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Yu C, Richly M, Hoang TT, El Beheiry M, Türkcan S, Masson JB, Alexandrou A, Bouzigues CI. Confinement energy landscape classification reveals membrane receptor nano-organization mechanisms. Biophys J 2024; 123:1882-1895. [PMID: 38845200 PMCID: PMC11267427 DOI: 10.1016/j.bpj.2024.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 03/01/2024] [Accepted: 06/03/2024] [Indexed: 06/22/2024] Open
Abstract
The cell membrane organization has an essential functional role through the control of membrane receptor confinement in micro- or nanodomains. Several mechanisms have been proposed to account for these properties, although some features have remained controversial, notably the nature, size, and stability of cholesterol- and sphingolipid-rich domains or lipid rafts. Here, we probed the effective energy landscape acting on single-nanoparticle-labeled membrane receptors confined in raft nanodomains- epidermal growth factor receptor (EGFR), Clostridium perfringens ε-toxin receptor (CPεTR), and Clostridium septicum α-toxin receptor (CSαTR)-and compared it with hop-diffusing transferrin receptors. By establishing a new analysis pipeline combining Bayesian inference, decision trees, and clustering approaches, we systematically classified single-protein trajectories according to the type of effective confining energy landscape. This revealed the existence of only two distinct organization modalities: confinement in a quadratic energy landscape for EGFR, CPεTR, and CSαTR (A), and free diffusion in confinement domains resulting from the steric hindrance due to F-actin barriers for transferrin receptor (B). The further characterization of effective confinement energy landscapes by Bayesian inference revealed the role of interactions with the domain environment in cholesterol- and sphingolipid-rich domains with (EGFR) or without (CPεTR and CSαTR) interactions with F-actin to regulate the confinement energy depth. These two distinct mechanisms result in the same organization type (A). We revealed that the apparent domain sizes for these receptor trajectories resulted from Brownian exploration of the energy landscape in a steady-state-like regime at a common effective temperature, independently of the underlying molecular mechanisms. These results highlight that confinement domains may be adequately described as interaction hotspots rather than rafts with abrupt domain boundaries. Altogether, these results support a new model for functional receptor confinement in membrane nanodomains and pave the way to the constitution of an atlas of membrane protein organization.
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Affiliation(s)
- Chao Yu
- Laboratoire Optique et Biosciences, CNRS UMR74645, Inserm U1182, Ecole Polytechnique, Institut Polytechnique Paris, Palaiseau, France
| | - Maximilian Richly
- Laboratoire Optique et Biosciences, CNRS UMR74645, Inserm U1182, Ecole Polytechnique, Institut Polytechnique Paris, Palaiseau, France
| | - Thi Thuy Hoang
- Laboratoire Optique et Biosciences, CNRS UMR74645, Inserm U1182, Ecole Polytechnique, Institut Polytechnique Paris, Palaiseau, France
| | - Mohammed El Beheiry
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Decision and Bayesian Computation, Paris, France; Épiméthée, INRIA, Paris, France
| | - Silvan Türkcan
- Laboratoire Optique et Biosciences, CNRS UMR74645, Inserm U1182, Ecole Polytechnique, Institut Polytechnique Paris, Palaiseau, France
| | - Jean-Baptiste Masson
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Decision and Bayesian Computation, Paris, France; Épiméthée, INRIA, Paris, France
| | - Antigoni Alexandrou
- Laboratoire Optique et Biosciences, CNRS UMR74645, Inserm U1182, Ecole Polytechnique, Institut Polytechnique Paris, Palaiseau, France
| | - Cedric I Bouzigues
- Laboratoire Optique et Biosciences, CNRS UMR74645, Inserm U1182, Ecole Polytechnique, Institut Polytechnique Paris, Palaiseau, France.
