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Koynarev VR, Borgos KKA, Kohlbrecher J, Porcar L, Nielsen JE, Lund R. Antimicrobial Peptides Increase Line Tension in Raft-Forming Lipid Membranes. J Am Chem Soc 2024. [PMID: 39018511 DOI: 10.1021/jacs.4c05377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/19/2024]
Abstract
The formation of phase separated membrane domains is believed to be essential for the function of the cell. The precise composition and physical properties of lipid bilayer domains play crucial roles in regulating protein activity and governing cellular processes. Perturbation of the domain structure in human cells can be related to neurodegenerative diseases and cancer. Lipid rafts are also believed to be essential in bacteria, potentially serving as targets for antibiotics. An important question is how the membrane domain structure is affected by bioactive and therapeutic molecules, such as surface-active peptides, which target cellular membranes. Here we focus on antimicrobial peptides (AMPs), crucial components of the innate immune system, to gain insights into their interaction with model lipid membranes containing domains. Using small-angle neutron/X-ray scattering (SANS/SAXS), we show that the addition of several natural AMPs (indolicidin, LL-37, magainin II, and aurein 2.2) causes substantial growth and restructuring of the domains, which corresponds to increased line tension. Contrast variation SANS and SAXS results demonstrate that the peptide inserts evenly in both phases, and the increased line tension can be related to preferential and concentration dependent thinning of the unsaturated membrane phase. We speculate that the lateral restructuring caused by the AMPs may have important consequences in affecting physiological functions of real cells. This work thus shines important light onto the complex interactions and lateral (re)organization in lipid membranes, which is relevant for a molecular understanding of diseases and the action of antibiotics.
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Affiliation(s)
| | | | - Joachim Kohlbrecher
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, Villigen 5232, Switzerland
| | - Lionel Porcar
- Institut Laue-Langevin, 71 Av. des Martyrs, 38000 Grenoble, France
| | | | - Reidar Lund
- Department of Chemistry, University of Oslo, Postboks 1033 Blindern, 0315 Oslo, Norway
- Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, Postboks 1033 Blindern, 0315 Oslo, Norway
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2
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Sidarta M, Lorente Martín AI, Monsalve A, Marinho Righetto G, Schäfer AB, Wenzel M. Lipid phase separation impairs membrane thickness sensing by the Bacillus subtilis sensor kinase DesK. Microbiol Spectr 2024; 12:e0392523. [PMID: 38717171 DOI: 10.1128/spectrum.03925-23] [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: 11/12/2023] [Accepted: 04/08/2024] [Indexed: 06/06/2024] Open
Abstract
Membrane fluidity and thickness have emerged as crucial factors for the activity of and resistance to several antimicrobials. However, the lack of tools to study membrane fluidity and, in particular, thickness in living bacteria limits our understanding of this interplay. The Bacillus subtilis histidine kinase/phosphatase DesK is a molecular sensor that directly detects membrane thickness. It controls activity of DesR, which regulates expression of the lipid desaturase Des, known for its role in cold adaptation and daptomycin susceptibility. We hypothesized that this property could be exploited to develop biosensors and reporters for antibiotic-induced changes in membrane fluidity and thickness. To test this, we designed three assays based on the des system: activation of the Pdes promoter as reporter for membrane thickening, localization of DesK-GFP(green-fluorescent protein) as proxy for rigidified membrane domains, and antibiotic sensitivity of des, desK, and desR deletion mutants as readout for the importance of membrane rigidification/thickening under the tested condition. While we could not confirm the suitability of the des system as reporter for antibiotic-induced changes in membrane thickness, we did observe that des expression is only activated by mild temperature shocks, likely due to partitioning of the sensor DesK into fluid membrane domains upon phase separation, precluding effective thickness sensing under harsh cold shock and antibiotic stress conditions. Similarly, we did not observe any sensitivity of the deletion mutants to either temperature or antibiotic stress, raising the question to what extent the des system contributes to fluidity adaptation under these conditions. IMPORTANCE The B. subtilis des system is a prime model for direct molecular membrane thickness sensor and, as such, has been well studied in vitro. Our study shows that our understanding of its function in vivo and its importance under temperature and antibiotic stress is still very limited. Specifically, our results suggest that (i) the des system senses very subtle membrane fluidity changes that escape detection by established fluidity reporters like laurdan; (ii) membrane thickness sensing by DesK is impaired by phase separation due to partitioning of the protein into the fluid phase; and (iii) fluidity adaptations by Des are too subtle to elicit growth defects under rigidifying conditions, raising the question of how much the des system contributes to adaptation of overall membrane fluidity.
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Affiliation(s)
- Margareth Sidarta
- Division of Chemical Biology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Centre for Antibiotic Resistance Research in Gothenburg (CARe), Gothenburg, Sweden
| | - Ana I Lorente Martín
- Division of Chemical Biology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Anuntxi Monsalve
- Division of Chemical Biology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Gabriela Marinho Righetto
- Division of Chemical Biology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Centre for Antibiotic Resistance Research in Gothenburg (CARe), Gothenburg, Sweden
| | - Ann-Britt Schäfer
- Division of Chemical Biology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Centre for Antibiotic Resistance Research in Gothenburg (CARe), Gothenburg, Sweden
| | - Michaela Wenzel
- Division of Chemical Biology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Centre for Antibiotic Resistance Research in Gothenburg (CARe), Gothenburg, Sweden
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3
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Chatterjee H, Mahapatra AJ, Zacharias M, Sengupta N. Helical reorganization in the context of membrane protein folding: Insights from simulations with bacteriorhodopsin (BR) fragments. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184333. [PMID: 38740122 DOI: 10.1016/j.bbamem.2024.184333] [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: 02/07/2024] [Revised: 04/20/2024] [Accepted: 05/09/2024] [Indexed: 05/16/2024]
Abstract
Membrane protein folding is distinct from folding of soluble proteins. Conformational acquisition in major membrane protein subclasses can be delineated into insertion and folding processes. An exception to the "two stage" folding, later developed to "three stage" folding, is observed within the last two helices in bacteriorhodopsin (BR), a system that serves as a model membrane protein. We employ a reductionist approach to understand interplay of molecular factors underlying the apparent defiance. Leveraging available solution NMR structures, we construct, sample in silico, and analyze partially (PIn) and fully inserted (FIn) BR membrane states. The membrane lateral C-terminal helix (CH) in PIn is markedly prone to transient structural distortions over microsecond timescales; a disorder prone region (DPR) is thereby identified. While clear transmembrane propensities are not acquired, the distortions induce alterations in local membrane curvature and area per lipid. Importantly, energetic decompositions reveal that overall, the N-terminal helix (NH) is thermodynamically more stable in the PIn. Higher overall stability of the FIn arises from favorable interactions between the NH and the CH. Our results establish lack of spontaneous transition of the PIn to the FIn, and attributes their partitioning to barriers that exceed those accessible with thermal fluctuations. This work paves the way for further detailed studies aimed at determining the thermo-kinetic roles of the initial five helices, or complementary external factors, in complete helical folding and insertion in BR. We comment that complementing such efforts with the growing field of machine learning assisted energy landscape searches may offer unprecedented insights.
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Affiliation(s)
- Hindol Chatterjee
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Anshuman J Mahapatra
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Martin Zacharias
- Center for Functional Protein Assemblies, TUM School of Natural Sciences Technical University Munich, Ernst-Otto-Fischer-Straße 8, 85748 Garching, Germany.
| | - Neelanjana Sengupta
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India.
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4
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Rzycki M, Drabik D. Multifaceted Activity of Fabimycin: Insights from Molecular Dynamics Studies on Bacterial Membrane Models. J Chem Inf Model 2024; 64:4204-4217. [PMID: 38733348 PMCID: PMC11134499 DOI: 10.1021/acs.jcim.4c00228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/29/2024] [Accepted: 04/30/2024] [Indexed: 05/13/2024]
Abstract
Membranes─cells' essential scaffolds─are valid molecular targets for substances with an antimicrobial effect. While certain substances, such as octenidine, have been developed to target membranes for antimicrobial purposes, the recently reported molecule, fabimycin (F2B)─a novel agent targeting drug-resistant Gram-negative bacteria─has not received adequate attention regarding its activity on membranes in the literature. The following study aims to investigate the effects of F2B on different bacterial membrane models, including simple planar bilayers and more complex bilayer systems that mimic the Escherichia coli shell equipped with double inner and outer bilayers. Our results show that F2B exhibited more pronounced interactions with bacterial membrane systems compared to the control PC system. Furthermore, we observed significant changes in local membrane property homeostasis in both the inner and outer membrane models, specifically in the case of lateral diffusion, membrane thickness, and membrane resilience (compressibility, tilt). Finally, our results showed that the effect of F2B differed in a complex system and a single membrane system. Our study provides new insights into the multifaceted activity of F2B, demonstrating its potential to disrupt bacterial membrane homeostasis, indicating that its activity extends the currently known mechanism of FabI enzyme inhibition. This disruption, coupled with the ability of F2B to penetrate the outer membrane layers, sheds new light on the behavior of this antimicrobial molecule. This highlights the importance of the interaction with the membrane, crucial in combating bacterial infections, particularly those caused by drug-resistant strains.
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Affiliation(s)
- Mateusz Rzycki
- Department of Biomedical Engineering, Wroclaw University of Science and Technology, Wroclaw 50-370, Poland
| | - Dominik Drabik
- Department of Biomedical Engineering, Wroclaw University of Science and Technology, Wroclaw 50-370, Poland
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5
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Dowaidar M. Uptake pathways of cell-penetrating peptides in the context of drug delivery, gene therapy, and vaccine development. Cell Signal 2024; 117:111116. [PMID: 38408550 DOI: 10.1016/j.cellsig.2024.111116] [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: 01/03/2024] [Revised: 02/19/2024] [Accepted: 02/21/2024] [Indexed: 02/28/2024]
Abstract
Cell-penetrating peptides have been extensively utilized for the purpose of facilitating the intracellular delivery of cargo that is impermeable to the cell membrane. The researchers have exhibited proficient delivery capabilities for oligonucleotides, thereby establishing cell-penetrating peptides as a potent instrument in the field of gene therapy. Furthermore, they have demonstrated a high level of efficiency in delivering several additional payloads. Cell penetrating peptides (CPPs) possess the capability to efficiently transport therapeutic molecules to specific cells, hence offering potential remedies for many illnesses. Hence, their utilization is imperative for the improvement of therapeutic vaccines. In contemporary studies, a plethora of cell-penetrating peptides have been unveiled, each characterized by its own distinct structural attributes and associated mechanisms. Although it is widely acknowledged that there are multiple pathways through which particles might be internalized, a comprehensive understanding of the specific mechanisms by which these particles enter cells has to be fully elucidated. The absorption of cell-penetrating peptides can occur through either direct translocation or endocytosis. However, it is worth noting that categories of cell-penetrating peptides are not commonly linked to specific entrance mechanisms. Furthermore, research has demonstrated that cell-penetrating peptides (CPPs) possess the capacity to enhance antigen uptake by cells and facilitate the traversal of various biological barriers. The primary objective of this work is to examine the mechanisms by which cell-penetrating peptides are internalized by cells and their significance in facilitating the administration of drugs, particularly in the context of gene therapy and vaccine development. The current study investigates the immunostimulatory properties of numerous vaccine components administered using different cell-penetrating peptides (CPPs). This study encompassed a comprehensive discussion on various topics, including the uptake pathways and mechanisms of cell-penetrating peptides (CPPs), the utilization of CPPs as innovative vectors for gene therapy, the role of CPPs in vaccine development, and the potential of CPPs for antigen delivery in the context of vaccine development.
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Affiliation(s)
- Moataz Dowaidar
- Bioengineering Department, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia; Interdisciplinary Research Center for Hydrogen Technologies and Carbon Management, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia; Biosystems and Machines Research Center, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia.
