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Shafiq M, Da Vela S, Amin L, Younas N, Harris DA, Zerr I, Altmeppen HC, Svergun D, Glatzel M. The prion protein and its ligands: Insights into structure-function relationships. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119240. [PMID: 35192891 DOI: 10.1016/j.bbamcr.2022.119240] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 01/23/2022] [Accepted: 01/28/2022] [Indexed: 06/14/2023]
Abstract
The prion protein is a multifunctional protein that exists in at least two different folding states. It is subject to diverse proteolytic processing steps that lead to prion protein fragments some of which are membrane-bound whereas others are soluble. A multitude of ligands bind to the prion protein and besides proteinaceous binding partners, interaction with metal ions and nucleic acids occurs. Although of great importance, information on structural and functional consequences of prion protein binding to its partners is limited. Here, we will reflect on the structure-function relationship of the prion protein and its binding partners considering the different folding states and prion protein fragments.
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Affiliation(s)
- Mohsin Shafiq
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20251 Hamburg, Germany
| | - Stefano Da Vela
- European Molecular Biology Laboratory (EMBL), Hamburg c/o German Electron Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany
| | - Ladan Amin
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, United States
| | - Neelam Younas
- Department of Neurology, University Medical Center Goettingen, Robert-Koch-str. 40, 37075 Goettingen, Germany
| | - David A Harris
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, United States
| | - Inga Zerr
- Department of Neurology, University Medical Center Goettingen, Robert-Koch-str. 40, 37075 Goettingen, Germany
| | - Hermann C Altmeppen
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20251 Hamburg, Germany
| | - Dmitri Svergun
- European Molecular Biology Laboratory (EMBL), Hamburg c/o German Electron Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany
| | - Markus Glatzel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20251 Hamburg, Germany.
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Harischandra DS, Ghaisas S, Zenitsky G, Jin H, Kanthasamy A, Anantharam V, Kanthasamy AG. Manganese-Induced Neurotoxicity: New Insights Into the Triad of Protein Misfolding, Mitochondrial Impairment, and Neuroinflammation. Front Neurosci 2019; 13:654. [PMID: 31293375 PMCID: PMC6606738 DOI: 10.3389/fnins.2019.00654] [Citation(s) in RCA: 136] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 06/06/2019] [Indexed: 12/21/2022] Open
Abstract
Occupational or environmental exposure to manganese (Mn) can lead to the development of "Manganism," a neurological condition showing certain motor symptoms similar to Parkinson's disease (PD). Like PD, Mn toxicity is seen in the central nervous system mainly affecting nigrostriatal neuronal circuitry and subsequent behavioral and motor impairments. Since the first report of Mn-induced toxicity in 1837, various experimental and epidemiological studies have been conducted to understand this disorder. While early investigations focused on the impact of high concentrations of Mn on the mitochondria and subsequent oxidative stress, current studies have attempted to elucidate the cellular and molecular pathways involved in Mn toxicity. In fact, recent reports suggest the involvement of Mn in the misfolding of proteins such as α-synuclein and amyloid, thus providing credence to the theory that environmental exposure to toxicants can either initiate or propagate neurodegenerative processes by interfering with disease-specific proteins. Besides manganism and PD, Mn has also been implicated in other neurological diseases such as Huntington's and prion diseases. While many reviews have focused on Mn homeostasis, the aim of this review is to concisely synthesize what we know about its effect primarily on the nervous system with respect to its role in protein misfolding, mitochondrial dysfunction, and consequently, neuroinflammation and neurodegeneration. Based on the current evidence, we propose a 'Mn Mechanistic Neurotoxic Triad' comprising (1) mitochondrial dysfunction and oxidative stress, (2) protein trafficking and misfolding, and (3) neuroinflammation.
