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1.
J Nanosci Nanotechnol ; 19(12): 8135-8142, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31196336

RESUMO

Precisely controlled dimensions of heterostructured ZnO nanorod arrays were grown on micropatterned Au films supported by Si substrate using chemical vapor deposition (CVD). The field emission properties were attributed to pointed nanorods, thickness of catalyst, preferential growth, density, morphology of ZnO and Molybdenum (Mo) decorated ZnO nanorod arrays (Mo/ZnO). The selective restrained heterostructure approach resulted in excellent control over periodicity, location and density of ZnO nanorod arrays. Overall, field emission properties of bare ZnO nanorod arrays showed a low turn-on field of ~4.7 V/µm and a high field enhancement factor (ß) ~1686 to 7.3 V/µm and (ß) ~807 for Mo/ZnO. It was also found that the field emission properties were significantly influenced by densely decorated Mo nanoparticles on as-grown ZnO nanorod arrays.

2.
Cell Rep ; 24(3): 713-723, 2018 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-30021167

RESUMO

Protein phosphatase 2A (PP2A) inhibition causes hyperphosphorylation of tau and APP in Alzheimer's disease (AD). However, the mechanisms underlying the downregulation of PP2A activity in AD brain remain unclear. We demonstrate that Cancerous Inhibitor of PP2A (CIP2A), an endogenous PP2A inhibitor, is overexpressed in AD brain. CIP2A-mediated PP2A inhibition drives tau/APP hyperphosphorylation and increases APP ß-cleavage and Aß production. Increase in CIP2A expression also leads to tau mislocalization to dendrites and spines and synaptic degeneration. In mice, injection of AAV-CIP2A to hippocampus induced AD-like cognitive deficits and impairments in long-term potentiation (LTP) and exacerbated AD pathologies in neurons. Indicative of disease exacerbating the feedback loop, we found that increased CIP2A expression and PP2A inhibition in AD brains result from increased Aß production. In summary, we show that CIP2A overexpression causes PP2A inhibition and AD-related cellular pathology and cognitive deficits, pointing to CIP2A as a potential target for AD therapy.


Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Autoantígenos/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Transtornos da Memória/metabolismo , Sinapses/patologia , Proteínas tau/metabolismo , Doença de Alzheimer/complicações , Doença de Alzheimer/patologia , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Células HEK293 , Hipocampo/patologia , Hipocampo/fisiopatologia , Humanos , Potenciação de Longa Duração , Transtornos da Memória/complicações , Transtornos da Memória/patologia , Camundongos Endogâmicos C57BL , Degeneração Neural/metabolismo , Degeneração Neural/patologia , Neurônios/metabolismo , Neurônios/patologia , Fosforilação , Proteína Fosfatase 2/antagonistas & inibidores , Proteína Fosfatase 2/metabolismo , Ratos Sprague-Dawley , Sinapses/metabolismo
3.
Mol Neurobiol ; 55(1): 835-850, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28064424

RESUMO

Clinical data have shown women are more susceptible to depression. This study was performed to identify differentially regulated proteins from hippocampus in chronic unpredicted mild stress (CUMS)-exposed male and female young rats. After 7 weeks of CUMS, depressed male (M-D) and female rats (F-D) and unstressed male (M-C) and female controls (F-C) were studied. By proteomics analysis, 74 differential proteins in F-C/M-C, 79 in F-D/M-D, 77 in F-D/F-C, and 32 in M-D/M-C were found. Further, the synapse-related proteins, cytoskeleton protein tau, and stress-related kinases in hippocampus were assayed by Western blotting. F-C rats were found to have lower levels of metabotropic glutamate receptor 1 (mGluR1) and mGluR2 and higher levels of N-methyl-D-aspartate receptor 2B (NR2B), synapsin1, total tau, and dephosphorylated tau than M-C rats. Both F-D and M-D rats had lower levels of glutamate transporter SLC1α2, mGluR1, and mGluR2, and higher levels of total tau and phosphorylated tau than their controls. Compared with their controls, M-D rats had lower NR1 and higher NR2B, and F-D rats had lower NR2A, NR2B, PSD95, and synapsin1. F-C rats had higher JNK and lower phosphorylation levels of ERK at Thr202/Thr204, JNK at Thr183/Thr185, and GSK-3ß at Ser9 than M-C ones. Both M-D and F-D rats had decreased phosphorylation of ERK at Thr202/Thr204 and GSK-3ß at Ser9, and increased JNK phosphorylation at Thr183/Thr185 compared with their controls. All these data illustrate the biochemical complexity behind the genders, and may also aid in the development of more accurate treatment strategies for depression.


