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Zheng J, Liu X, Xiong Y, Meng Q, Li P, Zhang F, Liu X, Lin Z, Deng Q, Wen Z, Yu Z. AMXT-1501 targets membrane phospholipids against Gram-positive and -negative multidrug-resistant bacteria. Emerg Microbes Infect 2024; 13:2321981. [PMID: 38422452 PMCID: PMC10906134 DOI: 10.1080/22221751.2024.2321981] [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: 11/02/2023] [Accepted: 02/16/2024] [Indexed: 03/02/2024]
Abstract
The rapid proliferation of multidrug-resistant (MDR) bacterial pathogens poses a serious threat to healthcare worldwide. Carbapenem-resistant (CR) Enterobacteriaceae, which have near-universal resistance to available antimicrobials, represent a particularly concerning issue. Herein, we report the identification of AMXT-1501, a polyamine transport system inhibitor with antibacterial activity against Gram-positive and -negative MDR bacteria. We observed minimum inhibitory concentration (MIC)50/MIC90 values for AMXT-1501 in the range of 3.13-12.5 μM (2.24-8.93 μg /mL), including for methicillin-resistant Staphylococcus aureus (MRSA), CR Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. AMXT-1501 was more effective against MRSA and CR E. coli than vancomycin and tigecycline, respectively. Subinhibitory concentrations of AMXT-1501 reduced the biofilm formation of S. aureus and Enterococcus faecalis. Mechanistically, AMXT-1501 exposure damaged microbial membranes and increased membrane permeability and membrane potential by binding to cardiolipin (CL) and phosphatidylglycerol (PG). Importantly, AMXT-1501 pressure did not induce resistance readily in the tested pathogens.
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Affiliation(s)
- Jinxin Zheng
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infection, Shenzhen Nanshan People’s Hospital and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, People’s Republic of China
| | - Xiaoju Liu
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infection, Shenzhen Nanshan People’s Hospital and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, People’s Republic of China
| | - Yanpeng Xiong
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infection, Shenzhen Nanshan People’s Hospital and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, People’s Republic of China
| | - Qingyin Meng
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infection, Shenzhen Nanshan People’s Hospital and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, People’s Republic of China
| | - Peiyu Li
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infection, Shenzhen Nanshan People’s Hospital and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, People’s Republic of China
| | - Fan Zhang
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infection, Shenzhen Nanshan People’s Hospital and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, People’s Republic of China
- Department of Tuberculosis, Shenzhen Nanshan Center for Chronic Disease Control, Shenzhen, People’s Republic of China
| | - Xiaoming Liu
- Department of Gastroenterology, Shenzhen Qianhai Shekou Free Trade Zone Hospital, Shenzhen, People’s Republic of China
| | - Zhiwei Lin
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infection, Shenzhen Nanshan People’s Hospital and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, People’s Republic of China
| | - Qiwen Deng
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infection, Shenzhen Nanshan People’s Hospital and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, People’s Republic of China
| | - Zewen Wen
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infection, Shenzhen Nanshan People’s Hospital and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, People’s Republic of China
| | - Zhijian Yu
- Department of Infectious Diseases and Shenzhen Key Lab of Endogenous Infection, Shenzhen Nanshan People’s Hospital and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, People’s Republic of China
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Salinas-Restrepo C, Naranjo-Duran AM, Quintana J, Bueno J, Guzman F, Hoyos Palacio LM, Segura C. Short Antimicrobial Peptide Derived from the Venom Gland Transcriptome of Pamphobeteus verdolaga Increases Gentamicin Susceptibility of Multidrug-Resistant Klebsiella pneumoniae. Antibiotics (Basel) 2023; 13:6. [PMID: 38275316 PMCID: PMC10812672 DOI: 10.3390/antibiotics13010006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 11/07/2023] [Accepted: 11/17/2023] [Indexed: 01/27/2024] Open
Abstract
Infectious diseases account for nine percent of annual human deaths, and the widespread emergence of antimicrobial resistances threatens to significantly increase this number in the coming decades. The prospect of antimicrobial peptides (AMPs) derived from venomous animals presents an interesting alternative for developing novel active pharmaceutical ingredients (APIs). Small, cationic and amphiphilic peptides were predicted from the venom gland transcriptome of Pamphobeteus verdolaga using a custom database of the arthropod's AMPs. Ninety-four candidates were chemically synthesized and screened against ATCC® strains of Escherichia coli and Staphylococcus aureus. Among them, one AMP, named PvAMP66, showed broad-spectrum antimicrobial properties with selectivity towards Gram-negative bacteria. It also exhibited activity against Pseudomonas aeruginosa, as well as both an ATCC® and a clinically isolated multidrug-resistant (MDR) strain of K. pneumoniae. The scanning electron microscopy analysis revealed that PvAMP66 induced morphological changes of the MDR K. pneumoniae strain suggesting a potential "carpet model" mechanism of action. The isobologram analysis showed an additive interaction between PvAMP66 and gentamicin in inhibiting the growth of MDR K. pneumoniae, leading to a ten-fold reduction in gentamicin's effective concentration. A cytotoxicity against erythrocytes or peripheral blood mononuclear cells was observed at concentrations three to thirteen-fold higher than those exhibited against the evaluated bacterial strains. This evidence suggests that PvAMP66 can serve as a template for the development of AMPs with enhanced activity and deserves further pre-clinical studies as an API in combination therapy.
