1
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Tsekrekou M, Giannakou M, Papanikolopoulou K, Skretas G. Protein aggregation and therapeutic strategies in SOD1- and TDP-43- linked ALS. Front Mol Biosci 2024; 11:1383453. [PMID: 38855322 PMCID: PMC11157337 DOI: 10.3389/fmolb.2024.1383453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 05/02/2024] [Indexed: 06/11/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with severe socio-economic impact. A hallmark of ALS pathology is the presence of aberrant cytoplasmic inclusions composed of misfolded and aggregated proteins, including both wild-type and mutant forms. This review highlights the critical role of misfolded protein species in ALS pathogenesis, particularly focusing on Cu/Zn superoxide dismutase (SOD1) and TAR DNA-binding protein 43 (TDP-43), and emphasizes the urgent need for innovative therapeutic strategies targeting these misfolded proteins directly. Despite significant advancements in understanding ALS mechanisms, the disease remains incurable, with current treatments offering limited clinical benefits. Through a comprehensive analysis, the review focuses on the direct modulation of the misfolded proteins and presents recent discoveries in small molecules and peptides that inhibit SOD1 and TDP-43 aggregation, underscoring their potential as effective treatments to modify disease progression and improve clinical outcomes.
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Affiliation(s)
- Maria Tsekrekou
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens, Greece
| | - Maria Giannakou
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens, Greece
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Katerina Papanikolopoulou
- Institute for Fundamental Biomedical Research, Biomedical Sciences Research Centre “Alexander Fleming”, Vari, Greece
- ResQ Biotech, Patras Science Park, Rio, Greece
| | - Georgios Skretas
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens, Greece
- ResQ Biotech, Patras Science Park, Rio, Greece
- Institute for Bio-innovation, Biomedical Sciences Research Centre “Alexander Fleming”, Vari, Greece
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2
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Baker CC, Gallicchio L, Matias NR, Porter DF, Parsanian L, Taing E, Tam C, Fuller MT. Cell-type-specific interacting proteins collaborate to regulate the timing of Cyclin B protein expression in male meiotic prophase. Development 2023; 150:dev201709. [PMID: 37882771 PMCID: PMC10730016 DOI: 10.1242/dev.201709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 10/10/2023] [Indexed: 10/27/2023]
Abstract
During meiosis, germ cell and stage-specific components impose additional layers of regulation on the core cell cycle machinery to set up an extended G2 period termed meiotic prophase. In Drosophila males, meiotic prophase lasts 3.5 days, during which spermatocytes upregulate over 1800 genes and grow 25-fold. Previous work has shown that the cell cycle regulator Cyclin B (CycB) is subject to translational repression in immature spermatocytes, mediated by the RNA-binding protein Rbp4 and its partner Fest. Here, we show that the spermatocyte-specific protein Lut is required for translational repression of cycB in an 8-h window just before spermatocytes are fully mature. In males mutant for rbp4 or lut, spermatocytes enter and exit meiotic division 6-8 h earlier than in wild type. In addition, spermatocyte-specific isoforms of Syncrip (Syp) are required for expression of CycB protein in mature spermatocytes and normal entry into the meiotic divisions. Lut and Syp interact with Fest independent of RNA. Thus, a set of spermatocyte-specific regulators choreograph the timing of expression of CycB protein during male meiotic prophase.
