1
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Aizik G, Ostertag-Hill CA, Chakraborty P, Choi W, Pan M, Mankus DV, Lytton-Jean AKR, Kohane DS. Injectable hydrogel based on liposome self-assembly for controlled release of small hydrophilic molecules. Acta Biomater 2024; 183:101-110. [PMID: 38834149 PMCID: PMC11239275 DOI: 10.1016/j.actbio.2024.05.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 05/20/2024] [Accepted: 05/28/2024] [Indexed: 06/06/2024]
Abstract
Controlled release of low molecular weight hydrophilic drugs, administered locally, allows maintenance of high concentrations at the target site, reduces systemic side effects, and improves patient compliance. Injectable hydrogels are commonly used as a vehicle. However, slow release of low molecular weight hydrophilic drugs is very difficult to achieve, mainly due to a rapid diffusion of the drug out of the drug delivery system. Here we present an injectable and self-healing hydrogel based entirely on the self-assembly of liposomes. Gelation of liposomes, without damaging their structural integrity, was induced by modifying the cholesterol content and surface charge. The small hydrophilic molecule, sodium fluorescein, was loaded either within the extra-liposomal space or encapsulated into the aqueous cores of the liposomes. This encapsulation strategy enabled the achievement of controlled and adjustable release profiles, dependent on the mechanical strength of the gel. The hydrogel had a high mechanical strength, minimal swelling, and slow degradation. The liposome-based hydrogel had prolonged mechanical stability in vivo with benign tissue reaction. This work presents a new class of injectable hydrogel that holds promise as a versatile drug delivery system. STATEMENT OF SIGNIFICANCE: The porous nature of hydrogels poses a challenge for delivering small hydrophilic drug, often resulting in initial burst release and shorten duration of release. This issue is particularly pronounced with physically crosslinked hydrogels, since their matrix can swell and dissipate rapidly, but even in cases where the polymers in the hydrogel are covalently cross-linked, small molecules can be rapidly released through its porous mesh. Here we present an injectable self-healing hydrogel based entirely on the self-assembly of liposomes. Small hydrophilic molecules were entrapped inside the extra-liposomal space or loaded into the aqueous cores of the liposomes, allowing controlled and tunable release profiles.
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Affiliation(s)
- Gil Aizik
- Laboratory for Biomaterials and Drug Delivery, Boston Children's Hospital, Harvard Medical School, Harvard Institutes of Medicine, Boston, MA 02115, USA; Department of Anesthesiology, Critical Care, and Pain Management, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Claire A Ostertag-Hill
- Laboratory for Biomaterials and Drug Delivery, Boston Children's Hospital, Harvard Medical School, Harvard Institutes of Medicine, Boston, MA 02115, USA; Department of Surgery, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Priyadarshi Chakraborty
- Laboratory for Biomaterials and Drug Delivery, Boston Children's Hospital, Harvard Medical School, Harvard Institutes of Medicine, Boston, MA 02115, USA; Department of Anesthesiology, Critical Care, and Pain Management, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Wonmin Choi
- Laboratory for Biomaterials and Drug Delivery, Boston Children's Hospital, Harvard Medical School, Harvard Institutes of Medicine, Boston, MA 02115, USA; Department of Anesthesiology, Critical Care, and Pain Management, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Michelle Pan
- Laboratory for Biomaterials and Drug Delivery, Boston Children's Hospital, Harvard Medical School, Harvard Institutes of Medicine, Boston, MA 02115, USA; Department of Anesthesiology, Critical Care, and Pain Management, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - David V Mankus
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Abigail K R Lytton-Jean
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Daniel S Kohane
- Laboratory for Biomaterials and Drug Delivery, Boston Children's Hospital, Harvard Medical School, Harvard Institutes of Medicine, Boston, MA 02115, USA; Department of Anesthesiology, Critical Care, and Pain Management, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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2
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Hossein A, Beaven AH, Sapp K, Sodt AJ. Softening in Two-Component Lipid Mixtures by Spontaneous Curvature Variance. J Phys Chem B 2024; 128:6317-6326. [PMID: 38889363 DOI: 10.1021/acs.jpcb.3c08117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
The bending modulus of a lipid bilayer quantifies its mechanical resistance to curvature. It is typically understood in terms of thickness; e.g., thicker bilayers are usually stiffer. Here, we describe an additional and powerful molecular determinant of stiffness─the variance in the distribution of curvature sensitivity of lipids and lipid conformations. Zwitterionic choline and ethanolamine headgroups of glycerophospholipids dynamically explore inter- and intraspecies interactions, leading to transient clustering. We demonstrate that these clusters couple strongly to negative curvature, exciting undulatory membrane modes and reducing the apparent bending modulus. Three force fields (Martini 2, Martini 3, and all-atom CHARMM C36) each show the effect to a different extent, with the coarse-grained Martini models showing the most clustering and thus the most softening. The theory is a guide to understanding the stiffness of biological membranes with their complex composition, as well as how choices of force field parameterization are translated into mechanical stiffness.
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Affiliation(s)
- Amirali Hossein
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland 20892, United States
| | - Andrew H Beaven
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland 20892, United States
- Postdoctoral Research Associate Program, National Institute of General Medical Sciences, Bethesda, Maryland 20892, United States
| | - Kayla Sapp
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland 20892, United States
| | - Alexander J Sodt
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland 20892, United States
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3
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Krogman WL, Woodard T, McKay RSF. Anesthetic Mechanisms: Synergistic Interactions With Lipid Rafts and Voltage-Gated Sodium Channels. Anesth Analg 2024; 139:92-106. [PMID: 37968836 DOI: 10.1213/ane.0000000000006738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
Despite successfully utilizing anesthetics for over 150 years, the mechanism of action remains relatively unknown. Recent studies have shown promising results, but due to the complex interactions between anesthetics and their targets, there remains a clear need for further mechanistic research. We know that lipophilicity is directly connected to anesthetic potency since lipid solubility relates to anesthetic partition into the membrane. However, clinically relevant concentrations of anesthetics do not significantly affect lipid bilayers but continue to influence various molecular targets. Lipid rafts are derived from liquid-ordered phases of the plasma membrane that contain increased concentrations of cholesterol and sphingomyelin and act as staging platforms for membrane proteins, including ion channels. Although anesthetics do not perturb membranes at clinically relevant concentrations, they have recently been shown to target lipid rafts. In this review, we summarize current research on how different types of anesthetics-local, inhalational, and intravenous-bind and affect both lipid rafts and voltage-gated sodium channels, one of their major targets, and how those effects synergize to cause anesthesia and analgesia. Local anesthetics block voltage-gated sodium channel pores while also disrupting lipid packing in ordered membranes. Inhalational anesthetics bind to the channel pore and the voltage-sensing domain while causing an increase in the number, size, and diameter of lipid rafts. Intravenous anesthetics bind to the channel primarily at the voltage-sensing domain and the selectivity filter, while causing lipid raft perturbation. These changes in lipid nanodomain structure possibly give proteins access to substrates that have translocated as a result of these structural alterations, resulting in lipid-driven anesthesia. Overall, anesthetics can impact channel activity either through direct interaction with the channel, indirectly through the lipid raft, or both. Together, these result in decreased sodium ion flux into the cell, disrupting action potentials and producing anesthetic effects. However, more research is needed to elucidate the indirect mechanisms associated with channel disruption through the lipid raft, as not much is known about anionic lipid products and their influence over voltage-gated sodium channels. Anesthetics' effect on S-palmitoylation, a promising mechanism for direct and indirect influence over voltage-gated sodium channels, is another auspicious avenue of research. Understanding the mechanisms of different types of anesthetics will allow anesthesiologists greater flexibility and more specificity when treating patients.
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Affiliation(s)
- William L Krogman
- From the Department of Anesthesiology, University of Kansas School of Medicine - Wichita, Wichita, Kansas
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4
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Lauritsen L, Szomek M, Hornum M, Reinholdt P, Kongsted J, Nielsen P, Brewer JR, Wüstner D. Ratiometric fluorescence nanoscopy and lifetime imaging of novel Nile Red analogs for analysis of membrane packing in living cells. Sci Rep 2024; 14:13748. [PMID: 38877068 PMCID: PMC11178856 DOI: 10.1038/s41598-024-64180-8] [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: 12/18/2023] [Accepted: 06/05/2024] [Indexed: 06/16/2024] Open
Abstract
Subcellular membranes have complex lipid and protein compositions, which give rise to organelle-specific membrane packing, fluidity, and permeability. Due to its exquisite solvent sensitivity, the lipophilic fluorescence dye Nile Red has been used extensively to study membrane packing and polarity. Further improvement of Nile Red can be achieved by introducing electron-donating or withdrawing functional groups. Here, we compare the potential of derivatives of Nile Red with such functional substitutions for super-resolution fluorescence microscopy of lipid packing in model membranes and living cells. All studied Nile Red derivatives exhibit cholesterol-dependent fluorescence changes in model membranes, as shown by spectrally resolved stimulated emission depletion (STED) microscopy. STED imaging of Nile Red probes in cells reveals lower membrane packing in fibroblasts from healthy subjects compared to those from patients suffering from Niemann Pick type C1 (NPC1) disease, a lysosomal storage disorder with accumulation of cholesterol and sphingolipids in late endosomes and lysosomes. We also find small but consistent changes in the fluorescence lifetime of the Nile Red derivatives in NPC1 cells, suggesting altered hydrogen-bonding capacity in their membranes. All Nile Red derivatives are essentially non-fluorescent in water but increase their brightness in membranes, allowing for their use in MINFLUX single molecule tracking experiments. Our study uncovers the potential of Nile Red probes with functional substitutions for nanoscopic membrane imaging.
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Affiliation(s)
- Line Lauritsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Maria Szomek
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Mick Hornum
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Peter Reinholdt
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Jacob Kongsted
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Poul Nielsen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Jonathan R Brewer
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Daniel Wüstner
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark.
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5
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Landiech S, Elias M, Lapèze P, Ajiyel H, Plancke M, González-Bermúdez B, Laborde A, Mesnilgrente F, Bourrier D, Berti D, Montis C, Mazenq L, Baldo J, Roux C, Delarue M, Joseph P. Parallel on-chip micropipettes enabling quantitative multiplexed characterization of vesicle mechanics and cell aggregates rheology. APL Bioeng 2024; 8:026122. [PMID: 38894959 PMCID: PMC11184969 DOI: 10.1063/5.0193333] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 05/24/2024] [Indexed: 06/21/2024] Open
Abstract
Micropipette aspiration (MPA) is one of the gold standards for quantifying biological samples' mechanical properties, which are crucial from the cell membrane scale to the multicellular tissue. However, relying on the manipulation of individual home-made glass pipettes, MPA suffers from low throughput and no automation. Here, we introduce the sliding insert micropipette aspiration method, which permits parallelization and automation, thanks to the insertion of tubular pipettes, obtained by photolithography, within microfluidic channels. We show its application both at the lipid bilayer level, by probing vesicles to measure membrane bending and stretching moduli, and at the tissue level by quantifying the viscoelasticity of 3D cell aggregates. This approach opens the way to high-throughput, quantitative mechanical testing of many types of biological samples, from vesicles and individual cells to cell aggregates and explants, under dynamic physico-chemical stimuli.