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Affiliation(s)
- Cristian Salinas-Restrepo
- Grupo Toxinología, Alternativas Terapéuticas y Alimentarias, Facultad de Ciencias Farmacéuticas y Alimentarias, Universidad de Antioquia, Medellín 050012, Colombia; (C.S.-R.); (A.M.N.-D.)
| | - Ana María Naranjo-Duran
- Grupo Toxinología, Alternativas Terapéuticas y Alimentarias, Facultad de Ciencias Farmacéuticas y Alimentarias, Universidad de Antioquia, Medellín 050012, Colombia; (C.S.-R.); (A.M.N.-D.)
| | - Juan Quintana
- Facultad de Medicina, Universidad Cooperativa de Colombia, Medellín 050012, Colombia;
| | - Julio Bueno
- Grupo Reproducción, Facultad de Medicina, Universidad de Antioquia, Medellín 050012, Colombia;
| | - Fanny Guzman
- Núcleo Biotecnología Curauma (NBC), Pontificia Universidad Católica de Valparaíso, Valparaíso 3100000, Chile;
| | - Lina M. Hoyos Palacio
- Escuela de Ciencias de la Salud, Grupo de Investigación Biología de Sistemas, Universidad Pontificia Bolivariana, Medellín 050031, Colombia;
| | - Cesar Segura
- Grupo Malaria, Facultad de Medicina, Universidad de Antioquia, Medellín 050012, Colombia
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Dennison SR, Morton LH, Badiani K, Harris F, Phoenix DA. Bacterial susceptibility and resistance to modelin-5. SOFT MATTER 2023; 19:8247-8263. [PMID: 37869970 DOI: 10.1039/d3sm01007d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2023]
Abstract
Modelin-5 (M5-NH2) killed Pseudomonas aeruginosa with a minimum lethal concentration (MLC) of 5.86 μM and strongly bound its cytoplasmic membrane (CM) with a Kd of 23.5 μM. The peptide adopted high levels of amphiphilic α-helical structure (75.0%) and penetrated the CM hydrophobic core (8.0 mN m-1). This insertion destabilised CM structure via increased lipid packing and decreased fluidity (ΔGmix < 0), which promoted high levels of lysis (84.1%) and P. aeruginosa cell death. M5-NH2 showed a very strong affinity (Kd = 3.5 μM) and very high levels of amphiphilic α-helical structure with cardiolipin membranes (96.0%,) which primarily drove the peptide's membranolytic action against P. aeruginosa. In contrast, M5-NH2 killed Staphylococcus aureus with an MLC of 147.6 μM and weakly bound its CM with a Kd of 117.6 μM, The peptide adopted low levels of amphiphilic α-helical structure (35.0%) and only penetrated the upper regions of the CM (3.3 mN m-1). This insertion stabilised CM structure via decreased lipid packing and increased fluidity (ΔGmix > 0) and promoted only low levels of lysis (24.3%). The insertion and lysis of the S. aureus CM by M5-NH2 showed a strong negative correlation with its lysyl phosphatidylglycerol (Lys-PG) content (R2 > 0.98). In combination, these data suggested that Lys-PG mediated mechanisms inhibited the membranolytic action of M5-NH2 against S. aureus, thereby rendering the organism resistant to the peptide. These results are discussed in relation to structure/function relationships of M5-NH2 and CM lipids that underpin bacterial susceptibility and resistance to the peptide.
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Affiliation(s)
- Sarah R Dennison
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston PR1 2HE, UK.
| | - Leslie Hg Morton
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston PR1 2HE, UK.
| | - Kamal Badiani
- Pepceuticals Limited, 4 Feldspar Close, Warrens Park, Enderby, Leicestershire, LE19 4JS, UK
| | - Frederick Harris
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston PR1 2HE, UK.
| | - David A Phoenix
- Office of the Vice Chancellor, London South Bank University, 103 Borough Road, London SE1 0AA, UK
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Kozon-Markiewicz D, Kopiasz RJ, Głusiec M, Łukasiak A, Bednarczyk P, Jańczewski D. Membrane lytic activity of antibacterial ionenes, critical role of phosphatidylcholine (PC) and cardiolipin (CL). Colloids Surf B Biointerfaces 2023; 229:113480. [PMID: 37536168 DOI: 10.1016/j.colsurfb.2023.113480] [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: 05/25/2023] [Revised: 07/16/2023] [Accepted: 07/26/2023] [Indexed: 08/05/2023]
Abstract
Understanding the mechanism by which an antibacterial agent interacts with a model membrane provides vital information for better design of future antibiotics. In this study, we investigated two antibacterial polymers, hydrophilic C0-T-p and hydrophobic C8-T-p ionenes, known for their potent antimicrobial activity and ability to disrupt the integrity of lipid bilayers. Our hypothesize is that the composition of a lipid bilayer alters the mechanism of ionenes action, potentially providing an explanation for the observed differences in their bioactivity and selectivity. Calcein release experiments utilizing a range of liposomes to examine the impact of (i) cardiolipin (CL) to phosphatidylglycerol (PG) ratio, (ii) overall vesicle charge, and (iii) phosphatidylethanolamine (PE) to phosphatidylcholine (PC) ratio on the activity of ionenes were performed. Additionally, polymer-bilayer interactions were also investigated through vesicle fusion assay and the black lipid membrane (BLM) technique The activity of C0-T-p is strongly influenced by the amount of cardiolipin, while the activity of C8-T-p primarily depends on the overall vesicle charge. Consequently, C0-T-p acts through interactions with CL, whereas C8-T-p modifies the bulk properties of the membrane in a less-specific manner. Moreover, the presence of a small amount of PC in the membrane makes the vesicle resistant to permeabilization by tested molecules. Intriguingly, more hydrophilic C0-T-p retains higher membrane activity compared to the hydrophobic C8-T-p. However, both ionenes induce vesicle fusion and increase lipid bilayer ion permeability.