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Affiliation(s)
- Catherine C. Baker
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lorenzo Gallicchio
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Neuza R. Matias
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Douglas F. Porter
- Program in Epithelial Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lucineh Parsanian
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Emily Taing
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Cheuk Tam
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Margaret T. Fuller
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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3
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Ogami K, Ogawa K, Sanpei S, Ichikawa F, Udagawa T, Hoshino SI. A Combinatorial Code for CPEB-Mediated c-myc Repression. Cells 2023; 12:2410. [PMID: 37830624 PMCID: PMC10572585 DOI: 10.3390/cells12192410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 10/03/2023] [Accepted: 10/04/2023] [Indexed: 10/14/2023] Open
Abstract
During early embryonic development, the RNA-binding protein CPEB mediates cytoplasmic polyadenylation and translational activation through a combinatorial code defined by the cy-toplasmic polyadenylation element (CPE) present in maternal mRNAs. However, in non-neuronal somatic cells, CPEB accelerates deadenylation to repress translation of the target, including c-myc mRNA, through an ill-defined cis-regulatory mechanism. Using RNA mutagenesis and electrophoretic mobility shift assays, we demonstrated that a combination of tandemly arranged consensus (cCPE) and non-consensus (ncCPE) cytoplasmic polyadenylation elements (CPEs) constituted a combinatorial code for CPEB-mediated c-myc mRNA decay. CPEB binds to cCPEs with high affinity (Kd = ~250 nM), whereas it binds to ncCPEs with low affinity (Kd > ~900 nM). CPEB binding to a cCPE enhances CPEB binding to the proximal ncCPE. In contrast, while a cCPE did not activate mRNA degradation, an ncCPE was essential for the induction of degradation, and a combination of a cCPE and ncCPEs further promoted degradation. Based on these findings, we propose a model in which the high-affinity binding of CPEB to the cCPE accelerates the binding of the second CPEB to the ncCPEs, resulting in the recruitment of deadenylases, acceleration of deadenylation, and repression of c-myc mRNAs.
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Affiliation(s)
- Koichi Ogami
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan (F.I.); (T.U.)
- Division of Molecular Oncology, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Keima Ogawa
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan (F.I.); (T.U.)
| | - Shoko Sanpei
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan (F.I.); (T.U.)
| | - Fumito Ichikawa
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan (F.I.); (T.U.)
| | - Tsuyoshi Udagawa
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan (F.I.); (T.U.)
| | - Shin-ichi Hoshino
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan (F.I.); (T.U.)
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4
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Baker CC, Gallicchio L, Parsanian L, Taing E, Tam C, Fuller MT. A cell-type-specific multi-protein complex regulates expression of Cyclin B protein in Drosophila male meiotic prophase. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.16.528869. [PMID: 36824933 PMCID: PMC9949121 DOI: 10.1101/2023.02.16.528869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
During meiosis, germ cell and stage-specific components impose additional layers of regulation on the core cell cycle machinery to set up an extended G2 period termed meiotic prophase. In Drosophila males, meiotic prophase lasts 3.5 days, during which spermatocytes turn up expression of over 3000 genes and grow 25-fold in volume. Previous work showed that the core cell cycle regulator Cyclin B (CycB) is subject to translational repression in immature Drosophila spermatocytes, mediated by the RNA-binding protein Rbp4 and its partner Fest. Here we show that another spermatocyte-specific protein, Lut, is required for translational repression of cycB in an 8-hour window just before spermatocytes are fully mature. In males mutant for rbp4 or lut , spermatocytes enter and exit the meiotic divisions 6-8 hours earlier than in wild-type. In addition, we show that spermatocyte-specific isoforms of Syncrip (Syp) are required for expression of CycB protein and normal entry into the meiotic divisions. Both Lut and Syp interact with Fest in an RNA-independent manner. Thus a complex of spermatocyte-specific regulators choreograph the timing of expression of CycB protein during male meiotic prophase. SUMMARY STATEMENT Expression of a conserved cell cycle component, Cyclin B, is regulated by multiple mechanisms in the Drosophila male germline to dictate the correct timing of meiotic division.
