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Tanaka M, Fujikawa R, Sekiguchi T, Hernandez J, Johnson OT, Tanaka D, Kumafuji K, Serikawa T, Hoang Trung H, Hattori K, Mashimo T, Kuwamura M, Gestwicki JE, Kuramoto T. A missense mutation in the Hspa8 gene encoding heat shock cognate protein 70 causes neuroaxonal dystrophy in rats. Front Neurosci 2024; 18:1263724. [PMID: 38384479 PMCID: PMC10880117 DOI: 10.3389/fnins.2024.1263724] [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: 07/20/2023] [Accepted: 01/16/2024] [Indexed: 02/23/2024] Open
Abstract
Neuroaxonal dystrophy (NAD) is a neurodegenerative disease characterized by spheroid (swollen axon) formation in the nervous system. In the present study, we focused on a newly established autosomal recessive mutant strain of F344-kk/kk rats with hind limb gait abnormalities and ataxia from a young age. Histopathologically, a number of axonal spheroids were observed throughout the central nervous system, including the spinal cord (mainly in the dorsal cord), brain stem, and cerebellum in F344-kk/kk rats. Transmission electron microscopic observation of the spinal cord revealed accumulation of electron-dense bodies, degenerated abnormal mitochondria, as well as membranous or tubular structures in the axonal spheroids. Based on these neuropathological findings, F344-kk/kk rats were diagnosed with NAD. By a positional cloning approach, we identified a missense mutation (V95E) in the Hspa8 (heat shock protein family A (Hsp70) member 8) gene located on chromosome 8 of the F344-kk/kk rat genome. Furthermore, we developed the Hspa8 knock-in (KI) rats with the V95E mutation using the CRISPR-Cas system. Homozygous Hspa8-KI rats exhibited ataxia and axonal spheroids similar to those of F344-kk/kk rats. The V95E mutant HSC70 protein exhibited the significant but modest decrease in the maximum hydrolysis rate of ATPase when stimulated by co-chaperons DnaJB4 and BAG1 in vitro, which suggests the functional deficit in the V95E HSC70. Together, our findings provide the first evidence that the genetic alteration of the Hspa8 gene caused NAD in mammals.
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Affiliation(s)
- Miyuu Tanaka
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan
- Laboratory of Veterinary Pathology, Graduate School of Veterinary Science, Osaka Metropolitan University, Izumisano, Osaka, Japan
| | - Ryoko Fujikawa
- Laboratory of Veterinary Pathology, Graduate School of Veterinary Science, Osaka Metropolitan University, Izumisano, Osaka, Japan
| | - Takahiro Sekiguchi
- Laboratory of Veterinary Pathology, Graduate School of Veterinary Science, Osaka Metropolitan University, Izumisano, Osaka, Japan
| | - Jason Hernandez
- Department of Pharmaceutical Chemistry and the Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, CA, United States
| | - Oleta T. Johnson
- Department of Pharmaceutical Chemistry and the Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, CA, United States
| | - Daisuke Tanaka
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Kenta Kumafuji
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Tadao Serikawa
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Hieu Hoang Trung
- Department of Animal Science, Faculty of Agriculture, Tokyo University of Agriculture, Atsugi, Kanagawa, Japan
| | - Kosuke Hattori
- Division of Animal Genetics, The Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo, Japan
| | - Tomoji Mashimo
- Division of Animal Genetics, The Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo, Japan
| | - Mitsuru Kuwamura
- Laboratory of Veterinary Pathology, Graduate School of Veterinary Science, Osaka Metropolitan University, Izumisano, Osaka, Japan
| | - Jason E. Gestwicki
- Department of Pharmaceutical Chemistry and the Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, CA, United States
| | - Takashi Kuramoto
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan
- Department of Animal Science, Faculty of Agriculture, Tokyo University of Agriculture, Atsugi, Kanagawa, Japan
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Cocostîrc V, Paștiu AI, Pusta DL. An Overview of Canine Inherited Neurological Disorders with Known Causal Variants. Animals (Basel) 2023; 13:3568. [PMID: 38003185 PMCID: PMC10668755 DOI: 10.3390/ani13223568] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 11/15/2023] [Accepted: 11/15/2023] [Indexed: 11/26/2023] Open
Abstract
Hereditary neurological conditions documented in dogs encompass congenital, neonatal, and late-onset disorders, along with both progressive and non-progressive forms. In order to identify the causal variant of a disease, the main two approaches are genome-wide investigations and candidate gene investigation. Online Mendelian Inheritance in Animals currently lists 418 Mendelian disorders specific to dogs, of which 355 have their likely causal genetic variant identified. This review aims to summarize the current knowledge on the canine nervous system phenes and their genetic causal variant. It has been noted that the majority of these diseases have an autosomal recessive pattern of inheritance. Additionally, the dog breeds that are more prone to develop such diseases are the Golden Retriever, in which six inherited neurological disorders with a known causal variant have been documented, and the Belgian Shepherd, in which five such disorders have been documented. DNA tests can play a vital role in effectively managing and ultimately eradicating inherited diseases.
