201
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Abstract
Here we report methods of preparation for liposome formulations containing lipophilic drugs. In contrast to the encapsulation of water soluble compounds into the entrapped aqueous volume of a liposome, drugs with lipophilic properties are incorporated into the phospholipid bilayer membrane. Water-soluble molecules, for example cytotoxic or antiviral nucleosides can be transformed into lipophilic compounds by attachment of long alkyl chains, allowing their stable incorporation into liposome membranes and taking advantage of the high loading capacity lipid bilayers provide for lipophilic molecules. We created a new class of cytotoxic drugs by chemical transformation of the hydrophilic drugs cytosine-arabinoside (ara-C), 5-fluoro-deoxyuridine (5-FdU), and ethinylcytidine (ETC) into lipophilic compounds and their formulation in liposomes.The concept of chemical modification of water-soluble molecules by attachment of long alkyl chains and their stable incorporation into liposome bilayer membranes represent a very promising method for the development of new drugs not only for the treatment of tumors or infections but also for many other diseases.
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Affiliation(s)
- Reto A Schwendener
- Laboratory of Liposome Research, Institute of Molecular Cancer Research, University of Zürich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
| | - Herbert Schott
- Institute of Organic Chemistry, Eberhard-Karls University, Auf der Morgenstelle 18, 72076, Tübingen, Germany
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202
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Arias M, Vogel HJ. Fluorescence and Absorbance Spectroscopy Methods to Study Membrane Perturbations by Antimicrobial Host Defense Peptides. Methods Mol Biol 2017; 1548:141-157. [PMID: 28013502 DOI: 10.1007/978-1-4939-6737-7_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Antimicrobial peptides (AMPs) are currently intensely studied because of their potential as new bactericidal and bacteriostatic agents. The mechanism of action of numerous AMPs involves the permeabilization of bacterial membranes. Several methods have been developed to study peptide-membrane interactions; in particular optical spectroscopy methods are widely used. The intrinsic fluorescence properties of the Trp indole ring in Trp-containing AMPs can be exploited by measuring the fluorescence blue shift and acrylamide-induced fluorescence quenching. One important aspect of such studies is the use of distinct models of the bacterial membrane, in most cases large unilamellar vesicles (LUVs) with different, yet well-defined, phospholipid compositions. Deploying LUVs that are preloaded with fluorescent dyes, such as calcein, also allows for the study of vesicle permeabilization by AMPs. In addition, experiments using genetically engineered live Escherichia coli cells can be used to distinguish between the effects of AMPs on the outer and inner membranes of gram-negative bacteria. In combination, these methods can provide a detailed insight into the mode of action of AMPs.
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Affiliation(s)
- Mauricio Arias
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB, Canada, T2N 1N4
| | - Hans J Vogel
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB, Canada, T2N 1N4.
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203
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Espinosa-Bustos C, Cortés-Arriagada D, Soto-Arriaza MA, Robinson-Duggon J, Pizarro N, Cabrera AR, Fuentealba D, Salas CO. Fluorescence properties of aurone derivatives: an experimental and theoretical study with some preliminary biological applications. Photochem Photobiol Sci 2017. [DOI: 10.1039/c7pp00078b] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper, we explored the fluorescence properties of eight aurone derivatives bearing methoxy groups and bromine atoms as substituents in the benzene rings.
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Affiliation(s)
- Christian Espinosa-Bustos
- Departamento de Química Orgánica
- Facultad de Química
- Pontificia Universidad Católica de Chile
- Santiago 6094411
- Chile
| | - Diego Cortés-Arriagada
- Programa Institucional de Fomento a la Investigación
- Desarrollo e Innovación. Universidad Tecnológica Metropolitana
- Santiago
- Chile
| | - Marco A. Soto-Arriaza
- Departamento de Química Física
- Facultad de Química
- Pontificia Universidad Católica de Chile
- Santiago 6094411
- Chile
| | - José Robinson-Duggon
- Departamento de Química Física
- Facultad de Química
- Pontificia Universidad Católica de Chile
- Santiago 6094411
- Chile
| | - Nancy Pizarro
- Departamento de Ciencias Químicas
- Facultad de Ciencias Exactas
- Universidad Andrés Bello
- Viña del Mar 2531015
- Chile
| | - Alan R. Cabrera
- Departamento de Química Orgánica
- Facultad de Química
- Pontificia Universidad Católica de Chile
- Santiago 6094411
- Chile
| | - Denis Fuentealba
- Departamento de Química Física
- Facultad de Química
- Pontificia Universidad Católica de Chile
- Santiago 6094411
- Chile
| | - Cristian O. Salas
- Departamento de Química Orgánica
- Facultad de Química
- Pontificia Universidad Católica de Chile
- Santiago 6094411
- Chile
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204
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Ong SGM, Chitneni M, Lee KS, Ming LC, Yuen KH. Evaluation of Extrusion Technique for Nanosizing Liposomes. Pharmaceutics 2016; 8:E36. [PMID: 28009829 PMCID: PMC5198018 DOI: 10.3390/pharmaceutics8040036] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Revised: 11/10/2016] [Accepted: 12/06/2016] [Indexed: 11/17/2022] Open
Abstract
The aim of the present study was to study the efficiency of different techniques used for nanosizing liposomes. Further, the aim was also to evaluate the effect of process parameters of extrusion techniques used for nanosizing liposomes on the size and size distribution of the resultant liposomes. To compare the efficiency of different nanosizing techniques, the following techniques were used to nanosize the liposomes: extrusion, ultrasonication, freeze-thaw sonication (FTS), sonication and homogenization. The extrusion technique was found to be the most efficient, followed by FTS, ultrasonication, sonication and homogenization. The extruder used in the present study was fabricated using readily available and relatively inexpensive apparatus. Process parameters were varied in extrusion technique to study their effect on the size and size distribution of extruded liposomes. The results obtained indicated that increase in the flow rate of the extrusion process decreased the size of extruded liposomes however the size homogeneity was negatively impacted. Furthermore, the liposome size and distribution was found to decline with decreasing membrane pore size. It was found that by extruding through a filter with a pore size of 0.2 µm and above, the liposomes produced were smaller than the pore size, whereas, when they were extruded through a filter with a pore size of less than 0.2 µm the resultant liposomes were slightly bigger than the nominal pore size. Besides that, increment of extrusion temperature above transition temperature of the pro-liposome had no effect on the size and size distribution of the extruded liposomes. In conclusion, the extrusion technique was reproducible and effective among all the methods evaluated. Furthermore, processing parameters used in extrusion technique would affect the size and size distribution of liposomes. Therefore, the process parameters need to be optimized to obtain a desirable size range and homogeneity, reproducible for various in vivo applications.
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Affiliation(s)
- Sandy Gim Ming Ong
- School of Pharmaceutical Sciences, University of Science Malaysia, 11800 Penang, Malaysia.
| | | | - Kah Seng Lee
- Pharmacy, School of Medicine, University of Tasmania, Hobart 7001, Tasmania, Australia.
| | - Long Chiau Ming
- Pharmacy, School of Medicine, University of Tasmania, Hobart 7001, Tasmania, Australia.
| | - Kah Hay Yuen
- School of Pharmaceutical Sciences, University of Science Malaysia, 11800 Penang, Malaysia.
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205
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Ikeda K, Nakano M. Energetics of the Mixing of Phospholipids in Bilayers Determined Using Vesicle Solubilization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:13270-13275. [PMID: 27951688 DOI: 10.1021/acs.langmuir.6b03333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Here, we report an experimental approach for determining the change in the free energy and the enthalpy that accompanies the mixing of the anionic phosphatidylglycerol and the zwitterionic phosphatidylcholine. The enthalpy change originates in the thermal changes of disrupting lipid bilayer vesicles titrated into a surfactant micelle solution and is monitored using isothermal titration calorimetry. The difference in the solubilization enthalpies between pure and mixed lipid vesicles yields the lipid mixing enthalpy. The Gibbs free energy changes are estimated by determining the thermodynamic equilibrium constants of forming a molecular complex between phospholipids and methyl-β-cyclodextrin. We provide direct experimental evidence that mixing of the anionic lipid and the zwitterionic lipid is explained well by the entropic term of the electrostatic free energy of a charged surface in the Gouy-Chapman model. The present strategy enables us to determine the precise energetics of lipid-lipid interactions in near-native environments such as liposomes without any chemical modification to lipid molecules.
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Affiliation(s)
- Keisuke Ikeda
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama , Toyama 930-0194, Japan
| | - Minoru Nakano
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama , Toyama 930-0194, Japan
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206
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Kusler K, Odoh SO, Silakov A, Poyton MF, Pullanchery S, Cremer PS, Gagliardi L. What Is the Preferred Conformation of Phosphatidylserine–Copper(II) Complexes? A Combined Theoretical and Experimental Investigation. J Phys Chem B 2016; 120:12883-12889. [DOI: 10.1021/acs.jpcb.6b10675] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kari Kusler
- Department
of Chemistry, Chemical Theory Center, and Minnesota Supercomputing
Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
| | - Samuel O. Odoh
- Department
of Chemistry, Chemical Theory Center, and Minnesota Supercomputing
Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
| | - Alexey Silakov
- Department
of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Matthew F. Poyton
- Department
of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Saranya Pullanchery
- Department
of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Paul S. Cremer
- Department
of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Laura Gagliardi
- Department
of Chemistry, Chemical Theory Center, and Minnesota Supercomputing
Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
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207
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Francois-Moutal L, Ouberai MM, Maniti O, Welland ME, Strzelecka-Kiliszek A, Wos M, Pikula S, Bandorowicz-Pikula J, Marcillat O, Granjon T. Two-Step Membrane Binding of NDPK-B Induces Membrane Fluidity Decrease and Changes in Lipid Lateral Organization and Protein Cluster Formation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:12923-12933. [PMID: 27934520 DOI: 10.1021/acs.langmuir.6b03789] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Nucleoside diphosphate kinases (NDPKs) are crucial elements in a wide array of cellular physiological or pathophysiological processes such as apoptosis, proliferation, or metastasis formation. Among the NDPK isoenzymes, NDPK-B, a cytoplasmic protein, was reported to be associated with several biological membranes such as plasma or endoplasmic reticulum membranes. Using several membrane models (liposomes, lipid monolayers, and supported lipid bilayers) associated with biophysical approaches, we show that lipid membrane binding occurs in a two-step process: first, initiation by a strong electrostatic adsorption process and followed by shallow penetration of the protein within the membrane. The NDPK-B binding leads to a decrease in membrane fluidity and formation of protein patches. The ability of NDPK-B to form microdomains at the membrane level may be related to protein-protein interactions triggered by its association with anionic phospholipids. Such accumulation of NDPK-B would amplify its effects in functional platform formation and protein recruitment at the membrane.
