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Benarroch E. What Are the Roles of Cellular Prion Protein in Normal and Pathologic Conditions? Neurology 2024; 102:e209272. [PMID: 38484222 DOI: 10.1212/wnl.0000000000209272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 01/11/2024] [Indexed: 03/19/2024] Open
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2
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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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3
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Steinert JR, Amal H. The contribution of an imbalanced redox signalling to neurological and neurodegenerative conditions. Free Radic Biol Med 2023; 194:71-83. [PMID: 36435368 DOI: 10.1016/j.freeradbiomed.2022.11.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/17/2022] [Accepted: 11/22/2022] [Indexed: 11/25/2022]
Abstract
Nitric oxide and other redox active molecules such as oxygen free radicals provide essential signalling in diverse neuronal functions, but their excess production and insufficient scavenging induces cytotoxic redox stress which is associated with numerous neurodegenerative and neurological conditions. A further component of redox signalling is mediated by a homeostatic regulation of divalent metal ions, the imbalance of which contributes to neuronal dysfunction. Additional antioxidant molecules such as glutathione and enzymes such as super oxide dismutase are involved in maintaining a physiological redox status within neurons. When cellular processes are perturbed and generation of free radicals overwhelms the antioxidants capacity of the neurons, a resulting redox damage leads to neuronal dysfunction and cell death. Cellular sources for production of redox-active molecules may include NADPH oxidases, mitochondria, cytochrome P450 and nitric oxide (NO)-generating enzymes, such as endothelial, neuronal and inducible NO synthases. Several neurodegenerative and developmental neurological conditions are associated with an imbalanced redox state as a result of neuroinflammatory processes leading to nitrosative and oxidative stress. Ongoing research aims at understanding the causes and consequences of such imbalanced redox homeostasis and its role in neuronal dysfunction.
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Affiliation(s)
- Joern R Steinert
- Division of Physiology, Pharmacology and Neuroscience, University of Nottingham, School of Life Sciences, Nottingham, NG7 2NR, UK.
| | - Haitham Amal
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
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4
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Shafiq M, Da Vela S, Amin L, Younas N, Harris DA, Zerr I, Altmeppen HC, Svergun D, Glatzel M. The prion protein and its ligands: Insights into structure-function relationships. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119240. [PMID: 35192891 DOI: 10.1016/j.bbamcr.2022.119240] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 01/23/2022] [Accepted: 01/28/2022] [Indexed: 06/14/2023]
Abstract
The prion protein is a multifunctional protein that exists in at least two different folding states. It is subject to diverse proteolytic processing steps that lead to prion protein fragments some of which are membrane-bound whereas others are soluble. A multitude of ligands bind to the prion protein and besides proteinaceous binding partners, interaction with metal ions and nucleic acids occurs. Although of great importance, information on structural and functional consequences of prion protein binding to its partners is limited. Here, we will reflect on the structure-function relationship of the prion protein and its binding partners considering the different folding states and prion protein fragments.
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Affiliation(s)
- Mohsin Shafiq
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20251 Hamburg, Germany
| | - Stefano Da Vela
- European Molecular Biology Laboratory (EMBL), Hamburg c/o German Electron Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany
| | - Ladan Amin
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, United States
| | - Neelam Younas
- Department of Neurology, University Medical Center Goettingen, Robert-Koch-str. 40, 37075 Goettingen, Germany
| | - David A Harris
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, United States
| | - Inga Zerr
- Department of Neurology, University Medical Center Goettingen, Robert-Koch-str. 40, 37075 Goettingen, Germany
| | - Hermann C Altmeppen
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20251 Hamburg, Germany
| | - Dmitri Svergun
- European Molecular Biology Laboratory (EMBL), Hamburg c/o German Electron Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany
| | - Markus Glatzel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20251 Hamburg, Germany.
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5
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Pushie MJ, Sylvain NJ, Hou H, Hackett MJ, Kelly ME, Webb SM. X-ray Fluorescence Microscopy Methods for Biological Tissues. Metallomics 2022; 14:6581349. [PMID: 35512669 PMCID: PMC9226457 DOI: 10.1093/mtomcs/mfac032] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Accepted: 05/05/2022] [Indexed: 11/14/2022]
Abstract
Synchrotron-based X-ray fluorescence microscopy is a flexible tool for identifying the distribution of trace elements in biological specimens across a broad range of sample sizes. The technique is not particularly limited by sample type and can be performed on ancient fossils, fixed or fresh tissue specimens, and in some cases even live tissue and live cells can be studied. The technique can also be expanded to provide chemical specificity to elemental maps, either at individual points of interest in a map or across a large field of view. While virtually any sample type can be characterized with X-ray fluorescence microscopy, common biological sample preparation methods (often borrowed from other fields, such as histology) can lead to unforeseen pitfalls, resulting in altered element distributions and concentrations. A general overview of sample preparation and data acquisition methods for X-ray fluorescence microscopy is presented, along with outlining the general approach for applying this technique to a new field of investigation for prospective new-users. Considerations for improving data acquisition and quality are reviewed as well as the effects of sample preparation, with a particular focus on soft tissues. The effects of common sample pre-treatment steps as well as the underlying factors that govern which, and to what extent, specific elements are likely to be altered are reviewed along with common artifacts observed in X-ray fluorescence microscopy data.
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Affiliation(s)
- M Jake Pushie
- Department of Surgery, Division of Neurosurgery, College of Medicine, University of Saskatchewan, Saskatoon, SK, S7N 5E5Canada
| | - Nicole J Sylvain
- Department of Surgery, Division of Neurosurgery, College of Medicine, University of Saskatchewan, Saskatoon, SK, S7N 5E5Canada.,Clinical Trial Support Unit, College of Medicine, University of Saskatchewan, Saskatoon, SK, S7N 0W8Canada
| | - Huishu Hou
- Department of Surgery, Division of Neurosurgery, College of Medicine, University of Saskatchewan, Saskatoon, SK, S7N 5E5Canada
| | - Mark J Hackett
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA 6102, AUS.,School of Molecular and Life Sciences, Curtin University, Perth, WA 6845, AUS
| | - Michael E Kelly
- Department of Surgery, Division of Neurosurgery, College of Medicine, University of Saskatchewan, Saskatoon, SK, S7N 5E5Canada
| | - Samuel M Webb
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
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6
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Loh D, Reiter RJ. Melatonin: Regulation of Prion Protein Phase Separation in Cancer Multidrug Resistance. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27030705. [PMID: 35163973 PMCID: PMC8839844 DOI: 10.3390/molecules27030705] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/11/2022] [Accepted: 01/17/2022] [Indexed: 12/13/2022]
Abstract
The unique ability to adapt and thrive in inhospitable, stressful tumor microenvironments (TME) also renders cancer cells resistant to traditional chemotherapeutic treatments and/or novel pharmaceuticals. Cancer cells exhibit extensive metabolic alterations involving hypoxia, accelerated glycolysis, oxidative stress, and increased extracellular ATP that may activate ancient, conserved prion adaptive response strategies that exacerbate multidrug resistance (MDR) by exploiting cellular stress to increase cancer metastatic potential and stemness, balance proliferation and differentiation, and amplify resistance to apoptosis. The regulation of prions in MDR is further complicated by important, putative physiological functions of ligand-binding and signal transduction. Melatonin is capable of both enhancing physiological functions and inhibiting oncogenic properties of prion proteins. Through regulation of phase separation of the prion N-terminal domain which targets and interacts with lipid rafts, melatonin may prevent conformational changes that can result in aggregation and/or conversion to pathological, infectious isoforms. As a cancer therapy adjuvant, melatonin could modulate TME oxidative stress levels and hypoxia, reverse pH gradient changes, reduce lipid peroxidation, and protect lipid raft compositions to suppress prion-mediated, non-Mendelian, heritable, but often reversible epigenetic adaptations that facilitate cancer heterogeneity, stemness, metastasis, and drug resistance. This review examines some of the mechanisms that may balance physiological and pathological effects of prions and prion-like proteins achieved through the synergistic use of melatonin to ameliorate MDR, which remains a challenge in cancer treatment.
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Affiliation(s)
- Doris Loh
- Independent Researcher, Marble Falls, TX 78654, USA
- Correspondence: (D.L.); (R.J.R.)
| | - Russel J. Reiter
- Department of Cellular and Structural Biology, UT Health San Antonio, San Antonio, TX 78229, USA
- Correspondence: (D.L.); (R.J.R.)
