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Eckhardt D, Semeraro EF, Steigenberger J, Schnur J, Kalie L, Massing U, Pabst G, Heerklotz H. Eutectic Resolves Lysolipid Paradox in Thermoresponsive Liposomes. Mol Pharm 2024; 21:1768-1776. [PMID: 38381374 DOI: 10.1021/acs.molpharmaceut.3c01094] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
A better molecular understanding of the temperature-triggered drug release from lysolipid-based thermosensitive liposomes (LTSLs) is needed to overcome the recent setbacks in developing this important drug delivery system. Enhanced drug release was previously rationalized in terms of detergent-like effects of the lysolipid monostearyl lysophosphatidylcholine (MSPC), stabilizing local membrane defects upon LTSL lipid melting. This is highly surprising and here referred to as the 'lysolipid paradox,' because detergents usually induce the opposite effect─they cause leakage upon freezing, not melting. Here, we aim at better answers to (i) why lysolipid does not compromise drug retention upon storage of LTSLs in the gel phase, (ii) how lysolipids can enhance drug release from LTSLs upon lipid melting, and (iii) why LTSLs typically anneal after some time so that not all drug gets released. To this end, we studied the phase transitions of mixtures of dipalmitoylphosphatidylcholine (DPPC) and MSPC by a combination of differential scanning and pressure perturbation calorimetry and identified the phase structures with small- and wide-angle X-ray scattering (SAXS and WAXS). The key result is that LTSLs, which contain the standard amount of 10 mol % MSPC, are at a eutectic point when they release their cargo upon melting at about 41 °C. The eutectic present below 41 °C consists of a MSPC-depleted gel phase as well as small domains of a hydrocarbon chain interdigitated gel phase containing some 30 mol % MSPC. In these interdigitated domains, the lysolipid is stored safely without compromising membrane integrity. At the eutectic temperature, both the MSPC-depleted bilayer and interdigitated MSPC-rich domains melt at once to fluid bilayers, respectively. Intact, fluid membranes tolerate much less MSPC than interdigitated domains─where the latter have melted, the high local MSPC content causes transient pores. These pores allow for fast drug release. However, these pores disappear, and the membrane seals again as the MSPC distributes more evenly over the membrane so that its local concentration decreases below the pore-stabilizing threshold. We provide a pseudobinary phase diagram of the DPPC-MSPC system and structural and volumetric data for the interdigitated phase.
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Affiliation(s)
- Daniel Eckhardt
- Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg D79104, Germany
| | - Enrico F Semeraro
- Biophysics, Institute of Molecular Bioscience (IMB), NAWI Graz, University of Graz, Graz 8010, Austria
- Field of Excellence BioHealth, University of Graz, Graz 8010, Austria
| | - Jessica Steigenberger
- Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg D79104, Germany
| | - Johannes Schnur
- Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg D79104, Germany
| | - Louma Kalie
- Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg D79104, Germany
| | - Ulrich Massing
- Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg D79104, Germany
| | - Georg Pabst
- Biophysics, Institute of Molecular Bioscience (IMB), NAWI Graz, University of Graz, Graz 8010, Austria
- Field of Excellence BioHealth, University of Graz, Graz 8010, Austria
| | - Heiko Heerklotz
- Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg D79104, Germany
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
- BIOSS Signaling Research Center, Freiburg D79104, Germany
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Steigenberger J, Verleysen Y, Geudens N, Madder A, Martins JC, Heerklotz H. Complex electrostatic effects on the selectivity of membrane-permeabilizing cyclic lipopeptides. Biophys J 2023; 122:950-963. [PMID: 35927958 PMCID: PMC10111218 DOI: 10.1016/j.bpj.2022.07.033] [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: 03/20/2022] [Revised: 05/04/2022] [Accepted: 07/28/2022] [Indexed: 11/28/2022] Open
Abstract
