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Bennett CL, Dastidar S, Arnold FJ, McKinstry SU, Stockford C, Freibaum BD, Sopher BL, Wu M, Seidner G, Joiner W, Taylor JP, West RJH, La Spada AR. Senataxin helicase, the causal gene defect in ALS4, is a significant modifier of C9orf72 ALS G4C2 and arginine-containing dipeptide repeat toxicity. Acta Neuropathol Commun 2023; 11:164. [PMID: 37845749 PMCID: PMC10580588 DOI: 10.1186/s40478-023-01665-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 10/04/2023] [Indexed: 10/18/2023] Open
Abstract
Identifying genetic modifiers of familial amyotrophic lateral sclerosis (ALS) may reveal targets for therapeutic modulation with potential application to sporadic ALS. GGGGCC (G4C2) repeat expansions in the C9orf72 gene underlie the most common form of familial ALS, and generate toxic arginine-containing dipeptide repeats (DPRs), which interfere with membraneless organelles, such as the nucleolus. Here we considered senataxin (SETX), the genetic cause of ALS4, as a modifier of C9orf72 ALS, because SETX is a nuclear helicase that may regulate RNA-protein interactions involved in ALS dysfunction. After documenting that decreased SETX expression enhances arginine-containing DPR toxicity and C9orf72 repeat expansion toxicity in HEK293 cells and primary neurons, we generated SETX fly lines and evaluated the effect of SETX in flies expressing either (G4C2)58 repeats or glycine-arginine-50 [GR(50)] DPRs. We observed dramatic suppression of disease phenotypes in (G4C2)58 and GR(50) Drosophila models, and detected a striking relocalization of GR(50) out of the nucleolus in flies co-expressing SETX. Next-generation GR(1000) fly models, that show age-related motor deficits in climbing and movement assays, were similarly rescued with SETX co-expression. We noted that the physical interaction between SETX and arginine-containing DPRs is partially RNA-dependent. Finally, we directly assessed the nucleolus in cells expressing GR-DPRs, confirmed reduced mobility of proteins trafficking to the nucleolus upon GR-DPR expression, and found that SETX dosage modulated nucleolus liquidity in GR-DPR-expressing cells and motor neurons. These findings reveal a hitherto unknown connection between SETX function and cellular processes contributing to neuron demise in the most common form of familial ALS.
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Affiliation(s)
- Craig L Bennett
- Departments of Pathology, Laboratory Medicine, Neurology, and Biological Chemistry, UCI Center for Neurotherapeutics, University of California Irvine School of Medicine, Irvine, CA, 92697, USA
- Department of Neurology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Somasish Dastidar
- Department of Neurology, Duke University School of Medicine, Durham, NC, 27710, USA
- Center for Molecular Neurosciences, Kasturba Medical College, Manipal, 576104, India
| | - Frederick J Arnold
- Departments of Pathology, Laboratory Medicine, Neurology, and Biological Chemistry, UCI Center for Neurotherapeutics, University of California Irvine School of Medicine, Irvine, CA, 92697, USA
| | - Spencer U McKinstry
- Department of Neurology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Cameron Stockford
- Departments of Pathology, Laboratory Medicine, Neurology, and Biological Chemistry, UCI Center for Neurotherapeutics, University of California Irvine School of Medicine, Irvine, CA, 92697, USA
| | - Brian D Freibaum
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Bryce L Sopher
- Department of Laboratory Medicine and Pathology, University of Washington Medical Center, Seattle, WA, 98195, USA
| | - Meilin Wu
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Glen Seidner
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - William Joiner
- Department of Laboratory Medicine and Pathology, University of Washington Medical Center, Seattle, WA, 98195, USA
| | - J Paul Taylor
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, 20815, USA
| | - Ryan J H West
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, S10 2HQ, UK.
- Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK.
| | - Albert R La Spada
- Departments of Pathology, Laboratory Medicine, Neurology, and Biological Chemistry, UCI Center for Neurotherapeutics, University of California Irvine School of Medicine, Irvine, CA, 92697, USA.
