1
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Münch NS, Das S, Seeger S. Unveiling the effect of CaCl 2 on amyloid β aggregation via supercritical angle Raman and fluorescence spectroscopy and microscopy. Phys Chem Chem Phys 2024. [PMID: 39371012 PMCID: PMC11456997 DOI: 10.1039/d4cp00996g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 10/01/2024] [Indexed: 10/08/2024]
Abstract
Amyloid β aggregation is an important factor in Alzheimer's disease. Since calcium homeostasis plays an important role in amyloid β aggregation, it is crucial to study the interaction between calcium ions and amyloid β directly at the surface of the lipid membrane. With supercritical angle techniques, the signal of interest at the surface is easily separated from the bulk solution, making them a powerful tool for aggregation study. In this work, the influence of calcium ions on amyloid β aggregation over different aggregation time periods is investigated with supercritical angle Raman and fluorescence spectroscopy and microscopy. Note that calcium ions have a larger influence on amyloid β1-42 than on the 40 amino acid variant. We found that a small layer of calcium ions significantly protects the lipid membrane against the protein insertion process.
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Affiliation(s)
- Nathalia Simea Münch
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
| | - Subir Das
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
| | - Stefan Seeger
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
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2
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Veretenenko II, Trofimov YA, Krylov NA, Efremov RG. Nanoscale lipid domains determine the dynamic molecular portraits of mixed DOPC/DOPS bilayers in a fluid phase: A computational insight. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184376. [PMID: 39111381 DOI: 10.1016/j.bbamem.2024.184376] [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: 03/28/2024] [Revised: 08/01/2024] [Accepted: 08/01/2024] [Indexed: 08/12/2024]
Abstract
Lateral heterogeneity, or mosaicity, is a fundamental property inherent to cell membranes that is crucial for their functioning. While microscopic inhomogeneities (e.g. rafts) are easily detected experimentally, lipid domains with nanoscale dimensions (nanoclusters of nanodomains, NDs) resist reliable characterization by instrumental methods. In such a case, important insight can be gained via computer modeling. Here, NDs composed of lipid's head groups in the mixed zwitterionic dioleoylphosphatidylcholine (DOPC) and negatively charged dioleoylphosphatidylserine (DOPS) bilayers were studied by molecular dynamics. A new algorithm has been developed to identify NDs. Unlike most similar methods, it implicitly considers the heterogeneous distribution of lipid head atomic density and does not require subjectively chosen parameters. In DOPS-rich membranes, lipids form more compact and stable NDs due to strong interlipid interactions. In DOPC-rich systems, NDs arise due to the "packing" effect of weakly bound lipid heads. The clustering picture is related to the physical properties of the bilayer surface: DOPS-rich systems show more pronounced surface heterogeneity of hydrophilic/hydrophobic regions compared to DOPC-rich ones. The results obtained are important for the effective quantitative characterization of the "dynamic molecular portrait" of a membrane surface - its "fingerprint" characterizing dynamical distribution of its physicochemical properties.
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Affiliation(s)
- Irina I Veretenenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia; Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Moscow region 141701, Russia.
| | - Yury A Trofimov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - Nikolay A Krylov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - Roman G Efremov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia; Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Moscow region 141701, Russia; National Research University Higher School of Economics, Moscow 101000, Russia.
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3
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Mohanta S, Das NK, Saha S, Goswami C. Capsaicin-insensitivity of TRPV1-R575D mutant located at the lipid-water-interface region can be rescued by either extracellular Ca 2+-chelation or cholesterol reduction. Neurochem Int 2024; 179:105826. [PMID: 39117000 DOI: 10.1016/j.neuint.2024.105826] [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: 06/16/2024] [Revised: 07/20/2024] [Accepted: 08/04/2024] [Indexed: 08/10/2024]
Abstract
TRPV1 acts as a unique polymodal ion channel having distinct structure and gating properties. In this context, TRPV1-R575D represents a special mutant located at the inner lipid-water-interface (LWI) region that has less possibility of interaction with membrane cholesterol. In control conditions, this lab-generated mutant of TRPV1 shows no "ligand-sensitivity", reduced surface expression, reduced localization in the lipid rafts, yet induces high cellular lethality. Notably, the cellular lethality induced by TRPV1-R575D expression can be rescued by adding 5'I-RTX (a specific inhibitor of TRPV1) or by introducing another mutation in the next position, i.e. in TRPV1-R575D/D576R. In this work we characterized TRPV1-R575D and TRPV1-R575D/D576R mutants in different cellular conditions and compared with the TRPV1-WT. We report that the "ligand-insensitivity" of TRPV1-R575D can be rescued in certain conditions, such as by chelation of extracellular Ca2+, or by reduction of the membrane cholesterol. Here we show that Ca2+ plays an important role in the channel gating of TRPV1-WT as well as LWI mutants (TRPV1-R575D, TRPV1-R575D/D576R). However, chelation of intracellular Ca2+ or depletion of ER Ca2+ did not have a significant effect on the TRPV1-R575D. Certain properties related to channel gating of mutant TRPV1-R575D/D576R can be rescued partially or fully in a context -dependent manner. Cholesterol depletion also alters these properties. Our data suggests that lower intracellular basal Ca2+ acts as a pre-requisite for further opening of TRPV1-R575D. These findings enable better understanding of the structure-function relationship of TRPV1 and may be critical in comprehending the channelopathies induced by other homologous thermosensitive TRPVs.
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Affiliation(s)
- Sushama Mohanta
- School of Biological Sciences, National Institute of Science Education and Research, HBNI, Khordha, Jatni, Odisha, 752050, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, 400094, India
| | - Nilesh Kumar Das
- School of Biological Sciences, National Institute of Science Education and Research, HBNI, Khordha, Jatni, Odisha, 752050, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, 400094, India
| | - Somdatta Saha
- School of Biological Sciences, National Institute of Science Education and Research, HBNI, Khordha, Jatni, Odisha, 752050, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, 400094, India
| | - Chandan Goswami
- School of Biological Sciences, National Institute of Science Education and Research, HBNI, Khordha, Jatni, Odisha, 752050, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, 400094, India.
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4
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Wang B, Tieleman DP. The structure, self-assembly and dynamics of lipid nanodiscs revealed by computational approaches. Biophys Chem 2024; 309:107231. [PMID: 38569455 DOI: 10.1016/j.bpc.2024.107231] [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: 01/24/2024] [Revised: 03/27/2024] [Accepted: 03/28/2024] [Indexed: 04/05/2024]
Abstract
Nanodisc technology is increasingly being used in structural, biochemical and biophysical studies of membrane proteins. The computational approaches have revealed many important features of nanodisc assembly, structures and dynamics. Therefore, we reviewed the application of computational approaches, especially molecular modeling and molecular dyncamics (MD) simulations, to characterize nanodiscs, including the structural models, assembly and disassembly, protocols for modeling, structural properties and dynamics, and protein-lipid interactions in nanodiscs. More amazing computational studies about nanodiscs are looked forward to in the future.
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Affiliation(s)
- Beibei Wang
- Centre for Advanced Materials Research, Beijing Normal University, Zhuhai 519087, China.
| | - D Peter Tieleman
- Department of Biological Sciences and Centre for Molecular Simulation, University of Calgary, Calgary T2N 1N4, Canada.
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5
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Bernstein AD, Yang Y, Osborn Popp TM, Ampadu GA, Acharya GR, Nieuwkoop AJ. Effects of Ca 2+ on the Structure and Dynamics of PIP3 in Model Membranes Containing PC and PS. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.28.596302. [PMID: 38854128 PMCID: PMC11160587 DOI: 10.1101/2024.05.28.596302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Phosphatidylinositol phosphates (PIPs) are a family of seven different eukaryotic membrane lipids that have a large role in cell viability, despite their minor concentration in eukaryotic cellular membranes. PIPs tightly regulate cellular processes such as cellular growth, metabolism, immunity, and development through direct interactions with partner proteins. Understanding the biophysical properties of PIPs in the complex membrane environment is important to understand how PIPs selectively regulate a partner protein. Here we investigate the structure and dynamics of PIP3 in lipid bilayers that are simplified models of the natural membrane environment. We probe the effects of the anionic lipid phosphatidylserine (PS) and the divalent cation Ca 2+ . We use solution and solid-state 1 H, 31 P, and 13 C NMR all at natural abundance combined with MD simulations to characterize the structure and dynamics of PIPs. 1 H and 31 P 1D spectra show good resolution at high temperatures with isolated peaks in the headgroup, interfacial, and bilayer regions. Site specific assignment of these 1D reporters were made and used to measure the effects of Ca 2+ and PS. In particular, the resolved 31 P signals of the PIP3 headgroup allowed for extremely well localized information about PIP3 phosphate dynamics, which the MD simulations were able to help explain. Cross polarization kinetics provided additional site-specific dynamics measurements for the PIP3 headgroups.
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6
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Ohkubo YZ, Radulovic PW, Kahira AN, Madsen JJ. Membrane binding and lipid-protein interaction of the C2 domain from coagulation factor V. Curr Res Struct Biol 2024; 7:100149. [PMID: 38766652 PMCID: PMC11098723 DOI: 10.1016/j.crstbi.2024.100149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 03/28/2024] [Accepted: 04/29/2024] [Indexed: 05/22/2024] Open
Abstract
Anchoring of coagulation factors to anionic regions of the membrane involves the C2 domain as a key player. The rate of enzymatic reactions of the coagulation factors is increased by several orders of magnitude upon membrane binding. However, the precise mechanisms behind the rate acceleration remain unclear, primarily because of a lack of understanding of the conformational dynamics of the C2-containing factors and corresponding complexes. We elucidate the membrane-bound form of the C2 domain from human coagulation factor V (FV-C2) by characterizing its membrane binding the specific lipid-protein interactions. Employing all-atom molecular dynamics simulations and leveraging the highly mobile membrane-mimetic (HMMM) model, we observed spontaneous binding of FV-C2 to a phosphatidylserine (PS)-containing membrane within 2-25 ns across twelve independent simulations. FV-C2 interacted with the membrane through three loops (spikes 1-3), achieving a converged, stable orientation. Multiple HMMM trajectories of the spontaneous membrane binding provided extensive sampling and ample data to examine the membrane-induced effects on the conformational dynamics of C2 as well as specific lipid-protein interactions. Despite existing crystal structures representing presumed "open" and "closed" states of FV-C2, our results revealed a continuous distribution of structures between these states, with the most populated structures differing from both "open" and "closed" states observed in crystal environments. Lastly, we characterized a putative PS-specific binding site formed by K23, Q48, and S78 located in the groove enclosed by spikes 1-3 (PS-specificity pocket), suggesting a different orientation of a bound headgroup moiety compared to previous proposals based upon analysis of static crystal structures.
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Affiliation(s)
- Y. Zenmei Ohkubo
- Department of Bioinformatics, School of Life and Natural Sciences, Abdullah Gül University, Kayseri, Turkey
| | - Peter W. Radulovic
- Graduate Programs, Taneja College of Pharmacy, University of South Florida, Tampa, FL 33612, USA
| | - Albert N. Kahira
- Graduate Programs, School of Engineering, Abdullah Gül University, Kayseri, Turkey
| | - Jesper J. Madsen
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
- Center for Global Health and Infectious Diseases Research, Global and Planetary Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA
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7
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Martínez-Sánchez V, Visitación Calvo M, Viera I, Girón-Calle J, Fontecha J, Pérez-Gálvez A. Mechanisms for the interaction of the milk fat globule membrane with the plasma membrane of gut epithelial cells. Food Res Int 2023; 173:113330. [PMID: 37803640 DOI: 10.1016/j.foodres.2023.113330] [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: 05/03/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 10/08/2023]
Abstract
The milk fat globule membrane (MFGM) provides infants and adults with several health benefits. These are not derived solely from its unique composition, but also from arrangement of lipids in the MFGM that, in the case of newborns, could reach the intestine partially intact. Fluorochromes associated with lipid derivatives were used to prove a fusion process between the MFGM and the cellular membrane of differentiated Caco-2 cells. To explore the mechanism of this interaction, incubations of MFGM with Caco-2 cells were carried out in the presence of fusogenic agents or compounds that block other MFGM interaction pathways with cells. Confocal fluorescence microscopy provided visual evidence of the fusion process. Lastly, determination on the lipid profile of cells after their interaction with MFGM indicated a metabolic rearrangement of lipids leading to accumulation of triacylglycerols.
