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Borrelli E, Bandello F, Boon CJF, Carelli V, Lenaers G, Reibaldi M, Sadda SR, Sadun AA, Sarraf D, Yu-Wai-Man P, Barboni P. Mitochondrial retinopathies and optic neuropathies: The impact of retinal imaging on modern understanding of pathogenesis, diagnosis, and management. Prog Retin Eye Res 2024; 101:101264. [PMID: 38703886 DOI: 10.1016/j.preteyeres.2024.101264] [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: 01/11/2024] [Revised: 03/18/2024] [Accepted: 04/26/2024] [Indexed: 05/06/2024]
Abstract
Advancements in ocular imaging have significantly broadened our comprehension of mitochondrial retinopathies and optic neuropathies by examining the structural and pathological aspects of the retina and optic nerve in these conditions. This article aims to review the prominent imaging characteristics associated with mitochondrial retinopathies and optic neuropathies, aiming to deepen our insight into their pathogenesis and clinical features. Preceding this exploration, the article provides a detailed overview of the crucial genetic and clinical features, which is essential for the proper interpretation of in vivo imaging. More importantly, we will provide a critical analysis on how these imaging modalities could serve as biomarkers for characterization and monitoring, as well as in guiding treatment decisions. However, these imaging methods have limitations, which will be discussed along with potential strategies to mitigate them. Lastly, the article will emphasize the potential advantages and future integration of imaging techniques in evaluating patients with mitochondrial eye disorders, considering the prospects of emerging gene therapies.
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Affiliation(s)
- Enrico Borrelli
- Department of Surgical Sciences, University of Turin, Turin, Italy; Department of Ophthalmology, "City of Health and Science" Hospital, Turin, Italy.
| | - Francesco Bandello
- Vita-Salute San Raffaele University, Milan, Italy; IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Camiel J F Boon
- Department of Ophthalmology, Amsterdam University Medical Centers, Amsterdam, the Netherlands; Department of Ophthalmology, Leiden University Medical Center, Leiden, the Netherlands
| | - Valerio Carelli
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy; IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | - Guy Lenaers
- Equipe MitoLab, Unité MitoVasc, INSERM U1083, Université d'Angers, 49933, Angers, France; Service de Neurologie, CHU d'Angers, 49100, Angers, France
| | - Michele Reibaldi
- Department of Surgical Sciences, University of Turin, Turin, Italy; Department of Ophthalmology, "City of Health and Science" Hospital, Turin, Italy
| | - Srinivas R Sadda
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Doheny Eye Institute, Los Angeles, CA, USA
| | - Alfredo A Sadun
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Doheny Eye Institute, Los Angeles, CA, USA
| | - David Sarraf
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Retinal Disorders and Ophthalmic Genetics Division, Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Patrick Yu-Wai-Man
- John van Geest Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Institute of Ophthalmology, University College London, London, UK
| | - Piero Barboni
- IRCCS San Raffaele Scientific Institute, Milan, Italy; Studio Oculistico d'Azeglio, Bologna, Italy.
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Garcia-Pardo ME, Simpson JC, O’Sullivan NC. An Automated Imaging-Based Screen for Genetic Modulators of ER Organisation in Cultured Human Cells. Cells 2024; 13:577. [PMID: 38607016 PMCID: PMC11011067 DOI: 10.3390/cells13070577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/08/2024] [Accepted: 03/23/2024] [Indexed: 04/13/2024] Open
Abstract
Hereditary spastic paraplegias (HSPs) are a heterogeneous group of mono-genetic inherited neurological disorders, whose primary manifestation is the disruption of the pyramidal system, observed as a progressive impaired gait and leg spasticity in patients. Despite the large list of genes linked to this group, which exceeds 80 loci, the number of cellular functions which the gene products engage is relatively limited, among which endoplasmic reticulum (ER) morphogenesis appears central. Mutations in genes encoding ER-shaping proteins are the most common cause of HSP, highlighting the importance of correct ER organisation for long motor neuron survival. However, a major bottleneck in the study of ER morphology is the current lack of quantitative methods, with most studies to date reporting, instead, on qualitative changes. Here, we describe and apply a quantitative image-based screen to identify genetic modifiers of ER organisation using a mammalian cell culture system. An analysis reveals significant quantitative changes in tubular ER and dense sheet ER organisation caused by the siRNA-mediated knockdown of HSP-causing genes ATL1 and RTN2. This screen constitutes the first attempt to examine ER distribution in cells in an automated and high-content manner and to detect genes which impact ER organisation.
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Affiliation(s)
- M. Elena Garcia-Pardo
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, 4 Dublin, Ireland
| | - Jeremy C. Simpson
- Cell Screening Laboratory, UCD School of Biology and Environmental Science, University College Dublin, 4 Dublin, Ireland
| | - Niamh C. O’Sullivan
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, 4 Dublin, Ireland
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Damiani D, Baggiani M, Della Vecchia S, Naef V, Santorelli FM. Pluripotent Stem Cells as a Preclinical Cellular Model for Studying Hereditary Spastic Paraplegias. Int J Mol Sci 2024; 25:2615. [PMID: 38473862 DOI: 10.3390/ijms25052615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 02/12/2024] [Accepted: 02/20/2024] [Indexed: 03/14/2024] Open
Abstract
Hereditary spastic paraplegias (HSPs) comprise a family of degenerative diseases mostly hitting descending axons of corticospinal neurons. Depending on the gene and mutation involved, the disease could present as a pure form with limb spasticity, or a complex form associated with cerebellar and/or cortical signs such as ataxia, dysarthria, epilepsy, and intellectual disability. The progressive nature of HSPs invariably leads patients to require walking canes or wheelchairs over time. Despite several attempts to ameliorate the life quality of patients that have been tested, current therapeutical approaches are just symptomatic, as no cure is available. Progress in research in the last two decades has identified a vast number of genes involved in HSP etiology, using cellular and animal models generated on purpose. Although unanimously considered invaluable tools for basic research, those systems are rarely predictive for the establishment of a therapeutic approach. The advent of induced pluripotent stem (iPS) cells allowed instead the direct study of morphological and molecular properties of the patient's affected neurons generated upon in vitro differentiation. In this review, we revisited all the present literature recently published regarding the use of iPS cells to differentiate HSP patient-specific neurons. Most studies have defined patient-derived neurons as a reliable model to faithfully mimic HSP in vitro, discovering original findings through immunological and -omics approaches, and providing a platform to screen novel or repurposed drugs. Thereby, one of the biggest hopes of current HSP research regards the use of patient-derived iPS cells to expand basic knowledge on the disease, while simultaneously establishing new therapeutic treatments for both generalized and personalized approaches in daily medical practice.
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Affiliation(s)
- Devid Damiani
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56128 Pisa, Italy
| | - Matteo Baggiani
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56128 Pisa, Italy
| | - Stefania Della Vecchia
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56128 Pisa, Italy
- Department of Neurosciences, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Valentina Naef
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56128 Pisa, Italy
| | - Filippo Maria Santorelli
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56128 Pisa, Italy
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Wali G, Li Y, Liyanage E, Kumar KR, Day ML, Sue CM. Pharmacological rescue of mitochondrial and neuronal defects in SPG7 hereditary spastic paraplegia patient neurons using high throughput assays. Front Neurosci 2023; 17:1231584. [PMID: 37766787 PMCID: PMC10520970 DOI: 10.3389/fnins.2023.1231584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 08/21/2023] [Indexed: 09/29/2023] Open
Abstract
SPG7 is the most common form of autosomal recessive hereditary spastic paraplegia (HSP). There is a lack of HSP-SPG7 human neuronal models to understand the disease mechanism and identify new drug treatments. We generated a human neuronal model of HSP-SPG7 using induced pluripotent stem (iPS) cell technology. We first generated iPS cells from three HSP-SPG7 patients carrying different disease-causing variants and three healthy controls. The iPS cells were differentiated to form neural progenitor cells (NPCs) and then from NPCs to mature cortical neurons. Mitochondrial and neuronal defects were measured using a high throughout imaging and analysis-based assay in live cells. Our results show that compared to control NPCs, patient NPCs had aberrant mitochondrial morphology with increased mitochondrial size and reduced membrane potential. Patient NPCs develop to form mature cortical neurons with amplified mitochondrial morphology and functional defects along with defects in neuron morphology - reduced neurite complexity and length, reduced synaptic gene, protein expression and activity, reduced viability and increased axonal degeneration. Treatment of patient neurons with Bz-423, a mitochondria permeability pore regulator, restored the mitochondrial and neurite morphological defects and mitochondrial membrane potential back to control neuron levels and rescued the low viability and increased degeneration in patient neurons. This study establishes a direct link between mitochondrial and neuronal defects in HSP-SPG7 patient neurons. We present a strategy for testing mitochondrial targeting drugs to rescue neuronal defects in HSP-SPG7 patient neurons.
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Affiliation(s)
- Gautam Wali
- Neuroscience Research Australia, Sydney, NSW, Australia
- Kolling Institute for Medical Research, University of Sydney, NSW, Australia
| | - Yan Li
- Neuroscience Research Australia, Sydney, NSW, Australia
- Kolling Institute for Medical Research, University of Sydney, NSW, Australia
- University of New South Wales, Sydney, NSW, Australia
| | - Erandhi Liyanage
- Neuroscience Research Australia, Sydney, NSW, Australia
- Kolling Institute for Medical Research, University of Sydney, NSW, Australia
- University of New South Wales, Sydney, NSW, Australia
| | - Kishore R. Kumar
- University of New South Wales, Sydney, NSW, Australia
- Translational Neurogenomics Group, Molecular Medicine Laboratory and Department of Neurology, Concord Repatriation General Hospital, Concord Clinical School, University of Sydney, Concord, NSW, Australia
- Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
| | - Margot L. Day
- School of Medical Science, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Carolyn M. Sue
- Neuroscience Research Australia, Sydney, NSW, Australia
- Kolling Institute for Medical Research, University of Sydney, NSW, Australia
- University of New South Wales, Sydney, NSW, Australia
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5
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Mou Y, Nandi G, Mukte S, Chai E, Chen Z, Nielsen JE, Nielsen TT, Criscuolo C, Blackstone C, Fraidakis MJ, Li XJ. Chenodeoxycholic acid rescues axonal degeneration in induced pluripotent stem cell-derived neurons from spastic paraplegia type 5 and cerebrotendinous xanthomatosis patients. Orphanet J Rare Dis 2023; 18:72. [PMID: 37024986 PMCID: PMC10080795 DOI: 10.1186/s13023-023-02666-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 03/11/2023] [Indexed: 04/08/2023] Open
Abstract
BACKGROUND Biallelic mutations in CYP27A1 and CYP7B1, two critical genes regulating cholesterol and bile acid metabolism, cause cerebrotendinous xanthomatosis (CTX) and hereditary spastic paraplegia type 5 (SPG5), respectively. These rare diseases are characterized by progressive degeneration of corticospinal motor neuron axons, yet the underlying pathogenic mechanisms and strategies to mitigate axonal degeneration remain elusive. METHODS To generate induced pluripotent stem cell (iPSC)-based models for CTX and SPG5, we reprogrammed patient skin fibroblasts into iPSCs by transducing fibroblast cells with episomal vectors containing pluripotency factors. These patient-specific iPSCs, as well as control iPSCs, were differentiated into cortical projection neurons (PNs) and examined for biochemical alterations and disease-related phenotypes. RESULTS CTX and SPG5 patient iPSC-derived cortical PNs recapitulated several disease-specific biochemical changes and axonal defects of both diseases. Notably, the bile acid chenodeoxycholic acid (CDCA) effectively mitigated the biochemical alterations and rescued axonal degeneration in patient iPSC-derived neurons. To further examine underlying disease mechanisms, we developed CYP7B1 knockout human embryonic stem cell (hESC) lines using CRISPR-cas9-mediated gene editing and, following differentiation, examined hESC-derived cortical PNs. Knockout of CYP7B1 resulted in similar axonal vesiculation and degeneration in human cortical PN axons, confirming a cause-effect relationship between gene deficiency and axonal degeneration. Interestingly, CYP7B1 deficiency led to impaired neurofilament expression and organization as well as axonal degeneration, which could be rescued with CDCA, establishing a new disease mechanism and therapeutic target to mitigate axonal degeneration. CONCLUSIONS Our data demonstrate disease-specific lipid disturbances and axonopathy mechanisms in human pluripotent stem cell-based neuronal models of CTX and SPG5 and identify CDCA, an established treatment of CTX, as a potential pharmacotherapy for SPG5. We propose this novel treatment strategy to rescue axonal degeneration in SPG5, a currently incurable condition.
