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Lebreton S, Paladino S, Lelek M, Tramier M, Zimmer C, Zurzolo C. Actin cytoskeleton differently regulates cell surface organization of GPI-anchored proteins in polarized epithelial cells and fibroblasts. Front Mol Biosci 2024; 11:1360142. [PMID: 38774234 PMCID: PMC11106487 DOI: 10.3389/fmolb.2024.1360142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 04/11/2024] [Indexed: 05/24/2024] Open
Abstract
The spatiotemporal compartmentalization of membrane-associated glycosylphosphatidylinositol-anchored proteins (GPI-APs) on the cell surface regulates their biological activities. These GPI-APs occupy distinct cellular functions such as enzymes, receptors, and adhesion molecules, and they are implicated in several vital cellular processes. Thus, unraveling the mechanisms and regulators of their membrane organization is essential. In polarized epithelial cells, GPI-APs are enriched at the apical surface, where they form small cholesterol-independent homoclusters and larger heteroclusters accommodating multiple GPI-AP species, all confined within areas of approximately 65-70 nm in diameter. Notably, GPI-AP homoclustering occurs in the Golgi apparatus through a cholesterol- and calcium-dependent mechanism that drives their apical sorting. Despite the critical role of Golgi GPI-AP clustering in their cell surface organization and the importance of cholesterol in heterocluster formation, the regulatory mechanisms governing GPI-AP surface organization, particularly in the context of epithelial polarity, remain elusive. Given that the actin cytoskeleton undergoes substantial remodeling during polarity establishment, this study explores whether the actin cytoskeleton regulates the spatiotemporal apical organization of GPI-APs in MDCK cells. Utilizing various imaging techniques (number and brightness, FRET/FLIM, and dSTORM coupled to pair correlation analysis), we demonstrate that the apical organization of GPI-APs, at different scales, does not rely on the actin cytoskeleton, unlike in fibroblastic cells. Interestingly, calcium chelation disrupts the organization of GPI-APs at the apical surface by impairing Golgi GPI-AP clustering, emphasizing the existence of an interplay among Golgi clustering, apical sorting, and surface organization in epithelial cells. In summary, our findings unveil distinct mechanisms regulating the organization of GPI-APs in cell types of different origins, plausibly allowing them to adapt to different external signals and different cellular environments in order to achieve specialized functions.
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Affiliation(s)
- Stéphanie Lebreton
- Institut Pasteur, Unité de Trafic Membranaire et Pathogenèse, Paris, France
| | - Simona Paladino
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Mickaël Lelek
- Imaging and Modeling Unit, Department of Computational Biology, Institut Pasteur, Paris, France
| | - Marc Tramier
- Université Rennes, Centre National de la recherche scientifique, IGDR (Genetics and Development Institute of Rennes), Unité mixte de receherche 6290, Rennes, France
| | - Christophe Zimmer
- Imaging and Modeling Unit, Department of Computational Biology, Institut Pasteur, Paris, France
- Rudolf Virchow Center, University of Würzburg, Würzburg, Germany
| | - Chiara Zurzolo
- Institut Pasteur, Unité de Trafic Membranaire et Pathogenèse, Paris, France
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
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2
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Xu Y, Sun L, Ghiggino KP, Smith TA. Resolving conjugated polymer film morphology with polarised transmission and time-resolved emission microscopy. Methods Appl Fluoresc 2024; 12:035004. [PMID: 38537297 DOI: 10.1088/2050-6120/ad388f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 03/27/2024] [Indexed: 04/17/2024]
Abstract
The alignment of chromophores plays a crucial role in determining the optoelectronic properties of materials. Such alignment can make interpretation of fluorescence anisotropy microscopy (FAM) images somewhat ambiguous. The time-resolved emission behaviour can also influence the fluorescence anisotropy. This is particularly the case when probing excitation energy migration between chromophores in a condensed phase. Ideally information concerning the chromophoric alignment, emission decay kinetics and fluorescence anisotropy can be recorded and correlated. We report on the use of polarised transmission imaging (PTI) coupled with both steady-state and time-resolved FAM to enable accurate identification of chromophoric alignment and morphology in thin films of a conjugated polydiarylfluorene. We show that the combination of these three imaging modes presents a comprehensive methodology for investigating the alignment and morphology of chromophores in thin films, particularly for accurately mapping the distribution of amorphous and crystalline phases within the thin films, offering valuable insights for the design and optimization of materials with enhanced optoelectronic performance.
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Affiliation(s)
- Yang Xu
- Ultrafast and Microspectroscopy Laboratories, School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Lili Sun
- Centre for Supramolecular Optoelectronics (CSO), School of Flexible Electronics (Future Technologies) and Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), Nanjing 211816, People's Republic of China
| | - Kenneth P Ghiggino
- Ultrafast and Microspectroscopy Laboratories, School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Trevor A Smith
- Ultrafast and Microspectroscopy Laboratories, School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
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3
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Whiting R, Stanton S, Kucheriava M, Smith AR, Pitts M, Robertson D, Kammer J, Li Z, Fologea D. Hypo-Osmotic Stress and Pore-Forming Toxins Adjust the Lipid Order in Sheep Red Blood Cell Membranes. MEMBRANES 2023; 13:620. [PMID: 37504986 PMCID: PMC10385129 DOI: 10.3390/membranes13070620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 06/07/2023] [Accepted: 06/22/2023] [Indexed: 07/29/2023]
Abstract
Lipid ordering in cell membranes has been increasingly recognized as an important factor in establishing and regulating a large variety of biological functions. Multiple investigations into lipid organization focused on assessing ordering from temperature-induced phase transitions, which are often well outside the physiological range. However, particular stresses elicited by environmental factors, such as hypo-osmotic stress or protein insertion into membranes, with respect to changes in lipid status and ordering at constant temperature are insufficiently described. To fill these gaps in our knowledge, we exploited the well-established ability of environmentally sensitive membrane probes to detect intramembrane changes at the molecular level. Our steady state fluorescence spectroscopy experiments focused on assessing changes in optical responses of Laurdan and diphenylhexatriene upon exposure of red blood cells to hypo-osmotic stress and pore-forming toxins at room temperature. We verified our utilized experimental systems by a direct comparison of the results with prior reports on artificial membranes and cholesterol-depleted membranes undergoing temperature changes. The significant changes observed in the lipid order after exposure to hypo-osmotic stress or pore-forming toxins resembled phase transitions of lipids in membranes, which we explained by considering the short-range interactions between membrane components and the hydrophobic mismatch between membrane thickness and inserted proteins. Our results suggest that measurements of optical responses from the membrane probes constitute an appropriate method for assessing the status of lipids and phase transitions in target membranes exposed to mechanical stresses or upon the insertion of transmembrane proteins.
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Affiliation(s)
- Rose Whiting
- Department of Physics, Boise State University, Boise, ID 83725, USA
- Biomolecular Sciences Graduate Program, Boise State University, Boise, ID 83725, USA
| | - Sevio Stanton
- Department of Physics, Boise State University, Boise, ID 83725, USA
| | | | - Aviana R Smith
- Department of Physics, Boise State University, Boise, ID 83725, USA
| | - Matt Pitts
- Department of Physics, Boise State University, Boise, ID 83725, USA
- Biomolecular Sciences Graduate Program, Boise State University, Boise, ID 83725, USA
| | - Daniel Robertson
- Department of Physics, Boise State University, Boise, ID 83725, USA
| | - Jacob Kammer
- Department of Physics, Boise State University, Boise, ID 83725, USA
- Department of Family Medicine, Idaho College of Osteopathic Medicine, Meridian, ID 83642, USA
| | - Zhiyu Li
- Department of Physics, Boise State University, Boise, ID 83725, USA
| | - Daniel Fologea
- Department of Physics, Boise State University, Boise, ID 83725, USA
- Biomolecular Sciences Graduate Program, Boise State University, Boise, ID 83725, USA
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4
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Refinement of Singer-Nicolson fluid-mosaic model by microscopy imaging: Lipid rafts and actin-induced membrane compartmentalization. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184093. [PMID: 36423676 DOI: 10.1016/j.bbamem.2022.184093] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 11/09/2022] [Accepted: 11/10/2022] [Indexed: 11/22/2022]
Abstract
This year celebrates the 50th anniversary of the Singer-Nicolson fluid mosaic model for biological membranes. The next level of sophistication we have achieved for understanding plasma membrane (PM) structures, dynamics, and functions during these 50 years includes the PM interactions with cortical actin filaments and the partial demixing of membrane constituent molecules in the PM, particularly raft domains. Here, first, we summarize our current knowledge of these two structures and emphasize that they are interrelated. Second, we review the structure, molecular dynamics, and function of raft domains, with main focuses on raftophilic glycosylphosphatidylinositol-anchored proteins (GPI-APs) and their signal transduction mechanisms. We pay special attention to the results obtained by single-molecule imaging techniques and other advanced microscopy methods. We also clarify the limitations of present optical microscopy methods for visualizing raft domains, but emphasize that single-molecule imaging techniques can "detect" raft domains associated with molecules of interest in the PM.
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5
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Single-Molecule Imaging of Ganglioside Probes in Living Cell Plasma Membranes. Methods Mol Biol 2023; 2613:215-227. [PMID: 36587082 DOI: 10.1007/978-1-0716-2910-9_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Gangliosides play a variety of physiological roles and are one of the most important lipid raft constituents. However, their dynamic behaviors have scarcely been investigated in living cells because of the lack of fluorescent probes that behave like their parental molecules. Recently, fluorescent ganglioside probes that mimic native ganglioside behaviors have been developed. In this chapter, I discuss the recent advances in research related to the lateral localization and dynamic behaviors of gangliosides in the plasma membranes of living cells.
