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Thomsen M, Lange LM, Zech M, Lohmann K. Genetics and Pathogenesis of Dystonia. ANNUAL REVIEW OF PATHOLOGY 2024; 19:99-131. [PMID: 37738511 DOI: 10.1146/annurev-pathmechdis-051122-110756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/24/2023]
Abstract
Dystonia is a clinically and genetically highly heterogeneous neurological disorder characterized by abnormal movements and postures caused by involuntary sustained or intermittent muscle contractions. A number of groundbreaking genetic and molecular insights have recently been gained. While they enable genetic testing and counseling, their translation into new therapies is still limited. However, we are beginning to understand shared pathophysiological pathways and molecular mechanisms. It has become clear that dystonia results from a dysfunctional network involving the basal ganglia, cerebellum, thalamus, and cortex. On the molecular level, more than a handful of, often intertwined, pathways have been linked to pathogenic variants in dystonia genes, including gene transcription during neurodevelopment (e.g., KMT2B, THAP1), calcium homeostasis (e.g., ANO3, HPCA), striatal dopamine signaling (e.g., GNAL), endoplasmic reticulum stress response (e.g., EIF2AK2, PRKRA, TOR1A), autophagy (e.g., VPS16), and others. Thus, different forms of dystonia can be molecularly grouped, which may facilitate treatment development in the future.
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Affiliation(s)
- Mirja Thomsen
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany;
| | - Lara M Lange
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany;
| | - Michael Zech
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
| | - Katja Lohmann
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany;
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Fan Y, Si Z, Wang L, Zhang L. DYT- TOR1A dystonia: an update on pathogenesis and treatment. Front Neurosci 2023; 17:1216929. [PMID: 37638318 PMCID: PMC10448058 DOI: 10.3389/fnins.2023.1216929] [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: 05/04/2023] [Accepted: 07/24/2023] [Indexed: 08/29/2023] Open
Abstract
DYT-TOR1A dystonia is a neurological disorder characterized by involuntary muscle contractions and abnormal movements. It is a severe genetic form of dystonia caused by mutations in the TOR1A gene. TorsinA is a member of the AAA + family of adenosine triphosphatases (ATPases) involved in a variety of cellular functions, including protein folding, lipid metabolism, cytoskeletal organization, and nucleocytoskeletal coupling. Almost all patients with TOR1A-related dystonia harbor the same mutation, an in-frame GAG deletion (ΔGAG) in the last of its 5 exons. This recurrent variant results in the deletion of one of two tandem glutamic acid residues (i.e., E302/303) in a protein named torsinA [torsinA(△E)]. Although the mutation is hereditary, not all carriers will develop DYT-TOR1A dystonia, indicating the involvement of other factors in the disease process. The current understanding of the pathophysiology of DYT-TOR1A dystonia involves multiple factors, including abnormal protein folding, signaling between neurons and glial cells, and dysfunction of the protein quality control system. As there are currently no curative treatments for DYT-TOR1A dystonia, progress in research provides insight into its pathogenesis, leading to potential therapeutic and preventative strategies. This review summarizes the latest research advances in the pathogenesis, diagnosis, and treatment of DYT-TOR1A dystonia.
