1
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Li Y, Liu F, Che J, Zhang Y, Yin T, Gou J, Tang X, Wang Y, He H. Sodium glycocholate liposome encapsulated semaglutide increases oral bioavailability by promoting intestinal absorption. Int J Pharm 2024; 665:124669. [PMID: 39244070 DOI: 10.1016/j.ijpharm.2024.124669] [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: 05/23/2024] [Revised: 08/15/2024] [Accepted: 09/03/2024] [Indexed: 09/09/2024]
Abstract
The aim of this study was to prepare sodium glycocholate liposomes (SGC-Lip) encapsulating semaglutide (Sml) to improve oral bioavailability and better exert hypoglycemic effect. In this paper, SGC-Lip was prepared by reverse-phase evaporation method with particle size around 140 nm, potential around -27 mV, rounded morphology and better stability. The hypoglycemic and intestinal uptake effects of SGC-Lip and cholesterol-containing liposomes (CH-Lip) were comparatively investigated in rats, and the oral safety of SGC-Lip was examined by cytotoxicity assay. The results indicate that SGC-Lip can achieve a hypoglycemic effect of 40% of the initial value within 12 hours, and the AAC0-12h is approximately six times that of CH-Lip without sodium glycocholate. The results of the cytotoxicity tests indicate that SGC-Lip has good oral safety. SGC-Lip enhances the absorption of semaglutide in the small intestinal villi via an apical sodium-dependent bile acid transporter (ASBT)-mediated pathway with the highest penetration at the ileal site. In summary, the oral bioavailability of semaglutide can be improved by encapsulating semaglutide in SGC-Lip and utilizing the stabilizing and permeation-promoting effects of SGC on liposomes.
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Affiliation(s)
- Yehan Li
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Fei Liu
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Jiajing Che
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Yu Zhang
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Tian Yin
- School of Functional Food and Wine, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Jingxin Gou
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Xing Tang
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Yanjiao Wang
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Haibing He
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, China.
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2
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Odenkirk MT, Zhang G, Marty MT. Do Nanodisc Assembly Conditions Affect Natural Lipid Uptake? JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:2006-2015. [PMID: 37524089 PMCID: PMC10528108 DOI: 10.1021/jasms.3c00170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Lipids play critical roles in modulating membrane protein structure, interactions, and activity. Nanodiscs provide a tunable membrane mimetic that can model these endogenous protein-lipid interactions in a nanoscale lipid bilayer. However, most studies of membrane proteins with nanodiscs use simple synthetic lipids that lack the headgroup and fatty acyl diversity of natural extracts. Prior research has successfully used natural lipid extracts in nanodiscs that more accurately mimic natural environments, but it is not clear how nanodisc assembly may bias the incorporated lipid profiles. Here, we applied lipidomics to investigate how nanodisc assembly conditions affect the profile of natural lipids in nanodiscs. Specifically, we tested the effects of assembly temperature, nanodisc size, and lipidome extract complexity. Globally, our analysis demonstrates that the lipids profiles are largely unaffected by nanodisc assembly conditions. However, a few notable changes emerged within individual lipids and lipid classes, such as a differential incorporation of cardiolipin and phosphatidylglycerol lipids from the E. coli polar lipid extract at different temperatures. Conversely, some classes of brain lipids were affected by nanodisc size at higher temperatures. Collectively, these data enable the application of nanodiscs to study protein-lipid interactions in complex lipid environments.
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Affiliation(s)
- Melanie T. Odenkirk
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ
- Bio5 Institute, University of Arizona, Tucson, AZ
| | - Guozhi Zhang
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ
| | - Michael T. Marty
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ
- Bio5 Institute, University of Arizona, Tucson, AZ
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3
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Paez-Perez M, Dent MR, Brooks NJ, Kuimova MK. Viscosity-Sensitive Membrane Dyes as Tools To Estimate the Crystalline Structure of Lipid Bilayers. Anal Chem 2023; 95:12006-12014. [PMID: 37526607 PMCID: PMC10433245 DOI: 10.1021/acs.analchem.3c01747] [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: 04/22/2023] [Accepted: 07/12/2023] [Indexed: 08/02/2023]
Abstract
Lipid membranes are crucial for cellular integrity and regulation, and tight control of their structural and mechanical properties is vital to ensure that they function properly. Fluorescent probes sensitive to the membrane's microenvironment are useful for investigating lipid membrane properties; however, there is currently a lack of quantitative correlation between the exact parameters of lipid organization and a readout from these dyes. Here, we investigate this relationship for "molecular rotors", or microviscosity sensors, by simultaneously measuring their fluorescence lifetime to determine the membrane viscosity, while using X-ray diffraction to determine the membrane's structural properties. Our results reveal a phase-dependent correlation between the membrane's structural parameters and mechanical properties measured by a BODIPY-based molecular rotor, giving excellent predictive power for the structural descriptors of the lipid bilayer. We also demonstrate that differences in membrane thickness between different lipid phases are not a prerequisite for the formation of lipid microdomains and that this requirement can be disrupted by the presence of line-active molecules. Our results underpin the use of membrane-sensitive dyes as reporters of the structure of lipid membranes.
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Affiliation(s)
- Miguel Paez-Perez
- MSRH, Department of Chemistry, Imperial College London, Wood Lane, London W12 0BZ, U.K.
| | - Michael R. Dent
- MSRH, Department of Chemistry, Imperial College London, Wood Lane, London W12 0BZ, U.K.
| | - Nicholas J. Brooks
- MSRH, Department of Chemistry, Imperial College London, Wood Lane, London W12 0BZ, U.K.
| | - Marina K. Kuimova
- MSRH, Department of Chemistry, Imperial College London, Wood Lane, London W12 0BZ, U.K.
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4
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Sharma KD, Heberle FA, Waxham MN. Visualizing lipid membrane structure with cryo-EM: past, present, and future. Emerg Top Life Sci 2023; 7:55-65. [PMID: 36606590 PMCID: PMC10355340 DOI: 10.1042/etls20220090] [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: 11/15/2022] [Revised: 12/14/2022] [Accepted: 12/20/2022] [Indexed: 01/07/2023]
Abstract
The development of electron cryomicroscopy (cryo-EM) has evolved immensely in the last several decades and is now well-established in the analysis of protein structure both in isolation and in their cellular context. This review focuses on the history and application of cryo-EM to the analysis of membrane architecture. Parallels between the levels of organization of protein structure are useful in organizing the discussion of the unique parameters that influence membrane structure and function. Importantly, the timescales of lipid motion in bilayers with respect to the timescales of sample vitrification is discussed and reveals what types of membrane structure can be reliably extracted in cryo-EM images of vitrified samples. Appreciating these limitations, a review of the application of cryo-EM to examine the lateral organization of ordered and disordered domains in reconstituted and biologically derived membranes is provided. Finally, a brief outlook for further development and application of cryo-EM to the analysis of membrane architecture is provided.
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Affiliation(s)
- Karan D. Sharma
- Department of Chemistry, University of Tennessee, Knoxville, TN
| | | | - M. Neal Waxham
- Department of Neurobiology and Anatomy, University of Texas Health Science Center, Houston, TX
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5
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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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6
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Zykova VA, Surovtsev NV. Brillouin Spectroscopy of Binary Phospholipid-Cholesterol Bilayers. APPLIED SPECTROSCOPY 2022; 76:1206-1215. [PMID: 35712869 DOI: 10.1177/00037028221111147] [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] [Indexed: 06/15/2023]
Abstract
Multicomponent lipid bilayers are used as models for searching the origin of spatial heterogeneities in biomembranes called lipid rafts, implying the coexistence of domains of different phases and compositions within the lipid bilayer. The spatial organization of multicomponent lipid bilayers on a scale of a hundred nanometers remains unknown. Brillouin spectroscopy providing information about the acoustic phonons with the wavelength of several hundred nanometers has an unexplored potential for this problem. Here, we applied Brillouin spectroscopy for three binary bilayers composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-palmitoyl-sn-glycero-3-phosphocholine (DPPC), and cholesterol. The Brillouin experiment for the oriented planar multibilayers was realized for two scattering geometries involving phonons for the lateral and normal directions of the propagation. The DPPC-DOPC mixtures known for the coexistence of the solid-ordered and liquid-disordered phases had bimodal Brillouin peaks, revealing the phase domains with sizes more than a hundred nanometers. Analysis of the Brillouin data for the binary mixtures concluded that the lateral phonons are preferable for testing the lateral homogeneity of the bilayers, while the phonons spreading across the bilayers are sensitive to the layered packing at the mesoscopic scale.
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Affiliation(s)
- Valeria A Zykova
- 104673Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk, Russia
| | - Nikolay V Surovtsev
- 104673Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk, Russia
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7
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Manrique-Moreno M, Jemioła-Rzemińska M, Múnera-Jaramillo J, López GD, Suesca E, Leidy C, Strzałka K. Staphylococcus aureus Carotenoids Modulate the Thermotropic Phase Behavior of Model Systems That Mimic Its Membrane Composition. MEMBRANES 2022; 12:945. [PMID: 36295704 PMCID: PMC9612337 DOI: 10.3390/membranes12100945] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 09/23/2022] [Accepted: 09/25/2022] [Indexed: 06/16/2023]
Abstract
Staphylococcus aureus (S. aureus) is a pathogenic gram-positive bacterium that normally resides in the skin and nose of the human body. It is subject to fluctuations in environmental conditions that may affect the integrity of the membrane. S. aureus produces carotenoids, which act as antioxidants. However, these carotenoids have also been implicated in modulating the biophysical properties of the membrane. Here, we investigate how carotenoids modulate the thermotropic phase behavior of model systems that mimic the phospholipid composition of S. aureus. We found that carotenoids depress the main phase transition of DMPG and CL, indicating that they strongly affect cooperativity of membrane lipids in their gel phase. In addition, carotenoids modulate the phase behavior of mixtures of DMPG and CL, indicating that they may play a role in modulation of lipid domain formation in S. aureus membranes.
