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McCarthy NLC, Chan CL, Mignini Urdaneta GECM, Liao Y, Law RV, Ces O, Seddon JM, Brooks NJ. The effect of hydrostatic pressure on lipid membrane lateral structure. Methods Enzymol 2024; 700:49-76. [PMID: 38971612 DOI: 10.1016/bs.mie.2024.03.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/08/2024]
Abstract
High pressure is both an environmental challenge to which deep sea biology has to adapt, and a highly sensitive thermodynamic tool that can be used to trigger structural changes in biological molecules and assemblies. Lipid membranes are amongst the most pressure sensitive biological assemblies and pressure can have a large influence on their structure and properties. In this chapter, we will explore the use of high pressure small angle X-ray diffraction and high pressure microscopy to measure and quantify changes in the lateral structure of lipid membranes under both equilibrium high pressure conditions and in response to pressure jumps.
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Affiliation(s)
| | - Chi L Chan
- Department of Chemistry, Imperial College London, London, United Kingdom
| | | | - Yifei Liao
- Department of Chemistry, Imperial College London, London, United Kingdom
| | - Robert V Law
- Department of Chemistry, Imperial College London, London, United Kingdom
| | - Oscar Ces
- Department of Chemistry, Imperial College London, London, United Kingdom
| | - John M Seddon
- Department of Chemistry, Imperial College London, London, United Kingdom
| | - Nicholas J Brooks
- Department of Chemistry, Imperial College London, London, United Kingdom.
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2
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Nixon-Abell J, Ruggeri FS, Qamar S, Herling TW, Czekalska MA, Shen Y, Wang G, King C, Fernandopulle MS, Sneideris T, Watson JL, Pillai VVS, Meadows W, Henderson JW, Chambers JE, Wagstaff JL, Williams SH, Coyle H, Lu Y, Zhang S, Marciniak SJ, Freund SMV, Derivery E, Ward ME, Vendruscolo M, Knowles TPJ, St George-Hyslop P. ANXA11 biomolecular condensates facilitate protein-lipid phase coupling on lysosomal membranes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.22.533832. [PMID: 36993242 PMCID: PMC10055329 DOI: 10.1101/2023.03.22.533832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Phase transitions of cellular proteins and lipids play a key role in governing the organisation and coordination of intracellular biology. The frequent juxtaposition of proteinaceous biomolecular condensates to cellular membranes raises the intriguing prospect that phase transitions in proteins and lipids could be co-regulated. Here we investigate this possibility in the ribonucleoprotein (RNP) granule-ANXA11-lysosome ensemble, where ANXA11 tethers RNP granule condensates to lysosomal membranes to enable their co-trafficking. We show that changes to the protein phase state within this system, driven by the low complexity ANXA11 N-terminus, induce a coupled phase state change in the lipids of the underlying membrane. We identify the ANXA11 interacting proteins ALG2 and CALC as potent regulators of ANXA11-based phase coupling and demonstrate their influence on the nanomechanical properties of the ANXA11-lysosome ensemble and its capacity to engage RNP granules. The phenomenon of protein-lipid phase coupling we observe within this system offers an important template to understand the numerous other examples across the cell whereby biomolecular condensates closely juxtapose cell membranes. GRAPHICAL ABSTRACT
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A Brief Review of FT-IR Spectroscopy Studies of Sphingolipids in Human Cells. BIOPHYSICA 2023. [DOI: 10.3390/biophysica3010011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
In recent years, sphingolipids have attracted significant attention due to their pivotal role in cellular functions and physiological diseases. A valuable tool for investigating the characteristics of sphingolipids can be represented via FT-IR spectroscopy, generally recognized as a very powerful technique that provides detailed biochemical information on the examined sample with the unique properties of sensitivity and accuracy. In the present paper, some fundamental aspects of sphingolipid components of human cells are summarized, and the most relevant articles devoted to the FT-IR spectroscopic studies of sphingolipids are revised. A short description of different FT-IR experimental approaches adopted for investigating sphingolipids is also given, with details about the most commonly used data analysis procedures. The present overview of FT-IR investigations, although not exhaustive, attests to the relevant role this vibrational technique has played in giving significant insight into many aspects of this fascinating class of lipids.
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4
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Knop JM, Mukherjee S, Jaworek MW, Kriegler S, Manisegaran M, Fetahaj Z, Ostermeier L, Oliva R, Gault S, Cockell CS, Winter R. Life in Multi-Extreme Environments: Brines, Osmotic and Hydrostatic Pressure─A Physicochemical View. Chem Rev 2023; 123:73-104. [PMID: 36260784 DOI: 10.1021/acs.chemrev.2c00491] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Elucidating the details of the formation, stability, interactions, and reactivity of biomolecular systems under extreme environmental conditions, including high salt concentrations in brines and high osmotic and high hydrostatic pressures, is of fundamental biological, astrobiological, and biotechnological importance. Bacteria and archaea are able to survive in the deep ocean or subsurface of Earth, where pressures of up to 1 kbar are reached. The deep subsurface of Mars may host high concentrations of ions in brines, such as perchlorates, but we know little about how these conditions and the resulting osmotic stress conditions would affect the habitability of such environments for cellular life. We discuss the combined effects of osmotic (salts, organic cosolvents) and hydrostatic pressures on the structure, stability, and reactivity of biomolecular systems, including membranes, proteins, and nucleic acids. To this end, a variety of biophysical techniques have been applied, including calorimetry, UV/vis, FTIR and fluorescence spectroscopy, and neutron and X-ray scattering, in conjunction with high pressure techniques. Knowledge of these effects is essential to our understanding of life exposed to such harsh conditions, and of the physical limits of life in general. Finally, we discuss strategies that not only help us understand the adaptive mechanisms of organisms that thrive in such harsh geological settings but could also have important ramifications in biotechnological and pharmaceutical applications.
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Affiliation(s)
- Jim-Marcel Knop
- Department of Chemistry and Chemical Biology, Biophysical Chemistry, TU Dortmund University, D-44221Dortmund, Germany
| | - Sanjib Mukherjee
- Department of Chemistry and Chemical Biology, Biophysical Chemistry, TU Dortmund University, D-44221Dortmund, Germany
| | - Michel W Jaworek
- Department of Chemistry and Chemical Biology, Biophysical Chemistry, TU Dortmund University, D-44221Dortmund, Germany
| | - Simon Kriegler
- Department of Chemistry and Chemical Biology, Biophysical Chemistry, TU Dortmund University, D-44221Dortmund, Germany
| | - Magiliny Manisegaran
- Department of Chemistry and Chemical Biology, Biophysical Chemistry, TU Dortmund University, D-44221Dortmund, Germany
| | - Zamira Fetahaj
- Department of Chemistry and Chemical Biology, Biophysical Chemistry, TU Dortmund University, D-44221Dortmund, Germany
| | - Lena Ostermeier
- Department of Chemistry and Chemical Biology, Biophysical Chemistry, TU Dortmund University, D-44221Dortmund, Germany
| | - Rosario Oliva
- Department of Chemistry and Chemical Biology, Biophysical Chemistry, TU Dortmund University, D-44221Dortmund, Germany.,Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, 80126Naples, Italy
| | - Stewart Gault
- UK Centre for Astrobiology, SUPA School of Physics and Astronomy, University of Edinburgh, James Clerk Maxwell Building, Peter Guthrie Tait Road, EH9 3FDEdinburgh, United Kingdom
| | - Charles S Cockell
- UK Centre for Astrobiology, SUPA School of Physics and Astronomy, University of Edinburgh, James Clerk Maxwell Building, Peter Guthrie Tait Road, EH9 3FDEdinburgh, United Kingdom
| | - Roland Winter
- Department of Chemistry and Chemical Biology, Biophysical Chemistry, TU Dortmund University, D-44221Dortmund, Germany
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Huang SK, Almurad O, Pejana RJ, Morrison ZA, Pandey A, Picard LP, Nitz M, Sljoka A, Prosser RS. Allosteric modulation of the adenosine A 2A receptor by cholesterol. eLife 2022; 11:e73901. [PMID: 34986091 PMCID: PMC8730723 DOI: 10.7554/elife.73901] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 12/23/2021] [Indexed: 12/18/2022] Open
Abstract
Cholesterol is a major component of the cell membrane and commonly regulates membrane protein function. Here, we investigate how cholesterol modulates the conformational equilibria and signaling of the adenosine A2A receptor (A2AR) in reconstituted phospholipid nanodiscs. This model system conveniently excludes possible effects arising from cholesterol-induced phase separation or receptor oligomerization and focuses on the question of allostery. GTP hydrolysis assays show that cholesterol weakly enhances the basal signaling of A2AR while decreasing the agonist EC50. Fluorine nuclear magnetic resonance (19F NMR) spectroscopy shows that this enhancement arises from an increase in the receptor's active state population and a G-protein-bound precoupled state. 19F NMR of fluorinated cholesterol analogs reveals transient interactions with A2AR, indicating a lack of high-affinity binding or direct allosteric modulation. The combined results suggest that the observed allosteric effects are largely indirect and originate from cholesterol-mediated changes in membrane properties, as shown by membrane fluidity measurements and high-pressure NMR.