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2
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Fa K, Liu H, Li Z, Gong H, Petkov J, Ren Lu J. Acyl Chain Length Tuning Improves Antimicrobial Potency and Biocompatibility of Short Designed Lipopeptides. J Colloid Interface Sci 2022; 630:911-923. [DOI: 10.1016/j.jcis.2022.10.114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 10/16/2022] [Accepted: 10/22/2022] [Indexed: 11/06/2022]
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3
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Benedetto A, Kelley EG. Absorption of the [bmim][Cl] Ionic Liquid in DMPC Lipid Bilayers across Their Gel, Ripple, and Fluid Phases. J Phys Chem B 2022; 126:3309-3318. [PMID: 35472281 PMCID: PMC9082605 DOI: 10.1021/acs.jpcb.2c00710] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 04/11/2022] [Indexed: 12/19/2022]
Abstract
Lipid bilayers are a key component of cell membranes and play a crucial role in life and in bio-nanotechnology. As a result, controlling their physicochemical properties holds the promise of effective therapeutic strategies. Ionic liquids (ILs)─a vast class of complex organic electrolytes─have shown a high degree of affinity with lipid bilayers and can be exploited in this context. However, the chemical physics of IL absorption and partitioning into lipid bilayers is yet to be fully understood. This work focuses on the absorption of the model IL [bmim][Cl] into 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayers across their gel, ripple, and fluid phases. Here, by small-angle neutron scattering, we show that (i) the IL cations are absorbed in the lipid bilayer in all its thermodynamic phases and (ii) the amount of IL inserted into the lipid phase increased with increasing temperature, changing from three to four IL cations per 10 lipids with increasing temperature from 10 °C in the gel phase to 40 °C in the liquid phase, respectively. An explicative hypothesis, based on the entropy gain coming from the IL hydration water, is presented to explain the observed temperature trend. The ability to control IL absorption with temperature can be used as a handle to tune the effect of ILs on biomembranes and can be exploited in bio-nanotechnological applications.
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Affiliation(s)
- Antonio Benedetto
- Department
of Science, University of Roma Tre, 00146 Rome, Italy
- School
of Physics, and Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
- Laboratory
for Neutron Scattering, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Elizabeth G. Kelley
- NIST
Center for Neutron Research, National Institute
of Standards and Technology, Gaithersburg, Maryland 20899, United States
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4
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Mkam Tsengam IK, Omarova M, Kelley EG, McCormick A, Bothun GD, Raghavan SR, John VT. Transformation of Lipid Vesicles into Micelles by Adding Nonionic Surfactants: Elucidating the Structural Pathway and the Intermediate Structures. J Phys Chem B 2022; 126:2208-2216. [PMID: 35286100 PMCID: PMC8958590 DOI: 10.1021/acs.jpcb.1c09685] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 03/01/2022] [Indexed: 11/28/2022]
Abstract
The phospholipid lecithin (L) and the nonionic surfactant Tween 80 (T) are used together in various contexts, including in drug delivery and oil spill remediation. There is hence a need to elucidate the nanostructures in LT mixtures, which is the focus of this paper. We study these mixtures using cryogenic transmission electron microscopy (cryo-TEM), coupled with dynamic light scattering and small-angle neutron scattering. As the concentration of Tween 80 is increased, the vesicles formed by lecithin are transformed into spherical micelles. We identify bicelles (i.e., disc-like micelles) as well as cylindrical micelles as the key stable nanostructures formed at intermediate L/T ratios. The bicelles have diameters ∼13-26 nm, and the bicelle size decreases as the Tween 80 content increases. We propose that the lecithin lipids form the body of the discs, while the Tween 80 surfactants occupy the rims. This hypothesis is consistent with geometric arguments because lecithin is double-tailed and favors minimal curvature, whereas the single-tailed Tween 80 molecules prefer curved interfaces. In the case of cylindrical micelles, cryo-TEM reveals that the micelles are short (length < 22 nm) and flexible. We are able to directly visualize the microstructure of the aggregates formed by lecithin-Tween 80 mixtures, thereby enhancing the understanding of morphological changes in the lecithin-Tween 80 system.