Assuntos
Hipocampo/metabolismo , Proteômica , Caracteres Sexuais , Estresse Psicológico/metabolismo , Animais , Comportamento Animal , Doença Crônica , Citoesqueleto/metabolismo , Depressão/metabolismo , Feminino , Ontologia Genética , Masculino , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Ratos Sprague-Dawley , Sinapses/metabolismo , Proteínas tau/metabolismo
4.
Yao Xue Xue Bao ; 51(3): 434-8, 2016 03.
Artigo em Chinês | MEDLINE | ID: mdl-29859025

RESUMO

Tapentadol is a novel drug of opioid pain reliever, which is extensively metabolized primarily through conjugation. Tapentadol glucuronide and tapentadol sulfate are major drug-related metabolites in circulation. The objectives of this study were to develop a simple and rapid method to determine tapentadol and evaluate the effects of conjugated metabolites on tapentadol quantification using liquid chromatography with tandem mass spectrometry in dog plasma. The analyte and tramadol(IS) were extracted from plasma by protein precipitation with methanol, and chromatographied on a XDB C(18)(50 mm × 4.6 mm, 1.8 µm) column using a mobile phase of methanol and 5 mmol·L(-1) ammonium acetate(0.01% ammonia). Mass spectrometric detection was performed using the m/z 222 → 121 transition for tapentadol and the m/z 264 → 58 transition for the internal standard tramadol, the m/z 398 → m/z 121 transition for glucuronides conjugate and the m/z 302 → m/z 222 transition for sulfate conjugate. Conjugated metabolites could undergo in-source conversion to generate an ion that interfered the quantification of tapentadol. Chromatographic separation was achieved to elimination interferences due to in-source conversion of the conjugated metabolites. The standard curves were demonstrated to be linear in the range of 0.100 to 20.0 ng·m L(-1) for tapentadol. The intra- and inter-day precisions were within 5.1%, and accuracy ranged from -3.2% to 0. This method was successfully applied to the pharmacokinetics of tapentadol hydrochloride sustained release tablets in Beagle dogs.


Assuntos
Cães/sangue , Fenóis/sangue , Animais , Cromatografia Líquida , Preparações de Ação Retardada/farmacocinética , Glucuronídeos/sangue , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Comprimidos , Espectrometria de Massas em Tandem , Tapentadol
5.
Mol Neurobiol ; 53(3): 2054-2064, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25899174

RESUMO

Endothelin1 (ET1) is a potent vasoconstrictor that is also known to be a neuropeptide that is involved in neural circuits. We examined the role of ET1 that has been implicated in the anxiogenic process. We found that infusing ET1 into the IL cortex increased anxiety-like behaviors. The ET(A) receptor (ET(A)R) antagonist (BQ123) but not the ET(B) receptor (ET(B)R) antagonist (BQ788) alleviated ET1-induced anxiety. ET1 had no effect on GABAergic neurotransmission or NMDA receptor (NMDAR)-mediated neurotransmission, but increased AMPA receptor (AMPAR)-mediated excitatory synaptic transmission. The changes in AMPAR-mediated excitatory postsynaptic currents were due to presynaptic mechanisms. Finally, we found that the AMPAR antagonists (CNQX) and BQ123 reversed ET1's anxiogenic effect, with parallel and corresponding electrophysiological changes. Moreover, infusing CNQX + BQ123 into the IL had no additional anxiolytic effect compared to CNQX treatment alone. Altogether, our findings establish a previously unknown anxiogenic action of ET1 in the IL cortex. AMPAR-mediated glutamatergic neurotransmission may underlie the mechanism of ET1-ET(A)R signaling pathway in the regulation of anxiety.