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Affiliation(s)
- Yuhang Fan
- Department of Neurology, the Second Hospital of Jilin University, Changchun, China
| | - Zhibo Si
- Department of Ophthalmology, the Second Hospital of Jilin University, Changchun, China
| | - Linlin Wang
- Department of Ultrasound, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Lei Zhang
- Department of Neurology, the Second Hospital of Jilin University, Changchun, China
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3
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Kruyer A, Parrilla-Carrero J, Powell C, Brandt L, Gutwinski S, Angelis A, Chalhoub RM, Jhou TC, Kalivas PW, Amato D. Accumbens D2-MSN hyperactivity drives antipsychotic-induced behavioral supersensitivity. Mol Psychiatry 2021; 26:6159-6169. [PMID: 34349226 PMCID: PMC8760070 DOI: 10.1038/s41380-021-01235-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 07/05/2021] [Accepted: 07/07/2021] [Indexed: 02/07/2023]
Abstract
Antipsychotic-induced dopamine supersensitivity, or behavioral supersensitivity, is a problematic consequence of long-term antipsychotic treatment characterized by the emergence of motor abnormalities, refractory symptoms, and rebound psychosis. The underlying mechanisms are unclear and no approaches exist to prevent or reverse these unwanted effects of antipsychotic treatment. Here we demonstrate that behavioral supersensitivity stems from long-lasting pre, post and perisynaptic plasticity, including insertion of Ca2+-permeable AMPA receptors and loss of D2 receptor-dependent inhibitory postsynaptic currents (IPSCs) in D2 receptor-expressing medium spiny neurons (D2-MSNs) in the nucleus accumbens core (NAcore). The resulting hyperexcitability, prominent in a subpopulation of D2-MSNs (21%), caused locomotor sensitization to cocaine and was associated with behavioral endophenotypes of antipsychotic treatment resistance and substance use disorder, including disrupted extinction learning and augmented cue-induced cocaine-seeking behavior. Chemogenetic restoration of IPSCs in D2-MSNs in the NAcore was sufficient to prevent antipsychotic-induced supersensitivity, pointing to an entirely novel therapeutic direction for overcoming this condition.
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Affiliation(s)
- Anna Kruyer
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | | | - Courtney Powell
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Lasse Brandt
- Department of Psychiatry and Psychotherapy, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Stefan Gutwinski
- Department of Psychiatry and Psychotherapy, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Ariana Angelis
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Reda M Chalhoub
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Thomas C Jhou
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Peter W Kalivas
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Davide Amato
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.
- Department of Psychiatry and Psychotherapy, Charité - Universitätsmedizin Berlin, Berlin, Germany.
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Staege S, Kutschenko A, Baumann H, Glaß H, Henkel L, Gschwendtberger T, Kalmbach N, Klietz M, Hermann A, Lohmann K, Seibler P, Wegner F. Reduced Expression of GABA A Receptor Alpha2 Subunit Is Associated With Disinhibition of DYT-THAP1 Dystonia Patient-Derived Striatal Medium Spiny Neurons. Front Cell Dev Biol 2021; 9:650586. [PMID: 34095114 PMCID: PMC8176025 DOI: 10.3389/fcell.2021.650586] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 04/08/2021] [Indexed: 12/18/2022] Open
Abstract
DYT-THAP1 dystonia (formerly DYT6) is an adolescent-onset dystonia characterized by involuntary muscle contractions usually involving the upper body. It is caused by mutations in the gene THAP1 encoding for the transcription factor Thanatos-associated protein (THAP) domain containing apoptosis-associated protein 1 and inherited in an autosomal-dominant manner with reduced penetrance. Alterations in the development of striatal neuronal projections and synaptic function are known from transgenic mice models. To investigate pathogenetic mechanisms, human induced pluripotent stem cell (iPSC)-derived medium spiny neurons (MSNs) from two patients and one family member with reduced penetrance carrying a mutation in the gene THAP1 (c.474delA and c.38G > A) were functionally characterized in comparison to healthy controls. Calcium imaging and quantitative PCR analysis revealed significantly lower Ca2+ amplitudes upon GABA applications and a marked downregulation of the gene encoding the GABAA receptor alpha2 subunit in THAP1 MSNs indicating a decreased GABAergic transmission. Whole-cell patch-clamp recordings showed a significantly lower frequency of miniature postsynaptic currents (mPSCs), whereas the frequency of spontaneous action potentials (APs) was elevated in THAP1 MSNs suggesting that decreased synaptic activity might have resulted in enhanced generation of APs. Our molecular and functional data indicate that a reduced expression of GABAA receptor alpha2 subunit could eventually lead to limited GABAergic synaptic transmission, neuronal disinhibition, and hyperexcitability of THAP1 MSNs. These data give pathophysiological insight and may contribute to the development of novel treatment strategies for DYT-THAP1 dystonia.
