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Kosmachevskaya OV, Novikova NN, Yakunin SN, Topunov AF. Formation of Supplementary Metal-Binding Centers in Proteins under Stress Conditions. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:S180-S204. [PMID: 38621750 DOI: 10.1134/s0006297924140104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/21/2023] [Accepted: 10/29/2023] [Indexed: 04/17/2024]
Abstract
In many proteins, supplementary metal-binding centers appear under stress conditions. They are known as aberrant or atypical sites. Physico-chemical properties of proteins are significantly changed after such metal binding, and very stable protein aggregates are formed, in which metals act as "cross-linking" agents. Supplementary metal-binding centers in proteins often arise as a result of posttranslational modifications caused by reactive oxygen and nitrogen species and reactive carbonyl compounds. New chemical groups formed as a result of these modifications can act as ligands for binding metal ions. Special attention is paid to the role of cysteine SH-groups in the formation of supplementary metal-binding centers, since these groups are the main target for the action of reactive species. Supplementary metal binding centers may also appear due to unmasking of amino acid residues when protein conformation changing. Appearance of such centers is usually considered as a pathological process. Such unilateral approach does not allow to obtain an integral view of the phenomenon, ignoring cases when formation of metal complexes with altered proteins is a way to adjust protein properties, activity, and stability under the changed redox conditions. The role of metals in protein aggregation is being studied actively, since it leads to formation of non-membranous organelles, liquid condensates, and solid conglomerates. Some proteins found in such aggregates are typical for various diseases, such as Alzheimer's and Huntington's diseases, amyotrophic lateral sclerosis, and some types of cancer.
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Affiliation(s)
- Olga V Kosmachevskaya
- Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia
| | | | - Sergey N Yakunin
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Alexey F Topunov
- Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia.
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2
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Chaudhary S, Ashok A, Wise AS, Rana NA, McDonald D, Kritikos AE, Kong Q, Singh N. Upregulation of brain hepcidin in prion diseases. Prion 2021; 15:126-137. [PMID: 34224321 PMCID: PMC8259718 DOI: 10.1080/19336896.2021.1946377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 06/04/2021] [Accepted: 06/17/2021] [Indexed: 12/14/2022] Open
Abstract
Accumulation of redox-active iron in human sporadic Creutzfeldt-Jakob disease (sCJD) brain tissue and scrapie-infected mouse brains has been demonstrated previously. Here, we explored whether upregulation of local hepcidin secreted within the brain is the underlying cause of iron accumulation and associated toxicity. Using scrapie-infected mouse brains, we demonstrate transcriptional upregulation of hepcidin relative to controls. As a result, ferroportin (Fpn), the downstream effector of hepcidin and the only known iron export protein was downregulated, and ferritin, an iron storage protein was upregulated, suggesting increased intracellular iron. A similar transcriptional and translational upregulation of hepcidin, and decreased expression of Fpn and an increase in ferritin expression was observed in sCJD brain tissue. Further evaluation in human neuroblastoma cells (M17) exposed to synthetic mini-hepcidin showed downregulation of Fpn, upregulation of ferritin, and an increase in reactive oxygen species (ROS), resulting in cytotoxicity in a dose-dependent manner. Similar effects were noted in primary neurons isolated from mouse brain. As in M17 cells, primary neurons accumulated ferritin and ROS, and showed toxicity at five times lower concentration of mini-hepcidin. These observations suggest that upregulation of brain hepcidin plays a significant role in iron accumulation and associated neurotoxicity in human and animal prion disorders.
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Affiliation(s)
- Suman Chaudhary
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Ajay Ashok
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Aaron S. Wise
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Neil A. Rana
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Dallas McDonald
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Alexander E. Kritikos
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Qingzhong Kong
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Neena Singh
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
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Tarnacka B, Jopowicz A, Maślińska M. Copper, Iron, and Manganese Toxicity in Neuropsychiatric Conditions. Int J Mol Sci 2021; 22:ijms22157820. [PMID: 34360586 PMCID: PMC8346158 DOI: 10.3390/ijms22157820] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/12/2021] [Accepted: 07/20/2021] [Indexed: 12/18/2022] Open
Abstract
Copper, manganese, and iron are vital elements required for the appropriate development and the general preservation of good health. Additionally, these essential metals play key roles in ensuring proper brain development and function. They also play vital roles in the central nervous system as significant cofactors for several enzymes, including the antioxidant enzyme superoxide dismutase (SOD) and other enzymes that take part in the creation and breakdown of neurotransmitters in the brain. An imbalance in the levels of these metals weakens the structural, regulatory, and catalytic roles of different enzymes, proteins, receptors, and transporters and is known to provoke the development of various neurological conditions through different mechanisms, such as via induction of oxidative stress, increased α-synuclein aggregation and fibril formation, and stimulation of microglial cells, thus resulting in inflammation and reduced production of metalloproteins. In the present review, the authors focus on neurological disorders with psychiatric signs associated with copper, iron, and manganese excess and the diagnosis and potential treatment of such disorders. In our review, we described diseases related to these metals, such as aceruloplasminaemia, neuroferritinopathy, pantothenate kinase-associated neurodegeneration (PKAN) and other very rare classical NBIA forms, manganism, attention-deficit/hyperactivity disorder (ADHD), ephedrone encephalopathy, HMNDYT1-SLC30A10 deficiency (HMNDYT1), HMNDYT2-SLC39A14 deficiency, CDG2N-SLC39A8 deficiency, hepatic encephalopathy, prion disease and “prion-like disease”, amyotrophic lateral sclerosis, Huntington’s disease, Friedreich’s ataxia, and depression.
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Affiliation(s)
- Beata Tarnacka
- Department of Rehabilitation Medicine, Faculty of Medicine, Warsaw Medical University, Spartańska 1, 02-637 Warsaw, Poland
- Correspondence: ; Tel.: +48-603944804
| | - Anna Jopowicz
- Department of Rehabilitation, Eleonora Reicher National Institute of Geriatrics, Rheumatology and Rehabilitation, Spartańska 1, 02-637 Warsaw, Poland;
| | - Maria Maślińska
- Department of Early Arthritis, Eleonora Reicher National Institute of Geriatrics, Rheumatology and Rehabilitation, Spartańska 1, 02-637 Warsaw, Poland;
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Chansiw N, Kulprachakarn K, Paradee N, Prommaban A, Srichairatanakool S. Protection of Iron-Induced Oxidative Damage in Neuroblastoma (SH-SY5Y) Cells by Combination of 1-(N-Acetyl-6-aminohexyl)-3-hydroxy-2-methylpyridin-4-one and Green Tea Extract. Bioinorg Chem Appl 2021; 2021:5539666. [PMID: 33986790 PMCID: PMC8079199 DOI: 10.1155/2021/5539666] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 04/11/2021] [Indexed: 01/03/2023] Open
Abstract
Iron is a crucial trace element and essential for many cellular processes; however, excessive iron accumulation can induce oxidative stress and cell damage. Neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease, have been associated with altered iron homoeostasis causing altered iron distribution and accumulation in brain tissue. This study aims to investigate the protective effect of 1-(N-acetyl-6-aminohexyl)-3-hydroxy-2-methylpyridin-4-one (CM1) in combination with green tea extract (GTE) on iron-induced oxidative stress in neuroblastoma (SH-SY5Y) cells. Cells were cultured in medium with or without ferric chloride loading. Their viability and mitochondrial activity were assessed using MTT and JC-1 staining methods. Levels of the cellular labile iron pool (LIP), reactive oxygen species (ROS), and lipid-peroxidation products were determined using calcein acetoxymethyl ester, 2',7'-dichlorohydrofluorescein diacetate, and TBARS-based assays, respectively. The viability of iron-loaded cells was found to be significantly increased after treatment with CM1 (10 µM) for 24 h. CM1 co-treatment with GTE resulted in a greater protective effect than their monotherapy. Combination of CM1 and GTE also reduced mitochondrial disruption and LIP content and ROS and TBARS production. In conclusion, the combination of CM1 and GTE exhibits protection against iron-induced oxidative stress in neuroblastoma cells.
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Affiliation(s)
- Nittaya Chansiw
- School of Medicine, Mae Fah Luang University, Chiang Rai 57100, Thailand
| | - Kanokwan Kulprachakarn
- Research Institute for Health Science, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Narisara Paradee
- Oxidative Stress Cluster, Department of Biochemistry, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Adchara Prommaban
- Oxidative Stress Cluster, Department of Biochemistry, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Somdet Srichairatanakool
- Oxidative Stress Cluster, Department of Biochemistry, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
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The S-nitrosylation of parkin attenuated the ubiquitination of divalent metal transporter 1 in MPP +-treated SH-SY5Y cells. Sci Rep 2020; 10:15542. [PMID: 32968192 PMCID: PMC7511936 DOI: 10.1038/s41598-020-72630-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 09/02/2020] [Indexed: 11/19/2022] Open
Abstract
Abnormal iron accumulation caused by elevated levels of divalent metal transporter 1 (DMT1) contributes to progressive neurodegeneration in Parkinson's disease (PD). Parkin is a E3 ubiquitin ligase for the ubiquitination of DMT1. S-nitrosylated parkin (SNO-parkin) is commonly observed in PD. However, the effects of S-nitrosylation on the E3 ubiquitin ligase activity of parkin for the ubiquitination of DMT1 in PD are largely unknown. To elucidate the role of S-nitrosylated parkin and DMT1 in PD, SH-SY5Y cells were transfected with parkin, being treated with S-nitrosoglutathione (GSNO) and 1-methyl-4-phenylpyridinium (MPP+). The results showed increased levels of oxidized nitric oxide (NO) and S-nitrosylated parkin after the treatment of GSNO and MPP+ in parkin-transfected cells. Consistently, increased levels of DMT1, iron uptake and cell viability were observed. Interestingly, inhibition of S-nitrosylated parkin reduced the level of DMT1. Further, S-nitrosylation of parkin significantly inhibited the ubiquitination of DMT1. When HEK293T cells were transfected with plasmid of parkin with single site mutation (Cys241A, Cys260A, Cys323A), ubiquitination of DMT1 was also inhibited. However, the cells cotransfected with plasmids containing all three mutations, GSNO treatment did not affect the ubiquitination of DMT1. The expression of SNO-parkin and DMT1 protein in substantia nigra increased significantly gradually after 2 h, 4 h and 24 h with MPTP injection. These results indicate that the S-nitrosylation of parkin inhibits its E3 ubiquitin ligase activity for the ubiquitination of DMT1, which contributes to iron accumulation and degenerative process in PD. Targeted S-nitrosylation could provide a potential therapeutic strategy against PD.