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6
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Barrantes FJ. Fluorescence microscopy imaging of a neurotransmitter receptor and its cell membrane lipid milieu. Front Mol Biosci 2022; 9:1014659. [PMID: 36518846 PMCID: PMC9743973 DOI: 10.3389/fmolb.2022.1014659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 11/01/2022] [Indexed: 05/02/2024] Open
Abstract
Hampered by the diffraction phenomenon, as expressed in 1873 by Abbe, applications of optical microscopy to image biological structures were for a long time limited to resolutions above the ∼200 nm barrier and restricted to the observation of stained specimens. The introduction of fluorescence was a game changer, and since its inception it became the gold standard technique in biological microscopy. The plasma membrane is a tenuous envelope of 4 nm-10 nm in thickness surrounding the cell. Because of its highly versatile spectroscopic properties and availability of suitable instrumentation, fluorescence techniques epitomize the current approach to study this delicate structure and its molecular constituents. The wide spectral range covered by fluorescence, intimately linked to the availability of appropriate intrinsic and extrinsic probes, provides the ability to dissect membrane constituents at the molecular scale in the spatial domain. In addition, the time resolution capabilities of fluorescence methods provide complementary high precision for studying the behavior of membrane molecules in the time domain. This review illustrates the value of various fluorescence techniques to extract information on the topography and motion of plasma membrane receptors. To this end I resort to a paradigmatic membrane-bound neurotransmitter receptor, the nicotinic acetylcholine receptor (nAChR). The structural and dynamic picture emerging from studies of this prototypic pentameric ligand-gated ion channel can be extrapolated not only to other members of this superfamily of ion channels but to other membrane-bound proteins. I also briefly discuss the various emerging techniques in the field of biomembrane labeling with new organic chemistry strategies oriented to applications in fluorescence nanoscopy, the form of fluorescence microscopy that is expanding the depth and scope of interrogation of membrane-associated phenomena.
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Affiliation(s)
- Francisco J. Barrantes
- Biomedical Research Institute (BIOMED), Catholic University of Argentina (UCA)–National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
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7
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Cui J, Jin H, Zhan W. Enzyme-Free Liposome Active Motion via Asymmetrical Lipid Efflux. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:11468-11477. [PMID: 36084317 DOI: 10.1021/acs.langmuir.2c01866] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
As a class of biocompatible, water-dispersed colloids, liposomes have found widespread applications ranging from food to drug delivery. Adding mobility to these colloids, i.e., liposome micromotors, represents an attractive approach to next-generation liposome carriers with enhanced functionality and effectiveness. Currently, it remains unclear as to the scope of material features useful for building liposome micromotors or how they may differ functionally from their inorganic/polymer counterparts. In this work, we demonstrate liposome active motion taking advantage of mainly a pair of intrinsic material properties associated with these assemblies: lipid phase separation and extraction. We show that global phase separation of ternary lipid systems (such as DPPC/DOPC/cholesterol) within individual liposomes yields stable Janus particles with two distinctive liquid domains. While these anisotropic liposomes undergo pure Brownian diffusion in water, similar to their homogeneous analogues, adding extracting agents, cyclodextrins, to the system triggers asymmetrical cholesterol efflux about the liposomes, setting the latter into active motion. We present detailed analyses of liposome movement and cholesterol extraction kinetics to establish their correlation. We explore various experimental parameters as well as mechanistic details to account for such motion. Our results highlight the rich possibility to hierarchically design lipid-based artificial motors, from individual lipids, to their organization, surface chemistry, and interfacial mechanics.
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Affiliation(s)
- Jinyan Cui
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, United States
| | - Hui Jin
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, United States
| | - Wei Zhan
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, United States
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8
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Priyanka Damera D, Nag A. Exploring the membrane fluidity of phenyl boronic acid functionalized polymersomes using the FRAP technique and their application in the pH-sensitive release of curcumin. NEW J CHEM 2022. [DOI: 10.1039/d2nj01330d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
FRAP study to examine alterations in the membrane fluidity of functionalized polymersomes and pH responsive targeted delivery of curcumin.
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Affiliation(s)
| | - Amit Nag
- Department of Chemistry, BITS-Pilani Hyderabad Campus, Hyderabad, 500078, India
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9
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Adrien V, Rayan G, Astafyeva K, Broutin I, Picard M, Fuchs P, Urbach W, Taulier N. How to best estimate the viscosity of lipid bilayers. Biophys Chem 2021; 281:106732. [PMID: 34844029 DOI: 10.1016/j.bpc.2021.106732] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/19/2021] [Accepted: 11/19/2021] [Indexed: 11/02/2022]
Abstract
The viscosity of lipid bilayers is a property relevant to biological function, as it affects the diffusion of membrane macromolecules. To determine its value, and hence portray the membrane, various literature-reported techniques lead to significantly different results. Herein we compare the results issuing from two widely used techniques to determine the viscosity of membranes: the Fluorescence Lifetime Imaging Microscopy (FLIM), and Fluorescence Recovery After Photobleaching (FRAP). FLIM relates the time of rotation of a molecular rotor inserted into the membrane to the macroscopic viscosity of a fluid. Whereas FRAP measures molecular diffusion coefficients. This approach is based on a hydrodynamic model connecting the mobility of a membrane inclusion to the viscosity of the membrane. We show that: This article emphasizes the pitfalls to be avoided and the rules to be observed in order to obtain a value of the bilayer viscosity that characterizes the bilayer instead of interactions between the bilayer and the embedded probe.
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Affiliation(s)
- Vladimir Adrien
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, F-75005 Paris, France; Université de Paris, CNRS, Laboratoire CiTCoM, 75006 Paris, France; Sorbonne Université, AP-HP Department of Psychiatry, Hôpital Saint-Antoine, Paris, France
| | - Gamal Rayan
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, F-75005 Paris, France.
| | - Ksenia Astafyeva
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, F-75005 Paris, France
| | - Isabelle Broutin
- Université de Paris, CNRS, Laboratoire CiTCoM, 75006 Paris, France
| | - Martin Picard
- Université de Paris, Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS UMR 7099, F-75005 Paris, France; Institut de Biologie Physico-Chimique, Fondation Edmond de Rothschild pour le développement de la recherche Scientifique, F-75005 Paris, France
| | - Patrick Fuchs
- Sorbonne Université, Ecole Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules (LBM), 75005 Paris, France; Université de Paris, UFR Sciences du Vivant, 75013 Paris, France
| | - Wladimir Urbach
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, F-75005 Paris, France; Sorbonne Université, CNRS, INSERM, Laboratoire d'Imagerie Biomédicale, LIB, F-75006 Paris, France
| | - Nicolas Taulier
- Sorbonne Université, CNRS, INSERM, Laboratoire d'Imagerie Biomédicale, LIB, F-75006 Paris, France
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10
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Kusumi A, Fujiwara TK, Tsunoyama TA, Kasai RS, Liu AA, Hirosawa KM, Kinoshita M, Matsumori N, Komura N, Ando H, Suzuki KGN. Defining raft domains in the plasma membrane. Traffic 2021; 21:106-137. [PMID: 31760668 DOI: 10.1111/tra.12718] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 01/03/2023]
Abstract
Many plasma membrane (PM) functions depend on the cholesterol concentration in the PM in strikingly nonlinear, cooperative ways: fully functional in the presence of physiological cholesterol levels (35~45 mol%), and nonfunctional below 25 mol% cholesterol; namely, still in the presence of high concentrations of cholesterol. This suggests the involvement of cholesterol-based complexes/domains formed cooperatively. In this review, by examining the results obtained by using fluorescent lipid analogs and avoiding the trap of circular logic, often found in the raft literature, we point out the fundamental similarities of liquid-ordered (Lo)-phase domains in giant unilamellar vesicles, Lo-phase-like domains formed at lower temperatures in giant PM vesicles, and detergent-resistant membranes: these domains are formed by cooperative interactions of cholesterol, saturated acyl chains, and unsaturated acyl chains, in the presence of >25 mol% cholesterol. The literature contains evidence, indicating that the domains formed by the same basic cooperative molecular interactions exist and play essential roles in signal transduction in the PM. Therefore, as a working definition, we propose that raft domains in the PM are liquid-like molecular complexes/domains formed by cooperative interactions of cholesterol with saturated acyl chains as well as unsaturated acyl chains, due to saturated acyl chains' weak multiple accommodating interactions with cholesterol and cholesterol's low miscibility with unsaturated acyl chains and TM proteins. Molecules move within raft domains and exchange with those in the bulk PM. We provide a logically established collection of fluorescent lipid probes that preferentially partition into raft and non-raft domains, as defined here, in the PM.
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Affiliation(s)
- Akihiro Kusumi
- Membrane Cooperativity Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Okinawa, Japan.,Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto, Japan
| | - Takahiro K Fujiwara
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto, Japan
| | - Taka A Tsunoyama
- Membrane Cooperativity Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Okinawa, Japan
| | - Rinshi S Kasai
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - An-An Liu
- Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin, P. R. China
| | - Koichiro M Hirosawa
- Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, Gifu, Japan
| | - Masanao Kinoshita
- Department of Chemistry, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Nobuaki Matsumori
- Department of Chemistry, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Naoko Komura
- Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, Gifu, Japan
| | - Hiromune Ando
- Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, Gifu, Japan
| | - Kenichi G N Suzuki
- Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, Gifu, Japan
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11
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Park S, Sut TN, Ma GJ, Parikh AN, Cho NJ. Crystallization of Cholesterol in Phospholipid Membranes Follows Ostwald’s Rule of Stages. J Am Chem Soc 2020; 142:21872-21882. [DOI: 10.1021/jacs.0c10674] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Soohyun Park
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore
| | - Tun Naw Sut
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore
| | - Gamaliel Junren Ma
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore
| | - Atul N. Parikh
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore
- Department of Biomedical Engineering, University of California, Davis, Davis, California 95616, United States
| | - Nam-Joon Cho
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore
- Department of Biomedical Engineering, University of California, Davis, Davis, California 95616, United States
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12
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Kinoshita M, Kyo T, Matsumori N. Assembly formation of minor dihydrosphingomyelin in sphingomyelin-rich ordered membrane domains. Sci Rep 2020; 10:11794. [PMID: 32678223 PMCID: PMC7366691 DOI: 10.1038/s41598-020-68688-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 06/18/2020] [Indexed: 11/22/2022] Open
Abstract
The lipidome of mammalian cells not only contain sphingomyelin (SM) but also, as a minor component, dihydrosphongomyelin (DHSM), in which the double bond at C4–C5 in the sphingosine base is reduced to a single-bond linkage. It has been indicated that DHSM forms ordered domains more effectively than SM due to its greater potential to induce intermolecular hydrogen bonds. However, direct information on partition and dynamic behaviors of DHSM in raft-like liquid-ordered (Lo) and non-raft-like liquid-disordered (Ld) phase-segregated membranes has been lacking. In the present study, we prepared fluorescent derivatives of DHSM and compared their behaviors to those of fluorescent SM and phosphatidylcholine (PC) derivatives. Fluorescence microscopy showed that DHSM is more preferentially localized to the Lo domains in the Lo/Ld phase-segregated giant unilamellar vesicles than SM and PC. Most importantly, diffusion coefficient measurements indicated that DHSM molecules form DHSM-condensed assembly inside the SM-rich Lo domain of the SM/dioleoylphosphatidylcholine/cholesterol system even when DHSM accounts for 1–3.3 mol% of total lipids. Such heterogeneous distribution of DHSM in the SM-rich Lo domains was further confirmed by inter-lipid FRET experiments. This study provides new insights into the biological functions and significance of minor component DHSM in lipid rafts.
