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Lopez C, David-Briand E, Lollier V, Mériadec C, Bizien T, Pérez J, Artzner F. Solubilization of free β-sitosterol in milk sphingomyelin and polar lipid vesicles as carriers: Structural characterization of the membranes and sphingosome morphology. Food Res Int 2023; 165:112496. [PMID: 36869506 DOI: 10.1016/j.foodres.2023.112496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 11/29/2022] [Accepted: 01/20/2023] [Indexed: 02/05/2023]
Abstract
High consumption of plant sterols reduces the risk of cardiovascular diseases in humans and provides health benefits. Increasing the amount of plant sterols in the diet is therefore necessary to reach the recommended daily dietary intake. However, food supplementation with free plant sterols is challenging because of their low solubility in fats and water. The objectives of this study were to investigate the capacity of milk-sphingomyelin (milk-SM) and milk polar lipids to solubilise β-sitosterol molecules in bilayer membranes organised as vesicles called sphingosomes. The thermal and structural properties of milk-SM containing bilayers composed of various amounts of β-sitosterol were examined by differential scanning calorimetry (DSC) and temperature-controlled X-ray diffraction (XRD), the molecular interactions were studied using the Langmuir film technique, the morphologies of sphingosomes and β-sitosterol crystals were observed by microscopy. We showed that the milk-SM bilayers devoid of β-sitosterol exhibited a gel to fluid Lα phase transition for Tm = 34.5 °C and formed facetted spherical sphingosomes below Tm. The solubilisation of β-sitosterol within milk-SM bilayers induced a liquid-ordered Lo phaseabove 25 %mol (1.7 %wt) β-sitosterol and a softening of the membranes leading to the formation of elongated sphingosomes. Attractive molecular interactions revealed a condensing effect of β-sitosterol on milk-SM Langmuir monolayers. Above 40 %mol (25.7 %wt) β-sitosterol, partitioning occured with the formation of β-sitosterol microcrystals in the aqueous phase. Similar results were obtained with the solubilization of β-sitosterol within milk polar lipid vesicles. For the first time, this study highlighted the efficient solubilization of free β-sitosterol within milk-SM based vesicles, which opens new market opportunities for the formulation of functional foods enriched in non-crystalline free plant sterols.
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Affiliation(s)
- Christelle Lopez
- INRAE, BIA, F-44316 Nantes, France; INRAE, STLO, F-35000 Rennes, France.
| | | | - Virginie Lollier
- INRAE, BIA, F-44316 Nantes, France; INRAE, PROBE Research Infrastructure, BIBS Facility, F-44316 Nantes, France
| | | | - Thomas Bizien
- Synchrotron Soleil, L'Orme des Merisiers, Saint-Aubin BP48, F-91192 Gif-sur-Yvette, France
| | - Javier Pérez
- Synchrotron Soleil, L'Orme des Merisiers, Saint-Aubin BP48, F-91192 Gif-sur-Yvette, France
| | - Franck Artzner
- IPR, UMR 6251, CNRS, University of Rennes 1, F-35042 Rennes, France
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Lopez C, Mériadec C, David-Briand E, Dupont A, Bizien T, Artzner F, Riaublanc A, Anton M. Loading of lutein in egg-sphingomyelin vesicles as lipid carriers: Thermotropic phase behaviour, structure of sphingosome membranes and lutein crystals. Food Res Int 2020; 138:109770. [PMID: 33292950 DOI: 10.1016/j.foodres.2020.109770] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 07/30/2020] [Accepted: 09/30/2020] [Indexed: 10/23/2022]
Abstract
Lutein is a xanthophyll carotenoid provided exclusively by the diet, that has protective functions and beneficial effects on human health. Supplementation in lutein is necessary to reach the recommended daily dietary intake. However, the introduction of lutein into foods and beverages is a real challenge since this lipophilic nutrient has a poor aqueous solubility and a low bioavailability. In this study, we investigated the capacity of egg-sphingomyelin (ESM) vesicles called sphingosomes to solubilise lutein into the bilayers. The thermal and structural properties of ESM bilayers were examined in presence of various amounts of lutein by differential scanning calorimetry (DSC) and temperature-controlled X-ray diffraction (XRD), the structures of sphingosomes and lutein crystals were observed by microscopic techniques. ESM bilayers were in the fluid Lα phase above the phase transition temperature Tm = 39.6 °C and in the lamellar ripple Pβ' phase below Tm where ESM sphingosomes exhibited ondulations and were facetted. Lutein molecules were successfully incorporated into the ESM bilayers where they induced a structural disorganisation. For ESM/lutein 90/10 %mol (91.8/8.2 %wt; 89 mg lutein / g ESM), lutein partitioning occured with the formation of lutein crystals in the aqueous phase together with lutein-loaded ESM vesicles. This study highlighted the capacity of new lipid carriers such as egg-sphingosomes to solubilise lutein and opens perspectives for the formulation of effective lutein-fortified functionnal foods and beverages providing health benefits.
