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Zhu Y, Cho K, Lacin H, Zhu Y, DiPaola JT, Wilson BA, Patti GJ, Skeath JB. Loss of dihydroceramide desaturase drives neurodegeneration by disrupting endoplasmic reticulum and lipid droplet homeostasis in glial cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.01.573836. [PMID: 38260379 PMCID: PMC10802327 DOI: 10.1101/2024.01.01.573836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Dihydroceramide desaturases convert dihydroceramides to ceramides, the precursors of all complex sphingolipids. Reduction of DEGS1 dihydroceramide desaturase function causes pediatric neurodegenerative disorder hypomyelinating leukodystrophy-18 (HLD-18). We discovered that infertile crescent (ifc), the Drosophila DEGS1 homolog, is expressed primarily in glial cells to promote CNS development by guarding against neurodegeneration. Loss of ifc causes massive dihydroceramide accumulation and severe morphological defects in cortex glia, including endoplasmic reticulum (ER) expansion, failure of neuronal ensheathment, and lipid droplet depletion. RNAi knockdown of the upstream ceramide synthase schlank in glia of ifc mutants rescues ER expansion, suggesting dihydroceramide accumulation in the ER drives this phenotype. RNAi knockdown of ifc in glia but not neurons drives neuronal cell death, suggesting that ifc function in glia promotes neuronal survival. Our work identifies glia as the primary site of disease progression in HLD-18 and may inform on juvenile forms of ALS, which also feature elevated dihydroceramide levels.
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Affiliation(s)
- Yuqing Zhu
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St. Louis, MO 63110, USA
| | - Kevin Cho
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
- Center for Mass Spectrometry and Metabolic Tracing, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA
| | - Haluk Lacin
- Division of Biological and Biomedical Systems, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | - Yi Zhu
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St. Louis, MO 63110, USA
| | - Jose T DiPaola
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St. Louis, MO 63110, USA
| | - Beth A Wilson
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St. Louis, MO 63110, USA
| | - Gary J Patti
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
- Center for Mass Spectrometry and Metabolic Tracing, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA
| | - James B Skeath
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St. Louis, MO 63110, USA
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2
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Abimannan T, Parthibane V, Le SH, Vijaykrishna N, Fox SD, Karim B, Kunduri G, Blankenberg D, Andresson T, Bamba T, Acharya U, Acharya JK. Sphingolipid biosynthesis is essential for metabolic rewiring during T H17 cell differentiation. SCIENCE ADVANCES 2024; 10:eadk1045. [PMID: 38657065 PMCID: PMC11042737 DOI: 10.1126/sciadv.adk1045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 03/22/2024] [Indexed: 04/26/2024]
Abstract
T helper 17 (TH17) cells are implicated in autoimmune diseases, and several metabolic processes are shown to be important for their development and function. In this study, we report an essential role for sphingolipids synthesized through the de novo pathway in TH17 cell development. Deficiency of SPTLC1, a major subunit of serine palmitoyl transferase enzyme complex that catalyzes the first and rate-limiting step of de novo sphingolipid synthesis, impaired glycolysis in differentiating TH17 cells by increasing intracellular reactive oxygen species (ROS) through enhancement of nicotinamide adenine dinucleotide phosphate oxidase 2 activity. Increased ROS leads to impaired activation of mammalian target of rapamycin C1 and reduced expression of hypoxia-inducible factor 1-alpha and c-Myc-induced glycolytic genes. SPTLCI deficiency protected mice from developing experimental autoimmune encephalomyelitis and experimental T cell transfer colitis. Our results thus show a critical role for de novo sphingolipid biosynthetic pathway in shaping adaptive immune responses with implications in autoimmune diseases.
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Affiliation(s)
| | - Velayoudame Parthibane
- Cancer and Developmental Biology Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Si-Hung Le
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Nagampalli Vijaykrishna
- Genomic Medicine Institute and Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Stephen D. Fox
- Mass Spectrometry Group, National Cancer Institute, Frederick, MD, USA
| | - Baktiar Karim
- Molecular Histopathology Laboratory, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Govind Kunduri
- Cancer and Developmental Biology Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Daniel Blankenberg
- Genomic Medicine Institute and Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | - Takeshi Bamba
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Usha Acharya
- Cancer and Developmental Biology Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Jairaj K. Acharya
- Cancer and Developmental Biology Laboratory, National Cancer Institute, Frederick, MD, USA
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3
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Héja L, Simon Á, Kardos J. Simulation of gap junction formation reveals critical role of Cys disulfide redox state in connexin hemichannel docking. Cell Commun Signal 2024; 22:185. [PMID: 38500186 PMCID: PMC10949817 DOI: 10.1186/s12964-023-01439-z] [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: 08/11/2023] [Accepted: 12/12/2023] [Indexed: 03/20/2024] Open
Abstract
Video Abstract.
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Affiliation(s)
- László Héja
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, 1117, Budapest, Hungary.
| | - Ágnes Simon
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, 1117, Budapest, Hungary
| | - Julianna Kardos
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, 1117, Budapest, Hungary
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4
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Corty MM, Coutinho-Budd J. Drosophila glia take shape to sculpt the nervous system. Curr Opin Neurobiol 2023; 79:102689. [PMID: 36822142 PMCID: PMC10023329 DOI: 10.1016/j.conb.2023.102689] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/19/2022] [Accepted: 01/10/2023] [Indexed: 02/23/2023]
Abstract
The importance of glial cells has become increasingly apparent over the past 20 years, yet compared to neurons we still know relatively little about these essential cells. Most critical glial cell functions are conserved in Drosophila glia, often using the same key molecular players as their vertebrate counterparts. The relative simplicity of the Drosophila nervous system, combined with a vast array of powerful genetic tools, allows us to further dissect the molecular composition and functional roles of glia in ways that would be much more cumbersome or not possible in higher vertebrate systems. Importantly, Drosophila genetics allow for in vivo manipulation, and their transparent body wall enables in vivo imaging of glia in intact animals throughout early development. Here we discuss recent advances in Drosophila glial development detailing how these cells take on their mature morphologies and interact with neurons to perform their important functional roles in the nervous system.