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Affiliation(s)
- Victoria Martínez-Sánchez
- Group of Chemistry and Biochemistry of Pigments, Instituto de la Grasa (CSIC), Building 46, 41013 Sevilla, Spain
| | - M Visitación Calvo
- Food Lipid Biomarkers and Health Group, Institute of Food Science Research (CSIC-UAM), 28049 Madrid, Spain
| | - I Viera
- Group of Chemistry and Biochemistry of Pigments, Instituto de la Grasa (CSIC), Building 46, 41013 Sevilla, Spain
| | - J Girón-Calle
- Food Phytochemistry Department, Instituto de la Grasa (CSIC), Building 46, 41013 Sevilla, Spain
| | - J Fontecha
- Food Lipid Biomarkers and Health Group, Institute of Food Science Research (CSIC-UAM), 28049 Madrid, Spain
| | - Antonio Pérez-Gálvez
- Group of Chemistry and Biochemistry of Pigments, Instituto de la Grasa (CSIC), Building 46, 41013 Sevilla, Spain.
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8
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Jain H, Karathanou K, Bondar AN. Graph-Based Analyses of Dynamic Water-Mediated Hydrogen-Bond Networks in Phosphatidylserine: Cholesterol Membranes. Biomolecules 2023; 13:1238. [PMID: 37627303 PMCID: PMC10452392 DOI: 10.3390/biom13081238] [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: 06/20/2023] [Revised: 08/03/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023] Open
Abstract
Phosphatidylserine lipids are anionic molecules present in eukaryotic plasma membranes, where they have essential physiological roles. The altered distribution of phosphatidylserine in cells such as apoptotic cancer cells, which, unlike healthy cells, expose phosphatidylserine, is of direct interest for the development of biomarkers. We present here applications of a recently implemented Depth-First-Search graph algorithm to dissect the dynamics of transient water-mediated lipid clusters at the interface of a model bilayer composed of 1-palmytoyl-2-oleoyl-sn-glycero-2-phosphatidylserine (POPS) and cholesterol. Relative to a reference POPS bilayer without cholesterol, in the POPS:cholesterol bilayer there is a somewhat less frequent sampling of relatively complex and extended water-mediated hydrogen-bond networks of POPS headgroups. The analysis protocol used here is more generally applicable to other lipid:cholesterol bilayers.
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Affiliation(s)
- Honey Jain
- Faculty of Physics, University of Bucharest, Atomiștilor 405, 077125 Măgurele, Romania
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | | | - Ana-Nicoleta Bondar
- Faculty of Physics, University of Bucharest, Atomiștilor 405, 077125 Măgurele, Romania
- IAS-5/INM-9, Forschungszentrum Jülich, Institute of Computational Biomedicine, Wilhelm-Johnen Straße, 52428 Jülich, Germany
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9
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Saldanha O, Schiller L, Hauser K. Calcium-induced compaction and clustering of vesicles tracked with molecular resolution. Biophys J 2023; 122:2646-2654. [PMID: 37218132 PMCID: PMC10397570 DOI: 10.1016/j.bpj.2023.05.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 04/20/2023] [Accepted: 05/18/2023] [Indexed: 05/24/2023] Open
Abstract
Theory and simulations predict the complex nature of calcium interaction with the lipid membrane. By maintaining the calcium concentrations at physiological conditions, herein we demonstrate experimentally the effect of Ca2+ in a minimalistic cell-like model. For this purpose, giant unilamellar vesicles (GUVs) with a neutral lipid DOPC are generated, and the ion-lipid interaction is observed with attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy providing molecular resolution. Firstly, Ca2+ encapsulated within the vesicle binds to the phosphate head groups of the inner leaflets and triggers vesicle compaction. This is tracked by changes in vibrational modes of the lipid groups. As the calcium concentration within the GUV increases, IR intensities change indicating vesicle dehydration and lateral compression of the membrane. Secondly, by inducing a calcium gradient across the membrane up to a ratio of 1:20, interaction between several vesicles occurs as Ca2+ can bind to the outer leaflets leading to vesicle clustering. It is observed that larger calcium gradients induce stronger interactions. These findings with an exemplary biomimetic model reveal that divalent calcium ions not only cause local changes to the lipid packing but also have macroscopic implications to initiate vesicle-vesicle interaction.
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Affiliation(s)
- Oliva Saldanha
- Department of Chemistry, University of Konstanz, Konstanz, Germany
| | - Laura Schiller
- Department of Chemistry, University of Konstanz, Konstanz, Germany
| | - Karin Hauser
- Department of Chemistry, University of Konstanz, Konstanz, Germany.
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10
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Yesylevskyy S, Martinez-Seara H, Jungwirth P. Curvature Matters: Modeling Calcium Binding to Neutral and Anionic Phospholipid Bilayers. J Phys Chem B 2023; 127:4523-4531. [PMID: 37191140 DOI: 10.1021/acs.jpcb.3c01962] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
In this work, the influence of membrane curvature on the Ca2+ binding to phospholipid bilayers is investigated by means of molecular dynamics simulations. In particular, we compared Ca2+ binding to flat, elastically buckled, or uniformly bent zwitterionic and anionic phospholipid bilayers. We demonstrate that Ca2+ ions bind preferably to the concave membrane surfaces in both types of bilayers. We also show that the membrane curvature leads to pronounced changes in Ca2+ binding including differences in free ion concentrations, lipid coordination distributions, and the patterns of ion binding to different chemical groups of lipids. Moreover, these effects differ substantially for the concave and convex membrane monolayers. Comparison between force fields with either full or scaled charges indicates that charge scaling results in reduction of the Ca2+ binding to curved phosphatidylserine bilayers, while for phosphatidylcholine membranes, calcium binds only weakly for both force fields.
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Affiliation(s)
- Semen Yesylevskyy
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 542/2, 160 00 Prague 6, Czech Republic
- Department of Physics of Biological Systems, Institute of Physics of the National Academy of Sciences of Ukraine, Nauky Avenue 46, 03038 Kyiv, Ukraine
- Receptor.AI Incorporated, 20-22 Wenlock Road, N1 7GU London, U.K
| | - Hector Martinez-Seara
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 542/2, 160 00 Prague 6, Czech Republic
| | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 542/2, 160 00 Prague 6, Czech Republic
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11
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Warner JM, An D, Stratton BS, O'Shaughnessy B. A hemifused complex is the hub in a network of pathways to membrane fusion. Biophys J 2023; 122:374-385. [PMID: 36463406 PMCID: PMC9892611 DOI: 10.1016/j.bpj.2022.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 06/25/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
Membrane fusion is a critical step for many essential processes, from neurotransmission to fertilization. For over 40 years, protein-free fusion driven by calcium or other cationic species has provided a simplified model of biological fusion, but the mechanisms remain poorly understood. Cation-mediated membrane fusion and permeation are essential in their own right to drug delivery strategies based on cell-penetrating peptides or cation-bearing lipid nanoparticles. Experimental studies suggest calcium drives anionic membranes to a hemifused intermediate that constitutes a hub in a network of pathways, but the pathway selection mechanism is unknown. Here we develop a mathematical model that identifies the network hub as a highly dynamic hemifusion complex. Multivalent cations drive expansion of this high-tension hemifusion interface between interacting vesicles during a brief transient. The fate of this interface determines the outcome, either fusion, dead-end hemifusion, or vesicle lysis. The model reproduces the unexplained finding that calcium-driven fusion of vesicles with planar membranes typically stalls at hemifusion, and we show the equilibrated hemifused state is a novel lens-shaped complex. Thus, membrane fusion kinetics follow a stochastic trajectory within a network of pathways, with outcome weightings set by a hemifused complex intermediate.
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Affiliation(s)
- Jason M Warner
- Department of Chemical Engineering, Columbia University, New York, New York
| | - Dong An
- Department of Chemical Engineering, Columbia University, New York, New York
| | | | - Ben O'Shaughnessy
- Department of Chemical Engineering, Columbia University, New York, New York.
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12
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Sule K, Anikovskiy M, Prenner EJ. Lipid Structure Determines the Differential Impact of Single Metal Additions and Binary Mixtures of Manganese, Calcium and Magnesium on Membrane Fluidity and Liposome Size. Int J Mol Sci 2023; 24:1066. [PMID: 36674581 PMCID: PMC9860990 DOI: 10.3390/ijms24021066] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 12/23/2022] [Accepted: 01/02/2023] [Indexed: 01/08/2023] Open
Abstract
Unilamellar vesicles of the biologically relevant lipids phosphatidic acid (PA) and phosphatidylserine (PS) with fully saturated (DM-) or partly unsaturated (PO-) acyl side chains were exposed to Ca, Mn and Mg in single metal additions; in equimolar mixtures or by sequential additions of one metal at a time. Laurdan generalized polarization measured the membrane fluidity, while dynamic light scattering reported liposome size changes complemented by zeta potential. All metals induced membrane rigidity and increased liposome sizes across all systems. Mn had the strongest effect overall, but Mg was comparable for DMPS. Lipid side chain architecture was important as GP values for binary mixtures were higher than expected from the sum of values for single additions added to POPS but smaller for DMPS. Sequential additions were predominantly different for Ca:Mg mixtures. Mn induced the strongest increase of liposome size in saturated lipids whereas Ca effects dominated unsaturated matrices. Binary additions induced larger sizes than the sum of single additions for POPS, but much lower changes in DMPA. The order of addition was relevant for PS systems. Thus, lipid structure determines metal effects, but their impact is modulated by other ions. Thus, metal effects may differ with the local lipid architecture and metal concentrations within cells.
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Affiliation(s)
- Kevin Sule
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Max Anikovskiy
- Department of Chemistry, Nanoscience Program, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Elmar J. Prenner
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
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13
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van Beekveld RAM, Derks MGN, Kumar R, Smid L, Maass T, Medeiros‐Silva J, Breukink E, Weingarth M. Specific Lipid Studies in Complex Membranes by Solid-State NMR Spectroscopy. Chemistry 2022; 28:e202202472. [PMID: 36098094 PMCID: PMC10092488 DOI: 10.1002/chem.202202472] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Indexed: 11/11/2022]
Abstract
Specific interactions with phospholipids are often critical for the function of proteins or drugs, but studying these interactions at high resolution remains difficult, especially in complex membranes that mimic biological conditions. In principle, molecular interactions with phospholipids could be directly probed by solid-state NMR (ssNMR). However, due to the challenge to detect specific lipids in mixed liposomes and limited spectral sensitivity, ssNMR studies of specific lipids in complex membranes are scarce. Here, by using purified biological 13 C,15 N-labeled phospholipids, we show that we can selectively detect traces of specific lipids in complex membranes. In combination with 1 H-detected ssNMR, we show that our approach provides unprecedented high-resolution insights into the mechanisms of drugs that target specific lipids. This broadly applicable approach opens new opportunities for the molecular characterization of specific lipid interactions with proteins or drugs in complex fluid membranes.