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Affiliation(s)
- Igor Kevin Mkam Tsengam
- Department
of Chemical and Biomolecular Engineering, Tulane University, 300 Lindy Boggs Building, New Orleans, Louisiana 70118, United States
| | - Marzhana Omarova
- Department
of Chemical and Biomolecular Engineering, Tulane University, 300 Lindy Boggs Building, New Orleans, Louisiana 70118, United States
| | - Elizabeth G. Kelley
- Center
for Neutron Research, National Institute
of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Alon McCormick
- Department
of Chemical Engineering and Material Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - Geoffrey D. Bothun
- Department
of Chemical Engineering, University of Rhode
Island, 51 Lower College Road; Kingston, Rhode Island 02881, United States
| | - Srinivasa R. Raghavan
- Department
of Chemical and Biomolecular Engineering, University of Maryland, College
Park, Maryland 20742, United States
| | - Vijay T. John
- Department
of Chemical and Biomolecular Engineering, Tulane University, 300 Lindy Boggs Building, New Orleans, Louisiana 70118, United States
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5
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Ye Z, Wu Z, Jayaraman A. Computational Reverse Engineering Analysis for Scattering Experiments (CREASE) on Vesicles Assembled from Amphiphilic Macromolecular Solutions. JACS AU 2021; 1:1925-1936. [PMID: 34841410 PMCID: PMC8611670 DOI: 10.1021/jacsau.1c00305] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Indexed: 05/25/2023]
Abstract
In this paper we present the development and validation of the "Computational Reverse-Engineering Analysis for Scattering Experiments" (CREASE) method for analyzing scattering results from vesicle structures that are commonly found upon assembly of synthetic, biomimetic, or bioderived amphiphilic copolymers in solution. The two-step CREASE method takes the amphiphilic polymer chemistry and small-angle scattering intensity profile, I exp(q), as input and determines the vesicles' structural features on multiple length scales ranging from assembled vesicle wall's individual layer thicknesses to the monomer-level packing and distribution of polymer conformations. In the first step of CREASE, a genetic algorithm (GA) is used to determine the relevant vesicle dimensions from the input macromolecular solution information and I exp(q) by identifying the structure whose computed scattering profile best matches the input I exp(q). Then in the second step, the GA-determined dimensions are used for molecular reconstruction of the vesicle structure. To validate CREASE for vesicles, we test CREASE on input scattering intensity profiles generated mathematically (termed as in silico I exp(q) vs q) from a variety of vesicle sizes with known dimensions. We also test CREASE on in silico I exp(q) vs q generated from vesicles with dispersity in all relevant dimensions, resembling real experiments. After successful validation of CREASE, we compare the CREASE-determined dimensions against those obtained from the traditional approach of fitting the scattering intensity profile to relevant analytical model in SASVIEW package. We show that CREASE performs better than or as well as the core-multishell analytical model's fitting in SASVIEW in determining vesicle dimensions with dispersity. We also show that CREASE provides structural information beyond those possible from traditional scattering analysis using the core-multishell model, such as the distribution of solvophilic monomers between the vesicle wall's inner and outer layers in the vesicle wall and the chain-level packing within each vesicle layer.
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Affiliation(s)
- Ziyu Ye
- Colburn
Laboratory, Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, Delaware 19716, United States
| | - Zijie Wu
- Colburn
Laboratory, Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, Delaware 19716, United States
| | - Arthi Jayaraman
- Colburn
Laboratory, Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, Delaware 19716, United States
- Department
of Materials Science and Engineering, University
of Delaware, Newark, Delaware 19716, United States
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6
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Chountoulesi M, Perinelli DR, Pippa N, Chrysostomou V, Forys A, Otulakowski L, Bonacucina G, Trzebicka B, Pispas S, Demetzos C. Physicochemical, morphological and thermal evaluation of lyotropic lipidic liquid crystalline nanoparticles: The effect of stimuli-responsive polymeric stabilizer. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.124678] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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7
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Sarmento MJ, Hof M, Šachl R. Interleaflet Coupling of Lipid Nanodomains - Insights From in vitro Systems. Front Cell Dev Biol 2020; 8:284. [PMID: 32411705 PMCID: PMC7198703 DOI: 10.3389/fcell.2020.00284] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 04/02/2020] [Indexed: 01/09/2023] Open
Abstract
The plasma membrane is a complex system, consisting of two layers of lipids and proteins compartmentalized into small structures called nanodomains. Despite the asymmetric composition of both leaflets, coupling between the layers is surprisingly strong. This can be evidenced, for example, by recent experimental studies performed on phospholipid giant unilamellar vesicles showing that nanodomains formed in the outer layer are perfectly registered with those in the inner leaflet. Similarly, microscopic phase separation in one leaflet can induce phase separation in the opposing leaflet that would otherwise be homogeneous. In this review, we summarize the current theoretical and experimental knowledge that led to the current view that domains are – irrespective of their size – commonly registered across the bilayer. Mechanisms inducing registration of nanodomains suggested by theory and calculations are discussed. Furthermore, domain coupling is evidenced by experimental studies based on the sparse number of methods that can resolve registered from independent nanodomains. Finally, implications that those findings using model membrane studies might have for cellular membranes are discussed.