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Affiliation(s)
| | - Marianne Elias
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Pierre Lapèze
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Hajar Ajiyel
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Marine Plancke
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Blanca González-Bermúdez
- Center for Biomedical Technology, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Spain and Department of Materials Science, ETSI de Caminos, Canales y Puertos, Universidad Politécnica de Madrid, Madrid, Spain
| | - Adrian Laborde
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | | | - David Bourrier
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Debora Berti
- CSGI and Department of Chemistry, University of Florence, Sesto Fiorentino, Italy
| | - Costanza Montis
- CSGI and Department of Chemistry, University of Florence, Sesto Fiorentino, Italy
| | - Laurent Mazenq
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Jérémy Baldo
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Clément Roux
- SoftMat, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Morgan Delarue
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Pierre Joseph
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
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6
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Jahnke K, Pavlovic M, Xu W, Chen A, Knowles TPJ, Arriaga LR, Weitz DA. Polysaccharide functionalization reduces lipid vesicle stiffness. Proc Natl Acad Sci U S A 2024; 121:e2317227121. [PMID: 38771870 PMCID: PMC11145274 DOI: 10.1073/pnas.2317227121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 04/15/2024] [Indexed: 05/23/2024] Open
Abstract
The biophysical properties of lipid vesicles are important for their stability and integrity, key parameters that control the performance when these vesicles are used for drug delivery. The vesicle properties are determined by the composition of lipids used to form the vesicle. However, for a given lipid composition, they can also be tailored by tethering polymers to the membrane. Typically, synthetic polymers like polyethyleneglycol are used to increase vesicle stability, but the use of polysaccharides in this context is much less explored. Here, we report a general method for functionalizing lipid vesicles with polysaccharides by binding them to cholesterol. We incorporate the polysaccharides on the outer membrane leaflet of giant unilamellar vesicles (GUVs) and investigate their effect on membrane mechanics using micropipette aspiration. We find that the presence of the glycolipid functionalization produces an unexpected softening of GUVs with fluid-like membranes. By contrast, the functionalization of GUVs with polyethylene glycol does not reduce their stretching modulus. This work provides the potential means to study membrane-bound meshworks of polysaccharides similar to the cellular glycocalyx; moreover, it can be used for tuning the mechanical properties of drug delivery vehicles.
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Affiliation(s)
- Kevin Jahnke
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA02138
| | - Marko Pavlovic
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA02138
| | - Wentao Xu
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA02138
| | - Anqi Chen
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA02138
| | - Tuomas P. J. Knowles
- Yusuf Hamied Department of Chemistry, University of Cambridge, CambridgeCB2 1EW, United Kingdom
| | - Laura R. Arriaga
- Department of Theoretical Condensed Matter Physics, Condensed Matter Physics Center and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, Madrid28049, Spain
| | - David A. Weitz
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA02138
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA02115
- Department of Physics, Harvard University, Cambridge, MA02138
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7
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Mitra S, Chandersekhar B, Li Y, Coopershlyak M, Mahoney ME, Evans B, Koenig R, Hall SCL, Klösgen B, Heinrich F, Deslouches B, Tristram-Nagle S. Novel non-helical antimicrobial peptides insert into and fuse lipid model membranes. SOFT MATTER 2024; 20:4088-4101. [PMID: 38712559 PMCID: PMC11109824 DOI: 10.1039/d4sm00220b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 04/26/2024] [Indexed: 05/08/2024]
Abstract
This research addresses the growing menace of antibiotic resistance by exploring antimicrobial peptides (AMPs) as alternatives to conventional antibiotics. Specifically, we investigate two linear amphipathic AMPs, LE-53 (12-mer) and LE-55 (16-mer), finding that the shorter LE-53 exhibits greater bactericidal activity against both Gram-negative (G(-)) and Gram-positive (G(+)) bacteria. Remarkably, both AMPs are non-toxic to eukaryotic cells. The heightened effectiveness of LE-53 is attributed to its increased hydrophobicity (H) compared to LE-55. Circular dichroism (CD) reveals that LE-53 and LE-55 both adopt β-sheet and random coil structures in lipid model membranes (LMMs) mimicking G(-) and G(+) bacteria, so secondary structure is not the cause of the potency difference. X-ray diffuse scattering (XDS) reveals increased lipid chain order in LE-53, a potential key distinction. Additionally, XDS study uncovers a significant link between LE-53's upper hydrocarbon location in G(-) and G(+) LMMs and its efficacy. Neutron reflectometry (NR) confirms the AMP locations determined using XDS. Solution small angle X-ray scattering (SAXS) demonstrates LE-53's ability to induce vesicle fusion in bacterial LMMs without affecting eukaryotic LMMs, offering a promising strategy to combat antibiotic-resistant strains while preserving human cell integrity, whereas LE-55 has a smaller ability to induce fusion.
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Affiliation(s)
- Saheli Mitra
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | - Bhairavi Chandersekhar
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | - Yunshu Li
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | - Mark Coopershlyak
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | - Margot E Mahoney
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | - Brandt Evans
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | - Rachel Koenig
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | - Stephen C L Hall
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire, OX11 0QX, UK
| | - Beate Klösgen
- University of Southern Denmark, Dept. Physics, Chemistry & Pharmacy, PhyLife, Campusvej 55, Odense M5230, Denmark
| | - Frank Heinrich
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Berthony Deslouches
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Stephanie Tristram-Nagle
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
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8
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Himbert S, Gaboo D, Brookes E, Nagle JF, Rheinstädter MC. MEDUSA: A cloud-based tool for the analysis of X-ray diffuse scattering to obtain the bending modulus from oriented membrane stacks. PLoS Comput Biol 2024; 20:e1011749. [PMID: 38190400 PMCID: PMC10798642 DOI: 10.1371/journal.pcbi.1011749] [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: 07/14/2023] [Revised: 01/19/2024] [Accepted: 12/11/2023] [Indexed: 01/10/2024] Open
Abstract
An important mechanical property of cells is their membrane bending modulus, κ. Here, we introduce MEDUSA (MEmbrane DiffUse Scattering Analysis), a cloud-based analysis tool to determine the bending modulus, κ, from the analysis of X-ray diffuse scattering. MEDUSA uses GPU (graphics processing unit) accelerated hardware and a parallelized algorithm to run the calculations efficiently in a few seconds. MEDUSA's graphical user interface allows the user to upload 2-dimensional data collected from different sources, perform background subtraction and distortion corrections, select regions of interest, run the fitting procedure and output the fitted parameters, the membranes' bending modulus κ, and compressional modulus B.
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Affiliation(s)
- Sebastian Himbert
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
- Origins Institute, McMaster University, Hamilton, Ontario, Canada
| | - Dorian Gaboo
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
- Origins Institute, McMaster University, Hamilton, Ontario, Canada
| | - Emre Brookes
- Department of Chemistry and Biochemistry, University of Montana, Missoula, Montana, United States of America
| | - John F. Nagle
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Maikel C. Rheinstädter
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
- Origins Institute, McMaster University, Hamilton, Ontario, Canada
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9
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Hossein A, Beaven AH, Sapp K, Sodt AJ. Softening in two-component lipid mixtures by spontaneous curvature variance. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.12.571323. [PMID: 38168180 PMCID: PMC10760180 DOI: 10.1101/2023.12.12.571323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
The bending modulus of a lipid bilayer quantifies its mechanical resistance to curvature. It is typically understood in terms of thickness, e.g., thicker bilayers are stiffer. Here, we describe an additional and powerful molecular determinant of stiffness - the variance in the distribution of curvature sensitivity of lipids and lipid conformations. Zwitterionic choline and ethanolamine head-groups of glycero-phospholipids dynamically explore inter- and intra-species interactions, leading to transient clustering. We demonstrate that these clusters couple strongly to negative curvature, exciting undulatory membrane modes and reducing the apparent bending modulus. Three forcefields (Martini 2, Martini 3, and all-atom CHARMM C36) each show the effect to a different extent, with the coarse-grained Martini models showing the most clustering and thus the most softening. The theory is a guide to understanding the stiffness of biological membranes with their complex composition, as well as how choices of forcefield parameterization are translated into mechanical stiffness.
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Affiliation(s)
- Amirali Hossein
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, United States
| | - Andrew H Beaven
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, United States
- Postdoctoral Research Associate Program, National Institute of General Medical Sciences, Bethesda, MD 20892, United States
| | - Kayla Sapp
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, United States
| | - Alexander J Sodt
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, United States
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10
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Pöhnl M, Trollmann MFW, Böckmann RA. Nonuniversal impact of cholesterol on membranes mobility, curvature sensing and elasticity. Nat Commun 2023; 14:8038. [PMID: 38081812 PMCID: PMC10713574 DOI: 10.1038/s41467-023-43892-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
Biological membranes, composed mainly of phospholipids and cholesterol, play a vital role as cellular barriers. They undergo localized reshaping in response to environmental cues and protein interactions, with the energetics of deformations crucial for exerting biological functions. This study investigates the non-universal role of cholesterol on the structure and elasticity of saturated and unsaturated lipid membranes. Our study uncovers a highly cooperative relationship between thermal membrane bending and local cholesterol redistribution, with cholesterol showing a strong preference for the compressed membrane leaflet. Remarkably, in unsaturated membranes, increased cholesterol mobility enhances cooperativity, resulting in membrane softening despite membrane thickening and lipid compression caused by cholesterol. These findings elucidate the intricate interplay between thermodynamic forces and local molecular interactions that govern collective properties of membranes.
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Affiliation(s)
- Matthias Pöhnl
- Computational Biology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Marius F W Trollmann
- Computational Biology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
- Erlangen National High Perfomance Computing Center (NHR@FAU), Erlangen, Germany
| | - Rainer A Böckmann
- Computational Biology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
- Erlangen National High Perfomance Computing Center (NHR@FAU), Erlangen, Germany.
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11
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Gamage YI, Pan J. Elucidating the Influence of Lipid Composition on Bilayer Perturbations Induced by the N-terminal Region of the Huntingtin Protein. BIOPHYSICA 2023; 3:582-597. [PMID: 38737720 PMCID: PMC11087071 DOI: 10.3390/biophysica3040040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
Understanding the membrane interactions of the N-terminal 17 residues of the huntingtin protein (HttN) is essential for unraveling its role in cellular processes and its impact on huntingtin misfolding. In this study, we used atomic force microscopy (AFM) to examine the effects of lipid specificity in mediating bilayer perturbations induced by HttN. Across various lipid environments, the peptide consistently induced bilayer disruptions in the form of holes. Notably, our results unveiled that cholesterol enhanced bilayer perturbation induced by HttN, while phosphatidylethanolamine (PE) lipids suppressed hole formation. Furthermore, anionic phosphatidylglycerol (PG) and cardiolipin lipids, along with cholesterol at high concentrations, promoted the formation of double-bilayer patches. This unique structure suggests that the synergy among HttN, anionic lipids, and cholesterol can enhance bilayer fusion, potentially by facilitating lipid intermixing between adjacent bilayers. Additionally, our AFM-based force spectroscopy revealed that HttN enhanced the mechanical stability of lipid bilayers, as evidenced by an elevated bilayer puncture force. These findings illuminate the complex interplay between HttN and lipid membranes and provide useful insights into the role of lipid composition in modulating membrane interactions with the huntingtin protein.
