1
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Liu M, Duan Y, Dong J, Zhang K, Jin X, Gao M, Jia H, Chen J, Liu M, Wei M, Zhong X. Early signs of neurodegenerative diseases: Possible mechanisms and targets for Golgi stress. Biomed Pharmacother 2024; 175:116646. [PMID: 38692058 DOI: 10.1016/j.biopha.2024.116646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/17/2024] [Accepted: 04/24/2024] [Indexed: 05/03/2024] Open
Abstract
The Golgi apparatus plays a crucial role in mediating the modification, transport, and sorting of intracellular proteins and lipids. The morphological changes occurring in the Golgi apparatus are exceptionally important for maintaining its function. When exposed to external pressure or environmental stimulation, the Golgi apparatus undergoes adaptive changes in both structure and function, which are known as Golgi stress. Although certain signal pathway responses or post-translational modifications have been observed following Golgi stress, further research is needed to comprehensively summarize and understand the related mechanisms. Currently, there is evidence linking Golgi stress to neurodegenerative diseases; however, the role of Golgi stress in the progression of neurodegenerative diseases such as Alzheimer's disease remains largely unexplored. This review focuses on the structural and functional alterations of the Golgi apparatus during stress, elucidating potential mechanisms underlying the involvement of Golgi stress in regulating immunity, autophagy, and metabolic processes. Additionally, it highlights the pivotal role of Golgi stress as an early signaling event implicated in the pathogenesis and progression of neurodegenerative diseases. Furthermore, this study summarizes prospective targets that can be therapeutically exploited to mitigate neurodegenerative diseases by targeting Golgi stress. These findings provide a theoretical foundation for identifying novel breakthroughs in preventing and treating neurodegenerative diseases.
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Affiliation(s)
- Mengyu Liu
- School of Pharmacy, China Medical University, Shenyang, Liaoning 110122, China
| | - Ying Duan
- Liaoning Maternal and Child Health Hospital, Shayang, Liaoning 110005, China
| | - Jianru Dong
- School of Pharmacy, China Medical University, Shenyang, Liaoning 110122, China
| | - Kaisong Zhang
- School of Pharmacy, China Medical University, Shenyang, Liaoning 110122, China
| | - Xin Jin
- School of Pharmacy, China Medical University, Shenyang, Liaoning 110122, China
| | - Menglin Gao
- School of Pharmacy, China Medical University, Shenyang, Liaoning 110122, China
| | - Huachao Jia
- School of Pharmacy, China Medical University, Shenyang, Liaoning 110122, China
| | - Ju Chen
- School of Pharmacy, China Medical University, Shenyang, Liaoning 110122, China
| | - Mingyan Liu
- School of Pharmacy, China Medical University, Shenyang, Liaoning 110122, China.
| | - Minjie Wei
- School of Pharmacy, China Medical University, Shenyang, Liaoning 110122, China; Liaoning Medical Diagnosis and Treatment Center, Shenyang, Liaoning 110167, China.
| | - Xin Zhong
- School of Pharmacy, China Medical University, Shenyang, Liaoning 110122, China.
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2
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Leow DMK, Ng YK, Wang LC, Koh HW, Zhao T, Khong ZJ, Tabaglio T, Narayanan G, Giadone RM, Sobota RM, Ng SY, Teo AKK, Parson SH, Rubin LL, Ong WY, Darras BT, Yeo CJ. Hepatocyte-intrinsic SMN deficiency drives metabolic dysfunction and liver steatosis in spinal muscular atrophy. J Clin Invest 2024; 134:e173702. [PMID: 38722695 PMCID: PMC11178536 DOI: 10.1172/jci173702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 04/25/2024] [Indexed: 06/18/2024] Open
Abstract
Spinal Muscular Atrophy (SMA) is typically characterized as a motor neuron disease, but extra-neuronal phenotypes are present in almost every organ in severely affected patients and animal models. Extra-neuronal phenotypes were previously underappreciated as patients with severe SMA phenotypes usually died in infancy; however, with current treatments for motor neurons increasing patient lifespan, impaired function of peripheral organs may develop into significant future comorbidities and lead to new treatment-modified phenotypes. Fatty liver is seen in SMA animal models , but generalizability to patients and whether this is due to hepatocyte-intrinsic Survival Motor Neuron (SMN) protein deficiency and/or subsequent to skeletal muscle denervation is unknown. If liver pathology in SMA is SMN-dependent and hepatocyte-intrinsic, this suggests SMN repleting therapies must target extra-neuronal tissues and motor neurons for optimal patient outcome. Here we showed that fatty liver is present in SMA and that SMA patient-specific iHeps were susceptible to steatosis. Using proteomics, functional studies and CRISPR/Cas9 gene editing, we confirmed that fatty liver in SMA is a primary SMN-dependent hepatocyte-intrinsic liver defect associated with mitochondrial and other hepatic metabolism implications. These pathologies require monitoring and indicate need for systematic clinical surveillance and additional and/or combinatorial therapies to ensure continued SMA patient health.
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Affiliation(s)
- Damien Meng-Kiat Leow
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Yang Kai Ng
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
| | - Loo Chien Wang
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
| | - Hiromi W.L. Koh
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
| | - Tianyun Zhao
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
| | - Zi Jian Khong
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
| | - Tommaso Tabaglio
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
| | | | - Richard M. Giadone
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge Massachusetts, USA
| | - Radoslaw M. Sobota
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
| | - Shi-Yan Ng
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
- National Neuroscience Institute, Singapore, Singapore
| | - Adrian Kee Keong Teo
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
| | - Simon H. Parson
- Institute of Education in Healthcare and Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, Scotland
| | - Lee L. Rubin
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge Massachusetts, USA
| | - Wei-Yi Ong
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Basil T. Darras
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Crystal J.J. Yeo
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
- Duke-NUS Medical School, Singapore, Singapore
- National Neuroscience Institute, Singapore, Singapore
- Institute of Education in Healthcare and Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, Scotland
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
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3
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Custer SK, Gilson T, Astroski JW, Nanguneri SR, Iurillo AM, Androphy EJ. COPI coatomer subunit α-COP interacts with the RNA binding protein Nucleolin via a C-terminal dilysine motif. Hum Mol Genet 2023; 32:3263-3275. [PMID: 37658769 PMCID: PMC10656708 DOI: 10.1093/hmg/ddad140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 08/07/2023] [Accepted: 08/30/2023] [Indexed: 09/05/2023] Open
Abstract
The COPI coatomer subunit α-COP has been shown to co-precipitate mRNA in multiple settings, but it was unclear whether the interaction with mRNA was direct or mediated by interaction with an adapter protein. The COPI complex often interacts with proteins via C-terminal dilysine domains. A search for candidate RNA binding proteins with C-terminal dilysine motifs yielded Nucleolin, which terminates in a KKxKxx sequence. This protein was an especially intriguing candidate as it has been identified as an interacting partner for Survival Motor Neuron protein (SMN). Loss of SMN causes the neurodegenerative disease Spinal Muscular Atrophy. We have previously shown that SMN and α-COP interact and co-migrate in axons, and that overexpression of α-COP reduced phenotypic severity in cell culture and animal models of SMA. We show here that in an mRNA independent manner, endogenous Nucleolin co-precipitates endogenous α-COP and ε-COP but not β-COP which may reflect an interaction with the so-called B-subcomplex rather a complete COPI heptamer. The ability of Nucleolin to bind to α-COP requires the presence of the C-terminal KKxKxx domain of Nucleolin. Furthermore, we have generated a point mutant in the WD40 domain of α-COP which eliminates its ability to co-precipitate Nucleolin but does not interfere with precipitation of partners mediated by non-KKxKxx motifs such as the kainate receptor subunit 2. We propose that via interaction between the C-terminal dilysine motif of Nucleolin and the WD40 domain of α-COP, Nucleolin acts an adaptor to allow α-COP to interact with a population of mRNA.
