151
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Murakami K, Shimizu T, Irie K. Formation of the 42-mer Amyloid β Radical and the Therapeutic Role of Superoxide Dismutase in Alzheimer's Disease. JOURNAL OF AMINO ACIDS 2011; 2011:654207. [PMID: 22332002 PMCID: PMC3276080 DOI: 10.4061/2011/654207] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 12/16/2010] [Indexed: 11/20/2022]
Abstract
Oxidative stress is closely involved in age-related diseases and ageing itself. There is evidence of the leading contribution of oxidative damage to neurodegenerative disease, in contrast to other diseases where oxidative stress plays a secondary role. The 42-mer amyloid β (Aβ42) peptide is thought to be a culprit in the pathogenesis of Alzheimer's disease (AD). Aβ42 aggregates form the oligomeric assembly and show neurotoxicity, causing synaptic dysfunction. Aβ42 also induces tissue oxidation (DNA/RNA, proteins, and lipids) through trace metals (Cu, Zn, and Fe), which can be protected by antioxidant enzymes, vitamin C, and vitamin E. Superoxide dismutase catalyzes the conversion of toxic superoxide radical to less reactive hydrogen peroxide, contributing to protection from AD. Here we review the involvement of oxidative stress in AD progression induced from an imbalance between the radical formation of Aβ42 itself together with unique turn structure at positions Glu22 and Asp23 and several defense systems.
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Affiliation(s)
- Kazuma Murakami
- Laboratory of Organic Chemistry in Life Science, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Takahiko Shimizu
- Molecular Gerontology, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo 173-0015, Japan
| | - Kazuhiro Irie
- Laboratory of Organic Chemistry in Life Science, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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152
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Dumont M, Lin MT, Beal MF. Mitochondria and antioxidant targeted therapeutic strategies for Alzheimer's disease. J Alzheimers Dis 2010; 20 Suppl 2:S633-43. [PMID: 20421689 DOI: 10.3233/jad-2010-100507] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Oxidative stress and mitochondrial dysfunction are important features present in Alzheimer's disease (AD). They appear early and contribute to disease progression, both in human postmortem AD brains as well as in transgenic AD mouse brains. For this reason, targeting oxidative stress and mitochondria in AD may lead to the development of promising therapeutic strategies. Several exogenous antioxidant compounds have been tested and found beneficial in transgenic AD mice, such as vitamins and spices. However, their efficacy was much more modest in human trials. More recently, new strategies have been elaborated to promote endogenous antioxidant systems. Different pathways involved in oxidative stress response have been identified. Compounds able to upregulate these pathways are being generated and tested in animal models of AD and in human patients. Upregulation of antioxidant gene expression was beneficial in mice, giving hope for future avenues in the treatment of AD and other neurodegenerative disorders.
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Affiliation(s)
- Magali Dumont
- Weill Cornell Medical College, Department of Neurology and Neuroscience, New York, NY, USA
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153
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Choudhry F, Howlett DR, Richardson JC, Francis PT, Williams RJ. Pro-oxidant diet enhances β/γ secretase-mediated APP processing in APP/PS1 transgenic mice. Neurobiol Aging 2010; 33:960-8. [PMID: 20724034 DOI: 10.1016/j.neurobiolaging.2010.07.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Revised: 07/08/2010] [Accepted: 07/09/2010] [Indexed: 01/08/2023]
Abstract
The etiology of Alzheimer's disease (AD) is complex with oxidative stress being a possible contributory factor to pathogenesis and disease progression. TASTPM transgenic mice expressing familial AD-associated amyloid precursor protein (APPswe) and presenilin transgenes (PS1M146V) show increased brain amyloid beta (Aβ) levels and Aβ plaques from 3 months. We tested if enhancing oxidative stress through diet would accelerate Aβ-related pathology. TASTPM were fed a pro-oxidant diet for 3 months resulting in increased brain levels of protein carbonyls, increased Nrf2, and elevated concentrations of glutathione (GSH). The diet increased both amyloid precursor protein (APP) and Aβ in the cortex of TASTPM but did not alter Aβ plaque load, presenilin 1, or β-secretase (BACE1) expression. TASTPM cortical neurons were cultured under similar pro-oxidant conditions resulting in increased levels of APP and Aβ likely as a result of enhanced β/γ secretase processing of APP. Thus, pro-oxidant conditions increase APP levels and enhance BACE1-mediated APP processing and in doing so might contribute to pathogenesis in AD.
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Affiliation(s)
- Fahd Choudhry
- Wolfson Centre for Age-Related Diseases, King's College London, London, UK
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154
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Wang DD, Kriegstein AR. Blocking early GABA depolarization with bumetanide results in permanent alterations in cortical circuits and sensorimotor gating deficits. ACTA ACUST UNITED AC 2010; 21:574-87. [PMID: 20624842 DOI: 10.1093/cercor/bhq124] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A high incidence of seizures occurs during the neonatal period when immature networks are hyperexcitable and susceptible to hypersyncrhonous activity. During development, γ-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in adults, typically excites neurons due to high expression of the Na(+)-K(+)-2Cl(-) cotransporter (NKCC1). NKCC1 facilitates seizures because it renders GABA activity excitatory through intracellular Cl(-) accumulation, while blocking NKCC1 with bumetanide suppresses seizures. Bumetanide is currently being tested in clinical trials for treatment of neonatal seizures. By blocking NKCC1 with bumetanide during cortical development, we found a critical period for the development of α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate synapses. Disruption of GABA signaling during this window resulted in permanent decreases in excitatory synaptic transmission and sensorimotor gating deficits, a common feature in schizophrenia. Our study identifies an essential role for GABA-mediated depolarization in regulating the balance between cortical excitation and inhibition during a critical period and suggests a cautionary approach for using bumetanide in treating neonatal seizures.
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Affiliation(s)
- Doris D Wang
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco CA 94143, USA.
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155
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Holley AK, Dhar SK, St Clair DK. Manganese superoxide dismutase vs. p53: regulation of mitochondrial ROS. Mitochondrion 2010; 10:649-61. [PMID: 20601193 DOI: 10.1016/j.mito.2010.06.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2009] [Revised: 06/18/2010] [Accepted: 06/22/2010] [Indexed: 01/10/2023]
Abstract
Coordination of mitochondrial and nuclear activities is vital for cellular homeostasis, and many signaling molecules and transcription factors are regulated by mitochondria-derived reactive oxygen species (ROS) to carry out this interorganellar communication. The tumor suppressor p53 regulates myriad cellular functions through transcription-dependent and -independent mechanisms at both the nucleus and mitochondria. p53 affect mitochondrial ROS production, in part, by regulating the expression of the mitochondrial antioxidant enzyme manganese superoxide dismutase (MnSOD). Recent evidence suggests mitochondrial regulation of p53 activity through mechanisms that affect ROS production, and a breakdown of communication amongst mitochondria, p53, and the nucleus can have broad implications in disease development.
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Affiliation(s)
- Aaron K Holley
- Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536, United States
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156
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Zhuo JM, Portugal GS, Kruger WD, Wang H, Gould TJ, Pratico D. Diet-induced hyperhomocysteinemia increases amyloid-beta formation and deposition in a mouse model of Alzheimer's disease. Curr Alzheimer Res 2010; 7:140-9. [PMID: 19939226 DOI: 10.2174/156720510790691326] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Accepted: 10/25/2009] [Indexed: 11/22/2022]
Abstract
Hyperhomocysteinemia (HHcy) has been recognized as a risk factor for developing Alzheimer's disease (AD). However, its underlying molecular mechanisms are still elusive. Here we show that HHcy induces an elevation of amyloid beta (Abeta) levels and deposition, as well as behavioral impairments, in a mouse model of AD-like amyloidosis, the Tg2576 mice. This elevation is not associated with significant change of the steady state levels of the Abeta precursor protein (APP), beta- or alpha-secretase pathways, nor with the Abeta catabolic pathways. By contrast, HHcy significantly reduces glycogen synthase kinase 3 (GSK3) Ser21/9 phosphorylation, but not total GSK3 protein levels. Similar results are obtained in brains homogenates from a genetic mouse model of HHcy. In vitro studies show that homocysteine increases Abeta formation, reduces phosphorylated GSK3 levels, without changes in total APP and its metabolism, and these effects are prevented by selective GSK3 inhibition. Overall, these data support a potential link between GSK3 and the pro-amyloidotic effect of HHcy in vivo and in vitro.
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Affiliation(s)
- J-M Zhuo
- Department of Pharmacology, Neuroscience Program Temple University School of Medicine, Philadelphia, PA 19140, USA
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157
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Massaad CA, Amin SK, Hu L, Mei Y, Klann E, Pautler RG. Mitochondrial superoxide contributes to blood flow and axonal transport deficits in the Tg2576 mouse model of Alzheimer's disease. PLoS One 2010; 5:e10561. [PMID: 20479943 PMCID: PMC2866668 DOI: 10.1371/journal.pone.0010561] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 04/15/2010] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is a neurodegenerative disease characterized by the progressive decline in cognitive functions and the deposition of aggregated amyloid beta (Abeta) into senile plaques and the protein tau into tangles. In addition, a general state of oxidation has long been known to be a major hallmark of the disease. What is not known however, are the mechanisms by which oxidative stress contributes to the pathology of AD. METHODOLOGY/PRINCIPAL FINDINGS In the current study, we used a mouse model of AD and genetically boosted its ability to quench free radicals of specific mitochondrial origin. We found that such manipulation conferred to the AD mice protection against vascular as well as neuronal deficits that typically affect them. We also found that the vascular deficits are improved via antioxidant modulation of the endothelial nitric oxide synthase, an enzyme primarily responsible for the production of nitric oxide, while neuronal deficits are improved via modulation of the phosphorylation status of the protein tau, which is a neuronal cytoskeletal stabilizer. CONCLUSIONS/SIGNIFICANCE These findings directly link free radicals of specific mitochondrial origin to AD-associated vascular and neuronal pathology.