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6
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Park P, Matsubara DK, Barzotto DR, Lima FS, Chaimovich H, Marrink SJ, Cuccovia IM. Vesicle protrusion induced by antimicrobial peptides suggests common carpet mechanism for short antimicrobial peptides. Sci Rep 2024; 14:9701. [PMID: 38678109 PMCID: PMC11055889 DOI: 10.1038/s41598-024-60601-w] [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: 09/30/2023] [Accepted: 04/25/2024] [Indexed: 04/29/2024] Open
Abstract
Short-cationic alpha-helical antimicrobial peptides (SCHAMPs) are promising candidates to combat the growing global threat of antimicrobial resistance. They are short-sequenced, selective against bacteria, and have rapid action by destroying membranes. A full understanding of their mechanism of action will provide key information to design more potent and selective SCHAMPs. Molecular Dynamics (MD) simulations are invaluable tools that provide detailed insights into the peptide-membrane interaction at the atomic- and meso-scale level. We use atomistic and coarse-grained MD to look into the exact steps that four promising SCHAMPs-BP100, Decoralin, Neurokinin-1, and Temporin L-take when they interact with membranes. Following experimental set-ups, we explored the effects of SCHAMPs on anionic membranes and vesicles at multiple peptide concentrations. Our results showed all four peptides shared similar binding steps, initially binding to the membrane through electrostatic interactions and then flipping on their axes, dehydrating, and inserting their hydrophobic moieties into the membrane core. At higher concentrations, fully alpha-helical peptides induced membrane budding and protrusions. Our results suggest the carpet mode of action is fit for the description of SCHAMPs lysis activity and discuss the importance of large hydrophobic residues in SCHAMPs design and activity.
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Affiliation(s)
- Peter Park
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
- Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, 9747 AG, Groningen, the Netherlands
| | - Danilo K Matsubara
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Domenico R Barzotto
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Filipe S Lima
- Departamento de Química Fundamental, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, Recife, Brazil
| | - Hernan Chaimovich
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, 9747 AG, Groningen, the Netherlands.
| | - Iolanda M Cuccovia
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil.
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7
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Hrebonkin A, Afonin S, Nikitjuka A, Borysov OV, Leitis G, Babii O, Koniev S, Lorig T, Grage SL, Nick P, Ulrich AS, Jirgensons A, Komarov IV. Spiropyran-Based Photoisomerizable α-Amino Acid for Membrane-Active Peptide Modification. Chemistry 2024; 30:e202400066. [PMID: 38366887 DOI: 10.1002/chem.202400066] [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: 01/08/2024] [Revised: 02/11/2024] [Accepted: 02/12/2024] [Indexed: 02/18/2024]
Abstract
Photoisomerizable peptides are promising drug candidates in photopharmacology. While azobenzene- and diarylethene-containing photoisomerizable peptides have already demonstrated their potential in this regard, reports on the use of spiropyrans to photoregulate bioactive peptides are still scarce. This work focuses on the design and synthesis of a spiropyran-derived amino acid, (S)-2-amino-3-(6'-methoxy-1',3',3'-trimethylspiro-[2H-1-benzopyran-2,2'-indolin-6-yl])propanoic acid, which is suitable for the preparation of photoisomerizable peptides. The utility of this amino acid is demonstrated by incorporating it into the backbone of BP100, a known membrane-active peptide, and by examining the photoregulation of the membrane perturbation by the spiropyran-containing peptides. The toxicity of the peptides (against the plant cell line BY-2), their bacteriotoxicity (E. coli), and actin-auxin oscillator modulation ability were shown to be significantly dependent on the photoisomeric state of the spiropyran unit.
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Affiliation(s)
- Andrii Hrebonkin
- Karlsruhe Institute of Technology, POB 3640, 76021, Karlsruhe, Germany
- Enamine, Vul. Winstona Churchilla 78, 02094, Kyiv, Ukraine
| | - Sergii Afonin
- Karlsruhe Institute of Technology, POB 3640, 76021, Karlsruhe, Germany
| | - Anna Nikitjuka
- Enamine, Vul. Winstona Churchilla 78, 02094, Kyiv, Ukraine
- Latvian Institute of Organic Synthesis, Aizkraukles iela 21, 1006, Riga, Latvia
| | - Oleksandr V Borysov
- Enamine, Vul. Winstona Churchilla 78, 02094, Kyiv, Ukraine
- Latvian Institute of Organic Synthesis, Aizkraukles iela 21, 1006, Riga, Latvia
| | - Gundars Leitis
- Enamine, Vul. Winstona Churchilla 78, 02094, Kyiv, Ukraine
- Latvian Institute of Organic Synthesis, Aizkraukles iela 21, 1006, Riga, Latvia
| | - Oleg Babii
- Karlsruhe Institute of Technology, POB 3640, 76021, Karlsruhe, Germany
| | - Serhii Koniev
- Enamine, Vul. Winstona Churchilla 78, 02094, Kyiv, Ukraine
- Taras Shevchenko National University of Kyiv, Vul. Volodymyrska 60, 01601, Kyiv, Ukraine
| | - Theo Lorig
- Karlsruhe Institute of Technology, POB 3640, 76021, Karlsruhe, Germany
| | - Stephan L Grage
- Karlsruhe Institute of Technology, POB 3640, 76021, Karlsruhe, Germany
| | - Peter Nick
- Karlsruhe Institute of Technology, POB 3640, 76021, Karlsruhe, Germany
| | - Anne S Ulrich
- Karlsruhe Institute of Technology, POB 3640, 76021, Karlsruhe, Germany
| | - Aigars Jirgensons
- Latvian Institute of Organic Synthesis, Aizkraukles iela 21, 1006, Riga, Latvia
| | - Igor V Komarov
- Enamine, Vul. Winstona Churchilla 78, 02094, Kyiv, Ukraine
- Taras Shevchenko National University of Kyiv, Vul. Volodymyrska 60, 01601, Kyiv, Ukraine
- Lumobiotics, Auerstraße 2, 76227, Karlsruhe., Germany
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8
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Putri RA, Rohman MS, Swasono RT, Raharjo TJ. A novel synthetic peptide analog enhanced antibacterial activity of the frog-derived skin peptide wuchuanin-A1. J Biomol Struct Dyn 2023:1-11. [PMID: 37968993 DOI: 10.1080/07391102.2023.2281633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 11/04/2023] [Indexed: 11/17/2023]
Abstract
In recent years, there has been a growing focus on the development of novel antibacterial compounds for clinical applications, such as antimicrobial peptide (AMP). Among the developed AMP, wuchuanin-A1, a coil-shaped bioactive peptide derived from Odorrana wuchuanensis frog skin, has been reported to exhibit antibacterial, antifungal, and antioxidant activity, but there are limited studies on its potential as an antibacterial agent. Therefore, this study aims to molecularly modify the sequence of wuchuanin-A1 to enhance its antibacterial properties. The interaction of both the native and analog peptide with bacterial inner membranes was initially assessed using computational methods. Specific amino acid substitutions were then used to enhance the modified peptide's antibacterial efficacy, followed by several preliminary tests to evaluate its activity. This study bridges the gap in exploring the potential of wuchuanin-A1 for antibacterial purposes, providing insights into the design of effective antimicrobial agents.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
| | | | | | - Tri Joko Raharjo
- Department of Chemistry, Universitas Gadjah Mada, Bulaksumur, Indonesia
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9
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Bertelsen M, Lacey MM, Nichol T, Miller K. Mechanistic Insight into the Early Stages of Toroidal Pore Formation by the Antimicrobial Peptide Smp24. Pharmaceutics 2023; 15:2399. [PMID: 37896158 PMCID: PMC10610086 DOI: 10.3390/pharmaceutics15102399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/12/2023] [Accepted: 09/15/2023] [Indexed: 10/29/2023] Open
Abstract
The antimicrobial peptide Smp24, originally derived from the venom of Scorpio maurus palmatus, is a promising candidate for further drug development. However, before doing so, greater insight into the mechanism of action is needed to construct a reliable structure-activity relationship. The aim of this study was to specifically investigate the critical early stages of peptide-induced membrane disruption. Single-channel current traces were obtained via planar patch-clamp electrophysiology, with multiple types of pore-forming events observed, unlike those expected from the traditional, more rigid mechanistic models. To better understand the molecular-level structures of the peptide-pore assemblies underlying these observed conductance events, molecular dynamics simulations were used to investigate the peptide structure and orientation both before and during pore formation. The transition of the peptides to transmembrane-like states within disordered toroidal pores occurred due to a peptide-induced bilayer-leaflet asymmetry, explaining why pore stabilization does not always follow pore nucleation in the experimental observations. To fully grasp the structure-activity relationship of antimicrobial peptides, a more nuanced view of the complex and dynamic mechanistic behaviour must be adopted.
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Affiliation(s)
| | | | | | - Keith Miller
- Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield S1 1WB, UK
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10
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Hamley IW, Castelletto V. Small-angle scattering techniques for peptide and peptide hybrid nanostructures and peptide-based biomaterials. Adv Colloid Interface Sci 2023; 318:102959. [PMID: 37473606 DOI: 10.1016/j.cis.2023.102959] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/03/2023] [Accepted: 07/04/2023] [Indexed: 07/22/2023]
Abstract
The use of small-angle scattering (SAS) in the study of the self-assembly of peptides and peptide conjugates (lipopeptides, polymer-peptide conjugates and others) is reviewed, highlighting selected research that illustrates different methods and analysis techniques. Both small-angle x-ray scattering (SAXS) and small-angle neutron scattering (SANS) are considered along with examples that exploit their unique capabilities. For SAXS, this includes the ability to perform rapid measurements enabling high throughput or fast kinetic studies and measurements under dilute conditions. For SANS, contrast variation using H2O/D2O mixtures enables the study of peptides interacting with lipids and TR-SANS (time-resolved SANS) studies of exchange kinetics and/or peptide-induced structural changes. Examples are provided of studies measuring form factors of different self-assembled structures (micelles, fibrils, nanotapes, nanotubes etc) as well as structure factors from ordered phases (lyotropic mesophases), peptide gels and hybrid materials such as membranes formed by mixing peptides with polysaccharides or peptide/liposome mixtures. SAXS/WAXS (WAXS: wide-angle x-ray scattering) on peptides and peptide hybrids is also discussed, and the review concludes with a perspective on potential future directions for research in the field.
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Affiliation(s)
- Ian W Hamley
- Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, UK.
| | - Valeria Castelletto
- Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, UK
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11
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Vinutha AS, Rajasekaran R. Insight on the mechanism of hexameric Pseudin-4 against bacterial membrane-mimetic environment. J Comput Aided Mol Des 2023:10.1007/s10822-023-00516-2. [PMID: 37368161 DOI: 10.1007/s10822-023-00516-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 06/22/2023] [Indexed: 06/28/2023]
Abstract
As an alternative to antibiotics, Antimicrobial Peptides (AMPs) possess unique properties including cationic, amphipathic and their abundance in nature, but the exact characteristics of AMPs against bacterial membranes are still undetermined. To estimate the structural stability and functional activity of AMPs, the Pseudin AMPs (Pse-1, Pse-2, Pse-3, and Pse-4) from Hylid frog species, Pseudis paradoxa, an abundantly discovered source for AMPs were examined. We studied the intra-peptide interactions and thermal denaturation stability of peptides, as well as the geometrical parameters and secondary structure profiles of their conformational trajectories. On this basis, the peptides were screened out and the highly stable peptide, Pse-4 was subjected to membrane simulation in order to observe the changes in membrane curvature formed by Pse-4 insertion. Monomeric Pse-4 was found to initiate the membrane disruption; however, a stable multimeric form of Pse-4 might be competent to counterbalance the helix-coil transition and to resist the hydrophobic membrane environment. Eventually, hexameric Pse-4 on membrane simulation exhibited the hydrogen bond formation with E. coli bacterial membrane and thereby, leading to the formation of membrane spanning pore that allowed the entry of excess water molecules into the membrane shell, thus causing membrane deformation. Our report points out the mechanism of Pse-4 peptide against the bacterial membrane for the first time. Relatively, Pse-4 works on the barrel stave model against E. coli bacterial membrane; hence it might act as a good therapeutic scaffold in the treatment of multi-drug resistant bacterial strains.