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Affiliation(s)
- Sara K Custer
- Dermatology, Indiana University School of Medicine, 545 Barnhill Drive, Emerson Hall 139, Indianapolis, IN 46202, United States
| | - Timra Gilson
- Dermatology, Indiana University School of Medicine, 545 Barnhill Drive, Emerson Hall 139, Indianapolis, IN 46202, United States
| | - Jacob W Astroski
- Dermatology, Indiana University School of Medicine, 545 Barnhill Drive, Emerson Hall 139, Indianapolis, IN 46202, United States
| | - Siddarth R Nanguneri
- Dermatology, Indiana University School of Medicine, 545 Barnhill Drive, Emerson Hall 139, Indianapolis, IN 46202, United States
| | - Alyssa M Iurillo
- Indiana University School of Medicine, 340 West 10 St, Indianapolis, IN 46202, United States
| | - Elliot J Androphy
- Dermatology, Indiana University School of Medicine, 545 Barnhill Drive, Emerson Hall 139, Indianapolis, IN 46202, United States
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4
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Nakevska Z, Yokota T. Challenges and future perspective of antisense therapy for spinal muscular atrophy: A review. Eur J Cell Biol 2023; 102:151326. [PMID: 37295266 DOI: 10.1016/j.ejcb.2023.151326] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 05/18/2023] [Accepted: 05/20/2023] [Indexed: 06/12/2023] Open
Abstract
Spinal muscular atrophy (SMA), the most common genetic cause of infantile death, is caused by a mutation in the survival of motor neuron 1 gene (SMN1), leading to the death of motor neurons and progressive muscle weakness. SMN1 normally produces an essential protein called SMN. Although humans possess a paralogous gene called SMN2, ∼90% of the SMN it produces is non-functional. This is due to a mutation in SMN2 that causes the skipping of a required exon during splicing of the pre-mRNA. The first treatment for SMA, nusinersen (brand name Spinraza), was approved by the FDA in 2016 and by the EMU in 2017. Nusinersen is an antisense oligonucleotide-based therapy that alters the splicing of SMN2 to make functional full-length SMN protein. Despite the recent advancements in antisense oligonucleotide therapy and SMA treatment development, nusinersen is faced with a multitude of challenges, such as intracellular and systemic delivery. In recent years, the use of peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs) in antisense therapy has gained interest. These are antisense oligonucleotides conjugated to cell-penetrating peptides such as Pips and DG9, and they have the potential to address the challenges associated with delivery. This review focuses on the historic milestones, development, current challenges, and future perspectives of antisense therapy for SMA.
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Affiliation(s)
- Zorica Nakevska
- Department of Biological Sciences, Faculty of Science, University of Alberta, 116 St. and 85 Ave., Edmonton AB T6G 2E1, Canada.
| | - Toshifumi Yokota
- Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, 116 St. and 85 Ave., Edmonton AB T6G 2E1, Canada; Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, 116 St. and 85 Ave., Edmonton AB T6G 2E1, Canada; The Friends of Garret Cumming Research and Muscular Dystrophy Canada HM Toupin Neurological Science Research Chair, 8812 112 St., Edmonton AB T6G 2H7, Canada.
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5
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Varderidou-Minasian S, Verheijen BM, Harschnitz O, Kling S, Karst H, van der Pol WL, Pasterkamp RJ, Altelaar M. Spinal Muscular Atrophy Patient iPSC-Derived Motor Neurons Display Altered Proteomes at Early Stages of Differentiation. ACS OMEGA 2021; 6:35375-35388. [PMID: 34984269 PMCID: PMC8717385 DOI: 10.1021/acsomega.1c04688] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 11/24/2021] [Indexed: 05/08/2023]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disorder characterized by loss of motor neurons (MN) in the spinal cord leading to progressive muscle atrophy and weakness. SMA is caused by mutations in the survival motor neuron 1 (SMN1) gene, resulting in reduced levels of survival motor neuron (SMN) protein. The mechanisms that link SMN deficiency to selective motor neuron dysfunction in SMA remain largely unknown. We present here, for the first time, a comprehensive quantitative TMT-10plex proteomics analysis that covers the development of induced pluripotent stem cell-derived MNs from both healthy individuals and SMA patients. We show that the proteomes of SMA samples segregate from controls already at early stages of neuronal differentiation. The altered proteomic signature in SMA MNs is associated with mRNA splicing, ribonucleoprotein biogenesis, organelle organization, cellular biogenesis, and metabolic processes. We highlight several known SMN-binding partners and evaluate their expression changes during MN differentiation. In addition, we compared our study to human and mouse in vivo proteomic studies revealing distinct and similar signatures. Altogether, our work provides a comprehensive resource of molecular events during early stages of MN differentiation, containing potentially therapeutically interesting protein expression profiles for SMA.
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Affiliation(s)
- Suzy Varderidou-Minasian
- Biomolecular
Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular
Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, 3584
CH Utrecht, The Netherlands
- Netherlands
Proteomics Center, Padualaan
8, 3584 CH Utrecht, The Netherlands
| | - Bert M. Verheijen
- Department
of Translational Neuroscience, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CG Utrecht, The Netherlands
- Department
of Neurology and Neurosurgery, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Oliver Harschnitz
- Department
of Translational Neuroscience, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CG Utrecht, The Netherlands
- Department
of Neurology and Neurosurgery, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Sandra Kling
- Department
of Translational Neuroscience, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CG Utrecht, The Netherlands
- Department
of Neurology and Neurosurgery, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Henk Karst
- Department
of Translational Neuroscience, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - W. Ludo van der Pol
- Department
of Neurology and Neurosurgery, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - R. Jeroen Pasterkamp
- Department
of Translational Neuroscience, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Maarten Altelaar
- Biomolecular
Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular
Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, 3584
CH Utrecht, The Netherlands
- Netherlands
Proteomics Center, Padualaan
8, 3584 CH Utrecht, The Netherlands
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6
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Sumoylation regulates the assembly and activity of the SMN complex. Nat Commun 2021; 12:5040. [PMID: 34413305 PMCID: PMC8376998 DOI: 10.1038/s41467-021-25272-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 07/26/2021] [Indexed: 11/09/2022] Open
Abstract
SMN is a ubiquitously expressed protein and is essential for life. SMN deficiency causes the neurodegenerative disease spinal muscular atrophy (SMA), the leading genetic cause of infant mortality. SMN interacts with itself and other proteins to form a complex that functions in the assembly of ribonucleoproteins. SMN is modified by SUMO (Small Ubiquitin-like Modifier), but whether sumoylation is required for the functions of SMN that are relevant to SMA pathogenesis is not known. Here, we show that inactivation of a SUMO-interacting motif (SIM) alters SMN sub-cellular distribution, the integrity of its complex, and its function in small nuclear ribonucleoproteins biogenesis. Expression of a SIM-inactivated mutant of SMN in a mouse model of SMA slightly extends survival rate with limited and transient correction of motor deficits. Remarkably, although SIM-inactivated SMN attenuates motor neuron loss and improves neuromuscular junction synapses, it fails to prevent the loss of sensory-motor synapses. These findings suggest that sumoylation is important for proper assembly and function of the SMN complex and that loss of this post-translational modification impairs the ability of SMN to correct selective deficits in the sensory-motor circuit of SMA mice.
