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Arruebarrena MA, Hawe CT, Lee YM, Branco RC. Mechanisms of Cadmium Neurotoxicity. Int J Mol Sci 2023; 24:16558. [PMID: 38068881 PMCID: PMC10706630 DOI: 10.3390/ijms242316558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 11/17/2023] [Accepted: 11/18/2023] [Indexed: 12/18/2023] Open
Abstract
Cadmium is a heavy metal that increasingly contaminates food and drink products. Once ingested, cadmium exerts toxic effects that pose a significant threat to human health. The nervous system is particularly vulnerable to prolonged, low-dose cadmium exposure. This review article provides an overview of cadmium's primary mechanisms of neurotoxicity. Cadmium gains entry into the nervous system via zinc and calcium transporters, altering the homeostasis for these metal ions. Once within the nervous system, cadmium disrupts mitochondrial respiration by decreasing ATP synthesis and increasing the production of reactive oxygen species. Cadmium also impairs normal neurotransmission by increasing neurotransmitter release asynchronicity and disrupting neurotransmitter signaling proteins. Cadmium furthermore impairs the blood-brain barrier and alters the regulation of glycogen metabolism. Together, these mechanisms represent multiple sites of biochemical perturbation that result in cumulative nervous system damage which can increase the risk for neurological and neurodegenerative disorders. Understanding the way by which cadmium exerts its effects is critical for developing effective treatment and prevention strategies against cadmium-induced neurotoxic insult.
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Affiliation(s)
- Madelyn A. Arruebarrena
- Neuroscience and Behavior Program, University of Notre Dame, Notre Dame, IN 46556, USA; (M.A.A.); (Y.M.L.)
| | - Calvin T. Hawe
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA;
| | - Young Min Lee
- Neuroscience and Behavior Program, University of Notre Dame, Notre Dame, IN 46556, USA; (M.A.A.); (Y.M.L.)
| | - Rachel C. Branco
- Neuroscience and Behavior Program, University of Notre Dame, Notre Dame, IN 46556, USA; (M.A.A.); (Y.M.L.)
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA;
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2
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Onkar A, Sheshadri D, Rai A, Gupta AK, Gupta N, Ganesh S. Increase in brain glycogen levels ameliorates Huntington's disease phenotype and rescues neurodegeneration in Drosophila. Dis Model Mech 2023; 16:dmm050238. [PMID: 37681238 PMCID: PMC10602008 DOI: 10.1242/dmm.050238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 08/30/2023] [Indexed: 09/09/2023] Open
Abstract
Under normal physiological conditions, the mammalian brain contains very little glycogen, most of which is stored in astrocytes. However, the aging brain and the subareas of the brain in patients with neurodegenerative disorders tend to accumulate glycogen, the cause and significance of which remain largely unexplored. Using cellular models, we have recently demonstrated a neuroprotective role for neuronal glycogen and glycogen synthase in the context of Huntington's disease. To gain insight into the role of brain glycogen in regulating proteotoxicity, we utilized a Drosophila model of Huntington's disease, in which glycogen synthase is either knocked down or expressed ectopically. Enhancing glycogen synthesis in the brains of flies with Huntington's disease decreased mutant Huntingtin aggregation and reduced oxidative stress by activating auto-lysosomal functions. Further, overexpression of glycogen synthase in the brain rescues photoreceptor degeneration, improves locomotor deficits and increases fitness traits in this Huntington's disease model. We, thus, provide in vivo evidence for the neuroprotective functions of glycogen synthase and glycogen in neurodegenerative conditions, and their role in the neuronal autophagy process.