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Affiliation(s)
- A S Vinutha
- Quantitative Biology Lab, Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT, Deemed to be University), Vellore, Tamil Nadu, India
| | - R Rajasekaran
- Quantitative Biology Lab, Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT, Deemed to be University), Vellore, Tamil Nadu, India.
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12
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Roy A, Sarangi NK, Ghosh S, Prabhakaran A, Keyes TE. Leaflet by Leaflet Synergistic Effects of Antimicrobial Peptides on Bacterial and Mammalian Membrane Models. J Phys Chem Lett 2023; 14:3920-3928. [PMID: 37075204 PMCID: PMC10150393 DOI: 10.1021/acs.jpclett.3c00119] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Antimicrobial peptides (AMPs) offer significant hope in the fight against antibiotic resistance. Operating via a mechanism different from that of antibiotics, they target the microbial membrane and ideally should damage it without impacting mammalian cells. Here, the interactions of two AMPs, magainin 2 and PGLa, and their synergistic effects on bacterial and mammalian membrane models were studied using electrochemical impedance spectroscopy, atomic force microscopy (AFM), and fluorescence correlation spectroscopy. Toroidal pore formation was observed by AFM when the two AMPs were combined, while individually AMP effects were confined to the exterior leaflet of the bacterial membrane analogue. Using microcavity-supported lipid bilayers, the diffusivity of each bilayer leaflet could be studied independently, and we observed that combined, the AMPs penetrate both leaflets of the bacterial model but individually each peptide had a limited impact on the proximal leaflet of the bacterial model. The impact of AMPs on a ternary, mammalian mimetic membrane was much weaker.
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Affiliation(s)
- Arpita Roy
- School of Chemical Sciences and National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9, Ireland
| | - Nirod Kumar Sarangi
- School of Chemical Sciences and National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9, Ireland
| | - Surajit Ghosh
- School of Chemical Sciences and National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9, Ireland
| | - Amrutha Prabhakaran
- School of Chemical Sciences and National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9, Ireland
| | - Tia E Keyes
- School of Chemical Sciences and National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9, Ireland
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13
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MacDermott-Opeskin HI, Wilson KA, O'Mara ML. The Impact of Antimicrobial Peptides on the Acinetobacter baumannii Inner Membrane Is Modulated by Lipid Polyunsaturation. ACS Infect Dis 2023; 9:815-826. [PMID: 36920795 DOI: 10.1021/acsinfecdis.2c00530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
The Gram-negative pathogen Acinetobacter baumannii is a primary contributor to nosocomial multi-drug-resistant (MDR) infections. To combat the rise of MDR infections, novel features of A. baumannii need to be considered for the development of new treatment options. One such feature is the preferential scavenging of exogenous lipids, including host-derived polyunsaturated fatty acids (PUFAs), for membrane phospholipid synthesis. These alterations in membrane composition impact both the lipid chemistry and the membrane biophysical properties. In this work we examine how antimicrobial peptides (AMPs) interact with the inner membranes of A. baumannii in the presence and absence of polyunsaturated phospholipids. Using coarse-grained molecular dynamics simulations of complex A. baumannii inner membrane models derived from lipidomes of bacteria grown in the presence and absence of PUFAs, we examine the impact of the adsorption of four prototypical AMPs (CAMEL, LL-37, pexiganan, and magainin-2) on the membrane biophysical properties. Our simulations reveal that the impact of AMP adsorption on the membrane biophysical properties was dependent on both the membrane composition and the specific AMP involved. Both lipid headgroup charge and tail unsaturation played important roles in driving the interactions that occurred both within the membrane and between the membrane and AMPs. The changes to the membrane biophysical properties also showed a complex relationship with the AMP's physical properties, such as AMP charge, chain length, and charge-to-mass ratio. Cumulatively, this work highlights the importance of studying AMPs using a complex membrane environment and provides insights into the mechanistic action of AMPs in polyunsaturated lipid-rich bacterial membranes.
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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
| | - Katie A Wilson
- Research School of Chemistry, College of Science, The Australian National University, Canberra, ACT 2601, Australia.,Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL A1C 5S7 Canada
| | - Megan L O'Mara
- Research School of Chemistry, College of Science, The Australian National University, Canberra, ACT 2601, Australia.,Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
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14
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Ramirez RX, Campbell O, Pradhan AJ, Atilla-Gokcumen GE, Monje-Galvan V. Modeling the molecular fingerprint of protein-lipid interactions of MLKL on complex bilayers. Front Chem 2023; 10:1088058. [PMID: 36712977 PMCID: PMC9877227 DOI: 10.3389/fchem.2022.1088058] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 12/28/2022] [Indexed: 01/14/2023] Open
Abstract
Lipids, the structural part of membranes, play important roles in biological functions. However, our understanding of their implication in key cellular processes such as cell division and protein-lipid interaction is just emerging. This is the case for molecular interactions in mechanisms of cell death, where the role of lipids for protein localization and subsequent membrane permeabilization is key. For example, during the last stage of necroptosis, the mixed lineage kinase domain-like (MLKL) protein translocates and, eventually, permeabilizes the plasma membrane (PM). This process results in the leakage of cellular content, inducing an inflammatory response in the microenvironment that is conducive to oncogenesis and metastasis, among other pathologies that exhibit inflammatory activity. This work presents insights from long all-atom molecular dynamics (MD) simulations of complex membrane models for the PM of mammalian cells with an MLKL protein monomer. Our results show that the binding of the protein is initially driven by the electrostatic interactions of positively charged residues. The protein bound conformation modulates lipid recruitment to the binding site, which changes the local lipid environment recruiting PIP lipids and cholesterol, generating a unique fingerprint. These results increase our knowledge of protein-lipid interactions at the membrane interface in the context of molecular mechanisms of the necroptotic pathway, currently under investigation as a potential treatment target in cancer and inflamatory diseases.
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Affiliation(s)
- Ricardo X. Ramirez
- Department of Chemical and Biological Engineering, School of Engineering and Applied Sciences, University at Buffalo, Buffalo, NY, United States
| | - Oluwatoyin Campbell
- Department of Chemical and Biological Engineering, School of Engineering and Applied Sciences, University at Buffalo, Buffalo, NY, United States
| | - Apoorva J. Pradhan
- Department of Chemistry, College of Arts and Sciences, University at Buffalo, Buffalo, NY, United States
| | - G. Ekin Atilla-Gokcumen
- Department of Chemistry, College of Arts and Sciences, University at Buffalo, Buffalo, NY, United States
| | - Viviana Monje-Galvan
- Department of Chemical and Biological Engineering, School of Engineering and Applied Sciences, University at Buffalo, Buffalo, NY, United States,*Correspondence: Viviana Monje-Galvan,
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15
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The potential of antifungal peptide Sesquin as natural food preservative. Biochimie 2022; 203:51-64. [PMID: 35395327 DOI: 10.1016/j.biochi.2022.03.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 12/16/2022]
Abstract
Sesquin is a wide spectrum antimicrobial peptide displaying a remarkable activity on fungi. Contrarily to most antimicrobial peptides, it presents an overall negative charge. In the present study, we elucidate the molecular basis of its mode of action towards biomimetic membranes by NMR and MD experiments. While a specific recognition of phosphatidylethanolamine (PE) might explain its activity in a variety of different organisms (including bacteria), a further interaction with ergosterol accounts for its strong antifungal activity. NMR data reveal a charge gradient along its amide protons allowing the peptide to reach the membrane phosphate groups despite its negative charge. Subsequently, the peptide gets structured inside the bilayer, reducing its order. MD simulations predict that its activity is retained in conditions commonly used for food preservation: low temperatures, high pressure, or the presence of electric field pulses, making Sesquin a good candidate as food preservative.
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16
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Roque-Borda CA, Bento da Silva P, Rodrigues MC, Di Filippo LD, Duarte JL, Chorilli M, Vicente EF, Garrido SS, Rogério Pavan F. Pharmaceutical nanotechnology: Antimicrobial peptides as potential new drugs against WHO list of critical, high, and medium priority bacteria. Eur J Med Chem 2022; 241:114640. [PMID: 35970075 DOI: 10.1016/j.ejmech.2022.114640] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 07/12/2022] [Accepted: 07/27/2022] [Indexed: 12/29/2022]
Abstract
Nanobiotechnology is a relatively unexplored area that has, nevertheless, shown relevant results in the fight against some diseases. Antimicrobial peptides (AMPs) are biomacromolecules with potential activity against multi/extensively drug-resistant bacteria, with a lower risk of generating bacterial resistance. They can be considered an excellent biotechnological alternative to conventional drugs. However, the application of several AMPs to biological systems is hampered by their poor stability and lifetime, inactivating them completely. Therefore, nanotechnology plays an important role in the development of new AMP-based drugs, protecting and carrying the bioactive to the target. This is the first review article on the different reported nanosystems using AMPs against bacteria listed on the WHO priority list. The current shortage of information implies a nanobiotechnological potential to obtain new drugs or repurpose drugs based on the AMP-drug synergistic effect.
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Affiliation(s)
- Cesar Augusto Roque-Borda
- São Paulo State University (UNESP), School of Pharmaceutical Sciences, Tuberculosis Research Laboratory, Araraquara, São Paulo, CEP 14800-903, Brazil; Universidad Católica de Santa María, Vicerrectorado de Investigación, Facultad de Ciencias Farmacéuticas Bioquímicas y Biotecnológicas, Brazil
| | - Patricia Bento da Silva
- Laboratory of Nanobiotechnology, Department of Genetics and Morphology, Institute of Biological Sciences, University of Brasilia, Brasilia, Brazil
| | - Mosar Corrêa Rodrigues
- Laboratory of Nanobiotechnology, Department of Genetics and Morphology, Institute of Biological Sciences, University of Brasilia, Brasilia, Brazil
| | - Leonardo Delello Di Filippo
- São Paulo State University (UNESP), School of Pharmaceutical Sciences, Department of Drugs and Medicines, Araraquara, São Paulo, CEP 14800-903, Brazil
| | - Jonatas L Duarte
- São Paulo State University (UNESP), School of Pharmaceutical Sciences, Department of Drugs and Medicines, Araraquara, São Paulo, CEP 14800-903, Brazil
| | - Marlus Chorilli
- São Paulo State University (UNESP), School of Pharmaceutical Sciences, Department of Drugs and Medicines, Araraquara, São Paulo, CEP 14800-903, Brazil
| | - Eduardo Festozo Vicente
- São Paulo State University (UNESP), School of Sciences and Engineering, Tupã, São Paulo, CEP 17602-496, Brazil
| | - Saulo Santesso Garrido
- São Paulo State University (UNESP), Institute of Chemistry, Araraquara, São Paulo, CEP 14801-902, Brazil
| | - Fernando Rogério Pavan
- São Paulo State University (UNESP), School of Pharmaceutical Sciences, Tuberculosis Research Laboratory, Araraquara, São Paulo, CEP 14800-903, Brazil.
