1
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Wang L, Dresel MJ, Robinson M, Izgu EC. Protocol for building synthetic protocell membranes that sense redox using synthetic phospholipids and natural lipids. STAR Protoc 2024; 5:103169. [PMID: 38970793 DOI: 10.1016/j.xpro.2024.103169] [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: 04/23/2024] [Revised: 05/16/2024] [Accepted: 06/13/2024] [Indexed: 07/08/2024] Open
Abstract
Sensing is a critical function of artificial cells; however, this is challenging to realize using bottom-up approaches. Here, we present a protocol for building protocell membranes that sense cues important for redox biochemistry and signaling by combining synthetic phospholipids and natural lipids. We detail procedures for building giant unilamellar vesicles as protocell models that fluoresce in response to the biologically significant redox agents peroxynitrite, hydrogen peroxide, and hydrogen sulfide. For complete details on the use and execution of this protocol, please refer to (i) Gutierrez and Aggarwal et al.1 as well as (ii) Erguven and Wang et al.2.
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Affiliation(s)
- Liming Wang
- Department of Chemistry and Chemical Biology, Rutgers University-New Brunswick, Piscataway, NJ 08854, USA
| | - Mark J Dresel
- Department of Chemistry and Chemical Biology, Rutgers University-New Brunswick, Piscataway, NJ 08854, USA
| | - Monique Robinson
- Department of Mechanical and Aerospace Engineering, Rutgers University-New Brunswick, Piscataway, NJ 08854, USA
| | - Enver Cagri Izgu
- Department of Chemistry and Chemical Biology, Rutgers University-New Brunswick, Piscataway, NJ 08854, USA; Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ 08901, USA; Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University-New Brunswick, New Brunswick, NJ 08901, USA.
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2
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Weakly HMJ, Keller SL. Coupling liquid phases in 3D condensates and 2D membranes: Successes, challenges, and tools. Biophys J 2024; 123:1329-1341. [PMID: 38160256 PMCID: PMC11163299 DOI: 10.1016/j.bpj.2023.12.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 12/05/2023] [Accepted: 12/26/2023] [Indexed: 01/03/2024] Open
Abstract
This review describes the major experimental challenges researchers meet when attempting to couple phase separation between membranes and condensates. Although it is well known that phase separation in a 2D membrane could affect molecules capable of forming a 3D condensate (and vice versa), few researchers have quantified the effects to date. The scarcity of these measurements is not due to a lack of intense interest or effort in the field. Rather, it reflects significant experimental challenges in manipulating coupled membranes and condensates to yield quantitative values. These challenges transcend many molecular details, which means they impact a wide range of systems. This review highlights recent exciting successes in the field, and it lays out a comprehensive list of tools that address potential pitfalls for researchers who are considering coupling membranes with condensates.
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Affiliation(s)
- Heidi M J Weakly
- Department of Chemistry, University of Washington - Seattle, Seattle, Washington
| | - Sarah L Keller
- Department of Chemistry, University of Washington - Seattle, Seattle, Washington.
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3
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Dwivedi A, Mazumder A, Pullmannová P, Paraskevopoulou A, Opálka L, Kováčik A, Macháček M, Jančálková P, Svačinová P, Peterlik H, Maixner J, Vávrová K. Lipid Monolayer on Cell Surface Protein Templates Functional Extracellular Lipid Assembly. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2307793. [PMID: 38243890 DOI: 10.1002/smll.202307793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 12/18/2023] [Indexed: 01/22/2024]
Abstract
When the ancestors of men moved from aquatic habitats to the drylands, their evolutionary strategy to restrict water loss is to seal the skin surface with lipids. It is unknown how these rigid ceramide-dominated lipids with densely packed chains squeeze through narrow extracellular spaces and how they assemble into their complex multilamellar architecture. Here it is shown that the human corneocyte lipid envelope, a monolayer of ultralong covalently bound lipids on the cell surface protein, templates the functional barrier assembly by partly fluidizing and rearranging the free extracellular lipids in its vicinity during the sculpting of a functional skin lipid barrier. The lipid envelope also maintains the fluidity of the extracellular lipids during mechanical stress. This local lipid fluidization does not compromise the permeability barrier. The results provide new testable hypotheses about epidermal homeostasis and the pathophysiology underlying diseases with impaired lipid binding to corneocytes, such as congenital ichthyosis. In a broader sense, this lipoprotein-mediated fluidization of rigid (sphingo)lipid patches may also be relevant to lipid rafts and cellular signaling events and inspire new functional materials.
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Affiliation(s)
- Anupma Dwivedi
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Anisha Mazumder
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Petra Pullmannová
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Anna Paraskevopoulou
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Lukáš Opálka
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Andrej Kováčik
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Miloslav Macháček
- Department of Biochemical Sciences, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Pavla Jančálková
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Petra Svačinová
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
| | - Herwig Peterlik
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, Vienna, 1090, Austria
| | - Jaroslav Maixner
- Faculty of Chemical Technology, University of Chemistry and Technology Prague, Technická 5, Prague, 16628, Czech Republic
| | - Kateřina Vávrová
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové, 50005, Czech Republic
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4
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Tutkus M, Lundgaard CV, Veshaguri S, Tønnesen A, Hatzakis N, Rasmussen SGF, Stamou D. Probing Activation and Conformational Dynamics of the Vesicle-Reconstituted β 2 Adrenergic Receptor at the Single-Molecule Level. J Phys Chem B 2024; 128:2124-2133. [PMID: 38391238 PMCID: PMC10926102 DOI: 10.1021/acs.jpcb.3c08349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
G-protein-coupled receptors (GPCRs) are structurally flexible membrane proteins that mediate a host of physiological responses to extracellular ligands like hormones and neurotransmitters. Fine features of their dynamic structural behavior are hypothesized to encode the functional plasticity seen in GPCR activity, where ligands with different efficacies can direct the same receptor toward different signaling phenotypes. Although the number of GPCR crystal structures is increasing, the receptors are characterized by complex and poorly understood conformational landscapes. Therefore, we employed a fluorescence microscopy assay to monitor conformational dynamics of single β2 adrenergic receptors (β2ARs). To increase the biological relevance of our findings, we decided not to reconstitute the receptor in detergent micelles but rather lipid membranes as proteoliposomes. The conformational dynamics were monitored by changes in the intensity of an environmentally sensitive boron-dipyrromethene (BODIPY 493/503) fluorophore conjugated to an endogenous cysteine (located at the cytoplasmic end of the sixth transmembrane helix of the receptor). Using total internal reflection fluorescence microscopy (TIRFM) and a single small unilamellar liposome assay that we previously developed, we followed the real-time dynamic properties of hundreds of single β2ARs reconstituted in a native-like environment─lipid membranes. Our results showed that β2AR-BODIPY fluctuates between several states of different intensity on a time scale of seconds, compared to BODIPY-lipid conjugates that show almost entirely stable fluorescence emission in the absence and presence of the full agonist BI-167107. Agonist stimulation changes the β2AR dynamics, increasing the population of states with higher intensities and prolonging their durations, consistent with bulk experiments. The transition density plot demonstrates that β2AR-BODIPY, in the absence of the full agonist, interconverts between states of low and moderate intensity, while the full agonist renders transitions between moderate and high-intensity states more probable. This redistribution is consistent with a mechanism of conformational selection and is a promising first step toward characterizing the conformational dynamics of GPCRs embedded in a lipid bilayer.
