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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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2
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Shahal T, Segev E, Konstantinovsky T, Marcus Y, Shefer G, Pasmanik-Chor M, Buch A, Ebenstein Y, Zimmet P, Stern N. Deconvolution of the epigenetic age discloses distinct inter-personal variability in epigenetic aging patterns. Epigenetics Chromatin 2022; 15:9. [PMID: 35255955 PMCID: PMC8900303 DOI: 10.1186/s13072-022-00441-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 02/21/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The epigenetic age can now be extrapolated from one of several epigenetic clocks, which are based on age-related changes in DNA methylation levels at specific multiple CpG sites. Accelerated aging, calculated from the discrepancy between the chronological age and the epigenetic age, has shown to predict morbidity and mortality rate. We assumed that deconvolution of epigenetic age to its components could shed light on the diversity of epigenetic, and by inference, on inter-individual variability in the causes of biological aging. RESULTS Using the Horvath original epigenetic clock, we identified several CpG sites linked to distinct genes that quantitatively explain much of the inter-personal variability in epigenetic aging, with CpG sites related to secretagogin and malin being the most variable. We show that equal epigenetic age in different subjects can result from variable contribution size of the same CpG sites to the total epigenetic age. In a healthy cohort, the most variable CpG sites are responsible for accelerated and decelerated epigenetic aging, relative to chronological age. CONCLUSIONS Of the 353 CpG sites that form the basis for the Horvath epigenetic age, we have found the CpG sites that are responsible for accelerated and decelerated epigenetic aging in healthy subjects. However, the relative contribution of each site to aging varies between individuals, leading to variable personal aging patterns. Our findings pave the way to form personalized aging cards allowing the identification of specific genes related to CpG sites, as aging markers, and perhaps treatment of these targets in order to hinder undesirable age drifting.
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Affiliation(s)
- Tamar Shahal
- The Sagol Center for Epigenetics of Aging and Metabolism, Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Department of Chemistry, Tel Aviv University, Tel Aviv, Israel
| | - Elad Segev
- Department of Applied Mathematics, Holon Institute of Technology, Holon, Israel
| | - Thomas Konstantinovsky
- The Sagol Center for Epigenetics of Aging and Metabolism, Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Department of Applied Mathematics, Holon Institute of Technology, Holon, Israel
| | - Yonit Marcus
- The Sagol Center for Epigenetics of Aging and Metabolism, Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,The Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Gabi Shefer
- The Sagol Center for Epigenetics of Aging and Metabolism, Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Metsada Pasmanik-Chor
- Bioinformatics Unit, The George S. Wise Faculty of Life Science, Tel Aviv University, Tel Aviv, Israel
| | - Assaf Buch
- The Sagol Center for Epigenetics of Aging and Metabolism, Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yuval Ebenstein
- Department of Chemistry, Tel Aviv University, Tel Aviv, Israel
| | - Paul Zimmet
- Department of Diabetes, Monash University School of Medicine, Melbourne, Australia
| | - Naftali Stern
- The Sagol Center for Epigenetics of Aging and Metabolism, Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv-Sourasky Medical Center; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. .,The Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel.
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3
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Chatterjee M, Sengupta S. Human Satellite III long non-coding RNA imparts survival benefits to cancer cells. Cell Biol Int 2022; 46:611-627. [PMID: 35005799 DOI: 10.1002/cbin.11761] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 11/06/2021] [Accepted: 12/26/2021] [Indexed: 11/07/2022]
Abstract
Long non-coding RNAs (lncRNAs) are heterogeneous group of transcripts that lack coding potential and have essential roles in gene regulations. Recent days have seen an increasing association of non-coding RNAs with human diseases, especially cancers. One interesting group of non-coding RNAs strongly linked to cancers are heterochromatic repetitive Satellite RNAs. Satellite RNAs are transcribed from pericentromeric heterochromatic region of the human chromosomes. Satellite II RNA, most extensively studied, is upregulated in wide variety of epithelial cancer. Similarly, alpha satellite is over expressed in BRCA1- deficient tumors. Though much is known about alpha satellites and SatII repeats, little is known about Satellite III (SatIII) lncRNAs in human cancers. SatIII repeats, though transcriptionally silent in normal conditions is actively transcribed under condition of stress, mainly heat shock. In the present study, we show that colon and breast cancer cells aberrantly transcribes SatIII, in a Heat shock factor I (HSF1)-independent manner. Our study also reveals that, overexpression of SatIII RNA favours cancer cell survival by overriding chemo drug-induced cell death. Interestingly, knockdown of SatIII sensitizes cells towards chemotherapeutic drugs. This sensitization is possibly mediated by restoration of p53 protein expression that facilitates cell death. Heat shock however helps SatIII to continue with its pro-cell survival function. Our results, therefore suggest SatIII to be an important regulator of human cancers. Induction of SatIII is not only a response to the oncogenic stress but also facilitates cancer progression by a distinct pathway that is different from heat stress pathway. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Manjima Chatterjee
- School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, India
| | - Sonali Sengupta
- School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, India
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4
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TRIM32 and Malin in Neurological and Neuromuscular Rare Diseases. Cells 2021; 10:cells10040820. [PMID: 33917450 PMCID: PMC8067510 DOI: 10.3390/cells10040820] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/01/2021] [Accepted: 04/04/2021] [Indexed: 12/27/2022] Open
Abstract
Tripartite motif (TRIM) proteins are RING E3 ubiquitin ligases defined by a shared domain structure. Several of them are implicated in rare genetic diseases, and mutations in TRIM32 and TRIM-like malin are associated with Limb-Girdle Muscular Dystrophy R8 and Lafora disease, respectively. These two proteins are evolutionary related, share a common ancestor, and both display NHL repeats at their C-terminus. Here, we revmniew the function of these two related E3 ubiquitin ligases discussing their intrinsic and possible common pathophysiological pathways.