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Affiliation(s)
- Masanao Kinoshita
- Department of Chemistry, Graduate School of Science, Kyushu University, Motooka 744, Nishi-ku, Fukuoka, 819-0395, Japan.
| | - Takumi Kyo
- Department of Chemistry, Graduate School of Science, Kyushu University, Motooka 744, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Nobuaki Matsumori
- Department of Chemistry, Graduate School of Science, Kyushu University, Motooka 744, Nishi-ku, Fukuoka, 819-0395, Japan.
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13
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Carro MDLM, Peñalva DA, Antollini SS, Hozbor FA, Buschiazzo J. Cholesterol and desmosterol incorporation into ram sperm membrane before cryopreservation: Effects on membrane biophysical properties and sperm quality. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183357. [PMID: 32416195 DOI: 10.1016/j.bbamem.2020.183357] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 04/15/2020] [Accepted: 05/10/2020] [Indexed: 11/24/2022]
Abstract
Ram sperm are particularly sensitive to freeze-thawing mainly due to their lipid composition, limiting their use in artificial insemination programs. We evaluated the extent of cholesterol and desmosterol incorporation into ram sperm through incubation with increasing concentrations of methyl-β-cyclodextrin (MβCD)-sterol complexes, and its effect on membrane biophysical properties, membrane lateral organization and cryopreservation outcome. Sterols were effectively incorporated into the sperm membrane at 10 and 25 mM MβCD-sterols, similarly increasing membrane lipid order at physiological temperature and during temperature decrease. Differential ordering effect of sterols in ternary-mixture model membranes revealed a reduced tendency of desmosterol of segregating into ordered domains. Live cell imaging of fluorescent cholesterol showed sterol incorporation and evidenced the presence of sperm sub-populations compatible with different sterol contents and a high concentration of sterol rich-ordered domains mainly at the acrosome plasma membrane. Lateral organization of the plasma membrane, assessed by identification of GM1-related rafts, was preserved after sterol incorporation except when high levels of sterols (25 mM MβCD-desmosterol) were incorporated. Ram sperm incubation with 10 mM MβCD-sterols prior to cryopreservation in a cholesterol-free extender improved sperm quality parameters after cooling and freezing. While treatment with 10 mM MβCD-cholesterol increased sperm motility, membrane integrity and tolerance to osmotic stress after thawing, incorporation of desmosterol increased the ability of ram sperm to overcome osmotic stress. Our research provides evidence on the effective incorporation and biophysical behavior of cholesterol and desmosterol in ram sperm membranes and on their consequences in improving functional parameters of sperm after temperature decrease and freezing.
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Affiliation(s)
- María de Las Mercedes Carro
- Laboratorio Biotecnología de la Reproducción, Departamento de Producción Animal, Instituto Nacional de Tecnología Agropecuaria (INTA), EEA Balcarce, Ruta 226 km 73.5, 7620 Balcarce, Buenos Aires, Argentina
| | - Daniel A Peñalva
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad Nacional del Sur (UNS), Camino La Carrindanga Km 7, 8000 Bahía Blanca, Argentina; Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Av. Alem 1253, 8000 Bahía Blanca, Argentina
| | - Silvia S Antollini
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad Nacional del Sur (UNS), Camino La Carrindanga Km 7, 8000 Bahía Blanca, Argentina; Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Av. Alem 1253, 8000 Bahía Blanca, Argentina
| | - Federico A Hozbor
- Laboratorio Biotecnología de la Reproducción, Departamento de Producción Animal, Instituto Nacional de Tecnología Agropecuaria (INTA), EEA Balcarce, Ruta 226 km 73.5, 7620 Balcarce, Buenos Aires, Argentina
| | - Jorgelina Buschiazzo
- Laboratorio Biotecnología de la Reproducción, Departamento de Producción Animal, Instituto Nacional de Tecnología Agropecuaria (INTA), EEA Balcarce, Ruta 226 km 73.5, 7620 Balcarce, Buenos Aires, Argentina.
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14
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Sibold J, Tewaag VE, Vagedes T, Mey I, Steinem C. Phase separation in pore-spanning membranes induced by differences in surface adhesion. Phys Chem Chem Phys 2020; 22:9308-9315. [DOI: 10.1039/d0cp00335b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A porous scaffold providing different adhesion energies alters the behaviour of coexisting phases in lipid membranes considerably.
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Affiliation(s)
- Jeremias Sibold
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Vera E. Tewaag
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Thomas Vagedes
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Ingo Mey
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Claudia Steinem
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
- Max Planck Institute for Dynamics and Self-Organization
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15
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Reinholdt P, Wind S, Wüstner D, Kongsted J. Computational Characterization of a Cholesterol-Based Molecular Rotor in Lipid Membranes. J Phys Chem B 2019; 123:7313-7326. [PMID: 31381343 DOI: 10.1021/acs.jpcb.9b04967] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Biophysical properties of cellular membranes critically depend on their content of cholesterol and its interaction with various other lipid species. Cholesterol-dependent friction at the nanoscale can be studied with molecular rotors, whose quantum yield depends on rotational dynamics of functional groups during their excited state lifetime. Here, we present a detailed computational analysis of a phenyl-BODIPY-linked cholesterol based molecular rotor in direct comparison with the well-known TopFluor-cholesterol. We describe a new parametrization strategy of force field parameters for the BODIPY moiety and carry out extensive molecular dynamics simulations of the probe in membranes in the absence or presence of cholesterol. Our study quantifies the extent of membrane perturbation by these probes, analyzes their tilting resistance in the bilayer and derives dynamic properties directly related to the rotor propensity. We show that phenyl-BODIPY-cholesterol bears potential as a cholesterol-dependent molecular rotor to report about microviscosity of sterol-containing model and cell membranes.
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Affiliation(s)
- Peter Reinholdt
- Department of Physics, Chemistry and Pharmacy , University of Southern Denmark , Campusvej 55 , DK-5230 Odense M , Denmark
| | - Signe Wind
- Department of Physics, Chemistry and Pharmacy , University of Southern Denmark , Campusvej 55 , DK-5230 Odense M , Denmark
| | - Daniel Wüstner
- Department of Biochemistry and Molecular Biology , University of Southern Denmark , Campusvej 55 , DK-5230 Odense M , Denmark
| | - Jacob Kongsted
- Department of Physics, Chemistry and Pharmacy , University of Southern Denmark , Campusvej 55 , DK-5230 Odense M , Denmark
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16
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Matsufuji T, Kinoshita M, Matsumori N. Preparation and Membrane Distribution of Fluorescent Derivatives of Ceramide. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:2392-2398. [PMID: 30608698 DOI: 10.1021/acs.langmuir.8b03176] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Ceramide is a bioactive lipid with significant roles in several biological processes including cell proliferation, apoptosis, and raft formation. Although fluorescent derivatives of ceramide are required to probe the behavior of ceramide in cells and cell membranes, commercial fluorescent ceramide derivatives do not reproduce the membrane behavior of native ceramide because of the introduction of bulky fluorophores in the acyl chain. Recently, we developed novel fluorescent analogs of sphingomyelin in which the hydrophilic fluorophores, ATTO488 and ATTO594, are attached to the polar head of sphingomyelin via a nonaethylene glycol linker and demonstrated that their partition and dynamic behaviors in bilayer membranes are similar to native sphingomyelin. In this report, by extending the concept used for the development of fluorescent analogs of sphingomyelin, we prepared novel fluorescent ceramides that exhibit membrane behaviors similar to native ceramide and succeeded in visualizing ceramide-rich membrane domains segregated from ceramide-poor domains.
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Affiliation(s)
- Takaaki Matsufuji
- Department of Chemistry, Graduate School of Science , Kyushu University , 744 Motooka , Nishi-ku, Fukuoka 819-0395 , Japan
| | - Masanao Kinoshita
- Department of Chemistry, Graduate School of Science , Kyushu University , 744 Motooka , Nishi-ku, Fukuoka 819-0395 , Japan
| | - Nobuaki Matsumori
- Department of Chemistry, Graduate School of Science , Kyushu University , 744 Motooka , Nishi-ku, Fukuoka 819-0395 , Japan
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17
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Hanashima S, Ibata Y, Watanabe H, Yasuda T, Tsuchikawa H, Murata M. Side-chain deuterated cholesterol as a molecular probe to determine membrane order and cholesterol partitioning. Org Biomol Chem 2019; 17:8601-8610. [DOI: 10.1039/c9ob01342c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
24dCho, which perfectly retains the cholesterol's membrane properties, was developed to examine cholesterol's interactions and membrane partitions using solid state 2H NMR.