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7
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Blatnik AJ, McGovern VL, Burghes AHM. What Genetics Has Told Us and How It Can Inform Future Experiments for Spinal Muscular Atrophy, a Perspective. Int J Mol Sci 2021; 22:8494. [PMID: 34445199 PMCID: PMC8395208 DOI: 10.3390/ijms22168494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/28/2021] [Accepted: 08/04/2021] [Indexed: 02/06/2023] Open
Abstract
Proximal spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disorder characterized by motor neuron loss and subsequent atrophy of skeletal muscle. SMA is caused by deficiency of the essential survival motor neuron (SMN) protein, canonically responsible for the assembly of the spliceosomal small nuclear ribonucleoproteins (snRNPs). Therapeutics aimed at increasing SMN protein levels are efficacious in treating SMA. However, it remains unknown how deficiency of SMN results in motor neuron loss, resulting in many reported cellular functions of SMN and pathways affected in SMA. Herein is a perspective detailing what genetics and biochemistry have told us about SMA and SMN, from identifying the SMA determinant region of the genome, to the development of therapeutics. Furthermore, we will discuss how genetics and biochemistry have been used to understand SMN function and how we can determine which of these are critical to SMA moving forward.
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Affiliation(s)
| | | | - Arthur H. M. Burghes
- Department of Biological Chemistry & Pharmacology, The Ohio State University Wexner Medical Center, Rightmire Hall, Room 168, 1060 Carmack Road, Columbus, OH 43210, USA; (A.J.B.III); (V.L.M.)
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8
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Astroski JW, Akporyoe LK, Androphy EJ, Custer SK. Mutations in the COPI coatomer subunit α-COP induce release of Aβ-42 and amyloid precursor protein intracellular domain and increase tau oligomerization and release. Neurobiol Aging 2021; 101:57-69. [PMID: 33582567 DOI: 10.1016/j.neurobiolaging.2021.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 12/02/2020] [Accepted: 01/06/2021] [Indexed: 12/14/2022]
Abstract
Understanding the cellular processes that lead to Alzheimer's disease (AD) is critical, and one key lies in the genetics of families with histories of AD. Mutations a complex known as COPI were found in families with AD. The COPI complex is involved in protein processing and trafficking. Intriguingly, several recent publications have found components of the COPI complex can affect the metabolism of pathogenic AD proteins. We reduced levels of the COPI subunit α-COP, altering maturation and cleavage of amyloid precursor protein (APP), resulting in decreased release of Aβ-42 and decreased accumulation of the AICD. Depletion of α-COP reduced uptake of proteopathic Tau seeds and reduces intracellular Tau self-association. Expression of AD-associated mutant α-COP altered APP processing, resulting in increased release of Aβ-42 and increased intracellular Tau aggregation and release of Tau oligomers. These results show that COPI coatomer function modulates processing of both APP and Tau, and expression of AD-associated α-COP confers a toxic gain of function, resulting in potentially pathogenic changes in both APP and Tau.
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Affiliation(s)
- Jacob W Astroski
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - Elliot J Androphy
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Sara K Custer
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA.
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9
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Wang J, Fourriere L, Gleeson PA. Local Secretory Trafficking Pathways in Neurons and the Role of Dendritic Golgi Outposts in Different Cell Models. Front Mol Neurosci 2020; 13:597391. [PMID: 33324160 PMCID: PMC7726432 DOI: 10.3389/fnmol.2020.597391] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 10/19/2020] [Indexed: 12/18/2022] Open
Abstract
A fundamental characteristic of neurons is the relationship between the architecture of the polarized neuron and synaptic transmission between neurons. Intracellular membrane trafficking is paramount to establish and maintain neuronal structure; perturbation in trafficking results in defects in neurodevelopment and neurological disorders. Given the physical distance from the cell body to the distal sites of the axon and dendrites, transport of newly synthesized membrane proteins from the central cell body to their functional destination at remote, distal sites represents a conundrum. With the identification of secretory organelles in dendrites, including endoplasmic reticulum (ER) and Golgi outposts (GOs), recent studies have proposed local protein synthesis and trafficking distinct from the conventional anterograde transport pathways of the cell body. A variety of different model organisms, including Drosophila, zebrafish, and rodents, have been used to probe the organization and function of the local neuronal secretory network. Here, we review the evidence for local secretory trafficking pathways in dendrites in a variety of cell-based neuronal systems and discuss both the similarities and differences in the organization and role of the local secretory organelles, especially the GOs. In addition, we identify the gaps in the current knowledge and the potential advances using human induced pluripotent stem cells (iPSCs) in defining local membrane protein trafficking in human neurons and in understanding the molecular basis of neurological diseases.
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Affiliation(s)
- Jingqi Wang
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Lou Fourriere
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Paul A Gleeson
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
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10
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Blatnik AJ, McGovern VL, Le TT, Iyer CC, Kaspar BK, Burghes AHM. Conditional deletion of SMN in cell culture identifies functional SMN alleles. Hum Mol Genet 2020; 29:3477-3492. [PMID: 33075805 DOI: 10.1093/hmg/ddaa229] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 10/01/2020] [Accepted: 10/12/2020] [Indexed: 12/31/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by mutation or deletion of survival motor neuron 1 (SMN1) and retention of SMN2 leading to SMN protein deficiency. We developed an immortalized mouse embryonic fibroblast (iMEF) line in which full-length wild-type Smn (flwt-Smn) can be conditionally deleted using Cre recombinase. iMEFs lacking flwt-Smn are not viable. We tested the SMA patient SMN1 missense mutation alleles A2G, D44V, A111G, E134K and T274I in these cells to determine which human SMN (huSMN) mutant alleles can function in the absence of flwt-Smn. All missense mutant alleles failed to rescue survival in the conditionally deleted iMEFs. Thus, the function lost by these mutations is essential to cell survival. However, co-expression of two different huSMN missense mutants can rescue iMEF survival and small nuclear ribonucleoprotein (snRNP) assembly, demonstrating intragenic complementation of SMN alleles. In addition, we show that a Smn protein lacking exon 2B can rescue iMEF survival and snRNP assembly in the absence of flwt-Smn, indicating exon 2B is not required for the essential function of Smn. For the first time, using this novel cell line, we can assay the function of SMN alleles in the complete absence of flwt-Smn.
