1
|
Suzuki N, Nishiyama A, Warita H, Aoki M. Genetics of amyotrophic lateral sclerosis: seeking therapeutic targets in the era of gene therapy. J Hum Genet 2023; 68:131-152. [PMID: 35691950 PMCID: PMC9968660 DOI: 10.1038/s10038-022-01055-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/17/2022] [Accepted: 05/29/2022] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is an intractable disease that causes respiratory failure leading to mortality. The main locus of ALS is motor neurons. The success of antisense oligonucleotide (ASO) therapy in spinal muscular atrophy (SMA), a motor neuron disease, has triggered a paradigm shift in developing ALS therapies. The causative genes of ALS and disease-modifying genes, including those of sporadic ALS, have been identified one after another. Thus, the freedom of target choice for gene therapy has expanded by ASO strategy, leading to new avenues for therapeutic development. Tofersen for superoxide dismutase 1 (SOD1) was a pioneer in developing ASO for ALS. Improving protocols and devising early interventions for the disease are vital. In this review, we updated the knowledge of causative genes in ALS. We summarized the genetic mutations identified in familial ALS and their clinical features, focusing on SOD1, fused in sarcoma (FUS), and transacting response DNA-binding protein. The frequency of the C9ORF72 mutation is low in Japan, unlike in Europe and the United States, while SOD1 and FUS are more common, indicating that the target mutations for gene therapy vary by ethnicity. A genome-wide association study has revealed disease-modifying genes, which could be the novel target of gene therapy. The current status and prospects of gene therapy development were discussed, including ethical issues. Furthermore, we discussed the potential of axonal pathology as new therapeutic targets of ALS from the perspective of early intervention, including intra-axonal transcription factors, neuromuscular junction disconnection, dysregulated local translation, abnormal protein degradation, mitochondrial pathology, impaired axonal transport, aberrant cytoskeleton, and axon branching. We simultaneously discuss important pathological states of cell bodies: persistent stress granules, disrupted nucleocytoplasmic transport, and cryptic splicing. The development of gene therapy based on the elucidation of disease-modifying genes and early intervention in molecular pathology is expected to become an important therapeutic strategy in ALS.
Collapse
Affiliation(s)
- Naoki Suzuki
- Department of Neurology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan.
| | - Ayumi Nishiyama
- Department of Neurology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan
| | - Hitoshi Warita
- Department of Neurology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan
| | - Masashi Aoki
- Department of Neurology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan.
| |
Collapse
|
2
|
Del Tredici K, Braak H. Neuropathology and neuroanatomy of TDP-43 amyotrophic lateral sclerosis. Curr Opin Neurol 2022; 35:660-671. [PMID: 36069419 DOI: 10.1097/wco.0000000000001098] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
PURPOSE OF REVIEW Intracellular inclusions consisting of the abnormal TDP-43 protein and its nucleocytoplasmic mislocalization in selected cell types are hallmark pathological features of sALS. Descriptive (histological, morphological), anatomical, and molecular studies all have improved our understanding of the neuropathology of sporadic amyotrophic lateral sclerosis (sALS). This review highlights some of the latest developments in the field. RECENT FINDINGS Increasing evidence exists from experimental models for the prion-like nature of abnormal TDP-43, including a strain-effect, and with the help of neuroimaging-based studies, for spreading of disease along corticofugal connectivities in sALS. Progress has also been made with respect to finding and establishing reliable biomarkers (neurofilament levels, diffusor tensor imaging). SUMMARY The latest findings may help to elucidate the preclinical phase of sALS and to define possible mechanisms for delaying or halting disease development and progression.
Collapse
Affiliation(s)
- Kelly Del Tredici
- Clinical Neuroanatomy Section, Department of Neurology, Center for Biomedical Research, University of Ulm, Ulm, Germany
| | | |
Collapse
|
3
|
Theunissen F, Anderton RS, Mastaglia FL, James I, Bedlack R, Akkari PA. Intronic NEFH variant is associated with reduced risk for sporadic ALS and later age of disease onset. Sci Rep 2022; 12:14739. [PMID: 36042248 PMCID: PMC9427846 DOI: 10.1038/s41598-022-18942-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 08/22/2022] [Indexed: 11/30/2022] Open
Abstract
Neurofilament heavy (NEFH) is one of the critical proteins required for the formation of the neuronal cytoskeleton and polymorphisms in NEFH are reported as a rare cause of sporadic ALS (sALS). In the current study, a candidate tetranucleotide (TTTA) repeat variant in NEFH was selected using an in-silico short structural variant (SSV) evaluation algorithm and investigated in two cohorts of North American sALS patients, both separately and combined (Duke cohort n = 138, Coriell cohort n = 333; combined cohort n = 471), compared to a group of healthy controls from the Coriell Institute biobank (n = 496). Stratification according to site of disease onset revealed that the 9 TTTA allele was associated with reduced disease risk, specifically confined to spinal-onset sALS patients in the Duke cohort (p = 0.001). Furthermore, carriage of the 10 TTTA allele was associated with a 2.7 year later age of disease onset in the larger combined sALS cohort (p = 0.02). These results suggest that the 9 and 10 TTTA motif length may have a protective advantage for potentially lowering the risk of sALS and delaying the age of disease onset, however, these results need to be replicated in larger multicenter and multi-ethnic cohorts.
Collapse
Affiliation(s)
- Frances Theunissen
- Perron Institute for Neurological and Translational Science, First floor, RR block, QEII Medical Centre, 8 Verdun St, Nedlands, WA, 6009, Australia.,Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
| | - Ryan S Anderton
- Perron Institute for Neurological and Translational Science, First floor, RR block, QEII Medical Centre, 8 Verdun St, Nedlands, WA, 6009, Australia.,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, WA, Australia.,School of Health Sciences and Institute for Health Research, University of Notre Dame Australia, Fremantle, WA, Australia
| | - Frank L Mastaglia
- Perron Institute for Neurological and Translational Science, First floor, RR block, QEII Medical Centre, 8 Verdun St, Nedlands, WA, 6009, Australia.,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, WA, Australia
| | - Ian James
- Institute for Immunology and Infectious Diseases, Murdoch University, Perth, WA, Australia
| | | | - P Anthony Akkari
- Perron Institute for Neurological and Translational Science, First floor, RR block, QEII Medical Centre, 8 Verdun St, Nedlands, WA, 6009, Australia. .,Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, WA, Australia. .,Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia. .,Department of Neurology, Duke University, Durham, NC, USA.
| |
Collapse
|
4
|
Laneve P, Tollis P, Caffarelli E. RNA Deregulation in Amyotrophic Lateral Sclerosis: The Noncoding Perspective. Int J Mol Sci 2021; 22:10285. [PMID: 34638636 PMCID: PMC8508793 DOI: 10.3390/ijms221910285] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/17/2021] [Accepted: 09/22/2021] [Indexed: 12/18/2022] Open
Abstract
RNA metabolism is central to cellular physiopathology. Almost all the molecular pathways underpinning biological processes are affected by the events governing the RNA life cycle, ranging from transcription to degradation. The deregulation of these processes contributes to the onset and progression of human diseases. In recent decades, considerable efforts have been devoted to the characterization of noncoding RNAs (ncRNAs) and to the study of their role in the homeostasis of the nervous system (NS), where they are highly enriched. Acting as major regulators of gene expression, ncRNAs orchestrate all the steps of the differentiation programs, participate in the mechanisms underlying neural functions, and are crucially implicated in the development of neuronal pathologies, among which are neurodegenerative diseases. This review aims to explore the link between ncRNA dysregulation and amyotrophic lateral sclerosis (ALS), the most frequent motoneuron (MN) disorder in adults. Notably, defective RNA metabolism is known to be largely associated with this pathology, which is often regarded as an RNA disease. We also discuss the potential role that these transcripts may play as diagnostic biomarkers and therapeutic targets.
