1
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Magalhães DM, Stewart NA, Mampay M, Rolle SO, Hall CM, Moeendarbary E, Flint MS, Sebastião AM, Valente CA, Dymond MK, Sheridan GK. The sphingosine 1-phosphate analogue, FTY720, modulates the lipidomic signature of the mouse hippocampus. J Neurochem 2024; 168:1113-1142. [PMID: 38339785 DOI: 10.1111/jnc.16073] [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: 08/17/2023] [Revised: 12/27/2023] [Accepted: 01/22/2024] [Indexed: 02/12/2024]
Abstract
The small-molecule drug, FTY720 (fingolimod), is a synthetic sphingosine 1-phosphate (S1P) analogue currently used to treat relapsing-remitting multiple sclerosis in both adults and children. FTY720 can cross the blood-brain barrier (BBB) and, over time, accumulate in lipid-rich areas of the central nervous system (CNS) by incorporating into phospholipid membranes. FTY720 has been shown to enhance cell membrane fluidity, which can modulate the functions of glial cells and neuronal populations involved in regulating behaviour. Moreover, direct modulation of S1P receptor-mediated lipid signalling by FTY720 can impact homeostatic CNS physiology, including neurotransmitter release probability, the biophysical properties of synaptic membranes, ion channel and transmembrane receptor kinetics, and synaptic plasticity mechanisms. The aim of this study was to investigate how chronic FTY720 treatment alters the lipid composition of CNS tissue in adolescent mice at a key stage of brain maturation. We focused on the hippocampus, a brain region known to be important for learning, memory, and the processing of sensory and emotional stimuli. Using mass spectrometry-based lipidomics, we discovered that FTY720 increases the fatty acid chain length of hydroxy-phosphatidylcholine (PCOH) lipids in the mouse hippocampus. It also decreases PCOH monounsaturated fatty acids (MUFAs) and increases PCOH polyunsaturated fatty acids (PUFAs). A total of 99 lipid species were up-regulated in the mouse hippocampus following 3 weeks of oral FTY720 exposure, whereas only 3 lipid species were down-regulated. FTY720 also modulated anxiety-like behaviours in young mice but did not affect spatial learning or memory formation. Our study presents a comprehensive overview of the lipid classes and lipid species that are altered in the hippocampus following chronic FTY720 exposure and provides novel insight into cellular and molecular mechanisms that may underlie the therapeutic or adverse effects of FTY720 in the central nervous system.
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Affiliation(s)
- Daniela M Magalhães
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Lisboa, Portugal
- School of Applied Sciences, University of Brighton, Brighton, UK
| | | | - Myrthe Mampay
- School of Applied Sciences, University of Brighton, Brighton, UK
| | - Sara O Rolle
- Green Templeton College, University of Oxford, Oxford, UK
| | - Chloe M Hall
- School of Applied Sciences, University of Brighton, Brighton, UK
- Department of Mechanical Engineering, University College London, London, UK
| | - Emad Moeendarbary
- Department of Mechanical Engineering, University College London, London, UK
- 199 Biotechnologies Ltd, London, UK
| | - Melanie S Flint
- School of Applied Sciences, University of Brighton, Brighton, UK
| | - Ana M Sebastião
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Lisboa, Portugal
| | - Cláudia A Valente
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Lisboa, Portugal
| | - Marcus K Dymond
- School of Applied Sciences, University of Brighton, Brighton, UK
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2
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Paulikat M, Piccini G, Ippoliti E, Rossetti G, Arnesano F, Carloni P. Physical Chemistry of Chloroquine Permeation through the Cell Membrane with Atomistic Detail. J Chem Inf Model 2023; 63:7124-7132. [PMID: 37947485 PMCID: PMC10685453 DOI: 10.1021/acs.jcim.3c01363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 10/11/2023] [Accepted: 10/12/2023] [Indexed: 11/12/2023]
Abstract
We provide a molecular-level description of the thermodynamics and mechanistic aspects of drug permeation through the cell membrane. As a case study, we considered the antimalaria FDA approved drug chloroquine. Molecular dynamics simulations of the molecule (in its neutral and protonated form) were performed in the presence of different lipid bilayers, with the aim of uncovering key aspects of the permeation process, a fundamental step for the drug's action. Free energy values obtained by well-tempered metadynamics simulations suggest that the neutral form is the only permeating protomer, consistent with experimental data. H-bond interactions of the drug with water molecules and membrane headgroups play a crucial role for permeation. The presence of the transmembrane potential, investigated here for the first time in a drug permeation study, does not qualitatively affect these conclusions.