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Affiliation(s)
- Roy A. M. van Beekveld
- NMR SpectroscopyDepartment of ChemistryFaculty of ScienceUtrecht UniversityPadualaan 83584 CHUtrechtThe Netherlands
| | - Maik G. N. Derks
- NMR SpectroscopyDepartment of ChemistryFaculty of ScienceUtrecht UniversityPadualaan 83584 CHUtrechtThe Netherlands
- Membrane Biochemistry and BiophysicsDepartment of ChemistryFaculty of ScienceUtrecht UniversityPadualaan 83584 CHUtrechtThe Netherlands
| | - Raj Kumar
- NMR SpectroscopyDepartment of ChemistryFaculty of ScienceUtrecht UniversityPadualaan 83584 CHUtrechtThe Netherlands
| | - Leanna Smid
- NMR SpectroscopyDepartment of ChemistryFaculty of ScienceUtrecht UniversityPadualaan 83584 CHUtrechtThe Netherlands
| | - Thorben Maass
- NMR SpectroscopyDepartment of ChemistryFaculty of ScienceUtrecht UniversityPadualaan 83584 CHUtrechtThe Netherlands
| | - João Medeiros‐Silva
- NMR SpectroscopyDepartment of ChemistryFaculty of ScienceUtrecht UniversityPadualaan 83584 CHUtrechtThe Netherlands
- Present address: Department of ChemistryMassachusetts Institute of Technology170 Albany StreetCambridgeMA 02139USA
| | - Eefjan Breukink
- Membrane Biochemistry and BiophysicsDepartment of ChemistryFaculty of ScienceUtrecht UniversityPadualaan 83584 CHUtrechtThe Netherlands
| | - Markus Weingarth
- NMR SpectroscopyDepartment of ChemistryFaculty of ScienceUtrecht UniversityPadualaan 83584 CHUtrechtThe Netherlands
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14
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Somberg NH, Wu WW, Medeiros-Silva J, Dregni AJ, Jo H, DeGrado WF, Hong M. SARS-CoV-2 Envelope Protein Forms Clustered Pentamers in Lipid Bilayers. Biochemistry 2022; 61:2280-2294. [PMID: 36219675 PMCID: PMC9583936 DOI: 10.1021/acs.biochem.2c00464] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/26/2022] [Indexed: 11/30/2022]
Abstract
The SARS-CoV-2 envelope (E) protein is a viroporin associated with the acute respiratory symptoms of COVID-19. E forms cation-selective ion channels that assemble in the lipid membrane of the endoplasmic reticulum Golgi intermediate compartment. The channel activity of E is linked to the inflammatory response of the host cell to the virus. Like many viroporins, E is thought to oligomerize with a well-defined stoichiometry. However, attempts to determine the E stoichiometry have led to inconclusive results and suggested mixtures of oligomers whose exact nature might vary with the detergent used. Here, we employ 19F solid-state nuclear magnetic resonance and the centerband-only detection of exchange (CODEX) technique to determine the oligomeric number of E's transmembrane domain (ETM) in lipid bilayers. The CODEX equilibrium value, which corresponds to the inverse of the oligomeric number, indicates that ETM assembles into pentamers in lipid bilayers, without any detectable fraction of low-molecular-weight oligomers. Unexpectedly, at high peptide concentrations and in the presence of the lipid phosphatidylinositol, the CODEX data indicate that more than five 19F spins are within a detectable distance of about 2 nm, suggesting that the ETM pentamers cluster in the lipid bilayer. Monte Carlo simulations that take into account peptide-peptide and peptide-lipid interactions yielded pentamer clusters that reproduced the CODEX data. This supramolecular organization is likely important for E-mediated virus assembly and budding and for the channel function of the protein.
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Affiliation(s)
- Noah H Somberg
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts02139, United States
| | - Westley W Wu
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts02139, United States
| | - João Medeiros-Silva
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts02139, United States
| | - Aurelio J Dregni
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts02139, United States
| | - Hyunil Jo
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 555 Mission Bay Blvd. South, San Francisco, California94158, United States
| | - William F DeGrado
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 555 Mission Bay Blvd. South, San Francisco, California94158, United States
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts02139, United States
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15
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You X, Thakur N, Ray AP, Eddy MT, Baiz CR. A comparative study of interfacial environments in lipid nanodiscs and vesicles. BIOPHYSICAL REPORTS 2022; 2. [PMID: 36176716 PMCID: PMC9518727 DOI: 10.1016/j.bpr.2022.100066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Membrane protein conformations and dynamics are driven by the protein-lipid interactions occurring within the local environment of the membrane. These environments remain challenging to accurately capture in structural and biophysical experiments using bilayers. Consequently, there is an increasing need for realistic cell-membrane mimetics for in vitro studies. Lipid nanodiscs provide certain advantages over vesicles for membrane protein studies. Nanodiscs are increasingly used for structural and spectroscopic characterization of membrane proteins. Despite the common use of nanodiscs, the interfacial environments of lipids confined to a ~10-nm diameter area have remained relatively underexplored. Here, we use ultrafast two-dimensional infrared spectroscopy and temperature-dependent infrared absorption measurements of the ester carbonyls to compare the interfacial hydrogen bond structure and dynamics in lipid nanodiscs of varying lipid compositions and sizes with ~100-nm vesicles. We examine the effects of lipid composition and nanodisc size. We found that nanodiscs and vesicles share largely similar lipid-water H-bond environments and interfacial dynamics. Differences in measured enthalpies of H-bonding suggest that H-bond dynamics in nanodiscs are modulated by the interaction between the annular lipids and the scaffold protein.
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16
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Zubaite G, Hindley JW, Ces O, Elani Y. Dynamic Reconfiguration of Subcompartment Architectures in Artificial Cells. ACS NANO 2022; 16:9389-9400. [PMID: 35695383 PMCID: PMC9245354 DOI: 10.1021/acsnano.2c02195] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 04/27/2022] [Indexed: 06/01/2023]
Abstract
Artificial cells are minimal structures constructed from biomolecular building blocks designed to mimic cellular processes, behaviors, and architectures. One near-ubiquitous feature of cellular life is the spatial organization of internal content. We know from biology that organization of content (including in membrane-bound organelles) is linked to cellular functions and that this feature is dynamic: the presence, location, and degree of compartmentalization changes over time. Vesicle-based artificial cells, however, are not currently able to mimic this fundamental cellular property. Here, we describe an artificial cell design strategy that addresses this technological bottleneck. We create a series of artificial cell architectures which possess multicompartment assemblies localized either on the inner or on the outer surface of the artificial cell membrane. Exploiting liquid-liquid phase separation, we can also engineer spatially segregated regions of condensed subcompartments attached to the cell surface, aligning with coexisting membrane domains. These structures can sense changes in environmental conditions and respond by reversibly transitioning from condensed multicompartment layers on the membrane surface to a dispersed state in the cell lumen, mimicking the dynamic compartmentalization found in biological cells. Likewise, we engineer exosome-like subcompartments that can be released to the environment. We can achieve this by using two types of triggers: chemical (addition of salts) and mechanical (by pulling membrane tethers using optical traps). These approaches allow us to control the compartmentalization state of artificial cells on population and single-cell levels.
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Affiliation(s)
- Greta Zubaite
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London W12
0BZ, United Kingdom
- Department
of Chemical Engineering, Imperial College
London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - James W. Hindley
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London W12
0BZ, United Kingdom
- Institute
of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London W12
0BZ, United Kingdom
- fabriCELL,
Molecular Sciences Research Hub, Imperial
College London, 82 Wood Lane, London W12
0BZ, United Kingdom
| | - Oscar Ces
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London W12
0BZ, United Kingdom
- Institute
of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London W12
0BZ, United Kingdom
- fabriCELL,
Molecular Sciences Research Hub, Imperial
College London, 82 Wood Lane, London W12
0BZ, United Kingdom
| | - Yuval Elani
- fabriCELL,
Molecular Sciences Research Hub, Imperial
College London, 82 Wood Lane, London W12
0BZ, United Kingdom
- Department
of Chemical Engineering, Imperial College
London, Exhibition Road, London SW7 2AZ, United Kingdom
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17
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The lung surfactant activity probed with molecular dynamics simulations. Adv Colloid Interface Sci 2022; 304:102659. [PMID: 35421637 DOI: 10.1016/j.cis.2022.102659] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 03/18/2022] [Accepted: 03/31/2022] [Indexed: 01/17/2023]
Abstract
The surface of pulmonary alveolar subphase is covered with a mixture of lipids and proteins. This lung surfactant plays a crucial role in lung functioning. It shows a complex phase behavior which can be altered by the interaction with third molecules such as drugs or pollutants. For studying multicomponent biological systems, it is of interest to couple experimental approach with computational modelling yielding atomic-scale information. Simple two, three, or four-component model systems showed to be useful for getting more insight in the interaction between lipids, lipids and proteins or lipids and proteins with drugs and impurities. These systems were studied theoretically using molecular dynamic simulations and experimentally by means of the Langmuir technique. A better understanding of the structure and behavior of lung surfactants obtained from this research is relevant for developing new synthetic surfactants for efficient therapies, and may contribute to public health protection.
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18
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Balantič K, Weiss VU, Allmaier G, Kramar P. Calcium ion effect on phospholipid bilayers as cell membrane analogues. Bioelectrochemistry 2022; 143:107988. [PMID: 34763170 DOI: 10.1016/j.bioelechem.2021.107988] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/22/2021] [Accepted: 10/23/2021] [Indexed: 12/14/2022]
Abstract
Ion attachment can modify stability and structure of phospholipid bilayers. Of particular importance is the interaction of phospholipids with divalent cations, such as calcium ions playing an important role in numerous cellular processes. The aim of our study was to determine effects of calcium ions on phospholipid membranes employing two cell membrane analogues, liposomes and planar lipid bilayers, and for the first time the combination of two instrumental setups: gas-phase electrophoresis (nES GEMMA instrumentation) and electrical (capacitance and resistance) measurements. Liposomes and planar lipid bilayers consisted of phosphatidylcholine, cholesterol and phosphatidylethanolamine. Liposomes were prepared from dried lipid films via hydration while planar lipid bilayers were formed using a Mueller-Rudin method. Calcium ions were added to membranes from higher concentrated stock solutions. Changes in phospholipid bilayer properties due to calcium presence were observed for both studied cell membrane analogues. Changes in liposome size were observed, which might either be related to tighter packing of phospholipids in the bilayer or local distortions of the membrane. Likewise, a measurable change in planar lipid bilayer resistance and capacitance was observed in the presence of calcium ions, which can be due to an increased rigidity and tighter packing of the lipid molecules in the bilayer.
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Affiliation(s)
- Katja Balantič
- University of Ljubljana, Faculty of Electrical Engineering, Slovenia
| | - Victor U Weiss
- Institute of Chemical Technologies and Analytics, TU Wien (Vienna University of Technology), Vienna, Austria
| | - Günter Allmaier
- Institute of Chemical Technologies and Analytics, TU Wien (Vienna University of Technology), Vienna, Austria
| | - Peter Kramar
- University of Ljubljana, Faculty of Electrical Engineering, Slovenia.
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19
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Cheng D, Li H, Hu S, Zhao T. Structural effects of zinc on phosphatidylserine-containing lipid membranes: kinetic analysis of membrane reorganization. NEW J CHEM 2022. [DOI: 10.1039/d2nj00515h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Zinc induces reorganization of phosphatidylserine-containing lipid membranes.
