1
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Thumbadoo KM, Dieriks BV, Murray HC, Swanson MEV, Yoo JH, Mehrabi NF, Turner C, Dragunow M, Faull RLM, Curtis MA, Siddique T, Shaw CE, Newell KL, Henden L, Williams KL, Nicholson GA, Scotter EL. Hippocampal aggregation signatures of pathogenic UBQLN2 in amyotrophic lateral sclerosis and frontotemporal dementia. Brain 2024; 147:3547-3561. [PMID: 38703371 PMCID: PMC11449146 DOI: 10.1093/brain/awae140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 03/03/2024] [Accepted: 03/07/2024] [Indexed: 05/06/2024] Open
Abstract
Pathogenic variants in the UBQLN2 gene cause X-linked dominant amyotrophic lateral sclerosis and/or frontotemporal dementia characterized by ubiquilin 2 aggregates in neurons of the motor cortex, hippocampus and spinal cord. However, ubiquilin 2 neuropathology is also seen in sporadic and familial amyotrophic lateral sclerosis and/or frontotemporal dementia cases not caused by UBQLN2 pathogenic variants, particularly C9orf72-linked cases. This makes the mechanistic role of mutant ubiquilin 2 protein and the value of ubiquilin 2 pathology for predicting genotype unclear. Here we examine a cohort of 44 genotypically diverse amyotrophic lateral sclerosis cases with or without frontotemporal dementia, including eight cases with UBQLN2 variants [resulting in p.S222G, p.P497H, p.P506S, p.T487I (two cases) and p.P497L (three cases)]. Using multiplexed (five-label) fluorescent immunohistochemistry, we mapped the co-localization of ubiquilin 2 with phosphorylated TDP-43, dipeptide repeat aggregates and p62 in the hippocampus of controls (n = 6), or amyotrophic lateral sclerosis with or without frontotemporal dementia in sporadic (n = 20), unknown familial (n = 3), SOD1-linked (n = 1), FUS-linked (n = 1), C9orf72-linked (n = 5) and UBQLN2-linked (n = 8) cases. We differentiate between (i) ubiquilin 2 aggregation together with phosphorylated TDP-43 or dipeptide repeat proteins; and (ii) ubiquilin 2 self-aggregation promoted by UBQLN2 pathogenic variants that cause amyotrophic lateral sclerosis and/or frontotemporal dementia. Overall, we describe a hippocampal protein aggregation signature that fully distinguishes mutant from wild-type ubiquilin 2 in amyotrophic lateral sclerosis with or without frontotemporal dementia, whereby mutant ubiquilin 2 is more prone than wild-type to aggregate independently of driving factors. This neuropathological signature can be used to assess the pathogenicity of UBQLN2 gene variants and to understand the mechanisms of UBQLN2-linked disease.
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Affiliation(s)
- Kyrah M Thumbadoo
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
- Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
| | - Birger V Dieriks
- Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland 1010, New Zealand
| | - Helen C Murray
- Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland 1010, New Zealand
| | - Molly E V Swanson
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland 1010, New Zealand
| | - Ji Hun Yoo
- Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
- Department of Pharmacology and Clinical Pharmacology, University of Auckland, Auckland 1010, New Zealand
| | - Nasim F Mehrabi
- Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland 1010, New Zealand
| | - Clinton Turner
- Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland 1010, New Zealand
- Department of Anatomical Pathology, LabPlus, Auckland City Hospital, Auckland 1010, New Zealand
| | - Michael Dragunow
- Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
- Department of Pharmacology and Clinical Pharmacology, University of Auckland, Auckland 1010, New Zealand
| | - Richard L M Faull
- Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland 1010, New Zealand
| | - Maurice A Curtis
- Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland 1010, New Zealand
| | - Teepu Siddique
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Christopher E Shaw
- Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
- UK Dementia Research Institute Centre, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, UK
| | - Kathy L Newell
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Lyndal Henden
- Macquarie University Motor Neuron Disease Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Kelly L Williams
- Macquarie University Motor Neuron Disease Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Garth A Nicholson
- Macquarie University Motor Neuron Disease Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
- Northcott Neuroscience Laboratory, Australian and New Zealand Army Corps (ANZAC) Research Institute, Concord, New South Wales 2139, Australia
- Faculty of Medicine, University of Sydney, Sydney, New South Wales 2050, Australia
- Molecular Medicine Laboratory, Concord Repatriation General Hospital, Concord, New South Wales 2139, Australia
| | - Emma L Scotter
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
- Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
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2
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Bagyinszky E, Hulme J, An SSA. Studies of Genetic and Proteomic Risk Factors of Amyotrophic Lateral Sclerosis Inspire Biomarker Development and Gene Therapy. Cells 2023; 12:1948. [PMID: 37566027 PMCID: PMC10417729 DOI: 10.3390/cells12151948] [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: 06/21/2023] [Revised: 07/21/2023] [Accepted: 07/25/2023] [Indexed: 08/12/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease affecting the upper and lower motor neurons, leading to muscle weakness, motor impairments, disabilities and death. Approximately 5-10% of ALS cases are associated with positive family history (familial ALS or fALS), whilst the remainder are sporadic (sporadic ALS, sALS). At least 50 genes have been identified as causative or risk factors for ALS. Established pathogenic variants include superoxide dismutase type 1 (SOD1), chromosome 9 open reading frame 72 (c9orf72), TAR DNA Binding Protein (TARDBP), and Fused In Sarcoma (FUS); additional ALS-related genes including Charged Multivesicular Body Protein 2B (CHMP2B), Senataxin (SETX), Sequestosome 1 (SQSTM1), TANK Binding Kinase 1 (TBK1) and NIMA Related Kinase 1 (NEK1), have been identified. Mutations in these genes could impair different mechanisms, including vesicle transport, autophagy, and cytoskeletal or mitochondrial functions. So far, there is no effective therapy against ALS. Thus, early diagnosis and disease risk predictions remain one of the best options against ALS symptomologies. Proteomic biomarkers, microRNAs, and extracellular vehicles (EVs) serve as promising tools for disease diagnosis or progression assessment. These markers are relatively easy to obtain from blood or cerebrospinal fluids and can be used to identify potential genetic causative and risk factors even in the preclinical stage before symptoms appear. In addition, antisense oligonucleotides and RNA gene therapies have successfully been employed against other diseases, such as childhood-onset spinal muscular atrophy (SMA), which could also give hope to ALS patients. Therefore, an effective gene and biomarker panel should be generated for potentially "at risk" individuals to provide timely interventions and better treatment outcomes for ALS patients as soon as possible.
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Affiliation(s)
- Eva Bagyinszky
- Graduate School of Environment Department of Industrial and Environmental Engineering, Gachon University, Seongnam-si 13120, Republic of Korea;
| | - John Hulme
- Graduate School of Environment Department of Industrial and Environmental Engineering, Gachon University, Seongnam-si 13120, Republic of Korea;
| | - Seong Soo A. An
- Department of Bionano Technology, Gachon University, Seongnam-si 13120, Republic of Korea
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3
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Idera A, Sharkey LM, Kurauchi Y, Kadoyama K, Paulson HL, Katsuki H, Seki T. Wild-type and pathogenic forms of ubiquilin 2 differentially modulate components of the autophagy-lysosome pathways. J Pharmacol Sci 2023; 152:182-192. [PMID: 37257946 DOI: 10.1016/j.jphs.2023.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/14/2023] [Accepted: 05/08/2023] [Indexed: 06/02/2023] Open
Abstract
Missense mutations of ubiquilin 2 (UBQLN2) have been identified to cause X-linked amyotrophic lateral sclerosis (ALS). Proteasome-mediated protein degradation is reported to be impaired by ALS-associated mutations of UBQLN2. However, it remains unknown how these mutations affect autophagy-lysosome protein degradation, which consists of macroautophagy (MA), microautophagy (mA), and chaperone-mediated autophagy (CMA). Using a CMA/mA fluorescence reporter we found that overexpression of wild-type UBQLN2 impairs CMA. Conversely, knockdown of endogenous UBQLN2 increases CMA activity, suggesting that normally UBQLN2 negatively regulates CMA. ALS-associated mutant forms of UBQLN2 exacerbate this impairment of CMA. Using cells stably transfected with wild-type or ALS-associated mutant UBQLN2, we further determined that wild-type UBQLN2 increased the ratio of LAMP2A (a CMA-related protein) to LAMP1 (a lysosomal protein). This could represent a compensatory reaction to the impairment of CMA by wild-type UBQLN2. However, ALS-associated mutant UBQLN2 failed to show this compensation, exacerbating the impairment of CMA by mutant UBQLN2. We further demonstrated that ALS-associated mutant forms of UBQLN2 also impair MA, but wild-type UBQLN2 does not. These results support the view that ALS-associated mutant forms of UBQLN2 impair both CMA and MA which may contribute to the neurodegeneration observed in patients with UBQLN2-mediated ALS.
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Affiliation(s)
- Akiko Idera
- Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Lisa M Sharkey
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Yuki Kurauchi
- Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Keiichi Kadoyama
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Japan
| | - Henry L Paulson
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Hiroshi Katsuki
- Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Takahiro Seki
- Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan; Department of Pharmacology, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Japan.
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4
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Patel RB, Bajpai AK, Thirumurugan K. Differential Expression of MicroRNAs and Predicted Drug Target in Amyotrophic Lateral Sclerosis. J Mol Neurosci 2023; 73:375-390. [PMID: 37249795 DOI: 10.1007/s12031-023-02124-z] [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: 02/17/2023] [Accepted: 05/18/2023] [Indexed: 05/31/2023]
Abstract
ALS (Amyotrophic Lateral Sclerosis) is a rare type of neurodegenerative disease. It shows progressive degradation of motor neurons in the brain and spinal cord. At present, there is no treatment available that can completely cure ALS. The available treatments can only increase a patient's life span by a few months. Recently, microRNAs (miRNAs), a sub-class of small non-coding RNAs have been shown to play an essential role in the diagnosis, prognosis, and therapy of ALS. Our study focuses on analyzing differential miRNA profiles and predicting drug targets in ALS using bioinformatics and computational approach. The study identifies eight highly differentially expressed miRNAs in ALS patients, four of which are novel. We identified 42 hub genes for these eight highly expressed miRNAs with Amyloid Precursor Protein (APP) as a candidate gene among them for highly expressed down-regulated miRNA, hsa-miR-455-3p using protein-protein interaction network and Cytoscape analysis. A novel association has been found between hsa-miR-455-3p/APP/serotonergic pathway using KEGG pathway analysis. Also, molecular docking studies have revealed curcumin as a potential drug target that may be used for the treatment of ALS. Thus, the present study has identified four novel miRNA biomarkers: hsa-miR-3613-5p, hsa-miR-24, hsa-miR-3064-5p, and hsa-miR-4455. There is a formation of a novel axis, hsa-miR-455-3p/APP/serotonergic pathway, and curcumin is predicted as a potential drug target for ALS.
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Affiliation(s)
- Riya Ben Patel
- #412J, Structural Biology Lab, Pearl Research Park, School of Biosciences & Technology, Vellore Institute of Technology, Vellore-632014, India
| | - Akhilesh Kumar Bajpai
- Department of Genetics, Genomics, and Informatics, University of Tennessee Health Science Center, Memphis, TN, 38163, USA.
| | - Kavitha Thirumurugan
- #412J, Structural Biology Lab, Pearl Research Park, School of Biosciences & Technology, Vellore Institute of Technology, Vellore-632014, India.
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5
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Black HH, Hanson JL, Roberts JE, Leslie SN, Campodonico W, Ebmeier CC, Holling GA, Tay JW, Matthews AM, Ung E, Lau CI, Whiteley AM. UBQLN2 restrains the domesticated retrotransposon PEG10 to maintain neuronal health in ALS. eLife 2023; 12:e79452. [PMID: 36951542 PMCID: PMC10076021 DOI: 10.7554/elife.79452] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 03/15/2023] [Indexed: 03/24/2023] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive motor neuron dysfunction and loss. A portion of ALS cases are caused by mutation of the proteasome shuttle factor Ubiquilin 2 (UBQLN2), but the molecular pathway leading from UBQLN2 dysfunction to disease remains unclear. Here, we demonstrate that UBQLN2 regulates the domesticated gag-pol retrotransposon 'paternally expressed gene 10 (PEG10)' in human cells and tissues. In cells, the PEG10 gag-pol protein cleaves itself in a mechanism reminiscent of retrotransposon self-processing to generate a liberated 'nucleocapsid' fragment, which uniquely localizes to the nucleus and changes the expression of genes involved in axon remodeling. In spinal cord tissue from ALS patients, PEG10 gag-pol is elevated compared to healthy controls. These findings implicate the retrotransposon-like activity of PEG10 as a contributing mechanism in ALS through the regulation of gene expression, and restraint of PEG10 as a primary function of UBQLN2.
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Affiliation(s)
- Holly H Black
- Department of Biochemistry, University of Colorado BoulderBoulderUnited States
| | - Jessica L Hanson
- Institute for Behavioral Genetics, University of Colorado BoulderBoulderUnited States
| | - Julia E Roberts
- Department of Biochemistry, University of Colorado BoulderBoulderUnited States
| | - Shannon N Leslie
- Department of Biochemistry, University of Colorado BoulderBoulderUnited States
| | - Will Campodonico
- Department of Biochemistry, University of Colorado BoulderBoulderUnited States
| | | | - G Aaron Holling
- Department of Biochemistry, University of Colorado BoulderBoulderUnited States
| | - Jian Wei Tay
- Biofrontiers Institute, University of Colorado BoulderBoulderUnited States
| | - Autumn M Matthews
- Department of Biochemistry, University of Colorado BoulderBoulderUnited States
| | - Elizabeth Ung
- Department of Biochemistry, University of Colorado BoulderBoulderUnited States
| | - Cristina I Lau
- Department of Biochemistry, University of Colorado BoulderBoulderUnited States
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6
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Phung TH, Tatman M, Monteiro MJ. UBQLN2 undergoes a reversible temperature-induced conformational switch that regulates binding with HSPA1B: ALS/FTD mutations cripple the switch but do not destroy HSPA1B binding. Biochim Biophys Acta Gen Subj 2023; 1867:130284. [PMID: 36423739 PMCID: PMC9792439 DOI: 10.1016/j.bbagen.2022.130284] [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: 07/15/2022] [Revised: 10/23/2022] [Accepted: 11/18/2022] [Indexed: 11/23/2022]
Abstract
Here we present evidence, based on alterations of its intrinsic tryptophan fluorescence, that UBQLN2 protein undergoes a conformational switch when the temperature is raised from 37 °C to 42 °C. The switch is reset on restoration of the temperature. We speculate that the switch regulates UBQLN2 function in the heat shock response because elevation of the temperature from 37 °C to 42 °C dramatically increased in vitro binding between UBQLN2 and HSPA1B. Furthermore, restoration of the temperature to 37 °C decreased HSPA1B binding. By comparison to wild type (WT) UBQLN2, we found that all five ALS/FTD mutant UBQLN2 proteins we examined had attenuated alterations in tryptophan fluorescence when shifted to 42 °C, suggesting that the conformational switch is crippled in the mutants. Paradoxically, all five mutants bound similar amounts of HSPA1B compared to WT UBQLN2 protein at 42 °C, suggesting that either the conformational switch is not instrumental for HSPA1B binding, or that, although damaged, it is still functional. Comparison of the poly-ubiquitin chain binding revealed that WT UBQLN2 binds more avidly with K63 than with K48 chains. The avidity may explain the involvement of UBQLN2 in autophagy and cell signaling. Consistent with its function in autophagy, we found UBQLN2 binds directly with LC3, the autophagosomal-specific membrane-tethered protein. Finally, we provide evidence that WT UBQLN2 can homodimerize, and heterodimerize with WT UBQLN1. We show that ALS mutant P497S-UBQLN2 protein can oligomerize with either WT UBQLN1 or 2, providing a possible mechanism for how mutant UBQLN2 proteins could bind and inactivate UBQLN proteins, causing loss of function.