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Affiliation(s)
- Mirko Paulikat
- Computational
Biomedicine, Institute of Advanced Simulations IAS-5/Institute for
Neuroscience and Medicine INM-9, Forschungszentrum
Jülich GmbH, 52428 Jülich, Germany
| | - GiovanniMaria Piccini
- Institute
of Technical and Macromolecular Chemistry, RWTH Aachen University, 52074 Aachen, Germany
| | - Emiliano Ippoliti
- Computational
Biomedicine, Institute of Advanced Simulations IAS-5/Institute for
Neuroscience and Medicine INM-9, Forschungszentrum
Jülich GmbH, 52428 Jülich, Germany
| | - Giulia Rossetti
- Computational
Biomedicine, Institute of Advanced Simulations IAS-5/Institute for
Neuroscience and Medicine INM-9, Forschungszentrum
Jülich GmbH, 52428 Jülich, Germany
- Jülich
Supercomputing Centre (JSC), Forschungszentrum
Jülich GmbH, 52428 Jülich, Germany
- Department
of Neurology, RWTH Aachen University, Aachen 52062, Germany
| | - Fabio Arnesano
- Department
of Chemistry, University of Bari “Aldo
Moro”, Bari 70125, Italy
| | - Paolo Carloni
- Computational
Biomedicine, Institute of Advanced Simulations IAS-5/Institute for
Neuroscience and Medicine INM-9, Forschungszentrum
Jülich GmbH, 52428 Jülich, Germany
- Department
of Physics, RWTH Aachen University, Aachen 52062, Germany
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3
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Spears ME, Lee N, Hwang S, Park SJ, Carlisle AE, Li R, Doshi MB, Armando AM, Gao J, Simin K, Zhu LJ, Greer PL, Quehenberger O, Torres EM, Kim D. De novo sphingolipid biosynthesis necessitates detoxification in cancer cells. Cell Rep 2022; 40:111415. [PMID: 36170811 PMCID: PMC9552870 DOI: 10.1016/j.celrep.2022.111415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 07/21/2022] [Accepted: 09/02/2022] [Indexed: 11/29/2022] Open
Abstract
Sphingolipids play important signaling and structural roles in cells. Here, we find that during de novo sphingolipid biosynthesis, a toxic metabolite is formed with critical implications for cancer cell survival. The enzyme catalyzing the first step in this pathway, serine palmitoyltransferase complex (SPT), is upregulated in breast and other cancers. SPT is dispensable for cancer cell proliferation, as sphingolipids can be salvaged from the environment. However, SPT activity introduces a liability as its product, 3-ketodihydrosphingosine (3KDS), is toxic and requires clearance via the downstream enzyme 3-ketodihydrosphingosine reductase (KDSR). In cancer cells, but not normal cells, targeting KDSR induces toxic 3KDS accumulation leading to endoplasmic reticulum (ER) dysfunction and loss of proteostasis. Furthermore, the antitumor effect of KDSR disruption can be enhanced by increasing metabolic input (via high-fat diet) to allow greater 3KDS production. Thus, de novo sphingolipid biosynthesis entails a detoxification requirement in cancer cells that can be therapeutically exploited.
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Affiliation(s)
- Meghan E Spears
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Namgyu Lee
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Sunyoung Hwang
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Sung Jin Park
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Anne E Carlisle
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Rui Li
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Mihir B Doshi
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Aaron M Armando
- School of Medicine, Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, San Diego, CA 92093, USA
| | - Jenny Gao
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Karl Simin
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Lihua Julie Zhu
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Paul L Greer
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Oswald Quehenberger
- School of Medicine, Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, San Diego, CA 92093, USA
| | - Eduardo M Torres
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Dohoon Kim
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01604, USA.
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4
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Carreira AC, Pokorna S, Ventura AE, Walker MW, Futerman AH, Lloyd-Evans E, de Almeida RFM, Silva LC. Biophysical impact of sphingosine and other abnormal lipid accumulation in Niemann-Pick disease type C cell models. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158944. [PMID: 33892149 DOI: 10.1016/j.bbalip.2021.158944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 03/08/2021] [Accepted: 04/12/2021] [Indexed: 10/21/2022]
Abstract
Niemann-Pick disease type C (NPC) is a complex and rare pathology, which is mainly associated to mutations in the NPC1 gene. This disease is phenotypically characterized by the abnormal accumulation of multiple lipid species in the acidic compartments of the cell. Due to the complexity of stored material, a clear molecular mechanism explaining NPC pathophysiology is still not established. Abnormal sphingosine accumulation was suggested as the primary factor involved in the development of NPC, followed by the accumulation of other lipid species. To provide additional mechanistic insight into the role of sphingosine in NPC development, fluorescence spectroscopy and microscopy were used to study the biophysical properties of biological membranes using different cellular models of NPC. Addition of sphingosine to healthy CHO-K1 cells, in conditions where other lipid species are not yet accumulated, caused a rapid decrease in plasma membrane and lysosome membrane fluidity, suggesting a direct effect of sphingosine rather than a downstream event. Changes in membrane fluidity caused by addition of sphingosine were partially sustained upon impaired trafficking and metabolization of cholesterol in these cells, and could recapitulate the decrease in membrane fluidity observed in NPC1 null Chinese Hamster Ovary (CHO) cells (CHO-M12) and in cells with pharmacologically induced NPC phenotype (treated with U18666A). In summary, these results show for the first time that the fluidity of the membranes is altered in models of NPC and that these changes are in part caused by sphingosine, supporting the role of this lipid in the pathophysiology of NPC.
