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Garg V, Geurten BRH. Diving deep: zebrafish models in motor neuron degeneration research. Front Neurosci 2024; 18:1424025. [PMID: 38966756 PMCID: PMC11222423 DOI: 10.3389/fnins.2024.1424025] [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: 04/26/2024] [Accepted: 05/30/2024] [Indexed: 07/06/2024] Open
Abstract
In the dynamic landscape of biomedical science, the pursuit of effective treatments for motor neuron disorders like hereditary spastic paraplegia (HSP), amyotrophic lateral sclerosis (ALS), and spinal muscular atrophy (SMA) remains a key priority. Central to this endeavor is the development of robust animal models, with the zebrafish emerging as a prime candidate. Exhibiting embryonic transparency, a swift life cycle, and significant genetic and neuroanatomical congruencies with humans, zebrafish offer substantial potential for research. Despite the difference in locomotion-zebrafish undulate while humans use limbs, the zebrafish presents relevant phenotypic parallels to human motor control disorders, providing valuable insights into neurodegenerative diseases. This review explores the zebrafish's inherent traits and how they facilitate profound insights into the complex behavioral and cellular phenotypes associated with these disorders. Furthermore, we examine recent advancements in high-throughput drug screening using the zebrafish model, a promising avenue for identifying therapeutically potent compounds.
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Affiliation(s)
- Vranda Garg
- Department of Cellular Neurobiology, Georg-August-University Göttingen, Göttingen, Lower Saxony, Germany
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada
- Department of Neuroscience, Université de Montréal, Montreal, QC, Canada
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De Cock L, Bercier V, Van Den Bosch L. New developments in pre-clinical models of ALS to guide translation. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2024; 176:477-524. [PMID: 38802181 DOI: 10.1016/bs.irn.2024.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder in which selective death of motor neurons leads to muscle weakness and paralysis. Most research has focused on understanding and treating monogenic familial forms, most frequently caused by mutations in SOD1, FUS, TARDBP and C9orf72, although ALS is mostly sporadic and without a clear genetic cause. Rodent models have been developed to study monogenic ALS, but despite numerous pre-clinical studies and clinical trials, few disease-modifying therapies are available. ALS is a heterogeneous disease with complex underlying mechanisms where several genes and molecular pathways appear to play a role. One reason for the high failure rate of clinical translation from the current models could be oversimplification in pre-clinical studies. Here, we review advances in pre-clinical models to better capture the heterogeneous nature of ALS and discuss the value of novel model systems to guide translation and aid in the development of precision medicine.
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Affiliation(s)
- Lenja De Cock
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Louvain-University of Leuven, Leuven, Belgium; Center for Brain and Disease Research, Laboratory of Neurobiology, VIB, Leuven, Belgium
| | - Valérie Bercier
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Louvain-University of Leuven, Leuven, Belgium; Center for Brain and Disease Research, Laboratory of Neurobiology, VIB, Leuven, Belgium
| | - Ludo Van Den Bosch
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Louvain-University of Leuven, Leuven, Belgium; Center for Brain and Disease Research, Laboratory of Neurobiology, VIB, Leuven, Belgium.
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Martini L, Baek SH, Lo I, Raby BA, Silverman E, Weiss S, Glass K, Halu A. Detecting and dissecting signaling crosstalk via the multilayer network integration of signaling and regulatory interactions. Nucleic Acids Res 2024; 52:e5. [PMID: 37953325 PMCID: PMC10783515 DOI: 10.1093/nar/gkad1035] [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: 10/28/2022] [Revised: 06/27/2023] [Accepted: 10/23/2023] [Indexed: 11/14/2023] Open
Abstract
The versatility of cellular response arises from the communication, or crosstalk, of signaling pathways in a complex network of signaling and transcriptional regulatory interactions. Understanding the various mechanisms underlying crosstalk on a global scale requires untargeted computational approaches. We present a network-based statistical approach, MuXTalk, that uses high-dimensional edges called multilinks to model the unique ways in which signaling and regulatory interactions can interface. We demonstrate that the signaling-regulatory interface is located primarily in the intermediary region between signaling pathways where crosstalk occurs, and that multilinks can differentiate between distinct signaling-transcriptional mechanisms. Using statistically over-represented multilinks as proxies of crosstalk, we infer crosstalk among 60 signaling pathways, expanding currently available crosstalk databases by more than five-fold. MuXTalk surpasses existing methods in terms of model performance metrics, identifies additions to manual curation efforts, and pinpoints potential mediators of crosstalk. Moreover, it accommodates the inherent context-dependence of crosstalk, allowing future applications to cell type- and disease-specific crosstalk.
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Affiliation(s)
- Leonardo Martini
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, 02115, USA
- Department of Computer, Control, and Management Engineering, Sapienza University of Rome, Rome, 00185, Italy
| | - Seung Han Baek
- Division of Pulmonary Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Ian Lo
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Benjamin A Raby
- Division of Pulmonary Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Edwin K Silverman
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Scott T Weiss
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Kimberly Glass
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, 02115, USA
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Arda Halu
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, 02115, USA
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Chaoul V, Dib EY, Bedran J, Khoury C, Shmoury O, Harb F, Soueid J. Assessing Drug Administration Techniques in Zebrafish Models of Neurological Disease. Int J Mol Sci 2023; 24:14898. [PMID: 37834345 PMCID: PMC10573323 DOI: 10.3390/ijms241914898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 10/15/2023] Open
Abstract
Neurological diseases, including neurodegenerative and neurodevelopmental disorders, affect nearly one in six of the world's population. The burden of the resulting deaths and disability is set to rise during the next few decades as a consequence of an aging population. To address this, zebrafish have become increasingly prominent as a model for studying human neurological diseases and exploring potential therapies. Zebrafish offer numerous benefits, such as genetic homology and brain similarities, complementing traditional mammalian models and serving as a valuable tool for genetic screening and drug discovery. In this comprehensive review, we highlight various drug delivery techniques and systems employed for therapeutic interventions of neurological diseases in zebrafish, and evaluate their suitability. We also discuss the challenges encountered during this process and present potential advancements in innovative techniques.
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Affiliation(s)
- Victoria Chaoul
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut P.O. Box 11-0236, Lebanon; (V.C.); (J.B.); (O.S.)
| | - Emanuel-Youssef Dib
- Department of Biomedical Sciences, Faculty of Medicine and Medical Sciences, University of Balamand, Kalhat P.O. Box 100, Lebanon; (E.-Y.D.); (C.K.)
| | - Joe Bedran
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut P.O. Box 11-0236, Lebanon; (V.C.); (J.B.); (O.S.)
| | - Chakib Khoury
- Department of Biomedical Sciences, Faculty of Medicine and Medical Sciences, University of Balamand, Kalhat P.O. Box 100, Lebanon; (E.-Y.D.); (C.K.)
| | - Omar Shmoury
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut P.O. Box 11-0236, Lebanon; (V.C.); (J.B.); (O.S.)
| | - Frédéric Harb
- Department of Biomedical Sciences, Faculty of Medicine and Medical Sciences, University of Balamand, Kalhat P.O. Box 100, Lebanon; (E.-Y.D.); (C.K.)
| | - Jihane Soueid
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut P.O. Box 11-0236, Lebanon; (V.C.); (J.B.); (O.S.)
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5
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Wiesenfarth M, Huppertz HJ, Dorst J, Lulé D, Ludolph AC, Müller HP, Kassubek J. Structural and microstructural neuroimaging signature of C9orf72-associated ALS: A multiparametric MRI study. Neuroimage Clin 2023; 39:103505. [PMID: 37696099 PMCID: PMC10500452 DOI: 10.1016/j.nicl.2023.103505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/01/2023] [Accepted: 09/03/2023] [Indexed: 09/13/2023]
Abstract
BACKGROUND ALS patients with hexanucleotide expansion in C9orf72 are characterized by a specific clinical phenotype, including more aggressive disease course and cognitive decline. Computerized multiparametric MRI with gray matter volumetry and diffusion tensor imaging (DTI) to analyze white matter structural connectivity is a potential in vivo biomarker. OBJECTIVE The objective of this study was to develop a multiparametric MRI signature in a large cohort of ALS patients with C9orf72 mutations. The aim was to investigate how morphological features of C9orf72-associated ALS differ in structural MRI and DTI compared to healthy controls and ALS patients without C9orf72 mutations. METHODS Atlas-based volumetry (ABV) and whole brain-based DTI-based analyses were performed in a cohort of n = 51 ALS patients with C9orf72 mutations and compared with both n = 51 matched healthy controls and n = 51 C9orf72 negative ALS patients, respectively. Subsequently, Spearman correlation analysis of C9orf72 ALS patients' data with clinical parameters (age of onset, sex, ALS-FRS-R, progression rate, survival) as well as ECAS and p-NfH in CSF was performed. RESULTS The whole brain voxel-by-voxel comparison of fractional anisotropy (FA) maps between C9orf72 ALS patients and controls showed significant bilateral alterations in axonal structures of the white matter at group level, primarily along the corticospinal tracts and in fibers projecting to the frontal lobes. For the frontal lobes, these alterations were also significant between C9orf72 positive and C9orf72 negative ALS patients. In ABV, patients with C9orf72 mutations showed lower volumes of the frontal, temporal, and parietal lobe, with the lowest values in the gray matter of the superior frontal and the precentral gyrus, but also in hippocampi and amygdala. Compared to C9orf72 negative ALS, the differences were shown to be significant for cerebral gray matter (p = 0.04), especially in the frontal (p = 0.01) and parietal lobe (p = 0.01), and in the thalamus (p = 0.004). A correlation analysis between ECAS and averaged regional FA values revealed significant correlations between cognitive performance in ECAS and frontal association fibers. Lower FA values in the frontal lobes were associated with worse performance in all cognitive domains measured (language, verbal fluency, executive functions, memory and spatial perception). In addition, there were significant negative correlations between age of onset and atlas-based volumetry results for gray matter. CONCLUSIONS This study demonstrates a distinct pattern of DTI alterations of the white matter and ubiquitous volume reductions of the gray matter early in the disease course of C9orf72-associated ALS. Alterations were closely linked to a more aggressive cognitive phenotype. These results are in line with an expected pTDP43 propagation pattern of cortical affection and thus strengthen the hypothesis that an underlying developmental disorder is present in ALS with C9orf72 expansions. Thus, multiparametric MRI could contribute to the assessment of the disease as an in vivo biomarker even in the early phase of the disease.
