1
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Dubey AR, Mishra R, Jagtap YA, Kinger S, Kumar P, Dhiman R, Ghosh S, Singh S, Prasad A, Jana NR, Mishra A. Itraconazole Confers Cytoprotection Against Neurodegenerative Disease-Associated Abnormal Protein Aggregation. Mol Neurobiol 2023; 60:2397-2412. [PMID: 36656458 DOI: 10.1007/s12035-023-03230-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 01/06/2023] [Indexed: 01/20/2023]
Abstract
Cells perform regular maintenance to avoid the accumulation of misfolded proteins. Prolonged accumulation of these proteotoxic inclusions generates potential risk of ageing-related diseases such as neurodegenerative diseases. Therefore, removal of such abnormal aggregates can ensure the re-establishment of proteostasis. Ubiquitin proteasome system (UPS) actively participates in the selective removal of aberrantly folded clients with the help of complex proteasome machinery. However, specific induction of proteasome functions to remove abnormal proteins remains an open challenge. Here, we show that Itraconazole treatment induces proteasome activities and degrades the accumulation of bonafide-misfolded proteins, including heat-denatured luciferase. Exposure of Itraconazole elevates the degradation of neurodegenerative disease-associated proteins, e.g. expanded polyglutamine, mutant SOD1, and mutant α-synuclein. Our results suggest that Itraconazole treatment prevents the accumulation of neurodegenerative disease-linked misfolded proteins and generates cytoprotection. These findings reveal that Itraconazole removes abnormal proteins through sequential proteasomal activation and represents a potential protective therapeutic role against protein-misfolding neurodegenerative diseases.
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Affiliation(s)
- Ankur Rakesh Dubey
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, 342037, Rajasthan, India
| | - Ribhav Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, 342037, Rajasthan, India
| | - Yuvraj Anandrao Jagtap
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, 342037, Rajasthan, India
| | - Sumit Kinger
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, 342037, Rajasthan, India
| | - Prashant Kumar
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, 342037, Rajasthan, India
| | - Rohan Dhiman
- Laboratory of Mycobacterial Immunology, Department of Life Science, National Institute of Technology, Rourkela, Odisha, 769008, India
| | - Somnath Ghosh
- Radiation Biology & Health Sciences Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Sarika Singh
- Division of Toxicology and Experimental Medicine, Central Drug Research Institute, Lucknow, 226031, India
| | - Amit Prasad
- School of Biosciences and Bioengineering, Indian Institute of Technology Mandi, Mandi, India
| | - Nihar Ranjan Jana
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, 342037, Rajasthan, India.
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2
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Kabir MT, Uddin MS, Abdeen A, Ashraf GM, Perveen A, Hafeez A, Bin-Jumah MN, Abdel-Daim MM. Evidence Linking Protein Misfolding to Quality Control in Progressive Neurodegenerative Diseases. Curr Top Med Chem 2021; 20:2025-2043. [PMID: 32552649 DOI: 10.2174/1568026620666200618114924] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/25/2020] [Accepted: 05/05/2020] [Indexed: 12/13/2022]
Abstract
Several proteolytic systems including ubiquitin (Ub)-proteasome system (UPS), chaperonemediated autophagy (CMA), and macroautophagy are used by the mammalian cells to remove misfolded proteins (MPs). UPS mediates degradation of most of the MPs, where Ub-conjugated substrates are deubiquitinated, unfolded, and passed through the proteasome's narrow chamber, and eventually break into smaller peptides. It has been observed that the substrates that show a specific degradation signal, the KFERQ sequence motif, can be delivered to and go through CMA-mediated degradation in lysosomes. Macroautophagy can help in the degradation of substrates that are prone to aggregation and resistant to both the CMA and UPS. In the aforesaid case, cargoes are separated into autophagosomes before lysosomal hydrolase-mediated degradation. Even though the majority of the aggregated and MPs in the human proteome can be removed via cellular protein quality control (PQC), some mutant and native proteins tend to aggregate into β-sheet-rich oligomers that exhibit resistance to all identified proteolytic processes and can, therefore, grow into extracellular plaques or inclusion bodies. Indeed, the buildup of protease-resistant aggregated and MPs is a usual process underlying various protein misfolding disorders, including neurodegenerative diseases (NDs) for example Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and prion diseases. In this article, we have focused on the contribution of PQC in the degradation of pathogenic proteins in NDs.
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Affiliation(s)
| | - Md Sahab Uddin
- Department of Pharmacy, Southeast University, Dhaka, Bangladesh.,Pharmakon Neuroscience Research Network, Dhaka, Bangladesh
| | - Ahmed Abdeen
- Department of Forensic Medicine and Toxicology, Faculty of Veterinary Medicine, Benha University, Toukh 13736, Egypt
| | - Ghulam Md Ashraf
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Asma Perveen
- Glocal School of Life Sciences, Glocal University, Saharanpur, India
| | - Abdul Hafeez
- Glocal School of Pharmacy, Glocal University, Saharanpur, India
| | - May N Bin-Jumah
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, Riyadh 11474, Saudi Arabia
| | - Mohamed M Abdel-Daim
- Pharmacology Department, Faculty of Veterinary Medicine, Suez Canal University, Ismailia 41522, Egypt.,Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
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3
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Trist BG, Hilton JB, Hare DJ, Crouch PJ, Double KL. Superoxide Dismutase 1 in Health and Disease: How a Frontline Antioxidant Becomes Neurotoxic. Angew Chem Int Ed Engl 2021; 60:9215-9246. [PMID: 32144830 PMCID: PMC8247289 DOI: 10.1002/anie.202000451] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Indexed: 12/11/2022]
Abstract
Cu/Zn superoxide dismutase (SOD1) is a frontline antioxidant enzyme catalysing superoxide breakdown and is important for most forms of eukaryotic life. The evolution of aerobic respiration by mitochondria increased cellular production of superoxide, resulting in an increased reliance upon SOD1. Consistent with the importance of SOD1 for cellular health, many human diseases of the central nervous system involve perturbations in SOD1 biology. But far from providing a simple demonstration of how disease arises from SOD1 loss-of-function, attempts to elucidate pathways by which atypical SOD1 biology leads to neurodegeneration have revealed unexpectedly complex molecular characteristics delineating healthy, functional SOD1 protein from that which likely contributes to central nervous system disease. This review summarises current understanding of SOD1 biology from SOD1 genetics through to protein function and stability.