Cyclic lipopeptides (CLiPs) have many biological functions, including the selective permeabilization of target membranes, and technical and medical applications. We studied the anionic CLiP viscosin from Pseudomonas along with a neutral analog, pseudodesmin A, and the cationic viscosin-E2K to better understand electrostatic effects on target selectivity. Calcein leakage from liposomes of anionic phosphatidylglycerol (PG) and phosphatidylethanolamine (PE) is measured in comparison with net-neutral phosphatidylcholine by time-resolved fluorescence. By contrast to the typical selectivity of cationic peptides against anionic membranes, we find viscosin more active against PG/PE at 30 μM lipid than viscosin-E2K. At very low lipid concentration, the selectivity is reversed. An equi-activity analysis reveals the reciprocal partition coefficients, 1/K, and the CLiP-to-lipid mole ratio within the membrane as leakage after 1 h reaches 50%, Re50. As expected, 1/K to PG/PE is much lower (higher affinity) for viscosin-E2K (3 μM) than viscosin (15 μM). However, the local damage to the PG/PE membrane caused by a viscosin molecule is much stronger than that of viscosin-E2K. This can be explained by the strong membrane expansion due to PG/viscosin repulsion inducing asymmetry stress between the two leaflets and, ultimately, transient limited leakage at Re50 = 0.08. PG/viscosin-E2K attraction opposes expansion and leakage starts only as the PG charges in the outer leaflet are essentially compensated by the cationic peptide (Re50 = 0.32). In the high-lipid regime (at lipid concentrations cL ≫ 1/K), virtually all CLiP is membrane bound anyway and Re50 governs selectivity, favoring viscosin. In the low-lipid regime at cL ≪ 1/K, virtually all CLiP is in solution, 1/K becomes important and the "cation attacks anionic membrane" selectivity gets restored. Overall, activity and selectivity data can only properly be interpreted if the lipid regime is known and predictions for other lipid concentrations or cell counts require knowledge of 1/K and Re50.
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Affiliation(s)
- Jessica Steigenberger
- Department of Pharmaceutics, Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg, Germany.
| | - Yentl Verleysen
- NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium; Organic and Biomimetic Chemistry Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Niels Geudens
- NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Annemieke Madder
- Organic and Biomimetic Chemistry Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - José C Martins
- NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Heiko Heerklotz
- Department of Pharmaceutics, Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg, Germany; Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada; Signaling Research Centers BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.
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Steigenberger J, Mergen C, De Roo V, Geudens N, Martins JC, Heerklotz H. The effect of membrane thickness on the membrane permeabilizing activity of the cyclic lipopeptide tolaasin II. Front Mol Biosci 2022; 9:1064742. [PMID: 36619163 PMCID: PMC9817028 DOI: 10.3389/fmolb.2022.1064742] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 11/21/2022] [Indexed: 12/25/2022] Open
Abstract
Tolaasin II is an amphiphilic, membrane-active, cyclic lipopeptide produced by Pseudomonas tolaasii and is responsible for brown blotch disease in mushroom. To better understand the mode of action and membrane selectivity of tolaasin II and related lipopeptides, its permeabilizing effect on liposomes of different membrane thickness was characterized. An equi-activity analysis served to distinguish between the effects of membrane partitioning and the intrinsic activity of the membrane-bound peptide. It was found that thicker membranes require higher local peptide concentrations to become leaky. More specifically, the mole ratio of membrane-bound peptide per lipid needed to induce 50% leakage of calcein within 1 h, Re 50, increased monotonically with membrane thickness from 0.0016 for the 14:1 to 0.0070 for the 20:1 lipid-chains. Moreover, fast but limited leakage kinetics in the low-lipid regime were observed implying a mode of action based on membrane asymmetry stress in this time and concentration window. While the assembly of the peptide to oligomeric pores of defined length along the bilayer z-axis can in principle explain inhibition by increasing membrane thickness, it cannot account for the observed limited leakage. Therefore, reduced intrinsic membrane-permeabilizing activity with increasing membrane thickness is attributed here to the increased mechanical strength and order of thicker membranes.