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Affiliation(s)
- Vlad Cocostîrc
- Department of Genetics and Hereditary Diseases, Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, 400372 Cluj-Napoca, Romania; (A.I.P.); (D.L.P.)
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3
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Shen X, Sun P, Zhang H, Yang H. Mitochondrial quality control in the brain: The physiological and pathological roles. Front Neurosci 2022; 16:1075141. [PMID: 36578825 PMCID: PMC9791200 DOI: 10.3389/fnins.2022.1075141] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 11/24/2022] [Indexed: 12/14/2022] Open
Abstract
The human brain has high energetic expenses and consumes over 20% of total oxygen metabolism. Abnormal brain energy homeostasis leads to various brain diseases. Among multiple factors that contribute to these diseases, mitochondrial dysfunction is one of the most common causes. Maintenance of mitochondrial integrity and functionality is of pivotal importance to brain energy generation. Mitochondrial quality control (MQC), employing the coordination of multiple mechanisms, is evolved to overcome many mitochondrial defects. Thus, not surprisingly, aberrant mitochondrial quality control results in a wide range of brain disorders. Targeting MQC to preserve and restore mitochondrial function has emerged as a promising therapeutic strategy for the prevention and treatment of brain diseases. Here, we set out to summarize the current understanding of mitochondrial quality control in brain homeostasis. We also evaluate potential pharmaceutically and clinically relevant targets in MQC-associated brain disorders.
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Moura E, Tasqueti UI, Mangrich-Rocha RMV, Filho JRE, de Farias MR, Pimpão CT. Inborn Errors of Metabolism in Dogs: Historical, Metabolic, Genetic, and Clinical Aspects. Top Companion Anim Med 2022; 51:100731. [DOI: 10.1016/j.tcam.2022.100731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 09/11/2022] [Accepted: 10/14/2022] [Indexed: 11/06/2022]
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Chiaratti MR. Uncovering the important role of mitochondrial dynamics in oogenesis: impact on fertility and metabolic disorder transmission. Biophys Rev 2021; 13:967-981. [PMID: 35059021 PMCID: PMC8724343 DOI: 10.1007/s12551-021-00891-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 11/01/2021] [Indexed: 12/12/2022] Open
Abstract
Oocyte health is tightly tied to mitochondria given their role in energy production, metabolite supply, calcium (Ca2+) buffering, and cell death regulation, among others. In turn, mitochondrial function strongly relies on these organelle dynamics once cyclic events of fusion and fission (division) are required for mitochondrial turnover, positioning, content homogenization, metabolic flexibility, interaction with subcellular compartments, etc. Importantly, during oogenesis, mitochondria change their architecture from an "orthodox" elongated shape characterized by the presence of numerous transversely oriented cristae to a round-to-oval morphology containing arched and concentrically arranged cristae. This, along with evidence showing that mitochondrial function is kept quiescent during most part of oocyte development, suggests an important role of mitochondrial dynamics in oogenesis. To investigate this, recent works have downregulated/upregulated in oocytes the expression of key effectors of mitochondrial dynamics, including mitofusins 1 (MFN1) and 2 (MFN2) and the dynamin-related protein 1 (DRP1). As a result, both MFN1 and DRP1 were found to be essential to oogenesis and fertility, while MFN2 deletion led to offspring with increased weight gain and glucose intolerance. Curiously, neither MFN1/MFN2 deficiency nor DRP1 overexpression enhanced mitochondrial fragmentation, indicating that mitochondrial size is strictly regulated in oocytes. Therefore, the present work seeks to discuss the role of mitochondria in supporting oogenesis as well as recent findings connecting defective mitochondrial dynamics in oocytes with infertility and transmission of metabolic disorders.
