1
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Plasma membrane effects of sphingolipid-synthesis inhibition by myriocin in CHO cells: a biophysical and lipidomic study. Sci Rep 2022; 12:955. [PMID: 35046440 PMCID: PMC8770663 DOI: 10.1038/s41598-021-04648-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 11/08/2021] [Indexed: 11/08/2022] Open
Abstract
Suppression of a specific gene effect can be achieved by genetic as well as chemical methods. Each approach may hide unexpected drawbacks, usually in the form of side effects. In the present study, the specific inhibitor myriocin was used to block serine palmitoyltransferase (SPT), the first enzyme in the sphingolipid synthetic pathway, in CHO cells. The subsequent biophysical changes in plasma membranes were measured and compared with results obtained with a genetically modified CHO cell line containing a defective SPT (the LY-B cell line). Similar effects were observed with both approaches: sphingomyelin values were markedly decreased in myriocin-treated CHO cells and, in consequence, their membrane molecular order (measured as laurdan general polarization) and mechanical resistance (AFM-measured breakthrough force values) became lower than in the native, non-treated cells. Cells treated with myriocin reacted homeostatically to maintain membrane order, synthesizing more fully saturated and less polyunsaturated GPL than the non-treated ones, although they achieved it only partially, their plasma membranes remaining slightly more fluid and more penetrable than those from the control cells. The good agreement between results obtained with very different tools, such as genetically modified and chemically treated cells, reinforces the use of both methods and demonstrates that both are adequate for their intended use, i.e. the complete and specific inhibition of sphingolipid synthesis in CHO cells, without apparent unexpected effects.
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2
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Carravilla P, Dasgupta A, Zhurgenbayeva G, Danylchuk DI, Klymchenko AS, Sezgin E, Eggeling C. Long-term STED imaging of membrane packing and dynamics by exchangeable polarity-sensitive dyes. BIOPHYSICAL REPORTS 2021; 1:None. [PMID: 34939048 PMCID: PMC8651516 DOI: 10.1016/j.bpr.2021.100023] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 09/08/2021] [Indexed: 12/28/2022]
Abstract
Understanding the plasma membrane nanoscale organization and dynamics in living cells requires microscopy techniques with high spatial and temporal resolution that permit for long acquisition times and allow for the quantification of membrane biophysical properties, such as lipid ordering. Among the most popular super-resolution techniques, stimulated emission depletion (STED) microscopy offers one of the highest temporal resolutions, ultimately defined by the scanning speed. However, monitoring live processes using STED microscopy is significantly limited by photobleaching, which recently has been circumvented by exchangeable membrane dyes that only temporarily reside in the membrane. Here, we show that NR4A, a polarity-sensitive exchangeable plasma membrane probe based on Nile red, permits the super-resolved quantification of membrane biophysical parameters in real time with high temporal and spatial resolution as well as long acquisition times. The potential of this polarity-sensitive exchangeable dye is showcased by live-cell real-time three-dimensional STED recordings of bleb formation and lipid exchange during membrane fusion as well as by STED-fluorescence correlation spectroscopy experiments for the simultaneous quantification of membrane dynamics and lipid packing that correlate in model and live-cell membranes.
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Affiliation(s)
- Pablo Carravilla
- Leibniz Institute of Photonic Technology e.V., Jena, Germany
- Faculty of Physics and Astronomy, Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany
| | - Anindita Dasgupta
- Leibniz Institute of Photonic Technology e.V., Jena, Germany
- Faculty of Physics and Astronomy, Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany
| | - Gaukhar Zhurgenbayeva
- Faculty of Physics and Astronomy, Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany
- Jena School for Microbial Communication, Friedrich Schiller University Jena, Jena, Germany
| | - Dmytro I. Danylchuk
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Illkirch, France
| | - Andrey S. Klymchenko
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Illkirch, France
| | - Erdinc Sezgin
- Science for Life Laboratory, Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm, Sweden
| | - Christian Eggeling
- Leibniz Institute of Photonic Technology e.V., Jena, Germany
- Faculty of Physics and Astronomy, Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany
- Jena School for Microbial Communication, Friedrich Schiller University Jena, Jena, Germany
- Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
- Jena Center for Soft Matter, Jena, Germany
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3
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Huang C, Yang Y, Li Y, Lv G. A two-photon fluorescent lipid raft probe derived from dicyanostilbene and similar to cholesterol’s structure. MONATSHEFTE FUR CHEMIE 2021. [DOI: 10.1007/s00706-021-02826-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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4
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Monasterio BG, Jiménez-Rojo N, García-Arribas AB, Riezman H, Goñi FM, Alonso A. CHO/LY-B cell growth under limiting sphingolipid supply: Correlation between lipid composition and biophysical properties of sphingolipid-restricted cell membranes. FASEB J 2021; 35:e21657. [PMID: 34010474 DOI: 10.1096/fj.202001879rr] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 04/09/2021] [Accepted: 04/26/2021] [Indexed: 11/11/2022]
Abstract
Sphingolipids (SL) are ubiquitous in mammalian cell membranes, yet there is little data on the behavior of cells under SL-restriction conditions. LY-B cells derive from a CHO linein whichserine palmitoyl transferase (SPT), thus de novo SL synthesis, is suppressed, while maintaining the capacity of taking up and metabolizing exogenous sphingoid bases from the culture medium. In this study, LY-B cells were adapted to grow in a fetal bovine serum (FBS)-deficient medium to avoid external uptake of lipids. The lowest FBS concentration that allowed LY-B cell growth, though at a slow rate, under our conditions was 0.04%, that is, 250-fold less than the standard (10%) concentration. Cells grown under limiting SL concentrations remained viable for at least 72 hours. Enriching with sphingomyelin the SL-deficient medium allowed the recovery of growth rates analogous to those of control LY-B cells. Studies including whole cells, plasma membrane preparations, and derived lipid vesicles were carried out. Laurdan fluorescence was recorded to measure membrane molecular order, showing a significant decrease in the rigidity of LY-B cells, not only in plasma membrane but also in whole cell lipid extract, as a result of SL limitation in the growth medium. Plasma membrane preparations and whole cell lipid extracts were also studied using atomic force microscopy in the force spectroscopy mode. Force measurements demonstrated that lower breakthrough forces were required to penetrate samples obtained from SL-poor LY-B cells than those obtained from control cells. Mass-spectroscopic analysis was also a helpful tool to understand the rearrangement undergone by the LY-B cell lipid metabolism. The most abundant SL in LY-B cells, sphingomyelin, decreased by about 85% as a result of SL limitation in the medium, the bioactive lipid ceramide and the ganglioside precursor hexosylceramide decreased similarly, together with cholesterol. Quantitative SL analysis showed that a 250-fold reduction in sphingolipid supply to LY-B cells led only to a sixfold decrease in membrane sphingolipids, underlining the resistance to changes in composition of these cells. Plasma membrane compositions exhibited similar changes, at least qualitatively, as the whole cells with SL restriction. A linear correlation was observed between the sphingomyelin concentration in the membranes, the degree of lipid order as measured by laurdan fluorescence, and membrane breakthrough forces assessed by atomic force microscopy. Smaller, though significant, changes were also detected in glycerophospholipids under SL-restriction conditions.