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Affiliation(s)
- Ana C Carreira
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; Centro de Química e Bioquímica (CQB) e Centro de Química Estrutural (CQE), Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016 Lisboa, Portugal; Sir Martin Evans Building, School of Biosciences, Cardiff University, Museum Avenue, Cardiff, UK
| | - Sarka Pokorna
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel; Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Ana E Ventura
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel; iBB-Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, Lisboa, Portugal
| | - Mathew W Walker
- Sir Martin Evans Building, School of Biosciences, Cardiff University, Museum Avenue, Cardiff, UK
| | - Anthony H Futerman
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Emyr Lloyd-Evans
- Sir Martin Evans Building, School of Biosciences, Cardiff University, Museum Avenue, Cardiff, UK
| | - Rodrigo F M de Almeida
- Centro de Química e Bioquímica (CQB) e Centro de Química Estrutural (CQE), Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016 Lisboa, Portugal.
| | - Liana C Silva
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal.
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5
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Inhibition of sphingolipid synthesis improves outcomes and survival in GARP mutant wobbler mice, a model of motor neuron degeneration. Proc Natl Acad Sci U S A 2020; 117:10565-10574. [PMID: 32345721 DOI: 10.1073/pnas.1913956117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Numerous mutations that impair retrograde membrane trafficking between endosomes and the Golgi apparatus lead to neurodegenerative diseases. For example, mutations in the endosomal retromer complex are implicated in Alzheimer's and Parkinson's diseases, and mutations of the Golgi-associated retrograde protein (GARP) complex cause progressive cerebello-cerebral atrophy type 2 (PCCA2). However, how these mutations cause neurodegeneration is unknown. GARP mutations in yeast, including one causing PCCA2, result in sphingolipid abnormalities and impaired cell growth that are corrected by treatment with myriocin, a sphingolipid synthesis inhibitor, suggesting that alterations in sphingolipid metabolism contribute to cell dysfunction and death. Here we tested this hypothesis in wobbler mice, a murine model with a homozygous partial loss-of-function mutation in Vps54 (GARP protein) that causes motor neuron disease. Cytotoxic sphingoid long-chain bases accumulated in embryonic fibroblasts and spinal cords from wobbler mice. Remarkably, chronic treatment of wobbler mice with myriocin markedly improved their wellness scores, grip strength, neuropathology, and survival. Proteomic analyses of wobbler fibroblasts revealed extensive missorting of lysosomal proteins, including sphingolipid catabolism enzymes, to the Golgi compartment, which may contribute to the sphingolipid abnormalities. Our findings establish that altered sphingolipid metabolism due to GARP mutations contributes to neurodegeneration and suggest that inhibiting sphingolipid synthesis might provide a useful strategy for treating these disorders.
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6
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Lang J, Bohn P, Bhat H, Jastrow H, Walkenfort B, Cansiz F, Fink J, Bauer M, Olszewski D, Ramos-Nascimento A, Duhan V, Friedrich SK, Becker KA, Krawczyk A, Edwards MJ, Burchert A, Huber M, Friebus-Kardash J, Göthert JR, Hardt C, Probst HC, Schumacher F, Köhrer K, Kleuser B, Babiychuk EB, Sodeik B, Seibel J, Greber UF, Lang PA, Gulbins E, Lang KS. Acid ceramidase of macrophages traps herpes simplex virus in multivesicular bodies and protects from severe disease. Nat Commun 2020; 11:1338. [PMID: 32165633 PMCID: PMC7067866 DOI: 10.1038/s41467-020-15072-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 02/17/2020] [Indexed: 12/20/2022] Open
Abstract
Macrophages have important protective functions during infection with herpes simplex virus type 1 (HSV-1). However, molecular mechanisms that restrict viral propagation and protect from severe disease are unclear. Here we show that macrophages take up HSV-1 via endocytosis and transport the virions into multivesicular bodies (MVBs). In MVBs, acid ceramidase (aCDase) converts ceramide into sphingosine and increases the formation of sphingosine-rich intraluminal vesicles (ILVs). Once HSV-1 particles reach MVBs, sphingosine-rich ILVs bind to HSV-1 particles, which restricts fusion with the limiting endosomal membrane and prevents cellular infection. Lack of aCDase in macrophage cultures or in Asah1-/- mice results in replication of HSV-1 and Asah1-/- mice die soon after systemic or intravaginal inoculation. The treatment of macrophages with sphingosine enhancing compounds blocks HSV-1 propagation, suggesting a therapeutic potential of this pathway. In conclusion, aCDase loads ILVs with sphingosine, which prevents HSV-1 capsids from penetrating into the cytosol.