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Affiliation(s)
- Megan M Corty
- Vollum Institute, Oregon Health & Science University, Portland, OR, USA. https://twitter.com/@megancphd
| | - Jaeda Coutinho-Budd
- Department of Neuroscience, University of Virginia, Charlottesville, VA, USA.
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5
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Vaughen JP, Theisen E, Clandinin TR. From seconds to days: Neural plasticity viewed through a lipid lens. Curr Opin Neurobiol 2023; 80:102702. [PMID: 36965206 DOI: 10.1016/j.conb.2023.102702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 01/31/2023] [Accepted: 02/16/2023] [Indexed: 03/27/2023]
Abstract
Many adult neurons are dynamically remodeled across timescales ranging from the rapid addition and removal of specific synaptic connections, to largescale structural plasticity events that reconfigure circuits over hours, days, and months. Membrane lipids, including brain-enriched sphingolipids, play crucial roles in these processes. In this review, we summarize progress at the intersection of neuronal activity, lipids, and structural remodeling. We highlight how brain activity modulates lipid metabolism to enable adaptive structural plasticity, and showcase glia as key players in membrane remodeling. These studies reveal that lipids act as critical signaling molecules that instruct the dynamic architecture of the brain.
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Affiliation(s)
- John P Vaughen
- Department of Neurobiology, Stanford University, Stanford, CA, 94305, United States; Department of Developmental Biology, Stanford University, Stanford, CA, 94305, United States. https://twitter.com/gliaful
| | - Emma Theisen
- Department of Neurobiology, Stanford University, Stanford, CA, 94305, United States. https://twitter.com/emmaktheisen
| | - Thomas R Clandinin
- Department of Neurobiology, Stanford University, Stanford, CA, 94305, United States.
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6
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SIK3 and Wnk converge on Fray to regulate glial K+ buffering and seizure susceptibility. PLoS Genet 2023; 19:e1010581. [PMID: 36626385 PMCID: PMC9870106 DOI: 10.1371/journal.pgen.1010581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 01/23/2023] [Accepted: 12/19/2022] [Indexed: 01/11/2023] Open
Abstract
Glial cells play a critical role in maintaining homeostatic ion concentration gradients. Salt-inducible kinase 3 (SIK3) regulates a gene expression program that controls K+ buffering in glia, and upregulation of this pathway suppresses seizure behavior in the eag, Shaker hyperexcitability mutant. Here we show that boosting the glial SIK3 K+ buffering pathway suppresses seizures in three additional molecularly diverse hyperexcitable mutants, highlighting the therapeutic potential of upregulating glial K+ buffering. We then explore additional mechanisms regulating glial K+ buffering. Fray, a transcriptional target of the SIK3 K+ buffering program, is a kinase that promotes K+ uptake by activating the Na+/K+/Cl- co-transporter, Ncc69. We show that the Wnk kinase phosphorylates Fray in Drosophila glia and that this activity is required to promote K+ buffering. This identifies Fray as a convergence point between the SIK3-dependent transcriptional program and Wnk-dependent post-translational regulation. Bypassing both regulatory mechanisms via overexpression of a constitutively active Fray in glia is sufficient to robustly suppress seizure behavior in multiple Drosophila models of hyperexcitability. Finally, we identify cortex glia as a critical cell type for regulation of seizure susceptibility, as boosting K+ buffering via expression of activated Fray exclusively in these cells is sufficient to suppress seizure behavior. These findings highlight Fray as a key convergence point for distinct K+ buffering regulatory mechanisms and cortex glia as an important locus for control of neuronal excitability.
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Fischer FP, Karge RA, Weber YG, Koch H, Wolking S, Voigt A. Drosophila melanogaster as a versatile model organism to study genetic epilepsies: An overview. Front Mol Neurosci 2023; 16:1116000. [PMID: 36873106 PMCID: PMC9978166 DOI: 10.3389/fnmol.2023.1116000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 01/23/2023] [Indexed: 02/18/2023] Open
Abstract
Epilepsy is one of the most prevalent neurological disorders, affecting more than 45 million people worldwide. Recent advances in genetic techniques, such as next-generation sequencing, have driven genetic discovery and increased our understanding of the molecular and cellular mechanisms behind many epilepsy syndromes. These insights prompt the development of personalized therapies tailored to the genetic characteristics of an individual patient. However, the surging number of novel genetic variants renders the interpretation of pathogenetic consequences and of potential therapeutic implications ever more challenging. Model organisms can help explore these aspects in vivo. In the last decades, rodent models have significantly contributed to our understanding of genetic epilepsies but their establishment is laborious, expensive, and time-consuming. Additional model organisms to investigate disease variants on a large scale would be desirable. The fruit fly Drosophila melanogaster has been used as a model organism in epilepsy research since the discovery of "bang-sensitive" mutants more than half a century ago. These flies respond to mechanical stimulation, such as a brief vortex, with stereotypic seizures and paralysis. Furthermore, the identification of seizure-suppressor mutations allows to pinpoint novel therapeutic targets. Gene editing techniques, such as CRISPR/Cas9, are a convenient way to generate flies carrying disease-associated variants. These flies can be screened for phenotypic and behavioral abnormalities, shifting of seizure thresholds, and response to anti-seizure medications and other substances. Moreover, modification of neuronal activity and seizure induction can be achieved using optogenetic tools. In combination with calcium and fluorescent imaging, functional alterations caused by mutations in epilepsy genes can be traced. Here, we review Drosophila as a versatile model organism to study genetic epilepsies, especially as 81% of human epilepsy genes have an orthologous gene in Drosophila. Furthermore, we discuss newly established analysis techniques that might be used to further unravel the pathophysiological aspects of genetic epilepsies.