- Department of Neurology, Duke University School of Medicine, Durham, NC, 27710, USA.
- Department of Neurobiology and Behavior, University of California Irvine School of Biosciences, Irvine, CA, 92697, USA.
- UCI Center for Neurotherapeutics, University of California Irvine, Irvine, CA, 92697, USA.
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Sharpe JL, Harper NS, West RJH. Identification and Monitoring of Nucleotide Repeat Expansions Using Southern Blotting in Drosophila Models of C9orf72 Motor Neuron Disease and Frontotemporal Dementia. Bio Protoc 2022; 12:e4424. [PMID: 35813024 PMCID: PMC9183971 DOI: 10.21769/bioprotoc.4424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 12/29/2022] Open
Abstract
Repeat expansion diseases, including fragile X syndrome, Huntington's disease, and C9orf72-related motor neuron disease and frontotemporal dementia, are a group of disorders associated with polymorphic expansions of tandem repeat nucleotide sequences. These expansions are highly repetitive and often hundreds to thousands of repeats in length, making accurate identification and determination of repeat length via PCR or sequencing challenging. Here we describe a protocol for monitoring repeat length in Drosophila models carrying 1,000 repeat C9orf72-related dipeptide repeat transgenes using Southern blotting. This protocol has been used regularly to check the length of these lines for over 100 generations with robust and repeatable results and can be implemented for monitoring any repeat expansion in Drosophila.
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Affiliation(s)
- Joanne L. Sharpe
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
,Sheffield Institute for Translational Neuroscience, The University of Sheffield, Sheffield, United Kingdom
,Neuroscience Institute, The University of Sheffield, Sheffield, United Kingdom
| | - Nikki S. Harper
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Ryan J. H. West
- Sheffield Institute for Translational Neuroscience, The University of Sheffield, Sheffield, United Kingdom
,Neuroscience Institute, The University of Sheffield, Sheffield, United Kingdom
,
*For correspondence:
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Sharpe JL, Harper NS, Garner DR, West RJH. Modeling C9orf72-Related Frontotemporal Dementia and Amyotrophic Lateral Sclerosis in Drosophila. Front Cell Neurosci 2021; 15:770937. [PMID: 34744635 PMCID: PMC8566814 DOI: 10.3389/fncel.2021.770937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 09/27/2021] [Indexed: 12/28/2022] Open
Abstract
An intronic hexanucleotide (GGGGCC) expansion in the C9orf72 gene is the most common genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). In the decade following its discovery, much progress has been made in enhancing our understanding of how it precipitates disease. Both loss of function caused by reduced C9orf72 transcript levels, and gain of function mechanisms, triggered by the production of repetitive sense and antisense RNA and dipeptide repeat proteins, are thought to contribute to the toxicity. Drosophila models, with their unrivaled genetic tractability and short lifespan, have played a key role in developing our understanding of C9orf72-related FTD/ALS. There is no C9orf72 homolog in fly, and although this precludes investigations into loss of function toxicity, it is useful for elucidating mechanisms underpinning gain of function toxicity. To date there are a range of Drosophila C9orf72 models, encompassing different aspects of gain of function toxicity. In addition to pure repeat transgenes, which produce both repeat RNA and dipeptide repeat proteins (DPRs), RNA only models and DPR models have been generated to unpick the individual contributions of RNA and each dipeptide repeat protein to C9orf72 toxicity. In this review, we discuss how Drosophila models have shaped our understanding of C9orf72 gain of function toxicity, and address opportunities to utilize these models for further research.
