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Beath EA, Bailey C, Mahantesh Magadam M, Qiu S, McNally KL, McNally FJ. Katanin, kinesin-13, and ataxin-2 inhibit premature interaction between maternal and paternal genomes in C. elegans zygotes. eLife 2024; 13:RP97812. [PMID: 39078879 PMCID: PMC11288632 DOI: 10.7554/elife.97812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2024] Open
Abstract
Fertilization occurs before the completion of oocyte meiosis in the majority of animal species and sperm contents move long distances within the zygotes of mouse and C. elegans. If incorporated into the meiotic spindle, paternal chromosomes could be expelled into a polar body resulting in lethal monosomy. Through live imaging of fertilization in C. elegans, we found that the microtubule disassembling enzymes, katanin and kinesin-13 limit long-range movement of sperm contents and that maternal ataxin-2 maintains paternal DNA and paternal mitochondria as a cohesive unit that moves together. Depletion of katanin or double depletion of kinesin-13 and ataxin-2 resulted in the capture of the sperm contents by the meiotic spindle. Thus limiting movement of sperm contents and maintaining cohesion of sperm contents within the zygote both contribute to preventing premature interaction between maternal and paternal genomes.
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Affiliation(s)
- Elizabeth A Beath
- Department of Molecular and Cellular Biology, University of CaliforniaDavisUnited States
| | - Cynthia Bailey
- Department of Molecular and Cellular Biology, University of CaliforniaDavisUnited States
| | | | - Shuyan Qiu
- Department of Molecular and Cellular Biology, University of CaliforniaDavisUnited States
| | - Karen L McNally
- Department of Molecular and Cellular Biology, University of CaliforniaDavisUnited States
| | - Francis J McNally
- Department of Molecular and Cellular Biology, University of CaliforniaDavisUnited States
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2
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Wang JY, Liu YJ, Zhang XL, Liu YH, Jiang LL, Hu HY. PolyQ-expanded ataxin-2 aggregation impairs cellular processing-body homeostasis via sequestering the RNA helicase DDX6. J Biol Chem 2024; 300:107413. [PMID: 38810698 PMCID: PMC11254730 DOI: 10.1016/j.jbc.2024.107413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 04/02/2024] [Accepted: 04/10/2024] [Indexed: 05/31/2024] Open
Abstract
Ataxin-2 (Atx2) is a polyglutamine (polyQ) tract-containing RNA-binding protein, while its polyQ expansion may cause protein aggregation that is implicated in the pathogenesis of neurodegenerative diseases such as spinocerebellar ataxia type 2 (SCA2). However, the molecular mechanism underlying how Atx2 aggregation contributes to the proteinopathies remains elusive. Here, we investigated the influence of Atx2 aggregation on the assembly and functionality of cellular processing bodies (P-bodies) by using biochemical and fluorescence imaging approaches. We have revealed that polyQ-expanded (PQE) Atx2 sequesters the DEAD-box RNA helicase (DDX6), an essential component of P-bodies, into aggregates or puncta via some RNA sequences. The N-terminal like-Sm (LSm) domain of Atx2 (residues 82-184) and the C-terminal helicase domain of DDX6 are responsible for the interaction and specific sequestration. Moreover, sequestration of DDX6 may aggravate pre-mRNA mis-splicing, and interfere with the assembly of cellular P-bodies, releasing the endoribonuclease MARF1 that promotes mRNA decay and translational repression. Rescuing the DDX6 protein level can recover the assembly and functionality of P-bodies, preventing targeted mRNA from degradation. This study provides a line of evidence for sequestration of the P-body components and impairment of the P-body homeostasis in dysregulating RNA metabolism, which is implicated in the disease pathologies and a potential therapeutic target.
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Affiliation(s)
- Jian-Yang Wang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, PR China; University of Chinese Academy of Sciences, Beijing, PR China
| | - Ya-Jun Liu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, PR China; University of Chinese Academy of Sciences, Beijing, PR China
| | - Xiang-Le Zhang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, PR China; University of Chinese Academy of Sciences, Beijing, PR China
| | - Yin-Hu Liu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, PR China; University of Chinese Academy of Sciences, Beijing, PR China
| | - Lei-Lei Jiang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, PR China
| | - Hong-Yu Hu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, PR China.
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Beath EA, Bailey C, Magadum MM, Qiu S, McNally KL, McNally FJ. Katanin, kinesin-13 and ataxin-2 inhibit premature interaction between maternal and paternal genomes in C. elegans zygotes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.12.584242. [PMID: 38559153 PMCID: PMC10979973 DOI: 10.1101/2024.03.12.584242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Fertilization occurs before completion of oocyte meiosis in the majority of animal species and sperm contents move long distances within zygotes of mouse and C. elegans. If incorporated into the meiotic spindle, paternal chromosomes could be expelled into a polar body resulting in lethal monosomy. Through live imaging of fertilization in C. elegans, we found that the microtubule disassembling enzymes, katanin and kinesin-13 limit long range movement of sperm contents and that maternal ataxin-2 maintains paternal DNA and paternal mitochondria as a cohesive unit that moves together. Depletion of katanin or double depletion of kinesin-13 and ataxin-2 resulted in capture of the sperm contents by the meiotic spindle. Thus limiting movement of sperm contents and maintaining cohesion of sperm contents within the zygote both contribute to preventing premature interaction between maternal and paternal genomes.