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Affiliation(s)
- Shinya Hanashima
- Department of Chemistry
- Graduate School of Science
- Osaka University
- Toyonaka
- Japan
| | - Yuki Ibata
- Department of Chemistry
- Graduate School of Science
- Osaka University
- Toyonaka
- Japan
| | - Hirofumi Watanabe
- Department of Chemistry
- Graduate School of Science
- Osaka University
- Toyonaka
- Japan
| | - Tomokazu Yasuda
- Department of Chemistry
- Graduate School of Science
- Osaka University
- Toyonaka
- Japan
| | - Hiroshi Tsuchikawa
- Department of Chemistry
- Graduate School of Science
- Osaka University
- Toyonaka
- Japan
| | - Michio Murata
- Department of Chemistry
- Graduate School of Science
- Osaka University
- Toyonaka
- Japan
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18
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O' Connor D, Byrne A, Keyes TE. Linker length in fluorophore–cholesterol conjugates directs phase selectivity and cellular localisation in GUVs and live cells. RSC Adv 2019; 9:22805-22816. [PMID: 35514503 PMCID: PMC9067298 DOI: 10.1039/c9ra03905h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 07/14/2019] [Indexed: 01/07/2023] Open
Abstract
Lipid membrane fluorescent probes that are both domain-selective and compatible with demanding microscopy methods are crucial to elucidate the presence and function of rafts and domains in cells and biophysical models. Whereas targeting fluorescent probes to liquid-disordered (Ld) domains is relatively facile, it is far more difficult to direct probes with high selectivity to liquid-ordered (Lo) domains. Here, a simple, one-pot approach to probe–cholesterol conjugation is described using Steglich esterification to synthesise two identical BODIPY derivatives that differ only in the length of the aliphatic chain between the dye and cholesterol. In the first, BODIPY-Ar-Chol, the probe and cholesterol were directly ester linked and in the second BODIPY-Ahx-Chol, a hexyl linker separated probe from cholesterol. Uptake and distribution of each probe was compared in ternary, phase separated giant unilamellar vesicles (GUVs) using a commercial Ld marker as a reference. BODIPY-Ar-Chol targets almost exclusively the Ld domains with selectivity of >90% whereas by contrast introducing the C6 linker between the probe and cholesterol drove the probe to Lo with excellent selectivity (>80%). The profound impact of the linker length extended also to uptake and distribution in live mammalian cells. BODIPY-Ahx-Chol associates strongly with the plasma membrane where it partitioned preferably into opposing micron dimensioned do-mains to a commercial Ld marker and its concentration at the membrane was reduced by cyclodextrin treatment of the cells. By contrast the BODIPY-Ahx-Chol permeated the membrane and localised strongly to lipid droplets within the cell. The data demonstrates the profound influence of linker length in cholesterol bioconjugates in directing the probe. By inserting a hexyl linker between a BODIPY probe and cholesterol pendant, the localization of the probe at ternary phase separated GUVs switches from Ld to Lo domains with high specificity.![]()
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Affiliation(s)
- Darragh O' Connor
- School of Chemical Sciences
- National Centre for Sensor Research
- Dublin City University
- Dublin 9
- Ireland
| | - Aisling Byrne
- School of Chemical Sciences
- National Centre for Sensor Research
- Dublin City University
- Dublin 9
- Ireland
| | - Tia E. Keyes
- School of Chemical Sciences
- National Centre for Sensor Research
- Dublin City University
- Dublin 9
- Ireland
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19
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Nyholm TKM, Jaikishan S, Engberg O, Hautala V, Slotte JP. The Affinity of Sterols for Different Phospholipid Classes and Its Impact on Lateral Segregation. Biophys J 2018; 116:296-307. [PMID: 30583790 DOI: 10.1016/j.bpj.2018.11.3135] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 11/15/2018] [Accepted: 11/19/2018] [Indexed: 10/27/2022] Open
Abstract
Cholesterol is an essential molecule in the membranes of mammalian cells. It is known to be distributed heterogeneously within the cells, between the bilayer leaflets, as well as between lateral domains within the bilayer. However, we do not know exactly how cholesterol is distributed and what forces drive this sorting process because it extremely difficult to study using currently available methods. To further elucidate this distribution, we measured how cholesterol partitions between different phospholipid (PL) environments using different methods based on cholesterol, TopFluor-cholesterol, and cholesta-5,7,9(11)-triene-3-β-ol. Based on the obtained relative partition coefficients, we made predictions regarding how cholesterol would be distributed between lateral domains and between the inner and outer leaflets of the plasma membrane. In addition, using a trans-parinaric acid fluorescence-based method, we tested how cholesterol could influence lateral segregation through its interaction with unsaturated PLs with different headgroups. The results showed that the lower the affinity of cholesterol was for the different unsaturated PLs, the more cholesterol stimulated lateral segregation in a ternary bilayer of unsaturated PL/N-palmitoyl-D-erythro-sphingomyelin and cholesterol. Overall, the results indicate that both the distribution of cholesterol between different lipid environments and the impact of cholesterol on lateral segregation can be predicted relatively accurately from determined relative partition coefficients.
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Affiliation(s)
- Thomas K M Nyholm
- Biochemistry, Faculty of Science and Engineering, Abo Akademi University, Turku, Finland.
| | - Shishir Jaikishan
- Biochemistry, Faculty of Science and Engineering, Abo Akademi University, Turku, Finland
| | - Oskar Engberg
- Biochemistry, Faculty of Science and Engineering, Abo Akademi University, Turku, Finland
| | - Victor Hautala
- Biochemistry, Faculty of Science and Engineering, Abo Akademi University, Turku, Finland
| | - J Peter Slotte
- Biochemistry, Faculty of Science and Engineering, Abo Akademi University, Turku, Finland
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20
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Cong A, Pimenta RML, Lee HB, Mereddy V, Holy J, Heikal AA. Two-photon fluorescence lifetime imaging of intrinsic NADH in three-dimensional tumor models. Cytometry A 2018; 95:80-92. [PMID: 30343512 DOI: 10.1002/cyto.a.23632] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 09/06/2018] [Accepted: 09/11/2018] [Indexed: 12/20/2022]
Abstract
Most studies using intrinsic NAD(P)H as biomarkers for energy metabolism and mitochondrial anomalies have been conducted in routine two-dimensional (2D) cell culture formats. Cellular metabolism and cell behavior, however, can be significantly different in 2D cultures from that in vivo. As a result, there are emerging interests in integrating noninvasive, quantitative imaging techniques of NAD(P)H with in vivo-like three-dimensional (3D) models. The overall features and metabolic responses of the murine breast cancer cells line 4T1 in 2D cultures were compared with those in 3D collagen matrix using integrated optical micro-spectroscopy. The metabolic responses to two novel compounds, MD1 and TPPBr, that target metabolism by disrupting monocarboxylate transporters or oxidative phosphorylation (OXPHOS), respectively, were investigated using two-photon fluorescence lifetime imaging microscopy (2P-FLIM) of intracellular NAD(P)H in 2D and 3D cultures. 4T1 cells exhibit distinct behaviors in a collagenous 3D matrix from those in 2D culture, forming anastomosing multicellular networks and spherical acini in 3D culture, as opposed to simple flattened epithelial plaques in 2D culture. The cellular NAD(P)H in 3D collagen matrix exhibits a longer fluorescence lifetime as compared with 2D culture, which is attributed to an enhanced population of enzyme-bound NAD(P)H in the 3D culture. TPPBr induces mitochondrial hyperpolarization in 2D culture of 4T1 cells along with an enhanced free NAD(P)H population, which suggest an interference with OXPHOS. In contrast, 2P-FLIM of cellular NAD(P)H revealed an enhanced autofluorescence lifetime in 3D 4T1 cultures after MD1 treatment as compared with MD1-treated 2D culture and the control 3D culture. Physical and chemical microenvironmental signaling are critical factors in understanding how therapeutic compounds target cancer cells by disrupting their metabolic pathways. Integrating 2P-FLIM of intrinsic NAD(P)H with refined 3D tumor-matrix in vitro models promises to advance our understanding of the roles of metabolism and metabolic plasticity in tumor growth and metastatic behavior. © 2018 International Society for Advancement of Cytometry.
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Affiliation(s)
- Anh Cong
- Department of Chemistry and Biochemistry, Swenson College of Science and Engineering, University of Minnesota Duluth, Duluth, Minnesota
| | - Rafaela M L Pimenta
- Integrated Biosciences Graduate Program, Swenson College of Science and Engineering, University of Minnesota Duluth, Duluth, Minnesota
| | - Hong Bok Lee
- Department of Chemistry and Biochemistry, Swenson College of Science and Engineering, University of Minnesota Duluth, Duluth, Minnesota
| | - Venkatram Mereddy
- Department of Chemistry and Biochemistry, Swenson College of Science and Engineering, University of Minnesota Duluth, Duluth, Minnesota
| | - Jon Holy
- Department of Biomedical Sciences, Medical School, University of Minnesota Duluth, Duluth, Minnesota
| | - Ahmed A Heikal
- Department of Chemistry and Biochemistry, Swenson College of Science and Engineering, University of Minnesota Duluth, Duluth, Minnesota
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21
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Anastasius M, Luquain-Costaz C, Kockx M, Jessup W, Kritharides L. A critical appraisal of the measurement of serum 'cholesterol efflux capacity' and its use as surrogate marker of risk of cardiovascular disease. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:1257-1273. [PMID: 30305243 DOI: 10.1016/j.bbalip.2018.08.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 08/02/2018] [Accepted: 08/03/2018] [Indexed: 12/15/2022]
Abstract
The 'cholesterol efflux capacity (CEC)' assay is a simple in vitro measure of the capacities of individual sera to promote the first step of the reverse cholesterol transport pathway, the delivery of cellular cholesterol to plasma HDL. This review describes the cell biology of this model and critically assesses its application as a marker of cardiovascular risk. We describe the pathways for cell cholesterol export, current cell models used in the CEC assay with their limitations and consider the contribution that measurement of serum CEC provides to our understanding of HDL function in vivo.
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Affiliation(s)
- Malcolm Anastasius
- ANZAC Research Institute, Concord Repatriation General Hospital, University of Sydney, Sydney, NSW, Australia
| | | | - Maaike Kockx
- ANZAC Research Institute, Concord Repatriation General Hospital, University of Sydney, Sydney, NSW, Australia
| | - Wendy Jessup
- ANZAC Research Institute, Concord Repatriation General Hospital, University of Sydney, Sydney, NSW, Australia
| | - Leonard Kritharides
- ANZAC Research Institute, Concord Repatriation General Hospital, University of Sydney, Sydney, NSW, Australia; Cardiology Department, Concord Repatriation General Hospital, University of Sydney, Sydney, NSW, Australia.
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22
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Xiong Y, Zheng S, Zhu L, Guo H, Yang F. Novel liquid crystals with high fluorescence: Synthesis, mesomorphic and photophysical properties of cholesterol-triazine-BODIPY trimers. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2018.03.093] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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23
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Wang M, Liu Z, Zhan W. Janus Liposomes: Gel-Assisted Formation and Bioaffinity-Directed Clustering. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:7509-7518. [PMID: 29852065 DOI: 10.1021/acs.langmuir.8b00798] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This article reports a high-yield procedure for preparing microsized (giant) Janus liposomes via gel-assisted lipid swelling and clustering behavior of these liposomes directed by biotin-avidin affinity binding. Confocal fluorescence microscopy reveals in detail that these new lipid colloidal particles display broken symmetry and heterogeneous surface chemistry similar to other types of Janus particles. An optimized formation procedure is presented, which reproducibly yields large liposome populations dominated by a single-domain configuration. This work further demonstrates that biotin-conjugated 1,2-dioleoyl- sn-glycero-3-phosphoethanolamine preferentially partitions into the liquid-disordered phase of the lipid matrix, rendering these Janus liposomes asymmetrical binding capacity toward avidin. This affinity binding drives irreversible and domain-specific cluster formation among Janus liposomes, whose structure and size are found to depend on the domain configuration of individual liposomes and incubation time.
