1
|
Gale J, Aizenman E. The physiological and pathophysiological roles of copper in the nervous system. Eur J Neurosci 2024; 60:3505-3543. [PMID: 38747014 DOI: 10.1111/ejn.16370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 02/28/2024] [Accepted: 04/10/2024] [Indexed: 07/06/2024]
Abstract
Copper is a critical trace element in biological systems due the vast number of essential enzymes that require the metal as a cofactor, including cytochrome c oxidase, superoxide dismutase and dopamine-β-hydroxylase. Due its key role in oxidative metabolism, antioxidant defence and neurotransmitter synthesis, copper is particularly important for neuronal development and proper neuronal function. Moreover, increasing evidence suggests that copper also serves important functions in synaptic and network activity, the regulation of circadian rhythms, and arousal. However, it is important to note that because of copper's ability to redox cycle and generate reactive species, cellular levels of the metal must be tightly regulated to meet cellular needs while avoiding copper-induced oxidative stress. Therefore, it is essential that the intricate system of copper transporters, exporters, copper chaperones and copper trafficking proteins function properly and in coordinate fashion. Indeed, disorders of copper metabolism such as Menkes disease and Wilson disease, as well as diseases linked to dysfunction of copper-requiring enzymes, such as SOD1-linked amyotrophic lateral sclerosis, demonstrate the dramatic neurological consequences of altered copper homeostasis. In this review, we explore the physiological importance of copper in the nervous system as well as pathologies related to improper copper handling.
Collapse
Affiliation(s)
- Jenna Gale
- Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Elias Aizenman
- Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| |
Collapse
|
2
|
Chakraborty K, Kar S, Rai B, Bhagat R, Naskar N, Seth P, Gupta A, Bhattacharjee A. Copper dependent ERK1/2 phosphorylation is essential for the viability of neurons and not glia. Metallomics 2022; 14:mfac005. [PMID: 35150272 PMCID: PMC8975716 DOI: 10.1093/mtomcs/mfac005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 02/10/2022] [Indexed: 01/24/2023]
Abstract
Intracellular copper [Cu(I)] has been hypothesized to play role in the differentiation of the neurons. This necessitates understanding the role of Cu(I) not only in the neurons but also in the glia considering their anatomical proximity, contribution towards ion homeostasis, and neurodegeneration. In this study, we did a systematic investigation of the changes in the cellular copper homeostasis during neuronal and glial differentiation and the pathways triggered by them. Our study demonstrates increased mRNA for the plasma membrane copper transporter CTR1 leading to increased Cu(I) during the neuronal (PC-12) differentiation. ATP7A is retained in the trans-Golgi network (TGN) despite high Cu(I) demonstrating its utilization towards the neuronal differentiation. Intracellular copper triggers pathways essential for neurite generation and ERK1/2 activation during the neuronal differentiation. ERK1/2 activation also accompanies the differentiation of the foetal brain derived neuronal progenitor cells. The study demonstrates that ERK1/2 phosphorylation is essential for the viability of the neurons. In contrast, differentiated C-6 (glia) cells contain low intracellular copper and significant downregulation of the ERK1/2 phosphorylation demonstrating that ERK1/2 activation does not regulate the viability of the glia. But ATP7A shows vesicular localization despite low copper in the glia. In addition to the TGN, ATP7A localizes into RAB11 positive recycling endosomes in the glial neurites. Our study demonstrates the role of copper dependent ERK1/2 phosphorylation in the neuronal viability. Whereas glial differentiation largely involves sequestration of Cu(I) into the endosomes potentially (i) for ready release and (ii) rendering cytosolic copper unavailable for pathways like the ERK1/2 activation.
Collapse
Affiliation(s)
| | - Sumanta Kar
- Department of Biological Sciences, Indian Institute of Science Education and Research, Kolkata, India
| | - Bhawana Rai
- Amity Institute of Biotechnology, Amity University, Kolkata, India
| | - Reshma Bhagat
- Molecular and Cellular Neuroscience, Neurovirology Division, National Brain Research Centre, Manesar, India
| | - Nabanita Naskar
- Chemical Sciences Division, Saha Institute of Nuclear Physics, Kolkata, India
| | - Pankaj Seth
- Molecular and Cellular Neuroscience, Neurovirology Division, National Brain Research Centre, Manesar, India
| | - Arnab Gupta
- Department of Biological Sciences, Indian Institute of Science Education and Research, Kolkata, India
| | | |
Collapse
|
3
|
Chin-Chan M, Montes S, Blanco-Álvarez VM, Aguirre-Alarcón HA, Hernández-Rodríguez I, Bautista E. Relevance of biometals during neuronal differentiation and myelination: in vitro and in vivo studies. Biometals 2022; 35:395-427. [DOI: 10.1007/s10534-022-00380-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 02/27/2022] [Indexed: 12/20/2022]
|
4
|
Bhattacharjee A, Ghosh S, Chatterji A, Chakraborty K. Neuron-glia: understanding cellular copper homeostasis, its cross-talk and their contribution towards neurodegenerative diseases. Metallomics 2020; 12:1897-1911. [PMID: 33295934 DOI: 10.1039/d0mt00168f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Over the years, the mechanism of copper homeostasis in various organ systems has gained importance. This is owing to the involvement of copper in a wide range of genetic disorders, most of them involving neurological symptoms. This highlights the importance of copper and its tight regulation in a complex organ system like the brain. It demands understanding the mechanism of copper acquisition and delivery to various cell types overcoming the limitation imposed by the blood brain barrier. The present review aims to investigate the existing work to understand the mechanism and complexity of cellular copper homeostasis in the two major cell types of the CNS - the neurons and the astrocytes. It investigates the mechanism of copper uptake, incorporation and export by these cell types. Furthermore, it brings forth the common as well as the exclusive aspects of neuronal and glial copper homeostasis including the studies from copper-based sensors. Glia act as a mediator of copper supply between the endothelium and the neurons. They possess all the qualifications of acting as a 'copper-sponge' for supply to the neurons. The neurons, on the other hand, require copper for various essential functions like incorporation as a cofactor for enzymes, synaptogenesis, axonal extension, inhibition of postsynaptic excitotoxicity, etc. Lastly, we also aim to understand the neuronal and glial pathology in various copper homeostasis disorders. The etiology of glial pathology and its contribution towards neuronal pathology and vice versa underlies the complexity of the neuropathology associated with the copper metabolism disorders.
Collapse
Affiliation(s)
- Ashima Bhattacharjee
- Amity Institute of Biotechnology, Amity University, Plot No: 36, 37 & 38, Major Arterial Road, Action Area II, Kadampukur Village, Rajarhat, Newtown, Kolkata, West Bengal 700135, India.
| | | | | | | |
Collapse
|
5
|
Gualandi F, Sette E, Fortunato F, Bigoni S, De Grandis D, Scotton C, Selvatici R, Neri M, Incensi A, Liguori R, Storbeck M, Karakaya M, Simioni V, Squarzoni S, Timmerman V, Wirth B, Donadio V, Tugnoli V, Ferlini A. Report of a novel ATP7A mutation causing distal motor neuropathy. Neuromuscul Disord 2019; 29:776-785. [DOI: 10.1016/j.nmd.2019.08.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 08/09/2019] [Accepted: 08/20/2019] [Indexed: 01/26/2023]
|
6
|
Bhattacharjee A, Chakraborty K, Shukla A. Cellular copper homeostasis: current concepts on its interplay with glutathione homeostasis and its implication in physiology and human diseases. Metallomics 2018; 9:1376-1388. [PMID: 28675215 DOI: 10.1039/c7mt00066a] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Copper is a trace element essential for almost all living organisms. But the level of intracellular copper needs to be tightly regulated. Dysregulation of cellular copper homeostasis leading to various diseases demonstrates the importance of this tight regulation. Copper homeostasis is regulated not only within the cell but also within individual intracellular compartments. Inactivation of export machinery results in excess copper being redistributed into various intracellular organelles. Recent evidence suggests the involvement of glutathione in playing an important role in regulating copper entry and intracellular copper homeostasis. Therefore interplay of both homeostases might play an important role within the cell. Similar to copper, glutathione balance is tightly regulated within individual cellular compartments. This review explores the existing literature on the role of glutathione in regulating cellular copper homeostasis. On the one hand, interplay of glutathione and copper homeostasis performs an important role in normal physiological processes, for example neuronal differentiation. On the other hand, perturbation of the interplay might play a key role in the pathogenesis of copper homeostasis disorders.