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Affiliation(s)
- Akanksha Onkar
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology (IIT), Kanpur 208016, India
| | - Deepashree Sheshadri
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology (IIT), Kanpur 208016, India
- Centre of Excellence in Neuroscience, Neurotechnology, and Mental Health, Gangwal School of Medical Sciences and Technology, IIT, Kanpur 208016, India
| | - Anupama Rai
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology (IIT), Kanpur 208016, India
| | - Arjit Kant Gupta
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology (IIT), Kanpur 208016, India
| | - Nitin Gupta
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology (IIT), Kanpur 208016, India
- Centre of Excellence in Neuroscience, Neurotechnology, and Mental Health, Gangwal School of Medical Sciences and Technology, IIT, Kanpur 208016, India
- The Mehta Family Centre for Engineering in Medicine, Indian Institute of Technology, Kanpur 208016, India
| | - Subramaniam Ganesh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology (IIT), Kanpur 208016, India
- Centre of Excellence in Neuroscience, Neurotechnology, and Mental Health, Gangwal School of Medical Sciences and Technology, IIT, Kanpur 208016, India
- The Mehta Family Centre for Engineering in Medicine, Indian Institute of Technology, Kanpur 208016, India
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3
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Sinha P, Verma B, Ganesh S. Age-Dependent Reduction in the Expression Levels of Genes Involved in Progressive Myoclonus Epilepsy Correlates with Increased Neuroinflammation and Seizure Susceptibility in Mouse Models. Mol Neurobiol 2022; 59:5532-5548. [PMID: 35732865 DOI: 10.1007/s12035-022-02928-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 06/14/2022] [Indexed: 11/28/2022]
Abstract
Brain aging is characterized by a gradual decline in cellular homeostatic processes, thereby losing the ability to respond to physiological stress. At the anatomical level, the aged brain is characterized by degenerating neurons, proteinaceous plaques and tangles, intracellular deposition of glycogen, and elevated neuroinflammation. Intriguingly, such age-associated changes are also seen in neurodegenerative disorders suggesting that an accelerated aging process could be one of the contributory factors for the disease phenotype. Amongst these, the genetic forms of progressive myoclonus epilepsy (PME), resulting from loss-of-function mutations in genes, manifest symptoms that are common to age-associated disorders, and genes mutated in PME are involved in the cellular homeostatic processes. Intriguingly, the incidence and/or onset of epileptic seizures are known to increase with age, suggesting that physiological changes in the aged brain might contribute to increased susceptibility to seizures. We, therefore, hypothesized that the expression level of genes implicated in PME might decrease with age, thereby leading to a compromised neuronal response towards physiological stress and hence neuroinflammation in the aging brain. Using mice models, we demonstrate here that the expression level of PME genes shows an inverse correlation with age, neuroinflammation, and compromised heat shock response. We further show that the pharmacological suppression of neuroinflammation ameliorates seizure susceptibility in aged animals as well as in animal models for a PME. Taken together, our results indicate a functional role for the PME genes in normal brain aging and that neuroinflammation could be a major contributory player in susceptibility to seizures.
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Affiliation(s)
- Priyanka Sinha
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Uttar Pradesh, Kanpur, 208016, India
| | - Bhupender Verma
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Uttar Pradesh, Kanpur, 208016, India
| | - Subramaniam Ganesh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Uttar Pradesh, Kanpur, 208016, India. .,Mehta Family Center for Engineering in Medicine, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
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4
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Napoli E, Panoutsopoulos AA, Kysar P, Satriya N, Sterling K, Shibata B, Imai D, Ruskin DN, Zarbalis KS, Giulivi C. Wdfy3 regulates glycophagy, mitophagy, and synaptic plasticity. J Cereb Blood Flow Metab 2021; 41:3213-3231. [PMID: 34187232 PMCID: PMC8669292 DOI: 10.1177/0271678x211027384] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Autophagy is essential to cell function, as it enables the recycling of intracellular constituents during starvation and in addition functions as a quality control mechanism by eliminating spent organelles and proteins that could cause cellular damage if not properly removed. Recently, we reported on Wdfy3's role in mitophagy, a clinically relevant macroautophagic scaffold protein that is linked to intellectual disability, neurodevelopmental delay, and autism spectrum disorder. In this study, we confirm our previous report that Wdfy3 haploinsufficiency in mice results in decreased mitophagy with accumulation of mitochondria with altered morphology, but expanding on that observation, we also note decreased mitochondrial localization at synaptic terminals and decreased synaptic density, which may contribute to altered synaptic plasticity. These changes are accompanied by defective elimination of glycogen particles and a shift to increased glycogen synthesis over glycogenolysis and glycophagy. This imbalance leads to an age-dependent higher incidence of brain glycogen deposits with cerebellar hypoplasia. Our results support and further extend Wdfy3's role in modulating both brain bioenergetics and synaptic plasticity by including glycogen as a target of macroautophagic degradation.