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Affiliation(s)
- Dilshan S Harischandra
- Department of Biomedical Sciences, Parkinson's Disorder Research Laboratory, Iowa State University, Ames, IA, United States
| | - Shivani Ghaisas
- Department of Biomedical Sciences, Parkinson's Disorder Research Laboratory, Iowa State University, Ames, IA, United States
| | - Gary Zenitsky
- Department of Biomedical Sciences, Parkinson's Disorder Research Laboratory, Iowa State University, Ames, IA, United States
| | - Huajun Jin
- Department of Biomedical Sciences, Parkinson's Disorder Research Laboratory, Iowa State University, Ames, IA, United States
| | - Arthi Kanthasamy
- Department of Biomedical Sciences, Parkinson's Disorder Research Laboratory, Iowa State University, Ames, IA, United States
| | - Vellareddy Anantharam
- Department of Biomedical Sciences, Parkinson's Disorder Research Laboratory, Iowa State University, Ames, IA, United States
| | - Anumantha G Kanthasamy
- Department of Biomedical Sciences, Parkinson's Disorder Research Laboratory, Iowa State University, Ames, IA, United States
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Kondru N, Manne S, Greenlee J, West Greenlee H, Anantharam V, Halbur P, Kanthasamy A, Kanthasamy A. Integrated Organotypic Slice Cultures and RT-QuIC (OSCAR) Assay: Implications for Translational Discovery in Protein Misfolding Diseases. Sci Rep 2017; 7:43155. [PMID: 28233859 PMCID: PMC5324099 DOI: 10.1038/srep43155] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 01/19/2017] [Indexed: 01/13/2023] Open
Abstract
Protein misfolding is a key pathological event in neurodegenerative diseases like prion diseases, synucleinopathies, and tauopathies that are collectively termed protein misfolding disorders. Prions are a prototypic model to study protein aggregation biology and therapeutic development. Attempts to develop anti-prion therapeutics have been impeded by the lack of screening models that faithfully replicate prion diseases and the lack of rapid, sensitive biological screening systems. Therefore, a sensitive model encompassing prion replication and neurotoxicity would be indispensable to the pursuit of intervention strategies. We present an ultra-sensitive screening system coupled to an ex vivo prion organotypic slice culture model to rapidly advance rationale-based high-throughput therapeutic strategies. This hybrid Organotypic Slice Culture Assay coupled with RT-QuIC (OSCAR) permits sensitive, specific and quantitative detection of prions from an infectious slice culture model on a reduced time scale. We demonstrate that the anti-prion activity of test compounds can be readily resolved based on the power and kinetics of seeding activity in the OSCAR screening platform and that the prions generated in slice cultures are biologically active. Collectively, our results imply that OSCAR is a robust model of prion diseases that offers a promising platform for understanding prion proteinopathies and advancing anti-prion therapeutics.
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Affiliation(s)
- Naveen Kondru
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Sireesha Manne
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Justin Greenlee
- Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA 50011, USA
| | - Heather West Greenlee
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Vellareddy Anantharam
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Patrick Halbur
- Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Arthi Kanthasamy
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Anumantha Kanthasamy
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
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Kim DS, Jin H, Anantharam V, Gordon R, Kanthasamy A, Kanthasamy AG. p73 gene in dopaminergic neurons is highly susceptible to manganese neurotoxicity. Neurotoxicology 2016; 59:231-239. [PMID: 27107493 DOI: 10.1016/j.neuro.2016.04.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 04/18/2016] [Accepted: 04/18/2016] [Indexed: 12/21/2022]
Abstract
Chronic exposure to elevated levels of manganese (Mn) has been linked to a Parkinsonian-like movement disorder, resulting from dysfunction of the extrapyramidal motor system within the basal ganglia. However, the exact cellular and molecular mechanisms of Mn-induced neurotoxicity remain elusive. In this study, we treated C57BL/6J mice with 30mg/kg Mn via oral gavage for 30 days. Interestingly, in nigral tissues of Mn-exposed mice, we found a significant downregulation of the truncated isoform of p73 protein at the N-terminus (ΔNp73). To further determine the functional role of Mn-induced p73 downregulation in Mn neurotoxicity, we examined the interrelationship between the effect of Mn on p73 gene expression and apoptotic cell death in an N27 dopaminergic neuronal model. Consistent with our animal study, 300μM Mn treatment significantly suppressed p73 mRNA expression in N27 dopaminergic cells. We further determined that protein levels of the ΔNp73 isoform was also reduced in Mn-treated N27 cells and primary striatal cultures. Furthermore, overexpression of ΔNp73 conferred modest cellular protection against Mn-induced neurotoxicity. Taken together, our results demonstrate that Mn exposure downregulates p73 gene expression resulting in enhanced susceptibility to apoptotic cell death. Thus, further characterization of the cellular mechanism underlying p73 gene downregulation will improve our understanding of the molecular underpinnings of Mn neurotoxicity.