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Affiliation(s)
- Benjamin G. Trist
- Brain and Mind Centre and Discipline of PharmacologyThe University of Sydney, CamperdownSydneyNew South Wales2050Australia
| | - James B. Hilton
- Department of Pharmacology and TherapeuticsThe University of MelbourneParkvilleVictoria3052Australia
| | - Dominic J. Hare
- Brain and Mind Centre and Discipline of PharmacologyThe University of Sydney, CamperdownSydneyNew South Wales2050Australia
- School of BioSciencesThe University of MelbourneParkvilleVictoria3052Australia
- Atomic Medicine InitiativeThe University of Technology SydneyBroadwayNew South Wales2007Australia
| | - Peter J. Crouch
- Department of Pharmacology and TherapeuticsThe University of MelbourneParkvilleVictoria3052Australia
| | - Kay L. Double
- Brain and Mind Centre and Discipline of PharmacologyThe University of Sydney, CamperdownSydneyNew South Wales2050Australia
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4
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Furukawa Y. Good and Bad of Cu/Zn-Superoxide Dismutase Controlled by Metal Ions and Disulfide Bonds. CHEM LETT 2021. [DOI: 10.1246/cl.200770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Yoshiaki Furukawa
- Department of Chemistry, Keio University, 3-14-1 Hiyoshi, Kohoku, Kanagawa 223-8522, Japan
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5
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Trist BG, Hilton JB, Hare DJ, Crouch PJ, Double KL. Superoxide Dismutase 1 in Health and Disease: How a Frontline Antioxidant Becomes Neurotoxic. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202000451] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Benjamin G. Trist
- Brain and Mind Centre and Discipline of Pharmacology The University of Sydney, Camperdown Sydney New South Wales 2050 Australia
| | - James B. Hilton
- Department of Pharmacology and Therapeutics The University of Melbourne Parkville Victoria 3052 Australia
| | - Dominic J. Hare
- Brain and Mind Centre and Discipline of Pharmacology The University of Sydney, Camperdown Sydney New South Wales 2050 Australia
- School of BioSciences The University of Melbourne Parkville Victoria 3052 Australia
- Atomic Medicine Initiative The University of Technology Sydney Broadway New South Wales 2007 Australia
| | - Peter J. Crouch
- Department of Pharmacology and Therapeutics The University of Melbourne Parkville Victoria 3052 Australia
| | - Kay L. Double
- Brain and Mind Centre and Discipline of Pharmacology The University of Sydney, Camperdown Sydney New South Wales 2050 Australia
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6
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Gertsman I, Wuu J, McAlonis-Downes M, Ghassemian M, Ling K, Rigo F, Bennett F, Benatar M, Miller TM, Da Cruz S. An endogenous peptide marker differentiates SOD1 stability and facilitates pharmacodynamic monitoring in SOD1 amyotrophic lateral sclerosis. JCI Insight 2019; 4:122768. [PMID: 31092730 DOI: 10.1172/jci.insight.122768] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 04/04/2019] [Indexed: 12/12/2022] Open
Abstract
The discovery of novel biomarkers has emerged as a critical need for therapeutic development in amyotrophic lateral sclerosis (ALS). For some subsets of ALS, such as the genetic superoxide dismutase 1 (SOD1) form, exciting new treatment strategies, such as antisense oligonucleotide-mediated (ASO-mediated) SOD1 silencing, are being tested in clinical trials, so the identification of pharmacodynamic biomarkers for therapeutic monitoring is essential. We identify increased levels of a 7-amino acid endogenous peptide of SOD1 in cerebrospinal fluid (CSF) of human SOD1 mutation carriers but not in other neurological cases or nondiseased controls. Levels of peptide elevation vary based on the specific SOD1 mutation (ranging from 1.1-fold greater than control in D90A to nearly 30-fold greater in V148G) and correlate with previously published measurements of SOD1 stability. Using a mass spectrometry-based method (liquid chromatography-mass spectrometry), we quantified peptides in both extracellular samples (CSF) and intracellular samples (spinal cord from rat) to demonstrate that the peptide distinguishes mutation-specific differences in intracellular SOD1 degradation. Furthermore, 80% and 63% reductions of the peptide were measured in SOD1G93A and SOD1H46R rat CSF samples, respectively, following treatment with ASO, with an improved correlation to mRNA levels in spinal cords compared with the ELISA measuring intact SOD1 protein. These data demonstrate the potential of this peptide as a pharmacodynamic biomarker.
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Affiliation(s)
- Ilya Gertsman
- Biochemical Genetics and Metabolomics Laboratory, Department of Pediatrics, UCSD, La Jolla, California, USA.,Clarus Analytical, LLC, San Diego, California, USA
| | - Joanne Wuu
- Department of Neurology, University of Miami, Miami, Florida, USA
| | | | - Majid Ghassemian
- Biomolecular/Proteomics Mass Spectrometry Facility, Department of Chemistry and Biochemistry, UCSD, La Jolla, California, USA
| | - Karen Ling
- Ionis Pharmaceuticals, Carlsbad, California, USA
| | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, California, USA
| | | | - Michael Benatar
- Department of Neurology, University of Miami, Miami, Florida, USA
| | - Timothy M Miller
- Department of Neurology, Washington University in St. Louis, St. Louis, Missouri, USA
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7
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Ruegsegger C, Saxena S. Proteostasis impairment in ALS. Brain Res 2016; 1648:571-579. [PMID: 27033833 DOI: 10.1016/j.brainres.2016.03.032] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Revised: 03/20/2016] [Accepted: 03/21/2016] [Indexed: 12/13/2022]
Abstract
In physiological conditions the maintenance of the cellular proteome is a prerequisite for optimal cell functioning and cell survival. Additionally, cells need to constantly sense and adapt to their changing environment and associated stressors. Cells achieve this via a set of molecular chaperones, protein clearance pathways as well as stress-associated signaling networks which work together to prevent protein misfolding, its aggregation and accumulation in subcellular compartments. These processes together form the proteostasis network which helps in maintaining cellular proteostasis. Imbalance or impairment in this processes is directly linked to ageing associated disorders such as diabetes, cancer, stroke, metabolic disorders, pulmonary fibrosis, inflammation and neurodegenerative diseases. In this review, we provide insights into the proteostasis process and how its failure governs neurodegenerative disorders with a special focus on Amyotrophic lateral sclerosis (ALS). This article is part of a Special Issue entitled SI:ER stress.
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Affiliation(s)
- Céline Ruegsegger
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012 Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, CH-3012 Bern, Switzerland
| | - Smita Saxena
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012 Bern, Switzerland.
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8
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Rao G, Croft B, Teng C, Awasthi V. Ubiquitin-Proteasome System in Neurodegenerative Disorders. JOURNAL OF DRUG METABOLISM & TOXICOLOGY 2015; 6:187. [PMID: 30761219 PMCID: PMC6370320 DOI: 10.4172/2157-7609.1000187] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cellular proteostasis is a highly dynamic process and is primarily carried out by the degradation tools of ubiquitin-proteasome system (UPS). Abnormalities in UPS function result in the accumulation of damaged or misfolded proteins which can form intra- and extracellular aggregated proteinaceous deposits leading to cellular dysfunction and/or death. Deposition of abnormal protein aggregates and the cellular inability to clear them have been implicated in the pathogenesis of a number of neurodegenerative disorders such as Alzheimer's and Parkinson's. Contrary to the upregulation of proteasome function in oncogenesis and the use of proteasome inhibition as a therapeutic strategy, activation of proteasome function would serve therapeutic objectives of treatment of neurodegenerative diseases. This review describes the current understanding of the role of the proteasome in neurodegenerative disorders and potential utility of proteasomal modulation therein.
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Affiliation(s)
- Geeta Rao
- Department of Pharmaceutical Sciences, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Brandon Croft
- Department of Pharmaceutical Sciences, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Chengwen Teng
- Department of Pharmaceutical Sciences, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Vibhudutta Awasthi
- Department of Pharmaceutical Sciences, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
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9
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Degradation of misfolded proteins in neurodegenerative diseases: therapeutic targets and strategies. Exp Mol Med 2015; 47:e147. [PMID: 25766616 PMCID: PMC4351408 DOI: 10.1038/emm.2014.117] [Citation(s) in RCA: 567] [Impact Index Per Article: 63.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 11/19/2014] [Indexed: 12/13/2022] Open
Abstract
Mammalian cells remove misfolded proteins using various proteolytic systems, including the ubiquitin (Ub)-proteasome system (UPS), chaperone mediated autophagy (CMA) and macroautophagy. The majority of misfolded proteins are degraded by the UPS, in which Ub-conjugated substrates are deubiquitinated, unfolded and cleaved into small peptides when passing through the narrow chamber of the proteasome. The substrates that expose a specific degradation signal, the KFERQ sequence motif, can be delivered to and degraded in lysosomes via the CMA. Aggregation-prone substrates resistant to both the UPS and the CMA can be degraded by macroautophagy, in which cargoes are segregated into autophagosomes before degradation by lysosomal hydrolases. Although most misfolded and aggregated proteins in the human proteome can be degraded by cellular protein quality control, some native and mutant proteins prone to aggregation into β-sheet-enriched oligomers are resistant to all known proteolytic pathways and can thus grow into inclusion bodies or extracellular plaques. The accumulation of protease-resistant misfolded and aggregated proteins is a common mechanism underlying protein misfolding disorders, including neurodegenerative diseases such as Huntington's disease (HD), Alzheimer's disease (AD), Parkinson's disease (PD), prion diseases and Amyotrophic Lateral Sclerosis (ALS). In this review, we provide an overview of the proteolytic pathways in neurons, with an emphasis on the UPS, CMA and macroautophagy, and discuss the role of protein quality control in the degradation of pathogenic proteins in neurodegenerative diseases. Additionally, we examine existing putative therapeutic strategies to efficiently remove cytotoxic proteins from degenerating neurons.
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10
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Hilton JB, White AR, Crouch PJ. Metal-deficient SOD1 in amyotrophic lateral sclerosis. J Mol Med (Berl) 2015; 93:481-7. [PMID: 25754173 PMCID: PMC4408375 DOI: 10.1007/s00109-015-1273-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/24/2015] [Accepted: 02/25/2015] [Indexed: 12/13/2022]
Abstract
Mutations to the ubiquitous antioxidant enzyme Cu/Zn superoxide dismutase (SOD1) were the first established genetic cause of the fatal, adult-onset neurodegenerative disease amyotrophic lateral sclerosis (ALS). It is widely accepted that these mutations do not cause ALS via a loss of antioxidant function, but elucidating the alternate toxic gain of function has proven to be elusive. Under physiological conditions, SOD1 binds one copper ion and one zinc ion per monomer to form a highly stable and functional homodimer, but there is now ample evidence to indicate aberrant persistence of SOD1 in an intermediate metal-deficient state may contribute to the protein’s involvement in ALS. This review briefly discusses some of the data to support a role for metal-deficient SOD1 in the development of ALS and some of the outcomes from drug development studies that have aimed to modify the symptoms of ALS by targeting the metal state of SOD1. The implications for the metal state of SOD1 in cases of sporadic ALS that do not involve mutant SOD1 are also discussed.