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Affiliation(s)
- Florian P Fischer
- Department of Epileptology and Neurology, RWTH Aachen University, Aachen, Germany
| | - Robin A Karge
- Department of Epileptology and Neurology, RWTH Aachen University, Aachen, Germany
| | - Yvonne G Weber
- Department of Epileptology and Neurology, RWTH Aachen University, Aachen, Germany.,Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Henner Koch
- Department of Epileptology and Neurology, RWTH Aachen University, Aachen, Germany
| | - Stefan Wolking
- Department of Epileptology and Neurology, RWTH Aachen University, Aachen, Germany
| | - Aaron Voigt
- Department of Neurology, RWTH Aachen University, Aachen, Germany.,JARA-BRAIN Institute Molecular Neuroscience and Neuroimaging, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
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8
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Lipid Polarization during Cytokinesis. Cells 2022; 11:cells11243977. [PMID: 36552741 PMCID: PMC9776629 DOI: 10.3390/cells11243977] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 12/01/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022] Open
Abstract
The plasma membrane of eukaryotic cells is composed of a large number of lipid species that are laterally segregated into functional domains as well as asymmetrically distributed between the outer and inner leaflets. Additionally, the spatial distribution and organization of these lipids dramatically change in response to various cellular states, such as cell division, differentiation, and apoptosis. Division of one cell into two daughter cells is one of the most fundamental requirements for the sustenance of growth in all living organisms. The successful completion of cytokinesis, the final stage of cell division, is critically dependent on the spatial distribution and organization of specific lipids. In this review, we discuss the properties of various lipid species associated with cytokinesis and the mechanisms involved in their polarization, including forward trafficking, endocytic recycling, local synthesis, and cortical flow models. The differences in lipid species requirements and distribution in mitotic vs. male meiotic cells will be discussed. We will concentrate on sphingolipids and phosphatidylinositols because their transbilayer organization and movement may be linked via the cytoskeleton and thus critically regulate various steps of cytokinesis.
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9
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Vaughen JP, Theisen E, Rivas-Serna IM, Berger AB, Kalakuntla P, Anreiter I, Mazurak VC, Rodriguez TP, Mast JD, Hartl T, Perlstein EO, Reimer RJ, Clandinin MT, Clandinin TR. Glial control of sphingolipid levels sculpts diurnal remodeling in a circadian circuit. Neuron 2022; 110:3186-3205.e7. [PMID: 35961319 PMCID: PMC10868424 DOI: 10.1016/j.neuron.2022.07.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 05/21/2022] [Accepted: 07/14/2022] [Indexed: 11/19/2022]
Abstract
Structural plasticity in the brain often necessitates dramatic remodeling of neuronal processes, with attendant reorganization of the cytoskeleton and membranes. Although cytoskeletal restructuring has been studied extensively, how lipids might orchestrate structural plasticity remains unclear. We show that specific glial cells in Drosophila produce glucocerebrosidase (GBA) to locally catabolize sphingolipids. Sphingolipid accumulation drives lysosomal dysfunction, causing gba1b mutants to harbor protein aggregates that cycle across circadian time and are regulated by neural activity, the circadian clock, and sleep. Although the vast majority of membrane lipids are stable across the day, a specific subset that is highly enriched in sphingolipids cycles daily in a gba1b-dependent fashion. Remarkably, both sphingolipid biosynthesis and degradation are required for the diurnal remodeling of circadian clock neurites, which grow and shrink across the day. Thus, dynamic sphingolipid regulation by glia enables diurnal circuit remodeling and proper circadian behavior.
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Affiliation(s)
- John P Vaughen
- Department of Neurobiology, Stanford University, Stanford, CA 94305, USA; Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA
| | - Emma Theisen
- Department of Neurobiology, Stanford University, Stanford, CA 94305, USA
| | - Irma Magaly Rivas-Serna
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Andrew B Berger
- Department of Neurobiology, Stanford University, Stanford, CA 94305, USA
| | - Prateek Kalakuntla
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA
| | - Ina Anreiter
- Department of Neurobiology, Stanford University, Stanford, CA 94305, USA
| | - Vera C Mazurak
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | | | - Joshua D Mast
- Perlara PBC, 2625 Alcatraz Ave #435, Berkeley, CA 94705, USA
| | - Tom Hartl
- Perlara PBC, 2625 Alcatraz Ave #435, Berkeley, CA 94705, USA
| | | | - Richard J Reimer
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA
| | - M Thomas Clandinin
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Thomas R Clandinin
- Department of Neurobiology, Stanford University, Stanford, CA 94305, USA.
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Myren‐Svelstad S, Jamali A, Ophus SS, D'gama PP, Ostenrath AM, Mutlu AK, Hoffshagen HH, Hotz AL, Neuhauss SCF, Jurisch‐Yaksi N, Yaksi E. Elevated photic response is followed by a rapid decay and depressed state in ictogenic networks. Epilepsia 2022; 63:2543-2560. [PMID: 36222083 PMCID: PMC9804334 DOI: 10.1111/epi.17380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 07/27/2022] [Accepted: 07/27/2022] [Indexed: 01/05/2023]
Abstract
OBJECTIVE The switch between nonseizure and seizure states involves profound alterations in network excitability and synchrony. In this study, we aimed to identify and compare features of neural excitability and dynamics across multiple zebrafish seizure and epilepsy models. METHODS Inspired by video-electroencephalographic recordings in patients, we developed a framework to study spontaneous and photically evoked neural and locomotor activity in zebrafish larvae, by combining high-throughput behavioral tracking and whole-brain in vivo two-photon calcium imaging. RESULTS Our setup allowed us to dissect behavioral and physiological features that are divergent or convergent across multiple models. We observed that spontaneous locomotor and neural activity exhibit great diversity across models. Nonetheless, during photic stimulation, hyperexcitability and rapid response dynamics were well conserved across multiple models, highlighting the reliability of photically evoked activity for high-throughput assays. Intriguingly, in several models, we observed that the initial elevated photic response is often followed by rapid decay of neural activity and a prominent depressed state. Elevated photic response and following depressed state in seizure-prone networks are significantly reduced by the antiseizure medication valproic acid. Finally, rapid decay and depression of neural activity following photic stimulation temporally overlap with slow recruitment of astroglial calcium signals that are enhanced in seizure-prone networks. SIGNIFICANCE We argue that fast decay of neural activity and depressed states following photic response are likely due to homeostatic mechanisms triggered by excessive neural activity. An improved understanding of the interplay between elevated and depressed excitability states might suggest tailored epilepsy therapies.