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Affiliation(s)
- Bingen G Monasterio
- Instituto Biofisika (CSIC, UPV/EHU), Universidad del País Vasco, Leioa, Spain.,Departamento de Bioquímica, Universidad del País Vasco, Leioa, Spain
| | - Noemi Jiménez-Rojo
- NCCR Chemical Biology, Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Aritz B García-Arribas
- Instituto Biofisika (CSIC, UPV/EHU), Universidad del País Vasco, Leioa, Spain.,Departamento de Bioquímica, Universidad del País Vasco, Leioa, Spain
| | - Howard Riezman
- NCCR Chemical Biology, Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Félix M Goñi
- Instituto Biofisika (CSIC, UPV/EHU), Universidad del País Vasco, Leioa, Spain.,Departamento de Bioquímica, Universidad del País Vasco, Leioa, Spain
| | - Alicia Alonso
- Instituto Biofisika (CSIC, UPV/EHU), Universidad del País Vasco, Leioa, Spain.,Departamento de Bioquímica, Universidad del País Vasco, Leioa, Spain
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5
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Huang C, Kang S, Pan Q, Lv G. A Dicyanocarbazolylstilbene‐Derived Two‐Photon Fluorescence Probe for Lipid Raft with a Large Two‐Photon Action Cross Section. ChemistrySelect 2021. [DOI: 10.1002/slct.202100982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Chibao Huang
- School of Information Engineering Zunyi Normal University Zunyi 563002 China
- Henry Fok School of Biology and Agriculture Shaoguan University Shaoguan 512005 China
| | - Shuai Kang
- School of Information Engineering Zunyi Normal University Zunyi 563002 China
| | - Qi Pan
- School of Information Engineering Zunyi Normal University Zunyi 563002 China
| | - Guoling Lv
- School of Information Engineering Zunyi Normal University Zunyi 563002 China
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6
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Sych T, Gurdap CO, Wedemann L, Sezgin E. How Does Liquid-Liquid Phase Separation in Model Membranes Reflect Cell Membrane Heterogeneity? MEMBRANES 2021; 11:323. [PMID: 33925240 PMCID: PMC8146956 DOI: 10.3390/membranes11050323] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/22/2021] [Accepted: 04/26/2021] [Indexed: 11/22/2022]
Abstract
Although liquid-liquid phase separation of cytoplasmic or nuclear components in cells has been a major focus in cell biology, it is only recently that the principle of phase separation has been a long-standing concept and extensively studied in biomembranes. Membrane phase separation has been reconstituted in simplified model systems, and its detailed physicochemical principles, including essential phase diagrams, have been extensively explored. These model membrane systems have proven very useful to study the heterogeneity in cellular membranes, however, concerns have been raised about how reliably they can represent native membranes. In this review, we will discuss how phase-separated membrane systems can mimic cellular membranes and where they fail to reflect the native cell membrane heterogeneity. We also include a few humble suggestions on which phase-separated systems should be used for certain applications, and which interpretations should be avoided to prevent unreliable conclusions.
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Affiliation(s)
| | | | | | - Erdinc Sezgin
- Science for Life Laboratory, Department of Women’s and Children’s Health, Karolinska Institutet, 17165 Solna, Sweden; (T.S.); (C.O.G.); (L.W.)
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7
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Torralba J, de la Arada I, Carravilla P, Insausti S, Rujas E, Largo E, Eggeling C, Arrondo JLR, Apellániz B, Nieva JL. Cholesterol Constrains the Antigenic Configuration of the Membrane-Proximal Neutralizing HIV-1 Epitope. ACS Infect Dis 2020; 6:2155-2168. [PMID: 32584020 DOI: 10.1021/acsinfecdis.0c00243] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The envelope glycoprotein (Env) enables HIV-1 cell entry through fusion of host-cell and viral membranes induced by the transmembrane subunit gp41. Antibodies targeting the C-terminal sequence of the membrane-proximal external region (C-MPER) block the fusogenic activity of gp41 and achieve neutralization of divergent HIV-1 strains and isolates. Thus, recreating the structure that generates broadly neutralizing C-MPER antibodies during infection is a major goal in HIV vaccine development. Here, we have reconstituted a peptide termed CpreTM-TMD in a membrane environment. This peptide contains the C-MPER epitope and the minimum TMD residues required for the anchorage of the Env glycoprotein to the viral membrane. In addition, we have used antibody 10E8 variants to gauge the antigenic configuration attained by CpreTM-TMD as a function of the membrane cholesterol content, a functional determinant of the HIV envelope and liposome-based vaccines. Differential binding of the 10E8 variants and the trend of the IgG responses recovered from rabbits immunized with liposome-peptide formulations, suggested that cholesterol may restrict 10E8 accessibility to the C-MPER epitope. Our data ruled out the destabilization of the lipid bilayer architecture in CpreTM-TMD-containing membranes, and pointed to the perturbation of the helical conformation by lipid packing as the cause of the antigenic configuration loss induced by cholesterol. Overall, our results provide additional insights into the structural basis of the Env complex anchoring to membranes, and suggest new approaches to the design of effective immunogens directed against the near pan-neutralizing HIV-1 epitope C-MPER.