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Affiliation(s)
- Yongchao Mou
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL, 61107, USA
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Ghata Nandi
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL, 61107, USA
| | - Sukhada Mukte
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL, 61107, USA
| | - Eric Chai
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL, 61107, USA
| | - Zhenyu Chen
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL, 61107, USA
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Jorgen E Nielsen
- Neurogenetics Clinic & Research Laboratory, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Troels T Nielsen
- Neurogenetics Clinic & Research Laboratory, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Chiara Criscuolo
- Department of Neuroscience, Reproductive Sciences and Odontostomatology, Federico II University, Naples, Italy
| | - Craig Blackstone
- Movement Disorders Division, Department of Neurology, Massachusetts General Hospital, Boston, MA, 02114, USA
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Charlestown, Boston, MA, 02129, USA
| | - Matthew J Fraidakis
- Rare Neurological Diseases Unit, Department of Neurology, Attikon University Hospital, Medical School of the University of Athens, Athens, Greece
| | - Xue-Jun Li
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL, 61107, USA.
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, 60607, USA.
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Jin P, Wang Y, Nian N, Wang GQ, Fu XM. Hereditary spastic paraplegia (SPG 48) with deafness and azoospermia: A case report. Front Neurol 2023; 14:1156100. [PMID: 37077568 PMCID: PMC10106626 DOI: 10.3389/fneur.2023.1156100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 03/21/2023] [Indexed: 04/05/2023] Open
Abstract
Hereditary spastic paraplegias (HSP) are inherited neurodegenerative disorders characterized by progressive paraplegia and spasticity in the lower limbs. SPG48 represents a rare genotype characterized by mutations in AP5Z1, a gene playing a role in intracellular membrane trafficking. This study describes a case of a 53-year-old male patient with SPG48 presenting spastic paraplegia, infertility, hearing impairment, cognitive abnormalities and peripheral neuropathy. The Sanger sequencing revealed a homozygous deletion in the chr 7:4785904-4786677 region causing a premature stop codon in exon 10. The patient's brother was heterozygous for the mutation. The brain magnetic resonance imaging found a mild brain atrophy and white matter lesions. In the analysis of the auditory thresholds, we found a significant hearing decrease in both ears.
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Affiliation(s)
- Ping Jin
- Department of Neurology, The Affiliated Hospital of Institute of Neurology, Anhui University of Chinese Medicine, Hefei, China
| | - Yu Wang
- Department of Neurology, The Affiliated Hospital of Institute of Neurology, Anhui University of Chinese Medicine, Hefei, China
| | - Na Nian
- Department of Neurology, The Affiliated Hospital of Institute of Neurology, Anhui University of Chinese Medicine, Hefei, China
| | - Gong-Qiang Wang
- Department of Neurology, The Affiliated Hospital of Institute of Neurology, Anhui University of Chinese Medicine, Hefei, China
| | - Xiao-Ming Fu
- Department of Neurology, The Affiliated Hospital of Institute of Neurology, Anhui University of Chinese Medicine, Hefei, China
- Institute of Neurology, Anhui University of Chinese, Hefei, China
- *Correspondence: Xiao-Ming Fu
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7
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Suzuki N, Nishiyama A, Warita H, Aoki M. Genetics of amyotrophic lateral sclerosis: seeking therapeutic targets in the era of gene therapy. J Hum Genet 2023; 68:131-152. [PMID: 35691950 PMCID: PMC9968660 DOI: 10.1038/s10038-022-01055-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/17/2022] [Accepted: 05/29/2022] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is an intractable disease that causes respiratory failure leading to mortality. The main locus of ALS is motor neurons. The success of antisense oligonucleotide (ASO) therapy in spinal muscular atrophy (SMA), a motor neuron disease, has triggered a paradigm shift in developing ALS therapies. The causative genes of ALS and disease-modifying genes, including those of sporadic ALS, have been identified one after another. Thus, the freedom of target choice for gene therapy has expanded by ASO strategy, leading to new avenues for therapeutic development. Tofersen for superoxide dismutase 1 (SOD1) was a pioneer in developing ASO for ALS. Improving protocols and devising early interventions for the disease are vital. In this review, we updated the knowledge of causative genes in ALS. We summarized the genetic mutations identified in familial ALS and their clinical features, focusing on SOD1, fused in sarcoma (FUS), and transacting response DNA-binding protein. The frequency of the C9ORF72 mutation is low in Japan, unlike in Europe and the United States, while SOD1 and FUS are more common, indicating that the target mutations for gene therapy vary by ethnicity. A genome-wide association study has revealed disease-modifying genes, which could be the novel target of gene therapy. The current status and prospects of gene therapy development were discussed, including ethical issues. Furthermore, we discussed the potential of axonal pathology as new therapeutic targets of ALS from the perspective of early intervention, including intra-axonal transcription factors, neuromuscular junction disconnection, dysregulated local translation, abnormal protein degradation, mitochondrial pathology, impaired axonal transport, aberrant cytoskeleton, and axon branching. We simultaneously discuss important pathological states of cell bodies: persistent stress granules, disrupted nucleocytoplasmic transport, and cryptic splicing. The development of gene therapy based on the elucidation of disease-modifying genes and early intervention in molecular pathology is expected to become an important therapeutic strategy in ALS.
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Affiliation(s)
- Naoki Suzuki
- Department of Neurology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan.
| | - Ayumi Nishiyama
- Department of Neurology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan
| | - Hitoshi Warita
- Department of Neurology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan
| | - Masashi Aoki
- Department of Neurology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan.
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Synofzik M, Rugarli E, Reid E, Schüle R. Ataxia and spastic paraplegia in mitochondrial disease. HANDBOOK OF CLINICAL NEUROLOGY 2023; 194:79-98. [PMID: 36813322 DOI: 10.1016/b978-0-12-821751-1.00009-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Degenerative ataxias and hereditary spastic paraplegias (HSPs) form a continuous, often overlapping disease spectrum sharing not only phenotypic features and underlying genes, but also cellular pathways and disease mechanisms. Mitochondrial metabolism presents a major molecular theme underlying both multiple ataxias and HSPs, thus indicating a heightened vulnerability of Purkinje cells, spinocerebellar tracts, and motor neurons to mitochondrial dysfunction, which is of particular interest for translational approaches. Mitochondrial dysfunction might be the primary (upstream) or secondary (downstream) result of a genetic defect, with underlying genetic defects in nuclear-encoded genes being much more frequent than in mtDNA genes in both, ataxias and HSPs. Here, we outline the substantial number of ataxias, spastic ataxias and HSPs caused by mutated genes implicated in (primary or secondary) mitochondrial dysfunction, highlighting several key "mitochondrial" ataxias and HSPs which are of particular interest for their frequency, pathogenesis and translational opportunities. We then showcase prototypic mitochondrial mechanisms by which disruption of these ataxia and HSP genes contributes to Purkinje cells or corticospinal neuron dysfunction, thus elucidating hypotheses on Purkinje cells and corticospinal neuron vulnerability to mitochondrial dysfunction.
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Affiliation(s)
- Matthis Synofzik
- Department of Neurodegenerative Diseases, Center for Neurology & Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE), Tübingen, Germany.
| | - Elena Rugarli
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, and Center for Molecular Medicine, University of Cologne, Cologne, Germany
| | - Evan Reid
- Cambridge Institute for Medical Research and Department of Medical Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Rebecca Schüle
- Department of Neurodegenerative Diseases, Center for Neurology & Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE), Tübingen, Germany
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9
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Neurometabolic Dysfunction in SPG11 Hereditary Spastic Paraplegia. Nutrients 2022; 14:nu14224803. [PMID: 36432490 PMCID: PMC9693816 DOI: 10.3390/nu14224803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Pathogenic variants in SPG11 cause the most common autosomal recessive complicated hereditary spastic paraplegia. Besides the prototypical combination of spastic paraplegia with a thin corpus callosum, obesity has increasingly been reported in this multisystem neurodegenerative disease. However, a detailed analysis of the metabolic state is lacking. METHODS In order to characterize metabolic alterations, a cross-sectional analysis was performed comparing SPG11 patients (n = 16) and matched healthy controls (n = 16). We quantified anthropometric parameters, body composition as determined by bioimpedance spectroscopy, and serum metabolic biomarkers, and we measured hypothalamic volume by high-field MRI. RESULTS Compared to healthy controls, SPG11 patients exhibited profound changes in body composition, characterized by increased fat tissue index, decreased lean tissue index, and decreased muscle mass. The presence of lymphedema correlated with increased extracellular fluid. The serum levels of the adipokines leptin, resistin, and progranulin were significantly altered in SPG11 while adiponectin and C1q/TNF-related protein 3 (CTRP-3) were unchanged. MRI volumetry revealed a decreased hypothalamic volume in SPG11 patients. CONCLUSIONS Body composition, adipokine levels, and hypothalamic volume are altered in SPG11. Our data indicate a link between obesity and hypothalamic neurodegeneration in SPG11 and imply that specific metabolic interventions may prevent obesity despite severely impaired mobility in SPG11.