Assuntos
Ansiedade/metabolismo , Endotelina-1/metabolismo , Sistema Límbico/metabolismo , 6-Ciano-7-nitroquinoxalina-2,3-diona/farmacologia , 6-Ciano-7-nitroquinoxalina-2,3-diona/uso terapêutico , Animais , Ansiedade/tratamento farmacológico , Comportamento Animal , Ácido Glutâmico/metabolismo , Sistema Límbico/efeitos dos fármacos , Sistema Límbico/patologia , Masculino , Camundongos Endogâmicos C57BL , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Peptídeos Cíclicos/farmacologia , Peptídeos Cíclicos/uso terapêutico , Receptores de AMPA/metabolismo , Receptores de Endotelina/metabolismo , Transmissão Sináptica/efeitos dos fármacos
6.
Neurol Sci ; 35(4): 531-6, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24057116

RESUMO

The objective of the study was to investigate the role of neuregulin-ErbB signaling in neuropathic pain in different types of injury. Neuregulin-1(NRG-1) was injected into animals with either formalin-induced pain model or spared nerve injury (SNI) model. Formalin tests or paw withdrawal tests were performed to study the role of NRG-1 in neuropathic pain. siRNA specific to different erbB receptors were then introduced to test which specific signaling pathway was required for NRG-1 signaling in the different pain models. NRG-1 inhibits neuropathic pain after SNI in a dose-dependent manner, while NRG-1 aggravates formalin-induced neuropathic pain. ErbB2 and erbB4 receptors were activated after neuregulin administration. Knockdown of ErbB2 relieves the aggravation of NRG-1 on formalin-induced neuropathic pain, and knockdown of ErbB4 could relieve the inhibition of NRG-1 on neuropathic pain in the SNI model. NRG-1 has two distinct functions depending on the different receptor activation in different models of neuropathic pain. These novel findings may provide new therapeutic approaches for the treatment of neuropathic pain in different injury types.


Assuntos
Neuralgia/metabolismo , Neuregulina-1/fisiologia , Receptor ErbB-2/metabolismo , Animais , Formaldeído , Hiperalgesia/complicações , Hiperalgesia/metabolismo , Masculino , Neuralgia/induzido quimicamente , Neuralgia/complicações , Neuregulina-1/farmacologia , Ratos
7.
Neurobiol Aging ; 34(3): 745-56, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22892311

RESUMO

The activity of protein phosphatase (PP) 2A is downregulated and promotes the hyperphosphorylation of tau in the brains of Alzheimer's disease (AD), but the mechanism for PP2A inactivation has not been elucidated. We have reported that PP2A phosphorylation at tyrosine 307 (Y307) is involved in PP2A inactivation. Here, we further studied the upstream mechanisms for PP2A phosphorylation and inactivation. We found that zinc, a heavy metal ion that is widely distributed in the normal brain and accumulated in the susceptible regions of AD brain, could induce PP2A inhibition, phosphorylation of PP2A at Y307 and tau hyperphosphorylation both in rat brains and cultured N2a cells, while zinc chelating prevented these changes completely. Upregulation of PP2A chemically or genetically attenuated zinc-induced tau hyperphosphorylation, whereas mutation of Y307 to phenylalanine abolished the zinc-induced tyrosine phosphorylation and inactivation of PP2A. Zinc could activate Src, while PP2, a specific Src family kinases inhibitor, attenuated zinc-induced PP2A phosphorylation and inactivation, indicating that zinc induces PP2A Y307 phosphorylation and inactivation through Src activation. In human tau transgenic mice, zinc chelator rescued PP2A activity, prevented Src activation, and reduced hyperphosphorylated and insoluble tau levels. We concluded that zinc induces PP2A inactivation and tau hyperphosphorylation through Src-dependent pathway, regulation of zinc homeostasis may be a promising therapeutic for AD and the related tauopathies.