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Affiliation(s)
- Trong H Phung
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Micaela Tatman
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Mervyn J Monteiro
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA.
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7
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Huseby CJ, Delvaux E, Brokaw DL, Coleman PD. Blood RNA transcripts reveal similar and differential alterations in fundamental cellular processes in Alzheimer's disease and other neurodegenerative diseases. Alzheimers Dement 2022. [DOI: 10.1002/alz.12880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 09/30/2022] [Accepted: 10/21/2022] [Indexed: 12/24/2022]
Affiliation(s)
- Carol J. Huseby
- ASU‐Banner Neurodegenerative Disease Research Center Arizona State University Tempe Arizona USA
| | - Elaine Delvaux
- ASU‐Banner Neurodegenerative Disease Research Center Arizona State University Tempe Arizona USA
| | - Danielle L. Brokaw
- University of Pennsylvania Perelman School of Medicine Philadelphia Pennsylvania USA
| | - Paul D. Coleman
- ASU‐Banner Neurodegenerative Disease Research Center Arizona State University Tempe Arizona USA
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8
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Strohm L, Hu Z, Suk Y, Rühmkorf A, Sternburg E, Gattringer V, Riemenschneider H, Berutti R, Graf E, Weishaupt JH, Brill MS, Harbauer AB, Dormann D, Dengjel J, Edbauer D, Behrends C. Multi-omics profiling identifies a deregulated FUS-MAP1B axis in ALS/FTD-associated UBQLN2 mutants. Life Sci Alliance 2022; 5:5/11/e202101327. [PMID: 35777956 PMCID: PMC9258132 DOI: 10.26508/lsa.202101327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 06/10/2022] [Accepted: 06/14/2022] [Indexed: 11/24/2022] Open
Abstract
Analysis of ALS patient-derived and engineered cells revealed that mutant UBQLN2 increases mRNA and protein of MAP1B which is mediated by dephosphorylation of FUS within its RNA-binding domain. Ubiquilin-2 (UBQLN2) is a ubiquitin-binding protein that shuttles ubiquitinated proteins to proteasomal and autophagic degradation. UBQLN2 mutations are genetically linked to the neurodegenerative disorders amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD). However, it remains elusive how UBQLN2 mutations cause ALS/FTD. Here, we systematically examined proteomic and transcriptomic changes in patient-derived lymphoblasts and CRISPR/Cas9–engineered HeLa cells carrying ALS/FTD UBQLN2 mutations. This analysis revealed a strong up-regulation of the microtubule-associated protein 1B (MAP1B) which was also observed in UBQLN2 knockout cells and primary rodent neurons depleted of UBQLN2, suggesting that a UBQLN2 loss-of-function mechanism is responsible for the elevated MAP1B levels. Consistent with MAP1B’s role in microtubule binding, we detected an increase in total and acetylated tubulin. Furthermore, we uncovered that UBQLN2 mutations result in decreased phosphorylation of MAP1B and of the ALS/FTD–linked fused in sarcoma (FUS) protein at S439 which is critical for regulating FUS-RNA binding and MAP1B protein abundance. Together, our findings point to a deregulated UBQLN2-FUS-MAP1B axis that may link protein homeostasis, RNA metabolism, and cytoskeleton dynamics, three molecular pathomechanisms of ALS/FTD.
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Affiliation(s)
- Laura Strohm
- Munich Cluster for Systems Neurology, Medical Faculty, Ludwig-Maximilians-University München, Munich, Germany
| | - Zehan Hu
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Yongwon Suk
- Institute for Molecular Physiology, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Alina Rühmkorf
- Max Planck Institute of Neurobiology, Martinsried, Germany
| | - Erin Sternburg
- Institute for Molecular Physiology, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Vanessa Gattringer
- Munich Cluster for Systems Neurology, Medical Faculty, Ludwig-Maximilians-University München, Munich, Germany
| | - Henrick Riemenschneider
- Munich Cluster for Systems Neurology, Medical Faculty, Ludwig-Maximilians-University München, Munich, Germany.,German Center for Neurodegenerative Diseases Munich, Munich, Germany
| | - Riccardo Berutti
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Elisabeth Graf
- Institut für Humangenetik, Klinikum Rechts der Isar der Technischen Universität München, Munich, Germany
| | - Jochen H Weishaupt
- Division of Neurodegenerative Disorders, Department of Neurology, Medical Faculty Mannheim, Mannheim Center for Translational Neurosciences, Heidelberg University, Mannheim, Germany
| | | | - Angelika B Harbauer
- Institute of Neuronal Cell Biology, Technical University of Munich, Munich, Germany.,Max Planck Institute of Neurobiology, Martinsried, Germany.,Munich Cluster for Systems Neurology, Munich, Germany
| | - Dorothee Dormann
- Institute for Molecular Physiology, Johannes Gutenberg-University Mainz, Mainz, Germany.,Institute of Molecule Biology, Mainz, Germany
| | - Jörn Dengjel
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Dieter Edbauer
- Munich Cluster for Systems Neurology, Medical Faculty, Ludwig-Maximilians-University München, Munich, Germany.,German Center for Neurodegenerative Diseases Munich, Munich, Germany
| | - Christian Behrends
- Munich Cluster for Systems Neurology, Medical Faculty, Ludwig-Maximilians-University München, Munich, Germany
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9
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Lin BC, Higgins NR, Phung TH, Monteiro MJ. UBQLN proteins in health and disease with a focus on UBQLN2 in ALS/FTD. FEBS J 2022; 289:6132-6153. [PMID: 34273246 PMCID: PMC8761781 DOI: 10.1111/febs.16129] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/08/2021] [Accepted: 07/16/2021] [Indexed: 01/12/2023]
Abstract
Ubiquilin (UBQLN) proteins are a dynamic and versatile family of proteins found in all eukaryotes that function in the regulation of proteostasis. Besides their canonical function as shuttle factors in delivering misfolded proteins to the proteasome and autophagy systems for degradation, there is emerging evidence that UBQLN proteins play broader roles in proteostasis. New information suggests the proteins function as chaperones in protein folding, protecting proteins prior to membrane insertion, and as guardians for mitochondrial protein import. In this review, we describe the evidence for these different roles, highlighting how different domains of the proteins impart these functions. We also describe how changes in the structure and phase separation properties of UBQLNs may regulate their activity and function. Finally, we discuss the pathogenic mechanisms by which mutations in UBQLN2 cause amyotrophic lateral sclerosis and frontotemporal dementia. We describe the animal model systems made for different UBQLN2 mutations and how lessons learnt from these systems provide fundamental insight into the molecular mechanisms by which UBQLN2 mutations drive disease pathogenesis through disturbances in proteostasis.
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Affiliation(s)
- Brian C. Lin
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA,Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Nicole R. Higgins
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA,Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Trong H. Phung
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Mervyn J. Monteiro
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA,Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA,Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
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10
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Cozzi M, Ferrari V. Autophagy Dysfunction in ALS: from Transport to Protein Degradation. J Mol Neurosci 2022; 72:1456-1481. [PMID: 35708843 PMCID: PMC9293831 DOI: 10.1007/s12031-022-02029-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 05/17/2022] [Indexed: 01/18/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease affecting upper and lower motor neurons (MNs). Since the identification of the first ALS mutation in 1993, more than 40 genes have been associated with the disorder. The most frequent genetic causes of ALS are represented by mutated genes whose products challenge proteostasis, becoming unable to properly fold and consequently aggregating into inclusions that impose proteotoxic stress on affected cells. In this context, increasing evidence supports the central role played by autophagy dysfunctions in the pathogenesis of ALS. Indeed, in early stages of disease, high levels of proteins involved in autophagy are present in ALS MNs; but at the same time, with neurodegeneration progression, autophagy-mediated degradation decreases, often as a result of the accumulation of toxic protein aggregates in affected cells. Autophagy is a complex multistep pathway that has a central role in maintaining cellular homeostasis. Several proteins are involved in its tight regulation, and importantly a relevant fraction of ALS-related genes encodes products that directly take part in autophagy, further underlining the relevance of this key protein degradation system in disease onset and progression. In this review, we report the most relevant findings concerning ALS genes whose products are involved in the several steps of the autophagic pathway, from phagophore formation to autophagosome maturation and transport and finally to substrate degradation.
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Affiliation(s)
- Marta Cozzi
- Dipartimento Di Scienze Farmacologiche E Biomolecolari, Università Degli Studi Di Milano, 20133, Milan, Italy.
| | - Veronica Ferrari
- Dipartimento Di Scienze Farmacologiche E Biomolecolari, Università Degli Studi Di Milano, 20133, Milan, Italy.
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11
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Mee Hayes E, Sirvio L, Ye Y. A Potential Mechanism for Targeting Aggregates With Proteasomes and Disaggregases in Liquid Droplets. Front Aging Neurosci 2022; 14:854380. [PMID: 35517053 PMCID: PMC9062979 DOI: 10.3389/fnagi.2022.854380] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 02/18/2022] [Indexed: 01/26/2023] Open
Abstract
Insoluble protein deposits are hallmarks of neurodegenerative disorders and common forms of dementia. The aberrant aggregation of misfolded proteins involves a complex cascade of events that occur over time, from the cellular to the clinical phase of neurodegeneration. Declining neuronal health through increased cell stress and loss of protein homeostasis (proteostasis) functions correlate with the accumulation of aggregates. On the cellular level, increasing evidence supports that misfolded proteins may undergo liquid-liquid phase separation (LLPS), which is emerging as an important process to drive protein aggregation. Studying, the reverse process of aggregate disassembly and degradation has only recently gained momentum, following reports of enzymes with distinct aggregate-disassembly activities. In this review, we will discuss how the ubiquitin-proteasome system and disaggregation machineries such as VCP/p97 and HSP70 system may disassemble and/or degrade protein aggregates. In addition to their canonically associated functions, these enzymes appear to share a common feature: reversibly assembling into liquid droplets in an LLPS-driven manner. We review the role of LLPS in enhancing the disassembly of aggregates through locally increasing the concentration of these enzymes and their co-proteins together within droplet structures. We propose that such activity may be achieved through the concerted actions of disaggregase machineries, the ubiquitin-proteasome system and their co-proteins, all of which are condensed within transient aggregate-associated droplets (TAADs), ultimately resulting in aggregate clearance. We further speculate that sustained engagement of these enzymatic activities within TAADs will be detrimental to normal cellular functions, where these activities are required. The possibility of facilitating endogenous disaggregation and degradation activities within TAADs potentially represents a novel target for therapeutic intervention to restore protein homeostasis at the early stages of neurodegeneration.
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Affiliation(s)
- Emma Mee Hayes
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, United Kingdom
- UK Dementia Research Institute at Imperial College London, London, United Kingdom
| | - Liina Sirvio
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, United Kingdom
- UK Dementia Research Institute at Imperial College London, London, United Kingdom
| | - Yu Ye
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, United Kingdom
- UK Dementia Research Institute at Imperial College London, London, United Kingdom
- *Correspondence: Yu Ye,
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12
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Mohan HM, Trzeciakiewicz H, Pithadia A, Crowley EV, Pacitto R, Safren N, Trotter B, Zhang C, Zhou X, Zhang Y, Basrur V, Paulson HL, Sharkey LM. RTL8 promotes nuclear localization of UBQLN2 to subnuclear compartments associated with protein quality control. Cell Mol Life Sci 2022; 79:176. [PMID: 35247097 PMCID: PMC9376861 DOI: 10.1007/s00018-022-04170-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 01/17/2022] [Accepted: 01/25/2022] [Indexed: 11/24/2022]
Abstract
The brain-expressed ubiquilins (UBQLNs) 1, 2 and 4 are a family of ubiquitin adaptor proteins that participate broadly in protein quality control (PQC) pathways, including the ubiquitin proteasome system (UPS). One family member, UBQLN2, has been implicated in numerous neurodegenerative diseases including ALS/FTD. UBQLN2 typically resides in the cytoplasm but in disease can translocate to the nucleus, as in Huntington's disease where it promotes the clearance of mutant Huntingtin. How UBQLN2 translocates to the nucleus and clears aberrant nuclear proteins, however, is not well understood. In a mass spectrometry screen to discover UBQLN2 interactors, we identified a family of small (13 kDa), highly homologous uncharacterized proteins, RTL8, and confirmed the interaction between UBQLN2 and RTL8 both in vitro using recombinant proteins and in vivo using mouse brain tissue. Under endogenous and overexpressed conditions, RTL8 localizes to nucleoli. When co-expressed with UBQLN2, RTL8 promotes nuclear translocation of UBQLN2. RTL8 also facilitates UBQLN2's nuclear translocation during heat shock. UBQLN2 and RTL8 colocalize within ubiquitin-enriched subnuclear structures containing PQC components. The robust effect of RTL8 on the nuclear translocation and subnuclear localization of UBQLN2 does not extend to the other brain-expressed ubiquilins, UBQLN1 and UBQLN4. Moreover, compared to UBQLN1 and UBQLN4, UBQLN2 preferentially stabilizes RTL8 levels in human cell lines and in mouse brain, supporting functional heterogeneity among UBQLNs. As a novel UBQLN2 interactor that recruits UBQLN2 to specific nuclear compartments, RTL8 may regulate UBQLN2 function in nuclear protein quality control.
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Affiliation(s)
- Harihar Milaganur Mohan
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA.,Graduate Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | | | - Amit Pithadia
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Emily V Crowley
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Regina Pacitto
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Nathaniel Safren
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA.,Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Bryce Trotter
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Chengxin Zhang
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Xiaogen Zhou
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Yang Zhang
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Venkatesha Basrur
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Henry L Paulson
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA. .,Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, 48109-2200, USA.
| | - Lisa M Sharkey
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA. .,Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, 48109-2200, USA.
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13
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Nel M, Mahungu AC, Monnakgotla N, Botha GR, Mulder NJ, Wu G, Rampersaud E, van Blitterswijk M, Wuu J, Cooley A, Myers J, Rademakers R, Taylor JP, Benatar M, Heckmann JM. Revealing the Mutational Spectrum in Southern Africans With Amyotrophic Lateral Sclerosis. Neurol Genet 2022; 8:e654. [PMID: 35047667 PMCID: PMC8756565 DOI: 10.1212/nxg.0000000000000654] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/08/2021] [Indexed: 11/15/2022]
Abstract
Background and Objectives To perform the first screen of 44 amyotrophic lateral sclerosis (ALS) genes in a cohort of African genetic ancestry individuals with ALS using whole-genome sequencing (WGS) data. Methods One hundred three consecutive cases with probable/definite ALS (using the revised El Escorial criteria), and self-categorized as African genetic ancestry, underwent WGS using various Illumina platforms. As population controls, 238 samples from various African WGS data sets were included. Our analysis was restricted to 44 ALS genes, which were curated for rare sequence variants and classified according to the American College of Medical Genetics guidelines as likely benign, uncertain significance, likely pathogenic, or pathogenic variants. Results Thirteen percent of 103 ALS cases harbored pathogenic variants; 5 different SOD1 variants (N87S, G94D, I114T, L145S, and L145F) in 5 individuals (5%, 1 familial case), pathogenic C9orf72 repeat expansions in 7 individuals (7%, 1 familial case) and a likely pathogenic ANXA11 (G38R) variant in 1 individual. Thirty individuals (29%) harbored ≥1 variant of uncertain significance; 10 of these variants had limited pathogenic evidence, although this was insufficient to permit confident classification as pathogenic. Discussion Our findings show that known ALS genes can be expected to identify a genetic cause of disease in >11% of sporadic ALS cases of African genetic ancestry. Similar to European cohorts, the 2 most frequent genes harboring pathogenic variants in this population group are C9orf72 and SOD1.