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Affiliation(s)
- Liberty Francois-Moutal
- Organisation et Dynamique des Membrane Biologiques, Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, CNRS UMR 5246 ICBMS , Bâtiment Chevreul, 43 Boulevard du 11 Novembre 1918, Villeurbanne Cedex 69622, France
| | - Myriam M Ouberai
- Nanoscience Centre, University of Cambridge , 11 J.J. Thomson Avenue Cambridge, Cambridge CB3 0FF, U.K
| | - Ofelia Maniti
- Organisation et Dynamique des Membrane Biologiques, Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, CNRS UMR 5246 ICBMS , Bâtiment Chevreul, 43 Boulevard du 11 Novembre 1918, Villeurbanne Cedex 69622, France
| | - Mark E Welland
- Nanoscience Centre, University of Cambridge , 11 J.J. Thomson Avenue Cambridge, Cambridge CB3 0FF, U.K
| | - Agnieszka Strzelecka-Kiliszek
- Department of Biochemistry, Nencki Institute of Experimental Biology, Polish Academy of Sciences , 3 Pasteur Street, Warsaw 02-093, Poland
| | - Marcin Wos
- Department of Biochemistry, Nencki Institute of Experimental Biology, Polish Academy of Sciences , 3 Pasteur Street, Warsaw 02-093, Poland
| | - Slawomir Pikula
- Department of Biochemistry, Nencki Institute of Experimental Biology, Polish Academy of Sciences , 3 Pasteur Street, Warsaw 02-093, Poland
| | - Joanna Bandorowicz-Pikula
- Department of Biochemistry, Nencki Institute of Experimental Biology, Polish Academy of Sciences , 3 Pasteur Street, Warsaw 02-093, Poland
| | - Olivier Marcillat
- Organisation et Dynamique des Membrane Biologiques, Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, CNRS UMR 5246 ICBMS , Bâtiment Chevreul, 43 Boulevard du 11 Novembre 1918, Villeurbanne Cedex 69622, France
| | - Thierry Granjon
- Organisation et Dynamique des Membrane Biologiques, Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, CNRS UMR 5246 ICBMS , Bâtiment Chevreul, 43 Boulevard du 11 Novembre 1918, Villeurbanne Cedex 69622, France
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208
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In vitro activation of coagulation by human neutrophil DNA and histone proteins but not neutrophil extracellular traps. Blood 2016; 129:1021-1029. [PMID: 27919911 DOI: 10.1182/blood-2016-06-722298] [Citation(s) in RCA: 150] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 11/29/2016] [Indexed: 12/17/2022] Open
Abstract
NETosis is a physiologic process in which neutrophils release their nuclear material in the form of neutrophil extracellular traps (NETs). NETs have been reported to directly promote thrombosis in animal models. Although the effects of purified NET components including DNA, histone proteins, and neutrophil enzymes on coagulation have been characterized, the mechanism by which intact NETs promote thrombosis is largely unknown. In this study, human neutrophils were stimulated to produce NETs in platelet-free plasma (PFP) or in buffer using phorbol myristate actetate or calcium ionophore. DNA and histone proteins were also separately purified from normal human neutrophils and used to reconstitute chromatin using a salt-gradient dialysis method. Neutrophil stimulation resulted in robust NET release. In recalcified PFP, purified DNA triggered contact-dependent thrombin generation (TG) and amplified TG initiated by low concentrations of tissue factor. Similarly, in a buffer milieu, DNA initiated the contact pathway and amplified thrombin-dependent factor XI activation. Recombinant human histones H3 and H4 triggered TG in recalcified human plasma in a platelet-dependent manner. In contrast, neither intact NETs, reconstituted chromatin, individual nucleosome particles, nor octameric core histones reproduced any of these procoagulant effects. We conclude that unlike DNA or individual histone proteins, human intact NETs do not directly initiate or amplify coagulation in vitro. This difference is likely explained by the complex histone-histone and histone-DNA interactions within the nucleosome unit and higher-order supercoiled chromatin leading to neutralization of the negative charges on polyanionic DNA and modification of the binding properties of individual histone proteins.
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209
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Interaction between amphipathic triblock copolymers and L-α-dipalmitoyl phosphatidylcholine large unilamellar vesicles. Colloids Surf B Biointerfaces 2016; 148:30-40. [DOI: 10.1016/j.colsurfb.2016.08.038] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 08/19/2016] [Accepted: 08/22/2016] [Indexed: 11/24/2022]
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210
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Szpryngiel S, Mäler L. Insights into the Membrane Interacting Properties of the C-Terminal Domain of the Monotopic Glycosyltransferase DGD2 in Arabidopsis thaliana. Biochemistry 2016; 55:6776-6786. [PMID: 27951648 DOI: 10.1021/acs.biochem.6b00559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Glycosyltransferases (GTs) are responsible for regulating the membrane composition of plants. The synthesis of one of the main lipids in the membrane, the galactolipid digalactosyldiacylglycerol, is regulated by the enzyme digalactosyldiacylglycerol synthase 2 (atDGD2) under starving conditions, such as phosphate shortage. The enzyme belongs to the GT-B fold, characterized by two β/α/β Rossmann domains that are connected by a flexible linker. atDGD2 has previously been shown to attach to lipid membranes by the N-terminal domain via interactions with negatively charged lipids. The role of the C-terminal domain in the membrane interaction is, however, not known. Here we have used a combination of in silico prediction methods and biophysical experimental techniques to shed light on the membrane interacting properties of the C-terminal domain. Our results demonstrate that there is an amphipathic sequence, corresponding to residues V240-E258, that interacts with lipids in a charge-dependent way. A second sequence was identified as being potentially important, with a high charge density, but no amphipathic character. The features of the plant atDGD2 observed here are similar in prokaryotic glycosyltransferases. On the basis of our results, and by analogy to other glycosyltransferases, we propose that atDGD2 interacts with the membrane through the N-terminus and with parts of the C-terminus acting as a switch, allowing for a dynamic interaction with the membrane.
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Affiliation(s)
- Scarlett Szpryngiel
- Department of Biochemistry and Biophysics, Center for Biomembrane Research, The Arrhenius Laboratory, Stockholm University , 10691 Stockholm, Sweden
| | - Lena Mäler
- Department of Biochemistry and Biophysics, Center for Biomembrane Research, The Arrhenius Laboratory, Stockholm University , 10691 Stockholm, Sweden
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211
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Philippe G, Huang Y, Cheneval O, Lawrence N, Zhang Z, Fairlie DP, Craik DJ, de Araujo AD, Henriques ST. Development of cell‐penetrating peptide‐based drug leads to inhibit MDMX:p53 and MDM2:p53 interactions. Pept Sci (Hoboken) 2016; 106:853-863. [DOI: 10.1002/bip.22893] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 05/23/2016] [Accepted: 05/31/2016] [Indexed: 12/27/2022]
Affiliation(s)
- Grégoire Philippe
- Institute for Molecular Biosciencethe University of Queensland QLD4072 Australia
| | - Yen‐Hua Huang
- Institute for Molecular Biosciencethe University of Queensland QLD4072 Australia
| | - Olivier Cheneval
- Institute for Molecular Biosciencethe University of Queensland QLD4072 Australia
| | - Nicole Lawrence
- Institute for Molecular Biosciencethe University of Queensland QLD4072 Australia
| | - Zhen Zhang
- Institute for Molecular Biosciencethe University of Queensland QLD4072 Australia
| | - David P Fairlie
- Institute for Molecular Biosciencethe University of Queensland QLD4072 Australia
| | - David J. Craik
- Institute for Molecular Biosciencethe University of Queensland QLD4072 Australia
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212
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Samadikhah HR, Nikkhah M, Hosseinkhani S. Enhancement of cell internalization and photostability of red and green emitter quantum dots upon entrapment in novel cationic nanoliposomes. LUMINESCENCE 2016; 32:517-528. [DOI: 10.1002/bio.3207] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 07/11/2016] [Accepted: 08/02/2016] [Indexed: 01/11/2023]
Affiliation(s)
- Hamid Reza Samadikhah
- Department of Nanobiotechnology, Faculty of Biological Sciences; Tarbiat Modares University; Tehran Iran
| | - Maryam Nikkhah
- Department of Nanobiotechnology, Faculty of Biological Sciences; Tarbiat Modares University; Tehran Iran
| | - Saman Hosseinkhani
- Department of Biochemistry, Faculty of Biological Sciences; Tarbiat Modares University; Tehran Iran
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213
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Antón Z, Landajuela A, Hervás JH, Montes LR, Hernández-Tiedra S, Velasco G, Goñi FM, Alonso A. Human Atg8-cardiolipin interactions in mitophagy: Specific properties of LC3B, GABARAPL2 and GABARAP. Autophagy 2016; 12:2386-2403. [PMID: 27764541 DOI: 10.1080/15548627.2016.1240856] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The phospholipid cardiolipin (CL) has been proposed to play a role in selective mitochondrial autophagy, or mitophagy. CL externalization to the outer mitochondrial membrane would act as a signal for the human Atg8 ortholog subfamily, MAP1LC3 (LC3). The latter would mediate both mitochondrial recognition and autophagosome formation, ultimately leading to removal of damaged mitochondria. We have applied quantitative biophysical techniques to the study of CL interaction with various Atg8 human orthologs, namely LC3B, GABARAPL2 and GABARAP. We have found that LC3B interacts preferentially with CL over other di-anionic lipids, that CL-LC3B binding occurs with positive cooperativity, and that the CL-LC3B interaction relies only partially on electrostatic forces. CL-induced increased membrane fluidity appears also as an important factor helping LC3B to bind CL. The LC3B C terminus remains exposed to the hydrophilic environment after protein binding to CL-enriched membranes. In intact U87MG human glioblastoma cells rotenone-induced autophagy leads to LC3B translocation to mitochondria and subsequent delivery of mitochondria to lysosomes. We have also observed that GABARAP, but not GABARAPL2, interacts with CL in vitro. However neither GABARAP nor GABARAPL2 were translocated to mitochondria in rotenone-treated U87MG cells. Thus the various human Atg8 orthologs might play specific roles in different autophagic processes.
