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Mesén-Porras S, Rojas-Céspedes A, Molina-Mora JA, Vega-Baudrit J, Siles F, Quiros S, Mora-Rodríguez R. Sphingolipid-Based Synergistic Interactions to Enhance Chemosensitivity in Lung Cancer Cells. Cells 2023; 12:2588. [PMID: 37998323 PMCID: PMC10670127 DOI: 10.3390/cells12222588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/13/2023] [Accepted: 10/25/2023] [Indexed: 11/25/2023] Open
Abstract
Tumor heterogeneity leads to drug resistance in cancer treatment with the crucial role of sphingolipids in cell fate and stress signaling. We analyzed sphingolipid metabolism and autophagic flux to study chemotherapeutic interactions on the A549 lung cancer model. Loaded cells with fluorescent sphingomyelin analog (BODIPY) and mCherry-EGFP-LC3B were used to track autophagic flux and assess cytotoxicity when cells are exposed to chemotherapy (epirubicin, cisplatin, and paclitaxel) together with sphingolipid pathway inhibitors and autophagy modulators. Our cell model approach employed fluorescent sphingolipid biosensors and a Gaussian Mixture Model of cell heterogeneity profiles to map the influence of chemotherapy on the sphingolipid pathway and infer potential synergistic interactions. Results showed significant synergy, especially when combining epirubicin with autophagy inducers (rapamycin and Torin), reducing cell viability. Cisplatin also synergized with a ceramidase inhibitor. However, paclitaxel often led to antagonistic effects. Our mapping model suggests that combining chemotherapies with autophagy inducers increases vesicle formation, possibly linked to ceramide accumulation, triggering cell death. However, the in silico model proposed ceramide accumulation in autophagosomes, and kinetic analysis provided evidence of sphingolipid colocalization in autophagosomes. Further research is needed to identify specific sphingolipids accumulating in autophagosomes. These findings offer insights into potential strategies for overcoming chemotherapy resistance by targeting the sphingolipid pathway.
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Affiliation(s)
- Susana Mesén-Porras
- Research Center on Tropical Diseases (CIET), Faculty of Microbiology, University of Costa Rica, San José 11501-2060, Costa Rica; (S.M.-P.); (A.R.-C.); (J.A.M.-M.); (S.Q.)
- Research Center on Surgery and Cancer (CICICA), Campus Rodrigo Facio, University of Costa Rica, San José 11501-2060, Costa Rica;
- Master Program in Microbiology, University of Costa Rica, San José 11501-2060, Costa Rica
- National Laboratory of Nanotechnology (LANOTEC), National Center of High Technology (CeNAT), Pavas, San José 1174-1200, Costa Rica;
| | - Andrea Rojas-Céspedes
- Research Center on Tropical Diseases (CIET), Faculty of Microbiology, University of Costa Rica, San José 11501-2060, Costa Rica; (S.M.-P.); (A.R.-C.); (J.A.M.-M.); (S.Q.)
| | - José Arturo Molina-Mora
- Research Center on Tropical Diseases (CIET), Faculty of Microbiology, University of Costa Rica, San José 11501-2060, Costa Rica; (S.M.-P.); (A.R.-C.); (J.A.M.-M.); (S.Q.)
| | - José Vega-Baudrit
- National Laboratory of Nanotechnology (LANOTEC), National Center of High Technology (CeNAT), Pavas, San José 1174-1200, Costa Rica;
| | - Francisco Siles
- Research Center on Surgery and Cancer (CICICA), Campus Rodrigo Facio, University of Costa Rica, San José 11501-2060, Costa Rica;
- Pattern Recognition and Intelligent Systems Laboratory (PRIS-Lab), Department and Postgraduate Studies in Electrical Engineering, University of Costa Rica, San José 11501-2060, Costa Rica
| | - Steve Quiros
- Research Center on Tropical Diseases (CIET), Faculty of Microbiology, University of Costa Rica, San José 11501-2060, Costa Rica; (S.M.-P.); (A.R.-C.); (J.A.M.-M.); (S.Q.)
- Research Center on Surgery and Cancer (CICICA), Campus Rodrigo Facio, University of Costa Rica, San José 11501-2060, Costa Rica;
| | - Rodrigo Mora-Rodríguez
- Research Center on Tropical Diseases (CIET), Faculty of Microbiology, University of Costa Rica, San José 11501-2060, Costa Rica; (S.M.-P.); (A.R.-C.); (J.A.M.-M.); (S.Q.)
- Research Center on Surgery and Cancer (CICICA), Campus Rodrigo Facio, University of Costa Rica, San José 11501-2060, Costa Rica;
- Master Program in Microbiology, University of Costa Rica, San José 11501-2060, Costa Rica
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2
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Ghodsi M, Cloos AS, Mozaheb N, Van Der Smissen P, Henriet P, Pierreux CE, Cellier N, Mingeot-Leclercq MP, Najdovski T, Tyteca D. Variability of extracellular vesicle release during storage of red blood cell concentrates is associated with differential membrane alterations, including loss of cholesterol-enriched domains. Front Physiol 2023; 14:1205493. [PMID: 37408586 PMCID: PMC10318158 DOI: 10.3389/fphys.2023.1205493] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 05/30/2023] [Indexed: 07/07/2023] Open
Abstract
Transfusion of red blood cell concentrates is the most common medical procedure to treat anaemia. However, their storage is associated with development of storage lesions, including the release of extracellular vesicles. These vesicles affect in vivo viability and functionality of transfused red blood cells and appear responsible for adverse post-transfusional complications. However, the biogenesis and release mechanisms are not fully understood. We here addressed this issue by comparing the kinetics and extents of extracellular vesicle release as well as red blood cell metabolic, oxidative and membrane alterations upon storage in 38 concentrates. We showed that extracellular vesicle abundance increased exponentially during storage. The 38 concentrates contained on average 7 × 1012 extracellular vesicles at 6 weeks (w) but displayed a ∼40-fold variability. These concentrates were subsequently classified into 3 cohorts based on their vesiculation rate. The variability in extracellular vesicle release was not associated with a differential red blood cell ATP content or with increased oxidative stress (in the form of reactive oxygen species, methaemoglobin and band3 integrity) but rather with red blood cell membrane modifications, i.e., cytoskeleton membrane occupancy, lateral heterogeneity in lipid domains and transversal asymmetry. Indeed, no changes were noticed in the low vesiculation group until 6w while the medium and the high vesiculation groups exhibited a decrease in spectrin membrane occupancy between 3 and 6w and an increase of sphingomyelin-enriched domain abundance from 5w and of phosphatidylserine surface exposure from 8w. Moreover, each vesiculation group showed a decrease of cholesterol-enriched domains associated with a cholesterol content increase in extracellular vesicles but at different storage time points. This observation suggested that cholesterol-enriched domains could represent a starting point for vesiculation. Altogether, our data reveal for the first time that the differential extent of extracellular vesicle release in red blood cell concentrates did not simply result from preparation method, storage conditions or technical issues but was linked to membrane alterations.
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Affiliation(s)
- Marine Ghodsi
- Cell Biology Unit and Platform for Imaging Cells and Tissues, de Duve Institute, UCLouvain, Brussels, Belgium
| | - Anne-Sophie Cloos
- Cell Biology Unit and Platform for Imaging Cells and Tissues, de Duve Institute, UCLouvain, Brussels, Belgium
| | - Negar Mozaheb
- Cellular and Molecular Pharmacology Unit, Louvain Drug Research Institute, UCLouvain, Brussels, Belgium
| | - Patrick Van Der Smissen
- Cell Biology Unit and Platform for Imaging Cells and Tissues, de Duve Institute, UCLouvain, Brussels, Belgium
| | - Patrick Henriet
- Cell Biology Unit and Platform for Imaging Cells and Tissues, de Duve Institute, UCLouvain, Brussels, Belgium
| | - Christophe E. Pierreux
- Cell Biology Unit and Platform for Imaging Cells and Tissues, de Duve Institute, UCLouvain, Brussels, Belgium
| | | | | | - Tomé Najdovski
- Service du Sang, Croix-Rouge de Belgique, Suarlée, Belgium
| | - Donatienne Tyteca
- Cell Biology Unit and Platform for Imaging Cells and Tissues, de Duve Institute, UCLouvain, Brussels, Belgium
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Cholesterol and Sphingomyelin Polarize at the Leading Edge of Migrating Myoblasts and Involve Their Clustering in Submicrometric Domains. Biomolecules 2023; 13:biom13020319. [PMID: 36830688 PMCID: PMC9953279 DOI: 10.3390/biom13020319] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 01/26/2023] [Accepted: 02/02/2023] [Indexed: 02/11/2023] Open
Abstract
Myoblast migration is crucial for myogenesis and muscular tissue homeostasis. However, its spatiotemporal control remains elusive. Here, we explored the involvement of plasma membrane cholesterol and sphingolipids in this process. In resting C2C12 mouse myoblasts, those lipids clustered in sphingomyelin/cholesterol/GM1 ganglioside (SM/chol/GM1)- and cholesterol (chol)-enriched domains, which presented a lower stiffness than the bulk membrane. Upon migration, cholesterol and sphingomyelin polarized at the front, forming cholesterol (chol)- and sphingomyelin/cholesterol (SM/chol)-enriched domains, while GM1-enriched domains polarized at the rear. A comparison of domain proportion suggested that SM/chol- and GM1-enriched domains originated from the SM/chol/GM1-coenriched domains found at resting state. Modulation of domain proportion (through cholesterol depletion, combined or not with actin polymerization inhibition, or sphingolipid synthesis inhibition) revealed that the higher the chol- and SM/chol-enriched domains, the higher the myoblast migration. At the front, chol- and SM/chol-enriched domains were found in proximity with F-actin fibers and the lateral mobility of sphingomyelin in domains was specifically restricted in a cholesterol- and cytoskeleton-dependent manner while domain abrogation impaired F-actin and focal adhesion polarization. Altogether, we showed the polarization of cholesterol and sphingomyelin and their clustering in chol- and SM/chol-enriched domains with differential properties and roles, providing a mechanism for the spatial and functional control of myoblast migration.