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Affiliation(s)
- Selma Staege
- Department of Neurology, Hannover Medical School, Hanover, Germany.,Center for Systems Neuroscience, Hanover, Germany
| | - Anna Kutschenko
- Department of Neurology, Hannover Medical School, Hanover, Germany
| | - Hauke Baumann
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Hannes Glaß
- Translational Neurodegeneration Section "Albrecht-Kossel", Department of Neurology, University of Rostock, Rostock, Germany
| | - Lisa Henkel
- Department of Neurology, Hannover Medical School, Hanover, Germany.,Center for Systems Neuroscience, Hanover, Germany
| | - Thomas Gschwendtberger
- Department of Neurology, Hannover Medical School, Hanover, Germany.,Center for Systems Neuroscience, Hanover, Germany
| | - Norman Kalmbach
- Department of Neurology, Hannover Medical School, Hanover, Germany
| | - Martin Klietz
- Department of Neurology, Hannover Medical School, Hanover, Germany
| | - Andreas Hermann
- Translational Neurodegeneration Section "Albrecht-Kossel", Department of Neurology, University of Rostock, Rostock, Germany.,German Center for Neurodegenerative Diseases Rostock/Greifswald, Rostock, Germany
| | - Katja Lohmann
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Philip Seibler
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Florian Wegner
- Department of Neurology, Hannover Medical School, Hanover, Germany.,Center for Systems Neuroscience, Hanover, Germany
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Kawano H, Mitchell SB, Koh JY, Goodman KM, Harata NC. Calcium-induced calcium release in noradrenergic neurons of the locus coeruleus. Brain Res 2020; 1729:146627. [PMID: 31883849 DOI: 10.1016/j.brainres.2019.146627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/19/2019] [Accepted: 12/24/2019] [Indexed: 12/11/2022]
Abstract
The locus coeruleus (LC) is a nucleus within the brainstem that consists of norepinephrine-releasing neurons. It is involved in broad processes including cognitive and emotional functions. Understanding the mechanisms that control the excitability of LC neurons is important because they innervate widespread brain regions. One of the key regulators is cytosolic calcium concentration ([Ca2+]c), the increases in which can be amplified by calcium-induced calcium release (CICR) from intracellular calcium stores. Although the electrical activities of LC neurons are regulated by changes in [Ca2+]c, the extent of CICR involvement in this regulation has remained unclear. Here we show that CICR hyperpolarizes acutely dissociated LC neurons of the rat and demonstrate the underlying pathway. When CICR was activated by extracellular application of 10 mM caffeine, LC neurons were hyperpolarized in the current-clamp mode of patch-clamp recording, and the majority of neurons showed an outward current in the voltage-clamp mode. This outward current was accompanied by increased membrane conductance, and its reversal potential was close to the K+ equilibrium potential, indicating that it is mediated by opening of K+ channels. The outward current was generated in the absence of extracellular calcium and was blocked when the calcium stores were inhibited by applying ryanodine. Pharmacological blockers indicated that it was mediated by Ca2+-activated K+ channels of the non-small conductance type. The application of caffeine increased [Ca2+]c, as visualized by fluorescence microscopy. These findings show CICR suppresses LC neuronal activity, and indicate its dynamic role in modulating the LC-mediated noradrenergic tone in the brain.
