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Martínez Cué C, Dierssen M. Plasticity as a therapeutic target for improving cognition and behavior in Down syndrome. PROGRESS IN BRAIN RESEARCH 2020; 251:269-302. [DOI: 10.1016/bs.pbr.2019.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Del Hoyo L, Xicota L, Langohr K, Sánchez-Benavides G, de Sola S, Cuenca-Royo A, Rodriguez J, Rodríguez-Morató J, Farré M, Dierssen M, de la Torre R. VNTR-DAT1 and COMTVal158Met Genotypes Modulate Mental Flexibility and Adaptive Behavior Skills in Down Syndrome. Front Behav Neurosci 2016; 10:193. [PMID: 27799900 PMCID: PMC5065956 DOI: 10.3389/fnbeh.2016.00193] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 09/26/2016] [Indexed: 02/02/2023] Open
Abstract
Down syndrome (DS) is an aneuploidy syndrome that is caused by trisomy for human chromosome 21 resulting in a characteristic cognitive and behavioral phenotype, which includes executive functioning and adaptive behavior difficulties possibly due to prefrontal cortex (PFC) deficits. DS also present a high risk for early onset of Alzheimer Disease-like dementia. The dopamine (DA) system plays a neuromodulatory role in the activity of the PFC. Several studies have implicated trait differences in DA signaling on executive functioning based on genetic polymorphisms in the genes encoding for the catechol-O-methyltransferase (COMTVal158Met) and the dopamine transporter (VNTR-DAT1). Since it is known that the phenotypic consequences of genetic variants are modulated by the genetic background in which they occur, we here explore whether these polymorphisms variants interact with the trisomic genetic background to influence gene expression, and how this in turn mediates DS phenotype variability regarding PFC cognition. We genotyped 69 young adults of both genders with DS, and found that VNTR-DAT1 was in Hardy-Weinberg equilibrium but COMTVal158Met had a reduced frequency of Met allele homozygotes. In our population, genotypes conferring higher DA availability, such as Met allele carriers and VNTR-DAT1 10-repeat allele homozygotes, resulted in improved performance in executive function tasks that require mental flexibility. Met allele carriers showed worse adaptive social skills and self-direction, and increased scores in the social subscale of the Dementia Questionnaire for People with Intellectual Disabilities than Val allele homozygotes. The VNTR-DAT1 was not involved in adaptive behavior or early dementia symptoms. Our results suggest that genetic variants of COMTVal158Met and VNTR-DAT1 may contribute to PFC-dependent cognition, while only COMTVal158Met is involved in behavioral phenotypes of DS, similar to euploid population.
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Affiliation(s)
- Laura Del Hoyo
- Integrative Pharmacology and Systems Neuroscience Group, Neurosciences Research Program, IMIM-Hospital del Mar Medical Research InstituteBarcelona, Spain; Departament de Farmacologia, de Terapèutica i de Toxicologia, Universidad Autónoma de BarcelonaBarcelona, Spain
| | - Laura Xicota
- Integrative Pharmacology and Systems Neuroscience Group, Neurosciences Research Program, IMIM-Hospital del Mar Medical Research InstituteBarcelona, Spain; Cellular & Systems Neurobiology, Systems Biology Program, Centre for Genomic Regulation, The Barcelona Institute of Science and TechnologyBarcelona, Spain; Department of Experimental and Health Sciences, Universidad Pompeu FabraBarcelona, Spain
| | - Klaus Langohr
- Integrative Pharmacology and Systems Neuroscience Group, Neurosciences Research Program, IMIM-Hospital del Mar Medical Research InstituteBarcelona, Spain; Department of Statistics and Operations Research, Universidad Politècnica de Cataluña/BarcelonaTechBarcelona, Spain
| | - Gonzalo Sánchez-Benavides