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Affiliation(s)
- Mingming Wang
- Department of Chemistry and Biochemistry , Auburn University , Auburn , Alabama 36849 , United States
| | - Zening Liu
- Department of Chemistry and Biochemistry , Auburn University , Auburn , Alabama 36849 , United States
| | - Wei Zhan
- Department of Chemistry and Biochemistry , Auburn University , Auburn , Alabama 36849 , United States
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24
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O’Connor D, Byrne A, Dolan C, Keyes TE. Phase partitioning, solvent-switchable BODIPY probes for high contrast cellular imaging and FCS. NEW J CHEM 2018. [DOI: 10.1039/c7nj04604a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lipophilic BODIPY fluorphores, in which the BODIPY core bears pendant dipyrido[3,2-a:2′,3′-c]phenazine (Dppz) or naphthyridyl and cholesterol substituents were designed and prepared as lipid probes for both liposomes and live cell imaging.
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Affiliation(s)
- Darragh O’Connor
- School of Chemical Sciences, National Centre for Sensor Research, Dublin City University
- Dublin 9
- Ireland
| | - Aisling Byrne
- School of Chemical Sciences, National Centre for Sensor Research, Dublin City University
- Dublin 9
- Ireland
| | - Ciarán Dolan
- School of Chemical Sciences, National Centre for Sensor Research, Dublin City University
- Dublin 9
- Ireland
| | - Tia E. Keyes
- School of Chemical Sciences, National Centre for Sensor Research, Dublin City University
- Dublin 9
- Ireland
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25
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Lee HB, Cong A, Leopold H, Currie M, Boersma AJ, Sheets ED, Heikal AA. Rotational and translational diffusion of size-dependent fluorescent probes in homogeneous and heterogeneous environments. Phys Chem Chem Phys 2018; 20:24045-24057. [DOI: 10.1039/c8cp03873b] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Macromolecular crowding effects on diffusion depend on the fluorophore structure, the concentration of crowding agents, and the technique employed.
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Affiliation(s)
- Hong Bok Lee
- Department of Chemistry and Biochemistry
- Swenson College of Science and Engineering
- University of Minnesota Duluth
- Duluth
- USA
| | - Anh Cong
- Department of Chemistry and Biochemistry
- Swenson College of Science and Engineering
- University of Minnesota Duluth
- Duluth
- USA
| | - Hannah Leopold
- Department of Chemistry and Biochemistry
- Swenson College of Science and Engineering
- University of Minnesota Duluth
- Duluth
- USA
| | - Megan Currie
- Department of Chemistry and Biochemistry
- Swenson College of Science and Engineering
- University of Minnesota Duluth
- Duluth
- USA
| | | | - Erin D. Sheets
- Department of Chemistry and Biochemistry
- Swenson College of Science and Engineering
- University of Minnesota Duluth
- Duluth
- USA
| | - Ahmed A. Heikal
- Department of Chemistry and Biochemistry
- Swenson College of Science and Engineering
- University of Minnesota Duluth
- Duluth
- USA
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26
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Sebastian B, Favero T, Dittrich PS. The Effects of Shear Force Transmission Across Vesicle Membranes. J Phys Chem Lett 2017; 8:6128-6134. [PMID: 29190425 PMCID: PMC6426246 DOI: 10.1021/acs.jpclett.7b02676] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We report a comprehensive study on mechanotransmission of shear forces across lipid bilayer membranes of giant unilamellar vesicles (GUVs). GUVs containing fluorescent tracer particles were immobilized on a microfluidic platform and exposed to shear flows. A method was developed for the visualization of three-dimensional flows at high precision by defocusing microscopy. We quantify the symmetry of external flow around the GUV and show its effects on vortex flows and luminal dynamics. With increasing asymmetry, luminal vortices merged while liquid exchange in between them increased. The effect of membrane composition was studied through addition of cholesterol. Mechanotransmission efficacy, quantified by the ratio of luminal flow to external flow, ranged from ε = 0.094 (0 mol % cholesterol) to ε = 0.043 (16 mol % cholesterol). Our findings give new cues to the mechanisms underlying the sensing of strength and spatial distribution of shear forces by cells and the impact of membrane composition.
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Affiliation(s)
- Bernhard Sebastian
- Department of Biosystems Science and Engineering, ETH Zurich,
Mattenstrasse 26, 4058 Basel, Switzerland
| | - Tobias Favero
- Department of Biosystems Science and Engineering, ETH Zurich,
Mattenstrasse 26, 4058 Basel, Switzerland
| | - Petra S. Dittrich
- Corresponding Author: Mailing address: ETH Zurich
Department of Biosystems Science and Engineering Mattenstrasse 26 CH-4058
Basel/Switzerland. Phone: +41 63 387 33 10;
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27
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Kinoshita M, Ano H, Murata M, Shigetomi K, Ikenouchi J, Matsumori N. Emphatic visualization of sphingomyelin-rich domains by inter-lipid FRET imaging using fluorescent sphingomyelins. Sci Rep 2017; 7:16801. [PMID: 29196620 PMCID: PMC5711942 DOI: 10.1038/s41598-017-16361-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 11/10/2017] [Indexed: 11/11/2022] Open
Abstract
Imaging the distribution of sphingomyelin (SM) in membranes is an important issue in lipid-raft research. Recently we developed novel fluorescent SM analogs that exhibit partition and dynamic behaviors similar to native SM, and succeeded in visualizing lateral domain-segregation between SM-rich liquid-ordered (Lo) and SM-poor liquid-disordered (Ld) domains. However, because the fluorescent contrast between these two domains depends directly on their partition ratio for the fluorescent SMs, domain-separation becomes indeterminate when the distribution difference is not great enough. In this study, we propose the use of inter-lipid Förster resonance energy transfer (FRET) imaging between fluorescent SMs to enhance the contrast of the two domains in cases in which the inter-domain difference in SM distribution is inadequate for conventional monochromic imaging. Our results demonstrate that inter-lipid FRET intensity was significantly higher in the Lo domain than in the Ld domain, resulting in a clear and distinguishable contrast between the two domains even in poorly phase-separated giant unilamellar vesicles. In addition, we show that inter-lipid FRET imaging is useful for selective visualization of highly condensed assemblies and/or clusters of SM molecules in living cell membranes. Thus, the inter-lipid FRET imaging technique can selectively emphasize the SM-condensed domains in both artificial and biological membranes.
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Affiliation(s)
- Masanao Kinoshita
- JST-ERATO Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan. .,Project Research Center for Fundamental Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan. .,Department of Chemistry, Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.
| | - Hikaru Ano
- JST-ERATO Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan.,Project Research Center for Fundamental Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan
| | - Michio Murata
- JST-ERATO Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan.,Project Research Center for Fundamental Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan.,Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan
| | - Kenta Shigetomi
- Department of Biology, Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Junichi Ikenouchi
- Department of Biology, Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Nobuaki Matsumori
- JST-ERATO Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan. .,Department of Chemistry, Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan. .,Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan.
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28
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Cholesterol added prior to vitrification on the cryotolerance of immature and in vitro matured bovine oocytes. PLoS One 2017; 12:e0184714. [PMID: 28910399 PMCID: PMC5598999 DOI: 10.1371/journal.pone.0184714] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 08/29/2017] [Indexed: 12/05/2022] Open
Abstract
This study examines whether incorporating cholesterol-loaded methyl-β-cyclodextrin (CLC) in the bovine oocyte plasma membrane improves oocyte tolerance to vitrification. In vitro matured oocytes were incubated with 2 mg/ml BODIPY-labeled CLC for different time intervals in FCS or PVA supplemented medium or exposed to different CLC concentrations to examine the subcellular localization of cholesterol by confocal microscopy live-cell imaging. Subsequently, the effects of optimized CLC concentrations and incubation times prior to vitrification on early embryo development were assessed. Then, we evaluated the effects of pretreatment with 2 mg/ml CLC for 30 min before the vitrification of immature (GV) and in vitro matured (MII) oocytes on developmental competence and gene expression. Our results indicate a high plasma membrane labeling intensity after 30 min of incubation with 2 mg/ml CLC for 30 min, regardless of the holding medium used. When oocytes were incubated with 1 mg/ml, 2 mg/ml and 3 mg/ml of CLC, intense labeling was observed at the plasma membrane after 40, 30 and 20 min, respectively. CLC pre-treatment before the vitrification of bovine oocytes did not affect subsequent cleavage and embryo development rates irrespective of CLC concentrations, incubation times or meiotic stage. However, pretreatment seems to improve the quality of embryos derived from vitrified oocytes, mainly when oocytes were vitrified at the GV stage.
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29
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Maiwald A, Bauer O, Gimpl G. Synthesis and characterization of a novel rhodamine labeled cholesterol reporter. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1099-1113. [PMID: 28257814 DOI: 10.1016/j.bbamem.2017.02.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 02/21/2017] [Accepted: 02/27/2017] [Indexed: 11/18/2022]
Abstract
We introduce the novel fluorescent cholesterol probe RChol in which a sulforhodamine group is linked to the sixth carbon atom of the steroid backbone of cholesterol. The same position has recently been selected to generate the fluorescent reporter 6-dansyl-cholestanol (DChol) and the photoreactive 6-azi-cholestanol. In comparison with DChol, RChol is brighter, much more photostable, and requires less energy for excitation, i.e. favorable conditions for microscopical imaging. RChol easily incorporates into methyl-β-cyclodextrin forming a water-soluble inclusion complex that acts as an efficient sterol donor for cells and membranes. Like cholesterol, RChol possesses a free 3'OH group, a prerequisite to undergo intracellular esterification. RChol was also able to support the growth of cholesterol auxotrophic cells and can therefore substitute for cholesterol as a major component of the plasma membrane. According to subcellular fractionation, slight amounts of RChol (~12%) were determined in low-density Triton-insoluble fractions whereas the majority of RChol was localized in non-rafts fractions. In phase-separated giant unilamellar vesicles, RChol preferentially partitions in liquid-disordered membrane domains. Intracellular RChol was transferred to extracellular sterol acceptors such as high density lipoproteins in a dose-dependent manner. Unlike DChol, RChol was not delivered to the cholesterol storage pathway. Instead, it translocated to endosomes/lysosomes with some transient contacts to peroxisomes. Thus, RChol is considered as a useful probe to study the endosomal/lysosomal pathway of cholesterol.
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Affiliation(s)
- Alexander Maiwald
- Institute of Pharmacy and Biochemistry, Gutenberg-University Mainz, Johann-Joachim Becherweg 30, D-55128 Mainz, Germany
| | - Olivia Bauer
- Institute of Pharmacy and Biochemistry, Gutenberg-University Mainz, Johann-Joachim Becherweg 30, D-55128 Mainz, Germany
| | - Gerald Gimpl
- Institute of Pharmacy and Biochemistry, Gutenberg-University Mainz, Johann-Joachim Becherweg 30, D-55128 Mainz, Germany.