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Affiliation(s)
| | | | - Johannes Dorst
- Department of Neurology, University Hospital Ulm, Ulm, Germany; German Centre of Neurodegenerative Diseases (DZNE), Ulm, Germany
| | - Dorothée Lulé
- Department of Neurology, University Hospital Ulm, Ulm, Germany
| | - Albert C Ludolph
- Department of Neurology, University Hospital Ulm, Ulm, Germany; German Centre of Neurodegenerative Diseases (DZNE), Ulm, Germany
| | | | - Jan Kassubek
- Department of Neurology, University Hospital Ulm, Ulm, Germany; German Centre of Neurodegenerative Diseases (DZNE), Ulm, Germany.
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Oliveira NAS, Pinho BR, Oliveira JMA. Swimming against ALS: How to model disease in zebrafish for pathophysiological and behavioral studies. Neurosci Biobehav Rev 2023; 148:105138. [PMID: 36933816 DOI: 10.1016/j.neubiorev.2023.105138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 03/02/2023] [Accepted: 03/14/2023] [Indexed: 03/18/2023]
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease that leads to progressive disability and motor impairment. Existing therapies provide modest improvements in patient survival, raising a need for new treatments for ALS. Zebrafish is a promising model animal for translational and fundamental research in ALS - it is an experimentally tractable vertebrate, with high homology to humans and an ample experimental toolbox. These advantages allow high-throughput study of behavioral and pathophysiological phenotypes. The last decade saw an increased interest in modelling ALS in zebrafish, leading to the current abundance and variety of available methods and models. Additionally, the rise of gene editing techniques and toxin combination studies has created novel opportunities for ALS studies in zebrafish. In this review, we address the relevance of zebrafish as a model animal for ALS studies, the strategies for model induction and key phenotypical evaluation. Furthermore, we discuss established and emerging zebrafish models of ALS, analyzing their validity, including their potential for drug testing, and highlighting research opportunities in this area.
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Affiliation(s)
- Nuno A S Oliveira
- UCIBIO-REQUIMTE, Applied Molecular Biosciences Unit, Mitochondria and Neurobiology Lab, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; Associate Laboratory i4HB, Institute for Health and Bioeconomy, Faculty of Pharmacy, Department of Drug Sciences, Pharmacology Lab, University of Porto, 4050-313 Porto, Portugal
| | - Brígida R Pinho
- UCIBIO-REQUIMTE, Applied Molecular Biosciences Unit, Mitochondria and Neurobiology Lab, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; Associate Laboratory i4HB, Institute for Health and Bioeconomy, Faculty of Pharmacy, Department of Drug Sciences, Pharmacology Lab, University of Porto, 4050-313 Porto, Portugal
| | - Jorge M A Oliveira
- UCIBIO-REQUIMTE, Applied Molecular Biosciences Unit, Mitochondria and Neurobiology Lab, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; Associate Laboratory i4HB, Institute for Health and Bioeconomy, Faculty of Pharmacy, Department of Drug Sciences, Pharmacology Lab, University of Porto, 4050-313 Porto, Portugal.
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Wang HL, Cheng YC, Yeh TH, Liu HF, Weng YH, Chen RS, Chen YC, Lu JC, Hwang TL, Wei KC, Liu YC, Wang YT, Hsu CC, Chiu TJ, Chiu CC. HCH6-1, an antagonist of formyl peptide receptor-1, exerts anti-neuroinflammatory and neuroprotective effects in cellular and animal models of Parkinson’s disease. Biochem Pharmacol 2023; 212:115524. [PMID: 37001680 DOI: 10.1016/j.bcp.2023.115524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 03/24/2023] [Indexed: 03/31/2023]
Abstract
Microglial activation-induced neuroinflammation contributes to onset and progression of sporadic and hereditary Parkinson's disease (PD). Activated microglia secrete pro-inflammatory and neurotoxic IL-1β, IL-6 and TNF-α, which subsequently promote neurodegeneration. Formyl peptide receptor-1 (FPR1) of CNS microglia functions as pattern recognition receptor and is activated by N-formylated peptides, leading to microglial activation, induction of inflammatory responses and resulting neurotoxicity. In this study, it was hypothesized that FPR1 activation of microglia causes loss of dopaminergic neurons by activating inflammasome and upregulating IL-1β, IL-6 or TNF-α and that FPR1 antagonist HCH6-1 exerts neuroprotective effect on dopaminergic neurons. FPR1 agonist fMLF induced activation of microglia cells by causing activation of NLRP3 inflammasome and upregulation and secretion of IL-1β, IL-6 or TNF-α. Conditioned medium (CM) of fMLF-treated microglia cells, which contains neurotoxic IL-1β, IL-6 and TNF-α, caused apoptotic death of differentiated SH-SY5Y dopaminergic neurons by inducing mitochondrial oxidative stress and activating pro-apoptotic signaling. FPR1 antagonist HCH6-1 prevented fMLF-induced activation of inflammasome and upregulation of pro-inflammatory cytokines in microglia cells. HCH6-1 co-treatment reversed CM of fMLF-treated microglia-induced apoptotic death of dopaminergic neurons. FPR1 antagonist HCH6-1 inhibited rotenone-induced upregulation of microglial marker Iba-1 protein level, cell death of dopaminergic neurons and motor impairment in zebrafish. HCH6-1 ameliorated rotenone-induced microglial activation, upregulation of FPR1 mRNA, activation of NLRP3 inflammasome, cell death of SN dopaminergic neurons and PD motor deficit in mice. Our results suggest that FPR1 antagonist HCH6-1 possesses anti-neuroinflammatory and neuroprotective effects on dopaminergic neurons by inhibiting microglial activation and upregulation of inflammasome activity and pro-inflammatory cytokines.
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Affiliation(s)
- Hung-Li Wang
- Department of Physiology and Pharmacology, Chang Gung University College of Medicine, Taoyuan, Taiwan; Division of Movement Disorders, Department of Neurology, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Healthy Aging Research Center, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Yi-Chuan Cheng
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Graduate Institute of Biomedical Sciences, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Tu-Hsueh Yeh
- Department of Neurology, Taipei Medical University Hospital, Taipei, Taiwan
| | - Han-Fang Liu
- Graduate Institute of Biomedical Sciences, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Yi-Hsin Weng
- Division of Movement Disorders, Department of Neurology, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Rou-Shayn Chen
- Division of Movement Disorders, Department of Neurology, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yi-Chun Chen
- College of Medicine, Chang Gung University, Taoyuan, Taiwan; Department of Neurology, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
| | - Juu-Chin Lu
- Department of Physiology and Pharmacology, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Tsong-Long Hwang
- Graduate Institute of Natural Products, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Department of Anesthesiology, Chang Gung Memorial Hospital, Taoyuan, Taiwan; Research Center for Chinese Herbal Medicine, Graduate Institute of Health Industry Technology, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan
| | - Kuo-Chen Wei
- College of Medicine, Chang Gung University, Taoyuan, Taiwan; Department of Neurosurgery, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
| | - Yu-Chuan Liu
- Division of Sports Medicine, Landseed International Hospital, Taoyuan, Taiwan
| | - Yu-Ting Wang
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chia-Chen Hsu
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Tai-Ju Chiu
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Ching-Chi Chiu
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Healthy Aging Research Center, Chang Gung University College of Medicine, Taoyuan, Taiwan; Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
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van Veenhuijzen K, Westeneng HJ, Tan HHG, Nitert AD, van der Burgh HK, Gosselt I, van Es MA, Nijboer TCW, Veldink JH, van den Berg LH. Longitudinal Effects of Asymptomatic C9orf72 Carriership on Brain Morphology. Ann Neurol 2022; 93:668-680. [PMID: 36511398 DOI: 10.1002/ana.26572] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 11/18/2022] [Accepted: 11/28/2022] [Indexed: 12/15/2022]
Abstract
OBJECTIVE We investigated effects of C9orf72 repeat expansion and gene expression on longitudinal cerebral changes before symptom onset. METHODS We enrolled 79 asymptomatic family members (AFMs) from 9 families with C9orf72 repeat expansion. Twenty-eight AFMs carried the mutation (C9+). Participants had up to 3 magnetic resonance imaging (MRI) scans, after which we compared motor cortex and motor tracts between C9+ and C9- AFMs using mixed effects models, incorporating kinship to correct for familial relations and lessen effects of other genetic factors. We also compared cortical, subcortical, cerebellar, and connectome structural measurements in a hypothesis-free analysis. We correlated regional C9orf72 expression in donor brains with the pattern of cortical thinning in C9+ AFMs using meta-regression. For comparison, we included 42 C9+ and 439 C9- patients with amyotrophic lateral sclerosis (ALS) in this analysis. RESULTS C9+ AFM motor cortex had less gyrification and was thinner than in C9- AFMs, without differences in motor tracts. Whole brain analysis revealed thinner cortex and less gyrification in parietal, occipital, and temporal regions, smaller thalami and right hippocampus, and affected frontotemporal connections. Thinning of bilateral precentral, precuneus, and left superior parietal cortex was faster in C9+ than in C9- AFMs. Higher C9orf72 expression correlated with thinner cortex in both C9+ AFMs and C9+ ALS patients. INTERPRETATION In asymptomatic C9orf72 repeat expansion carriers, brain MRI reveals widespread features suggestive of impaired neurodevelopment, along with faster decline of motor and parietal cortex than found in normal aging. C9orf72 expression might play a role in cortical development, and consequently explain the specific brain abnormalities of mutation carriers. ANN NEUROL 2022.