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Affiliation(s)
- Melissa Nel
- Neurology Research Group (M.N., A.C.M., N.M., J.M.H.), Neuroscience Institute, University of Cape Town; Computational Biology Division (M.N., A.C.M., N.M., G.R.B., N.J.M.), Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa; Center for Applied Bioinformatics (G.W., E.R., J.M.), St. Jude Children's Research Hospital, Memphis, TN; Department of Neuroscience (M.v.B.), Mayo Clinic, Jacksonville, FL; Department of Neurology (J.W., A.C., M.B.), University of Miami, FL; Center for Molecular Neurology (R.R.), University of Antwerp, Belguim; Department of Cell and Molecular Biology (J.P.T.), St. Jude Children's Research Hospital, Memphis, TN; and Neurology (J.M.H.), Department of Medicine, University of Cape Town, South Africa
| | - Amokelani C Mahungu
- Neurology Research Group (M.N., A.C.M., N.M., J.M.H.), Neuroscience Institute, University of Cape Town; Computational Biology Division (M.N., A.C.M., N.M., G.R.B., N.J.M.), Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa; Center for Applied Bioinformatics (G.W., E.R., J.M.), St. Jude Children's Research Hospital, Memphis, TN; Department of Neuroscience (M.v.B.), Mayo Clinic, Jacksonville, FL; Department of Neurology (J.W., A.C., M.B.), University of Miami, FL; Center for Molecular Neurology (R.R.), University of Antwerp, Belguim; Department of Cell and Molecular Biology (J.P.T.), St. Jude Children's Research Hospital, Memphis, TN; and Neurology (J.M.H.), Department of Medicine, University of Cape Town, South Africa
| | - Nomakhosazana Monnakgotla
- Neurology Research Group (M.N., A.C.M., N.M., J.M.H.), Neuroscience Institute, University of Cape Town; Computational Biology Division (M.N., A.C.M., N.M., G.R.B., N.J.M.), Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa; Center for Applied Bioinformatics (G.W., E.R., J.M.), St. Jude Children's Research Hospital, Memphis, TN; Department of Neuroscience (M.v.B.), Mayo Clinic, Jacksonville, FL; Department of Neurology (J.W., A.C., M.B.), University of Miami, FL; Center for Molecular Neurology (R.R.), University of Antwerp, Belguim; Department of Cell and Molecular Biology (J.P.T.), St. Jude Children's Research Hospital, Memphis, TN; and Neurology (J.M.H.), Department of Medicine, University of Cape Town, South Africa
| | - Gerrit R Botha
- Neurology Research Group (M.N., A.C.M., N.M., J.M.H.), Neuroscience Institute, University of Cape Town; Computational Biology Division (M.N., A.C.M., N.M., G.R.B., N.J.M.), Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa; Center for Applied Bioinformatics (G.W., E.R., J.M.), St. Jude Children's Research Hospital, Memphis, TN; Department of Neuroscience (M.v.B.), Mayo Clinic, Jacksonville, FL; Department of Neurology (J.W., A.C., M.B.), University of Miami, FL; Center for Molecular Neurology (R.R.), University of Antwerp, Belguim; Department of Cell and Molecular Biology (J.P.T.), St. Jude Children's Research Hospital, Memphis, TN; and Neurology (J.M.H.), Department of Medicine, University of Cape Town, South Africa
| | - Nicola J Mulder
- Neurology Research Group (M.N., A.C.M., N.M., J.M.H.), Neuroscience Institute, University of Cape Town; Computational Biology Division (M.N., A.C.M., N.M., G.R.B., N.J.M.), Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa; Center for Applied Bioinformatics (G.W., E.R., J.M.), St. Jude Children's Research Hospital, Memphis, TN; Department of Neuroscience (M.v.B.), Mayo Clinic, Jacksonville, FL; Department of Neurology (J.W., A.C., M.B.), University of Miami, FL; Center for Molecular Neurology (R.R.), University of Antwerp, Belguim; Department of Cell and Molecular Biology (J.P.T.), St. Jude Children's Research Hospital, Memphis, TN; and Neurology (J.M.H.), Department of Medicine, University of Cape Town, South Africa
| | - Gang Wu
- Neurology Research Group (M.N., A.C.M., N.M., J.M.H.), Neuroscience Institute, University of Cape Town; Computational Biology Division (M.N., A.C.M., N.M., G.R.B., N.J.M.), Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa; Center for Applied Bioinformatics (G.W., E.R., J.M.), St. Jude Children's Research Hospital, Memphis, TN; Department of Neuroscience (M.v.B.), Mayo Clinic, Jacksonville, FL; Department of Neurology (J.W., A.C., M.B.), University of Miami, FL; Center for Molecular Neurology (R.R.), University of Antwerp, Belguim; Department of Cell and Molecular Biology (J.P.T.), St. Jude Children's Research Hospital, Memphis, TN; and Neurology (J.M.H.), Department of Medicine, University of Cape Town, South Africa
| | - Evadnie Rampersaud
- Neurology Research Group (M.N., A.C.M., N.M., J.M.H.), Neuroscience Institute, University of Cape Town; Computational Biology Division (M.N., A.C.M., N.M., G.R.B., N.J.M.), Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa; Center for Applied Bioinformatics (G.W., E.R., J.M.), St. Jude Children's Research Hospital, Memphis, TN; Department of Neuroscience (M.v.B.), Mayo Clinic, Jacksonville, FL; Department of Neurology (J.W., A.C., M.B.), University of Miami, FL; Center for Molecular Neurology (R.R.), University of Antwerp, Belguim; Department of Cell and Molecular Biology (J.P.T.), St. Jude Children's Research Hospital, Memphis, TN; and Neurology (J.M.H.), Department of Medicine, University of Cape Town, South Africa
| | - Marka van Blitterswijk
- Neurology Research Group (M.N., A.C.M., N.M., J.M.H.), Neuroscience Institute, University of Cape Town; Computational Biology Division (M.N., A.C.M., N.M., G.R.B., N.J.M.), Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa; Center for Applied Bioinformatics (G.W., E.R., J.M.), St. Jude Children's Research Hospital, Memphis, TN; Department of Neuroscience (M.v.B.), Mayo Clinic, Jacksonville, FL; Department of Neurology (J.W., A.C., M.B.), University of Miami, FL; Center for Molecular Neurology (R.R.), University of Antwerp, Belguim; Department of Cell and Molecular Biology (J.P.T.), St. Jude Children's Research Hospital, Memphis, TN; and Neurology (J.M.H.), Department of Medicine, University of Cape Town, South Africa
| | - Joanne Wuu
- Neurology Research Group (M.N., A.C.M., N.M., J.M.H.), Neuroscience Institute, University of Cape Town; Computational Biology Division (M.N., A.C.M., N.M., G.R.B., N.J.M.), Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa; Center for Applied Bioinformatics (G.W., E.R., J.M.), St. Jude Children's Research Hospital, Memphis, TN; Department of Neuroscience (M.v.B.), Mayo Clinic, Jacksonville, FL; Department of Neurology (J.W., A.C., M.B.), University of Miami, FL; Center for Molecular Neurology (R.R.), University of Antwerp, Belguim; Department of Cell and Molecular Biology (J.P.T.), St. Jude Children's Research Hospital, Memphis, TN; and Neurology (J.M.H.), Department of Medicine, University of Cape Town, South Africa
| | - Anne Cooley
- Neurology Research Group (M.N., A.C.M., N.M., J.M.H.), Neuroscience Institute, University of Cape Town; Computational Biology Division (M.N., A.C.M., N.M., G.R.B., N.J.M.), Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa; Center for Applied Bioinformatics (G.W., E.R., J.M.), St. Jude Children's Research Hospital, Memphis, TN; Department of Neuroscience (M.v.B.), Mayo Clinic, Jacksonville, FL; Department of Neurology (J.W., A.C., M.B.), University of Miami, FL; Center for Molecular Neurology (R.R.), University of Antwerp, Belguim; Department of Cell and Molecular Biology (J.P.T.), St. Jude Children's Research Hospital, Memphis, TN; and Neurology (J.M.H.), Department of Medicine, University of Cape Town, South Africa
| | - Jason Myers
- Neurology Research Group (M.N., A.C.M., N.M., J.M.H.), Neuroscience Institute, University of Cape Town; Computational Biology Division (M.N., A.C.M., N.M., G.R.B., N.J.M.), Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa; Center for Applied Bioinformatics (G.W., E.R., J.M.), St. Jude Children's Research Hospital, Memphis, TN; Department of Neuroscience (M.v.B.), Mayo Clinic, Jacksonville, FL; Department of Neurology (J.W., A.C., M.B.), University of Miami, FL; Center for Molecular Neurology (R.R.), University of Antwerp, Belguim; Department of Cell and Molecular Biology (J.P.T.), St. Jude Children's Research Hospital, Memphis, TN; and Neurology (J.M.H.), Department of Medicine, University of Cape Town, South Africa
| | - Rosa Rademakers
- Neurology Research Group (M.N., A.C.M., N.M., J.M.H.), Neuroscience Institute, University of Cape Town; Computational Biology Division (M.N., A.C.M., N.M., G.R.B., N.J.M.), Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa; Center for Applied Bioinformatics (G.W., E.R., J.M.), St. Jude Children's Research Hospital, Memphis, TN; Department of Neuroscience (M.v.B.), Mayo Clinic, Jacksonville, FL; Department of Neurology (J.W., A.C., M.B.), University of Miami, FL; Center for Molecular Neurology (R.R.), University of Antwerp, Belguim; Department of Cell and Molecular Biology (J.P.T.), St. Jude Children's Research Hospital, Memphis, TN; and Neurology (J.M.H.), Department of Medicine, University of Cape Town, South Africa
| | - J Paul Taylor
- Neurology Research Group (M.N., A.C.M., N.M., J.M.H.), Neuroscience Institute, University of Cape Town; Computational Biology Division (M.N., A.C.M., N.M., G.R.B., N.J.M.), Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa; Center for Applied Bioinformatics (G.W., E.R., J.M.), St. Jude Children's Research Hospital, Memphis, TN; Department of Neuroscience (M.v.B.), Mayo Clinic, Jacksonville, FL; Department of Neurology (J.W., A.C., M.B.), University of Miami, FL; Center for Molecular Neurology (R.R.), University of Antwerp, Belguim; Department of Cell and Molecular Biology (J.P.T.), St. Jude Children's Research Hospital, Memphis, TN; and Neurology (J.M.H.), Department of Medicine, University of Cape Town, South Africa
| | - Michael Benatar
- Neurology Research Group (M.N., A.C.M., N.M., J.M.H.), Neuroscience Institute, University of Cape Town; Computational Biology Division (M.N., A.C.M., N.M., G.R.B., N.J.M.), Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa; Center for Applied Bioinformatics (G.W., E.R., J.M.), St. Jude Children's Research Hospital, Memphis, TN; Department of Neuroscience (M.v.B.), Mayo Clinic, Jacksonville, FL; Department of Neurology (J.W., A.C., M.B.), University of Miami, FL; Center for Molecular Neurology (R.R.), University of Antwerp, Belguim; Department of Cell and Molecular Biology (J.P.T.), St. Jude Children's Research Hospital, Memphis, TN; and Neurology (J.M.H.), Department of Medicine, University of Cape Town, South Africa
| | - Jeannine M Heckmann
- Neurology Research Group (M.N., A.C.M., N.M., J.M.H.), Neuroscience Institute, University of Cape Town; Computational Biology Division (M.N., A.C.M., N.M., G.R.B., N.J.M.), Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa; Center for Applied Bioinformatics (G.W., E.R., J.M.), St. Jude Children's Research Hospital, Memphis, TN; Department of Neuroscience (M.v.B.), Mayo Clinic, Jacksonville, FL; Department of Neurology (J.W., A.C., M.B.), University of Miami, FL; Center for Molecular Neurology (R.R.), University of Antwerp, Belguim; Department of Cell and Molecular Biology (J.P.T.), St. Jude Children's Research Hospital, Memphis, TN; and Neurology (J.M.H.), Department of Medicine, University of Cape Town, South Africa
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14
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Higgins NR, Greenslade JE, Wu JJ, Miranda E, Galliciotti G, Monteiro MJ. Serpin neuropathology in the P497S UBQLN2 mouse model of ALS/FTD. Brain Pathol 2021; 31:e12948. [PMID: 33780087 PMCID: PMC8387369 DOI: 10.1111/bpa.12948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 02/17/2021] [Accepted: 03/08/2021] [Indexed: 01/12/2023] Open
Abstract
Accumulating evidence suggests X-linked dominant mutations in UBQLN2 cause amyotrophic lateral sclerosis (ALS) with frontotemporal dementia (FTD) through both loss- and gain-of-function mechanisms. However, the mechanisms by which the mutations cause disease are still unclear. The goal of the study was to uncover the possible pathomechanism(s) by which UBQLN2 mutations cause ALS/FTD. An analysis of proteomic changes in neuronal tissue was used to identify proteins with altered accumulation in the P497S UBQLN2 transgenic mouse model of ALS/FTD. We then used immunocytochemistry and biochemical techniques to confirm protein changes in the mutant P497S mice. Additionally, we used cell lines inactivated of UBQLN2 expression to determine whether its loss underlies the alteration in the proteins seen in P497S mice. The proteome screen identified a dramatic alteration of serine protease inhibitor (serpin) proteins in the mutant P497S animals. Double immunofluorescent staining of brain and spinal cord tissues of the mutant and control mice revealed an age-dependent change in accumulation of Serpin A1, C1, and I1 in puncta whose staining colocalized with UBQLN2 puncta in the mutant P497S mice. Serpin A1 aggregation in P497S animals was confirmed by biochemical extraction and filter retardation assays. A similar phenomenon of serpin protein aggregation was found in HeLa and NSC34 motor neuron cells with inactivated UBQLN2 expression. We found aberrant aggregation of serpin proteins, particularly Serpin A1, in the brain and spinal cord of the P497S UBQLN2 mouse model of ALS/FTD. Similar aggregation of serpin proteins was found in UBQLN2 knockout cells suggesting that serpin aggregation in the mutant P497S animals may stem from loss of UBQLN2 function. Because serpin aggregation is known to cause disease through both loss- and gain-of-function mechanisms, we speculate that their accumulation in the P497S mouse model of ALS/FTD may contribute to disease pathogenesis through similar mechanism(s).