Collapse
|
7
|
Kanthlal SK, Joseph J, Baskaran Pillai AK, Padma UD. Neural effects in copper deficient Menkes disease: ATP7A-a distinctive marker. ASIAN PACIFIC JOURNAL OF TROPICAL DISEASE 2016. [DOI: 10.1016/s2222-1808(16)61107-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
8
|
Squitti R, Siotto M, Arciello M, Rossi L. Non-ceruloplasmin bound copper and ATP7B gene variants in Alzheimer's disease. Metallomics 2016; 8:863-73. [DOI: 10.1039/c6mt00101g] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
ATP7B, a protein mainly expressed in the hepatocytes, is a copper chaperone that loads the metal into the serum copper–protein ceruloplasmin during its synthesis and also escorts superfluous copper into the bile, by a sophisticated trafficking mechanism.
Collapse
Affiliation(s)
- R. Squitti
- Molecular Markers Laboratory
- IRCCS Istituto Centro San Giovanni di Dio-Fatebenefratelli
- 25125 Brescia, Italy
| | - M. Siotto
- Don Carlo Gnocchi ONLUS Foundation
- Milan, Italy
| | - M. Arciello
- Department of Biology
- University of Rome Tor Vergata
- Rome, Italy
| | - L. Rossi
- Department of Biology
- University of Rome Tor Vergata
- Rome, Italy
- Consorzio Interuniversitario “Istituto Nazionale Biostrutture e Biosistemi” (I.N.B.B.)
- Rome, Italy
| |
Collapse
|
9
|
Lenartowicz M, Krzeptowski W, Lipiński P, Grzmil P, Starzyński R, Pierzchała O, Møller LB. Mottled Mice and Non-Mammalian Models of Menkes Disease. Front Mol Neurosci 2015; 8:72. [PMID: 26732058 PMCID: PMC4684000 DOI: 10.3389/fnmol.2015.00072] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Accepted: 11/06/2015] [Indexed: 12/27/2022] Open
Abstract
Menkes disease is a multi-systemic copper metabolism disorder caused by mutations in the X-linked ATP7A gene and characterized by progressive neurodegeneration and severe connective tissue defects. The ATP7A protein is a copper (Cu)-transporting ATPase expressed in all tissues and plays a critical role in the maintenance of copper homeostasis in cells of the whole body. ATP7A participates in copper absorption in the small intestine and in copper transport to the central nervous system (CNS) across the blood-brain-barrier (BBB) and blood–cerebrospinal fluid barrier (BCSFB). Cu is essential for synaptogenesis and axonal development. In cells, ATP7A participates in the incorporation of copper into Cu-dependent enzymes during the course of its maturation in the secretory pathway. There is a high degree of homology (>80%) between the human ATP7A and murine Atp7a genes. Mice with mutations in the Atp7a gene, called mottled mutants, are well-established and excellent models of Menkes disease. Mottled mutants closely recapitulate the Menkes phenotype and are invaluable for studying Cu-metabolism. They provide useful models for exploring and testing new forms of therapy in Menkes disease. Recently, non-mammalian models of Menkes disease, Drosophila melanogaster and Danio rerio mutants were used in experiments which would be technically difficult to carry out in mammals.
Collapse
Affiliation(s)
- Małgorzata Lenartowicz
- Department of Genetics and Evolution, Institute of Zoology, Jagiellonian University Kraków, Poland
| | - Wojciech Krzeptowski
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Kraków, Poland
| | - Paweł Lipiński
- Department of Molecular Biology, Institute of Genetics and Animal Breeding, Polish Academy of Sciences Wólka Kosowska, Poland
| | - Paweł Grzmil
- Department of Genetics and Evolution, Institute of Zoology, Jagiellonian University Kraków, Poland
| | - Rafał Starzyński
- Department of Molecular Biology, Institute of Genetics and Animal Breeding, Polish Academy of Sciences Wólka Kosowska, Poland
| | - Olga Pierzchała
- Department of Genetics and Evolution, Institute of Zoology, Jagiellonian University Kraków, Poland
| | - Lisbeth Birk Møller
- Applied Human Molecular Genetics, Kennedy Center, Rigshospitalet, Copenhagen University Hospital Glostrup, Denmark
| |
Collapse
|
10
|
Visualizing APP and BACE-1 approximation in neurons yields insight into the amyloidogenic pathway. Nat Neurosci 2015; 19:55-64. [PMID: 26642089 PMCID: PMC4782935 DOI: 10.1038/nn.4188] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Accepted: 11/04/2015] [Indexed: 11/24/2022]
Abstract
Cleavage of APP (amyloid precursor protein) by BACE-1 (β-site APP cleaving enzyme-1) is the rate-limiting step in amyloid-beta (Aβ) production and a neuropathologic hallmark of Alzheimer's disease (AD); thus physical approximation of this substrate-enzyme pair is a critical event with broad biological and therapeutic implications. Despite much research, neuronal locales of APP/BACE-1 convergence and APP-cleavage remain unclear. Here we report an optical assay – based on fluorescence complementation – to visualize in-cellulo APP/BACE-1 interactions as a simple on/off signal. Combined with other assays tracking the fate of internalized APP in hippocampal neurons, we found that APP/BACE-1 interact in both biosynthetic and endocytic compartments; particularly along recycling-microdomains such as dendritic spines and presynaptic boutons. In axons, APP and BACE-1 are co-transported, and also interact during transit. Finally, our assay reveals that the AD-protective “Icelandic” mutation greatly attenuates APP/BACE-1 interactions, suggesting a mechanistic basis for protection. Collectively, the data challenge canonical models and provide concrete insights into long-standing controversies in the field.
Collapse
|
11
|
Ganguly A, Tang Y, Wang L, Ladt K, Loi J, Dargent B, Leterrier C, Roy S. A dynamic formin-dependent deep F-actin network in axons. J Cell Biol 2015. [PMID: 26216902 PMCID: PMC4523607 DOI: 10.1083/jcb.201506110] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Although actin at neuronal growth cones is well-studied, much less is known about actin organization and dynamics along axon shafts and presynaptic boutons. Using probes that selectively label filamentous-actin (F-actin), we found focal "actin hotspots" along axons-spaced ∼3-4 µm apart-where actin undergoes continuous assembly/disassembly. These foci are a nidus for vigorous actin polymerization, generating long filaments spurting bidirectionally along axons-a phenomenon we call "actin trails." Super-resolution microscopy reveals intra-axonal deep actin filaments in addition to the subplasmalemmal "actin rings" described recently. F-actin hotspots colocalize with stationary axonal endosomes, and blocking vesicle transport diminishes the actin trails, suggesting mechanistic links between vesicles and F-actin kinetics. Actin trails are formin-but not Arp2/3-dependent and help enrich actin at presynaptic boutons. Finally, formin inhibition dramatically disrupts synaptic recycling. Collectively, available data suggest a two-tier F-actin organization in axons, with stable "actin rings" providing mechanical support to the plasma membrane and dynamic "actin trails" generating a flexible cytoskeletal network with putative physiological roles.