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Affiliation(s)
- Kevin van Veenhuijzen
- Department of Neurology, Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Henk-Jan Westeneng
- Department of Neurology, Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Harold H G Tan
- Department of Neurology, Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Abram D Nitert
- Department of Neurology, Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Hannelore K van der Burgh
- Department of Neurology, Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Isabel Gosselt
- Department of Neurology, Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands.,Center of Excellence for Rehabilitation Medicine, Brain Center, University Medical Center Utrecht and De Hoogstraat Rehabilitation, Utrecht, the Netherlands
| | - Michael A van Es
- Department of Neurology, Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Tanja C W Nijboer
- Department of Experimental Psychology, Utrecht University, Utrecht, the Netherlands
| | - Jan H Veldink
- Department of Neurology, Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Leonard H van den Berg
- Department of Neurology, Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
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9
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Finger E, Malik R, Bocchetta M, Coleman K, Graff C, Borroni B, Masellis M, Laforce R, Greaves CV, Russell LL, Convery RS, Bouzigues A, Cash DM, Otto M, Synofzik M, Rowe JB, Galimberti D, Tiraboschi P, Bartha R, Shoesmith C, Tartaglia MC, van Swieten JC, Seelaar H, Jiskoo LC, Sorbi S, Butler CR, Gerhard A, Sanchez-Valle R, de Mendonça A, Moreno F, Vandenberghe R, Le Ber I, Levin J, Pasquier F, Santana I, Rohrer JD, Ducharme S. Neurodevelopmental effects of genetic frontotemporal dementia in young adult mutation carriers. Brain 2022; 146:2120-2131. [PMID: 36458975 DOI: 10.1093/brain/awac446] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 10/05/2022] [Accepted: 10/16/2022] [Indexed: 12/03/2022] Open
Abstract
While frontotemporal dementia (frontotemporal dementia) has been considered a neurodegenerative disease that starts in mid-life or later, it is now clearly established that cortical and subcortical volume loss is observed more than a decade prior to symptom onset and progresses with aging. To test the hypothesis that genetic mutations causing frontotemporal dementia have neurodevelopmental consequences, we have examined the youngest adults in the GENFI cohort of pre-symptomatic frontotemporal dementia mutation carriers who are between the ages of 19 and 30y. Structural brain differences and improved performance on some cognitive tests was found for MAPT and GRN mutation carriers relative to familial non-carriers, while smaller volumes were observed in C9orf72 repeat expansion carriers at a mean age of 26y. The detection of such early differences supports potential advantageous neurodevelopmental consequences of some frontotemporal dementia causing genetic mutations. These results have implications for design of therapeutic interventions for frontotemporal dementia. Future studies at younger ages are needed to identify specific early pathophysiologic or compensatory processes in the neurodevelopmental period.
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Affiliation(s)
- Elizabeth Finger
- Department of Clinical Neurological Sciences, University of Western Ontario, London, ON, Canada
| | - Rubina Malik
- Schulich School of Medicine & Dentistry, Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada
| | - Martina Bocchetta
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Kristy Coleman
- Department of Clinical Neurological Sciences, University of Western Ontario, London, ON, Canada
| | - Caroline Graff
- Karolinska Institutet, Department NVS, Division of Neurogeriatrics, Stockholm, Sweden
- Unit for Hereditary Dementia, Theme Aging, Karolinska University Hospital-Solna Stockholm Sweden
| | - Barbara Borroni
- Centre for Neurodegenerative Disorders, Neurology Unit, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - Mario Masellis
- Campbell Cognitive Neurology Research Unit, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Robert Laforce
- Clinique Interdisciplinaire de Mémoire, Département des Sciences Neurologiques, CHU de Québec, Faculté de Médecine, Université Laval, Québec, Canada
| | - Caroline V Greaves
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Lucy L Russell
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Rhian S Convery
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Arabella Bouzigues
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - David M Cash
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Markus Otto
- Department of Neurology, University Hospital Ulm, Ulm, Germany
| | - Matthis Synofzik
- Division Translational Genomics of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research (HIH), University of Tübingen, Tübingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - James B Rowe
- Department of Clinical Neurosciences and Cambridge University Hospitals NHS Trust and Medical Research Council Cognition and brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Daniela Galimberti
- Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy
- Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | | | - Robert Bartha
- Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada
| | - Christen Shoesmith
- Department of Clinical Neurological Sciences, University of Western Ontario, London, ON, Canada
| | - Maria Carmela Tartaglia
- Toronto Western Hospital, Tanz Centre for Research in Neurodegenerative Disease, Toronto, ON, Canada
| | - John C van Swieten
- Department of Neurology and Alzheimer center, Erasmus Medical Center Rotterdam, the Netherlands
| | - Harro Seelaar
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Lize C Jiskoo
- Department of Neurology and Alzheimer center, Erasmus Medical Center Rotterdam, the Netherlands
| | - Sandro Sorbi
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Chris R Butler
- Department of Clinical Neurology, University of Oxford, Oxford, UK
| | - Alexander Gerhard
- Division of Neuroscience and Experimental Psychology, Wolfson Molecular Imaging Centre, University of Manchester, Manchester, UK
- Departments of Geriatric Medicine and Nuclear Medicine, University of Duisburg-Essen, Germany
| | - Raquel Sanchez-Valle
- Neurology Department, Hospital Clinic, Institut d'Investigacions Biomèdiques, Barcelona, Spain
| | | | - Fermin Moreno
- Hospital Universitario Donostia, San Sebastian, Spain
| | - Rik Vandenberghe
- Laboratory for Cognitive Neurology, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Isabelle Le Ber
- Sorbonne Université, Paris Brain Institute - Institut du Cerveau - ICM, Inserm U1127, CNRS UMR 7225, AP-HP - Hôpital Pitié-Salpêtrière, Paris, France
- Centre de référence des démences rares ou précoces, IM2A, Département de Neurologie, AP-HP - Hôpital Pitié-Salpêtrière, Paris, France
- Département de Neurologie, AP-HP - Hôpital Pitié-Salpêtrière, Paris, France
| | - Johannes Levin
- Neurologische Klinik und Poliklinik, Ludwig-Maximilians-Universität, Munich; German Center for Neurodegenerative Diseases (DZNE), Munich; Munich Cluster of Systems Neurology, Munich, Germany
| | - Florence Pasquier
- Univ Lille, Lille, France
- Inserm 1172, Lille, France
- CHU, CNR-MAJ, Labex Distalz, LiCEND, Lille, France
| | - Isabel Santana
- Neurology Department, Centro Hospitalar e Universitário de Coimbra, Portugal
| | - Jonathan D Rohrer
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Simon Ducharme
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
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10
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Chia K, Klingseisen A, Sieger D, Priller J. Zebrafish as a model organism for neurodegenerative disease. Front Mol Neurosci 2022; 15:940484. [PMID: 36311026 PMCID: PMC9606821 DOI: 10.3389/fnmol.2022.940484] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 07/01/2022] [Indexed: 11/20/2022] Open
Abstract
The zebrafish is increasingly recognized as a model organism for translational research into human neuropathology. The zebrafish brain exhibits fundamental resemblance with human neuroanatomical and neurochemical pathways, and hallmarks of human brain pathology such as protein aggregation, neuronal degeneration and activation of glial cells, for example, can be modeled and recapitulated in the fish central nervous system. Genetic manipulation, imaging, and drug screening are areas where zebrafish excel with the ease of introducing mutations and transgenes, the expression of fluorescent markers that can be detected in vivo in the transparent larval stages overtime, and simple treatment of large numbers of fish larvae at once followed by automated screening and imaging. In this review, we summarize how zebrafish have successfully been employed to model human neurodegenerative diseases such as Parkinson’s disease, Alzheimer’s disease, amyotrophic lateral sclerosis, and Huntington’s disease. We discuss advantages and disadvantages of choosing zebrafish as a model for these neurodegenerative conditions.