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Affiliation(s)
- Marcela Manrique-Moreno
- Chemistry Institute, Faculty of Exact and Natural Sciences, University of Antioquia, Medellin 050010, Colombia
| | - Małgorzata Jemioła-Rzemińska
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-392 Krakow, Poland
- Malopolska Centre of Biotechnology, Jagiellonian University, 30-392 Krakow, Poland
| | - Jessica Múnera-Jaramillo
- Chemistry Institute, Faculty of Exact and Natural Sciences, University of Antioquia, Medellin 050010, Colombia
| | - Gerson-Dirceu López
- Laboratory of Advanced Analytical Techniques in Natural Products (LATNAP), Chemistry Department, Universidad de los Andes, Bogotá 111711, Colombia
- Biophysics Group, Department of Physics, Universidad de los Andes, Bogotá 111711, Colombia
| | - Elizabeth Suesca
- Biophysics Group, Department of Physics, Universidad de los Andes, Bogotá 111711, Colombia
| | - Chad Leidy
- Biophysics Group, Department of Physics, Universidad de los Andes, Bogotá 111711, Colombia
| | - Kazimierz Strzałka
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-392 Krakow, Poland
- Malopolska Centre of Biotechnology, Jagiellonian University, 30-392 Krakow, Poland
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8
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Utterström J, Barriga HMG, Holme MN, Selegård R, Stevens MM, Aili D. Peptide-Folding Triggered Phase Separation and Lipid Membrane Destabilization in Cholesterol-Rich Lipid Vesicles. Bioconjug Chem 2022; 33:736-746. [PMID: 35362952 PMCID: PMC9026255 DOI: 10.1021/acs.bioconjchem.2c00115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Liposome-based drug
delivery systems are widely used to improve
drug pharmacokinetics but can suffer from slow and unspecific release
of encapsulated drugs. Membrane-active peptides, based on sequences
derived or inspired from antimicrobial peptides (AMPs), could offer
means to trigger and control the release. Cholesterol is used in most
liposomal drug delivery systems (DDS) to improve the stability of
the formulation, but the activity of AMPs on cholesterol-rich membranes
tends to be very low, complicating peptide-triggered release strategies.
Here, we show a de novo designed AMP-mimetic peptide that efficiently
triggers content release from cholesterol-containing lipid vesicles
when covalently conjugated to headgroup-functionalized lipids. Binding
to vesicles induces peptide folding and triggers a lipid phase separation,
which in the presence of cholesterol results in high local peptide
concentrations at the lipid bilayer surface and rapid content release.
We anticipate that these results will facilitate the development of
peptide-based strategies for controlling and triggering drug release
from liposomal drug delivery systems.
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Affiliation(s)
- Johanna Utterström
- Laboratory of Molecular Materials, Division of Biophysics and Bioengineering, Department of Physics, Chemistry and Biology, SE-581 83 Linköping, Sweden
| | - Hanna M G Barriga
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Margaret N Holme
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Robert Selegård
- Laboratory of Molecular Materials, Division of Biophysics and Bioengineering, Department of Physics, Chemistry and Biology, SE-581 83 Linköping, Sweden
| | - Molly M Stevens
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden.,Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, U.K
| | - Daniel Aili
- Laboratory of Molecular Materials, Division of Biophysics and Bioengineering, Department of Physics, Chemistry and Biology, SE-581 83 Linköping, Sweden
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9
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Cohen R, Mukai C, Nelson JL, Zenilman SS, Sosnicki DM, Travis AJ. A genetically targeted sensor reveals spatial and temporal dynamics of acrosomal calcium and sperm acrosome exocytosis. J Biol Chem 2022; 298:101868. [PMID: 35346690 PMCID: PMC9046242 DOI: 10.1016/j.jbc.2022.101868] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 03/19/2022] [Accepted: 03/23/2022] [Indexed: 01/16/2023] Open
Abstract
Secretion of the acrosome, a single vesicle located rostrally in the head of a mammalian sperm, through a process known as "acrosome exocytosis" (AE), is essential for fertilization. However, the mechanisms leading to and regulating this complex process are controversial. In particular, poor understanding of Ca2+ dynamics between sperm subcellular compartments and regulation of membrane fusion mechanisms have led to competing models of AE. Here, we developed a transgenic mouse expressing an Acrosome-targeted Sensor for Exocytosis (AcroSensE) to investigate the spatial and temporal Ca2+ dynamics in AE in live sperm. AcroSensE combines a genetically encoded Ca2+ indicator (GCaMP) fused with an mCherry indicator to spatiotemporally resolve acrosomal Ca2+ rise (ACR) and membrane fusion events, enabling real-time study of AE. We found that ACR is dependent on extracellular Ca2+ and that ACR precedes AE. In addition, we show that there are intermediate steps in ACR and that AE correlates better with the ACR rate rather than absolute Ca2+ amount. Finally, we demonstrate that ACR and membrane fusion progression kinetics and spatial patterns differ with different stimuli and that sites of initiation of ACR and sites of membrane fusion do not always correspond. These findings support a model involving functionally redundant pathways that enable a highly regulated, multistep AE in heterogeneous sperm populations, unlike the previously proposed "acrosome reaction" model.
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Affiliation(s)
- Roy Cohen
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA.
| | - Chinatsu Mukai
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Jacquelyn L Nelson
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Shoshana S Zenilman
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Danielle M Sosnicki
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Alexander J Travis
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA; Department of Public and Ecosystem Health, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
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10
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Schachter I, Paananen RO, Fábián B, Jurkiewicz P, Javanainen M. The Two Faces of the Liquid Ordered Phase. J Phys Chem Lett 2022; 13:1307-1313. [PMID: 35104407 PMCID: PMC8842317 DOI: 10.1021/acs.jpclett.1c03712] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Coexisting liquid ordered (Lo) and liquid disordered (Ld) lipid phases in synthetic and plasma membrane-derived vesicles are commonly used to model the heterogeneity of biological membranes, including their putative ordered rafts. However, raft-associated proteins exclusively partition to the Ld and not the Lo phase in these model systems. We believe that the difference stems from the different microscopic structures of the lipid rafts at physiological temperature and the Lo phase studied at room temperature. To probe this structural diversity across temperatures, we performed atomistic molecular dynamics simulations, differential scanning calorimetry, and fluorescence spectroscopy on Lo phase membranes. Our results suggest that raft-associated proteins are excluded from the Lo phase at room temperature due to the presence of a stiff, hexagonally packed lipid structure. This structure melts upon heating, which could lead to the preferential solvation of proteins by order-preferring lipids. This structural transition is manifested as a subtle crossover in membrane properties; yet, both temperature regimes still fulfill the definition of the Lo phase. We postulate that in the compositionally complex plasma membrane and in vesicles derived therefrom, both molecular structures can be present depending on the local lipid composition. These structural differences must be taken into account when using synthetic or plasma membrane-derived vesicles as a model for cellular membrane heterogeneity below the physiological temperature.
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Affiliation(s)
- Itay Schachter
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 542/2, CZ-16000 Prague 6, Czech Republic
- Institute
of Chemistry, the Fritz Haber Research Center, and the Harvey M. Kruger
Center for Nanoscience & Nanotechnology, The Hebrew University, Jerusalem 9190401, Israel
| | - Riku O. Paananen
- Department
of Chemistry, FI-00014 University of Helsinki, Helsinki, Finland
- Department
of Ophthalmology, FI-00014 University of
Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Balázs Fábián
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 542/2, CZ-16000 Prague 6, Czech Republic
| | - Piotr Jurkiewicz
- J.
Heyrovský Institute of Physical Chemistry of the Czech Academy
of Sciences, Dolejškova
2155/3, CZ-18223 Prague 8, Czech Republic
- E-mail:
| | - Matti Javanainen
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 542/2, CZ-16000 Prague 6, Czech Republic
- Institute
of Biotechnology, FI-00014 University of
Helsinki, Helsinki, Finland
- E-mail:
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11
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Hitaishi P, Mandal P, Ghosh SK. Partitioning of a Hybrid Lipid in Domains of Saturated and Unsaturated Lipids in a Model Cellular Membrane. ACS OMEGA 2021; 6:34546-34554. [PMID: 34963939 PMCID: PMC8697375 DOI: 10.1021/acsomega.1c04835] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/30/2021] [Indexed: 06/14/2023]
Abstract
The cellular membranes are composed of hundreds of components such as lipids, proteins, and sterols that are chemically and physically distinct from each other. The lipid-lipid and lipid-protein interactions form domains in this membrane, which play vital roles in membrane physiology. The hybrid lipids (HLs) with one saturated and one unsaturated chain can control the shape and size of these domains, ensuring the thermodynamic stability of a membrane. In this study, the thermodynamics of mixing of a HL and its structural effects on the phase separated domains in a model membrane composed of a saturated and an unsaturated lipid have been investigated. The HL is observed to mix into an unsaturated lipid reducing the Gibbs free energy, whereas the mixing is unfavorable in a saturated lipid. The presence of an HL in an unsaturated lipid tends to increase its area fraction, which is reflected in the enhanced correlation length across the bilayers in a multilayered sample. There is a feeble effect on the domain structure of the saturated lipid due to the presence of the HLs at the phase boundary. This study concludes that the HLs preferentially participate in the unsaturated lipid regions compared to that of a saturated lipid.
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12
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Li J, Chang C, Zhai J, Yang Y, Yu H. Ascorbyl palmitate effects on the stability of curcumin-loaded soybean phosphatidylcholine liposomes. FOOD BIOSCI 2021. [DOI: 10.1016/j.fbio.2021.100923] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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13
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Fritz JR, Loney RW, Hall SB, Tristram-Nagle S. Suppression of L α/L β Phase Coexistence in the Lipids of Pulmonary Surfactant. Biophys J 2020; 120:243-253. [PMID: 33347885 DOI: 10.1016/j.bpj.2020.12.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/17/2020] [Accepted: 12/07/2020] [Indexed: 12/23/2022] Open
Abstract
To determine how different constituents of pulmonary surfactant affect its phase behavior, we measured wide-angle x-ray scattering (WAXS) from oriented bilayers. Samples contained the nonpolar and phospholipids (N&PL) obtained from calf lung surfactant extract (CLSE), which also contains the hydrophobic surfactant proteins SP-B and SP-C. Mixtures with different ratios of N&PL and CLSE provided the same set of lipids with different amounts of the proteins. At 37°C, N&PL by itself forms coexisting Lα and Lβ phases. In the Lβ structure, the acyl chains of the phospholipids occupy an ordered array that has melted by 40°C. This behavior suggests that the Lβ composition is dominated by dipalmitoyl phosphatidylcholine (DPPC), which is the most prevalent component of CLSE. The Lβ chains, however, lack the tilt of the Lβ' phase formed by pure DPPC. At 40°C, WAXS also detects an additional diffracted intensity, the location of which suggests a correlation among the phospholipid headgroups. The mixed samples of N&PL with CLSE show that increasing amounts of the proteins disrupt both the Lβ phase and the headgroup correlation. With physiological levels of the proteins in CLSE, both types of order are absent. These results with bilayers at physiological temperatures indicate that the hydrophobic surfactant proteins disrupt the ordered structures that have long been considered essential for the ability of pulmonary surfactant to sustain low surface tensions. They agree with prior fluorescence micrographic results from monomolecular films of CLSE, suggesting that at physiological temperatures, any ordered phase is likely to be absent or occupy a minimal interfacial area.