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Affiliation(s)
- Sverre Myren‐Svelstad
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway,Department of Neuromedicine and Movement Science, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway,Department of Neurology and Clinical NeurophysiologySt Olav's University HospitalTrondheimNorway
| | - Ahmed Jamali
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway,Department of Neuromedicine and Movement Science, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway,Department of Neurology and Clinical NeurophysiologySt Olav's University HospitalTrondheimNorway
| | - Sunniva S. Ophus
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway
| | - Percival P. D'gama
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway,Department of Clinical and Molecular Medicine, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway
| | - Anna M. Ostenrath
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway
| | - Aytac Kadir Mutlu
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway
| | - Helene Homme Hoffshagen
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway
| | - Adriana L. Hotz
- Department of Molecular Life SciencesUniversity of ZürichZürichSwitzerland
| | | | - Nathalie Jurisch‐Yaksi
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway,Department of Neurology and Clinical NeurophysiologySt Olav's University HospitalTrondheimNorway,Department of Clinical and Molecular Medicine, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway
| | - Emre Yaksi
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway,Koç University Research Center for Translational Medicine, Department of NeurologyKoç University School of MedicineIstanbulTurkey
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11
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Kunduri G, Le SH, Baena V, Vijaykrishna N, Harned A, Nagashima K, Blankenberg D, Yoshihiro I, Narayan K, Bamba T, Acharya U, Acharya JK. Delivery of ceramide phosphoethanolamine lipids to the cleavage furrow through the endocytic pathway is essential for male meiotic cytokinesis. PLoS Biol 2022; 20:e3001599. [PMID: 36170207 PMCID: PMC9550178 DOI: 10.1371/journal.pbio.3001599] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 10/10/2022] [Accepted: 08/02/2022] [Indexed: 11/18/2022] Open
Abstract
Cell division, wherein 1 cell divides into 2 daughter cells, is fundamental to all living organisms. Cytokinesis, the final step in cell division, begins with the formation of an actomyosin contractile ring, positioned midway between the segregated chromosomes. Constriction of the ring with concomitant membrane deposition in a specified spatiotemporal manner generates a cleavage furrow that physically separates the cytoplasm. Unique lipids with specific biophysical properties have been shown to localize to intercellular bridges (also called midbody) connecting the 2 dividing cells; however, their biological roles and delivery mechanisms remain largely unknown. In this study, we show that ceramide phosphoethanolamine (CPE), the structural analog of sphingomyelin, has unique acyl chain anchors in Drosophila spermatocytes and is essential for meiotic cytokinesis. The head group of CPE is also important for spermatogenesis. We find that aberrant central spindle and contractile ring behavior but not mislocalization of phosphatidylinositol phosphates (PIPs) at the plasma membrane is responsible for the male meiotic cytokinesis defect in CPE-deficient animals. Further, we demonstrate the enrichment of CPE in multivesicular bodies marked by Rab7, which in turn localize to cleavage furrow. Volume electron microscopy analysis using correlative light and focused ion beam scanning electron microscopy shows that CPE-enriched Rab7 positive endosomes are juxtaposed on contractile ring material. Correlative light and transmission electron microscopy reveal Rab7 positive endosomes as a multivesicular body-like organelle that releases its intraluminal vesicles in the vicinity of ingressing furrows. Genetic ablation of Rab7 or Rab35 or expression of dominant negative Rab11 results in significant meiotic cytokinesis defects. Further, we show that Rab11 function is required for localization of CPE positive endosomes to the cleavage furrow. Our results imply that endosomal delivery of CPE to ingressing membranes is crucial for meiotic cytokinesis.
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Affiliation(s)
- Govind Kunduri
- Cancer and Developmental Biology Laboratory, National Cancer Institute, Frederick, Maryland, United States of America
| | - Si-Hung Le
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Valentina Baena
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Nagampalli Vijaykrishna
- Genomic Medicine Institute and Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Adam Harned
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Kunio Nagashima
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Daniel Blankenberg
- Genomic Medicine Institute and Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Izumi Yoshihiro
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Kedar Narayan
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Takeshi Bamba
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Usha Acharya
- Cancer and Developmental Biology Laboratory, National Cancer Institute, Frederick, Maryland, United States of America
| | - Jairaj K. Acharya
- Cancer and Developmental Biology Laboratory, National Cancer Institute, Frederick, Maryland, United States of America
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12
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Chen X, Li J, Gao Z, Yang Y, Kuang W, Dong Y, Chua GH, Huang X, Jiang B, Tian H, Wang Y, Huang X, Li Y, Lam SM, Shui G. Endogenous ceramide phosphoethanolamine modulates circadian rhythm via neural-glial coupling in Drosophila. Natl Sci Rev 2022; 9:nwac148. [PMID: 36713590 PMCID: PMC9875363 DOI: 10.1093/nsr/nwac148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 06/08/2022] [Accepted: 07/13/2022] [Indexed: 02/01/2023] Open
Abstract
While endogenous lipids are known to exhibit rhythmic oscillations, less is known about how specific lipids modulate circadian behavior. Through a series of loss-of-function and gain-of-function experiments on ceramide phosphoethanolamine (CPE) synthase of Drosophila, we demonstrated that pan-glial-specific deficiency in membrane CPE, the structural analog of mammalian sphingomyelin (SM), leads to arrhythmic locomotor behavior and shortens lifespan, while the reverse is true for increasing CPE. Comparative proteomics uncovered dysregulated synaptic glutamate utilization and transport in CPE-deficient flies. An extensive genetic screen was conducted to verify the role of differentially expressed proteins in circadian regulation. Arrhythmic locomotion under cpes1 mutant background was rescued only by restoring endogenous CPE or SM through expressing their respective synthases. Our results underscore the essential role of CPE in maintaining synaptic glutamate homeostasis and modulating circadian behavior in Drosophila. The findings suggest that region-specific elevations of functional membrane lipids can benefit circadian regulation.