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Affiliation(s)
- Zuriñe Antón
- a Instituto Biofisika (CSIC, UPV/EHU) and Departamento de Bioquímica y Biología Molecular , Universidad del País Vasco , Bilbao , Spain
| | - Ane Landajuela
- a Instituto Biofisika (CSIC, UPV/EHU) and Departamento de Bioquímica y Biología Molecular , Universidad del País Vasco , Bilbao , Spain
| | - Javier H Hervás
- a Instituto Biofisika (CSIC, UPV/EHU) and Departamento de Bioquímica y Biología Molecular , Universidad del País Vasco , Bilbao , Spain
| | - L Ruth Montes
- a Instituto Biofisika (CSIC, UPV/EHU) and Departamento de Bioquímica y Biología Molecular , Universidad del País Vasco , Bilbao , Spain
| | - Sonia Hernández-Tiedra
- b Departamento de Bioquímica y Biología Molecular I , Universidad Complutense , Madrid , Spain.,c Instituto de Investigaciones Sanitarias San Carlos (IdISSC) , Madrid , Spain
| | - Guillermo Velasco
- b Departamento de Bioquímica y Biología Molecular I , Universidad Complutense , Madrid , Spain.,c Instituto de Investigaciones Sanitarias San Carlos (IdISSC) , Madrid , Spain
| | - Felix M Goñi
- a Instituto Biofisika (CSIC, UPV/EHU) and Departamento de Bioquímica y Biología Molecular , Universidad del País Vasco , Bilbao , Spain
| | - Alicia Alonso
- a Instituto Biofisika (CSIC, UPV/EHU) and Departamento de Bioquímica y Biología Molecular , Universidad del País Vasco , Bilbao , Spain
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214
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Landajuela A, Hervás JH, Antón Z, Montes LR, Gil D, Valle M, Rodriguez JF, Goñi FM, Alonso A. Lipid Geometry and Bilayer Curvature Modulate LC3/GABARAP-Mediated Model Autophagosomal Elongation. Biophys J 2016; 110:411-422. [PMID: 26789764 DOI: 10.1016/j.bpj.2015.11.3524] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 11/14/2015] [Accepted: 11/30/2015] [Indexed: 11/29/2022] Open
Abstract
Autophagy, an important catabolic pathway involved in a broad spectrum of human diseases, implies the formation of double-membrane-bound structures called autophagosomes (AP), which engulf material to be degraded in lytic compartments. How APs form, especially how the membrane expands and eventually closes upon itself, is an area of intense research. Ubiquitin-like ATG8 has been related to both membrane expansion and membrane fusion, but the underlying molecular mechanisms are poorly understood. Here, we used two minimal reconstituted systems (enzymatic and chemical conjugation) to compare the ability of human ATG8 homologs (LC3, GABARAP, and GATE-16) to mediate membrane fusion. We found that both enzymatically and chemically lipidated forms of GATE-16 and GABARAP proteins promote extensive membrane tethering and fusion, whereas lipidated LC3 does so to a much lesser extent. Moreover, we characterize the GATE-16/GABARAP-mediated membrane fusion as a phenomenon of full membrane fusion, independently demonstrating vesicle aggregation, intervesicular lipid mixing, and intervesicular mixing of aqueous content, in the absence of vesicular content leakage. Multiple fusion events give rise to large vesicles, as seen by cryo-electron microscopy observations. We also show that both vesicle diameter and selected curvature-inducing lipids (cardiolipin, diacylglycerol, and lyso-phosphatidylcholine) can modulate the fusion process, smaller vesicle diameters and negative intrinsic curvature lipids (cardiolipin, diacylglycerol) facilitating fusion. These results strongly support the hypothesis of a highly bent structural fusion intermediate (stalk) during AP biogenesis and add to the growing body of evidence that identifies lipids as important regulators of autophagy.
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Affiliation(s)
- Ane Landajuela
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - Javier H Hervás
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - Zuriñe Antón
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - L Ruth Montes
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - David Gil
- Structural Biology Unit, Center for Cooperative Research in Biosciences, CIC bioGUNE, Derio, Spain
| | - Mikel Valle
- Structural Biology Unit, Center for Cooperative Research in Biosciences, CIC bioGUNE, Derio, Spain
| | - J Francisco Rodriguez
- Departmento de Biología Molecular y Celular, Centro Nacional de Biotecnología-CSIC, Cantoblanco, Madrid, Spain
| | - Felix M Goñi
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - Alicia Alonso
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain.
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215
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Hanson JM, Gettel DL, Tabaei SR, Jackman J, Kim MC, Sasaki DY, Groves JT, Liedberg B, Cho NJ, Parikh AN. Cholesterol-Enriched Domain Formation Induced by Viral-Encoded, Membrane-Active Amphipathic Peptide. Biophys J 2016; 110:176-87. [PMID: 26745420 DOI: 10.1016/j.bpj.2015.11.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 10/23/2015] [Accepted: 11/17/2015] [Indexed: 12/15/2022] Open
Abstract
The α-helical (AH) domain of the hepatitis C virus nonstructural protein NS5A, anchored at the cytoplasmic leaflet of the endoplasmic reticulum, plays a role in viral replication. However, the peptides derived from this domain also exhibit remarkably broad-spectrum virocidal activity, raising questions about their modes of membrane association. Here, using giant lipid vesicles, we show that the AH peptide discriminates between membrane compositions. In cholesterol-containing membranes, peptide binding induces microdomain formation. By contrast, cholesterol-depleted membranes undergo global softening at elevated peptide concentrations. Furthermore, in mixed populations, the presence of ∼100 nm vesicles of viral dimensions suppresses these peptide-induced perturbations in giant unilamellar vesicles, suggesting size-dependent membrane association. These synergistic composition- and size-dependent interactions explain, in part, how the AH domain might on the one hand segregate molecules needed for viral assembly and on the other hand furnish peptides that exhibit broad-spectrum virocidal activity.
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Affiliation(s)
- Joshua M Hanson
- Biophysics Graduate Group, University of California, Davis, Davis, California
| | - Douglas L Gettel
- Department of Chemical Engineering & Materials Science, University of California, Davis, Davis, California
| | - Seyed R Tabaei
- Centre for Biomimetic Sensor Science, Nanyang Technological University, Singapore; School of Materials Science and Engineering, Nanyang Technological University, Singapore
| | - Joshua Jackman
- Centre for Biomimetic Sensor Science, Nanyang Technological University, Singapore; School of Materials Science and Engineering, Nanyang Technological University, Singapore
| | - Min Chul Kim
- Centre for Biomimetic Sensor Science, Nanyang Technological University, Singapore; School of Materials Science and Engineering, Nanyang Technological University, Singapore
| | - Darryl Y Sasaki
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, California
| | - Jay T Groves
- Chemistry Department, University of California, Berkeley, California; Mechanobiology Institute, National University of Singapore, Singapore
| | - Bo Liedberg
- Centre for Biomimetic Sensor Science, Nanyang Technological University, Singapore; School of Materials Science and Engineering, Nanyang Technological University, Singapore
| | - Nam-Joon Cho
- Centre for Biomimetic Sensor Science, Nanyang Technological University, Singapore; School of Materials Science and Engineering, Nanyang Technological University, Singapore; School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
| | - Atul N Parikh
- Biophysics Graduate Group, University of California, Davis, Davis, California; Department of Chemical Engineering & Materials Science, University of California, Davis, Davis, California; Centre for Biomimetic Sensor Science, Nanyang Technological University, Singapore; School of Materials Science and Engineering, Nanyang Technological University, Singapore; Department of Biomedical Engineering, University of California, Davis, Davis, California.
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216
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Osmotic Dehydration of Liposomal Dispersions: Influence of Particle Size and Electrostatic Deposition of Cold Water Fish Skin Gelatin. FOOD BIOPHYS 2016. [DOI: 10.1007/s11483-016-9456-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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217
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Whelihan MF, Lim MY, Mooberry MJ, Piegore MG, Ilich A, Wogu A, Cai J, Monroe DM, Ataga KI, Mann KG, Key NS. Thrombin generation and cell-dependent hypercoagulability in sickle cell disease. J Thromb Haemost 2016; 14:1941-1952. [PMID: 27430959 DOI: 10.1111/jth.13416] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Indexed: 02/03/2023]
Abstract
Essentials Sickle cell disease is increasingly being recognized as a chronic hypercoagulable state. Thrombin generation is elevated in the whole blood, but not the plasma of sickle cell patients. Whole blood thrombin generation inversely correlates to erythrocyte phosphatidylserine exposure. Acquired protein S deficiency is likely explained by binding of protein S to sickle red cells. Click to hear Dr Hillery discuss coagulation and vascular pathologies in mouse models of sickle cell disease. SUMMARY Introduction Sickle cell disease (SCD) is a hypercoagulable state with chronic activation of coagulation and an increased incidence of thromboembolic events. However, although plasma pre-thrombotic markers such as thrombin-anithrombin complexes and D-dimer are elevated, there is no consensus on whether global assays of thrombin generation in plasma are abnormal in patients with SCD. Based on our recent observation that normal red blood cells (RBCs) contribute to thrombin generation in whole blood, we hypothesized that the cellular components in blood (notably phosphatidylserine-expressing erythrocytes) contribute to enhanced thrombin generation in SCD. Methods Whole blood and plasma thrombin generation assays were performed on blood samples from 25 SCD patients in a non-crisis 'steady state' and 25 healthy race-matched controls. Results Whole blood thrombin generation was significantly elevated in SCD, whereas plasma thrombin generation was paradoxically reduced compared with controls. Surprisingly, whole blood and plasma thrombin generation were both negatively correlated with phosphatidylserine exposure on RBCs. Plasma thrombin generation in the presence of exogenous activated protein C or soluble thrombomodulin revealed deficiencies in the protein C/S anticoagulant pathway in SCD. These global changes were associated with significantly lower plasma protein S activity in SCD that correlated inversely with RBC phosphatidylserine exposure. Conclusion Increased RBC phosphatidylserine exposure in SCD is associated with acquired protein S deficiency. In addition, these data suggest a cellular contribution to thrombin generation in SCD (other than RBC phosphatidylserine exposure) that explains the elevated thrombin generation in whole blood.
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Affiliation(s)
| | - M Y Lim
- Department of Medicine, Chapel Hill, NC, USA
| | | | - M G Piegore
- Department of Medicine, Chapel Hill, NC, USA
| | - A Ilich
- Department of Medicine, Chapel Hill, NC, USA
| | - A Wogu
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - J Cai
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - D M Monroe
- Department of Medicine, Chapel Hill, NC, USA
| | - K I Ataga
- Department of Medicine, Chapel Hill, NC, USA
| | - K G Mann
- Department of Biochemistry, University of Vermont, Burlington, VT, USA
| | - N S Key
- Department of Medicine, Chapel Hill, NC, USA.
- Department of Pathology and Laboratory Medicine, Chapel Hill, NC, USA.
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218
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Wright AJ, Richens JL, Bramble JP, Cathcart N, Kitaev V, O'Shea P, Hudson AJ. Surface-enhanced Raman scattering measurement from a lipid bilayer encapsulating a single decahedral nanoparticle mediated by an optical trap. NANOSCALE 2016; 8:16395-16404. [PMID: 27722713 DOI: 10.1039/c6nr05616d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present a new technique for the study of model membranes on the length-scale of a single nano-sized liposome. Silver decahedral nanoparticles have been encapsulated by a model unilamellar lipid bilayer creating nano-sized lipid vesicles. The metal core has two roles (i) increasing the polarizability of vesicles, enabling a single vesicle to be isolated and confined in an optical trap, and (ii) enhancing Raman scattering from the bilayer, via the high surface-plasmon field at the sharp vertices of the decahedral particles. Combined this has allowed us to measure a Raman fingerprint from a single vesicle of 50 nm-diameter, containing just ∼104 lipid molecules in a bilayer membrane over a surface area of <0.01 μm2, equivalent to a volume of approximately 1 zepto-litre. Raman scattering is a weak and inefficient process and previous studies have required either a substantially larger bilayer area in order to obtain a detectable signal, or the tagging of lipid molecules with a chromophore to provide an indirect probe of the bilayer. Our approach is fully label-free and bio-compatible and, in the future, it will enable much more localized studies of the heterogeneous structure of lipid bilayers and of membrane-bound components than is currently possible.