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10
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Tábara LC, Al-Salmi F, Maroofian R, Al-Futaisi AM, Al-Murshedi F, Kennedy J, Day JO, Courtin T, Al-Khayat A, Galedari H, Mazaheri N, Protasoni M, Johnson M, Leslie JS, Salter CG, Rawlins LE, Fasham J, Al-Maawali A, Voutsina N, Charles P, Harrold L, Keren B, Kunji ERS, Vona B, Jelodar G, Sedaghat A, Shariati G, Houlden H, Crosby AH, Prudent J, Baple EL. TMEM63C mutations cause mitochondrial morphology defects and underlie hereditary spastic paraplegia. Brain 2022; 145:3095-3107. [PMID: 35718349 PMCID: PMC9473353 DOI: 10.1093/brain/awac123] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 02/10/2022] [Accepted: 03/13/2022] [Indexed: 02/02/2023] Open
Abstract
The hereditary spastic paraplegias (HSP) are among the most genetically diverse of all Mendelian disorders. They comprise a large group of neurodegenerative diseases that may be divided into 'pure HSP' in forms of the disease primarily entailing progressive lower-limb weakness and spasticity, and 'complex HSP' when these features are accompanied by other neurological (or non-neurological) clinical signs. Here, we identified biallelic variants in the transmembrane protein 63C (TMEM63C) gene, encoding a predicted osmosensitive calcium-permeable cation channel, in individuals with hereditary spastic paraplegias associated with mild intellectual disability in some, but not all cases. Biochemical and microscopy analyses revealed that TMEM63C is an endoplasmic reticulum-localized protein, which is particularly enriched at mitochondria-endoplasmic reticulum contact sites. Functional in cellula studies indicate a role for TMEM63C in regulating both endoplasmic reticulum and mitochondrial morphologies. Together, these findings identify autosomal recessive TMEM63C variants as a cause of pure and complex HSP and add to the growing evidence of a fundamental pathomolecular role of perturbed mitochondrial-endoplasmic reticulum dynamics in motor neurone degenerative diseases.
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Affiliation(s)
- Luis Carlos Tábara
- Medical Research Council Mitochondrial Biology Unit, University of
Cambridge, Cambridge CB2 0XY, UK
| | - Fatema Al-Salmi
- Level 4, RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford)
NHS Foundation Trust, University of Exeter Medical School,
Exeter EX2 5DW, UK
| | - Reza Maroofian
- UCL Queen Square Institute of Neurology, University College
London, London WC1E 6BT, UK
| | - Amna Mohammed Al-Futaisi
- Genetic and Developmental Medicine Clinic, Department of Genetics, College
of Medicine and Health Sciences, Sultan Qaboos University Hospital,
Muscat 123, Oman
| | - Fathiya Al-Murshedi
- Genetic and Developmental Medicine Clinic, Department of Genetics, College
of Medicine and Health Sciences, Sultan Qaboos University Hospital,
Muscat 123, Oman
| | - Joanna Kennedy
- Level 4, RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford)
NHS Foundation Trust, University of Exeter Medical School,
Exeter EX2 5DW, UK
- Clinical Genetics, University Hospitals Bristol,
Bristol BS2 8EG, UK
| | - Jacob O Day
- Level 4, RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford)
NHS Foundation Trust, University of Exeter Medical School,
Exeter EX2 5DW, UK
- Faculty of Health, University of Plymouth,
Plymouth PL4 8AA, UK
| | - Thomas Courtin
- Département de génétique, Hôpital Pitié-Salpêtrière, Assistance
Publique-Hôpitaux de Paris, 75019 Paris, Sorbonne
Université, France
| | - Aisha Al-Khayat
- Department of Biology, College of Science, Sultan Qaboos
University, Muscat, Oman
| | - Hamid Galedari
- Department of Genetics, Faculty of Science, Shahid Chamran University of
Ahvaz, Ahvaz, Iran
| | - Neda Mazaheri
- Department of Genetics, Faculty of Science, Shahid Chamran University of
Ahvaz, Ahvaz, Iran
| | - Margherita Protasoni
- Medical Research Council Mitochondrial Biology Unit, University of
Cambridge, Cambridge CB2 0XY, UK
| | - Mark Johnson
- Medical Research Council Mitochondrial Biology Unit, University of
Cambridge, Cambridge CB2 0XY, UK
| | - Joseph S Leslie
- Level 4, RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford)
NHS Foundation Trust, University of Exeter Medical School,
Exeter EX2 5DW, UK
| | - Claire G Salter
- Level 4, RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford)
NHS Foundation Trust, University of Exeter Medical School,
Exeter EX2 5DW, UK
| | - Lettie E Rawlins
- Level 4, RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford)
NHS Foundation Trust, University of Exeter Medical School,
Exeter EX2 5DW, UK
- Peninsula Clinical Genetics Service, Royal Devon and Exeter Hospital
(Heavitree), Exeter EX1 2ED, UK
| | - James Fasham
- Level 4, RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford)
NHS Foundation Trust, University of Exeter Medical School,
Exeter EX2 5DW, UK
- Peninsula Clinical Genetics Service, Royal Devon and Exeter Hospital
(Heavitree), Exeter EX1 2ED, UK
| | - Almundher Al-Maawali
- Genetic and Developmental Medicine Clinic, Department of Genetics, College
of Medicine and Health Sciences, Sultan Qaboos University Hospital,
Muscat 123, Oman
| | - Nikol Voutsina
- Level 4, RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford)
NHS Foundation Trust, University of Exeter Medical School,
Exeter EX2 5DW, UK
| | - Perrine Charles
- Département de génétique, Hôpital Pitié-Salpêtrière, Assistance
Publique-Hôpitaux de Paris, 75019 Paris, Sorbonne
Université, France
| | - Laura Harrold
- Level 4, RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford)
NHS Foundation Trust, University of Exeter Medical School,
Exeter EX2 5DW, UK
| | - Boris Keren
- Département de génétique, Hôpital Pitié-Salpêtrière, Assistance
Publique-Hôpitaux de Paris, 75019 Paris, Sorbonne
Université, France
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit, University of
Cambridge, Cambridge CB2 0XY, UK
| | - Barbara Vona
- Department of Otolaryngology-Head and Neck Surgery, Tübingen Hearing
Research Centre, Eberhard Karls University Tübingen,
Tübingen, Germany
| | - Gholamreza Jelodar
- Pediatric Neurology, Ahvaz Jundishapur University of Medical
Sciences, Ahvaz, Iran
| | - Alireza Sedaghat
- Health Research Institute, Diabetes Research Center, Ahvaz Jundishapur
University of Medical Sciences, Ahvaz, Iran
| | - Gholamreza Shariati
- Department of Medical Genetic, Faculty of Medicine, Ahvaz Jundishapur,
University of Medical Sciences, Ahvaz, Iran
| | - Henry Houlden
- UCL Queen Square Institute of Neurology, University College
London, London WC1E 6BT, UK
| | - Andrew H Crosby
- Level 4, RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford)
NHS Foundation Trust, University of Exeter Medical School,
Exeter EX2 5DW, UK
| | - Julien Prudent
- Medical Research Council Mitochondrial Biology Unit, University of
Cambridge, Cambridge CB2 0XY, UK
| | - Emma L Baple
- Level 4, RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford)
NHS Foundation Trust, University of Exeter Medical School,
Exeter EX2 5DW, UK
- Peninsula Clinical Genetics Service, Royal Devon and Exeter Hospital
(Heavitree), Exeter EX1 2ED, UK
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11
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Cytosolic sequestration of spatacsin by Protein Kinase A and 14-3-3 proteins. Neurobiol Dis 2022; 174:105858. [PMID: 36096339 DOI: 10.1016/j.nbd.2022.105858] [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: 05/23/2022] [Revised: 09/06/2022] [Accepted: 09/08/2022] [Indexed: 11/23/2022] Open
Abstract
Mutations in SPG11, encoding spatacsin, constitute the major cause of autosomal recessive Hereditary Spastic Paraplegia (HSP) with thinning of the corpus callosum. Previous studies showed that spatacsin orchestrates cellular traffic events through the formation of a coat-like complex and its loss of function results in lysosomal and axonal transport impairments. However, the upstream mechanisms that regulate spatacsin trafficking are unknown. Here, using proteomics and CRISPR/Cas9-mediated tagging of endogenous spatacsin, we identified a subset of 14-3-3 proteins as physiological interactors of spatacsin. The interaction is modulated by Protein Kinase A (PKA)-dependent phosphorylation of spatacsin at Ser1955, which initiates spatacsin trafficking from the plasma membrane to the intracellular space. Our study provides novel insight in understanding spatacsin physio-pathological roles with mechanistic dissection of its associated pathways.
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12
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Mitochondrial Quality and Quantity Control: Mitophagy Is a Potential Therapeutic Target for Ischemic Stroke. Mol Neurobiol 2022; 59:3110-3123. [PMID: 35266113 DOI: 10.1007/s12035-022-02795-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 03/05/2022] [Indexed: 02/07/2023]
Abstract
Ischemic stroke is a cerebrovascular disease with high mortality and disability, which seriously affects the health and lives of people around the world. Effective treatment for ischemic stroke has been limited by its complex pathological mechanisms. Increasing evidence has indicated that mitochondrial dysfunction plays an essential role in the occurrence, development, and pathological processes of ischemic stroke. Therefore, strict control of the quality and quantity of mitochondria via mitochondrial fission and fusion as well as mitophagy is beneficial to the survival and normal function maintenance of neurons. Under certain circumstances, excessive mitophagy also could induce cell death. This review discusses the dynamic changes and double-edged roles of mitochondria and related signaling pathways of mitophagy in the pathophysiology of ischemic stroke. Furthermore, we focus on the possibility of modulating mitophagy as a potential therapy for the prevention and prognosis of ischemic stroke. Notably, we reviewed recent advances in the studies of natural compounds, which could modulate mitophagy and exhibit neuroprotective effects, and discussed their potential application in the treatment of ischemic stroke.
