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1.
Genes Cells ; 26(11): 861-873, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34387016

RESUMO

Intracellular amyloid-ß (Aß) oligomers are key therapeutic targets because they are strongly cytotoxic and play crucial roles in the cognitive function in Alzheimer's disease (AD). Anthocyanins, polyphenolic flavonoids with antioxidant and neuroprotective properties, are potential therapeutic candidates for AD. Here, we investigated the effects of anthocyanin-enriched extracts from fruits of mulberry (Morus alba Linn.) in Thailand against the neurotoxicity of Aß oligomers. Using the monitoring system for Aß aggregation, we showed that the extract induced the dissociation of Aß in cultured HEK293T cells. To investigate the effects on cognitive function, we orally administered the extract to Aß-GFP transgenic mice (Aß-GFP Tg), a mouse model that expresses Aß oligomers inside neurons, and performed the novel object recognition test and passive avoidance test. Aß-GFP Tg usually showed deficits in novel object recognition memory and reference memory compared with non-Tg, but administration of the extract improved both compared with vehicle-treated Aß-GFP Tg. Aß-GFP Tg exhibited lower superoxide dismutase (SOD) activity than non-Tg. However, after the administration of the extract, the SOD activity was restored. These results suggest that Thai mulberry fruit extract ameliorates cytotoxicity induced by the intracellular Aß oligomers and may be an effective therapeutic or preventive candidate for AD.


Assuntos
Doença de Alzheimer , Morus , Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/metabolismo , Peptídeos beta-Amiloides/toxicidade , Animais , Antocianinas , Cognição , Modelos Animais de Doenças , Frutas/metabolismo , Células HEK293 , Humanos , Camundongos , Camundongos Transgênicos , Morus/metabolismo , Estresse Oxidativo , Extratos Vegetais/farmacologia
2.
Genes Cells ; 21(2): 200-11, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26805741

RESUMO

The occurrence of senile plaques consisting of amyloid-ß protein (Aß) is a major neuropathological hallmark of Alzheimer's disease (AD). We previously developed and characterized monoclonal antibodies 31-2 and 75-2 that specifically bind to nonfibrillar Aß1-42 aggregates with diameters of more than 220 and 50 nm, respectively. Here, we report the use of these antibodies to examine the aggregation of exogenous Aß1-42 in cultured rat hippocampal neurons. From 6 to 24 h after transfection of Aß1-42, antibody 75-2 immunolabeled almost all transfected neurons, whereas 31-2-positive cells were restricted to a part of the transfected neurons and gradually increased in number. Expression of the F19S/L34P-mutant Aß1-42, which showed less of a tendency to aggregate, resulted in clearly reduced immunoreactivity to both antibodies. We also immunohistochemically investigated the temporal cortices of patients with AD and found that 31-2 preferentially labeled the cores of a subpopulation of large amyloid plaques. The relative number of 31-2-immunoreactive plaques was found to correlate with the Braak stages of neurofibrillary tangles, but not with that of amyloid plaques. These results suggest that 31-2-reactive Aß aggregates develop with a delayed time course in cultured neurons and amyloid plaques of AD brains.


Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/imunologia , Anticorpos Monoclonais/metabolismo , Hipocampo/citologia , Neurônios/metabolismo , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/genética , Animais , Células Cultivadas , Feminino , Hipocampo/metabolismo , Humanos , Imuno-Histoquímica , Masculino , Mutação , Neurônios/citologia , Ratos , Ratos Wistar
3.
Exp Anim ; 2023 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-38092387

RESUMO

Disturbances in sleep-wake and circadian rhythms may reportedly precede the onset of cognitive symptoms in the early stages of Alzheimer's disease (AD); however, the underlying mechanisms of these AD-induced sleep disturbances remain unelucidated. To specifically evaluate the involvement of amyloid ß (Aß) oligomers in AD-induced sleep disturbances, we examined circadian and sleep phenotypes using an Aß-GFP transgenic (Aß-GFP Tg) mouse characterized by intracellular accumulation of Aß oligomers. The circadian rhythm and free-running period of wheel running activity were identical between Aß-GFP Tg and littermate wild-type mice. The durations of rapid eye movement (REM) sleep were elongated in Aß-GFP Tg mice; however, the durations of non-REM sleep and wakefulness were unaffected. The Aß-GFP Tg mice exhibited shifts in the electroencephalogram (EEG) power spectra toward higher frequencies in the inactive light phase. These findings suggest that the intracellular accumulation of Aß oligomers might be associated with sleep quality; however, its impact on circadian systems is limited.

