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Wardhani K, Levina A, Sun B, Zou H, Grau GER, Keene FR, Collins JG, Lay PA. Tetranuclear Polypyridylruthenium(II) Complexes as Selective Nucleic Acid Stains for Flow Cytometric Analysis of Monocytic and Epithelial Lung Carcinoma Large Extracellular Vesicles. Biomolecules 2024; 14:664. [PMID: 38927067 PMCID: PMC11202172 DOI: 10.3390/biom14060664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 05/31/2024] [Accepted: 06/02/2024] [Indexed: 06/28/2024] Open
Abstract
Selective staining of extracellular vesicles (EVs) is a major challenge for diagnostic and therapeutic applications. Herein, the EV labeling properties of a new class of tetranuclear polypyridylruthenium(II) complexes, Rubb7-TNL and Rubb7-TL, as phosphorescent stains are described. These new stains have many advantages over standard stains to detect and characterize EVs, including: high specificity for EV staining versus cell staining; high phosphorescence yields; photostability; and a lack of leaching from EVs until incorporation with target cells. As an example of their utility, large EVs released from control (basal) or lipopolysaccharide (LPS)-stimulated THP-1 monocytic leukemia cells were studied as a model of immune system EVs released during bacterial infection. Key findings from EV staining combined with flow cytometry were as follows: (i) LPS-stimulated THP-1 cells generated significantly larger and more numerous large EVs, as compared with those from unstimulated cells; (ii) EVs retained native EV physical properties after staining; and (iii) the new stains selectively differentiated intact large EVs from artificial liposomes, which are models of cell membrane fragments or other lipid-containing debris, as well as distinguished two distinct subpopulations of monocytic EVs within the same experiment, as a result of biochemical differences between unstimulated and LPS-stimulated monocytes. Comparatively, the staining patterns of A549 epithelial lung carcinoma-derived EVs closely resembled those of THP-1 cell line-derived EVs, which highlighted similarities in their selective staining despite their distinct cellular origins. This is consistent with the hypothesis that these new phosphorescent stains target RNA within the EVs.
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Affiliation(s)
- Kartika Wardhani
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia; (K.W.); (H.Z.)
- Biochemistry and Biotechnology (B-TEK) Group, Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Aviva Levina
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia; (K.W.); (H.Z.)
| | - Biyun Sun
- School of Natural Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109, Australia;
| | - Haipei Zou
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia; (K.W.); (H.Z.)
| | - Georges E. R. Grau
- Sydney Nano, The University of Sydney, Sydney, NSW 2006, Australia;
- Sydney Cancer Network, The University of Sydney, Sydney, NSW 2006, Australia
- Marie Bashir Institute, The University of Sydney, Sydney, NSW 2006, Australia
- Vascular Immunology Unit, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
| | - F. Richard Keene
- Discipline of Chemistry, School of Physics, Chemistry, and Earth Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
- Australian Institute of Tropical Health and Medicine/Centre for Molecular Therapeutics, James Cook University, Townsville, QLD 4811, Australia
| | - J. Grant Collins
- School of Science, The University of New South Wales, Australian Defence Force Academy, Canberra, ACT 2612, Australia;
| | - Peter A. Lay
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia; (K.W.); (H.Z.)
- Sydney Nano, The University of Sydney, Sydney, NSW 2006, Australia;
- Sydney Cancer Network, The University of Sydney, Sydney, NSW 2006, Australia
- Marie Bashir Institute, The University of Sydney, Sydney, NSW 2006, Australia
- Sydney Analytical, The University of Sydney, Sydney, NSW 2006, Australia
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2
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Mach M, Płachta Ł, Wydro P. Study of the correlation between the structure of selected triester of phosphatidylcholine and their impact on physicochemical properties of model mammalian membranes. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184254. [PMID: 37989397 DOI: 10.1016/j.bbamem.2023.184254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/14/2023] [Accepted: 11/14/2023] [Indexed: 11/23/2023]
Abstract
Cationic lipids are synthetic compounds of amphiphilic character used in Drug Delivery Systems (DDS), especially in gene therapy, as the carriers of genetic material. As it is known, the main limitation of the application of cationic lipids in DDS is their high cytotoxicity after in vivo administration and low bioactivity. This is probably related to not fully known the relationship between the lipid structure and its activity as well as the mechanism of lipofection or drug delivery. Therefore, in this work we determined the impact of a selected group of cationic lipids - triesters of phosphatidylcholine (Et-PCs) - differing in their hydrophobic structure on model mammalian membranes. In the research, as model systems, Langmuir monolayers and liposomes were applied. It was shown that the incorporation of Et-PCs into model mammalian membranes weakens interactions between lipids, causing the increase of fluidity, disordering degree and permeability of membrane. The destabilization of the membrane in this way can facilitate the entry of drugs, carried inside cationic liposomes, into the pathological cell. Moreover, the studies prove that the structure of the hydrophobic part of cationic lipids also affects the properties of lipid membranes.
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Affiliation(s)
- Marzena Mach
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland.
| | - Łukasz Płachta
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland; Jagiellonian University, Doctoral School of Exact and Natural Sciences, Prof. Łojasiewicza 11, 30-348 Kraków, Poland
| | - Paweł Wydro
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland
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3
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Prevete G, Simonis B, Mazzonna M, Mariani F, Donati E, Sennato S, Ceccacci F, Bombelli C. Resveratrol and Resveratrol-Loaded Galactosylated Liposomes: Anti-Adherence and Cell Wall Damage Effects on Staphylococcus aureus and MRSA. Biomolecules 2023; 13:1794. [PMID: 38136664 PMCID: PMC10741626 DOI: 10.3390/biom13121794] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/07/2023] [Accepted: 12/11/2023] [Indexed: 12/24/2023] Open
Abstract
Antibiotic resistance due to bacterial biofilm formation is a major global health concern that makes the search for new therapeutic approaches an urgent need. In this context,, trans-resveratrol (RSV), a polyphenolic natural substance, seems to be a good candidate for preventing and eradicating biofilm-associated infections but its mechanism of action is poorly understood. In addition, RSV suffers from low bioavailability and chemical instability in the biological media that make its encapsulation in delivery systems necessary. In this work, the anti-biofilm activity of free RSV was investigated on Staphylococcus aureus and, to highlight the possible mechanism of action, we studied the anti-adherence activity and also the cell wall damage on a MRSA strain. Free RSV activity was compared to that of RSV loaded in liposomes, specifically neutral liposomes (L = DOPC/Cholesterol) and cationic liposomes (LG = DOPC/Chol/GLT1) characterized by a galactosylated amphiphile (GLT1) that promotes the interaction with bacteria. The results indicate that RSV loaded in LG has anti-adherence and anti-biofilm activity higher than free RSV. On the other side, free RSV has a higher bacterial-growth-inhibiting effect than encapsulated RSV and it can damage cell walls by creating pores; however, this effect can not prevent bacteria from growing again. This RSV ability may underlie its bacteriostatic activity.
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Affiliation(s)
- Giuliana Prevete
- Department of Chemistry and Technology of Drug, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy;
- Institute for Biological Systems of Italian National Research Council (ISB-CNR), Area della Ricerca di Roma 1, Via Salaria Km 29,300, 00015 Monterotondo, Italy;
| | - Beatrice Simonis
- Institute for Biological Systems of Italian National Research Council (ISB-CNR), Secondary Office of Rome-Reaction Mechanisms c/o Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy (F.C.); (C.B.)
| | - Marco Mazzonna
- Institute for Biological Systems of Italian National Research Council (ISB-CNR), Area della Ricerca di Roma 1, Via Salaria Km 29,300, 00015 Monterotondo, Italy;
| | - Francesca Mariani
- Institute for Biological Systems of Italian National Research Council (ISB-CNR), Area della Ricerca di Roma 1, Via Salaria Km 29,300, 00015 Monterotondo, Italy;
| | - Enrica Donati
- Institute for Biological Systems of Italian National Research Council (ISB-CNR), Area della Ricerca di Roma 1, Via Salaria Km 29,300, 00015 Monterotondo, Italy;
| | - Simona Sennato
- Institute for Complex Systems of the Italian National Research Council (ISC-CNR), Sede Sapienza c/o Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy;
| | - Francesca Ceccacci
- Institute for Biological Systems of Italian National Research Council (ISB-CNR), Secondary Office of Rome-Reaction Mechanisms c/o Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy (F.C.); (C.B.)
| | - Cecilia Bombelli
- Institute for Biological Systems of Italian National Research Council (ISB-CNR), Secondary Office of Rome-Reaction Mechanisms c/o Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy (F.C.); (C.B.)
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4
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Li Q, Ferrare JT, Silver J, Wilson JO, Arteaga-Castaneda L, Qiu W, Vershinin M, King SJ, Neuman KC, Xu J. Cholesterol in the cargo membrane amplifies tau inhibition of kinesin-1-based transport. Proc Natl Acad Sci U S A 2023; 120:e2212507120. [PMID: 36626558 PMCID: PMC9934065 DOI: 10.1073/pnas.2212507120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 12/08/2022] [Indexed: 01/11/2023] Open
Abstract
Intracellular cargos are often membrane-enclosed and transported by microtubule-based motors in the presence of microtubule-associated proteins (MAPs). Whereas increasing evidence reveals how MAPs impact the interactions between motors and microtubules, critical questions remain about the impact of the cargo membrane on transport. Here we combined in vitro optical trapping with theoretical approaches to determine the effect of a lipid cargo membrane on kinesin-based transport in the presence of MAP tau. Our results demonstrate that attaching kinesin to a fluid lipid membrane reduces the inhibitory effect of tau on kinesin. Moreover, adding cholesterol, which reduces kinesin diffusion in the cargo membrane, amplifies the inhibitory effect of tau on kinesin binding in a dosage-dependent manner. We propose that reduction of kinesin diffusion in the cargo membrane underlies the effect of cholesterol on kinesin binding in the presence of tau, and we provide a simple model for this proposed mechanism. Our study establishes a direct link between cargo membrane cholesterol and MAP-based regulation of kinesin-1. The cholesterol effects uncovered here may more broadly extend to other lipid alterations that impact motor diffusion in the cargo membrane, including those associated with aging and neurological diseases.