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Affiliation(s)
- Elizabeth A Beath
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95618, USA
| | - Cynthia Bailey
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95618, USA
| | | | - Shuyan Qiu
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95618, USA
| | - Karen L McNally
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95618, USA
| | - Francis J McNally
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95618, USA
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4
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Hassan M, Shahzadi S, Yasir M, Chun W, Kloczkowski A. Computational prognostic evaluation of Alzheimer's drugs from FDA-approved database through structural conformational dynamics and drug repositioning approaches. Sci Rep 2023; 13:18022. [PMID: 37865690 PMCID: PMC10590448 DOI: 10.1038/s41598-023-45347-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 10/18/2023] [Indexed: 10/23/2023] Open
Abstract
Drug designing is high-priced and time taking process with low success rate. To overcome this obligation, computational drug repositioning technique is being promptly used to predict the possible therapeutic effects of FDA approved drugs against multiple diseases. In this computational study, protein modeling, shape-based screening, molecular docking, pharmacogenomics, and molecular dynamic simulation approaches have been utilized to retrieve the FDA approved drugs against AD. The predicted MADD protein structure was designed by homology modeling and characterized through different computational resources. Donepezil and galantamine were implanted as standard drugs and drugs were screened out based on structural similarities. Furthermore, these drugs were evaluated and based on binding energy (Kcal/mol) profiles against MADD through PyRx tool. Moreover, pharmacogenomics analysis showed good possible associations with AD mediated genes and confirmed through detail literature survey. The best 6 drug (darifenacin, astemizole, tubocurarine, elacridar, sertindole and tariquidar) further docked and analyzed their interaction behavior through hydrogen binding. Finally, MD simulation study were carried out on these drugs and evaluated their stability behavior by generating root mean square deviation and fluctuations (RMSD/F), radius of gyration (Rg) and soluble accessible surface area (SASA) graphs. Taken together, darifenacin, astemizole, tubocurarine, elacridar, sertindole and tariquidar displayed good lead like profile as compared with standard and can be used as possible therapeutic agent in the treatment of AD after in-vitro and in-vivo assessment.
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Affiliation(s)
- Mubashir Hassan
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, OH, 43205, USA.
| | - Saba Shahzadi
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, OH, 43205, USA
| | - Muhammad Yasir
- Department of Pharmacology, College of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Wanjoo Chun
- Department of Pharmacology, College of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Andrzej Kloczkowski
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, OH, 43205, USA.
- Department of Pediatrics, The Ohio State University, Columbus, OH, 43205, USA.
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5
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Parkkinen I, Their A, Asghar MY, Sree S, Jokitalo E, Airavaara M. Pharmacological Regulation of Endoplasmic Reticulum Structure and Calcium Dynamics: Importance for Neurodegenerative Diseases. Pharmacol Rev 2023; 75:959-978. [PMID: 37127349 DOI: 10.1124/pharmrev.122.000701] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 03/27/2023] [Accepted: 04/04/2023] [Indexed: 05/03/2023] Open
Abstract
The endoplasmic reticulum (ER) is the largest organelle of the cell, composed of a continuous network of sheets and tubules, and is involved in protein, calcium (Ca2+), and lipid homeostasis. In neurons, the ER extends throughout the cell, both somal and axodendritic compartments, and is highly important for neuronal functions. A third of the proteome of a cell, secreted and membrane-bound proteins, are processed within the ER lumen and most of these proteins are vital for neuronal activity. The brain itself is high in lipid content, and many structural lipids are produced, in part, by the ER. Cholesterol and steroid synthesis are strictly regulated in the ER of the blood-brain barrier protected brain cells. The high Ca2+ level in the ER lumen and low cytosolic concentration is needed for Ca2+-based intracellular signaling, for synaptic signaling and Ca2+ waves, and for preparing proteins for correct folding in the presence of high Ca2+ concentrations to cope with the high concentrations of extracellular milieu. Particularly, ER Ca2+ is controlled in axodendritic areas for proper neurito- and synaptogenesis and synaptic plasticity and remodeling. In this review, we cover the physiologic functions of the neuronal ER and discuss it in context of common neurodegenerative diseases, focusing on pharmacological regulation of ER Ca2+ Furthermore, we postulate that heterogeneity of the ER, its protein folding capacity, and ensuring Ca2+ regulation are crucial factors for the aging and selective vulnerability of neurons in various neurodegenerative diseases. SIGNIFICANCE STATEMENT: Endoplasmic reticulum (ER) Ca2+ regulators are promising therapeutic targets for degenerative diseases for which efficacious drug therapies do not exist. The use of pharmacological probes targeting maintenance and restoration of ER Ca2+ can provide restoration of protein homeostasis (e.g., folding of complex plasma membrane signaling receptors) and slow down the degeneration process of neurons.
