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Koeberl DD, Koch RL, Lim JA, Brooks ED, Arnson BD, Sun B, Kishnani PS. Gene therapy for glycogen storage diseases. J Inherit Metab Dis 2024; 47:93-118. [PMID: 37421310 PMCID: PMC10874648 DOI: 10.1002/jimd.12654] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 05/24/2023] [Accepted: 07/05/2023] [Indexed: 07/10/2023]
Abstract
Glycogen storage disorders (GSDs) are inherited disorders of metabolism resulting from the deficiency of individual enzymes involved in the synthesis, transport, and degradation of glycogen. This literature review summarizes the development of gene therapy for the GSDs. The abnormal accumulation of glycogen and deficiency of glucose production in GSDs lead to unique symptoms based upon the enzyme step and tissues involved, such as liver and kidney involvement associated with severe hypoglycemia during fasting and the risk of long-term complications including hepatic adenoma/carcinoma and end stage kidney disease in GSD Ia from glucose-6-phosphatase deficiency, and cardiac/skeletal/smooth muscle involvement associated with myopathy +/- cardiomyopathy and the risk for cardiorespiratory failure in Pompe disease. These symptoms are present to a variable degree in animal models for the GSDs, which have been utilized to evaluate new therapies including gene therapy and genome editing. Gene therapy for Pompe disease and GSD Ia has progressed to Phase I and Phase III clinical trials, respectively, and are evaluating the safety and bioactivity of adeno-associated virus vectors. Clinical research to understand the natural history and progression of the GSDs provides invaluable outcome measures that serve as endpoints to evaluate benefits in clinical trials. While promising, gene therapy and genome editing face challenges with regard to clinical implementation, including immune responses and toxicities that have been revealed during clinical trials of gene therapy that are underway. Gene therapy for the glycogen storage diseases is under development, addressing an unmet need for specific, stable therapy for these conditions.
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Affiliation(s)
- Dwight D. Koeberl
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical School, Durham, NC, United States
- Department of Molecular Genetics & Microbiology, Duke University Medical Center, Durham, NC, United States
| | - Rebecca L. Koch
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical School, Durham, NC, United States
| | - Jeong-A Lim
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical School, Durham, NC, United States
| | - Elizabeth D. Brooks
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical School, Durham, NC, United States
| | - Benjamin D. Arnson
- Department of Molecular Genetics & Microbiology, Duke University Medical Center, Durham, NC, United States
| | - Baodong Sun
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical School, Durham, NC, United States
| | - Priya S. Kishnani
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical School, Durham, NC, United States
- Department of Molecular Genetics & Microbiology, Duke University Medical Center, Durham, NC, United States
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2
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Oikonomidis IL, Milne E. Clinical enzymology of the dog and cat. Aust Vet J 2023; 101:465-478. [PMID: 37767749 DOI: 10.1111/avj.13291] [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: 04/04/2023] [Revised: 08/15/2023] [Accepted: 09/10/2023] [Indexed: 09/29/2023]
Abstract
Clinical enzymology studies the enzyme activity in serum or other body fluids for the diagnosis, prognosis or monitoring of a variety of diseases. Clinical enzymology has greatly benefited from advances in technology and is now an integral part of laboratory analysis. However, to maximise the clinical benefits of serum enzyme measurement, clinicians and clinical pathologists must have a good understanding of the pathophysiology behind serum enzyme alterations. They must also be aware of the preanalytical and analytical factors that can affect the accuracy of serum enzyme activity measurement. This review article first covers the basic concepts of clinical enzymology and the general mechanisms related to serum enzyme alterations. Then, the review discusses the potential effects of various preanalytical and analytical factors on enzyme activity measurement. Lastly, it explores the pathophysiology and clinical use of various serum enzymes in canine and feline medicine. The present review article aims to be a comprehensive one-stop source for clinical pathologists and small animal practitioners.