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Affiliation(s)
- Dong-Suk Kim
- Parkinson's Disorder Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
| | - Huajun Jin
- Parkinson's Disorder Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
| | - Vellareddy Anantharam
- Parkinson's Disorder Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
| | - Richard Gordon
- Parkinson's Disorder Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
| | - Arthi Kanthasamy
- Parkinson's Disorder Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
| | - Anumantha G Kanthasamy
- Parkinson's Disorder Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States.
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Adam P, Křížková S, Heger Z, Babula P, Pekařík V, Vaculovičoá M, Gomes CM, Kizek R, Adam V. Metallothioneins in Prion- and Amyloid-Related Diseases. J Alzheimers Dis 2016; 51:637-56. [DOI: 10.3233/jad-150984] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Pavlína Adam
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, Brno, Czech Republic
- Central European Institute of Technology, Brno University of Technology, Technicka, Brno, Czech Republic
| | - Soňa Křížková
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, Brno, Czech Republic
- Central European Institute of Technology, Brno University of Technology, Technicka, Brno, Czech Republic
| | - Zbyněk Heger
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, Brno, Czech Republic
- Central European Institute of Technology, Brno University of Technology, Technicka, Brno, Czech Republic
| | - Petr Babula
- Department of Physiology, Faculty of Medicine, Masaryk University, Kamenice, Brno, Czech Republic
| | - Vladimír Pekařík
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, Brno, Czech Republic
- Central European Institute of Technology, Brno University of Technology, Technicka, Brno, Czech Republic
| | - Markéta Vaculovičoá
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, Brno, Czech Republic
- Central European Institute of Technology, Brno University of Technology, Technicka, Brno, Czech Republic
| | - Cláudio M. Gomes
- Faculdade de Ciências Universidade de Lisboa, Biosystems and Integrative Sciences Institute and Department of Chemistry and Biochemistry, Universidade de Lisboa, Campo Grande, Lisboa, Portugal
| | - René Kizek
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, Brno, Czech Republic
- Central European Institute of Technology, Brno University of Technology, Technicka, Brno, Czech Republic
| | - Vojtěch Adam
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, Brno, Czech Republic
- Central European Institute of Technology, Brno University of Technology, Technicka, Brno, Czech Republic
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Tripathi AK, Haldar S, Qian J, Beserra A, Suda S, Singh A, Hopfer U, Chen SG, Garrick MD, Turner JR, Knutson MD, Singh N. Prion protein functions as a ferrireductase partner for ZIP14 and DMT1. Free Radic Biol Med 2015; 84:322-330. [PMID: 25862412 PMCID: PMC4476631 DOI: 10.1016/j.freeradbiomed.2015.03.037] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 03/30/2015] [Accepted: 03/30/2015] [Indexed: 12/21/2022]
Abstract
Excess circulating iron is stored in the liver, and requires reduction of non-Tf-bound iron (NTBI) and transferrin (Tf) iron at the plasma membrane and endosomes, respectively, by ferrireductase (FR) proteins for transport across biological membranes through divalent metal transporters. Here, we report that prion protein (PrP(C)), a ubiquitously expressed glycoprotein most abundant on neuronal cells, functions as a FR partner for divalent-metal transporter-1 (DMT1) and ZIP14. Thus, absence of PrP(C) in PrP-knock-out (PrP(-/-)) mice resulted in markedly reduced liver iron stores, a deficiency that was not corrected by chronic or acute administration of iron by the oral or intraperitoneal routes. Likewise, preferential radiolabeling of circulating NTBI with (59)Fe revealed significantly reduced uptake and storage of NTBI by the liver of PrP(-/-) mice relative to matched PrP(+/+) controls. However, uptake, storage, and utilization of ferritin-bound iron that does not require reduction for uptake were increased in PrP(-/-) mice, indicating a compensatory response to the iron deficiency. Expression of exogenous PrP(C) in HepG2 cells increased uptake and storage of ferric iron (Fe(3+)), not ferrous iron (Fe(2+)), from the medium, supporting the function of PrP(C) as a plasma membrane FR. Coexpression of PrP(C) with ZIP14 and DMT1 in HepG2 cells increased uptake of Fe(3+) significantly, and surprisingly, increased the ratio of N-terminally truncated PrP(C) forms lacking the FR domain relative to full-length PrP(C). Together, these observations indicate that PrP(C) promotes, and possibly regulates, the uptake of NTBI through DMT1 and Zip14 via its FR activity. Implications of these observations for neuronal iron homeostasis under physiological and pathological conditions are discussed.
