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Franchino CA, Brughera M, Baderna V, De Ritis D, Rocco A, Seneca S, Regal L, Podini P, D’Antonio M, Toro C, Quattrini A, Scalais E, Maltecca F. Sustained OMA1-mediated integrated stress response is beneficial for spastic ataxia type 5. Brain 2024; 147:1043-1056. [PMID: 37804316 PMCID: PMC10907083 DOI: 10.1093/brain/awad340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 08/28/2023] [Accepted: 09/12/2023] [Indexed: 10/09/2023] Open
Abstract
AFG3L2 is a mitochondrial protease exerting protein quality control in the inner mitochondrial membrane. Heterozygous AFG3L2 mutations cause spinocerebellar ataxia type 28 (SCA28) or dominant optic atrophy type 12 (DOA12), while biallelic AFG3L2 mutations result in the rare and severe spastic ataxia type 5 (SPAX5). The clinical spectrum of SPAX5 includes childhood-onset cerebellar ataxia, spasticity, dystonia and myoclonic epilepsy. We previously reported that the absence or mutation of AFG3L2 leads to the accumulation of mitochondria-encoded proteins, causing the overactivation of the stress-sensitive protease OMA1, which over-processes OPA1, leading to mitochondrial fragmentation. Recently, OMA1 has been identified as the pivotal player communicating mitochondrial stress to the cytosol via a pathway involving the inner mitochondrial membrane protein DELE1 and the cytosolic kinase HRI, thus eliciting the integrated stress response. In general, the integrated stress response reduces global protein synthesis and drives the expression of cytoprotective genes that allow cells to endure proteotoxic stress. However, the relevance of the OMA1-DELE1-HRI axis in vivo, and especially in a human CNS disease context, has been poorly documented thus far. In this work, we demonstrated that mitochondrial proteotoxicity in the absence/mutation of AFG3L2 activates the OMA1-DELE1-HRI pathway eliciting the integrated stress response. We found enhanced OMA1-dependent processing of DELE1 upon depletion of AFG3L2. Also, in both skin fibroblasts from SPAX5 patients (including a novel case) and in the cerebellum of Afg3l2-/- mice we detected increased phosphorylation of the α-subunit of the eukaryotic translation initiation factor 2 (eIF2α), increased levels of ATF4 and strong upregulation of its downstream targets (Chop, Chac1, Ppp1r15a and Ffg21). Silencing of DELE1 or HRI in SPAX5 fibroblasts (where OMA1 is overactivated at basal state) reduces eIF2α phosphorylation and affects cell growth. In agreement, pharmacological potentiation of integrated stress response via Sephin-1, a drug that selectively inhibits the stress-induced eIF2alpha phosphatase GADD34 (encoded by Ppp1r15a), improved cell growth of SPAX5 fibroblasts and cell survival and dendritic arborization ex vivo in primary Afg3l2-/- Purkinje neurons. Notably, Sephin-1 treatment in vivo extended the lifespan of Afg3l2-/- mice, improved Purkinje neuron morphology, mitochondrial ultrastructure and respiratory capacity. These data indicate that activation of the OMA1-DELE1-HRI pathway is protective in the context of SPAX5. Pharmacological tuning of the integrated stress response may represent a future therapeutic strategy for SPAX5 and other cerebellar ataxias caused by impaired mitochondrial proteostasis.
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Affiliation(s)
- Camilla Aurora Franchino
- Mitochondrial Dysfunctions in Neurodegeneration Unit, Division of Neuroscience, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Martina Brughera
- Mitochondrial Dysfunctions in Neurodegeneration Unit, Division of Neuroscience, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Valentina Baderna
- Mitochondrial Dysfunctions in Neurodegeneration Unit, Division of Neuroscience, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Daniele De Ritis
- Mitochondrial Dysfunctions in Neurodegeneration Unit, Division of Neuroscience, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Alessandra Rocco
- Mitochondrial Dysfunctions in Neurodegeneration Unit, Division of Neuroscience, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Sara Seneca
- Medical Center of Genetic, UZ-VUB, Vrije Universiteit Brussels, 1090 Brussels Jette, Belgium
| | - Luc Regal
- Pediatric Neurology and Metabolism, UZ-VUB, Vrije Universiteit Brussels, 1090 Brussels Jette, Belgium
| | - Paola Podini
- Experimental Neuropathology Unit, Division of Neuroscience and Institute of Experimental Neurology, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Maurizio D’Antonio
- Biology of Myelin Unit, Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Camilo Toro
- NIH Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Angelo Quattrini
- Experimental Neuropathology Unit, Division of Neuroscience and Institute of Experimental Neurology, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Emmanuel Scalais
- Department of Pediatric, Division of Pediatric Neurology, Centre Hospitalier de Luxembourg, L1210 Luxembourg, Luxembourg
| | - Francesca Maltecca
- Mitochondrial Dysfunctions in Neurodegeneration Unit, Division of Neuroscience, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
- Università Vita-Salute San Raffaele, 20132 Milan, Italy
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2
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Leung TCS, Fields E, Rana N, Shen RYL, Bernstein AE, Cook AA, Phillips DE, Watt AJ. Mitochondrial damage and impaired mitophagy contribute to disease progression in SCA6. Acta Neuropathol 2024; 147:26. [PMID: 38286873 PMCID: PMC10824820 DOI: 10.1007/s00401-023-02680-z] [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: 10/30/2023] [Revised: 12/18/2023] [Accepted: 12/27/2023] [Indexed: 01/31/2024]
Abstract
Spinocerebellar ataxia type 6 (SCA6) is a neurodegenerative disease that manifests in midlife and progressively worsens with age. SCA6 is rare, and many patients are not diagnosed until long after disease onset. Whether disease-causing cellular alterations differ at different disease stages is currently unknown, but it is important to answer this question in order to identify appropriate therapeutic targets across disease duration. We used transcriptomics to identify changes in gene expression at disease onset in a well-established mouse model of SCA6 that recapitulates key disease features. We observed both up- and down-regulated genes with the major down-regulated gene ontology terms suggesting mitochondrial dysfunction. We explored mitochondrial function and structure and observed that changes in mitochondrial structure preceded changes in function, and that mitochondrial function was not significantly altered at disease onset but was impaired later during disease progression. We also detected elevated oxidative stress in cells at the same disease stage. In addition, we observed impairment in mitophagy that exacerbates mitochondrial dysfunction at late disease stages. In post-mortem SCA6 patient cerebellar tissue, we observed metabolic changes that are consistent with mitochondrial impairments, supporting our results from animal models being translatable to human disease. Our study reveals that mitochondrial dysfunction and impaired mitochondrial degradation likely contribute to disease progression in SCA6 and suggests that these could be promising targets for therapeutic interventions in particular for patients diagnosed after disease onset.
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Affiliation(s)
| | - Eviatar Fields
- Department of Biology, McGill University, Montreal, QC, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Namrata Rana
- Department of Biology, McGill University, Montreal, QC, Canada
| | | | | | - Anna A Cook
- Department of Biology, McGill University, Montreal, QC, Canada
| | | | - Alanna J Watt
- Department of Biology, McGill University, Montreal, QC, Canada.
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3
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Ghosh Dastidar R, Banerjee S, Lal PB, Ghosh Dastidar S. Multifaceted Roles of AFG3L2, a Mitochondrial ATPase in Relation to Neurological Disorders. Mol Neurobiol 2023:10.1007/s12035-023-03768-z. [PMID: 38012514 DOI: 10.1007/s12035-023-03768-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 11/01/2023] [Indexed: 11/29/2023]
Abstract
AFG3L2 is a zinc metalloprotease and an ATPase localized in an inner mitochondrial membrane involved in mitochondrial quality control of several nuclear- and mitochondrial-encoded proteins. Mutations in AFG3L2 lead to diseases like slow progressive ataxia, which is a neurological disorder. This review delineates the cellular functions of AFG3L2 and its dysfunction that leads to major clinical outcomes, which include spinocerebellar ataxia type 28, spastic ataxia type 5, and optic atrophy type 12. It summarizes all relevant AFG3L2 mutations associated with the clinical outcomes to understand the detailed mechanisms attributable to its structure-related multifaceted roles in proteostasis and quality control. We face early diagnostic challenges of ataxia and optic neuropathy due to asymptomatic parents and variable clinical manifestations due to heterozygosity/homozygosity of AFG3L2 mutations. This review intends to promote AFG3L2 as a putative prognostic or diagnostic marker. Functions, mutations, and clinical manifestations in AFG3L2, a mitochondrial AAA + ATPases.
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Affiliation(s)
- Ranita Ghosh Dastidar
- Department of Biochemistry, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, Madhava Nagar, Manipal, 576104, Karnataka, India.
| | - Saradindu Banerjee
- Centre for Molecular Neurosciences, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, Madhava Nagar, Manipal, 576104, Karnataka, India
| | - Piyush Behari Lal
- Department of Microbiology, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, Madhava Nagar, Manipal, 576104, Karnataka, India.
| | - Somasish Ghosh Dastidar
- Centre for Molecular Neurosciences, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, Madhava Nagar, Manipal, 576104, Karnataka, India.
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4
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Manolaras I, Del Bondio A, Griso O, Reutenauer L, Eisenmann A, Habermann BH, Puccio H. Mitochondrial dysfunction and calcium dysregulation in COQ8A-ataxia Purkinje neurons are rescued by CoQ10 treatment. Brain 2023; 146:3836-3850. [PMID: 36960552 DOI: 10.1093/brain/awad099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 01/11/2023] [Accepted: 03/06/2023] [Indexed: 03/25/2023] Open
Abstract
COQ8A-ataxia is a rare form of neurodegenerative disorder due to mutations in the COQ8A gene. The encoded mitochondrial protein is involved in the regulation of coenzyme Q10 biosynthesis. Previous studies on the constitutive Coq8a-/- mice indicated specific alterations of cerebellar Purkinje neurons involving altered electrophysiological function and dark cell degeneration. In the present manuscript, we extend our understanding of the contribution of Purkinje neuron dysfunction to the pathology. By generating a Purkinje-specific conditional COQ8A knockout, we demonstrate that loss of COQ8A in Purkinje neurons is the main cause of cerebellar ataxia. Furthermore, through in vivo and in vitro approaches, we show that COQ8A-depleted Purkinje neurons have abnormal dendritic arborizations, altered mitochondria function and intracellular calcium dysregulation. Furthermore, we demonstrate that oxidative phosphorylation, in particular Complex IV, is primarily altered at presymptomatic stages of the disease. Finally, the morphology of primary Purkinje neurons as well as the mitochondrial dysfunction and calcium dysregulation could be rescued by CoQ10 treatment, suggesting that CoQ10 could be a beneficial treatment for COQ8A-ataxia.
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Affiliation(s)
- Ioannis Manolaras
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Department of translational medecine and neurogenetics, 67404 Illkirch, France
- Inserm, U1258, 67404 Illkirch, France
- CNRS, UMR7104, 67404 Illkirch, France
- Université de Strasbourg, 67000 Strasbourg, France
| | - Andrea Del Bondio
- Institut Neuromyogène, Pathophysiology and genetics of the neuron and muscle, Inserm U1315, 69008 Lyon, France
- CNRS, Université Claude Bernard Lyon I, UMR 5261, 69008 Lyon, France
| | - Olivier Griso
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Department of translational medecine and neurogenetics, 67404 Illkirch, France
- Inserm, U1258, 67404 Illkirch, France
- CNRS, UMR7104, 67404 Illkirch, France
- Université de Strasbourg, 67000 Strasbourg, France
| | - Laurence Reutenauer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Department of translational medecine and neurogenetics, 67404 Illkirch, France
- Inserm, U1258, 67404 Illkirch, France
- CNRS, UMR7104, 67404 Illkirch, France
- Université de Strasbourg, 67000 Strasbourg, France
- Institut Neuromyogène, Pathophysiology and genetics of the neuron and muscle, Inserm U1315, 69008 Lyon, France
- CNRS, Université Claude Bernard Lyon I, UMR 5261, 69008 Lyon, France
| | - Aurélie Eisenmann
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Department of translational medecine and neurogenetics, 67404 Illkirch, France
- Inserm, U1258, 67404 Illkirch, France
- CNRS, UMR7104, 67404 Illkirch, France
- Université de Strasbourg, 67000 Strasbourg, France
| | - Bianca H Habermann
- CNRS, Institut de Biologie du Développement de Marseille (IBDM), UMR7288, Aix-Marseille University, 13009 Marseille, France
| | - Hélène Puccio
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Department of translational medecine and neurogenetics, 67404 Illkirch, France
- Inserm, U1258, 67404 Illkirch, France
- CNRS, UMR7104, 67404 Illkirch, France
- Université de Strasbourg, 67000 Strasbourg, France
- Institut Neuromyogène, Pathophysiology and genetics of the neuron and muscle, Inserm U1315, 69008 Lyon, France
- CNRS, Université Claude Bernard Lyon I, UMR 5261, 69008 Lyon, France
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5
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Novorolsky RJ, Kasheke GDS, Hakim A, Foldvari M, Dorighello GG, Sekler I, Vuligonda V, Sanders ME, Renden RB, Wilson JJ, Robertson GS. Preserving and enhancing mitochondrial function after stroke to protect and repair the neurovascular unit: novel opportunities for nanoparticle-based drug delivery. Front Cell Neurosci 2023; 17:1226630. [PMID: 37484823 PMCID: PMC10360135 DOI: 10.3389/fncel.2023.1226630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 06/22/2023] [Indexed: 07/25/2023] Open
Abstract
The neurovascular unit (NVU) is composed of vascular cells, glia, and neurons that form the basic component of the blood brain barrier. This intricate structure rapidly adjusts cerebral blood flow to match the metabolic needs of brain activity. However, the NVU is exquisitely sensitive to damage and displays limited repair after a stroke. To effectively treat stroke, it is therefore considered crucial to both protect and repair the NVU. Mitochondrial calcium (Ca2+) uptake supports NVU function by buffering Ca2+ and stimulating energy production. However, excessive mitochondrial Ca2+ uptake causes toxic mitochondrial Ca2+ overloading that triggers numerous cell death pathways which destroy the NVU. Mitochondrial damage is one of the earliest pathological events in stroke. Drugs that preserve mitochondrial integrity and function should therefore confer profound NVU protection by blocking the initiation of numerous injury events. We have shown that mitochondrial Ca2+ uptake and efflux in the brain are mediated by the mitochondrial Ca2+ uniporter complex (MCUcx) and sodium/Ca2+/lithium exchanger (NCLX), respectively. Moreover, our recent pharmacological studies have demonstrated that MCUcx inhibition and NCLX activation suppress ischemic and excitotoxic neuronal cell death by blocking mitochondrial Ca2+ overloading. These findings suggest that combining MCUcx inhibition with NCLX activation should markedly protect the NVU. In terms of promoting NVU repair, nuclear hormone receptor activation is a promising approach. Retinoid X receptor (RXR) and thyroid hormone receptor (TR) agonists activate complementary transcriptional programs that stimulate mitochondrial biogenesis, suppress inflammation, and enhance the production of new vascular cells, glia, and neurons. RXR and TR agonism should thus further improve the clinical benefits of MCUcx inhibition and NCLX activation by increasing NVU repair. However, drugs that either inhibit the MCUcx, or stimulate the NCLX, or activate the RXR or TR, suffer from adverse effects caused by undesired actions on healthy tissues. To overcome this problem, we describe the use of nanoparticle drug formulations that preferentially target metabolically compromised and damaged NVUs after an ischemic or hemorrhagic stroke. These nanoparticle-based approaches have the potential to improve clinical safety and efficacy by maximizing drug delivery to diseased NVUs and minimizing drug exposure in healthy brain and peripheral tissues.
