101
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Lee JTY, Wang G, Tam YT, Tam C. Membrane-Active Epithelial Keratin 6A Fragments (KAMPs) Are Unique Human Antimicrobial Peptides with a Non-αβ Structure. Front Microbiol 2016; 7:1799. [PMID: 27891122 PMCID: PMC5105358 DOI: 10.3389/fmicb.2016.01799] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 10/26/2016] [Indexed: 11/23/2022] Open
Abstract
Antibiotic resistance is a pressing global health problem that threatens millions of lives each year. Natural antimicrobial peptides and their synthetic derivatives, including peptoids and peptidomimetics, are promising candidates as novel antibiotics. Recently, the C-terminal glycine-rich fragments of human epithelial keratin 6A were found to have bactericidal and cytoprotective activities. Here, we used an improved 2-dimensional NMR method coupled with a new protocol for structural refinement by low temperature simulated annealing to characterize the solution structure of these kerain-derived antimicrobial peptides (KAMPs). Two specific KAMPs in complex with membrane mimicking sodium dodecyl sulfate (SDS) micelles displayed amphipathic conformations with only local bends and turns, and a central 10-residue glycine-rich hydrophobic strip that is central to bactericidal activity. To our knowledge, this is the first report of non-αβ structure for human antimicrobial peptides. Direct observation of Staphylococcus aureus and Pseudomonas aeruginosa by scanning and transmission electron microscopy showed that KAMPs deformed bacterial cell envelopes and induced pore formation. Notably, in competitive binding experiments, KAMPs demonstrated binding affinities to LPS and LTA that did not correlate with their bactericidal activities, suggesting peptide-LPS and peptide-LTA interactions are less important in their mechanisms of action. Moreover, immunoprecipitation of KAMPs-bacterial factor complexes indicated that membrane surface lipoprotein SlyB and intracellular machineries NQR sodium pump and ribosomes are potential molecular targets for the peptides. Results of this study improve our understanding of the bactericidal function of epithelial cytokeratin fragments, and highlight an unexplored class of human antimicrobial peptides, which may serve as non-αβ peptide scaffolds for the design of novel peptide-based antibiotics.
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Affiliation(s)
- Judy T Y Lee
- Department of Ophthalmic Research, Cole Eye Institute and Lerner Research Institute, Cleveland Clinic Cleveland, OH, USA
| | - Guangshun Wang
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center Omaha, NE, USA
| | - Yu Tong Tam
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison Madison, WI, USA
| | - Connie Tam
- Department of Ophthalmic Research, Cole Eye Institute and Lerner Research Institute, Cleveland ClinicCleveland, OH, USA; Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve UniversityCleveland, OH, USA
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102
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Tillotson GS. Trojan Horse Antibiotics-A Novel Way to Circumvent Gram-Negative Bacterial Resistance? Infect Dis (Lond) 2016; 9:45-52. [PMID: 27773991 PMCID: PMC5063921 DOI: 10.4137/idrt.s31567] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 09/13/2016] [Accepted: 09/18/2016] [Indexed: 11/16/2022] Open
Abstract
Antibiotic resistance has been emerged as a major global health problem. In particular, gram-negative species pose a significant clinical challenge as bacteria develop or acquire more resistance mechanisms. Often, these bacteria possess multiple resistance mechanisms, thus nullifying most of the major classes of drugs. Novel approaches to this issue are urgently required. However, the challenges of developing new agents are immense. Introducing novel agents is fraught with hurdles, thus adapting known antibiotic classes by altering their chemical structure could be a way forward. A chemical addition to existing antibiotics known as a siderophore could be a solution to the gram-negative resistance issue. Siderophore molecules rely on the bacterial innate need for iron ions and thus can utilize a Trojan Horse approach to gain access to the bacterial cell. The current approaches to using this potential method are reviewed.