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Affiliation(s)
- Ajai K. Tripathi
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Swati Haldar
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Juan Qian
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Amber Beserra
- School of Arts and Sciences, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Srinivas Suda
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Ajay Singh
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Ulrich Hopfer
- Department of physiology and Biophysics, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Shu G. Chen
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | | | | | | | - Neena Singh
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
- To whom correspondence should be addressed: Neena Singh, Department of Pathology, Case Western Reserve University, 2103 Cornell Road, Cleveland, Ohio 44106, USA. Tel: 216-368-2617;
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Harischandra DS, Kondru N, Martin DP, Kanthasamy A, Jin H, Anantharam V, Kanthasamy AG. Role of proteolytic activation of protein kinase Cδ in the pathogenesis of prion disease. Prion 2015; 8:143-53. [PMID: 24576946 DOI: 10.4161/pri.28369] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Prion diseases are infectious and inevitably fatal neurodegenerative diseases characterized by prion replication, widespread protein aggregation and spongiform degeneration of major brain regions controlling motor function. Oxidative stress has been implicated in prion-related neuronal degeneration, but the molecular mechanisms underlying prion-induced oxidative damage are not well understood. In this study, we evaluated the role of oxidative stress-sensitive, pro-apoptotic protein kinase Cδ (PKCδ) in prion-induced neuronal cell death using cerebellar organotypic slice cultures (COSC) and mouse models of prion diseases. We found a significant upregulation of PKCδ in RML scrapie-infected COSC, as evidenced by increased levels of both PKCδ protein and its mRNA. We also found an enhanced regulatory phosphorylation of PKCδ at its two regulatory sites, Thr505 in the activation loop and Tyr311 at the caspase-3 cleavage site. The prion infection also induced proteolytic activation of PKCδ in our COSC model. Immunohistochemical analysis of scrapie-infected COSC revealed loss of PKCδ positive Purkinje cells and enhanced astrocyte proliferation. Further examination of PKCδ signaling in the RML scrapie adopted in vivo mouse model showed increased proteolytic cleavage and Tyr 311 phosphorylation of the kinase. Notably, we observed a delayed onset of scrapie-induced motor symptoms in PKCδ knockout (PKCδ(-/-)) mice as compared with wild-type (PKCδ(+/+)) mice, further substantiating the role of PKCδ in prion disease. Collectively, these data suggest that PKCδ signaling likely plays a role in the neurodegenerative processes associated with prion diseases.