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Affiliation(s)
- Eleonora Napoli
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Alexios A Panoutsopoulos
- Department of Pathology and Laboratory Medicine, University of California, Davis, Sacramento, CA, USA.,Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA, USA
| | - Patricia Kysar
- Department of Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, CA, USA
| | - Nathaniel Satriya
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Kira Sterling
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Bradley Shibata
- Department of Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, CA, USA
| | - Denise Imai
- Anatomic Pathology Service, Veterinary Medical Teaching Hospital, University of California, Davis, CA, USA
| | - David N Ruskin
- Department of Psychology and Neuroscience Program, Trinity College, Hartford, CT, USA
| | - Konstantinos S Zarbalis
- Department of Pathology and Laboratory Medicine, University of California, Davis, Sacramento, CA, USA.,Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA, USA.,Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, CA, USA
| | - Cecilia Giulivi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA.,Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, CA, USA
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5
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Lytridou AA, Demetriadou A, Christou M, Potamiti L, Mastroyiannopoulos NP, Kyriacou K, Phylactou LA, Drousiotou A, Petrou PP. Stbd1 promotes glycogen clustering during endoplasmic reticulum stress and supports survival of mouse myoblasts. J Cell Sci 2020; 133:jcs244855. [PMID: 32958708 PMCID: PMC7648618 DOI: 10.1242/jcs.244855] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 09/16/2020] [Indexed: 01/08/2023] Open
Abstract
Imbalances in endoplasmic reticulum (ER) homeostasis provoke a condition known as ER stress and activate the unfolded protein response (UPR) pathway, an evolutionarily conserved cell survival mechanism. Here, we show that mouse myoblasts respond to UPR activation by stimulating glycogenesis and the formation of α-amylase-degradable, glycogen-containing ER structures. We demonstrate that the glycogen-binding protein Stbd1 is markedly upregulated through the PERK signalling branch of the UPR pathway and is required for the build-up of glycogen structures in response to ER stress activation. In the absence of ER stress, Stbd1 overexpression is sufficient to induce glycogen clustering but does not stimulate glycogenesis. Glycogen structures induced by ER stress are degraded under conditions of glucose restriction through a process that does not depend on autophagosome-lysosome fusion. Furthermore, we provide evidence that failure to induce glycogen clustering during ER stress is associated with enhanced activation of the apoptotic pathway. Our results reveal a so far unknown response of mouse myoblasts to ER stress and uncover a novel specific function of Stbd1 in this process, which may have physiological implications during myogenic differentiation.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Andria A Lytridou
- Department of Biochemical Genetics, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus
| | - Anthi Demetriadou
- Department of Biochemical Genetics, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus
| | - Melina Christou
- Department of Molecular Genetics, Function and Therapy, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus
| | - Louiza Potamiti
- Department of Electron Microscopy/Molecular Pathology, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
| | - Nikolas P Mastroyiannopoulos
- Department of Molecular Genetics, Function and Therapy, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus
| | - Kyriacos Kyriacou
- Department of Electron Microscopy/Molecular Pathology, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus
| | - Leonidas A Phylactou
- Department of Molecular Genetics, Function and Therapy, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus
| | - Anthi Drousiotou
- Department of Biochemical Genetics, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus
| | - Petros P Petrou
- Department of Biochemical Genetics, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus
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6
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Sullivan MA, Nitschke S, Skwara EP, Wang P, Zhao X, Pan XS, Chown EE, Wang T, Perri AM, Lee JPY, Vilaplana F, Minassian BA, Nitschke F. Skeletal Muscle Glycogen Chain Length Correlates with Insolubility in Mouse Models of Polyglucosan-Associated Neurodegenerative Diseases. Cell Rep 2020; 27:1334-1344.e6. [PMID: 31042462 DOI: 10.1016/j.celrep.2019.04.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 01/29/2019] [Accepted: 04/02/2019] [Indexed: 01/31/2023] Open
Abstract