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Affiliation(s)
- Ilmari Parkkinen
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Anna Their
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Muhammad Yasir Asghar
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Sreesha Sree
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Eija Jokitalo
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Mikko Airavaara
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
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6
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Coutelier M, Jacoupy M, Janer A, Renaud F, Auger N, Saripella GV, Ancien F, Pucci F, Rooman M, Gilis D, Larivière R, Sgarioto N, Valter R, Guillot-Noel L, Le Ber I, Sayah S, Charles P, Nümann A, Pauly MG, Helmchen C, Deininger N, Haack TB, Brais B, Brice A, Trégouët DA, El Hachimi KH, Shoubridge EA, Durr A, Stevanin G. NPTX1 mutations trigger endoplasmic reticulum stress and cause autosomal dominant cerebellar ataxia. Brain 2022; 145:1519-1534. [PMID: 34788392 DOI: 10.1093/brain/awab407] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 09/25/2021] [Accepted: 10/10/2021] [Indexed: 11/14/2022] Open
Abstract
With more than 40 causative genes identified so far, autosomal dominant cerebellar ataxias exhibit a remarkable genetic heterogeneity. Yet, half the patients are lacking a molecular diagnosis. In a large family with nine sampled affected members, we performed exome sequencing combined with whole-genome linkage analysis. We identified a missense variant in NPTX1, NM_002522.3:c.1165G>A: p.G389R, segregating with the phenotype. Further investigations with whole-exome sequencing and an amplicon-based panel identified four additional unrelated families segregating the same variant, for whom a common founder effect could be excluded. A second missense variant, NM_002522.3:c.980A>G: p.E327G, was identified in a fifth familial case. The NPTX1-associated phenotype consists of a late-onset, slowly progressive, cerebellar ataxia, with downbeat nystagmus, cognitive impairment reminiscent of cerebellar cognitive affective syndrome, myoclonic tremor and mild cerebellar vermian atrophy on brain imaging. NPTX1 encodes the neuronal pentraxin 1, a secreted protein with various cellular and synaptic functions. Both variants affect conserved amino acid residues and are extremely rare or absent from public databases. In COS7 cells, overexpression of both neuronal pentraxin 1 variants altered endoplasmic reticulum morphology and induced ATF6-mediated endoplasmic reticulum stress, associated with cytotoxicity. In addition, the p.E327G variant abolished neuronal pentraxin 1 secretion, as well as its capacity to form a high molecular weight complex with the wild-type protein. Co-immunoprecipitation experiments coupled with mass spectrometry analysis demonstrated abnormal interactions of this variant with the cytoskeleton. In agreement with these observations, in silico modelling of the neuronal pentraxin 1 complex evidenced a destabilizing effect for the p.E327G substitution, located at the interface between monomers. On the contrary, the p.G389 residue, located at the protein surface, had no predictable effect on the complex stability. Our results establish NPTX1 as a new causative gene in autosomal dominant cerebellar ataxias. We suggest that variants in NPTX1 can lead to cerebellar ataxia due to endoplasmic reticulum stress, mediated by ATF6, and associated to a destabilization of NP1 polymers in a dominant-negative manner for one of the variants.
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Affiliation(s)
- Marie Coutelier
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute, ICM, INSERM U 1127, CNRS UMR 7225, APHP, Pitié-Salpêtrière University Hospital, 75013 Paris, France
| | - Maxime Jacoupy
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute, ICM, INSERM U 1127, CNRS UMR 7225, APHP, Pitié-Salpêtrière University Hospital, 75013 Paris, France
- Department of Human Genetics, McGill University, H3A 0C7 Montreal, Canada
- Montreal Neurological Institute, McGill University, H3A 2B4 Montreal, Canada
| | - Alexandre Janer
- Department of Human Genetics, McGill University, H3A 0C7 Montreal, Canada
- Montreal Neurological Institute, McGill University, H3A 2B4 Montreal, Canada
| | - Flore Renaud
- CNRS UMR 9019, Gustave Roussy, Université Paris-Saclay, 94805 Villejuif, France
- Neurogenetics team, Ecole Pratique des Hautes Etudes (EPHE), Paris Sciences Lettres (PSL) Research University, 75014, Paris, France
| | - Nicolas Auger
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute, ICM, INSERM U 1127, CNRS UMR 7225, APHP, Pitié-Salpêtrière University Hospital, 75013 Paris, France
- Neurogenetics team, Ecole Pratique des Hautes Etudes (EPHE), Paris Sciences Lettres (PSL) Research University, 75014, Paris, France
| | - Ganapathi-Varma Saripella
- ICAN Institute, Pitié-Salpêtrière University Hospital, INSERM, Sorbonne Université, 75013 Paris, France
| | - François Ancien
- Computational Biology and Bioinformatics, Université libre de Bruxelles, 1050 Bruxelles, Belgium
| | - Fabrizio Pucci
- Computational Biology and Bioinformatics, Université libre de Bruxelles, 1050 Bruxelles, Belgium
| | - Marianne Rooman
- Computational Biology and Bioinformatics, Université libre de Bruxelles, 1050 Bruxelles, Belgium
| | - Dimitri Gilis
- Computational Biology and Bioinformatics, Université libre de Bruxelles, 1050 Bruxelles, Belgium
| | - Roxanne Larivière
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, H3A 2B4 Montreal, Canada
| | - Nicolas Sgarioto
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, H3A 2B4 Montreal, Canada
| | - Rémi Valter
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute, ICM, INSERM U 1127, CNRS UMR 7225, APHP, Pitié-Salpêtrière University Hospital, 75013 Paris, France
- Neurogenetics team, Ecole Pratique des Hautes Etudes (EPHE), Paris Sciences Lettres (PSL) Research University, 75014, Paris, France
| | - Léna Guillot-Noel
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute, ICM, INSERM U 1127, CNRS UMR 7225, APHP, Pitié-Salpêtrière University Hospital, 75013 Paris, France
- Neurogenetics team, Ecole Pratique des Hautes Etudes (EPHE), Paris Sciences Lettres (PSL) Research University, 75014, Paris, France
| | - Isabelle Le Ber