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Affiliation(s)
- Nicole R. Higgins
- Program in Molecular MedicineUniversity of Maryland School of MedicineBaltimoreMDUSA
- Center for Biomedical Engineering and TechnologyDepartment of Anatomy and NeurobiologyUniversity of Maryland School of MedicineBaltimoreMDUSA
| | - Jessie E. Greenslade
- Center for Biomedical Engineering and TechnologyDepartment of Anatomy and NeurobiologyUniversity of Maryland School of MedicineBaltimoreMDUSA
| | - Josephine J. Wu
- Center for Biomedical Engineering and TechnologyDepartment of Anatomy and NeurobiologyUniversity of Maryland School of MedicineBaltimoreMDUSA
| | - Elena Miranda
- Department of Biology and Biotechnologies ‘Charles Darwin’Pasteur Institute – Cenci Bolognetti FoundationSapienza University of RomeRomeItaly
| | - Giovanna Galliciotti
- Institute of NeuropathologyUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | - Mervyn J. Monteiro
- Program in Molecular MedicineUniversity of Maryland School of MedicineBaltimoreMDUSA
- Center for Biomedical Engineering and TechnologyDepartment of Anatomy and NeurobiologyUniversity of Maryland School of MedicineBaltimoreMDUSA
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15
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Gerson JE, Safren N, Fischer S, Patel R, Crowley EV, Welday JP, Windle AK, Barmada S, Paulson HL, Sharkey LM. Ubiquilin-2 differentially regulates polyglutamine disease proteins. Hum Mol Genet 2021; 29:2596-2610. [PMID: 32681165 DOI: 10.1093/hmg/ddaa152] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 07/07/2020] [Accepted: 07/13/2020] [Indexed: 12/12/2022] Open
Abstract
Divergent protein context helps explain why polyglutamine expansion diseases differ clinically and pathologically. This heterogeneity may also extend to how polyglutamine disease proteins are handled by cellular pathways of proteostasis. Studies suggest, for example, that the ubiquitin-proteasome shuttle protein Ubiquilin-2 (UBQLN2) selectively interacts with specific polyglutamine disease proteins. Here we employ cellular models, primary neurons and mouse models to investigate the potential differential regulation by UBQLN2 of two polyglutamine disease proteins, huntingtin (HTT) and ataxin-3 (ATXN3). In cells, overexpressed UBQLN2 selectively lowered levels of full-length pathogenic HTT but not of HTT exon 1 fragment or full-length ATXN3. Consistent with these results, UBQLN2 specifically reduced accumulation of aggregated mutant HTT but not mutant ATXN3 in mouse models of Huntington's disease (HD) and spinocerebellar ataxia type 3 (SCA3), respectively. Normally a cytoplasmic protein, UBQLN2 translocated to the nuclei of neurons in HD mice but not in SCA3 mice. Remarkably, instead of reducing the accumulation of nuclear mutant ATXN3, UBQLN2 induced an accumulation of cytoplasmic ATXN3 aggregates in neurons of SCA3 mice. Together these results reveal a selective action of UBQLN2 toward polyglutamine disease proteins, indicating that polyglutamine expansion alone is insufficient to promote UBQLN2-mediated clearance of this class of disease proteins. Additional factors, including nuclear translocation of UBQLN2, may facilitate its action to clear intranuclear, aggregated disease proteins like HTT.
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Affiliation(s)
- Julia E Gerson
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Nathaniel Safren
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Svetlana Fischer
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Ronak Patel
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Emily V Crowley
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Jacqueline P Welday
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Alexandra K Windle
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Sami Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Henry L Paulson
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Lisa M Sharkey
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
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16
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Rana T, Behl T, Sehgal A, Mehta V, Singh S, Bhatia S, Al-Harrasi A, Bungau S. Exploring the Role of Autophagy Dysfunction in Neurodegenerative Disorders. Mol Neurobiol 2021; 58:4886-4905. [PMID: 34212304 DOI: 10.1007/s12035-021-02472-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 06/21/2021] [Indexed: 12/12/2022]
Abstract
Autophagy is a catabolic pathway by which misfolded proteins or damaged organelles are engulfed by autophagosomes and then transported to lysosomes for degradation. Recently, a great improvement has been done to explain the molecular mechanisms and roles of autophagy in several important cellular metabolic processes. Besides being a vital clearance pathway or a cell survival pathway in response to different stresses, autophagy dysfunction, either upregulated or down-regulated, has been suggested to be linked with numerous neurodegenerative disorders like Alzheimer's disease, Parkinson's disease, Huntington's disease, and Amyotrophic lateral sclerosis. Impairment at different stages of autophagy results in the formation of large protein aggregates and damaged organelles, which leads to the onset and progression of different neurodegenerative disorders. This article elucidates the recent progress about the role of autophagy in neurodegenerative disorders and explains how autophagy dysfunction is linked with the pathogenesis of such disorders as well as the novel potential autophagy-associated therapies for treating them.
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Affiliation(s)
- Tarapati Rana
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
- Government Pharmacy College, Seraj, Mandi, Himachal Pradesh, India
| | - Tapan Behl
- Chitkara College of Pharmacy, Chitkara University, Punjab, India.
| | - Aayush Sehgal
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Vineet Mehta
- Government College of Pharmacy, Rohru, Distt. Shimla, Himachal Pradesh, India
| | - Sukhbir Singh
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Saurabh Bhatia
- Amity Institute of Pharmacy, Amity University, Haryana, India
- Natural & Medical Sciences Research Centre, University of Nizwa, Nizwa, Oman
| | - Ahmed Al-Harrasi
- Natural & Medical Sciences Research Centre, University of Nizwa, Nizwa, Oman
| | - Simona Bungau
- Department of Pharmacy, Faculty of Medicine and Pharmacy, University of Oradea, Oradea, Romania
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17
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Lin BC, Phung TH, Higgins NR, Greenslade JE, Prado MA, Finley D, Karbowski M, Polster BM, Monteiro MJ. ALS/FTD mutations in UBQLN2 are linked to mitochondrial dysfunction through loss-of-function in mitochondrial protein import. Hum Mol Genet 2021; 30:1230-1246. [PMID: 33891006 PMCID: PMC8212775 DOI: 10.1093/hmg/ddab116] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/13/2021] [Accepted: 04/16/2021] [Indexed: 01/12/2023] Open
Abstract
UBQLN2 mutations cause amyotrophic lateral sclerosis (ALS) with frontotemporal dementia (FTD), but the pathogenic mechanisms by which they cause disease remain unclear. Proteomic profiling identified 'mitochondrial proteins' as comprising the largest category of protein changes in the spinal cord (SC) of the P497S UBQLN2 mouse model of ALS/FTD. Immunoblots confirmed P497S animals have global changes in proteins predictive of a severe decline in mitochondrial health, including oxidative phosphorylation (OXPHOS), mitochondrial protein import and network dynamics. Functional studies confirmed mitochondria purified from the SC of P497S animals have age-dependent decline in nearly all steps of OXPHOS. Mitochondria cristae deformities were evident in spinal motor neurons of aged P497S animals. Knockout (KO) of UBQLN2 in HeLa cells resulted in changes in mitochondrial proteins and OXPHOS activity similar to those seen in the SC. KO of UBQLN2 also compromised targeting and processing of the mitochondrial import factor, TIMM44, resulting in accumulation in abnormal foci. The functional OXPHOS deficits and TIMM44-targeting defects were rescued by reexpression of WT UBQLN2 but not by ALS/FTD mutant UBQLN2 proteins. In vitro binding assays revealed ALS/FTD mutant UBQLN2 proteins bind weaker with TIMM44 than WT UBQLN2 protein, suggesting that the loss of UBQLN2 binding may underlie the import and/or delivery defect of TIMM44 to mitochondria. Our studies indicate a potential key pathogenic disturbance in mitochondrial health caused by UBQLN2 mutations.
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Affiliation(s)
- Brian C Lin
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Trong H Phung
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Nicole R Higgins
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jessie E Greenslade
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Miguel A Prado
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Daniel Finley
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Mariusz Karbowski
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Brian M Polster
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anesthesiology, Center for Shock, Trauma and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Mervyn J Monteiro
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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18
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Riley JF, Fioramonti PJ, Rusnock AK, Hehnly H, Castañeda CA. ALS-linked mutations impair UBQLN2 stress-induced biomolecular condensate assembly in cells. J Neurochem 2021; 159:145-155. [PMID: 34129687 DOI: 10.1111/jnc.15453] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 05/30/2021] [Accepted: 06/13/2021] [Indexed: 11/28/2022]
Abstract
Mutations in Ubiquilin-2 (UBQLN2), a ubiquitin-binding shuttle protein involved in several protein quality control processes, can lead to amyotrophic lateral sclerosis (ALS). We previously found that wild-type UBQLN2 forms dynamic, membraneless biomolecular condensates upon cellular stress, and undergoes liquid-liquid phase separation in vitro. However, the impact of ALS-linked mutations on UBQLN2 condensate formation in cells is unknown. Here, we employ live-cell imaging and photokinetic analysis to investigate how five patient-derived ALS-linked mutations in UBQLN2 impact stress-induced UBQLN2 condensate assembly and condensate material properties. Both wild-type and mutant UBQLN2 condensates are generally cytoplasmic and liquid-like. However, cells transfected with mutant UBQLN2 contain fewer stress-induced UBQLN2 condensates than those with wild-type UBQLN2. Most strikingly, exogenously expressed P506T UBQLN2 forms the lowest number of stress-induced condensates of all UBQLN2 mutants, and these condensates are significantly smaller than those of wild-type UBQLN2. Fluorescence recovery after photobleaching (FRAP) analysis of UBQLN2 condensates revealed higher immobile fractions for UBQLN2 mutants, especially P506T. P497S and P497H mutations differentially impact condensate properties, demonstrating that the effects of ALS-linked mutations are both position- and amino acid-dependent. Collectively, our data show that disease mutations hinder assembly and alter viscoelastic properties of stress-induced UBQLN2 condensates, potentially leading to aggregates commonly observed in ALS.
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Affiliation(s)
- Julia F Riley
- Department of Biology, Syracuse University, Syracuse, NY, 13244, USA.,Department of Chemistry, Syracuse University, Syracuse, NY, 13244, USA.,Interdisciplinary Neuroscience Program, Syracuse University, Syracuse, NY, 13244, USA
| | | | - Amber K Rusnock
- Department of Biology, Syracuse University, Syracuse, NY, 13244, USA
| | - Heidi Hehnly
- Department of Biology, Syracuse University, Syracuse, NY, 13244, USA
| | - Carlos A Castañeda
- Department of Biology, Syracuse University, Syracuse, NY, 13244, USA.,Department of Chemistry, Syracuse University, Syracuse, NY, 13244, USA.,Interdisciplinary Neuroscience Program, Syracuse University, Syracuse, NY, 13244, USA
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19
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Saxton AD, Kraemer BC. Human Ubiquilin 2 and TDP-43 co-pathology drives neurodegeneration in transgenic C. elegans. G3-GENES GENOMES GENETICS 2021; 11:6272515. [PMID: 33963840 DOI: 10.1093/g3journal/jkab158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/01/2021] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a debilitating, fatal neurodegenerative disease that causes rapid muscle wasting. It shares a spectrum of symptoms and pathology with frontotemporal lobar degeneration (FTLD). These diseases are caused by aberrant activity of a set of proteins including TDP-43 and UBIQUILIN-2 (UBQLN2). UBQLN2 encodes an ubiquitin-like adaptor protein involved in the ubiquitin-proteasome protein degradation pathway. Mutations in the PXX domain of UBQLN2 cause familial ALS. UBQLN2 aggregates in skein-like inclusions with other ALS and FTLD associated proteins including TDP-43 and ubiquitin. To facilitate further investigation of UBQLN2-mediated mechanisms of neurodegeneration, we made Caenorhabditis elegans transgenic lines pan-neuronally expressing human UBQLN2 cDNAs carrying either the wild-type UBQLN2 sequence or UBQLN2 with ALS causing mutations. Transgenic animals exhibit motor dysfunction accompanied by neurodegeneration of GABAergic motor neurons. At low levels of UBQLN2 expression, wild-type UBQLN2 causes significant motor impairment and neurodegeneration that is exacerbated by ALS associated mutations in UBQLN2. At higher levels of UBQLN2 expression, both wild-type and ALS mutated versions of UBQLN2 cause severe impairment. Molecular genetic investigation revealed that UBQLN2 dependent locomotor defects do not require the involvement of the endogenous homolog of TDP-43 in C. elegans (tdp-1). However, co-expression of wild-type human TDP-43 exacerbates UBQLN2 deficits. This model of UBQLN2-mediated neurodegeneration may be useful for further mechanistic investigation into the molecular cascades driving neurodegeneration in ALS and ALS-FTLD.
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Affiliation(s)
- Aleen D Saxton
- Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington, 98108, United States of America
| | - Brian C Kraemer
- Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington, 98108, United States of America; Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98104, USA; Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, Washington 98195, USA; Department of Pathology, University of Washington School of Medicine, Seattle, Washington 98195, USA
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20
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Impaired 26S Proteasome Assembly Precedes Neuronal Loss in Mutant UBQLN2 Rats. Int J Mol Sci 2021; 22:ijms22094319. [PMID: 33919255 PMCID: PMC8122323 DOI: 10.3390/ijms22094319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/15/2021] [Accepted: 04/19/2021] [Indexed: 11/17/2022] Open
Abstract
Proteasomal dysfunction is known to be associated with amyotrophic lateral sclerosis and frontotemporal degeneration (ALS/FTD). Our previous reports have shown that a mutant form of ubiquilin-2 (UBQLN2) linked to ALS/FTD leads to neurodegeneration accompanied by accumulations of the proteasome subunit Rpt1 in transgenic rats, but the precise pathogenic mechanisms of how this mutation impairs the proteasome remains to be elucidated. Here, we reveal that this UBQLN2 mutation in rats disrupted the proteasome integrity prior to neurodegeneration, that it dissociated the 26S proteasome in vitro, and that its depletion did not affect 26S proteasome assembly. During both disease progression and in an age-dependent manner, we found that proteasome subunits were translocated to the nucleus, including both of the 20S core particles (PSMA1 and PSMB7) and the 19S regulatory particles (Rpt1 and Rpn1), suggesting that defective proteasome function may result from the proteasome-subunit mislocalization. Taken together, the present data demonstrate that impaired proteasome assembly is an early event in the pathogenesis of UBQLN2-associated neurodegeneration in mutant UBQLN2 rats.
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21
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It's not just a phase; ubiquitination in cytosolic protein quality control. Biochem Soc Trans 2021; 49:365-377. [PMID: 33634825 PMCID: PMC7924994 DOI: 10.1042/bst20200694] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 02/04/2023]
Abstract
The accumulation of misfolded proteins is associated with numerous degenerative conditions, cancers and genetic diseases. These pathological imbalances in protein homeostasis (termed proteostasis), result from the improper triage and disposal of damaged and defective proteins from the cell. The ubiquitin-proteasome system is a key pathway for the molecular control of misfolded cytosolic proteins, co-opting a cascade of ubiquitin ligases to direct terminally damaged proteins to the proteasome via modification with chains of the small protein, ubiquitin. Despite the evidence for ubiquitination in this critical pathway, the precise complement of ubiquitin ligases and deubiquitinases that modulate this process remains under investigation. Whilst chaperones act as the first line of defence against protein misfolding, the ubiquitination machinery has a pivotal role in targeting terminally defunct cytosolic proteins for destruction. Recent work points to a complex assemblage of chaperones, ubiquitination machinery and subcellular quarantine as components of the cellular arsenal against proteinopathies. In this review, we examine the contribution of these pathways and cellular compartments to the maintenance of the cytosolic proteome. Here we will particularly focus on the ubiquitin code and the critical enzymes which regulate misfolded proteins in the cytosol, the molecular point of origin for many neurodegenerative and genetic diseases.