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Affiliation(s)
- Danling Cheng
- College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, 333 Longteng Road, Shanghai, 201620, China
| | - Hewen Li
- College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, 333 Longteng Road, Shanghai, 201620, China
| | - Shipeng Hu
- College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, 333 Longteng Road, Shanghai, 201620, China
| | - Tao Zhao
- College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, 333 Longteng Road, Shanghai, 201620, China
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20
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Ohkubo YZ, Madsen JJ. Uncovering Membrane-Bound Models of Coagulation Factors by Combined Experimental and Computational Approaches. Thromb Haemost 2021; 121:1122-1137. [PMID: 34214998 PMCID: PMC8432591 DOI: 10.1055/s-0040-1722187] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In the life sciences, including hemostasis and thrombosis, methods of structural biology have become indispensable tools for shedding light on underlying mechanisms that govern complex biological processes. Advancements of the relatively young field of computational biology have matured to a point where it is increasingly recognized as trustworthy and useful, in part due to their high space–time resolution that is unparalleled by most experimental techniques to date. In concert with biochemical and biophysical approaches, computational studies have therefore proven time and again in recent years to be key assets in building or suggesting structural models for membrane-bound forms of coagulation factors and their supramolecular complexes on membrane surfaces where they are activated. Such endeavors and the proposed models arising from them are of fundamental importance in describing and understanding the molecular basis of hemostasis under both health and disease conditions. We summarize the body of work done in this important area of research to drive forward both experimental and computational studies toward new discoveries and potential future therapeutic strategies.
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Affiliation(s)
- Y Zenmei Ohkubo
- Department of Bioinformatics, School of Life and Natural Sciences, Abdullah Gül University, Kayseri, Turkey
| | - Jesper J Madsen
- Global and Planetary Health, College of Public Health, University of South Florida, Tampa, Florida, United States
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21
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The Impact of Extracellular Ca 2+ and Nanosecond Electric Pulses on Sensitive and Drug-Resistant Human Breast and Colon Cancer Cells. Cancers (Basel) 2021; 13:cancers13133216. [PMID: 34203184 PMCID: PMC8268418 DOI: 10.3390/cancers13133216] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/15/2021] [Accepted: 06/23/2021] [Indexed: 01/16/2023] Open
Abstract
Simple Summary The drug resistance phenomenon in cancer constantly induces problems in therapeutic protocols. Pulsed electric fields (PEFs) seem to be a promising method in drug molecule delivery. Here we have proved that electroporation supported by calcium ions can alternate the activity of drug resistance proteins. Our results indicated that MDR1 expression is not significantly modified by nanosecond electroporation in multidrug-resistant cells. However, PEF significantly inhibited MDR1 activity and cell viability when combined with calcium ions. Abstract (1) Background: Calcium electroporation (CaEP) is based on the application of electrical pulses to permeabilize cells (electroporation) and allow cytotoxic doses of calcium to enter the cell. (2) Methods: In this work, we have used doxorubicin-resistant (DX) and non-resistant models of human breast cancer (MCF-7/DX, MCF-7/WT) and colon cancer cells (LoVo, LoVo/DX), and investigated the susceptibility of the cells to extracellular Ca2+ and electric fields in the 20 ns–900 ns pulse duration range. (3) Results: We have observed that colon cancer cells were less susceptible to PEF than breast cancer cells. An extracellular Ca2+ (2 mM) with PEF was more disruptive for DX-resistant cells. The expression of glycoprotein P (MDR1, P-gp) as a drug resistance marker was detected by the immunofluorescent (CLSM) method and rhodamine-123 efflux as an MDR1 activity. MDR1 expression was not significantly modified by nanosecond electroporation in multidrug-resistant cells, but a combination with calcium ions significantly inhibited MDR1 activity and cell viability. (4) Conclusions: We believe that PEF with calcium ions can reduce drug resistance by inhibiting drug efflux activity. This phenomenon of MDR mechanism disruption seems promising in anticancer protocols.
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22
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Ghaed-Sharaf T, Ghatee MH. Synergistic aggregation of the ibuprofenate anion and a a double-strand imidazolium cation into vesicles for drug delivery: a simulation study. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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23
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Bernier SC, Millette MA, Roy S, Cantin L, Coutinho A, Salesse C. Structural information and membrane binding of truncated RGS9-1 Anchor Protein and its C-terminal hydrophobic segment. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183566. [PMID: 33453187 DOI: 10.1016/j.bbamem.2021.183566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 12/22/2020] [Accepted: 01/10/2021] [Indexed: 01/19/2023]
Abstract
Visual phototransduction takes place in photoreceptor cells. Light absorption by rhodopsin leads to the activation of transducin as a result of the exchange of its GDP for GTP. The GTP-bound ⍺-subunit of transducin then activates phosphodiesterase (PDE), which in turn hydrolyzes cGMP leading to photoreceptor hyperpolarization. Photoreceptors return to the dark state upon inactivation of these proteins. In particular, PDE is inactivated by the protein complex R9AP/RGS9-1/Gβ5. R9AP (RGS9-1 anchor protein) is responsible for the membrane anchoring of this protein complex to photoreceptor outer segment disk membranes most likely by the combined involvement of its C-terminal hydrophobic domain as well as other types of interactions. This study thus aimed to gather information on the structure and membrane binding of the C-terminal hydrophobic segment of R9AP as well as of truncated R9AP (without its C-terminal domain, R9AP∆TM). Circular dichroism and infrared spectroscopic measurements revealed that the secondary structure of R9AP∆TM mainly includes ⍺-helical structural elements. Moreover, intrinsic fluorescence measurements of native R9AP∆TM and individual mutants lacking one tryptophan demonstrated that W79 is more buried than W173 but that they are both located in a hydrophobic environment. This method also revealed that membrane binding of R9AP∆TM does not involve regions near its tryptophan residues, while infrared spectroscopy validated its binding to lipid vesicles. Additional fluorescence measurements showed that the C-terminal segment of R9AP is membrane embedded. Maximum insertion pressure and synergy data using Langmuir monolayers suggest that interactions with specific phospholipids could be involved in the membrane binding of R9AP∆TM.
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Affiliation(s)
- Sarah C Bernier
- CUO-Recherche, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de Médecine, and Regroupement Stratégique PROTEO, Université Laval, Québec, Québec, Canada
| | - Marc-Antoine Millette
- CUO-Recherche, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de Médecine, and Regroupement Stratégique PROTEO, Université Laval, Québec, Québec, Canada
| | - Sarah Roy
- CUO-Recherche, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de Médecine, and Regroupement Stratégique PROTEO, Université Laval, Québec, Québec, Canada
| | - Line Cantin
- CUO-Recherche, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de Médecine, and Regroupement Stratégique PROTEO, Université Laval, Québec, Québec, Canada
| | - Ana Coutinho
- iBB-Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal; Department of Chemistry and Biochemistry, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Christian Salesse
- CUO-Recherche, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de Médecine, and Regroupement Stratégique PROTEO, Université Laval, Québec, Québec, Canada.
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24
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Stefanski KM, Russell CM, Westerfield JM, Lamichhane R, Barrera FN. PIP 2 promotes conformation-specific dimerization of the EphA2 membrane region. J Biol Chem 2021; 296:100149. [PMID: 33277361 PMCID: PMC7900517 DOI: 10.1074/jbc.ra120.016423] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/18/2020] [Accepted: 12/04/2020] [Indexed: 12/27/2022] Open
Abstract
The impact of the EphA2 receptor on cancer malignancy hinges on the two different ways it can be activated. EphA2 induces antioncogenic signaling after ligand binding, but ligand-independent activation of EphA2 is pro-oncogenic. It is believed that the transmembrane (TM) domain of EphA2 adopts two alternate conformations in the ligand-dependent and the ligand-independent states. However, it is poorly understood how the difference in TM helical crossing angles found in the two conformations impacts the activity and regulation of EphA2. We devised a method that uses hydrophobic matching to stabilize two conformations of a peptide comprising the EphA2 TM domain and a portion of the intracellular juxtamembrane (JM) segment. The two conformations exhibit different TM crossing angles, resembling the ligand-dependent and ligand-independent states. We developed a single-molecule technique using styrene maleic acid lipid particles to measure dimerization in membranes. We observed that the signaling lipid PIP2 promotes TM dimerization, but only in the small crossing angle state, which we propose corresponds to the ligand-independent conformation. In this state the two TMs are almost parallel, and the positively charged JM segments are expected to be close to each other, causing electrostatic repulsion. The mechanism PIP2 uses to promote dimerization might involve alleviating this repulsion due to its high density of negative charges. Our data reveal a conformational coupling between the TM and JM regions and suggest that PIP2 might directly exert a regulatory effect on EphA2 activation in cells that is specific to the ligand-independent conformation of the receptor.
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Affiliation(s)
- Katherine M Stefanski
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, USA
| | - Charles M Russell
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, USA
| | - Justin M Westerfield
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, USA
| | - Rajan Lamichhane
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, USA.
| | - Francisco N Barrera
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, USA.
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25
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Javanainen M, Hua W, Tichacek O, Delcroix P, Cwiklik L, Allen HC. Structural Effects of Cation Binding to DPPC Monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:15258-15269. [PMID: 33296215 DOI: 10.1021/acs.langmuir.0c02555] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ions at the two sides of the plasma membrane maintain the transmembrane potential, participate in signaling, and affect the properties of the membrane itself. The extracellular leaflet is particularly enriched in phosphatidylcholine lipids and under the influence of Na+, Ca2+, and Cl- ions. In this work, we combined molecular dynamics simulations performed using state-of-the-art models with vibrational sum frequency generation (VSFG) spectroscopy to study the effects of these key ions on the structure of dipalmitoylphosphatidylcholine. We used lipid monolayers as a proxy for membranes, as this approach enabled a direct comparison between simulation and experiment. We find that the effects of Na+ are minor. Ca2+, on the other hand, strongly affects the lipid headgroup conformations and induces a tighter packing of lipids, thus promoting the liquid condensed phase. It does so by binding to both the phosphate and carbonyl oxygens via direct and water-mediated binding modes, the ratios of which depend on the monolayer packing. Clustering analysis performed on simulation data revealed that changes in area per lipid or CaCl2 concentration both affect the headgroup conformations, yet their effects are anticorrelated. Cations at the monolayer surface also attract Cl-, which at large CaCl2 concentrations penetrates deep to the monolayer. This phenomenon coincides with a radical change in the VSFG spectra of the phosphate group, thus indicating the emergence of a new binding mode.
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Affiliation(s)
- Matti Javanainen
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 542/2, 160 00 Prague 6, Czech Republic
| | - Wei Hua
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Ondrej Tichacek
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 542/2, 160 00 Prague 6, Czech Republic
| | - Pauline Delcroix
- J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejskova 3, 18223 Prague 8, Czech Republic
| | - Lukasz Cwiklik
- J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejskova 3, 18223 Prague 8, Czech Republic
| | - Heather C Allen
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
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26
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Unruh C, Van Bavel N, Anikovskiy M, Prenner EJ. Benefits and Detriments of Gadolinium from Medical Advances to Health and Ecological Risks. Molecules 2020; 25:molecules25235762. [PMID: 33297578 PMCID: PMC7730697 DOI: 10.3390/molecules25235762] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 11/30/2020] [Accepted: 12/04/2020] [Indexed: 12/17/2022] Open
Abstract
Gadolinium (Gd)-containing chelates have been established as diagnostics tools. However, extensive use in magnetic resonance imaging has led to increased Gd levels in industrialized parts of the world, adding to natural occurrence and causing environmental and health concerns. A vast amount of data shows that metal may accumulate in the human body and its deposition has been detected in organs such as brain and liver. Moreover, the disease nephrogenic systemic fibrosis has been linked to increased Gd3+ levels. Investigation of Gd3+ effects at the cellular and molecular levels mostly revolves around calcium-dependent proteins, since Gd3+ competes with calcium due to their similar size; other reports focus on interaction of Gd3+ with nucleic acids and carbohydrates. However, little is known about Gd3+ effects on membranes; yet some results suggest that Gd3+ interacts strongly with biologically-relevant lipids (e.g., brain membrane constituents) and causes serious structural changes including enhanced membrane rigidity and propensity for lipid fusion and aggregation at much lower concentrations than other ions, both toxic and essential. This review surveys the impact of the anthropogenic use of Gd emphasizing health risks and discussing debilitating effects of Gd3+ on cell membrane organization that may lead to deleterious health consequences.