Collapse
Affiliation(s)
- Archan Ganguly
- Department of Pathology, University of California, San Diego, La Jolla, CA 92093
| | - Yong Tang
- Department of Pathology, University of California, San Diego, La Jolla, CA 92093
| | - Lina Wang
- Department of Pathology, University of California, San Diego, La Jolla, CA 92093
| | - Kelsey Ladt
- Department of Pathology, University of California, San Diego, La Jolla, CA 92093 Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093
| | - Jonathan Loi
- Department of Pathology, University of California, San Diego, La Jolla, CA 92093
| | - Bénédicte Dargent
- Aix Marseille Université, Centre National de la Recherche Scientifique, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille (CRN2M) UMR7286, 13344 Marseille, France
| | - Christophe Leterrier
- Aix Marseille Université, Centre National de la Recherche Scientifique, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille (CRN2M) UMR7286, 13344 Marseille, France
| | - Subhojit Roy
- Department of Pathology, University of California, San Diego, La Jolla, CA 92093 Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093
| |
Collapse
|
12
|
D'Ambrosi N, Rossi L. Copper at synapse: Release, binding and modulation of neurotransmission. Neurochem Int 2015; 90:36-45. [PMID: 26187063 DOI: 10.1016/j.neuint.2015.07.006] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 06/30/2015] [Accepted: 07/10/2015] [Indexed: 10/23/2022]
Abstract
Over the last decade, a piece of the research studying copper role in biological systems was devoted to unravelling a still elusive, but extremely intriguing, aspect that is the involvement of copper in synaptic function. These studies were prompted to provide a rationale to the finding that copper is released in the synaptic cleft upon depolarization. The copper pump ATP7A, which mutations are responsible for diseases with a prominent neurodegenerative component, seems to play a pivotal role in the release of copper at synapses. Furthermore, it was found that, when in the synaptic cleft, copper can control, directly or indirectly, the activity of the neurotransmitter receptors (NMDA, AMPA, GABA, P2X receptors), thus affecting excitability. In turn, neurotransmission can affect copper trafficking and delivery in neuronal cells. Furthermore, it was reported that copper can also modulate synaptic vesicles trafficking and the interaction between proteins of the secretory pathways. Interestingly, proteins with a still unclear role in neuronal system though associated with the pathogenesis of neurodegenerative diseases (the amyloid precursor protein, APP, the prion protein, PrP, α-synuclein, α-syn) show copper-binding domains. They may act as copper buffer at synapses and participate in the interplay between copper and the neurotransmitters receptors. Given that copper dysmetabolism occurs in several diseases affecting central and peripheral nervous system, the findings on the contribution of copper in synaptic transmission, beside its more consolidate role as a neuronal enzymes cofactor, may open new insights for therapy interventions.
Collapse
Affiliation(s)
- Nadia D'Ambrosi
- Institute of Anatomy and Cell Biology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Luisa Rossi
- Department of Biology, University of Rome Tor Vergata, Rome, Italy.
| |
Collapse
|
13
|
Takikita S, Takano T, Narita T, Maruo Y. Increased apoptosis and hypomyelination in cerebral white matter of macular mutant mouse brain. Mol Genet Metab Rep 2015; 4:25-9. [PMID: 26937406 PMCID: PMC4750634 DOI: 10.1016/j.ymgmr.2015.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 05/25/2015] [Indexed: 12/18/2022] Open
Abstract
Hypomyelination in developing brain is often accompanied by congenital metabolic disorders. Menkes kinky hair disease is an X-linked neurodegenerative disease of impaired copper transport, resulting from a mutation of the Menkes disease gene, a transmembrane copper-transporting p-type ATPase gene (ATP7A). In a macular mutant mouse model, the murine ortholog of Menkes gene (mottled gene) is mutated, and widespread neurodegeneration and subsequent death are observed. Although some biochemical analysis of myelin protein in macular mouse has been reported, detailed histological study of myelination in this mouse model is currently lacking. Since myelin abnormality is one of the neuropathologic findings of human Menkes disease, in this study early myelination in macular mouse brain was evaluated by immunohistochemistry. Two-week-old macular mice and normal littermates were perfused with 4% paraformaldehyde. Immunohistochemical staining of paraffin embedded and vibratome sections was performed using antibodies against either CNPase, cleaved caspase-3 or O4 (marker of immature oligodendrocytes). This staining showed that cerebral myelination in macular mouse was generally hypoplastic and that hypomyelination was remarkable in internal capsule, corpus callosum, and cingulate cortex. In addition, an increased number of cleaved caspase-3 positive cells were observed in corpus callosum and internal capsule. Copper deficiency induced by low copper diet has been reported to induce oligodendrocyte dysfunction and leads to hypomyelination in this mouse model. Taken together, hypomyelination observed in this study in a mouse model of Menkes disease is assumed to be induced by increased apoptosis of immature oligodendrocytes in developing cerebrum, through deficient intracellular copper metabolism.
Collapse
Affiliation(s)
- Shoichi Takikita
- Department of Pediatrics, Takatsuki Red Cross Hospital, Takatsuki 569-1096, Japan
| | - Tomoyuki Takano
- Department of Pediatrics, Shiga University of Medical Science, Otsu 520-2192, Japan
| | - Tsutomu Narita
- Department of Pediatrics, Takatsuki Red Cross Hospital, Takatsuki 569-1096, Japan
| | - Yoshihiro Maruo
- Department of Pediatrics, Shiga University of Medical Science, Otsu 520-2192, Japan
| |
Collapse
|
14
|
Scheiber IF, Mercer JF, Dringen R. Metabolism and functions of copper in brain. Prog Neurobiol 2014; 116:33-57. [DOI: 10.1016/j.pneurobio.2014.01.002] [Citation(s) in RCA: 213] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 01/08/2014] [Accepted: 01/08/2014] [Indexed: 12/15/2022]
|
15
|
Gaier ED, Eipper BA, Mains RE. Pam heterozygous mice reveal essential role for Cu in amygdalar behavioral and synaptic function. Ann N Y Acad Sci 2014; 1314:15-23. [PMID: 24593825 DOI: 10.1111/nyas.12378] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Copper (Cu) is an essential element with many biological roles, but its roles in the mammalian nervous system are poorly understood. Mice deficient in the cuproenzyme peptidylglycine α-amidating monooxygenase (Pam(+/-) mice) were initially generated to study neuropeptide amidation. Pam(+/-) mice exhibit profound deficits in a few behavioral tasks, including enhancements in innate fear along with deficits in acquired fear. Interestingly, several Pam(+/-) phenotypes were recapitulated in Cu-restricted wild-type mice and rescued in Cu-supplemented Pam(+/-) mice. These behaviors correspond to enhanced excitability and deficient synaptic plasticity in the amygdala of Pam(+/-) mice, which are also rescued by Cu supplementation. Cu and ATP7A are present at synapses, in key positions to respond to and influence synaptic activity. Further study demonstrated that extracellular Cu is necessary for wild-type synaptic plasticity and sufficient to induce long-term potentiation. These experiments support roles for PAM in Cu homeostasis and for synaptic Cu in amygdalar function.
Collapse
Affiliation(s)
- Eric D Gaier
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut
| | | | | |
Collapse
|
16
|
Bica L, Liddell JR, Donnelly PS, Duncan C, Caragounis A, Volitakis I, Paterson BM, Cappai R, Grubman A, Camakaris J, Crouch PJ, White AR. Neuroprotective copper bis(thiosemicarbazonato) complexes promote neurite elongation. PLoS One 2014; 9:e90070. [PMID: 24587210 PMCID: PMC3938583 DOI: 10.1371/journal.pone.0090070] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 01/29/2014] [Indexed: 11/19/2022] Open
Abstract
Abnormal biometal homeostasis is a central feature of many neurodegenerative disorders including Alzheimer's disease (AD), Parkinson's disease (PD), and motor neuron disease. Recent studies have shown that metal complexing compounds behaving as ionophores such as clioquinol and PBT2 have robust therapeutic activity in animal models of neurodegenerative disease; however, the mechanism of neuroprotective action remains unclear. These neuroprotective or neurogenerative processes may be related to the delivery or redistribution of biometals, such as copper and zinc, by metal ionophores. To investigate this further, we examined the effect of the bis(thiosemicarbazonato)-copper complex, Cu(II)(gtsm) on neuritogenesis and neurite elongation (neurogenerative outcomes) in PC12 neuronal-related cultures. We found that Cu(II)(gtsm) induced robust neurite elongation in PC12 cells when delivered at concentrations of 25 or 50 nM overnight. Analogous effects were observed with an alternative copper bis(thiosemicarbazonato) complex, Cu(II)(atsm), but at a higher concentration. Induction of neurite elongation by Cu(II)(gtsm) was restricted to neurites within the length range of 75-99 µm with a 2.3-fold increase in numbers of neurites in this length range with 50 nM Cu(II)(gtsm) treatment. The mechanism of neurogenerative action was investigated and revealed that Cu(II)(gtsm) inhibited cellular phosphatase activity. Treatment of cultures with 5 nM FK506 (calcineurin phosphatase inhibitor) resulted in analogous elongation of neurites compared to 50 nM Cu(II)(gtsm), suggesting a potential link between Cu(II)(gtsm)-mediated phosphatase inhibition and neurogenerative outcomes.