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Affiliation(s)
- James B Hilton
- Department of Pathology, The University of Melbourne, Melbourne, Victoria, 3010, Australia
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11
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Lystad AH, Simonsen A. Assays to monitor aggrephagy. Methods 2015; 75:112-9. [DOI: 10.1016/j.ymeth.2014.12.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 12/12/2014] [Accepted: 12/22/2014] [Indexed: 12/15/2022] Open
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12
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Inhibition of Mitochondrial Clearance and Cu/Zn-SOD Activity Enhance 6-Hydroxydopamine-Induced Neuronal Apoptosis. Mol Neurobiol 2015; 53:777-791. [DOI: 10.1007/s12035-014-9087-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 12/29/2014] [Indexed: 01/19/2023]
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13
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Frahm GE, Smith DGS, Kane A, Lorbetskie B, Cyr TD, Girard M, Johnston MJW. Determination of supplier-to-supplier and lot-to-lot variability in glycation of recombinant human serum albumin expressed in Oryza sativa. PLoS One 2014; 9:e109893. [PMID: 25299339 PMCID: PMC4192584 DOI: 10.1371/journal.pone.0109893] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 09/06/2014] [Indexed: 01/11/2023] Open
Abstract
The use of different expression systems to produce the same recombinant human protein can result in expression-dependent chemical modifications (CMs) leading to variability of structure, stability and immunogenicity. Of particular interest are recombinant human proteins expressed in plant-based systems, which have shown particularly high CM variability. In studies presented here, recombinant human serum albumins (rHSA) produced in Oryza sativa (Asian rice) (OsrHSA) from a number of suppliers have been extensively characterized and compared to plasma-derived HSA (pHSA) and rHSA expressed in yeast (Pichia pastoris and Saccharomyces cerevisiae). The heterogeneity of each sample was evaluated using size exclusion chromatography (SEC), reversed-phase high-performance liquid chromatography (RP-HPLC) and capillary electrophoresis (CE). Modifications of the samples were identified by liquid chromatography-mass spectrometry (LC-MS). The secondary and tertiary structure of the albumin samples were assessed with far U/V circular dichroism spectropolarimetry (far U/V CD) and fluorescence spectroscopy, respectively. Far U/V CD and fluorescence analyses were also used to assess thermal stability and drug binding. High molecular weight aggregates in OsrHSA samples were detected with SEC and supplier-to-supplier variability and, more critically, lot-to-lot variability in one manufactures supplied products were identified. LC-MS analysis identified a greater number of hexose-glycated arginine and lysine residues on OsrHSA compared to pHSA or rHSA expressed in yeast. This analysis also showed supplier-to-supplier and lot-to-lot variability in the degree of glycation at specific lysine and arginine residues for OsrHSA. Both the number of glycated residues and the degree of glycation correlated positively with the quantity of non-monomeric species and the chromatographic profiles of the samples. Tertiary structural changes were observed for most OsrHSA samples which correlated well with the degree of arginine/lysine glycation. The extensive glycation of OsrHSA from multiple suppliers may have further implications for the use of OsrHSA as a therapeutic product.
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Affiliation(s)
- Grant E. Frahm
- Centre for Biologics Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada
| | - Daryl G. S. Smith
- Centre for Biologics Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada
| | - Anita Kane
- Centre for Biologics Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada
| | - Barry Lorbetskie
- Centre for Biologics Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada
| | - Terry D. Cyr
- Centre for Biologics Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada
| | - Michel Girard
- Centre for Biologics Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada
| | - Michael J. W. Johnston
- Centre for Biologics Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada
- * E-mail:
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14
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Fecto F, Esengul YT, Siddique T. Protein recycling pathways in neurodegenerative diseases. ALZHEIMERS RESEARCH & THERAPY 2014; 6:13. [PMID: 25031631 PMCID: PMC4055009 DOI: 10.1186/alzrt243] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Many progressive neurodegenerative diseases, including Alzheimer disease, Parkinson disease, Huntington disease, amyotrophic lateral sclerosis, and frontotemporal lobe dementia, are associated with the formation of insoluble intracellular proteinaceous inclusions. It is therefore imperative to understand the factors that regulate normal, as well as abnormal, protein recycling in neurons. Dysfunction of the ubiquitin-proteasome or autophagy pathways might contribute to the pathology of various neurodegenerative diseases. Induction of these pathways may offer a rational therapeutic strategy for a number of these diseases.
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Affiliation(s)
- Faisal Fecto
- Division of Neuromuscular Medicine, Davee Department of Neurology and Clinical Neurosciences, Northwestern University Feinberg School of Medicine, Tarry Building, Room 13-715, 303 East Chicago Avenue, Chicago, IL 60611, USA
| | - Y Taylan Esengul
- Division of Neuromuscular Medicine, Davee Department of Neurology and Clinical Neurosciences, Northwestern University Feinberg School of Medicine, Tarry Building, Room 13-715, 303 East Chicago Avenue, Chicago, IL 60611, USA
| | - Teepu Siddique
- Division of Neuromuscular Medicine, Davee Department of Neurology and Clinical Neurosciences, Northwestern University Feinberg School of Medicine, Tarry Building, Room 13-715, 303 East Chicago Avenue, Chicago, IL 60611, USA ; Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL 60611, USA ; Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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15
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Dal Vechio FH, Cerqueira F, Augusto O, Lopes R, Demasi M. Peptides that activate the 20S proteasome by gate opening increased oxidized protein removal and reduced protein aggregation. Free Radic Biol Med 2014; 67:304-13. [PMID: 24291399 DOI: 10.1016/j.freeradbiomed.2013.11.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 11/01/2013] [Accepted: 11/18/2013] [Indexed: 12/22/2022]
Abstract
The proteasome is a multicatalytic protease that is responsible for the degradation of the majority of intracellular proteins. Its role is correlated with several major regulatory pathways that are involved in cell cycle control, signaling, and antigen presentation, as well as in the removal of oxidatively damaged proteins. Although several proteasomal catalytic inhibitors have been described, very few activators have been reported to date. Some reports in the literature highlight the cellular protective effects of proteasome activation against oxidative stress and its effect on increased life span. In this work, we describe a peptide named proteasome-activating peptide 1 (PAP1), which increases the chymotrypsin-like proteasomal catalytic activity and, consequently, proteolytic rates both in vitro and in culture. PAP1 proteasomal activation is mediated by the opening of the proteasomal catalytic chamber. We also demonstrate that the observed proteasomal activation protected cells from oxidative stress; further, PAP1 prevented protein aggregation in a cellular model of amyotrophic lateral sclerosis. The role of 20SPT gate opening underlying protection against oxidative stress was also explored in yeast cells. The present data indicate the importance of proteasomal activators as potential drugs for the treatment of pathologies associated with the impaired removal of damaged proteins, which is observed in many neurodegenerative diseases.
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Affiliation(s)
- Francisco H Dal Vechio
- Laboratório de Bioquímica e Biofísica, Instituto Butantan, São Paulo, SP 05503-001, Brazil
| | - Fernanda Cerqueira
- Laboratório Especial de Toxinologia Aplicada, Instituto Butantan, São Paulo, SP 05503-001, Brazil
| | - Ohara Augusto
- Laboratório Especial de Toxinologia Aplicada, Instituto Butantan, São Paulo, SP 05503-001, Brazil
| | - Robson Lopes
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Marilene Demasi
- Laboratório de Bioquímica e Biofísica, Instituto Butantan, São Paulo, SP 05503-001, Brazil.