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Affiliation(s)
- Cynthia A. Massaad
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Samir K. Amin
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lingyun Hu
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Yuan Mei
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Cognitive Science, Rice University, Houston, Texas, United States of America
| | - Eric Klann
- Center for Neural Science, New York University, New York, New York, United States of America
| | - Robia G. Pautler
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
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158
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Salek RM, Xia J, Innes A, Sweatman BC, Adalbert R, Randle S, McGowan E, Emson PC, Griffin JL. A metabolomic study of the CRND8 transgenic mouse model of Alzheimer's disease. Neurochem Int 2010; 56:937-47. [PMID: 20398713 DOI: 10.1016/j.neuint.2010.04.001] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Revised: 04/04/2010] [Accepted: 04/06/2010] [Indexed: 11/15/2022]
Abstract
Alzheimer's disease is the most common neurodegenerative disease of the central nervous system characterized by a progressive loss in memory and deterioration of cognitive functions. In this study the transgenic mouse TgCRND8, which encodes a mutant form of the amyloid precursor protein 695 with both the Swedish and Indiana mutations and develops extracellular amyloid beta-peptide deposits as early as 2-3 months, was investigated. Extract from eight brain regions (cortex, frontal cortex, cerebellum, hippocampus, olfactory bulb, pons, midbrain and striatum) were studied using (1)H NMR spectroscopy. Analysis of the NMR spectra discriminated control from APP695 tissues in hippocampus, cortex, frontal cortex, midbrain and cerebellum, with hippocampal and cortical region being most affected. The analysis of the corresponding loading plots for these brain regions indicated a decrease in N-acetyl-L-aspartate, glutamate, glutamine, taurine (exception hippocampus), gamma-amino butyric acid, choline and phosphocholine (combined resonances), creatine, phosphocreatine and succinate in hippocampus, cortex, frontal cortex (exception gamma-amino butyric acid) and midbrain of affected animals. An increase in lactate, aspartate, glycine (except in midbrain) and other amino acids including alanine (exception frontal cortex), leucine, iso-leucine, valine and water soluble free fatty acids (0.8-0.9 and 1.2-1.3 ppm) were observed in the TgCRND8 mice. Our findings demonstrate that the perturbations in metabolism are more widespread and include the cerebellum and midbrain. Furthermore, metabolic perturbations are associated with a wide range of metabolites which could improve the diagnosis and monitoring of the progression of Alzheimer's disease.
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Affiliation(s)
- Reza M Salek
- Department of Biochemistry, The Hopkins Building, Tennis Court Road, University of Cambridge, Cambridge CB21QW, UK
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159
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Fukui M, Zhu BT. Mitochondrial superoxide dismutase SOD2, but not cytosolic SOD1, plays a critical role in protection against glutamate-induced oxidative stress and cell death in HT22 neuronal cells. Free Radic Biol Med 2010; 48:821-30. [PMID: 20060889 PMCID: PMC2861908 DOI: 10.1016/j.freeradbiomed.2009.12.024] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 12/10/2009] [Accepted: 12/30/2009] [Indexed: 11/20/2022]
Abstract
Oxidative cell death is an important contributing factor in neurodegenerative diseases. Using HT22 mouse hippocampal neuronal cells as a model, we sought to demonstrate that mitochondria are crucial early targets of glutamate-induced oxidative cell death. We show that when HT22 cells were transfected with shRNA for knockdown of the mitochondrial superoxide dismutase (SOD2), these cells became more susceptible to glutamate-induced oxidative cell death. The increased susceptibility was accompanied by increased accumulation of mitochondrial superoxide and loss of normal mitochondrial morphology and function at early time points after glutamate exposure. However, overexpression of SOD2 in these cells reduced the mitochondrial superoxide level, protected mitochondrial morphology and functions, and provided resistance against glutamate-induced oxidative cytotoxicity. The change in the sensitivity of these SOD2-altered HT22 cells was neurotoxicant-specific, because the cytotoxicity of hydrogen peroxide was not altered in these cells. In addition, selective knockdown of the cytosolic SOD1 in cultured HT22 cells did not appreciably alter their susceptibility to either glutamate or hydrogen peroxide. These findings show that the mitochondrial SOD2 plays a critical role in protecting neuronal cells from glutamate-induced oxidative stress and cytotoxicity. These data also indicate that mitochondria are important early targets of glutamate-induced oxidative neurotoxicity.
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Affiliation(s)
- Masayuki Fukui
- Department of Pharmacology, Toxicology and Therapeutics, School of Medicine, University of Kansas Medical Center, Kansas City, KS 66160, USA
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160
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Salmon AB, Richardson A, Pérez VI. Update on the oxidative stress theory of aging: does oxidative stress play a role in aging or healthy aging? Free Radic Biol Med 2010; 48:642-55. [PMID: 20036736 PMCID: PMC2819595 DOI: 10.1016/j.freeradbiomed.2009.12.015] [Citation(s) in RCA: 301] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 12/14/2009] [Accepted: 12/18/2009] [Indexed: 12/22/2022]
Abstract
The oxidative stress theory of aging predicts that manipulations that alter oxidative stress/damage will alter aging. The gold standard for determining whether aging is altered is life span, i.e., does altering oxidative stress/damage change life span? Mice with genetic manipulations in their antioxidant defense system designed to directly address this prediction have, with few exceptions, shown no change in life span. However, when these transgenic/knockout mice are tested using models that develop various types of age-related pathology, they show alterations in progression and/or severity of pathology as predicted by the oxidative stress theory: increased oxidative stress accelerates pathology and reduced oxidative stress retards pathology. These contradictory observations might mean that (a) oxidative stress plays a very limited, if any, role in aging but a major role in health span and/or (b) the role that oxidative stress plays in aging depends on environment. In environments with minimal stress, as expected under optimal husbandry, oxidative damage plays little role in aging. However, under chronic stress, including pathological phenotypes that diminish optimal health, oxidative stress/damage plays a major role in aging. Under these conditions, enhanced antioxidant defenses exert an "antiaging" action, leading to changes in life span, age-related pathology, and physiological function as predicted by the oxidative stress theory of aging.
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Affiliation(s)
- Adam B Salmon
- The Sam and Ann Barshop Institute for Longevity and Aging Studies, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
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161
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Bonda DJ, Wang X, Gustaw-Rothenberg KA, Perry G, Smith MA, Zhu X. Mitochondrial Drugs for Alzheimer Disease. Pharmaceuticals (Basel) 2009; 2:287-298. [PMID: 20657666 PMCID: PMC2909133 DOI: 10.3390/ph2030287] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Therapeutic strategies for Alzheimer disease (AD) have yet to offer a disease-modifying effect to stop the debilitating progression of neurodegeneration and cognitive decline. Rather, treatments thus far are limited to agents that slow disease progression without halting it, and although much work towards a cure is underway, a greater understanding of disease etiology is certainly necessary for any such achievement. Mitochondria, as the centers of cellular metabolic activity and the primary generators of reactive oxidative species in the cell, received particular attention especially given that mitochondrial defects are known to contribute to cellular damage. Furthermore, as oxidative stress has come to the forefront of AD as a causal theory, and as mitochondrial damage is known to precede much of the hallmark pathologies of AD, it seems increasingly apparent that this metabolic organelle is ultimately responsible for much, if not all of disease pathogenesis. In this review, we review the role of neuronal mitochondria in the pathogenesis of AD and critically assess treatment strategies that utilize this upstream access point as a method for disease prevention. We suspect that, with a revived focus on mitochondrial repair and protection, an effective and realistic therapeutic agent can be successfully developed.
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Affiliation(s)
- David J. Bonda
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Xinglong Wang
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Katarzyna A. Gustaw-Rothenberg
- Memory and Cognition Center, University Hospitals Case Medical Center, Beachwood, OH 44122, USA
- Department of Neurodegenerative Diseases, Institute of Agricultural Medicine, Lublin, Poland
| | - George Perry
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
- UTSA Neurosciences Institute and Department of Biology, College of Sciences, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Mark A. Smith
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Xiongwei Zhu
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
- Author to whom correspondence should be addressed; ; Tel.: +1-216-368-5903; Fax: +1-216-368-8964
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162
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Dumont M, Ho DJ, Calingasan NY, Xu H, Gibson G, Beal MF. Mitochondrial dihydrolipoyl succinyltransferase deficiency accelerates amyloid pathology and memory deficit in a transgenic mouse model of amyloid deposition. Free Radic Biol Med 2009; 47:1019-27. [PMID: 19596066 PMCID: PMC2761144 DOI: 10.1016/j.freeradbiomed.2009.07.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Revised: 07/06/2009] [Accepted: 07/07/2009] [Indexed: 12/20/2022]
Abstract
Mitochondrial dysfunction and oxidative stress are involved in Alzheimer disease (AD) pathogenesis. In human AD brains, the activity of the alpha-ketoglutarate dehydrogenase enzyme complex (alpha-KGDHC) is reduced. KGDHC is mostly involved in NADH production. It can also participate in oxidative stress and reactive oxygen species (ROS) production. The mitochondrial dihydrolipoyl succinyltransferase enzyme (DLST) is a key subunit specific to the alpha-KGDHC. In cultured cells, reduction of DLST increased H(2)O(2)-induced ROS generation and cell death. Thus, we asked whether partial genetic deletion of DLST could accelerate the onset of AD pathogenesis, using a transgenic mouse model of amyloid deposition crossed with DLST(+/-) mice. Tg19959 mice, which carry the human amyloid precursor protein with two mutations, develop amyloid deposits and progressive behavioral abnormalities. We compared Tg19959 mice to Tg19959-DLST(+/-) littermates at 2-3 months of age and studied the effects of DLST deficiency on amyloid deposition, spatial learning and memory, and oxidative stress. We found that alpha-KGDHC activity was reduced in DLST(+/-) mice. We also found that DLST deficiency increased amyloid plaque burden, Abeta oligomers, and nitrotyrosine levels and accelerated the occurrence of spatial learning and memory deficits in female Tg19959 mice. Our data suggest that alpha-KGDHC may be involved in AD pathogenesis through increased mitochondrial oxidative stress.