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7
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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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Chaudhary S, Ashok A, McDonald D, Wise AS, Kritikos AE, Rana NA, Harding CV, Singh N. Upregulation of Local Hepcidin Contributes to Iron Accumulation in Alzheimer's Disease Brains. J Alzheimers Dis 2021; 82:1487-1497. [PMID: 34180415 DOI: 10.3233/jad-210221] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Accumulation of iron is a consistent feature of Alzheimer's disease (AD) brains. The underlying cause, however, remains debatable. OBJECTIVE To explore whether local hepcidin synthesized by brain cells contributes to iron accumulation in AD brains. METHODS Brain tissue from the cingulate cortex of 33 cases of AD pre-assigned to Braak stage I-VI, 6 cases of non-dementia, and 15 cases of non-AD dementia were analyzed for transcriptional upregulation of hepcidin by RT-qPCR and RT-PCR. Change in the expression of ferritin, ferroportin (Fpn), microglial activation marker Iba1, IL-6, and TGFβ2 was determined by western blotting. Total tissue iron was determined by colorimetry. RESULTS Significant transcriptional upregulation of hepcidin was observed in Braak stage III-VI relative to Braak stage I and II, non-AD dementia, and non-dementia samples. Ferritin was increased in Braak stage V, and a significant increase in tissue iron was evident in Braak stage III-VI. The expression of Iba1 and IL-6 was also increased in Braak stage III-VI relative to Braak stage I and II and non-AD dementia samples. Amyloid-β plaques were absent in most Braak stage I and II samples, and present in Braak stage III-VI samples with few exceptions. CONCLUSION These observations suggest that upregulation of brain hepcidin is mediated by IL-6, a known transcriptional activator of hepcidin. The consequent downregulation of Fpn on neuronal and other cells results in accumulation of iron in AD brains. The increase in hepcidin is disease-specific, and increases with disease progression, implicating AD-specific pathology in the accumulation of iron.
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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
| | - Dallas McDonald
- 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
| | - Alexander E Kritikos
- 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
| | - Clifford V Harding
- 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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9
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Singh N, Chaudhary S, Ashok A, Lindner E. Prions and prion diseases: Insights from the eye. Exp Eye Res 2020; 199:108200. [PMID: 32858007 DOI: 10.1016/j.exer.2020.108200] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 07/24/2020] [Accepted: 08/21/2020] [Indexed: 12/30/2022]
Abstract
Prion diseases are invariably fatal neurodegenerative disorders that have gained much publicity due to their transmissible nature. Sporadic Creutzfeldt-Jakob disease (sCJD) is the most common human prion disorder, with an incidence of 1 in a million. Inherited prion disorders are relatively rare, and associated with mutations in the prion protein gene. More than 50 different point mutations, deletions, and insertions have been identified so far. Most are autosomal dominant and fully penetrant. Prion disorders also occur in animals, and are of major concern because of the potential for spreading to humans. The principal pathogenic event underlying all prion disorders is a change in the conformation of prion protein (PrPC) from a mainly α-helical to a β-sheet rich isoform, PrP-scrapie (PrPSc). Accumulation of PrPSc in the brain parenchyma is the major cause of neuronal degeneration. The mechanism by which PrPSc is transmitted, propagates, and causes neurodegenerative changes has been investigated over the years, and several clues have emerged. Efforts are also ongoing for identifying specific and sensitive diagnostic tests for sCJD and animal prion disorders, but success has been limited. The eye is suitable for these evaluations because it shares several anatomical and physiological features with the brain, and can be observed in vivo during disease progression. The retina, considered an extension of the central nervous system, is involved extensively in prion disorders. Accordingly, Optical Coherence Tomography and electroretinogram have shown some promise as pre-mortem diagnostic tests for human and animal prion disorders. However, a complete understanding of the physiology of PrPC and pathobiology of PrPSc in the eye is essential for developing specific and sensitive tests. Below, we summarize recent progress in ocular physiology and pathology in prion disorders, and the eye as an anatomically accessible site to diagnose, monitor disease progression, and test therapeutic options.
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Affiliation(s)
- Neena Singh
- Departments of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA.
| | - Suman Chaudhary
- Departments of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Ajay Ashok
- Departments of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Ewald Lindner
- Department of Ophthalmology, Medical University of Graz, Auenbruggerplatz 4, 8036, Graz, Austria
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11
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Abstract
Complex diseases involve dynamic perturbations of pathophysiological processes during disease progression. Transcriptional programs underlying such perturbations are unknown in many diseases. Here, we present core transcriptional regulatory circuits underlying early and late perturbations in prion disease. We first identified cellular processes perturbed early and late using time-course gene expression data from three prion-infected mouse strains. We then built a transcriptional regulatory network (TRN) describing regulation of early and late processes. We found over-represented feed-forward loops (FFLs) comprising transcription factor (TF) pairs and target genes in the TRN. Using gene expression data of brain cell types, we further selected active FFLs where TF pairs and target genes were expressed in the same cell type and showed correlated temporal expression changes in the brain. We finally determined core transcriptional regulatory circuits by combining these active FFLs. These circuits provide insights into transcriptional programs for early and late pathophysiological processes in prion disease.
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12
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Nakagawa Y, Yamada S. Metal homeostasis disturbances in neurodegenerative disorders, with special emphasis on Creutzfeldt-Jakob disease - Potential pathogenetic mechanism and therapeutic implications. Pharmacol Ther 2019; 207:107455. [PMID: 31863817 DOI: 10.1016/j.pharmthera.2019.107455] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 12/09/2019] [Indexed: 12/14/2022]
Abstract
Creutzfeldt-Jakob disease (CJD) is characterized by a rapidly progressive dementia often accompanied by myoclonus and other signs of brain dysfunction, relying on the conversion of the normal cellular form of the prion protein (PrPC) to a misfolded form (PrPSc). The neuropathological changes include spongiform degeneration, neuronal loss, astrogliosis, and deposition of PrPSc. It is still unclear how these pathological changes correlate with the development of CJD symptoms because few patients survive beyond 2 years after diagnosis. Inasmuch as the symptoms of CJD overlap some of those observed in Alzheimer's, Parkinson's, and Huntington's diseases, there may be some underlying pathologic mechanisms associated with CJD that may contribute to the symptoms of non-prion neurodegenerative diseases as well. Data suggest that imbalance of metals, including copper, zinc, iron, and manganese, induces abnormalities in processing and degradation of prion proteins that are accompanied by self-propagation of PrPSc. These events appear to be responsible for glutamatergic synaptic dysfunctions, neuronal death, and PrPSc aggregation. Given that the prodromal symptoms of CJD such as sleep disturbances and mood disorders are associated with brain stem and limbic system dysfunction, the pathological changes may initially occur in these brain regions, then spread throughout the entire brain. Alterations in cerebrospinal fluid homeostasis, which may be linked to imbalance of these metals, seem to be more important than neuroinflammation in causing the cell death. It is proposed that metal dyshomeostasis could be responsible for the initiation and progression of the pathological changes associated with symptoms of CJD and other neurodegenerative disorders.
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Affiliation(s)
- Yutaka Nakagawa
- Center for Pharma-Food Research (CPFR), Division of Pharmaceutical Sciences, Graduate School of Integrative Pharmaceutical and Nutritional Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
| | - Shizuo Yamada
- Center for Pharma-Food Research (CPFR), Division of Pharmaceutical Sciences, Graduate School of Integrative Pharmaceutical and Nutritional Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
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Structural Consequences of Copper Binding to the Prion Protein. Cells 2019; 8:cells8080770. [PMID: 31349611 PMCID: PMC6721516 DOI: 10.3390/cells8080770] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 07/22/2019] [Accepted: 07/23/2019] [Indexed: 12/24/2022] Open
Abstract
Prion, or PrPSc, is the pathological isoform of the cellular prion protein (PrPC) and it is the etiological agent of transmissible spongiform encephalopathies (TSE) affecting humans and animal species. The most relevant function of PrPC is its ability to bind copper ions through its flexible N-terminal moiety. This review includes an overview of the structure and function of PrPC with a focus on its ability to bind copper ions. The state-of-the-art of the role of copper in both PrPC physiology and in prion pathogenesis is also discussed. Finally, we describe the structural consequences of copper binding to the PrPC structure.
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Joppe K, Roser AE, Maass F, Lingor P. The Contribution of Iron to Protein Aggregation Disorders in the Central Nervous System. Front Neurosci 2019; 13:15. [PMID: 30723395 PMCID: PMC6350163 DOI: 10.3389/fnins.2019.00015] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 01/08/2019] [Indexed: 01/01/2023] Open
Abstract
The homeostasis of iron is of fundamental importance in the central nervous system (CNS) to ensure biological processes such as oxygen transport, mitochondrial respiration or myelin synthesis. Dyshomeostasis and accumulation of iron can be observed during aging and both are shared characteristics of several neurodegenerative diseases. Iron-mediated generation of reactive oxygen species (ROS) may lead to protein aggregation and cellular toxicity. The process of misfolding and aggregation of neuronal proteins such as α-synuclein, Tau, amyloid beta (Aβ), TDP-43 or SOD1 is a common hallmark of many neurodegenerative disorders and iron has been shown to facilitate protein aggregation. Thus, both, iron and aggregating proteins are proposed to amplify their detrimental effects in the disease state. In this review, we give an overview on effects of iron on aggregation of different proteins involved in neurodegeneration. Furthermore, we discuss the proposed mechanisms of iron-mediated toxicity and protein aggregation emphasizing the red-ox chemistry and protein-binding properties of iron. Finally, we address current therapeutic approaches harnessing iron chelation as a disease-modifying intervention in neurodegenerative disorders, such as Parkinson’s disease, Alzheimer’s disease, and amyotrophic lateral sclerosis.