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22
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Whiteley AM, Prado MA, de Poot SAH, Paulo JA, Ashton M, Dominguez S, Weber M, Ngu H, Szpyt J, Jedrychowski MP, Easton A, Gygi SP, Kurz T, Monteiro MJ, Brown EJ, Finley D. Global proteomics of Ubqln2-based murine models of ALS. J Biol Chem 2020; 296:100153. [PMID: 33277362 PMCID: PMC7873701 DOI: 10.1074/jbc.ra120.015960] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 11/21/2020] [Accepted: 12/04/2020] [Indexed: 12/12/2022] Open
Abstract
Familial neurodegenerative diseases commonly involve mutations that result in either aberrant proteins or dysfunctional components of the proteolytic machinery that act on aberrant proteins. UBQLN2 is a ubiquitin receptor of the UBL/UBA family that binds the proteasome through its ubiquitin-like domain and is thought to deliver ubiquitinated proteins to proteasomes for degradation. UBQLN2 mutations result in familial amyotrophic lateral sclerosis (ALS)/frontotemporal dementia in humans through an unknown mechanism. Quantitative multiplexed proteomics was used to provide for the first time an unbiased and global analysis of the role of Ubqln2 in controlling the composition of the proteome. We studied several murine models of Ubqln2-linked ALS and also generated Ubqln2 null mutant mice. We identified impacts of Ubqln2 on diverse physiological pathways, most notably serotonergic signaling. Interestingly, we observed an upregulation of proteasome subunits, suggesting a compensatory response to diminished proteasome output. Among the specific proteins whose abundance is linked to UBQLN2 function, the strongest hits were the ubiquitin ligase TRIM32 and two retroelement-derived proteins, PEG10 and CXX1B. Cycloheximide chase studies using induced human neurons and HEK293 cells suggested that PEG10 and TRIM32 are direct clients. Although UBQLN2 directs the degradation of multiple proteins via the proteasome, it surprisingly conferred strong protection from degradation on the Gag-like protein CXX1B, which is expressed from the same family of retroelement genes as PEG10. In summary, this study charts the proteomic landscape of ALS-related Ubqln2 mutants and identifies candidate client proteins that are altered in vivo in disease models and whose degradation is promoted by UBQLN2.
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Affiliation(s)
| | - Miguel A Prado
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | | | - Joao A Paulo
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Marissa Ashton
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Sara Dominguez
- Department of Neuroscience, Genentech Inc, South San Francisco, California, USA
| | - Martin Weber
- Department of Neuroscience, Genentech Inc, South San Francisco, California, USA
| | - Hai Ngu
- Department of Pathology, Genentech Inc, South San Francisco, California, USA
| | - John Szpyt
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Mark P Jedrychowski
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Amy Easton
- Department of Neuroscience, Genentech Inc, South San Francisco, California, USA
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Thimo Kurz
- Henry Wellcome Lab of Cell Biology, College of Medical, Veterinary and Life Sciences, Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, United Kingdom
| | - Mervyn J Monteiro
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland Medical School, Baltimore, Maryland, USA
| | - Eric J Brown
- Department of Immunology and Infectious Diseases, Genentech Inc, South San Francisco, California, USA
| | - Daniel Finley
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA.
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23
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McAlary L, Chew YL, Lum JS, Geraghty NJ, Yerbury JJ, Cashman NR. Amyotrophic Lateral Sclerosis: Proteins, Proteostasis, Prions, and Promises. Front Cell Neurosci 2020; 14:581907. [PMID: 33328890 PMCID: PMC7671971 DOI: 10.3389/fncel.2020.581907] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is characterized by the progressive degeneration of the motor neurons that innervate muscle, resulting in gradual paralysis and culminating in the inability to breathe or swallow. This neuronal degeneration occurs in a spatiotemporal manner from a point of onset in the central nervous system (CNS), suggesting that there is a molecule that spreads from cell-to-cell. There is strong evidence that the onset and progression of ALS pathology is a consequence of protein misfolding and aggregation. In line with this, a hallmark pathology of ALS is protein deposition and inclusion formation within motor neurons and surrounding glia of the proteins TAR DNA-binding protein 43, superoxide dismutase-1, or fused in sarcoma. Collectively, the observed protein aggregation, in conjunction with the spatiotemporal spread of symptoms, strongly suggests a prion-like propagation of protein aggregation occurs in ALS. In this review, we discuss the role of protein aggregation in ALS concerning protein homeostasis (proteostasis) mechanisms and prion-like propagation. Furthermore, we examine the experimental models used to investigate these processes, including in vitro assays, cultured cells, invertebrate models, and murine models. Finally, we evaluate the therapeutics that may best prevent the onset or spread of pathology in ALS and discuss what lies on the horizon for treating this currently incurable disease.
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Affiliation(s)
- Luke McAlary
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Yee Lian Chew
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Jeremy Stephen Lum
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Nicholas John Geraghty
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Justin John Yerbury
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Neil R. Cashman
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
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24
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Halloran M, Ragagnin AMG, Vidal M, Parakh S, Yang S, Heng B, Grima N, Shahheydari H, Soo KY, Blair I, Guillemin GJ, Sundaramoorthy V, Atkin JD. Amyotrophic lateral sclerosis-linked UBQLN2 mutants inhibit endoplasmic reticulum to Golgi transport, leading to Golgi fragmentation and ER stress. Cell Mol Life Sci 2020; 77:3859-3873. [PMID: 31802140 PMCID: PMC11105036 DOI: 10.1007/s00018-019-03394-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 10/28/2019] [Accepted: 11/22/2019] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are fatal neurodegenerative diseases that are related genetically and pathologically. Mutations in the UBQLN2 gene, encoding the ubiquitin-like protein ubiquilin2, are associated with familial ALS/FTD, but the pathophysiological mechanisms remain unclear. Here, we demonstrate that ALS/FTD UBQLN2 mutants P497H and P506T inhibit protein transport from the endoplasmic reticulum (ER) to the Golgi apparatus in neuronal cells. In addition, we observed that Sec31-positive ER exit sites are clustered in UBQLN2T487I patient spinal cord tissues. Both the ER-Golgi intermediate (ERGIC) compartment and the Golgi become disorganised and fragmented. This activates ER stress and inhibits ER-associated degradation. Hence, this study highlights perturbations in secretory protein trafficking and ER homeostasis as pathogenic mechanisms associated with ALS/FTD-associated forms of UBQLN2.
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Affiliation(s)
- Mark Halloran
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Audrey M G Ragagnin
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Marta Vidal
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Sonam Parakh
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Shu Yang
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Benjamin Heng
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Natalie Grima
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Hamideh Shahheydari
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Kai-Ying Soo
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Ian Blair
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Gilles J Guillemin
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Vinod Sundaramoorthy
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Julie D Atkin
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia.
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Melbourne, Australia.
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25
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Zheng T, Yang Y, Castañeda CA. Structure, dynamics and functions of UBQLNs: at the crossroads of protein quality control machinery. Biochem J 2020; 477:3471-3497. [PMID: 32965492 PMCID: PMC7737201 DOI: 10.1042/bcj20190497] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/23/2020] [Accepted: 08/26/2020] [Indexed: 12/12/2022]
Abstract
Cells rely on protein homeostasis to maintain proper biological functions. Dysregulation of protein homeostasis contributes to the pathogenesis of many neurodegenerative diseases and cancers. Ubiquilins (UBQLNs) are versatile proteins that engage with many components of protein quality control (PQC) machinery in cells. Disease-linked mutations of UBQLNs are most commonly associated with amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and other neurodegenerative disorders. UBQLNs play well-established roles in PQC processes, including facilitating degradation of substrates through the ubiquitin-proteasome system (UPS), autophagy, and endoplasmic-reticulum-associated protein degradation (ERAD) pathways. In addition, UBQLNs engage with chaperones to sequester, degrade, or assist repair of misfolded client proteins. Furthermore, UBQLNs regulate DNA damage repair mechanisms, interact with RNA-binding proteins (RBPs), and engage with cytoskeletal elements to regulate cell differentiation and development. Important to the myriad functions of UBQLNs are its multidomain architecture and ability to self-associate. UBQLNs are linked to numerous types of cellular puncta, including stress-induced biomolecular condensates, autophagosomes, aggresomes, and aggregates. In this review, we focus on deciphering how UBQLNs function on a molecular level. We examine the properties of oligomerization-driven interactions among the structured and intrinsically disordered segments of UBQLNs. These interactions, together with the knowledge from studies of disease-linked mutations, provide significant insights to UBQLN structure, dynamics and function.
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Affiliation(s)
- Tongyin Zheng
- Department of Chemistry, Syracuse University, Syracuse, NY 13244, U.S.A
| | - Yiran Yang
- Department of Chemistry, Syracuse University, Syracuse, NY 13244, U.S.A
| | - Carlos A. Castañeda
- Department of Chemistry, Syracuse University, Syracuse, NY 13244, U.S.A
- Departments of Biology and Chemistry, Syracuse University, Syracuse, NY 13244, U.S.A
- Bioinspired Institute, and the Interdisciplinary Neuroscience Program, Syracuse University, Syracuse, NY 13244, U.S.A
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26
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Proteasome Subunits Involved in Neurodegenerative Diseases. Arch Med Res 2020; 52:1-14. [PMID: 32962866 DOI: 10.1016/j.arcmed.2020.09.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 07/25/2020] [Accepted: 09/04/2020] [Indexed: 12/29/2022]
Abstract
The ubiquitin-proteasome system is the major pathway for the maintenance of protein homeostasis. Its inhibition causes accumulation of ubiquitinated proteins; this accumulation has been associated with several of the most common neurodegenerative diseases. Several genetic factors have been identified for most neurodegenerative diseases, however, most cases are considered idiopathic, thus making the study of the mechanisms of protein accumulation a relevant field of research. It is often mentioned that the biggest risk factor for neurodegenerative diseases is aging, and several groups have reported an age-related alteration of the expression of some of the 26S proteasome subunits and a reduction of its activity. Proteasome subunits interact with proteins that are known to accumulate in neurodegenerative diseases such as α-synuclein in Parkinson's, tau in Alzheimer's, and huntingtin in Huntington's diseases. These interactions have been explored for several years, but only until recently, we are beginning to understand them. In this review, we discuss the known interactions, the underlying patterns, and the phenotypes associated with the 26S proteasome subunits in the etiology and progression of neurodegenerative diseases where there is evidence of proteasome involvement. Special emphasis is made in reviewing proteasome subunits that interact with proteins known to have an age-related altered expression or to be involved in neurodegenerative diseases to explore key effectors that may trigger or augment their progression. Interestingly, while the causes of age-related reduction of some of the proteasome subunits are not known, there are specific relationships between the observed neurodegenerative disease and the affected proteasome subunits.
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Ranganathan R, Haque S, Coley K, Shepheard S, Cooper-Knock J, Kirby J. Multifaceted Genes in Amyotrophic Lateral Sclerosis-Frontotemporal Dementia. Front Neurosci 2020; 14:684. [PMID: 32733193 PMCID: PMC7358438 DOI: 10.3389/fnins.2020.00684] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 06/04/2020] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis and frontotemporal dementia are two progressive, adult onset neurodegenerative diseases, caused by the cell death of motor neurons in the motor cortex and spinal cord and cortical neurons in the frontal and temporal lobes, respectively. Whilst these have previously appeared to be quite distinct disorders, in terms of areas affected and clinical symptoms, identification of cognitive dysfunction as a component of amyotrophic lateral sclerosis (ALS), with some patients presenting with both ALS and FTD, overlapping features of neuropathology and the ongoing discoveries that a significant proportion of the genes underlying the familial forms of the disease are the same, has led to ALS and FTD being described as a disease spectrum. Many of these genes encode proteins in common biological pathways including RNA processing, autophagy, ubiquitin proteasome system, unfolded protein response and intracellular trafficking. This article provides an overview of the ALS-FTD genes before summarizing other known ALS and FTD causing genes where mutations have been found primarily in patients of one disease and rarely in the other. In discussing these genes, the review highlights the similarity of biological pathways in which the encoded proteins function and the interactions that occur between these proteins, whilst recognizing the distinctions of MAPT-related FTD and SOD1-related ALS. However, mutations in all of these genes result in similar pathology including protein aggregation and neuroinflammation, highlighting that multiple different mechanisms lead to common downstream effects and neuronal loss. Next generation sequencing has had a significant impact on the identification of genes associated with both diseases, and has also highlighted the widening clinical phenotypes associated with variants in these ALS and FTD genes. It is hoped that the large sequencing initiatives currently underway in ALS and FTD will begin to uncover why different diseases are associated with mutations within a single gene, especially as a personalized medicine approach to therapy, based on a patient's genetics, approaches the clinic.
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Affiliation(s)
- Ramya Ranganathan
- Sheffield Institute for Translational Neuroscience (SITraN), The University of Sheffield, Sheffield, United Kingdom
| | - Shaila Haque
- Sheffield Institute for Translational Neuroscience (SITraN), The University of Sheffield, Sheffield, United Kingdom
- Department of Biochemistry and Biotechnology, University of Barishal, Barishal, Bangladesh
| | - Kayesha Coley
- Sheffield Institute for Translational Neuroscience (SITraN), The University of Sheffield, Sheffield, United Kingdom
| | - Stephanie Shepheard
- Sheffield Institute for Translational Neuroscience (SITraN), The University of Sheffield, Sheffield, United Kingdom
| | - Johnathan Cooper-Knock
- Sheffield Institute for Translational Neuroscience (SITraN), The University of Sheffield, Sheffield, United Kingdom
| | - Janine Kirby
- Sheffield Institute for Translational Neuroscience (SITraN), The University of Sheffield, Sheffield, United Kingdom
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28
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Wu JJ, Cai A, Greenslade JE, Higgins NR, Fan C, Le NTT, Tatman M, Whiteley AM, Prado MA, Dieriks BV, Curtis MA, Shaw CE, Siddique T, Faull RLM, Scotter EL, Finley D, Monteiro MJ. ALS/FTD mutations in UBQLN2 impede autophagy by reducing autophagosome acidification through loss of function. Proc Natl Acad Sci U S A 2020; 117:15230-15241. [PMID: 32513711 PMCID: PMC7334651 DOI: 10.1073/pnas.1917371117] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mutations in UBQLN2 cause amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and other neurodegenerations. However, the mechanism by which the UBQLN2 mutations cause disease remains unclear. Alterations in proteins involved in autophagy are prominent in neuronal tissue of human ALS UBQLN2 patients and in a transgenic P497S UBQLN2 mouse model of ALS/FTD, suggesting a pathogenic link. Here, we show UBQLN2 functions in autophagy and that ALS/FTD mutant proteins compromise this function. Inactivation of UBQLN2 expression in HeLa cells reduced autophagic flux and autophagosome acidification. The defect in acidification was rescued by reexpression of wild type (WT) UBQLN2 but not by any of the five different UBQLN2 ALS/FTD mutants tested. Proteomic analysis and immunoblot studies revealed P497S mutant mice and UBQLN2 knockout HeLa and NSC34 cells have reduced expression of ATP6v1g1, a critical subunit of the vacuolar ATPase (V-ATPase) pump. Knockout of UBQLN2 expression in HeLa cells decreased turnover of ATP6v1g1, while overexpression of WT UBQLN2 increased biogenesis of ATP6v1g1 compared with P497S mutant UBQLN2 protein. In vitro interaction studies showed that ATP6v1g1 binds more strongly to WT UBQLN2 than to ALS/FTD mutant UBQLN2 proteins. Intriguingly, overexpression of ATP6v1g1 in UBQLN2 knockout HeLa cells increased autophagosome acidification, suggesting a therapeutic approach to overcome the acidification defect. Taken together, our findings suggest that UBQLN2 mutations drive pathogenesis through a dominant-negative loss-of-function mechanism in autophagy and that UBQLN2 functions as an important regulator of the expression and stability of ATP6v1g1. These findings may have important implications for devising therapies to treat UBQLN2-linked ALS/FTD.