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute, ICM, INSERM U 1127, CNRS UMR 7225, APHP, Pitié-Salpêtrière University Hospital, 75013 Paris, France
| | - Sabrina Sayah
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute, ICM, INSERM U 1127, CNRS UMR 7225, APHP, Pitié-Salpêtrière University Hospital, 75013 Paris, France
| | - Perrine Charles
- Department of Genetics, APHP, Pitié-Salpêtrière University Hospital, 75013 Paris, France
| | - Astrid Nümann
- Department of Neurology, Charité University Hospital Berlin, 10117 Berlin, Germany
| | - Martje G Pauly
- Department of Neurology, University Hospital Schleswig Holstein Campus Luebeck, 23562 Luebeck, Germany
- Institute of Neurogenetics, University of Luebeck, 23562 Luebeck, Germany
| | - Christoph Helmchen
- Department of Neurology, University Hospital Schleswig Holstein Campus Luebeck, 23562 Luebeck, Germany
| | - Natalie Deininger
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076 Tuebingen, Germany
| | - Tobias B Haack
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076 Tuebingen, Germany
- Centre for Rare Diseases, University of Tübingen, 72076 Tuebingen, Germany
| | - Bernard Brais
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, H3A 2B4 Montreal, Canada
| | - Alexis Brice
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute, ICM, INSERM U 1127, CNRS UMR 7225, APHP, Pitié-Salpêtrière University Hospital, 75013 Paris, France
| | - David-Alexandre Trégouët
- ICAN Institute, Pitié-Salpêtrière University Hospital, INSERM, Sorbonne Université, 75013 Paris, France
- Université de Bordeaux, INSERM U1219, Bordeaux Population Health Research Center, 33076 Bordeaux, France
| | - Khalid H El Hachimi
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute, ICM, INSERM U 1127, CNRS UMR 7225, APHP, Pitié-Salpêtrière University Hospital, 75013 Paris, France
- Neurogenetics team, Ecole Pratique des Hautes Etudes (EPHE), Paris Sciences Lettres (PSL) Research University, 75014, Paris, France
| | - Eric A Shoubridge
- Department of Human Genetics, McGill University, H3A 0C7 Montreal, Canada
- Montreal Neurological Institute, McGill University, H3A 2B4 Montreal, Canada
| | - Alexandra Durr
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute, ICM, INSERM U 1127, CNRS UMR 7225, APHP, Pitié-Salpêtrière University Hospital, 75013 Paris, France
| | - Giovanni Stevanin
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute, ICM, INSERM U 1127, CNRS UMR 7225, APHP, Pitié-Salpêtrière University Hospital, 75013 Paris, France
- Neurogenetics team, Ecole Pratique des Hautes Etudes (EPHE), Paris Sciences Lettres (PSL) Research University, 75014, Paris, France
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7
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Del Castillo U, Norkett R, Lu W, Serpinskaya A, Gelfand VI. Ataxin-2 is essential for cytoskeletal dynamics and neurodevelopment in Drosophila. iScience 2022; 25:103536. [PMID: 34977501 PMCID: PMC8689088 DOI: 10.1016/j.isci.2021.103536] [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: 04/30/2021] [Revised: 08/19/2021] [Accepted: 11/25/2021] [Indexed: 12/03/2022] Open
Abstract
Ataxin-2 (Atx2) is a highly conserved RNA binding protein. Atx2 undergoes polyglutamine expansion leading to amyotrophic lateral sclerosis (ALS) or spinocerebellar ataxia type 2 (SCA2). However, the physiological functions of Atx2 in neurons remain unknown. Here, using the powerful genetics of Drosophila, we show that Atx2 is essential for normal neuronal cytoskeletal dynamics and organelle trafficking. Upon neuron-specific Atx2 loss, the microtubule and actin networks were abnormally stabilized and cargo transport was drastically inhibited. Depletion of Atx2 caused multiple morphological defects in the nervous system of third instar larvae. These include reduced brain size, impaired axon development, and decreased dendrite outgrowth. Defects in the nervous system caused loss of the ability to crawl and lethality at the pupal stage. Taken together, these data mark Atx2 as a major regulator of cytoskeletal dynamics and denote Atx2 as an essential gene in neurodevelopment, as well as a neurodegenerative factor. Atx2 is a major regulator of the cytoskeleton in neurons Atx2 is responsible for maintaining dynamic cytoskeletal networks Atx2 depletion in the Drosophila larval CNS severely impairs organelle transport Atx2 is necessary for correct neurite outgrowth and CNS development in Drosophila
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Affiliation(s)
- Urko Del Castillo
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Rosalind Norkett
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Wen Lu
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Anna Serpinskaya
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Vladimir I Gelfand
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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8
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Intertwined and Finely Balanced: Endoplasmic Reticulum Morphology, Dynamics, Function, and Diseases. Cells 2021; 10:cells10092341. [PMID: 34571990 PMCID: PMC8472773 DOI: 10.3390/cells10092341] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/02/2021] [Accepted: 09/04/2021] [Indexed: 02/07/2023] Open
Abstract
The endoplasmic reticulum (ER) is an organelle that is responsible for many essential subcellular processes. Interconnected narrow tubules at the periphery and thicker sheet-like regions in the perinuclear region are linked to the nuclear envelope. It is becoming apparent that the complex morphology and dynamics of the ER are linked to its function. Mutations in the proteins involved in regulating ER structure and movement are implicated in many diseases including neurodegenerative diseases such as Alzheimer’s, Parkinson’s, and amyotrophic lateral sclerosis (ALS). The ER is also hijacked by pathogens to promote their replication. Bacteria such as Legionella pneumophila and Chlamydia trachomatis, as well as the Zika virus, bind to ER morphology and dynamics-regulating proteins to exploit the functions of the ER to their advantage. This review covers our understanding of ER morphology, including the functional subdomains and membrane contact sites that the organelle forms. We also focus on ER dynamics and the current efforts to quantify ER motion and discuss the diseases related to ER morphology and dynamics.
