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Müller W, Beales PA, Muniz AR, Jeuken LJC. Unraveling the Phase Behavior, Mechanical Stability, and Protein Reconstitution Properties of Polymer-Lipid Hybrid Vesicles. Biomacromolecules 2023; 24:4156-4169. [PMID: 37539954 PMCID: PMC10498451 DOI: 10.1021/acs.biomac.3c00498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/20/2023] [Indexed: 08/05/2023]
Abstract
Hybrid vesicles consisting of natural phospholipids and synthetic amphiphilic copolymers have shown remarkable material properties and potential for biotechnology, combining the robustness of polymers with the biocompatibility of phospholipid membranes. To predict and optimize the mixing behavior of lipids and copolymers, as well as understand the interaction between the hybrid membrane and macromolecules like membrane proteins, a comprehensive understanding at the molecular level is essential. This can be achieved by a combination of molecular dynamics simulations and experiments. Here, simulations of POPC and PBD22-b-PEO14 hybrid membranes are shown, uncovering different copolymer configurations depending on the polymer-to-lipid ratio. High polymer concentrations created thicker membranes with an extended polymer conformation, while high lipid content led to the collapse of the polymer chain. High concentrations of polymer were further correlated with a decreased area compression modulus and altered lateral pressure profiles, hypothesized to result in the experimentally observed improvement in membrane protein reconstitution and resistance toward destabilization by detergents. Finally, simulations of a WALP peptide embedded in the bilayer showed that only membranes with up to 50% polymer content favored a transmembrane configuration. These simulations correlate with previous and new experimental results and provide a deeper understanding of the properties of lipid-copolymer hybrid membranes.
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Affiliation(s)
- Wagner
A. Müller
- Department
of Chemical Engineering, Universidade Federal
do Rio Grande do Sul, Porto
Alegre 90035-003, Brazil
| | - Paul A. Beales
- School
of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K.
| | - André R. Muniz
- Department
of Chemical Engineering, Universidade Federal
do Rio Grande do Sul, Porto
Alegre 90035-003, Brazil
| | - Lars J. C. Jeuken
- Leiden
Institute of Chemistry, University Leiden, PO Box 9502, 2300RA Leiden, The
Netherlands
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2
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Povilaitis SC, Webb LJ. Leaflet-Dependent Effect of Anionic Lipids on Membrane Insertion by Cationic Cell-Penetrating Peptides. J Phys Chem Lett 2023; 14:5841-5849. [PMID: 37339513 PMCID: PMC10478718 DOI: 10.1021/acs.jpclett.3c00725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/22/2023]
Abstract
Cationic membrane-permeating peptides can cross membranes unassisted by transmembrane protein machinery, and there is consensus that anionic lipids facilitate this process. Although membranes are asymmetric in lipid composition, investigations of the impact of anionic lipids on peptide-membrane insertion in model vesicles primarily use symmetric anionic lipid distributions between bilayer leaflets. Here, we investigate the leaflet-specific influence of three anionic lipid headgroups [phosphatidic acid (PA), phosphatidylserine (PS), and phosphatidylglycerol (PG)] on insertion into model membranes by three cationic membrane-permeating peptides (NAF-144-67, R6W3, and WWWK). We report that outer leaflet anionic lipids enhanced peptide-membrane insertion for all peptides while inner leaflet anionic lipids did not have a significant effect except in the case of NAF-144-67 incubated with PA-containing vesicles. The insertion enhancement was headgroup-dependent for arginine-containing peptides but not WWWK. These results provide significant new insight into the potential role of membrane asymmetry in insertion of peptides into model membranes.
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Affiliation(s)
- Sydney C Povilaitis
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Lauren J Webb
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
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3
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Cortes-Galvez D, Dangerfield JA, Metzner C. Extracellular Vesicles and Their Membranes: Exosomes vs. Virus-Related Particles. MEMBRANES 2023; 13:397. [PMID: 37103824 PMCID: PMC10146078 DOI: 10.3390/membranes13040397] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/28/2023] [Accepted: 03/29/2023] [Indexed: 06/19/2023]
Abstract
Cells produce nanosized lipid membrane-enclosed vesicles which play important roles in intercellular communication. Interestingly, a certain type of extracellular vesicle, termed exosomes, share physical, chemical, and biological properties with enveloped virus particles. To date, most similarities have been discovered with lentiviral particles, however, other virus species also frequently interact with exosomes. In this review, we will take a closer look at the similarities and differences between exosomes and enveloped viral particles, with a focus on events taking place at the vesicle or virus membrane. Since these structures present an area with an opportunity for interaction with target cells, this is relevant for basic biology as well as any potential research or medical applications.
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Affiliation(s)
- Daniela Cortes-Galvez
- AG Histology and Embryology, Institute of Morphology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
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4
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Saha T, Heuer A, Galic M. Systematic analysis of curvature-dependent lipid dynamics in a stochastic 3D membrane model. SOFT MATTER 2023; 19:1330-1341. [PMID: 36692259 DOI: 10.1039/d2sm01260j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
To minimize the free energy of the system, lipid membranes display curvature-dependent rearrangements at the local and global scale. The optimal membrane shape is generally approximated by averaging the curvature preference of individual lipids across the whole surface. Potential stress due to imperfections in lipid packing caused by local lipid inhomogeneities, however, is frequently neglected. Here, we developed a stochastic 3D membrane model to investigate the relevance of this parameter for shape-dependent lipid and membrane dynamics. A systematic analysis of the discretized Helfrich type Hamiltonian indicates that stress-energy arising from imperfections in packing is analogous to van der Waals interactions, jointly determining membrane shape and localization of curvature-sensitive lipids based on their relative strengths. Insights from this work can be used to characterize natural and design synthetic agents for membrane-shape changes.
