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De Ritis D, Ferrè L, De Winter J, Tremblay-Desbiens C, Blais M, Bassi MT, Dupré N, Baets J, Filippi M, Maltecca F. Reduction of sacsin levels in peripheral blood mononuclear cells as a diagnostic tool for spastic ataxia of Charlevoix-Saguenay. Brain Commun 2024; 6:fcae243. [PMID: 39091421 PMCID: PMC11291951 DOI: 10.1093/braincomms/fcae243] [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: 05/03/2024] [Revised: 06/26/2024] [Accepted: 07/17/2024] [Indexed: 08/04/2024] Open
Abstract
Autosomal recessive spastic ataxia of Charlevoix-Saguenay is a rare neurodegenerative disease caused by biallelic variants in the SACS gene encoding for sacsin. More than 200 pathogenic variants have been identified to date, most of which are missense. It is likely that the prevalence of autosomal recessive spastic ataxia of Charlevoix-Saguenay is underestimated due to the lack of an efficient diagnostic tool able to validate variants of uncertain significance. We have previously shown that sacsin is almost absent in fibroblasts of patients with autosomal recessive spastic ataxia of Charlevoix-Saguenay regardless of the type of SACS variant, because sacsin carrying missense variants is cotranslationally degraded. In this work, we aimed to establish the pathogenicity of SACS variants by quantifying sacsin protein in blood samples, with relevant implications for autosomal recessive spastic ataxia of Charlevoix-Saguenay diagnosis. We developed a protocol to assess sacsin protein levels by western blot using small amounts of peripheral blood mononuclear cells, which can be propagated in culture and cryopreserved. The study involves eight patients with autosomal recessive spastic ataxia of Charlevoix-Saguenay (including a novel case) carrying variants of different types and positions along the SACS gene and two parents who are carriers of heterozygous missense variants. We show that patients with autosomal recessive spastic ataxia of Charlevoix-Saguenay (carrying either missense or truncating variants) almost completely lacked sacsin in peripheral blood mononuclear cells. Moreover, both carriers of a SACS missense variant showed 50% reduction in sacsin protein levels compared to controls. We also describe a patient with uniparental isodisomy carrying a homozygous nonsense variant near the 3' end of the SACS gene. This resulted in a stable sacsin protein lacking the last 202 amino acids, probably due to escape of nonsense-mediated decay of mRNA. In conclusion, we have optimized a minimally invasive diagnostic tool for autosomal recessive spastic ataxia of Charlevoix-Saguenay in blood samples based on sacsin protein level assessment. Indeed, our results provide definite evidence that sacsin carrying missense pathogenic variants undergoes cotranslational degradation. The quantitative reduction in sacsin levels in the case of missense variants of uncertain significance allows defining them as pathogenic variants, something which cannot be predicted bioinformatically with high certainty.
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Affiliation(s)
- Daniele De Ritis
- Mitochondrial Dysfunctions in Neurodegeneration Unit, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Laura Ferrè
- Department of Neurology, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Jonathan De Winter
- Institute Born-Bunge and Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, 2610 Antwerp, Belgium
- Department of Neurology, Neuromuscular Reference Centre, Antwerp University Hospital, 2610 Antwerp, Belgium
| | | | - Mathieu Blais
- Neuroscience Axis, CHU de Québec, Université Laval, Quebec City, QC G1V 0A6, Canada
| | - Maria Teresa Bassi
- Laboratory of Medical Genetics, Scientific Institute, IRCCS E. Medea, 23842 Bosisio Parini, Italy
| | - Nicolas Dupré
- Neuroscience Axis, CHU de Québec, Université Laval, Quebec City, QC G1V 0A6, Canada
- Department of Medicine, Faculty of Medicine, Université Laval, Quebec City, QC G1V 0A6, Canada
| | - Jonathan Baets
- Institute Born-Bunge and Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, 2610 Antwerp, Belgium
- Department of Neurology, Neuromuscular Reference Centre, Antwerp University Hospital, 2610 Antwerp, Belgium
| | - Massimo Filippi
- Department of Neurology, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
- Università Vita-Salute San Raffaele, 20132 Milan, Italy
| | - Francesca Maltecca
- Mitochondrial Dysfunctions in Neurodegeneration Unit, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
- Università Vita-Salute San Raffaele, 20132 Milan, Italy
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2
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Scaravilli A, Gabusi I, Mari G, Battocchio M, Bosticardo S, Schiavi S, Bender B, Kessler C, Brais B, La Piana R, van de Warrenburg BP, Cosottini M, Timmann D, Daducci A, Schüle R, Synofzik M, Santorelli FM, Cocozza S. An MRI evaluation of white matter involvement in paradigmatic forms of spastic ataxia: results from the multi-center PROSPAX study. J Neurol 2024:10.1007/s00415-024-12505-y. [PMID: 38880819 DOI: 10.1007/s00415-024-12505-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/04/2024] [Accepted: 06/07/2024] [Indexed: 06/18/2024]
Abstract
BACKGROUND Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS) and Spastic Paraplegia Type 7 (SPG7) are paradigmatic spastic ataxias (SPAX) with suggested white matter (WM) involvement. Aim of this work was to thoroughly disentangle the degree of WM involvement in these conditions, evaluating both macrostructure and microstructure via the analysis of diffusion MRI (dMRI) data. MATERIAL AND METHODS In this multi-center prospective study, ARSACS and SPG7 patients and Healthy Controls (HC) were enrolled, all undergoing a standardized dMRI protocol and a clinimetrics evaluation including the Scale for the Assessment and Rating of Ataxia (SARA). Differences in terms of WM volume or global microstructural WM metrics were probed, as well as the possible occurrence of a spatially defined microstructural WM involvement via voxel-wise analyses, and its correlation with patients' clinical status. RESULTS Data of 37 ARSACS (M/F = 21/16; 33.4 ± 12.4 years), 37 SPG7 (M/F = 24/13; 55.7 ± 10.7 years), and 29 HC (M/F = 13/16; 42.1 ± 17.2 years) were analyzed. While in SPG7, only a mild mean microstructural damage was found compared to HC, ARSACS patients present a severe WM involvement, with a reduced global volume (p < 0.001), an alteration of all microstructural metrics (all with p < 0.001), without a spatially defined pattern of damage but with a prominent involvement of commissural fibers. Finally, in ARSACS, a correlation between microstructural damage and SARA scores was found (p = 0.004). CONCLUSION In ARSACS, but not SPG7 patients, we observed a complex and multi-faced involvement of brain WM, with a clinically meaningful widespread loss of axonal and dendritic integrity, secondary demyelination and, overall, a reduction in cellularity and volume.