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Affiliation(s)
- Shuya Kate Huang
- Department of Chemistry, University of TorontoTorontoCanada
- Department of Chemical and Physical Sciences, University of Toronto MississaugaMississaugaCanada
| | - Omar Almurad
- Department of Chemistry, University of TorontoTorontoCanada
- Department of Chemical and Physical Sciences, University of Toronto MississaugaMississaugaCanada
| | - Reizel J Pejana
- Department of Chemistry, University of TorontoTorontoCanada
- Department of Chemical and Physical Sciences, University of Toronto MississaugaMississaugaCanada
| | | | - Aditya Pandey
- Department of Chemistry, University of TorontoTorontoCanada
- Department of Chemical and Physical Sciences, University of Toronto MississaugaMississaugaCanada
| | - Louis-Philippe Picard
- Department of Chemistry, University of TorontoTorontoCanada
- Department of Chemical and Physical Sciences, University of Toronto MississaugaMississaugaCanada
| | - Mark Nitz
- Department of Chemistry, University of TorontoTorontoCanada
| | - Adnan Sljoka
- RIKEN Center for Advanced Intelligence ProjectTokyoJapan
- York University, Department of ChemistryTorontoCanada
| | - R Scott Prosser
- Department of Chemistry, University of TorontoTorontoCanada
- Department of Chemical and Physical Sciences, University of Toronto MississaugaMississaugaCanada
- Department of Biochemistry, University of TorontoTorontoCanada
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6
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Quemé-Peña M, Juhász T, Kohut G, Ricci M, Singh P, Szigyártó IC, Papp ZI, Fülöp L, Beke-Somfai T. Membrane Association Modes of Natural Anticancer Peptides: Mechanistic Details on Helicity, Orientation, and Surface Coverage. Int J Mol Sci 2021; 22:ijms22168613. [PMID: 34445319 PMCID: PMC8395313 DOI: 10.3390/ijms22168613] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/04/2021] [Accepted: 08/06/2021] [Indexed: 12/19/2022] Open
Abstract
Anticancer peptides (ACPs) could potentially offer many advantages over other cancer therapies. ACPs often target cell membranes, where their surface mechanism is coupled to a conformational change into helical structures. However, details on their binding are still unclear, which would be crucial to reach progress in connecting structural aspects to ACP action and to therapeutic developments. Here we investigated natural helical ACPs, Lasioglossin LL-III, Macropin 1, Temporin-La, FK-16, and LL-37, on model liposomes, and also on extracellular vesicles (EVs), with an outer leaflet composition similar to cancer cells. The combined simulations and experiments identified three distinct binding modes to the membranes. Firstly, a highly helical structure, lying mainly on the membrane surface; secondly, a similar, yet only partially helical structure with disordered regions; and thirdly, a helical monomeric form with a non-inserted perpendicular orientation relative to the membrane surface. The latter allows large swings of the helix while the N-terminal is anchored to the headgroup region. These results indicate that subtle differences in sequence and charge can result in altered binding modes. The first two modes could be part of the well-known carpet model mechanism, whereas the newly identified third mode could be an intermediate state, existing prior to membrane insertion.
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Affiliation(s)
- Mayra Quemé-Peña
- Biomolecular Self-Assembly Research Group, Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, H-1117 Budapest, Hungary; (M.Q.-P.); (G.K.); (M.R.); (P.S.); (I.C.S.)
- Hevesy György Ph.D. School of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter Sétány 1/A, H-1117 Budapest, Hungary
| | - Tünde Juhász
- Biomolecular Self-Assembly Research Group, Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, H-1117 Budapest, Hungary; (M.Q.-P.); (G.K.); (M.R.); (P.S.); (I.C.S.)
- Correspondence: (T.J.); (T.B.-S.)
| | - Gergely Kohut
- Biomolecular Self-Assembly Research Group, Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, H-1117 Budapest, Hungary; (M.Q.-P.); (G.K.); (M.R.); (P.S.); (I.C.S.)
- Hevesy György Ph.D. School of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter Sétány 1/A, H-1117 Budapest, Hungary
| | - Maria Ricci
- Biomolecular Self-Assembly Research Group, Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, H-1117 Budapest, Hungary; (M.Q.-P.); (G.K.); (M.R.); (P.S.); (I.C.S.)
| | - Priyanka Singh
- Biomolecular Self-Assembly Research Group, Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, H-1117 Budapest, Hungary; (M.Q.-P.); (G.K.); (M.R.); (P.S.); (I.C.S.)
- Hevesy György Ph.D. School of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter Sétány 1/A, H-1117 Budapest, Hungary
| | - Imola Cs. Szigyártó
- Biomolecular Self-Assembly Research Group, Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, H-1117 Budapest, Hungary; (M.Q.-P.); (G.K.); (M.R.); (P.S.); (I.C.S.)
| | - Zita I. Papp
- Department of Medical Chemistry, University of Szeged, Dóm tér 8, H-6720 Szeged, Hungary; (Z.I.P.); (L.F.)
| | - Lívia Fülöp
- Department of Medical Chemistry, University of Szeged, Dóm tér 8, H-6720 Szeged, Hungary; (Z.I.P.); (L.F.)
| | - Tamás Beke-Somfai
- Biomolecular Self-Assembly Research Group, Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, H-1117 Budapest, Hungary; (M.Q.-P.); (G.K.); (M.R.); (P.S.); (I.C.S.)
- Correspondence: (T.J.); (T.B.-S.)
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7
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Herzog M, Tiso T, Blank LM, Winter R. Interaction of rhamnolipids with model biomembranes of varying complexity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183431. [DOI: 10.1016/j.bbamem.2020.183431] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 07/26/2020] [Indexed: 12/25/2022]
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8
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Leung SSW, Brewer J, Bagatolli LA, Thewalt JL. Measuring molecular order for lipid membrane phase studies: Linear relationship between Laurdan generalized polarization and deuterium NMR order parameter. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:183053. [DOI: 10.1016/j.bbamem.2019.183053] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 07/27/2019] [Accepted: 08/21/2019] [Indexed: 01/03/2023]
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9
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Masukawa MK, Vequi-Suplicy CC, Duarte EL, Lamy MT. A closer look into laurdan as a probe to monitor cationic DODAB bilayers. J Photochem Photobiol A Chem 2019. [DOI: 10.1016/j.jphotochem.2019.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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10
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Small-Molecule Modulation of Lipid-Dependent Cellular Processes against Cancer: Fats on the Gunpoint. BIOMED RESEARCH INTERNATIONAL 2018; 2018:6437371. [PMID: 30186863 PMCID: PMC6114229 DOI: 10.1155/2018/6437371] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 07/22/2018] [Indexed: 12/27/2022]
Abstract
Lipid cell membrane composed of various distinct lipids and proteins act as a platform to assemble various signaling complexes regulating innumerous cellular processes which are strongly downregulated or altered in cancer cells emphasizing the still-underestimated critical function of lipid biomolecules in cancer initiation and progression. In this review, we outline the current understanding of how membrane lipids act as signaling hot spots by generating distinct membrane microdomains called rafts to initiate various cellular processes and their modulation in cancer phenotypes. We elucidate tangible drug targets and pathways all amenable to small-molecule perturbation. Ranging from targeting membrane rafts organization/reorganization to rewiring lipid metabolism and lipid sorting in cancer, the work summarized here represents critical intervention points being attempted for lipid-based anticancer therapy and future directions.
