1
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Apoptosis Detection in Retinal Ganglion Cells Using Quantitative Changes in Multichannel Fluorescence Colocalization. BIOSENSORS 2022; 12:bios12090693. [PMID: 36140078 PMCID: PMC9496076 DOI: 10.3390/bios12090693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/05/2022] [Accepted: 08/18/2022] [Indexed: 11/17/2022]
Abstract
KcapTR488 is a dual-fluorophore peptide sensor for the real-time reporting of programmed cell death by fluorescence imaging. KcapTR488 contains a nuclear localization sequence (NLS) conjugated with Texas Red, a caspase-cleavable sequence (DEVD), and a C-terminus conjugated to Alexa Fluor 488 (AF488). The synthesis and preliminary evaluation in cellulo of KcapTR488 for monitoring cell death by fluorescence imaging has been previously reported, but its utility in vivo has yet to be tested or validated. Herein, in vitro solution experiments verified the intramolecular fluorescence resonance energy transfer (FRET) between the two fluorophores and enabled a quantitative analysis of enzyme rates and selectivity. The sensor delivery kinetics in live rat models were quantified by ex vivo fluorescence microscopy. Studies in healthy control retinas demonstrated that KcapTR488 concentrated in the nucleus of retinal ganglion cells (RGC), with a strong colocalization of red and green fluorescence signals producing robust FRET signals, indicating an intact reporter. By contrast, using an acute but mild NMDA-induced retinal injury model, dual-color confocal ex vivo microscopy of cleaved KcapTR488 identified sensor activation as early as 2 h after injection. Quantitative changes in fluorescence colocalization were superior to changes in FRET for monitoring injury progression. Longitudinal monitoring revealed that the NLS-Texas Red fragment of the cleaved sensor moved out of the cell body, down the axon, and exited the retina, consistent with anterograde axonal transport. Thus, KcapTR488 may be a powerful tool to study RGC death pathways in live preclinical models of glaucoma.
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2
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Hitaishi P, Mandal P, Ghosh SK. Partitioning of a Hybrid Lipid in Domains of Saturated and Unsaturated Lipids in a Model Cellular Membrane. ACS OMEGA 2021; 6:34546-34554. [PMID: 34963939 PMCID: PMC8697375 DOI: 10.1021/acsomega.1c04835] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/30/2021] [Indexed: 06/14/2023]
Abstract
The cellular membranes are composed of hundreds of components such as lipids, proteins, and sterols that are chemically and physically distinct from each other. The lipid-lipid and lipid-protein interactions form domains in this membrane, which play vital roles in membrane physiology. The hybrid lipids (HLs) with one saturated and one unsaturated chain can control the shape and size of these domains, ensuring the thermodynamic stability of a membrane. In this study, the thermodynamics of mixing of a HL and its structural effects on the phase separated domains in a model membrane composed of a saturated and an unsaturated lipid have been investigated. The HL is observed to mix into an unsaturated lipid reducing the Gibbs free energy, whereas the mixing is unfavorable in a saturated lipid. The presence of an HL in an unsaturated lipid tends to increase its area fraction, which is reflected in the enhanced correlation length across the bilayers in a multilayered sample. There is a feeble effect on the domain structure of the saturated lipid due to the presence of the HLs at the phase boundary. This study concludes that the HLs preferentially participate in the unsaturated lipid regions compared to that of a saturated lipid.
