1
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Nguyen L. Updates on Disease Mechanisms and Therapeutics for Amyotrophic Lateral Sclerosis. Cells 2024; 13:888. [PMID: 38891021 PMCID: PMC11172142 DOI: 10.3390/cells13110888] [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: 03/29/2024] [Revised: 05/08/2024] [Accepted: 05/15/2024] [Indexed: 06/20/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease, is a motor neuron disease. In ALS, upper and lower motor neurons in the brain and spinal cord progressively degenerate during the course of the disease, leading to the loss of the voluntary movement of the arms and legs. Since its first description in 1869 by a French neurologist Jean-Martin Charcot, the scientific discoveries on ALS have increased our understanding of ALS genetics, pathology and mechanisms and provided novel therapeutic strategies. The goal of this review article is to provide a comprehensive summary of the recent findings on ALS mechanisms and related therapeutic strategies to the scientific audience. Several highlighted ALS research topics discussed in this article include the 2023 FDA approved drug for SOD1 ALS, the updated C9orf72 GGGGCC repeat-expansion-related mechanisms and therapeutic targets, TDP-43-mediated cryptic splicing and disease markers and diagnostic and therapeutic options offered by these recent discoveries.
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Affiliation(s)
- Lien Nguyen
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA;
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Genetics Institute, University of Florida, Gainesville, FL 32610, USA
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2
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Nelson AT, Cicardi ME, Markandaiah SS, Han JY, Philp NJ, Welebob E, Haeusler AR, Pasinelli P, Manfredi G, Kawamata H, Trotti D. Glucose hypometabolism prompts RAN translation and exacerbates C9orf72-related ALS/FTD phenotypes. EMBO Rep 2024; 25:2479-2510. [PMID: 38684907 PMCID: PMC11094177 DOI: 10.1038/s44319-024-00140-7] [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: 06/27/2023] [Revised: 04/04/2024] [Accepted: 04/09/2024] [Indexed: 05/02/2024] Open
Abstract
The most prevalent genetic cause of both amyotrophic lateral sclerosis and frontotemporal dementia is a (GGGGCC)n nucleotide repeat expansion (NRE) occurring in the first intron of the C9orf72 gene (C9). Brain glucose hypometabolism is consistently observed in C9-NRE carriers, even at pre-symptomatic stages, but its role in disease pathogenesis is unknown. Here, we show alterations in glucose metabolic pathways and ATP levels in the brains of asymptomatic C9-BAC mice. We find that, through activation of the GCN2 kinase, glucose hypometabolism drives the production of dipeptide repeat proteins (DPRs), impairs the survival of C9 patient-derived neurons, and triggers motor dysfunction in C9-BAC mice. We also show that one of the arginine-rich DPRs (PR) could directly contribute to glucose metabolism and metabolic stress by inhibiting glucose uptake in neurons. Our findings provide a potential mechanistic link between energy imbalances and C9-ALS/FTD pathogenesis and suggest a feedforward loop model with potential opportunities for therapeutic intervention.
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Affiliation(s)
- Andrew T Nelson
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Maria Elena Cicardi
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Shashirekha S Markandaiah
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - John Ys Han
- Department of Pathology and Genomic Medicine, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Nancy J Philp
- Department of Pathology and Genomic Medicine, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Emily Welebob
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Aaron R Haeusler
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Piera Pasinelli
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Giovanni Manfredi
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, 407 East 61st Street, New York, NY, 10065, USA
| | - Hibiki Kawamata
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, 407 East 61st Street, New York, NY, 10065, USA
| | - Davide Trotti
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, 19107, USA.
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3
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Zhao T, Duan S, Li J, Zheng H, Liu C, Zhang H, Luo H, Xu Y. Mapping of repeat-associated non-AUG (RAN) translation knowledge: A bibliometric analysis. Heliyon 2024; 10:e29141. [PMID: 38628764 PMCID: PMC11019168 DOI: 10.1016/j.heliyon.2024.e29141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 01/08/2024] [Accepted: 04/01/2024] [Indexed: 04/19/2024] Open
Abstract
Over 50 genetic human disorders are attributed to the irregular expansion of microsatellites. These expanded microsatellite sequences can experience bidirectional transcription, leading to new reading frames. Beyond the standard AUG initiation or adjacent start codons, they are translated into proteins characterized by disease-causing amino acid repeats through repeat-associated non-AUG translation. Despite its significance, there's a discernible gap in comprehensive and objective articles on RAN translation. This study endeavors to evaluate and delineate the contemporary landscape and progress of RAN translation research via a bibliometric analysis. We sourced literature on RAN translation from the Web of Science Core Collection. Utilizing two bibliometric analysis tools, CiteSpace and VOSviewer, we gauged individual impacts and interactions by examining annual publications, journals, co-cited journals, countries/regions, institutions, authors, and co-cited authors. Following this, we assessed the co-occurrence and bursts of keywords and co-cited references to pinpoint research hotspots and trending in RAN translation. Between 2011 and 2022, 1317 authors across 359 institutions from 34 countries/regions contributed to 250 publications on RAN translation, spread across 118 academic journals. This article presents a systematic, objective, and comprehensive analysis of the current literature on RAN translation. Our findings emphasize that mechanisms related to C9orf72 ALS/FTD are pivotal topics in the realm of RAN translation, with cellular stress and the utilization of small molecule marking the trending research areas.
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Affiliation(s)
- Taiqi Zhao
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
- Henan Key Laboratory of Cerebrovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Suying Duan
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
- Henan Key Laboratory of Cerebrovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Jiaqi Li
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
- Henan Key Laboratory of Cerebrovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Honglin Zheng
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
- The Academy of Medical Sciences of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Chenyang Liu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Hang Zhang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Haiyang Luo
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
- Henan Key Laboratory of Cerebrovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
- Institute of Neuroscience, Zhengzhou University, Zhengzhou, Henan, China
| | - Yuming Xu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
- Henan Key Laboratory of Cerebrovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
- Institute of Neuroscience, Zhengzhou University, Zhengzhou, Henan, China
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Martin EJ, Santacruz C, Mitevska A, Jones IE, Krishnan G, Gao FB, Finan JD, Kiskinis E. Traumatic injury causes selective degeneration and TDP-43 mislocalization in human iPSC-derived C9orf72-associated ALS/FTD motor neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.21.586073. [PMID: 38585915 PMCID: PMC10996466 DOI: 10.1101/2024.03.21.586073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
A hexanucleotide repeat expansion (HRE) in C9orf72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). However, patients with the HRE exhibit a wide disparity in clinical presentation and age of symptom onset suggesting an interplay between genetic background and environmental stressors. Neurotrauma as a result of traumatic brain or spinal cord injury has been shown to increase the risk of ALS/FTD in epidemiological studies. Here, we combine patient-specific induced pluripotent stem cells (iPSCs) with a custom-built device to deliver biofidelic stretch trauma to C9orf72 patient and isogenic control motor neurons (MNs) in vitro. We find that mutant but not control MNs exhibit selective degeneration after a single incident of severe trauma, which can be partially rescued by pretreatment with a C9orf72 antisense oligonucleotide. A single incident of mild trauma does not cause degeneration but leads to cytoplasmic accumulation of TDP-43 in C9orf72 MNs. This mislocalization, which only occurs briefly in isogenic controls, is eventually restored in C9orf72 MNs after 6 days. Lastly, repeated mild trauma ablates the ability of patient MNs to recover. These findings highlight alterations in TDP-43 dynamics in C9orf72 ALS/FTD patient MNs following traumatic injury and demonstrate that neurotrauma compounds neuropathology in C9orf72 ALS/FTD. More broadly, our work establishes an in vitro platform that can be used to interrogate the mechanistic interactions between ALS/FTD and neurotrauma.
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Affiliation(s)
- Eric J. Martin
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Citlally Santacruz
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Angela Mitevska
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Ian E. Jones
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Gopinath Krishnan
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Fen-Biao Gao
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - John D. Finan
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Evangelos Kiskinis
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Simpson Querrey Institute, Northwestern University, Chicago, Illinois 60611, USA
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
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5
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Gotoh S, Mori K, Fujino Y, Kawabe Y, Yamashita T, Omi T, Nagata K, Tagami S, Nagai Y, Ikeda M. eIF5 stimulates the CUG initiation of RAN translation of poly-GA dipeptide repeat protein (DPR) in C9orf72 FTLD/ALS. J Biol Chem 2024; 300:105703. [PMID: 38301895 PMCID: PMC10904283 DOI: 10.1016/j.jbc.2024.105703] [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: 10/18/2023] [Revised: 01/20/2024] [Accepted: 01/23/2024] [Indexed: 02/03/2024] Open
Abstract
Tandem GGGGCC repeat expansion in C9orf72 is a genetic cause of frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). Transcribed repeats are translated into dipeptide repeat proteins via repeat-associated non-AUG (RAN) translation. However, the regulatory mechanism of RAN translation remains unclear. Here, we reveal a GTPase-activating protein, eukaryotic initiation factor 5 (eIF5), which allosterically facilitates the conversion of eIF2-bound GTP into GDP upon start codon recognition, as a novel modifier of C9orf72 RAN translation. Compared to global translation, eIF5, but not its inactive mutants, preferentially stimulates poly-GA RAN translation. RAN translation is increased during integrated stress response, but the stimulatory effect of eIF5 on poly-GA RAN translation was additive to the increase of RAN translation during integrated stress response, with no further increase in phosphorylated eIF2α. Moreover, an alteration of the CUG near cognate codon to CCG or AUG in the poly-GA reading frame abolished the stimulatory effects, indicating that eIF5 primarily acts through the CUG-dependent initiation. Lastly, in a Drosophila model of C9orf72 FTLD/ALS that expresses GGGGCC repeats in the eye, knockdown of endogenous eIF5 by two independent RNAi strains significantly reduced poly-GA expressions, confirming in vivo effect of eIF5 on poly-GA RAN translation. Together, eIF5 stimulates the CUG initiation of poly-GA RAN translation in cellular and Drosophila disease models of C9orf72 FTLD/ALS.
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Affiliation(s)
- Shiho Gotoh
- Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Japan
| | - Kohji Mori
- Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Japan.
| | - Yuzo Fujino
- Department of Neurology, Kindai University Faculty of Medicine, Osaka-Sayama, Japan; Department of Neurology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yuya Kawabe
- Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Japan
| | - Tomoko Yamashita
- Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Japan
| | - Tsubasa Omi
- Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Japan
| | - Kenichi Nagata
- Department of Precision Medicine for Dementia, Osaka University Graduate School of Medicine, Suita, Japan
| | - Shinji Tagami
- Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yoshitaka Nagai
- Department of Neurology, Kindai University Faculty of Medicine, Osaka-Sayama, Japan
| | - Manabu Ikeda
- Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Japan
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6
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Grove DJ, Russell PJ, Kearse MG. To initiate or not to initiate: A critical assessment of eIF2A, eIF2D, and MCT-1·DENR to deliver initiator tRNA to ribosomes. WILEY INTERDISCIPLINARY REVIEWS. RNA 2024; 15:e1833. [PMID: 38433101 DOI: 10.1002/wrna.1833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/15/2024] [Accepted: 01/17/2024] [Indexed: 03/05/2024]
Abstract
Selection of the correct start codon is critical for high-fidelity protein synthesis. In eukaryotes, this is typically governed by a multitude of initiation factors (eIFs), including eIF2·GTP that directly delivers the initiator tRNA (Met-tRNAi Met ) to the P site of the ribosome. However, numerous reports, some dating back to the early 1970s, have described other initiation factors having high affinity for the initiator tRNA and the ability of delivering it to the ribosome, which has provided a foundation for further work demonstrating non-canonical initiation mechanisms using alternative initiation factors. Here we provide a critical analysis of current understanding of eIF2A, eIF2D, and the MCT-1·DENR dimer, the evidence surrounding their ability to initiate translation, their implications in human disease, and lay out important key questions for the field. This article is categorized under: RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes Translation > Mechanisms Translation > Regulation.
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Affiliation(s)
- Daisy J Grove
- The Ohio State Biochemistry Program, Department of Biological Chemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Paul J Russell
- The Ohio State Biochemistry Program, Department of Biological Chemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
- The Cellular, Molecular, Biochemical Sciences Program, Department of Biological Chemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Michael G Kearse
- The Ohio State Biochemistry Program, Department of Biological Chemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
- The Cellular, Molecular, Biochemical Sciences Program, Department of Biological Chemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
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7
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Albert-Gasco H, Smith HL, Alvarez-Castelao B, Swinden D, Halliday M, Janaki-Raman S, Butcher AJ, Mallucci GR. Trazodone rescues dysregulated synaptic and mitochondrial nascent proteomes in prion neurodegeneration. Brain 2024; 147:649-664. [PMID: 37703312 PMCID: PMC10834243 DOI: 10.1093/brain/awad313] [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: 06/02/2023] [Revised: 09/01/2023] [Accepted: 09/01/2023] [Indexed: 09/15/2023] Open
Abstract
The unfolded protein response (UPR) is rapidly gaining momentum as a therapeutic target for protein misfolding neurodegenerative diseases, in which its overactivation results in sustained translational repression leading to synapse loss and neurodegeneration. In mouse models of these disorders, from Alzheimer's to prion disease, modulation of the pathway-including by the licensed drug, trazodone-restores global protein synthesis rates with profound neuroprotective effects. However, the precise nature of the translational impairment, in particular the specific proteins affected in disease, and their response to therapeutic UPR modulation are poorly understood. We used non-canonical amino acid tagging (NCAT) to measure de novo protein synthesis in the brains of prion-diseased mice with and without trazodone treatment, in both whole hippocampus and cell-specifically. During disease the predominant nascent proteome changes occur in synaptic, cytoskeletal and mitochondrial proteins in both hippocampal neurons and astrocytes. Remarkably, trazodone treatment for just 2 weeks largely restored the whole disease nascent proteome in the hippocampus to that of healthy, uninfected mice, predominantly with recovery of proteins involved in synaptic and mitochondrial function. In parallel, trazodone treatment restored the disease-associated decline in synapses and mitochondria and their function to wild-type levels. In conclusion, this study increases our understanding of how translational repression contributes to neurodegeneration through synaptic and mitochondrial toxicity via depletion of key proteins essential for their function. Further, it provides new insights into the neuroprotective mechanisms of trazodone through reversal of this toxicity, relevant for the treatment of neurodegenerative diseases via translational modulation.