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5
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Will Cannabigerol Trigger Neuroregeneration after a Spinal Cord Injury? An In Vitro Answer from NSC-34 Scratch-Injured Cells Transcriptome. Pharmaceuticals (Basel) 2022; 15:ph15020117. [PMID: 35215230 PMCID: PMC8875351 DOI: 10.3390/ph15020117] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/12/2022] [Accepted: 01/17/2022] [Indexed: 02/07/2023] Open
Abstract
Spinal cord injury affects the lives of millions of people around the world, often causing disability and, in unfortunate circumstances, death. Rehabilitation can partly improve outcomes and only a small percentage of patients, typically the least injured, can hope to return to normal living conditions. Cannabis sativa is gaining more and more interest in recent years, even though its beneficial properties have been known for thousands of years. Cannabigerol (CBG), extracted from C. sativa, is defined as the “mother of all cannabinoids” and its properties range from anti-inflammatory to antioxidant and neuroprotection. Using NSC-34 cells to model spinal cord injury in vitro, our work evaluated the properties of CBG treatments in motor neuron regeneration. While pre-treatment can modulate oxidative stress and increase antioxidant enzyme genes, such as Tnx1, decreasing Nos1 post-treatment seems to induce regeneration genes by triggering different pathways, such as Gap43 via p53 acetylation by Ep300 and Ddit3 and Xbp1 via Bdnf signaling, along with cytoskeletal remodeling signaling genes Nrp1 and Map1b. Our results indicate CBG as a phytocompound worth further investigation in the field of neuronal regeneration.
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6
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Genetic architecture of motor neuron diseases. J Neurol Sci 2021; 434:120099. [PMID: 34965490 DOI: 10.1016/j.jns.2021.120099] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/26/2021] [Accepted: 12/14/2021] [Indexed: 12/18/2022]
Abstract
Motor neuron diseases (MNDs) are rare and frequently fatal neurological disorders in which motor neurons within the brainstem and spinal cord regions slowly die. MNDs are primarily caused by genetic mutations, and > 100 different mutant genes in humans have been discovered thus far. Given the fact that many more MND-related genes have yet to be discovered, the growing body of genetic evidence has offered new insights into the diverse cellular and molecular mechanisms involved in the aetiology and pathogenesis of MNDs. This search may aid in the selection of potential candidate genes for future investigation and, eventually, may open the door to novel interventions to slow down disease progression. In this review paper, we have summarized detailed existing research findings of different MNDs, such as amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), spinal bulbar muscle atrophy (SBMA) and hereditary spastic paraplegia (HSP) in relation to their complex genetic architecture.
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7
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Meneses A, Koga S, O’Leary J, Dickson DW, Bu G, Zhao N. TDP-43 Pathology in Alzheimer’s Disease. Mol Neurodegener 2021; 16:84. [PMID: 34930382 PMCID: PMC8691026 DOI: 10.1186/s13024-021-00503-x] [Citation(s) in RCA: 88] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 11/21/2021] [Indexed: 12/05/2022] Open
Abstract
Transactive response DNA binding protein of 43 kDa (TDP-43) is an intranuclear protein encoded by the TARDBP gene that is involved in RNA splicing, trafficking, stabilization, and thus, the regulation of gene expression. Cytoplasmic inclusion bodies containing phosphorylated and truncated forms of TDP-43 are hallmarks of amyotrophic lateral sclerosis (ALS) and a subset of frontotemporal lobar degeneration (FTLD). Additionally, TDP-43 inclusions have been found in up to 57% of Alzheimer’s disease (AD) cases, most often in a limbic distribution, with or without hippocampal sclerosis. In some cases, TDP-43 deposits are also found in neurons with neurofibrillary tangles. AD patients with TDP-43 pathology have increased severity of cognitive impairment compared to those without TDP-43 pathology. Furthermore, the most common genetic risk factor for AD, apolipoprotein E4 (APOE4), is associated with increased frequency of TDP-43 pathology. These findings provide strong evidence that TDP-43 pathology is an integral part of multiple neurodegenerative conditions, including AD. Here, we review the biology and pathobiology of TDP-43 with a focus on its role in AD. We emphasize the need for studies on the mechanisms that lead to TDP-43 pathology, especially in the setting of age-related disorders such as AD.