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11
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Inorganic mercury and cadmium induce rigidity in eukaryotic lipid extracts while mercury also ruptures red blood cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:710-717. [DOI: 10.1016/j.bbamem.2017.12.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 11/22/2017] [Accepted: 12/15/2017] [Indexed: 01/19/2023]
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12
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Hallmarks of Reversible Separation of Living, Unperturbed Cell Membranes into Two Liquid Phases. Biophys J 2018; 113:2425-2432. [PMID: 29211996 DOI: 10.1016/j.bpj.2017.09.029] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 09/15/2017] [Accepted: 09/22/2017] [Indexed: 01/04/2023] Open
Abstract
Controversy has long surrounded the question of whether spontaneous lateral demixing of membranes into coexisting liquid phases can organize proteins and lipids on micron scales within unperturbed, living cells. A clear answer hinges on observation of hallmarks of a reversible phase transition. Here, by directly imaging micron-scale membrane domains of yeast vacuoles both in vivo and cell free, we demonstrate that the domains arise through a phase separation mechanism. The domains are large, have smooth boundaries, and can merge quickly, consistent with fluid phases. Moreover, the domains disappear above a distinct miscibility transition temperature (Tmix) and reappear below Tmix, over multiple heating and cooling cycles. Hence, large-scale membrane organization in living cells under physiologically relevant conditions can be controlled by tuning a single thermodynamic parameter.
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Strohmeier A, Först G, Tauber P, Schubert R. Membrane/Water Partition Coefficients of Bile Salts Determined Using Laurdan as a Fluorescent Probe. Biophys J 2017; 111:1714-1723. [PMID: 27760358 DOI: 10.1016/j.bpj.2016.08.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 08/07/2016] [Accepted: 08/15/2016] [Indexed: 11/28/2022] Open
Abstract
The interaction of liposomal membranes composed of soybean phosphatidylcholine with the bile salts (BSs) cholate (Ch), glycocholate (GC), chenodeoxycholate (CDC), and glycochenodeoxycholate (GCDC) was studied. The BSs differed with regard to their lipophilicity, pKa values, and the size of their hydrophilic moiety. Their membrane interactions were investigated using Laurdan as a membrane-anchored fluorescent dye. The apparent membrane/water partition coefficient, D, at pH 7.4 was calculated from binding plots and compared with direct binding measurements using ultracentrifugation as a reference. The Laurdan-derived LogD values at pH 7.4 were found to be 2.10 and 2.25 for the trihydroxy BSs, i.e., Ch and GC, and 2.85 and 2.75 for the dihydroxy BSs, i.e., CDC and GCDC, respectively. For the membrane-associated glycine-conjugated GC and GCDC (pKa values of ∼3.9), no differences in the Laurdan spectra of the respective BS were found at pH 6.8, 7.4, and 8.2. Unconjugated Ch and CDC (pKa values of ∼5.0) showed pronounced differences at the three pH values. Furthermore, the kinetics of membrane adsorption and transbilayer movement differed between conjugated and unconjugated BSs as determined with Laurdan-labeled liposomes.
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Neves AR, Nunes C, Amenitsch H, Reis S. Resveratrol Interaction with Lipid Bilayers: A Synchrotron X-ray Scattering Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:12914-12922. [PMID: 27788010 DOI: 10.1021/acs.langmuir.6b03591] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Resveratrol belongs to the large group of biologically active polyphenol compounds, with several beneficial health effects including antioxidant activity, anti-inflammatory action, cardiovascular protection, neuroprotection, and cancer chemoprevention. In the present study, the possibility that the effects of resveratrol described above are caused by resveratrol membrane interactions and structural modifications of lipid bilayers is evaluated. In this context, it is possible that resveratrol interacts selectively with lipid domains present in biological membranes, thereby modulating the localization of the anchored proteins and controlling their intracellular cascades. This study was conducted in a synchrotron particle accelerator, where the influence of resveratrol in the structural organization of lipid domains in bilayers was investigated using small- and wide-angle X-ray scattering (SAXS and WAXS) techniques. Membrane mimetic systems composed of egg l-α-phosphatidylcholine (EPC), cholesterol (CHOL), and sphingomyelin (SM), with different molar ratios, were used to access the effects of resveratrol on the order and structure of the membrane. The results revealed that resveratrol induces phase separation, promoting the formation of lipid domains in EPC, EPC:CHOL [4:1], and EPC:CHOL:SM [1:1:1] bilayers, which brings some structural organization to membranes. Therefore, resveratrol controls lipid packing of bilayers by inducing the organization of lipid rafts. Moreover, the formation of lipid domains is important for modulating the activity of many receptors, transmembrane proteins, and enzymes whose activity depends on the structural organization of the membrane and on the presence or absence of these organized domains. This evidence can thereby explain the therapeutic effects of resveratrol.
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Affiliation(s)
- Ana Rute Neves
- UCIBIO, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto , Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Cláudia Nunes
- UCIBIO, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto , Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Heinz Amenitsch
- Institute of Inorganic Chemistry, Graz University of Technology , Stremayergasse 6/V, 8010 Graz, Austria
| | - Salette Reis
- UCIBIO, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto , Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
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15
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Kerek EM, Prenner EJ. Inorganic cadmium affects the fluidity and size of phospholipid based liposomes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:3169-3181. [DOI: 10.1016/j.bbamem.2016.10.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 09/21/2016] [Accepted: 10/06/2016] [Indexed: 12/13/2022]
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16
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Beddoes CM, Berge J, Bartenstein JE, Lange K, Smith AJ, Heenan RK, Briscoe WH. Hydrophilic nanoparticles stabilising mesophase curvature at low concentration but disrupting mesophase order at higher concentrations. SOFT MATTER 2016; 12:6049-6057. [PMID: 27340807 DOI: 10.1039/c6sm00393a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Using high pressure small angle X-ray scattering (HP-SAXS), we have studied monoolein (MO) mesophases at 18 wt% hydration in the presence of 10 nm silica nanoparticles (NPs) at NP-lipid number ratios (ν) of 1 × 10(-6), 1 × 10(-5) and 1 × 10(-4) over the pressure range 1-2700 bar and temperature range 20-60 °C. In the absence of the silica NPs, the pressure-temperature (p-T) phase diagram of monoolein exhibited inverse bicontinuous cubic gyroid (Q), lamellar alpha (Lα), and lamellar crystalline (Lc) phases. The addition of the NPs significantly altered the p-T phase diagram, changing the pressure (p) and the temperature (T) at which the transitions between these mesophases occurred. In particular, a strong NP concentration effect on the mesophase behaviour was observed. At low NP concentration, the p-T region pervaded by the Q phase and the Lα-Q mixture increased, and we attribute this behaviour to the NPs forming clusters at the mesophase domain boundaries, encouraging transition to the mesophase with a higher curvature. At high NP concentrations, the Q phase was no longer observed in the p-T phase diagram. Instead, it was dominated by the lamellar (L) phases until the transition to a fluid isotropic (FI) phase at 60 °C at low pressure. We speculate that NPs formed aggregates with a "chain of pearls" structure at the mesophase domain boundaries, hindering transitions to the mesophases with higher curvatures. These observations were supported by small angle neutron scattering (SANS) and scanning electron microscopy (SEM). Our results have implications to nanocomposite materials and nanoparticle cellular entry where the interactions between NPs and organised lipid structures are an important consideration.
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Affiliation(s)
- Charlotte M Beddoes
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK. and Bristol Centre for Functional Nanomaterials, Centre for Nanoscience and Quantum Information, Tyndall Avenue, Bristol BS8 1FD, UK
| | - Johanna Berge
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
| | - Julia E Bartenstein
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
| | - Kathrin Lange
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
| | - Andrew J Smith
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0QX, UK
| | | | - Wuge H Briscoe
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
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17
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Ramezanpour M, Leung SSW, Delgado-Magnero KH, Bashe BYM, Thewalt J, Tieleman DP. Computational and experimental approaches for investigating nanoparticle-based drug delivery systems. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1688-709. [PMID: 26930298 DOI: 10.1016/j.bbamem.2016.02.028] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 02/20/2016] [Accepted: 02/23/2016] [Indexed: 12/21/2022]
Abstract
Most therapeutic agents suffer from poor solubility, rapid clearance from the blood stream, a lack of targeting, and often poor translocation ability across cell membranes. Drug/gene delivery systems (DDSs) are capable of overcoming some of these barriers to enhance delivery of drugs to their right place of action, e.g. inside cancer cells. In this review, we focus on nanoparticles as DDSs. Complementary experimental and computational studies have enhanced our understanding of the mechanism of action of nanocarriers and their underlying interactions with drugs, biomembranes and other biological molecules. We review key biophysical aspects of DDSs and discuss how computer modeling can assist in rational design of DDSs with improved and optimized properties. We summarize commonly used experimental techniques for the study of DDSs. Then we review computational studies for several major categories of nanocarriers, including dendrimers and dendrons, polymer-, peptide-, nucleic acid-, lipid-, and carbon-based DDSs, and gold nanoparticles. This article is part of a Special Issue entitled: Membrane Proteins edited by J.C. Gumbart and Sergei Noskov.