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Affiliation(s)
- A J Wright
- Department of Electrical and Electronic Engineering, University of Nottingham, Nottingham, NG7 2RD, UK.
| | - J L Richens
- Faculty of Pharmaceutical Sciences, 2405 Wesbrook Mall, Vancouver, BC Canada, V6T 1Z3
| | - J P Bramble
- Faculty of Pharmaceutical Sciences, 2405 Wesbrook Mall, Vancouver, BC Canada, V6T 1Z3
| | - N Cathcart
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada
| | - V Kitaev
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada
| | - P O'Shea
- Faculty of Pharmaceutical Sciences, 2405 Wesbrook Mall, Vancouver, BC Canada, V6T 1Z3
| | - A J Hudson
- Department of Chemistry, University of Leicester, Leicester, LE1 7RH, UK
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219
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Thewalt J, Tieleman DP. Biophysical experiments and simulation in nanoparticle-based drug delivery systems. J Drug Target 2016; 24:768-773. [DOI: 10.1080/1061186x.2016.1221957] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Jenifer Thewalt
- Department of Physics, Simon Fraser University, Burnaby, Canada
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada
| | - D. Peter Tieleman
- Department of Biological Sciences, Centre for Molecular Simulation, University of Calgary, Calgary, Canada
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220
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Tam YK, Madden TD, Hope MJ. Pieter Cullis’ quest for a lipid-based, fusogenic delivery system for nucleic acid therapeutics: success with siRNA so what about mRNA? J Drug Target 2016; 24:774-779. [DOI: 10.1080/1061186x.2016.1221955] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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221
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Taylor R, Butt K, Scott B, Zhang T, Muraih JK, Mintzer E, Taylor S, Palmer M. Two successive calcium-dependent transitions mediate membrane binding and oligomerization of daptomycin and the related antibiotic A54145. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1999-2005. [DOI: 10.1016/j.bbamem.2016.05.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 05/07/2016] [Accepted: 05/24/2016] [Indexed: 01/09/2023]
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222
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Bianchi F, Klooster JSV', Ruiz SJ, Luck K, Pols T, Urbatsch IL, Poolman B. Asymmetry in inward- and outward-affinity constant of transport explain unidirectional lysine flux in Saccharomyces cerevisiae. Sci Rep 2016; 6:31443. [PMID: 27550794 PMCID: PMC4993999 DOI: 10.1038/srep31443] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/20/2016] [Indexed: 02/01/2023] Open
Abstract
The import of basic amino acids in Saccharomyces cerevisiae has been reported to be unidirectional, which is not typical of how secondary transporters work. Since studies of energy coupling and transport kinetics are complicated in vivo, we purified the major lysine transporter (Lyp1) of yeast and reconstituted the protein into lipid vesicles. We show that the Michaelis constant (KM) of transport from out-to-in is well in the millimolar range and at least 3 to 4-orders of magnitude higher than that of transport in the opposite direction, disfavoring the efflux of solute via Lyp1. We also find that at low values of the proton motive force, the transport by Lyp1 is comparatively slow. We benchmarked the properties of eukaryotic Lyp1 to that of the prokaryotic homologue LysP and find that LysP has a similar KM for transport from in-to-out and out-to-in, consistent with rapid influx and efflux. We thus explain the previously described unidirectional nature of lysine transport in S. cerevisiae by the extraordinary kinetics of Lyp1 and provide a mechanism and rationale for previous observations. The high asymmetry in transport together with secondary storage in the vacuole allow the cell to accumulate basic amino acids to very high levels.
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Affiliation(s)
- Frans Bianchi
- Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Joury S van 't Klooster
- Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Stephanie J Ruiz
- Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Katja Luck
- Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Tjeerd Pols
- Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Ina L Urbatsch
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Bert Poolman
- Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Nijenborgh 4, 9747 AG Groningen, The Netherlands.,Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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223
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The retina as an early biomarker of neurodegeneration in a rotenone-induced model of Parkinson's disease: evidence for a neuroprotective effect of rosiglitazone in the eye and brain. Acta Neuropathol Commun 2016; 4:86. [PMID: 27535749 PMCID: PMC4989531 DOI: 10.1186/s40478-016-0346-z] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 07/11/2016] [Indexed: 12/21/2022] Open
Abstract
Parkinson’s Disease (PD) is the second most common neurodegenerative disease worldwide, affecting 1 % of the population over 65 years of age. Dopaminergic cell death in the substantia nigra and accumulation of Lewy bodies are the defining neuropathological hallmarks of the disease. Neuronal death and dysfunction have been reported in other central nervous system regions, including the retina. Symptoms of PD typically manifest only when more than 70 % of dopaminergic cells are lost, and the definitive diagnosis of PD can only be made histologically at post-mortem, with few biomarkers available. In this study, a rotenone-induced rodent model of PD was employed to investigate retinal manifestations in PD and their usefulness in assessing the efficacy of a novel therapeutic intervention with a liposomal formulation of the PPAR-γ (Peroxisome proliferator-activated receptor gamma) agonist rosiglitazone. Retinal assessment was performed using longitudinal in vivo imaging with DARC (detection of apoptosing retinal cells) and OCT (optical coherence tomography) technologies and revealed increased RGCs (Retinal Ganglion Cells) apoptosis and a transient swelling of the retinal layers at day 20 of the rotenone insult. Follow-up of this model demonstrated characteristic histological neurodegenerative changes in the substantia nigra and striatum by day 60, suggesting that retinal changes precede the “traditional” pathological manifestations of PD. The therapeutic effect of systemic administration of different formulations of rosiglitazone was then evaluated, both in the retina and the brain. Of all treatment regimen tested, sustained release administration of liposome-encapsulated rosiglitazone proved to be the most potent therapeutic strategy, as evidenced by its significant neuroprotective effect on retinal neurons at day 20, and on nigrostriatal neurons at day 60, provided convincing evidence for its potential as a treatment for PD. Our results demonstrate significant retinal changes occurring in this model of PD. We show that rosiglitazone can efficiently protect retinal neurons from the rotenone insult, and that systemic administration of liposome-encapsulated rosiglitazone has an enhanced neuroprotective effect on the retina and CNS (Central Nervous System). To our knowledge, this is the first in vivo evidence of RGCs loss and early retinal thickness alterations in a PD model. Together, these findings suggest that retinal changes may be a good surrogate biomarker for PD, which may be used to assess new treatments both experimentally and clinically.
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224
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Zhang Q, Morgan SP, O’Shea P, Mather ML. Ultrasound Induced Fluorescence of Nanoscale Liposome Contrast Agents. PLoS One 2016; 11:e0159742. [PMID: 27467748 PMCID: PMC4965150 DOI: 10.1371/journal.pone.0159742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 07/07/2016] [Indexed: 11/19/2022] Open
Abstract
A new imaging contrast agent is reported that provides an increased fluorescent signal upon application of ultrasound (US). Liposomes containing lipids labelled with pyrene were optically excited and the excimer fluorescence emission intensity was detected in the absence and presence of an ultrasound field using an acousto-fluorescence setup. The acousto-fluorescence dynamics of liposomes containing lipids with pyrene labelled on the fatty acid tail group (PyPC) and the head group (PyPE) were compared. An increase in excimer emission intensity following exposure to US was observed for both cases studied. The increased intensity and time constants were found to be different for the PyPC and PyPE systems, and dependent on the applied US pressure and exposure time. The greatest change in fluorescence intensity (130%) and smallest rise time constant (0.33 s) are achieved through the use of PyPC labelled liposomes. The mechanism underlying the observed increase of the excimer emission intensity in PyPC labelled liposomes is proposed to arise from the "wagging" of acyl chains which involves fast response and requires lower US pressure. This is accompanied by increased lipid lateral diffusivity at higher ultrasound pressures, a mechanism that is also active in the PyPE labelled liposomes.
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Affiliation(s)
- Qimei Zhang
- Advanced Optics Group, Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
| | - Stephen P. Morgan
- Advanced Optics Group, Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
| | - Paul O’Shea
- Cell Biophysics Group, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Melissa L. Mather
- Advanced Optics Group, Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
- Institute for Science and Technology in Medicine, Keele University, Stoke-on-Trent, United Kingdom
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225
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Jeevanandam J, Chan YS, Danquah MK. Nano-formulations of drugs: Recent developments, impact and challenges. Biochimie 2016; 128-129:99-112. [PMID: 27436182 DOI: 10.1016/j.biochi.2016.07.008] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 07/15/2016] [Indexed: 12/13/2022]
Abstract
Nano-formulations of medicinal drugs have attracted the interest of many researchers for drug delivery applications. These nano-formulations enhance the properties of conventional drugs and are specific to the targeted delivery site. Dendrimers, polymeric nanoparticles, liposomes, nano-emulsions and micelles are some of the nano-formulations that are gaining prominence in pharmaceutical industry for enhanced drug formulation. Wide varieties of synthesis methods are available for the preparation of nano-formulations to deliver drugs in biological system. The choice of synthesis methods depend on the size and shape of particulate formulation, biochemical properties of drug, and the targeted site. This article discusses recent developments in nano-formulation and the progressive impact on pharmaceutical research and industries. Additionally, process challenges relating to consistent generation of nano-formulations for drug delivery are discussed.
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Affiliation(s)
- Jaison Jeevanandam
- Department of Chemical Engineering, Faculty of Engineering and Science, Curtin University, CDT 250, 98009, Miri, Sarawak, Malaysia
| | - Yen San Chan
- Department of Chemical Engineering, Faculty of Engineering and Science, Curtin University, CDT 250, 98009, Miri, Sarawak, Malaysia.
| | - Michael K Danquah
- Department of Chemical Engineering, Faculty of Engineering and Science, Curtin University, CDT 250, 98009, Miri, Sarawak, Malaysia
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226
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Migliolo L, Felício MR, Cardoso MH, Silva ON, Xavier MAE, Nolasco DO, de Oliveira AS, Roca-Subira I, Vila Estape J, Teixeira LD, Freitas SM, Otero-Gonzalez AJ, Gonçalves S, Santos NC, Franco OL. Structural and functional evaluation of the palindromic alanine-rich antimicrobial peptide Pa -MAP2. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1488-98. [DOI: 10.1016/j.bbamem.2016.04.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 03/22/2016] [Accepted: 04/05/2016] [Indexed: 11/26/2022]
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227
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Lousa D, Pinto ART, Victor BL, Laio A, Veiga AS, Castanho MARB, Soares CM. Fusing simulation and experiment: The effect of mutations on the structure and activity of the influenza fusion peptide. Sci Rep 2016; 6:28099. [PMID: 27302370 PMCID: PMC4908596 DOI: 10.1038/srep28099] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 05/27/2016] [Indexed: 01/26/2023] Open
Abstract
During the infection process, the influenza fusion peptide (FP) inserts into the host membrane, playing a crucial role in the fusion process between the viral and host membranes. In this work we used a combination of simulation and experimental techniques to analyse the molecular details of this process, which are largely unknown. Although the FP structure has been obtained by NMR in detergent micelles, there is no atomic structure information in membranes. To answer this question, we performed bias-exchange metadynamics (BE-META) simulations, which showed that the lowest energy states of the membrane-inserted FP correspond to helical-hairpin conformations similar to that observed in micelles. BE-META simulations of the G1V, W14A, G12A/G13A and G4A/G8A/G16A/G20A mutants revealed that all the mutations affect the peptide’s free energy landscape. A FRET-based analysis showed that all the mutants had a reduced fusogenic activity relative to the WT, in particular the mutants G12A/G13A and G4A/G8A/G16A/G20A. According to our results, one of the major causes of the lower activity of these mutants is their lower membrane affinity, which results in a lower concentration of peptide in the bilayer. These findings contribute to a better understanding of the influenza fusion process and open new routes for future studies.