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17
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Mescola A, Ragazzini G, Facci P, Alessandrini A. The potential of AFM in studying the role of the nanoscale amphipathic nature of (lipo)-peptides interacting with lipid bilayers. NANOTECHNOLOGY 2022; 33:432001. [PMID: 35830770 DOI: 10.1088/1361-6528/ac80c9] [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: 11/30/2021] [Accepted: 07/13/2022] [Indexed: 06/15/2023]
Abstract
Antimicrobial peptides (AMPs) and lipopeptides (LPs) represent very promising molecules to fight resistant bacterial infections due to their broad-spectrum of activity, their first target, i.e. the bacterial membrane, and the rapid bactericidal action. For both types of molecules, the action mechanism starts from the membrane of the pathogen agents, producing a disorganization of their phase structure or the formation of pores of different size altering their permeability. This mechanism of action is based on physical interactions more than on a lock-and-key recognition event and it is difficult for the pathogens to rapidly develop an effective resistance. Very small differences in the sequence of both AMPs and LPs might lead to very different effects on the target membrane. Therefore, a correct understanding of their mechanism of action is required with the aim of developing new synthetic peptides, analogues of the natural ones, with specific and more powerful bactericidal activity. Atomic force microscopy (AFM), with its high resolution and the associated force spectroscopy resource, provides a valuable technique to investigate the reorganization of lipid bilayers exposed to antimicrobial or lipopeptides. Here, we present AFM results obtained by ours and other groups on the action of AMPs and LPs on supported lipid bilayers (SLBs) of different composition. We also consider data obtained by fluorescence microscopy to compare the AFM data with another technique which can be used on different lipid bilayer model systems such as SLBs and giant unilamellar vesicles. The outcomes here presented highlight the powerful of AFM-based techniques in detecting nanoscale peptide-membrane interactions and strengthen their use as an exceptional complementary tool toin vivoinvestigations. Indeed, the combination of these approaches can help decipher the mechanisms of action of different antimicrobials and lipopeptides at both the micro and nanoscale levels, and to design new and more efficient antimicrobial compounds.
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Affiliation(s)
- Andrea Mescola
- CNR-Nanoscience Institute-S3, Via Campi 213/A, I-41125, Modena, Italy
| | - Gregorio Ragazzini
- Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, Via Campi 213/A, I-41125, Modena, Italy
| | - Paolo Facci
- CNR-Ibf, Via De Marini 6, I-16149, Genova, Italy
| | - Andrea Alessandrini
- CNR-Nanoscience Institute-S3, Via Campi 213/A, I-41125, Modena, Italy
- Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, Via Campi 213/A, I-41125, Modena, Italy
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18
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Zhou M, Zou X, Cheng K, Zhong S, Su Y, Wu T, Tao Y, Cong L, Yan B, Jiang Y. The role of cell-penetrating peptides in potential anti-cancer therapy. Clin Transl Med 2022; 12:e822. [PMID: 35593206 PMCID: PMC9121317 DOI: 10.1002/ctm2.822] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 03/28/2022] [Accepted: 04/04/2022] [Indexed: 12/19/2022] Open
Abstract
Due to the complex physiological structure, microenvironment and multiple physiological barriers, traditional anti-cancer drugs are severely restricted from reaching the tumour site. Cell-penetrating peptides (CPPs) are typically made up of 5-30 amino acids, and can be utilised as molecular transporters to facilitate the passage of therapeutic drugs across physiological barriers. Up to now, CPPs have widely been used in many anti-cancer treatment strategies, serving as an excellent potential choice for oncology treatment. However, their drawbacks, such as the lack of cell specificity, short duration of action, poor stability in vivo, compatibility problems (i.e. immunogenicity), poor therapeutic efficacy and formation of unwanted metabolites, have limited their further application in cancer treatment. The cellular uptake mechanisms of CPPs involve mainly endocytosis and direct penetration, but still remain highly controversial in academia. The CPPs-based drug delivery strategy could be improved by clever design or chemical modifications to develop the next-generation CPPs with enhanced cell penetration capability, stability and selectivity. In addition, some recent advances in targeted cell penetration that involve CPPs provide some new ideas to optimise CPPs.
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Affiliation(s)
- Meiling Zhou
- The Key Laboratory of Model Animal and Stem Cell Biology in Hunan Province, Hunan Normal University, Changsha, Hunan, China.,School of Medicine, Hunan Normal University, Changsha, Hunan, China
| | - Xi Zou
- The Key Laboratory of Model Animal and Stem Cell Biology in Hunan Province, Hunan Normal University, Changsha, Hunan, China.,School of Medicine, Hunan Normal University, Changsha, Hunan, China
| | - Kexin Cheng
- The Key Laboratory of Model Animal and Stem Cell Biology in Hunan Province, Hunan Normal University, Changsha, Hunan, China.,School of Medicine, Hunan Normal University, Changsha, Hunan, China
| | - Suye Zhong
- The Key Laboratory of Model Animal and Stem Cell Biology in Hunan Province, Hunan Normal University, Changsha, Hunan, China.,School of Medicine, Hunan Normal University, Changsha, Hunan, China
| | - Yangzhou Su
- The Key Laboratory of Model Animal and Stem Cell Biology in Hunan Province, Hunan Normal University, Changsha, Hunan, China.,School of Medicine, Hunan Normal University, Changsha, Hunan, China
| | - Tao Wu
- The Key Laboratory of Model Animal and Stem Cell Biology in Hunan Province, Hunan Normal University, Changsha, Hunan, China.,School of Medicine, Hunan Normal University, Changsha, Hunan, China
| | - Yongguang Tao
- Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Department of Pathology, Xiangya Hospital, School of Basic Medicine, Central South University, Changsha, Hunan, China
| | - Li Cong
- The Key Laboratory of Model Animal and Stem Cell Biology in Hunan Province, Hunan Normal University, Changsha, Hunan, China.,School of Medicine, Hunan Normal University, Changsha, Hunan, China
| | - Bin Yan
- Department of Pathology, The Second Clinical Medical College of Jinan University, The First Affiliated Hospital Southern University of Science and Technology, Shenzhen People's Hospital, Shenzhen, China
| | - Yiqun Jiang
- The Key Laboratory of Model Animal and Stem Cell Biology in Hunan Province, Hunan Normal University, Changsha, Hunan, China.,School of Medicine, Hunan Normal University, Changsha, Hunan, China
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19
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Gupta R, Sharma VK, Gupta J, Ghosh SK. 1,3 Dialkylated Imidazolium Ionic Liquid Causes Interdigitated Domains in a Phospholipid Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:3412-3421. [PMID: 35263113 DOI: 10.1021/acs.langmuir.1c03160] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Amphiphilic imidazolium-based ionic liquids (ILs) have proven their efficacy in altering the membrane integrity and dynamics. The present article investigates the phase-separated domains in a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) membrane induced by 1,3 dialkylated imidazolium IL. Isotherm measurements on DPPC monolayers formed at the air-water interface have shown a decrease in the mean molecular area with the addition of this IL. The positive value of the excess Gibbs free energy of mixing indicates an unfavorable mixing of the IL into the lipid. This leads to IL-induced phase-separated domains in the multilayer of the lipid confirmed by the occurrence of two sets of equidistance peaks in the X-ray reflectivity data. The electron density profile along the surface normal obtained by the swelling method shows the bilayer thickness of the newly formed IL-rich phase to be substantially lower (∼34 Å) than the DPPC phase (∼45.8 Å). This IL-rich phase has been confirmed to be interdigitated, showing an enhanced electron density in the tail region due to the overlapping hydrocarbon chains. Differential scanning calorimetry measurements showed that the incorporation of IL enhances the fluidity of the lipid bilayer. Therefore, the study indicates the formation of an interdigitated phase with a lower order compared to the gel phase in the DPPC membrane supplemented with the IL.
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Affiliation(s)
- Ritika Gupta
- Department of Physics, School of Natural Sciences, Shiv Nadar University, NH 91, Tehsil Dadri, G. B. Nagar, Greater Noida, Uttar Pradesh 201314, India
| | - Veerendra K Sharma
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Jyoti Gupta
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Sajal K Ghosh
- Department of Physics, School of Natural Sciences, Shiv Nadar University, NH 91, Tehsil Dadri, G. B. Nagar, Greater Noida, Uttar Pradesh 201314, India
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20
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Franco LR, Park P, Chaimovich H, Coutinho K, Cuccovia IM, Lima FS. Simulations reveal that antimicrobial BP100 induces local membrane thinning, slows lipid dynamics and favors water penetration. RSC Adv 2022; 12:4573-4588. [PMID: 35425494 PMCID: PMC8981376 DOI: 10.1039/d1ra06267k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 01/26/2022] [Indexed: 11/21/2022] Open
Abstract
MD simulations reveal that BP100 peptide induces local membrane thinning and negative curvature, slows lipid dynamics and increases the water life time in the lipid hydrophobic core and transmembrane water transport in the direction of the peptide.
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Affiliation(s)
| | - Peter Park
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Hernan Chaimovich
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Kaline Coutinho
- Instituto de Física, Universidade de São Paulo, São Paulo, Brazil
| | - Iolanda M. Cuccovia
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Filipe S. Lima
- Departamento de Química Fundamental, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, Recife, Brazil
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21
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Roy S, Sarkhel S, Bisht D, Hanumantharao SN, Rao S, Jaiswal A. Antimicrobial Mechanisms of Biomaterials: From Macro to Nano. Biomater Sci 2022; 10:4392-4423. [DOI: 10.1039/d2bm00472k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Overcoming the global concern of antibiotic resistance is one of the biggest challenge faced by scientists today and the key to tackle this issue of emerging infectious diseases is the...
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22
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Juhl DW, Glattard E, Aisenbrey C, Bechinger B. Antimicrobial peptides: mechanism of action and lipid-mediated synergistic interactions within membranes. Faraday Discuss 2021; 232:419-434. [PMID: 34533138 DOI: 10.1039/d0fd00041h] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Biophysical and structural studies of peptide-lipid interactions, peptide topology and dynamics have changed our view of how antimicrobial peptides insert and interact with membranes. Clearly, both peptides and lipids are highly dynamic, and change and mutually adapt their conformation, membrane penetration and detailed morphology on a local and a global level. As a consequence, peptides and lipids can form a wide variety of supramolecular assemblies in which the more hydrophobic sequences preferentially, but not exclusively, adopt transmembrane alignments and have the potential to form oligomeric structures similar to those suggested by the transmembrane helical bundle model. In contrast, charged amphipathic sequences tend to stay intercalated at the membrane interface. Although the membranes are soft and can adapt, at increasing peptide density they cause pronounced disruptions of the phospholipid fatty acyl packing. At even higher local or global concentrations the peptides cause transient membrane openings, rupture and ultimately lysis. Interestingly, mixtures of peptides such as magainin 2 and PGLa, which are stored and secreted naturally as a cocktail, exhibit considerably enhanced antimicrobial activities when investigated together in antimicrobial assays and also in pore forming experiments applied to biophysical model systems. Our most recent investigations reveal that these peptides do not form stable complexes but act by specific lipid-mediated interactions and the nanoscale properties of phospholipid bilayers.
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Affiliation(s)
- Dennis W Juhl
- Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, 4, rue Blaise Pascal, 67070 Strasbourg, France.
| | - Elise Glattard
- Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, 4, rue Blaise Pascal, 67070 Strasbourg, France.
| | - Christopher Aisenbrey
- Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, 4, rue Blaise Pascal, 67070 Strasbourg, France.
| | - Burkhard Bechinger
- Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, 4, rue Blaise Pascal, 67070 Strasbourg, France. .,Institut Universitaire de France, France
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23
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Nunes LGP, Reichert T, Machini MT. His-Rich Peptides, Gly- and His-Rich Peptides: Functionally Versatile Compounds with Potential Multi-Purpose Applications. Int J Pept Res Ther 2021. [DOI: 10.1007/s10989-021-10302-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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24
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Lee OS, Madjet ME, Mahmoud KA. Antibacterial Mechanism of Multifunctional MXene Nanosheets: Domain Formation and Phase Transition in Lipid Bilayer. NANO LETTERS 2021; 21:8510-8517. [PMID: 34402623 DOI: 10.1021/acs.nanolett.1c01986] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
MXenes, two-dimensional metal carbides or nitrides with multifunctional surfaces, are one of the most promising antibacterial nanoscale materials. However, their putative bactericidal mechanism is elusive. To study their bactericidal mechanism, we investigated the interaction between a MXene nanosheet and a model bacterial membrane by molecular dynamics simulations and found that an adsorbed MXene on a membrane surface induced a local phase transition in a domain where the fluidity of the phospholipid in this domain at room temperature was comparable with that of the gel phase. The domain also showed a denser and thinner phospholipid membrane structure than the peripheral phospholipids. By comparing it with our previous experiments of the bactericidal activity of MXenes, we proposed the leakage of intercellular molecules at the phase boundary defects as a possible bactericidal mechanism of MXenes that leads to cell lysis. This study provides a useful model for tailoring new bactericidal nanomaterials.