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Maja M, Tyteca D. Alteration of cholesterol distribution at the plasma membrane of cancer cells: From evidence to pathophysiological implication and promising therapy strategy. Front Physiol 2022; 13:999883. [PMID: 36439249 PMCID: PMC9682260 DOI: 10.3389/fphys.2022.999883] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 10/10/2022] [Indexed: 11/11/2022] Open
Abstract
Cholesterol-enriched domains are nowadays proposed to contribute to cancer cell proliferation, survival, death and invasion, with important implications in tumor progression. They could therefore represent promising targets for new anticancer treatment. However, although diverse strategies have been developed over the years from directly targeting cholesterol membrane content/distribution to adjusting sterol intake, all approaches present more or less substantial limitations. Those data emphasize the need to optimize current strategies, to develop new specific cholesterol-targeting anticancer drugs and/or to combine them with additional strategies targeting other lipids than cholesterol. Those objectives can only be achieved if we first decipher (i) the mechanisms that govern the formation and deformation of the different types of cholesterol-enriched domains and their interplay in healthy cells; (ii) the mechanisms behind domain deregulation in cancer; (iii) the potential generalization of observations in different types of cancer; and (iv) the specificity of some alterations in cancer vs. non-cancer cells as promising strategy for anticancer therapy. In this review, we will discuss the current knowledge on the homeostasis, roles and membrane distribution of cholesterol in non-tumorigenic cells. We will then integrate documented alterations of cholesterol distribution in domains at the surface of cancer cells and the mechanisms behind their contribution in cancer processes. We shall finally provide an overview on the potential strategies developed to target those cholesterol-enriched domains in cancer therapy.
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Cloos AS, Daenen LGM, Maja M, Stommen A, Vanderroost J, Van Der Smissen P, Rab M, Westerink J, Mignolet E, Larondelle Y, Terrasi R, Muccioli GG, Dumitru AC, Alsteens D, van Wijk R, Tyteca D. Impaired Cytoskeletal and Membrane Biophysical Properties of Acanthocytes in Hypobetalipoproteinemia - A Case Study. Front Physiol 2021; 12:638027. [PMID: 33708142 PMCID: PMC7940373 DOI: 10.3389/fphys.2021.638027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 01/25/2021] [Indexed: 12/03/2022] Open
Abstract
Familial hypobetalipoproteinemia is a metabolic disorder mainly caused by mutations in the apolipoprotein B gene. In its homozygous form it can lead without treatment to severe ophthalmological and neurological manifestations. In contrast, the heterozygous form is generally asymptomatic but associated with a low risk of cardiovascular disease. Acanthocytes or thorny red blood cells (RBCs) are described for both forms of the disease. However, those morphological changes are poorly characterized and their potential consequences for RBC functionality are not understood. Thus, in the present study, we asked whether, to what extent and how acanthocytes from a patient with heterozygous familial hypobetalipoproteinemia could exhibit altered RBC functionality. Acanthocytes represented 50% of the total RBC population and contained mitoTracker-positive surface patches, indicating the presence of mitochondrial fragments. While RBC osmotic fragility, calcium content and ATP homeostasis were preserved, a slight decrease of RBC deformability combined with an increase of intracellular free reactive oxygen species were observed. The spectrin cytoskeleton was altered, showing a lower density and an enrichment in patches. At the membrane level, no obvious modification of the RBC membrane fatty acids nor of the cholesterol content were detected but the ceramide species were all increased. Membrane stiffness and curvature were also increased whereas transversal asymmetry was preserved. In contrast, lateral asymmetry was highly impaired showing: (i) increased abundance and decreased functionality of sphingomyelin-enriched domains; (ii) cholesterol enrichment in spicules; and (iii) ceramide enrichment in patches. We propose that oxidative stress induces cytoskeletal alterations, leading to increased membrane stiffness and curvature and impaired lipid lateral distribution in domains and spicules. In addition, ceramide- and spectrin-enriched patches could result from a RBC maturation defect. Altogether, the data indicate that acanthocytes are associated with cytoskeletal and membrane lipid lateral asymmetry alterations, while deformability is only mildly impaired. In addition, familial hypobetalipoproteinemia might also affect RBC precursors leading to disturbed RBC maturation. This study paves the way for the potential use of membrane biophysics and lipid vital imaging as new methods for diagnosis of RBC disorders.
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Affiliation(s)
- Anne-Sophie Cloos
- CELL Unit & PICT Imaging Platform, de Duve Institute, UCLouvain, Brussels, Belgium
| | - Laura G M Daenen
- Department of Hematology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Mauriane Maja
- CELL Unit & PICT Imaging Platform, de Duve Institute, UCLouvain, Brussels, Belgium
| | - Amaury Stommen
- CELL Unit & PICT Imaging Platform, de Duve Institute, UCLouvain, Brussels, Belgium
| | - Juliette Vanderroost
- CELL Unit & PICT Imaging Platform, de Duve Institute, UCLouvain, Brussels, Belgium
| | | | - Minke Rab
- Central Diagnostic Laboratory - Research, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Jan Westerink
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Eric Mignolet
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Ottignies-Louvain-la-Neuve, Belgium
| | - Yvan Larondelle
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Ottignies-Louvain-la-Neuve, Belgium
| | - Romano Terrasi
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, UCLouvain, Brussels, Belgium
| | - Giulio G Muccioli
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, UCLouvain, Brussels, Belgium
| | - Andra C Dumitru
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Ottignies-Louvain-la-Neuve, Belgium
| | - David Alsteens
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Ottignies-Louvain-la-Neuve, Belgium
| | - Richard van Wijk
- Central Diagnostic Laboratory - Research, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Donatienne Tyteca
- CELL Unit & PICT Imaging Platform, de Duve Institute, UCLouvain, Brussels, Belgium
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6
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Haynes AZ, Levine M. Detection of Human Growth Hormone (hGH) via Cyclodextrin-Promoted Fluorescence Modulation. ANAL LETT 2020. [DOI: 10.1080/00032719.2020.1828445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Anna Z. Haynes
- Department of Chemistry, University of Rhode Island, Kingston, RI, USA
| | - Mindy Levine
- Department of Chemical Sciences, Ariel University, Ariel, Israel
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Melzak KA, Moreno-Flores S, Bieback K. Spicule movement on RBCs during echinocyte formation and possible segregation in the RBC membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183338. [PMID: 32485161 DOI: 10.1016/j.bbamem.2020.183338] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 04/27/2020] [Accepted: 04/28/2020] [Indexed: 11/30/2022]
Abstract
We use phase contrast microscopy of red blood cells to observe the transition between the initial discocyte shape and a spiculated echinocyte form. During the early stages of this change, spicules can move across the surface of the cell; individual spicules can also split apart into pairs. One possible explanation of this behaviour is that the membrane forms large scale domains in association with the spicules. The spicules are formed initially at the rim of the cell and then move at speeds of up to 3 μm/min towards the centre of the disc. Spicule formation that was reversed and then allowed to proceed a second time resulted in spicules at reproducible places, a shape memory effect that implies that the cytoskeleton contributes towards stopping the spicule movement. The splitting of the spicules produces a well-defined shape change with an increase in membrane curvature associated with formation of the daughter pair of spicules; the total boundary length around the spicules also increases. Following the model in which the spicules are associated with lipid domains, these observations suggest an experimental procedure that could potentially be applied to the calculation of the line tension of lipid domains in living cells.
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Affiliation(s)
- K A Melzak
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany.
| | | | - K Bieback
- Institute for Transfusion Medicine and Immunology, Flowcore Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
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8
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Pollet H, Cloos AS, Stommen A, Vanderroost J, Conrard L, Paquot A, Ghodsi M, Carquin M, Léonard C, Guthmann M, Lingurski M, Vermylen C, Killian T, Gatto L, Rider M, Pyr dit Ruys S, Vertommen D, Vikkula M, Brouillard P, Van Der Smissen P, Muccioli GG, Tyteca D. Aberrant Membrane Composition and Biophysical Properties Impair Erythrocyte Morphology and Functionality in Elliptocytosis. Biomolecules 2020; 10:biom10081120. [PMID: 32751168 PMCID: PMC7465299 DOI: 10.3390/biom10081120] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/20/2020] [Accepted: 07/22/2020] [Indexed: 12/17/2022] Open
Abstract
Red blood cell (RBC) deformability is altered in inherited RBC disorders but the mechanism behind this is poorly understood. Here, we explored the molecular, biophysical, morphological, and functional consequences of α-spectrin mutations in a patient with hereditary elliptocytosis (pEl) almost exclusively expressing the Pro260 variant of SPTA1 and her mother (pElm), heterozygous for this mutation. At the molecular level, the pEI RBC proteome was globally preserved but spectrin density at cell edges was increased. Decreased phosphatidylserine vs. increased lysophosphatidylserine species, and enhanced lipid peroxidation, methemoglobin, and plasma acid sphingomyelinase (aSMase) activity were observed. At the biophysical level, although membrane transversal asymmetry was preserved, curvature at RBC edges and rigidity were increased. Lipid domains were altered for membrane:cytoskeleton anchorage, cholesterol content and response to Ca2+ exchange stimulation. At the morphological and functional levels, pEl RBCs exhibited reduced size and circularity, increased fragility and impaired membrane Ca2+ exchanges. The contribution of increased membrane curvature to the pEl phenotype was shown by mechanistic experiments in healthy RBCs upon lysophosphatidylserine membrane insertion. The role of lipid domain defects was proved by cholesterol depletion and aSMase inhibition in pEl. The data indicate that aberrant membrane content and biophysical properties alter pEl RBC morphology and functionality.