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Affiliation(s)
- I L Oikonomidis
- Easter Bush Pathology, The Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Midlothian, United Kingdom
| | - E Milne
- Easter Bush Pathology, The Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Midlothian, United Kingdom
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3
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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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Almodóvar-Payá A, Villarreal-Salazar M, de Luna N, Nogales-Gadea G, Real-Martínez A, Andreu AL, Martín MA, Arenas J, Lucia A, Vissing J, Krag T, Pinós T. Preclinical Research in Glycogen Storage Diseases: A Comprehensive Review of Current Animal Models. Int J Mol Sci 2020; 21:ijms21249621. [PMID: 33348688 PMCID: PMC7766110 DOI: 10.3390/ijms21249621] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/11/2020] [Accepted: 12/15/2020] [Indexed: 12/19/2022] Open
Abstract
GSD are a group of disorders characterized by a defect in gene expression of specific enzymes involved in glycogen breakdown or synthesis, commonly resulting in the accumulation of glycogen in various tissues (primarily the liver and skeletal muscle). Several different GSD animal models have been found to naturally present spontaneous mutations and others have been developed and characterized in order to further understand the physiopathology of these diseases and as a useful tool to evaluate potential therapeutic strategies. In the present work we have reviewed a total of 42 different animal models of GSD, including 26 genetically modified mouse models, 15 naturally occurring models (encompassing quails, cats, dogs, sheep, cattle and horses), and one genetically modified zebrafish model. To our knowledge, this is the most complete list of GSD animal models ever reviewed. Importantly, when all these animal models are analyzed together, we can observe some common traits, as well as model specific differences, that would be overlooked if each model was only studied in the context of a given GSD.
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Affiliation(s)
- Aitana Almodóvar-Payá
- Mitochondrial and Neuromuscular Disorders Unit, Vall d’Hebron Institut de Recerca, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (A.A.-P.); (M.V.-S.); (A.R.-M.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (N.d.L.); (G.N.-G.); (M.A.M.); (J.A.)
| | - Mónica Villarreal-Salazar
- Mitochondrial and Neuromuscular Disorders Unit, Vall d’Hebron Institut de Recerca, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (A.A.-P.); (M.V.-S.); (A.R.-M.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (N.d.L.); (G.N.-G.); (M.A.M.); (J.A.)
| | - Noemí de Luna
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (N.d.L.); (G.N.-G.); (M.A.M.); (J.A.)
- Laboratori de Malalties Neuromusculars, Institut de Recerca Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, 08041 Barcelona, Spain
| | - Gisela Nogales-Gadea
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (N.d.L.); (G.N.-G.); (M.A.M.); (J.A.)
- Grup de Recerca en Malalties Neuromusculars i Neuropediàtriques, Department of Neurosciences, Institut d’Investigacio en Ciencies de la Salut Germans Trias i Pujol i Campus Can Ruti, Universitat Autònoma de Barcelona, 08916 Badalona, Spain
| | - Alberto Real-Martínez
- Mitochondrial and Neuromuscular Disorders Unit, Vall d’Hebron Institut de Recerca, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (A.A.-P.); (M.V.-S.); (A.R.-M.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (N.d.L.); (G.N.-G.); (M.A.M.); (J.A.)
| | - Antoni L. Andreu
- EATRIS, European Infrastructure for Translational Medicine, 1081 HZ Amsterdam, The Netherlands;
| | - Miguel Angel Martín
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (N.d.L.); (G.N.-G.); (M.A.M.); (J.A.)
- Mitochondrial and Neuromuscular Diseases Laboratory, 12 de Octubre Hospital Research Institute (i+12), 28041 Madrid, Spain
| | - Joaquin Arenas
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (N.d.L.); (G.N.-G.); (M.A.M.); (J.A.)
- Mitochondrial and Neuromuscular Diseases Laboratory, 12 de Octubre Hospital Research Institute (i+12), 28041 Madrid, Spain
| | - Alejandro Lucia
- Faculty of Sport Sciences, European University, 28670 Madrid, Spain;
| | - John Vissing
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, DK-2100 Copenhagen, Denmark; (J.V.); (T.K.)
| | - Thomas Krag
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, DK-2100 Copenhagen, Denmark; (J.V.); (T.K.)
| | - Tomàs Pinós
- Mitochondrial and Neuromuscular Disorders Unit, Vall d’Hebron Institut de Recerca, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (A.A.-P.); (M.V.-S.); (A.R.-M.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (N.d.L.); (G.N.-G.); (M.A.M.); (J.A.)
