51
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García-Beltrán O, Mena NP, Aguirre P, Barriga-González G, Galdámez A, Nagles E, Adasme T, Hidalgo C, Núñez MT. Development of an iron-selective antioxidant probe with protective effects on neuronal function. PLoS One 2017; 12:e0189043. [PMID: 29228015 PMCID: PMC5724820 DOI: 10.1371/journal.pone.0189043] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 11/19/2017] [Indexed: 12/19/2022] Open
Abstract
Iron accumulation, oxidative stress and calcium signaling dysregulation are common pathognomonic signs of several neurodegenerative diseases, including Parkinson´s and Alzheimer’s diseases, Friedreich ataxia and Huntington’s disease. Given their therapeutic potential, the identification of multifunctional compounds that suppress these damaging features is highly desirable. Here, we report the synthesis and characterization of N-(1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl)-2-(7-hydroxy-2-oxo-2H-chromen-4-yl)acetamide, named CT51, which exhibited potent free radical neutralizing activity both in vitro and in cells. CT51 bound Fe2+ with high selectivity and Fe3+ with somewhat lower affinity. Cyclic voltammetric analysis revealed irreversible binding of Fe3+ to CT51, an important finding since stopping Fe2+/Fe3+ cycling in cells should prevent hydroxyl radical production resulting from the Fenton-Haber-Weiss cycle. When added to human neuroblastoma cells, CT51 freely permeated the cell membrane and distributed to both mitochondria and cytoplasm. Intracellularly, CT51 bound iron reversibly and protected against lipid peroxidation. Treatment of primary hippocampal neurons with CT51 reduced the sustained calcium release induced by an agonist of ryanodine receptor-calcium channels. These protective properties of CT51 on cellular function highlight its possible therapeutic use in diseases with significant oxidative, iron and calcium dysregulation.
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Affiliation(s)
- Olimpo García-Beltrán
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Natalia P. Mena
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Pabla Aguirre
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Germán Barriga-González
- Universidad Metropolitana de Ciencias de la Educación, Facultad de Ciencias Básicas, Departamento de Química, Santiago, Chile
| | - Antonio Galdámez
- Department of Chemistry, Faculty of Sciences, University of Chile, Santiago, Chile
| | - Edgar Nagles
- Facultad de Ciencias Naturales y Matemáticas, Universidad de Ibagué, Ibagué, Colombia
| | - Tatiana Adasme
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Integrative Center for Applied Biology and Chemistry (CIBQA), Universidad Bernardo O’Higgins, Santiago, Chile
| | - Cecilia Hidalgo
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Department of Neuroscience, CEMC and ICBM, Faculty of Medicine, Universidad de Chile, Santiago, Chile
- * E-mail: (CH); (MTN)
| | - Marco T. Núñez
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
- * E-mail: (CH); (MTN)
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52
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Lacampagne A, Liu X, Reiken S, Bussiere R, Meli AC, Lauritzen I, Teich AF, Zalk R, Saint N, Arancio O, Bauer C, Duprat F, Briggs CA, Chakroborty S, Stutzmann GE, Shelanski ML, Checler F, Chami M, Marks AR. Post-translational remodeling of ryanodine receptor induces calcium leak leading to Alzheimer's disease-like pathologies and cognitive deficits. Acta Neuropathol 2017. [PMID: 28631094 DOI: 10.1007/s00401-017-1733-7] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The mechanisms underlying ryanodine receptor (RyR) dysfunction associated with Alzheimer disease (AD) are still not well understood. Here, we show that neuronal RyR2 channels undergo post-translational remodeling (PKA phosphorylation, oxidation, and nitrosylation) in brains of AD patients, and in two murine models of AD (3 × Tg-AD, APP +/- /PS1 +/-). RyR2 is depleted of calstabin2 (KFBP12.6) in the channel complex, resulting in endoplasmic reticular (ER) calcium (Ca2+) leak. RyR-mediated ER Ca2+ leak activates Ca2+-dependent signaling pathways, contributing to AD pathogenesis. Pharmacological (using a novel RyR stabilizing drug Rycal) or genetic rescue of the RyR2-mediated intracellular Ca2+ leak improved synaptic plasticity, normalized behavioral and cognitive functions and reduced Aβ load. Genetically altered mice with congenitally leaky RyR2 exhibited premature and severe defects in synaptic plasticity, behavior and cognitive function. These data provide a mechanism underlying leaky RyR2 channels, which could be considered as potential AD therapeutic targets.
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53
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Park J, Kim B, Chae U, Lee DG, Kam MK, Lee SR, Lee S, Lee HS, Park JW, Lee DS. Peroxiredoxin 5 Decreases Beta-Amyloid-Mediated Cyclin-Dependent Kinase 5 Activation Through Regulation of Ca 2+-Mediated Calpain Activation. Antioxid Redox Signal 2017; 27:715-726. [PMID: 28358580 DOI: 10.1089/ars.2016.6810] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
AIMS Aberrant Cdk5 (cyclin-dependent kinase 5) and oxidative stress are crucial components of diverse neurodegenerative disorders, including Alzheimer's disease (AD). We previously reported that a change in peroxiredoxin (Prx) expression is associated with protection from neuronal death. The aim of the current study was to analyze the role of Prx in regulating Cdk5 activation in AD. RESULTS We found that of the six Prx subtypes, Prx5 was increased the most in cellular (N2a-APPswe cells) model of AD. Prx5 in the brain of APP (amyloid precursor protein) transgenic mouse (Tg2576) was more increased than a nontransgenic mouse. We evaluated Prx5 function by using overexpression (Prx5-WT), a mutation in the catalytic residue (Prx5-C48S), and knockdown. Increased neuronal death and Cdk5 activation by amyloid beta oligomer (AβO) were rescued by Prx5-WT expression, but not by Prx5-C48S or Prx5 knockdown. Prx5 plays a role in Cdk5 regulation by inhibiting the conversion of p35 to p25, which is increased by AβO accumulation. Prx5 is also upregulated in both the cytosol and mitochondria and it protects cells from AβO-mediated oxidative stress by eliminating intracellular and mitochondrial reactive oxygen species. Moreover, Prx5 regulates Ca2+ and Ca2+-mediated calpain activation, which are key regulators of p35 cleavage to p25. Innovation and Conclusion: Our study represents the first demonstration that Prx5 induction is a key factor in the suppression of Cdk5-related neuronal death in AD and we show that it functions via regulation of Ca2+-mediated calpain activation. Antioxid. Redox Signal. 27, 715-726.
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Affiliation(s)
- Junghyung Park
- 1 School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University , Daegu, Republic of Korea.,2 College of Natural Sciences, Kyungpook National University , Daegu, Republic of Korea
| | - Bokyung Kim
- 1 School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University , Daegu, Republic of Korea.,2 College of Natural Sciences, Kyungpook National University , Daegu, Republic of Korea
| | - Unbin Chae
- 1 School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University , Daegu, Republic of Korea.,2 College of Natural Sciences, Kyungpook National University , Daegu, Republic of Korea
| | - Dong Gil Lee
- 1 School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University , Daegu, Republic of Korea.,2 College of Natural Sciences, Kyungpook National University , Daegu, Republic of Korea
| | - Min Kyoung Kam
- 1 School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University , Daegu, Republic of Korea.,2 College of Natural Sciences, Kyungpook National University , Daegu, Republic of Korea
| | - Sang-Rae Lee
- 3 National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB) , Cheongju, Republic of Korea
| | - Seunghoon Lee
- 4 Animal Biotechnology Division, National Institute of Animal Science , Jeonju, Republic of Korea
| | - Hyun-Shik Lee
- 1 School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University , Daegu, Republic of Korea.,2 College of Natural Sciences, Kyungpook National University , Daegu, Republic of Korea
| | - Jeen-Woo Park
- 1 School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University , Daegu, Republic of Korea.,2 College of Natural Sciences, Kyungpook National University , Daegu, Republic of Korea
| | - Dong-Seok Lee
- 1 School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University , Daegu, Republic of Korea.,2 College of Natural Sciences, Kyungpook National University , Daegu, Republic of Korea
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54
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Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative disorder and the most common cause of dementia among aged people whose population is rapidly increasing. AD not only seriously affects the patient's physical health and quality of life, but also adds a heavy burden to the patient's family and society. It is urgent to understand AD pathogenesis and develop the means of prevention and treatment. AD is a chronic devastating neurodegenerative disease without effective treatment. Current approaches for management focus on helping patients relieve or delay the symptoms of cognitive dysfunction. The calcium ion (Ca2+) is an important second messenger in the function and structure of nerve cell circuits in the brain such as neuronal growth, exocytosis, as well as in synaptic and cognitive function. Increasing numbers of studies suggested that disruption of intracellular Ca2+ homeostasis, especially the abnormal and excessive Ca2+ release from the endoplasmic reticulum (ER) via the ryanodine receptor (RYR), plays important roles in orchestrating the dynamic of the neuropathology of AD and associated memory loss, cognitive dysfunction. Dantrolene, a known antagonist of the RYR and a clinically available drug to treat malignant hyperthermia, can ameliorate the abnormal Ca2+ release from the RYR in AD and the subsequent pathogenesis, such as increased β-secretase and γ-secretase activities, production of Amyloid-β 42 (Aβ 42) and its oligomer, impaired autophagy, synapse dysfunction, and memory loss. However, more studies are needed to confirm the efficacy and safety repurposing dantrolene as a therapeutic drug in AD.
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Affiliation(s)
- Yong Wang
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Department of Anesthesiology, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou 510405, China
| | - Yun Shi
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Department of Anesthesiology, Children's Hospital of Fudan University, Shanghai, 201102, China
| | - Huafeng Wei
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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55
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Bhounsule AS, Bhatt LK, Prabhavalkar KS, Oza M. Cyclin dependent kinase 5: A novel avenue for Alzheimer’s disease. Brain Res Bull 2017; 132:28-38. [DOI: 10.1016/j.brainresbull.2017.05.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/10/2017] [Indexed: 10/19/2022]
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56
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Sprenkle NT, Sims SG, Sánchez CL, Meares GP. Endoplasmic reticulum stress and inflammation in the central nervous system. Mol Neurodegener 2017; 12:42. [PMID: 28545479 PMCID: PMC5445486 DOI: 10.1186/s13024-017-0183-y] [Citation(s) in RCA: 182] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 05/17/2017] [Indexed: 12/14/2022] Open
Abstract
Persistent endoplasmic reticulum (ER) stress is thought to drive the pathology of many chronic disorders due to its potential to elicit aberrant inflammatory signaling and facilitate cell death. In neurodegenerative diseases, the accumulation of misfolded proteins and concomitant induction of ER stress in neurons contributes to neuronal dysfunction. In addition, ER stress responses induced in the surrounding neuroglia may promote disease progression by coordinating damaging inflammatory responses, which help fuel a neurotoxic milieu. Nevertheless, there still remains a gap in knowledge regarding the cell-specific mechanisms by which ER stress mediates neuroinflammation. In this review, we will discuss recently uncovered inflammatory pathways linked to the ER stress response. Moreover, we will summarize the present literature delineating how ER stress is generated in Alzheimer’s disease, Parkinson’s disease, Amyotrophic Lateral Sclerosis, and Multiple Sclerosis, and highlight how ER stress and neuroinflammation intersect mechanistically within the central nervous system. The mechanisms by which stress-induced inflammation contributes to the pathogenesis and progression of neurodegenerative diseases remain poorly understood. Further examination of this interplay could present unappreciated insights into the development of neurodegenerative diseases, and reveal new therapeutic targets.
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Affiliation(s)
- Neil T Sprenkle
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, One Medical Center Drive, BMRC, Morgantown, WV, 311, USA
| | - Savannah G Sims
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, One Medical Center Drive, BMRC, Morgantown, WV, 311, USA
| | - Cristina L Sánchez
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, One Medical Center Drive, BMRC, Morgantown, WV, 311, USA
| | - Gordon P Meares
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, One Medical Center Drive, BMRC, Morgantown, WV, 311, USA. .,Blanchette Rockefeller Neurosciences Institute, West Virginia University School of Medicine, Morgantown, WV, USA.