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Prasad KN, Bondy SC. Oxidative and Inflammatory Events in Prion Diseases: Can They Be Therapeutic Targets? Curr Aging Sci 2020; 11:216-225. [PMID: 30636622 PMCID: PMC6635421 DOI: 10.2174/1874609812666190111100205] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 10/17/2018] [Accepted: 12/10/2018] [Indexed: 01/15/2023]
Abstract
Prion diseases are a group of incurable infectious terminal neurodegenerative diseases caused by the aggregated misfolded PrPsc in selected mammals including humans. The complex physical interaction between normal prion protein PrPc and infectious PrPsc causes conformational change from the α- helix structure of PrPc to the β-sheet structure of PrPsc, and this process is repeated. Increased oxidative stress is one of the factors that facilitate the conversion of PrPc to PrPsc. This overview presents evidence to show that increased oxidative stress and inflammation are involved in the progression of this disease. Evidence is given for the participation of redoxsensitive metals Cu and Fe with PrPsc inducing oxidative stress by disturbing the homeostasis of these metals. The fact that some antioxidants block the toxicity of misfolded PrPc peptide supports the role of oxidative stress in prion disease. After exogenous infection in mice, PrPsc enters the follicular dendritic cells where PrPsc replicates before neuroinvasion where they continue to replicate and cause inflammation leading to neurodegeneration. Therefore, reducing levels of oxidative stress and inflammation may decrease the rate of the progression of this disease. It may be an important order to reduce oxidative stress and inflammation at the same time. This may be achieved by increasing the levels of antioxidant enzymes by activating the Nrf2 pathway together with simultaneous administration of dietary and endogenous antioxidants. It is proposed that a mixture of micronutrients could enable these concurrent events thereby reducing the progression of human prion disease.
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Affiliation(s)
- Kedar N Prasad
- Engage Global, 245 El Faison Drive, San Rafael, CA, United States
| | - Stephen C Bondy
- Center for Occupational and Environmental Health, Department of Medicine, University of California, Irvine, CA 92697, United States
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Kell DB, Pretorius E. No effects without causes: the Iron Dysregulation and Dormant Microbes hypothesis for chronic, inflammatory diseases. Biol Rev Camb Philos Soc 2018; 93:1518-1557. [PMID: 29575574 PMCID: PMC6055827 DOI: 10.1111/brv.12407] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/12/2018] [Accepted: 02/15/2018] [Indexed: 12/11/2022]
Abstract
Since the successful conquest of many acute, communicable (infectious) diseases through the use of vaccines and antibiotics, the currently most prevalent diseases are chronic and progressive in nature, and are all accompanied by inflammation. These diseases include neurodegenerative (e.g. Alzheimer's, Parkinson's), vascular (e.g. atherosclerosis, pre-eclampsia, type 2 diabetes) and autoimmune (e.g. rheumatoid arthritis and multiple sclerosis) diseases that may appear to have little in common. In fact they all share significant features, in particular chronic inflammation and its attendant inflammatory cytokines. Such effects do not happen without underlying and initially 'external' causes, and it is of interest to seek these causes. Taking a systems approach, we argue that these causes include (i) stress-induced iron dysregulation, and (ii) its ability to awaken dormant, non-replicating microbes with which the host has become infected. Other external causes may be dietary. Such microbes are capable of shedding small, but functionally significant amounts of highly inflammagenic molecules such as lipopolysaccharide and lipoteichoic acid. Sequelae include significant coagulopathies, not least the recently discovered amyloidogenic clotting of blood, leading to cell death and the release of further inflammagens. The extensive evidence discussed here implies, as was found with ulcers, that almost all chronic, infectious diseases do in fact harbour a microbial component. What differs is simply the microbes and the anatomical location from and at which they exert damage. This analysis offers novel avenues for diagnosis and treatment.
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Affiliation(s)
- Douglas B. Kell
- School of ChemistryThe University of Manchester, 131 Princess StreetManchesterLancsM1 7DNU.K.
- The Manchester Institute of BiotechnologyThe University of Manchester, 131 Princess StreetManchesterLancsM1 7DNU.K.
- Department of Physiological SciencesStellenbosch University, Stellenbosch Private Bag X1Matieland7602South Africa
| | - Etheresia Pretorius
- Department of Physiological SciencesStellenbosch University, Stellenbosch Private Bag X1Matieland7602South Africa
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Rutin as a Potent Antioxidant: Implications for Neurodegenerative Disorders. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:6241017. [PMID: 30050657 PMCID: PMC6040293 DOI: 10.1155/2018/6241017] [Citation(s) in RCA: 198] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 04/29/2018] [Indexed: 12/16/2022]
Abstract
A wide range of neurodegenerative diseases (NDs), including Alzheimer's disease, Parkinson's disease, Huntington's disease, and prion diseases, share common mechanisms such as neuronal loss, apoptosis, mitochondrial dysfunction, oxidative stress, and inflammation. Intervention strategies using plant-derived bioactive compounds have been offered as a form of treatment for these debilitating conditions, as there are currently no remedies to prevent, reverse, or halt the progression of neuronal loss. Rutin, a glycoside of the flavonoid quercetin, is found in many plants and fruits, especially buckwheat, apricots, cherries, grapes, grapefruit, plums, and oranges. Pharmacological studies have reported the beneficial effects of rutin in many disease conditions, and its therapeutic potential in several models of NDs has created considerable excitement. Here, we have summarized the current knowledge on the neuroprotective mechanisms of rutin in various experimental models of NDs. The mechanisms of action reviewed in this article include reduction of proinflammatory cytokines, improved antioxidant enzyme activities, activation of the mitogen-activated protein kinase cascade, downregulation of mRNA expression of PD-linked and proapoptotic genes, upregulation of the ion transport and antiapoptotic genes, and restoration of the activities of mitochondrial complex enzymes. Taken together, these findings suggest that rutin may be a promising neuroprotective compound for the treatment of NDs.
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Toni M, Massimino ML, De Mario A, Angiulli E, Spisni E. Metal Dyshomeostasis and Their Pathological Role in Prion and Prion-Like Diseases: The Basis for a Nutritional Approach. Front Neurosci 2017; 11:3. [PMID: 28154522 PMCID: PMC5243831 DOI: 10.3389/fnins.2017.00003] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 01/03/2017] [Indexed: 12/11/2022] Open
Abstract
Metal ions are key elements in organisms' life acting like cofactors of many enzymes but they can also be potentially dangerous for the cell participating in redox reactions that lead to the formation of reactive oxygen species (ROS). Any factor inducing or limiting a metal dyshomeostasis, ROS production and cell injury may contribute to the onset of neurodegenerative diseases or play a neuroprotective action. Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, are a group of fatal neurodegenerative disorders affecting the central nervous system (CNS) of human and other mammalian species. The causative agent of TSEs is believed to be the scrapie prion protein PrPSc, the β sheet-rich pathogenic isoform produced by the conformational conversion of the α-helix-rich physiological isoform PrPC. The peculiarity of PrPSc is its ability to self-propagate in exponential fashion in cells and its tendency to precipitate in insoluble and protease-resistance amyloid aggregates leading to neuronal cell death. The expression “prion-like diseases” refers to a group of neurodegenerative diseases that share some neuropathological features with prion diseases such as the involvement of proteins (α-synuclein, amyloid β, and tau) able to precipitate producing amyloid deposits following conformational change. High social impact diseases such as Alzheimer's and Parkinson's belong to prion-like diseases. Accumulating evidence suggests that the exposure to environmental metals is a risk factor for the development of prion and prion-like diseases and that metal ions can directly bind to prion and prion-like proteins affecting the amount of amyloid aggregates. The diet, source of metal ions but also of natural antioxidant and chelating agents such as polyphenols, is an aspect to take into account in addressing the issue of neurodegeneration. Epidemiological data suggest that the Mediterranean diet, based on the abundant consumption of fresh vegetables and on low intake of meat, could play a preventive or delaying role in prion and prion-like neurodegenerative diseases. In this review, metal role in the onset of prion and prion-like diseases is dealt with from a nutritional, cellular, and molecular point of view.
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Affiliation(s)
- Mattia Toni
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University Rome, Italy
| | - Maria L Massimino
- National Research Council (CNR), Neuroscience Institute c/o Department of Biomedical Sciences, University of Padova Padova, Italy
| | - Agnese De Mario
- Department of Biomedical Sciences, University of Padova Padova, Italy
| | - Elisa Angiulli
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University Rome, Italy
| | - Enzo Spisni
- Department of Biological, Geological and Environmental Sciences, University of Bologna Bologna, Italy
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Proteins behaving badly. Substoichiometric molecular control and amplification of the initiation and nature of amyloid fibril formation: lessons from and for blood clotting. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 123:16-41. [DOI: 10.1016/j.pbiomolbio.2016.08.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 08/14/2016] [Accepted: 08/19/2016] [Indexed: 02/08/2023]
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Kim M, Kim EH, Choi BR, Woo HJ. Differentially expressed genes in iron-induced prion protein conversion. Biochem Biophys Res Commun 2016; 480:734-740. [PMID: 27983987 DOI: 10.1016/j.bbrc.2016.10.117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 10/27/2016] [Indexed: 01/26/2023]
Abstract
The conversion of the cellular prion protein (PrPC) to the protease-resistant isoform is the key event in chronic neurodegenerative diseases, including transmissible spongiform encephalopathies (TSEs). Increased iron in prion-related disease has been observed due to the prion protein-ferritin complex. Additionally, the accumulation and conversion of recombinant PrP (rPrP) is specifically derived from Fe(III) but not Fe(II). Fe(III)-mediated PK-resistant PrP (PrPres) conversion occurs within a complex cellular environment rather than via direct contact between rPrP and Fe(III). In this study, differentially expressed genes correlated with prion degeneration by Fe(III) were identified using Affymetrix microarrays. Following Fe(III) treatment, 97 genes were differentially expressed, including 85 upregulated genes and 12 downregulated genes (≥1.5-fold change in expression). However, Fe(II) treatment produced moderate alterations in gene expression without inducing dramatic alterations in gene expression profiles. Moreover, functional grouping of identified genes indicated that the differentially regulated genes were highly associated with cell growth, cell maintenance, and intra- and extracellular transport. These findings showed that Fe(III) may influence the expression of genes involved in PrP folding by redox mechanisms. The identification of genes with altered expression patterns in neural cells may provide insights into PrP conversion mechanisms during the development and progression of prion-related diseases.