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Affiliation(s)
- Marijonas Tutkus
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio Ave. 7, LT-10257 Vilnius, Lithuania
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Saulėtekio Ave. 3, LT-10257 Vilnius, Lithuania
| | - Christian V Lundgaard
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Salome Veshaguri
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Asger Tønnesen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Nikos Hatzakis
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
- Department of Chemistry and Nanoscience Center, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Søren G F Rasmussen
- Department of Neuroscience and Pharmacology, Panum, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Dimitrios Stamou
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
- Center for Geometrically Engineered Cellular Systems, Universitetsparken 5, DK-2100 Copenhagen, Denmark
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5
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Wang R, Shi X, Li C. Insights into the Surface Binding and Structural Interference of Polyphenols with the Membrane Raft Domains in Relation to Their Distinctive Ability to Inhibit Preadipocyte Differentiation in 3T3-L1 Cells. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:19845-19855. [PMID: 38050784 DOI: 10.1021/acs.jafc.3c06747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2023]
Abstract
Polyphenols with different structures have shown distinct variations in their ability to inhibit the differentiation of 3T3-L1 preadipocytes. However, the underlying mechanisms for these differences remain unclear. In the present study, the surface binding of polyphenols to different membrane domains was explored using coarse-grained molecular dynamics simulation (CG-MDs). Subsequently, this surface binding was confirmed in the liposome system by microscale thermophoresis. Additionally, the interference of polyphenols on the membrane raft's structure was studied through atomic force microscopy and high-content screening fluorescence microscopy. The results indicated that polyphenols with a differentiation-inhibitory ability, such as epicatechin-3-gallate (ECG) and epicatechin-3-gallate-(4β → 8, 2β → O → 7)-epicatechin-3-gallate (A-type ECG dimer), exhibited strong binding to ordered domains enriched in sphingolipids and cholesterol. This binding led to the structural disruption of membrane rafts by altering their size and shape, with the binding constant of 3.8 μM for ECG and 0.3 μM for A-type ECG dimer, respectively. In contrast, epicatechin (EC) with little differentiation-inhibitory ability had no effects on membrane rafts, and its binding constant with the ordered domain was 380.6 μM. Overall, the surface binding of polyphenols to ordered domains and the resulting disruption of membrane rafts structure might be a fundamental mechanism by which polyphenols inhibited the differentiation of 3T3-L1 preadipocytes.
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Affiliation(s)
- Ruifeng Wang
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Xin Shi
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Chunmei Li
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- Key Laboratory of Environment Correlative Food Science, Ministry of Education, Wuhan, Hubei 430070, China
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6
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Nair KS, Bajaj H. Advances in giant unilamellar vesicle preparation techniques and applications. Adv Colloid Interface Sci 2023; 318:102935. [PMID: 37320960 DOI: 10.1016/j.cis.2023.102935] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 05/23/2023] [Accepted: 06/05/2023] [Indexed: 06/17/2023]
Abstract
Giant unilamellar vesicles (GUVs) are versatile and promising cell-sized bio-membrane mimetic platforms. Their applications range from understanding and quantifying membrane biophysical processes to acting as elementary blocks in the bottom-up assembly of synthetic cells. Definite properties and requisite goals in GUVs are dictated by the preparation techniques critical to the success of their applications. Here, we review key advances in giant unilamellar vesicle preparation techniques and discuss their formation mechanisms. Developments in lipid hydration and emulsion techniques for GUV preparation are described. Novel microfluidic-based techniques involving lipid or surfactant-stabilized emulsions are outlined. GUV immobilization strategies are summarized, including gravity-based settling, covalent linking, and immobilization by microfluidic, electric, and magnetic barriers. Moreover, some of the key applications of GUVs as biomimetic and synthetic cell platforms during the last decade have been identified. Membrane interface processes like phase separation, membrane protein reconstitution, and membrane bending have been deciphered using GUVs. In addition, vesicles are also employed as building blocks to construct synthetic cells with defined cell-like functions comprising compartments, metabolic reactors, and abilities to grow and divide. We critically discuss the pros and cons of preparation technologies and the properties they confer to the GUVs and identify potential techniques for dedicated applications.
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Affiliation(s)
- Karthika S Nair
- Microbial Processes and Technology Division, CSIR- National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695019, Kerala, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad 201002, India
| | - Harsha Bajaj
- Microbial Processes and Technology Division, CSIR- National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695019, Kerala, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad 201002, India.
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7
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Dolder N, Müller P, von Ballmoos C. Experimental platform for the functional investigation of membrane proteins in giant unilamellar vesicles. SOFT MATTER 2022; 18:5877-5893. [PMID: 35916307 PMCID: PMC9364335 DOI: 10.1039/d2sm00551d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Giant unilamellar vesicles (GUVs) are micrometer-sized model membrane systems that can be viewed directly under the microscope. They serve as scaffolds for the bottom-up creation of synthetic cells, targeted drug delivery and have been widely used to study membrane related phenomena in vitro. GUVs are also of interest for the functional investigation of membrane proteins that carry out many key cellular functions. A major hurdle to a wider application of GUVs in this field is the diversity of existing protocols that are optimized for individual proteins. Here, we compare PVA assisted and electroformation techniques for GUV formation under physiologically relevant conditions, and analyze the effect of immobilization on vesicle structure and membrane tightness towards small substrates and protons. There, differences in terms of yield, size, and leakage of GUVs produced by PVA assisted swelling and electroformation were found, dependent on salt and buffer composition. Using fusion of oppositely charged membranes to reconstitute a model membrane protein, we find that empty vesicles and proteoliposomes show similar fusion behavior, which allows for a rapid estimation of protein incorporation using fluorescent lipids.
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Affiliation(s)
- Nicolas Dolder
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.
| | - Philipp Müller
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.
| | - Christoph von Ballmoos
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.
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8
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Impact of Ca2+-Induced PI(4,5)P2 Clusters on PH-YFP Organization and Protein-Protein Interactions. Biomolecules 2022; 12:biom12070912. [PMID: 35883468 PMCID: PMC9312469 DOI: 10.3390/biom12070912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/22/2022] [Accepted: 06/27/2022] [Indexed: 11/16/2022] Open
Abstract
Despite its low abundance, phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) is a key modulator of membrane-associated signaling events in eukaryotic cells. Temporal and spatial regulation of PI(4,5)P2 concentration can achieve localized increases in the levels of this lipid, which are crucial for the activation or recruitment of peripheral proteins to the plasma membrane. The recent observation of the dramatic impact of physiological divalent cation concentrations on PI(4,5)P2 clustering, suggests that protein anchoring to the plasma membrane through PI(4,5)P2 is likely not defined solely by a simple (monomeric PI(4,5)P2)/(protein bound PI(4,5)P2) equilibrium, but instead depends on complex protein interactions with PI(4,5)P2 clusters. The insertion of PI(4,5)P2-binding proteins within these clusters can putatively modulate protein–protein interactions in the membrane, but the relevance of such effects is largely unknown. In this work, we characterized the impact of Ca2+ on the organization and protein–protein interactions of PI(4,5)P2-binding proteins. We show that, in giant unilamellar vesicles presenting PI(4,5)P2, the membrane diffusion properties of pleckstrin homology (PH) domains tagged with a yellow fluorescent protein (YFP) are affected by the presence of Ca2+, suggesting direct interactions between the protein and PI(4,5)P2 clusters. Importantly, PH-YFP is found to dimerize in the membrane in the absence of Ca2+. This oligomerization is inhibited in the presence of physiological concentrations of the divalent cation. These results confirm that cation-dependent PI(4,5)P2 clustering promotes interactions between PI(4,5)P2-binding proteins and has the potential to dramatically influence the organization and downstream interactions of PI(4,5)P2-binding proteins in the plasma membrane.