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Affiliation(s)
- Alessandra Scaravilli
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini 5, 80131, Naples, Italy
| | - Ilaria Gabusi
- Department of Computer Science, Diffusion Imaging and Connectivity Estimation (DICE) Lab, University of Verona, Verona, Italy
| | - Gaia Mari
- Department of Computer Science, Diffusion Imaging and Connectivity Estimation (DICE) Lab, University of Verona, Verona, Italy
| | - Matteo Battocchio
- Department of Computer Science, Diffusion Imaging and Connectivity Estimation (DICE) Lab, University of Verona, Verona, Italy
| | - Sara Bosticardo
- Department of Computer Science, Diffusion Imaging and Connectivity Estimation (DICE) Lab, University of Verona, Verona, Italy
| | - Simona Schiavi
- Department of Computer Science, Diffusion Imaging and Connectivity Estimation (DICE) Lab, University of Verona, Verona, Italy
| | - Benjamin Bender
- Department of Diagnostic and Interventional Neuroradiology, University of Tübingen, Tübingen, Germany
| | - Christoph Kessler
- Center for Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Bernard Brais
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Roberta La Piana
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Canada
- Department of Diagnostic Radiology, McGill University, Montreal, Canada
| | - Bart P van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Mirco Cosottini
- Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Dagmar Timmann
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), Essen University Hospital, Essen, Germany
| | - Alessandro Daducci
- Department of Computer Science, Diffusion Imaging and Connectivity Estimation (DICE) Lab, University of Verona, Verona, Italy
| | - Rebecca Schüle
- Center for Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
- Division of Neurodegenerative Diseases, Department of Neurology, Heidelberg University Hospital and Faculty of Medicine, Heidelberg, Germany
| | - Matthis Synofzik
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
- Division Translational Genomics of Neurodegenerative Diseases, Center for Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | | | - Sirio Cocozza
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini 5, 80131, Naples, Italy.
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Kim D, Ryoo N, Park YH, Bagyinszky E, An SSA, Kim S. A Novel Mutation in Sacsin, p.Val1335IIe, May Cause Late-Onset Sacsinopathy Due to Haploinsufficiency. Curr Issues Mol Biol 2023; 45:9917-9925. [PMID: 38132465 PMCID: PMC10741900 DOI: 10.3390/cimb45120619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 12/23/2023] Open
Abstract
Autosomal recessive spastic ataxia in Charlevoix-Saguenay (ARSACS) is a neurodegenerative disorder caused by mutations in the sacsin molecular chaperone protein (SACS) gene. Since the first report from Quebec in 1978, many pathogenic ARSACS variants with significantly reduced chaperone activities have been reported worldwide in adolescents, with presumably altered protein folding. In this study, a novel SACS mutation (p.Val1335IIe, Heterozygous) was identified in a Korean patient in their 50s with late-onset ARSACS characterized by cerebellar ataxia and spasticity without peripheral neuropathy. The mutation was confirmed via whole exome sequencing and Sanger sequencing and was predicted to likely cause disease using prediction software. RT-PCR and ELISA showed decreased SACS mRNA expression and sacsin protein concentrations in the proband, supporting its implications in diseases with pathogenicity and reduced chaperone function from haploinsufficiency. Our results revealed the pathogenicity of the SACS Val1335IIe mutation in the proband patient's disease manifestation, even though the symptoms had a limited correlation with the typical ARSACS clinical triad, which could be due to the reduced chaperon function from haploinsufficiency. Furthermore, our study suggests that variants of SACS heterozygosity may have diverse symptoms, with a wide range of disease onsets for late-onset sacsinopathy.
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Affiliation(s)
- Danyeong Kim
- Department of Bionano Technology, Gachon University, Seongnam 13120, Republic of Korea;
| | - Nayoung Ryoo
- Department of Neurology, Eunpyeong St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul 03083, Republic of Korea;
| | - Young Ho Park
- Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea;
| | - Eva Bagyinszky
- Graduate School of Industrial and Environmental Engineering, Gachon University, Seongnam 13120, Republic of Korea;
| | | | - SangYun Kim
- Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea;
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4
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Ekenstedt KJ, Minor KM, Shelton GD, Hammond JJ, Miller AD, Taylor SM, Huang Y, Mickelson JR. A SACS deletion variant in Great Pyrenees dogs causes autosomal recessive neuronal degeneration. Hum Genet 2023; 142:1587-1601. [PMID: 37758910 PMCID: PMC10602964 DOI: 10.1007/s00439-023-02599-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023]
Abstract
ARSACS (autosomal recessive spastic ataxia of Charlevoix-Saguenay) is a human neurological disorder characterized by progressive cerebellar ataxia and peripheral neuropathy. A recently recognized disorder in Great Pyrenees dogs is similarly characterized by widespread central nervous system degeneration leading to progressive cerebellar ataxia and spasticity, combined with peripheral neuropathy. Onset of clinical signs occurred in puppies as young as 4 months of age, with slow progression over several years. A multi-generation pedigree suggested an autosomal recessive mode of inheritance. Histopathology revealed consistent cerebellar Purkinje cell degeneration, neuronal degeneration in brainstem nuclei, widespread spinal cord white matter degeneration, ganglion cell degeneration, inappropriately thin myelin sheaths or fully demyelinated peripheral nerve fibers, and normal or only mild patterns of denervation atrophy in skeletal muscles. Genome-wide single nucleotide polymorphism (SNP) genotype data was collected from 6 cases and 26 controls, where homozygosity mapping identified a 3.3 Mb region on CFA25 in which all cases were homozygous and all controls were either heterozygous or homozygous for alternate haplotypes. This region tagged the SACS gene where variants are known to cause ARSACS. Sanger sequencing of SACS in affected dogs identified a 4 bp deletion that causes a frame shift and truncates 343 amino acids from the C terminus of the encoded sacsin protein (p.Val4244AlafsTer32). Our clinical and histopathological descriptions of this canine disorder contribute to the description of human ARSACS and represents the first naturally occurring large animal model of this disorder.