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Affiliation(s)
- Judith Lang
- Institute of Immunology, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany
| | - Patrick Bohn
- Institute of Immunology, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany
| | - Hilal Bhat
- Institute of Immunology, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany
| | - Holger Jastrow
- Institute of Anatomy, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany.,Institut for Experimental Immunology and Imaging, Imaging Center Essen, Electron Microscopy Unit, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany
| | - Bernd Walkenfort
- Institut for Experimental Immunology and Imaging, Imaging Center Essen, Electron Microscopy Unit, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany
| | - Feyza Cansiz
- Institute of Immunology, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany
| | - Julian Fink
- Institute of Organic Chemistry, Julius-Maximilians University of Würzburg, Am Hubland, Würzburg, D-97074, Germany
| | - Michael Bauer
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstr. 190, CH-8057, Zurich, Switzerland
| | - Dominik Olszewski
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstr. 190, CH-8057, Zurich, Switzerland
| | - Ana Ramos-Nascimento
- Institute of Virology, Hannover Medical School, Carl-Neuberg-Str. 1, Hannover, D-30625, Germany
| | - Vikas Duhan
- Institute of Immunology, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany
| | - Sarah-Kim Friedrich
- Institute of Immunology, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany
| | - Katrin Anne Becker
- Institute of Molecular Biology, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany
| | - Adalbert Krawczyk
- Institute for Virology, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany.,Department of Infectious Diseases, University Hospital of Essen, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany
| | - Michael J Edwards
- Department of Surgery, University of Cincinnati, Cincinnati, OH, USA
| | - Andreas Burchert
- Department of Hematology, Oncology and Immunology, University Hospital Giessen and Marburg, Campus Marburg, Baldingerstr., Marburg, D-35043, Germany
| | - Magdalena Huber
- Institute of Medical Microbiology and Hospital Hygiene, Philipps-University Marburg, Hans-Meerwein Str. 2, Marburg, D-35043, Germany
| | - Justa Friebus-Kardash
- Institute of Immunology, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany
| | - Joachim R Göthert
- Department of Hematology, West German Cancer Center, University Hospital of Essen, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany
| | - Cornelia Hardt
- Institute of Immunology, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany
| | - Hans Christian Probst
- Institute of Immunology, University Medical Center Mainz, Langenbeckstr. 1, Mainz, D-55131, Germany
| | - Fabian Schumacher
- Institute of Molecular Biology, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany.,Institute of Nutritional Science, University of Potsdam, Arthur-Scheunert Allee 114-116, Nuthetal, D-14558, Germany
| | - Karl Köhrer
- Biological and Medical Research Center (BMFZ), Heinrich-Heine-University, Universitätsstr. 1, Düsseldorf, D-40225, Germany
| | - Burkhard Kleuser
- Institute of Nutritional Science, University of Potsdam, Arthur-Scheunert Allee 114-116, Nuthetal, D-14558, Germany
| | - Eduard B Babiychuk
- Institute of Anatomy, University of Bern, Baltzerstr. 4, CH-3012, Bern, Switzerland
| | - Beate Sodeik
- Institute of Virology, Hannover Medical School, Carl-Neuberg-Str. 1, Hannover, D-30625, Germany.,Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Carl-Neuberg-Str. 1, Hannover, D-30625, Germany
| | - Jürgen Seibel
- Institute of Organic Chemistry, Julius-Maximilians University of Würzburg, Am Hubland, Würzburg, D-97074, Germany
| | - Urs F Greber
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstr. 190, CH-8057, Zurich, Switzerland
| | - Philipp A Lang
- Department of Molecular Medicine II, Medical Faculty, Heinrich Heine University, Universitätsstr. 1, Düsseldorf, D-40225, Germany
| | - Erich Gulbins
- Institute of Molecular Biology, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany.,Department of Surgery, University of Cincinnati, Cincinnati, OH, USA
| | - Karl S Lang
- Institute of Immunology, University of Duisburg-Essen, Hufelandstr. 55, Essen, D-45147, Germany.
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7
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Carreira AC, Santos TC, Lone MA, Zupančič E, Lloyd-Evans E, de Almeida RFM, Hornemann T, Silva LC. Mammalian sphingoid bases: Biophysical, physiological and pathological properties. Prog Lipid Res 2019:100995. [PMID: 31445071 DOI: 10.1016/j.plipres.2019.100995] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 05/17/2019] [Accepted: 05/20/2019] [Indexed: 12/19/2022]
Abstract
Sphingoid bases encompass a group of long chain amino alcohols which form the essential structure of sphingolipids. Over the last years, these amphiphilic molecules were moving more and more into the focus of biomedical research due to their role as bioactive molecules. In fact, free sphingoid bases interact with specific receptors and target molecules and have been associated with numerous biological and physiological processes. In addition, they can modulate the biophysical properties of biological membranes. Several human diseases are related to pathological changes in the structure and metabolism of sphingoid bases. Yet, the mechanisms underlying their biological and pathophysiological actions remain elusive. Within this review, we aimed to summarize the current knowledge on the biochemical and biophysical properties of the most common sphingoid bases and to discuss their importance in health and disease.