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Affiliation(s)
- Johana Torralba
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Igor de la Arada
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Pablo Carravilla
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Max-Wien Platz 1, 07743 Jena, Germany
- Leibniz Institute of Photonic Technology e.V., Albert-Einstein-Straße 9, 07745 Jena, Germany
| | - Sara Insausti
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Edurne Rujas
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Eneko Largo
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Immunology, Microbiology and Parasitology, Medicine and Odontology Faculty, University of Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Christian Eggeling
- Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Max-Wien Platz 1, 07743 Jena, Germany
- Leibniz Institute of Photonic Technology e.V., Albert-Einstein-Straße 9, 07745 Jena, Germany
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, OX3 9DS Oxford, U.K
| | - José L R Arrondo
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Beatriz Apellániz
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Physiology, Faculty of Pharmacy, University of the Basque Country (UPV/EHU), Paseo de la Universidad, 7, 01006 Vitoria-Gasteiz, Spain
| | - José L Nieva
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
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8
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Patches and Blebs: A Comparative Study of the Composition and Biophysical Properties of Two Plasma Membrane Preparations from CHO Cells. Int J Mol Sci 2020; 21:ijms21072643. [PMID: 32290157 PMCID: PMC7177368 DOI: 10.3390/ijms21072643] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 04/06/2020] [Accepted: 04/08/2020] [Indexed: 11/30/2022] Open
Abstract
This study was aimed at preparing and characterizing plasma membranes (PM) from Chinese Hamster Ovary (CHO) cells. Two methods of PM preparation were applied, one based on adhering cells to a poly-lysine-coated surface, followed by hypotonic lysis and removal of intracellular components, so that PM patches remain adhered to each other, and a second one consisting of bleb induction in cells, followed by separation of giant plasma membrane vesicles (GPMV). Both methods gave rise to PM in sufficient amounts to allow biophysical and biochemical characterization. Laurdan generalized polarization was used to measure molecular order in membranes, PM preparations were clearly more ordered than the average cell membranes (GP ≈0.450 vs. ≈0.20 respectively). Atomic force microscopy was used in the force spectroscopy mode to measure breakthrough forces of PM, both PM preparations provided values in the 4–6 nN range, while the corresponding value for whole cell lipid extracts was ≈2 nN. Lipidomic analysis of the PM preparations revealed that, as compared to the average cell membranes, PM were enriched in phospholipids containing 30–32 C atoms in their acyl chains but were relatively poor in those containing 34–40 C atoms. PM contained more saturated and less polyunsaturated fatty acids than the average cell membranes. Blebs (GPMV) and patches were very similar in their lipid composition, except that blebs contained four-fold the amount of cholesterol of patches (≈23 vs. ≈6 mol% total membrane lipids) while the average cell lipids contained 3 mol%. The differences in lipid composition are in agreement with the observed variations in physical properties between PM and whole cell membranes.
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9
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Photoacoustic effect applied on model membranes and living cells: direct observation with multiphoton excitation microscopy and long-term viability analysis. Sci Rep 2020; 10:299. [PMID: 31941922 PMCID: PMC6962462 DOI: 10.1038/s41598-019-56799-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 12/01/2019] [Indexed: 01/09/2023] Open
Abstract
The photoacoustic effect is generated when a variable light interacts with a strongly light-absorbing material. In water, it may produce hot bubbles and shock waves that could affect the integrity of nearby cellular membranes, opening transient pores (photoporation). In this study, we have evaluated the effect of pulsed laser-irradiated carbon nanoparticles (cNP) on model membranes and on Chinese hamster ovary (CHO) cells. Fluorescence lifetime measurements of calcein-loaded liposomes support the notion that the photoacoustic effect causes transient openings in membranes, allowing diffusion fluxes driven by gradient concentrations. With CHO cells, we have shown that this effect can induce either intracellular delivery of calcein, or release of cellular compounds. The latter process has been recorded live with multiphoton excitation microscopy during pulsed infrared laser irradiation. Calcein loading and cell viability were assayed by flow cytometry, measuring necrotic cells as well as those in early apoptosis. To further assess long-term cell recovery after the rather harsh treatment, cells were reseeded and their behaviour recorded for 48 h. These extended studies on cell viability show that pulsed laser cNP photoporation may be considered an adequate intracellular delivery technique only if employed with soft irradiation conditions (below 50 mJ/cm2).
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10
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Sibold J, Tewaag VE, Vagedes T, Mey I, Steinem C. Phase separation in pore-spanning membranes induced by differences in surface adhesion. Phys Chem Chem Phys 2020; 22:9308-9315. [DOI: 10.1039/d0cp00335b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A porous scaffold providing different adhesion energies alters the behaviour of coexisting phases in lipid membranes considerably.