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Affiliation(s)
- Magali Dumont
- Department of Neurology and Neuroscience, Weill Cornell Medical College,New York, NY 10065, USA.
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163
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Massaad CA, Pautler RG, Klann E. Mitochondrial superoxide: a key player in Alzheimer's disease. Aging (Albany NY) 2009; 1:758-61. [PMID: 20157564 PMCID: PMC2815734 DOI: 10.18632/aging.100088] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Accepted: 09/14/2009] [Indexed: 12/25/2022]
Affiliation(s)
- Cynthia A Massaad
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA.
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164
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Zhang X, Liu Y, Feng C, Yang S, Wang Y, Wu AS, Yue Y. Proteomic profiling of the insoluble fractions in the rat hippocampus post-propofol anesthesia. Neurosci Lett 2009; 465:165-70. [PMID: 19682543 DOI: 10.1016/j.neulet.2009.08.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2009] [Revised: 08/04/2009] [Accepted: 08/08/2009] [Indexed: 12/17/2022]
Abstract
Cognitive dysfunction after propofol anesthesia has been previously found. The underlying mechanisms of this sequel remain unclear. Insoluble proteins as major targets of anesthetics participated in various pathophysiological processes. This study aimed to provide evidence that changes in insoluble proteome in rat hippocampus may be involved in molecular mechanism of cognitive dysfunction following propofol anesthesia. Proteins extracted from rat hippocampus were separated by two-dimensional electrophoresis (2-DE). Their expression patterns were observed at 1, 6, 24 h and 7 days after 3 h of propofol anesthesia. Differentially expressed protein spots among groups were submitted to matrix-assisted laser desorption/ionization time of flight mass spectrometer (MALDI-TOF MS) assay and peptide mass fingerprinting (PMF) identification. Identified proteins were further analyzed through Gene Ontology (GO). Results of 2-DE were selectively assayed using Western blot and RT-PCR. Fifty-nine differentially expressed proteins were detected, among which 43 were identified through MALDI-TOF MS. Most identified proteins were distributed in organelles and membranes. According to biological process category, 27 proteins were involved in metabolic process, 19 in developmental process, 14 in stimulus-response, and 21 in biological regulation. Most changes took place within 24 h, with more down-regulation within 6 h. Twelve proteins did not restore to the basic level until the 7th day after propofol anesthesia. Expressions of insoluble proteome dynamically changed following propofol anesthesia. Down-regulations at early stage might produce depressive effects, which may be involved in molecular mechanism of cognitive dysfunction after propofol anesthesia.
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Affiliation(s)
- Xuena Zhang
- Department of Anaesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, PR China
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165
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Deletion of the alpha 7 nicotinic acetylcholine receptor gene improves cognitive deficits and synaptic pathology in a mouse model of Alzheimer's disease. J Neurosci 2009; 29:8805-15. [PMID: 19587288 DOI: 10.1523/jneurosci.6159-08.2009] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
It has been recently shown that the Alzheimer's disease (AD) pathogenic peptide amyloid beta(1-42) (Abeta(1-42)) binds to the alpha7 nicotinic acetylcholine receptor (alpha7nAChR) with high affinity and the alpha7nAChR and Abeta(1-42) are both found colocalized in neuritic plaques of human brains with AD. Moreover, the intraneuronal accumulation of Abeta(1-42) was shown to be facilitated by its high-affinity binding to the alpha7nAChR, and alpha7nAChR activation mediates Abeta-induced tau protein phosphorylation. To test the hypothesis that alpha7nAChRs are involved in AD pathogenesis, we used a transgenic mouse model of AD overexpressing a mutated form of the human amyloid precursor protein (APP) and lacking the alpha7nAChR gene (APPalpha7KO). We have shown that, despite the presence of high amounts of APP and amyloid deposits, deleting the alpha7nAChR subunit in the mouse model of AD leads to a protection from the dysfunction in synaptic integrity (pathology and plasticity) and learning and memory behavior. Specifically, APPalpha7KO mice express APP and Abeta at levels similar to APP mice, and yet they were able to solve a cognitive challenge such as the Morris water maze test significantly better than APP, with performances comparable to control groups. Moreover, deleting the alpha7nAChR subunit protected the brain from loss of the synaptic markers synaptophysin and MAP2, reduced the gliosis, and preserved the capacity to elicit long-term potentiation otherwise deficient in APP mice. These results are consistent with the hypothesis that the alpha7nAChR plays a role in AD and suggest that interrupting alpha7nAChR function could be beneficial in the treatment of AD.
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166
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Overexpression of SOD-2 reduces hippocampal superoxide and prevents memory deficits in a mouse model of Alzheimer's disease. Proc Natl Acad Sci U S A 2009; 106:13576-81. [PMID: 19666610 DOI: 10.1073/pnas.0902714106] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease characterized by impaired cognitive function and the deposition of extracellular amyloid plaques and intracellular tangles. Although the proximal cause of AD is not well understood, it is clear that amyloid-beta (Abeta) plays a critical role in AD pathology. Recent studies also implicate mitochondrial abnormalities in AD. We investigated this idea by crossing mice that overexpress mitochondrial superoxide dismutase (SOD-2) with the Tg2576 mouse model of AD that overexpresses the human amyloid precursor protein carrying the Swedish mutation (K670N:M671L). We found that overexpression of SOD-2 decreased hippocampal superoxide, prevented AD-related learning and memory deficits, and reduced Abeta plaques. Interestingly, SOD-2 overexpression did not affect the absolute levels of Abeta(1-40) and Abeta(1-42), but did significantly reduce the Abeta(1-42) to Abeta(1-40) ratio, thereby shifting the balance toward a less amyloidogenic Abeta composition. These findings directly link mitochondrial superoxide to AD pathology and demonstrate the beneficial effects of a mitochondrial anti-oxidant enzyme, hence offering significant therapeutic implications for AD.
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167
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Valdivia A, Pérez-Álvarez S, Aroca-Aguilar JD, Ikuta I, Jordán J. Superoxide dismutases: a physiopharmacological update. J Physiol Biochem 2009; 65:195-208. [DOI: 10.1007/bf03179070] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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168
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Zawia NH, Lahiri DK, Cardozo-Pelaez F. Epigenetics, oxidative stress, and Alzheimer disease. Free Radic Biol Med 2009; 46:1241-9. [PMID: 19245828 PMCID: PMC2673453 DOI: 10.1016/j.freeradbiomed.2009.02.006] [Citation(s) in RCA: 229] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 01/28/2009] [Accepted: 02/09/2009] [Indexed: 11/20/2022]
Abstract
Alzheimer disease (AD) is a progressive neurodegenerative disorder whose clinical manifestations appear in old age. The sporadic nature of 90% of AD cases, the differential susceptibility to and course of the illness, as well as the late age onset of the disease suggest that epigenetic and environmental components play a role in the etiology of late-onset AD. Animal exposure studies demonstrated that AD may begin early in life and may involve an interplay between the environment, epigenetics, and oxidative stress. Early life exposure of rodents and primates to the xenobiotic metal lead (Pb) enhanced the expression of genes associated with AD, repressed the expression of others, and increased the burden of oxidative DNA damage in the aged brain. Epigenetic mechanisms that control gene expression and promote the accumulation of oxidative DNA damage are mediated through alterations in the methylation or oxidation of CpG dinucleotides. We found that environmental influences occurring during brain development inhibit DNA-methyltransferases, thus hypomethylating promoters of genes associated with AD such as the beta-amyloid precursor protein (APP). This early life imprint was sustained and triggered later in life to increase the levels of APP and amyloid-beta (Abeta). Increased Abeta levels promoted the production of reactive oxygen species, which damage DNA and accelerate neurodegenerative events. Whereas AD-associated genes were overexpressed late in life, others were repressed, suggesting that these early life perturbations result in hypomethylation as well as hypermethylation of genes. The hypermethylated genes are rendered susceptible to Abeta-enhanced oxidative DNA damage because methylcytosines restrict repair of adjacent hydroxyguanosines. Although the conditions leading to early life hypo- or hypermethylation of specific genes are not known, these changes can have an impact on gene expression and imprint susceptibility to oxidative DNA damage in the aged brain.
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Affiliation(s)
- Nasser H Zawia
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881, USA.