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Affiliation(s)
- Diana Lousa
- ITQB, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Antónia R T Pinto
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Bruno L Victor
- ITQB, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Alessandro Laio
- SISSA/ISAS, Statistical and biological physics, Via Beirut 2-4 Trieste, Italy
| | - Ana S Veiga
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Miguel A R B Castanho
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Cláudio M Soares
- ITQB, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
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228
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Artificial membranes for membrane protein purification, functionality and structure studies. Biochem Soc Trans 2016; 44:877-82. [DOI: 10.1042/bst20160054] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Indexed: 11/17/2022]
Abstract
Membrane proteins represent one of the most important targets for pharmaceutical companies. Unfortunately, technical limitations have long been a major hindrance in our understanding of the function and structure of such proteins. Recent years have seen the refinement of classical approaches and the emergence of new technologies that have resulted in a significant step forward in the field of membrane protein research. This review summarizes some of the current techniques used for studying membrane proteins, with overall advantages and drawbacks for each method.
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229
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Impact of Antioxidants on Cardiolipin Oxidation in Liposomes: Why Mitochondrial Cardiolipin Serves as an Apoptotic Signal? OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:8679469. [PMID: 27313834 PMCID: PMC4899610 DOI: 10.1155/2016/8679469] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Revised: 02/29/2016] [Accepted: 03/17/2016] [Indexed: 01/08/2023]
Abstract
Molecules of mitochondrial cardiolipin (CL) get selectively oxidized upon oxidative stress, which triggers the intrinsic apoptotic pathway. In a chemical model most closely resembling the mitochondrial membrane-liposomes of pure bovine heart CL-we compared ubiquinol-10, ubiquinol-6, and alpha-tocopherol, the most widespread naturally occurring antioxidants, with man-made, quinol-based amphiphilic antioxidants. Lipid peroxidation was induced by addition of an azo initiator in the absence and presence of diverse antioxidants, respectively. The kinetics of CL oxidation was monitored via formation of conjugated dienes at 234 nm. We found that natural ubiquinols and ubiquinol-based amphiphilic antioxidants were equally efficient in protecting CL liposomes from peroxidation; the chromanol-based antioxidants, including alpha-tocopherol, were 2-3 times less efficient. Amphiphilic antioxidants, but not natural ubiquinols and alpha-tocopherol, were able, additionally, to protect the CL bilayer from oxidation by acting from the water phase. We suggest that the previously reported therapeutic efficiency of mitochondrially targeted amphiphilic antioxidants is owing to their ability to protect those CL molecules that are inaccessible to natural hydrophobic antioxidants, being trapped within respiratory supercomplexes. The high susceptibility of such occluded CL molecules to oxidation may have prompted their recruitment as apoptotic signaling molecules by nature.
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230
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Carugo D, Bottaro E, Owen J, Stride E, Nastruzzi C. Liposome production by microfluidics: potential and limiting factors. Sci Rep 2016; 6:25876. [PMID: 27194474 PMCID: PMC4872163 DOI: 10.1038/srep25876] [Citation(s) in RCA: 228] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 04/22/2016] [Indexed: 12/24/2022] Open
Abstract
This paper provides an analysis of microfluidic techniques for the production of nanoscale lipid-based vesicular systems. In particular we focus on the key issues associated with the microfluidic production of liposomes. These include, but are not limited to, the role of lipid formulation, lipid concentration, residual amount of solvent, production method (including microchannel architecture), and drug loading in determining liposome characteristics. Furthermore, we propose microfluidic architectures for the mass production of liposomes with a view to potential industrial translation of this technology.
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Affiliation(s)
- Dario Carugo
- Institute of Biomedical Engineering, Department of Engineering Science, Old Road Campus Research Building, University of Oxford, Oxford, United Kingdom.,Mechatronics and Bioengineering Science research groups, Faculty of Engineering and the Environment, University of Southampton, Southampton, United Kingdom
| | - Elisabetta Bottaro
- Department of Life Science and Biotechnology, University of Ferrara, Italy
| | - Joshua Owen
- Institute of Biomedical Engineering, Department of Engineering Science, Old Road Campus Research Building, University of Oxford, Oxford, United Kingdom
| | - Eleanor Stride
- Institute of Biomedical Engineering, Department of Engineering Science, Old Road Campus Research Building, University of Oxford, Oxford, United Kingdom
| | - Claudio Nastruzzi
- Department of Life Science and Biotechnology, University of Ferrara, Italy
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231
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Yoshimoto M, Yamada J, Baba M, Walde P. Enhanced Heat Stability of α-Chymotrypsin through Single-Enzyme Confinement in Attoliter Liposomes. Chembiochem 2016; 17:1221-4. [DOI: 10.1002/cbic.201600150] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Makoto Yoshimoto
- Department of Applied Molecular Bioscience; Yamaguchi University; 2-16-1 Tokiwadai Ube 755-8611 Japan
| | - Jun Yamada
- Department of Applied Molecular Bioscience; Yamaguchi University; 2-16-1 Tokiwadai Ube 755-8611 Japan
| | - Misaki Baba
- Department of Applied Molecular Bioscience; Yamaguchi University; 2-16-1 Tokiwadai Ube 755-8611 Japan
| | - Peter Walde
- Department of Materials; ETH Zürich; Vladimir-Prelog-Weg 5 8093 Zürich Switzerland
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232
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Barroso MF, Luna MA, Tabares JSF, Delerue-Matos C, Correa NM, Moyano F, Molina PG. Gold nanoparticles covalently assembled onto vesicle structures as possible biosensing platform. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2016; 7:655-663. [PMID: 27335755 PMCID: PMC4902081 DOI: 10.3762/bjnano.7.58] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 04/15/2016] [Indexed: 06/06/2023]
Abstract
In this contribution a strategy is shown to covalently immobilize gold nanoparticles (AuNPs) onto vesicle bilayers with the aim of using this nanomaterial as platform for the future design of immunosensors. A novel methodology for the self-assembly of AuNPs onto large unilamellar vesicle structures is described. The vesicles were formed with 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1-undecanethiol (SH). After, the AuNPs photochemically synthesized in pure glycerol were mixed and anchored onto SH-DOPC vesicles. The data provided by voltammetry, spectrometry and microscopy techniques indicated that the AuNPs were successfully covalently anchored onto the vesicle bilayer and decorated vesicles exhibit a spherical shape with a size of 190 ± 10 nm. The developed procedure is easy, rapid and reproducible to start designing a possible immunosensor by using environmentally friendly procedures.
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Affiliation(s)
- M Fátima Barroso
- Departamento de Química. Facultad de Ciencias Exactas, Físico-Químicas y Naturales. Universidad Nacional de Río Cuarto. Agencia Postal Nº 3 - (5800) Río Cuarto, Argentina
- REQUIMTE/LAQV, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida 431, 4200-072 Porto, Portugal
| | - M Alejandra Luna
- Departamento de Química. Facultad de Ciencias Exactas, Físico-Químicas y Naturales. Universidad Nacional de Río Cuarto. Agencia Postal Nº 3 - (5800) Río Cuarto, Argentina
| | - Juan S Flores Tabares
- Departamento de Química. Facultad de Ciencias Exactas, Físico-Químicas y Naturales. Universidad Nacional de Río Cuarto. Agencia Postal Nº 3 - (5800) Río Cuarto, Argentina
| | - Cristina Delerue-Matos
- REQUIMTE/LAQV, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida 431, 4200-072 Porto, Portugal
| | - N Mariano Correa
- Departamento de Química. Facultad de Ciencias Exactas, Físico-Químicas y Naturales. Universidad Nacional de Río Cuarto. Agencia Postal Nº 3 - (5800) Río Cuarto, Argentina
| | - Fernando Moyano
- Departamento de Química. Facultad de Ciencias Exactas, Físico-Químicas y Naturales. Universidad Nacional de Río Cuarto. Agencia Postal Nº 3 - (5800) Río Cuarto, Argentina
| | - Patricia G Molina
- Departamento de Química. Facultad de Ciencias Exactas, Físico-Químicas y Naturales. Universidad Nacional de Río Cuarto. Agencia Postal Nº 3 - (5800) Río Cuarto, Argentina
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233
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Mooberry MJ, Bradford R, Hobl EL, Lin FC, Jilma B, Key NS. Procoagulant microparticles promote coagulation in a factor XI-dependent manner in human endotoxemia. J Thromb Haemost 2016; 14:1031-42. [PMID: 26857798 PMCID: PMC4870121 DOI: 10.1111/jth.13285] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Indexed: 11/30/2022]
Abstract
UNLABELLED Essentials The procoagulant effects of microparticles (MPs) on coagulation in endotoxemia are not known. MPs from endotoxemia volunteers were evaluated for procoagulant activity in a plasma milieu. MPs from endotoxemia volunteers shortened clotting times and enhanced thrombin generation. MP procoagulant effects were mediated in a factor XI-dependent manner. SUMMARY Background Human endotoxemia is characterized by acute inflammation and activation of coagulation, as well as increased numbers of circulating microparticles (MPs). Whether these MPs directly promote coagulation and through which pathway their actions are mediated, however, has not been fully explored. Objectives In this study, we aimed to further characterize endotoxin-induced MPs and their procoagulant properties using several approaches. Methods Enumeration and characterization of MPs were performed using a new-generation flow cytometer. Relative contributions of the extrinsic and intrinsic pathways in MP-mediated procoagulant activity were assessed using plasmas deficient in factor (F) VII or FXI or with blocking antibodies to tissue factor (TF) or FXIa. Results Total MPs and platelet MPs were significantly elevated in plasma at 6 h after infusion of endotoxin in healthy human subjects. MPs isolated from plasma following endotoxin infusion also demonstrated increased TF activity in a reconstituted buffer system. When added to recalcified platelet-poor plasma, these MPs also promoted coagulation, as judged by a decreased clotting time with shortening of the lag time and time to peak thrombin using calibrated automated thrombography (CAT). However, the use of FVII-deficient plasma or blocking antibody to TF did not inhibit these procoagulant effects. In contrast, plasma clotting time was prolonged in FXI-deficient plasma and a blocking antibody to FXIa inhibited all MP-mediated parameters in the CAT assay. Conclusions The initiation of coagulation by cellular TF in endotoxemia is in contrast to (and presumably complemented by) the intrinsic pathway-mediated procoagulant effects of circulating MPs.