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Affiliation(s)
- Kari J Ekenstedt
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, Lynn Hall, 625 Harrison Street, West Lafayette, IN, 47907, USA.
| | - Katie M Minor
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, 55108, USA
| | - G Diane Shelton
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - James J Hammond
- Department of Neurology, Pieper Memorial Veterinary Center, Middletown, CT, 06457, USA
| | - Andrew D Miller
- Section of Anatomic Pathology, Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA
| | - Susan M Taylor
- Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, S7N 5B4, Canada
| | - Yanyun Huang
- Prairie Diagnostic Services, Inc., Saskatoon, SK, S7N 5B4, Canada
| | - James R Mickelson
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, 55108, USA
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5
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Márquez BT, Leung TCS, Hui J, Charron F, McKinney RA, Watt AJ. A mitochondrial-targeted antioxidant (MitoQ) improves motor coordination and reduces Purkinje cell death in a mouse model of ARSACS. Neurobiol Dis 2023; 183:106157. [PMID: 37209925 DOI: 10.1016/j.nbd.2023.106157] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 05/10/2023] [Accepted: 05/17/2023] [Indexed: 05/22/2023] Open
Abstract
Mitochondrial deficits have been observed in animal models of Autosomal-recessive spastic ataxia of the Charlevoix-Saguenay (ARSACS) and in patient-derived fibroblasts. We investigated whether mitochondrial function could be restored in Sacs-/- mice, a mouse model of ARSACS, using the mitochondrial-targeted antioxidant ubiquinone MitoQ. After 10 weeks of chronic MitoQ administration in drinking water, we partially reversed motor coordination deficits in Sacs-/- mice but did not affect litter-matched wild-type control mice. MitoQ administration led to a restoration of superoxide dismutase 2 (SOD2) in cerebellar Purkinje cell somata without altering Purkinje cell firing deficits. Purkinje cells in anterior vermis of Sacs-/- mice normally undergo cell death in ARSACS; however, Purkinje cells numbers were elevated after chronic MitoQ treatment. Furthermore, Purkinje cell innervation of target neurons in the cerebellar nuclei of Sacs-/- mice were also partially restored with MitoQ treatment. Our data suggest that MitoQ is a potential therapeutic treatment for ARSACS and that it improves motor coordination via increasing cerebellar Purkinje cell mitochondria function and reducing Purkinje cell death.
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Affiliation(s)
| | | | - Jeanette Hui
- Department of Biology, McGill University, Montreal, QC, Canada
| | - François Charron
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - R Anne McKinney
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada.
| | - Alanna J Watt
- Department of Biology, McGill University, Montreal, QC, Canada.
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6
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Louit A, Beaudet MJ, Blais M, Gros-Louis F, Dupré N, Berthod F. In Vitro Characterization of Motor Neurons and Purkinje Cells Differentiated from Induced Pluripotent Stem Cells Generated from Patients with Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay. Stem Cells Int 2023; 2023:1496597. [PMID: 37096129 PMCID: PMC10122584 DOI: 10.1155/2023/1496597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 03/27/2023] [Accepted: 03/28/2023] [Indexed: 04/26/2023] Open
Abstract
Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is an early-onset neurodegenerative disease mainly characterized by spasticity in the lower limbs and poor muscle control. The disease is caused by mutations in the SACS gene leading in most cases to a loss of function of the sacsin protein, which is highly expressed in motor neurons and Purkinje cells. To investigate the impact of the mutated sacsin protein in these cells in vitro, induced pluripotent stem cell- (iPSC-) derived motor neurons and iPSC-derived Purkinje cells were generated from three ARSACS patients. Both types of iPSC-derived neurons expressed the characteristic neuronal markers β3-tubulin, neurofilaments M and H, as well as specific markers like Islet-1 for motor neurons, and parvalbumin or calbindin for Purkinje cells. Compared to controls, iPSC-derived mutated SACS neurons expressed lower amounts of sacsin. In addition, characteristic neurofilament aggregates were detected along the neurites of both iPSC-derived neurons. These results indicate that it is possible to recapitulate in vitro, at least in part, the ARSACS pathological signature in vitro using patient-derived motor neurons and Purkinje cells differentiated from iPSCs. Such an in vitro personalized model of the disease could be useful for the screening of new drugs for the treatment of ARSACS.
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Affiliation(s)
- Aurélie Louit
- LOEX, Centre de recherche du CHU de Québec-Université Laval, Quebec City, Quebec, Canada
| | - Marie-Josée Beaudet
- LOEX, Centre de recherche du CHU de Québec-Université Laval, Quebec City, Quebec, Canada
| | - Mathieu Blais
- LOEX, Centre de recherche du CHU de Québec-Université Laval, Quebec City, Quebec, Canada
| | - François Gros-Louis
- LOEX, Centre de recherche du CHU de Québec-Université Laval, Quebec City, Quebec, Canada
- Department of Surgery, Faculty of Medicine, Université Laval, Quebec City, Quebec, Canada
| | - Nicolas Dupré
- LOEX, Centre de recherche du CHU de Québec-Université Laval, Quebec City, Quebec, Canada
- Department of Medicine, Faculty of Medicine, Université Laval, Quebec City, Quebec, Canada
| | - François Berthod
- LOEX, Centre de recherche du CHU de Québec-Université Laval, Quebec City, Quebec, Canada
- Department of Surgery, Faculty of Medicine, Université Laval, Quebec City, Quebec, Canada
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7
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Aly KA, Moutaoufik MT, Zilocchi M, Phanse S, Babu M. Insights into SACS pathological attributes in autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS)☆. Curr Opin Chem Biol 2022; 71:102211. [PMID: 36126381 DOI: 10.1016/j.cbpa.2022.102211] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 07/22/2022] [Accepted: 08/10/2022] [Indexed: 01/27/2023]
Abstract
Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a rare early-onset neurodegenerative disease caused by mutations in the SACS gene, encoding Sacsin. Initial functional annotation of Sacsin was based on sequence homology, with subsequent experiments revealing the Sacsin requirement for regulating mitochondrial dynamics, along with its domains involved in promoting neurofilament assembly or resolving their bundling accumulations. ARSACS phenotypes associated with SACS loss-of-function are discussed, and how advancements in ARSACS disease models and quantitative omics approaches can improve our understanding of ARSACS pathological attributes. Lastly in the perspectives section, we address gene correction strategies for monogenic disorders such as ARSACS, along with their common delivery methods, representing a hopeful area for ARSACS therapeutics development.