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169
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Mattson MP, Gleichmann M, Cheng A. Mitochondria in neuroplasticity and neurological disorders. Neuron 2009; 60:748-66. [PMID: 19081372 DOI: 10.1016/j.neuron.2008.10.010] [Citation(s) in RCA: 766] [Impact Index Per Article: 51.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 09/29/2008] [Accepted: 10/03/2008] [Indexed: 12/12/2022]
Abstract
Mitochondrial electron transport generates the ATP that is essential for the excitability and survival of neurons, and the protein phosphorylation reactions that mediate synaptic signaling and related long-term changes in neuronal structure and function. Mitochondria are highly dynamic organelles that divide, fuse, and move purposefully within axons and dendrites. Major functions of mitochondria in neurons include the regulation of Ca(2+) and redox signaling, developmental and synaptic plasticity, and the arbitration of cell survival and death. The importance of mitochondria in neurons is evident in the neurological phenotypes in rare diseases caused by mutations in mitochondrial genes. Mitochondria-mediated oxidative stress, perturbed Ca(2+) homeostasis, and apoptosis may also contribute to the pathogenesis of prominent neurological diseases including Alzheimer's, Parkinson's, and Huntington's diseases; stroke; amyotrophic lateral sclerosis; and psychiatric disorders. Advances in understanding the molecular and cell biology of mitochondria are leading to novel approaches for the prevention and treatment of neurological disorders.
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Affiliation(s)
- Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, USA.
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170
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Dumont M, Wille E, Stack C, Calingasan NY, Beal MF, Lin MT. Reduction of oxidative stress, amyloid deposition, and memory deficit by manganese superoxide dismutase overexpression in a transgenic mouse model of Alzheimer's disease. FASEB J 2009; 23:2459-66. [PMID: 19346295 DOI: 10.1096/fj.09-132928] [Citation(s) in RCA: 173] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In Alzheimer's disease (AD), oxidative stress is present early and contributes to disease pathogenesis. We previously reported that in Tg19959 transgenic AD mice, partial deficiency of the mitochondrial antioxidant enzyme manganese superoxide dismutase (MnSOD) exacerbated amyloid pathology. We therefore asked whether MnSOD overexpression would prove beneficial against AD pathogenesis, by studying the offspring of Tg19959 mice crossed with MnSOD-overexpressing mice. At 4 mo of age, there was a 2- to 3-fold increase in MnSOD protein levels in Tg19959-MnSOD mice compared to Tg19959 littermates. Tg19959-MnSOD mice also had a 50% increase in catalase protein levels, a 50% decrease in levels of oxidized protein, and a 33% reduction in cortical plaque burden compared to Tg19959 littermates. Spatial memory was impaired and synaptophysin levels were decreased in Tg19959 mice compared to wild-type littermates, but memory and synaptophysin levels were restored to wild-type levels in Tg19959-MnSOD littermates. These benefits occurred without changes in sodium dodecyl sulfate-soluble or formic acid-soluble Abeta pools or Abeta oligomers in Tg19959-MnSOD mice compared to Tg19959 littermates. These data demonstrate that facilitation of the mitochondrial antioxidant response improves resistance to Abeta, slows plaque formation or increases plaque degradation, and markedly attenuates the phenotype in a transgenic AD mouse model.
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Affiliation(s)
- Magali Dumont
- Weill Cornell Medical College, Department of Neurology and Neuroscience, 525 E. 68th St., New York, NY 10065, USA
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171
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Dumont M, Wille E, Calingasan NY, Tampellini D, Williams C, Gouras GK, Liby K, Sporn M, Beal MF, Lin MT. Triterpenoid CDDO-methylamide improves memory and decreases amyloid plaques in a transgenic mouse model of Alzheimer's disease. J Neurochem 2009; 109:502-12. [PMID: 19200343 PMCID: PMC3083825 DOI: 10.1111/j.1471-4159.2009.05970.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Oxidative stress is one of the earliest events in the pathogenesis of Alzheimer's disease (AD) and can markedly exacerbate amyloid pathology. Modulation of antioxidant and anti-inflammatory pathways represents an important approach for AD therapy. Synthetic triterpenoids have been found to facilitate antioxidant response and reduce inflammation in several models. We investigated the effect of the triterpenoid, 2-Cyano-3,12-Dioxooleana-1,9-Dien-28-Oic acid-MethylAmide (CDDO-MA) in Tg19959 mice, which carry the human amyloid precursor protein with two mutations. These mice develop memory impairments and amyloid plaques as early as 2-3 months of age. CDDO-MA was provided with chow (800 mg/kg) from 1 to 4 months of age. CDDO-MA significantly improved spatial memory retention and reduced plaque burden, Abeta42 levels, microgliosis, and oxidative stress in Tg19959 mice.
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Affiliation(s)
- Magali Dumont
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, New York, USA
| | - Elizabeth Wille
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, New York, USA
| | - Noel Y. Calingasan
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, New York, USA
| | - Davide Tampellini
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, New York, USA
| | - Charlotte Williams
- Department of Pharmacology and Toxicology, Dartmouth Medical School, Hanover, New Hampshire, USA
| | - Gunnar K. Gouras
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, New York, USA
| | - Karen Liby
- Department of Pharmacology and Toxicology, Dartmouth Medical School, Hanover, New Hampshire, USA
| | - Michael Sporn
- Department of Pharmacology and Toxicology, Dartmouth Medical School, Hanover, New Hampshire, USA
| | - M. Flint Beal
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, New York, USA
| | - Michael T. Lin
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, New York, USA
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172
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Hortells P, Monleón E, Acín C, Vargas A, Vasseur V, Salomon A, Ryffel B, Cesbron JY, Badiola JJ, Monzón M. The Effect of Metal Imbalances on Scrapie Neurodegeneration. Zoonoses Public Health 2009; 57:358-66. [DOI: 10.1111/j.1863-2378.2009.01230.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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173
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Herring A, Blome M, Ambrée O, Sachser N, Paulus W, Keyvani K. Reduction of cerebral oxidative stress following environmental enrichment in mice with Alzheimer-like pathology. Brain Pathol 2009; 20:166-75. [PMID: 19134003 DOI: 10.1111/j.1750-3639.2008.00257.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Oxidative stress is a key feature during progression of chronic neurodegenerative conditions such as Alzheimer's disease. In aging humans and animals, voluntary exercise lowers oxidative stress reactions. Additionally, recent work in our lab demonstrated that cognitive and physical stimulation (termed environmental enrichment) counteracts amyloid beta pathology, neurovascular dysfunction and behavioral symptoms in mice with Alzheimer-like disease. Based on these facts, we hypothesized that cognitive and physical activity can also protect against oxidative stress in Alzheimer-diseased brain. We, therefore, kept female TgCRND8 mice under standard and enriched housing from day 30 until 5 months of age. Environmental stimulation attenuated pro-oxidative processes and triggered anti-oxidative defense mechanisms as indicated by diminished biomarkers for reactive oxygen and nitrogen species, downregulation of pro-inflammatory and pro-oxidative mediators, decreased expression of pro-apoptotic caspases, and upregulation of SOD1 and SOD2. This study identifies a thus far undescribed antagonizing effect of environmental stimulation on Alzheimer's disease-related oxidative damage.
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Affiliation(s)
- Arne Herring
- Institute of Neuropathology, University Hospital, Muenster, Germany
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174
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Röhl C, Armbrust E, Kolbe K, Lucius R, Maser E, Venz S, Gülden M. Activated microglia modulate astroglial enzymes involved in oxidative and inflammatory stress and increase the resistance of astrocytes to oxidative stress in vitro. Glia 2008; 56:1114-26. [PMID: 18442093 DOI: 10.1002/glia.20683] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Neuropathological processes in the central nervous system are commonly accompanied by an activation of microglia and astrocytes. The involvement of both cell populations in the onset and progress of neurological disorders has been widely documented, implicating both beneficial and detrimental influences on the neural tissue. Nevertheless, little is known about the interplay of these glial cell populations, especially under diseased conditions. To examine the effects of activated microglia on astrocytes purified rat astroglial cell cultures were treated with medium conditioned by purified quiescent (MCM[-]) or lipopolysaccharide (LPS)-activated rat microglia (MCM[+]) and subjected to a comparative proteome analysis based on two-dimensional gel electrophoresis. No significant down regulation of proteins was observed. The majority of the 19 proteins identified by means of nano HPLC/ESI-MS/MS in the 12 most prominent protein spots significantly overexpressed (> or =2-fold) in MCM[+] treated astrocytes are involved in inflammatory processes and oxidative stress response: superoxide dismutases (Sod), peroxiredoxins, glutathione S-transferases (Gst), nucleoside diphosphate kinase B, argininosuccinate synthase (Ass), and cellular retinol-binding protein I (Rbp1). Sod2, Rbp1, Gstp1, and Ass were also significantly increased on the mRNA level determined by quantitative RT-PCR. The upregulation of antioxidative enzymes in astrocytes was accompanied by a higher resistance to oxidative stress induced by H2O2. These results show that activated microglia change the expression of antioxidative proteins in astrocytes and protect them against oxidative stress, which might be an effective way to increase the neuroprotective potential of astrocytes under pathological conditions associated with oxidative stress and inflammation.
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Affiliation(s)
- Claudia Röhl
- Department of Anatomy, University of Kiel, Olshausenstr. 40, D-24098 Kiel, Germany.
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175
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Ranganathan S, Harmison GG, Meyertholen K, Pennuto M, Burnett BG, Fischbeck KH. Mitochondrial abnormalities in spinal and bulbar muscular atrophy. Hum Mol Genet 2008; 18:27-42. [PMID: 18824496 PMCID: PMC2644643 DOI: 10.1093/hmg/ddn310] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Spinal and bulbar muscular atrophy (SBMA) is a motor neuron disease caused by polyglutamine expansion mutation in the androgen receptor (AR). We investigated whether the mutant protein alters mitochondrial function. We found that constitutive and doxycycline-induced expression of the mutant AR in MN-1 and PC12 cells, respectively, are associated with depolarization of the mitochondrial membrane. This was mitigated by cyclosporine A, which inhibits opening of the mitochondrial permeability transition pore. We also found that the expression of the mutant protein in the presence of ligand results in an elevated level of reactive oxygen species, which is blocked by the treatment with the antioxidants co-enzyme Q10 and idebenone. The mutant protein in MN-1 cells also resulted in increased Bax, caspase 9 and caspase 3. We assessed the effects of mutant AR on the transcription of mitochondrial proteins and found altered expression of the peroxisome proliferator-activated receptor γ coactivator 1 and the mitochondrial specific antioxidant superoxide dismutase-2 in affected tissues of SBMA knock-in mice. In addition, we found that the AR associates with mitochondria in cultured cells. This study thus provides evidence for mitochondrial dysfunction in SBMA cell and animal models, either through indirect effects on the transcription of nuclear-encoded mitochondrial genes or through direct effects of the mutant protein on mitochondria or both. These findings indicate possible benefit from mitochondrial therapy for SBMA.
