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Hassan M, Yasir M, Shahzadi S, Chun W, Kloczkowski A. Molecular Role of Protein Phosphatases in Alzheimer's and Other Neurodegenerative Diseases. Biomedicines 2024; 12:1097. [PMID: 38791058 PMCID: PMC11117500 DOI: 10.3390/biomedicines12051097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 05/02/2024] [Accepted: 05/14/2024] [Indexed: 05/26/2024] Open
Abstract
Alzheimer's disease (AD) is distinguished by the gradual loss of cognitive function, which is associated with neuronal loss and death. Accumulating evidence supports that protein phosphatases (PPs; PP1, PP2A, PP2B, PP4, PP5, PP6, and PP7) are directly linked with amyloid beta (Aβ) as well as the formation of the neurofibrillary tangles (NFTs) causing AD. Published data reported lower PP1 and PP2A activity in both gray and white matters in AD brains than in the controls, which clearly shows that dysfunctional phosphatases play a significant role in AD. Moreover, PP2A is also a major causing factor of AD through the deregulation of the tau protein. Here, we review recent advances on the role of protein phosphatases in the pathology of AD and other neurodegenerative diseases. A better understanding of this problem may lead to the development of phosphatase-targeted therapies for neurodegenerative disorders in the near future.
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Affiliation(s)
- Mubashir Hassan
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children’s Hospital, Columbus, OH 43205, USA;
| | - Muhammad Yasir
- Department of Pharmacology, Kangwon National University School of Medicine, Chuncheon 24341, Republic of Korea; (M.Y.); (W.C.)
| | - Saba Shahzadi
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children’s Hospital, Columbus, OH 43205, USA;
| | - Wanjoo Chun
- Department of Pharmacology, Kangwon National University School of Medicine, Chuncheon 24341, Republic of Korea; (M.Y.); (W.C.)
| | - Andrzej Kloczkowski
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children’s Hospital, Columbus, OH 43205, USA;
- Department of Pediatrics, The Ohio State University, Columbus, OH 43205, USA
- Department of Biomedical Informatics, The Ohio State University, Columbus, OH 43210, USA
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Yadav Y, Sharma M, Dey CS. PP1γ regulates neuronal insulin signaling and aggravates insulin resistance leading to AD-like phenotypes. Cell Commun Signal 2023; 21:82. [PMID: 37085815 PMCID: PMC10120118 DOI: 10.1186/s12964-023-01071-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 02/08/2023] [Indexed: 04/23/2023] Open
Abstract
BACKGROUND PP1γ is one of the isoforms of catalytic subunit of a Ser/Thr phosphatase PP1. The role of PP1γ in cellular regulation is largely unknown. The present study investigated the role of PP1γ in regulating neuronal insulin signaling and insulin resistance in neuronal cells. PP1 was inhibited in mouse neuroblastoma cells (N2a) and human neuroblastoma cells (SH-SY5Y). The expression of PP1α and PP1γ was determined in insulin resistant N2a, SH-SY5Y cells and in high-fat-diet-fed-diabetic mice whole-brain-lysates. PP1α and PP1γ were silenced by siRNA in N2a and SH-SY5Y cells and effect was tested on AKT isoforms, AS160 and GSK3 isoforms using western immunoblot, GLUT4 translocation by confocal microscopy and glucose uptake by fluorescence-based assay. RESULTS Results showed that, in one hand PP1γ, and not PP1α, regulates neuronal insulin signaling and insulin resistance by regulating phosphorylation of AKT2 via AKT2-AS160-GLUT4 axis. On the other hand, PP1γ regulates phosphorylation of GSK3β via AKT2 while phosphorylation of GSK3α via MLK3. Imbalance in this regulation results into AD-like phenotype. CONCLUSION PP1γ acts as a linker, regulating two pathophysiological conditions, neuronal insulin resistance and AD. Video Abstract.
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Affiliation(s)
- Yamini Yadav
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India
| | - Medha Sharma
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India
| | - Chinmoy Sankar Dey
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India.
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3
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Kate Gadanec L, Qaradakhi T, Renee McSweeney K, Matsoukas JM, Apostolopoulos V, Burrell LM, Zulli A. Diminazene aceturate uses different pathways to induce relaxation in healthy and atherogenic blood vessels. Biochem Pharmacol 2023; 208:115397. [PMID: 36566945 DOI: 10.1016/j.bcp.2022.115397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 12/17/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
Diminazene aceturate (DIZE), a putative angiotensin-converting enzyme 2 (ACE2) activator, elicits relaxation in various animal models. This study aimed to determine the relaxing mechanisms in internal iliac arteries utilised by DIZE in healthy and atherogenic rabbit models. Studies were conducted on internal iliac artery rings retrieved from male New Zealand White rabbits fed a 4-week healthy control (n = 24) or atherogenic diet (n = 20). To investigate pathways utilised by DIZE to promote arterial relaxation, a DIZE dose response [10-9.0 M - 10-5.0 M] was performed on pre-contracted rings incubated with pharmaceuticals that target: components of the renin-angiotensin system; endothelial- and vascular smooth muscle-dependent mechanisms; protein kinases; and potassium channels. ACE2 expression was quantified by immunohistochemistry analysis following a 2 hr or 4 hr DIZE incubation. DIZE significantly enhanced vessel relaxation in atherogenic rings at doses [10-5.5 M] (p < 0.01) and [10-5.0 M] (p < 0.0001), when compared to healthy controls. Comprehensive results from functional isometric studies determined that DIZE causes relaxation via different mechanisms depending on pathology. For the first time, we report that in healthy blood vessels DIZE exerts its direct relaxing effect through ACE2/AT2R and NO/sGC pathways; however, in atherogenesis this switches to MasR, arachidonic acid pathway (i.e., COX1/2, EET and DHET), MCLP, Ca2+ activated voltage channels, AMPK and ERK1/2. Moreover, quantitative immunohistochemical analysis demonstrated that DIZE increases artery ACE2 expression in a time dependent manner. We provide a detailed investigation of DIZE's mechanisms and demonstrate for the first time that in healthy and atherogenic arteries DIZE provides beneficial effects through directly inducing relaxation, albeit via different pathways.