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Affiliation(s)
- A C Carreira
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; Centro de Química e Bioquímica (CQB) e Centro de Química Estrutural (CQE), Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016 Lisboa, Portugal; Sir Martin Evans Building, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - T C Santos
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; Centro de Química-Física Molecular - Institute of Nanoscience and Nanotechnology (CQFM-IN) and IBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal; Institute for Clinical Chemistry, University Hospital Zurich, Switzerland; Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland
| | - M A Lone
- Institute for Clinical Chemistry, University Hospital Zurich, Switzerland; Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland
| | - E Zupančič
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - E Lloyd-Evans
- Sir Martin Evans Building, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - R F M de Almeida
- Centro de Química e Bioquímica (CQB) e Centro de Química Estrutural (CQE), Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016 Lisboa, Portugal
| | - T Hornemann
- Institute for Clinical Chemistry, University Hospital Zurich, Switzerland; Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland
| | - L C Silva
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; Centro de Química-Física Molecular - Institute of Nanoscience and Nanotechnology (CQFM-IN) and IBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.
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8
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Carreira AC, Santos TC, Lone MA, Zupančič E, Lloyd-Evans E, de Almeida RFM, Hornemann T, Silva LC. Mammalian sphingoid bases: Biophysical, physiological and pathological properties. Prog Lipid Res 2019; 75:100988. [PMID: 31132366 DOI: 10.1016/j.plipres.2019.100988] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 05/17/2019] [Accepted: 05/21/2019] [Indexed: 12/11/2022]
Abstract
Sphingoid bases encompass a group of long chain amino alcohols which form the essential structure of sphingolipids. Over the last years, these amphiphilic molecules were moving more and more into the focus of biomedical research due to their role as bioactive molecules. In fact, free sphingoid bases interact with specific receptors and target molecules, and have been associated with numerous biological and physiological processes. In addition, they can modulate the biophysical properties of biological membranes. Several human diseases are related to pathological changes in the structure and metabolism of sphingoid bases. Yet, the mechanisms underlying their biological and pathophysiological actions remain elusive. Within this review, we aimed to summarize the current knowledge on the biochemical and biophysical properties of the most common sphingoid bases and to discuss their importance in health and disease.
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Affiliation(s)
- A C Carreira
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, Lisboa 1649-003, Portugal; Centro de Química e Bioquímica (CQB) e Centro de Química Estrutural (CQE), Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, Lisboa 1749-016, Portugal; Sir Martin Evans Building, School of Biosciences, Cardiff University, Cardiff, UK
| | - T C Santos
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, Lisboa 1649-003, Portugal; Centro de Química-Física Molecular - Institute of Nanoscience and Nanotechnology (CQFM-IN), IBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal; Institute for Clinical Chemistry, University Hospital Zurich, Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland
| | - M A Lone
- Institute for Clinical Chemistry, University Hospital Zurich, Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland
| | - E Zupančič
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, Lisboa 1649-003, Portugal
| | - E Lloyd-Evans
- Sir Martin Evans Building, School of Biosciences, Cardiff University, Cardiff, UK
| | - R F M de Almeida
- Centro de Química e Bioquímica (CQB) e Centro de Química Estrutural (CQE), Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, Lisboa 1749-016, Portugal
| | - T Hornemann
- Institute for Clinical Chemistry, University Hospital Zurich, Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland
| | - L C Silva
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, Lisboa 1649-003, Portugal; Centro de Química-Física Molecular - Institute of Nanoscience and Nanotechnology (CQFM-IN), IBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.
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9
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Gros M, Amigorena S. Regulation of Antigen Export to the Cytosol During Cross-Presentation. Front Immunol 2019; 10:41. [PMID: 30745902 PMCID: PMC6360170 DOI: 10.3389/fimmu.2019.00041] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Accepted: 01/09/2019] [Indexed: 02/02/2023] Open
Abstract
Cross-priming refers to the induction of primary cytotoxic CD8+ T cell responses to antigens that are not expressed in antigen presenting cells (APCs) responsible for T cell priming. Cross-priming is achieved through cross-presentation of exogenous antigens derived from tumors, extracellular pathogens or infected neighboring cells on Major Histocompatibility Complex (MHC) class I molecules. Despite extensive research efforts to understand the intracellular pathways involved in antigen cross-presentation, certain critical steps remain elusive and controversial. Here we review recent advances on antigen cross-presentation, focusing on the mechanisms involved in antigen export to the cytosol, a crucial step of this pathway.