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Harischandra DS, Jin H, Anantharam V, Kanthasamy A, Kanthasamy AG. α-Synuclein protects against manganese neurotoxic insult during the early stages of exposure in a dopaminergic cell model of Parkinson's disease. Toxicol Sci 2014; 143:454-68. [PMID: 25416158 DOI: 10.1093/toxsci/kfu247] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The pathological role of α-synuclein (α-Syn) aggregation in neurodegeneration is well recognized, but the physiological function of normal α-Syn remains unknown. As α-Syn protein contains multiple divalent metal binding sites, herein we conducted a comprehensive characterization of the role of α-Syn in manganese-induced dopaminergic neurotoxicity. We established transgenic N27 dopaminergic neuronal cells by stably expressing human wild-type α-Syn at normal physiological levels. α-Syn-expressing dopaminergic cells significantly attenuated Mn-induced neurotoxicity for 24-h exposures relative to vector control cells. To further explore cellular mechanisms, we studied the mitochondria-dependent apoptotic pathway. Analysis of a key mitochondrial apoptotic initiator, cytochrome c, revealed that α-Syn significantly reduces the Mn-induced cytochrome c release into cytosol. The downstream caspase cascade, involving caspase-9 and caspase-3 activation, during Mn exposure was also largely attenuated in Mn-treated α-Syn cells in a time-dependent manner. α-Syn cells also showed a dramatic reduction in the Mn-induced proteolytic activation of the pro-apoptotic kinase PKCδ. The generation of Mn-induced reactive oxygen species (ROS) did not differ between α-Syn and vector control cells, indicating that α-Syn exerts its protective effect independent of altering ROS generation. Inductively coupled plasma-mass spectrometry (ICP-MS) revealed no significant differences in intracellular Mn levels between treated vector and α-Syn cells. Notably, the expression of wild-type α-Syn in primary mesencephalic cells also rescued cells from Mn-induced neurotoxicity. However, prolonged exposure to Mn promoted protein aggregation in α-Syn-expressing cells. Collectively, these results demonstrate that wild-type α-Syn exhibits neuroprotective effects against Mn-induced neurotoxicity during the early stages of exposure in a dopaminergic neuronal model of PD.
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Affiliation(s)
- Dilshan S Harischandra
- Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University, Ames, Iowa 50011
| | - Huajun Jin
- Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University, Ames, Iowa 50011
| | - Vellareddy Anantharam
- Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University, Ames, Iowa 50011
| | - Arthi Kanthasamy
- Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University, Ames, Iowa 50011
| | - Anumantha G Kanthasamy
- Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University, Ames, Iowa 50011
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9
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Asaithambi A, Ay M, Jin H, Gosh A, Anantharam V, Kanthasamy A, Kanthasamy AG. Protein kinase D1 (PKD1) phosphorylation promotes dopaminergic neuronal survival during 6-OHDA-induced oxidative stress. PLoS One 2014; 9:e96947. [PMID: 24806360 PMCID: PMC4013052 DOI: 10.1371/journal.pone.0096947] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 04/12/2014] [Indexed: 12/20/2022] Open
Abstract
Oxidative stress is a major pathophysiological mediator of degenerative processes in many neurodegenerative diseases including Parkinson’s disease (PD). Aberrant cell signaling governed by protein phosphorylation has been linked to oxidative damage of dopaminergic neurons in PD. Although several studies have associated activation of certain protein kinases with apoptotic cell death in PD, very little is known about protein kinase regulation of cell survival and protection against oxidative damage and degeneration in dopaminergic neurons. Here, we characterized the PKD1-mediated protective pathway against oxidative damage in cell culture models of PD. Dopaminergic neurotoxicant 6-hydroxy dopamine (6-OHDA) was used to induce oxidative stress in the N27 dopaminergic cell model and in primary mesencephalic neurons. Our results indicated that 6-OHDA induced the PKD1 activation loop (PKD1S744/S748) phosphorylation during early stages of oxidative stress and that PKD1 activation preceded cell death. We also found that 6-OHDA rapidly increased phosphorylation of the C-terminal S916 in PKD1, which is required for PKD1 activation loop (PKD1S744/748) phosphorylation. Interestingly, negative modulation of PKD1 activation by RNAi knockdown or by the pharmacological inhibition of PKD1 by kbNB-14270 augmented 6-OHDA-induced apoptosis, while positive modulation of PKD1 by the overexpression of full length PKD1 (PKD1WT) or constitutively active PKD1 (PKD1S744E/S748E) attenuated 6-OHDA-induced apoptosis, suggesting an anti-apoptotic role for PKD1 during oxidative neuronal injury. Collectively, our results demonstrate that PKD1 signaling plays a cell survival role during early stages of oxidative stress in dopaminergic neurons and therefore, positive modulation of the PKD1-mediated signal transduction pathway can provide a novel neuroprotective strategy against PD.