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Affiliation(s)
- Christelle Lopez
- INRAE, BIA, 44316 Nantes, France; INRAE, STLO, 35000 Rennes, France.
| | | | | | - Aurélien Dupont
- Univ Rennes, CNRS, Inserm, BIOSIT - UMS 3480, US_S 018, 35000 Rennes, France
| | - Thomas Bizien
- Synchrotron Soleil, L'Orme des Merisiers, Saint-Aubin BP48, 91192 Gif-sur-Yvette, France
| | - Franck Artzner
- IPR, UMR 6251, CNRS, University of Rennes 1, 35042 Rennes, France
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Abstract
Bioactive omega-3 polyunsaturated fatty acids have been shown to reduce the risk of death in patients with cardiovascular disease and alleviate the symptoms of other inflammatory diseases. However, the mechanisms of action of these effects remain unclear. It has been postulated that omega-3 polyunsaturated fatty acids modify cell membranes by incorporation into the membrane and altering the signaling properties of cellular receptors. In this chapter, we explore the effects of omega-3 polyunsaturated fatty acids on cell membrane structure and function. We present a review of the current evidence for the health benefits of these compounds and explore the molecular mechanisms through which omega-3 polyunsaturated fatty acids interact with membrane lipids and modulate bilayer structure. Using computational models of multicomponent phospholipid bilayers, we assess the consequences of incorporation of these fatty acids on membrane lipid packing, water permeation, and membrane structure.
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Affiliation(s)
- Manuela A A Ayee
- Department of Engineering, Dordt University, Sioux Center, IA, United States.
| | - Brendan C Bunker
- Department of Engineering, Dordt University, Sioux Center, IA, United States
| | - Jordan L De Groot
- Department of Engineering, Dordt University, Sioux Center, IA, United States
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Abstract
Integrins are bidirectional transmembrane receptors that play central roles in hemostasis and arterial thrombosis. They have been subject to structural studies for many years, in particular using X-ray crystallography, nuclear magnetic resonance spectroscopy, and two-dimensional negative stain electron microscopy. Despite considerable progress, a full consensus on the molecular mechanism of integrin activation is still lacking. Three-dimensional reconstructions of full-length human platelet integrin αIIbβ3 in lipid-bilayer nanodiscs obtained by electron cryo-microscopy and single-particle reconstruction have shed new light on the activation process. These studies show that integrin αIIbβ3 exists in a continuous conformational equilibrium ranging from a compact nodular conformation similar to that obtained in crystal structures to a fully extended state with the leg domains separated. This equilibrium is shifted towards the extended conformation when extracellular ligands, cytosolic activators and lipid-bilayer nanodiscs are added. Addition of cytosolic activators and extracellular ligands in the absense of nanodiscs produces significantly less dramatic shifts, emphasizing the importance of the membrane bilayer in the activation process.
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Affiliation(s)
- Dorit Hanein
- Bioinformatics and Structural Biology Program, Sanford-Burnham-Prebys Medical Discovery Institute, San Diego, CA, USA
| | - Niels Volkmann
- Bioinformatics and Structural Biology Program, Sanford-Burnham-Prebys Medical Discovery Institute, San Diego, CA, USA.