4.
Trends Cell Biol ; 15(3): 172-8, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15752981

RESUMO

Delta-catenin belongs to the p120-catenin (p120(ctn)) protein family, which is characterized by ten, characteristically spaced Armadillo repeats that bind to the juxtamembrane segment of the classical cadherins. Delta-catenin is the only member of this family that is expressed specifically in neurons, where it binds to PDZ domain proteins in the post-synaptic compartment. As a component of both adherens and synaptic junctions, delta-catenin can link the adherens junction to the synapse and, thereby, coordinate synaptic input with changes in the adherens junction. By virtue of its restriction to the post-synaptic area, delta-catenin creates an asymmetric adherens junction in the region of the synapse. The crucial nature of the specialized function of delta-catenin in neurons is demonstrated by a targeted gene mutation, which causes deficits in learning and in synaptic plasticity. Taken together, recent evidence indicates that delta-catenin is a sensor of synaptic activity and implements activity-related morphological changes at the synapse.


Assuntos
Junções Aderentes/química , Proteínas do Citoesqueleto/fisiologia , Sinapses/metabolismo , Animais , Proteínas do Domínio Armadillo , Caderinas/metabolismo , Cateninas , Moléculas de Adesão Celular , Drosophila melanogaster , Humanos , Modelos Biológicos , Modelos Neurológicos , Mutação , Proteínas do Tecido Nervoso/química , Neurônios/metabolismo , Fosfoproteínas , Estrutura Terciária de Proteína , delta Catenina
5.
J Cell Biol ; 162(1): 99-111, 2003 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-12835311

RESUMO

Delta-catenin is a neuronal protein that contains 10 Armadillo motifs and binds to the juxtamembrane segment of classical cadherins. We report that delta-catenin interacts with cortactin in a tyrosine phosphorylation-dependent manner. This interaction occurs within a region of the delta-catenin sequence that is also essential for the neurite elongation effects. Src family kinases can phosphorylate delta-catenin and bind to delta-catenin through its polyproline tract. Under conditions when tyrosine phosphorylation is reduced, delta-catenin binds to cortactin and cells extend unbranched primary processes. Conversely, increasing tyrosine phosphorylation disrupts the delta-catenin-cortactin complex. When RhoA is inhibited, delta-catenin enhances the effects of Rho inhibition on branching. We conclude that delta-catenin contributes to setting a balance between neurite elongation and branching in the elaboration of a complex dendritic tree.


Assuntos
Encéfalo/embriologia , Diferenciação Celular/fisiologia , Proteínas do Citoesqueleto/metabolismo , Proteínas dos Microfilamentos/metabolismo , Neuritos/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo , Sequência de Aminoácidos/fisiologia , Animais , Proteínas do Domínio Armadillo , Encéfalo/citologia , Encéfalo/metabolismo , Cateninas , Moléculas de Adesão Celular , Tamanho Celular/fisiologia , Cortactina , Proteínas do Citoesqueleto/genética , Dendritos/metabolismo , Dendritos/ultraestrutura , Feto , Vetores Genéticos/genética , Proteínas dos Microfilamentos/genética , Neuritos/ultraestrutura , Células PC12 , Fosfoproteínas , Fosforilação , Prolina/metabolismo , Ligação Proteica/fisiologia , Estrutura Terciária de Proteína/fisiologia , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes de Fusão , Tirosina/metabolismo , Proteína rhoA de Ligação ao GTP/antagonistas & inibidores , Proteína rhoA de Ligação ao GTP/genética , Quinases da Família src/genética , Quinases da Família src/metabolismo , delta Catenina
6.
Mol Cell Neurosci ; 39(4): 499-507, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18602475

RESUMO

delta-catenin is a protein that binds to the classical cadherins and to synaptic scaffolding proteins in a manner which allows the protein to serve as a link between the adherens junction and the postsynaptic complex. Here we show the regulatory role of delta-catenin on synaptic transmission. delta-catenin increased the AMPA receptor-mediated EPSC, but had no significant effect on the NMDA receptor-mediated EPSC. The effect of delta-catenin on the AMPAR EPSC was mediated by its PDZ ligand. delta-catenin regulates the surface expression of GluR2 in the dendritic spines of neurons. Immunoprecipitation revealed that delta-catenin bound to GRIP-1. In COS7 cells, co-transfection of delta-catenin, GRIP and GluR2 showed that delta-catenin regulates the membrane localization of GRIP through its PDZ ligand and increased the surface expression of GluR2. This study directly shows that delta-catenin is essential for the trafficking and positioning GluR2 in the spine and thus further links delta-catenin to neuronal plasticity.


