate preferences sequester and pump drugs across the inner membrane to supply the highly polyspecific and powerful tripartite resistance-nodulation-cell division (RND) efflux pumps with compounds to be extruded across the outer membrane barrier. In Escherichia coli, the tripartite efflux system AcrAB-TolC is the archetype RND multiple drug efflux pump complex. The homotrimeric inner membrane component acriflavine resistance B (AcrB) is the drug specificity and energy transduction center for the drug/proton antiport process. Drugs are bound and expelled via a cycle of mainly three consecutive states in every protomer, constituting a flexible alternating access channel system. This review recapitulates the molecular basis of drug and inhibitor binding, including mechanistic insights into drug efflux by AcrB. It also summarizes 17 years of mutational analysis of the gene acrB, reporting the effect of every substitution on the ability of E. coli to confer resistance toward antibiotics (http://goethe.link/AcrBsubstitutions). We emphasize the functional robustness of AcrB toward single-site substitutions and highlight regions that are more sensitive to perturbation.
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Affiliation(s)
- Jessica Kobylka
- Institute of Biochemistry, Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - Miriam S Kuth
- Institute of Biochemistry, Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - Reinke T Müller
- Institute of Biochemistry, Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - Eric R Geertsma
- Institute of Biochemistry, Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - Klaas M Pos
- Institute of Biochemistry, Goethe-University Frankfurt, Frankfurt am Main, Germany
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36
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Chetri S, Bhowmik D, Paul D, Pandey P, Chanda DD, Chakravarty A, Bora D, Bhattacharjee A. AcrAB-TolC efflux pump system plays a role in carbapenem non-susceptibility in Escherichia coli. BMC Microbiol 2019; 19:210. [PMID: 31488061 PMCID: PMC6727511 DOI: 10.1186/s12866-019-1589-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 08/29/2019] [Indexed: 11/21/2022] Open
Abstract
Background Efflux pump mediated antibiotic resistance is an unnoticed and undetected mechanism in clinical microbiology laboratory. RND efflux systems are known for aminoglycoside and tetracycline resistance whereas their role in carbapenem non-susceptibility is not established. The study was undertaken to investigate the role of efflux pump in providing resistance against carbapenems and their response against concentration gradient carbapenem stress on the transcriptional level of the AcrAB gene in the clinical isolates of Escherichia coli from a tertiary referral hospital of Northeast India. Results Out of 298 non-susceptible Escherichia coli isolates 98 isolates were found to have efflux pump mediated carbapenem non-susceptibility. Among them thirty-five were non carbapenemase producers and their expressional levels were verified using qRT-PCR under concentration gradient carbapenem stress. In this study, a strong correlation between ertapenem resistance and AcrA overexpression was observed which has not been reported previously. Further, it was observed that imipenem stress increased AcrB expression in Escherichia coli which holds the novelty of this study. Additionally, the transcription of AcrR was insistently increased which is much higher than the transcriptional level of AcrA under concentration gradient carbapenem stress condition. Conclusion The study established that AcrAB pump is a relevant antibiotic resistance determinant in bacterial pathogen, has an important role in developing resistance against carbapenem group of antibiotics. Electronic supplementary material The online version of this article (10.1186/s12866-019-1589-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Shiela Chetri
- Department of Microbiology, Assam University, Silchar, Assam, India
| | | | - Deepjyoti Paul
- Department of Microbiology, Assam University, Silchar, Assam, India
| | - Piyush Pandey
- Department of Microbiology, Assam University, Silchar, Assam, India
| | | | - Atanu Chakravarty
- Department of Microbiology, Silchar Medical College and Hospital, Silchar, India
| | - Debajyoti Bora
- Department of Statistics, Dibrugarh University, Dibrugarh, India
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37
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Shaheen A, Afridi WA, Mahboob S, Sana M, Zeeshan N, Ismat F, Mirza O, Iqbal M, Rahman M. Reserpine Is the New Addition into the Repertoire of AcrB Efflux Pump Inhibitors. Mol Biol 2019. [DOI: 10.1134/s0026893319040113] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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38
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Jelinkova P, Mazumdar A, Sur VP, Kociova S, Dolezelikova K, Jimenez AMJ, Koudelkova Z, Mishra PK, Smerkova K, Heger Z, Vaculovicova M, Moulick A, Adam V. Nanoparticle-drug conjugates treating bacterial infections. J Control Release 2019; 307:166-185. [DOI: 10.1016/j.jconrel.2019.06.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 06/10/2019] [Accepted: 06/12/2019] [Indexed: 12/19/2022]
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39
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Lamut A, Peterlin Mašič L, Kikelj D, Tomašič T. Efflux pump inhibitors of clinically relevant multidrug resistant bacteria. Med Res Rev 2019; 39:2460-2504. [PMID: 31004360 DOI: 10.1002/med.21591] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 03/31/2019] [Accepted: 04/02/2019] [Indexed: 12/29/2022]