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Affiliation(s)
- Minsun Kim
- Laboratory of Immunology and Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Republic of Korea
| | - Eun-Hee Kim
- Laboratory of Immunology and Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Republic of Korea
| | - Bo-Ran Choi
- Laboratory of Immunology and Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Republic of Korea; Solomon Snyder Department of Neuroscience, School of Medicine, Johns Hopkins University, PCTB1004, 725 N Wolfe Street, Baltimore, MD, USA
| | - Hee-Jong Woo
- Laboratory of Immunology and Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Republic of Korea.
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Frontzek K, Pfammatter M, Sorce S, Senatore A, Schwarz P, Moos R, Frauenknecht K, Hornemann S, Aguzzi A. Neurotoxic Antibodies against the Prion Protein Do Not Trigger Prion Replication. PLoS One 2016; 11:e0163601. [PMID: 27684562 PMCID: PMC5042507 DOI: 10.1371/journal.pone.0163601] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 09/12/2016] [Indexed: 01/07/2023] Open
Abstract
Prions are the infectious agents causing transmissible spongiform encephalopathies (TSE), progressive, inexorably lethal neurological diseases. Antibodies targeting the globular domain (GD) of the cellular prion protein PrPC trigger a neurotoxic syndrome morphologically and molecularly similar to prion disease. This phenomenon raises the question whether such antibodies induce infectious prions de novo. Here we exposed cerebellar organotypic cultured slices (COCS) to the neurotoxic antibody, POM1. We then inoculated COCS homogenates into tga20 mice, which overexpress PrPC and are commonly utilized as sensitive indicators of prion infectivity. None of the mice inoculated with COCS-derived lysates developed any signs of disease, and all mice survived for at least 200 days post-inoculation. In contrast, all mice inoculated with bona fide prions succumbed to TSE after 55–95 days. Post-mortem analyses did not reveal any signs of prion pathology in mice inoculated with POM1-COCS lysates. Also, lysates from POM1-exposed COCS were unable to convert PrP by quaking. Hence, anti-GD antibodies do not catalyze the generation of prion infectivity. These data indicate that prion replication can be separated from prion toxicity, and suggest that anti-GD antibodies exert toxicity by acting downstream of prion replication.
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Affiliation(s)
- Karl Frontzek
- Institute of Neuropathology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Manuela Pfammatter
- Institute of Neuropathology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Silvia Sorce
- Institute of Neuropathology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Assunta Senatore
- Institute of Neuropathology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Petra Schwarz
- Institute of Neuropathology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Rita Moos
- Institute of Neuropathology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Katrin Frauenknecht
- Institute of Neuropathology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Simone Hornemann
- Institute of Neuropathology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Adriano Aguzzi
- Institute of Neuropathology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
- * E-mail:
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Rivera NA, Novakofski J, Weng HY, Kelly A, Satterthwaite-Phillips D, Ruiz MO, Mateus-Pinilla N. Metals in obex and retropharyngeal lymph nodes of Illinois white-tailed deer and their variations associated with CWD status. Prion 2016; 9:48-58. [PMID: 25695915 PMCID: PMC4601235 DOI: 10.1080/19336896.2015.1019194] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Prion proteins (PrP(C)) are cell membrane glycoproteins that can be found in many cell types, but specially in neurons. Many studies have suggested PrP(C)'s participation in metal transport and cellular protection against stress in the central nervous system (CNS). On the other hand PrP(Sc), the misfolded isoform of PrP(C) and the pathogenic agent in transmissible spongiform encephalopathies (TSE), has been associated with brain metal dyshomeostasis in prion diseases. Thus, changes in metal concentration associated with protein misfolding and aggregation have been reported for human and animal prion diseases, as well as for other neurodegenerative disorders, such as Parkinson's and Alzheimer's disease. The use of metal concentrations in tissues as surrogate markers for early detection of TSEs has been suggested. Studies on the accumulation of metals in free-ranging white-tailed deer have not been conducted. This study established concentrations of copper, iron, manganese, and magnesium in 2 diagnostic tissues used for CWD testing (obex and retropharyngeal lymph nodes (RLN)). We compared these concentrations between tissues and in relation to CWD status. We established reference intervals (RIs) for these metals and explored their ability to discriminate between CWD-positive and CWD-negative animals. Our results indicate that independent of CWD status, white-tailed deer accumulate higher concentrations of Fe, Mn and Mg in RLN than in obex. White-tailed deer infected with CWD accumulated significantly lower concentrations of Mn and Fe than CWD-negative deer. These patterns differed from other species infected with prion diseases. Overlapping values between CWD positive and negative groups indicate that evaluation of these metals in obex and RLN may not be appropriate as a diagnostic tool for CWD infection in white-tailed deer. Because the CWD-negative deer were included in constructing the RIs, high specificities were expected and should be interpreted with caution. Due to the low sensitivity derived from the RIs, we do not recommend using metal concentrations for disease discrimination.
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Key Words
- AAS, atomic absorption spectroscopy
- AD, Alzheimer disease
- ASVCP, American Society for Veterinary Clinical Pathology
- BBB, blood brain barrier
- CI, confidence intervals
- CNS, central nervous system
- CP, choroid plexus
- CWD, chronic wasting disease
- Cu, copper
- Fe, iron
- ICP-MS, inductively coupled plasma mass spectrometry
- IDNR, Illinois Department of Natural Resources
- ISTC, Illinois Sustainable Technology Center
- ISWS, Illinois State Water Survey
- Mg, magnesium
- Mn, manganese
- PD, Parkinson disease
- PRNP, prion protein gene
- PrPC, cellular prion protein
- PrPSc, abnormal isoform of prion protein
- RIs, reference intervals
- RLN, retropharyngeal lymph nodes
- SOD, superoxide dismutase
- SSURGO, Soil Survey Geographic database
- STATSGO, State Soil Geographic Database
- TSE, transmissible spongiform enchephalopathies
- Tf, transferrin
- TfR, transferrin receptors
- chronic wasting disease
- copper
- iron
- magnesium
- manganese
- metals imbalance
- prion
- transmissible spongiform encephalopathy
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Affiliation(s)
- Nelda A Rivera
- a Illinois Natural History Survey ; University of Illinois at Urbana-Champaign ; Champaign , IL USA
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Haldar S, Tripathi A, Qian J, Beserra A, Suda S, McElwee M, Turner J, Hopfer U, Singh N. Prion protein promotes kidney iron uptake via its ferrireductase activity. J Biol Chem 2015; 290:5512-22. [PMID: 25572394 DOI: 10.1074/jbc.m114.607507] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Brain iron-dyshomeostasis is an important cause of neurotoxicity in prion disorders, a group of neurodegenerative conditions associated with the conversion of prion protein (PrP(C)) from its normal conformation to an aggregated, PrP-scrapie (PrP(Sc)) isoform. Alteration of iron homeostasis is believed to result from impaired function of PrP(C) in neuronal iron uptake via its ferrireductase activity. However, unequivocal evidence supporting the ferrireductase activity of PrP(C) is lacking. Kidney provides a relevant model for this evaluation because PrP(C) is expressed in the kidney, and ∼370 μg of iron are reabsorbed daily from the glomerular filtrate by kidney proximal tubule cells (PT), requiring ferrireductase activity. Here, we report that PrP(C) promotes the uptake of transferrin (Tf) and non-Tf-bound iron (NTBI) by the kidney in vivo and mainly NTBI by PT cells in vitro. Thus, uptake of (59)Fe administered by gastric gavage, intravenously, or intraperitoneally was significantly lower in PrP-knock-out (PrP(-/-)) mouse kidney relative to PrP(+/+) controls. Selective in vivo radiolabeling of plasma NTBI with (59)Fe revealed similar results. Expression of exogenous PrP(C) in immortalized PT cells showed localization on the plasma membrane and intracellular vesicles and increased transepithelial transport of (59)Fe-NTBI and to a smaller extent (59)Fe-Tf from the apical to the basolateral domain. Notably, the ferrireductase-deficient mutant of PrP (PrP(Δ51-89)) lacked this activity. Furthermore, excess NTBI and hemin caused aggregation of PrP(C) to a detergent-insoluble form, limiting iron uptake. Together, these observations suggest that PrP(C) promotes retrieval of iron from the glomerular filtrate via its ferrireductase activity and modulates kidney iron metabolism.
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Affiliation(s)
| | | | - Juan Qian
- From the Departments of Pathology and
| | | | | | | | - Jerrold Turner
- the Department of Pathology, University of Chicago, Chicago, Illinois 60637
| | - Ulrich Hopfer
- Physiology and Biophysics, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio 44106 and
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15
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Kim DH, Lee HM, Ryou C. Evaluation of infective property of recombinant prion protein amyloids in cultured cells overexpressing cellular prion protein. J Korean Med Sci 2014; 29:1604-9. [PMID: 25469058 PMCID: PMC4248579 DOI: 10.3346/jkms.2014.29.12.1604] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 11/06/2014] [Indexed: 11/22/2022] Open
Abstract
Misfolded isoform of prion protein (PrP), termed scrapie PrP (PrP(Sc)), tends to aggregate into various fibril forms. Previously, we reported various conditions that affect aggregation of recombinant PrP into amyloids. Because amyloidogenesis of PrP is closely associated with transmissible spongiform encephalopathies such as Creutzfeldt-Jakob disease in humans, we investigated infectivity of recombinant PrP amyloids generated in vitro. Using cultured cell lines which overexpress cellular PrP of different species, we measured the level of de novo synthesized PrP(Sc) in cells inoculated with recombinant mouse PrP amyloids. While PrP-overexpressing cells were susceptible to mouse-adapted scrapie prions used as the positive control, demonstrating the species barrier effect, infection with amyloids made of truncated recombinant PrP (PrP[89-230]) failed to form and propagate PrP(Sc) even in the cells that express mouse cellular PrP. This suggests that infectivity of PrP amyloids generated in vitro is different from that of natural prions. Recombinant PrP (89-230) amyloids tested in the current study retain no or a minute level, if any, of prion infectivity.