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Affiliation(s)
- Josephine J Wu
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Ashley Cai
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Jessie E Greenslade
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Nicole R Higgins
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Cong Fan
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Nhat T T Le
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Micaela Tatman
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | | | - Miguel A Prado
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Birger V Dieriks
- Department of Anatomy and Medical Imaging, University of Auckland, 1010 Auckland, New Zealand
- Centre for Brain Research, University of Auckland, 1010 Auckland, New Zealand
| | - Maurice A Curtis
- Department of Anatomy and Medical Imaging, University of Auckland, 1010 Auckland, New Zealand
- Centre for Brain Research, University of Auckland, 1010 Auckland, New Zealand
| | - Christopher E Shaw
- United Kingdom Dementia Research Institute, King's College London, WC2R 2LS London, United Kingdom
- Maurice Wohl Clinical Neuroscience Institute, King's College London, SE5 9RT London, United Kingdom
- Institute of Psychiatry, Psychology, and Neuroscience, King's College London, WC2R 2LS London, United Kingdom
| | - Teepu Siddique
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Richard L M Faull
- Department of Anatomy and Medical Imaging, University of Auckland, 1010 Auckland, New Zealand
- Centre for Brain Research, University of Auckland, 1010 Auckland, New Zealand
| | - Emma L Scotter
- Centre for Brain Research, University of Auckland, 1010 Auckland, New Zealand
- Department of Pharmacology and Clinical Pharmacology, University of Auckland, 1010 Auckland, New Zealand
| | - Daniel Finley
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Mervyn J Monteiro
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201;
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29
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UBQLN2 Promotes the Production of Type I Interferon via the TBK1-IRF3 Pathway. Cells 2020; 9:cells9051205. [PMID: 32413959 PMCID: PMC7290724 DOI: 10.3390/cells9051205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 05/07/2020] [Accepted: 05/12/2020] [Indexed: 12/13/2022] Open
Abstract
Mutations of Ubiquilin 2 (UBQLN2) or TANK-binding kinase 1 (TBK1) are associated with amyotrophic lateral sclerosis and frontotemporal degeneration (ALS/FTD). However, the mechanisms whereby UBQLN2 or TBK1 mutations lead to ALS and FTD remain unclear. Here, we explored the effect of UBQLN2 on TBK1 in HEK-293T cells or in CRISPR-Cas9-mediated IRF3 and IRF7 knockout (KO) cells. We found an interaction between TBK1 and UBQLN2, which was affected by ALS/FTD-linked mutations in TBK1 or UBQLN2. Co-expression of UBQLN2 with TBK1 elevated the protein level of TBK1 as well as the phosphorylation of TBK1 and IRF3 in a UBQLN2 dose-dependent manner, and this phosphorylation was reduced by mutant UBQLN2. In addition, the cellular production of IFN1 and related pro-inflammatory cytokines was substantially elevated when UBQLN2 and TBK1 were co-expressed, which was also decreased by mutant UBQLN2. Functional assay revealed that mutant UBQLN2 significantly reduced the binding affinity of TBK1 for its partners, including IRF3, (SQSTM1)/p62 and optineurin (OPTN). Moreover, complete loss of IRF3 abolished the induction of IFN1 and related pro-inflammatory cytokines enhanced by UBQLN2 in HEK-293T cells, whereas no significant change in IRF7 knockout cells was observed. Thus, our findings suggest that UBQLN2 promotes IRF3 phosphorylation via TBK1, leading to enhanced IFN1 induction, and also imply that the dysregulated TBK1-IRF3 pathway may play a role in UBQLN2-related neurodegeneration.
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30
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Abstract
In this issue of Structure, Dao et al. (2019) report that ALS-linked mutations in the Pxx domain of Ubiquilin 2 (UBQLN2) differentially influence the protein's phase separation abilities. The affect is by reducing the temperature and UBQLN2 concentration necessary for liquid-liquid phase separation droplet formation and by modulating UBQLN2 oligomerization.
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Affiliation(s)
- Nicole Higgins
- The Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Brian Lin
- The Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Mervyn J Monteiro
- The Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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31
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Lee S, Jeon YM, Cha SJ, Kim S, Kwon Y, Jo M, Jang YN, Lee S, Kim J, Kim SR, Lee KJ, Lee SB, Kim K, Kim HJ. PTK2/FAK regulates UPS impairment via SQSTM1/p62 phosphorylation in TARDBP/TDP-43 proteinopathies. Autophagy 2019; 16:1396-1412. [PMID: 31690171 DOI: 10.1080/15548627.2019.1686729] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
TARDBP/TDP-43 (TAR DNA binding protein) proteinopathies are a common feature in a variety of neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration (FTLD), and Alzheimer disease (AD). However, the molecular mechanisms underlying TARDBP-induced neurotoxicity are largely unknown. In this study, we demonstrated that TARDBP proteinopathies induce impairment in the ubiquitin proteasome system (UPS), as evidenced by an accumulation of ubiquitinated proteins and a reduction in proteasome activity in neuronal cells. Through kinase inhibitor screening, we identified PTK2/FAK (PTK2 protein tyrosine kinase 2) as a suppressor of neurotoxicity induced by UPS impairment. Importantly, PTK2 inhibition significantly reduced ubiquitin aggregates and attenuated TARDBP-induced cytotoxicity in a Drosophila model of TARDBP proteinopathies. We further identified that phosphorylation of SQSTM1/p62 (sequestosome 1) at S403 (p-SQSTM1 [S403]), a key component in the autophagic degradation of poly-ubiquitinated proteins, is increased upon TARDBP overexpression and is dependent on the activation of PTK2 in neuronal cells. Moreover, expressing a non-phosphorylated form of SQSTM1 (SQSTM1S403A) significantly repressed the accumulation of insoluble poly-ubiquitinated proteins and neurotoxicity induced by TARDBP overexpression in neuronal cells. In addition, TBK1 (TANK binding kinase 1), a kinase that phosphorylates S403 of SQSTM1, was found to be involved in the PTK2-mediated phosphorylation of SQSTM1. Taken together, our data suggest that the PTK2-TBK1-SQSTM1 axis plays a critical role in the pathogenesis of TARDBP by regulating neurotoxicity induced by UPS impairment. Therefore, targeting the PTK2-TBK1-SQSTM1 axis may represent a novel therapeutic intervention for neurodegenerative diseases with TARDBP proteinopathies.Abbreviations: ALP: macroautophagy/autophagy lysosomal pathway; ALS: amyotrophic lateral sclerosis; ATXN2: ataxin 2; BafA1: bafilomycin A1; cCASP3: cleaved caspase 3; CSNK2: casein kinase 2; FTLD: frontotemporal lobar degeneration; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; OPTN: optineurin; PTK2/FAK: PTK2 protein tyrosine kinase 2; SQSTM1/p62: sequestosome 1; TARDBP/TDP-43: TAR DNA binding protein; TBK1: TANK binding kinase 1; ULK1: unc-51 like autophagy activating kinase 1; UPS: ubiquitin-proteasome system.
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Affiliation(s)
- Shinrye Lee
- Dementia Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea
| | - Yu-Mi Jeon
- Dementia Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea
| | - Sun Joo Cha
- Soonchunhyang Institute of Medi-bio Science, Soonchunhyang University , Cheonan, South Korea
| | - Seyeon Kim
- Dementia Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea.,Department of Brain & Cognitive Sciences, DGIST , Daegu, South Korea
| | - Younghwi Kwon
- Dementia Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea.,Department of Brain & Cognitive Sciences, DGIST , Daegu, South Korea
| | - Myungjin Jo
- Dementia Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea
| | - You-Na Jang
- Neural circuits Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea
| | - Seongsoo Lee
- Gwangju Center, Korea Basic Science Institute (KBSI) , Gwangju, South Korea
| | - Jaekwang Kim
- Dementia Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea
| | - Sang Ryong Kim
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Institute of Life Science & Biotechnology, Kyungpook National University , Daegu, South Korea.,Brain Science and Engineering Institute, Kyungpook National University , Daegu, South Korea
| | - Kea Joo Lee
- Neural circuits Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea
| | - Sung Bae Lee
- Department of Brain & Cognitive Sciences, DGIST , Daegu, South Korea
| | - Kiyoung Kim
- Soonchunhyang Institute of Medi-bio Science, Soonchunhyang University , Cheonan, South Korea.,Department of Medical Biotechnology, Soonchunhyang University , Asan, South Korea
| | - Hyung-Jun Kim
- Dementia Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea
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32
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Renaud L, Picher-Martel V, Codron P, Julien JP. Key role of UBQLN2 in pathogenesis of amyotrophic lateral sclerosis and frontotemporal dementia. Acta Neuropathol Commun 2019; 7:103. [PMID: 31319884 PMCID: PMC6889556 DOI: 10.1186/s40478-019-0758-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 06/22/2019] [Indexed: 12/11/2022] Open
Abstract
Ubiquilin-2 (UBQLN2) is a member of the ubiquilin family, actively implicated in the degradation of misfolded and redundant proteins through the ubiquitin-proteasome system and macroautophagy. UBQLN2 received much attention after the discovery of gene mutations in amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD). The abnormal presence of positive UBQLN2 inclusion in the cytosol of degenerating motor neurons of familial and sporadic forms of ALS patients has been newly related to neurodegeneration. Only recently, data have emerged on its role in liquid-liquid phase separation, in stress granule development and in the formation of secondary amyloid structures. Furthermore, several animal models are available to investigate its involvement in TDP-43 pathology and neuroinflammation in ALS. This review addresses the molecular pathogenetic pathways involving UBQLN2 abnormalities which are converging toward defects in clearance mechanisms. UBQLN2.
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33
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Harman CA, Monteiro MJ. The specificity of ubiquitin binding to ubiquilin-1 is regulated by sequences besides its UBA domain. Biochim Biophys Acta Gen Subj 2019; 1863:1568-1574. [PMID: 31175912 DOI: 10.1016/j.bbagen.2019.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/24/2019] [Accepted: 06/03/2019] [Indexed: 12/12/2022]
Abstract
UBQLN proteins regulate proteostasis by facilitating clearance of misfolded proteins through the proteasome and autophagy degradation pathways. Consistent with its proteasomal function, UBQLN proteins contain both UBL and UBA domains, which bind subunits of the proteasome, including the S5a subunit, and ubiquitin chains, respectively. Conclusions regarding the binding properties of UBQLN proteins have been derived principally through studies of its individual domains, not the full-length (FL) proteins. Here we describe the in vitro binding properties of FL-UBQLN1 with the S5a subunit of the proteasome and two different lysine-linked (K48 or K63) ubiquitin chains. We show that in contrast to its isolated UBA domain, which binds almost equally well with both K48 and K63 ubiquitin chains, FL UBQLN1 binds preferentially with K63 chains. Furthermore, we show that deletion of the UBL domain from UBQLN1 abrogates ubiquitin binding. Taken together these results suggest that sequences outside of the UBA domain in UBQLN1 function to regulate the specificity and binding with different ubiquitin moieties. We also show that the UBL domain of UBQLN1 is required for S5a binding and that its binding to UBQLN1, in turn, enhances K48 ubiquitin chain binding to the complex. We discuss the implications of our findings with the known function of UBQLN proteins in protein degradation.
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Affiliation(s)
- Christine A Harman
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States.
| | - Mervyn J Monteiro
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States.
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Burk K, Pasterkamp RJ. Disrupted neuronal trafficking in amyotrophic lateral sclerosis. Acta Neuropathol 2019; 137:859-877. [PMID: 30721407 PMCID: PMC6531423 DOI: 10.1007/s00401-019-01964-7] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 01/19/2019] [Accepted: 01/19/2019] [Indexed: 02/07/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive, adult-onset neurodegenerative disease caused by degeneration of motor neurons in the brain and spinal cord leading to muscle weakness. Median survival after symptom onset in patients is 3-5 years and no effective therapies are available to treat or cure ALS. Therefore, further insight is needed into the molecular and cellular mechanisms that cause motor neuron degeneration and ALS. Different ALS disease mechanisms have been identified and recent evidence supports a prominent role for defects in intracellular transport. Several different ALS-causing gene mutations (e.g., in FUS, TDP-43, or C9ORF72) have been linked to defects in neuronal trafficking and a picture is emerging on how these defects may trigger disease. This review summarizes and discusses these recent findings. An overview of how endosomal and receptor trafficking are affected in ALS is followed by a description on dysregulated autophagy and ER/Golgi trafficking. Finally, changes in axonal transport and nucleocytoplasmic transport are discussed. Further insight into intracellular trafficking defects in ALS will deepen our understanding of ALS pathogenesis and will provide novel avenues for therapeutic intervention.
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Affiliation(s)
- Katja Burk
- Department of Neurologie, Universitätsmedizin Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.
- Center for Biostructural Imaging of Neurodegeneration, Von-Siebold-Str. 3A, 37075, Göttingen, Germany.
| | - R Jeroen Pasterkamp
- Department of Translational Neuroscience, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Universiteitsweg 100, 3584 CG, Utrecht, The Netherlands.
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35
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Meng T, Lin S, Zhuang H, Huang H, He Z, Hu Y, Gong Q, Feng D. Recent progress in the role of autophagy in neurological diseases. Cell Stress 2019; 3:141-161. [PMID: 31225510 PMCID: PMC6551859 DOI: 10.15698/cst2019.05.186] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Autophagy (here refers to macroautophagy) is a catabolic pathway by which large protein aggregates and damaged organelles are first sequestered into a double-membraned structure called autophago-some and then delivered to lysosome for destruction. Recently, tremen-dous progress has been made to elucidate the molecular mechanism and functions of this essential cellular metabolic process. In addition to being either a rubbish clearing system or a cellular surviving program in response to different stresses, autophagy plays important roles in a large number of pathophysiological conditions, such as cancer, diabetes, and especially neurodegenerative disorders. Here we review recent progress in the role of autophagy in neurological diseases and discuss how dysregulation of autophagy initiation, autophagosome formation, maturation, and/or au-tophagosome-lysosomal fusion step contributes to the pathogenesis of these disorders in the nervous system.
