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Cicardi ME, Kankate V, Sriramoji S, Krishnamurthy K, Markandaiah SS, Verdone BM, Girdhar A, Nelson A, Rivas LB, Boehringer A, Haeusler AR, Pasinelli P, Guo L, Trotti D. The nuclear import receptor Kapβ2 modifies neurotoxicity mediated by poly(GR) in C9orf72-linked ALS/FTD. Commun Biol 2024; 7:376. [PMID: 38548902 PMCID: PMC10978903 DOI: 10.1038/s42003-024-06071-2] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 03/19/2024] [Indexed: 04/01/2024] Open
Abstract
Expanded intronic G4C2 repeats in the C9ORF72 gene cause amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). These intronic repeats are translated through a non-AUG-dependent mechanism into five different dipeptide repeat proteins (DPRs), including poly-glycine-arginine (GR), which is aggregation-prone and neurotoxic. Here, we report that Kapβ2 and GR interact, co-aggregating, in cultured neurons in-vitro and CNS tissue in-vivo. Importantly, this interaction significantly decreased the risk of death of cultured GR-expressing neurons. Downregulation of Kapβ2 is detrimental to their survival, whereas increased Kapβ2 levels mitigated GR-mediated neurotoxicity. As expected, GR-expressing neurons displayed TDP-43 nuclear loss. Raising Kapβ2 levels did not restore TDP-43 into the nucleus, nor did alter the dynamic properties of GR aggregates. Overall, our findings support the design of therapeutic strategies aimed at up-regulating Kapβ2 expression levels as a potential new avenue for contrasting neurodegeneration in C9orf72-ALS/FTD.
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Affiliation(s)
- M E Cicardi
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - V Kankate
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - S Sriramoji
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - K Krishnamurthy
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - S S Markandaiah
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - B M Verdone
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - A Girdhar
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - A Nelson
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - L B Rivas
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - A Boehringer
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - A R Haeusler
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - P Pasinelli
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - L Guo
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA, USA.
| | - D Trotti
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA.
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Zhang F, Bischof H, Burgstaller S, Bourgeois BMR, Malli R, Madl T. Genetically encoded fluorescent sensor to monitor intracellular arginine methylation. J Photochem Photobiol B 2024; 252:112867. [PMID: 38368636 DOI: 10.1016/j.jphotobiol.2024.112867] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 02/03/2024] [Accepted: 02/12/2024] [Indexed: 02/20/2024]
Abstract
Arginine methylation (ArgMet), as a post-translational modification, plays crucial roles in RNA processing, transcriptional regulation, signal transduction, DNA repair, apoptosis and liquid-liquid phase separation (LLPS). Since arginine methylation is associated with cancer pathogenesis and progression, protein arginine methyltransferases have gained interest as targets for anti-cancer therapy. Despite considerable process made to elucidate (patho)physiological mechanisms regulated by arginine methylation, there remains a lack of tools to visualize arginine methylation with high spatiotemporal resolution in live cells. To address this unmet need, we generated an ArgMet-sensitive genetically encoded, Förster resonance energy transfer-(FRET) based biosensor, called GEMS, capable of quantitative real-time monitoring of ArgMet dynamics. We optimized these biosensors by using different ArgMet-binding domains, arginine-glycine-rich regions and adjusting the linkers within the biosensors to improve their performance. Using a set of mammalian cell lines and modulators, we demonstrated the applicability of GEMS for monitoring changes in arginine methylation with single-cell and temporal resolution. The GEMS can facilitate the in vitro screening to find potential protein arginine methyltransferase inhibitors and will contribute to a better understanding of the regulation of ArgMet related to differentiation, development and disease.
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Affiliation(s)
- Fangrong Zhang
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou 350122, China; Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Helmut Bischof
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Sandra Burgstaller
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Benjamin M R Bourgeois
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; Otto Loewi Research Center, Medicinal Chemistry, Medical University of Graz, 8010 Graz, Austria
| | - Roland Malli
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria
| | - Tobias Madl
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; Otto Loewi Research Center, Medicinal Chemistry, Medical University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria.
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3
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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] [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: 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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4
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Liu Y, Feng W, Wang Y, Wu B. Crosstalk between protein post-translational modifications and phase separation. Cell Commun Signal 2024; 22:110. [PMID: 38347544 PMCID: PMC10860296 DOI: 10.1186/s12964-023-01380-1] [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: 09/15/2023] [Accepted: 11/02/2023] [Indexed: 02/15/2024] Open
Abstract
The phenomenon of phase separation is quite common in cells, and it is involved in multiple processes of life activities. However, the current research on the correlation between protein modifications and phase separation and the interference with the tendency of phase separation has some limitations. Here we focus on several post-translational modifications of proteins, including protein phosphorylation modification at multiple sites, methylation modification, acetylation modification, ubiquitination modification, SUMOylation modification, etc., which regulate the formation of phase separation and the stability of phase separation structure through multivalent interactions. This regulatory role is closely related to the development of neurodegenerative diseases, tumors, viral infections, and other diseases, and also plays essential functions in environmental stress, DNA damage repair, transcriptional regulation, signal transduction, and cell homeostasis of living organisms, which provides an idea to explore the interaction between novel protein post-translational modifications and phase separation. Video Abstract.
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Affiliation(s)
- Yang Liu
- Jinan Central Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Wenjuan Feng
- Department of Reproductive Medicine, Central Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Yunshan Wang
- Jinan Central Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.
- Basic Medical Research Center, Central Hospital Affiliated to Shandong First Medical University, Jinan, China.
| | - Bin Wu
- Jinan Central Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.
- Department of Reproductive Medicine, Central Hospital Affiliated to Shandong First Medical University, Jinan, China.
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5
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Abstract
Biomolecular condensates are reversible compartments that form through a process called phase separation. Post-translational modifications like ADP-ribosylation can nucleate the formation of these condensates by accelerating the self-association of proteins. Poly(ADP-ribose) (PAR) chains are remarkably transient modifications with turnover rates on the order of minutes, yet they can be required for the formation of granules in response to oxidative stress, DNA damage, and other stimuli. Moreover, accumulation of PAR is linked with adverse phase transitions in neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. In this review, we provide a primer on how PAR is synthesized and regulated, the diverse structures and chemistries of ADP-ribosylation modifications, and protein-PAR interactions. We review substantial progress in recent efforts to determine the molecular mechanism of PAR-mediated phase separation, and we further delineate how inhibitors of PAR polymerases may be effective treatments for neurodegenerative pathologies. Finally, we highlight the need for rigorous biochemical interrogation of ADP-ribosylation in vivo and in vitro to clarify the exact pathway from PARylation to condensate formation.