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Affiliation(s)
- Kelda Chia
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- United Kingdom Dementia Research Institute at University of Edinburgh, Edinburgh, United Kingdom
| | - Anna Klingseisen
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- United Kingdom Dementia Research Institute at University of Edinburgh, Edinburgh, United Kingdom
| | - Dirk Sieger
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- *Correspondence: Dirk Sieger,
| | - Josef Priller
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- United Kingdom Dementia Research Institute at University of Edinburgh, Edinburgh, United Kingdom
- Department of Psychiatry and Psychotherapy, School of Medicine, Technical University of Munich, Munich, Germany
- Neuropsychiatry and Laboratory of Molecular Psychiatry, Charité - Universitätsmedizin Berlin, DZNE, Berlin, Germany
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
- Josef Priller,
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11
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Lescouzères L, Bordignon B, Bomont P. Development of a high-throughput tailored imaging method in zebrafish to understand and treat neuromuscular diseases. Front Mol Neurosci 2022; 15:956582. [PMID: 36204134 PMCID: PMC9530744 DOI: 10.3389/fnmol.2022.956582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 08/16/2022] [Indexed: 11/13/2022] Open
Abstract
The zebrafish (Danio rerio) is a vertebrate species offering multitude of advantages for the study of conserved biological systems in human and has considerably enriched our knowledge in developmental biology and physiology. Being equally important in medical research, the zebrafish has become a critical tool in the fields of diagnosis, gene discovery, disease modeling, and pharmacology-based therapy. Studies on the zebrafish neuromuscular system allowed for deciphering key molecular pathways in this tissue, and established it as a model of choice to study numerous motor neurons, neuromuscular junctions, and muscle diseases. Starting with the similarities of the zebrafish neuromuscular system with the human system, we review disease models associated with the neuromuscular system to focus on current methodologies employed to study them and outline their caveats. In particular, we put in perspective the necessity to develop standardized and high-resolution methodologies that are necessary to deepen our understanding of not only fundamental signaling pathways in a healthy tissue but also the changes leading to disease phenotype outbreaks, and offer templates for high-content screening strategies. While the development of high-throughput methodologies is underway for motility assays, there is no automated approach to quantify the key molecular cues of the neuromuscular junction. Here, we provide a novel high-throughput imaging methodology in the zebrafish that is standardized, highly resolutive, quantitative, and fit for drug screening. By providing a proof of concept for its robustness in identifying novel molecular players and therapeutic drugs in giant axonal neuropathy (GAN) disease, we foresee that this new tool could be useful for both fundamental and biomedical research.
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Affiliation(s)
- Léa Lescouzères
- ERC Team, Institut NeuroMyoGéne-PGNM, Inserm U1315, CNRS UMR 5261, Claude Bernard University Lyon 1, Lyon, France
| | - Benoît Bordignon
- Montpellier Ressources Imagerie, BioCampus, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Pascale Bomont
- ERC Team, Institut NeuroMyoGéne-PGNM, Inserm U1315, CNRS UMR 5261, Claude Bernard University Lyon 1, Lyon, France
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12
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McKenna MC, Lope J, Tan EL, Bede P. Pre-symptomatic radiological changes in frontotemporal dementia: propagation characteristics, predictive value and implications for clinical trials. Brain Imaging Behav 2022; 16:2755-2767. [PMID: 35920960 DOI: 10.1007/s11682-022-00711-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2022] [Indexed: 11/25/2022]
Abstract
Computational imaging and quantitative biomarkers offer invaluable insights in the pre-symptomatic phase of neurodegenerative conditions several years before clinical manifestation. In recent years, there has been a focused effort to characterize pre-symptomatic cerebral changes in familial frontotemporal dementias using computational imaging. Accordingly, a systematic literature review was conducted of original articles investigating pre-symptomatic imaging changes in frontotemporal dementia focusing on study design, imaging modalities, data interpretation, control cohorts and key findings. The review is limited to the most common genotypes: chromosome 9 open reading frame 72 (C9orf72), progranulin (GRN), or microtubule-associated protein tau (MAPT) genotypes. Sixty-eight studies were identified with a median sample size of 15 (3-141) per genotype. Only a minority of studies were longitudinal (28%; 19/68) with a median follow-up of 2 (1-8) years. MRI (97%; 66/68) was the most common imaging modality, and primarily grey matter analyses were conducted (75%; 19/68). Some studies used multimodal analyses 44% (30/68). Genotype-associated imaging signatures are presented, innovative study designs are highlighted, common methodological shortcomings are discussed and lessons for future studies are outlined. Emerging academic observations have potential clinical implications for expediting the diagnosis, tracking disease progression and optimising the timing of pharmaceutical trials.
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Affiliation(s)
- Mary Clare McKenna
- Computational Neuroimaging Group, Biomedical Sciences Institute, Trinity College Dublin, Room 5.43, Pearse Street, Dublin 2, Ireland.,Department of Neurology, St James's Hospital, Dublin, Ireland
| | - Jasmin Lope
- Computational Neuroimaging Group, Biomedical Sciences Institute, Trinity College Dublin, Room 5.43, Pearse Street, Dublin 2, Ireland
| | - Ee Ling Tan
- Computational Neuroimaging Group, Biomedical Sciences Institute, Trinity College Dublin, Room 5.43, Pearse Street, Dublin 2, Ireland
| | - Peter Bede
- Computational Neuroimaging Group, Biomedical Sciences Institute, Trinity College Dublin, Room 5.43, Pearse Street, Dublin 2, Ireland. .,Department of Neurology, St James's Hospital, Dublin, Ireland.
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13
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A nop56 Zebrafish Loss-of-Function Model Exhibits a Severe Neurodegenerative Phenotype. Biomedicines 2022; 10:biomedicines10081814. [PMID: 36009362 PMCID: PMC9404972 DOI: 10.3390/biomedicines10081814] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 07/21/2022] [Accepted: 07/22/2022] [Indexed: 11/17/2022] Open
Abstract
NOP56 belongs to a C/D box small nucleolar ribonucleoprotein complex that is in charge of cleavage and modification of precursor ribosomal RNAs and assembly of the 60S ribosomal subunit. An intronic expansion in NOP56 gene causes Spinocerebellar Ataxia type 36, a typical late-onset autosomal dominant ataxia. Although vertebrate animal models were created for the intronic expansion, none was studied for the loss of function of NOP56. We studied a zebrafish loss-of-function model of the nop56 gene which shows 70% homology with the human gene. We observed a severe neurodegenerative phenotype in nop56 mutants, characterized mainly by absence of cerebellum, reduced numbers of spinal cord neurons, high levels of apoptosis in the central nervous system (CNS) and impaired movement, resulting in death before 7 days post-fertilization. Gene expression of genes related to C/D box complex, balance and CNS development was impaired in nop56 mutants. In our study, we characterized the first NOP56 loss-of-function vertebrate model, which is important to further understand the role of NOP56 in CNS function and development.
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14
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Liu Y, Xing H, Ernst AF, Liu C, Maugee C, Yokoi F, Lakshmana M, Li Y. Hyperactivity of Purkinje cell and motor deficits in C9orf72 knockout mice. Mol Cell Neurosci 2022; 121:103756. [PMID: 35843530 PMCID: PMC10369482 DOI: 10.1016/j.mcn.2022.103756] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 07/11/2022] [Indexed: 10/17/2022] Open
Abstract
A hexanucleotide (GGGGCC) repeat expansion in the first intron of the C9ORF72 gene is the most frequently reported genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The cerebellum has not traditionally been thought to be involved in the pathogenesis of C9ORF72-associated ALS/FTD, but recent evidence suggested a potential role. C9ORF72 is highly expressed in the cerebellum. Decreased C9ORF72 transcript and protein levels were detected in the postmortem cerebellum, suggesting a loss-of-function effect of C9ORF72 mutation. This study investigated the role of loss of C9ORF72 function using a C9orf72 knockout mouse line. C9orf72 deficiency led to motor impairment in rotarod, beam-walking, paw-print, open-field, and grip-strength tests. Purkinje cells are the sole output neurons in the cerebellum, and we next determined their involvement in the motor phenotypes. We found hyperactivity of Purkinje cells in the C9orf72 knockout mouse accompanied by a significant increase of the large-conductance calcium-activated potassium channel (BK) protein in the cerebellum. The link between BK and Purkinje cell firing was demonstrated by the acute application of the BK activator that increased the firing frequency of the Purkinje cells ex vivo. In vivo chemogenetic activation of Purkinje cells in wild-type mice led to similar motor deficits in rotarod and beam-walking tests. Our results highlight that C9ORF72 loss alters the activity of the Purkinje cell and potentially the pathogenesis of the disease. Manipulating the Purkinje cell firing or cerebellar output may contribute to C9ORF72-associated ALS/FTD treatment.
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Affiliation(s)
- Yuning Liu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States; Genetics Institute, University of Florida, Gainesville, FL, United States
| | - Hong Xing
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Alexis F Ernst
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Canna Liu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Christian Maugee
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States; Genetics Institute, University of Florida, Gainesville, FL, United States
| | - Fumiaki Yokoi
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Madepalli Lakshmana
- Department of Immunology and Nano-Medicine, The Herbert Wertheim College of Medicine, Florida International University, Miami, FL, United States
| | - Yuqing Li
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States.
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15
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How can we define the presymptomatic C9orf72 disease in 2022? An overview on the current definitions of preclinical and prodromal phases. Rev Neurol (Paris) 2022; 178:426-436. [PMID: 35525633 DOI: 10.1016/j.neurol.2022.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 03/08/2022] [Indexed: 11/24/2022]
Abstract
Repeat expansions in C9orf72 gene are the main genetic cause of frontotemporal dementia, amyotrophic lateral sclerosis and related phenotypes. With the advent of disease-modifying treatments, the presymptomatic disease phase is getting increasing interest as an ideal time window in which innovant therapeutic approaches could be administered. Recommendations issued from international study groups distinguish between a preclinical disease stage, during which lesions accumulate in absence of any symptoms or signs, and a prodromal stage, marked by the appearance the first subtle cognitive, behavioral, psychiatric and motor signs, before the full-blown disease. This paper summarizes the current definitions and criteria for these stages, in particular focusing on how fluid-based, neuroimaging and cognitive biomarkers can be useful to monitor disease trajectory across the presymptomatic phase, as well as to detect the earliest signs of clinical conversion. Continuous advances in the knowledge of C9orf72 pathophysiology, and the integration of biomarkers in the clinical evaluation of mutation carriers will allow a better diagnostic definition of C9orf72 disease spectrum from the earliest stages, with relevant impact on the possibility of disease prevention.