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13
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Chen Z, Chai E, Mou Y, Roda RH, Blackstone C, Li XJ. Inhibiting mitochondrial fission rescues degeneration in hereditary spastic paraplegia neurons. Brain 2022; 145:4016-4031. [PMID: 35026838 DOI: 10.1093/brain/awab488] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 11/04/2021] [Accepted: 12/03/2021] [Indexed: 11/14/2022] Open
Abstract
Abstract
Hereditary spastic paraplegias (HSPs) are characterized by lower limb spasticity resulting from degeneration of long corticospinal axons. SPG11 is one of the most common autosomal recessive HSPs, and the SPG11 protein spatacsin forms a complex with the SPG15 protein spastizin and heterotetrameric AP5 adaptor protein complex, which includes the SPG48 protein AP5Z1. Using the integration-free episomal method, we established SPG11 patient-specific induced pluripotent stem cells (iPSCs) from patient fibroblasts. We differentiated SPG11 iPSCs, as well as SPG48 iPSCs previously established, into cortical projection neurons (PNs) and examined protective effects by targeting mitochondrial dynamics using P110, a peptide that selectively inhibits mitochondrial fission GTPase Drp1. P110 treatment mitigates mitochondrial fragmentation, improves mitochondrial motility, and restores mitochondrial health and ATP levels in SPG11 and SPG48 neurons. Neurofilament (NF) aggregations are increased in SPG11 and SPG48 axons, and these are also suppressed by P110. Similarly, P110 mitigates NF disruption in both SPG11 and SPG48 knockdown cortical PNs, confirming the contribution of HSP gene deficiency to subsequent NF and mitochondrial defects. Strikingly, NF aggregations in SPG11 and SPG48 deficient neurons double stain with ubiquitin and autophagy related proteins, resembling the pathological hallmark observed in SPG11 autopsy brain sections. To confirm the cause-effect relationship between the SPG11 mutations and disease phenotypes, we knocked-in SPG11 disease mutations to human embryonic stem cells (hESCs) and differentiated these stem cells into cortical PNs. Reduced ATP levels and accumulated NF aggregations along axons are observed, and both are mitigated by P110. Furthermore, rescue experiment with expression of wildtype SPG11 in cortical PNs derived from both SPG11 patient iPSCs and SPG11 disease mutation knock-in hESCs leads to rescue of mitochondrial dysfunction and NF aggregations in these SPG11 neurons. Finally, in SPG11 and SPG48 long-term cultures, increased release of phosphoNF-H, a biomarker for nerve degeneration, is significantly reduced by inhibiting mitochondrial fission pharmacologically using P110 and genetically using Drp1 shRNA. Taken together, our results demonstrate that impaired mitochondrial dynamics underlie both cytoskeletal disorganization and axonal degeneration in SPG11 and SPG48 neurons, highlighting the importance of targeting these pathologies therapeutically.
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Affiliation(s)
- Zhenyu Chen
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL 61107, USA
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Eric Chai
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL 61107, USA
| | - Yongchao Mou
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL 61107, USA
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Ricardo H. Roda
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- Department of Neurology, Johns Hopkins University of Medicine, Baltimore, MD 21205, USA
| | - Craig Blackstone
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- Movement Disorders Division, Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Xue-Jun Li
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL 61107, USA
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
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14
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Shin J, Nile A, Oh JW. Role of adaptin protein complexes in intracellular trafficking and their impact on diseases. Bioengineered 2021; 12:8259-8278. [PMID: 34565296 PMCID: PMC8806629 DOI: 10.1080/21655979.2021.1982846] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 09/15/2021] [Accepted: 09/15/2021] [Indexed: 02/07/2023] Open
Abstract
Adaptin proteins (APs) play a crucial role in intracellular cell trafficking. The 'classical' role of APs is carried out by AP1‒3, which bind to clathrin, cargo, and accessory proteins. Accordingly, AP1-3 are crucial for both vesicle formation and sorting. All APs consist of four subunits that are indispensable for their functions. In fact, based on studies using cells, model organism knockdown/knock-out, and human variants, each subunit plays crucial roles and contributes to the specificity of each AP. These studies also revealed that the sorting and intracellular trafficking function of AP can exert varying effects on pathology by controlling features such as cell development, signal transduction related to the apoptosis and proliferation pathways in cancer cells, organelle integrity, receptor presentation, and viral infection. Although the roles and functions of AP1‒3 are relatively well studied, the functions of the less abundant and more recently identified APs, AP4 and AP5, are still to be investigated. Further studies on these APs may enable a better understanding and targeting of specific diseases.APs known or suggested locations and functions.
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Affiliation(s)
- Juhyun Shin
- Department of Stem Cell and Regenerative Biotechnology and Animal Resources Research Center, Konkuk University, Seoul, Republic of Korea
| | - Arti Nile
- Department of Stem Cell and Regenerative Biotechnology and Animal Resources Research Center, Konkuk University, Seoul, Republic of Korea
| | - Jae-Wook Oh
- Department of Stem Cell and Regenerative Biotechnology and Animal Resources Research Center, Konkuk University, Seoul, Republic of Korea
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15
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Mou Y, Dein J, Chen Z, Jagdale M, Li XJ. MFN2 Deficiency Impairs Mitochondrial Transport and Downregulates Motor Protein Expression in Human Spinal Motor Neurons. Front Mol Neurosci 2021; 14:727552. [PMID: 34602978 PMCID: PMC8482798 DOI: 10.3389/fnmol.2021.727552] [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: 06/18/2021] [Accepted: 08/26/2021] [Indexed: 11/13/2022] Open
Abstract
Charcot-Marie-Tooth (CMT) disease is one of the most common genetically inherited neurological disorders and CMT type 2A (CMT 2A) is caused by dominant mutations in the mitofusin-2 (MFN2) gene. MFN2 is located in the outer mitochondrial membrane and is a mediator of mitochondrial fusion, with an essential role in maintaining normal neuronal functions. Although loss of MFN2 induces axonal neuropathy, the detailed mechanism by which MFN2 deficiency results in axonal degeneration of human spinal motor neurons remains largely unknown. In this study, we generated MFN2-knockdown human embryonic stem cell (hESC) lines using lentivirus expressing MFN2 short hairpin RNA (shRNA). Using these hESC lines, we found that MFN2 loss did not affect spinal motor neuron differentiation from hESCs but resulted in mitochondrial fragmentation and dysfunction as determined by live-cell imaging. Notably, MFN2-knockodwn spinal motor neurons exhibited CMT2A disease-related phenotypes, including extensive perikaryal inclusions of phosphorylated neurofilament heavy chain (pNfH), frequent axonal swellings, and increased pNfH levels in long-term cultures. Importantly, MFN2 deficit impaired anterograde and retrograde mitochondrial transport within axons, and reduced the mRNA and protein levels of kinesin and dynein, indicating the interfered motor protein expression induced by MFN2 deficiency. Our results reveal that MFN2 knockdown induced axonal degeneration of spinal motor neurons and defects in mitochondrial morphology and function. The impaired mitochondrial transport in MFN2-knockdown spinal motor neurons is mediated, at least partially, by the altered motor proteins, providing potential therapeutic targets for rescuing axonal degeneration of spinal motor neurons in CMT2A disease.
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Affiliation(s)
- Yongchao Mou
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL, United States.,Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Joshua Dein
- MD Program, University of Illinois College of Medicine Rockford, Rockford, IL, United States
| | - Zhenyu Chen
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL, United States.,Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Mrunali Jagdale
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL, United States.,Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Xue-Jun Li
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL, United States.,Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
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16
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Güner F, Pozner T, Krach F, Prots I, Loskarn S, Schlötzer-Schrehardt U, Winkler J, Winner B, Regensburger M. Axon-Specific Mitochondrial Pathology in SPG11 Alpha Motor Neurons. Front Neurosci 2021; 15:680572. [PMID: 34326717 PMCID: PMC8314181 DOI: 10.3389/fnins.2021.680572] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 06/14/2021] [Indexed: 11/13/2022] Open
Abstract
Pathogenic variants in SPG11 are the most frequent cause of autosomal recessive complicated hereditary spastic paraplegia (HSP). In addition to spastic paraplegia caused by corticospinal degeneration, most patients are significantly affected by progressive weakness and muscle wasting due to alpha motor neuron (MN) degeneration. Mitochondria play a crucial role in neuronal health, and mitochondrial deficits were reported in other types of HSPs. To investigate whether mitochondrial pathology is present in SPG11, we differentiated MNs from induced pluripotent stem cells derived from SPG11 patients and controls. MN derived from human embryonic stem cells and an isogenic SPG11 knockout line were also included in the study. Morphological analysis of mitochondria in the MN soma versus neurites revealed specific alterations of mitochondrial morphology within SPG11 neurites, but not within the soma. In addition, impaired mitochondrial membrane potential was indicative of mitochondrial dysfunction. Moreover, we reveal neuritic aggregates further supporting neurite pathology in SPG11. Correspondingly, using a microfluidic-based MN culture system, we demonstrate that axonal mitochondrial transport was significantly impaired in SPG11. Overall, our data demonstrate that alterations in morphology, function, and transport of mitochondria are an important feature of axonal dysfunction in SPG11 MNs.
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Affiliation(s)
- Fabian Güner
- Department of Stem Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Tatyana Pozner
- Department of Stem Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Florian Krach
- Department of Stem Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Iryna Prots
- Department of Stem Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Sandra Loskarn
- Department of Stem Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | | | - Jürgen Winkler
- Department of Molecular Neurology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Center for Rare Diseases Erlangen, University Hospital Erlangen, Erlangen, Germany
| | - Beate Winner
- Department of Stem Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Center for Rare Diseases Erlangen, University Hospital Erlangen, Erlangen, Germany
| | - Martin Regensburger
- Department of Stem Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Department of Molecular Neurology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Center for Rare Diseases Erlangen, University Hospital Erlangen, Erlangen, Germany
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17
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Karpe Y, Chen Z, Li XJ. Stem Cell Models and Gene Targeting for Human Motor Neuron Diseases. Pharmaceuticals (Basel) 2021; 14:565. [PMID: 34204831 PMCID: PMC8231537 DOI: 10.3390/ph14060565] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/05/2021] [Accepted: 06/08/2021] [Indexed: 12/17/2022] Open
Abstract
Motor neurons are large projection neurons classified into upper and lower motor neurons responsible for controlling the movement of muscles. Degeneration of motor neurons results in progressive muscle weakness, which underlies several debilitating neurological disorders including amyotrophic lateral sclerosis (ALS), hereditary spastic paraplegias (HSP), and spinal muscular atrophy (SMA). With the development of induced pluripotent stem cell (iPSC) technology, human iPSCs can be derived from patients and further differentiated into motor neurons. Motor neuron disease models can also be generated by genetically modifying human pluripotent stem cells. The efficiency of gene targeting in human cells had been very low, but is greatly improved with recent gene editing technologies such as zinc-finger nucleases (ZFN), transcription activator-like effector nucleases (TALEN), and CRISPR-Cas9. The combination of human stem cell-based models and gene editing tools provides unique paradigms to dissect pathogenic mechanisms and to explore therapeutics for these devastating diseases. Owing to the critical role of several genes in the etiology of motor neuron diseases, targeted gene therapies have been developed, including antisense oligonucleotides, viral-based gene delivery, and in situ gene editing. This review summarizes recent advancements in these areas and discusses future challenges toward the development of transformative medicines for motor neuron diseases.