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Affiliation(s)
- Laura Kate Gadanec
- Institute for Health and Sport, Victoria University, Melbourne 3030, Victoria, Australia.
| | - Tawar Qaradakhi
- Institute for Health and Sport, Victoria University, Melbourne 3030, Victoria, Australia.
| | | | - John M Matsoukas
- Institute for Health and Sport, Victoria University, Melbourne 3030, Victoria, Australia; Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Alberta T2N 4N1, Canada; NewDrug PC, Patras Science Park, 26500 Patras, Greece.
| | - Vasso Apostolopoulos
- Institute for Health and Sport, Victoria University, Melbourne 3030, Victoria, Australia; Australian Institute for Musculoskeletal Science, Melbourne 3021, Victoria, Australia.
| | - Louise M Burrell
- Department of Medicine, Austin Health, University of Melbourne, Heidelberg 3084, Victoria, Australia.
| | - Anthony Zulli
- Institute for Health and Sport, Victoria University, Melbourne 3030, Victoria, Australia.
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Shen Q, Wu X, Zhang Z, Zhang D, Yang S, Xing D. Gamma frequency light flicker regulates amyloid precursor protein trafficking for reducing β-amyloid load in Alzheimer's disease model. Aging Cell 2022; 21:e13573. [PMID: 35199454 PMCID: PMC8920449 DOI: 10.1111/acel.13573] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 01/05/2022] [Accepted: 02/02/2022] [Indexed: 11/28/2022] Open
Abstract
Inducing gamma oscillations with non‐invasive light flicker has been reported to impact Alzheimer's disease‐related pathology. However, it is unclear which signaling pathways are involved in reducing amyloid load. Here, we found that gamma frequency light flicker increased anchoring of amyloid precursor protein (APP) to the plasma membrane for non‐amyloidogenic processing, and then physically interacted with KCC2, a neuron‐specific K+‐Cl− cotransporter, suggesting that it is essential to maintain surface GABAA receptor α1 levels and reduce β‐amyloid (Aβ) production. Stimulation with such light flicker limited KCC2 internalization and subsequent degradation via both tyrosine phosphorylation and ubiquitination, leading to an increase in surface‐KCC2 levels. Specifically, PKC‐dependent phosphorylation of APP on a serine residue was induced by gamma frequency light flicker, which was responsible for maintaining plasma membrane levels of full‐length APP, leading to its reduced trafficking to endosomes and inhibiting the β‐secretase cleavage pathway. The activated PKC from the gamma frequency light flicker subsequently phosphorylated serine of KCC2 and stabilized it onto the cell surface, which contributed to the upregulation of surface GABAA receptor α1 levels. Together, these data indicate that enhancement of APP trafficking to the plasma membrane via light flicker plays a critical modulatory role in reduction of Aβ load in Alzheimer's disease.
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Affiliation(s)
- Qi Shen
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science South China Normal University Guangzhou China
- College of Biophotonics South China Normal University Guangzhou China
| | - Xiaolei Wu
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science South China Normal University Guangzhou China
- College of Biophotonics South China Normal University Guangzhou China
| | - Zhan Zhang
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science South China Normal University Guangzhou China
- College of Biophotonics South China Normal University Guangzhou China
| | - Di Zhang
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science South China Normal University Guangzhou China
- College of Biophotonics South China Normal University Guangzhou China
| | - Sihua Yang
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science South China Normal University Guangzhou China
- College of Biophotonics South China Normal University Guangzhou China
| | - Da Xing
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science South China Normal University Guangzhou China
- College of Biophotonics South China Normal University Guangzhou China
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Sun Q, Chen X, Liu W, Li S, Zhou Y, Yang X, Liu J. Effects of long-term low dose saxitoxin exposure on nerve damage in mice. Aging (Albany NY) 2021; 13:17211-17226. [PMID: 34197336 PMCID: PMC8312470 DOI: 10.18632/aging.203199] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 05/18/2021] [Indexed: 11/25/2022]
Abstract
Saxitoxin (STX), as a type of paralytic shellfish poisoning (PSP), is gaining widespread attention due to its long existence in edible shellfish. However, the mechanism underlying STX chronic exposure-induced effect is not well understood. Here, we evaluated the neurotoxicity effects of long-term low-dose STX exposure on C57/BL mice by behavioral tests, pathology analysis, and hippocampal proteomics analysis. Several behavioral tests showed that mice were in a cognitive deficiency after treated with 0, 0.5, 1.5, or 4.5 μg STX equivalents/kg body weight in the drinking water for 3 months. Compared with control mice, STX-exposed mice exhibited brain neuronal damage characterized by decreasing neuronal cells and thinner pyramidal cell layers in the hippocampal CA1 region. A total of 29 proteins were significantly altered in different STX dose groups. Bioinformatics analysis showed that protein phosphatase 1 (Ppp1c) and arylsulfatase A (Arsa) were involved in the hippo signaling pathway and sphingolipid metabolism pathway. The decreased expression of Arsa indicates that long-term low doses of STX exposure can cause neuronal inhibition, which is a process related to spatial memory impairment. Taken together, our study provides a new understanding of the molecular mechanisms of STX neurotoxicity.
