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de Holanda Paranhos L, Magalhães RSS, de Araújo Brasil A, Neto JRM, Ribeiro GD, Queiroz DD, Dos Santos VM, Eleutherio ECA. The familial amyotrophic lateral sclerosis-associated A4V SOD1 mutant is not able to regulate aerobic glycolysis. Biochim Biophys Acta Gen Subj 2024; 1868:130634. [PMID: 38788983 DOI: 10.1016/j.bbagen.2024.130634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/23/2024] [Accepted: 05/20/2024] [Indexed: 05/26/2024]
Abstract
Under certain stress conditions, astrocytes operate in aerobic glycolysis, a process controlled by pyruvate dehydrogenase (PDH) inhibition through its E1 α subunit (Pda1) phosphorylation. This supplies lactate to neurons, which save glucose to obtain NADPH to, among other roles, counteract reactive oxygen species. A failure in this metabolic cooperation causes severe damage to neurons. In this work, using humanized Saccharomyces cerevisiae cells in which its endogenous Cu/Zn Superoxide Dismutase (SOD1) was replaced by human ortholog, we investigated the role of human SOD1 (hSOD1) in aerobic glycolysis regulation and its implications to amyotrophic lateral sclerosis (ALS), a neurodegenerative disease. Yeast cells ferment glucose even in the presence of oxygen and switch to respiratory metabolism after glucose exhaustion. However, like cells of SOD1-knockout strain, cells expressing A4V mutant of hSOD1 growing on glucose showed a respiratory phenotype, i.e., low glucose and high oxygen consumptions and low intracellular oxidation levels in response to peroxide stress, contrary to cells expressing wild-type (WT) SOD1 (yeast or human). The A4V mutation in hSOD1 is linked to ALS. In contrast to WT SOD1 strains, PDH activity of both sod1Δ and A4V hSOD1 cells did not change in response to a metabolic shift toward oxidative metabolism, which was associated to lower Pda1 phosphorylation levels under growth on glucose. Taken together, our results suggest that A4V mutant cannot regulate aerobic glycolysis via Pda1 phosphorylation the same way WT hSOD1, which might be linked to problems observed in the motor neurons of ALS patients with the SOD1 A4V mutation.
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Affiliation(s)
- Luan de Holanda Paranhos
- Department of Biochemistry, Institute of Chemistry, Federal University of Rio de Janeiro (UFRJ), Brazil
| | | | - Aline de Araújo Brasil
- Department of Biochemistry, Institute of Chemistry, Federal University of Rio de Janeiro (UFRJ), Brazil
| | | | - Gabriela Delaqua Ribeiro
- Department of Biochemistry, Institute of Chemistry, Federal University of Rio de Janeiro (UFRJ), Brazil
| | - Daniela Dias Queiroz
- Department of Biochemistry, Institute of Chemistry, Federal University of Rio de Janeiro (UFRJ), Brazil
| | - Vanessa Mattos Dos Santos
- Department of Biochemistry, Institute of Chemistry, Federal University of Rio de Janeiro (UFRJ), Brazil
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2
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Yuan A, Nixon RA. Posttranscriptional regulation of neurofilament proteins and tau in health and disease. Brain Res Bull 2023; 192:115-127. [PMID: 36441047 PMCID: PMC9907725 DOI: 10.1016/j.brainresbull.2022.10.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 10/20/2022] [Accepted: 10/26/2022] [Indexed: 01/16/2023]
Abstract
Neurofilament and tau proteins are neuron-specific cytoskeletal proteins that are enriched in axons, regulated by many of the same protein kinases, interact physically, and are the principal constituents of neurofibrillary lesions in major adult-onset dementias. Both proteins share functions related to the modulation of stability and functions of the microtubule network in axons, axonal transport and scaffolding of organelles, long-term synaptic potentiation, and learning and memory. Expression of these proteins is regulated not only at the transcriptional level but also through posttranscriptional control of pre-mRNA splicing, mRNA stability, transport, localization, local translation and degradation. Current evidence suggests that posttranscriptional determinants of their levels are usually regulated by RNA-binding proteins and microRNAs primarily through 3'-untranslated regions of neurofilament and tau mRNAs. Dysregulations of neurofilament and tau expression caused by mutations or pathologies of RNA-binding proteins such as TDP43, FUS and microRNAs are increasingly recognized in association with varied neurological disorders. In this review, we summarize the current understanding of posttranscriptional control of neurofilament and tau by examining the posttranscriptional regulation of neurofilament and tau by RNA-binding proteins and microRNAs implicated in health and diseases.
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Affiliation(s)
- Aidong Yuan
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA; NYU Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA.
| | - Ralph A. Nixon
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY 10962, USA,Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA,Department of Cell Biology, New York University Langone Health, New York, NY 10016, USA,NYU Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA,Correspondence to: Center for Dementia Research, Nathan Kline Institute, New York University Langone Health, New York, NY 10016, USA, (A. Yuan), (R.A. Nixon)
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3
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Tong J, Chen B, Tan PW, Kurpiewski S, Cai Z. Poly (ADP-ribose) polymerases as PET imaging targets for central nervous system diseases. Front Med (Lausanne) 2022; 9:1062432. [PMID: 36438061 PMCID: PMC9685622 DOI: 10.3389/fmed.2022.1062432] [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: 10/05/2022] [Accepted: 10/24/2022] [Indexed: 11/12/2022] Open
Abstract
Poly (ADP-ribose) polymerases (PARPs) constitute of 17 members that are associated with divergent cellular processes and play a crucial role in DNA repair, chromatin organization, genome integrity, apoptosis, and inflammation. Multiple lines of evidence have shown that activated PARP1 is associated with intense DNA damage and irritating inflammatory responses, which are in turn related to etiologies of various neurological disorders. PARP1/2 as plausible therapeutic targets have attracted considerable interests, and multitudes of PARP1/2 inhibitors have emerged for treating cancer, metabolic, inflammatory, and neurological disorders. Furthermore, PARP1/2 as imaging targets have been shown to detect, delineate, and predict therapeutic responses in many diseases by locating and quantifying the expression levels of PARP1/2. PARP1/2-directed noninvasive positron emission tomography (PET) has potential in diagnosing and prognosing neurological diseases. However, quantitative PARP PET imaging in the central nervous system (CNS) has evaded us due to the challenges of developing blood-brain barrier (BBB) penetrable PARP radioligands. Here, we review PARP1/2's relevance in CNS diseases, summarize the recent progress on PARP PET and discuss the possibilities of developing novel PARP radiotracers for CNS diseases.
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Affiliation(s)
| | | | | | | | - Zhengxin Cai
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, United States
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4
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Arruri VK, Gundu C, Khan I, Khatri DK, Singh SB. PARP overactivation in neurological disorders. Mol Biol Rep 2021; 48:2833-2841. [PMID: 33768369 DOI: 10.1007/s11033-021-06285-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 03/11/2021] [Indexed: 12/23/2022]
Abstract
Poly (ADP-ribose) polymerases (PARPs) constitute a family of enzymes associated with divergent cellular processes that are not limited to DNA repair, chromatin organization, genome integrity, and apoptosis but also found to play a crucial role in inflammation. PARPs mediate poly (ADP-ribosylation) of DNA binding proteins that is often responsible for chromatin remodeling thereby ensure effective repairing of DNA stand breaks although during the conditions of severe genotoxic stress PARPs direct the cell fate towards apoptotic events. Recent discoveries have pushed PARPs into the spotlight as targets for treating cancer, metabolic, inflammatory and neurological disorders. Of note, PARP-1 is the most abundant isoform of PARPs (18 member super family) which executes more than 90% of PARPs functions. Since oxidative/nitrosative stress actuated PARP-1 is linked to vigorous DNA damage and wide spread provocative inflammatory response that underlie the aetiopathogenesis of different neurological disorders, possibility of developing PARP-1 inhibitors as plausible neurotherapeutic agents attracts considerable research interest. This review outlines the recent advances in PARP-1 biology and examines the capability of PARP-1 inhibitors as treatment modalities in intense and interminable diseases of neuronal origin.
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Affiliation(s)
- Vijay Kumar Arruri
- Neuropharmacology Laboratory, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Balanagar, Hyderabad, Telangana, 500037, India
| | - Chayanika Gundu
- Neuropharmacology Laboratory, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Balanagar, Hyderabad, Telangana, 500037, India
| | - Islauddin Khan
- Neuropharmacology Laboratory, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Balanagar, Hyderabad, Telangana, 500037, India
| | - Dharmendra Kumar Khatri
- Neuropharmacology Laboratory, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Balanagar, Hyderabad, Telangana, 500037, India
| | - Shashi Bala Singh
- Neuropharmacology Laboratory, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Balanagar, Hyderabad, Telangana, 500037, India.
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5
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Eleutherio ECA, Silva Magalhães RS, de Araújo Brasil A, Monteiro Neto JR, de Holanda Paranhos L. SOD1, more than just an antioxidant. Arch Biochem Biophys 2020; 697:108701. [PMID: 33259795 DOI: 10.1016/j.abb.2020.108701] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 12/14/2022]
Abstract
During cellular respiration, radicals, such as superoxide, are produced, and in a large concentration, they may cause cell damage. To combat this threat, the cell employs the enzyme Cu/Zn Superoxide Dismutase (SOD1), which converts the radical superoxide into molecular oxygen and hydrogen peroxide, through redox reactions. Although this is its main function, recent studies have shown that the SOD1 has other functions that deviates from its original one including activation of nuclear gene transcription or as an RNA binding protein. This comprehensive review looks at the most important aspects of human SOD1 (hSOD1), including the structure, properties, and characteristics as well as transcriptional and post-translational modifications (PTM) that the enzyme can receive and their effects, and its many functions. We also discuss the strategies currently used to analyze it to better understand its participation in diseases linked to hSOD1 including Amyotrophic Lateral Sclerosis (ALS), cancer, and Parkinson.