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Affiliation(s)
- Hiroyuki Kawano
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Sara B Mitchell
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Jin-Young Koh
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Molecular Otolaryngology and Renal Research Laboratories, Department of Otolaryngology-Head and Neck Surgery, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Biomedical Engineering, University of Iowa College of Engineering, Iowa City, IA, USA
| | - Kirsty M Goodman
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Biology & Biochemistry, University of Bath, Bath, UK
| | - N Charles Harata
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
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Haddar M, Uno K, Hamatani K, Muramatsu SI, Nitta A. Regulatory system of mGluR group II in the nucleus accumbens for methamphetamine-induced dopamine increase by the medial prefrontal cortex. Neuropsychopharmacol Rep 2019; 39:209-216. [PMID: 31283871 PMCID: PMC7292294 DOI: 10.1002/npr2.12068] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 01/11/2023] Open
Abstract
AIM We previously reported that methamphetamine (METH)-induced conditioned place preference was attenuated by Shati/Nat8l overexpression in the medial prefrontal cortex (mPFC). Shati/Nat8l overexpression in the mPFC expressed lower levels of both glutamate and dopamine (DA) in the nucleus accumbens (NAc) and attenuated METH-induced DA elevation. We suggested a mechanism in which a decline of glutamate levels in the NAc decreases extracellular DA levels. However, the hypothesis has not confirmed. METHODS We conducted a recovery experiments by pre-microinjection of an mGluR group II antagonist, LY341495, into the NAc shell of mPFC-Shati/Nat8l-overexpressed mice followed by METH injection and DA levels measurement by in vivo microdialysis. RESULTS Pretreatment with LY341495 was able to restore METH-induced DA increase. Furthermore, mice injected with an adeno-associated virus vector containing GFP (AAV-GFP vector) in the mPFC expressed a colocalization of GFP with DARPP-32 a medium spiny neuron (MSN) marker. Next, co-immunostaining of DARPP-32 and neuronal nitric oxide synthase (nNOS: expressed in a subtype of gamma-Aminobutyric acid (GABA interneurons) in ventral tegmental area (VTA) showed a colocalization of nNOS and DARPP-32. CONCLUSION These results provided a proof that Shati/Nat8l attenuation of METH-induced DA increase is mediated by mGluR group II in the NAc. Moreover, immunohistochemical study showed a direct connection of mPFC projection neurons with NAc MSN and a connection of MSN projection neurons with a subtype of GABA interneurons in VTA.
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Affiliation(s)
- Meriem Haddar
- Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Kyosuke Uno
- Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.,Laboratory of Molecular Pharmacology, Faculty of Pharmaceutical Sciences, Setsunan University, Hirakata, Japan
| | - Kohei Hamatani
- Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Shin-Ichi Muramatsu
- Division of Neurological Gene Therapy, Open Inovation Center, Jichi Medical University, Shimotsuke, Japan.,Center for Gene & Cell Therapy, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Atsumi Nitta
- Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
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Gonzalez-Alegre P. Advances in molecular and cell biology of dystonia: Focus on torsinA. Neurobiol Dis 2019; 127:233-241. [DOI: 10.1016/j.nbd.2019.03.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 02/20/2019] [Accepted: 03/09/2019] [Indexed: 12/15/2022] Open
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Mitchell SB, Iwabuchi S, Kawano H, Yuen TMT, Koh JY, Ho KWD, Harata NC. Structure of the Golgi apparatus is not influenced by a GAG deletion mutation in the dystonia-associated gene Tor1a. PLoS One 2018; 13:e0206123. [PMID: 30403723 PMCID: PMC6221310 DOI: 10.1371/journal.pone.0206123] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 10/08/2018] [Indexed: 12/14/2022] Open
Abstract
Autosomal-dominant, early-onset DYT1 dystonia is associated with an in-frame deletion of a glutamic acid codon (ΔE) in the TOR1A gene. The gene product, torsinA, is an evolutionarily conserved AAA+ ATPase. The fact that constitutive secretion from patient fibroblasts is suppressed indicates that the ΔE-torsinA protein influences the cellular secretory machinery. However, which component is affected remains unclear. Prompted by recent reports that abnormal protein trafficking through the Golgi apparatus, the major protein-sorting center of the secretory pathway, is sometimes associated with a morphological change in the Golgi, we evaluated the influence of ΔE-torsinA on this organelle. Specifically, we examined its structure by confocal microscopy, in cultures of