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Affiliation(s)
- Robyn J. Novorolsky
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Gracious D. S. Kasheke
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Antoine Hakim
- School of Pharmacy, Faculty of Science, University of Waterloo, Waterloo, ON, Canada
| | - Marianna Foldvari
- School of Pharmacy, Faculty of Science, University of Waterloo, Waterloo, ON, Canada
| | - Gabriel G. Dorighello
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Israel Sekler
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben Gurion University, Beersheva, Israel
| | | | | | - Robert B. Renden
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV, United States
| | - Justin J. Wilson
- Department of Chemistry and Chemical Biology, College of Arts and Sciences, Cornell University, Ithaca, NY, United States
| | - George S. Robertson
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Department of Psychiatry, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
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6
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Huang H, Shakkottai VG. Targeting Ion Channels and Purkinje Neuron Intrinsic Membrane Excitability as a Therapeutic Strategy for Cerebellar Ataxia. Life (Basel) 2023; 13:1350. [PMID: 37374132 DOI: 10.3390/life13061350] [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: 03/30/2023] [Revised: 06/03/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
In degenerative neurological disorders such as Parkinson's disease, a convergence of widely varying insults results in a loss of dopaminergic neurons and, thus, the motor symptoms of the disease. Dopamine replacement therapy with agents such as levodopa is a mainstay of therapy. Cerebellar ataxias, a heterogeneous group of currently untreatable conditions, have not been identified to have a shared physiology that is a target of therapy. In this review, we propose that perturbations in cerebellar Purkinje neuron intrinsic membrane excitability, a result of ion channel dysregulation, is a common pathophysiologic mechanism that drives motor impairment and vulnerability to degeneration in cerebellar ataxias of widely differing genetic etiologies. We further propose that treatments aimed at restoring Purkinje neuron intrinsic membrane excitability have the potential to be a shared therapy in cerebellar ataxia akin to levodopa for Parkinson's disease.
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Affiliation(s)
- Haoran Huang
- Medical Scientist Training Program, The Ohio State University College of Medicine, Columbus, OH 43210, USA
| | - Vikram G Shakkottai
- Department of Neurology, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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7
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Pareek G. AAA+ proteases: the first line of defense against mitochondrial damage. PeerJ 2022; 10:e14350. [PMID: 36389399 PMCID: PMC9648348 DOI: 10.7717/peerj.14350] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 10/16/2022] [Indexed: 11/09/2022] Open
Abstract
Mitochondria play essential cellular roles in Adenosine triphosphate (ATP) synthesis, calcium homeostasis, and metabolism, but these vital processes have potentially deadly side effects. The production of the reactive oxygen species (ROS) and the aggregation of misfolded mitochondrial proteins can lead to severe mitochondrial damage and even cell death. The accumulation of mitochondrial damage is strongly implicated in aging and several incurable diseases, including neurodegenerative disorders and cancer. To oppose this, metazoans utilize a variety of quality control strategies, including the degradation of the damaged mitochondrial proteins by the mitochondrial-resident proteases of the ATPase Associated with the diverse cellular Activities (AAA+) family. This mini-review focuses on the quality control mediated by the mitochondrial-resident proteases of the AAA+ family used to combat the accumulation of damaged mitochondria and on how the failure of this mitochondrial quality control contributes to diseases.
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8
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Strachan EL, Mac White-Begg D, Crean J, Reynolds AL, Kennedy BN, O'Sullivan NC. The Role of Mitochondria in Optic Atrophy With Autosomal Inheritance. Front Neurosci 2021; 15:784987. [PMID: 34867178 PMCID: PMC8634724 DOI: 10.3389/fnins.2021.784987] [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: 09/28/2021] [Accepted: 10/22/2021] [Indexed: 11/13/2022] Open
Abstract
Optic atrophy (OA) with autosomal inheritance is a form of optic neuropathy characterized by the progressive and irreversible loss of vision. In some cases, this is accompanied by additional, typically neurological, extra-ocular symptoms. Underlying the loss of vision is the specific degeneration of the retinal ganglion cells (RGCs) which form the optic nerve. Whilst autosomal OA is genetically heterogenous, all currently identified causative genes appear to be associated with mitochondrial organization and function. However, it is unclear why RGCs are particularly vulnerable to mitochondrial aberration. Despite the relatively high prevalence of this disorder, there are currently no approved treatments. Combined with the lack of knowledge concerning the mechanisms through which aberrant mitochondrial function leads to RGC death, there remains a clear need for further research to identify the underlying mechanisms and develop treatments for this condition. This review summarizes the genes known to be causative of autosomal OA and the mitochondrial dysfunction caused by pathogenic mutations. Furthermore, we discuss the suitability of available in vivo models for autosomal OA with regards to both treatment development and furthering the understanding of autosomal OA pathology.
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Affiliation(s)
- Elin L Strachan
- UCD Conway Institute, University College Dublin, Dublin, Ireland.,UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Delphi Mac White-Begg
- UCD Conway Institute, University College Dublin, Dublin, Ireland.,UCD School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - John Crean
- UCD Conway Institute, University College Dublin, Dublin, Ireland.,UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland.,UCD Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Alison L Reynolds
- UCD Conway Institute, University College Dublin, Dublin, Ireland.,UCD School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - Breandán N Kennedy
- UCD Conway Institute, University College Dublin, Dublin, Ireland.,UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Niamh C O'Sullivan
- UCD Conway Institute, University College Dublin, Dublin, Ireland.,UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
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9
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Cendelin J, Cvetanovic M, Gandelman M, Hirai H, Orr HT, Pulst SM, Strupp M, Tichanek F, Tuma J, Manto M. Consensus Paper: Strengths and Weaknesses of Animal Models of Spinocerebellar Ataxias and Their Clinical Implications. THE CEREBELLUM 2021; 21:452-481. [PMID: 34378174 DOI: 10.1007/s12311-021-01311-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/21/2021] [Indexed: 01/02/2023]
Abstract
Spinocerebellar ataxias (SCAs) represent a large group of hereditary degenerative diseases of the nervous system, in particular the cerebellum, and other systems that manifest with a variety of progressive motor, cognitive, and behavioral deficits with the leading symptom of cerebellar ataxia. SCAs often lead to severe impairments of the patient's functioning, quality of life, and life expectancy. For SCAs, there are no proven effective pharmacotherapies that improve the symptoms or substantially delay disease progress, i.e., disease-modifying therapies. To study SCA pathogenesis and potential therapies, animal models have been widely used and are an essential part of pre-clinical research. They mainly include mice, but also other vertebrates and invertebrates. Each animal model has its strengths and weaknesses arising from model animal species, type of genetic manipulation, and similarity to human diseases. The types of murine and non-murine models of SCAs, their contribution to the investigation of SCA pathogenesis, pathological phenotype, and therapeutic approaches including their advantages and disadvantages are reviewed in this paper. There is a consensus among the panel of experts that (1) animal models represent valuable tools to improve our understanding of SCAs and discover and assess novel therapies for this group of neurological disorders characterized by diverse mechanisms and differential degenerative progressions, (2) thorough phenotypic assessment of individual animal models is required for studies addressing therapeutic approaches, (3) comparative studies are needed to bring pre-clinical research closer to clinical trials, and (4) mouse models complement cellular and invertebrate models which remain limited in terms of clinical translation for complex neurological disorders such as SCAs.
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Affiliation(s)
- Jan Cendelin
- Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic. .,Laboratory of Neurodegenerative Disorders, Biomedical Center, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic.
| | - Marija Cvetanovic
- Department of Neuroscience, Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Mandi Gandelman
- Department of Neurology, University of Utah, 175 North Medical Drive East, Salt Lake City, UT, 84132, USA
| | - Hirokazu Hirai
- Department of Neurophysiology and Neural Repair, Gunma University Graduate School of Medicine, 3-39-22, Gunma, 371-8511, Japan.,Viral Vector Core, Gunma University Initiative for Advanced Research (GIAR), Gunma, 371-8511, Japan
| | - Harry T Orr
- Department of Laboratory Medicine and Pathology, Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Stefan M Pulst
- Department of Neurology, University of Utah, 175 North Medical Drive East, Salt Lake City, UT, 84132, USA
| | - Michael Strupp
- Department of Neurology and German Center for Vertigo and Balance Disorders, Hospital of the Ludwig-Maximilians University, Munich, Campus Grosshadern, Marchioninistr. 15, 81377, Munich, Germany
| | - Filip Tichanek
- Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic.,Laboratory of Neurodegenerative Disorders, Biomedical Center, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic
| | - Jan Tuma
- Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic.,The Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MC 7843, San Antonio, TX, 78229, USA
| | - Mario Manto
- Unité des Ataxies Cérébelleuses, Service de Neurologie, CHU-Charleroi, Charleroi, Belgium.,Service des Neurosciences, Université de Mons, UMons, Mons, Belgium
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Chiang HL, Fuh JL, Tsai YS, Soong BW, Liao YC, Lee YC. Expanding the phenotype of AFG3L2 mutations: Late-onset autosomal recessive spinocerebellar ataxia. J Neurol Sci 2021; 428:117600. [PMID: 34333379 DOI: 10.1016/j.jns.2021.117600] [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: 04/18/2021] [Revised: 06/28/2021] [Accepted: 07/25/2021] [Indexed: 10/20/2022]
Abstract
The AFG3L2 gene encodes AFG3-like protein 2, which is a subunit of human mitochondrial ATPases associated with various cellular protease activities (m-AAA). The clinical spectrum of AFG3L2 mutations is broad. Dominant AFG3L2 mutations can cause autosomal dominant spinocerebellar ataxia type 28 (SCA28), whereas biallelic AFG3L2 mutations may lead to spastic ataxia 5 (SPAX5). However, the role of AFG3L2 mutations in autosomal recessive spinocerebellar ataxia (SCAR) remains elusive. The aim of this study is to delineate the clinical features and spectrum of AFG3L2 mutations in a Taiwanese cohort with cerebellar ataxia. Mutational analyses of AFG3L2 were carried out by targeted resequencing in a cohort of 133 unrelated patients with molecularly undetermined cerebellar ataxia. We identified one single patient carrying compound heterozygous mutations in AFG3L2, p.[R632*];[V723M] (c.[1894C > T];[2167G > A]). The patient has suffered from apparently sporadic and slowly progressive cerebellar ataxia, ptosis, and ophthalmoparesis since age 55 years. These findings expand the clinical spectrum of AFG3L2 mutations and suggest a new subtype of late-onset SCAR caused by biallelic AFG3L2 mutations.
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Affiliation(s)
- Han-Lin Chiang
- Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, No.201, Sec.2, Shipai Rd., Beitou District, Taipei, Taiwan; School of Medicine, National Yang Ming Chiao Tung University College of Medicine, No.155, Sec.2, Linong Street, Taipei, Taiwan
| | - Jong-Ling Fuh
- Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, No.201, Sec.2, Shipai Rd., Beitou District, Taipei, Taiwan; School of Medicine, National Yang Ming Chiao Tung University College of Medicine, No.155, Sec.2, Linong Street, Taipei, Taiwan; Brain Research Center, National Yang Ming Chiao Tung University School of Medicine. No.155, Sec.2, Linong Street, Taipei, Taiwan
| | - Yu-Shuen Tsai
- Center for Systems and Synthetic Biology, National Yang Ming Chiao Tung University, No.155, Sec.2, Linong Street, Taipei, Taiwan
| | - Bing-Wen Soong
- Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, No.201, Sec.2, Shipai Rd., Beitou District, Taipei, Taiwan; Department of Neurology, Shuang Ho Hospital, Taipei Medical University, No.291, Zhongzheng Rd., Zhonghe District, New Taipei 23561, Taiwan; Taipei Neuroscience Institute, Taipei Medical University, 250 Wu-Hsing Street, Taipei, Taiwan
| | - Yi-Chu Liao
- Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, No.201, Sec.2, Shipai Rd., Beitou District, Taipei, Taiwan; School of Medicine, National Yang Ming Chiao Tung University College of Medicine, No.155, Sec.2, Linong Street, Taipei, Taiwan; Brain Research Center, National Yang Ming Chiao Tung University School of Medicine. No.155, Sec.2, Linong Street, Taipei, Taiwan
| | - Yi-Chung Lee
- Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, No.201, Sec.2, Shipai Rd., Beitou District, Taipei, Taiwan; School of Medicine, National Yang Ming Chiao Tung University College of Medicine, No.155, Sec.2, Linong Street, Taipei, Taiwan; Brain Research Center, National Yang Ming Chiao Tung University School of Medicine. No.155, Sec.2, Linong Street, Taipei, Taiwan.