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10
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Manni MM, Tiberti ML, Pagnotta S, Barelli H, Gautier R, Antonny B. Acyl chain asymmetry and polyunsaturation of brain phospholipids facilitate membrane vesiculation without leakage. eLife 2018. [PMID: 29543154 PMCID: PMC5903860 DOI: 10.7554/elife.34394] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Phospholipid membranes form cellular barriers but need to be flexible enough to divide by fission. Phospholipids generally contain a saturated fatty acid (FA) at position sn1 whereas the sn2-FA is saturated, monounsaturated or polyunsaturated. Our understanding of the impact of phospholipid unsaturation on membrane flexibility and fission is fragmentary. Here, we provide a comprehensive view of the effects of the FA profile of phospholipids on membrane vesiculation by dynamin and endophilin. Coupled to simulations, this analysis indicates that: (i) phospholipids with two polyunsaturated FAs make membranes prone to vesiculation but highly permeable; (ii) asymmetric sn1-saturated-sn2-polyunsaturated phospholipids provide a tradeoff between efficient membrane vesiculation and low membrane permeability; (iii) When incorporated into phospholipids, docosahexaenoic acid (DHA; omega-3) makes membranes more deformable than arachidonic acid (omega-6). These results suggest an explanation for the abundance of sn1-saturated-sn2-DHA phospholipids in synaptic membranes and for the importance of the omega-6/omega-3 ratio on neuronal functions. Surrounding each living cell is a membrane that is mainly made of fat molecules called phospholipids. Similar membranes also surround many of the structures inside cells. It is important for life that these membranes are impermeable to many molecules; for example, they do not allow ions to cross them freely. The membranes also need to be flexible and allow cells to form different shapes. Flexible membranes also allow cells to move molecules around and to divide to produce new cells. Each phospholipid includes two long chains of atoms called fatty acids. There are many fatty acids but they are typically grouped into saturated and unsaturated based on their chemical structures. The omega-3 and omega-6 fats are both groups of unsaturated fatty acids that are found in brain cells. Many phospholipids in cell membranes contain one saturated and one unsaturated fatty acid but it is not clear why. By studying fat molecules in the laboratory and combining this with simulations, Manni et al. have now examined the effects of fatty acids on membranes. The investigation showed that phospholipids with both saturated and unsaturated fatty acids strike a balance between impermeable and flexible membranes. More unsaturated fatty acids make more flexible membranes but they are too permeable to be used in cells. The experiments also revealed that omega-3 unsaturated fats aid flexibility more than omega-6. This finding may help to explain why the relative amounts of omega-3 and -6 are so important in the membranes of brain cells. The connection between the fats we eat and the fatty acids in our cells is complex. Yet, findings like these serve to remind us that we need a balanced diet of different fats to keep all our cells healthy.
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Affiliation(s)
- Marco M Manni
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur et CNRS, Valbonne, France.,Instituto Biofisika (UPV/EHU, CSIC), Leioa, Spain
| | - Marion L Tiberti
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur et CNRS, Valbonne, France
| | - Sophie Pagnotta
- Centre Commun de Microscopie Appliquée, Université Côte d'Azur, Nice, France
| | - Hélène Barelli
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur et CNRS, Valbonne, France
| | - Romain Gautier
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur et CNRS, Valbonne, France
| | - Bruno Antonny
- Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur et CNRS, Valbonne, France
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11
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Braun S, Pokorná Š, Šachl R, Hof M, Heerklotz H, Hoernke M. Biomembrane Permeabilization: Statistics of Individual Leakage Events Harmonize the Interpretation of Vesicle Leakage. ACS NANO 2018; 12:813-819. [PMID: 29244483 DOI: 10.1021/acsnano.7b08184] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The mode of action of membrane-active molecules, such as antimicrobial, anticancer, cell penetrating, and fusion peptides and their synthetic mimics, transfection agents, drug permeation enhancers, and biological signaling molecules (e.g., quorum sensing), involves either the general or local destabilization of the target membrane or the formation of defined, rather stable pores. Some effects aim at killing the cell, while others need to be limited in space and time to avoid serious damage. Biological tests reveal translocation of compounds and cell death but do not provide a detailed, mechanistic, and quantitative understanding of the modes of action and their molecular basis. Model membrane studies of membrane leakage have been used for decades to tackle this issue, but their interpretation in terms of biology has remained challenging and often quite limited. Here we compare two recent, powerful protocols to study model membrane leakage: the microscopic detection of dye influx into giant liposomes and time-correlated single photon counting experiments to characterize dye efflux from large unilamellar vesicles. A statistical treatment of both data sets does not only harmonize apparent discrepancies but also makes us aware of principal issues that have been confusing the interpretation of model membrane leakage data so far. Moreover, our study reveals a fundamental difference between nano- and microscale systems that needs to be taken into account when conclusions about microscale objects, such as cells, are drawn from nanoscale models.