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Affiliation(s)
| | - Jianjun Pan
- Department of Physics, University of South Florida, Tampa, FL 33620
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12
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Manafirad A, Menendez CA, Perez-Lemus GR, Thayumanavan S, de Pablo JJ, Dinsmore AD. Structural and Mechanical Response of Two-Component Photoswitchable Lipid Bilayer Vesicles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:15932-15941. [PMID: 37922483 DOI: 10.1021/acs.langmuir.3c01764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2023]
Abstract
Optical control of phospholipids is an attractive option for the rapid, reversible, and tunable manipulation of membrane structure and dynamics. Azo-PC, a lipid with an azobenzene group within one acyl chain, undergoes a light-induced trans-to-cis isomerization and thus arises as a powerful tool for manipulating lipid order and dynamics. Here, we report on vesicle-scale micropipette measurements and atomistic simulations to probe the elastic stretching modulus, water permeability, toughness, thickness, and membrane area upon isomerization. We investigated both dynamics and steady-state properties. In pure azo-PC membranes, we found that the molecular area in trans was 16% smaller than that in cis, the membrane's stretching modulus kA was 2.5 ± 0.3 times greater, and the water permeability PW was 3.5 ± 0.5 times smaller. We also studied mixtures of azo-PC with the miscible, unsaturated lipid DOPC. Atomistic molecular dynamics simulations show how the membrane thickness, chain order, and correlations across membrane leaflets explain the experimental data. Together, these data show how one rotating bond changes the molecular- and membrane-scale properties. These results will be useful for photopharmacology and for developing new materials whose permeability, elasticity, and toughness may be switched on demand.
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Affiliation(s)
- Arash Manafirad
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, United States
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Cintia A Menendez
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
- INQUISUR, Departamento de Quimica, Universidad Nacional del Sur (UNS)-CONICET, Avenida Alem 1253, 8000 Bahía Blanca, Argentina
| | - Gustavo R Perez-Lemus
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - S Thayumanavan
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Juan J de Pablo
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Anthony D Dinsmore
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, United States
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13
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Xu J, Karra V, Large DE, Auguste DT, Hung FR. Understanding the Mechanical Properties of Ultradeformable Liposomes Using Molecular Dynamics Simulations. J Phys Chem B 2023; 127:9496-9512. [PMID: 37879075 PMCID: PMC10641833 DOI: 10.1021/acs.jpcb.3c04386] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 09/19/2023] [Accepted: 10/04/2023] [Indexed: 10/27/2023]
Abstract
Improving drug delivery efficiency to solid tumor sites is a central challenge in anticancer therapeutic research. Our previous experimental study (Guo et al., Nat. Commun. 2018, 9, 130) showed that soft, elastic liposomes had increased uptake and accumulation in cancer cells and tumors in vitro and in vivo respectively, relative to rigid particles. As a first step toward understanding how liposomes' molecular structure and composition modulates their elasticity, we performed all-atom and coarse-grained classical molecular dynamics (MD) simulations of lipid bilayers formed by mixing a long-tailed unsaturated phospholipid with a short-tailed saturated lipid with the same headgroup. The former types of phospholipids considered were 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dipalmitoleoyl-sn-glycero-3-phosphocholine (termed here DPMPC). The shorter saturated lipids examined were 1,2-diheptanoyl-sn-glycero-3-phosphocholine (DHPC), 1,2-didecanoyl-sn-glycero-3-phosphocholine (DDPC), 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC), and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). Several lipid concentrations and surface tensions were considered. Our results show that DOPC or DPMPC systems having 25-35 mol % of the shortest lipids DHPC or DDPC are the least rigid, having area compressibility moduli KA that are ∼10% smaller than the values observed in pure DOPC or DPMPC bilayers. These results agree with experimental measurements of the stretching modulus and lysis tension in liposomes with the same compositions. These mixed systems also have lower areas per lipid and form more uneven x-y interfaces with water, the tails of both primary and secondary lipids are more disordered, and the terminal methyl groups in the tails of the long lipid DOPC or DPMPC wriggle more in the vertical direction, compared to pure DOPC or DPMPC bilayers or their mixtures with the longer saturated lipid DLPC or DMPC. These observations confirm our hypothesis that adding increasing concentrations of the short unsaturated lipid DHPC or DDPC to DOPC or DPMPC bilayers alters lipid packing and thus makes the resulting liposomes more elastic and less rigid. No formation of lipid nanodomains was noted in our simulations, and no clear trends were observed in the lateral diffusivities of the lipids as the concentration, type of secondary lipid, and surface tension were varied.
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Affiliation(s)
- Jiaming Xu
- Department
of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Vyshnavi Karra
- Department
of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Danielle E. Large
- Department
of Bioengineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Debra T. Auguste
- Department
of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, United States
- Department
of Bioengineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Francisco R. Hung
- Department
of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, United States
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14
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Karal MAS, Billah MM, Ahmed M, Ahamed MK. A review on the measurement of the bending rigidity of lipid membranes. SOFT MATTER 2023; 19:8285-8304. [PMID: 37873600 DOI: 10.1039/d3sm00882g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
This review provides an overview of the latest developments in both experimental and simulation techniques used to assess the bending rigidity of lipid membranes. It places special emphasis on experimental methods that utilize model vesicles to manipulate lipid compositions and other experimental parameters to determine the bending rigidity of the membrane. It also describes two commonly used simulation methods for estimating bending rigidity. The impact of various factors on membrane bending rigidity is summarized, including cholesterol, lipids, salt concentration, surface charge, membrane phase state, peptides, proteins, and polyethylene glycol. These factors are shown to influence the bending rigidity, contributing to a better understanding of the biophysical properties of membranes and their role in biological processes. Furthermore, the review discusses future directions and potential advancements in this research field, highlighting areas where further investigation is required.
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Affiliation(s)
- Mohammad Abu Sayem Karal
- Department of Physics, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh.
| | - Md Masum Billah
- Department of Physics, Jashore University of Science and Technology, Jashore 7408, Bangladesh
| | - Marzuk Ahmed
- Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University, Shizuoka 422-8529, Japan
| | - Md Kabir Ahamed
- Radiation, Transport and Waste Safety Division, Bangladesh Atomic Energy Regulatory Authority, Agargaon, Dhaka 1207, Bangladesh
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15
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Gupta S, Soni J, Kumar A, Mandal T. Origin of the nonlinear structural and mechanical properties in oppositely curved lipid mixtures. J Chem Phys 2023; 159:165102. [PMID: 37873964 DOI: 10.1063/5.0167144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 10/04/2023] [Indexed: 10/25/2023] Open
Abstract
Structural and mechanical properties of membranes such as thickness, tail order, bending modulus and curvature energetics play crucial role in controlling various cellular functions that depend on the local lipid organization and membrane reshaping. While behavior of these biophysical properties are well understood in single component membranes, very little is known about how do they change in the mixed lipid membranes. Often various properties of the mixed lipid bilayers are assumed to change linearly with the mole fractions of the constituent lipids which, however, is true for "ideal" mixing only. In this study, using molecular dynamics simulations, we show that structural and mechanical properties of binary lipid mixture change nonlinearly with the lipid mole fractions, and the strength of the nonlinearity depends on two factors - spontaneous curvature difference and locally inhomogeneous interactions between the lipid components.
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Affiliation(s)
- Shivam Gupta
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Jatin Soni
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Awneesh Kumar
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Taraknath Mandal
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016, India
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16
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Ullmann K, Fachet L, Nirschl H, Leneweit G. Monolayer/Bilayer Equilibrium of Phospholipids in Gel or Liquid States: Interfacial Adsorption via Monomer or Liposome Diffusion? Gels 2023; 9:803. [PMID: 37888376 PMCID: PMC10606027 DOI: 10.3390/gels9100803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 09/25/2023] [Accepted: 09/30/2023] [Indexed: 10/28/2023] Open
Abstract
Phospholipids (PLs) are widely used in the pharma industry and a better understanding of their behavior under different conditions is helpful for applications such as their use as medical transporters. The transition temperature Tm affects the lipid conformation and the interfacial tension between perfluoroperhydrophenanthrene (PFP) and an aqueous suspension of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC), 1,2-distearoyl-sn-glycero-3-phosphatidylcholine (DSPC), as well as a mixture of these PLs with cholesterol. Interfacial tensions were measured with the Du Noüy ring at quasi-equilibrium; the area per molecule was calculated according to the Gibbsian approach and a time-dependent tension gradient. Results show that the time tε to reach quasi-equilibrium was shorter when the temperature was above Tm, indicating a faster adsorption process (tε,DPPC,36 °C = 48 h, tε,DPPC,48 °C = 24 h) for PL in the liquid crystalline state than in the gel state (T < Tm). In addition, concentration-dependent results of the interfacial tension revealed that above the respective Tm and at all concentrations c > 0.1 mM, the average minimum interfacial tension for DPPC and DSPC (14.1 mN/m and 15.3 mN/m) does not differ significantly between those two lipids. Equilibrium between monolayers and bilayers shows that for T < Tm, surface pressures ∏ ≈ 31 mN/m are reached while for T > Tm, ∏ ≈ 41 mN/m. Mixtures with cholesterol only reach ∏ ≤ 31 mN/m Tm, with no significant difference between the two PLs. The higher interfacial tension of the mixture indicates stabilization of the liposomal conformation in the aqueous phase by the addition of cholesterol. The high diffusion coefficients show that adsorption is mainly based on liposomes.
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Affiliation(s)
- Kirsten Ullmann
- Karlsruhe Institute of Technology (KIT), Department of Mechanical Process Engineering and Mechanics, Straße am Forum 8, 76131 Karlsruhe, Germany;
| | - Lea Fachet
- Independent Researcher, 76131 Karlsruhe, Germany
| | - Hermann Nirschl
- Karlsruhe Institute of Technology (KIT), Department of Mechanical Process Engineering and Mechanics, Straße am Forum 8, 76131 Karlsruhe, Germany;
| | - Gero Leneweit
- Carl Gustav Carus-Institute, Association for the Promotion of Cancer Therapy, Allmendstr. 55, 75223 Niefern-Oeschelbronn, Germany
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17
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Pinigin KV, Akimov SA. The Membrane-Mediated Interaction of Liquid-Ordered Lipid Domains in the Presence of Amphipathic Peptides. MEMBRANES 2023; 13:816. [PMID: 37887988 PMCID: PMC10608175 DOI: 10.3390/membranes13100816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/08/2023] [Accepted: 09/22/2023] [Indexed: 10/28/2023]
Abstract
The lipid membranes of living cells are composed of a large number of lipid types and can undergo phase separation with the formation of nanometer-scale liquid-ordered lipid domains, also called rafts. Raft coalescence, i.e., the fusion of lipid domains, is involved in important cell processes, such as signaling and trafficking. In this work, within the framework of the theory of elasticity of lipid membranes, we explore how amphipathic peptides adsorbed on lipid membranes may affect the domain-domain fusion processes. We show that the elastic deformations of lipid membranes drive amphipathic peptides to the boundary of lipid domains, which leads to an increase in the average energy barrier of the domain-domain fusion, even if the surface concentration of amphipathic peptides is low and the domain boundaries are only partially occupied by the peptides. This inhibition of the fusion of lipid domains may lead to negative side effects of using amphipathic peptides as antimicrobial agents.
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Affiliation(s)
- Konstantin V. Pinigin
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia
| | - Sergey A. Akimov
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia
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18
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Almeida PF. In Search of a Molecular View of Peptide-Lipid Interactions in Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023. [PMID: 37478368 DOI: 10.1021/acs.langmuir.3c00538] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/23/2023]
Abstract
Lipid bilayer membranes are often represented as a continuous nonpolar slab with a certain thickness bounded by two more polar interfaces. Phenomena such as peptide binding to the membrane surface, folding, insertion, translocation, and diffusion are typically interpreted on the basis of this view. In this Perspective, I argue that this membrane representation as a hydrophobic continuum solvent is not adequate to understand peptide-lipid interactions. Lipids are not small compared to membrane-active peptides: their sizes are similar. Therefore, peptide diffusion needs to be understood in terms of free volume, not classical continuum mechanics; peptide solubility or partitioning in membranes cannot be interpreted in terms of hydrophobic mismatch between membrane thickness and peptide length; peptide folding and translocation, often involving cationic peptides, can only be understood if realizing that lipids adapt to the presence of peptides and the membrane may undergo considerable lipid redistribution in the process. In all of those instances, the detailed molecular interactions between the peptide residues and the lipid components are essential to understand the mechanisms involved.