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57
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Bussiere R, Lacampagne A, Reiken S, Liu X, Scheuerman V, Zalk R, Martin C, Checler F, Marks AR, Chami M. Amyloid β production is regulated by β2-adrenergic signaling-mediated post-translational modifications of the ryanodine receptor. J Biol Chem 2017; 292:10153-10168. [PMID: 28476886 PMCID: PMC5473221 DOI: 10.1074/jbc.m116.743070] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 05/02/2017] [Indexed: 11/06/2022] Open
Abstract
Alteration of ryanodine receptor (RyR)-mediated calcium (Ca2+) signaling has been reported in Alzheimer disease (AD) models. However, the molecular mechanisms underlying altered RyR-mediated intracellular Ca2+ release in AD remain to be fully elucidated. We report here that RyR2 undergoes post-translational modifications (phosphorylation, oxidation, and nitrosylation) in SH-SY5Y neuroblastoma cells expressing the β-amyloid precursor protein (βAPP) harboring the familial double Swedish mutations (APPswe). RyR2 macromolecular complex remodeling, characterized by depletion of the regulatory protein calstabin2, resulted in increased cytosolic Ca2+ levels and mitochondrial oxidative stress. We also report a functional interplay between amyloid β (Aβ), β-adrenergic signaling, and altered Ca2+ signaling via leaky RyR2 channels. Thus, post-translational modifications of RyR occur downstream of Aβ through a β2-adrenergic signaling cascade that activates PKA. RyR2 remodeling in turn enhances βAPP processing. Importantly, pharmacological stabilization of the binding of calstabin2 to RyR2 channels, which prevents Ca2+ leakage, or blocking the β2-adrenergic signaling cascade reduced βAPP processing and the production of Aβ in APPswe-expressing SH-SY5Y cells. We conclude that targeting RyR-mediated Ca2+ leakage may be a therapeutic approach to treat AD.
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Affiliation(s)
- Renaud Bussiere
- From the Université Côte d'Azur, CNRS, IPMC, France, "Labex Distalz," 660 route des Lucioles, 06560 Sophia-Antipolis, Valbonne, France
| | - Alain Lacampagne
- INSERM U1046, CNRS UMR9214, CNRS LIA1185, Université de Montpellier, CHRU Montpellier, 34295 Montpellier, France, and
| | - Steven Reiken
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Xiaoping Liu
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Valerie Scheuerman
- INSERM U1046, CNRS UMR9214, CNRS LIA1185, Université de Montpellier, CHRU Montpellier, 34295 Montpellier, France, and
| | - Ran Zalk
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Cécile Martin
- From the Université Côte d'Azur, CNRS, IPMC, France, "Labex Distalz," 660 route des Lucioles, 06560 Sophia-Antipolis, Valbonne, France
| | - Frederic Checler
- From the Université Côte d'Azur, CNRS, IPMC, France, "Labex Distalz," 660 route des Lucioles, 06560 Sophia-Antipolis, Valbonne, France
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Mounia Chami
- From the Université Côte d'Azur, CNRS, IPMC, France, "Labex Distalz," 660 route des Lucioles, 06560 Sophia-Antipolis, Valbonne, France,
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58
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SanMartín CD, Veloso P, Adasme T, Lobos P, Bruna B, Galaz J, García A, Hartel S, Hidalgo C, Paula-Lima AC. RyR2-Mediated Ca 2+ Release and Mitochondrial ROS Generation Partake in the Synaptic Dysfunction Caused by Amyloid β Peptide Oligomers. Front Mol Neurosci 2017; 10:115. [PMID: 28487634 PMCID: PMC5403897 DOI: 10.3389/fnmol.2017.00115] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 04/05/2017] [Indexed: 11/13/2022] Open
Abstract
Amyloid β peptide oligomers (AβOs), toxic aggregates with pivotal roles in Alzheimer's disease, trigger persistent and low magnitude Ca2+ signals in neurons. We reported previously that these Ca2+ signals, which arise from Ca2+ entry and subsequent amplification by Ca2+ release through ryanodine receptor (RyR) channels, promote mitochondrial network fragmentation and reduce RyR2 expression. Here, we examined if AβOs, by inducing redox sensitive RyR-mediated Ca2+ release, stimulate mitochondrial Ca2+-uptake, ROS generation and mitochondrial fragmentation, and also investigated the effects of the antioxidant N-acetyl cysteine (NAC) and the mitochondrial antioxidant EUK-134 on AβOs-induced mitochondrial dysfunction. In addition, we studied the contribution of the RyR2 isoform to AβOs-induced Ca2+ release, mitochondrial Ca2+ uptake and fragmentation. We show here that inhibition of NADPH oxidase type-2 prevented the emergence of RyR-mediated cytoplasmic Ca2+ signals induced by AβOs in primary hippocampal neurons. Treatment with AβOs promoted mitochondrial Ca2+ uptake and increased mitochondrial superoxide and hydrogen peroxide levels; ryanodine, at concentrations that suppress RyR activity, prevented these responses. The antioxidants NAC and EUK-134 impeded the mitochondrial ROS increase induced by AβOs. Additionally, EUK-134 prevented the mitochondrial fragmentation induced by AβOs, as previously reported for NAC and ryanodine. These findings show that both antioxidants, NAC and EUK-134, prevented the Ca2+-mediated noxious effects of AβOs on mitochondrial function. Our results also indicate that Ca2+ release mediated by the RyR2 isoform causes the deleterious effects of AβOs on mitochondrial function. Knockdown of RyR2 with antisense oligonucleotides reduced by about 50% RyR2 mRNA and protein levels in primary hippocampal neurons, decreased by 40% Ca2+ release induced by the RyR agonist 4-chloro-m-cresol, and significantly reduced the cytoplasmic and mitochondrial Ca2+ signals and the mitochondrial fragmentation induced by AβOs. Based on our results, we propose that AβOs-induced Ca2+ entry and ROS generation jointly stimulate RyR2 activity, causing mitochondrial Ca2+ overload and fragmentation in a feed forward injurious cycle. The present novel findings highlight the specific participation of RyR2-mediated Ca2+ release on AβOs-induced mitochondrial malfunction.
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Affiliation(s)
- Carol D SanMartín
- Department of de Neurology and Neurosurgery, Clinical Hospital Universidad de ChileSantiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de ChileSantiago, Chile
| | - Pablo Veloso
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de ChileSantiago, Chile.,Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de ChileSantiago, Chile
| | - Tatiana Adasme
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de ChileSantiago, Chile.,Centro Integrativo de Biología y Química Aplicada, Universidad Bernardo O HigginsSantiago, Chile
| | - Pedro Lobos
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de ChileSantiago, Chile
| | - Barbara Bruna
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de ChileSantiago, Chile
| | - Jose Galaz
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de ChileSantiago, Chile
| | - Alejandra García
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de ChileSantiago, Chile.,Anatomy and Developmental Biology Program, Institute of Biomedical Sciences, Center of Medical Informatics and Telemedicine and National Center for Health Information Systems, Faculty of Medicine, Universidad de ChileSantiago, Chile
| | - Steffen Hartel
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de ChileSantiago, Chile.,Anatomy and Developmental Biology Program, Institute of Biomedical Sciences, Center of Medical Informatics and Telemedicine and National Center for Health Information Systems, Faculty of Medicine, Universidad de ChileSantiago, Chile
| | - Cecilia Hidalgo
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de ChileSantiago, Chile.,Physiology and Biophysics Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de ChileSantiago, Chile
| | - Andrea C Paula-Lima
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de ChileSantiago, Chile.,Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de ChileSantiago, Chile
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59
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Seixas da Silva GS, Melo HM, Lourenco MV, Lyra E Silva NM, de Carvalho MB, Alves-Leon SV, de Souza JM, Klein WL, da-Silva WS, Ferreira ST, De Felice FG. Amyloid-β oligomers transiently inhibit AMP-activated kinase and cause metabolic defects in hippocampal neurons. J Biol Chem 2017; 292:7395-7406. [PMID: 28302722 DOI: 10.1074/jbc.m116.753525] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 03/15/2017] [Indexed: 11/06/2022] Open
Abstract
AMP-activated kinase (AMPK) is a key player in energy sensing and metabolic reprogramming under cellular energy restriction. Several studies have linked impaired AMPK function to peripheral metabolic diseases such as diabetes. However, the impact of neurological disorders, such as Alzheimer disease (AD), on AMPK function and downstream effects of altered AMPK activity on neuronal metabolism have been investigated only recently. Here, we report the impact of Aβ oligomers (AβOs), synaptotoxins that accumulate in AD brains, on neuronal AMPK activity. Short-term exposure of cultured rat hippocampal neurons or ex vivo human cortical slices to AβOs transiently decreased intracellular ATP levels and AMPK activity, as evaluated by its phosphorylation at threonine residue 172 (AMPK-Thr(P)172). The AβO-dependent reduction in AMPK-Thr(P)172 levels was mediated by glutamate receptors of the N-methyl-d-aspartate (NMDA) subtype and resulted in removal of glucose transporters (GLUTs) from the surfaces of dendritic processes in hippocampal neurons. Importantly, insulin prevented the AβO-induced inhibition of AMPK. Our results establish a novel toxic impact of AβOs on neuronal metabolism and suggest that AβO-induced, NMDA receptor-mediated AMPK inhibition may play a key role in early brain metabolic defects in AD.
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Affiliation(s)
| | - Helen M Melo
- From the Institute of Medical Biochemistry Leopoldo de Meis and
| | - Mychael V Lourenco
- From the Institute of Medical Biochemistry Leopoldo de Meis and.,the Institute of Biophysics Carlos Chagas Filho
| | | | | | | | - Jorge M de Souza
- Neurosurgery, Clementino Fraga Filho Hospital, Federal University of Rio De Janeiro, Rio de Janeiro 21941-902, Brazil
| | - William L Klein
- the Department of Neurobiology, Northwestern University, Evanston, Illinois 60208-3520, and
| | | | - Sergio T Ferreira
- From the Institute of Medical Biochemistry Leopoldo de Meis and.,the Institute of Biophysics Carlos Chagas Filho
| | - Fernanda G De Felice
- From the Institute of Medical Biochemistry Leopoldo de Meis and .,the Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
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60
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Zhang Y, Song W. Islet amyloid polypeptide: Another key molecule in Alzheimer's pathogenesis? Prog Neurobiol 2017; 153:100-120. [PMID: 28274676 DOI: 10.1016/j.pneurobio.2017.03.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 02/17/2017] [Accepted: 03/02/2017] [Indexed: 12/14/2022]
Abstract
Recent epidemiological evidence reveals that patients suffering from type 2 diabetes mellitus (T2DM) often experience a significant decline in cognitive function, and approximately 70% of those cases eventually develop Alzheimer's disease (AD). Although several pathological processes are shared by AD and T2DM, the exact molecular mechanisms connecting these two diseases are poorly understood. Aggregation of human islet amyloid polypeptide (hIAPP), the pathological hallmark of T2DM, has also been detected in brain tissue and is associated with cognitive decline and AD development. In addition, hIAPP and amyloid β protein (Aβ) share many biophysical and physiological properties as well as exert similar cytotoxic mechanisms. Therefore, it is important to examine the possible role of hIAPP in the pathogenesis of AD. In this article, we introduce the basics on this amyloidogenic protein. More importantly, we discuss the potential mechanisms of hIAPP-induced AD development, which will be beneficial for proposing novel and feasible strategies to optimize AD prevention and/or treatment in diabetics.
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Affiliation(s)
- Yun Zhang
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| | - Weihong Song
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada.
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61
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Zolezzi JM, Santos MJ, Bastías-Candia S, Pinto C, Godoy JA, Inestrosa NC. PPARs in the central nervous system: roles in neurodegeneration and neuroinflammation. Biol Rev Camb Philos Soc 2017; 92:2046-2069. [PMID: 28220655 DOI: 10.1111/brv.12320] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 12/21/2016] [Accepted: 01/11/2017] [Indexed: 12/20/2022]
Abstract
Over 25 years have passed since peroxisome proliferators-activated receptors (PPARs), were first described. Like other members of the nuclear receptors superfamily, PPARs have been defined as critical sensors and master regulators of cellular metabolism. Recognized as ligand-activated transcription factors, they are involved in lipid, glucose and amino acid metabolism, taking part in different cellular processes, including cellular differentiation and apoptosis, inflammatory modulation and attenuation of acute and chronic neurological damage in vivo and in vitro. Interestingly, PPAR activation can simultaneously reprogram the immune response, stimulate metabolic and mitochondrial functions, promote axonal growth, induce progenitor cells to differentiate into myelinating oligodendrocytes, and improve brain clearance of toxic molecules such as β-amyloid peptide. Although the molecular mechanisms and cross-talk with different molecular pathways are still the focus of intense research, PPARs are considered potential therapeutic targets for several neuropathological conditions, including degenerative disorders such as Alzheimer's, Parkinson's and Huntington's disease. This review considers recent advances regarding PPARs, as well as new PPAR agonists. We focus on the mechanisms behind the neuroprotective effects exerted by PPARs and summarise the roles of PPARs in different pathologies of the central nervous system, especially those associated with degenerative and inflammatory mechanisms.