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Affiliation(s)
- Tian Meng
- State Key Laboratory of Respiratory Disease, School of Basic Medical Sciences, Guangzhou Medical University; Affiliated Cancer Hospital of Guangzhou Medical University, Guangzhou 511436, China
| | - Shiyin Lin
- State Key Laboratory of Respiratory Disease, School of Basic Medical Sciences, Guangzhou Medical University; Affiliated Cancer Hospital of Guangzhou Medical University, Guangzhou 511436, China
| | - Haixia Zhuang
- State Key Laboratory of Respiratory Disease, School of Basic Medical Sciences, Guangzhou Medical University; Affiliated Cancer Hospital of Guangzhou Medical University, Guangzhou 511436, China
| | - Haofeng Huang
- Institute of Neurology, Guangdong Key Laboratory of Age-Related Cardiac-Cerebral Vascular Disease, Affiliated Hospital of Guangdong Medical College, Zhanjiang, Guangdong, China
| | - Zhengjie He
- State Key Laboratory of Respiratory Disease, School of Basic Medical Sciences, Guangzhou Medical University; Affiliated Cancer Hospital of Guangzhou Medical University, Guangzhou 511436, China
| | - Yongquan Hu
- State Key Laboratory of Respiratory Disease, School of Basic Medical Sciences, Guangzhou Medical University; Affiliated Cancer Hospital of Guangzhou Medical University, Guangzhou 511436, China
| | - Qing Gong
- Department of Biochemistry and Molecular Biology, GMU-GIBH Joint School of Life Sciences, Guangzhou Medical University, Guangzhou 511436, People's Republic of China
| | - Du Feng
- State Key Laboratory of Respiratory Disease, School of Basic Medical Sciences, Guangzhou Medical University; Affiliated Cancer Hospital of Guangzhou Medical University, Guangzhou 511436, China
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36
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ALS-Linked Mutations Affect UBQLN2 Oligomerization and Phase Separation in a Position- and Amino Acid-Dependent Manner. Structure 2019; 27:937-951.e5. [PMID: 30982635 DOI: 10.1016/j.str.2019.03.012] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 12/22/2018] [Accepted: 03/15/2019] [Indexed: 12/14/2022]
Abstract
Proteasomal shuttle factor UBQLN2 is recruited to stress granules and undergoes liquid-liquid phase separation (LLPS) into protein-containing droplets. Mutations to UBQLN2 have recently been shown to cause dominant X-linked inheritance of amyotrophic lateral sclerosis (ALS) and ALS/dementia. Interestingly, most of these UBQLN2 mutations reside in its proline-rich (Pxx) region, an important modulator of LLPS. Here, we demonstrated that ALS-linked Pxx mutations differentially affect UBQLN2 LLPS, depending on both amino acid substitution and sequence position. Using size-exclusion chromatography, analytical ultracentrifugation, microscopy, and NMR spectroscopy, we determined that those Pxx mutants that enhanced UBQLN2 oligomerization decreased saturation concentrations needed for LLPS and promoted solid-like and viscoelastic morphological changes to UBQLN2 liquid assemblies. Ubiquitin disassembled all LLPS-induced mutant UBQLN2 aggregates. We postulate that the changes in physical properties caused by ALS-linked Pxx mutations modify UBQLN2 behavior in vivo, possibly contributing to aberrant stress granule morphology and dynamics, leading to formation of inclusions, pathological characteristics of ALS.
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37
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Kim SH, Stiles SG, Feichtmeier JM, Ramesh N, Zhan L, Scalf MA, Smith LM, Pandey UB, Tibbetts RS. Mutation-dependent aggregation and toxicity in a Drosophila model for UBQLN2-associated ALS. Hum Mol Genet 2019; 27:322-337. [PMID: 29161404 DOI: 10.1093/hmg/ddx403] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 11/14/2017] [Indexed: 12/12/2022] Open
Abstract
Members of the conserved ubiquilin (UBQLN) family of ubiquitin (Ub) chaperones harbor an antipodal UBL (Ub-like)-UBA (Ub-associated) domain arrangement and participate in proteasome and autophagosome-mediated protein degradation. Mutations in a proline-rich-repeat region (PRR) of UBQLN2 cause amyotrophic lateral sclerosis (ALS)/frontotemporal dementia (FTD); however, neither the normal functions of the PRR nor impacts of ALS-associated mutations within it are well understood. In this study, we show that ALS mutations perturb UBQLN2 solubility and folding in a mutation-specific manner. Biochemical impacts of ALS mutations were additive, transferable to UBQLN1, and resulted in enhanced Ub association. A Drosophila melanogaster model for UBQLN2-associated ALS revealed that both wild-type and ALS-mutant UBQLN2 alleles disrupted Ub homeostasis; however, UBQLN2ALS mutants exhibited age-dependent aggregation and caused toxicity phenotypes beyond those seen for wild-type UBQLN2. Although UBQLN2 toxicity was not correlated with aggregation in the compound eye, aggregation-prone UBQLN2 mutants elicited climbing defects and neuromuscular junctions (NMJ) abnormalities when expressed in neurons. An UBA domain mutation that abolished Ub binding also diminished UBQLN2 toxicity, implicating Ub binding in the underlying pathomechanism. We propose that ALS-associated mutations in UBQLN2 disrupt folding and that both aggregated species and soluble oligomers instigate neuron autonomous toxicity through interference with Ub homeostasis.
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Affiliation(s)
- Sang Hwa Kim
- Department of Human Oncology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA
| | - Shannon G Stiles
- Department of Human Oncology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA
| | - Joseph M Feichtmeier
- Department of Human Oncology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA
| | - Nandini Ramesh
- Department of Pediatrics, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
| | - Lihong Zhan
- Department of Human Oncology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA
| | - Mark A Scalf
- Department of Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA
| | - Lloyd M Smith
- Department of Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA
| | - Udai Bhan Pandey
- Department of Pediatrics, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
| | - Randal S Tibbetts
- Department of Human Oncology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA
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38
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RNA Granules and Their Role in Neurodegenerative Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1203:195-245. [DOI: 10.1007/978-3-030-31434-7_8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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39
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Ubiquilin 2 modulates ALS/FTD-linked FUS-RNA complex dynamics and stress granule formation. Proc Natl Acad Sci U S A 2018; 115:E11485-E11494. [PMID: 30442662 DOI: 10.1073/pnas.1811997115] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The ubiquitin-like protein ubiquilin 2 (UBQLN2) has been genetically and pathologically linked to the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), but its normal cellular functions are not well understood. In a search for UBQLN2-interacting proteins, we found an enrichment of stress granule (SG) components, including ALS/FTD-linked heterogeneous ribonucleoprotein fused in sarcoma (FUS). Through the use of an optimized SG detection method, we observed UBQLN2 and its interactors at SGs. A low complexity, Sti1-like repeat region in UBQLN2 was sufficient for its localization to SGs. Functionally, UBQLN2 negatively regulated SG formation. UBQLN2 increased the dynamics of FUS-RNA interaction and promoted the fluidity of FUS-RNA complexes at a single-molecule level. This solubilizing effect corresponded to a dispersal of FUS liquid droplets in vitro and a suppression of FUS SG formation in cells. ALS-linked mutations in UBQLN2 reduced its association with FUS and impaired its function in regulating FUS-RNA complex dynamics and SG formation. These results reveal a previously unrecognized role for UBQLN2 in regulating the early stages of liquid-liquid phase separation by directly modulating the fluidity of protein-RNA complexes and the dynamics of SG formation.
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40
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Picher-Martel V, Renaud L, Bareil C, Julien JP. Neuronal Expression of UBQLN2 P497H Exacerbates TDP-43 Pathology in TDP-43 G348C Mice through Interaction with Ubiquitin. Mol Neurobiol 2018; 56:4680-4696. [PMID: 30377984 PMCID: PMC6647471 DOI: 10.1007/s12035-018-1411-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 10/24/2018] [Indexed: 12/11/2022]
Abstract
Mutations in the gene encoding ubiquilin-2 (UBQLN2) are linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). UBQLN2 plays a central role in ubiquitin proteasome system (UPS) and UBQLN2 up-regulation exacerbates TDP-43 cytoplasmic aggregates. To analyze interaction between UBQLN2 and TDP-43 and to produce a relevant ALS animal model, we have generated a new transgenic mouse expressing UBQLN2P497H under the neurofilament heavy (NFH) gene promoter. The UBQLN2P497H mice were then bred with our previously described TDP-43G348C mice to generate double-transgenic UBQLN2P497H; TDP-43G348C mice. With low-expression levels of UBQLN2, the double-transgenic mice developed TDP-43 cytosolic accumulations in motor neurons starting at 5 months of age. These double-transgenic mice exhibited motor neuron loss, muscle atrophy, as well as motor and cognitive deficits during aging. The microglia from double-transgenic mice were hyperresponsive to intraperitoneal injection of lipopolysaccharide (LPS). In vivo and in vitro analyses suggested that extra UBQLN2 proteins can exacerbate cytoplasmic TDP-43 accumulations by competing with the UPS for binding to ubiquitin. Thus, increasing the pool of ubiquitin promoted the UPS function with ensuing reduction of TDP-43 cytosolic accumulations. In conclusion, the double-transgenic UBQLN2P497H; TDP-43G348C mice provides a unique mouse model of ALS/FTD with enhanced TDP-43 pathology that can be exploited for drug testing.
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Affiliation(s)
- Vincent Picher-Martel
- Department of Psychiatry and Neuroscience, Laval University, Quebec, Canada.,CERVO Brain Research Centre, 2601 Chemin de la Canardière, Québec, QC, G1J 2G3, Canada
| | - Laurence Renaud
- Department of Psychiatry and Neuroscience, Laval University, Quebec, Canada.,CERVO Brain Research Centre, 2601 Chemin de la Canardière, Québec, QC, G1J 2G3, Canada
| | - Christine Bareil
- CERVO Brain Research Centre, 2601 Chemin de la Canardière, Québec, QC, G1J 2G3, Canada
| | - Jean-Pierre Julien
- Department of Psychiatry and Neuroscience, Laval University, Quebec, Canada. .,CERVO Brain Research Centre, 2601 Chemin de la Canardière, Québec, QC, G1J 2G3, Canada.
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41
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Kurtishi A, Rosen B, Patil KS, Alves GW, Møller SG. Cellular Proteostasis in Neurodegeneration. Mol Neurobiol 2018; 56:3676-3689. [PMID: 30182337 DOI: 10.1007/s12035-018-1334-z] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 08/27/2018] [Indexed: 02/06/2023]
Abstract
The term proteostasis reflects the fine-tuned balance of cellular protein levels, mediated through a vast network of biochemical pathways. This requires the regulated control of protein folding, post-translational modification, and protein degradation. Due to the complex interactions and intersection of proteostasis pathways, exposure to stress conditions may lead to a disruption of the entire network. Incorrect protein folding and/or modifications during protein synthesis results in inactive or toxic proteins, which may overload degradation mechanisms. Further, a disruption of autophagy and the endoplasmic reticulum degradation pathway may result in additional cellular stress which could ultimately lead to cell death. Neurodegenerative diseases such as Parkinson's disease, Alzheimer's disease, Huntington's disease, and Amyotrophic Lateral Sclerosis all share common risk factors such as oxidative stress, aging, environmental stress, and protein dysfunction; all of which alter cellular proteostasis. The differing pathologies observed in neurodegenerative diseases are determined by factors such as location-specific neuronal death, source of protein dysfunction, and the cell's ability to counter proteotoxicity. In this review, we discuss how the disruption in cellular proteostasis contributes to the onset and progression of neurodegenerative diseases.
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Affiliation(s)
- Alberim Kurtishi
- Department of Biological Sciences, St. John's University, 8000 Utopia Parkway, New York, 11439, USA
| | - Benjamin Rosen
- Department of Biological Sciences, St. John's University, 8000 Utopia Parkway, New York, 11439, USA
| | - Ketan S Patil
- Department of Biological Sciences, St. John's University, 8000 Utopia Parkway, New York, 11439, USA
| | - Guido W Alves
- Norwegian Center for Movement Disorders, Stavanger University Hospital, Stavanger, Norway
| | - Simon G Møller
- Department of Biological Sciences, St. John's University, 8000 Utopia Parkway, New York, 11439, USA. .,Norwegian Center for Movement Disorders, Stavanger University Hospital, Stavanger, Norway.
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42
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Ito D, Hatano M, Suzuki N. RNA binding proteins and the pathological cascade in ALS/FTD neurodegeneration. Sci Transl Med 2018; 9:9/415/eaah5436. [PMID: 29118263 DOI: 10.1126/scitranslmed.aah5436] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 10/13/2016] [Accepted: 04/13/2017] [Indexed: 12/12/2022]
Abstract
Advanced genetic approaches have accelerated the identification of causative genes linked to the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Most of the disease-related proteins encoded by these genes form aggregates in the cellular machineries that regulate RNA and protein quality control in cells. Cross-talk among the signaling pathways governing these machineries leads to pathological cascades mediated by the accumulation of mutant RNA binding proteins. We outline the molecular basis of ALS and FTD pathogenesis and discuss the prospects for therapeutic strategies to treat these diseases.
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Affiliation(s)
- Daisuke Ito
- Department of Neurology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan.
| | - Mami Hatano
- Department of Pathology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Norihiro Suzuki
- Department of Neurology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
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43
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Abstract
Under stress, certain eukaryotic proteins and RNA assemble to form membraneless organelles known as stress granules. The most well-studied stress granule components are RNA-binding proteins that undergo liquid-liquid phase separation (LLPS) into protein-rich droplets mediated by intrinsically disordered low-complexity domains (LCDs). Here we show that stress granules include proteasomal shuttle factor UBQLN2, an LCD-containing protein structurally and functionally distinct from RNA-binding proteins. In vitro, UBQLN2 exhibits LLPS at physiological conditions. Deletion studies correlate oligomerization with UBQLN2's ability to phase-separate and form stress-induced cytoplasmic puncta in cells. Using nuclear magnetic resonance (NMR) spectroscopy, we mapped weak, multivalent interactions that promote UBQLN2 oligomerization and LLPS. Ubiquitin or polyubiquitin binding, obligatory for UBQLN2's biological functions, eliminates UBQLN2 LLPS, thus serving as a switch between droplet and disperse phases. We postulate that UBQLN2 LLPS enables its recruitment to stress granules, where its interactions with ubiquitinated substrates reverse LLPS to enable shuttling of clients out of stress granules.
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44
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Chen H, Kankel MW, Su SC, Han SWS, Ofengeim D. Exploring the genetics and non-cell autonomous mechanisms underlying ALS/FTLD. Cell Death Differ 2018; 25:648-662. [PMID: 29459769 DOI: 10.1038/s41418-018-0060-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 11/27/2017] [Accepted: 11/28/2017] [Indexed: 12/11/2022] Open
Abstract
Although amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, was first described in 1874, a flurry of genetic discoveries in the last 10 years has markedly increased our understanding of this disease. These findings have not only enhanced our knowledge of mechanisms leading to ALS, but also have revealed that ALS shares many genetic causes with another neurodegenerative disease, frontotemporal lobar dementia (FTLD). In this review, we survey how recent genetic studies have bridged our mechanistic understanding of these two related diseases and how the genetics behind ALS and FTLD point to complex disorders, implicating non-neuronal cell types in disease pathophysiology. The involvement of non-neuronal cell types is consistent with a non-cell autonomous component in these diseases. This is further supported by studies that identified a critical role of immune-associated genes within ALS/FTLD and other neurodegenerative disorders. The molecular functions of these genes support an emerging concept that various non-autonomous functions are involved in neurodegeneration. Further insights into such a mechanism(s) will ultimately lead to a better understanding of potential routes of therapeutic intervention. Facts ALS and FTLD are severe neurodegenerative disorders on the same disease spectrum. Multiple cellular processes including dysregulation of RNA homeostasis, imbalance of proteostasis, contribute to ALS/FTLD pathogenesis. Aberrant function in non-neuronal cell types, including microglia, contributes to ALS/FTLD. Strong neuroimmune and neuroinflammatory components are associated with ALS/FTLD patients. Open Questions Why can patients with similar mutations have different disease manifestations, i.e., why do C9ORF72 mutations lead to motor neuron loss in some patients while others exhibit loss of neurons in the frontotemporal lobe? Do ALS causal mutations result in microglial dysfunction and contribute to ALS/FTLD pathology? How do microglia normally act to mitigate neurodegeneration in ALS/FTLD? To what extent do cellular signaling pathways mediate non-cell autonomous communications between distinct central nervous system (CNS) cell types during disease? Is it possible to therapeutically target specific cell types in the CNS?
