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Stock C, Schwab A. Ion channels and transporters in metastasis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:2638-46. [PMID: 25445667 DOI: 10.1016/j.bbamem.2014.11.012] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Revised: 11/03/2014] [Accepted: 11/07/2014] [Indexed: 12/23/2022]
Abstract
An elaborate interplay between ion channels and transporters, components of the cytoskeleton, adhesion molecules, and signaling cascades provides the basis for each major step of the metastatic cascade. Ion channels and transporters contribute to cell motility by letting through or transporting ions essential for local Ca2+, pH and--in cooperation with water permeable aquaporins--volume homeostasis. Moreover, in addition to the actual ion transport they, or their auxiliary subunits, can display non-conducting activities. They can exert kinase activity in order to phosphorylate cytoskeletal constituents or their associates. They can become part of signaling processes by permeating Ca2+, by generating local pH-nanodomains or by being final downstream effectors. A number of channels and transporters are found at focal adhesions, interacting directly or indirectly with proteins of the extracellular matrix, with integrins or with components of the cytoskeleton. We also include the role of aquaporins in cell motility. They drive the outgrowth of lamellipodia/invadopodia or control the number of β1 integrins in the plasma membrane. The multitude of interacting ion channels and transporters (called transportome) including the associated signaling events holds great potential as therapeutic target(s) for anticancer agents that are aimed at preventing metastasis. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.
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Affiliation(s)
- Christian Stock
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany.
| | - Albrecht Schwab
- Institute of Physiology II, University of Münster, Robert-Koch-Str. 27b, D-48149 Münster, Germany
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Watcharasit P, Suntararuks S, Visitnonthachai D, Thiantanawat A, Satayavivad J. β-catenin involvement in arsenite-induced VEGF expression in neuroblastoma SH-SY5Y cells. ENVIRONMENTAL TOXICOLOGY 2014; 29:672-678. [PMID: 22859221 DOI: 10.1002/tox.21794] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2012] [Revised: 06/28/2012] [Accepted: 06/30/2012] [Indexed: 06/01/2023]
Abstract
Arsenic is a widespread contaminant in the environment especially in drinking water. Although it is a known carcinogen in human, the mechanism by which arsenic induces carcinogenesis is not well understood. Among several effects of arsenic, it has been suggested that arsenic-induced vascular endothelial growth factor (VEGF) expression plays a critical role in arsenic carcinogenesis. In the present study, we demonstrated that arsenite induced VEGF expression in neuroblastoma SH-SY5Y cells without induction of HIF-1α, a well-known transcriptional activator for VEGF suggesting that arsenite-induced VEGF expression in SH-SY5Y cells may not require HIF-1α activation. It has been reported that VEGF expression is regulated by multiple transcription factors including β-catenin. We therefore investigated whether β-catenin was involved in arsenite-induced VEGF expression in SH-SY5Y cells. Treatment of arsenite caused β-catenin accumulation in the nucleus. Additionally, arsenite treatment decreased the activity of GSK3, an enzyme that phosphorylates and targets β-catenin for degradation by proteasome, without activation of its upstream kinase, Akt. Inhibition of PI3K/Akt which negatively regulates GSK3 activity by LY294002 resulted in a decrease in arsenite-mediated β-catenin nuclear accumulation, and VEGF expression. These results suggested that β-catenin plays a role in arsenite-induced VEGF in SH-SY5Y cells, and the induction of β-catenin by arsenite is mediated by inhibition of GSK3 without activating its upstream kinase Akt.