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Affiliation(s)
- Hélène Pollet
- CELL Unit & PICT Imaging Platform, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (H.P.); (A.-S.C.); (A.S.); (J.V.); (L.C.); (M.G.); (M.C.); (C.L.); (M.G.); (M.L.); (P.V.D.S.)
| | - Anne-Sophie Cloos
- CELL Unit & PICT Imaging Platform, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (H.P.); (A.-S.C.); (A.S.); (J.V.); (L.C.); (M.G.); (M.C.); (C.L.); (M.G.); (M.L.); (P.V.D.S.)
| | - Amaury Stommen
- CELL Unit & PICT Imaging Platform, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (H.P.); (A.-S.C.); (A.S.); (J.V.); (L.C.); (M.G.); (M.C.); (C.L.); (M.G.); (M.L.); (P.V.D.S.)
| | - Juliette Vanderroost
- CELL Unit & PICT Imaging Platform, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (H.P.); (A.-S.C.); (A.S.); (J.V.); (L.C.); (M.G.); (M.C.); (C.L.); (M.G.); (M.L.); (P.V.D.S.)
| | - Louise Conrard
- CELL Unit & PICT Imaging Platform, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (H.P.); (A.-S.C.); (A.S.); (J.V.); (L.C.); (M.G.); (M.C.); (C.L.); (M.G.); (M.L.); (P.V.D.S.)
| | - Adrien Paquot
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, UCLouvain, 1200 Brussels, Belgium; (A.P.); (G.G.M.)
| | - Marine Ghodsi
- CELL Unit & PICT Imaging Platform, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (H.P.); (A.-S.C.); (A.S.); (J.V.); (L.C.); (M.G.); (M.C.); (C.L.); (M.G.); (M.L.); (P.V.D.S.)
| | - Mélanie Carquin
- CELL Unit & PICT Imaging Platform, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (H.P.); (A.-S.C.); (A.S.); (J.V.); (L.C.); (M.G.); (M.C.); (C.L.); (M.G.); (M.L.); (P.V.D.S.)
| | - Catherine Léonard
- CELL Unit & PICT Imaging Platform, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (H.P.); (A.-S.C.); (A.S.); (J.V.); (L.C.); (M.G.); (M.C.); (C.L.); (M.G.); (M.L.); (P.V.D.S.)
| | - Manuel Guthmann
- CELL Unit & PICT Imaging Platform, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (H.P.); (A.-S.C.); (A.S.); (J.V.); (L.C.); (M.G.); (M.C.); (C.L.); (M.G.); (M.L.); (P.V.D.S.)
| | - Maxime Lingurski
- CELL Unit & PICT Imaging Platform, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (H.P.); (A.-S.C.); (A.S.); (J.V.); (L.C.); (M.G.); (M.C.); (C.L.); (M.G.); (M.L.); (P.V.D.S.)
| | - Christiane Vermylen
- PEDI Unit, Institut de Recherche Expérimentale et Clinique & Saint-Luc Hospital, UCLouvain, 1200 Brussels, Belgium;
| | - Theodore Killian
- Computational Biology and Bioinformatics Unit, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (T.K.); (L.G.)
| | - Laurent Gatto
- Computational Biology and Bioinformatics Unit, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (T.K.); (L.G.)
| | - Mark Rider
- PHOS Unit & MASSPROT Proteomics Platform, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (M.R.); (S.P.d.R.); (D.V.)
| | - Sébastien Pyr dit Ruys
- PHOS Unit & MASSPROT Proteomics Platform, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (M.R.); (S.P.d.R.); (D.V.)
| | - Didier Vertommen
- PHOS Unit & MASSPROT Proteomics Platform, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (M.R.); (S.P.d.R.); (D.V.)
| | - Miikka Vikkula
- Human Molecular Genetics, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (M.V.); (P.B.)
- Walloon Excellence in Life Sciences and Biotechnology (WELBIO), de Duve Institute, UCLouvain, 1200 Brussels, Belgium
| | - Pascal Brouillard
- Human Molecular Genetics, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (M.V.); (P.B.)
| | - Patrick Van Der Smissen
- CELL Unit & PICT Imaging Platform, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (H.P.); (A.-S.C.); (A.S.); (J.V.); (L.C.); (M.G.); (M.C.); (C.L.); (M.G.); (M.L.); (P.V.D.S.)
| | - Giulio G. Muccioli
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, UCLouvain, 1200 Brussels, Belgium; (A.P.); (G.G.M.)
| | - Donatienne Tyteca
- CELL Unit & PICT Imaging Platform, de Duve Institute, UCLouvain, 1200 Brussels, Belgium; (H.P.); (A.-S.C.); (A.S.); (J.V.); (L.C.); (M.G.); (M.C.); (C.L.); (M.G.); (M.L.); (P.V.D.S.)
- Correspondence:
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9
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Cloos AS, Ghodsi M, Stommen A, Vanderroost J, Dauguet N, Pollet H, D'Auria L, Mignolet E, Larondelle Y, Terrasi R, Muccioli GG, Van Der Smissen P, Tyteca D. Interplay Between Plasma Membrane Lipid Alteration, Oxidative Stress and Calcium-Based Mechanism for Extracellular Vesicle Biogenesis From Erythrocytes During Blood Storage. Front Physiol 2020; 11:712. [PMID: 32719614 PMCID: PMC7350142 DOI: 10.3389/fphys.2020.00712] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/29/2020] [Indexed: 12/18/2022] Open
Abstract
The shedding of extracellular vesicles (EVs) from the red blood cell (RBC) surface is observed during senescence in vivo and RBC storage in vitro. Two main models for EV shedding, respectively based on calcium rise and oxidative stress, have been proposed in the literature but the role of the plasma membrane lipid composition and properties is not understood. Using blood in K+/EDTA tubes stored for up to 4 weeks at 4°C as a relevant RBC vesiculation model, we showed here that the RBC plasma membrane lipid composition, organization in domains and biophysical properties were progressively modified during storage and contributed to the RBC vesiculation. First, the membrane content in cholesterol and linoleic acid decreased whereas lipid peroxidation and spectrin:membrane occupancy increased, all compatible with higher membrane rigidity. Second, phosphatidylserine surface exposure showed a first rapid rise due to membrane cholesterol decrease, followed by a second calcium-dependent increase. Third, lipid domains mainly enriched in GM1 or sphingomyelin strongly increased from the 1st week while those mainly enriched in cholesterol or ceramide decreased during the 1st and 4th week, respectively. Fourth, the plasmatic acid sphingomyelinase activity considerably increased upon storage following the sphingomyelin-enriched domain rise and potentially inducing the loss of ceramide-enriched domains. Fifth, in support of the shedding of cholesterol- and ceramide-enriched domains from the RBC surface, the number of cholesterol-enriched domains lost and the abundance of EVs released during the 1st week perfectly matched. Moreover, RBC-derived EVs were enriched in ceramide at the 4th week but depleted in sphingomyelin. Then, using K+/EDTA tubes supplemented with glucose to longer preserve the ATP content, we better defined the sequence of events. Altogether, we showed that EV shedding from lipid domains only represents part of the global vesiculation mechanistics, for which we propose four successive events (cholesterol domain decrease, oxidative stress, sphingomyelin/sphingomyelinase/ceramide/calcium alteration and phosphatidylserine exposure).
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Affiliation(s)
- Anne-Sophie Cloos
- CELL Unit and PICT Platform, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Marine Ghodsi
- CELL Unit and PICT Platform, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Amaury Stommen
- CELL Unit and PICT Platform, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Juliette Vanderroost
- CELL Unit and PICT Platform, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Nicolas Dauguet
- GECE Unit and CYTF Platform, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Hélène Pollet
- CELL Unit and PICT Platform, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Ludovic D'Auria
- NCHM Unit, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Eric Mignolet
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Yvan Larondelle
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Romano Terrasi
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Giulio G Muccioli
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Patrick Van Der Smissen
- CELL Unit and PICT Platform, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Donatienne Tyteca
- CELL Unit and PICT Platform, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
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10
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Gorman BL, Kraft ML. High-Resolution Secondary Ion Mass Spectrometry Analysis of Cell Membranes. Anal Chem 2020; 92:1645-1652. [PMID: 31854976 DOI: 10.1021/acs.analchem.9b04492] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
This Feature describes the use a Cameca NanoSIMS instrument for directly imaging specific lipid and protein species in the plasma membranes of mammalian cells with approximately 100 nm-lateral resolution and discusses how these analyses have already begun to transform fundamental concepts in the field of membrane biology. Secondary ion generation is discussed with emphasis on the constraints that affect the detection and identification of membrane components, and then the sample preparation methodologies and data analysis strategies that address these constraints are described.
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11
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Conrard L, Tyteca D. Regulation of Membrane Calcium Transport Proteins by the Surrounding Lipid Environment. Biomolecules 2019; 9:E513. [PMID: 31547139 PMCID: PMC6843150 DOI: 10.3390/biom9100513] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/09/2019] [Accepted: 09/10/2019] [Indexed: 12/11/2022] Open
Abstract
Calcium ions (Ca2+) are major messengers in cell signaling, impacting nearly every aspect of cellular life. Those signals are generated within a wide spatial and temporal range through a large variety of Ca2+ channels, pumps, and exchangers. More and more evidences suggest that Ca2+ exchanges are regulated by their surrounding lipid environment. In this review, we point out the technical challenges that are currently being overcome and those that still need to be defeated to analyze the Ca2+ transport protein-lipid interactions. We then provide evidences for the modulation of Ca2+ transport proteins by lipids, including cholesterol, acidic phospholipids, sphingolipids, and their metabolites. We also integrate documented mechanisms involved in the regulation of Ca2+ transport proteins by the lipid environment. Those include: (i) Direct interaction inside the protein with non-annular lipids; (ii) close interaction with the first shell of annular lipids; (iii) regulation of membrane biophysical properties (e.g., membrane lipid packing, thickness, and curvature) directly around the protein through annular lipids; and (iv) gathering and downstream signaling of several proteins inside lipid domains. We finally discuss recent reports supporting the related alteration of Ca2+ and lipids in different pathophysiological events and the possibility to target lipids in Ca2+-related diseases.
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Affiliation(s)
- Louise Conrard
- CELL Unit, de Duve Institute and Université catholique de Louvain, UCL B1.75.05, avenue Hippocrate, 75, B-1200 Brussels, Belgium
| | - Donatienne Tyteca
- CELL Unit, de Duve Institute and Université catholique de Louvain, UCL B1.75.05, avenue Hippocrate, 75, B-1200 Brussels, Belgium.
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12
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Melzak KA, Uhlig S, Kirschhöfer F, Brenner-Weiss G, Bieback K. The Blood Bag Plasticizer Di-2-Ethylhexylphthalate Causes Red Blood Cells to Form Stomatocytes, Possibly by Inducing Lipid Flip-Flop. Transfus Med Hemother 2018; 45:413-422. [PMID: 30574059 DOI: 10.1159/000490502] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 05/26/2018] [Indexed: 12/13/2022] Open
Abstract
Background During storage of red blood cell (RBC) concentrates, the plasticizer di-2-ethylhexylphthalate (DEHP) that keeps the blood bags soft leaches out and can be taken up by the RBCs. DEHP is known to be beneficial for the RBC storage quality, but the molecular mechanisms of the action are unknown. Methods Aqueous suspensions of DEHP were added to RBCs in buffer. The morphological effects were observed on RBCs from 5 donors. Flow cytometry with annexin A5 binding was used to measure the exposed phosphatidylserine. Results DEHP induced the formation of stomatocytes at concentrations as low as ng/ml, provided that the cell suspension was also sufficiently dilute. Some spherocytes, which were susceptible to lysis, were also formed; after lysis, RBC ghosts were seen to continue the transition to the cup-shaped stomatocyte form. Incubation with DEHP increased the exposed phosphatidylserine, an effect that was also observed in the presence of vanadate, which inhibits the ATP-dependent translocases that maintain the membrane's lipid asymmetry. Conclusions DEHP can have an active effect on RBC shape, instead of just preventing the storage-related shape changes. The effect appears to be mediated by increased flip-flop of lipids between the leaflets of the RBC membrane.