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Affiliation(s)
- Juan M Zolezzi
- Centro de Envejecimiento y Regeneración (CARE-UC), P. Catholic University of Chile, PO Box 114-D, 8331150, Santiago, Chile
| | - Manuel J Santos
- Facultad de Ciencias Biológicas, Departamento de Biología Celular y Molecular, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile
| | - Sussy Bastías-Candia
- Facultad de Ciencias, Departamento de Biología, Universidad de Tarapacá, Gral. Velásquez 1775, 1000007, Arica, Chile
| | - Claudio Pinto
- Centro de Envejecimiento y Regeneración (CARE-UC), P. Catholic University of Chile, PO Box 114-D, 8331150, Santiago, Chile
| | - Juan A Godoy
- Centro de Envejecimiento y Regeneración (CARE-UC), P. Catholic University of Chile, PO Box 114-D, 8331150, Santiago, Chile.,Facultad de Ciencias Biológicas, Departamento de Biología Celular y Molecular, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile
| | - Nibaldo C Inestrosa
- Centro de Envejecimiento y Regeneración (CARE-UC), P. Catholic University of Chile, PO Box 114-D, 8331150, Santiago, Chile.,Facultad de Ciencias Biológicas, Departamento de Biología Celular y Molecular, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile.,Faculty of Medicine, Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales, Avoca Street Randwick NSW 2031, Sydney, Australia.,Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, PO Box 113-D, Avenida Bulnes 01855, 6210427, Punta Arenas, Chile
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Foster TC, Kyritsopoulos C, Kumar A. Central role for NMDA receptors in redox mediated impairment of synaptic function during aging and Alzheimer's disease. Behav Brain Res 2016; 322:223-232. [PMID: 27180169 DOI: 10.1016/j.bbr.2016.05.012] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 04/15/2016] [Accepted: 05/05/2016] [Indexed: 01/07/2023]
Abstract
Increased human longevity has magnified the negative impact that aging can have on cognitive integrity of older individuals experiencing some decline in cognitive function. Approximately 30% of the elderly will have cognitive problems that influence their independence. Impaired executive function and memory performance are observed in normal aging and yet can be an early sign of a progressive cognitive impairment of Alzheimer's disease (AD), the most common form of dementia. Brain regions that are vulnerable to aging exhibit the earliest pathology of AD. Senescent synaptic function is observed as a shift in Ca2+-dependent synaptic plasticity and similar mechanisms are thought to contribute to the early cognitive deficits associated with AD. In the case of aging, intracellular redox state mediates a shift in Ca2+ regulation including N-methyl-d-aspartate (NMDA) receptor hypofunction and increased Ca2+ release from intracellular stores to alter synaptic plasticity. AD can interact with these aging processes such that molecules linked to AD, β-amyloid (Aβ) and mutated presenilin 1 (PS1), can also degrade NMDA receptor function, promote Ca2+ release from intracellular stores, and may increase oxidative stress. Thus, age is one of the most important predictors of AD and brain aging likely contributes to the onset of AD. The focus of this review article is to provide an update on mechanisms that contribute to the senescent synapse and possible interactions with AD-related molecules, with special emphasis on regulation of NMDA receptors.
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Affiliation(s)
- T C Foster
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, United States of America.
| | - C Kyritsopoulos
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, United States of America
| | - A Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, United States of America.
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Astaxanthin Protects Primary Hippocampal Neurons against Noxious Effects of Aβ-Oligomers. Neural Plast 2016; 2016:3456783. [PMID: 27034843 PMCID: PMC4791503 DOI: 10.1155/2016/3456783] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Revised: 12/28/2015] [Accepted: 02/01/2016] [Indexed: 12/31/2022] Open
Abstract
Increased reactive oxygen species (ROS) generation and the ensuing oxidative stress contribute to Alzheimer's disease pathology. We reported previously that amyloid-β peptide oligomers (AβOs) produce aberrant Ca2+ signals at sublethal concentrations and decrease the expression of type-2 ryanodine receptors (RyR2), which are crucial for hippocampal synaptic plasticity and memory. Here, we investigated whether the antioxidant agent astaxanthin (ATX) protects neurons from AβOs-induced excessive mitochondrial ROS generation, NFATc4 activation, and RyR2 mRNA downregulation. To determine mitochondrial H2O2 production or NFATc4 nuclear translocation, neurons were transfected with plasmids coding for HyperMito or NFATc4-eGFP, respectively. Primary hippocampal cultures were incubated with 0.1 μM ATX for 1.5 h prior to AβOs addition (500 nM). We found that incubation with ATX (≤10 μM) for ≤24 h was nontoxic to neurons, evaluated by the live/dead assay. Preincubation with 0.1 μM ATX also prevented the neuronal mitochondrial H2O2 generation induced within minutes of AβOs addition. Longer exposures to AβOs (6 h) promoted NFATc4-eGFP nuclear translocation and decreased RyR2 mRNA levels, evaluated by detection of the eGFP-tagged fluorescent plasmid and qPCR, respectively. Preincubation with 0.1 μM ATX prevented both effects. These results indicate that ATX protects neurons from the noxious effects of AβOs on mitochondrial ROS production, NFATc4 activation, and RyR2 gene expression downregulation.
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64
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Segal M, Korkotian E. Roles of Calcium Stores and Store-Operated Channels in Plasticity of Dendritic Spines. Neuroscientist 2015; 22:477-85. [PMID: 26511041 DOI: 10.1177/1073858415613277] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Calcium stores in the endoplasmic reticulum play important roles in a variety of mammalian cellular functions. However, the multitude of calcium-handling machineries in neurons, including voltage- and ligand-gated channels, calcium-binding proteins, pumps, and transporters, as well as the rapid mobility of calcium ions among different cellular compartments hampered the singling out of calcium stores as a pivotal player in synaptic plasticity. Despite these methodological obstacles, novel molecular and imaging tools afforded a rapid progress in deciphering the role of specific calcium stores in neuronal functions. In the present review, we will address several key issues related to the involvement of ryanodine receptors and the calcium entry channel Orai1 in dendritic spine development and plasticity as well as their derailing in neurodegenerative diseases.
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Affiliation(s)
- Menahem Segal
- Department of Neurobiology, The Weizmann Institute, Rehovot, Israel
| | - Eduard Korkotian
- Department of Neurobiology, The Weizmann Institute, Rehovot, Israel
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65
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Mahdi AA, Rizvi SHM, Parveen A. Role of Endoplasmic Reticulum Stress and Unfolded Protein Responses in Health and Diseases. Indian J Clin Biochem 2015; 31:127-37. [PMID: 27069320 DOI: 10.1007/s12291-015-0502-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 04/12/2015] [Indexed: 12/24/2022]
Abstract
Endoplasmic reticulum (ER) is the site of protein synthesis, protein folding, maintainance of calcium homeostasis, synthesis of lipids and sterols. Genetic or environmental insults can alter its function generating ER stress. ER senses stress mainly by three stress sensor pathways, namely protein kinase R-like endoplasmic reticulum kinase-eukaryotic translation-initiation factor 2α, inositol-requiring enzyme 1α-X-box-binding protein 1 and activating transcription factor 6-CREBH, which induce unfolded protein responses (UPR) after the recognition of stress. Recent studies have demonstrated that ER stress and UPR signaling are involved in cancer, metabolic disorders, inflammatory diseases, osteoporosis and neurodegenerative diseases. However, the precise knowledge regarding involvement of ER stress in different disease processes is still debatable. Here we discuss the possible role of ER stress in various disorders on the basis of existing literature. An attempt has also been made to highlight the present knowledge of this field which may help to elucidate and conjure basic mechanisms and novel insights into disease processes which could assist in devising better future diagnostic and therapeutic strategies.
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Affiliation(s)
- Abbas Ali Mahdi
- Department of Biochemistry, King George's Medical University, Lucknow, 226003 Uttar Pradesh India
| | | | - Arshiya Parveen
- Department of Biochemistry, King George's Medical University, Lucknow, 226003 Uttar Pradesh India
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66
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Llanos P, Contreras-Ferrat A, Barrientos G, Valencia M, Mears D, Hidalgo C. Glucose-Dependent Insulin Secretion in Pancreatic β-Cell Islets from Male Rats Requires Ca2+ Release via ROS-Stimulated Ryanodine Receptors. PLoS One 2015; 10:e0129238. [PMID: 26046640 PMCID: PMC4457734 DOI: 10.1371/journal.pone.0129238] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 05/06/2015] [Indexed: 12/03/2022] Open
Abstract
Glucose-stimulated insulin secretion (GSIS) from pancreatic β-cells requires an increase in intracellular free Ca2+ concentration ([Ca2+]). Glucose uptake into β-cells promotes Ca2+ influx and reactive oxygen species (ROS) generation. In other cell types, Ca2+ and ROS jointly induce Ca2+ release mediated by ryanodine receptor (RyR) channels. Therefore, we explored here if RyR-mediated Ca2+ release contributes to GSIS in β-cell islets isolated from male rats. Stimulatory glucose increased islet insulin secretion, and promoted ROS generation in islets and dissociated β-cells. Conventional PCR assays and immunostaining confirmed that β-cells express RyR2, the cardiac RyR isoform. Extended incubation of β-cell islets with inhibitory ryanodine suppressed GSIS; so did the antioxidant N-acetyl cysteine (NAC), which also decreased insulin secretion induced by glucose plus caffeine. Inhibitory ryanodine or NAC did not affect insulin secretion induced by glucose plus carbachol, which engages inositol 1,4,5-trisphosphate receptors. Incubation of islets with H2O2 in basal glucose increased insulin secretion 2-fold. Inhibitory ryanodine significantly decreased H2O2-stimulated insulin secretion and prevented the 4.5-fold increase of cytoplasmic [Ca2+] produced by incubation of dissociated β-cells with H2O2. Addition of stimulatory glucose or H2O2 (in basal glucose) to β-cells disaggregated from islets increased RyR2 S-glutathionylation to similar levels, measured by a proximity ligation assay; in contrast, NAC significantly reduced the RyR2 S-glutathionylation increase produced by stimulatory glucose. We propose that RyR2-mediated Ca2+ release, induced by the concomitant increases in [Ca2+] and ROS produced by stimulatory glucose, is an essential step in GSIS.
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Affiliation(s)
- Paola Llanos
- Institute for Research in Dental Sciences, Facultad de Odontología, Universidad de Chile, Santiago, Chile
- Center of Molecular Studies of the Cell, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Ariel Contreras-Ferrat
- Institute for Research in Dental Sciences, Facultad de Odontología, Universidad de Chile, Santiago, Chile
- Center of Molecular Studies of the Cell, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Genaro Barrientos
- Physiology and Biophysics Program, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Marco Valencia
- Center of Molecular Studies of the Cell, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - David Mears
- Center of Molecular Studies of the Cell, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Human Genetics Program, Institute of Biomedical Sciences, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Cecilia Hidalgo
- Center of Molecular Studies of the Cell, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Physiology and Biophysics Program, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Biomedical Neuroscience Institute, Facultad de Medicina, Universidad de Chile, Santiago, Chile
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67
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Ferreira ST, Lourenco MV, Oliveira MM, De Felice FG. Soluble amyloid-β oligomers as synaptotoxins leading to cognitive impairment in Alzheimer's disease. Front Cell Neurosci 2015; 9:191. [PMID: 26074767 PMCID: PMC4443025 DOI: 10.3389/fncel.2015.00191] [Citation(s) in RCA: 240] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 04/30/2015] [Indexed: 12/22/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia in the elderly, and affects millions of people worldwide. As the number of AD cases continues to increase in both developed and developing countries, finding therapies that effectively halt or reverse disease progression constitutes a major research and public health challenge. Since the identification of the amyloid-β peptide (Aβ) as the major component of the amyloid plaques that are characteristically found in AD brains, a major effort has aimed to determine whether and how Aβ leads to memory loss and cognitive impairment. A large body of evidence accumulated in the past 15 years supports a pivotal role of soluble Aβ oligomers (AβOs) in synapse failure and neuronal dysfunction in AD. Nonetheless, a number of basic questions, including the exact molecular composition of the synaptotoxic oligomers, the identity of the receptor(s) to which they bind, and the signaling pathways that ultimately lead to synapse failure, remain to be definitively answered. Here, we discuss recent advances that have illuminated our understanding of the chemical nature of the toxic species and the deleterious impact they have on synapses, and have culminated in the proposal of an Aβ oligomer hypothesis for Alzheimer’s pathogenesis. We also highlight outstanding questions and challenges in AD research that should be addressed to allow translation of research findings into effective AD therapies.