- Integrative Pharmacology and Systems Neuroscience Group, Neurosciences Research Program, IMIM-Hospital del Mar Medical Research Institute Barcelona, Spain
| | - Susana de Sola
- Integrative Pharmacology and Systems Neuroscience Group, Neurosciences Research Program, IMIM-Hospital del Mar Medical Research InstituteBarcelona, Spain; Cellular & Systems Neurobiology, Systems Biology Program, Centre for Genomic Regulation, The Barcelona Institute of Science and TechnologyBarcelona, Spain
| | - Aida Cuenca-Royo
- Integrative Pharmacology and Systems Neuroscience Group, Neurosciences Research Program, IMIM-Hospital del Mar Medical Research Institute Barcelona, Spain
| | - Joan Rodriguez
- Integrative Pharmacology and Systems Neuroscience Group, Neurosciences Research Program, IMIM-Hospital del Mar Medical Research Institute Barcelona, Spain
| | - Jose Rodríguez-Morató
- Integrative Pharmacology and Systems Neuroscience Group, Neurosciences Research Program, IMIM-Hospital del Mar Medical Research InstituteBarcelona, Spain; Department of Experimental and Health Sciences, Universidad Pompeu FabraBarcelona, Spain; CIBER Fisiopatología Obesidad y Nutrición, Instituto Salud Carlos IIIMadrid, Spain
| | - Magí Farré
- Integrative Pharmacology and Systems Neuroscience Group, Neurosciences Research Program, IMIM-Hospital del Mar Medical Research InstituteBarcelona, Spain; Departament de Farmacologia, de Terapèutica i de Toxicologia, Universidad Autónoma de BarcelonaBarcelona, Spain
| | - Mara Dierssen
- Cellular & Systems Neurobiology, Systems Biology Program, Centre for Genomic Regulation, The Barcelona Institute of Science and TechnologyBarcelona, Spain; Department of Experimental and Health Sciences, Universidad Pompeu FabraBarcelona, Spain; CIBER de Enfermedades Raras, Instituto Salud Carlos IIIMadrid, Spain
| | - Rafael de la Torre
- Integrative Pharmacology and Systems Neuroscience Group, Neurosciences Research Program, IMIM-Hospital del Mar Medical Research InstituteBarcelona, Spain; Department of Experimental and Health Sciences, Universidad Pompeu FabraBarcelona, Spain; CIBER Fisiopatología Obesidad y Nutrición, Instituto Salud Carlos IIIMadrid, Spain
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Regulation of amyloid precursor protein processing by serotonin signaling. PLoS One 2014; 9:e87014. [PMID: 24466315 PMCID: PMC3897773 DOI: 10.1371/journal.pone.0087014] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 12/16/2013] [Indexed: 11/25/2022] Open
Abstract
Proteolytic processing of the amyloid precursor protein (APP) by the β- and γ-secretases releases the amyloid-β peptide (Aβ), which deposits in senile plaques and contributes to the etiology of Alzheimer's disease (AD). The α-secretase cleaves APP in the Aβ peptide sequence to generate soluble APPα (sAPPα). Upregulation of α-secretase activity through the 5-hydroxytryptamine 4 (5-HT4) receptor has been shown to reduce Aβ production, amyloid plaque load and to improve cognitive impairment in transgenic mouse models of AD. Consequently, activation of 5-HT4 receptors following agonist stimulation is considered to be a therapeutic strategy for AD treatment; however, the signaling cascade involved in 5-HT4 receptor-stimulated proteolysis of APP remains to be determined. Here we used chemical and siRNA inhibition to identify the proteins which mediate 5-HT4d receptor-stimulated α-secretase activity in the SH-SY5Y human neuronal cell line. We show that G protein and Src dependent activation of phospholipase C are required for α-secretase activity, while, unexpectedly, adenylyl cyclase and cAMP are not involved. Further elucidation of the signaling pathway indicates that inositol triphosphate phosphorylation and casein kinase 2 activation is also a prerequisite for α-secretase activity. Our findings provide a novel route to explore the treatment of AD through 5-HT4 receptor-induced α-secretase activation.