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Affiliation(s)
- Dae-Hwan Kim
- Department of Pharmacy, College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Korea
| | - Hye-Mi Lee
- Department of Pharmacy, College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Korea
| | - Chongsuk Ryou
- Department of Pharmacy, College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Korea
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Affiliation(s)
- Neena Singh
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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Singh N, Haldar S, Tripathi AK, McElwee MK, Horback K, Beserra A. Iron in neurodegenerative disorders of protein misfolding: a case of prion disorders and Parkinson's disease. Antioxid Redox Signal 2014; 21:471-84. [PMID: 24512387 PMCID: PMC4076993 DOI: 10.1089/ars.2014.5874] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
SIGNIFICANCE Intracellular and extracellular aggregation of a specific protein or protein fragments is the principal pathological event in several neurodegenerative conditions. We describe two such conditions: sporadic Creutzfeldt-Jakob disease (sCJD), a rare but potentially infectious and invariably fatal human prion disorder, and Parkinson's disease (PD), a common neurodegenerative condition second only to Alzheimer's disease in prevalence. In sCJD, a cell surface glycoprotein known as the prion protein (PrP(C)) undergoes a conformational change to PrP-scrapie, a pathogenic and infectious isoform that accumulates in the brain parenchyma as insoluble aggregates. In PD, α-synuclein, a cytosolic protein, forms insoluble aggregates that accumulate in neurons of the substantia nigra and cause neurotoxicity. RECENT ADVANCES Although distinct processes are involved in the pathogenesis of sCJD and PD, both share brain iron dyshomeostasis as a common associated feature that is reflected in the cerebrospinal fluid in a disease-specific manner. CRITICAL ISSUES Since PrP(C) and α-synuclein play a significant role in maintaining cellular iron homeostasis, it is important to understand whether the aggregation of these proteins and iron dyshomeostasis are causally related. Here, we discuss recent information on the normal function of PrP(C) and α-synuclein in cellular iron metabolism and the cellular and biochemical processes that contribute to iron imbalance in sCJD and PD. FUTURE DIRECTIONS Improved understanding of the relationship between brain iron imbalance and protein aggregation is likely to help in the development of therapeutic strategies that can restore brain iron homeostasis and mitigate neurotoxicity.
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Affiliation(s)
- Neena Singh
- 1 Department of Pathology, Case Western Reserve University , Cleveland, Ohio
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18
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Braidy N, Poljak A, Marjo C, Rutlidge H, Rich A, Jayasena T, Inestrosa NC, Sachdev P. Metal and complementary molecular bioimaging in Alzheimer's disease. Front Aging Neurosci 2014; 6:138. [PMID: 25076902 PMCID: PMC4098123 DOI: 10.3389/fnagi.2014.00138] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 06/09/2014] [Indexed: 12/30/2022] Open
Abstract
Alzheimer's disease (AD) is the leading cause of dementia in the elderly, affecting over 27 million people worldwide. AD represents a complex neurological disorder which is best understood as the consequence of a number of interconnected genetic and lifestyle variables, which culminate in multiple changes to brain structure and function. These can be observed on a gross anatomical level in brain atrophy, microscopically in extracellular amyloid plaque and neurofibrillary tangle formation, and at a functional level as alterations of metabolic activity. At a molecular level, metal dyshomeostasis is frequently observed in AD due to anomalous binding of metals such as Iron (Fe), Copper (Cu), and Zinc (Zn), or impaired regulation of redox-active metals which can induce the formation of cytotoxic reactive oxygen species and neuronal damage. Metal chelators have been administered therapeutically in transgenic mice models for AD and in clinical human AD studies, with positive outcomes. As a result, neuroimaging of metals in a variety of intact brain cells and tissues is emerging as an important tool for increasing our understanding of the role of metal dysregulation in AD. Several imaging techniques have been used to study the cerebral metallo-architecture in biological specimens to obtain spatially resolved data on chemical elements present in a sample. Hyperspectral techniques, such as particle-induced X-ray emission (PIXE), energy dispersive X-ray spectroscopy (EDS), X-ray fluorescence microscopy (XFM), synchrotron X-ray fluorescence (SXRF), secondary ion mass spectrometry (SIMS), and laser ablation inductively coupled mass spectrometry (LA-ICPMS) can reveal relative intensities and even semi-quantitative concentrations of a large set of elements with differing spatial resolution and detection sensitivities. Other mass spectrometric and spectroscopy imaging techniques such as laser ablation electrospray ionization mass spectrometry (LA ESI-MS), MALDI imaging mass spectrometry (MALDI-IMS), and Fourier transform infrared spectroscopy (FTIR) can be used to correlate changes in elemental distribution with the underlying pathology in AD brain specimens. Taken together, these techniques provide new techniques to probe the pathobiology of AD and pave the way for identifying new therapeutic targets. The current review aims to discuss the advantages and challenges of using these emerging elemental and molecular imaging techniques, and highlight clinical achievements in AD research using bioimaging techniques.
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Affiliation(s)
- Nady Braidy
- Faculty of Medicine, Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales Sydney, NSW, Australia
| | - Anne Poljak
- Faculty of Medicine, Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales Sydney, NSW, Australia ; Bioanalytical Mass Spectrometry Facility, Mark Wainwright Analytical Centre, University of New South Wales Sydney, NSW, Australia ; Faculty of Medicine, School of Medical Sciences, University of New South Wales Sydney, NSW, Australia
| | - Christopher Marjo
- Solid State and Elemental Analysis Unit, Mark Wainwright Analytical Centre, University of New South Wales Sydney, NSW, Australia
| | - Helen Rutlidge
- Solid State and Elemental Analysis Unit, Mark Wainwright Analytical Centre, University of New South Wales Sydney, NSW, Australia
| | - Anne Rich
- Solid State and Elemental Analysis Unit, Mark Wainwright Analytical Centre, University of New South Wales Sydney, NSW, Australia
| | - Tharusha Jayasena
- Faculty of Medicine, Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales Sydney, NSW, Australia
| | - Nibaldo C Inestrosa
- Faculty of Biological Sciences, Centre for Ageing and Regeneration, P. Catholic University of Chile Santiago, Chile
| | - Perminder Sachdev
- Faculty of Medicine, Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales Sydney, NSW, Australia ; Euroa Centre, Neuropsychiatric Institute, Prince of Wales Hospital Sydney, NSW, Australia
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19
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Singh N, Haldar S, Tripathi AK, Horback K, Wong J, Sharma D, Beserra A, Suda S, Anbalagan C, Dev S, Mukhopadhyay CK, Singh A. Brain iron homeostasis: from molecular mechanisms to clinical significance and therapeutic opportunities. Antioxid Redox Signal 2014; 20:1324-63. [PMID: 23815406 PMCID: PMC3935772 DOI: 10.1089/ars.2012.4931] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Iron has emerged as a significant cause of neurotoxicity in several neurodegenerative conditions, including Alzheimer's disease (AD), Parkinson's disease (PD), sporadic Creutzfeldt-Jakob disease (sCJD), and others. In some cases, the underlying cause of iron mis-metabolism is known, while in others, our understanding is, at best, incomplete. Recent evidence implicating key proteins involved in the pathogenesis of AD, PD, and sCJD in cellular iron metabolism suggests that imbalance of brain iron homeostasis associated with these disorders is a direct consequence of disease pathogenesis. A complete understanding of the molecular events leading to this phenotype is lacking partly because of the complex regulation of iron homeostasis within the brain. Since systemic organs and the brain share several iron regulatory mechanisms and iron-modulating proteins, dysfunction of a specific pathway or selective absence of iron-modulating protein(s) in systemic organs has provided important insights into the maintenance of iron homeostasis within the brain. Here, we review recent information on the regulation of iron uptake and utilization in systemic organs and within the complex environment of the brain, with particular emphasis on the underlying mechanisms leading to brain iron mis-metabolism in specific neurodegenerative conditions. Mouse models that have been instrumental in understanding systemic and brain disorders associated with iron mis-metabolism are also described, followed by current therapeutic strategies which are aimed at restoring brain iron homeostasis in different neurodegenerative conditions. We conclude by highlighting important gaps in our understanding of brain iron metabolism and mis-metabolism, particularly in the context of neurodegenerative disorders.
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Affiliation(s)
- Neena Singh
- 1 Department of Pathology, Case Western Reserve University , Cleveland, Ohio
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20
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Mot AI, Wedd AG, Sinclair L, Brown DR, Collins SJ, Brazier MW. Metal attenuating therapies in neurodegenerative disease. Expert Rev Neurother 2014; 11:1717-45. [DOI: 10.1586/ern.11.170] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Singh A, Haldar S, Horback K, Tom C, Zhou L, Meyerson H, Singh N. Prion protein regulates iron transport by functioning as a ferrireductase. J Alzheimers Dis 2013; 35:541-52. [PMID: 23478311 DOI: 10.3233/jad-130218] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Prion protein (PrPC) is implicated in the pathogenesis of prion disorders, but its normal function is unclear. We demonstrate that PrPC is a ferrireductase (FR), and its absence causes systemic iron deficiency in PrP knock-out mice (PrP-/-). When exposed to non-transferrin-bound (NTB) radioactive-iron (59FeCl3) by gastric-gavage, PrP-/- mice absorb significantly more 59Fe from the intestinal lumen relative to controls, indicating appropriate systemic response to the iron deficiency. Chronic exposure to excess dietary iron corrects this deficiency, but unlike wild-type (PrP+/+) controls that remain iron over-loaded, PrP-/- mice revert back to the iron deficient phenotype after 5 months of chase on normal diet. Bone marrow (BM) preparations of PrP-/- mice on normal diet show relatively less stainable iron, and this phenotype is only partially corrected by intraperitoneal administration of excess iron-dextran. Cultured PrP-/- BM-macrophages incorporate significantly less NTB-59Fe in the absence or presence of excess extracellular iron, indicating reduced uptake and/or storage of available iron in the absence of PrPC. When expressed in neuroblastoma cells, PrPC exhibits NAD(P)H-dependent cell-surface and intracellular FR activity that requires the copper-binding octa-peptide-repeat region and linkage to the plasma membrane for optimal function. Incorporation of NTB-59Fe by neuroblastoma cells correlates with FR activity of PrPC, implicating PrPC in cellular iron uptake and metabolism. These observations explain the correlation between PrPC expression and cellular iron levels, and the cause of iron imbalance in sporadic-Creutzfeldt-Jakob-disease brains where PrPC accumulates as insoluble aggregates.