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6
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Strong MJ, Donison NS, Volkening K. Alterations in Tau Metabolism in ALS and ALS-FTSD. Front Neurol 2020; 11:598907. [PMID: 33329356 PMCID: PMC7719764 DOI: 10.3389/fneur.2020.598907] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 10/27/2020] [Indexed: 12/15/2022] Open
Abstract
There is increasing acceptance that amyotrophic lateral sclerosis (ALS), classically considered a neurodegenerative disease affecting almost exclusively motor neurons, is syndromic with both clinical and biological heterogeneity. This is most evident in its association with a broad range of neuropsychological, behavioral, speech and language deficits [collectively termed ALS frontotemporal spectrum disorder (ALS-FTSD)]. Although the most consistent pathology of ALS and ALS-FTSD is a disturbance in TAR DNA binding protein 43 kDa (TDP-43) metabolism, alterations in microtubule-associated tau protein (tau) metabolism can also be observed in ALS-FTSD, most prominently as pathological phosphorylation at Thr175 (pThr175tau). pThr175 has been shown to promote exposure of the phosphatase activating domain (PAD) in the tau N-terminus with the consequent activation of GSK3β mediated phosphorylation at Thr231 (pThr231tau) leading to pathological oligomer formation. This pathological cascade of tau phosphorylation has been observed in chronic traumatic encephalopathy with ALS (CTE-ALS) and in both in vivo and in vitro experimental paradigms, suggesting that it is of critical relevance to the pathobiology of ALS-FTSD. It is also evident that the co-existence of alterations in the metabolism of TDP-43 and tau acts synergistically in a rodent model to exacerbate the pathology of either.
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Affiliation(s)
- Michael J Strong
- Molecular Medicine, Schulich School of Medicine and Dentistry, Robarts Research Institute, Western University, London, ON, Canada.,Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Neil S Donison
- Molecular Medicine, Schulich School of Medicine and Dentistry, Robarts Research Institute, Western University, London, ON, Canada.,Neuroscience Graduate Program, Western University, London, ON, Canada
| | - Kathryn Volkening
- Molecular Medicine, Schulich School of Medicine and Dentistry, Robarts Research Institute, Western University, London, ON, Canada.,Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
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7
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Da Ros M, Deol HK, Savard A, Guo H, Meiering EM, Gibbings D. Wild-type and mutant SOD1 localizes to RNA-rich structures in cells and mice but does not bind RNA. J Neurochem 2020; 156:524-538. [PMID: 32683701 DOI: 10.1111/jnc.15126] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 06/08/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022]
Abstract
Many of the genes whose mutation causes Amyotrophic Lateral Sclerosis (ALS) are RNA-binding proteins which localize to stress granules, while others impact the assembly, stability, and elimination of stress granules. This has led to the hypothesis that alterations in the dynamics of stress granules and RNA biology cause ALS. Genetic mutations in Superoxide Dismutase 1 (SOD1) also cause ALS. Evidence demonstrates that SOD1 harboring ALS-linked mutations is recruited to stress granules, induces changes in alternative splicing, and could be an RNA-binding protein. Whether SOD1 inclusions contain RNA in disease models and whether SOD1 directly binds RNA remains uncertain. We applied methods including cross-linking immunoprecipitation and in vitro gel shift assays to detect binding of SOD1 to RNA in vitro, in cells with and without stress granules, and in mice expressing human SOD1 G93A. We find that SOD1 localizes to RNA-rich structures including stress granules, and SOD1 inclusions in mice contain mRNA. However, we find no evidence that SOD1 directly binds RNA. This suggests that SOD1 may impact stress granules, alternative splicing and RNA biology without binding directly to RNA.
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Affiliation(s)
- Matteo Da Ros
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Canada.,The Eric Poulin Centre for Neuromuscular Disease, Ottawa, ON, Canada
| | - Harmeen K Deol
- Department of Chemistry, University of Waterloo, Waterloo, ON, Canada
| | - Alexandre Savard
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Canada.,The Eric Poulin Centre for Neuromuscular Disease, Ottawa, ON, Canada
| | - Huishan Guo
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Canada.,The Eric Poulin Centre for Neuromuscular Disease, Ottawa, ON, Canada
| | | | - Derrick Gibbings
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Canada.,The Eric Poulin Centre for Neuromuscular Disease, Ottawa, ON, Canada
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8
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Pourhaghighi R, Ash PEA, Phanse S, Goebels F, Hu LZM, Chen S, Zhang Y, Wierbowski SD, Boudeau S, Moutaoufik MT, Malty RH, Malolepsza E, Tsafou K, Nathan A, Cromar G, Guo H, Abdullatif AA, Apicco DJ, Becker LA, Gitler AD, Pulst SM, Youssef A, Hekman R, Havugimana PC, White CA, Blum BC, Ratti A, Bryant CD, Parkinson J, Lage K, Babu M, Yu H, Bader GD, Wolozin B, Emili A. BraInMap Elucidates the Macromolecular Connectivity Landscape of Mammalian Brain. Cell Syst 2020; 10:333-350.e14. [PMID: 32325033 PMCID: PMC7938770 DOI: 10.1016/j.cels.2020.03.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 11/25/2019] [Accepted: 03/20/2020] [Indexed: 12/12/2022]
Abstract
Connectivity webs mediate the unique biology of the mammalian brain. Yet, while cell circuit maps are increasingly available, knowledge of their underlying molecular networks remains limited. Here, we applied multi-dimensional biochemical fractionation with mass spectrometry and machine learning to survey endogenous macromolecules across the adult mouse brain. We defined a global "interactome" comprising over one thousand multi-protein complexes. These include hundreds of brain-selective assemblies that have distinct physical and functional attributes, show regional and cell-type specificity, and have links to core neurological processes and disorders. Using reciprocal pull-downs and a transgenic model, we validated a putative 28-member RNA-binding protein complex associated with amyotrophic lateral sclerosis, suggesting a coordinated function in alternative splicing in disease progression. This brain interaction map (BraInMap) resource facilitates mechanistic exploration of the unique molecular machinery driving core cellular processes of the central nervous system. It is publicly available and can be explored here https://www.bu.edu/dbin/cnsb/mousebrain/.
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Affiliation(s)
- Reza Pourhaghighi
- Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada
| | - Peter E A Ash
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
| | - Sadhna Phanse
- Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada; Department of Biochemistry, University of Regina, Regina, SK, Canada; Center for Network Systems Biology, Boston University, Boston, MA, USA
| | - Florian Goebels
- Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada
| | - Lucas Z M Hu
- Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada
| | - Siwei Chen
- Department of Biological Statistics and Computational Biology, Cornell University, Ithaca, NY, USA
| | - Yingying Zhang
- Department of Biological Statistics and Computational Biology, Cornell University, Ithaca, NY, USA
| | - Shayne D Wierbowski
- Department of Biological Statistics and Computational Biology, Cornell University, Ithaca, NY, USA
| | - Samantha Boudeau
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
| | | | - Ramy H Malty
- Department of Biochemistry, University of Regina, Regina, SK, Canada
| | - Edyta Malolepsza
- Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Broad Institute of Massachusetts Institute of Technology and Harvard University, Boston, MA, USA
| | - Kalliopi Tsafou
- Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Broad Institute of Massachusetts Institute of Technology and Harvard University, Boston, MA, USA
| | - Aparna Nathan
- Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Broad Institute of Massachusetts Institute of Technology and Harvard University, Boston, MA, USA
| | - Graham Cromar
- Program in Molecular Medicine, Hospital for Sick Children and University of Toronto, Toronto, ON, Canada
| | - Hongbo Guo
- Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada
| | - Ali Al Abdullatif
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
| | - Daniel J Apicco
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
| | - Lindsay A Becker
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - Aaron D Gitler
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - Stefan M Pulst
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
| | - Ahmed Youssef
- Program in Bioinformatics, Boston University, Boston, MA, USA; Center for Network Systems Biology, Boston University, Boston, MA, USA; Department of Biochemistry, Boston University School of Medicine, Boston University, Boston, MA, USA
| | - Ryan Hekman
- Center for Network Systems Biology, Boston University, Boston, MA, USA; Department of Biochemistry, Boston University School of Medicine, Boston University, Boston, MA, USA
| | - Pierre C Havugimana
- Center for Network Systems Biology, Boston University, Boston, MA, USA; Department of Biochemistry, Boston University School of Medicine, Boston University, Boston, MA, USA; Departments of Biochemistry and Biology, Boston University, Boston, MA, USA
| | - Carl A White
- Center for Network Systems Biology, Boston University, Boston, MA, USA; Department of Biochemistry, Boston University School of Medicine, Boston University, Boston, MA, USA
| | - Benjamin C Blum
- Center for Network Systems Biology, Boston University, Boston, MA, USA; Department of Biochemistry, Boston University School of Medicine, Boston University, Boston, MA, USA
| | - Antonia Ratti
- Department of Neurology and Laboratory of Neuroscience, IRCCS, Milan, Italy
| | - Camron D Bryant
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
| | - John Parkinson
- Program in Molecular Medicine, Hospital for Sick Children and University of Toronto, Toronto, ON, Canada
| | - Kasper Lage
- Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Broad Institute of Massachusetts Institute of Technology and Harvard University, Boston, MA, USA
| | - Mohan Babu
- Department of Biochemistry, University of Regina, Regina, SK, Canada
| | - Haiyuan Yu
- Department of Biological Statistics and Computational Biology, Cornell University, Ithaca, NY, USA
| | - Gary D Bader
- Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada
| | - Benjamin Wolozin
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA; Department of Neurology, Boston University School of Medicine, Boston, MA, USA; Program in Neuroscience, Boston University, Boston, MA, USA.
| | - Andrew Emili
- Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada; Program in Bioinformatics, Boston University, Boston, MA, USA; Center for Network Systems Biology, Boston University, Boston, MA, USA; Department of Biochemistry, Boston University School of Medicine, Boston University, Boston, MA, USA; Departments of Biochemistry and Biology, Boston University, Boston, MA, USA.