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Affiliation(s)
- Paulo F Almeida
- Department of Chemistry and Biochemistry, University of North Carolina Wilmington, Wilmington, North Carolina 28403, United States
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19
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Nagao M, Seto H. Neutron scattering studies on dynamics of lipid membranes. BIOPHYSICS REVIEWS 2023; 4:021306. [PMID: 38504928 PMCID: PMC10903442 DOI: 10.1063/5.0144544] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 05/01/2023] [Indexed: 03/21/2024]
Abstract
Neutron scattering methods are powerful tools for the study of the structure and dynamics of lipid bilayers in length scales from sub Å to tens to hundreds nm and the time scales from sub ps to μs. These techniques also are nondestructive and, perhaps most importantly, require no additives to label samples. Because the neutron scattering intensities are very different for hydrogen- and deuterium-containing molecules, one can replace the hydrogen atoms in a molecule with deuterium to prepare on demand neutron scattering contrast without significantly altering the physical properties of the samples. Moreover, recent advances in neutron scattering techniques, membrane dynamics theories, analysis tools, and sample preparation technologies allow researchers to study various aspects of lipid bilayer dynamics. In this review, we focus on the dynamics of individual lipids and collective membrane dynamics as well as the dynamics of hydration water.
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Affiliation(s)
| | - Hideki Seto
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan
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20
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Yu T, Flores-Solis D, Eastep GN, Becker S, Zweckstetter M. Phosphatidylserine-dependent structure of synaptogyrin remodels the synaptic vesicle membrane. Nat Struct Mol Biol 2023:10.1038/s41594-023-01004-9. [PMID: 37217654 DOI: 10.1038/s41594-023-01004-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 04/21/2023] [Indexed: 05/24/2023]
Abstract
Synaptic vesicles are small membrane-enclosed organelles that store neurotransmitters at presynaptic terminals. The uniform morphology of synaptic vesicles is important for brain function, because it enables the storage of well-defined amounts of neurotransmitters and thus reliable synaptic transmission. Here, we show that the synaptic vesicle membrane protein synaptogyrin cooperates with the lipid phosphatidylserine to remodel the synaptic vesicle membrane. Using NMR spectroscopy, we determine the high-resolution structure of synaptogyrin and identify specific binding sites for phosphatidylserine. We further show that phosphatidylserine binding changes the transmembrane structure of synaptogyrin and is critical for membrane bending and the formation of small vesicles. Cooperative binding of phosphatidylserine to both a cytoplasmic and intravesicular lysine-arginine cluster in synaptogyrin is required for the formation of small vesicles. Together with other synaptic vesicle proteins, synaptogyrin thus can sculpt the membrane of synaptic vesicles.
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Affiliation(s)
- Taekyung Yu
- German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
| | | | - Gunnar N Eastep
- German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
| | - Stefan Becker
- Department for NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Markus Zweckstetter
- German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany.
- Department for NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
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21
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Potter TD, Haywood N, Teixeira A, Hodges G, Barrett EL, Miller MA. Partitioning into phosphatidylcholine-cholesterol membranes: liposome measurements, coarse-grained simulations, and implications for bioaccumulation. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2023. [PMID: 37158124 DOI: 10.1039/d3em00081h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Membrane-water partitioning is an important physical property for the assessment of bioaccumulation and environmental impact. Here, we advance simulation methodology for predicting the partitioning of small molecules into lipid membranes and compare the computational predictions to experimental measurements in liposomes. As a step towards high-throughput screening, we present an automated mapping and parametrization procedure to produce coarse-grained models compatible with the Martini 3 force field. The methodology is general and can also be used for other applications where coarse-grained simulations are appropriate. This article addresses the effect on membrane-water partitioning of adding cholesterol to POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) membranes. Nine contrasting neutral, zwitterionic and charged solutes are tested. Agreement between experiment and simulation is generally good, with the most challenging cases being permanently charged solutes. For all solutes, partitioning is found to be insensitive to membrane cholesterol concentration up to 25% mole fraction. Hence, for assessment of bioaccumulation into a range of membranes (such as those found in fish), partitioning data measured in pure lipid membranes are still informative.
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Affiliation(s)
- Thomas D Potter
- Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom.
| | - Nicola Haywood
- Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, United Kingdom
| | - Alexandre Teixeira
- Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, United Kingdom
| | - Geoff Hodges
- Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, United Kingdom
| | - Elin L Barrett
- Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, United Kingdom
| | - Mark A Miller
- Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom.
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22
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Sapp K, Aleksanyan M, Kerr K, Dimova R, Sodt A. Kinetic relaxation of giant vesicles validates diffusional softening in a binary lipid mixture. Phys Rev E 2023; 107:054403. [PMID: 37329029 PMCID: PMC10548837 DOI: 10.1103/physreve.107.054403] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 03/15/2023] [Indexed: 06/18/2023]
Abstract
The stiffness of biological membranes determines the work required by cellular machinery to form and dismantle vesicles and other lipidic shapes. Model membrane stiffness can be determined from the equilibrium distribution of giant unilamellar vesicle surface undulations observable by phase contrast microscopy. With two or more components, lateral fluctuations of composition will couple to surface undulations depending on the curvature sensitivity of the constituent lipids. The result is a broader distribution of undulations whose complete relaxation is partially determined by lipid diffusion. In this work, kinetic analysis of the undulations of giant unilamellar vesicles made of phosphatidylcholine-phosphatidylethanolamine mixtures validates the molecular mechanism by which the membrane is made 25% softer than a single-component one. The mechanism is relevant to biological membranes, which have diverse and curvature-sensitive lipids.
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Affiliation(s)
- Kayla Sapp
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, 20892 Maryland, USA
| | - Mina Aleksanyan
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Kaitlyn Kerr
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, 20892 Maryland, USA
| | - Rumiana Dimova
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| | - Alexander Sodt
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, 20892 Maryland, USA
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23
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Mitra S, Coopershlyak M, Li Y, Chandersekhar B, Koenig R, Chen MT, Evans B, Heinrich F, Deslouches B, Tristram-Nagle S. Novel Helical Trp- and Arg-Rich Antimicrobial Peptides Locate Near Membrane Surfaces and Rigidify Lipid Model Membranes. ADVANCED NANOBIOMED RESEARCH 2023; 3:2300013. [PMID: 37476397 PMCID: PMC10358585 DOI: 10.1002/anbr.202300013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/22/2023] Open
Abstract
Antibiotics are losing effectiveness as bacteria become resistant to conventional drugs. To find new alternatives, antimicrobial peptides (AMPs) are rationally designed with different lengths, charges, hydrophobicities (H), and hydrophobic moments (μH), containing only three types of amino acids: arginine, tryptophan, and valine. Six AMPs with low minimum inhibitory concentrations (MICs) and <25% toxicity to mammalian cells are selected for biophysical studies. Their secondary structures are determined using circular dichroism (CD), which finds that the % α-helicity of AMPs depends on composition of the lipid model membranes (LMMs): gram-negative (G(-)) inner membrane (IM) >gram-positive (G(+)) > Euk33 (eukaryotic with 33 mol% cholesterol). The two most effective peptides, E2-35 (16 amino acid [AA] residues) and E2-05 (22 AAs), are predominantly helical in G(-) IM and G(+) LMMs. AMP/membrane interactions such as membrane elasticity, chain order parameter, and location of the peptides in the membrane are investigated by low-angle and wide-angle X-ray diffuse scattering (XDS). It is found that headgroup location correlates with efficacy and toxicity. The membrane bending modulus KC displays nonmonotonic changes due to increasing concentrations of E2-35 and E2-05 in G(-) and G(+) LMMs, suggesting a bacterial killing mechanism where domain formation causes ion and water leakage.
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Affiliation(s)
- Saheli Mitra
- Biological Physics Group Physics Department Carnegie Mellon University Pittsburgh, PA 15213, USA
| | - Mark Coopershlyak
- Biological Physics Group Physics Department Carnegie Mellon University Pittsburgh, PA 15213, USA
| | - Yunshu Li
- Biological Physics Group Physics Department Carnegie Mellon University Pittsburgh, PA 15213, USA
| | - Bhairavi Chandersekhar
- Biological Physics Group Physics Department Carnegie Mellon University Pittsburgh, PA 15213, USA
| | - Rachel Koenig
- Biological Physics Group Physics Department Carnegie Mellon University Pittsburgh, PA 15213, USA
| | - Mei-Tung Chen
- Biological Physics Group Physics Department Carnegie Mellon University Pittsburgh, PA 15213, USA
| | - Brandt Evans
- Biological Physics Group Physics Department Carnegie Mellon University Pittsburgh, PA 15213, USA
| | - Frank Heinrich
- Biological Physics Group Physics Department Carnegie Mellon University Pittsburgh, PA 15213, USA
- Center for Neutron Research National Institute of Standards and Technology Gaithersburg, MD 20878, USA
| | - Berthony Deslouches
- Department of Environmental and Occupational Health University of Pittsburgh Pittsburgh, PA 15261, USA
| | - Stephanie Tristram-Nagle
- Biological Physics Group Physics Department Carnegie Mellon University Pittsburgh, PA 15213, USA
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24
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Gupta R, Ghosh SK. Discerning perturbed assembly of lipids in a model membrane in presence of violacein: Effects of membrane hydrophobicity. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184130. [PMID: 36764473 DOI: 10.1016/j.bbamem.2023.184130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 01/12/2023] [Accepted: 01/27/2023] [Indexed: 02/11/2023]
Abstract
For the lack of effective antibiotics towards antibiotic resisting bacteria, it is required to discover new antibiotics and to understand their antimicrobial mechanism. Violacein is a violet pigment found in several gram-negative bacteria possessing antimicrobial properties to gram-positive bacteria. This present article investigates the insertion ability of this molecule into a model membrane composed of zwitterionic phospholipids. Thermodynamic characterization of lipid monolayers in the presence of violacein was carried out using a single lipid layer formed at air-water interface. The molecule inserts into the layer altering the area occupied by each lipid and the in-plane compressibility of the film. This insertion increases with the hydrophobic chain length of the lipid. The perturbed self-assembly of lipids in a bilayer is quantified using a lipid multilayer system applying the X-ray reflectivity technique. The electron density profile from the reflectivity data shows that the molecule inserts into the fluid phase creating a relatively ordered chain conformation. Further, the insertion into the gel phase is observed to increase with the increased thickness of the hydrophobic core of a bilayer.
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Affiliation(s)
- Ritika Gupta
- Department of Physics, Shiv Nadar Institution of Eminence, NH 91, Tehsil Dadri, G. B. Nagar, Uttar Pradesh 201314, India
| | - Sajal K Ghosh
- Department of Physics, Shiv Nadar Institution of Eminence, NH 91, Tehsil Dadri, G. B. Nagar, Uttar Pradesh 201314, India.