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Affiliation(s)
- Kathryn A Melzak
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Stefanie Uhlig
- Institute for Transfusion Medicine and Immunology, Flowcore Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Frank Kirschhöfer
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Gerald Brenner-Weiss
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Karen Bieback
- Institute for Transfusion Medicine and Immunology, Flowcore Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
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13
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Pollet H, Conrard L, Cloos AS, Tyteca D. Plasma Membrane Lipid Domains as Platforms for Vesicle Biogenesis and Shedding? Biomolecules 2018; 8:E94. [PMID: 30223513 PMCID: PMC6164003 DOI: 10.3390/biom8030094] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 09/03/2018] [Accepted: 09/04/2018] [Indexed: 12/18/2022] Open
Abstract
Extracellular vesicles (EVs) contribute to several pathophysiological processes and appear as emerging targets for disease diagnosis and therapy. However, successful translation from bench to bedside requires deeper understanding of EVs, in particular their diversity, composition, biogenesis and shedding mechanisms. In this review, we focus on plasma membrane-derived microvesicles (MVs), far less appreciated than exosomes. We integrate documented mechanisms involved in MV biogenesis and shedding, focusing on the red blood cell as a model. We then provide a perspective for the relevance of plasma membrane lipid composition and biophysical properties in microvesiculation on red blood cells but also platelets, immune and nervous cells as well as tumor cells. Although only a few data are available in this respect, most of them appear to converge to the idea that modulation of plasma membrane lipid content, transversal asymmetry and lateral heterogeneity in lipid domains may play a significant role in the vesiculation process. We suggest that lipid domains may represent platforms for inclusion/exclusion of membrane lipids and proteins into MVs and that MVs could originate from distinct domains during physiological processes and disease evolution.
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Affiliation(s)
- Hélène Pollet
- CELL Unit, de Duve Institute & Université Catholique de Louvain, UCL B1.75.05, Avenue Hippocrate, 75, B-1200 Brussels, Belgium.
| | - Louise Conrard
- CELL Unit, de Duve Institute & Université Catholique de Louvain, UCL B1.75.05, Avenue Hippocrate, 75, B-1200 Brussels, Belgium.
| | - Anne-Sophie Cloos
- CELL Unit, de Duve Institute & Université Catholique de Louvain, UCL B1.75.05, Avenue Hippocrate, 75, B-1200 Brussels, Belgium.
| | - Donatienne Tyteca
- CELL Unit, de Duve Institute & Université Catholique de Louvain, UCL B1.75.05, Avenue Hippocrate, 75, B-1200 Brussels, Belgium.
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14
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Degosserie J, Heymans C, Spourquet C, Halbout M, D'Auria L, Van Der Smissen P, Vertommen D, Courtoy PJ, Tyteca D, Pierreux CE. Extracellular vesicles from endothelial progenitor cells promote thyroid follicle formation. J Extracell Vesicles 2018; 7:1487250. [PMID: 29963298 PMCID: PMC6022243 DOI: 10.1080/20013078.2018.1487250] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 06/03/2018] [Indexed: 01/08/2023] Open
Abstract
Organogenesis is a complex and dynamic process requiring reciprocal communication between different cell types. In the thyroid, thyrocyte progenitors secrete the angiocrine factor, VEGFA, to recruit endothelial cells. In return, endothelial cells promote thyrocyte organisation into spherical follicular structures, which are responsible for thyroid hormone synthesis and storage. Medium conditioned by endothelial progenitor cells (EPCs) can promote follicle formation and lumen expansion (i.e. folliculogenesis) in an ex vivo culture system of thyroid lobes. Here, we postulated that endothelial cells instruct thyrocyte progenitors by producing extracellular vesicles (EVs). We found that medium conditioned by EPCs contain EVs with exosomal characteristics and that these vesicles can be incorporated into thyrocyte progenitors. By mass spectrometry, laminin peptides were abundantly identified in the EV preparations, probably co-sedimenting with EVs. Laminin-α1 silencing in EPC abrogated the folliculogenic effect of EVs. However, density gradient separation of EVs from laminins revealed that both EV-rich and laminin-rich fractions exhibited folliculogenic activity. In conclusion, we suggest that endothelial cells can produce EVs favouring thyrocyte organisation into follicles and lumen expansion, a mechanism promoted by laminin-α1.
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Affiliation(s)
- Jonathan Degosserie
- CELL Unit, de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Charlotte Heymans
- CELL Unit, de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Catherine Spourquet
- CELL Unit, de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Mathias Halbout
- BCHM Unit, de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Ludovic D'Auria
- Neurochemistry group, CEMO division, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Patrick Van Der Smissen
- CELL Unit, de Duve Institute, Université Catholique de Louvain, Brussels, Belgium.,PICT plateform, de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Didier Vertommen
- PHOS Unit, de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Pierre J Courtoy
- CELL Unit, de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Donatienne Tyteca
- CELL Unit, de Duve Institute, Université Catholique de Louvain, Brussels, Belgium.,PICT plateform, de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
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15
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Mound A, Lozanova V, Warnon C, Hermant M, Robic J, Guere C, Vie K, Lambert de Rouvroit C, Tyteca D, Debacq-Chainiaux F, Poumay Y. Non-senescent keratinocytes organize in plasma membrane submicrometric lipid domains enriched in sphingomyelin and involved in re-epithelialization. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:958-971. [DOI: 10.1016/j.bbalip.2017.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 04/26/2017] [Accepted: 06/03/2017] [Indexed: 12/22/2022]
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16
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Leonard C, Conrard L, Guthmann M, Pollet H, Carquin M, Vermylen C, Gailly P, Van Der Smissen P, Mingeot-Leclercq MP, Tyteca D. Contribution of plasma membrane lipid domains to red blood cell (re)shaping. Sci Rep 2017; 7:4264. [PMID: 28655935 PMCID: PMC5487352 DOI: 10.1038/s41598-017-04388-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 05/15/2017] [Indexed: 11/25/2022] Open
Abstract
Although lipid domains have been evidenced in several living cell plasma membranes, their roles remain largely unclear. We here investigated whether they could contribute to function-associated cell (re)shaping. To address this question, we used erythrocytes as cellular model since they (i) exhibit a specific biconcave shape, allowing for reversible deformation in blood circulation, which is lost by membrane vesiculation upon aging; and (ii) display at their outer plasma membrane leaflet two types of submicrometric domains differently enriched in cholesterol and sphingomyelin. We here reveal the specific association of cholesterol- and sphingomyelin-enriched domains with distinct curvature areas of the erythrocyte biconcave membrane. Upon erythrocyte deformation, cholesterol-enriched domains gathered in high curvature areas. In contrast, sphingomyelin-enriched domains increased in abundance upon calcium efflux during shape restoration. Upon erythrocyte storage at 4 °C (to mimick aging), lipid domains appeared as specific vesiculation sites. Altogether, our data indicate that lipid domains could contribute to erythrocyte function-associated (re)shaping.
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Affiliation(s)
- C Leonard
- FACM Unit, Louvain Drug Research Institute & Université catholique de Louvain, 1200, Brussels, Belgium.,CELL Unit, de Duve Institute & Université catholique de Louvain, 1200, Brussels, Belgium
| | - L Conrard
- CELL Unit, de Duve Institute & Université catholique de Louvain, 1200, Brussels, Belgium
| | - M Guthmann
- CELL Unit, de Duve Institute & Université catholique de Louvain, 1200, Brussels, Belgium
| | - H Pollet
- CELL Unit, de Duve Institute & Université catholique de Louvain, 1200, Brussels, Belgium
| | - M Carquin
- CELL Unit, de Duve Institute & Université catholique de Louvain, 1200, Brussels, Belgium
| | - C Vermylen
- PEDI Unit, Institut de Recherche expérimentale et clinique & Université catholique de Louvain, 1200, Brussels, Belgium
| | - P Gailly
- CEMO Unit, Institute of Neuroscience & Université catholique de Louvain, 1200, Brussels, Belgium
| | - P Van Der Smissen
- CELL Unit, de Duve Institute & Université catholique de Louvain, 1200, Brussels, Belgium
| | - M P Mingeot-Leclercq
- FACM Unit, Louvain Drug Research Institute & Université catholique de Louvain, 1200, Brussels, Belgium
| | - D Tyteca
- CELL Unit, de Duve Institute & Université catholique de Louvain, 1200, Brussels, Belgium.
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17
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D’Auria L, Reiter C, Ward E, Moyano AL, Marshall MS, Nguyen D, Scesa G, Hauck Z, van Breemen R, Givogri MI, Bongarzone ER. Psychosine enhances the shedding of membrane microvesicles: Implications in demyelination in Krabbe's disease. PLoS One 2017; 12:e0178103. [PMID: 28531236 PMCID: PMC5439731 DOI: 10.1371/journal.pone.0178103] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 05/06/2017] [Indexed: 12/22/2022] Open
Abstract
In prior studies, our laboratory showed that psychosine accumulates and disrupts lipid rafts in brain membranes of Krabbe’s disease. A model of lipid raft disruption helped explaining psychosine’s effects on several signaling pathways important for oligodendrocyte survival and differentiation but provided more limited insight in how this sphingolipid caused demyelination. Here, we have studied how this cationic inverted coned lipid affects the fluidity, stability and structure of myelin and plasma membranes. Using a combination of cutting-edge imaging techniques in non-myelinating (red blood cell), and myelinating (oligodendrocyte) cell models, we show that psychosine is sufficient to disrupt sphingomyelin-enriched domains, increases the rigidity of localized areas in the plasma membrane, and promotes the shedding of membranous microvesicles. The same physicochemical and structural changes were measured in myelin membranes purified from the mutant mouse Twitcher, a model for Krabbe’s disease. Areas of higher rigidity were measured in Twitcher myelin and correlated with higher levels of psychosine and of myelin microvesiculation. These results expand our previous analyses and support, for the first time a pathogenic mechanism where psychosine’s toxicity in Krabbe disease involves deregulation of cell signaling not only by disruption of membrane rafts, but also by direct local destabilization and fragmentation of the membrane through microvesiculation. This model of membrane disruption may be fundamental to introduce focal weak points in the myelin sheath, and consequent diffuse demyelination in this leukodystrophy, with possible commonality to other demyelinating disorders.