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103
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Huwaitat R, McCloskey AP, Gilmore BF, Laverty G. Potential strategies for the eradication of multidrug-resistant Gram-negative bacterial infections. Future Microbiol 2016; 11:955-72. [PMID: 27357521 DOI: 10.2217/fmb-2016-0035] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Antimicrobial resistance is one of the leading threats to society. The increasing burden of multidrug-resistant Gram-negative infection is particularly concerning as such bacteria are demonstrating resistance to nearly all currently licensed therapies. Various strategies have been hypothesized to treat multidrug-resistant Gram-negative infections including: targeting the Gram-negative outer membrane; neutralization of lipopolysaccharide; inhibition of bacterial efflux pumps and prevention of protein folding. Silver and silver nanoparticles, fusogenic liposomes and nanotubes are potential strategies for extending the activity of licensed, Gram-positive selective, antibiotics to Gram-negatives. This may serve as a strategy to fill the current void in pharmaceutical development in the short term. This review outlines the most promising strategies that could be implemented to solve the threat of multidrug-resistant Gram-negative infections.
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Affiliation(s)
- Rawan Huwaitat
- Biofunctional Nanomaterials Group, School of Pharmacy, Queens University of Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Alice P McCloskey
- Biofunctional Nanomaterials Group, School of Pharmacy, Queens University of Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Brendan F Gilmore
- Biofunctional Nanomaterials Group, School of Pharmacy, Queens University of Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Garry Laverty
- Biofunctional Nanomaterials Group, School of Pharmacy, Queens University of Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK
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104
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Joo HS, Fu CI, Otto M. Bacterial strategies of resistance to antimicrobial peptides. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150292. [PMID: 27160595 PMCID: PMC4874390 DOI: 10.1098/rstb.2015.0292] [Citation(s) in RCA: 213] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2016] [Indexed: 02/06/2023] Open
Abstract
Antimicrobial peptides (AMPs) are a key component of the host's innate immune system, targeting invasive and colonizing bacteria. For successful survival and colonization of the host, bacteria have a series of mechanisms to interfere with AMP activity, and AMP resistance is intimately connected with the virulence potential of bacterial pathogens. In particular, because AMPs are considered as potential novel antimicrobial drugs, it is vital to understand bacterial AMP resistance mechanisms. This review gives a comparative overview of Gram-positive and Gram-negative bacterial strategies of resistance to various AMPs, such as repulsion or sequestration by bacterial surface structures, alteration of membrane charge or fluidity, degradation and removal by efflux pumps.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'.
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Affiliation(s)
- Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Chih-Iung Fu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
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105
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Joo HS, Fu CI, Otto M. Bacterial strategies of resistance to antimicrobial peptides. Philos Trans R Soc Lond B Biol Sci 2016. [PMID: 27160595 DOI: 10.1098/rstb.2015.0292.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Antimicrobial peptides (AMPs) are a key component of the host's innate immune system, targeting invasive and colonizing bacteria. For successful survival and colonization of the host, bacteria have a series of mechanisms to interfere with AMP activity, and AMP resistance is intimately connected with the virulence potential of bacterial pathogens. In particular, because AMPs are considered as potential novel antimicrobial drugs, it is vital to understand bacterial AMP resistance mechanisms. This review gives a comparative overview of Gram-positive and Gram-negative bacterial strategies of resistance to various AMPs, such as repulsion or sequestration by bacterial surface structures, alteration of membrane charge or fluidity, degradation and removal by efflux pumps.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'.
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Affiliation(s)
- Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Chih-Iung Fu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
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106
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Enzymes required for the biosynthesis of N-formylated sugars. Curr Opin Struct Biol 2016; 41:1-9. [PMID: 27209114 DOI: 10.1016/j.sbi.2016.04.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 04/12/2016] [Accepted: 04/13/2016] [Indexed: 12/25/2022]
Abstract
The N-formyltransferases, also known as transformylases, play key roles in de novo purine biosynthesis where they catalyze the transfer of formyl groups to primary amine acceptors. These enzymes require N10-formyltetrahydrofolate for activity. Due to their biological importance they have been extensively investigated for many years, and they are still serving as targets for antifolate drug design. Most of our understanding of the N-formyltransferases has been derived from these previous studies. It is now becoming increasingly apparent, however, that N-formylation also occurs on some amino sugars found on the O-antigens of pathogenic bacteria. This review focuses on recent developments in the biochemical and structural characterization of the sugar N-formyltransferases.