Abstract
Bacterial infections are an increasingly serious issue worldwide. The inability of existing therapies to treat multidrug-resistant pathogens has been recognized as an important challenge of the 21st century. Efflux pumps are important in both intrinsic and acquired bacterial resistance and identification of small molecule efflux pump inhibitors (EPIs), capable of restoring the effectiveness of available antibiotics, is an active research field. In the last two decades, much effort has been made to identify novel EPIs. However, none of them has so far been approved for therapeutic use. In this article, we explore different structural families of currently known EPIs for multidrug resistance efflux systems in the most extensively studied pathogens (NorA in Staphylococcus aureus, AcrAB-TolC in Escherichia coli, and MexAB-OprM in Pseudomonas aeruginosa). Both synthetic and natural compounds are described, with structure-activity relationship studies and optimization processes presented systematically for each family individually. In vitro activities against selected test strains are presented in a unifying manner for all the EPIs described, together with the most important toxicity, pharmacokinetic and in vivo efficacy data. A critical evaluation of lead-likeness characteristics and the potential for clinical development of the most promising inhibitors of the three efflux systems is described. This overview of EPIs is a good starting point for the identification of novel effective antibacterial drugs.
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Affiliation(s)
- Andraž Lamut
- Chair of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - Lucija Peterlin Mašič
- Chair of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - Danijel Kikelj
- Chair of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - Tihomir Tomašič
- Chair of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
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40
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Williams TL, Senft SL, Yeo J, Martín-Martínez FJ, Kuzirian AM, Martin CA, DiBona CW, Chen CT, Dinneen SR, Nguyen HT, Gomes CM, Rosenthal JJC, MacManes MD, Chu F, Buehler MJ, Hanlon RT, Deravi LF. Dynamic pigmentary and structural coloration within cephalopod chromatophore organs. Nat Commun 2019; 10:1004. [PMID: 30824708 PMCID: PMC6397165 DOI: 10.1038/s41467-019-08891-x] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 01/23/2019] [Indexed: 01/08/2023] Open
Abstract
Chromatophore organs in cephalopod skin are known to produce ultra-fast changes in appearance for camouflage and communication. Light-scattering pigment granules within chromatocytes have been presumed to be the sole source of coloration in these complex organs. We report the discovery of structural coloration emanating in precise register with expanded pigmented chromatocytes. Concurrently, using an annotated squid chromatophore proteome together with microscopy, we identify a likely biochemical component of this reflective coloration as reflectin proteins distributed in sheath cells that envelop each chromatocyte. Additionally, within the chromatocytes, where the pigment resides in nanostructured granules, we find the lens protein Ω- crystallin interfacing tightly with pigment molecules. These findings offer fresh perspectives on the intricate biophotonic interplay between pigmentary and structural coloration elements tightly co-located within the same dynamic flexible organ - a feature that may help inspire the development of new classes of engineered materials that change color and pattern.
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Affiliation(s)
- Thomas L Williams
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
| | - Stephen L Senft
- The Eugene Bell Center, The Marine Biological Laboratory, Woods Hole, MA, 02543, USA
| | - Jingjie Yeo
- Department of Biomedical Engineering, Tufts University, Medford, MA, 02155, USA.,Laboratory for Atomistic and Molecular Mechanics (LAMM), Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Institute of High Performance Computing, A*STAR, Singapore, 138632, Singapore
| | - Francisco J Martín-Martínez
- Laboratory for Atomistic and Molecular Mechanics (LAMM), Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Alan M Kuzirian
- The Eugene Bell Center, The Marine Biological Laboratory, Woods Hole, MA, 02543, USA
| | - Camille A Martin
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
| | - Christopher W DiBona
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
| | - Chun-Teh Chen
- Laboratory for Atomistic and Molecular Mechanics (LAMM), Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Sean R Dinneen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
| | - Hieu T Nguyen
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Conor M Gomes
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
| | - Joshua J C Rosenthal
- The Eugene Bell Center, The Marine Biological Laboratory, Woods Hole, MA, 02543, USA
| | - Matthew D MacManes
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Feixia Chu
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Markus J Buehler
- Laboratory for Atomistic and Molecular Mechanics (LAMM), Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Roger T Hanlon
- The Eugene Bell Center, The Marine Biological Laboratory, Woods Hole, MA, 02543, USA.
| | - Leila F Deravi
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA.