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Affiliation(s)
- Karina Joppe
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Anna-Elisa Roser
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Fabian Maass
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Paul Lingor
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany.,Center for Biostructural Imaging of Neurodegeneration, Göttingen, Germany.,German Center for Neurodegenerative Diseases, Göttingen, Germany.,Rechts der Isar Hospital, Technical University of Munich, Munich, Germany
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15
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Sfera A, Gradini R, Cummings M, Diaz E, Price AI, Osorio C. Rusty Microglia: Trainers of Innate Immunity in Alzheimer's Disease. Front Neurol 2018; 9:1062. [PMID: 30564191 PMCID: PMC6288235 DOI: 10.3389/fneur.2018.01062] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 11/21/2018] [Indexed: 12/15/2022] Open
Abstract
Alzheimer's disease, the most common form of dementia, is marked by progressive cognitive and functional impairment believed to reflect synaptic and neuronal loss. Recent preclinical data suggests that lipopolysaccharide (LPS)-activated microglia may contribute to the elimination of viable neurons and synapses by promoting a neurotoxic astrocytic phenotype, defined as A1. The innate immune cells, including microglia and astrocytes, can either facilitate or inhibit neuroinflammation in response to peripherally applied inflammatory stimuli, such as LPS. Depending on previous antigen encounters, these cells can assume activated (trained) or silenced (tolerized) phenotypes, augmenting or lowering inflammation. Iron, reactive oxygen species (ROS), and LPS, the cell wall component of gram-negative bacteria, are microglial activators, but only the latter can trigger immune tolerization. In Alzheimer's disease, tolerization may be impaired as elevated LPS levels, reported in this condition, fail to lower neuroinflammation. Iron is closely linked to immunity as it plays a key role in immune cells proliferation and maturation, but it is also indispensable to pathogens and malignancies which compete for its capture. Danger signals, including LPS, induce intracellular iron sequestration in innate immune cells to withhold it from pathogens. However, excess cytosolic iron increases the risk of inflammasomes' activation, microglial training and neuroinflammation. Moreover, it was suggested that free iron can awaken the dormant central nervous system (CNS) LPS-shedding microbes, engendering prolonged neuroinflammation that may override immune tolerization, triggering autoimmunity. In this review, we focus on iron-related innate immune pathology in Alzheimer's disease and discuss potential immunotherapeutic agents for microglial de-escalation along with possible delivery vehicles for these compounds.
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Affiliation(s)
- Adonis Sfera
- Psychiatry, Loma Linda University, Loma Linda, CA, United States.,Patton State Hospital, San Bernardino, CA, United States
| | - Roberto Gradini
- Department of Pathology, La Sapienza University of Rome, Rome, Italy
| | | | - Eddie Diaz
- Patton State Hospital, San Bernardino, CA, United States
| | - Amy I Price
- Evidence Based Medicine, University of Oxford, Oxford, United Kingdom
| | - Carolina Osorio
- Psychiatry, Loma Linda University, Loma Linda, CA, United States
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16
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Tripathi AK, Karmakar S, Asthana A, Ashok A, Desai V, Baksi S, Singh N. Transport of Non-Transferrin Bound Iron to the Brain: Implications for Alzheimer's Disease. J Alzheimers Dis 2018; 58:1109-1119. [PMID: 28550259 DOI: 10.3233/jad-170097] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A direct correlation between brain iron and Alzheimer's disease (AD) raises questions regarding the transport of non-transferrin-bound iron (NTBI), a toxic but less researched pool of circulating iron that is likely to increase due to pathological and/or iatrogenic systemic iron overload. Here, we compared the distribution of radiolabeled-NTBI (59Fe-NTBI) and transferrin-bound iron (59Fe-Tf) in mouse models of iron overload in the absence or presence of inflammation. Following a short pulse, most of the 59Fe-NTBI was taken up by the liver, followed by the kidney, pancreas, and heart. Notably, a strong signal of 59Fe-NTBI was detected in the brain ventricular system after 2 h, and the brain parenchyma after 24 h. 59Fe-Tf accumulated mainly in the femur and spleen, and was transported to the brain at a much slower rate than 59Fe-NTBI. In the kidney, 59Fe-NTBI was detected in the cortex after 2 h, and outer medulla after 24 hours. Most of the 59Fe-NTBI and 59Fe-Tf from the kidney was reabsorbed; negligible amount was excreted in the urine. Acute inflammation increased the uptake of 59Fe-NTBI by the kidney and brain from 2-24 hours. Chronic inflammation, on the other hand, resulted in sequestration of iron in the liver and kidney, reducing its transport to the brain. These observations provide direct evidence for the transport of NTBI to the brain, and reveal a complex interplay between inflammation and brain iron homeostasis. Further studies are necessary to determine whether transient increase in NTBI due to systemic iron overload is a risk factor for AD.
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Affiliation(s)
- Ajai K Tripathi
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Shilpita Karmakar
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Abhishek Asthana
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Ajay Ashok
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Vilok Desai
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Shounak Baksi
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Neena Singh
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
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Xiao Y, Chen X, Huang S, Li G, Mo M, Zhang L, Chen C, Guo W, Zhou M, Wu Z, Cen L, Long S, Li S, Yang X, Qu S, Pei Z, Xu P. Iron promotes α-synuclein aggregation and transmission by inhibiting TFEB-mediated autophagosome-lysosome fusion. J Neurochem 2018; 145:34-50. [PMID: 29364516 DOI: 10.1111/jnc.14312] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 01/15/2018] [Accepted: 01/17/2018] [Indexed: 12/21/2022]
Affiliation(s)
- Yousheng Xiao
- Department of Neurology; The First Affiliated Hospital of Guangxi Medical University; Nanning China
- Department of Neurology; National Key Clinical; Department and Key Discipline of Neurology; The First Affiliated Hospital of Sun Yat-sen University; Guangzhou China
| | - Xiang Chen
- Department of Neurology; National Key Clinical; Department and Key Discipline of Neurology; The First Affiliated Hospital of Sun Yat-sen University; Guangzhou China
| | - Shuxuan Huang
- Department of Neurology; The First Affiliated Hospital of Guangzhou Medical University; Guangzhou China
| | - Guihua Li
- Department of Neurology; The First Affiliated Hospital of Guangzhou Medical University; Guangzhou China
| | - Mingshu Mo
- Department of Neurology; The First Affiliated Hospital of Guangzhou Medical University; Guangzhou China
| | - Li Zhang
- Geriatric Neurology Department; Nanjing Brain Hospital; Nanjing Medical University; Nanjing China
| | - Chaojun Chen
- Department of Neurology; Guangzhou Chinese Medical Integrated Hospital (Huadu); Guangzhou China
| | - Wenyuan Guo
- Department of Neurology; The First Affiliated Hospital of Guangzhou Medical University; Guangzhou China
| | - Miaomiao Zhou
- Department of Neurology; The First Affiliated Hospital of Guangzhou Medical University; Guangzhou China
| | - Zhuohua Wu
- Department of Neurology; The First Affiliated Hospital of Guangzhou Medical University; Guangzhou China
| | - Luan Cen
- Department of Neurology; The First Affiliated Hospital of Guangxi Medical University; Nanning China
| | - Simei Long
- Department of Neurology; National Key Clinical; Department and Key Discipline of Neurology; The First Affiliated Hospital of Sun Yat-sen University; Guangzhou China
| | - Shaomin Li
- Ann Romney Center for Neurologic Disease; Brigham and Women's Hospital; Harvard Medical School; Boston MA USA
| | - Xinling Yang
- Department of Neurology; The Second Affiliated Hospital of Xinjiang Medical University; Urumqi China
| | - Shaogang Qu
- Clinical Medicine Research Center; Shunde Hospital; Southern Medical University; Foshan China
| | - Zhong Pei
- Department of Neurology; National Key Clinical; Department and Key Discipline of Neurology; The First Affiliated Hospital of Sun Yat-sen University; Guangzhou China
| | - Pingyi Xu
- Department of Neurology; The First Affiliated Hospital of Guangzhou Medical University; Guangzhou China
- Key Laboratory of Respiratory Disease; The First Affiliated Hospital of Guangzhou Medical University; Guangzhou China
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18
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Abstract
Brain iron is tightly regulated by a multitude of proteins to ensure homeostasis. Iron dyshomeostasis has become a molecular signature associated with aging which is accompanied by progressive decline in cognitive processes. A common theme in neurodegenerative diseases where age is the major risk factor, iron dyshomeostasis coincides with neuroinflammation, abnormal protein aggregation, neurodegeneration, and neurobehavioral deficits. There is a great need to determine the mechanisms governing perturbations in iron metabolism, in particular to distinguish between physiological and pathological aging to generate fruitful therapeutic targets for neurodegenerative diseases. The aim of the present review is to focus on the age-related alterations in brain iron metabolism from a cellular and molecular biology perspective, alongside genetics, and neuroimaging aspects in man and rodent models, with respect to normal aging and neurodegeneration. In particular, the relationship between iron dyshomeostasis and neuroinflammation will be evaluated, as well as the effects of systemic iron overload on the brain. Based on the evidence discussed here, we suggest a synergistic use of iron-chelators and anti-inflammatories as putative anti-brain aging therapies to counteract pathological aging in neurodegenerative diseases.
