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Lebon C, Behar-Cohen F, Torriglia A. Cell Death Mechanisms in a Mouse Model of Retinal Degeneration in Spinocerebellar Ataxia 7. Neuroscience 2019; 400:72-84. [PMID: 30625334 DOI: 10.1016/j.neuroscience.2018.12.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 12/30/2018] [Accepted: 12/31/2018] [Indexed: 10/27/2022]
Abstract
Spino-cerebellar ataxia type 7 (SCA7) is a polyglutamine (polyQ) disorder characterized by neurodegeneration of the brain, cerebellum, and retina caused by a polyglutamine expansion in ataxin7. The presence of an expanded polyQ tract in a mutant protein is known to induce protein aggregation, cellular stress, toxicity, and finally cell death. However, the consequences of the presence of mutant ataxin7 in the retina and the mechanisms underlying photoreceptor degeneration remain poorly understood. In this study, we show that in a retinal SCA7 mouse model, polyQ ataxin7 induces stress within the retina and activates Muller cells. Moreover, unfolded protein response and autophagy are activated in SCA7 photoreceptors. We have also shown that the photoreceptor death does not involve a caspase-dependent apoptosis but instead involves apoptosis inducing factor (AIF) and Leukocyte Elastase Inhibitor (LEI/L-DNase II). When these two cell death effectors are downregulated by their siRNA, a significant reduction in photoreceptor death is observed. These results highlight the consequences of polyQ protein expression in the retina and the role of caspase-independent pathways involved in photoreceptor cell death.
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Affiliation(s)
- Cecile Lebon
- Inserm U1138. Centre des Recherches des Cordeliers, 15, rue de l'Ecole de Médecine, 78006 Paris, France; Université Pierre et Marie Curie, France; Université Paris Descartes, France
| | - Francine Behar-Cohen
- Inserm U1138. Centre des Recherches des Cordeliers, 15, rue de l'Ecole de Médecine, 78006 Paris, France; Université Pierre et Marie Curie, France; Université Paris Descartes, France
| | - Alicia Torriglia
- Inserm U1138. Centre des Recherches des Cordeliers, 15, rue de l'Ecole de Médecine, 78006 Paris, France; Université Pierre et Marie Curie, France; Université Paris Descartes, France.
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Ramos A, Planchat M, Vieira Melo AR, Raposo M, Shamim U, Suroliya V, Srivastava AK, Faruq M, Morino H, Ohsawa R, Kawakami H, Bannach Jardim L, Saraiva-Pereira ML, Vasconcelos J, Santos C, Lima M. Mitochondrial DNA haplogroups and age at onset of Machado-Joseph disease/spinocerebellar ataxia type 3: a study in patients from multiple populations. Eur J Neurol 2018; 26:506-512. [PMID: 30414314 DOI: 10.1111/ene.13860] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 11/06/2018] [Indexed: 01/16/2023]
Abstract
BACKGROUND AND PURPOSE Mitochondrial dysfunction has been implicated in the pathogenesis of several neurodegenerative disorders, including Machado-Joseph disease (MJD), an autosomal dominant late-onset polyglutamine ataxia that results from an unstable expansion of a CAG tract in the ATXN3 gene. The size of the CAG tract only partially explains age at onset (AO), highlighting the existence of disease modifiers. Mitochondrial DNA (mtDNA) haplogroups have been associated with clinical presentation in other polyglutamine disorders, constituting potential modifiers of MJD phenotype. METHODS A cross-sectional study, using 235 unrelated patients from Portugal, Brazil, India and Japan, was performed to investigate if mtDNA haplogroups contribute to AO of MJD. mtDNA haplogroups were obtained after sequencing the mtDNA hypervariable region I. Patients were classified in 15 phylogenetically related haplogroup clusters. RESULTS The AO was significantly different among populations, implying the existence of other non-CAG factors, which seem to be population specific. In the Portuguese population, patients classified as belonging to haplogroup JT presented the earliest onset (estimated onset 34.6 years of age). Haplogroups W and X seem to have a protective effect, causing a delay in onset (estimated onset 47 years of age). No significant association between haplogroup clusters and AO was detected in the other populations or when all patients were pooled. Although haplogroup JT has already been implicated in other neurodegenerative disorders, no previous reports of an association between haplogroups W and X and disease were found. CONCLUSIONS These findings suggest that haplogroups JT, W and X modify AO in MJD. Replication studies should be performed in European populations, where the frequency of the candidate modifiers is similar.
