1
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Bull TJ, Munshi T, Lopez-Perez PM, Tran AC, Cosgrove C, Bartolf A, Menichini M, Rindi L, Parigger L, Malanovic N, Lohner K, Wang CJH, Fatima A, Martin LL, Esin S, Batoni G, Hilpert K. Specific Cationic Antimicrobial Peptides Enhance the Recovery of Low-Load Quiescent Mycobacterium tuberculosis in Routine Diagnostics. Int J Mol Sci 2023; 24:17555. [PMID: 38139385 PMCID: PMC10743970 DOI: 10.3390/ijms242417555] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/07/2023] [Accepted: 12/11/2023] [Indexed: 12/24/2023] Open
Abstract
The culture confirmation of Mycobacterium tuberculosis (MTB) remains the gold standard for the diagnosis of Tuberculosis (TB) with culture conversion representing proof of cure. However, over 40% of TB samples fail to isolate MTB even though many patients remain infectious due to the presence of viable non-culturable forms. Previously, we have shown that two short cationic peptides, T14D and TB08L, induce a hormetic response at low concentrations, leading to a stimulation of growth in MTB and the related animal pathogen Mycobacterium bovis (bTB). Here, we examine these peptides showing they can influence the mycobacterial membrane integrity and function through membrane potential reduction. We also show this disruption is associated with an abnormal reduction in transcriptomic signalling from specific mycobacterial membrane sensors that normally monitor the immediate cellular environment and maintain the non-growing phenotype. We observe that exposing MTB or bTB to these peptides at optimal concentrations rapidly represses signalling mechanisms maintaining dormancy phenotypes, which leads to the promotion of aerobic metabolism and conversion into a replicative phenotype. We further show a practical application of these peptides as reagents able to enhance conventional routine culture methods by stimulating mycobacterial growth. We evaluated the ability of a peptide-supplemented sample preparation and culture protocol to isolate the MTB against a gold standard routine method tested in parallel on 255 samples from 155 patients with suspected TB. The peptide enhancement increased the sample positivity rate by 46% and decreased the average time to sample positivity of respiratory/faecal sampling by seven days. The most significant improvements in isolation rates were from sputum smear-negative low-load samples and faeces. The peptide enhancement increased sampling test sensitivity by 19%, recovery in samples from patients with a previously culture-confirmed TB by 20%, and those empirically treated for TB by 21%. We conclude that sample decontamination and culture enhancement with D-enantiomer peptides offer good potential for the much-needed improvement of the culture confirmation of TB.
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Affiliation(s)
- Tim J. Bull
- Institute of Infection and Immunity, St. George’s, University of London, Cranmer Terrace, London SW17 0RE, UK (K.H.)
| | - Tulika Munshi
- Institute of Infection and Immunity, St. George’s, University of London, Cranmer Terrace, London SW17 0RE, UK (K.H.)
| | | | - Andy C. Tran
- Institute of Infection and Immunity, St. George’s, University of London, Cranmer Terrace, London SW17 0RE, UK (K.H.)
| | - Catherine Cosgrove
- St. George’s Hospital NHS Trust, Cranmer Terrace, London SW17 0RE, UK; (C.C.)
| | - Angela Bartolf
- St. George’s Hospital NHS Trust, Cranmer Terrace, London SW17 0RE, UK; (C.C.)
| | - Melissa Menichini
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy (L.R.); (S.E.); (G.B.)
| | - Laura Rindi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy (L.R.); (S.E.); (G.B.)
| | - Lena Parigger
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Humboldstrasse 50/III, 800 Graz, Austria; (L.P.); (K.L.)
| | - Nermina Malanovic
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Humboldstrasse 50/III, 800 Graz, Austria; (L.P.); (K.L.)
| | - Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Humboldstrasse 50/III, 800 Graz, Austria; (L.P.); (K.L.)
| | - Carl J. H. Wang
- School of Chemistry, Monash University, Clayton, VIC 3800, Australia (A.F.); (L.L.M.)
| | - Anam Fatima
- School of Chemistry, Monash University, Clayton, VIC 3800, Australia (A.F.); (L.L.M.)
| | - Lisandra L. Martin
- School of Chemistry, Monash University, Clayton, VIC 3800, Australia (A.F.); (L.L.M.)
| | - Semih Esin
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy (L.R.); (S.E.); (G.B.)
| | - Giovanna Batoni
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy (L.R.); (S.E.); (G.B.)
| | - Kai Hilpert
- Institute of Infection and Immunity, St. George’s, University of London, Cranmer Terrace, London SW17 0RE, UK (K.H.)
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2
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Jennings J, Ašćerić D, Semeraro EF, Lohner K, Malanovic N, Pabst G. Combinatorial Screening of Cationic Lipidoids Reveals How Molecular Conformation Affects Membrane-Targeting Antimicrobial Activity. ACS Appl Mater Interfaces 2023; 15:40178-40190. [PMID: 37602460 PMCID: PMC10472336 DOI: 10.1021/acsami.3c05481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 08/04/2023] [Indexed: 08/22/2023]
Abstract
The search for next-generation antibacterial compounds that overcome the development of resistance can be facilitated by identifying how to target the cell membrane of bacteria. Understanding the key molecular features that enable interactions with lipids and lead to membrane disruption is therefore crucial. Here, we employ a library of lipid-like compounds (lipidoids) comprising modular structures with tunable hydrophobic and hydrophilic architecture to shed light on how the chemical functionality and molecular shape of synthetic amphiphilic compounds determine their activity against bacterial membranes. Synthesized from combinations of 8 different polyamines as headgroups and 13 acrylates as tails, 104 different lipidoids are tested for activity against a model Gram-positive bacterial strain (Bacillus subtilis). Results from the combinatorial screening assay show that lipidoids with the most potent antimicrobial properties (down to 2 μM) have intermediate tail hydrophobicity (i.e., c log P values between 3 and 4) and lower headgroup charge density (i.e., longer spacers between charged amines). However, the most important factor appeared to be the ability of a lipidoid to self-assemble into an inverse hexagonal liquid crystalline phase, as observed by small-angle X-ray scattering (SAXS) analysis. The lipidoids active at lowest concentrations, which induced the most significant membrane damage during propidium iodide (PI) permeabilization assays, were those that aggregated into highly curved inverse hexagonal liquid crystal phases. These observations suggest that the introduction of strong curvature stress into the membrane is one way to maximize membrane disruption and lipidoid antimicrobial activity. Lipidoids that demonstrated the ability to furnish this phase consisted of either (i) branched or linear headgroups with shorter linear tails or (ii) cyclic headgroups with 4 bulky nonlinear tails. On the contrary, lipidoids previously observed to adopt disc-like conformations that pack into bicontinuous cubic phases were significantly less effective against B. subtilis. The discovery of these structure-property relationships demonstrates that it is not simply a balance of hydrophobic and hydrophilic moieties that govern membrane-active antibacterial activity, but also their intrinsic curvature and collective behavior.
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Affiliation(s)
- James Jennings
- Institute
of Molecular Biosciences, University of
Graz, NAWI Graz, 8010 Graz, Austria
- Field
of Excellence BioHealth, University of Graz, 8010 Graz, Austria
| | - Dunja Ašćerić
- Institute
of Molecular Biosciences, University of
Graz, NAWI Graz, 8010 Graz, Austria
- Field
of Excellence BioHealth, University of Graz, 8010 Graz, Austria
| | - Enrico Federico Semeraro
- Institute
of Molecular Biosciences, University of
Graz, NAWI Graz, 8010 Graz, Austria
- Field
of Excellence BioHealth, University of Graz, 8010 Graz, Austria
| | - Karl Lohner
- Institute
of Molecular Biosciences, University of
Graz, NAWI Graz, 8010 Graz, Austria
- Field
of Excellence BioHealth, University of Graz, 8010 Graz, Austria
| | - Nermina Malanovic
- Institute
of Molecular Biosciences, University of
Graz, NAWI Graz, 8010 Graz, Austria
- Field
of Excellence BioHealth, University of Graz, 8010 Graz, Austria
| | - Georg Pabst
- Institute
of Molecular Biosciences, University of
Graz, NAWI Graz, 8010 Graz, Austria
- Field
of Excellence BioHealth, University of Graz, 8010 Graz, Austria
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3
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Ön A, Vejzovic D, Jennings J, Parigger L, Cordfunke RA, Drijfhout JW, Lohner K, Malanovic N. Bactericidal Activity to Escherichia coli: Different Modes of Action of Two 24-Mer Peptides SAAP-148 and OP-145, Both Derived from Human Cathelicidine LL-37. Antibiotics (Basel) 2023; 12:1163. [PMID: 37508259 PMCID: PMC10376646 DOI: 10.3390/antibiotics12071163] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 07/05/2023] [Accepted: 07/06/2023] [Indexed: 07/30/2023] Open
Abstract
OP-145 and SAAP-148, two 24-mer antimicrobial peptides derived from human cathelicidin LL-37, exhibit killing efficacy against both Gram-positive and Gram-negative bacteria at comparable peptide concentrations. However, when it comes to the killing activity against Escherichia coli, the extent of membrane permeabilization does not align with the observed bactericidal activity. This is the case in living bacteria as well as in model membranes mimicking the E. coli cytoplasmic membrane (CM). In order to understand the killing activity of both peptides on a molecular basis, here we studied their mode of action, employing a combination of microbiological and biophysical techniques including differential scanning calorimetry (DSC), zeta potential measurements, and spectroscopic analyses. Various membrane dyes were utilized to monitor the impact of the peptides on bacterial and model membranes. Our findings unveiled distinct binding patterns of the peptides to the bacterial surface and differential permeabilization of the E. coli CM, depending on the smooth or rough/deep-rough lipopolysaccharide (LPS) phenotypes of E. coli strains. Interestingly, the antimicrobial activity and membrane depolarization were not significantly different in the different LPS phenotypes investigated, suggesting a general mechanism that is independent of LPS. Although the peptides exhibited limited permeabilization of E. coli membranes, DSC studies conducted on a mixture of synthetic phosphatidylglycerol/phosphatidylethanolamine/cardiolipin, which mimics the CM of Gram-negative bacteria, clearly demonstrated disruption of lipid chain packing. From these experiments, we conclude that depolarization of the CM and alterations in lipid packing plays a crucial role in the peptides' bactericidal activity.
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Affiliation(s)
- Ayse Ön
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Djenana Vejzovic
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - James Jennings
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Lena Parigger
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Robert A Cordfunke
- Department of Immunology, Leiden University Medical Center, 2333 Leiden, The Netherlands
| | - Jan Wouter Drijfhout
- Department of Immunology, Leiden University Medical Center, 2333 Leiden, The Netherlands
| | - Karl Lohner
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
- Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria
- BioTechMed Graz, 8010 Graz, Austria
| | - Nermina Malanovic
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
- Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria
- BioTechMed Graz, 8010 Graz, Austria
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4
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Semeraro EF, Pajtinka P, Marx L, Kabelka I, Leber R, Lohner K, Vácha R, Pabst G. Magainin 2 and PGLa in bacterial membrane mimics IV: Membrane curvature and partitioning. Biophys J 2022; 121:4689-4701. [PMID: 36258677 PMCID: PMC9748257 DOI: 10.1016/j.bpj.2022.10.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/10/2022] [Accepted: 10/12/2022] [Indexed: 12/15/2022] Open
Abstract
We previously reported that the synergistically enhanced antimicrobial activity of magainin 2 (MG2a) and PGLa is related to membrane adhesion and fusion. Here, we demonstrate that equimolar mixtures of MG2a and L18W-PGLa induce positive monolayer curvature stress and sense, at the same time, positive mean and Gaussian bilayer curvatures already at low amounts of bound peptide. The combination of both abilities-membrane curvature sensing and inducing-is most likely the base for the synergistically enhanced peptide activity. In addition, our coarse-grained simulations suggest that fusion stalks are promoted by decreasing the free-energy barrier for their formation rather than by stabilizing their shape. We also interrogated peptide partitioning as a function of lipid and peptide concentration using tryptophan fluorescence spectroscopy and peptide-induced leakage of dyes from lipid vesicles. In agreement with a previous report, we find increased membrane partitioning of L18W-PGLa in the presence of MG2a. However, this effect does not prevail to lipid concentrations higher than 1 mM, above which all peptides associate with the lipid bilayers. This implies that synergistic effects of MG2a and L18W-PGLa in previously reported experiments with lipid concentrations >1 mM are due to peptide-induced membrane remodeling and not their specific membrane partitioning.