- Correspondence: ; Tel.: +34-934894057
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Cook S, McKenna M, Glanemann B, Sandhu R, Scudder C. Suspected congenital hyperinsulinism in a Shiba Inu dog. J Vet Intern Med 2020; 34:2086-2090. [PMID: 32592436 PMCID: PMC7517843 DOI: 10.1111/jvim.15834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 05/31/2020] [Accepted: 06/03/2020] [Indexed: 12/02/2022] Open
Abstract
A 3‐month‐old male intact Shiba Inu dog was evaluated for a seizure disorder initially deemed idiopathic in origin. Seizure frequency remained unchanged despite therapeutic serum phenobarbital concentration and use of levetiracetam. The dog was documented to be markedly hypoglycemic during a seizure episode on reevaluation at 6 months of age. Serum insulin concentrations during hypoglycemia were 41 U/μL (reference range, 10‐29 U/μL). The dog was transitioned to 4 times per day feeding, diazoxide was started at 3.5 mg/kg PO q8h, and antiepileptic drugs were discontinued. No clinically relevant abnormalities were identified on bicavitary arterial and venous phase contrast computed tomographic imaging. The dog remained seizure‐free and clinically normal at 3 years of age while receiving 5.5 mg/kg diazoxide PO q12h and twice daily feeding. Seizures later occurred approximately twice per year and after exertion, with or without vomiting of a diazoxide dose. Blood glucose curves and interstitial glucose monitoring were used to titrate diazoxide dose and dosing interval. Congenital hyperinsulinism is well recognized in people but has not been reported in veterinary medicine.
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Affiliation(s)
- Simon Cook
- Department of Clinical Science and Services Royal Veterinary College London United Kingdom
| | - Myles McKenna
- Department of Clinical Science and Services Royal Veterinary College London United Kingdom
| | - Barbara Glanemann
- Department of Clinical Science and Services Royal Veterinary College London United Kingdom
| | | | - Chris Scudder
- Department of Comparative Biomedical Sciences Royal Veterinary College London United Kingdom
- Southfields Veterinary Specialists Laindon, Essex United Kingdom
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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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7
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Quinlivan R, Andreu AL, Marti R. 211th ENMC International Workshop:: Development of diagnostic criteria and management strategies for McArdle Disease and related rare glycogenolytic disorders to improve standards of care. 17-19 April 2015, Naarden, The Netherlands. Neuromuscul Disord 2017; 27:1143-1151. [PMID: 29079393 DOI: 10.1016/j.nmd.2017.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 09/04/2017] [Indexed: 11/17/2022]
Affiliation(s)
- Ros Quinlivan
- MRC Centre for Neuromuscular Disease, National Hospital for Neurology and Neurosurgery, London, UK.