Collapse
Affiliation(s)
- Pietro Laneve
- Institute of Molecular Biology and Pathology, National Research Council, 00185 Rome, Italy
| | - Paolo Tollis
- Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, 00185 Rome, Italy;
| | - Elisa Caffarelli
- Institute of Molecular Biology and Pathology, National Research Council, 00185 Rome, Italy
| |
Collapse
|
5
|
Lin F, Lin W, Zhu C, Lin J, Zhu J, Li XY, Wang Z, Wang C, Huang H. Sequencing of neurofilament genes identified NEFH Ser787Arg as a novel risk variant of sporadic amyotrophic lateral sclerosis in Chinese subjects. BMC Med Genomics 2021; 14:222. [PMID: 34511133 PMCID: PMC8436554 DOI: 10.1186/s12920-021-01073-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 09/01/2021] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease with neuronal cell inclusions composed of neurofilaments and other abnormal aggregative proteins as pathological hallmarks. Approximately 90% of patients have sporadic cases (sALS), and at least 4 genes, i.e. C9orf72, SOD1, FUS and TARDBP, have been identified as the main causative genes, while many others have been proposed as potential risk genes. However, these mutations could explain only ~ 10% of sALS cases. The neurofilament polypeptides encoded by NEFH, NEFM, and NEFL are promising protein biomarkers for ALS and other degenerative diseases. However, whether the genetic variants of these genes were associated with ALS remain ambiguous. METHODS Here, we used PCR-Sanger to sequence the exons of these three genes in a cohort of 371 sALS patients and 711 healthy controls (Phase I) and validated the risk variant in another 300 sALS patients and 1076 controls (Phase II). RESULTS A total of 92 variants were identified, including 36 rare heterozygous variants in NEFH, 27 in NEFM, and 16 in NEFL, and only rs568759161 (p.Ser787Arg) in NEFH reached nominal statistical power (P = 0.02 at Phase I, P = 0.009 at Phase II) in the case-control comparison. Together, the Phase I and II studies showed the significantly higher frequency of the variant in cases (9/1342, 0.67%) than in controls (2/3574, 0.07%) (OR 12.06; 95% CI 2.60-55.88; P = 0.0003). No variants passed multiple testing in the discovery cohort, but rs568759161 was associated with ALS in a replication cohort. CONCLUSIONS Our results confirmed that NEFH Ser787Arg is a novel sALS risk variant in Chinese subjects, but NEFM and NEFL were not associated with sALS. These data may have implications for genetic counselling and for understanding the pathogenesis of sALS.
Collapse
Affiliation(s)
- Feng Lin
- Department of Neurology, Fujian Medical University Union Hospital, Fujian, 350001, China
| | - Wanhui Lin
- Department of Neurology, Fujian Medical University Union Hospital, Fujian, 350001, China
| | - Chaofeng Zhu
- Department of Neurology, Fujian Medical University Union Hospital, Fujian, 350001, China
| | - Jilan Lin
- Department of Neurology, Fujian Medical University Union Hospital, Fujian, 350001, China
| | - Junge Zhu
- Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, 100053, China
| | - Xu-Ying Li
- Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, 100053, China
| | - Zhanjun Wang
- Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, 100053, China
| | - Chaodong Wang
- Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, 100053, China
| | - Huapin Huang
- Department of Neurology, Fujian Medical University Union Hospital, Fujian, 350001, China.
| |
Collapse
|
6
|
Storage of Mutant Human SOD1 in Non-Neural Cells from the Type-1 Amyotrophic Lateral Sclerosis rat G93A Model Correlated with the Lysosomes' Dysfunction. Biomedicines 2021; 9:biomedicines9091080. [PMID: 34572266 PMCID: PMC8470315 DOI: 10.3390/biomedicines9091080] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/20/2021] [Accepted: 08/21/2021] [Indexed: 02/07/2023] Open
Abstract
Herein, we explored the impact of the lysosome dysfunction during the progression of Amyotrophic Lateral Sclerosis type-1 (ALS1). We conducted the study in non-neural cells, primary fibroblasts (rFFFs), and bone marrow-mesenchymal stem cells (rBM-MSCs), isolated from the animal model ratG93A for ALS1 at two stages of the disease: Pre-symptomatic-stage (ALS1-PreS) and Terminal-stage (ALS1-EndS). We documented the storage of human mutant Superoxide Dismutase 1, SOD1G93A (SOD1*) in the lysosomes of ALS1-rFFFs and ALS1-rBM-MSCs and demonstrated the hallmarks of the disease in non-neural cells as in ratG93A-ALS1-tissues. We showed that the SOD1* storage is associated with the altered glycohydrolases and proteases levels in tissues and both cell types from ALS1-PreS to ALS1-EndS. Only in ALS1-rFFFs, the lysosomes lost homeostasis, enlarge drastically, and contribute to the cell metabolic damage. Contrariwise, in ALS1-rBM-MSCs, we found a negligible metabolic dysfunction, which makes these cells’ status similar to WT. We addressed this phenomenon to a safety mechanism perhaps associated with an enhanced lysosomal autophagic activity in ALS1-rBM-MSCs compared to ALS1-rFFFs, in which the lysosomal level of LC3-II/LC3I was comparable to that of WT-rFFFs. We suggested that the autophagic machinery could balance the storage of SOD1* aggregates and the lysosomal enzyme dysfunction even in ALS1-EndS-stem cells.
Collapse
|
7
|
Castellanos-Montiel MJ, Chaineau M, Durcan TM. The Neglected Genes of ALS: Cytoskeletal Dynamics Impact Synaptic Degeneration in ALS. Front Cell Neurosci 2020; 14:594975. [PMID: 33281562 PMCID: PMC7691654 DOI: 10.3389/fncel.2020.594975] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/21/2020] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that selectively affects motor neurons (MNs) of the cortex, brainstem, and spinal cord. Several genes have been linked to both familial (fALS) and sporadic (sALS) cases of ALS. Among all the ALS-related genes, a group of genes known to directly affect cytoskeletal dynamics (ALS2, DCTN1, PFN1, KIF5A, NF-L, NF-H, PRPH, SPAST, and TUBA4A) is of high importance for MN health and survival, considering that MNs are large polarized cells with axons that can reach up to 1 m in length. In particular, cytoskeletal dynamics facilitate the transport of organelles and molecules across the long axonal distances within the cell, playing a key role in synapse maintenance. The majority of ALS-related genes affecting cytoskeletal dynamics were identified within the past two decades, making it a new area to explore for ALS. The purpose of this review is to provide insights into ALS-associated cytoskeletal genes and outline how recent studies have pointed towards novel pathways that might be impacted in ALS. Further studies making use of extensive analysis models to look for true hits, the newest technologies such as CRIPSR/Cas9, human induced pluripotent stem cells (iPSCs) and axon sequencing, as well as the development of more transgenic animal models could potentially help to: differentiate the variants that truly act as a primary cause of the disease from the ones that act as risk factors or disease modifiers, identify potential interactions between two or more ALS-related genes in disease onset and progression and increase our understanding of the molecular mechanisms leading to cytoskeletal defects. Altogether, this information will give us a hint on the real contribution of the cytoskeletal ALS-related genes during this lethal disease.