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Affiliation(s)
- Stefan Braun
- Department of Pharmaceutical Technology and Biopharmacy, University of Freiburg , 79104 Freiburg im Breisgau, Germany
| | - Šárka Pokorná
- Department of Biophysical Chemistry, J. Heyrovský Institute of Physical Chemistry of the Academy of Sciences of the Czech Republic , 182 23 Prague, Czech Republic
| | - Radek Šachl
- Department of Biophysical Chemistry, J. Heyrovský Institute of Physical Chemistry of the Academy of Sciences of the Czech Republic , 182 23 Prague, Czech Republic
| | - Martin Hof
- Department of Biophysical Chemistry, J. Heyrovský Institute of Physical Chemistry of the Academy of Sciences of the Czech Republic , 182 23 Prague, Czech Republic
| | - Heiko Heerklotz
- Department of Pharmaceutical Technology and Biopharmacy, University of Freiburg , 79104 Freiburg im Breisgau, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg , 79104 Freiburg im Breisgau, Germany
- Leslie Dan Faculty of Pharmacy, University of Toronto , 144 College St., Toronto, Ontario M5S 3M2, Canada
| | - Maria Hoernke
- Department of Pharmaceutical Technology and Biopharmacy, University of Freiburg , 79104 Freiburg im Breisgau, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg , 79104 Freiburg im Breisgau, Germany
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12
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Development of lysosome-mimicking vesicles to study the effect of abnormal accumulation of sphingosine on membrane properties. Sci Rep 2017. [PMID: 28638081 PMCID: PMC5479847 DOI: 10.1038/s41598-017-04125-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Synthetic systems are widely used to unveil the molecular mechanisms of complex cellular events. Artificial membranes are key examples of models employed to address lipid-lipid and lipid-protein interactions. In this work, we developed a new synthetic system that more closely resembles the lysosome – the lysosome-mimicking vesicles (LMVs) – displaying stable acid-to-neutral pH gradient across the membrane. To evaluate the advantages of this synthetic system, we assessed the distinct effects of sphingosine (Sph) accumulation in membrane structure and biophysical properties of standard liposomes (no pH gradient) and in LMVs with lipid composition tuned to mimic physiological- or NPC1-like lysosomes. Ternary 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/Sphingomyelin (SM)/Cholesterol (Chol) mixtures with, respectively, low and high Chol/SM levels were prepared. The effect of Sph on membrane permeability and biophysical properties was evaluated by fluorescence spectroscopy, electrophoretic and dynamic light scattering. The results showed that overall Sph has the ability to cause a shift in vesicle surface charge, increase membrane order and promote a rapid increase in membrane permeability. These effects are enhanced in NPC1- LMVs. The results suggest that lysosomal accumulation of these lipids, as observed under pathological conditions, might significantly affect lysosomal membrane structure and integrity, and therefore contribute to the impairment of cell function.
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13
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Rodriguez-Cuenca S, Pellegrinelli V, Campbell M, Oresic M, Vidal-Puig A. Sphingolipids and glycerophospholipids - The "ying and yang" of lipotoxicity in metabolic diseases. Prog Lipid Res 2017; 66:14-29. [PMID: 28104532 DOI: 10.1016/j.plipres.2017.01.002] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 11/30/2016] [Accepted: 01/05/2017] [Indexed: 12/14/2022]
Abstract
Sphingolipids in general and ceramides in particular, contribute to pathophysiological mechanisms by modifying signalling and metabolic pathways. Here, we present the available evidence for a bidirectional homeostatic crosstalk between sphingolipids and glycerophospholipids, whose dysregulation contributes to lipotoxicity induced metabolic stress. The initial evidence for this crosstalk originates from simulated models designed to investigate the biophysical properties of sphingolipids in plasma membrane representations. In this review, we reinterpret some of the original findings and conceptualise them as a sort of "ying/yang" interaction model of opposed/complementary forces, which is consistent with the current knowledge of lipid homeostasis and pathophysiology. We also propose that the dysregulation of the balance between sphingolipids and glycerophospholipids results in a lipotoxic insult relevant in the pathophysiology of common metabolic diseases, typically characterised by their increased ceramide/sphingosine pools.
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Affiliation(s)
- S Rodriguez-Cuenca
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge. Cambridge, UK.
| | - V Pellegrinelli
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge. Cambridge, UK
| | - M Campbell
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge. Cambridge, UK
| | - M Oresic
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, FI -20520 Turku, Finland
| | - A Vidal-Puig
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge. Cambridge, UK; Wellcome Trust Sanger Institute, Hinxton, UK.
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14
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Kim DI, Suh BC. Differential interaction of β2e with phosphoinositides: A comparative study between β2e and MARCKS. Channels (Austin) 2015; 10:238-46. [PMID: 26650714 DOI: 10.1080/19336950.2015.1124311] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Voltage-gated calcium (CaV) channels are responsible for Ca(2+) influx in excitable cells. As one of the auxiliary subunits, the CaV β subunit plays a pivotal role in the membrane expression and receptor modulation of CaV channels. In particular, the subcellular localization of the β subunit is critical for determining the biophysical properties of CaV channels. Recently, we showed that the β2e isotype is tethered to the plasma membrane. Such a feature of β2e is due to the reversible electrostatic interaction with anionic membrane phospholipids. Here, we further explored the membrane interaction property of β2e by comparing it with that of myristoylated alanine-rich C kinase substrate (MARCKS). First, the charge neutralization of the inner leaf of the plasma membrane induced the translocation of both β2e and MARCKS to the cytosol, while the transient depletion of poly-phosphoinositides (poly-PIs) by translocatable pseudojanin (PJ) systems induced the cytosolic translocation of β2e but not MARCKS. Second, the activation of protein kinase C (PKC) induced the translocation of MARCKS but not β2e. We also found that after the cytosolic translocation of MARCKS by receptor activation, depletion of poly-PIs slowed the recovery of MARCKS to the plasma membrane. Together, our data demonstrate that both β2e and MARCKS bind to the membrane through electrostatic interaction but with different binding affinity, and thus, they are differentially regulated by enzymatic degradation of membrane PIs.