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9
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Sechi S, Karimpour-Ghahnavieh A, Frappaolo A, Di Francesco L, Piergentili R, Schininà E, D’Avino PP, Giansanti MG. Identification of GOLPH3 Partners in Drosophila Unveils Potential Novel Roles in Tumorigenesis and Neural Disorders. Cells 2021; 10:cells10092336. [PMID: 34571985 PMCID: PMC8468827 DOI: 10.3390/cells10092336] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/01/2021] [Accepted: 09/03/2021] [Indexed: 12/28/2022] Open
Abstract
Golgi phosphoprotein 3 (GOLPH3) is a highly conserved peripheral membrane protein localized to the Golgi apparatus and the cytosol. GOLPH3 binding to Golgi membranes depends on phosphatidylinositol 4-phosphate [PI(4)P] and regulates Golgi architecture and vesicle trafficking. GOLPH3 overexpression has been correlated with poor prognosis in several cancers, but the molecular mechanisms that link GOLPH3 to malignant transformation are poorly understood. We recently showed that PI(4)P-GOLPH3 couples membrane trafficking with contractile ring assembly during cytokinesis in dividing Drosophila spermatocytes. Here, we use affinity purification coupled with mass spectrometry (AP-MS) to identify the protein-protein interaction network (interactome) of Drosophila GOLPH3 in testes. Analysis of the GOLPH3 interactome revealed enrichment for proteins involved in vesicle-mediated trafficking, cell proliferation and cytoskeleton dynamics. In particular, we found that dGOLPH3 interacts with the Drosophila orthologs of Fragile X mental retardation protein and Ataxin-2, suggesting a potential role in the pathophysiology of disorders of the nervous system. Our findings suggest novel molecular targets associated with GOLPH3 that might be relevant for therapeutic intervention in cancers and other human diseases.
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Affiliation(s)
- Stefano Sechi
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Angela Karimpour-Ghahnavieh
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Anna Frappaolo
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Laura Di Francesco
- Dipartimento di Scienze Biochimiche A. Rossi Fanelli, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (L.D.F.); (E.S.)
| | - Roberto Piergentili
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Eugenia Schininà
- Dipartimento di Scienze Biochimiche A. Rossi Fanelli, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (L.D.F.); (E.S.)
| | - Pier Paolo D’Avino
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK;
| | - Maria Grazia Giansanti
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
- Correspondence: ; Tel.: +39-064-991-2555
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10
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Cendelin J, Cvetanovic M, Gandelman M, Hirai H, Orr HT, Pulst SM, Strupp M, Tichanek F, Tuma J, Manto M. Consensus Paper: Strengths and Weaknesses of Animal Models of Spinocerebellar Ataxias and Their Clinical Implications. THE CEREBELLUM 2021; 21:452-481. [PMID: 34378174 DOI: 10.1007/s12311-021-01311-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/21/2021] [Indexed: 01/02/2023]
Abstract
Spinocerebellar ataxias (SCAs) represent a large group of hereditary degenerative diseases of the nervous system, in particular the cerebellum, and other systems that manifest with a variety of progressive motor, cognitive, and behavioral deficits with the leading symptom of cerebellar ataxia. SCAs often lead to severe impairments of the patient's functioning, quality of life, and life expectancy. For SCAs, there are no proven effective pharmacotherapies that improve the symptoms or substantially delay disease progress, i.e., disease-modifying therapies. To study SCA pathogenesis and potential therapies, animal models have been widely used and are an essential part of pre-clinical research. They mainly include mice, but also other vertebrates and invertebrates. Each animal model has its strengths and weaknesses arising from model animal species, type of genetic manipulation, and similarity to human diseases. The types of murine and non-murine models of SCAs, their contribution to the investigation of SCA pathogenesis, pathological phenotype, and therapeutic approaches including their advantages and disadvantages are reviewed in this paper. There is a consensus among the panel of experts that (1) animal models represent valuable tools to improve our understanding of SCAs and discover and assess novel therapies for this group of neurological disorders characterized by diverse mechanisms and differential degenerative progressions, (2) thorough phenotypic assessment of individual animal models is required for studies addressing therapeutic approaches, (3) comparative studies are needed to bring pre-clinical research closer to clinical trials, and (4) mouse models complement cellular and invertebrate models which remain limited in terms of clinical translation for complex neurological disorders such as SCAs.
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Affiliation(s)
- Jan Cendelin
- Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic. .,Laboratory of Neurodegenerative Disorders, Biomedical Center, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic.
| | - Marija Cvetanovic
- Department of Neuroscience, Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Mandi Gandelman
- Department of Neurology, University of Utah, 175 North Medical Drive East, Salt Lake City, UT, 84132, USA
| | - Hirokazu Hirai
- Department of Neurophysiology and Neural Repair, Gunma University Graduate School of Medicine, 3-39-22, Gunma, 371-8511, Japan.,Viral Vector Core, Gunma University Initiative for Advanced Research (GIAR), Gunma, 371-8511, Japan
| | - Harry T Orr
- Department of Laboratory Medicine and Pathology, Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Stefan M Pulst
- Department of Neurology, University of Utah, 175 North Medical Drive East, Salt Lake City, UT, 84132, USA
| | - Michael Strupp
- Department of Neurology and German Center for Vertigo and Balance Disorders, Hospital of the Ludwig-Maximilians University, Munich, Campus Grosshadern, Marchioninistr. 15, 81377, Munich, Germany
| | - Filip Tichanek
- Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic.,Laboratory of Neurodegenerative Disorders, Biomedical Center, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic
| | - Jan Tuma
- Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic.,The Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MC 7843, San Antonio, TX, 78229, USA
| | - Mario Manto
- Unité des Ataxies Cérébelleuses, Service de Neurologie, CHU-Charleroi, Charleroi, Belgium.,Service des Neurosciences, Université de Mons, UMons, Mons, Belgium
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11
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Morphological Heterogeneity of the Endoplasmic Reticulum within Neurons and Its Implications in Neurodegeneration. Cells 2021; 10:cells10050970. [PMID: 33919188 PMCID: PMC8143122 DOI: 10.3390/cells10050970] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/13/2021] [Accepted: 04/19/2021] [Indexed: 12/19/2022] Open
Abstract
The endoplasmic reticulum (ER) is a multipurpose organelle comprising dynamic structural subdomains, such as ER sheets and tubules, serving to maintain protein, calcium, and lipid homeostasis. In neurons, the single ER is compartmentalized with a careful segregation of the structural subdomains in somatic and neurite (axodendritic) regions. The distribution and arrangement of these ER subdomains varies between different neuronal types. Mutations in ER membrane shaping proteins and morphological changes in the ER are associated with various neurodegenerative diseases implying significance of ER morphology in maintaining neuronal integrity. Specific neurons, such as the highly arborized dopaminergic neurons, are prone to stress and neurodegeneration. Differences in morphology and functionality of ER between the neurons may account for their varied sensitivity to stress and neurodegenerative changes. In this review, we explore the neuronal ER and discuss its distinct morphological attributes and specific functions. We hypothesize that morphological heterogeneity of the ER in neurons is an important factor that accounts for their selective susceptibility to neurodegeneration.