Assuntos
Encéfalo , Proteína Fosfatase 2 , Tauopatias/metabolismo , Oligoelementos/farmacologia , Zinco/farmacologia , Quinases da Família src , Proteínas tau , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Linhagem Celular Tumoral , Humanos , Camundongos , Camundongos Transgênicos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Fosforilação/efeitos dos fármacos , Fosforilação/fisiologia , Proteína Fosfatase 2/efeitos dos fármacos , Proteína Fosfatase 2/metabolismo , Pirimidinas/farmacologia , Ratos , Ratos Sprague-Dawley , Tirosina/efeitos dos fármacos , Tirosina/metabolismo , Quinases da Família src/efeitos dos fármacos , Quinases da Família src/metabolismo , Proteínas tau/efeitos dos fármacos , Proteínas tau/metabolismo
8.
J Biol Chem ; 287(14): 11174-82, 2012 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-22334661

RESUMO

Hyperphosphorylated tau is the major component of neurofibrillary tangles in Alzheimer disease (AD), and the tangle distribution largely overlaps with zinc-containing glutamatergic neurons, suggesting that zinc released in synaptic terminals may play a role in tau phosphorylation. To explore this possibility, we treated cultured hippocampal slices or primary neurons with glutamate or Bic/4-AP to increase the synaptic activity with or without pretreatment of zinc chelators, and then detected the phosphorylation levels of tau. We found that glutamate or Bic/4-AP treatment caused tau hyperphosphorylation at multiple AD-related sites, including Ser-396, Ser-404, Thr-231, and Thr-205, while application of intracellular or extracellular zinc chelators, or blockade of zinc release by extracellular calcium omission almost abolished the synaptic activity-associated tau hyperphosphorylation. The zinc release and translocation of excitatory synapses in the hippocampus were detected, and zinc-induced tau hyperphosphorylation was also observed in cultured brain slices incubated with exogenously supplemented zinc. Tau hyperphosphorylation induced by synaptic activity was strongly associated with inactivation of protein phosphatase 2A (PP2A), and this inactivation can be reversed by pretreatment of zinc chelator. Together, these results suggest that synaptically released zinc promotes tau hyperphosphorylation through PP2A inhibition.


Assuntos
Inibidores Enzimáticos/farmacologia , Proteína Fosfatase 2/antagonistas & inibidores , Sinapses/efeitos dos fármacos , Sinapses/metabolismo , Zinco/metabolismo , Proteínas tau/metabolismo , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Animais , Hipocampo/citologia , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Masculino , Fosforilação/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Transmissão Sináptica/efeitos dos fármacos , Zinco/farmacologia
9.
Mol Brain ; 1: 17, 2008 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-19021916

RESUMO

α-synuclein (α-syn) is a main component of Lewy bodies (LB) that occur in many neurodegenerative diseases, including Parkinson's disease (PD), dementia with LB (DLB) and multi-system atrophy. α-syn mutations or amplifications are responsible for a subset of autosomal dominant familial PD cases, and overexpression causes neurodegeneration and motor disturbances in animals. To investigate mechanisms for α-syn accumulation and toxicity, we studied a mouse model of lysosomal enzyme cathepsin D (CD) deficiency, and found extensive accumulation of endogenous α-syn in neurons without overabundance of α-syn mRNA. In addition to impaired macroautophagy, CD deficiency reduced proteasome activity, suggesting an essential role for lysosomal CD function in regulating multiple proteolytic pathways that are important for α-syn metabolism. Conversely, CD overexpression reduces α-syn aggregation and is neuroprotective against α-syn overexpression-induced cell death in vitro. In a C. elegans model, CD deficiency exacerbates α-syn accumulation while its overexpression is protective against α-syn-induced dopaminergic neurodegeneration. Mutated CD with diminished enzymatic activity or overexpression of cathepsins B (CB) or L (CL) is not protective in the worm model, indicating a unique requirement for enzymatically active CD. Our data identify a conserved CD function in α-syn degradation and identify CD as a novel target for LB disease therapeutics.