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Skotland T, Sandvig K, Llorente A. Lipids in exosomes: Current knowledge and the way forward. Prog Lipid Res 2017; 66:30-41. [PMID: 28342835 DOI: 10.1016/j.plipres.2017.03.001] [Citation(s) in RCA: 635] [Impact Index Per Article: 90.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 03/14/2017] [Accepted: 03/21/2017] [Indexed: 12/29/2022]
Abstract
Lipids are essential components of exosomal membranes, and it is well-known that specific lipids are enriched in exosomes compared to their parent cells. In this review we discuss current knowledge about the lipid composition of exosomes. We compare published data for different lipid classes in exosomes, and what is known about their lipid species, i.e. lipid molecules with different fatty acyl groups. Moreover, we elaborate on the hypothesis about hand-shaking between the very-long-chain sphingolipids in the outer leaflet and PS 18:0/18:1 in the inner leaflet, and we propose this to be an important mechanism in membrane biology, not only for exosomes. The similarity between the lipid composition of exosomes, HIV particles, and detergent resistant membranes, used as lipid rafts models, is also discussed. Furthermore, we summarize knowledge about the role of specific lipids and lipid metabolizing enzymes on the formation and release of exosomes. Finally, the use of exosomal lipids as biomarkers and how the lipid composition of exosomes may be of importance for researchers aiming to use exosomes as drug delivery vehicles is discussed. In conclusion, we have summarized what is presently known about lipids in exosomes and identified issues that should be taken into consideration in future studies.
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Affiliation(s)
- Tore Skotland
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital-The Norwegian Radium Hospital, 0379 Oslo, Norway; Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, 0379 Oslo, Norway.
| | - Kirsten Sandvig
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital-The Norwegian Radium Hospital, 0379 Oslo, Norway; Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, 0379 Oslo, Norway; Department of Molecular Biosciences, University of Oslo, 0316 Oslo, Norway
| | - Alicia Llorente
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital-The Norwegian Radium Hospital, 0379 Oslo, Norway; Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, 0379 Oslo, Norway
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Petit VW, Rolland JL, Blond A, Cazevieille C, Djediat C, Peduzzi J, Goulard C, Bachère E, Dupont J, Destoumieux-Garzón D, Rebuffat S. A hemocyanin-derived antimicrobial peptide from the penaeid shrimp adopts an alpha-helical structure that specifically permeabilizes fungal membranes. Biochim Biophys Acta Gen Subj 2015; 1860:557-68. [PMID: 26708991 DOI: 10.1016/j.bbagen.2015.12.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 11/27/2015] [Accepted: 12/16/2015] [Indexed: 10/22/2022]
Abstract
BACKGROUND Hemocyanins are respiratory proteins with multiple functions. In diverse crustaceans hemocyanins can release histidine-rich antimicrobial peptides in response to microbial challenge. In penaeid shrimp, strictly antifungal peptides are released from the C-terminus of hemocyanins. METHODS The three-dimensional structure of the antifungal peptide PvHCt from Litopenaeus vannamei was determined by NMR. Its mechanism of action against the shrimp pathogen Fusarium oxysporum was investigated using immunochemistry, fluorescence and transmission electron microscopy. RESULTS PvHCt folded into an amphipathic α-helix in membrane-mimicking media and displayed a random conformation in aqueous environment. In contact with F. oxysporum, PvHCt bound massively to the surface of fungal hyphae without being imported into the cytoplasm. At minimal inhibitory concentrations, PvHCt made the fungal membrane permeable to SYTOX-green and fluorescent dextran beads of 4 kDa. Higher size beads could not enter the cytoplasm. Therefore, PvHCt likely creates local damages to the fungal membrane. While the fungal cell wall appeared preserved, gradual degeneration of the cytoplasm most often resulting in cell lysis was observed in fungal spores and hyphae. In the remaining fungal cells, PvHCt induced a protective response by the formation of daughter hyphae. CONCLUSION The massive accumulation of PvHCt at the surface of fungal hyphae and subsequent insertion into the plasma membrane disrupt its integrity as a permeability barrier, leading to disruption of internal homeostasis and fungal death. GENERAL SIGNIFICANCE The histidine-rich antimicrobial peptide PvHCt derived from shrimp hemocyanin is a strictly antifungal peptide, which adopts an amphipathic α-helical structure, and selectively binds to and permeabilizes fungal cells.