Collapse
Affiliation(s)
- Laura Bica
- Department of Pathology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Jeffrey R. Liddell
- Department of Pathology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Paul S. Donnelly
- Bio21 Molecular Science and Biotechnology Institute, Parkville, Victoria, Australia
- School of Chemistry, The University of Melbourne, Melbourne, Victoria, Australia
| | - Clare Duncan
- Department of Pathology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Aphrodite Caragounis
- Department of Pathology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Irene Volitakis
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Brett M. Paterson
- Bio21 Molecular Science and Biotechnology Institute, Parkville, Victoria, Australia
- School of Chemistry, The University of Melbourne, Melbourne, Victoria, Australia
| | - Roberto Cappai
- Department of Pathology, The University of Melbourne, Melbourne, Victoria, Australia
- Bio21 Molecular Science and Biotechnology Institute, Parkville, Victoria, Australia
| | - Alexandra Grubman
- Department of Pathology, The University of Melbourne, Melbourne, Victoria, Australia
| | - James Camakaris
- Department of Genetics, The University of Melbourne, Melbourne, Victoria, Australia
| | - Peter J. Crouch
- Department of Pathology, The University of Melbourne, Melbourne, Victoria, Australia
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Anthony R. White
- Department of Pathology, The University of Melbourne, Melbourne, Victoria, Australia
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- * E-mail:
| |
Collapse
|
17
|
Hwang JEC, de Bruyne M, Warr CG, Burke R. Copper overload and deficiency both adversely affect the central nervous system of Drosophila. Metallomics 2014; 6:2223-9. [DOI: 10.1039/c4mt00140k] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Ectopic neuronal copper efflux causes a functional copper deficiency leading to developmental lethality in Drosophila.
Collapse
Affiliation(s)
| | | | - Coral G. Warr
- School of Biological Sciences
- Monash University
- Australia
| | - Richard Burke
- School of Biological Sciences
- Monash University
- Australia
| |
Collapse
|
18
|
Hatori Y, Lutsenko S. An expanding range of functions for the copper chaperone/antioxidant protein Atox1. Antioxid Redox Signal 2013; 19:945-57. [PMID: 23249252 PMCID: PMC3763234 DOI: 10.1089/ars.2012.5086] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
SIGNIFICANCE Antioxidant protein 1 (Atox1 in human cells) is a copper chaperone for the copper export pathway with an essential role in cellular copper distribution. In vitro, Atox1 binds and transfers copper to the copper-transporting ATPases, stimulating their catalytic activity. Inactivation of Atox1 in cells inhibits maturation of secreted cuproenzymes as well as copper export from cells. RECENT ADVANCES Accumulating data suggest that cellular functions of Atox1 are not limited to its copper-trafficking role and may include storage of labile copper, modulation of transcription, and antioxidant defense. The conserved metal binding site of Atox1, CxGC, differs from the metal-binding sites of copper-transporting ATPases and has a physiologically relevant redox potential that equilibrates with the GSH:GSSG pair. CRITICAL ISSUES Tight relationship appears to exist between intracellular copper levels and glutathione (GSH) homeostasis. The biochemical properties of Atox1 place it at the intersection of cellular networks that regulate copper distribution and cellular redox balance. Mechanisms through which Atox1 facilitates copper export and contributes to oxidative defense are not fully understood. FUTURE DIRECTIONS The current picture of cellular redox homeostasis and copper physiology will be enhanced by further mechanistic studies of functional interactions between the GSH:GSSG pair and copper-trafficking machinery.
Collapse
Affiliation(s)
- Yuta Hatori
- Department of Physiology, Johns Hopkins University, Baltimore, MD 21205, USA
| | | |
Collapse
|
19
|
Telianidis J, Hung YH, Materia S, Fontaine SL. Role of the P-Type ATPases, ATP7A and ATP7B in brain copper homeostasis. Front Aging Neurosci 2013; 5:44. [PMID: 23986700 PMCID: PMC3750203 DOI: 10.3389/fnagi.2013.00044] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 08/05/2013] [Indexed: 12/21/2022] Open
Abstract
Over the past two decades there have been significant advances in our understanding of copper homeostasis and the pathological consequences of copper dysregulation. Cumulative evidence is revealing a complex regulatory network of proteins and pathways that maintain copper homeostasis. The recognition of copper dysregulation as a key pathological feature in prominent neurodegenerative disorders such as Alzheimer's, Parkinson's, and prion diseases has led to increased research focus on the mechanisms controlling copper homeostasis in the brain. The copper-transporting P-type ATPases (copper-ATPases), ATP7A and ATP7B, are critical components of the copper regulatory network. Our understanding of the biochemistry and cell biology of these complex proteins has grown significantly since their discovery in 1993. They are large polytopic transmembrane proteins with six copper-binding motifs within the cytoplasmic N-terminal domain, eight transmembrane domains, and highly conserved catalytic domains. These proteins catalyze ATP-dependent copper transport across cell membranes for the metallation of many essential cuproenzymes, as well as for the removal of excess cellular copper to prevent copper toxicity. A key functional aspect of these copper transporters is their copper-responsive trafficking between the trans-Golgi network and the cell periphery. ATP7A- and ATP7B-deficiency, due to genetic mutation, underlie the inherited copper transport disorders, Menkes and Wilson diseases, respectively. Their importance in maintaining brain copper homeostasis is underscored by the severe neuropathological deficits in these disorders. Herein we will review and update our current knowledge of these copper transporters in the brain and the central nervous system, their distribution and regulation, their role in normal brain copper homeostasis, and how their absence or dysfunction contributes to disturbances in copper homeostasis and neurodegeneration.
Collapse
Affiliation(s)
- Jonathon Telianidis
- Strategic Research Centre for Molecular and Medical Research, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
| | - Ya Hui Hung
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental HealthParkville, VIC, Australia
- Centre for Neuroscience Research, The University of MelbourneParkville, VIC, Australia
| | - Stephanie Materia
- Strategic Research Centre for Molecular and Medical Research, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
| | - Sharon La Fontaine
- Strategic Research Centre for Molecular and Medical Research, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
| |
Collapse
|
20
|
Hung YH, Bush AI, La Fontaine S. Links between copper and cholesterol in Alzheimer's disease. Front Physiol 2013; 4:111. [PMID: 23720634 PMCID: PMC3655288 DOI: 10.3389/fphys.2013.00111] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 04/30/2013] [Indexed: 01/01/2023] Open
Abstract
Altered copper homeostasis and hypercholesterolemia have been identified independently as risk factors for Alzheimer's disease (AD). Abnormal copper and cholesterol metabolism are implicated in the genesis of amyloid plaques and neurofibrillary tangles (NFT), which are two key pathological signatures of AD. Amyloidogenic processing of a sub-population of amyloid precursor protein (APP) that produces Aβ occurs in cholesterol-rich lipid rafts in copper deficient AD brains. Co-localization of Aβ and a paradoxical high concentration of copper in lipid rafts fosters the formation of neurotoxic Aβ:copper complexes. These complexes can catalytically oxidize cholesterol to generate H2O2, oxysterols and other lipid peroxidation products that accumulate in brains of AD cases and transgenic mouse models. Tau, the core protein component of NFTs, is sensitive to interactions with copper and cholesterol, which trigger a cascade of hyperphosphorylation and aggregation preceding the generation of NFTs. Here we present an overview of copper and cholesterol metabolism in the brain, and how their integrated failure contributes to development of AD.