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Affiliation(s)
- Kevin Rhine
- Program in Cell, Molecular, Developmental Biology, and Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Hana M Odeh
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, United States
| | - James Shorter
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, United States
| | - Sua Myong
- Program in Cell, Molecular, Developmental Biology, and Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
- Physics Frontier Center (Center for the Physics of Living Cells), University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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Abstract
A hexanucleotide repeat expansion in the C9ORF72 gene is the most common genetic alteration associated with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). These neurodegenerative diseases share genetic, clinical and pathological features. The mutation in C9ORF72 appears to drive pathogenesis through a combination of loss of C9ORF72 normal function and gain of toxic effects due to the repeat expansion, which result in aggregation prone expanded RNAs and dipeptide repeat (DPR) proteins. Studies in cellular and animal models indicate that the DPR proteins are the more toxic species. Thus, a large body of research has focused on identifying the cellular pathways most directly impacted by these toxic proteins, with the goal of characterizing disease pathogenesis and nominating potential targets for therapeutic development. The preventative block of the production of the toxic proteins before they can cause harm is a second strategy of intense focus. Despite the considerable amount of effort dedicated to this prophylactic approach, it is still unclear how the DPR proteins are synthesized from RNAs harboring repeat expansions. In this review, we summarize our current knowledge of the specific protein translation mechanisms shown to account for the synthesis of DPR proteins. We will then discuss how enhanced understanding of the composition of these toxic effectors could help in refining disease mechanisms, and paving the way to identify and design effective prophylactic therapies for C9ORF72 ALS-FTD.
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Affiliation(s)
- Heleen M Van't Spijker
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Sandra Almeida
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA.
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7
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Boeynaems S, Ma XR, Yeong V, Ginell GM, Chen JH, Blum JA, Nakayama L, Sanyal A, Briner A, Haver DV, Pauwels J, Ekman A, Schmidt HB, Sundararajan K, Porta L, Lasker K, Larabell C, Hayashi MAF, Kundaje A, Impens F, Obermeyer A, Holehouse AS, Gitler AD. Aberrant phase separation is a common killing strategy of positively charged peptides in biology and human disease. bioRxiv 2023:2023.03.09.531820. [PMID: 36945394 PMCID: PMC10028949 DOI: 10.1101/2023.03.09.531820] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Positively charged repeat peptides are emerging as key players in neurodegenerative diseases. These peptides can perturb diverse cellular pathways but a unifying framework for how such promiscuous toxicity arises has remained elusive. We used mass-spectrometry-based proteomics to define the protein targets of these neurotoxic peptides and found that they all share similar sequence features that drive their aberrant condensation with these positively charged peptides. We trained a machine learning algorithm to detect such sequence features and unexpectedly discovered that this mode of toxicity is not limited to human repeat expansion disorders but has evolved countless times across the tree of life in the form of cationic antimicrobial and venom peptides. We demonstrate that an excess in positive charge is necessary and sufficient for this killer activity, which we name 'polycation poisoning'. These findings reveal an ancient and conserved mechanism and inform ways to leverage its design rules for new generations of bioactive peptides.
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Affiliation(s)
- Steven Boeynaems
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030, USA
- Therapeutic Innovation Center (THINC), Baylor College of Medicine, Houston, TX 77030, USA
- Center for Alzheimer’s and Neurodegenerative Diseases (CAND), Texas Children’s Hospital, Houston, TX 77030, USA
- Dan L Duncan Comprehensive Cancer Center (DLDCCC), Baylor College of Medicine, Houston, TX 77030, USA
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - X. Rosa Ma
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Vivian Yeong
- Department of Chemical Engineering, Columbia University, New York, NY, 10027, USA
| | - Garrett M. Ginell
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
- Center for Biomolecular Condensates, Washington University in St Louis, St. Louis, MO 63130, USA
| | - Jian-Hua Chen
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Anatomy, University of California, San Francisco, CA 94143, USA
| | - Jacob A. Blum
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lisa Nakayama
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Anushka Sanyal
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Adam Briner
- Clem Jones Centre for Ageing Dementia Research (CJCADR), Queensland Brain Institute (QBI), The University of Queensland, Brisbane, QLD 4072, Australia
| | - Delphi Van Haver
- VIB-UGent Center for Medical Biotechnology, 9000 Gent, Belgium
- VIB Proteomics Core, 9000 Gent, Belgium
- Department of Biochemistry, Ghent University, 9000 Gent, Belgium
| | - Jarne Pauwels
- VIB-UGent Center for Medical Biotechnology, 9000 Gent, Belgium
- VIB Proteomics Core, 9000 Gent, Belgium
- Department of Biochemistry, Ghent University, 9000 Gent, Belgium
| | - Axel Ekman
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Anatomy, University of California, San Francisco, CA 94143, USA
| | - H. Broder Schmidt
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kousik Sundararajan
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lucas Porta
- Department of Pharmacology, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), Sao Paulo, Brazil
| | - Keren Lasker
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Carolyn Larabell
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Anatomy, University of California, San Francisco, CA 94143, USA
| | - Mirian A. F. Hayashi
- Department of Pharmacology, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), Sao Paulo, Brazil
| | - Anshul Kundaje
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Computer Science, Stanford University, Stanford, CA 94305, USA
| | - Francis Impens
- VIB-UGent Center for Medical Biotechnology, 9000 Gent, Belgium
- VIB Proteomics Core, 9000 Gent, Belgium
- Department of Biochemistry, Ghent University, 9000 Gent, Belgium
| | - Allie Obermeyer
- Department of Chemical Engineering, Columbia University, New York, NY, 10027, USA
| | - Alex S. Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
- Center for Biomolecular Condensates, Washington University in St Louis, St. Louis, MO 63130, USA
| | - Aaron D. Gitler
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
- Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
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Zhang F, Rakhimbekova A, Lashley T, Madl T. Brain regions show different metabolic and protein arginine methylation phenotypes in frontotemporal dementias and Alzheimer's disease. Prog Neurobiol 2023; 221:102400. [PMID: 36581185 DOI: 10.1016/j.pneurobio.2022.102400] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 11/05/2022] [Accepted: 12/19/2022] [Indexed: 12/27/2022]
Abstract
Frontotemporal dementia (FTD) is a heterogeneous neurodegenerative disease with multiple histopathological subtypes. FTD patients share similar symptoms with Alzheimer's disease (AD). Hence, FTD patients are commonly misdiagnosed as AD, despite the consensus clinical diagnostic criteria. It is therefore of great clinical need to identify a biomarker that can distinguish FTD from AD and control individuals, and potentially further differentiate between FTD pathological subtypes. We conducted a metabolomic analysis on post-mortem human brain tissue from three regions: cerebellum, frontal cortex and occipital cortex from control, FTLD-TDP type A, type A-C9, type C and AD. Our results indicate that the brain subdivisions responsible for different functions show different metabolic patterns. We further explored the region-specific metabolic characteristics of different FTD subtypes and AD patients. Different FTD subtypes and AD share similar metabolic phenotypes in the cerebellum, but AD exhibited distinct metabolic patterns in the frontal and occipital regions compared to FTD. The identified brain region-specific metabolite biomarkers could provide a tool for distinguishing different FTD subtypes and AD and provide the first insights into the metabolic changes of FTLD-TDP type A, type A-C9, type C and AD in different regions of the brain. The importance of protein arginine methylation in neurodegenerative disease has come to light, so we investigated whether the arginine methylation level contributes to disease pathogenesis. Our findings provide new insights into the relationship between arginine methylation and metabolic changes in FTD subtypes and AD that could be further explored, to study the molecular mechanism of pathogenesis.