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Affiliation(s)
- Anton J Blatnik
- Ohio State Biochemistry Program.,Biological Chemistry & Pharmacology
| | | | | | | | - Brian K Kaspar
- Center for Gene Therapy, Nationwide Children's Hospital; Department of Pediatrics, College of Medicine and Public Health, The Ohio State University; and Department of Neuroscience, The Ohio State University, Columbus, OH 43210, USA
| | - Arthur H M Burghes
- Ohio State Biochemistry Program.,Biological Chemistry & Pharmacology.,Molecular Genetics.,Department of Neurology, The Ohio State University Wexner Medical Center, Columbus OH 43210 USA
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11
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Jain Goyal M, Zhao X, Bozhinova M, Andrade-López K, de Heus C, Schulze-Dramac S, Müller-McNicoll M, Klumperman J, Béthune J. A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells. Life Sci Alliance 2020; 3:3/9/e202000714. [PMID: 32665377 PMCID: PMC7368096 DOI: 10.26508/lsa.202000714] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 07/06/2020] [Accepted: 07/06/2020] [Indexed: 12/03/2022] Open
Abstract
The paralogous COPI coat subunit γ1-COP plays a unique role in promoting neurite outgrowth during the neuronal differentiation of mouse pluripotent cells. Coat protein complex I (COPI)–coated vesicles mediate membrane trafficking between Golgi cisternae as well as retrieval of proteins from the Golgi to the endoplasmic reticulum. There are several flavors of the COPI coat defined by paralogous subunits of the protein complex coatomer. However, whether paralogous COPI proteins have specific functions is currently unknown. Here, we show that the paralogous coatomer subunits γ1-COP and γ2-COP are differentially expressed during the neuronal differentiation of mouse pluripotent cells. Moreover, through a combination of genome editing experiments, we demonstrate that whereas γ-COP paralogs are largely functionally redundant, γ1-COP specifically promotes neurite outgrowth. Our work stresses a role of the COPI pathway in neuronal polarization and provides evidence for distinct functions for coatomer paralogous subunits in this process.
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Affiliation(s)
- Manu Jain Goyal
- Junior Research Group, Cluster of Excellence CellNetworks, Heidelberg, Germany.,Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Xiyan Zhao
- Junior Research Group, Cluster of Excellence CellNetworks, Heidelberg, Germany.,Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Mariya Bozhinova
- Junior Research Group, Cluster of Excellence CellNetworks, Heidelberg, Germany.,Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Karla Andrade-López
- Junior Research Group, Cluster of Excellence CellNetworks, Heidelberg, Germany.,Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Cecilia de Heus
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Sandra Schulze-Dramac
- RNA Regulation Group, Cluster of Excellence "Macromolecular Complexes," Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Michaela Müller-McNicoll
- RNA Regulation Group, Cluster of Excellence "Macromolecular Complexes," Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Judith Klumperman
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Julien Béthune
- Junior Research Group, Cluster of Excellence CellNetworks, Heidelberg, Germany .,Heidelberg University Biochemistry Center, Heidelberg, Germany
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12
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Baron DM, Matheny T, Lin YC, Leszyk JD, Kenna K, Gall KV, Santos DP, Tischbein M, Funes S, Hayward LJ, Kiskinis E, Landers JE, Parker R, Shaffer SA, Bosco DA. Quantitative proteomics identifies proteins that resist translational repression and become dysregulated in ALS-FUS. Hum Mol Genet 2020; 28:2143-2160. [PMID: 30806671 DOI: 10.1093/hmg/ddz048] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 02/01/2019] [Accepted: 02/07/2019] [Indexed: 12/13/2022] Open
Abstract
Aberrant translational repression is a feature of multiple neurodegenerative diseases. The association between disease-linked proteins and stress granules further implicates impaired stress responses in neurodegeneration. However, our knowledge of the proteins that evade translational repression is incomplete. It is also unclear whether disease-linked proteins influence the proteome under conditions of translational repression. To address these questions, a quantitative proteomics approach was used to identify proteins that evade stress-induced translational repression in arsenite-treated cells expressing either wild-type or amyotrophic lateral sclerosis (ALS)-linked mutant FUS. This study revealed hundreds of proteins that are actively synthesized during stress-induced translational repression, irrespective of FUS genotype. In addition to proteins involved in RNA- and protein-processing, proteins associated with neurodegenerative diseases such as ALS were also actively synthesized during stress. Protein synthesis under stress was largely unperturbed by mutant FUS, although several proteins were found to be differentially expressed between mutant and control cells. One protein in particular, COPBI, was downregulated in mutant FUS-expressing cells under stress. COPBI is the beta subunit of the coat protein I (COPI), which is involved in Golgi to endoplasmic reticulum (ER) retrograde transport. Further investigation revealed reduced levels of other COPI subunit proteins and defects in COPBI-relatedprocesses in cells expressing mutant FUS. Even in the absence of stress, COPBI localization was altered in primary and human stem cell-derived neurons expressing ALS-linked FUS variants. Our results suggest that Golgi to ER retrograde transport may be important under conditions of stress and is perturbed upon the expression of disease-linked proteins such as FUS.
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Affiliation(s)
- Desiree M Baron
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Tyler Matheny
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - Yen-Chen Lin
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA
| | - John D Leszyk
- Department of Biochemistry and Molecular Pharmacology, Worcester, MA, USA.,Mass Spectrometry Facility, University of Massachusetts Medical School, Shrewsbury, MA, USA
| | - Kevin Kenna
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA.,Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands
| | - Katherine V Gall
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA
| | - David P Santos
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.,Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Maeve Tischbein
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Salome Funes
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Lawrence J Hayward
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Evangelos Kiskinis
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.,Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - John E Landers
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Roy Parker
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Scott A Shaffer
- Department of Biochemistry and Molecular Pharmacology, Worcester, MA, USA.,Mass Spectrometry Facility, University of Massachusetts Medical School, Shrewsbury, MA, USA
| | - Daryl A Bosco
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA.,Department of Biochemistry and Molecular Pharmacology, Worcester, MA, USA
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13
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Pushpalatha KV, Besse F. Local Translation in Axons: When Membraneless RNP Granules Meet Membrane-Bound Organelles. Front Mol Biosci 2019; 6:129. [PMID: 31824961 PMCID: PMC6882739 DOI: 10.3389/fmolb.2019.00129] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 11/06/2019] [Indexed: 12/14/2022] Open
Abstract
Eukaryotic cell compartmentalization relies on long-known membrane-delimited organelles, as well as on more recently discovered membraneless macromolecular condensates. How these two types of organelles interact to regulate cellular functions is still largely unclear. In this review, we highlight how membraneless ribonucleoprotein (RNP) organelles, enriched in RNAs and associated regulatory proteins, cooperate with membrane-bound organelles for tight spatio-temporal control of gene expression in the axons of neuronal cells. Specifically, we present recent evidence that motile membrane-bound organelles are used as vehicles by RNP cargoes, promoting the long-range transport of mRNA molecules to distal axons. As demonstrated by recent work, membrane-bound organelles also promote local protein synthesis, by serving as platforms for the local translation of mRNAs recruited to their outer surface. Furthermore, dynamic and specific association between RNP cargoes and membrane-bound organelles is mediated by bi-partite adapter molecules that interact with both types of organelles selectively, in a regulated-manner. Maintaining such a dynamic interplay is critical, as alterations in this process are linked to neurodegenerative diseases. Together, emerging studies thus point to the coordination of membrane-bound and membraneless organelles as an organizing principle underlying local cellular responses.