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Affiliation(s)
- A Ramos
- Faculdade de Ciências e Tecnologia, Universidade dos Açores, Ponta Delgada, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,Departamento Biologia Animal, Biologia Vegetal i Ecologia, Unitat d'Antropologia Biològica, Universitat Autònoma de Barcelona, Cerdanyola del Valles, Spain
| | - M Planchat
- Departamento Biologia Animal, Biologia Vegetal i Ecologia, Unitat d'Antropologia Biològica, Universitat Autònoma de Barcelona, Cerdanyola del Valles, Spain
| | - A R Vieira Melo
- Faculdade de Ciências e Tecnologia, Universidade dos Açores, Ponta Delgada, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - M Raposo
- Faculdade de Ciências e Tecnologia, Universidade dos Açores, Ponta Delgada, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - U Shamim
- CSIR - Institute of Genomics and Integrative Biology (IGIB), New Delhi, India
| | - V Suroliya
- CSIR - Institute of Genomics and Integrative Biology (IGIB), New Delhi, India.,Department of Neurology, Neuroscience Centre, All India Institute of Medical Sciences, New Delhi, India
| | - A K Srivastava
- Department of Neurology, Neuroscience Centre, All India Institute of Medical Sciences, New Delhi, India
| | - M Faruq
- CSIR - Institute of Genomics and Integrative Biology (IGIB), New Delhi, India
| | - H Morino
- Department of Epidemiology, Research Institute for Radiology and Medicine, Hiroshima University, Hiroshima, Japan
| | - R Ohsawa
- Department of Epidemiology, Research Institute for Radiology and Medicine, Hiroshima University, Hiroshima, Japan
| | - H Kawakami
- Department of Epidemiology, Research Institute for Radiology and Medicine, Hiroshima University, Hiroshima, Japan
| | - L Bannach Jardim
- Medical Genetics Service, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil.,Departamento de Medicina Interna, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - M L Saraiva-Pereira
- Medical Genetics Service, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil.,Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - J Vasconcelos
- Serviço de Neurologia, Hospital do Divino Espírito Santo, Ponta Delgada, Açores, Portugal
| | - C Santos
- Departamento Biologia Animal, Biologia Vegetal i Ecologia, Unitat d'Antropologia Biològica, Universitat Autònoma de Barcelona, Cerdanyola del Valles, Spain
| | - M Lima
- Faculdade de Ciências e Tecnologia, Universidade dos Açores, Ponta Delgada, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
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Sinha S, Goyal S, Somvanshi P, Grover A. Mechanistic Insights into the Binding of Class IIa HDAC Inhibitors toward Spinocerebellar Ataxia Type-2: A 3D-QSAR and Pharmacophore Modeling Approach. Front Neurosci 2017; 10:606. [PMID: 28119557 PMCID: PMC5223442 DOI: 10.3389/fnins.2016.00606] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 12/20/2016] [Indexed: 12/18/2022] Open
Abstract
Spinocerebellar ataxia (SCA-2) type-2 is a rare neurological disorder among the nine polyglutamine disorders, mainly caused by polyQ (CAG) trinucleotide repeats expansion within gene coding ataxin-2 protein. The expanded trinucleotide repeats within the ataxin-2 protein sequesters transcriptional cofactors i.e., CREB-binding protein (CBP), Ataxin-2 binding protein 1 (A2BP1) leading to a state of hypo-acetylation and transcriptional repression. Histone de-acetylases inhibitors (HDACi) have been reported to restore transcriptional balance through inhibition of class IIa HDAC's, that leads to an increased acetylation and transcription as demonstrated through in-vivo studies on mouse models of Huntington's. In this study, 61 di-aryl cyclo-propanehydroxamic acid derivatives were used for developing three dimensional (3D) QSAR and pharmacophore models. These models were then employed for screening and selection of anti-ataxia compounds. The chosen QSAR model was observed to be statistically robust with correlation coefficient (r2) value of 0.6774, cross-validated correlation coefficient (q2) of 0.6157 and co-relation coefficient for external test set (pred_r2) of 0.7570. A high F-test value of 77.7093 signified the robustness of the model. Two potential drug leads ZINC 00608101 (SEI) and ZINC 00329110 (ACI) were selected after a coalesce procedure of pharmacophore based screening using the pharmacophore model ADDRR.20 and structural analysis using molecular docking and dynamics simulations. The pharmacophore and the 3D-QSAR model generated were further validated for their screening and prediction ability using the enrichment factor (EF), goodness of hit (GH), and receiver operating characteristics (ROC) curve analysis. The compounds SEI and ACI exhibited a docking score of −10.097 and −9.182 kcal/mol, respectively. An evaluation of binding conformation of ligand-bound protein complexes was performed with MD simulations for a time period of 30 ns along with free energy binding calculations using the g_mmpbsa technique. Prediction of inhibitory activities of the two lead compounds SEI (7.53) and ACI (6.84) using the 3D-QSAR model reaffirmed their inhibitory characteristics as potential anti-ataxia compounds.