Lafora disease (LD) and adult polyglucosan body disease (APBD) are glycogen storage diseases characterized by a pathogenic buildup of insoluble glycogen. Mechanisms causing glycogen insolubility are poorly understood. Here, in two mouse models of LD (Epm2a-/- and Epm2b-/-) and one of APBD (Gbe1ys/ys), the separation of soluble and insoluble muscle glycogen is described, enabling separate analysis of each fraction. Total glycogen is increased in LD and APBD mice, which, together with abnormal chain length and molecule size distributions, is largely if not fully attributed to insoluble glycogen. Soluble glycogen consists of molecules with distinct chain length distributions and differential corresponding solubility, providing a mechanistic link between soluble and insoluble glycogen in vivo. Phosphorylation states differ across glycogen fractions and mouse models, demonstrating that hyperphosphorylation is not a basic feature of insoluble glycogen. Lastly, model-specific variances in protein and activity levels of key glycogen synthesis enzymes suggest uninvestigated regulatory mechanisms.
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Affiliation(s)
- Mitchell A Sullivan
- Program in Genetics and Genome Biology, Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada; Glycation and Diabetes, Translational Research Institute, Mater Research Institute - University of Queensland, Brisbane, QLD 4102, Australia
| | - Silvia Nitschke
- Program in Genetics and Genome Biology, Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada
| | - Evan P Skwara
- Program in Genetics and Genome Biology, Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada
| | - Peixiang Wang
- Program in Genetics and Genome Biology, Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada
| | - Xiaochu Zhao
- Program in Genetics and Genome Biology, Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada
| | - Xiao S Pan
- Program in Genetics and Genome Biology, Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada; Institute of Medical Science, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Erin E Chown
- Program in Genetics and Genome Biology, Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada; Institute of Medical Science, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Travis Wang
- Program in Genetics and Genome Biology, Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada
| | - Ami M Perri
- Program in Genetics and Genome Biology, Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada
| | - Jennifer P Y Lee
- Program in Genetics and Genome Biology, Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada
| | - Francisco Vilaplana
- Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, AlbaNova University Centre, Stockholm 10691, Sweden
| | - Berge A Minassian
- Program in Genetics and Genome Biology, Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada; Institute of Medical Science, University of Toronto, Toronto, ON M5S 1A8, Canada; Division of Neurology, Department of Pediatrics, University of Texas Southwestern, Dallas, TX 75390, USA
| | - Felix Nitschke
- Program in Genetics and Genome Biology, Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada.
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7
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Li C, Wei Q, Gu X, Chen Y, Chen X, Cao B, Ou R, Shang H. Decreased Glycogenolysis by miR-338-3p Promotes Regional Glycogen Accumulation Within the Spinal Cord of Amyotrophic Lateral Sclerosis Mice. Front Mol Neurosci 2019; 12:114. [PMID: 31133799 PMCID: PMC6514045 DOI: 10.3389/fnmol.2019.00114] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 04/18/2019] [Indexed: 02/05/2023] Open
Abstract
Metabolic dysfunction is a hallmark of age-related neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). But the crosstalk between metabolic alteration and disease progression in ALS is still largely unknown. Glycogen, a branched polymer of glucose residues, is universally recognized as the energy reserve of the central nervous system (CNS), where its aberrant accumulation instigates neurodegeneration. Glycogen was reported to be accumulated in both CNS and visceral organs of SOD1G93A mice, a well-known ALS model, and contributes to the pathological process of ALS. However, the accumulative patterns and mechanisms are not well elucidated. Here, we provide extensive evidence to demonstrate that glycogen accumulated in the lumbar spinal cord of ALS mice along with the disease progression, but not in the motor cortex. This regional accumulation of glycogen was caused by deteriorated glycogenolysis, which was triggered by decreased glycogen phosphorylase, brain form (PYGB). Moreover, miR-338-3p, an elevated miRNA in the spinal cord of SOD1G93A mice, directly targeted PYGB and was responsible for the decreased glycogenolysis and subsequent glycogen accumulation. Our work is helpful for better understanding of of of metabolic dysfunctions in ALS and provides novel targets for the therapeutic intervention in the future.