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9
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Zubaite G, Hindley JW, Ces O, Elani Y. Dynamic Reconfiguration of Subcompartment Architectures in Artificial Cells. ACS NANO 2022; 16:9389-9400. [PMID: 35695383 PMCID: PMC9245354 DOI: 10.1021/acsnano.2c02195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 04/27/2022] [Indexed: 06/01/2023]
Abstract
Artificial cells are minimal structures constructed from biomolecular building blocks designed to mimic cellular processes, behaviors, and architectures. One near-ubiquitous feature of cellular life is the spatial organization of internal content. We know from biology that organization of content (including in membrane-bound organelles) is linked to cellular functions and that this feature is dynamic: the presence, location, and degree of compartmentalization changes over time. Vesicle-based artificial cells, however, are not currently able to mimic this fundamental cellular property. Here, we describe an artificial cell design strategy that addresses this technological bottleneck. We create a series of artificial cell architectures which possess multicompartment assemblies localized either on the inner or on the outer surface of the artificial cell membrane. Exploiting liquid-liquid phase separation, we can also engineer spatially segregated regions of condensed subcompartments attached to the cell surface, aligning with coexisting membrane domains. These structures can sense changes in environmental conditions and respond by reversibly transitioning from condensed multicompartment layers on the membrane surface to a dispersed state in the cell lumen, mimicking the dynamic compartmentalization found in biological cells. Likewise, we engineer exosome-like subcompartments that can be released to the environment. We can achieve this by using two types of triggers: chemical (addition of salts) and mechanical (by pulling membrane tethers using optical traps). These approaches allow us to control the compartmentalization state of artificial cells on population and single-cell levels.
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Affiliation(s)
- Greta Zubaite
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London W12
0BZ, United Kingdom
- Department
of Chemical Engineering, Imperial College
London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - James W. Hindley
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London W12
0BZ, United Kingdom
- Institute
of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London W12
0BZ, United Kingdom
- fabriCELL,
Molecular Sciences Research Hub, Imperial
College London, 82 Wood Lane, London W12
0BZ, United Kingdom
| | - Oscar Ces
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London W12
0BZ, United Kingdom
- Institute
of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London W12
0BZ, United Kingdom
- fabriCELL,
Molecular Sciences Research Hub, Imperial
College London, 82 Wood Lane, London W12
0BZ, United Kingdom
| | - Yuval Elani
- fabriCELL,
Molecular Sciences Research Hub, Imperial
College London, 82 Wood Lane, London W12
0BZ, United Kingdom
- Department
of Chemical Engineering, Imperial College
London, Exhibition Road, London SW7 2AZ, United Kingdom
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10
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Acyl-chain saturation regulates the order of phosphatidylinositol 4,5-bisphosphate nanodomains. Commun Chem 2021; 4:164. [PMID: 36697613 PMCID: PMC9814227 DOI: 10.1038/s42004-021-00603-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 11/10/2021] [Indexed: 01/28/2023] Open
Abstract
Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) plays a critical role in the regulation of various plasma membrane processes and signaling pathways in eukaryotes. A significant amount of cellular resources are spent on maintaining the dominant 1-stearoyl-2-arachidonyl PI(4,5)P2 acyl-chain composition, while less abundant and more saturated species become more prevalent in response to specific stimuli, stress or aging. Here, we report the impact of acyl-chain structure on the biophysical properties of cation-induced PI(4,5)P2 nanodomains. PI(4,5)P2 species with increasing levels of acyl-chain saturation cluster in progressively more ordered nanodomains, culminating in the formation of gel-like nanodomains for fully saturated species. The formation of these gel-like domains was largely abrogated in the presence of 1-stearoyl-2-arachidonyl PI(4,5)P2. This is, to the best of our knowledge, the first report of the impact of PI(4,5)P2 acyl-chain composition on cation-dependent nanodomain ordering, and provides important clues to the motives behind the enrichment of PI(4,5)P2 with polyunsaturated acyl-chains. We also show how Ca2+-induced PI(4,5)P2 nanodomains are able to generate local negative curvature, a phenomenon likely to play a role in membrane remodeling events.
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11
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Jennings CS, Rossman JS, Hourihan BA, Marshall RJ, Forgan RS, Blight BA. Immobilising giant unilamellar vesicles with zirconium metal-organic framework anchors. SOFT MATTER 2021; 17:2024-2027. [PMID: 33599656 DOI: 10.1039/d0sm02188a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Lipid bilayer vesicles have provided a window into the function and fundamental properties of cells. However, as is the case for most living and soft matter, vesicles do not remain still. This necessitates some microscopy experiments to include a preparatory immobilisation step. Here, we describe a straightforward method to immobilise giant unilamellar vesicles (GUVs) using zirconium-based metal-organic frameworks (MOFs) and demonstrate that GUVs bound in this way will stay in position on a timescale of minutes to hours.
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Affiliation(s)
- Christopher S Jennings
- Department of Chemistry, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada.
| | - Jeremy S Rossman
- School of Biosciences, University of Kent, Canterbury, CT2 7NH, UK
| | - Braeden A Hourihan
- Department of Chemistry, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada.
| | - Ross J Marshall
- WestCHEM, School of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK
| | - Ross S Forgan
- WestCHEM, School of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK
| | - Barry A Blight
- Department of Chemistry, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada.
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12
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Ventura AE, Santos TCB, Marquês JT, de Almeida RFM, Silva LC. Biophysical Analysis of Lipid Domains by Fluorescence Microscopy. Methods Mol Biol 2021; 2187:223-245. [PMID: 32770510 DOI: 10.1007/978-1-0716-0814-2_13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2023]
Abstract
The study of the structure and dynamics of membrane domains in vivo is a challenging task. However, major advances could be achieved through the application of microscopic and spectroscopic techniques coupled with the use of model membranes, where the relations between lipid composition and the type, amount and properties of the domains present can be quantitatively studied.This chapter provides protocols to study membrane organization and visualize membrane domains by fluorescence microscopy both in artificial membrane and living cell models of Gaucher Disease (GD ). We describe a bottom-up multiprobe methodology, which enables understanding how the specific lipid interactions established by glucosylceramide, the lipid that accumulates in GD , affect the biophysical properties of model and cell membranes, focusing on its ability to influence the formation, properties and organization of lipid raft domains. In this context, we address the preparation of (1) raft-mimicking giant unilamellar vesicles labeled with a combination of fluorophores that allow for the visualization and comprehensive characterization of those membrane domains and (2) human fibroblasts exhibiting GD phenotype to assess the biophysical properties of biological membrane in living cells using fluorescence microscopy.
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Affiliation(s)
- Ana E Ventura
- Research Institute for medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
- CQFM-IN and IBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Tânia C B Santos
- Research Institute for medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
- CQFM-IN and IBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Joaquim T Marquês
- Centro de Química e Bioquímica, Centro de Química Estrutural, DQB, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
| | - Rodrigo F M de Almeida
- Centro de Química e Bioquímica, Centro de Química Estrutural, DQB, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
| | - Liana C Silva
- Research Institute for medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal.