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3
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Gunther G, Malacrida L, Jameson DM, Gratton E, Sánchez SA. LAURDAN since Weber: The Quest for Visualizing Membrane Heterogeneity. Acc Chem Res 2021; 54:976-987. [PMID: 33513300 PMCID: PMC8552415 DOI: 10.1021/acs.accounts.0c00687] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Any chemist studying the interaction of molecules with lipid assemblies will eventually be confronted by the topic of membrane bilayer heterogeneity and may ultimately encounter the heterogeneity of natural membranes. In artificial bilayers, heterogeneity is defined by phase segregation that can be in the nano- and micrometer range. In biological bilayers, heterogeneity is considered in the context of small (10-200 nm) sterol and sphingolipid-enriched heterogeneous and highly dynamic domains. Several techniques can be used to assess membrane heterogeneity in living systems. Our approach is to use a fluorescent reporter molecule immersed in the bilayer, which, by changes in its spectroscopic properties, senses physical-chemistry aspects of the membrane. This dye in combination with microscopy and fluctuation techniques can give information about membrane heterogeneity at different temporal and spatial levels: going from average fluidity to number and diffusion coefficient of nanodomains. LAURDAN (6-dodecanoyl-2-(dimethylamino) naphthalene), is a fluorescent probe designed and synthesized in 1979 by Gregorio Weber with the purpose to study the phenomenon of dipolar relaxation. The spectral displacement observed when LAURDAN is either in fluid or gel phase permitted the use of the technique in the field of membrane dynamics. The quantitation of the spectral displacement was first addressed by the generalized polarization (GP) function in the cuvette, a ratio of the difference in intensity at two wavelengths divided by their sum. In 1997, GP measurements were done for the first time in the microscope, adding to the technique the spatial resolution and allowing the visualization of lipid segregation both in liposomes and cells. A new prospective to the membrane heterogeneity was obtained when LAURDAN fluorescent lifetime measurements were done in the microscope. Two channel lifetime imaging provides information on membrane polarity and dipole relaxation (the two parameters responsible for the spectral shift of LAURDAN), and the application of phasor analysis allows pixel by pixel understanding of these two parameters in the membrane. To increase temporal resolution, LAURDAN GP was combined with fluctuation correlation spectroscopy (FCS) and the motility of nanometric highly packed structures in biological membranes was registered. Lately the application of phasor analysis to spectral images from membranes labeled with LAURDAN allows us to study the full spectra pixel by pixel in an image. All these methodologies, using LAURDAN, offer the possibility to address different properties of membranes depending on the question being asked. In this Account, we will focus on the principles, advantages, and limitations of different approaches to orient the reader to select the most appropriate technique for their research.
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Affiliation(s)
- German Gunther
- Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Sergio Livingstone P. 1007, Santiago 8380492, Chile
| | - Leonel Malacrida
- Advanced Microscopy and Biophotonics Unit, Hospital de Clínicas, Universidad de la República, Montevideo-Uruguay. Advanced Bioimaging Unit, Institut Pasteur Montevideo, Av. Italia s/n, 90600 Montevideo, Uruguay
| | - David M Jameson
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo Street, Biosciences 222, Honolulu, Hawaii 96813, United States
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, 3210 Natural Sciences II, University of California, Irvine, Irvine, California 92697-2725, United States
| | - Susana A Sánchez
- Departamento de Polímeros, Facultad de Ciencias Químicas, Universidad de Concepción, Edmundo Larenas 129, Concepción 4070371, Chile
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Khmelinskaia A, Marquês JMT, Bastos AEP, Antunes CAC, Bento-Oliveira A, Scolari S, Lobo GMDS, Malhó R, Herrmann A, Marinho HS, de Almeida RFM. Liquid-Ordered Phase Formation by Mammalian and Yeast Sterols: A Common Feature With Organizational Differences. Front Cell Dev Biol 2020; 8:337. [PMID: 32596234 PMCID: PMC7304482 DOI: 10.3389/fcell.2020.00337] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/17/2020] [Indexed: 11/13/2022] Open
Abstract
Here, biophysical properties of membranes enriched in three metabolically related sterols are analyzed both in vitro and in vivo. Unlike cholesterol and ergosterol, the common metabolic precursor zymosterol is unable to induce the formation of a liquid ordered (l o) phase in model lipid membranes and can easily accommodate in a gel phase. As a result, Zym has a marginal ability to modulate the passive membrane permeability of lipid vesicles with different compositions, contrary to cholesterol and ergosterol. Using fluorescence-lifetime imaging microscopy of an aminostyryl dye in living mammalian and yeast cells we established a close parallel between sterol-dependent membrane biophysical properties in vivo and in vitro. This approach unraveled fundamental differences in yeast and mammalian plasma membrane organization. It is often suggested that, in eukaryotes, areas that are sterol-enriched are also rich in sphingolipids, constituting highly ordered membrane regions. Our results support that while cholesterol is able to interact with saturated lipids, ergosterol seems to interact preferentially with monounsaturated phosphatidylcholines. Taken together, we show that different eukaryotic kingdoms developed unique solutions for the formation of a sterol-rich plasma membrane, a common evolutionary trait that accounts for sterol structural diversity.