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30
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Gaibelet G, Tercé F, Allart S, Lebrun C, Collet X, Jamin N, Orlowski S. Fluorescent probes for detecting cholesterol-rich ordered membrane microdomains: entangled relationships between structural analogies in the membrane and functional homologies in the cell. AIMS BIOPHYSICS 2017. [DOI: 10.3934/biophy.2017.1.121] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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31
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Osati S, Ali H, van Lier JE. BODIPY–steroid conjugates: Syntheses and biological applications. J PORPHYR PHTHALOCYA 2016. [DOI: 10.1142/s1088424616300019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BODIPY and aza-BODIPY fluorophores linked to steroids are being developed as multimodal-imaging agents to monitor the mechanism of action of biologically active components in living systems.
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Affiliation(s)
- Samira Osati
- Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001, 12th Avenue North, Sherbrooke QC J1H 5N4, Canada
| | - Hasrat Ali
- Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001, 12th Avenue North, Sherbrooke QC J1H 5N4, Canada
| | - Johan E. van Lier
- Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001, 12th Avenue North, Sherbrooke QC J1H 5N4, Canada
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32
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Anderson JL, Carten JD, Farber SA. Using fluorescent lipids in live zebrafish larvae: From imaging whole animal physiology to subcellular lipid trafficking. Methods Cell Biol 2016; 133:165-78. [PMID: 27263413 DOI: 10.1016/bs.mcb.2016.04.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Lipids serve essential functions in cells as signaling molecules, membrane components, and sources of energy. Defects in lipid metabolism are implicated in a number of pandemic human diseases, including diabetes, obesity, and hypercholesterolemia. Many aspects of how fatty acids and cholesterol are absorbed and processed by intestinal cells remain unclear and present a hurdle to developing approaches for disease prevention and treatment. Numerous studies have shown that the zebrafish is an excellent model for vertebrate lipid metabolism. In this chapter, we review commercially available fluorescent lipids that can be deployed in live zebrafish to better understand lipid signaling and metabolism. In this chapter, we present criteria one should consider when selecting specific fluorescent lipids for the study of digestive physiology or lipid metabolism in larval zebrafish.
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Affiliation(s)
- J L Anderson
- Carnegie Institution for Science, Baltimore, MD, United States
| | - J D Carten
- Carnegie Institution for Science, Baltimore, MD, United States
| | - S A Farber
- Carnegie Institution for Science, Baltimore, MD, United States
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33
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Dent MR, López-Duarte I, Dickson CJ, Geoghegan ND, Cooper JM, Gould IR, Krams R, Bull JA, Brooks NJ, Kuimova MK. Imaging phase separation in model lipid membranes through the use of BODIPY based molecular rotors. Phys Chem Chem Phys 2016; 17:18393-402. [PMID: 26104504 DOI: 10.1039/c5cp01937k] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
In order to fully understand the dynamics of processes within biological lipid membranes, it is necessary to possess an intimate knowledge of the physical state and ordering of lipids within the membrane. Here we report the use of three molecular rotors based on meso-substituted boron-dipyrrin (BODIPY) in combination with fluorescence lifetime spectroscopy to investigate the viscosity and phase behaviour of model lipid bilayers. In phase-separated giant unilamellar vesicles, we visualise both liquid-ordered (Lo) and liquid-disordered (Ld) phases using fluorescence lifetime imaging microscopy (FLIM), determining their associated viscosity values, and investigate the effect of composition on the viscosity of these phases. Additionally, we use molecular dynamics simulations to investigate the orientation of the BODIPY probes within the bilayer, as well as using molecular dynamics simulations and fluorescence correlation spectroscopy (FCS) to compare diffusion coefficients with those predicted from the fluorescence lifetimes of the probes.
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Affiliation(s)
- Michael R Dent
- Department of Chemistry, Imperial College London, Exhibition Road, London, SW7 2AZ, UK.
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34
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Imaging approaches for analysis of cholesterol distribution and dynamics in the plasma membrane. Chem Phys Lipids 2016; 199:106-135. [PMID: 27016337 DOI: 10.1016/j.chemphyslip.2016.03.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 03/04/2016] [Indexed: 11/21/2022]
Abstract
Cholesterol is an important lipid component of the plasma membrane (PM) of mammalian cells, where it is involved in control of many physiological processes, such as endocytosis, cell migration, cell signalling and surface ruffling. In an attempt to explain these functions of cholesterol, several models have been put forward about cholesterol's lateral and transbilayer organization in the PM. In this article, we review imaging techniques developed over the last two decades for assessing the distribution and dynamics of cholesterol in the PM of mammalian cells. Particular focus is on fluorescence techniques to study the lateral and inter-leaflet distribution of suitable cholesterol analogues in the PM of living cells. We describe also several methods for determining lateral cholesterol dynamics in the PM including fluorescence recovery after photobleaching (FRAP), fluorescence correlation spectroscopy (FCS), single particle tracking (SPT) and spot variation FCS coupled to stimulated emission depletion (STED) microscopy. For proper interpretation of such measurements, we provide some background in probe photophysics and diffusion phenomena occurring in cell membranes. In particular, we show the equivalence of the reaction-diffusion approach, as used in FRAP and FCS, and continuous time random walk (CTRW) models, as often invoked in SPT studies. We also discuss mass spectrometry (MS) based imaging of cholesterol in the PM of fixed cells and compare this method with fluorescence imaging of sterols. We conclude that evidence from many experimental techniques converges towards a model of a homogeneous distribution of cholesterol with largely free and unhindered diffusion in both leaflets of the PM.
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35
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Ogawa Y, Tanaka M. A fluorescent cholesterol analogue for observation of free cholesterol in the plasma membrane of live cells. Anal Biochem 2016; 492:49-55. [DOI: 10.1016/j.ab.2015.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 08/14/2015] [Accepted: 09/03/2015] [Indexed: 01/16/2023]
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36
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Wüstner D, Lund FW, Röhrl C, Stangl H. Potential of BODIPY-cholesterol for analysis of cholesterol transport and diffusion in living cells. Chem Phys Lipids 2016; 194:12-28. [DOI: 10.1016/j.chemphyslip.2015.08.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 08/07/2015] [Accepted: 08/12/2015] [Indexed: 01/04/2023]
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37
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Sezgin E, Can FB, Schneider F, Clausen MP, Galiani S, Stanly TA, Waithe D, Colaco A, Honigmann A, Wüstner D, Platt F, Eggeling C. A comparative study on fluorescent cholesterol analogs as versatile cellular reporters. J Lipid Res 2015; 57:299-309. [PMID: 26701325 DOI: 10.1194/jlr.m065326] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Indexed: 12/12/2022] Open
Abstract
Cholesterol (Chol) is a crucial component of cellular membranes, but knowledge of its intracellular dynamics is scarce. Thus, it is of utmost interest to develop tools for visualization of Chol organization and dynamics in cells and tissues. For this purpose, many studies make use of fluorescently labeled Chol analogs. Unfortunately, the introduction of the label may influence the characteristics of the analog, such as its localization, interaction, and trafficking in cells; hence, it is important to get knowledge of such bias. In this report, we compared different fluorescent lipid analogs for their performance in cellular assays: 1) plasma membrane incorporation, specifically the preference for more ordered membrane environments in phase-separated giant unilamellar vesicles and giant plasma membrane vesicles; 2) cellular trafficking, specifically subcellular localization in Niemann-Pick type C disease cells; and 3) applicability in fluorescence correlation spectroscopy (FCS)-based and super-resolution stimulated emission depletion-FCS-based measurements of membrane diffusion dynamics. The analogs exhibited strong differences, with some indicating positive performance in the membrane-based experiments and others in the intracellular trafficking assay. However, none showed positive performance in all assays. Our results constitute a concise guide for the careful use of fluorescent Chol analogs in visualizing cellular Chol dynamics.
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Affiliation(s)
- Erdinc Sezgin
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, OX39DS Oxford, United Kingdom
| | - Fatma Betul Can
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, OX39DS Oxford, United Kingdom
| | - Falk Schneider
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, OX39DS Oxford, United Kingdom
| | - Mathias P Clausen
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, OX39DS Oxford, United Kingdom MEMPHYS-Center for Biomembrane Physics, Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, 5230 Odense M, Denmark
| | - Silvia Galiani
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, OX39DS Oxford, United Kingdom
| | - Tess A Stanly
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, OX39DS Oxford, United Kingdom
| | - Dominic Waithe
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, OX39DS Oxford, United Kingdom
| | - Alexandria Colaco
- Department of Pharmacology, University of Oxford, OX13QT Oxford, United Kingdom
| | - Alf Honigmann
- Max Planck Institute of Cell Biology and Genetics, 01307 Dresden, Germany
| | - Daniel Wüstner
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Frances Platt
- Department of Pharmacology, University of Oxford, OX13QT Oxford, United Kingdom
| | - Christian Eggeling
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, OX39DS Oxford, United Kingdom
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38
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Karilainen T, Vuorela T, Vattulainen I. How Well Does BODIPY-Cholesteryl Ester Mimic Unlabeled Cholesteryl Esters in High Density Lipoprotein Particles? J Phys Chem B 2015; 119:15848-56. [DOI: 10.1021/acs.jpcb.5b10188] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Topi Karilainen
- Department
of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere, Finland
| | - Timo Vuorela
- Department
of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere, Finland
| | - Ilpo Vattulainen
- Department
of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere, Finland
- MEMPHYS-Center
for Biomembrane Physics, University of Southern Denmark, Odense, Denmark
- Department
of Physics, University of Helsinki, P.O. Box 43, FI-00014 Helsinki, Finland
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39
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Venkatesan GA, Lee J, Farimani AB, Heiranian M, Collier CP, Aluru NR, Sarles SA. Adsorption Kinetics Dictate Monolayer Self-Assembly for Both Lipid-In and Lipid-Out Approaches to Droplet Interface Bilayer Formation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:12883-12893. [PMID: 26556227 DOI: 10.1021/acs.langmuir.5b02293] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The droplet interface bilayer (DIB)--a method to assemble planar lipid bilayer membranes between lipid-coated aqueous droplets--has gained popularity among researchers in many fields. Well-packed lipid monolayer on aqueous droplet-oil interfaces is a prerequisite for successfully assembling DIBs. Such monolayers can be achieved by two different techniques: "lipid-in", in which phospholipids in the form of liposomes are placed in water, and "lipid-out", in which phospholipids are placed in oil as inverse micelles. While both approaches are capable of monolayer assembly needed for bilayer formation, droplet pairs assembled with these two techniques require significantly different incubation periods and exhibit different success rates for bilayer formation. In this study, we combine experimental interfacial tension measurements with molecular dynamics simulations of phospholipids (DPhPC and DOPC) assembled from water and oil origins to understand the differences in kinetics of monolayer formation. With the results from simulations and by using a simplified model to analyze dynamic interfacial tensions, we conclude that, at high lipid concentrations common to DIBs, monolayer formation is simple adsorption controlled for lipid-in technique, whereas it is predominantly adsorption-barrier controlled for the lipid-out technique due to the interaction of interface-bound lipids with lipid structures in the subsurface. The adsorption barrier established in lipid-out technique leads to a prolonged incubation time and lower bilayer formation success rate, proving a good correlation between interfacial tension measurements and bilayer formation. We also clarify that advective flow expedites monolayer formation and improves bilayer formation success rate by disrupting lipid structures, rather than enhancing diffusion, in the subsurface and at the interface for lipid-out technique. Additionally, electrical properties of DIBs formed with varying lipid placement and type are characterized.
