1
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Folarin OR, Olopade FE, Olopade JO. Essential Metals in the Brain and the Application of Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry for their Detection. Niger J Physiol Sci 2021; 36:123-147. [PMID: 35947740 DOI: 10.54548/njps.v36i2.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 01/05/2022] [Indexed: 06/15/2023]
Abstract
Metals are natural component of the ecosystem present throughout the layers of atmosphere; their abundant expression in the brain indicates their importance in the central nervous system (CNS). Within the brain tissue, their distribution is highly compartmentalized, the pattern of which is determined by their primary roles. Bio-imaging of the brain to reveal spatial distribution of metals within specific regions has provided a unique understanding of brain biochemistry and architecture, linking both the structures and the functions through several metal mediated activities. Bioavailability of essential trace metal is needed for normal brain function. However, disrupted metal homeostasis can influence several biochemical pathways in different fields of metabolism and cause characteristic neurological disorders with a typical disease process usually linked with aberrant metal accumulations. In this review we give a brief overview of roles of key essential metals (Iron, Copper and Zinc) including their molecular mechanisms and bio-distribution in the brain as well as their possible involvement in the pathogenesis of related neurodegenerative diseases. In addition, we also reviewed recent applications of Laser Ablation Inductively Couple Plasma Mass Spectrophotometry (LA-ICP-MS) in the detection of both toxic and essential metal dyshomeostasis in neuroscience research and other related brain diseases.
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2
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Jurcau A. Insights into the Pathogenesis of Neurodegenerative Diseases: Focus on Mitochondrial Dysfunction and Oxidative Stress. Int J Mol Sci 2021; 22:11847. [PMID: 34769277 PMCID: PMC8584731 DOI: 10.3390/ijms222111847] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 10/25/2021] [Accepted: 10/28/2021] [Indexed: 12/12/2022] Open
Abstract
As the population ages, the incidence of neurodegenerative diseases is increasing. Due to intensive research, important steps in the elucidation of pathogenetic cascades have been made and significantly implicated mitochondrial dysfunction and oxidative stress. However, the available treatment in Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis is mainly symptomatic, providing minor benefits and, at most, slowing down the progression of the disease. Although in preclinical setting, drugs targeting mitochondrial dysfunction and oxidative stress yielded encouraging results, clinical trials failed or had inconclusive results. It is likely that by the time of clinical diagnosis, the pathogenetic cascades are full-blown and significant numbers of neurons have already degenerated, making it impossible for mitochondria-targeted or antioxidant molecules to stop or reverse the process. Until further research will provide more efficient molecules, a healthy lifestyle, with plenty of dietary antioxidants and avoidance of exogenous oxidants may postpone the onset of neurodegeneration, while familial cases may benefit from genetic testing and aggressive therapy started in the preclinical stage.
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Affiliation(s)
- Anamaria Jurcau
- Department of Psycho-Neurosciences and Rehabilitation, Faculty of Medicine and Pharmacy, University of Oradea, 410073 Oradea, Romania;
- Neurology Ward, Clinical Municipal Hospital “dr. G. Curteanu” Oradea, 410154 Oradea, Romania
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3
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Maung MT, Carlson A, Olea-Flores M, Elkhadragy L, Schachtschneider KM, Navarro-Tito N, Padilla-Benavides T. The molecular and cellular basis of copper dysregulation and its relationship with human pathologies. FASEB J 2021; 35:e21810. [PMID: 34390520 DOI: 10.1096/fj.202100273rr] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 06/23/2021] [Accepted: 07/07/2021] [Indexed: 12/16/2022]
Abstract
Copper (Cu) is an essential micronutrient required for the activity of redox-active enzymes involved in critical metabolic reactions, signaling pathways, and biological functions. Transporters and chaperones control Cu ion levels and bioavailability to ensure proper subcellular and systemic Cu distribution. Intensive research has focused on understanding how mammalian cells maintain Cu homeostasis, and how molecular signals coordinate Cu acquisition and storage within organs. In humans, mutations of genes that regulate Cu homeostasis or facilitate interactions with Cu ions lead to numerous pathologic conditions. Malfunctions of the Cu+ -transporting ATPases ATP7A and ATP7B cause Menkes disease and Wilson disease, respectively. Additionally, defects in the mitochondrial and cellular distributions and homeostasis of Cu lead to severe neurodegenerative conditions, mitochondrial myopathies, and metabolic diseases. Cu has a dual nature in carcinogenesis as a promotor of tumor growth and an inducer of redox stress in cancer cells. Cu also plays role in cancer treatment as a component of drugs and a regulator of drug sensitivity and uptake. In this review, we provide an overview of the current knowledge of Cu metabolism and transport and its relation to various human pathologies.
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Affiliation(s)
- May T Maung
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT, USA
| | - Alyssa Carlson
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT, USA
| | - Monserrat Olea-Flores
- Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Guerrero, Mexico
| | - Lobna Elkhadragy
- Department of Radiology, University of Illinois at Chicago, Chicago, IL, USA
| | - Kyle M Schachtschneider
- Department of Radiology, University of Illinois at Chicago, Chicago, IL, USA.,Department of Biochemistry & Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA.,National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Napoleon Navarro-Tito
- Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Guerrero, Mexico
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4
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Obrador E, Salvador-Palmer R, López-Blanch R, Jihad-Jebbar A, Vallés SL, Estrela JM. The Link between Oxidative Stress, Redox Status, Bioenergetics and Mitochondria in the Pathophysiology of ALS. Int J Mol Sci 2021; 22:ijms22126352. [PMID: 34198557 PMCID: PMC8231819 DOI: 10.3390/ijms22126352] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 06/07/2021] [Accepted: 06/10/2021] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is the most common neurodegenerative disease of the motor system. It is characterized by the degeneration of both upper and lower motor neurons, which leads to muscle weakness and paralysis. ALS is incurable and has a bleak prognosis, with median survival of 3-5 years after the initial symptomatology. In ALS, motor neurons gradually degenerate and die. Many features of mitochondrial dysfunction are manifested in neurodegenerative diseases, including ALS. Mitochondria have shown to be an early target in ALS pathophysiology and contribute to disease progression. Disruption of their axonal transport, excessive generation of reactive oxygen species, disruption of the mitochondrial structure, dynamics, mitophagy, energy production, calcium buffering and apoptotic triggering have all been directly involved in disease pathogenesis and extensively reported in ALS patients and animal model systems. Alterations in energy production by motor neurons, which severely limit their survival capacity, are tightly linked to the redox status and mitochondria. The present review focuses on this link. Placing oxidative stress as a main pathophysiological mechanism, the molecular interactions and metabolic flows involved are analyzed. This leads to discussing potential therapeutic approaches targeting mitochondrial biology to slow disease progression.
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Affiliation(s)
- Elena Obrador
- Correspondence: (E.O.); (J.M.E.); Tel.: +34-963864646 (J.M.E.)
| | | | | | | | | | - José M. Estrela
- Correspondence: (E.O.); (J.M.E.); Tel.: +34-963864646 (J.M.E.)
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5
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Sea KW, Taylor AB, Thomas ST, Liba A, Bergman IB, Holloway SP, Cao X, Gralla EB, Valentine JS, Hart PJ, Galaleldeen A. A pH Switch Controls Zinc Binding in Tomato Copper-Zinc Superoxide Dismutase. Biochemistry 2021; 60:1597-1608. [PMID: 33961402 PMCID: PMC8754426 DOI: 10.1021/acs.biochem.1c00133] [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] [Indexed: 11/29/2022]
Abstract
Copper-zinc superoxide dismutase (SOD1) is a major antioxidant metalloenzyme that protects cells from oxidative damage by superoxide anions (O2-). Structural, biophysical, and other characteristics have in the past been compiled for mammalian SOD1s and for the highly homologous fungal and bovine SOD1s. Here, we characterize the biophysical properties of a plant SOD1 from tomato chloroplasts and present several of its crystal structures. The most unusual of these structures is a structure at low pH in which tSOD1 harbors zinc in the copper-binding site but contains no metal in the zinc-binding site. The side chain of D83, normally a zinc ligand, adopts an alternate rotameric conformation to form an unusual bidentate hydrogen bond with the side chain of D124, precluding metal binding in the zinc-binding site. This alternate conformation of D83 appears to be responsible for the previously observed pH-dependent loss of zinc from the zinc-binding site of SOD1. Titrations of cobalt into apo tSOD1 at a similar pH support the lack of an intact zinc-binding site. Further characterization of tSOD1 reveals that it is a weaker dimer relative to human SOD1 and that it can be activated in vivo through a copper chaperone for the SOD1-independent mechanism.
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Affiliation(s)
- Kevin W. Sea
- Department of Agriculture and Natural Resources, Santa Rosa Junior College, Santa Rosa, California 95401
| | - Alexander B. Taylor
- Department of Biochemistry and the X-ray Crystallography Core Laboratory, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229
| | - Susan T. Thomas
- Department of Biochemistry and the X-ray Crystallography Core Laboratory, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229
| | - Amir Liba
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095
| | - Isabelle B. Bergman
- Department of Biological Sciences, St. Mary’s University, San Antonio, TX 78228
| | - Stephen P. Holloway
- Department of Biochemistry and the X-ray Crystallography Core Laboratory, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229
| | - Xiaohang Cao
- Department of Biochemistry and the X-ray Crystallography Core Laboratory, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229
| | - Edith B. Gralla
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095
| | - Joan S. Valentine
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095
| | - P. John Hart
- Department of Biochemistry and the X-ray Crystallography Core Laboratory, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229
- Geriatric Research, Education and Clinical Center, Department of Veterans Affairs, South Texas Veterans Health Care System, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229
| | - Ahmad Galaleldeen
- Department of Biochemistry and the X-ray Crystallography Core Laboratory, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229
- Department of Biological Sciences, St. Mary’s University, San Antonio, TX 78228
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6
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Da Ros M, Deol HK, Savard A, Guo H, Meiering EM, Gibbings D. Wild-type and mutant SOD1 localizes to RNA-rich structures in cells and mice but does not bind RNA. J Neurochem 2020; 156:524-538. [PMID: 32683701 DOI: 10.1111/jnc.15126] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 06/08/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022]
Abstract
Many of the genes whose mutation causes Amyotrophic Lateral Sclerosis (ALS) are RNA-binding proteins which localize to stress granules, while others impact the assembly, stability, and elimination of stress granules. This has led to the hypothesis that alterations in the dynamics of stress granules and RNA biology cause ALS. Genetic mutations in Superoxide Dismutase 1 (SOD1) also cause ALS. Evidence demonstrates that SOD1 harboring ALS-linked mutations is recruited to stress granules, induces changes in alternative splicing, and could be an RNA-binding protein. Whether SOD1 inclusions contain RNA in disease models and whether SOD1 directly binds RNA remains uncertain. We applied methods including cross-linking immunoprecipitation and in vitro gel shift assays to detect binding of SOD1 to RNA in vitro, in cells with and without stress granules, and in mice expressing human SOD1 G93A. We find that SOD1 localizes to RNA-rich structures including stress granules, and SOD1 inclusions in mice contain mRNA. However, we find no evidence that SOD1 directly binds RNA. This suggests that SOD1 may impact stress granules, alternative splicing and RNA biology without binding directly to RNA.