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Affiliation(s)
- Qiaochu Li
- Department of Physics, University of California, Merced, CA95343
| | - James T. Ferrare
- Laboratory of Single Molecule Biophysics, National Heart, Lung and Blood Institute, NIH, Bethesda, MD20892
| | - Jonathan Silver
- Laboratory of Single Molecule Biophysics, National Heart, Lung and Blood Institute, NIH, Bethesda, MD20892
| | - John O. Wilson
- Department of Physics, University of California, Merced, CA95343
| | | | - Weihong Qiu
- Department of Physics, Oregon State University, Corvallis, OR97331
| | - Michael Vershinin
- Department of Physics and Astronomy, University of Utah, Salt Lake City, UT84112
| | - Stephen J. King
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL32827
| | - Keir C. Neuman
- Laboratory of Single Molecule Biophysics, National Heart, Lung and Blood Institute, NIH, Bethesda, MD20892
| | - Jing Xu
- Department of Physics, University of California, Merced, CA95343
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5
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Song ES, Oh Y, Sung BJ. Interdomain exchange and the flip-flop of cholesterol in ternary component lipid membranes and their effects on heterogeneous cholesterol diffusion. Phys Rev E 2021; 104:044402. [PMID: 34781553 DOI: 10.1103/physreve.104.044402] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 09/17/2021] [Indexed: 11/07/2022]
Abstract
Cell membranes are heterogeneous with a variety of lipids, cholesterol, and proteins and are composed of domains of different compositions. Such heterogeneous environments make the transport of cholesterol complicated: cholesterol not only diffuses within a particular domain but also travels between domains. Cholesterol also flip-flops between upper and lower leaflets such that cholesterol may reside both within leaflets and in the central region between two leaflets. How the presence of multiple domains and the interdomain exchange of cholesterol would affect the cholesterol transport, however, remains elusive. In this study, therefore, we perform molecular dynamics simulations up to 100μs for ternary component lipid membranes, which consist of saturated lipids (dipalmitoylphosphatidylcholine, DPPC), unsaturated lipids (dilinoleylphosphatidylcholine, DIPC), and cholesterol. The ternary component membranes in our simulations form two domains readily: DPPC and DIPC domains. We find that the diffusion of cholesterol molecules is much more heterogeneous and non-Gaussian than expected for binary component lipid membranes of lipids and cholesterol. The non-Gaussian parameter of the cholesterol molecules is about four times larger in the ternary component lipid membranes than in the binary component lipid membranes. Such non-Gaussian and heterogeneous transport of cholesterol arises from the interplay among the interdomain kinetics, the different diffusivity of cholesterol in different domains, and the flip-flop of cholesterol. This suggests that in cell membranes that consist of various domains and proteins, the cholesterol transport can be very heterogeneous. We also find that the mechanism of the interdomain exchange differs for different domains: cholesterol tends to exit the DIPC domain along the central region of the membrane for the DIPC-to-DPPC transition, while the cholesterol is likely to exit the DPPC domain within the membrane leaflet for the DPPC-to-DIPC transition. Also, the interdomain exchange kinetics of cholesterol for the DPPC-to-DIPC transition is up to 7.9 times slower than the DIPC-to-DPPC transition.
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Affiliation(s)
- Eun Sub Song
- Department of Chemistry, Sogang University, Seoul 04107, Republic of Korea
| | - Younghoon Oh
- Department of Chemistry, Sogang University, Seoul 04107, Republic of Korea
| | - Bong June Sung
- Department of Chemistry, Sogang University, Seoul 04107, Republic of Korea
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6
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Weigle AT, Carr M, Shukla D. Impact of Increased Membrane Realism on Conformational Sampling of Proteins. J Chem Theory Comput 2021; 17:5342-5357. [PMID: 34339605 DOI: 10.1021/acs.jctc.1c00276] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The realism and accuracy of lipid bilayer simulations through molecular dynamics (MD) are heavily dependent on the lipid composition. While the field is pushing toward implementing more heterogeneous and realistic membrane compositions, a lack of high-resolution lipidomic data prevents some membrane protein systems from being modeled with the highest level of realism. Given the additional diversity of real-world cellular membranes and protein-lipid interactions, it is still not fully understood how altering membrane complexity affects modeled membrane protein functions or if it matters over long-timescale simulations. This is especially true for organisms whose membrane environments have little to no computational study, such as the plant plasma membrane. Tackling these issues in tandem, a generalized, realistic, and asymmetric plant plasma membrane with more than 10 different lipid species is constructed herein. Classical MD simulations of pure membrane constructs were performed to evaluate how altering the compositional complexity of the membrane impacted the plant membrane properties. The apo form of a plant sugar transporter, OsSWEET2b, was inserted into membrane models where lipid diversity was calculated in either a size-dependent or size-independent manner. An adaptive sampling simulation regime validated by Markov-state models was performed to capture the gating dynamics of OsSWEET2b in each of these membrane constructs. In comparison to previous OsSWEET2b simulations performed in a pure POPC bilayer, we confirm that simulations performed within a native-like membrane composition alter the stabilization of apo OsSWEET2b conformational states by ∼1 kcal/mol. The free-energy barriers of intermediate conformational states decrease when realistic membrane complexity is simplified, albeit roughly within sampling error, suggesting that protein-specific responses to membranes differ due to altered packing caused by compositional fluctuations. This work serves as a case study where a more realistic bilayer composition makes unbiased conformational sampling easier to achieve than with simplified bilayers.
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Affiliation(s)
- Austin T Weigle
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Matthew Carr
- Independent Software Development Provider310 East Marlette Avenue, Phoenix, Arizona 85012, United States
| | - Diwakar Shukla
- Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Center for Digital Agriculture, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,NIH Center for Macromolecular Modeling and Bioinformatics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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7
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Liu Z, Wang S, Tapeinos C, Torrieri G, Känkänen V, El-Sayed N, Python A, Hirvonen JT, Santos HA. Non-viral nanoparticles for RNA interference: Principles of design and practical guidelines. Adv Drug Deliv Rev 2021; 174:576-612. [PMID: 34019958 DOI: 10.1016/j.addr.2021.05.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 05/04/2021] [Accepted: 05/15/2021] [Indexed: 02/08/2023]
Abstract
Ribonucleic acid interference (RNAi) is an innovative treatment strategy for a myriad of indications. Non-viral synthetic nanoparticles (NPs) have drawn extensive attention as vectors for RNAi due to their potential advantages, including improved safety, high delivery efficiency and economic feasibility. However, the complex natural process of RNAi and the susceptible nature of oligonucleotides render the NPs subject to particular design principles and requirements for practical fabrication. Here, we summarize the requirements and obstacles for fabricating non-viral nano-vectors for efficient RNAi. To address the delivery challenges, we discuss practical guidelines for materials selection and NP synthesis in order to maximize RNA encapsulation efficiency and protection against degradation, and to facilitate the cytosolic release of oligonucleotides. The current status of clinical translation of RNAi-based therapies and further perspectives for reducing the potential side effects are also reviewed.
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8
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El Hajj F, Fuchs PFJ, Urbach W, Nassereddine M, Hamieh S, Taulier N. Molecular Study of Ultrasound-Triggered Release of Fluorescein from Liposomes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:3868-3881. [PMID: 33769822 DOI: 10.1021/acs.langmuir.0c03444] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Several investigations have suggested that ultrasound triggers the release of drugs encapsulated into liposomes at acoustic pressures low enough to avoid cavitation or high hyperthermia. However, the mechanism leading to this triggered release as well as the adequate composition of the liposome membrane remains unknown. Here, we investigate the ultrasound-triggered release of fluorescein disodium salt encapsulated into liposomes made of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) or 1,2-distearoylphosphatidyl-ethanolamine (DSPC) lipids with various concentrations of cholesterol (from 0 to 44 mol %). The passive release of encapsulated fluorescein was first characterized. It was observed to be higher when the membrane is in a fluid phase and increased with temperature but decreased upon addition of cholesterol. Next, the release of fluorescein was measured at different acoustic frequencies (0.8, 1.1, and 3.3 MHz) and peak-to-peak pressures (0, 2, 2.5, 5, and 8 MPa). Measurements were performed at temperatures where DOPC and DSPC liposomes were, respectively, in the fluid or gel phase. We found that the release rate did not depend on the ultrasound frequency. For DOPC liposomes, the ultrasound-triggered release of fluorescein decreased with increasing concentration of cholesterol in liposomes, while the behavior was more complex for DSPC liposomes. Overall, the triggered release from DSPC liposomes was up to ten times less than DOPC liposomes. Molecular dynamics simulations performed on a pure DOPC membrane showed that a membrane experiences, under a directional pressure of ±2.4 MPa, various changes in properties such as the area per lipid (APL). An increase in the APL was notably observed when the simulation box was laterally stretched or perpendicularly compressed, which was accompanied by an increase in the number of water molecules crossing the membrane. This suggests that ultrasound most probably enhances the diffusion of encapsulated molecules at small acoustic pressures by increasing the distance between lipids.