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9
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Campos-Melo D, Hawley ZCE, Strong MJ. Dysregulation of human NEFM and NEFH mRNA stability by ALS-linked miRNAs. Mol Brain 2018; 11:43. [PMID: 30029677 PMCID: PMC6054723 DOI: 10.1186/s13041-018-0386-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/03/2018] [Indexed: 12/12/2022] Open
Abstract
Neurofilaments (NFs) are the most abundant cytoskeletal component of vertebrate myelinated axons. NFs function by determining axonal caliber, promoting axonal growth and forming a 3-dimensional lattice that supports the organization of cytoplasmic organelles. The stoichiometry of NF protein subunits (NFL, NFM and NFH) has to be tightly controlled to avoid the formation of NF neuronal cytoplasmic inclusions (NCIs), axonal degeneration and neuronal death, all pathological hallmarks of amyotrophic lateral sclerosis (ALS). The post-transcriptional control of NF transcripts is critical for regulating normal levels of NF proteins. Previously, we showed that miRNAs that are dysregulated in ALS spinal cord regulate the levels of NEFL mRNA. In order to complete the understanding of altered NF expression in ALS, in this study we have investigated the regulation of NEFM and NEFH mRNA levels by miRNAs. We observed that a small group of ALS-linked miRNAs that are expressed in human spinal motor neurons directly regulate NEFM and NEFH transcript levels in a manner that is associated with an increase in NFM and NFH protein levels in ALS spinal cord homogenates. In concert with previous observations demonstrating the suppression of NEFL mRNA steady state levels in ALS, these observations provide support for the hypothesis that the dysregulation of miRNAs in spinal motor neurons in ALS fundamentally alters the stoichiometry of NF expression, leading to the formation of pathological NCIs.
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Affiliation(s)
- Danae Campos-Melo
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Zachary C E Hawley
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Michael J Strong
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada. .,Department of Pathology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada. .,Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada. .,University Hospital, LHSC, Rm C7-120, 339, Windermere Road, London, ON, N6A 5A5, Canada.
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10
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Volkening K, Keller BA, Leystra-Lantz C, Strong MJ. RNA and Protein Interactors with TDP-43 in Human Spinal-Cord Lysates in Amyotrophic Lateral Sclerosis. J Proteome Res 2018. [DOI: 10.1021/acs.jproteome.8b00126] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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11
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Uversky VN. The roles of intrinsic disorder-based liquid-liquid phase transitions in the "Dr. Jekyll-Mr. Hyde" behavior of proteins involved in amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Autophagy 2017; 13:2115-2162. [PMID: 28980860 DOI: 10.1080/15548627.2017.1384889] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Pathological developments leading to amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) are associated with misbehavior of several key proteins, such as SOD1 (superoxide dismutase 1), TARDBP/TDP-43, FUS, C9orf72, and dipeptide repeat proteins generated as a result of the translation of the intronic hexanucleotide expansions in the C9orf72 gene, PFN1 (profilin 1), GLE1 (GLE1, RNA export mediator), PURA (purine rich element binding protein A), FLCN (folliculin), RBM45 (RNA binding motif protein 45), SS18L1/CREST, HNRNPA1 (heterogeneous nuclear ribonucleoprotein A1), HNRNPA2B1 (heterogeneous nuclear ribonucleoprotein A2/B1), ATXN2 (ataxin 2), MAPT (microtubule associated protein tau), and TIA1 (TIA1 cytotoxic granule associated RNA binding protein). Although these proteins are structurally and functionally different and have rather different pathological functions, they all possess some levels of intrinsic disorder and are either directly engaged in or are at least related to the physiological liquid-liquid phase transitions (LLPTs) leading to the formation of various proteinaceous membrane-less organelles (PMLOs), both normal and pathological. This review describes the normal and pathological functions of these ALS- and FTLD-related proteins, describes their major structural properties, glances at their intrinsic disorder status, and analyzes the involvement of these proteins in the formation of normal and pathological PMLOs, with the ultimate goal of better understanding the roles of LLPTs and intrinsic disorder in the "Dr. Jekyll-Mr. Hyde" behavior of those proteins.
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Affiliation(s)
- Vladimir N Uversky
- a Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute , Morsani College of Medicine , University of South Florida , Tampa , FL , USA.,b Institute for Biological Instrumentation of the Russian Academy of Sciences , Pushchino, Moscow region , Russia
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12
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Wang H, Wu M, Zhan C, Ma E, Yang M, Yang X, Li Y. Neurofilament proteins in axonal regeneration and neurodegenerative diseases. Neural Regen Res 2015; 7:620-6. [PMID: 25745454 PMCID: PMC4346988 DOI: 10.3969/j.issn.1673-5374.2012.08.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 02/05/2012] [Indexed: 12/21/2022] Open
Abstract
Neurofilament protein is a component of the mature neuronal cytoskeleton, and it interacts with the zygosome, which is mediated by neurofilament-related proteins. Neurofilament protein regulates enzyme function and the structure of linker proteins. In addition, neurofilament gene expression plays an important role in nervous system development. Previous studies have shown that neurofilament gene transcriptional regulation is crucial for neurofilament protein expression, especially in axonal regeneration and degenerative diseases. Post-transcriptional regulation increased neurofilament protein gene transcription during axonal regeneration, ultimately resulting in a pattern of neurofilament protein expression. An expression imbalance of post-transcriptional regulatory proteins and other disorders could lead to amyotrophic lateral sclerosis or other neurodegenerative diseases. These findings indicated that after transcription, neurofilament protein regulated expression of related proteins and promoted regeneration of damaged axons, suggesting that regulation disorders could lead to neurodegenerative diseases.
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Affiliation(s)
- Haitao Wang
- Department of Spine Surgery, China-Japan Union Hospital, Jilin University, Changchun 130033, Jilin Province, China
| | - Minfei Wu
- Department of Spine Surgery, China-Japan Union Hospital, Jilin University, Changchun 130033, Jilin Province, China
| | - Chuanjun Zhan
- Department of Spine Surgery, China-Japan Union Hospital, Jilin University, Changchun 130033, Jilin Province, China
| | - Enyuan Ma
- Department of Orthopedic Surgery, Beihua University Affiliated Hospital, Jilin 132000, Jilin Province, China
| | - Maoguang Yang
- Department of Spine Surgery, China-Japan Union Hospital, Jilin University, Changchun 130033, Jilin Province, China
| | - Xiaoyu Yang
- Department of Spine Surgery, China-Japan Union Hospital, Jilin University, Changchun 130033, Jilin Province, China
| | - Yingpu Li
- Department of Spine Surgery, China-Japan Union Hospital, Jilin University, Changchun 130033, Jilin Province, China
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Zhao D, Zhang S, Meng Y, Xiongwei D, Zhang D, Liang Y, Wang L, Liu C. Polyanion binding accelerates the formation of stable and low-toxic aggregates of ALS-linked SOD1 mutant A4V. Proteins 2014; 82:3356-72. [PMID: 25220364 DOI: 10.1002/prot.24691] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Revised: 09/04/2014] [Accepted: 09/10/2014] [Indexed: 12/16/2022]
Abstract
The toxic property thus far shared by both ALS-linked SOD1 variants and wild-type SOD1 is an increased propensity to aggregation. However, whether SOD1 oligomers or aggregates are toxic to cells remains to be well defined. Moreover, how the toxic SOD1 species are removed from intra- and extracellular environments also needs to be further explored. The DNA binding has been shown to be capable of accelerating the aggregatio\n of wild-type and oxidized SOD1 forms under acidic and neutral conditions. In this study, we explore the binding of DNA and heparin, two types of essential life polyanions, to A4V, an ALS-linked SOD1 mutant, under acidic conditions, and its consequences. The polyanion binding alters the A4V conformation, neutralizes its local positive charges, and increases its local concentrations along the polyanion chain, which are sufficient to lead to acceleration of the pH-dependent A4V aggregation. The accelerated aggregation, which is ascribed to the polyanion binding-mediated removal or shortening of the lag phase in aggregation, contributes to the formation of amorphous A4V nanoparticles. The prolonged incubation with polyanions not only results in the complete conversion of likely soluble toxic A4V oligomers into non- and low-toxic SDS-resistant aggregates, but also increases their stability. Although this is only an initial step toward reducing the toxicity of SOD1 mutants, the accelerating role of polyanions in protein aggregation might become one of the rapid pathways that remove toxic forms of SOD1 mutants from intra- and extracellular environments.
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Affiliation(s)
- Dan Zhao
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education and School of Chemistry, Central China Normal University, Wuhan, 430079, China
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Droppelmann CA, Campos-Melo D, Volkening K, Strong MJ. The emerging role of guanine nucleotide exchange factors in ALS and other neurodegenerative diseases. Front Cell Neurosci 2014; 8:282. [PMID: 25309324 PMCID: PMC4159981 DOI: 10.3389/fncel.2014.00282] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 08/25/2014] [Indexed: 12/11/2022] Open
Abstract
Small GTPases participate in a broad range of cellular processes such as proliferation, differentiation, and migration. The exchange of GDP for GTP resulting in the activation of these GTPases is catalyzed by a group of enzymes called guanine nucleotide exchange factors (GEFs), of which two classes: Dbl-related exchange factors and the more recently described dedicator of cytokinesis proteins family exchange factors. Increasingly, deregulation of normal GEF activity or function has been associated with a broad range of disease states, including neurodegeneration and neurodevelopmental disorders. In this review, we examine this evidence with special emphasis on the novel role of Rho guanine nucleotide exchange factor (RGNEF/p190RhoGEF) in the pathogenesis of amyotrophic lateral sclerosis. RGNEF is the first neurodegeneration-linked GEF that regulates not only RhoA GTPase activation but also functions as an RNA binding protein that directly acts with low molecular weight neurofilament mRNA 3' untranslated region to regulate its stability. This dual role for RGNEF, coupled with the increasing understanding of the key role for GEFs in modulating the GTPase function in cell survival suggests a prominent role for GEFs in mediating a critical balance between cytotoxicity and neuroprotection which, when disturbed, contributes to neuronal loss.