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Affiliation(s)
| | | | - Zhongbao Gao
- University of Chinese Academy of Sciences, Beijing 100049, China,State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yang Yang
- University of Chinese Academy of Sciences, Beijing 100049, China,State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Wenqing Kuang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing100101, China,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yue Dong
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing100101, China,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Gek Huey Chua
- LipidALL Technologies Company Limited, Changzhou213022, China
| | - Xiahe Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing100101, China
| | - Binhua Jiang
- LipidALL Technologies Company Limited, Changzhou213022, China
| | - He Tian
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing100101, China
| | - Yingchun Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing100101, China,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xun Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing100101, China,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Li
- University of Chinese Academy of Sciences, Beijing 100049, China,State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
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13
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Lazarsfeld J, Rodriguez J, Erden M, Liu Y, Cowen LJ. Majority Vote Cascading: A Semi-Supervised Framework for Improving Protein Function Prediction. IEEE/ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS 2022; 19:1933-1945. [PMID: 33591921 DOI: 10.1109/tcbb.2021.3059812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A method to improve protein function prediction for sparsely annotated PPI networks is introduced. The method extends the DSD majority vote algorithm introduced by Cao et al. to give confidence scores on predicted labels and to use predictions of high confidence to predict the labels of other nodes in subsequent rounds. We call this a majority vote cascade. Several cascade variants are tested in a stringent cross-validation experiment on PPI networks from S. cerevisiae and D. melanogaster, and we show that for many different settings with several alternative confidence functions, cascading improves the accuracy of the predictions. A list of the most confident new label predictions in the two networks is also reported. Code and networks for the cross-validation experiments appear at http://bcb.cs.tufts.edu/cascade.
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14
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Fisher RS, Acharya JN, Baumer FM, French JA, Parisi P, Solodar JH, Szaflarski JP, Thio LL, Tolchin B, Wilkins AJ, Kasteleijn-Nolst Trenité D. Visually sensitive seizures: An updated review by the Epilepsy Foundation. Epilepsia 2022; 63:739-768. [PMID: 35132632 DOI: 10.1111/epi.17175] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 12/19/2022]
Abstract
Light flashes, patterns, or color changes can provoke seizures in up to 1 in 4000 persons. Prevalence may be higher because of selection bias. The Epilepsy Foundation reviewed light-induced seizures in 2005. Since then, images on social media, virtual reality, three-dimensional (3D) movies, and the Internet have proliferated. Hundreds of studies have explored the mechanisms and presentations of photosensitive seizures, justifying an updated review. This literature summary derives from a nonsystematic literature review via PubMed using the terms "photosensitive" and "epilepsy." The photoparoxysmal response (PPR) is an electroencephalography (EEG) phenomenon, and photosensitive seizures (PS) are seizures provoked by visual stimulation. Photosensitivity is more common in the young and in specific forms of generalized epilepsy. PS can coexist with spontaneous seizures. PS are hereditable and linked to recently identified genes. Brain imaging usually is normal, but special studies imaging white matter tracts demonstrate abnormal connectivity. Occipital cortex and connected regions are hyperexcitable in subjects with light-provoked seizures. Mechanisms remain unclear. Video games, social media clips, occasional movies, and natural stimuli can provoke PS. Virtual reality and 3D images so far appear benign unless they contain specific provocative content, for example, flashes. Images with flashes brighter than 20 candelas/m2 at 3-60 (particularly 15-20) Hz occupying at least 10 to 25% of the visual field are a risk, as are red color flashes or oscillating stripes. Equipment to assay for these characteristics is probably underutilized. Prevention of seizures includes avoiding provocative stimuli, covering one eye, wearing dark glasses, sitting at least two meters from screens, reducing contrast, and taking certain antiseizure drugs. Measurement of PPR suppression in a photosensitivity model can screen putative antiseizure drugs. Some countries regulate media to reduce risk. Visually-induced seizures remain significant public health hazards so they warrant ongoing scientific and regulatory efforts and public education.
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Affiliation(s)
- Robert S Fisher
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California, USA
| | - Jayant N Acharya
- Department of Neurology, Penn State Health, Hershey, Pennsylvania, USA
| | - Fiona Mitchell Baumer
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California, USA
| | - Jacqueline A French
- NYU Comprehensive Epilepsy Center, Epilepsy Foundation, New York, New York, USA
| | - Pasquale Parisi
- Department of Neuroscience, Mental Health, and Sensory Organs, Sapienza University, Rome, Italy
| | - Jessica H Solodar
- American Medical Writers Association-New England Chapter, Boston, Massachusetts, USA
| | - Jerzy P Szaflarski
- Department of Neurology, Neurobiology and Neurosurgery, University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, USA
| | - Liu Lin Thio
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Benjamin Tolchin
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut, USA
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15
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Ecovoiu AA, Ratiu AC, Micheu MM, Chifiriuc MC. Inter-Species Rescue of Mutant Phenotype—The Standard for Genetic Analysis of Human Genetic Disorders in Drosophila melanogaster Model. Int J Mol Sci 2022; 23:ijms23052613. [PMID: 35269756 PMCID: PMC8909942 DOI: 10.3390/ijms23052613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 02/23/2022] [Accepted: 02/24/2022] [Indexed: 11/16/2022] Open
Abstract
Drosophila melanogaster (the fruit fly) is arguably a superstar of genetics, an astonishing versatile experimental model which fueled no less than six Nobel prizes in medicine. Nowadays, an evolving research endeavor is to simulate and investigate human genetic diseases in the powerful D. melanogaster platform. Such a translational experimental strategy is expected to allow scientists not only to understand the molecular mechanisms of the respective disorders but also to alleviate or even cure them. In this regard, functional gene orthology should be initially confirmed in vivo by transferring human or vertebrate orthologous transgenes in specific mutant backgrounds of D. melanogaster. If such a transgene rescues, at least partially, the mutant phenotype, then it qualifies as a strong candidate for modeling the respective genetic disorder in the fruit fly. Herein, we review various examples of inter-species rescue of relevant mutant phenotypes of the fruit fly and discuss how these results recommend several human genes as candidates to study and validate genetic variants associated with human diseases. We also consider that a wider implementation of this evolutionist exploratory approach as a standard for the medicine of genetic disorders would allow this particular field of human health to advance at a faster pace.