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16
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Disulfide scrambling in superoxide dismutase 1 reduces its cytotoxic effect in cultured cells and promotes protein aggregation. PLoS One 2013; 8:e78060. [PMID: 24143259 PMCID: PMC3797058 DOI: 10.1371/journal.pone.0078060] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 09/16/2013] [Indexed: 01/17/2023] Open
Abstract
Mutations in the gene coding for superoxide dismutase 1 (SOD1) are associated with familiar forms of the neurodegenerative disease amyotrophic lateral sclerosis (ALS). These mutations are believed to result in a “gain of toxic function”, leading to neuronal degeneration. The exact mechanism is still unknown, but misfolding/aggregation events are generally acknowledged as important pathological events in this process. Recently, we observed that demetallated apoSOD1, with cysteine 6 and 111 substituted for alanine, is toxic to cultured neuroblastoma cells. This toxicity depended on an intact, high affinity Zn2+ site. It was therefor contradictory to discover that wild-type apoSOD1 was not toxic, despite of its high affinity for Zn2+. This inconsistency was hypothesized to originate from erroneous disulfide formation involving C6 and C111. Using high resolution non-reducing SDS-PAGE, we have in this study demonstrated that the inability of wild-type apoSOD1 to cause cell death stems from formation of non-native intra-molecular disulfides. Moreover, monomeric apoSOD1 variants capable of such disulfide scrambling aggregated into ThT positive oligomers under physiological conditions without agitation. The oligomers were stabilized by inter-molecular disulfides and morphologically resembled what has in other neurodegenerative diseases been termed protofibrils. Disulfide scrambling thus appears to be an important event for misfolding and aggregation of SOD1, but may also be significant for protein function involving cysteines, e.g. mitochondrial import and copper loading.
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Kim SH, Jung SY, Lee KW, Lee SH, Cai M, Choi SM, Yang EJ. Bee venom effects on ubiquitin proteasome system in hSOD1(G85R)-expressing NSC34 motor neuron cells. Altern Ther Health Med 2013; 13:179. [PMID: 23866691 PMCID: PMC3722004 DOI: 10.1186/1472-6882-13-179] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 07/11/2013] [Indexed: 12/02/2022]
Abstract
Background Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that results from a progressive loss of motor neurons. Familial ALS (fALS) is caused by missense mutations in Cu, Zn-superoxide dismutase 1 (SOD1) that frequently result in the accumulation of mutant protein aggregates that are associated with impairments in the ubiquitin-proteasome system (UPS). UPS impairment has been implicated in many neurological disorders. Bee venom (BV) extracted from honey bees has been used as a traditional medicine for treating inflammatory diseases and has been shown to attenuate the neuroinflammatory events that occur in a symptomatic ALS animal model. Methods NSC34 cells were transiently transfected with a WT or G85R hSOD1-GFP construct for 24 hrs and then stimulated with 2.5 μg/ml BV for 24 hrs. To determine whether a SOD1 mutation affects UPS function in NSC34 cells, we examined proteasome activity and performed western blotting and immunofluorescence using specific antibodies, such as anti-misfolded SOD1, anti-ubiquitin, anti-GRP78, anti-LC3, and anti-ISG15 antibodies. Results We found that GFP-hSOD1G85R overexpression induced SOD1 inclusions and reduced proteasome activity compared with the overexpression of GFP alone in NSC34 motor neuronal cells. In addition, we also observed that BV treatment restored proteasome activity and reduced the accumulation of ubiquitinated and misfolded SOD1 in GFP-hSOD1G85R-overexpressing NSC34 motor neuronal cells. However, BV treatment did not activate the autophagic pathway in these cells. Conclusion Our findings suggest that BV may rescue the impairment of the UPS in ALS models.
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Redler RL, Dokholyan NV. The complex molecular biology of amyotrophic lateral sclerosis (ALS). PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 107:215-62. [PMID: 22482452 DOI: 10.1016/b978-0-12-385883-2.00002-3] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disorder that causes selective death of motor neurons followed by paralysis and death. A subset of ALS cases is caused by mutations in the gene for Cu, Zn superoxide dismutase (SOD1), which impart a toxic gain of function to this antioxidant enzyme. This neurotoxic property is widely believed to stem from an increased propensity to misfold and aggregate caused by decreased stability of the native homodimer or a tendency to lose stabilizing posttranslational modifications. Study of the molecular mechanisms of SOD1-related ALS has revealed a complex array of interconnected pathological processes, including glutamate excitotoxicity, dysregulation of neurotrophic factors and axon guidance proteins, axonal transport defects, mitochondrial dysfunction, deficient protein quality control, and aberrant RNA processing. Many of these pathologies are directly exacerbated by misfolded and aggregated SOD1 and/or cytosolic calcium overload, suggesting the primacy of these events in disease etiology and their potential as targets for therapeutic intervention.
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Affiliation(s)
- Rachel L Redler
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA
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Frahm GE, Cyr TD, Smith DGS, Walrond LD, Johnston MJW. Investigation of the Differences in Thermal Stability of Two Recombinant Human Serum Albumins with 1,2-Dipalmitoyl-sn-glycero-3-phosphocholine Liposomes by UV Circular Dichroism Spectropolarimetry. J Phys Chem B 2012; 116:4661-70. [DOI: 10.1021/jp2125729] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Grant E. Frahm
- Centre for
Vaccine Evaluation, Biologics and Genetic
Therapies Directorate, Health Canada, 251
Sir Frederick Banting Driveway, Ottawa, ON K1A 0K9, Canada
| | - Terry D. Cyr
- Centre for
Vaccine Evaluation, Biologics and Genetic
Therapies Directorate, Health Canada, 251
Sir Frederick Banting Driveway, Ottawa, ON K1A 0K9, Canada
| | - Daryl G. S. Smith
- Centre for
Vaccine Evaluation, Biologics and Genetic
Therapies Directorate, Health Canada, 251
Sir Frederick Banting Driveway, Ottawa, ON K1A 0K9, Canada
| | - Lisa D. Walrond
- Centre for
Vaccine Evaluation, Biologics and Genetic
Therapies Directorate, Health Canada, 251
Sir Frederick Banting Driveway, Ottawa, ON K1A 0K9, Canada
| | - Michael J. W. Johnston
- Centre for
Vaccine Evaluation, Biologics and Genetic
Therapies Directorate, Health Canada, 251
Sir Frederick Banting Driveway, Ottawa, ON K1A 0K9, Canada
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Fecto F, Siddique T. UBQLN2/P62 cellular recycling pathways in amyotrophic lateral sclerosis and frontotemporal dementia. Muscle Nerve 2012; 45:157-62. [DOI: 10.1002/mus.23278] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Chen X, Shang H, Qiu X, Fujiwara N, Cui L, Li XM, Gao TM, Kong J. Oxidative modification of cysteine 111 promotes disulfide bond-independent aggregation of SOD1. Neurochem Res 2012; 37:835-45. [PMID: 22219129 DOI: 10.1007/s11064-011-0679-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2011] [Revised: 11/28/2011] [Accepted: 12/15/2011] [Indexed: 11/25/2022]
Abstract
Converging evidence indicates that SOD1 aggregation is a common feature of mutant SOD1-linked fALS, and seems to be directly related to the gain-of-function toxic property. However, the mechanism inducing the aggregation is not understood. To study the contribution of oxidative modification of cysteine residues in SOD1 aggregation, we systematically examined the redox state of SOD1 cysteine residues in the G37R transgenic mouse model at different stages of the disease and under oxidative stress induced by H₂O₂. Our data suggest that under normal circumstance, cysteine 111 residue in SOD1 is free; however, under oxidative stress, it is prone to oxidative modification by providing the thiolate anion (S-). With the progression of the disease, increased levels of oxidative insults facilitated the oxidation of thiol groups of cysteine residues; human mutant SOD1 could generate an upper shift band in reducing SDS-PAGE, which turned out to be a Cys111-peroxidized SOD1 species. We also detected the formation of SOD1 multimers at different stages of the disease, and found that accumulated oxidative stress facilitated the formation of aggregates, which were not mediated by disulfide bond. This oxidative modification of cysteine 111 therefore promotes the formation of disulfide bond-independent aggregation of SOD1.