Assuntos
Moléculas de Adesão Celular/metabolismo , Fosfoproteínas/metabolismo , Receptores de AMPA/metabolismo , Transmissão Sináptica/fisiologia , Animais , Células COS , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Cateninas , Moléculas de Adesão Celular/genética , Células Cultivadas , Chlorocebus aethiops , Potenciais Pós-Sinápticos Excitadores/fisiologia , Hipocampo/citologia , Peptídeos e Proteínas de Sinalização Intracelular , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Plasticidade Neuronal/fisiologia , Neurônios/citologia , Neurônios/metabolismo , Técnicas de Patch-Clamp , Fosfoproteínas/genética , Interferência de RNA , Ratos , Ratos Sprague-Dawley , Receptores de AMPA/genética , Receptores de N-Metil-D-Aspartato/genética , Receptores de N-Metil-D-Aspartato/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , delta Catenina
7.
Sci Rep ; 9(1): 17368, 2019 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-31757975

RESUMO

Oligomers of intracellular amyloid ß protein (Aß) are strongly cytotoxic and play crucial roles in synaptic transmission and cognitive function in Alzheimer's disease (AD). However, there is currently no AD model mouse in which to specifically analyze the function of Aß oligomers only. We have now developed a novel AD model mouse, an Aß-GFP transgenic mouse (Aß-GFP Tg), that expresses the GFP-fused human Aß1-42 protein, which forms only Aß oligomers within neurons throughout their life. The fusion proteins are expressed mainly in the hippocampal CA1-CA2 region and cerebral cortex, and are not secreted extracellularly. The Aß-GFP Tg mice exhibit increased tau phosphorylation, altered spine morphology, decreased expressions of the GluN2B receptor and neuroligin in synaptic regions, attenuated hippocampal long-term potentiation, and impaired object recognition memory compared with non-Tg littermates. Interestingly, these dysfunctions have already appeared in 2-3-months-old animals. The Aß-GFP fusion protein is bioactive and highly toxic, and induces the similar synaptic dysfunctions as the naturally generated Aß oligomer derived from postmortem AD patient brains and synthetic Aß oligomers. Thus, Aß-GFP Tg mouse is a new tool specialized to analyze the function of Aß oligomers in vivo and to find subtle changes in synapses in early symptoms of AD.


Assuntos
Doença de Alzheimer/patologia , Peptídeos beta-Amiloides , Modelos Animais de Doenças , Camundongos Transgênicos , Neurônios/metabolismo , Doença de Alzheimer/genética , Peptídeos beta-Amiloides/genética , Peptídeos beta-Amiloides/metabolismo , Peptídeos beta-Amiloides/toxicidade , Animais , Citotoxinas/metabolismo , Proteínas de Fluorescência Verde/genética , Hipocampo/metabolismo , Hipocampo/patologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Neurônios/patologia , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/metabolismo , Agregação Patológica de Proteínas/patologia , Multimerização Proteica/genética , Proteínas Recombinantes de Fusão/genética , Sinapses/metabolismo , Sinapses/patologia , Sinapses/fisiologia
8.
Neurosci Lett ; 426(3): 149-54, 2007 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-17897781

RESUMO

Addicsin is a member of the prenylated Rab acceptor (PRA) 1 domain family and a murine homolog of the rat glutamate-transporter-associated protein 3-18 (GTRAP3-18). This protein is considered to function as a modulator of the neural glutamate transporter excitatory amino acid carrier 1 (EAAC1). However, its molecular functions remain largely unknown. Here, we examined the regional and cellular localization of addicsin in the central nervous system (CNS) by using a newly generated antibody specific for the protein. Distribution analysis by Western blot and immunohistochemistry demonstrated that the protein was widely distributed in various regions of the mature CNS, including the olfactory bulbs, cerebral cortex, amygdala, hippocampus CA1-3 fields, dentate gyrus, and cerebellum. Double immunofluorescence analysis revealed that addicsin was expressed in the somata of principal neurons in the CNS such as the pyramidal cells and gamma-aminobutyric acid (GABA)-ergic interneurons scattered in the hippocampal formation. Furthermore, the protein showed pre-synaptic localization in the stratum lucidum of the CA3 field of the hippocampal formation. Subcellular localization analysis of highly purified synaptic fractions prepared from mouse forebrain supported the cytoplasmic and pre-synaptic distribution of addicsin. These results suggest that addicsin has neural expression and may play crucial roles in the basic physiological functions of the mature CNS.