Collapse
Affiliation(s)
| | - Mathilde Chaineau
- Early Drug Discovery Unit (EDDU), Montreal Neurological Institute-Hospital, McGill University, Montreal, QC, Canada
| | - Thomas M Durcan
- Early Drug Discovery Unit (EDDU), Montreal Neurological Institute-Hospital, McGill University, Montreal, QC, Canada
| |
Collapse
|
8
|
Briese M, Saal-Bauernschubert L, Lüningschrör P, Moradi M, Dombert B, Surrey V, Appenzeller S, Deng C, Jablonka S, Sendtner M. Loss of Tdp-43 disrupts the axonal transcriptome of motoneurons accompanied by impaired axonal translation and mitochondria function. Acta Neuropathol Commun 2020; 8:116. [PMID: 32709255 PMCID: PMC7379803 DOI: 10.1186/s40478-020-00987-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 07/04/2020] [Indexed: 01/02/2023] Open
Abstract
Protein inclusions containing the RNA-binding protein TDP-43 are a pathological hallmark of amyotrophic lateral sclerosis and other neurodegenerative disorders. The loss of TDP-43 function that is associated with these inclusions affects post-transcriptional processing of RNAs in multiple ways including pre-mRNA splicing, nucleocytoplasmic transport, modulation of mRNA stability and translation. In contrast, less is known about the role of TDP-43 in axonal RNA metabolism in motoneurons. Here we show that depletion of Tdp-43 in primary motoneurons affects axon growth. This defect is accompanied by subcellular transcriptome alterations in the axonal and somatodendritic compartment. The axonal localization of transcripts encoding components of the cytoskeleton, the translational machinery and transcripts involved in mitochondrial energy metabolism were particularly affected by loss of Tdp-43. Accordingly, we observed reduced protein synthesis and disturbed mitochondrial functions in axons of Tdp-43-depleted motoneurons. Treatment with nicotinamide rescued the axon growth defect associated with loss of Tdp-43. These results show that Tdp-43 depletion in motoneurons affects several pathways integral to axon health indicating that loss of TDP-43 function could thus make a major contribution to axonal pathomechanisms in ALS.
Collapse
|
9
|
Suzuki N, Akiyama T, Warita H, Aoki M. Omics Approach to Axonal Dysfunction of Motor Neurons in Amyotrophic Lateral Sclerosis (ALS). Front Neurosci 2020; 14:194. [PMID: 32269505 PMCID: PMC7109447 DOI: 10.3389/fnins.2020.00194] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 02/24/2020] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is an intractable adult-onset neurodegenerative disease that leads to the loss of upper and lower motor neurons (MNs). The long axons of MNs become damaged during the early stages of ALS. Genetic and pathological analyses of ALS patients have revealed dysfunction in the MN axon homeostasis. However, the molecular pathomechanism for the degeneration of axons in ALS has not been fully elucidated. This review provides an overview of the proposed axonal pathomechanisms in ALS, including those involving the neuronal cytoskeleton, cargo transport within axons, axonal energy supply, clearance of junk protein, neuromuscular junctions (NMJs), and aberrant axonal branching. To improve understanding of the global changes in axons, the review summarizes omics analyses of the axonal compartments of neurons in vitro and in vivo, including a motor nerve organoid approach that utilizes microfluidic devices developed by this research group. The review also discusses the relevance of intra-axonal transcription factors frequently identified in these omics analyses. Local axonal translation and the relationship among these pathomechanisms should be pursued further. The development of novel strategies to analyze axon fractions provides a new approach to establishing a detailed understanding of resilience of long MN and MN pathology in ALS.
Collapse
Affiliation(s)
- Naoki Suzuki
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan.,Department of Neurology, Shodo-kai Southern Tohoku General Hospital, Miyagi, Japan
| | - Tetsuya Akiyama
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
| | - Hitoshi Warita
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
| | - Masashi Aoki
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
| |
Collapse
|
10
|
Bennett SA, Tanaz R, Cobos SN, Torrente MP. Epigenetics in amyotrophic lateral sclerosis: a role for histone post-translational modifications in neurodegenerative disease. Transl Res 2019; 204:19-30. [PMID: 30391475 PMCID: PMC6331271 DOI: 10.1016/j.trsl.2018.10.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 09/26/2018] [Accepted: 10/09/2018] [Indexed: 02/06/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is the third most common adult onset neurodegenerative disorder worldwide. It is generally characterized by progressive paralysis starting at the limbs ultimately leading to death caused by respiratory failure. There is no cure and current treatments fail to slow the progression of the disease. As such, new treatment options are desperately needed. Epigenetic targets are an attractive possibility because they are reversible. Epigenetics refers to heritable changes in gene expression unrelated to changes in DNA sequence. Three main epigenetic mechanisms include the methylation of DNA, microRNAs and the post-translational modification of histone proteins. Histone modifications occur in many amino acid residues and include phosphorylation, acetylation, methylation as well as other chemical moieties. Recent evidence points to a possible role for epigenetic mechanisms in the etiology of ALS. Here, we review recent advances linking ALS and epigenetics, with a strong focus on histone modifications. Both local and global changes in histone modification profiles are associated with ALS drawing attention to potential targets for future diagnostic and treatment approaches.
Collapse
Affiliation(s)
- Seth A Bennett
- Department of Chemistry, Brooklyn College, Brooklyn, NewYork; Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, New York
| | - Royena Tanaz
- Department of Chemistry, Brooklyn College, Brooklyn, NewYork
| | - Samantha N Cobos
- Department of Chemistry, Brooklyn College, Brooklyn, NewYork; Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, NY 10016
| | - Mariana P Torrente
- Department of Chemistry, Brooklyn College, Brooklyn, NewYork; Ph.D. Programs in Chemistry, Biochemistry, and Biology, The Graduate Center of the City University of New York, New York, New York.
| |
Collapse
|
11
|
Riancho J, Gonzalo I, Ruiz-Soto M, Berciano J. Why do motor neurons degenerate? Actualisation in the pathogenesis of amyotrophic lateral sclerosis. NEUROLOGÍA (ENGLISH EDITION) 2019. [DOI: 10.1016/j.nrleng.2015.12.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
12
|
Riancho J, Gonzalo I, Ruiz-Soto M, Berciano J. ¿Por qué degeneran las motoneuronas? Actualización en la patogenia de la esclerosis lateral amiotrófica. Neurologia 2019; 34:27-37. [DOI: 10.1016/j.nrl.2015.12.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 12/06/2015] [Indexed: 12/11/2022] Open
|
13
|
Wang S, Ji D, Yang Q, Li M, Ma Z, Zhang S, Li H. NEFLb impairs early nervous system development via regulation of neuron apoptosis in zebrafish. J Cell Physiol 2018; 234:11208-11218. [PMID: 30569449 DOI: 10.1002/jcp.27771] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 10/30/2018] [Indexed: 02/06/2023]
Abstract
Neurofilament light chain (NEFL), a subunit of neurofilament, has been shown to play an important role in pathogenic neurodegenerative disease and in radial axonal growth. However, information remains largely lacking regarding the function of NEFL in early development to date. In this study, we demonstrated the presence of two nefl genes, nefla and neflb, in zebrafish, generated by fish-specific third round genome duplication. These duplicated nefl genes were predominantly expressed in the nervous system with an overlapping and distinct expression pattern. Both gene knockdown and rescue experiments show that it was neflb rather than nefla that played an indispensable role in nervous system development. It was also found that neflb knockdown resulted in striking apoptosis of the neurons in the brain and spinal cord, leading to morphological defects such as brain structure disorder and trunk bending. Thus, we report a previously uncharacterized role of NEFL that NEFLb impairs the early development of zebrafish nervous system via regulation of the neuron apoptosis in the brain and spinal cord.
Collapse
Affiliation(s)
- Su Wang
- Laboratory for Evolution & Development, Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Evolution & Development, Department of Marine Biology, Ocean University of China, Qingdao, China
| | - Dongrui Ji
- Laboratory for Evolution & Development, Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Evolution & Development, Department of Marine Biology, Ocean University of China, Qingdao, China
| | - Qingyun Yang
- Laboratory for Evolution & Development, Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Evolution & Development, Department of Marine Biology, Ocean University of China, Qingdao, China
| | - Mingyue Li
- Laboratory for Evolution & Development, Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Evolution & Development, Department of Marine Biology, Ocean University of China, Qingdao, China
| | - Zengyu Ma
- Laboratory for Evolution & Development, Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Evolution & Development, Department of Marine Biology, Ocean University of China, Qingdao, China
| | - Shicui Zhang
- Laboratory for Evolution & Development, Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Evolution & Development, Department of Marine Biology, Ocean University of China, Qingdao, China
| | - Hongyan Li
- Laboratory for Evolution & Development, Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Evolution & Development, Department of Marine Biology, Ocean University of China, Qingdao, China
| |
Collapse
|
14
|
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.