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Affiliation(s)
- Xueping Chen
- Department of Human Anatomy and Cell Science, University of Manitoba, 745 Bannatyne Avenue, Winnipeg, MB R3E 0J9, Canada
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Kumar P, Pradhan K, Karunya R, Ambasta RK, Querfurth HW. Cross-functional E3 ligases Parkin and C-terminus Hsp70-interacting protein in neurodegenerative disorders. J Neurochem 2011; 120:350-70. [DOI: 10.1111/j.1471-4159.2011.07588.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Johnston MJW, Frahm G, Li X, Durocher Y, Hefford MA. O-Linked Glycosylation Leads to Decreased Thermal Stability of Interferon Alpha 2b as Measured by Two Orthogonal Techniques. Pharm Res 2011; 28:1661-7. [DOI: 10.1007/s11095-011-0402-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Accepted: 02/14/2011] [Indexed: 10/18/2022]
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Kim HK, Chung YW, Chock PB, Yim MB. Effect of CCS on the accumulation of FALS SOD1 mutant-containing aggregates and on mitochondrial translocation of SOD1 mutants: implication of a free radical hypothesis. Arch Biochem Biophys 2011; 509:177-85. [PMID: 21354101 DOI: 10.1016/j.abb.2011.02.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 02/10/2011] [Accepted: 02/16/2011] [Indexed: 11/16/2022]
Abstract
Missense mutations of SOD1 are linked to familial amyotrophic lateral sclerosis (FALS) through a yet-to-be identified toxic-gain-of-function. One of the proposed mechanisms involves enhanced aggregate formation. However, a recent study showed that dual transgenic mice overexpressing both G93A and CCS copper chaperone (G93A/CCS) exhibit no SOD1-positive aggregates yet show accelerated FALS symptoms with enhanced mitochondrial pathology compared to G93A mice. Using a dicistronic mRNA to simultaneously generate hSOD1 mutants, G93A, A4V and G85R, and hCCS in AAV293 cells, we revealed: (i) CCS is degraded primarily via a macroautophagy pathway. It forms a stable heterodimer with inactive G85R, and via its novel copper chaperone-independent molecular chaperone activity facilitates G85R degradation via a macroautophagy-mediated pathway. For active G93A and A4V, CCS catalyzes their maturation to form active and soluble homodimers. (ii) CCS reduces, under non-oxidative conditions, yet facilitates in the presence of H(2)O(2), mitochondrial translocation of inactive SOD1 mutants. These results, together with previous reports showing FALS SOD1 mutants enhanced free radical-generating activity, provide a mechanistic explanation for the observations with G93A/CCS dual transgenic mice and suggest that free radical generation by FALS SOD1, enhanced by CCS, may, in part, be responsible for the FALS SOD1 mutant-linked aggregation, mitochondrial translocation, and degradation.
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Affiliation(s)
- Ha Kun Kim
- Laboratory of Biochemistry, NHLBI, National Institutes of Health, Bethesda, MD 20892-8012, USA
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Kabashi E, Agar JN, Hong Y, Taylor DM, Minotti S, Figlewicz DA, Durham HD. Proteasomes remain intact, but show early focal alteration in their composition in a mouse model of amyotrophic lateral sclerosis. J Neurochem 2010; 105:2353-66. [PMID: 18315558 DOI: 10.1111/j.1471-4159.2008.05317.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In amyotrophic lateral sclerosis caused by mutations in Cu/Zn-superoxide dismutase (SOD1), altered solubility and aggregation of the mutant protein implicates failure of pathways for detecting and catabolizing misfolded proteins. Our previous studies demonstrated early reduction of proteasome-mediated proteolytic activity in lumbar spinal cord of SOD1(G93A) transgenic mice, tissue particularly vulnerable to disease. The purpose of this study was to identify any underlying abnormalities in proteasomal structure. In lumbar spinal cord of pre-symptomatic mice [postnatal day 45 (P45) and P75], normal levels of structural 20S alpha subunits were incorporated into 20S/26S proteasomes; however, proteasomal complexes separated by native gel electrophoresis showed decreased immunoreactivity with antibodies to beta3, a structural subunit of the 20S proteasome core, and beta5, the subunit with chymotrypsin-like activity. This occurred prior to increase in beta5i immunoproteasomal subunit. mRNA levels were maintained and no association of mutant SOD1 with proteasomes was identified, implicating post-transcriptional mechanisms. mRNAs also were maintained in laser captured motor neurons at a later stage of disease (P100) in which multiple 20S proteins are reduced relative to the surrounding neuropil. Increase in detergent-insoluble, ubiquitinated proteins at P75 provided further evidence of stress on mechanisms of protein quality control in multiple cell types prior to significant motor neuron death.
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Affiliation(s)
- Edor Kabashi
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
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Role of ubiquitin-proteasome-mediated proteolysis in nervous system disease. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2010; 1809:128-40. [PMID: 20674814 DOI: 10.1016/j.bbagrm.2010.07.006] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2009] [Revised: 07/15/2010] [Accepted: 07/21/2010] [Indexed: 12/12/2022]
Abstract
Proteolysis by the ubiquitin-proteasome pathway (UPP) is now widely recognized as a molecular mechanism controlling myriad normal functions in the nervous system. Also, this pathway is intimately linked to many diseases and disorders of the brain. Among the diseases connected to the UPP are neurodegenerative disorders such as Alzheimer's, Parkinson's and Huntington's diseases. Perturbation in the UPP is also believed to play a causative role in mental disorders such as Angelman syndrome. The pathology of neurodegenerative diseases is characterized by abnormal deposition of insoluble protein aggregates or inclusion bodies within neurons. The ubiquitinated protein aggregates are believed to result from dysfunction of the UPP or from structural changes in the protein substrates which prevent their recognition and degradation by the UPP. An early effect of abnormal UPP in diseases of the nervous system is likely to be impairment of synaptic function. Here we discuss the UPP and its physiological roles in the nervous system and how alterations in the UPP relate to development of nervous system diseases. This article is part of a Special Issue entitled The 26S Proteasome: When degradation is just not enough!
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You Z, Cao X, Taylor AB, Hart PJ, Levine RL. Characterization of a covalent polysulfane bridge in copper-zinc superoxide dismutase . Biochemistry 2010; 49:1191-8. [PMID: 20052996 DOI: 10.1021/bi901844d] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In the course of studies on human copper-zinc superoxide dismutase (SOD1), we observed a modified form of the protein whose mass was increased by 158 mass units. The covalent modification was characterized, and we established that it is a novel heptasulfane bridge connecting the two Cys111 residues in the SOD1 homodimer. The heptasulfane bridge was visualized directly in the crystal structure of a recombinant human mutant SOD1, H46R/H48Q, produced in yeast. The modification is reversible, with the bridge being cleaved by thiols, by cyanide, and by unfolding of the protein to expose the polysulfane. The polysulfane bridge can be introduced in vitro by incubation of purified SOD1 with elemental sulfur, even under anaerobic conditions and in the presence of a metal chelator. Because polysulfanes and polysulfides can catalyze the generation of reactive oxygen and sulfur species, the modification may endow SOD1 with a toxic gain of function.
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Affiliation(s)
- Zheng You
- Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892, USA
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Accelerated formation of alpha-synuclein oligomers by concerted action of the 20S proteasome and familial Parkinson mutations. J Bioenerg Biomembr 2010; 42:85-95. [PMID: 20148295 DOI: 10.1007/s10863-009-9258-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Accepted: 12/01/2009] [Indexed: 12/20/2022]
Abstract
A hallmark of Parkinson disease (PD) is the formation of intracellular protein inclusions called Lewy bodies that also contain mitochondria. alpha-Synuclein (alpha Syn) is a major protein component of Lewy bodies, where it is in an amyloid conformation and a significant fraction is truncated by poorly understood proteolytic events. Previously, we demonstrated that the 20S proteasome cleaves alpha Syn in vitro to produce fragments like those observed in Lewy bodies and that the fragments accelerate the formation of amyloid fibrils from full-length alpha Syn. Three point mutations in alpha Syn are associated with early-onset familial PD: A30P, E46K, and A53T. However, these mutations have very different effects on the amyloidogenicity and vesicle-binding activity of alpha Syn, suggesting neither of these processes directly correlate with neurodegeneration. Here, we evaluate the effect of the disease-associated mutations on the fragmentation, conformation, and association reactions of alpha Syn in the presence of the 20S proteasome and liposomes. The 20S proteasome produced the C-terminal fragments from both the mutant and wildtype alpha Syn. These truncations accelerated fibrillization of all alpha-synucleins, but again there was no clear correlation between the PD-associated mutations and amyloid formation in the presence of liposomes. Recent data suggests that cellular toxicity is caused by a soluble oligomeric species, which is a precursor to the amyloid form and is immunologically distinguishable from both soluble monomeric and amyloid forms of alpha Syn. Notably, the rate of formation of the soluble, presumptively cytotoxic oligomers correlated with the disease-associated mutations when both 20S proteasome and liposomes were present. Under these conditions, the wildtype protein was also cleaved and formed the oligomeric structures, albeit at a slower rate, suggesting that 20S-mediated truncation of alpha Syn may play a role in sporadic PD as well. Evaluation of the biochemical reactions of the PD-associated alpha-synuclein mutants in our in vitro system provides insight into the possible pathogenetic mechanism of both familial and sporadic PD.