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Affiliation(s)
- Ajay Singh
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
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22
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Abstract
The infectious agent of the transmissible spongiform encephalopathies, or prion diseases, has been the center of intense debate for decades. Years of studies have provided overwhelming evidence to support the prion hypothesis that posits a protein conformal infectious agent is responsible for the transmissibility of the disease. The recent studies that generate prion infectivity with purified bacterially expressed recombinant prion protein not only provides convincing evidence supporting the core of the prion hypothesis, that a pathogenic conformer of host prion protein is able to seed the conversion of its normal counterpart to the likeness of itself resulting in the replication of the pathogenic conformer and occurrence of disease, they also indicate the importance of cofactors, particularly lipid or lipid-like molecules, in forming the protein conformation-based infectious agent. This article reviews the literature regarding the chemical nature of the infectious agent and the potential contribution from lipid molecules to prion infectivity, and discusses the important remaining questions in this research area.
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Affiliation(s)
- Fei Wang
- Department of Molecular and Cellular Biochemistry, Ohio State University, 1645 Neil Ave., Columbus, OH 43210, USA.
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23
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Choi BR, Lee J, Kim SY, Yim I, Kim EH, Woo HJ. Prion protein conversion induced by trivalent iron in vesicular trafficking. Biochem Biophys Res Commun 2013; 432:539-44. [PMID: 23416082 DOI: 10.1016/j.bbrc.2013.02.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 02/06/2013] [Indexed: 11/19/2022]
Abstract
Iron dyshomeostasis has been observed in prion diseases; however, little is known regarding the contribution of the oxidation state of iron to prion protein (PrP) conversion. In this study, PrP(C)-deficient HpL3-4 cells were exposed to divalent [Fe(II)] or trivalent [Fe(III)] iron, followed by exogenous recombinant PrP (rPrP) treatment. We then analyzed the accumulation of internalized rPrP and its biochemical properties, including its resistance to both proteinase K (PK) digestion and detergent solubility. Fe(III), but not Fe(II), induced the accumulation of internalized rPrP, which was partially converted to detergent-insoluble and PK-resistant PrP (PrP(res)). The Fe(III)-induced PrP(res) generation required an intact cell structure, and it was hindered by U18666A, an inhibitor of vesicular trafficking, but not by NH4Cl, an inhibitor of endolysosomal acidification. These observations implicated that the Fe(III)-mediated PrP(res) conversion likely occurs during endosomal vesicular trafficking rather than in the acidic environment of lysosomes.
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Affiliation(s)
- Bo-Ran Choi
- Laboratory of Immunology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Korea
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24
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Arena G, La Mendola D, Pappalardo G, Sóvágó I, Rizzarelli E. Interactions of Cu2+ with prion family peptide fragments: Considerations on affinity, speciation and coordination. Coord Chem Rev 2012. [DOI: 10.1016/j.ccr.2012.03.038] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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25
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Agatha S, Simon P. On the Nature of Tintinnid Loricae (Ciliophora: Spirotricha: Tintinnina): a Histochemical, Enzymatic, EDX, and High-resolution TEM Study. ACTA PROTOZOOL 2012; 51:1-19. [PMID: 22988335 PMCID: PMC3442249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Tintinnids (Ciliophora: Spirotricha: Tintinnina) are occasionally the dominant ciliates in the marine plankton. The tintinnid loricae are minute artworks fascinating scientists for more than 230 years, but their chemical composition remained unclear, viz., chitinous or proteinaceous substances were discussed. Since sedimenting loricae contribute to the flux of elements and organic compounds in the oceans, knowledge about their nature is necessary in assessing their ecological role. Previous techniques and new methods, e.g. enzymatic digestion and high-resolution transmission electron microscopy, are applied in the present study. A chitinous nature of the loricae is rejected by the Van-Wisselingh test and failure of chitinase digestion. Only proteins might show a resistance against strong hot bases (KOH at 160°C for ~ 40 min. in tintinnid loricae) similar to that of chitin. Actually, the presence of nitrogen in the EDX analyses and the digestion of at least some loricae by proteinase K strongly indicate a proteinaceous nature. Furthermore, the crystal lattice revealed by high-resolution TEM in Eutintinnus loricae is similar to the proteinaceous surface layer (S-layer) of archaea, and the striation recognizable in transverse sections of Eutintinnus loricae has a periodicity resembling that of the crystalline proteins in the extruded trichocysts of Paramecium and Frontonia. The proteolytic resistance of some loricae does not reject the idea of a proteinaceous nature, as proteins in S-layers of some archaea and in most naturally occurring prions show comparable reactions. The data from the present study and the literature indicate proteins in the loricae of thirteen genera. Differences in the proteolytic resistance and staining properties between genera and congeners are probably due to deviations in the protein composition and the additional substances, e.g. lipids, carbohydrates. At the present state of knowledge, correlations between lorica structure, wall texture, ultrastructure of the lorica forming granules, and the histochemical and enzymatic findings are not evident. Therefore, further studies are required to estimate the taxonomic significance of these features and the ecological role of sedimenting loricae.
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Affiliation(s)
- Sabine Agatha
- Department of Organismic Biology, University of Salzburg, Salzburg, Austria
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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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Martin DP, Anantharam V, Jin H, Witte T, Houk R, Kanthasamy A, Kanthasamy AG. Infectious prion protein alters manganese transport and neurotoxicity in a cell culture model of prion disease. Neurotoxicology 2011; 32:554-62. [PMID: 21871919 DOI: 10.1016/j.neuro.2011.07.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 07/20/2011] [Accepted: 07/21/2011] [Indexed: 01/26/2023]
Abstract
Protein misfolding and aggregation are considered key features of many neurodegenerative diseases, but biochemical mechanisms underlying protein misfolding and the propagation of protein aggregates are not well understood. Prion disease is a classical neurodegenerative disorder resulting from the misfolding of endogenously expressed normal cellular prion protein (PrP(C)). Although the exact function of PrP(C) has not been fully elucidated, studies have suggested that it can function as a metal binding protein. Interestingly, increased brain manganese (Mn) levels have been reported in various prion diseases indicating divalent metals also may play a role in the disease process. Recently, we reported that PrP(C) protects against Mn-induced cytotoxicity in a neural cell culture model. To further understand the role of Mn in prion diseases, we examined Mn neurotoxicity in an infectious cell culture model of prion disease. Our results show CAD5 scrapie-infected cells were more resistant to Mn neurotoxicity as compared to uninfected cells (EC(50)=428.8 μM for CAD5 infected cells vs. 211.6 μM for uninfected cells). Additionally, treatment with 300 μM Mn in persistently infected CAD5 cells showed a reduction in mitochondrial impairment, caspase-3 activation, and DNA fragmentation when compared to uninfected cells. Scrapie-infected cells also showed significantly reduced Mn uptake as measured by inductively coupled plasma-mass spectrometry (ICP-MS), and altered expression of metal transporting proteins DMT1 and transferrin. Together, our data indicate that conversion of PrP to the pathogenic isoform enhances its ability to regulate Mn homeostasis, and suggest that understanding the interaction of metals with disease-specific proteins may provide further insight to protein aggregation in neurodegenerative diseases.
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Affiliation(s)
- Dustin P Martin
- Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicity, Ames, IA 50011, USA
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Haigh CL, McGlade AR, Lewis V, Masters CL, Lawson VA, Collins SJ. Acute exposure to prion infection induces transient oxidative stress progressing to be cumulatively deleterious with chronic propagation in vitro. Free Radic Biol Med 2011; 51:594-608. [PMID: 21466851 DOI: 10.1016/j.freeradbiomed.2011.03.035] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2010] [Revised: 03/03/2011] [Accepted: 03/28/2011] [Indexed: 01/01/2023]
Abstract
Neuronal loss is a pathological feature of prion diseases for which increased reactive oxygen species (ROS) and consequent oxidative stress is one proposed mechanism. The processes underlying ROS production in prion disease and the precise relationship to misfolding of the prion protein remain obscure. Using cell culture models of prion infection we found that cells demonstrate a rapid, prion protein (PrP) dependent, increase in intracellular ROS following exposure to infectious inoculum. ROS production correlated with internalisation and increased intracellular protease resistant PrP (PrP(Res)). The ROS increase was predominantly lysosomal in origin but not sustained, with cells adapting within 48 hours. Overall ROS levels remained normal in the chronically prion infected cell population; however a subpopulation characterised by loss of membrane phosphatidylserine asymmetry exhibited highly peroxidised intracellular aggregates that localised with PrP and intense caspase activation. These apoptotic cells showed increased ROS closely correlating with increased PrP(Res). Our findings demonstrate that a PrP-dependent, transient, increase in intracellular ROS is characteristic of acute cellular prion infection, while chronic phases of prion infection in vitro are associated with a significant subpopulation manifesting apoptosis accompanying heightened oxidative stress and increased PrP(Res) burden. Such observations strengthen the direct links between heightened ROS and ongoing prion propagation with eventual cellular demise.
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Affiliation(s)
- Cathryn L Haigh
- Department of Pathology, The University of Melbourne, Parkville, 3010, Australia
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Huzarewich RLCH, Medina S, Robertson C, Parchaliuk D, Booth SA. Transcriptional modulation in a leukocyte-depleted splenic cell population during prion disease. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2011; 74:1504-1520. [PMID: 22043911 DOI: 10.1080/15287394.2011.618979] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Prion replication in the periphery precedes neuroinvasion in many experimental rodent scrapie models, and in natural sheep scrapie and chronic wasting disease (CWD) in cervids. Prions propagate in the germinal centers of secondary lymphoid organs and are strongly associated with follicular dendritic cells (FDC) and possibly circulating dendritic cells and macrophages. Given the importance of lymphoid organs in prion disease transmission and pathogenesis, gene expression studies may reveal host factors or biological pathways related to prion replication and accumulation. A procedure was developed to enrich for FDC, dendritic cells, and macrophages prior to the investigation of transcriptional alterations in murine splenic cells during prion pathogenesis. In total, 1753 transcripts exhibited fold changes greater than three (false discovery rates less than 2%) in this population isolated from spleens of prion-infected versus uninfected mice. The gene for the small leucine-rich proteoglycan decorin (DCN) was one of the genes most overexpressed in infected mice, and the splenic protein levels mirrored this in mice infected with scrapie as well as bovine spongiform encephalopathy (BSE) and variant Creutzfeldt-Jakob disease (vCJD). A number of groups of functionally related genes were also significantly decreased in infected spleens. These included genes related to iron metabolism and homeostasis, pathways that have also been implicated in prion pathogenesis in the brain. These gene expression alterations provide insights into the molecular mechanisms underlying prion disease pathogenesis and may serve as a pool of potential surrogate markers for the early detection and diagnosis of some prion diseases.