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Affiliation(s)
- Fangrong Zhang
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China; Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Research Unit Integrative Structural Biology, Medical University of Graz, 8010 Graz, Austria.
| | - Anastasia Rakhimbekova
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Research Unit Integrative Structural Biology, Medical University of Graz, 8010 Graz, Austria.
| | - Tammaryn Lashley
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK; Queen Square Brain Bank for Neurological Diseases, UCL Queen Square Institute of Neurology, London, UK.
| | - Tobias Madl
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Research Unit Integrative Structural Biology, Medical University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria.
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Dane TL, Gill AL, Vieira FG, Denton KR. Reduced C9orf72 expression exacerbates polyGR toxicity in patient iPSC-derived motor neurons and a Type I protein arginine methyltransferase inhibitor reduces that toxicity. Front Cell Neurosci 2023; 17:1134090. [PMID: 37138766 PMCID: PMC10149854 DOI: 10.3389/fncel.2023.1134090] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 03/27/2023] [Indexed: 05/05/2023] Open
Abstract
Introduction Intronic repeat expansions in the C9orf72 gene are the most frequent known single genetic causes of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). These repeat expansions are believed to result in both loss-of-function and toxic gain-of-function. Gain-of-function results in the production of toxic arginine-rich dipeptide repeat proteins (DPRs), namely polyGR and polyPR. Small-molecule inhibition of Type I protein arginine methyltransferases (PRMTs) has been shown to protect against toxicity resulting from polyGR and polyPR challenge in NSC-34 cells and primary mouse-derived spinal neurons, but the effect in human motor neurons (MNs) has not yet been explored. Methods To study this, we generated a panel of C9orf72 homozygous and hemizygous knockout iPSCs to examine the contribution of C9orf72 loss-of-function toward disease pathogenesis. We differentiated these iPSCs into spinal motor neurons (sMNs). Results We found that reduced levels of C9orf72 exacerbate polyGR15 toxicity in a dose-dependent manner. Type I PRMT inhibition was able to partially rescue polyGR15 toxicity in both wild-type and C9orf72-expanded sMNs. Discussion This study explores the interplay of loss-of-function and gain-of-function toxicity in C9orf72 ALS. It also implicates type I PRMT inhibitors as a possible modulator of polyGR toxicity.
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Kanekura K, Kuroda M. How can we interpret the relationship between liquid-liquid phase separation and amyotrophic lateral sclerosis? J Transl Med 2022; 102:912-918. [PMID: 36775420 DOI: 10.1038/s41374-022-00791-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 04/12/2022] [Indexed: 01/08/2023] Open
Abstract
One of the critical definitions of neurodegenerative diseases is the formation of insoluble intracellular inclusion body. These inclusions are found in various neurodegenerative diseases such as Alzheimer's disease, amyotrophic lateral sclerosis (ALS), Huntington's disease, Parkinson's disease, and frontotemporal dementia (FTD). Each inclusion body contains disease-specific proteins and is also resistant to common detergent treatments. These aggregates are generally ubiquitinated and thus recognized as misfolded by the organism. They are observed in residual neurons at the affected sites in each disease, suggesting a contribution to disease pathogenesis. The molecular mechanisms for the formation of these inclusion bodies remain unclear. Some proteins, such as superoxide dismutase 1 (SOD1) mutant that causes familial ALS, are highly aggregative due to altered folding caused by point mutations. Still, the aggregates observed in neurodegenerative diseases contain wild-type proteins. In recent years, it has been reported that the proteins responsible for neurodegenerative diseases undergo liquid-liquid phase separation (LLPS). In particular, the ALS/FTD causative proteins such as TAR DNA-binding protein 43 kDa (TDP-43) and fused-in-sarcoma (FUS) undergo LLPS. LLPS increases the local concentration of these proteins, and these proteins eventually change their phase from liquid to solid (liquid-solid phase transition) due to abnormal folding during repetitive separation cycles into two phases and recovery to one phase. In addition to the inclusion body formation, sequestration of essential proteins into the LLPS droplets or changes in the LLPS status can directly impair neural functions and cause diseases. In this review, we will discuss the relationship between the LLPS observed in ALS causative proteins and the pathogenesis of the disease and outline potential therapeutic approaches.
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Affiliation(s)
- Kohsuke Kanekura
- Department of Molecular Pathology, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo, 160-8402, Japan.
| | - Masahiko Kuroda
- Department of Molecular Pathology, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo, 160-8402, Japan
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11
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Houghton OH, Mizielinska S, Gomez-Suaga P. The Interplay Between Autophagy and RNA Homeostasis: Implications for Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Front Cell Dev Biol 2022; 10:838402. [PMID: 35573690 PMCID: PMC9096704 DOI: 10.3389/fcell.2022.838402] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 04/14/2022] [Indexed: 01/18/2023] Open
Abstract
Amyotrophic lateral sclerosis and frontotemporal dementia are neurodegenerative disorders that lie on a disease spectrum, sharing genetic causes and pathology, and both without effective therapeutics. Two pathways that have been shown to play major roles in disease pathogenesis are autophagy and RNA homeostasis. Intriguingly, there is an increasing body of evidence suggesting a critical interplay between these pathways. Autophagy is a multi-stage process for bulk and selective clearance of malfunctional cellular components, with many layers of regulation. Although the majority of autophagy research focuses on protein degradation, it can also mediate RNA catabolism. ALS/FTD-associated proteins are involved in many stages of autophagy and autophagy-mediated RNA degradation, particularly converging on the clearance of persistent pathological stress granules. In this review, we will summarise the progress in understanding the autophagy-RNA homeostasis interplay and how that knowledge contributes to our understanding of the pathobiology of ALS/FTD.