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Affiliation(s)
- Jonathan R Fritz
- Biological Physics Group, Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Ryan W Loney
- Pulmonary and Critical Care Medicine, Oregon Health & Science University, Portland, Oregon
| | - Stephen B Hall
- Pulmonary and Critical Care Medicine, Oregon Health & Science University, Portland, Oregon.
| | - Stephanie Tristram-Nagle
- Biological Physics Group, Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania.
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14
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Redondo-Morata L, Losada-Pérez P, Giannotti MI. Lipid bilayers: Phase behavior and nanomechanics. CURRENT TOPICS IN MEMBRANES 2020; 86:1-55. [PMID: 33837691 DOI: 10.1016/bs.ctm.2020.08.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Lipid membranes are involved in many physiological processes like recognition, signaling, fusion or remodeling of the cell membrane or some of its internal compartments. Within the cell, they are the ultimate barrier, while maintaining the fluidity or flexibility required for a myriad of processes, including membrane protein assembly. The physical properties of in vitro model membranes as model cell membranes have been extensively studied with a variety of techniques, from classical thermodynamics to advanced modern microscopies. Here we review the nanomechanics of solid-supported lipid membranes with a focus in their phase behavior. Relevant information obtained by quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM) as complementary techniques in the nano/mesoscale interface is presented. Membrane morphological and mechanical characterization will be discussed in the framework of its phase behavior, phase transitions and coexistence, in simple and complex models, and upon the presence of cholesterol.
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Affiliation(s)
- Lorena Redondo-Morata
- Center for Infection and Immunity of Lille, INSERM U1019, CNRS UMR 8204, Lille, France
| | - Patricia Losada-Pérez
- Experimental Soft Matter and Thermal Physics (EST) Group, Department of Physics, Université Libre de Bruxelles, Brussels, Belgium
| | - Marina Inés Giannotti
- Biomedical Research Networking Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain; Institut de Bioenginyeria de Catalunya (IBEC), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain; Departament de Ciència de Materials i Química Física, Universitat de Barcelona, Barcelona, Spain.
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15
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Vega M, Lurio L, Lal J, Karapetrova EA, Gaillard ER. Structure of supported DPPC/cholesterol bilayers studied via X-ray reflectivity. Phys Chem Chem Phys 2020; 22:19089-19099. [PMID: 32807995 DOI: 10.1039/d0cp01834a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electron density profile of bilayers of DPPC/cholesterol mixtures supported on semiconductor grade silicon substrates were studied with the objective of determining how the proximity of a solid interface modifies the phase diagram of mixed bilayers. The bilayers were studied in situ immersed in water via synchrotron X-ray reflectivity (XRR). Measurements were performed as a function of temperature through the main phase transition and cholesterol mole fractions up to 40%. Analysis of XRR yields the bilayer thickness, roughness and leaflet asymmetry. We find that the structure of the pure DPPC bilayers in the gel phase is in agreement with previous X-ray measurements of supported bilayers deposited via vesicle fusion and multilamellar vesicles but show more clearly defined features than measurements made on films formed using Langmuir-Blodget Langmuir-Shaffer (LB) deposition. Examination of bilayer thickness vs. temperature shows that the melting temperature for supported bilayers is shifted upwards by approximately 4 °C relative to multilamellar vesicles and that the melting temperature decreases with increasing cholesterol content up to 20%. For pure DPPC bilayers the leaflets melt in two stages with the distal leaflet melting first. For cholesterol concentrations of 10% and 20% there is no clear indication of separate melting. For 33% and 40% cholesterol content no clear transition is seen in the bilayer thickness, but an abrupt change in roughness indicates possible microdomain formation in the 40% cholesterol sample.
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Affiliation(s)
- Michael Vega
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115, USA.
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16
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Kafle A, Akamatsu M, Bhadani A, Sakai K, Kaise C, Kaneko T, Sakai H. Phase Behavior of the Bilayers Containing Hydrogenated Soy Lecithin and β-Sitosteryl Sulfate. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:6025-6032. [PMID: 32393038 DOI: 10.1021/acs.langmuir.0c00472] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The phase behaviors of systems containing saturated phosphatidylcholine (PC) and plant steroids can be important for designing new alternative delivery methods. In our previous studies, we found that even a small amount of β-sitosteryl sulfate (PSO4) significantly affects the phase behavior, hydration properties, and liposomal properties of pure saturated phosphatidylcholines [Kafle, A.; Colloids Surf., B 2018, 161, 59-66; Kafle, A.; J. Oleo Sci. 2018, 67 (12), 1511-1519]. In the current paper, we are reporting the phase behavior of a more complex system consisting of hydrogenated soy lecithin (HLC), which is useful as a carrier in drug delivery systems or in cosmetics, and PSO4. HLC, which is composed of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidic acid (PA), and lysophosphatidylcholine (LPC), demonstrated a versatile phase behavior. The PC component of HLC was found to separate from the PE and PA components as a result of nonideal mixing. At room temperature, these two domains represented two distinct gel phases denoted Lβ1 and Lβ2. The Lβ1 phase selectively underwent transition into the liquid crystalline phase (Lα) at a lower temperature than Lβ2. Upon addition of PSO4, at room temperature, the PC fraction gradually converted into the liquid-ordered (Lo) phase, while the (PE + PA) fraction remained unaffected. When heated above 60 °C, the whole material converted into the liquid crystalline phase. The observed fluidizing effect of PSO4 on HLC can find applications in preparing vehicles for moisture or drugs in cosmetic and pharmaceutical formulations.
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Affiliation(s)
- Ananda Kafle
- Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
| | - Masaaki Akamatsu
- Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
| | - Avinash Bhadani
- Research Institute for Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
| | - Kenichi Sakai
- Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
- Research Institute for Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
| | - Chihiro Kaise
- Research Institute for Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
- L. V. M. C. Inc., Kamagome-7-14-3, Toshima-ku, Tokyo 170-0003, Japan
| | - Teruhisa Kaneko
- Research Institute for Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
- L. V. M. C. Inc., Kamagome-7-14-3, Toshima-ku, Tokyo 170-0003, Japan
| | - Hideki Sakai
- Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
- Research Institute for Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
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17
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Membrane Adhesion via Glycolipids Occurs for Abundant Saccharide Chemistries. Biophys J 2020; 118:1602-1611. [PMID: 32097623 DOI: 10.1016/j.bpj.2020.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/29/2020] [Accepted: 02/05/2020] [Indexed: 01/03/2023] Open
Abstract
Membrane-bound oligosaccharides with specific chemistries are known to promote tight adhesion between adjacent membranes via the formation of weak saccharide bonds. However, in the literature, one can find scattered evidence that other, more abundant saccharide chemistries exhibit similar behavior. Here, the influence of various glycolipids on the interaction between adjacent membranes is systematically investigated with the help of small- and wide-angle x-ray scattering and complementary neutron diffraction experiments. Added electrostatic repulsion between the membrane surfaces is used to identify the formation of saccharide bonds and to challenge their stability against tensile stress. Some of the saccharide headgroup types investigated are able to bind adjacent membranes together, but this ability has no significant influence on the membrane bending rigidity. Our results indicate that glycolipid-mediated membrane adhesion is a highly abundant phenomenon and therefore potentially of great biological relevance.
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18
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A comparative study of the effects of 7β-hydroxycholesterol, 25-hydroxycholesterol, and cholesterol on the structural and thermal phase behavior of multilamellar dipalmitoylphosphatidylcholine bilayer vesicles. Chem Phys Lipids 2020; 227:104872. [DOI: 10.1016/j.chemphyslip.2020.104872] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 12/23/2019] [Accepted: 01/03/2020] [Indexed: 01/11/2023]
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19
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Gu RX, Baoukina S, Tieleman DP. Phase Separation in Atomistic Simulations of Model Membranes. J Am Chem Soc 2020; 142:2844-2856. [DOI: 10.1021/jacs.9b11057] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Ruo-Xu Gu
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive, N.W., Calgary, Alberta T2N 1N4, Canada
| | - Svetlana Baoukina
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive, N.W., Calgary, Alberta T2N 1N4, Canada
| | - D. Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive, N.W., Calgary, Alberta T2N 1N4, Canada
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20
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Luchini A, Delhom R, Cristiglio V, Knecht W, Wacklin-Knecht H, Fragneto G. Effect of ergosterol on the interlamellar spacing of deuterated yeast phospholipid multilayers. Chem Phys Lipids 2020; 227:104873. [PMID: 31926858 DOI: 10.1016/j.chemphyslip.2020.104873] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 12/14/2019] [Accepted: 01/03/2020] [Indexed: 12/17/2022]
Abstract
Sterols regulate several physico-chemical properties of biological membranes that are considered to be linked to function. Ergosterol is the main sterol molecule found in the cell membranes of yeasts and other fungi. Like the cholesterol found in mammalian cells, ergosterol has been proposed to have an ordering and condensing effect on saturated phospholipid membranes. The effects of cholesterol have been investigated extensively and result in an increase in the membrane thickness and the lipid acyl chain order. Less information is available on the effects of ergosterol on phospholipid membranes. Neutron Diffraction (ND) was used to characterize the effect of ergosterol on lipid multilayers prepared with deuterated natural phospholipids extracted from the yeast Pichia pastoris. The data show that the effect of ergosterol on membranes prepared from the natural phospholipid extract rich in unsaturated acyl chains, differs from what has been observed previously in membranes rich in saturated phospholipids. In contrast to cholesterol in synthetic phospholipid membranes, the presence of ergosterol up to 30 mol % in yeast phospholipid membranes only slightly altered the multilayer structure. In particular, only a small decrease in the multilayer d-spacing was observed as function of increasing ergosterol concentrations. This result highlights the need for further investigation to elucidate the effects of ergosterol in biological lipid mixtures.