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Affiliation(s)
- Joanne L Sharpe
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Nikki S Harper
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Duncan R Garner
- Sheffield Institute for Translational Neuroscience, The University of Sheffield, Sheffield, United Kingdom.,Neuroscience Institute, The University of Sheffield, Sheffield, United Kingdom
| | - Ryan J H West
- Sheffield Institute for Translational Neuroscience, The University of Sheffield, Sheffield, United Kingdom.,Neuroscience Institute, The University of Sheffield, Sheffield, United Kingdom
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West RJH, Ugbode C, Fort-Aznar L, Sweeney ST. Neuroprotective activity of ursodeoxycholic acid in CHMP2B Intron5 models of frontotemporal dementia. Neurobiol Dis 2020; 144:105047. [PMID: 32801000 PMCID: PMC7491204 DOI: 10.1016/j.nbd.2020.105047] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/16/2020] [Accepted: 08/08/2020] [Indexed: 12/12/2022] Open
Abstract
Frontotemporal dementia (FTD) is one of the most prevalent forms of early-onset dementia. It represents part of the FTD-Amyotrophic Lateral Sclerosis (ALS) spectrum, a continuum of genetically and pathologically overlapping disorders. FTD-causing mutations in CHMP2B, a gene encoding a core component of the heteromeric ESCRT-III Complex, lead to perturbed endosomal-lysosomal and autophagic trafficking with impaired proteostasis. While CHMP2B mutations are rare, dysfunctional endosomal-lysosomal signalling is common across the FTD-ALS spectrum. Using our established Drosophila and mammalian models of CHMP2BIntron5 induced FTD we demonstrate that the FDA-approved compound Ursodeoxycholic Acid (UDCA) conveys neuroprotection, downstream of endosomal-lysosomal dysfunction in both Drosophila and primary mammalian neurons. UDCA exhibited a dose dependent rescue of neuronal structure and function in Drosophila pan-neuronally expressing CHMP2BIntron5. Rescue of CHMP2BIntron5 dependent dendritic collapse and apoptosis with UDCA in rat primary neurons was also observed. UDCA failed to ameliorate aberrant accumulation of endosomal and autophagic organelles or ubiquitinated neuronal inclusions in both models. We demonstrate the neuroprotective activity of UDCA downstream of endosomal-lysosomal and autophagic dysfunction, delineating the molecular mode of action of UDCA and highlighting its potential as a therapeutic for the treatment of FTD-ALS spectrum disorders.
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Affiliation(s)
- Ryan J H West
- Sheffield Institute for Translational Neuroscience, University of Sheffield, S10 2HQ, UK; Neuroscience Institute, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Chris Ugbode
- Department of Biology, University of York, York YO10 5DD, UK
| | | | - Sean T Sweeney
- Department of Biology, University of York, York YO10 5DD, UK.
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West RJH, Sharpe JL, Voelzmann A, Munro AL, Hahn I, Baines RA, Pickering-Brown S. Co-expression of C9orf72 related dipeptide-repeats over 1000 repeat units reveals age- and combination-specific phenotypic profiles in Drosophila. Acta Neuropathol Commun 2020; 8:158. [PMID: 32894207 PMCID: PMC7487709 DOI: 10.1186/s40478-020-01028-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 08/19/2020] [Indexed: 02/08/2023] Open
Abstract
A large intronic hexanucleotide repeat expansion (GGGGCC) within the C9orf72 (C9orf72-SMCR8 Complex Subunit) locus is the most prevalent genetic cause of both Frontotemporal Dementia (FTD) and Motor Neuron Disease (MND). In patients this expansion is typically hundreds to thousands of repeat units in length. Repeat associated non-AUG translation of the expansion leads to the formation of toxic, pathological Dipeptide-Repeat Proteins (DPRs). To date there remains a lack of in vivo models expressing C9orf72 related DPRs with a repeat length of more than a few hundred repeats. As such our understanding of how physiologically relevant repeat length DPRs effect the nervous system in an ageing in vivo system remains limited. In this study we generated Drosophila models expressing DPRs over 1000 repeat units in length, a known pathological length in humans. Using these models, we demonstrate each DPR exhibits a unique, age-dependent, phenotypic and pathological profile. Furthermore, we show co-expression of specific DPR combinations leads to distinct, age-dependent, phenotypes not observed through expression of single DPRs. We propose these models represent a unique, in vivo, tool for dissecting the molecular mechanisms implicated in disease pathology, opening up new avenues in the study of both MND and FTD.