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Affiliation(s)
- Guru A Venkatesan
- Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - Joonho Lee
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Amir Barati Farimani
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Mohammad Heiranian
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - C Patrick Collier
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Narayana R Aluru
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Stephen A Sarles
- Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee , Knoxville, Tennessee 37996, United States
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40
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Carreira AC, Ventura AE, Varela AR, Silva LC. Tackling the biophysical properties of sphingolipids to decipher their biological roles. Biol Chem 2015; 396:597-609. [DOI: 10.1515/hsz-2014-0283] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 01/01/2015] [Indexed: 11/15/2022]
Abstract
Abstract
From the most simple sphingoid bases to their complex glycosylated derivatives, several sphingolipid species were shown to have a role in fundamental cellular events and/or disease. Increasing evidence places lipid-lipid interactions and membrane structural alterations as central mechanisms underlying the action of these lipids. Understanding how these molecules exert their biological roles by studying their impact in the physical properties and organization of membranes is currently one of the main challenges in sphingolipid research. Herein, we review the progress in the state-of-the-art on the biophysical properties of sphingolipid-containing membranes, focusing on sphingosine, ceramides, and glycosphingolipids.
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41
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Carravilla P, Nieva JL, Goñi FM, Requejo-Isidro J, Huarte N. Two-photon Laurdan studies of the ternary lipid mixture DOPC:SM:cholesterol reveal a single liquid phase at sphingomyelin:cholesterol ratios lower than 1. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:2808-2817. [PMID: 25658036 DOI: 10.1021/la504251u] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The ternary lipid mixture DOPC:eggSM:cholesterol in excess water has been studied in the form of giant unilamellar vesicles using two-photon fluorescence microscopy. Previous publications based on single-photon fluorescence microscopy had reported heterogeneous phase behavior (phase coexistence) in the region of the triangular phase diagram corresponding to SM:cholesterol molar ratios <1. We have examined this region by two-photon microscopy of Laurdan-labeled mixtures and have found that, under our conditions, only a single liquid phase exists. We have shown that macroscopic phase separation in the above region can be artifactually induced by one-photon excitation of the fluorescent probes and ensuing photooxidation and is prevented using two-photon excitation. The main effect of increasing the concentration of cholesterol in mixtures containing 30 mol % SM was to increase the rigidity of the disordered domains. Increasing the concentration of SM in mixtures containing 20 mol % cholesterol gradually augmented the rigidity of the ordered domains, while the disordered domains reached minimal order at a SM:cholesterol 2.25:1 molar ratio, which then increased again. Moreover, the detailed measurement of Laurdan generalized polarization across the whole phase diagram allowed the representation, for both the single- and two-phase regions, of the gradual variation of membrane lateral packing along the diagram, which we found to be governed largely by SM:cholesterol interactions.
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Affiliation(s)
- Pablo Carravilla
- Unidad de Biofísica (CSIC, UPV/EHU), Barrio de Sarriena s/n, 48490 Leioa, Spain
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42
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DeWitt BN, Dunn RC. Interaction of cholesterol in ternary lipid mixtures investigated using single-molecule fluorescence. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:995-1004. [PMID: 25531175 DOI: 10.1021/la503797w] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Fluorescence measurements of the sterol analog 23-(dipyrrometheneboron difluoride)-24-norcholesterol (BODIPY-cholesterol) are used to compare the effects of cholesterol (Chol) in monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC)/1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/Chol and chicken egg sphingomyelin (SM)/DOPC/Chol. Monolayers are formed using the Langmuir-Blodgett technique and compared at surface pressures of 8 and 30 mN/m. In particular, these ternary lipid mixtures are compared using both ensemble and single-molecule fluorescence measurements of BODIPY-cholesterol. In mixed monolayers incorporating 0.10 mol % BODIPY-cholesterol, fluorescence microscopy measurements as a function of cholesterol added reveal similar trends in monolayer phase structure for both DPPC/DOPC/Chol and SM/DOPC/Chol films. With a probe concentration reduced to ∼10(-8) mol % BODIPY-cholesterol, single-molecule fluorescence measurements using defocused polarized total internal reflection microscopy are used to characterize the orientations of BODIPY-cholesterol in the monolayers. Population histograms of the BODIPY emission dipole tilt angle away from the membrane normal reveal distinct insertion geometries with a preferred angle observed near 78°. The measured angles and populations are relatively insensitive to added cholesterol and changes in surface pressure for monolayers of SM/DOPC/Chol. For monolayers of DPPC/DOPC/Chol, however, the single-molecule measurements reveal significant changes in the BODIPY-cholesterol insertion geometry when the surface pressure is increased to 30 mN/m. These changes are discussed in terms of a squeeze-out mechanism for BODIPY-cholesterol in these monolayers and provide insight into the partitioning and arrangement of BODIPY-cholesterol in ternary lipid mixtures.
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Affiliation(s)
- Brittany N DeWitt
- Ralph N. Adams Institute for Bioanalytical Chemistry, University of Kansas , 2030 Becker Drive, Lawrence, Kansas 66047, United States
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43
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Grosjean K, Mongrand S, Beney L, Simon-Plas F, Gerbeau-Pissot P. Differential effect of plant lipids on membrane organization: specificities of phytosphingolipids and phytosterols. J Biol Chem 2015; 290:5810-25. [PMID: 25575593 DOI: 10.1074/jbc.m114.598805] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The high diversity of the plant lipid mixture raises the question of their respective involvement in the definition of membrane organization. This is particularly the case for plant plasma membrane, which is enriched in specific lipids, such as free and conjugated forms of phytosterols and typical phytosphingolipids, such as glycosylinositolphosphoceramides. This question was here addressed extensively by characterizing the order level of membrane from vesicles prepared using various plant lipid mixtures and labeled with an environment-sensitive probe. Fluorescence spectroscopy experiments showed that among major phytosterols, campesterol exhibits a stronger ability than β-sitosterol and stigmasterol to order model membranes. Multispectral confocal microscopy, allowing spatial analysis of membrane organization, demonstrated accordingly the strong ability of campesterol to promote ordered domain formation and to organize their spatial distribution at the membrane surface. Conjugated sterol forms, alone and in synergy with free sterols, exhibit a striking ability to order membrane. Plant sphingolipids, particularly glycosylinositolphosphoceramides, enhanced the sterol-induced ordering effect, emphasizing the formation and increasing the size of sterol-dependent ordered domains. Altogether, our results support a differential involvement of free and conjugated phytosterols in the formation of ordered domains and suggest that the diversity of plant lipids, allowing various local combinations of lipid species, could be a major contributor to membrane organization in particular through the formation of sphingolipid-sterol interacting domains.
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Affiliation(s)
- Kevin Grosjean
- From UMR1347 Agroécologie, ERL 6300 CNRS, Université de Bourgogne, 17 Rue Sully, BP 86510, 21065 Dijon Cedex, France
| | - Sébastien Mongrand
- the Laboratoire de Biogenèse Membranaire (LBM), CNRS, UMR 5200, F-33000 Villenave d'Ornon, France, the Laboratoire de Biogenèse Membranaire (LBM), Université de Bordeaux, UMR 5200, F-33000 Villenave d'Ornon, France
| | - Laurent Beney
- the Laboratoire Procédés Alimentaires et Microbiologiques, AgroSup Dijon, F-21000 Dijon, France, and
| | - Françoise Simon-Plas
- ERL 6300 CNRS, INRA, UMR1347 Agroécologie, 17 Rue Sully, BP 86510, 21065 Dijon Cedex, France
| | - Patricia Gerbeau-Pissot
- From UMR1347 Agroécologie, ERL 6300 CNRS, Université de Bourgogne, 17 Rue Sully, BP 86510, 21065 Dijon Cedex, France,
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44
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Demchenko AP, Duportail G, Oncul S, Klymchenko AS, Mély Y. Introduction to fluorescence probing of biological membranes. Methods Mol Biol 2015; 1232:19-43. [PMID: 25331125 DOI: 10.1007/978-1-4939-1752-5_3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Fluorescence is one of the most powerful and commonly used tools in biophysical studies of biomembrane structure and dynamics that can be applied on different levels, from lipid monolayers and bilayers to living cells, tissues, and whole animals. Successful application of this method relies on proper design of fluorescence probes with optimized photophysical properties. These probes are efficient for studying the microscopic analogs of viscosity, polarity, and hydration, as well as the molecular order, environment relaxation, and electrostatic potentials at the sites of their location. Being smaller than the membrane width they can sense the gradients of these parameters across the membrane. We present examples of novel dyes that achieve increased spatial resolution and information content of the probe responses. In this respect, multiparametric environment-sensitive probes feature considerable promise.
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Affiliation(s)
- Alexander P Demchenko
- Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kiev, 01030, Ukraine,
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Liu Z, Thacker SG, Fernandez-Castillejo S, Neufeld EB, Remaley AT, Bittman R. Synthesis of cholesterol analogues bearing BODIPY fluorophores by Suzuki or Liebeskind-Srogl cross-coupling and evaluation of their potential for visualization of cholesterol pools. Chembiochem 2014; 15:2087-96. [PMID: 25154602 DOI: 10.1002/cbic.201402042] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Indexed: 11/11/2022]
Abstract
We report a synthetic route to BODIPY-cholesterol conjugates in which the key steps were Suzuki or Liebeskind-Srogl cross-coupling of cholesterol phenyl moieties with structurally diverse BODIPY scaffolds. All conjugates feature single-bonded and hydrophobic linkages between the fluorophore and sterol that are devoid of heteroatoms. Using HeLa cells, we show that these BODIPY-cholesterol analogues can be used simultaneously with the parent BODIPY-cholesterol for cell imaging and flow cytometry. The BODIPY-cholesterol analogues exhibit similar cellular localization in HeLa cells and show similar cholesterol efflux properties from THP-1 cells to HDL acceptors. These results demonstrate that the red-shifted BODIPY-cholesterol analogues behave in a manner similar to unlabeled cholesterol and are useful probes for simultaneous visualization of intracellular cholesterol pools and for monitoring cholesterol efflux from cells to extracellular acceptors.