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Affiliation(s)
- Jessica Steigenberger
- Department of Pharmaceutics, Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg, Germany,*Correspondence: Jessica Steigenberger, ; Heiko Heerklotz,
| | - Catherine Mergen
- Department of Pharmaceutics, Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg, Germany
| | - Vic De Roo
- NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Niels Geudens
- NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - José C. Martins
- NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Heiko Heerklotz
- Department of Pharmaceutics, Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg, Germany,Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada,Signaling Research Centers BIOSS and CIBSS, University of Freiburg, Freiburg, Germany,*Correspondence: Jessica Steigenberger, ; Heiko Heerklotz,
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Steigenberger J, Verleysen Y, Geudens N, De Roo V, Martins JC, Heerklotz H. Structure-function relationships of membrane permeabilizing cyclic lipopeptides: be prepared for surprises. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.1645] [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: 11/30/2022] Open
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Steigenberger J, Verleysen Y, Geudens N, Martins JC, Heerklotz H. The Optimal Lipid Chain Length of a Membrane-Permeabilizing Lipopeptide Results From the Balance of Membrane Partitioning and Local Damage. Front Microbiol 2021; 12:669709. [PMID: 34594308 PMCID: PMC8476953 DOI: 10.3389/fmicb.2021.669709] [Citation(s) in RCA: 3] [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: 02/19/2021] [Accepted: 08/20/2021] [Indexed: 11/13/2022] Open
Abstract
Pseudodesmin A (PSD) is a cyclic lipodepsipeptide produced by Pseudomonas that kills certain bacteria at MIC1/2 in the single micromolar range, probably by permeabilizing their cellular membranes. Synthetic PSD variants, where the native decanoic (C10) acyl chain is varied in length from C4 to C8 and C12 to C14 carbons, were described to be not or less active against a panel of gram-positive strains, as compared to native PSD-C10. Here, we test the membrane-permeabilizing activity of PSD-C4 through PSD-C14 in terms of calcein release from liposomes, which is characterized in detail by the fluorescence-lifetime based leakage assay. Antagonistic concentrations and their chain length dependence agree well for liposome leakage and antimicrobial activity. The optimal chain length is governed by a balance between membrane partitioning (favoring longer chains) and the local perturbation or “damage” inflicted by a membrane-bound molecule (weakening for longer chains). Local perturbation, in turn, may involve at least two modes of action. Asymmetry stress between outer and inner leaflet builds up as the lipopeptides enter the outer leaflet and when it reaches a system-specific stability threshold, it causes a transient membrane failure that allows for the flip of some molecules from the outer to the inner leaflet. This cracking-in may be accompanied by transient, incomplete leakage from the aqueous cores of the liposomes observed, typically, for some seconds or less. The mismatch of the lipopeptide with the lipid leaflet geometry, expressed for example in terms of a spontaneous curvature, has two effects. First, it affects the threshold for transient leakage as described. Second, it controls the rate of equilibrium leakage proceeding as the lipopeptide has reached sufficient local concentrations in both leaflets to form quasi-toroidal defects or pores. Both modes of action, transient and equilibrium leakage, synergize for intermediate chain lengths such as the native, i.e., for PSD-C10. These mechanisms may also account for the reported chain-length dependent specificities of antibiotic action against the target bacteria.
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Affiliation(s)
- Jessica Steigenberger
- Department of Pharmaceutical Technology and Biopharmacy, University of Freiburg, Freiburg, Germany
| | - Yentl Verleysen
- NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Niels Geudens
- NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - José C Martins
- NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Heiko Heerklotz
- Department of Pharmaceutical Technology and Biopharmacy, University of Freiburg, Freiburg, Germany.,Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada.,Signaling Research Centers BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
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Regenold M, Steigenberger J, Siniscalchi E, Dunne M, Casettari L, Heerklotz H, Allen C. Determining critical parameters that influence in vitro performance characteristics of a thermosensitive liposome formulation of vinorelbine. J Control Release 2020; 328:551-561. [DOI: 10.1016/j.jconrel.2020.08.059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 08/26/2020] [Accepted: 08/28/2020] [Indexed: 02/06/2023]
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Eckhardt D, Schnur J, Steigenberger J, Kalie L, Massing U, Pabst G, Heerklotz HH. Eutectic Explains Function of Thermoresponsive Liposomes - Resolving the Lysolipid Paradox. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.1346] [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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Steigenberger J. Contribution to the mechanics of worm-like motion systems and artificial muscles. Biomech Model Mechanobiol 2003; 2:37-57. [PMID: 14586816 DOI: 10.1007/s10237-003-0027-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [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: 11/05/2001] [Accepted: 12/12/2002] [Indexed: 11/30/2022]
Abstract
In this paper the author presents a mathematical model of a device that can be seen as a segment of an artificial worm (following the paradigm "earthworm") and as an artificial muscle as well. Confining considerations to statics, the model shows up as an ordinary parameter-dependent boundary value problem. It is tackled numerically in various particular forms by means of Maple and thus gives a good view of the segment's behavior during inflation and under longitudinal load. Segments of maximal volume present a useful preliminary stage of the investigations.
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Affiliation(s)
- J Steigenberger
- Institut für Mathematik, Technische Universität Ilmenau, Weimarer Strasse 25, 98693 Ilmenau, Germany.
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