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Affiliation(s)
- Yashashree Karpe
- Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, IL 61107, USA; (Y.K.); (Z.C.)
| | - Zhenyu Chen
- Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, IL 61107, USA; (Y.K.); (Z.C.)
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Xue-Jun Li
- Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, IL 61107, USA; (Y.K.); (Z.C.)
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
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18
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Mackay-Sim A. Hereditary Spastic Paraplegia: From Genes, Cells and Networks to Novel Pathways for Drug Discovery. Brain Sci 2021; 11:brainsci11030403. [PMID: 33810178 PMCID: PMC8004882 DOI: 10.3390/brainsci11030403] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/14/2021] [Accepted: 03/18/2021] [Indexed: 12/13/2022] Open
Abstract
Hereditary spastic paraplegia (HSP) is a diverse group of Mendelian genetic disorders affecting the upper motor neurons, specifically degeneration of their distal axons in the corticospinal tract. Currently, there are 80 genes or genomic loci (genomic regions for which the causative gene has not been identified) associated with HSP diagnosis. HSP is therefore genetically very heterogeneous. Finding treatments for the HSPs is a daunting task: a rare disease made rarer by so many causative genes and many potential mutations in those genes in individual patients. Personalized medicine through genetic correction may be possible, but impractical as a generalized treatment strategy. The ideal treatments would be small molecules that are effective for people with different causative mutations. This requires identification of disease-associated cell dysfunctions shared across genotypes despite the large number of HSP genes that suggest a wide diversity of molecular and cellular mechanisms. This review highlights the shared dysfunctional phenotypes in patient-derived cells from patients with different causative mutations and uses bioinformatic analyses of the HSP genes to identify novel cell functions as potential targets for future drug treatments for multiple genotypes.
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Affiliation(s)
- Alan Mackay-Sim
- Griffith Institute for Drug Discovery, Griffith University, Brisbane, QLD 4111, Australia
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19
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Chan WWR, Li W, Chang RCC, Lau KF. ARF6-Rac1 signaling-mediated neurite outgrowth is potentiated by the neuronal adaptor FE65 through orchestrating ARF6 and ELMO1. FASEB J 2020; 34:16397-16413. [PMID: 33047393 DOI: 10.1096/fj.202001703r] [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: 07/08/2020] [Revised: 09/13/2020] [Accepted: 10/02/2020] [Indexed: 12/24/2022]
Abstract
Ras-related C3 botulinum toxin substrate 1 (Rac1) is a member of the Rho family of GTPases that functions as a molecular switch to regulate many important cellular events including actin cytoskeleton remodeling during neurite outgrowth. Engulfment and cell motility 1 (ELMO1)-dedicator of cytokinesis 1 (DOCK180) is a bipartite guanine nucleotide exchange factor (GEF) complex that has been reported to activate Rac1 on the plasma membrane (PM). Emerging evidence suggests that the small GTPase ADP ribosylation factor 6 (ARF6) activates Rac1 via the ELMO1/DOCK180 complex. However, the exact mechanism by which ARF6 triggers ELMO1/DOCK180-mediated Rac1 signaling remains unclear. Here, we report that the neuronal scaffold protein FE65 serves as a functional link between ARF6 and ELMO1, allowing the formation of a multimeric signaling complex. Interfering with formation of this complex by transfecting either FE65-binding-defective mutants or FE65 siRNA attenuates both ARF6-ELMO1-mediated Rac1 activation and neurite elongation. Notably, the PM trafficking of ELMO1 is markedly decreased in cells with suppressed expression of either FE65 or ARF6. Likewise, this process is attenuated in the FE65-binding-defective mutants transfected cells. Moreover, overexpression of FE65 increases the amount of ELMO1 in the recycling endosome, an organelle responsible for returning proteins to the PM, whereas knockout of FE65 shows opposite effect. Together, our data indicates that FE65 potentiates ARF6-Rac1 signaling by orchestrating ARF6 and ELMO1 to promote the PM trafficking of ELMO1 via the endosomal recycling pathway, and thus, promotes Rac1-mediated neurite outgrowth.
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Affiliation(s)
- Wai Wa Ray Chan
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Wen Li
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong SAR, China.,Research Laboratory for Biomedical Optics and Molecular Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Raymond Chuen Chung Chang
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, and State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Kwok-Fai Lau
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong SAR, China
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20
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Fowler PC, Byrne DJ, Blackstone C, O’Sullivan NC. Loss of the Mitochondrial Fission GTPase Drp1 Contributes to Neurodegeneration in a Drosophila Model of Hereditary Spastic Paraplegia. Brain Sci 2020; 10:brainsci10090646. [PMID: 32957716 PMCID: PMC7564485 DOI: 10.3390/brainsci10090646] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 09/10/2020] [Accepted: 09/15/2020] [Indexed: 02/03/2023] Open
Abstract
Mitochondrial morphology, distribution and function are maintained by the opposing forces of mitochondrial fission and fusion, the perturbation of which gives rise to several neurodegenerative disorders. The large guanosine triphosphate (GTP)ase dynamin-related protein 1 (Drp1) is a critical regulator of mitochondrial fission by mediating membrane scission, often at points of mitochondrial constriction at endoplasmic reticulum (ER)-mitochondrial contacts. Hereditary spastic paraplegia (HSP) subtype SPG61 is a rare neurodegenerative disorder caused by mutations in the ER-shaping protein Arl6IP1. We have previously reported defects in both the ER and mitochondrial networks in a Drosophila model of SPG61. In this study, we report that knockdown of Arl6IP1 lowers Drp1 protein levels, resulting in reduced ER–mitochondrial contacts and impaired mitochondrial load at the distal ends of long motor neurons. Increasing mitochondrial fission, by overexpression of wild-type Drp1 but not a dominant negative Drp1, increases ER–mitochondrial contacts, restores mitochondrial load within axons and partially rescues locomotor deficits. Arl6IP1 knockdown Drosophila also demonstrate impaired autophagic flux and an accumulation of ubiquitinated proteins, which occur independent of Drp1-mediated mitochondrial fission defects. Together, these findings provide evidence that impaired mitochondrial fission contributes to neurodegeneration in this in vivo model of HSP.
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Affiliation(s)
- Philippa C. Fowler
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute, University College Dublin, Dublin 4, Ireland; (P.C.F.); (D.J.B.)
| | - Dwayne J. Byrne
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute, University College Dublin, Dublin 4, Ireland; (P.C.F.); (D.J.B.)
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA;
| | - Craig Blackstone
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA;
| | - Niamh C. O’Sullivan
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute, University College Dublin, Dublin 4, Ireland; (P.C.F.); (D.J.B.)
- Correspondence: ; Tel.: +353-1-7166762
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21
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Jiao Z, Wu Y, Qu S. Fenpropathrin induces degeneration of dopaminergic neurons via disruption of the mitochondrial quality control system. Cell Death Discov 2020; 6:78. [PMID: 32884840 PMCID: PMC7447795 DOI: 10.1038/s41420-020-00313-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/17/2020] [Accepted: 08/13/2020] [Indexed: 12/13/2022] Open
Abstract
The synthetic pyrethroid derivative, fenpropathrin, is a widely used insecticide. However, a variety of toxic effects in mammals have been reported. In particular, fenpropathrin induces degeneration of dopaminergic neurons and parkinsonism. However, the mechanism of fenpropathrin-induced parkinsonism has remained unknown. In the present study, we investigated the toxic effects and underlying mechanisms of fenpropathrin on perturbing the dopaminergic system both in vivo and in vitro. We found that fenpropathrin induced cellular death of dopaminergic neurons in vivo. Furthermore, fenpropathrin increased the generation of reactive oxygen species, disrupted both mitochondrial function and dynamic networks, impaired synaptic communication, and promoted mitophagy in vitro. In mice, fenpropathrin was administered into the striatum via stereotaxic (ST) injections. ST-injected mice exhibited poor locomotor function at 24 weeks after the first ST injection and the number of tyrosine hydroxylase (TH)-positive cells and level of TH protein in the substantia nigra pars compacta were significantly decreased, as compared to these parameters in vehicle-treated mice. Taken together, our results demonstrate that exposure to fenpropathrin induces a loss of dopaminergic neurons and partially mimics the pathologic features of Parkinson's disease. These findings suggest that fenpropathrin may induce neuronal degeneration via dysregulation of mitochondrial function and the mitochondrial quality control system.
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Affiliation(s)
- Zhigang Jiao
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 Guangdong China
- Central Laboratory and Department of Neurology, Shunde Hospital, Southern Medical University (The First People’s Hospital of Shunde Foshan), Foshan, 528300 Guangdong China
- Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangzhou, 510515 Guangdong China
- School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515 Guangdong China
| | - Yixuan Wu
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 Guangdong China
- Central Laboratory and Department of Neurology, Shunde Hospital, Southern Medical University (The First People’s Hospital of Shunde Foshan), Foshan, 528300 Guangdong China
- Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangzhou, 510515 Guangdong China
- School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515 Guangdong China
| | - Shaogang Qu
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 Guangdong China
- Central Laboratory and Department of Neurology, Shunde Hospital, Southern Medical University (The First People’s Hospital of Shunde Foshan), Foshan, 528300 Guangdong China
- Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangzhou, 510515 Guangdong China
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22
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Lin X, Su HZ, Dong EL, Lin XH, Zhao M, Yang C, Wang C, Wang J, Chen YJ, Yu H, Xu J, Ma LX, Xiong ZQ, Wang N, Chen WJ. Stop-gain mutations in UBAP1 cause pure autosomal-dominant spastic paraplegia. Brain 2020; 142:2238-2252. [PMID: 31203368 DOI: 10.1093/brain/awz158] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 03/14/2019] [Accepted: 04/15/2019] [Indexed: 12/15/2022] Open
Abstract
Hereditary spastic paraplegias refer to a heterogeneous group of neurodegenerative disorders resulting from degeneration of the corticospinal tract. Clinical characterization of patients with hereditary spastic paraplegias represents progressive spasticity, exaggerated reflexes and muscular weakness. Here, to expand on the increasingly broad pools of previously unknown hereditary spastic paraplegia causative genes and subtypes, we performed whole exome sequencing for six affected and two unaffected individuals from two unrelated Chinese families with an autosomal dominant hereditary spastic paraplegia and lacking mutations in known hereditary spastic paraplegia implicated genes. The exome sequencing revealed two stop-gain mutations, c.247_248insGTGAATTC (p.I83Sfs*11) and c.526G>T (p.E176*), in the ubiquitin-associated protein 1 (UBAP1) gene, which co-segregated with the spastic paraplegia. We also identified two UBAP1 frameshift mutations, c.324_325delCA (p.H108Qfs*10) and c.425_426delAG (p.K143Sfs*15), in two unrelated families from an additional 38 Chinese pedigrees with autosomal dominant hereditary spastic paraplegias and lacking mutations in known causative genes. The primary disease presentation was a pure lower limb predominant spastic paraplegia. In vivo downregulation of Ubap1 in zebrafish causes abnormal organismal morphology, inhibited motor neuron outgrowth, decreased mobility, and shorter lifespan. UBAP1 is incorporated into endosomal sorting complexes required for transport complex I and binds ubiquitin to function in endosome sorting. Patient-derived truncated form(s) of UBAP1 cause aberrant endosome clustering, pronounced endosome enlargement, and cytoplasmic accumulation of ubiquitinated proteins in HeLa cells and wild-type mouse cortical neuron cultures. Biochemical and immunocytochemical experiments in cultured cortical neurons derived from transgenic Ubap1flox mice confirmed that disruption of UBAP1 leads to dysregulation of both early endosome processing and ubiquitinated protein sorting. Strikingly, deletion of Ubap1 promotes neurodegeneration, potentially mediated by apoptosis. Our study provides genetic and biochemical evidence that mutations in UBAP1 can cause pure autosomal dominant spastic paraplegia.