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12
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Singh A, Hulsmeier J, Kandi AR, Pothapragada SS, Hillebrand J, Petrauskas A, Agrawal K, RT K, Thiagarajan D, Jayaprakashappa D, VijayRaghavan K, Ramaswami M, Bakthavachalu B. Antagonistic roles for Ataxin-2 structured and disordered domains in RNP condensation. eLife 2021; 10:e60326. [PMID: 33689682 PMCID: PMC7946432 DOI: 10.7554/elife.60326] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 02/23/2021] [Indexed: 02/07/2023] Open
Abstract
Ataxin-2 (Atx2) is a translational control molecule mutated in spinocerebellar ataxia type II and amyotrophic lateral sclerosis. While intrinsically disordered domains (IDRs) of Atx2 facilitate mRNP condensation into granules, how IDRs work with structured domains to enable positive and negative regulation of target mRNAs remains unclear. Using the Targets of RNA-Binding Proteins Identified by Editing technology, we identified an extensive data set of Atx2-target mRNAs in the Drosophila brain and S2 cells. Atx2 interactions with AU-rich elements in 3'UTRs appear to modulate stability/turnover of a large fraction of these target mRNAs. Further genomic and cell biological analyses of Atx2 domain deletions demonstrate that Atx2 (1) interacts closely with target mRNAs within mRNP granules, (2) contains distinct protein domains that drive or oppose RNP-granule assembly, and (3) has additional essential roles outside of mRNP granules. These findings increase the understanding of neuronal translational control mechanisms and inform strategies for Atx2-based interventions under development for neurodegenerative disease.
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Affiliation(s)
- Amanjot Singh
- National Centre for Biological SciencesBangaloreIndia
| | - Joern Hulsmeier
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College DublinDublinIreland
| | - Arvind Reddy Kandi
- National Centre for Biological SciencesBangaloreIndia
- Tata Institute for Genetics and Society Centre at inStem, Bellary RoadBangaloreIndia
| | | | - Jens Hillebrand
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College DublinDublinIreland
| | - Arnas Petrauskas
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College DublinDublinIreland
| | - Khushboo Agrawal
- Tata Institute for Genetics and Society Centre at inStem, Bellary RoadBangaloreIndia
- School of Biotechnology, Amrita Vishwa Vidyapeetham UniversityKollamIndia
| | - Krishnan RT
- National Centre for Biological SciencesBangaloreIndia
| | | | | | | | - Mani Ramaswami
- National Centre for Biological SciencesBangaloreIndia
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College DublinDublinIreland
| | - Baskar Bakthavachalu
- National Centre for Biological SciencesBangaloreIndia
- Tata Institute for Genetics and Society Centre at inStem, Bellary RoadBangaloreIndia
- School of Basic Sciences, Indian Institute of TechnologyMandiIndia
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13
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Canet-Pons J, Sen NE, Arsović A, Almaguer-Mederos LE, Halbach MV, Key J, Döring C, Kerksiek A, Picchiarelli G, Cassel R, René F, Dieterlé S, Fuchs NV, König R, Dupuis L, Lütjohann D, Gispert S, Auburger G. Atxn2-CAG100-KnockIn mouse spinal cord shows progressive TDP43 pathology associated with cholesterol biosynthesis suppression. Neurobiol Dis 2021; 152:105289. [PMID: 33577922 DOI: 10.1016/j.nbd.2021.105289] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 12/11/2020] [Accepted: 02/03/2021] [Indexed: 12/12/2022] Open
Abstract
Large polyglutamine expansions in Ataxin-2 (ATXN2) cause multi-system nervous atrophy in Spinocerebellar Ataxia type 2 (SCA2). Intermediate size expansions carry a risk for selective motor neuron degeneration, known as Amyotrophic Lateral Sclerosis (ALS). Conversely, the depletion of ATXN2 prevents disease progression in ALS. Although ATXN2 interacts directly with RNA, and in ALS pathogenesis there is a crucial role of RNA toxicity, the affected functional pathways remain ill defined. Here, we examined an authentic SCA2 mouse model with Atxn2-CAG100-KnockIn for a first definition of molecular mechanisms in spinal cord pathology. Neurophysiology of lower limbs detected sensory neuropathy rather than motor denervation. Triple immunofluorescence demonstrated cytosolic ATXN2 aggregates sequestrating TDP43 and TIA1 from the nucleus. In immunoblots, this was accompanied by elevated CASP3, RIPK1 and PQBP1 abundance. RT-qPCR showed increase of Grn, Tlr7 and Rnaset2 mRNA versus Eif5a2, Dcp2, Uhmk1 and Kif5a decrease. These SCA2 findings overlap well with known ALS features. Similar to other ataxias and dystonias, decreased mRNA levels for Unc80, Tacr1, Gnal, Ano3, Kcna2, Elovl5 and Cdr1 contrasted with Gpnmb increase. Preterminal stage tissue showed strongly activated microglia containing ATXN2 aggregates, with parallel astrogliosis. Global transcriptome profiles from stages of incipient motor deficit versus preterminal age identified molecules with progressive downregulation, where a cluster of cholesterol biosynthesis enzymes including Dhcr24, Msmo1, Idi1 and Hmgcs1 was prominent. Gas chromatography demonstrated a massive loss of crucial cholesterol precursor metabolites. Overall, the ATXN2 protein aggregation process affects diverse subcellular compartments, in particular stress granules, endoplasmic reticulum and receptor tyrosine kinase signaling. These findings identify new targets and potential biomarkers for neuroprotective therapies.