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Affiliation(s)
- Jeremias Sibold
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Vera E. Tewaag
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Thomas Vagedes
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Ingo Mey
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Claudia Steinem
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
- Max Planck Institute for Dynamics and Self-Organization
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11
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Carravilla P, Darré L, Oar-Arteta IR, Vesga AG, Rujas E, de Las Heras-Martínez G, Domene C, Nieva JL, Requejo-Isidro J. The Bilayer Collective Properties Govern the Interaction of an HIV-1 Antibody with the Viral Membrane. Biophys J 2019; 118:44-56. [PMID: 31787208 DOI: 10.1016/j.bpj.2019.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 10/31/2019] [Accepted: 11/05/2019] [Indexed: 01/15/2023] Open
Abstract
Efficient engagement with the envelope glycoprotein membrane-proximal external region (MPER) results in robust blocking of viral infection by a class of broadly neutralizing antibodies (bnAbs) against human immunodeficiency virus (HIV). Developing an accommodation surface that engages with the viral lipid envelope appears to correlate with the neutralizing potency displayed by these bnAbs. The nature of the interactions established between the antibody and the lipid is nonetheless a matter of debate, with some authors arguing that anti-MPER specificity arises only under pathological conditions in autoantibodies endowed with stereospecific binding sites for phospholipids. However, bnAb-lipid interactions are often studied in systems that do not fully preserve the biophysical properties of lipid bilayers, and therefore, questions on binding specificity and the effect of collective membrane properties on the interaction are still open. Here, to evaluate the specificity of lipid interactions of an anti-MPER bnAb (4E10) in an intact membrane context, we determine quantitatively its association with lipid bilayers by means of scanning fluorescence correlation spectroscopy and all-atom molecular dynamic simulations. Our data support that 4E10 establishes electrostatic and hydrophobic interactions with the viral membrane surface and that the collective physical properties of the lipid bilayer influence 4E10 dynamics therein. We conclude that establishment of peripheral, nonspecific electrostatic interactions with the viral membrane through accommodation surfaces may assist high-affinity binding of HIV-1 MPER epitope at membrane interfaces. These findings highlight the importance of considering antibody-lipid interactions in the design of antibody-based anti-HIV strategies.
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Affiliation(s)
- Pablo Carravilla
- Instituto Biofisika (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Spain; Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain; Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Jena, Germany
| | - Leonardo Darré
- Functional Genomics Laboratory & Biomolecular Simulations Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Itziar R Oar-Arteta
- Instituto Biofisika (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Spain; Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Arturo G Vesga
- Instituto Biofisika (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Spain; Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Edurne Rujas
- Instituto Biofisika (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Spain; Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | | | - Carmen Domene
- Department of Chemistry, University of Bath, Claverton Down, Bath, United Kingdom; Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Jose L Nieva
- Instituto Biofisika (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Spain; Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain.
| | - Jose Requejo-Isidro
- Instituto Biofisika (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Spain; Centro Nacional de Biotecnología, CSIC, Madrid, Spain; Unidad de Nanobiotecnología, CNB-CSIC-IMDEA Nanociencia Associated Unit, Madrid, Spain.
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12
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Heras-Martínez GDL, Calleja V, Bailly R, Dessolin J, Larijani B, Requejo-Isidro J. A Complex Interplay of Anionic Phospholipid Binding Regulates 3'-Phosphoinositide-Dependent-Kinase-1 Homodimer Activation. Sci Rep 2019; 9:14527. [PMID: 31601855 PMCID: PMC6787260 DOI: 10.1038/s41598-019-50742-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 09/16/2019] [Indexed: 12/28/2022] Open
Abstract
3'-Phosphoinositide-dependent-Kinase-1 (PDK1) is a master regulator whereby its PI3-kinase-dependent dysregulation in human pathologies is well documented. Understanding the direct role for PtdIns(3,4,5)P3 and other anionic phospholipids in the regulation of PDK1 conformational dynamics and its downstream activation remains incomplete. Using advanced quantitative-time-resolved imaging (Fluorescence Lifetime Imaging and Fluorescence Correlation Spectroscopy) and molecular modelling, we show an interplay of antagonistic binding effects of PtdIns(3,4,5)P3 and other anionic phospholipids, regulating activated PDK1 homodimers. We demonstrate that phosphatidylserine maintains PDK1 in an inactive conformation. The dysregulation of the PI3K pathway affects the spatio-temporal and conformational dynamics of PDK1 and the activation of its downstream substrates. We have established a new anionic-phospholipid-dependent model for PDK1 regulation, depicting the conformational dynamics of multiple homodimer states. We show that the dysregulation of the PI3K pathway perturbs equilibrium between the PDK1 homodimer conformations. Our findings provide a role for the PtdSer binding site and its previously unrewarding role in PDK1 downregulation, suggesting a possible therapeutic strategy where the constitutively active dimer conformer of PDK1 may be rendered inactive by small molecules that drive it to its PtdSer-bound conformer.
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Affiliation(s)
- Gloria de Las Heras-Martínez
- Instituto Biofisika (CSIC, UPV/EHU), 48490, Leioa, Spain
- Cell Biophysics Laboratory, Ikerbasque Basque Foundation for Science, Instituto Biofisika (CSIC, UPV/EHU) & Research Centre for Experimental Marine Biology and Biotechnology (PiE), University of the Basque Country (UPV/EHU), Leioa, 48940, Spain
| | - Véronique Calleja
- Protein Phosphorylation Laboratory, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK
| | - Remy Bailly
- Institute of Chemistry & Biology of Membranes & Nanoobjects (UMR 5248 CBMN) CNRS - Université de Bordeaux - Bordeaux INP All. Geoffroy Saint-Hilaire, 33600, Pessac, France
| | - Jean Dessolin
- Institute of Chemistry & Biology of Membranes & Nanoobjects (UMR 5248 CBMN) CNRS - Université de Bordeaux - Bordeaux INP All. Geoffroy Saint-Hilaire, 33600, Pessac, France
| | - Banafshé Larijani
- Cell Biophysics Laboratory, Ikerbasque Basque Foundation for Science, Instituto Biofisika (CSIC, UPV/EHU) & Research Centre for Experimental Marine Biology and Biotechnology (PiE), University of the Basque Country (UPV/EHU), Leioa, 48940, Spain.
- Centre for Therapeutic Innovation (CTI-Bath); Cell Biophysics Laboratory Department of Pharmacy & Pharmacology University, Bath, Claverton Down, Bath, BA2 7AY, United Kingdom.
| | - Jose Requejo-Isidro
- Instituto Biofisika (CSIC, UPV/EHU), 48490, Leioa, Spain.
- Centro Nacional de Biotecnología (CSIC), Darwin, 3, E28049, Madrid, Spain.