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8
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Terryn J, Verfaillie CM, Van Damme P. Tweaking Progranulin Expression: Therapeutic Avenues and Opportunities. Front Mol Neurosci 2021; 14:713031. [PMID: 34366786 PMCID: PMC8343103 DOI: 10.3389/fnmol.2021.713031] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 07/07/2021] [Indexed: 01/01/2023] Open
Abstract
Frontotemporal dementia (FTD) is a neurodegenerative disease, leading to behavioral changes and language difficulties. Heterozygous loss-of-function mutations in progranulin (GRN) induce haploinsufficiency of the protein and are associated with up to one-third of all genetic FTD cases worldwide. While the loss of GRN is primarily associated with neurodegeneration, the biological functions of the secreted growth factor-like protein are more diverse, ranging from wound healing, inflammation, vasculogenesis, and metabolic regulation to tumor cell growth and metastasis. To date, no disease-modifying treatments exist for FTD, but different therapeutic approaches to boost GRN levels in the central nervous system are currently being developed (including AAV-mediated GRN gene delivery as well as anti-SORT1 antibody therapy). In this review, we provide an overview of the multifaceted regulation of GRN levels and the corresponding therapeutic avenues. We discuss the opportunities, advantages, and potential drawbacks of the diverse approaches. Additionally, we highlight the therapeutic potential of elevating GRN levels beyond patients with loss-of-function mutations in GRN.
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Affiliation(s)
- Joke Terryn
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Leuven-University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Catherine M Verfaillie
- Department of Development and Regeneration, Interdepartmental Stem Cell Institute, KU Leuven-University of Leuven, Leuven, Belgium
| | - Philip Van Damme
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Leuven-University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, Leuven, Belgium
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9
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Wood A, Gurfinkel Y, Polain N, Lamont W, Lyn Rea S. Molecular Mechanisms Underlying TDP-43 Pathology in Cellular and Animal Models of ALS and FTLD. Int J Mol Sci 2021; 22:4705. [PMID: 33946763 PMCID: PMC8125728 DOI: 10.3390/ijms22094705] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/22/2021] [Accepted: 04/28/2021] [Indexed: 02/03/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) are neurodegenerative disorders that exist on a disease spectrum due to pathological, clinical and genetic overlap. In up to 97% of ALS cases and ~50% of FTLD cases, the primary pathological protein observed in affected tissues is TDP-43, which is hyperphosphorylated, ubiquitinated and cleaved. The TDP-43 is observed in aggregates that are abnormally located in the cytoplasm. The pathogenicity of TDP-43 cytoplasmic aggregates may be linked with both a loss of nuclear function and a gain of toxic functions. The cellular processes involved in ALS and FTLD disease pathogenesis include changes to RNA splicing, abnormal stress granules, mitochondrial dysfunction, impairments to axonal transport and autophagy, abnormal neuromuscular junctions, endoplasmic reticulum stress and the subsequent induction of the unfolded protein response. Here, we review and discuss the evidence for alterations to these processes that have been reported in cellular and animal models of TDP-43 proteinopathy.
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Affiliation(s)
- Alistair Wood
- School of Molecular Science, University of Western Australia, Nedlands 6009, Australia;
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Health Research Building, Discovery Way, Murdoch 6150, Australia; (Y.G.); (N.P.)
| | - Yuval Gurfinkel
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Health Research Building, Discovery Way, Murdoch 6150, Australia; (Y.G.); (N.P.)
- Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands 6009, Australia;
| | - Nicole Polain
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Health Research Building, Discovery Way, Murdoch 6150, Australia; (Y.G.); (N.P.)
| | - Wesley Lamont
- Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands 6009, Australia;
| | - Sarah Lyn Rea
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Health Research Building, Discovery Way, Murdoch 6150, Australia; (Y.G.); (N.P.)
