title: Disruption of Protein Processing in the Endoplasmic Reticulum of DYT1 Knock-in Mice Implicates Novel Pathways in Dystonia Pathogenesis.
abstract: Dystonia type 1 (DYT1) is a dominantly inherited neurological disease caused by mutations in TOR1A, the gene encoding the endoplasmic reticulum (ER)-resident protein torsinA. Previous work mostly completed in cell-based systems suggests that mutant torsinA alters protein processing in the secretory pathway. We hypothesized that inducing ER stress in the mammalian brain in vivo would trigger or exacerbate mutant torsinA-induced dysfunction. To test this hypothesis, we crossed DYT1 knock-in with p58(IPK)-null mice. The ER co-chaperone p58(IPK) interacts with BiP and assists in protein maturation by helping to fold ER cargo. Its deletion increases the cellular sensitivity to ER stress. We found a lower generation of DYT1 knock-in/p58 knock-out mice than expected from this cross, suggesting a developmental interaction that influences viability. However, surviving animals did not exhibit abnormal motor function. Analysis of brain tissue uncovered dysregulation of eiF2α and Akt/mTOR translational control pathways in the DYT1 brain, a finding confirmed in a second rodent model and in human brain. Finally, an unbiased proteomic analysis identified relevant changes in the neuronal protein landscape suggesting abnormal ER protein metabolism and calcium dysregulation. Functional studies confirmed the interaction between the DYT1 genotype and neuronal calcium dynamics. Overall, these findings advance our knowledge on dystonia, linking translational control pathways and calcium physiology to dystonia pathogenesis and identifying potential new pharmacological targets.
  
  
  
  Dystonia type 1 (DYT1) is one of the different forms of inherited dystonia, a neurological disorder characterized by involuntary, disabling movements. DYT1 is caused by mutations in the gene that encodes the endoplasmic reticulum (ER)-resident protein torsinA. How mutant torsinA causes neuronal dysfunction remains unknown. Here, we show the behavioral and molecular consequences of stressing the ER in DYT1 mice by increasing the amount of misfolded proteins. This resulted in the generation of a reduced number of animals, evidence of abnormal ER protein processing and dysregulation of translational control pathways. The work described here proposes a shared mechanism for different forms of dystonia, links for the first time known biological pathways to dystonia pathogenesis, and uncovers potential pharmacological targets for its treatment.
authors.affiliation: Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104.
authors.forename: Genevieve
authors.initials: G
authors.lastname: Beauvais
authors.affiliation: Department of Neurology and.
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Bode
authors.affiliation: Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104.
authors.forename: Jaime L
authors.identifier: 0000-0002-8273-5339
authors.initials: JL
authors.lastname: Watson
authors.affiliation: Department of Medicine, Carver College of Medicine, and.
authors.forename: Hsiang
authors.initials: H
authors.lastname: Wen
authors.affiliation: Department of Medicine, Carver College of Medicine, and.
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Glenn
authors.affiliation: Department of Molecular Physiology and Biophysics, the University of Iowa, Iowa City, Iowa 52242.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kawano
authors.affiliation: Department of Molecular Physiology and Biophysics, the University of Iowa, Iowa City, Iowa 52242.
authors.forename: N Charles
authors.identifier: 0000-0003-3287-4549
authors.initials: NC
authors.lastname: Harata
authors.affiliation: Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York 10029, and.
authors.forename: Michelle E
authors.initials: ME
authors.lastname: Ehrlich
authors.affiliation: Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104 pedro.gonzalez-alegre@uphs.upenn.edu.
authors.forename: Pedro
authors.identifier: 0000-0002-9887-2995
authors.initials: P
authors.lastname: Gonzalez-Alegre
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D020013:Calcium Signaling / Q000235:genetics; D002531:Cerebellum / Q000503:physiopathology; D004421:Dystonia / Q000235:genetics* / Q000503:physiopathology* / Q000523:psychology; D004721:Endoplasmic Reticulum / Q000235:genetics*; D059865:Endoplasmic Reticulum Stress / Q000235:genetics; D005786:Gene Expression Regulation / Q000235:genetics; D055879:Gene Knock-In Techniques; D005838:Genotype; D050956:HSP40 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D018832:Molecular Chaperones / Q000235:genetics*; D009474:Neurons / Q000502:physiology; D015398:Signal Transduction / Q000235:genetics
chemical_list: C494651:DNAJC3 protein, human; C491548:Dyt1 protein, mouse; D050956:HSP40 Heat-Shock Proteins; D018832:Molecular Chaperones; C108175:TOR1A protein, human
keywords: dystonia; eif2alpha; endoplasmic reticulum; p58; proteomics; torsina