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Affiliation(s)
- Fatima El Hajj
- Sorbonne Université, CNRS, INSERM, Laboratoire d'Imagerie Biomédicale, LIB, F-75006 Paris, France
- Faculté des Sciences, Université Libanaise, Hadath 1003, Liban
| | - Patrick F J Fuchs
- Université de Paris, UFR Sciences du Vivant, F-75013 Paris, France
- Sorbonne Université, Ecole Normale Supérieure, PSL Research University, CNRS, Laboratoire des Biomolécules (LBM), F-75005 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
| | | | - Salah Hamieh
- Faculté des Sciences, Université Libanaise, Hadath 1003, Liban
| | - Nicolas Taulier
- Sorbonne Université, CNRS, INSERM, Laboratoire d'Imagerie Biomédicale, LIB, F-75006 Paris, France
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9
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Zhang Y, Li Q, Dong M, Han X. Effect of cholesterol on the fluidity of supported lipid bilayers. Colloids Surf B Biointerfaces 2020; 196:111353. [DOI: 10.1016/j.colsurfb.2020.111353] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/21/2020] [Accepted: 08/24/2020] [Indexed: 01/12/2023]
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10
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Kamble S, Patil S, Kulkarni M, Appala VRM. Interleaflet Decoupling in a Lipid Bilayer at Excess Cholesterol Probed by Spectroscopic Ellipsometry and Simulations. J Membr Biol 2020; 253:647-659. [PMID: 33221946 DOI: 10.1007/s00232-020-00156-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 11/11/2020] [Indexed: 11/26/2022]
Abstract
Artificial lipid membranes are often investigated as a replica of the cell membrane in the form of supported lipid bilayers (SLBs). In SLBs, the phase state of a lipid bilayer strongly depends on the presence of molecules such as cholesterol, ceramide, and physical parameters such as temperature. Cholesterol is a key molecule of biological membranes and it exerts condensing effect on lipid bilayers. In this paper, we demonstrate the influence of excess cholesterol content on a supported lipid bilayer of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) (fluid-phase) using spectroscopic ellipsometry (SE) and coarse-grained (CG) molecular dynamics (MD) simulations. The results show the condensation effect due to cholesterol addition up to 30% and interleaflet decoupling at excess cholesterol beyond 30%. SE results show the separation of individual leaflets of the bilayer and influence of cholesterol on the biophysical properties such as thickness and optical index. CG simulations were performed at different ratios of DOPC:cholesterol mixtures to explore cholesterol-driven bilayer properties and stability. The simulations displayed the accumulation of cholesterol molecules at the interface of the lower and upper leaflets of the bilayer, thus leading to undulations in the bilayer. This work reports the successful application of SE technique to study lipid-cholesterol interactions for the first time.
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Affiliation(s)
- Sagar Kamble
- Department of Applied Physics, Defence Institute of Advanced Technology (DIAT) DU, Girinagar, Pune, India
| | - Snehal Patil
- Department of Applied Physics, Defence Institute of Advanced Technology (DIAT) DU, Girinagar, Pune, India
| | - Mandar Kulkarni
- Division of Biophysical Chemistry, Chemical Center, Lund University, 22100, Lund, Sweden.
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11
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Frias MA, Disalvo EA. Breakdown of classical paradigms in relation to membrane structure and functions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183512. [PMID: 33202248 DOI: 10.1016/j.bbamem.2020.183512] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 01/10/2023]
Abstract
Updates of the mosaic fluid membrane model implicitly sustain the paradigms that bilayers are closed systems conserving a state of fluidity and behaving as a dielectric slab. All of them are a consequence of disregarding water as part of the membrane structure and its essential role in the thermodynamics and kinetics of membrane response to bioeffectors. A correlation of the thermodynamic properties with the structural features of water makes possible to introduce the lipid membrane as a responsive structure due to the relaxation of water rearrangements in the kinetics of bioeffectors' interactions. This analysis concludes that the lipid membranes are open systems and, according to thermodynamic of irreversible formalism, bilayers and monolayers can be reasonable compared under controlled conditions. The inclusion of water in the complex structure makes feasible to reconsider the concept of dielectric slab and fluidity.
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Affiliation(s)
- M A Frias
- Applied Biophysics and Food Research Center, CIBAAL-UNSE-CONICET, Santiago del Estero, Argentina
| | - E A Disalvo
- Applied Biophysics and Food Research Center, CIBAAL-UNSE-CONICET, Santiago del Estero, Argentina.
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12
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El-Beyrouthy J, Makhoul-Mansour MM, Taylor G, Sarles SA, Freeman EC. A new approach for investigating the response of lipid membranes to electrocompression by coupling droplet mechanics and membrane biophysics. J R Soc Interface 2019; 16:20190652. [PMID: 31822221 DOI: 10.1098/rsif.2019.0652] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
A new method for quantifying lipid-lipid interactions within biomimetic membranes undergoing electrocompression is demonstrated by coupling droplet mechanics and membrane biophysics. The membrane properties are varied by altering the lipid packing through the introduction of cholesterol. Pendant drop tensiometry is used to measure the lipid monolayer tension at an oil-water interface. Next, two lipid-coated aqueous droplets are manipulated into contact to form a bilayer membrane at their adhered interface. The droplet geometries are captured from two angles to provide accurate measurements of both the membrane area and the contact angle between the adhered droplets. Combining the monolayer tension and contact angle measurements enables estimations of the membrane tension with respect to lipid composition. Then, the membrane is electromechanically compressed using a transmembrane voltage. Electrostatic pressure, membrane tension and the work necessary for bilayer thinning are tracked, and a model is proposed to capture the mechanics of membrane compression. The results highlight that a previously unaccounted for energetic term is produced during compression, potentially reflecting changes in the lateral membrane structure. This residual energy is eliminated in cases with cholesterol mole fractions of 0.2 and higher, suggesting that cholesterol diminishes these adjustments.
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Affiliation(s)
- Joyce El-Beyrouthy
- School of Environmental, Civil, Agricultural, and Mechanical Engineering, The University of Georgia, Athens, GA 30602, USA
| | - Michelle M Makhoul-Mansour
- School of Environmental, Civil, Agricultural, and Mechanical Engineering, The University of Georgia, Athens, GA 30602, USA
| | - Graham Taylor
- Department of Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee, Knoxville, TN 37996, USA.,The Bredesen Center for Interdisciplinary Research, The University of Tennessee, Knoxville, TN 37996, USA
| | - Stephen A Sarles
- Department of Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee, Knoxville, TN 37996, USA
| | - Eric C Freeman
- School of Environmental, Civil, Agricultural, and Mechanical Engineering, The University of Georgia, Athens, GA 30602, USA
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13
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Patel J, Chowdhury EA, Noorani B, Bickel U, Huang J. Isoflurane increases cell membrane fluidity significantly at clinical concentrations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1862:183140. [PMID: 31790694 DOI: 10.1016/j.bbamem.2019.183140] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 11/18/2019] [Accepted: 11/27/2019] [Indexed: 01/17/2023]
Abstract
There is an on-going debate whether anesthetic drugs, such as isoflurane, can cause meaningful structural changes in cell membranes at clinical concentrations. In this study, the effects of isoflurane on lipid membrane fluidity were investigated using fluorescence anisotropy and spectroscopy. In order to get a complete picture, four very different membrane systems (erythrocyte ghosts, a 5-lipid mixture that mimics brain endothelial cell membrane, POPC/Chol, and pure DPPC) were selected for the study. In all four systems, we found that fluorescence anisotropies of DPH-PC, nile-red, and TMA-DPH decrease significantly at the isoflurane concentrations of 1 mM and 5 mM. Furthermore, the excimer/monomer (E/M) ratio of dipyrene-PC jumps immediately after the addition of isoflurane. We found that isoflurane is quite effective to loosen up highly ordered lipid domains with saturated lipids. Interestingly, 1 mM isoflurane causes a larger decrease of nile-red fluorescence anisotropy in erythrocyte ghosts than 52.2 mM of ethanol, which is three times the legal limit of blood alcohol level. Our results paint a consistent picture that isoflurane at clinical concentrations causes significant and immediate increase of membrane fluidity in a wide range of membrane systems.
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Affiliation(s)
- Jigesh Patel
- Department of Physics and Astronomy, Texas Tech University, Lubbock, TX 79409, United States of America
| | - Ekram A Chowdhury
- Department of Pharmaceutical Sciences, Texas Tech University Health Science Center, Amarillo, TX 79106, United States of America
| | - Behnam Noorani
- Department of Pharmaceutical Sciences, Texas Tech University Health Science Center, Amarillo, TX 79106, United States of America
| | - Ulrich Bickel
- Department of Pharmaceutical Sciences, Texas Tech University Health Science Center, Amarillo, TX 79106, United States of America
| | - Juyang Huang
- Department of Physics and Astronomy, Texas Tech University, Lubbock, TX 79409, United States of America.
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14
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Kulkarni JA, Witzigmann D, Leung J, Tam YYC, Cullis PR. On the role of helper lipids in lipid nanoparticle formulations of siRNA. NANOSCALE 2019; 11:21733-21739. [PMID: 31713568 DOI: 10.1039/c9nr09347h] [Citation(s) in RCA: 168] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Onpattro, the first RNAi-based therapeutic to receive FDA approval, is enabled by a lipid nanoparticle (LNP) system that facilitates siRNA delivery into the cytoplasm of target cells (hepatocytes) following intravenous (i.v.) administration. These LNP-siRNA systems consist of four lipid components (ionizable cationic lipid, distearolyphosphatidycholine or DSPC, cholesterol, and PEG-lipid) and siRNA. The ionizable cationic lipid has been optimised for RNA encapsulation and intracellular delivery, and the PEG-lipids have been engineered to regulate LNP size and transfection potency. The roles of the other "helper" lipids, DSPC and cholesterol, remain less clear. Here we show that in empty LNP systems that do not contain siRNA, DSPC-cholesterol resides in outer layers, whereas in loaded systems a portion of the DSPC-cholesterol is internalised together with siRNA. It is concluded that the presence of internalised helper lipid is vital to the stable encapsulation of siRNA in the LNP and thus to LNP-siRNA function.
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Affiliation(s)
- Jayesh A Kulkarni
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, CanadaV6T 1Z3.