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Affiliation(s)
| | - Florence Besse
- Université Côte d'Azur, CNRS, Inserm, Institut de Biology Valrose, Nice, France
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14
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Golgi Fragmentation in Neurodegenerative Diseases: Is There a Common Cause? Cells 2019; 8:cells8070748. [PMID: 31331075 PMCID: PMC6679019 DOI: 10.3390/cells8070748] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Revised: 07/17/2019] [Accepted: 07/17/2019] [Indexed: 02/06/2023] Open
Abstract
In most mammalian cells, the Golgi complex forms a continuous ribbon. In neurodegenerative diseases, the Golgi ribbon of a specific group of neurons is typically broken into isolated elements, a very early event which happens before clinical and other pathological symptoms become evident. It is not known whether this phenomenon is caused by mechanisms associated with cell death or if, conversely, it triggers apoptosis. When the phenomenon was studied in diseases such as Parkinson’s and Alzheimer’s or amyotrophic lateral sclerosis, it was attributed to a variety of causes, including the presence of cytoplasmatic protein aggregates, malfunctioning of intracellular traffic and/or alterations in the cytoskeleton. In the present review, we summarize the current findings related to these and other neurodegenerative diseases and try to search for clues on putative common causes.
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15
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Custer SK, Astroski JW, Li HX, Androphy EJ. Interaction between alpha-COP and SMN ameliorates disease phenotype in a mouse model of spinal muscular atrophy. Biochem Biophys Res Commun 2019; 514:530-537. [PMID: 31060774 DOI: 10.1016/j.bbrc.2019.04.176] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 04/26/2019] [Indexed: 11/25/2022]
Abstract
We report that expression of the α-COP protein rescues disease phenotype in a severe mouse model of Spinal Muscular Atrophy (SMA). Lentiviral particles expressing α-COP were injected directly into the testes of genetically pure mouse strain of interest resulting in infection of the spermatagonial stem cells. α-COP was stably expressed in brain, skeletal muscle, and spinal cord without altering SMN protein levels. SMA mice transgenic for α-COP live significantly longer than their non-transgenic littermates, and showed increased body mass and normal muscle morphology at postnatal day 15. We previously reported that binding between SMN and α-COP is required for restoration of neurite outgrowth in cells lacking SMN, and we report similar finding here. Lentiviral-mediated transgenic expression of SMN where the dilysine domain in exon 2b was mutated was not able to rescue the SMA phenotype despite robust expression of the mutant SMN protein in brain, muscle and spinal cord. These results demonstrate that α-COP is a validated modifier of SMA disease phenotype in a mammalian, vertebrate model and is a potential target for development of future SMN-independent therapeutic interventions.
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Affiliation(s)
- Sara K Custer
- Indiana University School of Medicine, Dermatology, Indianapolis, IN, USA.
| | - Jacob W Astroski
- Indiana University School of Medicine, Dermatology, Indianapolis, IN, USA
| | - Hong Xia Li
- Indiana University School of Medicine, Dermatology, Indianapolis, IN, USA
| | - Elliot J Androphy
- Indiana University School of Medicine, Dermatology, Indianapolis, IN, USA
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16
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Šoltić D, Bowerman M, Stock J, Shorrock HK, Gillingwater TH, Fuller HR. Multi-Study Proteomic and Bioinformatic Identification of Molecular Overlap between Amyotrophic Lateral Sclerosis (ALS) and Spinal Muscular Atrophy (SMA). Brain Sci 2018; 8:brainsci8120212. [PMID: 30518112 PMCID: PMC6315439 DOI: 10.3390/brainsci8120212] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 11/28/2018] [Accepted: 11/30/2018] [Indexed: 12/24/2022] Open
Abstract
Unravelling the complex molecular pathways responsible for motor neuron degeneration in amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA) remains a persistent challenge. Interest is growing in the potential molecular similarities between these two diseases, with the hope of better understanding disease pathology for the guidance of therapeutic development. The aim of this study was to conduct a comparative analysis of published proteomic studies of ALS and SMA, seeking commonly dysregulated molecules to be prioritized as future therapeutic targets. Fifteen proteins were found to be differentially expressed in two or more proteomic studies of both ALS and SMA, and bioinformatics analysis identified over-representation of proteins known to associate in vesicles and molecular pathways, including metabolism of proteins and vesicle-mediated transport—both of which converge on endoplasmic reticulum (ER)-Golgi trafficking processes. Calreticulin, a calcium-binding chaperone found in the ER, was associated with both pathways and we independently confirm that its expression was decreased in spinal cords from SMA and increased in spinal cords from ALS mice. Together, these findings offer significant insights into potential common targets that may help to guide the development of new therapies for both diseases.
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Affiliation(s)
- Darija Šoltić
- School of Medicine, Keele University, Staffordshire ST5 5BG, UK; (D.S.); (M.B.)
- Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, UK
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10 7AG, UK
| | - Melissa Bowerman
- School of Medicine, Keele University, Staffordshire ST5 5BG, UK; (D.S.); (M.B.)
- Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, UK
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10 7AG, UK
| | - Joanne Stock
- School of Medicine, Keele University, Staffordshire ST5 5BG, UK; (D.S.); (M.B.)
- Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, UK
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10 7AG, UK
| | - Hannah K. Shorrock
- Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9AG, UK; (H.K.S.); (T.H.G.)
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9AG, UK
| | - Thomas H. Gillingwater
- Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH8 9AG, UK; (H.K.S.); (T.H.G.)
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9AG, UK
| | - Heidi R. Fuller
- School of Medicine, Keele University, Staffordshire ST5 5BG, UK; (D.S.); (M.B.)
- Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, UK
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10 7AG, UK
- Correspondence: ; Tel.: +44-169-140-4693; Fax: +44-169-140-4065
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17
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Custer SK, Foster JN, Astroski JW, Androphy EJ. Abnormal Golgi morphology and decreased COPI function in cells with low levels of SMN. Brain Res 2018; 1706:135-146. [PMID: 30408476 DOI: 10.1016/j.brainres.2018.11.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 11/02/2018] [Accepted: 11/03/2018] [Indexed: 12/13/2022]
Abstract
We report here the finding of abnormal Golgi apparatus morphology in motor neuron like cells depleted of SMN as well as Golgi apparatus morphology in SMA patient fibroblasts. Rescue experiments demonstrate that this abnormality is dependent on SMN, but can also be rescued by expression of the COPI coatomer subunit alpha-COP. A motor neuron-like cell line containing an inducible alpha-COP shRNA was created to generate a parallel system to study knockdown of SMN or alpha-COP. Multiple assays of COPI-dependent intracellular trafficking in cells depleted of SMN demonstrate that alpha-COP function is suboptimal, including failed sequestration of plasma membrane proteins, altered binding of mRNA, and defective targeting and transport of Golgi-resident proteins.