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Affiliation(s)
- Ryan J. H. West
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield, S10 2HQ UK
- Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN UK
| | - Joanne L. Sharpe
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - André Voelzmann
- Division of Molecular and Cellular Function, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Anna L. Munro
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Ines Hahn
- Division of Molecular and Cellular Function, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Richard A. Baines
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Stuart Pickering-Brown
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
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Abstract
There is increasing evidence for a strong genetic basis for autism, with many genetic models being developed in an attempt to replicate autistic symptoms in animals. However, current animal behaviour paradigms rarely match the social and cognitive behaviours exhibited by autistic individuals. Here, we instead assay another functional domain—sensory processing—known to be affected in autism to test a novel genetic autism model in Drosophila melanogaster. We show similar visual response alterations and a similar development trajectory in Nhe3 mutant flies (total n = 72) and in autistic human participants (total n = 154). We report a dissociation between first- and second-order electrophysiological visual responses to steady-state stimulation in adult mutant fruit flies that is strikingly similar to the response pattern in human adults with ASD as well as that of a large sample of neurotypical individuals with high numbers of autistic traits. We explain this as a genetically driven, selective signalling alteration in transient visual dynamics. In contrast to adults, autistic children show a decrease in the first-order response that is matched by the fruit fly model, suggesting that a compensatory change in processing occurs during development. Our results provide the first animal model of autism comprising a differential developmental phenotype in visual processing.
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Affiliation(s)
- Greta Vilidaite
- 1 Department of Psychology, Stanford University , Stanford, CA 94305 , USA
| | - Anthony M Norcia
- 1 Department of Psychology, Stanford University , Stanford, CA 94305 , USA
| | - Ryan J H West
- 3 Department of Biology, University of York , York YO10 5DD , UK
| | | | - Francesca Pei
- 2 Department of Psychiatry, Stanford University , Stanford, CA 94305 , USA
| | - Alex R Wade
- 3 Department of Biology, University of York , York YO10 5DD , UK.,4 Department of Psychology, University of York , York YO10 5DD , UK
| | - Daniel H Baker
- 4 Department of Psychology, University of York , York YO10 5DD , UK
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7
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West RJH, Ugbode C, Gao FB, Sweeney ST. The pro-apoptotic JNK scaffold POSH/SH3RF1 mediates CHMP2BIntron5-associated toxicity in animal models of frontotemporal dementia. Hum Mol Genet 2019; 27:1382-1395. [PMID: 29432529 PMCID: PMC6454437 DOI: 10.1093/hmg/ddy048] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 02/05/2018] [Indexed: 01/01/2023] Open
Abstract
Frontotemporal dementia (FTD) is one of the most prevalent forms of early-onset dementia. However, the pathological mechanisms driving neuronal atrophy in FTD remain poorly understood. Here we identify a conserved role for the novel pro-apoptotic protein plenty of SH3s (POSH)/SH3 domain containing ring finger 1 in mediating neuropathology in Drosophila and mammalian models of charged multivesicular body protein 2B (CHMP2BIntron5) associated FTD. Aberrant, AKT dependent, accumulation of POSH was observed throughout the nervous system of both Drosophila and mice expressing CHMP2BIntron5. Knockdown of POSH was shown to be neuroprotective and sufficient to alleviate aberrant neuronal morphology, behavioral deficits and premature-lethality in Drosophila models, as well as dendritic collapse and cell death in CHMP2BIntron5expressing rat primary neurons. POSH knockdown also ameliorated elevated markers of Jun N-terminal kinase and apoptotic cascades in both Drosophila and mammalian models. This study provides the first characterization of POSH as a potential component of an FTD neuropathology, identifying a novel apoptotic pathway with relevance to the FTD spectrum.