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Affiliation(s)
- Alessandra Luchini
- Niels Bohr Institute, University of Copenhagen, UniversiteTsparken 5, 2100 Copenhagen, Denmark.
| | - Robin Delhom
- Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden
| | | | - Wolfgang Knecht
- Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden; Lund Protein Production Platform, Lund University, Sölvegatan 35, 22362 Lund, Sweden
| | - Hanna Wacklin-Knecht
- European Spallation Source ERIC, P.O. Box 176, 22100 Lund, Sweden; Division of Physical Chemistry, Lund University, P.O.Box 124, 22100 Lund, Sweden
| | - Giovanna Fragneto
- Institut Laue-Langevin, 71 Avenue Des Martyrs, 38000, Grenoble, France.
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21
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De Pascale M, Iacopetta D, Since M, Corvaisier S, Vie V, Paboeuf G, Hennequin D, Perato S, De Giorgi M, Sinicropi MS, Sopkova-De Oliveira Santos J, Voisin-Chiret AS, Malzert-Freon A. Synthesis of Pyridoclax Analogues: Insight into Their Druggability by Investigating Their Physicochemical Properties and Interactions with Membranes. ChemMedChem 2020; 15:136-154. [PMID: 31743599 DOI: 10.1002/cmdc.201900542] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 10/30/2019] [Indexed: 12/20/2022]
Abstract
Pyridoclax is considered a promising anticancer drug, acting as a protein-protein interaction disruptor, with potential applications in the treatment of ovarian, lung, and mesothelioma cancers. Eighteen sensibly selected structural analogues of Pyridoclax were synthesized, and their physicochemical properties were systematically assessed and analyzed. Moreover, considering that drug-membrane interactions play an essential role in understanding the mode of action of a given drug and its eventual toxic effects, membrane models were used to investigate such interactions in bulk (liposomes) and at the air-water interface. The measured experimental data on all original oligopyridines allowed the assessment of relative differences in terms of physicochemical properties, which could be determinant for their druggability, and hence for drug development.
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Affiliation(s)
| | - Domenico Iacopetta
- Department of Pharmacy Health and Nutritional Sciences, University of Calabria, 87036, Arcavacata di Rende, Italy
| | - Marc Since
- Normandie Univ, UniCaen, CERMN, 14000, Caen, France
| | | | - Véronique Vie
- Département Matière Molle BioMolécules aux Interfaces Fluides IPR, UR1, Campus de Beaulieu, 35042, Rennes Cedex, France
| | - Gilles Paboeuf
- Département Matière Molle BioMolécules aux Interfaces Fluides IPR, UR1, Campus de Beaulieu, 35042, Rennes Cedex, France
| | | | - Serge Perato
- Normandie Univ, UniCaen, CERMN, 14000, Caen, France
| | | | - Maria Stefania Sinicropi
- Department of Pharmacy Health and Nutritional Sciences, University of Calabria, 87036, Arcavacata di Rende, Italy
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22
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Usuda H, Hishida M, Kelley EG, Yamamura Y, Nagao M, Saito K. Interleaflet coupling of n-alkane incorporated bilayers. Phys Chem Chem Phys 2020; 22:5418-5426. [PMID: 31904060 DOI: 10.1039/c9cp06059f] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The relationship between the membrane bending modulus (κ) and compressibility modulus (KA) depends on the extent of coupling between the two monolayers (leaflets). Using neutron spin echo (NSE) spectroscopy, we investigate the effects of n-alkanes on the interleaflet coupling of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers. Structural studies with small-angle X-ray and neutron scattering (SAXS and SANS) showed that the bilayer thickness increased with increasing n-alkane length, while NSE suggested that the bilayers became softer. Additional measurements of the membrane thickness fluctuations with NSE suggested that the changes in elastic moduli were due to a decrease in coupling between the leaflets upon addition of the longer n-alkanes. The decreased coupling with elongating n-alkane length was explained based on the n-alkane distribution within the bilayers characterized by SANS measurement of bilayers composed of protiated DPPC and deuterated n-alkanes. A higher fraction of the incorporated long n-alkanes were concentrated at the central plane of the bilayers and decreased the physical interaction between the leaflets. Using NSE and SANS, we successfully correlated changes in the mesoscopic collective dynamics and microscopic membrane structure upon incorporation of n-alkanes.
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Affiliation(s)
- Hatsuho Usuda
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
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23
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Et-Thakafy O, Guyomarc'h F, Lopez C. Young modulus of supported lipid membranes containing milk sphingomyelin in the gel, fluid or liquid-ordered phase, determined using AFM force spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:1523-1532. [DOI: 10.1016/j.bbamem.2019.07.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 06/12/2019] [Accepted: 07/04/2019] [Indexed: 10/26/2022]
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24
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Abstract
The condensing effect and the ability of cholesterol (CHOL) to induce ordering in lipid films is a question of relevance in biological membranes such as the milk fat globule membrane (MFGM) in which the amount of CHOL influences the phase separation and mechanical resistance to rupture of coexisting phases relevant to emulsified food systems. Here, we study the effect of different salts (NaCl, CaCl2, MgCl2, LaCl3) on monolayers made of a model mixture of lipids (DPPC:DPPS 4:1) and CHOL. To this end, we apply Langmuir Film Balance to report a combined analysis of surface pressure-area (π-A) and surface potential-area (ΔV–A) isotherms along with Micro-Brewster Angle Microscopy (Micro-BAM) images of the monolayers in the presence of the different electrolytes. We show that the condensation of lipid by CHOL depends strongly on the nature of the ions by altering the shape and features of the π-A isotherms. ΔV–A isotherms provide further detail on the ion specific interactions with CHOL. Our results show that the condensation of lipids in the presence of CHOL depends on the combined action of ions and CHOL, which can alter the physical state of the monolayer.
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25
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Surmeier G, Paulus M, Salmen P, Dogan S, Sternemann C, Nase J. Cholesterol modulates the pressure response of DMPC membranes. Biophys Chem 2019; 252:106210. [PMID: 31265976 DOI: 10.1016/j.bpc.2019.106210] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 06/12/2019] [Accepted: 06/19/2019] [Indexed: 11/16/2022]
Abstract
In this work, the effect of cholesterol on the pressure response of solid-supported phospholipid multilayers is analyzed. It is shown that DMPC multilayers become highly pressure-responsive by the incorporation of low amounts of cholesterol, resulting in a strong pressure-induced expansion of the bilayer spacing. This is accompanied by a high tendency of the multilayer system to detach from the substrate. Increasing the cholesterol concentration reduces the pressure-induced expansion and the membrane structure remains largely unchanged upon pressurization, consequently the stability of the multilayers improves. For a determination of the influence of the substrate, the pressure-dependent behavior of multilayers is compared to that of solid-supported bilayers and multi-lamellar vesicles in bulk solution. While single-supported bilayers remain largely unaffected by external pressure independent of their cholesterol content, multi-lamellar vesicles and multilayers behave similarly.
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Affiliation(s)
- Göran Surmeier
- Fakultät Physik/DELTA, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Michael Paulus
- Fakultät Physik/DELTA, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Paul Salmen
- Fakultät Physik/DELTA, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Susanne Dogan
- Fakultät Physik/DELTA, Technische Universität Dortmund, 44221 Dortmund, Germany
| | | | - Julia Nase
- Fakultät Physik/DELTA, Technische Universität Dortmund, 44221 Dortmund, Germany.
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26
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Kamble S, Patil S, Kulkarni M, Murthy AVR. Spectroscopic Ellipsometry of fluid and gel phase lipid bilayers in hydrated conditions. Colloids Surf B Biointerfaces 2019; 176:55-61. [DOI: 10.1016/j.colsurfb.2018.12.061] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 11/20/2018] [Accepted: 12/20/2018] [Indexed: 11/26/2022]
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27
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Ayuyan AG, Cohen FS. The Chemical Potential of Plasma Membrane Cholesterol: Implications for Cell Biology. Biophys J 2019; 114:904-918. [PMID: 29490250 DOI: 10.1016/j.bpj.2017.12.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 12/21/2017] [Accepted: 12/28/2017] [Indexed: 10/17/2022] Open
Abstract
Cholesterol is abundant in plasma membranes and exhibits a variety of interactions throughout the membrane. Chemical potential accounts for thermodynamic consequences of molecular interactions, and quantifies the effective concentration (i.e., activity) of any substance participating in a process. We have developed, to our knowledge, the first method to measure cholesterol chemical potential in plasma membranes. This was accomplished by complexing methyl-β-cyclodextrin with cholesterol in an aqueous solution and equilibrating it with an organic solvent containing dissolved cholesterol. The chemical potential of cholesterol was thereby equalized in the two phases. Because cholesterol is dilute in the organic phase, here activity and concentration were equivalent. This equivalence allowed the amount of cholesterol bound to methyl-β-cyclodextrin to be converted to cholesterol chemical potential. Our method was used to determine the chemical potential of cholesterol in erythrocytes and in plasma membranes of nucleated cells in culture. For erythrocytes, the chemical potential did not vary when the concentration was below a critical value. Above this value, the chemical potential progressively increased with concentration. We used standard cancer lines to characterize cholesterol chemical potential in plasma membranes of nucleated cells. This chemical potential was significantly greater for highly metastatic breast cancer cells than for nonmetastatic breast cancer cells. Chemical potential depended on density of the cancer cells. A method to alter and fix the cholesterol chemical potential to any value (i.e., a cholesterol chemical potential clamp) was also developed. Cholesterol content did not change when cells were clamped for 24-48 h. It was found that the level of activation of the transcription factor STAT3 increased with increasing cholesterol chemical potential. The cholesterol chemical potential may regulate signaling pathways.
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Affiliation(s)
- Artem G Ayuyan
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, Illinois.
| | - Fredric S Cohen
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, Illinois.