Collapse
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.
| |
Collapse
|
15
|
Oberstadt M, Claßen J, Arendt T, Holzer M. TDP-43 and Cytoskeletal Proteins in ALS. Mol Neurobiol 2017; 55:3143-3151. [PMID: 28466273 DOI: 10.1007/s12035-017-0543-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 04/07/2017] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) represents a rapidly progressing neurodegenerative disease and is characterized by a degeneration of motor neurons. Motor neurons are particularly susceptible to selective and early degeneration because of their extended axon length and their dependency on the cytoskeleton for its stability, signaling, and axonal transport. The motor neuron cytoskeleton comprises actin filaments, neurofilaments like peripherin, and microtubules. The Transactivating Response Region (TAR) DNA Binding Protein (TDP-43) forms characteristic cytoplasmic aggregates in motor neurons of ALS patients, and at least in part, the pathogenesis of ALS seems to be driven by toxic pTDP-43 aggregates in cytoplasm, which lead to a diminished axon formation and reduced axon length. Diminished axon formation and reduced axon length suggest an interaction of TDP-43 with the cytoskeleton of motor neurons. TDP-43 interacts with several cytoskeletal components, e.g., the microtubule-associated protein 1B (MAP1B) or the neurofilament light chain (NFL) through direct binding to its RNA. From a clinical perspective, cytoskeletal biomarkers like phosphorylated neurofilament heavy chain (pNFH) and NFL are already clinically used in ALS patients to predict survival, disease progression, and duration. Thus, in this review, we focus on the interaction of TDP-43 with the different cytoskeleton components such as actin filaments, neurofilaments, and microtubules as well as their associated proteins as one aspect in the complex pathogenesis of ALS.
Collapse
Affiliation(s)
- Moritz Oberstadt
- Department of Neurology, University of Leipzig, Liebigstraße 20, 04103, Leipzig, Germany.
| | - Joseph Claßen
- Department of Neurology, University of Leipzig, Liebigstraße 20, 04103, Leipzig, Germany
| | - Thomas Arendt
- Department for Molecular and Cellular Mechanisms of Neurodegeneration, Paul Flechsig Institute for Brain Research, University of Leipzig, Liebigstraße 19, 04103, Leipzig, Germany
| | - Max Holzer
- Department for Molecular and Cellular Mechanisms of Neurodegeneration, Paul Flechsig Institute for Brain Research, University of Leipzig, Liebigstraße 19, 04103, Leipzig, Germany
| |
Collapse
|
16
|
Genome-wide RNA-seq of iPSC-derived motor neurons indicates selective cytoskeletal perturbation in Brown-Vialetto disease that is partially rescued by riboflavin. Sci Rep 2017; 7:46271. [PMID: 28382968 PMCID: PMC5382781 DOI: 10.1038/srep46271] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 03/14/2017] [Indexed: 12/14/2022] Open
Abstract
Riboflavin is essential in numerous cellular oxidation/reduction reactions but is not synthesized by mammalian cells. Riboflavin absorption occurs through the human riboflavin transporters RFVT1 and RFVT3 in the intestine and RFVT2 in the brain. Mutations in these genes are causative for the Brown–Vialetto–Van Laere (BVVL), childhood-onset syndrome characterized by a variety of cranial nerve palsies as well as by spinal cord motor neuron (MN) degeneration. Why mutations in RFVTs result in a neural cell–selective disorder is unclear. As a novel tool to gain insights into the pathomechanisms underlying the disease, we generated MNs from induced pluripotent stem cells (iPSCs) derived from BVVL patients as an in vitro disease model. BVVL-MNs explained a reduction in axon elongation, partially improved by riboflavin supplementation. RNA sequencing profiles and protein studies of the cytoskeletal structures showed a perturbation in the neurofilament composition in BVVL-MNs. Furthermore, exploring the autophagy–lysosome pathway, we observed a reduced autophagic/mitophagic flux in patient MNs. These features represent emerging pathogenetic mechanisms in BVVL-associated neurodegeneration, partially rescued by riboflavin supplementation. Our data showed that this therapeutic strategy could have some limits in rescuing all of the disease features, suggesting the need to develop complementary novel therapeutic strategies.
Collapse
|
17
|
Toedebusch CM, Bachrach MD, Garcia VB, Johnson GC, Katz ML, Shaw G, Coates JR, Garcia ML. Cerebrospinal Fluid Levels of Phosphorylated Neurofilament Heavy as a Diagnostic Marker of Canine Degenerative Myelopathy. J Vet Intern Med 2017; 31:513-520. [PMID: 28186658 PMCID: PMC5354061 DOI: 10.1111/jvim.14659] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 12/05/2016] [Accepted: 12/22/2016] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND No definitive, antemortem diagnostic test for canine degenerative myelopathy (DM) is available. Phosphorylated neurofilament heavy (pNF-H) is a promising biomarker for nervous system diseases. HYPOTHESIS/OBJECTIVE Cerebrospinal fluid (CSF) and serum pNF-H is a detectable biological marker for diagnosis of canine DM. ANIMALS Fifty-three DM-affected, 27 neurologically normal, 7 asymptomatic at-risk, and 12 DM mimic dogs. METHODS Archived CSF and serum pNF-H concentrations were determined by a commercially available ELISA. A receiver-operating characteristic (ROC) curve was generated with CSF values. RESULTS Compared with old control dogs, median CSF pNF-H concentration was increased in all stages of DM; old dogs 5.1 ng/mL (interquartile range [IQR] 1.4-9.3) versus DM stage 1 23.9 ng/mL (IQR 20.8-29.6; P < .05) versus DM stage 2 36.8 ng/mL (IQR 22.9-51.2; P < .0001) versus DM stage 3 25.2 ng/mL (IQR 20.2-61.8; P < .001) versus DM stage 4 38.0 ng/mL (IQR 11.6-59.9; P < .01). Degenerative myelopathy stage 1 dogs had increased median CSF pNF-H concentrations compared with asymptomatic, at-risk dogs (3.4 ng/mL [IQR 1.5-10.9; P < .01]) and DM mimics (6.6 ng/mL [IQR 3.0-12.3; P < .01]). CSF pNF-H concentration >20.25 ng/mL was 80.4% sensitive (confidence interval [CI] 66.09-90.64%) and 93.6% specific (CI 78.58-99.21%) for DM. Area under the ROC curve was 0.9467 (CI 0.92-0.9974). No differences in serum pNF-H concentration were found between control and DM-affected dogs. CONCLUSIONS AND CLINICAL IMPORTANCE pNF-H concentration in CSF is a sensitive biomarker for diagnosis of DM. Although there was high specificity for DM in this cohort, further study should focus on a larger cohort of DM mimics, particularly other central and peripheral axonopathies.