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Affiliation(s)
- Matteo Da Ros
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Canada.,The Eric Poulin Centre for Neuromuscular Disease, Ottawa, ON, Canada
| | - Harmeen K Deol
- Department of Chemistry, University of Waterloo, Waterloo, ON, Canada
| | - Alexandre Savard
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Canada.,The Eric Poulin Centre for Neuromuscular Disease, Ottawa, ON, Canada
| | - Huishan Guo
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Canada.,The Eric Poulin Centre for Neuromuscular Disease, Ottawa, ON, Canada
| | | | - Derrick Gibbings
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Canada.,The Eric Poulin Centre for Neuromuscular Disease, Ottawa, ON, Canada
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7
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Ohyama T, Kuroi K, Wakabayashi T, Fujimaki N, Nakabayashi T. Enhancement of Oxidative Reaction by the Intramolecular Electron Transfer between the Coordinated Redox-Active Metal Ions in SOD1. J Phys Chem B 2020; 124:2116-2123. [PMID: 32101437 DOI: 10.1021/acs.jpcb.9b11807] [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
The denatured Cu, Zn superoxide dismutase (SOD1) has the pro-oxidant activity that is suggested to be related with the pathogenesis of amyotrophic lateral sclerosis (ALS). We showed from the changes in the coordinated metal ions that the Cu ion in the Cu-binding site is the catalytic site of the pro-oxidant activity, and a redox-active metal ion in the Zn-binding site has the auxiliary function to enhance the pro-oxidant activity. The auxiliary function is suggested to arise from the intramolecular electron transfer between the coordinated metal ions in the denatured SOD1. The oxidation/reduction cycle of Cu in the Cu-binding site is assisted with changing the oxidation state of a metal ion in the Zn-binding site. The magnitude of the toxicity of the denatured SOD1 is discussed based on the ability of the auxiliary function.
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Affiliation(s)
- Takumi Ohyama
- Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Kunisato Kuroi
- Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Taiyu Wakabayashi
- Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Nobuhiro Fujimaki
- Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Takakazu Nakabayashi
- Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
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8
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Ammendola S, Ciavardelli D, Consalvo A, Battistoni A. Cobalt can fully recover the phenotypes related to zinc deficiency in Salmonella Typhimurium. Metallomics 2020; 12:2021-2031. [PMID: 33165471 DOI: 10.1039/d0mt00145g] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Cobalt is an essential element for living systems, which, however, make very limited use of this metal, using it mainly in cobalamin-containing enzymes. The reduced use of cobalt compared to other transition metals is generally attributed to the potential toxicity of this element. In this work, we demonstrate that cobalt not only does not have an obvious toxic effect on Salmonella Typhimurium, but that it can efficiently compensate for zinc deficiency in a znuABC deleted strain. In fact, cobalt, but not cobalamin supplementation, rescued all major phenotypic defects of the znuABC strain, including the reduced ability to grow and swim in zinc-deficient media and the high susceptibility to hydrogen peroxide stress. Growth in a cobalt-supplemented defined medium led to the accumulation of large amounts of cobalt both in the wild type and in the znuABC strain. These data suggest that atoms of cobalt may be incorporated in bacterial proteins in place of zinc, ensuring their functionality. In support of this hypothesis we have shown that, in vivo, cobalt can accumulate in ribosomes and replace zinc in a periplasmic Cu,Zn superoxide dismutase (SodCII). Finally, we provide evidence of the ability of cobalt to modulate the intracellular concentration of zinc-regulated proteins (ZnuA, ZinT, and SodCII). Although some observations suggest that in some proteins the replacement of zinc with cobalt can lead to subtle structural changes, the data reported in this study indicate that Salmonella has the ability to use cobalt instead of zinc, without evident harmful effects for cell physiology.
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Affiliation(s)
- Serena Ammendola
- Department of Biology, University of Rome ''Tor Vergata'', Via della Ricerca Scientifica, 00133 Rome, Italy.
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9
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Abstract
Few proteins have come under such intense scrutiny as superoxide dismutase-1 (SOD1). For almost a century, scientists have dissected its form, function and then later its malfunction in the neurodegenerative disease amyotrophic lateral sclerosis (ALS). We now know SOD1 is a zinc and copper metalloenzyme that clears superoxide as part of our antioxidant defence and respiratory regulation systems. The possibility of reduced structural integrity was suggested by the first crystal structures of human SOD1 even before deleterious mutations in the sod1 gene were linked to the ALS. This concept evolved in the intervening years as an impressive array of biophysical studies examined the characteristics of mutant SOD1 in great detail. We now recognise how ALS-related mutations perturb the SOD1 maturation processes, reduce its ability to fold and reduce its thermal stability and half-life. Mutant SOD1 is therefore predisposed to monomerisation, non-canonical self-interactions, the formation of small misfolded oligomers and ultimately accumulation in the tell-tale insoluble inclusions found within the neurons of ALS patients. We have also seen that several post-translational modifications could push wild-type SOD1 down this toxic pathway. Recently we have come to view ALS as a prion-like disease where both the symptoms, and indeed SOD1 misfolding itself, are transmitted to neighbouring cells. This raises the possibility of intervention after the initial disease presentation. Several small-molecule and biologic-based strategies have been devised which directly target the SOD1 molecule to change the behaviour thought to be responsible for ALS. Here we provide a comprehensive review of the many biophysical advances that sculpted our view of SOD1 biology and the recent work that aims to apply this knowledge for therapeutic outcomes in ALS.
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10
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Doyle CM, Naser D, Bauman HA, Rumfeldt JA, Meiering EM. Spectrophotometric method for simultaneous measurement of zinc and copper in metalloproteins using 4-(2-pyridylazo)resorcinol. Anal Biochem 2019; 579:44-56. [DOI: 10.1016/j.ab.2019.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 03/04/2019] [Accepted: 03/17/2019] [Indexed: 12/26/2022]
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11
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Cu/Zn-superoxide dismutase and wild-type like fALS SOD1 mutants produce cytotoxic quantities of H 2O 2 via cysteine-dependent redox short-circuit. Sci Rep 2019; 9:10826. [PMID: 31346243 PMCID: PMC6658568 DOI: 10.1038/s41598-019-47326-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 07/11/2019] [Indexed: 12/13/2022] Open
Abstract
The Cu/Zn−superoxide dismutase (SOD1) is a ubiquitous enzyme that catalyzes the dismutation of superoxide radicals to oxygen and hydrogen peroxide. In addition to this principal reaction, the enzyme is known to catalyze, with various efficiencies, several redox side-reactions using alternative substrates, including biological thiols, all involving the catalytic copper in the enzyme’s active-site, which is relatively surface exposed. The accessibility and reactivity of the catalytic copper is known to increase upon SOD1 misfolding, structural alterations caused by a mutation or environmental stresses. These competing side-reactions can lead to the formation of particularly toxic ROS, which have been proposed to contribute to oxidative damage in amyotrophic lateral sclerosis (ALS), a neurodegenerative disease that affects motor neurons. Here, we demonstrated that metal-saturated SOD1WT (holo-SOD1WT) and a familial ALS (fALS) catalytically active SOD1 mutant, SOD1G93A, are capable, under defined metabolic circumstances, to generate cytotoxic quantities of H2O2 through cysteine (CSH)/glutathione (GSH) redox short-circuit. Such activity may drain GSH stores, therefore discharging cellular antioxidant potential. By analyzing the distribution of thiol compounds throughout the CNS, the location of potential hot-spots of ROS production can be deduced. These hot-spots may constitute the origin of oxidative damage to neurons in ALS.
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12
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Tiwari MK, Hägglund PM, Møller IM, Davies MJ, Bjerrum MJ. Copper ion / H 2O 2 oxidation of Cu/Zn-Superoxide dismutase: Implications for enzymatic activity and antioxidant action. Redox Biol 2019; 26:101262. [PMID: 31284117 PMCID: PMC6614508 DOI: 10.1016/j.redox.2019.101262] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/18/2019] [Accepted: 06/26/2019] [Indexed: 01/25/2023] Open
Abstract
Copper ion-catalyzed oxidation of yeast SOD1 (ySOD1) was examined to determine early oxidative modifications, including oxidation of a crucial disulfide bond, and the structural and functional repercussions of these events. The study used distinct oxidative conditions: Cu2+/H2O2, Cu2+/H2O2/AscH− and Cu2+/H2O2/glucose. Capillary electrophoresis experiments and quantification of protein carbonyls indicate that ySOD1 is highly susceptible to oxidative modification and that changes can be detected within 0.1 min of the initiation of the reaction. Oxidation-induced structural perturbations, characterized by circular dichroism, revealed the formation of partially-unfolded ySOD1 species in a dose-dependent manner. Consistent with these structural changes, pyrogallol assay indicates a partial loss of enzymatic activity. ESI-MS analyses showed seven distinct oxidized ySOD1 species under mild oxidation within 0.1 min. LC/MS analysis after proteolytic digestion demonstrated that the copper-coordinating active site histidine residues, His47 and His49, were converted into 2-oxo-histidine. Furthermore, the Cu and Zn bridging residue, His64 is converted into aspartate/asparagine. Importantly, the disulfide-bond Cys58-Cys147 which is critical for the structural and functional integrity of ySOD1 was detected as being oxidized at Cys147. We propose, based on LC/MS analyses, that disulfide-bond oxidation occurs without disulfide bond cleavage. Modifications were also detected at Met85 and five surface-exposed Lys residues. Based on these data we propose that the Cys58-Cys147 bond may act as a sacrificial target for oxidants and protect ySOD1 from oxidative inactivation arising from exposure to Cu2+/H2O2 and auto-inactivation during extended enzymatic turnover. Oxidation of yeast superoxide dismutase (ySOD1) by Cu2+/H2O2 is examined. Rapid modification of His, Met, Cys and Lys residues detected by LC-MS methods. Oxidation of active site His residues and partial protein unfolding are early events. The Cys58-Cys147 disulfide bond is oxidized and may act as a sacrificial target. Excess exogenous Cu2+ decreases protein damage and can reverse loss of activity.