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Gal J, Ström AL, Kwinter DM, Kilty R, Zhang J, Shi P, Fu W, Wooten MW, Zhu H. Sequestosome 1/p62 links familial ALS mutant SOD1 to LC3 via an ubiquitin-independent mechanism. J Neurochem 2009; 111:1062-73. [PMID: 19765191 DOI: 10.1111/j.1471-4159.2009.06388.x] [Citation(s) in RCA: 148] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The p62/sequestosome 1 protein has been identified as a component of pathological protein inclusions in neurodegenerative diseases including amyotrophic lateral sclerosis (ALS). P62 has also been implicated in autophagy, a process of mass degradation of intracellular proteins and organelles. Autophagy is a critical pathway for degrading misfolded and/or damaged proteins, including the copper-zinc superoxide dismutase (SOD1) mutants linked to familial ALS. We previously reported that p62 interacted with ALS mutants of SOD1 and that the ubiquitin-association domain of p62 was dispensable for the interaction. In this study, we identified two distinct regions of p62 that were essential to its binding to mutant SOD1: the N-terminal Phox and Bem1 (PB1) domain (residues 1-104) and a separate internal region (residues 178-224) termed here as SOD1 mutant interaction region (SMIR). The PB1 domain is required for appropriate oligomeric status of p62 and the SMIR is the actual region interacting with mutant SOD1. Within the SMIR, the conserved W184, H190 and positively charged R183, R186, K187, and K189 residues are critical to the p62-mutant SOD1 interaction as substitution of these residues with alanine resulted in significantly abolished binding. In addition, SMIR and the p62 sequence responsible for the interaction with LC3, a protein essential for autophagy activation, are independent of each other. In cells lacking p62, the existence of mutant SOD1 in acidic autolysosomes decreased, suggesting that p62 can function as an adaptor between mutant SOD1 and the autophagy machinery. This study provides a novel molecular mechanism by which mutant SOD1 can be recognized by p62 in an ubiquitin-independent fashion and targeted for the autophagy-lysosome degradation pathway.
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Affiliation(s)
- Jozsef Gal
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536, USA
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Cheroni C, Marino M, Tortarolo M, Veglianese P, De Biasi S, Fontana E, Zuccarello LV, Maynard CJ, Dantuma NP, Bendotti C. Functional alterations of the ubiquitin-proteasome system in motor neurons of a mouse model of familial amyotrophic lateral sclerosis. Hum Mol Genet 2008; 18:82-96. [PMID: 18826962 DOI: 10.1093/hmg/ddn319] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In familial and sporadic amyotrophic lateral sclerosis (ALS) and in rodent models of the disease, alterations in the ubiquitin-proteasome system (UPS) may be responsible for the accumulation of potentially harmful ubiquitinated proteins, leading to motor neuron death. In the spinal cord of transgenic mice expressing the familial ALS superoxide dismutase 1 (SOD1) gene mutation G93A (SOD1G93A), we found a decrease in constitutive proteasome subunits during disease progression, as assessed by real-time PCR and immunohistochemistry. In parallel, an increased immunoproteasome expression was observed, which correlated with a local inflammatory response due to glial activation. These findings support the existence of proteasome modifications in ALS vulnerable tissues. To functionally investigate the UPS in ALS motor neurons in vivo, we crossed SOD1G93A mice with transgenic mice that express a fluorescently tagged reporter substrate of the UPS. In double-transgenic Ub(G76V)-GFP /SOD1G93A mice an increase in Ub(G76V)-GFP reporter, indicative of UPS impairment, was detectable in a few spinal motor neurons and not in reactive astrocytes or microglia, at symptomatic stage but not before symptoms onset. The levels of reporter transcript were unaltered, suggesting that the accumulation of Ub(G76V)-GFP was due to deficient reporter degradation. In some motor neurons the increase of Ub(G76V)-GFP was accompanied by the accumulation of ubiquitin and phosphorylated neurofilaments, both markers of ALS pathology. These data suggest that UPS impairment occurs in motor neurons of mutant SOD1-linked ALS mice and may play a role in the disease progression.
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Affiliation(s)
- Cristina Cheroni
- Laboratory of Molecular Neurobiology, Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Via La Masa, 19, 20156 Milan, Italy
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Kabashi E, Valdmanis PN, Dion P, Rouleau GA. Oxidized/misfolded superoxide dismutase-1: the cause of all amyotrophic lateral sclerosis? Ann Neurol 2008; 62:553-9. [PMID: 18074357 DOI: 10.1002/ana.21319] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The identification in 1993 of superoxide dismutase-1 (SOD1) mutations as the cause of 10 to 20% of familial amyotrophic lateral sclerosis cases, which represents 1 to 2% of all amyotrophic lateral sclerosis (ALS) cases, prompted a substantial amount of research into the mechanisms of SOD1-mediated toxicity. Recent experiments have demonstrated that oxidation of wild-type SOD1 leads to its misfolding, causing it to gain many of the same toxic properties as mutant SOD1. In vitro studies of oxidized/misfolded SOD1 and in vivo studies of misfolded SOD1 have indicated that these protein species are selectively toxic to motor neurons, suggesting that oxidized/misfolded SOD1 could lead to ALS even in individuals who do not carry an SOD1 mutation. It has also been reported that glial cells secrete oxidized/misfolded mutant SOD1 to the extracellular environment, where it can trigger the selective death of motor neurons, offering a possible explanation for the noncell autonomous nature of mutant SOD1 toxicity and the rapid progression of disease once the first symptoms develop. Therefore, considering that sporadic (SALS) and familial ALS (FALS) cases are clinically indistinguishable, the toxic properties of mutated SOD1 are similar to that of oxidized/misfolded wild-type SOD1 (wtSOD1), and secreted/extracellular misfolded SOD1 is selectively toxic to motor neurons, we propose that oxidized/misfolded SOD1 is the cause of most forms of classic ALS and should be a prime target for the design of ALS treatments.
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Affiliation(s)
- Edor Kabashi
- Centre for Excellence in Neuromics, University of Montreal, the Centre Hospitalier de l'Université de Montreal and Ste-Justine Hospital, Montreal, Quebec, Canada
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Abstract
Mutant superoxide dismutase 1 (mtSOD1) causes dominantly inherited amyotrophic lateral sclerosis (ALS). The mechanism for mtSOD1 toxicity remains unknown. Two main hypotheses are the impairment of proteasomal function and chaperone depletion by misfolded mtSOD1. Here, we employed FRET/FLIM and biosensor imaging to quantitatively localize ubiquitination, as well as chaperone binding of mtSOD1, and to assess their effect on proteasomal and protein folding activities. We found large differences in ubiquitination and chaperone interaction levels for wild-type (wt) SOD1 versus mtSOD1 in intact single cells. Moreover, SOD1 ubiquitination levels differ between proteasomal structures and cytoplasmic material. Hsp70 binding and ubiquitination of wt and mtSOD1 species are highly correlated, demonstrating the coupled upregulation of both cellular detoxification mechanisms upon mtSOD1 expression. Biosensor imaging in single cells revealed that mtSOD1 expression alters cellular protein folding activity but not proteasomal function in the neuronal cell line examined. Our results provide the first cell-by-cell-analysis of SOD1 ubiquitination and chaperone interaction. Moreover, our study opens new methodological avenues for cell biological research on ALS.
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Harrigan JA, Piotrowski J, Di Noto L, Levine RL, Bohr VA. Metal-catalyzed oxidation of the Werner syndrome protein causes loss of catalytic activities and impaired protein-protein interactions. J Biol Chem 2007; 282:36403-11. [PMID: 17911100 DOI: 10.1074/jbc.m706107200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Metal-catalyzed oxidation reactions target amino acids in the metal binding pocket of proteins. Such oxidation reactions generally result in either preferential degradation of the protein or accumulation of a catalytically inactive pool of protein with age. Consistently, levels of oxidized proteins have been shown to increase with age. The segmental, progeroid disorder Werner syndrome results from loss of the Werner syndrome protein (WRN). WRN is a member of the RecQ family of DNA helicases and possesses exonuclease and ATP-dependent helicase activities. Furthermore, each of the helicase and exonuclease domains of WRN contains a metal binding pocket. In this report we examined for metal-catalyzed oxidation of WRN in the presence of iron or copper. We found that WRN was oxidized in vitro by iron but not by copper. Iron-mediated oxidation resulted in the inhibition of both WRN helicase and exonuclease activities. Oxidation of WRN also inhibited binding to several known protein partners. In addition, we did not observe degradation of oxidized WRN by the 20 S proteasome in vitro. Finally, exposure of cells to hydrogen peroxide resulted in oxidation of WRN in vivo. Therefore, our results demonstrate that WRN undergoes metal-catalyzed oxidation in the presence of iron, and iron-mediated oxidation of WRN likely results in the accumulation of a catalytically inactive form of the protein, which may contribute to age-related phenotypes.