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Affiliation(s)
- Cristian A Droppelmann
- Molecular Medicine Group, Robarts Research Institute, Western University London, ON, Canada
| | - Danae Campos-Melo
- Molecular Medicine Group, Robarts Research Institute, Western University London, ON, Canada
| | - Kathryn Volkening
- Molecular Medicine Group, Robarts Research Institute, Western University London, ON, Canada ; Department of Clinical Neurological Sciences, Schulich School of Medicine & Dentistry, Western University London, ON, Canada
| | - Michael J Strong
- Molecular Medicine Group, Robarts Research Institute, Western University London, ON, Canada ; Department of Clinical Neurological Sciences, Schulich School of Medicine & Dentistry, Western University London, ON, Canada
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Chen H, Qian K, Du Z, Cao J, Petersen A, Liu H, Blackbourn LW, Huang CL, Errigo A, Yin Y, Lu J, Ayala M, Zhang SC. Modeling ALS with iPSCs reveals that mutant SOD1 misregulates neurofilament balance in motor neurons. Cell Stem Cell 2014; 14:796-809. [PMID: 24704493 DOI: 10.1016/j.stem.2014.02.004] [Citation(s) in RCA: 231] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Revised: 02/12/2014] [Accepted: 02/13/2014] [Indexed: 01/12/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) presents motoneuron (MN)-selective protein inclusions and axonal degeneration but the underlying mechanisms of such are unknown. Using induced pluripotent cells (iPSCs) from patients with mutation in the Cu/Zn superoxide dismutase (SOD1) gene, we show that spinal MNs, but rarely non-MNs, exhibited neurofilament (NF) aggregation followed by neurite degeneration when glia were not present. These changes were associated with decreased stability of NF-L mRNA and binding of its 3' UTR by mutant SOD1 and thus altered protein proportion of NF subunits. Such MN-selective changes were mimicked by expression of a single copy of the mutant SOD1 in human embryonic stem cells and were prevented by genetic correction of the SOD1 mutation in patient's iPSCs. Importantly, conditional expression of NF-L in the SOD1 iPSC-derived MNs corrected the NF subunit proportion, mitigating NF aggregation and neurite degeneration. Thus, NF misregulation underlies mutant SOD1-mediated NF aggregation and axonal degeneration in ALS MNs.
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Affiliation(s)
- Hong Chen
- Department of Rehabilitation Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China; Waisman Center, University of Wisconsin, Madison, WI 53705, USA
| | - Kun Qian
- Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China; Waisman Center, University of Wisconsin, Madison, WI 53705, USA
| | - Zhongwei Du
- Waisman Center, University of Wisconsin, Madison, WI 53705, USA
| | - Jingyuan Cao
- Waisman Center, University of Wisconsin, Madison, WI 53705, USA
| | - Andrew Petersen
- Waisman Center, University of Wisconsin, Madison, WI 53705, USA
| | - Huisheng Liu
- Waisman Center, University of Wisconsin, Madison, WI 53705, USA
| | | | | | - Anthony Errigo
- Waisman Center, University of Wisconsin, Madison, WI 53705, USA
| | - Yingnan Yin
- Waisman Center, University of Wisconsin, Madison, WI 53705, USA
| | - Jianfeng Lu
- Waisman Center, University of Wisconsin, Madison, WI 53705, USA
| | - Melvin Ayala
- Waisman Center, University of Wisconsin, Madison, WI 53705, USA
| | - Su-Chun Zhang
- Waisman Center, University of Wisconsin, Madison, WI 53705, USA; Department of Neuroscience and Department of Neurology, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53705, USA.
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Ishtiaq M, Campos-Melo D, Volkening K, Strong MJ. Analysis of novel NEFL mRNA targeting microRNAs in amyotrophic lateral sclerosis. PLoS One 2014; 9:e85653. [PMID: 24454911 PMCID: PMC3893244 DOI: 10.1371/journal.pone.0085653] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 11/29/2013] [Indexed: 02/02/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal disease characterized by progressive motor neuron degeneration and neurofilament aggregate formation. Spinal motor neurons in ALS also show a selective suppression in the levels of low molecular weight neurofilament (NEFL) mRNA. We have been interested in investigating the role of microRNAs (miRNAs) in NEFL transcript stability. MiRNAs are small, 20–25 nucleotide, non-coding RNAs that act as post-transcriptional gene regulators by targeting the 3′ untranslated region (3′UTR) of mRNA resulting in mRNA decay or translational silencing. In this study, we characterized putative novel miRNAs from a small RNA library derived from control and sporadic ALS (sALS) spinal cords. We detected 80 putative novel miRNAs, 24 of which have miRNA response elements (MREs) within the NEFL mRNA 3′UTR. From this group, we determined by real-time PCR that 10 miRNAs were differentially expressed in sALS compared to controls. Functional analysis by reporter gene assay and relative quantitative RT-PCR showed that two novel miRNAs, miR-b1336 and miR-b2403, were downregulated in ALS spinal cord and that both stabilize NEFL mRNA. We confirmed the direct effect of these latter miRNAs using anit-miR-b1336 and anti-miR-b2403. These results demonstrate that the expression of two miRNAs (miRNAs miR-b1336 and miR-b2403) whose effect is to stabilize NEFL mRNA are down regulated in ALS, the net effect of which is predicted to contribute directly to the loss of NEFL steady state mRNA which is pathognomic of spinal motor neurons in ALS.
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Affiliation(s)
- Muhammad Ishtiaq
- Molecular Medicine Research Group, Robarts Research Institute, Western University, London, Ontario, Canada
| | - Danae Campos-Melo
- Molecular Medicine Research Group, Robarts Research Institute, Western University, London, Ontario, Canada
| | - Kathryn Volkening
- Molecular Medicine Research Group, Robarts Research Institute, Western University, London, Ontario, Canada
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Michael J. Strong
- Molecular Medicine Research Group, Robarts Research Institute, Western University, London, Ontario, Canada
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
- * E-mail:
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Lin PY, Simon SM, Koh WK, Folorunso O, Umbaugh CS, Pierce A. Heat shock factor 1 over-expression protects against exposure of hydrophobic residues on mutant SOD1 and early mortality in a mouse model of amyotrophic lateral sclerosis. Mol Neurodegener 2013; 8:43. [PMID: 24256636 PMCID: PMC3907013 DOI: 10.1186/1750-1326-8-43] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 11/11/2013] [Indexed: 12/13/2022] Open
Abstract
Background Mutations in the Cu/Zn superoxide dismutase gene (SOD1) are responsible for 20% of familial forms of amyotrophic lateral sclerosis (ALS), and mutant SOD1 has been shown to have increased surface hydrophobicity in vitro. Mutant SOD1 may adopt a complex array of conformations with varying toxicity in vivo. We have used a novel florescence-based proteomic assay using 4,4’-bis-1-anilinonaphthalene-8-sulfonate (bisANS) to assess the surface hydrophobicity, and thereby distinguish between different conformations, of SOD1and other proteins in situ. Results Covalent bisANS labeling of spinal cord extracts revealed that alterations in surface hydrophobicity of H46R/H48Q mutations in SOD1 provoke formation of high molecular weight SOD1 species with lowered solubility, likely due to increased exposure of hydrophobic surfaces. BisANS was docked on the H46R/H48Q SOD1 structure at the disordered copper binding and electrostatic loops of mutant SOD1, but not non-mutant WT SOD1. 16 non-SOD1 proteins were also identified that exhibited altered surface hydrophobicity in the H46R/H48Q mutant mouse model of ALS, including proteins involved in energy metabolism, cytoskeleton, signaling, and protein quality control. Heat shock proteins (HSPs) were also enriched in the detergent-insoluble fractions with SOD1. Given that chaperones recognize proteins with exposed hydrophobic surfaces as substrates and the importance of protein homeostasis in ALS, we crossed SOD1 H46R/H48Q mutant mice with mice over-expressing the heat shock factor 1 (HSF1) transcription factor. Here we showed that HSF1 over-expression in H46R/H48Q ALS mice enhanced proteostasis as evidenced by increased expression of HSPs in motor neurons and astrocytes and increased solubility of mutant SOD1. HSF1 over-expression significantly reduced body weight loss, delayed ALS disease onset, decreases cases of early disease, and increased survival for the 25th percentile in an H46R/H48Q SOD1 background. HSF1 overexpression did not affect macroautophagy in the ALS background, but was associated with maintenance of carboxyl terminus of Hsp70 interacting protein (CHIP) expression which declined in H46R/H48Q mice. Conclusion Our results uncover the potential importance of changes in protein surface hydrophobicity of SOD1 and other non-SOD1 proteins in ALS, and how strategies that activate HSF1 are valid therapies for ALS and other age-associated proteinopathies.
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Affiliation(s)
- Pei-Yi Lin
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA.
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Campos-Melo D, Droppelmann CA, He Z, Volkening K, Strong MJ. Altered microRNA expression profile in Amyotrophic Lateral Sclerosis: a role in the regulation of NFL mRNA levels. Mol Brain 2013; 6:26. [PMID: 23705811 PMCID: PMC3668997 DOI: 10.1186/1756-6606-6-26] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Accepted: 05/22/2013] [Indexed: 12/12/2022] Open
Abstract
Background Amyotrophic Lateral Sclerosis (ALS) is a progressive, adult onset, fatal neurodegenerative disease of motor neurons. There is emerging evidence that alterations in RNA metabolism may be critical in the pathogenesis of ALS. MicroRNAs (miRNAs) are small non-coding RNAs that are key determinants of mRNA stability. Considering that miRNAs are increasingly being recognized as having a role in a variety of neurodegenerative diseases, we decided to characterize the miRNA expression profile in spinal cord (SC) tissue in sporadic ALS (sALS) and controls. Furthermore, we performed functional analysis to identify a group of dysregulated miRNAs that could be responsible for the selective suppression of low molecular weight neurofilament (NFL) mRNA observed in ALS. Results Using TaqMan arrays we analyzed 664 miRNAs and found that a large number of miRNAs are differentially expressed in ventral lumbar SC in sALS compared to controls. We observed that the majority of dysregulated miRNAs are down-regulated in sALS SC tissues. Ingenuity Pathway Analysis (IPA) showed that dysregulated miRNAs are linked with nervous system function and cell death. We used two prediction algorithms to develop a panel of miRNAs that have recognition elements within the human NFL mRNA 3′UTR, and then we performed functional analysis for these miRNAs. Our results demonstrate that three miRNAs that are dysregulated in sALS (miR-146a*, miR-524-5p and miR-582-3p) are capable of interacting with NFL mRNA 3′UTR in a manner that is consistent with the suppressed steady state mRNA levels observed in spinal motor neurons in ALS. Conclusions The miRNA expression profile is broadly altered in the SC in sALS. Amongst these is a group of dysregulated miRNAs directly regulate the NFL mRNA 3′UTR, suggesting a role in the selective suppression of NFL mRNA in the ALS spinal motor neuron neurofilamentous aggregate formation.