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Affiliation(s)
| | - Rafał J Kopiasz
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Martyna Głusiec
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Agnieszka Łukasiak
- Department of Physics and Biophysics, Institute of Biology, Warsaw University of Life Sciences - SGGW, Warsaw, Poland
| | - Piotr Bednarczyk
- Department of Physics and Biophysics, Institute of Biology, Warsaw University of Life Sciences - SGGW, Warsaw, Poland
| | - Dominik Jańczewski
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
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5
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Kadeřábková N, Mahmood AJS, Furniss RCD, Mavridou DAI. Making a chink in their armor: Current and next-generation antimicrobial strategies against the bacterial cell envelope. Adv Microb Physiol 2023; 83:221-307. [PMID: 37507160 PMCID: PMC10517717 DOI: 10.1016/bs.ampbs.2023.05.003] [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] [Indexed: 07/30/2023]
Abstract
Gram-negative bacteria are uniquely equipped to defeat antibiotics. Their outermost layer, the cell envelope, is a natural permeability barrier that contains an array of resistance proteins capable of neutralizing most existing antimicrobials. As a result, its presence creates a major obstacle for the treatment of resistant infections and for the development of new antibiotics. Despite this seemingly impenetrable armor, in-depth understanding of the cell envelope, including structural, functional and systems biology insights, has promoted efforts to target it that can ultimately lead to the generation of new antibacterial therapies. In this article, we broadly overview the biology of the cell envelope and highlight attempts and successes in generating inhibitors that impair its function or biogenesis. We argue that the very structure that has hampered antibiotic discovery for decades has untapped potential for the design of novel next-generation therapeutics against bacterial pathogens.
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Affiliation(s)
- Nikol Kadeřábková
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States
| | - Ayesha J S Mahmood
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States
| | - R Christopher D Furniss
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Despoina A I Mavridou
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States; John Ring LaMontagne Center for Infectious Diseases, The University of Texas at Austin, Austin, TX, United States.
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Panda G, Dash S, Sahu SK. Harnessing the Role of Bacterial Plasma Membrane Modifications for the Development of Sustainable Membranotropic Phytotherapeutics. MEMBRANES 2022; 12:914. [PMID: 36295673 PMCID: PMC9612325 DOI: 10.3390/membranes12100914] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 09/08/2022] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
Membrane-targeted molecules such as cationic antimicrobial peptides (CAMPs) are amongst the most advanced group of antibiotics used against drug-resistant bacteria due to their conserved and accessible targets. However, multi-drug-resistant bacteria alter their plasma membrane (PM) lipids, such as lipopolysaccharides (LPS) and phospholipids (PLs), to evade membrane-targeted antibiotics. Investigations reveal that in addition to LPS, the varying composition and spatiotemporal organization of PLs in the bacterial PM are currently being explored as novel drug targets. Additionally, PM proteins such as Mla complex, MPRF, Lpts, lipid II flippase, PL synthases, and PL flippases that maintain PM integrity are the most sought-after targets for development of new-generation drugs. However, most of their structural details and mechanism of action remains elusive. Exploration of the role of bacterial membrane lipidome and proteome in addition to their organization is the key to developing novel membrane-targeted antibiotics. In addition, membranotropic phytochemicals and their synthetic derivatives have gained attractiveness as popular herbal alternatives against bacterial multi-drug resistance. This review provides the current understanding on the role of bacterial PM components on multidrug resistance and their targeting with membranotropic phytochemicals.
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Affiliation(s)
- Gayatree Panda
- Department of Biotechnology, Maharaja Sriram Chandra Bhanjadeo University (Erstwhile: North Orissa University), Baripada 757003, India
| | - Sabyasachi Dash
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY 10065, USA
| | - Santosh Kumar Sahu
- Department of Biotechnology, Maharaja Sriram Chandra Bhanjadeo University (Erstwhile: North Orissa University), Baripada 757003, India
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Ouellette SP, Fisher-Marvin LA, Harpring M, Lee J, Rucks EA, Cox JV. Localized cardiolipin synthesis is required for the assembly of MreB during the polarized cell division of Chlamydia trachomatis. PLoS Pathog 2022; 18:e1010836. [PMID: 36095021 PMCID: PMC9499288 DOI: 10.1371/journal.ppat.1010836] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 09/22/2022] [Accepted: 08/29/2022] [Indexed: 11/18/2022] Open
Abstract
Pathogenic Chlamydia species are coccoid bacteria that use the rod-shape determining protein MreB to direct septal peptidoglycan synthesis during their polarized cell division process. How the site of polarized budding is determined in this bacterium, where contextual features like membrane curvature are seemingly identical, is unclear. We hypothesized that the accumulation of the phospholipid, cardiolipin (CL), in specific regions of the cell membrane induces localized membrane changes that trigger the recruitment of MreB to the site where the bud will arise. To test this, we ectopically expressed cardiolipin synthase (Cls) and observed a polar distribution for this enzyme in Chlamydia trachomatis. In early division intermediates, Cls was restricted to the bud site where MreB is localized and peptidoglycan synthesis is initiated. The localization profile of 6xHis tagged Cls (Cls_6xH) throughout division mimicked the distribution of lipids that stain with NAO, a dye that labels CL. Treatment of Chlamydia with 3’,6-dinonylneamine (diNN), an antibiotic targeting CL-containing membrane domains, resulted in redistribution of Cls_6xH and NAO-staining phospholipids. In addition, 6xHis tagged MreB localization was altered by diNN treatment, suggesting an upstream regulatory role for CL-containing membranes in directing the assembly of MreB. This hypothesis is consistent with the observation that the clustered localization of Cls_6xH is not dependent upon MreB function or peptidoglycan synthesis. Furthermore, expression of a CL-binding protein at the inner membrane of C. trachomatis dramatically inhibited bacterial growth supporting the importance of CL in the division process. Our findings implicate a critical role for localized CL synthesis in driving MreB assembly at the bud site during the polarized cell division of Chlamydia.