Assuntos
Catepsina D/metabolismo , Lisossomos/enzimologia , alfa-Sinucleína/metabolismo , alfa-Sinucleína/toxicidade , Animais , Caenorhabditis elegans/efeitos dos fármacos , Caspase 3/metabolismo , Catepsina D/deficiência , Linhagem Celular Tumoral , Humanos , Lisossomos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Fármacos Neuroprotetores/metabolismo , Fagossomos/efeitos dos fármacos , Fagossomos/metabolismo , Mutação Puntual/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Estrutura Quaternária de Proteína , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genética , alfa-Sinucleína/genética
10.
Mol Neurobiol ; 32(2): 145-55, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16215279

RESUMO

Ischemic stroke, or a brain attack, is the third leading cause of death in developed countries. A critical feature of the disease is a highly selective pattern of neuronal loss; certain identifiable subsets of neurons--particularly CA1 pyramidal neurons in the hippocampus are severely damaged, whereas others remain intact. A key step in this selective neuronal injury is Ca2+/Zn2+ entry into vulnerable neurons through alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor channels, a principle subtype of glutamate receptors. AMPA receptor channels are assembled from glutamate receptor (GluR)1, -2, -3, and -4 subunits. Circumstance data have indicated that the GluR2 subunits dictate Ca2+/Zn2+ permeability of AMPA receptor channels and gate injurious Ca2+/Zn2+ signals in vulnerable neurons. Therefore, targeting to the AMPA receptor subunit GluR2 can be considered a practical strategy for stroke therapy.


Assuntos
Isquemia Encefálica/metabolismo , Isquemia Encefálica/patologia , Receptores de AMPA/metabolismo , Glutamatos/toxicidade , Humanos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Células Piramidais/efeitos dos fármacos , Células Piramidais/metabolismo , Receptores de AMPA/genética , Receptores de N-Metil-D-Aspartato/metabolismo
11.
Zhongguo Zhong Yao Za Zhi ; 30(11): 847-50, 2005 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-16110869

RESUMO

OBJECTIVE: To evaluate the effect of tea polyphenol(TP) on the rat with alcoholic liver damage. METHOD: Rats were divided into 3 groups, in which 2 groups were stomach perfused with alcohol to result in ALD, and 1 group of them stomach perfused with TP simultaneously. Another group was normal control groups (stomach perfused with drinking water). In the end of 12 weeks, the liver specimen of each rat was observed by anglicizing its tissue damage, and all data collected was performed by statistical analysis in quantum and semi-quantum. Meanwhile cytokines gene express of each group is determined. RESULT: In the end of 12 weeks, alcoholic hepatitis appeared in rat liver. Hepatic injury in alcohol group and TP group were found, but could not be found in normal group. Compared with pure alcohol group, alcoholic liver damage mainly showing with steatosis in TP group were slight, in addition showing liver cellular swelling with small area, with less spot and focal necrosis, none bridging necrosis. Steatosis were slight relatively, mega-bubble steatosis were less found. Collagen deposition of TP group were less than those of pure alcohol group. Gene expression of. cytokine have diversity statistically such as IL-3, IL-4, IL-1R2, IL-6R, IL-7R2, IL-3Ra, IL-R1, IL-13, IL-1R1, IL-7R2, EPO-R, LIFR, IL-1R2, IL-5R2, CSF1, CD27, IL-6R. CONCLUSION: TP is able to attenuate alcoholic liver damage. It's mechanism is possibly due to modulating cytokines gene expression of cytokine.