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41
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Anes J, Sivasankaran SK, Muthappa DM, Fanning S, Srikumar S. Exposure to Sub-inhibitory Concentrations of the Chemosensitizer 1-(1-Naphthylmethyl)-Piperazine Creates Membrane Destabilization in Multi-Drug Resistant Klebsiella pneumoniae. Front Microbiol 2019; 10:92. [PMID: 30814979 PMCID: PMC6381021 DOI: 10.3389/fmicb.2019.00092] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 01/16/2019] [Indexed: 01/23/2023] Open
Abstract
Antimicrobial efflux is one of the important mechanisms causing multi-drug resistance (MDR) in bacteria. Chemosensitizers like 1-(1-naphthylmethyl)-piperazine (NMP) can inhibit an efflux pump and therefore can overcome MDR. However, secondary effects of NMP other than efflux pump inhibition are rarely investigated. Here, using phenotypic assays, phenotypic microarray and transcriptomic assays we show that NMP creates membrane destabilization in MDR Klebsiella pneumoniae MGH 78578 strain. The NMP mediated membrane destabilization activity was measured using β-lactamase activity, membrane potential alteration studies, and transmission electron microscopy assays. Results from both β-lactamase and membrane potential alteration studies shows that both outer and inner membranes are destabilized in NMP exposed K. pneumoniae MGH 78578 cells. Phenotypic Microarray and RNA-seq were further used to elucidate the metabolic and transcriptional signals underpinning membrane destabilization. Membrane destabilization happens as early as 15 min post-NMP treatment. Our RNA-seq data shows that many genes involved in envelope stress response were differentially regulated in the NMP treated cells. Up-regulation of genes encoding the envelope stress response and repair systems show the distortion in membrane homeostasis during survival in an environment containing sub-inhibitory concentration of NMP. In addition, the lsr operon encoding the production of autoinducer-2 responsible for biofilm production was down-regulated resulting in reduced biofilm formation in NMP treated cells, a phenotype confirmed by crystal violet-based assays. We postulate that the early membrane disruption leads to destabilization of inner membrane potential, impairing ATP production and consequently resulting in efflux pump inhibition.
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Affiliation(s)
- João Anes
- School of Public Health, Physiotherapy and Sports Science, Centre for Food Safety, Science Centre South, University College Dublin, Dublin, Ireland
| | | | - Dechamma M Muthappa
- School of Public Health, Physiotherapy and Sports Science, Centre for Food Safety, Science Centre South, University College Dublin, Dublin, Ireland
| | - Séamus Fanning
- School of Public Health, Physiotherapy and Sports Science, Centre for Food Safety, Science Centre South, University College Dublin, Dublin, Ireland.,Institute for Global Food Security, Queen's University Belfast, Belfast, United Kingdom
| | - Shabarinath Srikumar
- School of Public Health, Physiotherapy and Sports Science, Centre for Food Safety, Science Centre South, University College Dublin, Dublin, Ireland
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42
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Drug combinations: a strategy to extend the life of antibiotics in the 21st century. Nat Rev Microbiol 2019; 17:141-155. [PMID: 30683887 DOI: 10.1038/s41579-018-0141-x] [Citation(s) in RCA: 436] [Impact Index Per Article: 87.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 11/22/2018] [Indexed: 01/03/2023]
Abstract
Antimicrobial resistance threatens a resurgence of life-threatening bacterial infections and the potential demise of many aspects of modern medicine. Despite intensive drug discovery efforts, no new classes of antibiotics have been developed into new medicines for decades, in large part owing to the stringent chemical, biological and pharmacological requisites for effective antibiotic drugs. Combinations of antibiotics and of antibiotics with non-antibiotic activity-enhancing compounds offer a productive strategy to address the widespread emergence of antibiotic-resistant strains. In this Review, we outline a theoretical and practical framework for the development of effective antibiotic combinations.