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Affiliation(s)
- Jeanine A Harrigan
- Laboratory of Molecular Gerontology, NIA, National Institutes of Health, Baltimore, Maryland 21224, USA
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Niwa JI, Yamada SI, Ishigaki S, Sone J, Takahashi M, Katsuno M, Tanaka F, Doyu M, Sobue G. Disulfide Bond Mediates Aggregation, Toxicity, and Ubiquitylation of Familial Amyotrophic Lateral Sclerosis-linked Mutant SOD1. J Biol Chem 2007; 282:28087-95. [PMID: 17666395 DOI: 10.1074/jbc.m704465200] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in the Cu/Zn-superoxide dismutase (SOD1) gene cause familial amyotrophic lateral sclerosis (ALS) through the gain of a toxic function; however, the nature of this toxic function remains largely unknown. Ubiquitylated aggregates of mutant SOD1 proteins in affected brain lesions are pathological hallmarks of the disease and are suggested to be involved in several proposed mechanisms of motor neuron death. Recent studies suggest that mutant SOD1 readily forms an incorrect disulfide bond upon mild oxidative stress in vitro, and the insoluble SOD1 aggregates in spinal cord of ALS model mice contain multimers cross-linked via intermolecular disulfide bonds. Here we show that a non-physiological intermolecular disulfide bond between cysteines at positions 6 and 111 of mutant SOD1 is important for high molecular weight aggregate formation, ubiquitylation, and neurotoxicity, all of which were dramatically reduced when the pertinent cysteines were replaced in mutant SOD1 expressed in Neuro-2a cells. Dorfin is a ubiquityl ligase that specifically binds familial ALS-linked mutant SOD1 and ubiquitylates it, thereby promoting its degradation. We found that Dorfin ubiquitylated mutant SOD1 by recognizing the Cys(6)- and Cys(111)-disulfide cross-linked form and targeted it for proteasomal degradation.
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Affiliation(s)
- Jun-ichi Niwa
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8500, Japan
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Puttaparthi K, Van Kaer L, Elliott JL. Assessing the role of immuno-proteasomes in a mouse model of familial ALS. Exp Neurol 2007; 206:53-8. [PMID: 17482163 PMCID: PMC2692686 DOI: 10.1016/j.expneurol.2007.03.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2007] [Revised: 03/05/2007] [Accepted: 03/22/2007] [Indexed: 11/23/2022]
Abstract
The accumulation of protein aggregates is thought to be an important component in the pathogenesis of mutant SOD1-induced disease. Mutant SOD1 aggregates appear to be cleared by proteasomes, at least in vitro, suggesting a potentially important role for proteasome degradation pathways in vivo. G93A SOD1 transgenic mice show an increase in proteasome activity and induction of immuno-proteasome subunits within spinal cord as they develop neurological symptoms. To determine what role immuno-proteasomes may have in mutant SOD1-induced disease, we crossed G93A SOD1 transgenic mice with LMP2-/- mice to obtain G93A SOD1 mice lacking the LMP2 immuno-proteasome subunit. G93A SOD1/LMP2-/- mice show significant reductions in proteasome function within spinal cord compared to G93A SOD1 mice. However, G93A SOD1/LMP2-/- mice show no change in motor function decline, or survival compared to G93A SOD1 mice. These results indicate that the loss of immuno-proteasome function in vivo does not significantly alter mutant SOD1-induced disease.
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Affiliation(s)
- Krishna Puttaparthi
- Department of Neurology, University of Texas, Southwestern Medical Center, 5323 Harry Hines BLVD, Dallas, Tx 75390
| | - Luc Van Kaer
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, 1161 21 Avenue South, Nashville, Tn 37232, E-mail: , Phone: 214-645-6242, Fax: 214-645-6238
| | - Jeffrey L. Elliott
- Department of Neurology, University of Texas, Southwestern Medical Center, 5323 Harry Hines BLVD, Dallas, Tx 75390
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Potter SZ, Zhu H, Shaw BF, Rodriguez JA, Doucette PA, Sohn SH, Durazo A, Faull KF, Gralla EB, Nersissian AM, Valentine JS. Binding of a single zinc ion to one subunit of copper-zinc superoxide dismutase apoprotein substantially influences the structure and stability of the entire homodimeric protein. J Am Chem Soc 2007; 129:4575-83. [PMID: 17381088 DOI: 10.1021/ja066690+] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The thermodynamics of zinc binding to metal-free (apo) human and bovine copper-zinc superoxide dismutases (SOD1) were measured using isothermal titration calorimetry. The apparent thermodynamics of zinc binding to the apoproteins were favorable (Ka > 108 M-1), with an observed stoichiometry of one zinc per homodimer. The change in heat capacity for the one-zinc binding event was large and negative (approximately -650 cal mol-1 K-1), suggestive of significant structural changes to the protein upon zinc binding. We further characterized the one-zinc derivative by circular dichroism and determined that this derivative had nearly the same secondary structure as the two-zinc derivative and that both are structurally distinct from the metal-free protein. In addition, we monitored the effect of zinc binding on hydrogen-deuterium exchange and accessibility of histidyl residues to modification by diethyl pyrocarbonate and observed that more than 50% protection was afforded by the binding of one zinc in both assays. Differential scanning calorimetry on the human SOD1 zinc derivatives also showed increased thermostability of the protein due to zinc binding. Further, the melting transitions observed for the one-zinc derivative closely resembled those of the two-zinc derivative. Finally, we observed that the quaternary structure of the protein is stabilized upon binding of one and two zinc ions in analytical ultracentrifugation experiments. Combined, these results suggest communication between the two monomers of SOD1 such that the binding of one zinc ion per homodimer has a more profound effect on the homodimeric protein structure than the binding of subsequent metal ions. The relevance of these findings to amyotrophic lateral sclerosis is discussed.
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Affiliation(s)
- Soshanna Zittin Potter
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095, USA
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Kabashi E, Durham HD. Failure of protein quality control in amyotrophic lateral sclerosis. Biochim Biophys Acta Mol Basis Dis 2006; 1762:1038-50. [PMID: 16876390 DOI: 10.1016/j.bbadis.2006.06.006] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2006] [Revised: 06/06/2006] [Accepted: 06/08/2006] [Indexed: 11/21/2022]
Abstract
The protein chaperoning and ubiquitin-proteasome systems perform many homeostatic functions within cells involving protein folding, transport and degradation. Of paramount importance is ridding cells of mutant or post-translationally modified proteins that otherwise tend to aggregate into insoluble complexes and form inclusions. Such inclusions are characteristic of many neurodegenerative diseases and implicate protein misfolding and aggregation as common aspects of pathogenesis. In the most common familial form of ALS, mutations in SOD1 promote misfolding of the protein and target it for degradation by proteasomes. Although proteasomes can degrade the mutant proteins efficiently, altered solubility and aggregation of mutant SOD1 are features of the disease and occur most prominently in the most vulnerable cells and tissues. Indeed, lumbar spinal cord of mutant SOD1 transgenic mice show early reduction in their capacity for protein chaperoning and proteasome-mediated hydrolysis of substrates, and motor neurons are particularly vulnerable to aggregation of mutant SOD1. A high threshold for upregulating key pathways in response to the stress of added substrate load may contribute to this vulnerability. The broad spectrum neuroprotective capability and efficacy of some chaperone-based therapies in preclinical models makes these pathways attractive as targets for therapy in ALS, as well as other neurodegenerative diseases. A better understanding of the mechanisms governing the regulation of protein chaperones and UPS components would facilitate development of treatments that upregulate these pathways in a coordinated manner in neural tissue without long term toxicity.