Assuntos
Encéfalo/metabolismo , Proteínas de Transporte/metabolismo , Neurônios/metabolismo , Animais , Western Blotting , Imunofluorescência , Expressão Gênica , Perfilação da Expressão Gênica , Proteínas de Choque Térmico , Proteínas de Membrana Transportadoras , Camundongos , Sinapses/metabolismo
9.
Sci Rep ; 6: 22712, 2016 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-26982553

RESUMO

The intracellular accumulation of amyloid-ß (Aß) oligomers critically contributes to disease progression in Alzheimer's disease (AD) and can be the potential target of AD therapy. Direct observation of molecular dynamics of Aß oligomers in vivo is key for drug discovery research, however, it has been challenging because Aß aggregation inhibits the fluorescence from fusion proteins. Here, we developed Aß1-42-GFP fusion proteins that are oligomerized and visualize their dynamics inside cells even when aggregated. We examined the aggregation states of Aß-GFP fusion proteins using several methods and confirmed that they did not assemble into fibrils, but instead formed oligomers in vitro and in live cells. By arranging the length of the liker between Aß and GFP, we generated two fusion proteins with "a long-linker" and "a short-linker", and revealed that the aggregation property of fusion proteins can be evaluated by measuring fluorescence intensities using rat primary culture neurons transfected with Aß-GFP plasmids and Aß-GFP transgenic C. elegans. We found that Aß-GFP fusion proteins induced cell death in COS7 cells. These results suggested that novel Aß-GFP fusion proteins could be utilized for studying the physiological functions of Aß oligomers in living cells and animals, and for drug screening by analyzing Aß toxicity.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Proteínas de Fluorescência Verde/metabolismo , Fragmentos de Peptídeos/metabolismo , Peptídeos beta-Amiloides/genética , Animais , Animais Geneticamente Modificados/genética , Animais Geneticamente Modificados/metabolismo , Apoptose , Células COS , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Células Cultivadas , Chlorocebus aethiops , Proteínas de Fluorescência Verde/genética , Imuno-Histoquímica , Microscopia Eletrônica , Microscopia de Fluorescência , Neurônios/citologia , Neurônios/metabolismo , Ressonância Magnética Nuclear Biomolecular , Fragmentos de Peptídeos/genética , Plasmídeos/genética , Plasmídeos/metabolismo , Multimerização Proteica , Ratos , Ratos Wistar , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/isolamento & purificação
10.
J Biol Chem ; 283(47): 32781-91, 2008 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-18809680

RESUMO

Delta-catenin is a synaptic adherens junction protein pivotally positioned to serve as a signaling sensor and integrator. Expression of delta-catenin induces filopodia-like protrusions in neurons. Here we show that the small GTPases of the Rho family act coordinately as downstream effectors of delta-catenin. A dominant negative Rac prevented delta-catenin-induced protrusions, and Cdc42 activity was dramatically increased by delta-catenin expression. A kinase dead LIMK (LIM kinase) and a mutant Cofilin also prevented delta-catenin-induced protrusions. To link the effects of delta-catenin to a physiological pathway, we noted that (S)-3,5-dihydroxyphenylglycine (DHPG) activation of metabotropic glutamate receptors induced dendritic protrusions that are very similar to those induced by delta-catenin. Furthermore, delta-catenin RNA-mediated interference can block the induction of dendritic protrusions by DHPG. Interestingly, DHPG dissociated PSD-95 and N-cadherin from the delta-catenin complex, increased the association of delta-catenin with Cortactin, and induced the phosphorylation of delta-catenin within the sites that bind to these protein partners.


Assuntos
Moléculas de Adesão Celular/fisiologia , Dendritos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Fosfoproteínas/fisiologia , Transdução de Sinais , Proteína cdc42 de Ligação ao GTP/metabolismo , Animais , Caderinas/química , Cateninas , Moléculas de Adesão Celular/metabolismo , Proteína 4 Homóloga a Disks-Large , Peptídeos e Proteínas de Sinalização Intracelular/química , Proteínas de Membrana/química , Modelos Biológicos , Mutação , Neurônios/metabolismo , Fosfoproteínas/metabolismo , Fosforilação , Ratos , Ratos Sprague-Dawley , Receptores de Glutamato/metabolismo , delta Catenina
11.
Hippocampus ; 12(6): 821-33, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12542233