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Affiliation(s)
- Srikanth Ranganathan
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
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176
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Cyclophilin D deficiency attenuates mitochondrial and neuronal perturbation and ameliorates learning and memory in Alzheimer's disease. Nat Med 2008; 14:1097-105. [PMID: 18806802 DOI: 10.1038/nm.1868] [Citation(s) in RCA: 723] [Impact Index Per Article: 45.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2008] [Accepted: 08/25/2008] [Indexed: 12/22/2022]
Abstract
Cyclophilin D (CypD, encoded by Ppif) is an integral part of the mitochondrial permeability transition pore, whose opening leads to cell death. Here we show that interaction of CypD with mitochondrial amyloid-beta protein (Abeta) potentiates mitochondrial, neuronal and synaptic stress. The CypD-deficient cortical mitochondria are resistant to Abeta- and Ca(2+)-induced mitochondrial swelling and permeability transition. Additionally, they have an increased calcium buffering capacity and generate fewer mitochondrial reactive oxygen species. Furthermore, the absence of CypD protects neurons from Abeta- and oxidative stress-induced cell death. Notably, CypD deficiency substantially improves learning and memory and synaptic function in an Alzheimer's disease mouse model and alleviates Abeta-mediated reduction of long-term potentiation. Thus, the CypD-mediated mitochondrial permeability transition pore is directly linked to the cellular and synaptic perturbations observed in the pathogenesis of Alzheimer's disease. Blockade of CypD may be a therapeutic strategy in Alzheimer's disease.
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177
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Hortells P, Monleón E, Acín C, Vargas A, Ryffel B, Cesbron JY, Badiola JJ, Monzón M. Effect of the dimethoate administration on a Scrapie murine model. Zoonoses Public Health 2008; 55:368-75. [PMID: 18667030 DOI: 10.1111/j.1863-2378.2008.01139.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Some authors have associated organophosphate compounds with susceptibility to transmissible spongiform encephalopathy (TSE) and even with the origin of this group of diseases. Nevertheless, the actual role played by these compounds still remains unclear. The aim of this study was to assess the effect of oral exposure to dimethoate (DMT) on the development of Scrapie using a genetically modified murine model. A total of 70 C57BL/6 mice over-expressing the PrP gene (Tg20) were included in the present study. A portion of the mice were intraperitoneally inoculated, while the rest were maintained as non-infected controls. Animals from the treated group were exposed to dimethoate dissolved in drinking water from the beginning of the experiment. Variables of incubation period, spongiosis, PrPsc deposits, glial over-expression, neuronal loss, and amyloid plaques were assessed in all animals. According to the results, a treatment consisting of a daily 15 mg/kg dose of DMT for 5 weeks did not show any effect on any of the variables assessed. Although more exhaustive studies for assessing different doses and organic compounds are required, this finding constitutes an empirical study that rules out the possibility that this compound may have a predisposing effect on TSEs.
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Affiliation(s)
- P Hortells
- Research Centre for Prion Diseases, Faculty of Veterinary, University of Zaragoza, Zaragoza, Spain
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178
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Metals in Alzheimer's and Parkinson's diseases. Curr Opin Chem Biol 2008; 12:222-8. [PMID: 18342639 DOI: 10.1016/j.cbpa.2008.02.019] [Citation(s) in RCA: 569] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2008] [Revised: 02/04/2008] [Accepted: 02/17/2008] [Indexed: 12/31/2022]
Abstract
There has been steadily growing interest in the participation of metal ions (especially, zinc, copper, and iron) in neurobiological processes, such as the regulation of synaptic transmission. Recent descriptions of the release of zinc and copper in the cortical glutamatergic synapse, and influencing the response of the NMDA receptor underscore the relevance of understanding the inorganic milieu of the synapse to neuroscience. Additionally, major neurodegenerative disorders, including Alzheimer's disease and Parkinson's disease, are characterized by elevated tissue iron, and miscompartmentalization of copper and zinc (e.g. accumulation in amyloid). Increasingly sophisticated medicinal chemistry approaches, which correct these metal abnormalities without causing systemic disturbance of these essential minerals, are being tested. These small molecules show promise of being disease-modifying.
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179
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Scearce-Levie K, Roberson ED, Gerstein H, Cholfin JA, Mandiyan VS, Shah NM, Rubenstein JLR, Mucke L. Abnormal social behaviors in mice lacking Fgf17. GENES BRAIN AND BEHAVIOR 2008; 7:344-54. [PMID: 17908176 DOI: 10.1111/j.1601-183x.2007.00357.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The fibroblast growth factor family of secreted signaling molecules is essential for patterning in the central nervous system. Fibroblast growth factor 17 (Fgf17) has been shown to contribute to regionalization of the rodent frontal cortex. To determine how Fgf17 signaling modulates behavior, both during development and in adulthood, we studied mice lacking one or two copies of the Fgf17 gene. Fgf17-deficient mice showed no abnormalities in overall physical growth, activity level, exploration, anxiety-like behaviors, motor co-ordination, motor learning, acoustic startle, prepulse inhibition, feeding, fear conditioning, aggression and olfactory exploration. However, they displayed striking deficits in several behaviors involving specific social interactions. Fgf17-deficient pups vocalized less than wild-type controls when separated from their mother and siblings. Elimination of Fgf17 also decreased the interaction of adult males with a novel ovariectomized female in a social recognition test and reduced the amount of time opposite-sex pairs spent engaged in prolonged, affiliative interactions during exploration of a novel environment. After social exploration of a novel environment, Fgf17-deficient mice showed less activation of the immediate-early gene Fos in the frontal cortex than wild-type controls. Our findings show that Fgf17 is required for several complex social behaviors and suggest that disturbances in Fgf17 signaling may contribute to neuropsychiatric diseases that affect such behaviors.
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Affiliation(s)
- K Scearce-Levie
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158-2261, USA.
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180
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Sompol P, Ittarat W, Tangpong J, Chen Y, Doubinskaia I, Batinic-Haberle I, Abdul HM, Butterfield DA, St Clair DK. A neuronal model of Alzheimer's disease: an insight into the mechanisms of oxidative stress-mediated mitochondrial injury. Neuroscience 2008; 153:120-30. [PMID: 18353561 DOI: 10.1016/j.neuroscience.2008.01.044] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2007] [Revised: 01/23/2008] [Accepted: 01/27/2008] [Indexed: 12/31/2022]
Abstract
Alzheimer's disease (AD) is associated with beta-amyloid accumulation, oxidative stress and mitochondrial dysfunction. However, the effects of genetic mutation of AD on oxidative status and mitochondrial manganese superoxide dismutase (MnSOD) production during neuronal development are unclear. To investigate the consequences of genetic mutation of AD on oxidative damages and production of MnSOD during neuronal development, we used primary neurons from new born wild-type (WT/WT) and amyloid precursor protein (APP) (NLh/NLh) and presenilin 1 (PS1) (P264L) knock-in mice (APP/PS1) which incorporated humanized mutations in the genome. Increasing levels of oxidative damages, including protein carbonyl, 4-hydroxynonenal (4-HNE) and 3-nitrotyrosine (3-NT), were accompanied by a reduction in mitochondrial membrane potential in both developing and mature APP/PS1 neurons compared with WT/WT neurons suggesting mitochondrial dysfunction under oxidative stress. Interestingly, developing APP/PS1 neurons were significantly more resistant to beta-amyloid 1-42 treatment, whereas mature APP/PS1 neurons were more vulnerable than WT/WT neurons of the same age. Consistent with the protective function of MnSOD, developing APP/PS1 neurons have increased MnSOD protein and activity, indicating an adaptive response to oxidative stress in developing neurons. In contrast, mature APP/PS1 neurons exhibited lower MnSOD levels compared with mature WT/WT neurons indicating that mature APP/PS1 neurons lost the adaptive response. Moreover, mature APP/PS1 neurons had more co-localization of MnSOD with nitrotyrosine indicating a greater inhibition of MnSOD by nitrotyrosine. Overexpression of MnSOD or addition of MnTE-2-PyP(5+) (SOD mimetic) protected against beta-amyloid-induced neuronal death and improved mitochondrial respiratory function. Together, the results demonstrate that compensatory induction of MnSOD in response to an early increase in oxidative stress protects developing neurons against beta-amyloid toxicity. However, continuing development of neurons under oxidative damage conditions may suppress the expression of MnSOD and enhance cell death in mature neurons.