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Affiliation(s)
- Scot P. Ouellette
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Nebraska Medical Center, Omaha, Nebraska
- * E-mail: (SPO); (JVC)
| | - Laura A. Fisher-Marvin
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Nebraska Medical Center, Omaha, Nebraska
| | - McKenna Harpring
- Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Junghoon Lee
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Nebraska Medical Center, Omaha, Nebraska
| | - Elizabeth A. Rucks
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Nebraska Medical Center, Omaha, Nebraska
| | - John V. Cox
- Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee
- * E-mail: (SPO); (JVC)
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8
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MacDermott-Opeskin HI, Panizza A, Eijkelkamp BA, O'Mara ML. Dynamics of the Acinetobacter baumannii inner membrane under exogenous polyunsaturated fatty acid stress. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183908. [PMID: 35276227 DOI: 10.1016/j.bbamem.2022.183908] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 02/11/2022] [Accepted: 03/05/2022] [Indexed: 01/04/2023]
Abstract
Exogenous polyunsaturated fatty acids (PUFAs) are readily incorporated into the synthesis pathways of A. baumannii membrane phospholipids, where they contribute to reduced bacterial fitness and increased antimicrobial susceptibility. Here we examine the impact of PUFA membrane modification on membrane organisation and biophysical properties using coarse grained MARTINI simulations of chemically representative membrane models developed from mass-spectrometry datasets of an untreated, arachidonic acid (AA) treated and docosahexaenoic acid (DHA) treated A. baumannii membranes. Enzymatic integration of AA or DHA into phospholipids of the A. baumannii membrane resulted in modulation of membrane biophysical properties. Membrane thickness decreased slightly following PUFA treatment, concomitant with changes in the lateral area per lipid of each lipid headgroup class. PUFA treatment resulted in a decrease in membrane ordering and an increase in lipid lateral diffusion. Changes in lateral membrane organisation were observed in the PUFA treated membranes, with a concurrent increase in ordered cardiolipin domains and disordered PUFA-containing domains. Notably, separation between ordered and disordered domains was enhanced and was more pronounced for DHA relative to AA, providing a possible mechanism for greater antimicrobial action of DHA relative to AA observed experimentally. Furthermore, the membrane active antimicrobial, pentamidine, preferentially adsorbs to cardiolipin domains of the A. baumannii model membranes. This interaction, and membrane penetration of pentamidine, was enhanced following PUFA treatment. Cumulatively, this work explores the wide-ranging effects of PUFA incorporation on the A. baumannii membrane and provides a molecular basis for bacterial inner membrane disruption by PUFAs.
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Affiliation(s)
- Hugo I MacDermott-Opeskin
- Research School of Chemistry, College of Science, Australian National University, Canberra, ACT, 2601, Australia
| | - Alessandra Panizza
- Research School of Chemistry, College of Science, Australian National University, Canberra, ACT, 2601, Australia
| | - Bart A Eijkelkamp
- Molecular Science and Technology, College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia
| | - Megan L O'Mara
- Research School of Chemistry, College of Science, Australian National University, Canberra, ACT, 2601, Australia.
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9
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MacDermott-Opeskin HI, Gupta V, O’Mara ML. Lipid-mediated antimicrobial resistance: a phantom menace or a new hope? Biophys Rev 2022; 14:145-162. [PMID: 35251360 PMCID: PMC8880301 DOI: 10.1007/s12551-021-00912-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 11/14/2021] [Indexed: 02/06/2023] Open
Abstract
Abstract The proposition of a post-antimicrobial era is all the more realistic with the continued rise of antimicrobial resistance. The development of new antimicrobials is failing to counter the ever-increasing rates of bacterial antimicrobial resistance. This necessitates novel antimicrobials and drug targets. The bacterial cell membrane is an essential and highly conserved cellular component in bacteria and acts as the primary barrier for entry of antimicrobials into the cell. Although previously under-exploited as an antimicrobial target, the bacterial cell membrane is attractive for the development of novel antimicrobials due to its importance in pathogen viability. Bacterial cell membranes are diverse assemblies of macromolecules built around a central lipid bilayer core. This lipid bilayer governs the overall membrane biophysical properties and function of its membrane-embedded proteins. This mini-review will outline the mechanisms by which the bacterial membrane causes and controls resistance, with a focus on alterations in the membrane lipid composition, chemical modification of constituent lipids, and the efflux of antimicrobials by membrane-embedded efflux systems. Thorough insight into the interplay between membrane-active antimicrobials and lipid-mediated resistance is needed to enable the rational development of new antimicrobials. In particular, the union of computational approaches and experimental techniques for the development of innovative and efficacious membrane-active antimicrobials is explored.