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28
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Garcia A, Zou H, Hossain KR, Xu QH, Buda A, Clarke RJ. Polar Interactions Play an Important Role in the Energetics of the Main Phase Transition of Phosphatidylcholine Membranes. ACS OMEGA 2019; 4:518-527. [PMID: 31459346 PMCID: PMC6648055 DOI: 10.1021/acsomega.8b03102] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 12/26/2018] [Indexed: 06/09/2023]
Abstract
Conformational changes of membrane proteins are accompanied by deformation in the surrounding lipid bilayer. To gain insight into the energetics of membrane deformation, the phase behavior of dimyristoylphosphatidylcholine (DMPC) membranes in the presence of the dipole potential, ψd, modifiers was investigated by differential scanning calorimetry. 7-Ketocholesterol, which weakens ψd and reduces membrane-perpendicular dipole-dipole repulsion, causes a discrete second peak on the high-temperature side of the main transition, whereas 6-ketocholestanol, which strengthens ψd and increases membrane-perpendicular dipole-dipole repulsion, merely produces a shoulder. Measurements on pure DMPC vesicles showed that the observed temperature profile could not be explained by a single endothermic process, that is, breaking of van der Waals forces between hydrocarbon chains alone. Removal of NaCl from the buffer caused an increase in the main transition temperature and the appearance of an obvious shoulder, implicating polar interactions. Consideration of the phosphatidylcholine (PC) head group dipole moment indicates direct interactions between PC dipoles that are unlikely to account for the additional process. It seems more likely that the breaking of an in-plane hydrogen-bonded network consisting of hydrating water dipoles together with zwitterionic lipid head groups is responsible. The evidence presented supports the idea that the breaking of van der Waals forces between lipid tails required for the main phase transition of PC membranes is coupled to partial breaking of a hydrogen-bonded network at the membrane surface.
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Affiliation(s)
- Alvaro Garcia
- School
of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Haipei Zou
- School
of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Khondker R. Hossain
- School
of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia
- The
University of Sydney Nano Institute, Sydney, New South Wales 2006, Australia
| | - Qikui Henry Xu
- School
of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Annabelle Buda
- School
of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Ronald J. Clarke
- School
of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia
- The
University of Sydney Nano Institute, Sydney, New South Wales 2006, Australia
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29
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Yamamoto S, Ohta A, Hossain F, Anjani G, Asakawa H, Asakawa T. Solubilization of Genistein in Phospholipid Vesicles and Their Atioxidant Capacity. J Oleo Sci 2019; 68:61-66. [PMID: 30542013 DOI: 10.5650/jos.ess18181] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Water-insoluble genistein was solubilized in aqueous medium by using phospholipid vesicles composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dioleoyl-sn-glycerophosphocholine (DOPC) with 0-30% cholesterol. For each vesicle, the maximum solubilization amount of genistein was investigated by X-ray scattering measurement. In addition, the antioxidant capacity of the solubilized genistein was evaluated by the ABTS assay. Genistein was found to be solubilized by 10-20% and 40-50% of the vesicle concentrations of pure DPPC and DOPC respectively. The maximum solubilization amount of genistein decreased to 0-10% and 20-30% when 30% of cholesterol is present in the respective vesicles. Cholesterol is solubilized in a hydrophobic core whereas genistein is solubilized in the polar head region or in the polar-apolar interface. The overlapping of solubilizing sites affected the solubilization of genistein when cholesterol was present in the vesicles. Moreover, the lamellar interval was largely affected by cholesterol in compared to the little impact of genistein because the later can indirectly affect the acyl chains. Genistein solubilized in DOPC showed the same degree of antioxidant capacity as that of vesicle-free genistein system. On the other hand, genistein solubilized in DPPC had lower antioxidant activity than the former systems. The distinction of antioxidant activity at different systems probably related to the difference of accessibility of ABTS radical cation to solubilized genistein through different vesicles. Finally, cholesterol-free DOPC vesicles were found to be the best solubilizer for genistein among the investigated systems.
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Affiliation(s)
- Shunya Yamamoto
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University
| | - Akio Ohta
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University
| | - Faisal Hossain
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University
| | - Gemala Anjani
- Department of Nutrition Science, Faculty of Medicine, Diponegoro University
| | - Hitoshi Asakawa
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University
| | - Tsuyoshi Asakawa
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University
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30
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Post-insertion parameters of PEG-derivatives in phosphocholine-liposomes. Int J Pharm 2018; 552:414-421. [DOI: 10.1016/j.ijpharm.2018.10.028] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 09/20/2018] [Accepted: 10/09/2018] [Indexed: 12/31/2022]
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Neunert G, Tomaszewska-Gras J, Siejak P, Pietralik Z, Kozak M, Polewski K. Disruptive effect of tocopherol oxalate on DPPC liposome structure: DSC, SAXS, and fluorescence anisotropy studies. Chem Phys Lipids 2018; 216:104-113. [PMID: 30308198 DOI: 10.1016/j.chemphyslip.2018.10.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 09/26/2018] [Accepted: 10/05/2018] [Indexed: 02/05/2023]
Abstract
α-Tocopherol oxalate (TO), a tocopherol ester derivative, was investigated for its effect on the structural changes of fully hydrated 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposomes, as a function of concentration and temperature, by applying differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS), and DPH fluorescence anisotropy methods. The DSC and DPH anisotropy data indicated that TO embedded into DPPC membrane lowered the enthalpy (ΔHm) and temperature (Tm) of the main phase transition as well its cooperativity. Fluidization of the membrane at a lowered temperature was accompanied by formation of mixed structures of tocopherol-enriched domains. SAXS studies showed the formation of various ordered structures in DPPC gel-phase during incorporation of TO into the bilayer, as evidenced by the existence of lamellar phases with repeat distances (d) of 6.13 and 6.87 nm, assigned to TO-enriched domains and a lamellar, liquid-ordered DPPC phase with d = 8.45 nm at increasing TO concentrations with lowering and broadening of the Bragg peaks, and diffuse scattering, characteristic of a fluid Lα phase, were observed. In DPPC fluid-phase, the increasing presence of TO at low concentrations resulted in the appearance of a liquid-ordered phase with repeat d = 6.9 nm coexistent with a lamellar structure with d = 9.2 nm, assigned to liquid-disordered structures. An increasing repeat distance observed with raising the TO amount in the DPPC bilayer evolved from an increasing interlamellar water layer of increasing thickness. Presence of TO facilitated penetration of water molecules into the acyl chain region which decreased van der Waals interactions in the bilayer. The DSC, SAXS, and fluorescence anisotropy data established that TO exhibited pronounced disruptive activity in DPPC membranes compared to α-tocopherol. The driving force of the observed action was attributed to electrostatic and dipole interactions of the acidic moiety with the polar head group of phospholipids in the interface region of the bilayer.
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Affiliation(s)
- Grażyna Neunert
- Department of Physics and Biophysics, Faculty of Food and Nutrition Sciences, Poznan University of Life Sciences, Wojska Polskiego 38/42, 60-637, Poznan, Poland
| | - Jolanta Tomaszewska-Gras
- Department of Food Quality Management, Faculty of Food and Nutrition Sciences, Poznan University of Life Sciences, Wojska Polskiego 31/33, 60-624, Poznan, Poland
| | - Przemyslaw Siejak
- Department of Physics and Biophysics, Faculty of Food and Nutrition Sciences, Poznan University of Life Sciences, Wojska Polskiego 38/42, 60-637, Poznan, Poland
| | - Zuzanna Pietralik
- Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614, Poznań, Poland
| | - Maciej Kozak
- Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614, Poznań, Poland
| | - Krzysztof Polewski
- Department of Physics and Biophysics, Faculty of Food and Nutrition Sciences, Poznan University of Life Sciences, Wojska Polskiego 38/42, 60-637, Poznan, Poland.
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Steer D, Leung SSW, Meiselman H, Topgaard D, Leal C. Structure of Lung-Mimetic Multilamellar Bodies with Lipid Compositions Relevant in Pneumonia. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:7561-7574. [PMID: 29847137 DOI: 10.1021/acs.langmuir.8b01359] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The hierarchical assembly of lipids, as modulated by composition and environment, plays a significant role in the function of biological membranes and a myriad of diseases. Elevated concentrations of calcium ions and cardiolipin (CL), an anionic tetra-alkyl lipid found in mitochondria and some bacterial cell membranes, have been implicated in pneumonia recently. However, their impact on the physicochemical properties of lipid assemblies in lungs and how it impairs alveoli function is still unknown. We use small- and wide-angle X-ray scattering (S/WAXS) and solid-state nuclear magnetic resonance (ssNMR) to probe the structure and dynamics of lung-mimetic multilamellar bodies (MLBs) in the presence of Ca2+ and CL. We conjecture that CL overexpressed in the hypophase of alveoli strongly affects the structure of lung-lipid bilayers and their stacking in the MLBs. Specifically, S/WAXS data revealed that CL induces significant shrinkage of the water-layer separating the concentric bilayers in multilamellar aggregates. ssNMR measurements indicate that this interbilayer tightening is due to undulation repulsion damping as CL renders the glycerol backbone of the membranes significantly more static. In addition to MLB dehydration, CL promotes intrabilayer phase separation into saturated-rich and unsaturated-rich lipid domains that couple across multiple layers. Expectedly, addition of Ca2+ screens the electrostatic repulsion between negatively charged lung membranes. However, when CL is present, addition of Ca2+ results in an apparent interbilayer expansion likely due to local structural defects. Combining S/WAXS and ssNMR on systems with compositions pertinent to healthy and unhealthy lung membranes, we propose how alteration of the physiochemical properties of MLBs can critically impact the breathing cycle.