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Affiliation(s)
- Enrico F Semeraro
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | - Peter Pajtinka
- CEITEC - Central European Institute of Technology, Masaryk University, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic; Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Lisa Marx
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | - Ivo Kabelka
- CEITEC - Central European Institute of Technology, Masaryk University, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Regina Leber
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | - Karl Lohner
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | - Robert Vácha
- CEITEC - Central European Institute of Technology, Masaryk University, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic; Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Brno, Czech Republic.
| | - Georg Pabst
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria.
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5
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Vejzovic D, Piller P, Cordfunke RA, Drijfhout JW, Eisenberg T, Lohner K, Malanovic N. Where Electrostatics Matter: Bacterial Surface Neutralization and Membrane Disruption by Antimicrobial Peptides SAAP-148 and OP-145. Biomolecules 2022; 12:biom12091252. [PMID: 36139091 PMCID: PMC9496175 DOI: 10.3390/biom12091252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/30/2022] [Accepted: 09/04/2022] [Indexed: 11/22/2022] Open
Abstract
The need for alternative treatment of multi-drug-resistant bacteria led to the increased design of antimicrobial peptides (AMPs). AMPs exhibit a broad antimicrobial spectrum without a distinct preference for a specific species. Thus, their mechanism, disruption of fundamental barrier function by permeabilization of the bacterial cytoplasmic membrane is considered to be rather general and less likely related to antimicrobial resistance. Of all physico-chemical properties of AMPs, their positive charge seems to be crucial for their interaction with negatively charged bacterial membranes. Therefore, we elucidate the role of electrostatic interaction on bacterial surface neutralization and on membrane disruption potential of two potent antimicrobial peptides, namely, OP-145 and SAAP-148. Experiments were performed on Escherichia coli, a Gram-negative bacterium, and Enterococcus hirae, a Gram-positive bacterium, as well as on their model membranes. Zeta potential measurements demonstrated that both peptides neutralized the surface charge of E. coli immediately after their exposure, but not of E. hirae. Second, peptides neutralized all model membranes, but failed to efficiently disrupt model membranes mimicking Gram-negative bacteria. This was further confirmed by flow cytometry showing reduced membrane permeability for SAAP-148 and the lack of OP-145 to permeabilize the E. coli membrane. As neutralization of E. coli surface charges was achieved before the cells were killed, we conclude that electrostatic forces are more important for actions on the surface of Gram-negative bacteria than on their cytoplasmic membranes.
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Affiliation(s)
- Djenana Vejzovic
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/III, 8010 Graz, Austria
| | - Paulina Piller
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/III, 8010 Graz, Austria
| | - Robert A. Cordfunke
- Department of Immunology, Leiden University Medical Center, 2300 ZA Leiden, The Netherlands
| | - Jan W. Drijfhout
- Department of Immunology, Leiden University Medical Center, 2300 ZA Leiden, The Netherlands
| | - Tobias Eisenberg
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/III, 8010 Graz, Austria
- Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria
- Bio TechMed Graz, 8010 Graz, Austria
| | - Karl Lohner
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/III, 8010 Graz, Austria
- Department of Immunology, Leiden University Medical Center, 2300 ZA Leiden, The Netherlands
- Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria
| | - Nermina Malanovic
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/III, 8010 Graz, Austria
- Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria
- Bio TechMed Graz, 8010 Graz, Austria
- Correspondence:
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6
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Kabelka I, Georgiev V, Marx L, Pajtinka P, Lohner K, Pabst G, Dimova R, Vácha R. Magainin 2 and PGLa in bacterial membrane mimics III: Membrane fusion and disruption. Biophys J 2022; 121:852-861. [PMID: 35134334 PMCID: PMC8943694 DOI: 10.1016/j.bpj.2021.12.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/27/2021] [Accepted: 12/22/2021] [Indexed: 11/30/2022] Open
Abstract
We previously speculated that the synergistically enhanced antimicrobial activity of Magainin 2 and PGLa is related to membrane adhesion, fusion, and further membrane remodeling. Here we combined computer simulations with time-resolved in vitro fluorescence microscopy, cryoelectron microscopy, and small-angle X-ray scattering to interrogate such morphological and topological changes of vesicles at nanoscopic and microscopic length scales in real time. Coarse-grained simulations revealed formation of an elongated and bent fusion zone between vesicles in the presence of equimolar peptide mixtures. Vesicle adhesion and fusion were observed to occur within a few seconds by cryoelectron microscopy and corroborated by small-angle X-ray scattering measurements. The latter experiments indicated continued and time-extended structural remodeling for individual peptides or chemically linked peptide heterodimers but with different kinetics. Fluorescence microscopy further captured peptide-dependent adhesion, fusion, and occasional bursting of giant unilamellar vesicles a few seconds after peptide addition. The synergistic interactions between the peptides shorten the time response of vesicles and enhance membrane fusogenic and disruption properties of the equimolar mixture compared with the individual peptides.
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Affiliation(s)
- Ivo Kabelka
- CEITEC – Central European Institute of Technology, Masaryk University, Brno, Czech Republic,National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Vasil Georgiev
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, Potsdam, Germany
| | - Lisa Marx
- Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, University of Graz, Graz, Austria,BioTechMed Graz, Graz, Austria
| | - Peter Pajtinka
- CEITEC – Central European Institute of Technology, Masaryk University, Brno, Czech Republic,National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic,Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, University of Graz, Graz, Austria,BioTechMed Graz, Graz, Austria
| | - Georg Pabst
- Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, University of Graz, Graz, Austria,BioTechMed Graz, Graz, Austria
| | - Rumiana Dimova
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, Potsdam, Germany
| | - Robert Vácha
- CEITEC - Central European Institute of Technology, Masaryk University, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic; Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Brno, Czech Republic.
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7
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Semeraro EF, Marx L, Mandl J, Letofsky-Papst I, Mayrhofer C, Frewein MPK, Scott HL, Prévost S, Bergler H, Lohner K, Pabst G. Lactoferricins impair the cytosolic membrane of Escherichia coli within a few seconds and accumulate inside the cell. eLife 2022; 11:72850. [PMID: 35670565 PMCID: PMC9352351 DOI: 10.7554/elife.72850] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 06/06/2022] [Indexed: 12/29/2022] Open
Abstract
We report the real-time response of Escherichia coli to lactoferricin-derived antimicrobial peptides (AMPs) on length scales bridging microscopic cell sizes to nanoscopic lipid packing using millisecond time-resolved synchrotron small-angle X-ray scattering. Coupling a multiscale scattering data analysis to biophysical assays for peptide partitioning revealed that the AMPs rapidly permeabilize the cytosolic membrane within less than 3 s-much faster than previously considered. Final intracellular AMP concentrations of ∼80-100 mM suggest an efficient obstruction of physiologically important processes as the primary cause of bacterial killing. On the other hand, damage of the cell envelope and leakage occurred also at sublethal peptide concentrations, thus emerging as a collateral effect of AMP activity that does not kill the bacteria. This implies that the impairment of the membrane barrier is a necessary but not sufficient condition for microbial killing by lactoferricins. The most efficient AMP studied exceeds others in both speed of permeabilizing membranes and lowest intracellular peptide concentration needed to inhibit bacterial growth.
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Affiliation(s)
- Enrico F Semeraro
- University of Graz, Institute of Molecular Biosciences, NAWI GrazGrazAustria,BioTechMed GrazGrazAustria,Field of Excellence BioHealth – University of GrazGrazAustria
| | - Lisa Marx
- University of Graz, Institute of Molecular Biosciences, NAWI GrazGrazAustria,BioTechMed GrazGrazAustria,Field of Excellence BioHealth – University of GrazGrazAustria
| | - Johannes Mandl
- University of Graz, Institute of Molecular Biosciences, NAWI GrazGrazAustria,BioTechMed GrazGrazAustria,Field of Excellence BioHealth – University of GrazGrazAustria
| | - Ilse Letofsky-Papst
- Institute of Electron Microscopy and Nanoanalysis and Center for Electron Microscopy, Graz University of Technology, NAWI GrazGrazAustria
| | | | - Moritz PK Frewein
- University of Graz, Institute of Molecular Biosciences, NAWI GrazGrazAustria,BioTechMed GrazGrazAustria,Field of Excellence BioHealth – University of GrazGrazAustria,Institut Laue-LangevinGrenobleFrance
| | - Haden L Scott
- Center for Environmental Biotechnology, University of TennesseeKnoxvilleUnited States,Shull Wollan Center, Oak Ridge National LaboratoryOak RidgeUnited States
| | | | - Helmut Bergler
- University of Graz, Institute of Molecular Biosciences, NAWI GrazGrazAustria,BioTechMed GrazGrazAustria,Field of Excellence BioHealth – University of GrazGrazAustria
| | - Karl Lohner
- University of Graz, Institute of Molecular Biosciences, NAWI GrazGrazAustria,BioTechMed GrazGrazAustria,Field of Excellence BioHealth – University of GrazGrazAustria
| | - Georg Pabst
- University of Graz, Institute of Molecular Biosciences, NAWI GrazGrazAustria,BioTechMed GrazGrazAustria,Field of Excellence BioHealth – University of GrazGrazAustria
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8
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Marx L, Frewein MPK, Semeraro EF, Rechberger GN, Lohner K, Porcar L, Pabst G. Antimicrobial peptide activity in asymmetric bacterial membrane mimics. Faraday Discuss 2021; 232:435-447. [PMID: 34532723 PMCID: PMC8704130 DOI: 10.1039/d1fd00039j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 07/21/2021] [Indexed: 11/21/2022]
Abstract
We report on the response of asymmetric lipid membranes composed of palmitoyl oleoyl phosphatidylethanolamine and palmitoyl oleoyl phosphatidylglycerol, to interactions with the frog peptides L18W-PGLa and magainin 2 (MG2a), as well as the lactoferricin derivative LF11-215. In particular we determined the peptide-induced lipid flip-flop, as well as membrane partitioning of L18W-PGLa and LF11-215, and vesicle dye-leakage induced by L18W-PGLa. The ability of L18W-PGLa and MG2a to translocate through the membrane appears to correlate with the observed lipid flip-flop, which occurred at the fastest rate for L18W-PGLa. The higher structural flexibility of LF11-215 in turn allows this peptide to insert into the bilayers without detectable changes of membrane asymmetry. The increased vulnerability of asymmetric membranes to L18W-PGLa in terms of permeability, appears to be a consequence of tension differences between the compositionally distinct leaflets, but not due to increased peptide partitioning.
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Affiliation(s)
- Lisa Marx
- University of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria.
- Field of Excellence BioHealth, University of Graz, Graz, Austria
| | - Moritz P K Frewein
- University of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria.
- Field of Excellence BioHealth, University of Graz, Graz, Austria
- Institut Laue-Langevin, 38043 Grenoble, France
| | - Enrico F Semeraro
- University of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria.
- Field of Excellence BioHealth, University of Graz, Graz, Austria
| | - Gerald N Rechberger
- University of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria.
- Field of Excellence BioHealth, University of Graz, Graz, Austria
| | - Karl Lohner
- University of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria.