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Affiliation(s)
- Alena Khmelinskaia
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Joaquim M T Marquês
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - André E P Bastos
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Catarina A C Antunes
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Andreia Bento-Oliveira
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Silvia Scolari
- Department of Biology, Molecular Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Gerson M da S Lobo
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Rui Malhó
- Faculdade de Ciências, BioISI, Universidade de Lisboa, Lisbon, Portugal
| | - Andreas Herrmann
- Department of Biology, Molecular Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | - H Susana Marinho
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Rodrigo F M de Almeida
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
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5
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Calori IR, Pazin WM, Brunaldi K, Pellosi DS, Caetano W, Tedesco AC, Hioka N. Laurdan as fluorescent probe to determinate the critical micelle temperature of polymers from Pluronic®-coated fluid phase liposomes. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111562] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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6
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Steinkühler J, Sezgin E, Urbančič I, Eggeling C, Dimova R. Mechanical properties of plasma membrane vesicles correlate with lipid order, viscosity and cell density. Commun Biol 2019; 2:337. [PMID: 31531398 PMCID: PMC6744421 DOI: 10.1038/s42003-019-0583-3] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 08/15/2019] [Indexed: 11/08/2022] Open
Abstract
Regulation of plasma membrane curvature and composition governs essential cellular processes. The material property of bending rigidity describes the energetic cost of membrane deformations and depends on the plasma membrane molecular composition. Because of compositional fluctuations and active processes, it is challenging to measure it in intact cells. Here, we study the plasma membrane using giant plasma membrane vesicles (GPMVs), which largely preserve the plasma membrane lipidome and proteome. We show that the bending rigidity of plasma membranes under varied conditions is correlated to readout from environment-sensitive dyes, which are indicative of membrane order and microviscosity. This correlation holds across different cell lines, upon cholesterol depletion or enrichment of the plasma membrane, and variations in cell density. Thus, polarity- and viscosity-sensitive probes represent a promising indicator of membrane mechanical properties. Additionally, our results allow for identifying synthetic membranes with a few well defined lipids as optimal plasma membrane mimetics.
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Affiliation(s)
- Jan Steinkühler
- Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
| | - Erdinc Sezgin
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford, OX3 9DS UK
| | - Iztok Urbančič
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford, OX3 9DS UK
- Condensed Matter Physics Department, “Jožef Stefan” Institute, Ljubljana, Slovenia
| | - Christian Eggeling
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford, OX3 9DS UK
- Institute of Applied Optics Friedrich‐Schiller‐University Jena, Max-Wien Platz 4, 07743 Jena, Germany
- Leibniz Institute of Photonic Technology e.V., Albert-Einstein-Straße 9, 07745 Jena, Germany
| | - Rumiana Dimova
- Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
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7
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Watanabe N, Suga K, Slotte JP, Nyholm TKM, Umakoshi H. Lipid-Surrounding Water Molecules Probed by Time-Resolved Emission Spectra of Laurdan. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:6762-6770. [PMID: 31021095 DOI: 10.1021/acs.langmuir.9b00303] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The hydration states of the interfacial region of lipid bilayers were investigated on the basis of the time-resolved emission spectra (TRES) analysis of 6-lauroyl-2-dimethylamino naphthalene (Laurdan), a common fluorescence probe used to analyze membrane hydration. TRES derived from long and short lifetime components were extracted from samples of different lipid species: 1,2-dipalmitoyl- sn-glycero-3-phosphocholine (DPPC), 1,2-dioleoyl- sn-glycero-3-phosphocholine (DOPC), d- erythro- N-palmitoyl-sphingosylphosphorylcholine (PSM), and a DOPC/PSM binary bilayer system. Neither lifetime component (short or long) corresponded with the hydration properties; the short lifetime component of DOPC (1.97 ns) exhibited a peak at 440 nm, and the long lifetime components of DPPC and PSM (7.76 and 7.77 ns, respectively) exhibited peaks at the same wavelength. This similarity arose from the competition between the collisional quenching and the hydration effects of water molecules. Herein, this phenomenon was investigated using a plot of the lifetime τ and the peak position λ (τ vs λ plot), simultaneously visualizing both effects by deconvoluting the TRES. On the basis of collisional quenching theory, the distribution of the water population per lipid (water map) was generated. According to this theory, the τ vs λ plot was applied to the water map and the calculation of the number of water molecules per lipid, which is consistent with previous reports. This approach provides novel insights for the analysis of molecular hydration states using the fluorescence of Laurdan.