| | - Antoni L Andreu
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, CIBERER, Barcelona, Catalonia, Spain
| | - Ramon Marti
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, CIBERER, Barcelona, Catalonia, Spain
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8
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Maile CA, Hingst JR, Mahalingan KK, O'Reilly AO, Cleasby ME, Mickelson JR, McCue ME, Anderson SM, Hurley TD, Wojtaszewski JFP, Piercy RJ. A highly prevalent equine glycogen storage disease is explained by constitutive activation of a mutant glycogen synthase. Biochim Biophys Acta Gen Subj 2016; 1861:3388-3398. [PMID: 27592162 DOI: 10.1016/j.bbagen.2016.08.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 08/15/2016] [Accepted: 08/30/2016] [Indexed: 01/16/2023]
Abstract
BACKGROUND Equine type 1 polysaccharide storage myopathy (PSSM1) is associated with a missense mutation (R309H) in the glycogen synthase (GYS1) gene, enhanced glycogen synthase (GS) activity and excessive glycogen and amylopectate inclusions in muscle. METHODS Equine muscle biochemical and recombinant enzyme kinetic assays in vitro and homology modelling in silico, were used to investigate the hypothesis that higher GS activity in affected horse muscle is caused by higher GS expression, dysregulation, or constitutive activation via a conformational change. RESULTS PSSM1-affected horse muscle had significantly higher glycogen content than control horse muscle despite no difference in GS expression. GS activity was significantly higher in muscle from homozygous mutants than from heterozygote and control horses, in the absence and presence of the allosteric regulator, glucose 6 phosphate (G6P). Muscle from homozygous mutant horses also had significantly increased GS phosphorylation at sites 2+2a and significantly higher AMPKα1 (an upstream kinase) expression than controls, likely reflecting a physiological attempt to reduce GS enzyme activity. Recombinant mutant GS was highly active with a considerably lower Km for UDP-glucose, in the presence and absence of G6P, when compared to wild type GS, and despite its phosphorylation. CONCLUSIONS Elevated activity of the mutant enzyme is associated with ineffective regulation via phosphorylation rendering it constitutively active. Modelling suggested that the mutation disrupts a salt bridge that normally stabilises the basal state, shifting the equilibrium to the enzyme's active state. GENERAL SIGNIFICANCE This study explains the gain of function pathogenesis in this highly prevalent polyglucosan myopathy.
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Affiliation(s)
- C A Maile
- Comparative Neuromuscular Diseases Laboratory, Department of Clinical Sciences and Services, Royal Veterinary College, London, UK
| | - J R Hingst
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Denmark
| | - K K Mahalingan
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, USA
| | - A O O'Reilly
- School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, UK
| | - M E Cleasby
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - J R Mickelson
- Veterinary Biomedical Sciences Department, University of Minnesota, St. Paul, MN, USA
| | - M E McCue
- Veterinary Population Medicine Department, University of Minnesota, St. Paul, MN, USA
| | - S M Anderson
- Veterinary Population Medicine Department, University of Minnesota, St. Paul, MN, USA
| | - T D Hurley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, USA
| | - J F P Wojtaszewski
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Denmark
| | - R J Piercy
- Comparative Neuromuscular Diseases Laboratory, Department of Clinical Sciences and Services, Royal Veterinary College, London, UK.
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Brooks ED, Koeberl DD. Large animal models and new therapies for glycogen storage disease. J Inherit Metab Dis 2015; 38:505-9. [PMID: 25224826 PMCID: PMC4513910 DOI: 10.1007/s10545-014-9766-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Revised: 08/13/2014] [Accepted: 08/25/2014] [Indexed: 10/24/2022]
Abstract
Glycogen storage diseases (GSD), a unique category of inherited metabolic disorders, were first described early in the twentieth century. Since then, the biochemical and genetic bases of these disorders have been determined, and an increasing number of animal models for GSD have become available. At least seven large mammalian models have been developed for laboratory research on GSDs. These models have facilitated the development of new therapies, including gene therapy, which are undergoing clinical translation. For example, gene therapy prolonged survival and prevented hypoglycemia during fasting for greater than one year in dogs with GSD type Ia, and the need for periodic re-administration to maintain efficacy was demonstrated in that dog model. The further development of gene therapy could provide curative therapy for patients with GSD and other inherited metabolic disorders.