- Unidad de Nanobiotecnología, CNB-CSIC-IMDEA Nanociencia Associated Unit, 28049, Madrid, Spain.
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13
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Steinkühler J, Sezgin E, Urbančič I, Eggeling C, Dimova R. Mechanical properties of plasma membrane vesicles correlate with lipid order, viscosity and cell density. Commun Biol 2019; 2:337. [PMID: 31531398 PMCID: PMC6744421 DOI: 10.1038/s42003-019-0583-3] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 08/15/2019] [Indexed: 11/08/2022] Open
Abstract
Regulation of plasma membrane curvature and composition governs essential cellular processes. The material property of bending rigidity describes the energetic cost of membrane deformations and depends on the plasma membrane molecular composition. Because of compositional fluctuations and active processes, it is challenging to measure it in intact cells. Here, we study the plasma membrane using giant plasma membrane vesicles (GPMVs), which largely preserve the plasma membrane lipidome and proteome. We show that the bending rigidity of plasma membranes under varied conditions is correlated to readout from environment-sensitive dyes, which are indicative of membrane order and microviscosity. This correlation holds across different cell lines, upon cholesterol depletion or enrichment of the plasma membrane, and variations in cell density. Thus, polarity- and viscosity-sensitive probes represent a promising indicator of membrane mechanical properties. Additionally, our results allow for identifying synthetic membranes with a few well defined lipids as optimal plasma membrane mimetics.
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Affiliation(s)
- Jan Steinkühler
- Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
| | - Erdinc Sezgin
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford, OX3 9DS UK
| | - Iztok Urbančič
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford, OX3 9DS UK
- Condensed Matter Physics Department, “Jožef Stefan” Institute, Ljubljana, Slovenia
| | - Christian Eggeling
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford, OX3 9DS UK
- Institute of Applied Optics Friedrich‐Schiller‐University Jena, Max-Wien Platz 4, 07743 Jena, Germany
- Leibniz Institute of Photonic Technology e.V., Albert-Einstein-Straße 9, 07745 Jena, Germany
| | - Rumiana Dimova
- Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
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14
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Velasco-Olmo A, Ormaetxea Gisasola J, Martinez Galvez JM, Vera Lillo J, Shnyrova AV. Combining patch-clamping and fluorescence microscopy for quantitative reconstitution of cellular membrane processes with Giant Suspended Bilayers. Sci Rep 2019; 9:7255. [PMID: 31076583 PMCID: PMC6510758 DOI: 10.1038/s41598-019-43561-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 04/26/2019] [Indexed: 01/24/2023] Open
Abstract
In vitro reconstitution and microscopic visualization of membrane processes is an indispensable source of information about a cellular function. Here we describe a conceptionally novel free-standing membrane template that facilitates such quantitative reconstitution of membrane remodelling at different scales. The Giant Suspended Bilayers (GSBs) spontaneously swell from lipid lamella reservoir deposited on microspheres. GSBs attached to the reservoir can be prepared from virtually any lipid composition following a fast procedure. Giant unilamellar vesicles can be further obtained by GSB detachment from the microspheres. The reservoir stabilizes GSB during deformations, mechanical micromanipulations, and fluorescence microscopy observations, while GSB-reservoir boundary enables the exchange of small solutes with GSB interior. These unique properties allow studying macro- and nano-scale membrane deformations, adding membrane-active compounds to both sides of GSB membrane and applying patch-clamp based approaches, thus making GSB a versatile tool for reconstitution and quantification of cellular membrane trafficking events.
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Affiliation(s)
- Ariana Velasco-Olmo
- Biofisika Institute (UPV/EHU, CSIC) and Department of Biochemistry and Molecular Biology, University of the Basque Country, Bilbao, Spain
| | - Julene Ormaetxea Gisasola
- Biofisika Institute (UPV/EHU, CSIC) and Department of Biochemistry and Molecular Biology, University of the Basque Country, Bilbao, Spain
| | - Juan Manuel Martinez Galvez
- Biofisika Institute (UPV/EHU, CSIC) and Department of Biochemistry and Molecular Biology, University of the Basque Country, Bilbao, Spain
| | - Javier Vera Lillo
- Biofisika Institute (UPV/EHU, CSIC) and Department of Biochemistry and Molecular Biology, University of the Basque Country, Bilbao, Spain
| | - Anna V Shnyrova
- Biofisika Institute (UPV/EHU, CSIC) and Department of Biochemistry and Molecular Biology, University of the Basque Country, Bilbao, Spain.
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15
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Dimova R. Giant Vesicles and Their Use in Assays for Assessing Membrane Phase State, Curvature, Mechanics, and Electrical Properties. Annu Rev Biophys 2019; 48:93-119. [DOI: 10.1146/annurev-biophys-052118-115342] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Giant unilamellar vesicles represent a promising and extremely useful model biomembrane system for systematic measurements of mechanical, thermodynamic, electrical, and rheological properties of lipid bilayers as a function of membrane composition, surrounding media, and temperature. The most important advantage of giant vesicles over other model membrane systems is that the membrane responses to external factors such as ions, (macro)molecules, hydrodynamic flows, or electromagnetic fields can be directly observed under the microscope. Here, we briefly review approaches for giant vesicle preparation and describe several assays used for deducing the membrane phase state and measuring a number of material properties, with further emphasis on membrane reshaping and curvature.