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Affiliation(s)
- Manish K Tiwari
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Per M Hägglund
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ian Max Møller
- Department of Molecular Biology and Genetics, Aarhus University, Slagelse, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten J Bjerrum
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark.
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13
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Hilton JB, Kysenius K, White AR, Crouch PJ. The accumulation of enzymatically inactive cuproenzymes is a CNS-specific phenomenon of the SOD1 G37R mouse model of ALS and can be restored by overexpressing the human copper transporter hCTR1. Exp Neurol 2018; 307:118-128. [PMID: 29906423 DOI: 10.1016/j.expneurol.2018.06.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 05/28/2018] [Accepted: 06/11/2018] [Indexed: 12/13/2022]
Abstract
Mutations to the copper-dependent enzyme Cu/Zn-superoxide dismutase (SOD1) cause amyotrophic lateral sclerosis (ALS) in humans, and transgenic overexpression of mutant SOD1 represents a robust murine model of the disease. We have previously shown that the copper-containing compound CuII(atsm) phenotypically improves mutant SOD1 mice and delivers copper to copper-deficient SOD1 in the CNS to restore its physiological function. CuII(atsm) is now in clinical trials for the treatment of ALS. In this study, we demonstrate that cuproenzyme dysfunction extends beyond SOD1 in SOD1G37R mice to also affect the endogenous copper-dependent ferroxidase ceruloplasmin. We show that SOD1 and ceruloplasmin both accumulate progressively in the SOD1G37R mouse spinal cord as the animals' ALS-like symptoms progress, yet the biochemical activity of the two cuproenzymes does not increase commensurately, indicating that, as per mutant SOD1, ceruloplasmin accumulates in a copper-deficient form. Consistent with this finding, we show that expression of the human copper transporter 1 (hCTR1) in SOD1G37R mice increases copper levels in the spinal cord and concurrently restores SOD1 and ceruloplasmin activity. Soluble misfolded SOD1, a proposed driver of pathology in this model, is readily detectable in the SOD1G37R mouse spinal cord. However, misfolded SOD1G37R levels do not change in abundance with disease progression and are less abundant than misfolded SOD1 in the spinal cords of age-matched transgenic SOD1WT mice which do not exhibit an evident ALS-like phenotype. Collectively, these outcomes support a copper malfunction phenomenon in mutant SOD1 mouse models of ALS and a copper-related mechanism of action for the therapeutic agent CuII(atsm).
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Affiliation(s)
- James B Hilton
- Department of Pharmacology and Therapeutics, the University of Melbourne, Victoria 3010, Australia.
| | - Kai Kysenius
- Department of Pharmacology and Therapeutics, the University of Melbourne, Victoria 3010, Australia; Florey Institute of Neuroscience and Mental Health, the University of Melbourne, Victoria 3010, Australia
| | - Anthony R White
- Cell and Molecular Biology, QIMR Berghofer Medical Research Institute, Queensland 4006, Australia
| | - Peter J Crouch
- Department of Pharmacology and Therapeutics, the University of Melbourne, Victoria 3010, Australia; Florey Institute of Neuroscience and Mental Health, the University of Melbourne, Victoria 3010, Australia
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14
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Tachu BJ, Wüsten KA, Garza MC, Wille H, Tamgüney G. An easy method for bacterial expression and purification of wild-type and mutant superoxide dismutase 1 (SOD1). Protein Expr Purif 2017; 134:63-71. [DOI: 10.1016/j.pep.2017.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 02/06/2017] [Accepted: 04/01/2017] [Indexed: 12/13/2022]
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15
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Imaging of glial cell morphology, SOD1 distribution and elemental composition in the brainstem and hippocampus of the ALS hSOD1 G93A rat. Neuroscience 2017; 357:37-55. [PMID: 28576725 DOI: 10.1016/j.neuroscience.2017.05.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 05/23/2017] [Accepted: 05/23/2017] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder affecting motor and cognitive domains of the CNS. Mutations in the Cu,Zn-superoxide dismutase (SOD1) cause 20% of familial ALS and provoke formation of intracellular aggregates and copper and zinc unbinding, leading to glial activation and neurodegeneration. Therefore, we investigated glial cell morphology, intracellular SOD1 distribution, and elemental composition in the brainstem and hippocampus of the hSOD1G93A transgenic rat model of ALS. Immunostaining for astrocytes, microglia and SOD1 revealed glial proliferation and progressive tissue accumulation of SOD1 in both brain regions of ALS rats starting already at the presymptomatic stage. Glial cell morphology analysis in the brainstem of ALS rats revealed astrocyte activation occurring before disease symptoms onset, followed by activation of microglia. Hippocampal ALS astrocytes exhibited an identical reactive profile, while microglial morphology was unchanged. Additionally, ALS brainstem astrocytes demonstrated progressive SOD1 accumulation in the cell body and processes, while microglial SOD1 levels were reduced and its distribution limited to distal cell processes. In the hippocampus both glial cell types exhibited SOD1 accumulation in the cell body. X-ray fluorescence imaging revealed decreased P and increased Ca, Cl, K, Ni, Cu and Zn in the brainstem, and higher levels of Cl, Ni and Cu, but lower levels of Zn in the hippocampus of symptomatic ALS rats. These results bring new insights into the glial response during disease development and progression in motor as well as in non-motor CNS structures, and indicate disturbed tissue elemental homeostasis as a prominent hallmark of disease pathology.
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Wright GSA, Antonyuk SV, Hasnain SS. A faulty interaction between SOD1 and hCCS in neurodegenerative disease. Sci Rep 2016; 6:27691. [PMID: 27282955 PMCID: PMC4901319 DOI: 10.1038/srep27691] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 05/19/2016] [Indexed: 01/12/2023] Open
Abstract
A proportion of Amyotrophic lateral sclerosis (ALS) cases result from impaired mutant superoxide dismutase-1 (SOD1) maturation. The copper chaperone for SOD1 (hCCS) forms a transient complex with SOD1 and catalyses the final stages of its maturation. We find that a neurodegenerative disease-associated hCCS mutation abrogates the interaction with SOD1 by inhibiting hCCS zinc binding. Analogously, SOD1 zinc loss has a detrimental effect on the formation, structure and disassociation of the hCCS-SOD1 heterodimer. This suggests that hCCS functionality is impaired by ALS mutations that reduce SOD1 zinc affinity. Furthermore, stabilization of wild-type SOD1 by chemical modification including cisplatination, inhibits complex formation. We hypothesize that drug molecules designed to stabilize ALS SOD1 mutants that also target the wild-type form will lead to characteristics common in SOD1 knock-outs. Our work demonstrates the applicability of chromatographic SAXS when studying biomolecules predisposed to aggregation or dissociation; attributes frequently reported for complexes involved in neurodegenerative disease.
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Affiliation(s)
- Gareth S. A. Wright
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, UK
| | - Svetlana V. Antonyuk
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, UK
| | - S. Samar Hasnain
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, UK
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17
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Broom HR, Vassall KA, Rumfeldt JAO, Doyle CM, Tong MS, Bonner JM, Meiering EM. Combined Isothermal Titration and Differential Scanning Calorimetry Define Three-State Thermodynamics of fALS-Associated Mutant Apo SOD1 Dimers and an Increased Population of Folded Monomer. Biochemistry 2016; 55:519-33. [PMID: 26710831 DOI: 10.1021/acs.biochem.5b01187] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Many proteins are naturally homooligomers, homodimers most frequently. The overall stability of oligomeric proteins may be described in terms of the stability of the constituent monomers and the stability of their association; together, these stabilities determine the populations of different monomer and associated species, which generally have different roles in the function or dysfunction of the protein. Here we show how a new combined calorimetry approach, using isothermal titration calorimetry to define monomer association energetics together with differential scanning calorimetry to measure total energetics of oligomer unfolding, can be used to analyze homodimeric unmetalated (apo) superoxide dismutase (SOD1) and determine the effects on the stability of structurally diverse mutations associated with amyotrophic lateral sclerosis (ALS). Despite being located throughout the protein, all mutations studied weaken the dimer interface, while concomitantly either decreasing or increasing the marginal stability of the monomer. Analysis of the populations of dimer, monomer, and unfolded monomer under physiological conditions of temperature, pH, and protein concentration shows that all mutations promote the formation of folded monomers. These findings may help rationalize the key roles proposed for monomer forms of SOD1 in neurotoxic aggregation in ALS, as well as roles for other forms of SOD1. Thus, the results obtained here provide a valuable approach for the quantitative analysis of homooligomeric protein stabilities, which can be used to elucidate the natural and aberrant roles of different forms of these proteins and to improve methods for predicting protein stabilities.