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Affiliation(s)
- Maria J Sarmento
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova, Prague, Czechia
| | - Martin Hof
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova, Prague, Czechia
| | - Radek Šachl
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova, Prague, Czechia
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8
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Leonov DV, Dzuba SA, Surovtsev NV. Normal vibrations of ternary DOPC/DPPC/cholesterol lipid bilayers by low-frequency Raman spectroscopy. RSC Adv 2019; 9:34451-34456. [PMID: 35530012 PMCID: PMC9073921 DOI: 10.1039/c9ra06114b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 10/20/2019] [Indexed: 11/23/2022] Open
Abstract
A lipid bilayer containing a ternary mixture of low- and high-melting lipids and cholesterol (Chol) can give rise to domain formation, referred to as lipid rafts. Low-frequency Raman spectroscopy at reduced temperatures allows detection of normal membrane mechanical vibrations. In this work, Raman spectra were obtained in the spectral range between 5 and 90 cm−1 for bilayers prepared from dioleoyl-glycero-phosphocholine (DOPC), dipalmitoyl-glycero-phosphocholine (DPPC) and Chol. A narrow peak detected between 13 and 16 cm−1 was attributed to the vibrational eigenmode of a lipid monolayer (a leaflet). For the equimolar DOPC/DPPC ratio, the Chol concentration dependence for the peak position, width and amplitude may be divided into three distinct ranges: below 9 mol%, the intermediate range between 9 mol% and 38 mol%, and above 38 mol%. In the intermediate range the peak position attains its minimum, and the peak width drops approximately by a factor of two as compared with the Chol-free bilayers. Meanwhile, this range is known for raft formation in a fluid state. The obtained results may be interpreted as evidence that bilayer structures in the raft-containing fluid state may be frozen at low temperatures. The drop of peak width indicates that at the spatial scale of the experiment (∼2.5 nm) the intermolecular bilayer structure with raft formation becomes more homogeneous and more cohesive. Upon lipid raft formation, the Raman peak corresponding to monolayer normal mechanical vibrations drops remarkably in position and width.![]()
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Affiliation(s)
- Dmitry V. Leonov
- Department of Physics
- Novosibirsk State University
- Novosibirsk
- Russia
| | - Sergei A. Dzuba
- Department of Physics
- Novosibirsk State University
- Novosibirsk
- Russia
- Voevodsky Institute of Chemical Kinetics and Combustion
| | - Nikolay V. Surovtsev
- Department of Physics
- Novosibirsk State University
- Novosibirsk
- Russia
- Institute of Automation and Electrometry
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9
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Alford A, Kozlovskaya V, Kharlampieva E. Small Angle Scattering for Pharmaceutical Applications: From Drugs to Drug Delivery Systems. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1009:239-262. [PMID: 29218564 DOI: 10.1007/978-981-10-6038-0_15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The sub-nanometer scale provided by small angle neutron and X-ray scattering is of special importance to pharmaceutical and biomedical investigators. As drug delivery devices become more functionalized and continue decreasing in size, the ability to elucidate details on size scales smaller than those available from optical techniques becomes extremely pertinent. Information gathered from small angle scattering therefore aids the endeavor of optimizing pharmaceutical efficacy at its most fundamental level. This chapter will provide some relevant examples of drug carrier technology and how small angle scattering (SAS) can be used to solve their mysteries. An emphasis on common first-step data treatments is provided which should help clarify the contents of scattering data to new researchers. Specific examples of pharmaceutically relevant research on novel systems and the role SAS plays in these studies will be discussed. This chapter provides an overview of the current applications of SAS in drug research and some practical considerations for selecting scattering techniques.