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Affiliation(s)
- Rhiannon L C H Huzarewich
- Molecular PathoBiology, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
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Kell DB. Towards a unifying, systems biology understanding of large-scale cellular death and destruction caused by poorly liganded iron: Parkinson's, Huntington's, Alzheimer's, prions, bactericides, chemical toxicology and others as examples. Arch Toxicol 2010; 84:825-89. [PMID: 20967426 PMCID: PMC2988997 DOI: 10.1007/s00204-010-0577-x] [Citation(s) in RCA: 286] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Accepted: 07/14/2010] [Indexed: 12/11/2022]
Abstract
Exposure to a variety of toxins and/or infectious agents leads to disease, degeneration and death, often characterised by circumstances in which cells or tissues do not merely die and cease to function but may be more or less entirely obliterated. It is then legitimate to ask the question as to whether, despite the many kinds of agent involved, there may be at least some unifying mechanisms of such cell death and destruction. I summarise the evidence that in a great many cases, one underlying mechanism, providing major stresses of this type, entails continuing and autocatalytic production (based on positive feedback mechanisms) of hydroxyl radicals via Fenton chemistry involving poorly liganded iron, leading to cell death via apoptosis (probably including via pathways induced by changes in the NF-κB system). While every pathway is in some sense connected to every other one, I highlight the literature evidence suggesting that the degenerative effects of many diseases and toxicological insults converge on iron dysregulation. This highlights specifically the role of iron metabolism, and the detailed speciation of iron, in chemical and other toxicology, and has significant implications for the use of iron chelating substances (probably in partnership with appropriate anti-oxidants) as nutritional or therapeutic agents in inhibiting both the progression of these mainly degenerative diseases and the sequelae of both chronic and acute toxin exposure. The complexity of biochemical networks, especially those involving autocatalytic behaviour and positive feedbacks, means that multiple interventions (e.g. of iron chelators plus antioxidants) are likely to prove most effective. A variety of systems biology approaches, that I summarise, can predict both the mechanisms involved in these cell death pathways and the optimal sites of action for nutritional or pharmacological interventions.
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Affiliation(s)
- Douglas B Kell
- School of Chemistry and the Manchester Interdisciplinary Biocentre, The University of Manchester, Manchester M1 7DN, UK.
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Das D, Luo X, Singh A, Gu Y, Ghosh S, Mukhopadhyay CK, Chen SG, Sy MS, Kong Q, Singh N. Paradoxical role of prion protein aggregates in redox-iron induced toxicity. PLoS One 2010; 5:e11420. [PMID: 20625431 PMCID: PMC2897850 DOI: 10.1371/journal.pone.0011420] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Accepted: 06/07/2010] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Imbalance of iron homeostasis has been reported in sporadic Creutzfeldt-Jakob-disease (sCJD) affected human and scrapie infected animal brains, but the contribution of this phenotype to disease associated neurotoxicity is unclear. METHODOLOGY/PRINCIPAL FINDINGS Using cell models of familial prion disorders, we demonstrate that exposure of cells expressing normal prion protein (PrP(C)) or mutant PrP forms to a source of redox-iron induces aggregation of PrP(C) and specific mutant PrP forms. Initially this response is cytoprotective, but becomes increasingly toxic with time due to accumulation of PrP-ferritin aggregates. Mutant PrP forms that do not aggregate are not cytoprotective, and cells show signs of acute toxicity. Intracellular PrP-ferritin aggregates induce the expression of LC3-II, indicating stimulation of autophagy in these cells. Similar observations are noted in sCJD and scrapie infected hamster brains, lending credence to these results. Furthermore, phagocytosis of PrP-ferritin aggregates by astrocytes is cytoprotective, while culture in astrocyte conditioned medium (CM) shows no measurable effect. Exposure to H(2)O(2), on the other hand, does not cause aggregation of PrP, and cells show acute toxicity that is alleviated by CM. CONCLUSIONS/SIGNIFICANCE These observations suggest that aggregation of PrP in response to redox-iron is cytoprotective. However, subsequent co-aggregation of PrP with ferritin induces intracellular toxicity unless the aggregates are degraded by autophagosomes or phagocytosed by adjacent scavenger cells. H(2)O(2), on the other hand, does not cause aggregation of PrP, and induces toxicity through extra-cellular free radicals. Together with previous observations demonstrating imbalance of iron homeostasis in prion disease affected brains, these observations provide insight into the mechanism of neurotoxicity by redox-iron, and the role of PrP in this process.
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Affiliation(s)
- Dola Das
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Xiu Luo
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Ajay Singh
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Yaping Gu
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Soumya Ghosh
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | | | - Shu G. Chen
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Man-Sun Sy
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Qingzhong Kong
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Neena Singh
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
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Singh N, Singh A, Das D, Mohan ML. Redox control of prion and disease pathogenesis. Antioxid Redox Signal 2010; 12:1271-94. [PMID: 19803746 PMCID: PMC2864664 DOI: 10.1089/ars.2009.2628] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Revised: 09/22/2009] [Accepted: 10/03/2009] [Indexed: 11/12/2022]
Abstract
Imbalance of brain metal homeostasis and associated oxidative stress by redox-active metals like iron and copper is an important trigger of neurotoxicity in several neurodegenerative conditions, including prion disorders. Whereas some reports attribute this to end-stage disease, others provide evidence for specific mechanisms leading to brain metal dyshomeostasis during disease progression. In prion disorders, imbalance of brain-iron homeostasis is observed before end-stage disease and worsens with disease progression, implicating iron-induced oxidative stress in disease pathogenesis. This is an unexpected observation, because the underlying cause of brain pathology in all prion disorders is PrP-scrapie (PrP(Sc)), a beta-sheet-rich conformation of a normal glycoprotein, the prion protein (PrP(C)). Whether brain-iron dyshomeostasis occurs because of gain of toxic function by PrP(Sc) or loss of normal function of PrP(C) remains unclear. In this review, we summarize available evidence suggesting the involvement of oxidative stress in prion-disease pathogenesis. Subsequently, we review the biology of PrP(C) to highlight its possible role in maintaining brain metal homeostasis during health and the contribution of PrP(Sc) in inducing brain metal imbalance with disease progression. Finally, we discuss possible therapeutic avenues directed at restoring brain metal homeostasis and alleviating metal-induced oxidative stress in prion disorders.
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Affiliation(s)
- Neena Singh
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio 44106, USA
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Eiríksson T, Björnsson H, Gudmundsdóttir KB, Kristinsson J, Jóhannesson T. The distribution of four trace elements (Fe, Mn, Cu, Zn) in forage and the relation to scrapie in Iceland. Acta Vet Scand 2010; 52:34. [PMID: 20492671 PMCID: PMC2890668 DOI: 10.1186/1751-0147-52-34] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Accepted: 05/21/2010] [Indexed: 10/31/2022] Open
Abstract
BACKGROUND Previous studies indicated that the iron (Fe)/manganese (Mn) ratio in forage of sheep was significantly higher on scrapie-afflicted farms than on farms in other scrapie categories. This study was conducted to examine whether Fe and Mn in forage of sheep varied in general according to the scrapie status of different areas in the country. Copper (Cu) and zinc (Zn) were also included because of a possible relation to scrapie. METHODS The country was subdivided into seven Areas (I-VII). Three Areas (I, IV, VII) were designated scrapie-free (never diagnosed or eradicated) and three as scrapie-endemic (II, III, VI); status of Area V was taken as unsettled. Of the harvest 2007 1552 samples were analysed from 344 farms all over the country, mostly grass silage from plastic bales (>90%) and from the first cut (70% or more). Results were expressed as mg kg(-1) dry matter. RESULTS Fe varied enormously from less than 100 mg kg(-1) to 5000 mg kg(-1). Mn varied nearly thirtyfold (17-470 mg kg(-1)). Fe concentration was significantly lower in Area I than in Areas II, V and VI. Mn concentration was significantly higher in Areas I, IV and VII than in Areas II, III, V and VI. The Fe/Mn ratio was significantly less in Area I than in the other areas (except Area IV). Mean Cu concentration was 6.6-8.3 mg kg(-1) and the mean Zn concentration was 24-29 mg kg(-1). They differed significantly in some areas. CONCLUSIONS 1) Fe tended to be in lower amounts in sheep forage in scrapie-free than in endemic areas; 2) Mn was in higher amounts in forage in scrapie-free than endemic areas; 3) the Fe/Mn ratio was lower in scrapie-free than in endemic areas; 4) the Fe/Mn ratio may possibly be used as an indicator of scrapie status; 5) Cu and Zn in sheep forage were not related to scrapie; 6) further study on the role of Fe and Mn in the occurrence of scrapie in Iceland is needed.