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15
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Andrade S, Ramalho MJ, Loureiro JA, Pereira MC. Interaction of natural compounds with biomembrane models: A biophysical approach for the Alzheimer's disease therapy. Colloids Surf B Biointerfaces 2019; 180:83-92. [PMID: 31030024 DOI: 10.1016/j.colsurfb.2019.04.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/05/2019] [Accepted: 04/09/2019] [Indexed: 11/29/2022]
Abstract
Natural compounds such as caffeine (CA), gallic acid (GA) and tannic acid (TA) have been reported to be useful for Alzheimer's disease (AD) therapy. It was proved that some natural compounds inhibit the formation of senil plaques composed by beta-amyloid peptide (Aβ), a hallmark of AD. Evidences suggest that the therapeutic activity of compounds depends of their interaction with biological membranes. To understand why these compounds fail in vivo and in clinical trials, it is important to evaluate their pharmacokinetics properties. Thus, a biophysical approach to study drug-membrane interactions is essential to understand the mechanisms by which the drugs interact with the cellular membranes and affect the Aβ production, aggregation and clearance pathways. 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and cholesterol (chol) were used to mimic the biophysical properties of cell membranes and study their interactions with these compounds. The partition coefficient, influence on membrane fluidity and location within the bilayer of the drugs were studied by derivative spectrophotometry, dynamic light scattering and fluorescence quenching, respectively. The results suggest that TA exhibited a significant higher partition than CA and GA and a preferential location near to the polar head of bilayer. The obtained results may explain the therapeutic mechanisms reported for these natural compounds.
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Affiliation(s)
- Stephanie Andrade
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
| | - Maria J Ramalho
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
| | - Joana A Loureiro
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
| | - Maria Carmo Pereira
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
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16
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Meinhardt S, Schmid F. Structure of lateral heterogeneities in a coarse-grained model for multicomponent membranes. SOFT MATTER 2019; 15:1942-1952. [PMID: 30662989 DOI: 10.1039/c8sm02261e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We study the lateral domain structure in a coarse-grained molecular model for multicomponent lipid bilayers by semi-grandcanonical Monte Carlo simulations. The membranes are filled with liquid ordered (lo) domains surrounded by a liquid disordered (ld) matrix. Depending on the membrane composition and temperature, we identify different morphological regimes: one regime (I) where the lo domains are small and relatively compact, and two regimes (II, II') where they are larger and often interconnected. In the latter two regimes, the ld matrix forms a network of disordered trenches separating the lo domains, with a relatively high content of interdigitated line defects. Since such defects are also a structural element of the modulated ripple phase in one component membranes, we argue that the regimes II, II' may be amorphous equivalents of the ripple phase in multicomponent membranes. We also analyze the local structure and provide evidence that the domains in regime I are stabilized by a monolayer curvature mechanism postulated in earlier work [S. Meinhardt et al., PNAS, 2013, 110, 4476].
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Affiliation(s)
- Sebastian Meinhardt
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, USA
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17
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Effect of Cholesterol on the Dipole Potential of Lipid Membranes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1115:135-154. [DOI: 10.1007/978-3-030-04278-3_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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18
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Pantelopulos GA, Straub JE. Regimes of Complex Lipid Bilayer Phases Induced by Cholesterol Concentration in MD Simulation. Biophys J 2018; 115:2167-2178. [PMID: 30414630 DOI: 10.1016/j.bpj.2018.10.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 10/11/2018] [Accepted: 10/16/2018] [Indexed: 01/06/2023] Open
Abstract
Cholesterol is essential to the formation of phase-separated lipid domains in membranes. Lipid domains can exist in different thermodynamic phases depending on the molecular composition and play significant roles in determining structure and function of membrane proteins. We investigate the role of cholesterol in the structure and dynamics of ternary lipid mixtures displaying phase separation using molecular dynamics simulations, employing a physiologically relevant span of cholesterol concentration. We find that cholesterol can induce formation of three regimes of phase behavior: 1) miscible liquid-disordered bulk, 2) phase-separated, domain-registered coexistence of liquid-disordered and liquid-ordered domains, and 3) phase-separated, domain-antiregistered coexistence of liquid-disordered and newly identified nanoscopic gel domains composed of cholesterol threads we name "cholesterolic gel" domains. These findings are validated and discussed in the context of current experimental knowledge, models of cholesterol spatial distributions, and models of ternary lipid-mixture phase separation.
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Affiliation(s)
| | - John E Straub
- Department of Chemistry, Boston University, Boston, Massachusetts.
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19
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Miller EJ, Voïtchovsky K, Staykova M. Substrate-led cholesterol extraction from supported lipid membranes. NANOSCALE 2018; 10:16332-16342. [PMID: 30132496 DOI: 10.1039/c8nr03399d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The lipid membrane is a principal building block in biology, technology and industry, where it often occurs supported by other hydrophilic structures. Interactions with the support can affect the physical behavior of the membrane from the local organization and diffusion of lipids and proteins, to phase transitions, and the local mechanical properties. In this study we show that supporting substrates textured with nanoscale hydrophilic and hydrophobic domains can modify the membrane's chemical composition by selectively extracting cholesterol molecules without affecting the remaining phospholipids. Using polydimethylsiloxane (PDMS) substrates with various degrees of plasma oxidation, we are able to trigger dramatic changes in the membrane morphology and biophysical properties, and relate them to the amount of extracted cholesterol. We also show that it is possible to control the cholesterol extraction through mechanical extension of the flexible PDMS support. Given the ubiquity of bio-substrates with textured surface properties and the wide use of PDMS we expect that our results will have implications not only in biological and chemical sciences but also in nanotechnologies such as organ on a chip technologies, biosensors, and stretchable bio-electronics.
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20
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Sarangi NK, Roobala C, Basu JK. Unraveling complex nanoscale lipid dynamics in simple model biomembranes: Insights from fluorescence correlation spectroscopy in super-resolution stimulated emission depletion mode. Methods 2018; 140-141:198-211. [DOI: 10.1016/j.ymeth.2017.11.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 11/18/2017] [Accepted: 11/19/2017] [Indexed: 12/24/2022] Open
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21
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Ferraro NA, Cascio M. Cross-Linking-Mass Spectrometry Studies of Cholesterol Interactions with Human α1 Glycine Receptor. Anal Chem 2018; 90:2508-2516. [DOI: 10.1021/acs.analchem.7b03639] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Nicholas A. Ferraro
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, Pennsylvania 15282, United States
| | - Michael Cascio
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, Pennsylvania 15282, United States
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22
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Shaghaghi M, Keyvanloo A, Huang Z, Szoka FC, Thewalt JL. Constrained Versus Free Cholesterol in DPPC Membranes: A Comparison of Chain Ordering Ability Using Deuterium NMR. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:14405-14413. [PMID: 29120186 DOI: 10.1021/acs.langmuir.7b03299] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report here the first exploration of the nature of the hydrophobic region of bilayer membranes formed from sterol-modified phospholipids [Huang, Z.; Szoka, F. C., Sterol-Modified Phospholipids: Cholesterol and Phospholipid Chimeras with Improved Biomembrane Properties. J. Am. Chem. Soc. 2008, 130 (46), 15702-15712] & [Ding, J.; Starling, A. P.; East, J. M.; Lee, A. G., Binding Sites for Cholesterol on Ca(2+)-ATPase Studied by Using a Cholesterol-Containing Phospholipid. Biochemistry 1994, 33 (16), 4974-4979]. Using 2H NMR spectroscopy, we present our results for the phase behavior and acyl chain ordering of multilamellar vesicles (MLVs) of a sterol-modified phospholipid, 1-cholesterylhemisuccinoyl-2-palmitoyl(d31)-sn-glycero-3-phosphocholine (hereafter referred to as CholPPC-d31). We compared our results with the conformational order induced by cholesterol at various concentrations in 1-palmitoyl,2-palmitoyl(d31)-sn-glycero-3-phosphocholine (DPPC-d31)/cholesterol membranes. On the basis of the existing literature [Foglia, F.; Barlow, D. J.; Szoka, F. C.; Huang, Z.; Rogers, S. E.; Lawrence, M. J., Structural Studies of the Monolayers and Bilayers Formed by a Novel Cholesterol-Phospholipid Chimera. Langmuir 2011, 27 (13), 8275-8281], we expected to find that the deuterated palmitoyl chain in CholPPC-d31 membranes had an order parameter profile similar to the deuterated palmitoyl chain of sn-2 labeled DPPC-d31 in MLVs of a mixture of DPPC-d31 with 40 mol % unconstrained cholesterol. Our data indicate that the ordering ability of cholesterol in CholPPC is significantly reduced compared to free cholesterol in DPPC. This result emphasizes that cholesterol molecules must be free to move in the bilayers to reach their maximum ordering ability. In other words, when compared to unconstrained cholesterol, the constrained cholesterol moiety in CholPPC causes nonoptimal chain packing.
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Affiliation(s)
| | | | - Zhaohua Huang
- Merrimack Pharmaceuticals , One Kendall Square, Suite B7201, Cambridge, Massachusetts 02139, United States
| | - Francis C Szoka
- Department of Bioengineering and Therapeutic Sciences, School of Pharmacy, University of California , San Francisco, California 94143, United States
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23
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Sarangi NK, Ayappa KG, Basu JK. Complex dynamics at the nanoscale in simple biomembranes. Sci Rep 2017; 7:11173. [PMID: 28894156 PMCID: PMC5593986 DOI: 10.1038/s41598-017-11068-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 07/28/2017] [Indexed: 11/25/2022] Open
Abstract
Nature is known to engineer complex compositional and dynamical platforms in biological membranes. Understanding this complex landscape requires techniques to simultaneously detect membrane re-organization and dynamics at the nanoscale. Using super-resolution stimulated emission depletion (STED) microscopy coupled with fluorescence correlation spectroscopy (FCS), we reveal direct experimental evidence of dynamic heterogeneity at the nanoscale in binary phospholipid-cholesterol bilayers. Domain formation on the length scale of ~200–600 nm due to local cholesterol compositional heterogeneity is found to be more prominent at high cholesterol content giving rise to distinct intra-domain lipid dynamics. STED-FCS reveals unique dynamical crossover phenomena at length scales of ~100–150 nm within each of these macroscopic regions. The extent of dynamic heterogeneity due to intra-domain hindered lipid diffusion as reflected from the crossover length scale, is driven by cholesterol packing and organization, uniquely influenced by phospholipid type. These results on simple binary model bilayer systems provide novel insights into pathways leading to the emergence of complex nanodomain substructures with implications for a wide variety of membrane mediated cellular events.