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107
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Antibiotic failure mediated by a resistant subpopulation in Enterobacter cloacae. Nat Microbiol 2016; 1:16053. [PMID: 27572838 DOI: 10.1038/nmicrobiol.2016.53] [Citation(s) in RCA: 145] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 03/22/2016] [Indexed: 12/28/2022]
Abstract
Antibiotic resistance is a major public health threat, further complicated by unexplained treatment failures caused by bacteria that appear antibiotic susceptible. We describe an Enterobacter cloacae isolate harbouring a minor subpopulation that is highly resistant to the last-line antibiotic colistin. This subpopulation was distinct from persisters, became predominant in colistin, returned to baseline after colistin removal and was dependent on the histidine kinase PhoQ. During murine infection, but in the absence of colistin, innate immune defences led to an increased frequency of the resistant subpopulation, leading to inefficacy of subsequent colistin therapy. An isolate with a lower-frequency colistin-resistant subpopulation similarly caused treatment failure but was misclassified as susceptible by current diagnostics once cultured outside the host. These data demonstrate the ability of low-frequency bacterial subpopulations to contribute to clinically relevant antibiotic resistance, elucidating an enigmatic cause of antibiotic treatment failure and highlighting the critical need for more sensitive diagnostics.
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108
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Mingeot-Leclercq MP, Décout JL. Bacterial lipid membranes as promising targets to fight antimicrobial resistance, molecular foundations and illustration through the renewal of aminoglycoside antibiotics and emergence of amphiphilic aminoglycosides. MEDCHEMCOMM 2016. [DOI: 10.1039/c5md00503e] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Membrane anionic lipids as attractive targets in the design of amphiphilic antibacterial drugs active against resistant bacteria: molecular foundations and examples.
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Affiliation(s)
- Marie-Paule Mingeot-Leclercq
- Louvain Drug Research Institute
- Université catholique de Louvain
- Unité de Pharmacologie Cellulaire et Moléculaire
- Brussels
- Belgium
| | - Jean-Luc Décout
- Département de Pharmacochimie Moléculaire
- Université Grenoble Alpes/CNRS
- UMR 5063
- ICMG FR 2607
- F-38041 Grenoble
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109
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Toropova MA, Veselinović AM, Veselinović JB, Stojanović DB, Toropov AA. QSAR modeling of the antimicrobial activity of peptides as a mathematical function of a sequence of amino acids. Comput Biol Chem 2015; 59 Pt A:126-30. [DOI: 10.1016/j.compbiolchem.2015.09.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 08/04/2015] [Accepted: 09/15/2015] [Indexed: 01/29/2023]
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110
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M F, S PBT, D EP, F XE, Rosin eacute a ADP, Ana AEATB, S iacute lvia RSM, Margarete AFS, C eacute lia ADM, Hil aacute rio CM, Rosin eacute a ADP, Ana AEATB, S iacute lvia RSM, Margarete AFS, C eacute lia ADM, Hil aacute rio CM. In vitro antibacterial activity of Baillonella toxisperma (Pierre) extracts against Staphylococcus aureus, Salmonella typhi, Proteus mirabilis and Bacillus cereus F3748. ACTA ACUST UNITED AC 2015. [DOI: 10.5897/ajmr2015.7656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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111
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Kozić M, Vukičević D, Simunić J, Rončević T, Antcheva N, Tossi A, Juretić D. Predicting the Minimal Inhibitory Concentration for Antimicrobial Peptides with Rana-Box Domain. J Chem Inf Model 2015; 55:2275-87. [PMID: 26332863 DOI: 10.1021/acs.jcim.5b00161] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The global spreading of multidrug resistance has motivated the search for new antibiotic classes including different types of antimicrobial peptides (AMPs). Computational methods for predicting activity in terms of the minimal inhibitory concentration (MIC) of AMPs can facilitate "in silico" design and reduce the cost of synthesis and testing. We have used an original method for separating training and test data sets, both of which contain the sequences and measured MIC values of non-homologous anuran peptides having the Rana-box disulfide motif at their C-terminus. Using a more flexible profiling methodology (sideways asymmetry moment, SAM) than the standard hydrophobic moment, we have developed a two-descriptor model to predict the bacteriostatic activity of Rana-box peptides against Gram-negative bacteria--the first multilinear quantitative structure-activity relationship model capable of predicting MIC values for AMPs of widely different lengths and low identity using such a small number of descriptors. Maximal values for SAMs, as defined and calculated in our method, furthermore offer new structural insight into how different segments of a peptide contribute to its bacteriostatic activity, and this work lays the foundations for the design of active artificial AMPs with this type of disulfide bridge.