- Field of Excellence BioHealth, University of Graz, Graz, Austria
| | | | - Georg Pabst
- University of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria.
- Field of Excellence BioHealth, University of Graz, Graz, Austria
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9
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Schromm AB, Paulowski L, Kaconis Y, Kopp F, Koistinen M, Donoghue A, Keese S, Nehls C, Wernecke J, Garidel P, Sevcsik E, Lohner K, Sanchez-Gomez S, Martinez-de-Tejada G, Brandenburg K, Brameshuber M, Schütz GJ, Andrä J, Gutsmann T. Cathelicidin and PMB neutralize endotoxins by multifactorial mechanisms including LPS interaction and targeting of host cell membranes. Proc Natl Acad Sci U S A 2021; 118:e2101721118. [PMID: 34183393 PMCID: PMC8271772 DOI: 10.1073/pnas.2101721118] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Antimicrobial peptides (AMPs) contribute to an effective protection against infections. The antibacterial function of AMPs depends on their interactions with microbial membranes and lipids, such as lipopolysaccharide (LPS; endotoxin). Hyperinflammation induced by endotoxin is a key factor in bacterial sepsis and many other human diseases. Here, we provide a comprehensive profile of peptide-mediated LPS neutralization by systematic analysis of the effects of a set of AMPs and the peptide antibiotic polymyxin B (PMB) on the physicochemistry of endotoxin, macrophage activation, and lethality in mice. Mechanistic studies revealed that the host defense peptide LL-32 and PMB each reduce LPS-mediated activation also via a direct interaction of the peptides with the host cell. As a biophysical basis, we demonstrate modifications of the structure of cholesterol-rich membrane domains and the association of glycosylphosphatidylinositol (GPI)-anchored proteins. Our discovery of a host cell-directed mechanism of immune control contributes an important aspect in the development and therapeutic use of AMPs.
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Affiliation(s)
- Andra B Schromm
- Division of Immunobiophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany;
| | - Laura Paulowski
- Division of Immunobiophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
| | - Yani Kaconis
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
| | - Franziska Kopp
- Division of Immunobiophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
| | - Max Koistinen
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
| | - Annemarie Donoghue
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
| | - Susanne Keese
- Division of Immunobiophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
| | - Christian Nehls
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
| | - Julia Wernecke
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
- Deutsches Elektronen-Synchrotron, D-22607 Hamburg, Germany
| | - Patrick Garidel
- Biophysikalische Chemie, Martin-Luther-Universität Halle-Wittenberg, D-06108 Halle, Germany
| | - Eva Sevcsik
- Institute of Applied Physics at TU Wien, Vienna 1040, Austria
| | - Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, A-8010 Graz, Austria
- BioTechMed-Graz, A-8010 Graz, Austria
| | - Susana Sanchez-Gomez
- Department of Microbiology and Parasitology, University of Navarra, E-31008 Pamplona, Spain
| | - Guillermo Martinez-de-Tejada
- Department of Microbiology and Parasitology, University of Navarra, E-31008 Pamplona, Spain
- Navarra Institute for Health Research, E-31008 Pamplona, Spain
| | - Klaus Brandenburg
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
| | | | | | - Jörg Andrä
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
- Department of Biotechnology, Faculty of Life Sciences, Hamburg University of Applied Sciences, D-21033 Hamburg, Germany
| | - Thomas Gutsmann
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
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10
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Semeraro EF, Marx L, Mandl J, Frewein MPK, Scott HL, Prévost S, Bergler H, Lohner K, Pabst G. Evolution of the analytical scattering model of live Escherichia coli. J Appl Crystallogr 2021; 54:473-485. [PMID: 33953653 PMCID: PMC8056759 DOI: 10.1107/s1600576721000169] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 01/05/2021] [Indexed: 11/10/2022] Open
Abstract
A previously reported multi-scale model for (ultra-)small-angle X-ray (USAXS/SAXS) and (very) small-angle neutron scattering (VSANS/SANS) of live Escherichia coli was revised on the basis of compositional/metabolomic and ultrastructural constraints. The cellular body is modeled, as previously described, by an ellipsoid with multiple shells. However, scattering originating from flagella was replaced by a term accounting for the oligosaccharide cores of the lipopolysaccharide leaflet of the outer membrane including its cross-term with the cellular body. This was mainly motivated by (U)SAXS experiments showing indistinguishable scattering for bacteria in the presence and absence of flagella or fimbrae. The revised model succeeded in fitting USAXS/SAXS and differently contrasted VSANS/SANS data of E. coli ATCC 25922 over four orders of magnitude in length scale. Specifically, this approach provides detailed insight into structural features of the cellular envelope, including the distance of the inner and outer membranes, as well as the scattering length densities of all bacterial compartments. The model was also successfully applied to E. coli K12, used for the authors' original modeling, as well as for two other E. coli strains. Significant differences were detected between the different strains in terms of bacterial size, intermembrane distance and its positional fluctuations. These findings corroborate the general applicability of the approach outlined here to quantitatively study the effect of bactericidal compounds on ultrastructural features of Gram-negative bacteria without the need to resort to any invasive staining or labeling agents.
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Affiliation(s)
- Enrico F Semeraro
- University of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria.,BioTechMed Graz, 8010 Graz, Austria.,Field of Excellence BioHealth - University of Graz, Graz, Austria
| | - Lisa Marx
- University of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria.,BioTechMed Graz, 8010 Graz, Austria.,Field of Excellence BioHealth - University of Graz, Graz, Austria
| | - Johannes Mandl
- University of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria.,BioTechMed Graz, 8010 Graz, Austria.,Field of Excellence BioHealth - University of Graz, Graz, Austria
| | - Moritz P K Frewein
- University of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria.,BioTechMed Graz, 8010 Graz, Austria.,Field of Excellence BioHealth - University of Graz, Graz, Austria.,Institut Laue-Langevin, 38043 Grenoble, France
| | - Haden L Scott
- University of Tennessee, Center for Environmental Biotechnology, Knoxville, Tennessee, USA
| | | | - Helmut Bergler
- University of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria.,BioTechMed Graz, 8010 Graz, Austria.,Field of Excellence BioHealth - University of Graz, Graz, Austria
| | - Karl Lohner
- University of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria.,BioTechMed Graz, 8010 Graz, Austria.,Field of Excellence BioHealth - University of Graz, Graz, Austria
| | - Georg Pabst
- University of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria.,BioTechMed Graz, 8010 Graz, Austria.,Field of Excellence BioHealth - University of Graz, Graz, Austria
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11
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Marx L, Semeraro EF, Mandl J, Kremser J, Frewein MP, Malanovic N, Lohner K, Pabst G. Bridging the Antimicrobial Activity of Two Lactoferricin Derivatives in E. coli and Lipid-Only Membranes. Front Med Technol 2021; 3:625975. [PMID: 35047906 PMCID: PMC8757871 DOI: 10.3389/fmedt.2021.625975] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 01/19/2021] [Indexed: 11/13/2022] Open
Abstract
We coupled the antimicrobial activity of two well-studied lactoferricin derivatives, LF11-215 and LF11-324, in Escherichia coli and different lipid-only mimics of its cytoplasmic membrane using a common thermodynamic framework for peptide partitioning. In particular, we combined an improved analysis of microdilution assays with ζ-potential measurements, which allowed us to discriminate between the maximum number of surface-adsorbed peptides and peptides fully partitioned into the bacteria. At the same time, we measured the partitioning of the peptides into vesicles composed of phosphatidylethanolamine (PE), phosphatidylgylcerol (PG), and cardiolipin (CL) mixtures using tryptophan fluorescence and determined their membrane activity using a dye leakage assay and small-angle X-ray scattering. We found that the vast majority of LF11-215 and LF11-324 readily enter inner bacterial compartments, whereas only 1-5% remain surface bound. We observed comparable membrane binding of both peptides in membrane mimics containing PE and different molar ratios of PG and CL. The peptides' activity caused a concentration-dependent dye leakage in all studied membrane mimics; however, it also led to the formation of large aggregates, part of which contained collapsed multibilayers with sandwiched peptides in the interstitial space between membranes. This effect was least pronounced in pure PG vesicles, requiring also the highest peptide concentration to induce membrane permeabilization. In PE-containing systems, we additionally observed an effective shielding of the fluorescent dyes from leakage even at highest peptide concentrations, suggesting a coupling of the peptide activity to vesicle fusion, being mediated by the intrinsic lipid curvatures of PE and CL. Our results thus show that LF11-215 and LF11-324 effectively target inner bacterial components, while the stored elastic stress makes membranes more vulnerable to peptide translocation.
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Affiliation(s)
- Lisa Marx
- Department of Biophysics, Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
| | - Enrico F. Semeraro
- Department of Biophysics, Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
| | - Johannes Mandl
- Department of Biophysics, Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
| | - Johannes Kremser
- Department of Biophysics, Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
| | - Moritz P. Frewein
- Department of Biophysics, Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
- Soft Matter Science and Support Group, Institut Laue-Langevin, Grenoble, France
| | - Nermina Malanovic
- Department of Biophysics, Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
| | - Karl Lohner
- Department of Biophysics, Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
| | - Georg Pabst
- Department of Biophysics, Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth—University of Graz, Graz, Austria
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12
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Malanovic N, Ön A, Pabst G, Zellner A, Lohner K. Octenidine: Novel insights into the detailed killing mechanism of Gram-negative bacteria at a cellular and molecular level. Int J Antimicrob Agents 2020; 56:106146. [DOI: 10.1016/j.ijantimicag.2020.106146] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/28/2020] [Accepted: 08/19/2020] [Indexed: 01/30/2023]
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13
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Semeraro EF, Mandl J, Marx L, Narayanan T, Prévost S, Bergler H, Lohner K, Pabst G. Antimicrobial Peptides Impair Bacteria Cell Structures within Seconds. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.1383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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14
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Marx L, Semeraro EF, Pabst G, Lohner K. Peptide Kinetics in Symmetric and Asymmetric Membrane Mimics of Gram-Negative Bacteria. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.1986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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15
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Kabelka I, Pachler M, Prévost S, Letofsky-Papst I, Lohner K, Pabst G, Vácha R. Magainin 2 and PGLa in Bacterial Membrane Mimics II: Membrane Fusion and Sponge Phase Formation. Biophys J 2019; 118:612-623. [PMID: 31952806 DOI: 10.1016/j.bpj.2019.12.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 12/06/2019] [Accepted: 12/16/2019] [Indexed: 12/23/2022] Open
Abstract
We studied the synergistic mechanism of equimolar mixtures of magainin 2 (MG2a) and PGLa in phosphatidylethanolamine/phosphatidylglycerol mimics of Gram-negative cytoplasmic membranes. In a preceding article of this series, we reported on the early onset of parallel heterodimer formation of the two antimicrobial peptides already at low concentrations and the resulting defect formation in the membranes. Here, we focus on the structures of the peptide-lipid aggregates occurring in the synergistic regime at elevated peptide concentrations. Using a combination of calorimetric, scattering, electron microscopic, and in silico techniques, we demonstrate that the two peptides, even if applied individually, transform originally large unilamellar vesicles into multilamellar vesicles with a collapsed interbilayer spacing resulting from peptide-induced adhesion. Interestingly, the adhesion does not lead to a peptide-induced lipid separation of charged and charge-neutral species. In addition to this behavior, equimolar mixtures of MG2a and PGLa formed surface-aligned fibril-like structures, which induced adhesion zones between the membranes and the formation of transient fusion stalks in molecular dynamics simulations and a coexisting sponge phase observed by small-angle x-ray scattering. The previously reported increased leakage of lipid vesicles of identical composition in the presence of MG2a/PGLa mixtures is therefore related to a peptide-induced cross-linking of bilayers.