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Sinha P, Verma B, Ganesh S. Trehalose Ameliorates Seizure Susceptibility in Lafora Disease Mouse Models by Suppressing Neuroinflammation and Endoplasmic Reticulum Stress. Mol Neurobiol 2021; 58:1088-1101. [PMID: 33094475 DOI: 10.1007/s12035-020-02170-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 10/14/2020] [Indexed: 12/20/2022]
Abstract
Lafora disease (LD) is one of the progressive and fatal forms of a neurodegenerative disorder and is characterized by teenage-onset myoclonic seizures. Neuropathological changes in LD include the formation of abnormal glycogen as Lafora bodies, gliosis, and neuroinflammation. LD is caused by defects in the gene coding for phosphatase (laforin) or ubiquitin ligase (malin). Mouse models of LD, developed by targeted disruption of these two genes, develop most symptoms of LD and show increased susceptibility to induced seizures. Studies on mouse models also suggest that defective autophagy might contribute to LD etiology. In an attempt to understand the specific role of autophagy in LD pathogenesis, in this study, we fed LD animals with trehalose, an inducer of autophagy, for 3 months and looked at its effect on the neuropathology and seizure susceptibility. We demonstrate here that trehalose ameliorates gliosis, neuroinflammation, and endoplasmic reticulum stress and reduces susceptibility to induced seizures in LD animals. However, trehalose did not affect the formation of Lafora bodies, suggesting the epileptic phenotype in LD could be either secondary to or independent of Lafora bodies. Taken together, our results suggest that autophagy inducers can be considered as potential therapeutic molecules for Lafora disease.
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Affiliation(s)
- Priyanka Sinha
- Department of Biological Sciences & Bioengineering, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Bhupender Verma
- Department of Biological Sciences & Bioengineering, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Subramaniam Ganesh
- Department of Biological Sciences & Bioengineering, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
- The Mehta Family Centre for Engineering in Medicine, Indian Institute of Technology Kanpur, Kanpur, India.
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6
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Sinha P, Verma B, Ganesh S. Dexamethasone-induced activation of heat shock response ameliorates seizure susceptibility and neuroinflammation in mouse models of Lafora disease. Exp Neurol 2021; 340:113656. [PMID: 33639210 DOI: 10.1016/j.expneurol.2021.113656] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 01/26/2021] [Accepted: 02/21/2021] [Indexed: 11/29/2022]
Abstract
Heat shock response (HSR) is a conserved cytoprotective pathway controlled by the master transcriptional regulator, the heat shock factor 1 (HSF1), that activates the expression of heat shock proteins (HSPs). HSPs, as chaperones, play essential roles in minimizing stress-induced damages and restoring proteostasis. Therefore, compromised HSR is thought to contribute to neurodegenerative disorders. Lafora disease (LD) is a fatal form of neurodegenerative disorder characterized by the accumulation of abnormal glycogen as Lafora bodies in neurons and other tissues. The symptoms of LD include progressive myoclonus epilepsy, dementia, and cognitive deficits. LD is caused by the defects in the gene coding laforin phosphatase or the malin ubiquitin ligase. Laforin and malin are known to work upstream of HSF1 and are essential for the activation of HSR. Herein, we show that mice deficient for laforin or malin show reduced levels of HSF1 and their targets in their brain tissues, suggesting compromised HSR; this could contribute to the neuropathology in LD. Intriguingly, treatment of LD animals with dexamethasone, a synthetic glucocorticoid analogue, partially restored the levels of HSF1 and its targets. Dexamethasone treatment was also able to ameliorate the neuroinflammation and susceptibility to induced seizures in the LD animals. However, dexamethasone treatment did not show a significant effect on Lafora bodies or autophagy defects. Taken together, the present study establishes a role for HSR in seizure susceptibility and neuroinflammation and dexamethasone as a potential antiepileptic agent, suitable for further studies in LD.
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Affiliation(s)
- Priyanka Sinha
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
| | - Bhupender Verma
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
| | - Subramaniam Ganesh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India.
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7
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Taneja K, Ganesh S. Dendritic spine abnormalities correlate with behavioral and cognitive deficits in mouse models of Lafora disease. J Comp Neurol 2020; 529:1099-1120. [DOI: 10.1002/cne.25006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 06/20/2020] [Accepted: 08/04/2020] [Indexed: 01/03/2023]
Affiliation(s)
- Komal Taneja
- Department of Biological Sciences and Bioengineering Indian Institute of Technology Kanpur Kanpur Uttar Pradesh India
| | - Subramaniam Ganesh
- Department of Biological Sciences and Bioengineering Indian Institute of Technology Kanpur Kanpur Uttar Pradesh India
- The Mehta Family Centre for Engineering in Medicine Indian Institute of Technology Kanpur Kanpur Uttar Pradesh India
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8
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Bhat S, Ganesh S. New discoveries in progressive myoclonus epilepsies: a clinical outlook. Expert Rev Neurother 2018; 18:649-667. [DOI: 10.1080/14737175.2018.1503949] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Shweta Bhat
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
| | - Subramaniam Ganesh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
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9
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Lafora Disease: A Ubiquitination-Related Pathology. Cells 2018; 7:cells7080087. [PMID: 30050012 PMCID: PMC6116066 DOI: 10.3390/cells7080087] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 07/23/2018] [Accepted: 07/24/2018] [Indexed: 11/17/2022] Open
Abstract
Lafora disease (LD, OMIM254780) is a rare and fatal form of progressive myoclonus epilepsy (PME). Among PMEs, LD is unique because of the rapid neurological deterioration of the patients and the appearance in brain and peripheral tissues of insoluble glycogen-like (polyglucosan) inclusions, named Lafora bodies (LBs). LD is caused by mutations in the EPM2A gene, encoding the dual phosphatase laforin, or the EPM2B gene, encoding the E3-ubiquitin ligase malin. Laforin and malin form a functional complex that is involved in the regulation of glycogen synthesis. Thus, in the absence of a functional complex glycogen accumulates in LBs. In addition, it has been suggested that the laforin-malin complex participates in alternative physiological pathways, such as intracellular protein degradation, oxidative stress, and the endoplasmic reticulum unfolded protein response. In this work we review the possible cellular functions of laforin and malin with a special focus on their role in the ubiquitination of specific substrates. We also discuss here the pathological consequences of defects in laforin or malin functions, as well as the therapeutic strategies that are being explored for LD.