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Affiliation(s)
- Qian Sun
- Key Laboratory of Modern Toxicology of Shenzhen, Shenzhen Medical Key Discipline of Health Toxicology (2020-2024), Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, Guangdong, People's Republic of China.,School of Public Health, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Xiao Chen
- Key Laboratory of Modern Toxicology of Shenzhen, Shenzhen Medical Key Discipline of Health Toxicology (2020-2024), Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, Guangdong, People's Republic of China
| | - Wei Liu
- Key Laboratory of Modern Toxicology of Shenzhen, Shenzhen Medical Key Discipline of Health Toxicology (2020-2024), Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, Guangdong, People's Republic of China
| | - Shenpan Li
- Key Laboratory of Modern Toxicology of Shenzhen, Shenzhen Medical Key Discipline of Health Toxicology (2020-2024), Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, Guangdong, People's Republic of China.,School of Public Health, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Yan Zhou
- Key Laboratory of Modern Toxicology of Shenzhen, Shenzhen Medical Key Discipline of Health Toxicology (2020-2024), Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, Guangdong, People's Republic of China
| | - Xingfen Yang
- School of Public Health, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Jianjun Liu
- Key Laboratory of Modern Toxicology of Shenzhen, Shenzhen Medical Key Discipline of Health Toxicology (2020-2024), Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, Guangdong, People's Republic of China
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Platholi J, Hemmings HC. Modulation of dendritic spines by protein phosphatase-1. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2020; 90:117-144. [PMID: 33706930 DOI: 10.1016/bs.apha.2020.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Protein phosphatase-1 (PP-1), a highly conserved multifunctional serine/threonine phosphatase, is enriched in dendritic spines where it plays a major role in modulating excitatory synaptic activity. In addition to established functions in spine maturation and development, multi-subunit holoenzyme forms of PP-1 modulate higher-order cognitive functions such learning and memory. Mechanisms involved in regulating PP-1 activity and localization in spines include interactions with neurabin and spinophilin, structurally related synaptic scaffolding proteins associated with the actin cytoskeleton. Since PP-1 is a critical element in synaptic development, signaling, and plasticity, alterations in PP-1 signaling in dendritic spines are implicated in various neurological and psychiatric disorders. The effects of PP-1 depend on its isoform-specific association with regulatory proteins and activation of downstream signaling pathways. Here we review the role of PP-1 and its binding proteins neurabin and spinophilin in both developing and established dendritic spines, as well as some of the disorders that result from its dysregulation.
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Affiliation(s)
- Jimcy Platholi
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, United States; Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, United States
| | - Hugh C Hemmings
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, United States; Department of Pharmacology, Weill Cornell Medicine, New York, NY, United States.
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Oliveira JM, da Cruz e Silva CB, Müller T, Martins TS, Cova M, da Cruz e Silva OAB, Henriques AG. Toward Neuroproteomics in Biological Psychiatry: A Systems Approach Unravels Okadaic Acid-Induced Alterations in the Neuronal Phosphoproteome. ACTA ACUST UNITED AC 2017; 21:550-563. [DOI: 10.1089/omi.2017.0108] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Joana Machado Oliveira
- Neurosciences and Signalling Laboratory, Department of Medical Sciences and Institute of Biomedicine (iBiMED), University of Aveiro, Aveiro, Portugal
| | | | - Thorsten Müller
- Cell Signaling, Biochemistry II—Molecular Biochemistry, Ruhr-University Bochum, Bochum, Germany
| | - Tânia Soares Martins
- Neurosciences and Signalling Laboratory, Department of Medical Sciences and Institute of Biomedicine (iBiMED), University of Aveiro, Aveiro, Portugal
| | - Marta Cova
- Neurosciences and Signalling Laboratory, Department of Medical Sciences and Institute of Biomedicine (iBiMED), University of Aveiro, Aveiro, Portugal
| | - Odete A. B. da Cruz e Silva
- Neurosciences and Signalling Laboratory, Department of Medical Sciences and Institute of Biomedicine (iBiMED), University of Aveiro, Aveiro, Portugal
| | - Ana Gabriela Henriques
- Neurosciences and Signalling Laboratory, Department of Medical Sciences and Institute of Biomedicine (iBiMED), University of Aveiro, Aveiro, Portugal
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Oliveira J, Costa M, de Almeida MSC, da Cruz e Silva OA, Henriques AG. Protein Phosphorylation is a Key Mechanism in Alzheimer’s Disease. J Alzheimers Dis 2017; 58:953-978. [DOI: 10.3233/jad-170176] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Joana Oliveira
- Department of Medical Sciences, Neuroscience and Signalling Laboratory, iBiMED, University of Aveiro, Aveiro, Portugal
| | - Márcio Costa
- Department of Medical Sciences, Neuroscience and Signalling Laboratory, iBiMED, University of Aveiro, Aveiro, Portugal
| | | | - Odete A.B. da Cruz e Silva
- Department of Medical Sciences, Neuroscience and Signalling Laboratory, iBiMED, University of Aveiro, Aveiro, Portugal
| | - Ana Gabriela Henriques
- Department of Medical Sciences, Neuroscience and Signalling Laboratory, iBiMED, University of Aveiro, Aveiro, Portugal
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9
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The Beta-amyloid protein of Alzheimer's disease: communication breakdown by modifying the neuronal cytoskeleton. Int J Alzheimers Dis 2013; 2013:910502. [PMID: 24416616 PMCID: PMC3876695 DOI: 10.1155/2013/910502] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 11/07/2013] [Indexed: 01/28/2023] Open
Abstract
Alzheimer's disease (AD) is one of the most prevalent severe neurological disorders afflicting our aged population. Cognitive decline, a major symptom exhibited by AD patients, is associated with neuritic dystrophy, a degenerative growth state of neurites. The molecular mechanisms governing neuritic dystrophy remain unclear. Mounting evidence indicates that the AD-causative agent, β-amyloid protein (Aβ), induces neuritic dystrophy. Indeed, neuritic dystrophy is commonly found decorating Aβ-rich amyloid plaques (APs) in the AD brain. Furthermore, disruption and degeneration of the neuronal microtubule system in neurons forming dystrophic neurites may occur as a consequence of Aβ-mediated downstream signaling. This review defines potential molecular pathways, which may be modulated subsequent to Aβ-dependent interactions with the neuronal membrane as a consequence of increasing amyloid burden in the brain.