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Affiliation(s)
- Sergio T Ferreira
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro Rio de Janeiro, RJ, Brazil ; Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro Rio de Janeiro, RJ, Brazil
| | - Mychael V Lourenco
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro Rio de Janeiro, RJ, Brazil
| | - Mauricio M Oliveira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro Rio de Janeiro, RJ, Brazil
| | - Fernanda G De Felice
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro Rio de Janeiro, RJ, Brazil
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68
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Arrázola MS, Silva-Alvarez C, Inestrosa NC. How the Wnt signaling pathway protects from neurodegeneration: the mitochondrial scenario. Front Cell Neurosci 2015; 9:166. [PMID: 25999816 PMCID: PMC4419851 DOI: 10.3389/fncel.2015.00166] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 04/14/2015] [Indexed: 12/12/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common neurodegenerative disorder and is characterized by progressive memory loss and cognitive decline. One of the hallmarks of AD is the overproduction of amyloid-beta aggregates that range from the toxic soluble oligomer (Aβo) form to extracellular accumulations in the brain. Growing evidence indicates that mitochondrial dysfunction is a common feature of neurodegenerative diseases and is observed at an early stage in the pathogenesis of AD. Reports indicate that mitochondrial structure and function are affected by Aβo and can trigger neuronal cell death. Mitochondria are highly dynamic organelles, and the balance between their fusion and fission processes is essential for neuronal function. Interestingly, in AD, the process known as “mitochondrial dynamics” is also impaired by Aβo. On the other hand, the activation of the Wnt signaling pathway has an essential role in synaptic maintenance and neuronal functions, and its deregulation has also been implicated in AD. We have demonstrated that canonical Wnt signaling, through the Wnt3a ligand, prevents the permeabilization of mitochondrial membranes through the inhibition of the mitochondrial permeability transition pore (mPTP), induced by Aβo. In addition, we showed that non-canonical Wnt signaling, through the Wnt5a ligand, protects mitochondria from fission-fusion alterations in AD. These results suggest new approaches by which different Wnt signaling pathways protect neurons in AD, and support the idea that mitochondria have become potential therapeutic targets for the treatment of neurodegenerative disorders. Here we discuss the neuroprotective role of the canonical and non-canonical Wnt signaling pathways in AD and their differential modulation of mitochondrial processes, associated with mitochondrial dysfunction and neurodegeneration.
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Affiliation(s)
- Macarena S Arrázola
- Facultad de Ciencias Biológicas, Departamento de Biología Celular y Molecular, Centro de Envejecimiento y Regeneración (CARE), Pontificia Universidad Católica de Chile Santiago, Chile
| | - Carmen Silva-Alvarez
- Facultad de Ciencias Biológicas, Departamento de Biología Celular y Molecular, Centro de Envejecimiento y Regeneración (CARE), Pontificia Universidad Católica de Chile Santiago, Chile
| | - Nibaldo C Inestrosa
- Facultad de Ciencias Biológicas, Departamento de Biología Celular y Molecular, Centro de Envejecimiento y Regeneración (CARE), Pontificia Universidad Católica de Chile Santiago, Chile ; Center for Healthy Brain Aging, School of Psychiatry, Faculty of Medicine, University of New South Wales Sydney, NSW, Australia ; Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes Punta Arenas, Chile ; Centro UC Síndrome de Down, Pontificia Universidad Católica de Chile Santiago, Chile
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69
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The role of type 2 diabetes in neurodegeneration. Neurobiol Dis 2015; 84:22-38. [PMID: 25926349 DOI: 10.1016/j.nbd.2015.04.008] [Citation(s) in RCA: 185] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 04/18/2015] [Accepted: 04/21/2015] [Indexed: 02/07/2023] Open
Abstract
A growing body of evidence links type-2 diabetes (T2D) with dementia and neurodegenerative diseases such as Alzheimer's disease (AD). AD is the most common form of dementia and is characterised neuropathologically by the accumulation of extracellular beta amyloid (Aβ) peptide aggregates and intracellular hyper-phosphorylated tau protein, which are thought to drive and/or accelerate inflammatory and oxidative stress processes leading to neurodegeneration. Although the precise mechanism remains unclear, T2D can exacerbate these neurodegenerative processes. Brain atrophy, reduced cerebral glucose metabolism and CNS insulin resistance are features of both AD and T2D. Cell culture and animal studies have indicated that the early accumulation of Aβ may play a role in CNS insulin resistance and impaired insulin signalling. From the viewpoint of insulin resistance and impaired insulin signalling in the brain, these are also believed to initiate other aspects of brain injury, including inflammatory and oxidative stress processes. Here we review the clinical and experimental pieces of evidence that link these two chronic diseases of ageing, and discuss underlying mechanisms. The evaluation of treatments for the management of diabetes in preclinical, and clinical studies and trials for AD will also be discussed.
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70
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Lourenco MV, Ferreira ST, De Felice FG. Neuronal stress signaling and eIF2α phosphorylation as molecular links between Alzheimer's disease and diabetes. Prog Neurobiol 2015; 129:37-57. [PMID: 25857551 DOI: 10.1016/j.pneurobio.2015.03.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 03/10/2015] [Accepted: 03/29/2015] [Indexed: 12/22/2022]
Abstract
Mounting evidence from clinical, epidemiological, neuropathology and preclinical studies indicates that mechanisms similar to those leading to peripheral metabolic deregulation in metabolic disorders, such as diabetes and obesity, take place in the brains of Alzheimer's disease (AD) patients. These include pro-inflammatory mechanisms, brain metabolic stress and neuronal insulin resistance. From a molecular and cellular perspective, recent progress has been made in unveiling novel pathways that act in an orchestrated way to cause neuronal damage and cognitive decline in AD. These pathways converge to the activation of neuronal stress-related protein kinases and excessive phosphorylation of eukaryotic translation initiation factor 2α (eIF2α-P), which plays a key role in control of protein translation, culminating in synapse dysfunction and memory loss. eIF2α-P signaling thus links multiple neuronal stress pathways to impaired neuronal function and neurodegeneration. Here, we present a critical analysis of recently discovered molecular mechanisms underlying impaired brain insulin signaling and metabolic stress, with emphasis on the role of stress kinase/eIF2α-P signaling as a hub that promotes brain and behavioral impairments in AD. Because very similar mechanisms appear to operate in peripheral metabolic deregulation in T2D and in brain defects in AD, we discuss the concept that targeting defective brain insulin signaling and neuronal stress mechanisms with anti-diabetes agents may be an attractive approach to fight memory decline in AD. We conclude by raising core questions that remain to be addressed toward the development of much needed therapeutic approaches for AD.
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Affiliation(s)
- Mychael V Lourenco
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil.
| | - Sergio T Ferreira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil; Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - Fernanda G De Felice
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil.
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71
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Aβ42 oligomers selectively disrupt neuronal calcium release. Neurobiol Aging 2015; 36:877-85. [DOI: 10.1016/j.neurobiolaging.2014.10.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 10/09/2014] [Accepted: 10/14/2014] [Indexed: 12/30/2022]
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Adasme T, Paula-Lima A, Hidalgo C. Inhibitory ryanodine prevents ryanodine receptor-mediated Ca²⁺ release without affecting endoplasmic reticulum Ca²⁺ content in primary hippocampal neurons. Biochem Biophys Res Commun 2015; 458:57-62. [PMID: 25623539 DOI: 10.1016/j.bbrc.2015.01.065] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 01/15/2015] [Indexed: 10/24/2022]
Abstract
Ryanodine is a cell permeant plant alkaloid that binds selectively and with high affinity to ryanodine receptor (RyR) Ca(2+) release channels. Sub-micromolar ryanodine concentrations activate RyR channels while micromolar concentrations are inhibitory. Several reports indicate that neuronal synaptic plasticity, learning and memory require RyR-mediated Ca(2+)-release, which is essential for muscle contraction. The use of micromolar (inhibitory) ryanodine represents a common strategy to suppress RyR activity in neuronal cells: however, micromolar ryanodine promotes RyR-mediated Ca(2+) release and endoplasmic reticulum Ca(2+) depletion in muscle cells. Information is lacking in this regard in neuronal cells; hence, we examined here if addition of inhibitory ryanodine elicited Ca(2+) release in primary hippocampal neurons, and if prolonged incubation of primary hippocampal cultures with inhibitory ryanodine affected neuronal ER calcium content. Our results indicate that inhibitory ryanodine does not cause Ca(2+) release from the ER in primary hippocampal neurons, even though ryanodine diffusion should produce initially low intracellular concentrations, within the RyR activation range. Moreover, neurons treated for 1 h with inhibitory ryanodine had comparable Ca(2+) levels as control neurons. These combined findings imply that prolonged incubation with inhibitory ryanodine, which effectively abolishes RyR-mediated Ca(2+) release, preserves ER Ca(2+) levels and thus constitutes a sound strategy to suppress neuronal RyR function.
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Affiliation(s)
- Tatiana Adasme
- Biomedical Neuroscience Institute and Centro de Estudios Moleculares de la Célula, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Andrea Paula-Lima
- Biomedical Neuroscience Institute and Centro de Estudios Moleculares de la Célula, Faculty of Medicine, Universidad de Chile, Santiago, Chile; Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de Chile, Santiago, Chile
| | - Cecilia Hidalgo
- Biomedical Neuroscience Institute and Centro de Estudios Moleculares de la Célula, Faculty of Medicine, Universidad de Chile, Santiago, Chile; Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Chile.
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73
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Gan KJ, Silverman MA. Dendritic and axonal mechanisms of Ca2+ elevation impair BDNF transport in Aβ oligomer-treated hippocampal neurons. Mol Biol Cell 2015; 26:1058-71. [PMID: 25609087 PMCID: PMC4357506 DOI: 10.1091/mbc.e14-12-1612] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Intracellular Ca2+ dysregulation and transport disruption precede cell death in Alzheimer's disease. Mechanisms of AβO-induced Ca2+ elevation are identified that regulate the onset, severity, and spatiotemporal progression of BDNF transport defects. The results challenge dogmatic views on mechanisms of AβO toxicity and subcellular sites of action. Disruption of fast axonal transport (FAT) and intracellular Ca2+ dysregulation are early pathological events in Alzheimer's disease (AD). Amyloid-β oligomers (AβOs), a causative agent of AD, impair transport of BDNF independent of tau by nonexcitotoxic activation of calcineurin (CaN). Ca2+-dependent mechanisms that regulate the onset, severity, and spatiotemporal progression of BDNF transport defects from dendritic and axonal AβO binding sites are unknown. Here we show that BDNF transport defects in dendrites and axons are induced simultaneously but exhibit different rates of decline. The spatiotemporal progression of FAT impairment correlates with Ca2+ elevation and CaN activation first in dendrites and subsequently in axons. Although many axonal pathologies have been described in AD, studies have primarily focused only on the dendritic effects of AβOs despite compelling reports of presynaptic AβOs in AD models and patients. Indeed, we observe that dendritic CaN activation converges on Ca2+ influx through axonal voltage-gated Ca2+ channels to impair FAT. Finally, FAT defects are prevented by dantrolene, a clinical compound that reduces Ca2+ release from the ER. This work establishes a novel role for Ca2+ dysregulation in BDNF transport disruption and tau-independent Aβ toxicity in early AD.