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Affiliation(s)
- Helen R Broom
- Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Kenrick A Vassall
- Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Jessica A O Rumfeldt
- Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Colleen M Doyle
- Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Ming Sze Tong
- Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Julia M Bonner
- Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Elizabeth M Meiering
- Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
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Tsubota A, Ichijo H, Homma K. Mislocalization, aggregation formation and defect in proteolysis in ALS. AIMS MOLECULAR SCIENCE 2016. [DOI: 10.3934/molsci.2016.2.246] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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19
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Fujimaki N, Miura T, Nakabayashi T. The structural analysis of the pro-oxidant copper-binding site of denatured apo-H43R SOD1 and the elucidation of the origin of the acquisition of the pro-oxidant activity. Phys Chem Chem Phys 2016; 18:4468-75. [DOI: 10.1039/c5cp07729j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The structure of the Cu2+-binding site of denatured apo-SOD1 mutant (H43R) was investigated to clarify the mechanism of the acquisition of the pro-oxidant activity.
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Affiliation(s)
- Nobuhiro Fujimaki
- Graduate School of Pharmaceutical Sciences
- Tohoku University
- Sendai 980-8578
- Japan
| | - Takashi Miura
- Graduate School of Pharmaceutical Sciences
- Tohoku University
- Sendai 980-8578
- Japan
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20
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Chattopadhyay M, Nwadibia E, Strong CD, Gralla EB, Valentine JS, Whitelegge JP. The Disulfide Bond, but Not Zinc or Dimerization, Controls Initiation and Seeded Growth in Amyotrophic Lateral Sclerosis-linked Cu,Zn Superoxide Dismutase (SOD1) Fibrillation. J Biol Chem 2015; 290:30624-36. [PMID: 26511321 DOI: 10.1074/jbc.m115.666503] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Indexed: 12/22/2022] Open
Abstract
Aggregation of copper-zinc superoxide dismutase (SOD1) is a defining feature of familial ALS caused by inherited mutations in the sod1 gene, and misfolded and aggregated forms of wild-type SOD1 are found in both sporadic and familial ALS cases. Mature SOD1 owes its exceptional stability to a number of post-translational modifications as follows: formation of the intramolecular disulfide bond, binding of copper and zinc, and dimerization. Loss of stability due to the failure to acquire one or more of these modifications is proposed to lead to aggregation in vivo. Previously, we showed that the presence of apo-, disulfide-reduced SOD1, the most immature form of SOD1, results in initiation of fibrillation of more mature forms that have an intact Cys-57-Cys-146 disulfide bond and are partially metallated. In this study, we examine the ability of each of the above post-translational modifications to modulate fibril initiation and seeded growth. Cobalt or zinc binding, despite conferring great structural stability, neither inhibits the initiation propensity of disulfide-reduced SOD1 nor consistently protects disulfide-oxidized SOD1 from being recruited into growing fibrils across wild-type and a number of ALS mutants. In contrast, reduction of the disulfide bond, known to be necessary for fibril initiation, also allows for faster recruitment during seeded amyloid growth. These results identify separate factors that differently influence seeded growth and initiation and indicate a lack of correlation between the overall thermodynamic stability of partially mature SOD1 states and their ability to initiate fibrillation or be recruited by a growing fibril.
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Affiliation(s)
- Madhuri Chattopadhyay
- From the Department of Chemistry and Biochemistry UCLA, Los Angeles, California 90095,
| | - Ekeoma Nwadibia
- From the Department of Chemistry and Biochemistry UCLA, Los Angeles, California 90095
| | - Cynthia D Strong
- the Department of Chemistry, Cornell College, Mt. Vernon, Iowa 52314, and
| | - Edith Butler Gralla
- From the Department of Chemistry and Biochemistry UCLA, Los Angeles, California 90095
| | | | - Julian P Whitelegge
- From the Department of Chemistry and Biochemistry UCLA, Los Angeles, California 90095, the The Pasarow Mass Spectrometry Laboratory, NPI-Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
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21
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Deal CE, Balazs AB. Engineering humoral immunity as prophylaxis or therapy. Curr Opin Immunol 2015; 35:113-22. [PMID: 26183209 DOI: 10.1016/j.coi.2015.06.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 06/24/2015] [Indexed: 01/01/2023]
Abstract
PURPOSE OF THE REVIEW In this review, we will discuss the field of engineered humoral immunity with an emphasis on recent work using viral vectors to produce antibodies in vivo. As an alternative to passive transfer of monoclonal antibody protein, a transgene encoding an antibody is delivered to cells via vector transduction, resulting in expression and secretion by the host cell. This review will summarize the evidence in support of this strategy as an alternative to traditional vaccines against infection and as novel therapeutics for a variety of diseases. RECENT FINDINGS Historically, humoral immunity has been engineered through vaccination and passive transfer of monoclonal antibodies. However, recent work suggests that vectors can be used to deliver transgenes encoding broadly neutralizing antibodies to non-hematopoietic tissues and can mediate long-term expression that is capable of preventing or treating infectious diseases. The production of engineered monoclonal antibodies allows for precise targeting and elimination of aberrant self-proteins that are characteristic of certain neurodegenerative disease. This approach has also been successfully used to combat cancer and addiction in several animal models. Despite the wide array of expression platforms that have been described, adeno-associated virus vectors have emerged as the frontrunner for rapid clinical translation. SUMMARY Recent advances in vector-mediated antibody expression have demonstrated the potential for such interventions to prevent infection and treat disease. As such, it offers an alternative to immunogen-based vaccine design and a novel therapeutic intervention by enabling precise manipulation of humoral immunity. Success translating these approaches to patients may enable the development of effective prevention against previously intractable pathogens that evade immunity such as HIV, influenza, malaria or HCV and may also enable new treatment options for neurodegenerative diseases such as Alzheimer's disease.
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Affiliation(s)
- Cailin E Deal
- Ragon Institute of MGH, MIT & Harvard, 400 Technology Sq., Cambridge, MA 02139, United States
| | - Alejandro B Balazs
- Ragon Institute of MGH, MIT & Harvard, 400 Technology Sq., Cambridge, MA 02139, United States.
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22
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Nechay MR, Valdez CE, Alexandrova AN. Computational Treatment of Metalloproteins. J Phys Chem B 2015; 119:5945-56. [DOI: 10.1021/acs.jpcb.5b00028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Michael R. Nechay
- Department
of Chemistry and Biochemistry and ‡California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Crystal E. Valdez
- Department
of Chemistry and Biochemistry and ‡California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Anastassia N. Alexandrova
- Department
of Chemistry and Biochemistry and ‡California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
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23
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Hilton JB, White AR, Crouch PJ. Metal-deficient SOD1 in amyotrophic lateral sclerosis. J Mol Med (Berl) 2015; 93:481-7. [PMID: 25754173 PMCID: PMC4408375 DOI: 10.1007/s00109-015-1273-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/24/2015] [Accepted: 02/25/2015] [Indexed: 12/13/2022]
Abstract
Mutations to the ubiquitous antioxidant enzyme Cu/Zn superoxide dismutase (SOD1) were the first established genetic cause of the fatal, adult-onset neurodegenerative disease amyotrophic lateral sclerosis (ALS). It is widely accepted that these mutations do not cause ALS via a loss of antioxidant function, but elucidating the alternate toxic gain of function has proven to be elusive. Under physiological conditions, SOD1 binds one copper ion and one zinc ion per monomer to form a highly stable and functional homodimer, but there is now ample evidence to indicate aberrant persistence of SOD1 in an intermediate metal-deficient state may contribute to the protein’s involvement in ALS. This review briefly discusses some of the data to support a role for metal-deficient SOD1 in the development of ALS and some of the outcomes from drug development studies that have aimed to modify the symptoms of ALS by targeting the metal state of SOD1. The implications for the metal state of SOD1 in cases of sporadic ALS that do not involve mutant SOD1 are also discussed.
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Affiliation(s)
- James B Hilton
- Department of Pathology, The University of Melbourne, Melbourne, Victoria, 3010, Australia
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24
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Casci I, Pandey UB. A fruitful endeavor: modeling ALS in the fruit fly. Brain Res 2014; 1607:47-74. [PMID: 25289585 DOI: 10.1016/j.brainres.2014.09.064] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 09/26/2014] [Accepted: 09/27/2014] [Indexed: 12/11/2022]
Abstract
For over a century Drosophila melanogaster, commonly known as the fruit fly, has been instrumental in genetics research and disease modeling. In more recent years, it has been a powerful tool for modeling and studying neurodegenerative diseases, including the devastating and fatal amyotrophic lateral sclerosis (ALS). The success of this model organism in ALS research comes from the availability of tools to manipulate gene/protein expression in a number of desired cell-types, and the subsequent recapitulation of cellular and molecular phenotypic features of the disease. Several Drosophila models have now been developed for studying the roles of ALS-associated genes in disease pathogenesis that allowed us to understand the molecular pathways that lead to motor neuron degeneration in ALS patients. Our primary goal in this review is to highlight the lessons we have learned using Drosophila models pertaining to ALS research. This article is part of a Special Issue entitled ALS complex pathogenesis.
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Affiliation(s)
- Ian Casci
- Department of Pediatrics, Child Neurology and Neurobiology, Children׳s Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA; Human Genetics Graduate Program, University of Pittsburgh School of Public Health, Pittsburgh, PA 15261, USA
| | - Udai Bhan Pandey
- Department of Pediatrics, Child Neurology and Neurobiology, Children׳s Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA.
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25
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Cu,Zn-superoxide dismutase without Zn is folded but catalytically inactive. J Mol Biol 2014; 426:4112-4124. [PMID: 25083917 DOI: 10.1016/j.jmb.2014.07.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 07/05/2014] [Accepted: 07/20/2014] [Indexed: 02/04/2023]
Abstract
Amyotrophic lateral sclerosis has been linked to the gain of aberrant function of superoxide dismutase, Cu,Zn-SOD1 upon protein misfolding. The mechanism of SOD1 misfolding is thought to involve mutations leading to the loss of Zn, followed by protein unfolding and aggregation. We show that the removal of Zn from SOD1 may not lead to an immediate unfolding but immediately deactivates the enzyme through a combination of subtle structural and electronic effects. Using quantum mechanics/discrete molecular dynamics, we showed that both Zn-less wild-type (WT)-SOD1 and its D124N mutant that does not bind Zn have at least metastable folded states. In those states, the reduction potential of Cu increases, leading to the presence of detectable amounts of Cu(I) instead of Cu(II) in the active site, as confirmed experimentally. The Cu(I) protein cannot participate in the catalytic Cu(I)-Cu(II) cycle. However, even without the full reduction to Cu(I), the Cu site in the Zn-less variants of SOD1 is shown to be catalytically incompetent: unable to bind superoxide in a way comparable to the WT-SOD1. The changes are more radical and different in the D124N Zn-less mutant than in the Zn-less WT-SOD1, suggesting D124N being perhaps not the most adequate model for Zn-less SOD1. Overall, Zn in SOD1 appears to be influencing the Cu site directly by adjusting its reduction potential and geometry. Thus, the role of Zn in SOD1 is not just structural, as was previously thought; it is a vital part of the catalytic machinery.