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11
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Upadhyay M, Agarwal S, Bhadauriya P, Ganesh S. Loss of laforin or malin results in increased Drp1 level and concomitant mitochondrial fragmentation in Lafora disease mouse models. Neurobiol Dis 2017; 100:39-51. [DOI: 10.1016/j.nbd.2017.01.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 12/24/2016] [Accepted: 01/03/2017] [Indexed: 02/02/2023] Open
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12
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Jain N, Rai A, Mishra R, Ganesh S. Loss of malin, but not laforin, results in compromised autophagic flux and proteasomal dysfunction in cells exposed to heat shock. Cell Stress Chaperones 2017; 22:307-315. [PMID: 27975203 PMCID: PMC5352594 DOI: 10.1007/s12192-016-0754-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 12/04/2016] [Accepted: 12/05/2016] [Indexed: 11/29/2022] Open
Abstract
Heat stress to a cell leads to the activation of heat shock response, which is required for the management of misfolded and unfolded proteins. Macroautophagy and proteasome-mediated degradation are the two cellular processes that degrade polyubiquitinated, misfolded proteins. Contrasting pieces of evidence exist on the effect of heat stress on the activation of the above-mentioned degradative pathways. Laforin phosphatase and malin E3 ubiquitin ligase, the two proteins defective in Lafora neurodegenerative disorder, are involved in cellular stress response pathways and are required for the activation of heat shock transcription factor - the heat shock factor 1 (HSF1) - and, consequently, for cellular protection under heat shock. While the role of laforin and malin in the proteolytic pathways is well established, their role in cellular recovery from heat shock was not explored. To address this, we investigated autophagic flux, proteasomal activity, and the level of polyubiquitinated proteins in Neuro2a cells partially silenced for laforin or malin protein and exposed to heat shock. We found that heat shock was able to induce autophagic flux, proteasomal activity and reduce the polyubiquitinated proteins load in the laforin-silenced cells but not in the malin-deficient cells. Loss of malin leads to reduced proteasomal activity in the heat-shocked cells. Taken together, our results suggest a distinct mode of action for laforin and malin in the heat shock-induced proteolytic processes.
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Affiliation(s)
- Navodita Jain
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, 208016, India
| | - Anupama Rai
- 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
| | - Subramaniam Ganesh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, 208016, India.
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Joshi V, Amanullah A, Upadhyay A, Mishra R, Kumar A, Mishra A. A Decade of Boon or Burden: What Has the CHIP Ever Done for Cellular Protein Quality Control Mechanism Implicated in Neurodegeneration and Aging? Front Mol Neurosci 2016; 9:93. [PMID: 27757073 PMCID: PMC5047891 DOI: 10.3389/fnmol.2016.00093] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 09/20/2016] [Indexed: 01/13/2023] Open
Abstract
Cells regularly synthesize new proteins to replace old and abnormal proteins for normal cellular functions. Two significant protein quality control pathways inside the cellular milieu are ubiquitin proteasome system (UPS) and autophagy. Autophagy is known for bulk clearance of cytoplasmic aggregated proteins, whereas the specificity of protein degradation by UPS comes from E3 ubiquitin ligases. Few E3 ubiquitin ligases, like C-terminus of Hsc70-interacting protein (CHIP) not only take part in protein quality control pathways, but also plays a key regulatory role in other cellular processes like signaling, development, DNA damage repair, immunity and aging. CHIP targets misfolded proteins for their degradation through proteasome, as well as autophagy; simultaneously, with the help of chaperones, it also regulates folding attempts for misfolded proteins. The broad range of CHIP substrates and their associations with multiple pathologies make it a key molecule to work upon and focus for future therapeutic interventions. E3 ubiquitin ligase CHIP interacts and degrades many protein inclusions formed in neurodegenerative diseases. The presence of CHIP at various nodes of cellular protein-protein interaction network presents this molecule as a potential candidate for further research. In this review, we have explored a wide range of functionality of CHIP inside cells by a detailed presentation of its co-chaperone, E3 and E4 enzyme like functions, with central focus on its protein quality control roles in neurodegenerative diseases. We have also raised many unexplored but expected fundamental questions regarding CHIP functions, which generate hopes for its future applications in research, as well as drug discovery.
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Affiliation(s)
- Vibhuti Joshi
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur Rajasthan, India
| | - Ayeman Amanullah
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur Rajasthan, India
| | - Arun Upadhyay
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur Rajasthan, India
| | - Ribhav Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur Rajasthan, India
| | - Amit Kumar
- Centre for Biosciences and Biomedical Engineering, Indian Institute of Technology Indore Madhya Pradesh, India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur Rajasthan, India
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Interdependence of laforin and malin proteins for their stability and functions could underlie the molecular basis of locus heterogeneity in Lafora disease. J Biosci 2016; 40:863-71. [PMID: 26648032 DOI: 10.1007/s12038-015-9570-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Lafora disease (LD), an autosomal recessive and fatal form of neurodegenerative disorder, is characterized by the presence of polyglucosan inclusions in the affected tissues including the brain. LD can be caused by defects either in the EPM2A gene coding for the laforin protein phosphatase or the NHLRC1 gene coding for the malin ubiquitin ligase. Since the clinical symptoms of LD patients representing the two genetic groups are very similar and since malin is known to interact with laforin, we were curious to examine the possibility that the two proteins regulate each other's function. Using cell biological assays we demonstrate here that (i) malin promotes its own degradation via autoubiquitination, (ii) laforin prevents the auto-degradation of malin by presenting itself as a substrate and (iii) malin preferentially degrades the phosphatase-inactive laforin monomer. Our results that laforin and malin regulate each other's stability and activity offers a novel and attractive model to explain the molecular basis of locus heterogeneity observed in LD.