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Affiliation(s)
- Hector Albert-Gasco
- UK Dementia Research Institute and Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK
- Cambridge Institute of Science, Altos Labs, Great Abington CB21 6GP, UK
| | - Heather L Smith
- UK Dementia Research Institute and Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK
- Cambridge Institute of Science, Altos Labs, Great Abington CB21 6GP, UK
| | - Beatriz Alvarez-Castelao
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, 28040 Madrid, Spain
- The San Carlos Hospital Health Research Institute, IdISSC, 28040 Madrid, Spain
| | - Dean Swinden
- UK Dementia Research Institute and Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK
- Cambridge Institute of Science, Altos Labs, Great Abington CB21 6GP, UK
| | - Mark Halliday
- Cambridge Institute of Science, Altos Labs, Great Abington CB21 6GP, UK
| | | | - Adrian J Butcher
- UK Dementia Research Institute and Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK
- Cambridge Institute of Science, Altos Labs, Great Abington CB21 6GP, UK
| | - Giovanna R Mallucci
- UK Dementia Research Institute and Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK
- Cambridge Institute of Science, Altos Labs, Great Abington CB21 6GP, UK
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8
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Smeele PH, Cesare G, Vaccari T. ALS' Perfect Storm: C9orf72-Associated Toxic Dipeptide Repeats as Potential Multipotent Disruptors of Protein Homeostasis. Cells 2024; 13:178. [PMID: 38247869 PMCID: PMC10813877 DOI: 10.3390/cells13020178] [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: 12/13/2023] [Revised: 01/10/2024] [Accepted: 01/12/2024] [Indexed: 01/23/2024] Open
Abstract
Protein homeostasis is essential for neuron longevity, requiring a balanced regulation between protein synthesis and degradation. The clearance of misfolded and aggregated proteins, mediated by autophagy and the ubiquitin-proteasome systems, maintains protein homeostasis in neurons, which are post-mitotic and thus cannot use cell division to diminish the burden of misfolded proteins. When protein clearance pathways are overwhelmed or otherwise disrupted, the accumulation of misfolded or aggregated proteins can lead to the activation of ER stress and the formation of stress granules, which predominantly attempt to restore the homeostasis by suppressing global protein translation. Alterations in these processes have been widely reported among studies investigating the toxic function of dipeptide repeats (DPRs) produced by G4C2 expansion in the C9orf72 gene of patients with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). In this review, we outline the modalities of DPR-induced disruptions in protein homeostasis observed in a wide range of models of C9orf72-linked ALS/FTD. We also discuss the relative importance of each DPR for toxicity, possible synergies between DPRs, and discuss the possible functional relevance of DPR aggregation to disease pathogenesis. Finally, we highlight the interdependencies of the observed effects and reflect on the importance of feedback and feedforward mechanisms in their contribution to disease progression. A better understanding of DPR-associated disease pathogenesis discussed in this review might shed light on disease vulnerabilities that may be amenable with therapeutic interventions.
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Affiliation(s)
| | | | - Thomas Vaccari
- Department of Biosciences, University of Milan, Via Celoria 26, 20133 Milan, Italy
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Harley P, Kerins C, Gatt A, Neves G, Riccio F, Machado CB, Cheesbrough A, R'Bibo L, Burrone J, Lieberam I. Aberrant axon initial segment plasticity and intrinsic excitability of ALS hiPSC motor neurons. Cell Rep 2023; 42:113509. [PMID: 38019651 DOI: 10.1016/j.celrep.2023.113509] [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: 05/04/2023] [Revised: 10/06/2023] [Accepted: 11/13/2023] [Indexed: 12/01/2023] Open
Abstract
Dysregulated neuronal excitability is a hallmark of amyotrophic lateral sclerosis (ALS). We sought to investigate how functional changes to the axon initial segment (AIS), the site of action potential generation, could impact neuronal excitability in ALS human induced pluripotent stem cell (hiPSC) motor neurons. We find that early TDP-43 and C9orf72 hiPSC motor neurons show an increase in the length of the AIS and impaired activity-dependent AIS plasticity that is linked to abnormal homeostatic regulation of neuronal activity and intrinsic hyperexcitability. In turn, these hyperactive neurons drive increased spontaneous myofiber contractions of in vitro hiPSC motor units. In contrast, late hiPSC and postmortem ALS motor neurons show AIS shortening, and hiPSC motor neurons progress to hypoexcitability. At a molecular level, aberrant expression of the AIS master scaffolding protein ankyrin-G and AIS-specific voltage-gated sodium channels mirror these dynamic changes in AIS function and excitability. Our results point toward the AIS as an important site of dysfunction in ALS motor neurons.
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Affiliation(s)
- Peter Harley
- Centre for Gene Therapy & Regenerative Medicine, Kings College London, London SE1 9RT, UK; Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK; UCL Queen Square Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Caoimhe Kerins
- Centre for Gene Therapy & Regenerative Medicine, Kings College London, London SE1 9RT, UK; Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK; Centre for Craniofacial & Regenerative Biology, King's College London, London SE1 9RT, UK
| | - Ariana Gatt
- Queen Square Brain Bank, Department of Neurodegenerative Disease, Institute of Neurology, University College London, London WC1N 1PJ, UK
| | - Guilherme Neves
- Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK
| | - Federica Riccio
- Centre for Gene Therapy & Regenerative Medicine, Kings College London, London SE1 9RT, UK; Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK
| | - Carolina Barcellos Machado
- Centre for Gene Therapy & Regenerative Medicine, Kings College London, London SE1 9RT, UK; Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK
| | - Aimee Cheesbrough
- Centre for Gene Therapy & Regenerative Medicine, Kings College London, London SE1 9RT, UK; Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK
| | - Lea R'Bibo
- Centre for Gene Therapy & Regenerative Medicine, Kings College London, London SE1 9RT, UK; Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK
| | - Juan Burrone
- Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK; MRC Centre for Neurodevelopmental Disorders, Kings College London, London SE1 1UL, UK.
| | - Ivo Lieberam
- Centre for Gene Therapy & Regenerative Medicine, Kings College London, London SE1 9RT, UK; Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK; MRC Centre for Neurodevelopmental Disorders, Kings College London, London SE1 1UL, UK.
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10
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Glineburg MR, Yildirim E, Gomez N, Li X, Pak J, Altheim C, Waksmacki J, McInerney G, Barmada SJ, Todd PK. Stress granule formation helps to mitigate neurodegeneration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.07.566060. [PMID: 37986813 PMCID: PMC10659376 DOI: 10.1101/2023.11.07.566060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Cellular stress pathways that inhibit translation initiation lead to transient formation of cytoplasmic RNA/protein complexes known as stress granules. Many of the proteins found within stress granules and the dynamics of stress granule formation and dissolution are implicated in neurodegenerative disease. Whether stress granule formation is protective or harmful in neurodegenerative conditions is not known. To address this, we took advantage of the alphavirus protein nsP3, which selectively binds dimers of the central stress granule nucleator protein G3BP ( rin in Drosophila ) and markedly reduces stress granule formation without directly impacting the protein translational inhibitory pathways that trigger stress granule formation. In Drosophila and rodent neurons, reducing stress granule formation with nsP3 had modest impacts on lifespan even in the setting of serial stress pathway induction. In contrast, reducing stress granule formation in models of ataxia, amyotrophic lateral sclerosis and frontotemporal dementia largely exacerbated disease phenotypes. These data support a model whereby stress granules mitigate, rather than promote, neurodegenerative cascades.
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11
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Ortega JA, Sasselli IR, Boccitto M, Fleming AC, Fortuna TR, Li Y, Sato K, Clemons TD, Mckenna ED, Nguyen TP, Anderson EN, Asin J, Ichida JK, Pandey UB, Wolin SL, Stupp SI, Kiskinis E. CLIP-Seq analysis enables the design of protective ribosomal RNA bait oligonucleotides against C9ORF72 ALS/FTD poly-GR pathophysiology. SCIENCE ADVANCES 2023; 9:eadf7997. [PMID: 37948524 PMCID: PMC10637751 DOI: 10.1126/sciadv.adf7997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 10/11/2023] [Indexed: 11/12/2023]
Abstract
Amyotrophic lateral sclerosis and frontotemporal dementia patients with a hexanucleotide repeat expansion in C9ORF72 (C9-HRE) accumulate poly-GR and poly-PR aggregates. The pathogenicity of these arginine-rich dipeptide repeats (R-DPRs) is thought to be driven by their propensity to bind low-complexity domains of multivalent proteins. However, the ability of R-DPRs to bind native RNA and the significance of this interaction remain unclear. Here, we used computational and experimental approaches to characterize the physicochemical properties of R-DPRs and their interaction with RNA. We find that poly-GR predominantly binds ribosomal RNA (rRNA) in cells and exhibits an interaction that is predicted to be energetically stronger than that for associated ribosomal proteins. Critically, modified rRNA "bait" oligonucleotides restore poly-GR-associated ribosomal deficits and ameliorate poly-GR toxicity in patient neurons and Drosophila models. Our work strengthens the hypothesis that ribosomal function is impaired by R-DPRs, highlights a role for direct rRNA binding in mediating ribosomal dysfunction, and presents a strategy for protecting against C9-HRE pathophysiological mechanisms.
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Affiliation(s)
- Juan A. Ortega
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Department of Pathology and Experimental Therapy, Institute of Neurosciences, University of Barcelona, Barcelona 08907, Spain
| | - Ivan R. Sasselli
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL 60611, USA
- Center for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA), Donostia-San Sebastián 20014, Spain
- Centro de Fisica de Materiales (CFM), CSIC-UPV/EHU, 20018 San Sebastián, Spain
| | - Marco Boccitto
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Andrew C. Fleming
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Tyler R. Fortuna
- Department of Pediatrics, Children’s Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, USA
| | - Yichen Li
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Kohei Sato
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL 60611, USA
| | - Tristan D. Clemons
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL 60611, USA
| | - Elizabeth D. Mckenna
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Thao P. Nguyen
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Eric N. Anderson
- Department of Pediatrics, Children’s Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, USA
| | - Jesus Asin
- Department of Statistical Methods, School of Engineering, University of Zaragoza, Zaragoza 50018, Spain
| | - Justin K. Ichida
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Udai B. Pandey
- Department of Pediatrics, Children’s Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, USA
| | - Sandra L. Wolin
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Samuel I. Stupp
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL 60611, USA
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Evangelos Kiskinis
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL 60611, USA
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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12
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Grove DJ, Levine DJ, Kearse MG. Increased levels of eIF2A inhibit translation by sequestering 40S ribosomal subunits. Nucleic Acids Res 2023; 51:9983-10000. [PMID: 37602404 PMCID: PMC10570035 DOI: 10.1093/nar/gkad683] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 08/03/2023] [Accepted: 08/09/2023] [Indexed: 08/22/2023] Open
Abstract
eIF2A was the first eukaryotic initiator tRNA carrier discovered but its exact function has remained enigmatic. Uncharacteristic of translation initiation factors, eIF2A is reported to be non-cytosolic in multiple human cancer cell lines. Attempts to study eIF2A mechanistically have been limited by the inability to achieve high yield of soluble recombinant protein. Here, we developed a purification paradigm that yields ∼360-fold and ∼6000-fold more recombinant human eIF2A from Escherichia coli and insect cells, respectively, than previous reports. Using a mammalian in vitro translation system, we found that increased levels of recombinant human eIF2A inhibit translation of multiple reporter mRNAs, including those that are translated by cognate and near-cognate start codons, and does so prior to start codon recognition. eIF2A also inhibited translation directed by all four types of cap-independent viral IRESs, including the CrPV IGR IRES that does not require initiation factors or initiator tRNA, suggesting excess eIF2A sequesters 40S subunits. Supplementation with additional 40S subunits prevented eIF2A-mediated inhibition and pull-down assays demonstrated direct binding between recombinant eIF2A and purified 40S subunits. These data support a model that eIF2A must be kept away from the translation machinery to avoid sequestering 40S ribosomal subunits.
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Affiliation(s)
- Daisy J Grove
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
- Department of Biological Chemistry and Pharmacology, Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Daniel J Levine
- Department of Biological Chemistry and Pharmacology, Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Michael G Kearse
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
- Department of Biological Chemistry and Pharmacology, Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
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13
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Beckers J, Tharkeshwar AK, Fumagalli L, Contardo M, Van Schoor E, Fazal R, Thal DR, Chandran S, Mancuso R, Van Den Bosch L, Van Damme P. A toxic gain-of-function mechanism in C9orf72 ALS impairs the autophagy-lysosome pathway in neurons. Acta Neuropathol Commun 2023; 11:151. [PMID: 37723585 PMCID: PMC10506245 DOI: 10.1186/s40478-023-01648-0] [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: 08/28/2023] [Accepted: 08/30/2023] [Indexed: 09/20/2023] Open
Abstract
BACKGROUND Motor neurons (MNs), which are primarily affected in amyotrophic lateral sclerosis (ALS), are a specialized type of neurons that are long and non-dividing. Given their unique structure, these cells heavily rely on transport of organelles along their axons and the process of autophagy to maintain their cellular homeostasis. It has been shown that disruption of the autophagy pathway is sufficient to cause progressive neurodegeneration and defects in autophagy have been associated with various subtypes of ALS, including those caused by hexanucleotide repeat expansions in the C9orf72 gene. A more comprehensive understanding of the dysfunctional cellular mechanisms will help rationalize the design of potent and selective therapies for C9orf72-ALS. METHODS In this study, we used induced pluripotent stem cell (iPSC)-derived MNs from C9orf72-ALS patients and isogenic control lines to identify the underlying mechanisms causing dysregulations of the autophagy-lysosome pathway. Additionally, to ascertain the potential impact of C9orf72 loss-of-function on autophagic defects, we characterized the observed phenotypes in a C9orf72 knockout iPSC line (C9-KO). RESULTS Despite the evident presence of dysfunctions in several aspects of the autophagy-lysosome pathway, such as disrupted lysosomal homeostasis, abnormal lysosome morphology, inhibition of autophagic flux, and accumulation of p62 in C9orf72-ALS MNs, we were surprised to find that C9orf72 loss-of-function had minimal influence on these phenotypes. Instead, we primarily observed impairment in endosome maturation as a result of C9orf72 loss-of-function. Additionally, our study shed light on the pathological mechanisms underlying C9orf72-ALS, as we detected an increased TBK1 phosphorylation at S172 in MNs derived from C9orf72 ALS patients. CONCLUSIONS Our data provides further insight into the involvement of defects in the autophagy-lysosome pathway in C9orf72-ALS and strongly indicate that those defects are mainly due to the toxic gain-of-function mechanisms underlying C9orf72-ALS.