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Affiliation(s)
- Hugo I. MacDermott-Opeskin
- Research School of Chemistry, College of Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Vrinda Gupta
- Research School of Chemistry, College of Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Megan L. O’Mara
- Research School of Chemistry, College of Science, The Australian National University, Canberra, ACT 2601 Australia
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10
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Influence of lipid bilayer composition on the activity of antimicrobial quaternary ammonium ionenes, the interplay of intrinsic lipid curvature and polymer hydrophobicity, the role of cardiolipin. Colloids Surf B Biointerfaces 2021; 207:112016. [PMID: 34364250 DOI: 10.1016/j.colsurfb.2021.112016] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 07/20/2021] [Accepted: 07/26/2021] [Indexed: 01/03/2023]
Abstract
Incorporation of hydrophobic component into amphiphilic polycations structure is frequently accompanied by an increase of antimicrobial activity. There is, however, a group of relatively hydrophilic polycations containing quaternary ammonium moieties along mainchain, ionenes, which also display strong antimicrobial and limited hemolytic properties. In this work, an influence of a hydrophobic side group length on antimicrobial mechanism of action is investigated in a series of novel amphiphilic ionenes. High antimicrobial activity was found by determination of minimum inhibitory concentration (MIC) and minimum bactericidal, and fungicidal concentration (MBC and MFC) in both growth media and a buffer. Biocompatibility was estimated by hemolytic and mammalian cells viability assays. Mechanistic studies were performed using large unilamellar vesicles (LUVs) with different lipid composition, as simplified models of cell membranes. The investigated ionenes are potent and selective antimicrobial molecules displaying a decrease of antimicrobial activity correlated with increase of hydrophobicity. Studies using LUVs revealed that the cardiolipin is an essential component responsible for the lipid bilayer permeabilization by investigated ionens. In contrast to relatively hydrophilic ionenes, more hydrophobic polymers showed an ability to stabilize membranes composed of lipids with negative spontaneous curvature in a certain range of polymer to lipid ratio. The results substantially contribute to the understanding of antimicrobial activity of the investigated class of polymers.
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11
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Luchini A, Cavasso D, Radulescu A, D'Errico G, Paduano L, Vitiello G. Structural Organization of Cardiolipin-Containing Vesicles as Models of the Bacterial Cytoplasmic Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:8508-8516. [PMID: 34213914 DOI: 10.1021/acs.langmuir.1c00981] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The bacterial cytoplasmic membrane is the innermost bacterial membrane and is mainly composed of three different phospholipid species, i.e., phosphoethanolamine (PE), phosphoglycerol (PG), and cardiolipin (CL). In particular, PG and CL are responsible for the negative charge of the membrane and are often the targets of cationic antimicrobial agents. The growing resistance of bacteria toward the available antibiotics requires the development of new and more efficient antibacterial drugs. In this context, studying the physicochemical properties of the bacterial cytoplasmic membrane is pivotal for understanding drug-membrane interactions at the molecular level as well as for designing drug-testing platforms. Here, we discuss the preparation and characterization of PE/PG/CL vesicle suspensions, which contain all of the main lipid components of the bacterial cytoplasmic membrane. The vesicle suspensions were characterized by means of small-angle neutron scattering, dynamic light scattering, and electron paramagnetic spectroscopy. By combining solution scattering and spectroscopy techniques, we propose a detailed description of the impact of different CL concentrations on the structure and dynamics of the PE/PG bilayer. CL induces the formation of thicker bilayers, which exhibit higher curvature and are overall more fluid. The experimental results contribute to shed light on the structure and dynamics of relevant model systems of the bacterial cytoplasmic membrane.
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Affiliation(s)
- Alessandra Luchini
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Domenico Cavasso
- Department of Chemical Science, University of Naples Federico II, Complesso di Monte Sant'Angelo, Via Cinthia 4, 80126 Naples, Italy
| | - Aurel Radulescu
- Jülich Centre for Neutron Science, Garching Forschungszentrum, Lichtenbergstrasse 1, D-85747 Garching bei München, Germany
| | - Gerardino D'Errico
- Department of Chemical Science, University of Naples Federico II, Complesso di Monte Sant'Angelo, Via Cinthia 4, 80126 Naples, Italy
- CSGI, Center for Colloid and Surface Science, Via della Lastruccia 3, 50019 Sesto Fiorentino FI, Italy
| | - Luigi Paduano
- Department of Chemical Science, University of Naples Federico II, Complesso di Monte Sant'Angelo, Via Cinthia 4, 80126 Naples, Italy
- CSGI, Center for Colloid and Surface Science, Via della Lastruccia 3, 50019 Sesto Fiorentino FI, Italy
| | - Giuseppe Vitiello
- CSGI, Center for Colloid and Surface Science, Via della Lastruccia 3, 50019 Sesto Fiorentino FI, Italy
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, Piazzale Tecchio 80, 80125 Naples, Italy
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12
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Marx L, Semeraro EF, Mandl J, Kremser J, Frewein MP, Malanovic N, Lohner K, Pabst G. Bridging the Antimicrobial Activity of Two Lactoferricin Derivatives in E. coli and Lipid-Only Membranes. FRONTIERS IN MEDICAL TECHNOLOGY 2021; 3:625975. [PMID: 35047906 PMCID: PMC8757871 DOI: 10.3389/fmedt.2021.625975] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 01/19/2021] [Indexed: 11/13/2022] Open
Abstract
We coupled the antimicrobial activity of two well-studied lactoferricin derivatives, LF11-215 and LF11-324, in Escherichia coli and different lipid-only mimics of its cytoplasmic membrane using a common thermodynamic framework for peptide partitioning. In particular, we combined an improved analysis of microdilution assays with ζ-potential measurements, which allowed us to discriminate between the maximum number of surface-adsorbed peptides and peptides fully partitioned into the bacteria. At the same time, we measured the partitioning of the peptides into vesicles composed of phosphatidylethanolamine (PE), phosphatidylgylcerol (PG), and cardiolipin (CL) mixtures using tryptophan fluorescence and determined their membrane activity using a dye leakage assay and small-angle X-ray scattering. We found that the vast majority of LF11-215 and LF11-324 readily enter inner bacterial compartments, whereas only 1-5% remain surface bound. We observed comparable membrane binding of both peptides in membrane mimics containing PE and different molar ratios of PG and CL. The peptides' activity caused a concentration-dependent dye leakage in all studied membrane mimics; however, it also led to the formation of large aggregates, part of which contained collapsed multibilayers with sandwiched peptides in the interstitial space between membranes. This effect was least pronounced in pure PG vesicles, requiring also the highest peptide concentration to induce membrane permeabilization. In PE-containing systems, we additionally observed an effective shielding of the fluorescent dyes from leakage even at highest peptide concentrations, suggesting a coupling of the peptide activity to vesicle fusion, being mediated by the intrinsic lipid curvatures of PE and CL. Our results thus show that LF11-215 and LF11-324 effectively target inner bacterial components, while the stored elastic stress makes membranes more vulnerable to peptide translocation.