Collapse
Affiliation(s)
- Ya Hui Hung
- Oxidation Biology Laboratory, Florey Institute of Neuroscience and Mental Health Parkville, VIC, Australia ; Centre for Neuroscience Research, The University of Melbourne Parkville, VIC, Australia
| | | | | |
Collapse
|
21
|
Electro-clinical features and magnetic resonance imaging correlates in Menkes disease. Brain Dev 2013; 35:398-405. [PMID: 22921468 DOI: 10.1016/j.braindev.2012.07.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Revised: 07/20/2012] [Accepted: 07/24/2012] [Indexed: 11/22/2022]
Abstract
BACKGROUND Epilepsy is an early and important feature in Menkes disease (MD), an X-linked recessive neurodegenerative disorder of childhood with defect in copper metabolism. There are only few reports on the electro-clinical and magnetic resonance imaging correlates in Menkes disease. The current study describes the electro-clinical features in MD in relation with the structural findings on MRI. PATIENTS AND METHODS Six patients from five families were evaluated between 2005 and 2011. Their diagnosis was based on the characteristic morphological features, microscopic evidence of pili torti and low copper and ceruloplasmin levels. All the patients underwent MRI and EEG as part of the evaluation. RESULTS All patients had classical form of MD with typical morphological features. All but one patient had refractory seizures. Seizure types included multifocal clonic seizures (n=3), myoclonic jerks (n=4) and tonic spasms (n=1). EEG was markedly abnormal in all except in the patient without clinical seizures. While focal epileptiform discharges predominated before six months of age modified hypsarrhythmia was characteristically noted thereafter. MR Imaging revealed abnormalities in all patients, with cerebral atrophy and delayed myelination being the most common observations. Other features noted were subdural effusion (n=3), leukoencephalopathy (n=3) and basal ganglia signal changes (n=1). Follow up imaging in three patients showed resolution of white matter signal intensity changes. CONCLUSIONS Electro-clinical features in Menkes disease are age dependent and evolve sequentially. White matter changes coincided with acute exacerbation of seizures. There was fair correlation between the electro-clinical features and structural findings on MRI.
Collapse
|
22
|
ATP7A gene addition to the choroid plexus results in long-term rescue of the lethal copper transport defect in a Menkes disease mouse model. Mol Ther 2011; 19:2114-23. [PMID: 21878905 DOI: 10.1038/mt.2011.143] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Menkes disease is a lethal infantile neurodegenerative disorder of copper metabolism caused by mutations in a P-type ATPase, ATP7A. Currently available treatment (daily subcutaneous copper injections) is not entirely effective in the majority of affected individuals. The mottled-brindled (mo-br) mouse recapitulates the Menkes phenotype, including abnormal copper transport to the brain owing to mutation in the murine homolog, Atp7a, and dies by 14 days of age. We documented that mo-br mice on C57BL/6 background were not rescued by peripheral copper administration, and used this model to evaluate brain-directed therapies. Neonatal mo-br mice received lateral ventricle injections of either adeno-associated virus serotype 5 (AAV5) harboring a reduced-size human ATP7A (rsATP7A) complementary DNA (cDNA), copper chloride, or both. AAV5-rsATP7A showed selective transduction of choroid plexus epithelia and AAV5-rsATP7A plus copper combination treatment rescued mo-br mice; 86% survived to weaning (21 days), median survival increased to 43 days, 37% lived beyond 100 days, and 22% survived to the study end point (300 days). This synergistic treatment effect correlated with increased brain copper levels, enhanced activity of dopamine-β-hydroxylase, a copper-dependent enzyme, and correction of brain pathology. Our findings provide the first definitive evidence that gene therapy may have clinical utility in the treatment of Menkes disease.
Collapse
|
23
|
Abstract
This Review summarizes recent advances in understanding copper-transporting ATPase 1 (ATP7A), and examines the neurological phenotypes associated with dysfunction of this protein. Involvement of ATP7A in axonal outgrowth, synapse integrity and neuronal activation underscores the fundamental importance of copper metabolism to neurological function. Defects in ATP7A cause Menkes disease, an infantile-onset, lethal condition. Neonatal diagnosis and early treatment with copper injections enhance survival in patients with this disease, and can normalize clinical outcomes if mutant ATP7A molecules retain small amounts of residual activity. Gene replacement rescues a mouse model of Menkes disease, suggesting a potential therapeutic approach for patients with complete loss-of-function ATP7A mutations. Remarkably, a newly discovered ATP7A disorder-isolated distal motor neuropathy-has none of the characteristic clinical or biochemical abnormalities of Menkes disease or its milder allelic variant occipital horn syndrome (OHS), instead resembling Charcot-Marie-Tooth disease type 2. These findings indicate that ATP7A has a crucial but previously unappreciated role in motor neuron maintenance, and that the mechanism underlying ATP7A-related distal motor neuropathy is distinct from Menkes disease and OHS pathophysiology. Collectively, these insights refine our knowledge of the neurology of ATP7A-related copper transport diseases and pave the way for further progress in understanding ATP7A function.
Collapse
|
24
|
Calcium-dependent copper redistributions in neuronal cells revealed by a fluorescent copper sensor and X-ray fluorescence microscopy. Proc Natl Acad Sci U S A 2011; 108:5980-5. [PMID: 21444780 DOI: 10.1073/pnas.1009932108] [Citation(s) in RCA: 148] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Dynamic fluxes of s-block metals like potassium, sodium, and calcium are of broad importance in cell signaling. In contrast, the concept of mobile transition metals triggered by cell activation remains insufficiently explored, in large part because metals like copper and iron are typically studied as static cellular nutrients and there are a lack of direct, selective methods for monitoring their distributions in living cells. To help meet this need, we now report Coppersensor-3 (CS3), a bright small-molecule fluorescent probe that offers the unique capability to image labile copper pools in living cells at endogenous, basal levels. We use this chemical tool in conjunction with synchotron-based microprobe X-ray fluorescence microscopy (XRFM) to discover that neuronal cells move significant pools of copper from their cell bodies to peripheral processes upon their activation. Moreover, further CS3 and XRFM imaging experiments show that these dynamic copper redistributions are dependent on calcium release, establishing a link between mobile copper and major cell signaling pathways. By providing a small-molecule fluorophore that is selective and sensitive enough to image labile copper pools in living cells under basal conditions, CS3 opens opportunities for discovering and elucidating functions of copper in living systems.
Collapse
|
25
|
Vallipuram J, Grenville J, Crawford DA. The E646D-ATP13A4 mutation associated with autism reveals a defect in calcium regulation. Cell Mol Neurobiol 2010; 30:233-46. [PMID: 19731010 DOI: 10.1007/s10571-009-9445-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Accepted: 08/17/2009] [Indexed: 11/24/2022]
Abstract
ATP13A4 is a member of the subfamily of P5-type ATPases. P5-type ATPases are the least studied of the P-type ATPase subfamilies with no ion specificities assigned to them. In order to elucidate ATP13A4 function, we studied the protein's subcellular localization and tested whether it is involved in calcium regulation. The intracellular calcium concentration was measured in COS-7 cells over-expressing mouse ATP13A4 using ratiometric calcium imaging with fura-2 AM as a calcium indicator. The results of this study show that ATP13A4 is localized to the endoplasmic reticulum (ER). Furthermore, we demonstrate that over-expression of ATP13A4 in COS-7 cells caused a significant increase in the intracellular calcium level. Interestingly, over-expression of the sequence variant containing a substitution of aspartic acid for a glutamic acid (E646D), previously found in patients with autism spectrum disorder (ASD), did not increase the free cellular calcium likely due to the mutation. In this study, we also describe the expression of ATP13A4 during mouse embryonic development. Quantitative real-time PCR revealed that ATP13A4 was highly expressed at embryonic days 15-17, when neurogenesis takes place. The present study is the first to provide further insights into the biological role of a P5-type ATPase. Our results demonstrate that ATP13A4 may be involved in calcium regulation and that its expression is developmentally regulated. Overall, this study provides support for the hypothesis that ATP13A4 may play a vital role in the developing nervous system and its impairment can contribute to the symptoms seen in ASD.