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Affiliation(s)
- Jimmy Beckers
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Louvain - University of Leuven, Leuven, Belgium.
- Center for Brain and Disease Research, Laboratory of Neurobiology, VIB, Leuven, Belgium.
| | - Arun Kumar Tharkeshwar
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Louvain - University of Leuven, Leuven, Belgium
- Center for Brain and Disease Research, Laboratory of Neurobiology, VIB, Leuven, Belgium
- Department of Human Genetics, KU Leuven, Louvain, Belgium
| | - Laura Fumagalli
- Center for Molecular Neurology, Microglia and Inflammation in Neurological Disorders (MIND) Lab, VIB, Antwerp, Belgium
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Matilde Contardo
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Louvain - University of Leuven, Leuven, Belgium
- Center for Brain and Disease Research, Laboratory of Neurobiology, VIB, Leuven, Belgium
| | - Evelien Van Schoor
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Louvain - University of Leuven, Leuven, Belgium
- Center for Brain and Disease Research, Laboratory of Neurobiology, VIB, Leuven, Belgium
- Laboratory of Neuropathology, Department of Imaging and Pathology, Leuven Brain Institute (LBI), KU Louvain - University of Leuven, Leuven, Belgium
| | - Raheem Fazal
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Louvain - University of Leuven, Leuven, Belgium
- Center for Brain and Disease Research, Laboratory of Neurobiology, VIB, Leuven, Belgium
| | - Dietmar Rudolf Thal
- Laboratory of Neuropathology, Department of Imaging and Pathology, Leuven Brain Institute (LBI), KU Louvain - University of Leuven, Leuven, Belgium
- Department of Pathology, University Hospitals Leuven, Louvain, Belgium
| | - Siddharthan Chandran
- UK Dementia Research Institute, University of Edinburgh, Edinburgh, EH16 4SB, UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Renzo Mancuso
- Center for Molecular Neurology, Microglia and Inflammation in Neurological Disorders (MIND) Lab, VIB, Antwerp, Belgium
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Ludo Van Den Bosch
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Louvain - University of Leuven, Leuven, Belgium
- Center for Brain and Disease Research, Laboratory of Neurobiology, VIB, Leuven, Belgium
| | - Philip Van Damme
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Louvain - University of Leuven, Leuven, Belgium.
- Center for Brain and Disease Research, Laboratory of Neurobiology, VIB, Leuven, Belgium.
- Department of Neurology, University Hospitals Leuven, Louvain, Belgium.
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14
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Latallo MJ, Wang S, Dong D, Nelson B, Livingston NM, Wu R, Zhao N, Stasevich TJ, Bassik MC, Sun S, Wu B. Single-molecule imaging reveals distinct elongation and frameshifting dynamics between frames of expanded RNA repeats in C9ORF72-ALS/FTD. Nat Commun 2023; 14:5581. [PMID: 37696852 PMCID: PMC10495369 DOI: 10.1038/s41467-023-41339-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 08/30/2023] [Indexed: 09/13/2023] Open
Abstract
C9ORF72 hexanucleotide repeat expansion is the most common genetic cause of both amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). One pathogenic mechanism is the accumulation of toxic dipeptide repeat (DPR) proteins like poly-GA, GP and GR, produced by the noncanonical translation of the expanded RNA repeats. However, how different DPRs are synthesized remains elusive. Here, we use single-molecule imaging techniques to directly measure the translation dynamics of different DPRs. Besides initiation, translation elongation rates vary drastically between different frames, with GP slower than GA and GR the slowest. We directly visualize frameshift events using a two-color single-molecule translation assay. The repeat expansion enhances frameshifting, but the overall frequency is low. There is a higher chance of GR-to-GA shift than in the reversed direction. Finally, the ribosome-associated protein quality control (RQC) factors ZNF598 and Pelota modulate the translation dynamics, and the repeat RNA sequence is important for invoking the RQC pathway. This study reveals that multiple translation steps modulate the final DPR production. Understanding repeat RNA translation is critically important to decipher the DPR-mediated pathogenesis and identify potential therapeutic targets in C9ORF72-ALS/FTD.
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Affiliation(s)
- Malgorzata J Latallo
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Shaopeng Wang
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Daoyuan Dong
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Blake Nelson
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Nathan M Livingston
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Rong Wu
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Ning Zhao
- Department of Biochemistry and Molecular Genetics, University of Colorado-Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Timothy J Stasevich
- Department of Biochemistry and Molecular Genetics, University of Colorado-Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Michael C Bassik
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Shuying Sun
- Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Bin Wu
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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15
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Wang S, Sun S. Translation dysregulation in neurodegenerative diseases: a focus on ALS. Mol Neurodegener 2023; 18:58. [PMID: 37626421 PMCID: PMC10464328 DOI: 10.1186/s13024-023-00642-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 07/21/2023] [Indexed: 08/27/2023] Open
Abstract
RNA translation is tightly controlled in eukaryotic cells to regulate gene expression and maintain proteome homeostasis. RNA binding proteins, translation factors, and cell signaling pathways all modulate the translation process. Defective translation is involved in multiple neurological diseases including amyotrophic lateral sclerosis (ALS). ALS is a progressive neurodegenerative disorder and poses a major public health challenge worldwide. Over the past few years, tremendous advances have been made in the understanding of the genetics and pathogenesis of ALS. Dysfunction of RNA metabolisms, including RNA translation, has been closely associated with ALS. Here, we first introduce the general mechanisms of translational regulation under physiological and stress conditions and review well-known examples of translation defects in neurodegenerative diseases. We then focus on ALS-linked genes and discuss the recent progress on how translation is affected by various mutant genes and the repeat expansion-mediated non-canonical translation in ALS.
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Affiliation(s)
- Shaopeng Wang
- Department of Physiology and Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Shuying Sun
- Department of Physiology and Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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16
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Malik I, Tseng YJ, Wieland CM, Green KM, Zheng K, Calleja K, Todd PK. Dissecting the roles of EIF4G homologs reveals DAP5 as a modifier of CGG repeat-associated toxicity in a Drosophila model of FXTAS. Neurobiol Dis 2023; 184:106212. [PMID: 37352983 PMCID: PMC11149892 DOI: 10.1016/j.nbd.2023.106212] [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: 04/16/2023] [Revised: 06/19/2023] [Accepted: 06/21/2023] [Indexed: 06/25/2023] Open
Abstract
Neurodegeneration in Fragile X-associated tremor/ataxia syndrome (FXTAS) is caused by a CGG trinucleotide repeat expansion in the 5' UTR of FMR1. Expanded CGG repeat RNAs form stable secondary structures, which in turn support repeat-associated non-AUG (RAN) translation to produce toxic peptides. The parameters that impact RAN translation initiation efficiency are not well understood. Here we used a Drosophila melanogaster model of FXTAS to evaluate the role of the eIF4G family of eukaryotic translation initiation factors (EIF4G1, EIF4GII and EIF4G2/DAP5) in modulating RAN translation and CGG repeat-associated toxicity. DAP5 knockdown robustly suppressed CGG repeat-associated toxicity and inhibited RAN translation. Furthermore, knockdown of initiation factors that preferentially associate with DAP5 (such as EIF2β, EIF3F and EIF3G) also selectively suppressed CGG repeat-induced eye degeneration. In mammalian cellular reporter assays, DAP5 knockdown exhibited modest and cell-type specific effects on RAN translation. Taken together, these data support a role for DAP5 in CGG repeat associated toxicity possibly through modulation of RAN translation.
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Affiliation(s)
- Indranil Malik
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Yi-Ju Tseng
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA; Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Clare M Wieland
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Katelyn M Green
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Kristina Zheng
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Katyanne Calleja
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA; Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI, USA.
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17
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Ghaffari LT, Trotti D, Haeusler AR. Differential response of C9orf72 transcripts following neuronal depolarization. iScience 2023; 26:106959. [PMID: 37332610 PMCID: PMC10272498 DOI: 10.1016/j.isci.2023.106959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 04/19/2023] [Accepted: 05/22/2023] [Indexed: 06/20/2023] Open
Abstract
The (G4C2)n nucleotide repeat expansion (NRE) mutation in C9orf72 is the most common genetic cause of ALS and FTD. The biological functions of C9orf72 are becoming understood, but it is unclear if this gene is regulated in a neural-specific manner. Neuronal activity is a crucial modifier of biological processes in health and neurodegenerative disease contexts. Here, we show that prolonged membrane depolarization in healthy human iPSC-cortical neurons leads to a significant downregulation of a transcript variant 3 (V3) of C9orf72, with a concomitant increase in variant 2 (V2), which leads to total C9orf72 RNA transcript levels remaining unchanged. However, the same response is not observed in cortical neurons derived from patients with the C9-NRE mutation. These findings reveal the impact of depolarization on C9orf72 transcripts, and how this response diverges in C9-NRE-carriers, which may have important implications in the underlying unique clinical associations of C9-NRE transcripts and disease pathogenesis.
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Affiliation(s)
- Layla T. Ghaffari
- Jefferson Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Davide Trotti
- Jefferson Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Aaron R. Haeusler
- Jefferson Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
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18
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Nelson AT, Cicardi ME, Markandaiah SS, Han J, Philp N, Welebob E, Haeusler AR, Pasinelli P, Manfredi G, Kawamata H, Trotti D. Glucose Hypometabolism Prompts RAN Translation and Exacerbates C9orf72-related ALS/FTD Phenotypes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.07.544100. [PMID: 37333144 PMCID: PMC10274806 DOI: 10.1101/2023.06.07.544100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
The most prevalent genetic cause of both amyotrophic lateral sclerosis and frontotemporal dementia is a (GGGGCC)n nucleotide repeat expansion (NRE) occurring in the first intron of the C9orf72 gene (C9). Brain glucose hypometabolism is consistently observed in C9-NRE carriers, even at pre-symptomatic stages, although its potential role in disease pathogenesis is unknown. Here, we identified alterations in glucose metabolic pathways and ATP levels in the brain of asymptomatic C9-BAC mice. We found that, through activation of the GCN2 kinase, glucose hypometabolism drives the production of dipeptide repeat proteins (DPRs), impairs the survival of C9 patient-derived neurons, and triggers motor dysfunction in C9-BAC mice. We also found that one of the arginine-rich DPRs (PR) can directly contribute to glucose metabolism and metabolic stress. These findings provide a mechanistic link between energy imbalances and C9-ALS/FTD pathogenesis and support a feedforward loop model that opens several opportunities for therapeutic intervention.
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Affiliation(s)
- A T Nelson
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - M E Cicardi
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - S S Markandaiah
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - J Han
- Department of Pathology and Genomic Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - N Philp
- Department of Pathology and Genomic Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - E Welebob
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - A R Haeusler
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - P Pasinelli
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - G Manfredi
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, 407 East 61st Street, New York, New York 10065, USA
| | - H Kawamata
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, 407 East 61st Street, New York, New York 10065, USA
| | - D Trotti
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
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19
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Tzeplaeff L, Wilfling S, Requardt MV, Herdick M. Current State and Future Directions in the Therapy of ALS. Cells 2023; 12:1523. [PMID: 37296644 PMCID: PMC10252394 DOI: 10.3390/cells12111523] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/19/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disorder affecting upper and lower motor neurons, with death resulting mainly from respiratory failure three to five years after symptom onset. As the exact underlying causative pathological pathway is unclear and potentially diverse, finding a suitable therapy to slow down or possibly stop disease progression remains challenging. Varying by country Riluzole, Edaravone, and Sodium phenylbutyrate/Taurursodiol are the only drugs currently approved in ALS treatment for their moderate effect on disease progression. Even though curative treatment options, able to prevent or stop disease progression, are still unknown, recent breakthroughs, especially in the field of targeting genetic disease forms, raise hope for improved care and therapy for ALS patients. In this review, we aim to summarize the current state of ALS therapy, including medication as well as supportive therapy, and discuss the ongoing developments and prospects in the field. Furthermore, we highlight the rationale behind the intense research on biomarkers and genetic testing as a feasible way to improve the classification of ALS patients towards personalized medicine.