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Affiliation(s)
- Kathlyn J Gan
- Department of Molecular Biology and Biochemistry and
| | - Michael A Silverman
- Department of Molecular Biology and Biochemistry and Department of Biological Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada Brain Research Centre, University of British Columbia, Vancouver, BC V6T 2B5, Canada
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Park J, Choi H, Min JS, Kim B, Lee SR, Yun JW, Choi MS, Chang KT, Lee DS. Loss of mitofusin 2 links beta-amyloid-mediated mitochondrial fragmentation and Cdk5-induced oxidative stress in neuron cells. J Neurochem 2015; 132:687-702. [PMID: 25359615 DOI: 10.1111/jnc.12984] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 10/16/2014] [Accepted: 10/22/2014] [Indexed: 12/12/2022]
Abstract
Mitochondrial dysfunction is implicated in age-related degenerative disorders such as Alzheimer's disease (AD). Maintenance of mitochondrial dynamics is essential for regulating mitochondrial function. Aβ oligomers (AβOs), the typical cause of AD, lead to mitochondrial dysfunction and neuronal loss. AβOs have been shown to induce mitochondrial fragmentation, and their inhibition suppresses mitochondrial dysfunction and neuronal cell death. Oxidative stress is one of the earliest hallmarks of AD. Cyclin-dependent kinase 5 (Cdk5) may cause oxidative stress by disrupting the antioxidant system, including Prx2. Cdk5 is also regarded as a modulator of mitochondrial fission; however, a precise mechanistic link between Cdk5 and mitochondrial dynamics is lacking. We estimated mitochondrial morphology and alterations in mitochondrial morphology-related proteins in Neuro-2a (N2a) cells stably expressing the Swedish mutation of amyloid precursor protein (APP), which is known to increase AβO production. We demonstrated that mitochondrial fragmentation by AβOs accompanies reduced mitofusin 1 and 2 (Mfn1/2) levels. Interestingly, the Cdk5 pathway, including phosphorylation of the Prx2-related oxidative stress, has been shown to regulate Mfn1 and Mfn2 levels. Furthermore, Mfn2, but not Mfn1, over-expression significantly inhibits the AβO-mediated cell death pathway. Therefore, these results indicate that AβO-mediated oxidative stress triggers mitochondrial fragmentation via decreased Mfn2 expression by activating Cdk5-induced Prx2 phosphorylation. Mitochondrial fragmentation induced by amyloid-beta oligomer (AβOs) which is generated from the Swedish mutation of amyloid precursor protein (APP) accompanies reduced Mfn1/2 levels. Interestingly, the Cdk5 pathway, including phosphorylation of the Prx2-related oxidative stress, has been shown to regulate Mfn1/2. Furthermore, Mfn2 over-expression significantly inhibits the AβO-mediated neuronal cells death pathway, but not Mfn1 over-expression. Therefore, these results indicate that AβO-mediated oxidative stress triggers mitochondrial fragmentation via decreased Mfn2 expression by activating Cdk5-induced Prx2 phosphorylation. ATP, adenosine triphosphate; Bax, Bcl-2-associated X protein; Bcl-2, B-cell lymphoma 2; Cdk5, Cyclin-dependent kinase; Cyt C, cytochrome C; Mfn2, mitofusin 2; Prx2, peroxiredoxin 2; ROS, reactive oxygen species.
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Affiliation(s)
- Junghyung Park
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Korea
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De Felice FG, Lourenco MV, Ferreira ST. How does brain insulin resistance develop in Alzheimer's disease? Alzheimers Dement 2014; 10:S26-32. [PMID: 24529521 DOI: 10.1016/j.jalz.2013.12.004] [Citation(s) in RCA: 229] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 12/05/2013] [Indexed: 02/08/2023]
Abstract
Compelling preclinical and clinical evidence supports a pathophysiological connection between Alzheimer's disease (AD) and diabetes. Altered metabolism, inflammation, and insulin resistance are key pathological features of both diseases. For many years, it was generally considered that the brain was insensitive to insulin, but it is now accepted that this hormone has central neuromodulatory functions, including roles in learning and memory, that are impaired in AD. However, until recently, the molecular mechanisms accounting for brain insulin resistance in AD have remained elusive. Here, we review recent evidence that sheds light on how brain insulin dysfunction is initiated at a molecular level and why abnormal insulin signaling culminates in synaptic failure and memory decline. We also discuss the cellular basis underlying the beneficial effects of stimulation of brain insulin signaling on cognition. Discoveries summarized here provide pathophysiological background for identification of novel molecular targets and for development of alternative therapeutic approaches in AD.
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Affiliation(s)
- Fernanda G De Felice
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
| | - Mychael V Lourenco
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Sergio T Ferreira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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76
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Maggio N, Vlachos A. Synaptic plasticity at the interface of health and disease: New insights on the role of endoplasmic reticulum intracellular calcium stores. Neuroscience 2014; 281:135-46. [PMID: 25264032 DOI: 10.1016/j.neuroscience.2014.09.041] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/17/2014] [Accepted: 09/18/2014] [Indexed: 10/24/2022]
Abstract
Work from the past 40years has unraveled a wealth of information on the cellular and molecular mechanisms underlying synaptic plasticity and their relevance in physiological brain function. At the same time, it has been recognized that a broad range of neurological diseases may be accompanied by severe alterations in synaptic plasticity, i.e., 'maladaptive synaptic plasticity', which could initiate and sustain the remodeling of neuronal networks under pathological conditions. Nonetheless, our current knowledge on the specific contribution and interaction of distinct forms of synaptic plasticity (including metaplasticity and homeostatic plasticity) in the context of pathological brain states remains limited. This review focuses on recent experimental evidence, which highlights the fundamental role of endoplasmic reticulum-mediated Ca(2+) signals in modulating the duration, direction, extent and type of synaptic plasticity. We discuss the possibility that intracellular Ca(2+) stores may regulate synaptic plasticity and hence behavioral and cognitive functions at the interface between physiology and pathology.
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Affiliation(s)
- N Maggio
- Talpiot Medical Leadership Program, Department of Neurology, The Chaim Sheba Medical Center, 52621 Tel HaShomer, Israel
| | - A Vlachos
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt, 60590 Frankfurt, Germany.
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77
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Zolezzi JM, Inestrosa NC. Brain metabolite clearance: impact on Alzheimer's disease. Metab Brain Dis 2014; 29:553-61. [PMID: 24664180 DOI: 10.1007/s11011-014-9527-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 03/07/2014] [Indexed: 12/13/2022]
Abstract
Alzheimer's Disease (AD) is a complex neurodegenerative disorder often associated with aging and characterized by several critical molecular changes that take place in the brain. Among the molecular hallmarks of AD, increased levels of amyloid β-peptide (Aβ) and the subsequent Aβ-derived damage are the most well-studied factors; however, despite the large amounts of effort and resources devoted to the study of AD and AD pathophysiology, the scientific community still awaits therapeutic alternatives capable of ensuring a better outcome for AD patients. In 2012, Cramer et al. (Science 335:1503-1506 2012) astonished the scientific community by rescuing behavioral and cognitive impairments in AD mouse models via oral administration of bexarotene, a drug used to treat some types of skin cancer. Moreover, these authors demonstrated that bexarotene, a retinoid X receptor (RXR) agonist, exerts major effects on Aβ levels, mainly through increased apolipoprotein E (ApoE) expression. Apart from the valid questions addressed in Cramer's work, only a few attempts have been made to explain the effects of bexarotene. Most of these explanations have been solely based on the ability of bexarotene to reduce Aβ levels and not on the mechanisms that lead to such a reduction. Although it is well known that an imbalance in the Aβ production/excretion rate is the basis of increased Aβ levels in AD, no further explanations have been proposed to address the potential involvement of the blood-brain barrier (BBB), a critical Aβ-clearance structure, in the bexarotene-mediated effects. Moreover, no attempt has been made to explain how the different effects observed after bexarotene administration are connected to each other. Based on current information and on our own experience with nuclear receptors (NR), we offer new perspectives on the mechanisms of bexarotene action, which should help to improve our knowledge of NRs.
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Affiliation(s)
- Juan M Zolezzi
- Departamento de Biología, Facultad de Ciencias, Universidad de Tarapacá, Gral. Velásquez, 1775, Arica, Chile
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78
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Paula-Lima AC, Adasme T, Hidalgo C. Contribution of Ca2+ release channels to hippocampal synaptic plasticity and spatial memory: potential redox modulation. Antioxid Redox Signal 2014; 21:892-914. [PMID: 24410659 DOI: 10.1089/ars.2013.5796] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
SIGNIFICANCE Memory is an essential human cognitive function. Consequently, to unravel the cellular and molecular mechanisms responsible for the synaptic plasticity events underlying memory formation, storage and loss represents a major challenge of present-day neuroscience. RECENT ADVANCES This review article first describes the wide-ranging functions played by intracellular Ca2+ signals in the activity-dependent synaptic plasticity processes underlying hippocampal spatial memory, and next, it focuses on how the endoplasmic reticulum Ca2+ release channels, the ryanodine receptors, and the inositol 1,4,5-trisphosphate receptors contribute to these processes. We present a detailed examination of recent evidence supporting the key role played by Ca2+ release channels in synaptic plasticity, including structural plasticity, and the formation/consolidation of spatial memory in the hippocampus. CRITICAL ISSUES Changes in cellular oxidative state particularly affect the function of Ca2+ release channels and alter hippocampal synaptic plasticity and the associated memory processes. Emphasis is placed in this review on how defective Ca2+ release, presumably due to increased levels of reactive oxygen species, may cause the hippocampal functional defects that are associated to aging and Alzheimer's disease (AD). FUTURE DIRECTIONS Additional studies should examine the precise molecular mechanisms by which Ca2+ release channels contribute to hippocampal synaptic plasticity and spatial memory formation/consolidation. Future studies should test whether redox-modified Ca2+ release channels contribute toward generating the intracellular Ca2+ signals required for sustained synaptic plasticity and hippocampal spatial memory, and whether loss of redox balance and oxidative stress, by altering Ca2+ release channel function, presumably contribute to the abnormal memory processes that occur during aging and AD.
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Affiliation(s)
- Andrea C Paula-Lima
- 1 Faculty of Dentistry, Institute for Research in Dental Sciences, Universidad de Chile , Santiago, Chile
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79
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Zolezzi JM, Bastías-Candia S, Santos MJ, Inestrosa NC. Alzheimer's disease: relevant molecular and physiopathological events affecting amyloid-β brain balance and the putative role of PPARs. Front Aging Neurosci 2014; 6:176. [PMID: 25120477 PMCID: PMC4112937 DOI: 10.3389/fnagi.2014.00176] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 07/03/2014] [Indexed: 12/02/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of age-related dementia. With the expected aging of the human population, the estimated morbidity of AD suggests a critical upcoming health problem. Several lines of research are focused on understanding AD pathophysiology, and although the etiology of the disease remains a matter of intense debate, increased brain levels of amyloid-β (Aβ) appear to be a critical event in triggering a wide range of molecular alterations leading to AD. It has become evident in recent years that an altered balance between production and clearance is responsible for the accumulation of brain Aβ. Moreover, Aβ clearance is a complex event that involves more than neurons and microglia. The status of the blood-brain barrier (BBB) and choroid plexus, along with hepatic functionality, should be considered when Aβ balance is addressed. Furthermore, it has been proposed that exposure to sub-toxic concentrations of metals, such as copper, could both directly affect these secondary structures and act as a seeding or nucleation core that facilitates Aβ aggregation. Recently, we have addressed peroxisomal proliferator-activated receptors (PPARs)-related mechanisms, including the direct modulation of mitochondrial dynamics through the PPARγ-coactivator-1α (PGC-1α) axis and the crosstalk with critical aging- and neurodegenerative-related cellular pathways. In the present review, we revise the current knowledge regarding the molecular aspects of Aβ production and clearance and provide a physiological context that gives a more complete view of this issue. Additionally, we consider the different structures involved in AD-altered Aβ brain balance, which could be directly or indirectly affected by a nuclear receptor (NR)/PPAR-related mechanism.
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Affiliation(s)
- Juan M Zolezzi
- Laboratorio de Biología Celular y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Tarapacá Arica, Chile
| | - Sussy Bastías-Candia
- Laboratorio de Biología Celular y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Tarapacá Arica, Chile
| | - Manuel J Santos
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Nibaldo C Inestrosa
- Centro de Envejecimiento y Regeneración (CARE), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile Santiago, Chile ; Centre for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South Wales Sydney, NSW, Australia ; Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes Punta Arenas, Chile
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80
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Segal M, Korkotian E. Endoplasmic reticulum calcium stores in dendritic spines. Front Neuroanat 2014; 8:64. [PMID: 25071469 PMCID: PMC4089118 DOI: 10.3389/fnana.2014.00064] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 06/23/2014] [Indexed: 12/14/2022] Open
Abstract
Despite decades of research, the role of calcium stores in dendritic spines structure, function and plasticity is still debated. The reasons for this may have to do with the multitude of overlapping calcium handling machineries in the neuron, including stores, voltage and ligand gated channels, pumps and transporters. Also, different cells in the brain are endowed with calcium stores that are activated by different receptor types, and their differential compartmentalization in dendrites, spines and presynaptic terminals complicates their analysis. In the present review we address several key issues, including the role of calcium stores in synaptic plasticity, their role during development, in stress and in neurodegenerative diseases. Apparently, there is increasing evidence for a crucial role of calcium stores, especially of the ryanodine species, in synaptic plasticity and neuronal survival.