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Affiliation(s)
- Colin Unruh
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada; (C.U.); (N.V.B.)
| | - Nicolas Van Bavel
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada; (C.U.); (N.V.B.)
| | - Max Anikovskiy
- Department of Chemistry, University of Calgary, Calgary, AB T2N 1N4, Canada
- Correspondence: (M.A.); (E.J.P.)
| | - Elmar J. Prenner
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada; (C.U.); (N.V.B.)
- Correspondence: (M.A.); (E.J.P.)
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27
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Sahoo A, Matysiak S. Microscopic Picture of Calcium-Assisted Lipid Demixing and Membrane Remodeling Using Multiscale Simulations. J Phys Chem B 2020; 124:7327-7335. [PMID: 32786720 DOI: 10.1021/acs.jpcb.0c03067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The specificity of anionic phospholipids-calcium ion interaction and lipid demixing has been established as a key regulatory mechanism in several cellular signaling processes. The mechanism and implications of this calcium-assisted demixing have not been elucidated from a microscopic point of view. Here, we present an overview of atomic interactions between calcium and phospholipids that can drive nonideal mixing of lipid molecules in a model lipid bilayer composed of zwitterionic (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)) and anionic (1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-l-serine (POPS)) lipids with computer simulations at multiple resolutions. Lipid nanodomain formation and growth were driven by calcium-enabled lipid bridging of the charged phosphatidylserine (PS) headgroups, which were favored against inter-POPS dipole interactions. Consistent with several experimental studies of calcium-associated membrane sculpting, our analyses also suggest modifications in local membrane curvature and cross-leaflet couplings as a response to such induced lateral heterogeneity. In addition, reverse mapping to a complementary atomistic description revealed structural insights in the presence of anionic nanodomains, at timescales not accessed by previous computational studies. This work bridges information across multiple scales to reveal a mechanistic picture of calcium ion's impact on membrane biophysics.
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Affiliation(s)
- Abhilash Sahoo
- Biophysics Program, Institute of Physical Science and Technology, University of Maryland, College Park, Maryland 20742, United States
| | - Silvina Matysiak
- Biophysics Program, Institute of Physical Science and Technology, University of Maryland, College Park, Maryland 20742, United States.,Fischell Department of Bioengineering, University of Maryland, College Park, Maryland 20742, United States
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28
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Cruz MAE, Ferreira CR, Tovani CB, de Oliveira FA, Bolean M, Caseli L, Mebarek S, Millán JL, Buchet R, Bottini M, Ciancaglini P, Paula Ramos A. Phosphatidylserine controls calcium phosphate nucleation and growth on lipid monolayers: A physicochemical understanding of matrix vesicle-driven biomineralization. J Struct Biol 2020; 212:107607. [PMID: 32858148 DOI: 10.1016/j.jsb.2020.107607] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 08/15/2020] [Accepted: 08/19/2020] [Indexed: 12/12/2022]
Abstract
Bone biomineralization is an exquisite process by which a hierarchically organized mineral matrix is formed. Growing evidence has uncovered the involvement of one class of extracellular vesicles, named matrix vesicles (MVs), in the formation and delivery of the first mineral nuclei to direct collagen mineralization. MVs are released by mineralization-competent cells equipped with a specific biochemical machinery to initiate mineral formation. However, little is known about the mechanisms by which MVs can trigger this process. Here, we present a combination of in situ investigations and ex vivo analysis of MVs extracted from growing-femurs of chicken embryos to investigate the role played by phosphatidylserine (PS) in the formation of mineral nuclei. By using self-assembled Langmuir monolayers, we reconstructed the nucleation core - a PS-enriched motif thought to trigger mineral formation in the lumen of MVs. In situ infrared spectroscopy of Langmuir monolayers and ex situ analysis by transmission electron microscopy evidenced that mineralization was achieved in supersaturated solutions only when PS was present. PS nucleated amorphous calcium phosphate that converted into biomimetic apatite. By using monolayers containing lipids extracted from native MVs, mineral formation was also evidenced in a manner that resembles the artificial PS-enriched monolayers. PS-enrichment in lipid monolayers creates nanodomains for local increase of supersaturation, leading to the nucleation of ACP at the interface through a multistep process. We posited that PS-mediated nucleation could be a predominant mechanism to produce the very first mineral nuclei during MV-driven bone/cartilage biomineralization.
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Affiliation(s)
- Marcos A E Cruz
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, FFCLRP - Universidade de São Paulo - Departamento de Química, Brazil
| | - Claudio R Ferreira
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, FFCLRP - Universidade de São Paulo - Departamento de Química, Brazil
| | - Camila B Tovani
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, FFCLRP - Universidade de São Paulo - Departamento de Química, Brazil
| | | | - Maytê Bolean
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, FFCLRP - Universidade de São Paulo - Departamento de Química, Brazil
| | - Luciano Caseli
- Institute of Environmental, Chemical and Pharmaceutical Sciences - Federal University of Sao Paulo, Brazil
| | - Saida Mebarek
- Universite de Lyon, ICBMS UMR 5246 CNRS, Villeurbanne, France
| | - José Luis Millán
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Rene Buchet
- Universite de Lyon, ICBMS UMR 5246 CNRS, Villeurbanne, France
| | - Massimo Bottini
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA; Department of Experimental Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Pietro Ciancaglini
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, FFCLRP - Universidade de São Paulo - Departamento de Química, Brazil.
| | - Ana Paula Ramos
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, FFCLRP - Universidade de São Paulo - Departamento de Química, Brazil.
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29
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Ali Doosti B, Fjällborg D, Kustanovich K, Jesorka A, Cans AS, Lobovkina T. Generation of interconnected vesicles in a liposomal cell model. Sci Rep 2020; 10:14040. [PMID: 32820180 PMCID: PMC7441142 DOI: 10.1038/s41598-020-70562-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 06/08/2020] [Indexed: 12/04/2022] Open
Abstract
We introduce an experimental method based upon a glass micropipette microinjection technique for generating a multitude of interconnected vesicles (IVs) in the interior of a single giant unilamellar phospholipid vesicle (GUV) serving as a cell model system. The GUV membrane, consisting of a mixture of soybean polar lipid extract and anionic phosphatidylserine, is adhered to a multilamellar lipid vesicle that functions as a lipid reservoir. Continuous IV formation was achieved by bringing a micropipette in direct contact with the outer GUV surface and subjecting it to a localized stream of a Ca2+ solution from the micropipette tip. IVs are rapidly and sequentially generated and inserted into the GUV interior and encapsulate portions of the micropipette fluid content. The IVs remain connected to the GUV membrane and are interlinked by short lipid nanotubes and resemble beads on a string. The vesicle chain-growth from the GUV membrane is maintained for as long as there is the supply of membrane material and Ca2+ solution, and the size of the individual IVs is controlled by the diameter of the micropipette tip. We also demonstrate that the IVs can be co-loaded with high concentrations of neurotransmitter and protein molecules and displaying a steep calcium ion concentration gradient across the membrane. These characteristics are analogous to native secretory vesicles and could, therefore, serve as a model system for studying secretory mechanisms in biological systems.
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Affiliation(s)
- Baharan Ali Doosti
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 9, 412 96, Göteborg, Sweden
| | - Daniel Fjällborg
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 9, 412 96, Göteborg, Sweden
| | - Kiryl Kustanovich
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 9, 412 96, Göteborg, Sweden
| | - Aldo Jesorka
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 9, 412 96, Göteborg, Sweden
| | - Ann-Sofie Cans
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 9, 412 96, Göteborg, Sweden
| | - Tatsiana Lobovkina
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 9, 412 96, Göteborg, Sweden.
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30
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Redpath GMI, Betzler VM, Rossatti P, Rossy J. Membrane Heterogeneity Controls Cellular Endocytic Trafficking. Front Cell Dev Biol 2020; 8:757. [PMID: 32850860 PMCID: PMC7419583 DOI: 10.3389/fcell.2020.00757] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 07/20/2020] [Indexed: 12/21/2022] Open
Abstract
Endocytic trafficking relies on highly localized events in cell membranes. Endocytosis involves the gathering of protein (cargo/receptor) at distinct plasma membrane locations defined by specific lipid and protein compositions. Simultaneously, the molecular machinery that drives invagination and eventually scission of the endocytic vesicle assembles at the very same place on the inner leaflet of the membrane. It is membrane heterogeneity - the existence of specific lipid and protein domains in localized regions of membranes - that creates the distinct molecular identity required for an endocytic event to occur precisely when and where it is required rather than at some random location within the plasma membrane. Accumulating evidence leads us to believe that the trafficking fate of internalized proteins is sealed following endocytosis, as this distinct membrane identity is preserved through the endocytic pathway, upon fusion of endocytic vesicles with early and sorting endosomes. In fact, just like at the plasma membrane, multiple domains coexist at the surface of these endosomes, regulating local membrane tubulation, fission and sorting to recycling pathways or to the trans-Golgi network via late endosomes. From here, membrane heterogeneity ensures that fusion events between intracellular vesicles and larger compartments are spatially regulated to promote the transport of cargoes to their intracellular destination.
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Affiliation(s)
- Gregory M I Redpath
- Department of Biochemistry, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,The ANZAC Research Institute, Concord Repatriation General Hospital, Concord, NSW, Australia
| | - Verena M Betzler
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.,Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Kreuzlingen, Switzerland
| | - Pascal Rossatti
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.,Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Kreuzlingen, Switzerland
| | - Jérémie Rossy
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Kreuzlingen, Switzerland.,Department of Biology, University of Konstanz, Konstanz, Germany
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31
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Gadolinium Complexes as Contrast Agent for Cellular NMR Spectroscopy. Int J Mol Sci 2020; 21:ijms21114042. [PMID: 32516957 PMCID: PMC7312942 DOI: 10.3390/ijms21114042] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 05/27/2020] [Accepted: 06/03/2020] [Indexed: 02/07/2023] Open
Abstract
Aqua Gd3+ and Gd-DOTA (gadolinium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacete) complexes were studied as a contrast agent in cellular NMR (nuclear magnetic resonance) spectroscopy for distinguishing between intracellular and extracellular spaces. The contrast agents for this purpose should provide strong paramagnetic relaxation enhancement and localize in the extracellular space without disturbing biological functions. Cell membrane permeability to Gd complexes was evaluated from the concentrations of gadolinium complexes in the inside and outside of E. coli cells measured by the 1H-NMR relaxation. The site-specific binding of the complexes to E. coli cells was also analyzed by high-resolution solid-state 13C-NMR. The aqua Gd3+ complex did not enhance T1 relaxation in proportion to the amount of added Gd3+. This Gd3+ concentration dependence and the 13C-NMR indicated that its strong cytotoxicity should be due to the binding of the paramagnetic ions to cellular components especially at the lipid membranes. In contrast, Gd-DOTA stayed in the solution states and enhanced relaxation in proportion to the added amount. This agent exhibited strong T1 contrast between the intra- and extracellular spaces by a factor of ten at high concentrations under which the cells were viable over a long experimental time of days. These properties make Gd-DOTA suitable for selectively contrasting the living cellular space in NMR spectroscopy primarily owing to its weak interaction with cellular components.