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43
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Darzynkiewicz ZM, Green AT, Abdali N, Hazel A, Fulton RL, Kimball J, Gryczynski Z, Gumbart JC, Parks JM, Smith JC, Zgurskaya HI. Identification of Binding Sites for Efflux Pump Inhibitors of the AcrAB-TolC Component AcrA. Biophys J 2019; 116:648-658. [PMID: 30691677 DOI: 10.1016/j.bpj.2019.01.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 01/06/2019] [Accepted: 01/07/2019] [Indexed: 01/02/2023] Open
Abstract
The overexpression of multidrug efflux pumps is an important mechanism of clinical resistance in Gram-negative bacteria. Recently, four small molecules were discovered that inhibit efflux in Escherichia coli and interact with the AcrAB-TolC efflux pump component AcrA. However, the binding site(s) for these molecules was not determined. Here, we combine ensemble docking and molecular dynamics simulations with tryptophan fluorescence spectroscopy, site-directed mutagenesis, and antibiotic susceptibility assays to probe binding sites and effects of binding of these molecules. We conclude that clorobiocin and SLU-258 likely bind at a site located between the lipoyl and β-barrel domains of AcrA.
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Affiliation(s)
| | - Adam T Green
- UT/ORNL Center for Molecular Biophysics, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee; Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, Tennessee
| | - Narges Abdali
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma
| | - Anthony Hazel
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia
| | - Ronnie L Fulton
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma
| | - Joseph Kimball
- Department of Physics and Astronomy, Texas Christian University, Fort Worth, Texas
| | - Zygmunt Gryczynski
- Department of Physics and Astronomy, Texas Christian University, Fort Worth, Texas; Department of Microbiology, Immunology, and Genetics, University of North Texas Health Science Center, Fort Worth, Texas
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia
| | - Jerry M Parks
- UT/ORNL Center for Molecular Biophysics, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee; Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, Tennessee
| | - Jeremy C Smith
- UT/ORNL Center for Molecular Biophysics, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee; Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, Tennessee; Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee
| | - Helen I Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma.
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44
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Escherichia coli as a host for metabolic engineering. Metab Eng 2018; 50:16-46. [DOI: 10.1016/j.ymben.2018.04.008] [Citation(s) in RCA: 181] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 04/11/2018] [Accepted: 04/12/2018] [Indexed: 12/21/2022]
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45
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Otoupal PB, Chatterjee A. CRISPR Gene Perturbations Provide Insights for Improving Bacterial Biofuel Tolerance. Front Bioeng Biotechnol 2018; 6:122. [PMID: 30234107 PMCID: PMC6131188 DOI: 10.3389/fbioe.2018.00122] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 08/14/2018] [Indexed: 11/13/2022] Open
Abstract
Economically-viable biofuel production is often limited by low levels of microbial tolerance to high biofuel concentrations. Here we demonstrate the first application of deactivated CRISPR perturbations of gene expression to improve Escherichia coli biofuel tolerance. We construct a library of 31 unique CRISPR inhibitions and activations of gene expression in E. coli and explore their impacts on growth during 10 days of exposure to n-butanol and n-hexane. We show that perturbation of metabolism and membrane-related genes induces the greatest impacts on growth in n-butanol, as does perturbation of redox-related genes in n-hexanes. We identify uncharacterized genes yjjZ and yehS with strong potential for improving tolerance to both biofuels. Perturbations demonstrated significant temporal dependencies, suggesting that rationally designing time-sensitive gene circuits can optimize tolerance. We also introduce a sgRNA-specific hyper-mutator phenotype (~2,600-fold increase) into our perturbation strains using error-prone Pol1. We show that despite this change, strains exhibited similar growth phenotypes in n-butanol as before, demonstrating the robustness of CRISPR perturbations during prolonged use. Collectively, these results demonstrate the potential of CRISPR manipulation of gene expression for improving biofuel tolerance and provide constructive starting points for optimization of biofuel producing microorganisms.