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Affiliation(s)
- Laura Tzeplaeff
- Department of Neurology, Rechts der Isar Hospital, Technical University of Munich, 81675 München, Germany
| | - Sibylle Wilfling
- Department of Neurology, University of Regensburg, 93053 Regensburg, Germany;
- Center for Human Genetics Regensburg, 93059 Regensburg, Germany
| | - Maria Viktoria Requardt
- Formerly: Department of Neurology with Institute of Translational Neurology, Münster University Hospital (UKM), 48149 Münster, Germany;
| | - Meret Herdick
- Precision Neurology, University of Lübeck, 23562 Luebeck, Germany
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20
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Du H, Huo Z, Chen Y, Zhao Z, Meng F, Wang X, Liu S, Zhang H, Zhou F, Liu J, Zhang L, Zhou S, Guan Y, Wang X. Induced Pluripotent Stem Cells and Their Applications in Amyotrophic Lateral Sclerosis. Cells 2023; 12:cells12060971. [PMID: 36980310 PMCID: PMC10047679 DOI: 10.3390/cells12060971] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/20/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that results in the loss of motor function in the central nervous system (CNS) and ultimately death. The mechanisms underlying ALS pathogenesis have not yet been fully elucidated, and ALS cannot be treated effectively. Most studies have applied animal or single-gene intervention cell lines as ALS disease models, but they cannot accurately reflect the pathological characteristics of ALS. Induced pluripotent stem cells (iPSCs) can be reprogrammed from somatic cells, possessing the ability to self-renew and differentiate into a variety of cells. iPSCs can be obtained from ALS patients with different genotypes and phenotypes, and the genetic background of the donor cells remains unchanged during reprogramming. iPSCs can differentiate into neurons and glial cells related to ALS. Therefore, iPSCs provide an excellent method to evaluate the impact of diseases on ALS patients. Moreover, patient-derived iPSCs are obtained from their own somatic cells, avoiding ethical concerns and posing only a low risk of immune rejection. The iPSC technology creates new hope for ALS treatment. Here, we review recent studies on iPSCs and their applications in disease modeling, drug screening and cell therapy in ALS, with a particular focus on the potential for ALS treatment.
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Affiliation(s)
- Hongmei Du
- Department of Histology and Embryology, School of Basic Medical Sciences, Weifang Medical University, Weifang 261053, China
- Neurologic Disorders and Regenerative Repair Laboratory, Weifang Medical University, Weifang 261053, China
| | - Zijun Huo
- Department of Histology and Embryology, School of Basic Medical Sciences, Weifang Medical University, Weifang 261053, China
| | - Yanchun Chen
- Department of Histology and Embryology, School of Basic Medical Sciences, Weifang Medical University, Weifang 261053, China
- Neurologic Disorders and Regenerative Repair Laboratory, Weifang Medical University, Weifang 261053, China
| | - Zhenhan Zhao
- Department of Histology and Embryology, School of Basic Medical Sciences, Weifang Medical University, Weifang 261053, China
| | - Fandi Meng
- Department of Histology and Embryology, School of Basic Medical Sciences, Weifang Medical University, Weifang 261053, China
| | - Xuemei Wang
- Department of Histology and Embryology, School of Basic Medical Sciences, Weifang Medical University, Weifang 261053, China
| | - Shiyue Liu
- Neurologic Disorders and Regenerative Repair Laboratory, Weifang Medical University, Weifang 261053, China
| | - Haoyun Zhang
- Neurologic Disorders and Regenerative Repair Laboratory, Weifang Medical University, Weifang 261053, China
| | - Fenghua Zhou
- Neurologic Disorders and Regenerative Repair Laboratory, Weifang Medical University, Weifang 261053, China
- Department of Pathology, School of Basic Medical Sciences, Weifang Medical University, Weifang 261053, China
| | - Jinmeng Liu
- Neurologic Disorders and Regenerative Repair Laboratory, Weifang Medical University, Weifang 261053, China
| | - Lingyun Zhang
- Neurologic Disorders and Regenerative Repair Laboratory, Weifang Medical University, Weifang 261053, China
| | - Shuanhu Zhou
- Harvard Medical School and Harvard Stem Cell Institute, Harvard University, Boston, MA 02115, USA
| | - Yingjun Guan
- Department of Histology and Embryology, School of Basic Medical Sciences, Weifang Medical University, Weifang 261053, China
- Neurologic Disorders and Regenerative Repair Laboratory, Weifang Medical University, Weifang 261053, China
| | - Xin Wang
- Harvard Medical School and Harvard Stem Cell Institute, Harvard University, Boston, MA 02115, USA
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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21
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Storkebaum E, Rosenblum K, Sonenberg N. Messenger RNA Translation Defects in Neurodegenerative Diseases. N Engl J Med 2023; 388:1015-1030. [PMID: 36920757 DOI: 10.1056/nejmra2215795] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Affiliation(s)
- Erik Storkebaum
- From the Molecular Neurobiology Laboratory, Donders Center for Neuroscience, Donders Institute for Brain, Cognition, and Behavior, and the Faculty of Science, Radboud University, Nijmegen, the Netherlands (E.S.); the Sagol Department of Neurobiology, Faculty of Natural Sciences, and the Center for Genetic Manipulation in the Brain, University of Haifa, Haifa, Israel (K.R.); and the Department of Biochemistry and Goodman Cancer Institute, McGill University, Montreal (N.S.)
| | - Kobi Rosenblum
- From the Molecular Neurobiology Laboratory, Donders Center for Neuroscience, Donders Institute for Brain, Cognition, and Behavior, and the Faculty of Science, Radboud University, Nijmegen, the Netherlands (E.S.); the Sagol Department of Neurobiology, Faculty of Natural Sciences, and the Center for Genetic Manipulation in the Brain, University of Haifa, Haifa, Israel (K.R.); and the Department of Biochemistry and Goodman Cancer Institute, McGill University, Montreal (N.S.)
| | - Nahum Sonenberg
- From the Molecular Neurobiology Laboratory, Donders Center for Neuroscience, Donders Institute for Brain, Cognition, and Behavior, and the Faculty of Science, Radboud University, Nijmegen, the Netherlands (E.S.); the Sagol Department of Neurobiology, Faculty of Natural Sciences, and the Center for Genetic Manipulation in the Brain, University of Haifa, Haifa, Israel (K.R.); and the Department of Biochemistry and Goodman Cancer Institute, McGill University, Montreal (N.S.)
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22
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Martinez-Gonzalez L, Martinez A. Emerging clinical investigational drugs for the treatment of amyotrophic lateral sclerosis. Expert Opin Investig Drugs 2023; 32:141-160. [PMID: 36762798 DOI: 10.1080/13543784.2023.2178416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
INTRODUCTION Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder caused by motoneuron death with a median survival time of 3-5 years since disease onset. There are no effective treatments to date. However, a variety of innovative investigational drugs and biological-based therapies are under clinical development. AREAS COVERED This review provides an overview of the clinical investigational small molecules as well as a brief summary of the biological-based therapies that are currently undergoing clinical trials for the treatment of ALS. All the data were obtained from ClinicalTrials.gov (registered through November 1). EXPERT OPINION Drug discovery for ALS is an active and evolving field, where many investigational clinical drugs are in different trials. There are several mechanisms of action supporting all these new therapies, although proteostasis is gaining stage. Probably, small orally bioavailable molecules able to recover functional TDP-43 homeostasis may have solid chances to modify ALS progression.
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Affiliation(s)
- Loreto Martinez-Gonzalez
- Centro de Investigaciones Biológicas "Margarita Salas"-CSIC, Madrid, Spain.,Centro de Investigación Biomédica en Red en enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Ana Martinez
- Centro de Investigaciones Biológicas "Margarita Salas"-CSIC, Madrid, Spain.,Centro de Investigación Biomédica en Red en enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
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23
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Jiang J, Wang Y, Deng M. New developments and opportunities in drugs being trialed for amyotrophic lateral sclerosis from 2020 to 2022. Front Pharmacol 2022; 13:1054006. [PMID: 36518658 PMCID: PMC9742490 DOI: 10.3389/fphar.2022.1054006] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 11/14/2022] [Indexed: 08/31/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder that primarily affects motor neurons in the brain and spinal cord. In the recent past, there have been just two drugs approved for treatment, riluzole and edaravone, which only prolong survival by a few months. However, there are many novel experimental drugs in development. In this review, we summarize 53 new drugs that have been evaluated in clinical trials from 2020 to 2022, which we have classified into eight mechanistic groups (anti-apoptotic, anti-inflammatory, anti-excitotoxicity, regulated integrated stress response, neurotrophic factors and neuroprotection, anti-aggregation, gene therapy and other). Six were tested in phase 1 studies, 31 were in phase 2 studies, three failed in phase 3 studies and stopped further development, and the remaining 13 drugs were being tested in phase 3 studies, including methylcobalamin, masitinib, MN-166, verdiperstat, memantine, AMX0035, trazodone, CNM-Au8, pridopidine, SLS-005, IONN363, tofersen, and reldesemtiv. Among them, five drugs, including methylcobalamin, masitinib, AMX0035, CNM-Au8, and tofersen, have shown potent therapeutic effects in clinical trials. Recently, AMX0035 has been the third medicine approved by the FDA for the treatment of ALS after riluzole and edaravone.
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Affiliation(s)
| | | | - Min Deng
- Institute of Medical Innovation and Research, Peking University Third Hospital, Beijing, China
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24
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Ghaffari LT, Trotti D, Haeusler AR, Jensen BK. Breakdown of the central synapses in C9orf72-linked ALS/FTD. Front Mol Neurosci 2022; 15:1005112. [PMID: 36187344 PMCID: PMC9523884 DOI: 10.3389/fnmol.2022.1005112] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 08/29/2022] [Indexed: 01/07/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive, fatal neurodegenerative disease that leads to the death of motor and cortical neurons. The clinical manifestations of ALS are heterogenous, and efficacious treatments to significantly slow the progression of the disease are lacking. Cortical hyper-excitability is observed pre-symptomatically across disease-causative genetic variants, as well as in the early stages of sporadic ALS, and typically precedes motor neuron involvement and overt neurodegeneration. The causes of cortical hyper-excitability are not yet fully understood but is mainly agreed to be an early event. The identification of the nucleotide repeat expansion (GGGGCC)n in the C9ORF72 gene has provided evidence that ALS and another neurodegenerative disease, frontotemporal dementia (FTD), are part of a disease spectrum with common genetic origins. ALS and FTD are diseases in which synaptic dysfunction is reported throughout disease onset and stages of progression. It has become apparent that ALS/FTD-causative genes, such as C9ORF72, may have roles in maintaining the normal physiology of the synapse, as mutations in these genes often manifest in synaptic dysfunction. Here we review the dysfunctions of the central nervous system synapses associated with the nucleotide repeat expansion in C9ORF72 observed in patients, organismal, and cellular models of ALS and FTD.
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25
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Green KM, Miller SL, Malik I, Todd PK. Non-canonical initiation factors modulate repeat-associated non-AUG translation. Hum Mol Genet 2022; 31:2521-2534. [PMID: 35220421 PMCID: PMC9618161 DOI: 10.1093/hmg/ddac021] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 12/28/2021] [Accepted: 01/14/2022] [Indexed: 11/14/2022] Open
Abstract
Repeat-associated non-AUG (RAN) translation of expanded repeat-mutation mRNA produces toxic peptides in neurons of patients suffering from neurodegenerative diseases. Recent findings indicate that RAN translation in diverse model systems is not inhibited by cellular stressors that impair global translation through phosphorylation of the alpha subunit of eIF2, the essential eukaryotic translation initiation factor that brings the initiator tRNA to the 40S ribosome. Using in vitro, cell-based and Drosophila models, we examined the role of alternative ternary complex factors that may function in place of eIF2, including eIF2A, eIF2D, DENR and MCTS1. Among these factors, DENR knockdown had the greatest inhibitory effect on RAN translation of expanded GGGGCC and CGG repeat reporters and its reduction improved the survival of Drosophila expressing expanded GGGGCC repeats. Taken together, these data support a role for alternative initiation factors in RAN translation and suggest these may serve as novel therapeutic targets in neurodegenerative disease.
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Affiliation(s)
- Katelyn M Green
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Shannon L Miller
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Indranil Malik
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
- VA Ann Arbor Healthcare System, Ann Arbor, MI, USA
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26
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Marlin E, Viu-Idocin C, Arrasate M, Aragón T. The Role and Therapeutic Potential of the Integrated Stress Response in Amyotrophic Lateral Sclerosis. Int J Mol Sci 2022; 23:ijms23147823. [PMID: 35887167 PMCID: PMC9321386 DOI: 10.3390/ijms23147823] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/08/2022] [Accepted: 07/09/2022] [Indexed: 02/06/2023] Open
Abstract
In amyotrophic lateral sclerosis (ALS) patients, loss of cellular homeostasis within cortical and spinal cord motor neurons triggers the activation of the integrated stress response (ISR), an intracellular signaling pathway that remodels translation and promotes a gene expression program aimed at coping with stress. Beyond its neuroprotective role, under regimes of chronic or excessive stress, ISR can also promote cell/neuronal death. Given the two-edged sword nature of ISR, many experimental attempts have tried to establish the therapeutic potential of ISR enhancement or inhibition in ALS. This review discusses the complex interplay between ISR and disease progression in different models of ALS, as well as the opportunities and limitations of ISR modulation in the hard quest to find an effective therapy for ALS.
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Affiliation(s)
- Elías Marlin
- Neuroscience Program, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain;
- Gene Therapy and Regulation of Gene Expression Program, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain
- School of Medicine, University of Navarra, 31008 Pamplona, Spain
- Neuroscience Department, Navarra Institute for Health Research (IdiSNA), University of Navarra, 31008 Pamplona, Spain
| | | | - Montserrat Arrasate
- Neuroscience Program, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain;
- School of Medicine, University of Navarra, 31008 Pamplona, Spain
- Neuroscience Department, Navarra Institute for Health Research (IdiSNA), University of Navarra, 31008 Pamplona, Spain
- Correspondence: (M.A.); (T.A.)
| | - Tomás Aragón
- Gene Therapy and Regulation of Gene Expression Program, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain
- Neuroscience Department, Navarra Institute for Health Research (IdiSNA), University of Navarra, 31008 Pamplona, Spain
- Correspondence: (M.A.); (T.A.)