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25
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Wan M, Song J, Yang Y, Gao L, Fang W. A top-down and bottom-up combined strategy for parameterization of coarse-grained force fields for phospholipids. Phys Chem Chem Phys 2023; 25:6757-6767. [PMID: 36789502 DOI: 10.1039/d2cp05384e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Coarse-graining (CG) molecular dynamics (MD) simulations are widely used in interpreting experimental observations and predicting assembly morphology as well as collective behaviour but also face the problem of poor accuracy. A main issue is that cross-termed interactions between different CG beads are inadequately parameterized. This work proposes a novel top-down and bottom-up combined strategy to parameterize both self- and cross-termed interactions of zwitterionic phospholipids in water solution based on a piecewise Morse potential describing nonbonded van der Waals interactions. The self-interacting force parameters were optimized by matching experimental density, heat vapourization, and surface tension in a top-down manner, while the cross-termed interactions were optimized by fitting pseudo properties obtained from atomistic simulations in a bottom-up way, including mixing density, intermolecular energy, and radial mixing coefficient. The transferability of the CG force field (FF) was confirmed by reproducing a variety of structural and thermodynamic properties of lipid membranes in both liquid and gel phases. This FF can well depict vesicle self-assembly and vesicle fusion processes. Matching pseudo properties opens a new way to develop CG FF with increased accuracy and transferability.
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Affiliation(s)
- Mingwei Wan
- Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China. .,Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, 19 Xin-Jie-Kou-Wai Street, Beijing 100875, China.
| | - Junjie Song
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, 19 Xin-Jie-Kou-Wai Street, Beijing 100875, China.
| | - Ying Yang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, 19 Xin-Jie-Kou-Wai Street, Beijing 100875, China.
| | - Lianghui Gao
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, 19 Xin-Jie-Kou-Wai Street, Beijing 100875, China.
| | - Weihai Fang
- Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China. .,Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, 19 Xin-Jie-Kou-Wai Street, Beijing 100875, China.
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26
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Marlow B, Kuenze G, Meiler J, Koehler Leman J. Docking cholesterol to integral membrane proteins with Rosetta. PLoS Comput Biol 2023; 19:e1010947. [PMID: 36972273 PMCID: PMC10042369 DOI: 10.1371/journal.pcbi.1010947] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/14/2023] [Indexed: 03/29/2023] Open
Abstract
Lipid molecules such as cholesterol interact with the surface of integral membrane proteins (IMP) in a mode different from drug-like molecules in a protein binding pocket. These differences are due to the lipid molecule's shape, the membrane's hydrophobic environment, and the lipid's orientation in the membrane. We can use the recent increase in experimental structures in complex with cholesterol to understand protein-cholesterol interactions. We developed the RosettaCholesterol protocol consisting of (1) a prediction phase using an energy grid to sample and score native-like binding poses and (2) a specificity filter to calculate the likelihood that a cholesterol interaction site may be specific. We used a multi-pronged benchmark (self-dock, flip-dock, cross-dock, and global-dock) of protein-cholesterol complexes to validate our method. RosettaCholesterol improved sampling and scoring of native poses over the standard RosettaLigand baseline method in 91% of cases and performs better regardless of benchmark complexity. On the β2AR, our method found one likely-specific site, which is described in the literature. The RosettaCholesterol protocol quantifies cholesterol binding site specificity. Our approach provides a starting point for high-throughput modeling and prediction of cholesterol binding sites for further experimental validation.
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Affiliation(s)
- Brennica Marlow
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Georg Kuenze
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
- Institute for Drug Discovery, Leipzig University Medical School, Leipzig, Germany
| | - Jens Meiler
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
- Institute for Drug Discovery, Leipzig University Medical School, Leipzig, Germany
| | - Julia Koehler Leman
- Center for Computational Biology, Flatiron Institute, Simons Foundation, New York, New York, United States of America
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27
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Ivanova N, Chamati H. The Effect of Cholesterol in SOPC Lipid Bilayers at Low Temperatures. MEMBRANES 2023; 13:275. [PMID: 36984662 PMCID: PMC10058253 DOI: 10.3390/membranes13030275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 06/18/2023]
Abstract
We study the behavior of lipid bilayers composed of SOPC (1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine) with different concentrations of cholesterol, ranging from 10 mol% to 50 mol% at 273 K. To this end, we carry out extensive atomistic molecular dynamic simulations with the aid of the Slipid force field aiming at computing basic bilayer parameters, as well as thermodynamic properties and structural characteristics. The obtained results are compared to available relevant experimental data and the outcome of atomistic simulations performed on bilayers composed of analogous phospholipids. Our results show a good quantitative, as well as qualitative, agreement with the main trends associated with the concentration increase in cholesterol. Moreover, it comes out that a change in the behavior of the bilayer is brought about at a concentration of about 30 mol% cholesterol. At this very concentration, some of the bilayer properties are found to exhibit a saturation and a significant long-range ordering of the lipid molecules in the membrane shows up.
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Affiliation(s)
- Nikoleta Ivanova
- Department of Physical Chemistry, University of Chemical Technology and Metallurgy, 8 Kliment Ohridski Blvd., 1756 Sofia, Bulgaria
- Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria
| | - Hassan Chamati
- Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria
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28
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Kambar N, Leal C. Microfluidic synthesis of multilayered lipid-polymer hybrid nanoparticles for the formulation of low solubility drugs. SOFT MATTER 2023; 19:1596-1605. [PMID: 36752169 PMCID: PMC10080587 DOI: 10.1039/d2sm01443b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Hybrid phospholipid/block copolymer membranes where polymers and lipids are molecularly mixed or phase-separated into polymer-rich and lipid-rich domains are promising drug delivery materials. Harnessing the chemical diversity of polymers and the biocompatability of lipids is a compelling approach to design the next generation of drug carriers. Here, we report on the development of a microfluidics-based strategy analogous to produce lipid nanoparticles (LNPs) for the nanomanufacturing of multilayered hybrid nanoparticles (HNPs). Using X-ray scattering, Cryo-electron, and polarized microscopy we show that phosphatidylcholine (PC) and PBD-b-PEO (poly(butadiene-block-ethylene oxide)) hybrid membranes can be nanomanufactured by microfluidics into HNPs with dense and multilayered cores which are ideal carriers of low-solubility drugs of the Biopharmaceutical Classification System (BCS) II and IV such as antimalarial DSM265 and Paclitaxel, respectively.
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Affiliation(s)
- Nurila Kambar
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois, USA.
| | - Cecília Leal
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois, USA.
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29
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Cholesterol stabilization of phospholipid vesicles against bile-induced solubilization. Chem Phys Lipids 2023; 252:105289. [PMID: 36813145 DOI: 10.1016/j.chemphyslip.2023.105289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/03/2022] [Accepted: 02/17/2023] [Indexed: 02/22/2023]
Abstract
Sphingomyelin (SM) and cholesterol complex to form functional liquid-ordered (Lo) domains. It has been suggested that the detergent resistance of these domains plays a key role during gastrointestinal digestion of the milk fat globule membrane (MFGM), which is rich in both SM and cholesterol. Small-angle X-ray scattering was employed to determine the structural alterations that occur when milk sphingomyelin (MSM)/cholesterol, egg sphingomyelin (ESM)/cholesterol, soy phosphatidylcholine (SPC)/cholesterol, and milk fat globule membrane (MFGM) phospholipid/cholesterol model bilayer systems were incubated with bovine bile under physiological conditions. The persistence of diffraction peaks was indicative of multilamellar vesicles of MSM with cholesterol concentrations > 20 % mol, and also for ESM with or without cholesterol. The complexation of ESM with cholesterol is therefore capable of inhibiting the resulting vesicles from disruption by bile at lower cholesterol concentrations than MSM/cholesterol. After subtraction of background scattering by large aggregates in the bile, a Guinier fitting was used to determine changes in the radii of gyration (Rgs) over time for the biliary mixed micelles after mixing the vesicle dispersions with bile. Swelling of the micelles by phospholipid solubilization from vesicles was a function of cholesterol concentration, with less swelling of the micelles occurring as the cholesterol concentration was increased. With 40% mol cholesterol, the Rgs of the bile micelles mixed with MSM/cholesterol, ESM/cholesterol, and MFGM phospholipid/cholesterol were equal to the control (PIPES buffer + bovine bile), indicating negligible swelling of the biliary mixed micelles.
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30
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Doole FT, Gupta S, Kumarage T, Ashkar R, Brown MF. Biophysics of Membrane Stiffening by Cholesterol and Phosphatidylinositol 4,5-bisphosphate (PIP2). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1422:61-85. [PMID: 36988877 DOI: 10.1007/978-3-031-21547-6_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Cell membranes regulate a wide range of phenomena that are implicated in key cellular functions. Cholesterol, a critical component of eukaryotic cell membranes, is responsible for cellular organization, membrane elasticity, and other critical physicochemical parameters. Besides cholesterol, other lipid components such as phosphatidylinositol 4,5-bisphosphate (PIP2) are found in minor concentrations in cell membranes yet can also play a major regulatory role in various cell functions. In this chapter, we describe how solid-state deuterium nuclear magnetic resonance (2H NMR) spectroscopy together with neutron spin-echo (NSE) spectroscopy can inform synergetic changes to lipid molecular packing due to cholesterol and PIP2 that modulate the bending rigidity of lipid membranes. Fundamental structure-property relations of molecular self-assembly are illuminated and point toward a length and time-scale dependence of cell membrane mechanics, with significant implications for biological activity and membrane lipid-protein interactions.
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Affiliation(s)
- Fathima T Doole
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | - Sudipta Gupta
- Department of Physics and Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA, USA
| | - Teshani Kumarage
- Department of Physics and Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA, USA
| | - Rana Ashkar
- Department of Physics and Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA, USA.
| | - Michael F Brown
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA.
- Department of Physics, University of Arizona, Tucson, AZ, USA.
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31
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Park S, Kim HK. Development of skin-permeable flexible liposome using ergosterol esters containing unsaturated fatty acids. Chem Phys Lipids 2023; 250:105270. [PMID: 36493880 DOI: 10.1016/j.chemphyslip.2022.105270] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/21/2022] [Accepted: 12/04/2022] [Indexed: 12/12/2022]
Abstract
Ergosterol (Ergo) and cholesterol contribute to performances of liposomes by increasing membrane packing density and physical stability. However, as these sterols can reduce membrane flexibility, they can lower skin permeability of liposomes. We synthesized ergosterol ester (Ergo-Est) containing unsaturated fatty acid different from Ergo in size and physical properties. In this work, we investigated effects of Ergo-Est and Ergo on physical properties of liposomes. We incorporated Ergo, Ergo-oleate (EO18:1), Ergo-linoleate (EL18:2), and Ergo-linolenate (ELn18:3) into the liposomal membrane of egg phosphatidylcholine and soybean lecithin. Ergo-Est did not reduce membrane fluidity as much as Ergo. Nevertheless, Ergo-Est increased membrane packing density and physical stability of liposomes. EL18:2 and ELn18:3 almost maintained membrane flexibility and skin permeability of liposomes, while Ergo significantly reduced them. Skin permeation test demonstrated that EL18:2 and ELn18:3 liposomes permeated to the dermis, whereas Ergo liposome mostly remained in the stratum corneum. This is the first report to show that EL18:2 and ELn18:3 can be efficient sterol compounds for flexible liposome formulation.
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Affiliation(s)
- Sehyeon Park
- Division of Biotechnology, The Catholic University of Korea, Bucheon 420-743, Republic of Korea
| | - Hyung Kwoun Kim
- Division of Biotechnology, The Catholic University of Korea, Bucheon 420-743, Republic of Korea.