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Affiliation(s)
- One-Sun Lee
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, PO Box 34110 Doha, Qatar
| | - Mohamed E Madjet
- Max-Planck-Institut für Physik, Komplexer Systeme, Nöthnitzer Straße 38, 01187 Dresden, Germany
| | - Khaled A Mahmoud
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, PO Box 34110 Doha, Qatar
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25
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Cell Surface Binding and Lipid Interactions behind Chemotherapy-Drug-Induced Ion Pore Formation in Membranes. MEMBRANES 2021; 11:membranes11070501. [PMID: 34209282 PMCID: PMC8304557 DOI: 10.3390/membranes11070501] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/17/2021] [Accepted: 06/25/2021] [Indexed: 11/17/2022]
Abstract
Chemotherapy drugs (CDs) disrupt the lipid membrane’s insulation properties by inducing stable ion pores across bilayer membranes. The underlying molecular mechanisms behind pore formation have been revealed in this study using several methods that confirm molecular interactions and detect associated energetics of drugs on the cell surface in general and in lipid bilayers in particular. Liposome adsorption and cell surface binding of CD colchicine has been demonstrated experimentally. Buffer dissolved CDs were considerably adsorbed in the incubated phospholipid liposomes, measured using the patented ‘direct detection method’. The drug adsorption process is regulated by the membrane environment, demonstrated in cholesterol-containing liposomes. We then detailed the phenomenology and energetics of the low nanoscale dimension cell surface (membrane) drug distribution, using atomic force microscopy (AFM) imaging what addresses the surface morphology and measures adhesion force (reducible to adhesive energy). Liposome adsorption and cell surface binding data helped model the cell surface drug distribution. The underlying molecular interactions behind surface binding energetics of drugs have been addressed in silico numerical computations (NCs) utilizing the screened Coulomb interactions among charges in a drug–drug/lipid cluster. Molecular dynamics (MD) simulations of the CD-lipid complexes detected primarily important CD-lipid electrostatic and van der Waals (vdW) interaction energies. From the energetics point of view, both liposome and cell surface membrane adsorption of drugs are therefore obvious findings. Colchicine treated cell surface AFM images provide a few important phenomenological conclusions, such as drugs bind generally with the cell surface, bind independently as well as in clusters of various sizes in random cell surface locations. The related adhesion energy decreases with increasing drug cluster size before saturating for larger clusters. MD simulation detected electrostatic and vdW and NC-derived charge-based interactions explain molecularly of the cause of cell surface binding of drugs. The membrane binding/association of drugs may help create drug–lipid complexes with specific energetics and statistically lead to the creation of ion channels. We reveal here crucial molecular understanding and features of the pore formation inside lipid membranes that may be applied universally for most of the pore-forming existing agents and novel candidate drugs.
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26
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Zabara M, Ren Q, Amenitsch H, Salentinig S. Bioinspired Antimicrobial Coatings from Peptide-Functionalized Liquid Crystalline Nanostructures. ACS APPLIED BIO MATERIALS 2021; 4:5295-5303. [PMID: 35007010 DOI: 10.1021/acsabm.1c00415] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Surface-associated microbial infections and contaminations are a major challenge in various fields including the food and health sectors. This study demonstrates the design of antimicrobial coatings based on the self-assembly of the food-grade amphiphilic lipid glycerol monooleate with the human cathelicidin-derived antimicrobial peptide LL-37. Structural properties of the coating and their alterations with composition were studied using advanced experimental methods including synchrotron grazing-incidence small-angle X-ray scattering and ellipsometry. The integration of the LL-37 and its potential release from the nanostructured films into the surrounding solution was characterized with confocal Raman microscopy. Additional biological evaluation studies with clinically relevant bacterial strains, namely, Pseudomonas aeruginosa (Gram-negative) and Staphylococcus aureus (Gram-positive), were performed to investigate the antimicrobial activity of the coatings. Significant killing activity of the coating was found against both bacterial strains. The presented findings contribute to the fundamental understanding of lipid-peptide self-assembly on the surface and may open up a promising strategy for designing simple, sustainable antimicrobial coatings for medical and food applications.
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Affiliation(s)
- Mahsa Zabara
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland
| | - Qun Ren
- Laboratory for Biointerfaces, Department Materials Meet Life, Empa Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Heinz Amenitsch
- Institute for Inorganic Chemistry, Graz University of Technology, Stremayergasse 9/V, 8010 Graz, Austria
| | - Stefan Salentinig
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland
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27
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Steinberg R, Koch HG. The largely unexplored biology of small proteins in pro- and eukaryotes. FEBS J 2021; 288:7002-7024. [PMID: 33780127 DOI: 10.1111/febs.15845] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/11/2021] [Accepted: 03/26/2021] [Indexed: 12/29/2022]
Abstract
The large abundance of small open reading frames (smORFs) in prokaryotic and eukaryotic genomes and the plethora of smORF-encoded small proteins became only apparent with the constant advancements in bioinformatic, genomic, proteomic, and biochemical tools. Small proteins are typically defined as proteins of < 50 amino acids in prokaryotes and of less than 100 amino acids in eukaryotes, and their importance for cell physiology and cellular adaptation is only beginning to emerge. In contrast to antimicrobial peptides, which are secreted by prokaryotic and eukaryotic cells for combatting pathogens and competitors, small proteins act within the producing cell mainly by stabilizing protein assemblies and by modifying the activity of larger proteins. Production of small proteins is frequently linked to stress conditions or environmental changes, and therefore, cells seem to use small proteins as intracellular modifiers for adjusting cell metabolism to different intra- and extracellular cues. However, the size of small proteins imposes a major challenge for the cellular machinery required for protein folding and intracellular trafficking and recent data indicate that small proteins can engage distinct trafficking pathways. In the current review, we describe the diversity of small proteins in prokaryotes and eukaryotes, highlight distinct and common features, and illustrate how they are handled by the protein trafficking machineries in prokaryotic and eukaryotic cells. Finally, we also discuss future topics of research on this fascinating but largely unexplored group of proteins.
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Affiliation(s)
- Ruth Steinberg
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Germany
| | - Hans-Georg Koch
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Germany
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Bechinger B, Juhl DW, Glattard E, Aisenbrey C. Revealing the Mechanisms of Synergistic Action of Two Magainin Antimicrobial Peptides. FRONTIERS IN MEDICAL TECHNOLOGY 2020; 2:615494. [PMID: 35047895 PMCID: PMC8757784 DOI: 10.3389/fmedt.2020.615494] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 11/30/2020] [Indexed: 12/18/2022] Open
Abstract
The study of peptide-lipid and peptide-peptide interactions as well as their topology and dynamics using biophysical and structural approaches have changed our view how antimicrobial peptides work and function. It has become obvious that both the peptides and the lipids arrange in soft supramolecular arrangements which are highly dynamic and able to change and mutually adapt their conformation, membrane penetration, and detailed morphology. This can occur on a local and a global level. This review focuses on cationic amphipathic peptides of the magainin family which were studied extensively by biophysical approaches. They are found intercalated at the membrane interface where they cause membrane thinning and ultimately lysis. Interestingly, mixtures of two of those peptides namely magainin 2 and PGLa which occur naturally as a cocktail in the frog skin exhibit synergistic enhancement of antimicrobial activities when investigated together in antimicrobial assays but also in biophysical experiments with model membranes. Detailed dose-response curves, presented here for the first time, show a cooperative behavior for the individual peptides which is much increased when PGLa and magainin are added as equimolar mixture. This has important consequences for their bacterial killing activities and resistance development. In membranes that carry unsaturations both peptides align parallel to the membrane surface where they have been shown to arrange into mesophases involving the peptides and the lipids. This supramolecular structuration comes along with much-increased membrane affinities for the peptide mixture. Because this synergism is most pronounced in membranes representing the bacterial lipid composition it can potentially be used to increase the therapeutic window of pharmaceutical formulations.
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Affiliation(s)
- Burkhard Bechinger
- University of Strasbourg/CNRS, UMR7177, Institut de Chimie de Strasbourg, Strasbourg, France
- Institut Universitaire de France (IUF), Paris, France
| | - Dennis Wilkens Juhl
- University of Strasbourg/CNRS, UMR7177, Institut de Chimie de Strasbourg, Strasbourg, France
| | - Elise Glattard
- University of Strasbourg/CNRS, UMR7177, Institut de Chimie de Strasbourg, Strasbourg, France
| | - Christopher Aisenbrey
- University of Strasbourg/CNRS, UMR7177, Institut de Chimie de Strasbourg, Strasbourg, France
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29
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Flores‐Romero H, Ros U, Garcia‐Saez AJ. Pore formation in regulated cell death. EMBO J 2020; 39:e105753. [PMID: 33124082 PMCID: PMC7705454 DOI: 10.15252/embj.2020105753] [Citation(s) in RCA: 107] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/13/2020] [Accepted: 10/06/2020] [Indexed: 12/21/2022] Open
Abstract
The discovery of alternative signaling pathways that regulate cell death has revealed multiple strategies for promoting cell death with diverse consequences at the tissue and organism level. Despite the divergence in the molecular components involved, membrane permeabilization is a common theme in the execution of regulated cell death. In apoptosis, the permeabilization of the outer mitochondrial membrane by BAX and BAK releases apoptotic factors that initiate the caspase cascade and is considered the point of no return in cell death commitment. Pyroptosis and necroptosis also require the perforation of the plasma membrane at the execution step, which involves Gasdermins in pyroptosis, and MLKL in the case of necroptosis. Although BAX/BAK, Gasdermins and MLKL share certain molecular features like oligomerization, they form pores in different cellular membranes via distinct mechanisms. Here, we compare and contrast how BAX/BAK, Gasdermins, and MLKL alter membrane permeability from a structural and biophysical perspective and discuss the general principles of membrane permeabilization in the execution of regulated cell death.
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Affiliation(s)
- Hector Flores‐Romero
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Uris Ros
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Ana J Garcia‐Saez
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
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Zamani E, Johnson TJ, Chatterjee S, Immethun C, Sarella A, Saha R, Dishari SK. Cationic π-Conjugated Polyelectrolyte Shows Antimicrobial Activity by Causing Lipid Loss and Lowering Elastic Modulus of Bacteria. ACS APPLIED MATERIALS & INTERFACES 2020; 12:49346-49361. [PMID: 33089982 PMCID: PMC8926324 DOI: 10.1021/acsami.0c12038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Cationic, π-conjugated oligo-/polyelectrolytes (CCOEs/CCPEs) have shown great potential as antimicrobial materials to fight against antibiotic resistance. In this work, we treated wild-type and ampicillin-resistant (amp-resistant) Escherichia coli (E. coli) with a promising cationic, π-conjugated polyelectrolyte (P1) with a phenylene-based backbone and investigated the resulting morphological, mechanical, and compositional changes of the outer membrane of bacteria in great detail. The cationic quaternary amine groups of P1 led to electrostatic interactions with negatively charged moieties within the outer membrane of bacteria. Using atomic force microscopy (AFM), high-resolution transmission electron microscopy (TEM), we showed that due to this treatment, the bacterial outer membrane became rougher, decreased in stiffness/elastic modulus (AFM nanoindentation), formed blebs, and released vesicles near the cells. These evidences, in addition to increased staining of the P1-treated cell membrane by lipophilic dye Nile Red (confocal laser scanning microscopy (CLSM)), suggested loosening/disruption of packing of the outer cell envelope and release and exposure of lipid-based components. Lipidomics and fatty acid analysis confirmed a significant loss of phosphate-based outer membrane lipids and fatty acids, some of which are critically needed to maintain cell wall integrity and mechanical strength. Lipidomics and UV-vis analysis also confirmed that the extracellular vesicles released upon treatment (AFM) are composed of lipids and cationic P1. Such surface alterations (vesicle/bleb formation) and release of lipids/fatty acids upon treatment were effective enough to inhibit further growth of E. coli cells without completely disintegrating the cells and have been known as a defense mechanism of the cells against cationic antimicrobial agents.