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Affiliation(s)
- Azhaar Ashraf
- Institute of Psychiatry, Psychology and Neuroscience, Department of Neuroimaging, King's College London, London, United Kingdom
| | - Maryam Clark
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Po-Wah So
- Institute of Psychiatry, Psychology and Neuroscience, Department of Neuroimaging, King's College London, London, United Kingdom
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Baksi S, Singh N. α-Synuclein impairs ferritinophagy in the retinal pigment epithelium: Implications for retinal iron dyshomeostasis in Parkinson's disease. Sci Rep 2017; 7:12843. [PMID: 28993630 PMCID: PMC5634503 DOI: 10.1038/s41598-017-12862-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 09/14/2017] [Indexed: 01/14/2023] Open
Abstract
Retinal degeneration is prominent in Parkinson’s disease (PD), a neuromotor disorder associated with aggregation of α-synuclein (α-syn) in the substantia-nigra (SN). Although α-syn is expressed in the neuroretina, absence of prominent aggregates suggests altered function as the likely cause of retinal pathology. We demonstrate that α-syn impairs ferritinophagy, resulting in the accumulation of iron-rich ferritin in the outer retina in-vivo and retinal-pigment-epithelial (RPE) cells in-vitro. Over-expression of Rab1a restores ferritinophagy, suggesting that α-syn impairs lysosomal function by disrupting the trafficking of lysosomal hydrolases. Surprisingly, upregulation of ferritin in RPE cells by exogenous iron in-vitro stimulated the release of ferritin and α-syn in exosomes, suggesting that iron overload due to impaired ferritinophagy or other cause(s) is likely to initiate prion-like spread of α-syn and ferritin, creating retinal iron dyshomeostasis and associated cytotoxicity. Since over-expression of α-syn is a known cause of PD, these results explain the likely cause of PD-associated retinal degeneration.
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Affiliation(s)
- Shounak Baksi
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, 44106, USA
| | - Neena Singh
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, 44106, USA.
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20
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Asthana A, Baksi S, Ashok A, Karmakar S, Mammadova N, Kokemuller R, Greenlee MH, Kong Q, Singh N. Prion protein facilitates retinal iron uptake and is cleaved at the β-site: Implications for retinal iron homeostasis in prion disorders. Sci Rep 2017; 7:9600. [PMID: 28851903 PMCID: PMC5575325 DOI: 10.1038/s41598-017-08821-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 07/17/2017] [Indexed: 12/22/2022] Open
Abstract
Prion disease-associated retinal degeneration is attributed to PrP-scrapie (PrPSc), a misfolded isoform of prion protein (PrPC) that accumulates in the neuroretina. However, a lack of temporal and spatial correlation between PrPSc and cytotoxicity suggests the contribution of host factors. We report retinal iron dyshomeostasis as one such factor. PrPC is expressed on the basolateral membrane of retinal-pigment-epithelial (RPE) cells, where it mediates uptake of iron by the neuroretina. Accordingly, the neuroretina of PrP-knock-out mice is iron-deficient. In RPE19 cells, silencing of PrPC decreases ferritin while over-expression upregulates ferritin and divalent-metal-transporter-1 (DMT-1), indicating PrPC-mediated iron uptake through DMT-1. Polarization of RPE19 cells results in upregulation of ferritin by ~10-fold and β-cleavage of PrPC, the latter likely to block further uptake of iron due to cleavage of the ferrireductase domain. A similar β-cleavage of PrPC is observed in mouse retinal lysates. Scrapie infection causes PrPSc accumulation and microglial activation, and surprisingly, upregulation of transferrin despite increased levels of ferritin. Notably, detergent-insoluble ferritin accumulates in RPE cells and correlates temporally with microglial activation, not PrPSc accumulation, suggesting that impaired uptake of iron by PrPSc combined with inflammation results in retinal iron-dyshomeostasis, a potentially toxic host response contributing to prion disease-associated pathology.
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Affiliation(s)
- Abhishek Asthana
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, 44106, USA
| | - Shounak Baksi
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, 44106, USA
| | - Ajay Ashok
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, 44106, USA
| | - Shilpita Karmakar
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, 44106, USA
| | - Najiba Mammadova
- Department of Biomedical Sciences, Iowa State University College of Veterinary Medicine, Ames, Iowa, 50010, USA
| | - Robyn Kokemuller
- Department of Biomedical Sciences, Iowa State University College of Veterinary Medicine, Ames, Iowa, 50010, USA
| | - Mary Heather Greenlee
- Department of Biomedical Sciences, Iowa State University College of Veterinary Medicine, Ames, Iowa, 50010, USA
| | - Qingzhong Kong
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, 44106, USA
| | - Neena Singh
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, 44106, USA.
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Crielaard BJ, Lammers T, Rivella S. Targeting iron metabolism in drug discovery and delivery. Nat Rev Drug Discov 2017; 16:400-423. [PMID: 28154410 PMCID: PMC5455971 DOI: 10.1038/nrd.2016.248] [Citation(s) in RCA: 225] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Iron fulfils a central role in many essential biochemical processes in human physiology; thus, proper processing of iron is crucial. Although iron metabolism is subject to relatively strict physiological control, numerous disorders, such as cancer and neurodegenerative diseases, have recently been linked to deregulated iron homeostasis. Consequently, iron metabolism constitutes a promising and largely unexploited therapeutic target for the development of new pharmacological treatments for these diseases. Several iron metabolism-targeted therapies are already under clinical evaluation for haematological disorders, and these and newly developed therapeutic agents are likely to have substantial benefit in the clinical management of iron metabolism-associated diseases, for which few efficacious treatments are currently available.
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Affiliation(s)
- Bart J. Crielaard
- Department of Polymer Chemistry and Bioengineering, Zernike Institute for Advanced Materials, Faculty of Mathematics and Natural Sciences, University of Groningen, Groningen, The Netherlands
- W.J. Kolff Institute for Biomedical Engineering and Materials Science, University Medical Center Groningen, Groningen, The Netherlands
| | - Twan Lammers
- Department of Nanomedicine and Theranostics, Institute for Experimental Molecular Imaging, University Clinic and Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
- Department of Targeted Therapeutics, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Stefano Rivella
- Children’s Hospital of Philadelphia, Abramson Research Center, Philadelphia, PA, United States of America
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22
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Cheng CJ, Koldsø H, Van der Kamp MW, Schiøtt B, Daggett V. Simulations of membrane-bound diglycosylated human prion protein reveal potential protective mechanisms against misfolding. J Neurochem 2017; 142:171-182. [PMID: 28407243 DOI: 10.1111/jnc.14044] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/28/2017] [Accepted: 03/28/2017] [Indexed: 01/06/2023]
Abstract
Prion diseases are associated with the misfolding of the prion protein (PrP) from its normal cellular form (PrPC ) to its infectious scrapie form (PrPSc ). Post-translational modifications in PrP in vivo can play an important role in modulating the process of misfolding. To gain more insight into the effects of post-translational modifications in PrP structure and dynamics and to test the hypothesis that such modifications can interact with the protein, we have performed molecular dynamics simulations of diglycosylated human PrPC bound to a lipid bilayer via a glycophosphatidylinositol anchor. Multiple simulations were performed at three different pH ranges to explore pH effects on structure and dynamics. In contrast to simulations of protein-only PrPC , no large effects were observed upon lowering the pH of the system. The protein tilted toward the membrane surface in all of the simulations and the putative PrPSc oligomerization sites became inaccessible, thereby offering a possible protective mechanism against PrPSc -induced misfolding of PrPC .
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Affiliation(s)
- Chin Jung Cheng
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Heidi Koldsø
- Department of Bioengineering, University of Washington, Seattle, Washington, USA.,Department of Chemistry, inSPIN and iNANO Centers, Aarhus University, Aarhus C, Denmark
| | - Marc W Van der Kamp
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Birgit Schiøtt
- Department of Chemistry, inSPIN and iNANO Centers, Aarhus University, Aarhus C, Denmark
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
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23
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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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24
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Tripathi AK, Singh N. Prion Protein-Hemin Interaction Upregulates Hemoglobin Synthesis: Implications for Cerebral Hemorrhage and Sporadic Creutzfeldt-Jakob Disease. J Alzheimers Dis 2016; 51:107-21. [PMID: 26836195 DOI: 10.3233/jad-151039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Hemin is known to induce endocytosis of prion-protein (PrP(C)) from the neuronal plasma membrane, potentially limiting propagation of the disease causing PrP-scrapie (PrP(Sc)) isoform. Hemin is therefore an attractive disease-modifying option for sporadic Creutzfeldt-Jakob disease (sCJD), a human prion disorder with no effective treatment. The hemin-PrP(C) interaction is also of interest in cerebral-hemorrhage (CH), a condition where potentially toxic hemin molecules come in contact with neuronal PrP(C). Interestingly, PrP(C) is upregulated in penumbric neurons surrounding CH and is known to confer neuroprotection in a dose-dependent manner. The underlying mechanism, however, is not clear. Here, we report that hemin binds PrP(C) on diverse cell lines, resulting in its aggregation or degradation in a cell-type specific manner. Surprisingly, the hemin-PrP(C) interaction upregulates Hb synthesis in hematopoietic cells, a response reversed by deleting the hemin-binding octa-peptide repeat region of PrP(C). A similar response is noted in brain organotypic cultures where exposure to hemin induces significantly more α-globin in wild-type (PrP(+/+)) relative to PrP-knock-out (PrP(-/-)) samples. Furthermore, red blood cells and brain tissue from PrP(-/-) mice show significantly less α-globin relative to PrP(+/+) controls, indicating a positive effect of PrP(C) on Hb synthesis under physiological conditions as well. Surprisingly, levels of α-globin are significantly higher in sCJD brain tissue relative to controls, suggesting compensatory upregulation of Hb synthesis by surviving neurons or misregulation in diseased brains. These observations reveal a unique function of PrP(C) that is likely to impact the therapeutic management of CH and sCJD.