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Affiliation(s)
- M Ramezanpour
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - S S W Leung
- Department of Physics, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - K H Delgado-Magnero
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - B Y M Bashe
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - J Thewalt
- Department of Physics, Simon Fraser University, Burnaby, BC V5A 1S6, Canada; Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - D P Tieleman
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
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18
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McCarthy NLC, Ces O, Law RV, Seddon JM, Brooks NJ. Separation of liquid domains in model membranes induced with high hydrostatic pressure. Chem Commun (Camb) 2016; 51:8675-8. [PMID: 25907808 DOI: 10.1039/c5cc02134k] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have imaged the formation of membrane microdomains immediately after their induction using a novel technology platform coupling high hydrostatic pressure to fluorescence microscopy. After formation, the ordered domains are small and highly dynamic. This will enhance links between model lipid assemblies and dynamic processes in cellular membranes.
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Affiliation(s)
- Nicola L C McCarthy
- Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
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19
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McCarthy N, Brooks N. Using High Pressure to Modulate Lateral Structuring in Model Lipid Membranes. ADVANCES IN BIOMEMBRANES AND LIPID SELF-ASSEMBLY 2016. [DOI: 10.1016/bs.abl.2016.04.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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20
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Miyoshi T, Kato S. Detailed Analysis of the Surface Area and Elasticity in the Saturated 1,2-Diacylphosphatidylcholine/Cholesterol Binary Monolayer System. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:9086-9096. [PMID: 26255826 DOI: 10.1021/acs.langmuir.5b01775] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The surface pressure-area (π-A) isotherms of DMPC, DPPC, and DSPC/cholesterol binary monolayers were systematically measured with great care to gain insight into the lateral molecular packing in these binary monolayer systems. The average molecular area A and the area elastic modulus C(s)⁻¹ at a given surface pressure were calculated as a function of cholesterol mole fraction x(chol). As a result, data reliable enough for the analysis of detailed phase behavior were obtained. We identified several characteristic phase regions and assigned the phase state in each region on the basis of the deviation of A(x(chol)) and C(s)⁻¹(x(chol)) from ideal additivity. We also estimated the partial molecular areas of DMPC, DPPC, DSPC, and cholesterol in the single-phase regions, where C(s)⁻¹(x(chol)) values fell on an ideal additivity curve. We found that the addition of cholesterol induces the formation of a highly condensed phase where the diacylphosphatidylcholine (diacyl PC) molecule has a surface area even smaller than that in the solid phase, irrespective of the surface pressure and the chain length of diacyl PC. Here, we call the cholesterol-induced condensed phase the CC phase. Furthermore, we demonstrated that the basic features of A(x(chol)) and C(s)⁻¹(x(chol)) profiles can be explained semiquantitatively by assuming the state of vicinity lipids surrounding sparsely distributed cholesterol molecules in the low x(chol) region as a third state of the diacyl PC molecule in addition to the states in the pure diacyl PC monolayer and in the CC phase.
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Affiliation(s)
- Tsubasa Miyoshi
- Department of Physics, Graduate School of Science and Technology, Kwansei Gakuin University , 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan
| | - Satoru Kato
- Department of Physics, Graduate School of Science and Technology, Kwansei Gakuin University , 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan
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21
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Nirmalanandhan VS, Hurren R, Cameron WD, Gronda M, Shamas-Din A, You L, Minden MD, Rocheleau JV, Schimmer AD. Increased pressure alters plasma membrane dynamics and renders acute myeloid leukemia cells resistant to daunorubicin. Haematologica 2015; 100:e406-8. [PMID: 26185171 DOI: 10.3324/haematol.2015.129866] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
| | - Rose Hurren
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON
| | - William D Cameron
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Marcela Gronda
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON
| | - Aisha Shamas-Din
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON
| | - Lidan You
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Mark D Minden
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON
| | - Jonathan V Rocheleau
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada Toronto General Research Institute, University Health Network, Toronto, ON, Canada
| | - Aaron D Schimmer
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON
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22
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Sacchi M, Balleza D, Vena G, Puia G, Facci P, Alessandrini A. Effect of neurosteroids on a model lipid bilayer including cholesterol: An Atomic Force Microscopy study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1258-67. [PMID: 25620773 DOI: 10.1016/j.bbamem.2015.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 12/18/2014] [Accepted: 01/02/2015] [Indexed: 12/20/2022]
Abstract
Amphiphilic molecules which have a biological effect on specific membrane proteins, could also affect lipid bilayer properties possibly resulting in a modulation of the overall membrane behavior. In light of this consideration, it is important to study the possible effects of amphiphilic molecule of pharmacological interest on model systems which recapitulate some of the main properties of the biological plasma membranes. In this work we studied the effect of a neurosteroid, Allopregnanolone (3α,5α-tetrahydroprogesterone or Allo), on a model bilayer composed by the ternary lipid mixture DOPC/bSM/chol. We chose ternary mixtures which present, at room temperature, a phase coexistence of liquid ordered (Lo) and liquid disordered (Ld) domains and which reside near to a critical point. We found that Allo, which is able to strongly partition in the lipid bilayer, induces a marked increase in the bilayer area and modifies the relative proportion of the two phases favoring the Ld phase. We also found that the neurosteroid shifts the miscibility temperature to higher values in a way similarly to what happens when the cholesterol concentration is decreased. Interestingly, an isoform of Allo, isoAllopregnanolone (3β,5α-tetrahydroprogesterone or isoAllo), known to inhibit the effects of Allo on GABAA receptors, has an opposite effect on the bilayer properties.
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Affiliation(s)
- Mattia Sacchi
- Dipartimento di Scienze Fisiche, Matematiche e Informatiche, Via Campi 213/A, 41125 Modena, Italy; CNR - Istituto Nanoscienze, S3, Via Campi 213/A, 41125 Modena, Italy
| | - Daniel Balleza
- CNR - Istituto Nanoscienze, S3, Via Campi 213/A, 41125 Modena, Italy
| | - Giulia Vena
- Dipartimento di Scienze della Vita, Università di Modena e Reggio Emilia, Via Campi 287, Modena 287, Italy
| | - Giulia Puia
- Dipartimento di Scienze della Vita, Università di Modena e Reggio Emilia, Via Campi 287, Modena 287, Italy
| | - Paolo Facci
- CNR - Istituto di Biofisica, Via De Marini 6, 16149 Genova, Italy
| | - Andrea Alessandrini
- Dipartimento di Scienze Fisiche, Matematiche e Informatiche, Via Campi 213/A, 41125 Modena, Italy; CNR - Istituto Nanoscienze, S3, Via Campi 213/A, 41125 Modena, Italy.
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23
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Abstract
We review the combined effect of temperature and pressure on the structure, dynamics and phase behavior of lipid bilayers, differing in chain length, headgroup structure and composition as revealed by thermodynamic, spectroscopic and scattering experiments. The effect of additives, such as ions, cholesterol, and anaesthetics is discussed as well. Our data include also reports on the effect of pressure on the lateral organization of heterogeneous lipid membranes and lipid extracts from cellular membranes, as well as the influence of peptide and protein incorporation on the pressure-dependent structure and phase behavior of lipid membranes. Moreover, the effects of pressure on membrane protein function are summarized. Finally, we introduce pressure as a kinetic variable for studying the kinetics of various lipid phase transformations.
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Affiliation(s)
- Roland Winter
- Physical Chemistry I - Biophysical Chemistry, TU Dortmund University, Otto-Hahn Str. 6, D-44227, Dortmund, Germany,
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24
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Seeliger J, Erwin N, Rosin C, Kahse M, Weise K, Winter R. Exploring the structure and phase behavior of plasma membrane vesicles under extreme environmental conditions. Phys Chem Chem Phys 2015; 17:7507-13. [DOI: 10.1039/c4cp05845c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A protocol was developed to generate GPMVs showing phase separation under ambient conditions and theirp,T-dependent phase behavior was studied.