Collapse
Affiliation(s)
- C M Toedebusch
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri-Columbia, Columbia, MO
| | - M D Bachrach
- Division of Biological Sciences, Bond Life Sciences Center, University of Missouri-Columbia, Columbia, MO
| | - V B Garcia
- Division of Biological Sciences, Bond Life Sciences Center, University of Missouri-Columbia, Columbia, MO
| | - G C Johnson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri-Columbia, Columbia, MO
| | - M L Katz
- Mason Eye Institute, School of Medicine, University of Missouri-Columbia, Columbia, MO
| | - G Shaw
- EnCor Biotechnology Inc, Gainesville, FL
| | - J R Coates
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri-Columbia, Columbia, MO
| | - M L Garcia
- Division of Biological Sciences, Bond Life Sciences Center, University of Missouri-Columbia, Columbia, MO
| |
Collapse
|
18
|
Mutant PFN1 causes ALS phenotypes and progressive motor neuron degeneration in mice by a gain of toxicity. Proc Natl Acad Sci U S A 2016; 113:E6209-E6218. [PMID: 27681617 DOI: 10.1073/pnas.1605964113] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Mutations in the profilin 1 (PFN1) gene cause amyotrophic lateral sclerosis (ALS), a neurodegenerative disease caused by the loss of motor neurons leading to paralysis and eventually death. PFN1 is a small actin-binding protein that promotes formin-based actin polymerization and regulates numerous cellular functions, but how the mutations in PFN1 cause ALS is unclear. To investigate this problem, we have generated transgenic mice expressing either the ALS-associated mutant (C71G) or wild-type protein. Here, we report that mice expressing the mutant, but not the wild-type, protein had relentless progression of motor neuron loss with concomitant progressive muscle weakness ending in paralysis and death. Furthermore, mutant, but not wild-type, PFN1 forms insoluble aggregates, disrupts cytoskeletal structure, and elevates ubiquitin and p62/SQSTM levels in motor neurons. Unexpectedly, the acceleration of motor neuron degeneration precedes the accumulation of mutant PFN1 aggregates. These results suggest that although mutant PFN1 aggregation may contribute to neurodegeneration, it does not trigger its onset. Importantly, these experiments establish a progressive disease model that can contribute toward identifying the mechanisms of ALS pathogenesis and the development of therapeutic treatments.
Collapse
|
19
|
Neurofilament depletion improves microtubule dynamics via modulation of Stat3/stathmin signaling. Acta Neuropathol 2016; 132:93-110. [PMID: 27021905 PMCID: PMC4911381 DOI: 10.1007/s00401-016-1564-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 03/14/2016] [Accepted: 03/15/2016] [Indexed: 12/31/2022]
Abstract
In neurons, microtubules form a dense array within axons, and the stability and function of this microtubule network is modulated by neurofilaments. Accumulation of neurofilaments has been observed in several forms of neurodegenerative diseases, but the mechanisms how elevated neurofilament levels destabilize axons are unknown so far. Here, we show that increased neurofilament expression in motor nerves of pmn mutant mice, a model of motoneuron disease, causes disturbed microtubule dynamics. The disease is caused by a point mutation in the tubulin-specific chaperone E (Tbce) gene, leading to an exchange of the most C-terminal amino acid tryptophan to glycine. As a consequence, the TBCE protein becomes instable which then results in destabilization of axonal microtubules and defects in axonal transport, in particular in motoneurons. Depletion of neurofilament increases the number and regrowth of microtubules in pmn mutant motoneurons and restores axon elongation. This effect is mediated by interaction of neurofilament with the stathmin complex. Accumulating neurofilaments associate with stathmin in axons of pmn mutant motoneurons. Depletion of neurofilament by Nefl knockout increases Stat3–stathmin interaction and stabilizes the microtubules in pmn mutant motoneurons. Consequently, counteracting enhanced neurofilament expression improves axonal maintenance and prolongs survival of pmn mutant mice. We propose that this mechanism could also be relevant for other neurodegenerative diseases in which neurofilament accumulation and loss of microtubules are prominent features.
Collapse
|
20
|
Scekic-Zahirovic J, Sendscheid O, El Oussini H, Jambeau M, Sun Y, Mersmann S, Wagner M, Dieterlé S, Sinniger J, Dirrig-Grosch S, Drenner K, Birling MC, Qiu J, Zhou Y, Li H, Fu XD, Rouaux C, Shelkovnikova T, Witting A, Ludolph AC, Kiefer F, Storkebaum E, Lagier-Tourenne C, Dupuis L. Toxic gain of function from mutant FUS protein is crucial to trigger cell autonomous motor neuron loss. EMBO J 2016; 35:1077-97. [PMID: 26951610 PMCID: PMC4868956 DOI: 10.15252/embj.201592559] [Citation(s) in RCA: 171] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 01/28/2016] [Accepted: 02/01/2016] [Indexed: 12/12/2022] Open
Abstract
FUS is an RNA-binding protein involved in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Cytoplasmic FUS-containing aggregates are often associated with concomitant loss of nuclear FUS Whether loss of nuclear FUS function, gain of a cytoplasmic function, or a combination of both lead to neurodegeneration remains elusive. To address this question, we generated knockin mice expressing mislocalized cytoplasmic FUS and complete FUS knockout mice. Both mouse models display similar perinatal lethality with respiratory insufficiency, reduced body weight and length, and largely similar alterations in gene expression and mRNA splicing patterns, indicating that mislocalized FUS results in loss of its normal function. However, FUS knockin mice, but not FUS knockout mice, display reduced motor neuron numbers at birth, associated with enhanced motor neuron apoptosis, which can be rescued by cell-specific CRE-mediated expression of wild-type FUS within motor neurons. Together, our findings indicate that cytoplasmic FUS mislocalization not only leads to nuclear loss of function, but also triggers motor neuron death through a toxic gain of function within motor neurons.
Collapse
Affiliation(s)
- Jelena Scekic-Zahirovic
- Faculté de Médecine, INSERM U1118, Strasbourg, France Université de Strasbourg UMR_S1118, Strasbourg, France
| | - Oliver Sendscheid
- Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Muenster, Germany Faculty of Medicine, University of Muenster, Muenster, Germany
| | - Hajer El Oussini
- Faculté de Médecine, INSERM U1118, Strasbourg, France Université de Strasbourg UMR_S1118, Strasbourg, France
| | - Mélanie Jambeau
- Department of Neurosciences, University of California, San Diego La Jolla, CA, USA Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA, USA
| | - Ying Sun
- Department of Neurosciences, University of California, San Diego La Jolla, CA, USA Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA, USA
| | - Sina Mersmann
- Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Muenster, Germany Faculty of Medicine, University of Muenster, Muenster, Germany
| | - Marina Wagner
- Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Muenster, Germany Faculty of Medicine, University of Muenster, Muenster, Germany
| | - Stéphane Dieterlé
- Faculté de Médecine, INSERM U1118, Strasbourg, France Université de Strasbourg UMR_S1118, Strasbourg, France
| | - Jérome Sinniger
- Faculté de Médecine, INSERM U1118, Strasbourg, France Université de Strasbourg UMR_S1118, Strasbourg, France
| | - Sylvie Dirrig-Grosch
- Faculté de Médecine, INSERM U1118, Strasbourg, France Université de Strasbourg UMR_S1118, Strasbourg, France
| | - Kevin Drenner
- Department of Neurosciences, University of California, San Diego La Jolla, CA, USA Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA, USA
| | | | - Jinsong Qiu
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Yu Zhou
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Hairi Li
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Xiang-Dong Fu
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Caroline Rouaux
- Faculté de Médecine, INSERM U1118, Strasbourg, France Université de Strasbourg UMR_S1118, Strasbourg, France
| | | | - Anke Witting
- Department of Neurology University of Ulm, Ulm, Germany
| | | | - Friedemann Kiefer
- Mammalian Cell Signaling Laboratory, Department of Vascular Cell Biology, Max Planck Institute for Molecular Biomedicine, Muenster, Germany
| | - Erik Storkebaum
- Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Muenster, Germany Faculty of Medicine, University of Muenster, Muenster, Germany
| | - Clotilde Lagier-Tourenne
- Department of Neurosciences, University of California, San Diego La Jolla, CA, USA Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA, USA
| | - Luc Dupuis
- Faculté de Médecine, INSERM U1118, Strasbourg, France Université de Strasbourg UMR_S1118, Strasbourg, France
| |
Collapse
|
21
|
Role of Intermediate Filaments in Vesicular Traffic. Cells 2016; 5:cells5020020. [PMID: 27120621 PMCID: PMC4931669 DOI: 10.3390/cells5020020] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 04/13/2016] [Accepted: 04/20/2016] [Indexed: 12/28/2022] Open
Abstract
Intermediate filaments are an important component of the cellular cytoskeleton. The first established role attributed to intermediate filaments was the mechanical support to cells. However, it is now clear that intermediate filaments have many different roles affecting a variety of other biological functions, such as the organization of microtubules and microfilaments, the regulation of nuclear structure and activity, the control of cell cycle and the regulation of signal transduction pathways. Furthermore, a number of intermediate filament proteins have been involved in the acquisition of tumorigenic properties. Over the last years, a strong involvement of intermediate filament proteins in the regulation of several aspects of intracellular trafficking has strongly emerged. Here, we review the functions of intermediate filaments proteins focusing mainly on the recent knowledge gained from the discovery that intermediate filaments associate with key proteins of the vesicular membrane transport machinery. In particular, we analyze the current understanding of the contribution of intermediate filaments to the endocytic pathway.