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Affiliation(s)
- Chunyu Li
- Department of Neurology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Qianqian Wei
- Department of Neurology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaojing Gu
- Department of Neurology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Yongping Chen
- Department of Neurology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Xueping Chen
- Department of Neurology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Bei Cao
- Department of Neurology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Ruwei Ou
- Department of Neurology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Huifang Shang
- Department of Neurology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
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8
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9
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Parihar R, Rai A, Ganesh S. Lafora disease: from genotype to phenotype. J Genet 2018; 97:611-624. [PMID: 30027899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The progressive myoclonic epilepsy of Lafora or Lafora disease (LD) is a neurodegenerative disorder characterized by recurrent seizures and cognitive deficits. With typical onset in the late childhood or early adolescence, the patients show progressive worsening of the disease symptoms, leading to death in about 10 years. It is an autosomal recessive disorder caused by the loss-of-function mutations in the EPM2A gene, coding for a protein phosphatase (laforin) or the NHLRC1 gene coding for an E3 ubiquitin ligase (malin). LD is characterized by the presence of abnormally branched water insoluble glycogen inclusions known as Lafora bodies in the neurons and other tissues, suggesting a role for laforin and malin in glycogen metabolic pathways. Mouse models of LD, developed by targeted disruption of the Epm2a or Nhlrc1 gene, recapitulated most of the symptoms and pathological features as seen in humans, and have offered insight into the pathomechanisms. Besides the formation of Lafora bodies in the neurons in the presymptomatic stage, the animal models have also demonstrated perturbations in the proteolytic pathways, such as ubiquitin proteasome system and autophagy, and inflammatory response. This review attempts to provide a comprehensive coverage on the genetic defects leading to the LD in humans, on the functional properties of the laforin and malin proteins, and on how defects in any one of these two proteins result in a clinically similar phenotype. We also discuss the disease pathologies as revealed by the studies on the animal models and, finally, on the progress with therapeutic attempts albeit in the animal models.
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Affiliation(s)
- Rashmi Parihar
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208 016, India.
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10
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Rai A, Singh PK, Singh V, Kumar V, Mishra R, Thakur AK, Mahadevan A, Shankar SK, Jana NR, Ganesh S. Glycogen synthase protects neurons from cytotoxicity of mutant huntingtin by enhancing the autophagy flux. Cell Death Dis 2018; 9:201. [PMID: 29422655 PMCID: PMC5833817 DOI: 10.1038/s41419-017-0190-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/22/2017] [Accepted: 11/24/2017] [Indexed: 12/11/2022]
Abstract
Healthy neurons do not store glycogen while they do possess the machinery for the glycogen synthesis albeit at an inactive state. Neurons in the degenerating brain, however, are known to accumulate glycogen, although its significance was not well understood. Emerging reports present contrasting views on neuronal glycogen synthesis; a few reports demonstrate a neurotoxic effect of glycogen while a few others suggest glycogen to be neuroprotective. Thus, the specific role of glycogen and glycogen synthase in neuronal physiology is largely unexplored. Using cellular and animal models of Huntington's disease, we show here that the overexpression of cytotoxic mutant huntingtin protein induces glycogen synthesis in the neurons by activating glycogen synthase and the overexpressed glycogen synthase protected neurons from the cytotoxicity of the mutant huntingtin. Exposure of neuronal cells to proteasomal blockade and oxidative stress also activate glycogen synthase to induce glycogen synthesis and to protect against stress-induced neuronal death. We show that the glycogen synthase plays an essential and inductive role in the neuronal autophagic flux, and helps in clearing the cytotoxic huntingtin aggregate. We also show that the increased neuronal glycogen inhibits the aggregation of mutant huntingtin, and thus could directly contribute to its clearance. Finally, we demonstrate that excessive autophagy flux is the molecular basis of cell death caused by the activation of glycogen synthase in unstressed neurons. Taken together, our results thus provide a novel function for glycogen synthase in proteolytic processes and offer insight into the role of glycogen synthase and glycogen in both survival and death of the neurons.