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Affiliation(s)
- Ludovic D’Auria
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, Chicago, Illinois, United States of America
| | - Cory Reiter
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, Chicago, Illinois, United States of America
| | - Emma Ward
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, Chicago, Illinois, United States of America
| | - Ana Lis Moyano
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, Chicago, Illinois, United States of America
| | - Michael S. Marshall
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, Chicago, Illinois, United States of America
| | - Duc Nguyen
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, Chicago, Illinois, United States of America
| | - Giuseppe Scesa
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, Chicago, Illinois, United States of America
| | - Zane Hauck
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois, Chicago, Illinois, United States of America
| | - Richard van Breemen
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois, Chicago, Illinois, United States of America
| | - Maria I. Givogri
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, Chicago, Illinois, United States of America
| | - Ernesto R. Bongarzone
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, Chicago, Illinois, United States of America
- Departamento de Química Biologica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
- * E-mail:
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18
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Kraft ML. Sphingolipid Organization in the Plasma Membrane and the Mechanisms That Influence It. Front Cell Dev Biol 2017; 4:154. [PMID: 28119913 PMCID: PMC5222807 DOI: 10.3389/fcell.2016.00154] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 12/27/2016] [Indexed: 11/13/2022] Open
Abstract
Sphingolipids are structural components in the plasma membranes of eukaryotic cells. Their metabolism produces bioactive signaling molecules that modulate fundamental cellular processes. The segregation of sphingolipids into distinct membrane domains is likely essential for cellular function. This review presents the early studies of sphingolipid distribution in the plasma membranes of mammalian cells that shaped the most popular current model of plasma membrane organization. The results of traditional imaging studies of sphingolipid distribution in stimulated and resting cells are described. These data are compared with recent results obtained with advanced imaging techniques, including super-resolution fluorescence detection and high-resolution secondary ion mass spectrometry (SIMS). Emphasis is placed on the new insight into the sphingolipid organization within the plasma membrane that has resulted from the direct imaging of stable isotope-labeled lipids in actual cell membranes with high-resolution SIMS. Super-resolution fluorescence techniques have recently revealed the biophysical behaviors of sphingolipids and the unhindered diffusion of cholesterol analogs in the membranes of living cells are ultimately in contrast to the prevailing hypothetical model of plasma membrane organization. High-resolution SIMS studies also conflicted with the prevailing hypothesis, showing sphingolipids are concentrated in micrometer-scale membrane domains, but cholesterol is evenly distributed within the plasma membrane. Reductions in cellular cholesterol decreased the number of sphingolipid domains in the plasma membrane, whereas disruption of the cytoskeleton eliminated them. In addition, hemagglutinin, a transmembrane protein that is thought to be a putative raft marker, did not cluster within sphingolipid-enriched regions in the plasma membrane. Thus, sphingolipid distribution in the plasma membrane is dependent on the cytoskeleton, but not on favorable interactions with cholesterol or hemagglutinin. The alternate views of plasma membrane organization suggested by these findings are discussed.
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Affiliation(s)
- Mary L Kraft
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana, IL, USA
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19
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Shirey CM, Ward KE, Stahelin RV. Investigation of the biophysical properties of a fluorescently modified ceramide-1-phosphate. Chem Phys Lipids 2016; 200:32-41. [PMID: 27318040 DOI: 10.1016/j.chemphyslip.2016.06.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 06/14/2016] [Indexed: 12/11/2022]
Abstract
Ceramide-1-phosphate (C1P) is an important signaling sphingolipid and a metabolite of ceramide. C1P contains an anionic phosphomonoester head group and has been shown to regulate physiological and pathophysiological processes such as cell proliferation, inflammation, apoptosis, phagocytosis, and macrophage chemotaxis. Despite this mechanistic information on its role in intra- and intercellular communication, little information is available on the biophysical properties of C1P in biological membranes and how it interacts with effector proteins. Fluorescently labeled lipids have been a useful tool to understand the membrane behavior properties of lipids such as phosphatidylserine, cholesterol, and some phosphoinositides. However, to the best of our knowledge, fluorescently labeled C1P hasn't been implemented to investigate its ability to serve as a mimetic of endogenous C1P in cells or untagged C1P in in vitro experiments. Cellular and in vitro assays demonstrate TopFluor-C1P harbors a fluorescent group that is fully buried in the hydrocarbon core and fluoresces across the spectrum of physiological pH values. Moreover, TopFluor-C1P didn't affect cellular toxicity at concentrations employed, was as effective as unlabeled C1P in recruiting an established protein effector to intracellular membranes, and its subcellular localization recapitulated what is known for endogenous C1P. Notably, the diffusion coefficient of TopFluor-C1P was slower than that of TopFluor-phosphatidylserine or TopFluor-cholesterol in the plasma membrane and similar to that of other fluorescently labeled sphingolipids including ceramide and sphingomyelin. These studies demonstrate that TopFluor-C1P should be a reliable mimetic of C1P to study C1P membrane biophysical properties and C1P interactions with proteins.
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Affiliation(s)
- Carolyn M Shirey
- Department of Chemistry and Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, United States
| | - Katherine E Ward
- Department of Chemistry and Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, United States
| | - Robert V Stahelin
- Department of Chemistry and Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, United States; Department of Biochemistry and Molecular Biology, Indiana University School of Medicine-South Bend, South Bend, IN 46617, United States.
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20
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Transmembrane voltage: Potential to induce lateral microdomains. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:806-811. [PMID: 26902513 DOI: 10.1016/j.bbalip.2016.02.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 02/16/2016] [Accepted: 02/17/2016] [Indexed: 12/17/2022]
Abstract
Lateral segregation of plasma membrane lipids is a generally accepted phenomenon. Lateral lipid microdomains of specific composition, structure and biological functions are established as a result of simultaneous action of several competing mechanisms which contribute to membrane organization. Various lines of evidence support the conclusion that among those mechanisms, the membrane potential plays significant and to some extent unique role. Above all, clear differences in the microdomain structure as revealed by fluorescence microscopy could be recognized between polarized and depolarized membranes. In addition, recent fluorescence spectroscopy experiments reported depolarization-induced changes in a membrane lipid order. In the context of earlier findings showing that plasma membranes of depolarized cells are less susceptible to detergents and the cells less sensitive to antibiotics or antimycotics treatment we discuss a model, in which membrane potential-driven re-organization of the microdomain structure contributes to maintaining membrane integrity during response to stress, pathogen attack and other challenges involving partial depolarization of the plasma membrane. This article is part of a Special Issue entitled: The cellular lipid landscape edited by Tim P. Levine and Anant K. Menon.
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Carquin M, D'Auria L, Pollet H, Bongarzone ER, Tyteca D. Recent progress on lipid lateral heterogeneity in plasma membranes: From rafts to submicrometric domains. Prog Lipid Res 2015; 62:1-24. [PMID: 26738447 DOI: 10.1016/j.plipres.2015.12.004] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 12/22/2015] [Accepted: 12/22/2015] [Indexed: 12/29/2022]
Abstract
The concept of transient nanometric domains known as lipid rafts has brought interest to reassess the validity of the Singer-Nicolson model of a fluid bilayer for cell membranes. However, this new view is still insufficient to explain the cellular control of surface lipid diversity or membrane deformability. During the past decades, the hypothesis that some lipids form large (submicrometric/mesoscale vs nanometric rafts) and stable (>min vs s) membrane domains has emerged, largely based on indirect methods. Morphological evidence for stable submicrometric lipid domains, well-accepted for artificial and highly specialized biological membranes, was further reported for a variety of living cells from prokaryot es to yeast and mammalian cells. However, results remained questioned based on limitations of available fluorescent tools, use of poor lipid fixatives, and imaging artifacts due to non-resolved membrane projections. In this review, we will discuss recent evidence generated using powerful and innovative approaches such as lipid-specific toxin fragments that support the existence of submicrometric domains. We will integrate documented mechanisms involved in the formation and maintenance of these domains, and provide a perspective on their relevance on membrane deformability and regulation of membrane protein distribution.
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Affiliation(s)
- Mélanie Carquin
- CELL Unit, de Duve Institute & Université Catholique de Louvain, UCL B1.75.05, Avenue Hippocrate, 75, B-1200 Brussels, Belgium
| | - Ludovic D'Auria
- The Myelin Regeneration Group at the Dept. Anatomy & Cell Biology, College of Medicine, University of Illinois, 808 S. Wood St. MC512, Chicago, IL. 60612. USA
| | - Hélène Pollet
- CELL Unit, de Duve Institute & Université Catholique de Louvain, UCL B1.75.05, Avenue Hippocrate, 75, B-1200 Brussels, Belgium
| | - Ernesto R Bongarzone
- The Myelin Regeneration Group at the Dept. Anatomy & Cell Biology, College of Medicine, University of Illinois, 808 S. Wood St. MC512, Chicago, IL. 60612. USA
| | - Donatienne Tyteca
- CELL Unit, de Duve Institute & Université Catholique de Louvain, UCL B1.75.05, Avenue Hippocrate, 75, B-1200 Brussels, Belgium.
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22
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Carquin M, Conrard L, Pollet H, Van Der Smissen P, Cominelli A, Veiga-da-Cunha M, Courtoy PJ, Tyteca D. Cholesterol segregates into submicrometric domains at the living erythrocyte membrane: evidence and regulation. Cell Mol Life Sci 2015; 72:4633-51. [PMID: 26077601 PMCID: PMC11113096 DOI: 10.1007/s00018-015-1951-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 05/07/2015] [Accepted: 06/04/2015] [Indexed: 01/01/2023]
Abstract
Although cholesterol is essential for membrane fluidity and deformability, the level of its lateral heterogeneity at the plasma membrane of living cells is poorly understood due to lack of appropriate probe. We here report on the usefulness of the D4 fragment of Clostridium perfringens toxin fused to mCherry (theta*), as specific, non-toxic, sensitive and quantitative cholesterol-labeling tool, using erythrocyte flat membrane. By confocal microscopy, theta* labels cholesterol-enriched submicrometric domains in coverslip-spread but also gel-suspended (non-stretched) fresh erythrocytes, suggesting in vivo relevance. Cholesterol domains on spread erythrocytes are stable in time and space, restricted by membrane:spectrin anchorage via 4.1R complexes, and depend on temperature and sphingomyelin, indicating combined regulation by extrinsic membrane:cytoskeleton interaction and by intrinsic lipid packing. Cholesterol domains partially co-localize with BODIPY-sphingomyelin-enriched domains. In conclusion, we show that theta* is a useful vital probe to study cholesterol organization and demonstrate that cholesterol forms submicrometric domains in living cells.