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13
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Ventura A, Varela A, Dingjan T, Santos T, Fedorov A, Futerman A, Prieto M, Silva L. Lipid domain formation and membrane shaping by C24-ceramide. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183400. [DOI: 10.1016/j.bbamem.2020.183400] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 06/05/2020] [Accepted: 06/15/2020] [Indexed: 01/29/2023]
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14
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Liu Z, Cui J, Zhan W. Dipolar Janus liposomes: formation, electrokinetic motion and self-assembly. SOFT MATTER 2020; 16:2177-2184. [PMID: 31998919 DOI: 10.1039/c9sm02254f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Presented herein is the first report on dipolar Janus liposomes-liposomes that contain opposite surface charges decorating the two hemispheres of the same colloidal body. Such heterogeneous organization of surface charge is achieved through cholesterol-modulated lipid phase separation, which sorts anionic/cationic lipids into coexisting liquid-ordered/liquid-disordered domains. We present optimized experimental conditions to produce these liposomes in high yields, based on the gel-assisted hydration of ternary lipid systems consisting of cholesterol, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, and 1,2-dioleoyl-sn-glycero-3-phosphocholine. The size/charge distribution and domain configuration of these liposomes are characterized in detail by confocal fluorescence microscopy, nanosphere binding and zeta potential measurements. Using confocal fluorescence microscopy, we also follow the electrokinetic motion as well as the electrostatic self-assembly of these new dipolar Janus particles.
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Affiliation(s)
- Zening Liu
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA.
| | - Jinyan Cui
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA.
| | - Wei Zhan
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA.
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15
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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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16
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Robinson T, Dittrich PS. Observations of Membrane Domain Reorganization in Mechanically Compressed Artificial Cells. Chembiochem 2019; 20:2666-2673. [DOI: 10.1002/cbic.201900167] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Indexed: 01/01/2023]
Affiliation(s)
- Tom Robinson
- ETH ZurichDepartment of Biosystems Science and Engineering Mattenstrasse 26 4058 Basel Switzerland
- Present address: Department of Theory, Bio-SystemsMax Planck Institute of Colloids and Interfaces Science Park Golm 14424 Potsdam Germany
| | - Petra S. Dittrich
- ETH ZurichDepartment of Biosystems Science and Engineering Mattenstrasse 26 4058 Basel Switzerland
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17
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Robinson T. Microfluidic Handling and Analysis of Giant Vesicles for Use as Artificial Cells: A Review. ACTA ACUST UNITED AC 2019; 3:e1800318. [PMID: 32648705 DOI: 10.1002/adbi.201800318] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 03/22/2019] [Indexed: 01/04/2023]
Abstract
One of the goals of synthetic biology is the bottom-up construction of an artificial cell, the successful realization of which could shed light on how cellular life emerged and could also be a useful tool for studying the function of modern cells. Using liposomes as biomimetic containers is particularly promising because lipid membranes are biocompatible and much of the required machinery can be reconstituted within them. Giant lipid vesicles have been used extensively in other fields such as biophysics and drug discovery, but their use as artificial cells has only recently seen an increase. Despite the prevalence of giant vesicles, many experiments remain challenging or impossible due to their delicate nature compared to biological cells. This review aims to highlight the effectiveness of microfluidic technologies in handling and analyzing giant vesicles. The advantages and disadvantages of different microfluidic approaches and what new insights can be gained from various applications are introduced. Finally, future directions are discussed in which the unique combination of microfluidics and giant lipid vesicles can push forward the bottom-up construction of artificial cells.
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Affiliation(s)
- Tom Robinson
- Department of Theory & Bio-Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, 14424, Germany
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18
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Yandrapalli N, Robinson T. Ultra-high capacity microfluidic trapping of giant vesicles for high-throughput membrane studies. LAB ON A CHIP 2019; 19:626-633. [PMID: 30632596 DOI: 10.1039/c8lc01275j] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Biomimetic systems such as model lipid membranes are vital to many research fields including synthetic biology, drug discovery and membrane biophysics. One of the most commonly used are giant unilamellar vesicles (GUVs) due to their size similarity with biological cells and their ease of production. Typical methods for handling such delicate objects are low-throughput and do not allow solution exchange or long-term observations, all of which limits the experimental options. Herein, we present a new device designed to confine large assemblies of GUVs in microfluidic traps but is still able to perform precise and fast solution exchanges. An optimised design allows efficient filling with as many as 114 GUVs per trap and over 23 000 GUVs per device. This allows high-throughput dataset acquisitions which we demonstrate with two proof-of-concept experiments: (i) end-point measurements of vesicle interior pH and (ii) membrane transport kinetics. Moreover, we show that the design is able to selectively trap sub-populations of specific vesicle sizes and assemble them in different layers. The device can easily be applied to other high-throughput membrane studies and will pave the way for future applications using vesicle assemblies to model cellular tissues or even prototissues.
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Affiliation(s)
- Naresh Yandrapalli
- Department of Theory & Bio-Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany.
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19
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Sarmento MJ, Coutinho A, Fedorov A, Prieto M, Fernandes F. Membrane Order Is a Key Regulator of Divalent Cation-Induced Clustering of PI(3,5)P 2 and PI(4,5)P 2. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:12463-12477. [PMID: 28961003 DOI: 10.1021/acs.langmuir.7b00666] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Although the evidence for the presence of functionally important nanosized phosphorylated phosphoinositide (PIP)-rich domains within cellular membranes has accumulated, very limited information is available regarding the structural determinants for compartmentalization of these phospholipids. Here, we used a combination of fluorescence spectroscopy and microscopy techniques to characterize differences in divalent cation-induced clustering of PI(4,5)P2 and PI(3,5)P2. Through these methodologies we were able to detect differences in divalent cation-induced clustering efficiency and cluster size. Ca2+-induced PI(4,5)P2 clusters are shown to be significantly larger than the ones observed for PI(3,5)P2. Clustering of PI(4,5)P2 is also detected at physiological concentrations of Mg2+, suggesting that in cellular membranes, these molecules are constitutively driven to clustering by the high intracellular concentration of divalent cations. Importantly, it is shown that lipid membrane order is a key factor in the regulation of clustering for both PIP isoforms, with a major impact on cluster sizes. Clustered PI(4,5)P2 and PI(3,5)P2 are observed to present considerably higher affinity for more ordered lipid phases than the monomeric species or than PI(4)P, possibly reflecting a more general tendency of clustered lipids for insertion into ordered domains. These results support a model for the description of the lateral organization of PIPs in cellular membranes, where both divalent cation interaction and membrane order are key modulators defining the lateral organization of these lipids.
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Affiliation(s)
- Maria J Sarmento
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon , 1649-004 Lisbon, Portugal
- J. Heyrovský Inst. Physical Chemistry of the A.S.C.R. v.v.i. , 182 23 Prague, Czech Republic
| | - Ana Coutinho
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon , 1649-004 Lisbon, Portugal
- Departamento de Química e Bioquímica, FCUL, University of Lisbon , 1649-004 Lisbon, Portugal
| | - Aleksander Fedorov
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon , 1649-004 Lisbon, Portugal
| | - Manuel Prieto
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon , 1649-004 Lisbon, Portugal
| | - Fábio Fernandes
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon , 1649-004 Lisbon, Portugal
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa , Campus da Caparica, 2829-516 Caparica, Portugal
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20
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Kubsch B, Robinson T, Steinkühler J, Dimova R. Phase Behavior of Charged Vesicles Under Symmetric and Asymmetric Solution Conditions Monitored with Fluorescence Microscopy. J Vis Exp 2017. [PMID: 29155700 PMCID: PMC5755220 DOI: 10.3791/56034] [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] [Indexed: 01/08/2023] Open
Abstract
Phase-separated giant unilamellar vesicles (GUVs) exhibiting coexisting liquid-ordered and liquid-disordered domains are a common biophysical tool to investigate the lipid raft hypothesis. Numerous studies, however, neglect the impact of physiological solution conditions. On that account, the current work presents the effect of high-salinity buffer and trans-membrane solution asymmetry on liquid-liquid phase separation in charged GUVs grown from dioleylphosphatidylglycerol, egg sphingomyelin, and cholesterol. The effects were studied under isothermal and varying temperature conditions. We describe equipment and experimental strategies applicable for monitoring the stability of coexisting liquid domains in charged vesicles under symmetric and asymmetric high-salinity solution conditions. This includes an approach to prepare charged multicomponent GUVs in high-salinity buffer at high temperatures. The protocol entails the option to perform a partial exchange of the external solution by a simple dilution step while minimizing the vesicle dilution. An alternative approach is presented utilizing a microfluidic device that allows for a complete external solution exchange. The solution effects on phase separation were also studied under varying temperatures. To this end, we present the basic design and utility of an in-house built temperature control chamber. Furthermore, we reflect on the assessment of the GUV phase state, pitfalls associated with it and how to circumvent them.