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Affiliation(s)
- P Sompol
- Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536, USA
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181
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Alzheimer's disease (AD)-like pathology in aged monkeys after infantile exposure to environmental metal lead (Pb): evidence for a developmental origin and environmental link for AD. J Neurosci 2008; 28:3-9. [PMID: 18171917 DOI: 10.1523/jneurosci.4405-07.2008] [Citation(s) in RCA: 316] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The sporadic nature of Alzheimer's disease (AD) argues for an environmental link that may drive AD pathogenesis; however, the triggering factors and the period of their action are unknown. Recent studies in rodents have shown that exposure to lead (Pb) during brain development predetermined the expression and regulation of the amyloid precursor protein (APP) and its amyloidogenic beta-amyloid (Abeta) product in old age. Here, we report that the expression of AD-related genes [APP, BACE1 (beta-site APP cleaving enzyme 1)] as well as their transcriptional regulator (Sp1) were elevated in aged (23-year-old) monkeys exposed to Pb as infants. Furthermore, developmental exposure to Pb altered the levels, characteristics, and intracellular distribution of Abeta staining and amyloid plaques in the frontal association cortex. These latent effects were accompanied by a decrease in DNA methyltransferase activity and higher levels of oxidative damage to DNA, indicating that epigenetic imprinting in early life influenced the expression of AD-related genes and promoted DNA damage and pathogenesis. These data suggest that AD pathogenesis is influenced by early life exposures and argue for both an environmental trigger and a developmental origin of AD.
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182
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Nox2-derived radicals contribute to neurovascular and behavioral dysfunction in mice overexpressing the amyloid precursor protein. Proc Natl Acad Sci U S A 2008; 105:1347-52. [PMID: 18202172 DOI: 10.1073/pnas.0711568105] [Citation(s) in RCA: 266] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Alterations in cerebrovascular regulation related to vascular oxidative stress have been implicated in the mechanisms of Alzheimer's disease (AD), but their role in the amyloid deposition and cognitive impairment associated with AD remains unclear. We used mice overexpressing the Swedish mutation of the amyloid precursor protein (Tg2576) as a model of AD to examine the role of reactive oxygen species produced by NADPH oxidase in the cerebrovascular alterations, amyloid deposition, and behavioral deficits observed in these mice. We found that 12- to 15-month-old Tg2576 mice lacking the catalytic subunit Nox2 of NADPH oxidase do not develop oxidative stress, cerebrovascular dysfunction, or behavioral deficits. These improvements occurred without reductions in brain amyloid-beta peptide (Abeta) levels or amyloid plaques. The findings unveil a previously unrecognized role of Nox2-derived radicals in the behavioral deficits of Tg2576 mice and provide a link between the neurovascular dysfunction and cognitive decline associated with amyloid pathology.
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183
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Duyckaerts C, Potier MC, Delatour B. Alzheimer disease models and human neuropathology: similarities and differences. Acta Neuropathol 2008; 115:5-38. [PMID: 18038275 PMCID: PMC2100431 DOI: 10.1007/s00401-007-0312-8] [Citation(s) in RCA: 276] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2007] [Revised: 10/13/2007] [Accepted: 10/14/2007] [Indexed: 12/02/2022]
Abstract
Animal models aim to replicate the symptoms, the lesions or the cause(s) of Alzheimer disease. Numerous mouse transgenic lines have now succeeded in partially reproducing its lesions: the extracellular deposits of Abeta peptide and the intracellular accumulation of tau protein. Mutated human APP transgenes result in the deposition of Abeta peptide, similar but not identical to the Abeta peptide of human senile plaque. Amyloid angiopathy is common. Besides the deposition of Abeta, axon dystrophy and alteration of dendrites have been observed. All of the mutations cause an increase in Abeta 42 levels, except for the Arctic mutation, which alters the Abeta sequence itself. Overexpressing wild-type APP alone (as in the murine models of human trisomy 21) causes no Abeta deposition in most mouse lines. Doubly (APP x mutated PS1) transgenic mice develop the lesions earlier. Transgenic mice in which BACE1 has been knocked out or overexpressed have been produced, as well as lines with altered expression of neprilysin, the main degrading enzyme of Abeta. The APP transgenic mice have raised new questions concerning the mechanisms of neuronal loss, the accumulation of Abeta in the cell body of the neurons, inflammation and gliosis, and the dendritic alterations. They have allowed some insight to be gained into the kinetics of the changes. The connection between the symptoms, the lesions and the increase in Abeta oligomers has been found to be difficult to unravel. Neurofibrillary tangles are only found in mouse lines that overexpress mutated tau or human tau on a murine tau -/- background. A triply transgenic model (mutated APP, PS1 and tau) recapitulates the alterations seen in AD but its physiological relevance may be discussed. A number of modulators of Abeta or of tau accumulation have been tested. A transgenic model may be analyzed at three levels at least (symptoms, lesions, cause of the disease), and a reading key is proposed to summarize this analysis.
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Affiliation(s)
- Charles Duyckaerts
- Laboratoire de Neuropathologie Raymond Escourolle, Hôpital de La Salpêtrière, 47 Boulevard de l'Hôpital, 75651, Paris Cedex 13, France.
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184
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Sharma S, Sud N, Wiseman DA, Carter AL, Kumar S, Hou Y, Rau T, Wilham J, Harmon C, Oishi P, Fineman JR, Black SM. Altered carnitine homeostasis is associated with decreased mitochondrial function and altered nitric oxide signaling in lambs with pulmonary hypertension. Am J Physiol Lung Cell Mol Physiol 2007; 294:L46-56. [PMID: 18024721 DOI: 10.1152/ajplung.00247.2007] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Utilizing aortopulmonary vascular graft placement in the fetal lamb, we have developed a model (shunt) of pulmonary hypertension that mimics congenital heart disease with increased pulmonary blood flow. Our previous studies have identified a progressive development of endothelial dysfunction in shunt lambs that is dependent, at least in part, on decreased nitric oxide (NO) signaling. The purpose of this study was to evaluate the possible role of a disruption in carnitine metabolism in shunt lambs and to determine the effect on NO signaling. Our data indicate that at 2 wk of age, shunt lambs have significantly reduced expression (P < 0.05) of the key enzymes in carnitine metabolism: carnitine palmitoyltransferases 1 and 2 as well as carnitine acetyltransferase (CrAT). In addition, we found that CrAT activity was inhibited due to increased nitration. Furthermore, free carnitine levels were significantly decreased whereas acylcarnitine levels were significantly higher in shunt lambs (P < 0.05). We also found that alterations in carnitine metabolism resulted in mitochondrial dysfunction, since shunt lambs had significantly decreased pyruvate, increased lactate, and a reduced pyruvate/lactate ratio. In pulmonary arterial endothelial cells cultured from juvenile lambs, we found that mild uncoupling of the mitochondria led to a decrease in cellular ATP levels and a reduction in both endothelial NO synthase-heat shock protein 90 (eNOS-HSP90) interactions and NO signaling. Similarly, in shunt lambs we found a loss of eNOS-HSP90 interactions that correlated with a progressive decrease in NO signaling. Our data suggest that mitochondrial dysfunction may play a role in the development of endothelial dysfunction and pulmonary hypertension and increased pulmonary blood flow.
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Affiliation(s)
- Shruti Sharma
- Program in Pulmonary Disease, Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912, USA
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185
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Reduced mitochondrial SOD displays mortality characteristics reminiscent of natural aging. Mech Ageing Dev 2007; 128:706-16. [PMID: 18078670 DOI: 10.1016/j.mad.2007.10.013] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Revised: 10/12/2007] [Accepted: 10/24/2007] [Indexed: 12/15/2022]
Abstract
Manganese superoxide dismutase (MnSOD or SOD2) is a key mitochondrial enzymatic antioxidant. Arguably the most striking phenotype associated with complete loss of SOD2 in flies and mice is shortened life span. To further explore the role of SOD2 in protecting animals from aging and age-associated pathology, we generated a unique collection of Drosophila mutants that progressively reduce SOD2 expression and function. Mitochondrial aconitase activity was substantially reduced in the Sod2 mutants, suggesting that SOD2 normally ensures the functional capacity of mitochondria. Flies with severe reductions in SOD2 expression exhibited accelerated senescence of olfactory behavior as well as precocious neurodegeneration and DNA strand breakage in neurons. Furthermore, life span was progressively shortened and age-dependent mortality was increased in conjunction with reduced SOD2 expression, while initial mortality and developmental viability were unaffected. Interestingly, life span and age-dependent mortality varied exponentially with SOD2 activity, indicating that there might normally be a surplus of this enzyme for protecting animals from premature death. Our data support a model in which disruption of the protective effects of SOD2 on mitochondria manifests as profound changes in behavioral and demographic aging as well as exacerbated age-related pathology in the nervous system.
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186
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Maloney MT, Bamburg JR. Cofilin-mediated neurodegeneration in Alzheimer's disease and other amyloidopathies. Mol Neurobiol 2007; 35:21-44. [PMID: 17519504 DOI: 10.1007/bf02700622] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Revised: 11/30/1999] [Accepted: 09/05/2006] [Indexed: 12/16/2022]
Abstract
Transport defects may arise in various neurodegenerative diseases from failures in molecular motors, microtubule abnormalities, and the chaperone/proteasomal degradation pathway leading to aggresomal-lysosomal accumulations. These defects represent important steps in the neurodegenerative cascade, although in many cases, a clear consensus has yet to be reached regarding their causal relationship to the disease. A growing body of evidence lends support to a link between neurite transport defects in the very early stages of many neurodegenerative diseases and alterations in the organization and dynamics of the actin cytoskeleton initiated by filament dynamizing proteins in the ADF/cofilin family. This article focuses on cofilin, which in neurons under stress, including stress induced by the amyloid-beta (Abeta) 1-42 peptide, undergoes dephosphorylation (activation) and forms rod-shaped actin bundles (rods). Rods inhibit transport, are sites of amyloid precursor protein accumulation, and contribute to the pathology of Alzheimer's disease. Because rods form rapidly in response to anoxia, they could also contribute to synaptic deficits associated with ischemic brain injury (e.g., stroke). Surprisingly, cofilin undergoes phosphorylation (inactivation) in hippocampal neurons treated with Abeta1-40 at high concentrations, and these neurons undergo dystrophic morphological changes, including accumulation of pretangle phosphorylated-tau. Therefore, extremes in phosphoregulation of cofilin by different forms of Abeta may explain much of the Alzheimer's disease pathology and provide mechanisms for synaptic loss and plaque expansion.