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Affiliation(s)
- Ehsan Zamani
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Tyler J. Johnson
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Shyambo Chatterjee
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Cheryl Immethun
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Anandakumar Sarella
- Nebraska Center for Materials and Nanoscience, Voelte-Keegan Nanoscience Research Center, University of Nebraska-Lincoln, Lincoln, NE 68588-0298, United States
| | - Rajib Saha
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Shudipto Konika Dishari
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
- Corresponding author’s ; Phone: 402-472-7537
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31
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Sikkema HR, van den Noort M, Rheinberger J, de Boer M, Krepel ST, Schuurman-Wolters GK, Paulino C, Poolman B. Gating by ionic strength and safety check by cyclic-di-AMP in the ABC transporter OpuA. SCIENCE ADVANCES 2020; 6:6/47/eabd7697. [PMID: 33208376 PMCID: PMC7673798 DOI: 10.1126/sciadv.abd7697] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 10/01/2020] [Indexed: 05/02/2023]
Abstract
(Micro)organisms are exposed to fluctuating environmental conditions, and adaptation to stress is essential for survival. Increased osmolality (hypertonicity) causes outflow of water and loss of turgor and is dangerous if the cell is not capable of rapidly restoring its volume. The osmoregulatory adenosine triphosphate-binding cassette transporter OpuA restores the cell volume by accumulating large amounts of compatible solute. OpuA is gated by ionic strength and inhibited by the second messenger cyclic-di-AMP, a molecule recently shown to affect many cellular processes. Despite the master regulatory role of cyclic-di-AMP, structural and functional insights into how the second messenger regulates (transport) proteins on the molecular level are lacking. Here, we present high-resolution cryo-electron microscopy structures of OpuA and in vitro activity assays that show how the osmoregulator OpuA is activated by high ionic strength and how cyclic-di-AMP acts as a backstop to prevent unbridled uptake of compatible solutes.
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Affiliation(s)
- Hendrik R Sikkema
- Department of Biochemistry, Membrane Enzymology Group, Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, Netherlands
| | - Marco van den Noort
- Department of Biochemistry, Membrane Enzymology Group, Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, Netherlands
| | - Jan Rheinberger
- Department of Biochemistry, Structural Biology Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, Netherlands
| | - Marijn de Boer
- Department of Biochemistry, Membrane Enzymology Group, Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, Netherlands
| | - Sabrina T Krepel
- Department of Biochemistry, Membrane Enzymology Group, Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, Netherlands
| | - Gea K Schuurman-Wolters
- Department of Biochemistry, Membrane Enzymology Group, Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, Netherlands
| | - Cristina Paulino
- Department of Biochemistry, Structural Biology Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, Netherlands.
| | - Bert Poolman
- Department of Biochemistry, Membrane Enzymology Group, Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, Netherlands.
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32
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Schäfer AB, Wenzel M. A How-To Guide for Mode of Action Analysis of Antimicrobial Peptides. Front Cell Infect Microbiol 2020; 10:540898. [PMID: 33194788 PMCID: PMC7604286 DOI: 10.3389/fcimb.2020.540898] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 09/18/2020] [Indexed: 12/11/2022] Open
Abstract
Antimicrobial peptides (AMPs) are a promising alternative to classical antibiotics in the fight against multi-resistant bacteria. They are produced by organisms from all domains of life and constitute a nearly universal defense mechanism against infectious agents. No drug can be approved without information about its mechanism of action. In order to use them in a clinical setting, it is pivotal to understand how AMPs work. While many pore-forming AMPs are well-characterized in model membrane systems, non-pore-forming peptides are often poorly understood. Moreover, there is evidence that pore formation may not happen or not play a role in vivo. It is therefore imperative to study how AMPs interact with their targets in vivo and consequently kill microorganisms. This has been difficult in the past, since established methods did not provide much mechanistic detail. Especially, methods to study membrane-active compounds have been scarce. Recent advances, in particular in microscopy technology and cell biological labeling techniques, now allow studying mechanisms of AMPs in unprecedented detail. This review gives an overview of available in vivo methods to investigate the antibacterial mechanisms of AMPs. In addition to classical mode of action classification assays, we discuss global profiling techniques, such as genomic and proteomic approaches, as well as bacterial cytological profiling and other cell biological assays. We cover approaches to determine the effects of AMPs on cell morphology, outer membrane, cell wall, and inner membrane properties, cellular macromolecules, and protein targets. We particularly expand on methods to examine cytoplasmic membrane parameters, such as composition, thickness, organization, fluidity, potential, and the functionality of membrane-associated processes. This review aims to provide a guide for researchers, who seek a broad overview of the available methodology to study the mechanisms of AMPs in living bacteria.
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Affiliation(s)
| | - Michaela Wenzel
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
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Paternò GM, Bondelli G, Sakai VG, Sesti V, Bertarelli C, Lanzani G. The Effect of an Intramembrane Light-Actuator on the Dynamics of Phospholipids in Model Membranes and Intact Cells. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:11517-11527. [PMID: 32903010 DOI: 10.1021/acs.langmuir.0c01846] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The noncovalent intercalation of amphiphilic molecules in the lipid membrane can be exploited to modulate efficiently the physical status of the membrane. Such effects are largely employed in a range of applications, spanning from drug-delivery to therapeutics. In this context, we have very recently developed an intramembrane photo-actuator consisting of an amphiphilic azobenzene molecule, namely ZIAPIN2. The selective photo-isomerization occurring in the lipid bilayer induces a photo-triggered change in the membrane thickness and capacitance, eventually permitting to evoke light-induced neuronal firing both in vitro and in vivo. Here, we present a study on the dynamical perturbation in the lipid membrane caused by ZIAPIN2 and its vehicle solvent, dimethyl sulfoxide. Effects on the dynamics occurring in the picosecond time range and at the molecular level are probed using quasi-elastic neutron scattering. By coupling experiments carried out both on model membranes and intact cells, we found that DMSO leads to a general retardation of the dynamics within a more dynamically ordered landscape, a result that we attribute to the dehydration at the interface. On the other hand, ZIAPIN2 partitioning produces a general softening of the bilayer owing to its interaction with the lipids. These data are in agreement with our recent studies, which indicate that the efficacy of ZIAPIN2 in triggering cellular signalling stems from its ability to mechanically perturb the bilayer as a whole, by forming light-sensitive membrane spanning dimers.
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Affiliation(s)
- Giuseppe M Paternò
- Center for Nano Science and Technology, Istituto Italiano di Tecnologia, Via Pascoli 10, 20133 Milano, Italy
| | - Gaia Bondelli
- Center for Nano Science and Technology, Istituto Italiano di Tecnologia, Via Pascoli 10, 20133 Milano, Italy
| | - Victoria Garcia Sakai
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0QX, U.K
| | - Valentina Sesti
- Dipartimento di Chimica, Materiali e Ingegneria Chimica ″Giulio Natta″, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy
| | - Chiara Bertarelli
- Dipartimento di Chimica, Materiali e Ingegneria Chimica ″Giulio Natta″, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy
| | - Guglielmo Lanzani
- Center for Nano Science and Technology, Istituto Italiano di Tecnologia, Via Pascoli 10, 20133 Milano, Italy
- Dipartimento di Fisica, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy
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Mercer DK, O'Neil DA. Innate Inspiration: Antifungal Peptides and Other Immunotherapeutics From the Host Immune Response. Front Immunol 2020; 11:2177. [PMID: 33072081 PMCID: PMC7533533 DOI: 10.3389/fimmu.2020.02177] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 08/10/2020] [Indexed: 12/17/2022] Open
Abstract
The purpose of this review is to describe antifungal therapeutic candidates in preclinical and clinical development derived from, or directly influenced by, the immune system, with a specific focus on antimicrobial peptides (AMP). Although the focus of this review is AMP with direct antimicrobial effects on fungi, we will also discuss compounds with direct antifungal activity, including monoclonal antibodies (mAb), as well as immunomodulatory molecules that can enhance the immune response to fungal infection, including immunomodulatory AMP, vaccines, checkpoint inhibitors, interferon and colony stimulating factors as well as immune cell therapies. The focus of this manuscript will be a non-exhaustive review of antifungal compounds in preclinical and clinical development that are based on the principles of immunology and the authors acknowledge the incredible amount of in vitro and in vivo work that has been conducted to develop such therapeutic candidates.
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Souza F, Fornasier F, Carvalho A, Silva B, Lima M, Pimentel A. Polymer-coated gold nanoparticles and polymeric nanoparticles as nanocarrier of the BP100 antimicrobial peptide through a lung surfactant model. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113661] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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36
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Mahlapuu M, Björn C, Ekblom J. Antimicrobial peptides as therapeutic agents: opportunities and challenges. Crit Rev Biotechnol 2020; 40:978-992. [PMID: 32781848 DOI: 10.1080/07388551.2020.1796576] [Citation(s) in RCA: 209] [Impact Index Per Article: 52.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The rapid development of microbial resistance to conventional antibiotics has accelerated efforts to find anti-infectives with a novel mode-of-action, which are less prone to bacterial resistance. Intense nonclinical and clinical research is today ongoing to evaluate antimicrobial peptides (AMPs) as potential next-generation antibiotics. Currently, multiple AMPs are assessed in late-stage clinical trials, not only as novel anti-infective drugs, but also as innovative product candidates for immunomodulation, promotion of wound healing, and prevention of post-operative scars. The efforts to translate AMP-based research findings into pharmaceutical product candidates are expected to accelerate in coming years due to technological advancements in multiple areas, including an improved understanding of the mechanism-of-action of AMPs, smart formulation strategies, and advanced chemical synthesis protocols. At the same time, it is recognized that cytotoxicity, low metabolic stability due to sensitivity to proteolytic degradation, and limited oral bioavailability are some of the key weaknesses of AMPs. Furthermore, the pricing and reimbursement environment for new antimicrobial products remains as a major barrier to the commercialization of AMPs.
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Affiliation(s)
- Margit Mahlapuu
- Promore Pharma AB, Karolinska Institutet Science Park, Solna, Sweden
| | | | - Jonas Ekblom
- Promore Pharma AB, Karolinska Institutet Science Park, Solna, Sweden
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Bioinformatic Analysis of 1000 Amphibian Antimicrobial Peptides Uncovers Multiple Length-Dependent Correlations for Peptide Design and Prediction. Antibiotics (Basel) 2020; 9:antibiotics9080491. [PMID: 32784626 PMCID: PMC7459754 DOI: 10.3390/antibiotics9080491] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/29/2020] [Accepted: 08/03/2020] [Indexed: 12/18/2022] Open
Abstract
Amphibians are widely distributed on different continents, except for the polar regions. They are important sources for the isolation, purification and characterization of natural compounds, including peptides with various functions. Innate immune antimicrobial peptides (AMPs) play a critical role in warding off invading pathogens, such as bacteria, fungi, parasites, and viruses. They may also have other biological functions such as endotoxin neutralization, chemotaxis, anti-inflammation, and wound healing. This article documents a bioinformatic analysis of over 1000 amphibian antimicrobial peptides registered in the Antimicrobial Peptide Database (APD) in the past 18 years. These anuran peptides were discovered in Africa, Asia, Australia, Europe, and America from 1985 to 2019. Genomic and peptidomic studies accelerated the discovery pace and underscored the necessity in establishing criteria for peptide entry into the APD. A total of 99.9% of the anuran antimicrobial peptides are less than 50 amino acids with an average length of 24 and a net charge of +2.5. Interestingly, the various amphibian peptide families (e.g., temporins, brevinins, esculentins) can be connected through multiple length-dependent relationships. With an increase in length, peptide net charge increases, while the hydrophobic content decreases. In addition, glycine, leucine, lysine, and proline all show linear correlations with peptide length. These correlations improve our understanding of amphibian peptides and may be useful for prediction and design of new linear peptides with potential applications in treating infectious diseases, cancer and diabetes.