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Affiliation(s)
- S K Custer
- Walther Hall, R3 C636, 980 West Walnut Street, Indianapolis, IN 46202, United States.
| | - J N Foster
- Walther Hall, R3 C636, 980 West Walnut Street, Indianapolis, IN 46202, United States.
| | - J W Astroski
- Walther Hall, R3 C636, 980 West Walnut Street, Indianapolis, IN 46202, United States.
| | - E J Androphy
- Walther Hall, R3 C636, 980 West Walnut Street, Indianapolis, IN 46202, United States.
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18
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Chaytow H, Huang YT, Gillingwater TH, Faller KME. The role of survival motor neuron protein (SMN) in protein homeostasis. Cell Mol Life Sci 2018; 75:3877-3894. [PMID: 29872871 PMCID: PMC6182345 DOI: 10.1007/s00018-018-2849-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 05/30/2018] [Accepted: 05/31/2018] [Indexed: 12/11/2022]
Abstract
Ever since loss of survival motor neuron (SMN) protein was identified as the direct cause of the childhood inherited neurodegenerative disorder spinal muscular atrophy, significant efforts have been made to reveal the molecular functions of this ubiquitously expressed protein. Resulting research demonstrated that SMN plays important roles in multiple fundamental cellular homeostatic pathways, including a well-characterised role in the assembly of the spliceosome and biogenesis of ribonucleoproteins. More recent studies have shown that SMN is also involved in other housekeeping processes, including mRNA trafficking and local translation, cytoskeletal dynamics, endocytosis and autophagy. Moreover, SMN has been shown to influence mitochondria and bioenergetic pathways as well as regulate function of the ubiquitin-proteasome system. In this review, we summarise these diverse functions of SMN, confirming its key role in maintenance of the homeostatic environment of the cell.
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Affiliation(s)
- Helena Chaytow
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Yu-Ting Huang
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK.
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK.
| | - Kiterie M E Faller
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
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19
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Van Alstyne M, Lotti F, Dal Mas A, Area-Gomez E, Pellizzoni L. Stasimon/Tmem41b localizes to mitochondria-associated ER membranes and is essential for mouse embryonic development. Biochem Biophys Res Commun 2018; 506:463-470. [PMID: 30352685 DOI: 10.1016/j.bbrc.2018.10.073] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 10/12/2018] [Indexed: 10/28/2022]
Abstract
Stasimon (also known as Tmem41b) is an evolutionarily conserved transmembrane protein first identified for its contribution to motor system dysfunction in animal models of the childhood neurodegenerative disease spinal muscular atrophy (SMA). Stasimon was shown to be required for normal neurotransmission in the motor circuit of Drosophila larvae and proper development of motor axons in zebrafish embryos as well as to suppress analogous neuronal phenotypes in SMA models of these organisms. However, the subcellular localization and molecular functions of Stasimon are poorly understood. Here, we combined immunoprecipitation with mass spectrometry to characterize the Stasimon interactome in mammalian cells, which reveals association with components of the endoplasmic reticulum (ER), mitochondria, and the COPI vesicle trafficking machinery. Expanding on the interaction results, we used subcellular fractionation studies and super-resolution microscopy to identify Stasimon as an ER-resident protein that localizes at mitochondria-associated ER membranes (MAM), functionally specialized contact sites between ER and mitochondria membranes. Lastly, through characterization of novel knockout mice, we show that Stasimon is an essential gene for mouse embryonic development. Together, these findings identify Stasimon as a novel transmembrane protein component of the MAM with an essential requirement for mammalian development.
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Affiliation(s)
- Meaghan Van Alstyne
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
| | - Francesco Lotti
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
| | - Andrea Dal Mas
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
| | - Estela Area-Gomez
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032, USA; Department of Neurology, Columbia University, New York, NY, 10032, USA
| | - Livio Pellizzoni
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA.
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20
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Khalil B, Morderer D, Price PL, Liu F, Rossoll W. mRNP assembly, axonal transport, and local translation in neurodegenerative diseases. Brain Res 2018; 1693:75-91. [PMID: 29462608 PMCID: PMC5997521 DOI: 10.1016/j.brainres.2018.02.018] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 01/31/2018] [Accepted: 02/13/2018] [Indexed: 12/12/2022]
Abstract
The development, maturation, and maintenance of the mammalian nervous system rely on complex spatiotemporal patterns of gene expression. In neurons, this is achieved by the expression of differentially localized isoforms and specific sets of mRNA-binding proteins (mRBPs) that regulate RNA processing, mRNA trafficking, and local protein synthesis at remote sites within dendrites and axons. There is growing evidence that axons contain a specialized transcriptome and are endowed with the machinery that allows them to rapidly alter their local proteome via local translation and protein degradation. This enables axons to quickly respond to changes in their environment during development, and to facilitate axon regeneration and maintenance in adult organisms. Aside from providing autonomy to neuronal processes, local translation allows axons to send retrograde injury signals to the cell soma. In this review, we discuss evidence that disturbances in mRNP transport, granule assembly, axonal localization, and local translation contribute to pathology in various neurodegenerative diseases, including spinal muscular atrophy (SMA), amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and Alzheimer's disease (AD).
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Affiliation(s)
- Bilal Khalil
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA
| | - Dmytro Morderer
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA
| | - Phillip L Price
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA; Department of Cell Biology, Emory University, Atlanta, GA 30322 USA
| | - Feilin Liu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA; Eye Center, The Second Hospital of Jilin University, Changchun, Jilin 130021, China
| | - Wilfried Rossoll
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA.
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21
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Thompson LW, Morrison KD, Shirran SL, Groen EJN, Gillingwater TH, Botting CH, Sleeman JE. Neurochondrin interacts with the SMN protein suggesting a novel mechanism for spinal muscular atrophy pathology. J Cell Sci 2018; 131:jcs.211482. [PMID: 29507115 PMCID: PMC5963842 DOI: 10.1242/jcs.211482] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 02/16/2018] [Indexed: 12/15/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an inherited neurodegenerative condition caused by a reduction in the amount of functional survival motor neuron (SMN) protein. SMN has been implicated in transport of mRNA in neural cells for local translation. We previously identified microtubule-dependent mobile vesicles rich in SMN and SNRPB, a member of the Sm family of small nuclear ribonucleoprotein (snRNP)-associated proteins, in neural cells. By comparing the interactomes of SNRPB and SNRPN, a neural-specific Sm protein, we now show that the essential neural protein neurochondrin (NCDN) interacts with Sm proteins and SMN in the context of mobile vesicles in neurites. NCDN has roles in protein localisation in neural cells and in maintenance of cell polarity. NCDN is required for the correct localisation of SMN, suggesting they may both be required for formation and transport of trafficking vesicles. NCDN may have potential as a therapeutic target for SMA together with, or in place of the targeting of SMN expression. This article has an associated First Person interview with the first author of the paper. Highlighted Article: The essential neural protein neurochondrin interacts with the spinal muscular atrophy (SMA) protein SMN in cell lines and in mice. This might be relevant to the molecular pathology of SMA.