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Affiliation(s)
- Lisa Marx
- Department of Biophysics, Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
| | - Enrico F. Semeraro
- Department of Biophysics, Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
| | - Johannes Mandl
- Department of Biophysics, Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
| | - Johannes Kremser
- Department of Biophysics, Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
| | - Moritz P. Frewein
- Department of Biophysics, Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
- Soft Matter Science and Support Group, Institut Laue-Langevin, Grenoble, France
| | - Nermina Malanovic
- Department of Biophysics, Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
| | - Karl Lohner
- Department of Biophysics, Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
| | - Georg Pabst
- Department of Biophysics, Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
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13
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Yang H, Jackson SN, Woods AS, Goodlett DR, Ernst RK, Scott AJ. Streamlined Analysis of Cardiolipins in Prokaryotic and Eukaryotic Samples Using a Norharmane Matrix by MALDI-MSI. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:2495-2502. [PMID: 32924474 PMCID: PMC8681877 DOI: 10.1021/jasms.0c00201] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Cardiolipins (CLs) are an important, regulated lipid class both in prokaryotic and eukaryotic cells, yet they remain largely unexplored by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) in tissues. To date, no in-depth optimization studies of label-free visualization of CLs in complex biological samples have been reported. Here we report a streamlined modification to our previously reported MALDI-MSI method for detection of endogenous CLs in prokaryotic and eukaryotic cells based on preparation with norharmane (NRM) matrix. Notably, the use of NRM matrix permitted sensitive detection (4.7 pg/mm2) of spotted CL synthetic standards. By contrast, four other MALDI matrices commonly used for lipid analysis failed to generate CL ions. Using this NRM-based method, endogenous CLs were detected from two types of complex biological samples: dried bacterial arrays and mouse tissue sections. In both cases, using NRM resulted in a better signal/noise for CL ions than the other matrices. Furthermore, inclusion of a washing step improved CL detection from tissue and this combined tissue preparation method (washing and NRM matrix) was used to profile normal mouse lung. Mouse lung yielded 26 unique CLs that were mapped and identified. Consistent with previous findings, CLs containing polyunsaturated fatty acids (PUFAs) were found in abundance in the airway and vascular features of the lung. This work represents a comprehensive investigation of detection conditions for CL using MALDI-MSI in complex biological samples that resulted in a streamlined method that enables future studies of the biological role(s) of CL in tissue.
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Affiliation(s)
- Hyojik Yang
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore 21201, MD, USA
| | | | - Amina S. Woods
- Structural Biology Core, NIDA IRP, NIH, Baltimore 21224, MD, USA
- Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore 21205, MD, USA
| | - David R. Goodlett
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore 21201, MD, USA
- International Centre for Cancer Vaccine Science, University of Gdansk, Gdansk, 80-308, Poland, EU
| | - Robert K. Ernst
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore 21201, MD, USA
| | - Alison J. Scott
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore 21201, MD, USA
- Maastricht MultiModal Molecular Imaging (M4I) Institute, Maastricht University, Maastricht 6229 ER, Netherlands, EU
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14
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Dezanet C, Kempf J, Mingeot-Leclercq MP, Décout JL. Amphiphilic Aminoglycosides as Medicinal Agents. Int J Mol Sci 2020; 21:E7411. [PMID: 33049963 PMCID: PMC7583001 DOI: 10.3390/ijms21197411] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 09/27/2020] [Accepted: 10/02/2020] [Indexed: 12/25/2022] Open
Abstract
The conjugation of hydrophobic group(s) to the polycationic hydrophilic core of the antibiotic drugs aminoglycosides (AGs), targeting ribosomal RNA, has led to the development of amphiphilic aminoglycosides (AAGs). These drugs exhibit numerous biological effects, including good antibacterial effects against susceptible and multidrug-resistant bacteria due to the targeting of bacterial membranes. In the first part of this review, we summarize our work in identifying and developing broad-spectrum antibacterial AAGs that constitute a new class of antibiotic agents acting on bacterial membranes. The target-shift strongly improves antibiotic activity against bacterial strains that are resistant to the parent AG drugs and to antibiotic drugs of other classes, and renders the emergence of resistant Pseudomonas aeruginosa strains highly difficult. Structure-activity and structure-eukaryotic cytotoxicity relationships, specificity and barriers that need to be crossed in their development as antibacterial agents are delineated, with a focus on their targets in membranes, lipopolysaccharides (LPS) and cardiolipin (CL), and the corresponding mode of action against Gram-negative bacteria. At the end of the first part, we summarize the other recent advances in the field of antibacterial AAGs, mainly published since 2016, with an emphasis on the emerging AAGs which are made of an AG core conjugated to an adjuvant or an antibiotic drug of another class (antibiotic hybrids). In the second part, we briefly illustrate other biological and biochemical effects of AAGs, i.e., their antifungal activity, their use as delivery vehicles of nucleic acids, of short peptide (polyamide) nucleic acids (PNAs) and of drugs, as well as their ability to cleave DNA at abasic sites and to inhibit the functioning of connexin hemichannels. Finally, we discuss some aspects of structure-activity relationships in order to explain and improve the target selectivity of AAGs.