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Affiliation(s)
- Janine Seeliger
- Physical Chemistry I – Biophysical Chemistry
- Department of Chemistry and Chemical Biology
- TU Dortmund University
- 44227 Dortmund
- Germany
| | - Nelli Erwin
- Physical Chemistry I – Biophysical Chemistry
- Department of Chemistry and Chemical Biology
- TU Dortmund University
- 44227 Dortmund
- Germany
| | - Christopher Rosin
- Physical Chemistry I – Biophysical Chemistry
- Department of Chemistry and Chemical Biology
- TU Dortmund University
- 44227 Dortmund
- Germany
| | - Marie Kahse
- Physical Chemistry I – Biophysical Chemistry
- Department of Chemistry and Chemical Biology
- TU Dortmund University
- 44227 Dortmund
- Germany
| | - Katrin Weise
- Physical Chemistry I – Biophysical Chemistry
- Department of Chemistry and Chemical Biology
- TU Dortmund University
- 44227 Dortmund
- Germany
| | - Roland Winter
- Physical Chemistry I – Biophysical Chemistry
- Department of Chemistry and Chemical Biology
- TU Dortmund University
- 44227 Dortmund
- Germany
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25
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Bilge D, Sahin I, Kazanci N, Severcan F. Interactions of tamoxifen with distearoyl phosphatidylcholine multilamellar vesicles: FTIR and DSC studies. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 130:250-256. [PMID: 24792199 DOI: 10.1016/j.saa.2014.04.027] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/06/2014] [Accepted: 04/06/2014] [Indexed: 06/03/2023]
Abstract
Interactions of a non-steroidal antiestrogen drug, tamoxifen (TAM), with distearoyl-sn-glycero-3-phosphatidylcholine (DSPC) multilamellar liposomes (MLVs) were investigated as a function of drug concentration (1-15 mol%) by using two noninvasive techniques, namely Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). FTIR spectroscopy results show that increasing TAM concentrations (except 1 mol%) increased the wavenumbers of the CH2 stretching modes, implying an disordering effect for DSPC MLVs both in the gel and liquid crystalline phases. The bandwidth values of the CH2 stretchings except for 1 mol% increased when TAM concentrations increased for DSPC liposomes, indicating an increase in the dynamics of liposomes. The CO stretching and PO2- antisymmetric double bond stretching bands were analyzed to study interactions of TAM with head groups of lipids. As the concentrations of TAM increased, dehydration occurred around these functional groups in the polar part of the lipids. The DSC studies on thermal properties of DSPC lipids indicate that TAM eliminated the pre transition, shifted the main phase transition to lower temperatures and broadened the phase transition curve of the liposomes.
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Affiliation(s)
- Duygu Bilge
- Department of Physics, Faculty of Science, Ege University, 35100 İzmir, Turkey
| | - Ipek Sahin
- Department of Physics, Faculty of Science, Ege University, 35100 İzmir, Turkey
| | - Nadide Kazanci
- Department of Physics, Faculty of Science, Ege University, 35100 İzmir, Turkey.
| | - Feride Severcan
- Department of Biological Sciences, Middle East Technical University, 06531 Ankara, Turkey
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26
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Zupancic E, Carreira AC, de Almeida RFM, Silva LC. Biophysical Implications of Sphingosine Accumulation in Membrane Properties at Neutral and Acidic pH. J Phys Chem B 2014; 118:4858-66. [DOI: 10.1021/jp501167f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Eva Zupancic
- iMed.UL
- Research Institute for Medicines and Pharmaceutical Sciences, Faculdade de Farmácia da Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - Ana C. Carreira
- iMed.UL
- Research Institute for Medicines and Pharmaceutical Sciences, Faculdade de Farmácia da Universidade de Lisboa, 1649-003 Lisboa, Portugal
- Centro
de Química e Bioquímica, DQB, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Rodrigo F. M. de Almeida
- Centro
de Química e Bioquímica, DQB, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Liana C. Silva
- iMed.UL
- Research Institute for Medicines and Pharmaceutical Sciences, Faculdade de Farmácia da Universidade de Lisboa, 1649-003 Lisboa, Portugal
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27
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Rahmani A, Knight C, Morrow MR. Response to hydrostatic pressure of bicellar dispersions containing an anionic lipid: pressure-induced interdigitation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:13481-13490. [PMID: 24116385 DOI: 10.1021/la4035694] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Bicellar dispersions of chain perdeuterated 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC-d54), 1,2-dimyristoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DMPG), and 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC), with molar ratios of 3:1:1, were studied using variable-pressure (2)H NMR spectroscopy at hydrostatic pressures up to 125 MPa. Upon warming of the dispersions, spectra at ambient pressure indicated a progressive coalescence from small bilayered disks undergoing isotropic reorientation to more extended micellar structures in which spectra indicated anisotropic reorientation and, under some conditions, magnetic orientation and finally to randomly oriented lamellae or multilamellar vesicles. Temperatures for the onsets of anisotropic reorientation and random lamellar orientation increased with pressure at rates of 0.22 and 0.15 °C/MPa, respectively. In the 3.5-T magnetic field used for this work, magnetic orientation within the intermediate phase was not observed at 83 MPa or higher pressures. Comparison of spectra obtained at fixed pressure showed significant asymmetry between behaviors upon warming and cooling. For samples of DMPC-d54/DMPG/DHPC (3:1:1), but not DMPC-d54/DHPC (4:1), a persistent interdigitated phase was formed after repeated cooling from high temperature at 83 MPa. This is likely a metastable phase and might reflect kinetic trapping of the short-chain lipid component, DHPC, in a nonequilibrium spatial distribution as temperature is lowered at high pressure. Bicellar dispersions typically behave differently upon warming and cooling, and these observations could provide some insight into the observed behaviors in such systems. This work also suggests the possibility of trapping bicellar dispersions in persistent nonequilibrium morphologies.
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Affiliation(s)
- Ashkan Rahmani
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland , St. John's, Newfoundland and Labrador, Canada A1B 3X7
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28
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FTIR spectroscopy study of the pressure-dependent behaviour of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1-palmitoyl-2-oleolyl-sn-glycero-3-phosphocholine (POPC) at low degrees of hydration. Chem Phys Lipids 2013; 170-171:33-40. [DOI: 10.1016/j.chemphyslip.2013.02.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 02/18/2013] [Accepted: 02/19/2013] [Indexed: 11/22/2022]
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29
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Ernst AM, Contreras FX, Thiele C, Wieland F, Brügger B. Mutual recognition of sphingolipid molecular species in membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2616-22. [DOI: 10.1016/j.bbamem.2012.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 06/04/2012] [Indexed: 01/11/2023]
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30
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Prades J, Funari SS, Gomez-Florit M, Vögler O, Barceló F. Effect of a 2-hydroxylated fatty acid on Cholesterol-rich membrane domains. Mol Membr Biol 2012; 29:333-43. [DOI: 10.3109/09687688.2012.705023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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31
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Cacas JL, Furt F, Le Guédard M, Schmitter JM, Buré C, Gerbeau-Pissot P, Moreau P, Bessoule JJ, Simon-Plas F, Mongrand S. Lipids of plant membrane rafts. Prog Lipid Res 2012; 51:272-99. [PMID: 22554527 DOI: 10.1016/j.plipres.2012.04.001] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lipids tend to organize in mono or bilayer phases in a hydrophilic environment. While they have long been thought to be incapable of coherent lateral segregation, it is now clear that spontaneous assembly of these compounds can confer microdomain organization beyond spontaneous fluidity. Membrane raft microdomains have the ability to influence spatiotemporal organization of protein complexes, thereby allowing regulation of cellular processes. In this review, we aim at summarizing briefly: (i) the history of raft discovery in animals and plants, (ii) the main findings about structural and signalling plant lipids involved in raft segregation, (iii) imaging of plant membrane domains, and their biochemical purification through detergent-insoluble membranes, as well as the existing debate on the topic. We also discuss the potential involvement of rafts in the regulation of plant physiological processes, and further discuss the prospects of future research into plant membrane rafts.
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Affiliation(s)
- Jean-Luc Cacas
- Laboratoire de Biogenèse Membranaire, UMR 5200 CNRS, Université de Bordeaux, 146 Rue Léo Saignat, 33076 Bordeaux, France
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32
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Structural organization of plasma membrane lipids isolated from cells cultured as a monolayer and in tissue-like conditions. J Colloid Interface Sci 2011; 359:202-9. [PMID: 21507411 DOI: 10.1016/j.jcis.2011.03.085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 03/28/2011] [Accepted: 03/29/2011] [Indexed: 11/20/2022]
Abstract
Complementary biophysical approaches were used to study the structural organization of plasma membrane lipids obtained from fibroblasts cultured as two-dimensional (2D) monolayer and in tissue-like three-dimensional (3D) conditions. Fluorescence microscopy experiments demonstrated different domain patterns for 2D and 3D plasma membrane lipid extracts. ESR demonstrated that 3D lipid extract is characterized with lower order parameter than 2D in the deep hydrophobic core of the lipid bilayer. Higher cholesterol and sphingomyelin content in 3D extract, known to increase the order in the glycerophospholipid matrix, was not able to compensate higher fatty acid polyunsaturation of the phospholipids. The interfacial region of the bilayer was probed by the fluorescent probe Laurdan. A higher general polarization value for 3D extract was measured. It is assigned to the increased content of sphingomyelin, cholesterol, phosphatidylethanolamine and phosphatidylserine in the 3D membranes. These results demonstrate that cells cultured under different conditions exhibit compositional heterogeneity of the constituent lipids which determine different structural organization of the membranes.