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Affiliation(s)
- Anupama Rai
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, 208016, India
| | - Pankaj Kumar Singh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, 208016, India
- Institut de Génétique et de Biologie Moléculaire et Cellulare (IGBMC), Illkirch, France
| | - Virender Singh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, 208016, India
| | | | - Rohit Mishra
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, 208016, India
| | - Ashwani Kumar Thakur
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, 208016, India
| | - Anita Mahadevan
- Department of Neuropathology, National Institute of Mental Health and Neuroscience, Bengaluru, 560029, India
| | - Susarla Krishna Shankar
- Department of Neuropathology, National Institute of Mental Health and Neuroscience, Bengaluru, 560029, India
| | | | - Subramaniam Ganesh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, 208016, India.
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11
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Kakhlon O. Pharmacological approaches for treating glycogen storage disorders involving polyglucosan body accumulation. Expert Opin Orphan Drugs 2017. [DOI: 10.1080/21678707.2017.1405804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Or Kakhlon
- Department of Neurology, Hadassah Medical Association, Ein Kerem, Jerusalem, Israel
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12
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A novel image-based high-throughput screening assay discovers therapeutic candidates for adult polyglucosan body disease. Biochem J 2017; 474:3403-3420. [PMID: 28827282 DOI: 10.1042/bcj20170469] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Revised: 07/20/2017] [Accepted: 08/17/2017] [Indexed: 01/26/2023]
Abstract
Glycogen storage disorders (GSDs) are caused by excessive accumulation of glycogen. Some GSDs [adult polyglucosan (PG) body disease (APBD), and Tarui and Lafora diseases] are caused by intracellular accumulation of insoluble inclusions, called PG bodies (PBs), which are chiefly composed of malconstructed glycogen. We developed an APBD patient skin fibroblast cell-based assay for PB identification, where the bodies are identified as amylase-resistant periodic acid-Schiff's-stained structures, and quantified. We screened the DIVERSet CL 10 084 compound library using this assay in high-throughput format and discovered 11 dose-dependent and 8 non-dose-dependent PB-reducing hits. Approximately 70% of the hits appear to act through reducing glycogen synthase (GS) activity, which can elongate glycogen chains and presumably promote PB generation. Some of these GS inhibiting hits were also computationally predicted to be similar to drugs interacting with the GS activator protein phosphatase 1. Our work paves the way to discovering medications for the treatment of PB-involving GSD, which are extremely severe or fatal disorders.
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13
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Alvarez R, Casas J, López DJ, Ibarguren M, Suari-Rivera A, Terés S, Guardiola-Serrano F, Lossos A, Busquets X, Kakhlon O, Escribá PV. Triacylglycerol mimetics regulate membrane interactions of glycogen branching enzyme: implications for therapy. J Lipid Res 2017. [PMID: 28630259 DOI: 10.1194/jlr.m075531] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Adult polyglucosan body disease (APBD) is a neurological disorder characterized by adult-onset neurogenic bladder, spasticity, weakness, and sensory loss. The disease is caused by aberrant glycogen branching enzyme (GBE) (GBE1Y329S) yielding less branched, globular, and soluble glycogen, which tends to aggregate. We explore here whether, despite being a soluble enzyme, GBE1 activity is regulated by protein-membrane interactions. Because soluble proteins can contact a wide variety of cell membranes, we investigated the interactions of purified WT and GBE1Y329S proteins with different types of model membranes (liposomes). Interestingly, both triheptanoin and some triacylglycerol mimetics (TGMs) we have designed (TGM0 and TGM5) markedly enhance GBE1Y329S activity, possibly enough for reversing APBD symptoms. We show that the GBE1Y329S mutation exposes a hydrophobic amino acid stretch, which can either stabilize and enhance or alternatively, reduce the enzyme activity via alteration of protein-membrane interactions. Additionally, we found that WT, but not Y329S, GBE1 activity is modulated by Ca2+ and phosphatidylserine, probably associated with GBE1-mediated regulation of energy consumption and storage. The thermal stabilization and increase in GBE1Y329S activity induced by TGM5 and its omega-3 oil structure suggest that this molecule has a considerable therapeutic potential for treating APBD.