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Affiliation(s)
- Mélanie Carquin
- CELL Unit, de Duve Institute and Université Catholique de Louvain, UCL B1.75.05, Avenue Hippocrate, 75, 1200, Brussels, Belgium
| | - Louise Conrard
- CELL Unit, de Duve Institute and Université Catholique de Louvain, UCL B1.75.05, Avenue Hippocrate, 75, 1200, Brussels, Belgium
| | - Hélène Pollet
- CELL Unit, de Duve Institute and Université Catholique de Louvain, UCL B1.75.05, Avenue Hippocrate, 75, 1200, Brussels, Belgium
| | - Patrick Van Der Smissen
- CELL Unit, de Duve Institute and Université Catholique de Louvain, UCL B1.75.05, Avenue Hippocrate, 75, 1200, Brussels, Belgium
| | - Antoine Cominelli
- CELL Unit, de Duve Institute and Université Catholique de Louvain, UCL B1.75.05, Avenue Hippocrate, 75, 1200, Brussels, Belgium
| | - Maria Veiga-da-Cunha
- Laboratory of Physiological Chemistry, de Duve Institute and Université Catholique de Louvain, 1200, Brussels, Belgium
| | - Pierre J Courtoy
- CELL Unit, de Duve Institute and Université Catholique de Louvain, UCL B1.75.05, Avenue Hippocrate, 75, 1200, Brussels, Belgium
| | - Donatienne Tyteca
- CELL Unit, de Duve Institute and Université Catholique de Louvain, UCL B1.75.05, Avenue Hippocrate, 75, 1200, Brussels, Belgium.
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23
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García-Martínez V, Montes MA, Villanueva J, Gimenez-Molina Y, de Toledo GA, Gutiérrez LM. Sphingomyelin derivatives increase the frequency of microvesicle and granule fusion in chromaffin cells. Neuroscience 2015; 295:117-25. [PMID: 25813703 DOI: 10.1016/j.neuroscience.2015.03.036] [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: 12/17/2014] [Revised: 03/18/2015] [Accepted: 03/18/2015] [Indexed: 10/23/2022]
Abstract
Sphingomyelin derivatives like sphingosine have been shown to enhance secretion in a variety of systems, including neuroendocrine and neuronal cells. By studying the mechanisms underlying this effect, we demonstrate here that sphingomyelin rafts co-localize strongly with synaptosomal-associated protein of 25Kda (SNAP-25) clusters in cultured bovine chromaffin cells and that they appear to be linked in a dynamic manner. In functional terms, when cultured rat chromaffin cells are treated with sphingomyelinase (SMase), producing sphingomyelin derivatives, the secretion elicited by repetitive depolarizations is enhanced. This increase was independent of cell size and it was significant 15min after initiating stimulation. Interestingly, by evaluating the membrane capacitance we found that the events in control untreated cells corresponded to two populations of microvesicles and granules, and the fusion of both these populations is clearly enhanced after treatment with SMase. Furthermore, SMase does not increase the size of chromaffin granules. Together, these results strongly suggest that SNARE-mediated exocytosis is enhanced by the generation of SMase derivatives, reflecting an increase in the frequency of fusion of both microvesicles and chromaffin granules rather than an increase in the size of these vesicles.
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Affiliation(s)
- V García-Martínez
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante 03550, Spain
| | - M A Montes
- Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, 41009 Sevilla, Spain
| | - J Villanueva
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante 03550, Spain
| | - Y Gimenez-Molina
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante 03550, Spain
| | - G A de Toledo
- Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, 41009 Sevilla, Spain
| | - L M Gutiérrez
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante 03550, Spain.
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24
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Tyteca D, Nishino T, Debaix H, Van Der Smissen P, N'Kuli F, Hoffmann D, Cnops Y, Rabolli V, van Loo G, Beyaert R, Huaux F, Devuyst O, Courtoy PJ. Regulation of macrophage motility by the water channel aquaporin-1: crucial role of M0/M2 phenotype switch. PLoS One 2015; 10:e0117398. [PMID: 25719758 PMCID: PMC4342038 DOI: 10.1371/journal.pone.0117398] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 12/22/2014] [Indexed: 12/21/2022] Open
Abstract
The water channel aquaporin-1 (AQP1) promotes migration of many cell types. Although AQP1 is expressed in macrophages, its potential role in macrophage motility, particularly in relation with phenotype polarization, remains unknown. We here addressed these issues in peritoneal macrophages isolated from AQP1-deficient mice, either undifferentiated (M0) or stimulated with LPS to orientate towards pro-inflammatory phenotype (classical macrophage activation; M1). In non-stimulated macrophages, ablation of AQP1 (like inhibition by HgCl2) increased by 2-3 fold spontaneous migration in a Src/PI3K/Rac-dependent manner. This correlated with cell elongation and formation of lamellipodia/ruffles, resulting in membrane lipid and F4/80 recruitment to the leading edge. This indicated that AQP1 normally suppresses migration of resting macrophages, as opposed to other cell types. Resting Aqp1-/- macrophages exhibited CD206 redistribution into ruffles and increased arginase activity like IL4/IL13 (alternative macrophage activation; M2), indicating a M0-M2 shift. In contrast, upon M1 orientation by LPS in vitro or peritoneal inflammation in vivo, migration of Aqp1-/- macrophages was reduced. Taken together, these data indicate that AQP1 oppositely regulates macrophage migration, depending on stimulation or not by LPS, and that macrophage phenotypic and migratory changes may be regulated independently of external cues.
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Affiliation(s)
- Donatienne Tyteca
- CELL Unit, de Duve Institute (DDUV), Université catholique de Louvain, Brussels, Belgium
| | - Tomoya Nishino
- Pôle de Néphrologie (NEFR), Institut de recherche expérimentale et clinique (IREC), Université catholique de Louvain, Brussels, Belgium
- Division of Nephrology, Nagasaki University, Nagasaki, Japan
| | - Huguette Debaix
- Pôle de Néphrologie (NEFR), Institut de recherche expérimentale et clinique (IREC), Université catholique de Louvain, Brussels, Belgium
| | | | - Francisca N'Kuli
- CELL Unit, de Duve Institute (DDUV), Université catholique de Louvain, Brussels, Belgium
| | - Delia Hoffmann
- CELL Unit, de Duve Institute (DDUV), Université catholique de Louvain, Brussels, Belgium
| | - Yvette Cnops
- Pôle de Néphrologie (NEFR), Institut de recherche expérimentale et clinique (IREC), Université catholique de Louvain, Brussels, Belgium
| | - Virginie Rabolli
- Louvain Centre for Toxicology and Applied Pharmacology (LTAP), Institut de recherche expérimentale et clinique (IREC), Université catholique de Louvain, Brussels, Belgium
| | - Geert van Loo
- Inflammation Research Center, VIB, Department of Biomedical Molecular Biology, University of Ghent, Ghent, Belgium
| | - Rudi Beyaert
- Inflammation Research Center, VIB, Department of Biomedical Molecular Biology, University of Ghent, Ghent, Belgium
| | - François Huaux
- Louvain Centre for Toxicology and Applied Pharmacology (LTAP), Institut de recherche expérimentale et clinique (IREC), Université catholique de Louvain, Brussels, Belgium
| | - Olivier Devuyst
- Pôle de Néphrologie (NEFR), Institut de recherche expérimentale et clinique (IREC), Université catholique de Louvain, Brussels, Belgium
| | - Pierre J. Courtoy
- CELL Unit, de Duve Institute (DDUV), Université catholique de Louvain, Brussels, Belgium
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25
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Abstract
“Lipid raft” is the name given to the tiny, dynamic, and ordered domains of cholesterol and sphingolipids that are hypothesized to exist in the plasma membranes of eukaryotic cells. According to the lipid raft hypothesis, these cholesterol- and sphingolipid-enriched domains modulate the protein–protein interactions that are essential for cellular function. Indeed, many studies have shown that cellular levels of cholesterol and sphingolipids influence plasma membrane organization, cell signaling, and other important biological processes. Despite 15 years of research and the application of highly advanced imaging techniques, data that unambiguously demonstrate the existence of lipid rafts in mammalian cells are still lacking. This Perspective summarizes the results that challenge the lipid raft hypothesis and discusses alternative hypothetical models of plasma membrane organization and lipid-mediated cellular function.
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Affiliation(s)
- Mary L Kraft
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL 61801
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26
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Carquin M, Pollet H, Veiga-da-Cunha M, Cominelli A, Van Der Smissen P, N'kuli F, Emonard H, Henriet P, Mizuno H, Courtoy PJ, Tyteca D. Endogenous sphingomyelin segregates into submicrometric domains in the living erythrocyte membrane. J Lipid Res 2014; 55:1331-42. [PMID: 24826836 DOI: 10.1194/jlr.m048538] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Indexed: 11/20/2022] Open
Abstract
We recently reported that trace insertion of exogenous fluorescent (green BODIPY) analogs of sphingomyelin (SM) into living red blood cells (RBCs), partially spread onto coverslips, labels submicrometric domains, visible by confocal microscopy. We here extend this feature to endogenous SM, upon binding of a SM-specific nontoxic (NT) fragment of the earthworm toxin, lysenin, fused to the red monomeric fluorescent protein, mCherry [construct named His-mCherry-NT-lysenin (lysenin*)]. Specificity of lysenin* binding was verified with composition-defined liposomes and by loss of (125)I-lysenin* binding to erythrocytes upon SM depletion by SMase. The (125)I-lysenin* binding isotherm indicated saturation at 3.5 × 10(6) molecules/RBC, i.e., ∼3% of SM coverage. Nonsaturating lysenin* concentration also labeled sub-micrometric domains on the plasma membrane of partially spread erythrocytes, colocalizing with inserted green BODIPY-SM, and abrogated by SMase. Lysenin*-labeled domains were stable in time and space and were regulated by temperature and cholesterol. The abundance, size, positioning, and segregation of lysenin*-labeled domains from other lipids (BODIPY-phosphatidylcholine or -glycosphingolipids) depended on membrane tension. Similar lysenin*-labeled domains were evidenced in RBCs gently suspended in 3D-gel. Taken together, these data demonstrate submicrometric compartmentation of endogenous SM at the membrane of a living cell in vitro, and suggest it may be a genuine feature of erythrocytes in vivo.