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Affiliation(s)
- Júlia Canet-Pons
- Experimental Neurology, Medical Faculty, Goethe University, 60590 Frankfurt am Main, Germany
| | - Nesli-Ece Sen
- Experimental Neurology, Medical Faculty, Goethe University, 60590 Frankfurt am Main, Germany; Faculty of Biosciences, Goethe University, 60438 Frankfurt am Main, Germany
| | - Aleksandar Arsović
- Experimental Neurology, Medical Faculty, Goethe University, 60590 Frankfurt am Main, Germany
| | - Luis-Enrique Almaguer-Mederos
- Experimental Neurology, Medical Faculty, Goethe University, 60590 Frankfurt am Main, Germany; Center for Investigation and Rehabilitation of Hereditary Ataxias (CIRAH), Holguín, Cuba
| | - Melanie V Halbach
- Experimental Neurology, Medical Faculty, Goethe University, 60590 Frankfurt am Main, Germany
| | - Jana Key
- Experimental Neurology, Medical Faculty, Goethe University, 60590 Frankfurt am Main, Germany; Faculty of Biosciences, Goethe University, 60438 Frankfurt am Main, Germany
| | - Claudia Döring
- Dr. Senckenberg Institute of Pathology, Medical Faculty, Goethe University, 60590 Frankfurt am Main, Germany
| | - Anja Kerksiek
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, 53127 Bonn, Nordrhein-Westfalen, Germany
| | - Gina Picchiarelli
- UMRS-1118 INSERM, Faculty of Medicine, University of Strasbourg, 67000 Strasbourg, France
| | - Raphaelle Cassel
- UMRS-1118 INSERM, Faculty of Medicine, University of Strasbourg, 67000 Strasbourg, France
| | - Frédérique René
- UMRS-1118 INSERM, Faculty of Medicine, University of Strasbourg, 67000 Strasbourg, France
| | - Stéphane Dieterlé
- UMRS-1118 INSERM, Faculty of Medicine, University of Strasbourg, 67000 Strasbourg, France
| | - Nina V Fuchs
- Host-Pathogen Interactions, Paul-Ehrlich-Institute, 63225 Langen, Germany
| | - Renate König
- Host-Pathogen Interactions, Paul-Ehrlich-Institute, 63225 Langen, Germany
| | - Luc Dupuis
- UMRS-1118 INSERM, Faculty of Medicine, University of Strasbourg, 67000 Strasbourg, France
| | - Dieter Lütjohann
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, 53127 Bonn, Nordrhein-Westfalen, Germany
| | - Suzana Gispert
- Experimental Neurology, Medical Faculty, Goethe University, 60590 Frankfurt am Main, Germany
| | - Georg Auburger
- Experimental Neurology, Medical Faculty, Goethe University, 60590 Frankfurt am Main, Germany.
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14
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Öztürk Z, O’Kane CJ, Pérez-Moreno JJ. Axonal Endoplasmic Reticulum Dynamics and Its Roles in Neurodegeneration. Front Neurosci 2020; 14:48. [PMID: 32116502 PMCID: PMC7025499 DOI: 10.3389/fnins.2020.00048] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/13/2020] [Indexed: 12/13/2022] Open
Abstract
The physical continuity of axons over long cellular distances poses challenges for their maintenance. One organelle that faces this challenge is endoplasmic reticulum (ER); unlike other intracellular organelles, this forms a physically continuous network throughout the cell, with a single membrane and a single lumen. In axons, ER is mainly smooth, forming a tubular network with occasional sheets or cisternae and low amounts of rough ER. It has many potential roles: lipid biosynthesis, glucose homeostasis, a Ca2+ store, protein export, and contacting and regulating other organelles. This tubular network structure is determined by ER-shaping proteins, mutations in some of which are causative for neurodegenerative disorders such as hereditary spastic paraplegia (HSP). While axonal ER shares many features with the tubular ER network in other contexts, these features must be adapted to the long and narrow dimensions of axons. ER appears to be physically continuous throughout axons, over distances that are enormous on a subcellular scale. It is therefore a potential channel for long-distance or regional communication within neurons, independent of action potentials or physical transport of cargos, but involving its physiological roles such as Ca2+ or organelle homeostasis. Despite its apparent stability, axonal ER is highly dynamic, showing features like anterograde and retrograde transport, potentially reflecting continuous fusion and breakage of the network. Here we discuss the transport processes that must contribute to this dynamic behavior of ER. We also discuss the model that these processes underpin a homeostatic process that ensures both enough ER to maintain continuity of the network and repair breaks in it, but not too much ER that might disrupt local cellular physiology. Finally, we discuss how failure of ER organization in axons could lead to axon degenerative diseases, and how a requirement for ER continuity could make distal axons most susceptible to degeneration in conditions that disrupt ER continuity.