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15
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Goenka A, Sengupta S, Pandey R, Parihar R, Mohanta GC, Mukerji M, Ganesh S. Human satellite-III non-coding RNAs modulate heat-shock-induced transcriptional repression. J Cell Sci 2016; 129:3541-3552. [PMID: 27528402 DOI: 10.1242/jcs.189803] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 08/10/2016] [Indexed: 12/31/2022] Open
Abstract
The heat shock response is a conserved defense mechanism that protects cells from physiological stress, including thermal stress. Besides the activation of heat-shock-protein genes, the heat shock response is also known to bring about global suppression of transcription; however, the mechanism by which this occurs is poorly understood. One of the intriguing aspects of the heat shock response in human cells is the transcription of satellite-III (Sat3) long non-coding RNAs and their association with nuclear stress bodies (nSBs) of unknown function. Besides association with the Sat3 transcript, the nSBs are also known to recruit the transcription factors HSF1 and CREBBP, and several RNA-binding proteins, including the splicing factor SRSF1. We demonstrate here that the recruitment of CREBBP and SRSF1 to nSBs is Sat3-dependent, and that loss of Sat3 transcripts relieves the heat-shock-induced transcriptional repression of a few target genes. Conversely, forced expression of Sat3 transcripts results in the formation of nSBs and transcriptional repression even without a heat shock. Our results thus provide a novel insight into the regulatory role for the Sat3 transcripts in heat-shock-dependent transcriptional repression.
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Affiliation(s)
- Anshika Goenka
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Sonali Sengupta
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Rajesh Pandey
- CSIR Ayurgenomics Unit - TRISUTRA, CSIR - Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India
| | - Rashmi Parihar
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Girish Chandra Mohanta
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Mitali Mukerji
- CSIR Ayurgenomics Unit - TRISUTRA, CSIR - Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India
| | - Subramaniam Ganesh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
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Jain N, Mishra R, Ganesh S. FoxO3a-mediated autophagy is down-regulated in the laforin deficient mice, an animal model for Lafora progressive myoclonus epilepsy. Biochem Biophys Res Commun 2016; 474:321-327. [DOI: 10.1016/j.bbrc.2016.04.094] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 04/17/2016] [Indexed: 01/15/2023]
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17
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Upadhyay M, Bhadauriya P, Ganesh S. Heat shock modulates the subcellular localization, stability, and activity of HIPK2. Biochem Biophys Res Commun 2016; 472:580-4. [PMID: 26972256 DOI: 10.1016/j.bbrc.2016.03.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 03/08/2016] [Indexed: 01/01/2023]
Abstract
The homeodomain-interacting protein kinase-2 (HIPK2) is a highly conserved serine/threonine kinase and is involved in transcriptional regulation. HIPK2 is a highly unstable protein, and is kept at a low level under normal physiological conditions. However, exposure of cells to physiological stress - such as hypoxia, oxidative stress, or UV damage - is known to stabilize HIPK2, leading to the HIPK2-dependent activation of p53 and the cell death pathway. Therefore HIPK2 is also known as a stress kinase and as a stress-activated pro-apoptotic factor. We demonstrate here that exposure of cells to heat shock results in the stabilization of HIPK2 and the stabilization is mediated via K63-linked ubiquitination. Intriguingly, a sub-lethal heat shock (42 °C, 1 h) results in the cytoplasmic localization of HIPK2, while a lethal heat shock (45 °C, 1 h) results in its nuclear localization. Cells exposed to the lethal heat shock showed significantly higher levels of the p53 activity than those exposed to the sub-lethal thermal stress, suggesting that both the level and the nuclear localization are essential for the pro-apoptotic activity of HIPK2 and that the lethal heat shock could retain the HIPK2 in the nucleus to promote the cell death. Taken together our study underscores the importance of HIPK2 in stress mediated cell death, and that the HIPK2 is a generic stress kinase that gets activated by diverse set of physiological stressors.
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Affiliation(s)
- Mamta Upadhyay
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, India
| | - Pratibha Bhadauriya
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, India
| | - Subramaniam Ganesh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, India.
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18
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Sánchez-Martín P, Romá-Mateo C, Viana R, Sanz P. Ubiquitin conjugating enzyme E2-N and sequestosome-1 (p62) are components of the ubiquitination process mediated by the malin–laforin E3-ubiquitin ligase complex. Int J Biochem Cell Biol 2015; 69:204-14. [DOI: 10.1016/j.biocel.2015.10.030] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 10/28/2015] [Accepted: 10/30/2015] [Indexed: 11/26/2022]
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19
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Duran J, Guinovart JJ. Brain glycogen in health and disease. Mol Aspects Med 2015; 46:70-7. [PMID: 26344371 DOI: 10.1016/j.mam.2015.08.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 08/21/2015] [Indexed: 12/18/2022]
Abstract
Glycogen is present in the brain at much lower concentrations than in muscle or liver. However, by characterizing an animal depleted of brain glycogen, we have shown that the polysaccharide plays a key role in learning capacity and in activity-dependent changes in hippocampal synapse strength. Since glycogen is essentially found in astrocytes, the diverse roles proposed for this polysaccharide in the brain have been attributed exclusively to these cells. However, we have demonstrated that neurons have an active glycogen metabolism that contributes to tolerance to hypoxia. However, these cells can store only minute amounts of glycogen, since the progressive accumulation of this molecule leads to neuronal loss. Loss-of-function mutations in laforin and malin cause Lafora disease. This condition is characterized by the presence of high numbers of insoluble polyglucosan bodies, known as Lafora bodies, in neuronal cells. Our findings reveal that the accumulation of this aberrant glycogen accounts for the neurodegeneration and functional consequences, as well as the impaired autophagy, observed in models of this disease. Similarly glycogen synthase is responsible for the accumulation of corpora amylacea, which are polysaccharide-based aggregates present in the neurons of aged human brains. Our findings change the current view of the role of glycogen in the brain and reveal that endogenous neuronal glycogen metabolism is important under stress conditions and that neuronal glycogen accumulation contributes to neurodegenerative diseases and to aging-related corpora amylacea formation.