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32
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Park H, Sut TN, Yoon BK, Zhdanov VP, Cho NJ, Jackman JA. Unraveling How Cholesterol Affects Multivalency-Induced Membrane Deformation of Sub-100 nm Lipid Vesicles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:15950-15959. [PMID: 36515977 DOI: 10.1021/acs.langmuir.2c02252] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Cholesterol plays a critical role in modulating the lipid membrane properties of biological and biomimetic systems and recent attention has focused on its role in the functions of sub-100 nm lipid vesicles and lipid nanoparticles. These functions often rely on multivalent ligand-receptor interactions involving membrane attachment and dynamic shape transformations while the extent to which cholesterol can influence such interaction processes is largely unknown. To address this question, herein, we investigated the attachment of sub-100 nm lipid vesicles containing varying cholesterol fractions (0-45 mol %) to membrane-mimicking supported lipid bilayer (SLB) platforms. Biotinylated lipids and streptavidin proteins were used as model ligands and receptors, respectively, while the localized surface plasmon resonance sensing technique was employed to track vesicle attachment kinetics in combination with analytical modeling of vesicle shape changes. Across various conditions mimicking low and high multivalency, our findings revealed that cholesterol-containing vesicles could bind to receptor-functionalized membranes but underwent appreciably less multivalency-induced shape deformation than vesicles without cholesterol, which can be explained by a cholesterol-mediated increase in membrane bending rigidity. Interestingly, the extent of vesicle deformation that occurred in response to increasingly strong multivalent interactions was less pronounced for vesicles with greater cholesterol fraction. The latter trend was rationalized by taking into account the strong dependence of the membrane bending energy on the area of the vesicle-SLB contact region and such insights can aid the engineering of membrane-enveloped nanoparticles with tailored biophysical properties.
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Affiliation(s)
- Hyeonjin Park
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Drive, Singapore 637553, Singapore
| | | | - Bo Kyeong Yoon
- School of Healthcare and Biomedical Engineering, Chonnam National University, Yeosu 59626, Republic of Korea
| | - Vladimir P Zhdanov
- Division of Nano and Biophysics, Department of Physics, Chalmers University of Technology, Gothenburg 41296, Sweden
- Boreskov Institute of Catalysis, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Nam-Joon Cho
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Drive, Singapore 637553, Singapore
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33
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Kondrashov OV, Akimov SA. A Mechanism of Double-Membrane Vesicle Formation from Liquid-Ordered/Liquid-Disordered Phase Separated Spherical Membrane. MEMBRANES 2022; 13:25. [PMID: 36676832 PMCID: PMC9862188 DOI: 10.3390/membranes13010025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 12/12/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
Genome replication of coronaviruses takes place in specific cellular compartments, in so-called double-membrane vesicles (DMVs), formed from the endoplasmic reticulum (ER). An intensive production of DMVs is induced by non-structural viral proteins. Here, we proposed a possible mechanism of the DMV formation from ER-derived spherical vesicles where liquid-ordered and liquid-disordered lipid phases coexist. These vesicles are supposed to divide into two homogeneous liquid-ordered and liquid-disordered vesicles. The formation of two spherical vesicles constituting DMV requires a mechanical work to be performed. We considered the excess energy of the boundary between the coexisting lipid phases as the main driving force behind the division of the initial vesicle. Explicitly accounting for the energy of elastic deformations and the interphase boundary energy, we analyzed a range of physical parameters where the DMV formation is possible. We concluded that this process can principally take place in a very narrow range of system parameters. The most probable diameter of DMVs formed according to the proposed mechanism appeared to be approximately 220 nm, in an agreement with the average diameter of DMVs observed in vivo. Our consideration predicts the DMV size to be strongly limited from above. The developed analysis can be utilized for the production of DMVs in model systems.
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34
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Porras-Gómez M, Kim H, Dronadula MT, Kambar N, Metellus CJB, Aluru NR, van der Zande A, Leal C. Multiscale compression-induced restructuring of stacked lipid bilayers: From buckling delamination to molecular packing. PLoS One 2022; 17:e0275079. [PMID: 36490254 PMCID: PMC9733850 DOI: 10.1371/journal.pone.0275079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 11/23/2022] [Indexed: 12/13/2022] Open
Abstract
Lipid membranes in nature adapt and reconfigure to changes in composition, temperature, humidity, and mechanics. For instance, the oscillating mechanical forces on lung cells and alveoli influence membrane synthesis and structure during breathing. However, despite advances in the understanding of lipid membrane phase behavior and mechanics of tissue, there is a critical knowledge gap regarding the response of lipid membranes to micromechanical forces. Most studies of lipid membrane mechanics use supported lipid bilayer systems missing the structural complexity of pulmonary lipids in alveolar membranes comprising multi-bilayer interconnected stacks. Here, we elucidate the collective response of the major component of pulmonary lipids to strain in the form of multi-bilayer stacks supported on flexible elastomer substrates. We utilize X-ray diffraction, scanning probe microscopy, confocal microscopy, and molecular dynamics simulation to show that lipid multilayered films both in gel and fluid states evolve structurally and mechanically in response to compression at multiple length scales. Specifically, compression leads to increased disorder of lipid alkyl chains comparable to the effect of cholesterol on gel phases as a direct result of the formation of nanoscale undulations in the lipid multilayers, also inducing buckling delamination and enhancing multi-bilayer alignment. We propose this cooperative short- and long-range reconfiguration of lipid multilayered films under compression constitutes a mechanism to accommodate stress and substrate topography. Our work raises fundamental insights regarding the adaptability of complex lipid membranes to mechanical stimuli. This is critical to several technologies requiring mechanically reconfigurable surfaces such as the development of electronic devices interfacing biological materials.
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Affiliation(s)
- Marilyn Porras-Gómez
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America
| | - Hyunchul Kim
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America
| | - Mohan Teja Dronadula
- Walker Department of Mechanical Engineering, Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, Texas, United States of America
| | - Nurila Kambar
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America
| | - Christopher J. B. Metellus
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America
| | - Narayana R. Aluru
- Walker Department of Mechanical Engineering, Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, Texas, United States of America
| | - Arend van der Zande
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America,* E-mail: (AZ); (CL)
| | - Cecília Leal
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America,* E-mail: (AZ); (CL)
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35
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Flegler VJ, Rasmussen T, Böttcher B. How Functional Lipids Affect the Structure and Gating of Mechanosensitive MscS-like Channels. Int J Mol Sci 2022; 23:ijms232315071. [PMID: 36499396 PMCID: PMC9739000 DOI: 10.3390/ijms232315071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/21/2022] [Accepted: 11/23/2022] [Indexed: 12/04/2022] Open
Abstract
The ability to cope with and adapt to changes in the environment is essential for all organisms. Osmotic pressure is a universal threat when environmental changes result in an imbalance of osmolytes inside and outside the cell which causes a deviation from the normal turgor. Cells have developed a potent system to deal with this stress in the form of mechanosensitive ion channels. Channel opening releases solutes from the cell and relieves the stress immediately. In bacteria, these channels directly sense the increased membrane tension caused by the enhanced turgor levels upon hypoosmotic shock. The mechanosensitive channel of small conductance, MscS, from Escherichia coli is one of the most extensively studied examples of mechanically stimulated channels. Different conformational states of this channel were obtained in various detergents and membrane mimetics, highlighting an intimate connection between the channel and its lipidic environment. Associated lipids occupy distinct locations and determine the conformational states of MscS. Not all these features are preserved in the larger MscS-like homologues. Recent structures of homologues from bacteria and plants identify common features and differences. This review discusses the current structural and functional models for MscS opening, as well as the influence of certain membrane characteristics on gating.
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36
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Molugu TR, Thurmond RL, Alam TM, Trouard TP, Brown MF. Phospholipid headgroups govern area per lipid and emergent elastic properties of bilayers. Biophys J 2022; 121:4205-4220. [PMID: 36088534 PMCID: PMC9674990 DOI: 10.1016/j.bpj.2022.09.005] [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: 03/15/2022] [Revised: 08/10/2022] [Accepted: 09/06/2022] [Indexed: 11/24/2022] Open
Abstract
Phospholipid bilayers are liquid-crystalline materials whose intermolecular interactions at mesoscopic length scales have key roles in the emergence of membrane physical properties. Here we investigated the combined effects of phospholipid polar headgroups and acyl chains on biophysical functions of membranes with solid-state 2H NMR spectroscopy. We compared the structural and dynamic properties of phosphatidylethanolamine and phosphatidylcholine with perdeuterated acyl chains in the solid-ordered (so) and liquid-disordered (ld) phases. Our analysis of spectral lineshapes of 1,2-diperdeuteriopalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE-d62) and 1,2-diperdeuteriopalmitoyl-sn-glycero-3-phosphocholine (DPPC-d62) in the so (gel) phase indicated an all-trans rotating chain structure for both lipids. Greater segmental order parameters (SCD) were observed in the ld (liquid-crystalline) phase for DPPE-d62 than for DPPC-d62 membranes, while their mixtures had intermediate values irrespective of the deuterated lipid type. Our results suggest the SCD profiles of the acyl chains are governed by methylation of the headgroups and are averaged over the entire system. Variations in the acyl chain molecular dynamics were further investigated by spin-lattice (R1Z) and quadrupolar-order relaxation (R1Q) measurements. The two acyl-perdeuterated lipids showed distinct differences in relaxation behavior as a function of the order parameter. The R1Z rates had a square-law dependence on SCD, implying collective mesoscopic dynamics, with a higher bending rigidity for DPPE-d62 than for DPPC-d62 lipids. Remodeling of lipid average and dynamic properties by methylation of the headgroups thus provides a mechanism to control the actions of peptides and proteins in biomembranes.
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Affiliation(s)
- Trivikram R Molugu
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona
| | | | - Todd M Alam
- Department of Organic Materials Science, Sandia National Laboratories, Albuquerque, New Mexico
| | - Theodore P Trouard
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona
| | - Michael F Brown
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona; Department of Physics, University of Arizona, Tucson, Arizona.
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37
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Doole FT, Kumarage T, Ashkar R, Brown MF. Cholesterol Stiffening of Lipid Membranes. J Membr Biol 2022; 255:385-405. [PMID: 36219221 PMCID: PMC9552730 DOI: 10.1007/s00232-022-00263-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 08/05/2022] [Indexed: 11/30/2022]
Abstract
Biomembrane order, dynamics, and other essential physicochemical parameters are controlled by cholesterol, a major component of mammalian cell membranes. Although cholesterol is well known to exhibit a condensing effect on fluid lipid membranes, the extent of stiffening that occurs with different degrees of lipid acyl chain unsaturation remains an enigma. In this review, we show that cholesterol locally increases the bending rigidity of both unsaturated and saturated lipid membranes, suggesting there may be a length-scale dependence of the bending modulus. We review our published data that address the origin of the mechanical effects of cholesterol on unsaturated and polyunsaturated lipid membranes and their role in biomembrane functions. Through a combination of solid-state deuterium NMR spectroscopy and neutron spin-echo spectroscopy, we show that changes in molecular packing cause the universal effects of cholesterol on the membrane bending rigidity. Our findings have broad implications for the role of cholesterol in lipid–protein interactions as well as raft-like mixtures, drug delivery applications, and the effects of antimicrobial peptides on lipid membranes.
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Affiliation(s)
- Fathima T Doole
- Deaprtment of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85712, USA
| | - Teshani Kumarage
- Department of Physics, Virginia Tech, Blacksburg, VA, 24061, USA.,Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Rana Ashkar
- Department of Physics, Virginia Tech, Blacksburg, VA, 24061, USA. .,Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA, 24061, USA.
| | - Michael F Brown
- Deaprtment of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85712, USA. .,Department of Physics, University of Arizona, Tucson, AZ, 85712, USA.