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Affiliation(s)
- Hongbo Chen
- Department of Pediatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA, 02115, USA
| | - Mark W Kankel
- Biogen Inc., 225 Binney Street, Cambridge, MA, 02142, USA
| | - Susan C Su
- Biogen Inc., 225 Binney Street, Cambridge, MA, 02142, USA
| | - Steve W S Han
- Biogen Inc., 225 Binney Street, Cambridge, MA, 02142, USA.,Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.,GSK, Upper Providence, PA, 19426, USA
| | - Dimitry Ofengeim
- Biogen Inc., 225 Binney Street, Cambridge, MA, 02142, USA. .,Sanofi Neuroscience, Framingham, MA, USA.
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45
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Maurel C, Dangoumau A, Marouillat S, Brulard C, Chami A, Hergesheimer R, Corcia P, Blasco H, Andres CR, Vourc'h P. Causative Genes in Amyotrophic Lateral Sclerosis and Protein Degradation Pathways: a Link to Neurodegeneration. Mol Neurobiol 2018; 55:6480-6499. [PMID: 29322304 DOI: 10.1007/s12035-017-0856-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 12/20/2017] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a disease caused by the degeneration of motor neurons (MNs) leading to progressive muscle weakness and atrophy. Several molecular pathways have been implicated, such as glutamate-mediated excitotoxicity, defects in cytoskeletal dynamics and axonal transport, disruption of RNA metabolism, and impairments in proteostasis. ALS is associated with protein accumulation in the cytoplasm of cells undergoing neurodegeneration, which is a hallmark of the disease. In this review, we focus on mechanisms of proteostasis, particularly protein degradation, and discuss how they are related to the genetics of ALS. Indeed, the genetic bases of the disease with the implication of more than 30 genes associated with familial ALS to date, together with the important increase in understanding of endoplasmic reticulum (ER) stress, proteasomal degradation, and autophagy, allow researchers to better understand the mechanisms underlying the selective death of motor neurons in ALS. It is clear that defects in proteostasis are involved in this type of cellular degeneration, but whether or not these mechanisms are primary causes or merely consequential remains to be clearly demonstrated. Novel cellular and animal models allowing chronic expression of mutant proteins, for example, are required. Further studies linking genetic discoveries in ALS to mechanisms of protein clearance will certainly be crucial in order to accelerate translational and clinical research towards new therapeutic targets and strategies.
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Affiliation(s)
- C Maurel
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - A Dangoumau
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - S Marouillat
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - C Brulard
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - A Chami
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - R Hergesheimer
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - P Corcia
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
- Service de Neurologie, CHRU de Tours, 37044, Tours, France
| | - H Blasco
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
- Service de Biochimie et de Biologie Moléculaire, CHRU de Tours, 37044, Tours, France
| | - C R Andres
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
- Service de Biochimie et de Biologie Moléculaire, CHRU de Tours, 37044, Tours, France
| | - P Vourc'h
- UMR INSERM U1253, Université de Tours, 37032, Tours, France.
- Service de Biochimie et de Biologie Moléculaire, CHRU de Tours, 37044, Tours, France.
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46
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Jantrapirom S, Lo Piccolo L, Yoshida H, Yamaguchi M. A new Drosophila model of Ubiquilin knockdown shows the effect of impaired proteostasis on locomotive and learning abilities. Exp Cell Res 2017; 362:461-471. [PMID: 29247619 DOI: 10.1016/j.yexcr.2017.12.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 12/08/2017] [Accepted: 12/09/2017] [Indexed: 12/12/2022]
Abstract
Ubiquilin (UBQLN) plays a crucial role in cellular proteostasis through its involvement in the ubiquitin proteasome system and autophagy. Mutations in the UBQLN2 gene have been implicated in amyotrophic lateral sclerosis (ALS) and ALS with frontotemporal lobar dementia (ALS/FTLD). Previous studies reported a key role for UBQLN in Alzheimer's disease (AD); however, the mechanistic involvement of UBQLN in other neurodegenerative diseases remains unclear. The genome of Drosophila contains a single UBQLN homolog (dUbqn) that shows high similarity to UBQLN1 and UBQLN2; therefore, the fly is a useful model for characterizing the role of UBQLN in vivo in neurological disorders affecting locomotion and learning abilities. We herein performed a phenotypic and molecular characterization of diverse dUbqn RNAi lines. We found that the depletion of dUbqn induced the accumulation of polyubiquitinated proteins and caused morphological defects in various tissues. Our results showed that structural defects in larval neuromuscular junctions, abdominal neuromeres, and mushroom bodies correlated with limited abilities in locomotion, learning, and memory. These results contribute to our understanding of the impact of impaired proteostasis in neurodegenerative diseases and provide a useful Drosophila model for the development of promising therapies for ALS and FTLD.
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Affiliation(s)
- Salinee Jantrapirom
- Department of Applied Biology Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Luca Lo Piccolo
- Department of Applied Biology Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Hideki Yoshida
- Department of Applied Biology Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan; The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Masamitsu Yamaguchi
- Department of Applied Biology Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan; The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
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47
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Hardiman O, Al-Chalabi A, Chio A, Corr EM, Logroscino G, Robberecht W, Shaw PJ, Simmons Z, van den Berg LH. Amyotrophic lateral sclerosis. Nat Rev Dis Primers 2017; 3:17071. [PMID: 28980624 DOI: 10.1038/nrdp.2017.71] [Citation(s) in RCA: 820] [Impact Index Per Article: 117.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease, is characterized by the degeneration of both upper and lower motor neurons, which leads to muscle weakness and eventual paralysis. Until recently, ALS was classified primarily within the neuromuscular domain, although new imaging and neuropathological data have indicated the involvement of the non-motor neuraxis in disease pathology. In most patients, the mechanisms underlying the development of ALS are poorly understood, although a subset of patients have familial disease and harbour mutations in genes that have various roles in neuronal function. Two possible disease-modifying therapies that can slow disease progression are available for ALS, but patient management is largely mediated by symptomatic therapies, such as the use of muscle relaxants for spasticity and speech therapy for dysarthria.
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Affiliation(s)
- Orla Hardiman
- Academic Unit of Neurology, Room 5.41 Trinity Biomedical Science Institute, Trinity College Dublin, Pearse Street, Dublin 2, Ireland
| | - Ammar Al-Chalabi
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Adriano Chio
- Rita Levi Montalcini Department of Neurosciences, University of Turin, Turin, Italy
| | - Emma M Corr
- Academic Unit of Neurology, Room 5.41 Trinity Biomedical Science Institute, Trinity College Dublin, Pearse Street, Dublin 2, Ireland
| | | | - Wim Robberecht
- KU Leuven-University of Leuven, University Hospitals Leuven, Department of Neurology, Leuven, Belgium
| | - Pamela J Shaw
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Zachary Simmons
- Department of Neurology, Milton S. Hershey Medical Center, Penn State Health, Hershey, Pennsylvania, USA
| | - Leonard H van den Berg
- Department of Neurology, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
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48
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Whiteley AM, Prado MA, Peng I, Abbas AR, Haley B, Paulo JA, Reichelt M, Katakam A, Sagolla M, Modrusan Z, Lee DY, Roose-Girma M, Kirkpatrick DS, McKenzie BS, Gygi SP, Finley D, Brown EJ. Ubiquilin1 promotes antigen-receptor mediated proliferation by eliminating mislocalized mitochondrial proteins. eLife 2017; 6. [PMID: 28933694 PMCID: PMC5608509 DOI: 10.7554/elife.26435] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 08/22/2017] [Indexed: 12/14/2022] Open
Abstract
Ubiquilins (Ubqlns) are a family of ubiquitin receptors that promote the delivery of hydrophobic and aggregated ubiquitinated proteins to the proteasome for degradation. We carried out a proteomic analysis of a B cell lymphoma-derived cell line, BJAB, that requires UBQLN1 for survival to identify UBQLN1 client proteins. When UBQLN1 expression was acutely inhibited, 120 mitochondrial proteins were enriched in the cytoplasm, suggesting that the accumulation of mitochondrial client proteins in the absence of UBQLN1 is cytostatic. Using a Ubqln1−/− mouse strain, we found that B cell receptor (BCR) ligation of Ubqln1−/− B cells led to a defect in cell cycle entry. As in BJAB cells, mitochondrial proteins accumulated in BCR-stimulated cells, leading to protein synthesis inhibition and cell cycle block. Thus, UBQLN1 plays an important role in clearing mislocalized mitochondrial proteins upon cell stimulation, and its absence leads to suppression of protein synthesis and cell cycle arrest.
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Affiliation(s)
- Alexandra M Whiteley
- Department of Infectious Disease, Genentech, South San Francisco, United States.,Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Miguel A Prado
- Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Ivan Peng
- Department of Translational Immunology, Genentech, South San Francisco, United States
| | - Alexander R Abbas
- Department of Bioinformatics, Genentech, South San Francisco, United States
| | - Benjamin Haley
- Department of Molecular Biology, Genentech, South San Francisco, United States
| | - Joao A Paulo
- Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Mike Reichelt
- Department of Pathology, Genentech, South San Francisco, United States
| | - Anand Katakam
- Department of Pathology, Genentech, South San Francisco, United States
| | - Meredith Sagolla
- Department of Pathology, Genentech, South San Francisco, United States
| | - Zora Modrusan
- Department of Microchemistry, Proteomics, and Lipidomics, Genentech, South San Francisco, United States
| | - Dong Yun Lee
- Department of Infectious Disease, Genentech, South San Francisco, United States
| | - Merone Roose-Girma
- Department of Microchemistry, Proteomics, and Lipidomics, Genentech, South San Francisco, United States
| | - Donald S Kirkpatrick
- Department of Microchemistry, Proteomics, and Lipidomics, Genentech, South San Francisco, United States
| | - Brent S McKenzie
- Department of Translational Immunology, Genentech, South San Francisco, United States
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Daniel Finley
- Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Eric J Brown
- Department of Infectious Disease, Genentech, South San Francisco, United States
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49
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Gao FB, Almeida S, Lopez-Gonzalez R. Dysregulated molecular pathways in amyotrophic lateral sclerosis-frontotemporal dementia spectrum disorder. EMBO J 2017; 36:2931-2950. [PMID: 28916614 DOI: 10.15252/embj.201797568] [Citation(s) in RCA: 133] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 07/15/2017] [Accepted: 08/30/2017] [Indexed: 12/11/2022] Open
Abstract
Frontotemporal dementia (FTD), the second most common form of dementia in people under 65 years of age, is characterized by progressive atrophy of the frontal and/or temporal lobes. FTD overlaps extensively with the motor neuron disease amyotrophic lateral sclerosis (ALS), especially at the genetic level. Both FTD and ALS can be caused by many mutations in the same set of genes; the most prevalent of these mutations is a GGGGCC repeat expansion in the first intron of C9ORF72 As shown by recent intensive studies, some key cellular pathways are dysregulated in the ALS-FTD spectrum disorder, including autophagy, nucleocytoplasmic transport, DNA damage repair, pre-mRNA splicing, stress granule dynamics, and others. These exciting advances reveal the complexity of the pathogenic mechanisms of FTD and ALS and suggest promising molecular targets for future therapeutic interventions in these devastating disorders.
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Affiliation(s)
- Fen-Biao Gao
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Sandra Almeida
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA
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50
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Teyssou E, Chartier L, Amador MDM, Lam R, Lautrette G, Nicol M, Machat S, Da Barroca S, Moigneu C, Mairey M, Larmonier T, Saker S, Dussert C, Forlani S, Fontaine B, Seilhean D, Bohl D, Boillée S, Meininger V, Couratier P, Salachas F, Stevanin G, Millecamps S. Novel UBQLN2 mutations linked to amyotrophic lateral sclerosis and atypical hereditary spastic paraplegia phenotype through defective HSP70-mediated proteolysis. Neurobiol Aging 2017; 58:239.e11-239.e20. [PMID: 28716533 DOI: 10.1016/j.neurobiolaging.2017.06.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 06/14/2017] [Accepted: 06/20/2017] [Indexed: 11/26/2022]
Abstract
Mutations in UBQLN2 have been associated with rare cases of X-linked juvenile and adult forms of amyotrophic lateral sclerosis (ALS) and ALS linked to frontotemporal dementia (FTD). Here, we report 1 known (c.1489C>T, p.Pro497Ser, P497S) and 3 novel (c.1481C>T, p.Pro494Leu, P494L; c.1498C>T, p.Pro500Ser, P500S; and c.1516C>G, p.Pro506Ala, P506A) missense mutations in the PXX domain of UBQLN2 in familial motor neuron diseases including ALS and spastic paraplegia (SP). A novel missense mutation (c.1462G>A, p.Ala488Thr, A488T) adjacent to this hotspot UBQLN2 domain was identified in a sporadic case of ALS. These mutations are conserved in mammals, are absent from ExAC and gnomAD browsers, and are predicted to be deleterious by SIFT in silico analysis. Patient lymphoblasts carrying a UBQLN2 mutation showed absence of ubiquilin-2 accumulation, disrupted binding with HSP70, and impaired autophagic pathway. Our results confirm the role of PXX repeat in ALS pathogenesis, show that UBQLN2-linked disease can manifest like a SP phenotype, evidence a highly reduced disease penetrance in females carrying UBQLN2 mutations, which is important information for genetic counseling, and underline the pivotal role of ubiquilin-2 in proteolysis regulation pathways.
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Affiliation(s)
- Elisa Teyssou
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Laura Chartier
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Maria-Del-Mar Amador
- Département de Neurologie, Assistance Publique Hôpitaux de Paris (APHP), Centre de ressources et de compétences SLA Ile de France, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Roselina Lam
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Géraldine Lautrette
- Service de Neurologie, Centre de ressources et de compétences SLA, CHU Dupuytren, Limoges, France
| | - Marie Nicol
- Service de Neurologie, Centre de ressources et de compétences SLA, CHU Dupuytren, Limoges, France
| | - Selma Machat
- Service de Neurologie, Centre de ressources et de compétences SLA, CHU Dupuytren, Limoges, France
| | - Sandra Da Barroca
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Carine Moigneu
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Mathilde Mairey
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Ecole Pratique des Hautes Etudes, EPHE, Université de recherche Paris Sciences et Lettres, Paris, France
| | | | - Safaa Saker
- Banque d'ADN et de cellules du Généthon, Evry, France
| | - Christelle Dussert
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Sylvie Forlani
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Bertrand Fontaine
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Département de Neurologie, Assistance Publique Hôpitaux de Paris (APHP), Centre de ressources et de compétences SLA Ile de France, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Danielle Seilhean
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Département de Neuropathologie, APHP, Hôpital Pitié-Salpêtrière, Paris, France
| | - Delphine Bohl
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Séverine Boillée
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Vincent Meininger
- Département de Neurologie, Assistance Publique Hôpitaux de Paris (APHP), Centre de ressources et de compétences SLA Ile de France, Hôpital de la Pitié-Salpêtrière, Paris, France; Hôpital des Peupliers, Ramsay Générale de Santé, Paris, France
| | - Philippe Couratier
- Service de Neurologie, Centre de ressources et de compétences SLA, CHU Dupuytren, Limoges, France
| | - François Salachas
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Département de Neurologie, Assistance Publique Hôpitaux de Paris (APHP), Centre de ressources et de compétences SLA Ile de France, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Giovanni Stevanin
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Ecole Pratique des Hautes Etudes, EPHE, Université de recherche Paris Sciences et Lettres, Paris, France; Centre de Référence de Neurogénétique, Fédération de Génétique, APHP, Hôpital Pitié-Salpêtrière, Paris, France
| | - Stéphanie Millecamps
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France.
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