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27
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Baud A, Derbis M, Tutak K, Sobczak K. Partners in crime: Proteins implicated in
RNA
repeat expansion diseases. WIRES RNA 2022; 13:e1709. [PMID: 35229468 PMCID: PMC9539487 DOI: 10.1002/wrna.1709] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 11/06/2022]
Affiliation(s)
- Anna Baud
- Department of Gene Expression Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University Poznan Poland
| | - Magdalena Derbis
- Department of Gene Expression Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University Poznan Poland
| | - Katarzyna Tutak
- Department of Gene Expression Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University Poznan Poland
| | - Krzysztof Sobczak
- Department of Gene Expression Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University Poznan Poland
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28
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Zhao C, Liao Y, Rahaman A, Kumar V. Towards Understanding the Relationship Between ER Stress and Unfolded Protein Response in Amyotrophic Lateral Sclerosis. Front Aging Neurosci 2022; 14:892518. [PMID: 35783140 PMCID: PMC9248913 DOI: 10.3389/fnagi.2022.892518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/18/2022] [Indexed: 11/13/2022] Open
Abstract
Biological stress due to the aberrant buildup of misfolded/unfolded proteins in the endoplasmic reticulum (ER) is considered a key reason behind many human neurodegenerative diseases. Cells adapted to ER stress through the activation of an integrated signal transduction pathway known as the unfolded protein response (UPR). Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by degeneration of the motor system. It has largely been known that ER stress plays an important role in the pathogenesis of ALS through the dysregulation of proteostasis. Moreover, accumulating evidence indicates that ER stress and UPR are important players in TDP-43 pathology. In this mini-review, the complex interplay between ER stress and the UPR in ALS and TDP-43 pathology will be explored by taking into account the studies from in vitro and in vivo models of ALS. We also discuss therapeutic strategies to control levels of ER stress and UPR signaling components that have contrasting effects on ALS pathogenesis.
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Affiliation(s)
- Chenxuan Zhao
- School of Engineering, College of Technology and Business, Guangzhou, China
| | - Yong Liao
- Center of Scientific Research, Maoming People’s Hospital, Maoming, China
- *Correspondence: Yong Liao Vijay Kumar
| | - Abdul Rahaman
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Vijay Kumar
- Amity Institute of Neuropsychology & Neurosciences (AINN), Amity University, Noida, India
- *Correspondence: Yong Liao Vijay Kumar
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29
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Czuppa M, Dhingra A, Zhou Q, Schludi C, König L, Scharf E, Farny D, Dalmia A, Täger J, Castillo-Lizardo M, Katona E, Mori K, Aumer T, Schelter F, Müller M, Carell T, Kalliokoski T, Messinger J, Rizzu P, Heutink P, Edbauer D. Drug screen in iPSC-Neurons identifies nucleoside analogs as inhibitors of (G 4C 2) n expression in C9orf72 ALS/FTD. Cell Rep 2022; 39:110913. [PMID: 35675776 DOI: 10.1016/j.celrep.2022.110913] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 12/22/2021] [Accepted: 05/12/2022] [Indexed: 11/03/2022] Open
Abstract
An intronic (G4C2)n expansion in C9orf72 causes amyotrophic lateral sclerosis and frontotemporal dementia primarily through gain-of-function mechanisms: the accumulation of sense and antisense repeat RNA foci and dipeptide repeat (DPR) proteins (poly-GA/GP/GR/PA/PR) translated from repeat RNA. To therapeutically block this pathway, we screen a library of 1,430 approved drugs and known bioactive compounds in patient-derived induced pluripotent stem cell-derived neurons (iPSC-Neurons) for inhibitors of DPR expression. The clinically used guanosine/cytidine analogs decitabine, entecavir, and nelarabine reduce poly-GA/GP expression, with decitabine being the most potent. Hit compounds nearly abolish sense and antisense RNA foci and reduce expression of the repeat-containing nascent C9orf72 RNA transcript and its mature mRNA with minimal effects on global gene expression, suggesting that they specifically act on repeat transcription. Importantly, decitabine treatment reduces (G4C2)n foci and DPRs in C9orf72 BAC transgenic mice. Our findings suggest that nucleoside analogs are a promising compound class for therapeutic development in C9orf72 repeat-expansion-associated disorders.
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Affiliation(s)
- Mareike Czuppa
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Ashutosh Dhingra
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany.
| | - Qihui Zhou
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Carina Schludi
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Laura König
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Elisabeth Scharf
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Daniel Farny
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Anupriya Dalmia
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Joachim Täger
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | | | - Eszter Katona
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Kohji Mori
- Psychiatry, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Tina Aumer
- Ludwig-Maximilians-University Munich, Faculty of Chemistry and Pharmacy, Munich, Germany
| | - Florian Schelter
- Ludwig-Maximilians-University Munich, Faculty of Chemistry and Pharmacy, Munich, Germany
| | - Markus Müller
- Ludwig-Maximilians-University Munich, Faculty of Chemistry and Pharmacy, Munich, Germany
| | - Thomas Carell
- Ludwig-Maximilians-University Munich, Faculty of Chemistry and Pharmacy, Munich, Germany
| | | | - Josef Messinger
- Orion Corporation Orion Pharma, Medicine Design, Espoo, Finland
| | - Patrizia Rizzu
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Peter Heutink
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany; Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Dieter Edbauer
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany; Ludwig-Maximilians-University Munich, Graduate School of Systemic Neurosciences (GSN), Munich, Germany.
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30
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Verdone BM, Cicardi ME, Wen X, Sriramoji S, Russell K, Markandaiah SS, Jensen BK, Krishnamurthy K, Haeusler AR, Pasinelli P, Trotti D. A mouse model with widespread expression of the C9orf72-linked glycine-arginine dipeptide displays non-lethal ALS/FTD-like phenotypes. Sci Rep 2022; 12:5644. [PMID: 35379876 PMCID: PMC8979946 DOI: 10.1038/s41598-022-09593-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 03/25/2022] [Indexed: 12/14/2022] Open
Abstract
Translation of the hexanucleotide G4C2 expansion associated with C9orf72 amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD) produces five different dipeptide repeat protein (DPR) species that can confer toxicity. There is yet much to learn about the contribution of a single DPR to disease pathogenesis. We show here that a short repeat length is sufficient for the DPR poly-GR to confer neurotoxicity in vitro, a phenomenon previously unobserved. This toxicity is also reported in vivo in our novel knock-in mouse model characterized by widespread central nervous system (CNS) expression of the short-length poly-GR. We observe sex-specific chronic ALS/FTD-like phenotypes in these mice, including mild motor neuron loss, but no TDP-43 mis-localization, as well as motor and cognitive impairments. We suggest that this model can serve as the foundation for phenotypic exacerbation through second-hit forms of stress.
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Affiliation(s)
- Brandie Morris Verdone
- Jefferson Weinberg ALS Center, Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - Maria Elena Cicardi
- Jefferson Weinberg ALS Center, Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - Xinmei Wen
- Jefferson Weinberg ALS Center, Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - Sindhu Sriramoji
- Jefferson Weinberg ALS Center, Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - Katelyn Russell
- Jefferson Weinberg ALS Center, Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - Shashirekha S Markandaiah
- Jefferson Weinberg ALS Center, Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - Brigid K Jensen
- Jefferson Weinberg ALS Center, Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - Karthik Krishnamurthy
- Jefferson Weinberg ALS Center, Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - Aaron R Haeusler
- Jefferson Weinberg ALS Center, Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - Piera Pasinelli
- Jefferson Weinberg ALS Center, Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA.
| | - Davide Trotti
- Jefferson Weinberg ALS Center, Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA.
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31
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Sidhom E, O’Brien JT, Butcher AJ, Smith HL, Mallucci GR, Underwood BR. Targeting the Unfolded Protein Response as a Disease-Modifying Pathway in Dementia. Int J Mol Sci 2022; 23:2021. [PMID: 35216136 PMCID: PMC8877151 DOI: 10.3390/ijms23042021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 01/19/2022] [Accepted: 01/26/2022] [Indexed: 01/27/2023] Open
Abstract
Dementia is a global medical and societal challenge; it has devastating personal, social and economic costs, which will increase rapidly as the world's population ages. Despite this, there are no disease-modifying treatments for dementia; current therapy modestly improves symptoms but does not change the outcome. Therefore, new treatments are urgently needed-particularly any that can slow down the disease's progression. Many of the neurodegenerative diseases that lead to dementia are characterised by common pathological responses to abnormal protein production and misfolding in brain cells, raising the possibility of the broad application of therapeutics that target these common processes. The unfolded protein response (UPR) is one such mechanism. The UPR is a highly conserved cellular stress response to abnormal protein folding and is widely dysregulated in neurodegenerative diseases. In this review, we describe the basic machinery of the UPR, as well as the evidence for its overactivation and pathogenicity in dementia, and for the marked neuroprotective effects of its therapeutic manipulation in murine models of these disorders. We discuss drugs identified as potential UPR-modifying therapeutic agents-in particular the licensed antidepressant trazodone-and we review epidemiological and trial data from their use in human populations. Finally, we explore future directions for investigating the potential benefit of using trazodone or similar UPR-modulating compounds for disease modification in patients with dementia.
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Affiliation(s)
- Emad Sidhom
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK; (E.S.); (A.J.B.); (H.L.S.); (G.R.M.)
- Department of Clinical Neurosciences, UK Dementia Research Institute, University of Cambridge, Cambridge CB2 0AH, UK
- Cambridgeshire and Peterborough NHS Foundation Trust, Windsor Research Unit, Fulbourn Hospital, Cambridge CB21 5EF, UK
- Gnodde Goldman Sachs Translational Neuroscience Unit, Windsor Research Unit, University of Cambridge, Cambridge CB2 1TN, UK
| | - John T. O’Brien
- Department of Psychiatry, University of Cambridge, Herchel Smith Building, Forvie Site, Cambridge CB2 0SZ, UK;
| | - Adrian J. Butcher
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK; (E.S.); (A.J.B.); (H.L.S.); (G.R.M.)
- Department of Clinical Neurosciences, UK Dementia Research Institute, University of Cambridge, Cambridge CB2 0AH, UK
| | - Heather L. Smith
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK; (E.S.); (A.J.B.); (H.L.S.); (G.R.M.)
- Department of Clinical Neurosciences, UK Dementia Research Institute, University of Cambridge, Cambridge CB2 0AH, UK
| | - Giovanna R. Mallucci
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK; (E.S.); (A.J.B.); (H.L.S.); (G.R.M.)
- Department of Clinical Neurosciences, UK Dementia Research Institute, University of Cambridge, Cambridge CB2 0AH, UK
| | - Benjamin R. Underwood
- Cambridgeshire and Peterborough NHS Foundation Trust, Windsor Research Unit, Fulbourn Hospital, Cambridge CB21 5EF, UK
- Gnodde Goldman Sachs Translational Neuroscience Unit, Windsor Research Unit, University of Cambridge, Cambridge CB2 1TN, UK
- Department of Psychiatry, University of Cambridge, Herchel Smith Building, Forvie Site, Cambridge CB2 0SZ, UK;
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32
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Zhang Y, Glineburg MR, Basrur V, Conlon K, Wright SE, Krans A, Hall DA, Todd PK. Mechanistic convergence across initiation sites for RAN translation in fragile X associated tremor ataxia syndrome. Hum Mol Genet 2022; 31:2317-2332. [PMID: 35137065 PMCID: PMC9307318 DOI: 10.1093/hmg/ddab353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 11/30/2021] [Accepted: 12/06/2021] [Indexed: 11/13/2022] Open
Abstract
Repeat associated non-AUG (RAN) translation of CGG repeats in the 5'UTR of FMR1 produces toxic proteins that contribute to fragile X-associated tremor/ataxia syndrome (FXTAS) pathogenesis. The most abundant RAN product, FMRpolyG, initiates predominantly at an ACG upstream of the repeat. Accurate FMRpolyG measurements in FXTAS patients are lacking. We used data-dependent acquisition and parallel reaction monitoring (PRM) mass spectrometry coupled with stable isotope labeled standard peptides to identify signature FMRpolyG fragments in patient samples. Following immunoprecipitation, PRM detected FMRpolyG signature peptides in transfected cells, and FXTAS tissues and cells, but not in controls. We identified two amino-terminal peptides: an ACG-initiated Ac-MEAPLPGGVR and a GUG-initiated Ac-TEAPLPGGVR, as well as evidence for RAN translation initiation within the CGG repeat itself in two reading frames. Initiation at all sites increased following cellular stress, decreased following eIF1 overexpression and was eIF4A and M7G cap-dependent. These data demonstrate that FMRpolyG is quantifiable in human samples and FMR1 RAN translation initiates via similar mechanisms for near-cognate codons and within the repeat through processes dependent on available initiation factors and cellular environment.
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Affiliation(s)
- Yuan Zhang
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA,Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha 410008, China
| | - M Rebecca Glineburg
- To whom correspondence should be addressed at: Todd Lab (ATTN: Drs Glineburg and Todd), 4005 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA. Tel: +1 7346155632; Fax: +1 7346479777; ;
| | | | - Kevin Conlon
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Shannon E Wright
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Amy Krans
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Deborah A Hall
- Department of Neurological Sciences, Rush University, Chicago, IL, USA
| | - Peter K Todd
- To whom correspondence should be addressed at: Todd Lab (ATTN: Drs Glineburg and Todd), 4005 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA. Tel: +1 7346155632; Fax: +1 7346479777; ;
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33
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Benson BC, Shaw PJ, Azzouz M, Highley JR, Hautbergue GM. Proteinopathies as Hallmarks of Impaired Gene Expression, Proteostasis and Mitochondrial Function in Amyotrophic Lateral Sclerosis. Front Neurosci 2022; 15:783624. [PMID: 35002606 PMCID: PMC8733206 DOI: 10.3389/fnins.2021.783624] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Accepted: 11/26/2021] [Indexed: 01/15/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal adult-onset neurodegenerative disease characterized by progressive degeneration of upper and lower motor neurons. As with the majority of neurodegenerative diseases, the pathological hallmarks of ALS involve proteinopathies which lead to the formation of various polyubiquitylated protein aggregates in neurons and glia. ALS is a highly heterogeneous disease, with both familial and sporadic forms arising from the convergence of multiple disease mechanisms, many of which remain elusive. There has been considerable research effort invested into exploring these disease mechanisms and in recent years dysregulation of RNA metabolism and mitochondrial function have emerged as of crucial importance to the onset and development of ALS proteinopathies. Widespread alterations of the RNA metabolism and post-translational processing of proteins lead to the disruption of multiple biological pathways. Abnormal mitochondrial structure, impaired ATP production, dysregulation of energy metabolism and calcium homeostasis as well as apoptosis have been implicated in the neurodegenerative process. Dysfunctional mitochondria further accumulate in ALS motor neurons and reflect a wider failure of cellular quality control systems, including mitophagy and other autophagic processes. Here, we review the evidence for RNA and mitochondrial dysfunction as some of the earliest critical pathophysiological events leading to the development of ALS proteinopathies, explore their relative pathological contributions and their points of convergence with other key disease mechanisms. This review will focus primarily on mutations in genes causing four major types of ALS (C9ORF72, SOD1, TARDBP/TDP-43, and FUS) and in protein homeostasis genes (SQSTM1, OPTN, VCP, and UBQLN2) as well as sporadic forms of the disease. Finally, we will look to the future of ALS research and how an improved understanding of central mechanisms underpinning proteinopathies might inform research directions and have implications for the development of novel therapeutic approaches.