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21
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Fried ES, Li YM, Gilchrist ML. Phase Composition Control in Microsphere-Supported Biomembrane Systems. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:3028-3039. [PMID: 28198634 PMCID: PMC5568755 DOI: 10.1021/acs.langmuir.6b04150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The popularization of studies in membrane protein lipid phase coexistence has prompted the development of new techniques to construct and study biomimetic systems with cholesterol-rich lipid microdomains. Here, microsphere-supported biomembranes with integrated α-helical peptides, referred to as proteolipobeads (PLBs), were used to model peptide/protein partitioning within DOPC/DPPC/cholesterol phase-separated membranes. Due to the appearance of compositional heterogeneity and impurities in the formation of model PLB assemblies, fluorescence-activated cell sorting (FACS) was used to characterize and sort PLB populations on the basis of disordered phase (Ld) content. In addition, spectral imaging was used to assess the partitioning of FITC-labeled α-helical peptide between fluorescently labeled Ld phase and unlabeled ordered phase (Lo) phase lipid microdomains. The apparent peptide partition coefficient, Kp,app, was measured to be 0.89 ± 0.06, indicating a slight preference of the peptide for the Lo phase. A biomimetic motif of the Lo phase concentration enhancement of the biotinyl-peptide ligand display in proteolipobeads was also observed. Finally, peptide mobility was measured by FRAP separately in each lipid phase, yielding diffusivities of 0.036 ± 0.005 and 0.014 ± 0.003 μm2/s in the Ld and Lo phases, respectively.
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Affiliation(s)
- Eric S. Fried
- Department of Chemical Engineering, The City College of the City University of New York, 140th Street and Convent Avenue, New York, NY 10031
| | - Yue-Ming Li
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
- Program of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University, New York, NY 10021, USA
| | - M. Lane Gilchrist
- Department of Chemical Engineering, The City College of the City University of New York, 140th Street and Convent Avenue, New York, NY 10031
- Department of Biomedical Engineering, The City College of the City University of New York, 140th Street and Convent Avenue, New York, NY 10031
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22
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Stein H, Spindler S, Bonakdar N, Wang C, Sandoghdar V. Production of Isolated Giant Unilamellar Vesicles under High Salt Concentrations. Front Physiol 2017; 8:63. [PMID: 28243205 PMCID: PMC5303729 DOI: 10.3389/fphys.2017.00063] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 01/23/2017] [Indexed: 12/22/2022] Open
Abstract
The cell membrane forms a dynamic and complex barrier between the living cell and its environment. However, its in vivo studies are difficult because it consists of a high variety of lipids and proteins and is continuously reorganized by the cell. Therefore, membrane model systems with precisely controlled composition are used to investigate fundamental interactions of membrane components under well-defined conditions. Giant unilamellar vesicles (GUVs) offer a powerful model system for the cell membrane, but many previous studies have been performed in unphysiologically low ionic strength solutions which might lead to altered membrane properties, protein stability and lipid-protein interaction. In the present work, we give an overview of the existing methods for GUV production and present our efforts on forming single, free floating vesicles up to several tens of μm in diameter and at high yield in various buffer solutions with physiological ionic strength and pH.
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Affiliation(s)
- Hannah Stein
- Friedrich-Alexander University Erlangen-NurembergErlangen, Germany; Max Planck Institute for the Science of LightErlangen, Germany
| | - Susann Spindler
- Friedrich-Alexander University Erlangen-NurembergErlangen, Germany; Max Planck Institute for the Science of LightErlangen, Germany
| | - Navid Bonakdar
- Max Planck Institute for the Science of Light Erlangen, Germany
| | - Chun Wang
- Max Planck Institute for the Science of Light Erlangen, Germany
| | - Vahid Sandoghdar
- Friedrich-Alexander University Erlangen-NurembergErlangen, Germany; Max Planck Institute for the Science of LightErlangen, Germany
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23
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Stein H, Spindler S, Bonakdar N, Wang C, Sandoghdar V. Production of Isolated Giant Unilamellar Vesicles under High Salt Concentrations. Front Physiol 2017; 8:63. [PMID: 28243205 DOI: 10.3389/fphys.2017.00063/full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 01/23/2017] [Indexed: 05/27/2023] Open
Abstract
The cell membrane forms a dynamic and complex barrier between the living cell and its environment. However, its in vivo studies are difficult because it consists of a high variety of lipids and proteins and is continuously reorganized by the cell. Therefore, membrane model systems with precisely controlled composition are used to investigate fundamental interactions of membrane components under well-defined conditions. Giant unilamellar vesicles (GUVs) offer a powerful model system for the cell membrane, but many previous studies have been performed in unphysiologically low ionic strength solutions which might lead to altered membrane properties, protein stability and lipid-protein interaction. In the present work, we give an overview of the existing methods for GUV production and present our efforts on forming single, free floating vesicles up to several tens of μm in diameter and at high yield in various buffer solutions with physiological ionic strength and pH.
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Affiliation(s)
- Hannah Stein
- Friedrich-Alexander University Erlangen-NurembergErlangen, Germany; Max Planck Institute for the Science of LightErlangen, Germany
| | - Susann Spindler
- Friedrich-Alexander University Erlangen-NurembergErlangen, Germany; Max Planck Institute for the Science of LightErlangen, Germany
| | - Navid Bonakdar
- Max Planck Institute for the Science of Light Erlangen, Germany
| | - Chun Wang
- Max Planck Institute for the Science of Light Erlangen, Germany
| | - Vahid Sandoghdar
- Friedrich-Alexander University Erlangen-NurembergErlangen, Germany; Max Planck Institute for the Science of LightErlangen, Germany
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24
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Varela ARP, Ventura AE, Carreira AC, Fedorov A, Futerman AH, Prieto M, Silva LC. Pathological levels of glucosylceramide change the biophysical properties of artificial and cell membranes. Phys Chem Chem Phys 2017; 19:340-346. [DOI: 10.1039/c6cp07227e] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Accumulation of glucosylceramide decreases membrane fluidity in artificial membranes and in cell models of Gaucher disease.