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Affiliation(s)
- Luke W Thompson
- School of Biology, University of St Andrews, BSRC Complex, North Haugh St Andrews, KY16 9ST, UK
| | - Kim D Morrison
- School of Biology, University of St Andrews, BSRC Complex, North Haugh St Andrews, KY16 9ST, UK
| | - Sally L Shirran
- School of Biology, University of St Andrews, BSRC Complex, North Haugh St Andrews, KY16 9ST, UK
| | - Ewout J N Groen
- Edinburgh Medical School, Biomedical Sciences and Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Thomas H Gillingwater
- Edinburgh Medical School, Biomedical Sciences and Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Catherine H Botting
- School of Biology, University of St Andrews, BSRC Complex, North Haugh St Andrews, KY16 9ST, UK
| | - Judith E Sleeman
- School of Biology, University of St Andrews, BSRC Complex, North Haugh St Andrews, KY16 9ST, UK
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22
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Overlapping Role of SCYL1 and SCYL3 in Maintaining Motor Neuron Viability. J Neurosci 2018; 38:2615-2630. [PMID: 29437892 DOI: 10.1523/jneurosci.2282-17.2018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 12/23/2017] [Accepted: 01/31/2018] [Indexed: 11/21/2022] Open
Abstract
Members of the SCY1-like (SCYL) family of protein kinases are evolutionarily conserved and ubiquitously expressed proteins characterized by an N-terminal pseudokinase domain, centrally located Huntingtin, elongation factor 3, protein phosphatase 2A, yeast kinase TOR1 repeats, and an overall disorganized C-terminal segment. In mammals, three family members encoded by genes Scyl1, Scyl2, and Scyl3 have been described. Studies have pointed to a role for SCYL1 and SCYL2 in regulating neuronal function and viability in mice and humans, but little is known about the biological function of SCYL3. Here, we show that the biochemical and cell biological properties of SCYL3 are similar to those of SCYL1 and both proteins work in conjunction to maintain motor neuron viability. Specifically, although lack of Scyl3 in mice has no apparent effect on embryogenesis and postnatal life, it accelerates the onset of the motor neuron disorder caused by Scyl1 deficiency. Growth abnormalities, motor dysfunction, hindlimb paralysis, muscle wasting, neurogenic atrophy, motor neuron degeneration, and loss of large-caliber axons in peripheral nerves occurred at an earlier age in Scyl1/Scyl3 double-deficient mice than in Scyl1-deficient mice. Disease onset also correlated with the mislocalization of TDP-43 in spinal motor neurons, suggesting that SCYL1 and SCYL3 regulate TDP-43 proteostasis. Together, our results demonstrate an overlapping role for SCYL1 and SCYL3 in vivo and highlight the importance the SCYL family of proteins in regulating neuronal function and survival. Only male mice were used in this study.SIGNIFICANCE STATEMENT SCYL1 and SCYL2, members of the SCY1-like family of pseudokinases, have well established roles in neuronal function. Herein, we uncover the role of SCYL3 in maintaining motor neuron viability. Although targeted disruption of Scyl3 in mice had little or no effect on embryonic development and postnatal life, it accelerated disease onset associated with the loss of Scyl1, a novel motor neuron disease gene in humans. Scyl1 and Scyl3 double-deficient mice had neuronal defects characteristic of amyotrophic lateral sclerosis, including TDP-43 pathology, at an earlier age than did Scyl1-deficient mice. Thus, we show that SCYL1 and SCYL3 play overlapping roles in maintaining motor neuronal viability in vivo and confirm that SCYL family members are critical regulators of neuronal function and survival.
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23
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Identification and expression profile of an alpha-COPI homologous gene (COPA1) involved in high irradiance and salinity stress in Haematococcus pluvialis. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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24
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Nash LA, McFall ER, Perozzo AM, Turner M, Poulin KL, De Repentigny Y, Burns JK, McMillan HJ, Warman Chardon J, Burger D, Kothary R, Parks RJ. Survival Motor Neuron Protein is Released from Cells in Exosomes: A Potential Biomarker for Spinal Muscular Atrophy. Sci Rep 2017; 7:13859. [PMID: 29066780 PMCID: PMC5655039 DOI: 10.1038/s41598-017-14313-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 10/06/2017] [Indexed: 11/09/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by homozygous mutation of the survival motor neuron 1 (SMN1) gene. Disease severity inversely correlates to the amount of SMN protein produced from the homologous SMN2 gene. We show that SMN protein is naturally released in exosomes from all cell types examined. Fibroblasts from patients or a mouse model of SMA released exosomes containing reduced levels of SMN protein relative to normal controls. Cells overexpressing SMN protein released exosomes with dramatically elevated levels of SMN protein. We observed enhanced quantities of exosomes in the medium from SMN-depleted cells, and in serum from a mouse model of SMA and a patient with Type 3 SMA, suggesting that SMN-depletion causes a deregulation of exosome release or uptake. The quantity of SMN protein contained in the serum-derived exosomes correlated with the genotype of the animal, with progressively less protein in carrier and affected animals compared to wildtype mice. SMN protein was easily detectable in exosomes isolated from human serum, with a reduction in the amount of SMN protein in exosomes from a patient with Type 3 SMA compared to a normal control. Our results suggest that exosome-derived SMN protein may serve as an effective biomarker for SMA.
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Affiliation(s)
- Leslie A Nash
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Emily R McFall
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Amanda M Perozzo
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Maddison Turner
- Kidney Research Centre, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Kathy L Poulin
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Yves De Repentigny
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Joseph K Burns
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Hugh J McMillan
- University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada.,Department of Pediatrics, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, Canada.,Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada
| | - Jodi Warman Chardon
- University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada.,Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada.,Division of Neurogenetics, Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Canada.,Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Dylan Burger
- Kidney Research Centre, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada.,Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Robin J Parks
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada. .,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada. .,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada. .,Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
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25
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Hosseinibarkooie S, Schneider S, Wirth B. Advances in understanding the role of disease-associated proteins in spinal muscular atrophy. Expert Rev Proteomics 2017. [PMID: 28635376 DOI: 10.1080/14789450.2017.1345631] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
INTRODUCTION Spinal muscular atrophy (SMA) is a neurodegenerative disorder characterized by alpha motor neuron loss in the spinal cord due to reduced survival motor neuron (SMN) protein level. While the genetic basis of SMA is well described, the specific molecular pathway underlying SMA is still not fully understood. Areas covered: This review discusses the recent advancements in understanding the molecular pathways in SMA using different omics approaches and genetic modifiers identified in both vertebrate and invertebrate systems. The findings that are summarized in this article were deduced from original articles and reviews with a particular focus on the latest advancements in the field. Expert commentary: The identification of genetic modifiers such as PLS3 and NCALD in humans or of SMA modulators such as Elavl4 (HuD), Copa, Uba1, Mapk10 (Jnk3), Nrxn2 and Tmem41b (Stasimon) in various SMA animal models improved our knowledge of impaired cellular pathways in SMA. Inspiration from modifier genes and their functions in motor neuron and neuromuscular junctions may open a new avenue for future SMA combinatorial therapies.