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Affiliation(s)
- Ryan J H West
- Department of Biology, University of York, York YO10 5DD, UK
| | - Chris Ugbode
- Department of Biology, University of York, York YO10 5DD, UK
| | - Fen-Biao Gao
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Sean T Sweeney
- Department of Biology, University of York, York YO10 5DD, UK
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West RJH, Briggs L, Perona Fjeldstad M, Ribchester RR, Sweeney ST. Sphingolipids regulate neuromuscular synapse structure and function in Drosophila. J Comp Neurol 2018; 526:1995-2009. [PMID: 29761896 PMCID: PMC6175220 DOI: 10.1002/cne.24466] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 04/10/2018] [Accepted: 04/10/2018] [Indexed: 12/27/2022]
Abstract
Sphingolipids are found in abundance at synapses and have been implicated in regulation of synapse structure, function, and degeneration. Their precise role in these processes, however, remains obscure. Serine Palmitoyl-transferase (SPT) is the first enzymatic step for synthesis of sphingolipids. Analysis of the Drosophila larval neuromuscular junction (NMJ) revealed mutations in the SPT enzyme subunit, lace/SPTLC2 resulted in deficits in synaptic structure and function. Although NMJ length is normal in lace mutants, the number of boutons per NMJ is reduced to ∼50% of the wild type number. Synaptic boutons in lace mutants are much larger but show little perturbation to the general ultrastructure. Electrophysiological analysis of lace mutant synapses revealed strong synaptic transmission coupled with predominance of depression over facilitation. The structural and functional phenotypes of lace mirrored aspects of Basigin (Bsg), a small Ig-domain adhesion molecule also known to regulate synaptic structure and function. Mutant combinations of lace and Bsg generated large synaptic boutons, while lace mutants showed abnormal accumulation of Bsg at synapses, suggesting that Bsg requires sphingolipid to regulate structure of the synapse. In support of this, we found Bsg to be enriched in lipid rafts. Our data points to a role for sphingolipids in the regulation and fine-tuning of synaptic structure and function while sphingolipid regulation of synaptic structure may be mediated via the activity of Bsg.
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Affiliation(s)
- Ryan J. H. West
- Department of Biology and Hull York Medical SchoolUniversity of YorkHeslingtonYork YO10 5DDUK
| | - Laura Briggs
- Department of Biology and Hull York Medical SchoolUniversity of YorkHeslingtonYork YO10 5DDUK
| | - Maria Perona Fjeldstad
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Discovery Brain SciencesUniversity of EdinburghEdinburgh EH8 9JZUK
| | - Richard R. Ribchester
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Discovery Brain SciencesUniversity of EdinburghEdinburgh EH8 9JZUK
| | - Sean T. Sweeney
- Department of Biology and Hull York Medical SchoolUniversity of YorkHeslingtonYork YO10 5DDUK
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Himmelberg MM, West RJH, Elliott CJH, Wade AR. Abnormal visual gain control and excitotoxicity in early-onset Parkinson's disease Drosophila models. J Neurophysiol 2018; 119:957-970. [PMID: 29142100 PMCID: PMC5899316 DOI: 10.1152/jn.00681.2017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 11/13/2017] [Accepted: 11/13/2017] [Indexed: 12/17/2022] Open
Abstract
The excitotoxic theory of Parkinson's disease (PD) hypothesizes that a pathophysiological degeneration of dopaminergic neurons stems from neural hyperactivity at early stages of disease, leading to mitochondrial stress and cell death. Recent research has harnessed the visual system of Drosophila PD models to probe this hypothesis. Here, we investigate whether abnormal visual sensitivity and excitotoxicity occur in early-onset PD (EOPD) Drosophila models DJ-1αΔ72, DJ-1βΔ 93, and PINK15. We used an electroretinogram to record steady-state visually evoked potentials driven by temporal contrast stimuli. At 1 day of age, all EOPD mutants had a twofold increase in response amplitudes compared with w̄ controls. Furthermore, we