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Affiliation(s)
- Edor Kabashi
- Department of Neurology/Neurosurgery and Montreal Neurological Institute, McGill University, 3801 University St., Montreal QC, Canada H3A 2B4
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Halliwell B. Proteasomal dysfunction: a common feature of neurodegenerative diseases? Implications for the environmental origins of neurodegeneration. Antioxid Redox Signal 2006; 8:2007-19. [PMID: 17034346 DOI: 10.1089/ars.2006.8.2007] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The neurodegenerative diseases that afflict humans affect different part of the nervous system and have different symptoms and prognoses, yet they have certain things in common. One of them is defects in the clearance of abnormal or other "unwanted" proteins, particularly affecting the proteasome system. In this review, I advance two concepts: (a) that defects in protein clearance can be a fundamental cause of neurodegeneration, and (b) that because proteasome inhibitors are widespread in nature, their ingestion may contribute to "spontaneous" neurodegeneration.
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Affiliation(s)
- B Halliwell
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
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Kabuta T, Suzuki Y, Wada K. Degradation of Amyotrophic Lateral Sclerosis-linked Mutant Cu,Zn-Superoxide Dismutase Proteins by Macroautophagy and the Proteasome. J Biol Chem 2006; 281:30524-33. [PMID: 16920710 DOI: 10.1074/jbc.m603337200] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in the Cu,Zn-superoxide dismutase (SOD1) gene cause approximately 20% of familial cases of amyotrophic lateral sclerosis (fALS). Accumulating evidence indicates that a gain of toxic function of mutant SOD1 proteins is the cause of the disease. It has also been shown that the ubiquitin-proteasome pathway plays a role in the clearance and toxicity of mutant SOD1. In this study, we investigated the degradation pathways of wild-type and mutant SOD1 in neuronal and nonneuronal cells. We provide here the first evidence that wild-type and mutant SOD1 are degraded by macroautophagy as well as by the proteasome. Based on experiments with inhibitors of these degradation pathways, the contribution of macroautophagy to mutant SOD1 clearance is comparable with that of the proteasome pathway. Using assays that measure cell viability and cell death, we observed that under conditions where expression of mutant SOD1 alone does not induce toxicity, macroautophagy inhibition induced mutant SOD1-mediated cell death, indicating that macroautophagy reduces the toxicity of mutant SOD1 proteins. We therefore propose that both macroautophagy and the proteasome are important for the reduction of mutant SOD1-mediated neurotoxicity in fALS. Inhibition of macroautophagy also increased SOD1 levels in detergent-soluble and -insoluble fractions, suggesting that both detergent-soluble and -insoluble SOD1 are degraded by macroautophagy. These findings may provide further insights into the mechanisms of pathogenesis of fALS.
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Affiliation(s)
- Tomohiro Kabuta
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo 187-8502, Japan
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Basso M, Massignan T, Samengo G, Cheroni C, De Biasi S, Salmona M, Bendotti C, Bonetto V. Insoluble mutant SOD1 is partly oligoubiquitinated in amyotrophic lateral sclerosis mice. J Biol Chem 2006; 281:33325-35. [PMID: 16943203 DOI: 10.1074/jbc.m603489200] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in the Cu,Zn-superoxide dismutase (SOD1) gene cause a familial form of amyotrophic lateral sclerosis (ALS) through an unknown gain-of-function mechanism. Mutant SOD1 aggregation may be the toxic property. In fact, proteinaceous inclusions rich in mutant SOD1 have been found in tissues from the familial form of ALS patients and in mutant SOD1 animals, before disease onset. However, very little is known of the constituents and mechanism of formation of aggregates in ALS. We and others have shown that there is a progressive accumulation of detergent-insoluble mutant SOD1 in the spinal cord of G93A SOD1 mice. To investigate the mechanism of SOD1 aggregation, we characterized by proteome technologies SOD1 isoforms in a Triton X-100-insoluble fraction of spinal cord from G93A SOD1 mice at different stages of the disease. This showed that at symptomatic stages of the disease, part of the insoluble SOD1 is unambiguously mono- and oligoubiquitinated, in spinal cord and not in hippocampus, and that ubiquitin branches at Lys(48), the major signal for proteasome degradation. At presymptomatic stages of the disease, only insoluble unmodified SOD1 is recovered. Partial ubiquitination of SOD1-rich inclusions was also confirmed by immunohistochemical and electron microscopy analysis of lumbar spinal cord sections from symptomatic G93A SOD1 mice. On the basis of these results, we propose that ubiquitination occurs only after SOD1 aggregation and that oligoubiquitination may underline alternative mechanisms in disease pathogenesis.
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Carroll MC, Outten CE, Proescher JB, Rosenfeld L, Watson WH, Whitson LJ, Hart PJ, Jensen LT, Culotta VC. The effects of glutaredoxin and copper activation pathways on the disulfide and stability of Cu,Zn superoxide dismutase. J Biol Chem 2006; 281:28648-56. [PMID: 16880213 PMCID: PMC2757158 DOI: 10.1074/jbc.m600138200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in Cu,Zn superoxide dismutase (SOD1) can cause amyotrophic lateral sclerosis (ALS) through mechanisms proposed to involve SOD1 misfolding, but the intracellular factors that modulate folding and stability of SOD1 are largely unknown. By using yeast and mammalian expression systems, we demonstrate here that SOD1 stability is governed by post-translational modification factors that target the SOD1 disulfide. Oxidation of the human SOD1 disulfide in vivo was found to involve both the copper chaperone for SOD1 (CCS) and the CCS-independent pathway for copper activation. When both copper pathways were blocked, wild type SOD1 stably accumulated in yeast cells with a reduced disulfide, whereas ALS SOD1 mutants A4V, G93A, and G37R were degraded. We describe here an unprecedented role for the thiol oxidoreductase glutaredoxin in reducing the SOD1 disulfide and destabilizing ALS mutants. Specifically, the major cytosolic glutaredoxin of yeast was seen to reduce the intramolecular disulfide of ALS SOD1 mutant A4V SOD1 in vivo and in vitro. By comparison, glutaredoxin was less reactive toward the disulfide of wild type SOD1. The apo-form of A4V SOD1 was highly reactive with glutaredoxin but not SOD1 containing both copper and zinc. Glutaredoxin therefore preferentially targets the immature form of ALS mutant SOD1 lacking metal co-factors. Overall, these studies implicate a critical balance between cellular reductants such as glutaredoxin and copper activation pathways in controlling the disulfide and stability of SOD1 in vivo.
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Affiliation(s)
- Mark C. Carroll
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Caryn E. Outten
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Jody B. Proescher
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Leah Rosenfeld
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Walter H. Watson
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Lisa J. Whitson
- Department of Biochemistry and the X-ray Crystallography Core Laboratory, the University of Texas Health Science Center, San Antonio, Texas 78229
| | - P. John Hart
- Department of Biochemistry and the X-ray Crystallography Core Laboratory, the University of Texas Health Science Center, San Antonio, Texas 78229
- Geriatric Research, Education, and Clinical Center, Department of Veterans Affairs, South Texas Veterans Health Care System, the University of Texas Health Science Center, San Antonio, Texas 78229
| | - Laran T. Jensen
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Valeria Cizewski Culotta
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
- To whom correspondence should be addressed: Dept. of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe St., Rm. E7626, Baltimore, MD 21205. Tel.: 410-955-3029; Fax: 410-955-0116;
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Hart PJ. Pathogenic superoxide dismutase structure, folding, aggregation and turnover. Curr Opin Chem Biol 2006; 10:131-8. [PMID: 16516535 DOI: 10.1016/j.cbpa.2006.02.034] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2005] [Accepted: 02/22/2006] [Indexed: 11/25/2022]
Abstract
Significant advances have been made during the past two years toward an understanding of the molecular basis for how mutations in human cytosolic copper-zinc superoxide dismutase (SOD1) cause the inherited form of amyotrophic lateral sclerosis (ALS). Biophysical studies suggest that the pathogenic mutations destabilize loop or beta-barrel structural elements of the protein. With few exceptions, the loss of metal ions and reduction of the intrasubunit disulfide bond enhance this destabilization. In mouse models of the disease, the formation of visible aggregates containing mutant SOD1 occurs relatively late in the lifespan, hinting that the quality control and protein turnover systems of motor neurons eventually become overwhelmed or compromised. Studies probing SOD1 turnover have suggested the possibility that proteolytic breakdown products may play a role in pathogenesis.
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Affiliation(s)
- P John Hart
- Department of Biochemistry, Department of Veterans Affairs, South Texas Veterans Health Care System, The University of Texas Health Science Center at San Antonio, 78229-3900, USA.
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