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Affiliation(s)
- O H Houghton
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom.,UK Dementia Research Institute at King's College London, London, United Kingdom
| | - S Mizielinska
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom.,UK Dementia Research Institute at King's College London, London, United Kingdom
| | - P Gomez-Suaga
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom.,Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Cáceres, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Instituto Universitario de Investigación Biosanitaria de Extremadura (INUBE), Cáceres, Spain
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12
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Li J, Zhang M, Ma W, Yang B, Lu H, Zhou F, Zhang L. Post-translational modifications in liquid-liquid phase separation: a comprehensive review. Mol Biomed 2022; 3:13. [PMID: 35543798 PMCID: PMC9092326 DOI: 10.1186/s43556-022-00075-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/25/2022] [Indexed: 11/23/2022] Open
Abstract
Liquid-liquid phase separation (LLPS) has received significant attention in recent biological studies. It refers to a phenomenon that biomolecule exceeds the solubility, condensates and separates itself from solution in liquid like droplets formation. Our understanding of it has also changed from memebraneless organelles to compartmentalization, muti-functional crucibles, and reaction regulators. Although this phenomenon has been employed for a variety of biological processes, recent studies mainly focus on its physiological significance, and the comprehensive research of the underlying physical mechanism is limited. The characteristics of side chains of amino acids and the interaction tendency of proteins function importantly in regulating LLPS thus should be pay more attention on. In addition, the importance of post-translational modifications (PTMs) has been underestimated, despite their abundance and crucial functions in maintaining the electrostatic balance. In this review, we first introduce the driving forces and protein secondary structures involved in LLPS and their different physical functions in cell life processes. Subsequently, we summarize the existing reports on PTM regulation related to LLPS and analyze the underlying basic principles, hoping to find some common relations between LLPS and PTM. Finally, we speculate several unreported PTMs that may have a significant impact on phase separation basing on the findings.
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Affiliation(s)
- Jingxian Li
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, China
| | - Mengdi Zhang
- School of Medicine, Zhejiang University City College, Hangzhou, 310015, Zhejiang, China
| | - Weirui Ma
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, China
| | - Bing Yang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, China
| | - Huasong Lu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, China
| | - Fangfang Zhou
- Institutes of Biology and Medical Science, Soochow University, Suzhou, 215123, P. R. China.
| | - Long Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, China.
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13
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Riemslagh FW, Verhagen RFM, van der Toorn EC, Smits DJ, Quint WH, van der Linde HC, van Ham TJ, Willemsen R. Reduction of oxidative stress suppresses poly-GR-mediated toxicity in zebrafish embryos. Dis Model Mech 2021; 14:272601. [PMID: 34693978 PMCID: PMC8649169 DOI: 10.1242/dmm.049092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Accepted: 10/13/2021] [Indexed: 12/17/2022] Open
Abstract
The hexanucleotide (G4C2)-repeat expansion in the C9ORF72 gene is the most common pathogenic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). This repeat expansion can be translated into dipeptide repeat proteins (DPRs), and distribution of the poly-GR DPR correlates with neurodegeneration in postmortem C9FTD/ALS brains. Here, we assessed poly-GR toxicity in zebrafish embryos, using an annexin A5-based fluorescent transgenic line (secA5) that allows for detection and quantification of apoptosis in vivo. Microinjection of RNA encoding poly-GR into fertilized oocytes evoked apoptosis in the brain and abnormal motor neuron morphology in the trunk of 1-4-days postfertilization embryos. Poly-GR can be specifically detected in protein homogenates from injected zebrafish and in the frontal cortexes of C9FTD/ALS cases. Poly-GR expression further elevated MitoSOX levels in zebrafish embryos, indicating oxidative stress. Inhibition of reactive oxygen species using Trolox showed full suppression of poly-GR toxicity. Our study indicates that poly-GR can exert its toxicity via oxidative stress. This zebrafish model can be used to find suppressors of poly-GR toxicity and identify its molecular targets underlying neurodegeneration observed in C9FTD/ALS. Summary: Toxicity of C9ALS/FTD poly-GR in zebrafish embryos is suppressed by Trolox, and poly-GR can be detected and quantified in zebrafish model protein homogenates, and in the frontal cortex of C9FTD/ALS cases.
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Affiliation(s)
- Fréderike W Riemslagh
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, 3000 CA, Rotterdam, The Netherlands
| | - Rob F M Verhagen
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, 3000 CA, Rotterdam, The Netherlands
| | - Esmay C van der Toorn
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, 3000 CA, Rotterdam, The Netherlands
| | - Daphne J Smits
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, 3000 CA, Rotterdam, The Netherlands
| | - Wim H Quint
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, 3000 CA, Rotterdam, The Netherlands
| | - Herma C van der Linde
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, 3000 CA, Rotterdam, The Netherlands
| | - Tjakko J van Ham
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, 3000 CA, Rotterdam, The Netherlands
| | - Rob Willemsen
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, 3000 CA, Rotterdam, The Netherlands
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14
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Nanaura H, Kawamukai H, Fujiwara A, Uehara T, Aiba Y, Nakanishi M, Shiota T, Hibino M, Wiriyasermkul P, Kikuchi S, Nagata R, Matsubayashi M, Shinkai Y, Niwa T, Mannen T, Morikawa N, Iguchi N, Kiriyama T, Morishima K, Inoue R, Sugiyama M, Oda T, Kodera N, Toma-Fukai S, Sato M, Taguchi H, Nagamori S, Shoji O, Ishimori K, Matsumura H, Sugie K, Saio T, Yoshizawa T, Mori E. C9orf72-derived arginine-rich poly-dipeptides impede phase modifiers. Nat Commun 2021; 12:5301. [PMID: 34489423 DOI: 10.1038/s41467-021-25560-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 08/16/2021] [Indexed: 01/13/2023] Open
Abstract
Nuclear import receptors (NIRs) not only transport RNA-binding proteins (RBPs) but also modify phase transitions of RBPs by recognizing nuclear localization signals (NLSs). Toxic arginine-rich poly-dipeptides from C9orf72 interact with NIRs and cause nucleocytoplasmic transport deficit. However, the molecular basis for the toxicity of arginine-rich poly-dipeptides toward NIRs function as phase modifiers of RBPs remains unidentified. Here we show that arginine-rich poly-dipeptides impede the ability of NIRs to modify phase transitions of RBPs. Isothermal titration calorimetry and size-exclusion chromatography revealed that proline:arginine (PR) poly-dipeptides tightly bind karyopherin-β2 (Kapβ2) at 1:1 ratio. The nuclear magnetic resonances of Kapβ2 perturbed by PR poly-dipeptides partially overlapped with those perturbed by the designed NLS peptide, suggesting that PR poly-dipeptides target the NLS binding site of Kapβ2. The findings offer mechanistic insights into how phase transitions of RBPs are disabled in C9orf72-related neurodegeneration. Nuclear import receptors (NIRs) regulate self-association of RNA-binding proteins as phase modifiers, while C9orf72-derived arginine-rich polydipeptides lead to aberrant phase transitions. Here the authors show in molecular basis how arginine-rich poly-dipeptides impede the ability of NIRs, particularly Kapβ2.