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Affiliation(s)
- Nirod Kumar Sarangi
- Department of Physics, Indian Institute of Science, Bangalore, 560 012, India
| | - K G Ayappa
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, 560 012, India. .,Center for Biosystems Science and Engineering, Indian Institute of Science, Bangalore, 560 012, India.
| | - Jaydeep Kumar Basu
- Department of Physics, Indian Institute of Science, Bangalore, 560 012, India.
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24
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Giri RP, Chakrabarti A, Mukhopadhyay MK. Cholesterol-Induced Structural Changes in Saturated Phospholipid Model Membranes Revealed through X-ray Scattering Technique. J Phys Chem B 2017; 121:4081-4090. [DOI: 10.1021/acs.jpcb.6b12587] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Rajendra P. Giri
- Saha Institute of Nuclear Physics, HBNI, 1/AF, Bidhannagar, Kolkata 700064, India
| | - Abhijit Chakrabarti
- Saha Institute of Nuclear Physics, HBNI, 1/AF, Bidhannagar, Kolkata 700064, India
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25
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26
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Sarangi NK, P II, Ayappa KG, Visweswariah SS, Basu JK. Super-resolution Stimulated Emission Depletion-Fluorescence Correlation Spectroscopy Reveals Nanoscale Membrane Reorganization Induced by Pore-Forming Proteins. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:9649-57. [PMID: 27564541 DOI: 10.1021/acs.langmuir.6b01848] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Membrane-protein interactions play a central role in membrane mediated cellular processes ranging from signaling, budding, and fusion, to transport across the cell membrane. Of particular significance is the process of efficient protein olgomerization and transmembrane pore formation on the membrane surface; the primary virulent pathway for the action of antimicrobial peptides and pore forming toxins (PFTs). The suggested nanoscopic length scales and dynamic nature of such membrane lipid-protein interactions makes their detection extremely challenging. Using a combination of super-resolution stimulated emission depletion nanoscopy with fluorescence correlation spectroscopy (STED-FCS) we unravel the emergence of nanoscale lateral heterogeneity in supported bilayer membranes made up of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and cholesterol upon interaction with the PFT, listeriolysin O (LLO). A distinct length scale-dependent dynamical crossover (<200 nm) from a Brownian diffusive regime is observed at 33 and 50% cholesterol compositions, indicating the partitioning of lipids into domains with variable cholesterol content. At 25% cholesterol content, this dyamical crossover is observed only in bilayers incubated with LLO providing evidence for the existence of sub ∼100 nm dynamical lipid nanodomains bound to LLO pore assemblies. By introducing asymmetry in cholesterol composition across the bilayer leaflets we infer that this domain formation is driven largely due to active cholesterol sequestration and transient trapping of lipids to the membrane bound motifs present in the toxins, en route to LLO oligomerization and subsequent pore formation. Bilayers prepared with labeled lipids present in either the proximal or distal leaflet allow us to track the dynamical perturbation in a leaflet-dependent manner upon LLO incubation. From the differences in the extent and intensity of the dynamical crossover as observed with STED-FCS, these experiments reveal that the affinity for cholesterol in the membrane binding motifs of the LLO subdomains induce cholesterol and lipid reorganization to a greater extent in the distal (upper) leaflet when compared with the proximal (lower) leaflet. The observed length scale-dependent membrane reorganization that occurs due to invasion by LLO could be generalized to other cholesterol-dependent cytolysins and emphasizes the significant advantage of using super-resolution STED nanoscopy to unravel complex lipid-protein interactions in membrane and cellular biophysics.
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Affiliation(s)
- Nirod Kumar Sarangi
- Department of Physics, ‡Center for Biosystems Science and Engineering, ¶Department of Chemical Engineering, and §Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science Bangalore 560 012, India
| | - Ilanila I P
- Department of Physics, ‡Center for Biosystems Science and Engineering, ¶Department of Chemical Engineering, and §Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science Bangalore 560 012, India
| | - K G Ayappa
- Department of Physics, ‡Center for Biosystems Science and Engineering, ¶Department of Chemical Engineering, and §Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science Bangalore 560 012, India
| | - Sandhya S Visweswariah
- Department of Physics, ‡Center for Biosystems Science and Engineering, ¶Department of Chemical Engineering, and §Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science Bangalore 560 012, India
| | - Jaydeep Kumar Basu
- Department of Physics, ‡Center for Biosystems Science and Engineering, ¶Department of Chemical Engineering, and §Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science Bangalore 560 012, India
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27
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Lor C, Hirst LS. Effects of Low Concentrations of Docosahexaenoic Acid on the Structure and Phase Behavior of Model Lipid Membranes. MEMBRANES 2015; 5:857-74. [PMID: 26690231 PMCID: PMC4704016 DOI: 10.3390/membranes5040857] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 11/25/2015] [Indexed: 11/21/2022]
Abstract
In this paper we report an X-ray diffraction study on the phase behavior of binary lipid mixtures of 1-palmitoyl-2-docosahexaenoyl-sn-glycero-3-phosphoethanolamine (DHA-PE) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) at low concentrations below 5.0 mol% DHA-PE. Our results show that DHA-PE induces phase separation into a DHA rich liquid crystalline (Lα) phase and a DHA poor gel (Lβ') phase at overall DHA-PE concentrations as low as 0.1 mol%. In addition, we find that the structure of the Lβ' phase, from which the DHA-PE molecules are largely excluded, is modified in the phase-separated state at low DHA-PE concentrations, with a decrease in bilayer thickness of 1.34 nm for 0.1 mol% at room temperature, compared to pure DPPC bilayers. This result is contrary to that seen in similar studies on mono-unsaturated lipids where an increase in bilayer thickness is observed. The surprising effect of such low DHA-PE concentrations on membrane structure may be important in understanding the role of highly polyunsaturated lipids in biological membrane-based structures and similar artificial surfactant systems.
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Affiliation(s)
- Chai Lor
- Bioengineering and Small Scale Technologies, School of Engineering, University of California, Merced, CA 95343, USA.
| | - Linda S Hirst
- Department of Physics, School of Natural Sciences, University of California, Merced, CA 95343, USA.
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28
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Alwarawrah M, Hussain F, Huang J. Alteration of lipid membrane structure and dynamics by diacylglycerols with unsaturated chains. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:253-63. [PMID: 26607007 DOI: 10.1016/j.bbamem.2015.11.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 11/05/2015] [Accepted: 11/18/2015] [Indexed: 01/15/2023]
Abstract
Diacylglycerols (DAGs) with unsaturated acyl chains play many important roles in biomembranes, such as a second messenger and activator for protein kinase C. In this study, three DAGs of distinctly different chain unsaturations (i.e. di16:0DAG (DPG), 16:0-18:1DAG (POG), and di18:1DAG (DOG)) are studied using atomistic MD simulation to compare their roles in the structure and dynamics of 16:0-18:1phosphatidylcholine (POPC) membranes. All three DAGs are able to produce the so-called 'condensing effect' in POPC membranes: decreasing area-per-lipid, and increasing acyl chain order and bilayer thickness. Our visual and quantitative analyses clearly show that DAG with unsaturated chains induce larger spacing between POPC headgroups, compared with DAG with saturated chains; this particular effect has long been hypothesized to be crucial for activating enzymes and receptors in cell membranes. DAGs with unsaturated chains are also located closer to the bilayer/aqueous interface than DPG and are more effective in slowing down lateral diffusion of molecules. We show that DAG molecules seek the "umbrella coverage" from neighboring phospholipid headgroups - similar to cholesterol. Unlike cholesterol, DAGs also hide their chains from water by laterally inserting their chains into the surrounding. Thus, acyl chains of DAG are more spread and disordered than those of PC due to the insertion. By calculating the potential of mean force (PMF) for POPC in POPC/DAG bilayers, we found that all three DAGs can significantly increase the free energy barrier for POPC to flip-flop, but only DAGs with unsaturated chains can additionally increase the free energy of POPC desorption.
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Affiliation(s)
- Mohammad Alwarawrah
- Department of Physics, Texas Tech University, Lubbock, TX 79409, United States
| | - Fazle Hussain
- Department of Mechanical Engineering, Texas Tech University, Lubbock, TX 79409, United States
| | - Juyang Huang
- Department of Physics, Texas Tech University, Lubbock, TX 79409, United States.
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29
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Neves AR, Nunes C, Reis S. Resveratrol induces ordered domains formation in biomembranes: Implication for its pleiotropic action. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:12-8. [PMID: 26456556 DOI: 10.1016/j.bbamem.2015.10.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Revised: 10/05/2015] [Accepted: 10/07/2015] [Indexed: 12/17/2022]
Abstract
Resveratrol is a polyphenol compound with great value in cancer therapy, cardiovascular protection, and neurodegenerative disorders. The mechanism by which resveratrol exerts such pleiotropic effects is not yet clear and there is a huge need to understand the influence of this compound on the regulation of lipid domains formation on membrane structure. The aim of the present study was to reveal potential molecular interactions between resveratrol and lipid rafts found in cell membranes by means of Förster resonance energy transfer, DPH fluorescence quenching, and triton X-100 detergent resistance assay. Liposomes composed of egg phosphatidylcholine, cholesterol, and sphingomyelin were used as model membranes. The results revealed that resveratrol induces phase separation and formation of liquid-ordered domains in bilayer structures. The formation of such tightly packed lipid rafts is important for different signal transduction pathways, through the regulation of membrane-associating proteins, that can justify several pharmacological activities of this compound.