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Affiliation(s)
- Peter B Otoupal
- Department of Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, CO, United States
| | - Anushree Chatterjee
- Department of Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, CO, United States.,BioFrontiers Institute, University of Colorado at Boulder, Boulder, CO, United States
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46
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Zwama M, Yamaguchi A. Molecular mechanisms of AcrB-mediated multidrug export. Res Microbiol 2018; 169:372-383. [PMID: 29807096 DOI: 10.1016/j.resmic.2018.05.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/07/2018] [Accepted: 05/16/2018] [Indexed: 10/16/2022]
Abstract
The over-expression of multidrug efflux pumps belonging to the Resistance-Nodulation-Division (RND) superfamily is one of the main causes of multidrug-resistance (MDR) in Gram-negative pathogenic bacteria. AcrB is the most thoroughly studied RND transporter and has functioned as a model for our understanding of efflux-mediated MDR. This multidrug-exporter can recognize and transport a wide range of structurally unrelated compounds (including antibiotics, dyes, bile salts and detergents), while it shows a strict inhibitor specificity. Here we discuss our current knowledge of AcrB, and include recent advances, regarding its structure, mechanism of drug transport, substrate recognition, different intramolecular entry pathways and the drug export driven by remote conformational coupling.
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Affiliation(s)
- Martijn Zwama
- Laboratory of Cell Membrane Structural Biology, Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka, 567-0047, Japan; Department of Biomolecular Science and Regulation, Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka, 567-0047, Japan; Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Akihito Yamaguchi
- Laboratory of Cell Membrane Structural Biology, Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka, 567-0047, Japan.
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47
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Nitrothiophene carboxamides, a novel narrow spectrum antibacterial series: Mechanism of action and Efficacy. Sci Rep 2018; 8:7263. [PMID: 29740005 PMCID: PMC5940854 DOI: 10.1038/s41598-018-25407-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 04/20/2018] [Indexed: 12/24/2022] Open
Abstract
The mechanism of efflux is a tour-de-force in the bacterial armoury that has thwarted the development of novel antibiotics. We report the discovery of a novel chemical series with potent antibacterial properties that was engineered to overcome efflux liability. Compounds liable to efflux specifically via the Resistance Nodulation and cell Division (RND) pump, AcrAB-TolC were chosen for a hit to lead progression. Using structure-based design, the compounds were optimised to lose their binding to the efflux pump, thereby making them potent on wild-type bacteria. We discovered these compounds to be pro-drugs that require activation in E. coli by specific bacterial nitroreductases NfsA and NfsB. Hit to lead chemistry led to the generation of compounds that were potent on wild-type and multi-drug resistant clinical isolates of E. coli, Shigella spp., and Salmonella spp. These compounds are bactericidal and efficacious in a mouse thigh infection model.
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48
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Matsunaga Y, Yamane T, Terada T, Moritsugu K, Fujisaki H, Murakami S, Ikeguchi M, Kidera A. Energetics and conformational pathways of functional rotation in the multidrug transporter AcrB. eLife 2018; 7:31715. [PMID: 29506651 PMCID: PMC5839741 DOI: 10.7554/elife.31715] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Accepted: 02/12/2018] [Indexed: 12/31/2022] Open
Abstract
The multidrug transporter AcrB transports a broad range of drugs out of the cell by means of the proton-motive force. The asymmetric crystal structure of trimeric AcrB suggests a functionally rotating mechanism for drug transport. Despite various supportive forms of evidence from biochemical and simulation studies for this mechanism, the link between the functional rotation and proton translocation across the membrane remains elusive. Here, calculating the minimum free energy pathway of the functional rotation for the complete AcrB trimer, we describe the structural and energetic basis behind the coupling between the functional rotation and the proton translocation at atomic resolution. Free energy calculations show that protonation of Asp408 in the transmembrane portion of the drug-bound protomer drives the functional rotation. The conformational pathway identifies vertical shear motions among several transmembrane helices, which regulate alternate access of water in the transmembrane as well as peristaltic motions that pump drugs in the periplasm.