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Affiliation(s)
- Ana R. P. Varela
- iMed.ULisboa – Research Institute for Medicines
- Faculdade de Farmácia
- Universidade de Lisboa
- 1649-003 Lisboa
- Portugal
| | - Ana E. Ventura
- iMed.ULisboa – Research Institute for Medicines
- Faculdade de Farmácia
- Universidade de Lisboa
- 1649-003 Lisboa
- Portugal
| | - Ana C. Carreira
- iMed.ULisboa – Research Institute for Medicines
- Faculdade de Farmácia
- Universidade de Lisboa
- 1649-003 Lisboa
- Portugal
| | - Aleksander Fedorov
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology
- Instituto Superior Técnico
- Universidade de Lisboa
- 1049-001 Lisboa
- Portugal
| | - Anthony H. Futerman
- Department of Biomolecular Sciences
- Weizmann Institute of Science
- Rehovot 76100
- Israel
| | - Manuel Prieto
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology
- Instituto Superior Técnico
- Universidade de Lisboa
- 1049-001 Lisboa
- Portugal
| | - Liana C. Silva
- iMed.ULisboa – Research Institute for Medicines
- Faculdade de Farmácia
- Universidade de Lisboa
- 1649-003 Lisboa
- Portugal
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25
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Bordovsky SS, Wong CS, Bachand GD, Stachowiak JC, Sasaki DY. Engineering Lipid Structure for Recognition of the Liquid Ordered Membrane Phase. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:12527-12533. [PMID: 27564087 DOI: 10.1021/acs.langmuir.6b02636] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The selective partitioning of lipid components in phase-separated membranes is essential for domain formation involved in cellular processes. Identifying and tracking the movement of lipids in cellular systems would be improved if we understood how to achieve selective affinity between fluorophore-labeled lipids and membrane assemblies. Here, we investigated the structure and chemistry of membrane lipids to evaluate lipid designs that partition to the liquid ordered (Lo) phase. A range of fluorophores at the headgroup position and lengths of PEG spacer between the lipid backbone and fluorophore were examined. On a lipid body with saturated palmityl or palmitoyl tails, we found that although the lipid tails can direct selective partitioning to the Lo phase through favorable packing interactions, headgroup hydrophobicity can override the partitioning behavior and direct the lipid to the disordered membrane phase (Ld). The PEG spacer can serve as a buffer to mute headgroup-membrane interactions and thus improve Lo phase partitioning, but its effect is limited with strongly hydrophobic fluorophore headgroups. We present a series of lipid designs leading to the development of novel fluorescently labeled lipids with selective affinity for the Lo phase.
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Affiliation(s)
- Stefan S Bordovsky
- Biotechnology and Bioengineering Department, Sandia National Laboratories , Livermore, California 94551, United States
- Department of Biomedical Engineering, The University of Texas at Austin , Austin, Texas 78705, United States
| | - Christopher S Wong
- Biotechnology and Bioengineering Department, Sandia National Laboratories , Livermore, California 94551, United States
| | - George D Bachand
- Nanosystems Synthesis/Analysis Department, Sandia National Laboratories , Albuquerque, New Mexico 87185, United States
| | - Jeanne C Stachowiak
- Department of Biomedical Engineering, The University of Texas at Austin , Austin, Texas 78705, United States
| | - Darryl Y Sasaki
- Biotechnology and Bioengineering Department, Sandia National Laboratories , Livermore, California 94551, United States
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26
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Sturzenegger F, Robinson T, Hess D, Dittrich PS. Membranes under shear stress: visualization of non-equilibrium domain patterns and domain fusion in a microfluidic device. SOFT MATTER 2016; 12:5072-5076. [PMID: 27241894 DOI: 10.1039/c6sm00049e] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this study we investigate the effect of shear force on lipid membranes induced by external fluid flow. We use giant unilamellar vesicles (GUVs) as simple cell models and chose a ternary lipid mixture that exhibits liquid-ordered and liquid-disordered domains. These domains are stained with different dyes to allow visualization of changes within the membrane after the application of flow. A microfluidic device served as a valuable platform to immobilize the vesicles and apply shear forces of a defined strength. Moreover, integration of valves allowed us to stop the flow instantaneously and visualize the relaxing domain patterns by means of high-resolution fluorescence microscopy. We observed the formation of transient, non-deterministic patterns of the formerly round domains during application of flow. When the flow is stopped, round domains are formed again on a time scale of ms to s. At longer time scales of several seconds to minutes, the domains fuse into larger domains until they reach equilibrium. These processes are accelerated with increasing temperature and vesicles with budding domains do not fuse unless the temperature is elevated. Our results show the strong effect of the flow on the lipid membrane and we believe that this phenomenon plays a crucial role in the processes of mechanotransduction in living cells.
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27
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Lira RB, Steinkühler J, Knorr RL, Dimova R, Riske KA. Posing for a picture: vesicle immobilization in agarose gel. Sci Rep 2016; 6:25254. [PMID: 27140695 PMCID: PMC4853705 DOI: 10.1038/srep25254] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 04/13/2016] [Indexed: 01/14/2023] Open
Abstract
Taking a photo typically requires the object of interest to stand still. In science, imaging is potentiated by optical and electron microscopy. However, living and soft matter are not still. Thus, biological preparations for microscopy usually include a fixation step. Similarly, immobilization strategies are required for or substantially facilitate imaging of cells or lipid vesicles, and even more so for acquiring high-quality data via fluorescence-based techniques. Here, we describe a simple yet efficient method to immobilize objects such as lipid vesicles with sizes between 0.1 and 100 μm using agarose gel. We show that while large and giant unilamellar vesicles (LUVs and GUVs) can be caged in the pockets of the gel meshwork, small molecules, proteins and micelles remain free to diffuse through the gel and interact with membranes as in agarose-free solutions, and complex biochemical reactions involving several proteins can proceed in the gel. At the same time, immobilization in agarose has no adverse effect on the GUV size and stability. By applying techniques such as FRAP and FCS, we show that the lateral diffusion of lipids is not affected by the gel. Finally, our immobilization strategy allows capturing high-resolution 3D images of GUVs.
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Affiliation(s)
- Rafael B. Lira
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, Brazil
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Jan Steinkühler
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Roland L. Knorr
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Rumiana Dimova
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Karin A. Riske
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, Brazil
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28
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Varela ARP, Couto AS, Fedorov A, Futerman AH, Prieto M, Silva LC. Glucosylceramide Reorganizes Cholesterol-Containing Domains in a Fluid Phospholipid Membrane. Biophys J 2016; 110:612-622. [PMID: 26840726 PMCID: PMC4744164 DOI: 10.1016/j.bpj.2015.12.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 11/23/2015] [Accepted: 12/09/2015] [Indexed: 12/18/2022] Open
Abstract
Glucosylceramide (GlcCer), one of the simplest glycosphingolipids, plays key roles in physiology and pathophysiology. It has been suggested that GlcCer modulates cellular events by forming specialized domains. In this study, we investigated the interplay between GlcCer and cholesterol (Chol), an important lipid involved in the formation of liquid-ordered (lo) phases. Using fluorescence microscopy and spectroscopy, and dynamic and electrophoretic light scattering, we characterized the interaction between these lipids in different pH environments. A quantitative description of the phase behavior of the ternary unsaturated phospholipid/Chol/GlcCer mixture is presented. The results demonstrate coexistence between lo and liquid-disordered (ld) phases. However, the extent of lo/ld phase separation is sparse, mainly due to the ability of GlcCer to segregate into tightly packed gel domains. As a result, the phase diagram of these mixtures is characterized by an extensive three-phase coexistence region of fluid (ld-phospholipid enriched)/lo (Chol enriched)/gel (GlcCer enriched). Moreover, the results show that upon acidification, GlcCer solubility in the lo phase is increased, leading to a larger lo/ld coexistence region. Quantitative analyses allowed us to determine the differences in the composition of the phases at neutral and acidic pH. These results predict the impact of GlcCer on domain formation and membrane organization in complex biological membranes, and provide a background for unraveling the relationship between the biophysical properties of GlcCer and its biological action.
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Affiliation(s)
- Ana R P Varela
- iMed.ULisboa-Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Lisbon, Portugal; Centro de Química-Física Molecular and IN-Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal; Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - André Sá Couto
- iMed.ULisboa-Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Lisbon, Portugal
| | - Aleksander Fedorov
- Centro de Química-Física Molecular and IN-Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Anthony H Futerman
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Manuel Prieto
- Centro de Química-Física Molecular and IN-Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Liana C Silva
- iMed.ULisboa-Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Lisbon, Portugal.