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Affiliation(s)
- Arunkumar Asaithambi
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Muhammet Ay
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Huajun Jin
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Anamitra Gosh
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Vellareddy Anantharam
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Arthi Kanthasamy
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Anumantha G. Kanthasamy
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
- * E-mail:
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Brazier MW, Wedd AG, Collins SJ. Antioxidant and Metal Chelation-Based Therapies in the Treatment of Prion Disease. Antioxidants (Basel) 2014; 3:288-308. [PMID: 26784872 PMCID: PMC4665489 DOI: 10.3390/antiox3020288] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 02/13/2014] [Accepted: 02/28/2014] [Indexed: 12/31/2022] Open
Abstract
Many neurodegenerative disorders involve the accumulation of multimeric assemblies and amyloid derived from misfolded conformers of constitutively expressed proteins. In addition, the brains of patients and experimental animals afflicted with prion disease display evidence of heightened oxidative stress and damage, as well as disturbances to transition metal homeostasis. Utilising a variety of disease model paradigms, many laboratories have demonstrated that copper can act as a cofactor in the antioxidant activity displayed by the prion protein while manganese has been implicated in the generation and stabilisation of disease-associated conformers. This and other evidence has led several groups to test dietary and chelation therapy-based regimens to manipulate brain metal concentrations in attempts to influence the progression of prion disease in experimental mice. Results have been inconsistent. This review examines published data on transition metal dyshomeostasis, free radical generation and subsequent oxidative damage in the pathogenesis of prion disease. It also comments on the efficacy of trialed therapeutics chosen to combat such deleterious changes.
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Affiliation(s)
- Marcus W Brazier
- Department of Pathology, University of Melbourne, Parkville, VIC 3010, Australia.
| | - Anthony G Wedd
- The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia.
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia.
| | - Steven J Collins
- Department of Pathology, University of Melbourne, Parkville, VIC 3010, Australia.
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Kanthasamy AG, Choi C, Jin H, Harischandra DS, Anantharam V, Kanthasamy A. Effect of divalent metals on the neuronal proteasomal system, prion protein ubiquitination and aggregation. Toxicol Lett 2012; 214:288-95. [PMID: 22995398 DOI: 10.1016/j.toxlet.2012.09.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 09/10/2012] [Accepted: 09/11/2012] [Indexed: 10/27/2022]
Abstract
The role of normal cellular prion protein (PrP) remains to be fully elucidated; however, the protein is crucial for the infection and progression of prion diseases. Recent evidence indicates that PrP is a metalloprotein since the octapeptide repeat sequences in the protein have high affinity for various divalent cations and the binding sites appear to play a role in the pathogenesis of prion diseases. In our present study, we tested several divalent metals including manganese and cadmium and determined their effects on protein degradation and protein aggregation in mouse neuronal cells expressing PrP. Cadmium was more neurotoxic than manganese following 24h exposure. Manganese did not show any significant effect on the inhibition of proteasomal activity or formation of high molecular weight ubiquitinated PrPs. Interestingly, treatment with cadmium profoundly inhibited proteasomal activity, which resulted in greatly increased formation of high molecular weight ubiquitinated PrPs. Immunohistochemical analysis also revealed a dramatic increase in formation of oligomers after cadmium treatment. Cadmium also increased the formation of ubiquitinated PrP, but it did not lead to the formation of proteinase-K resistant PrP. Collectively, our results show that a divalent metal, cadmium affects proteasomal function and PrP aggregation, which promote neurotoxicity.
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Affiliation(s)
- A G Kanthasamy
- Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University, Ames, IA 50011, USA.
