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Irwin KE, Jasin P, Braunstein KE, Sinha IR, Garret MA, Bowden KD, Chang K, Troncoso JC, Moghekar A, Oh ES, Raitcheva D, Bartlett D, Miller T, Berry JD, Traynor BJ, Ling JP, Wong PC. A fluid biomarker reveals loss of TDP-43 splicing repression in presymptomatic ALS-FTD. Nat Med 2024; 30:382-393. [PMID: 38278991 PMCID: PMC10878965 DOI: 10.1038/s41591-023-02788-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 12/21/2023] [Indexed: 01/28/2024]
Abstract
Although loss of TAR DNA-binding protein 43 kDa (TDP-43) splicing repression is well documented in postmortem tissues of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), whether this abnormality occurs during early-stage disease remains unresolved. Cryptic exon inclusion reflects loss of function of TDP-43, and thus detection of proteins containing cryptic exon-encoded neoepitopes in cerebrospinal fluid (CSF) or blood could reveal the earliest stages of TDP-43 dysregulation in patients. Here we use a newly characterized monoclonal antibody specific to a TDP-43-dependent cryptic epitope (encoded by the cryptic exon found in HDGFL2) to show that loss of TDP-43 splicing repression occurs in ALS-FTD, including in presymptomatic C9orf72 mutation carriers. Cryptic hepatoma-derived growth factor-like protein 2 (HDGFL2) accumulates in CSF at significantly higher levels in familial ALS-FTD and sporadic ALS compared with controls and is elevated earlier than neurofilament light and phosphorylated neurofilament heavy chain protein levels in familial disease. Cryptic HDGFL2 can also be detected in blood of individuals with ALS-FTD, including in presymptomatic C9orf72 mutation carriers, and accumulates at levels highly correlated with those in CSF. Our findings indicate that loss of TDP-43 cryptic splicing repression occurs early in disease progression, even presymptomatically, and that detection of the HDGFL2 cryptic neoepitope serves as a potential diagnostic biomarker for ALS, which should facilitate patient recruitment and measurement of target engagement in clinical trials.
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Affiliation(s)
- Katherine E Irwin
- Department of Pathology, Johns Hopkins Medicine, Baltimore, MD, USA
- Department of Neuroscience, Johns Hopkins Medicine, Baltimore, MD, USA
| | - Pei Jasin
- Department of Pathology, Johns Hopkins Medicine, Baltimore, MD, USA
| | | | - Irika R Sinha
- Department of Pathology, Johns Hopkins Medicine, Baltimore, MD, USA
- Department of Neuroscience, Johns Hopkins Medicine, Baltimore, MD, USA
| | - Mark A Garret
- Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Boston, MA, USA
| | - Kyra D Bowden
- Department of Pathology, Johns Hopkins Medicine, Baltimore, MD, USA
- Department of Neuroscience, Johns Hopkins Medicine, Baltimore, MD, USA
| | - Koping Chang
- Department of Pathology, Johns Hopkins Medicine, Baltimore, MD, USA
- Department and Graduate Institute of Pathology, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Juan C Troncoso
- Department of Pathology, Johns Hopkins Medicine, Baltimore, MD, USA
- Department of Neurology, Johns Hopkins Medicine, Baltimore, MD, USA
| | - Abhay Moghekar
- Department of Neurology, Johns Hopkins Medicine, Baltimore, MD, USA
| | - Esther S Oh
- Department of Pathology, Johns Hopkins Medicine, Baltimore, MD, USA
- Department of Medicine, Johns Hopkins Medicine, Baltimore, MD, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medicine, Baltimore, MD, USA
| | | | | | - Timothy Miller
- Department of Neurology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - James D Berry
- Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Boston, MA, USA
| | - Bryan J Traynor
- Department of Neurology, Johns Hopkins Medicine, Baltimore, MD, USA
- Neuromuscular Diseases Research Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
- National Institute of Neurological Disorders, National Institutes of Health, Bethesda, MD, USA
- RNA Therapeutics Laboratory, Therapeutics Development Branch, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, USA
| | - Jonathan P Ling
- Department of Pathology, Johns Hopkins Medicine, Baltimore, MD, USA
| | - Philip C Wong
- Department of Pathology, Johns Hopkins Medicine, Baltimore, MD, USA.
- Department of Neuroscience, Johns Hopkins Medicine, Baltimore, MD, USA.
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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: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Yuva-Aydemir Y, Almeida S, Krishnan G, Gendron TF, Gao FB. Transcription elongation factor AFF2/FMR2 regulates expression of expanded GGGGCC repeat-containing C9ORF72 allele in ALS/FTD. Nat Commun 2019; 10:5466. [PMID: 31784536 PMCID: PMC6884579 DOI: 10.1038/s41467-019-13477-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 11/11/2019] [Indexed: 12/18/2022] Open
Abstract
Expanded GGGGCC (G4C2) repeats in C9ORF72 cause amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). How RNAs containing expanded G4C2 repeats are transcribed in human neurons is largely unknown. Here we describe a Drosophila model in which poly(GR) expression in adult neurons causes axonal and locomotor defects and premature death without apparent TDP-43 pathology. In an unbiased genetic screen, partial loss of Lilliputian (Lilli) activity strongly suppresses poly(GR) toxicity by specifically downregulating the transcription of GC-rich sequences in Drosophila. Knockout of AFF2/FMR2 (one of four mammalian homologues of Lilli) with CRISPR-Cas9 decreases the expression of the mutant C9ORF72 allele containing expanded G4C2 repeats and the levels of repeat RNA foci and dipeptide repeat proteins in cortical neurons derived from induced pluripotent stem cells of C9ORF72 patients, resulting in rescue of axonal degeneration and TDP-43 pathology. Thus, AFF2/FMR2 regulates the transcription and toxicity of expanded G4C2 repeats in human C9ORF72-ALS/FTD neurons.
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Affiliation(s)
- Yeliz Yuva-Aydemir
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Sandra Almeida
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
| | - Gopinath Krishnan
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Tania F Gendron
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA
| | - Fen-Biao Gao
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
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