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Affiliation(s)
| | | | | | - Daniel Topgaard
- Division of Physical Chemistry, Center of Chemistry and Chemical Engineering , Lund University , SE-221 00 Lund , Sweden
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Kumar K, Chavarha M, Loney RW, Weiss TM, Rananavare SB, Hall SB. The L γ Phase of Pulmonary Surfactant. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:6601-6611. [PMID: 29715426 PMCID: PMC6526724 DOI: 10.1021/acs.langmuir.8b00460] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
To determine how different components affect the structure of pulmonary surfactant, we measured X-ray scattering by samples derived from calf surfactant. The surfactant phospholipids demonstrated the essential characteristics of the Lγ phase: a unit cell with a lattice constant appropriate for two bilayers, and crystalline chains detected by wide-angle X-ray scattering (WAXS). The electron density profile, obtained from scattering by oriented films at different relative humidities (70-97%), showed that the two bilayers, arranged as mirror images, each contain two distinct leaflets with different thicknesses and profiles. The detailed structures suggest one ordered leaflet that would contain crystalline chains and one disordered monolayer likely to contain the anionic compounds, which constitute ∼10% of the surfactant phospholipids. The spacing and temperature dependence detected by WAXS fit with an ordered leaflet composed of dipalmitoyl phosphatidylcholine. Physiological levels of cholesterol had no effect on this structure. Removing the anionic phospholipids prevented formation of the Lγ phase. The cationic surfactant proteins inhibited Lγ structures, but at levels unlikely related to charge. Because the Lγ phase, if arranged properly, could produce a self-assembled ordered interfacial monolayer, the structure could have important functional consequences. Physiological levels of the proteins, however, inhibit formation of the Lγ structures at high relative humidities, making their physiological significance uncertain.
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Affiliation(s)
- Kamlesh Kumar
- Departments of Biochemistry & Molecular Biology, Medicine, and Physiology & Pharmacology, Oregon Heath & Science University, Portland, OR 97239-3098
| | - Mariya Chavarha
- Departments of Biochemistry & Molecular Biology, Medicine, and Physiology & Pharmacology, Oregon Heath & Science University, Portland, OR 97239-3098
| | - Ryan W. Loney
- Departments of Biochemistry & Molecular Biology, Medicine, and Physiology & Pharmacology, Oregon Heath & Science University, Portland, OR 97239-3098
| | - Thomas M. Weiss
- Stanford University, SLAC/SSRL Building 137, 2575 Sand Hill Road MS69, Menlo Park, CA 94025
| | | | - Stephen B. Hall
- Departments of Biochemistry & Molecular Biology, Medicine, and Physiology & Pharmacology, Oregon Heath & Science University, Portland, OR 97239-3098
- To whom correspondence should be addressed: Stephen B. Hall, Pulmonary & Critical Care Medicine, Mail Code UHN-67, Oregon Health & Science University, Portland, Oregon 97239-3098, , Telephone: (503) 494-6667
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Barattin M, Mattarei A, Balasso A, Paradisi C, Cantù L, Del Favero E, Viitala T, Mastrotto F, Caliceti P, Salmaso S. pH-Controlled Liposomes for Enhanced Cell Penetration in Tumor Environment. ACS APPLIED MATERIALS & INTERFACES 2018; 10:17646-17661. [PMID: 29737834 DOI: 10.1021/acsami.8b03469] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
An innovative pH-switchable colloidal system that can be exploited for site-selective anticancer drug delivery has been generated by liposome decoration with a new novel synthetic non-peptidic oligo-arginine cell-penetration enhancer (CPE) and a quenching PEGylated counterpart that detaches from the vesicle surface under the acidic conditions of tumors. The CPE module ( Arg4- DAG) is formed by four arginine units conjugated to a first-generation (G1) 2,2-bis(hydroxymethyl)propionic acid (bis-MPA)/2,2-bis(aminomethyl)propionic acid (bis-AMPA) polyester dendron terminating with 1,2-distearoyl-3-azidopropane for liposome bilayer insertion. The zeta potential of the Arg4- DAG-decorated liposomes increased up to +32 mV as the Arg4- DAG/lipids molar ratio increased. The Arg4- DAG liposome shielding at pH 7.4 was provided by methoxy-PEG5 kDa-polymethacryloyl sulfadimethoxine (mPEG5 kDa-SDM8) with 7.1 apparent p Ka. Zeta potential, surface plasmon resonance and synchrotron small-angle X-ray scattering analyses showed that at pH 7.4 mPEG5 kDa-SDM8 associates with polycationic Arg4- DAG-decorated liposomes yielding liposomes with neutral zeta potential. At pH 6.5, which mimics the tumor environment, mPEG5 kDa-SDM8 detaches from the liposome surface yielding Arg4- DAG exposure. Flow cytometry and confocal microscopy showed a 30-fold higher HeLa cancer cell association of the Arg4- DAG-decorated liposomes compared to non-decorated liposomes. At pH 7.4, the mPEG5 kDa-SDM8-coated liposomes undergo low cell association while remarkable cell association occurred at pH 6.5, which allowed for the controlled intracellular delivery of model macromolecules and small molecules loaded in the liposome under tumor conditions.
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Affiliation(s)
- Michela Barattin
- Department of Pharmaceutical and Pharmacological Sciences , University of Padova , Via F. Marzolo 5 , Padova 35131 , Italy
| | - Andrea Mattarei
- Department of Chemical Sciences , University of Padova , Via F. Marzolo 1 , Padova 35131 , Italy
| | - Anna Balasso
- Department of Pharmaceutical and Pharmacological Sciences , University of Padova , Via F. Marzolo 5 , Padova 35131 , Italy
| | - Cristina Paradisi
- Department of Chemical Sciences , University of Padova , Via F. Marzolo 1 , Padova 35131 , Italy
| | - Laura Cantù
- Department of Medical Biotechnologies and Traslational Medicine , University of Milano , LITA, Via F.lli Cervi, 93 , Segrate 20090 , Italy
| | - Elena Del Favero
- Department of Medical Biotechnologies and Traslational Medicine , University of Milano , LITA, Via F.lli Cervi, 93 , Segrate 20090 , Italy
| | - Tapani Viitala
- Centre for Drug Research and Division of Pharmaceutical Biosciences, Faculty of Pharmacy , University of Helsinki , Viikinkaari 5 , Helsinki FI-00014 , Finland
| | - Francesca Mastrotto
- Department of Pharmaceutical and Pharmacological Sciences , University of Padova , Via F. Marzolo 5 , Padova 35131 , Italy
| | - Paolo Caliceti
- Department of Pharmaceutical and Pharmacological Sciences , University of Padova , Via F. Marzolo 5 , Padova 35131 , Italy
| | - Stefano Salmaso
- Department of Pharmaceutical and Pharmacological Sciences , University of Padova , Via F. Marzolo 5 , Padova 35131 , Italy
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Jaschonek S, Cascella M, Gauss J, Diezemann G, Milano G. Intramolecular structural parameters are key modulators of the gel-liquid transition in coarse grained simulations of DPPC and DOPC lipid bilayers. Biochem Biophys Res Commun 2018; 498:327-333. [PMID: 29101041 DOI: 10.1016/j.bbrc.2017.10.132] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/29/2017] [Accepted: 10/23/2017] [Indexed: 12/11/2022]
Abstract
The capability of coarse-grained models based on the MARTINI mapping to reproduce the gel-liquid phase transition in saturated and unsaturated model lipids was investigated. We found that the model is able to reproduce a lower critical temperature for 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) with respect to 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Nonetheless, the appearance of a gel phase for DOPC is strictly dependent on the intramolecular parameters chosen to model its molecular structure. In particular, we show that the bending angle at the coarse-grained bead corresponding to the unsaturated carbon-carbon bond acts as an order parameter determining the temperature of the phase transition. Structural analysis of the molecular dynamics simulations runs evidences that in the gel phase, the packing of the lipophilic tails of DOPC assume a different conformation than in the liquid phase. In the latter phase, the DOPC geometry resembles that of the relaxed free molecule. DPPC:DOPC mixtures show a single phase transition temperature, indicating that the observation of a phase separation between the two lipids requires the simulation of systems with sizes much larger than the ones used here.
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Affiliation(s)
- Stefan Jaschonek
- Institut für Physikalische Chemie, Universität Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany.
| | - Michele Cascella
- Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, Postboks 1033 Blindern, N-0315 Oslo, Norway.
| | - Jürgen Gauss
- Institut für Physikalische Chemie, Universität Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany.
| | - Gregor Diezemann
- Institut für Physikalische Chemie, Universität Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany.
| | - Giuseppe Milano
- Dipartimento di Chimica e Biologia, Università di Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano, Italy.
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Cholesterol induced asymmetry in DOPC bilayers probed by AFM force spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:953-959. [PMID: 29408513 DOI: 10.1016/j.bbamem.2018.01.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 01/24/2018] [Accepted: 01/28/2018] [Indexed: 11/21/2022]
Abstract
Cholesterol induced mechanical effects on artificial lipid bilayers are well known and have been thoroughly investigated by AFM force spectroscopy. However, dynamics of cholesterol impingement into bilayers at various cholesterol concentrations and their effects have not been clearly understood. In this paper we present, the effect of cholesterol as a function of its concentration in a simple single component dioleoylphosphatidylcholine (DOPC) bilayer. The nature of measured breakthrough forces on a bilayer with the addition of cholesterol, suggested that it is not just responsible to increase the mechanical stability but also introduces irregularities across the leaflets of the bilayer. This cholesterol induced asymmetry across the (in the inner and outer leaflets) bilayer is related to the phenomena of interleaflet coupling and is a function of cholesterol concentration probed by AFM can provide an unprecedented direction on mechanical properties of lipid membrane as it can be directly correlated to biophysical properties of a cell membrane.