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Affiliation(s)
- Ivo Kabelka
- CEITEC-Central European Institute of Technology, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Michael Pachler
- Biophysics Division, Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | | | - Ilse Letofsky-Papst
- Institute for Electron Microscopy and Nanoanalysis and Center for Electron Microscopy, Graz University of Technology, Graz, Austria
| | - Karl Lohner
- Biophysics Division, Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | - Georg Pabst
- Biophysics Division, Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | - Robert Vácha
- CEITEC-Central European Institute of Technology, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic; Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Brno, Czech Republic.
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16
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Pachler M, Kabelka I, Appavou MS, Lohner K, Vácha R, Pabst G. Magainin 2 and PGLa in Bacterial Membrane Mimics I: Peptide-Peptide and Lipid-Peptide Interactions. Biophys J 2019; 117:1858-1869. [PMID: 31703802 PMCID: PMC7031808 DOI: 10.1016/j.bpj.2019.10.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 10/08/2019] [Accepted: 10/15/2019] [Indexed: 11/30/2022] Open
Abstract
We addressed the onset of synergistic activity of the two well-studied antimicrobial peptides magainin 2 (MG2a) and PGLa using lipid-only mimics of Gram-negative cytoplasmic membranes. Specifically, we coupled a joint analysis of small-angle x-ray and neutron scattering experiments on fully hydrated lipid vesicles in the presence of MG2a and L18W-PGLa to all-atom and coarse-grained molecular dynamics simulations. In agreement with previous studies, both peptides, as well as their equimolar mixture, were found to remain upon adsorption in a surface-aligned topology and to induce significant membrane perturbation, as evidenced by membrane thinning and hydrocarbon order parameter changes in the vicinity of the inserted peptide. These effects were particularly pronounced for the so-called synergistic mixture of 1:1 (mol/mol) L18W-PGLa/MG2a and cannot be accounted for by a linear combination of the membrane perturbations of two peptides individually. Our data are consistent with the formation of parallel heterodimers at concentrations below a synergistic increase of dye leakage from vesicles. Our simulations further show that the heterodimers interact via salt bridges and hydrophobic forces, which apparently makes them more stable than putatively formed antiparallel L18W-PGLa and MG2a homodimers. Moreover, dimerization of L18W-PGLa and MG2a leads to a relocation of the peptides within the lipid headgroup region as compared to the individual peptides. The early onset of dimerization of L18W-PGLa and MG2a at low peptide concentrations consequently appears to be key to their synergistic dye-releasing activity from lipid vesicles at high concentrations.
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Affiliation(s)
- Michael Pachler
- Biophysics Division, Institute of Molecular Biosciences, University of Graz, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | - Ivo Kabelka
- CEITEC-Central European Institute of Technology, Masaryk University, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Marie-Sousai Appavou
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum, Forschungszentrum Jülich GmbH, Germany
| | - Karl Lohner
- Biophysics Division, Institute of Molecular Biosciences, University of Graz, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | - Robert Vácha
- CEITEC-Central European Institute of Technology, Masaryk University, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic; Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Georg Pabst
- Biophysics Division, Institute of Molecular Biosciences, University of Graz, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria.
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17
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Leber R, Pachler M, Kabelka I, Svoboda I, Enkoller D, Vácha R, Lohner K, Pabst G. Synergism of Antimicrobial Frog Peptides Couples to Membrane Intrinsic Curvature Strain. Biophys J 2019; 114:1945-1954. [PMID: 29694871 PMCID: PMC5937145 DOI: 10.1016/j.bpj.2018.03.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/07/2018] [Accepted: 03/12/2018] [Indexed: 01/11/2023] Open
Abstract
Mixtures of the frog peptides magainin 2 and PGLa are well-known for their pronounced synergistic killing of Gram-negative bacteria. We aimed to gain insight into the underlying biophysical mechanism by interrogating the permeabilizing efficacies of the peptides as a function of stored membrane curvature strain. For Gram-negative bacterial-inner-membrane mimics, synergism was only observed when the anionic bilayers exhibited significant negative intrinsic curvatures imposed by monounsaturated phosphatidylethanolamine. In contrast, the peptides and their mixtures did not exhibit significant activities in charge-neutral mammalian mimics, including those with negative curvature, which is consistent with the requirement of charge-mediated peptide binding to the membrane. Our experimental findings are supported by computer simulations showing a significant decrease of the peptide-insertion free energy in membranes upon shifting intrinsic curvatures toward more positive values. The physiological relevance of our model studies is corroborated by a remarkable agreement with the peptide’s synergistic activity in Escherichia coli. We propose that synergism is related to a lowering of a membrane-curvature-strain-mediated free-energy barrier by PGLa that assists membrane insertion of magainin 2, and not by strict pairwise interactions of the two peptides as suggested previously.
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Affiliation(s)
- Regina Leber
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | - Michael Pachler
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | - Ivo Kabelka
- Central European Institute of Technology, Brno, Czech Republic; Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Irene Svoboda
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | | | - Robert Vácha
- Central European Institute of Technology, Brno, Czech Republic; Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | - Georg Pabst
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria.
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18
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Huber A, Oemer G, Malanovic N, Lohner K, Kovács L, Salvenmoser W, Zschocke J, Keller MA, Marx F. Membrane Sphingolipids Regulate the Fitness and Antifungal Protein Susceptibility of Neurospora crassa. Front Microbiol 2019; 10:605. [PMID: 31031714 PMCID: PMC6471014 DOI: 10.3389/fmicb.2019.00605] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 03/11/2019] [Indexed: 02/06/2023] Open
Abstract
The membrane sphingolipid glucosylceramide (GlcCer) plays an important role in fungal fitness and adaptation to most diverse environments. Moreover, reported differences in the structure of GlcCer between fungi, plants and animals render this pathway a promising target for new generation therapeutics. Our knowledge about the GlcCer biosynthesis in fungi is mainly based on investigations of yeasts, whereas this pathway is less well characterized in molds. We therefore performed a detailed lipidomic profiling of GlcCer species present in Neurospora crassa and comprehensively show that the deletion of genes encoding enzymes involved in GlcCer biosynthesis affects growth, conidiation and stress response in this model fungus. Importantly, our study evidences that differences in the pathway intermediates and their functional role exist between N. crassa and other fungal species. We further investigated the role of GlcCer in the susceptibility of N. crassa toward two small cysteine-rich and cationic antimicrobial proteins (AMPs), PAF and PAFB, which originate from the filamentous ascomycete Penicillium chrysogenum. The interaction of these AMPs with the fungal plasma membrane is crucial for their antifungal toxicity. We found that GlcCer determines the susceptibility of N. crassa toward PAF, but not PAFB. A higher electrostatic affinity of PAFB than PAF to anionic membrane surfaces might explain the difference in their antifungal mode of action.
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Affiliation(s)
- Anna Huber
- Division of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Gregor Oemer
- Division of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Nermina Malanovic
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Graz, Austria
| | - Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Graz, Austria
| | - Laura Kovács
- Division of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Johannes Zschocke
- Division of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Markus A Keller
- Division of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Florentine Marx
- Division of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
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19
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de Breij A, Riool M, Cordfunke RA, Malanovic N, de Boer L, Koning RI, Ravensbergen E, Franken M, van der Heijde T, Boekema BK, Kwakman PHS, Kamp N, El Ghalbzouri A, Lohner K, Zaat SAJ, Drijfhout JW, Nibbering PH. The antimicrobial peptide SAAP-148 combats drug-resistant bacteria and biofilms. Sci Transl Med 2019; 10:10/423/eaan4044. [PMID: 29321257 DOI: 10.1126/scitranslmed.aan4044] [Citation(s) in RCA: 300] [Impact Index Per Article: 60.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 08/18/2017] [Accepted: 11/13/2017] [Indexed: 01/07/2023]
Abstract
Development of novel antimicrobial agents is a top priority in the fight against multidrug-resistant (MDR) and persistent bacteria. We developed a panel of synthetic antimicrobial and antibiofilm peptides (SAAPs) with enhanced antimicrobial activities compared to the parent peptide, human antimicrobial peptide LL-37. Our lead peptide SAAP-148 was more efficient in killing bacteria under physiological conditions in vitro than many known preclinical- and clinical-phase antimicrobial peptides. SAAP-148 killed MDR pathogens without inducing resistance, prevented biofilm formation, and eliminated established biofilms and persister cells. A single 4-hour treatment with hypromellose ointment containing SAAP-148 completely eradicated acute and established, biofilm-associated infections with methicillin-resistant Staphylococcus aureus and MDR Acinetobacter baumannii from wounded ex vivo human skin and murine skin in vivo. Together, these data demonstrate that SAAP-148 is a promising drug candidate in the battle against antibiotic-resistant bacteria that pose a great threat to human health.
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Affiliation(s)
- Anna de Breij
- Department of Infectious Diseases, Leiden University Medical Center, 2300 RC Leiden, Netherlands
| | - Martijn Riool
- Department of Medical Microbiology, Amsterdam Infection and Immunity Institute, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, Netherlands
| | - Robert A Cordfunke
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, 2300 RC Leiden, Netherlands
| | - Nermina Malanovic
- Biophysics Division, Institute of Molecular Biosciences, University of Graz, Naturwissenschaftliche Fakultät (NAWI) Graz, BioTechMed, 8010 Graz, Austria
| | - Leonie de Boer
- Department of Medical Microbiology, Amsterdam Infection and Immunity Institute, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, Netherlands
| | - Roman I Koning
- Department of Molecular Cell Biology, Leiden University Medical Center, 2300 RC Leiden, Netherlands.,Netherlands Center for Electron Nanoscopy, Institute of Biology Leiden, Leiden University, 2300 RA Leiden, Netherlands
| | - Elisabeth Ravensbergen
- Department of Infectious Diseases, Leiden University Medical Center, 2300 RC Leiden, Netherlands
| | - Marnix Franken
- Department of Infectious Diseases, Leiden University Medical Center, 2300 RC Leiden, Netherlands
| | - Tobias van der Heijde
- Department of Infectious Diseases, Leiden University Medical Center, 2300 RC Leiden, Netherlands
| | - Bouke K Boekema
- Association of Dutch Burn Centres, 1942 LT Beverwijk, Netherlands
| | - Paulus H S Kwakman
- Department of Medical Microbiology, Amsterdam Infection and Immunity Institute, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, Netherlands
| | - Niels Kamp
- Animal Research Institute, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, Netherlands
| | | | - Karl Lohner
- Biophysics Division, Institute of Molecular Biosciences, University of Graz, Naturwissenschaftliche Fakultät (NAWI) Graz, BioTechMed, 8010 Graz, Austria
| | - Sebastian A J Zaat
- Department of Medical Microbiology, Amsterdam Infection and Immunity Institute, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, Netherlands
| | - Jan W Drijfhout
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, 2300 RC Leiden, Netherlands
| | - Peter H Nibbering
- Department of Infectious Diseases, Leiden University Medical Center, 2300 RC Leiden, Netherlands.