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Affiliation(s)
- Danae Campos-Melo
- Molecular Brain Research Group, Robarts Research Institute, University of Western Ontario, London, ON, Canada
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Droppelmann CA, Wang J, Campos-Melo D, Keller B, Volkening K, Hegele RA, Strong MJ. Detection of a novel frameshift mutation and regions with homozygosis within ARHGEF28 gene in familial amyotrophic lateral sclerosis. Amyotroph Lateral Scler Frontotemporal Degener 2013; 14:444-51. [PMID: 23286752 DOI: 10.3109/21678421.2012.758288] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Rho guanine nucleotide exchange factor (RGNEF) is a novel NFL mRNA destabilizing factor that forms neuronal cytoplasmic inclusions in spinal motor neurons in both sporadic (SALS) and familial (FALS) ALS patients. Given the observation of genetic mutations in a number of mRNA binding proteins associated with ALS, including TDP-43, FUS/TLS and mtSOD1, we analysed the ARHGEF28 gene (approx. 316 kb) that encodes for RGNEF in FALS cases to determine if mutations were present. We performed genomic sequencing, copy number variation analysis using TaqMan real-time PCR and spinal motor neuron immunohistochemistry using a novel RGNEF antibody. In this limited sample of FALS cases (n=7) we identified a heterozygous mutation that is predicted to generate a premature truncated gene product. We also observed extensive regions of homozygosity in the ARHGEF28 gene in two FALS patients. In conclusion, our findings of genetic alterations in the ARHGEF28 gene in cases of FALS suggest that a more comprehensive genetic analysis would be warranted.
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Affiliation(s)
- Cristian A Droppelmann
- Molecular Brain Research Group, Robarts Research Institute , University of Western Ontario, London, Ontario
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Keller BA, Volkening K, Droppelmann CA, Ang LC, Rademakers R, Strong MJ. Co-aggregation of RNA binding proteins in ALS spinal motor neurons: evidence of a common pathogenic mechanism. Acta Neuropathol 2012; 124:733-47. [PMID: 22941224 DOI: 10.1007/s00401-012-1035-z] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 07/22/2012] [Accepted: 08/14/2012] [Indexed: 12/11/2022]
Abstract
While the pathogenesis of amyotrophic lateral sclerosis (ALS) remains to be clearly delineated, there is mounting evidence that altered RNA metabolism is a commonality amongst several of the known genetic variants of the disease. In this study, we evaluated the expression of 10 ALS-associated proteins in spinal motor neurons (MNs) in ALS patients with mutations in C9orf72 (C9orf72(GGGGCC)-ALS; n = 5), SOD1 (mtSOD1-ALS; n = 9), FUS/TLS (mtFUS/TLS-ALS; n = 2), or TARDBP (mtTDP-43-ALS; n = 2) and contrasted these to cases of sporadic ALS (sALS; n = 4) and familial ALS without known mutations (fALS; n = 2). We performed colorimetric immunohistochemistry (IHC) using antibodies against TDP-43, FUS/TLS, SOD1, C9orf72, ubiquitin, sequestosome 1 (p62), optineurin, phosphorylated high molecular weight neurofilament, peripherin, and Rho-guanine nucleotide exchange factor (RGNEF). We observed that RGNEF-immunoreactive neuronal cytoplasmic inclusions (NCIs) can co-localize with TDP-43, FUS/TLS and p62 within spinal MNs. We confirmed their capacity to interact by co-immunoprecipitations. We also found that mtSOD1-ALS cases possess a unique IHC signature, including the presence of C9orf72-immunoreactive diffuse NCIs, which allows them to be distinguished from other variants of ALS at the level of light microscopy. These findings support the hypothesis that alterations in RNA metabolism are a core pathogenic pathway in ALS. We also conclude that routine IHC-based analysis of spinal MNs may aid in the identification of families not previously suspected to harbor SOD1 mutations.
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Affiliation(s)
- Brian A Keller
- Department of Pathology, Western University, London, ON, Canada
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Ruff P, Pai RB, Storici F. Real-Time PCR-Coupled CE-SELEX for DNA Aptamer Selection. ISRN MOLECULAR BIOLOGY 2012; 2012:939083. [PMID: 27335672 PMCID: PMC4890860 DOI: 10.5402/2012/939083] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 06/17/2012] [Indexed: 11/23/2022]
Abstract
Aptamers are short nucleic acid or peptide sequences capable of binding to a target molecule with high specificity and affinity. Also known as “artificial antibodies,” aptamers provide many advantages over antibodies. One of the major hurdles to aptamer isolation is the initial time and effort needed for selection. The systematic evolution of ligands by exponential enrichment (SELEX) is the traditional procedure for generating aptamers, but this process is lengthy and requires a large quantity of target and starting aptamer library. A relatively new procedure for generating aptamers using capillary electrophoresis (CE), known as CE-SELEX, is faster and more efficient than SELEX but requires laser-induced fluorescence (LIF) to detect the aptamer-target complexes. Here, we implemented an alternative system without LIF using real-time- (RT-) PCR to indirectly measure aptamer-target complexes. In three rounds of selection, as opposed to ten or more rounds common in SELEX protocols, a specific aptamer for bovine serum albumin (BSA) was obtained. The specificity of the aptamer to BSA was confirmed by electrophoretic mobility shift assays (EMSAs), an unlabeled competitor assay, and by a supershift assay. The system used here provides a cost effective and a highly efficient means of generating aptamers.
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Affiliation(s)
- Patrick Ruff
- School of Biology, Georgia Institute of Technology, 310 Ferst Drive, Atlanta, GA 30332, USA
| | - Rekha B Pai
- School of Biology, Georgia Institute of Technology, 310 Ferst Drive, Atlanta, GA 30332, USA
| | - Francesca Storici
- School of Biology, Georgia Institute of Technology, 310 Ferst Drive, Atlanta, GA 30332, USA
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Redler RL, Dokholyan NV. The complex molecular biology of amyotrophic lateral sclerosis (ALS). PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 107:215-62. [PMID: 22482452 DOI: 10.1016/b978-0-12-385883-2.00002-3] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disorder that causes selective death of motor neurons followed by paralysis and death. A subset of ALS cases is caused by mutations in the gene for Cu, Zn superoxide dismutase (SOD1), which impart a toxic gain of function to this antioxidant enzyme. This neurotoxic property is widely believed to stem from an increased propensity to misfold and aggregate caused by decreased stability of the native homodimer or a tendency to lose stabilizing posttranslational modifications. Study of the molecular mechanisms of SOD1-related ALS has revealed a complex array of interconnected pathological processes, including glutamate excitotoxicity, dysregulation of neurotrophic factors and axon guidance proteins, axonal transport defects, mitochondrial dysfunction, deficient protein quality control, and aberrant RNA processing. Many of these pathologies are directly exacerbated by misfolded and aggregated SOD1 and/or cytosolic calcium overload, suggesting the primacy of these events in disease etiology and their potential as targets for therapeutic intervention.
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Affiliation(s)
- Rachel L Redler
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA
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Droppelmann CA, Keller BA, Campos-Melo D, Volkening K, Strong MJ. Rho guanine nucleotide exchange factor is an NFL mRNA destabilizing factor that forms cytoplasmic inclusions in amyotrophic lateral sclerosis. Neurobiol Aging 2012; 34:248-62. [PMID: 22835604 DOI: 10.1016/j.neurobiolaging.2012.06.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 05/26/2012] [Accepted: 06/24/2012] [Indexed: 12/14/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is an adult-onset progressive disorder of unknown etiology characterized by the selective degeneration of motor neurons. Recent evidence supports the hypothesis that alterations in RNA metabolism in motor neurons can explain the development of protein inclusions, including neurofilamentous aggregates, observed in this pathology. In mice, p190RhoGEF, a guanine nucleotide exchange factor, is involved in neurofilament protein aggregation in an RNA-triggered transgenic model of motor neuron disease. Here, we observed that rho guanine nucleotide exchange factor (RGNEF), the human homologue of p190RhoGEF, binds low molecular weight neurofilament mRNA and affects its stability via 3' untranslated region destabilization. We observed that the overexpression of RGNEF in a stable cell line significantly decreased the level of low molecular weight neurofilament protein. Furthermore, we observed RGNEF cytoplasmic inclusions in ALS spinal motor neurons that colocalized with ubiquitin, p62/sequestosome-1, and TAR (trans-active regulatory) DNA-binding protein 43 (TDP-43). Our results provide further evidence that RNA metabolism pathways are integral to ALS pathology. This is also the first described link between ALS and an RNA binding protein with aggregate formation that is also a central cell signaling pathway molecule.
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Affiliation(s)
- Cristian A Droppelmann
- Molecular Brain Research Group, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
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From Transcriptome to Noncoding RNAs: Implications in ALS Mechanism. Neurol Res Int 2012; 2012:278725. [PMID: 22778949 PMCID: PMC3385659 DOI: 10.1155/2012/278725] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 04/27/2012] [Accepted: 05/11/2012] [Indexed: 12/12/2022] Open
Abstract
In the last years, numerous studies have focused on understanding the metabolism of RNA and its implication in disease processes but abnormal RNA metabolism is still unknown. RNA plays a central role in translating genetic information into proteins and in many other catalytic and regulatory tasks. Recent advances in the study of RNA metabolism revealed complex pathways for the generation and maintenance of functional RNA in amyotrophic lateral sclerosis (ALS). Interestingly, perturbations in RNA processing have been described in ALS at various levels such as gene transcription, mRNA stabilization, transport, and translational regulations. In this paper, we will discuss the alteration of RNA profile in ALS disease, starting from transcription, the first step leading to gene expression, through the posttranscriptional regulation, including RNA/DNA binding proteins and aberrant exon splicing to protein noncoding RNAs, as lncRNA and microRNA.