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Affiliation(s)
- Siddharth Sinha
- Department of Biotechnology, TERI University New Delhi, India
| | - Sukriti Goyal
- Department of Bioscience and Biotechnology, Banasthali University Tonk, India
| | | | - Abhinav Grover
- School of Biotechnology, Jawaharlal Nehru University New Delhi, India
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Giunti P, Mantuano E, Frontali M, Veneziano L. Molecular mechanism of Spinocerebellar Ataxia type 6: glutamine repeat disorder, channelopathy and transcriptional dysregulation. The multifaceted aspects of a single mutation. Front Cell Neurosci 2015; 9:36. [PMID: 25762895 PMCID: PMC4329791 DOI: 10.3389/fncel.2015.00036] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 01/21/2015] [Indexed: 11/23/2022] Open
Abstract
Spinocerebellar Ataxia type 6 (SCA6) is an autosomal dominant neurodegenerative disease characterized by late onset, slowly progressive, mostly pure cerebellar ataxia. It is one of three allelic disorders associated to CACNA1A gene, coding for the Alpha1 A subunit of P/Q type calcium channel Cav2.1 expressed in the brain, particularly in the cerebellum. The other two disorders are Episodic Ataxia type 2 (EA2), and Familial Hemiplegic Migraine type 1 (FHM1). These disorders show distinct phenotypes that often overlap but have different pathogenic mechanisms. EA2 and FHM1 are due to mutations causing, respectively, a loss and a gain of channel function. SCA6, instead, is associated with short expansions of a polyglutamine stretch located in the cytoplasmic C-terminal tail of the protein. This domain has a relevant role in channel regulation, as well as in transcription regulation of other neuronal genes; thus the SCA6 CAG repeat expansion results in complex pathogenic molecular mechanisms reflecting the complex Cav2.1 C-terminus activity. We will provide a short review for an update on the SCA6 molecular mechanism.
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Affiliation(s)
- Paola Giunti
- Laboratory of Neurogenetics, Department of Molecular Neuroscience, UCL Institute of Neurology London, UK
| | - Elide Mantuano
- Laboratory of Neurogenetics, Institute of Translational Pharmacology, National Research Council of Italy Rome, Italy
| | - Marina Frontali
- Laboratory of Neurogenetics, Institute of Translational Pharmacology, National Research Council of Italy Rome, Italy
| | - Liana Veneziano
- Laboratory of Neurogenetics, Institute of Translational Pharmacology, National Research Council of Italy Rome, Italy
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Abstract
The cerebellum is an important structure for accurate control and timing of movement, and Purkinje neurons in the cerebellar cortex are key players in cerebellar motor control. Cerebellar dysfunction can result in ataxia, a disorder characterized by postural instability, gait disturbances and motor incoordination. Cerebellar ataxia is a symptom of a number of conditions, and the emerging evidence that Purkinje neuron dysfunction, in particular, abnormal Purkinje neuron repetitive firing, is a major driver of motor dysfunction in a subset of dominantly inherited ataxias is dicussed. Abnormalities in Purkinje neuron excitability that are observed in mouse models of each of these disorders, and where appropriate describe studies linking particular ion channels to aberrant excitability are also discussed. Common mechanisms of dysfunction and speculate about potential therapeutic targets, suggesting that Purkinje neuron firing abnormalities are a novel target for improving motor dysfunction in patients with some forms of dominantly inherited ataxia are proposed.
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Affiliation(s)
- Ravi Chopra
- Department of Neurology, University of Michigan, Alfred A Taubman Biomedical Science Research Building, Room 4009, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA
| | - Vikram G Shakkottai
- Department of Neurology, University of Michigan, Alfred A Taubman Biomedical Science Research Building, Room 4009, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA
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