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A commentary on: Overexpression of Dyrk1A inhibits choline acetyltransferase induction by oleic acid in cellular models of Down syndrome. Exp Neurol 2013; 247:110-2. [DOI: 10.1016/j.expneurol.2013.03.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 03/31/2013] [Indexed: 11/21/2022]
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Mouse models of Down syndrome as a tool to unravel the causes of mental disabilities. Neural Plast 2012; 2012:584071. [PMID: 22685678 PMCID: PMC3364589 DOI: 10.1155/2012/584071] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 03/23/2012] [Accepted: 03/24/2012] [Indexed: 12/16/2022] Open
Abstract
Down syndrome (DS) is the most common genetic cause of mental disability. Based on the homology of Hsa21 and the murine chromosomes Mmu16, Mmu17 and Mmu10, several mouse models of DS have been developed. The most commonly used model, the Ts65Dn mouse, has been widely used to investigate the neural mechanisms underlying the mental disabilities seen in DS individuals. A wide array of neuromorphological alterations appears to compromise cognitive performance in trisomic mice. Enhanced inhibition due to alterations in GABA(A)-mediated transmission and disturbances in the glutamatergic, noradrenergic and cholinergic systems, among others, has also been demonstrated. DS cognitive dysfunction caused by neurodevelopmental alterations is worsened in later life stages by neurodegenerative processes. A number of pharmacological therapies have been shown to partially restore morphological anomalies concomitantly with cognition in these mice. In conclusion, the use of mouse models is enormously effective in the study of the neurobiological substrates of mental disabilities in DS and in the testing of therapies that rescue these alterations. These studies provide the basis for developing clinical trials in DS individuals and sustain the hope that some of these drugs will be useful in rescuing mental disabilities in DS individuals.
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Baamonde C, Martínez-Cué C, Flórez J, Dierssen M. G-protein-associated signal transduction processes are restored after postweaning environmental enrichment in Ts65Dn, a Down syndrome mouse model. Dev Neurosci 2011; 33:442-50. [PMID: 21865666 DOI: 10.1159/000329425] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Accepted: 05/09/2011] [Indexed: 12/21/2022] Open
Abstract
Individuals with Down syndrome (DS) present cognitive deficits that can be improved by early implementation of special care programs. However, they showed limited and temporary cognitive effects. We previously demonstrated that postnatal environmental enrichment (EE) improved clearly, though temporarily, the execution of visuospatial memory tasks in Ts65Dn mice, a DS model bearing a partial trisomy of murine chromosome 16; but in contrast to wild-type littermates, there was a lack of structural plasticity in pyramidal cell structure in the trisomic cerebral cortex. In the present study, we have investigated the impact of EE on the function of adenylyl cyclase and phospholipase C as a possible mechanism underlying the time-limited improvements observed. Basal production of cyclic adenosine monophosphate (cAMP) was not affected, but responses to GTPγS, isoprenaline, noradrenaline, SKF 38393 and forskolin were depressed in the Ts65Dn hippocampus. In EE conditions, cAMP accumulation was not significantly modified in control animals with respect to nonenriched controls. However, EE had a marked effect in Ts65Dn mice, in which cAMP production was significantly increased. Similarly, EE increased phospholipase C activity in Ts65Dn mice, in response to carbachol and calcium. We conclude that EE restores the G-protein-associated signal transduction systems that are altered in Ts65Dn mice.