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Affiliation(s)
- Rumiana Dimova
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
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16
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Masukawa MK, Vequi-Suplicy CC, Duarte EL, Lamy MT. A closer look into laurdan as a probe to monitor cationic DODAB bilayers. J Photochem Photobiol A Chem 2019. [DOI: 10.1016/j.jphotochem.2019.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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17
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Knorr RL, Steinkühler J, Dimova R. Micron-sized domains in quasi single-component giant vesicles. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1957-1964. [DOI: 10.1016/j.bbamem.2018.06.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 06/25/2018] [Accepted: 06/26/2018] [Indexed: 12/29/2022]
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18
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Sych T, Mély Y, Römer W. Lipid self-assembly and lectin-induced reorganization of the plasma membrane. Philos Trans R Soc Lond B Biol Sci 2018; 373:20170117. [PMID: 29632269 PMCID: PMC5904303 DOI: 10.1098/rstb.2017.0117] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2018] [Indexed: 01/10/2023] Open
Abstract
The plasma membrane represents an outstanding example of self-organization in biology. It plays a vital role in protecting the integrity of the cell interior and regulates meticulously the import and export of diverse substances. Its major building blocks are proteins and lipids, which self-assemble to a fluid lipid bilayer driven mainly by hydrophobic forces. Even if the plasma membrane appears-globally speaking-homogeneous at physiological temperatures, the existence of specialized nano- to micrometre-sized domains of raft-type character within cellular and synthetic membrane systems has been reported. It is hypothesized that these domains are the origin of a plethora of cellular processes, such as signalling or vesicular trafficking. This review intends to highlight the driving forces of lipid self-assembly into a bilayer membrane and the formation of small, transient domains within the plasma membrane. The mechanisms of self-assembly depend on several factors, such as the lipid composition of the membrane and the geometry of lipids. Moreover, the dynamics and organization of glycosphingolipids into nanometre-sized clusters will be discussed, also in the context of multivalent lectins, which cluster several glycosphingolipid receptor molecules and thus create an asymmetric stress between the two membrane leaflets, leading to tubular plasma membrane invaginations.This article is part of the theme issue 'Self-organization in cell biology'.
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Affiliation(s)
- Taras Sych
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany
- Centre for Biological Signalling Studies (BIOSS), Albert-Ludwigs-University Freiburg, Schänzlestraße 18, 79104 Freiburg, Germany
- Freiburg Center for Interactive Materials and Bioinspired Technology (FIT), Albert-Ludwigs-University Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, 67401 Illkirch Cedex, France
| | - Yves Mély
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, 67401 Illkirch Cedex, France
| | - Winfried Römer
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany
- Centre for Biological Signalling Studies (BIOSS), Albert-Ludwigs-University Freiburg, Schänzlestraße 18, 79104 Freiburg, Germany
- Freiburg Center for Interactive Materials and Bioinspired Technology (FIT), Albert-Ludwigs-University Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
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19
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Functional Optimization of Broadly Neutralizing HIV-1 Antibody 10E8 by Promotion of Membrane Interactions. J Virol 2018; 92:JVI.02249-17. [PMID: 29386285 DOI: 10.1128/jvi.02249-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 01/26/2018] [Indexed: 11/20/2022] Open
Abstract
The 10E8 antibody targets a helical epitope in the membrane-proximal external region (MPER) and transmembrane domain (TMD) of the envelope glycoprotein (Env) subunit gp41 and is among the broadest known neutralizing antibodies against HIV-1. Accordingly, this antibody and its mechanism of action valuably inform the design of effective vaccines and immunotherapies. 10E8 exhibits unusual adaptations to attain specific, high-affinity binding to the MPER at the viral membrane interface. Reversing the charge of the basic paratope surface (from net positive to net negative) reportedly lowered its neutralization potency. Here, we hypothesized that by increasing the net positive charge in similar polar surface patches, the neutralization potency of the antibody may be enhanced. We found that an increased positive charge at this paratope surface strengthened an electrostatic interaction between the antibody and lipid bilayers, enabling 10E8 to interact spontaneously with membranes. Notably, the modified 10E8 antibody did not gain any apparent polyreactivity and neutralized virus with a significantly greater potency. Binding analyses indicated that the optimized 10E8 antibody bound with a higher affinity to the epitope peptide anchored in lipid bilayers and to Env spikes on virions. Overall, our data provide a proof of principle for the rational optimization of 10E8 via manipulation of its interaction with the membrane element of its epitope. However, the observation that a similar mutation strategy did not affect the potency of the first-generation anti-MPER antibody 4E10 shows possible limitations of this principle. Altogether, our results emphasize the crucial role played by the viral membrane in the antigenicity of the MPER-TMD of HIV-1.IMPORTANCE The broadly neutralizing antibody 10E8 blocks infection by nearly all HIV-1 isolates, a capacity which vaccine design seeks to reproduce. Engineered versions of this antibody also represent a promising treatment for HIV infection by passive immunization. Understanding its mechanism of action is therefore important to help in developing effective vaccines and biologics to combat HIV/AIDS. 10E8 engages its helical MPER epitope where the base of the envelope spike submerges into the viral membrane. To enable this interaction, this antibody evolved an unusual property: the ability to interact with the membrane surface. Here, we provide evidence that 10E8 can be made more effective by enhancing its interactions with membranes. Our findings strengthen the idea that to elicit antibodies similar to 10E8, vaccines must reproduce the membrane environment where these antibodies perform their function.
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20
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Gambade A, Zreika S, Guéguinou M, Chourpa I, Fromont G, Bouchet AM, Burlaud-Gaillard J, Potier-Cartereau M, Roger S, Aucagne V, Chevalier S, Vandier C, Goupille C, Weber G. Activation of TRPV2 and BKCa channels by the LL-37 enantiomers stimulates calcium entry and migration of cancer cells. Oncotarget 2018; 7:23785-800. [PMID: 26993604 PMCID: PMC5029663 DOI: 10.18632/oncotarget.8122] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 02/28/2016] [Indexed: 12/20/2022] Open
Abstract
Expression of the antimicrobial peptide hCAP18/LL-37 is associated to malignancy in various cancer forms, stimulating cell migration and metastasis. We report that LL-37 induces migration of three cancer cell lines by activating the TRPV2 calcium-permeable channel and recruiting it to pseudopodia through activation of the PI3K/AKT pathway. Ca2+ entry through TRPV2 cooperated with a K+ efflux through the BKCa channel. In a panel of human breast tumors, the expression of TRPV2 and LL-37 was found to be positively correlated. The D-enantiomer of LL-37 showed identical effects as the L-peptide, suggesting that no binding to a specific receptor was involved. LL-37 attached to caveolae and pseudopodia membranes and decreased membrane fluidity, suggesting that a modification of the physical properties of the lipid membrane bilayer was the underlying mechanism of its effects.