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Membrane interactions in drug delivery: Model cell membranes and orthogonal techniques. Adv Colloid Interface Sci 2020; 281:102177. [PMID: 32417568 DOI: 10.1016/j.cis.2020.102177] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 03/05/2020] [Accepted: 05/07/2020] [Indexed: 01/22/2023]
Abstract
To generate the desired effect in the human body, the active pharmaceutical ingredient usually needs to interact with a receptor located on the cell membrane or inside the cell. Thus, understanding membrane interactions is of great importance when it comes to the development and testing of new drug molecules or new drug delivery systems. Nowadays, there is a tremendous selection of both model cell membranes and of techniques that can be used to characterize interactions between selected model cell membranes and a drug molecule, an excipient, or a drug delivery system. Having such a wide selection of model cell membranes and techniques available makes it sometimes challenging to select the optimal combination for a specific study. Furthermore, it is difficult to compare results obtained using different model cell membranes and techniques, and not all in vitro studies translate as well to an estimation of the in vivo biological activity or understanding of mode of action. This review provides an overview of the available lipid bilayer-based model cell membranes and of the most widely employed techniques for studying membrane interactions. Finally, the need for employing complimentary characterization techniques in order to acquire more reliable and in-depth information is highlighted.
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Downing R, Volpe Bossa G, May S. Saddle-curvature instability of lipid bilayer induced by amphipathic peptides: a molecular model. SOFT MATTER 2020; 16:5032-5043. [PMID: 32452495 DOI: 10.1039/d0sm00499e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Amphipathic peptides that partition into lipid bilayers affect the curvature elastic properties of their host. Some of these peptides are able to shift the Gaussian modulus to positive values, thus triggering an instability with respect to the formation of saddle curvatures. To characterize the generic aspects of the underlying mechanism, we employ a molecular lipid model that accounts for the interfacial tension between the polar and apolar regions of the membrane, for interactions between the lipid headgroups, and for the energy to stretch or compress the hydrocarbon chains. Peptides are modeled as cylinders that partition into the host membrane in a parallel orientation where they diminish the space available to the lipid headgroups and chains. The penetration depth into the membrane is determined by the angular size of the peptide's hydrophilic region. We demonstrate that only peptides with a small angular size of their hydrophilic region have an intrinsic tendency to render the Gaussian modulus more positive, and we identify conditions at which the Gaussian modulus adopts a positive sign upon increasing the peptide concentration. Our model allows us to also incorporate electrostatic interactions between cationic peptides and anionic lipids on the level of the linear Debye-Hückel model. We show that electrostatic interactions tend to shift the Gaussian modulus toward more positive values. Steric and electrostatic lipid-peptide interactions jointly decrease the effective interaction strength in the headgroup region of the host membrane thus suggesting a generic mechanisms of how certain amphipathic peptides are able to induce the formation of saddle curvatures.
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Affiliation(s)
- Rachel Downing
- Department of Physics, North Dakota State University, Fargo North Dakota 58108-6050, USA
| | - Guilherme Volpe Bossa
- Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences, São José do Rio Preto, SP 15054-000, Brazil.
| | - Sylvio May
- Department of Physics, North Dakota State University, Fargo North Dakota 58108-6050, USA
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Effect of AMPs MSI-78 and BP100 on the lipid acyl chains of 2H-labeled intact Gram positive bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183199. [DOI: 10.1016/j.bbamem.2020.183199] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/05/2020] [Accepted: 01/15/2020] [Indexed: 01/30/2023]
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41
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Bhatt Mitra J, Sharma VK, Mukherjee A, Garcia Sakai V, Dash A, Kumar M. Ubiquicidin-Derived Peptides Selectively Interact with the Anionic Phospholipid Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:397-408. [PMID: 31793791 DOI: 10.1021/acs.langmuir.9b03243] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Ubiquicidin (UBI)/ribosomal protein S30 (RS30) is an intracellular protein with antimicrobial activities against various pathogens. UBI (29-41) and UBI (31-38) are two crucial peptides derived from Ubiquicidin, which have shown potential as infection imaging probes. Here, we report the interactions of UBI-derived peptides with anionic and zwitterionic phospholipid membranes. Our isothermal titration calorimetry results show that both peptides selectively interact with the anionic phospholipid membrane (a model bacterial membrane) and reside mainly on the membrane surface. The interaction of UBI-derived peptides with the anionic phospholipid membrane is exothermic and driven by both enthalpy (ΔH) and entropy (ΔS), with the entropic term TΔS being greater than ΔH. This large entropic term can be a result of the aggregation of the anionic vesicles, which is confirmed by dynamic light scattering (DLS) measurements. DLS data show that vesicle aggregation is enhanced with increasing peptide-to-lipid molar ratios (P/L) and is found to be more pronounced in the case of UBI (29-41). DLS results are found to be consistent with independent transmission measurements. To study the effects of UBI-derived peptides on the microscopic dynamics of the model bacterial membrane, quasielastic neutron scattering (QENS) measurements have been carried out. The QENS results show that both peptides restrict the lateral motion of the lipid within the leaflet. UBI (29-41) acts as a stronger stiffening agent, hindering the lateral diffusion of lipids more efficiently than UBI (31-38). To our knowledge, this is the first report illustrating the mechanism of interaction of UBI-derived peptides with model membranes. This study also has implications for the improvement and design of antimicrobial peptide-based infection imaging probes.
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Affiliation(s)
| | | | - Archana Mukherjee
- Homi Bhabha National Institute , Anushaktinagar , Mumbai 400094 , India
| | - V Garcia Sakai
- ISIS Facility, Science and Technology Facilities Council , Rutherford Appleton Laboratory , Didcot OX11 0QX , U.K
| | - Ashutosh Dash
- Homi Bhabha National Institute , Anushaktinagar , Mumbai 400094 , India
| | - Mukesh Kumar
- Homi Bhabha National Institute , Anushaktinagar , Mumbai 400094 , India
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Singh M, Kumar V, Sikka K, Thakur R, Harioudh MK, Mishra DP, Ghosh JK, Siddiqi MI. Computational Design of Biologically Active Anticancer Peptides and Their Interactions with Heterogeneous POPC/POPS Lipid Membranes. J Chem Inf Model 2019; 60:332-341. [DOI: 10.1021/acs.jcim.9b00348] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Maninder Singh
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
| | - Vikash Kumar
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
| | - Kamakshi Sikka
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
| | - Ravi Thakur
- Endocrinology Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
| | - Munesh Kumar Harioudh
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
| | - Durga Prasad Mishra
- Endocrinology Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
| | - Jimut Kanti Ghosh
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
| | - Mohammad Imran Siddiqi
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
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Salnikov ES, Aisenbrey C, Pokrandt B, Brügger B, Bechinger B. Structure, Topology, and Dynamics of Membrane-Inserted Polypeptides and Lipids by Solid-State NMR Spectroscopy: Investigations of the Transmembrane Domains of the DQ Beta-1 Subunit of the MHC II Receptor and of the COP I Protein p24. Front Mol Biosci 2019; 6:83. [PMID: 31608287 PMCID: PMC6769064 DOI: 10.3389/fmolb.2019.00083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/23/2019] [Indexed: 01/04/2023] Open
Abstract
MHC class II receptors carry important function in adaptive immunity and their malfunctioning is associated with diabetes type I, chronic inflammatory diseases and other autoimmune diseases. The protein assembles from the DQ alpha-1 and DQ beta-1 subunits where the transmembrane domains of these type I membrane proteins have been shown to be involved in homo- and heterodimer formation. Furthermore, the DQ alpha 1 chain carries a sequence motif that has been first identified in the context of p24, a protein involved in the formation of COPI vesicles of the intracellular transport machinery, to specifically interact with sphingomyelin-C18 (SM-C18). Here we investigated the membrane interactions and dynamics of DQ beta-1 in liquid crystalline POPC phospholipid bilayers by oriented 15N solid-state NMR spectroscopy. The 15N resonances are indicative of a helical tilt angle of the membrane anchor sequence around 20°. Two populations can be distinguished by their differential dynamics probably corresponding the DQ beta-1 mono- and homodimer. Whereas, this equilibrium is hardly affected by the addition of 5 mole% SM-C18 a single population is visible in DMPC lipid bilayers suggesting that the lipid saturation is an important parameter. Furthermore, the DQ alpha-1, DQ beta-1 and p24 transmembrane helical domains were reconstituted into POPC or POPC/SM-C18 lipid bilayers where the fatty acyl chain of either the phosphatidylcholine or of the sphingolipid have been deuterated. Interestingly in the presence of both sphingolipid and polypeptide a strong decrease in the innermost membrane order of the POPC palmitoyl chain is observed, an effect that is strongest for DQ beta-1. In contrast, for the first time the polypeptide interactions were monitored by deuteration of the stearoyl chain of SM-C18. The resulting 2H solid-state NMR spectra show an increase in order for p24 and DQ alpha-1 which both carry the SM recognition motif. Thereby the data are suggestive that SM-C18 together with the transmembrane domains form structures imposing positive curvature strain on the surrounding POPC lipids. This effect is attenuated when SM-C18 is recognized by the protein.
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Affiliation(s)
- Evgeniy S Salnikov
- Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, Strasbourg, France
| | | | - Bianca Pokrandt
- Biochemiezentrum der Universität Heidelberg, Heidelberg, Germany
| | - Britta Brügger
- Biochemiezentrum der Universität Heidelberg, Heidelberg, Germany
| | - Burkhard Bechinger
- Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, Strasbourg, France
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Greene JR, Merrett KL, Heyert AJ, Simmons LF, Migliori CM, Vogt KC, Castro RS, Phillips PD, Baker JL, Lindberg GE, Fox DT, Del Sesto RE, Koppisch AT. Scope and efficacy of the broad-spectrum topical antiseptic choline geranate. PLoS One 2019; 14:e0222211. [PMID: 31527873 PMCID: PMC6748422 DOI: 10.1371/journal.pone.0222211] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/23/2019] [Indexed: 11/18/2022] Open
Abstract
Choline geranate (also described as Choline And GEranic acid, or CAGE) has been developed as a novel biocompatible antiseptic material capable of penetrating skin and aiding the transdermal delivery of co-administered antibiotics. The antibacterial properties of CAGE were analyzed against 24 and 72 hour old biofilms of 11 clinically isolated ESKAPE pathogens (defined as Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter sp, respectively), including multidrug resistant (MDR) isolates. CAGE was observed to eradicate in vitro biofilms at concentrations as low as 3.56 mM (0.156% v:v) in as little as 2 hours, which represents both an improved potency and rate of biofilm eradication relative to that reported for most common standard-of-care topical antiseptics in current use. In vitro time-kill studies on 24 hour old Staphylococcus aureus biofilms indicate that CAGE exerts its antibacterial effect upon contact and a 0.1% v:v solution reduced biofilm viability by over three orders of magnitude (a 3log10 reduction) in 15 minutes. Furthermore, disruption of the protective layer of exopolymeric substances in mature biofilms of Staphylococcus aureus by CAGE (0.1% v:v) was observed in 120 minutes. Insight into the mechanism of action of CAGE was provided with molecular modeling studies alongside in vitro antibiofilm assays. The geranate ion and geranic acid components of CAGE are predicted to act in concert to integrate into bacterial membranes, affect membrane thinning and perturb membrane homeostasis. Taken together, our results show that CAGE demonstrates all properties required of an effective topical antiseptic and the data also provides insight into how its observed antibiofilm properties may manifest.