Collapse
|
22
|
Zhao J, Liem RKH. α-Internexin and Peripherin: Expression, Assembly, Functions, and Roles in Disease. Methods Enzymol 2015; 568:477-507. [PMID: 26795481 DOI: 10.1016/bs.mie.2015.09.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
α-Internexin and peripherin are neuronal-specific intermediate filament (IF) proteins. α-Internexin is a type IV IF protein like the neurofilament triplet proteins (NFTPs, which include neurofilament light chain, neurofilament medium chain, and neurofilament high chain) that are generally considered to be the primary components of the neuronal IFs. However, α-internexin is often expressed together with the NFTPs and has been proposed as the fourth subunit of the neurofilaments in the central nervous system. α-Internexin is also expressed earlier in the development than the NFTPs and is a maker for neuronal IF inclusion disease. α-Internexin can self-polymerize in vitro and in transfected cells and it is present in the absence of the NFTP in development and in granule cells in the cerebellum. In contrast, peripherin is a type III IF protein. Like α-internexin, peripherin is specific to the nervous system, but it is expressed predominantly in the peripheral nervous system (PNS). Peripherin can also self-assemble both in vitro and in transfected cells. It is as abundant as the NFTPs in the sciatic nerve and can be considered a fourth subunit of the neurofilaments in the PNS. Peripherin has multiple isoforms that arise from intron retention, cryptic intron receptor site or alternative translation initiation. The functional significance of these isoforms is not clear. Peripherin is a major component found in inclusions of patients with amyotrophic lateral sclerosis (ALS) and peripherin expression is upregulated in ALS patients.
Collapse
Affiliation(s)
- Jian Zhao
- Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University College of Physicians and Surgeons, New York, USA
| | - Ronald K H Liem
- Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University College of Physicians and Surgeons, New York, USA.
| |
Collapse
|
23
|
Cloutier F, Marrero A, O'Connell C, Morin P. MicroRNAs as potential circulating biomarkers for amyotrophic lateral sclerosis. J Mol Neurosci 2014; 56:102-12. [PMID: 25433762 DOI: 10.1007/s12031-014-0471-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 11/17/2014] [Indexed: 01/04/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a condition primarily characterized by the selective loss of upper and lower motor neurons. Motor neuron loss gives rise to muscle tissue malfunctions, including weakness, spasticity, atrophy, and ultimately paralysis, with death typically due to respiratory failure within 2 to 5 years of symptoms' onset. The mean delay in time from presentation to diagnosis remains at over 1 year. Biomarkers are urgently needed to facilitate ALS diagnosis and prognosis as well as to act as indicators of therapeutic response in clinical trials. MicroRNAs (miRNAs) are small molecules that can influence posttranscriptional gene expression of a variety of transcript targets. Interestingly, miRNAs can be released into the circulation by pathologically affected tissues. This review presents therapeutic and diagnostic challenges associated with ALS, highlights the potential role of miRNAs in ALS, and discusses the diagnostic potential of these molecules in identifying ALS-specific miRNAs or in distinguishing between the various genotypic and phenotypic forms of ALS.
Collapse
Affiliation(s)
- Frank Cloutier
- Institut de l'Atlantique en Neurosciences Atlantic Institute, Vitalité Health Network, Centre Hospitalier Universitaire Dr Georges-L.-Dumont/Dr. Georges-L.-Dumont University Hospital Centre, Moncton, NB, Canada,
| | | | | | | |
Collapse
|
24
|
Tibshirani M, Tradewell ML, Mattina KR, Minotti S, Yang W, Zhou H, Strong MJ, Hayward LJ, Durham HD. Cytoplasmic sequestration of FUS/TLS associated with ALS alters histone marks through loss of nuclear protein arginine methyltransferase 1. Hum Mol Genet 2014; 24:773-86. [PMID: 25274782 DOI: 10.1093/hmg/ddu494] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mutations in the RNA-binding protein FUS/TLS (FUS) have been linked to the neurodegenerative disease amyotrophic lateral sclerosis (ALS). Although predominantly nuclear, this heterogenous nuclear ribonuclear protein (hnRNP) has multiple functions in RNA processing including intracellular trafficking. In ALS, mutant or wild-type (WT) FUS can form neuronal cytoplasmic inclusions. Asymmetric arginine methylation of FUS by the class 1 arginine methyltransferase, protein arginine methyltransferase 1 (PRMT1), regulates nucleocytoplasmic shuttling of FUS. In motor neurons of primary spinal cord cultures, redistribution of endogenous mouse and that of ectopically expressed WT or mutant human FUS to the cytoplasm led to nuclear depletion of PRMT1, abrogating methylation of its nuclear substrates. Specifically, hypomethylation of arginine 3 of histone 4 resulted in decreased acetylation of lysine 9/14 of histone 3 and transcriptional repression. Distribution of neuronal PRMT1 coincident with FUS also was detected in vivo in the spinal cord of FUS(R495X) transgenic mice. However, nuclear PRMT1 was not stable postmortem obviating meaningful evaluation of ALS autopsy cases. This study provides evidence for loss of PRMT1 function as a consequence of cytoplasmic accumulation of FUS in the pathogenesis of ALS, including changes in the histone code regulating gene transcription.
Collapse
Affiliation(s)
- Michael Tibshirani
- Montreal Neurological Institute and Department of Neurology/Neurosurgery, McGill University, Montreal, Quebec, Canada H3A 2B4
| | - Miranda L Tradewell
- Montreal Neurological Institute and Department of Neurology/Neurosurgery, McGill University, Montreal, Quebec, Canada H3A 2B4
| | - Katie R Mattina
- Montreal Neurological Institute and Department of Neurology/Neurosurgery, McGill University, Montreal, Quebec, Canada H3A 2B4
| | - Sandra Minotti
- Montreal Neurological Institute and Department of Neurology/Neurosurgery, McGill University, Montreal, Quebec, Canada H3A 2B4
| | - Wencheng Yang
- Robarts Research Institute, Western University, London, Ontario, Canada N6A 5C1 and
| | - Hongru Zhou
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Michael J Strong
- Robarts Research Institute, Western University, London, Ontario, Canada N6A 5C1 and
| | - Lawrence J Hayward
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Heather D Durham
- Montreal Neurological Institute and Department of Neurology/Neurosurgery, McGill University, Montreal, Quebec, Canada H3A 2B4
| |
Collapse
|
25
|
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.
Collapse
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
| |
Collapse
|
26
|
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: 232] [Impact Index Per Article: 23.2] [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.
Collapse
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.
| |
Collapse
|
27
|
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.