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Affiliation(s)
- Mélanie Carquin
- CELL Unit, de Duve Institute and Université catholique de Louvain, 1200 Brussels, Belgium
| | - Hélène Pollet
- CELL Unit, de Duve Institute and Université catholique de Louvain, 1200 Brussels, Belgium
| | - Maria Veiga-da-Cunha
- Laboratory of Physiological Chemistry, de Duve Institute and Université catholique de Louvain, 1200 Brussels, Belgium
| | - Antoine Cominelli
- CELL Unit, de Duve Institute and Université catholique de Louvain, 1200 Brussels, Belgium
| | | | - Francisca N'kuli
- CELL Unit, de Duve Institute and Université catholique de Louvain, 1200 Brussels, Belgium
| | - Hervé Emonard
- "Matrice Extracellulaire et Dynamique Cellulaire" Unit (MEDyC), CNRS UMR 7369, Université de Reims Champagne-Ardenne, Laboratoire SiRMa, 51 100 Reims, France
| | - Patrick Henriet
- CELL Unit, de Duve Institute and Université catholique de Louvain, 1200 Brussels, Belgium
| | - Hideaki Mizuno
- Department of Chemistry, Katholieke Universiteit Leuven, 3001 Heverlee, Belgium
| | - Pierre J Courtoy
- CELL Unit, de Duve Institute and Université catholique de Louvain, 1200 Brussels, Belgium
| | - Donatienne Tyteca
- CELL Unit, de Duve Institute and Université catholique de Louvain, 1200 Brussels, Belgium
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27
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D'Auria L, Deleu M, Dufour S, Mingeot-Leclercq MP, Tyteca D. Surfactins modulate the lateral organization of fluorescent membrane polar lipids: A new tool to study drug:membrane interaction and assessment of the role of cholesterol and drug acyl chain length. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2064-73. [DOI: 10.1016/j.bbamem.2013.05.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 04/16/2013] [Accepted: 05/08/2013] [Indexed: 12/11/2022]
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28
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Sezgin E, Levental I, Grzybek M, Schwarzmann G, Mueller V, Honigmann A, Belov VN, Eggeling C, Coskun U, Simons K, Schwille P. Partitioning, diffusion, and ligand binding of raft lipid analogs in model and cellular plasma membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1818:1777-84. [PMID: 22450237 DOI: 10.1016/j.bbamem.2012.03.007] [Citation(s) in RCA: 246] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 03/07/2012] [Accepted: 03/12/2012] [Indexed: 10/28/2022]
Abstract
Several simplified membrane models featuring coexisting liquid disordered (Ld) and ordered (Lo) lipid phases have been developed to mimic the heterogeneous organization of cellular membranes, and thus, aid our understanding of the nature and functional role of ordered lipid-protein nanodomains, termed "rafts". In spite of their greatly reduced complexity, quantitative characterization of local lipid environments using model membranes is not trivial, and the parallels that can be drawn to cellular membranes are not always evident. Similarly, various fluorescently labeled lipid analogs have been used to study membrane organization and function in vitro, although the biological activity of these probes in relation to their native counterparts often remains uncharacterized. This is particularly true for raft-preferring lipids ("raft lipids", e.g. sphingolipids and sterols), whose domain preference is a strict function of their molecular architecture, and is thus susceptible to disruption by fluorescence labeling. Here, we analyze the phase partitioning of a multitude of fluorescent raft lipid analogs in synthetic Giant Unilamellar Vesicles (GUVs) and cell-derived Giant Plasma Membrane Vesicles (GPMVs). We observe complex partitioning behavior dependent on label size, polarity, charge and position, lipid headgroup, and membrane composition. Several of the raft lipid analogs partitioned into the ordered phase in GPMVs, in contrast to fully synthetic GUVs, in which most raft lipid analogs mis-partitioned to the disordered phase. This behavior correlates with the greatly enhanced order difference between coexisting phases in the synthetic system. In addition, not only partitioning, but also ligand binding of the lipids is perturbed upon labeling: while cholera toxin B binds unlabeled GM1 in the Lo phase, it binds fluorescently labeled GMI exclusively in the Ld phase. Fluorescence correlation spectroscopy (FCS) by stimulated emission depletion (STED) nanoscopy on intact cellular plasma membranes consistently reveals a constant level of confined diffusion for raft lipid analogs that vary greatly in their partitioning behavior, suggesting different physicochemical bases for these phenomena.
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Affiliation(s)
- Erdinc Sezgin
- Biophysics/BIOTEC, TU Dresden. Tatzberg 47-51, 01307 Dresden, Germany
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29
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Direct chemical evidence for sphingolipid domains in the plasma membranes of fibroblasts. Proc Natl Acad Sci U S A 2013; 110:E613-22. [PMID: 23359681 DOI: 10.1073/pnas.1216585110] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sphingolipids play important roles in plasma membrane structure and cell signaling. However, their lateral distribution in the plasma membrane is poorly understood. Here we quantitatively analyzed the sphingolipid organization on the entire dorsal surface of intact cells by mapping the distribution of (15)N-enriched ions from metabolically labeled (15)N-sphingolipids in the plasma membrane, using high-resolution imaging mass spectrometry. Many types of control experiments (internal, positive, negative, and fixation temperature), along with parallel experiments involving the imaging of fluorescent sphingolipids--both in living cells and during fixation of living cells--exclude potential artifacts. Micrometer-scale sphingolipid patches consisting of numerous (15)N-sphingolipid microdomains with mean diameters of ∼200 nm are always present in the plasma membrane. Depletion of 30% of the cellular cholesterol did not eliminate the sphingolipid domains, but did reduce their abundance and long-range organization in the plasma membrane. In contrast, disruption of the cytoskeleton eliminated the sphingolipid domains. These results indicate that these sphingolipid assemblages are not lipid rafts and are instead a distinctly different type of sphingolipid-enriched plasma membrane domain that depends upon cortical actin.
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30
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D'Auria L, Fenaux M, Aleksandrowicz P, Van Der Smissen P, Chantrain C, Vermylen C, Vikkula M, Courtoy PJ, Tyteca D. Micrometric segregation of fluorescent membrane lipids: relevance for endogenous lipids and biogenesis in erythrocytes. J Lipid Res 2013; 54:1066-76. [PMID: 23322884 DOI: 10.1194/jlr.m034314] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Micrometric membrane lipid segregation is controversial. We addressed this issue in attached erythrocytes and found that fluorescent boron dipyrromethene (BODIPY) analogs of glycosphingolipids (GSLs) [glucosylceramide (BODIPY-GlcCer) and monosialotetrahexosylganglioside (GM1BODIPY)], sphingomyelin (BODIPY-SM), and phosphatidylcholine (BODIPY-PC inserted into the plasma membrane spontaneously gathered into distinct submicrometric domains. GM1BODIPY domains colocalized with endogenous GM1 labeled by cholera toxin. All BODIPY-lipid domains disappeared upon erythrocyte stretching, indicating control by membrane tension. Minor cholesterol depletion suppressed BODIPY-SM and BODIPY-PC but preserved BODIPY-GlcCer domains. Each type of domain exchanged constituents but assumed fixed positions, suggesting self-clustering and anchorage to spectrin. Domains showed differential association with 4.1R versus ankyrin complexes upon antibody patching. BODIPY-lipid domains also responded differentially to uncoupling at 4.1R complexes [protein kinase C (PKC) activation] and ankyrin complexes (in spherocytosis, a membrane fragility disease). These data point to micrometric compartmentation of polar BODIPY-lipids modulated by membrane tension, cholesterol, and differential association to the two nonredundant membrane:spectrin anchorage complexes. Micrometric compartmentation might play a role in erythrocyte membrane deformability and fragility.
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Affiliation(s)
- Ludovic D'Auria
- CELL Unit, Division of Hematology-Oncology, de Duve Institute and Université Catholique de Louvain, Brussels, Belgium
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31
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Kartal Yandım M, Apohan E, Baran Y. Therapeutic potential of targeting ceramide/glucosylceramide pathway in cancer. Cancer Chemother Pharmacol 2012; 71:13-20. [PMID: 23073611 DOI: 10.1007/s00280-012-1984-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 09/17/2012] [Indexed: 12/25/2022]
Abstract
Sphingolipids including ceramides and its derivatives such as ceramide-1-phosphate, glucosylceramide (GlcCer), and sphingosine-1-phosphate are essential structural components of cell membranes. They now recognized as novel bioeffector molecules which control various aspects of cell growth, proliferation, apoptosis, and drug resistance. Ceramide, the central molecule of sphingolipid metabolism, generally mediates anti-proliferative responses such as inhibition of cell growth, induction of apoptosis, and/or modulation of senescence. There are two major classes of sphingolipids. One of them is glycosphingolipids which are synthesized from the hydrophobic molecule, ceramide. GlcCer, generated by glucosylceramide synthase (GCS) that transfers the glucose from UDP-glucose to ceramide, is an important glycosphingolipid metabolic intermediate. GCS regulates the balance between apoptotic ceramide and antiapoptotic GlcCer. Downregulation or inhibition of GCS results in increased apoptosis and decreased drug resistance. The mechanism underlying the drug resistance which develops with increased glucosylceramide expression is associated with P-glycoprotein. In various types of cancers, overexpression of GCS has been observed which renders GCS a good target for the treatment of cancer. This review summarizes our current knowledge on the structure and functions of glucosylceramide synthase and glucosylceramide and on the roles of glucosylceramide synthase in cancer therapy and drug resistance.
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Affiliation(s)
- Melis Kartal Yandım
- Department of Molecular Biology and Genetics, Faculty of Science, İzmir Institute of Technology, Urla, Izmir 35430, Turkey
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32
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Mueller NS, Wedlich-Söldner R, Spira F. From mosaic to patchwork: matching lipids and proteins in membrane organization. Mol Membr Biol 2012; 29:186-96. [PMID: 22594654 DOI: 10.3109/09687688.2012.687461] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Biological membranes encompass and compartmentalize cells and organelles and are a prerequisite to life as we know it. One defining feature of membranes is an astonishing diversity of building blocks. The mechanisms and principles organizing the thousands of proteins and lipids that make up membrane bilayers in cells are still under debate. Many terms and mechanisms have been introduced over the years to account for certain phenomena and aspects of membrane organization and function. Recently, the different viewpoints - focusing on lipids vs. proteins or physical vs. molecular driving forces for membrane organization - are increasingly converging. Here we review the basic properties of biological membranes and the most common theories for lateral segregation of membrane components before discussing an emerging model of a self-organized, multi-domain membrane or 'patchwork membrane'.