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Affiliation(s)
- Ana Rute Neves
- UCIBIO, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Cláudia Nunes
- UCIBIO, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Salette Reis
- UCIBIO, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
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30
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Matyszewska D, Brzezińska K, Juhaniewicz J, Bilewicz R. pH dependence of daunorubicin interactions with model DMPC:Cholesterol membranes. Colloids Surf B Biointerfaces 2015. [DOI: 10.1016/j.colsurfb.2015.07.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Daswani VP, Ayesa U, Venegas B, Chong PLG. Concentration-Induced J-Aggregate Formation Causes a Biphasic Change in the Release of trans-Combretastatin A4 Disodium Phosphate from Archaeosomes and the Subsequent Cytotoxicity on Mammary Cancer Cells. Mol Pharm 2015; 12:3724-34. [DOI: 10.1021/acs.molpharmaceut.5b00500] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Varsha P. Daswani
- Department of Medical Genetics
and Molecular Biochemistry, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, United States
| | - Umme Ayesa
- Department of Medical Genetics
and Molecular Biochemistry, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, United States
| | - Berenice Venegas
- Department of Medical Genetics
and Molecular Biochemistry, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, United States
| | - Parkson Lee-Gau Chong
- Department of Medical Genetics
and Molecular Biochemistry, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, United States
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32
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Neves AR, Nunes C, Reis S. New Insights on the Biophysical Interaction of Resveratrol with Biomembrane Models: Relevance for Its Biological Effects. J Phys Chem B 2015; 119:11664-72. [PMID: 26237152 DOI: 10.1021/acs.jpcb.5b05419] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Resveratrol has been widely studied because of its pleiotropic effects in cancer therapy, neuroprotection, and cardioprotection. It is believed that the interaction of resveratrol with biological membranes may play a key role in its therapeutic activity. The capacity of resveratrol to partition into lipid bilayers, its possible location within the membrane, and the influence of this compound on the membrane fluidity were investigated using membrane mimetic systems composed of egg l-α-phosphatidylcholine (EPC), cholesterol (CHOL), and sphingomyelin (SM). The results showed that resveratrol has greater affinity for the EPC bilayers than for EPC:CHOL [4:1] and EPC:CHOL:SM [1:1:1] membrane models. The increased difficulty in penetrating tight packed membranes is also demonstrated by fluorescence quenching of probes and by fluorescence anisotropy measurements. Resveratrol may be involved in the regulation of cell membrane fluidity, thereby contributing for cell homeostasis.
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Affiliation(s)
- Ana Rute Neves
- UCIBIO, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto , Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Cláudia Nunes
- UCIBIO, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto , Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Salette Reis
- UCIBIO, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto , Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
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33
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Jurak M, Chibowski E. Characteristics of a phospholipid DOPC/cholesterol bilayer based on surface free energy and its components. RSC Adv 2015. [DOI: 10.1039/c5ra08203j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The effect of the cholesterol (Chol) content (xChol = 0.25; 0.5; 0.75) on the wettability changes of solid supported bilayers of unsaturated 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) was investigated at 20 °C and 37 °C.
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Affiliation(s)
- M. Jurak
- Department of Physical Chemistry
- Faculty of Chemistry
- Maria Curie-Skłodowska University
- 20-031 Lublin
- Poland
| | - E. Chibowski
- Department of Physical Chemistry
- Faculty of Chemistry
- Maria Curie-Skłodowska University
- 20-031 Lublin
- Poland
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34
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Surface Gibbs energy interaction of phospholipid/cholesterol monolayers deposited on mica with probe liquids. Chem Phys Lipids 2014; 183:60-7. [DOI: 10.1016/j.chemphyslip.2014.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 05/20/2014] [Accepted: 05/21/2014] [Indexed: 12/22/2022]
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35
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Qian S, Rai D, Heller WT. Alamethicin Disrupts the Cholesterol Distribution in Dimyristoyl Phosphatidylcholine–Cholesterol Lipid Bilayers. J Phys Chem B 2014; 118:11200-8. [DOI: 10.1021/jp504886u] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Shuo Qian
- Center for Structural Molecular Biology and ‡Biology and Soft Matter Division; Oak Ridge National Laboratory; P.O. Box 2008, MS-6473; Oak Ridge, Tennessee 37831, United States
| | - Durgesh Rai
- Center for Structural Molecular Biology and ‡Biology and Soft Matter Division; Oak Ridge National Laboratory; P.O. Box 2008, MS-6473; Oak Ridge, Tennessee 37831, United States
| | - William T. Heller
- Center for Structural Molecular Biology and ‡Biology and Soft Matter Division; Oak Ridge National Laboratory; P.O. Box 2008, MS-6473; Oak Ridge, Tennessee 37831, United States
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36
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Anikeeva N, Sykulev Y, Delikatny EJ, Popov AV. Core-based lipid nanoparticles as a nanoplatform for delivery of near-infrared fluorescent imaging agents. AMERICAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 2014; 4:507-524. [PMID: 25250201 PMCID: PMC4171838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 08/06/2014] [Indexed: 06/03/2023]
Abstract
Pyropheophorbide a (Pyro) is a near-infrared (NIR) fluorescent dye and photosensitizer with high quantum yield that makes the dye suitable for tumor treatment both as an imaging and therapy agent. We have designed and synthesized a series of a Pyro-based NIR probes, based on the conjugation of Pyro with lipids. The nature of our probes requires the use of a lipophilic carrier to deliver the probes to cancer cell membranes. To address this, we have utilized lipid-based nanoparticles (LNPs) consisting of PEGylated lipids, which form the nanoparticle shell, and a lipid core. To endow the LNPs with targeting properties, nitrilotriacetic acid (NTA) lipids were included in the composition that enables the non-covalent attachment of His-tag targeting proteins preserving their functional activity. We found that the nature of the core molecules influence the nanoparticle size, shelf-life and stability at physiological temperature. Two different Pyro-lipid conjugates were loaded either into the core or shell of the LNPs. The conjugates revealed differential ability to be accumulated in the cell membrane of the target cells with time. Thus, the modular organization of the core-shell LNPs allows facile adjustment of their composition with goal to fine tuning the nanoparticle properties for in vivo application.
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Affiliation(s)
- Nadia Anikeeva
- Department of Microbiology and Immunology and Kimmel Cancer Center, Thomas Jefferson UniversityPhiladelphia, Pennsylvania, USA
| | - Yuri Sykulev
- Department of Microbiology and Immunology and Kimmel Cancer Center, Thomas Jefferson UniversityPhiladelphia, Pennsylvania, USA
| | - Edward J Delikatny
- Department of Radiology, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, Pennsylvania, USA
| | - Anatoliy V Popov
- Department of Radiology, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, Pennsylvania, USA
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37
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Lorent J, Lins L, Domenech Ò, Quetin-Leclercq J, Brasseur R, Mingeot-Leclercq MP. Domain formation and permeabilization induced by the saponin α-hederin and its aglycone hederagenin in a cholesterol-containing bilayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:4556-4569. [PMID: 24690040 DOI: 10.1021/la4049902] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Saponins and triterpenic acids have been shown to be able to interact with lipid membranes and domains enriched with cholesterol (rafts). How saponins are able to modulate lipid phase separation in membranes and the role of the sugar chains for this activity is unknown. We demonstrate in a binary membrane model composed of DMPC/Chol (3:1 mol/mol) that the saponin α-hederin and its aglycone presenting no sugar chain, the triterpenic acid hederagenin, are able to induce the formation of lipid domains. We show on multilamellar vesicles (MLV), giant unilamellar vesicles (GUV), and supported planar bilayers (SPB) that the presence of sugar units on the sapogenin accelerates domain formation and increases the proportion of sterols within these domains. The domain shape is also influenced by the presence of sugars because α-hederin and hederagenin induce the formation of tubular and spherical domains, respectively. These highly curved structures should result from the induction of membrane curvature by both compounds. In addition to the formation of domains, α-hederin and hederagenin permeabilize GUV. The formation of membrane holes by α-hederin comes along with the accumulation of lipids into nonbilayer structures in SPB. This process might be responsible for the permeabilizing activity of both compounds. In LUV, permeabilization by α-hederin was sterol-dependent. The biological implications of our results and the mechanisms involved are discussed in relation to the activity of saponins and triterpenic acids on membrane rafts, cancer cells, and hemolysis.