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Affiliation(s)
- Menahem Segal
- Department of Neurobiology, The Weizman Institute Rehovot, Israel
| | - Eduard Korkotian
- Department of Neurobiology, The Weizman Institute Rehovot, Israel
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81
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Elevated risk of type 2 diabetes for development of Alzheimer disease: a key role for oxidative stress in brain. Biochim Biophys Acta Mol Basis Dis 2014; 1842:1693-706. [PMID: 24949886 DOI: 10.1016/j.bbadis.2014.06.010] [Citation(s) in RCA: 263] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 06/05/2014] [Accepted: 06/09/2014] [Indexed: 12/23/2022]
Abstract
Alzheimer disease (AD) is the most common form of dementia among the elderly and is characterized by progressive loss of memory and cognition. Epidemiological data show that the incidence of AD increases with age and doubles every 5 years after 65 years of age. From a neuropathological point of view, amyloid-β-peptide (Aβ) leads to senile plaques, which, together with hyperphosphorylated tau-based neurofibrillary tangles and synapse loss, are the principal pathological hallmarks of AD. Aβ is associated with the formation of reactive oxygen (ROS) and nitrogen (RNS) species, and induces calcium-dependent excitotoxicity, impairment of cellular respiration, and alteration of synaptic functions associated with learning and memory. Oxidative stress was found to be associated with type 2 diabetes mellitus (T2DM), which (i) represents another prevalent disease associated with obesity and often aging, and (ii) is considered to be a risk factor for AD development. T2DM is characterized by high blood glucose levels resulting from increased hepatic glucose production, impaired insulin production and peripheral insulin resistance, which close resemble to the brain insulin resistance observed in AD patients. Furthermore, growing evidence suggests that oxidative stress plays a pivotal role in the development of insulin resistance and vice versa. This review article provides molecular aspects and the pharmacological approaches from both preclinical and clinical data interpreted from the point of view of oxidative stress with the aim of highlighting progresses in this field.
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82
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Del Prete D, Checler F, Chami M. Ryanodine receptors: physiological function and deregulation in Alzheimer disease. Mol Neurodegener 2014; 9:21. [PMID: 24902695 PMCID: PMC4063224 DOI: 10.1186/1750-1326-9-21] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 05/18/2014] [Indexed: 12/21/2022] Open
Abstract
Perturbed Endoplasmic Reticulum (ER) calcium (Ca2+) homeostasis emerges as a central player in Alzheimer disease (AD). Accordingly, different studies have reported alterations of the expression and the function of Ryanodine Receptors (RyR) in human AD-affected brains, in cells expressing familial AD-linked mutations on the β amyloid precursor protein (βAPP) and presenilins (the catalytic core in γ-secretase complexes cleaving the βAPP, thereby generating amyloid β (Aβ) peptides), as well as in the brain of various transgenic AD mice models. Data converge to suggest that RyR expression and function alteration are associated to AD pathogenesis through the control of: i) βAPP processing and Aβ peptide production, ii) neuronal death; iii) synaptic function; and iv) memory and learning abilities. In this review, we document the network of evidences suggesting that RyR could play a complex dual "compensatory/protective versus pathogenic" role contributing to the setting of histopathological lesions and synaptic deficits that are associated with the disease stages. We also discuss the possible mechanisms underlying RyR expression and function alterations in AD. Finally, we review recent publications showing that drug-targeting blockade of RyR and genetic manipulation of RyR reduces Aβ production, stabilizes synaptic transmission, and prevents learning and memory deficits in various AD mouse models. Chemically-designed RyR "modulators" could therefore be envisioned as new therapeutic compounds able to delay or block the progression of AD.
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Affiliation(s)
| | - Frédéric Checler
- Université de Nice Sophia Antipolis, IPMC, Sophia Antipolis, Nice, F-06560 Valbonne, France.
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83
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Mustafa Rizvi SH, Parveen A, Verma AK, Ahmad I, Arshad M, Mahdi AA. Aluminium induced endoplasmic reticulum stress mediated cell death in SH-SY5Y neuroblastoma cell line is independent of p53. PLoS One 2014; 9:e98409. [PMID: 24878590 PMCID: PMC4039480 DOI: 10.1371/journal.pone.0098409] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 04/29/2014] [Indexed: 11/18/2022] Open
Abstract
Aluminium (Al) is the third most abundant element in the earth’s crust and its compounds are used in the form of house hold utensils, medicines and in antiperspirant etc. Increasing number of evidences suggest the involvement of Al+3 ions in a variety of neurodegenerative disorders including Alzheimer’s disease. Here, we have attempted to investigate the role of Al in endoplasmic reticulum stress and the regulation of p53 during neuronal apoptosis using neuroblastoma cell line. We observed that Al caused oxidative stress by increasing ROS production and intracellular calcium levels together with depletion of intracellular GSH levels. We also studied modulation of key pro- and anti-apoptotic proteins and found significant alterations in the levels of Nrf2, NQO1, pAKT, p21, Bax, Bcl2, Aβ1-40 and Cyt c together with increase in endoplasmic reticulum (ER) stress related proteins like CHOP and caspase 12. However, with respect to the role of p53, we observed downregulation of its transcript as well as protein levels while analysis of its ubiquitination status revealed no significant changes. Not only did Al increase the activities of caspase 9, caspase 12 and caspase 3, but, by the use of peptide inhibitors of specific and pan-caspases, we observed significant protection against neuronal cell death upon inhibition of caspase 12, demonstrating the prominent role of endoplasmic reticulum stress generated responses in Al toxicity. Overall our findings suggest that Al induces ER stress and ROS generation which compromises the antioxidant defenses of neuronal cells thereby promoting neuronal apoptosis in p53 independent pathway.
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Affiliation(s)
| | - Arshiya Parveen
- Department of Biochemistry, King George's Medical University, Lucknow, Uttar Pradesh, India
| | - Anoop K Verma
- Forensic Medicine & Toxicology, King George's Medical University, Lucknow, Uttar Pradesh, India
| | - Iqbal Ahmad
- Fibre Toxicology Division, CSIR- Indian Institute of Toxicology Research, Lucknow, Uttar Pradesh, India
| | - Md Arshad
- Department of Zoology, Lucknow University, Lucknow, Uttar Pradesh, India
| | - Abbas Ali Mahdi
- Department of Biochemistry, King George's Medical University, Lucknow, Uttar Pradesh, India
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84
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Sanmartín CD, Paula-Lima AC, García A, Barattini P, Hartel S, Núñez MT, Hidalgo C. Ryanodine receptor-mediated Ca(2+) release underlies iron-induced mitochondrial fission and stimulates mitochondrial Ca(2+) uptake in primary hippocampal neurons. Front Mol Neurosci 2014; 7:13. [PMID: 24653672 PMCID: PMC3949220 DOI: 10.3389/fnmol.2014.00013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 02/03/2014] [Indexed: 01/11/2023] Open
Abstract
Mounting evidence indicates that iron accumulation impairs brain function. We have reported previously that addition of sub-lethal concentrations of iron to primary hippocampal neurons produces Ca2+ signals and promotes cytoplasmic generation of reactive oxygen species. These Ca2+ signals, which emerge within seconds after iron addition, arise mostly from Ca2+ release through the redox-sensitive ryanodine receptor (RyR) channels present in the endoplasmic reticulum. We have reported also that addition of synaptotoxic amyloid-β oligomers to primary hippocampal neurons stimulates RyR-mediated Ca2+ release, generating long-lasting Ca2+ signals that activate Ca2+-sensitive cellular effectors and promote the disruption of the mitochondrial network. Here, we describe that 24 h incubation of primary hippocampal neurons with iron enhanced agonist-induced RyR-mediated Ca2+ release and promoted mitochondrial network fragmentation in 43% of neurons, a response significantly prevented by RyR inhibition and by the antioxidant agent N-acetyl-L-cysteine. Stimulation of RyR-mediated Ca2+ release by a RyR agonist promoted mitochondrial Ca2+ uptake in control neurons and in iron-treated neurons that displayed non-fragmented mitochondria, but not in neurons with fragmented mitochondria. Yet, the global cytoplasmic Ca2+ increase induced by the Ca2+ ionophore ionomycin prompted significant mitochondrial Ca2+ uptake in neurons with fragmented mitochondria, indicating that fragmentation did not prevent mitochondrial Ca2+ uptake but presumably decreased the functional coupling between RyR-mediated Ca2+ release and the mitochondrial Ca2+ uniporter. Taken together, our results indicate that stimulation of redox-sensitive RyR-mediated Ca2+ release by iron causes significant neuronal mitochondrial fragmentation, which presumably contributes to the impairment of neuronal function produced by iron accumulation.
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Affiliation(s)
- Carol D Sanmartín
- Center for Molecular Studies of the Cell, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile Santiago, Chile ; Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile Santiago, Chile
| | - Andrea C Paula-Lima
- Center for Molecular Studies of the Cell, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile Santiago, Chile ; Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile Santiago, Chile ; Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de Chile Santiago, Chile
| | - Alejandra García
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile Santiago, Chile
| | - Pablo Barattini
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile Santiago, Chile
| | - Steffen Hartel
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile Santiago, Chile ; Laboratory of Scientific Image Processing, Anatomy and Developmental Biology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile Santiago, Chile
| | - Marco T Núñez
- Department of Biology, Faculty of Sciences and Research Ring on Oxidative Stress in the Nervous System, Universidad de Chile Santiago, Chile
| | - Cecilia Hidalgo
- Center for Molecular Studies of the Cell, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile Santiago, Chile ; Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile Santiago, Chile ; Physiology and Biophysics Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile Santiago, Chile
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85
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Rush T, Buisson A. Reciprocal disruption of neuronal signaling and Aβ production mediated by extrasynaptic NMDA receptors: a downward spiral. Cell Tissue Res 2014; 356:279-86. [PMID: 24496511 DOI: 10.1007/s00441-013-1789-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 12/19/2013] [Indexed: 12/27/2022]
Abstract
It is becoming increasingly clear that aberrant neuronal activity can be the cause and the result of amyloid beta production. Synaptic activation facilitates non-amyloidogenic processing of amyloid precursor protein (APP) and cell survival, primarily through synaptic NMDA receptors (NMDARs) and perhaps specifically those containing GluN2A-subunits. In contrast, extrasynaptic and GluN2B-containing NMDARs promote beta-secretase cleavage of APP into amyloid-beta (Aβ). The opposing nature of these NMDAR populations is reflected in their control over cell survival and death pathways. Subtle changes in glutamate homeostasis may shift the balance between these pathways and could play a role in Alzheimer's disease (AD). Indeed, Aβ production, regional loss of brain connectivity and neurodegeneration correlate with neuronal activity in AD patients. From another perspective, Aβ oligomers (Aβo) alter neuronal signaling through several mechanisms involving NMDARs and intracellular calcium mishandling. While Aβo affect multiple receptors, GluN2B-NMDARs have emerged as primary mediators of altered synaptic plasticity and neurotoxicity. Memantine and its successor, NitroMemantine, are efficient at blocking or reversing the deleterious actions of Aβo largely due to their selectivity for extrasynaptic NMDARs. Recently, Aβo were shown to trigger astrocytic release of glutamate to the extrasynaptic space where it activates NMDARs to promote further Aβ production and synaptic depression. Combined with the reciprocal regulation between neuronal activity and Aβ production, extrasynaptic glutamate release adds to a maladaptive model and ultimately results in synaptotoxicity and neurodegeneration of AD. Extrasynaptic NMDAR antagonists remain as a promising therapeutic avenue by interfering with this cascade.