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29
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Sarmento MJ, Pinto SN, Coutinho A, Prieto M, Fernandes F. Accurate quantification of inter-domain partition coefficients in GUVs exhibiting lipid phase coexistence. RSC Adv 2016. [DOI: 10.1039/c6ra13170k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Giant unilamellar vesicles (GUVs) with phase coexistence allow for the recovery of inter-domain partition coefficients (Kp) of fluorescent molecules through comparison of fluorescence intensities in each phase.
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Affiliation(s)
- M. J. Sarmento
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology
- Instituto Superior Técnico
- University of Lisbon
- Lisbon
- Portugal
| | - S. N. Pinto
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology
- Instituto Superior Técnico
- University of Lisbon
- Lisbon
- Portugal
| | - A. Coutinho
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology
- Instituto Superior Técnico
- University of Lisbon
- Lisbon
- Portugal
| | - M. Prieto
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology
- Instituto Superior Técnico
- University of Lisbon
- Lisbon
- Portugal
| | - F. Fernandes
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology
- Instituto Superior Técnico
- University of Lisbon
- Lisbon
- Portugal
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30
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Magalhães S, Duarte S, Monteiro GA, Fernandes F. Quantitative evaluation of DNA dissociation from liposome carriers and DNA escape from endosomes during lipid-mediated gene delivery. Hum Gene Ther Methods 2015; 25:303-13. [PMID: 25285806 DOI: 10.1089/hgtb.2014.080] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Nonviral vectors are highly attractive for gene therapy from a clinical point of view, and cationic lipid nanoparticles in particular have generated considerable interest. However, despite considerable recent advances, problems associated with low transfection efficiencies remain to be resolved to fully meet the potential of these vectors. The trafficking of plasmid DNA (pDNA) from the extracellular space up to the nucleus is prevented by several barriers, including liposome/pDNA dissociation within the endosome and pDNA escape into the cytosol. The aim of this work was to develop and optimize a tool that could offer simultaneous quantitative information both on the intracellular dissociation of oligonucleotides from lipid nanoparticles, and on the DNA escape from endocytic compartments. The ability to follow in real time both of these processes simultaneously (in a quantitative manner) is expected to be of high value in the rationalization and conception of new lipid nanoparticle vectors for gene delivery for therapeutic purposes. To this effect, a combination of Förster resonance energy transfer (FRET) and colocalization microscopy was employed. We show that it is possible to distinguish between liposome/pDNA dissociation and depletion of DNA within endosomes, providing resolution for the detection of intermediate species between endocytic particles with intact lipoplexes and endosomes devoid of DNA because of DNA escape or degradation. We demonstrate that after endocytosis, exceptionally few endocytic particles are found to exhibit simultaneously DNA/lipid colocalization and low FRET (DNA/lipid dissociation). These results clearly point to an extremely short-lived state for free plasmid within endosomes, which either escapes at once to the cytosol or is degraded within the endocytic compartment (because of exposure of DNA). It is possible that this limitation greatly contributes to reduction in probability of successful gene delivery through cationic lipid particles.
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Affiliation(s)
- Salomé Magalhães
- 1 Institute of Biotechnology and Bioengineering, Centre for Chemical and Biological Engineering, Instituto Superior Técnico, Universidade de Lisboa , 1049-001 Lisbon, Portugal
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31
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Momin N, Lee S, Gadok AK, Busch DJ, Bachand GD, Hayden CC, Stachowiak JC, Sasaki DY. Designing lipids for selective partitioning into liquid ordered membrane domains. SOFT MATTER 2015; 11:3241-3250. [PMID: 25772372 DOI: 10.1039/c4sm02856b] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Self-organization of lipid molecules into specific membrane phases is key to the development of hierarchical molecular assemblies that mimic cellular structures. While the packing interaction of the lipid tails should provide the major driving force to direct lipid partitioning to ordered or disordered membrane domains, numerous examples show that the headgroup and spacer play important but undefined roles. We report here the development of several new biotinylated lipids that examine the role of spacer chemistry and structure on membrane phase partitioning. The new lipids were prepared with varying lengths of low molecular weight polyethylene glycol (EGn) spacers to examine how spacer hydrophilicity and length influence their partitioning behavior following binding with FITC-labeled streptavidin in liquid ordered (Lo) and liquid disordered (Ld) phase coexisting membranes. Partitioning coefficients (Kp Lo/Ld) of the biotinylated lipids were determined using fluorescence measurements in studies with giant unilamellar vesicles (GUVs). Compared against DPPE-biotin, DPPE-cap-biotin, and DSPE-PEG2000-biotin lipids, the new dipalmityl-EGn-biotin lipids exhibited markedly enhanced partitioning into liquid ordered domains, achieving Kp of up to 7.3 with a decaethylene glycol spacer (DP-EG10-biotin). We further demonstrated biological relevance of the lipids with selective partitioning to lipid raft-like domains observed in giant plasma membrane vesicles (GPMVs) derived from mammalian cells. Our results found that the spacer group not only plays a pivotal role for designing lipids with phase selectivity but may also influence the structural order of the domain assemblies.
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Affiliation(s)
- Noor Momin
- Sandia National Laboratories, Biotechnology and Bioengineering Dept., Livermore, CA, USA.
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32
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Hentrich C, Szostak JW. Controlled growth of filamentous fatty acid vesicles under flow. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:14916-14925. [PMID: 25402759 PMCID: PMC4985002 DOI: 10.1021/la503933x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 11/14/2014] [Indexed: 06/01/2023]
Abstract
The earliest forms of cellular life would have required a membrane compartment capable of growth and division. Fatty acid vesicles are an attractive model of protocell membranes, as they can grow into filamentous vesicles that readily divide while retaining their contents. In order to study vesicle growth, we have developed a method for immobilizing multilamellar fatty acid vesicles on modified glass surfaces and inducing filamentous membrane growth under flow. Filament formation strictly depended on the presence of freshly neutralized fatty acid micelles in the flow chamber. Using light microscopy, we observed a strong dependence of initial growth velocity on initial vesicle size, suggesting that new fatty acid molecules were incorporated into the membrane over the entire external surface of the vesicle. We examined the influences of flow rate, fatty acid concentration, and salt concentration on filamentous growth and observed drastic shape changes, including membrane pearling, of preexisting membrane tubules in response to osmotic stress. These results illustrate the versatility of flow studies for exploring the process of fatty acid vesicle growth following exposure to free fatty acids.
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Affiliation(s)
- Christian Hentrich
- Howard
Hughes Medical Institute, Department of Molecular Biology and Center
for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, United States
- Department
of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Jack W. Szostak
- Howard
Hughes Medical Institute, Department of Molecular Biology and Center
for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, United States
- Department
of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
- Department
of Chemistry and Chemical Biology, Harvard
University, 12 Oxford
St., Cambridge, Massachusetts 02138, United States
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33
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Varela ARP, Gonçalves da Silva AMPS, Fedorov A, Futerman AH, Prieto M, Silva LC. Influence of intracellular membrane pH on sphingolipid organization and membrane biophysical properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:4094-4104. [PMID: 24654655 DOI: 10.1021/la5003397] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Glucosylceramide (GlcCer) is a signaling lipid involved in the regulation of several cellular processes. It is present in different organelles, including the plasma membrane, Golgi apparatus, endoplasmic reticulum, and lysosomes. Accordingly, GlcCer is exposed to different pH environments in each organelle, which may lead to alterations in its properties and lateral organization and subsequent biological outcome. In this study, we addressed the effect of pH on the biophysical behavior of this lipid and other structurally related sphingolipids (SLs). Membranes composed of POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) and C16-GlcCer, sphingomyelin, and different acyl chain ceramides were characterized by fluorescence spectroscopy, confocal microscopy, and surface pressure-area measurements under neutral and acidic conditions. The results show that changing the pH from 7.4 to 5.5 has a larger impact on C16-GlcCer-containing membranes compared to other SLs. In addition, acidification mainly affects the organization and packing properties of the GlcCer-enriched gel phase, suggesting that the interactions established by the glucose moiety, in the GlcCer molecule, are those most affected by the increase in the acidity. These results further highlight the role of GlcCer as a modulator of membrane biophysical properties and will possibly contribute to the understanding of its biological function in different organelles.