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Affiliation(s)
- Aaron Alford
- Department of Chemistry, University of Alabama at Birmingham, 901 14th Street South, CHEM 272, Birmingham, AL, 35294, USA
| | - Veronika Kozlovskaya
- Department of Chemistry, University of Alabama at Birmingham, 901 14th Street South, CHEM 272, Birmingham, AL, 35294, USA
| | - Eugenia Kharlampieva
- Department of Chemistry, University of Alabama at Birmingham, 901 14th Street South, CHEM 272, Birmingham, AL, 35294, USA.
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10
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Heberle FA, Pabst G. Complex biomembrane mimetics on the sub-nanometer scale. Biophys Rev 2017; 9:353-373. [PMID: 28717925 PMCID: PMC5578918 DOI: 10.1007/s12551-017-0275-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 06/26/2017] [Indexed: 12/12/2022] Open
Abstract
Biomimetic lipid vesicles are indispensable tools for gaining insight into the biophysics of cell physiology on the molecular level. The level of complexity of these model systems has steadily increased, and now spans from domain-forming lipid mixtures to asymmetric lipid bilayers. Here, we review recent progress in the development and application of elastic neutron and X-ray scattering techniques for studying these systems in situ and under physiologically relevant conditions on the nanometer to sub-nanometer length scales. In particular, we focus on: (1) structural details of coexisting liquid-ordered and liquid-disordered domains, including their thickness and lipid packing mismatch as a function of a size transition from nanoscopic to macroscopic domains; (2) membrane-mediated protein partitioning into lipid domains; (3) the role of the aqueous medium in tuning interactions between membranes and domains; and (4) leaflet-specific structure in asymmetric bilayers and passive lipid flip-flop.
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Affiliation(s)
- Frederick A Heberle
- The Bredesen Center, University of Tennessee, Knoxville, TN, 37996, USA.,Joint Institute for Biological Sciences and Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Georg Pabst
- Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, University of Graz, 8010, Graz, Austria. .,BioTechMed-Graz, 8010, Graz, Austria.
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11
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Kardash ME, Dzuba SA. Lipid-Mediated Clusters of Guest Molecules in Model Membranes and Their Dissolving in the Presence of Lipid Rafts. J Phys Chem B 2017; 121:5209-5217. [DOI: 10.1021/acs.jpcb.7b01561] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Maria E. Kardash
- Institute of Chemical Kinetics
and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russia
- Department of Physics, Novosibirsk State University, 630090, Novosibirsk, Russia
| | - Sergei A. Dzuba
- Institute of Chemical Kinetics
and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russia
- Department of Physics, Novosibirsk State University, 630090, Novosibirsk, Russia
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12
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Heberle FA, Anghel VN, Katsaras J. Scattering from phase-separated vesicles. I. An analytical form factor for multiple static domains. J Appl Crystallogr 2015. [DOI: 10.1107/s160057671501362x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
This is the first in a series of papers considering elastic scattering from laterally heterogeneous lipid vesicles containing multiple domains. Unique among biophysical tools, small-angle neutron scattering can in principle give detailed information about the size, shape and spatial arrangement of domains. A general theory for scattering from laterally heterogeneous vesicles is presented, and the analytical form factor for static domains with arbitrary spatial configuration is derived, including a simplification for uniformly sized round domains. The validity of the model, including series truncation effects, is assessed by comparison with simulated data obtained from a Monte Carlo method. Several aspects of the analytical solution for scattering intensity are discussed in the context of small-angle neutron scattering data, including the effect of varying domain size and number, as well as solvent contrast. The analysis indicates that effects of domain formation are most pronounced when the vesicle's average scattering length density matches that of the surrounding solvent.