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15
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Odeh HM, Shorter J. Arginine-rich dipeptide-repeat proteins as phase disruptors in C9-ALS/FTD. Emerg Top Life Sci 2020; 4:293-305. [PMID: 32639008 DOI: 10.1042/ETLS20190167] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/15/2020] [Accepted: 06/17/2020] [Indexed: 12/11/2022]
Abstract
A hexanucleotide repeat expansion GGGGCC (G4C2) within chromosome 9 open reading frame 72 (C9orf72) is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia (C9-ALS/FTD). This seminal realization has rapidly focused our attention to the non-canonical translation (RAN translation) of the repeat expansion, which yields dipeptide-repeat protein products (DPRs). The mechanisms by which DPRs might contribute to C9-ALS/FTD are widely studied. Arginine-rich DPRs (R-DPRs) are the most toxic of the five different DPRs produced in neurons, but how do R-DPRs promote C9-ALS/FTD pathogenesis? Proteomic analyses have uncovered potential pathways to explore. For example, the vast majority of the R-DPR interactome is comprised of disease-linked RNA-binding proteins (RBPs) with low-complexity domains (LCDs), strongly suggesting a link between R-DPRs and aberrations in liquid-liquid phase separation (LLPS). In this review, we showcase several potential mechanisms by which R-DPRs disrupt various phase-separated compartments to elicit deleterious neurodegeneration. We also discuss potential therapeutic strategies to counter R-DPR toxicity in C9-ALS/FTD.
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16
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Mori K, Gotoh S, Yamashita T, Uozumi R, Kawabe Y, Tagami S, Kamp F, Nuscher B, Edbauer D, Haass C, Nagai Y, Ikeda M. 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 DOI: 10.1016/j.jbc.2021.101120] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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17
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Zhang F, Kerbl-Knapp J, Rodriguez Colman MJ, Meinitzer A, Macher T, Vujić N, Fasching S, Jany-Luig E, Korbelius M, Kuentzel KB, Mack M, Akhmetshina A, Pirchheim A, Paar M, Rinner B, Hörl G, Steyrer E, Stelzl U, Burgering B, Eisenberg T, Pertschy B, Kratky D, Madl T. Global analysis of protein arginine methylation. Cell Rep Methods 2021; 1:100016. [PMID: 35475236 PMCID: PMC9017121 DOI: 10.1016/j.crmeth.2021.100016] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [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] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 04/02/2021] [Accepted: 05/12/2021] [Indexed: 12/25/2022]
Abstract
Quantitative information about the levels and dynamics of post-translational modifications (PTMs) is critical for an understanding of cellular functions. Protein arginine methylation (ArgMet) is an important subclass of PTMs and is involved in a plethora of (patho)physiological processes. However, because of the lack of methods for global analysis of ArgMet, the link between ArgMet levels, dynamics, and (patho)physiology remains largely unknown. We utilized the high sensitivity and robustness of nuclear magnetic resonance (NMR) spectroscopy to develop a general method for the quantification of global protein ArgMet. Our NMR-based approach enables the detection of protein ArgMet in purified proteins, cells, organoids, and mouse tissues. We demonstrate that the process of ArgMet is a highly prevalent PTM and can be modulated by small-molecule inhibitors and metabolites and changes in cancer and during aging. Thus, our approach enables us to address a wide range of biological questions related to ArgMet in health and disease.
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Affiliation(s)
- Fangrong Zhang
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Jakob Kerbl-Knapp
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Maria J. Rodriguez Colman
- Oncode Institute and Department of Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Andreas Meinitzer
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, 8010 Graz, Austria
| | - Therese Macher
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Nemanja Vujić
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
| | - Sandra Fasching
- Institute of Pharmaceutical Sciences, University of Graz, 8010 Graz, Austria
| | - Evelyne Jany-Luig
- Institute of Pharmaceutical Sciences, University of Graz, 8010 Graz, Austria
| | - Melanie Korbelius
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Katharina B. Kuentzel
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Maximilian Mack
- BioTechMed-Graz, 8010 Graz, Austria
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
| | - Alena Akhmetshina
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Anita Pirchheim
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Margret Paar
- Otto-Loewi Research Center, Physiological Chemistry, Medical University of Graz, 8010 Graz, Austria
| | - Beate Rinner
- Division of Biomedical Research, Medical University of Graz, 8036 Graz, Austria
| | - Gerd Hörl
- Otto-Loewi Research Center, Physiological Chemistry, Medical University of Graz, 8010 Graz, Austria
| | - Ernst Steyrer
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Ulrich Stelzl
- BioTechMed-Graz, 8010 Graz, Austria
- Institute of Pharmaceutical Sciences, University of Graz, 8010 Graz, Austria
| | - Boudewijn Burgering
- Oncode Institute and Department of Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Tobias Eisenberg
- BioTechMed-Graz, 8010 Graz, Austria
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
- Field of Excellence BioHealth – University of Graz, Graz, Austria
| | - Brigitte Pertschy
- BioTechMed-Graz, 8010 Graz, Austria
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
- Field of Excellence BioHealth – University of Graz, Graz, Austria
| | - Dagmar Kratky
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
| | - Tobias Madl
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
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18
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Solomon DA, Smikle R, Reid MJ, Mizielinska S. Altered Phase Separation and Cellular Impact in C9orf72-Linked ALS/FTD. Front Cell Neurosci 2021; 15:664151. [PMID: 33967699 PMCID: PMC8096919 DOI: 10.3389/fncel.2021.664151] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/19/2021] [Indexed: 12/21/2022] Open
Abstract
Since the discovery of the C9orf72 repeat expansion mutation as causative for chromosome 9-linked amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) in 2011, a multitude of cellular pathways have been implicated. However, evidence has also been accumulating for a key mechanism of cellular compartmentalization—phase separation. Liquid-liquid phase separation (LLPS) is fundamental for the formation of membraneless organelles including stress granules, the nucleolus, Cajal bodies, nuclear speckles and the central channel of the nuclear pore. Evidence has now accumulated showing that the formation and function of these membraneless organelles is impaired by both the toxic arginine rich dipeptide repeat proteins (DPRs), translated from the C9orf72 repeat RNA transcript, and the repeat RNA itself. Both the arginine rich DPRs and repeat RNA themselves undergo phase separation and disrupt the physiological phase separation of proteins involved in the formation of these liquid-like organelles. Hence abnormal phase separation may explain a number of pathological cellular phenomena associated with C9orf72-ALS/FTD. In this review article, we will discuss the principles of phase separation, phase separation of the DPRs and repeat RNA themselves and how they perturb LLPS associated with membraneless organelles and the functional consequences of this. We will then discuss how phase separation may impact the major pathological feature of C9orf72-ALS/FTD, TDP-43 proteinopathy, and how LLPS may be targeted therapeutically in disease.