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16
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Jiang L, Zhang T, Lu K, Qi S. The progress in C9orf72 research: ALS/FTD pathogenesis, functions and structure. Small GTPases 2022; 13:56-76. [PMID: 33663328 PMCID: PMC9707547 DOI: 10.1080/21541248.2021.1892443] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The hexanucleotide repeat (GGGGCC) expansion in C9orf72 is accounted for a large proportion of the genetic amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The hypotheses of how the massive G4C2 repeats in C9orf72 destroy the neurons and lead to ALS/FTD are raised and improving. As a multirole player, C9orf72 exerts critical roles in many cellular processes, including autophagy, membrane trafficking, immune response, and so on. Notably, the partners of C9orf72, through which C9orf72 participates in the cell activities, have been identified. Notably, the structures of the C9orf72-SMCR8-WDR41 complex shed light on its activity as GTPase activating proteins (GAP). In this manuscript, we reviewed the latest research progress in the C9orf72-mediated ALS/FTD, the physiological functions of C9orf72, and the putative function models of C9orf72/C9orf72-containing complex.
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Affiliation(s)
- Lan Jiang
- Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, Chengdu, China
| | - Tizhong Zhang
- Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, Chengdu, China
| | - Kefeng Lu
- Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, Chengdu, China
| | - Shiqian Qi
- Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, Chengdu, China,CONTACT Shiqian Qi Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, Chengdu, China.
These authors contributed equally to this work.
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17
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Kisby GE, Spencer PS. Genotoxic Damage During Brain Development Presages Prototypical Neurodegenerative Disease. Front Neurosci 2021; 15:752153. [PMID: 34924930 PMCID: PMC8675606 DOI: 10.3389/fnins.2021.752153] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 10/20/2021] [Indexed: 01/15/2023] Open
Abstract
Western Pacific Amyotrophic Lateral Sclerosis and Parkinsonism-Dementia Complex (ALS/PDC) is a disappearing prototypical neurodegenerative disorder (tau-dominated polyproteinopathy) linked with prior exposure to phytogenotoxins in cycad seed used for medicine and/or food. The principal cycad genotoxin, methylazoxymethanol (MAM), forms reactive carbon-centered ions that alkylate nucleic acids in fetal rodent brain and, depending on the timing of systemic administration, induces persistent developmental abnormalities of the cortex, hippocampus, cerebellum, and retina. Whereas administration of MAM prenatally or postnatally can produce animal models of epilepsy, schizophrenia or ataxia, administration to adult animals produces little effect on brain structure or function. The neurotoxic effects of MAM administered to rats during cortical brain development (specifically, gestation day 17) are used to model the histological, neurophysiological and behavioral deficits of human schizophrenia, a condition that may precede or follow clinical onset of motor neuron disease in subjects with sporadic ALS and ALS/PDC. While studies of migrants to and from communities impacted by ALS/PDC indicate the degenerative brain disorder may be acquired in juvenile and adult life, a proportion of indigenous cases shows neurodevelopmental aberrations in the cerebellum and retina consistent with MAM exposure in utero. MAM induces specific patterns of DNA damage and repair that associate with increased tau expression in primary rat neuronal cultures and with brain transcriptional changes that parallel those associated with human ALS and Alzheimer's disease. We examine MAM in relation to neurodevelopment, epigenetic modification, DNA damage/replicative stress, genomic instability, somatic mutation, cell-cycle reentry and cellular senescence. Since the majority of neurodegenerative disease lacks a solely inherited genetic basis, research is needed to explore the hypothesis that early-life exposure to genotoxic agents may trigger or promote molecular events that culminate in neurodegeneration.
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Affiliation(s)
- Glen E. Kisby
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Lebanon, OR, United States
| | - Peter S. Spencer
- School of Medicine (Neurology), Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, United States
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18
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Bonifacino T, Zerbo RA, Balbi M, Torazza C, Frumento G, Fedele E, Bonanno G, Milanese M. Nearly 30 Years of Animal Models to Study Amyotrophic Lateral Sclerosis: A Historical Overview and Future Perspectives. Int J Mol Sci 2021; 22:ijms222212236. [PMID: 34830115 PMCID: PMC8619465 DOI: 10.3390/ijms222212236] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 12/20/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal, multigenic, multifactorial, and non-cell autonomous neurodegenerative disease characterized by upper and lower motor neuron loss. Several genetic mutations lead to ALS development and many emerging gene mutations have been discovered in recent years. Over the decades since 1990, several animal models have been generated to study ALS pathology including both vertebrates and invertebrates such as yeast, worms, flies, zebrafish, mice, rats, guinea pigs, dogs, and non-human primates. Although these models show different peculiarities, they are all useful and complementary to dissect the pathological mechanisms at the basis of motor neuron degeneration and ALS progression, thus contributing to the development of new promising therapeutics. In this review, we describe the up to date and available ALS genetic animal models, classified by the different genetic mutations and divided per species, pointing out their features in modeling, the onset and progression of the pathology, as well as their specific pathological hallmarks. Moreover, we highlight similarities, differences, advantages, and limitations, aimed at helping the researcher to select the most appropriate experimental animal model, when designing a preclinical ALS study.
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Affiliation(s)
- Tiziana Bonifacino
- Pharmacology and Toxicology Unit, Department of Pharmacy, University of Genoa, 16148 Genoa, Italy; (T.B.); (R.A.Z.); (M.B.); (C.T.); (G.F.); (G.B.); (M.M.)
- Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), 56122 Genoa, Italy
| | - Roberta Arianna Zerbo
- Pharmacology and Toxicology Unit, Department of Pharmacy, University of Genoa, 16148 Genoa, Italy; (T.B.); (R.A.Z.); (M.B.); (C.T.); (G.F.); (G.B.); (M.M.)
| | - Matilde Balbi
- Pharmacology and Toxicology Unit, Department of Pharmacy, University of Genoa, 16148 Genoa, Italy; (T.B.); (R.A.Z.); (M.B.); (C.T.); (G.F.); (G.B.); (M.M.)
| | - Carola Torazza
- Pharmacology and Toxicology Unit, Department of Pharmacy, University of Genoa, 16148 Genoa, Italy; (T.B.); (R.A.Z.); (M.B.); (C.T.); (G.F.); (G.B.); (M.M.)
| | - Giulia Frumento
- Pharmacology and Toxicology Unit, Department of Pharmacy, University of Genoa, 16148 Genoa, Italy; (T.B.); (R.A.Z.); (M.B.); (C.T.); (G.F.); (G.B.); (M.M.)
| | - Ernesto Fedele
- Pharmacology and Toxicology Unit, Department of Pharmacy, University of Genoa, 16148 Genoa, Italy; (T.B.); (R.A.Z.); (M.B.); (C.T.); (G.F.); (G.B.); (M.M.)
- IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy
- Correspondence:
| | - Giambattista Bonanno
- Pharmacology and Toxicology Unit, Department of Pharmacy, University of Genoa, 16148 Genoa, Italy; (T.B.); (R.A.Z.); (M.B.); (C.T.); (G.F.); (G.B.); (M.M.)
- IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy
| | - Marco Milanese
- Pharmacology and Toxicology Unit, Department of Pharmacy, University of Genoa, 16148 Genoa, Italy; (T.B.); (R.A.Z.); (M.B.); (C.T.); (G.F.); (G.B.); (M.M.)
- Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), 56122 Genoa, Italy
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19
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Torres P, Cabral-Miranda F, Gonzalez-Teuber V, Hetz C. Proteostasis deregulation as a driver of C9ORF72 pathogenesis. J Neurochem 2021; 159:941-957. [PMID: 34679204 DOI: 10.1111/jnc.15529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 10/16/2021] [Accepted: 10/18/2021] [Indexed: 12/21/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are two related neurodegenerative disorders that display overlapping features. The hexanucleotide repeat expansion GGGGCC (G4 C2 ) in C9ORF72 gene has been causally linked to both ALS and FTD emergence, thus opening a novel potential therapeutic target for disease intervention. The main driver of C9ORF72 pathology is the disruption of distinct cellular processes involved in the function of the proteostasis network. Here we discuss main findings relating to the induction of neurodegeneration by C9ORF72 mutation and proteostasis deregulation, highlighting the role of the endoplasmic reticulum stress, nuclear transport, and autophagy in the disease process. We further discuss possible points of intervention to target proteostasis mediators to treat C9ORF72-linked ALS/FTD.
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Affiliation(s)
- Paulina Torres
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile, Santiago, Chile.,FONDAP Center for Geroscience, Brain Health, and Metabolism (GERO), Santiago, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Science, University of Chile, Santiago, Chile
| | - Felipe Cabral-Miranda
- Instituto de Ciências Biomédicas, Universidade do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Vicente Gonzalez-Teuber
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile, Santiago, Chile.,FONDAP Center for Geroscience, Brain Health, and Metabolism (GERO), Santiago, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Science, University of Chile, Santiago, Chile
| | - Claudio Hetz
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile, Santiago, Chile.,FONDAP Center for Geroscience, Brain Health, and Metabolism (GERO), Santiago, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Science, University of Chile, Santiago, Chile.,Buck Institute for Research on Aging, Novato, California, USA
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20
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Wang J, Cao H. Zebrafish and Medaka: Important Animal Models for Human Neurodegenerative Diseases. Int J Mol Sci 2021; 22:10766. [PMID: 34639106 PMCID: PMC8509648 DOI: 10.3390/ijms221910766] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/30/2021] [Accepted: 09/30/2021] [Indexed: 02/06/2023] Open
Abstract
Animal models of human neurodegenerative disease have been investigated for several decades. In recent years, zebrafish (Danio rerio) and medaka (Oryzias latipes) have become popular in pathogenic and therapeutic studies about human neurodegenerative diseases due to their small size, the optical clarity of embryos, their fast development, and their suitability to large-scale therapeutic screening. Following the emergence of a new generation of molecular biological technologies such as reverse and forward genetics, morpholino, transgenesis, and gene knockout, many human neurodegenerative disease models, such as Parkinson's, Huntington's, and Alzheimer's, were constructed in zebrafish and medaka. These studies proved that zebrafish and medaka genes are functionally conserved in relation to their human homologues, so they exhibit similar neurodegenerative phenotypes to human beings. Therefore, fish are a suitable model for the investigation of pathologic mechanisms of neurodegenerative diseases and for the large-scale screening of drugs for potential therapy. In this review, we summarize the studies in modelling human neurodegenerative diseases in zebrafish and medaka in recent years.