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Affiliation(s)
- Piyajit Watcharasit
- Laboratory of Pharmacology, Chulabhorn Research Institute, 54 Kamphaeng Phet 6 Rd, Bangkok 10210, Thailand; Chulabhorn Graduate Institute, 54 Kamphaeng Phet 6 Rd, Bangkok 10210, Thailand; Center of Excellence on Environmental Health and Toxicology (EHT), Office of the Higher Education Commission, Thailand
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Anastasio TJ. Computational identification of potential multitarget treatments for ameliorating the adverse effects of amyloid-β on synaptic plasticity. Front Pharmacol 2014; 5:85. [PMID: 24847263 PMCID: PMC4021136 DOI: 10.3389/fphar.2014.00085] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 04/07/2014] [Indexed: 11/24/2022] Open
Abstract
The leading hypothesis on Alzheimer Disease (AD) is that it is caused by buildup of the peptide amyloid-β (Aβ), which initially causes dysregulation of synaptic plasticity and eventually causes destruction of synapses and neurons. Pharmacological efforts to limit Aβ buildup have proven ineffective, and this raises the twin challenges of understanding the adverse effects of Aβ on synapses and of suggesting pharmacological means to prevent them. The purpose of this paper is to initiate a computational approach to understanding the dysregulation by Aβ of synaptic plasticity and to offer suggestions whereby combinations of various chemical compounds could be arrayed against it. This data-driven approach confronts the complexity of synaptic plasticity by representing findings from the literature in a course-grained manner, and focuses on understanding the aggregate behavior of many molecular interactions. The same set of interactions is modeled by two different computer programs, each written using a different programming modality: one imperative, the other declarative. Both programs compute the same results over an extensive test battery, providing an essential crosscheck. Then the imperative program is used for the computationally intensive purpose of determining the effects on the model of every combination of ten different compounds, while the declarative program is used to analyze model behavior using temporal logic. Together these two model implementations offer new insights into the mechanisms by which Aβ dysregulates synaptic plasticity and suggest many drug combinations that potentially may reduce or prevent it.
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Affiliation(s)
- Thomas J Anastasio
- Department of Molecular and Integrative Physiology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign Urbana, IL, USA
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Choong G, Liu Y, Templeton DM. Interplay of calcium and cadmium in mediating cadmium toxicity. Chem Biol Interact 2014; 211:54-65. [PMID: 24463198 DOI: 10.1016/j.cbi.2014.01.007] [Citation(s) in RCA: 161] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 12/31/2013] [Accepted: 01/13/2014] [Indexed: 01/30/2023]
Abstract
The environmentally important toxic metal, cadmium, exists as the Cd(2+) ion in biological systems, and in this state structurally resembles Ca(2+). Thus, although cadmium exerts a broad range of adverse actions on cells by virtue of its propensity to bind to protein thiol groups, it is now well appreciated that Cd(2+) participates in a number of Ca(2+)-dependent pathways, attributable to its actions as a Ca(2+) mimetic, with a central role for calmodulin, and the Ca(2+)/calmodlin-dependent protein kinase II (CaMK-II) that mediates effects on cytoskeletal dynamics and apoptotic cell death. Cadmium interacts with receptors and ion channels on the cell surface, and with the intracellular estrogen receptor where it binds competitively to residues shared by Ca(2+). It increases cytosolic [Ca(2+)] through several mechanisms, but also decreases transcript levels of some Ca(2+)-transporter genes. It initiates mitochondrial apoptotic pathways, and activates calpains, contributing to mitochondria-independent apoptosis. However, the recent discovery of the role CaMK-II plays in Cd(2+)-induced cell death, and subsequent implication of CaMK-II in Cd(2+)-dependent alterations of cytoskeletal dynamics, has opened a new area of mechanistic cadmium toxicology that is a focus of this review. Calmodulin is necessary for induction of apoptosis by several agents, yet induction of apoptosis by Cd(2+) is prevented by CaMK-II block, and Ca(2+)-dependent phosphorylation of CaMK-II has been linked to increased Cd(2+)-dependent apoptosis. Calmodulin antagonism suppresses Cd(2+)-induced phosphorylation of Erk1/2 and the Akt survival pathway. The involvement of CaMK-II in the effects of Cd(2+) on cell morphology, and particularly the actin cytoskeleton, is profound, favouring actin depolymerization, disrupting focal adhesions, and directing phosphorylated FAK into a cellular membrane. CaMK-II is also implicated in effects of Cd(2+) on microtubules and cadherin junctions. A key question for future cadmium research is whether cytoskeletal disruption leads to apoptosis, or rather if apoptosis initiates cytoskeletal disruption in the context of Cd(2+).
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Affiliation(s)
- Grace Choong
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto M5S 1A8, Canada
| | - Ying Liu
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto M5S 1A8, Canada
| | - Douglas M Templeton
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto M5S 1A8, Canada.