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Affiliation(s)
- Tanumoy Saha
- Institute of Medical Physics and Biophysics, University of Muenster, Germany.
- Cells in Motion' Interfaculty Centre, University of Muenster, Germany.
- CIM-IMPRS Graduate School, Muenster, Germany
| | - Andreas Heuer
- Cells in Motion' Interfaculty Centre, University of Muenster, Germany.
- Institute of Physical Chemistry, University of Muenster, Germany
| | - Milos Galic
- Institute of Medical Physics and Biophysics, University of Muenster, Germany.
- Cells in Motion' Interfaculty Centre, University of Muenster, Germany.
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5
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Nakano M, Nakao H, Yoshida S, Fukuda M, Imai M, Ikeda K. Energetic and Structural Insights into Phospholipid Transfer from Membranes with Different Curvatures by Time-Resolved Neutron Scattering. J Phys Chem Lett 2022; 13:6024-6030. [PMID: 35748601 DOI: 10.1021/acs.jpclett.2c01080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Understanding how lipid dynamics change with membrane curvature is important given that biological membranes constantly change their curvature and morphology through membrane fusion and endo-/exocytosis. Here, we used time-resolved small-angle neutron scattering and time-resolved fluorescence to characterize the properties and dynamics of phospholipids in vesicles with different curvatures. Dissociation of phospholipids from vesicles required traversing an energy barrier comprising positive enthalpy and negative entropy. However, lipids in membranes with high positive curvature have dense acyl chain packing and loose headgroup packing, leading to hydrophobic hydration due to water penetration into the membrane. These properties were found to lower the hydrophobic hydration enhancement associated with phospholipid dissociation and mitigate the acyl chain packing of lipids adjacent to the space created by the lipid dissociation, resulting in an increase in activation entropy. The results of this study provide important insights into the functions of biomembranes in relation to their dynamic structural changes.
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Affiliation(s)
- Minoru Nakano
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Hiroyuki Nakao
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Shigeharu Yoshida
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Masakazu Fukuda
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Manjiro Imai
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Keisuke Ikeda
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
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6
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Multiscale Dynamics of Lipid Vesicles in Polymeric Microenvironment. MEMBRANES 2022; 12:membranes12070640. [PMID: 35877843 PMCID: PMC9318666 DOI: 10.3390/membranes12070640] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/15/2022] [Accepted: 06/18/2022] [Indexed: 02/06/2023]
Abstract
Understanding dynamic and complex interaction of biological membranes with extracellular matrices plays a crucial role in controlling a variety of cell behavior and functions, from cell adhesion and growth to signaling and differentiation. Tremendous interest in tissue engineering has made it possible to design polymeric scaffolds mimicking the topology and mechanical properties of the native extracellular microenvironment; however, a fundamental question remains unanswered: that is, how the viscoelastic extracellular environment modifies the hierarchical dynamics of lipid membranes. In this work, we used aqueous solutions of poly(ethylene glycol) (PEG) with different molecular weights to mimic the viscous medium of cells and nearly monodisperse unilamellar DMPC/DMPG liposomes as a membrane model. Using small-angle X-ray scattering (SAXS), dynamic light scattering, temperature-modulated differential scanning calorimetry, bulk rheology, and fluorescence lifetime spectroscopy, we investigated the structural phase map and multiscale dynamics of the liposome–polymer mixtures. The results suggest an unprecedented dynamic coupling between polymer chains and phospholipid bilayers at different length/time scales. The microviscosity of the lipid bilayers is directly influenced by the relaxation of the whole chain, resulting in accelerated dynamics of lipids within the bilayers in the case of short chains compared to the polymer-free liposome case. At the macroscopic level, the gel-to-fluid transition of the bilayers results in a remarkable thermal-stiffening behavior of polymer–liposome solutions that can be modified by the concentration of the liposomes and the polymer chain length.
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Perez-Salas U, Garg S, Gerelli Y, Porcar L. Deciphering lipid transfer between and within membranes with time-resolved small-angle neutron scattering. CURRENT TOPICS IN MEMBRANES 2021; 88:359-412. [PMID: 34862031 DOI: 10.1016/bs.ctm.2021.10.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This review focuses on time-resolved neutron scattering, particularly time-resolved small angle neutron scattering (TR-SANS), as a powerful in situ noninvasive technique to investigate intra- and intermembrane transport and distribution of lipids and sterols in lipid membranes. In contrast to using molecular analogues with potentially large chemical tags that can significantly alter transport properties, small angle neutron scattering relies on the relative amounts of the two most abundant isotope forms of hydrogen: protium and deuterium to detect complex membrane architectures and transport processes unambiguously. This review discusses advances in our understanding of the mechanisms that sustain lipid asymmetry in membranes-a key feature of the plasma membrane of cells-as well as the transport of lipids between membranes, which is an essential metabolic process.
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Affiliation(s)
- Ursula Perez-Salas
- Physics Department, University of Illinois at Chicago, Chicago, IL, United States.
| | - Sumit Garg
- Physics Department, University of Illinois at Chicago, Chicago, IL, United States
| | - Yuri Gerelli
- Department of Life and Environmental Sciences, Universita` Politecnica delle Marche, Ancona, Italy
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