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Affiliation(s)
- Rafael Alvarez
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Jesús Casas
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - David J López
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Maitane Ibarguren
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Ariadna Suari-Rivera
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Silvia Terés
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Francisca Guardiola-Serrano
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Alexander Lossos
- Department of Neurology, Hadassah-Hebrew University Medical Center, E-91120 Jerusalem, Israel
| | - Xavier Busquets
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Or Kakhlon
- Department of Neurology, Hadassah-Hebrew University Medical Center, E-91120 Jerusalem, Israel.
| | - Pablo V Escribá
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain.
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14
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DiNuzzo M, Mangia S, Maraviglia B, Giove F. Does abnormal glycogen structure contribute to increased susceptibility to seizures in epilepsy? Metab Brain Dis 2015; 30:307-16. [PMID: 24643875 PMCID: PMC4169361 DOI: 10.1007/s11011-014-9524-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 03/05/2014] [Indexed: 12/22/2022]
Abstract
Epilepsy is a family of brain disorders with a largely unknown etiology and high percentage of pharmacoresistance. The clinical manifestations of epilepsy are seizures, which originate from aberrant neuronal synchronization and hyperexcitability. Reactive astrocytosis, a hallmark of the epileptic tissue, develops into loss-of-function of glutamine synthetase, impairment of glutamate-glutamine cycle and increase in extracellular and astrocytic glutamate concentration. Here, we argue that chronically elevated intracellular glutamate level in astrocytes is instrumental to alterations in the metabolism of glycogen and leads to the synthesis of polyglucosans. Unaccessibility of glycogen-degrading enzymes to these insoluble molecules compromises the glycogenolysis-dependent reuptake of extracellular K(+) by astrocytes, thereby leading to increased extracellular K(+) and associated membrane depolarization. Based on current knowledge, we propose that the deterioration in structural homogeneity of glycogen particles is relevant to disruption of brain K(+) homeostasis and increased susceptibility to seizures in epilepsy.
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Affiliation(s)
- Mauro DiNuzzo
- MARBILab, Museo storico della fisica e Centro di studi e ricerche "Enrico Fermi", Rome, Italy,
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15
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Singh PK, Singh S, Ganesh S. Activation of serum/glucocorticoid-induced kinase 1 (SGK1) underlies increased glycogen levels, mTOR activation, and autophagy defects in Lafora disease. Mol Biol Cell 2013; 24:3776-86. [PMID: 24131995 PMCID: PMC3861076 DOI: 10.1091/mbc.e13-05-0261] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Lafora disease (LD), a fatal genetic form of myoclonic epilepsy, is characterized by abnormally high levels of cellular glycogen and its accumulation as Lafora bodies in affected tissues. Therefore the two defective proteins in LD-laforin phosphatase and malin ubiquitin ligase-are believed to be involved in glycogen metabolism. We earlier demonstrated that laforin and malin negatively regulate cellular glucose uptake by preventing plasma membrane targeting of glucose transporters. We show here that loss of laforin results in activation of serum/glucocorticoid-induced kinase 1 (SGK1) in cellular and animals models and that inhibition of SGK1 in laforin-deficient cells reduces the level of plasma membrane-bound glucose transporter, glucose uptake, and the consequent glycogen accumulation. We also provide evidence to suggest that mammalian target of rapamycin (mTOR) activates SGK1 kinase in laforin-deficient cells. The mTOR activation appears to be a glucose-dependent event, and overexpression of dominant-negative SGK1 suppresses mTOR activation, suggesting the existence of a feedforward loop between SGK1 and mTOR. Our findings indicate that inhibition of SGK1 activity could be an effective therapeutic approach to suppress glycogen accumulation, inhibit mTOR activity, and rescue autophagy defects in LD.