- Hub for Immersive Visualisation and eResearch, Curtin University, Bentley 6102, Australia
- Harry Perkins Institute of Medical Research, Centre for Medical Research, University of Western Australia, Nedlands 6009, Australia
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10
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Inagaki H, Hosoda N, Hoshino SI. DDX6 is a positive regulator of Ataxin-2/PAPD4 cytoplasmic polyadenylation machinery. Biochem Biophys Res Commun 2021; 553:9-16. [PMID: 33756349 DOI: 10.1016/j.bbrc.2021.03.066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 03/12/2021] [Indexed: 12/20/2022]
Abstract
The RNA-binding protein Ataxin-2 regulates translation and mRNA stability through cytoplasmic polyadenylation of the targets. Here we newly identified DDX6 as a positive regulator of the cytoplasmic polyadenylation. Analysis of Ataxin-2 interactome using LC-MS/MS revealed prominent interaction with the DEAD-box RNA helicase DDX6. DDX6 interacted with components of the Ataxin-2 polyadenylation machinery; Ataxin-2, PABPC1 and PAPD4. As in the case for Ataxin-2 downregulation, DDX6 downregulation led to an increase in Ataxin-2 target mRNAs with short poly(A) tails as well as a reduction in their protein expression. In contrast, Ataxin-2 target mRNAs with short poly(A) tails were decreased by the overexpression of Ataxin-2, which was compromised by the DDX6 downregulation. However, polyadenylation induced by Ataxin-2 tethering was not affected by the DDX6 downregulation. Taken together, these results suggest that DDX6 positively regulates Ataxin-2-induced cytoplasmic polyadenylation to maintain poly(A) tail length of the Ataxin-2 targets provably through accelerating binding of Ataxin-2 to the target mRNAs.
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Affiliation(s)
- Hiroto Inagaki
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
| | - Nao Hosoda
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
| | - Shin-Ichi Hoshino
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan.
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11
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The Alphaviral Capsid Protein Inhibits IRAK1-Dependent TLR Signaling. Viruses 2021; 13:v13030377. [PMID: 33673546 PMCID: PMC7997285 DOI: 10.3390/v13030377] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 02/24/2021] [Accepted: 02/26/2021] [Indexed: 12/20/2022] Open
Abstract
Alphaviruses are arthropod-borne RNA viruses which can cause either mild to severe febrile arthritis which may persist for months, or encephalitis which can lead to death or lifelong cognitive impairments. The non-assembly molecular role(s), functions, and protein–protein interactions of the alphavirus capsid proteins have been largely overlooked. Here we detail the use of a BioID2 biotin ligase system to identify the protein–protein interactions of the Sindbis virus capsid protein. These efforts led to the discovery of a series of novel host–pathogen interactions, including the identification of an interaction between the alphaviral capsid protein and the host IRAK1 protein. Importantly, this capsid–IRAK1 interaction is conserved across multiple alphavirus species, including arthritogenic alphaviruses SINV, Ross River virus, and Chikungunya virus; and encephalitic alphaviruses Eastern Equine Encephalitis virus, and Venezuelan Equine Encephalitis virus. The impact of the capsid–IRAK1 interaction was evaluated using a robust set of cellular model systems, leading to the realization that the alphaviral capsid protein specifically inhibits IRAK1-dependent signaling. This inhibition represents a means by which alphaviruses may evade innate immune detection and activation prior to viral gene expression. Altogether, these data identify novel capsid protein–protein interactions, establish the capsid–IRAK1 interaction as a common alphavirus host–pathogen interface, and delineate the molecular consequences of the capsid–IRAK1 interaction on IRAK1-dependent signaling.
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12
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Kim G, Gautier O, Tassoni-Tsuchida E, Ma XR, Gitler AD. ALS Genetics: Gains, Losses, and Implications for Future Therapies. Neuron 2020; 108:822-842. [PMID: 32931756 PMCID: PMC7736125 DOI: 10.1016/j.neuron.2020.08.022] [Citation(s) in RCA: 207] [Impact Index Per Article: 51.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 08/01/2020] [Accepted: 08/21/2020] [Indexed: 02/06/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder caused by the loss of motor neurons from the brain and spinal cord. The ALS community has made remarkable strides over three decades by identifying novel familial mutations, generating animal models, elucidating molecular mechanisms, and ultimately developing promising new therapeutic approaches. Some of these approaches reduce the expression of mutant genes and are in human clinical trials, highlighting the need to carefully consider the normal functions of these genes and potential contribution of gene loss-of-function to ALS. Here, we highlight known loss-of-function mechanisms underlying ALS, potential consequences of lowering levels of gene products, and the need to consider both gain and loss of function to develop safe and effective therapeutic strategies.