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Williams AT, Donno R, Tirelli N, Dryfe RA. Phospholipid-mediated exfoliation as a facile preparation method for graphene suspensions. RSC Adv 2018; 8:19220-19225. [PMID: 35539657 PMCID: PMC9080625 DOI: 10.1039/c8ra03365j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 05/16/2018] [Indexed: 11/25/2022] Open
Abstract
This paper deals with simple, inexpensive and ‘green’ methods of production for graphene in colloidal dispersion. Herein, we report on such a method by preparing aqueous graphene dispersions via ultrasonic exfoliation in the presence of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). The product predominantly consists of few-layer graphene flakes coated by DOPC with a lateral size of a few tens to hundreds of nm, as confirmed by Raman and X-ray photoelectron spectroscopies, thermogravimetric analysis (TGA), dynamic light scattering (DLS) and atomic force microscopy (AFM). The novelty of this method lies in its dependence on a typical soft matter property: the fluidity of the hydrophobic chains. Stiffer phospholipids such as 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC, which possesses two palmitoyl chains) or 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC, one palmitoyl, one oleyl chain) are ineffective at dispersing graphene; however, in the presence of cholesterol these phospholipids also become effective mediators. The phospholipid coating renders the flakes compatible with biological environments. A simple, inexpensive and ‘green’ method of production for graphene in colloidal dispersion.![]()
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Affiliation(s)
| | - Roberto Donno
- Laboratory of Polymers and Biomaterials
- Fondazione Istituto Italiano di Tecnologia
- Genoa
- Italy
| | - Nicola Tirelli
- Laboratory of Polymers and Biomaterials
- Fondazione Istituto Italiano di Tecnologia
- Genoa
- Italy
- NorthWest Centre for Advanced Drug Delivery
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Khondker A, Alsop RJ, Dhaliwal A, Saem S, Moran-Mirabal JM, Rheinstädter MC. Membrane Cholesterol Reduces Polymyxin B Nephrotoxicity in Renal Membrane Analogs. Biophys J 2017; 113:2016-2028. [PMID: 29117525 DOI: 10.1016/j.bpj.2017.09.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/17/2017] [Accepted: 09/13/2017] [Indexed: 01/21/2023] Open
Abstract
Polymyxin B (PmB) is a "last-line" antibiotic scarcely used due to its nephrotoxicity. However, the molecular basis for antibiotic nephrotoxicity is not clearly understood. We prepared kidney membrane analogs of detergent-susceptible membranes, depleted of cholesterol, and cholesterol enriched, resistant membranes. In both analogs, PmB led to membrane damage. By combining x-ray diffraction, molecular dynamics simulations, and electrochemistry, we present evidence for two populations of PmB molecules: peptides that lie flat on the membranes, and an inserted state. In cholesterol depleted membranes, PmB forms clusters on the membranes leading to an indentation of the bilayers and increase in water permeation. The inserted peptides formed aggregates in the membrane core leading to further structural instabilities and increased water intake. The presence of cholesterol in the resistant membrane analogs led to a significant decrease in membrane damage. Although cholesterol did not inhibit peptide insertion, it minimized peptide clustering and water intake through stabilization of the bilayer structure and suppression of lipid and peptide mobility.
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Affiliation(s)
- Adree Khondker
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
| | - Richard J Alsop
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
| | - Alexander Dhaliwal
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
| | - Sokunthearath Saem
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, Canada
| | - Jose M Moran-Mirabal
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, Canada
| | - Maikel C Rheinstädter
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada.
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Kang M, Lee B, Leal C. Three-Dimensional Microphase Separation and Synergistic Permeability in Stacked Lipid-Polymer Hybrid Membranes. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2017; 29:9120-9132. [PMID: 31097879 PMCID: PMC6516788 DOI: 10.1021/acs.chemmater.7b02845] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We present new structures of soft-material thin films that augment the functionality of substrate-mediated delivery systems. A hybrid material composed of phospholipids and block copolymers adopts a multilayered membrane structure supported on a solid surface. The hybrid films comprise intentional intramembrane heterogeneities that register across multilayers. These stacked domains convey unprecedented enhancement and control of permeability of solutes across micrometer-thick films. Using grazing incidence X-ray scattering, phase contrast atomic force microscopy, and confocal microscopy, we observed that in each lamella, lipid and polymers partition unevenly within the membrane plane segregating into lipid- or polymer-rich domains. Interestingly, we found evidence that like-domains align in registry across multilayers, thereby making phase separation three-dimensional. Phase boundaries exist over extended length scales to compensate the height mismatch between lipid and polymer molecules. We show that microphase separation in hybrid films can be exploited to augment the capability of drug-eluting substrates. Lipid-polymer hybrid films loaded with paclitaxel show synergistic permeability of drug compared to single-component counterparts. We present a thorough structural study of stacked lipid-polymer hybrid membranes and propose that the presence of registered domains and domain boundaries impart enhanced drug release functionality. This work offers new perspectives in designing thin films for controlled delivery applications.
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Affiliation(s)
- Minjee Kang
- Department of Materials Science and Engineering, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
| | - Byeongdu Lee
- X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Cecilia Leal
- Department of Materials Science and Engineering, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
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40
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Werner S, Ebenhan J, Poppe M, Poppe S, Ebert H, Tschierske C, Bacia K. Effects of Lateral and Terminal Chains of X-Shaped Bolapolyphiles with Oligo(phenylene ethynylene) Cores on Self-Assembly Behavior. Part 2: Domain Formation by Self-Assembly in Lipid Bilayer Membranes. Polymers (Basel) 2017; 9:E476. [PMID: 30965779 PMCID: PMC6418688 DOI: 10.3390/polym9100476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 09/20/2017] [Accepted: 09/22/2017] [Indexed: 01/01/2023] Open
Abstract
Supramolecular self-assembly of membrane constituents within a phospholipid bilayer creates complex functional platforms in biological cells that operate in intracellular signaling, trafficking and membrane remodeling. Synthetic polyphilic compounds of macromolecular or small size can be incorporated into artificial phospholipid bilayers. Featuring three or four moieties of different philicities, they reach beyond ordinary amphiphilicity and open up avenues to new functions and interaction concepts. Here, we have incorporated a series of X-shaped bolapolyphiles into DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) bilayers of giant unilamellar vesicles. The bolapolyphiles consist of a rod-like oligo(phenylene ethynylene) (OPE) core, hydrophilic glycerol-based headgroups with or without oligo(ethylene oxide) expansions at both ends and two lateral alkyl chains attached near the center of the OPE core. In the absence of DPPC and water, the compounds showed thermotropic liquid-crystalline behavior with a transition between polyphilic and amphiphilic assembly (see part 1 in this issue). In DPPC membranes, various trends in the domain morphologies were observed upon structure variations, which entailed branched alkyl chains of various sizes, alkyl chain semiperfluorination and size expansion of the headgroups. Observed effects on domain morphology are interpreted in the context of the bulk behavior (part 1) and of a model that was previously developed based on spectroscopic and physicochemical data.
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Affiliation(s)
- Stefan Werner
- Department of Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle, Germany.
| | - Jan Ebenhan
- Department of Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle, Germany.
| | - Marco Poppe
- Department of Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 2, 06120 Halle, Germany.
| | - Silvio Poppe
- Department of Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 2, 06120 Halle, Germany.
| | - Helgard Ebert
- Department of Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 2, 06120 Halle, Germany.
| | - Carsten Tschierske
- Department of Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 2, 06120 Halle, Germany.
| | - Kirsten Bacia
- Department of Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle, Germany.
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41
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Huang FY, Chiu CC. Interplay between alkyl chain asymmetry and cholesterol addition in the rigid ion pair amphiphile bilayer systems. J Chem Phys 2017; 146:035102. [PMID: 28109215 DOI: 10.1063/1.4974089] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Ion pair amphiphile (IPA), a molecular complex composed of a pair of cationic and anionic surfactants, has been proposed as a novel phospholipid substitute. Controlling the physical stability of IPA vesicles is important for its application developments such as cosmetic and drug deliveries. To investigate the effects of IPA alkyl chain combinations and the cholesterol additive on the structural and mechanical properties of IPA vesicular bilayers, we conducted a series of molecular dynamics studies on the hexadecyltrimethylammonium-dodecylsulfate (HTMA-DS) and dodecyltrimethylammonium-hexadecylsulfate (DTMA-HS) IPA bilayers with cholesterol. We found that both IPA bilayers are in the gel phase at 298 K, consistent with experimental observations. Compared with the HTMA-DS system, the DTMA-HS bilayer has more disordered alkyl chains in the hydrophobic region. When adding cholesterol, it induces alkyl chain ordering around its rigid sterol ring. Yet, cholesterol increases the molecular areas for all species and disturbs the molecular packing near the hydrophilic region and the bilayer core. Cholesterol also promotes the alkyl chain mismatch between the IPA moieties, especially for the DTMA-HS bilayer. The combined effects lead to non-monotonically enhancement of the membrane mechanical moduli for both IPA-cholesterol systems. Furthermore, cholesterol can form H-bonds with the alkylsulfate and thus enhance the contribution of alkylsulfate to the overall mechanical moduli. Combined results provide valuable molecular insights into the roles of each IPA component and the cholesterol on modulating the IPA bilayer properties.
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Affiliation(s)
- Fong-Yin Huang
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
| | - Chi-Cheng Chiu
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
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42
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Sybachin AV, Zaborova OV, Efimova AA, Ballauff M, Yaroslavov AA. Electrostatic complexes of liquid and solid liposomes with spherical polycationic brushes. POLYMER SCIENCE SERIES C 2017. [DOI: 10.1134/s181123821701012x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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43
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Drolle E, Bennett WFD, Hammond K, Lyman E, Karttunen M, Leonenko Z. Molecular dynamics simulations and Kelvin probe force microscopy to study of cholesterol-induced electrostatic nanodomains in complex lipid mixtures. SOFT MATTER 2017; 13:355-362. [PMID: 27901162 PMCID: PMC7733735 DOI: 10.1039/c6sm01350c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The molecular arrangement of lipids and proteins within biomembranes and monolayers gives rise to complex film morphologies as well as regions of distinct electrical surface potential, topographical and electrostatic nanoscale domains. To probe these nanodomains in soft matter is a challenging task both experimentally and theoretically. This work addresses the effects of cholesterol, lipid composition, lipid charge, and lipid phase on the monolayer structure and the electrical surface potential distribution. Atomic force microscopy (AFM) was used to resolve topographical nanodomains and Kelvin probe force microscopy (KPFM) to resolve electrical surface potential of these nanodomains in lipid monolayers. Model monolayers composed of dipalmitoylphosphatidylcholine (DPPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), 1,2-dioleoyl-sn-glycero-3-[phospho-rac-(3-lysyl(1-glycerol))] (DOPG), and cholesterol were studied. It is shown that cholesterol changes nanoscale domain formation, affecting both topography and electrical surface potential. The molecular basis for differences in electrical surface potential was addressed with atomistic molecular dynamics (MD). MD simulations are compared the experimental results, with 100 s of mV difference in electrostatic potential between liquid-disordered bilayer (Ld, less cholesterol and lower chain order) and a liquid-ordered bilayer (Lo, more cholesterol and higher chain order). Importantly, the difference in electrostatic properties between Lo and Ld phases suggests a new mechanism by which membrane composition couples to membrane function.