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Affiliation(s)
- Pankaj Kumar Singh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
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16
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Laforin-malin complex degrades polyglucosan bodies in concert with glycogen debranching enzyme and brain isoform glycogen phosphorylase. Mol Neurobiol 2013; 49:645-57. [PMID: 24068615 DOI: 10.1007/s12035-013-8546-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 08/27/2013] [Indexed: 10/26/2022]
Abstract
In Lafora disease (LD), the deficiency of either EPM2A or NHLRC1, the genes encoding the phosphatase laforin and E3 ligase, respectively, causes massive accumulation of less-branched glycogen inclusions, known as Lafora bodies, also called polyglucosan bodies (PBs), in several types of cells including neurons. The biochemical mechanism underlying the PB accumulation, however, remains undefined. We recently demonstrated that laforin is a phosphatase of muscle glycogen synthase (GS1) in PBs, and that laforin recruits malin, together reducing PBs. We show here that accomplishment of PB degradation requires a protein assembly consisting of at least four key enzymes: laforin and malin in a complex, and the glycogenolytic enzymes, glycogen debranching enzyme 1 (AGL1) and brain isoform glycogen phosphorylase (GPBB). Once GS1-synthesized polyglucosan accumulates into PBs, laforin recruits malin to the PBs where laforin dephosphorylates, and malin degrades the GS1 in concert with GPBB and AGL1, resulting in a breakdown of polyglucosan. Without fountional laforin-malin complex assembled on PBs, GPBB and AGL1 together are unable to efficiently breakdown polyglucosan. All these events take place on PBs and in cytoplasm. Deficiency of each of the four enzymes causes PB accumulation in the cytoplasm of affected cells. Demonstration of the molecular mechanisms underlying PB degradation lays a substantial biochemical foundation that may lead to understanding how PB metabolizes and why mutations of either EPM2A or NHLRC1 in humans cause LD. Mutations in AGL1 or GPBB may cause diseases related to PB accumulation.
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17
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Kakhlon O, Glickstein H, Feinstein N, Liu Y, Baba O, Terashima T, Akman HO, Dimauro S, Lossos A. Polyglucosan neurotoxicity caused by glycogen branching enzyme deficiency can be reversed by inhibition of glycogen synthase. J Neurochem 2013; 127:101-13. [PMID: 23607684 DOI: 10.1111/jnc.12277] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 04/10/2013] [Accepted: 04/18/2013] [Indexed: 12/25/2022]
Abstract
Uncontrolled elongation of glycogen chains, not adequately balanced by their branching, leads to the formation of an insoluble, presumably neurotoxic, form of glycogen called polyglucosan. To test the suspected pathogenicity of polyglucosans in neurological glycogenoses, we have modeled the typical glycogenosis Adult Polyglucosan Body Disease (APBD) by suppressing glycogen branching enzyme 1 (GBE1, EC 2.4.1.18) expression using lentiviruses harboring short hairpin RNA (shRNA). GBE1 suppression in embryonic cortical neurons led to polyglucosan accumulation and associated apoptosis, which were reversible by rapamycin or starvation treatments. Further analysis revealed that rapamycin and starvation led to phosphorylation and inactivation of glycogen synthase (GS, EC 2.4.1.11), dephosphorylated and activated in the GBE1-suppressed neurons. These protective effects of rapamycin and starvation were reversed by overexpression of phosphorylation site mutant GS only if its glycogen binding site was intact. While rapamycin and starvation induce autophagy, autophagic maturation was not required for their corrective effects, which prevailed even if autophagic flux was inhibited by vinblastine. Furthermore, polyglucosans were not observed in any compartment along the autophagic pathway. Our data suggest that glycogen branching enzyme repression in glycogenoses can cause pathogenic polyglucosan buildup, which might be corrected by GS inhibition.
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Affiliation(s)
- Or Kakhlon
- Department of Neurology, Hadassah-Hebrew University Medical Center, Ein Kerem, Jerusalem, Israel
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