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Affiliation(s)
- Nozomi Watanabe
- Division of Chemical Engineering, Graduate School of Engineering Science , Osaka University , 1-3 Machikaneyama-cho , Toyonaka , Osaka 560-8531 , Japan
| | - Keishi Suga
- Division of Chemical Engineering, Graduate School of Engineering Science , Osaka University , 1-3 Machikaneyama-cho , Toyonaka , Osaka 560-8531 , Japan
| | - J Peter Slotte
- Biochemistry, Faculty of Science and Engineering , Åbo Akademi University , Tykistökatu 6A , Turku FI-20520 , Finland
| | - Thomas K M Nyholm
- Biochemistry, Faculty of Science and Engineering , Åbo Akademi University , Tykistökatu 6A , Turku FI-20520 , Finland
| | - Hiroshi Umakoshi
- Division of Chemical Engineering, Graduate School of Engineering Science , Osaka University , 1-3 Machikaneyama-cho , Toyonaka , Osaka 560-8531 , Japan
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8
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Begarani F, D'Autilia F, Signore G, Del Grosso A, Cecchini M, Gratton E, Beltram F, Cardarelli F. Capturing Metabolism-Dependent Solvent Dynamics in the Lumen of a Trafficking Lysosome. ACS NANO 2019; 13:1670-1682. [PMID: 30649861 DOI: 10.1021/acsnano.8b07682] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The eukaryotic cell compartmentalizes into spatially confined, membrane-enclosed, intracellular structures ( e. g., organelles, endosomes, and vesicles). Here, peculiar physicochemical properties of the local environment occur and participate in the regulation of ongoing molecular processes. In spite of the huge amount of available environmental probes, experiments on subcellular structures are severely challenged by their three-dimensional (3D) movement. This bottleneck is tackled here by focusing an excitation light beam in a periodic orbit around the structure of interest. The recorded signal is used as feedback to localize the structure position at high temporal resolution: microseconds along the orbit, milliseconds between orbits. The lysosome is selected as the intracellular target, together with 6-acetyl-2-dimethylaminonaphthalene (ACDAN) as probe of the physicochemical properties of the intralysosomal environment. Generalized polarization (GP) analysis of ACDAN emission is used to get a quantitative view on intralysosomal solvent dipolar relaxation. Thus, raster image correlation spectroscopy (RICS) analysis reveals that the ACDAN GP signal is fluctuating in the micro-to-millisecond time range during natural organelle 3D trafficking. We show that ACDAN GP fluctuations are characteristic of lysosomes in living cells, are selectively abolished by lysosomal basification, and depend on metabolic energy in the form of ATP. We argue that intralysosomal ACDAN GP fluctuates according to the ongoing organelle metabolism. Indeed, we report alterations in amplitude and timing of GP fluctuations in a cellular model of lysosomal storage disorder (LSD). The strategy proposed provides insight into the elusive local environment of a trafficking lysosome and supports similar molecular investigations at the subcellular level.
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Affiliation(s)
- Filippo Begarani
- Laboratorio NEST, Scuola Normale Superiore , Pisa 56127 , Italy
- Center for Nanotechnology Innovation@NEST (CNI@NEST) , Pisa 56127 , Italy
| | | | | | - Ambra Del Grosso
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore , Pisa 56127 , Italy
| | - Marco Cecchini
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore , Pisa 56127 , Italy
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering , University of California , Irvine , California 92697-2715 , United States
| | - Fabio Beltram
- Laboratorio NEST, Scuola Normale Superiore , Pisa 56127 , Italy
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9
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Visualizing the regulation of SLC34 proteins at the apical membrane. Pflugers Arch 2019; 471:533-542. [PMID: 30613865 DOI: 10.1007/s00424-018-02249-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 12/19/2018] [Accepted: 12/20/2018] [Indexed: 10/27/2022]
Abstract
The cloning of the renal NaPi-2a (SLC34A1) and NaPi-2c (SLC34A3) phosphate transporters has made it possible to characterize the molecular and biophysical regulation of renal proximal tubular reabsorption of inorganic phosphate (Pi). Dietary factors, such as Pi and K, and several hormones and phosphatonins, including parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23), and glucocorticoids, regulate the transporters through various transcriptional, translational, and post-translational mechanisms that involve acute trafficking via endocytosis or exocytosis, interactions with PDZ domain proteins, lipid microdomains, and diffusion and clustering in the apical brush border membrane. The visualization of these trafficking events by means of novel microscopy techniques that includes fluorescence lifetime imaging microscopy (FLIM), Förster resonance energy transfer (FRET), fluctuation correlation spectroscopy (FCS), and modulation tracking (MT), is the primary focus of this review.