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26
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Ming LJ, Valentine JS. Insights into SOD1-linked amyotrophic lateral sclerosis from NMR studies of Ni(2+)- and other metal-ion-substituted wild-type copper-zinc superoxide dismutases. J Biol Inorg Chem 2014; 19:647-57. [PMID: 24692094 PMCID: PMC4109160 DOI: 10.1007/s00775-014-1126-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 03/12/2014] [Indexed: 12/14/2022]
Abstract
The dimeric Cu-Zn superoxide dismutase (SOD1) is a particularly interesting system for biological inorganic chemical studies because substitutions of the native Cu and/or Zn ions by a nonnative metal ion cause minimal structural changes and result in high enzymatic activity for those derivatives with Cu remaining in the Cu site. The pioneering NMR studies of the magnetically coupled derivative Cu2Co2SOD1 by Ivano Bertini and coworkers are of particular importance in this regard. In addition to Co(2+), Ni(2+) is a versatile metal ion for substitution into SOD1, showing very little disturbance of the structure in Cu2Ni2SOD1 and acting as a very good mimic of the native Cu ion in Ni2Zn2SOD1. The NMR studies presented here were inspired by and are indebted to Ivano Bertini's paramagnetic NMR pursuits of metalloproteins. We report Ni(2+) binding to apo wild-type SOD1 and a time-dependent Ni(2+) migration from the Zn site to the Cu site, and the preparation and characterization of Ni2Ni2SOD1, which shows coordination properties similar to those of Cu2Cu2SOD1, namely, an anion-binding property different from that of the wild type and a possibly broken bridging His. Mutations in the human SOD1 gene can cause familial amyotrophic lateral sclerosis (ALS), and mutant SOD1 proteins with significantly altered metal-binding behaviors are implicated in causing the disease. We conclude by discussing the effects of the ALS mutations on the remarkable stabilities and metal-binding properties of wild-type SOD1 proteins and the implications concerning the causes of SOD1-linked ALS.
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Affiliation(s)
- Li-June Ming
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, Tampa, FL 33620-5250, USA
| | - Joan Selverstone Valentine
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA 90095-1569, USA
- Department of Bioinspired Science, Ewha Womans University, 120-750, Seoul, Republic of Korea
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Hitchler MJ, Domann FE. Regulation of CuZnSOD and its redox signaling potential: implications for amyotrophic lateral sclerosis. Antioxid Redox Signal 2014; 20:1590-8. [PMID: 23795822 PMCID: PMC3960847 DOI: 10.1089/ars.2013.5385] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
SIGNIFICANCE Molecular oxygen is a Janus-faced electron acceptor for biological systems, serving as a reductant for respiration, or as the genesis for oxygen-derived free radicals that damage macromolecules. Superoxide is well known to perturb nonheme iron proteins, including Fe/S proteins such as aconitase and succinate dehydrogenase, as well as other enzymes containing labile iron such as the prolyl hydroxylase domain-containing family of enzymes; whereas hydrogen peroxide is more specific for two-electron reactions with thiols on glutathione, glutaredoxin, thioredoxin, and the peroxiredoxins. RECENT ADVANCES Over the past two decades, familial cases of amyotrophic lateral sclerosis (ALS) have been shown to have an association with commonly altered superoxide dismutase 1 (SOD1) activity, expression, and protein structure. This has led to speculation that an altered redox balance may have a role in creating the ALS phenotype. CRITICAL ISSUES While SOD1 alterations in familial ALS are manifold, they generally create perturbations in the flux of electrons. The nexus of SOD1 between one- and two-electron signaling processes places it at a key signaling regulatory checkpoint for governing cellular responses to physiological and environmental cues. FUTURE DIRECTIONS The manner in which ALS-associated mutations adjust SOD1's role in controlling the flow of electrons between one- and two-electron signaling processes remains obscure. Here, we discuss the ways in which SOD1 mutations influence the form and function of copper zinc SOD, the consequences of these alterations on free radical biology, and how these alterations might influence cell signaling during the onset of ALS.
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Affiliation(s)
- Michael J Hitchler
- 1 Department of Radiation Oncology, Kaiser Permanente Los Angeles Medical Center , Los Angeles, California
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28
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Keerthana S, Kolandaivel P. Study of mutation and misfolding of Cu-Zn SOD1 protein. J Biomol Struct Dyn 2013; 33:167-83. [DOI: 10.1080/07391102.2013.865104] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Gao XM, Jia FX, Shen GM, Jiang HQ, Dou W, Wang JJ. Involvement of superoxide dismutase in oxidative stress in the oriental fruit fly, Bactrocera dorsalis: molecular cloning and expression profiles. PEST MANAGEMENT SCIENCE 2013; 69:1315-1325. [PMID: 23529838 DOI: 10.1002/ps.3503] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2012] [Revised: 12/12/2012] [Accepted: 02/05/2013] [Indexed: 06/02/2023]
Abstract
BACKGROUND Bactrocera dorsalis, one of the most economically important fruit fly pests in East Asia, is well adapted to various environmental conditions. Pesticides, pathogens and other stresses can cause oxidative damage in most organisms. The superoxide dismutase (SOD) family contains some of the most important enzymes in the antioxidant protection system of the fruit fly and other organisms. RESULTS Four full-length cDNA sequences encoding one MnSOD (BdSOD2-1) and three Cu-ZnSODs (BdSOD1-1, BdSOD1-2 and BdSOD1-3) were cloned. The expression profiles of these four genes under different stresses showed them to be involved in response to detrimental conditions including heavy metals, pesticides, extreme temperatures and lipopolysaccharide (LPS) stresses. More specifically, the expression levels of these genes were found to be depressed in the presence of copper, zinc and manganese. The expression of all four SOD genes increased upon exposure to lead, cadmium, low temperature (0 °C) and LPS stresses. Only BdSOD1-3 transcription increased significantly at high temperature (40 °C) exposure. The expressions levels of BdSOD1-2 and BdSOD1-3 increased significantly in the presence of β-cypermethrin and malathion, but only the expression of BdSOD2-1 increased in the presence of avermectin treatment. CONCLUSION These different expression profiles suggest that the four BdSODs play different roles and respond to different oxidative stresses in B. dorsalis. Some BdSODs undergo specific reaction in the response to specific oxidative stresses.
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Affiliation(s)
- Xue-Meng Gao
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, PR China
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Bahadorani S, Mukai ST, Rabie J, Beckman JS, Phillips JP, Hilliker AJ. Expression of zinc-deficient human superoxide dismutase in Drosophila neurons produces a locomotor defect linked to mitochondrial dysfunction. Neurobiol Aging 2013; 34:2322-30. [PMID: 23601674 DOI: 10.1016/j.neurobiolaging.2013.03.024] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Revised: 03/03/2013] [Accepted: 03/18/2013] [Indexed: 10/27/2022]
Abstract
More than 130 different mutations in the Cu/Zn superoxide dismutase (SOD1) gene have been associated with amyotrophic lateral sclerosis but the mechanism of this toxicity remains controversial. To gain insight into the importance of the zinc site in the pathogenesis of SOD1 in vivo, we generated a Drosophila model with transgenic expression of a zinc-deficient human SOD1. Expression of zinc-deficient SOD1 in Drosophila resulted in a progressive movement defect with associated mitochondrial cristae vacuolization and reductions in adenosine triphosphate (ATP) levels. Furthermore, these flies are sensitized to mitochondrial toxins, paraquat, and zinc. Importantly, we show that the zinc-deficient SOD1-induced motor defect can be ameliorated by supplementing the endogenous fly respiratory chain machinery with the single-subunit NADH-ubiquinone oxidoreductase from yeast (NADH is nicotinamide adenine dinucleotide, reduced form.). These results demonstrate that zinc-deficient SOD1 is neurotoxic in vivo and suggest that mitochondrial dysfunction plays a critical role in this toxicity. The robust behavioral, pathological, and biochemical phenotypes conferred by zinc-deficient SOD1 in Drosophila have general implications for the role of the zinc ion in familial and sporadic amyotrophic lateral sclerosis.
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Affiliation(s)
- Sepehr Bahadorani
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, USA
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Pastsart U, De Boever M, Claeys E, De Smet S. Effect of muscle and post-mortem rate of pH and temperature fall on antioxidant enzyme activities in beef. Meat Sci 2012; 93:681-6. [PMID: 23273481 DOI: 10.1016/j.meatsci.2012.11.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 10/03/2012] [Accepted: 11/10/2012] [Indexed: 10/27/2022]
Abstract
The aim of this study was to investigate the effect of muscle, inner and outer Musculus biceps femoris (IBF and OBF respectively) and Musculus longissimus dorsi (LD), on the post-mortem rate of pH and temperature fall, and the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) during simulated retail display. At day 0 of display (2 days post-mortem), the CAT and GSH-Px activities were lower in IBF than in OBF and LD (P<0.001), and the SOD activity was lower in OBF compared to IBF and LD (P<0.001). At day 10 of display, SOD and CAT activities had decreased in all three muscles compared to day 0 (P<0.001), whereas the GSH-Px activity did increase with time of display. Across muscles, there were significant relationships between temperature fall, colour, lipid and colour stability and antioxidant enzyme activities.