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Affiliation(s)
- Khaled A Aly
- Department of Biochemistry, University of Regina, Regina, Saskatchewan, Canada
| | | | - Mara Zilocchi
- Department of Biochemistry, University of Regina, Regina, Saskatchewan, Canada
| | - Sadhna Phanse
- Department of Biochemistry, University of Regina, Regina, Saskatchewan, Canada
| | - Mohan Babu
- Department of Biochemistry, University of Regina, Regina, Saskatchewan, Canada.
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8
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Romano LEL, Aw WY, Hixson KM, Novoselova TV, Havener TM, Howell S, Taylor-Blake B, Hall CL, Xing L, Beri J, Nethisinghe S, Perna L, Hatimy A, Altadonna GC, Graves LM, Herring LE, Hickey AJ, Thalassinos K, Chapple JP, Wolter JM. Multi-omic profiling reveals the ataxia protein sacsin is required for integrin trafficking and synaptic organization. Cell Rep 2022; 41:111580. [PMID: 36323248 PMCID: PMC9647044 DOI: 10.1016/j.celrep.2022.111580] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 06/30/2022] [Accepted: 10/07/2022] [Indexed: 11/06/2022] Open
Abstract
Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a childhood-onset cerebellar ataxia caused by mutations in SACS, which encodes the protein sacsin. Cellular ARSACS phenotypes include mitochondrial dysfunction, intermediate filament disorganization, and progressive death of cerebellar Purkinje neurons. It is unclear why the loss of sacsin causes these deficits or why they manifest as cerebellar ataxia. Here, we perform multi-omic profiling in sacsin knockout (KO) cells and identify alterations in microtubule dynamics and mislocalization of focal adhesion (FA) proteins, including multiple integrins. Deficits in FA structure, signaling, and function can be rescued by targeting PTEN, a negative regulator of FA signaling. ARSACS mice possess mislocalization of ITGA1 in Purkinje neurons and synaptic disorganization in the deep cerebellar nucleus (DCN). The sacsin interactome reveals that sacsin regulates interactions between cytoskeletal and synaptic adhesion proteins. Our findings suggest that disrupted trafficking of synaptic adhesion proteins is a causal molecular deficit in ARSACS.
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Affiliation(s)
- Lisa E L Romano
- Faculty of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, London EC1M 6BQ, UK
| | - Wen Yih Aw
- UNC Catalyst for Rare Diseases, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Kathryn M Hixson
- UNC Catalyst for Rare Diseases, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Tatiana V Novoselova
- Faculty of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, London EC1M 6BQ, UK; Department of Natural Sciences, Faculty of Science and Technology, Middlesex University, London NW4 4BT, UK
| | - Tammy M Havener
- UNC Catalyst for Rare Diseases, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Stefanie Howell
- UNC Catalyst for Rare Diseases, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Bonnie Taylor-Blake
- UNC Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Charlotte L Hall
- Faculty of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, London EC1M 6BQ, UK
| | - Lei Xing
- UNC Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Josh Beri
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; UNC Michael Hooker Proteomics Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Suran Nethisinghe
- Faculty of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, London EC1M 6BQ, UK
| | - Laura Perna
- Faculty of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, London EC1M 6BQ, UK
| | - Abubakar Hatimy
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, UK
| | - Ginevra Chioccioli Altadonna
- Faculty of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, London EC1M 6BQ, UK
| | - Lee M Graves
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, UK; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Laura E Herring
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; UNC Michael Hooker Proteomics Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Anthony J Hickey
- UNC Catalyst for Rare Diseases, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Konstantinos Thalassinos
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, UK; Institute of Structural and Molecular Biology, Birkbeck College, University of London, London WC1E 7HX, UK
| | - J Paul Chapple
- Faculty of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, London EC1M 6BQ, UK.
| | - Justin M Wolter
- UNC Catalyst for Rare Diseases, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; UNC Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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9
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Molecular Characterization of Portuguese Patients with Hereditary Cerebellar Ataxia. Cells 2022; 11:cells11060981. [PMID: 35326432 PMCID: PMC8946949 DOI: 10.3390/cells11060981] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 03/10/2022] [Accepted: 03/11/2022] [Indexed: 01/02/2023] Open
Abstract
Hereditary cerebellar ataxia (HCA) comprises a clinical and genetic heterogeneous group of neurodegenerative disorders characterized by incoordination of movement, speech, and unsteady gait. In this study, we performed whole-exome sequencing (WES) in 19 families with HCA and presumed autosomal recessive (AR) inheritance, to identify the causal genes. A phenotypic classification was performed, considering the main clinical syndromes: spastic ataxia, ataxia and neuropathy, ataxia and oculomotor apraxia (AOA), ataxia and dystonia, and ataxia with cognitive impairment. The most frequent causal genes were associated with spastic ataxia (SACS and KIF1C) and with ataxia and neuropathy or AOA (PNKP). We also identified three families with autosomal dominant (AD) forms arising from de novo variants in KIF1A, CACNA1A, or ATP1A3, reinforcing the importance of differential diagnosis (AR vs. AD forms) in families with only one affected member. Moreover, 10 novel causal-variants were identified, and the detrimental effect of two splice-site variants confirmed through functional assays. Finally, by reviewing the molecular mechanisms, we speculated that regulation of cytoskeleton function might be impaired in spastic ataxia, whereas DNA repair is clearly associated with AOA. In conclusion, our study provided a genetic diagnosis for HCA families and proposed common molecular pathways underlying cerebellar neurodegeneration.