found that excitotoxicity occurs in older EOPD models after increased neural activity is triggered by visual stimulation. In an additional analysis, we used a linear discriminant analysis to test whether there were subtle variations in neural gain control that could be used to classify Drosophila into their correct age and genotype. The discriminant analysis was highly accurate, classifying Drosophila into their correct genotypic class at all age groups at 50-70% accuracy (20% chance baseline). Differences in cellular processes link to subtle alterations in neural network operation in young flies, all of which lead to the same pathogenic outcome. Our data are the first to quantify abnormal gain control and excitotoxicity in EOPD Drosophila mutants. We conclude that EOPD mutations may be linked to more sensitive neuronal signaling in prodromal animals that may cause the expression of PD symptomologies later in life. NEW & NOTEWORTHY Steady-state visually evoked potential response amplitudes to multivariate temporal contrast stimuli were recorded in early-onset PD Drosophila models. Our data indicate that abnormal gain control and a subsequent visual loss occur in these PD mutants, supporting a broader excitotoxicity hypothesis in genetic PD. Furthermore, linear discriminant analysis could accurately classify Drosophila into their correct genotype at different ages throughout their lifespan. Our results suggest increased neural signaling in prodromal PD patients.
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Affiliation(s)
- Marc M Himmelberg
- Department of Psychology, The University of York , York , United Kingdom
| | - Ryan J H West
- Department of Biology, The University of York , York , United Kingdom
| | | | - Alex R Wade
- Department of Psychology, The University of York , York , United Kingdom
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Himmelberg MM, West RJH, Wade AR, Elliott CJH. A perceptive plus in Parkinson's disease. Mov Disord 2018; 33:248. [PMID: 29333617 PMCID: PMC5838541 DOI: 10.1002/mds.27240] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 10/09/2017] [Accepted: 10/16/2017] [Indexed: 11/08/2022] Open
Affiliation(s)
| | - Ryan J H West
- Department of Biology, The University of York, York, UK
| | - Alex R Wade
- Department of Psychology, The University of York, York, UK
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West RJH, Elliott CJH, Wade AR. Classification of Parkinson's Disease Genotypes in Drosophila Using Spatiotemporal Profiling of Vision. Sci Rep 2015; 5:16933. [PMID: 26597171 PMCID: PMC4657034 DOI: 10.1038/srep16933] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 10/19/2015] [Indexed: 12/13/2022] Open
Abstract
Electrophysiological studies indicate altered contrast processing in some Parkinson's Disease (PD) patients. We recently demonstrated that vision is altered in Drosophila PD models and hypothesised that different types of genetic and idiopathic PD may affect dopaminergic visual signalling pathways differently. Here we asked whether visual responses in Drosophila could be used to identify PD mutations. To mimic a clinical setting a range of flies was used. Young flies from four control lines were compared to three early-onset PD mutations (PINK1, DJ-1α and DJ-1β), and to two other neurodegenerative mutations, one in the fly LRRK2 orthologue (dLRRK) the other in eggroll, a model of general neurodegeneration in Drosophila. Stimuli were contrast reversing gratings spanning 64 spatiotemporal frequency combinations. We recorded the steady-state visually-evoked response amplitude across all combinations. We found that the pattern of neuronal responses differed between genotypes. Wild-type and early-onset PD flies formed separate clusters; the late-onset mutation is an outlier. Neuronal responses in early-onset PD flies were stronger than in wild-types. Multivariate pattern analysis grouped flies by PD/non-PD genotype with an accuracy >85%. We propose that machine learning algorithms may be useful in increasing the diagnostic specificity of human electrophysiological measurements in both animal models and PD patients.