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Affiliation(s)
- Bridget C Benson
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom
| | - Pamela J Shaw
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom.,Neuroscience Institute, University of Sheffield, Sheffield, United Kingdom
| | - Mimoun Azzouz
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom.,Neuroscience Institute, University of Sheffield, Sheffield, United Kingdom.,Healthy Lifespan Institute (HELSI), University of Sheffield, Sheffield, United Kingdom
| | - J Robin Highley
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom.,Neuroscience Institute, University of Sheffield, Sheffield, United Kingdom.,Healthy Lifespan Institute (HELSI), University of Sheffield, Sheffield, United Kingdom
| | - Guillaume M Hautbergue
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom.,Neuroscience Institute, University of Sheffield, Sheffield, United Kingdom.,Healthy Lifespan Institute (HELSI), University of Sheffield, Sheffield, United Kingdom
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34
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Pasniceanu IS, Atwal MS, Souza CDS, Ferraiuolo L, Livesey MR. Emerging Mechanisms Underpinning Neurophysiological Impairments in C9ORF72 Repeat Expansion-Mediated Amyotrophic Lateral Sclerosis/Frontotemporal Dementia. Front Cell Neurosci 2022; 15:784833. [PMID: 34975412 PMCID: PMC8715728 DOI: 10.3389/fncel.2021.784833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/10/2021] [Indexed: 12/15/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are characterized by degeneration of upper and lower motor neurons and neurons of the prefrontal cortex. The emergence of the C9ORF72 hexanucleotide repeat expansion mutation as the leading genetic cause of ALS and FTD has led to a progressive understanding of the multiple cellular pathways leading to neuronal degeneration. Disturbances in neuronal function represent a major subset of these mechanisms and because such functional perturbations precede degeneration, it is likely that impaired neuronal function in ALS/FTD plays an active role in pathogenesis. This is supported by the fact that ALS/FTD patients consistently present with neurophysiological impairments prior to any apparent degeneration. In this review we summarize how the discovery of the C9ORF72 repeat expansion mutation has contributed to the current understanding of neuronal dysfunction in ALS/FTD. Here, we discuss the impact of the repeat expansion on neuronal function in relation to intrinsic excitability, synaptic, network and ion channel properties, highlighting evidence of conserved and divergent pathophysiological impacts between cortical and motor neurons and the influence of non-neuronal cells. We further highlight the emerging association between these dysfunctional properties with molecular mechanisms of the C9ORF72 mutation that appear to include roles for both, haploinsufficiency of the C9ORF72 protein and aberrantly generated dipeptide repeat protein species. Finally, we suggest that relating key pathological observations in C9ORF72 repeat expansion ALS/FTD patients to the mechanistic impact of the C9ORF72 repeat expansion on neuronal function will lead to an improved understanding of how neurophysiological dysfunction impacts upon pathogenesis.
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Affiliation(s)
- Iris-Stefania Pasniceanu
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Manpreet Singh Atwal
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Cleide Dos Santos Souza
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Laura Ferraiuolo
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Matthew R Livesey
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
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35
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Licata NV, Cristofani R, Salomonsson S, Wilson KM, Kempthorne L, Vaizoglu D, D’Agostino VG, Pollini D, Loffredo R, Pancher M, Adami V, Bellosta P, Ratti A, Viero G, Quattrone A, Isaacs AM, Poletti A, Provenzani A. C9orf72 ALS/FTD dipeptide repeat protein levels are reduced by small molecules that inhibit PKA or enhance protein degradation. EMBO J 2022; 41:e105026. [PMID: 34791698 PMCID: PMC8724771 DOI: 10.15252/embj.2020105026] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 09/21/2021] [Accepted: 10/12/2021] [Indexed: 11/09/2022] Open
Abstract
Intronic GGGGCC (G4C2) hexanucleotide repeat expansion within the human C9orf72 gene represents the most common cause of familial forms of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) (C9ALS/FTD). Repeat-associated non-AUG (RAN) translation of repeat-containing C9orf72 RNA results in the production of neurotoxic dipeptide-repeat proteins (DPRs). Here, we developed a high-throughput drug screen for the identification of positive and negative modulators of DPR levels. We found that HSP90 inhibitor geldanamycin and aldosterone antagonist spironolactone reduced DPR levels by promoting protein degradation via the proteasome and autophagy pathways respectively. Surprisingly, cAMP-elevating compounds boosting protein kinase A (PKA) activity increased DPR levels. Inhibition of PKA activity, by both pharmacological and genetic approaches, reduced DPR levels in cells and rescued pathological phenotypes in a Drosophila model of C9ALS/FTD. Moreover, knockdown of PKA-catalytic subunits correlated with reduced translation efficiency of DPRs, while the PKA inhibitor H89 reduced endogenous DPR levels in C9ALS/FTD patient-derived iPSC motor neurons. Together, our results suggest new and druggable pathways modulating DPR levels in C9ALS/FTD.
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Affiliation(s)
- Nausicaa V Licata
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Riccardo Cristofani
- Dipartimento di Scienze Farmacologiche e BiomolecolariUniversità degli Studi di MilanoMilanItaly
| | - Sally Salomonsson
- Department of Neurodegenerative DiseaseUCL Queen Square Institute of NeurologyLondonUK
- UK Dementia Research Institute at UCLUCL Queen Square Institute of NeurologyLondonUK
| | - Katherine M Wilson
- Department of Neurodegenerative DiseaseUCL Queen Square Institute of NeurologyLondonUK
- UK Dementia Research Institute at UCLUCL Queen Square Institute of NeurologyLondonUK
| | - Liam Kempthorne
- Department of Neurodegenerative DiseaseUCL Queen Square Institute of NeurologyLondonUK
- UK Dementia Research Institute at UCLUCL Queen Square Institute of NeurologyLondonUK
| | - Deniz Vaizoglu
- Department of Neurodegenerative DiseaseUCL Queen Square Institute of NeurologyLondonUK
- UK Dementia Research Institute at UCLUCL Queen Square Institute of NeurologyLondonUK
| | - Vito G D’Agostino
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Daniele Pollini
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Rosa Loffredo
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Michael Pancher
- HTS Core Facility, Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Valentina Adami
- HTS Core Facility, Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Paola Bellosta
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
- Department of MedicineNYU at Grossman School of MedicineNYUSA
| | - Antonia Ratti
- Department of NeurologyStroke Unit and Laboratory of NeuroscienceIstituto Auxologico Italiano, IRCCSMilanItaly
- Dipartimento di Biotecnologie Mediche e Medicina TraslazionaleUniversità degli Studi di MilanoMilanItaly
| | | | - Alessandro Quattrone
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Adrian M Isaacs
- Department of Neurodegenerative DiseaseUCL Queen Square Institute of NeurologyLondonUK
- UK Dementia Research Institute at UCLUCL Queen Square Institute of NeurologyLondonUK
| | - Angelo Poletti
- Dipartimento di Scienze Farmacologiche e BiomolecolariUniversità degli Studi di MilanoMilanItaly
| | - Alessandro Provenzani
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
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36
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Castelli LM, Benson BC, Huang WP, Lin YH, Hautbergue GM. RNA Helicases in Microsatellite Repeat Expansion Disorders and Neurodegeneration. Front Genet 2022; 13:886563. [PMID: 35646086 PMCID: PMC9133428 DOI: 10.3389/fgene.2022.886563] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/25/2022] [Indexed: 11/17/2022] Open
Abstract
Short repeated sequences of 3-6 nucleotides are causing a growing number of over 50 microsatellite expansion disorders, which mainly present with neurodegenerative features. Although considered rare diseases in relation to the relatively low number of cases, these primarily adult-onset conditions, often debilitating and fatal in absence of a cure, collectively pose a large burden on healthcare systems in an ageing world population. The pathological mechanisms driving disease onset are complex implicating several non-exclusive mechanisms of neuronal injury linked to RNA and protein toxic gain- and loss- of functions. Adding to the complexity of pathogenesis, microsatellite repeat expansions are polymorphic and found in coding as well as in non-coding regions of genes. They form secondary and tertiary structures involving G-quadruplexes and atypical helices in repeated GC-rich sequences. Unwinding of these structures by RNA helicases plays multiple roles in the expression of genes including repeat-associated non-AUG (RAN) translation of polymeric-repeat proteins with aggregating and cytotoxic properties. Here, we will briefly review the pathogenic mechanisms mediated by microsatellite repeat expansions prior to focus on the RNA helicases eIF4A, DDX3X and DHX36 which act as modifiers of RAN translation in C9ORF72-linked amyotrophic lateral sclerosis/frontotemporal dementia (C9ORF72-ALS/FTD) and Fragile X-associated tremor/ataxia syndrome (FXTAS). We will further review the RNA helicases DDX5/17, DHX9, Dicer and UPF1 which play additional roles in the dysregulation of RNA metabolism in repeat expansion disorders. In addition, we will contrast these with the roles of other RNA helicases such as DDX19/20, senataxin and others which have been associated with neurodegeneration independently of microsatellite repeat expansions. Finally, we will discuss the challenges and potential opportunities that are associated with the targeting of RNA helicases for the development of future therapeutic approaches.
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Affiliation(s)
- Lydia M Castelli
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Bridget C Benson
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Wan-Ping Huang
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Ya-Hui Lin
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Guillaume M Hautbergue
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, United Kingdom.,Neuroscience Institute, University of Sheffield, Sheffield, United Kingdom.,Healthy Lifespan Institute (HELSI), University of Sheffield, Sheffield, United Kingdom
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37
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Guo S, Nguyen L, Ranum LPW. RAN proteins in neurodegenerative disease: Repeating themes and unifying therapeutic strategies. Curr Opin Neurobiol 2021; 72:160-170. [PMID: 34953315 DOI: 10.1016/j.conb.2021.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/01/2021] [Accepted: 11/02/2021] [Indexed: 11/29/2022]
Abstract
Microsatellite-expansion mutations cause >50 neurological diseases but there are no effective treatments. Mechanistic studies have historically focused on protein loss-of-function and protein or RNA gain-of-function effects. It is now clear that many expansion mutations are bidirectionally transcribed producing two toxic expansion RNAs, which can produce up to six mutant proteins by repeat associated non-AUG (RAN) translation. Multiple types of RAN proteins have been shown to be toxic in cell and animal models, to lead to common types of neuropathological changes, and to dysregulate key pathways. How RAN proteins are produced without the canonical AUG or close-cognate AUG-like initiation codons is not yet completely understood but RNA structure, flanking sequences and stress pathways have been shown to be important. Here, we summarize recent progress in understanding the role of RAN proteins, mechanistic insights into their production, and the identification of novel therapeutic strategies that may be applicable across these neurodegenerative disorders.
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Affiliation(s)
- Shu Guo
- Center for NeuroGenetics, College of Medicine, University of Florida, USA; Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, USA
| | - Lien Nguyen
- Center for NeuroGenetics, College of Medicine, University of Florida, USA; Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, USA.
| | - Laura P W Ranum
- Center for NeuroGenetics, College of Medicine, University of Florida, USA; Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, USA; Genetics Institute, University of Florida, USA; McKnight Brain Institute, University of Florida, USA; Norman Fixel Institute for Neurological Diseases, University of Florida, USA.
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38
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Malik I, Tseng Y, Wright SE, Zheng K, Ramaiyer P, Green KM, Todd PK. SRSF protein kinase 1 modulates RAN translation and suppresses CGG repeat toxicity. EMBO Mol Med 2021; 13:e14163. [PMID: 34542927 PMCID: PMC8573603 DOI: 10.15252/emmm.202114163] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 08/28/2021] [Accepted: 08/30/2021] [Indexed: 11/20/2022] Open
Abstract
Transcribed CGG repeat expansions cause neurodegeneration in Fragile X-associated tremor/ataxia syndrome (FXTAS). CGG repeat RNAs sequester RNA-binding proteins (RBPs) into nuclear foci and undergo repeat-associated non-AUG (RAN) translation into toxic peptides. To identify proteins involved in these processes, we employed a CGG repeat RNA-tagging system to capture repeat-associated RBPs by mass spectrometry in mammalian cells. We identified several SR (serine/arginine-rich) proteins that interact selectively with CGG repeats basally and under cellular stress. These proteins modify toxicity in a Drosophila model of FXTAS. Pharmacologic inhibition of serine/arginine protein kinases (SRPKs), which alter SRSF protein phosphorylation, localization, and activity, directly inhibits RAN translation of CGG and GGGGCC repeats (associated with C9orf72 ALS/FTD) and triggers repeat RNA retention in the nucleus. Lowering SRPK expression suppressed toxicity in both FXTAS and C9orf72 ALS/FTD model flies, and SRPK inhibitors suppressed CGG repeat toxicity in rodent neurons. Together, these findings demonstrate roles for CGG repeat RNA binding proteins in RAN translation and repeat toxicity and support further evaluation of SRPK inhibitors in modulating RAN translation associated with repeat expansion disorders.