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Affiliation(s)
- Ana R P Varela
- iMed.UL, Faculdade de Farmácia, Universidade de Lisboa , Avenida Professor Gama Pinto, 1649-003 Lisboa, Portugal
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34
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Bagatolli LA, Needham D. Quantitative optical microscopy and micromanipulation studies on the lipid bilayer membranes of giant unilamellar vesicles. Chem Phys Lipids 2014; 181:99-120. [PMID: 24632023 DOI: 10.1016/j.chemphyslip.2014.02.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 02/25/2014] [Accepted: 02/26/2014] [Indexed: 12/01/2022]
Abstract
This manuscript discusses basic methodological aspects of optical microscopy and micromanipulation methods to study membranes and reviews methods to generate giant unilamellar vesicles (GUVs). In particular, we focus on the use of fluorescence microscopy and micropipet manipulation techniques to study composition-structure-property materials relationships of free-standing lipid bilayer membranes. Because their size (∼5-100 μm diameter) that is well above the resolution limit of regular light microscopes, GUVs are suitable membrane models for optical microscopy and micromanipulation experimentation. For instance, using different fluorescent reporters, fluorescence microscopy allows strategies to study membrane lateral structure/dynamics at the level of single vesicles of diverse compositions. The micropipet manipulation technique on the other hand, uses Hoffman modulation contrast microscopy and allows studies on the mechanical, thermal, molecular exchange and adhesive-interactive properties of compositionally different membranes under controlled environmental conditions. The goal of this review is to (i) provide a historical perspective for both techniques; (ii) present and discuss some of their most important contributions to our understanding of lipid bilayer membranes; and (iii) outline studies that would utilize both techniques simultaneously on the same vesicle thus bringing the ability to characterize structure and strain responses together with the direct application of well-defined stresses to a single membrane or observe the effects of adhesive spreading. Knowledge gained by these studies has informed several applications of lipid membranes including their use as lung surfactants and drug delivery systems for cancer.
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Affiliation(s)
- Luis A Bagatolli
- Membrane Biophysics and Biophotonics Group/MEMPHYS - Center for Biomembrane Physics, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark.
| | - David Needham
- DNRF Niels Bohr Professorship, Center for Single Particle Science and Engineering, Institute for Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark; Department of Mechanical Engineering and Material Science, Duke University, Durham, NC, USA
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35
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Melo AM, Loura LMS, Fernandes F, Villalaín J, Prieto M, Coutinho A. Electrostatically driven lipid-lysozyme mixed fibers display a multilamellar structure without amyloid features. SOFT MATTER 2014; 10:840-850. [PMID: 24651998 DOI: 10.1039/c3sm52586d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Understanding the interactions between anionic lipid membranes and amyloidogenic proteins/peptides is key to elucidate the molecular mechanisms underlying the membrane-driven amyloid fiber formation. Here, hen egg-white lysozyme was used as a model protein to test whether this same process also occurs with non-amyloidogenic lipid-binding proteins/peptides. A complementary set of biophysical techniques was employed to study the structure and dynamics of the lipid-lysozyme mixed fibers produced at a low lipid/protein molar ratio that have been proposed earlier to present "amyloid-like" characteristics. The multilamellar architecture of these elongated mesoscopic structures was established by performing time-resolved Förster resonance energy transfer measurements, at both bulk (ensemble) and single-fiber level. The predominantly oligomeric lysozyme and phospholipids were both found to display significantly decreased lateral mobility when embedded in these mixed fibers. Notably, two-photon microscopy of Laurdan revealed that a pronounced membrane surface dehydration/increased molecular interfacial packing was produced exclusively in these elongated mixed supramolecular fibers present in the highly polymorphic samples. Infrared spectroscopic studies of lysozyme in these samples further showed that this protein did not exhibit a rich β-sheet structure characteristic of amyloid fibrils. These results support the conclusion that negatively charged lipid membranes do not have the general ability to trigger amyloid fibril formation of non-amyloidogenic proteins.
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Affiliation(s)
- Ana M Melo
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
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36
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Sarmento MJ, Coutinho A, Fedorov A, Prieto M, Fernandes F. Ca(2+) induces PI(4,5)P2 clusters on lipid bilayers at physiological PI(4,5)P2 and Ca(2+) concentrations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:822-30. [PMID: 24316170 DOI: 10.1016/j.bbamem.2013.11.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 11/22/2013] [Accepted: 11/26/2013] [Indexed: 01/22/2023]
Abstract
Calcium has been shown to induce clustering of PI(4,5)P2 at high and non-physiological concentrations of both the divalent ion and the phosphatidylinositol, or on supported lipid monolayers. In lipid bilayers at physiological conditions, clusters are not detected through microscopic techniques. Here, we aimed to determine through spectroscopic methodologies if calcium plays a role in PI(4,5)P2 lateral distribution on lipid bilayers under physiological conditions. Using several different approaches which included information on fluorescence quantum yield, polarization, spectra and diffusion properties of a fluorescent derivative of PI(4,5)P2 (TopFluor(TF)-PI(4,5)P2), we show that Ca(2+) promotes PI(4,5)P2 clustering in lipid bilayers at physiological concentrations of both Ca(2+) and PI(4,5)P2. Fluorescence depolarization data of TF-PI(4,5)P2 in the presence of calcium suggests that under physiological concentrations of PI(4,5)P2 and calcium, the average cluster size comprises ~15 PI(4,5)P2 molecules. The presence of Ca(2+)-induced PI(4,5)P2 clusters is supported by FCS data. Additionally, calcium mediated PI(4,5)P2 clustering was more pronounced in liquid ordered (lo) membranes, and the PI(4,5)P2-Ca(2+) clusters presented an increased affinity for lo domains. In this way, PI(4,5)P2 could function as a lipid calcium sensor and the increased efficiency of calcium-mediated PI(4,5)P2 clustering on lo domains might provide targeted nucleation sites for PI(4,5)P2 clusters upon calcium stimulus.
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Affiliation(s)
- Maria J Sarmento
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Ana Coutinho
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal; Departamento de Química e Bioquímica, FCUL, University of Lisbon, Lisbon, Portugal
| | - Aleksander Fedorov
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Manuel Prieto
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Fabio Fernandes
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal.
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37
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Mello-Vieira J, Sousa T, Coutinho A, Fedorov A, Lucas SD, Moreira R, Castro RE, Rodrigues CM, Prieto M, Fernandes F. Cytotoxic bile acids, but not cytoprotective species, inhibit the ordering effect of cholesterol in model membranes at physiologically active concentrations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2152-63. [DOI: 10.1016/j.bbamem.2013.05.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 05/22/2013] [Accepted: 05/22/2013] [Indexed: 01/10/2023]
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38
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Varela AR, Gonçalves da Silva AM, Fedorov A, Futerman AH, Prieto M, Silva LC. Effect of glucosylceramide on the biophysical properties of fluid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013. [DOI: 10.1016/j.bbamem.2012.11.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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