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Affiliation(s)
- E Drolle
- Department of Biology, University of Waterloo, Canada. and Waterloo Institute of Nanotechnology, University of Waterloo, Canada
| | - W F D Bennett
- Department of Physics and Astronomy and Department of Chemistry and Biochemistry, University of California, Santa Barbara, USA
| | - K Hammond
- Department of Physics and Astronomy, University of Waterloo, Canada
| | - E Lyman
- Department of Physics and Astronomy, 217 Sharp Lab, Newark, USA
| | - M Karttunen
- Department of Mathematics and Computer Science & Institute for Complex Molecular Systems, Eindhoven University of Technology, MetaForum, 5600 MB Eindhoven, the Netherlands
| | - Z Leonenko
- Department of Biology, University of Waterloo, Canada. and Waterloo Institute of Nanotechnology, University of Waterloo, Canada and Department of Physics and Astronomy, University of Waterloo, Canada
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The Molecular Structure of Human Red Blood Cell Membranes from Highly Oriented, Solid Supported Multi-Lamellar Membranes. Sci Rep 2017; 7:39661. [PMID: 28045119 PMCID: PMC5206716 DOI: 10.1038/srep39661] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 11/24/2016] [Indexed: 12/30/2022] Open
Abstract
We prepared highly oriented, multi-lamellar stacks of human red blood cell (RBC) membranes applied on silicon wafers. RBC ghosts were prepared by hemolysis and applied onto functionalized silicon chips and annealed into multi-lamellar RBC membranes. High resolution X-ray diffraction was used to determine the molecular structure of the stacked membranes. We present direct experimental evidence that these RBC membranes consist of nanometer sized domains of integral coiled-coil peptides, as well as liquid ordered (lo) and liquid disordered (ld) lipids. Lamellar spacings, membrane and hydration water layer thicknesses, areas per lipid tail and domain sizes were determined. The common drug aspirin was added to the RBC membranes and found to interact with RBC membranes and preferably partition in the head group region of the lo domain leading to a fluidification of the membranes, i.e., a thinning of the bilayers and an increase in lipid tail spacing. Our results further support current models of RBC membranes as patchy structures and provide unprecedented structural details of the molecular organization in the different domains.
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45
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Hartkamp R, Moore TC, Iacovella CR, Thompson MA, Bulsara PA, Moore DJ, McCabe C. Structural Properties of Phospholipid-based Bilayers with Long-Chain Alcohol Molecules in the Gel Phase. J Phys Chem B 2016; 120:12863-12871. [DOI: 10.1021/acs.jpcb.6b10192] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Remco Hartkamp
- Department
of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
- Multiscale
Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Timothy C. Moore
- Department
of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
- Multiscale
Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Christopher R. Iacovella
- Department
of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
- Multiscale
Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Michael A. Thompson
- GlaxoSmithKline Consumer Healthcare, 184 Liberty Corner Road, Suite 200, Warren, New Jersey 07059, United States
| | - Pallav A. Bulsara
- GlaxoSmithKline Consumer Healthcare, 184 Liberty Corner Road, Suite 200, Warren, New Jersey 07059, United States
| | - David J. Moore
- GlaxoSmithKline Consumer Healthcare, 184 Liberty Corner Road, Suite 200, Warren, New Jersey 07059, United States
| | - Clare McCabe
- Department
of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
- Multiscale
Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, Tennessee 37212, United States
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
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46
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Ma Y, Ghosh SK, DiLena DA, Bera S, Lurio LB, Parikh AN, Sinha SK. Cholesterol Partition and Condensing Effect in Phase-Separated Ternary Mixture Lipid Multilayers. Biophys J 2016; 110:1355-66. [PMID: 27028645 DOI: 10.1016/j.bpj.2016.02.022] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 02/05/2016] [Accepted: 02/16/2016] [Indexed: 01/08/2023] Open
Abstract
The cholesterol partitioning and condensing effect in the liquid-ordered (Lo) and liquid-disordered (Ld) phases were systematically investigated for ternary mixture lipid multilayers consisting of 1:1 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1,2-dioleoyl-sn-glycero-3-phosphocholine with varying concentrations of cholesterol. X-ray lamellar diffraction was used to deduce the electron density profiles of each phase. The cholesterol concentration in each phase was quantified by fitting of the electron density profiles with a newly invented basic lipid profile scaling method that minimizes the number of fitting parameters. The obtained cholesterol concentration in each phase versus total cholesterol concentration in the sample increases linearly for both phases. The condensing effect of cholesterol in ternary lipid mixtures was evaluated in terms of phosphate-to-phosphate distances, which together with the estimated cholesterol concentration in each phase was converted into an average area per molecule. In addition, the cholesterol position was determined to a precision of (±0.7Å) and an increase of disorder in the lipid packing in the Lo phase was observed for total cholesterol concentration of 20∼30%.
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Affiliation(s)
- Yicong Ma
- Department of Physics, University of California-San Diego, La Jolla, California
| | - Sajal K Ghosh
- Department of Physics, University of California-San Diego, La Jolla, California
| | - David A DiLena
- Department of Physics, University of California-San Diego, La Jolla, California
| | - Sambhunath Bera
- Department of Physics, University of California-San Diego, La Jolla, California
| | - Laurence B Lurio
- Department of Physics, Northern Illinois University, DeKalb, Illinois
| | - Atul N Parikh
- Department of Biomedical Engineering and Department of Chemical Engineering and Materials Science, University of California-Davis, Davis, California
| | - Sunil K Sinha
- Department of Physics, University of California-San Diego, La Jolla, California.
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47
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Beltramo PJ, Vermant J. Simple Optical Imaging of Nanoscale Features in Free-Standing Films. ACS OMEGA 2016; 1:363-370. [PMID: 30023480 PMCID: PMC6044614 DOI: 10.1021/acsomega.6b00125] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 08/31/2016] [Indexed: 05/19/2023]
Abstract
Measuring thicknesses in thin films with high spatial and temporal resolution is of prime importance for understanding the structure and dynamics in thin films and membranes. In the present work, we introduce fluorescence-interferometry, a method that combines standard reflected light thin film interferometry with simultaneous fluorescence measurements. We apply this method to the thinning dynamics and phase separation in free-standing inverse phospholipid bilayer films. The measurements were carried out using a standard fluorescence microscope using multichannel imaging and yielded subnanometer resolution, which is applied to optically measure the discrete thickness variations across phase-separated membranes.
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48
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Tran IC, Tunuguntla RH, Kim K, Lee JRI, Willey TM, Weiss TM, Noy A, van Buuren T. Structure of Carbon Nanotube Porins in Lipid Bilayers: An in Situ Small-Angle X-ray Scattering (SAXS) Study. NANO LETTERS 2016; 16:4019-4024. [PMID: 27322135 DOI: 10.1021/acs.nanolett.6b00466] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Carbon nanotube porins (CNTPs), small segments of carbon nanotubes capable of forming defined pores in lipid membranes, are important future components for bionanoelectronic devices as they could provide a robust analog of biological membrane channels. In order to control the incorporation of these CNT channels into lipid bilayers, it is important to understand the structure of the CNTPs before and after insertion into the lipid bilayer as well as the impact of such insertion on the bilayer structure. Here we employed a noninvasive in situ probe, small-angle X-ray scattering, to study the integration of CNT porins into dioleoylphosphatidylcholine bilayers. Our results show that CNTPs in solution are stabilized by a monolayer of lipid molecules wrapped around their outer surface. We also demonstrate that insertion of CNTPs into the lipid bilayer results in decreased bilayer thickness with the magnitude of this effect increasing with the concentration of CNTPs.
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Affiliation(s)
- Ich C Tran
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory , Livermore, California 94550, United States
| | - Ramya H Tunuguntla
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory , Livermore, California 94550, United States
| | - Kyunghoon Kim
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory , Livermore, California 94550, United States
| | - Jonathan R I Lee
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory , Livermore, California 94550, United States
| | - Trevor M Willey
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory , Livermore, California 94550, United States
| | - Thomas M Weiss
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Center , Menlo Park, California 94025, United States
| | - Aleksandr Noy
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory , Livermore, California 94550, United States
| | - Tony van Buuren
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory , Livermore, California 94550, United States
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49
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Kim S, Chang R. Structure, Dynamics, and Phase Behavior of DOPC/DSPC Mixture Membrane Systems: Molecular Dynamics Simulation Studies. B KOREAN CHEM SOC 2016. [DOI: 10.1002/bkcs.10827] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Seonghan Kim
- Department of Chemistry; Kwangwoon University; Seoul 01897 Republic of Korea
| | - Rakwoo Chang
- Department of Chemistry; Kwangwoon University; Seoul 01897 Republic of Korea
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50
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Usuda H, Hishida M, Yamamura Y, Saito K. Contrasting Effects of a Rigid Core and an Alkyl Chain in nCB on the Phase Behavior of Lipid Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:5966-5972. [PMID: 27219128 DOI: 10.1021/acs.langmuir.6b00774] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Molecules incorporated into biomembranes often bear both a core and an alkyl chain in a single molecule (e.g., sterols). To clarify the effects of these two parts of a molecule, the phase behavior of a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayer containing 4-n-alkyl-4'-cyanobiphenyl (nCB) (n = 0-8) was investigated. The trends of the main transition temperature (Tm) with respect to n and of the pretransition temperature (Tp) with respect to nCB content changed at n = 3. It was therefore suggested that the two parts of the molecule had opposing effects on the phase behavior of DPPC bilayers. The core appears to perturb molecular ordering in the gel phase and lowers Tm (like cholesterol), while alkyl chains appear to order the lipids in the gel phase and raise Tm (like n-alkanes). In addition, Tm exhibits the so-called odd-even effect based on the alkyl chain length of the minor component, nCB. Depending on the value of n, the variation in Tp was dependent on the additive content, although the pretransition was rarely observed at high contents.
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Affiliation(s)
- Hatsuho Usuda
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba , Tsukuba, Ibaraki 305-8571, Japan
| | - Mafumi Hishida
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba , Tsukuba, Ibaraki 305-8571, Japan
| | - Yasuhisa Yamamura
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba , Tsukuba, Ibaraki 305-8571, Japan
| | - Kazuya Saito
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba , Tsukuba, Ibaraki 305-8571, Japan
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