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Affiliation(s)
- Elizabeth D Brooks
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
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10
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Glycogen storage disease type III: A novel Agl knockout mouse model. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2318-28. [PMID: 25092169 DOI: 10.1016/j.bbadis.2014.07.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 07/11/2014] [Accepted: 07/28/2014] [Indexed: 12/29/2022]
Abstract
Glycogen storage disease type III is an autosomal recessive disease characterized by a deficiency in the glycogen debranching enzyme, encoded by AGL. Essential features of this disease are hepatomegaly, hypoglycemia, hyperlipidemia, and growth retardation. Progressive skeletal myopathy, neuropathy, and/or cardiomyopathy become prominent in adults. Currently, there is no available cure. We generated an Agl knockout mouse model by deletion of the carboxy terminus of the protein, including the carboxy end of the glucosidase domain and the glycogen-binding domain. Agl knockout mice presented serious hepatomegaly, but we did not observe signs of cirrhosis or adenomas. In affected tissues, glycogen storage was higher than in wild-type mice, even in the central nervous system which has never been tested in GSDIII patients. The biochemical findings were in accordance with histological data, which clearly documented tissue impairment due to glycogen accumulation. Indeed, electron microscopy revealed the disruption of contractile units due to glycogen infiltrations. Furthermore, adult Agl knockout animals appeared less prompt to move, and they exhibited kyphosis. Three-mo-old Agl knockout mice could not run, and adult mice showed exercise intolerance. In addition, older affected animals exhibited an accelerated respiratory rate even at basal conditions. This observation was correlated with severe glycogen accumulation in the diaphragm. Diffuse glycogen deposition was observed in the tongues of affected mice. Our results demonstrate that this Agl knockout mouse is a reliable model for human glycogenosis type III, as it recapitulates the essential phenotypic features of the disease.
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Abstract
Disorders of glycogen metabolism are inborn errors of energy homeostasis affecting primarily skeletal muscle, heart, liver, and, less frequently, the central nervous system. These rare diseases are quite variable in age of onset, symptoms, morbidity, and mortality. This review provides an update on disorders of glycogen metabolism affecting skeletal muscle exclusively or predominantly. From a pathogenetic perspective, we classify these diseases as primary, if the defective enzyme is directly involved in glycogen/glucose metabolism, or secondary, if the genetic mutation affects proteins which indirectly regulate glycogen or glucose processing. In addition to summarizing the most recent clinical reports in this field, we briefly describe animal models of human glycogen disorders. These experimental models are greatly improving the understanding of the pathogenetic mechanisms underlying the muscle degenerative process associated to these diseases and provide in vivo platforms to test new therapeutic strategies.
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12
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Yi H, Thurberg BL, Curtis S, Austin S, Fyfe J, Koeberl DD, Kishnani PS, Sun B. Characterization of a canine model of glycogen storage disease type IIIa. Dis Model Mech 2012; 5:804-11. [PMID: 22736456 PMCID: PMC3484863 DOI: 10.1242/dmm.009712] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Glycogen storage disease type IIIa (GSD IIIa) is an autosomal recessive disease caused by deficiency of glycogen debranching enzyme (GDE) in liver and muscle. The disorder is clinically heterogeneous and progressive, and there is no effective treatment. Previously, a naturally occurring dog model for this condition was identified in curly-coated retrievers (CCR). The affected dogs carry a frame-shift mutation in the GDE gene and have no detectable GDE activity in liver and muscle. We characterized in detail the disease expression and progression in eight dogs from age 2 to 16 months. Monthly blood biochemistry revealed elevated and gradually increasing serum alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) activities; serum creatine phosphokinase (CPK) activity exceeded normal range after 12 months. Analysis of tissue biopsy specimens at 4, 12 and 16 months revealed abnormally high glycogen contents in liver and muscle of all dogs. Fasting liver glycogen content increased from 4 months to 12 months, but dropped at 16 months possibly caused by extended fibrosis; muscle glycogen content continually increased with age. Light microscopy revealed significant glycogen accumulation in hepatocytes at all ages. Liver histology showed progressive, age-related fibrosis. In muscle, scattered cytoplasmic glycogen deposits were present in most cells at 4 months, but large, lake-like accumulation developed by 12 and 16 months. Disruption of the contractile apparatus and fraying of myofibrils was observed in muscle at 12 and 16 months by electron microscopy. In conclusion, the CCR dogs are an accurate model of GSD IIIa that will improve our understanding of the disease progression and allow opportunities to investigate treatment interventions.