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12
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Singh A, Qing L, Kong Q, Singh N. Change in the characteristics of ferritin induces iron imbalance in prion disease affected brains. Neurobiol Dis 2012; 45:930-8. [PMID: 22182691 PMCID: PMC3286598 DOI: 10.1016/j.nbd.2011.12.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 10/20/2011] [Accepted: 12/04/2011] [Indexed: 01/28/2023] Open
Abstract
Prion disease associated neurotoxicity is mainly attributed to PrP-scrapie (PrP(Sc)), the disease associated isoform of a normal protein, the prion protein (PrP(C)). Participation of other proteins and processes is suspected, but their identity and contribution to the pathogenic process is unclear. Emerging evidence implicates imbalance of brain iron homeostasis as a significant cause of prion disease-associated neurotoxicity. The underlying cause of this change, however, remains unclear. We demonstrate that iron is sequestered in heat and SDS-stable protein complexes in sporadic-Creutzfeldt-Jakob-disease (sCJD) brains, creating a phenotype of iron deficiency. The underlying cause is change in the characteristics of ferritin, an iron storage protein that becomes aggregated, detergent-insoluble, and partitions with denatured ferritin using conventional methods of ferritin purification. A similar phenotype of iron deficiency is noted in the lumbar spinal cord (SC) tissue of scrapie infected hamsters, a site unlikely to be affected by massive neuronal death and non-specific iron deposition. As a result, the iron uptake protein transferrin (Tf) is upregulated in scrapie infected SC tissue, and increases with disease progression. A direct correlation between Tf and PrP(Sc) suggests sequestration of iron in dysfunctional ferritin that either co-aggregates with PrP(Sc) or is rendered dysfunctional by PrP(Sc) through an indirect process. Surprisingly, amplification of PrP(Sc)in vitro by the protein-misfolding-cyclic-amplification (PMCA) reaction using normal brain homogenate as substrate does not increase the heat and SDS-stable pool of iron even though both PrP(Sc) and ferritin aggregate by this procedure. These observations highlight important differences between PrP(Sc)-protein complexes generated in vivo during disease progression and in vitro by the PMCA reaction, and the significance of these complexes in PrP(Sc)-associated neurotoxicity.
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Affiliation(s)
- Ajay Singh
- Departments of Pathology and Neurology, Case Western Reserve University, 2103 Cornell Road, Cleveland, Ohio 44106
| | - Liuting Qing
- Departments of Pathology and Neurology, Case Western Reserve University, 2103 Cornell Road, Cleveland, Ohio 44106
| | - Qingzhong Kong
- Departments of Pathology and Neurology, Case Western Reserve University, 2103 Cornell Road, Cleveland, Ohio 44106
| | - Neena Singh
- Departments of Pathology and Neurology, Case Western Reserve University, 2103 Cornell Road, Cleveland, Ohio 44106
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Regulation of brain iron and copper homeostasis by brain barrier systems: implication in neurodegenerative diseases. Pharmacol Ther 2011; 133:177-88. [PMID: 22115751 DOI: 10.1016/j.pharmthera.2011.10.006] [Citation(s) in RCA: 198] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Accepted: 10/27/2011] [Indexed: 12/21/2022]
Abstract
Iron (Fe) and copper (Cu) are essential to neuronal function; excess or deficiency of either is known to underlie the pathoetiology of several commonly known neurodegenerative disorders. This delicate balance of Fe and Cu in the central milieu is maintained by the brain barrier systems, i.e., the blood-brain barrier (BBB) between the blood and brain interstitial fluid and the blood-cerebrospinal fluid barrier (BCB) between the blood and cerebrospinal fluid (CSF). This review provides a concise description on the structural and functional characteristics of the brain barrier systems. Current understanding of Fe and Cu transport across the brain barriers is thoroughly examined, with major focuses on whether the BBB and BCB coordinate the direction of Fe and Cu fluxes between the blood and brain/CSF. In particular, the mechanism by which pertinent metal transporters in the barriers, such as the transferrin receptor (TfR), divalent metal transporter (DMT1), copper transporter (CTR1), ATP7A/B, and ferroportin (FPN), regulate metal movement across the barriers is explored. Finally, the detrimental consequences of dysfunctional metal transport by brain barriers, as a result of endogenous disorders or exogenous insults, are discussed. Understanding the regulation of Fe and Cu homeostasis in the central nervous system aids in the design of new drugs targeted on the regulatory proteins at the brain barriers for the treatment of metal's deficiency or overload-related neurological diseases.
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