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13
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Bennett SAL, Valenzuela N, Xu H, Franko B, Fai S, Figeys D. Using neurolipidomics to identify phospholipid mediators of synaptic (dys)function in Alzheimer's Disease. Front Physiol 2013; 4:168. [PMID: 23882219 PMCID: PMC3712192 DOI: 10.3389/fphys.2013.00168] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Accepted: 06/18/2013] [Indexed: 11/13/2022] Open
Abstract
Not all of the mysteries of life lie in our genetic code. Some can be found buried in our membranes. These shells of fat, sculpted in the central nervous system into the cellular (and subcellular) boundaries of neurons and glia, are themselves complex systems of information. The diversity of neural phospholipids, coupled with their chameleon-like capacity to transmute into bioactive molecules, provides a vast repertoire of immediate response second messengers. The effects of compositional changes on synaptic function have only begun to be appreciated. Here, we mined 29 neurolipidomic datasets for changes in neuronal membrane phospholipid metabolism in Alzheimer's Disease (AD). Three overarching metabolic disturbances were detected. We found that an increase in the hydrolysis of platelet activating factor precursors and ethanolamine-containing plasmalogens, coupled with a failure to regenerate relatively rare alkyl-acyl and alkenyl-acyl structural phospholipids, correlated with disease severity. Accumulation of specific bioactive metabolites [i.e., PC(O-16:0/2:0) and PE(P-16:0/0:0)] was associated with aggravating tau pathology, enhancing vesicular release, and signaling neuronal loss. Finally, depletion of PI(16:0/20:4), PI(16:0/22:6), and PI(18:0/22:6) was implicated in accelerating Aβ42 biogenesis. Our analysis further suggested that converging disruptions in platelet activating factor, plasmalogen, phosphoinositol, phosphoethanolamine (PE), and docosahexaenoic acid metabolism may contribute mechanistically to catastrophic vesicular depletion, impaired receptor trafficking, and morphological dendritic deformation. Together, this analysis supports an emerging hypothesis that aberrant phospholipid metabolism may be one of multiple critical determinants required for Alzheimer disease conversion.
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Affiliation(s)
- Steffany A L Bennett
- Ottawa Institute of Systems Biology Ottawa, ON, Canada ; Neural Regeneration Laboratory, Department of Biochemistry, Microbiology, and Immunology, University of Ottawa Ottawa, ON, Canada ; CIHR Training Program in Neurodegenerative Lipidomics, Department of Biochemistry, Microbiology, and Immunology, University of Ottawa Ottawa, ON, Canada
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14
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The shape/morphology balance: a study of stealth liposomes via fractal analysis and drug encapsulation. Pharm Res 2013; 30:2385-95. [PMID: 23743657 DOI: 10.1007/s11095-013-1082-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 05/12/2013] [Indexed: 10/26/2022]
Abstract
PURPOSE Fractal analysis was used as a tool in order to study the morphological characteristics of PEGylated liposomes. We report on the morphological characteristics of stealth liposomes composed of DPPC and DPPE-PEG 3000 in two dispersion media using fractal analysis. METHODS Light scattering techniques were used in order to elucidate the size, the morphology and the surface charge of PEGylated liposomes as a function of PEGylated lipid concentration and temperature. Fluorescence spectroscopy studies revealed a microenvironment of low polarity inside the liposomal membranes. RESULTS All formulations were found to retain their physicochemical characteristics for at least 3 weeks. The hydrodynamic radii (Rh) of stealth liposomes were stable in the process of heating up to 50°C; while the fractal dimension values (df) which correspond to their morphology, have been changed during heating. Hence, these results are a first indication of the presence of a heterogeneous microdomain structure of the stealth liposomal system. The amphiphilic drug indomethacin (IND) was successfully encapsulated within the liposomes and led to an increased size of stealth liposomes, while the morphology of liposomal vectors changed significantly at the highest molar ratio of PEGylated lipid. CONCLUSIONS We can state that this approach can promote a new analytical concept based on the morphological characteristics and quantify the shape of drug carriers complementary to that of the conventional analytical techniques.