Collapse
|
26
|
Perinatal copper deficiency alters rat cerebellar purkinje cell size and distribution. THE CEREBELLUM 2010; 9:136-44. [PMID: 19838760 DOI: 10.1007/s12311-009-0136-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Copper is required for activity of several key enzymes and for optimal mammalian development, especially within the central nervous system. Copper-deficient (CuD) animals are visibly ataxic, and previous studies in rats have demonstrated impaired motor function through behavioral experiments consistent with altered cerebellar development. Perinatal copper deficiency was produced in Holtzman rat dams by restricting dietary copper during the last two thirds of gestation and lactation. Male offspring were evaluated at postnatal day 25. Compared to cerebella from copper-adequate pups, the CuD pups had larger Purkinje cell (PC) size and irregularities in the Purkinje cell monolayer. These results suggest that the ataxic behavioral phenotype of CuD rats may result from disrupted inhibitory pathways in the cerebellum. A similar PC phenotype is seen in Menkes disease and in mottled mouse mutants with genetic copper deficiency, suggesting that copper deficiency and not just specific loss of ATP7A function is responsible.
Collapse
|
27
|
Lutsenko S, Bhattacharjee A, Hubbard AL. Copper handling machinery of the brain. Metallomics 2010; 2:596-608. [DOI: 10.1039/c0mt00006j] [Citation(s) in RCA: 156] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
28
|
Copper in the brain and Alzheimer’s disease. J Biol Inorg Chem 2009; 15:61-76. [DOI: 10.1007/s00775-009-0600-y] [Citation(s) in RCA: 313] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2009] [Accepted: 10/13/2009] [Indexed: 12/13/2022]
|
29
|
Gajewska A, Gajkowska B, Pajak B, Styrna J, Kochman K. Impaired growth hormone-releasing hormone neurons ultrastructure and peptide accumulation in the arcuate nucleus of mosaic mice with altered copper metabolism. Brain Res Bull 2009; 80:128-32. [DOI: 10.1016/j.brainresbull.2009.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Accepted: 04/07/2009] [Indexed: 01/31/2023]
|
30
|
Bohlken A, Cheung BB, Bell JL, Koach J, Smith S, Sekyere E, Thomas W, Norris M, Haber M, Lovejoy DB, Richardson DR, Marshall GM. ATP7A is a novel target of retinoic acid receptor beta2 in neuroblastoma cells. Br J Cancer 2009; 100:96-105. [PMID: 19127267 PMCID: PMC2634674 DOI: 10.1038/sj.bjc.6604833] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Increased retinoic acid receptor β (RARβ2) gene expression is a hallmark of cancer cell responsiveness to retinoid anticancer effects. Moreover, low basal or induced RARβ2 expression is a common feature of many human cancers, suggesting that RARβ2 may act as a tumour suppressor gene in the absence of supplemented retinoid. We have previously shown that low RARβ2 expression is a feature of advanced neuroblastoma. Here, we demonstrate that the ABC domain of the RARβ2 protein alone was sufficient for the growth inhibitory effects of RARβ2 on neuroblastoma cells. ATP7A, the copper efflux pump, is a retinoid-responsive gene, was upregulated by ectopic overexpression of RARβ2. The ectopic overexpression of the RARβ2 ABC domain was sufficient to induce ATP7A expression, whereas, RARβ2 siRNA blocked the induction of ATP7A expression in retinoid-treated neuroblastoma cells. Forced downregulation of ATP7A reduced copper efflux and increased viability of retinoid-treated neuroblastoma cells. Copper supplementation enhanced cell growth and reduced retinoid-responsiveness, whereas copper chelation reduced the viability and proliferative capacity. Taken together, our data demonstrates ATP7A expression is regulated by retinoic acid receptor β and it has effects on intracellular copper levels, revealing a link between the anticancer action of retinoids and copper metabolism.
Collapse
Affiliation(s)
- A Bohlken
- Children's Cancer Institute Australia for Medical Research, Randwick, NSW 2031, Australia
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
The multi-layered regulation of copper translocating P-type ATPases. Biometals 2009; 22:177-90. [PMID: 19130269 DOI: 10.1007/s10534-008-9183-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Accepted: 12/07/2008] [Indexed: 12/21/2022]
Abstract
The copper-translocating Menkes (ATP7A, MNK protein) and Wilson (ATP7B, WND protein) P-type ATPases are pivotal for copper (Cu) homeostasis, functioning in the biosynthetic incorporation of Cu into copper-dependent enzymes of the secretory pathway, Cu detoxification via Cu efflux, and specialized roles such as systemic Cu absorption (MNK) and Cu excretion (WND). Essential to these functions is their Cu and hormone-responsive distribution between the trans-Golgi network (TGN) and exocytic vesicles located at or proximal to the apical (WND) or basolateral (MNK) cell surface. Intriguingly, MNK and WND Cu-ATPases expressed in the same tissues perform distinct yet complementary roles. While intramolecular differences may specify their distinct roles, cellular signaling components are predicted to be critical for both differences and synergy between these enzymes. This review focuses on these mechanisms, including the cell signaling pathways that influence trafficking and bi-functionality of Cu-ATPases. Phosphorylation events are hypothesized to play a central role in Cu homeostasis, promoting multi-layered regulation and cross-talk between cuproenzymes and Cu-independent mechanisms.
Collapse
|
32
|
Kambe T, Weaver BP, Andrews GK. The genetics of essential metal homeostasis during development. Genesis 2008; 46:214-28. [PMID: 18395838 DOI: 10.1002/dvg.20382] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The essential metals copper, zinc, and iron play key roles in embryonic, fetal, and postnatal development in higher eukaryotes. Recent advances in our understanding of the molecules involved in the intricate control of the homeostasis of these metals and the availability of natural mutations and targeted mutations in many of the genes involved have allowed for elucidation of the diverse roles of these metals during development. Evidence suggests that the ability of the embryo to control the homeostasis of these metals becomes essential at the blastocyst stage and during early morphogenesis. However, these metals play unique roles throughout development and exert pleiotropic, metal-specific, and often cell-specific effects on morphogenesis, growth, and differentiation. Herein, we briefly review the major players known to be involved in the homeostasis of each of these essential metals and their known roles in development.
Collapse
Affiliation(s)
- Taiho Kambe
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas 66160-7421, USA
| | | | | |
Collapse
|
33
|
Linz R, Lutsenko S. Copper-transporting ATPases ATP7A and ATP7B: cousins, not twins. J Bioenerg Biomembr 2008; 39:403-7. [PMID: 18000748 DOI: 10.1007/s10863-007-9101-2] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Copper plays an essential role in human physiology and is indispensable for normal growth and development. Enzymes that are involved in connective tissue formation, neurotransmitter biosynthesis, iron transport, and others essential physiological processes require copper as a cofactor to mediate their reactions. The biosynthetic incorporation of copper into these enzymes takes places within the secretory pathway and is critically dependent on the activity of copper-transporting ATPases ATP7A or ATP7B. In addition, ATP7A and ATP7B regulate intracellular copper concentration by removing excess copper from the cell. These two transporters belong to the family of P(1)-type ATPases, share significant sequence similarity, utilize the same general mechanism for their function, and show partial colocalization in some cells. However, the distinct biochemical characteristics and dissimilar trafficking properties of ATP7A and ATP7B in cells, in which they are co-expressed, indicate that specific functions of these two copper-transporting ATPases are not identical. Immuno-detection studies in cells and tissues have begun to suggest specific roles for ATP7A and ATP7B. These experiments also revealed technical challenges associated with quantitative detection of copper-transporting ATPases in tissues, as illustrated here by comparing the results of ATP7A and ATP7B immunodetection in mouse cerebellum.