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Strong MJ, Volkening K. TDP-43 and FUS/TLS: sending a complex message about messenger RNA in amyotrophic lateral sclerosis? FEBS J 2011; 278:3569-77. [DOI: 10.1111/j.1742-4658.2011.08277.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Glial nuclear aggregates of superoxide dismutase-1 are regularly present in patients with amyotrophic lateral sclerosis. Acta Neuropathol 2011; 121:623-34. [PMID: 21287393 PMCID: PMC3085063 DOI: 10.1007/s00401-011-0805-3] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 01/20/2011] [Accepted: 01/22/2011] [Indexed: 01/19/2023]
Abstract
The most common cause of amyotrophic lateral sclerosis (ALS) is mutations in superoxide dismutase-1 (SOD1). Since there is evidence for the involvement of non-neuronal cells in ALS, we searched for signs of SOD1 abnormalities focusing on glia. Spinal cords from nine ALS patients carrying SOD1 mutations, 51 patients with sporadic or familial ALS who lacked such mutations, and 46 controls were examined by immunohistochemistry. A set of anti-peptide antibodies with specificity for misfolded SOD1 species was used. Misfolded SOD1 in the form of granular aggregates was regularly detected in the nuclei of ventral horn astrocytes, microglia, and oligodendrocytes in ALS patients carrying or lacking SOD1 mutations. There was negligible staining in neurodegenerative and non-neurological controls. Misfolded SOD1 appeared occasionally also in nuclei of motoneurons of ALS patients. The results suggest that misfolded SOD1 present in glial and motoneuron nuclei may generally be involved in ALS pathogenesis.
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Szaro BG, Strong MJ. Regulation of Cytoskeletal Composition in Neurons: Transcriptional and Post-transcriptional Control in Development, Regeneration, and Disease. ADVANCES IN NEUROBIOLOGY 2011. [DOI: 10.1007/978-1-4419-6787-9_24] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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Liu C, Zhang Y. Nucleic acid-mediated protein aggregation and assembly. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2011; 84:1-40. [DOI: 10.1016/b978-0-12-386483-3.00005-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Yin J, Hu S, Jiang W, Liu L, Lan S, Song X, Liu C. DNA-triggered aggregation of copper, zinc superoxide dismutase in the presence of ascorbate. PLoS One 2010; 5:e12328. [PMID: 20808835 PMCID: PMC2924893 DOI: 10.1371/journal.pone.0012328] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 08/02/2010] [Indexed: 11/18/2022] Open
Abstract
The oxidative damage hypothesis proposed for the function gain of copper, zinc superoxide dismutase (SOD1) maintains that both mutant and wild-type (WT) SOD1 catalyze reactions with abnormal substrates that damage cellular components critical for viability of the affected cells. However, whether the oxidative damage of SOD1 is involved in the formation of aggregates rich in SOD1 or not remains elusive. Here, we sought to explore the oxidative aggregation of WT SOD1 exposed to environments containing both ascorbate (Asc) and DNA under neutral conditions. The results showed that the WT SOD1 protein was oxidized in the presence of Asc. The oxidation results in the higher affinity of the modified protein for DNA than that of the unmodified protein. The oxidized SOD1 was observed to be more prone to aggregation than the WT SOD1, and the addition of DNA can significantly accelerate the oxidative aggregation. Moreover, a reasonable relationship can be found between the oxidation, increased hydrophobicity, and aggregation of SOD1 in the presence of DNA. The crucial step in aggregation is neutralization of the positive charges on some SOD1 surfaces by DNA binding. This study might be crucial for understanding molecular forces driving the protein aggregation.
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Affiliation(s)
- Jun Yin
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, and School of Chemistry, Central China Normal University, Wuhan, China
| | - Si Hu
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, and School of Chemistry, Central China Normal University, Wuhan, China
| | - Wei Jiang
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, and School of Chemistry, Central China Normal University, Wuhan, China
| | - Liang Liu
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, and School of Chemistry, Central China Normal University, Wuhan, China
| | - Shemin Lan
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, and School of Chemistry, Central China Normal University, Wuhan, China
| | - Xuegang Song
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, and School of Chemistry, Central China Normal University, Wuhan, China
| | - Changlin Liu
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, and School of Chemistry, Central China Normal University, Wuhan, China
- * E-mail:
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Volkening K, Leystra-Lantz C, Strong MJ. Human low molecular weight neurofilament (NFL) mRNA interacts with a predicted p190RhoGEF homologue (RGNEF) in humans. ACTA ACUST UNITED AC 2010; 11:97-103. [PMID: 19488899 DOI: 10.3109/17482960902995584] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In the mouse, p190RhoGEF is a low molecular weight neurofilament (NFL) mRNA stability factor that is involved in NF aggregate formation in neurons. A human homologue of this protein has not been described. Our objective was to identify a human homologue of p190RhoGEF, and to determine its interaction with human NFL mRNA. We used sequence homology searches to predict a human homologue (RGNEF), and RT-PCR to determine the expression of mRNA in ALS and neuropathologically normal control tissues. Gel shift assays determined the interaction of RGNEF with human NFL mRNA in vitro, while IP-RT-PCR and gel shift assays were used to confirm the interaction in tissue lysates. We determined that RGNEF is a human homologue of p190RhoGEF, and that its RNA is expressed in both brain and spinal cord. While RGNEF and NFL mRNA interact directly in vitro, interestingly they only appear to interact in ALS lysates and not in controls. These data add another player to the family of NFL mRNA stability regulators, and raise the intriguing possibility that the mechanism by which p190RhoGEF contributes to murine neuronal NF aggregate formation may be important to human ALS NF aggregate formation.
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Abstract
Motor neurons are large, highly polarised cells with very long axons and a requirement for precise spatial and temporal gene expression. Neurodegenerative disorders characterised by selective motor neuron vulnerability include various forms of amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA). A rapid expansion in knowledge on the pathophysiology of motor neuron degeneration has occurred in recent years, largely through the identification of genes leading to familial forms of ALS and SMA. The major emerging theme is that motor neuron degeneration can result from mutation in genes that encode factors important for ribonucleoprotein biogenesis and RNA processing, including splicing regulation, transcript stabilisation, translational repression and localisation of mRNA. Complete understanding of how these pathways interact and elucidation of specialised mechanisms for mRNA targeting and processing in motor neurons are likely to produce new targets for therapy in ALS and related disorders.
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RNA processing pathways in amyotrophic lateral sclerosis. Neurogenetics 2010; 11:275-90. [PMID: 20349096 DOI: 10.1007/s10048-010-0239-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Accepted: 02/24/2010] [Indexed: 12/12/2022]
Abstract
RNA processing is a tightly regulated, highly complex pathway which includes RNA transcription, pre-mRNA splicing, editing, transportation, translation, and degradation of RNA. Over the past few years, several RNA processing genes have been shown to be mutated or genetically associated with amyotrophic lateral sclerosis (ALS), including the RNA-binding proteins TDP-43 and FUS/TLS. These findings suggest that RNA processing may represent a common pathogenic mechanism involved in development of ALS. In this review, we will discuss six ALS-related, RNA processing genes including their discovery, function, and commonalities.
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RNA metabolism and the pathogenesis of motor neuron diseases. Trends Neurosci 2010; 33:249-58. [PMID: 20227117 DOI: 10.1016/j.tins.2010.02.003] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 02/09/2010] [Accepted: 02/12/2010] [Indexed: 12/11/2022]
Abstract
The pathogenic mechanisms of degenerative diseases of the nervous system are not well understood. Recent evidence suggests that proteins with a role in RNA synthesis, processing, function and degradation play a role in the mechanism of degenerative disorders affecting the motor neuron. However, most of these proteins also affect cellular processes other than RNA processing. Furthermore, many of the familial diseases are inherited dominantly, suggesting a gain-of-function as their pathogenic mechanism. This newly gained function could be unrelated to their normal role in the cell. Therefore, here we review some of the recent data linking RNA metabolism and motor neuron disorders, but also critically assess their relevance for our understanding of the mechanism of neurodegeneration.
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Barber SC, Shaw PJ. Oxidative stress in ALS: key role in motor neuron injury and therapeutic target. Free Radic Biol Med 2010; 48:629-41. [PMID: 19969067 DOI: 10.1016/j.freeradbiomed.2009.11.018] [Citation(s) in RCA: 425] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 10/16/2009] [Accepted: 11/29/2009] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder characterized by death of motor neurons leading to muscle wasting, paralysis, and death, usually within 2-3 years of symptom onset. The causes of ALS are not completely understood, and the neurodegenerative processes involved in disease progression are diverse and complex. There is substantial evidence implicating oxidative stress as a central mechanism by which motor neuron death occurs, including elevated markers of oxidative damage in ALS patient spinal cord and cerebrospinal fluid and mutations in the antioxidant enzyme superoxide dismutase 1 (SOD1) causing approximately 20% of familial ALS cases. However, the precise mechanism(s) by which mutant SOD1 leads to motor neuron degeneration has not been defined with certainty, and the ultimate trigger for increased oxidative stress in non-SOD1 cases remains unclear. Although some antioxidants have shown potential beneficial effects in animal models, human clinical trials of antioxidant therapies have so far been disappointing. Here, the evidence implicating oxidative stress in ALS pathogenesis is reviewed, along with how oxidative damage triggers or exacerbates other neurodegenerative processes, and we review the trials of a variety of antioxidants as potential therapies for ALS.