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Affiliation(s)
- Marcos Roberto Chiaratti
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, 13565-905 Brazil
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Compound heterozygous PLA2G6 loss-of-function variants in Swaledale sheep with neuroaxonal dystrophy. Mol Genet Genomics 2020; 296:235-242. [PMID: 33159255 PMCID: PMC7840627 DOI: 10.1007/s00438-020-01742-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 10/23/2020] [Indexed: 10/28/2022]
Abstract
Sporadic occurrences of neurodegenerative disorders including neuroaxonal dystrophy (NAD) have been previously reported in sheep. However, so far no causative genetic variant has been found for ovine NAD. The aim of this study was to characterize the phenotype and the genetic aetiology of an early-onset neurodegenerative disorder observed in several lambs of purebred Swaledale sheep, a native English breed. Affected lambs showed progressive ataxia and stiff gait and subsequent histopathological analysis revealed the widespread presence of axonal spheroid indicating neuronal degeneration. Thus, the observed clinical phenotype could be explained by a novel form of NAD. After SNP genotyping and subsequent linkage mapping within a paternal half-sib pedigree with a total of five NAD-affected lambs, we identified two loss-of-function variants by whole-genome sequencing in the ovine PLA2G6 gene situated in a NAD-linked genome region on chromosome 3. All cases were carriers of a compound heterozygous splice site variant in intron 2 and a nonsense variant in exon 8. Herein we present evidence for the occurrence of a familial novel form of recessively inherited NAD in sheep due to allelic heterogeneity at PLA2G6. This study reports two pathogenic variants in PLA2G6 causing a novel form of NAD in Swaledale sheep which enables selection against this fatal disorder.
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Barthélémy I, Hitte C, Tiret L. The Dog Model in the Spotlight: Legacy of a Trustful Cooperation. J Neuromuscul Dis 2020; 6:421-451. [PMID: 31450509 PMCID: PMC6918919 DOI: 10.3233/jnd-190394] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Dogs have long been used as a biomedical model system and in particular as a preclinical proof of concept for innovative therapies before translation to humans. A recent example of the utility of this animal model is the promising myotubularin gene delivery in boys affected by X-linked centronuclear myopathy after successful systemic, long-term efficient gene therapy in Labrador retrievers. Mostly, this is due to unique features that make dogs an optimal system. The continuous emergence of spontaneous inherited disorders enables the identification of reliable complementary molecular models for human neuromuscular disorders (NMDs). Dogs’ characteristics including size, lifespan and unprecedented medical care level allow a comprehensive longitudinal description of diseases. Moreover, the highly similar pathogenic mechanisms with human patients yield to translational robustness. Finally, interindividual phenotypic heterogeneity between dogs helps identifying modifiers and anticipates precision medicine issues. This review article summarizes the present list of molecularly characterized dog models for NMDs and provides an exhaustive list of the clinical and paraclinical assays that have been developed. This toolbox offers scientists a sensitive and reliable system to thoroughly evaluate neuromuscular function, as well as efficiency and safety of innovative therapies targeting these NMDs. This review also contextualizes the model by highlighting its unique genetic value, shaped by the long-term coevolution of humans and domesticated dogs. Because the dog is one of the most protected research animal models, there is considerable opposition to include it in preclinical projects, posing a threat to the use of this model. We thus discuss ethical issues, emphasizing that unlike many other models, the dog also benefits from its contribution to comparative biomedical research with a drastic reduction in the prevalence of morbid alleles in the breeding stock and an improvement in medical care.