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Affiliation(s)
- Ryan J H West
- Department of Biology, The University of York, York.,Department of Psychology, The University of York, York
| | | | - Alex R Wade
- Department of Psychology, The University of York, York
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Oswald MCW, West RJH, Lloyd-Evans E, Sweeney ST. Identification of dietary alanine toxicity and trafficking dysfunction in a Drosophila model of hereditary sensory and autonomic neuropathy type 1. Hum Mol Genet 2015; 24:6899-909. [PMID: 26395456 PMCID: PMC4654049 DOI: 10.1093/hmg/ddv390] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 09/15/2015] [Indexed: 01/27/2023] Open
Abstract
Hereditary sensory and autonomic neuropathy type 1 (HSAN1) is characterized by a loss of distal peripheral sensory and motorneuronal function, neuropathic pain and tissue necrosis. The most common cause of HSAN1 is due to dominant mutations in serine palmitoyl-transferase subunit 1 (SPT1). SPT catalyses the condensation of serine with palmitoyl-CoA, the initial step in sphingolipid biogenesis. Identified mutations in SPT1 are known to both reduce sphingolipid synthesis and generate catalytic promiscuity, incorporating alanine or glycine into the precursor sphingolipid to generate a deoxysphingoid base (DSB). Why either loss of function in SPT1, or generation of DSBs should generate deficits in distal sensory function remains unclear. To address these questions, we generated a Drosophila model of HSAN1. Expression of dSpt1 bearing a disease-related mutation induced morphological deficits in synapse growth at the larval neuromuscular junction consistent with a dominant-negative action. Expression of mutant dSpt1 globally was found to be mildly toxic, but was completely toxic when the diet was supplemented with alanine, when DSBs were observed in abundance. Expression of mutant dSpt1 in sensory neurons generated developmental deficits in dendritic arborization with concomitant sensory deficits. A membrane trafficking defect was observed in soma of sensory neurons expressing mutant dSpt1, consistent with endoplasmic reticulum (ER) to Golgi block. We found that we could rescue sensory function in neurons expressing mutant dSpt1 by co-expressing an effector of ER-Golgi function, Rab1 suggesting compromised ER function in HSAN1 affected dendritic neurons. Our Drosophila model identifies a novel strategy to explore the pathological mechanisms of HSAN1.
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Affiliation(s)
- Matthew C W Oswald
- Department of Biology and Hull-York Medical School, University of York, York YO10 5DD, UK and
| | - Ryan J H West
- Department of Biology and Hull-York Medical School, University of York, York YO10 5DD, UK and
| | - Emyr Lloyd-Evans
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK
| | - Sean T Sweeney
- Department of Biology and Hull-York Medical School, University of York, York YO10 5DD, UK and
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Katzemich A, West RJH, Fukuzawa A, Sweeney ST, Gautel M, Sparrow J, Bullard B. Binding partners of the kinase domains in Drosophila obscurin and their effect on the structure of the flight muscle. J Cell Sci 2015; 128:3386-97. [PMID: 26251439 DOI: 10.1242/jcs.170639] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 07/27/2015] [Indexed: 01/15/2023] Open
Abstract
Drosophila obscurin (Unc-89) is a titin-like protein in the M-line of the muscle sarcomere. Obscurin has two kinase domains near the C-terminus, both of which are predicted to be inactive. We have identified proteins binding to the kinase domains. Kinase domain 1 bound Bällchen (Ball, an active kinase), and both kinase domains 1 and 2 bound MASK (a 400-kDa protein with ankyrin repeats). Ball was present in the Z-disc and M-line of the indirect flight muscle (IFM) and was diffusely distributed in the sarcomere. MASK was present in both the M-line and the Z-disc. Reducing expression of Ball or MASK by siRNA resulted in abnormalities in the IFM, including missing M-lines and multiple Z-discs. Obscurin was still present, suggesting that the kinase domains act as a scaffold binding Ball and MASK. Unlike obscurin in vertebrate skeletal muscle, Drosophila obscurin is necessary for the correct assembly of the IFM sarcomere. We show that Ball and MASK act downstream of obscurin, and both are needed for development of a well defined M-line and Z-disc. The proteins have not previously been identified in Drosophila muscle.