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11
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Pareek G, Pallanck LJ. Inactivation of the mitochondrial protease Afg3l2 results in severely diminished respiratory chain activity and widespread defects in mitochondrial gene expression. PLoS Genet 2020; 16:e1009118. [PMID: 33075064 PMCID: PMC7595625 DOI: 10.1371/journal.pgen.1009118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 10/29/2020] [Accepted: 09/15/2020] [Indexed: 11/18/2022] Open
Abstract
The m-AAA proteases play a critical role in the proteostasis of inner mitochondrial membrane proteins, and mutations in the genes encoding these proteases cause severe incurable neurological diseases. To further explore the biological role of the m-AAA proteases and the pathological consequences of their deficiency, we used a genetic approach in the fruit fly Drosophila melanogaster to inactivate the ATPase family gene 3-like 2 (AFG3L2) gene, which encodes a critical component of the m-AAA proteases. We found that null alleles of Drosophila AFG3L2 die early in development, but partial inactivation of AFG3L2 using RNAi allowed survival to the late pupal and adult stages of development. Flies with partial inactivation of AFG3L2 exhibited behavioral defects, neurodegeneration, accumulation of unfolded mitochondrial proteins, and diminished respiratory chain (RC) activity. Further work revealed that the reduced RC activity was primarily a consequence of severely diminished mitochondrial transcription and translation. These defects were accompanied by activation of the mitochondrial unfolded protein response (mito-UPR) and autophagy. Overexpression of mito-UPR components partially rescued the AFG3L2-deficient phenotypes, indicating that protein aggregation partly accounts for the defects of AFG3L2-deficient animals. Our work suggests that strategies designed to activate mitochondrial stress pathways and mitochondrial gene expression could be therapeutic in the diseases caused by mutations in AFG3L2.
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Affiliation(s)
- Gautam Pareek
- Department of Genome Sciences, University of Washington, Seattle, United States of America
| | - Leo J. Pallanck
- Department of Genome Sciences, University of Washington, Seattle, United States of America
- * E-mail:
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12
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Sambri I, Massa F, Gullo F, Meneghini S, Cassina L, Carraro M, Dina G, Quattrini A, Patanella L, Carissimo A, Iuliano A, Santorelli F, Codazzi F, Grohovaz F, Bernardi P, Becchetti A, Casari G. Impaired flickering of the permeability transition pore causes SPG7 spastic paraplegia. EBioMedicine 2020; 61:103050. [PMID: 33045469 PMCID: PMC7553352 DOI: 10.1016/j.ebiom.2020.103050] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 09/14/2020] [Accepted: 09/22/2020] [Indexed: 02/07/2023] Open
Abstract
Background Mutations of the mitochondrial protein paraplegin cause hereditary spastic paraplegia type 7 (SPG7), a so-far untreatable degenerative disease of the upper motoneuron with still undefined pathomechanism. The intermittent mitochondrial permeability transition pore (mPTP) opening, called flickering, is an essential process that operates to maintain mitochondrial homeostasis by reducing intra-matrix Ca2+ and reactive oxygen species (ROS) concentration, and is critical for efficient synaptic function. Methods We use a fluorescence-based approach to measure mPTP flickering in living cells and biochemical and molecular biology techniques to dissect the pathogenic mechanism of SPG7. In the SPG7 animal model we evaluate the potential improvement of the motor defect, neuroinflammation and neurodegeneration by means of an mPTP inducer, the benzodiazepine Bz-423. Findings We demonstrate that paraplegin is required for efficient transient opening of the mPTP, that is impaired in both SPG7 patients-derived fibroblasts and primary neurons from Spg7−/− mice. We show that dysregulation of mPTP opening at the pre-synaptic terminal impairs neurotransmitter release leading to ineffective synaptic transmission. Lack of paraplegin impairs mPTP flickering by a mechanism involving increased expression and activity of sirtuin3, which promotes deacetylation of cyclophilin D, thus hampering mPTP opening. Pharmacological treatment with Bz-423, which bypasses the activity of CypD, normalizes synaptic transmission and rescues the motor impairment of the SPG7 mouse model. Interpretation mPTP targeting opens a new avenue for the potential therapy of this form of spastic paraplegia. Funding Telethon Foundation grant (TGMGCSBX16TT); Dept. of Defense, US Army, grant W81XWH-18–1–0001
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Affiliation(s)
- Irene Sambri
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli-Naples, Italy
| | - Filomena Massa
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli-Naples, Italy
| | | | | | | | | | | | | | - Lorenzo Patanella
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli-Naples, Italy
| | - Annamaria Carissimo
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli-Naples, Italy; Institute for Applied Mathematics 'Mauro Picone', National Research Council, Naples, Italy
| | - Antonella Iuliano
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli-Naples, Italy
| | | | | | | | | | | | - Giorgio Casari
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli-Naples, Italy; Vita-Salute San Raffaele University, Milan, Italy.
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13
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Abstract
Mitochondria are essential organelles in eukaryotes. Most mitochondrial proteins are encoded by the nuclear genome and translated in the cytosol. Nuclear-encoded mitochondrial proteins need to be imported, processed, folded, and assembled into their functional states. To maintain protein homeostasis (proteostasis), mitochondria are equipped with a distinct set of quality control machineries. Deficiencies in such systems lead to mitochondrial dysfunction, which is a hallmark of aging and many human diseases, such as neurodegenerative diseases, cardiovascular diseases, and cancer. In this review, we discuss the unique challenges and solutions of proteostasis in mitochondria. The import machinery coordinates with mitochondrial proteases and chaperones to maintain the mitochondrial proteome. Moreover, mitochondrial proteostasis depends on cytosolic protein quality control mechanisms during crises. In turn, mitochondria facilitate cytosolic proteostasis. Increasing evidence suggests that enhancing mitochondrial proteostasis may hold therapeutic potential to protect against protein aggregation-associated cellular defects.
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Affiliation(s)
- Linhao Ruan
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA; , , , , ,
- Biochemistry, Cellular and Molecular Biology (BCMB) Graduate Program, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Yuhao Wang
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA; , , , , ,
- Biochemistry, Cellular and Molecular Biology (BCMB) Graduate Program, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Xi Zhang
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA; , , , , ,
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Alexis Tomaszewski
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA; , , , , ,
- Biochemistry, Cellular and Molecular Biology (BCMB) Graduate Program, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Joshua T McNamara
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA; , , , , ,
- Biochemistry, Cellular and Molecular Biology (BCMB) Graduate Program, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Rong Li
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA; , , , , ,
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
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14
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Lalonde R, Strazielle C. Motor Performances of Spontaneous and Genetically Modified Mutants with Cerebellar Atrophy. THE CEREBELLUM 2019; 18:615-634. [PMID: 30820866 DOI: 10.1007/s12311-019-01017-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Chance discovery of spontaneous mutants with atrophy of the cerebellar cortex has unearthed genes involved in optimizing motor coordination. Rotorod, stationary beam, and suspended wire tests are useful in delineating behavioral phenotypes of spontaneous mutants with cerebellar atrophy such as Grid2Lc, Grid2ho, Rorasg, Agtpbp1pcd, Relnrl, and Dab1scm. Likewise, transgenic or null mutants serving as experimental models of spinocerebellar ataxia (SCA) are phenotyped with the same tests. Among experimental models of autosomal dominant SCA, rotorod deficits were reported in SCA1 to 3, SCA5 to 8, SCA14, SCA17, and SCA27 and stationary beam deficits in SCA1 to 3, SCA5, SCA6, SCA13, SCA17, and SCA27. Beam tests are sensitive to experimental therapies of various kinds including molecules affecting glutamate signaling, mesenchymal stem cells, anti-oligomer antibodies, lentiviral vectors carrying genes, interfering RNAs, or neurotrophic factors, and interbreeding with other mutants.
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Affiliation(s)
- Robert Lalonde
- Department of Psychology, University of Rouen, 76821, Mont-Saint-Aignan Cedex, France.
| | - Catherine Strazielle
- Laboratory of Stress, Immunity, and Pathogens EA7300, and CHRU of Nancy, University of Lorraine, 54500, Vandoeuvre-les-Nancy, France
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15
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Ripolone M, Lucchini V, Ronchi D, Fagiolari G, Bordoni A, Fortunato F, Mondello S, Bonato S, Meregalli M, Torrente Y, Corti S, Comi GP, Moggio M, Sciacco M. Purkinje cell COX deficiency and mtDNA depletion in an animal model of spinocerebellar ataxia type 1. J Neurosci Res 2019; 96:1576-1585. [PMID: 30113722 DOI: 10.1002/jnr.24263] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/09/2018] [Accepted: 05/09/2018] [Indexed: 12/19/2022]
Abstract
Spinocerebellar ataxias (SCAs) are a genetically heterogeneous group of cerebellar degenerative disorders, characterized by progressive gait unsteadiness, hand incoordination, and dysarthria. Ataxia type 1 (SCA1) is caused by the expansion of a CAG trinucleotide repeat in the SCA1 gene resulting in the atypical extension of a polyglutamine (polyQ) tract within the ataxin-1 protein. Our main objective was to investigate the mitochondrial oxidative metabolism in the cerebellum of transgenic SCA1 mice. SCA1 transgenic mice develop clinical features in the early life stages (around 5 weeks of age) presenting pathological cerebellar signs with concomitant progressive Purkinje neuron atrophy and relatively little cell loss; this evidence suggests that the SCA1 phenotype is not the result of cell death per se, but a possible effect of cellular dysfunction that occurs before neuronal demise. We studied the mitochondrial oxidative metabolism in cerebellar cells from both homozygous and heterozygous transgenic SCA1 mice, aged 2 and 6 months. Histochemical examination showed a cytochrome-c-oxidase (COX) deficiency in the Purkinje cells (PCs) of both heterozygous and homozygous mice, the oxidative defect being more prominent in older mice, in which the percentage of COX-deficient PC was up to 30%. Using a laser-microdissector, we evaluated the mitochondrial DNA (mtDNA) content on selectively isolated COX-competent and COX-deficient PC by quantitative Polymerase Chain Reaction and we found mtDNA depletion in those with oxidative dysfunction. In conclusion, the selective oxidative metabolism defect observed in neuronal PC expressing mutant ataxin occurs as early as 8 weeks of age thus representing an early step in the PC degeneration process in SCA1 disease.
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Affiliation(s)
- Michela Ripolone
- Neuromuscular and Rare Diseases Unit, Department of Neuroscience, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Valeria Lucchini
- Neuromuscular and Rare Diseases Unit, Department of Neuroscience, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Dario Ronchi
- Neurology Unit, Neuroscience Section, Department of Pathophysiology and Transplantation, Dino Ferrari Centre, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Gigliola Fagiolari
- Neuromuscular and Rare Diseases Unit, Department of Neuroscience, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Andreina Bordoni
- Neurology Unit, Neuroscience Section, Department of Pathophysiology and Transplantation, Dino Ferrari Centre, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Francesco Fortunato
- Neurology Unit, Neuroscience Section, Department of Pathophysiology and Transplantation, Dino Ferrari Centre, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Stefania Mondello
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina, Italy
| | - Sara Bonato
- Neurology Unit, Neuroscience Section, Department of Pathophysiology and Transplantation, Dino Ferrari Centre, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Mirella Meregalli
- Department of Pathophysiology and Transplantation, Stem Cell Laboratory, Università degli Studi di Milano, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico di Milano, Centro Dino Ferrari, Milan, Italy
| | - Yvan Torrente
- Department of Pathophysiology and Transplantation, Stem Cell Laboratory, Università degli Studi di Milano, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico di Milano, Centro Dino Ferrari, Milan, Italy
| | - Stefania Corti
- Neurology Unit, Neuroscience Section, Department of Pathophysiology and Transplantation, Dino Ferrari Centre, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Giacomo P Comi
- Neurology Unit, Neuroscience Section, Department of Pathophysiology and Transplantation, Dino Ferrari Centre, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Maurizio Moggio
- Neuromuscular and Rare Diseases Unit, Department of Neuroscience, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Monica Sciacco
- Neuromuscular and Rare Diseases Unit, Department of Neuroscience, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
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16
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Upregulation of Peroxiredoxin 3 Protects Afg3l2-KO Cortical Neurons In Vitro from Oxidative Stress: A Paradigm for Neuronal Cell Survival under Neurodegenerative Conditions. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:4721950. [PMID: 31781336 PMCID: PMC6875171 DOI: 10.1155/2019/4721950] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 09/03/2019] [Accepted: 09/14/2019] [Indexed: 02/03/2023]
Abstract
Several neurodegenerative disorders exhibit selective vulnerability, with subsets of
neurons more affected than others, possibly because of the high expression of an altered
gene or the presence of particular features that make them more susceptible to insults. On
the other hand, resilient neurons may display the ability to develop antioxidant defenses,
particularly in diseases of mitochondrial origin, where oxidative stress might contribute
to the neurodegenerative process. In this work, we investigated the oxidative stress
response of embryonic fibroblasts and cortical neurons obtained from
Afg3l2-KO mice. AFG3L2 encodes a subunit of a protease
complex that is expressed in mitochondria and acts as both quality control and regulatory
enzyme affecting respiration and mitochondrial dynamics. When cells were subjected to an
acute oxidative stress protocol, the survival of AFG3L2-KO MEFs was not significantly
influenced and was comparable to that of WT; however, the basal level of the antioxidant
molecule glutathione was higher. Indeed, glutathione depletion strongly affected the
viability of KO, but not of WT MEF, thereby indicating that oxidative stress is more
elevated in KO MEF even though well controlled by glutathione. On the other hand, when
cortical KO neurons were put in culture, they immediately appeared more vulnerable than WT
to the acute oxidative stress condition, but after few days in vitro, the situation was
reversed with KO neurons being more resistant than WT to acute stress. This compensatory,
protective competence was not due to the upregulation of glutathione, rather of two
mitochondrial antioxidant proteins: superoxide dismutase 2 and, at an even higher level,
peroxiredoxin 3. This body of evidence sheds light on the capability of neurons to
activate neuroprotective pathways and points the attention to peroxiredoxin 3, an
antioxidant enzyme that might be critical for neuronal survival also in other disorders
affecting mitochondria.
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17
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Puchades C, Ding B, Song A, Wiseman RL, Lander GC, Glynn SE. Unique Structural Features of the Mitochondrial AAA+ Protease AFG3L2 Reveal the Molecular Basis for Activity in Health and Disease. Mol Cell 2019; 75:1073-1085.e6. [PMID: 31327635 PMCID: PMC6731152 DOI: 10.1016/j.molcel.2019.06.016] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 04/24/2019] [Accepted: 06/13/2019] [Indexed: 12/23/2022]
Abstract
Mitochondrial AAA+ quality-control proteases regulate diverse aspects of mitochondrial biology through specialized protein degradation, but the underlying mechanisms of these enzymes remain poorly defined. The mitochondrial AAA+ protease AFG3L2 is of particular interest, as genetic mutations localized throughout AFG3L2 are linked to diverse neurodegenerative disorders. However, a lack of structural data has limited our understanding of how mutations impact enzymatic function. Here, we used cryoelectron microscopy (cryo-EM) to determine a substrate-bound structure of the catalytic core of human AFG3L2. This structure identifies multiple specialized structural features that integrate with conserved motifs required for ATP-dependent translocation to unfold and degrade targeted proteins. Many disease-relevant mutations localize to these unique structural features of AFG3L2 and distinctly influence its activity and stability. Our results provide a molecular basis for neurological phenotypes associated with different AFG3L2 mutations and establish a structural framework to understand how different members of the AAA+ superfamily achieve specialized biological functions.