Collapse
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:
| |
Collapse
|
28
|
|
29
|
de Oliveira GP, Alves CJ, Chadi G. Early gene expression changes in spinal cord from SOD1(G93A) Amyotrophic Lateral Sclerosis animal model. Front Cell Neurosci 2013; 7:216. [PMID: 24302897 PMCID: PMC3831149 DOI: 10.3389/fncel.2013.00216] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 10/29/2013] [Indexed: 11/13/2022] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is an adult-onset and fast progression neurodegenerative disease that leads to the loss of motor neurons. Mechanisms of selective motor neuron loss in ALS are unknown. The early events occurring in the spinal cord that may contribute to motor neuron death are not described, neither astrocytes participation in the pre-symptomatic phases of the disease. In order to identify ALS early events, we performed a microarray analysis employing a whole mouse genome platform to evaluate the gene expression pattern of lumbar spinal cords of transgenic SOD1G93A mice and their littermate controls at pre-symptomatic ages of 40 and 80 days. Differentially expressed genes were identified by means of the Bioconductor packages Agi4×44Preprocess and limma. FunNet web based tool was used for analysis of over-represented pathways. Furthermore, immunolabeled astrocytes from 40 and 80 days old mice were submitted to laser microdissection and RNA was extracted for evaluation of a selected gene by qPCR. Statistical analysis has pointed to 492 differentially expressed genes (155 up and 337 down regulated) in 40 days and 1105 (433 up and 672 down) in 80 days old ALS mice. KEGG analysis demonstrated the over-represented pathways tight junction, antigen processing and presentation, oxidative phosphorylation, endocytosis, chemokine signaling pathway, ubiquitin mediated proteolysis and glutamatergic synapse at both pre-symptomatic ages. Ube2i gene expression was evaluated in astrocytes from both transgenic ages, being up regulated in 40 and 80 days astrocytes enriched samples. Our data points to important early molecular events occurring in pre-symptomatic phases of ALS in mouse model. Early SUMOylation process linked to astrocytes might account to non-autonomous cell toxicity in ALS. Further studies on the signaling pathways presented here may provide new insights to better understand the events triggering motor neuron death in this devastating disorder.
Collapse
Affiliation(s)
- Gabriela P de Oliveira
- Department of Neurology, Neuroregeneration Center, University of São Paulo School of Medicine São Paulo, Brazil
| | | | | |
Collapse
|
30
|
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.
Collapse
Affiliation(s)
- Danae Campos-Melo
- Molecular Brain Research Group, Robarts Research Institute, University of Western Ontario, London, ON, Canada
| | | | | | | | | |
Collapse
|
31
|
Robberecht W, Philips T. The changing scene of amyotrophic lateral sclerosis. Nat Rev Neurosci 2013; 14:248-64. [PMID: 23463272 DOI: 10.1038/nrn3430] [Citation(s) in RCA: 745] [Impact Index Per Article: 67.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Several recent breakthroughs have provided notable insights into the pathogenesis of amyotrophic lateral sclerosis (ALS), with some even shifting our thinking about this neurodegenerative disease and raising the question as to whether this disorder is a proteinopathy, a ribonucleopathy or both. In addition, these breakthroughs have revealed mechanistic links between ALS and frontotemporal dementia, as well as between ALS and other neurodegenerative diseases, such as the cerebellar atrophies, myotonic dystrophy and inclusion body myositis. Here, we summarize the new findings in ALS research, discuss what they have taught us about this disease and examine issues that are still outstanding.
Collapse
Affiliation(s)
- Wim Robberecht
- Laboratory of Neurobiology, VIB Vesalius Research Center, 3000 Leuven, Belgium.
| | | |
Collapse
|
32
|
Liu JX, Brännström T, Andersen PM, Pedrosa-Domellöf F. Distinct changes in synaptic protein composition at neuromuscular junctions of extraocular muscles versus limb muscles of ALS donors. PLoS One 2013; 8:e57473. [PMID: 23468993 PMCID: PMC3582511 DOI: 10.1371/journal.pone.0057473] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 01/21/2013] [Indexed: 12/11/2022] Open
Abstract
The pathophysiology of amyotrophic lateral sclerosis (ALS) is very complex and still rather elusive but in recent years evidence of early involvement of the neuromuscular junctions (NMJs) has accumulated. We have recently reported that the human extraocular muscles (EOMs) are far less affected than limb muscles at the end-stage of ALS from the same donor. The present study aimed to compare the differences in synaptic protein composition at NMJ and in nerve fibers between EOM and limb muscles from ALS donors and controls. Neurofilament light subunit and synaptophysin decreased significantly at NMJs and in nerve fibers in limb muscles with ALS whereas they were maintained in ALS EOMs. S100B was significantly decreased at NMJs and in nerve fibers in both EOMs and limb muscles of ALS donors, but other markers confirmed the presence of terminal Schwann cells in these NMJs. p75 neurotrophin receptor was present in nerve fibers but absent at NMJs in ALS limb muscles. The EOMs were able to maintain the integrity of their NMJs to a very large extent until the end-stage of ALS, in contrast to the limb muscles. Changes in Ca2+ homeostasis, reflected by altered S100B distribution, might be involved in the breakdown of nerve-muscle contact at NMJs in ALS.
Collapse
Affiliation(s)
- Jing-Xia Liu
- Department of Integrative Medical Biology, Section for Anatomy, Umeå University, Umeå, Sweden.
| | | | | | | |
Collapse
|
33
|
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.
Collapse
Affiliation(s)
- Cristian A Droppelmann
- Molecular Brain Research Group, Robarts Research Institute , University of Western Ontario, London, Ontario
| | | | | | | | | | | | | |
Collapse
|
34
|
|
35
|
Egawa N, Kitaoka S, Tsukita K, Naitoh M, Takahashi K, Yamamoto T, Adachi F, Kondo T, Okita K, Asaka I, Aoi T, Watanabe A, Yamada Y, Morizane A, Takahashi J, Ayaki T, Ito H, Yoshikawa K, Yamawaki S, Suzuki S, Watanabe D, Hioki H, Kaneko T, Makioka K, Okamoto K, Takuma H, Tamaoka A, Hasegawa K, Nonaka T, Hasegawa M, Kawata A, Yoshida M, Nakahata T, Takahashi R, Marchetto MCN, Gage FH, Yamanaka S, Inoue H. Drug screening for ALS using patient-specific induced pluripotent stem cells. Sci Transl Med 2012; 4:145ra104. [PMID: 22855461 DOI: 10.1126/scitranslmed.3004052] [Citation(s) in RCA: 405] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a late-onset, fatal disorder in which the motor neurons degenerate. The discovery of new drugs for treating ALS has been hampered by a lack of access to motor neurons from ALS patients and appropriate disease models. We generate motor neurons from induced pluripotent stem cells (iPSCs) from familial ALS patients, who carry mutations in Tar DNA binding protein-43 (TDP-43). ALS patient-specific iPSC-derived motor neurons formed cytosolic aggregates similar to those seen in postmortem tissue from ALS patients and exhibited shorter neurites as seen in a zebrafish model of ALS. The ALS motor neurons were characterized by increased mutant TDP-43 protein in a detergent-insoluble form bound to a spliceosomal factor SNRPB2. Expression array analyses detected small increases in the expression of genes involved in RNA metabolism and decreases in the expression of genes encoding cytoskeletal proteins. We examined four chemical compounds and found that a histone acetyltransferase inhibitor called anacardic acid rescued the abnormal ALS motor neuron phenotype. These findings suggest that motor neurons generated from ALS patient-derived iPSCs may provide a useful tool for elucidating ALS disease pathogenesis and for screening drug candidates.
Collapse
Affiliation(s)
- Naohiro Egawa
- Center for iPS Cell Research and Application-CiRA, Kyoto University, Kyoto 606-8507, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
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: 99] [Impact Index Per Article: 8.3] [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.