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Bhupanapadu Sunkesula SR, Luo X, Das D, Singh A, Singh N. Iron content of ferritin modulates its uptake by intestinal epithelium: implications for co-transport of prions. Mol Brain 2010; 3:14. [PMID: 20429907 PMCID: PMC2873590 DOI: 10.1186/1756-6606-3-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 04/29/2010] [Indexed: 11/13/2022] Open
Abstract
The spread of Chronic Wasting Disease (CWD) in the deer and elk population has caused serious public health concerns due to its potential to infect farm animals and humans. Like other prion disorders such a sporadic Creutzfeldt-Jakob-disease of humans and Mad Cow Disease of cattle, CWD is caused by PrP-scrapie (PrPSc), a β-sheet rich isoform of a normal cell surface glycoprotein, the prion protein (PrPC). Since PrPSc is sufficient to cause infection and neurotoxicity if ingested by a susceptible host, it is important to understand the mechanism by which it crosses the stringent epithelial cell barrier of the small intestine. Possible mechanisms include co-transport with ferritin in ingested food and uptake by dendritic cells. Since ferritin is ubiquitously expressed and shares considerable homology among species, co-transport of PrPSc with ferritin can result in cross-species spread with deleterious consequences. We have used a combination of in vitro and in vivo models of intestinal epithelial cell barrier to understand the role of ferritin in mediating PrPSc uptake and transport. In this report, we demonstrate that PrPSc and ferritin from CWD affected deer and elk brains and scrapie from sheep resist degradation by digestive enzymes, and are transcytosed across a tight monolayer of human epithelial cells with significant efficiency. Likewise, ferritin from hamster brains is taken up by mouse intestinal epithelial cells in vivo, indicating that uptake of ferritin is not limited by species differences as described for prions. More importantly, the iron content of ferritin determines its efficiency of uptake and transport by Caco-2 cells and mouse models, providing insight into the mechanism(s) of ferritin and PrPSc uptake by intestinal epithelial cells.
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Roth JA, Singleton S, Feng J, Garrick M, Paradkar PN. Parkin regulates metal transport via proteasomal degradation of the 1B isoforms of divalent metal transporter 1. J Neurochem 2010; 113:454-64. [PMID: 20089134 DOI: 10.1111/j.1471-4159.2010.06607.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Abnormal iron accumulation is linked to a variety of neurological disorders and may contribute to the progressive damage seen in these diseases. The biochemical processes responsible for iron accumulation are not known but are likely to entail alteration in transport into injured brain areas. The major transport protein responsible for uptake of iron is divalent metal transporter 1 (DMT1) and recent studies demonstrate that the 1B species is regulated post-translationally by degradation via the proteasomal pathway. As reported in this paper, the E3 ligase, parkin, when over-expressed in SH-SY5Y cells, results in a decrease in 1B-DMT1 isoforms and also a significant reduction in manganese transport and toxicity. Incubating cells over-expressing parkin with the proteasomal inhibitor, MG-132, restores 1B-DMT1 levels emphasizing that the observed changes are caused by degradation via the proteasomal pathway. Expression of the 1B species of DMT1 was also shown to be elevated in human lymphocytes containing a homozygous deletion of exon 4 of parkin and in brains of parkin knockout animals. Immunoprecipitation and immunofluorescent studies confirm that parkin co-localizes with DMT1 in SH-SY5Y cells transfected with wild-type parkin. These results demonstrate that parkin is the E3 ligase responsible for ubiquitination of the 1B species of DMT1.
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Affiliation(s)
- Jerome A Roth
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14214, USA.
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Abstract
Prions are responsible for a heterogeneous group of fatal neurodegenerative diseases. They can be sporadic, genetic, or infectious disorders involving post-translational modifications of the cellular prion protein (PrP(C)). Prions (PrP(Sc)) are characterized by their infectious property and intrinsic ability to convert the physiological PrP(C) into the pathological form, acting as a template. The "protein-only" hypothesis, postulated by Stanley B. Prusiner, implies the possibility to generate de novo prions in vivo and in vitro. Here we describe major milestones towards proving this hypothesis, taking into account physiological environment/s, biochemical properties and interactors of the PrP(C).
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Affiliation(s)
- Federico Benetti
- Laboratory of Prion Biology, Neurobiology Sector, Scuola Internazionale Superiore di Studi Avanzati-International School of Advanced Studies (SISSA-ISAS), Basovizza (TS), Italy
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Prion metal interaction: Is prion pathogenesis a cause or a consequence of metal imbalance? Chem Biol Interact 2009; 181:282-91. [PMID: 19660443 DOI: 10.1016/j.cbi.2009.07.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 07/22/2009] [Accepted: 07/27/2009] [Indexed: 12/14/2022]
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Singh N, Das D, Singh A, Mohan ML. Prion protein and metal interaction: physiological and pathological implications. Curr Issues Mol Biol 2009; 12:99-107. [PMID: 19767653 PMCID: PMC8284910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023] Open
Abstract
Metal induced free radicals are important mediators of neurotoxicity in several neurodegenerative conditions such as Alzheimer's disease, Parkinson's disease, and Huntington's disease. Similar evidence is now emerging for prion diseases, a group of neurodegenerative disorders of humans and animals. The main pathogenic agent in all prion disorders is PrP-scrapie (PrP(Sc)), a beta-sheet rich isoform of a normal cell surface glycoprotein known as the prion protein (PrP(C)). Deposits of PrP(Sc) in the brain parenchyma are believed to induce neurotoxicity through poorly understood mechanisms. Recent reports suggest that imbalance of brain metal homeostasis is a significant cause of PrP(Sc)-associated neurotoxicity, though the underlying mechanisms are difficult to explain based on existing information. Proposed hypotheses include a functional role for PrP(C) in metal metabolism, and loss of this function due to aggregation to the disease associated PrP(Sc) form as the cause of brain metal imbalance. Other views suggest gain of toxic function by PrP(Sc) due to sequestration of PrP(C)-associated metals within the aggregates, resulting in the generation of redox-active PrP(Sc) complexes. The physiological implications of some PrP(C)-metal interactions are known, while others are still unclear. The pathological implications of PrP(C)-metal interaction include metal-induced oxidative damage, and in some instances conversion of PrP(C) to a PrP(Sc)-like form. Despite its significance, only limited information is available on PrP-metal interaction and its implications on prion disease pathogenesis. In this review, we summarize the physiological significance and pathological implications of PrP-metal interaction on prion disease pathogenesis.
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Affiliation(s)
- Neena Singh
- The Department of Pathology, Case Western Reserve University, 2103, Cornell Road, Cleveland, Ohio 44106, USA.
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Giorgi A, Di Francesco L, Principe S, Mignogna G, Sennels L, Mancone C, Alonzi T, Sbriccoli M, De Pascalis A, Rappsilber J, Cardone F, Pocchiari M, Maras B, Schininà ME. Proteomic profiling of PrP27-30-enriched preparations extracted from the brain of hamsters with experimental scrapie. Proteomics 2009; 9:3802-14. [DOI: 10.1002/pmic.200900085] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Singh A, Kong Q, Luo X, Petersen RB, Meyerson H, Singh N. Prion protein (PrP) knock-out mice show altered iron metabolism: a functional role for PrP in iron uptake and transport. PLoS One 2009; 4:e6115. [PMID: 19568430 PMCID: PMC2699477 DOI: 10.1371/journal.pone.0006115] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Accepted: 05/20/2009] [Indexed: 11/23/2022] Open
Abstract
Despite overwhelming evidence implicating the prion protein (PrP) in prion disease pathogenesis, the normal function of this cell surface glycoprotein remains unclear. In previous reports we demonstrated that PrP mediates cellular iron uptake and transport, and aggregation of PrP to the disease causing PrP-scrapie (PrPSc) form results in imbalance of iron homeostasis in prion disease affected human and animal brains. Here, we show that selective deletion of PrP in transgenic mice (PrPKO) alters systemic iron homeostasis as reflected in hematological parameters and levels of total iron and iron regulatory proteins in the plasma, liver, spleen, and brain of PrPKO mice relative to matched wild type controls. Introduction of radiolabeled iron (59FeCl3) to Wt and PrPKO mice by gastric gavage reveals inefficient transport of 59Fe from the duodenum to the blood stream, an early abortive spike of erythropoiesis in the long bones and spleen, and eventual decreased 59Fe content in red blood cells and all major organs of PrPKO mice relative to Wt controls. The iron deficient phenotype of PrPKO mice is reversed by expressing Wt PrP in the PrPKO background, demonstrating a functional role for PrP in iron uptake and transport. Since iron is required for essential metabolic processes and is also potentially toxic if mismanaged, these results suggest that loss of normal function of PrP due to aggregation to the PrPSc form induces imbalance of brain iron homeostasis, resulting in disease associated neurotoxicity.
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Affiliation(s)
- Ajay Singh
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Qingzhong Kong
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Xiu Luo
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Robert B. Petersen
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Howard Meyerson
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Neena Singh
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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Hwang D, Lee IY, Yoo H, Gehlenborg N, Cho JH, Petritis B, Baxter D, Pitstick R, Young R, Spicer D, Price ND, Hohmann JG, Dearmond SJ, Carlson GA, Hood LE. A systems approach to prion disease. Mol Syst Biol 2009; 5:252. [PMID: 19308092 PMCID: PMC2671916 DOI: 10.1038/msb.2009.10] [Citation(s) in RCA: 211] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Accepted: 01/20/2009] [Indexed: 01/10/2023] Open
Abstract
Prions cause transmissible neurodegenerative diseases and replicate by conformational conversion of normal benign forms of prion protein (PrPC) to disease-causing PrPSc isoforms. A systems approach to disease postulates that disease arises from perturbation of biological networks in the relevant organ. We tracked global gene expression in the brains of eight distinct mouse strain–prion strain combinations throughout the progression of the disease to capture the effects of prion strain, host genetics, and PrP concentration on disease incubation time. Subtractive analyses exploiting various aspects of prion biology and infection identified a core of 333 differentially expressed genes (DEGs) that appeared central to prion disease. DEGs were mapped into functional pathways and networks reflecting defined neuropathological events and PrPSc replication and accumulation, enabling the identification of novel modules and modules that may be involved in genetic effects on incubation time and in prion strain specificity. Our systems analysis provides a comprehensive basis for developing models for prion replication and disease, and suggests some possible therapeutic approaches.