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Affiliation(s)
- Haiqing Yi
- Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA
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13
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Fyfe JC, Al-Tamimi RA, Liu J, Schäffer AA, Agarwala R, Henthorn PS. A novel mitofusin 2 mutation causes canine fetal-onset neuroaxonal dystrophy. Neurogenetics 2011; 12:223-32. [PMID: 21643798 PMCID: PMC3165057 DOI: 10.1007/s10048-011-0285-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 05/09/2011] [Indexed: 12/21/2022]
Abstract
We recently reported autosomal recessive fetal-onset neuroaxonal dystrophy (FNAD) in a large family of dogs that is not caused by mutation in the PLA2G6 locus (Fyfe et al., J Comp Neurol 518:3771-3784, 2010). Here, we report a genome-wide linkage analysis using 333 microsatellite markers to map canine FNAD to the telomeric end of chromosome 2. The interval of zero recombination was refined by single-nucleotide polymorphism (SNP) haplotype analysis to ~200 kb, and the included genes were sequenced. We found a homozygous 3-nucleotide deletion in exon 14 of mitofusin 2 (MFN2), predicting loss of a glutamate residue at position 539 in the protein of affected dogs. RT-PCR demonstrated near normal expression of the mutant mRNA, but MFN2 expression was undetectable to very low on western blots of affected dog brainstem, cerebrum, kidney, and cultured fibroblasts and by immunohistochemistry on brainstem sections. MFN2 is a multifunctional, membrane-bound GTPase of mitochondria and endoplasmic reticulum most commonly associated with human Charcot-Marie-Tooth disease type 2A2. The canine disorder extends the range of MFN2-associated phenotypes and suggests MFN2 as a candidate gene for rare cases of human FNAD.
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Affiliation(s)
- John C Fyfe
- Laboratory of Comparative Medical Genetics, Department of Microbiology and Molecular Genetics, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA.
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Akman HO, Raghavan A, Craigen WJ. Animal models of glycogen storage disorders. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 100:369-88. [PMID: 21377631 DOI: 10.1016/b978-0-12-384878-9.00009-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Glycogen is a polymer of glucose needed to provide for a continuous source of glucose during fasting. Glycogen synthesis and degradation are tightly controlled by complex regulatory mechanisms and any disturbance in this regulation can lead to an inadequate reservoir of glycogen or an accumulation of excess or abnormal glycogen stored either in the cytosol or in the lysosomes. Problems in the degradation or synthesis of glycogen are referred to as glycogen storage disorders (GSDs), which individually are rare diseases, yet collectively are a major category of inborn errors of metabolism in humans. To date, 11 distinct forms of GSDs are represented in animal models. These models provide a means to understand the mechanisms that regulate and execute the synthesis and degradation of glycogen. In this review, we summarize animal models that have arisen spontaneously in nature or have been engineered in the laboratory by recombinant DNA techniques, and categorize the disorders of glycogen metabolism as disorders of either synthesis or degradation.
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Affiliation(s)
- H Orhan Akman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
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Shelton GD. Routine and specialized laboratory testing for the diagnosis of neuromuscular diseases in dogs and cats. Vet Clin Pathol 2010; 39:278-95. [PMID: 20726955 DOI: 10.1111/j.1939-165x.2010.00244.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The diagnosis of neuromuscular diseases can be challenging. The first step is recognition that the disease involves the neuromuscular system (muscle, neuromuscular junction, peripheral nerve, and ventral horn cells of the spinal cord). Many neuromuscular diseases share clinical signs and cannot be distinguished based on clinical examination. Routine laboratory screening, including a CBC, biochemical profile, and urinalysis, can identify some of the most common systemic abnormalities that cause muscle weakness and myalgia, such as hypo- and hyperglycemia, electrolyte disorders, or thyroid abnormalities, and may suggest a specific diagnosis, such as diabetes mellitus, hypo- or hyperadrenocorticism, renal failure, or hypothyroidism. Increased creatine kinase activity, increased cardiac troponin I concentration, and myoglobinuria are useful in detecting skeletal and cardiac muscle damage. Identification of acetylcholine receptor antibodies is diagnostic for acquired myasthenia gravis. For primary muscle or peripheral nerve diseases, tissue biopsy is the most direct way to determine specific pathology, correctly classify the disease, and determine the course of additional laboratory testing. For example, inflammatory, necrotizing, dystrophic, metabolic, or congenital myopathies require different laboratory testing procedures for further characterization. Many neuromuscular diseases are inherited or breed-associated, and DNA-based tests may already be established or may be feasible to develop after the disorder has been accurately characterized. This review focuses on both routine and specialized laboratory testing necessary to reach a definitive diagnosis and determine an accurate prognosis for neuromuscular diseases.