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Affiliation(s)
- Cristina Puchades
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA; Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA; Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Bojian Ding
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Albert Song
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA; Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA; Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - R Luke Wiseman
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Gabriel C Lander
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
| | - Steven E Glynn
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA.
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18
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Sprenger HG, Wani G, Hesseling A, König T, Patron M, MacVicar T, Ahola S, Wai T, Barth E, Rugarli EI, Bergami M, Langer T. Loss of the mitochondrial i-AAA protease YME1L leads to ocular dysfunction and spinal axonopathy. EMBO Mol Med 2019; 11:emmm.201809288. [PMID: 30389680 PMCID: PMC6328943 DOI: 10.15252/emmm.201809288] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Disturbances in the morphology and function of mitochondria cause neurological diseases, which can affect the central and peripheral nervous system. The i‐AAA protease YME1L ensures mitochondrial proteostasis and regulates mitochondrial dynamics by processing of the dynamin‐like GTPase OPA1. Mutations in YME1L cause a multi‐systemic mitochondriopathy associated with neurological dysfunction and mitochondrial fragmentation but pathogenic mechanisms remained enigmatic. Here, we report on striking cell‐type‐specific defects in mice lacking YME1L in the nervous system. YME1L‐deficient mice manifest ocular dysfunction with microphthalmia and cataracts and develop deficiencies in locomotor activity due to specific degeneration of spinal cord axons, which relay proprioceptive signals from the hind limbs to the cerebellum. Mitochondrial fragmentation occurs throughout the nervous system and does not correlate with the degenerative phenotype. Deletion of Oma1 restores tubular mitochondria but deteriorates axonal degeneration in the absence of YME1L, demonstrating that impaired mitochondrial proteostasis rather than mitochondrial fragmentation causes the observed neurological defects.
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Affiliation(s)
- Hans-Georg Sprenger
- Max-Planck-Institute for Biology of Ageing, Cologne, Germany.,Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Gulzar Wani
- Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Annika Hesseling
- Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Tim König
- Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Maria Patron
- Max-Planck-Institute for Biology of Ageing, Cologne, Germany.,Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Thomas MacVicar
- Max-Planck-Institute for Biology of Ageing, Cologne, Germany.,Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Sofia Ahola
- Max-Planck-Institute for Biology of Ageing, Cologne, Germany.,Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Timothy Wai
- Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Esther Barth
- Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Elena I Rugarli
- Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Matteo Bergami
- Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Center for Molecular Medicine, University of Cologne, Cologne, Germany
| | - Thomas Langer
- Max-Planck-Institute for Biology of Ageing, Cologne, Germany .,Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Center for Molecular Medicine, University of Cologne, Cologne, Germany
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19
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Abstract
Mitochondria are metabolic hubs that use multiple proteases to maintain proteostasis and to preserve their overall quality. A decline of mitochondrial proteolysis promotes cellular stress and may contribute to the aging process. Mitochondrial proteases have also emerged as tightly regulated enzymes required to support the remarkable mitochondrial plasticity necessary for metabolic adaptation in a number of physiological scenarios. Indeed, the mutation and dysfunction of several mitochondrial proteases can cause specific human diseases with severe metabolic phenotypes. Here, we present an overview of the proteolytic regulation of key mitochondrial functions such as respiration, lipid biosynthesis, and mitochondrial dynamics, all of which are required for metabolic control. We also pay attention to how mitochondrial proteases are acutely regulated in response to cellular stressors or changes in growth conditions, a greater understanding of which may one day uncover their therapeutic potential.
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Murru S, Hess S, Barth E, Almajan ER, Schatton D, Hermans S, Brodesser S, Langer T, Kloppenburg P, Rugarli EI. Astrocyte-specific deletion of the mitochondrial m-AAA protease reveals glial contribution to neurodegeneration. Glia 2019; 67:1526-1541. [PMID: 30989755 PMCID: PMC6618114 DOI: 10.1002/glia.23626] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 04/02/2019] [Accepted: 04/04/2019] [Indexed: 12/15/2022]
Abstract
Mitochondrial dysfunction causes neurodegeneration but whether impairment of mitochondrial homeostasis in astrocytes contributes to this pathological process remains largely unknown. The m‐AAA protease exerts quality control and regulatory functions crucial for mitochondrial homeostasis. AFG3L2, which encodes one of the subunits of the m‐AAA protease, is mutated in spinocerebellar ataxia SCA28 and in infantile syndromes characterized by spastic‐ataxia, epilepsy and premature death. Here, we investigate the role of Afg3l2 and its redundant homologue Afg3l1 in the Bergmann glia (BG), radial astrocytes of the cerebellum that have functional connections with Purkinje cells (PC) and regulate glutamate homeostasis. We show that astrocyte‐specific deletion of Afg3l2 in the mouse leads to late‐onset motor impairment and to degeneration of BG, which display aberrant morphology, altered expression of the glutamate transporter EAAT2, and a reactive inflammatory signature. The neurological and glial phenotypes are drastically exacerbated when astrocytes lack both Afg31l and Afg3l2, and therefore, are totally depleted of the m‐AAA protease. Moreover, mitochondrial stress responses and necroptotic markers are induced in the cerebellum. In both mouse models, targeted BG show a fragmented mitochondrial network and loss of mitochondrial cristae, but no signs of respiratory dysfunction. Importantly, astrocyte‐specific deficiency of Afg3l1 and Afg3l2 triggers secondary morphological degeneration and electrophysiological changes in PCs, thus demonstrating a non‐cell‐autonomous role of glia in neurodegeneration. We propose that astrocyte dysfunction amplifies both neuroinflammation and glutamate excitotoxicity in patients carrying mutations in AFG3L2, leading to a vicious circle that contributes to neuronal death.
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Affiliation(s)
- Sara Murru
- Department of Biology, Institute for Genetics, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Simon Hess
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Department of Biology, Institute for Zoology, Biocenter, University of Cologne, Cologne, Germany
| | - Esther Barth
- Department of Biology, Institute for Genetics, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Eva R Almajan
- Department of Biology, Institute for Genetics, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Désirée Schatton
- Department of Biology, Institute for Genetics, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Steffen Hermans
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Susanne Brodesser
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Thomas Langer
- Department of Mitochondrial Proteostasis, Max-Planck-Institute for Biology of Ageing, Cologne, Germany
| | - Peter Kloppenburg
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Department of Biology, Institute for Zoology, Biocenter, University of Cologne, Cologne, Germany
| | - Elena I Rugarli
- Department of Biology, Institute for Genetics, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
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21
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Tulli S, Del Bondio A, Baderna V, Mazza D, Codazzi F, Pierson TM, Ambrosi A, Nolte D, Goizet C, Toro C, Baets J, Deconinck T, DeJonghe P, Mandich P, Casari G, Maltecca F. Pathogenic variants in the AFG3L2 proteolytic domain cause SCA28 through haploinsufficiency and proteostatic stress-driven OMA1 activation. J Med Genet 2019; 56:499-511. [PMID: 30910913 PMCID: PMC6678042 DOI: 10.1136/jmedgenet-2018-105766] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 02/05/2019] [Accepted: 03/03/2019] [Indexed: 12/18/2022]
Abstract
Background Spinocerebellar ataxia type 28 (SCA28) is a dominantly inherited neurodegenerative disease caused by pathogenic variants in AFG3L2. The AFG3L2 protein is a subunit of mitochondrial m-AAA complexes involved in protein quality control. Objective of this study was to determine the molecular mechanisms of SCA28, which has eluded characterisation to date. Methods We derived SCA28 patient fibroblasts carrying different pathogenic variants in the AFG3L2 proteolytic domain (missense: the newly identified p.F664S and p.M666T, p.G671R, p.Y689H and a truncating frameshift p.L556fs) and analysed multiple aspects of mitochondrial physiology. As reference of residual m-AAA activity, we included SPAX5 patient fibroblasts with homozygous p.Y616C pathogenic variant, AFG3L2+/− HEK293 T cells by CRISPR/Cas9-genome editing and Afg3l2−/− murine fibroblasts. Results We found that SCA28 cells carrying missense changes have normal levels of assembled m-AAA complexes, while the cells with a truncating pathogenic variant had only half of this amount. We disclosed inefficient mitochondrial fusion in SCA28 cells caused by increased OPA1 processing operated by hyperactivated OMA1. Notably, we found altered mitochondrial proteostasis to be the trigger of OMA1 activation in SCA28 cells, with pharmacological attenuation of mitochondrial protein synthesis resulting in stabilised levels of OMA1 and OPA1 long forms, which rescued mitochondrial fusion efficiency. Secondary to altered mitochondrial morphology, mitochondrial calcium uptake resulted decreased in SCA28 cells. Conclusion Our data identify the earliest events in SCA28 pathogenesis and open new perspectives for therapy. By identifying similar mitochondrial phenotypes between SCA28 cells and AFG3L2+/− cells, our results support haploinsufficiency as the mechanism for the studied pathogenic variants.
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Affiliation(s)
- Susanna Tulli
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Andrea Del Bondio
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Valentina Baderna
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Davide Mazza
- Experimental Imaging Center, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Franca Codazzi
- Università Vita-Salute San Raffaele, Milan, Italy.,Division of Neuroscience, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Tyler Mark Pierson
- Departments of Pediatrics and Neurology and the Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | | | - Dagmar Nolte
- Department of Medicine, Institute for Human Genetics, Justus-Liebig-University Giessen, Giessen, Germany
| | - Cyril Goizet
- Centre de Reference Neurogenetique, Service de Genetique Medicale, CHU Bordeaux, Bordeaux, France.,Laboratoire MRGM, INSERM U1211, Bordeaux, France
| | - Camilo Toro
- Undiagnosed Disease Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, Maryland, USA
| | - Jonathan Baets
- Neurogenetics Group and Institute Born-Bunge, University of Antwerp, Antwerpen, Belgium.,Neuromuscular Reference Centre, Antwerp University Hospital, Antwerpen, Belgium
| | - Tine Deconinck
- Neurogenetics Group and Institute Born-Bunge, University of Antwerp, Antwerpen, Belgium.,Neuromuscular Reference Centre, Antwerp University Hospital, Antwerpen, Belgium
| | - Peter DeJonghe
- Neurogenetics Group and Institute Born-Bunge, University of Antwerp, Antwerpen, Belgium.,Neuromuscular Reference Centre, Antwerp University Hospital, Antwerpen, Belgium
| | - Paola Mandich
- DINOGMI, University of Genoa and IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Giorgio Casari
- Università Vita-Salute San Raffaele, Milan, Italy.,Telethon Institute of Genetics and Medicine, Naples, Italy
| | - Francesca Maltecca
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy.,Università Vita-Salute San Raffaele, Milan, Italy
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22
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Mancini C, Hoxha E, Iommarini L, Brussino A, Richter U, Montarolo F, Cagnoli C, Parolisi R, Gondor Morosini DI, Nicolò V, Maltecca F, Muratori L, Ronchi G, Geuna S, Arnaboldi F, Donetti E, Giorgio E, Cavalieri S, Di Gregorio E, Pozzi E, Ferrero M, Riberi E, Casari G, Altruda F, Turco E, Gasparre G, Battersby BJ, Porcelli AM, Ferrero E, Brusco A, Tempia F. Mice harbouring a SCA28 patient mutation in AFG3L2 develop late-onset ataxia associated with enhanced mitochondrial proteotoxicity. Neurobiol Dis 2018; 124:14-28. [PMID: 30389403 DOI: 10.1016/j.nbd.2018.10.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/05/2018] [Accepted: 10/28/2018] [Indexed: 12/20/2022] Open
Abstract
Spinocerebellar ataxia 28 is an autosomal dominant neurodegenerative disorder caused by missense mutations affecting the proteolytic domain of AFG3L2, a major component of the mitochondrial m-AAA protease. However, little is known of the underlying pathogenetic mechanisms or how to treat patients with SCA28. Currently available Afg3l2 mutant mice harbour deletions that lead to severe, early-onset neurological phenotypes that do not faithfully reproduce the late-onset and slowly progressing SCA28 phenotype. Here we describe production and detailed analysis of a new knock-in murine model harbouring an Afg3l2 allele carrying the p.Met665Arg patient-derived mutation. Heterozygous mutant mice developed normally but adult mice showed signs of cerebellar ataxia detectable by beam test. Although cerebellar pathology was negative, electrophysiological analysis showed a trend towards increased spontaneous firing in Purkinje cells from heterozygous mutants with respect to wild-type controls. As homozygous mutants died perinatally with evidence of cardiac atrophy, for each genotype we generated mouse embryonic fibroblasts (MEFs) to investigate mitochondrial function. MEFs from mutant mice showed altered mitochondrial bioenergetics, with decreased basal oxygen consumption rate, ATP synthesis and mitochondrial membrane potential. Mitochondrial network formation and morphology was altered, with greatly reduced expression of fusogenic Opa1 isoforms. Mitochondrial alterations were also detected in cerebella of 18-month-old heterozygous mutants and may be a hallmark of disease. Pharmacological inhibition of de novo mitochondrial protein translation with chloramphenicol caused reversal of mitochondrial morphology in homozygous mutant MEFs, supporting the relevance of mitochondrial proteotoxicity for SCA28 pathogenesis and therapy development.