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Affiliation(s)
- C Baamonde
- Genes and Disease Program, Center for Genomic Regulation (CRG), Barcelona Biomedical Research Park (PRBB), and CIBER de Enfermedades Raras (CIBERER), Barcelona, Spain
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Faizi M, Bader PL, Tun C, Encarnacion A, Kleschevnikov A, Belichenko P, Saw N, Priestley M, Tsien RW, Mobley WC, Shamloo M. Comprehensive behavioral phenotyping of Ts65Dn mouse model of Down syndrome: activation of β1-adrenergic receptor by xamoterol as a potential cognitive enhancer. Neurobiol Dis 2011; 43:397-413. [PMID: 21527343 DOI: 10.1016/j.nbd.2011.04.011] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Revised: 04/04/2011] [Accepted: 04/11/2011] [Indexed: 12/16/2022] Open
Abstract
Down syndrome (DS) is the most prevalent form of mental retardation caused by genetic abnormalities in humans. This has been successfully modeled in mice to generate the Ts65Dn mouse, a genetic model of DS. This transgenic mouse model shares a number of physical and functional abnormalities with people with DS, including changes in the structure and function of neuronal circuits. Significant abnormalities in noradrenergic (NE-ergic) afferents from the locus coeruleus to the hippocampus, as well as deficits in NE-ergic neurotransmission are detected in these animals. In the current study we characterized in detail the behavioral phenotype of Ts65Dn mice, in addition to using pharmacological tools for identification of target receptors mediating the learning and memory deficits observed in this model of DS. We undertook a comprehensive approach to mouse phenotyping using a battery of standard and novel tests encompassing: (i) locomotion (Activity Chamber, PhenoTyper, and CatWalk), (ii) learning and memory (spontaneous alternation, delayed matching-to-place water maze, fear conditioning, and Intellicage), and (iii) social behavior. Ts65Dn mice showed increased locomotor activity in novel and home cage environments. There were significant and reproducible deficits in learning and memory tests including spontaneous alternation, delayed matching-to-place water maze, Intellicage place avoidance and contextual fear conditioning. Although Ts65Dn mice showed no deficit in sociability in the 3-chamber test, a marked impairment in social memory was detected. Xamoterol, a β1-adrenergic receptor (β1-ADR) agonist, effectively restored the memory deficit in contextual fear conditioning, spontaneous alternation and novel object recognition. These behavioral improvements were reversed by betaxolol, a selective β1-ADR antagonist. In conclusion, our results demonstrate that this mouse model of Down syndrome displays cognitive deficits which are mediated by an imbalance in the noradrenergic system. In this experimental model of Down syndrome a selective activation of β1-ADR does restore some of these behavioral deficits. Further mechanistic studies will be needed to investigate the failure of noradrenergic system and the role of β1-ADR in cognitive deficit and pathogenesis of DS in people. Restoring NE neurotransmission or a selective activation of β1)-ADR needs to be further investigated for the development of any potential therapeutic strategy for symptomatic relief of memory deficit in DS. Furthermore, due to the significant involvement of noradrenergic system in the cardiovascular function further safety and translational studies will be needed to ensure the safety and efficacy of this approach.
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Affiliation(s)
- Mehrdad Faizi
- Stanford Behavioral and Functional Neuroscience Laboratory, Stanford Institute for Neuro-Innovation and Translational Neurosciences, Stanford University School of Medicine, USA
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Zalduegui A, López de Jesús M, Callado LF, Meana JJ, Sallés J. Levels of Gsα(short and long), Gα(olf) and Gβ(common) subunits, and calcium-sensitive adenylyl cyclase isoforms (1, 5/6, 8) in post-mortem human brain caudate and cortical membranes: comparison with rat brain membranes and potential stoichiometric relationships. Neurochem Int 2010; 58:180-9. [PMID: 21115086 DOI: 10.1016/j.neuint.2010.11.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 11/12/2010] [Accepted: 11/21/2010] [Indexed: 11/24/2022]
Abstract
The levels of expression of Gsα(short and long), Gα(olf) and Gβ(common) subunits, and calcium-sensitive adenylyl cyclases isoforms (AC1, 5/6, and 8) in human brain cortical and caudate membranes were quantified by western blot analysis in order to establish their contribution to the patterns of AC functioning. Both areas expressed Gsα(long) (52 kDa) with values ranging from about 1400 ng/mg of membrane protein in cerebral cortex to close to 600 ng/mg of membrane protein in caudate nucleus. In contrast, Gsα(short) and Gsα(olf) were expressed separately, Gsα(short) in cortical membranes with values around 500 ng/mg of membrane protein and Gα(olf) in caudate membranes with values around 1300 ng/mg of membrane protein. Quantitative measurements of Gβ, revealed a similar expression level in cortical and caudate membranes (5444±732 versus 5511±394 ng/mg protein; p=0.966). The B(max) values of GTPγS-dependent [(3)H]-forskolin binding show the following descending order: rat striatal membranes>rat cortical membranes=human caudate membranes>human cortical membranes. Therefore, as measured immunochemically and by [(3)H]-forskolin binding, there seems to be a vast excess of Gsα subunits over catalytic units of AC. The highest levels of AC5/6 expression were detected in caudate membranes. AC8 was little expressed, and there were no significant differences in the relative values between both human brain regions. Finally, the levels of the AC1 isoform were significantly lower in caudate than in cortical membranes. It is concluded that these stoichiometric data contribute nonetheless to explain the significant differences observed in signalling capacities through the AC system in both human brain regions.