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Affiliation(s)
- Dong-Il Kim
- a Department of Brain and Cognitive Sciences, DGIST , Daegu , Korea
| | - Byung-Chang Suh
- a Department of Brain and Cognitive Sciences, DGIST , Daegu , Korea
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15
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Fröhlich F, Petit C, Kory N, Christiano R, Hannibal-Bach HK, Graham M, Liu X, Ejsing CS, Farese RV, Walther TC. The GARP complex is required for cellular sphingolipid homeostasis. eLife 2015; 4. [PMID: 26357016 PMCID: PMC4600884 DOI: 10.7554/elife.08712] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 09/09/2015] [Indexed: 12/11/2022] Open
Abstract
Sphingolipids are abundant membrane components and important signaling molecules in eukaryotic cells. Their levels and localization are tightly regulated. However, the mechanisms underlying this regulation remain largely unknown. In this study, we identify the Golgi-associated retrograde protein (GARP) complex, which functions in endosome-to-Golgi retrograde vesicular transport, as a critical player in sphingolipid homeostasis. GARP deficiency leads to accumulation of sphingolipid synthesis intermediates, changes in sterol distribution, and lysosomal dysfunction. A GARP complex mutation analogous to a VPS53 allele causing progressive cerebello-cerebral atrophy type 2 (PCCA2) in humans exhibits similar, albeit weaker, phenotypes in yeast, providing mechanistic insights into disease pathogenesis. Inhibition of the first step of de novo sphingolipid synthesis is sufficient to mitigate many of the phenotypes of GARP-deficient yeast or mammalian cells. Together, these data show that GARP is essential for cellular sphingolipid homeostasis and suggest a therapeutic strategy for the treatment of PCCA2. DOI:http://dx.doi.org/10.7554/eLife.08712.001 Every cell is enveloped by a membrane that forms a barrier between the cell and its environment. This membrane contains fat molecules called ‘sphingolipids’, which help to maintain the structure of the membrane and enable it to work correctly. These molecules are also used as signals to send information around the interior of the cell and are required for the cell to grow and divide normally. The levels of sphingolipids in the membrane have to be tightly controlled because any imbalance can cause stress to the cell and can lead to serious diseases. Sphingolipids are made inside the cell and are then sent to a compartment called the Golgi before being delivered to the membrane. To regulate the amount of sphingolipids in the membrane, these molecules are routinely returned to the interior of the cell in small structures called endosomes. From here, they can either be broken down or recycled back to the membrane via the Golgi. A group of proteins known as the Golgi-associated retrograde protein complex (or GARP) is involved in the movement of endosomes from the membrane to the Golgi. People that have a mutation in the gene that encodes GARP suffer from a severe neurodegenerative disease known as ‘progressive cerebello-cerebral atrophy type 2’ (PCCA2) in which brain cells die prematurely. Researchers have assumed that the most important role of GARP is to sort proteins, and that the missorting of proteins leads to PCCA2. Here, Frohlich et al. used a combination of genetic analysis and biochemical techniques to study GARP in yeast cells. The experiments show that GARP is critical for sphingolipid recycling, and that a lack of GARP leads to more sphingolipids being degraded, which results in a build-up of toxic molecules. Frohlich et al. generated yeast cells that have the same mutations in the gene that encodes GARP as those in human patients with PCCA2. These cells grew much slower than normal yeast and were less able to transport sphingolipids from the endosome to the Golgi. Like the yeast cells, human cells in which the gene that encodes GARP was less active also accumulated toxic molecules. Together, these findings suggest that a build-up of toxic fat molecules may be responsible for the symptoms observed in PCCA2 patients. A future challenge is to find out whether this also applies to patients with Alzheimer's disease and other conditions that also affect endosomes. DOI:http://dx.doi.org/10.7554/eLife.08712.002
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Affiliation(s)
- Florian Fröhlich
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, United States.,Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Constance Petit
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, United States.,Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Nora Kory
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, United States.,Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Romain Christiano
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, United States.,Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Hans-Kristian Hannibal-Bach
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Morven Graham
- Center for Cellular and Molecular Imaging, Yale School of Medicine, New Haven, United States
| | - Xinran Liu
- Center for Cellular and Molecular Imaging, Yale School of Medicine, New Haven, United States.,Department of Cell Biology, Yale School of Medicine, New Haven, United States
| | - Christer S Ejsing
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Robert V Farese
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, United States.,Department of Cell Biology, Harvard Medical School, Boston, United States.,Broad Institute, Cambridge, United States
| | - Tobias C Walther
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, United States.,Department of Cell Biology, Harvard Medical School, Boston, United States.,Broad Institute, Cambridge, United States.,Howard Hughes Medical Institute, Harvard T.H. Chan School of Public Health, Boston, United States
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