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15
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Pan J, Heberle FA, Petruzielo RS, Katsaras J. Using small-angle neutron scattering to detect nanoscopic lipid domains. Chem Phys Lipids 2013; 170-171:19-32. [PMID: 23518250 DOI: 10.1016/j.chemphyslip.2013.02.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 02/27/2013] [Accepted: 02/28/2013] [Indexed: 11/25/2022]
Abstract
The cell plasma membrane is a complex system, which is thought to be capable of exhibiting non-random lateral organization. Studies of live cells and model membranes have yielded mechanisms responsible for the formation, growth, and maintenance of nanoscopic heterogeneities, although the existence and mechanisms that give rise to these heterogeneities remain controversial. Small-angle neutron scattering (SANS) is a tool ideally suited to interrogate lateral heterogeneity in model membranes, primarily due to its unique spatial resolution (i.e., ~5-100nm) and its ability to resolve structure with minimal perturbation to the membrane. In this review we examine several methods used to analyze the SANS signal arising from freely suspended unilamellar vesicles containing lateral heterogeneity. Specifically, we discuss an analytical model for a single, round domain on a spherical vesicle. We then discuss a numerical method that uses Monte Carlo simulation to describe systems with multiple domains and/or more complicated morphologies. Also discussed are several model-independent approaches that are sensitive to membrane heterogeneity. The review concludes with several recent applications of SANS to the study of membrane raft mixtures.
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Affiliation(s)
- Jianjun Pan
- Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States.
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16
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Hadjidemetriou M, Pippa N, Pispas S, Demetzos C. Incorporation of dimethoxycurcumin into charged liposomes and the formation kinetics of fractal aggregates of uncharged vectors. J Liposome Res 2013; 23:94-100. [DOI: 10.3109/08982104.2012.747534] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Pippa N, Pispas S, Demetzos C. The delineation of the morphology of charged liposomal vectors via a fractal analysis in aqueous and biological media: physicochemical and self-assembly studies. Int J Pharm 2012; 437:264-74. [PMID: 22939965 DOI: 10.1016/j.ijpharm.2012.08.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 07/24/2012] [Accepted: 08/09/2012] [Indexed: 01/09/2023]
Abstract
The present study deals with the physicochemical characterization of DPPC:DPPG (9:1 molar ratio) and DPPC:DODAP (9:1 molar ratio) liposomes, and the determination of their fractal dimension in HPLC-grade water, PBS and in FBS. Light scattering techniques were used in order to extract information on the structure, morphology, size and surface charge of liposomes in an ageing study and their structural response to changes in concentration and temperature. Fluorescence spectroscopy showed that the microviscosity of cationic liposomes changed by an increase of temperature. The fractal dimension, d(f), was found equal to 1.8 for reconstituted DPPC:DPPG (9:1) and DPPC:DODAP (9:1) liposomes in aqueous media. Aggregation of reconstituted DPPC:DPPG (9:1) and DPPC:DODAP (9:1) liposomes in FBS was observed. Their fractal dimensions were 1.46 and 2.45, respectively. The first order aggregation kinetics of DPPC:DODAP (9:1) liposomes in the presence of serum proteins was determined; the aggregates of cationic liposomes with serum components remained stable during 20 days with fractal dimension 2.5. The responsiveness of cationic liposomes to changes in temperature in the three dispersion media has revealed the self-assembly and the morphological complexity of cationic vectors. Finally, we suggest that these studies could be used for developing effective advanced drug delivery nano-systems (aDDnSs) based on their fractal characteristics which effectively draw their morphological profile.