Collapse
Affiliation(s)
- Brian A Keller
- Department of Pathology, Western University, London, ON, Canada
| | | | | | | | | | | |
Collapse
|
37
|
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: 114] [Impact Index Per Article: 9.5] [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.
Collapse
Affiliation(s)
- Rachel L Redler
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA
| | | |
Collapse
|
38
|
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.
Collapse
Affiliation(s)
- Cristian A Droppelmann
- Molecular Brain Research Group, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
| | | | | | | | | |
Collapse
|
39
|
Kerambrun E, Henry F, Perrichon P, Courcot L, Meziane T, Spilmont N, Amara R. Growth and condition indices of juvenile turbot, Scophthalmus maximus, exposed to contaminated sediments: effects of metallic and organic compounds. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2012; 108:130-140. [PMID: 22265613 DOI: 10.1016/j.aquatox.2011.07.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 07/11/2011] [Accepted: 07/13/2011] [Indexed: 05/31/2023]
Abstract
Since sediments have the potential to form associations with several classes of pollutants, they have been recognized as a possible and significant source of contamination for the benthic environment. Flatfish maintain a close association with sediments for food and cover, and are therefore more likely to be exposed to contaminated sediments, especially in coastal areas (e.g. nursery grounds). The assessment of these potential biological effects involves the use of adapted biomonitoring tools. The main objective of this study was to assess and compare the response of several physiological biomarkers measured on juvenile turbot (Scophthalmus maximus) exposed to contaminated sediments. Sediments were collected from three stations in a harbour in northern France (Boulogne-sur-Mer), in an anthropogenic French estuary (the Seine), and in a reference site (exposed sandy beach of Wimereux). Unexposed lab-reared juvenile turbots were exposed to sediments for 7 and 21 days in laboratory conditions. Sediments were analysed for metals, PAH and PCB contamination. Several fish growth and condition indices were individually analysed in fish according to the chemical contaminant availability in sediment, the metal concentrations in gills and the estimation of PAH metabolites in their bile. Significant decreases in growth rates, morphometric index, RNA:DNA ratio and the lipid storage index, based on the ratio of the quantity of triacylglycerols on sterols (TAG:ST), were observed with increasing level of chemical contamination. This decrease in the fish's physiological status could be related to the significant increase of several metal concentrations in contaminated fish gills and the significant increase of PAH metabolites in bile. In a field situation, such a reduction in growth and energetic status of juvenile fish could dramatically decrease their over-winter survival in contaminated nursery grounds.
Collapse
|
40
|
Liu Q, Xie F, Alvarado-Diaz A, Smith MA, Moreira PI, Zhu X, Perry G. Neurofilamentopathy in neurodegenerative diseases. Open Neurol J 2011; 5:58-62. [PMID: 21915226 PMCID: PMC3170930 DOI: 10.2174/1874205x01105010058] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2011] [Revised: 07/25/2011] [Accepted: 07/28/2011] [Indexed: 12/31/2022] Open
Abstract
Neurofilament protein alterations are found in many neurodegenerative diseases, such as amyotrophic lateral sclerosis, Parkinson, Alzheimer, and Charcot-Marie-Tooth. Abnormal modifications of neurofilament, such as mutation, oxidation and phosphorylation, are linked to the disease-related alteration. In this review, the most recent discovery and central arguments about functions, pathological modifications, and genetic mutations related to neurofilaments in neurodegenerative diseases is presented.
Collapse
Affiliation(s)
- Quan Liu
- School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | | | | | | | | |
Collapse
|
41
|
Long pre-mRNA depletion and RNA missplicing contribute to neuronal vulnerability from loss of TDP-43. Nat Neurosci 2011; 14:459-68. [PMID: 21358643 PMCID: PMC3094729 DOI: 10.1038/nn.2779] [Citation(s) in RCA: 946] [Impact Index Per Article: 72.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 02/14/2011] [Indexed: 12/12/2022]
Abstract
Cross-linking and immunoprecipitation coupled with high-throughput sequencing was used to identify binding sites within 6,304 genes as the brain RNA targets for TDP-43, an RNA binding protein which when mutated causes Amyotrophic Lateral Sclerosis (ALS). Use of massively parallel sequencing and splicing-sensitive junction arrays revealed that levels of 601 mRNAs are changed (including Fus/Tls, progranulin, and other transcripts encoding neurodegenerative disease-associated proteins) and 965 altered splicing events are detected (including in sortilin, the receptor for progranulin), following depletion of TDP-43 from mouse adult brain with antisense oligonucleotides. RNAs whose levels are most depleted by reduction in TDP-43 are derived from genes with very long introns and which encode proteins involved in synaptic activity. Lastly, TDP-43 was found to auto-regulate its synthesis, in part by directly binding and enhancing splicing of an intron within the 3′ untranslated region of its own transcript, thereby triggering nonsense mediated RNA degradation. (147 words)
Collapse
|
42
|
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]
|
43
|
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.
Collapse
|
44
|
McLean J, Liu HN, Miletic D, Weng YC, Rogaeva E, Zinman L, Kriz J, Robertson J. Distinct biochemical signatures characterize peripherin isoform expression in both traumatic neuronal injury and motor neuron disease. J Neurochem 2010; 114:1177-92. [PMID: 20533992 DOI: 10.1111/j.1471-4159.2010.06846.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Peripherin is a type III intermediate filament protein that is up-regulated during neuronal injury and is a major component of pathological inclusions found within degenerating motor neurons of patients with amyotrophic lateral sclerosis (ALS). The relationship between these inclusions and their protein constituents remains largely unknown. We have previously shown that peripherin expression is characterized by tissue-specific, intra-isoform associations that contribute to filament structure; changes to the normal isoform expression pattern is associated with malformed filaments and intracellular inclusions. Here, we profile peripherin isoform expression and ratio changes in traumatic neuronal injury, transgenic mouse models of motor neuron disease, and ALS. Extensive western blot analyses of Triton X-100 soluble and insoluble fractions of neuronal tissue from these conditions revealed significant changes in peripherin isoform content which could be differentiated by electrophoretic banding patterns to produce distinct peripherin biochemical signatures. Significantly, we found that the pattern of peripherin expression in ALS most closely approximates that of peripherin over-expressing mice, but differs with regard to inter-individual variations in isoform-specific expression. Overall, these results provide important insights into complex post-transcriptional processes that may underlie a continuum between peripherin-mediated neuronal repair and its role in the pathogenesis of motor neuron disease.
Collapse
Affiliation(s)
- Jesse McLean
- Department of Laboratory Medicine and Pathobiology, The University of Toronto, Toronto, Ontario, Canada
| | | | | | | | | | | | | | | |
Collapse
|
45
|
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.
Collapse
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
| | | |
Collapse
|
46
|
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.
Collapse
Affiliation(s)
- Michael J Strong
- Molecular Brain Research Group, Robarts Research Institute, London, Ontario, Canada.
| |
Collapse
|
47
|
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.
Collapse
Affiliation(s)
- Kathryn Volkening
- Molecular Brain Research Group, Robarts Research Institute, 100 Perth Drive, London, Ontario, Canada N6A 5K8
| | | | | | | | | |
Collapse
|
48
|
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.
Collapse
Affiliation(s)
- Katie Moisse
- Molecular Brain Research Group, Robarts Research Institute, PO Box 5015, 100 Perth Drive, London ON, Canada
| | | | | | | | | | | |
Collapse
|
49
|
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.
Collapse
Affiliation(s)
- Andrew P Smith
- The Forbes Norris ALS Research Center, California Pacific Medical Center Research Institute, California 94115, USA
| | | |
Collapse
|
50
|
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.
Collapse
Affiliation(s)
- Rodolphe Perrot
- Department of Anatomy and Physiology of Laval University, Centre de Recherche du Centre Hospitalier Universitaire de Québec, Quebec, Canada
| | | |
Collapse
|