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Affiliation(s)
- Travis Rush
- INSERM, U836, Equipe 12, BP 170, Grenoble, Cedex 9, 38042, France
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86
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Muñoz FJ, Godoy JA, Cerpa W, Poblete IM, Huidobro-Toro JP, Inestrosa NC. Wnt-5a increases NO and modulates NMDA receptor in rat hippocampal neurons. Biochem Biophys Res Commun 2014; 444:189-94. [PMID: 24440698 DOI: 10.1016/j.bbrc.2014.01.031] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 01/10/2014] [Indexed: 10/25/2022]
Abstract
Wnt signaling has a crucial role in synaptic function at the central nervous system. Here we evaluate whether Wnts affect nitric oxide (NO) generation in hippocampal neurons. We found that non-canonical Wnt-5a triggers NO production; however, Wnt-3a a canonical ligand did not exert the same effect. Co-administration of Wnt-5a with the soluble Frizzled related protein-2 (sFRP-2) a Wnt antagonist blocked the NO production. Wnt-5a activates the non-canonical Wnt/Ca(2+) signaling through a mechanism that depends on Ca(2+) release from Ryanodine-sensitive internal stores. The increase in NO levels evoked by Wnt-5a promotes the insertion of the GluN2B subunit of the NMDA receptor (NMDAR) into the neuronal cell surface. To the best of our knowledge, this is the first time that Wnt-5a signaling is related to NO production, which in turn increases NMDARs trafficking to the cell surface.
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Affiliation(s)
- Francisco J Muñoz
- Centro de Envejecimiento y Regeneración (CARE), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago de Chile, Chile; Laboratory of Molecular Physiology and Channelopathies, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Parc de Recerca Biomédica de Barcelona, Spain
| | - Juan A Godoy
- Centro de Envejecimiento y Regeneración (CARE), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago de Chile, Chile
| | - Waldo Cerpa
- Laboratorio de Función y Patología Neuronal, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago de Chile, Chile
| | - Inés M Poblete
- Centro de Envejecimiento y Regeneración (CARE), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago de Chile, Chile; Departamento de Fisiología, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago de Chile, Chile
| | - Juan Pablo Huidobro-Toro
- Centro de Envejecimiento y Regeneración (CARE), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago de Chile, Chile; Departamento de Fisiología, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago de Chile, Chile; Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago, Santiago de Chile, Chile
| | - Nibaldo C Inestrosa
- Centro de Envejecimiento y Regeneración (CARE), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago de Chile, Chile; Centre for Healthy Brain Ageing, School of Psychiatry, UNSW, Faculty of Medicine, University of New South Wales, Sydney, Australia.
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87
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The "memory kinases": roles of PKC isoforms in signal processing and memory formation. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 122:31-59. [PMID: 24484697 DOI: 10.1016/b978-0-12-420170-5.00002-7] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The protein kinase C (PKC) isoforms, which play an essential role in transmembrane signal conduction, can be viewed as a family of "memory kinases." Evidence is emerging that they are critically involved in memory acquisition and maintenance, in addition to their involvement in other functions of cells. Deficits in PKC signal cascades in neurons are one of the earliest abnormalities in the brains of patients suffering from Alzheimer's disease. Their dysfunction is also involved in several other types of memory impairments, including those related to emotion, mental retardation, brain injury, and vascular dementia/ischemic stroke. Inhibition of PKC activity leads to a reduced capacity of many types of learning and memory, but may have therapeutic values in treating substance abuse or aversive memories. PKC activators, on the other hand, have been shown to possess memory-enhancing and antidementia actions. PKC pharmacology may, therefore, represent an attractive area for developing effective cognitive drugs for the treatment of many types of memory disorders and dementias.
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88
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The prion protein ligand, stress-inducible phosphoprotein 1, regulates amyloid-β oligomer toxicity. J Neurosci 2013; 33:16552-64. [PMID: 24133259 DOI: 10.1523/jneurosci.3214-13.2013] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
In Alzheimer's disease (AD), soluble amyloid-β oligomers (AβOs) trigger neurotoxic signaling, at least partially, via the cellular prion protein (PrP(C)). However, it is unknown whether other ligands of PrP(C) can regulate this potentially toxic interaction. Stress-inducible phosphoprotein 1 (STI1), an Hsp90 cochaperone secreted by astrocytes, binds to PrP(C) in the vicinity of the AβO binding site to protect neurons against toxic stimuli. Here, we investigated a potential role of STI1 in AβO toxicity. We confirmed the specific binding of AβOs and STI1 to the PrP and showed that STI1 efficiently inhibited AβO binding to PrP in vitro (IC50 of ∼70 nm) and also decreased AβO binding to cultured mouse primary hippocampal neurons. Treatment with STI1 prevented AβO-induced synaptic loss and neuronal death in mouse cultured neurons and long-term potentiation inhibition in mouse hippocampal slices. Interestingly, STI1-haploinsufficient neurons were more sensitive to AβO-induced cell death and could be rescued by treatment with recombinant STI1. Noteworthy, both AβO binding to PrP(C) and PrP(C)-dependent AβO toxicity were inhibited by TPR2A, the PrP(C)-interacting domain of STI1. Additionally, PrP(C)-STI1 engagement activated α7 nicotinic acetylcholine receptors, which participated in neuroprotection against AβO-induced toxicity. We found an age-dependent upregulation of cortical STI1 in the APPswe/PS1dE9 mouse model of AD and in the brains of AD-affected individuals, suggesting a compensatory response. Our findings reveal a previously unrecognized role of the PrP(C) ligand STI1 in protecting neurons in AD and suggest a novel pathway that may help to offset AβO-induced toxicity.
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89
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Lourenco MV, Clarke JR, Frozza RL, Bomfim TR, Forny-Germano L, Batista AF, Sathler LB, Brito-Moreira J, Amaral OB, Silva CA, Freitas-Correa L, Espírito-Santo S, Campello-Costa P, Houzel JC, Klein WL, Holscher C, Carvalheira JB, Silva AM, Velloso LA, Munoz DP, Ferreira ST, De Felice FG. TNF-α mediates PKR-dependent memory impairment and brain IRS-1 inhibition induced by Alzheimer's β-amyloid oligomers in mice and monkeys. Cell Metab 2013; 18:831-43. [PMID: 24315369 DOI: 10.1016/j.cmet.2013.11.002] [Citation(s) in RCA: 293] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 09/17/2013] [Accepted: 10/18/2013] [Indexed: 02/07/2023]
Abstract
Alzheimer's disease (AD) and type 2 diabetes appear to share similar pathogenic mechanisms. dsRNA-dependent protein kinase (PKR) underlies peripheral insulin resistance in metabolic disorders. PKR phosphorylates eukaryotic translation initiation factor 2α (eIF2α-P), and AD brains exhibit elevated phospho-PKR and eIF2α-P levels. Whether and how PKR and eIF2α-P participate in defective brain insulin signaling and cognitive impairment in AD are unknown. We report that β-amyloid oligomers, AD-associated toxins, activate PKR in a tumor necrosis factor α (TNF-α)-dependent manner, resulting in eIF2α-P, neuronal insulin receptor substrate (IRS-1) inhibition, synapse loss, and memory impairment. Brain phospho-PKR and eIF2α-P were elevated in AD animal models, including monkeys given intracerebroventricular oligomer infusions. Oligomers failed to trigger eIF2α-P and cognitive impairment in PKR(-/-) and TNFR1(-/-) mice. Bolstering insulin signaling rescued phospho-PKR and eIF2α-P. Results reveal pathogenic mechanisms shared by AD and diabetes and establish that proinflammatory signaling mediates oligomer-induced IRS-1 inhibition and PKR-dependent synapse and memory loss.
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Affiliation(s)
- Mychael V Lourenco
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
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90
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Memantine rescues transient cognitive impairment caused by high-molecular-weight aβ oligomers but not the persistent impairment induced by low-molecular-weight oligomers. J Neurosci 2013; 33:9626-34. [PMID: 23739959 DOI: 10.1523/jneurosci.0482-13.2013] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Brain accumulation of soluble amyloid-β oligomers (AβOs) has been implicated in synapse failure and cognitive impairment in Alzheimer's disease (AD). However, whether and how oligomers of different sizes induce synapse dysfunction is a matter of controversy. Here, we report that low-molecular-weight (LMW) and high-molecular-weight (HMW) Aβ oligomers differentially impact synapses and memory. A single intracerebroventricular injection of LMW AβOs (10 pmol) induced rapid and persistent cognitive impairment in mice. On the other hand, memory deficit induced by HMW AβOs (10 pmol) was found to be reversible. While memory impairment in LMW oligomer-injected mice was associated with decreased hippocampal synaptophysin and GluN2B immunoreactivities, synaptic pathology was not detected in the hippocampi of HMW oligomer-injected mice. On the other hand, HMW oligomers, but not LMW oligomers, induced oxidative stress in hippocampal neurons. Memantine rescued both neuronal oxidative stress and the transient memory impairment caused by HMW oligomers, but did not prevent the persistent cognitive deficit induced by LMW oligomers. Results establish that different Aβ oligomer assemblies act in an orchestrated manner, inducing different pathologies and leading to synapse dysfunction. Furthermore, results suggest a mechanistic explanation for the limited efficacy of memantine in preventing memory loss in AD.
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91
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Paula-Lima AC, Hidalgo C. Amyloid β-peptide oligomers, ryanodine receptor-mediated Ca(2+) release, and Wnt-5a/Ca(2+) signaling: opposing roles in neuronal mitochondrial dynamics? Front Cell Neurosci 2013; 7:120. [PMID: 23908603 PMCID: PMC3727079 DOI: 10.3389/fncel.2013.00120] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 07/10/2013] [Indexed: 01/08/2023] Open
Affiliation(s)
- Andrea C Paula-Lima
- Faculty of Dentistry, Department of Basic and Communitarian Sciences, Universidad de Chile Santiago, Chile ; Centro de Estudios Moleculares de la Célula, Universidad de Chile Santiago, Chile ; Biomedical Neuroscience Institute, Universidad de Chile Santiago, Chile
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92
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Silva-Alvarez C, Arrázola MS, Godoy JA, Ordenes D, Inestrosa NC. Canonical Wnt signaling protects hippocampal neurons from Aβ oligomers: role of non-canonical Wnt-5a/Ca(2+) in mitochondrial dynamics. Front Cell Neurosci 2013; 7:97. [PMID: 23805073 PMCID: PMC3691552 DOI: 10.3389/fncel.2013.00097] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 06/03/2013] [Indexed: 12/26/2022] Open
Abstract
Alzheimer's disease (AD) is the most common type of age-related dementia. The disease is characterized by a progressive loss of cognitive abilities, severe neurodegeneration, synaptic loss and mitochondrial dysfunction. The Wnt signaling pathway participates in the development of the central nervous system and growing evidence indicates that Wnts also regulate the function of the adult nervous system. We report here, that indirect activation of canonical Wnt/β-catenin signaling using Bromoindirubin-30-Oxime (6-BIO), an inhibitor of glycogen synthase kinase-3β, protects hippocampal neurons from amyloid-β (Aβ) oligomers with the concomitant blockade of neuronal apoptosis. More importantly, activation with Wnt-5a, a non-canonical Wnt ligand, results in the modulation of mitochondrial dynamics, preventing the changes induced by Aβ oligomers (Aβo) in mitochondrial fission-fusion dynamics and modulates Bcl-2 increases induced by oligomers. The canonical Wnt-3a ligand neither the secreted Frizzled-Related Protein (sFRP), a Wnt scavenger, did not prevent these effects. In contrast, some of the Aβ oligomer effects were blocked by Ryanodine. We conclude that canonical Wnt/β-catenin signaling controls neuronal survival, and that non-canonical Wnt/Ca(2+)signaling modulates mitochondrial dysfunction. Since mitochondrial dysfunction is present in neurodegenerative diseases, the therapeutic possibilities of the activation of Wnt signaling are evident.