striatal, cerebral cortical and hippocampal neurons obtained from wild-type, heterozygous and homozygous ΔE-torsinA knock-in mice. In live neurons, the Golgi was assessed following uptake of a fluorescent ceramide analog, and in fixed neurons it was analyzed by immuno-fluorescence staining for the Golgi-marker GM130. Neither staining method indicated genotype-specific differences in the size, staining intensity, shape or localization of the Golgi. Moreover, no genotype-specific difference was observed as the neurons matured in vitro. These results were supported by a lack of genotype-specific differences in GM130 expression levels, as assessed by Western blotting. The Golgi was also disrupted by treatment with brefeldin A, but no genotype-specific differences were found in the immuno-fluorescence staining intensity of GM130. Overall, our results demonstrate that the ΔE-torsinA protein does not drastically influence Golgi morphology in neurons, irrespective of genotype, brain region (among those tested), or maturation stage in culture. While it remains possible that functional changes in the Golgi exist, our findings imply that any such changes are not severe enough to influence its morphology to a degree detectable by light microscopy.
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Affiliation(s)
- Sara B. Mitchell
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Sadahiro Iwabuchi
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Hiroyuki Kawano
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Tsun Ming Tom Yuen
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
- Department of Chemical and Biochemical Engineering, University of Iowa College of Engineering, Iowa City, Iowa, United States of America
| | - Jin-Young Koh
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - K. W. David Ho
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
- Medical Scientist Training Program, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - N. Charles Harata
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
- Medical Scientist Training Program, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
- Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
- * E-mail:
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Disruption of Protein Processing in the Endoplasmic Reticulum of DYT1 Knock-in Mice Implicates Novel Pathways in Dystonia Pathogenesis. J Neurosci 2017; 36:10245-10256. [PMID: 27707963 DOI: 10.1523/jneurosci.0669-16.2016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 07/13/2016] [Indexed: 11/21/2022] Open
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. SIGNIFICANCE STATEMENT 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.
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Domingo A, Erro R, Lohmann K. Novel Dystonia Genes: Clues on Disease Mechanisms and the Complexities of High-Throughput Sequencing. Mov Disord 2016; 31:471-7. [PMID: 26991507 DOI: 10.1002/mds.26600] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 02/08/2016] [Accepted: 02/11/2016] [Indexed: 12/24/2022] Open
Abstract
Dystonia is a genetically heterogenous disease and a prototype disorder where next-generation sequencing has facilitated the identification of new pathogenic genes. This includes the first two genes linked to recessively inherited isolated dystonia, that is, HPCA (hippocalcin) and COL6A3 (collagen VI alpha 3). These genes are proposed to underlie cases of the so-called DYT2-like dystonia, while also reiterating two distinct pathways in dystonia pathogenesis. First, deficiency in HPCA function is thought to alter calcium homeostasis, a mechanism that has previously been forwarded for CACNA1A and ANO3. The novel myoclonus-dystonia genes KCTD17 and CACNA1B also implicate abnormal calcium signaling in dystonia. Second, the phenotype in COL6A3-loss-of-function zebrafish models argues for a neurodevelopmental defect, which has previously been suggested as a possible biological mechanism for THAP1, TOR1A, and TAF1 based on expression data. The newly reported myoclonus-dystonia gene, RELN, plays also a role in the formation of brain structures. Defects in neurodevelopment likewise seem to be a recurrent scheme underpinning mainly complex dystonias, for example those attributable to biallelic mutations in GCH1, TH, SPR, or to heterozygous TUBB4A mutations. To date, it remains unclear whether dystonia is a common phenotypic outcome of diverse underlying disease mechanisms, or whether the different genetic causes converge in a single pathway. Importantly, the relevance of pathways highlighted by novel dystonia genes identified by high-throughput sequencing depends on the confirmation of mutation pathogenicity in subsequent genetic and functional studies. However, independent, careful validation of genetic findings lags behind publications of newly identified genes. We conclude with a discussion on the characteristics of true-positive reports.