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Affiliation(s)
- Indranil Malik
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
| | - Yi‐Ju Tseng
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
- Cellular and Molecular Biology Graduate ProgramUniversity of MichiganAnn ArborMIUSA
| | - Shannon E Wright
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
- Neuroscience Graduate ProgramUniversity of MichiganAnn ArborMIUSA
| | - Kristina Zheng
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
| | | | - Katelyn M Green
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
- Cellular and Molecular Biology Graduate ProgramUniversity of MichiganAnn ArborMIUSA
| | - Peter K Todd
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
- Ann Arbor Veterans Administration HealthcareAnn ArborMIUSA
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39
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Torres P, Cabral-Miranda F, Gonzalez-Teuber V, Hetz C. Proteostasis deregulation as a driver of C9ORF72 pathogenesis. J Neurochem 2021; 159:941-957. [PMID: 34679204 DOI: 10.1111/jnc.15529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 10/16/2021] [Accepted: 10/18/2021] [Indexed: 12/21/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are two related neurodegenerative disorders that display overlapping features. The hexanucleotide repeat expansion GGGGCC (G4 C2 ) in C9ORF72 gene has been causally linked to both ALS and FTD emergence, thus opening a novel potential therapeutic target for disease intervention. The main driver of C9ORF72 pathology is the disruption of distinct cellular processes involved in the function of the proteostasis network. Here we discuss main findings relating to the induction of neurodegeneration by C9ORF72 mutation and proteostasis deregulation, highlighting the role of the endoplasmic reticulum stress, nuclear transport, and autophagy in the disease process. We further discuss possible points of intervention to target proteostasis mediators to treat C9ORF72-linked ALS/FTD.
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Affiliation(s)
- Paulina Torres
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile, Santiago, Chile.,FONDAP Center for Geroscience, Brain Health, and Metabolism (GERO), Santiago, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Science, University of Chile, Santiago, Chile
| | - Felipe Cabral-Miranda
- Instituto de Ciências Biomédicas, Universidade do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Vicente Gonzalez-Teuber
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile, Santiago, Chile.,FONDAP Center for Geroscience, Brain Health, and Metabolism (GERO), Santiago, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Science, University of Chile, Santiago, Chile
| | - Claudio Hetz
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile, Santiago, Chile.,FONDAP Center for Geroscience, Brain Health, and Metabolism (GERO), Santiago, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Science, University of Chile, Santiago, Chile.,Buck Institute for Research on Aging, Novato, California, USA
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40
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Therapeutic strategies for C9orf72 amyotrophic lateral sclerosis and frontotemporal dementia. Curr Opin Neurol 2021; 34:748-755. [PMID: 34392299 PMCID: PMC8678157 DOI: 10.1097/wco.0000000000000984] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW An intronic G4C2 expansion mutation in C9orf72 is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia (C9-ALS/FTD). Although there are currently no treatments for this insidious, fatal disease, intense research has led to promising therapeutic strategies, which will be discussed here. RECENT FINDINGS Therapeutic strategies for C9-ALS/FTD have primarily focused on reducing the toxic effects of mutant expansion RNAs or the dipeptide repeat proteins (DPRs). The pathogenic effects of G4C2 expansion transcripts have been targeted using approaches aimed at promoting their degradation, inhibiting nuclear export or silencing transcription. Other promising strategies include immunotherapy to reduce the DPRs themselves, reducing RAN translation, removing the repeats using DNA or RNA editing and manipulation of downstream disease-altered stress granule pathways. Finally, understanding the molecular triggers that lead to pheno-conversion may lead to opportunities that can delay symptomatic disease onset. SUMMARY A large body of evidence implicates RAN-translated DPRs as a main driver of C9-ALS/FTD. Promising therapeutic strategies for these devastating diseases are being rapidly developed with several approaches already in or approaching clinical trials.
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41
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Malik I, Kelley CP, Wang ET, Todd PK. Molecular mechanisms underlying nucleotide repeat expansion disorders. Nat Rev Mol Cell Biol 2021; 22:589-607. [PMID: 34140671 PMCID: PMC9612635 DOI: 10.1038/s41580-021-00382-6] [Citation(s) in RCA: 131] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2021] [Indexed: 02/05/2023]
Abstract
The human genome contains over one million short tandem repeats. Expansion of a subset of these repeat tracts underlies over fifty human disorders, including common genetic causes of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (C9orf72), polyglutamine-associated ataxias and Huntington disease, myotonic dystrophy, and intellectual disability disorders such as Fragile X syndrome. In this Review, we discuss the four major mechanisms by which expansion of short tandem repeats causes disease: loss of function through transcription repression, RNA-mediated gain of function through gelation and sequestration of RNA-binding proteins, gain of function of canonically translated repeat-harbouring proteins, and repeat-associated non-AUG translation of toxic repeat peptides. Somatic repeat instability amplifies these mechanisms and influences both disease age of onset and tissue specificity of pathogenic features. We focus on the crosstalk between these disease mechanisms, and argue that they often synergize to drive pathogenesis. We also discuss the emerging native functions of repeat elements and how their dynamics might contribute to disease at a larger scale than currently appreciated. Lastly, we propose that lynchpins tying these disease mechanisms and native functions together offer promising therapeutic targets with potential shared applications across this class of human disorders.
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Affiliation(s)
- Indranil Malik
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Chase P Kelley
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
- Genetics and Genomics Graduate Program, University of Florida, Gainesville, FL, USA
| | - Eric T Wang
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL, USA.
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA.
- VA Ann Arbor Healthcare System, Ann Arbor, MI, USA.
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The porphyrin TMPyP4 inhibits elongation during the noncanonical translation of the FTLD/ALS-associated GGGGCC repeat in the C9orf72 gene. J Biol Chem 2021; 297:101120. [PMID: 34450161 PMCID: PMC8446798 DOI: 10.1016/j.jbc.2021.101120] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 08/15/2021] [Accepted: 08/23/2021] [Indexed: 12/24/2022] Open
Abstract
GGGGCC (G4C2) repeat expansion in the C9orf72 gene has been shown to cause frontotemporal lobar degeneration and amyotrophic lateral sclerosis. Dipeptide repeat proteins produced through repeat-associated non-AUG (RAN) translation are recognized as potential drivers for neurodegeneration. Therefore, selective inhibition of RAN translation could be a therapeutic avenue to treat these neurodegenerative diseases. It was previously known that the porphyrin TMPyP4 binds to G4C2 repeat RNA. However, the consequences of this interaction have not been well characterized. Here, we confirmed that TMPyP4 inhibits C9orf72 G4C2 repeat translation in cellular and in in vitro translation systems. An artificial insertion of an AUG codon failed to cancel the translation inhibition, suggesting that TMPyP4 acts downstream of non-AUG translation initiation. Polysome profiling assays also revealed polysome retention on G4C2 repeat RNA, along with inhibition of translation, indicating that elongating ribosomes stall on G4C2 repeat RNA. Urea-resistant interaction between G4C2 repeat RNA and TMPyP4 likely contributes to this ribosome stalling and thus to selective inhibition of RAN translation. Taken together, our data reveal a novel mode of action of TMPyP4 as an inhibitor of G4C2 repeat translation elongation.
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Nuclear export and translation of circular repeat-containing intronic RNA in C9ORF72-ALS/FTD. Nat Commun 2021; 12:4908. [PMID: 34389711 PMCID: PMC8363653 DOI: 10.1038/s41467-021-25082-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 07/16/2021] [Indexed: 12/14/2022] Open
Abstract
C9ORF72 hexanucleotide GGGGCC repeat expansion is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Repeat-containing RNA mediates toxicity through nuclear granules and dipeptide repeat (DPR) proteins produced by repeat-associated non-AUG translation. However, it remains unclear how the intron-localized repeats are exported and translated in the cytoplasm. We use single molecule imaging approach to examine the molecular identity and spatiotemporal dynamics of the repeat RNA. We demonstrate that the spliced intron with G-rich repeats is stabilized in a circular form due to defective lariat debranching. The spliced circular intron, instead of pre-mRNA, serves as the translation template. The NXF1-NXT1 pathway plays an important role in the nuclear export of the circular intron and modulates toxic DPR production. This study reveals an uncharacterized disease-causing RNA species mediated by repeat expansion and demonstrates the importance of RNA spatial localization to understand disease etiology. Hexanucleotide repeat expansion in the intron 1 of the C9ORF72 gene can cause amyotrophic lateral sclerosis (ALS) and frontal temporal dementia (FTD). Here the authors use single molecule imaging to show nuclear export and translation of circular repeat-containing C9ORF72 intronic RNA.
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44
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Castelli LM, Cutillo L, Souza CDS, Sanchez-Martinez A, Granata I, Lin YH, Myszczynska MA, Heath PR, Livesey MR, Ning K, Azzouz M, Shaw PJ, Guarracino MR, Whitworth AJ, Ferraiuolo L, Milo M, Hautbergue GM. SRSF1-dependent inhibition of C9ORF72-repeat RNA nuclear export: genome-wide mechanisms for neuroprotection in amyotrophic lateral sclerosis. Mol Neurodegener 2021; 16:53. [PMID: 34376242 PMCID: PMC8353793 DOI: 10.1186/s13024-021-00475-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 07/16/2021] [Indexed: 12/13/2022] Open
Abstract
Background Loss of motor neurons in amyotrophic lateral sclerosis (ALS) leads to progressive paralysis and death. Dysregulation of thousands of RNA molecules with roles in multiple cellular pathways hinders the identification of ALS-causing alterations over downstream changes secondary to the neurodegenerative process. How many and which of these pathological gene expression changes require therapeutic normalisation remains a fundamental question. Methods Here, we investigated genome-wide RNA changes in C9ORF72-ALS patient-derived neurons and Drosophila, as well as upon neuroprotection taking advantage of our gene therapy approach which specifically inhibits the SRSF1-dependent nuclear export of pathological C9ORF72-repeat transcripts. This is a critical study to evaluate (i) the overall safety and efficacy of the partial depletion of SRSF1, a member of a protein family involved itself in gene expression, and (ii) a unique opportunity to identify neuroprotective RNA changes. Results Our study shows that manipulation of 362 transcripts out of 2257 pathological changes, in addition to inhibiting the nuclear export of repeat transcripts, is sufficient to confer neuroprotection in C9ORF72-ALS patient-derived neurons. In particular, expression of 90 disease-altered transcripts is fully reverted upon neuroprotection leading to the characterisation of a human C9ORF72-ALS disease-modifying gene expression signature. These findings were further investigated in vivo in diseased and neuroprotected Drosophila transcriptomes, highlighting a list of 21 neuroprotective changes conserved with 16 human orthologues in patient-derived neurons. We also functionally validated the high neuroprotective potential of one of these disease-modifying transcripts, demonstrating that inhibition of ALS-upregulated human KCNN1–3 (Drosophila SK) voltage-gated potassium channel orthologs mitigates degeneration of human motor neurons and Drosophila motor deficits. Conclusions Strikingly, the partial depletion of SRSF1 leads to expression changes in only a small proportion of disease-altered transcripts, indicating that not all RNA alterations need normalization and that the gene therapeutic approach is safe in the above preclinical models as it does not disrupt globally gene expression. The efficacy of this intervention is also validated at genome-wide level with transcripts modulated in the vast majority of biological processes affected in C9ORF72-ALS. Finally, the identification of a characteristic signature with key RNA changes modified in both the disease state and upon neuroprotection also provides potential new therapeutic targets and biomarkers. Supplementary Information The online version contains supplementary material available at 10.1186/s13024-021-00475-y.
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Affiliation(s)
- Lydia M Castelli
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, 385 Glossop Road, Sheffield, S10 2HQ, UK
| | - Luisa Cutillo
- School of Mathematics, University of Leeds, Leeds, LS2 9JT, UK
| | - Cleide Dos Santos Souza
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, 385 Glossop Road, Sheffield, S10 2HQ, UK
| | - Alvaro Sanchez-Martinez
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
| | - Ilaria Granata
- National Research Council of Italy, High Performance Computing and Networking Institute (ICAR-CNR), 111 Via Pietro Castellino, 80131, Naples, Italy
| | - Ya-Hui Lin
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, 385 Glossop Road, Sheffield, S10 2HQ, UK
| | - Monika A Myszczynska
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, 385 Glossop Road, Sheffield, S10 2HQ, UK
| | - Paul R Heath
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, 385 Glossop Road, Sheffield, S10 2HQ, UK
| | - Matthew R Livesey
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, 385 Glossop Road, Sheffield, S10 2HQ, UK.,Neuroscience Institute, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Ke Ning
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, 385 Glossop Road, Sheffield, S10 2HQ, UK.,Neuroscience Institute, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Mimoun Azzouz
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, 385 Glossop Road, Sheffield, S10 2HQ, UK.,Neuroscience Institute, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Pamela J Shaw
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, 385 Glossop Road, Sheffield, S10 2HQ, UK.,Neuroscience Institute, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Mario R Guarracino
- National Research Council of Italy, High Performance Computing and Networking Institute (ICAR-CNR), 111 Via Pietro Castellino, 80131, Naples, Italy
| | - Alexander J Whitworth
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
| | - Laura Ferraiuolo
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, 385 Glossop Road, Sheffield, S10 2HQ, UK.,Neuroscience Institute, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Marta Milo
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK. .,Present Address: AstraZeneca, Academy House, 136 Hills Road, Cambridge, CB2 8PA, UK.
| | - Guillaume M Hautbergue
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, 385 Glossop Road, Sheffield, S10 2HQ, UK. .,Neuroscience Institute, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
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45
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Mallucci GR, Klenerman D, Rubinsztein DC. Developing Therapies for Neurodegenerative Disorders: Insights from Protein Aggregation and Cellular Stress Responses. Annu Rev Cell Dev Biol 2021; 36:165-189. [PMID: 33021824 DOI: 10.1146/annurev-cellbio-040320-120625] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
As the world's population ages, neurodegenerative disorders are poised to become the commonest cause of death. Despite this, they remain essentially untreatable. Characterized pathologically both by the aggregation of disease-specific misfolded proteins and by changes in cellular stress responses, to date, therapeutic approaches have focused almost exclusively on reducing misfolded protein load-notably amyloid beta (Aβ) in Alzheimer's disease. The repeated failure of clinical trials has led to despondency over the possibility that these disorders will ever be treated. We argue that this is in fact a time for optimism: Targeting various generic stress responses is emerging as an increasingly promising means of modifying disease progression across these disorders. New treatments are approaching clinical trials, while novel means of targeting aggregates could eventually act preventively in early disease.