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33
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Applications of pressure perturbation calorimetry in biophysical studies. Biophys Chem 2011; 156:13-23. [DOI: 10.1016/j.bpc.2010.12.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 12/29/2010] [Accepted: 12/29/2010] [Indexed: 10/18/2022]
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34
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Pillman HA, Blanchard GJ. Consequences of Transient Heating on the Motional Dynamics of Cholesterol-Containing Phospholipid Vesicles. J Phys Chem B 2011; 115:3819-27. [DOI: 10.1021/jp111020j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Heather A. Pillman
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, United States
| | - G. J. Blanchard
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, United States
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35
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Kapoor S, Werkmüller A, Denter C, Zhai Y, Markgraf J, Weise K, Opitz N, Winter R. Temperature-pressure phase diagram of a heterogeneous anionic model biomembrane system: results from a combined calorimetry, spectroscopy and microscopy study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1187-95. [PMID: 21262194 DOI: 10.1016/j.bbamem.2011.01.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 01/17/2011] [Accepted: 01/19/2011] [Indexed: 01/13/2023]
Abstract
By using Fourier transform infrared (FT-IR) spectroscopy in combination with differential scanning calorimetry (DSC) coupled with pressure perturbation calorimetry (PPC), ultrasound velocimetry, Laurdan fluorescence spectroscopy, fluorescence microscopy and atomic force microscopy (AFM), the temperature and pressure dependent phase behavior of the five-component anionic model raft lipid mixture DOPC/DOPG/DPPC/DPPG/cholesterol (20:5:45:5:25 mol%) was investigated. A temperature range from 5 to 65 °C and a pressure range up to 16 kbar were covered to establish the temperature-pressure phase diagram of this heterogeneous model biomembrane system. Incorporation of 10-20 mol% PG still leads to liquid-ordered (l(o))-liquid-disordered (l(d)) phase coexistence regions over a wide range of temperatures and pressures. Compared to the corresponding neutral model raft mixture (DOPC/DPPC/Chol 25:50:25 mol%), the p,T-phase diagram is - as expected and in accordance with the Gibbs phase rule - more complex, the phase sequence as a function of temperature and pressure is largely similar, however. This anionic heterogeneous model membrane system will serve as a more realistic model biomembrane system to study protein interactions with anionic lipid bilayers displaying liquid-disordered/liquid-ordered domain coexistence over a wide range of the temperature-pressure plane, thus allowing also studies of biologically relevant systems encountered under extreme environmental conditions.
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Affiliation(s)
- Shobhna Kapoor
- Physical Chemistry I-Biophysical Chemistry, TU Dortmund University, Dortmund, Germany
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36
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Brooks NJ, Ces O, Templer RH, Seddon JM. Pressure effects on lipid membrane structure and dynamics. Chem Phys Lipids 2010; 164:89-98. [PMID: 21172328 DOI: 10.1016/j.chemphyslip.2010.12.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Revised: 12/07/2010] [Accepted: 12/09/2010] [Indexed: 11/30/2022]
Abstract
The effect of hydrostatic pressure on lipid structure and dynamics is highly important as a tool in biophysics and bio-technology, and in the biology of deep sea organisms. Despite its importance, high hydrostatic pressure remains significantly less utilised than other thermodynamic variables such as temperature and chemical composition. Here, we give an overview of some of the theoretical aspects which determine lipid behaviour under pressure and the techniques and technology available to study these effects. We also summarise several recent experiments which highlight the information available from these approaches.
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Affiliation(s)
- Nicholas J Brooks
- Membrane Biophysics Platform and Institute of Chemical Biology, Department of Chemistry, Imperial College London, South Kensington Campus, UK
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37
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Gohlke A, Triola G, Waldmann H, Winter R. Influence of the lipid anchor motif of N-ras on the interaction with lipid membranes: a surface plasmon resonance study. Biophys J 2010; 98:2226-35. [PMID: 20483331 DOI: 10.1016/j.bpj.2010.02.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 01/30/2010] [Accepted: 02/02/2010] [Indexed: 10/19/2022] Open
Abstract
Ras GTPases play a crucial role in signal transduction cascades involved in cell differentiation and proliferation, and membrane binding is essential for their proper function. To determine the influence of the nature of the lipid anchor motif and the difference between the active (GTP) and inactive (GDP) forms of N-Ras on partitioning and localization in the lipid membrane, five different N-Ras constructs with different lipid anchors and nucleotide loading (Far/Far (GDP), HD/Far (GDP), HD/HD (GDP), Far (GDP), and HD/Far (GppNHp)) were synthesized. Using the surface plasmon resonance technique, we were able to follow the insertion and dissociation process of the lipidated proteins into and out of model membranes consisting of pure liquid-ordered (l(o)) or liquid-disordered (l(d)) phase and a heterogeneous two-phase mixture, i.e., a raft mixture with l(o) + l(d) phase coexistence. In addition, we examined the influence of negatively charged headgroups and stored curvature elastic stress on the binding properties of the lipidated N-Ras proteins. In most cases, significant differences were found for the various anchor motifs. In general, N-Ras proteins insert preferentially into a fluidlike, rather than a rigid, ordered lipid bilayer environment. Electrostatic interactions with lipid headgroups or stored curvature elastic stress of the membrane seem to have no drastic effect on the binding and dissociation processes of the lipidated proteins. The monofarnesylated N-Ras exhibits generally the highest association rate and fastest dissociation process in fluidlike membranes. Double lipidation, especially including farnesylation, of the protein leads to drastically reduced initial binding rates but strong final association. The change in the nucleotide loading of the natural N-Ras HD/Far induces a slightly different binding and dissociation kinetics, as well as stability of association, and seems to influence the tendency to segregate laterally in the membrane plane. The GDP-bound inactive form of N-Ras with an HD/Far anchor shows stronger membrane association, which might be due to a more pronounced tendency to self-assemble in the membrane matrix than is seen with the active GTP-bound form.
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Affiliation(s)
- Andrea Gohlke
- Faculty of Chemistry, Physical Chemistry I-Biophysical Chemistry, Technische Universität Dortmund, Dortmund, Germany
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Lopes S, Neves CS, Eaton P, Gameiro P. Cardiolipin, a key component to mimic the E. coli bacterial membrane in model systems revealed by dynamic light scattering and steady-state fluorescence anisotropy. Anal Bioanal Chem 2010; 398:1357-66. [PMID: 20680614 DOI: 10.1007/s00216-010-4028-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 07/11/2010] [Accepted: 07/12/2010] [Indexed: 12/01/2022]
Abstract
The phase transition temperatures of several lipidic systems were determined using two different techniques: dynamic light scattering (DLS) and steady-state fluorescence anisotropy, using two fluorescent probes that report different membrane regions (TMA-DPH and DPH). Atomic force microscopy (AFM) was used as a complementary technique to characterize different lipid model systems under study. The systems were chosen due to the increased interest in bacterial membrane studies due to the problem of antibiotic drug resistance. The simpler models studied comprised of mixtures of POPE and POPG lipids, which form a commonly used model system for Escherichia coli membranes. Given the important role of cardiolipin (CL) in natural membranes, a ternary model system, POPE/POPG/CL, was then considered. The results obtained in these mimetic systems were compared with those obtained for the natural systems E. coli polar and total lipid extract. DLS and fluorescence anisotropy are not commonly used to study lipid phase transitions, but it was shown that they can give useful information about the thermotropic behaviors of model systems for bacterial membranes. These two techniques provided very similar results, validating their use as methods to measure phase transitions in lipid model systems. The temperature transitions obtained from these two very different techniques and the AFM results clearly show that cardiolipin is a fundamental component to mimic bacteria membranes. The results suggest that the less commonly used ternary system is a considerably better mimic for natural E. coli membranes than binary lipid mixture.