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Pachler M, Kabelka I, Leber R, Letofsky-Papst I, Lohner K, Vacha R, Pabst G. Synergism of Magainins is Not Coupled to the Formation of a Well-Defined Peptide Pore. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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21
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Wodlej C, Riedl S, Rinner B, Leber R, Drechsler C, Voelker DR, Choi JY, Lohner K, Zweytick D. Interaction of two antitumor peptides with membrane lipids - Influence of phosphatidylserine and cholesterol on specificity for melanoma cells. PLoS One 2019; 14:e0211187. [PMID: 30682171 PMCID: PMC6347193 DOI: 10.1371/journal.pone.0211187] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 01/08/2019] [Indexed: 12/19/2022] Open
Abstract
R-DIM-P-LF11-322 and DIM-LF11-318, derived from the cationic human host defense peptide lactoferricin show antitumor activity against human melanoma. While R-DIM-P-LF11-322 interacts specifically with cancer cells, the non-specific DIM-LF11-318 exhibits as well activity against non-neoplastic cells. Recently we have shown that cancer cells expose the negatively charged lipid phosphatidylserine (PS) in the outer leaflet of the plasma membrane, while non-cancer cells just expose zwitterionic or neutral lipids, such as phosphatidylcholine (PC) or cholesterol. Calorimetric and zeta potential studies with R-DIM-P-LF11-322 and cancer-mimetic liposomes composed of PS, PC and cholesterol indicate that the cancer-specific peptide interacts specifically with PS. Cholesterol, however, reduces the effectiveness of the peptide. The non-specific DIM-LF11-318 interacts with PC and PS. Cholesterol does not affect its interaction. The dependence of activity of R-DIM-P-LF11-322 on the presence of exposed PS was also confirmed in vitro upon PS depletion of the outer leaflet of cancer cells by the enzyme PS-decarboxylase. Further corresponding to model studies, cholesterol depleted melanoma plasma membranes showed increased sensitivity to R-DIM-P-LF11-322, whereas activity of DIM-LF11-318 was unaffected. Microscopic studies using giant unilamellar vesicles and melanoma cells revealed strong changes in lateral distribution and domain formation of lipids upon addition of both peptides. Whereas R-DIM-P-LF11-322 enters the cancer cell specifically via PS and reaches an intracellular organelle, the Golgi, inducing mitochondrial swelling and apoptosis, DIM-LF11-318 kills rapidly and non-specifically by lysis of the plasma membrane. In conclusion, the specific interaction of R-DIM-P-LF11-322 with PS and sensitivity to cholesterol seem to modulate its specificity for cancer membranes.
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Affiliation(s)
- Christina Wodlej
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Sabrina Riedl
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Beate Rinner
- Center for Medical Research, Medical University of Graz, Graz, Austria
| | - Regina Leber
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Carina Drechsler
- BIOSS and Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg i. Br., Germany
| | - Dennis R Voelker
- Department of Medicine, National Jewish Health, Denver CO, United States of America
| | - Jae-Yeon Choi
- Department of Medicine, National Jewish Health, Denver CO, United States of America
| | - Karl Lohner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Dagmar Zweytick
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
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22
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Riedl S, Rinner B, Schaider H, Liegl-Atzwanger B, Meditz K, Preishuber-Pflügl J, Grissenberger S, Lohner K, Zweytick D. In vitro and in vivo cytotoxic activity of human lactoferricin derived antitumor peptide R-DIM-P-LF11-334 on human malignant melanoma. Oncotarget 2017; 8:71817-71832. [PMID: 29069749 PMCID: PMC5641092 DOI: 10.18632/oncotarget.17823] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 04/11/2017] [Indexed: 02/02/2023] Open
Abstract
Di-peptides derived from the human host defense peptide lactoferricin were previously described to specifically interact with the negatively charged lipid phosphatidylserine exposed by cancer cells. In this study one further derivative, namely R-DIM-P-LF11-334 is shown to exhibit even increased cancer toxicity in vitro and in vivo while non-neoplastic cells are not harmed. In liposomal model systems composed of phosphatidylserine mimicking cancerous and phosphatidylcholine mimicking non-cancerous membranes the specific interaction with the cancer marker PS was confirmed by specific induction of membrane perturbation and permeabilization in presence of the peptide. In vitro studies with cell lines of human malignant melanoma, such as A375, or primary cells of human melanoma metastases to the brain, as MUG Mel1, and non-neoplastic human dermal fibroblasts NHDF revealed high cytotoxic effect of R-DIM-P-LF11-334 on melanoma cells of A375 and MUG Mel1, whereas only minor effect on the dermal fibroblasts NHDF was observed, yielding an about 20-fold killing-specificity for A375 and MUG-Mel1. The LC50 values for melanoma A375 and MUG Mel1 were about 10 μM. Analysis of secondary structure of the peptide revealed an increase in the proportion of β-sheets exclusively in presence of the cancer mimic. Stability studies further indicated a potential adequate stability in blood or under stringent conditions. Importantly the cytotoxic effect on cancer cells was also proven in vivo in mouse xenografts of human melanoma, where peptide treatment induced strong tumor regression and in average a tumor area reduction of 85% compared to tumors of control mice without peptide treatment.
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Affiliation(s)
- Sabrina Riedl
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,Institute of Pathology, Medical University of Graz, Graz, Austria
| | | | - Helmut Schaider
- Biomedical Research, Medical University of Graz, Graz, Austria.,Cancer Biology Unit, Department of Dermatology, Medical University of Graz, Graz, Austria
| | - Bernadette Liegl-Atzwanger
- Dermatology Research Centre, The University of Queensland, School of Medicine, Southern Clinical Division, Woolloongabba, Brisbane, Queensland, Australia
| | | | - Julia Preishuber-Pflügl
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Sarah Grissenberger
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Karl Lohner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Dagmar Zweytick
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,Institute of Pathology, Medical University of Graz, Graz, Austria
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23
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Lohner K. Membrane-active Antimicrobial Peptides as Template Structures for Novel Antibiotic Agents. Curr Top Med Chem 2017; 17:508-519. [PMID: 28117020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 03/07/2016] [Accepted: 03/14/2016] [Indexed: 06/06/2023]
Abstract
The increase of pathogens being resistant to antibiotics represents a global health problem and therefore it is a pressing need to develop antibiotics with novel mechanisms of action. Host defense peptides, which have direct antimicrobial activity (also termed antimicrobial peptides) or immune modulating activity, are valuable template structures for the development of such compounds. Antimicrobial peptides exhibit remarkably different structures as well as biological activity profiles with multiple targets. A large fraction of these peptides interfere physically with the cell membrane of bacteria (focus of this review), but can also translocate into the cytosol, where they interact with nucleic acids, ribosomes and proteins. Several potential interaction sites have to be considered on the route of the peptides from the environment to the cytoplasmic membrane. Translocation of peptides through the cell wall may not be impaired by the thick but relatively porous peptidoglycan layer. However, interaction with lipopolysaccharides of the outer membrane of Gram-negative bacteria and (lipo)teichoic acids of Gram-positive bacteria may reduce the effective concentration at the cytoplasmic membrane, where supposedly the killing event takes place. On a molecular level several mechanisms are discussed, which are important for the rational design of improved antimicrobial compounds: toroidal pore formation, carpet model (coverage of membrane surface by peptides), interfacial activity, void formation, clustering of lipids and effects of membrane curvature. In summary, many of these models just represent special cases that can be interrelated to each other and depend on both the nature of lipids and peptides.
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Affiliation(s)
- Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, BioTech- Med Graz, Humboldtstrasse 50/III, 8010 Graz, Austria
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24
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25
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Malanovic N, Lohner K. Antimicrobial Peptides Targeting Gram-Positive Bacteria. Pharmaceuticals (Basel) 2016; 9:E59. [PMID: 27657092 PMCID: PMC5039512 DOI: 10.3390/ph9030059] [Citation(s) in RCA: 217] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/07/2016] [Accepted: 09/13/2016] [Indexed: 01/01/2023] Open
Abstract
Antimicrobial peptides (AMPs) have remarkably different structures as well as biological activity profiles, whereupon most of these peptides are supposed to kill bacteria via membrane damage. In order to understand their molecular mechanism and target cell specificity for Gram-positive bacteria, it is essential to consider the architecture of their cell envelopes. Before AMPs can interact with the cytoplasmic membrane of Gram-positive bacteria, they have to traverse the cell wall composed of wall- and lipoteichoic acids and peptidoglycan. While interaction of AMPs with peptidoglycan might rather facilitate penetration, interaction with anionic teichoic acids may act as either a trap for AMPs or a ladder for a route to the cytoplasmic membrane. Interaction with the cytoplasmic membrane frequently leads to lipid segregation affecting membrane domain organization, which affects membrane permeability, inhibits cell division processes or leads to delocalization of essential peripheral membrane proteins. Further, precursors of cell wall components, especially the highly conserved lipid II, are directly targeted by AMPs. Thereby, the peptides do not inhibit peptidoglycan synthesis via binding to proteins like common antibiotics, but form a complex with the precursor molecule, which in addition can promote pore formation and membrane disruption. Thus, the multifaceted mode of actions will make AMPs superior to antibiotics that act only on one specific target.
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Affiliation(s)
- Nermina Malanovic
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Austria.
| | - Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Austria.
- BioTechMed Graz, Humboldtstrasse 50/III, 8010 Graz, Austria.
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26
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Lohner K. Membrane-active Antimicrobial Peptides as Template Structures for Novel Antibiotic Agents. Curr Top Med Chem 2016:CTMC-EPUB-77046. [PMID: 27411329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 03/07/2016] [Accepted: 03/14/2016] [Indexed: 06/06/2023]
Abstract
The increase of pathogens being resistant to antibiotics represents a global health problem and thus, there is an urgent need for the development of antibiotics with novel mechanisms of action. Host defense peptides, which have direct antimicrobial activity (also termed antimicrobial peptides) or immune modulating activity, are valuable template structures for the development of such compounds. Antimicrobial peptides exhibit remarkably different structures as well as biological activity profiles with multiple targets. A large fraction of these peptides interfere physically with the cell membrane of bacteria (focus of this review), but can also translocate into the cytosol, where they interact with nucleic acids, ribosomes and proteins. Several potential interaction sites have to be considered on the route of the peptides from the environment to the cytoplasmic membrane. Translocation of peptides through the cell wall may not be impaired by the thick but relatively porous peptidoglycan layer. However, interaction with lipopolysaccharides of the outer membrane of Gram-negative bacteria and (lipo)teichoic acids of Gram-positive bacteria may reduce the effective concentration at the cytoplasmic membrane, where supposedly the killing event takes place. On a molecular level several mechanisms are discussed, which are important for the rational design of improved antimicrobial compounds: toroidal pore formation, carpet model (coverage of membrane surface by peptides), interfacial activity, void formation, clustering of lipids and effects of membrane curvature. In summary, many of these models just represent special cases that can be interrelated to each other and depend on the nature of lipids and peptides.
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Affiliation(s)
- Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, BioTechMed Graz, Humboldtstrasse 50/III, 8010 Graz, Austria.
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27
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Affiliation(s)
- Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Austria; BioTechMed-Graz, Austria.
| | - Kai Hilpert
- Institute of Infection and Immunity, St. George's University of London, London, United Kingdom.
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28
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Malanovic N, Lohner K. Gram-positive bacterial cell envelopes: The impact on the activity of antimicrobial peptides. Biochimica et Biophysica Acta (BBA) - Biomembranes 2016; 1858:936-46. [DOI: 10.1016/j.bbamem.2015.11.004] [Citation(s) in RCA: 249] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 11/05/2015] [Accepted: 11/06/2015] [Indexed: 12/21/2022]
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Brandenburg K, Heinbockel L, Correa W, Lohner K. Peptides with dual mode of action: Killing bacteria and preventing endotoxin-induced sepsis. Biochim Biophys Acta 2016; 1858:971-9. [PMID: 26801369 DOI: 10.1016/j.bbamem.2016.01.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 01/13/2016] [Accepted: 01/18/2016] [Indexed: 01/09/2023]
Abstract
Bacterial infections, with the most severe form being sepsis, can often not be treated adequately leading to high morbidity and lethality of infected patients in critical care units. In particular, the increase in resistant bacterial strains and the lack of new antibiotics are main reasons for the worsening of the current situation, As a new approach, the use of antimicrobial peptides (AMPs) seems to be promising, combining the ability of broad-spectrum bactericidal activity and low potential of induction of resistance. Peptides based on natural defense proteins or polypeptides such as lactoferrin, Limulus anti-lipopolysaccharide factor (LALF), cathelicidins, and granulysins are candidates due to their high affinity to bacteria and to their pathogenicity factors, in first line lipopolysaccharide (LPS, endotoxin) of Gram-negative origin. In this review, we discuss literature with the focus on the use of AMPs from natural sources and their variants as antibacterial as well as anti-endotoxin (anti-inflammatory) drugs. Considerable progress has been made by the design of new AMPs for acting efficiently against the LPS-induced inflammation reaction in vitro as well as in vivo (mouse) models of sepsis. Furthermore, the data indicate that efficient antibacterial compounds are not necessarily equally efficient as anti-endotoxin drugs and vice versa. The most important reason for this may be the different molecular geometry of LPS in bacteria and in free form. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert.