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Affiliation(s)
- Nikola S Mueller
- Cellular Dynamics and Cell Patterning, Max Planck Institute of Biochemistry, Martinsried, Germany
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33
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Spira F, Mueller NS, Beck G, von Olshausen P, Beig J, Wedlich-Söldner R. Patchwork organization of the yeast plasma membrane into numerous coexisting domains. Nat Cell Biol 2012; 14:640-8. [PMID: 22544065 DOI: 10.1038/ncb2487] [Citation(s) in RCA: 168] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 03/21/2012] [Indexed: 12/29/2022]
Abstract
The plasma membrane is made up of lipids and proteins, and serves as an active interface between the cell and its environment. Many plasma-membrane proteins are laterally segregated in the plane of the membrane, but the underlying mechanisms remain controversial. Here we investigate the distribution and dynamics of a representative set of plasma-membrane-associated proteins in yeast cells. These proteins were distributed non-homogeneously in patterns ranging from distinct patches to nearly continuous networks, and these patterns were in turn strongly influenced by the lipid composition of the plasma membrane. Most proteins segregated into distinct domains. However, proteins with similar or identical transmembrane sequences (TMSs) showed a marked tendency to co-localize. Indeed we could predictably relocate proteins by swapping their TMSs. Finally, we found that the domain association of plasma-membrane proteins has an impact on their function. Our results are consistent with self-organization of biological membranes into a patchwork of coexisting domains.
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Affiliation(s)
- Felix Spira
- Cellular Dynamics and Cell Patterning, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
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34
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Ben Khalifa N, Tyteca D, Marinangeli C, Depuydt M, Collet JF, Courtoy PJ, Renauld JC, Constantinescu S, Octave JN, Kienlen-Campard P. Structural features of the KPI domain control APP dimerization, trafficking, and processing. FASEB J 2011; 26:855-67. [PMID: 22085646 DOI: 10.1096/fj.11-190207] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The two major isoforms of human APP, APP695 and APP751, differ by the presence of a Kunitz-type protease inhibitor (KPI) domain in the extracellular region. APP processing and function is thought to be regulated by homodimerization. We used bimolecular fluorescence complementation (BiFC) to study dimerization of different APP isoforms and mutants. APP751 was found to form significantly more homodimers than APP695. Mutation of dimerization motifs in the TM domain did not affect fluorescence complementation, but native folding of KPI is critical for APP751 homodimerization. APP751 and APP695 dimers were mostly localized at steady state in the Golgi region, suggesting that most of the APP751 and 695 dimers are in the secretory pathway. Mutation of the KPI led to the retention of the APP homodimers in the endoplasmic reticulum. We finally showed that APP751 is more efficiently processed through the nonamyloidogenic pathway than APP695. These findings provide new insight on the particular role of KPI domain in APP dimerization. The correlation observed between dimerization, subcellular localization, and processing suggests that dimerization acts as an efficient regulator of APP trafficking in the secretory compartments that has major consequences on its processing.
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Affiliation(s)
- Naouel Ben Khalifa
- Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
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Abstract
Biological research has always tremendously benefited from the development of key methodology. In fact, it was the advent of microscopy that shaped our understanding of cells as the fundamental units of life. Microscopic techniques are still central to the elucidation of biological units and processes, but equally important are methods that allow access to the dimension of time, to investigate the dynamics of molecular functions and interactions. Here, fluorescence spectroscopy with its sensitivity to access the single-molecule level, and its large temporal resolution, has been opening up fully new perspectives for cell biology. Here we summarize the key fluorescent techniques used to study cellular dynamics, with the focus on lipid and membrane systems.
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Kavishwar A, Medarova Z, Moore A. Unique sphingomyelin patches are targets of a beta-cell-specific antibody. J Lipid Res 2011; 52:1660-71. [PMID: 21747097 DOI: 10.1194/jlr.m017582] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
To devise successful imaging and therapeutic strategies, the identification of β-cell surface markers is one of the challenges in diabetes research that has to be resolved. We previously showed that IC2, a rat monoclonal IgM antibody, can be used for ex vivo determination of β-cell mass by imaging. Further progress toward the development of an antibody-based imaging agent was hampered by the lack of knowledge regarding the nature and composition of the IC2 antigen. Here, we show a series of systematic experiments involving classical lipid extraction and chromatography techniques combined with immunochemistry, which led to the identification of sphingomyelin as the target antigen assembled in the form of patches on the β-cell surface. Our findings were verified by modulating SM by enzymatic cleavage, downregulation, upregulation, and perturbation of membrane SM and observation of corresponding changes in IC2 binding. Cholesterol participates in stabilization of these patches, as its removal results in loss of IC2 binding. We believe that these findings have implications for identifying future ligands for the proposed antigen for imaging purposes as well as for potential therapy, as sphingomyelin has been shown to play a role in the apoptotic cascade in pancreatic β cells.
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Affiliation(s)
- Amol Kavishwar
- Molecular Imaging Laboratory, MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA
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Mikhalyov I, Samsonov A. Lipid raft detecting in membranes of live erythrocytes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1930-9. [DOI: 10.1016/j.bbamem.2011.04.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 03/15/2011] [Accepted: 04/04/2011] [Indexed: 11/27/2022]
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Selvais C, D'Auria L, Tyteca D, Perrot G, Lemoine P, Troeberg L, Dedieu S, Noël A, Nagase H, Henriet P, Courtoy PJ, Marbaix E, Emonard H. Cell cholesterol modulates metalloproteinase-dependent shedding of low-density lipoprotein receptor-related protein-1 (LRP-1) and clearance function. FASEB J 2011; 25:2770-81. [PMID: 21518850 DOI: 10.1096/fj.10-169508] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Low-density lipoprotein receptor-related protein-1 (LRP-1) is a plasma membrane scavenger and signaling receptor, composed of a large ligand-binding subunit (515-kDa α-chain) linked to a shorter transmembrane subunit (85-kDa β-chain). LRP-1 cell-surface level and function are controlled by proteolytic shedding of its ectodomain. Here, we identified ectodomain sheddases in human HT1080 cells and demonstrated regulation of the cleavage by cholesterol by comparing the classical fibroblastoid type with a spontaneous epithelioid variant, enriched ∼ 2-fold in cholesterol. Two membrane-associated metalloproteinases were involved in LRP-1 shedding: a disintegrin and metalloproteinase-12 (ADAM-12) and membrane-type 1 matrix metalloproteinase (MT1-MMP). Although both variants expressed similar levels of LRP-1, ADAM-12, MT1-MMP, and specific tissue inhibitor of metalloproteinases-2 (TIMP-2), LRP-1 shedding from epithelioid cells was ∼4-fold lower than from fibroblastoid cells. Release of the ectodomain was triggered by cholesterol depletion in epithelioid cells and impaired by cholesterol overload in fibroblastoid cells. Modulation of LRP-1 shedding on clearance was reflected by accumulation of gelatinases (MMP-2 and MMP-9) in the medium. We conclude that cholesterol exerts an important control on LRP-1 levels and function at the plasma membrane by modulating shedding of its ectodomain, and therefore represents a novel regulator of extracellular proteolytic activities.
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Affiliation(s)
- Charlotte Selvais
- Cell Biology Laboratory, de Duve Institute, UCL-75.41, 75 avenue Hippocrate, B-1200 Bruxelles, Belgium
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D′auria L, Van Der Smissen P, Bruyneel F, Courtoy PJ, Tyteca D. Segregation of fluorescent membrane lipids into distinct micrometric domains: evidence for phase compartmentation of natural lipids? PLoS One 2011; 6:e17021. [PMID: 21386970 PMCID: PMC3046177 DOI: 10.1371/journal.pone.0017021] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Accepted: 01/14/2011] [Indexed: 01/06/2023] Open
Abstract
Background We recently reported that sphingomyelin (SM) analogs substituted on the alkyl chain by various fluorophores (e.g. BODIPY) readily inserted at trace levels into the plasma membrane of living erythrocytes or CHO cells and spontaneously concentrated into micrometric domains. Despite sharing the same fluorescent ceramide backbone, BODIPY-SM domains segregated from similar domains labelled by BODIPY-D-e-lactosylceramide (D-e-LacCer) and depended on endogenous SM. Methodology/Principal Findings We show here that BODIPY-SM further differed from BODIPY-D-e-LacCer or -glucosylceramide (GlcCer) domains in temperature dependence, propensity to excimer formation, association with a glycosylphosphatidylinositol (GPI)-anchored fluorescent protein reporter, and lateral diffusion by FRAP, thus demonstrating different lipid phases and boundaries. Whereas BODIPY-D-e-LacCer behaved like BODIPY-GlcCer, its artificial stereoisomer, BODIPY-L-t-LacCer, behaved like BODIPY- and NBD-phosphatidylcholine (PC). Surprisingly, these two PC analogs also formed micrometric patches yet preferably at low temperature, did not show excimer, never associated with the GPI reporter and showed major restriction to lateral diffusion when photobleached in large fields. This functional comparison supported a three-phase micrometric compartmentation, of decreasing order: BODIPY-GSLs > -SM > -PC (or artificial L-t-LacCer). Co-existence of three segregated compartments was further supported by double labelling experiments and was confirmed by additive occupancy, up to ∼70% cell surface coverage. Specific alterations of BODIPY-analogs domains by manipulation of corresponding endogenous sphingolipids suggested that distinct fluorescent lipid partition might reflect differential intrinsic propensity of endogenous membrane lipids to form large assemblies. Conclusions/Significance We conclude that fluorescent membrane lipids spontaneously concentrate into distinct micrometric assemblies. We hypothesize that these might reflect preexisting compartmentation of endogenous PM lipids into non-overlapping domains of differential order: GSLs > SM > PC, resulting into differential self-adhesion of the two former, with exclusion of the latter.
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Affiliation(s)
- Ludovic D′auria
- CELL Unit, de Duve Institute and Université catholique de Louvain, Brussels, Belgium
| | | | - Frédéric Bruyneel
- CHOM Unit, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Pierre J. Courtoy
- CELL Unit, de Duve Institute and Université catholique de Louvain, Brussels, Belgium
| | - Donatienne Tyteca
- CELL Unit, de Duve Institute and Université catholique de Louvain, Brussels, Belgium
- * E-mail:
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