RESUMO

Transcriptional profiling (TP) offers a powerful approach to identify genes activated during memory formation and, by inference, the molecular pathways involved. Trace eyeblink conditioning is well suited for the study of regional gene expression because it requires the hippocampus, whereas the highly parallel task, delay conditioning, does not. First, we determined when gene expression was most regulated during trace conditioning. Rats were exposed to 200 trials per day of paired and unpaired stimuli each day for 4 days. Changes in gene expression were most apparent 24 h after exposure to 200 trials. Therefore, we profiled gene expression in the hippocampus 24 h after 200 trials of trace eyeblink conditioning, on multiple arrays using additional animals. Of 1,186 genes on the filter array, seven genes met the statistical criteria and were also validated by real-time polymerase chain reaction. These genes were growth hormone (GH), c-kit receptor tyrosine kinase (c-kit), glutamate receptor, metabotropic 5 (mGluR5), nerve growth factor-beta (NGF-beta), Jun oncogene (c-Jun), transmembrane receptor Unc5H1 (UNC5H1), and transmembrane receptor Unc5H2 (UNC5H2). All these genes, except for GH, were downregulated in response to trace conditioning. GH was upregulated; therefore, we also validated the downregulation of the GH inhibitor, somatostatin (SST), even though it just failed to meet criteria on the arrays. By during situ hybridization, GH was expressed throughout the cell layers of the hippocampus in response to trace conditioning. None of the genes regulated in trace eyeblink conditioning were similarly affected by delay conditioning, a task that does not require the hippocampus. These findings demonstrate that transcriptional profiling can exhibit a repertoire of genes sensitive to the formation of hippocampal-dependent associative memories.


Assuntos
Perfilação da Expressão Gênica , Regulação da Expressão Gênica/genética , Hipocampo/metabolismo , Memória/fisiologia , Proteínas do Tecido Nervoso/metabolismo , Neurônios/metabolismo , Transcrição Gênica/genética , Animais , Condicionamento Palpebral/fisiologia , DNA Complementar/análise , DNA Complementar/genética , Hormônio do Crescimento/genética , Masculino , Fator de Crescimento Neural/genética , Proteínas do Tecido Nervoso/genética , Receptores de Netrina , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas Proto-Oncogênicas c-jun/genética , Proteínas Proto-Oncogênicas c-kit/genética , Ratos , Ratos Sprague-Dawley , Receptor de Glutamato Metabotrópico 5 , Receptores de Superfície Celular/genética , Receptores de Glutamato Metabotrópico/genética
12.
Am J Pathol ; 160(5): 1655-67, 2002 May.
Artigo em Inglês | MEDLINE | ID: mdl-12000718

RESUMO

Mutations in alpha-synuclein (alpha S) and parkin cause heritable forms of Parkinson disease (PD). We hypothesized that neuronal parkin, a known E3 ubiquitin ligase, facilitates the formation of Lewy bodies (LBs), a pathological hallmark of PD. Here, we report that affinity-purified parkin antibodies labeled classical LBs in substantia nigra sections from four related human disorders: sporadic PD, inherited alphaS-linked PD, dementia with LBs (DLB), and LB-positive, parkin-linked PD. Anti-parkin antibodies also detected LBs in entorhinal and cingulate cortices from DLB brain and alphaS inclusions in sympathetic gangliocytes from sporadic PD. Double labeling with confocal microscopy of DLB midbrain sections revealed that approximately 90% of anti-alpha S-reactive LBs were also detected by a parkin antibody to amino acids 342 to 353. Accordingly, parkin proteins, including the 53-kd mature isoform, were present in affinity-isolated LBs from DLB cortex. Fluorescence resonance energy transfer and immunoelectron microscopy showed that alphaS and parkin co-localized within brainstem and cortical LBs. Biochemically, parkin appeared most enriched in cytosolic and postsynaptic fractions of adult rat brain, but also in purified, alpha S-rich presynaptic elements that additionally contained parkin's E2-binding partner, UbcH7. We conclude that parkin and UbcH7 are present with alphaS in subcellular compartments of normal brain and that parkin frequently co-localizes with alpha S aggregates in the characteristic LB inclusions of PD and DLB. These results suggest that functional parkin proteins may be required during LB formation.


Assuntos
Corpos de Lewy/patologia , Doença por Corpos de Lewy/patologia , Ligases/análise , Doença de Parkinson/patologia , Ubiquitina-Proteína Ligases , Sequência de Aminoácidos , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Células COS , Linhagem Celular , Humanos , Imuno-Histoquímica , Corpos de Lewy/química , Corpos de Lewy/ultraestrutura , Doença por Corpos de Lewy/metabolismo , Ligases/genética , Ligases/imunologia , Microscopia Confocal , Microscopia Eletrônica , Dados de Sequência Molecular , Mutação , Doença de Parkinson/metabolismo , Ratos , Ratos Sprague-Dawley , Células Tumorais Cultivadas
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