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10
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Martin L, Latypova X, Wilson CM, Magnaudeix A, Perrin ML, Terro F. Tau protein phosphatases in Alzheimer's disease: the leading role of PP2A. Ageing Res Rev 2013; 12:39-49. [PMID: 22771380 DOI: 10.1016/j.arr.2012.06.008] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 06/28/2012] [Indexed: 12/21/2022]
Abstract
Tau phosphorylation is regulated by a balance between tau kinase and phosphatase activities. Disruption of this equilibrium was suggested to be at the origin of abnormal tau phosphorylation and thereby that might contributes to tau aggregation. Thus, understanding the regulation modes of tau dephosphorylation is of high interest in determining the possible causes at the origin of the formation of tau aggregates and to elaborate protection strategies to cope with these lesions in AD. Among the possible and relatively specific interventions that reverse tau phosphorylation is the stimulation of certain tau phosphatases. Here, we reviewed tau protein phosphatases, their physiological roles and regulation, their involvement in tau phosphorylation and the relevance to AD. We also reviewed the most common compounds acting on each tau phosphatase including PP2A.
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Affiliation(s)
- Ludovic Martin
- Groupe de Neurobiologie Cellulaire, Homéostasie cellulaire et pathologies, Faculté de Médecine, Limoges, France.
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Esteves SLC, Korrodi-Gregório L, Cotrim CZ, van Kleeff PJM, Domingues SC, da Cruz e Silva OAB, Fardilha M, da Cruz e Silva EF. Protein phosphatase 1γ isoforms linked interactions in the brain. J Mol Neurosci 2012; 50:179-97. [PMID: 23080069 DOI: 10.1007/s12031-012-9902-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 10/03/2012] [Indexed: 01/03/2023]
Abstract
Posttranslational protein modifications, in particular reversible protein phosphorylation, are important regulatory mechanisms involved in cellular signaling transduction pathways. Thousands of human proteins are phosphorylatable and the tight regulation of phosphorylation states is crucial for cell maintenance and development. Protein phosphorylation occurs primarily on serine, threonine, and tyrosine residues, through the antagonistic actions of protein kinases and phosphatases. The catalytic subunit of protein phosphatase 1 (PP1), a major Ser/Thr-phosphatase, associates with a large variety of regulatory subunits that define substrate specificity and determine specific cellular pathway responses. PP1 has been shown to bind to different proteins in the brain in order to execute key and differential functions. This work reports the identification of proteins expressed in the human brain that interact with PP1γ1 and PP1γ2 isoforms by the yeast two-hybrid method. An extensive search of PP1-binding motifs was performed for the proteins identified, revealing already known PP1 regulators but also novel interactors. Moreover, our results were integrated with the data of PP1γ interacting proteins from several public web databases, permitting the development of physical maps of the novel interactions. The PP1γ interactome thus obtained allowed for the identification of novel PP1 interacting proteins, supporting novel functions of PP1γ isoforms in the human brain.
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Affiliation(s)
- Sara L C Esteves
- Signal Transduction Laboratory, Centre for Cell Biology, Biology Department, University of Aveiro, 3810-193 Aveiro, Portugal
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Esteves SLC, Domingues SC, da Cruz e Silva OAB, Fardilha M, da Cruz e Silva EF. Protein phosphatase 1α interacting proteins in the human brain. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2012; 16:3-17. [PMID: 22321011 DOI: 10.1089/omi.2011.0041] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Protein Phosphatase 1 (PP1) is a major serine/threonine-phosphatase whose activity is dependent on its binding to regulatory subunits known as PP1 interacting proteins (PIPs), responsible for targeting PP1 to a specific cellular location, specifying its substrate or regulating its action. Today, more than 200 PIPs have been described involving PP1 in panoply of cellular mechanisms. Moreover, several PIPs have been identified that are tissue and event specific. In addition, the diversity of PP1/PIP complexes can further be achieved by the existence of several PP1 isoforms that can bind preferentially to a certain PIP. Thus, PP1/PIP complexes are highly specific for a particular function in the cell, and as such, they are excellent pharmacological targets. Hence, an in-depth survey was taken to identify specific PP1α PIPs in human brain by a high-throughput Yeast Two-Hybrid approach. Sixty-six proteins were recognized to bind PP1α, 39 being novel PIPs. A large protein interaction databases search was also performed to integrate with the results of the PP1α Human Brain Yeast Two-Hybrid and a total of 246 interactions were retrieved.