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10
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Toscano Márquez B, Cook AA, Rice M, Smileski A, Vieira-Lomasney K, Charron F, McKinney RA, Watt AJ. Molecular Identity and Location Influence Purkinje Cell Vulnerability in Autosomal-Recessive Spastic Ataxia of Charlevoix-Saguenay Mice. Front Cell Neurosci 2022; 15:707857. [PMID: 34970120 PMCID: PMC8712330 DOI: 10.3389/fncel.2021.707857] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 11/03/2021] [Indexed: 11/13/2022] Open
Abstract
Patterned cell death is a common feature of many neurodegenerative diseases. In patients with autosomal-recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) and mouse models of ARSACS, it has been observed that Purkinje cells in anterior cerebellar vermis are vulnerable to degeneration while those in posterior vermis are resilient. Purkinje cells are known to express certain molecules in a highly stereotyped, patterned manner across the cerebellum. One patterned molecule is zebrin, which is expressed in distinctive stripes across the cerebellar cortex. The different zones delineated by the expression pattern of zebrin and other patterned molecules have been implicated in the patterning of Purkinje cell death, raising the question of whether they contribute to cell death in ARSACS. We found that zebrin patterning appears normal prior to disease onset in Sacs–/– mice, suggesting that zebrin-positive and -negative Purkinje cell zones develop normally. We next observed that zebrin-negative Purkinje cells in anterior lobule III were preferentially susceptible to cell death, while anterior zebrin-positive cells and posterior zebrin-negative and -positive cells remained resilient even at late disease stages. The patterning of Purkinje cell innervation to the target neurons in the cerebellar nuclei (CN) showed a similar pattern of loss: neurons in the anterior CN, where inputs are predominantly zebrin-negative, displayed a loss of Purkinje cell innervation. In contrast, neurons in the posterior CN, which is innervated by both zebrin-negative and -positive puncta, had normal innervation. These results suggest that the location and the molecular identity of Purkinje cells determine their susceptibility to cell death in ARSACS.
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Affiliation(s)
| | - Anna A Cook
- Department of Biology, McGill University, Montreal, QC, Canada
| | - Max Rice
- Department of Biology, McGill University, Montreal, QC, Canada
| | - Alexia Smileski
- Department of Biology, McGill University, Montreal, QC, Canada
| | | | - François Charron
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - R Anne McKinney
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Alanna J Watt
- Department of Biology, McGill University, Montreal, QC, Canada
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11
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Perez H, Abdallah MF, Chavira JI, Norris AS, Egeland MT, Vo KL, Buechsenschuetz CL, Sanghez V, Kim JL, Pind M, Nakamura K, Hicks GG, Gatti RA, Madrenas J, Iacovino M, McKinnon PJ, Mathews PJ. A novel, ataxic mouse model of ataxia telangiectasia caused by a clinically relevant nonsense mutation. eLife 2021; 10:64695. [PMID: 34723800 PMCID: PMC8601662 DOI: 10.7554/elife.64695] [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: 11/07/2020] [Accepted: 10/29/2021] [Indexed: 12/14/2022] Open
Abstract
Ataxia Telangiectasia (A-T) and Ataxia with Ocular Apraxia Type 1 (AOA1) are devastating neurological disorders caused by null mutations in the genome stability genes, A-T mutated (ATM) and Aprataxin (APTX), respectively. Our mechanistic understanding and therapeutic repertoire for treating these disorders are severely lacking, in large part due to the failure of prior animal models with similar null mutations to recapitulate the characteristic loss of motor coordination (i.e., ataxia) and associated cerebellar defects. By increasing genotoxic stress through the insertion of null mutations in both the Atm (nonsense) and Aptx (knockout) genes in the same animal, we have generated a novel mouse model that for the first time develops a progressively severe ataxic phenotype associated with atrophy of the cerebellar molecular layer. We find biophysical properties of cerebellar Purkinje neurons (PNs) are significantly perturbed (e.g., reduced membrane capacitance, lower action potential [AP] thresholds, etc.), while properties of synaptic inputs remain largely unchanged. These perturbations significantly alter PN neural activity, including a progressive reduction in spontaneous AP firing frequency that correlates with both cerebellar atrophy and ataxia over the animal’s first year of life. Double mutant mice also exhibit a high predisposition to developing cancer (thymomas) and immune abnormalities (impaired early thymocyte development and T-cell maturation), symptoms characteristic of A-T. Finally, by inserting a clinically relevant nonsense-type null mutation in Atm, we demonstrate that Small Molecule Read-Through (SMRT) compounds can restore ATM production, indicating their potential as a future A-T therapeutic.
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Affiliation(s)
- Harvey Perez
- The Lundquist Institute for Biomedical Innovation, Harbor-UCLA Medical Center, Torrance, United States
| | - May F Abdallah
- The Lundquist Institute for Biomedical Innovation, Harbor-UCLA Medical Center, Torrance, United States
| | - Jose I Chavira
- The Lundquist Institute for Biomedical Innovation, Harbor-UCLA Medical Center, Torrance, United States
| | - Angelina S Norris
- The Lundquist Institute for Biomedical Innovation, Harbor-UCLA Medical Center, Torrance, United States
| | - Martin T Egeland
- The Lundquist Institute for Biomedical Innovation, Harbor-UCLA Medical Center, Torrance, United States
| | - Karen L Vo
- The Lundquist Institute for Biomedical Innovation, Harbor-UCLA Medical Center, Torrance, United States
| | - Callan L Buechsenschuetz
- The Lundquist Institute for Biomedical Innovation, Harbor-UCLA Medical Center, Torrance, United States
| | - Valentina Sanghez
- The Lundquist Institute for Biomedical Innovation, Harbor-UCLA Medical Center, Torrance, United States
| | - Jeannie L Kim
- The Lundquist Institute for Biomedical Innovation, Harbor-UCLA Medical Center, Torrance, United States
| | - Molly Pind
- Department of Biochemistry and Medical Genetics,Max Rady College of Medicine, University of Manitoba, Manitoba, Canada
| | - Kotoka Nakamura
- Department of Pathology & Laboratory Medicine, David Geffen School of Medicine, Los Angeles, United States