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Affiliation(s)
- Cecilia Mancini
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Eriola Hoxha
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Luisa Iommarini
- Department of Pharmacy and Biotechnologies (FABIT), University of Bologna, Bologna, Italy
| | | | - Uwe Richter
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Francesca Montarolo
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Claudia Cagnoli
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Roberta Parolisi
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Diana Iulia Gondor Morosini
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Valentina Nicolò
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Francesca Maltecca
- Università Vita-Salute San Raffaele, Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Luisa Muratori
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy; Department of Clinical and Biological Sciences, University of Torino, Torino, Italy
| | - Giulia Ronchi
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy; Department of Clinical and Biological Sciences, University of Torino, Torino, Italy
| | - Stefano Geuna
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy; Department of Clinical and Biological Sciences, University of Torino, Torino, Italy
| | - Francesca Arnaboldi
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
| | - Elena Donetti
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
| | - Elisa Giorgio
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Simona Cavalieri
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Eleonora Di Gregorio
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Torino, Italy
| | - Elisa Pozzi
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Marta Ferrero
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Evelise Riberi
- Department of Public Health and Pediatrics, University of Torino, Torino, Italy
| | - Giorgio Casari
- Università Vita-Salute San Raffaele, Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Fiorella Altruda
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Emilia Turco
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Giuseppe Gasparre
- Department Medical and Surgical Sciences, Medical Genetics, University of Bologna, Bologna, Italy
| | | | - Anna Maria Porcelli
- Department of Pharmacy and Biotechnologies (FABIT), University of Bologna, Bologna, Italy
| | - Enza Ferrero
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Alfredo Brusco
- Department of Medical Sciences, University of Torino, Torino, Italy; Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Torino, Italy.
| | - Filippo Tempia
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
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23
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AAA Proteases: Guardians of Mitochondrial Function and Homeostasis. Cells 2018; 7:cells7100163. [PMID: 30314276 PMCID: PMC6210556 DOI: 10.3390/cells7100163] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 10/04/2018] [Accepted: 10/09/2018] [Indexed: 12/30/2022] Open
Abstract
Mitochondria are dynamic, semi-autonomous organelles that execute numerous life-sustaining tasks in eukaryotic cells. Functioning of mitochondria depends on the adequate action of versatile proteinaceous machineries. Fine-tuning of mitochondrial activity in response to cellular needs involves continuous remodeling of organellar proteome. This process not only includes modulation of various biogenetic pathways, but also the removal of superfluous proteins by adenosine triphosphate (ATP)-driven proteolytic machineries. Accordingly, all mitochondrial sub-compartments are under persistent surveillance of ATP-dependent proteases. Particularly important are highly conserved two inner mitochondrial membrane-bound metalloproteases known as m-AAA and i-AAA (ATPases associated with diverse cellular activities), whose mis-functioning may lead to impaired organellar function and consequently to development of severe diseases. Herein, we discuss the current knowledge of yeast, mammalian, and plant AAA proteases and their implications in mitochondrial function and homeostasis maintenance.
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24
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Magri S, Fracasso V, Plumari M, Alfei E, Ghezzi D, Gellera C, Rusmini P, Poletti A, Di Bella D, Elia AE, Pantaleoni C, Taroni F. Concurrent AFG3L2 and SPG7 mutations associated with syndromic parkinsonism and optic atrophy with aberrant OPA1 processing and mitochondrial network fragmentation. Hum Mutat 2018; 39:2060-2071. [PMID: 30252181 DOI: 10.1002/humu.23658] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 09/03/2018] [Accepted: 09/22/2018] [Indexed: 01/26/2023]
Abstract
Mitochondrial dynamics and quality control are crucial for neuronal survival and their perturbation is a major cause of neurodegeneration. m-AAA complex is an ATP-dependent metalloprotease located in the inner mitochondrial membrane and involved in protein quality control. Mutations in the m-AAA subunits AFG3L2 and paraplegin are associated with autosomal dominant spinocerebellar ataxia (SCA28) and autosomal recessive hereditary spastic paraplegia (SPG7), respectively. We report a novel m-AAA-associated phenotype characterized by early-onset optic atrophy with spastic ataxia and L-dopa-responsive parkinsonism. The proband carried a de novo AFG3L2 heterozygous mutation (p.R468C) along with a heterozygous maternally inherited intragenic deletion of SPG7. Functional analysis in yeast demonstrated the pathogenic role of AFG3L2 p.R468C mutation shedding light on its pathogenic mechanism. Analysis of patient's fibroblasts showed an abnormal processing pattern of OPA1, a dynamin-related protein essential for mitochondrial fusion and responsible for most cases of hereditary optic atrophy. Consistently, assessment of mitochondrial morphology revealed a severe fragmentation of the mitochondrial network, not observed in SCA28 and SPG7 patients' cells. This case suggests that coincidental mutations in both components of the mitochondrial m-AAA protease may result in a complex phenotype and reveals a crucial role for OPA1 processing in the pathogenesis of neurodegenerative disease caused by m-AAA defects.
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Affiliation(s)
- Stefania Magri
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Valentina Fracasso
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Massimo Plumari
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Enrico Alfei
- Unit of Developmental Neurology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Daniele Ghezzi
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.,Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - Cinzia Gellera
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Paola Rusmini
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Centro di Eccellenza sulle Malattie Neurodegenerative, Università degli Studi di Milano, Milan, Italy
| | - Angelo Poletti
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Centro di Eccellenza sulle Malattie Neurodegenerative, Università degli Studi di Milano, Milan, Italy
| | - Daniela Di Bella
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Antonio E Elia
- Unit of Neurology 1, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Chiara Pantaleoni
- Unit of Developmental Neurology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Franco Taroni
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
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25
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Ding B, Martin DW, Rampello AJ, Glynn SE. Dissecting Substrate Specificities of the Mitochondrial AFG3L2 Protease. Biochemistry 2018; 57:4225-4235. [PMID: 29932645 DOI: 10.1021/acs.biochem.8b00565] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Human AFG3L2 is a compartmental AAA+ protease that performs ATP-fueled degradation at the matrix face of the inner mitochondrial membrane. Identifying how AFG3L2 selects substrates from the diverse complement of matrix-localized proteins is essential for understanding mitochondrial protein biogenesis and quality control. Here, we create solubilized forms of AFG3L2 to examine the enzyme's substrate specificity mechanisms. We show that conserved residues within the presequence of the mitochondrial ribosomal protein, MrpL32, target the subunit to the protease for processing into a mature form. Moreover, these residues can act as a degron, delivering diverse model proteins to AFG3L2 for degradation. By determining the sequence of degradation products from multiple substrates using mass spectrometry, we construct a peptidase specificity profile that displays constrained product lengths and is dominated by the identity of the residue at the P1' position, with a strong preference for hydrophobic and small polar residues. This specificity profile is validated by examining the cleavage of both fluorogenic reporter peptides and full polypeptide substrates bearing different P1' residues. Together, these results demonstrate that AFG3L2 contains multiple modes of specificity, discriminating between potential substrates by recognizing accessible degron sequences and performing peptide bond cleavage at preferred patterns of residues within the compartmental chamber.
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26
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Lebeau J, Rainbolt TK, Wiseman RL. Coordinating Mitochondrial Biology Through the Stress-Responsive Regulation of Mitochondrial Proteases. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 340:79-128. [PMID: 30072094 PMCID: PMC6402875 DOI: 10.1016/bs.ircmb.2018.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Proteases are localized throughout mitochondria and function as critical regulators of all aspects of mitochondrial biology. As such, the activities of these proteases are sensitively regulated through transcriptional and post-translational mechanisms to adapt mitochondrial function to specific cellular demands. Here, we discuss the stress-responsive mechanisms responsible for regulating mitochondrial protease activity and the implications of this regulation on mitochondrial function. Furthermore, we describe how imbalances in the activity or regulation of mitochondrial proteases induced by genetic, environmental, or aging-related factors influence mitochondria in the context of disease. Understanding the molecular mechanisms by which cells regulate mitochondrial function through alterations in protease activity provide insights into the contributions of these proteases in pathologic mitochondrial dysfunction and reveals new therapeutic opportunities to ameliorate this dysfunction in the context of diverse classes of human disease.
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Affiliation(s)
- Justine Lebeau
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - T Kelly Rainbolt
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - R Luke Wiseman
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
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27
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Patron M, Sprenger HG, Langer T. m-AAA proteases, mitochondrial calcium homeostasis and neurodegeneration. Cell Res 2018; 28:296-306. [PMID: 29451229 PMCID: PMC5835776 DOI: 10.1038/cr.2018.17] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The function of mitochondria depends on ubiquitously expressed and evolutionary conserved m-AAA proteases in the inner membrane. These ATP-dependent peptidases form hexameric complexes built up of homologous subunits. AFG3L2 subunits assemble either into homo-oligomeric isoenzymes or with SPG7 (paraplegin) subunits into hetero-oligomeric proteolytic complexes. Mutations in AFG3L2 are associated with dominant spinocerebellar ataxia (SCA28) characterized by the loss of Purkinje cells, whereas mutations in SPG7 cause a recessive form of hereditary spastic paraplegia (HSP7) with motor neurons of the cortico-spinal tract being predominantly affected. Pleiotropic functions have been assigned to m-AAA proteases, which act as quality control and regulatory enzymes in mitochondria. Loss of m-AAA proteases affects mitochondrial protein synthesis and respiration and leads to mitochondrial fragmentation and deficiencies in the axonal transport of mitochondria. Moreover m-AAA proteases regulate the assembly of the mitochondrial calcium uniporter (MCU) complex. Impaired degradation of the MCU subunit EMRE in AFG3L2-deficient mitochondria results in the formation of deregulated MCU complexes, increased mitochondrial calcium uptake and increased vulnerability of neurons for calcium-induced cell death. A reduction of calcium influx into the cytosol of Purkinje cells rescues ataxia in an AFG3L2-deficient mouse model. In this review, we discuss the relationship between the m-AAA protease and mitochondrial calcium homeostasis and its relevance for neurodegeneration and describe a novel mouse model lacking MCU specifically in Purkinje cells. Our results pledge for a novel view on m-AAA proteases that integrates their pleiotropic functions in mitochondria to explain the pathogenesis of associated neurodegenerative disorders.
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Affiliation(s)
- Maria Patron
- Max Planck Institute for Biology of Aging, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Response in Aging-Associated Disease (CECAD), and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Hans-Georg Sprenger
- Max Planck Institute for Biology of Aging, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Response in Aging-Associated Disease (CECAD), and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Thomas Langer
- Max Planck Institute for Biology of Aging, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Response in Aging-Associated Disease (CECAD), and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
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28
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Volonte D, Liu Z, Shiva S, Galbiati F. Caveolin-1 controls mitochondrial function through regulation of m-AAA mitochondrial protease. Aging (Albany NY) 2017; 8:2355-2369. [PMID: 27705926 PMCID: PMC5115893 DOI: 10.18632/aging.101051] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 09/19/2016] [Indexed: 11/25/2022]
Abstract
Mitochondrial proteases ensure mitochondrial integrity and function after oxidative stress by providing mitochondrial protein quality control. However, the molecular mechanisms that regulate this basic biological function in eukaryotic cells remain largely unknown. Caveolin-1 is a scaffolding protein involved in signal transduction. We find that AFG3L2, a m-AAA type of mitochondrial protease, is a novel caveolin-1-interacting protein in vitro. We show that oxidative stress promotes the translocation of both caveolin-1 and AFG3L2 to mitochondria, enhances the interaction of caveolin-1 with AFG3L2 in mitochondria and stimulates mitochondrial protease activity in wild-type fibroblasts. Localization of AFG3L2 to mitochondria after oxidative stress is inhibited in fibroblasts lacking caveolin-1, which results in impaired mitochondrial protein quality control, an oxidative phosphorylation to aerobic glycolysis switch and reduced ATP production. Mechanistically, we demonstrate that a lack of caveolin-1 does not alter either mitochondrial number or morphology but leads to the cytoplasmic and proteasome-dependent degradation of complexes I, III, IV and V upon oxidant stimulation. Restoration of mitochondrial respiratory chain complexes in caveolin-1 null fibroblasts reverts the enhanced glycolysis observed in these cells. Expression of a mutant form of AFG3L2, which has reduced affinity for caveolin-1, fails to localize to mitochondria and promotes degradation of complex IV after oxidative stress. Thus, caveolin-1 maintains mitochondrial integrity and function when cells are challenged with free radicals by promoting the mitochondrial localization of m-AAA protease and its quality control functions.
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Affiliation(s)
- Daniela Volonte
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Zhongmin Liu
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Sruti Shiva
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.,Vascular Medicine Institute and Center for Metabolism and Mitochondrial Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Ferruccio Galbiati
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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Eskandrani A, AlHashem A, Ali ES, AlShahwan S, Tlili K, Hundallah K, Tabarki B. Recessive AFG3L2 Mutation Causes Progressive Microcephaly, Early Onset Seizures, Spasticity, and Basal Ganglia Involvement. Pediatr Neurol 2017; 71:24-28. [PMID: 28449981 DOI: 10.1016/j.pediatrneurol.2017.03.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 03/28/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND Mutations in AFG3L2, a gene encoding a subunit of the mitochondrion m-AAA protease, cause spinocerebellar ataxia type 28 and recessive spastic ataxia type 5. Neuroimaging shows cerebellar atrophy. METHODS Retrospective review of the patient charts including their clinical evaluation and molecular genetic, neurodiagnostic, and neuroradiological investigations. RESULTS We describe five members of a large consanguineous family with a severe mitochondrial disease phenotype in the form of regression of the developmental milestones in the first year of life, refractory epilepsy, progressive microcephaly, increased blood lactate, basal ganglia involvement, and premature death. Exome sequencing showed homozygous mutation of the AFG3L2 gene in all individuals: c.1714G>A (p.Ala572Thr). CONCLUSIONS Our findings add to the phenotypic, neuroradiological, genetic, and biochemical spectrum of AFG3L2 mutations.
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Affiliation(s)
- Alaa Eskandrani
- Division of Pediatric Neurology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Amal AlHashem
- Division of Pediatric Genetics, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - El-Sayed Ali
- Department of Pediatrics, King Fahad Military Medical Complex, Dhahran, Saudi Arabia
| | - Saad AlShahwan
- Division of Pediatric Neurology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Kalthoum Tlili
- Division of Neuroradiology, Department of Radiology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Khaled Hundallah
- Division of Pediatric Neurology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Brahim Tabarki
- Division of Pediatric Neurology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia.
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Glynn SE. Multifunctional Mitochondrial AAA Proteases. Front Mol Biosci 2017; 4:34. [PMID: 28589125 PMCID: PMC5438985 DOI: 10.3389/fmolb.2017.00034] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 05/08/2017] [Indexed: 11/28/2022] Open
Abstract
Mitochondria perform numerous functions necessary for the survival of eukaryotic cells. These activities are coordinated by a diverse complement of proteins encoded in both the nuclear and mitochondrial genomes that must be properly organized and maintained. Misregulation of mitochondrial proteostasis impairs organellar function and can result in the development of severe human diseases. ATP-driven AAA+ proteins play crucial roles in preserving mitochondrial activity by removing and remodeling protein molecules in accordance with the needs of the cell. Two mitochondrial AAA proteases, i-AAA and m-AAA, are anchored to either face of the mitochondrial inner membrane, where they engage and process an array of substrates to impact protein biogenesis, quality control, and the regulation of key metabolic pathways. The functionality of these proteases is extended through multiple substrate-dependent modes of action, including complete degradation, partial processing, or dislocation from the membrane without proteolysis. This review discusses recent advances made toward elucidating the mechanisms of substrate recognition, handling, and degradation that allow these versatile proteases to control diverse activities in this multifunctional organelle.