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Affiliation(s)
- Carmen Silva-Alvarez
- Departamento de Biología Celular y Molecular, Centro de Envejecimiento y Regeneración, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile Santiago, Chile
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93
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Ramser EM, Gan KJ, Decker H, Fan EY, Suzuki MM, Ferreira ST, Silverman MA. Amyloid-β oligomers induce tau-independent disruption of BDNF axonal transport via calcineurin activation in cultured hippocampal neurons. Mol Biol Cell 2013; 24:2494-505. [PMID: 23783030 PMCID: PMC3744947 DOI: 10.1091/mbc.e12-12-0858] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The role of tau in axonal transport disruption during early-stage Alzheimer disease is controversial. The amyloid-β oligomers markedly impair BDNF transport in primary wild-type and tau-knockout neurons. This occurs by nonexcitotoxic activation of calcineurin, and inhibition of calcineurin rescues transport defects independent of tau. Disruption of fast axonal transport (FAT) is an early pathological event in Alzheimer's disease (AD). Soluble amyloid-β oligomers (AβOs), increasingly recognized as proximal neurotoxins in AD, impair organelle transport in cultured neurons and transgenic mouse models. AβOs also stimulate hyperphosphorylation of the axonal microtubule-associated protein, tau. However, the role of tau in FAT disruption is controversial. Here we show that AβOs reduce vesicular transport of brain-derived neurotrophic factor (BDNF) in hippocampal neurons from both wild-type and tau-knockout mice, indicating that tau is not required for transport disruption. FAT inhibition is not accompanied by microtubule destabilization or neuronal death. Significantly, inhibition of calcineurin (CaN), a calcium-dependent phosphatase implicated in AD pathogenesis, rescues BDNF transport. Moreover, inhibition of protein phosphatase 1 and glycogen synthase kinase 3β, downstream targets of CaN, prevents BDNF transport defects induced by AβOs. We further show that AβOs induce CaN activation through nonexcitotoxic calcium signaling. Results implicate CaN in FAT regulation and demonstrate that tau is not required for AβO-induced BDNF transport disruption.
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Affiliation(s)
- Elisa M Ramser
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
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94
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Walker MP, LaFerla FM, Oddo SS, Brewer GJ. Reversible epigenetic histone modifications and Bdnf expression in neurons with aging and from a mouse model of Alzheimer's disease. AGE (DORDRECHT, NETHERLANDS) 2013; 35:519-31. [PMID: 22237558 PMCID: PMC3636384 DOI: 10.1007/s11357-011-9375-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Accepted: 12/18/2011] [Indexed: 05/02/2023]
Abstract
With aging and Alzheimer's disease (AD), there is an increased sensitivity to stress along with declines in the memory-associated neurotrophin brain-derived neurotrophic factor in AD. We have replicated this aging phenotype in cultured neurons from aged mice despite being grown in the same environmental conditions as young neurons. This led us to hypothesize that age-related differences in epigenetic acetylation and methylation of histones are associated with age-related gene regulation. We cultured hippocampal/cortical neurons from the 3xTg-AD mouse model and from non-transgenic mice to quantify single cell acetylation and methylation levels across the life span. In non-transgenic neurons, H3 acetylation was unchanged with age, while H4 acetylation decreased with age of the donor. Compared to non-transgenic neurons, 3xTg-AD neurons had higher levels of H3 and H4 acetylation beginning at 4 months of age. In contrast to non-transgenic neurons, 3xTg-AD neurons increased acetylation with age; 3xTg-AD neurons also responded differently to inhibition of histone deacetylases at an early age. Importantly, treatment of non-transgenic neurons with the AD peptide Aβ also elevated levels of acetylation. We also examined the repressive function of histone H3 lysine 9 (H3K9) methylation. H3K9 methylation increased with age in non-transgenic neurons, which was amplified further in 3xTg-AD neurons. The dominant effect of higher H3K9 methylation was supported by lower Bdnf gene expression in non-transgenic and 3xTg-AD mice. These data show that the epigenetic states of non-transgenic and 3xTg-AD brain neurons are profoundly different and reversible, beginning at 4 months of age when the first memory deficits are reported.
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Affiliation(s)
- Michael P. Walker
- />Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL 62794-9626 USA
| | - Frank M. LaFerla
- />Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA 92697 USA
| | - Salvador S. Oddo
- />Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA 92697 USA
| | - Gregory J. Brewer
- />Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL 62794-9626 USA
- />Department of Neurology, Southern Illinois University School of Medicine, Springfield, IL 62794-9626 USA
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95
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Paula-Lima AC, Brito-Moreira J, Ferreira ST. Deregulation of excitatory neurotransmission underlying synapse failure in Alzheimer's disease. J Neurochem 2013; 126:191-202. [PMID: 23668663 DOI: 10.1111/jnc.12304] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 05/09/2013] [Accepted: 05/10/2013] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia in the elderly. Memory loss in AD is increasingly attributed to soluble oligomers of the amyloid-β peptide (AβOs), toxins that accumulate in AD brains and target particular synapses. Glutamate receptors appear to be centrally involved in synaptic targeting by AβOs. Once bound to neurons, AβOs dysregulate the activity and reduce the surface expression of both N-methyl-D-aspartate (NMDA) and 2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl)propanoic acid (AMPA) types of glutamate receptors, impairing signaling pathways involved in synaptic plasticity. In the extracellular milieu, AβOs promote accumulation of the excitatory amino acids, glutamate and D-serine. This leads to overactivation of glutamate receptors, triggering abnormal calcium signals with noxious impacts on neurons. Here, we review key findings linking AβOs to deregulated glutamate neurotransmission and implicating this as a primary mechanism of synapse failure in AD. We also discuss strategies to counteract the impact of AβOs on excitatory neurotransmission. In particular, we review evidence showing that inducing neuronal hyperpolarization via activation of inhibitory GABA(A) receptors prevents AβO-induced excitotoxicity, suggesting that this could comprise a possible therapeutic approach in AD.
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Affiliation(s)
- Andrea C Paula-Lima
- Department of Basic Sciences, Faculty of Dentistry, University of Chile, Santiago, Chile.
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96
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Zolezzi JM, Silva-Alvarez C, Ordenes D, Godoy JA, Carvajal FJ, Santos MJ, Inestrosa NC. Peroxisome proliferator-activated receptor (PPAR) γ and PPARα agonists modulate mitochondrial fusion-fission dynamics: relevance to reactive oxygen species (ROS)-related neurodegenerative disorders? PLoS One 2013; 8:e64019. [PMID: 23675519 PMCID: PMC3652852 DOI: 10.1371/journal.pone.0064019] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 04/09/2013] [Indexed: 12/23/2022] Open
Abstract
Recent studies showed that the activation of the retinoid X receptor, which dimerizes with peroxisome proliferator-activated receptors (PPARs), leads to an enhanced clearance of Aβ from the brain of transgenic mice model of Alzheimer's disease (AD), because an increased expression of apolipoprotein E and it main transporters. However, the effects observed must involve additional underlying mechanisms that have not been yet explored. Several studies conducted in our laboratory suggest that part of the effects observed for the PPARs agonist might involves mitochondrial function and, particularly, mitochondrial dynamics. In the present study we assessed the effects of oxidative stress challenge on mitochondrial morphology and mitochondrial dynamics-related proteins in hippocampal neurons. Using immunofluorescence, we evaluated the PPARγ co-activator 1α (PGC-1α), dynamin related protein 1 (DRP1), mitochondrial fission protein 1 (FIS1), and mitochondrial length, in order to determine if PPARs agonist pre-treatment is able to protect mitochondrial population from hippocampal neurons through modulation of the mitochondrial fusion-fission events. Our results suggest that both a PPARγ agonist (ciglitazone) and a PPARα agonist (WY 14.643) are able to protect neurons by modulating mitochondrial fusion and fission, leading to a better response of neurons to oxidative stress, suggesting that a PPAR based therapy could acts simultaneously in different cellular components. Additionally, our results suggest that PGC-1α and mitochondrial dynamics should be further studied in future therapy research oriented to ameliorate neurodegenerative disorders, such as AD.
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Affiliation(s)
- Juan M. Zolezzi
- Departamento de Biología, Facultad de Ciencias, Universidad de Tarapacá, Arica, Chile
| | - Carmen Silva-Alvarez
- Centro de Envejecimiento y Regeneración (CARE), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Daniela Ordenes
- Centro de Envejecimiento y Regeneración (CARE), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan A. Godoy
- Centro de Envejecimiento y Regeneración (CARE), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Francisco J. Carvajal
- Centro de Envejecimiento y Regeneración (CARE), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Manuel J. Santos
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nibaldo C. Inestrosa
- Centro de Envejecimiento y Regeneración (CARE), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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97
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Cornejo VH, Hetz C. The unfolded protein response in Alzheimer’s disease. Semin Immunopathol 2013; 35:277-92. [DOI: 10.1007/s00281-013-0373-9] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 03/13/2013] [Indexed: 01/05/2023]
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98
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De Felice FG. Alzheimer's disease and insulin resistance: translating basic science into clinical applications. J Clin Invest 2013; 123:531-9. [PMID: 23485579 DOI: 10.1172/jci64595] [Citation(s) in RCA: 246] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Alzheimer's disease (AD) and diabetes are currently considered among the top threats to human health worldwide. Intriguingly, a connection between these diseases has been established during the past decade, since insulin resistance, a hallmark of type 2 diabetes, also develops in Alzheimer brains. In this article, the molecular and cellular mechanisms underlying defective brain insulin signaling in AD are discussed, with emphasis on evidence that Alzheimer's and diabetes share common inflammatory signaling pathways. I put forward here a hypothesis on how a cross-talk between peripheral tissues and the brain might influence the development of AD, and highlight important unanswered questions in the field. Furthermore, I discuss a rational basis for the use of antidiabetic agents as novel and potentially effective therapeutics in AD.
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Affiliation(s)
- Fernanda G De Felice
- Institute of Medical Biochemistry, CCS, Room H2-019, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21944-590, Brazil.
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99
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Hsiao CW, Peng TI, Peng AC, Reiter RJ, Tanaka M, Lai YK, Jou MJ. Long-term Aβ exposure augments mCa2+-independent mROS-mediated depletion of cardiolipin for the shift of a lethal transient mitochondrial permeability transition to its permanent mode in NARP cybrids: a protective targeting of melatonin. J Pineal Res 2013; 54:107-25. [PMID: 24446866 DOI: 10.1111/jpi.12004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 07/27/2012] [Indexed: 11/27/2022]
Abstract
Mitochondrial dysfunction is a hallmark of amyloid β-peptide (Aβ)-induced neurodegeneration of Alzheimer's disease (AD). This study investigated whether mtDNA T8993G mutation-induced complex V inhibition, clinically associated with neurological muscle weakness, ataxia, and retinitis pigmentosa (NARP), is a potential risk factor for AD and the pathological link for long-term exposure of Aβ-induced mitochondrial toxicity and apoptosis in NARP cybrids. Using noninvasive fluorescence probe-coupled laser scanning imaging microscopy and NARP cybrids harboring 98% mutant genes along with its parental 143B osteosarcoma cells, we demonstrated that Aβ-augmented mitochondrial Ca(2+) (mCa(2+))-independent mitochondrial reactive oxygen species (mROS) formation for a cardiolipin (CL, a major mitochondrial protective phospholipid)-dependent lethal modulation of the mitochondrial permeability transition (MPT). Aβ augmented not only the amount but also the propagation rate of mROS-induced mROS formation to significantly depolarize mitochondrial membrane potential (∆Ψ(m)) and reduce mCa(2+) stress. Aβ-augmented mROS oxidized and depleted CL, thereby enhances mitochondrial fission and movement retardation, which promoted the NARP-augmented lethal transient-MPT (t-MPT) to switch to its irreversible mode of permanent-MPT (p-MPT). Interestingly, melatonin, a multiple mitochondrial protector, markedly reduced Aβ-augmented mROS formation and therefore significantly reduced mROS-mediated depolarization of ∆Ψ(m), fission of mitochondria and retardation of mitochondrial movement to stabilize CL and hence the MPT. In the presence of melatonin, Aβ-promoted p-MPT was reversed to a protective t-MPT, which preserved ∆Ψ(m) and lowered elevated mCa(2+) to sublethal levels for an enhanced mCa(2+)-dependent O(2) consumption. Thus, melatonin may potentially rescue AD patients associated with NARP symptoms.
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Affiliation(s)
- Chia-Wei Hsiao
- Department of Life Science and Institute of Biotechnology, National Tsing Hua University, Hsinchu, Taiwan
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100
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SanMartín CD, Paula-Lima AC, Hidalgo C, Núñez MT. Sub-lethal levels of amyloid β-peptide oligomers decrease non-transferrin-bound iron uptake and do not potentiate iron toxicity in primary hippocampal neurons. Biometals 2012; 25:805-13. [DOI: 10.1007/s10534-012-9545-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Accepted: 03/26/2012] [Indexed: 10/28/2022]
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