| | - Geoffrey G Hicks
- Department of Biochemistry and Medical Genetics,Max Rady College of Medicine, University of Manitoba, Manitoba, Canada
| | - Richard A Gatti
- Department of Pathology & Laboratory Medicine, David Geffen School of Medicine, Los Angeles, United States
| | - Joaquin Madrenas
- The Lundquist Institute for Biomedical Innovation, Harbor-UCLA Medical Center, Torrance, United States.,Department of Medicine, Harbor-UCLA Medical Center, Torrance, United States
| | - Michelina Iacovino
- The Lundquist Institute for Biomedical Innovation, Harbor-UCLA Medical Center, Torrance, United States.,Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, United States
| | - Peter J McKinnon
- Center for Pediatric Neurological Disease Research, St. Jude Pediatric Translational Neuroscience Initiative, St. Jude Children's Research Hospital, Memphis, United States
| | - Paul J Mathews
- The Lundquist Institute for Biomedical Innovation, Harbor-UCLA Medical Center, Torrance, United States.,Department of Neurology, Harbor-UCLA Medical Center, Torrance, United States
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12
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Longo F, De Ritis D, Miluzio A, Fraticelli D, Baets J, Scarlato M, Santorelli FM, Biffo S, Maltecca F. Assessment of Sacsin Turnover in Patients With ARSACS: Implications for Molecular Diagnosis and Pathogenesis. Neurology 2021; 97:e2315-e2327. [PMID: 34649874 PMCID: PMC8665432 DOI: 10.1212/wnl.0000000000012962] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 10/07/2021] [Indexed: 11/15/2022] Open
Abstract
Background and Objectives Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is caused by variations in SACS gene encoding sacsin, a huge multimodular protein of unknown function. More than 200 SACS variations have been described worldwide to date. Because ARSACS presents phenotypic variability, previous empirical studies attempted to correlate the nature and position of SACS variations with the age at onset or with disease severity, although not considering the effect of the various variations on protein stability. In this work, we studied genotype-phenotype correlation in ARSACS at a functional level. Methods We analyzed a large set of skin fibroblasts derived from patients with ARSACS, including both new and already published cases, carrying variations of different types affecting diverse domains of the protein. Results We found that sacsin is almost absent in patients with ARSACS, regardless of the nature of the variation. As expected, we did not detect sacsin in patients with truncating variations. We found it strikingly reduced or absent also in compound heterozygotes carrying diverse missense variations. In this case, we excluded SACS mRNA decay, defective translation, or faster posttranslational degradation as possible causes of protein reduction. Conversely, our results demonstrate that nascent mutant sacsin protein undergoes cotranslational ubiquitination and degradation. Discussion Our results provide a mechanistic explanation for the lack of genotype-phenotype correlation in ARSACS. We also propose a new and unambiguous criterion for ARSACS diagnosis that is based on the evaluation of sacsin level. Last, we identified preemptive degradation of a mutant protein as a novel cause of a human disease.
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Affiliation(s)
- Fabiana Longo
- Mitochondrial Dysfunctions in Neurodegeneration Unit, Ospedale San Raffaele, Milan, Italy
| | - Daniele De Ritis
- Mitochondrial Dysfunctions in Neurodegeneration Unit, Ospedale San Raffaele, Milan, Italy
| | - Annarita Miluzio
- Istituto Nazionale di Genetica Molecolare, INGM, "Romeo ed Enrica Invernizzi", Milan, Italy
| | - Davide Fraticelli
- Mitochondrial Dysfunctions in Neurodegeneration Unit, Ospedale San Raffaele, Milan, Italy
| | - Jonathan Baets
- Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerpen, Belgium.,Neuromuscular Reference Centre, Department of Neurology, Antwerp University Hospital, Antwerpen, Belgium
| | - Marina Scarlato
- Department of Neurology, Ospedale San Raffaele, Milan, Italy
| | | | - Stefano Biffo
- Istituto Nazionale di Genetica Molecolare, INGM, "Romeo ed Enrica Invernizzi", Milan, Italy.,Department of Biosciences, University of Milan, Milan, Italy
| | - Francesca Maltecca
- Mitochondrial Dysfunctions in Neurodegeneration Unit, Ospedale San Raffaele, Milan, Italy .,Università Vita-Salute San Raffaele, Milan, Italy
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13
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Efficient Neuroprotective Rescue of Sacsin-Related Disease Phenotypes in Zebrafish. Int J Mol Sci 2021; 22:ijms22168401. [PMID: 34445111 PMCID: PMC8395086 DOI: 10.3390/ijms22168401] [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: 06/24/2021] [Revised: 07/24/2021] [Accepted: 07/30/2021] [Indexed: 02/06/2023] Open
Abstract
Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a multisystem hereditary ataxia associated with mutations in SACS, which encodes sacsin, a protein of still only partially understood function. Although mouse models of ARSACS mimic largely the disease progression seen in humans, their use in the validation of effective therapies has not yet been proposed. Recently, the teleost Danio rerio has attracted increasing attention as a vertebrate model that allows rapid and economical screening, of candidate molecules, and thus combines the advantages of whole-organism phenotypic assays and in vitro high-throughput screening assays. Through CRISPR/Cas9-based mutagenesis, we generated and characterized a zebrafish sacs-null mutant line that replicates the main features of ARSACS. The sacs-null fish showed motor impairment, hindbrain atrophy, mitochondrial dysfunction, and reactive oxygen species accumulation. As proof of principle for using these mutant fish in high-throughput screening studies, we showed that both acetyl-DL-leucine and tauroursodeoxycholic acid improved locomotor and biochemical phenotypes in sacs−/− larvae treated with these neuroprotective agents, by mediating significant rescue of the molecular functions altered by sacsin loss. Taken together, the evidence here reported shows the zebrafish to be a valuable model organism for the identification of novel molecular mechanisms and for efficient and rapid in vivo optimization and screening of potential therapeutic compounds. These findings may pave the way for new interventions targeting the earliest phases of Purkinje cell degeneration in ARSACS.