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Affiliation(s)
- Sara L C Esteves
- Signal Transduction Laboratory, Centre for Cell Biology, Biology Department, University of Aveiro, Portugal
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Zhang G, Lin L, Yang H, Wang T, Li X, Li G, Wen S, Wang D. WITHDRAWN: Effects of traditional Chinese medicine Fuzhisan on PP1 expression in the hippocampus of SAMP8 mice. JOURNAL OF ETHNOPHARMACOLOGY 2011:S0378-8741(11)00634-9. [PMID: 21920427 DOI: 10.1016/j.jep.2011.08.061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 08/21/2011] [Accepted: 08/25/2011] [Indexed: 05/31/2023]
Abstract
This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.
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Affiliation(s)
- Guowei Zhang
- Department of Neurology, the First Affiliated Hospital, Harbin Medical University, Harbin 150001, China; Inner Mongolia University for the Nationalities, Tongliao 028000, China
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Miar A, Álvarez V, Corao AI, Alonso B, Díaz M, Menéndez M, Martínez C, Calatayud M, Morís G, Coto E. Lack of association between protocadherin 11-X/Y (PCDH11X and PCDH11Y) polymorphisms and late onset Alzheimer's disease. Brain Res 2011; 1383:252-6. [DOI: 10.1016/j.brainres.2011.01.054] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 01/13/2011] [Accepted: 01/14/2011] [Indexed: 12/17/2022]
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Lack of association between PCDH11X genetic variation and late-onset Alzheimer's disease in a Han Chinese population. Brain Res 2010; 1357:152-6. [DOI: 10.1016/j.brainres.2010.08.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2010] [Revised: 08/01/2010] [Accepted: 08/04/2010] [Indexed: 01/21/2023]
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17
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S655 phosphorylation enhances APP secretory traffic. Mol Cell Biochem 2009; 328:145-54. [DOI: 10.1007/s11010-009-0084-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Accepted: 03/11/2009] [Indexed: 10/20/2022]
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Vintém APB, Henriques AG, da Cruz e Silva OA, da Cruz e Silva EF. PP1 inhibition by Aβ peptide as a potential pathological mechanism in Alzheimer's disease. Neurotoxicol Teratol 2009; 31:85-8. [DOI: 10.1016/j.ntt.2008.11.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Revised: 11/05/2008] [Accepted: 11/05/2008] [Indexed: 10/21/2022]
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Ikin AF, Causevic M, Pedrini S, Benson LS, Buxbaum JD, Suzuki T, Lovestone S, Higashiyama S, Mustelin T, Burgoyne RD, Gandy S. Evidence against roles for phorbol binding protein Munc13-1, ADAM adaptor Eve-1, or vesicle trafficking phosphoproteins Munc18 or NSF as phospho-state-sensitive modulators of phorbol/PKC-activated Alzheimer APP ectodomain shedding. Mol Neurodegener 2007; 2:23. [PMID: 18067682 PMCID: PMC2211485 DOI: 10.1186/1750-1326-2-23] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Accepted: 12/09/2007] [Indexed: 11/18/2022] Open
Abstract
Background Shedding of the Alzheimer amyloid precursor protein (APP) ectodomain can be accelerated by phorbol esters, compounds that act via protein kinase C (PKC) or through unconventional phorbol-binding proteins such as Munc13-1. We have previously demonstrated that application of phorbol esters or purified PKC potentiates budding of APP-bearing secretory vesicles at the trans-Golgi network (TGN) and toward the plasma membrane where APP becomes a substrate for enzymes responsible for shedding, known collectively as α-secretase(s). However, molecular identification of the presumptive "phospho-state-sensitive modulators of ectodomain shedding" (PMES) responsible for regulated shedding has been challenging. Here, we examined the effects on APP ectodomain shedding of four phorbol-sensitive proteins involved in regulation of vesicular membrane trafficking of APP: Munc13-1, Munc18, NSF, and Eve-1. Results Overexpression of either phorbol-sensitive wildtype Munc13-1 or phorbol-insensitive Munc13-1 H567K resulted in increased basal APP ectodomain shedding. However, in contrast to the report of Roßner et al (2004), phorbol ester-dependent APP ectodomain shedding from cells overexpressing APP and Munc13-1 wildtype was indistinguishable from that observed following application of phorbol to cells overexpressing APP and Munc13-1 H567K mutant. This pattern of similar effects on basal and stimulated APP shedding was also observed for Munc18 and NSF. Eve-1, an ADAM adaptor protein reported to be essential for PKC-regulated shedding of pro-EGF, was found to play no obvious role in regulated shedding of sAPPα. Conclusion Our results indicate that, in the HEK293 system, Munc13-1, Munc18, NSF, and EVE-1 fail to meet essential criteria for identity as PMES for APP.
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Affiliation(s)
- Annat F Ikin
- Farber Institute for Neurosciences of Thomas Jefferson University, 900 Walnut Street, Philadelphia, 19107, PA, USA.
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20
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Rebelo S, Vieira SI, Esselmann H, Wiltfang J, da Cruz e Silva EF, da Cruz e Silva OAB. Tyrosine 687 Phosphorylated Alzheimer’s Amyloid Precursor Protein Is Retained Intracellularly and Exhibits a Decreased Turnover Rate. NEURODEGENER DIS 2007; 4:78-87. [PMID: 17596701 DOI: 10.1159/000101831] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Tyrosine 687 (Y687) of the Alzheimer's amyloid precursor protein (APP) was shown to be phosphorylated in the brains of Alzheimer's disease patients. This residue lies within a typical endocytosis consensus motif commonly found in molecules with receptor functions, strongly suggesting a potential role for APP in signal transduction. Consequently, the work here described addressed how phosphorylation of Y687 may be affecting APP in terms of its proteolytic cleavage and subcellular distribution. Our data show that the APP mutant mimicking constitutive dephosphorylation of Y687 had a faster turnover rate, both in terms of maturation and metabolism, when compared to Wt-APP-GFP and even more so when compared to the mutant mimicking constitutive phosphorylation. Thus, the mutant mimicking constitutively phosphorylated Y687 had a much higher t(1/2) and was significantly retained both in the ER and TGN. Additionally, this mutant was not incorporated into visible vesicular structures, with a concomitant dramatic decrease in Abeta production. Our findings point to the direct phosphorylation of APP on Y687 as an important regulatory mechanism in terms of determining the subcellular localization of APP and modulating its processing via different proteolytic pathways.