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Affiliation(s)
- Jing Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu South Road 7#, Wuhan 430072, China;
- College of Advanced Agriculture Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong Cao
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu South Road 7#, Wuhan 430072, China;
- College of Advanced Agriculture Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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21
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Yeh TH, Liu HF, Chiu CC, Cheng ML, Huang GJ, Huang YC, Liu YC, Huang YZ, Lu CS, Chen YC, Chen HY, Cheng YC. PLA2G6 mutations cause motor dysfunction phenotypes of young-onset dystonia-parkinsonism type 14 and can be relieved by DHA treatment in animal models. Exp Neurol 2021; 346:113863. [PMID: 34520727 DOI: 10.1016/j.expneurol.2021.113863] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 08/30/2021] [Accepted: 09/08/2021] [Indexed: 10/20/2022]
Abstract
Parkinson's disease (PD), the most common neurodegenerative motor disorder, is currently incurable. Although many studies have provided insights on the substantial influence of genetic factors on the occurrence and development of PD, the molecular mechanism underlying the disease is largely unclear. Previous studies have shown that point mutations in the phospholipase A2 group VI gene (PLA2G6) correlate with young-onset dystonia-parkinsonism type 14 (PARK14). However, limited information is available regarding the pathogenic role of this gene and the mechanism underlying its function. To study the role of PLA2G6 mutations, we first used zebrafish larvae to screen six PLA2G6 mutations and revealed that injection of D331Y, T572I, and R741Q mutation constructs induced phenotypes such as motility defects and reduction in dopaminergic neurons. The motility defects could be alleviated by treatment with L-3, 4-dihydroxyphenylalanine (L-dopa), indicating that these mutations are pathological for PARK14 symptoms. Furthermore, the injection of D331Y and T572I mutation constructs reduced phospholipase activity of PLA2G6 and its lipid metabolites, which confirmed that these two mutations are loss-of-function mutations. Metabolomic analysis revealed that D331Y or T572I mutation led to higher phospholipid and lower docosahexaenoic acid (DHA) levels, indicating that reduced DHA levels are pathological for defective motor functions. Further, a dietary DHA supplement relieved the motility defects in PLA2G6D331Y/D331Y knock-in mice. This result revealed that the D331Y mutation caused defective PLA2G6 phospholipase activity and consequently reduced the DHA level, which is the pathogenic factor responsible for PARK14. The results of this study will facilitate the development of therapeutic strategies for PARK14.
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Affiliation(s)
- Tu-Hsueh Yeh
- Department of Neurology, Taipei Medical University Hospital, Taipei, Taiwan; School of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Han-Fang Liu
- College of Medicine, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Ching-Chi Chiu
- College of Medicine, Chang Gung University, Taoyuan, Taiwan; Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan; Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan
| | - Mei-Ling Cheng
- Department of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan.; Metabolomics Core Laboratory, Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan; Clinical Metabolomics Core Laboratory, Chang Gung Memorial Hospital, Taoyuan City, Taiwan
| | - Guo-Jen Huang
- Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan; Department of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - Yin-Cheng Huang
- College of Medicine, Chang Gung University, Taoyuan, Taiwan; Department of Neurosurgery, Chang Gung Memorial Hospital at Linkou Medical Center, Taoyuan, Taiwan
| | - Yu-Chien Liu
- College of Medicine, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Ying-Zu Huang
- Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan; Department of Neurology, Chang Gung Memorial Hospital at Linkou Medical Center, Taoyuan, Taiwan
| | - Chin-Song Lu
- Department of Neurology, Chang Gung Memorial Hospital at Linkou Medical Center, Taoyuan, Taiwan; Section of Movement Disorders, Department of Neurology, Chang Gung Memorial Hospital at Linkou Medical Center, Taoyuan, Taiwan
| | - Yi-Chieh Chen
- Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan; Department of Neurology, Chang Gung Memorial Hospital at Linkou Medical Center, Taoyuan, Taiwan
| | - Hao-Yuan Chen
- College of Medicine, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yi-Chuan Cheng
- College of Medicine, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan.
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22
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Behler A, Knehr A, Finsel J, Kunz MS, Lang C, Müller K, Müller HP, Pinkhardt EH, Ludolph AC, Lulé D, Kassubek J. Eye movement alterations in presymptomatic C9orf72 expansion gene carriers. J Neurol 2021; 268:3390-3399. [PMID: 33709219 PMCID: PMC8357645 DOI: 10.1007/s00415-021-10510-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/04/2021] [Accepted: 03/05/2021] [Indexed: 11/29/2022]
Abstract
Objective The clinical manifestation of amyotrophic lateral sclerosis (ALS) is characterized by motor neuron degeneration, whereas frontotemporal dementia (FTD) patients show alterations of behavior and cognition. Both share repeat expansions in C9orf72 as the most prevalent genetic cause. Before disease-defining symptoms onset, structural and functional changes at cortical level may emerge in C9orf72 carriers. Here, we characterized oculomotor parameters and their association to neuropsychological domains in apparently asymptomatic individuals with mutations in ALS/FTD genes. Patients and methods Forty-eight carriers of ALS genes, without any clinical symptoms underwent video-oculographic examination, including 22 subjects with C9orf72 mutation, 17 with SOD1, and 9 with other ALS associated gene mutations (n = 3 KIF5A; n = 3 FUS/FUS + TBK1; n = 1 NEK1; n = 1 SETX; n = 1 TDP43). A total of 17 subjects underwent a follow-up measurement. Data were compared to 54 age- and gender-matched healthy controls. Additionally, mutation carriers performed a neuropsychological assessment. Results In comparison to controls, the presymptomatic subjects performed significantly worse in executive oculomotor tasks such as the ability to perform correct anti-saccades. A gene mutation subgroup analysis showed that dysfunctions in C9orf72 carriers were much more pronounced than in SOD1 carriers. The anti-saccade error rate of ALS mutation carriers was associated with cognitive deficits: this correlation was increased in subjects with C9orf72 mutation, whereas SOD1 carriers showed no associations. Conclusion In C9orf72 carriers, executive eye movement dysfunctions, especially the increased anti-saccade error rate, were associated with cognitive impairment and unrelated to time. These oculomotor impairments are in support of developmental deficits in these mutations, especially in prefrontal areas.
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Affiliation(s)
- Anna Behler
- Department of Neurology, University of Ulm, Oberer Eselsberg 45, 89081, Ulm, Germany
| | - Antje Knehr
- Department of Neurology, University of Ulm, Oberer Eselsberg 45, 89081, Ulm, Germany
| | - Julia Finsel
- Neuropsychology, Department of Neurology, University of Ulm, Ulm, Germany
| | - Martin S Kunz
- Department of Neurology, University of Ulm, Oberer Eselsberg 45, 89081, Ulm, Germany
| | - Christina Lang
- Department of Neurology, University of Ulm, Oberer Eselsberg 45, 89081, Ulm, Germany
| | - Kathrin Müller
- Department of Neurology, University of Ulm, Oberer Eselsberg 45, 89081, Ulm, Germany
| | - Hans-Peter Müller
- Department of Neurology, University of Ulm, Oberer Eselsberg 45, 89081, Ulm, Germany
| | - Elmar H Pinkhardt
- Department of Neurology, University of Ulm, Oberer Eselsberg 45, 89081, Ulm, Germany
| | - Albert C Ludolph
- Department of Neurology, University of Ulm, Oberer Eselsberg 45, 89081, Ulm, Germany
| | - Dorothée Lulé
- Neuropsychology, Department of Neurology, University of Ulm, Ulm, Germany
| | - Jan Kassubek
- Department of Neurology, University of Ulm, Oberer Eselsberg 45, 89081, Ulm, Germany.
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23
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Gagliardi D, Costamagna G, Taiana M, Andreoli L, Biella F, Bersani M, Bresolin N, Comi GP, Corti S. Insights into disease mechanisms and potential therapeutics for C9orf72-related amyotrophic lateral sclerosis/frontotemporal dementia. Ageing Res Rev 2020; 64:101172. [PMID: 32971256 DOI: 10.1016/j.arr.2020.101172] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 08/31/2020] [Indexed: 12/12/2022]
Abstract
In 2011, a hexanucleotide repeat expansion (HRE) in the noncoding region of C9orf72 was associated with the most frequent genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). The main pathogenic mechanisms in C9-ALS/FTD are haploinsufficiency of the C9orf72 protein and gain of function toxicity from bidirectionally-transcribed repeat-containing RNAs and dipeptide repeat proteins (DPRs) resulting from non-canonical RNA translation. Additionally, abnormalities in different downstream cellular mechanisms, such as nucleocytoplasmic transport and autophagy, play a role in pathogenesis. Substantial research efforts using in vitro and in vivo models have provided valuable insights into the contribution of each mechanism in disease pathogenesis. However, conflicting evidence exists, and a unifying theory still lacks. Here, we provide an overview of the recently published literature on clinical, neuropathological and molecular features of C9-ALS/FTD. We highlight the supposed neuronal role of C9orf72 and the HRE pathogenic cascade, mainly focusing on the contribution of RNA foci and DPRs to neurodegeneration and discussing the several downstream mechanisms. We summarize the emerging biochemical and neuroimaging biomarkers, as well as the potential therapeutic approaches. Despite promising results, a specific disease-modifying treatment is still not available to date and greater insights into disease mechanisms may help in this direction.