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Affiliation(s)
- Natassa Pippa
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Athens, Panepistimioupolis Zografou, 15771 Athens, Greece
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Filippov SK, Chytil P, Konarev PV, Dyakonova M, Papadakis C, Zhigunov A, Plestil J, Stepanek P, Etrych T, Ulbrich K, Svergun DI. Macromolecular HPMA-Based Nanoparticles with Cholesterol for Solid-Tumor Targeting: Detailed Study of the Inner Structure of a Highly Efficient Drug Delivery System. Biomacromolecules 2012; 13:2594-604. [DOI: 10.1021/bm3008555] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Sergey K. Filippov
- Institute of Macromolecular
Chemistry, Academy of Sciences of the Czech Republic, v. v. i., Heyrovský Sq. 2, 162 06 Prague
6, Czech Republic
| | - Petr Chytil
- Institute of Macromolecular
Chemistry, Academy of Sciences of the Czech Republic, v. v. i., Heyrovský Sq. 2, 162 06 Prague
6, Czech Republic
| | - Petr V. Konarev
- European Molecular
Biology Laboratory, EMBL c/o DESY, Notkestrasse 85, D-22603 Hamburg, Germany
| | - Margarita Dyakonova
- Physik-Department, Technische Universität München, Physik-Department,
Fachgebiet
Physik weicher Materie, James-Franck-Str. 1, 85747 Garching, Germany
| | - ChristineM. Papadakis
- Physik-Department, Technische Universität München, Physik-Department,
Fachgebiet
Physik weicher Materie, James-Franck-Str. 1, 85747 Garching, Germany
| | - Alexander Zhigunov
- Institute of Macromolecular
Chemistry, Academy of Sciences of the Czech Republic, v. v. i., Heyrovský Sq. 2, 162 06 Prague
6, Czech Republic
| | - Josef Plestil
- Institute of Macromolecular
Chemistry, Academy of Sciences of the Czech Republic, v. v. i., Heyrovský Sq. 2, 162 06 Prague
6, Czech Republic
| | - Petr Stepanek
- Institute of Macromolecular
Chemistry, Academy of Sciences of the Czech Republic, v. v. i., Heyrovský Sq. 2, 162 06 Prague
6, Czech Republic
| | - Tomas Etrych
- Institute of Macromolecular
Chemistry, Academy of Sciences of the Czech Republic, v. v. i., Heyrovský Sq. 2, 162 06 Prague
6, Czech Republic
| | - Karel Ulbrich
- Institute of Macromolecular
Chemistry, Academy of Sciences of the Czech Republic, v. v. i., Heyrovský Sq. 2, 162 06 Prague
6, Czech Republic
| | - Dmitri I. Svergun
- European Molecular
Biology Laboratory, EMBL c/o DESY, Notkestrasse 85, D-22603 Hamburg, Germany
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The fractal hologram and elucidation of the structure of liposomal carriers in aqueous and biological media. Int J Pharm 2012; 430:65-73. [DOI: 10.1016/j.ijpharm.2012.03.048] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 03/23/2012] [Indexed: 12/13/2022]
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Ghosh SK, Aeffner S, Salditt T. Effect of PIP2 on Bilayer Structure and Phase Behavior of DOPC: An X-ray Scattering Study. Chemphyschem 2011; 12:2633-40. [DOI: 10.1002/cphc.201100154] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Revised: 06/16/2011] [Indexed: 01/16/2023]
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Knaapila M, Bright DW, Nehls BS, Garamus VM, Almásy L, Schweins R, Scherf U, Monkman AP. Development of Intermolecular Structure and Beta-phase of Random Poly[9,9-bis(2-ethylhexyl)fluorene]-co-(9,9-dioctylfluorene) in Methylcyclohexane. Macromolecules 2011. [DOI: 10.1021/ma201250h] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Matti Knaapila
- Physics Department, Institute for Energy Technology, NO-2027 Kjeller, Norway
| | - Daniel W. Bright
- Department of Physics, University of Durham, DH1 3LE Durham, England
| | | | - Vasil M. Garamus
- Helmholtz-Zentrum Geesthacht, Zentrum für Material- und Küstenforschung GmbH, DE-21502 Geesthacht, Germany
| | - László Almásy
- Research Institute for Solid State Physics and Optics, Budapest-1525, Hungary
| | - Ralf Schweins
- Institut Laue-Langevin, DS/LSS Group, 38042 Grenoble Cedex 9, France
| | - Ullrich Scherf
- Fachbereich Chemie, Bergische Universität Wuppertal, DE-42097 Wuppertal, Germany
| | - Andrew P. Monkman
- Department of Physics, University of Durham, DH1 3LE Durham, England
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