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Affiliation(s)
- Steven E Glynn
- Department of Biochemistry and Cell Biology, Stony Brook UniversityStony Brook, NY, United States
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31
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Batiuk MY, de Vin F, Duqué SI, Li C, Saito T, Saido T, Fiers M, Belgard TG, Holt MG. An immunoaffinity-based method for isolating ultrapure adult astrocytes based on ATP1B2 targeting by the ACSA-2 antibody. J Biol Chem 2017; 292:8874-8891. [PMID: 28373281 DOI: 10.1074/jbc.m116.765313] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 03/10/2017] [Indexed: 12/21/2022] Open
Abstract
Astrocytes are a major cell type in the mammalian CNS. Astrocytes are now known to play a number of essential roles in processes including synapse formation and function, as well as blood-brain barrier formation and control of cerebral blood flow. However, our understanding of the molecular mechanisms underlying astrocyte development and function is still rudimentary. This lack of knowledge is at least partly due to the lack of tools currently available for astrocyte biology. ACSA-2 is a commercially available antibody originally developed for the isolation of astrocytes from young postnatal mouse brain, using magnetic cell-sorting methods, but its utility in isolating cells from adult tissue has not yet been published. Using a modified protocol, we now show that this tool can also be used to isolate ultrapure astrocytes from the adult brain. Furthermore, using a variety of techniques (including single-cell sequencing, overexpression and knockdown assays, immunoblotting, and immunohistochemistry), we identify the ACSA-2 epitope for the first time as ATP1B2 and characterize its distribution in the CNS. Finally, we show that ATP1B2 is stably expressed in multiple models of CNS injury and disease. Hence, we show that the ACSA-2 antibody possesses the potential to be an extremely valuable tool for astrocyte research, allowing the purification and characterization of astrocytes (potentially including injury and disease models) without the need for any specialized and expensive equipment. In fact, our results suggest that ACSA-2 should be a first-choice method for astrocyte isolation and characterization.
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Affiliation(s)
- Mykhailo Y Batiuk
- From the Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research.,the Laboratory of Glia Biology, KU Leuven Department of Neuroscience, and
| | - Filip de Vin
- From the Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research.,the Laboratory of Glia Biology, KU Leuven Department of Neuroscience, and
| | - Sandra I Duqué
- From the Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research.,the Laboratory of Glia Biology, KU Leuven Department of Neuroscience, and
| | - Chen Li
- From the Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research.,the Laboratory of Glia Biology, KU Leuven Department of Neuroscience, and
| | - Takashi Saito
- the Laboratory for Proteolytic Neuroscience, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0106, Japan, and
| | - Takaomi Saido
- the Laboratory for Proteolytic Neuroscience, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0106, Japan, and
| | - Mark Fiers
- the VIB-KU Leuven Center for Brain and Disease Research, KU Leuven, Herestraat 49, B-3000 Leuven, Belgium
| | - T Grant Belgard
- the Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, South Parks Road, Oxford OX1 3PT, United Kingdom
| | - Matthew G Holt
- From the Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, .,the Laboratory of Glia Biology, KU Leuven Department of Neuroscience, and
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Wang S, Jacquemyn J, Murru S, Martinelli P, Barth E, Langer T, Niessen CM, Rugarli EI. The Mitochondrial m-AAA Protease Prevents Demyelination and Hair Greying. PLoS Genet 2016; 12:e1006463. [PMID: 27911893 PMCID: PMC5135034 DOI: 10.1371/journal.pgen.1006463] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 11/04/2016] [Indexed: 02/07/2023] Open
Abstract
The m-AAA protease preserves proteostasis of the inner mitochondrial membrane. It ensures a functional respiratory chain, by controlling the turnover of respiratory complex subunits and allowing mitochondrial translation, but other functions in mitochondria are conceivable. Mutations in genes encoding subunits of the m-AAA protease have been linked to various neurodegenerative diseases in humans, such as hereditary spastic paraplegia and spinocerebellar ataxia. While essential functions of the m-AAA protease for neuronal survival have been established, its role in adult glial cells remains enigmatic. Here, we show that deletion of the highly expressed subunit AFG3L2 in mature mouse oligodendrocytes provokes early-on mitochondrial fragmentation and swelling, as previously shown in neurons, but causes only late-onset motor defects and myelin abnormalities. In contrast, total ablation of the m-AAA protease, by deleting both Afg3l2 and its paralogue Afg3l1, triggers progressive motor dysfunction and demyelination, owing to rapid oligodendrocyte cell death. Surprisingly, the mice showed premature hair greying, caused by progressive loss of melanoblasts that share a common developmental origin with Schwann cells and are targeted in our experiments. Thus, while both neurons and glial cells are dependant on the m-AAA protease for survival in vivo, complete ablation of the complex is necessary to trigger death of oligodendrocytes, hinting to cell-autonomous thresholds of vulnerability to m-AAA protease deficiency.
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Affiliation(s)
- Shuaiyu Wang
- Institute for Genetics, University of Cologne, Cologne, Germany
| | - Julie Jacquemyn
- Institute for Genetics, University of Cologne, Cologne, Germany
| | - Sara Murru
- Institute for Genetics, University of Cologne, Cologne, Germany
| | | | - Esther Barth
- Institute for Genetics, University of Cologne, Cologne, Germany
| | - Thomas Langer
- Institute for Genetics, University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
| | - Carien M. Niessen
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
- Department of Dermatology, University of Cologne, Cologne, Germany
| | - Elena I. Rugarli
- Institute for Genetics, University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
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Levytskyy RM, Germany EM, Khalimonchuk O. Mitochondrial Quality Control Proteases in Neuronal Welfare. J Neuroimmune Pharmacol 2016; 11:629-644. [PMID: 27137937 PMCID: PMC5093085 DOI: 10.1007/s11481-016-9683-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 04/27/2016] [Indexed: 01/01/2023]
Abstract
The functional integrity of mitochondria is a critical determinant of neuronal health and compromised mitochondrial function is a commonly recognized factor that underlies a plethora of neurological and neurodegenerative diseases. Metabolic demands of neural cells require high bioenergetic outputs that are often associated with enhanced production of reactive oxygen species. Unopposed accumulation of these respiratory byproducts over time leads to oxidative damage and imbalanced protein homeostasis within mitochondrial subcompartments, which in turn may result in cellular demise. The post-mitotic nature of neurons and their vulnerability to these stress factors necessitate strict protein homeostatic control to prevent such scenarios. A series of evolutionarily conserved proteases is one of the central elements of mitochondrial quality control. These versatile proteolytic enzymes conduct a multitude of activities to preserve normal mitochondrial function during organelle biogenesis, metabolic remodeling and stress. In this review we discuss neuroprotective aspects of mitochondrial quality control proteases and neuropathological manifestations arising from defective proteolysis within the mitochondrion.
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Affiliation(s)
- Roman M Levytskyy
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Edward M Germany
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Oleh Khalimonchuk
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
- Nebraska Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
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34
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The m -AAA Protease Associated with Neurodegeneration Limits MCU Activity in Mitochondria. Mol Cell 2016; 64:148-162. [DOI: 10.1016/j.molcel.2016.08.020] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 06/16/2016] [Accepted: 08/12/2016] [Indexed: 11/23/2022]
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Stefely JA, Licitra F, Laredj L, Reidenbach AG, Kemmerer ZA, Grangeray A, Jaeg-Ehret T, Minogue CE, Ulbrich A, Hutchins PD, Wilkerson EM, Ruan Z, Aydin D, Hebert AS, Guo X, Freiberger EC, Reutenauer L, Jochem A, Chergova M, Johnson IE, Lohman DC, Rush MJP, Kwiecien NW, Singh PK, Schlagowski AI, Floyd BJ, Forsman U, Sindelar PJ, Westphall MS, Pierrel F, Zoll J, Dal Peraro M, Kannan N, Bingman CA, Coon JJ, Isope P, Puccio H, Pagliarini DJ. Cerebellar Ataxia and Coenzyme Q Deficiency through Loss of Unorthodox Kinase Activity. Mol Cell 2016; 63:608-620. [PMID: 27499294 DOI: 10.1016/j.molcel.2016.06.030] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 05/27/2016] [Accepted: 06/21/2016] [Indexed: 10/21/2022]
Abstract
The UbiB protein kinase-like (PKL) family is widespread, comprising one-quarter of microbial PKLs and five human homologs, yet its biochemical activities remain obscure. COQ8A (ADCK3) is a mammalian UbiB protein associated with ubiquinone (CoQ) biosynthesis and an ataxia (ARCA2) through unclear means. We show that mice lacking COQ8A develop a slowly progressive cerebellar ataxia linked to Purkinje cell dysfunction and mild exercise intolerance, recapitulating ARCA2. Interspecies biochemical analyses show that COQ8A and yeast Coq8p specifically stabilize a CoQ biosynthesis complex through unorthodox PKL functions. Although COQ8 was predicted to be a protein kinase, we demonstrate that it lacks canonical protein kinase activity in trans. Instead, COQ8 has ATPase activity and interacts with lipid CoQ intermediates, functions that are likely conserved across all domains of life. Collectively, our results lend insight into the molecular activities of the ancient UbiB family and elucidate the biochemical underpinnings of a human disease.
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Affiliation(s)
- Jonathan A Stefely
- Morgridge Institute for Research, Madison, WI 53715, USA; Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Floriana Licitra
- Département de Médecine Translationnelle et Neurogénétique, Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U596, CNRS UMR 7104, 67400 Illkirch, France; Université de Strasbourg, 67081 Strasbourg, France; Chaire de Génétique Humaine, Collège de France, 67404 Illkirch, France
| | - Leila Laredj
- Département de Médecine Translationnelle et Neurogénétique, Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U596, CNRS UMR 7104, 67400 Illkirch, France; Université de Strasbourg, 67081 Strasbourg, France; Chaire de Génétique Humaine, Collège de France, 67404 Illkirch, France
| | - Andrew G Reidenbach
- Morgridge Institute for Research, Madison, WI 53715, USA; Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Zachary A Kemmerer
- Morgridge Institute for Research, Madison, WI 53715, USA; Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Anais Grangeray
- Université de Strasbourg, 67081 Strasbourg, France; Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212, 67084 Strasbourg, France
| | - Tiphaine Jaeg-Ehret
- Département de Médecine Translationnelle et Neurogénétique, Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U596, CNRS UMR 7104, 67400 Illkirch, France; Université de Strasbourg, 67081 Strasbourg, France; Chaire de Génétique Humaine, Collège de France, 67404 Illkirch, France
| | - Catherine E Minogue
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Arne Ulbrich
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Paul D Hutchins
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Emily M Wilkerson
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Zheng Ruan
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA; Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Deniz Aydin
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland; Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Alexander S Hebert
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Xiao Guo
- Morgridge Institute for Research, Madison, WI 53715, USA; Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Elyse C Freiberger
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Laurence Reutenauer
- Département de Médecine Translationnelle et Neurogénétique, Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U596, CNRS UMR 7104, 67400 Illkirch, France; Université de Strasbourg, 67081 Strasbourg, France; Chaire de Génétique Humaine, Collège de France, 67404 Illkirch, France
| | - Adam Jochem
- Morgridge Institute for Research, Madison, WI 53715, USA
| | - Maya Chergova
- Département de Médecine Translationnelle et Neurogénétique, Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U596, CNRS UMR 7104, 67400 Illkirch, France; Université de Strasbourg, 67081 Strasbourg, France; Chaire de Génétique Humaine, Collège de France, 67404 Illkirch, France
| | - Isabel E Johnson
- Morgridge Institute for Research, Madison, WI 53715, USA; Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Danielle C Lohman
- Morgridge Institute for Research, Madison, WI 53715, USA; Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Matthew J P Rush
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Nicholas W Kwiecien
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Pankaj K Singh
- Département de Médecine Translationnelle et Neurogénétique, Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U596, CNRS UMR 7104, 67400 Illkirch, France; Université de Strasbourg, 67081 Strasbourg, France; Chaire de Génétique Humaine, Collège de France, 67404 Illkirch, France
| | - Anna I Schlagowski
- Fédération de Medicine Translationnelle de Strasbourg, EA3072, Faculté de Médicine et Faculté des Sciences du Sport, Université de Strasbourg, 67084 Strasbourg, France
| | - Brendan J Floyd
- Morgridge Institute for Research, Madison, WI 53715, USA; Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Ulrika Forsman
- University Grenoble Alpes, LCBM, UMR 5249, 38000 Grenoble, France
| | - Pavel J Sindelar
- University Grenoble Alpes, LCBM, UMR 5249, 38000 Grenoble, France; Laboratoire de Chimie des Processus Biologiques, CNRS UMR 8229, Collège de France, 75252 Paris, France
| | - Michael S Westphall
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Fabien Pierrel
- University Grenoble Alpes, LCBM, UMR 5249, 38000 Grenoble, France; TIMC-IMAG, CNRS UMR 5525, UFR de Médecine, University Joseph Fourier, 38706 La Tronche, France
| | - Joffrey Zoll
- Fédération de Medicine Translationnelle de Strasbourg, EA3072, Faculté de Médicine et Faculté des Sciences du Sport, Université de Strasbourg, 67084 Strasbourg, France
| | - Matteo Dal Peraro
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland; Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Natarajan Kannan
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA; Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Craig A Bingman
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Joshua J Coon
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA; Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Philippe Isope
- Université de Strasbourg, 67081 Strasbourg, France; Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212, 67084 Strasbourg, France
| | - Hélène Puccio
- Département de Médecine Translationnelle et Neurogénétique, Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U596, CNRS UMR 7104, 67400 Illkirch, France; Université de Strasbourg, 67081 Strasbourg, France; Chaire de Génétique Humaine, Collège de France, 67404 Illkirch, France.
| | - David J Pagliarini
- Morgridge Institute for Research, Madison, WI 53715, USA; Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
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Mark MD, Schwitalla JC, Groemmke M, Herlitze S. Keeping Our Calcium in Balance to Maintain Our Balance. Biochem Biophys Res Commun 2016; 483:1040-1050. [PMID: 27392710 DOI: 10.1016/j.bbrc.2016.07.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 07/04/2016] [Indexed: 01/13/2023]
Abstract
Calcium is a key signaling molecule and ion involved in a variety of diverse processes in our central nervous system (CNS) which include gene expression, synaptic transmission and plasticity, neuronal excitability and cell maintenance. Proper control of calcium signaling is not only vital for neuronal physiology but also cell survival. Mutations in fundamental channels, transporters and second messenger proteins involved in orchestrating the balance of our calcium homeostasis can lead to severe neurodegenerative disorders, such as Spinocerebellar (SCA) and Episodic (EA) ataxias. Hereditary ataxias make up a remarkably diverse group of neurological disorders clinically characterized by gait ataxia, nystagmus, dysarthria, trunk and limb ataxia and often atrophy of the cerebellum. The largest family of hereditary ataxias is SCAs which consists of a growing family of 42 members. A relatively smaller family of 8 members compose the EAs. The gene mutations responsible for half of the EA members and over 35 of the SCA subtypes have been identified, and several have been found to be responsible for cerebellar atrophy, abnormal intracellular calcium levels, dysregulation of Purkinje cell pacemaking, altered cerebellar synaptic transmission and/or ataxia in mouse models. Although the genetic diversity and affected cellular pathways of hereditary ataxias are broad, one common theme amongst these genes is their effects on maintaining calcium balance in primarily the cerebellum. There is emerging evidence that the pathogenesis of hereditary ataxias may be caused by imbalances in intracellular calcium due to genetic mutations in calcium-mediating proteins. In this review we will discuss the current evidence supporting the role of deranged calcium as the culprit to neurodegenerative diseases with a primary focus on SCAs and EAs.