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Affiliation(s)
- Xiang Lin
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
- Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou 350005, China
| | - Hui-Zhen Su
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - En-Lin Dong
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Xiao-Hong Lin
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Miao Zhao
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Can Yang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Chong Wang
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Jie Wang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yi-Jun Chen
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Hongjie Yu
- Program for Personalized Cancer Care, NorthShore University HealthSystem, Evanston, IL 60201, USA
| | - Jianfeng Xu
- Program for Personalized Cancer Care, NorthShore University HealthSystem, Evanston, IL 60201, USA
| | - Li-Xiang Ma
- Department of Anatomy, Histology and Embryology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Zhi-Qi Xiong
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Ning Wang
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
- Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou 350005, China
| | - Wan-Jin Chen
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
- Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou 350005, China
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23
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Bakula D, Scheibye-Knudsen M. MitophAging: Mitophagy in Aging and Disease. Front Cell Dev Biol 2020; 8:239. [PMID: 32373609 PMCID: PMC7179682 DOI: 10.3389/fcell.2020.00239] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 03/23/2020] [Indexed: 12/19/2022] Open
Abstract
Maintaining mitochondrial health is emerging as a keystone in aging and associated diseases. The selective degradation of mitochondria by mitophagy is of particular importance in keeping a pristine mitochondrial pool. Indeed, inherited monogenic diseases with defects in mitophagy display complex multisystem pathologies but particularly progressive neurodegeneration. Fortunately, therapies are being developed that target mitophagy allowing new hope for treatments for previously incurable diseases. Herein, we describe mitophagy and associated diseases, coin the term mitophaging and describe new small molecule interventions that target different steps in the mitophagic pathway. Consequently, several age-associated diseases may be treated by targeting mitophagy.
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Affiliation(s)
- Daniela Bakula
- Department of Cellular and Molecular Medicine, Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
| | - Morten Scheibye-Knudsen
- Department of Cellular and Molecular Medicine, Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
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24
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Krude H, Biebermann H, Schuelke M, Müller TD, Tschöp M. Allan-Herndon-Dudley-Syndrome: Considerations about the Brain Phenotype with Implications for Treatment Strategies. Exp Clin Endocrinol Diabetes 2020; 128:414-422. [PMID: 32242326 DOI: 10.1055/a-1108-1456] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Despite its first description more than 75 years ago, effective treatment for "Allan-Herndon-Dudley-Syndrome (AHDS)", an X-linked thyroid hormone transporter defect, is unavailable. Mutations in the SLC16A2 gene have been discovered to be causative for AHDS in 2004, but a comprehensive understanding of the function of the encoded protein, monocarboxylate transporter 8 (MCT8), is incomplete. Patients with AHDS suffer from neurodevelopmental delay, as well as extrapyramidal (dystonia, chorea, athetosis), pyramidal (spasticity), and cerebellar symptoms (ataxia). This suggests an affection of the pyramidal tracts, basal ganglia, and cerebellum, most likely already during fetal brain development. The function of other brain areas relevant for mood, behavior, and vigilance seems to be intact. An optimal treatment strategy should thus aim to deliver T3 to these relevant structures at the correct time points during development. A potential therapeutic strategy meeting these needs might be the delivery of T3 via a "Trojan horse mechanism" by which T3 is delivered into target cells by a thyroid hormone transporter independent T3 internalization.
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Affiliation(s)
- Heiko Krude
- Institute of Experimental Pediatric Endocrinology, Charité - Universitätsmedizin, Berlin, Germany
| | - Heike Biebermann
- Institute of Experimental Pediatric Endocrinology, Charité - Universitätsmedizin, Berlin, Germany
| | - Markus Schuelke
- Department of Neuropediatrics, Charité - Universitätsmedizin, Berlin, Germany
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Centre Munich, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany.,Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany
| | - Matthias Tschöp
- Division of Metabolic Diseases, Technische Universität München, Munich, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany.,Helmholtz Zentrum München, Germany
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25
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Suzuki N, Akiyama T, Warita H, Aoki M. Omics Approach to Axonal Dysfunction of Motor Neurons in Amyotrophic Lateral Sclerosis (ALS). Front Neurosci 2020; 14:194. [PMID: 32269505 PMCID: PMC7109447 DOI: 10.3389/fnins.2020.00194] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 02/24/2020] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is an intractable adult-onset neurodegenerative disease that leads to the loss of upper and lower motor neurons (MNs). The long axons of MNs become damaged during the early stages of ALS. Genetic and pathological analyses of ALS patients have revealed dysfunction in the MN axon homeostasis. However, the molecular pathomechanism for the degeneration of axons in ALS has not been fully elucidated. This review provides an overview of the proposed axonal pathomechanisms in ALS, including those involving the neuronal cytoskeleton, cargo transport within axons, axonal energy supply, clearance of junk protein, neuromuscular junctions (NMJs), and aberrant axonal branching. To improve understanding of the global changes in axons, the review summarizes omics analyses of the axonal compartments of neurons in vitro and in vivo, including a motor nerve organoid approach that utilizes microfluidic devices developed by this research group. The review also discusses the relevance of intra-axonal transcription factors frequently identified in these omics analyses. Local axonal translation and the relationship among these pathomechanisms should be pursued further. The development of novel strategies to analyze axon fractions provides a new approach to establishing a detailed understanding of resilience of long MN and MN pathology in ALS.
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Affiliation(s)
- Naoki Suzuki
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan.,Department of Neurology, Shodo-kai Southern Tohoku General Hospital, Miyagi, Japan
| | - Tetsuya Akiyama
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
| | - Hitoshi Warita
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
| | - Masashi Aoki
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
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26
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Mou Y, Mukte S, Chai E, Dein J, Li XJ. Analyzing Mitochondrial Transport and Morphology in Human Induced Pluripotent Stem Cell-Derived Neurons in Hereditary Spastic Paraplegia. J Vis Exp 2020. [PMID: 32090993 DOI: 10.3791/60548] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Neurons have intense demands for high energy in order to support their functions. Impaired mitochondrial transport along axons has been observed in human neurons, which may contribute to neurodegeneration in various disease states. Although it is challenging to examine mitochondrial dynamics in live human nerves, such paradigms are critical for studying the role of mitochondria in neurodegeneration. Described here is a protocol for analyzing mitochondrial transport and mitochondrial morphology in forebrain neuron axons derived from human induced pluripotent stem cells (iPSCs). The iPSCs are differentiated into telencephalic glutamatergic neurons using well-established methods. Mitochondria of the neurons are stained with MitoTracker CMXRos, and mitochondrial movement within the axons are captured using a live-cell imaging microscope equipped with an incubator for cell culture. Time-lapse images are analyzed using software with "MultiKymograph", "Bioformat importer", and "Macros" plugins. Kymographs of mitochondrial transport are generated, and average mitochondrial velocity in the anterograde and retrograde directions is read from the kymograph. Regarding mitochondrial morphology analysis, mitochondrial length, area, and aspect ratio are obtained using the ImageJ. In summary, this protocol allows characterization of mitochondrial trafficking along axons and analysis of their morphology to facilitate studies of neurodegenerative diseases.
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Affiliation(s)
- Yongchao Mou
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford; Department of Bioengineering, University of Illinois at Chicago
| | - Sukhada Mukte
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford
| | - Eric Chai
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford
| | - Joshua Dein
- MD Program, University of Illinois College of Medicine Rockford
| | - Xue-Jun Li
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford; Department of Bioengineering, University of Illinois at Chicago;
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27
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Behne R, Teinert J, Wimmer M, D’Amore A, Davies AK, Scarrott JM, Eberhardt K, Brechmann B, Chen IPF, Buttermore ED, Barrett L, Dwyer S, Chen T, Hirst J, Wiesener A, Segal D, Martinuzzi A, Duarte ST, Bennett JT, Bourinaris T, Houlden H, Roubertie A, Santorelli FM, Robinson M, Azzouz M, Lipton JO, Borner GHH, Sahin M, Ebrahimi-Fakhari D. Adaptor protein complex 4 deficiency: a paradigm of childhood-onset hereditary spastic paraplegia caused by defective protein trafficking. Hum Mol Genet 2020; 29:320-334. [PMID: 31915823 PMCID: PMC7001721 DOI: 10.1093/hmg/ddz310] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/22/2019] [Accepted: 12/05/2019] [Indexed: 12/25/2022] Open
Abstract
Deficiency of the adaptor protein complex 4 (AP-4) leads to childhood-onset hereditary spastic paraplegia (AP-4-HSP): SPG47 (AP4B1), SPG50 (AP4M1), SPG51 (AP4E1) and SPG52 (AP4S1). This study aims to evaluate the impact of loss-of-function variants in AP-4 subunits on intracellular protein trafficking using patient-derived cells. We investigated 15 patient-derived fibroblast lines and generated six lines of induced pluripotent stem cell (iPSC)-derived neurons covering a wide range of AP-4 variants. All patient-derived fibroblasts showed reduced levels of the AP4E1 subunit, a surrogate for levels of the AP-4 complex. The autophagy protein ATG9A accumulated in the trans-Golgi network and was depleted from peripheral compartments. Western blot analysis demonstrated a 3-5-fold increase in ATG9A expression in patient lines. ATG9A was redistributed upon re-expression of AP4B1 arguing that mistrafficking of ATG9A is AP-4-dependent. Examining the downstream effects of ATG9A mislocalization, we found that autophagic flux was intact in patient-derived fibroblasts both under nutrient-rich conditions and when autophagy is stimulated. Mitochondrial metabolism and intracellular iron content remained unchanged. In iPSC-derived cortical neurons from patients with AP4B1-associated SPG47, AP-4 subunit levels were reduced while ATG9A accumulated in the trans-Golgi network. Levels of the autophagy marker LC3-II were reduced, suggesting a neuron-specific alteration in autophagosome turnover. Neurite outgrowth and branching were reduced in AP-4-HSP neurons pointing to a role of AP-4-mediated protein trafficking in neuronal development. Collectively, our results establish ATG9A mislocalization as a key marker of AP-4 deficiency in patient-derived cells, including the first human neuron model of AP-4-HSP, which will aid diagnostic and therapeutic studies.