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Affiliation(s)
- Alexandru Al. Ecovoiu
- Department of Genetics, Faculty of Biology, University of Bucharest, 060101 Bucharest, Romania;
| | - Attila Cristian Ratiu
- Department of Genetics, Faculty of Biology, University of Bucharest, 060101 Bucharest, Romania;
- Correspondence: ; Tel.: +40-722250366
| | - Miruna Mihaela Micheu
- Department of Cardiology, Clinical Emergency Hospital of Bucharest, 014461 Bucharest, Romania;
| | - Mariana Carmen Chifiriuc
- The Research Institute of the University of Bucharest and Faculty of Biology, University of Bucharest, 050095 Bucharest, Romania;
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16
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Arkov AL. Looking at the Pretty "Phase" of Membraneless Organelles: A View From Drosophila Glia. Front Cell Dev Biol 2022; 10:801953. [PMID: 35198559 PMCID: PMC8859445 DOI: 10.3389/fcell.2022.801953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 01/19/2022] [Indexed: 11/13/2022] Open
Abstract
Membraneless granules assemble in different cell types and cellular loci and are the focus of intense research due to their fundamental importance for cellular organization. These dynamic organelles are commonly assembled from RNA and protein components and exhibit soft matter characteristics of molecular condensates currently characterized with biophysical approaches and super-resolution microscopy imaging. In addition, research on the molecular mechanisms of the RNA-protein granules assembly provided insights into the formation of abnormal granules and molecular aggregates, which takes place during many neurodegenerative disorders including Parkinson's diseases (PD), Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), and frontotemporal dementia (FTD). While these disorders are associated with formation of abnormal granules, membraneless organelles are normally assembled in neurons and contribute to translational control and affect stability of neuronal RNAs. More recently, a new subtype of membraneless granules was identified in Drosophila glia (glial granules). Interestingly, glial granules were found to contain proteins which are the principal components of the membraneless granules in germ cells (germ granules), indicating some similarity in the functional assembly of these structures in glia and germline. This mini review highlights recent research on glial granules in the context of other membraneless organelles, including their assembly mechanisms and potential functions in the nervous system.
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Affiliation(s)
- Alexey L Arkov
- Department of Biological Sciences, Murray State University, Murray, KY, United States
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17
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Untargeted Metabolomics Reveals a Complex Impact on Different Metabolic Pathways in Scallop Mimachlamys varia (Linnaeus, 1758) after Short-Term Exposure to Copper at Environmental Dose. Metabolites 2021; 11:metabo11120862. [PMID: 34940620 PMCID: PMC8703567 DOI: 10.3390/metabo11120862] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/08/2021] [Accepted: 12/09/2021] [Indexed: 12/15/2022] Open
Abstract
Ports are a good example of how coastal environments, gathering a set of diverse ecosystems, are subjected to pollution factors coming from human activities both on land and at sea. Among them, trace element as copper represents a major factor. Abundant in port ecosystem, copper is transported by runoff water and results from diverse port features (corrosion of structures, fuel, anti-fouling products, etc.). The variegated scallop Mimachlamys varia is common in the Atlantic port areas and is likely to be directly influenced by copper pollution, due to its sessile and filtering lifestyle. Thus, the aim of the present study is to investigate the disruption of the variegated scallop metabolism, under a short exposure (48 h) to a copper concentration frequently encountered in the waters of the largest marina in Europe (82 μg/L). For this, we chose a non-targeted metabolomic approach using ultra-high performance liquid chromatography coupled to high resolution mass spectrometry (UHPLC-HRMS), offering a high level of sensitivity and allowing the study without a priori of the entire metabolome. We described 28 metabolites clearly modulated by copper. They reflected the action of copper on several biological functions such as osmoregulation, oxidative stress, reproduction and energy metabolism.
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18
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Glial glucose fuels the neuronal pentose phosphate pathway for long-term memory. Cell Rep 2021; 36:109620. [PMID: 34433052 PMCID: PMC8411112 DOI: 10.1016/j.celrep.2021.109620] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 07/22/2021] [Accepted: 08/05/2021] [Indexed: 01/10/2023] Open
Abstract
Brain function relies almost solely on glucose as an energy substrate. The main model of brain metabolism proposes that glucose is taken up and converted into lactate by astrocytes to fuel the energy-demanding neuronal activity underlying plasticity and memory. Whether direct neuronal glucose uptake is required for memory formation remains elusive. We uncover, in Drosophila, a mechanism of glucose shuttling to neurons from cortex glia, an exclusively perisomatic glial subtype, upon formation of olfactory long-term memory (LTM). In vivo imaging reveals that, downstream of cholinergic activation of cortex glia, autocrine insulin signaling increases glucose concentration in glia. Glucose is then transferred from glia to the neuronal somata in the olfactory memory center to fuel the pentose phosphate pathway and allow LTM formation. In contrast, our results indicate that the increase in neuronal glucose metabolism, although crucial for LTM formation, is not routed to glycolysis. Neuronal glucose metabolism is increased upon long-term memory formation Glial cells shuttle glucose to neurons following insulin signaling activation Glucose fuels the neuronal pentose phosphate pathway
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19
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Johnson A, Grove RA, Madhavan D, Boone CHT, Braga C, Kyllo H, Samson K, Simeone K, Simeone T, Helikar T, Hanson CK, Adamec J. Changes in lipid profiles of epileptic mouse model. Metabolomics 2020; 16:106. [PMID: 33021695 PMCID: PMC10614666 DOI: 10.1007/s11306-020-01729-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Accepted: 09/23/2020] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Approximately 1% of the world's population is impacted by epilepsy, a chronic neurological disorder characterized by seizures. One-third of epileptic patients are resistant to AEDs, or have medically refractory epilepsy (MRE). One non-invasive treatment that exists for MRE includes the ketogenic diet, a high-fat, low-carbohydrate diet. Despite the KD's success in seizure attenuation, it has a few risks and its mechanisms remain poorly understood. The KD has been shown to improve metabolism and mitochondrial function in epileptic phenotypes. Potassium channels have implications in epileptic conditions as they have dual roles as metabolic sensors and control neuronal excitation. OBJECTIVES The goal of this study was to explore changes in the lipidome in hippocampal and cortical tissue from Kv1.1-KO model of epilepsy. METHODS FT-ICR/MS analysis was utilized to examine nonpolar metabolome of cortical and hippocampal tissue isolated from a Kv1.1 channel knockout mouse model of epilepsy (n = 5) and wild-type mice (n = 5). RESULTS Distinct metabolic profiles were observed, significant (p < 0.05) features in hippocampus often being upregulated (FC ≥ 2) and the cortex being downregulated (FC ≤ 0.5). Pathway enrichment analysis shows lipid biosynthesis was affected. Partition ratio analysis revealed that the ratio of most metabolites tended to be increased in Kv1.1-/-. Metabolites in hippocampal tissue were commonly upregulated, suggesting seizure initiation in the hippocampus. Aberrant mitochondrial function is implicated by the upregulation of cardiolipin, a common component in the mitochondrial membrane. CONCLUSION Generally, our study finds that the lipidome is changed in the hippocampus and cortex in response to Kv1.1-KO indicating changes in membrane structural integrity and synaptic transmission.