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14
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Subedi B, Anderson S, Croft TL, Rouchka EC, Zhang M, Hammond-Weinberger DR. Gene alteration in zebrafish exposed to a mixture of substances of abuse. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 278:116777. [PMID: 33689951 PMCID: PMC8053679 DOI: 10.1016/j.envpol.2021.116777] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/23/2021] [Accepted: 02/15/2021] [Indexed: 06/12/2023]
Abstract
A recent surge in the use and abuse of diverse prescribed psychotic and illicit drugs necessitates the surveillance of drug residues in source water and the associated ecological impacts of chronic exposure to the aquatic organism. Thirty-six psychotic and illicit drug residues were determined in discharged wastewater from two centralized municipal wastewater treatment facilities and two wastewater receiving creeks for seven consecutive days in Kentucky. Zebrafish (Danio rerio) larvae were exposed to the environmental relevant mixtures of all drug residues, all illicit drugs, and all prescribed psychotic drugs. The extracted RNA from fish homogenates was sequenced, and differentially expressed sequences were analyzed for known or predicted nervous system expression, and screened annotated protein-coding genes to the true environmental cocktail mixture. Illicit stimulant (cocaine and one metabolite), opioids (methadone, methadone metabolite, and oxycodone), hallucinogen (MDA), benzodiazepine (oxazepam and temazepam), carbamazepine, and all target selective serotonin reuptake inhibitors including sertraline, fluoxetine, venlafaxine, and citalopram were quantified in 100% of collected samples from both creeks. The high dose cocktail mixture exposure group revealed the largest group of differentially expressed genes: 100 upregulated and 77 downregulated (p ≤ 0.05; q ≤ 0.05). The top 20 differentially expressed sequences in each exposure group comprise 82 unique transcripts corresponding to 74% annotated genes, 7% non-coding sequences, and 19% uncharacterized sequences. Among 61 differentially expressed sequences that corresponded to annotated protein-coding genes, 23 (38%) genes or their homologs are known to be expressed in the nervous system of fish or other organisms. Several of the differentially expressed sequences are associated primarily with the immune system, including several major histocompatibility complex class I and interferon-induced proteins. Interleukin-1 beta (downregulated in this study) abnormalities are considered a risk factor for psychosis. This is the first study to assess the contributions of multiple classes of psychotic and illicit drugs in combination with developmental gene expression.
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Affiliation(s)
- B Subedi
- Department of Chemistry, Murray State University, Murray, KY, United States.
| | - S Anderson
- Department of Biology, Murray State University, Murray, KY, United States
| | - T L Croft
- Department of Chemistry, Murray State University, Murray, KY, United States
| | - E C Rouchka
- Department of Computer Science and Engineering, University of Louisville, Louisville, KY, United States; KBRIN Bioinformatics Core, University of Louisville, Louisville, KY, United States
| | - M Zhang
- Genomics Facility University of Louisville, Louisville, KY, United States
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15
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Bourcier D, Bélanger M, Côté I, Brais B, Synofzik M, Brisson JD, Rodrigue X, Gagnon MM, Mathieu J, Gagnon C. Documenting the psychometric properties of the scale for the assessment and rating of ataxia to advance trial readiness of Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay. J Neurol Sci 2020; 417:117050. [DOI: 10.1016/j.jns.2020.117050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/13/2020] [Accepted: 07/16/2020] [Indexed: 12/28/2022]
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16
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Lottes EN, Cox DN. Homeostatic Roles of the Proteostasis Network in Dendrites. Front Cell Neurosci 2020; 14:264. [PMID: 33013325 PMCID: PMC7461941 DOI: 10.3389/fncel.2020.00264] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 07/28/2020] [Indexed: 12/13/2022] Open
Abstract
Cellular protein homeostasis, or proteostasis, is indispensable to the survival and function of all cells. Distinct from other cell types, neurons are long-lived, exhibiting architecturally complex and diverse multipolar projection morphologies that can span great distances. These properties present unique demands on proteostatic machinery to dynamically regulate the neuronal proteome in both space and time. Proteostasis is regulated by a distributed network of cellular processes, the proteostasis network (PN), which ensures precise control of protein synthesis, native conformational folding and maintenance, and protein turnover and degradation, collectively safeguarding proteome integrity both under homeostatic conditions and in the contexts of cellular stress, aging, and disease. Dendrites are equipped with distributed cellular machinery for protein synthesis and turnover, including dendritically trafficked ribosomes, chaperones, and autophagosomes. The PN can be subdivided into an adaptive network of three major functional pathways that synergistically govern protein quality control through the action of (1) protein synthesis machinery; (2) maintenance mechanisms including molecular chaperones involved in protein folding; and (3) degradative pathways (e.g., Ubiquitin-Proteasome System (UPS), endolysosomal pathway, and autophagy. Perturbations in any of the three arms of proteostasis can have dramatic effects on neurons, especially on their dendrites, which require tightly controlled homeostasis for proper development and maintenance. Moreover, the critical importance of the PN as a cell surveillance system against protein dyshomeostasis has been highlighted by extensive work demonstrating that the aggregation and/or failure to clear aggregated proteins figures centrally in many neurological disorders. While these studies demonstrate the relevance of derangements in proteostasis to human neurological disease, here we mainly review recent literature on homeostatic developmental roles the PN machinery plays in the establishment, maintenance, and plasticity of stable and dynamic dendritic arbors. Beyond basic housekeeping functions, we consider roles of PN machinery in protein quality control mechanisms linked to dendritic plasticity (e.g., dendritic spine remodeling during LTP); cell-type specificity; dendritic morphogenesis; and dendritic pruning.
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Affiliation(s)
- Erin N Lottes
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Daniel N Cox
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
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17
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Cook AA, Fields E, Watt AJ. Losing the Beat: Contribution of Purkinje Cell Firing Dysfunction to Disease, and Its Reversal. Neuroscience 2020; 462:247-261. [PMID: 32554108 DOI: 10.1016/j.neuroscience.2020.06.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/01/2020] [Accepted: 06/05/2020] [Indexed: 02/06/2023]
Abstract
The cerebellum is a brain structure that is highly interconnected with other brain regions. There are many contributing factors to cerebellar-related brain disease, such as altered afferent input, local connectivity, and/or cerebellar output. Purkinje cells (PC) are the principle cells of the cerebellar cortex, and fire intrinsically; that is, they fire spontaneous action potentials at high frequencies. This review paper focuses on PC intrinsic firing activity, which is altered in multiple neurological diseases, including ataxia, Huntington Disease (HD) and autism spectrum disorder (ASD). Notably, there are several cases where interventions that restore or rescue PC intrinsic activity also improve impaired behavior in these mouse models of disease. These findings suggest that rescuing PC firing deficits themselves may be sufficient to improve impairment in cerebellar-related behavior in disease. We propose that restoring PC intrinsic firing represents a good target for drug development that might be of therapeutic use for several disorders.
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Affiliation(s)
- Anna A Cook
- Department of Biology, McGill University, Montreal, Canada
| | - Eviatar Fields
- Department of Biology, McGill University, Montreal, Canada; Integrated Program in Neuroscience, McGill University, Montreal, Canada
| | - Alanna J Watt
- Department of Biology, McGill University, Montreal, Canada.