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Affiliation(s)
- Garam Kim
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA; Stanford Neurosciences Interdepartmental Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Olivia Gautier
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA; Stanford Neurosciences Interdepartmental Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Eduardo Tassoni-Tsuchida
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - X Rosa Ma
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Aaron D Gitler
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA.
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13
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Inagaki H, Hosoda N, Tsuiji H, Hoshino SI. Direct evidence that Ataxin-2 is a translational activator mediating cytoplasmic polyadenylation. J Biol Chem 2020; 295:15810-15825. [PMID: 32989052 DOI: 10.1074/jbc.ra120.013835] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 09/13/2020] [Indexed: 12/27/2022] Open
Abstract
The RNA-binding protein Ataxin-2 binds to and stabilizes a number of mRNA sequences, including that of the transactive response DNA-binding protein of 43 kDa (TDP-43). Ataxin-2 is additionally involved in several processes requiring translation, such as germline formation, long-term habituation, and circadian rhythm formation. However, it has yet to be unambiguously demonstrated that Ataxin-2 is actually involved in activating the translation of its target mRNAs. Here we provide direct evidence from a polysome profile analysis showing that Ataxin-2 enhances translation of target mRNAs. Our recently established method for transcriptional pulse-chase analysis under conditions of suppressing deadenylation revealed that Ataxin-2 promotes post-transcriptional polyadenylation of the target mRNAs. Furthermore, Ataxin-2 binds to a poly(A)-binding protein PABPC1 and a noncanonical poly(A) polymerase PAPD4 via its intrinsically disordered region (amino acids 906-1095) to recruit PAPD4 to the targets. Post-transcriptional polyadenylation by Ataxin-2 explains not only how it activates translation but also how it stabilizes target mRNAs, including TDP-43 mRNA. Ataxin-2 is known to be a potent modifier of TDP-43 proteinopathies and to play a causative role in the neurodegenerative disease spinocerebellar ataxia type 2, so these findings suggest that Ataxin-2-induced cytoplasmic polyadenylation and activation of translation might impact neurodegeneration (i.e. TDP-43 proteinopathies), and this process could be a therapeutic target for Ataxin-2-related neurodegenerative disorders.
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Affiliation(s)
- Hiroto Inagaki
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Nao Hosoda
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Hitomi Tsuiji
- Department of Biomedical Science, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Shin-Ichi Hoshino
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan.
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14
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Abstract
RNA-binding proteins are a critical group of multifunctional proteins that precisely regulate all aspects of gene expression, from alternative splicing to mRNA trafficking, stability, and translation. Converging evidence highlights aberrant RNA metabolism as a common pathogenic mechanism in several neurodevelopmental and neurodegenerative diseases. However, dysregulation of disease-linked RNA-binding proteins results in widespread, often tissue-specific and/or pleiotropic effects on the transcriptome, making it challenging to determine the underlying cellular and molecular mechanisms that contribute to disease pathogenesis. Understanding how splicing misregulation as well as alterations of mRNA stability and localization impact the activity and function of neuronal proteins is fundamental to addressing neurodevelopmental defects and synaptic dysfunction in disease. Here we highlight recent exciting studies that use high-throughput transcriptomic analysis and advanced genetic, cell biological, and imaging approaches to dissect the role of disease-linked RNA-binding proteins on different RNA processing steps. We focus specifically on efforts to elucidate the functional consequences of aberrant RNA processing on neuronal morphology, synaptic activity and plasticity in development and disease. We also consider new areas of investigation that will elucidate the molecular mechanisms RNA-binding proteins use to achieve spatiotemporal control of gene expression for neuronal homeostasis and plasticity.