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Affiliation(s)
- Joshua R. Greene
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Kahla L. Merrett
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Alexanndra J. Heyert
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Lucas F. Simmons
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Camille M. Migliori
- Department of Chemistry, Dixie State University, St. George, UT, United States of America
| | - Kristen C. Vogt
- Department of Chemistry, The College of New Jersey, Ewing, NJ, United States of America
| | - Rebeca S. Castro
- Department of Chemistry, The College of New Jersey, Ewing, NJ, United States of America
| | - Paul D. Phillips
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Joseph L. Baker
- Department of Chemistry, The College of New Jersey, Ewing, NJ, United States of America
| | - Gerrick E. Lindberg
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
- Center for Materials Interfaces in Research and Application, Northern Arizona University, Flagstaff, AZ, United States of America
| | - David T. Fox
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, United States of America
| | - Rico E. Del Sesto
- Department of Chemistry, Dixie State University, St. George, UT, United States of America
| | - Andrew T. Koppisch
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
- Center for Materials Interfaces in Research and Application, Northern Arizona University, Flagstaff, AZ, United States of America
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Structural insights into the AapA1 toxin of Helicobacter pylori. Biochim Biophys Acta Gen Subj 2019; 1864:129423. [PMID: 31476357 DOI: 10.1016/j.bbagen.2019.129423] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 08/12/2019] [Accepted: 08/28/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND We previously reported the identification of the aapA1/IsoA1 locus as part of a new family of toxin-antitoxin (TA) systems in the human pathogen Helicobacter pylori. AapA1 belongs to type I TA bacterial toxins, and both its mechanism of action towards the membrane and toxicity features are still unclear. METHODS The biochemical characterization of the AapA1 toxic peptide was carried out using plasmid-borne expression and mutational approaches to follow its toxicity and localization. Biophysical properties of the AapA1 interaction with lipid membranes were studied by solution and solid-state NMR spectroscopy, plasmon waveguide resonance (PWR) and molecular modeling. RESULTS We show that despite a low hydrophobic index, this toxin has a nanomolar affinity to the prokaryotic membrane. NMR spectroscopy reveals that the AapA1 toxin is structurally organized into three distinct domains: a positively charged disordered N-terminal domain (D), a single α-helix (H), and a basic C-terminal domain (R). The R domain interacts and destabilizes the membrane, while the H domain adopts a transmembrane conformation. These results were confirmed by alanine scanning of the minimal sequence required for toxicity. CONCLUSION Our results have shown that specific amino acid residues along the H domain, as well as the R domain, are essential for the toxicity of the AapA1 toxin. GENERAL SIGNIFICANCE Untangling and understanding the mechanism of action of small membrane-targeting toxins are difficult, but nevertheless contributes to a promising search and development of new antimicrobial drugs.
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Aisenbrey C, Salnikov ES, Bechinger B. Solid-State NMR Investigations of the MHC II Transmembrane Domains: Topological Equilibria and Lipid Interactions. J Membr Biol 2019; 252:371-384. [PMID: 31187155 DOI: 10.1007/s00232-019-00071-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 05/25/2019] [Indexed: 10/26/2022]
Abstract
The major histocompatibility complex class II (MHC II) membrane proteins are key players in the adaptive immune response. An aberrant function of these molecules is associated with a large number of autoimmune diseases such as diabetes type I and chronic inflammatory diseases. The MHC class II is assembled from DQ alpha 1 and DQ beta 1 which come together as a heterodimer through GXXXG-mediated protein-protein interactions and a highly specific protein-sphingomyelin-C18 interaction motif located on DQA1. This association can have important consequences in regulating the function of these membrane proteins. Here, we investigated the structure and topology of the DQA1 and DQB1 transmembrane helical domains by CD-, oriented 2H and 15N solid-state NMR spectroscopies. The spectra at peptide-to-lipid ratios of 0.5 to 2 mol% are indicative of a topological equilibrium involving a helix crossing the membrane with a tilt angle of about 20° and another transmembrane topology with around 30° tilt. The latter is probably representing a dimer. Furthermore, at the lowest peptide-to-lipid ratio, a third polypeptide population becomes obvious. Interestingly, the DQB1 and to a lesser extent the DQA1 transmembrane helical domains exhibit a strong fatty acyl chain disordering effect on the inner segments of the 2H-labelled palmitoyl chain of POPC bilayers. This phosphatidylcholine disordering requires the presence of sphingomyelin-C18 suggesting that the ensemble of transmembrane polypeptide and sphingolipid exerts positive curvature strain.
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Affiliation(s)
- Christopher Aisenbrey
- Institut de Chimie, Université de Strasbourg/CNRS, UMR7177, 4, Rue Blaise Pascal, 67070, Strasbourg, France
| | - Evgeniy S Salnikov
- Institut de Chimie, Université de Strasbourg/CNRS, UMR7177, 4, Rue Blaise Pascal, 67070, Strasbourg, France
| | - Burkhard Bechinger
- Institut de Chimie, Université de Strasbourg/CNRS, UMR7177, 4, Rue Blaise Pascal, 67070, Strasbourg, France.
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Dennison SR, Hauß T, Badiani K, Harris F, Phoenix DA. Biophysical investigation into the antibacterial action of modelin-5-NH 2. SOFT MATTER 2019; 15:4215-4226. [PMID: 31074477 DOI: 10.1039/c8sm02374c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Modelin-5-CONH2 (M5-NH2) is a synthetic antimicrobial peptide, which was found to show potent activity against Bacillus subtilis (minimum lethal concentration = 8.47 μM) and to bind strongly to membranes of the organism (Kd = 10.44 μM). The peptide adopted high levels of amphiphilic α-helical structure in the presence of these membranes (>50%), which led to high levels of insertion (Δπ ≥ 8.0 mN m-1). M5-NH2 showed high affinity for anionic lipid (Kd = 7.46 μM) and zwitterionic lipid (Kd = 14.7 μM), which drove insertion into membranes formed from these lipids (Δπ = 11.5 and 3.5 mN m-1, respectively). Neutron diffraction studies showed that M5-NH2 inserted into B. subtilis membranes with its N-terminal residue, L16, located 5.5 Å from the membrane centre, in the acyl chain region of these membranes, and promoted a reduction in membrane thickness of circa 1.8 Å or 5% of membrane width. Insertion into B. subtilis membranes by the peptide also promoted other effects associated with membrane thinning, including increases in membrane surface area (Cs-1 decreases) and fluidity (ΔGmix > 0 to ΔGmix < 0). Membrane insertion and thinning by M5-NH2 induced high levels of lysis (>55%), and it is speculated that the antibacterial action of the peptide may involve the toroidal pore, carpet or tilted-type mechanism of membrane permeabilization.
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Affiliation(s)
- Sarah R Dennison
- School of Pharmacy and Biological Sciences, University of Central Lancashire, Preston PR1 2HE, UK
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Aisenbrey C, Marquette A, Bechinger B. The Mechanisms of Action of Cationic Antimicrobial Peptides Refined by Novel Concepts from Biophysical Investigations. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1117:33-64. [PMID: 30980352 DOI: 10.1007/978-981-13-3588-4_4] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Even 30 years after the discovery of magainins, biophysical and structural investigations on how these peptides interact with membranes can still bear surprises and add new interesting detail to how these peptides exert their antimicrobial action. Early on, using oriented solid-state NMR spectroscopy, it was found that the amphipathic helices formed by magainins are active when being oriented parallel to the membrane surface. More recent investigations indicate that this in-planar alignment is also found when PGLa and magainin in combination exert synergistic pore-forming activities, where studies on the mechanism of synergistic interaction are ongoing. In a related manner, the investigation of dimeric antimicrobial peptide sequences has become an interesting topic of research which bears promise to refine our views how antimicrobial action occurs. The molecular shape concept has been introduced to explain the effects of lipids and peptides on membrane morphology, locally and globally, and in particular of cationic amphipathic helices that partition into the membrane interface. This concept has been extended in this review to include more recent ideas on soft membranes that can adapt to external stimuli including membrane-disruptive molecules. In this manner, the lipids can change their shape in the presence of low peptide concentrations, thereby maintaining the bilayer properties. At higher peptide concentrations, phase transitions occur which lead to the formation of pores and membrane lytic processes. In the context of the molecular shape concept, the properties of lipopeptides, including surfactins, are shortly presented, and comparisons with the hydrophobic alamethicin sequence are made.
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Affiliation(s)
| | - Arnaud Marquette
- Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, Strasbourg, France
| | - Burkhard Bechinger
- Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, Strasbourg, France. .,Faculté de chimie, Institut le Bel, Strasbourg, France.
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Cohen BE. Membrane Thickness as a Key Factor Contributing to the Activation of Osmosensors and Essential Ras Signaling Pathways. Front Cell Dev Biol 2018; 6:76. [PMID: 30087894 PMCID: PMC6066546 DOI: 10.3389/fcell.2018.00076] [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: 06/25/2018] [Indexed: 12/17/2022] Open
Abstract
The cell membrane provides a functional link between the external environment and the replicating DNA genome by using ligand-gated receptors and chemical signals to activate signaling transduction pathways. However, increasing evidence has also indicated that the phospholipid bilayer itself by altering various physical parameters serves as a sensor that regulate membrane proteins in a specific manner. Changes in thickness and/or curvature of the membrane have been shown to be induced by mechanical forces and transmitted through the transmembrane helices of several types of mechanosensitive (MS) ion channels underlying functions such as osmoregulation in bacteria and sensory processing in mammalian cells. This review focus on recent protein functional and structural data indicating that the activation of bacterial and yeast osmosensors is consistent with thickness-induced tilting changes of the transmembrane domains of these proteins. Membrane thinning in combination with curvature changes may also lead to the lateral transfer of the small lipid-anchored GTPases Ras1 and H-Ras out of lipid rafts for clustering and signaling. The modulation of signaling pathways by amphiphilic peptides and the membrane-active antibiotics colistin and Amphotericin B is also discussed.
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Affiliation(s)
- B Eleazar Cohen
- Division of External Activities, National Institute of Allergy and Infectious Diseases, Bethesda, MD, United States
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50
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Marquette A, Bechinger B. Biophysical Investigations Elucidating the Mechanisms of Action of Antimicrobial Peptides and Their Synergism. Biomolecules 2018; 8:E18. [PMID: 29670065 PMCID: PMC6023007 DOI: 10.3390/biom8020018] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 04/13/2018] [Accepted: 04/16/2018] [Indexed: 01/30/2023] Open
Abstract
Biophysical and structural investigations are presented with a focus on the membrane lipid interactions of cationic linear antibiotic peptides such as magainin, PGLa, LL37, and melittin. Observations made with these peptides are distinct as seen from data obtained with the hydrophobic peptide alamethicin. The cationic amphipathic peptides predominantly adopt membrane alignments parallel to the bilayer surface; thus the distribution of polar and non-polar side chains of the amphipathic helices mirror the environmental changes at the membrane interface. Such a membrane partitioning of an amphipathic helix has been shown to cause considerable disruptions in the lipid packing arrangements, transient openings at low peptide concentration, and membrane disintegration at higher peptide-to-lipid ratios. The manifold supramolecular arrangements adopted by lipids and peptides are represented by the 'soft membranes adapt and respond, also transiently' (SMART) model. Whereas molecular dynamics simulations provide atomistic views on lipid membranes in the presence of antimicrobial peptides, the biophysical investigations reveal interesting details on a molecular and supramolecular level, and recent microscopic imaging experiments delineate interesting sequences of events when bacterial cells are exposed to such peptides. Finally, biophysical studies that aim to reveal the mechanisms of synergistic interactions of magainin 2 and PGLa are presented, including unpublished isothermal titration calorimetry (ITC), circular dichroism (CD) and dynamic light scattering (DLS) measurements that suggest that the peptides are involved in liposome agglutination by mediating intermembrane interactions. A number of structural events are presented in schematic models that relate to the antimicrobial and synergistic mechanism of amphipathic peptides when they are aligned parallel to the membrane surface.
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Affiliation(s)
- Arnaud Marquette
- Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, 4, rue Blaise Pascal, 67070 Strasbourg, France.
| | - Burkhard Bechinger
- Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, 4, rue Blaise Pascal, 67070 Strasbourg, France.
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