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Affiliation(s)
- Robert Behne
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Neurology, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Julian Teinert
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Miriam Wimmer
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Angelica D’Amore
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Molecular Medicine, IRCCS Fondazione Stella Maris, 56018 Pisa, Italy
| | - Alexandra K Davies
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Joseph M Scarrott
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield S10 2HQ, UK
| | - Kathrin Eberhardt
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Barbara Brechmann
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Ivy Pin-Fang Chen
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Elizabeth D Buttermore
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Lee Barrett
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Sean Dwyer
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Teresa Chen
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jennifer Hirst
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Antje Wiesener
- Institute of Human Genetics, Friedrich-Alexander Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Devorah Segal
- Division of Pediatric Neurology, Department of Pediatrics, Weill Cornell Medicine, New York City, NY 10021, USA
| | - Andrea Martinuzzi
- Scientific Institute, IRCCS E. Medea, Unità Operativa Conegliano, 31015 Treviso, Italy
| | - Sofia T Duarte
- Department of Pediatric Neurology, Centro Hospitalar de Lisboa Central, 1169-050 Lisbon, Portugal
| | - James T Bennett
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA 98195, USA
| | - Thomas Bourinaris
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1E 6BT, UK
| | - Henry Houlden
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1E 6BT, UK
| | | | | | - Margaret Robinson
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Mimoun Azzouz
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield S10 2HQ, UK
| | - Jonathan O Lipton
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Georg H H Borner
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Mustafa Sahin
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Darius Ebrahimi-Fakhari
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
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28
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Fowler PC, Garcia-Pardo ME, Simpson JC, O'Sullivan NC. NeurodegenERation: The Central Role for ER Contacts in Neuronal Function and Axonopathy, Lessons From Hereditary Spastic Paraplegias and Related Diseases. Front Neurosci 2019; 13:1051. [PMID: 31680803 PMCID: PMC6801308 DOI: 10.3389/fnins.2019.01051] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 09/19/2019] [Indexed: 12/17/2022] Open
Abstract
The hereditary spastic paraplegias (HSPs) are a group of inherited neurodegenerative conditions whose characteristic feature is degeneration of the longest axons within the corticospinal tract which leads to progressive spasticity and weakness of the lower limbs. Though highly genetically heterogeneous, the majority of HSP cases are caused by mutations in genes encoding proteins that are responsible for generating and organizing the tubular endoplasmic reticulum (ER). Despite this, the role of the ER within neurons, particularly the long axons affected in HSP, is not well understood. Throughout axons, ER tubules make extensive contacts with other organelles, the cytoskeleton and the plasma membrane. At these ER contacts, protein complexes work in concert to perform specialized functions including organelle shaping, calcium homeostasis and lipid biogenesis, all of which are vital for neuronal survival and may be disrupted by HSP-causing mutations. In this article we summarize the proteins which mediate ER contacts, review the functions these contacts are known to carry out within neurons, and discuss the potential contribution of disruption of ER contacts to axonopathy in HSP.
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Affiliation(s)
- Philippa C Fowler
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - M Elena Garcia-Pardo
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Jeremy C Simpson
- UCD School of Biology and Environmental Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Niamh C O'Sullivan
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
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29
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Jeong B, Kim TH, Kim DS, Shin WH, Lee JR, Kim NS, Lee DY. Spastin Contributes to Neural Development through the Regulation of Microtubule Dynamics in the Primary Cilia of Neural Stem Cells. Neuroscience 2019; 411:76-85. [PMID: 31150727 DOI: 10.1016/j.neuroscience.2019.05.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 04/25/2019] [Accepted: 05/12/2019] [Indexed: 11/15/2022]
Abstract
Spastin is a microtubule-severing enzyme encoded by SPAST, which is broadly expressed in various cell types originated from multiple organs. Even though SPAST is well known as a regulator of the axon growth and arborization in neurons and a genetic factor of hereditary spastic paraplegia, it also takes part in a wide range of other cellular functions including the regulation of cell division and proliferation. In this study, we investigated a novel biological role of spastin in developing brain using Spast deficient mouse embryonic neural stem cells (NSCs) and perinatal mouse brain. We found that the expression of spastin begins at early embryonic stages in mouse brain. Using Spast shRNA treated NSCs and mouse brain, we showed that Spast deficiency leads to decrease of NSC proliferation and neuronal lineage differentiation. Finally, we found that spastin controls NSC proliferation by regulating microtubule dynamics in primary cilia. Collectively, these data demonstrate that spastin controls brain development by the regulation of NSC functions at early developmental stages.
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Affiliation(s)
- Bohyeon Jeong
- Rare Disease Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea; Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon, South Korea
| | - Tae Hwan Kim
- Rare Disease Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Dae-Soo Kim
- Environmental Disease Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea; Department of Bioinformatics, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon, South Korea
| | - Won-Ho Shin
- Department of Predictive Toxicology, Korea Institute of Toxicology, Daejeon 34114, South Korea
| | - Jae-Ran Lee
- Rare Disease Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea; Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon, South Korea
| | - Nam-Soon Kim
- Rare Disease Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea; Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon, South Korea
| | - Da Yong Lee
- Rare Disease Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea; Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon, South Korea.
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30
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Mitochondrial dynamics and their potential as a therapeutic target. Mitochondrion 2019; 49:269-283. [PMID: 31228566 DOI: 10.1016/j.mito.2019.06.002] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 05/02/2019] [Accepted: 06/06/2019] [Indexed: 12/16/2022]
Abstract
Mitochondrial dynamics shape the mitochondrial network and contribute to mitochondrial function and quality control. Mitochondrial fusion and division are integrated into diverse cellular functions and respond to changes in cell physiology. Imbalanced mitochondrial dynamics are associated with a range of diseases that are broadly characterized by impaired mitochondrial function and increased cell death. In various disease models, modulating mitochondrial fusion and division with either small molecules or genetic approaches has improved function. Although additional mechanistic understanding of mitochondrial fusion and division will be critical to inform further therapeutic approaches, mitochondrial dynamics represent a powerful therapeutic target in a wide range of human diseases.
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Baker N, Patel J, Khacho M. Linking mitochondrial dynamics, cristae remodeling and supercomplex formation: How mitochondrial structure can regulate bioenergetics. Mitochondrion 2019; 49:259-268. [PMID: 31207408 DOI: 10.1016/j.mito.2019.06.003] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 05/18/2019] [Accepted: 06/06/2019] [Indexed: 01/21/2023]
Abstract
The dynamic and fluid nature of mitochondria allows for modifications in mitochondrial shape, connectivity and cristae architecture. The precise balance of mitochondrial dynamics is among the most critical features in the control of mitochondrial function. In the past few years, mitochondrial shape has emerged as a key regulatory factor in the determination of the bioenergetic capacity of cells. This is mostly due to the recent discoveries linking changes in cristae organization with supercomplex assembly of the electron transport chain (ETC), also defined as the formation of respirosomes. Here we will review the most current advances demonstrating the impact of mitochondrial dynamics and cristae shape on oxidative metabolism, respiratory efficiency, and redox state. Furthermore, we will discuss the implications of mitochondrial dynamics and supercomplex assembly under physiological and pathological conditions.
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Affiliation(s)
- Nicole Baker
- Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems Biology (OISB), Center for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario, Canada
| | - Jeel Patel
- Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems Biology (OISB), Center for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario, Canada
| | - Mireille Khacho
- Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems Biology (OISB), Center for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario, Canada.
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Elsayed LEO, Eltazi IZM, Ahmed AEM, Stevanin G. Hereditary spastic paraplegias: time for an objective case definition and a new nosology for neurogenetic disorders to facilitate biomarker/therapeutic studies. Expert Rev Neurother 2019; 19:409-415. [PMID: 31037979 DOI: 10.1080/14737175.2019.1608824] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Hereditary spastic paraplegias (HSPs) are heterogeneous neurodegenerative disorders characterized by progressive lower limb weakness and spasticity as core symptoms of the degeneration of the corticospinal motor neurons. Even after exclusion of infectious and toxic mimickers of these disorders, the definitive diagnosis remains tricky, mainly in sporadic forms, as there is significant overlap with other disorders. Since their first description, various attempts failed to reach an appropriate classification. This was due to the constant expansion of the clinical spectrum of these diseases and the discovery of new genes, a significant number of them was involved in overlapping diseases. Areas covered: In this perspective review, an extensive literature study was conducted on the historical progress of HSP research. We also revised the previous and the current classifications of HSP and the closely related neurogenetic disorders and analyzed the areas of overlap. Expert opinion: There is undeniable need for objective case definition and reclassification of all neurogenetic disorders including HSPs, a prerequisite to improve patient follow-up, biomarker identification and develop therapeutics. The challenge is to understand why mutations can give rise to multiple phenotypic presentations along this spectrum of diseases in which the corticospinal tract is affected.
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Affiliation(s)
| | - Isra Z M Eltazi
- a Faculty of Medicine , University of Khartoum , Khartoum , Sudan
| | - Ammar E M Ahmed
- a Faculty of Medicine , University of Khartoum , Khartoum , Sudan
| | - Giovanni Stevanin
- b Basic to Translational Neurogenetics team , Institut du Cerveau et de la Moelle épinière, INSERM U1127, CNRS UMR7225, Sorbonne Université UMR_S1127 , Paris , France.,c Neurogenetics team , Ecole Pratique des Hautes Etudes, EPHE, PSL Research University , Paris , France
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Khundadze M, Ribaudo F, Hussain A, Rosentreter J, Nietzsche S, Thelen M, Winter D, Hoffmann B, Afzal MA, Hermann T, de Heus C, Piskor EM, Kosan C, Franzka P, von Kleist L, Stauber T, Klumperman J, Damme M, Proikas-Cezanne T, Hübner CA. A mouse model for SPG48 reveals a block of autophagic flux upon disruption of adaptor protein complex five. Neurobiol Dis 2019; 127:419-431. [PMID: 30930081 DOI: 10.1016/j.nbd.2019.03.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 02/25/2019] [Accepted: 03/24/2019] [Indexed: 12/25/2022] Open
Abstract
Hereditary spastic paraplegia is a spastic gait disorder that arises from degeneration of corticospinal axons. The subtype SPG48 is associated with mutations in the zeta subunit of the adaptor protein complex five (AP5). AP5 function and the pathophysiology of SPG48 are only poorly understood. Here, we report an AP5 zeta knockout mouse, which shows an age-dependent degeneration of corticospinal axons. Our analysis of knockout fibroblasts supports a trafficking defect from late endosomes to the transGolgi network and reveals a structural defect of the Golgi. We further show that both autophagic flux and the recycling of lysosomes from autolysosomes were impaired in knockout cells. In vivo, we observe an increase of autophagosomes and autolysosomes and, at later stages, the accumulation of intracellular waste in neurons. Taken together, we propose that loss of AP5 function blocks autophagy and thus leads to the aberrant accumulation of autophagic cargo, which finally results in axon degeneration.