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Affiliation(s)
- Umaporn Pastsart
- Laboratory for Animal Nutrition and Animal Product Quality, Department of Animal Production, Faculty of Bioscience Engineering, Ghent University, Proefhoevestraat 10, 9090 Melle, Belgium
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Redox properties of the disulfide bond of human Cu,Zn superoxide dismutase and the effects of human glutaredoxin 1. Biochem J 2012; 446:59-67. [PMID: 22651090 DOI: 10.1042/bj20120075] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The intramolecular disulfide bond in hSOD1 [human SOD1 (Cu,Zn superoxide dismutase 1)] plays a key role in maintaining the protein's stability and quaternary structure. In mutant forms of SOD1 that cause familial ALS (amyotrophic lateral sclerosis), this disulfide bond is more susceptible to chemical reduction, which may lead to destabilization of the dimer and aggregation. During hSOD1 maturation, disulfide formation is catalysed by CCS1 (copper chaperone for SOD1). Previous studies in yeast demonstrate that the yeast GSH/Grx (glutaredoxin) redox system promotes reduction of the hSOD1 disulfide in the absence of CCS1. In the present study, we probe further the interaction between hSOD1, GSH and Grxs to provide mechanistic insight into the redox kinetics and thermodynamics of the hSOD1 disulfide. We demonstrate that hGrx1 (human Grx1) uses a monothiol mechanism to reduce the hSOD1 disulfide, and the GSH/hGrx1 system reduces ALS mutant SOD1 at a faster rate than WT (wild-type) hSOD1. However, redox potential measurements demonstrate that the thermodynamic stability of the disulfide is not consistently lower in ALS mutants compared with WT hSOD1. Furthermore, the presence of metal cofactors does not influence the disulfide redox potential. Overall, these studies suggest that differences in the GSH/hGrx1 reaction rate with WT compared with ALS mutant hSOD1 and not the inherent thermodynamic stability of the hSOD1 disulfide bond may contribute to the greater pathogenicity of ALS mutant hSOD1.
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Tiwari MK, Singh RK, Singh R, Jeya M, Zhao H, Lee JK. Role of conserved glycine in zinc-dependent medium chain dehydrogenase/reductase superfamily. J Biol Chem 2012; 287:19429-39. [PMID: 22500022 DOI: 10.1074/jbc.m111.335752] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The medium-chain dehydrogenase/reductase (MDR) superfamily consists of a large group of enzymes with a broad range of activities. Members of this superfamily are currently the subject of intensive investigation, but many aspects, including the zinc dependence of MDR superfamily proteins, have not yet have been adequately investigated. Using a density functional theory-based screening strategy, we have identified a strictly conserved glycine residue (Gly) in the zinc-dependent MDR superfamily. To elucidate the role of this conserved Gly in MDR, we carried out a comprehensive structural, functional, and computational analysis of four MDR enzymes through a series of studies including site-directed mutagenesis, isothermal titration calorimetry, electron paramagnetic resonance (EPR), quantum mechanics, and molecular mechanics analysis. Gly substitution by other amino acids posed a significant threat to the metal binding affinity and activity of MDR superfamily enzymes. Mutagenesis at the conserved Gly resulted in alterations in the coordination of the catalytic zinc ion, with concomitant changes in metal-ligand bond length, bond angle, and the affinity (K(d)) toward the zinc ion. The Gly mutants also showed different spectroscopic properties in EPR compared with those of the wild type, indicating that the binding geometries of the zinc to the zinc binding ligands were changed by the mutation. The present results demonstrate that the conserved Gly in the GHE motif plays a role in maintaining the metal binding affinity and the electronic state of the catalytic zinc ion during catalysis of the MDR superfamily enzymes.
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Gould TW, Oppenheim RW. Motor neuron trophic factors: therapeutic use in ALS? BRAIN RESEARCH REVIEWS 2011; 67:1-39. [PMID: 20971133 PMCID: PMC3109102 DOI: 10.1016/j.brainresrev.2010.10.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2010] [Revised: 10/12/2010] [Accepted: 10/18/2010] [Indexed: 12/12/2022]
Abstract
The modest effects of neurotrophic factor (NTF) treatment on lifespan in both animal models and clinical studies of Amyotropic Lateral Sclerosis (ALS) may result from any one or combination of the four following explanations: 1.) NTFs block cell death in some physiological contexts but not in ALS; 2.) NTFs do not rescue motoneurons (MNs) from death in any physiological context; 3.) NTFs block cell death in ALS but to no avail; and 4.) NTFs are physiologically effective but limited by pharmacokinetic constraints. The object of this review is to critically evaluate the role of both NTFs and the intracellular cell death pathway itself in regulating the survival of spinal and cranial (lower) MNs during development, after injury and in response to disease. Because the role of molecules mediating MN survival has been most clearly resolved by the in vivo analysis of genetically engineered mice, this review will focus on studies of such mice expressing reporter, null or other mutant alleles of NTFs, NTF receptors, cell death or ALS-associated genes.
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Affiliation(s)
- Thomas W Gould
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1010, USA.
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35
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Sahawneh MA, Ricart KC, Roberts BR, Bomben VC, Basso M, Ye Y, Sahawneh J, Franco MC, Beckman JS, Estévez AG. Cu,Zn-superoxide dismutase increases toxicity of mutant and zinc-deficient superoxide dismutase by enhancing protein stability. J Biol Chem 2010; 285:33885-97. [PMID: 20663894 PMCID: PMC2962488 DOI: 10.1074/jbc.m110.118901] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
When replete with zinc and copper, amyotrophic lateral sclerosis (ALS)-associated mutant SOD proteins can protect motor neurons in culture from trophic factor deprivation as efficiently as wild-type SOD. However, the removal of zinc from either mutant or wild-type SOD results in apoptosis of motor neurons through a copper- and peroxynitrite-dependent mechanism. It has also been shown that motor neurons isolated from transgenic mice expressing mutant SODs survive well in culture but undergo apoptosis when exposed to nitric oxide via a Fas-dependent mechanism. We combined these two parallel approaches for understanding SOD toxicity in ALS and found that zinc-deficient SOD-induced motor neuron death required Fas activation, whereas the nitric oxide-dependent death of G93A SOD-expressing motor neurons required copper and involved peroxynitrite formation. Surprisingly, motor neuron death doubled when Cu,Zn-SOD protein was either delivered intracellularly to G93A SOD-expressing motor neurons or co-delivered with zinc-deficient SOD to nontransgenic motor neurons. These results could be rationalized by biophysical data showing that heterodimer formation of Cu,Zn-SOD with zinc-deficient SOD prevented the monomerization and subsequent aggregation of zinc-deficient SOD under thiol-reducing conditions. ALS mutant SOD was also stabilized by mutating cysteine 111 to serine, which greatly increased the toxicity of zinc-deficient SOD. Thus, stabilization of ALS mutant SOD by two different approaches augmented its toxicity to motor neurons. Taken together, these results are consistent with copper-containing zinc-deficient SOD being the elusive "partially unfolded intermediate" responsible for the toxic gain of function conferred by ALS mutant SOD.
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Affiliation(s)
- Mary Anne Sahawneh
- From the Burke Medical Research Institute, White Plains, New York 10605, ,the Department of Neurology and Neurosciences, Weill Medical College, New York, New York 10022
| | - Karina C. Ricart
- the Departments of Pathology and ,the Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294, and
| | - Blaine R. Roberts
- the Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331
| | | | - Manuela Basso
- From the Burke Medical Research Institute, White Plains, New York 10605, ,the Department of Neurology and Neurosciences, Weill Medical College, New York, New York 10022
| | - Yaozu Ye
- From the Burke Medical Research Institute, White Plains, New York 10605
| | - John Sahawneh
- From the Burke Medical Research Institute, White Plains, New York 10605
| | - Maria Clara Franco
- From the Burke Medical Research Institute, White Plains, New York 10605, ,the Department of Neurology and Neurosciences, Weill Medical College, New York, New York 10022
| | - Joseph S. Beckman
- the Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331
| | - Alvaro G. Estévez
- From the Burke Medical Research Institute, White Plains, New York 10605, ,the Department of Neurology and Neurosciences, Weill Medical College, New York, New York 10022, , To whom correspondence should be addressed. Tel.: 541-737-4517; Fax: 541-737-0481; E-mail:
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Banci L, Bertini I, Cantini F, Ciofi-Baffoni S. Cellular copper distribution: a mechanistic systems biology approach. Cell Mol Life Sci 2010; 67:2563-89. [PMID: 20333435 PMCID: PMC11115773 DOI: 10.1007/s00018-010-0330-x] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Revised: 01/27/2010] [Accepted: 02/22/2010] [Indexed: 01/01/2023]
Abstract
Copper is an essential but potentially harmful trace element required in many enzymatic processes involving redox chemistry. Cellular copper homeostasis in mammals is predominantly maintained by regulating copper transport through the copper import CTR proteins and the copper exporters ATP7A and ATP7B. Once copper is imported into the cell, several pathways involving a number of copper proteins are responsible for trafficking it specifically where it is required for cellular life, thus avoiding the release of harmful free copper ions. In this study we review recent progress made in understanding the molecular mechanisms of copper transport in cells by analyzing structural features of copper proteins, their mode of interaction, and their thermodynamic and kinetic parameters, thus contributing to systems biology of copper within the cell.