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Affiliation(s)
- Alicia Johnson
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Ryan A Grove
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Deepak Madhavan
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Cory H T Boone
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Camila Braga
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Hannah Kyllo
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Kaeli Samson
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Kristina Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Timothy Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Tomas Helikar
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Corrine K Hanson
- College of Allied Health Professions, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Jiri Adamec
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
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20
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Sptlc1 is essential for myeloid differentiation and hematopoietic homeostasis. Blood Adv 2020; 3:3635-3649. [PMID: 31751474 DOI: 10.1182/bloodadvances.2019000729] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 10/07/2019] [Indexed: 12/12/2022] Open
Abstract
Serine palmitoyltransferase (SPT) long-chain base subunit 1 (SPTLC1) is 1 of the 2 main catalytic subunits of the SPT complex, which catalyzes the first and rate-limiting step of sphingolipid biosynthesis. Here, we show that Sptlc1 deletion in adult bone marrow (BM) cells results in defective myeloid differentiation. In chimeric mice from noncompetitive BM transplant assays, there was an expansion of the Lin- c-Kit+ Sca-1+ compartment due to increased multipotent progenitor production, but myeloid differentiation was severely compromised. We also show that defective biogenesis of sphingolipids in the endoplasmic reticulum (ER) leads to ER stress that affects myeloid differentiation. Furthermore, we demonstrate that transient accumulation of fatty acid, a substrate for sphingolipid biosynthesis, could be partially responsible for the ER stress. Independently, we find that ER stress in general, such as that induced by the chemical thapsigargin or the fatty acid palmitic acid, compromises myeloid differentiation in culture. These results identify perturbed sphingolipid metabolism as a source of ER stress, which may produce diverse pathological effects related to differential cell-type sensitivity.
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21
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Wrapping axons in mammals and Drosophila: Different lipids, same principle. Biochimie 2020; 178:39-48. [PMID: 32800899 DOI: 10.1016/j.biochi.2020.08.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/31/2020] [Accepted: 08/03/2020] [Indexed: 12/16/2022]
Abstract
Plasma membranes of axon-wrapping glial cells develop specific cylindrical bilayer membranes that surround thin individual axons or axon bundles. Axons are wrapped with single layered glial cells in lower organisms whereas in the mammalian nervous system, axons are surrounded with a characteristic complex multilamellar myelin structure. The high content of lipids in myelin suggests that lipids play crucial roles in the structure and function of myelin. The most striking feature of myelin lipids is the high content of galactosylceramide (GalCer). Serological and genetic studies indicate that GalCer plays a key role in the formation and function of the myelin sheath in mammals. In contrast to mammals, Drosophila lacks GalCer. Instead of GalCer, ceramide phosphoethanolamine (CPE) has an important role to ensheath axons with glial cells in Drosophila. GalCer and CPE share similar physical properties: both lipids have a high phase transition temperature and high packing, are immiscible with cholesterol and form helical liposomes. These properties are caused by both the strong headgroup interactions and the tight packing resulting from the small size of the headgroup and the hydrogen bonds between lipid molecules. These results suggest that mammals and Drosophila wrap axons using different lipids but the same conserved principle.
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22
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Bittern J, Pogodalla N, Ohm H, Brüser L, Kottmeier R, Schirmeier S, Klämbt C. Neuron-glia interaction in the Drosophila nervous system. Dev Neurobiol 2020; 81:438-452. [PMID: 32096904 DOI: 10.1002/dneu.22737] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 02/11/2020] [Accepted: 02/24/2020] [Indexed: 12/14/2022]
Abstract
Animals are able to move and react in manifold ways to external stimuli. Thus, environmental stimuli need to be detected, information must be processed, and, finally, an output decision must be transmitted to the musculature to get the animal moving. All these processes depend on the nervous system which comprises an intricate neuronal network and many glial cells. Glial cells have an equally important contribution in nervous system function as their neuronal counterpart. Manifold roles are attributed to glia ranging from controlling neuronal cell number and axonal pathfinding to regulation of synapse formation, function, and plasticity. Glial cells metabolically support neurons and contribute to the blood-brain barrier. All of the aforementioned aspects require extensive cell-cell interactions between neurons and glial cells. Not surprisingly, many of these processes are found in all phyla executed by evolutionarily conserved molecules. Here, we review the recent advance in understanding neuron-glia interaction in Drosophila melanogaster to suggest that work in simple model organisms will shed light on the function of mammalian glial cells, too.
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Affiliation(s)
- Jonas Bittern
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Münster, Germany
| | - Nicole Pogodalla
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Münster, Germany
| | - Henrike Ohm
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Münster, Germany
| | - Lena Brüser
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Münster, Germany
| | - Rita Kottmeier
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Münster, Germany
| | - Stefanie Schirmeier
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Münster, Germany
| | - Christian Klämbt
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Münster, Germany
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23
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Mofidi H, Sarbaz Y, Golmohammadi S. A new theory based on possible existence of timing control by intracellular photons in tonically active neurons. Med Hypotheses 2019; 129:109248. [PMID: 31371078 DOI: 10.1016/j.mehy.2019.109248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 05/19/2019] [Accepted: 05/24/2019] [Indexed: 11/30/2022]
Abstract
Time perception in living organisms, especially mammals, and understanding the timing of their internal organs, have always been the topic of interest in neuroscience. In this study, our theory considers the photonic behavior on time control by some particular or some block of neurons. Photon emission by mitochondria has regular timing in intercellular process. In other words, due to the main mitochondrial function of cellular respiration as well as the source of photon emission, it is possible to deduce photon at a specific rate in TANs (Tonically Active Neurons). If photoreceptors exist in the neurons of the nervous system, photons can be received at a regulated time. Thereby, neurons can produce a constant-frequency signal for subsequent stimuli. Our studies conducted in the CNS (Central Nervous System) and TANs, and it seems that photoreceptors are present in TANs. Photons are interpreted by a series of neurons and produce an oscillating rhythm. These rhythms can be the basis of the body's chronological activity in different areas of the CNS. If this hypothesis is true, it can be deduced that an independent factor, excluding circadian activities, exists for living activities. Different neuronal structures will also be responsible for understanding the time. Although this hypothesis is far from a complete evaluation, it can compensate for some of the other problems. For instance, a series of inconsistencies that occur in some neurological diseases, such as Parkinson diseases can be well justified by this hypothesis.