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Affiliation(s)
- Zheng Liu
- Department of Chemistry and Biochemistry, Queens College of The City University of New York, Flushing, NY 11367 (USA)
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46
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Ngo AT, Jakubek ZJ, Lu Z, Joós B, Morris CE, Johnston LJ. Membrane order parameters for interdigitated lipid bilayers measured via polarized total-internal-reflection fluorescence microscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2861-9. [PMID: 25073072 DOI: 10.1016/j.bbamem.2014.07.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 07/03/2014] [Accepted: 07/21/2014] [Indexed: 12/25/2022]
Abstract
Incorporating ethanol in lipid membranes leads to changes in bilayer structure, including the formation of an interdigitated phase. We have used polarized total-internal-reflection fluorescence microscopy (pTIRFM) to measure the order parameter for Texas Red DHPE incorporated in the ethanol-induced interdigitated phase (LβI) formed from ternary lipid mixtures comprising dioleoylphosphatidylcholine, cholesterol and egg sphingomyelin or dipalmitoylphosphatidylcholine. These lipid mixtures have 3 co-existing phases in the presence of ethanol: liquid-ordered, liquid-disordered and LβI. pTIRFM using Texas Red DHPE shows a reversal in fluorescence contrast between the LβI phase and the surrounding disordered phase with changes in the polarization angle. The contrast reversal is due to changes in the orientation of the dye, and provides a rapid method to identify the LβI phase. The measured order parameters for the LβI phase are consistent with a highly ordered membrane environment, similar to a gel phase. An acyl-chain labeled BODIPY-FL-PC was also tested for pTIRFM studies of ethanol-treated bilayers; however, this probe is less useful since the order parameters of the interdigitated phase are consistent with orientations that are close to random, either due to local membrane disorder or to a mixture of extended and looping conformations in which the fluorophore is localized in the polar headgroup region of the bilayer. In summary, we demonstrate that order parameter measurements via pTIRFM using Texas Red-DHPE can rapidly identify the interdigitated phase in supported bilayers. We anticipate that this technique will aid further research in the effects of alcohols and other additives on membranes.
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Affiliation(s)
- An T Ngo
- Measurement Science and Standards, National Research Council Canada, Ottawa, ON K1A 0R6, Canada; Department of Physics, University of Ottawa Ottawa, ON K1N 6N5, Canada
| | - Zygmunt J Jakubek
- Measurement Science and Standards, National Research Council Canada, Ottawa, ON K1A 0R6, Canada
| | - Zhengfang Lu
- Measurement Science and Standards, National Research Council Canada, Ottawa, ON K1A 0R6, Canada
| | - Béla Joós
- Department of Physics, University of Ottawa Ottawa, ON K1N 6N5, Canada
| | | | - Linda J Johnston
- Measurement Science and Standards, National Research Council Canada, Ottawa, ON K1A 0R6, Canada.
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Wüstner D, Christensen T, Solanko LM, Sage D. Photobleaching kinetics and time-integrated emission of fluorescent probes in cellular membranes. Molecules 2014; 19:11096-130. [PMID: 25076144 PMCID: PMC6271172 DOI: 10.3390/molecules190811096] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 07/04/2014] [Accepted: 07/10/2014] [Indexed: 12/02/2022] Open
Abstract
Since the pioneering work of Hirschfeld, it is known that time-integrated emission (TiEm) of a fluorophore is independent of fluorescence quantum yield and illumination intensity. Practical implementation of this important result for determining exact probe distribution in living cells is often hampered by the presence of autofluorescence. Using kinetic modelling of photobleaching combined with pixel-wise bleach rate fitting of decay models with an updated plugin to the ImageJ program, it is shown that the TiEm of a fluorophore in living cells can be determined exactly from the product of bleaching amplitude and time constant. This applies to mono-exponential bleaching from the first excited singlet and/or triplet state and to multi-exponential combinations of such processes. The TiEm can be used to correct for illumination shading and background autofluorescence without the need for fluorescent test layers or separate imaging of non-stained cells. We apply the method to simulated images and to images of cells, whose membranes were labelled with fluorescent sterols and sphingolipids. Our bleaching model can be extended to include a probability density function (PDF) of intrinsic bleach rate constants with a memory kernel. This approach results in a time-dependent bleach rate coefficient and is exemplified for fluorescent sterols in restricted intracellular environments, like lipid droplets. We show that for small deviations from the classical exponential bleaching, the TiEm of decay functions with rate coefficients remains largely independent of fluorescence lifetime and illumination, and thereby represents a faithful measure of probe distribution.
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Affiliation(s)
- Daniel Wüstner
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.
| | - Tanja Christensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.
| | - Lukasz M Solanko
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.
| | - Daniel Sage
- Biomedical Imaging Group, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
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Bacia K, Haustein E, Schwille P. Fluorescence correlation spectroscopy: principles and applications. Cold Spring Harb Protoc 2014; 2014:709-25. [PMID: 24987147 DOI: 10.1101/pdb.top081802] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Fluorescence correlation spectroscopy (FCS) is used to study the movements and the interactions of biomolecules at extremely dilute concentrations, yielding results with good spatial and temporal resolutions. Using a number of technical developments, FCS has become a versatile technique that can be used to study a variety of sample types and can be advantageously combined with other methods. Unlike other fluorescence-based techniques, the analysis of FCS data is not based on the average intensity of the fluorescence emission but examines the minute intensity fluctuations caused by spontaneous deviations from the mean at thermal equilibrium. These fluctuations can result from variations in local concentrations owing to molecular mobility or from characteristic intermolecular or intramolecular reactions of fluorescently labeled biomolecules present at low concentrations. Here, we provide a basic introduction to FCS, including its technical development and theoretical basis, experimental setup of an FCS system, adjustment of a setup, data acquisition, and analysis of FCS measurements. Finally, the application of FCS to the study of lipid bilayer membranes and to living cells is discussed.
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Solanko LM, Honigmann A, Midtiby HS, Lund FW, Brewer JR, Dekaris V, Bittman R, Eggeling C, Wüstner D. Membrane orientation and lateral diffusion of BODIPY-cholesterol as a function of probe structure. Biophys J 2014; 105:2082-92. [PMID: 24209853 DOI: 10.1016/j.bpj.2013.09.031] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 08/26/2013] [Accepted: 09/16/2013] [Indexed: 11/29/2022] Open
Abstract
Cholesterol tagged with the BODIPY fluorophore via the central difluoroboron moiety of the dye (B-Chol) is a promising probe for studying intracellular cholesterol dynamics. We synthesized a new BODIPY-cholesterol probe (B-P-Chol) with the fluorophore attached via one of its pyrrole rings to carbon-24 of cholesterol (B-P-Chol). Using two-photon fluorescence polarimetry in giant unilamellar vesicles and in the plasma membrane (PM) of living intact and actin-disrupted cells, we show that the BODIPY-groups in B-Chol and B-P-Chol are oriented perpendicular and almost parallel to the bilayer normal, respectively. B-Chol is in all three membrane systems much stronger oriented than B-P-Chol. Interestingly, we found that the lateral diffusion in the PM was two times slower for B-Chol than for B-P-Chol, although we found no difference in lateral diffusion in model membranes. Stimulated emission depletion microscopy, performed for the first time, to our knowledge, with fluorescent sterols, revealed that the difference in lateral diffusion of the BODIPY-cholesterol probes was not caused by anomalous subdiffusion, because diffusion of both analogs in the PM was free but not hindered. Our combined measurements show that the position and orientation of the BODIPY moiety in cholesterol analogs have a severe influence on lateral diffusion specifically in the PM of living cells.
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Affiliation(s)
- Lukasz M Solanko
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
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50
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Hiramoto-Yamaki N, Tanaka KAK, Suzuki KGN, Hirosawa KM, Miyahara MSH, Kalay Z, Tanaka K, Kasai RS, Kusumi A, Fujiwara TK. Ultrafast diffusion of a fluorescent cholesterol analog in compartmentalized plasma membranes. Traffic 2014; 15:583-612. [PMID: 24506328 PMCID: PMC4265843 DOI: 10.1111/tra.12163] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 02/05/2014] [Accepted: 02/07/2014] [Indexed: 01/20/2023]
Abstract
Cholesterol distribution and dynamics in the plasma membrane (PM) are poorly understood. The recent development of Bodipy488-conjugated cholesterol molecule (Bdp-Chol) allowed us to study cholesterol behavior in the PM, using single fluorescent-molecule imaging. Surprisingly, in the intact PM, Bdp-Chol diffused at the fastest rate ever found for any molecules in the PM, with a median diffusion coefficient (D) of 3.4 µm2/second, which was ∼10 times greater than that of non-raft phospholipid molecules (0.33 µm2/second), despite Bdp-Chol's probable association with raft domains. Furthermore, Bdp-Chol exhibited no sign of entrapment in time scales longer than 0.5 milliseconds. In the blebbed PM, where actin filaments were largely depleted, Bdp-Chol and Cy3-conjugated dioleoylphosphatidylethanolamine (Cy3-DOPE) diffused at comparable Ds (medians = 5.8 and 6.2 µm2/second, respectively), indicating that the actin-based membrane skeleton reduces the D of Bdp-Chol only by a factor of ∼2 from that in the blebbed PM, whereas it reduces the D of Cy3-DOPE by a factor of ∼20. These results are consistent with the previously proposed model, in which the PM is compartmentalized by the actin-based membrane-skeleton fence and its associated transmembrane picket proteins for the macroscopic diffusion of all of the membrane molecules, and suggest that the probability of Bdp-Chol passing through the compartment boundaries, once it enters the boundary, is ∼10× greater than that of Cy3-DOPE. Since the compartment sizes are greater than those of the putative raft domains, we conclude that raft domains coexist with membrane-skeleton-induced compartments and are contained within them.
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Affiliation(s)
- Nao Hiramoto-Yamaki
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS) and Institute for Frontier Medical Sciences, Kyoto University, Kyoto, 606-8507, Japan
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