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Affiliation(s)
- M J Mooberry
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - R Bradford
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA
| | - E L Hobl
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - F C Lin
- Department of Biostatistics, University of North Carolina, Chapel Hill, NC, USA
| | - B Jilma
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - N S Key
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA
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234
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Mann TH, Seth Childers W, Blair JA, Eckart MR, Shapiro L. A cell cycle kinase with tandem sensory PAS domains integrates cell fate cues. Nat Commun 2016; 7:11454. [PMID: 27117914 PMCID: PMC4853435 DOI: 10.1038/ncomms11454] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 03/22/2016] [Indexed: 11/11/2022] Open
Abstract
All cells must integrate sensory information to coordinate developmental events in space and time. The bacterium Caulobacter crescentus uses two-component phospho-signalling to regulate spatially distinct cell cycle events through the master regulator CtrA. Here, we report that CckA, the histidine kinase upstream of CtrA, employs a tandem-PAS domain sensor to integrate two distinct spatiotemporal signals. Using CckA reconstituted on liposomes, we show that one PAS domain modulates kinase activity in a CckA density-dependent manner, mimicking the stimulation of CckA kinase activity that occurs on its transition from diffuse to densely packed at the cell poles. The second PAS domain interacts with the asymmetrically partitioned second messenger cyclic-di-GMP, inhibiting kinase activity while stimulating phosphatase activity, consistent with the selective inactivation of CtrA in the incipient stalked cell compartment. The integration of these spatially and temporally regulated signalling events within a single signalling receptor enables robust orchestration of cell-type-specific gene regulation. The membrane-bound kinase CckA controls the activity of the Caulobacter crescentus master regulator CtrA, which in turn coordinates asymmetric cell division. Here, the authors show that CckA contains two sensory domains that have distinct sensitivities to fluctuations in cyclic-di-GMP concentration and subcellular niche.
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Affiliation(s)
- Thomas H Mann
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California 94305, USA.,Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305, USA
| | - W Seth Childers
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Jimmy A Blair
- Department of Chemistry, Williams College, Williamstown, Massachusetts 01267, USA
| | - Michael R Eckart
- Stanford Protein and Nucleic Acid Facility, Beckman Center, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Lucy Shapiro
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California 94305, USA
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235
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A polyalanine peptide derived from polar fish with anti-infectious activities. Sci Rep 2016; 6:21385. [PMID: 26916401 PMCID: PMC4768251 DOI: 10.1038/srep21385] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 01/22/2016] [Indexed: 12/13/2022] Open
Abstract
Due to the growing concern about antibiotic-resistant microbial infections, increasing support has been given to new drug discovery programs. A promising alternative to counter bacterial infections includes the antimicrobial peptides (AMPs), which have emerged as model molecules for rational design strategies. Here we focused on the study of Pa-MAP 1.9, a rationally designed AMP derived from the polar fish Pleuronectes americanus. Pa-MAP 1.9 was active against Gram-negative planktonic bacteria and biofilms, without being cytotoxic to mammalian cells. By using AFM, leakage assays, CD spectroscopy and in silico tools, we found that Pa-MAP 1.9 may be acting both on intracellular targets and on the bacterial surface, also being more efficient at interacting with anionic LUVs mimicking Gram-negative bacterial surface, where this peptide adopts α-helical conformations, than cholesterol-enriched LUVs mimicking mammalian cells. Thus, as bacteria present varied physiological features that favor antibiotic-resistance, Pa-MAP 1.9 could be a promising candidate in the development of tools against infections caused by pathogenic bacteria.
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236
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Sato YT, Umezaki K, Sawada S, Mukai SA, Sasaki Y, Harada N, Shiku H, Akiyoshi K. Engineering hybrid exosomes by membrane fusion with liposomes. Sci Rep 2016; 6:21933. [PMID: 26911358 PMCID: PMC4766490 DOI: 10.1038/srep21933] [Citation(s) in RCA: 408] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 02/03/2016] [Indexed: 12/18/2022] Open
Abstract
Exosomes are a valuable biomaterial for the development of novel nanocarriers as functionally advanced drug delivery systems. To control and modify the performance of exosomal nanocarriers, we developed hybrid exosomes by fusing their membranes with liposomes using the freeze–thaw method. Exosomes embedded with a specific membrane protein isolated from genetically modified cells were fused with various liposomes, confirming that membrane engineering methods can be combined with genetic modification techniques. Cellular uptake studies performed using the hybrid exosomes revealed that the interactions between the developed exosomes and cells could be modified by changing the lipid composition or the properties of the exogenous lipids. These results suggest that the membrane-engineering approach reported here offers a new strategy for developing rationally designed exosomes as hybrid nanocarriers for use in advanced drug delivery systems.
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Affiliation(s)
- Yuko T Sato
- JST-ERATO, Akiyoshi Bio-nanotransporter Project, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Kaori Umezaki
- JST-ERATO, Akiyoshi Bio-nanotransporter Project, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Shinichi Sawada
- JST-ERATO, Akiyoshi Bio-nanotransporter Project, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.,Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Sada-atsu Mukai
- JST-ERATO, Akiyoshi Bio-nanotransporter Project, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.,Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Yoshihiro Sasaki
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Naozumi Harada
- Department of Immuno-Gene Therapy, Graduate School of Medicine, Mie University, Tsu 514-8507, Japan
| | - Hiroshi Shiku
- Department of Immuno-Gene Therapy, Graduate School of Medicine, Mie University, Tsu 514-8507, Japan
| | - Kazunari Akiyoshi
- JST-ERATO, Akiyoshi Bio-nanotransporter Project, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.,Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
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237
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Hollmann A, Martínez M, Noguera ME, Augusto MT, Disalvo A, Santos NC, Semorile L, Maffía PC. Role of amphipathicity and hydrophobicity in the balance between hemolysis and peptide-membrane interactions of three related antimicrobial peptides. Colloids Surf B Biointerfaces 2016; 141:528-536. [PMID: 26896660 DOI: 10.1016/j.colsurfb.2016.02.003] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 01/30/2016] [Accepted: 02/02/2016] [Indexed: 11/30/2022]
Abstract
Cationic antimicrobial peptides (CAMPs) represent important self defense molecules in many organisms, including humans. These peptides have a broad spectrum of activities, killing or neutralizing many Gram-negative and Gram-positive bacteria. The emergence of multidrug resistant microbes has stimulated research on the development of alternative antibiotics. In the search for new antibiotics, cationic antimicrobial peptides (CAMPs) offer a viable alternative to conventional antibiotics, as they physically disrupt the bacterial membranes, leading to lysis of microbial membranes and eventually cell death. In particular, the group of linear α-helical cationic peptides has attracted increasing interest from clinical as well as basic research during the last decade. In this work, we studied the biophysical and microbiological characteristics of three new designed CAMPs. We modified a previously studied CAMP sequence, in order to increase or diminish the hydrophobic face, changing the position of two lysines or replacing three leucines, respectively. These mutations modified the hydrophobic moment of the resulting peptides and allowed us to study the importance of this parameter in the membrane interactions of the peptides. The structural properties of the peptides were also correlated with their membrane-disruptive abilities, antimicrobial activities and hemolysis of human red blood cells.
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Affiliation(s)
- Axel Hollmann
- Laboratory of Molecular Microbiology, Institute of Basic and Applied Microbiology, National University of Quilmes, Bernal, Buenos Aires, Argentina; Laboratory of Biointerfaces and Biomimetic Systems, CITSE, National University of Santiago del Estero-CONICET, Santiago del Estero, Argentina; Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisbon, Portugal
| | - Melina Martínez
- Laboratory of Molecular Microbiology, Institute of Basic and Applied Microbiology, National University of Quilmes, Bernal, Buenos Aires, Argentina
| | - Martín E Noguera
- Instituto de Química y Fisicoquímica Biológicas, CONICET-University of Buenos Aires, Buenos Aires, Argentina
| | - Marcelo T Augusto
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisbon, Portugal
| | - Anibal Disalvo
- Laboratory of Biointerfaces and Biomimetic Systems, CITSE, National University of Santiago del Estero-CONICET, Santiago del Estero, Argentina
| | - Nuno C Santos
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisbon, Portugal
| | - Liliana Semorile
- Laboratory of Molecular Microbiology, Institute of Basic and Applied Microbiology, National University of Quilmes, Bernal, Buenos Aires, Argentina
| | - Paulo C Maffía
- Laboratory of Molecular Microbiology, Institute of Basic and Applied Microbiology, National University of Quilmes, Bernal, Buenos Aires, Argentina.
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238
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Paiva TO, Bastos AEP, Marquês JT, Viana AS, Lima PA, de Almeida RFM. m-Cresol affects the lipid bilayer in membrane models and living neurons. RSC Adv 2016. [DOI: 10.1039/c6ra20337j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A preferential interaction of m-cresol with high dipole-potential cholesterol/sphingomyelin-enriched lipid domains jeopardizes membrane integrity, explaining the toxicity of m-cresol-containing insulin formulations.
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Affiliation(s)
- T. O. Paiva
- Centro de Química e Bioquímica
- DQB
- Faculdade de Ciências da Universidade de Lisboa
- 1749-016 Lisboa
- Portugal
| | - A. E. P. Bastos
- Centro de Química e Bioquímica
- DQB
- Faculdade de Ciências da Universidade de Lisboa
- 1749-016 Lisboa
- Portugal
| | - J. T. Marquês
- Centro de Química e Bioquímica
- DQB
- Faculdade de Ciências da Universidade de Lisboa
- 1749-016 Lisboa
- Portugal
| | - A. S. Viana
- Centro de Química e Bioquímica
- DQB
- Faculdade de Ciências da Universidade de Lisboa
- 1749-016 Lisboa
- Portugal
| | - P. A. Lima
- NOVA Medical School
- Faculdade de Ciências Médicas da Universidade Nova de Lisboa
- 1169-056 Lisboa
- Portugal
| | - R. F. M. de Almeida
- Centro de Química e Bioquímica
- DQB
- Faculdade de Ciências da Universidade de Lisboa
- 1749-016 Lisboa
- Portugal
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239
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Jackman JA, Kim MC, Zhdanov VP, Cho NJ. Relationship between vesicle size and steric hindrance influences vesicle rupture on solid supports. Phys Chem Chem Phys 2016; 18:3065-72. [DOI: 10.1039/c5cp06786c] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Although it is thermodynamically favorable for adsorbed vesicles to rupture with increasing vesicle size, this study demonstrates that steric hindrance acts as a kinetic barrier to impede large vesicles from rupturing.