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10
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Gunther G, Jameson DM, Aguilar J, Sánchez SA. Scanning fluorescence correlation spectroscopy comes full circle. Methods 2018; 140-141:52-61. [DOI: 10.1016/j.ymeth.2018.01.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 01/23/2018] [Accepted: 01/30/2018] [Indexed: 11/26/2022] Open
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11
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LPS-Induced Macrophage Activation and Plasma Membrane Fluidity Changes are Inhibited Under Oxidative Stress. J Membr Biol 2016; 249:789-800. [PMID: 27619206 DOI: 10.1007/s00232-016-9927-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 08/30/2016] [Indexed: 10/21/2022]
Abstract
Macrophage activation is essential for a correct and efficient response of innate immunity. During oxidative stress membrane receptors and/or membrane lipid dynamics can be altered, leading to dysfunctional cell responses. Our aim is to analyze membrane fluidity modifications and cell function under oxidative stress in LPS-activated macrophages. Membrane fluidity of individual living THP-1 macrophages was evaluated by the technique two-photon microscopy. LPS-activated macrophage function was determined by TNFα secretion. It was shown that LPS activation causes fluidification of macrophage plasma membrane and production of TNFα. However, oxidative stress induces rigidification of macrophage plasma membrane and inhibition of cell activation, which is evidenced by a decrease of TNFα secretion. Thus, under oxidative conditions macrophage proinflammatory response might develop in an inefficient manner.
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12
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Rascol E, Devoisselle JM, Chopineau J. The relevance of membrane models to understand nanoparticles-cell membrane interactions. NANOSCALE 2016; 8:4780-98. [PMID: 26868717 DOI: 10.1039/c5nr07954c] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Over the past two decades, numerous types of nanoparticles (NPs) have been developed for medical applications; however only a few nanomedicines are actually available on the market. One reason is the lack of understanding and data concerning the NP fate and their behavior upon contact with biological media and cell membranes. Biomimetic membrane models are interesting tools to approach and understand NPs-cell membrane interactions. The use of these models permits one to control physical and chemical parameters and to rapidly compare membrane types and the influence of different media conditions. The interactions between NPs and cell membranes can be qualified and quantified using analytical and modeling methods. In this review, the major studies concerning NPs-cell membrane models and associated methods are described. The advantages and drawbacks for each method are compared for the different models. The key mechanisms of interactions between NPs and cell membranes are revealed using cell membrane models and are interrogated in comparison with the NP behavior in cellulo or in vivo. Investigating the interactions between NPs and cell membrane models is now proposed as an intermediate step between physicochemical characterization of NPs and biological assays.
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Affiliation(s)
- Estelle Rascol
- Institut Charles Gerhardt, UMR 5253 CNRS/ENSCM/UM, 8 rue de l'Ecole Normale, 34296, Cedex 5 Montpellier, France
| | - Jean-Marie Devoisselle
- Institut Charles Gerhardt, UMR 5253 CNRS/ENSCM/UM, 8 rue de l'Ecole Normale, 34296, Cedex 5 Montpellier, France
| | - Joël Chopineau
- Institut Charles Gerhardt, UMR 5253 CNRS/ENSCM/UM, 8 rue de l'Ecole Normale, 34296, Cedex 5 Montpellier, France and Université de Nimes Rue Georges Salan, 30000 Nimes, France.
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13
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Bagatolli LA. Monitoring Membrane Hydration with 2-(Dimethylamino)-6-Acylnaphtalenes Fluorescent Probes. Subcell Biochem 2015; 71:105-125. [PMID: 26438263 DOI: 10.1007/978-3-319-19060-0_5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A family of polarity sensitive fluorescent probes (2-(dimethylamino)-6-acylnaphtalenes, i.e. LAURDAN, PRODAN, ACDAN) was introduced by Gregorio Weber in 1979, with the aim to monitor solvent relaxation phenomena on protein matrices. In the following years, however, PRODAN and particularly LAURDAN, were used to study membrane lateral structure and associated dynamics. Once incorporated into membranes, the (nanosecond) fluorescent decay of these probes is strongly affected by changes in the local polarity and relaxation dynamics of restricted water molecules existing at the membrane/water interface. For instance, when glycerophospholipid containing membranes undertake a solid ordered (gel) to liquid disordered phase transition the fluorescence emission maximum of these probes shift ~ 50 nm with a significant change in their fluorescence lifetime. Furthermore, the fluorescence parameters of LAURDAN and PRODAN are exquisitely sensitive to cholesterol effects, allowing interpretations that correlate changes in membrane packing with membrane hydration. Different membrane model systems as well as innate biological membranes have been studied with this family of probes allowing interesting comparative studies. This chapter presents a short historical overview about these fluorescent reporters, discusses on different models proposed to explain their sensitivity to membrane hydration, and includes relevant examples from experiments performed in artificial and biological membranes.