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25
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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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26
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Gasperini L, Meneghetti E, Legname G, Benetti F. In Absence of the Cellular Prion Protein, Alterations in Copper Metabolism and Copper-Dependent Oxidase Activity Affect Iron Distribution. Front Neurosci 2016; 10:437. [PMID: 27729845 PMCID: PMC5037227 DOI: 10.3389/fnins.2016.00437] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 09/09/2016] [Indexed: 12/21/2022] Open
Abstract
Essential elements as copper and iron modulate a wide range of physiological functions. Their metabolism is strictly regulated by cellular pathways, since dysregulation of metal homeostasis is responsible for many detrimental effects. Neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease and prion diseases are characterized by alterations of metal ions. These neurodegenerative maladies involve proteins that bind metals and mediate their metabolism through not well-defined mechanisms. Prion protein, for instance, interacts with divalent cations via multiple metal-binding sites and it modulates several metal-dependent physiological functions, such as S-nitrosylation of NMDA receptors. In this work we focused on the effect of prion protein absence on copper and iron metabolism during development and adulthood. In particular, we investigated copper and iron functional values in serum and several organs such as liver, spleen, total brain and isolated hippocampus. Our results show that iron content is diminished in prion protein-null mouse serum, while it accumulates in liver and spleen. Our data suggest that these alterations can be due to impairments in copper-dependent cerulopalsmin activity which is known to affect iron mobilization. In prion protein-null mouse total brain and hippocampus, metal ion content shows a fluctuating trend, suggesting the presence of homeostatic compensatory mechanisms. However, copper and iron functional values are likely altered also in these two organs, as indicated by the modulation of metal-binding protein expression levels. Altogether, these results reveal that the absence of the cellular prion protein impairs copper metabolism and copper-dependent oxidase activity, with ensuing alteration of iron mobilization from cellular storage compartments.
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Affiliation(s)
- Lisa Gasperini
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati Trieste, Italy
| | - Elisa Meneghetti
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati Trieste, Italy
| | - Giuseppe Legname
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati Trieste, Italy
| | - Federico Benetti
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati Trieste, Italy
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27
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Singh N, Asthana A, Baksi S, Desai V, Haldar S, Hari S, Tripathi AK. The prion-ZIP connection: From cousins to partners in iron uptake. Prion 2016; 9:420-8. [PMID: 26689487 PMCID: PMC4964862 DOI: 10.1080/19336896.2015.1118602] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Converging observations from disparate lines of inquiry are beginning to clarify the cause of brain iron dyshomeostasis in sporadic Creutzfeldt-Jakob disease (sCJD), a neurodegenerative condition associated with the conversion of prion protein (PrPC), a plasma membrane glycoprotein, from α-helical to a β-sheet rich PrP-scrapie (PrPSc) isoform. Biochemical evidence indicates that PrPC facilitates cellular iron uptake by functioning as a membrane-bound ferrireductase (FR), an activity necessary for the transport of iron across biological membranes through metal transporters. An entirely different experimental approach reveals an evolutionary link between PrPC and the Zrt, Irt-like protein (ZIP) family, a group of proteins involved in the transport of zinc, iron, and manganese across the plasma membrane. Close physical proximity of PrPC with certain members of the ZIP family on the plasma membrane and increased uptake of extracellular iron by cells that co-express PrPC and ZIP14 suggest that PrPC functions as a FR partner for certain members of this family. The connection between PrPC and ZIP proteins therefore extends beyond common ancestry to that of functional cooperation. Here, we summarize evidence supporting the facilitative role of PrPC in cellular iron uptake, and implications of this activity on iron metabolism in sCJD brains.
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Affiliation(s)
- Neena Singh
- a Department of Pathology ; School of Medicine; Case Western Reserve University ; Cleveland , OH USA
| | - Abhishek Asthana
- a Department of Pathology ; School of Medicine; Case Western Reserve University ; Cleveland , OH USA
| | - Shounak Baksi
- a Department of Pathology ; School of Medicine; Case Western Reserve University ; Cleveland , OH USA
| | - Vilok Desai
- a Department of Pathology ; School of Medicine; Case Western Reserve University ; Cleveland , OH USA
| | - Swati Haldar
- a Department of Pathology ; School of Medicine; Case Western Reserve University ; Cleveland , OH USA
| | - Sahi Hari
- a Department of Pathology ; School of Medicine; Case Western Reserve University ; Cleveland , OH USA
| | - Ajai K Tripathi
- a Department of Pathology ; School of Medicine; Case Western Reserve University ; Cleveland , OH USA
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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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Murphy S, Zweyer M, Henry M, Meleady P, Mundegar RR, Swandulla D, Ohlendieck K. Label-free mass spectrometric analysis reveals complex changes in the brain proteome from the mdx-4cv mouse model of Duchenne muscular dystrophy. Clin Proteomics 2015; 12:27. [PMID: 26604869 PMCID: PMC4657206 DOI: 10.1186/s12014-015-9099-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 11/13/2015] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND X-linked muscular dystrophy is a primary disease of the neuromuscular system. Primary abnormalities in the Dmd gene result in the absence of the full-length isoform of the membrane cytoskeletal protein dystrophin. Besides progressive skeletal muscle wasting and cardio-respiratory complications, developmental cognitive deficits and behavioural abnormalities are clinical features of Duchenne muscular dystrophy. In order to better understand the mechanisms that underlie impaired brain functions in Duchenne patients, we have carried out a proteomic analysis of total brain extracts from the mdx-4cv mouse model of dystrophinopathy. RESULTS The comparative proteomic profiling of the mdx-4cv brain revealed a significant increase in 39 proteins and a decrease in 7 proteins. Interesting brain tissue-associated proteins with an increased concentration in the mdx-4cv animal model were represented by the glial fibrillary acidic protein GFAP, the neuronal Ca(2+)-binding protein calretinin, annexin AnxA5, vimentin, the neuron-specific enzyme ubiquitin carboxyl-terminal hydrolase isozyme L1, the dendritic spine protein drebrin, the cytomatrix protein bassoon of the nerve terminal active zone, and the synapse-associated protein SAP97. Decreased proteins were identified as the nervous system-specific proteins syntaxin-1B and syntaxin-binding protein 1, as well as the plasma membrane Ca(2+)-transporting ATPase PMCA2 that is mostly found in the brain cortex. The differential expression patterns of GFAP, vimentin, PMCA2 and AnxA5 were confirmed by immunoblotting. Increased GFAP levels were also verified by immunofluorescence microscopy. CONCLUSIONS The large number of mass spectrometrically identified proteins with an altered abundance suggests complex changes in the mdx-4cv brain proteome. Increased levels of the glial fibrillary acidic protein, an intermediate filament component that is uniquely associated with astrocytes in the central nervous system, imply neurodegeneration-associated astrogliosis. The up-regulation of annexin and vimentin probably represent compensatory mechanisms involved in membrane repair and cytoskeletal stabilization in the absence of brain dystrophin. Differential alterations in the Ca(2+)-binding protein calretinin and the Ca(2+)-pumping protein PMCA2 suggest altered Ca(2+)-handling mechanisms in the Dp427-deficient brain. In addition, the proteomic findings demonstrated metabolic adaptations and functional changes in the central nervous system from the dystrophic phenotype. Candidate proteins can now be evaluated for their suitability as proteomic biomarkers and their potential in predictive, diagnostic, prognostic and/or therapy-monitoring approaches to treat brain abnormalities in dystrophinopathies.