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Affiliation(s)
- Joshua A. Jackman
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore
- Centre for Biomimetic Sensor Science
- Nanyang Technological University
| | - Min Chul Kim
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore
- Centre for Biomimetic Sensor Science
- Nanyang Technological University
| | - Vladimir P. Zhdanov
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore
- Centre for Biomimetic Sensor Science
- Nanyang Technological University
| | - Nam-Joon Cho
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore
- Centre for Biomimetic Sensor Science
- Nanyang Technological University
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240
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Cholesterol as a natural probe for free radical-mediated lipid peroxidation in biological membranes and lipoproteins. J Chromatogr B Analyt Technol Biomed Life Sci 2015; 1019:202-9. [PMID: 26778710 DOI: 10.1016/j.jchromb.2015.12.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 12/17/2015] [Accepted: 12/18/2015] [Indexed: 11/20/2022]
Abstract
We describe a relatively convenient and reliable procedure for assessing the magnitude of free radical-mediated (chain) lipid peroxidation in biological systems. The approach is based on use of radiolabeled cholesterol ([(14)C]Ch) as a probe and determination of well-resolved oxidation intermediates/products ([(14)C]ChOX species), using high performance thin layer chromatography with phorphorimaging detection (HPTLC-PI). In a lipid hydroperoxide-primed liposomal test system treated with ascorbate and a lipophilic iron chelate, the following well-resolved [(14)C]ChOX are detected and quantified: 7α/7β-OOH, 7α/7β-OH, and 5,6-epoxide, their levels increasing with incubation time at 37°C. [(14)C]Ch also serves as an excellent probe for lipid peroxidation in lipoproteins and plasma membranes of mammalian cells. Because this approach utilizes Ch as a natural in situ probe, it eliminates potential artifacts associated with artificial probes such as spin traps and fluorophores.
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241
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Ambroggio EE, Caruso B, Villarreal MA, Raussens V, Fidelio GD. Reversing the peptide sequence impacts on molecular surface behaviour. Colloids Surf B Biointerfaces 2015; 139:25-32. [PMID: 26700230 DOI: 10.1016/j.colsurfb.2015.12.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 11/20/2015] [Accepted: 12/02/2015] [Indexed: 01/01/2023]
Abstract
The protein's primary structure has all the information for specific protein/peptide folding and, in many cases, can define specific amphiphilic regions along molecules that are important for interaction with membranes. In order to shed light on how peptide sequence is important for the surface properties of amphiphilic peptides, we designed three pairs of peptides with the following characteristics: (1) all molecules have the same hydrophobic residues; (2) the couples differ from each other in their hydrophilic amino acids: positively, negatively and non-charged; (3) each pair has the same residues (same global molecular hydrophobicity) but the primary structure is reversed in comparison to its partner (retro-isomer), giving a molecule with a hydrophilic N or C-terminus and a hydrophobic C or N-terminus. Using the Langmuir monolayer approach, we observed that sequence reversal has a central role in the lateral stability of peptide monolayers, in the ability of the molecules to partition into the air-water interface and in the rheological properties of peptide films, whereas the peptide's secondary structure, determined by ATR-FTIR, was the same for all peptides. Reversing the sequence also gives a differential way of peptide/lipid interaction when peptides are in the presence of POPC lipid bilayers. Our results show how sequence inversion confers a distinctive peptide surface behaviour and lipid interaction for molecules with a similar structure.
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Affiliation(s)
- Ernesto E Ambroggio
- CIQUIBIC, CONICET, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina.
| | - Benjamín Caruso
- CIQUIBIC, CONICET, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina
| | - Marcos A Villarreal
- Instituto de Investigaciones en Físico-Química de Córdoba (INFIQC), CONICET, Departamento de Matemática y Física, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina
| | - Vincent Raussens
- Centre for Structural Biology and Bioinformatics, Laboratory for Structure and Function of Biological Membranes, Universit é Libre de Bruxelles, CP 206/02, Blvd. du Triomphe, B-1050 Brussels, Belgium
| | - Gerardo D Fidelio
- CIQUIBIC, CONICET, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina
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242
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Ibarguren M, Bomans PHH, Ruiz-Mirazo K, Frederik PM, Alonso A, Goñi FM. Thermally-induced aggregation and fusion of protein-free lipid vesicles. Colloids Surf B Biointerfaces 2015; 136:545-52. [PMID: 26454544 DOI: 10.1016/j.colsurfb.2015.09.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 08/21/2015] [Accepted: 09/24/2015] [Indexed: 12/11/2022]
Abstract
Membrane fusion is an important phenomenon in cell biology and pathology. This phenomenon can be modeled using vesicles of defined size and lipid composition. Up to now fusion models typically required the use of chemical (polyethyleneglycol, cations) or enzymatic catalysts (phospholipases). We present here a model of lipid vesicle fusion induced by heat. Large unilamellar vesicles consisting of a phospholipid (dioleoylphosphatidylcholine), cholesterol and diacylglycerol in a 43:57:3 mol ratio were employed. In this simple system, fusion was the result of thermal fluctuations, above 60 °C. A similar system containing phospholipid and cholesterol but no diacylglycerol was observed to aggregate at and above 60 °C, in the absence of fusion. Vesicle fusion occurred under our experimental conditions only when (31)P NMR and cryo-transmission electron microscopy of the lipid mixtures used in vesicle preparation showed non-lamellar lipid phase formation (hexagonal and cubic). Non-lamellar structures are probably the result of lipid reassembly of the products of individual fusion events, or of fusion intermediates. A temperature-triggered mechanism of lipid reassembly might have occurred at various stages of protocellular evolution.
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Affiliation(s)
- Maitane Ibarguren
- Unidad de Biofísica (Centro Mixto CSIC, UPV/EHU), and Departamento de Bioquímica, Universidad del País Vasco, Apto. 644, 48080 Bilbao, Spain.
| | - Paul H H Bomans
- Soft Matter CryoTEM Research Unit, Laboratory for Materials and Interface Chemistry, P.O. Box 513, 5600MB Eindhoven, The Netherlands.
| | - Kepa Ruiz-Mirazo
- Unidad de Biofísica (Centro Mixto CSIC, UPV/EHU), and Departamento de Bioquímica, Universidad del País Vasco, Apto. 644, 48080 Bilbao, Spain; Logic and Philosophy of Science Department, University of the Basque Country, Spain.
| | - Peter M Frederik
- Soft Matter CryoTEM Research Unit, Laboratory for Materials and Interface Chemistry, P.O. Box 513, 5600MB Eindhoven, The Netherlands.
| | - Alicia Alonso
- Unidad de Biofísica (Centro Mixto CSIC, UPV/EHU), and Departamento de Bioquímica, Universidad del País Vasco, Apto. 644, 48080 Bilbao, Spain.
| | - Félix M Goñi
- Unidad de Biofísica (Centro Mixto CSIC, UPV/EHU), and Departamento de Bioquímica, Universidad del País Vasco, Apto. 644, 48080 Bilbao, Spain.
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243
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Antimicrobial Peptide CMA3 Derived from the CA-MA Hybrid Peptide: Antibacterial and Anti-inflammatory Activities with Low Cytotoxicity and Mechanism of Action in Escherichia coli. Antimicrob Agents Chemother 2015; 60:495-506. [PMID: 26552969 DOI: 10.1128/aac.01998-15] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/28/2015] [Indexed: 12/20/2022] Open
Abstract
CA-MA is a hybrid antimicrobial peptide (AMP) derived from two naturally occurring AMPs, cecropin A and magainin 2. CA-MA shows strong antimicrobial activity against Gram-negative and Gram-positive bacteria but also exhibits cytotoxicity toward mammalian cells. Our objective was to identify CA-MA analogues with reduced cytotoxicity by systematic replacement of amino acids with positively charged R groups (His and Lys), aliphatic R groups (Leu), or polar R groups (Glu). Among the CA-MA analogues studied (CMA1 to -6), CMA3 showed the strongest antimicrobial activity, including against drug-resistant Escherichia coli and Pseudomonas aeruginosa strains isolated from hospital patients. CMA3 appeared to act by inducing pore formation (toroidal model) in the bacterial membrane. In cytotoxicity assays, CMA3 showed little cytotoxicity toward human red blood cells (hRBCs) or HaCaT cells. Additionally, no fluorescence was released from small or giant unilamellar vesicles exposed to 60 μM CMA3 for 80 s, whereas fluorescence was released within 35 s upon exposure to CA-MA. CMA3 also exerted strong lipopolysaccharide (LPS)-neutralizing activity in RAW 264.7 cells, and BALB/c mice exposed to LPS after infection by Escherichia coli showed improved survival after administration of one 0.5-mg/kg of body weight or 1-mg/kg dose of CMA3. Finally, in a mouse model of septic shock, CMA3 reduced the levels of proinflammatory factors, including both nitric oxide and white blood cells, and correspondingly reduced lung tissue damage. This study suggests that CMA3 is an antimicrobial/antiendotoxin peptide that could serve as the basis for the development of anti-inflammatory and/or antimicrobial agents with low cytotoxicity.
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244
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Lete MG, Sot J, Gil D, Valle M, Medina M, Goñi FM, Alonso A. Histones cause aggregation and fusion of lipid vesicles containing phosphatidylinositol-4-phosphate. Biophys J 2015; 108:863-871. [PMID: 25692591 DOI: 10.1016/j.bpj.2014.12.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 12/07/2014] [Accepted: 12/09/2014] [Indexed: 12/13/2022] Open
Abstract
In a previous article, we demonstrated that histones (H1 or histone octamers) interact with negatively charged bilayers and induce extensive aggregation of vesicles containing phosphatidylinositol-4-phosphate (PIP) and, to a lesser extent, vesicles containing phosphatidylinositol (PI). Here, we found that vesicles containing PIP, but not those containing PI, can undergo fusion induced by histones. Fusion was demonstrated through the observation of intervesicular mixing of total lipids and inner monolayer lipids, and by ultrastructural and confocal microscopy studies. Moreover, in both PI- and PIP-containing vesicles, histones caused permeabilization and release of vesicular aqueous contents, but the leakage mechanism was different (all-or-none for PI and graded release for PIP vesicles). These results indicate that histones could play a role in the remodeling of the nuclear envelope that takes place during the mitotic cycle.
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Affiliation(s)
- Marta G Lete
- Unidad de Biofísica (CSIC, UPV/EHU), Universidad del País Vasco, Leioa, Spain; Departamento de Bioquímica, Universidad del País Vasco, Leioa, Spain
| | - Jesus Sot
- Unidad de Biofísica (CSIC, UPV/EHU), Universidad del País Vasco, Leioa, Spain; Departamento de Bioquímica, Universidad del País Vasco, Leioa, Spain
| | - David Gil
- Structural Biology Unit, Center for Cooperative Research in Biosciences, CIC bioGUNE, Derio, Spain
| | - Mikel Valle
- Structural Biology Unit, Center for Cooperative Research in Biosciences, CIC bioGUNE, Derio, Spain
| | - Milagros Medina
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain; Instituto de Biocomputación y Física de Sistemas Complejos, Unidad Asociada BIFI-IQFR, Universidad de Zaragoza, Zaragoza, Spain
| | - Felix M Goñi
- Unidad de Biofísica (CSIC, UPV/EHU), Universidad del País Vasco, Leioa, Spain; Departamento de Bioquímica, Universidad del País Vasco, Leioa, Spain
| | - Alicia Alonso
- Unidad de Biofísica (CSIC, UPV/EHU), Universidad del País Vasco, Leioa, Spain; Departamento de Bioquímica, Universidad del País Vasco, Leioa, Spain.