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Affiliation(s)
- Delia Gagliardi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Gianluca Costamagna
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Michela Taiana
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Luca Andreoli
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Fabio Biella
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Margherita Bersani
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Nereo Bresolin
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy; Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Giacomo Pietro Comi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy; Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Stefania Corti
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy; Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy.
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24
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Lulé DE, Müller HP, Finsel J, Weydt P, Knehr A, Winroth I, Andersen P, Weishaupt J, Uttner I, Kassubek J, Ludolph AC. Deficits in verbal fluency in presymptomatic C9orf72 mutation gene carriers-a developmental disorder. J Neurol Neurosurg Psychiatry 2020; 91:1195-1200. [PMID: 32855285 PMCID: PMC7569387 DOI: 10.1136/jnnp-2020-323671] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/19/2020] [Accepted: 06/28/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND A mutation in C9orf72 constitute a cross-link between amyotrophic lateral sclerosis (ALS) and fronto-temporal dementia (FTD). At clinical manifestation, both patient groups may present with either cognitive impairment of predominantly behaviour or language (in FTD) or motor dysfunctions (in ALS). METHODS In total, 36 non-symptomatic mutation carriers from ALS or FTD families were examined, including 21 subjects with C9orf72 and 15 with SOD1 mutations. Data were compared with 91 age-matched, education-matched and gender-matched healthy subjects (56 were first-degree relatives from ALS or FTD families, 35 with no known family history of ALS/FTD). MRI scanning for diffusion tensor imaging was performed to map fractional anisotropy (FA). Subjects performed an extensive neuropsychological assessment to address verbal fluency, language, executive, memory and visuospatial function. Measurements were repeated after 12 months. RESULTS C9orf72 expansion carriers performed significantly worse in verbal fluency and non-verbal memory and presented with distinct alterations in structural white matter integrity indicated by lower FA values in inferior and orbitofrontal cortical areas compared with carriers of SOD1 mutations or healthy subjects. Loss of structural integrity was associated with decreased verbal fluency performance. White matter alterations and cognitive performance showed no changes over 12 months in all subjects. DISCUSSION Reduced verbal fluency performance seems to be a distinct clinical feature of C9orf72 carriers before symptomatic disease onset without evidence for change over time in our cohort. The results support the emerging hypothesis of a general disorder in development in addition to neurodegeneration in C9orf72 carriers.
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Affiliation(s)
- Dorothée E Lulé
- Department of Neurology, Neuropsychology, Ulm University, Ulm, Germany
| | | | - Julia Finsel
- Department of Neurology, University of Ulm, Ulm, Germany
| | - Patrick Weydt
- Department of Neurodegenerative Diseases and Gerontopsychiatry, University of Bonn, Bonn, Germany
| | - Antje Knehr
- Department of Neurology, University of Ulm, Ulm, Germany
| | | | | | | | - Ingo Uttner
- Department of Neurology, University of Ulm, Ulm, Germany
| | - Jan Kassubek
- Department of Neurology, University of Ulm, Ulm, Germany
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25
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Braems E, Swinnen B, Van Den Bosch L. C9orf72 loss-of-function: a trivial, stand-alone or additive mechanism in C9 ALS/FTD? Acta Neuropathol 2020; 140:625-643. [PMID: 32876811 PMCID: PMC7547039 DOI: 10.1007/s00401-020-02214-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 07/28/2020] [Accepted: 08/13/2020] [Indexed: 12/11/2022]
Abstract
A repeat expansion in C9orf72 is responsible for the characteristic neurodegeneration in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) in a still unresolved manner. Proposed mechanisms involve gain-of-functions, comprising RNA and protein toxicity, and loss-of-function of the C9orf72 gene. Their exact contribution is still inconclusive and reports regarding loss-of-function are rather inconsistent. Here, we review the function of the C9orf72 protein and its relevance in disease. We explore the potential link between reduced C9orf72 levels and disease phenotypes in postmortem, in vitro, and in vivo models. Moreover, the significance of loss-of-function in other non-coding repeat expansion diseases is used to clarify its contribution in C9orf72 ALS/FTD. In conclusion, with evidence pointing to a multiple-hit model, loss-of-function on itself seems to be insufficient to cause neurodegeneration in C9orf72 ALS/FTD.
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Affiliation(s)
- Elke Braems
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven-University of Leuven, 3000, Leuven, Belgium
- Laboratory of Neurobiology, Experimental Neurology, Center for Brain and Disease Research, VIB, Campus Gasthuisberg, O&N4, Herestraat 49, PB 602, 3000, Leuven, Belgium
| | - Bart Swinnen
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven-University of Leuven, 3000, Leuven, Belgium
- Laboratory of Neurobiology, Experimental Neurology, Center for Brain and Disease Research, VIB, Campus Gasthuisberg, O&N4, Herestraat 49, PB 602, 3000, Leuven, Belgium
- Department of Neurology, University Hospitals Leuven, 3000, Leuven, Belgium
| | - Ludo Van Den Bosch
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven-University of Leuven, 3000, Leuven, Belgium.
- Laboratory of Neurobiology, Experimental Neurology, Center for Brain and Disease Research, VIB, Campus Gasthuisberg, O&N4, Herestraat 49, PB 602, 3000, Leuven, Belgium.
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26
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Fortier G, Butti Z, Patten SA. Modelling C9orf72-Related Amyotrophic Lateral Sclerosis in Zebrafish. Biomedicines 2020; 8:E440. [PMID: 33096681 PMCID: PMC7589578 DOI: 10.3390/biomedicines8100440] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/16/2020] [Accepted: 10/17/2020] [Indexed: 12/12/2022] Open
Abstract
A hexanucleotide repeat expansion within the C9orf72 gene is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and its discovery has revolutionized our understanding of this devastating disease. Model systems are a valuable tool for studying ALS pathobiology and potential therapies. The zebrafish (Danio rerio) has particularly become a useful model organism to study neurological diseases, including ALS, due to high genetic and physiological homology to mammals, and sensitivity to various genetic and pharmacological manipulations. In this review we summarize the zebrafish models that have been used to study the pathology of C9orf72-related ALS. We discuss their value in providing mechanistic insights and their potential use for drug discovery.
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Affiliation(s)
- Gabrielle Fortier
- INRS-Centre Armand-Frappier Santé et Biotechnologie, Laval, QC H7V 1B7, Canada; (G.F.); (Z.B.)
| | - Zoé Butti
- INRS-Centre Armand-Frappier Santé et Biotechnologie, Laval, QC H7V 1B7, Canada; (G.F.); (Z.B.)
| | - Shunmoogum A. Patten
- INRS-Centre Armand-Frappier Santé et Biotechnologie, Laval, QC H7V 1B7, Canada; (G.F.); (Z.B.)
- Centre d’Excellence en Recherche sur les Maladies Orphelines—Fondation Courtois (CERMO-FC), Université du Québec à Montréal (UQAM), Montréal, QC H2X 3Y7, Canada
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27
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McEachin ZT, Parameswaran J, Raj N, Bassell GJ, Jiang J. RNA-mediated toxicity in C9orf72 ALS and FTD. Neurobiol Dis 2020; 145:105055. [PMID: 32829028 DOI: 10.1016/j.nbd.2020.105055] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/27/2020] [Accepted: 08/18/2020] [Indexed: 12/13/2022] Open
Abstract
A GGGGCC hexanucleotide repeat expansion in the first intron of C9orf72 is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. Compelling evidence suggests that gain of toxicity from the bidirectionally transcribed repeat expanded RNAs plays a central role in disease pathogenesis. Two potential mechanisms have been proposed including RNA-mediated toxicity and/or the production of toxic dipeptide repeat proteins. In this review, we focus on the role of RNA mediated toxicity in ALS/FTD caused by the C9orf72 mutation and discuss arguments for and against this mechanism. In addition, we summarize how G4C2 repeat RNAs can elicit toxicity and potential therapeutic strategies to mitigate RNA-mediated toxicity.
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Affiliation(s)
- Zachary T McEachin
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Laboratory for Translational Cell Biology, Emory University, Atlanta, GA 30322, USA.
| | | | - Nisha Raj
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Laboratory for Translational Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Laboratory for Translational Cell Biology, Emory University, Atlanta, GA 30322, USA; Department of Neurology, Emory University, Atlanta, GA 30322, USA
| | - Jie Jiang
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA.
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28
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Solomon DA, Mitchell JC, Salcher-Konrad MT, Vance CA, Mizielinska S. Review: Modelling the pathology and behaviour of frontotemporal dementia. Neuropathol Appl Neurobiol 2020; 45:58-80. [PMID: 30582188 DOI: 10.1111/nan.12536] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 12/16/2018] [Indexed: 12/11/2022]
Abstract
Frontotemporal dementia (FTD) encompasses a collection of clinically and pathologically diverse neurological disorders. Clinical features of behavioural and language dysfunction are associated with neurodegeneration, predominantly of frontal and temporal cortices. Over the past decade, there have been significant advances in the understanding of the genetic aetiology and neuropathology of FTD which have led to the creation of various disease models to investigate the molecular pathways that contribute to disease pathogenesis. The generation of in vivo models of FTD involves either targeting genes with known disease-causative mutations such as GRN and C9orf72 or genes encoding proteins that form the inclusions that characterize the disease pathologically, such as TDP-43 and FUS. This review provides a comprehensive summary of the different in vivo model systems used to understand pathomechanisms in FTD, with a focus on disease models which reproduce aspects of the wide-ranging behavioural phenotypes seen in people with FTD. We discuss the emerging disease pathways that have emerged from these in vivo models and how this has shaped our understanding of disease mechanisms underpinning FTD. We also discuss the challenges of modelling the complex clinical symptoms shown by people with FTD, the confounding overlap with features of motor neuron disease, and the drive to make models more disease-relevant. In summary, in vivo models can replicate many pathological and behavioural aspects of clinical FTD, but robust and thorough investigations utilizing shared features and variability between disease models will improve the disease-relevance of findings and thus better inform therapeutic development.