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Affiliation(s)
- Melanie D Mark
- Department of Zoology and Neurobiology, ND7/31, Ruhr University Bochum, Universitätsstr. 150, D-44780 Bochum, Germany.
| | - Jan Claudius Schwitalla
- Department of Zoology and Neurobiology, ND7/31, Ruhr University Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| | - Michelle Groemmke
- Department of Zoology and Neurobiology, ND7/31, Ruhr University Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| | - Stefan Herlitze
- Department of Zoology and Neurobiology, ND7/31, Ruhr University Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
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Perkins E, Suminaite D, Jackson M. Cerebellar ataxias: β-III spectrin's interactions suggest common pathogenic pathways. J Physiol 2016; 594:4661-76. [PMID: 26821241 PMCID: PMC4983618 DOI: 10.1113/jp271195] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 12/14/2015] [Indexed: 12/12/2022] Open
Abstract
Spinocerebellar ataxias (SCAs) are a genetically heterogeneous group of disorders all characterised by postural abnormalities, motor deficits and cerebellar degeneration. Animal and in vitro models have revealed β‐III spectrin, a cytoskeletal protein present throughout the soma and dendritic tree of cerebellar Purkinje cells, to be required for the maintenance of dendritic architecture and for the trafficking and/or stabilisation of several membrane proteins: ankyrin‐R, cell adhesion molecules, metabotropic glutamate receptor‐1 (mGluR1), voltage‐gated sodium channels (Nav) and glutamate transporters. This scaffold of interactions connects β‐III spectrin to a wide variety of proteins implicated in the pathology of many SCAs. Heterozygous mutations in the gene encoding β‐III spectrin (SPTBN2) underlie SCA type‐5 whereas homozygous mutations cause spectrin associated autosomal recessive ataxia type‐1 (SPARCA1), an infantile form of ataxia with cognitive impairment. Loss‐of β‐III spectrin function appears to underpin cerebellar dysfunction and degeneration in both diseases resulting in thinner dendrites, excessive dendritic protrusion with loss of planarity, reduced resurgent sodium currents and abnormal glutamatergic neurotransmission. The initial physiological consequences are a decrease in spontaneous activity and excessive excitation, likely to be offsetting each other, but eventually hyperexcitability gives rise to dark cell degeneration and reduced cerebellar output. Similar molecular mechanisms have been implicated for SCA1, 2, 3, 7, 13, 14, 19, 22, 27 and 28, highlighting alterations to intrinsic Purkinje cell activity, dendritic architecture and glutamatergic transmission as possible common mechanisms downstream of various loss‐of‐function primary genetic defects. A key question for future research is whether similar mechanisms underlie progressive cerebellar decline in normal ageing.
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Affiliation(s)
- Emma Perkins
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Daumante Suminaite
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Mandy Jackson
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
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Yang Y, Liu W, Fang Z, Shi J, Che F, He C, Yao L, Wang E, Wu Y. A Newly Identified Missense Mutation in FARS2 Causes Autosomal-Recessive Spastic Paraplegia. Hum Mutat 2015; 37:165-9. [PMID: 26553276 DOI: 10.1002/humu.22930] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 11/03/2015] [Indexed: 02/05/2023]
Abstract
Hereditary spastic paraplegia (HSP) is a clinically and genetically heterogeneous group of neurodegenerative disorders characterized by spasticity of the lower limbs due to pyramidal tract dysfunction. Here, we report that a missense homozygous mutation c.424G>T (p.D142Y) in the FARS2 gene, which encodes a mitochondrial phenylalanyl tRNA synthetase (mtPheRS), causes HSP in a Chinese consanguineous family by using combination of homozygous mapping and whole-exome sequencing. Immunohistochemical experiments were performed showing that the FARS2 protein was highly expressed in the Purkinje cells of rat cerebellum. The aminoacylation activity of mtPheRS was severely disrupted by the p.D142Y substitution in vitro not only in the first aminoacylation step but also in the last transfer step. Taken together, our results indicate that a missense mutation in FARS2 contributes to HSP, which has the clinical significance of the regulation of tRNA synthetases in human neurodegenerative diseases.
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Affiliation(s)
- Ying Yang
- Department of Biochemistry and Molecular Biology, Xi'an, Shaanxi, 710032, China.,Center for DNA Typing, Xi'an, Shaanxi, 710032, China
| | - Wei Liu
- Department of physiotherapy, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, 710032, China
| | - Zhipeng Fang
- Center for RNA Research, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Shanghai, 710031, China
| | - Juan Shi
- Department of Anatomy, Histology and Embryology & K.K. Leung Brain Research Centre, Preclinical School of Medicine, Fourth Military Medical University, Xi'an, Shaanxi, 200032, China
| | - Fengyu Che
- Center for DNA Typing, Xi'an, Shaanxi, 710032, China
| | - Chunxia He
- Department of Biochemistry and Molecular Biology, Xi'an, Shaanxi, 710032, China.,Center for DNA Typing, Xi'an, Shaanxi, 710032, China
| | - Libo Yao
- Department of Biochemistry and Molecular Biology, Xi'an, Shaanxi, 710032, China
| | - Enduo Wang
- Center for RNA Research, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Shanghai, 710031, China
| | - Yuanming Wu
- Department of Biochemistry and Molecular Biology, Xi'an, Shaanxi, 710032, China.,Center for DNA Typing, Xi'an, Shaanxi, 710032, China
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39
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Abstract
Mitochondria are mobile organelles that dynamically remodel their membranes and actively migrate along cytoskeletal tracks. There is overwhelming evidence that regulators of mitochondrial dynamics are critical for the survival and function of neural tissues. In multiple animal models, ablation of genes regulating mitochondrial shape result in stunted neural development and neurodegeneration. Organotypic cultures serve as ideal in vitro tissue models to further dissect the mechanisms of mitochondrial function in neuronal survival. Slice cultures preserve the three-dimensional cytoarchitecture of neural networks and can survive for prolonged periods in culture. In addition, these cultures allow long-term assessment of genetic or pharmacologic perturbations on neuronal function. Organotypic preparations from murine and rat models have been developed for many regions of the brain. In this chapter, we describe our methods for preparing basal ganglia and cerebellar slice cultures suitable for studying mitochondrial function in Parkinson's disease and cerebellar ataxia, respectively. With such slices, we describe a robust method for live imaging of mitochondrial dynamics. To quantitatively analyze mitochondrial motility, we show how to generate kymographs using the open source image analysis program ImageJ. These techniques provide a powerful platform for assessing mitochondrial activity in neural networks.
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Affiliation(s)
- Anh H Pham
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - David C Chan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA; Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California, USA.
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40
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De Silva D, Tu YT, Amunts A, Fontanesi F, Barrientos A. Mitochondrial ribosome assembly in health and disease. Cell Cycle 2015; 14:2226-50. [PMID: 26030272 DOI: 10.1080/15384101.2015.1053672] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The ribosome is a structurally and functionally conserved macromolecular machine universally responsible for catalyzing protein synthesis. Within eukaryotic cells, mitochondria contain their own ribosomes (mitoribosomes), which synthesize a handful of proteins, all essential for the biogenesis of the oxidative phosphorylation system. High-resolution cryo-EM structures of the yeast, porcine and human mitoribosomal subunits and of the entire human mitoribosome have uncovered a wealth of new information to illustrate their evolutionary divergence from their bacterial ancestors and their adaptation to synthesis of highly hydrophobic membrane proteins. With such structural data becoming available, one of the most important remaining questions is that of the mitoribosome assembly pathway and factors involved. The regulation of mitoribosome biogenesis is paramount to mitochondrial respiration, and thus to cell viability, growth and differentiation. Moreover, mutations affecting the rRNA and protein components produce severe human mitochondrial disorders. Despite its biological and biomedical significance, knowledge on mitoribosome biogenesis and its deviations from the much-studied bacterial ribosome assembly processes is scarce, especially the order of rRNA processing and assembly events and the regulatory factors required to achieve fully functional particles. This article focuses on summarizing the current available information on mitoribosome assembly pathway, factors that form the mitoribosome assembly machinery, and the effect of defective mitoribosome assembly on human health.
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Affiliation(s)
- Dasmanthie De Silva
- a Department of Biochemistry and Molecular Biology ; University of Miami Miller School of Medicine ; Miami , FL USA
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41
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Abstract
Recent advances in mitochondrial biology have revealed the high diversity and complexity of proteolytic enzymes that regulate mitochondrial function. We have classified mitochondrial proteases, or mitoproteases, on the basis of their function and location, and defined the human mitochondrial degradome as the complete set of mitoproteases that are encoded by the human genome. In addition to their nonspecific degradative functions, mitoproteases perform highly regulated proteolytic reactions that are important in mitochondrial function, integrity and homeostasis. These include protein synthesis, quality control, mitochondrial biogenesis and dynamics, mitophagy and apoptosis. Impaired or dysregulated function of mitoproteases is associated with ageing and with many pathological conditions such as neurodegenerative disorders, metabolic syndromes and cancer. A better understanding of the mitochondrial proteolytic landscape and its modulation may contribute to improving human lifespan and 'healthspan'.
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42
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Iommarini L, Peralta S, Torraco A, Diaz F. Mitochondrial Diseases Part II: Mouse models of OXPHOS deficiencies caused by defects in regulatory factors and other components required for mitochondrial function. Mitochondrion 2015; 22:96-118. [PMID: 25640959 DOI: 10.1016/j.mito.2015.01.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 01/22/2015] [Indexed: 01/21/2023]
Abstract
Mitochondrial disorders are defined as defects that affect the oxidative phosphorylation system (OXPHOS). They are characterized by a heterogeneous array of clinical presentations due in part to a wide variety of factors required for proper function of the components of the OXPHOS system. There is no cure for these disorders owing to our poor knowledge of the pathogenic mechanisms of disease. To understand the mechanisms of human disease numerous mouse models have been developed in recent years. Here we summarize the features of several mouse models of mitochondrial diseases directly related to those factors affecting mtDNA maintenance, replication, transcription, translation as well as other proteins that are involved in mitochondrial dynamics and quality control which affect mitochondrial OXPHOS function without being intrinsic components of the system. We discuss how these models have contributed to our understanding of mitochondrial diseases and their pathogenic mechanisms.
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Affiliation(s)
- Luisa Iommarini
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Via Irnerio 42, 40128 Bologna, Italy.
| | - Susana Peralta
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
| | - Alessandra Torraco
- Unit for Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Viale di San Paolo, 15 - 00146, Rome, Italy.
| | - Francisca Diaz
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
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Maltecca F, Baseggio E, Consolato F, Mazza D, Podini P, Young SM, Drago I, Bahr BA, Puliti A, Codazzi F, Quattrini A, Casari G. Purkinje neuron Ca2+ influx reduction rescues ataxia in SCA28 model. J Clin Invest 2014; 125:263-74. [PMID: 25485680 DOI: 10.1172/jci74770] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 11/06/2014] [Indexed: 12/11/2022] Open
Abstract
Spinocerebellar ataxia type 28 (SCA28) is a neurodegenerative disease caused by mutations of the mitochondrial protease AFG3L2. The SCA28 mouse model, which is haploinsufficient for Afg3l2, exhibits a progressive decline in motor function and displays dark degeneration of Purkinje cells (PC-DCD) of mitochondrial origin. Here, we determined that mitochondria in cultured Afg3l2-deficient PCs ineffectively buffer evoked Ca²⁺ peaks, resulting in enhanced cytoplasmic Ca²⁺ concentrations, which subsequently triggers PC-DCD. This Ca²⁺-handling defect is the result of negative synergism between mitochondrial depolarization and altered organelle trafficking to PC dendrites in Afg3l2-mutant cells. In SCA28 mice, partial genetic silencing of the metabotropic glutamate receptor mGluR1 decreased Ca²⁺ influx in PCs and reversed the ataxic phenotype. Moreover, administration of the β-lactam antibiotic ceftriaxone, which promotes synaptic glutamate clearance, thereby reducing Ca²⁺ influx, improved ataxia-associated phenotypes in SCA28 mice when given either prior to or after symptom onset. Together, the results of this study indicate that ineffective mitochondrial Ca²⁺ handling in PCs underlies SCA28 pathogenesis and suggest that strategies that lower glutamate stimulation of PCs should be further explored as a potential treatment for SCA28 patients.