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Affiliation(s)
- Sandra Rebelo
- Laboratório de Neurociências, Centro de Biologia Celular, Universidade de Aveiro, Aveiro, Portugal
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21
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Mansuy IM, Shenolikar S. Protein serine/threonine phosphatases in neuronal plasticity and disorders of learning and memory. Trends Neurosci 2006; 29:679-86. [PMID: 17084465 DOI: 10.1016/j.tins.2006.10.004] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Revised: 07/28/2006] [Accepted: 10/19/2006] [Indexed: 01/12/2023]
Abstract
Phosphorylation and dephosphorylation of cellular proteins by protein kinases and phosphatases represent important mechanisms for controlling major biological events. In the nervous system, protein phosphatases are contained in highly dynamic complexes localized within specialized subcellular compartments and they ensure timely dephosphorylation of multiple neuronal phosphoproteins. This modulates the responsiveness of individual synapses to neural activity and controls synaptic plasticity. These enzymes in turn play a key role in many forms of learning and memory, and their dysfunction contributes to cognitive deficits associated with aging and dementias or neurodegenerative diseases. Here, we review key modes of regulation of neuronal protein serine/threonine phosphatases and their contribution to disorders of learning and memory.
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Affiliation(s)
- Isabelle M Mansuy
- Brain Research Institute, Medical Faculty of the University Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
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22
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Raha-Chowdhury R, Andrews SR, Gruen JR. CAT 53: a protein phosphatase 1 nuclear targeting subunit encoded in the MHC Class I region strongly expressed in regions of the brain involved in memory, learning, and Alzheimer's disease. ACTA ACUST UNITED AC 2005; 138:70-83. [PMID: 15894402 DOI: 10.1016/j.molbrainres.2005.04.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2004] [Revised: 04/04/2005] [Accepted: 04/04/2005] [Indexed: 10/25/2022]
Abstract
We identified CAT 53 by cDNA hybridization selection as an expressed sequence tag (EST), located in the vicinity of HLA-C and designated as CAT (for HLA-C associated transcript) 53. CAT 53 encodes a protein described by others and commonly known as phosphatase 1 nuclear targeting subunit (PNUTS). PNUTS is a potent inhibitor of nuclear serine/threonine protein phosphatase 1 (PP1). We present the genomic organization of CAT 53, localize specific sites of mRNA transcription in thin sections of mouse brain by in-situ hybridization, and perform a structural analysis of the peptide domains. We also characterize the protein expression pattern for PNUTS by Western blotting and immunohistochemistry with PNUTS antibody in Alzheimer's disease (AD) brains and age-matched control brains. In-situ hybridization and immunohistochemistry analysis of human and mouse brain show high CAT 53 expression in the olfactory cortex, piriform cortex, and hippocampus. Very high expression of CAT 53 was found mainly in the hippocampus, frontal, and entorhinal cortex of control brains and in the neurofibrillary tangles of AD brain. In the hippocampus, CAT 53 is expressed in CA1 and CA3 cell layers and in the dentate gyrus. The hippocampus is known to play a fundamental role in learning and episodic memories and has been implicated in a number of neurological and psychiatric disorders, including AD, epilepsy, and schizophrenia. Our findings suggest that PNUTS, encoded by CAT 53 on 6p21.3, may have a role in the progression of AD.
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Affiliation(s)
- Ruma Raha-Chowdhury
- Cambridge Centre for Brain Repair, Department of Clinical Neuroscience, University of Cambridge, Forvie Site, Robinson Way, Cambridge CB2 2PY, UK.
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23
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da Cruz E Silva OAB, Vieira SI, Rebelo S, da Cruz e Silva EF. A Model System to Study Intracellular Trafficking and Processing of the Alzheimer’s Amyloid Precursor Protein. NEURODEGENER DIS 2004; 1:196-204. [PMID: 16908990 DOI: 10.1159/000080986] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The occurrence of consensus phosphorylation sites in the intracellular domain of the Alzheimer's amyloid precursor protein (APP), coupled with observations of their in vivo phosphorylation, prompted several workers to investigate the effects that phosphorylation of such sites could have on APP metabolism and subsequent Abeta production. However, hitherto all attempts to dissect the role played by such phosphorylation events failed to reveal substantial effects. Having decided to revisit this problem, our new approach was based on the following vectors: (1) site-directed mutagenesis of the target amino acids to mimic a specific phosphorylation state, (2) expression of wild-type and mutant APP-GFP (green fluorescent protein) fusion proteins for ease of visualization, (3) controlled low level expression to avoid 'flooding' cellular pathways, and (4) the use of cycloheximide to inhibit de novo protein synthesis. Using this method we were able to detect specific differences in APP processing that were correlated with the mimicked phosphorylation state of several phosphorylation sites. New combined methodologies, like the one described here, allow for the detailed analysis of key control points in the cellular metabolism of specific proteins that are central to neurodegenerative diseases and may be under the control of specific posttranslational modifications, such as reversible phosphorylation.