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245
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Verreault M, Wehbe M, Strutt D, Masin D, Anantha M, Walker D, Chu F, Backstrom I, Kalra J, Waterhouse D, Yapp DT, Bally MB. Determination of an optimal dosing schedule for combining Irinophore C™ and temozolomide in an orthotopic model of glioblastoma. J Control Release 2015; 220:348-357. [PMID: 26528901 DOI: 10.1016/j.jconrel.2015.10.053] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 10/22/2015] [Accepted: 10/28/2015] [Indexed: 12/30/2022]
Abstract
Our laboratory reported that Irinophore C™ (IrC™; a lipid-based nanoparticulate formulation of irinotecan) is effective against an orthotopic model of glioblastoma (GBM) and that treatment with IrC™ was associated with vascular normalization within the tumor. Here, the therapeutic effects of IrC™ when used in combination with temozolomide (TMZ) in concurrent and sequential treatment schedules were tested. It was anticipated that IrC™ engendered vascular normalization would increase the delivery of TMZ to the tumor and that this would be reflected by improved treatment outcomes. The approach compared equally efficacious doses of irinotecan (IRN; 50 mg/kg) and IrC™ (25 mg/kg) in order to determine if there was a unique advantage achieved when combining TMZ with IrC™. The TMZ sensitive U251MG(O) cell line (null expression of O-6-methylguanine-DNA methyltransferase (MGMT)) modified to express the fluorescent protein mKate2 was inoculated orthotopically into NOD.CB17-SCID mice and treatment was initiated 14 days later. Our results demonstrated that IrC™ and TMZ administered concurrently resulted in optimal treatment outcomes, with 50% long term survivors (>180 days) in comparison to 17% long term survivors in animals treated with IRN and TMZ or TMZ alone. Indeed, the different treatments resulted in a 353%, 222% and 280% increase in median survival time (MST) compared to untreated animals for, respectively, IrC™ combined with TMZ, IRN combined with TMZ, and TMZ alone. When TMZ was administered after completion of IRN or IrC™ dosing, an increase in median survival time of 167-174% was observed compared to untreated animals and of 67% and 74%, respectively, when IRN (50 mg/kg) and IrC™ (25mg/kg) were given as single agents. We confirmed in these studies that after completion of the Q7D×3 dosing of IrC™, but not IRN, the tumor-associated vascular was normalized as compared to untreated tumors. Specifically, reductions in the fraction of collagen IV-free CD31 staining (p<0.05) and reductions in tumor vessel diameter were observed in tumors from IrC™-treated animals when compared to tumors from untreated or IRN treated animals. Analysis by transmission electron microscopy of the ultra-structure of tumors from IrC™-treated and untreated animals revealed that tumor-associated vessels from treated animals were smaller, more organized and exhibited a morphology comparable to normal blood vessels. In conclusion, optimal treatment outcomes were achieved when IrC™ and TMZ were administered concurrently, whereas IrC™ followed by TMZ treatment given sequentially did not confer any therapeutic advantage.
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Affiliation(s)
- M Verreault
- Brain and Spine Institute Research Center, 47 Bd de l'Hopital, Paris, 75013, France.
| | - M Wehbe
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver V6T 1Z3, BC, Canada
| | - D Strutt
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada
| | - D Masin
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada
| | - M Anantha
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada
| | - D Walker
- Ultrastructural Imaging, UBC James Hogg Research Laboratories (iCAPTURE), Providence Heart and Lung Institute, St. Paul's Hospital, Rm 166, 1081 Burrard St, Vancouver, BC, Canada
| | - F Chu
- Ultrastructural Imaging, UBC James Hogg Research Laboratories (iCAPTURE), Providence Heart and Lung Institute, St. Paul's Hospital, Rm 166, 1081 Burrard St, Vancouver, BC, Canada
| | - I Backstrom
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada
| | - J Kalra
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada
| | - D Waterhouse
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada
| | - D T Yapp
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver V6T 1Z3, BC, Canada
| | - M B Bally
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver V6T 1Z3, BC, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, 2211 Wesbrook Mall, Vancouver V6T 2B5, BC, Canada; Center for Drug Research and Development, Vancouver V6T 1Z4, BC, Canada.
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246
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Jeong DW, Kim K, Choi MC, Choi SQ. Fluorescence Recovery after Merging a Droplet to Measure the Two-dimensional Diffusion of a Phospholipid Monolayer. J Vis Exp 2015:e53376. [PMID: 26556128 PMCID: PMC4692663 DOI: 10.3791/53376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We introduce a new method to measure the lateral diffusivity of a surfactant monolayer at the fluid-fluid interface, called fluorescence recovery after merging (FRAM). FRAM adopts the same principles as the fluorescence recovery after photobleaching (FRAP) technique, especially for measuring fluorescence recovery after bleaching a specific area, but FRAM uses a drop coalescence instead of photobleaching dye molecules to induce a chemical potential gradient of dye molecules. Our technique has several advantages over FRAP: it only requires a fluorescence microscope rather than a confocal microscope equipped with high power lasers; it is essentially free from the selection of fluorescence dyes; and it has far more freedom to define the measured diffusion area. Furthermore, FRAM potentially provides a route for studying the mixing or inter-diffusion of two different surfactants, when the monolayers at a surface of droplet and at a flat air/water interface are prepared with different species, independently.
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Affiliation(s)
| | - KyuHan Kim
- Information and Electrical Research Institute, KAIST
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Design and membrane-disruption mechanism of charge-enriched AMPs exhibiting cell selectivity, high-salt resistance, and anti-biofilm properties. Amino Acids 2015; 48:505-22. [DOI: 10.1007/s00726-015-2104-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 09/22/2015] [Indexed: 12/13/2022]
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248
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Lipidic nanovesicles stabilize suspensions of metal oxide nanoparticles. Chem Phys Lipids 2015; 191:84-90. [DOI: 10.1016/j.chemphyslip.2015.08.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 08/17/2015] [Accepted: 08/18/2015] [Indexed: 11/18/2022]
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249
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Hinna A, Steiniger F, Hupfeld S, Stein P, Kuntsche J, Brandl M. Filter-extruded liposomes revisited: a study into size distributions and morphologies in relation to lipid-composition and process parameters. J Liposome Res 2015; 26:11-20. [PMID: 25826203 DOI: 10.3109/08982104.2015.1022556] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Filter-extrusion is a widely used technique for down-sizing of phospholipid vesicles. In order to gain a detailed insight into size and size distributions of filter-extruded vesicles composed of egg phosphatidyl-choline (with varying fractions of cholesterol)--in relation to extrusion-parameters (pore-size, number of filter passages, and flow-rate), flow field-flow fractionation in conjunction with multi-angle laser light scattering (AF4-MALLS, Wyatt Technology Corp., Santa Barbara, CA) was employed. Liposome size-distributions determined by AF4-MALLS were compared with those of dynamic light scattering and correlated with cryo-transmission electron microscopy and (31)P-NMR-analysis of lamellarity. Both the mean size of liposome and the width of size distribution were found to decrease with sequential extrusion through smaller pore size filters, starting at a size range of ≈70-415 nm upon repeated extrusion through 400 nm pore-filters, eventually ending with a size range from ≈30 to 85 nm upon extrusion through 30 nm pore size filters. While for small pores sizes (50 nm), increased flow rates resulted in smaller vesicles, no significant influence of flow rate on mean vesicle size was seen with larger pores. Cholesterol at increasing mol fractions up to 0.45 yielded bigger vesicles (at identical process conditions). For a cholesterol mol fraction of 0.5 in combination with small filter pore size, a bimodal size distribution was seen indicating cholesterol micro-crystallites. Finally, a protocol is suggested to prepare large (∼ 300 nm) liposomes with rather narrow size distribution, based on the filter extrusion at defined flow-rates in combination with freeze-/thaw-cycling and bench-top centrifugation.
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Affiliation(s)
- Askell Hinna
- a Department of Physics , Chemistry and Pharmacy, University of Southern Denmark , Campusvej , Odense , Denmark
| | - Frank Steiniger
- b Center for Electron Microscopy of the Medical Faculty, Friedrich Schiller University Jena , Ziegelmühlenweg , Jena , Germany , and
| | | | - Paul Stein
- a Department of Physics , Chemistry and Pharmacy, University of Southern Denmark , Campusvej , Odense , Denmark
| | - Judith Kuntsche
- a Department of Physics , Chemistry and Pharmacy, University of Southern Denmark , Campusvej , Odense , Denmark
| | - Martin Brandl
- a Department of Physics , Chemistry and Pharmacy, University of Southern Denmark , Campusvej , Odense , Denmark
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250
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Voinov MA, Smirnov AI. Ionizable Nitroxides for Studying Local Electrostatic Properties of Lipid Bilayers and Protein Systems by EPR. Methods Enzymol 2015; 564:191-217. [PMID: 26477252 PMCID: PMC5008871 DOI: 10.1016/bs.mie.2015.08.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Electrostatic interactions are known to play a major role in the myriad of biochemical and biophysical processes. Here, we describe biophysical methods to probe local electrostatic potentials of proteins and lipid bilayer systems that are based on an observation of reversible protonation of nitroxides by electron paramagnetic resonance (EPR). Two types of probes are described: (1) methanethiosulfonate derivatives of protonatable nitroxides for highly specific covalent modification of the cysteine's sulfhydryl groups and (2) spin-labeled phospholipids with a protonatable nitroxide tethered to the polar head group. The probes of both types report on their ionization state through changes in magnetic parameters and degree of rotational averaging, thus, allowing the electrostatic contribution to the interfacial pKa of the nitroxide, and, therefore, the local electrostatic potential to be determined. Due to their small molecular volume, these probes cause a minimal perturbation to the protein or lipid system. Covalent attachment secures the position of the reporter nitroxides. Experimental procedures to characterize and calibrate these probes by EPR, and also the methods to analyze the EPR spectra by simulations are outlined. The ionizable nitroxide labels and the nitroxide-labeled phospholipids described so far cover an exceptionally wide range of ca. 2.5-7.0 pH units, making them suitable to study a broad range of biophysical phenomena, especially at the negatively charged lipid bilayer surfaces. The rationale for selecting proper electrostatically neutral interface for probe calibration, and examples of lipid bilayer surface potential studies, are also described.
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Affiliation(s)
- Maxim A Voinov
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, USA
| | - Alex I Smirnov
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, USA.
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