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32
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Valentine ML, Cardenas AE, Elber R, Baiz CR. Calcium-Lipid Interactions Observed with Isotope-Edited Infrared Spectroscopy. Biophys J 2020; 118:2694-2702. [PMID: 32362342 DOI: 10.1016/j.bpj.2020.04.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 03/20/2020] [Accepted: 04/10/2020] [Indexed: 01/17/2023] Open
Abstract
Calcium ions bind to lipid membranes containing anionic lipids; however, characterizing the specific ion-lipid interactions in multicomponent membranes has remained challenging because it requires nonperturbative lipid-specific probes. Here, using a combination of isotope-edited infrared spectroscopy and molecular dynamics simulations, we characterize the effects of a physiologically relevant (2 mM) Ca2+ concentration on zwitterionic phosphatidylcholine and anionic phosphatidylserine lipids in mixed lipid membranes. We show that Ca2+ alters hydrogen bonding between water and lipid headgroups by forming a coordination complex involving the lipid headgroups and water. These interactions distort interfacial water orientations and prevent hydrogen bonding with lipid ester carbonyls. We demonstrate, experimentally, that these effects are more pronounced for the anionic phosphatidylserine lipids than for zwitterionic phosphatidylcholine lipids in the same membrane.
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Affiliation(s)
- Mason L Valentine
- Department of Chemistry, University of Texas at Austin, Austin, Texas
| | - Alfredo E Cardenas
- Department of Chemistry, University of Texas at Austin, Austin, Texas; Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, Texas
| | - Ron Elber
- Department of Chemistry, University of Texas at Austin, Austin, Texas; Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, Texas
| | - Carlos R Baiz
- Department of Chemistry, University of Texas at Austin, Austin, Texas.
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33
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Abstract
The interactions between lipids and proteins are one of the most fundamental processes in living organisms, responsible for critical cellular events ranging from replication, cell division, signaling, and movement. Enabling the central coupling responsible for maintaining the functionality of the breadth of proteins, receptors, and enzymes that find their natural home in biological membranes, the fundamental mechanisms of recognition of protein for lipid, and vice versa, have been a focal point of biochemical and biophysical investigations for many decades. Complexes of lipids and proteins, such as the various lipoprotein factions, play central roles in the trafficking of important proteins, small molecules and metabolites and are often implicated in disease states. Recently an engineered lipoprotein particle, termed the nanodisc, a modified form of the human high density lipoprotein fraction, has served as a membrane mimetic for the investigation of membrane proteins and studies of lipid-protein interactions. In this review, we summarize the current knowledge regarding this self-assembling lipid-protein complex and provide examples for its utility in the investigation of a large number of biological systems.
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34
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Vasconcelos JM, Zen F, Angione MD, Cullen RJ, Santos-Martinez MJ, Colavita PE. Understanding the Carbon–Bio Interface: Influence of Surface Chemistry and Buffer Composition on the Adsorption of Phospholipid Liposomes at Carbon Surfaces. ACS APPLIED BIO MATERIALS 2020; 3:997-1007. [DOI: 10.1021/acsabm.9b01011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | - Federico Zen
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
| | | | - Ronan J. Cullen
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
| | - Maria J. Santos-Martinez
- School of Pharmacy and Pharmaceutical Sciences, School of Medicine and Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
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35
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Melcr J, Ferreira TM, Jungwirth P, Ollila OHS. Improved Cation Binding to Lipid Bilayers with Negatively Charged POPS by Effective Inclusion of Electronic Polarization. J Chem Theory Comput 2019; 16:738-748. [PMID: 31762275 DOI: 10.1021/acs.jctc.9b00824] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Phosphatidylserine (PS) lipids are important signaling molecules and the most common negatively charged lipids in eukaryotic membranes. The signaling can be often regulated by calcium, but its interactions with PS headgroups are not fully understood. Classical molecular dynamics (MD) simulations can potentially give detailed description of lipid-ion interactions, but the results strongly depend on the used force field. Here, we apply the electronic continuum correction (ECC) to the Amber Lipid17 parameters of 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-l-serine (POPS) lipid to improve its interactions with K+, Na+, and Ca2+ ions. The partial charges of the headgroup, glycerol backbone, and carbonyls of POPS, bearing a unit negative charge, were scaled with a factor of 0.75, derived for monovalent ions, and the Lennard-Jones σ parameters of the same segments were scaled with a factor of 0.89. The resulting ECC-POPS model gives more realistic interactions with Na+ and Ca2+ cations than the original Amber Lipid17 parameters when validated using headgroup order parameters and the "electrometer concept". In ECC-lipids simulations, populations of complexes of Ca2+ cations with more than two PS lipids are negligible, and interactions of Ca2+ cations with only carboxylate groups are twice more likely than with only phosphate groups, while interactions with carbonyls almost entirely involve other groups as well. Our results pave the way for more realistic MD simulations of biomolecular systems with anionic membranes, allowing signaling processes involving PS and Ca2+ to be elucidated.
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Affiliation(s)
- Josef Melcr
- Institute of Organic Chemistry and Biochemistry , Czech Academy of Sciences , Flemingovo nám. 542/2 , CZ-16610 Prague 6 , Czech Republic.,Groningen Biomolecular Sciences and Biotechnology Institute and The Zernike Institute for Advanced Materials , University of Groningen , 9747 AG Groningen , The Netherlands
| | - Tiago M Ferreira
- NMR Group-Institut for Physics , Martin-Luther University Halle-Wittenberg , 06120 Halle , Germany
| | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry , Czech Academy of Sciences , Flemingovo nám. 542/2 , CZ-16610 Prague 6 , Czech Republic
| | - O H Samuli Ollila
- Institute of Organic Chemistry and Biochemistry , Czech Academy of Sciences , Flemingovo nám. 542/2 , CZ-16610 Prague 6 , Czech Republic.,Institute of Biotechnology , University of Helsinki , Helsinki FI-00014 , Finland
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36
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Antila H, Buslaev P, Favela-Rosales F, Ferreira TM, Gushchin I, Javanainen M, Kav B, Madsen JJ, Melcr J, Miettinen MS, Määttä J, Nencini R, Ollila OHS, Piggot TJ. Headgroup Structure and Cation Binding in Phosphatidylserine Lipid Bilayers. J Phys Chem B 2019; 123:9066-9079. [DOI: 10.1021/acs.jpcb.9b06091] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Hanne Antila
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
| | - Pavel Buslaev
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, 141701 Russia
| | - Fernando Favela-Rosales
- Departamento de Investigación, Tecnológico Nacional de México, Campus Zacatecas Occidente, C. P. 99102 Zacatecas, México
| | - Tiago M. Ferreira
- NMR Group - Institute for Physics, Martin-Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Ivan Gushchin
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, 141701 Russia
| | - Matti Javanainen
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 542/2, CZ-16610 Prague 6, Czech Republic
| | - Batuhan Kav
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
| | - Jesper J. Madsen
- Department of Chemistry, The University of Chicago, 60637 Chicago, Illinois, United States of America
- Department of Global Health, College of Public Health, University of South Florida, 33612 Tampa, Florida, United States of America
| | - Josef Melcr
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 542/2, CZ-16610 Prague 6, Czech Republic
- Groningen Biomolecular Sciences and Biotechnology Institute and The Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Markus S. Miettinen
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
| | - Jukka Määttä
- Department of Chemistry and Materials Science, Aalto University, 00076 Espoo, Finland
| | - Ricky Nencini
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 542/2, CZ-16610 Prague 6, Czech Republic
| | - O. H. Samuli Ollila
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 542/2, CZ-16610 Prague 6, Czech Republic
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Thomas J. Piggot
- Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
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37
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Alginate-coating of artemisinin-loaded cochleates results in better control over gastro-intestinal release for effective oral delivery. J Drug Deliv Sci Technol 2019. [DOI: 10.1016/j.jddst.2019.04.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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38
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Abstract
The condensing effect and the ability of cholesterol (CHOL) to induce ordering in lipid films is a question of relevance in biological membranes such as the milk fat globule membrane (MFGM) in which the amount of CHOL influences the phase separation and mechanical resistance to rupture of coexisting phases relevant to emulsified food systems. Here, we study the effect of different salts (NaCl, CaCl2, MgCl2, LaCl3) on monolayers made of a model mixture of lipids (DPPC:DPPS 4:1) and CHOL. To this end, we apply Langmuir Film Balance to report a combined analysis of surface pressure-area (π-A) and surface potential-area (ΔV–A) isotherms along with Micro-Brewster Angle Microscopy (Micro-BAM) images of the monolayers in the presence of the different electrolytes. We show that the condensation of lipid by CHOL depends strongly on the nature of the ions by altering the shape and features of the π-A isotherms. ΔV–A isotherms provide further detail on the ion specific interactions with CHOL. Our results show that the condensation of lipids in the presence of CHOL depends on the combined action of ions and CHOL, which can alter the physical state of the monolayer.
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39
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Local membrane charge regulates β 2 adrenergic receptor coupling to G i3. Nat Commun 2019; 10:2234. [PMID: 31110175 PMCID: PMC6527575 DOI: 10.1038/s41467-019-10108-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Accepted: 04/18/2019] [Indexed: 11/13/2022] Open
Abstract
The β2 adrenergic receptor (β2AR) signals through both Gs and Gi in cardiac myocytes, and the Gi pathway counteracts the Gs pathway. However, Gi coupling is much less efficient than Gs coupling in most cell-based and biochemical assays, making it difficult to study β2AR−Gi interactions. Here we investigate the role of phospholipid composition on Gs and Gi coupling. While negatively charged phospholipids are known to enhance agonist affinity and stabilize an active state of the β2AR, we find that they impair coupling to Gi3 and facilitate coupling to Gs. Positively charged Ca2+ and Mg2+, known to interact with the negative charge on phospholipids, facilitates Gi3 coupling. Mutational analysis suggests that Ca2+ coordinates an interaction between phospholipid and the negatively charged EDGE motif on the amino terminal helix of Gi3. Taken together, our observations suggest that local membrane charge modulates the interaction between β2AR and competing G protein subtypes. In the healthy heart, the β2 adrenergic receptor (β2AR) signals through Gs and Gi proteins but the mechanism underlying G protein selectivity is not fully understood. Here, the authors show that membrane charge and intracellular cations modulate the β2AR−Gi3 interaction.
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40
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Hoejholt KL, Mužić T, Jensen SD, Dalgaard LT, Bilgin M, Nylandsted J, Heimburg T, Frandsen SK, Gehl J. Calcium electroporation and electrochemotherapy for cancer treatment: Importance of cell membrane composition investigated by lipidomics, calorimetry and in vitro efficacy. Sci Rep 2019; 9:4758. [PMID: 30894594 PMCID: PMC6427041 DOI: 10.1038/s41598-019-41188-z] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 02/20/2019] [Indexed: 12/21/2022] Open
Abstract
Calcium electroporation is a novel anti-cancer treatment investigated in clinical trials. We explored cell sensitivity to calcium electroporation and electroporation with bleomycin, using viability assays at different time and temperature points, as well as heat calorimetry, lipidomics, and flow cytometry. Three cell lines: HT29 (colon cancer), MDA-MB231 (breast cancer), and HDF-n (normal fibroblasts) were investigated for; (a) cell survival dependent on time of addition of drug relative to electroporation (1.2 kV/cm, 8 pulses, 99 µs, 1 Hz), at different temperatures (37 °C, 27 °C, 17 °C); (b) heat capacity profiles obtained by differential scanning calorimetry without added calcium; (c) lipid composition by mass spectrometry; (d) phosphatidylserine in the plasma membrane outer leaflet using flow cytometry. Temperature as well as time of drug administration affected treatment efficacy in HT29 and HDF-n cells, but not MDA-MB231 cells. Interestingly the HT29 cell line displayed a higher phase transition temperature (approximately 20 °C) versus 14 °C (HDF-n) and 15 °C (MDA-MB231). Furthermore the HT29 cell membranes had a higher ratio of ethers to esters, and a higher expression of phosphatidylserine in the outer leaflet. In conclusion, lipid composition and heat capacity of the membrane might influence permeabilisation of cells and thereby the effect of calcium electroporation and electrochemotherapy.