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Affiliation(s)
- Siân C Barber
- Academic Neurology Unit and Sheffield Care & Research Centre for Motor Neuron Disorders, Department of Neuroscience, University of Sheffield, Sheffield S10 2RX, UK
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37
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Szaro BG, Strong MJ. Post-transcriptional control of neurofilaments: New roles in development, regeneration and neurodegenerative disease. Trends Neurosci 2010; 33:27-37. [DOI: 10.1016/j.tins.2009.10.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2009] [Revised: 09/21/2009] [Accepted: 10/06/2009] [Indexed: 12/17/2022]
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Lunn JS, Sakowski SA, Kim B, Rosenberg AA, Feldman EL. Vascular endothelial growth factor prevents G93A-SOD1-induced motor neuron degeneration. Dev Neurobiol 2009; 69:871-84. [PMID: 19672955 PMCID: PMC2853013 DOI: 10.1002/dneu.20747] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disorder characterized by selective loss of motor neurons (MNs). Twenty percent of familial ALS cases are associated with mutations in Cu(2+)/Zn(2+) superoxide dismutase (SOD1). To specifically understand the cellular mechanisms underlying mutant SOD1 toxicity, we have established an in vitro model of ALS using rat primary MN cultures transfected with an adenoviral vector encoding a mutant SOD1, G93A-SOD1. Transfected cells undergo axonal degeneration and alterations in biochemical responses characteristic of cell death such as activation of caspase-3. Vascular endothelial growth factor (VEGF) is an angiogenic and neuroprotective growth factor that can increase axonal outgrowth, block neuronal apoptosis, and promote neurogenesis. Decreased VEGF gene expression in mice results in a phenotype similar to that seen in patients with ALS, thus linking loss of VEGF to the pathogenesis of MN degeneration. Decreased neurotrophic signals prior to and during disease progression may increase MN susceptibility to mutant SOD1-induced toxicity. In this study, we demonstrate a decrease in VEGF and VEGFR2 levels in the spinal cord of G93A-SOD1 ALS mice. Furthermore, in isolated MN cultures, VEGF alleviates the effects of G93A-SOD1 toxicity and neuroprotection involves phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling. Overall, these studies validate the usefulness of VEGF as a potential therapeutic factor for the treatment of ALS and give valuable insight into the responsible signaling pathways and mechanisms involved.
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Affiliation(s)
- J. Simon Lunn
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Stacey A. Sakowski
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Bhumsoo Kim
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Eva L. Feldman
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
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Strong MJ. The evidence for altered RNA metabolism in amyotrophic lateral sclerosis (ALS). J Neurol Sci 2009; 288:1-12. [PMID: 19840884 DOI: 10.1016/j.jns.2009.09.029] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 08/27/2009] [Accepted: 09/25/2009] [Indexed: 12/11/2022]
Abstract
In this review, the role of aberrant RNA metabolism in ALS is examined, including the evidence that a majority of the genetic mutations observed in familial ALS (including mutations in TDP-43, FUS/TLS, SOD1, angiogenin (ANG) and senataxin (SETX)) can impact directly on either gene transcription, pre-mRNA splicing, ribonucleoprotein complex formation, transport, RNA translation or degradation. The evidence that perturbed expression or function of RNA binding proteins is causally related to the selective suppression of the low molecular weight subunit protein (NFL) steady state mRNA levels in degenerating motor neurons in ALS is examined. The discovery that mtSOD1, TDP-43 and 14-3-3 proteins, all of which form cytosolic aggregates in ALS, can each modulate the stability of NFL mRNA, suggests that a fundamental alteration in the interaction of mRNA species with key trans-acting binding factors has occurred in ALS. These observations lead directly to the hypothesis that ALS can be viewed as a disorder of RNA metabolism, thus providing a novel pathway for the development of molecular pharmacotherapies.
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Affiliation(s)
- Michael J Strong
- Molecular Brain Research Group, Robarts Research Institute, London, Ontario, Canada.
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40
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Volkening K, Leystra-Lantz C, Yang W, Jaffee H, Strong MJ. Tar DNA binding protein of 43 kDa (TDP-43), 14-3-3 proteins and copper/zinc superoxide dismutase (SOD1) interact to modulate NFL mRNA stability. Implications for altered RNA processing in amyotrophic lateral sclerosis (ALS). Brain Res 2009; 1305:168-82. [PMID: 19815002 DOI: 10.1016/j.brainres.2009.09.105] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Revised: 09/28/2009] [Accepted: 09/29/2009] [Indexed: 10/20/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurological disease characterized by progressive motor neuron degeneration in association with neurofilament (NF) aggregate formation. This process is accompanied by an alteration in the stoichiometry of NF subunit protein expression such that the steady state levels of the low molecular weight NF (NFL) mRNA levels are selectively suppressed. We have previously shown that each of TDP-43, 14-3-3 and mutant SOD1 can function as NFL mRNA 3'UTR binding proteins that directly affect the stability of NFL transcripts. In this study, we demonstrate that the interaction of TDP-43 with the NFL mRNA 3' UTR involves ribonucleotide (UG) motifs present on stem loops of the 3'UTR as well as the RRM1 and RRM2 motifs of TDP-43. Ex vivo, TDP-43, 14-3-3 and SOD1 proteins interact to modulate NFL mRNA stability, although in vivo, only TDP-43 and either mutant or wild-type SOD1 co-localize in ALS motor neurons. TDP-43 was observed to co-localize to RNA transport granules (Staufen immunoreactive) in both control and ALS spinal motor neurons. In contrast, both stress granules (TIA-1 immunoreactive) and processing bodies (P-bodies; XRN-1 immunoreactive) were more prevalent in ALS motor neurons than in controls and demonstrated strong co-localization with TDP-43. Using RNA-IP-PCR, we further demonstrate that NFL mRNA is preferentially sequestered to both stress granules and P-bodies in ALS. These data suggest that NFL mRNA processing is fundamentally altered in ALS spinal motor neurons to favour compartmentalization within both stress granules and P-bodies, and that TDP-43 plays a fundamental role in this process.
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Affiliation(s)
- Kathryn Volkening
- Molecular Brain Research Group, Robarts Research Institute, 100 Perth Drive, London, Ontario, Canada N6A 5K8
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41
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Moisse K, Mepham J, Volkening K, Welch I, Hill T, Strong MJ. Cytosolic TDP-43 expression following axotomy is associated with caspase 3 activation in NFL-/- mice: support for a role for TDP-43 in the physiological response to neuronal injury. Brain Res 2009; 1296:176-86. [PMID: 19619516 DOI: 10.1016/j.brainres.2009.07.023] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 07/07/2009] [Accepted: 07/08/2009] [Indexed: 12/12/2022]
Abstract
TAR DNA binding protein (TDP-43) mislocalization has been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). We have recently reported that TDP-43 and PGRN expression is altered in response to axotomy in C57BL6 mice and that normal expression is restored following recovery. We have performed axotomies in two different presymptomatic models of motor neuron degeneration, low molecular weight neurofilament knockout (NFL(-/-)) mice and mutant SOD1(G93A) transgenic (mtSOD1(G93A)) mice aged 6 weeks, and observed TDP-43 and PGRN expression patterns in axotomized spinal motor neurons over 28 days. In contrast to both C57BL6 mice and mtSOD1(G93A) mice, behavioural deficits in NFL(-/-) mice were sustained. We did not observe differences in TDP-43 or PGRN expression between C57BL6 mice and mtSOD1(G93A) mice throughout the observation period. However, compared to C57BL6 mice and mtSOD1(G93A) mice, NFL(-/-) mice exhibited late upregulation of cytosolic TDP-43 expression and persistent downregulation of neuronal PGRN expression accompanied by caspase 3 activation on post-injury day 28. By post-injury day 42, no cytosolic TDP-43-positive neurons remained in NFL(-/-) mice, suggesting that they had undergone apoptotic cell death. These findings suggest that whereas TDP-43 expression is normally upregulated transiently following axotomy, in the absence of NFL this response is delayed and associated with caspase 3 activation and neuronal death. These results further support that TDP-43 is involved in neurofilament mRNA metabolism and transport, and provide insight into the pathogenesis of motor neuron death in ALS in which NFL mRNA levels are selectively suppressed.
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Affiliation(s)
- Katie Moisse
- Molecular Brain Research Group, Robarts Research Institute, PO Box 5015, 100 Perth Drive, London ON, Canada
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Abstract
The causes of amyotrophic lateral sclerosis (ALS) are poorly understood. A small proportion, about 2%, is associated with a mutation in the superoxide dismutase (SOD1) gene, and mice expressing this mutant gene exhibit a progressive, ALS-like neurodegenerative disease. Studies of these animals, as well as of human post mortem tissue, reveal the presence of multiple pathological processes, including oxidative stress, glutamate excitotoxicity, neuroinflammation, mitochondrial degeneration, alterations in neurofilaments and neurotubules, mitochondrial damage, aggregation of proteins, abnormalities in growth factors, and apoptosis. We propose that alterations in the disposition of zinc ions may be important in the initiation and development of ALS. SOD1 binds zinc, and many of the mutant forms of this enzyme associated with ALS show altered zinc binding. Alterations in the expression of metallothioneins (MTs), which regulate cellular levels of zinc, have been reported in mutant SOD1 mice, and deletion of MTs in these animals accelerates disease progression. Zinc plays a key role in all the pathological processes associated with ALS. Our zinc hypothesis also may help explain evidence for environmental factors in some cases of ALS, such as in the Chamorro tribe in Guam and in the Gulf War.
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Affiliation(s)
- Andrew P Smith
- The Forbes Norris ALS Research Center, California Pacific Medical Center Research Institute, California 94115, USA
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43
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Perrot R, Eyer J. Neuronal intermediate filaments and neurodegenerative disorders. Brain Res Bull 2009; 80:282-95. [PMID: 19539727 DOI: 10.1016/j.brainresbull.2009.06.004] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Revised: 06/05/2009] [Accepted: 06/05/2009] [Indexed: 12/12/2022]
Abstract
Intermediate filaments represent the most abundant cytoskeletal element in mature neurons. Mutations and/or accumulations of neuronal intermediate filament proteins are frequently observed in several human neurodegenerative disorders. Although it is now admitted that disorganization of the neurofilament network may be directly involved in neurodegeneration, certain type of perikaryal intermediate filament aggregates confer protection in motor neuron disease. The use of various mouse models provided a better knowledge of the role played by the disorganization of intermediate filaments in the pathogenesis of neurodegenerative disorders, but the mechanisms leading to the formation of these aggregates remain elusive. Here, we will review some neurodegenerative diseases involving intermediate filaments abnormalities and possible mechanisms susceptible to provoke them.