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Wang X, Li H, Zheng A, Yang L, Liu J, Chen C, Tang Y, Zou X, Li Y, Long J, Liu J, Zhang Y, Feng Z. Mitochondrial dysfunction-associated OPA1 cleavage contributes to muscle degeneration: preventative effect of hydroxytyrosol acetate. Cell Death Dis 2014; 5:e1521. [PMID: 25393477 PMCID: PMC4260731 DOI: 10.1038/cddis.2014.473] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 08/27/2014] [Accepted: 10/06/2014] [Indexed: 01/15/2023]
Abstract
Mitochondrial dysfunction contributes to the development of muscle disorders, including muscle wasting, muscle atrophy and degeneration. Despite the knowledge that oxidative stress closely interacts with mitochondrial dysfunction, the detailed mechanisms remain obscure. In this study, tert-butylhydroperoxide (t-BHP) was used to induce oxidative stress on differentiated C2C12 myotubes. t-BHP induced significant mitochondrial dysfunction in a time-dependent manner, accompanied by decreased myosin heavy chain (MyHC) expression at both the mRNA and protein levels. Consistently, endogenous reactive oxygen species (ROS) overproduction triggered by carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP), a mitochondrial oxidative phosphorylation inhibitor, was accompanied by decreased membrane potential and decreased MyHC protein content. However, the free radical scavenger N-acetyl-L-cysteine (NAC) efficiently reduced the ROS level and restored MyHC content, suggesting a close association between ROS and MyHC expression. Meanwhile, we found that both t-BHP and FCCP promoted the cleavage of optic atrophy 1 (OPA1) from the long form into short form during the early stages. In addition, the ATPase family gene 3-like 2, a mitochondrial inner membrane protease, was also markedly increased. Moreover, OPA1 knockdown in myotubes was accompanied by decreased MyHC content, whereas NAC failed to prevent FCCP-induced MyHC decrease with OPA1 knockdown, suggesting that ROS might affect MyHC content by modulating OPA1 cleavage. In addition, hydroxytyrosol acetate (HT-AC), an important compound in virgin olive oil, could significantly prevent t-BHP-induced mitochondrial membrane potential and cell viability loss in myotubes. Specifically, HT-AC inhibited t-BHP-induced OPA1 cleavage and mitochondrial morphology changes, accompanied by improvement on mitochondrial oxygen consumption capacity, ATP productive potential and activities of mitochondrial complex I, II and V. Moreover, both t-BHP- and FCCP-induced MyHC decrease was sufficiently inhibited by HT-AC. Taken together, our data provide evidence indicating that mitochondrial dysfunction-associated OPA1 cleavage may contribute to muscle degeneration, and olive oil compounds could be effective nutrients for preventing the development of muscle disorders.
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Affiliation(s)
- X Wang
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - H Li
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - A Zheng
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - L Yang
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - J Liu
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - C Chen
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Y Tang
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - X Zou
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Y Li
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - J Long
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - J Liu
- 1] Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China [2] Tianjin Key Laboratory of Exercise Physiology & Sports Medicine, Tianjin University of Sport, Tianjin 300381, China
| | - Y Zhang
- Tianjin Key Laboratory of Exercise Physiology & Sports Medicine, Tianjin University of Sport, Tianjin 300381, China
| | - Z Feng
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
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45
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Myers KA, Warman Chardon J, Huang L, Boycott KM. Deletion ofAFG3L2associated with spinocerebellar ataxia type 28 in the context of multiple genomic anomalies. Am J Med Genet A 2014; 164A:3209-12. [DOI: 10.1002/ajmg.a.36771] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Accepted: 08/20/2014] [Indexed: 11/10/2022]
Affiliation(s)
- Kenneth A. Myers
- Division of Neurology; Department of Pediatrics; Alberta Children's Hospital; University of Calgary; Calgary Alberta Canada
| | - Jodi Warman Chardon
- Department of Genetics; Children's Hospital of Eastern Ontario; University of Ottawa; Ottawa Ontario Canada
| | - Lijia Huang
- Department of Genetics; Children's Hospital of Eastern Ontario; University of Ottawa; Ottawa Ontario Canada
| | - Kym M. Boycott
- Department of Genetics; Children's Hospital of Eastern Ontario; University of Ottawa; Ottawa Ontario Canada
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46
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Matilla-Dueñas A, Ashizawa T, Brice A, Magri S, McFarland KN, Pandolfo M, Pulst SM, Riess O, Rubinsztein DC, Schmidt J, Schmidt T, Scoles DR, Stevanin G, Taroni F, Underwood BR, Sánchez I. Consensus paper: pathological mechanisms underlying neurodegeneration in spinocerebellar ataxias. THE CEREBELLUM 2014; 13:269-302. [PMID: 24307138 DOI: 10.1007/s12311-013-0539-y] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Intensive scientific research devoted in the recent years to understand the molecular mechanisms or neurodegeneration in spinocerebellar ataxias (SCAs) are identifying new pathways and targets providing new insights and a better understanding of the molecular pathogenesis in these diseases. In this consensus manuscript, the authors discuss their current views on the identified molecular processes causing or modulating the neurodegenerative phenotype in spinocerebellar ataxias with the common opinion of translating the new knowledge acquired into candidate targets for therapy. The following topics are discussed: transcription dysregulation, protein aggregation, autophagy, ion channels, the role of mitochondria, RNA toxicity, modulators of neurodegeneration and current therapeutic approaches. Overall point of consensus includes the common vision of neurodegeneration in SCAs as a multifactorial, progressive and reversible process, at least in early stages. Specific points of consensus include the role of the dysregulation of protein folding, transcription, bioenergetics, calcium handling and eventual cell death with apoptotic features of neurons during SCA disease progression. Unresolved questions include how the dysregulation of these pathways triggers the onset of symptoms and mediates disease progression since this understanding may allow effective treatments of SCAs within the window of reversibility to prevent early neuronal damage. Common opinions also include the need for clinical detection of early neuronal dysfunction, for more basic research to decipher the early neurodegenerative process in SCAs in order to give rise to new concepts for treatment strategies and for the translation of the results to preclinical studies and, thereafter, in clinical practice.
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Affiliation(s)
- A Matilla-Dueñas
- Health Sciences Research Institute Germans Trias i Pujol (IGTP), Ctra. de Can Ruti, Camí de les Escoles s/n, Badalona, Barcelona, Spain,
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47
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Guan X, Duan Y, Zeng Q, Pan H, Qian Y, Li D, Cao X, Liu M. Lgr4 protein deficiency induces ataxia-like phenotype in mice and impairs long term depression at cerebellar parallel fiber-Purkinje cell synapses. J Biol Chem 2014; 289:26492-26504. [PMID: 25063812 DOI: 10.1074/jbc.m114.564138] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cerebellar dysfunction causes ataxia characterized by loss of balance and coordination. Until now, the molecular and neuronal mechanisms of several types of inherited cerebellar ataxia have not been completely clarified. Here, we report that leucine-rich G protein-coupled receptor 4 (Lgr4/Gpr48) is highly expressed in Purkinje cells (PCs) in the cerebellum. Deficiency of Lgr4 leads to an ataxia-like phenotype in mice. Histologically, no obvious morphological changes were observed in the cerebellum of Lgr4 mutant mice. However, the number of PCs was slightly but significantly reduced in Lgr4(-/-) mice. In addition, in vitro electrophysiological analysis showed an impaired long term depression (LTD) at parallel fiber-PC (PF-PC) synapses in Lgr4(-/-) mice. Consistently, immunostaining experiments showed that the level of phosphorylated cAMP-responsive element-binding protein (Creb) was significantly decreased in Lgr4(-/-) PCs. Furthermore, treatment with forskolin, an adenylyl cyclase agonist, rescued phospho-Creb in PCs and reversed the impairment in PF-PC LTD in Lgr4(-/-) cerebellar slices, indicating that Lgr4 is an upstream regulator of Creb signaling, which is underlying PF-PC LTD. Together, our findings demonstrate for first time an important role for Lgr4 in motor coordination and cerebellar synaptic plasticity and provide a potential therapeutic target for certain types of inherited cerebellar ataxia.
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Affiliation(s)
- Xin Guan
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, and East China Normal University, Shanghai 200241, China
| | - Yanhong Duan
- Key Laboratory of Brain Functional Genomics, Ministry of Education, East China Normal University, Shanghai 200241, China, and
| | - Qingwen Zeng
- Key Laboratory of Brain Functional Genomics, Ministry of Education, East China Normal University, Shanghai 200241, China, and
| | - Hongjie Pan
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, and East China Normal University, Shanghai 200241, China
| | - Yu Qian
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, and East China Normal University, Shanghai 200241, China
| | - Dali Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, and East China Normal University, Shanghai 200241, China.
| | - Xiaohua Cao
- Key Laboratory of Brain Functional Genomics, Ministry of Education, East China Normal University, Shanghai 200241, China, and.
| | - Mingyao Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, and East China Normal University, Shanghai 200241, China; Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas 77030.
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48
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Lo Giudice T, Lombardi F, Santorelli FM, Kawarai T, Orlacchio A. Hereditary spastic paraplegia: clinical-genetic characteristics and evolving molecular mechanisms. Exp Neurol 2014; 261:518-39. [PMID: 24954637 DOI: 10.1016/j.expneurol.2014.06.011] [Citation(s) in RCA: 237] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Revised: 06/07/2014] [Accepted: 06/12/2014] [Indexed: 12/12/2022]
Abstract
Hereditary spastic paraplegia (HSP) is a group of clinically and genetically heterogeneous neurological disorders characterized by pathophysiologic hallmark of length-dependent distal axonal degeneration of the corticospinal tracts. The prominent features of this pathological condition are progressive spasticity and weakness of the lower limbs. To date, 72 spastic gait disease-loci and 55 spastic paraplegia genes (SPGs) have been identified. All modes of inheritance (autosomal dominant, autosomal recessive, and X-linked) have been described. Recently, a late onset spastic gait disorder with maternal trait of inheritance has been reported, as well as mutations in genes not yet classified as spastic gait disease. Several cellular processes are involved in its pathogenesis, such as membrane and axonal transport, endoplasmic reticulum membrane modeling and shaping, mitochondrial function, DNA repair, autophagy, and abnormalities in lipid metabolism and myelination processes. Moreover, recent evidences have been found about the impairment of endosome membrane trafficking in vesicle formation and about the involvement of oxidative stress and mtDNA polymorphisms in the onset of the disease. Interactome networks have been postulated by bioinformatics and biological analyses of spastic paraplegia genes, which would contribute to the development of new therapeutic approaches.
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Affiliation(s)
- Temistocle Lo Giudice
- Laboratorio di Neurogenetica, Centro Europeo di Ricerca sul Cervello (CERC) - Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Santa Lucia, Rome, Italy; Dipartimento di Medicina dei Sistemi, Università di Roma "Tor Vergata", Rome, Italy
| | - Federica Lombardi
- Laboratorio di Neurogenetica, Centro Europeo di Ricerca sul Cervello (CERC) - Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Santa Lucia, Rome, Italy
| | - Filippo Maria Santorelli
- Unità Operativa Complessa di Medicina Molecolare, Neurogenetica e Malattie Neurodegenerative, IRCCS Stella Maris, Pisa, Italy
| | - Toshitaka Kawarai
- Department of Clinical Neuroscience, Institute of Health Biosciences, Graduate School of Medicine, University of Tokushima, Tokushima, Japan
| | - Antonio Orlacchio
- Laboratorio di Neurogenetica, Centro Europeo di Ricerca sul Cervello (CERC) - Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Santa Lucia, Rome, Italy; Dipartimento di Medicina dei Sistemi, Università di Roma "Tor Vergata", Rome, Italy.
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49
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Pagano G, Shyamsunder P, Verma RS, Lyakhovich A. Damaged mitochondria in Fanconi anemia - an isolated event or a general phenomenon? Oncoscience 2014; 1:287-95. [PMID: 25594021 PMCID: PMC4278298 DOI: 10.18632/oncoscience.29] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 04/20/2014] [Indexed: 12/21/2022] Open
Abstract
Fanconi anemia (FA) is known as an inherited bone marrow failure syndrome associated with cancer predisposition and susceptibility to a number of DNA damaging stimuli, along with a number of clinical features such as upper limb malformations, increased diabetes incidence and typical anomalies in skin pigmentation. The proteins encoded by FA-defective genes (FANC proteins) display well-established roles in DNA damage and repair pathways. Moreover, some independent studies have revealed that mitochondrial dysfunction (MDF) is also involved in FA phenotype. Unconfined to FA, we have shown that other syndromes featuring DNA damage and repair (such as ataxia-telangiectasia, AT, and Werner syndrome, WS) display MDF-related phenotypes, along with oxidative stress (OS) that, altogether, may play major roles in these diseases. Experimental and clinical studies are warranted in the prospect of future therapies to be focused on compounds scavenging reactive oxygen species (ROS) as well as protecting mitochondrial functions.
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Affiliation(s)
- Giovanni Pagano
- Italian National Cancer Institute, G Pascale Foundation, CROM, Mercogliano, AV, Italy
| | - Pavithra Shyamsunder
- Stem Cell and Molecular Biology laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai
| | - Rama S Verma
- Stem Cell and Molecular Biology laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai
| | - Alex Lyakhovich
- Duke-NUS Graduate Medical School, Singapore ; Novosibirsk Institute of Molecular Biology and Biophysics, Russian Federation ; Queen's University Belfast, UK
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50
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Smeets CJLM, Verbeek DS. Cerebellar ataxia and functional genomics: Identifying the routes to cerebellar neurodegeneration. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2030-2038. [PMID: 24726947 DOI: 10.1016/j.bbadis.2014.04.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 03/25/2014] [Accepted: 04/02/2014] [Indexed: 12/20/2022]
Abstract
Cerebellar ataxias are progressive neurodegenerative disorders characterized by atrophy of the cerebellum leading to motor dysfunction, balance problems, and limb and gait ataxia. These include among others, the dominantly inherited spinocerebellar ataxias, recessive cerebellar ataxias such as Friedreich's ataxia, and X-linked cerebellar ataxias. Since all cerebellar ataxias display considerable overlap in their disease phenotypes, common pathological pathways must underlie the selective cerebellar neurodegeneration. Therefore, it is important to identify the molecular mechanisms and routes to neurodegeneration that cause cerebellar ataxia. In this review, we discuss the use of functional genomic approaches including whole-exome sequencing, genome-wide gene expression profiling, miRNA profiling, epigenetic profiling, and genetic modifier screens to reveal the underlying pathogenesis of various cerebellar ataxias. These approaches have resulted in the identification of many disease genes, modifier genes, and biomarkers correlating with specific stages of the disease. This article is part of a Special Issue entitled: From Genome to Function.
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Affiliation(s)
- C J L M Smeets
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - D S Verbeek
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
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