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Affiliation(s)
- D A Solomon
- UK Dementia Research Institute, King's College London, London, Camberwell, UK.,Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
| | - J C Mitchell
- Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
| | - M-T Salcher-Konrad
- Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
| | - C A Vance
- Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
| | - S Mizielinska
- UK Dementia Research Institute, King's College London, London, Camberwell, UK.,Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
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29
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Demy DL, Campanari ML, Munoz-Ruiz R, Durham HD, Gentil BJ, Kabashi E. Functional Characterization of Neurofilament Light Splicing and Misbalance in Zebrafish. Cells 2020; 9:E1238. [PMID: 32429483 PMCID: PMC7291018 DOI: 10.3390/cells9051238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/08/2020] [Accepted: 05/14/2020] [Indexed: 12/12/2022] Open
Abstract
Neurofilaments (NFs), a major cytoskeletal component of motor neurons, play a key role in the differentiation, establishment and maintenance of their morphology and mechanical strength. The de novo assembly of these neuronal intermediate filaments requires the presence of the neurofilament light subunit (NEFL), whose expression is reduced in motor neurons in amyotrophic lateral sclerosis (ALS). This study used zebrafish as a model to characterize the NEFL homologue neflb, which encodes two different isoforms via a splicing of the primary transcript (neflbE4 and neflbE3). In vivo imaging showed that neflb is crucial for proper neuronal development, and that disrupting the balance between its two isoforms specifically affects the NF assembly and motor axon growth, with resultant motor deficits. This equilibrium is also disrupted upon the partial depletion of TDP-43 (TAR DNA-binding protein 43), an RNA-binding protein encoded by the gene TARDBP that is mislocalized into cytoplasmic inclusions in ALS. The study supports the interaction of the NEFL expression and splicing with TDP-43 in a common pathway, both biologically and pathogenetically.
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Affiliation(s)
- Doris Lou Demy
- Institut Imagine, UMR-1163 INSERM et Université Paris Descartes, Hôpital Universitaire Necker-Enfants Malades, 24, boulevard du Montparnasse, 75015 Paris, France; (D.L.D.); (M.L.C.); (R.M.-R.)
- Sorbonne Universités Paris VI, UMR INSERM U 1127, CNRS 1127 UPMC, Institut du Cerveau et de la Moelle épinière—ICM, 75015 Paris, France
| | - Maria Letizia Campanari
- Institut Imagine, UMR-1163 INSERM et Université Paris Descartes, Hôpital Universitaire Necker-Enfants Malades, 24, boulevard du Montparnasse, 75015 Paris, France; (D.L.D.); (M.L.C.); (R.M.-R.)
- Sorbonne Universités Paris VI, UMR INSERM U 1127, CNRS 1127 UPMC, Institut du Cerveau et de la Moelle épinière—ICM, 75015 Paris, France
| | - Raphael Munoz-Ruiz
- Institut Imagine, UMR-1163 INSERM et Université Paris Descartes, Hôpital Universitaire Necker-Enfants Malades, 24, boulevard du Montparnasse, 75015 Paris, France; (D.L.D.); (M.L.C.); (R.M.-R.)
- Sorbonne Universités Paris VI, UMR INSERM U 1127, CNRS 1127 UPMC, Institut du Cerveau et de la Moelle épinière—ICM, 75015 Paris, France
| | - Heather D. Durham
- Department of Neurology and Neurosurgery and Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada; (H.D.D.); (B.J.G.)
| | - Benoit J. Gentil
- Department of Neurology and Neurosurgery and Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada; (H.D.D.); (B.J.G.)
- Department of Kinesiology and Physical Education McGill University, Montreal, QC H3A 2B4, Canada
| | - Edor Kabashi
- Institut Imagine, UMR-1163 INSERM et Université Paris Descartes, Hôpital Universitaire Necker-Enfants Malades, 24, boulevard du Montparnasse, 75015 Paris, France; (D.L.D.); (M.L.C.); (R.M.-R.)
- Sorbonne Universités Paris VI, UMR INSERM U 1127, CNRS 1127 UPMC, Institut du Cerveau et de la Moelle épinière—ICM, 75015 Paris, France
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Jiang J, Ravits J. Pathogenic Mechanisms and Therapy Development for C9orf72 Amyotrophic Lateral Sclerosis/Frontotemporal Dementia. Neurotherapeutics 2019; 16:1115-1132. [PMID: 31667754 PMCID: PMC6985338 DOI: 10.1007/s13311-019-00797-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In 2011, a hexanucleotide repeat expansion in the first intron of the C9orf72 gene was identified as the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The proposed disease mechanisms include loss of C9orf72 function and gain of toxicity from the bidirectionally transcribed repeat-containing RNAs. Over the last few years, substantial progress has been made to determine the contribution of loss and gain of function in disease pathogenesis. The extensive body of molecular, cellular, animal, and human neuropathological studies is conflicted, but the predominance of evidence favors gain of toxicity as the main pathogenic mechanism for C9orf72 repeat expansions. Alterations in several downstream cellular functions, such as nucleocytoplasmic transport and autophagy, are implicated. Exciting progress has also been made in therapy development targeting this mutation, such as by antisense oligonucleotide therapies targeting sense transcripts and small molecules targeting nucleocytoplasmic transport, and these are now in phase 1 clinical trials.
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Affiliation(s)
- Jie Jiang
- Department of Cell Biology, Emory University, Atlanta, GA, 30322, USA.
| | - John Ravits
- Department of Neurosciences, University of California at San Diego, La Jolla, CA, 92093, USA.
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Goodman LD, Bonini NM. Repeat-associated non-AUG (RAN) translation mechanisms are running into focus for GGGGCC-repeat associated ALS/FTD. Prog Neurobiol 2019; 183:101697. [PMID: 31550516 DOI: 10.1016/j.pneurobio.2019.101697] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 08/31/2019] [Accepted: 09/17/2019] [Indexed: 12/12/2022]
Abstract
Many human diseases are associated with the expansion of repeat sequences within the genes. It has become clear that expressed disease transcripts bearing such long repeats can undergo translation, even in the absence of a canonical AUG start codon. Termed "RAN translation" for repeat associated non-AUG translation, this process is becoming increasingly prominent as a contributor to these disorders. Here we discuss mechanisms and variables that impact translation of the repeat sequences associated with the C9orf72 gene. Expansions of a G4C2 repeat within intron 1 of this gene are associated with the motor neuron disease ALS and dementia FTD, which comprise a clinical and pathological spectrum. RAN translation of G4C2 repeat expansions has been studied in cells in culture (ex vivo) and in the fly in vivo. Cellular states that lead to RAN translation, like stress, may be critical contributors to disease progression. Greater elucidation of the mechanisms that impact this process and the factors contributing will lead to greater understanding of the repeat expansion diseases, to the potential development of novel approaches to therapeutics, and to a greater understanding of how these players impact biological processes in the absence of disease.
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Affiliation(s)
- Lindsey D Goodman
- Neuroscience Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nancy M Bonini
- Neuroscience Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Molecular Mechanisms of Neurodegeneration Related to C9orf72 Hexanucleotide Repeat Expansion. Behav Neurol 2019; 2019:2909168. [PMID: 30774737 PMCID: PMC6350563 DOI: 10.1155/2019/2909168] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 08/28/2018] [Accepted: 09/18/2018] [Indexed: 12/11/2022] Open
Abstract
Two clinically distinct diseases, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), have recently been classified as two extremes of the FTD/ALS spectrum. The neuropathological correlate of FTD is frontotemporal lobar degeneration (FTLD), characterized by tau-, TDP-43-, and FUS-immunoreactive neuronal inclusions. An earlier discovery that a hexanucleotide repeat expansion mutation in chromosome 9 open reading frame 72 (C9orf72) gene causes ALS and FTD established a special subtype of ALS and FTLD with TDP-43 pathology (C9FTD/ALS). Normal individuals carry 2–10 hexanucleotide GGGGCC repeats in the C9orf72 gene, while more than a few hundred repeats represent a risk for ALS and FTD. The proposed molecular mechanisms by which C9orf72 repeat expansions induce neurodegenerative changes are C9orf72 loss-of-function through haploinsufficiency, RNA toxic gain-of-function, and gain-of-function through the accumulation of toxic dipeptide repeat proteins. However, many more cellular processes are affected by pathological processes in C9FTD/ALS, including nucleocytoplasmic transport, RNA processing, normal function of nucleolus, formation of membraneless organelles, translation, ubiquitin proteasome system, Notch signalling pathway, granule transport, and normal function of TAR DNA-binding protein 43 (TDP-43). Although the exact molecular mechanisms through which C9orf72 repeat expansions account for neurodegeneration have not been elucidated, some potential therapeutics, such as antisense oligonucleotides targeting hexanucleotide GGGGCC repeats in mRNA, were successful in preclinical trials and are awaiting phase 1 clinical trials. In this review, we critically discuss each proposed mechanism and provide insight into the most recent studies aiming to elucidate the molecular underpinnings of C9FTD/ALS.
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