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Affiliation(s)
- Mara Kozić
- Institute of Integrative Biology, University of Liverpool , Liverpool L69 7ZB, U.K
| | - Damir Vukičević
- Faculty of Science, University of Split , 21000 Split, Croatia
| | - Juraj Simunić
- Mediterranean Institute for Life Sciences , 21000 Split, Croatia
| | | | - Nikolinka Antcheva
- Department of Life Sciences, University of Trieste , 34127 Trieste, Italy
| | - Alessandro Tossi
- Department of Life Sciences, University of Trieste , 34127 Trieste, Italy
| | - Davor Juretić
- Faculty of Science, University of Split , 21000 Split, Croatia
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112
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Kubicek-Sutherland JZ, Heithoff DM, Ersoy SC, Shimp WR, House JK, Marth JD, Smith JW, Mahan MJ. Host-dependent Induction of Transient Antibiotic Resistance: A Prelude to Treatment Failure. EBioMedicine 2015; 2:1169-78. [PMID: 26501114 PMCID: PMC4588393 DOI: 10.1016/j.ebiom.2015.08.012] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 07/31/2015] [Accepted: 08/05/2015] [Indexed: 01/03/2023] Open
Abstract
Current antibiotic testing does not include the potential influence of host cell environment on microbial susceptibility and antibiotic resistance, hindering appropriate therapeutic intervention. We devised a strategy to identify the presence of host–pathogen interactions that alter antibiotic efficacy in vivo. Our findings revealed a bacterial mechanism that promotes antibiotic resistance in vivo at concentrations of drug that far exceed dosages determined by standardized antimicrobial testing. This mechanism has escaped prior detection because it is reversible and operates within a subset of host tissues and cells. Bacterial pathogens are thereby protected while their survival promotes the emergence of permanent drug resistance. This host-dependent mechanism of transient antibiotic resistance is applicable to multiple pathogens and has implications for the development of more effective antimicrobial therapies. Standard MIC testing does not consider the influence of the host milieu, potentially hindering therapeutic intervention. Salmonella induce polymyxin resistance during infection at levels of drug that far exceed dosages determined by MIC testing. Polymyxin treatment failed to control Salmonella infection and promotes the emergence of drug-resistant mutants.
Physicians rely on laboratory antimicrobial susceptibility testing of clinical isolates to identify a suitable antibiotic for therapy. Although the recommended antibiotics clear most bacterial infections, some patients fail to respond and require prolonged therapy, higher dosing or different antibiotics. Why does this occur and what are the possible implications? By studying antibiotic resistance in the context of infection, we identified a host-dependent mechanism that promotes antibiotic resistance at concentrations of drug that far exceed dosages determined by standardized antimicrobial testing. These findings question current antibiotic testing methods that have guided physician treatment practices and drug development for the last several decades.
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Affiliation(s)
| | - Douglas M Heithoff
- Dept. of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA ; Center for Nanomedicine, University of California, Santa Barbara, CA 93106, USA
| | - Selvi C Ersoy
- Dept. of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | - William R Shimp
- Dept. of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | - John K House
- University of Sydney, Faculty of Veterinary Science, Camden, NSW, Australia
| | - Jamey D Marth
- Dept. of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA ; Center for Nanomedicine, University of California, Santa Barbara, CA 93106, USA ; Sanford-Burnham Medical Research Institute, Cancer Research Center, La Jolla, CA 92037, USA
| | - Jeffrey W Smith
- Sanford-Burnham Medical Research Institute, Cancer Research Center, La Jolla, CA 92037, USA
| | - Michael J Mahan
- Dept. of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA ; Center for Nanomedicine, University of California, Santa Barbara, CA 93106, USA
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