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Perreault ML, O'Dowd BF, George SR. Dopamine D1-D2Receptor Heteromer Regulates Signaling Cascades Involved in Addiction: Potential Relevance to Adolescent Drug Susceptibility. Dev Neurosci 2014; 36:287-96. [DOI: 10.1159/000360158] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 01/30/2014] [Indexed: 11/19/2022] Open
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De Montigny A, Elhiri I, Allyson J, Cyr M, Massicotte G. NMDA reduces Tau phosphorylation in rat hippocampal slices by targeting NR2A receptors, GSK3β, and PKC activities. Neural Plast 2013; 2013:261593. [PMID: 24349798 PMCID: PMC3856160 DOI: 10.1155/2013/261593] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 09/11/2013] [Indexed: 01/06/2023] Open
Abstract
The molecular mechanisms that regulate Tau phosphorylation are complex and currently incompletely understood. In the present study, pharmacological inhibitors were deployed to investigate potential processes by which the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors modulates Tau phosphorylation in rat hippocampal slices. Our results demonstrated that Tau phosphorylation at Ser199-202 residues was decreased in NMDA-treated hippocampal slices, an effect that was not reproduced at Ser262 and Ser404 epitopes. NMDA-induced reduction of Tau phosphorylation at Ser199-202 was further promoted when NR2A-containing receptors were pharmacologically isolated and were completely abrogated by the NR2A receptor antagonist NVP-AAM077. Compared with nontreated slices, we observed that NMDA receptor activation was reflected in high Ser9 and low Tyr216 phosphorylation of glycogen synthase kinase-3 beta (GSK3β), suggesting that NMDA receptor activation might diminish Tau phosphorylation via a pathway involving GSK3β inhibition. Accordingly, we found that GSK3β inactivation by a protein kinase C- (PKC-) dependent mechanism is involved in the NMDA-induced reduction of Tau phosphorylation at Ser199-202 epitopes. Taken together, these data indicate that NR2A receptor activation may be important in limiting Tau phosphorylation by a PKC/GSK3β pathway and strengthen the idea that these receptors might act as an important molecular device counteracting neuronal cell death mechanisms in various pathological conditions.
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Affiliation(s)
- Audrée De Montigny
- Groupe de Recherche en Neuroscience, Département de Biologie Médicale, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada G9A 5H7
| | - Ismaël Elhiri
- Groupe de Recherche en Neuroscience, Département de Biologie Médicale, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada G9A 5H7
| | - Julie Allyson
- Groupe de Recherche en Neuroscience, Département de Biologie Médicale, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada G9A 5H7
| | - Michel Cyr
- Groupe de Recherche en Neuroscience, Département de Biologie Médicale, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada G9A 5H7
| | - Guy Massicotte
- Groupe de Recherche en Neuroscience, Département de Biologie Médicale, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada G9A 5H7
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Wei H, Yao X, Yang L, Wang S, Guo F, Zhou H, Marsicano G, Wang Q, Xiong L. Glycogen synthase kinase-3β is involved in electroacupuncture pretreatment via the cannabinoid CB1 receptor in ischemic stroke. Mol Neurobiol 2013; 49:326-36. [PMID: 23943518 DOI: 10.1007/s12035-013-8524-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Accepted: 07/24/2013] [Indexed: 01/10/2023]
Abstract
We have previously shown that electroacupuncture (EA) pretreatment produces neuroprotective effects, which were mediated through an endocannabinoid signal transduction mechanism. Herein, we have studied the possible contribution of the phosphorylated form of glycogen synthase kinase-3β (GSK-3β) in EA pretreatment-induced neuroprotection via the cannabinoid CB1 receptor (CB1R). Focal transient cerebral ischemia was induced by middle cerebral artery occlusion in rats. Phosphorylation of GSK-3β at Ser-9 [p-GSK-3β (Ser-9)] was evaluated in the penumbra tissue following reperfusion. Infarct size and neurological score were assessed in the presence of either PI3K inhibitors or a GSK-3β inhibitor 72 h after reperfusion. Cellular apoptosis was evidenced by TUNEL staining and determination of the Bax/Bcl-2 ratio 24 h after reperfusion. The present study showed that EA pretreatment increased p-GSK-3β(Ser-9) 2 h after reperfusion in the ipsilateral penumbra. Augmented phosphorylation of GSK-3β induced similar neuroprotective effects as did EA pretreatment. By contrast, inhibition of PI3K dampened the levels of p-GSK-3β(Ser-9), and reversed not only the neuroprotective effect but also the anti-apoptotic effect following EA pretreatment. Regulation of GSK-3β by EA pretreatment was abolished following treatment with a CB1R antagonist and CB1R knockdown, whereas two CB1R agonists enhanced the phosphorylation of GSK-3β. Therefore we conclude that EA pretreatment protects against cerebral ischemia/reperfusion injury through CB1R-mediated phosphorylation of GSK-3β.