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Affiliation(s)
- Amaia Zalduegui
- Department of Pharmacology, Faculty of Pharmacy (Vitoria-Gasteiz), University of the Basque Country (UPV/EHU), Spain
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Shamloo M, Belichenko PV, Mobley WC. Comprehensive behavioral assays to enhance phenotype to genotype linkages and therapeutic screening in mouse models of Down syndrome. FUTURE NEUROLOGY 2010. [DOI: 10.2217/fnl.10.29] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Mehrdad Shamloo
- Behavioral & Functional Neuroscience Laboratory, Institute for Neuro-Innovation & Translational Neurosciences, Stanford University School of Medicine, CA, USA
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Arqué G, de Lagrán MM, Arbonés ML, Dierssen M. Age-associated motor and visuo-spatial learning phenotype in Dyrk1A heterozygous mutant mice. Neurobiol Dis 2009; 36:312-9. [PMID: 19660545 DOI: 10.1016/j.nbd.2009.07.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 07/27/2009] [Accepted: 07/28/2009] [Indexed: 01/08/2023] Open
Abstract
Dual-specificity tyrosine-regulated kinase 1A (DYRK1A) is a candidate gene for the Down syndrome neurological defects and may be involved in the progression of Alzheimer's disease. Heterozygous mice for Dyrk1A (Dyrk1A+/-) exhibit decreased brain size, motor abnormalities and cognitive deficits in the adult. However, there is no information about the mutant phenotype in old ages. Here we analyze the impact of Dyrk1A dosage reduction on motor performance and hippocampal-dependent learning and memory in aged Dyrk1A+/- mice. Whereas motor tests showed marked alterations in traction ability, prehensile reflex and balance, heterozygous mice only present a slight impairment of visuo-spatial memory even though they show a robust decrease of CA1-CA3 and dentate gyrus cells.
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Affiliation(s)
- Glòria Arqué
- Genes and Disease Program, Center for Genomic Regulation (CRG), Pompeu Fabra University, Barcelona Biomedical Research Park (PRBB) and CIBER de Enfermedades Raras (CIBERER), Barcelona, Spain
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Azkona G, Amador-Arjona A, Obradors-Tarragó C, Varea E, Arqué G, Pinacho R, Fillat C, de la Luna S, Estivill X, Dierssen M. Characterization of a mouse model overexpressing beta-site APP-cleaving enzyme 2 reveals a new role for BACE2. GENES BRAIN AND BEHAVIOR 2009; 9:160-72. [PMID: 19840121 DOI: 10.1111/j.1601-183x.2009.00538.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACE2 is homologous to BACE1, a beta-secretase that is involved in the amyloidogenic pathway of amyloid precursor protein (APP), and maps to the Down syndrome critical region of chromosome 21. Alzheimer disease neuropathology is common in Down syndrome patients at relatively early ages, and it has thus been speculated that BACE2 co-overexpression with APP would promote the early neurodegenerative phenotype. However, the in vivo function of BACE2 has not yet been elucidated. The aim of the present work has been to analyse the impact of in vivo BACE2 overexpression using a transgenic mouse model. Our results suggest that BACE2 is not involved in the amyloidogenic pathway, cognitive dysfunction or cholinergic degeneration. However, TgBACE2 animals showed increased anxiety-like behaviour along with increased numbers of noradrenergic neurones in locus coeruleus, thus suggesting an unexpected role of BACE2 overexpression.