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Affiliation(s)
- S Lopes
- Requimte, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007, Porto, Portugal
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39
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Roche Y, Klymchenko AS, Gerbeau-Pissot P, Gervais P, Mély Y, Simon-Plas F, Perrier-Cornet JM. Behavior of plant plasma membranes under hydrostatic pressure as monitored by fluorescent environment-sensitive probes. BIOCHIMICA ET BIOPHYSICA ACTA 2010; 1798:1601-7. [PMID: 20381451 DOI: 10.1016/j.bbamem.2010.03.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Revised: 03/29/2010] [Accepted: 03/31/2010] [Indexed: 01/25/2023]
Abstract
We monitored the behavior of plasma membrane (PM) isolated from tobacco cells (BY-2) under hydrostatic pressures up to 3.5kbar at 30 degrees C, by steady-state fluorescence spectroscopy using the newly introduced environment-sensitive probe F2N12S and also Laurdan and di-4-ANEPPDHQ. The consequences of sterol depletion by methyl-beta-cyclodextrin were also studied. We found that application of hydrostatic pressure led to a marked decrease of hydration as probed by F2N12S and to an increase of the generalized polarization excitation (GPex) of Laurdan. We observed that the hydration effect of sterol depletion was maximal between 1 and 1.5 kbar but was much less important at higher pressures (above 2 kbar) where both parameters reached a plateau value. The presence of a highly dehydrated gel state, insensitive to the sterol content, was thus proposed above 2.5 kbar. However, the F2N12S polarity parameter and the di-4-ANEPPDHQ intensity ratio showed strong effect on sterol depletion, even at very high pressures (2.5-3.5 kbar), and supported the ability of sterols to modify the electrostatic properties of membrane, notably its dipole potential, in a highly dehydrated gel phase. We thus suggested that BY-2 PM undergoes a complex phase behavior in response to the hydrostatic pressure and we also emphasized the role of phytosterols to regulate the effects of high hydrostatic pressure on plant PM.
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Affiliation(s)
- Yann Roche
- Laboratoire Plantes-Microbe-Environnement, UMR INRA 1088/CNRS 5184/Université de Bourgogne, Dijon, France
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40
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Zhu X, Gaus K, Lu Y, Magenau A, Truscott RJW, Mitchell TW. α- and β-crystallins modulate the head group order of human lens membranes during aging. Invest Ophthalmol Vis Sci 2010; 51:5162-7. [PMID: 20484582 DOI: 10.1167/iovs.09-4947] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To examine the physical properties of human lens cell membranes as a function of age. METHODS The environment of the phospholipid head groups in fiber cell membranes from human lenses, aged 22 to 83 years, was assessed with Laurdan and two-photon confocal microscopy. The effect of mild thermal stress on head group order was studied with lens pairs in which one intact lens was incubated at 50 °C. Dihydrosphingomyelin vesicles were preloaded with Laurdan, α-, β-, or γ-crystallin was added, and surface fluidity was determined. RESULTS The membrane head group environment became more fluid with age as indicated by increased water penetration. Furthermore, these changes could be replicated simply by exposing intact human lenses to mild thermal stress; conditions which decreased the concentration of soluble α- and β-crystallins. Vesicle binding experiments showed that α- and β-, but not γ-, crystallins markedly affected head group order. CONCLUSIONS The physical properties of cell membranes in the lens nucleus change substantially with age, and α- and β-crystallins may modulate this effect. β-Crystallins may therefore play a role in lens cells, and cells of other tissues, apart from being simple structural proteins. Age-dependent loss of these crystallins may affect membrane integrity and contribute to the dysfunction of lenses in older people.
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Affiliation(s)
- Xiangjia Zhu
- Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, China
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41
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Krivanek R, Jeworrek C, Czeslik C, Winter R. Composition Fluctuations in Phospholipid-Sterol Vesicles – a Small-angle Neutron Scattering Study. ACTA ACUST UNITED AC 2009. [DOI: 10.1524/zpch.2008.5433] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
Sterols regulate biological processes and sustain the domain structure of cellular membranes. While cholesterol is the major sterol of vertebrates, ergosterol plays a key role in fungal membranes. In this study, small-angle neutron scattering in combination with the H/D contrast variation technique was employed to probe the lateral compositional organization in dipalmitoyl-phosphatidylcholine/ergosterol (DPPC/erg) model membranes over the temperature range from 26 to 78 °C. In addition, small-angle X-ray scattering and calorimetric measurements were carried out to characterize the phase behavior of this system in the temperature interval covered. The SANS measurements clearly demonstrate the absence of critical-point-like composition fluctuations at the temperature where the liquid-ordered/liquid-disordered (lo/ld) two-phase region closes and gives way to the all-fluid phase. Furthermore, no scattering due to large-scale composition fluctuations has been found in the whole lo+ld two-phase region of the system. It is concluded that this binary phospholipid-sterol mixture in the lo+ld coexistence region exhibits a homogeneous membrane with fluctuating nano-scale domains rather than a macroscopically separated two-phase coexistence region as observed for ternary phospholipid-sterol mixtures. Such small domains are expected to have particular properties like an increased line energy, a spontaneous curvature and limited lifetimes, which will probably also prevail for the small raft-like domains in cellular membranes.
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Affiliation(s)
| | | | - Claus Czeslik
- Universität Dortmund, Physikalische Chemie I, Dortmund, Deutschland
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42
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Tessier C, Staneva G, Trugnan G, Wolf C, Nuss P. Liquid-liquid immiscibility under non-equilibrium conditions in a model membrane: an X-ray synchrotron study. Colloids Surf B Biointerfaces 2009; 74:293-7. [PMID: 19720510 DOI: 10.1016/j.colsurfb.2009.07.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Revised: 05/13/2009] [Accepted: 07/23/2009] [Indexed: 10/20/2022]
Abstract
Several non-random lipid mixtures have been proposed as models of lipid plasma membrane, as they mimic the ability of biomembranes to form lateral domains. Biological membranes are characterised by a succession of localised transient steady-state lipid organisations rather than stable equilibria. This suggests that several quasi at-equilibrium lipid organisations may exist at different times in the same local patch of membranes. Identification of the conditions which can mimic heterogeneous dynamic membrane states in a lipid membrane model is a challenge. This is of particular importance as the lateral organisation of lipids mixtures in fully equilibrated samples may differ from the arrangement found in quasi at-equilibrium conditions. To address this issue, we have performed a real-time synchrotron X-ray diffraction study in ternary mixtures of egg-phosphatidylcholine/egg-sphingomyelin and cholesterol using a 0.5 degrees C/15 s step within a 20-50-20 degrees C thermal cycle. In the present study, all ternary mixtures displayed lamellar phase separation. A d-spacing value was observed reversibly during the heating and cooling scan for each of the two coexisting phases. In mixtures with a cholesterol concentration from 20 to 50 mol%, a liquid-ordered (Lo) and liquid-disordered (Ld) phase separation was observed in the 20-50 degrees C thermal range. These results are discussed in terms of a specific interaction between lipid molecular aggregates.
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Affiliation(s)
- Cedric Tessier
- Universite Pierre et Marie Curie Paris 6, Laboratoire de spectrometrie de masse, APHP, CHU St. Antoine, 27, rue Chaligny, 75012 Paris, France.
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Chen XB, Shi HJ, Niu LS. Numerical study of the phase separation in binary lipid membrane containing protein inclusions under stationary shear flow. J Biomech 2009; 42:603-13. [PMID: 19217626 DOI: 10.1016/j.jbiomech.2008.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2008] [Revised: 11/09/2008] [Accepted: 12/10/2008] [Indexed: 10/21/2022]
Abstract
The phase separation of lipids is believed to be responsible for the formation of lipid rafts in biological cell membrane. In the present work, a continuum model and a particle model are constructed to study the phase separation in binary lipid membrane containing inclusions under stationary shear flow. In each model, employing the cell dynamical system (CDS) approach, the kinetic equations of the confusion-advection process are numerically solved. Snapshot figures of the phase morphology are performed to intuitively display such phase evolving process. Considering the effects from both the inclusions and the shear flow, the time growth law of the characteristic domain size is discussed.