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Affiliation(s)
- Haidong Wei
- Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University, Xi'an, 710032, Shaanxi, China
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58
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Schofield AV, Gamell C, Bernard O. Tubulin polymerization promoting protein 1 (TPPP1) increases β-catenin expression through inhibition of HDAC6 activity in U2OS osteosarcoma cells. Biochem Biophys Res Commun 2013; 436:571-7. [PMID: 23727580 DOI: 10.1016/j.bbrc.2013.05.076] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 05/17/2013] [Indexed: 10/26/2022]
Abstract
The Rho-associated coiled-coil kinase (ROCK) family of proteins, including ROCK1 and ROCK2, are key regulators of actin and intermediate filament morphology. The newly discovered ROCK substrate Tubulin polymerization promoting protein 1 (TPPP1) promotes microtubule polymerization and inhibits the activity of Histone deacetylase 6 (HDAC6). The effect of TPPP1 on HDAC6 activity is inhibited by ROCK signaling. Moreover, it was recently demonstrated that ROCK activity increases the cellular expression of the oncogene β-catenin, which is a HDAC6 substrate. In this study, we investigated the interplay between ROCK-TPPP1-HDAC6 signaling and β-catenin expression. We demonstrate that β-catenin expression is increased with ROCK signaling activation and is reduced with increased TPPP1 expression in U2OS cells. Further investigation revealed that ROCK-mediated TPPP1 phosphorylation, which prevents its binding to HDAC6, negates TPPP1-mediated reduction in β-catenin expression. We also show that increased HDAC6 activity resulting from ROCK signaling activation reduced β-catenin acetylation at Lys-49, which was also accompanied by its decreased phosphorylation by Caesin kinase 1 (CK1) and Glycogen synthase kinase 3β (GSK3β), thus preventing its proteasomal degradation. Overall, our results suggest that ROCK regulates β-catenin stability in cells via preventing TPPP1-mediated inhibition of HDAC6 activity, to reduce its acetylation and degradation via phosphorylation by CK1 and GSK3β.
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Affiliation(s)
- Alice V Schofield
- Cytoskeleton and Cancer Unit, St. Vincent's Institute of Medical Research, Australia
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Protective effect of creatine against 6-hydroxydopamine-induced cell death in human neuroblastoma SH-SY5Y cells: Involvement of intracellular signaling pathways. Neuroscience 2013; 238:185-94. [DOI: 10.1016/j.neuroscience.2013.02.030] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 02/15/2013] [Accepted: 02/15/2013] [Indexed: 11/18/2022]
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Aversa Z, Alamdari N, Castillero E, Muscaritoli M, Fanelli FR, Hasselgren PO. CaMKII activity is reduced in skeletal muscle during sepsis. J Cell Biochem 2013; 114:1294-305. [DOI: 10.1002/jcb.24469] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 11/27/2012] [Indexed: 12/23/2022]
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61
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KCNN4 channels participate in the EMT induced by PRL-3 in colorectal cancer. Med Oncol 2013; 30:566. [PMID: 23572150 DOI: 10.1007/s12032-013-0566-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 03/30/2013] [Indexed: 02/08/2023]
Abstract
Studies have shown that phosphatase of regenerating liver-3 (PRL-3) promotes the invasion, migration, and metastasis of human tumor cells by facilitating an epithelial-mesenchymal transition (EMT). However, the mechanism by which PRL-3 induces tumor cell EMT is unknown. Our previous research revealed that PRL-3 promotes LoVo cell proliferation by up-regulating KCNN4 channels. In the current study, we explored the mechanism by which PRL-3 mediates EMT. We demonstrated that PRL-3 induced the expression of KCNN4 channels, leading to EMT and the down-regulation of E-cadherin. Further studies revealed that KCNN4 channels increased intracellular calcium levels and activated components of cell signaling downstream of calcium, including CaM-kinase II and glycogen synthase kinase-3 beta (GSK-3 beta), which increased Snail expression. Inhibiting KCNN4 with siRNA and TRAM-34, a specific inhibitor, restored E-cadherin expression and inhibited Snail expression. These results implicated the up-regulation of KCNN4 channels in the PRL-3-mediated induction of EMT and promotion of cancer metastasis.