Assuntos
Flavonoides/farmacologia , Interleucinas/biossíntese , Hepatopatias Alcoólicas/metabolismo , Fenóis/farmacologia , Receptores de Interleucina/biossíntese , Chá , Animais , Flavonoides/isolamento & purificação , Expressão Gênica , Interleucinas/genética , Fígado/metabolismo , Fígado/patologia , Hepatopatias Alcoólicas/genética , Hepatopatias Alcoólicas/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Fenóis/isolamento & purificação , Plantas Medicinais/química , Polifenóis , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Receptores de Interleucina/genética , Chá/química
12.
Neuron ; 43(1): 43-55, 2004 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-15233916

RESUMO

CA1 pyramidal neurons degenerate after transient global ischemia, whereas neurons in other regions of the hippocampus remain intact. A step in this selective injury is Ca(2+) and/or Zn(2+) entry through Ca(2+)-permeable AMPA receptor channels; reducing Ca(2+) permeability of AMPA receptors via expression of Ca(2+)-impermeable GluR2(R) channels or activation of CRE transcription in the hippocampus of adult rats in vivo using shutoff-deficient pSFV-based vectors rescues vulnerable CA1 pyramidal neurons from forebrain ischemic injury. Conversely, the induction of Ca(2+) and/or Zn(2+) influx through AMPA receptors by expressing functional Ca(2+)-permeable GluR2(Q) channels causes the postischemic degeneration of hippocampal granule neurons that otherwise are insensitive to ischemic insult. Thus, the AMPA receptor subunit GluR2 gates entry of Ca(2+) and/or Zn(2+) that leads to cell death following transient forebrain ischemia.


Assuntos
Canais de Cálcio/metabolismo , Sinalização do Cálcio/genética , Ataque Isquêmico Transitório/metabolismo , Prosencéfalo/metabolismo , Receptores de AMPA/metabolismo , Animais , Animais Recém-Nascidos , Cálcio/metabolismo , Canais de Cálcio/genética , Canais de Cálcio Tipo Q/genética , Canais de Cálcio Tipo Q/metabolismo , Morte Celular/genética , Permeabilidade da Membrana Celular/genética , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Quinase 5 Dependente de Ciclina , Quinases Ciclina-Dependentes/genética , Quinases Ciclina-Dependentes/metabolismo , Modelos Animais de Doenças , Hipocampo/metabolismo , Hipocampo/fisiopatologia , Técnicas In Vitro , Integrases/genética , Integrases/metabolismo , Ativação do Canal Iônico/genética , Ataque Isquêmico Transitório/genética , Ataque Isquêmico Transitório/patologia , Degeneração Neural/genética , Degeneração Neural/metabolismo , Degeneração Neural/patologia , Prosencéfalo/patologia , Ligação Proteica/genética , Células Piramidais/metabolismo , Células Piramidais/patologia , Ratos , Ratos Sprague-Dawley , Receptores de AMPA/genética , Zinco/metabolismo
13.
Proc Natl Acad Sci U S A ; 101(25): 9453-7, 2004 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-15197280

RESUMO

New neurons are generated in adult mammalians and may contribute to repairing the brain after injury. Here, we show that the number of new neurons in the dentate gyrus of adult rats increased in cerebral ischemic stroke and correlated with activation of the cAMP-response-element-binding protein (CREB). Inhibition of endogenous CREB by expression of a dominant-negative mutant of CREB (CREB-S133A or CREB-R287L) blocked ischemia-induced neurogenesis in the dentate gyrus of adult rats, whereas expression of constitutively active CREB, VP16-CREB, increased the number of new neurons. Thus, our findings provide roles and regulatory mechanisms for CREB in adult neurogenesis and possibly suggest a practical strategy for replacing dead neurons in brain injury.