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Affiliation(s)
- Michael T Maloney
- Department of Biochemistry and Molecular Biology, Cellular and Integrative Neurosciences Program, Colorado State University, Fort Collins, CO, USA
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187
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Viña J, Lloret A, Vallés SL, Borrás C, Badía MC, Pallardó FV, Sastre J, Alonso MD. Effect of gender on mitochondrial toxicity of Alzheimer's Abeta peptide. Antioxid Redox Signal 2007; 9:1677-90. [PMID: 17822363 DOI: 10.1089/ars.2007.1773] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The aim of this article is to review the role of mitochondria in the pathogenesis of Alzheimer's disease. Additionally, the effect of gender on the incidence of Alzheimer's disease and the pathophysiological mechanisms involved will be discussed. Mitochondria, in the presence of Alzheimer's amyloid-beta peptide, increase the formation of reactive oxygen species which act both as damaging agents and also as signaling molecules. These radicals, in fact, unleash a mechanism involving the liberation of cytochrome c that leads to neuronal apoptosis. Notably, young females appear protected against the mitochondrial toxicity of amyloid-beta, likely due to the upregulation of antioxidant enzymes which occur in females. Estrogens are responsible for this effect. Overall, the findings support the notion that amyloid-beta causes intracellular toxicity via the increased production of oxidant species. Reactive oxygen species generated by mitochondria act as a signal to start the mitochondrial apoptotic pathway. There is a possibility of prevention, and indirect evidence shows that estrogenic compounds (either endogenous estradiol or phytoestrogens such as genistein) may increase the expression of antioxidant enzymes, leading to a lowering of oxidative stress and thus protection against intracellular toxicity of amyloid-beta peptide. These ideas open up the possibility of using phytoestrogens to prevent the onset of Alzheimer's disease. More studies are required to determine whether estrogens and/or phytoestrogens fulfill these expectations.
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Affiliation(s)
- Jose Viña
- Departamento de Fisiología, Facultad de Medicina, Universidad de Valencia, Valencia, Spain.
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188
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Melov S, Adlard PA, Morten K, Johnson F, Golden TR, Hinerfeld D, Schilling B, Mavros C, Masters CL, Volitakis I, Li QX, Laughton K, Hubbard A, Cherny RA, Gibson B, Bush AI. Mitochondrial oxidative stress causes hyperphosphorylation of tau. PLoS One 2007; 2:e536. [PMID: 17579710 PMCID: PMC1888726 DOI: 10.1371/journal.pone.0000536] [Citation(s) in RCA: 247] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Accepted: 05/16/2007] [Indexed: 01/20/2023] Open
Abstract
Age-related neurodegenerative disease has been mechanistically linked with mitochondrial dysfunction via damage from reactive oxygen species produced within the cell. We determined whether increased mitochondrial oxidative stress could modulate or regulate two of the key neurochemical hallmarks of Alzheimer's disease (AD): tau phosphorylation, and beta-amyloid deposition. Mice lacking superoxide dismutase 2 (SOD2) die within the first week of life, and develop a complex heterogeneous phenotype arising from mitochondrial dysfunction and oxidative stress. Treatment of these mice with catalytic antioxidants increases their lifespan and rescues the peripheral phenotypes, while uncovering central nervous system pathology. We examined sod2 null mice differentially treated with high and low doses of a catalytic antioxidant and observed striking elevations in the levels of tau phosphorylation (at Ser-396 and other phospho-epitopes of tau) in the low-dose antioxidant treated mice at AD-associated residues. This hyperphosphorylation of tau was prevented with an increased dose of the antioxidant, previously reported to be sufficient to prevent neuropathology. We then genetically combined a well-characterized mouse model of AD (Tg2576) with heterozygous sod2 knockout mice to study the interactions between mitochondrial oxidative stress and cerebral Ass load. We found that mitochondrial SOD2 deficiency exacerbates amyloid burden and significantly reduces metal levels in the brain, while increasing levels of Ser-396 phosphorylated tau. These findings mechanistically link mitochondrial oxidative stress with the pathological features of AD.
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Affiliation(s)
- Simon Melov
- Buck Institute for Age Research, Novato, California, United States of America
- * To whom correspondence should be addressed. E-mail: (SM); (AIB)
| | - Paul A. Adlard
- Mental Health Research Institute of Victoria, and Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia
| | - Karl Morten
- Buck Institute for Age Research, Novato, California, United States of America
| | - Felicity Johnson
- Buck Institute for Age Research, Novato, California, United States of America
| | - Tamara R. Golden
- Buck Institute for Age Research, Novato, California, United States of America
| | - Doug Hinerfeld
- Buck Institute for Age Research, Novato, California, United States of America
| | - Birgit Schilling
- Buck Institute for Age Research, Novato, California, United States of America
| | - Christine Mavros
- Mental Health Research Institute of Victoria, and Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia
| | - Colin L. Masters
- Mental Health Research Institute of Victoria, and Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia
| | - Irene Volitakis
- Mental Health Research Institute of Victoria, and Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia
| | - Qiao-Xin Li
- Mental Health Research Institute of Victoria, and Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia
| | - Katrina Laughton
- Mental Health Research Institute of Victoria, and Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia
| | - Alan Hubbard
- School of Public Health, EHS/Biostatistics, University of California Berkeley, Berkeley, California, United States of America
| | - Robert A. Cherny
- Mental Health Research Institute of Victoria, and Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia
| | - Brad Gibson
- Buck Institute for Age Research, Novato, California, United States of America
| | - Ashley I. Bush
- Mental Health Research Institute of Victoria, and Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
- * To whom correspondence should be addressed. E-mail: (SM); (AIB)
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189
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Cheng IH, Scearce-Levie K, Legleiter J, Palop JJ, Gerstein H, Bien-Ly N, Puoliväli J, Lesné S, Ashe KH, Muchowski PJ, Mucke L. Accelerating amyloid-beta fibrillization reduces oligomer levels and functional deficits in Alzheimer disease mouse models. J Biol Chem 2007; 282:23818-28. [PMID: 17548355 DOI: 10.1074/jbc.m701078200] [Citation(s) in RCA: 322] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many proteins suspected of causing neurodegenerative diseases exist in diverse assembly states. For most, it is unclear whether shifts from one state to another would be helpful or harmful. We used mutagenesis to change the assembly state of Alzheimer disease (AD)-associated amyloid-beta (Abeta) peptides. In vitro, the "Arctic" mutation (AbetaE22G) accelerated Abeta fibrillization but decreased the abundance of nonfibrillar Abeta assemblies, compared with wild-type Abeta. In human amyloid precursor protein (hAPP) transgenic mice carrying mutations adjacent to Abeta that increase Abeta production, addition of the Arctic mutation markedly enhanced the formation of neuritic amyloid plaques but reduced the relative abundance of a specific nonfibrillar Abeta assembly (Abeta*56). Mice overexpressing Arctic mutant or wild-type Abeta had similar behavioral and neuronal deficits when they were matched for Abeta*56 levels but had vastly different plaque loads. Thus, Abeta*56 is a likelier determinant of functional deficits in hAPP mice than fibrillar Abeta deposits. Therapeutic interventions that reduce Abeta fibrils at the cost of augmenting nonfibrillar Abeta assemblies could be harmful.
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Affiliation(s)
- Irene H Cheng
- Gladstone Institute of Neurological Disease, San Francisco, California 94158, USA
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190
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Liu W, Gnanasambandam R, Benjamin J, Kaur G, Getman PB, Siegel AJ, Shortridge RD, Singh S. Mutations in cytochrome c oxidase subunit VIa cause neurodegeneration and motor dysfunction in Drosophila. Genetics 2007; 176:937-46. [PMID: 17435251 PMCID: PMC1894620 DOI: 10.1534/genetics.107.071688] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial dysfunction is involved in many neurodegenerative disorders in humans. Here we report mutations in a gene (designated levy) that codes for subunit VIa of cytochrome c oxidase (COX). The mutations were identified by the phenotype of temperature-induced paralysis and showed the additional phenotypes of decreased COX activity, age-dependent bang-induced paralysis, progressive neurodegeneration, and reduced life span. Germ-line transformation using the levy(+) gene rescued the mutant flies from all phenotypes including neurodegeneration. The data from levy mutants reveal a COX-mediated pathway in Drosophila, disruption of which leads to mitochondrial encephalomyopathic effects including neurodegeneration, motor dysfunction, and premature death. The data present the first case of a mutation in a nuclear-encoded structural subunit of COX that causes mitochondrial encephalomyopathy rather than lethality, whereas several previous attempts to identify such mutations have not been successful. The levy mutants provide a genetic model to understand the mechanisms underlying COX-mediated mitochondrial encephalomyopathies and to explore possible therapeutic interventions.