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Affiliation(s)
- Xiao-Bo Chen
- Key Laboratory of Failure Mechanics, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, PR China
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44
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Membrane lipid domains and rafts: current applications of fluorescence lifetime spectroscopy and imaging. Chem Phys Lipids 2009; 157:61-77. [DOI: 10.1016/j.chemphyslip.2008.07.011] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Accepted: 07/24/2008] [Indexed: 11/30/2022]
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45
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Potekhin S, Senin A, Abdurakhmanov N, Khusainova R. High pressure effect on the main transition from the ripple gel P′β phase to the liquid crystal (Lα) phase in dipalmitoylphosphatidylcholine. Microcalorimetric study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:2588-93. [DOI: 10.1016/j.bbamem.2008.08.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Revised: 07/31/2008] [Accepted: 08/04/2008] [Indexed: 11/30/2022]
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Jeworrek C, Pühse M, Winter R. X-ray kinematography of phase transformations of three-component lipid mixtures: a time-resolved synchrotron X-ray scattering study using the pressure-jump relaxation technique. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:11851-11859. [PMID: 18767826 DOI: 10.1021/la801947v] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
By using the pressure-jump relaxation technique in combination with time-resolved synchrotron small-angle X-ray diffraction (TRSAXS), the kinetics of lipid phase transformations of ternary lipid mixtures serving as model systems of heterogeneous raftlike membranes were investigated. To this end, we first established the temperature-pressure phase diagram of a model lipid raft mixture, 1,2-dioleoyl- sn-glycero-3-phosphatidylcholine (DOPC)/1,2-dipalmitoyl- sn-glycero-3-phosphatidylcholine (DPPC)/cholesterol (1:2:1), using Fourier transform infrared spectroscopy and SAXS, covering the pressure range from 1 bar to 10 kbar at temperatures in the range from 7 to 80 degrees C. We then studied the kinetics of interlamellar phase transitions of the ternary lipid system involving transitions from the fluidlike (liquid-disordered, l d) phase to the liquid-ordered (l o)/liquid-disordered (l d) two-phase coexistence region as well as between the two- and three-phase coexistence regions of the system, where also solid-ordered phases (s o) are involved. The phase transition from the all-fluid l d phase to the l o+l d two-phase coexistence region turns out to be rather rapid. Phases appear or disappear within the 25 ms time resolution of the technique, followed by a slow lattice relaxation process, which, depending on the pressure-jump amplitude, takes several seconds. Contrary to many one-component phospholipid phase transitions, the kinetics of the l d <--> l o+l d transition follows a similar time scale and mechanism for the pressurization and depressurization direction. A similar behavior is observed for the phase transition kinetics of the s o+l o+l d <--> l o+l d transformation and even for the s o+l o+l d <--> l d transformation, jumping across the l o+l d two-phase region. All transitions are fully reversible, and no intermediate states are populated. As indicated by the complex relaxation profiles observed, the overall rates observed seem to reflect the effect of coupling of various dynamical processes through the transformation, involving fast conformational changes in the sub-millisecond time regime and slow relaxation of the lattices growing, probably being largely controlled by the transport and redistribution of water into and in the new phases of the multilamellar vesicle assemblies.
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Affiliation(s)
- Christoph Jeworrek
- Dortmund University of Technology, Faculty of Chemistry, Physical Chemistry I - Biophysical Chemistry, Otto-Hahn-Strasse 6, D-44227 Dortmund, Germany
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Influence of high pressure on the dimerization of ToxR, a protein involved in bacterial signal transduction. Appl Environ Microbiol 2008; 74:7821-3. [PMID: 18931287 DOI: 10.1128/aem.02028-08] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
High hydrostatic pressure (HHP) is suggested to influence the structure and function of membranes and/or integrated proteins. We demonstrate for the first time HHP-induced dimer dissociation of membrane proteins in vivo with Vibrio cholerae ToxR variants in Escherichia coli reporter strains carrying ctx::lacZ fusions. Dimerization ceased at 20 to 50 MPa depending on the nature of the transmembrane segments rather than on changes in the ToxR lipid bilayer environment.
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Periasamy N, Teichert H, Weise K, Vogel RF, Winter R. Effects of temperature and pressure on the lateral organization of model membranes with functionally reconstituted multidrug transporter LmrA. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1788:390-401. [PMID: 18983816 DOI: 10.1016/j.bbamem.2008.09.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Revised: 09/19/2008] [Accepted: 09/24/2008] [Indexed: 11/29/2022]
Abstract
To contribute to the understanding of membrane protein function upon application of pressure, we investigated the influence of hydrostatic pressure on the conformational order and phase behavior of the multidrug transporter LmrA in biomembrane systems. To this end, the membrane protein was reconstituted into various lipid bilayer systems of different chain length, conformation, phase state and heterogeneity, including raft model mixtures as well as some natural lipid extracts. In the first step, we determined the temperature stability of the protein itself and verified its reconstitution into the lipid bilayer systems using CD spectroscopic and AFM measurements, respectively. Then, to yield information on the temperature and pressure dependent conformation and phase state of the lipid bilayer systems, generalized polarization values by the Laurdan fluorescence technique were determined, which report on the conformation and phase state of the lipid bilayer system. The temperature-dependent measurements were carried out in the temperature range 5-70 degrees C, and the pressure dependent measurements were performed in the range 1-200 MPa. The data show that the effect of the LmrA reconstitution on the conformation and phase state of the lipid matrix depends on the fluidity and hydrophobic matching conditions of the lipid system. The effect is most pronounced for fluid DMPC and DMPC with low cholesterol levels, but minor for longer-chain fluid phospholipids such as DOPC and model raft mixtures such as DOPC/DPPC/cholesterol. The latter have the additional advantage of using lipid sorting to avoid substantial hydrophobic mismatch. Notably, the most drastic effect was observed for the neutral/glycolipid natural lipid mixture. In this case, the impact of LmrA incorporation on the increase of the conformational order of the lipid membrane was most pronounced. As a consequence, the membrane reaches a mechanical stability which makes it very insensitive to application of pressures as high as 200 MPa. The results are correlated with the functional properties of LmrA in these various lipid environments and upon application of high hydrostatic pressure and are discussed in the context of other work on pressure effects on membrane protein systems.
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Affiliation(s)
- Nagarajan Periasamy
- Dortmund University of Technology, Physical Chemistry I - Biophysical Chemistry, D-44227 Dortmund, Germany
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Ausili A, Torrecillas A, Aranda FJ, Mollinedo F, Gajate C, Corbalán-García S, de Godos A, Gómez-Fernández JC. Edelfosine is incorporated into rafts and alters their organization. J Phys Chem B 2008; 112:11643-54. [PMID: 18712919 DOI: 10.1021/jp802165n] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The effect of edelfosine (1- O-octadecyl-2- O-methyl-rac-glycero-3-phosphocholine or ET-18-OCH3) on model membranes containing 1-palmitoyl-2-oleoyl- sn-glycero-3-phosphocholine/sphingomyelin/cholesterol (POPC/SM/cholesterol) was studied by several physical techniques. The sample POPC/SM (1:1 molar ratio) showed a broad phase transition as seen by DSC, X-ray diffraction, and 2H NMR. The addition of edelfosine to this sample produced isotropic structures at temperatures above the phase transition, as seen by 2H NMR and by 31P NMR. When cholesterol was added to give a POPC/SM/cholesterol (at a molar ratio 1:1:1), no transition was observed by DSC nor X-ray diffraction, and 2H NMR indicated the presence of a liquid ordered phase. The addition of 10 mol % edelfosine increased the thickness of the membrane as seen by X-ray diffraction and led to bigger differences in the values of the molecular order of the membrane detected at high and low temperatures, as detected through the M 1 first spectral moment from 2H NMR. These differences were even greater when 20 mol % edelfosine was added, and a transition was now clearly visible by DSC. In addition, a gel phase was clearly indicated by X-ray diffraction at low temperatures. The same technique pointed to greater membrane thickness in this mixture and to the appearance of a second membrane structure, indicating the formation of two separated phases in the presence of edelfosine. All of these data strongly suggest that edelfosine associating with cholesterol alter the phase status present in a POPC/SM/cholesterol (1:1:1 molar ratio) mixture, which is reputed to be a model of a raft structure. However, cell experiments showed that edelfosine colocalizes in vivo with rafts and that it may reach concentrations higher than 20 mol % of total lipid, indicating that the concentrations used in the biophysical experiments were within what can be expected in a cell membrane. The conclusion is that molecular ways of action of edelfosine in cells may involve the modification of the structure of rafts.
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Affiliation(s)
- Alessio Ausili
- Departamento de Bioquimica y Biologia Molecular A, Facultad de Veterinaria, Universidad de Murcia, Apartado de Correos 4021, Murcia, Spain
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Chen XB, Niu LS, Shi HJ. Numerical simulation of the phase separation in binary lipid membrane under the effect of stationary shear flow. Biophys Chem 2008; 135:84-94. [DOI: 10.1016/j.bpc.2008.03.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2008] [Revised: 03/26/2008] [Accepted: 03/26/2008] [Indexed: 01/08/2023]
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