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Affiliation(s)
- Inès Barthélémy
- U955 - IMRB, Team 10 - Biology of the neuromuscular system, Inserm, UPEC, EFS, École nationale vétérinaire d'Alfort, Maisons-Alfort, France
| | - Christophe Hitte
- CNRS, University of Rennes 1, UMR 6290, IGDR, Faculty of Medicine, SFR Biosit, Rennes, France
| | - Laurent Tiret
- U955 - IMRB, Team 10 - Biology of the neuromuscular system, Inserm, UPEC, EFS, École nationale vétérinaire d'Alfort, Maisons-Alfort, France
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Chan DC. Mitochondrial Dynamics and Its Involvement in Disease. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2019; 15:235-259. [PMID: 31585519 DOI: 10.1146/annurev-pathmechdis-012419-032711] [Citation(s) in RCA: 610] [Impact Index Per Article: 122.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The dynamic properties of mitochondria-including their fusion, fission, and degradation-are critical for their optimal function in energy generation. The interplay of fusion and fission confers widespread benefits on mitochondria, including efficient transport, increased homogenization of the mitochondrial population, and efficient oxidative phosphorylation. These benefits arise through control of morphology, content exchange, equitable inheritance of mitochondria, maintenance of high-quality mitochondrial DNA, and segregation of damaged mitochondria for degradation. The key components of the machinery mediating mitochondrial fusion and fission belong to the dynamin family of GTPases that utilize GTP hydrolysis to drive mechanical work on biological membranes. Defects in this machinery cause a range of diseases that especially affect the nervous system. In addition, several common diseases, including neurodegenerative diseases and cancer, strongly affect mitochondrial dynamics.
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Affiliation(s)
- David C Chan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA;
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A Missense Mutation in the Vacuolar Protein Sorting 11 ( VPS11) Gene Is Associated with Neuroaxonal Dystrophy in Rottweiler Dogs. G3-GENES GENOMES GENETICS 2018; 8:2773-2780. [PMID: 29945969 PMCID: PMC6071611 DOI: 10.1534/g3.118.200376] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Canine neuroaxonal dystrophy (NAD) is a recessive, degenerative neurological disease of young adult Rottweiler dogs (Canis lupus familiaris) characterized pathologically by axonal spheroids primarily targeting sensory axon terminals. A genome-wide association study of seven Rottweilers affected with NAD and 42 controls revealed a significantly associated region on canine chromosome 5 (CFA 5). Homozygosity within the associated region narrowed the critical interval to a 4.46 Mb haplotype (CFA5:11.28 Mb – 15.75 Mb; CanFam3.1) that associated with the phenotype. Whole-genome sequencing of two histopathologically confirmed canine NAD cases and 98 dogs unaffected with NAD revealed a homozygous missense mutation within the Vacuolar Protein Sorting 11 (VPS11) gene (g.14777774T > C; p.H835R) that was associated with the phenotype. These findings present the opportunity for an antemortem test for confirming NAD in Rottweilers where the allele frequency was estimated at 2.3%. VPS11 mutations have been associated with a degenerative leukoencephalopathy in humans, and VSP11 should additionally be included as a candidate gene for unexplained cases of human NAD.
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10
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Pla2g6 Deficiency in Zebrafish Leads to Dopaminergic Cell Death, Axonal Degeneration, Increased β-Synuclein Expression, and Defects in Brain Functions and Pathways. Mol Neurobiol 2018; 55:6734-6754. [PMID: 29344929 DOI: 10.1007/s12035-017-0846-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 12/18/2017] [Indexed: 10/18/2022]
Abstract
This study aimed to gain insights into the pathophysiology underlying PLA2G6-associated neurodegeneration that is implicated in three different neurological disorders, suggesting that other, unknown genetic or environmental factors might contribute to its wide phenotypic expression. To accomplish this, we downregulated the function of pla2g6 in the zebrafish nervous system, performed parkinsonism-related phenotypic characterization, and determined the effects of gene regulation upon the loss of pla2g6 function by using RNA sequencing and downstream analyses. Pla2g6 deficiency resulted in axonal degeneration, dopaminergic and motor neuron cell loss, and increased β-synuclein expression. We also observed that many of the identified, differentially expressed genes were implicated in other brain disorders, which might explain the variable phenotypic expression of pla2g6-associated disease, and found that top enriched canonical pathways included those already known or suggested to play a major role in the pathogenesis of Parkinson's disease. Our data support that pla2g6 is relevant for cranial motor development with significant implications in the pathophysiology underlying Parkinson's disease.