Assuntos
Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Giro Denteado/fisiopatologia , Ataque Isquêmico Transitório/fisiopatologia , Regeneração Nervosa/fisiologia , Neurônios/fisiologia , Animais , Feminino , Imuno-Histoquímica , Masculino , Mutagênese , Mutagênese Sítio-Dirigida , Ratos , Proteínas Recombinantes/metabolismo , Caracteres Sexuais
14.
Nat Neurosci ; 6(10): 1039-47, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-14502288

RESUMO

CA1 pyramidal neurons degenerate after transient forebrain ischemia, whereas neurons in other regions of the hippocampus remain intact. Here we show that in rat hippocampal CA1 neurons, forebrain ischemia induces the phosphorylation of the N-methyl-D-aspartate (NMDA) receptor 2A subunit at Ser1232 (phospho-Ser1232). Ser1232 phosphorylation is catalyzed by cyclin-dependent kinase 5 (Cdk5). Inhibiting endogenous Cdk5, or perturbing interactions between Cdk5 and NR2A subunits, abolished NR2A phosphorylation at Ser1232 and protected CA1 pyramidal neurons from ischemic insult. Thus, we conclude that modulation of NMDA receptors by Cdk5 is the primary intracellular event underlying the ischemic injury of CA1 pyramidal neurons.


Assuntos
Isquemia Encefálica/enzimologia , Quinases Ciclina-Dependentes/metabolismo , Hipocampo/enzimologia , Células Piramidais/enzimologia , Receptores de N-Metil-D-Aspartato/metabolismo , Sequência de Aminoácidos/fisiologia , Animais , Isquemia Encefálica/patologia , Isquemia Encefálica/fisiopatologia , Morte Celular/fisiologia , Quinase 5 Dependente de Ciclina , Quinases Ciclina-Dependentes/genética , Antagonistas de Aminoácidos Excitatórios/farmacologia , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Potenciais Pós-Sinápticos Excitadores/fisiologia , Vetores Genéticos/farmacologia , Hipocampo/patologia , Hipocampo/fisiopatologia , Mutação/genética , Degeneração Neural/enzimologia , Degeneração Neural/etiologia , Degeneração Neural/fisiopatologia , Técnicas de Cultura de Órgãos , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Fosforilação , Células Piramidais/patologia , Ratos , Ratos Sprague-Dawley , Receptores de N-Metil-D-Aspartato/genética , Proteínas Recombinantes de Fusão/farmacologia , Traumatismo por Reperfusão/enzimologia , Traumatismo por Reperfusão/patologia , Traumatismo por Reperfusão/fisiopatologia , Serina/metabolismo
15.
J Neurosci ; 23(3): 732-6, 2003 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-12574400

RESUMO

Several thousand new neurons are produced each day in the adult mammalian hippocampus, among which only excitatory granule cells (GCs) have thus far been identified. In the present study, we used mutant Semliki Forest Virus vectors to express enhanced green fluorescent protein in the hippocampus, and observed that approximately 14% of newly generated neurons in the dentate gyrus of adult rats are GABAergic basket cells (BCs). With the use of double whole-cell patch-clamp recordings from BC-GC pairs in hippocampal slices, we demonstrate that newly generated BCs in the dentate gyrus form inhibitory synapses with principal GCs. These data show for the first time that functional inhibitory neurons are recruited in the dentate gyrus of adult rats.