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Tan M, Ma S, Huang Q, Hu K, Song B, Li M. GSK-3α/β-mediated phosphorylation of CRMP-2 regulates activity-dependent dendritic growth. J Neurochem 2013; 125:685-97. [PMID: 23470087 DOI: 10.1111/jnc.12230] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 02/25/2013] [Accepted: 02/28/2013] [Indexed: 12/15/2022]
Abstract
Neuronal activity shapes the dendritic arbour; however, most of the molecular players in this process remain to be identified. We observed that depolarization-induced neuronal activity causes an increase in the phosphorylation of glycogen synthase kinase-3 (GSK-3)α/β on Ser21/9 in cerebellar granule neurons. Using several approaches, including gene knockdown and GSK-3α/β(S21A/S21A/S9A/S9A) double knockin mice, we demonstrated that both GSK-3β and GSK-3α mediate activity-dependent dendritic growth and that Ser21/9 phosphorylation of GSK-3α/β plays an important role in this process. Collapsin response mediator protein-2 (CRMP-2), which is crucial for axon development, is phosphorylated at Thr514 and inactivated by GSK-3. We found CRMP-2 was located mainly in the dendrites of cerebellar granule neurons, in contrast to the axonal distribution in hippocampal neurons. Over-expression of CRMP-2 promoted and knockdown of CRMP-2 impaired dendritic growth, suggesting that CRMP-2 is necessary and sufficient for activity-dependent dendritic development. Furthermore, silencing CRMP-2 completely blocked the dendritic growth-promoting effects of GSK-3 knockdown, and expression of Thr514 nonphosphorylated form of CRMP-2 counteracted the inhibitory effect of constitutively active GSK-3. This data indicate that CRMP-2 functions downstream of GSK-3. Together, these findings identify a novel GSK-3/CRMP-2 pathway that connects neuronal activity to dendritic growth.
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Affiliation(s)
- Minghui Tan
- Department of Pharmacology and the Proteomics Center, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
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Naringin Enhances CaMKII Activity and Improves Long-Term Memory in a Mouse Model of Alzheimer's Disease. Int J Mol Sci 2013; 14:5576-86. [PMID: 23478434 PMCID: PMC3634479 DOI: 10.3390/ijms14035576] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 02/04/2013] [Accepted: 02/16/2013] [Indexed: 12/30/2022] Open
Abstract
The Amyloid-β (Aβ)-induced impairment of hippocampal synaptic plasticity is an underlying mechanism of memory loss in the early stages of Alzheimer’s disease (AD) in human and mouse models. The inhibition of the calcium/calmodulin-dependent protein kinase II (CaMKII) autophosphorylation plays an important role in long-term memory. In this study, we isolated naringin from Pomelo peel (a Citrus species) and studied its effect on long-term memory in the APPswe/PS1dE9 transgenic mouse model of AD. Three-month-old APPswe/PS1dE9 transgenic mice were randomly assigned to a vehicle group, two naringin (either 50 or 100 mg/kg body weight/day) groups, or an Aricept (2 mg/kg body weight/day) group. After 16 weeks of treatment, we observed that treatment with naringin (100 mg/kg body weight/day) enhanced the autophosphorylation of CaMKII, increased the phosphorylation of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA) receptor at a CaMKII-dependent site and improved long-term learning and memory ability. These findings suggest that the increase in CaMKII activity may be one of the mechanisms by which naringin improves long-term cognitive function in the APPswe/PS1dE9 transgenic mouse model of AD.