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24
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Rebelo S, Henriques AG, da Cruz e Silva EF, da Cruz e Silva OAB. Effect of cell density on intracellular levels of the Alzheimer's amyloid precursor protein. J Neurosci Res 2004; 76:406-14. [PMID: 15079870 DOI: 10.1002/jnr.20091] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The precise function of APP (Alzheimer's amyloid precursor protein) remains to be fully elucidated, but various lines of evidence suggest that it may be involved in cell adhesion processes. Because APP is a transmembrane glycoprotein, variations in its expression level may have direct bearing on its putative role in cell adhesion. Our results revealed that although APP levels did not change markedly with increasing cell density (ICD), there was a small but reproducible increase in APP expression at subconfluent conditions. Higher expression APP levels led to corresponding increases in the amount of APP processed and secreted APP (sAPP) released into the cell media. Given that phorbol esters stimulate the non-amyloidogenic pathway at the expense of reducing production of Abeta (the peptide found deposited as neuritic plaques in the brains of patients with Alzheimer's disease), thus providing an interesting therapeutic focus, we tested the effect of the phorbol 12-myristate 13-acetate (PMA) on APP processing at ICD. PMA not only stimulated sAPP release at all densities tested, but also produced a corresponding decrease in the intracellular levels of APP. Further experimentation revealed that increased APP expression with ICD was dependent on factors present in conditioned medium. Interestingly, exposing cells to the Abeta peptide itself could mimic these results, thus providing evidence for a potential positive feedback mechanism between Abeta production and intracellular APP levels.
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Affiliation(s)
- Sandra Rebelo
- Centro de Biologia Celular, Universidade de Aveiro, Aveiro, Portugal
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25
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Defelice FG, Ferreira ST. Physiopathological modulators of amyloid aggregation and novel pharmacological approaches in Alzheimer's disease. AN ACAD BRAS CIENC 2002; 74:265-84. [PMID: 12098753 DOI: 10.1590/s0001-37652002000200006] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The biological mechanisms underlying the neuropathology of Alzheimer's disease (AD) are complex, as several factors likely contribute to the development of the disease. Therefore, it is not surprising that a number of different possible therapeutic approaches addressing distinct aspects of this disease are currently being investigated. Among these are ways to prevent amyloid aggregation and/or deposition, to prevent neuronal degeneration, and to increase brain neurotransmitter levels. Here, we discuss possible roles of endogenous modulators of Abeta aggregation in the physiopathology of AD and some of the strategies currently under consideration to interfere with brain levels of beta-amyloid, its aggregation and neurotoxicity.
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Affiliation(s)
- Fernanda G Defelice
- Department of Medical Biochemistry, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Brazil
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26
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Abstract
This review presents an analysis of the current state of gerontological and geriatric research in Portugal, and highlights the need for a national consensus and funding for age-related research projects. Such efforts must be multidisciplinary, since the process of aging encompasses biological, psychological, social, economic and cultural aspects. Demographic studies reveal a growing population of elderly in Portugal as a result of a healthier population in general. This increased life expectancy, however, is accompanied by a parallel increase in degenerative pathologies and care costs among the elderly. Preventive medicine is an important tool to reduce health care costs and avoid or abbreviate suffering from age-related syndromes, but such projects on a national basis neither exists, nor does gerontology or geriatrics receive funding to perform needed research. Consequently, research on aging depends on the initiative of individual investigators who, without funding or cohesive programs, can do little to improve the low scientific output in this area. The implementation of a national program, that can establish health care policy and priorities as well as fund the necessary research, will permit organized cooperation among the different scientific disciplines related to aging. This is a crucial step toward improving present knowledge, ensuring application of experimental and statistical results to the clinical care of the aging population, and attract young investigators to this field.
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Affiliation(s)
- C Resende Oliveira
- Department of Biochemistry and Centre for Neurosciences, Faculty of Medicine, University of Coimbra, Rua Larga, 3004 504 Coimbra, Portugal.
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27
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Norrholm SD, Ouimet CC. Chronic fluoxetine administration to juvenile rats prevents age-associated dendritic spine proliferation in hippocampus. Brain Res 2000; 883:205-15. [PMID: 11074049 DOI: 10.1016/s0006-8993(00)02909-7] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The density of dendritic spines, the postsynaptic sites of most excitatory synapses, increases during the first 2 postnatal months in rat hippocampus. Significant alterations in hippocampal levels of serotonin and norepinephrine impact synaptic development during this time period. In the present study, dendritic spine density was studied in the hippocampus (CA1) and dentate gyrus of juvenile rats acutely and chronically exposed to antidepressant drugs that act on serotonin and norepinephrine. One group of 21-day-old rats was given a single injection of a serotonin specific re-uptake inhibitor (fluoxetine or fluvoxamine), a norepinephrine-specific re-uptake inhibitor (desipramine), or saline and killed after 24 h. A second group of rats was injected daily, beginning on postnatal day (PN) 21, for 3 weeks. This group was further subdivided into rats that were killed 1 day or 21 days after the last injection. Golgi analysis showed that a single injection of fluvoxamine produced a significant increase in dendritic spine density in stratum radiatum of CA1 and in the dentate gyrus. Further, acute treatment with all three antidepressants increased the total length of secondary dendrites in CA1, with fluoxetine and desipramine increasing the number of secondary dendrites as well. In fluoxetine-treated animals killed on days 42 or 62 (1 or 21 days post-treatment, respectively), dendritic spine density remained at levels present in CA1 at 21 days. These results show that acute antidepressant treatment can impact dendritic length and spine density, and raise the possibility that chronic fluoxetine treatment arrests spine development into young adulthood.