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18
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Rudenskaya GE, Kadnikova VA, Ryzhkova OP. [Spastic ataxia of Charlevoix-Saguenay: the first Russian case report and literature review]. Zh Nevrol Psikhiatr Im S S Korsakova 2020; 120:85-91. [PMID: 32307416 DOI: 10.17116/jnevro202012002185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Spastic ataxia of Charlevoix-Saguenay (ARSACS) is a rare autosomal recessive neurodegenerative disease related to SACS gene and characterized by cerebellar, pyramidal and some other signs. The disease was delineated in Quebec, where it cumulates due to founder effect and has similar phenotype with very early onset. ARSACS in other populations is more variable. The first Russian case of ARSACS in a 37-year-old woman, an only patient in a Lak (one of Dagestan ethnicities) family, is presented. Along with main typical features, she had atypical late disease onset (in 32 years) and moderate cognitive decline. MPS-panel 'hereditary paraplegias' detected an earlier reported homo- or hemizygous mutation c.72276C>T (p.Arg2426Stop) in SACS exon 10.
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Affiliation(s)
| | - V A Kadnikova
- Research Centre for Medical Genetics, Moscow, Russia
| | - O P Ryzhkova
- Research Centre for Medical Genetics, Moscow, Russia
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19
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Pensabene MC, Melis M, Corato LD, Stefano CD, Pizzicannella G, Mondillo M, Amico A, Tatulli D, Floris R. Autosomal recessive spastic ataxia of charlevoix-saguenay: Findings from MRI in two adult Italian siblings. Radiol Case Rep 2020; 15:507-510. [PMID: 32140197 PMCID: PMC7044677 DOI: 10.1016/j.radcr.2019.12.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 12/23/2019] [Accepted: 12/28/2019] [Indexed: 11/25/2022] Open
Abstract
Autosomal recessive spastic ataxia of Charlevoix-Saguenay is a rare neurodegenerative disorder caused by homozygous mutations in SACSgene. We present finding on MR imaging in 2 adult Italian siblings. According to the literature we have described same of typical MRI finding of autosomal recessive spastic ataxia of Charlevoix-Saguenay disease. We found slight differences in neuroimaging pattern in our patients with a similar genotype but different age and clinical severity, this suggest that brain MRI may provide potential biomarkers to assess disease progression.
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Affiliation(s)
- Maria Claudia Pensabene
- University of Rome Tor Vergata, Department of Experimental Medicine and Surgery, Rome, Italy
| | - Milena Melis
- University of Rome Tor Vergata, Department of Experimental Medicine and Surgery, Rome, Italy
| | - Laura De Corato
- University of Rome Tor Vergata, Department of Experimental Medicine and Surgery, Rome, Italy
| | - Carla Di Stefano
- University of Rome Tor Vergata, Department of Experimental Medicine and Surgery, Rome, Italy
| | - Giulia Pizzicannella
- University of Rome Tor Vergata, Department of Experimental Medicine and Surgery, Rome, Italy
| | - Mariateresa Mondillo
- University of Rome Tor Vergata, Department of Experimental Medicine and Surgery, Rome, Italy
| | - Andrea Amico
- University of Rome Tor Vergata, Department of Experimental Medicine and Surgery, Rome, Italy
| | - Doriana Tatulli
- University of Rome Tor Vergata, Department of Experimental Medicine and Surgery, Rome, Italy
| | - Roberto Floris
- University of Rome Tor Vergata, Department of Experimental Medicine and Surgery, Rome, Italy
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20
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Xiromerisiou G, Dadouli K, Marogianni C, Provatas A, Ntellas P, Rikos D, Stathis P, Georgouli D, Loules G, Zamanakou M, Hadjigeorgiou GM. A novel homozygous SACS mutation identified by whole exome sequencing-genotype phenotype correlations of all published cases. J Mol Neurosci 2019; 70:131-141. [PMID: 31701440 DOI: 10.1007/s12031-019-01410-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 09/26/2019] [Indexed: 02/07/2023]
Abstract
ARSACS is an autosomal recessive disorder characterized by ataxia, spasticity, and polyneuropathy. A plethora of worldwide distributed mutations have been described so far. Here, we report two brothers, born to non-consanguineous parents, presenting with cerebellar ataxia and peripheral neuropathy. Whole-exome sequencing revealed the presence of a novel homozygous variant in the SACS gene. The variant was confirmed by Sanger sequencing and found at heterozygous state in both parents. This is the first reported mutation in this gene, in Greek population. This case report further highlights the growing trend of identifying genetic diseases previously restricted to single, ethnically isolated regions in many different ethnic groups worldwide. Additionally, we performed a systematic review of all published cases with SACs mutations. ARSACS seems to be an important cause of ataxia and many different types of mutations have been identified, mainly located in exon 10. We evaluated the mutation pathogenicity in all previously reported cases to investigate possible phenotype-genotype correlations. We managed to find a correlation between the pathogenicity of mutations, severity of the phenotype, and age of onset of ARSACS. Greater mutation numbers in different populations will be important and mutation-specific functional studies will be essential to identify the pathogenicity of the various ARSACS variants.
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Affiliation(s)
- Georgia Xiromerisiou
- Department of Neurology, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece.
| | - Katerina Dadouli
- Department of Hygiene and Epidemiology, Faculty of Medicine, University of Thessaly, Larissa, Greece
| | - Chrysoula Marogianni
- Department of Neurology, University of Thessaly, University Hospital of Larissa, Larissa, Greece
| | - Antonios Provatas
- Department of Neurology, University of Thessaly, University Hospital of Larissa, Larissa, Greece
| | - Panagiotis Ntellas
- Department of Medical Oncology, University Hospital of Ioannina, Ioannina, Greece
| | - Dimitrios Rikos
- Department of Neurology, University of Thessaly, University Hospital of Larissa, Larissa, Greece
| | - Pantelis Stathis
- Department of Neurology, Mediterraneo Hospital, Glyfada, Athens, Greece
| | - Despina Georgouli
- Department of Neurology, University of Thessaly, University Hospital of Larissa, Larissa, Greece
| | | | | | - Georgios M Hadjigeorgiou
- Department of Neurology, Laboratory of Neurogenetics, University of Thessaly, University Hospital of Larissa, Larissa, Greece.,Department of Neurology, Medical School, University of Cyprus, Nicosia, Cyprus
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