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11
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Tanaka M, Yamaguchi S, Akiyoshi H, Tsuboi M, Uchida K, Izawa T, Yamate J, Kuwamura M. Ultrastructural features of canine neuroaxonal dystrophy in a Papillon dog. J Vet Med Sci 2017; 79:1927-1930. [PMID: 28993562 PMCID: PMC5745166 DOI: 10.1292/jvms.17-0487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Neuroaxonal dystrophy (NAD) is a neurodegenerative disease characterized by severe axonal swelling (spheroids) throughout the nervous system. In dogs, NAD has been reported in several breeds and a missense mutation in PLA2G6 gene has recently been identified in the Papillon dog NAD. Here we performed ultrastructural analysis to clarify the detailed ultrastructural features of the Papillon dog NAD. Dystrophic axons consisted of accumulation of filamentous materials, tubulovesicular structures, and swollen edematous mitochondria with degenerated inner membranes were often observed in the central nervous system. At axonal terminals, degeneration of presynaptic membrane was also detected. As reported in Pla2g6 knockout mice, mitochondrial and presynaptic degeneration may be related with the pathogenesis of NAD in Papillon dogs.
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Affiliation(s)
- Miyuu Tanaka
- Laboratory of Veterinary Pathology, Graduate School of Life and Environmental Science, Osaka Prefecture University, Rinkuu Ourai Kita 1-58, Izumisano, Osaka 598-8531, Japan
| | - Shinobu Yamaguchi
- Hataeda Animal Hospital, 680 Iwakura Hataedacho, Sakyo-ku, Kyoto 606-0015, Japan
| | - Hideo Akiyoshi
- Laboratory of Veterinary Surgery, Graduate School of Life and Environmental Science, Osaka Prefecture University, Rinkuu Ourai Kita 1-58, Izumisano, Osaka 598-8531, Japan
| | - Masaya Tsuboi
- Laboratory of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan
| | - Kazuyuki Uchida
- Laboratory of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan
| | - Takeshi Izawa
- Laboratory of Veterinary Pathology, Graduate School of Life and Environmental Science, Osaka Prefecture University, Rinkuu Ourai Kita 1-58, Izumisano, Osaka 598-8531, Japan
| | - Jyoji Yamate
- Laboratory of Veterinary Pathology, Graduate School of Life and Environmental Science, Osaka Prefecture University, Rinkuu Ourai Kita 1-58, Izumisano, Osaka 598-8531, Japan
| | - Mitsuru Kuwamura
- Laboratory of Veterinary Pathology, Graduate School of Life and Environmental Science, Osaka Prefecture University, Rinkuu Ourai Kita 1-58, Izumisano, Osaka 598-8531, Japan
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Gurda BL, Bradbury AM, Vite CH. Canine and Feline Models of Human Genetic Diseases and Their Contributions to Advancing Clinical Therapies
. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2017; 90:417-431. [PMID: 28955181 PMCID: PMC5612185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
For many lethal or debilitating genetic disorders in patients there are no satisfactory therapies. Several barriers exist that hinder the developments of effective therapies including the limited availability of clinically relevant animal models that faithfully recapitulate human genetic disease. In 1974, the Referral Center for Animal Models of Human Genetic Disease (RCAM) was established by Dr. Donald F. Patterson and continued by Dr. Mark E. Haskins at the University of Pennsylvania with the mission to discover, understand, treat, and maintain breeding colonies of naturally occurring hereditary disorders in dogs and cats that are orthologous to those found in human patients. Although non-human primates, sheep, and pig models are also available within the medical community, naturally occurring diseases are rarely identified in non-human primates, and the vast behavioral, clinicopathological, physiological, and anatomical knowledge available regarding dogs and cats far surpasses what is available in ovine and porcine species. The canine and feline models that are maintained at RCAM are presented here with a focus on preclinical therapy data. Clinical studies that have been generated from preclinical work in these models are also presented.
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Affiliation(s)
| | | | - Charles H. Vite
- To whom all correspondence should be addressed: Dr. Charles H. Vite, 209 Rosenthal Building, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, Tel: 215-898-9473, .