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Affiliation(s)
- Sandra Murphy
- Department of Biology, Maynooth University, National University of Ireland, Maynooth, Co. Kildare Ireland
| | - Margit Zweyer
- Department of Physiology II, University of Bonn, 53115 Bonn, Germany
| | - Michael Henry
- National Institute for Cellular Biotechnology, Dublin City University, Dublin 9, Ireland
| | - Paula Meleady
- National Institute for Cellular Biotechnology, Dublin City University, Dublin 9, Ireland
| | - Rustam R Mundegar
- Department of Physiology II, University of Bonn, 53115 Bonn, Germany
| | - Dieter Swandulla
- Department of Physiology II, University of Bonn, 53115 Bonn, Germany
| | - Kay Ohlendieck
- Department of Biology, Maynooth University, National University of Ireland, Maynooth, Co. Kildare Ireland
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Peters DG, Connor JR, Meadowcroft MD. The relationship between iron dyshomeostasis and amyloidogenesis in Alzheimer's disease: Two sides of the same coin. Neurobiol Dis 2015; 81:49-65. [PMID: 26303889 DOI: 10.1016/j.nbd.2015.08.007] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 08/04/2015] [Accepted: 08/12/2015] [Indexed: 12/21/2022] Open
Abstract
The dysregulation of iron metabolism in Alzheimer's disease is not accounted for in the current framework of the amyloid cascade hypothesis. Accumulating evidence suggests that impaired iron homeostasis is an early event in Alzheimer's disease progression. Iron dyshomeostasis leads to a loss of function in several enzymes requiring iron as a cofactor, the formation of toxic oxidative species, and the elevated production of beta-amyloid proteins. Several common genetic polymorphisms that cause increased iron levels and dyshomeostasis have been associated with Alzheimer's disease but the pathoetiology is not well understood. A full picture is necessary to explain how heterogeneous circumstances lead to iron loading and amyloid deposition. There is evidence to support a causative interplay between the concerted loss of iron homeostasis and amyloid plaque formation. We hypothesize that iron misregulation and beta-amyloid plaque pathology are synergistic in the process of neurodegeneration and ultimately cause a downward cascade of events that spiral into the manifestation of Alzheimer's disease. In this review, we amalgamate recent findings of brain iron metabolism in healthy versus Alzheimer's disease brains and consider unique mechanisms of iron transport in different brain cells as well as how disturbances in iron regulation lead to disease etiology and propagate Alzheimer's pathology.
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Affiliation(s)
- Douglas G Peters
- Department of Neurosurgery, The Pennsylvania State University, College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA; Department of Neural and Behavioral Sciences, The Pennsylvania State University, College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA
| | - James R Connor
- Department of Neurosurgery, The Pennsylvania State University, College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA
| | - Mark D Meadowcroft
- Department of Neurosurgery, The Pennsylvania State University, College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA; Department of Radiology, The Center for NMR Research, The Pennsylvania State University, College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA.
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Appraising the Role of Iron in Brain Aging and Cognition: Promises and Limitations of MRI Methods. Neuropsychol Rev 2015; 25:272-87. [PMID: 26248580 DOI: 10.1007/s11065-015-9292-y] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 07/24/2015] [Indexed: 12/11/2022]
Abstract
Age-related increase in frailty is accompanied by a fundamental shift in cellular iron homeostasis. By promoting oxidative stress, the intracellular accumulation of non-heme iron outside of binding complexes contributes to chronic inflammation and interferes with normal brain metabolism. In the absence of direct non-invasive biomarkers of brain oxidative stress, iron accumulation estimated in vivo may serve as its proxy indicator. Hence, developing reliable in vivo measurements of brain iron content via magnetic resonance imaging (MRI) is of significant interest in human neuroscience. To date, by estimating brain iron content through various MRI methods, significant age differences and age-related increases in iron content of the basal ganglia have been revealed across multiple samples. Less consistent are the findings that pertain to the relationship between elevated brain iron content and systemic indices of vascular and metabolic dysfunction. Only a handful of cross-sectional investigations have linked high iron content in various brain regions and poor performance on assorted cognitive tests. The even fewer longitudinal studies indicate that iron accumulation may precede shrinkage of the basal ganglia and thus predict poor maintenance of cognitive functions. This rapidly developing field will benefit from introduction of higher-field MRI scanners, improvement in iron-sensitive and -specific acquisition sequences and post-processing analytic and computational methods, as well as accumulation of data from long-term longitudinal investigations. This review describes the potential advantages and promises of MRI-based assessment of brain iron, summarizes recent findings and highlights the limitations of the current methodology.
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Tripathi AK, Haldar S, Qian J, Beserra A, Suda S, Singh A, Hopfer U, Chen SG, Garrick MD, Turner JR, Knutson MD, Singh N. Prion protein functions as a ferrireductase partner for ZIP14 and DMT1. Free Radic Biol Med 2015; 84:322-330. [PMID: 25862412 PMCID: PMC4476631 DOI: 10.1016/j.freeradbiomed.2015.03.037] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 03/30/2015] [Accepted: 03/30/2015] [Indexed: 12/21/2022]
Abstract
Excess circulating iron is stored in the liver, and requires reduction of non-Tf-bound iron (NTBI) and transferrin (Tf) iron at the plasma membrane and endosomes, respectively, by ferrireductase (FR) proteins for transport across biological membranes through divalent metal transporters. Here, we report that prion protein (PrP(C)), a ubiquitously expressed glycoprotein most abundant on neuronal cells, functions as a FR partner for divalent-metal transporter-1 (DMT1) and ZIP14. Thus, absence of PrP(C) in PrP-knock-out (PrP(-/-)) mice resulted in markedly reduced liver iron stores, a deficiency that was not corrected by chronic or acute administration of iron by the oral or intraperitoneal routes. Likewise, preferential radiolabeling of circulating NTBI with (59)Fe revealed significantly reduced uptake and storage of NTBI by the liver of PrP(-/-) mice relative to matched PrP(+/+) controls. However, uptake, storage, and utilization of ferritin-bound iron that does not require reduction for uptake were increased in PrP(-/-) mice, indicating a compensatory response to the iron deficiency. Expression of exogenous PrP(C) in HepG2 cells increased uptake and storage of ferric iron (Fe(3+)), not ferrous iron (Fe(2+)), from the medium, supporting the function of PrP(C) as a plasma membrane FR. Coexpression of PrP(C) with ZIP14 and DMT1 in HepG2 cells increased uptake of Fe(3+) significantly, and surprisingly, increased the ratio of N-terminally truncated PrP(C) forms lacking the FR domain relative to full-length PrP(C). Together, these observations indicate that PrP(C) promotes, and possibly regulates, the uptake of NTBI through DMT1 and Zip14 via its FR activity. Implications of these observations for neuronal iron homeostasis under physiological and pathological conditions are discussed.
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Affiliation(s)
- Ajai K. Tripathi
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Swati Haldar
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Juan Qian
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Amber Beserra
- School of Arts and Sciences, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Srinivas Suda
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Ajay Singh
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Ulrich Hopfer
- Department of physiology and Biophysics, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Shu G. Chen
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | | | | | | | - Neena Singh
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
- To whom correspondence should be addressed: Neena Singh, Department of Pathology, Case Western Reserve University, 2103 Cornell Road, Cleveland, Ohio 44106, USA. Tel: 216-368-2617;
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Rassu G, Soddu E, Cossu M, Brundu A, Cerri G, Marchetti N, Ferraro L, Regan RF, Giunchedi P, Gavini E, Dalpiaz A. Solid microparticles based on chitosan or methyl-β-cyclodextrin: a first formulative approach to increase the nose-to-brain transport of deferoxamine mesylate. J Control Release 2015; 201:68-77. [PMID: 25620068 PMCID: PMC4330128 DOI: 10.1016/j.jconrel.2015.01.025] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 01/20/2015] [Accepted: 01/21/2015] [Indexed: 12/12/2022]
Abstract
We propose the formulation and characterization of solid microparticles as nasal drug delivery systems able to increase the nose-to-brain transport of deferoxamine mesylate (DFO), a neuroprotector unable to cross the blood brain barrier and inducing negative peripheral impacts. Spherical chitosan chloride and methyl-β-cyclodextrin microparticles loaded with DFO (DCH and MCD, respectively) were obtained by spray drying. Their volume-surface diameters ranged from 1.77 ± 0.06 μm (DCH) to 3.47 ± 0.05 μm (MCD); the aerodynamic diameters were about 1.1 μm and their drug content was about 30%. In comparison with DCH, MCD enhanced the in vitro DFO permeation across lipophilic membranes, similarly as shown by ex vivo permeation studies across porcine nasal mucosa. Moreover, MCD were able to promote the DFO permeation across monolayers of PC 12 cells (neuron-like), but like DCH, it did not modify the DFO permeation pattern across Caco-2 monolayers (epithelial-like). Nasal administration to rats of 200 μg DFO encapsulated in the microparticles resulted in its uptake into the cerebrospinal fluid (CSF) with peak values ranging from 3.83 ± 0.68 μg/mL (DCH) to 14.37 ± 1.69 μg/mL (MCD) 30 min after insufflation of microparticles. No drug CSF uptake was detected after nasal administration of a DFO water solution. The DFO systemic absolute bioavailabilities obtained by DCH and MCD nasal administration were 6% and 15%, respectively. Chitosan chloride and methyl-β-cyclodextrins appear therefore suitable to formulate solid microparticles able to promote the nose to brain uptake of DFO and to limit its systemic exposure.