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Affiliation(s)
- Lucia Banci
- Department of Chemistry, Magnetic Resonance Center CERM, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence Italy
| | - Ivano Bertini
- Department of Chemistry, Magnetic Resonance Center CERM, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence Italy
| | - Francesca Cantini
- Department of Chemistry, Magnetic Resonance Center CERM, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence Italy
| | - Simone Ciofi-Baffoni
- Department of Chemistry, Magnetic Resonance Center CERM, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence Italy
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Barber SC, Shaw PJ. Oxidative stress in ALS: key role in motor neuron injury and therapeutic target. Free Radic Biol Med 2010; 48:629-41. [PMID: 19969067 DOI: 10.1016/j.freeradbiomed.2009.11.018] [Citation(s) in RCA: 425] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 10/16/2009] [Accepted: 11/29/2009] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder characterized by death of motor neurons leading to muscle wasting, paralysis, and death, usually within 2-3 years of symptom onset. The causes of ALS are not completely understood, and the neurodegenerative processes involved in disease progression are diverse and complex. There is substantial evidence implicating oxidative stress as a central mechanism by which motor neuron death occurs, including elevated markers of oxidative damage in ALS patient spinal cord and cerebrospinal fluid and mutations in the antioxidant enzyme superoxide dismutase 1 (SOD1) causing approximately 20% of familial ALS cases. However, the precise mechanism(s) by which mutant SOD1 leads to motor neuron degeneration has not been defined with certainty, and the ultimate trigger for increased oxidative stress in non-SOD1 cases remains unclear. Although some antioxidants have shown potential beneficial effects in animal models, human clinical trials of antioxidant therapies have so far been disappointing. Here, the evidence implicating oxidative stress in ALS pathogenesis is reviewed, along with how oxidative damage triggers or exacerbates other neurodegenerative processes, and we review the trials of a variety of antioxidants as potential therapies for ALS.
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Affiliation(s)
- Siân C Barber
- Academic Neurology Unit and Sheffield Care & Research Centre for Motor Neuron Disorders, Department of Neuroscience, University of Sheffield, Sheffield S10 2RX, UK
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38
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Metal ion physiopathology in neurodegenerative disorders. Neuromolecular Med 2009; 11:223-38. [PMID: 19946766 DOI: 10.1007/s12017-009-8102-1] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Accepted: 10/14/2009] [Indexed: 12/14/2022]
Abstract
Metal dyshomeostasis in the brain (BMD) has often been proposed as a possible cause for several neurodegenerative disorders (NDs). Nevertheless, the precise nature of the biochemical mechanisms of metal involvement in NDs is still largely unknown. Mounting evidence suggests that normal aging itself is characterized by, among other features, a significant degree of metal ion dysmetabolism in the brain. This is probably the result of a progressive deterioration of the metal regulatory systems and, at least in some cases, of life-long metal exposure and brain accumulation. Although alterations of metal metabolism do occur to some extent in normal aging, they appear to be highly enhanced under various neuropathological conditions, causing increased oxidative stress and favoring abnormal metal-protein interactions. Intriguingly, despite the fact that most common NDs have a distinct etiological basis, they share striking similarities as they are all characterized by a documented brain metal impairment. This review will primarily focus on the alterations of metal homeostasis that are observed in normal aging and in Alzheimer's disease. We also present a brief survey on BMD in other NDs (Amyotrophic Lateral Sclerosis, Parkinson's, and Prion Protein disease) in order to highlight what represents the most reliable evidence supporting a crucial involvement of metals in neurodegeneration. The opportunities for metal-targeted pharmacological strategies in the major NDs are briefly outlined as well.
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39
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Chen Y, Stankovic R, Cullen KM, Meininger V, Garner B, Coggan S, Grant R, Brew BJ, Guillemin GJ. The kynurenine pathway and inflammation in amyotrophic lateral sclerosis. Neurotox Res 2009; 18:132-42. [PMID: 19921535 DOI: 10.1007/s12640-009-9129-7] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 09/22/2009] [Accepted: 10/27/2009] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive and fatal motor neuron disease of unknown pathogenesis. The kynurenine pathway (KP), activated during neuroinflammation, is emerging as a possible contributory factor in ALS. The KP is the major route for tryptophan (TRP) catabolism. The intermediates generated can be either neurotoxic, such as quinolinic acid (QUIN), or neuroprotective, such as picolinic acid (PIC), an important endogenous chelator. The first and inducible enzyme of the pathway is indoleamine 2,3-dioxygenase (IDO). The present study aimed to characterize the expression of the KP in cerebrospinal fluid (CSF), serum and central nervous system (CNS) tissue of ALS patients. Using high performance liquid chromatography, we analysed the levels of TRP and kynurenine (KYN), and, with gas chromatography/mass spectrometry, the levels of PIC and QUIN, in the CSF and serum of ALS patients and control subjects. Immunohistochemistry was employed to determine the expression of QUIN, IDO and human leukocyte antigen-DR (HLA-DR) in sections of brain and spinal cord from ALS patients. There were significantly increased levels of CSF and serum TRP (P < 0.0001), KYN (P < 0.0001) and QUIN (P < 0.05) and decreased levels of serum PIC (P < 0.05) in ALS samples. There was a significant increase in activated microglia expressing HLA-DR (P < 0.0001) and increased neuronal and microglial expression of IDO and QUIN in ALS motor cortex and spinal cord. We show the presence of neuroinflammation in ALS and provide the first strong evidence for the involvement of the KP in ALS. These data point to an inflammation-driven excitotoxic-chelation defective mechanism in ALS, which may be amenable to inhibitors of the KP.
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Affiliation(s)
- Yiquan Chen
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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40
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Tiwari A, Liba A, Sohn SH, Seetharaman SV, Bilsel O, Matthews CR, Hart PJ, Valentine JS, Hayward LJ. Metal deficiency increases aberrant hydrophobicity of mutant superoxide dismutases that cause amyotrophic lateral sclerosis. J Biol Chem 2009; 284:27746-58. [PMID: 19651777 DOI: 10.1074/jbc.m109.043729] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mechanisms by which mutant variants of Cu/Zn-superoxide dismutase (SOD1) cause familial amyotrophic lateral sclerosis are not clearly understood. Evidence to date suggests that altered conformations of amyotrophic lateral sclerosis mutant SOD1s trigger perturbations of cellular homeostasis that ultimately cause motor neuron degeneration. In this study we correlated the metal contents and disulfide bond status of purified wild-type (WT) and mutant SOD1 proteins to changes in electrophoretic mobility and surface hydrophobicity as detected by 1-anilinonaphthalene-8-sulfonic acid (ANS) fluorescence. As-isolated WT and mutant SOD1s were copper-deficient and exhibited mobilities that correlated with their expected negative charge. However, upon disulfide reduction and demetallation at physiological pH, both WT and mutant SOD1s underwent a conformational change that produced a slower mobility indicative of partial unfolding. Furthermore, although ANS did not bind appreciably to the WT holoenzyme, incubation of metal-deficient WT or mutant SOD1s with ANS increased the ANS fluorescence and shifted its peak toward shorter wavelengths. This increased interaction with ANS was greater for the mutant SOD1s and could be reversed by the addition of metal ions, especially Cu(2+), even for SOD1 variants incapable of forming the disulfide bond. Overall, our findings support the notion that misfolding associated with metal deficiency may facilitate aberrant interactions of SOD1 with itself or with other cellular constituents and may thereby contribute to neuronal toxicity.
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Affiliation(s)
- Ashutosh Tiwari
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA.
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41
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Abstract
The causes of amyotrophic lateral sclerosis (ALS) are poorly understood. A small proportion, about 2%, is associated with a mutation in the superoxide dismutase (SOD1) gene, and mice expressing this mutant gene exhibit a progressive, ALS-like neurodegenerative disease. Studies of these animals, as well as of human post mortem tissue, reveal the presence of multiple pathological processes, including oxidative stress, glutamate excitotoxicity, neuroinflammation, mitochondrial degeneration, alterations in neurofilaments and neurotubules, mitochondrial damage, aggregation of proteins, abnormalities in growth factors, and apoptosis. We propose that alterations in the disposition of zinc ions may be important in the initiation and development of ALS. SOD1 binds zinc, and many of the mutant forms of this enzyme associated with ALS show altered zinc binding. Alterations in the expression of metallothioneins (MTs), which regulate cellular levels of zinc, have been reported in mutant SOD1 mice, and deletion of MTs in these animals accelerates disease progression. Zinc plays a key role in all the pathological processes associated with ALS. Our zinc hypothesis also may help explain evidence for environmental factors in some cases of ALS, such as in the Chamorro tribe in Guam and in the Gulf War.
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Affiliation(s)
- Andrew P Smith
- The Forbes Norris ALS Research Center, California Pacific Medical Center Research Institute, California 94115, USA
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42
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Bolognin S, Drago D, Messori L, Zatta P. Chelation therapy for neurodegenerative diseases. Med Res Rev 2009; 29:547-70. [DOI: 10.1002/med.20148] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Leitch JM, Jensen LT, Bouldin SD, Outten CE, Hart PJ, Culotta VC. Activation of Cu,Zn-superoxide dismutase in the absence of oxygen and the copper chaperone CCS. J Biol Chem 2009; 284:21863-21871. [PMID: 19542232 DOI: 10.1074/jbc.m109.000489] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Eukaryotic Cu,Zn-superoxide dismutases (SOD1s) are generally thought to acquire the essential copper cofactor and intramolecular disulfide bond through the action of the CCS copper chaperone. However, several metazoan SOD1s have been shown to acquire activity in vivo in the absence of CCS, and the Cu,Zn-SOD from Caenorhabditis elegans has evolved complete independence from CCS. To investigate SOD1 activation in the absence of CCS, we compared and contrasted the CCS-independent activation of C. elegans and human SOD1 to the strict CCS-dependent activation of Saccharomyces cerevisiae SOD1. Using a yeast expression system, both pathways were seen to acquire copper derived from cell surface transporters and compete for the same intracellular pool of copper. Like CCS, CCS-independent activation occurs rapidly with a preexisting pool of apo-SOD1 without the need for new protein synthesis. The two pathways, however, strongly diverge when assayed for the SOD1 disulfide. SOD1 molecules that are activated without CCS exhibit disulfide oxidation in vivo without oxygen and under copper-depleted conditions. The strict requirement for copper, oxygen, and CCS in disulfide bond oxidation appears exclusive to yeast SOD1, and we find that a unique proline at position 144 in yeast SOD1 is responsible for this disulfide effect. CCS-dependent and -independent pathways also exhibit differential requirements for molecular oxygen. CCS activation of SOD1 requires oxygen, whereas the CCS-independent pathway is able to activate SOD1s even under anaerobic conditions. In this manner, Cu,Zn-SOD from metazoans may retain activity over a wide range of physiological oxygen tensions.