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Affiliation(s)
- Daniel A Solomon
- UK Dementia Research Institute at King's College London, London, United Kingdom.,Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
| | - Rebekah Smikle
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
| | - Matthew J Reid
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
| | - Sarah Mizielinska
- UK Dementia Research Institute at King's College London, London, United Kingdom.,Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
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19
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Gill AL, Premasiri AS, Vieira FG. Hypothesis and Theory: Roles of Arginine Methylation in C9orf72-Mediated ALS and FTD. Front Cell Neurosci 2021; 15:633668. [PMID: 33833668 PMCID: PMC8021787 DOI: 10.3389/fncel.2021.633668] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/09/2021] [Indexed: 12/11/2022] Open
Abstract
Hexanucleotide repeat expansion (G4C2n) mutations in the gene C9ORF72 account for approximately 30% of familial cases of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), as well as approximately 7% of sporadic cases of ALS. G4C2n mutations are known to result in the production of five species of dipeptide repeat proteins (DRPs) through non-canonical translation processes. Arginine-enriched dipeptide repeat proteins, glycine-arginine (polyGR), and proline-arginine (polyPR) have been demonstrated to be cytotoxic and deleterious in multiple experimental systems. Recently, we and others have implicated methylation of polyGR/polyPR arginine residues in disease processes related to G4C2n mutation-mediated neurodegeneration. We previously reported that inhibition of asymmetric dimethylation (ADMe) of arginine residues is protective in cell-based models of polyGR/polyPR cytotoxicity. These results are consistent with the idea that PRMT-mediated arginine methylation in the context of polyGR/polyPR exposure is harmful. However, it remains unclear why. Here we discuss the influence of arginine methylation on diverse cellular processes including liquid-liquid phase separation, chromatin remodeling, transcription, RNA processing, and RNA-binding protein localization, and we consider how methylation of polyGR/polyPR may disrupt processes essential for normal cellular function and survival.
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Affiliation(s)
- Anna L Gill
- ALS Therapy Development Institute, Cambridge, MA, United States
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20
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Vöglein J, Kostova I, Arzberger T, Roeber S, Schmitz P, Simons M, Ruf V, Windl O, Herms J, Dieterich M, Danek A, Höglinger GU, Giese A, Levin J. First symptom guides diagnosis and prognosis in neurodegenerative diseases-a retrospective study of autopsy proven cases. Eur J Neurol 2021; 28:1801-1811. [PMID: 33662165 DOI: 10.1111/ene.14800] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 03/01/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND PURPOSE Clinical diagnostic criteria for neurodegenerative diseases have been framed based on clinical phenomenology. However, systematic knowledge about the first reported clinical symptoms in neurodegenerative diseases is lacking. Therefore, the aim was to determine the prevalence and clinical implications of the first clinical symptom (FS) as assessed by medical history in neuropathologically proven neurodegenerative diseases. METHODS Neuropathological diagnoses from the Neurobiobank Munich, Germany, were matched with clinical records for analyses of the diagnostic and prognostic values of FSs. RESULTS In all, 301 patients with the neuropathological diagnoses Alzheimer disease (AD), progressive supranuclear palsy (PSP), frontotemporal lobar degeneration (FTLD), Lewy body disease (LBD) including the neuropathologically indistinguishable clinical phenotypes Parkinson disease and dementia with Lewy bodies, multiple system atrophy (MSA) and corticobasal degeneration (CBD) were studied. Memory disturbance was the most common FS in AD (34%), FTLD (19%) and LBD (26%), gait disturbance in PSP (35%) and MSA (27%) and aphasia and personality changes in CBD (20%, respectively). In a model adjusting for prevalence in the general population, AD was predicted by memory disturbance in 79.0%, aphasia in 97.2%, personality changes in 96.0% and by cognitive disturbance in 99.0%. Gait disturbance and tremor predicted LBD in 54.6% and 97.3%, coordination disturbance MSA in 59.4% and dysarthria FTLD in 73.0%. Cognitive FSs were associated with longer survival in AD (12.0 vs. 5.3 years; p < 0.001) and FTLD (8.2 vs. 4.1 years; p = 0.005) and motor FSs with shorter survival in PSP (7.2 vs. 9.7; p = 0.048). CONCLUSIONS Assessing FSs in neurodegenerative diseases may be beneficial for accuracy of diagnosis and prognosis and thereby may improve clinical care and precision of study recruitment.
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Affiliation(s)
- Jonathan Vöglein
- Department of Neurology, Ludwig-Maximilians-Universität München, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Irena Kostova
- Department of Neurology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Thomas Arzberger
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Center for Neuropathology and Prion Research, Ludwig-Maximilians-Universität München, Munich, Germany.,Department for Psychiatry and Psychotherapy, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Sigrun Roeber
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Peer Schmitz
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Mikael Simons
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,Department of Neurology, Technical University of Munich, Munich, Germany
| | - Viktoria Ruf
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Otto Windl
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Center for Neuropathology and Prion Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Jochen Herms
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Center for Neuropathology and Prion Research, Ludwig-Maximilians-Universität München, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Marianne Dieterich
- Department of Neurology, Ludwig-Maximilians-Universität München, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,German Center for Vertigo and Balance Disorders, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Adrian Danek
- Department of Neurology, Ludwig-Maximilians-Universität München, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Günter U Höglinger
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,Department of Neurology, Technical University of Munich, Munich, Germany.,Department of Neurology, Hannover Medical School, Hannover, Germany
| | - Armin Giese
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Johannes Levin
- Department of Neurology, Ludwig-Maximilians-Universität München, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
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21
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Hastings RL, Boeynaems S. Designer Condensates: A Toolkit for the Biomolecular Architect. J Mol Biol 2021; 433:166837. [PMID: 33539874 DOI: 10.1016/j.jmb.2021.166837] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 01/06/2021] [Accepted: 01/16/2021] [Indexed: 12/19/2022]
Abstract
Protein phase separation has emerged as a novel paradigm to explain the biogenesis of membraneless organelles and other so-called biomolecular condensates. While the implication of this physical phenomenon within cell biology is providing us with novel ways for understanding how cells compartmentalize biochemical reactions and encode function in such liquid-like assemblies, the newfound appreciation of this process also provides immense opportunities for designing and sculpting biological matter. Here, we propose that understanding the cell's instruction manual of phase separation will enable bioengineers to begin creating novel functionalized biological materials and unprecedented tools for synthetic biology. We present FASE as the synthesis of the existing sticker-spacer framework, which explains the physical driving forces underlying phase separation, with quintessential principles of Scandinavian design. FASE serves both as a designer condensates catalogue and construction manual for the aspiring (membraneless) biomolecular architect. Our approach aims to inspire a new generation of bioengineers to rethink phase separation as an opportunity for creating reactive biomaterials with unconventional properties and to encode novel biological function in living systems. Although still in its infancy, several studies highlight how designer condensates have immediate and widespread potential applications in industry and medicine.