Collapse
Affiliation(s)
- Rachel Linz
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR 97239, USA
| | | |
Collapse
|
34
|
Burke R, Commons E, Camakaris J. Expression and localisation of the essential copper transporter DmATP7 in Drosophila neuronal and intestinal tissues. Int J Biochem Cell Biol 2008; 40:1850-60. [PMID: 18321764 DOI: 10.1016/j.biocel.2008.01.021] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Revised: 01/08/2008] [Accepted: 01/17/2008] [Indexed: 11/17/2022]
Abstract
Copper homeostasis is achieved by a combination of regulated uptake, efflux and sequestration and is essential for animal health and viability. Transmembrane copper transport proteins of the P-type ATPase family play key roles in cellular copper efflux. Here, the transcriptional and post-translational regulation of DmATP7, the sole Drosophila melanogaster ortholog of the human MNK and WND copper transport genes, is examined. An enhancer element with sufficient regulatory information to rescue DmATP7 mutant flies to adulthood is identified. This regulatory element drives expression in all neuronal tissues examined and demonstrates copper-inducible, Mtf-1 dependent expression in the larval midgut. These results support an important functional role for copper transport in neuronal tissues and indicate that regulation of DmATP7 expression is not used to limit copper absorption in toxic copper conditions. Localisation of a functional EYFP-DmATP7 fusion protein is also examined. This fusion protein localises at or proximal to the basolateral membrane of DmATP7 expressing midgut cells supporting a role for DmATP7 in export of copper from midgut cells.
Collapse
Affiliation(s)
- Richard Burke
- School of Biological Sciences, Monash University, Victoria 3800, Australia.
| | | | | |
Collapse
|
35
|
Abstract
Copper and iron are transition elements essential for life. These metals are required to maintain the brain's biochemistry such that deficiency or excess of either copper or iron results in central nervous system disease. This review focuses on the inherited disorders in humans that directly affect copper or iron homeostasis in the brain. Elucidation of the molecular genetic basis of these rare disorders has provided insight into the mechanisms of copper and iron acquisition, trafficking, storage, and excretion in the brain. This knowledge permits a greater understanding of copper and iron roles in neurobiology and neurologic disease and may allow for the development of therapeutic approaches where aberrant metal homeostasis is implicated in disease pathogenesis.
Collapse
Affiliation(s)
- Erik Madsen
- Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri 63130, USA.
| | | |
Collapse
|
36
|
Lutsenko S, Barnes NL, Bartee MY, Dmitriev OY. Function and regulation of human copper-transporting ATPases. Physiol Rev 2007; 87:1011-46. [PMID: 17615395 DOI: 10.1152/physrev.00004.2006] [Citation(s) in RCA: 554] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Copper-transporting ATPases (Cu-ATPases) ATP7A and ATP7B are evolutionarily conserved polytopic membrane proteins with essential roles in human physiology. The Cu-ATPases are expressed in most tissues, and their transport activity is crucial for central nervous system development, liver function, connective tissue formation, and many other physiological processes. The loss of ATP7A or ATP7B function is associated with severe metabolic disorders, Menkes disease, and Wilson disease. In cells, the Cu-ATPases maintain intracellular copper concentration by transporting copper from the cytosol across cellular membranes. They also contribute to protein biosynthesis by delivering copper into the lumen of the secretory pathway where metal ion is incorporated into copper-dependent enzymes. The biosynthetic and homeostatic functions of Cu-ATPases are performed in different cell compartments; targeting to these compartments and the functional activity of Cu-ATPase are both regulated by copper. In recent years, significant progress has been made in understanding the structure, function, and regulation of these essential transporters. These studies raised many new questions related to specific physiological roles of Cu-ATPases in various tissues and complex mechanisms that control the Cu-ATPase function. This review summarizes current data on the structural organization and functional properties of ATP7A and ATP7B as well as their localization and functions in various tissues, and discusses the current models of regulated trafficking of human Cu-ATPases.
Collapse
Affiliation(s)
- Svetlana Lutsenko
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon 97239, USA.
| | | | | | | |
Collapse
|
37
|
La Fontaine S, Mercer JFB. Trafficking of the copper-ATPases, ATP7A and ATP7B: Role in copper homeostasis. Arch Biochem Biophys 2007; 463:149-67. [PMID: 17531189 DOI: 10.1016/j.abb.2007.04.021] [Citation(s) in RCA: 300] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2007] [Revised: 04/18/2007] [Accepted: 04/18/2007] [Indexed: 01/05/2023]
Abstract
Copper is essential for human health and copper imbalance is a key factor in the aetiology and pathology of several neurodegenerative diseases. The copper-transporting P-type ATPases, ATP7A and ATP7B are key molecules required for the regulation and maintenance of mammalian copper homeostasis. Their absence or malfunction leads to the genetically inherited disorders, Menkes and Wilson diseases, respectively. These proteins have a dual role in cells, namely to provide copper to essential cuproenzymes and to mediate the excretion of excess intracellular copper. A unique feature of ATP7A and ATP7B that is integral to these functions is their ability to sense and respond to intracellular copper levels, the latter manifested through their copper-regulated trafficking from the transGolgi network to the appropriate cellular membrane domain (basolateral or apical, respectively) to eliminate excess copper from the cell. Research over the last decade has yielded significant insight into the enzymatic properties and cell biology of the copper-ATPases. With recent advances in elucidating their localization and trafficking in human and animal tissues in response to physiological stimuli, we are progressing rapidly towards an integrated understanding of their physiological significance at the level of the whole animal. This knowledge in turn is helping to clarify the biochemical and cellular basis not only for the phenotypes conferred by individual Menkes and Wilson disease patient mutations, but also for the clinical variability of phenotypes associated with each of these diseases. Importantly, this information is also providing a rational basis for the applicability and appropriateness of certain diagnostic markers and therapeutic regimes. This overview will provide an update on the current state of our understanding of the localization and trafficking properties of the copper-ATPases in cells and tissues, the molecular signals and posttranslational interactions that govern their trafficking activities, and the cellular basis for the clinical phenotypes associated with disease-causing mutations.
Collapse
Affiliation(s)
- Sharon La Fontaine
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, 221 Burwood Highway, Burwood, Vic. 3125, Australia.
| | | |
Collapse
|
38
|
Abstract
PURPOSE OF REVIEW Reports of the neurologic findings in adults with acquired copper deficiency as well as the development of novel models for Menkes disease have permitted a greater understanding of the role of copper in the central nervous system. A role of mitochondrial copper homeostasis in cellular energy metabolism suggests roles for this metal in cellular differentiation and biochemical adaptation. RECENT FINDINGS Acquired copper deficiency in adults is reported with increasing frequency, often without any identifiable cause. Chemical genetic studies identified a zebrafish model of Menkes disease that can be used for high-throughput therapeutics and revealed a hierarchy of copper distribution during development. Studies in mice reveal that the copper transport protein Ctr1 is essential for intestinal copper absorption and suggest a unique role for copper in axonal extension, excitotoxic cell death and synaptic plasticity in the central nervous system. Lastly, recent biochemical studies indicate a central role for the mitochondrial matrix in cellular copper metabolism. SUMMARY The recent developments in our understanding of copper deficiency and copper homeostasis outlined in this review provide an exciting platform for future investigations intended to elucidate the role of copper in central nervous system development and disease.
Collapse
Affiliation(s)
- Erik Madsen
- Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | | |
Collapse
|
39
|
El Meskini R, Crabtree KL, Cline LB, Mains RE, Eipper BA, Ronnett GV. ATP7A (Menkes protein) functions in axonal targeting and synaptogenesis. Mol Cell Neurosci 2007; 34:409-21. [PMID: 17215139 PMCID: PMC1876716 DOI: 10.1016/j.mcn.2006.11.018] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Revised: 11/11/2006] [Accepted: 11/20/2006] [Indexed: 12/19/2022] Open
Abstract
Menkes disease (MD) is a neurodegenerative disorder caused by mutations in the copper transporter, ATP7A, a P-type ATPase. We previously used the olfactory system to demonstrate that ATP7A expression is developmentally, not constitutive, regulated, peaking during synaptogenesis when it is highly expressed in extending axons in a copper-independent manner. Although not known to be associated with axonal functions, we explored the possibility that the inability of mutant ATP7A to support axon outgrowth contributes to the neurodegeneration seen in MD. In vivo analysis of the olfactory system in mottled brindled (Atp7aMobr) mice, a rodent model for MD, demonstrates that ATP7A deficiency affects olfactory sensory neuron (OSN) maturation. Disrupted OSN axonal projections and mitral/tufted cell dendritic growth lead to altered synapse integrity and glomerular disorganization in the olfactory bulbs of Atp7aMobr mice. Our data indicate that the neuronal abnormalities observed in MD are a result of specific age-dependent developmental defects. This study demonstrates a role for ATP7A and/or copper in axon outgrowth and synaptogenesis, and will further help identify the cause of the neuropathology that characterizes MD.