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Affiliation(s)
- Giovanna Rassu
- Department of Chemistry and Pharmacy, University of Sassari, via Muroni 23/a, 07100 Sassari, Italy
| | - Elena Soddu
- Department of Chemistry and Pharmacy, University of Sassari, via Muroni 23/a, 07100 Sassari, Italy
| | - Massimo Cossu
- Department of Chemistry and Pharmacy, University of Sassari, via Muroni 23/a, 07100 Sassari, Italy
| | - Antonio Brundu
- Department of Natural and Territorial Sciences, University of Sassari, via Piandanna 4, 07100 Sassari, Italy
| | - Guido Cerri
- Department of Natural and Territorial Sciences, University of Sassari, via Piandanna 4, 07100 Sassari, Italy
| | - Nicola Marchetti
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, via Fossato di Mortara 19, 44121 Ferrara, Italy
| | - Luca Ferraro
- Department of Life Sciences and Biotechnology, University of Ferrara, via Borsari 46, 44121 Ferrara, Italy
| | - Raymond F Regan
- Department of Emergency Medicine, Thomas Jefferson University, Philadelphia, USA
| | - Paolo Giunchedi
- Department of Chemistry and Pharmacy, University of Sassari, via Muroni 23/a, 07100 Sassari, Italy
| | - Elisabetta Gavini
- Department of Chemistry and Pharmacy, University of Sassari, via Muroni 23/a, 07100 Sassari, Italy.
| | - Alessandro Dalpiaz
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, via Fossato di Mortara 19, 44121 Ferrara, Italy
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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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Affiliation(s)
- Neena Singh
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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Li Y, Guan Q, Chen Y, Han H, Liu W, Nie Z. Transferrin receptor and ferritin-H are developmentally regulated in oligodendrocyte lineage cells. Neural Regen Res 2014; 8:6-12. [PMID: 25206366 PMCID: PMC4107500 DOI: 10.3969/j.issn.1673-5374.2013.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 10/17/2012] [Indexed: 12/11/2022] Open
Abstract
Iron is an essential trophic element that is required for cell viability and differentiation, especially in oligodendrocytes, which consume relatively high rates of energy to produce myelin. Multiple iron metabolism proteins are expressed in the brain including transferrin receptor and ferritin-H. However, it is still unknown whether they are developmentally regulated in oligodendrocyte lineage cells for myelination. Here, using an in vitro cultured differentiation model of oligodendrocytes, we found that both transferrin receptor and ferritin-H are significantly upregulated during oligodendrocyte maturation, implying the essential role of iron in the development of oligodendrocytes. Additional different doses of Fe3+ in the cultured medium did not affect oligodendrocyte precursor cell maturation or ferritin-H expression but decreased the expression of the transferrin receptor. These results indicate that upregulation of both transferrin receptor and ferritin-H contributes to maturation and myelination of oligodendrocyte precursor cells.
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Affiliation(s)
- Yunxia Li
- Department of Neurology, Shanghai Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Qiang Guan
- Department of Neurology, Shanghai Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Yuhui Chen
- Department of Neurology, Shanghai Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Hongjie Han
- Department of Neurology, Shanghai Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Wuchao Liu
- Department of Neurology, Shanghai Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Zhiyu Nie
- Department of Neurology, Shanghai Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
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Biology of ferritin in mammals: an update on iron storage, oxidative damage and neurodegeneration. Arch Toxicol 2014; 88:1787-802. [PMID: 25119494 DOI: 10.1007/s00204-014-1329-0] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 08/04/2014] [Indexed: 12/12/2022]
Abstract
Iron is an abundant transition metal that is essential for life, being associated with many enzyme and oxygen carrier proteins involved in a variety of fundamental cellular processes. At the same time, the metal is potentially toxic due to its capacity to engage in the catalytic production of noxious reactive oxygen species. The control of iron availability in the cells is largely dependent on ferritins, ubiquitous proteins with storage and detoxification capacity. In mammals, cytosolic ferritins are composed of two types of subunits, the H and the L chain, assembled to form a 24-mer spherical cage. Ferritin is present also in mitochondria, in the form of a complex with 24 identical chains. Even though the proteins have been known for a long time, their study is a very active and interesting field yet. In this review, we will focus our attention to mammalian cytosolic and mitochondrial ferritins, describing the most recent advancement regarding their storage and antioxidant function, the effects of their genetic mutations in human pathology, and also the possible involvement in non-iron-related activities. We will also discuss recent evidence connecting ferritins and the toxicity of iron in a set of neurodegenerative disorder characterized by focal cerebral siderosis.
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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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Wong BX, Duce JA. The iron regulatory capability of the major protein participants in prevalent neurodegenerative disorders. Front Pharmacol 2014; 5:81. [PMID: 24795635 PMCID: PMC4001010 DOI: 10.3389/fphar.2014.00081] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/02/2014] [Indexed: 12/23/2022] Open
Abstract
As with most bioavailable transition metals, iron is essential for many metabolic processes required by the cell but when left unregulated is implicated as a potent source of reactive oxygen species. It is uncertain whether the brain’s evident vulnerability to reactive species-induced oxidative stress is caused by a reduced capability in cellular response or an increased metabolic activity. Either way, dys-regulated iron levels appear to be involved in oxidative stress provoked neurodegeneration. As in peripheral iron management, cells within the central nervous system tightly regulate iron homeostasis via responsive expression of select proteins required for iron flux, transport and storage. Recently proteins directly implicated in the most prevalent neurodegenerative diseases, such as amyloid-β precursor protein, tau, α-synuclein, prion protein and huntingtin, have been connected to neuronal iron homeostatic control. This suggests that disrupted expression, processing, or location of these proteins may result in a failure of their cellular iron homeostatic roles and augment the common underlying susceptibility to neuronal oxidative damage that is triggered in neurodegenerative disease.
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Affiliation(s)
- Bruce X Wong
- Oxidation Biology Unit, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne Parkville, VIC, Australia
| | - James A Duce
- Oxidation Biology Unit, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne Parkville, VIC, Australia ; School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds Leeds, UK
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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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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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Haldar S, Beveridge ’AJ, Wong J, Singh A, Galimberti D, Borroni B, Zhu X, Blevins J, Greenlee J, Perry G, Mukhopadhyay CK, Schmotzer C, Singh N. A low-molecular-weight ferroxidase is increased in the CSF of sCJD cases: CSF ferroxidase and transferrin as diagnostic biomarkers for sCJD. Antioxid Redox Signal 2013; 19:1662-75. [PMID: 23379482 PMCID: PMC3809602 DOI: 10.1089/ars.2012.5032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 02/01/2013] [Accepted: 02/04/2013] [Indexed: 12/19/2022]
Abstract
AIMS Most biomarkers used for the premortem diagnosis of sporadic Creutzfeldt-Jakob disease (CJD) are surrogate in nature, and provide suboptimal sensitivity and specificity. RESULTS We report that CJD-associated brain iron dyshomeostasis is reflected in the cerebrospinal fluid (CSF), providing disease-specific diagnostic biomarkers. Analysis of 290 premortem CSF samples from confirmed cases of CJD, Alzheimer's disease, and other dementias (DMs), and 52 non-DM (ND) controls revealed a significant difference in ferroxidase (Frx) activity and transferrin (Tf) levels in sporadic Creutzfeldt-Jakob disease (sCJD) relative to other DM and ND controls. A combination of CSF Frx and Tf discriminated sCJD from other DMs with a sensitivity of 86.8%, specificity of 92.5%, accuracy of 88.9%, and area-under-the receiver-operating-characteristic (ROC) curve of 0.94. This combination provided a similar diagnostic accuracy in discriminating CJD from rapidly progressing cases who died within 6 months of sample collection. Surprisingly, ceruloplasmin and amyloid precursor protein, the major brain Frxs, displayed minimal activity in the CSF. Most of the Frx activity was concentrated in the <3-kDa fraction in normal and diseased CSF, and resisted heat and proteinase-K treatment. INNOVATION (i) A combination of CSF Frx and Tf provides disease-specific premortem diagnostic biomarkers for sCJD. (ii) A novel, nonenzymatic, nonprotein Frx predominates in human CSF that is distinct from the currently known CSF Frxs. CONCLUSION The underlying cause of iron imbalance is distinct in sCJD relative to other DMs associated with the brain iron imbalance. Thus, change in the CSF levels of iron-management proteins can provide disease-specific biomarkers and insight into the cause of iron imbalance in neurodegenerative conditions.