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Affiliation(s)
| | - Cahir J. O’Kane
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
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15
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Sen NE, Arsovic A, Meierhofer D, Brodesser S, Oberschmidt C, Canet-Pons J, Kaya ZE, Halbach MV, Gispert S, Sandhoff K, Auburger G. In Human and Mouse Spino-Cerebellar Tissue, Ataxin-2 Expansion Affects Ceramide-Sphingomyelin Metabolism. Int J Mol Sci 2019; 20:E5854. [PMID: 31766565 PMCID: PMC6928749 DOI: 10.3390/ijms20235854] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 02/08/2023] Open
Abstract
Ataxin-2 (human gene symbol ATXN2) acts during stress responses, modulating mRNA translation and nutrient metabolism. Ataxin-2 knockout mice exhibit progressive obesity, dyslipidemia, and insulin resistance. Conversely, the progressive ATXN2 gain of function due to the fact of polyglutamine (polyQ) expansions leads to a dominantly inherited neurodegenerative process named spinocerebellar ataxia type 2 (SCA2) with early adipose tissue loss and late muscle atrophy. We tried to understand lipid dysregulation in a SCA2 patient brain and in an authentic mouse model. Thin layer chromatography of a patient cerebellum was compared to the lipid metabolome of Atxn2-CAG100-Knockin (KIN) mouse spinocerebellar tissue. The human pathology caused deficits of sulfatide, galactosylceramide, cholesterol, C22/24-sphingomyelin, and gangliosides GM1a/GD1b despite quite normal levels of C18-sphingomyelin. Cerebellum and spinal cord from the KIN mouse showed a consistent decrease of various ceramides with a significant elevation of sphingosine in the more severely affected spinal cord. Deficiency of C24/26-sphingomyelins contrasted with excess C18/20-sphingomyelin. Spinocerebellar expression profiling revealed consistent reductions of CERS protein isoforms, Sptlc2 and Smpd3, but upregulation of Cers2 mRNA, as prominent anomalies in the ceramide-sphingosine metabolism. Reduction of Asah2 mRNA correlated to deficient S1P levels. In addition, downregulations for the elongase Elovl1, Elovl4, Elovl5 mRNAs and ELOVL4 protein explain the deficit of very long-chain sphingomyelin. Reduced ASMase protein levels correlated to the accumulation of long-chain sphingomyelin. Overall, a deficit of myelin lipids was prominent in SCA2 nervous tissue at prefinal stage and not compensated by transcriptional adaptation of several metabolic enzymes. Myelination is controlled by mTORC1 signals; thus, our human and murine observations are in agreement with the known role of ATXN2 yeast, nematode, and mouse orthologs as mTORC1 inhibitors and autophagy promoters.
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Affiliation(s)
- Nesli-Ece Sen
- Experimental Neurology, Building 89, Goethe University Medical Faculty, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany; (N.-E.S.); (A.A.); (C.O.); (J.C.-P.); (Z.-E.K.); (M.-V.H.); (S.G.)
- Faculty of Biosciences, Goethe-University, 60438 Frankfurt am Main, Germany
| | - Aleksandar Arsovic
- Experimental Neurology, Building 89, Goethe University Medical Faculty, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany; (N.-E.S.); (A.A.); (C.O.); (J.C.-P.); (Z.-E.K.); (M.-V.H.); (S.G.)
| | - David Meierhofer
- Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany;
| | - Susanne Brodesser
- Membrane Biology and Lipid Biochemistry Unit, Life and Medical Sciences Institute, University of Bonn, 53121 Bonn, Germany;
| | - Carola Oberschmidt
- Experimental Neurology, Building 89, Goethe University Medical Faculty, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany; (N.-E.S.); (A.A.); (C.O.); (J.C.-P.); (Z.-E.K.); (M.-V.H.); (S.G.)
| | - Júlia Canet-Pons
- Experimental Neurology, Building 89, Goethe University Medical Faculty, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany; (N.-E.S.); (A.A.); (C.O.); (J.C.-P.); (Z.-E.K.); (M.-V.H.); (S.G.)
| | - Zeynep-Ece Kaya
- Experimental Neurology, Building 89, Goethe University Medical Faculty, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany; (N.-E.S.); (A.A.); (C.O.); (J.C.-P.); (Z.-E.K.); (M.-V.H.); (S.G.)
- Cerrahpasa School of Medicine, Istanbul University, 34098 Istanbul, Turkey
| | - Melanie-Vanessa Halbach
- Experimental Neurology, Building 89, Goethe University Medical Faculty, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany; (N.-E.S.); (A.A.); (C.O.); (J.C.-P.); (Z.-E.K.); (M.-V.H.); (S.G.)
| | - Suzana Gispert
- Experimental Neurology, Building 89, Goethe University Medical Faculty, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany; (N.-E.S.); (A.A.); (C.O.); (J.C.-P.); (Z.-E.K.); (M.-V.H.); (S.G.)
| | - Konrad Sandhoff
- Membrane Biology and Lipid Biochemistry Unit, Life and Medical Sciences Institute, University of Bonn, 53121 Bonn, Germany;
| | - Georg Auburger
- Experimental Neurology, Building 89, Goethe University Medical Faculty, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany; (N.-E.S.); (A.A.); (C.O.); (J.C.-P.); (Z.-E.K.); (M.-V.H.); (S.G.)
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