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Avrahami L, Farfara D, Shaham-Kol M, Vassar R, Frenkel D, Eldar-Finkelman H. Inhibition of glycogen synthase kinase-3 ameliorates β-amyloid pathology and restores lysosomal acidification and mammalian target of rapamycin activity in the Alzheimer disease mouse model: in vivo and in vitro studies. J Biol Chem 2012; 288:1295-306. [PMID: 23155049 DOI: 10.1074/jbc.m112.409250] [Citation(s) in RCA: 173] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Accumulation of β-amyloid (Aβ) deposits is a primary pathological feature of Alzheimer disease that is correlated with neurotoxicity and cognitive decline. The role of glycogen synthase kinase-3 (GSK-3) in Alzheimer disease pathogenesis has been debated. To study the role of GSK-3 in Aβ pathology, we used 5XFAD mice co-expressing mutated amyloid precursor protein and presenilin-1 that develop massive cerebral Aβ loads. Both GSK-3 isozymes (α/β) were hyperactive in this model. Nasal treatment of 5XFAD mice with a novel substrate competitive GSK-3 inhibitor, L803-mts, reduced Aβ deposits and ameliorated cognitive deficits. Analyses of 5XFAD hemi-brain samples indicated that L803-mts restored the activity of mammalian target of rapamycin (mTOR) and inhibited autophagy. Lysosomal acidification was impaired in the 5XFAD brains as indicated by reduced cathepsin D activity and decreased N-glycoyslation of the vacuolar ATPase subunit V0a1, a modification required for lysosomal acidification. Treatment with L803-mts restored lysosomal acidification in 5XFAD brains. Studies in SH-SY5Y cells confirmed that GSK-3α and GSK-3β impair lysosomal acidification and that treatment with L803-mts enhanced the acidic lysosomal pool as demonstrated in LysoTracker Red-stained cells. Furthermore, L803-mts restored impaired lysosomal acidification caused by dysfunctional presenilin-1. We provide evidence that mTOR is a target activated by GSK-3 but inhibited by impaired lysosomal acidification and elevation in amyloid precursor protein/Aβ loads. Taken together, our data indicate that GSK-3 is a player in Aβ pathology. Inhibition of GSK-3 restores lysosomal acidification that in turn enables clearance of Aβ burdens and reactivation of mTOR. These changes facilitate amelioration in cognitive function.
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Affiliation(s)
- Limor Avrahami
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, George S. Wise Faculty of Life Sciences, Tel Aviv University Tel Aviv 69978, Israel
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Ma S, Liu S, Huang Q, Xie B, Lai B, Wang C, Song B, Li M. Site-specific phosphorylation protects glycogen synthase kinase-3β from calpain-mediated truncation of its N and C termini. J Biol Chem 2012; 287:22521-32. [PMID: 22496446 DOI: 10.1074/jbc.m111.321349] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Glycogen synthase kinase-3β (GSK-3β), a key regulator of neuronal apoptosis, is inhibited by the phosphorylation of Ser-9/Ser-389 and was recently shown to be cleaved by calpain at the N terminus, leading to its subsequent activation. In this study calpain was found to cleave GSK-3β not only at the N terminus but also at the C terminus, and cleavage sites were identified at residues Thr-38-Thr-39 and Ile-384-Gln-385. Furthermore, the cleavage of GSK-3β occurred in tandem with Ser-9 dephosphorylation during cerebellar granule neuron apoptosis. Increasing Ser-9 phosphorylation of GSK-3β by inhibiting phosphatase 1/2A or pretreating with purified active Akt inhibited calpain-mediated cleavage of GSK-3β at both N and C termini, whereas non-phosphorylatable mutant GSK-3β S9A facilitated its cleavage. In contrast, Ser-389 phosphorylation selectively inhibited the cleavage of GSK-3β at the C terminus but not the N terminus. Calpain-mediated cleavage resulted in three truncated products, all of which contained an intact kinase domain: ΔN-GSK-3β (amino acids 39-420), ΔC-GSK-3β (amino acids 1-384), and ΔN/ΔC-GSK-3β (amino acids 39-384). All three truncated products showed increased kinase and pro-apoptotic activity, with ΔN/ΔC-GSK-3β being the most active form. This observation suggests that the GSK-3β C terminus acts as an autoinhibitory domain similar to the N terminus. Taken together, these findings demonstrate that calpain-mediated cleavage activates GSK-3β by removing its N- and C-terminal autoinhibitory domains and that Ser-9 phosphorylation inhibits the cleavage of GSK-3β at both termini. In contrast, Ser-389 phosphorylation inhibits only C-terminal cleavage but not N-terminal cleavage. These findings also identify a mechanism by which site-specific phosphorylation and calpain-mediated cleavage operate in concert to regulate GSK-3β activity.