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Affiliation(s)
- Klaus Brandenburg
- Forschungszentrum Borstel, Div. of Biophysics, Parkallee 10, D-23845 Borstel, Germany.
| | - Lena Heinbockel
- Clinical and Experimental Pathology, Parkallee 10, D-23845 Borstel, Germany
| | - Wilmar Correa
- Forschungszentrum Borstel, Div. of Biophysics, Parkallee 10, D-23845 Borstel, Germany
| | - Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, BioTechMed Graz, Humboldtstr. 50/III, Graz, Austria
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30
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Riedl S, Leber R, Rinner B, Schaider H, Lohner K, Zweytick D. Human lactoferricin derived di-peptides deploying loop structures induce apoptosis specifically in cancer cells through targeting membranous phosphatidylserine. Biochimica et Biophysica Acta (BBA) - Biomembranes 2015; 1848:2918-31. [DOI: 10.1016/j.bbamem.2015.07.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 07/10/2015] [Accepted: 07/30/2015] [Indexed: 12/22/2022]
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31
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Sánchez-Gómez S, Ferrer-Espada R, Stewart PS, Pitts B, Lohner K, Martínez de Tejada G. Antimicrobial activity of synthetic cationic peptides and lipopeptides derived from human lactoferricin against Pseudomonas aeruginosa planktonic cultures and biofilms. BMC Microbiol 2015; 15:137. [PMID: 26149536 PMCID: PMC4491869 DOI: 10.1186/s12866-015-0473-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 06/26/2015] [Indexed: 12/05/2022] Open
Abstract
Background Infections by Pseudomonas aeruginosa constitute a serious health threat because this pathogen –particularly when it forms biofilms – can acquire resistance to the majority of conventional antibiotics. This study evaluated the antimicrobial activity of synthetic peptides based on LF11, an 11-mer peptide derived from human lactoferricin against P. aeruginosa planktonic and biofilm-forming cells. We included in this analysis selected N-acylated derivatives of the peptides to analyze the effect of acylation in antimicrobial activity. To assess the efficacy of compounds against planktonic bacteria, microdilution assays to determine the minimal inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and time-kill studies were conducted. The anti-biofilm activity of the agents was assessed on biofilms grown under static (on microplates) and dynamic (in a CDC-reactor) flow regimes. Results The antimicrobial activity of lipopeptides differed from that of non-acylated peptides in their killing mechanisms on planktonic and biofilm-forming cells. Thus, acylation enhanced the bactericidal activity of the parental peptides and resulted in lipopeptides that were uniformly bactericidal at their MIC. In contrast, acylation of the most potent anti-biofilm peptides resulted in compounds with lower anti-biofilm activity. Both peptides and lipopeptides displayed very rapid killing kinetics and all of them required less than 21 min to reduce 1,000 times the viability of planktonic cells when tested at 2 times their MBC. The peptides, LF11-215 (FWRIRIRR) and LF11-227 (FWRRFWRR), displayed the most potent anti-biofilm activity causing a 10,000 fold reduction in cell viability after 1 h of treatment at 10 times their MIC. At that concentration, these two compounds exhibited low citotoxicity on human cells. In addition to its bactericidal activity, LF11-227 removed more that 50 % of the biofilm mass in independent assays. Peptide LF11-215 and two of the shortest and least hydrophobic lipopeptides, DI-MB-LF11-322 (2,2-dimethylbutanoyl-PFWRIRIRR) and DI-MB-LF11-215, penetrated deep into the biofilm structure and homogenously killed biofilm-forming bacteria. Conclusion We identified peptides derived from human lactoferricin with potent antimicrobial activity against P. aeruginosa growing either in planktonic or in biofilm mode. Although further structure-activity relationship analyses are necessary to optimize the anti-biofilm activity of these compounds, the results indicate that lactoferricin derived peptides are promising anti-biofilm agents.
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Affiliation(s)
- Susana Sánchez-Gómez
- Department of Microbiology, University of Navarra, Irunlarrea 1, E-31008, Pamplona, Spain. .,Present address: Susana Sánchez-Gómez, Bionanoplus, 31110, Noain, Spain.
| | - Raquel Ferrer-Espada
- Department of Microbiology, University of Navarra, Irunlarrea 1, E-31008, Pamplona, Spain.
| | - Philip S Stewart
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA.
| | - Betsey Pitts
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA.
| | - Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Graz, Austria.
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Rieder A, Koller D, Lohner K, Pabst G. Optimizing rapid solvent exchange preparation of multilamellar vesicles. Chem Phys Lipids 2015; 186:39-44. [DOI: 10.1016/j.chemphyslip.2014.12.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 12/15/2014] [Accepted: 12/16/2014] [Indexed: 11/27/2022]
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33
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Hofbauer HF, Schopf FH, Schleifer H, Knittelfelder OL, Pieber B, Rechberger GN, Wolinski H, Gaspar ML, Kappe CO, Stadlmann J, Mechtler K, Zenz A, Lohner K, Tehlivets O, Henry SA, Kohlwein SD. Regulation of gene expression through a transcriptional repressor that senses acyl-chain length in membrane phospholipids. Dev Cell 2014; 29:729-39. [PMID: 24960695 PMCID: PMC4070385 DOI: 10.1016/j.devcel.2014.04.025] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 04/01/2014] [Accepted: 04/22/2014] [Indexed: 12/20/2022]
Abstract
Membrane phospholipids typically contain fatty acids (FAs) of 16 and 18 carbon atoms. This particular chain length is evolutionarily highly conserved and presumably provides maximum stability and dynamic properties to biological membranes in response to nutritional or environmental cues. Here, we show that the relative proportion of C16 versus C18 FAs is regulated by the activity of acetyl-CoA carboxylase (Acc1), the first and rate-limiting enzyme of FA de novo synthesis. Acc1 activity is attenuated by AMPK/Snf1-dependent phosphorylation, which is required to maintain an appropriate acyl-chain length distribution. Moreover, we find that the transcriptional repressor Opi1 preferentially binds to C16 over C18 phosphatidic acid (PA) species: thus, C16-chain containing PA sequesters Opi1 more effectively to the ER, enabling AMPK/Snf1 control of PA acyl-chain length to determine the degree of derepression of Opi1 target genes. These findings reveal an unexpected regulatory link between the major energy-sensing kinase, membrane lipid composition, and transcription. AMPK/Snf1 inhibition of acetyl-CoA carboxylase controls fatty acyl-chain length Opi1 repressor preferentially binds to C16 rather than C18 acyl-chains in PA Acyl-chain length tunes Opi1 sequestration to the ER and target gene derepression AMPK/Snf1 thus uses its effect on acyl-chain length to control Opi1 target genes
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Affiliation(s)
- Harald F Hofbauer
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria
| | - Florian H Schopf
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria
| | - Hannes Schleifer
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria
| | - Oskar L Knittelfelder
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria
| | - Bartholomäus Pieber
- Institute of Chemistry, University of Graz, Heinrichstrasse 28, 8010 Graz, Austria
| | - Gerald N Rechberger
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria; BioTechMed Graz, 8010 Graz, Austria
| | - Heimo Wolinski
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria; BioTechMed Graz, 8010 Graz, Austria
| | - Maria L Gaspar
- Department of Molecular Biology and Genetics, 249 Biotechnology Building, Cornell University, Ithaca, NY 14853-2703, USA
| | - C Oliver Kappe
- Institute of Chemistry, University of Graz, Heinrichstrasse 28, 8010 Graz, Austria
| | - Johannes Stadlmann
- Protein Chemistry Facility, Institute of Molecular Pathology (IMP), Doktor-Bohr-Gasse 7, 1030 Vienna, Austria
| | - Karl Mechtler
- Protein Chemistry Facility, IMBA Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Doktor-Bohr-Gasse 3, 1030 Vienna, Austria
| | - Alexandra Zenz
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria
| | - Karl Lohner
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria; BioTechMed Graz, 8010 Graz, Austria
| | - Oksana Tehlivets
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria; BioTechMed Graz, 8010 Graz, Austria
| | - Susan A Henry
- Department of Molecular Biology and Genetics, 249 Biotechnology Building, Cornell University, Ithaca, NY 14853-2703, USA
| | - Sepp D Kohlwein
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010 Graz, Austria; BioTechMed Graz, 8010 Graz, Austria.
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34
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Koller D, Lohner K. The role of spontaneous lipid curvature in the interaction of interfacially active peptides with membranes. Biochim Biophys Acta 2014; 1838:2250-9. [PMID: 24853655 DOI: 10.1016/j.bbamem.2014.05.013] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 05/07/2014] [Accepted: 05/08/2014] [Indexed: 01/28/2023]
Abstract
Research on antimicrobial peptides is in part driven by urgent medical needs such as the steady increase in pathogens being resistant to antibiotics. Despite the wealth of information compelling structure-function relationships are still scarce and thus the interfacial activity model has been proposed to bridge this gap. This model also applies to other interfacially active (membrane active) peptides such as cytolytic, cell penetrating or antitumor peptides. One parameter that is strongly linked to interfacial activity is the spontaneous lipid curvature, which is experimentally directly accessible. We discuss different parameters such as H-bonding, electrostatic repulsion, changes in monolayer surface area and lateral pressure that affect induction of membrane curvature, but also vice versa how membrane curvature triggers peptide response. In addition, the impact of membrane lipid composition on the formation of curved membrane structures and its relevance for diverse mode of action of interfacially active peptides and in turn biological activity are described. This article is part of a Special Issue entitled: Interfacially Active Peptides and Proteins. Guest Editors: William C. Wimley and Kalina Hristova.
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Affiliation(s)
- Daniel Koller
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Schmiedlstraße 6, A-8042 Graz, Austria.
| | - Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Schmiedlstraße 6, A-8042 Graz, Austria.
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Riedl S, Rinner B, Schaider H, Lohner K, Zweytick D. Killing of melanoma cells and their metastases by human lactoferricin derivatives requires interaction with the cancer marker phosphatidylserine. Biometals 2014; 27:981-97. [PMID: 24838743 PMCID: PMC4155172 DOI: 10.1007/s10534-014-9749-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 05/05/2014] [Indexed: 01/24/2023]
Abstract
Despite favorable advancements in therapy cancer is still not curative in many cases, which is often due to inadequate specificity for tumor cells. In this study derivatives of a short cationic peptide derived from the human host defense peptide lactoferricin were optimized in their selective toxicity towards cancer cells. We proved that the target of these peptides is the negatively charged membrane lipid phosphatidylserine (PS), specifically exposed on the surface of cancer cells. We have studied the membrane interaction of three peptides namely LF11-322, its N-acyl derivative 6-methyloctanoyl-LF11-322 and its retro repeat derivative R(etro)-DIM-P-LF11-322 with liposomes mimicking cancerous and non-cancerous cell membranes composed of PS and phosphatidylcholine (PC), respectively. Calorimetric and permeability studies showed that N-acylation and even more the repeat derivative of LF11-322 leads to strongly improved interaction with the cancer mimic PS, whereas only the N-acyl derivative also slightly affects PC. Tryptophan fluorescence of selective peptide R-DIM-P-LF11-322 revealed specific peptide penetration into the PS membrane interface and circular dichroism showed change of its secondary structure by increase of proportion of β-sheets just in the presence of the cancer mimic. Data correlated with in vitro studies with cell lines of human melanomas, their metastases and melanocytes, revealing R-DIM-P-LF11-322 to exhibit strongly increased specificity for cancer cells. This indicates the need of high affinity to the target PS, a minimum length and net positive charge, an adequate but moderate hydrophobicity, and capability of adoption of a defined structure exclusively in presence of the target membrane for high antitumor activity.