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Affiliation(s)
- Jordi Duran
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
| | - Joan J Guinovart
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain; Department of Biochemistry and Molecular Biology, University of Barcelona, Barcelona, Spain.
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20
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Palubinsky AM, Stankowski JN, Kale AC, Codreanu SG, Singer RJ, Liebler DC, Stanwood GD, McLaughlin B. CHIP Is an Essential Determinant of Neuronal Mitochondrial Stress Signaling. Antioxid Redox Signal 2015; 23:535-49. [PMID: 25602369 PMCID: PMC4544748 DOI: 10.1089/ars.2014.6102] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
AIMS Determine the mechanism by which C-terminus of HSC70-interacting protein (CHIP) induction alters neuronal survival under conditions of mitochondrial stress induced by oxygen glucose deprivation. RESULTS We report that animals deficient in the E3 ubiquitin ligase, CHIP, have high baseline levels of central nervous system protein oxidation and lipid peroxidation, reduced antioxidant defenses, and decreased energetic status. Stress-associated molecules typically linked to Parkinson's disease such as the mitochondrial kinase, PTEN-inducible putative kinase 1 (PINK1), and another E3 ligase, Parkin, are upregulated in brains from CHIP knockout (KO) animals. Utilizing a novel biotin-avidin capture technique, we found that the oxidation status of Parkin and the mitochondrial fission protein, dynamin-related protein 1 (Drp1), are altered in a CHIP-dependent manner. We also found that following oxygen-glucose deprivation (OGD), the expression of CHIP, PINK1, and the autophagic marker, LC3, increase and there is activation of the redox-sensitive kinase p66(shc). Under conditions of OGD, CHIP relocalizes from the cytosol to mitochondria. Mitochondria from CHIP KO mice have profound impairments in stress response induced by calcium overload, resulting in accelerated permeability transition activity. While CHIP-deficient neurons are morphologically intact, they are more susceptible to OGD consistent with a previously unknown neuroprotective role for CHIP in maintaining mitochondrial homeostasis. INNOVATION CHIP relocalization to the mitochondria is essential for the regulation of mitochondrial integrity and neuronal survival following OGD. CONCLUSIONS CHIP is an essential regulator of neuronal bioenergetics and redox tone. Altering the expression of this protein has profound effects on neuronal survival when cells are exposed to OGD.
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Affiliation(s)
- Amy M Palubinsky
- 1 Neuroscience Graduate Program, Vanderbilt Brain Institute, Vanderbilt University , Nashville, Tennessee.,2 Clinical Neuroscience Scholars Program, Vanderbilt University , Nashville, Tennessee.,3 J.B. Marshall Laboratory for Neurovascular Therapeutics, Vanderbilt University , Nashville, Tennessee.,4 Kennedy Center for Research on Human Development, Vanderbilt University , Nashville, Tennessee
| | - Jeannette N Stankowski
- 1 Neuroscience Graduate Program, Vanderbilt Brain Institute, Vanderbilt University , Nashville, Tennessee.,4 Kennedy Center for Research on Human Development, Vanderbilt University , Nashville, Tennessee.,5 Department of Neuroscience, Mayo Clinic , Jacksonville, Florida
| | - Alixandra C Kale
- 3 J.B. Marshall Laboratory for Neurovascular Therapeutics, Vanderbilt University , Nashville, Tennessee.,4 Kennedy Center for Research on Human Development, Vanderbilt University , Nashville, Tennessee.,6 Department of Neurology, Vanderbilt University , Nashville, Tennessee
| | - Simona G Codreanu
- 7 Department of Biochemistry, Vanderbilt University , Nashville, Tennessee.,8 Department of Biomedical Informatics, Vanderbilt University , Nashville, Tennessee
| | - Robert J Singer
- 3 J.B. Marshall Laboratory for Neurovascular Therapeutics, Vanderbilt University , Nashville, Tennessee.,9 Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University , Nashville, Tennessee.,10 Department of Neurosurgery, Dartmouth Hitchcock Hospital , Lebanon , New Hampshire
| | - Daniel C Liebler
- 7 Department of Biochemistry, Vanderbilt University , Nashville, Tennessee.,8 Department of Biomedical Informatics, Vanderbilt University , Nashville, Tennessee
| | - Gregg D Stanwood
- 4 Kennedy Center for Research on Human Development, Vanderbilt University , Nashville, Tennessee.,11 Department of Pharmacology, Vanderbilt University , Nashville, Tennessee
| | - BethAnn McLaughlin
- 3 J.B. Marshall Laboratory for Neurovascular Therapeutics, Vanderbilt University , Nashville, Tennessee.,4 Kennedy Center for Research on Human Development, Vanderbilt University , Nashville, Tennessee.,6 Department of Neurology, Vanderbilt University , Nashville, Tennessee.,9 Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University , Nashville, Tennessee.,11 Department of Pharmacology, Vanderbilt University , Nashville, Tennessee
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21
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Upadhyay M, Gupta S, Bhadauriya P, Ganesh S. Lafora disease proteins laforin and malin negatively regulate the HIPK2-p53 cell death pathway. Biochem Biophys Res Commun 2015; 464:106-11. [PMID: 26102034 DOI: 10.1016/j.bbrc.2015.06.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 06/02/2015] [Indexed: 01/05/2023]
Abstract
Lafora disease (LD) is an autosomal recessive, progressive, and fatal form of a neurodegenerative disorder characterized by the presence of Lafora polyglucosan bodies. LD is caused by defects in either the laforin protein phosphatase or the malin E3 ubiquitin ligase. Laforin and malin were shown play key roles in proteolytic processes, unfolded stress response, and glycogen metabolism. Therefore, the LD proteins laforin and malin are thought to function as pro-survival factors and their loss thus could result in neurodegeneration. To understand the molecular pathway leading to the cell death in LD, in the present study, we investigated the possible role of LD proteins in the p53-mediated cell death pathway. We show that loss of laforin or malin results in the increased level and activity of p53, both in cellular and animal models of LD, and that this is primarily due to the increased levels of Hipk2, a proapoptotic activator of p53. Overexpression of laforin or malin confers protection against Hipk2-mediated cell death by targeting the Hipk2 to the cytoplasmic compartment. Taken together, our study strengthens the notion that laforin and malin are pro-survival factors, and that the activation of Hipk2-p53 cell death pathway might underlie neurodegeneration in LD.