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Affiliation(s)
- S D Norrholm
- Program in Neuroscience, Department of Psychology, Florida State University, 211 Biomedical Research Facility, Tallahassee, FL 32306-4340, USA
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28
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Matovcik LM, Rhee SS, Schaefer JF, da Cruz e Silva EF, Kinder BK. Inhibition of protein phosphatase 1 decreases PTH secretion from isolated dispersed parathyroid cells. Mol Cell Endocrinol 1999; 154:171-7. [PMID: 10509811 DOI: 10.1016/s0303-7207(98)00224-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
To investigate the regulation of parathyroid hormone secretion by phosphatases we examined the effect of okadaic acid, a selective inhibitor of protein phosphatases (PP)-1 and -2A, on isolated, dispersed parathyroid cells. Okadaic acid inhibited secretion from intact bovine, intact human and streptolysin-O permeabilized bovine cells. Approximately 10(-6) M okadaic acid resulted in a 50% decrease in parathyroid hormone (PTH) secretion from both intact and permeabilized cells, consistent with PP-1 being the target of inhibition. Upon subcellular fractionation, PP-1 overlapped but was not identical to either PTH, a marker of the secretory granule, or Na+/K+-ATPase, a plasma membrane marker. In summary, PP-1 activity is involved in Ca2+-dependent but not basal PTH secretion.
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Affiliation(s)
- L M Matovcik
- VA Connecticut Healthcare System, and the Department of Surgery, Yale University School of Medicine, New Haven 06520-8062, USA.
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29
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Geller LN, Potter H. Chromosome missegregation and trisomy 21 mosaicism in Alzheimer's disease. Neurobiol Dis 1999; 6:167-79. [PMID: 10408806 DOI: 10.1006/nbdi.1999.0236] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
A connection between Alzheimer's disease (AD) and Down syndrome (trisomy 21) is indicated by the fact that all Down syndrome individuals develop Alzheimer's disease neuropathology by the 4th decade of life. Previous studies have examined the frequency of aneuploidy and other chromosomal defects in cells from familial Alzheimer's disease (FAD) patients, with varying results. To investigate the possibility that a specific type of aneuploidy--trisomy 21 mosaicism--may contribute to Alzheimer's disease, we used quantitative fluorescence in situ hybridization to measure the number of trisomy 21 cells in primary fibroblast cultures from AD and unaffected subjects. The 27 AD cultures, including 15 that were derived from individuals carrying FAD mutations in presenilin 1 or 2, exhibited a significant approximately twofold increase in the number of trisomy 21 cells compared to 13 control cultures. A small double-hybridization experiment suggested that the aneuploidy in AD cells was not limited to chromosome 21 but extended at least to chromosome 18 as well. In a parallel study, the endogenous presenilin proteins in fibroblasts were localized to the centrosomes, the nuclear envelope, and its associated interphase kinetochores. Together these results indicate that the presenilin proteins may be involved in mitosis and that FAD mutations in the presenilin genes may predispose to chromosome missegregation (nondisjunction). The data reported here also suggest that trisomy 21 mosaicism may contribute to other forms of AD that are not caused by a presenilin mutation.
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Affiliation(s)
- L N Geller
- Fish & Richardson P.C., Boston, Massachusetts 02115, USA
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30
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Sheppeck JE, Gauss CM, Chamberlin AR. Inhibition of the Ser-Thr phosphatases PP1 and PP2A by naturally occurring toxins. Bioorg Med Chem 1997; 5:1739-50. [PMID: 9354230 DOI: 10.1016/s0968-0896(97)00146-6] [Citation(s) in RCA: 133] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The okadaic acid class of naturally occurring toxins is a structurally diverse group of molecules that inhibit the protein phosphatases PP1 and PP2A. Studies providing information about the mode of binding between the toxins and the phosphatases contribute to an overall understanding of the signal transduction pathways in which the phosphatases are involved.
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Affiliation(s)
- J E Sheppeck
- Department of Chemistry, University of California at Irvine 92697, USA
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31
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Desdouits F, Buxbaum JD, Desdouits-Magnen J, Nairn AC, Greengard P. Amyloid beta peptide formation in cell-free preparations. Regulation by protein kinase C, calmodulin, and calcineurin. J Biol Chem 1996; 271:24670-4. [PMID: 8798734 DOI: 10.1074/jbc.271.40.24670] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Amyloid beta peptide (Abeta) is a short peptide that is the major constituent of the amyloid plaques and cerebrovascular amyloid deposits found in Alzheimer's disease. The lack of availability of a cell-free system in which to study Abeta formation has limited our understanding of the molecular mechanisms involved in its production. We report here the reconstitution of such a cell-free system. The reconstituted Abeta formation was temperature-dependent and required ATP. Preincubation with purified protein kinase C (PKC) induced a pronounced inhibition of Abeta formation, similar to that observed in intact cells upon stimulation of PKC. The calmodulin antagonists W-7 and trifluoperazine inhibited Abeta formation and enhanced the action of PKC in both the cell-free system and intact cells. A role for the calcium/calmodulin-activated protein phosphatase calcineurin in the regulation of Abeta formation was demonstrated using a specific peptide inhibitor of calcineurin in vitro as well as cyclosporin A, a cell-permeant inhibitor of calcineurin, in intact cells. Our results suggest that a single substrate might mediate opposing actions of PKC and calcineurin in the regulation of Abeta formation.
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Affiliation(s)
- F Desdouits
- Laboratory of Molecular and Cellular Neuroscience and the Zachary and Elizabeth M. Fisher Center for Research on Alzheimer Disease, The Rockefeller University, New York, New York 10021, USA
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