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Affiliation(s)
- Anja Katzemich
- Department of Biology, University of York, York YO10 5DD, UK
| | - Ryan J H West
- Department of Biology, University of York, York YO10 5DD, UK
| | - Atsushi Fukuzawa
- King's College BHF Centre, Cardiovascular Division, London SE1 1UL, UK
| | - Sean T Sweeney
- Department of Biology, University of York, York YO10 5DD, UK
| | - Mathias Gautel
- King's College BHF Centre, Cardiovascular Division, London SE1 1UL, UK
| | - John Sparrow
- Department of Biology, University of York, York YO10 5DD, UK
| | - Belinda Bullard
- Department of Biology, University of York, York YO10 5DD, UK
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Abstract
Mutations in genes essential for protein homeostasis have been identified in frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) patients. Why mature neurons should be particularly sensitive to such perturbations is unclear. We identified mutations in Rab8 in a genetic screen for enhancement of an FTD phenotype associated with ESCRT-III dysfunction. Examination of Rab8 mutants or motor neurons expressing a mutant ESCRT-III subunit, CHMP2B(Intron5), at the Drosophila melanogaster neuromuscular junction synapse revealed synaptic overgrowth and endosomal dysfunction. Expression of Rab8 rescued overgrowth phenotypes generated by CHMP2B(Intron5). In Rab8 mutant synapses, c-Jun N-terminal kinase (JNK)/activator protein-1 and TGF-β signaling were overactivated and acted synergistically to potentiate synaptic growth. We identify novel roles for endosomal JNK-scaffold POSH (Plenty-of-SH3s) and a JNK kinase kinase, TAK1, in regulating growth activation in Rab8 mutants. Our data uncover Rab8, POSH, and TAK1 as regulators of synaptic growth responses and point to recycling endosome as a key compartment for synaptic growth regulation during neurodegenerative processes.
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Affiliation(s)
- Ryan J H West
- Department of Biology and Hull York Medical School, University of York, Heslington, York YO10 5DD, England, UK Department of Biology and Hull York Medical School, University of York, Heslington, York YO10 5DD, England, UK
| | - Yubing Lu
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Bruno Marie
- Institute of Neurobiology, Medical Sciences Campus, University of Puerto Rico, San Juan, Puerto Rico 00901
| | - Fen-Biao Gao
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Sean T Sweeney
- Department of Biology and Hull York Medical School, University of York, Heslington, York YO10 5DD, England, UK Department of Biology and Hull York Medical School, University of York, Heslington, York YO10 5DD, England, UK
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Abstract
Many neurodegenerative conditions have oxidative stress burdens where levels of reactive oxygen species (ROS) exceed the antioxidant capacity of the neuron. ROS can induce wide-ranging damage in a cell and this is prevented by the activation of antioxidant responses including autophagy. Jun-kinase (JNK) is stimulated by ROS and mediates antioxidant responses via the activation of the transcriptional activators Fos and Jun (AP-1). In recently published work we examined Drosophila mutants with overgrown larval neuromuscular synapses, mutants that also show all the hallmarks of lysosomal storage disease (LSD). We find that we can reverse this synaptic overgrowth by reducing the oxidative stress burden, and that synaptic overgrowth is mediated by autophagy and JNK-AP-1 activity. We also examined animals defective for protection from oxidative stress and found that they too have synapse overgrowth generated by JNK-AP-1 activity. Treatment of larvae with a known ROS-generating toxin, paraquat, yielded similar synaptic responses. The observations that oxidative stress responses, potentially acting through autophagy, can generate synaptic growth suggest that ROS may be a potent regulator of synapse size and function. These findings have intriguing implications for aging neurons, neurodegenerative conditions and the interpretation of metabolic demand during learning and memory.
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Affiliation(s)
- Ryan J H West
- Department of Biology and Hull-York Medical School, University of York, York, UK
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