Collapse
Affiliation(s)
- Rajaâ El Meskini
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030, USA.
| | | | | | | | | | | |
Collapse
|
40
|
Huster D, Lutsenko S. Wilson disease: not just a copper disorder. Analysis of a Wilson disease model demonstrates the link between copper and lipid metabolism. MOLECULAR BIOSYSTEMS 2007; 3:816-24. [DOI: 10.1039/b711118p] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
41
|
Nadjar A, Brotchie JM, Guigoni C, Li Q, Zhou SB, Wang GJ, Ravenscroft P, Georges F, Crossman AR, Bezard E. Phenotype of striatofugal medium spiny neurons in parkinsonian and dyskinetic nonhuman primates: a call for a reappraisal of the functional organization of the basal ganglia. J Neurosci 2006; 26:8653-61. [PMID: 16928853 PMCID: PMC6674386 DOI: 10.1523/jneurosci.2582-06.2006] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The classic view of anatomofunctional organization of the basal ganglia is that striatopallidal neurons of the "indirect" pathway express D2 dopamine receptors and corelease enkephalin with GABA, whereas striatopallidal neurons of the "direct" pathway bear D1 dopamine receptors and corelease dynorphin and substance P with GABA. Although many studies have investigated the pathophysiology of the basal ganglia after dopamine denervation and subsequent chronic levodopa (L-dopa) treatment, none has ever considered the possibility of plastic changes leading to profound reorganization and/or biochemical phenotype modifications of medium spiny neurons. Therefore, we studied the phenotype of striatal neurons in four groups of nonhuman primates, including the following: normal, parkinsonian, parkinsonian chronically treated with L-dopa without exhibiting dyskinesia, and parkinsonian chronically treated with L-dopa exhibiting overt dyskinesia. To identify striatal cells projecting to external (indirect) or internal (direct) segments of the globus pallidus, the retrograde tracer cholera toxin subunit B (CTb) was injected stereotaxically into the terminal areas. Using immunohistochemistry techniques, brain sections were double labeled for CTb and dopamine receptors, opioid peptides, or the substance P receptor (NK1). We also used HPLC-RIA to assess opioid levels throughout structures of the basal ganglia. Our results suggest that medium spiny neurons retain their phenotype because no variations were observed in any experimental condition. Therefore, it appears unlikely that dyskinesia is related to a phenotype modification of the striatal neurons. However, this study supports the concept of axonal collateralization of striatofugal cells that project to both globus pallidus pars externa and globus pallidus pars interna. Striatofugal pathways are not as segregated in the primate as previously considered.
Collapse
Affiliation(s)
- Agnes Nadjar
- Centre National de la Recherche Scientifique Unité Mixte de Recherche 5543 et
| | - Jonathan M. Brotchie
- School of Biological Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
- Toronto Western Research Institute, Toronto Western Hospital, Toronto, Ontario, Canada M5T 2S8, and
| | - Celine Guigoni
- Centre National de la Recherche Scientifique Unité Mixte de Recherche 5543 et
| | - Qin Li
- Laboratory Animal Research Center, China Agricultural University, Beijing 100101, China
| | - Shao-Bo Zhou
- School of Biological Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Gui-Jie Wang
- School of Biological Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Paula Ravenscroft
- School of Biological Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - François Georges
- Institut National de la Santé et de la Recherche Médicale AVENIR 01, Université Victor Segalen-Bordeaux 2, 33076 Bordeaux, France
| | - Alan R. Crossman
- School of Biological Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Erwan Bezard
- Centre National de la Recherche Scientifique Unité Mixte de Recherche 5543 et
| |
Collapse
|
42
|
Schlief ML, West T, Craig AM, Holtzman DM, Gitlin JD. Role of the Menkes copper-transporting ATPase in NMDA receptor-mediated neuronal toxicity. Proc Natl Acad Sci U S A 2006; 103:14919-24. [PMID: 17003121 PMCID: PMC1578502 DOI: 10.1073/pnas.0605390103] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Menkes disease, a fatal neurodegenerative disorder resulting in seizures, hypotonia, and failure to thrive, is due to inherited loss-of-function mutations in the gene encoding a copper-transporting ATPase (Atp7a) on the X chromosome. Although affected patients exhibit signs and symptoms of copper deficiency, the mechanisms resulting in neurologic disease remain unknown. We recently discovered that Atp7a is required for the production of an NMDA receptor-dependent releasable copper pool within hippocampal neurons, a finding that suggests a role for copper in activity-dependent modulation of synaptic activity. In support of this hypothesis, we now demonstrate that copper chelation exacerbates NMDA-mediated excitotoxic cell death in primary hippocampal neurons, whereas the addition of copper is specifically protective and results in a significant decrease in cytoplasmic Ca(2+) levels after NMDA receptor activation. Consistent with the known neuroprotective effect of NMDA receptor nitrosylation, we show here that this protective effect of copper depends on endogenous nitric oxide production in hippocampal neurons, demonstrating in vivo links among neuroprotection, copper metabolism, and nitrosylation. Atp7a is required for these copper-dependent effects: Hippocampal neurons isolated from newborn Mo(br) mice reveal a marked sensitivity to endogenous glutamate-mediated NMDA receptor-dependent excitotoxicity in vitro, and mild hypoxic/ischemic insult to these mice in vivo results in significantly increased caspase 3 activation and neuronal injury. Taken together, these data reveal a unique connection between copper homeostasis and NMDA receptor activity that is of broad relevance to the processes of synaptic plasticity and excitotoxic cell death.
Collapse
Affiliation(s)
| | | | - Ann Marie Craig
- Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110
| | | | - Jonathan D. Gitlin
- Departments of *Pediatrics
- To whom correspondence should be addressed at:
Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110. E-mail:
| |
Collapse
|
43
|
Niciu MJ, Ma XM, El Meskini R, Ronnett GV, Mains RE, Eipper BA. Developmental changes in the expression of ATP7A during a critical period in postnatal neurodevelopment. Neuroscience 2006; 139:947-64. [PMID: 16549268 DOI: 10.1016/j.neuroscience.2006.01.044] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Revised: 01/16/2006] [Accepted: 01/26/2006] [Indexed: 11/27/2022]
Abstract
ATP7A is a P-type ATPase that transports copper from cytosol into the secretory pathway for loading onto cuproproteins or efflux. Mutations in Atp7a cause Menkes disease, a copper-deficiency disorder fatal in the postnatal period due to severe neurodegeneration. Early postnatal copper injections are known to diminish degenerative changes in some human patients and mice bearing mutations in Atp7a. In situ hybridization studies previously demonstrated that ATP7A transcripts are expressed widely in the brain. ATP7A-specific antibody was used to study the neurodevelopmental expression and localization of ATP7A protein in the mouse brain. Based on immunoblot analyses, ATP7A expression is most abundant in the early postnatal period, reaching peak levels at P4 in neocortex and cerebellum. In the developing and adult brain, ATP7A levels are greatest in the choroid plexus/ependymal cells of the lateral and third ventricles. ATP7A expression decreases in most neuronal subpopulations from birth to adulthood. In contrast, ATP7A expression increases in CA2 hippocampal pyramidal and cerebellar Purkinje neurons. ATP7A is expressed in a subset of astrocytes, microglia, oligodendrocytes, tanycytes and endothelial cells. ATP7A is largely localized to the trans-Golgi network, adopting the cell-specific and developmentally-regulated morphology of this organelle. The presence of ATP7A in the axons of postnatal, but not adult, optic nerve suggests stage-specific roles for this enzyme. In sum, the precisely-regulated neurodevelopmental expression of ATP7A correlates well with the limited therapeutic window for effective treatment of Menkes disease.
Collapse
Affiliation(s)
- M J Niciu
- University of Connecticut Health Center, Department of Neuroscience, Academic Research Building (E)-4047, 263 Farmington Avenue, Farmington, CT 06030, USA
| | | | | | | | | | | |
Collapse
|