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Affiliation(s)
- Mukhran Khundadze
- Institute of Human Genetics, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07747, Germany.
| | - Federico Ribaudo
- Institute of Human Genetics, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07747, Germany
| | - Adeela Hussain
- Institute of Human Genetics, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07747, Germany
| | - Jan Rosentreter
- Institute of Human Genetics, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07747, Germany
| | - Sandor Nietzsche
- Electron Microscopy Center, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07743, Germany
| | - Melanie Thelen
- Institute for Biochemistry and Molecular Biology, University of Bonn, Bonn 53115, Germany
| | - Dominic Winter
- Institute for Biochemistry and Molecular Biology, University of Bonn, Bonn 53115, Germany
| | - Birgit Hoffmann
- Biomolecular Photonics Group, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07743, Germany
| | - Muhammad Awais Afzal
- Institute of Human Genetics, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07747, Germany
| | - Tanja Hermann
- Institute of Human Genetics, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07747, Germany
| | - Cecilia de Heus
- Department of Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht 3584, Netherlands
| | - Eva-Maria Piskor
- Institute of Biochemistry and Biophysics, Friedrich-Schiller-University Jena, Jena 07743, Germany
| | - Christian Kosan
- Institute of Biochemistry and Biophysics, Friedrich-Schiller-University Jena, Jena 07743, Germany
| | - Patricia Franzka
- Institute of Human Genetics, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07747, Germany
| | - Lisa von Kleist
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin 14195, Germany
| | - Tobias Stauber
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin 14195, Germany
| | - Judith Klumperman
- Department of Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht 3584, Netherlands
| | - Markus Damme
- Institute of Biochemistry, Christian-Albrechts-University Kiel, Kiel 24118, Germany
| | - Tassula Proikas-Cezanne
- Department of Molecular Biology, Eberhard Karls University Tübingen, Tübingen 72076, Germany
| | - Christian A Hübner
- Institute of Human Genetics, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07747, Germany.
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Mou Y, Li XJ. Rescue axonal defects by targeting mitochondrial dynamics in hereditary spastic paraplegias. Neural Regen Res 2019; 14:574-577. [PMID: 30632492 PMCID: PMC6352593 DOI: 10.4103/1673-5374.248108] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Impaired axonal development and degeneration underlie debilitating neurodegenerative diseases including hereditary spastic paraplegia, a large group of inherited diseases. Hereditary spastic paraplegia is caused by retrograde degeneration of the long corticospinal tract axons, leading to progressive spasticity and weakness of leg and hip muscles. There are over 70 subtypes with various underlying pathophysiological processes, such as defective vesicular trafficking, lipid metabolism, organelle shaping, axonal transport, and mitochondrial dysfunction. Although hereditary spastic paraplegia consists of various subtypes with different pathological characteristics, defects in mitochondrial morphology and function emerge as one of the common cellular themes in hereditary spastic paraplegia. Mitochondrial morphology and function are remodeled by mitochondrial dynamics regulated by several key fission and fusion mediators. However, the role of mitochondrial dynamics in axonal defects of hereditary spastic paraplegia remains largely unknown. Recently, studies reported perturbed mitochondrial morphology in hereditary spastic paraplegia neurons. Moreover, downregulation of mitochondrial fission regulator dynamin-related protein 1, both pharmacologically and genetically, could rescue axonal outgrowth defects in hereditary spastic paraplegia neurons, providing a potential therapeutic target for treating these hereditary spastic paraplegia. This mini-review will describe the regulation of mitochondrial fission/fusion, the link between mitochondrial dynamics and axonal defects, and the recent progress on the role of mitochondrial dynamics in axonal defects of hereditary spastic paraplegia.
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Affiliation(s)
- Yongchao Mou
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford; Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Xue-Jun Li
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford; Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
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Trummer B, Haubenberger D, Blackstone C. Clinical Trial Designs and Measures in Hereditary Spastic Paraplegias. Front Neurol 2018; 9:1017. [PMID: 30627115 PMCID: PMC6309810 DOI: 10.3389/fneur.2018.01017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 11/12/2018] [Indexed: 01/19/2023] Open
Abstract
Hereditary spastic paraplegias (HSPs) are a large group of genetically-diverse neurologic disorders characterized clinically by a common feature of lower extremity spasticity and gait difficulties. Current therapies are predominantly symptomatic, and even then usually provide inadequate relief of symptoms. Going forward, HSP therapeutics development requires a systematic analysis of quantifiable measures and tools to assess treatment response. This review summarizes promising therapeutic targets, assessment measures, and previous clinical trials for the HSPs. Oxidative stress, signaling pathways, microtubule dynamics, and gene rescue/replacement have been proposed as potential treatment targets or modalities. Quantitative evaluation of pre-clinical rodent HSP models emphasize rotarod performance, foot base angle, grip strength, stride length, beam walking, critical speed, and body weight. Clinical measures of HSP in humans include 10-m gait velocity, the Spastic Paraplegia Rating Scale (SPRS), Ashworth Spasticity Scale, Fugl-Meyer Scale, timed up-and-go, and the Gillette Functional Assessment Questionnaire. We conducted a broad search for past clinical trials in HSPs and identified trials that investigated pharmacological agents including atorvastatin, gabapentin, L-threonine, botulinum toxin, dalfampridine, methylphenidate, and baclofen. We provide recommendations for future HSP treatment directions based on these prior research experiences as well as regulatory insight.
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Affiliation(s)
- Brian Trummer
- Neurogenetics Branch, Clinical Research Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
- Clinical Trials Unit, Clinical Research Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Dietrich Haubenberger
- Clinical Trials Unit, Clinical Research Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Craig Blackstone
- Neurogenetics Branch, Clinical Research Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
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Marroqui L, Tudurí E, Alonso-Magdalena P, Quesada I, Nadal Á, Dos Santos RS. Mitochondria as target of endocrine-disrupting chemicals: implications for type 2 diabetes. J Endocrinol 2018; 239:R27-R45. [PMID: 30072426 DOI: 10.1530/joe-18-0362] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 08/01/2018] [Indexed: 12/12/2022]
Abstract
Type 2 diabetes is a chronic, heterogeneous syndrome characterized by insulin resistance and pancreatic β-cell dysfunction or death. Among several environmental factors contributing to type 2 diabetes development, endocrine-disrupting chemicals (EDCs) have been receiving special attention. These chemicals include a wide variety of pollutants, from components of plastic to pesticides, with the ability to modulate endocrine system function. EDCs can affect multiple cellular processes, including some related to energy production and utilization, leading to alterations in energy homeostasis. Mitochondria are primarily implicated in cellular energy conversion, although they also participate in other processes, such as hormone secretion and apoptosis. In fact, mitochondrial dysfunction due to reduced oxidative capacity, impaired lipid oxidation and increased oxidative stress has been linked to insulin resistance and type 2 diabetes. Herein, we review the main mechanisms whereby metabolism-disrupting chemical (MDC), a subclass of EDCs that disturbs energy homeostasis, cause mitochondrial dysfunction, thus contributing to the establishment of insulin resistance and type 2 diabetes. We conclude that MDC-induced mitochondrial dysfunction, which is mainly characterized by perturbations in mitochondrial bioenergetics, biogenesis and dynamics, excessive reactive oxygen species production and activation of the mitochondrial pathway of apoptosis, seems to be a relevant mechanism linking MDCs to type 2 diabetes development.
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Affiliation(s)
- Laura Marroqui
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM) and Institute of Bioengineering, Miguel Hernández University of Elche, Alicante, Spain
| | - Eva Tudurí
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM) and Institute of Bioengineering, Miguel Hernández University of Elche, Alicante, Spain
| | - Paloma Alonso-Magdalena
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM) and Institute of Bioengineering, Miguel Hernández University of Elche, Alicante, Spain
| | - Iván Quesada
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM) and Institute of Bioengineering, Miguel Hernández University of Elche, Alicante, Spain
| | - Ángel Nadal
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM) and Institute of Bioengineering, Miguel Hernández University of Elche, Alicante, Spain
| | - Reinaldo Sousa Dos Santos
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM) and Institute of Bioengineering, Miguel Hernández University of Elche, Alicante, Spain
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Virga DM, Capps J, Vohra BPS. Enteric Neurodegeneration is Mediated Through Independent Neuritic and Somal Mechanisms in Rotenone and MPP+ Toxicity. Neurochem Res 2018; 43:2288-2303. [PMID: 30259276 DOI: 10.1007/s11064-018-2649-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 09/18/2018] [Accepted: 09/24/2018] [Indexed: 01/09/2023]
Abstract
Gut motility malfunction and pathological changes in the enteric nervous system (ENS) are observed in the early stages of Parkinson's disease (PD). In many cases disturbances in the autonomous functions such as gut motility precedes the observed loss of central motor functions in PD. However, the mechanism by which ENS degeneration occurs in PD is unknown. We show that parkinsonian mimetics rotenone and MPP+ induce neurite degeneration that precedes cell death in primary enteric neurons cultured in vitro. If the neuronal death signals originate from degenerating neurites, neuronal death should be prevented by inhibiting neurite degeneration. Our data demonstrate that overexpression of cytNmnat1, an axon protector, maintains healthy neurites in enteric neurons treated with either of the parkinsonian mimetics, but cannot protect the soma. We also demonstrate that neurite protection via cytNmnat1 is independent of mitochondrial dynamics or ATP levels. Overexpression of Bcl-xl, an anti-apoptotic factor, protects both the neuronal cell body and the neurites in both rotenone and MPP+ treated enteric neurons. Our data reveals that Bcl-xl and cytNmnat1 act through separate mechanisms to protect enteric neurites. Our findings suggest that neurite protection alone is not sufficient to inhibit enteric neuronal degeneration in rotenone or MPP+ toxicity, and enteric neurodegeneration in PD may be occurring through independent somatic and neuritic mechanisms. Thus, therapies targeting both axonal and somal protection can be important in finding interventions for enteric symptoms in PD.
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Affiliation(s)
- Daniel M Virga
- Biology Department, William Jewell College, Liberty, MO, 64068, USA
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Jessica Capps
- Biology Department, William Jewell College, Liberty, MO, 64068, USA
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