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Affiliation(s)
- Rodolphe Perrot
- Department of Anatomy and Physiology of Laval University, Centre de Recherche du Centre Hospitalier Universitaire de Québec, Quebec, Canada
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Sakowski SA, Schuyler AD, Feldman EL. Insulin-like growth factor-I for the treatment of amyotrophic lateral sclerosis. ACTA ACUST UNITED AC 2009; 10:63-73. [PMID: 18608100 DOI: 10.1080/17482960802160370] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that affects both upper and lower motorneurons (MN) resulting in weakness, paralysis and subsequent death. Insulin-like growth factor-I (IGF-I) is a potent neurotrophic factor that has neuroprotective properties in the central and peripheral nervous systems. Due to the efficacy of IGF-I in the treatment of other diseases and its ability to promote neuronal survival, IGF-I is being extensively studied in ALS therapeutic trials. This review covers in vitro and in vivo studies examining the efficacy of IGF-I in ALS model systems and also addresses the mechanisms by which IGF-I asserts its effects in these models, the status of the IGF-I system in ALS patients, results of clinical trials, and the need for the development of better delivery mechanisms to maximize IGF-I efficacy. The knowledge obtained from these studies suggests that IGF-I has the potential to be a safe and efficacious therapy for ALS.
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Affiliation(s)
- Stacey A Sakowski
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA
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45
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Li X, Lu L, Bush DJ, Zhang X, Zheng L, Suswam EA, King PH. Mutant copper-zinc superoxide dismutase associated with amyotrophic lateral sclerosis binds to adenine/uridine-rich stability elements in the vascular endothelial growth factor 3'-untranslated region. J Neurochem 2009; 108:1032-44. [PMID: 19196430 DOI: 10.1111/j.1471-4159.2008.05856.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Vascular endothelial growth factor (VEGF) is a neurotrophic factor essential for maintenance of motor neurons. Loss of this factor produces a phenotype similar to amyotrophic lateral sclerosis (ALS). We recently showed that ALS-producing mutations of Cu/Zn-superoxide dismutase (SOD1) disrupt post-transcriptional regulation of VEGF mRNA, leading to significant loss of expression [Lu et al., J. Neurosci.27 (2007), 7929]. Mutant SOD1 was present in the ribonucleoprotein complex associated with adenine/uridine-rich elements (ARE) of the VEGF 3'-untranslated region (UTR). Here, we show by electrophoretic mobility shift assay that mutant SOD1 bound directly to the VEGF 3'-UTR with a predilection for AREs similar to the RNA stabilizer HuR. SOD1 mutants A4V and G37R showed higher affinity for the ARE than L38V or G93A. Wild-type SOD1 bound very weakly with an apparent K(d) 11- to 72-fold higher than mutant forms. Mutant SOD1 showed an additional lower shift with VEGF ARE that was accentuated in the metal-free state. A similar pattern of binding was observed with AREs of tumor necrosis factor-alpha and interleukin-8, except only a single shift predominated. Using an ELISA-based assay, we demonstrated that mutant SOD1 competes with HuR and neuronal HuC for VEGF 3'-UTR binding. To define potential RNA-binding domains, we truncated G37R, G93A and wild-type SOD1 and found that peptides from the N-terminal portion of the protein that included amino acids 32-49 could recapitulate the binding pattern of full-length protein. Thus, the strong RNA-binding affinity conferred by ALS-associated mutations of SOD1 may contribute to the post-transcriptional dysregulation of VEGF mRNA.
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Affiliation(s)
- Xuelin Li
- Department of Neurology, University of Alabama at Birmingham, Alabama, USA
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46
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Turner BJ, Parkinson NJ, Davies KE, Talbot K. Survival motor neuron deficiency enhances progression in an amyotrophic lateral sclerosis mouse model. Neurobiol Dis 2009; 34:511-7. [PMID: 19332122 DOI: 10.1016/j.nbd.2009.03.005] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Revised: 02/24/2009] [Accepted: 03/18/2009] [Indexed: 11/25/2022] Open
Abstract
Mutations in the ubiquitously expressed survival motor neuron 1 (SMN1) and superoxide dismutase 1 (SOD1) genes are selectively lethal to motor neurons in spinal muscular atrophy (SMA) and familial amyotrophic lateral sclerosis (ALS), respectively. Genetic association studies provide compelling evidence that SMN1 and SMN2 genotypes encoding lower SMN protein levels are implicated in sporadic ALS, suggesting that SMN expression is a potential determinant of ALS severity. We therefore sought genetic evidence of SMN involvement in ALS by generating transgenic mutant SOD1 mice on an Smn deficient background. Partial genetic disruption of Smn significantly worsened motor performance and survival in transgenic SOD1(G93A) mice. Furthermore, ALS-linked mutant SOD1 expression severely reduced SMN protein levels, but not transcript, in neuronal culture and mouse models from early presymptomatic disease. SMN protein depletion was linked to the nuclear compartment and a physical interaction between SMN and mutant SOD1 was confirmed in mouse spinal cord. Treatment with the environmental toxin paraquat also depleted SMN protein, implicating oxidative stress in the mechanism underlying SMN deficiency in familial ALS and potentially sporadic disease. In contrast, transgenic SOD1(WT) overexpression in SMA type I mice was incapable of modulating SMN protein levels or disease progression. These data establish that SMN deficiency accelerates phenotypic severity in transgenic familial ALS mice, consistent with an enhancing genetic modifier role. We therefore propose that SMN replacement and upregulation strategies considered for SMA therapy may have protective potential for ALS.
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Affiliation(s)
- Bradley J Turner
- MRC Functional Genomics Unit, University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, UK
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47
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Ananthakrishnan L, Szaro BG. Transcriptional and translational dynamics of light neurofilament subunit RNAs during Xenopus laevis optic nerve regeneration. Brain Res 2008; 1250:27-40. [PMID: 19027722 DOI: 10.1016/j.brainres.2008.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Revised: 10/24/2008] [Accepted: 11/01/2008] [Indexed: 12/01/2022]
Abstract
Neurofilaments (NFs), which comprise one of three cytoskeletal polymers of vertebrate axons, are heteropolymers of multiple NF subunit proteins. During Xenopus laevis optic nerve regeneration, NF subunit composition undergoes progressive changes that correlate with regenerative success. Understanding the relative contributions of transcriptional and post-transcriptional gene regulatory mechanisms to these changes should therefore provide insights into the control of the axonal growth program. Previously, we examined this issue with respect to the medium neurofilament protein (NF-M). Because the integrity of NF heteropolymers depends upon maintaining properly balanced expression among multiple subunits, we have now extended this analysis to include the four light NF subunits - peripherin, the light NF triplet protein (NF-L), and two additional alpha-internexin-like proteins. Within 3 days after an optic nerve crush injury to one eye, primary transcript levels of NF subunits increased in both eyes. Levels of mRNA, however, increased in only the operated eye and did so later than did increases in primary transcript, indicating that mRNA levels are under significant post-transcriptional regulation. As measured by polysome profiling, the translational efficiencies of individual NF subunit mRNAs also shifted throughout regeneration, with operated eye mRNAs being generally more translationally active than those of unoperated eyes. Also, in operated eyes, the precise mix of efficiently and poorly translated messages throughout regeneration varied independently for each subunit, indicating that their translations are fine-tuned separately. These results suggest a model whereby traumatic disruption of visual circuitry leads to increased expression of NF primary transcripts in both eyes. These increases are subsequently modulated post-transcriptionally to accommodate shifting demands at each phase of regeneration for NF heteropolymers of differing composition in regrowing axons.
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48
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Cook C, Zhang YJ, Xu YF, Dickson DW, Petrucelli L. TDP-43 in neurodegenerative disorders. Expert Opin Biol Ther 2008; 8:969-78. [PMID: 18549326 DOI: 10.1517/14712598.8.7.969] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND The number of neurodegenerative diseases associated with pathological aggregates of transactivation response element (TAR)-DNA-binding protein 43 (TDP-43) has increased, leading to the new designation 'TDP-43 proteinopathy.' Biochemically, TDP-43 proteinopathies are characterized by decreased solubility, hyperphosphorylation, and cleavage of TDP-43 into 25- and 35-kDa fragments, and by altered cellular localization. OBJECTIVE This review summarizes research characterizing the distribution of TDP-43 pathology in human postmortem brain tissue and discusses possible therapeutic strategies based on genetic and in vitro studies. METHODS We reviewed recent studies of TDP-43 proteinopathy. RESULTS/CONCLUSION Given that several different mutations can lead to TDP-43 proteinopathies, including mutations in progranulin and valosin-containing protein, research is needed to decipher and potentially exploit the link between these mutations and TDP-43 pathology.
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Affiliation(s)
- Casey Cook
- Mayo Clinic, 4500 San Pablo Road Jacksonville, Florida 32224, USA
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Brenner S. Superoxide dismutase may lead to cytoskeletal abnormalities and amyotrophic lateral sclerosis. Ann Neurol 2008; 64:357-8; author reply 358. [PMID: 18409199 DOI: 10.1002/ana.21387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Zetterberg H, Jacobsson J, Rosengren L, Blennow K, Andersen PM. Cerebrospinal fluid neurofilament light levels in amyotrophic lateral sclerosis: impact ofSOD1genotype. Eur J Neurol 2007; 14:1329-33. [PMID: 17903209 DOI: 10.1111/j.1468-1331.2007.01972.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative syndrome with familial and sporadic forms. Most ALS-associated mutations are found in the superoxide dismutase 1 (SOD1) gene. We conducted a study including 60 sporadic and 19 familial ALS patients, 206 reference patients with other neurological disorders and 40 age- and sex-matched healthy controls to test the hypothesis that cerebrospinal fluid (CSF) levels of neurofilament light (NF-L) protein, a marker of axonal degeneration, might provide diagnostic and prognostic information on the disease. All ALS patients were screened for SOD1 mutations. Ten of the familial and five of the sporadic cases carried SOD1 mutations. NF-L concentration [median (range)] was strongly elevated in ALS [2110 (255-10 800) ng/l] compared with reference patients and healthy controls [277 (<125-15 506) and 175 (<125-710) ng/l, respectively, P < 0.001] and correlated inversely with disease duration (Spearman R = -0.518, P = 0.001). NF-L levels were lower in SOD1 mutation-associated ALS compared with SOD1 wild-type (wt) ALS (P = 0.03). In conclusion, CSF NF-L levels may provide both diagnostic and prognostic information, particularly in SOD1 wt ALS.
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Affiliation(s)
- H Zetterberg
- Department of Neurochemistry and Psychiatry, Sahlgrenska University Hospital, Göteborg University, Göteborg, Sweden.
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