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Affiliation(s)
- Daehee Hwang
- Institute for Systems Biology, Seattle, WA 98103, USA
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Singh A, Isaac AO, Luo X, Mohan ML, Cohen ML, Chen F, Kong Q, Bartz J, Singh N. Abnormal brain iron homeostasis in human and animal prion disorders. PLoS Pathog 2009; 5:e1000336. [PMID: 19283067 PMCID: PMC2652663 DOI: 10.1371/journal.ppat.1000336] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Accepted: 02/12/2009] [Indexed: 11/18/2022] Open
Abstract
Neurotoxicity in all prion disorders is believed to result from the accumulation of PrP-scrapie (PrP(Sc)), a beta-sheet rich isoform of a normal cell-surface glycoprotein, the prion protein (PrP(C)). Limited reports suggest imbalance of brain iron homeostasis as a significant associated cause of neurotoxicity in prion-infected cell and mouse models. However, systematic studies on the generality of this phenomenon and the underlying mechanism(s) leading to iron dyshomeostasis in diseased brains are lacking. In this report, we demonstrate that prion disease-affected human, hamster, and mouse brains show increased total and redox-active Fe (II) iron, and a paradoxical increase in major iron uptake proteins transferrin (Tf) and transferrin receptor (TfR) at the end stage of disease. Furthermore, examination of scrapie-inoculated hamster brains at different timepoints following infection shows increased levels of Tf with time, suggesting increasing iron deficiency with disease progression. Sporadic Creutzfeldt-Jakob disease (sCJD)-affected human brains show a similar increase in total iron and a direct correlation between PrP and Tf levels, implicating PrP(Sc) as the underlying cause of iron deficiency. Increased binding of Tf to the cerebellar Purkinje cell neurons of sCJD brains further indicates upregulation of TfR and a phenotype of neuronal iron deficiency in diseased brains despite increased iron levels. The likely cause of this phenotype is sequestration of iron in brain ferritin that becomes detergent-insoluble in PrP(Sc)-infected cell lines and sCJD brain homogenates. These results suggest that sequestration of iron in PrP(Sc)-ferritin complexes induces a state of iron bio-insufficiency in prion disease-affected brains, resulting in increased uptake and a state of iron dyshomeostasis. An additional unexpected observation is the resistance of Tf to digestion by proteinase-K, providing a reliable marker for iron levels in postmortem human brains. These data implicate redox-iron in prion disease-associated neurotoxicity, a novel observation with significant implications for prion disease pathogenesis.
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Affiliation(s)
- Ajay Singh
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Alfred Orina Isaac
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Xiu Luo
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Maradumane L. Mohan
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Mark L. Cohen
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Fusong Chen
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Qingzhong Kong
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Jason Bartz
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| | - Neena Singh
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
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Singh A, Mohan ML, Isaac AO, Luo X, Petrak J, Vyoral D, Singh N. Prion protein modulates cellular iron uptake: a novel function with implications for prion disease pathogenesis. PLoS One 2009; 4:e4468. [PMID: 19212444 PMCID: PMC2637434 DOI: 10.1371/journal.pone.0004468] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2008] [Accepted: 12/26/2008] [Indexed: 01/18/2023] Open
Abstract
Converging evidence leaves little doubt that a change in the conformation of prion protein (PrPC) from a mainly α-helical to a β-sheet rich PrP-scrapie (PrPSc) form is the main event responsible for prion disease associated neurotoxicity. However, neither the mechanism of toxicity by PrPSc, nor the normal function of PrPC is entirely clear. Recent reports suggest that imbalance of iron homeostasis is a common feature of prion infected cells and mouse models, implicating redox-iron in prion disease pathogenesis. In this report, we provide evidence that PrPC mediates cellular iron uptake and transport, and mutant PrP forms alter cellular iron levels differentially. Using human neuroblastoma cells as models, we demonstrate that over-expression of PrPC increases intra-cellular iron relative to non-transfected controls as indicated by an increase in total cellular iron, the cellular labile iron pool (LIP), and iron content of ferritin. As a result, the levels of iron uptake proteins transferrin (Tf) and transferrin receptor (TfR) are decreased, and expression of iron storage protein ferritin is increased. The positive effect of PrPC on ferritin iron content is enhanced by stimulating PrPC endocytosis, and reversed by cross-linking PrPC on the plasma membrane. Expression of mutant PrP forms lacking the octapeptide-repeats, the membrane anchor, or carrying the pathogenic mutation PrP102L decreases ferritin iron content significantly relative to PrPC expressing cells, but the effect on cellular LIP and levels of Tf, TfR, and ferritin is complex, varying with the mutation. Neither PrPC nor the mutant PrP forms influence the rate or amount of iron released into the medium, suggesting a functional role for PrPC in cellular iron uptake and transport to ferritin, and dysfunction of PrPC as a significant contributing factor of brain iron imbalance in prion disorders.
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Affiliation(s)
- Ajay Singh
- The Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Maradumane L. Mohan
- The Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Alfred Orina Isaac
- The Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Xiu Luo
- The Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Jiri Petrak
- Department of Pathological Physiology, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic
| | - Daniel Vyoral
- Department of Pathological Physiology, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic
| | - Neena Singh
- The Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail: .
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Kell DB. Iron behaving badly: inappropriate iron chelation as a major contributor to the aetiology of vascular and other progressive inflammatory and degenerative diseases. BMC Med Genomics 2009; 2:2. [PMID: 19133145 PMCID: PMC2672098 DOI: 10.1186/1755-8794-2-2] [Citation(s) in RCA: 364] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Accepted: 01/08/2009] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular 'reactive oxygen species' (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. REVIEW We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation).The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible.This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, since in some circumstances (especially the presence of poorly liganded iron) molecules that are nominally antioxidants can actually act as pro-oxidants. The reduction of redox stress thus requires suitable levels of both antioxidants and effective iron chelators. Some polyphenolic antioxidants may serve both roles.Understanding the exact speciation and liganding of iron in all its states is thus crucial to separating its various pro- and anti-inflammatory activities. Redox stress, innate immunity and pro- (and some anti-)inflammatory cytokines are linked in particular via signalling pathways involving NF-kappaB and p38, with the oxidative roles of iron here seemingly involved upstream of the IkappaB kinase (IKK) reaction. In a number of cases it is possible to identify mechanisms by which ROSs and poorly liganded iron act synergistically and autocatalytically, leading to 'runaway' reactions that are hard to control unless one tackles multiple sites of action simultaneously. Some molecules such as statins and erythropoietin, not traditionally associated with anti-inflammatory activity, do indeed have 'pleiotropic' anti-inflammatory effects that may be of benefit here. CONCLUSION Overall we argue, by synthesising a widely dispersed literature, that the role of poorly liganded iron has been rather underappreciated in the past, and that in combination with peroxide and superoxide its activity underpins the behaviour of a great many physiological processes that degrade over time. Understanding these requires an integrative, systems-level approach that may lead to novel therapeutic targets.
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Affiliation(s)
- Douglas B Kell
- School of Chemistry and Manchester Interdisciplinary Biocentre, The University of Manchester, 131 Princess St, Manchester, M1 7DN, UK.
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Pamplona R, Naudí A, Gavín R, Pastrana MA, Sajnani G, Ilieva EV, Del Río JA, Portero-Otín M, Ferrer I, Requena JR. Increased oxidation, glycoxidation, and lipoxidation of brain proteins in prion disease. Free Radic Biol Med 2008; 45:1159-66. [PMID: 18703134 DOI: 10.1016/j.freeradbiomed.2008.07.009] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Revised: 07/09/2008] [Accepted: 07/11/2008] [Indexed: 02/02/2023]
Abstract
The basic molecular underpinnings of the pathological changes that unfold in prion disease remain elusive. A key role of increased oxidative stress has been hypothesized. Given the transient nature of most intermediate molecules implicated, increased oxidative stress is better assessed by quantitating the damage it causes to macromolecules. We used mass spectrometry-based methods to measure specific products of protein oxidation, glycoxidation, and lipoxidation in brains from patients suffering from Creutzfeldt-Jakob disease and Syrian hamsters affected by scrapie. In both cases, increased amounts of glutamic and aminoadipic semialdehydes, products of metal-catalyzed oxidation, malondialdehydelysine (a product of lipoxidation), N-epsilon-carboxyethyllysine (a product of glycoxidation), and N-epsilon-carboxymethyllysine (generated by lipoxidation and glycoxidation) were measured. PrP(Sc), the infectious isoform of the prion protein that accumulates in prion disease, was itself shown to be a target of increased oxidative modification. These changes were accompanied by alterations in fatty acid composition and increased phosphorylation of ERK(1/2) and p38, protein kinases known to respond to increased flows of ROS. These data support an important role of oxidative damage in the pathology of prion disease.
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Affiliation(s)
- Reinald Pamplona
- Metabolic Pathophysiology Research Group, Departament de Medicina Experimental, Universitat de Lleida-IRBLLEIDA, Lleida 25008, Catalonia, Spain
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The effect of Fenton reaction on protease-resistant prion protein (PrPSc) degradation and scrapie infectivity. Brain Res 2008; 1238:172-80. [DOI: 10.1016/j.brainres.2008.07.117] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Revised: 07/30/2008] [Accepted: 07/30/2008] [Indexed: 11/17/2022]
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Lee KS, Raymond LD, Schoen B, Raymond GJ, Kett L, Moore RA, Johnson LM, Taubner L, Speare JO, Onwubiko HA, Baron GS, Caughey WS, Caughey B. Hemin Interactions and Alterations of the Subcellular Localization of Prion Protein. J Biol Chem 2007; 282:36525-33. [DOI: 10.1074/jbc.m705620200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Lupi O, Peryassu MA. An emerging concept of prion infections as a form of transmissible cerebral amyloidosis. Prion 2007; 1:223-7. [PMID: 19172115 DOI: 10.4161/pri.1.4.5816] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Proteins are a major constituent of cells with specific biological functions. Besides the primary structure that is simply the sequence of amino acids that comprise a protein, the secondary structure represents the first step of folding defining its general conformation. The biological functions of proteins are directly dependent on the acquisition of their conformation. The same protein can have different stable states, which may participate with different functions in the cell. The amyloid diseases comprise Alzheimer's and Parkinson's diseases, type II diabetes mellitus and systemic amyloidosis. Amyloid fibers are insoluble, resistant to proteolysis and show an extremely high content of beta-sheet, in a very similar structure to the one observed among prion rods, associated to the transmissible spongiform encephalopathies. All these diseases are "infectious" in the sense that misfolded beta-sheeted conformers formed in a nucleation process in which preformed metastable oligomer acts as a seed to convert a normal isoform into an abnormal protein with a misfolded conformation. Only prion infections have a proven infectivity in a microbiological sense; some recent observations, however, detected the transmissibility of systemic amyloidosis by a prion-like mechanism among mice. Prions diseases and amyloidosis present many similar aspects of the so-called conformational diseases; according to this interpretation the prion infections could be considered as a form of transmissible cerebral amyloidosis.
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Affiliation(s)
- Omar Lupi
- Department of Dermatology, Universidade Federal do Estado do Rio de Janerio, Rio de Janeiro, Brazil.
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