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Affiliation(s)
- Shavanie Prashad
- Department of Pathology, Yale University School of Medicine, Yale University, New Haven, CT, USA.,Experimental Pathology Graduate Group, Yale University School of Medicine, Yale University, New Haven, CT, USA
| | - Pallavi P Gopal
- Department of Pathology, Yale University School of Medicine, Yale University, New Haven, CT, USA.,Experimental Pathology Graduate Group, Yale University School of Medicine, Yale University, New Haven, CT, USA.,Yale Center for RNA Science and Medicine, Yale University School of Medicine, Yale University, New Haven, CT, USA
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15
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Herzog JJ, Xu W, Deshpande M, Rahman R, Suib H, Rodal AA, Rosbash M, Paradis S. TDP-43 dysfunction restricts dendritic complexity by inhibiting CREB activation and altering gene expression. Proc Natl Acad Sci U S A 2020; 117:11760-11769. [PMID: 32393629 PMCID: PMC7260973 DOI: 10.1073/pnas.1917038117] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are two related neurodegenerative diseases that present with similar TDP-43 pathology in patient tissue. TDP-43 is an RNA-binding protein which forms aggregates in neurons of ALS and FTD patients as well as in a subset of patients diagnosed with other neurodegenerative diseases. Despite our understanding that TDP-43 is essential for many aspects of RNA metabolism, it remains obscure how TDP-43 dysfunction contributes to neurodegeneration. Interestingly, altered neuronal dendritic morphology is a common theme among several neurological disorders and is thought to precede neurodegeneration. We previously found that both TDP-43 overexpression (OE) and knockdown (KD) result in reduced dendritic branching of cortical neurons. In this study, we used TRIBE (targets of RNA-binding proteins identified by editing) as an approach to identify signaling pathways that regulate dendritic branching downstream of TDP-43. We found that TDP-43 RNA targets are enriched for pathways that signal to the CREB transcription factor. We further found that TDP-43 dysfunction inhibits CREB activation and CREB transcriptional output, and restoring CREB signaling rescues defects in dendritic branching. Finally, we demonstrate, using RNA sequencing, that TDP-43 OE and KD cause similar changes in the abundance of specific messenger RNAs, consistent with their ability to produce similar morphological defects. Our data therefore provide a mechanism by which TDP-43 dysfunction interferes with dendritic branching, and may define pathways for therapeutic intervention in neurodegenerative diseases.
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Affiliation(s)
- Josiah J Herzog
- Department of Biology, Brandeis University, Waltham, MA 02453
- Volen Center for Complex Systems, Brandeis University, Waltham, MA 02453
| | - Weijin Xu
- Department of Biology, Brandeis University, Waltham, MA 02453
- Howard Hughes Medical Institute, Brandeis University, Waltham, MA 02453
| | - Mugdha Deshpande
- Department of Biology, Brandeis University, Waltham, MA 02453
- Volen Center for Complex Systems, Brandeis University, Waltham, MA 02453
| | - Reazur Rahman
- Department of Biology, Brandeis University, Waltham, MA 02453
- Howard Hughes Medical Institute, Brandeis University, Waltham, MA 02453
| | - Hannah Suib
- Department of Biology, Brandeis University, Waltham, MA 02453
- Volen Center for Complex Systems, Brandeis University, Waltham, MA 02453
| | - Avital A Rodal
- Department of Biology, Brandeis University, Waltham, MA 02453
| | - Michael Rosbash
- Department of Biology, Brandeis University, Waltham, MA 02453;
- Howard Hughes Medical Institute, Brandeis University, Waltham, MA 02453
| | - Suzanne Paradis
- Department of Biology, Brandeis University, Waltham, MA 02453;