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Affiliation(s)
- G Diane Shelton
- Department of Pathology, School of Medicine, University of California-San Diego, La Jolla, CA 92093, USA.
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18
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SINE indel polymorphism of AGL gene and association with growth and carcass traits in Landrace x Jeju Black pig F(2) population. Mol Biol Rep 2009; 37:467-71. [PMID: 19649726 PMCID: PMC2801833 DOI: 10.1007/s11033-009-9644-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2009] [Accepted: 07/21/2009] [Indexed: 10/31/2022]
Abstract
Genetic polymorphisms in the glycogen debrancher enzyme (AGL) gene were assessed with regard to their association with growth and carcass traits in the F(2) population crossbred Landrace and Jeju (Korea) Black pig. Three genotypes representing the insertion and/or deletion (indel) polymorphisms of short interspersed nuclear element were detected at frequencies of 0.278 (L/L), 0.479 (L/S), and 0.243 (S/S), respectively. The AGL S allele-containing pigs evidenced significantly heavier body weights at birth, the 3rd week, 10th week, and 20th week during developmental stages and higher average daily gains during the late period than were noted in the L/L homozygous pigs (P < 0.05), respectively. However, average daily gains during the early period were not significantly associated with genotype distribution (P > 0.05). With regard to the carcass traits, the S allele pigs (S/-) evidenced significantly heavier carcass weights and thicker backfat than was measured in L/L homozygous pigs (P < 0.05). However, body lengths, meat color, and marbling scores were all found not to be statistically significant (P > 0.05). Consequently, the faster growth rate during the late period and backfat deposition rather than intramuscular fat deposition cause differences in pig productivity according to genotypes of the AGL gene. These findings indicate that the AGL genotypes may prove to be useful genetic markers for the improvement of Jeju Black pig-related crossbreeding systems.
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Herszberg B, Mata X, Giulotto E, Decaunes P, Piras FM, Chowdhary BP, Chaffaux S, Guérin G. Characterization of the equine glycogen debranching enzyme gene (AGL): Genomic and cDNA structure, localization, polymorphism and expression. Gene 2007; 404:1-9. [PMID: 17905541 DOI: 10.1016/j.gene.2007.07.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Revised: 07/20/2007] [Accepted: 07/24/2007] [Indexed: 10/22/2022]
Abstract
Glycogen debranching enzyme (AGL) is a multifunctional enzyme acting in the glycogen degradation pathway. In humans, the AGL activity deficiency causes a type III glycogen storage disease (Cori-Forbes disease). One particularity of AGL gene expression lies in the multiple alternative splicing in its 5' region. The AGL gene was localized on ECA5q14-q15. The sequence of the equine cDNA was determined to be 7.5 kb in length with an open reading frame of 4602 bp. The gene is 69 kb long and contains 35 exons. The equine AGL gene has an ubiquitous expression and presents five tissue-dependent cDNA variants arising from alternative splicing of the first exons. The equine skeletal muscle and heart contain four out of six variants previously described in humans and the equine liver express three of these four human variants. We identified a new alternative splicing variant expressed in equine skeletal and heart muscles. All these mRNA variants most probably encode only two different protein isoforms of 1533 and 1377 amino-acids. Four SNPs were detected in the mRNA. The equine in silico promoter sequence reveals a structure similar to those of other mammalian species. The disposition of the transcription factor biding sites does not correlate to the transcription start sites of tissue-specific variants.
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Affiliation(s)
- Bérénice Herszberg
- Institut National de la Recherche Agronomique, UR339, Centre de Recherches de Jouy, Laboratoire de Génétique biochimique et de Cytogénétique, 78350 Jouy-en-Josas, France
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