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Affiliation(s)
- K L Hoejholt
- Center for Experimental Drug and Gene Electrotransfer, Department of Oncology, Copenhagen University Hospital Herlev, Herlev, Denmark
| | - T Mužić
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - S D Jensen
- Center for Experimental Drug and Gene Electrotransfer, Department of Oncology, Copenhagen University Hospital Herlev, Herlev, Denmark
| | - L T Dalgaard
- Department of Science and Environment, Roskilde University, Roskilde, Denmark
| | - M Bilgin
- Danish Cancer Society Research Center (DCRC), Copenhagen, Denmark
| | - J Nylandsted
- Danish Cancer Society Research Center (DCRC), Copenhagen, Denmark
| | - T Heimburg
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - S K Frandsen
- Center for Experimental Drug and Gene Electrotransfer, Department of Oncology, Copenhagen University Hospital Herlev, Herlev, Denmark.
- Center for Experimental Drug and Gene Electrotransfer, Department of Clinical Oncology and Palliative Care, Zealand University Hospital, Roskilde, Denmark.
| | - J Gehl
- Center for Experimental Drug and Gene Electrotransfer, Department of Oncology, Copenhagen University Hospital Herlev, Herlev, Denmark.
- Center for Experimental Drug and Gene Electrotransfer, Department of Clinical Oncology and Palliative Care, Zealand University Hospital, Roskilde, Denmark.
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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41
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Hallock MJ, Greenwood AI, Wang Y, Morrissey JH, Tajkhorshid E, Rienstra CM, Pogorelov TV. Calcium-Induced Lipid Nanocluster Structures: Sculpturing of the Plasma Membrane. Biochemistry 2018; 57:6897-6905. [PMID: 30456950 DOI: 10.1021/acs.biochem.8b01069] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The plasma membrane of the cell is a complex, tightly regulated, heterogeneous environment shaped by proteins, lipids, and small molecules. Ca2+ ions are important cellular messengers, spatially separated from anionic lipids. After cell injury, disease, or apoptotic events, anionic lipids are externalized to the outer leaflet of the plasma membrane and encounter Ca2+, resulting in dramatic changes in the plasma membrane structure and initiation of signaling cascades. Despite the high chemical and biological significance, the structures of lipid-Ca2+ nanoclusters are still not known. Previously, we demonstrated by solid-state nuclear magnetic resonance (NMR) spectroscopy that upon binding to Ca2+, individual phosphatidylserine lipids populate two distinct yet-to-be-characterized structural environments. Here, we concurrently employ extensive all-atom molecular dynamics (MD) simulations with our accelerated membrane mimetic and detailed NMR measurements to identify lipid-Ca2+ nanocluster conformations. We find that major structural characteristics of these nanoclusters, including interlipid pair distances and chemical shifts, agree with observable NMR parameters. Simulations reveal that lipid-ion nanoclusters are shaped by two characteristic, long-lived lipid structures induced by divalent Ca2+. Using ab initio quantum mechanical calculations of chemical shifts on MD-captured lipid-ion complexes, we show that computationally observed conformations are validated by experimental NMR data. Both NMR measurements of diluted specifically labeled lipids and MD simulations reveal that the basic structural unit that reshapes the membrane is a Ca2+-coordinated phosphatidylserine tetramer. Our combined computational and experimental approach presented here can be applied to other complex systems in which charged membrane-active molecular agents leave structural signatures on lipids.
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Affiliation(s)
- Michael J Hallock
- School of Chemical Sciences , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Alexander I Greenwood
- Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Yan Wang
- Department of Biochemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - James H Morrissey
- Department of Biological Chemistry , University of Michigan Medical School , Ann Arbor , Michigan 48103 , United States
| | - Emad Tajkhorshid
- Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Department of Biochemistry , 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.,Center for Biophysics and Quantitative Biology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Chad M Rienstra
- Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Department of Biochemistry , 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.,Center for Biophysics and Quantitative Biology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Taras V Pogorelov
- School of Chemical Sciences , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Department of Biochemistry , 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.,Center for Biophysics and Quantitative 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
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42
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Forchielli ML, Bonoli A, Stancari A, Bruno LL, Piro F, Piazza G, Albertini C, Pession A, Puggioli C, Bersani G. Do carnitine and extra trace elements change stability of paediatric parenteral nutrition admixtures? Clin Nutr 2018; 38:2369-2374. [PMID: 30442387 DOI: 10.1016/j.clnu.2018.10.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 10/12/2018] [Accepted: 10/20/2018] [Indexed: 10/28/2022]
Abstract
INTRODUCTION High concentrations of trace elements (TE), in particular zinc and selenium, along with carnitine, are often added to parenteral admixtures in paediatric patients on long-term Parenteral Nutrition (PN). We aim to evaluate whether lipid droplet diameters of these admixtures maintain the recommended range of 0.4-1.0 μm. MATERIALS AND METHODS Stability studies were carried out on six parenteral admixtures with carnitine, trace elements and electrolytes added in different amounts. Each admixture was formulated with five different lipid emulsions with or without fish oil. Analyses were performed at time 0 (t = 0) and 24, 48, 72, 96 (t = 96) hours after compounding. Droplet diameters were determined by Light Scattering-Reverse Fourier Optics Technique. Samples, stored at 4 °C, were triple tested for a total of 450 analyses. Regression analyses were performed using panel-data techniques. RESULTS During the 4 days, lipid droplet diameters were in the expected range of 0.4-1.0 μm regardless of trace element and carnitine amounts in all admixtures apart from those containing fish-oil based emulsions and calcium concentrations equal to 4.5 mmol/L. In these latter admixtures, 12% of droplet diameters were larger than 1.0 μm and 2% exceeded 5.0 μm immediately after compounding. CONCLUSION Carnitine and high concentrations of trace elements do not affect PN admixtures stability and can be safely infused in long-term home-PN paediatric patients and prematures. Only high calcium concentrations in compresence with fish oil based lipid emulsions seem to change PN stability.
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Affiliation(s)
- M L Forchielli
- Paediatrics, S.Orsola-Malpighi Medical School, Bologna, Italy.
| | - A Bonoli
- Civil, Environmental and Materials Engineering Department, University of Bologna, Italy
| | - A Stancari
- Pharmacy Service, S. Orsola-Malpighi Medical School, Bologna, Italy
| | - L L Bruno
- Pharmacy Service, S. Orsola-Malpighi Medical School, Bologna, Italy
| | - F Piro
- Pharmacy Service, S. Orsola-Malpighi Medical School, Bologna, Italy
| | - G Piazza
- Pharmacy Service, S. Orsola-Malpighi Medical School, Bologna, Italy
| | - C Albertini
- Paediatrics, S.Orsola-Malpighi Medical School, Bologna, Italy
| | - A Pession
- Paediatrics, S.Orsola-Malpighi Medical School, Bologna, Italy
| | - C Puggioli
- Pharmacy Service, S. Orsola-Malpighi Medical School, Bologna, Italy
| | - G Bersani
- Consulting Pharmacist, Bologna, Italy
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43
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Cebecauer M, Amaro M, Jurkiewicz P, Sarmento MJ, Šachl R, Cwiklik L, Hof M. Membrane Lipid Nanodomains. Chem Rev 2018; 118:11259-11297. [PMID: 30362705 DOI: 10.1021/acs.chemrev.8b00322] [Citation(s) in RCA: 128] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Lipid membranes can spontaneously organize their components into domains of different sizes and properties. The organization of membrane lipids into nanodomains might potentially play a role in vital functions of cells and organisms. Model membranes represent attractive systems to study lipid nanodomains, which cannot be directly addressed in living cells with the currently available methods. This review summarizes the knowledge on lipid nanodomains in model membranes and exposes how their specific character contrasts with large-scale phase separation. The overview on lipid nanodomains in membranes composed of diverse lipids (e.g., zwitterionic and anionic glycerophospholipids, ceramides, glycosphingolipids) and cholesterol aims to evidence the impact of chemical, electrostatic, and geometric properties of lipids on nanodomain formation. Furthermore, the effects of curvature, asymmetry, and ions on membrane nanodomains are shown to be highly relevant aspects that may also modulate lipid nanodomains in cellular membranes. Potential mechanisms responsible for the formation and dynamics of nanodomains are discussed with support from available theories and computational studies. A brief description of current fluorescence techniques and analytical tools that enabled progress in lipid nanodomain studies is also included. Further directions are proposed to successfully extend this research to cells.
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Affiliation(s)
- Marek Cebecauer
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Mariana Amaro
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Piotr Jurkiewicz
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Maria João Sarmento
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Radek Šachl
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Lukasz Cwiklik
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Martin Hof
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
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44
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Valentine ML, Cardenas AE, Elber R, Baiz CR. Physiological Calcium Concentrations Slow Dynamics at the Lipid-Water Interface. Biophys J 2018; 115:1541-1551. [PMID: 30269885 PMCID: PMC6260210 DOI: 10.1016/j.bpj.2018.08.044] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 08/20/2018] [Accepted: 08/27/2018] [Indexed: 02/07/2023] Open
Abstract
Phospholipids can interact strongly with ions at physiological concentrations, and these interactions can alter membrane properties. Here, we describe the effects of calcium ions on the dynamics in phospholipid membranes. We used a combination of time-resolved ultrafast two-dimensional infrared spectroscopy and molecular dynamics simulations. We found that millimolar Ca2+ concentrations lead to slower fluctuations in the local environment at the lipid-water interface of membranes with phosphatidylserine. The effect was only observed in bilayers containing anionic phosphatidylserine; membranes composed of only zwitterionic phosphatidylcholine did not experience a slowdown. Local water dynamics were measured using the ester groups as label-free probes and were found to be up to 50% slower with 2.5 mM Ca2+. Molecular dynamics simulations show that Ca2+ primarily binds to the carboxylate group of phosphatidylserines. These findings have implications for apoptotic and diseased cells in which phosphatidylserine is exposed to extracellular calcium and for the biophysical effects of divalent cations on lipid bilayers.
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Affiliation(s)
- Mason L Valentine
- Department of Chemistry, University of Texas at Austin, Austin, Texas
| | - Alfredo E Cardenas
- Department of Chemistry, University of Texas at Austin, Austin, Texas; Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, Texas
| | - Ron Elber
- Department of Chemistry, University of Texas at Austin, Austin, Texas; Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, Texas
| | - Carlos R Baiz
- Department of Chemistry, University of Texas at Austin, Austin, Texas.