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Affiliation(s)
- Vanessa W Petit
- Laboratory Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Muséum national d'Histoire naturelle (MNHN), Centre national de la Recherche scientifique (CNRS), Sorbonne Universités, 75005 Paris, France
| | - Jean-Luc Rolland
- Interactions Hôtes-Pathogènes-Environnements (IHPE), Ifremer, CNRS, UPVD, Université de Montpellier, UMR 5244, 34090 Montpellier, France
| | - Alain Blond
- Laboratory Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Muséum national d'Histoire naturelle (MNHN), Centre national de la Recherche scientifique (CNRS), Sorbonne Universités, 75005 Paris, France
| | - Chantal Cazevieille
- COMET, Plateau de microscopie électronique, Plateforme Montpellier RIO Imaging, 34091 Montpellier, France
| | - Chakib Djediat
- Laboratory Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Muséum national d'Histoire naturelle (MNHN), Centre national de la Recherche scientifique (CNRS), Sorbonne Universités, 75005 Paris, France
| | - Jean Peduzzi
- Laboratory Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Muséum national d'Histoire naturelle (MNHN), Centre national de la Recherche scientifique (CNRS), Sorbonne Universités, 75005 Paris, France
| | - Christophe Goulard
- Laboratory Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Muséum national d'Histoire naturelle (MNHN), Centre national de la Recherche scientifique (CNRS), Sorbonne Universités, 75005 Paris, France
| | - Evelyne Bachère
- Interactions Hôtes-Pathogènes-Environnements (IHPE), Ifremer, CNRS, UPVD, Université de Montpellier, UMR 5244, 34090 Montpellier, France
| | - Joëlle Dupont
- Institut de Systématique, Evolution, Biodiversité (ISYEB, UMR 7205), MNHN, Université Pierre et Marie Curie (UPMC), CNRS, Sorbonne Universités, 75005 Paris, France
| | - Delphine Destoumieux-Garzón
- Interactions Hôtes-Pathogènes-Environnements (IHPE), Ifremer, CNRS, UPVD, Université de Montpellier, UMR 5244, 34090 Montpellier, France
| | - Sylvie Rebuffat
- Laboratory Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Muséum national d'Histoire naturelle (MNHN), Centre national de la Recherche scientifique (CNRS), Sorbonne Universités, 75005 Paris, France.
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Cebrián R, Martínez-Bueno M, Valdivia E, Albert A, Maqueda M, Sánchez-Barrena MJ. The bacteriocin AS-48 requires dimer dissociation followed by hydrophobic interactions with the membrane for antibacterial activity. J Struct Biol 2015; 190:162-72. [PMID: 25816760 DOI: 10.1016/j.jsb.2015.03.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 03/04/2015] [Accepted: 03/18/2015] [Indexed: 01/15/2023]
Abstract
The molecular mechanism underlining the antibacterial activity of the bacteriocin AS-48 is not known, and two different and opposite alternatives have been proposed. Available data suggested that the interaction of positively charged amino acids of AS-48 with the membrane would produce membrane destabilization and disruption. Alternatively, it has been proposed that AS-48 activity could rely on the effective insertion of the bacteriocin into the membrane. The biological and structural properties of the AS-48G13K/L40K double mutant were investigated to shed light on this subject. Compared with the wild type, the mutant protein suffered an important reduction in the antibacterial activity. Biochemical and structural studies of AS-48G13K/L40K mutant suggest the basis of its decreased antimicrobial activity. Lipid cosedimentation assays showed that the membrane affinity of AS-48G13K/L40K is 12-fold lower than that observed for the wild type. L40K mutation is responsible for this reduced membrane affinity and thus, hydrophobic interactions are involved in membrane association. Furthermore, the high-resolution crystal structure of AS-48G13K/L40K, together with the study of its dimeric character in solution showed that G13K stabilizes the inactive water-soluble dimer, which displays a reduced dipole moment. Our data suggest that the cumulative effect of these three affected properties reduces AS-48 activity, and point out that the bactericidal effect is achieved by the electrostatically driven approach of the inactive water-soluble dimer towards the membrane, followed by the dissociation and insertion of the protein into the lipid bilayer.
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Affiliation(s)
- Rubén Cebrián
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Spain
| | | | - Eva Valdivia
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Spain
| | - Armando Albert
- Departamento de Cristalografía y Biología Estructural, Instituto de Química Física "Rocasolano", Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Mercedes Maqueda
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Spain
| | - María José Sánchez-Barrena
- Departamento de Cristalografía y Biología Estructural, Instituto de Química Física "Rocasolano", Consejo Superior de Investigaciones Científicas, Madrid, Spain.
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