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Affiliation(s)
- Swati Haldar
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio
| | - ’Alim J. Beveridge
- Department of Organizational Behavior, Case Western Reserve University, Cleveland, Ohio
| | - Joseph Wong
- Case Medical School, Case Western Reserve University, Cleveland, Ohio
| | - Ajay Singh
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio
| | - Daniela Galimberti
- Department of Pathophysiology and Transplantation, Centro Dino Ferrari, Fondazione Cà Granda, IRCCS Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Barbara Borroni
- Neurology Unit, Centre for Neurodegenerative Disorders, University of Brescia, Brescia, Italy
| | - Xiongwei Zhu
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio
| | - Janis Blevins
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio
| | - Justin Greenlee
- Virus and Prion Research Unit, National Animal Disease Center, ARS, USDA, Ames, Iowa
| | - George Perry
- College of Sciences, The University of Texas at San Antonio, San Antonio, Texas
| | | | | | - Neena Singh
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio
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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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Chen J, Marks E, Lai B, Zhang Z, Duce JA, Lam LQ, Volitakis I, Bush AI, Hersch S, Fox JH. Iron accumulates in Huntington's disease neurons: protection by deferoxamine. PLoS One 2013; 8:e77023. [PMID: 24146952 PMCID: PMC3795666 DOI: 10.1371/journal.pone.0077023] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 08/26/2013] [Indexed: 01/13/2023] Open
Abstract
Huntington’s disease (HD) is a progressive neurodegenerative disorder caused by a polyglutamine-encoding CAG expansion in the huntingtin gene. Iron accumulates in the brains of HD patients and mouse disease models. However, the cellular and subcellular sites of iron accumulation, as well as significance to disease progression are not well understood. We used independent approaches to investigate the location of brain iron accumulation. In R6/2 HD mouse brain, synchotron x-ray fluorescence analysis revealed iron accumulation as discrete puncta in the perinuclear cytoplasm of striatal neurons. Further, perfusion Turnbull’s staining for ferrous iron (II) combined with transmission electron microscope ultra-structural analysis revealed increased staining in membrane bound peri-nuclear vesicles in R6/2 HD striatal neurons. Analysis of iron homeostatic proteins in R6/2 HD mice revealed decreased levels of the iron response proteins (IRPs 1 and 2) and accordingly decreased expression of iron uptake transferrin receptor (TfR) and increased levels of neuronal iron export protein ferroportin (FPN). Finally, we show that intra-ventricular delivery of the iron chelator deferoxamine results in an improvement of the motor phenotype in R6/2 HD mice. Our data supports accumulation of redox-active ferrous iron in the endocytic / lysosomal compartment in mouse HD neurons. Expression changes of IRPs, TfR and FPN are consistent with a compensatory response to an increased intra-neuronal labile iron pool leading to increased susceptibility to iron-associated oxidative stress. These findings, together with protection by deferoxamine, support a potentiating role of neuronal iron accumulation in HD.
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Affiliation(s)
- Jianfang Chen
- Department of Veterinary Sciences and Neuroscience Graduate Program, University of Wyoming, Laramie, Wyoming, United States of America
| | - Eileen Marks
- Department of Veterinary Sciences and Neuroscience Graduate Program, University of Wyoming, Laramie, Wyoming, United States of America
| | - Barry Lai
- Argonne National Laboratory, Lemont, Illinois, United States of America
| | - Zhaojie Zhang
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, United States of America
| | - James A. Duce
- Mental Health Research Institute, Parkville, Melbourne, Victoria, Australia
- School of Molecular and Cellular Biology, the Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Linh Q. Lam
- Mental Health Research Institute, Parkville, Melbourne, Victoria, Australia
| | - Irene Volitakis
- Mental Health Research Institute, Parkville, Melbourne, Victoria, Australia
| | - Ashley I. Bush
- Mental Health Research Institute, Parkville, Melbourne, Victoria, Australia
| | - Steven Hersch
- MassGeneral Institute for Neurodegenerative Disease, Charlestown, Massachusetts, United States of America
| | - Jonathan H. Fox
- Department of Veterinary Sciences and Neuroscience Graduate Program, University of Wyoming, Laramie, Wyoming, United States of America
- * E-mail:
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Global Protein Differential Expression Profiling of Cerebrospinal Fluid Samples Pooled from Chinese Sporadic CJD and non-CJD Patients. Mol Neurobiol 2013; 49:290-302. [DOI: 10.1007/s12035-013-8519-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Accepted: 07/17/2013] [Indexed: 12/14/2022]
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Bandyopadhyay S, Cahill C, Balleidier A, Huang C, Lahiri DK, Huang X, Rogers JT. Novel 5' untranslated region directed blockers of iron-regulatory protein-1 dependent amyloid precursor protein translation: implications for down syndrome and Alzheimer's disease. PLoS One 2013; 8:e65978. [PMID: 23935819 PMCID: PMC3729844 DOI: 10.1371/journal.pone.0065978] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Accepted: 04/30/2013] [Indexed: 11/19/2022] Open
Abstract
We reported that iron influx drives the translational expression of the neuronal amyloid precursor protein (APP), which has a role in iron efflux. This is via a classic release of repressor interaction of APP mRNA with iron-regulatory protein-1 (IRP1) whereas IRP2 controls the mRNAs encoding the L- and H-subunits of the iron storage protein, ferritin. Here, we identified thirteen potent APP translation blockers that acted selectively towards the uniquely configured iron-responsive element (IRE) RNA stem loop in the 5' untranslated region (UTR) of APP mRNA. These agents were 10-fold less inhibitory of 5'UTR sequences of the related prion protein (PrP) mRNA. Western blotting confirmed that the 'ninth' small molecule in the series selectively reduced neural APP production in SH-SY5Y cells at picomolar concentrations without affecting viability or the expression of α-synuclein and ferritin. APP blocker-9 (JTR-009), a benzimidazole, reduced the production of toxic Aβ in SH-SY5Y neuronal cells to a greater extent than other well tolerated APP 5'UTR-directed translation blockers, including posiphen, that were shown to limit amyloid burden in mouse models of Alzheimer's disease (AD). RNA binding assays demonstrated that JTR-009 operated by preventing IRP1 from binding to the IRE in APP mRNA, while maintaining IRP1 interaction with the H-ferritin IRE RNA stem loop. Thus, JTR-009 constitutively repressed translation driven by APP 5'UTR sequences. Calcein staining showed that JTR-009 did not indirectly change iron uptake in neuronal cells suggesting a direct interaction with the APP 5'UTR. These studies provide key data to develop small molecules that selectively reduce neural APP and Aβ production at 10-fold lower concentrations than related previously characterized translation blockers. Our data evidenced a novel therapeutic strategy of potential impact for people with trisomy of the APP gene on chromosome 21, which is a phenotype long associated with Down syndrome (DS) that can also cause familial Alzheimer's disease.
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Affiliation(s)
- Sanghamitra Bandyopadhyay
- Neurochemistry Laboratory, Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Catherine Cahill
- Neurochemistry Laboratory, Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, United States of America
- Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Amelie Balleidier
- Neurochemistry Laboratory, Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Conan Huang
- Neurochemistry Laboratory, Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Debomoy K. Lahiri
- Laboratory of Molecular Neurogenetics, Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Xudong Huang
- Neurochemistry Laboratory, Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Jack T. Rogers
- Neurochemistry Laboratory, Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, United States of America
- * E-mail:
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Hare D, Ayton S, Bush A, Lei P. A delicate balance: Iron metabolism and diseases of the brain. Front Aging Neurosci 2013; 5:34. [PMID: 23874300 PMCID: PMC3715022 DOI: 10.3389/fnagi.2013.00034] [Citation(s) in RCA: 275] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/25/2013] [Indexed: 12/12/2022] Open
Abstract
Iron is the most abundant transition metal within the brain, and is vital for a number of cellular processes including neurotransmitter synthesis, myelination of neurons, and mitochondrial function. Redox cycling between ferrous and ferric iron is utilized in biology for various electron transfer reactions essential to life, yet this same chemistry mediates deleterious reactions with oxygen that induce oxidative stress. Consequently, there is a precise and tightly controlled mechanism to regulate iron in the brain. When iron is dysregulated, both conditions of iron overload and iron deficiencies are harmful to the brain. This review focuses on how iron metabolism is maintained in the brain, and how an alteration to iron and iron metabolism adversely affects neurological function.
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Affiliation(s)
- Dominic Hare
- The Florey Institute of Neuroscience and Mental Health, University of MelbourneVIC, Australia
- Elemental Bio-imaging Facility, University of TechnologySydney, NSW, Australia
| | - Scott Ayton
- The Florey Institute of Neuroscience and Mental Health, University of MelbourneVIC, Australia
| | - Ashley Bush
- The Florey Institute of Neuroscience and Mental Health, University of MelbourneVIC, Australia
| | - Peng Lei
- The Florey Institute of Neuroscience and Mental Health, University of MelbourneVIC, Australia
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Zhou Z, Xiao G. Conformational conversion of prion protein in prion diseases. Acta Biochim Biophys Sin (Shanghai) 2013; 45:465-76. [PMID: 23580591 DOI: 10.1093/abbs/gmt027] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Prion diseases are a group of infectious fatal neurodegenerative diseases. The conformational conversion of a cellular prion protein (PrP(C)) into an abnormal misfolded isoform (PrP(Sc)) is the key event in prion diseases pathology. Under normal conditions, the high-energy barrier separates PrP(C) from PrP(Sc) isoform. However, pathogenic mutations, modifications as well as some cofactors, such as glycosaminoglycans, nucleic acids, and lipids, could modulate the conformational conversion process. Understanding the mechanism of conformational conversion of prion protein is essential for the biomedical research and the treatment of prion diseases. Particularly, the characterization of cofactors interacting with prion protein might provide new diagnostic and therapeutic strategies.
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Affiliation(s)
- Zheng Zhou
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China
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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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