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Affiliation(s)
- Joseph Lorent
- Université Catholique de Louvain , Louvain Drug Research Institute, Cellular and Molecular Pharmacology, B1.73.05, Avenue E. Mounier 73, B-1200 Brussels, Belgium
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38
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Daily MD, Olsen BN, Schlesinger PH, Ory DS, Baker NA. Improved Coarse-Grained Modeling of Cholesterol-Containing Lipid Bilayers. J Chem Theory Comput 2014; 10:2137-2150. [PMID: 24910542 PMCID: PMC4044725 DOI: 10.1021/ct401028g] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cholesterol trafficking, which is an essential function in mammalian cells, is intimately connected to molecular-scale interactions through cholesterol modulation of membrane structure and dynamics and interaction with membrane receptors. Since these effects of cholesterol occur on micro- to millisecond timescales, it is essential to develop accurate coarse-grained simulation models that can reach these timescales. Cholesterol has been shown experimentally to thicken the membrane and increase phospholipid tail order between 0-40% cholesterol, above which these effects plateau or slightly decrease. Here, we showed that the published MARTINI coarse-grained force-field for phospholipid (POPC) and cholesterol fails to capture these effects. Using reference atomistic simulations, we systematically modified POPC and cholesterol bonded parameters in MARTINI to improve its performance. We showed that the corrections to pseudo-bond angles between glycerol and the lipid tails and around the oleoyl double bond particle (the "angle-corrected model") slightly improves the agreement of MARTINI with experimentally measured thermal, elastic, and dynamic properties of POPC membranes. The angle-corrected model improves prediction of the thickening and ordering effects up to 40% cholesterol but overestimates these effects at higher cholesterol concentration. In accordance with prior work that showed the cholesterol rough face methyl groups are important for limiting cholesterol self-association, we revised the coarse-grained representation of these methyl groups to better match cholesterol-cholesterol radial distribution functions from atomistic simulations. In addition, by using a finer-grained representation of the branched cholesterol tail than MARTINI, we improved predictions of lipid tail order and bilayer thickness across a wide range of concentrations. Finally, transferability testing shows that a model incorporating our revised parameters into DOPC outperforms other CG models in a DOPC/cholesterol simulation series, which further argues for its efficacy and generalizability. These results argue for the importance of systematic optimization for coarse-graining biologically important molecules like cholesterol with complicated molecular structure.
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Affiliation(s)
- Michael D Daily
- Computational and Statistical Analytics Division, Pacific Northwest National Laboratory, Richland, Washington
| | - Brett N Olsen
- Department of Medicine, Diabetic Cardiovascular Disease Center, Washington University School of Medicine, St. Louis, Missouri
| | - Paul H Schlesinger
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri
| | - Daniel S Ory
- Department of Medicine, Diabetic Cardiovascular Disease Center, Washington University School of Medicine, St. Louis, Missouri
| | - Nathan A Baker
- Computational and Statistical Analytics Division, Pacific Northwest National Laboratory, Richland, Washington
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39
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Pinheiro M, Pereira‐Leite C, Arêde M, Nunes C, Caio JM, Moiteiro C, Giner‐Casares JJ, Lúcio M, Brezesinski G, Camacho L, Reis S. Evaluation of the Structure–Activity Relationship of Rifabutin and Analogs: A Drug–Membrane Study. Chemphyschem 2013; 14:2808-16. [DOI: 10.1002/cphc.201300262] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Indexed: 01/15/2023]
Affiliation(s)
- Marina Pinheiro
- REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira n.° 228, 4050‐313 Porto (Portugal)
| | - Catarina Pereira‐Leite
- REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira n.° 228, 4050‐313 Porto (Portugal)
| | - Mariana Arêde
- REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira n.° 228, 4050‐313 Porto (Portugal)
| | - Cláudia Nunes
- REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira n.° 228, 4050‐313 Porto (Portugal)
| | - João M. Caio
- Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa (Portugal)
| | - Cristina Moiteiro
- Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa (Portugal)
| | - Juan J. Giner‐Casares
- Departamento de Química Física y Termodinámica, Universidad de Córdoba, España (Spain)
- Department of Interfaces, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476 Potsdam (Germany)
| | - Marlene Lúcio
- REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira n.° 228, 4050‐313 Porto (Portugal)
| | - Gerald Brezesinski
- Department of Interfaces, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476 Potsdam (Germany)
| | - Luis Camacho
- Departamento de Química Física y Termodinámica, Universidad de Córdoba, España (Spain)
| | - Salette Reis
- REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira n.° 228, 4050‐313 Porto (Portugal)
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40
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Pinheiro M, Arêde M, Nunes C, Caio JM, Moiteiro C, Lúcio M, Reis S. Differential Interactions of Rifabutin with Human and Bacterial Membranes: Implication for Its Therapeutic and Toxic Effects. J Med Chem 2013; 56:417-26. [DOI: 10.1021/jm301116j] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Marina Pinheiro
- REQUIMTE,
Departamento de Ciências
Químicas, Faculdade de Farmácia, Universidade do Porto,
Rua de Jorge Viterbo Ferreira no. 228, Porto 4050-313, Portugal
| | - Mariana Arêde
- REQUIMTE,
Departamento de Ciências
Químicas, Faculdade de Farmácia, Universidade do Porto,
Rua de Jorge Viterbo Ferreira no. 228, Porto 4050-313, Portugal
| | - Cláudia Nunes
- REQUIMTE,
Departamento de Ciências
Químicas, Faculdade de Farmácia, Universidade do Porto,
Rua de Jorge Viterbo Ferreira no. 228, Porto 4050-313, Portugal
| | - João M. Caio
- Centro de Química e Bioquímica,
Departamento de Química e Bioquímica, Faculdade de Ciências,
Universidade de Lisboa, Lisboa, Portugal
| | - Cristina Moiteiro
- Centro de Química e Bioquímica,
Departamento de Química e Bioquímica, Faculdade de Ciências,
Universidade de Lisboa, Lisboa, Portugal
| | - Marlene Lúcio
- REQUIMTE,
Departamento de Ciências
Químicas, Faculdade de Farmácia, Universidade do Porto,
Rua de Jorge Viterbo Ferreira no. 228, Porto 4050-313, Portugal
| | - Salette Reis
- REQUIMTE,
Departamento de Ciências
Químicas, Faculdade de Farmácia, Universidade do Porto,
Rua de Jorge Viterbo Ferreira no. 228, Porto 4050-313, Portugal
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41
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Peter Slotte J. Molecular properties of various structurally defined sphingomyelins -- correlation of structure with function. Prog Lipid Res 2013; 52:206-19. [PMID: 23295259 DOI: 10.1016/j.plipres.2012.12.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 12/20/2012] [Accepted: 12/21/2012] [Indexed: 01/10/2023]
Abstract
Sphingomyelins are important phospholipids in plasma membranes of most cells. Because of their dominantly saturated nature, they affect the lateral structure of membranes, and contribute to the regulation of cholesterol distribution within membranes, and in cells. However, the abundance of molecular species present in cells also implies that sphingomyelins have other, more specific functions. Many of these functions are currently unknown, but are under extensive study. Mostly model membrane studies have shown that sphingomyelins (and other sphingolipids), in contrast to glycerophospholipids, have important hydrogen bonding properties which in several important ways confer specific functional properties to this abundant class of membrane phospholipids. The often very asymmetric nature of sphingomyelins, arising from mismatch in length between the long chain base and N-acyl chains, also impose specific properties (e.g., interdigitation) to sphingomyelins not seen with glycerophospholipids. In this review, the latest sphingomyelin literature will be scrutinized, and an effort will be made to correlate the molecular structure of sphingomyelin with functional properties. In particular, the effects of head group properties, interfacial hydrogen bonding, long chain base hydroxylation, N-acyl chain hydroxylation, and N-acyl chain methyl-branching will be discussed.
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Affiliation(s)
- J Peter Slotte
- Biochemistry, Department of Biosciences, Åbo Akademi University, Tykistökatu 6A, 20520 Turku, Finland.
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42
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Cholesterol Organization in Phosphatidylcholine Liposomes: A Surface Plasmon Resonance Study. MATERIALS 2012. [PMCID: PMC5448994 DOI: 10.3390/ma5112306] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Models for the organization of sterols into regular arrays within phospholipid bilayers have been proposed previously. The existence of such arrays in real systems has been supported by the fact that concentration-dependent sterol properties show discontinuities at the cholesterol mole fractions corresponding to regular lattice arrangements. Experimental results presented here are based on a surface plasmon resonance assay that was used to analyze rates of cyclodextrin-mediated removal of cholesterol from adsorbed liposomes at cholesterol mole fractions up to χC = 0.55. Two kinetic pools of cholesterol were detected; there was a fast pool present at χC > 0.25, and a slow pool, with a removal rate that was dependent on the initial χC but that did not vary as χC decreased during the course of one experiment. The cholesterol activity therefore seems to be affected by sample history as well as local concentration, which could be explained in terms of the formation of superlattices that are stable for relatively long times. We also describe a variation on the traditional lattice models, with phosphatidylcholine (PC) being treated as an arrangement of hexagonal tiles; the cholesterol is then introduced at any vertex point, without increasing the total area occupied by all the lipid molecules. This model is consistent with Langmuir trough measurements of total lipid area and provides a simple explanation for the maximum solubility of cholesterol in the PC bilayer.
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43
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Prades J, Funari SS, Gomez-Florit M, Vögler O, Barceló F. Effect of a 2-hydroxylated fatty acid on Cholesterol-rich membrane domains. Mol Membr Biol 2012; 29:333-43. [DOI: 10.3109/09687688.2012.705023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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44
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Baykal-Caglar E, Hassan-Zadeh E, Saremi B, Huang J. Preparation of giant unilamellar vesicles from damp lipid film for better lipid compositional uniformity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2598-604. [PMID: 22652256 DOI: 10.1016/j.bbamem.2012.05.023] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 05/02/2012] [Accepted: 05/21/2012] [Indexed: 01/25/2023]
Abstract
Giant unilamellar vesicles (GUVs) containing cholesterol often have a wide distribution in lipid composition. In this study, GUVs of 1,2-dioleoyl-sn-glycero-3-phosphocholine(DOPC)/1,2-distearoyl-sn-glycero-3-phosphocholine(DSPC)/cholesterol and 1,2-diphytanoyl-sn-glycero-3-phosphocholine(diPhyPC)/1,2-dipalmitoyl-sn-glycero-3-phosphocholine(DPPC)/cholesterol were prepared from dry lipid films using the standard electroformation method as well as a modified method from damp lipid films, which are made from compositional uniform liposomes prepared using the Rapid Solvent Exchange (RSE) method. We quantified the lipid compositional distributions of GUV by measuring the miscibility transition temperature of GUVs using fluorescence microscopy, since a narrower distribution in the transition temperature should correspond to a more uniform distribution in GUV lipid composition. Cholesterol molecules can demix from other lipids in dry state and form cholesterol crystals. Using optical microscopy, micron-sized crystals were observed in some dry lipid films. Thus, a major cause of GUV lipid compositional heterogeneity is the demixing of lipids in the dry film state. By avoiding the dry film state, GUVs prepared from damp lipid films have a better uniformity in lipid composition, and the standard deviations of miscibility transition temperature are about 2.5 times smaller than that of GUVs prepared from dry lipid films. Comparing the two ternary systems, diPhyPC/DPPC/cholesterol GUVs has a larger cholesterol compositional heterogeneity, which directly correlates with the low maximum solubility of cholesterol in diPhyPC lipid bilayers (40.2±0.5mol%) measured by light scattering. Our data indicate that cholesterol interacts far less favorably with diPhyPC than it does with other PCs. The damp lipid film method also has a potential of preparing GUVs from cell membranes containing native proteins without going through a dry state.