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Affiliation(s)
- Mamta Upadhyay
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
| | - Smriti Gupta
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
| | - Pratibha Bhadauriya
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
| | - Subramaniam Ganesh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India; Center of Excellence for Chemical Biology, Indian Institute of Technology, Kanpur, India.
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22
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The E3 ligase CHIP: insights into its structure and regulation. BIOMED RESEARCH INTERNATIONAL 2014; 2014:918183. [PMID: 24868554 PMCID: PMC4017836 DOI: 10.1155/2014/918183] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 04/07/2014] [Indexed: 12/21/2022]
Abstract
The carboxy-terminus of Hsc70 interacting protein (CHIP) is a cochaperone E3 ligase containing three tandem repeats of tetratricopeptide (TPR) motifs and a C-terminal U-box domain separated by a charged coiled-coil region. CHIP is known to function as a central quality control E3 ligase and regulates several proteins involved in a myriad of physiological and pathological processes. Recent studies have highlighted varied regulatory mechanisms operating on the activity of CHIP which is crucial for cellular homeostasis. In this review article, we give a concise account of our current knowledge on the biochemistry and regulation of CHIP.
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23
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Emerging role of autophagy in pediatric neurodegenerative and neurometabolic diseases. Pediatr Res 2014; 75:217-26. [PMID: 24165736 DOI: 10.1038/pr.2013.185] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 06/24/2013] [Indexed: 11/08/2022]
Abstract
Pediatric neurodegenerative diseases are a heterogeneous group of diseases that result from specific genetic and biochemical defects. In recent years, studies have revealed a wide spectrum of abnormal cellular functions that include impaired proteolysis, abnormal lipid trafficking, accumulation of lysosomal content, and mitochondrial dysfunction. Within neurons, elaborated degradation pathways such as the ubiquitin-proteasome system and the autophagy-lysosomal pathway are critical for maintaining homeostasis and normal cell function. Recent evidence suggests a pivotal role for autophagy in major adult and pediatric neurodegenerative diseases. We herein review genetic, pathological, and molecular evidence for the emerging link between autophagy dysfunction and lysosomal storage disorders such as Niemann-Pick type C, progressive myoclonic epilepsies such as Lafora disease, and leukodystrophies such as Alexander disease. We also discuss the recent discovery of genetically deranged autophagy in Vici syndrome, a multisystem disorder, and the implications for the role of autophagy in development and disease. Deciphering the exact mechanism by which autophagy contributes to disease pathology may open novel therapeutic avenues to treat neurodegeneration. To this end, an outlook on novel therapeutic approaches targeting autophagy concludes this review.
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Strnad P, Nuraldeen R, Guldiken N, Hartmann D, Mahajan V, Denk H, Haybaeck J. Broad Spectrum of Hepatocyte Inclusions in Humans, Animals, and Experimental Models. Compr Physiol 2013; 3:1393-436. [DOI: 10.1002/cphy.c120032] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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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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26
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Dimerization of the glucan phosphatase laforin requires the participation of cysteine 329. PLoS One 2013; 8:e69523. [PMID: 23922729 PMCID: PMC3724922 DOI: 10.1371/journal.pone.0069523] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 06/11/2013] [Indexed: 01/08/2023] Open
Abstract
Laforin, encoded by a gene that is mutated in Lafora Disease (LD, OMIM 254780), is a modular protein composed of a carbohydrate-binding module and a dual-specificity phosphatase domain. Laforin is the founding member of the glucan-phosphatase family and regulates the levels of phosphate present in glycogen. Multiple reports have described the capability of laforin to form dimers, although the function of these dimers and their relationship with LD remains unclear. Recent evidence suggests that laforin dimerization depends on redox conditions, suggesting that disulfide bonds are involved in laforin dimerization. Using site-directed mutagenesis we constructed laforin mutants in which individual cysteine residues were replaced by serine and then tested the ability of each protein to dimerize using recombinant protein as well as a mammalian cell culture assay. Laforin-Cys329Ser was the only Cys/Ser mutant unable to form dimers in both assays. We also generated a laforin truncation lacking the last three amino acids, laforin-Cys329X, and this truncation also failed to dimerize. Interestingly, laforin-Cys329Ser and laforin-Cys329X were able to bind glucans, and maintained wild type phosphatase activity against both exogenous and biologically relevant substrates. Furthermore, laforin-Cys329Ser was fully capable of participating in the ubiquitination process driven by a laforin-malin complex. These results suggest that dimerization is not required for laforin phosphatase activity, glucan binding, or for the formation of a functional laforin-malin complex. Cumulatively, these results suggest that cysteine 329 is specifically involved in the dimerization process of laforin. Therefore, the C329S mutant constitutes a valuable tool to analyze the physiological implications of laforin’s oligomerization.