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Affiliation(s)
- Renee L Hastings
- Program in Biophysics, Stanford University, Stanford, CA 94305, USA
| | - Steven Boeynaems
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA.
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22
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Riemslagh FW, van der Toorn EC, Verhagen RFM, Maas A, Bosman LWJ, Hukema RK, Willemsen R. Inducible expression of human C9ORF72 36x G 4C 2 hexanucleotide repeats is sufficient to cause RAN translation and rapid muscular atrophy in mice. Dis Model Mech 2021; 14:dmm.044842. [PMID: 33431483 PMCID: PMC7903916 DOI: 10.1242/dmm.044842] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 12/17/2020] [Indexed: 12/29/2022] Open
Abstract
The hexanucleotide G4C2 repeat expansion in the first intron of the C9ORF72 gene explains the majority of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) cases. Numerous studies have indicated the toxicity of dipeptide repeats (DPRs) which are produced via repeat-associated non-AUG (RAN) translation from the repeat expansion and accumulate in the brain of C9FTD/ALS patients. Mouse models expressing the human C9ORF72 repeat and/or DPRs show variable pathological, functional, and behavioral characteristics of FTD and ALS. Here, we report a new Tet-on inducible mouse model that expresses 36x pure G4C2 repeats with 100bp upstream and downstream human flanking regions. Brain specific expression causes the formation of sporadic sense DPRs aggregates upon 6 months dox induction but no apparent neurodegeneration. Expression in the rest of the body evokes abundant sense DPRs in multiple organs, leading to weight loss, neuromuscular junction disruption, myopathy, and a locomotor phenotype within the time frame of four weeks. We did not observe any RNA foci or pTDP-43 pathology. Accumulation of DPRs and the myopathy phenotype could be prevented when 36x G4C2 repeat expression was stopped after 1 week. After 2 weeks of expression, the phenotype could not be reversed, even though DPR levels were reduced. In conclusion, expression of 36x pure G4C2 repeats including 100bp human flanking regions is sufficient for RAN translation of sense DPRs and evokes a functional locomotor phenotype. Our inducible mouse model suggests early diagnosis and treatment are important for C9FTD/ALS patients.
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Affiliation(s)
- F W Riemslagh
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - E C van der Toorn
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - R F M Verhagen
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - A Maas
- Department of Cell Biology, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - L W J Bosman
- Department of Neuroscience, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - R K Hukema
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - R Willemsen
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
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23
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Hutten S, Usluer S, Bourgeois B, Simonetti F, Odeh HM, Fare CM, Czuppa M, Hruska-Plochan M, Hofweber M, Polymenidou M, Shorter J, Edbauer D, Madl T, Dormann D. Nuclear Import Receptors Directly Bind to Arginine-Rich Dipeptide Repeat Proteins and Suppress Their Pathological Interactions. Cell Rep 2020; 33:108538. [PMID: 33357437 PMCID: PMC7814465 DOI: 10.1016/j.celrep.2020.108538] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [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: 08/10/2020] [Revised: 11/06/2020] [Accepted: 11/25/2020] [Indexed: 12/13/2022] Open
Abstract
Nuclear import receptors, also called importins, mediate nuclear import of proteins and chaperone aggregation-prone cargoes (e.g., neurodegeneration-linked RNA-binding proteins [RBPs]) in the cytoplasm. Importins were identified as modulators of cellular toxicity elicited by arginine-rich dipeptide repeat proteins (DPRs), an aberrant protein species found in C9orf72-linked amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Mechanistically, the link between importins and arginine-rich DPRs remains unclear. Here, we show that arginine-rich DPRs (poly-GR and poly-PR) bind directly to multiple importins and, in excess, promote their insolubility and condensation. In cells, poly-GR impairs Impα/β-mediated nuclear import, including import of TDP-43, an RBP that aggregates in C9orf72-ALS/FTD patients. Arginine-rich DPRs promote phase separation and insolubility of TDP-43 in vitro and in cells, and this pathological interaction is suppressed by elevating importin concentrations. Our findings suggest that importins can decrease toxicity of arginine-rich DPRs by suppressing their pathological interactions.
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Affiliation(s)
- Saskia Hutten
- BioMedical Center (BMC), Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany.
| | - Sinem Usluer
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology & Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Benjamin Bourgeois
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology & Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Francesca Simonetti
- BioMedical Center (BMC), Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Hana M Odeh
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Charlotte M Fare
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mareike Czuppa
- German Center for Neurodegenerative Diseases (DZNE), Munich, Feodor-Lynen-Str. 17, 81377 Munich, Germany
| | - Marian Hruska-Plochan
- Department of Quantitative Biomedicine, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Mario Hofweber
- BioMedical Center (BMC), Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany; LMU Graduate School of Systemic Neurosciences (GSN), 82152 Planegg-Martinsried, Germany
| | - Magdalini Polymenidou
- Department of Quantitative Biomedicine, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Dieter Edbauer
- German Center for Neurodegenerative Diseases (DZNE), Munich, Feodor-Lynen-Str. 17, 81377 Munich, Germany; LMU Graduate School of Systemic Neurosciences (GSN), 82152 Planegg-Martinsried, Germany; Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Tobias Madl
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology & Biochemistry, Medical University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria
| | - Dorothee Dormann
- BioMedical Center (BMC), Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany; LMU Graduate School of Systemic Neurosciences (GSN), 82152 Planegg-Martinsried, Germany; Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany.
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24
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Quaegebeur A, Glaria I, Lashley T, Isaacs AM. Soluble and insoluble dipeptide repeat protein measurements in C9orf72-frontotemporal dementia brains show regional differential solubility and correlation of poly-GR with clinical severity. Acta Neuropathol Commun 2020; 8:184. [PMID: 33168090 DOI: 10.1186/s40478-020-01036-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 09/06/2020] [Indexed: 12/14/2022] Open
Abstract
A C9orf72 repeat expansion is the most common genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis. One of the suggested pathomechanisms is toxicity from dipeptide repeat proteins (DPRs), which are generated via unconventional translation of sense and antisense repeat transcripts with poly-GA, poly-GP and poly-GR being the most abundant dipeptide proteins. Animal and cellular studies highlight a neurotoxic role of poly-GR and poly-PR and to a lesser degree of poly-GA. Human post-mortem studies in contrast have been much less clear on a potential role of DPR toxicity but have largely focused on immunohistochemical methods to detect aggregated DPR inclusions. This study uses protein fractionation and sensitive immunoassays to quantify not only insoluble but also soluble poly-GA, poly-GP and poly-GR concentrations in brain homogenates of FTD patients with C9orf72 mutation across four brain regions. We show that soluble DPRs are less abundant in clinically affected areas (i.e. frontal and temporal cortices). In contrast, the cerebellum not only shows the largest DPR load but also the highest relative DPR solubility. Finally, poly-GR levels and poly-GP solubility correlate with clinical severity. These findings provide the first cross-comparison of soluble and insoluble forms of all sense DPRs and shed light on the distribution and role of soluble DPRs in the etiopathogenesis of human C9orf72-FTD.