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Affiliation(s)
- G Azkona
- Genes and Disease Program, Center for Genomic Regulation (CRG), Barcelona Biomedical Research Park (PRBB), E-08003 Barcelona, Catalonia, Spain
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Functional genomic analysis of amniotic fluid cell-free mRNA suggests that oxidative stress is significant in Down syndrome fetuses. Proc Natl Acad Sci U S A 2009; 106:9425-9. [PMID: 19474297 DOI: 10.1073/pnas.0903909106] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
To characterize the differences between second trimester Down syndrome (DS) and euploid fetuses, we used Affymetrix microarrays to compare gene expression in uncultured amniotic fluid supernatant samples. Functional pathway analysis highlighted the importance of oxidative stress, ion transport, and G protein signaling in the DS fetuses. Further evidence supporting these results was derived by correlating the observed gene expression patterns to those of small molecule drugs via the Connectivity Map. Our results suggest that there are secondary adverse consequences of DS evident in the second trimester, leading to testable hypotheses about possible antenatal therapy for DS.
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Shaked GM, Chauv S, Ubhi K, Hansen LA, Masliah E. Interactions between the amyloid precursor protein C-terminal domain and G proteins mediate calcium dysregulation and amyloid beta toxicity in Alzheimer's disease. FEBS J 2009; 276:2736-51. [PMID: 19368557 DOI: 10.1111/j.1742-4658.2009.06997.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Alzheimer's disease is characterized by neuropathological accumulations of amyloid beta(1-42) [A beta(1-42)], a cleavage product of the amyloid precursor protein (APP). Recent studies have highlighted the role of APP in A beta-mediated toxicity and have implicated the G-protein system; however, the exact mechanisms underlying this pathway are as yet undetermined. In this context, we sought to investigate the role of calcium upregulation following APP-dependent, A beta-mediated G-protein activation. Initial studies on the interaction between APP, A beta and Go proteins demonstrated that the interaction between APP, specifically its C-terminal -YENPTY- region, and Go was reduced in the presence of A beta. Cell death and calcium influx in A beta-treated cells were shown to be APP dependent and to involve G-protein activation because these effects were blocked by use of the G-protein inhibitor, pertussis toxin. Collectively, these results highlight a role for the G-protein system in APP-dependent, A beta-induced toxicity and calcium dysregulation. Analysis of the APP:Go interaction in human brain samples from Alzheimer's disease patients at different stages of the disease revealed a decrease in the interaction, correlating with disease progression. Moreover, the reduced interaction between APP and Go was shown to correlate with an increase in membrane A beta levels and G-protein activity, showing for first time that the APP:Go interaction is present in humans and is responsive to A beta load. The results presented support a role for APP in A beta-induced G-protein activation and suggest a mechanism by which basal APP binding to Go is reduced under pathological loads of A beta, liberating Go and activating the G-protein system, which may in turn result in downstream effects including calcium dysregulation. These results also suggest that specific antagonists of G-protein activity may have a therapeutic relevance in Alzheimer's disease.