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Bovine and murine models highlight novel roles for SLC25A46 in mitochondrial dynamics and metabolism, with implications for human and animal health. PLoS Genet 2017; 13:e1006597. [PMID: 28376083 PMCID: PMC5380314 DOI: 10.1371/journal.pgen.1006597] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 01/21/2017] [Indexed: 12/11/2022] Open
Abstract
Neuropathies are neurodegenerative diseases affecting humans and other mammals. Many genetic causes have been identified so far, including mutations of genes encoding proteins involved in mitochondrial dynamics. Recently, the “Turning calves syndrome”, a novel sensorimotor polyneuropathy was described in the French Rouge-des-Prés cattle breed. In the present study, we determined that this hereditary disease resulted from a single nucleotide substitution in SLC25A46, a gene encoding a protein of the mitochondrial carrier family. This mutation caused an apparent damaging amino-acid substitution. To better understand the function of this protein, we knocked out the Slc25a46 gene in a mouse model. This alteration affected not only the nervous system but also altered general metabolism, resulting in premature mortality. Based on optic microscopy examination, electron microscopy and on biochemical, metabolic and proteomic analyses, we showed that the Slc25a46 disruption caused a fusion/fission imbalance and an abnormal mitochondrial architecture that disturbed mitochondrial metabolism. These data extended the range of phenotypes associated with Slc25a46 dysfunction. Moreover, this Slc25a46 knock-out mouse model should be useful to further elucidate the role of SLC25A46 in mitochondrial dynamics. Mitochondria are essential organelles, the site of numerous biochemical reactions, with a critical role in delivering energy to cells, particularly in the nervous system. Consequently, disrupted mitochondrial function often results in neurodegenerative diseases, in humans and in other mammals. Herein, we determined that the “Turning calves syndrome”, a new hereditary sensorimotor polyneuropathy in the French Rouge-des-Prés cattle breed was due to a single substitution in SLC25A46, a gene encoding a protein of the mitochondrial carrier family. We created a mouse knock-out model and determined that disruption of this gene dramatically disturbed mitochondrial dynamics in various organs that resulted in altered metabolism and early death, indirectly confirming the gene identification in cattle. Moreover, our novel findings extended the range of phenotypes associated with polymorphisms of this gene and help to elucidate the role of SLC25A46 in mitochondrial function.
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Hahn K, Rohdin C, Jagannathan V, Wohlsein P, Baumgärtner W, Seehusen F, Spitzbarth I, Grandon R, Drögemüller C, Jäderlund KH. TECPR2 Associated Neuroaxonal Dystrophy in Spanish Water Dogs. PLoS One 2015; 10:e0141824. [PMID: 26555167 PMCID: PMC4640708 DOI: 10.1371/journal.pone.0141824] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 10/13/2015] [Indexed: 12/16/2022] Open
Abstract
Clinical, pathological and genetic examination revealed an as yet uncharacterized juvenile-onset neuroaxonal dystrophy (NAD) in Spanish water dogs. Affected dogs presented with various neurological deficits including gait abnormalities and behavioral deficits. Histopathology demonstrated spheroid formation accentuated in the grey matter of the cerebral hemispheres, the cerebellum, the brain stem and in the sensory pathways of the spinal cord. Iron accumulation was absent. Ultrastructurally spheroids contained predominantly closely packed vesicles with a double-layered membrane, which were characterized as autophagosomes using immunohistochemistry. The family history of the four affected dogs suggested an autosomal recessive inheritance. SNP genotyping showed a single genomic region of extended homozygosity of 4.5 Mb in the four cases on CFA 8. Linkage analysis revealed a maximal parametric LOD score of 2.5 at this region. By whole genome re-sequencing of one affected dog, a perfectly associated, single, non-synonymous coding variant in the canine tectonin beta-propeller repeat-containing protein 2 (TECPR2) gene affecting a highly conserved region was detected (c.4009C>T or p.R1337W). This canine NAD form displays etiologic parallels to an inherited TECPR2 associated type of human hereditary spastic paraparesis (HSP). In contrast to the canine NAD, the spinal cord lesions in most types of human HSP involve the sensory and the motor pathways. Furthermore, the canine NAD form reveals similarities to cases of human NAD defined by widespread spheroid formation without iron accumulation in the basal ganglia. Thus TECPR2 should also be considered as candidate gene for human NAD. Immunohistochemistry and the ultrastructural findings further support the assumption, that TECPR2 regulates autophagosome accumulation in the autophagic pathways. Consequently, this report provides the first genetic characterization of juvenile canine NAD, describes the histopathological features associated with the TECPR2 mutation and provides evidence to emphasize the association between failure of autophagy and neurodegeneration.