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Affiliation(s)
- Yasuhiro Matsunaga
- RIKEN Advanced Institute for Computational Science, Kobe, Japan.,JST PRESTO, Kawaguchi, Japan
| | - Tsutomu Yamane
- Graduate School of Medical Life Science, Yokohama City University, Yokohama, Japan
| | - Tohru Terada
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Kei Moritsugu
- Graduate School of Medical Life Science, Yokohama City University, Yokohama, Japan
| | | | - Satoshi Murakami
- Graduate School of Bioscience & Biotechnology, Tokyo Institute of Technology, Yokohama, Japan
| | - Mitsunori Ikeguchi
- Graduate School of Medical Life Science, Yokohama City University, Yokohama, Japan
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49
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Vargiu AV, Ramaswamy VK, Malloci G, Malvacio I, Atzori A, Ruggerone P. Computer simulations of the activity of RND efflux pumps. Res Microbiol 2018; 169:384-392. [PMID: 29407044 DOI: 10.1016/j.resmic.2017.12.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 12/01/2017] [Accepted: 12/05/2017] [Indexed: 12/25/2022]
Abstract
The putative mechanism by which bacterial RND-type multidrug efflux pumps recognize and transport their substrates is a complex and fascinating enigma of structural biology. How a single protein can recognize a huge number of unrelated compounds and transport them through one or just a few mechanisms is an amazing feature not yet completely unveiled. The appearance of cooperativity further complicates the understanding of structure-dynamics-activity relationships in these complex machineries. Experimental techniques may have limited access to the molecular determinants and to the energetics of key processes regulating the activity of these pumps. Computer simulations are a complementary approach that can help unveil these features and inspire new experiments. Here we review recent computational studies that addressed the various molecular processes regulating the activity of RND efflux pumps.
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Affiliation(s)
- Attilio Vittorio Vargiu
- Department of Physics, University of Cagliari, Cittadella Universitaria, S.P. Monserrato-Sestu km 0.700, 09042 Monserrato (CA), Italy.
| | - Venkata Krishnan Ramaswamy
- Department of Physics, University of Cagliari, Cittadella Universitaria, S.P. Monserrato-Sestu km 0.700, 09042 Monserrato (CA), Italy
| | - Giuliano Malloci
- Department of Physics, University of Cagliari, Cittadella Universitaria, S.P. Monserrato-Sestu km 0.700, 09042 Monserrato (CA), Italy
| | - Ivana Malvacio
- Department of Physics, University of Cagliari, Cittadella Universitaria, S.P. Monserrato-Sestu km 0.700, 09042 Monserrato (CA), Italy
| | - Alessio Atzori
- Department of Physics, University of Cagliari, Cittadella Universitaria, S.P. Monserrato-Sestu km 0.700, 09042 Monserrato (CA), Italy
| | - Paolo Ruggerone
- Department of Physics, University of Cagliari, Cittadella Universitaria, S.P. Monserrato-Sestu km 0.700, 09042 Monserrato (CA), Italy.
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Cacciotto P, Ramaswamy VK, Malloci G, Ruggerone P, Vargiu AV. Molecular Modeling of Multidrug Properties of Resistance Nodulation Division (RND) Transporters. Methods Mol Biol 2018; 1700:179-219. [PMID: 29177832 DOI: 10.1007/978-1-4939-7454-2_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Efflux pumps of the resistance nodulation division (RND) superfamily are among the major contributors to intrinsic and acquired multidrug resistance in Gram-negative bacteria. Structural information on AcrAB-TolC and MexAB-OprM, major efflux pumps of Escherichia coli and Pseudomonas aeruginosa respectively, boosted intensive research aimed at understanding the molecular mechanisms ruling the active extrusion processes. In particular, several studies were devoted to the understanding of the determinants behind the extraordinary broad specificity of the RND transporters AcrB and MexB. In this chapter, we discuss the ever-growing role computational methods have been playing in deciphering key structural and dynamical features of these transporters and of their interaction with substrates and inhibitors. We further discuss and illustrate examples from our lab of how molecular docking, homology modeling, all-atom molecular dynamics simulations and in silico free energy estimations can all together give precious insights into the processes of recognition and extrusion of substrates, as well as on the possible inhibition strategies.
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Affiliation(s)
- Pierpaolo Cacciotto
- Department of Physics, University of Cagliari, s.p. 8, 09042, Monserrato, CA, Italy
| | - Venkata K Ramaswamy
- Department of Physics, University of Cagliari, s.p. 8, 09042, Monserrato, CA, Italy
| | - Giuliano Malloci
- Department of Physics, University of Cagliari, s.p. 8, 09042, Monserrato, CA, Italy
| | - Paolo Ruggerone
- Department of Physics, University of Cagliari, s.p. 8, 09042, Monserrato, CA, Italy
| | - Attilio V Vargiu
- Department of Physics, University of Cagliari, s.p. 8, 09042, Monserrato, CA, Italy.
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