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Affiliation(s)
- Gideon M Shaked
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093-0624, USA
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Altafaj X, Ortiz-Abalia J, Fernández M, Potier MC, Laffaire J, Andreu N, Dierssen M, González-García C, Ceña V, Martí E, Fillat C. Increased NR2A expression and prolonged decay of NMDA-induced calcium transient in cerebellum of TgDyrk1A mice, a mouse model of Down syndrome. Neurobiol Dis 2008; 32:377-84. [PMID: 18773961 DOI: 10.1016/j.nbd.2008.07.024] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 07/24/2008] [Accepted: 07/29/2008] [Indexed: 12/16/2022] Open
Abstract
Transgenic mice overexpressing Dyrk1A (TgDyrk1A), a Down syndrome (DS) candidate gene, exhibit motor and cognitive alterations similar to those observed in DS individuals. To gain new insights into the molecular consequences of Dyrk1A overexpression underlying TgDyrk1A and possibly DS motor phenotypes, microarray studies were performed. Transcriptome analysis showed an upregulation of the NR2A subunit of the NMDA type of glutamate receptors in TgDyrk1A cerebellum. NR2A protein overexpression was also detected in TgDyrk1A cerebellar homogenates, in the synaptosome-enriched fraction and in TgDyrk1A primary cerebellar granular neuronal cultures (CGNs). In TgDyrk1A synaptosomes, calcium-imaging experiments showed a higher calcium uptake after NMDA stimulation. Similarly, NMDA administration promoted longer calcium transients in TgDyrk1A CGNs. Taken together, these results show that NMDA-induced calcium rise is altered in TgDyrk1A cerebellar neurons and indicate that calcium signaling is dysregulated in TgDyrk1A mice cerebella. These findings suggest that DYRK1A overexpression might contribute to the dysbalance in the excitatory transmission found in the cerebellum of DS individuals and DS mouse models.
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Affiliation(s)
- X Altafaj
- Programa Gens i Malatia, Centre de Regulació Genòmica-CRG, UPF, Parc de Recerca Biomèdica de Barcelona-PRBB, Barcelona, Spain
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The β1-adrenergic receptor mediates extracellular signal-regulated kinase activation via Gαs. Amino Acids 2008; 38:75-84. [DOI: 10.1007/s00726-008-0207-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Accepted: 11/03/2008] [Indexed: 01/14/2023]
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Rueda N, Flórez J, Martínez-Cué C. Effects of chronic administration of SGS-111 during adulthood and during the pre- and post-natal periods on the cognitive deficits of Ts65Dn mice, a model of Down syndrome. Behav Brain Res 2007; 188:355-67. [PMID: 18178265 DOI: 10.1016/j.bbr.2007.11.020] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Revised: 11/20/2007] [Accepted: 11/24/2007] [Indexed: 11/24/2022]
Abstract
The Ts65Dn mouse is the most commonly used model of Down syndrome. This mouse shows many phenotypic characteristics present in people with Down syndrome, including behavioral and cognitive deficits. SGS-111 is a novel analogue of the nootropic piracetam, which prevents oxidative damage and apoptosis in both normal and Down syndrome human cortical neurons. In this work we tested the ability of chronic administration of SGS-111 to adult Ts65Dn mice to reverse the cognitive deficit found in these mice. Moreover, since oxidative stress has been reported as early as the fetal stage, SGS-111 was also administered to pregnant Ts65Dn females from the day of conception throughout the pregnancy and to Ts65Dn pups during their entire life (5 months), from birth to the end of the behavioral testing period. A characterization of the effects of SGS-111 treatment on Ts65Dn and control mice sensorimotor abilities, motor coordination, spontaneous activity, activity in the open field, exploration, anxiety and spatial and non-spatial short- and long-term learning and memory was performed. The behavioral characterization showed that chronic administration of the antioxidant SGS-111 reduced the hyperactivity shown by Ts65Dn mice in their home cage, in the open field and in the hole board test. SGS-111 administration during adulthood improved performance in the first session in the Morris water maze in control mice, and when administered during the pre- and post-natal periods, improved spatial learning in the control mice but not in Ts65Dn mice. Chronic SGS-111 administration failed to affect behavior and cognition in Ts65Dn mice.
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Affiliation(s)
- Noemí Rueda
- Department of Physiology and Pharmacology, Faculty of Medicine, University of Cantabria, Santander, Spain
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