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Affiliation(s)
- Kerstin Hahn
- University of Veterinary Medicine Hannover, Department of Pathology, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Cecilia Rohdin
- University Animal Hospital, Swedish University of Agricultural Sciences, Uppsala, Sweden
- Anicura, Albano Small Animal Hospital, Danderyd, Sweden
| | - Vidhya Jagannathan
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Peter Wohlsein
- University of Veterinary Medicine Hannover, Department of Pathology, Hannover, Germany
| | - Wolfgang Baumgärtner
- University of Veterinary Medicine Hannover, Department of Pathology, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Frauke Seehusen
- University of Veterinary Medicine Hannover, Department of Pathology, Hannover, Germany
| | - Ingo Spitzbarth
- University of Veterinary Medicine Hannover, Department of Pathology, Hannover, Germany
| | - Rodrigo Grandon
- Department of Biomedical Sciences and Veterinary Public Health, Division of Pathology, Pharmacology and Toxicology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Cord Drögemüller
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- * E-mail:
| | - Karin Hultin Jäderlund
- Department of Companion Animal Clinical Sciences, Norwegian University of Life Sciences, Oslo, Norway
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O'Brien DP, Leeb T. DNA testing in neurologic diseases. J Vet Intern Med 2014; 28:1186-98. [PMID: 24962505 PMCID: PMC4857950 DOI: 10.1111/jvim.12383] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 04/03/2014] [Accepted: 04/23/2014] [Indexed: 12/24/2022] Open
Abstract
DNA testing is available for a growing number of hereditary diseases in neurology and other specialties. In addition to guiding breeding decisions, DNA tests are important tools in the diagnosis of diseases, particularly in conditions for which clinical signs are relatively nonspecific. DNA testing also can provide valuable insight into the risk of hereditary disease when decisions about treating comorbidities are being made. Advances in technology and bioinformatics will make broad screening for potential disease-causing mutations available soon. As DNA tests come into more common use, it is critical that clinicians understand the proper application and interpretation of these test results.
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Affiliation(s)
- D P O'Brien
- Department Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO
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Adeno-associated virus serotypes 9 and rh10 mediate strong neuronal transduction of the dog brain. Gene Ther 2013; 21:28-36. [PMID: 24131981 PMCID: PMC3881028 DOI: 10.1038/gt.2013.54] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 08/23/2013] [Accepted: 08/28/2013] [Indexed: 12/20/2022]
Abstract
Canine models have many advantages for evaluating therapy of human central nervous system (CNS) diseases. In contrast to nonhuman primate models, naturally occurring canine CNS diseases are common. In contrast to murine models, the dog's lifespan is long, its brain is large and the diseases affecting it commonly have the same molecular, pathological and clinical phenotype as the human diseases. We compared the ability of four intracerebrally injected adeno-associated virus vector (AAV) serotypes to transduce the dog brain with green fluorescent protein as the first step in using these vectors to evaluate both delivery and efficacy in naturally occurring canine homologs of human diseases. Quantitative measures of transduction, maximum diameter and area, identified both AAV2/9 and AAV2/rh10 as significantly more efficient than either AAV2/1 or AAV2/5 at transducing cerebral cortex, caudate nucleus, thalamus and internal capsule. Fluorescence co-labeling with cell-type-specific antibodies demonstrated that AAV2/9 and AAV2/rh10 were capable of primarily transducing neurons, although glial transduction was also identified and found to be more efficient with the AAV2/9 vector. These data are a prerequisite to evaluating the efficacy of recombinant AAV vectors carrying disease-modifying transgenes to treat naturally occurring canine models in preclinical studies of human CNS disease therapy.