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Affiliation(s)
- Wensheng Liu
- Department of Pharmacology and Toxicology, State University of New York, Buffalo, New York 14214 and Department of Biological Sciences, State University of New York, Buffalo, New York 14260
| | - Radhakrishnan Gnanasambandam
- Department of Pharmacology and Toxicology, State University of New York, Buffalo, New York 14214 and Department of Biological Sciences, State University of New York, Buffalo, New York 14260
| | - Jeffery Benjamin
- Department of Pharmacology and Toxicology, State University of New York, Buffalo, New York 14214 and Department of Biological Sciences, State University of New York, Buffalo, New York 14260
| | - Gunisha Kaur
- Department of Pharmacology and Toxicology, State University of New York, Buffalo, New York 14214 and Department of Biological Sciences, State University of New York, Buffalo, New York 14260
| | - Patricia B. Getman
- Department of Pharmacology and Toxicology, State University of New York, Buffalo, New York 14214 and Department of Biological Sciences, State University of New York, Buffalo, New York 14260
| | - Alan J. Siegel
- Department of Pharmacology and Toxicology, State University of New York, Buffalo, New York 14214 and Department of Biological Sciences, State University of New York, Buffalo, New York 14260
| | - Randall D. Shortridge
- Department of Pharmacology and Toxicology, State University of New York, Buffalo, New York 14214 and Department of Biological Sciences, State University of New York, Buffalo, New York 14260
| | - Satpal Singh
- Department of Pharmacology and Toxicology, State University of New York, Buffalo, New York 14214 and Department of Biological Sciences, State University of New York, Buffalo, New York 14260
- Corresponding author: Department of Pharmacology and Toxicology, 102 Farber Hall, State University of New York, Buffalo, NY 14214-3000. E-mail:
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191
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Bacsi A, Woodberry M, Kruzel ML, Boldogh I. Colostrinin delays the onset of proliferative senescence of diploid murine fibroblast cells. Neuropeptides 2007; 41:93-101. [PMID: 17300837 DOI: 10.1016/j.npep.2006.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 11/29/2006] [Accepted: 12/10/2006] [Indexed: 11/25/2022]
Abstract
Colostrinin (CLN), a uniform mixture of low-molecular weight, proline-rich polypeptides, induces neurite outgrowth of pheochromocytoma cells and inhibits beta amyloid-induced apoptosis. Moreover, its administration to patients with Alzheimer's disease resulted in improved cognitive functions. In this study, we investigated the impact of CLN on the lifespan of murine diploid fibroblast cells (MDF), an in vitro model for cellular aging. Here, we show that CLN significantly decelerates the senescence of cultured MDF and increases their population doubling levels. This action of CLN is associated with a decrease in the intracellular levels of reactive oxygen species, which may be due to senescence-associated mitochondrial dysfunction. These data suggest that CLN may delay the development of cellular aging at the level of the organism. Thus, CLN may be used in the prevention and/or therapy of diseases associated with aging processes.
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Affiliation(s)
- Attila Bacsi
- Department of Microbiology and Immunology, University of Texas Medical Branch, 3.170 Medical Research Building, 301 University Blvd, Galveston, TX 77555, USA
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192
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Wiener HW, Perry RT, Chen Z, Harrell LE, Go RCP. A polymorphism in SOD2 is associated with development of Alzheimer's disease. GENES BRAIN AND BEHAVIOR 2007; 6:770-5. [PMID: 17376152 DOI: 10.1111/j.1601-183x.2007.00308.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Genes involved in cellular mechanisms to repair oxidative damage are strong candidates as etiologic factors for Alzheimer's disease (AD). One important enzyme involved in this mechanism is superoxide dismutase 2 (SOD2). The gene for this enzyme lies within a single haplotype block at 6q25.3, a region showing evidence for linkage to AD in a genome scan. We genotyped four single nucleotide polymorphisms (SNPs) in SOD2 in families of the National Institute of Mental Health-AD Genetics Initiative (ADGI): rs2758346 in the 5' untranslated region (UTR), rs4880 in exon 2, rs2855116 in intron 3 and rs5746136 in the 3'UTR. Under a dominant model, family-based association tests showed significant evidence for association of AD with the first three loci in a candidate gene set of families with individuals having age of onset of at least 50 years and two affected and one unaffected sibling, and in a late-onset subset of families (families with all affected individuals having age of onset of at least 65 years) from the full ADGI sample. The alleles transmitted more frequently to cases than expected under the null hypothesis were T, C, G, and G. Global tests of the transmission of haplotypes indicate that the first two loci have the most consistent association with risk of AD. Because of the high linkage disequilibrium in this small (14 kb) gene, and the presence of 100 SNPs in this gene, 26 of which may have functional significance, additional genotyping and sequencing are needed to identify the functionally relevant SNP. We discuss the importance of our findings and the relevance of SOD2 to AD risk.
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Affiliation(s)
- H W Wiener
- Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, AL 35294-0022, USA.
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193
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Abstract
Superoxide dismutases (SODs) are the major antioxidant enzymes that inactivate superoxide and thereby control oxidative stress as well as redox signaling. Transgenic mice overexpressing different isozymes of SOD have been used to study the effect of SOD overexpression on hippocampal synaptic plasticity and hippocampus-dependent learning and memory. Studies with transgenic and wild-type animals of different ages show that the function of SOD overexpression changes across the life span of an animal, and comparisons between animals that overexpress different SOD isozymes suggest that the functional value of overexpression as well as the mechanisms through which the respective functional values are effected vary depending on isozyme. The work discussed in this review has important implications for the use of antioxidant treatments and for our understanding of the role of superoxide in physiological and pathological processes.
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Affiliation(s)
- Daoying Hu
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, Texas, USA
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194
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Hu D, Cao P, Thiels E, Chu CT, Wu GY, Oury TD, Klann E. Hippocampal long-term potentiation, memory, and longevity in mice that overexpress mitochondrial superoxide dismutase. Neurobiol Learn Mem 2006; 87:372-84. [PMID: 17129739 PMCID: PMC1847321 DOI: 10.1016/j.nlm.2006.10.003] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2006] [Revised: 10/04/2006] [Accepted: 10/16/2006] [Indexed: 12/14/2022]
Abstract
Superoxide has been shown to be critically involved in several pathological manifestations of aging animals. In contrast, superoxide also can act as a signaling molecule to modulate signal transduction cascades required for hippocampal synaptic plasticity. Mitochondrial superoxide dismutase (SOD-2 or Mn-SOD) is a key antioxidant enzyme that scavenges superoxide. Thus, SOD-2 may not only prevent aging-related oxidative stress, but may also regulate redox signaling in young animals. We used transgenic mice overexpressing SOD-2 to study the role of mitochondrial superoxide in aging, synaptic plasticity, and memory-associated behavior. We found that overexpression of SOD-2 had no obvious effect on synaptic plasticity and memory formation in young mice, and could not rescue the age-related impairments in either synaptic plasticity or memory in old mice. However, SOD-2 overexpression did decrease mitochondrial superoxide in hippocampal neurons, and extended the lifespan of the mice. These findings increase our knowledge of the role of mitochondrial superoxide in physiological and pathological processes in the brain.
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Affiliation(s)
- Daoying Hu
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030
| | - Peng Cao
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030
| | - Edda Thiels
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
- Center for the Neural Basis of Cognition, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Charleen T. Chu
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Gang-yi Wu
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030
| | - Tim D. Oury
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Eric Klann
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030
- * Correspondence should be sent to: Eric Klann, Ph.D., Department of Molecular Physiology & Biophysics, Baylor College of Medicine, One Baylor Plaza BCM 335, Houston, TX 77030, Phone: (713) 798-5630, Fax: (713) 798-3475, E-mail:
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195
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Zhu X, Lee HG, Perry G, Smith MA. Alzheimer disease, the two-hit hypothesis: an update. Biochim Biophys Acta Mol Basis Dis 2006; 1772:494-502. [PMID: 17142016 DOI: 10.1016/j.bbadis.2006.10.014] [Citation(s) in RCA: 201] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Revised: 10/23/2006] [Accepted: 10/24/2006] [Indexed: 11/21/2022]
Abstract
Given the relative modality of single-insult models to accurately reflect Alzheimer disease pathogenesis, based on studies on mitogenic and oxidative stress signaling pathways, we proposed a two-hit hypothesis 2 years ago stating that both oxidative stress and mitogenic dysregulation are necessary and sufficient to cause the disease and suggested that it may be a common mechanism for other neurodegenerative diseases as well (X. Zhu, A.K. Raina, G. Perry, M.A. Smith, Alzheimer's disease: the two-hit hypothesis, Lancet Neurol. 3 (2004) 219-226). Recent developments in the field confirm some important predictions of the hypothesis and shed new lights on potential mechanisms regarding how steady state may be achieved in sporadic AD cases and therefore, in our opinion, strengthen the hypothesis, which will be the focus of this review.
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Affiliation(s)
- Xiongwei Zhu
- Department of Pathology, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA.
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196
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Hague T, Andrews PLR, Barker J, Naughton DP. Dietary chelators as antioxidant enzyme mimetics: implications for dietary intervention in neurodegenerative diseases. Behav Pharmacol 2006; 17:425-30. [PMID: 16940763 DOI: 10.1097/00008877-200609000-00008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Following recent reviews on the role of metal ions in oxidative stress and neurodegenerative diseases, this article reports advances in the study of dietary components for the control of these conditions. Poor metal ion homeostasis is credited with pathological roles in the progression of a number of disorders including Alzheimer's disease, Parkinson's disease and multiple sclerosis. Synthetic metal ion chelators continue to show promise as a new therapeutic approach for neurodegenerative disorders. Dietary chelators, unlike most vitamins, are, however, capable of negating or even reversing the roles of metal ions by: (i) decorporation of metal ions, (ii) redox silencing, (iii) dissolution of deposits, and (iv) generation of an antioxidant enzyme mimetic. This review gives a critical evaluation of recent progress in, and potential for, dietary control of neurodegeneration on the basis of the formation of antioxidant enzyme mimetics.
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Affiliation(s)
- Theresa Hague
- School of Life Sciences, Kingston University, Kingston-upon-Thames, Surrey, UK
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