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38
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Akter S, Karal MAS, Hasan S, Ahamed MK, Ahmed M, Ahammed S. Effects of cholesterol on the anionic magnetite nanoparticle-induced deformation and poration of giant lipid vesicles. RSC Adv 2022; 12:28283-28294. [PMID: 36320506 PMCID: PMC9531538 DOI: 10.1039/d2ra03199j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 09/28/2022] [Indexed: 06/16/2023] Open
Abstract
We have investigated the effects of cholesterol on the deformation and poration of giant unilamellar vesicles (GUVs) induced by anionic magnetite nanoparticles (NPs). Negatively charged lipid, neutral lipid, and cholesterol were used to prepare the charged GUVs (surface charge density of membranes - 0.16 C m-2), while only neutral lipid and cholesterol were used to prepare the neutral GUVs. Cholesterol content varied from 0 to 40 mole% for preparing the biologically relevant membranes. The degree of deformation has been characterized by compactness, the value of which remains at 1.0 for spherical GUVs. The value of compactness increases with time for both membranes, but this increase depends on cholesterol content. The average compactness decreases with cholesterol content, and at 60 min, the values are 1.280 ± 0.002 and 1.131 ± 0.010 for 0 and 40 mole% cholesterol containing charged GUVs. The average compactness is relatively lower for neutral GUVs for the corresponding cholesterol. Membrane poration has been investigated by the leakage of calcein, which indicates a two-state transition model. The fraction of deformation is higher for charged GUVs than for neutral ones, while the fraction of poration shows the opposite result. Both the fractions decrease with cholesterol content.
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Affiliation(s)
- Salma Akter
- Department of Physics, Bangladesh University of Engineering and Technology Dhaka 1000 Bangladesh +880-2-58613046 +880-2-9665613
| | - Mohammad Abu Sayem Karal
- Department of Physics, Bangladesh University of Engineering and Technology Dhaka 1000 Bangladesh +880-2-58613046 +880-2-9665613
| | - Sharif Hasan
- Department of Physics, Bangladesh University of Engineering and Technology Dhaka 1000 Bangladesh +880-2-58613046 +880-2-9665613
| | - Md Kabir Ahamed
- Department of Physics, Bangladesh University of Engineering and Technology Dhaka 1000 Bangladesh +880-2-58613046 +880-2-9665613
- Radiation, Transport and Waste Safety Division, Bangladesh Atomic Energy Regulatory Authority Agargaon Dhaka 1207 Bangladesh
| | - Marzuk Ahmed
- Department of Physics, Bangladesh University of Engineering and Technology Dhaka 1000 Bangladesh +880-2-58613046 +880-2-9665613
| | - Shareef Ahammed
- Department of Physics, Bangladesh University of Engineering and Technology Dhaka 1000 Bangladesh +880-2-58613046 +880-2-9665613
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Himbert S, Rheinstädter MC. Structural and mechanical properties of the red blood cell’s cytoplasmic membrane seen through the lens of biophysics. Front Physiol 2022; 13:953257. [PMID: 36171967 PMCID: PMC9510598 DOI: 10.3389/fphys.2022.953257] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 08/15/2022] [Indexed: 11/27/2022] Open
Abstract
Red blood cells (RBCs) are the most abundant cell type in the human body and critical suppliers of oxygen. The cells are characterized by a simple structure with no internal organelles. Their two-layered outer shell is composed of a cytoplasmic membrane (RBCcm) tethered to a spectrin cytoskeleton allowing the cell to be both flexible yet resistant against shear stress. These mechanical properties are intrinsically linked to the molecular composition and organization of their shell. The cytoplasmic membrane is expected to dominate the elastic behavior on small, nanometer length scales, which are most relevant for cellular processes that take place between the fibrils of the cytoskeleton. Several pathologies have been linked to structural and compositional changes within the RBCcm and the cell’s mechanical properties. We review current findings in terms of RBC lipidomics, lipid organization and elastic properties with a focus on biophysical techniques, such as X-ray and neutron scattering, and Molecular Dynamics simulations, and their biological relevance. In our current understanding, the RBCcm’s structure is patchy, with nanometer sized liquid ordered and disordered lipid, and peptide domains. At the same time, it is surprisingly soft, with bending rigidities κ of 2–4 kBT. This is in strong contrast to the current belief that a high concentration of cholesterol results in stiff membranes. This extreme softness is likely the result of an interaction between polyunsaturated lipids and cholesterol, which may also occur in other biological membranes. There is strong evidence in the literature that there is no length scale dependence of κ of whole RBCs.
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Affiliation(s)
- Sebastian Himbert
- Department of Physics and Astronomy, McMaster University, Hamilton, ON, Canada
- Origins Institute, McMaster University, Hamilton, ON, Canada
- *Correspondence: Sebastian Himbert, ; Maikel C. Rheinstädter,
| | - Maikel C. Rheinstädter
- Department of Physics and Astronomy, McMaster University, Hamilton, ON, Canada
- Origins Institute, McMaster University, Hamilton, ON, Canada
- *Correspondence: Sebastian Himbert, ; Maikel C. Rheinstädter,
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40
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Lechner BD, Smith P, McGill B, Marshall S, Trick JL, Chumakov AP, Winlove CP, Konovalov OV, Lorenz CD, Petrov PG. The Effects of Cholesterol Oxidation on Erythrocyte Plasma Membranes: A Monolayer Study. MEMBRANES 2022; 12:828. [PMID: 36135847 PMCID: PMC9506283 DOI: 10.3390/membranes12090828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/17/2022] [Accepted: 08/18/2022] [Indexed: 06/16/2023]
Abstract
Cholesterol plays a key role in the molecular and mesoscopic organisation of lipid membranes and it is expected that changes in its molecular structure (e.g., through environmental factors such as oxidative stress) may affect adversely membrane properties and function. In this study, we present evidence that oxidation of cholesterol has significant effects on the mechanical properties, molecular and mesoscopic organisation and lipid-sterol interactions in condensed monolayers composed of the main species found in the inner leaflet of the erythrocyte membrane. Using a combination of experimental methods (static area compressibility, surface dilatational rheology, fluorescence microscopy, and surface sensitive X-ray techniques) and atomistic molecular dynamics simulations, we show that oxidation of cholesterol to 7-ketocholesterol leads to stiffening of the monolayer (under both static and dynamic conditions), significant changes in the monolayer microdomain organisation, disruption in the van der Waals, electrostatic and hydrophobic interactions between the sterol and the other lipid species, and the lipid membrane hydration. Surface sensitive X-ray techniques reveal that, whilst the molecular packing mode is not significantly affected by cholesterol oxidation in these condensed phases, there are subtle changes in membrane thickness and a significant decrease in the coherence length in monolayers containing 7-ketocholesterol.
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Affiliation(s)
- Bob-Dan Lechner
- Department of of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
| | - Paul Smith
- Department of Physics, King’s College London, The Strand, London WC2R 2LS, UK
| | - Beth McGill
- Department of of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
| | - Skye Marshall
- Department of of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
| | - Jemma L. Trick
- Department of Physics, King’s College London, The Strand, London WC2R 2LS, UK
| | - Andrei P. Chumakov
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Charles Peter Winlove
- Department of of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
| | - Oleg V. Konovalov
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Christian D. Lorenz
- Department of Physics, King’s College London, The Strand, London WC2R 2LS, UK
| | - Peter G. Petrov
- Department of of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
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The bending rigidity of the red blood cell cytoplasmic membrane. PLoS One 2022; 17:e0269619. [PMID: 35913930 PMCID: PMC9342732 DOI: 10.1371/journal.pone.0269619] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 05/24/2022] [Indexed: 11/19/2022] Open
Abstract
An important mechanical property of cells is the membrane bending modulus, κ. In the case of red blood cells (RBCs) there is a composite membrane consisting of a cytoplasmic membrane and an underlying spectrin network. Literature values of κ are puzzling, as they are reported over a wide range, from 5 kBT to 230 kBT. To disentangle the contribution of the cytoplasmic membrane from the spectrin network, we investigated the bending of red blood cell cytoplasmic membranes (RBCcm) in the absence of spectrin and adenosine triphosphate (ATP). We used a combination of X-ray diffuse scattering (XDS), neutron spin-echo (NSE) spectrometry and Molecular Dynamics (MD) simulations. Our results indicate values of κ of order 4 kBT to 6 kBT, relatively small compared to literature values for most single component lipid bilayers. We suggest two ways this relative softness might confer biological advantage.
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Anthony AA, Sahin O, Yapici MK, Rogers D, Honerkamp-Smith AR. Systematic measurements of interleaflet friction in supported bilayers. Biophys J 2022; 121:2981-2993. [PMID: 35754183 PMCID: PMC9388387 DOI: 10.1016/j.bpj.2022.06.023] [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: 03/15/2022] [Revised: 05/23/2022] [Accepted: 06/22/2022] [Indexed: 11/20/2022] Open
Abstract
When lipid membranes curve or are subjected to strong shear forces, the two apposed leaflets of the bilayer slide past each other. The drag that one leaflet creates on the other is quantified by the coefficient of interleaflet friction, b. Existing measurements of this coefficient range over several orders of magnitude, so we used a recently developed microfluidic technique to measure it systematically in supported lipid membranes. Fluid shear stress was used to force the top leaflet of a supported membrane to slide over the stationary lower leaflet. Here, we show that this technique yields a reproducible measurement of the friction coefficient and is sensitive enough to detect differences in friction between membranes made from saturated and unsaturated lipids. Adding cholesterol to saturated and unsaturated membranes increased interleaflet friction significantly. We also discovered that fluid shear stress can reversibly induce gel phase in supported lipid bilayers that are close to the gel-transition temperature.
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Panahi M, Rad VF, Sasan S, Jamali R, Moradi AR, Darudi A. Detection of intralayer alignment in multicomponent lipids by dynamic speckle pattern analysis. JOURNAL OF BIOPHOTONICS 2022; 15:e202200034. [PMID: 35460181 DOI: 10.1002/jbio.202200034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 04/08/2022] [Accepted: 04/19/2022] [Indexed: 06/14/2023]
Abstract
Multicomponent mixtures of bilayer lipids, thanks to the coexistence of liquid-crystalline phases in their structures, may be used in the development of functional membranes. In such membranes interlayer ordering distributes across membrane lamellae, resulting in long-range alignment of phase-separated domains. In this paper, we explore the dynamics of this phenomenon by laser speckle pattern analysis. We show that cholesterol content decreases the activity, and the rate of the domains size development is related to the change of physical roughness of the multicomponent lipid mixture. Our results are in agreement with the previous experimental reports. However, our experimental procedure is an easy-to-implement and effective methodology.
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Affiliation(s)
- Majid Panahi
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan, Iran
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran
| | - Vahideh Farzam Rad
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran
| | - Shiva Sasan
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan, Iran
| | - Ramin Jamali
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran
| | - Ali-Reza Moradi
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran
- School of Nano Science, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran
| | - Ahmad Darudi
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan, Iran
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Hossain MI, Karal MAS, Kamruzzaman M, Syed IM, Hasan S, Ahamed MK. Effects of hydrocarbon chain on the vesicle size distribution, kinetics of average size, bending modulus, and elastic modulus of lipid membranes. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2022; 45:55. [PMID: 35748998 DOI: 10.1140/epje/s10189-022-00209-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Accepted: 06/06/2022] [Indexed: 06/15/2023]
Abstract
The effects of the hydrocarbon chain of lipids on the size distribution of giant unilamellar vesicles (GUVs), kinetics of average size, bending modulus, and elastic modulus of membranes have been investigated. 1,2-dioleoyl-sn-glycero-3-phosphocholine (18:1 (Δ9-Cis) PC (DOPC)), 1,2-dipalmitoleoyl-sn-glycero-3-phosphocholine (16:1 (Δ9-Cis) PC), and 1,2-ditridecanoyl-sn-glycerol-3-phosphocholine (13:0 PC (DTPC)) lipids were considered. The number of hydrocarbons in a chain of the corresponding lipid was 18, 16, and 13. GUVs were prepared using the natural swelling method under incubation times of 20, 40, 60, 90, 120, and 180 min. The size distribution of vesicles was fitted using the lognormal distribution. The average sizes of DOPC, 16:1 (Δ9-Cis) PC, and DTPC-GUVs increased with the incubation time until 120 min, and then remained steady at 16.7 ± 0.2, 15.2 ± 0.4 and 12.0 ± 0.3 µm for the corresponding lipids. The average size at equilibrium state increased with the number of hydrocarbons. The incubation time-dependent average size was fitted with an exponential growth equation, and then the kinetic constants of 0.028 ± 0.004, 0.036 ± 0.007, and 0.083 ± 0.009 min-1 for DOPC, 16:1 (Δ9-Cis) PC, and DTPC-GUVs, respectively, were obtained. The equilibrium size distribution was fitted by the theoretical equation, and the bending modulus for DOPC, 16:1 (Δ9-Cis) PC, and DTPC membranes were 19.5 ± 0.2, 18.5 ± 0.1 and 14.3 ± 0.1 kBT, respectively. The bending modulus increased with the number of hydrocarbons. The elastic modulus of these membranes was 261 mN/m with a 4% fluctuation. The correlation between the average size and the square root of the bending modulus was supported by theoretical analysis.