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Affiliation(s)
- Hossein Mofidi
- School of Engineering Emerging Technologies, University of Tabriz, Tabriz, Iran
| | - Yashar Sarbaz
- School of Engineering Emerging Technologies, University of Tabriz, Tabriz, Iran.
| | - Saeed Golmohammadi
- School of Engineering Emerging Technologies, University of Tabriz, Tabriz, Iran
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24
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Hill AS, Jain P, Folan NE, Ben-Shahar Y. The Drosophila ERG channel seizure plays a role in the neuronal homeostatic stress response. PLoS Genet 2019; 15:e1008288. [PMID: 31393878 PMCID: PMC6687100 DOI: 10.1371/journal.pgen.1008288] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 07/04/2019] [Indexed: 11/24/2022] Open
Abstract
Neuronal physiology is particularly sensitive to acute stressors that affect excitability, many of which can trigger seizures and epilepsies. Although intrinsic neuronal homeostasis plays an important role in maintaining overall nervous system robustness and its resistance to stressors, the specific genetic and molecular mechanisms that underlie these processes are not well understood. Here we used a reverse genetic approach in Drosophila to test the hypothesis that specific voltage-gated ion channels contribute to neuronal homeostasis, robustness, and stress resistance. We found that the activity of the voltage-gated potassium channel seizure (sei), an ortholog of the mammalian ERG channel family, is essential for protecting flies from acute heat-induced seizures. Although sei is broadly expressed in the nervous system, our data indicate that its impact on the organismal robustness to acute environmental stress is primarily mediated via its action in excitatory neurons, the octopaminergic system, as well as neuropile ensheathing and perineurial glia. Furthermore, our studies suggest that human mutations in the human ERG channel (hERG), which have been primarily implicated in the cardiac Long QT Syndrome (LQTS), may also contribute to the high incidence of seizures in LQTS patients via a cardiovascular-independent neurogenic pathway.
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Affiliation(s)
- Alexis S. Hill
- Department of Biology, College of the Holy Cross, Worcester, Massachusetts, United States of America
| | - Poorva Jain
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Nicole E. Folan
- Department of Biology, College of the Holy Cross, Worcester, Massachusetts, United States of America
| | - Yehuda Ben-Shahar
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, United States of America
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25
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Lee KM, Mathies LD, Grotewiel M. Alcohol sedation in adult Drosophila is regulated by Cysteine proteinase-1 in cortex glia. Commun Biol 2019; 2:252. [PMID: 31286069 PMCID: PMC6610072 DOI: 10.1038/s42003-019-0492-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 05/30/2019] [Indexed: 02/06/2023] Open
Abstract
Although numerous studies have demonstrated that neuronal mechanisms regulate alcohol-related behaviors, very few have investigated the direct role of glia in behavioral responses to alcohol. The results described here begin to fill this gap in the alcohol behavior and gliobiology fields. Since Drosophila exhibit conserved behavioral responses to alcohol and their CNS glia are similar to mammalian CNS glia, we used Drosophila to begin exploring the role of glia in alcohol behavior. We found that knockdown of Cysteine proteinase-1 (Cp1) in glia increased Drosophila alcohol sedation and that this effect was specific to cortex glia and adulthood. These data implicate Cp1 and cortex glia in alcohol-related behaviors. Cortex glia are functionally homologous to mammalian astrocytes and Cp1 is orthologous to mammalian Cathepsin L. Our studies raise the possibility that cathepsins may influence behavioral responses to alcohol in mammals via roles in astrocytes.
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Affiliation(s)
- Kristen M. Lee
- Neuroscience Graduate Program, Virginia Commonwealth University, Richmond, VA 23298 USA
| | - Laura D. Mathies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298 USA
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, VA 23298 USA
| | - Mike Grotewiel
- Neuroscience Graduate Program, Virginia Commonwealth University, Richmond, VA 23298 USA
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, VA 23298 USA
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA 23298 USA
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Ceramide phosphoethanolamine, an enigmatic cellular membrane sphingolipid. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:1284-1292. [DOI: 10.1016/j.bbamem.2019.05.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 12/20/2018] [Accepted: 01/06/2019] [Indexed: 12/14/2022]
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Formation of tubules and helical ribbons by ceramide phosphoethanolamine-containing membranes. Sci Rep 2019; 9:5812. [PMID: 30967612 PMCID: PMC6456502 DOI: 10.1038/s41598-019-42247-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 03/19/2019] [Indexed: 11/25/2022] Open
Abstract
Ceramide phosphoethanolamine (CPE), a major sphingolipid in invertebrates, is crucial for axonal ensheathment in Drosophila. Darkfield microscopy revealed that an equimolar mixture of bovine buttermilk CPE (milk CPE) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (diC18:1 PC) tends to form tubules and helical ribbons, while pure milk CPE mainly exhibits amorphous aggregates and, at low frequency, straight needles. Negative staining electron microscopy indicated that helices and tubules were composed of multilayered 5–10 nm thick slab-like structures. Using different molecular species of PC and CPE, we demonstrated that the acyl chain length of CPE but not of PC is crucial for the formation of tubules and helices in equimolar mixtures. Incubation of the lipid suspensions at the respective phase transition temperature of CPE facilitated the formation of both tubules and helices, suggesting a dynamic lipid rearrangement during formation. Substituting diC18:1 PC with diC18:1 PE or diC18:1 PS failed to form tubules and helices. As hydrated galactosylceramide (GalCer), a major lipid in mammalian myelin, has been reported to spontaneously form tubules and helices, it is believed that the ensheathment of axons in mammals and Drosophila is based on similar physical processes with different lipids.
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