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Affiliation(s)
- Audrey Gambade
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours, France
| | - Sami Zreika
- Department of Medical Lab Technology, Jinan University, Tripoli, Lebanon
| | - Maxime Guéguinou
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours, France.,Ion Channel Network Canceropole Grand Ouest, Nantes, France
| | | | - Gaëlle Fromont
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours, France.,Ion Channel Network Canceropole Grand Ouest, Nantes, France.,CHRU Hôpital Bretonneau, Tours, France
| | - Ana Maria Bouchet
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours, France.,Ion Channel Network Canceropole Grand Ouest, Nantes, France
| | | | - Marie Potier-Cartereau
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours, France.,Ion Channel Network Canceropole Grand Ouest, Nantes, France
| | - Sébastien Roger
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours, France
| | - Vincent Aucagne
- Centre de Biophysique Moléculaire, CNRS UPR 4301, Orléans, France
| | | | - Christophe Vandier
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours, France.,Ion Channel Network Canceropole Grand Ouest, Nantes, France
| | - Caroline Goupille
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours, France.,CHRU Hôpital Bretonneau, Tours, France
| | - Günther Weber
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours, France.,Université François Rabelais, Tours, France
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21
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Carravilla P, Cruz A, Martin-Ugarte I, Oar-Arteta IR, Torralba J, Apellaniz B, Pérez-Gil J, Requejo-Isidro J, Huarte N, Nieva JL. Effects of HIV-1 gp41-Derived Virucidal Peptides on Virus-like Lipid Membranes. Biophys J 2017; 113:1301-1310. [PMID: 28797705 DOI: 10.1016/j.bpj.2017.06.061] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 06/22/2017] [Accepted: 06/29/2017] [Indexed: 12/11/2022] Open
Abstract
Membrane fusion induced by the envelope glycoprotein enables the intracellular replication of HIV-1; hence, this process constitutes a major target for antiretroviral compounds. It has been proposed that peptides having propensity to interact with membrane interfaces might exert broad antiviral activity against enveloped viruses. To test this hypothesis, in this contribution we have analyzed the antiviral effects of peptides derived from the membrane-proximal external region and the transmembrane domain of the envelope glycoprotein subunit gp41, which display different degrees of interfacial hydrophobicity. Our data support the virucidal activity of a region that combines hydrophobic-at-interface membrane-proximal external region aromatics with hydrophobic residues of the transmembrane domain, and contains the absolutely conserved 679LWYIK/R683 sequence, proposed to embody a "cholesterol recognition/interaction amino acid consensus" motif. We further sought to correlate the antiviral activity of these peptides and their effects on membranes that mimic lipid composition and biophysical properties of the viral envelope. The data revealed that peptides endowed with virucidal activity were membrane active and induced permeabilization and fusion of virus-like lipid vesicles. In addition, they modulated lipid packing and miscibility of laterally segregated liquid domains, two properties that depend on the high cholesterol content of the viral membrane. Thus, the overall experimental evidence is consistent with a pattern of HIV inhibition that involves direct alteration of the physical chemistry of the virus membrane. Furthermore, the sequence-dependent effects observed might guide the development of new virucidal peptides.
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Affiliation(s)
- Pablo Carravilla
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Antonio Cruz
- Department of Biochemistry and Molecular Biology, Faculty of Biology, Complutense University, Madrid, Spain; Healthcare Research Institute of Hospital 12 de Octubre, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Itziar Martin-Ugarte
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Itziar R Oar-Arteta
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Johanna Torralba
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Beatriz Apellaniz
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Jesús Pérez-Gil
- Department of Biochemistry and Molecular Biology, Faculty of Biology, Complutense University, Madrid, Spain; Healthcare Research Institute of Hospital 12 de Octubre, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - José Requejo-Isidro
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Nerea Huarte
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain.
| | - José L Nieva
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain.
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22
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Huarte N, Carravilla P, Cruz A, Lorizate M, Nieto-Garai JA, Kräusslich HG, Pérez-Gil J, Requejo-Isidro J, Nieva JL. Functional organization of the HIV lipid envelope. Sci Rep 2016; 6:34190. [PMID: 27678107 PMCID: PMC5039752 DOI: 10.1038/srep34190] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 09/08/2016] [Indexed: 12/17/2022] Open
Abstract
The chemical composition of the human immunodeficiency virus type 1 (HIV-1) membrane is critical for fusion and entry into target cells, suggesting that preservation of a functional lipid bilayer organization may be required for efficient infection. HIV-1 acquires its envelope from the host cell plasma membrane at sites enriched in raft-type lipids. Furthermore, infectious particles display aminophospholipids on their surface, indicative of dissipation of the inter-leaflet lipid asymmetry metabolically generated at cellular membranes. By combining two-photon excited Laurdan fluorescence imaging and atomic force microscopy, we have obtained unprecedented insights into the phase state of membranes reconstituted from viral lipids (i.e., extracted from infectious HIV-1 particles), established the role played by the different specimens in the mixtures, and characterized the effects of membrane-active virucidal agents on membrane organization. In determining the molecular basis underlying lipid packing and lateral heterogeneity of the HIV-1 membrane, our results may help develop compounds with antiviral activity acting by perturbing the functional organization of the lipid envelope.