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Affiliation(s)
- Clément Dezanet
- Molecular Pharmacochemistry Department, University Grenoble Alpes, CNRS, 470 Rue de la Chimie, F-38000 Grenoble, France; (C.D.); (J.K.)
| | - Julie Kempf
- Molecular Pharmacochemistry Department, University Grenoble Alpes, CNRS, 470 Rue de la Chimie, F-38000 Grenoble, France; (C.D.); (J.K.)
| | - Marie-Paule Mingeot-Leclercq
- Cellular and Molecular Pharmacology Unit, Louvain Drug Research Institute, Catholic University of Louvain, Avenue E. Mounier 73, UCL B1.73.05, 1200 Brussels, Belgium
| | - Jean-Luc Décout
- Molecular Pharmacochemistry Department, University Grenoble Alpes, CNRS, 470 Rue de la Chimie, F-38000 Grenoble, France; (C.D.); (J.K.)
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15
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Pinkas D, Fišer R, Kozlík P, Dolejšová T, Hryzáková K, Konopásek I, Mikušová G. Bacillus subtilis cardiolipin protects its own membrane against surfactin-induced permeabilization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183405. [DOI: 10.1016/j.bbamem.2020.183405] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 05/15/2020] [Accepted: 06/19/2020] [Indexed: 11/16/2022]
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16
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Laut CL, Perry WJ, Metzger AL, Weiss A, Stauff DL, Walker S, Caprioli RM, Skaar EP. Bacillus anthracis Responds to Targocil-Induced Envelope Damage through EdsRS Activation of Cardiolipin Synthesis. mBio 2020; 11:e03375-19. [PMID: 32234818 PMCID: PMC7157781 DOI: 10.1128/mbio.03375-19] [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: 12/23/2019] [Accepted: 02/27/2020] [Indexed: 01/08/2023] Open
Abstract
Bacillus anthracis is a spore-forming bacterium that causes devastating infections and has been used as a bioterror agent. This pathogen can survive hostile environments through the signaling activity of two-component systems, which couple environmental sensing with transcriptional activation to initiate a coordinated response to stress. In this work, we describe the identification of a two-component system, EdsRS, which mediates the B. anthracis response to the antimicrobial compound targocil. Targocil is a cell envelope-targeting compound that is toxic to B. anthracis at high concentrations. Exposure to targocil causes damage to the cellular barrier and activates EdsRS to induce expression of a previously uncharacterized cardiolipin synthase, which we have named ClsT. Both EdsRS and ClsT are required for protection against targocil-dependent damage. Induction of clsT by EdsRS during targocil treatment results in an increase in cardiolipin levels, which protects B. anthracis from envelope damage. Together, these results reveal that a two-component system signaling response to an envelope-targeting antimicrobial induces production of a phospholipid associated with stabilization of the membrane. Cardiolipin is then used to repair envelope damage and promote B. anthracis viability.IMPORTANCE Compromising the integrity of the bacterial cell barrier is a common action of antimicrobials. Targocil is an antimicrobial that is active against the bacterial envelope. We hypothesized that Bacillus anthracis, a potential weapon of bioterror, senses and responds to targocil to alleviate targocil-dependent cell damage. Here, we show that targocil treatment increases the permeability of the cellular envelope and is particularly toxic to B. anthracis spores during outgrowth. In vegetative cells, two-component system signaling through EdsRS is activated by targocil. This results in an increase in the production of cardiolipin via a cardiolipin synthase, ClsT, which restores the loss of barrier function, thereby reducing the effectiveness of targocil. By elucidating the B. anthracis response to targocil, we have uncovered an intrinsic mechanism that this pathogen employs to resist toxicity and have revealed therapeutic targets that are important for bacterial defense against structural damage.
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Affiliation(s)
- Clare L Laut
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - William J Perry
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee, USA
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | | | - Andy Weiss
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Devin L Stauff
- Department of Biology, Grove City College, Grove City, Pennsylvania, USA
| | - Suzanne Walker
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Richard M Caprioli
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee, USA
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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17
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Sahu AK, Mishra J, Mishra AK. Introducing Tween-curcumin niosomes: preparation, characterization and microenvironment study. SOFT MATTER 2020; 16:1779-1791. [PMID: 31970372 DOI: 10.1039/c9sm02416f] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
In this work, we report unusual niosomes (non-ionic surfactant based vesicles), prepared using non-ionic surfactant Tween 80 (T80) as well as Tween 20 (T20) and curcumin. Conventional niosomes consist of non-ionic surfactant and cholesterol. We found that, despite being a probiotic, curcumin plays a similar role to cholesterol in the formation and stabilization of niosomes. The prepared Tween-curcumin niosomes were characterised using Dynamic Light Scattering (DLS), zeta potential, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and Transmission Electron Microscopy (TEM) techniques. The curcumin-induced micelle to vesicle transition in the Tween surfactants was investigated by DLS, zeta potential, fluorescence anisotropy, and fluorescence lifetime studies. At room temperature (298 K), the prepared niosomes were found to be stable; however, at a higher temperature (333 K), the niosomes degrade gradually and irreversibly to form micelles. The temperature-dependent vesicle to micelle degradation was monitored using fluorescence anisotropy, absorption, DLS and Differential Scanning Calorimetry (DSC) measurements. Further, the Tween-curcumin niosomes show a controlled release of curcumin, which could open up the possibility of multidrug therapy.
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Affiliation(s)
- Anand Kumar Sahu
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India.
| | - Jhili Mishra
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India.
| | - Ashok Kumar Mishra
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India.