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Affiliation(s)
- Giovanna R Mallucci
- UK Dementia Research Institute at the University of Cambridge, Cambridge CB2 0AH, United Kingdom; .,Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, United Kingdom
| | - David Klenerman
- UK Dementia Research Institute at the University of Cambridge, Cambridge CB2 0AH, United Kingdom; .,Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - David C Rubinsztein
- UK Dementia Research Institute at the University of Cambridge, Cambridge CB2 0AH, United Kingdom; .,Cambridge Institute for Medical Research, Cambridge CB2 0XY, United Kingdom
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46
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Pereira JD, DuBreuil DM, Devlin AC, Held A, Sapir Y, Berezovski E, Hawrot J, Dorfman K, Chander V, Wainger BJ. Human sensorimotor organoids derived from healthy and amyotrophic lateral sclerosis stem cells form neuromuscular junctions. Nat Commun 2021; 12:4744. [PMID: 34362895 PMCID: PMC8346474 DOI: 10.1038/s41467-021-24776-4] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 07/06/2021] [Indexed: 02/07/2023] Open
Abstract
Human induced pluripotent stem cells (iPSC) hold promise for modeling diseases in individual human genetic backgrounds and thus for developing precision medicine. Here, we generate sensorimotor organoids containing physiologically functional neuromuscular junctions (NMJs) and apply the model to different subgroups of amyotrophic lateral sclerosis (ALS). Using a range of molecular, genomic, and physiological techniques, we identify and characterize motor neurons and skeletal muscle, along with sensory neurons, astrocytes, microglia, and vasculature. Organoid cultures derived from multiple human iPSC lines generated from individuals with ALS and isogenic lines edited to harbor familial ALS mutations show impairment at the level of the NMJ, as detected by both contraction and immunocytochemical measurements. The physiological resolution of the human NMJ synapse, combined with the generation of major cellular cohorts exerting autonomous and non-cell autonomous effects in motor and sensory diseases, may prove valuable to understand the pathophysiological mechanisms of ALS.
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Affiliation(s)
- João D Pereira
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Daniel M DuBreuil
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Anna-Claire Devlin
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Aaron Held
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Yechiam Sapir
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Eugene Berezovski
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - James Hawrot
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Katherine Dorfman
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Vignesh Chander
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Brian J Wainger
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
- Department of Anesthesiology, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA.
- Harvard Stem Cell Institute, Cambridge, MA, USA.
- Broad Institute of Harvard University and MIT, Cambridge, MA, USA.
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47
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Catanese A, Rajkumar S, Sommer D, Freisem D, Wirth A, Aly A, Massa‐López D, Olivieri A, Torelli F, Ioannidis V, Lipecka J, Guerrera IC, Zytnicki D, Ludolph A, Kabashi E, Mulaw MA, Roselli F, Böckers TM. Synaptic disruption and CREB-regulated transcription are restored by K + channel blockers in ALS. EMBO Mol Med 2021; 13:e13131. [PMID: 34125498 PMCID: PMC8261490 DOI: 10.15252/emmm.202013131] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 05/19/2021] [Accepted: 05/21/2021] [Indexed: 11/15/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease, which is still missing effective therapeutic strategies. Although manipulation of neuronal excitability has been tested in murine and human ALS models, it is still under debate whether neuronal activity might represent a valid target for efficient therapies. In this study, we exploited a combination of transcriptomics, proteomics, optogenetics and pharmacological approaches to investigate the activity-related pathological features of iPSC-derived C9orf72-mutant motoneurons (MN). We found that human ALSC9orf72 MN are characterized by accumulation of aberrant aggresomes, reduced expression of synaptic genes, loss of synaptic contacts and a dynamic "malactivation" of the transcription factor CREB. A similar phenotype was also found in TBK1-mutant MN and upon overexpression of poly(GA) aggregates in primary neurons, indicating a strong convergence of pathological phenotypes on synaptic dysregulation. Notably, these alterations, along with neuronal survival, could be rescued by treating ALS-related neurons with the K+ channel blockers Apamin and XE991, which, respectively, target the SK and the Kv7 channels. Thus, our study shows that restoring the activity-dependent transcriptional programme and synaptic composition exerts a neuroprotective effect on ALS disease progression.
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Affiliation(s)
- Alberto Catanese
- Institute of Anatomy and Cell BiologyUlm University School of MedicineUlmGermany
| | - Sandeep Rajkumar
- Institute of Anatomy and Cell BiologyUlm University School of MedicineUlmGermany
| | - Daniel Sommer
- Institute of Anatomy and Cell BiologyUlm University School of MedicineUlmGermany
| | - Dennis Freisem
- Institute of Anatomy and Cell BiologyUlm University School of MedicineUlmGermany
| | - Alexander Wirth
- Institute of Anatomy and Cell BiologyUlm University School of MedicineUlmGermany
| | - Amr Aly
- Institute of Anatomy and Cell BiologyUlm University School of MedicineUlmGermany
| | - David Massa‐López
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE)Ulm siteUlmGermany
| | - Andrea Olivieri
- Institute of Anatomy and Cell BiologyUlm University School of MedicineUlmGermany
| | - Federica Torelli
- Institute of Anatomy and Cell BiologyUlm University School of MedicineUlmGermany
| | - Valentin Ioannidis
- Institute of Anatomy and Cell BiologyUlm University School of MedicineUlmGermany
| | - Joanna Lipecka
- Proteomics platform NeckerINSERM US24/CNRS UMS3633Université de Paris – Structure Fédérative de Recherche NeckerParisFrance
| | - Ida Chiara Guerrera
- Proteomics platform NeckerINSERM US24/CNRS UMS3633Université de Paris – Structure Fédérative de Recherche NeckerParisFrance
| | - Daniel Zytnicki
- SPPIN ‐ Saints‐Pères Paris Institute for the NeurosciencesCNRSUniversité de ParisParis, Paris
| | - Albert Ludolph
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE)Ulm siteUlmGermany
- Department of NeurologyUlm University School of MedicineUlmGermany
| | - Edor Kabashi
- Institute of Translational Research for Neurological DisordersINSERM UMR 1163Imagine InstituteParisFrance
| | - Medhanie A Mulaw
- Internal Medicine I and Institute of Molecular Medicine and Stem Cell AgingMedical FacultyUniversity Hospital UlmUniversity of Ulm UniversityUlmGermany
| | - Francesco Roselli
- Institute of Anatomy and Cell BiologyUlm University School of MedicineUlmGermany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE)Ulm siteUlmGermany
- Department of NeurologyUlm University School of MedicineUlmGermany
| | - Tobias M Böckers
- Institute of Anatomy and Cell BiologyUlm University School of MedicineUlmGermany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE)Ulm siteUlmGermany
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48
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Tseng YJ, Sandwith SN, Green KM, Chambers AE, Krans A, Raimer HM, Sharlow ME, Reisinger MA, Richardson AE, Routh ED, Smaldino MA, Wang YH, Vaughn JP, Todd PK, Smaldino PJ. The RNA helicase DHX36-G4R1 modulates C9orf72 GGGGCC hexanucleotide repeat-associated translation. J Biol Chem 2021; 297:100914. [PMID: 34174288 PMCID: PMC8326427 DOI: 10.1016/j.jbc.2021.100914] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 06/02/2021] [Accepted: 06/22/2021] [Indexed: 12/26/2022] Open
Abstract
GGGGCC (G4C2) hexanucleotide repeat expansions in the endosomal trafficking gene C9orf72 are the most common genetic cause of ALS and frontotemporal dementia. Repeat-associated non-AUG (RAN) translation of this expansion through near-cognate initiation codon usage and internal ribosomal entry generates toxic proteins that accumulate in patients' brains and contribute to disease pathogenesis. The helicase protein DEAH-box helicase 36 (DHX36–G4R1) plays active roles in RNA and DNA G-quadruplex (G4) resolution in cells. As G4C2 repeats are known to form G4 structures in vitro, we sought to determine the impact of manipulating DHX36 expression on repeat transcription and RAN translation. Using a series of luciferase reporter assays both in cells and in vitro, we found that DHX36 depletion suppresses RAN translation in a repeat length–dependent manner, whereas overexpression of DHX36 enhances RAN translation from G4C2 reporter RNAs. Moreover, upregulation of RAN translation that is typically triggered by integrated stress response activation is prevented by loss of DHX36. These results suggest that DHX36 is active in regulating G4C2 repeat translation, providing potential implications for therapeutic development in nucleotide repeat expansion disorders.
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Affiliation(s)
- Yi-Ju Tseng
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA; Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, Michigan, USA
| | - Siara N Sandwith
- Department of Biology, Ball State University, Muncie, Indiana, USA
| | - Katelyn M Green
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Amy Krans
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Heather M Raimer
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia, USA
| | | | | | | | - Eric D Routh
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | | | - Yuh-Hwa Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia, USA
| | - James P Vaughn
- Division of Cancer Biology, NanoMedica LLC, Winston-Salem, North Carolina, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA; Department of Neurology, Ann Arbor VA Medical Center, Ann Arbor, Michigan, USA.
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49
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Nishimura AL, Arias N. Synaptopathy Mechanisms in ALS Caused by C9orf72 Repeat Expansion. Front Cell Neurosci 2021; 15:660693. [PMID: 34140881 PMCID: PMC8203826 DOI: 10.3389/fncel.2021.660693] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 05/03/2021] [Indexed: 12/14/2022] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a complex neurodegenerative disease caused by degeneration of motor neurons (MNs). ALS pathogenic features include accumulation of misfolded proteins, glutamate excitotoxicity, mitochondrial dysfunction at distal axon terminals, and neuronal cytoskeleton changes. Synergies between loss of C9orf72 functions and gain of function by toxic effects of repeat expansions also contribute to C9orf72-mediated pathogenesis. However, the impact of haploinsufficiency of C9orf72 on neurons and in synaptic functions requires further examination. As the motor neurons degenerate, the disease symptoms will lead to neurotransmission deficiencies in the brain, spinal cord, and neuromuscular junction. Altered neuronal excitability, synaptic morphological changes, and C9orf72 protein and DPR localization at the synapses, suggest a potential involvement of C9orf72 at synapses. In this review article, we provide a conceptual framework for assessing the putative involvement of C9orf72 as a synaptopathy, and we explore the underlying and common disease mechanisms with other neurodegenerative diseases. Finally, we reflect on the major challenges of understanding C9orf72-ALS as a synaptopathy focusing on integrating mitochondrial and neuronal cytoskeleton degeneration as biomarkers and potential targets to treat ALS neurodegeneration.
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Affiliation(s)
- Agnes L Nishimura
- Department of Basic and Clinical Neuroscience, UK Dementia Research Institute, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Natalia Arias
- Department of Basic and Clinical Neuroscience, UK Dementia Research Institute, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,INEUROPA, Instituto de Neurociencias del Principado de Asturias, Oviedo, Spain
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50
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Cicardi ME, Marrone L, Azzouz M, Trotti D. Proteostatic imbalance and protein spreading in amyotrophic lateral sclerosis. EMBO J 2021; 40:e106389. [PMID: 33792056 PMCID: PMC8126909 DOI: 10.15252/embj.2020106389] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 11/18/2020] [Accepted: 02/25/2021] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder whose exact causative mechanisms are still under intense investigation. Several lines of evidence suggest that the anatomical and temporal propagation of pathological protein species along the neural axis could be among the main driving mechanisms for the fast and irreversible progression of ALS pathology. Many ALS-associated proteins form intracellular aggregates as a result of their intrinsic prion-like properties and/or following impairment of the protein quality control systems. During the disease course, these mutated proteins and aberrant peptides are released in the extracellular milieu as soluble or aggregated forms through a variety of mechanisms. Internalization by recipient cells may seed further aggregation and amplify existing proteostatic imbalances, thus triggering a vicious cycle that propagates pathology in vulnerable cells, such as motor neurons and other susceptible neuronal subtypes. Here, we provide an in-depth review of ALS pathology with a particular focus on the disease mechanisms of seeding and transmission of the most common ALS-associated proteins, including SOD1, FUS, TDP-43, and C9orf72-linked dipeptide repeats. For each of these proteins, we report historical, biochemical, and pathological evidence of their behaviors in ALS. We further discuss the possibility to harness pathological proteins as biomarkers and reflect on the implications of these findings for future research.
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Affiliation(s)
- Maria Elena Cicardi
- Department of NeuroscienceWeinberg ALS CenterVickie and Jack Farber Institute for NeuroscienceThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Lara Marrone
- Department of NeuroscienceSheffield Institute for Translational Neuroscience (SITraN)University of SheffieldSheffieldUK
| | - Mimoun Azzouz
- Department of NeuroscienceSheffield Institute for Translational Neuroscience (SITraN)University of SheffieldSheffieldUK
| | - Davide Trotti
- Department of NeuroscienceWeinberg ALS CenterVickie and Jack Farber Institute for NeuroscienceThomas Jefferson UniversityPhiladelphiaPAUSA
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