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Affiliation(s)
- Shanshan Ma
- Department of Pharmacology and Proteomics Center, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan Road II, Guangzhou 510080, China
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Migración neuronal, apoptosis y trastorno bipolar. REVISTA DE PSIQUIATRIA Y SALUD MENTAL 2012; 5:127-33. [DOI: 10.1016/j.rpsm.2011.11.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 11/12/2011] [Accepted: 11/28/2011] [Indexed: 11/23/2022]
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Bradley CA, Peineau S, Taghibiglou C, Nicolas CS, Whitcomb DJ, Bortolotto ZA, Kaang BK, Cho K, Wang YT, Collingridge GL. A pivotal role of GSK-3 in synaptic plasticity. Front Mol Neurosci 2012; 5:13. [PMID: 22363262 PMCID: PMC3279748 DOI: 10.3389/fnmol.2012.00013] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Accepted: 01/31/2012] [Indexed: 01/01/2023] Open
Abstract
Glycogen synthase kinase-3 (GSK-3) has many cellular functions. Recent evidence suggests that it plays a key role in certain types of synaptic plasticity, in particular a form of long-term depression (LTD) that is induced by the synaptic activation of N-methyl-D-aspartate receptors (NMDARs). In the present article we summarize what is currently known concerning the roles of GSK-3 in synaptic plasticity at both glutamatergic and GABAergic synapses. We summarize its role in cognition and speculate on how alterations in the synaptic functioning of GSK-3 may be a major factor in certain neurodegenerative disorders.
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c-Jun induction is independent of early growth response factor during cerebellar granule neuron apoptosis. Neuroreport 2012; 23:67-72. [DOI: 10.1097/wnr.0b013e32834e7d69] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Zhao L, Wang F, Gui B, Hua F, Qian Y. Prophylactic lithium alleviates postoperative cognition impairment by phosphorylating hippocampal glycogen synthase kinase-3β (Ser9) in aged rats. Exp Gerontol 2011; 46:1031-6. [DOI: 10.1016/j.exger.2011.09.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2011] [Revised: 08/24/2011] [Accepted: 09/06/2011] [Indexed: 12/31/2022]
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Abstract
Ischemic insults on neurons trigger excessive, pathological glutamate release that causes Ca²⁺ overload resulting in neuronal cell death (excitotoxicity). The Ca²⁺/calmodulin (CaM)-dependent protein kinase II (CaMKII) is a major mediator of physiological excitatory glutamate signals underlying neuronal plasticity and learning. Glutamate stimuli trigger autophosphorylation of CaMKII at T286, a process that makes the kinase "autonomous" (partially active independent from Ca²⁺ stimulation) and that is required for forms of synaptic plasticity. Recent studies suggested autonomous CaMKII activity also as potential drug target for post-insult neuroprotection, both after glutamate insults in neuronal cultures and after focal cerebral ischemia in vivo. However, CaMKII and other members of the CaM kinase family have been implicated in regulation of both neuronal death and survival. Here, we discuss past findings and possible mechanisms of CaM kinase functions in excitotoxicity and cerebral ischemia, with a focus on CaMKII and its regulation.