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18
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Malik E, Phoenix DA, Badiani K, Snape TJ, Harris F, Singh J, Morton LHG, Dennison SR. Biophysical studies on the antimicrobial activity of linearized esculentin 2EM. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183141. [PMID: 31790693 DOI: 10.1016/j.bbamem.2019.183141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 10/25/2019] [Accepted: 11/27/2019] [Indexed: 02/07/2023]
Abstract
Linearized esculentin 2 EM (E2EM-lin) from the frog, Glandirana emeljanovi was highly active against Gram-positive bacteria (minimum lethal concentration ≤ 5.0 μM) and strongly α-helical in the presence of lipid mimics of their membranes (>55.0%). The N-terminal α-helical structure adopted by E2EM-lin showed the potential to form a membrane interactive, tilted peptide with an hydrophobicity gradient over residues 9 to 23. E2EM-lin inserted strongly into lipid mimics of membranes from Gram-positive bacteria (maximal surface pressure changes ≥5.5 mN m-1), inducing increased rigidity (Cs-1 ↑), thermodynamic instability (ΔGmix < 0 → ΔGmix > 0) and high levels of lysis (>50.0%). These effects appeared to be driven by the high anionic lipid content of membranes from Gram-positive bacteria; namely phosphatidylglycerol (PG) and cardiolipin (CL) species. The high levels of α-helicity (60.0%), interaction (maximal surface pressure change = 6.7 mN m-1) and lysis (66.0%) shown by E2EM-lin with PG species was a major driver in the ability of the peptide to lyse and kill Gram-positive bacteria. E2EM-lin also showed high levels of α-helicity (62.0%) with CL species but only low levels of interaction (maximal surface pressure change = 2.9 mN m-1) and lysis (21.0%) with the lipid. These combined data suggest that E2EM-lin has a specificity for killing Gram-positive bacteria that involves the formation of tilted structure and appears to be primarily driven by PG-mediated membranolysis. These structure/function relationships are used to help explain the pore forming process proposed to describe the membranolytic, antibacterial action of E2EM-lin.
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Affiliation(s)
- Erum Malik
- School of Forensic and Applied Science, University of Central Lancashire, Preston PR1 2HE, UK
| | - David A Phoenix
- Office of the Vice Chancellor, London South Bank University, 103 Borough Road, London SE1 0AA, UK
| | - Kamal Badiani
- Pepceuticals Limited, 4 Feldspar Close, Warrens Park, Enderby, Leicestershire LE19 4JS, UK
| | - Timothy J Snape
- School of Pharmacy and Biological Sciences, University of Central Lancashire, Preston PR1 2HE, UK
| | - Frederick Harris
- School of Forensic and Applied Science, University of Central Lancashire, Preston PR1 2HE, UK
| | - Jaipaul Singh
- School of Forensic and Applied Science, University of Central Lancashire, Preston PR1 2HE, UK
| | - Leslie Hugh Glyn Morton
- School of Forensic and Applied Science, University of Central Lancashire, Preston PR1 2HE, UK
| | - Sarah R Dennison
- School of Pharmacy and Biological Sciences, University of Central Lancashire, Preston PR1 2HE, UK.
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19
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Casciaro B, Lin Q, Afonin S, Loffredo MR, de Turris V, Middel V, Ulrich AS, Di YP, Mangoni ML. Inhibition of Pseudomonas aeruginosa biofilm formation and expression of virulence genes by selective epimerization in the peptide Esculentin-1a(1-21)NH 2. FEBS J 2019; 286:3874-3891. [PMID: 31144441 DOI: 10.1111/febs.14940] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 03/22/2019] [Accepted: 05/28/2019] [Indexed: 12/21/2022]
Abstract
Pseudomonas aeruginosa is a pathogenic bacterium known to cause serious human infections, especially in immune-compromised patients. This is due to its unique ability to transform from a drug-tolerant planktonic to a more dangerous and treatment-resistant sessile life form, called biofilm. Recently, two derivatives of the frog skin antimicrobial peptide esculentin-1a, i.e. Esc(1-21) and its D-amino acids containing diastereomer Esc(1-21)-1c, were characterized for their powerful anti-Pseudomonal activity against both forms. Prevention of biofilm formation already in its early stages could be even more advantageous for counteracting infections induced by this bacterium. In this work, we studied how the diastereomer Esc(1-21)-1c can inhibit Pseudomonas biofilm formation in comparison to the parent peptide and two clinically-used conventional antibiotics, i.e. colistin and aztreonam, when applied at dosages below the minimal growth inhibitory concentration. Biofilm prevention was correlated to the peptides' ability to inhibit Pseudomonas motility and to reduce the production of virulent metabolites, for example, pyoverdine and rhamnolipids. Furthermore, the molecular mechanism underlying these activities was evaluated by studying the peptides' effect on the expression of key genes involved in the virulence and motility of bacteria, as well as by monitoring the peptides' binding to the bacterial signaling nucleotide ppGpp. Our results demonstrate that the presence of only two D-amino acids in Esc(1-21)-1c is sufficient to downregulate ppGpp-mediated expression of biofilm-associated genes, presumably as a result of higher peptide stability and therefore prolonged interaction with the nucleotide. Overall, these studies should assist efficient design and optimization of new anti-infective agents with multiple pharmacologically beneficial properties.
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Affiliation(s)
- Bruno Casciaro
- Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, Italy.,Center for Life Nano Science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Qiao Lin
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Sergii Afonin
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Maria Rosa Loffredo
- Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, Italy
| | - Valeria de Turris
- Center for Life Nano Science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Volker Middel
- Institute of Toxicology and Genetics (ITG), KIT, Karlsruhe, Germany
| | - Anne S Ulrich
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.,Institute of Organic Chemistry, KIT, Karlsruhe, Germany
| | - YuanPu Peter Di
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Maria Luisa Mangoni
- Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, Italy
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