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Turnbull J, Girard JM, Lohi H, Chan EM, Wang P, Tiberia E, Omer S, Ahmed M, Bennett C, Chakrabarty A, Tyagi A, Liu Y, Pencea N, Zhao X, Scherer SW, Ackerley CA, Minassian BA. Early-onset Lafora body disease. ACTA ACUST UNITED AC 2012; 135:2684-98. [PMID: 22961547 DOI: 10.1093/brain/aws205] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The most common progressive myoclonus epilepsies are the late infantile and late infantile-variant neuronal ceroid lipofuscinoses (onset before the age of 6 years), Unverricht-Lundborg disease (onset after the age of 6 years) and Lafora disease. Lafora disease is a distinct disorder with uniform course: onset in teenage years, followed by progressively worsening myoclonus, seizures, visual hallucinations and cognitive decline, leading to a vegetative state in status myoclonicus and death within 10 years. Biopsy reveals Lafora bodies, which are pathognomonic and not seen with any other progressive myoclonus epilepsies. Lafora bodies are aggregates of polyglucosans, poorly constructed glycogen molecules with inordinately long strands that render them insoluble. Lafora disease is caused by mutations in the EPM2A or EPM2B genes, encoding the laforin phosphatase and the malin ubiquitin ligase, respectively, two cytoplasmically active enzymes that regulate glycogen construction, ensuring symmetric expansion into a spherical shape, essential to its solubility. In this work, we report a new progressive myoclonus epilepsy associated with Lafora bodies, early-onset Lafora body disease, map its locus to chromosome 4q21.21, identify its gene and mutation and characterize the relationship of its gene product with laforin and malin. Early-onset Lafora body disease presents early, at 5 years, with dysarthria, myoclonus and ataxia. The combination of early-onset and early dysarthria strongly suggests late infantile-variant neuronal ceroid lipofuscinosis, not Lafora disease. Pathology reveals no ceroid lipofuscinosis, but Lafora bodies. The subsequent course is a typical progressive myoclonus epilepsy, though much more protracted than any infantile neuronal ceroid lipofuscinosis, or Lafora disease, patients living into the fourth decade. The mutation, c.781T>C (Phe261Leu), is in a gene of unknown function, PRDM8. We show that the PRDM8 protein interacts with laforin and malin and causes translocation of the two proteins to the nucleus. We find that Phe261Leu-PRDM8 results in excessive sequestration of laforin and malin in the nucleus and that it therefore likely represents a gain-of-function mutation that leads to an effective deficiency of cytoplasmic laforin and malin. We have identified a new progressive myoclonus epilepsy with Lafora bodies, early-onset Lafora body disease, 101 years after Lafora disease was first described. The results to date suggest that PRDM8, the early-onset Lafora body disease protein, regulates the cytoplasmic quantities of the Lafora disease enzymes.
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Affiliation(s)
- Julie Turnbull
- Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
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Singh S, Singh PK, Bhadauriya P, Ganesh S. Lafora disease E3 ubiquitin ligase malin is recruited to the processing bodies and regulates the microRNA-mediated gene silencing process via the decapping enzyme Dcp1a. RNA Biol 2012; 9:1440-9. [PMID: 23131811 DOI: 10.4161/rna.22708] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Intracellular transport, processing and stability of mRNA play critical roles in the functional physiology of the cell and defects in these processes are thought to underlie the pathogenesis in a number of neurodegenerative disorders. One of the cellular sites that regulate the mRNA half-life is the processing bodies, the dynamic cytoplasmic structures that represent the non-translating mRNA and the ribonucleoprotein complex that also control the decapping and translation of mRNA. In the present study we explored the possible role of malin E3 ubiquitin ligase in the mRNA decay pathway via the processing bodies. Defects in malin are associated with Lafora disease (LD)-a neurodegenerative disorder characterized by myoclonus seizures. We show here that malin is recruited to the processing bodies and that malin regulates the recruitment of mRNA decapping enzyme Dcp1a by promoting its degradation via the ubiquitin proteasome system. Depletion of malin results in elevated levels of Dcp1a and an altered microRNA-mediated gene silencing activity. Our study suggests that malin is one of the critical regulators of processing bodies and that defects in the mRNA processing might underlie some of the disease symptoms in LD.
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Affiliation(s)
- Sweta Singh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
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29
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Chandrasekhar V, Das S, Yadav R, Hossain S, Parihar R, Subramaniam G, Sen P. Novel Chemosensor for the Visual Detection of Copper(II) in Aqueous Solution at the ppm Level. Inorg Chem 2012; 51:8664-6. [DOI: 10.1021/ic301399a] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
| | - Sourav Das
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, India
| | - Rajeev Yadav
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, India
| | - Sakiat Hossain
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, India
| | - Rashmi Parihar
- Department of Biological
Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208 016, India
| | - Ganesh Subramaniam
- Department of Biological
Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208 016, India
| | - Pratik Sen
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, India
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Romá-Mateo C, Sanz P, Gentry MS. Deciphering the role of malin in the lafora progressive myoclonus epilepsy. IUBMB Life 2012; 64:801-8. [PMID: 22815132 DOI: 10.1002/iub.1072] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 06/15/2012] [Indexed: 12/21/2022]
Abstract
Lafora disease (LD) is a fatal, autosomal recessive neurodegenerative disorder that results in progressive myoclonus epilepsy. A hallmark of LD is the accumulation of insoluble, aberrant glycogen-like structures called Lafora bodies. LD is caused by mutations in the gene encoding the E3 ubiquitin ligase malin or the glucan phosphatase laforin. Although LD was first described in 1911, its symptoms are still lacking a consistent molecular explanation and, consequently, a cure is far from being achieved. Some data suggest that malin forms a functional complex with laforin. This complex promotes the ubiquitination of proteins involved in glycogen metabolism and misregulation of pathways involved in this process results in Lafora body formation. In addition, recent results obtained from both cell culture and LD mouse models have highlighted a role of the laforin-malin complex in the regulation of endoplasmic reticulum-stress and protein clearance pathways. These results suggest that LD should be considered as a novel member of the group of protein clearance diseases such as Parkinson's, Huntington's, or Alzheimer's, in addition to being a glycogen metabolism disease. Herein, we review the latest results concerning the role of malin in LD and attempt to decipher its function. © 2012 IUBMB IUBMB Life, 64(10): 801-808, 2012.