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25
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Chen YJ, Yang JE. Role of liquid-liquid phase separation in cell physiology and diseases. Shijie Huaren Xiaohua Zazhi 2020; 28:884-890. [DOI: 10.11569/wcjd.v28.i18.884] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
There are many liquid-like membraneless compartments in eukaryotic cells. Recent studies have shown that these membraneless compartments are formed through liquid-liquid phase separation (LLPS), driven by proteins, nucleic acids, and other biomacromolecules. LLPS is involved in different cell activities such as regulation of gene expression, signal transduction, stress response and so on. It is shown that dysregulation of LLPS is associated with neurodegenerative disease and cancer. This review discusses the formation and regulation of liquid-liquid separation and their roles in cell physiology and diseases.
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Affiliation(s)
- Ya-Jing Chen
- Key Laboratory of Gene Function and Regulation of the Ministry of Education, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, Guangdong Province, China
| | - Jin-E Yang
- Key Laboratory of Gene Function and Regulation of the Ministry of Education, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, Guangdong Province, China
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26
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Pakravan D, Orlando G, Bercier V, Van Den Bosch L. Role and therapeutic potential of liquid-liquid phase separation in amyotrophic lateral sclerosis. J Mol Cell Biol 2020; 13:15-28. [PMID: 32976566 PMCID: PMC8036000 DOI: 10.1093/jmcb/mjaa049] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 07/24/2020] [Accepted: 08/27/2020] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a late-onset neurodegenerative disease selectively affecting motor neurons, leading to progressive paralysis. Although most cases are sporadic, ∼10% are familial. Similar proteins are found in aggregates in sporadic and familial ALS, and over the last decade, research has been focused on the underlying nature of this common pathology. Notably, TDP-43 inclusions are found in almost all ALS patients, while FUS inclusions have been reported in some familial ALS patients. Both TDP-43 and FUS possess ‘low-complexity domains’ (LCDs) and are considered as ‘intrinsically disordered proteins’, which form liquid droplets in vitro due to the weak interactions caused by the LCDs. Dysfunctional ‘liquid–liquid phase separation’ (LLPS) emerged as a new mechanism linking ALS-related proteins to pathogenesis. Here, we review the current state of knowledge on ALS-related gene products associated with a proteinopathy and discuss their status as LLPS proteins. In addition, we highlight the therapeutic potential of targeting LLPS for treating ALS.
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Affiliation(s)
- Donya Pakravan
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Leuven—University of Leuven, 3000 Leuven, Belgium
- Laboratory of Neurobiology, VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium
| | - Gabriele Orlando
- Switch Laboratory, VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium
| | - Valérie Bercier
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Leuven—University of Leuven, 3000 Leuven, Belgium
- Laboratory of Neurobiology, VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium
| | - Ludo Van Den Bosch
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Leuven—University of Leuven, 3000 Leuven, Belgium
- Laboratory of Neurobiology, VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium
- Correspondence to: Ludo Van Den Bosch, E-mail:
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27
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Premasiri AS, Gill AL, Vieira FG. Type I PRMT Inhibition Protects Against C9ORF72 Arginine-Rich Dipeptide Repeat Toxicity. Front Pharmacol 2020; 11:569661. [PMID: 33013410 PMCID: PMC7508178 DOI: 10.3389/fphar.2020.569661] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 08/19/2020] [Indexed: 12/13/2022] Open
Abstract
Repeat expansion mutations in the C9ORF72 gene are the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Repeat-associated non-AUG translation of this expansion produces dipeptide repeat proteins (DRPs). The arginine containing DRPs, polyGR and polyPR, are consistently reported to be the most toxic. Here we demonstrated that small molecule inhibition of type I protein arginine methyltransferases (PRMT) protects against polyGR and polyPR toxicity. Furthermore, our findings suggest that asymmetric dimethylation of polyGR and polyPR by Type I PRMTs plays important roles in their cytotoxicity.
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28
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He F, Flores BN, Krans A, Frazer M, Natla S, Niraula S, Adefioye O, Barmada SJ, Todd PK. The carboxyl termini of RAN translated GGGGCC nucleotide repeat expansions modulate toxicity in models of ALS/FTD. Acta Neuropathol Commun 2020; 8:122. [PMID: 32753055 PMCID: PMC7401224 DOI: 10.1186/s40478-020-01002-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 07/22/2020] [Indexed: 12/13/2022] Open
Abstract
An intronic hexanucleotide repeat expansion in C9ORF72 causes familial and sporadic amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). This repeat is thought to elicit toxicity through RNA mediated protein sequestration and repeat-associated non-AUG (RAN) translation of dipeptide repeat proteins (DPRs). We generated a series of transgenic Drosophila models expressing GGGGCC (G4C2) repeats either inside of an artificial intron within a GFP reporter or within the 5' untranslated region (UTR) of GFP placed in different downstream reading frames. Expression of 484 intronic repeats elicited minimal alterations in eye morphology, viability, longevity, or larval crawling but did trigger RNA foci formation, consistent with prior reports. In contrast, insertion of repeats into the 5' UTR elicited differential toxicity that was dependent on the reading frame of GFP relative to the repeat. Greater toxicity correlated with a short and unstructured carboxyl terminus (C-terminus) in the glycine-arginine (GR) RAN protein reading frame. This change in C-terminal sequence triggered nuclear accumulation of all three RAN DPRs. A similar differential toxicity and dependence on the GR C-terminus was observed when repeats were expressed in rodent neurons. The presence of the native C-termini across all three reading frames was partly protective. Taken together, these findings suggest that C-terminal sequences outside of the repeat region may alter the behavior and toxicity of dipeptide repeat proteins derived from GGGGCC repeats.
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29
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Abstract
Defective nucleocytoplasmic transport contributes to C9-ALS/FTD, but an inventory of proteins that become redistributed has remained elusive. In this issue of Neuron, Ortega et al. (2020) catalog these redistributed proteins and pinpoint nonsense-mediated decay as a therapeutic target for C9-ALS/FTD.
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Affiliation(s)
- Hana M Odeh
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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