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45
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Wennberg CL, van der Spoel D, Hub JS. Large influence of cholesterol on solute partitioning into lipid membranes. J Am Chem Soc 2012; 134:5351-61. [PMID: 22372465 DOI: 10.1021/ja211929h] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cholesterol plays an important role in maintaining the correct fluidity and rigidity of the plasma membrane of all animal cells, and hence, it is present in concentrations ranging from 20 to 50 mol %. Whereas the effect of cholesterol on such mechanical properties has been studied exhaustively over the last decades, the structural basis for cholesterol effects on membrane permeability is still unclear. Here we apply systematic molecular dynamics simulations to study the partitioning of solutes between water and membranes. We derive potentials of mean force for six different solutes permeating across 20 different lipid membranes containing one out of four types of phospholipids plus a cholesterol content varying from 0 to 50 mol %. Surprisingly, cholesterol decreases solute partitioning into the lipid tail region of the membranes much more strongly than expected from experiments on macroscopic membranes, suggesting that a laterally inhomogeneous cholesterol concentration and permeability may be required to explain experimental findings. The simulations indicate that the cost of breaking van der Waals interactions between the lipid tails of cholesterol-containing membranes account for the reduced partitioning rather than the surface area per phospholipid, which has been frequently suggested as a determinant for solute partitioning. The simulations further show that the partitioning is more sensitive to cholesterol (i) for larger solutes, (ii) in membranes with saturated as compared to membranes with unsaturated lipid tails, and (iii) in membranes with smaller lipid head groups.
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Affiliation(s)
- Christian L Wennberg
- Department of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box 596, SE-75124 Uppsala, Sweden
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46
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Alwarawrah M, Dai J, Huang J. Modification of Lipid Bilayer Structure by Diacylglycerol: A Comparative Study of Diacylglycerol and Cholesterol. J Chem Theory Comput 2012; 8:749-758. [PMID: 22389636 PMCID: PMC3289152 DOI: 10.1021/ct200790q] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Diacylglycerols (DAGs) are important second messengers in biomembranes, and they can activate protein kinase C and many other enzymes and receptors. However, their interactions with cholesterol and other lipids have not been previously studied using molecular dynamics (MD) simulation. In this study, nine independent atomistic MD simulations were performed to specifically investigate the interactions between di16:0DAG, 16:0,18:1-phosphatidylcholine (POPC), and cholesterol. Despite of their substantial differences in chemical structure, DAG and cholesterol produce some very similar effects in POPC bilayers: increasing acyl chain order and bilayer thickness, reducing volume-per-lipid, and decreasing lateral diffusion of molecules. More significantly, DAG also produces a strong "condensing effect" in PC bilayers. In comparison, cholesterol is more effective than DAG in producing the above effects. The driving force for the condensing effect is their molecular shape: DAG and cholesterol both have small polar headgroups and large hydrophobic bodies. In a lipid bilayer, in order to avoid the unfavorable exposure of their hydrophobic parts to water, neighboring phospholipid headgroups move toward cholesterol or DAG to provide cover. Thus, seemingly complex interactions between DAG, cholesterol and phospholipid can be clearly explained using the Umbrella Model. Our simulations confirmed the hypothesis that DAG increases the spacing between phospholipid headgroups, which is important for activating protein kinase C and other enzymes. Interestingly, our simulations also show that the conventional wisdom that the spacing created by a DAG is directly above the DAG molecule is incorrect; instead, the largest spacing usually occurs between the first and the second nearest-neighbor PC headgroups from a DAG, due to the umbrella effect.
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Affiliation(s)
| | - Jian Dai
- Department of Physics Texas Tech University Lubbock, Texas 79409
| | - Juyang Huang
- Department of Physics Texas Tech University Lubbock, Texas 79409
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47
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Sugár IP, Chong PLG. A statistical mechanical model of cholesterol/phospholipid mixtures: linking condensed complexes, superlattices, and the phase diagram. J Am Chem Soc 2011; 134:1164-71. [PMID: 22196210 DOI: 10.1021/ja2092322] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Despite extensive studies for nearly three decades, lateral distribution of molecules in cholesterol/phospholipid bilayers remains elusive. Here we present a statistical mechanical model of cholesterol/phospholipid mixtures that is able to rationalize almost every critical mole fraction (X(cr)) value previously reported for sterol superlattice formation as well as the observed biphasic changes in membrane properties at X(cr). This model is able to explain how cholesterol superlattices and cholesterol/phospholipid condensed complexes are interrelated. It gives a more detailed characterization of the LG(I)region (a broader region than the liquid disordered-liquid ordered mixed-phase region), which is considered to be a sludgelike mixture of fluid phase and aggregates of rigid clusters. A rigid cluster is formed by a cholesterol molecule and phospholipid molecules that are condensed to the cholesterol. Rigid clusters of similar size tend to form aggregates, in which cholesterol molecules are regularly distributed into superlattices. According to this model, the extent and type of sterol superlattices, thus the lateral distribution of the entire membrane, should vary with cholesterol mole fraction in a delicate, predictable, and nonmonotonic manner, which should have profound functional implications.
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Affiliation(s)
- István P Sugár
- Department of Neurology, Mount Sinai School of Medicine, New York, New York 10029, USA.
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Kerdous R, Heuvingh J, Bonneau S. Photo-dynamic induction of oxidative stress within cholesterol-containing membranes: Shape transitions and permeabilization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2965-72. [DOI: 10.1016/j.bbamem.2011.08.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2011] [Revised: 07/15/2011] [Accepted: 08/02/2011] [Indexed: 11/16/2022]
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Wydro P, Knapczyk S, Lapczyńska M. Variations in the condensing effect of cholesterol on saturated versus unsaturated phosphatidylcholines at low and high sterol concentration. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:5433-5444. [PMID: 21452813 DOI: 10.1021/la105142w] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this work, we have investigated the condensing and ordering effect induced by cholesterol on phosphatidylcholines (PCs). To perform the studies systematically, for the experiments we have selected phospholipids differing only in the number of cis monounsaturated chains (1,2-distearoyl-sn-glycero-3-phosphocholine--DSPC, 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine--SOPC, 1,2-dioleoyl-sn-glycero-3-phosphocholine--DOPC) or in the length (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine--POPC vs SOPC) of sn-1 acyl chain. Because the cholesterol concentration in mammalian membranes can be as high as 70 mol % of total lipids, the investigations were performed in a wide range of the sterol content. The results of the Langmuir monolayer experiments evidence that the relation between the structure of hydrophobic part of PC and the magnitude of the effects induced by cholesterol found at lower sterol content is different from that observed at higher sterol concentration. At a lower concentration of sterol (up to 30%), the condensing effect of cholesterol is stronger on saturated DSPC than on PCs containing monounsaturated chain(s), which is consistent with the conclusions drawn by other authors. However, at higher sterol content (≥50%), saturated DSPC is less susceptible to the influence of sterol than the investigated unsaturated PCs. To explain these irregularities, we have considered the strength of van der Waals interactions as well as the influence of sterol on the tilt of polar heads of PCs. It was also found that in the whole range of sterol concentration the ordering effect is stronger on saturated DSPC as compared to unsaturated phospholipids. However, at lower sterol content (up to 30%) the ordering effect induced on unsaturated PCs is rather weak, and the ordering does not change drastically in comparison with pure PCs film.
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Affiliation(s)
- Paweł Wydro
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland.
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Ko YT, Bickel U, Huang J. Polyethylenimine/oligonucleotide polyplexes investigated by fluorescence resonance energy transfer and fluorescence anisotropy. Oligonucleotides 2011; 21:109-14. [PMID: 21417932 DOI: 10.1089/oli.2010.0271] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
To advance knowledge on polyplex structure and composition, fluorescence resonance energy transfer (FRET) and anisotropy measurements were applied to polyplexes of rhodamine-labeled polyethylenimine (PEI) and fluorescein-labeled double-stranded oligodeoxynucleotide (ODN). About 25 kDa PEI was compared with low-molecular-weight PEI of 2.7 kDa. FRET reached maxima at amine to phosphate (N/P) ratios of 2 and 3 for 2.7 kDa and 25 kDa PEI, respectively, with similar average distances between donor and acceptor dye molecules in polyplexes. Anisotropy measurements allowed estimating the bound fractions of PEI and ODN. At N/P = 6, all ODN was bound, but only 58% of PEI 25 kDa and 45% of PEI 2.7 kDa. In conclusion, the higher molecular weight of PEI may conformationally restrict the availability of amino groups for charge interaction with phosphate groups in ODN. Moreover, significant fractions of both types of PEI remain free in solution at N/P ratios frequently used for transfection. FRET and anisotropy measurements provide effective tools for probing polyplex compositions and designing optimized delivery systems.
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Affiliation(s)
- Young Tag Ko
- Department of Pharmaceutical Engineering, Sangji University , Wonju, South Korea.
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