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Affiliation(s)
- Carlos Romá-Mateo
- Instituto de Biomedicina de Valencia, CSIC and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain
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Zeng L, Wang Y, Baba O, Zheng P, Liu Y, Liu Y. Laforin is required for the functional activation of malin in endoplasmic reticulum stress resistance in neuronal cells. FEBS J 2012; 279:2467-78. [PMID: 22578008 DOI: 10.1111/j.1742-4658.2012.08627.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Mutations in either EPM2A, the gene encoding a dual-specificity phosphatase named laforin, or NHLRC1, the gene encoding an E3 ubiquitin ligase named malin, cause Lafora disease in humans. Lafora disease is a fatal neurological disorder characterized by progressive myoclonus epilepsy, severe neurological deterioration and accumulation of poorly branched glycogen inclusions, called Lafora bodies or polyglucosan bodies, within the cell cytoplasm. The molecular mechanism underlying the neuropathogenesis of Lafora disease remains unknown. Here, we present data demonstrating that in the cells expressing low levels of laforin protein, overexpressed malin and its Lafora disease-causing missense mutants are stably polyubiquitinated. Malin and malin mutants form ubiquitin-positive aggregates in or around the nuclei of the cells in which they are expressed. Neither wild-type malin nor its mutants elicit endoplasmic reticulum stress, although the mutants exaggerate the response to endoplasmic reticulum stress. Overexpressed laforin impairs the polyubiquitination of malin while it recruits malin to polyglucosan bodies. The recruitment and activities of laforin and malin are both required for the polyglucosan body disruption. Consistently, targeted deletion of laforin in brain cells from Epm2a knockout mice increases polyubiquitinated proteins. Knockdown of Epm2a or Nhlrc1 in neuronal Neuro2a cells shows that they cooperate to allow cells to resist ER stress and apoptosis. These results reveal that a functional laforin-malin complex plays a critical role in disrupting Lafora bodies and relieving ER stress, implying that a causative pathogenic mechanism underlies their deficiency in Lafora disease.
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Affiliation(s)
- Li Zeng
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI 48109, USA
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32
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Phenotype variations in Lafora progressive myoclonus epilepsy: possible involvement of genetic modifiers? J Hum Genet 2012; 57:283-5. [PMID: 22456482 DOI: 10.1038/jhg.2012.29] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Lafora progressive myoclonus epilepsy, also known as Lafora disease (LD), is the most severe and fatal form of progressive myoclonus epilepsy with its typical onset during the late childhood or early adolescence. LD is characterized by recurrent epileptic seizures and progressive decline in intellectual function. LD can be caused by defects in any of the two known genes and the clinical features of these two genetic groups are almost identical. The past one decade has witnessed considerable success in identifying the LD genes, their mutations, the cellular functions of gene products and on molecular basis of LD. Here, we briefly review the current literature on the phenotype variations, on possible presence of genetic modifiers, and candidate modifiers as targets for therapeutic interventions in LD.
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Gentry MS, Romá-Mateo C, Sanz P. Laforin, a protein with many faces: glucan phosphatase, adapter protein, et alii. FEBS J 2012; 280:525-37. [PMID: 22364389 DOI: 10.1111/j.1742-4658.2012.08549.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lafora disease (LD) is a rare, fatal neurodegenerative disorder characterized by the accumulation of glycogen-like inclusions in the cytoplasm of cells from most tissues of affected patients. One hundred years after the first description of these inclusions, the molecular bases underlying the processes involved in LD physiopathology are finally being elucidated. The main cause of the disease is related to the activity of two proteins, the dual-specificity phosphatase laforin and the E3-ubiquitin ligase malin, which form a functional complex. Laforin is unique in humans, as it is composed of a carbohydrate-binding module attached to a cysteine-based catalytic dual-specificity phosphatase domain. Laforin directly dephosphorylates glycogen, but other proteinaceous substrates, if they exist, have remained elusive. Recently, an emerging set of laforin-binding partners apart from malin have been described, suggestive of laforin roles unrelated to its catalytic activity. Further investigations based on different transgenic mouse models have shown that the laforin-malin complex is also involved in other cellular processes, such as response to endoplasmic reticulum stress and misfolded protein clearance by the lysosomal pathway. However, controversial data and some missing links still make it difficult to assess the concrete relationship between glycogen deregulation and neuronal damage leading to the fatal symptoms observed in LD patients, such as myoclonic seizures and epilepsy. Consequently, clinical treatments are far from being achieved. In the present review, we focus on the knowledge of laforin biology, not only as a glucan phosphatase, but also as an adaptor protein involved in several physiological pathways.
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Affiliation(s)
- Matthew S Gentry
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, KY, USA
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34
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The laforin-malin complex negatively regulates glycogen synthesis by modulating cellular glucose uptake via glucose transporters. Mol Cell Biol 2011; 32:652-63. [PMID: 22124153 DOI: 10.1128/mcb.06353-11] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Lafora disease (LD), an inherited and fatal neurodegenerative disorder, is characterized by increased cellular glycogen content and the formation of abnormally branched glycogen inclusions, called Lafora bodies, in the affected tissues, including neurons. Therefore, laforin phosphatase and malin ubiquitin E3 ligase, the two proteins that are defective in LD, are thought to regulate glycogen synthesis through an unknown mechanism, the defects in which are likely to underlie some of the symptoms of LD. We show here that laforin's subcellular localization is dependent on the cellular glycogen content and that the stability of laforin is determined by the cellular ATP level, the activity of 5'-AMP-activated protein kinase, and the affinity of malin toward laforin. By using cell and animal models, we further show that the laforin-malin complex regulates cellular glucose uptake by modulating the subcellular localization of glucose transporters; loss of malin or laforin resulted in an increased abundance of glucose transporters in the plasma membrane and therefore excessive glucose uptake. Loss of laforin or malin, however, did not affect glycogen catabolism. Thus, the excessive cellular glucose level appears to be the primary trigger for the abnormally higher levels of cellular glycogen seen in LD.
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Puri R, Suzuki T, Yamakawa K, Ganesh S. Dysfunctions in endosomal–lysosomal and autophagy pathways underlie neuropathology in a mouse model for Lafora disease. Hum Mol Genet 2011; 21:175-84. [DOI: 10.1093/hmg/ddr452] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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