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Affiliation(s)
- Seyyedmohsen Hosseinibarkooie
- a Institute of Human Genetics , University of Cologne , Cologne , Germany.,b Center for Molecular Medicine Cologne , University of Cologne , Cologne , Germany.,c Institute for Genetics , University of Cologne , Cologne , Germany
| | - Svenja Schneider
- a Institute of Human Genetics , University of Cologne , Cologne , Germany.,b Center for Molecular Medicine Cologne , University of Cologne , Cologne , Germany.,c Institute for Genetics , University of Cologne , Cologne , Germany
| | - Brunhilde Wirth
- a Institute of Human Genetics , University of Cologne , Cologne , Germany.,b Center for Molecular Medicine Cologne , University of Cologne , Cologne , Germany.,c Institute for Genetics , University of Cologne , Cologne , Germany.,d Center for Rare Diseases Cologne , University Hospital of Cologne, University of Cologne , Cologne , Germany
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26
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Singh RN, Howell MD, Ottesen EW, Singh NN. Diverse role of survival motor neuron protein. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2017; 1860:299-315. [PMID: 28095296 PMCID: PMC5325804 DOI: 10.1016/j.bbagrm.2016.12.008] [Citation(s) in RCA: 189] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 12/23/2016] [Accepted: 12/30/2016] [Indexed: 02/07/2023]
Abstract
The multifunctional Survival Motor Neuron (SMN) protein is required for the survival of all organisms of the animal kingdom. SMN impacts various aspects of RNA metabolism through the formation and/or interaction with ribonucleoprotein (RNP) complexes. SMN regulates biogenesis of small nuclear RNPs, small nucleolar RNPs, small Cajal body-associated RNPs, signal recognition particles and telomerase. SMN also plays an important role in DNA repair, transcription, pre-mRNA splicing, histone mRNA processing, translation, selenoprotein synthesis, macromolecular trafficking, stress granule formation, cell signaling and cytoskeleton maintenance. The tissue-specific requirement of SMN is dictated by the variety and the abundance of its interacting partners. Reduced expression of SMN causes spinal muscular atrophy (SMA), a leading genetic cause of infant mortality. SMA displays a broad spectrum ranging from embryonic lethality to an adult onset. Aberrant expression and/or localization of SMN has also been associated with male infertility, inclusion body myositis, amyotrophic lateral sclerosis and osteoarthritis. This review provides a summary of various SMN functions with implications to a better understanding of SMA and other pathological conditions.
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Affiliation(s)
- Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States.
| | - Matthew D Howell
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
| | - Eric W Ottesen
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
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27
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Altered mRNA Splicing in SMN-Depleted Motor Neuron-Like Cells. PLoS One 2016; 11:e0163954. [PMID: 27736905 PMCID: PMC5063418 DOI: 10.1371/journal.pone.0163954] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 09/16/2016] [Indexed: 11/23/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an intractable neurodegenerative disease afflicting 1 in 6–10,000 live births. One of the key functions of the SMN protein is regulation of spliceosome assembly. Reduced levels of the SMN protein that are observed in SMA have been shown to result in aberrant mRNA splicing. SMN-dependent mis-spliced transcripts in motor neurons may cause stresses that are particularly harmful and may serve as potential targets for the treatment of motor neuron disease or as biomarkers in the SMA patient population. We performed deep RNA sequencing using motor neuron-like NSC-34 cells to screen for SMN-dependent mRNA processing changes that occur following acute depletion of SMN. We identified SMN-dependent splicing changes, including an intron retention event that results in the production of a truncated Rit1 transcript. This intron-retained transcript is stable and is mis-spliced in spinal cord from symptomatic SMA mice. Constitutively active Rit1 ameliorated the neurite outgrowth defect in SMN depleted NSC-34 cells, while expression of the truncated protein product of the mis-spliced Rit1 transcript inhibited neurite extension. These results reveal new insights into the biological consequence of SMN-dependent splicing in motor neuron-like cells.
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28
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Garcia EL, Wen Y, Praveen K, Matera AG. Transcriptomic comparison of Drosophila snRNP biogenesis mutants reveals mutant-specific changes in pre-mRNA processing: implications for spinal muscular atrophy. RNA (NEW YORK, N.Y.) 2016; 22:1215-1227. [PMID: 27268418 PMCID: PMC4931114 DOI: 10.1261/rna.057208.116] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 05/12/2016] [Indexed: 06/06/2023]
Abstract
Survival motor neuron (SMN) functions in the assembly of spliceosomal small nuclear ribonucleoproteins (snRNPs) that catalyze pre-mRNA splicing. Here, we used disruptions in Smn and two additional snRNP biogenesis genes, Phax and Ars2, to classify RNA processing differences as snRNP-dependent or gene-specific in Drosophila Phax and Smn mutants exhibited comparable reductions in snRNAs, and comparison of their transcriptomes uncovered shared sets of RNA processing changes. In contrast, Ars2 mutants displayed only small decreases in snRNA levels, and RNA processing changes in these mutants were generally distinct from those identified in Phax and Smn animals. Instead, RNA processing changes in Ars2 mutants support the known interaction of Ars2 protein with the cap-binding complex, as splicing changes showed a clear bias toward the first intron. Bypassing disruptions in snRNP biogenesis, direct knockdown of spliceosomal proteins caused similar changes in the splicing of snRNP-dependent events. However, these snRNP-dependent events were largely unaltered in three Smn mutants expressing missense mutations that were originally identified in human spinal muscular atrophy (SMA) patients. Hence, findings here clarify the contributions of Phax, Smn, and Ars2 to snRNP biogenesis in Drosophila, and loss-of-function mutants for these proteins reveal differences that help disentangle cause and effect in SMA model flies.
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Affiliation(s)
- Eric L Garcia
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Ying Wen
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Kavita Praveen
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - A Gregory Matera
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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29
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Donlin-Asp PG, Bassell GJ, Rossoll W. A role for the survival of motor neuron protein in mRNP assembly and transport. Curr Opin Neurobiol 2016; 39:53-61. [PMID: 27131421 DOI: 10.1016/j.conb.2016.04.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 03/27/2016] [Accepted: 04/13/2016] [Indexed: 02/08/2023]
Abstract
Localization and local translation of mRNA plays a key role in neuronal development and function. While studies in various systems have provided insights into molecular mechanisms of mRNA transport and local protein synthesis, the factors that control the assembly of mRNAs and mRNA binding proteins into messenger ribonucleoprotein (mRNP) transport granules remain largely unknown. In this review we will discuss how insights on a motor neuron disease, spinal muscular atrophy (SMA), is advancing our understanding of regulated assembly of transport competent mRNPs and how defects in their assembly and delivery may contribute to the degeneration of motor neurons observed in SMA and other neurological disorders.
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Affiliation(s)
- Paul G Donlin-Asp
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA; Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA.
| | - Wilfried Rossoll
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA.
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