- Volen Center for Complex Systems, Brandeis University, Waltham, MA 02453
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Gumina V, Onesto E, Colombrita C, Maraschi A, Silani V, Ratti A. Inter-Species Differences in Regulation of the Progranulin-Sortilin Axis in TDP-43 Cell Models of Neurodegeneration. Int J Mol Sci 2019; 20:ijms20235866. [PMID: 31766750 PMCID: PMC6928728 DOI: 10.3390/ijms20235866] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/13/2019] [Accepted: 11/20/2019] [Indexed: 01/03/2023] Open
Abstract
Cytoplasmic aggregates and nuclear depletion of the ubiquitous RNA-binding protein TDP-43 have been described in the autoptic brain tissues of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTLD) patients and both TDP-43 loss-of-function and gain-of-function mechanisms seem to contribute to the neurodegenerative process. Among the wide array of RNA targets, TDP-43 regulates progranulin (GRN) mRNA stability and sortilin (SORT1) splicing. Progranulin is a secreted neurotrophic and neuro-immunomodulatory factor whose endocytosis and delivery to the lysosomes are regulated by the neuronal receptor sortilin. Moreover, GRN loss-of-function mutations are causative of a subset of FTLD cases showing TDP-43 pathological aggregates. Here we show that TDP-43 loss-of-function differently affects the progranulin–sortilin axis in murine and human neuronal cell models. We demonstrated that although TDP-43 binding to GRN mRNA occurs similarly in human and murine cells, upon TDP-43 depletion, a different control of sortilin splicing and protein content may determine changes in extracellular progranulin uptake that account for increased or unchanged secreted protein in murine and human cells, respectively. As targeting the progranulin–sortilin axis has been proposed as a therapeutic approach for GRN-FTLD patients, the inter-species differences in TDP-43-mediated regulation of this pathway must be considered when translating studies from animal models to patients.
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Affiliation(s)
- Valentina Gumina
- Istituto Auxologico Italiano, IRCCS, Department of Neurology-Stroke Unit and Laboratory of Neuroscience, Via Zucchi 18, 20095 Cusano Milanino, Milan, Italy; (V.G.); (E.O.); (C.C.); (A.M.); (V.S.)
| | - Elisa Onesto
- Istituto Auxologico Italiano, IRCCS, Department of Neurology-Stroke Unit and Laboratory of Neuroscience, Via Zucchi 18, 20095 Cusano Milanino, Milan, Italy; (V.G.); (E.O.); (C.C.); (A.M.); (V.S.)
| | - Claudia Colombrita
- Istituto Auxologico Italiano, IRCCS, Department of Neurology-Stroke Unit and Laboratory of Neuroscience, Via Zucchi 18, 20095 Cusano Milanino, Milan, Italy; (V.G.); (E.O.); (C.C.); (A.M.); (V.S.)
| | - AnnaMaria Maraschi
- Istituto Auxologico Italiano, IRCCS, Department of Neurology-Stroke Unit and Laboratory of Neuroscience, Via Zucchi 18, 20095 Cusano Milanino, Milan, Italy; (V.G.); (E.O.); (C.C.); (A.M.); (V.S.)
| | - Vincenzo Silani
- Istituto Auxologico Italiano, IRCCS, Department of Neurology-Stroke Unit and Laboratory of Neuroscience, Via Zucchi 18, 20095 Cusano Milanino, Milan, Italy; (V.G.); (E.O.); (C.C.); (A.M.); (V.S.)
- Department of Pathophysiology and Transplantation, “Dino Ferrari” Center, Università degli Studi di Milano, Via F. Sforza 35, 20122 Milan, Italy
- “Aldo Ravelli” Center for Neurotechnology and Experimental Brain Therapeutics, Università degli Studi di Milano, Via A. di Rudinì 8, 20142 Milan, Italy
| | - Antonia Ratti
- Istituto Auxologico Italiano, IRCCS, Department of Neurology-Stroke Unit and Laboratory of Neuroscience, Via Zucchi 18, 20095 Cusano Milanino, Milan, Italy; (V.G.); (E.O.); (C.C.); (A.M.); (V.S.)
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Via Fratelli Cervi 93, 20090 Segrate, Milan, Italy
- Correspondence: ; Tel.: +39-02-619113045
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