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Affiliation(s)
- Sabrina Riedl
- Biophysics Division, Institute of Molecular Biosciences, University of Graz, Schmiedlstraße 6, 8042, Graz, Austria
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36
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Abstract
The finding that the antifungal activity of amphotericin B is primarily due to its ability to extract ergosterol from fungal membranes suggests a new rationale for drug design, which should lead to advanced treatments, particularly for invasive fungal infections.
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Affiliation(s)
- Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Graz, Austria
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37
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Zweytick D, Japelj B, Mileykovskaya E, Zorko M, Dowhan W, Blondelle SE, Riedl S, Jerala R, Lohner K. N-acylated peptides derived from human lactoferricin perturb organization of cardiolipin and phosphatidylethanolamine in cell membranes and induce defects in Escherichia coli cell division. PLoS One 2014; 9:e90228. [PMID: 24595074 PMCID: PMC3940911 DOI: 10.1371/journal.pone.0090228] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 01/31/2014] [Indexed: 11/18/2022] Open
Abstract
Two types of recently described antibacterial peptides derived from human lactoferricin, either nonacylated or N-acylated, were studied for their different interaction with membranes of Escherichia coli in vivo and in model systems. Electron microscopy revealed striking effects on the bacterial membrane as both peptide types induced formation of large membrane blebs. Electron and fluorescence microscopy, however demonstrated that only the N-acylated peptides partially induced the generation of oversized cells, which might reflect defects in cell-division. Further a different distribution of cardiolipin domains on the E. coli membrane was shown only in the presence of the N-acylated peptides. The lipid was distributed over the whole bacterial cell surface, whereas cardiolipin in untreated and nonacylated peptide-treated cells was mainly located at the septum and poles. Studies with bacterial membrane mimics, such as cardiolipin or phosphatidylethanolamine revealed that both types of peptides interacted with the negatively charged lipid cardiolipin. The nonacylated peptides however induced segregation of cardiolipin into peptide-enriched and peptide-poor lipid domains, while the N-acylated peptides promoted formation of many small heterogeneous domains. Only N-acylated peptides caused additional severe effects on the main phase transition of liposomes composed of pure phosphatidylethanolamine, while both peptide types inhibited the lamellar to hexagonal phase transition. Lipid mixtures of phosphatidylethanolamine and cardiolipin revealed anionic clustering by all peptide types. However additional strong perturbation of the neutral lipids was only seen with the N-acylated peptides. Nuclear magnetic resonance demonstrated different conformational arrangement of the N-acylated peptide in anionic and zwitterionic micelles revealing possible mechanistic differences in their action on different membrane lipids. We hypothesized that both peptides kill bacteria by interacting with bacterial membrane lipids but only N-acylated peptides interact with both charged cardiolipin and zwitterionic phosphatidylethanolamine resulting in remodeling of the natural phospholipid domains in the E. coli membrane that leads to defects in cell division.
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Affiliation(s)
- Dagmar Zweytick
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Graz, Austria
- * E-mail:
| | - Bostjan Japelj
- Department of Biotechnology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Eugenia Mileykovskaya
- Department of Biochemistry and Molecular Biology, University of Texas Medical School-Houston, Houston, Texas, United States of America
| | - Mateja Zorko
- Department of Biotechnology, National Institute of Chemistry, Ljubljana, Slovenia
| | - William Dowhan
- Department of Biochemistry and Molecular Biology, University of Texas Medical School-Houston, Houston, Texas, United States of America
| | - Sylvie E. Blondelle
- Department of Biochemistry, Torrey Pines Institute for Molecular Studies, San Diego, California, United States of America
| | - Sabrina Riedl
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Graz, Austria
| | - Roman Jerala
- Department of Biotechnology, National Institute of Chemistry, Ljubljana, Slovenia
- Centre of Excellence EN-FIST, Ljubljana, Slovenia
| | - Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Graz, Austria
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Riedl S, Rinner B, Rechberger G, Schaider H, Lohner K, Zweytick D. Interaction of an Antitumor Peptide with Lipids of the Cancer Plasma Membrane - Formation of Membrane Domains and Influence of Cholesterol. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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39
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Malanovic N, Drijfhout JW, Kriechbaum M, Schmuck M, de Breij A, Nibbering P, Lohner K. Point Mutation in the Hydrophobic Region Drives Selectivity and Activity of OP-145, a Derivative of Human Cathelicidin LL-37. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.2487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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40
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Martínez de Tejada G, Sánchez-Gómez S, Rázquin-Olazaran I, Kowalski I, Kaconis Y, Heinbockel L, Andrä J, Schürholz T, Hornef M, Dupont A, Garidel P, Lohner K, Gutsmann T, David SA, Brandenburg K. Bacterial cell wall compounds as promising targets of antimicrobial agents I. Antimicrobial peptides and lipopolyamines. Curr Drug Targets 2012; 13:1121-30. [PMID: 22664072 DOI: 10.2174/138945012802002410] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 09/30/2011] [Accepted: 05/18/2012] [Indexed: 11/22/2022]
Abstract
The first barrier that an antimicrobial agent must overcome when interacting with its target is the microbial cell wall. In the case of Gram-negative bacteria, additional to the cytoplasmic membrane and the peptidoglycan layer, an outer membrane (OM) is the outermost barrier. The OM has an asymmetric distribution of the lipids with phospholipids and lipopolysaccharide (LPS) located in the inner and outer leaflets, respectively. In contrast, Gram-positive bacteria lack OM and possess a much thicker peptidoglycan layer compared to their Gram-negative counterparts. An additional class of amphiphiles exists in Gram-positives, the lipoteichoic acids (LTA), which may represent important structural components. These long molecules cross-bridge the entire cell envelope with their lipid component inserting into the outer leaflet of the cytoplasmic membrane and the teichoic acid portion penetrating into the peptidoglycan layer. Furthermore, both classes of bacteria have other important amphiphiles, such as lipoproteins, whose importance has become evident only recently. It is not known yet whether any of these amphiphilic components are able to stimulate the immune system under physiological conditions as constituents of intact bacteria. However, all of them have a very high pro-inflammatory activity when released from the cell. Such a release may take place through the interaction with the immune system, or with antibiotics (particularly with those targeting cell wall components), or simply by the bacterial division. Therefore, a given antimicrobial agent must ideally have a double character, namely, it must overcome the bacterial cell wall barrier, without inducing the liberation of the pro-inflammatory amphiphiles. Here, new data are presented which describe the development and use of membrane-active antimicrobial agents, in particular antimicrobial peptides (AMPs) and lipopolyamines. In this way, essential progress was achieved, in particular with respect to the inhibition of deleterious consequences of bacterial infections such as severe sepsis and septic shock.
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41
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Pabst G, Prassl R, Amenitsch H, Rappolt M, Lohner K. Scattering techniques in biology--Marking the contributions to the field from Peter Laggner on the occasion of his 68th birthday. Eur Biophys J 2012; 41:777-929. [PMID: 23015062 DOI: 10.1007/s00249-012-0853-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 08/29/2012] [Indexed: 06/01/2023]
Affiliation(s)
- Georg Pabst
- Institute of Biophysics and Nanosystems Research, 8042, Graz, Austria.
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42
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Spanova M, Zweytick D, Lohner K, Klug L, Leitner E, Hermetter A, Daum G. Influence of squalene on lipid particle/droplet and membrane organization in the yeast Saccharomyces cerevisiae. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:647-53. [PMID: 22342273 PMCID: PMC3790963 DOI: 10.1016/j.bbalip.2012.01.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 01/12/2012] [Accepted: 01/30/2012] [Indexed: 02/02/2023]
Abstract
In a previous study (Spanova et al., 2010, J. Biol. Chem., 285, 6127–6133) we demonstrated that squalene, an intermediate of sterol biosynthesis, accumulates in yeast strains bearing a deletion of the HEM1 gene. In such strains, the vast majority of squalene is stored in lipid particles/droplets together with triacylglycerols and steryl esters. In mutants lacking the ability to form lipid particles, however, substantial amounts of squalene accumulate in organelle membranes. In the present study, we investigated the effect of squalene on biophysical properties of lipid particles and biological membranes and compared these results to artificial membranes. Our experiments showed that squalene together with triacylglycerols forms the fluid core of lipid particles surrounded by only a few steryl ester shells which transform into a fluid phase below growth temperature. In the hem1∆ deletion mutant a slight disordering effect on steryl esters was observed indicated by loss of the high temperature transition. Also in biological membranes from the hem1∆ mutant strain the effect of squalene per se is difficult to pinpoint because multiple effects such as levels of sterols and unsaturated fatty acids contribute to physical membrane properties. Fluorescence spectroscopic studies using endoplasmic reticulum, plasma membrane and artificial membranes revealed that it is not the absolute squalene level in membranes but rather the squalene to sterol ratio which mainly affects membrane fluidity/rigidity. In a fluid membrane environment squalene induces rigidity of the membrane, whereas in rigid membranes there is almost no additive effect of squalene. In summary, our results demonstrate that squalene (i) can be well accommodated in yeast lipid particles and organelle membranes without causing deleterious effects; and (ii) although not being a typical membrane lipid may be regarded as a mild modulator of biophysical membrane properties.
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Affiliation(s)
- Miroslava Spanova
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Dagmar Zweytick
- Institute of Biophysics and Nanosystems Research, Austrian Academy of Sciences, Graz, Austria
| | - Karl Lohner
- Institute of Biophysics and Nanosystems Research, Austrian Academy of Sciences, Graz, Austria
| | - Lisa Klug
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Erich Leitner
- Institute of Analytical Chemistry and Food Technology, Graz University of Technology, Austria
| | - Albin Hermetter
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Günther Daum
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
- Corresponding author at: Institute of Biochemistry, Graz University of Technology, Petersgasse 12/II, A-8010 Graz, Austria. Tel.: + 43 316 873 6462; fax: + 43 316 873 6952.
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43
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Broekman DC, Zenz A, Gudmundsdottir BK, Lohner K, Maier VH, Gudmundsson GH. Functional characterization of codCath, the mature cathelicidin antimicrobial peptide from Atlantic cod (Gadus morhua). Peptides 2011; 32:2044-51. [PMID: 21945422 DOI: 10.1016/j.peptides.2011.09.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 09/09/2011] [Accepted: 09/10/2011] [Indexed: 10/17/2022]
Abstract
Cathelicidins are among the best characterized antimicrobial peptides and have been shown to have an important role in mammalian innate immunity. We recently isolated a novel mature cathelicidin peptide (codCath) from Atlantic cod and in the present study we functionally characterized codCath. The peptide demonstrated salt sensitivity with abrogation of activity at physiological salt concentrations. In low ionic strength medium we found activity against marine and non-marine Gram-negative bacteria with an average MIC of 10 μM, weak activity against a Gram-positive bacterium (MIC 80 μM), and pronounced antifungal activity (MIC 2.5 μM). The results suggest the kinetics and mode of action of codCath to be fast killing accompanied by pronounced cell lysis. Extracellular products (ECPs) of three marine bacteria caused breakdown of the peptide into smaller fragments and the cleaved peptide lost its antibacterial activity. Proteolysis of the peptide on the other hand was abolished by prior heat-treatment of the ECPs, suggesting a protease involvement. We observed no cytotoxicity of the peptide in fish cells up to a concentration of 40 μM and the selectivity of activity was confirmed with bacterial and mammalian membrane mimetics. We conclude that the potent broad-spectrum activity of codCath hints at a role of the peptide in cod immune defense.