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Affiliation(s)
- Md Imran Hossain
- Department of Physics, University of Dhaka, Dhaka, 1000, Bangladesh
| | - Mohammad Abu Sayem Karal
- Department of Physics, Bangladesh University of Engineering and Technology, Dhaka, 1000, Bangladesh.
| | - Md Kamruzzaman
- Department of Physics, University of Dhaka, Dhaka, 1000, Bangladesh
| | - Ishtiaque M Syed
- Department of Physics, University of Dhaka, Dhaka, 1000, Bangladesh
| | - Sharif Hasan
- Department of Physics, Bangladesh University of Engineering and Technology, Dhaka, 1000, Bangladesh
| | - Md Kabir Ahamed
- Department of Physics, Bangladesh University of Engineering and Technology, Dhaka, 1000, Bangladesh
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45
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Ramezanpour M, Tieleman DP. Computational Insights into the Role of Cholesterol in Inverted Hexagonal Phase Stabilization and Endosomal Drug Release. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:7462-7471. [PMID: 35675506 PMCID: PMC9220946 DOI: 10.1021/acs.langmuir.2c00430] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 05/25/2022] [Indexed: 06/01/2023]
Abstract
Cholesterol is a major component of many lipid-based drug delivery systems, including cationic lipid nanoparticles. Despite its critical role in the drug release stage, the underlying molecular mechanism by which cholesterol assists in endosomal escape remains unclear. An efficient drug release from the endosome requires endosomal disruption. This disruption is believed to involve a lamellar-to-inverted hexagonal (Lα-HII) phase transition upon fusion of the lipid nanoparticle with the endosomal membrane. We used molecular dynamics simulations to study the structural properties of HII systems composed of an anionic lipid distearoyl phosphatidylserine (DSPS), an ionizable cationic lipid (KC2H), and cholesterol for several hydration levels and molar ratios. This system corresponds to the lipid mixtures in the hypothesized HII structure formed upon fusion and is of interest for the rational design of ionizable cationic lipids, including KC2, for an optimal drug release. Simulations suggest a geometry- and symmetry-driven lipid sorting and cholesterol-DSPS co-location around the water cores. Cholesterol preferentially co-locates with negatively charged saturated DSPS lipids at interstitial angles. The observed cholesterol-DSPS co-location results in an overall increase in the DSPS acyl chains' order parameters, which we propose to assist in stabilizing the HII phase by stretching the DSPS acyl chains for filling the voids formed by three adjacent lipid tubules. Furthermore, a systematic increase in the cholesterol concentration increased the lattice plane spacing and the water core radius but decreased the undulations along the lipid tubule axis. We propose that cholesterol and the degree of saturation/polyunsaturation of the lipid acyl chains, and not the lipid charge, are the main contributors in facilitating the Lα-HII phase transition and stabilizing/destabilizing the formed HII phase, whereas the positive charge of the ionizable cationic lipid promotes the LNP-endosomal membrane adhesion and assists in initiating the fusion process at the local contact area. We also propose that the effect of cholesterol on the HII structure and curvature is the main underlying reason for the well-documented HII stabilization and destabilization at low and high molar concentrations of cholesterol, respectively.
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46
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Sack S, Zucker B, Yecheskel Y, Zucker I. The role of size, charge, and cholesterol of cell membrane models in interactions with graphene oxide. JOURNAL OF HAZARDOUS MATERIALS 2022; 432:128661. [PMID: 35305415 DOI: 10.1016/j.jhazmat.2022.128661] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 01/28/2022] [Accepted: 03/08/2022] [Indexed: 06/14/2023]
Abstract
The growing in manufacturing and applications of graphene oxide (GO), a two-dimensional nanomaterial, highlights the need for a better understanding of its environmental impact and toxicity. This work investigates the interaction of GO with cell membrane models as an indication for GO's potential harmfulness. A wide range of biologically-relevant membrane parameters (size, charge and, cholesterol content) and simple optical techniques were used to evaluate the outcome of interactions of vesicular cell membrane models with GO. Loss of membrane integrity was found to be positively correlated with electrostatic attraction and negatively correlated with cholesterol content. The size of vesicle-GO aggregates increased as a function of initial vesicle size, while cholesterol content was found to have a negligible effect on aggregation. Interestingly, charged vesicles reduced vesicle-GO aggregate size either by electrostatic repulsion of negatively charge vesicles or by GO folding following attachment of positively charge vesicles. Overall, by examining how key biologically-relevant parameters of membrane models affect interactions with GO, we have augmented the understanding of the potential threats of GO towards biological cell and to the environment.
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Affiliation(s)
- Shaanan Sack
- School of Mechanical Engineering, Tel Aviv University, 69978, Israel
| | - Ben Zucker
- Sackler Faculty of Medicine, Tel Aviv University, 69978, Israel
| | - Yinon Yecheskel
- School of Mechanical Engineering, Tel Aviv University, 69978, Israel; The Porter School of Environmental and Earth Sciences, Tel Aviv University, 69978 Israel
| | - Ines Zucker
- School of Mechanical Engineering, Tel Aviv University, 69978, Israel; The Porter School of Environmental and Earth Sciences, Tel Aviv University, 69978 Israel.
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47
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Modeling and Simulation of Lipid Membranes. MEMBRANES 2022; 12:membranes12060549. [PMID: 35736255 PMCID: PMC9228261 DOI: 10.3390/membranes12060549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 05/23/2022] [Accepted: 05/23/2022] [Indexed: 02/05/2023]
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48
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Zaytseva YV, Zaytseva IV, Surovtsev NV. Conformational state diagram of DOPC/DPPC d62/cholesterol mixtures. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183869. [PMID: 35063400 DOI: 10.1016/j.bbamem.2022.183869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 01/09/2022] [Accepted: 01/12/2022] [Indexed: 06/14/2023]
Abstract
Raman spectra of aqueous suspensions of vesicles composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), deuterated 1,2-dipalmitoyl-d62-sn-glycero-3-phosphocholine (DPPCd62), and cholesterol (Chol) were studied at room temperature to determine the conformational states of the phospholipid hydrocarbon chains. Deuteration of DPPCd62 allowed us to characterize the conformational states of DOPC and DPPCd62 independently. The parameters of Raman peaks, which are sensitive to the conformational order, were studied in a wide range of compositions. It was found that the DOPC molecules are conformationally disordered for all compositions. The conformational state of the DPPCd62 molecules changes with composition. Their conformational state is influenced by cholesterol-induced partial disordering and DOPC solvation, transforming the DPPC molecules into the disordered state. The conformational state diagram from the Raman experiment was compared with outcomes from the differential scanning calorimetry (DSC) experiment. The Raman spectra also revealed that the DPPC molecules coexist in the disordered and all-trans ordered states for the DOPC/DPPCd62/Chol mixtures except for the pure liquid-disordered phase.
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Affiliation(s)
- Yu V Zaytseva
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - I V Zaytseva
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - N V Surovtsev
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia.
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Hu Z, Marti J. In Silico Drug Design of Benzothiadiazine Derivatives Interacting with Phospholipid Cell Membranes. MEMBRANES 2022; 12:membranes12030331. [PMID: 35323806 PMCID: PMC8949146 DOI: 10.3390/membranes12030331] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/09/2022] [Accepted: 03/15/2022] [Indexed: 12/21/2022]
Abstract
The use of drugs derived from benzothiadiazine, a bicyclic heterocyclic benzene derivative, has become a widespread treatment for diseases such as hypertension, low blood sugar or the human immunodeficiency virus, among others. In this work we have investigated the interactions of benzothiadiazine and four of its derivatives designed in silico with model zwitterionic cell membranes formed by dioleoylphosphatidylcholine, 1,2-dioleoyl-sn-glycero-3-phosphoserine and cholesterol at the liquid–crystal phase inside aqueous potassium chloride solution. We have elucidated the local structure of benzothiadiazine by means of microsecond molecular dynamics simulations of systems including a benzothiadiazine molecule or one of its derivatives. Such derivatives were obtained by the substitution of a single hydrogen site of benzothiadiazine by two different classes of chemical groups, one of them electron-donating groups (methyl and ethyl) and another one by electron-accepting groups (fluorine and trifluoromethyl). Our data have revealed that benzothiadiazine derivatives have a strong affinity to stay at the cell membrane interface although their solvation characteristics can vary significantly—they can be fully solvated by water in short periods of time or continuously attached to specific lipid sites during intervals of 10–70 ns. Furthermore, benzothiadiazines are able to bind lipids and cholesterol chains by means of single and double hydrogen-bonds of characteristic lengths between 1.6 and 2.1 Å.
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Lu H, Martí J. Predicting the conformational variability of oncogenic GTP-bound G12D mutated KRas-4B proteins at zwitterionic model cell membranes. NANOSCALE 2022; 14:3148-3158. [PMID: 35142321 DOI: 10.1039/d1nr07622a] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
KRas proteins are the largest family of mutated Ras isoforms, participating in a wide variety of cancers. Due to their importance, large effort is being carried out on drug development by small-molecule inhibitors. However, understanding protein conformational variability remains a challenge in drug discovery. In the case of the Ras family, their multiple conformational states can affect the binding of potential drug inhibitors. To overcome this challenge, we propose a computational framework based on combined all-atom Molecular Dynamics and Metadynamics simulations in order to accurately access conformational variants of the target protein. We tested the methodology using a G12D mutated GTP bound oncogenic KRas-4B protein located at the interface of a DOPC/DOPS/cholesterol model anionic cell membrane. Two main orientations of KRas-4B at the anionic membrane have been determined. The corresponding torsional angles are taken as reliable reaction coordinates so that free-energy landscapes are obtained by well-tempered metadynamics simulations, revealing local and global minima of the free-energy hypersurface and unveiling reactive paths of the system between the two preferential orientations. We have observed that GTP-binding to KRas-4B has huge influence on the stabilisation of the protein and it can potentially help to open Switch I/II druggable pockets, lowering energy barriers between stable states and resulting in cumulative conformers of KRas-4B. This may highlight new opportunities for targeting the unique meta-stable states through the design of new efficient drugs.
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Affiliation(s)
- Huixia Lu
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China.
| | - Jordi Martí
- Department of Physics, Polytechnical University of Catalonia-Barcelona Tech, B5-209 Northern Campus, Jordi Girona 1-3, 08034 Barcelona, Catalonia, Spain.
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