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45
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Ali Doosti B, Cans AS, Jeffries GDM, Lobovkina T. Membrane Remodeling of Giant Vesicles in Response to Localized Calcium Ion Gradients. J Vis Exp 2018. [PMID: 30059020 PMCID: PMC6126466 DOI: 10.3791/57789] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
In a wide variety of fundamental cell processes, such as membrane trafficking and apoptosis, cell membrane shape transitions occur concurrently with local variations in calcium ion concentration. The main molecular components involved in these processes have been identified; however, the specific interplay between calcium ion gradients and the lipids within the cell membrane is far less known, mainly due to the complex nature of biological cells and the difficultly of observation schemes. To bridge this gap, a synthetic approach is successfully implemented to reveal the localized effect of calcium ions on cell membrane mimics. Establishing a mimic to resemble the conditions within a cell is a severalfold problem. First, an adequate biomimetic model with appropriate dimensions and membrane composition is required to capture the physical properties of cells. Second, a micromanipulation setup is needed to deliver a small amount of calcium ions to a particular membrane location. Finally, an observation scheme is required to detect and record the response of the lipid membrane to the external stimulation. This article offers a detailed biomimetic approach for studying the calcium ion-membrane interaction, where a lipid vesicle system, consisting of a giant unilamellar vesicle (GUV) connected to a multilamellar vesicle (MLV), is exposed to a localized calcium gradient formed using a microinjection system. The dynamics of the ionic influence on the membrane were observed using fluorescence microscopy and recorded at video frame rates. As a result of the membrane stimulation, highly curved membrane tubular protrusions (MTPs) formed inside the GUV, oriented away from the membrane. The described approach induces the remodeling of the lipid membrane and MTP production in an entirely contactless and controlled manner. This approach introduces a means to address the details of calcium ion-membrane interactions, providing new avenues to study the mechanisms of cell membrane reshaping.
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Affiliation(s)
- Baharan Ali Doosti
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology
| | - Ann-Sofie Cans
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology
| | - Gavin D M Jeffries
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology
| | - Tatsiana Lobovkina
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology;
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46
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Liu Y, Liu J. Cu 2+-Directed Liposome Membrane Fusion, Positive-Stain Electron Microscopy, and Oxidation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:7545-7553. [PMID: 29804456 DOI: 10.1021/acs.langmuir.8b00864] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Natural lipid headgroups contain a few types of metal ligands, such as phosphate, amine, and serine, which interact with metal ions differently. Herein, we studied the binding between Cu2+ and liposomes with four types of headgroups: phosphocholine (PC), phosphoglycerol (PG), phosphoserine (PS), and cholinephosphate (CP). Using fluorescently headgroup-labeled liposomes, Cu2+ strongly quenched the CP and PS liposomes, whereas quenching of PC and PG was weaker. Dynamic light scattering indicated that all of the four liposomes aggregated at high Cu2+ concentrations, and ethylenediaminetetraacetic acid (EDTA) only restored the original size of the PC liposome, implying fusion of the other three types of liposomes. The leakage tests revealed that the integrity of PC liposomes was not affected by Cu2+, but the other three liposomes leaked. Under TEM, all of the liposomes show a positive-stain feature in the presence of Cu2+ and Cu2+-stained individual liposomes with a short incubation time (<1 min). The oxidative catalytic property of Cu2+ was also tested, and a tight binding by the PS liposome inhibited the activity of Cu2+. Finally, a model of interaction for each liposome was proposed, and each one has a different metal-binding and interaction mechanism.
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Affiliation(s)
- Yibo Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology , University of Waterloo , Waterloo , Ontario N2L 3G1 , Canada
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology , University of Waterloo , Waterloo , Ontario N2L 3G1 , Canada
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47
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Tsutsui Y, Hays FA. A Link Between Alzheimer's and Type II Diabetes Mellitus? Ca +2 -Mediated Signal Control and Protein Localization. Bioessays 2018; 40:e1700219. [PMID: 29694668 PMCID: PMC6166406 DOI: 10.1002/bies.201700219] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 03/16/2018] [Indexed: 01/28/2023]
Abstract
We propose protein localization dependent signal activation (PLDSA) as a model to describe pre-existing protein partitioning between the cytosol, and membrane surface, as a means to modulate signal activation, specificity, and robustness. We apply PLDSA to explain possible molecular links between type II diabetes mellitus (T2DM) and Alzheimer's disease (AD) by describing Ca+2 -mediated interactions between the Src non-receptor tyrosine kinase and p52Shc adaptor protein. We suggest that these interactions may serve as a contributing factor to disease development and progression. In particular, we propose that signaling response is regulated, in part, by Ca+2 -mediated partitioning of lipid-bound and soluble forms of Src and p52shc. Thus, protein-protein interactions that drive signaling in response to extracellular ligand binding are also mediated by partitioning of signaling proteins between membrane-bound and soluble populations. We propose that PLDSA effects may explain, in part, the evolutionary basis of promiscuous protein interaction domains and their importance in cellular function.
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Affiliation(s)
- Yuko Tsutsui
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, United States
| | - Franklin A. Hays
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, United States
- Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, United States
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, United States
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48
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Kirejev V, Ali Doosti B, Shaali M, Jeffries GDM, Lobovkina T. Contactless Stimulation and Control of Biomimetic Nanotubes by Calcium Ion Gradients. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1703541. [PMID: 29665219 DOI: 10.1002/smll.201703541] [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: 10/10/2017] [Revised: 03/12/2018] [Indexed: 06/08/2023]
Abstract
Membrane tubular structures are important communication pathways between cells and cellular compartments. Studying these structures in their native environment is challenging, due to the complexity of membranes and varying chemical conditions within and outside of the cells. This work demonstrates that a calcium ion gradient, applied to a synthetic lipid nanotube, triggers lipid flow directed toward the application site, resulting in the formation of a bulge aggregate. This bulge can be translated in a contactless manner by moving a calcium ion source along the lipid nanotube. Furthermore, entrapment of polystyrene nanobeads within the bulge does not tamper the bulge movement and allows transporting of the nanoparticle cargo along the lipid nanotube. In addition to the synthetic lipid nanotubes, the response of cell plasma membrane tethers to local calcium ion stimulation is investigated. The directed membrane transport in these tethers is observed, but with slower kinetics in comparison to the synthetic lipid nanotubes. The findings of this work demonstrate a novel and contactless mode of transport in lipid nanotubes, guided by local exposure to calcium ions. The observed lipid nanotube behavior can advance the current understanding of the cell membrane tubular structures, which are constantly reshaped during dynamic cellular processes.
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Affiliation(s)
- Vladimir Kirejev
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 9, SE-412 96, Göteborg, Sweden
| | - Baharan Ali Doosti
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 9, SE-412 96, Göteborg, Sweden
| | - Mehrnaz Shaali
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 9, SE-412 96, Göteborg, Sweden
| | - Gavin D M Jeffries
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 9, SE-412 96, Göteborg, Sweden
| | - Tatsiana Lobovkina
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 9, SE-412 96, Göteborg, Sweden
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49
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Laudadio E, Minnelli C, Amici A, Massaccesi L, Mobbili G, Galeazzi R. Liposomal Formulations for an Efficient Encapsulation of Epigallocatechin-3-gallate: An in- Silico/Experimental Approach. Molecules 2018; 23:molecules23020441. [PMID: 29462955 PMCID: PMC6017453 DOI: 10.3390/molecules23020441] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 02/07/2018] [Accepted: 02/13/2018] [Indexed: 01/29/2023] Open
Abstract
As a part of research project aimed to optimize antioxidant delivery, here we studied the influence of both salts and lipid matrix composition on the interaction of epigallocatechin-3-gallate (EGCG) with bilayer leaflets. Thus, we combined in silico and experimental methods to study the ability of neutral and anionic vesicles to encapsulate EGCG in the presence of Ca2+ and Mg2+ divalent salts. Experimental and in silico results show a very high correlation, thus confirming the efficiency of the developed methodology. In particular, we found out that the presence of calcium ions hinders the insertion of EGCG in the liposome bilayer in both neutral and anionic systems. On the contrary, the presence of MgCl2 improves the insertion degree of EGCG molecules respect to the liposomes without divalent salts. The best and most efficient salt concentration is that corresponding to a 5:1 molar ratio between Mg2+ and EGCG, in both neutral and anionic vesicles. Concerning the lipid matrix composition, the anionic one results in better promotion of the catechin insertion within the bilayer since experimentally we achieved 100% EGCG encapsulation in the lipid carrier in the presence of a 5:1 molar ratio of magnesium. Thus, the combination of this anionic liposomal formulation with magnesium chloride, avoids time-consuming separation steps of unentrapped active principle and appears particularly suitable for EGCG delivery applications.
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Affiliation(s)
- Emiliano Laudadio
- Dipartimento di Scienze della Vita e dell'Ambiente (DISVA), Università Politecnica delle Marche, via Brecce Bianche, 60131 Ancona, Italy.
| | - Cristina Minnelli
- Dipartimento di Scienze della Vita e dell'Ambiente (DISVA), Università Politecnica delle Marche, via Brecce Bianche, 60131 Ancona, Italy.
| | - Adolfo Amici
- Dipartimento Scienze Cliniche Specialistiche ed Odontostomatologiche, Università Politecnica delle Marche, via Brecce Bianche, 60131 Ancona, Italy.
| | - Luca Massaccesi
- Dipartimento di Scienze della Vita e dell'Ambiente (DISVA), Università Politecnica delle Marche, via Brecce Bianche, 60131 Ancona, Italy.
| | - Giovanna Mobbili
- Dipartimento di Scienze della Vita e dell'Ambiente (DISVA), Università Politecnica delle Marche, via Brecce Bianche, 60131 Ancona, Italy.
| | - Roberta Galeazzi
- Dipartimento di Scienze della Vita e dell'Ambiente (DISVA), Università Politecnica delle Marche, via Brecce Bianche, 60131 Ancona, Italy.
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50
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Ali Doosti B, Pezeshkian W, Bruhn DS, Ipsen JH, Khandelia H, Jeffries GDM, Lobovkina T. Membrane Tubulation in Lipid Vesicles Triggered by the Local Application of Calcium Ions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:11010-11017. [PMID: 28910109 DOI: 10.1021/acs.langmuir.7b01461] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Experimental and theoretical studies on ion-lipid interactions predict that binding of calcium ions to cell membranes leads to macroscopic mechanical effects and membrane remodeling. Herein, we provide experimental evidence that a point source of Ca2+ acting upon a negatively charged membrane generates spontaneous curvature and triggers the formation of tubular protrusions that point away from the ion source. This behavior is rationalized by strong binding of the divalent cations to the surface of the charged bilayer, which effectively neutralizes the surface charge density of outer leaflet of the bilayer. The mismatch in the surface charge density of the two leaflets leads to nonzero spontaneous curvature. We probe this mismatch through the use of molecular dynamics simulations and validate that calcium ion binding to a lipid membrane is sufficient to generate inward spontaneous curvature, bending the membrane. Additionally, we demonstrate that the formed tubular protrusions can be translated along the vesicle surface in a controlled manner by repositioning the site of localized Ca2+ exposure. The findings demonstrate lipid membrane remodeling in response to local chemical gradients and offer potential insights into the cell membrane behavior under conditions of varying calcium ion concentrations.
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Affiliation(s)
- Baharan Ali Doosti
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-412 96 Gothenburg, Sweden
| | - Weria Pezeshkian
- Center for Biomembrane Physics (MEMPHYS), Department of Physics, Chemistry and Pharmacy (FKF), University of Southern Denmark , Campusvej 55, 5230 Odense M, Denmark
| | - Dennis S Bruhn
- Center for Biomembrane Physics (MEMPHYS), Department of Physics, Chemistry and Pharmacy (FKF), University of Southern Denmark , Campusvej 55, 5230 Odense M, Denmark
| | - John H Ipsen
- Center for Biomembrane Physics (MEMPHYS), Department of Physics, Chemistry and Pharmacy (FKF), University of Southern Denmark , Campusvej 55, 5230 Odense M, Denmark
| | - Himanshu Khandelia
- Center for Biomembrane Physics (MEMPHYS), Department of Physics, Chemistry and Pharmacy (FKF), University of Southern Denmark , Campusvej 55, 5230 Odense M, Denmark
| | - Gavin D M Jeffries
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-412 96 Gothenburg, Sweden
| | - Tatsiana Lobovkina
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-412 96 Gothenburg, Sweden
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