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44
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Riedl S, Zweytick D, Lohner K. Membrane-active host defense peptides--challenges and perspectives for the development of novel anticancer drugs. Chem Phys Lipids 2011; 164:766-81. [PMID: 21945565 PMCID: PMC3220766 DOI: 10.1016/j.chemphyslip.2011.09.004] [Citation(s) in RCA: 294] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 09/07/2011] [Accepted: 09/08/2011] [Indexed: 12/22/2022]
Abstract
Although much progress has been achieved in the development of cancer therapies in recent decades, problems continue to arise particularly with respect to chemotherapy due to resistance to and low specificity of currently available drugs. Host defense peptides as effector molecules of innate immunity represent a novel strategy for the development of alternative anticancer drug molecules. These cationic amphipathic peptides are able to discriminate between neoplastic and non-neoplastic cells interacting specifically with negatively charged membrane components such as phosphatidylserine (PS), sialic acid or heparan sulfate, which differ between cancer and non-cancer cells. Furthermore, an increased number of microvilli has been found on cancer cells leading to an increase in cell surface area, which may in turn enhance their susceptibility to anticancer peptides. Thus, part of this review will be devoted to the differences in membrane composition of non-cancer and cancer cells with a focus on the exposure of PS on the outer membrane. Normally, surface exposed PS triggers apoptosis, which can however be circumvented by cancer cells by various means. Host defense peptides, which selectively target differences between cancer and non-cancer cell membranes, have excellent tumor tissue penetration and can thus reach the site of both primary tumor and distant metastasis. Since these molecules kill their target cells rapidly and mainly by perturbing the integrity of the plasma membrane, resistance is less likely to occur. Hence, a chapter will also describe studies related to the molecular mechanisms of membrane damage as well as alternative non-membrane related mechanisms. In vivo studies have demonstrated that host defense peptides display anticancer activity against a number of cancers such as e.g. leukemia, prostate, ascite and ovarian tumors, yet so far none of these peptides has made it on the market. Nevertheless, optimization of host defense peptides using various strategies to enhance further selectivity and serum stability is expected to yield novel anticancer drugs with improved properties in respect of cancer cell toxicity as well as reduced development of drug resistance.
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Affiliation(s)
- Sabrina Riedl
- Institute of Biophysics and Nanosystems Research, Austrian Academy of Sciences, Schmiedlstrasse 6, Graz, Austria
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Weghuber J, Aichinger MC, Brameshuber M, Wieser S, Ruprecht V, Plochberger B, Madl J, Horner A, Reipert S, Lohner K, Henics T, Schütz GJ. Cationic amphipathic peptides accumulate sialylated proteins and lipids in the plasma membrane of eukaryotic host cells. Biochim Biophys Acta 2011; 1808:2581-90. [PMID: 21718688 PMCID: PMC3161180 DOI: 10.1016/j.bbamem.2011.06.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 06/08/2011] [Accepted: 06/13/2011] [Indexed: 11/25/2022]
Abstract
Cationic antimicrobial peptides (CAMPs) selectively target bacterial membranes by electrostatic interactions with negatively charged lipids. It turned out that for inhibition of microbial growth a high CAMP membrane concentration is required, which can be realized by the incorporation of hydrophobic groups within the peptide. Increasing hydrophobicity, however, reduces the CAMP selectivity for bacterial over eukaryotic host membranes, thereby causing the risk of detrimental side-effects. In this study we addressed how cationic amphipathic peptides—in particular a CAMP with Lysine–Leucine–Lysine repeats (termed KLK)—affect the localization and dynamics of molecules in eukaryotic membranes. We found KLK to selectively inhibit the endocytosis of a subgroup of membrane proteins and lipids by electrostatically interacting with negatively charged sialic acid moieties. Ultrastructural characterization revealed the formation of membrane invaginations representing fission or fusion intermediates, in which the sialylated proteins and lipids were immobilized. Experiments on structurally different cationic amphipathic peptides (KLK, 6-MO-LF11-322 and NK14-2) indicated a cooperation of electrostatic and hydrophobic forces that selectively arrest sialylated membrane constituents.
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Affiliation(s)
- Julian Weghuber
- Biophysics Institute, Johannes Kepler University Linz, Altenbergerstr 69, A-4040 Linz, Austria.
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Zweytick D, Deutsch G, Andrä J, Blondelle SE, Vollmer E, Jerala R, Lohner K. Studies on lactoferricin-derived Escherichia coli membrane-active peptides reveal differences in the mechanism of N-acylated versus nonacylated peptides. J Biol Chem 2011; 286:21266-76. [PMID: 21515687 DOI: 10.1074/jbc.m110.195412] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To improve the low antimicrobial activity of LF11, an 11-mer peptide derived from human lactoferricin, mutant sequences were designed based on the defined structure of LF11 in the lipidic environment. Thus, deletion of noncharged polar residues and strengthening of the hydrophobic N-terminal part upon adding a bulky hydrophobic amino acid or N-acylation resulted in enhanced antimicrobial activity against Escherichia coli, which correlated with the peptides' degree of perturbation of bacterial membrane mimics. Nonacylated and N-acylated peptides exhibited different effects at a molecular level. Nonacylated peptides induced segregation of peptide-enriched and peptide-poor lipid domains in negatively charged bilayers, although N-acylated peptides formed small heterogeneous domains resulting in a higher degree of packing defects. Additionally, only N-acylated peptides perturbed the lateral packing of neutral lipids and exhibited increased permeability of E. coli lipid vesicles. The latter did not correlate with the extent of improvement of the antimicrobial activity, which could be explained by the fact that elevated binding of N-acylated peptides to lipopolysaccharides of the outer membrane of gram-negative bacteria seems to counteract the elevated membrane permeabilization, reflected in the respective minimal inhibitory concentration for E. coli. The antimicrobial activity of the peptides correlated with an increase of membrane curvature stress and hence bilayer instability. Transmission electron microscopy revealed that only the N-acylated peptides induced tubular protrusions from the outer membrane, whereas all peptides caused detachment of the outer and inner membrane of E. coli bacteria. Viability tests demonstrated that these bacteria were dead before onset of visible cell lysis.
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Affiliation(s)
- Dagmar Zweytick
- Institute of Biophysics and Nanosystems Research, Austrian Academy of Sciences, Schmiedlstrasse 6, A-8042 Graz, Austria
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47
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Abstract
In the skin of fire-bellied toads (Bombina species), an aminoacyl-l/d-isomerase activity is present which catalyses the post-translational isomerization of the l- to the d-form of the second residue of its substrate peptides. Previously, this new type of enzyme was studied in some detail and genes potentially coding for similar polypeptides were found to exist in several vertebrate species including man. Here, we present our studies to the substrate specificity of this isomerase using fluorescence-labeled variants of the natural substrate bombinin H with different amino acids at positions 1, 2 or 3. Surprisingly, this enzyme has a rather low selectivity for residues at position 2 where the change of chirality at the alpha-carbon takes place. In contrast, a hydrophobic amino acid at position 1 and a small one at position 3 of the substrate are essential. Interestingly, some peptides containing a Phe at position 3 also were substrates. Furthermore, we investigated the role of the amino-terminus for substrate recognition. In view of the rather broad specificity of the frog isomerase, we made a databank search for potential substrates of such an enzyme. Indeed, numerous peptides of amphibia and mammals were found which fulfill the requirements determined in this study. Expression of isomerases with similar characteristics in other species can therefore be expected to catalyze the formation of peptides containing d-amino acids.
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Affiliation(s)
- Alexander Jilek
- Institute of Organic Chemistry, Johannes Kepler University Linz, Altenberger Str. 69, 4040, Linz, Austria.
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48
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Blondelle SE, Lohner K. Optimization and high-throughput screening of antimicrobial peptides. Curr Pharm Des 2011; 16:3204-11. [PMID: 20687884 DOI: 10.2174/138161210793292438] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Accepted: 07/21/2010] [Indexed: 11/22/2022]
Abstract
While a well-established process for lead compound discovery in for-profit companies, high-throughput screening is becoming more popular in basic and applied research settings in academia. The development of combinatorial libraries combined with easy and less expensive access to new technologies have greatly contributed to the implementation of high-throughput screening in academic laboratories. While such techniques were earlier applied to simple assays involving single targets or based on binding affinity, they have now been extended to more complex systems such as whole cell-based assays. In particular, the urgent need for new antimicrobial compounds that would overcome the rapid rise of drug-resistant microorganisms, where multiple target assays or cell-based assays are often required, has forced scientists to focus onto high-throughput technologies. Based on their existence in natural host defense systems and their different mode of action relative to commercial antibiotics, antimicrobial peptides represent a new hope in discovering novel antibiotics against multi-resistant bacteria. The ease of generating peptide libraries in different formats has allowed a rapid adaptation of high-throughput assays to the search for novel antimicrobial peptides. Similarly, the availability nowadays of high-quantity and high-quality antimicrobial peptide data has permitted the development of predictive algorithms to facilitate the optimization process. This review summarizes the various library formats that lead to de novo antimicrobial peptide sequences as well as the latest structural knowledge and optimization processes aimed at improving the peptides selectivity.
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Affiliation(s)
- Sylvie E Blondelle
- Membrane Sciences, 3550 General Atomics Court, San Diego, CA 92121, USA.
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49
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Schrems A, Ces O, Larisch VD, Dutter K, Friedmann J, Küpcü S, Stanetty C, Kibrom A, Lohner K, Sleytr UB, Schuster B. Generation of S-Layer Supported Functionalized Lipid Bilayers. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.2955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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50
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Prossnigg F, Hickel A, Pabst G, Lohner K. Packing behaviour of two predominant anionic phospholipids of bacterial cytoplasmic membranes. Biophys Chem 2010; 150:129-35. [PMID: 20451316 PMCID: PMC2905515 DOI: 10.1016/j.bpc.2010.04.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 04/07/2010] [Accepted: 04/08/2010] [Indexed: 11/08/2022]
Abstract
Phosphatidylglycerol and cardiolipin represent the most abundant anionic phospholipid components of cytoplasmic bacterial membranes and thus are used as constituents for membrane mimetic systems. In this study, we have characterized the temperature dependent phase behaviour of the binary system dipalmitoyl-phosphatidylglycerol (DPPG) and tetramyristoyl-cardiolipin (TMCL) using microcalorimetry and X-ray scattering techniques. Both lipids exhibited a very similar main transition temperature (∼ 41 °C), showing a minimum (39.4 °C) for the binary mixtures at XDPPG = 0.8, and exhibited low-temperature phase transitions, which were abolished by incorporation of small amounts (≤ 10 mol%) of the other lipid component. Therefore, over a wide temperature and composition range a lamellar Lβ gel phase is the predominant structure below the chain melting transition, characterized by a relatively broad wide-angle peak for XDPPG ≤ 0.8. This observation suggests the existence of packing inconsistencies of the TMCL/DPPG hydrocarbon lattices in the gel phase, supported by the small average size of lipid clusters (∼ 50 lipids) within this composition range. The bilayer thickness for the lamellar-gel phase showed a monotonic increase (56 Å for TMCL to about 58 Å for XDPPG = 0.8 at 30 °C), which may be explained by different degrees of partial interdigitation of the acyl chains to compensate for the differences in the hydrocarbon lengths of DPPG and TMCL in the Lβ phase.
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Affiliation(s)
- Florian Prossnigg
- Institute of Biophysics and Nanosystems Research, Austrian Academy of Sciences, Schmiedlstrasse 6, A-8042 Graz, Austria
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