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Affiliation(s)
- Jeffry M Leitch
- Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Laran T Jensen
- Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Samantha D Bouldin
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Caryn E Outten
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - P John Hart
- Department of Biochemistry and X-ray Crystallography Core Laboratory, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Valeria C Culotta
- Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
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Kim J, Kim TY, Hwang JJ, Lee JY, Shin JH, Gwag BJ, Koh JY. Accumulation of labile zinc in neurons and astrocytes in the spinal cords of G93A SOD-1 transgenic mice. Neurobiol Dis 2009; 34:221-9. [DOI: 10.1016/j.nbd.2009.01.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Revised: 01/07/2009] [Accepted: 01/09/2009] [Indexed: 10/21/2022] Open
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D'Orazio M, Cervoni L, Giartosio A, Rotilio G, Battistoni A. Thermal stability and redox properties of M. tuberculosis CuSOD. Arch Biochem Biophys 2009; 486:119-24. [PMID: 19383490 DOI: 10.1016/j.abb.2009.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 04/07/2009] [Accepted: 04/11/2009] [Indexed: 11/19/2022]
Abstract
The superoxide dismutase from Mycobacterium tuberculosis is the only Cu-containing superoxide dismutase that lacks zinc in the active site. To explore the structural properties of this unusual enzyme, we have investigated its stability by differential scanning calorimetry. We have found that the holo-enzyme is significantly more stable than the apo-protein or the partially metallated enzyme, but that its melting temperature is markedly lower than that of all the other characterized eukaryotic and prokaryotic Cu,Zn superoxide dismutases. We have also observed that, unlike the zinc-free eukaryotic or bacterial enzymes, the active site copper of the mycobacterial enzyme is not reduced by ascorbate, confirming that its redox properties are comparable to those typical of the enzymes containing zinc in the active site. Our findings highlight the role of zinc in conferring stability to Cu,Zn superoxide dismutases and indicate that the structural rearrangements observed in M. tuberculosis Cu,SOD compensate for the absence of zinc in achieving a fully active enzyme.
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46
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Rumfeldt JA, Lepock JR, Meiering EM. Unfolding and Folding Kinetics of Amyotrophic Lateral Sclerosis-Associated Mutant Cu,Zn Superoxide Dismutases. J Mol Biol 2009; 385:278-98. [DOI: 10.1016/j.jmb.2008.10.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 09/26/2008] [Accepted: 10/01/2008] [Indexed: 02/06/2023]
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47
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Soares DC, Barlow PN, Porteous DJ, Devon RS. An interrupted beta-propeller and protein disorder: structural bioinformatics insights into the N-terminus of alsin. J Mol Model 2008; 15:113-22. [PMID: 19023603 DOI: 10.1007/s00894-008-0381-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Accepted: 11/05/2008] [Indexed: 12/11/2022]
Abstract
Defects in the human ALS2 gene, which encodes the 1,657-amino-acid residue protein alsin, are linked to several related motor neuron diseases. We created a structural model for the N-terminal 690-residue region of alsin through comparative modelling based on regulator of chromosome condensation 1 (RCC1). We propose that this alsin region contains seven RCC1-like repeats in a seven-bladed beta-propeller structure. The propeller is formed by a double clasp arrangement containing two segments (residues 1-218 and residues 525-690). The 306-residue insert region, predicted to lie within blade 5 and to be largely disordered, is poorly conserved across species. Surface patches of evolutionary conservation probably indicate locations of binding sites. Both disease-causing missense mutations-Cys157Tyr and Gly540Glu-are buried in the propeller and likely to be structurally disruptive. This study aids design of experimental studies by highlighting the importance of construct length, will enhance interpretation of protein-protein interactions, and enable rational site-directed mutagenesis.
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Affiliation(s)
- Dinesh C Soares
- Medical Genetics Section, Molecular Medicine Centre, Institute of Genetics and Molecular Medicine, Western General Hospital, University of Edinburgh, Crewe Road, Edinburgh EH42XU, UK.
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48
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Furukawa Y, Kaneko K, Yamanaka K, O'Halloran TV, Nukina N. Complete loss of post-translational modifications triggers fibrillar aggregation of SOD1 in the familial form of amyotrophic lateral sclerosis. J Biol Chem 2008; 283:24167-76. [PMID: 18552350 PMCID: PMC3259764 DOI: 10.1074/jbc.m802083200] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Revised: 05/13/2008] [Indexed: 11/06/2022] Open
Abstract
Dominant mutations in Cu,Zn-superoxide dismutase (SOD1) cause a familial form of amyotrophic lateral sclerosis (fALS), and aggregation of mutant SOD1 has been proposed to play a role in neurodegeneration. A growing body of evidence suggests that fALS-causing mutations destabilize the native structure of SOD1, leading to aberrant protein interactions for aggregation. SOD1 becomes stabilized and enzymatically active after copper and zinc binding and intramolecular disulfide formation, but it remains unknown which step(s) in the SOD1 maturation process is important in the pathological aggregation. In this study we have shown that apoSOD1 without disulfide is the most facile state for formation of amyloid-like fibrillar aggregates. fALS mutations impair either zinc binding, disulfide formation, or both, leading to accumulation of the aggregation-prone, apo, and disulfide-reduced SOD1. Moreover, we have found that the copper chaperone for SOD1 (CCS) facilitates maturation of SOD1 and that CCS overexpression ameliorates intracellular aggregation of mutant SOD1 in vivo. Based on our in vivo and in vitro results, we propose that facilitation of post-translational modifications is a promising strategy to reduce SOD1 aggregation in the cell.
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Affiliation(s)
- Yoshiaki Furukawa
- Laboratory for Structural
Neuropathology, Yamanaka Research
Unit, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan and
Chemistry of Life Processes
Institute, Northwestern University, Evanston, Illinois 60208-3113
| | - Kumi Kaneko
- Laboratory for Structural
Neuropathology, Yamanaka Research
Unit, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan and
Chemistry of Life Processes
Institute, Northwestern University, Evanston, Illinois 60208-3113
| | - Koji Yamanaka
- Laboratory for Structural
Neuropathology, Yamanaka Research
Unit, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan and
Chemistry of Life Processes
Institute, Northwestern University, Evanston, Illinois 60208-3113
| | - Thomas V. O'Halloran
- Laboratory for Structural
Neuropathology, Yamanaka Research
Unit, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan and
Chemistry of Life Processes
Institute, Northwestern University, Evanston, Illinois 60208-3113
| | - Nobuyuki Nukina
- Laboratory for Structural
Neuropathology, Yamanaka Research
Unit, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan and
Chemistry of Life Processes
Institute, Northwestern University, Evanston, Illinois 60208-3113
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Tokuda E, Ono SI, Ishige K, Naganuma A, Ito Y, Suzuki T. Metallothionein proteins expression, copper and zinc concentrations, and lipid peroxidation level in a rodent model for amyotrophic lateral sclerosis. Toxicology 2007; 229:33-41. [PMID: 17097207 DOI: 10.1016/j.tox.2006.09.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Revised: 09/06/2006] [Accepted: 09/24/2006] [Indexed: 11/28/2022]
Abstract
It has been hypothesized that copper-mediated oxidative stress contributes to the pathogenesis of familial amyotrophic lateral sclerosis (ALS), a fatal motor neuron disease in humans. To verify this hypothesis, we examined the copper and zinc concentrations and the amounts of lipid peroxides, together with that of the expression of metallothionein (MT) isoforms in a mouse model [superoxide dismutase1 transgenic (SOD1 Tg) mouse] of ALS. The expression of MT-I and MT-II (MT-I/II) isoforms were measured together with Western blotting, copper level, and lipid peroxides amounts increased in an age-dependent manner in the spinal cord, the region responsible for motor paralysis. A significant increase was already seen as early as 8-week-old SOD1 Tg mice, at which time the mice had not yet exhibited motor paralysis, and showed a further increase at 16 weeks of age, when paralysis was evident. Inversely, the spinal zinc level had significantly decreased at both 8 and 16 weeks of age. The third isoform, the MT-III level, remained at the same level as an 8-week-old wild-type mouse, finally increasing to a significant level at 16 weeks of age. It has been believed that a mutant SOD1 protein, encoded by a mutant SOD1, gains a novel cytotoxic function while maintaining its original enzymatic activity, and causes motor neuron death (gain-of-toxic function). Copper-mediated oxidative stress seems to be a probable underlying pathogenesis of gain-of-toxic function. Taking the above current concepts and the classic functions of MT into account, MTs could have a disease modifying property: the MT-I/II isoform for attenuating the gain-of-toxic function at the early stage of the disease, and the MT-III isoform at an advanced stage.
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Affiliation(s)
- Eiichi Tokuda
- Laboratory of Clinical Pharmacy, College of Pharmacy, Nihon University, Chiba, Japan
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Rakhit R, Chakrabartty A. Structure, folding, and misfolding of Cu,Zn superoxide dismutase in amyotrophic lateral sclerosis. Biochim Biophys Acta Mol Basis Dis 2006; 1762:1025-37. [PMID: 16814528 DOI: 10.1016/j.bbadis.2006.05.004] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Revised: 05/15/2006] [Accepted: 05/16/2006] [Indexed: 11/16/2022]
Abstract
Fourteen years after the discovery that mutations in Cu, Zn superoxide dismutase (SOD1) cause a subset of familial amyotrophic lateral sclerosis (fALS), the mechanism by which mutant SOD1 exerts toxicity remains unknown. The two principle hypotheses are (a) oxidative damage stemming from aberrant SOD1 redox chemistry, and (b) misfolding of the mutant protein. Here we review the structure and function of wild-type SOD1, as well as the changes to the structure and function in mutant SOD1. The relative merits of the two hypotheses are compared and a common unifying principle is outlined. Lastly, the potential for therapies targeting SOD1 misfolding is discussed.
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Affiliation(s)
- Rishi Rakhit
- Department of Biochemistry, University of Toronto, University Health Network, Toronto Medical Discovery Tower, Medical and Related Sciences (MaRS), 101 College Street, Toronto, ON, Canada, M5G 1L7
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