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Affiliation(s)
- Luis A Bagatolli
- Membrane Biophysics and Biophotonics Group/MEMPHYS-Center for Biomembrane Physics, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark.
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14
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van Maarschalkerweerd A, Vetri V, Langkilde AE, Foderà V, Vestergaard B. Protein/lipid coaggregates are formed during α-synuclein-induced disruption of lipid bilayers. Biomacromolecules 2014; 15:3643-54. [PMID: 25210839 DOI: 10.1021/bm500937p] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Amyloid formation is associated with neurodegenerative diseases such as Parkinson's disease (PD). Significant α-synuclein (αSN) deposition in lipid-rich Lewy bodies is a hallmark of PD. Nonetheless, an unraveling of the connection between neurodegeneration and amyloid fibrils, including the molecular mechanisms behind potential amyloid-mediated toxic effects, is still missing. Interaction between amyloid aggregates and the lipid cell membrane is expected to play a key role in the disease progress. Here, we present experimental data based on hybrid analysis of two-photon-microscopy, solution small-angle X-ray scattering and circular dichroism data. Data show in real time changes in liposome morphology and stability upon protein addition and reveal that membrane disruption mediated by amyloidogenic αSN is associated with dehydration of anionic lipid membranes and stimulation of protein secondary structure. As a result of membrane fragmentation, soluble αSN:-lipid coaggregates are formed, hence, suggesting a novel molecular mechanism behind PD amyloid cytotoxicity.
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Affiliation(s)
- Andreas van Maarschalkerweerd
- Department of Drug Design and Pharmacology, University of Copenhagen , Universitetsparken 2, 2100 Copenhagen, Denmark
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15
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Quercetin and epigallocatechin-3-gallate effect on the anisotropy of model membranes with cholesterol. Food Chem Toxicol 2013; 61:94-100. [DOI: 10.1016/j.fct.2013.03.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Revised: 03/06/2013] [Accepted: 03/10/2013] [Indexed: 01/09/2023]
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16
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Laurdan generalized polarization fluctuations measures membrane packing micro-heterogeneity in vivo. Proc Natl Acad Sci U S A 2012; 109:7314-9. [PMID: 22529342 DOI: 10.1073/pnas.1118288109] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Cellular membranes are heterogeneous in composition, and the prevailing theory holds that the structures responsible for this heterogeneity in vivo are small structures (10-200 nm), sterol- and sphingolipid-enriched, of different sizes, highly dynamic denominated rafts. Rafts are postulated to be platforms, which by sequestering different membrane components can compartmentalize cellular processes and regulate signaling pathways. Despite an enormous effort in this area, the existence of these domains is still under debate due to the characteristics of the structures itself: small in size and highly mobile, which from the technical point of view implies using techniques with high spatial and temporal resolution. In this report we measured rapid fluctuations of the normalized ratio of the emission intensity at two wavelengths of Laurdan, a membrane fluorescent dye sensitive to local membrane packing. We observed generalized polarization fluctuations in the plasma membrane of intact rabbit erythrocytes and Chinese hamster ovary cells that can be explained by the existence of tightly packed micro-domains moving in a more fluid background phase. These structures, which display different lipid packing, have different sizes; they are found in the same cell and in the entire cell population. The small size and characteristic high lipid packing indicate that these micro-domains have properties that have been proposed for lipid rafts.
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Bagatolli LA. LAURDAN Fluorescence Properties in Membranes: A Journey from the Fluorometer to the Microscope. SPRINGER SERIES ON FLUORESCENCE 2012. [DOI: 10.1007/4243_2012_42] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Sarkar P, Luchowski R, Raut S, Sabnis N, Remaley A, Lacko AG, Thamake S, Gryczynski Z, Gryczynski I. Studies on solvatochromic properties of aminophenylstyryl-quinolinum dye, LDS 798, and its application in studying submicron lipid based structure. Biophys Chem 2010; 153:61-9. [DOI: 10.1016/j.bpc.2010.10.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Accepted: 10/04/2010] [Indexed: 10/19/2022]
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