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Chapman AL, Bennett EJ, Ramesh TM, De Vos KJ, Grierson AJ. Axonal Transport Defects in a Mitofusin 2 Loss of Function Model of Charcot-Marie-Tooth Disease in Zebrafish. PLoS One 2013; 8:e67276. [PMID: 23840650 PMCID: PMC3694133 DOI: 10.1371/journal.pone.0067276] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 05/16/2013] [Indexed: 02/06/2023] Open
Abstract
Charcot-Marie-Tooth disease (CMT) represents a group of neurodegenerative disorders typically characterised by demyelination (CMT1) or distal axon degeneration (CMT2) of motor and sensory neurons. The majority of CMT2 cases are caused by mutations in mitofusin 2 (MFN2); an essential gene encoding a protein responsible for fusion of the mitochondrial outer membrane. The mechanism of action of MFN2 mutations is still not fully resolved. To investigate a role for loss of Mfn2 function in disease we investigated an ENU-induced nonsense mutation in zebrafish MFN2 and characterised the phenotype of these fish at the whole organism, pathological, and subcellular level. We show that unlike mice, loss of MFN2 function in zebrafish leads to an adult onset, progressive phenotype with predominant symptoms of motor dysfunction similar to CMT2. Mutant zebrafish show progressive loss of swimming associated with alterations at the neuro-muscular junction. At the cellular level, we provide direct evidence that mitochondrial transport along axons is perturbed in Mfn2 mutant zebrafish, suggesting that this is a key mechanism of disease in CMT. The progressive phenotype and pathology suggest that zebrafish will be useful for further investigating the disease mechanism and potential treatment of axonal forms of CMT. Our findings support the idea that MFN2 mutation status should be investigated in patients presenting with early-onset recessively inherited axonal CMT.
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Affiliation(s)
- Anna L. Chapman
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Ellen J. Bennett
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Tennore M. Ramesh
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Kurt J. De Vos
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Andrew J. Grierson
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
- Medical Research Council Centre for Developmental and Biomedical Genetics, University of Sheffield, Sheffield, United Kingdom
- * E-mail:
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Köroğlu Ç, Seven M, Tolun A. Recessive truncating NALCN mutation in infantile neuroaxonal dystrophy with facial dysmorphism. J Med Genet 2013; 50:515-20. [PMID: 23749988 DOI: 10.1136/jmedgenet-2013-101634] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Infantile neuroaxonal dystrophy (INAD) is a recessive disease that results in total neurological degeneration and death in childhood. PLA2G6 mutation is the underlying genetic defect, but rare genetic heterogeneity has been demonstrated. One of the five families we studied did not link to PLA2G6 locus, and in the family one of the two affected siblings additionally had atypical features including facial dysmorphism, pectus carinatum, scoliosis, pes varus, zygodactyly and bilateral cryptorchidism as well as cerebellar atrophy, as previously reported. METHODS Sural biopsy was investigated by electron microscopy. PLA2G6 was screened for mutations by Sanger sequencing. In the mutation-free family, candidate disease loci were found via linkage analysis using data from single nucleotide polymorphism genome scans. Exome sequencing was applied to find the variants at the loci. RESULTS PLA2G6 mutations were identified in four families including the one with an unusually severe phenotype that led to death within the first 2 years of life. In the remaining family, seven candidate loci totalling 15.2 Mb were found and a homozygous truncating mutation p.Q642X was identified in NALCN at 13q32.3. The patients are around 20-years-old. CONCLUSIONS NALCN is the gene responsible for INAD with facial dysmorphism. The patients have lived to adulthood despite severe growth and neuromotor retardation. NALCN forms a voltage-independent ion channel with a role in the regulation of neuronal excitability. Our findings broaden the spectrum of genes associated with neuroaxonal dystrophy. Testing infants with idiopathic severe growth retardation and neurodegeneration for NALCN mutations could benefit families.
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Affiliation(s)
- Çiğdem Köroğlu
- Department of Molecular Biology and Genetics, Boğaziçi University, Istanbul, Turkey
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Abstract
Mitochondria are dynamic organelles that continually undergo fusion and fission. These opposing processes work in concert to maintain the shape, size, and number of mitochondria and their physiological function. Some of the major molecules mediating mitochondrial fusion and fission in mammals have been discovered, but the underlying molecular mechanisms are only partially unraveled. In particular, the cast of characters involved in mitochondrial fission needs to be clarified. By enabling content mixing between mitochondria, fusion and fission serve to maintain a homogeneous and healthy mitochondrial population. Mitochondrial dynamics has been linked to multiple mitochondrial functions, including mitochondrial DNA stability, respiratory capacity, apoptosis, response to cellular stress, and mitophagy. Because of these important functions, mitochondrial fusion and fission are essential in mammals, and even mild defects in mitochondrial dynamics are associated with disease. A better understanding of these processes likely will ultimately lead to improvements in human health.
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Affiliation(s)
- David C Chan
- Division of Biology and the Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California 91125, USA.
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