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Affiliation(s)
- Nerea Huarte
- Biophysics Unit (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - Pablo Carravilla
- Biophysics Unit (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - Antonio Cruz
- Department of Biochemistry, Faculty of Biology, and Research Institute Hospital 12 de Octubre, Universidad Complutense, Madrid, Spain
| | - Maier Lorizate
- Biophysics Unit (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain.,Department of Infectious Diseases, Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Jon A Nieto-Garai
- Biophysics Unit (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - Hans-Georg Kräusslich
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Jesús Pérez-Gil
- Department of Biochemistry, Faculty of Biology, and Research Institute Hospital 12 de Octubre, Universidad Complutense, Madrid, Spain
| | - Jose Requejo-Isidro
- Biophysics Unit (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - José L Nieva
- Biophysics Unit (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
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23
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Solution Asymmetry and Salt Expand Fluid-Fluid Coexistence Regions of Charged Membranes. Biophys J 2016; 110:2581-2584. [PMID: 27288275 PMCID: PMC4919722 DOI: 10.1016/j.bpj.2016.05.028] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 04/26/2016] [Accepted: 05/16/2016] [Indexed: 01/08/2023] Open
Abstract
Liquid-liquid phase separation in giant unilamellar vesicles (GUVs) leads to the formation of intramembrane domains. To mimic charged biological membranes, we studied phase separation and domain formation in GUVs of ternary lipid mixtures composed of egg sphingomyelin, cholesterol, and the negatively charged lipid dioleoylphosphatidylglycerol. The GUVs were exposed to solutions of sucrose and high-saline buffer. The phase diagram was determined using epifluorescence microscopy for vesicle populations with symmetric and asymmetric solution compositions across the membranes. Trans-membrane solution asymmetry was found to affect the membrane phase state. Furthermore, compared to the case of salt-free conditions, the phase diagram in the presence of high-saline buffer (both symmetrically or asymmetrically present across the membrane) was found to exhibit a significantly extended region of liquid-ordered and liquid-disordered coexistence. These observations were confirmed on single GUVs using microfluidics and confocal microscopy. Moreover, we found that the miscibility temperatures markedly increased for vesicles in the presence of symmetric and asymmetric salt solutions. Our results demonstrate a substantial effect of salt and solution asymmetry on the phase behavior of charged membranes, which has direct implications for protein adsorption onto these membranes and for the repartitioning of proteins within the membrane domains.
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24
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Okamoto Y, Kishi Y, Ishigami T, Suga K, Umakoshi H. Chiral Selective Adsorption of Ibuprofen on a Liposome Membrane. J Phys Chem B 2016; 120:2790-5. [DOI: 10.1021/acs.jpcb.6b00840] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yukihiro Okamoto
- Division
of Chemical Engineering,
Graduate School of Engineering Science, Osaka University, 1-3
Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
| | - Yusuke Kishi
- Division
of Chemical Engineering,
Graduate School of Engineering Science, Osaka University, 1-3
Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
| | - Takaaki Ishigami
- Division
of Chemical Engineering,
Graduate School of Engineering Science, Osaka University, 1-3
Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
| | - Keishi Suga
- Division
of Chemical Engineering,
Graduate School of Engineering Science, Osaka University, 1-3
Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
| | - Hiroshi Umakoshi
- Division
of Chemical Engineering,
Graduate School of Engineering Science, Osaka University, 1-3
Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
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25
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The importance of hydrogen bonding in sphingomyelin's membrane interactions with co-lipids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:304-10. [DOI: 10.1016/j.bbamem.2015.12.008] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 11/16/2015] [Accepted: 12/03/2015] [Indexed: 01/10/2023]
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26
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Onuki Y, Obata Y, Kawano K, Sano H, Matsumoto R, Hayashi Y, Takayama K. Membrane Microdomain Structures of Liposomes and Their Contribution to the Cellular Uptake Efficiency into HeLa Cells. Mol Pharm 2016; 13:369-78. [PMID: 26709741 DOI: 10.1021/acs.molpharmaceut.5b00601] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The purpose of this study is to obtain a comprehensive relationship between membrane microdomain structures of liposomes and their cellular uptake efficiency. Model liposomes consisting of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)/1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/cholesterol (Ch) were prepared with various lipid compositions. To detect distinct membrane microdomains in the liposomes, fluorescence-quenching assays were performed at temperatures ranging from 25 to 60 °C using 1,6-diphenyl-1,3,5-hexatriene-labeled liposomes and (2,2,6,6-tetramethylpiperidin-1-yl)oxyl. From the data analysis using the response surface method, we gained a better understanding of the conditions for forming distinct domains (Lo, Ld, and gel phase membranes) as a function of lipid composition. We further performed self-organizing maps (SOM) clustering to simplify the complicated behavior of the domain formation to obtain its essence. As a result, DPPC/DOPC/Ch liposomes in any lipid composition were integrated into five distinct clusters in terms of similarity of the domain structure. In addition, the findings from synchrotron small-angle X-ray scattering analysis offered further insight into the domain structures. As a last phase of this study, an in vitro cellular uptake study using HeLa cells was conducted using SOM clusters' liposomes with/without PEGylation. As a consequence of this study, higher cellular uptake was observed from liposomes having Ch-rich ordered domains.
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Affiliation(s)
- Yoshinori Onuki
- Department of Pharmaceutical Technology, Graduate School of Medical and Pharmaceutical Science, Unversity of Toyama , Sugitani 2630, Toyama-shi, Toyama 930-0194, Japan
| | - Yasuko Obata
- Department of Pharmaceutics and §Department of Drug Delivery Research, Hoshi University , Ebara 2-4-41, Shinagawa, Tokyo 142-8501, Japan
| | | | - Hiromu Sano
- Department of Pharmaceutics and §Department of Drug Delivery Research, Hoshi University , Ebara 2-4-41, Shinagawa, Tokyo 142-8501, Japan
| | - Reina Matsumoto
- Department of Pharmaceutics and §Department of Drug Delivery Research, Hoshi University , Ebara 2-4-41, Shinagawa, Tokyo 142-8501, Japan
| | - Yoshihiro Hayashi
- Department of Pharmaceutical Technology, Graduate School of Medical and Pharmaceutical Science, Unversity of Toyama , Sugitani 2630, Toyama-shi, Toyama 930-0194, Japan
| | - Kozo Takayama
- Department of Pharmaceutics and §Department of Drug Delivery Research, Hoshi University , Ebara 2-4-41, Shinagawa, Tokyo 142-8501, Japan
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