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Harashima SI, Wang Y, Horiuchi T, Seino Y, Inagaki N. Purkinje cell protein 4 positively regulates neurite outgrowth and neurotransmitter release. J Neurosci Res 2011; 89:1519-30. [PMID: 21671256 DOI: 10.1002/jnr.22688] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2010] [Revised: 04/08/2011] [Accepted: 04/11/2011] [Indexed: 11/06/2022]
Abstract
Purkinje cell protein 4 (PCP4), also called brain-specific polypeptide 19 (PEP19), is a neurospecific, small calmodulin-binding protein that binds both calcium-free and calcium-binding calmodulin to regulate the calmodulin-mediated signal. The expression level of this molecule is decreased in the brain in Alzheimer's disease, Huntington's disease, and alcoholism. However, little is known of the function of PCP4 regarding neuronal or neuroendocrine cell differentiation and neurotransmitter release. To address this, we established a PCP4 tetracycline-inducible rat chromaffin cell line, PC12. When PCP4 expression was induced with doxcycline, neurite outgrowth was significantly advanced in the presence of nerve growth factor (NGF) and dibutyryl cAMP, which was inhibited by W-7, a calmodulin inhibitor, and PD98059, an ERK inhibitor. In addition, size of the cell body also was increased by treatment with NGF in the PCP4-induced PC12 cells. Constitutive and potassium-evoked release of acetylcholine and dopamine was increased and apoptosis induced by hydrogen peroxide (H(2)O(2)) was inhibited in PCP4-induced PC12 cells. On the other hand, knockdown of PCP4 by siRNA transfection decreased neurite outgrowth and dopamine release and increased H(2)O(2)-induced apoptosis in PC12 cells. These results indicate that PCP4 promotes neuroendocrine cell differentiation and neurotransmitter release by activating calmodulin function.
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Affiliation(s)
- Shin-ichi Harashima
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
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Abstract
The proapoptotic BH3-only protein Bim is a crucial regulator of neuronal apoptosis. Previous studies have indicated the involvement of the c-Jun, FOXO1/3a, and B/C-Myb transcription factors in the regulation of Bim during neuronal apoptosis. However, the mechanism underlying the transcriptional regulation of Bim in activity deprivation-induced neuronal apoptosis has remained unclear. The present study demonstrates that early growth response 1 (Egr-1), rather than c-Jun, FOXO1/3a, or B/C-Myb, directly transactivates Bim gene expression to mediate apoptosis of rat cerebellar granule neurons. We showed that Egr-1 was sufficient and necessary for neuronal apoptosis. Suppression of Egr-1 activity using dominant-negative mutant or knockdown of Egr-1 using small interfering RNAs led to a decrease in Bim expression, whereas overexpression of Egr-1 resulted in induction of Bim. Deletion and site-directed mutagenesis of the Bim promoter revealed that Bim transcriptional activation depends primarily on a putative Egr-binding sequence between nucleotides -56 and -47 upstream of the start site. We also showed that Egr-1 binding to this sequence increased in response to activity deprivation in vitro and in vivo. Moreover, inhibition of Egr-1 binding to the Bim promoter, by mithramycin A and chromomycin A3, reduced the activity deprivation-induced increases in Bim promoter activity and mRNA and protein levels and protected neurons from apoptosis, further supporting the Egr-1-mediated transactivation of Bim. Additionally, Bim overcame the Egr-1 knockdown-mediated inhibition of apoptosis, whereas Bim knockdown impaired the increase in apoptosis induced by Egr-1. These findings establish Bim as an Egr-1 target gene in neurons, uncovering a novel Egr-1/Bim pathway by which activity deprivation induces neuronal apoptosis.
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Smillie KJ, Cousin MA. The Role of GSK3 in Presynaptic Function. Int J Alzheimers Dis 2011; 2011:263673. [PMID: 21547219 PMCID: PMC3087464 DOI: 10.4061/2011/263673] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 01/20/2011] [Indexed: 11/20/2022] Open
Abstract
The past ten years of research have identified a number of key roles for glycogen synthase kinase 3 (GSK3) at the synapse. In terms of presynaptic physiology, critical roles for GSK3 have been revealed in the growth and maturation of the nerve terminal and more recently a key role in the control of activity-dependent bulk endocytosis of synaptic vesicles. This paper will summarise the major roles assigned to GSK3 in both immature and mature nerve terminals, the substrates GSK3 phosphorylates to exert its action, and how GSK3 activity is regulated by different presynaptic signalling cascades. The number of essential roles for GSK3, coupled with the numerous signalling cascades all converging to regulate its activity, suggests that GSK3 is a key integrator of multiple inputs to modulate the strength of neurotransmission. Modulation of these pathways may point to potential mechanisms to overcome synaptic failure in neurodegenerative disorders such as Alzheimer's disease.
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Affiliation(s)
- Karen Janet Smillie
- Membrane Biology Group, Centre for Integrative Physiology, University of Edinburgh, George Square, EH8 9XD, Edinburgh, UK
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