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Affiliation(s)
- Aloysius Domingo
- Institute of Neurogenetics, University of Luebeck, Luebeck, Germany
| | - Roberto Erro
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, United Kingdom
- Dipartimento di Scienze Neurologiche e del Movimento, Università di Verona, Verona, Italy
| | - Katja Lohmann
- Institute of Neurogenetics, University of Luebeck, Luebeck, Germany
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Koh JY, Iwabuchi S, Huang Z, Harata NC. Rapid genotyping of animals followed by establishing primary cultures of brain neurons. J Vis Exp 2015. [PMID: 25742545 DOI: 10.3791/51879] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
High-resolution analysis of the morphology and function of mammalian neurons often requires the genotyping of individual animals followed by the analysis of primary cultures of neurons. We describe a set of procedures for: labeling newborn mice to be genotyped, rapid genotyping, and establishing low-density cultures of brain neurons from these mice. Individual mice are labeled by tattooing, which allows for long-term identification lasting into adulthood. Genotyping by the described protocol is fast and efficient, and allows for automated extraction of nucleic acid with good reliability. This is useful under circumstances where sufficient time for conventional genotyping is not available, e.g., in mice that suffer from neonatal lethality. Primary neuronal cultures are generated at low density, which enables imaging experiments at high spatial resolution. This culture method requires the preparation of glial feeder layers prior to neuronal plating. The protocol is applied in its entirety to a mouse model of the movement disorder DYT1 dystonia (ΔE-torsinA knock-in mice), and neuronal cultures are prepared from the hippocampus, cerebral cortex and striatum of these mice. This protocol can be applied to mice with other genetic mutations, as well as to animals of other species. Furthermore, individual components of the protocol can be used for isolated sub-projects. Thus this protocol will have wide applications, not only in neuroscience but also in other fields of biological and medical sciences.
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Affiliation(s)
- Jin-Young Koh
- Department of Molecular Physiology & Biophysics, University of Iowa Carver College of Medicine; Department of Psychiatry, University of Iowa Carver College of Medicine
| | - Sadahiro Iwabuchi
- Department of Molecular Physiology & Biophysics, University of Iowa Carver College of Medicine
| | | | - N Charles Harata
- Department of Molecular Physiology & Biophysics, University of Iowa Carver College of Medicine;
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Genetic animal models of dystonia: common features and diversities. Prog Neurobiol 2014; 121:91-113. [PMID: 25034123 DOI: 10.1016/j.pneurobio.2014.07.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 06/06/2014] [Accepted: 07/03/2014] [Indexed: 01/13/2023]
Abstract
Animal models are pivotal for studies of pathogenesis and treatment of disorders of the central nervous system which in its complexity cannot yet be modeled in vitro or using computer simulations. The choice of a specific model to test novel therapeutic strategies for a human disease should be based on validity of the model for the approach: does the model reflect symptoms, pathogenesis and treatment response present in human patients? In the movement disorder dystonia, prior to the availability of genetically engineered mice, spontaneous mutants were chosen based on expression of dystonic features, including abnormal muscle contraction, movements and postures. Recent discovery of a number of genes and gene products involved in dystonia initiated research on pathogenesis of the disorder, and the creation of novel models based on gene mutations. Here we present a review of current models of dystonia, with a focus on genetic rodent models, which will likely be first choice in the future either for pathophysiological or for preclinical drug testing or both. In order to help selection of a model depending on expression of a specific feature of dystonia, this review is organized by symptoms and current knowledge of pathogenesis of dystonia. We conclude that albeit there is increasing need for research on pathogenesis of the disease and development of improved models, current models do replicate features of dystonia and are useful tools to develop urgently demanded treatment for this debilitating disorder.
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