Assuntos
Hipocampo/citologia , Inibição Neural/fisiologia , Neurônios/citologia , Animais , Bromodesoxiuridina , Contagem de Células , Diferenciação Celular/fisiologia , Divisão Celular/fisiologia , Potenciais Pós-Sinápticos Excitadores/fisiologia , Feminino , Genes Reporter , Vetores Genéticos/administração & dosagem , Vetores Genéticos/fisiologia , Glutamato Descarboxilase/análise , Glutamato Descarboxilase/biossíntese , Proteínas de Fluorescência Verde , Hipocampo/crescimento & desenvolvimento , Hipocampo/virologia , Imuno-Histoquímica , Isoenzimas/análise , Isoenzimas/biossíntese , Proteínas Luminescentes/genética , Masculino , Neurônios/classificação , Neurônios/metabolismo , Neurônios/virologia , Técnicas de Patch-Clamp , Fenótipo , Ratos , Ratos Sprague-Dawley , Vírus da Floresta de Semliki/genética , Vírus da Floresta de Semliki/fisiologia , Transmissão Sináptica/fisiologia , Ácido gama-Aminobutírico/metabolismo
16.
J Neurosci ; 23(3): 826-36, 2003 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-12574411

RESUMO

Long-term depression (LTD) is an activity-dependent weakening of synaptic efficacy at individual inhibitory synapses, a possible cellular model of learning and memory. Here, we show that the induction of LTD of inhibitory transmission recruits activated calcineurin (CaN) to dephosphorylate type-A GABA receptor (GABA(A)Rs) via the direct binding of CaN catalytic domain to the second intracellular domain of the GABA(A)R-gamma(2) subunits. Prevention of the CaN-GABA(A) receptor complex formation by expression of an autoinhibitory domain of CaN in the hippocampus of transgenic mice blocks the induction of LTD. Conversely, genetic expression of the CaN catalytic domain in the hippocampus depresses inhibitory synaptic responses, occluding LTD. Thus, an activity-dependent physical and functional interaction between CaN and GABA(A) receptors is both necessary and sufficient for inducing LTD at CA1 individual inhibitory synapses.


Assuntos
Calcineurina/metabolismo , Hipocampo/metabolismo , Depressão Sináptica de Longo Prazo/fisiologia , Inibição Neural/fisiologia , Receptores de GABA-A/metabolismo , Sinapses/metabolismo , Animais , Estimulação Elétrica , Hipocampo/citologia , Técnicas In Vitro , Substâncias Macromoleculares , Camundongos , Camundongos Mutantes , Camundongos Transgênicos , Técnicas de Patch-Clamp , Fosforilação , Ligação Proteica/fisiologia , Subunidades Proteicas/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo
17.
J Neurosci ; 23(1): 223-9, 2003 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-12514219

RESUMO

The generation of new neurons in the adult mammalian hippocampus is thought to play a role in repairing the brain after injury. Here, we show that 7 d after focal cerebral ischemia, newly divided cells in the dentate gyrus of adult rats increased to approximately sevenfold, compared with sham controls. In the same area, this enhanced dentate neurogenesis was associated with activation of inducible nitric oxide synthase (iNOS). Inhibition of iNOS by aminoguanidine prevented ischemia-induced neurogenesis in the dentate gyrus. In null mutant mice lacking the iNOS gene, increased neurogenesis was not observed after focal cerebral ischemia. This study demonstrates that expression of iNOS is necessary for ischemia-stimulated cell birth in the dentate gyrus and indicates that activation of iNOS may provide a possible strategy for functional recovery from cerebral ischemic insult.


Assuntos
Isquemia Encefálica/enzimologia , Giro Denteado/citologia , Giro Denteado/enzimologia , Neurônios/citologia , Óxido Nítrico Sintase/fisiologia , Animais , Arginina/farmacologia , Isquemia Encefálica/genética , Isquemia Encefálica/patologia , Divisão Celular , Inibidores Enzimáticos/farmacologia , Deleção de Genes , Proteínas de Fluorescência Verde , Cinética , Proteínas Luminescentes/análise , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neuroglia/citologia , Neurônios/enzimologia , Óxido Nítrico Sintase/biossíntese , Óxido Nítrico Sintase/genética , Óxido Nítrico Sintase Tipo II , RNA Mensageiro/biossíntese , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transcrição Genética
18.
EMBO J ; 21(12): 2977-89, 2002 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-12065411

RESUMO

Src kinase regulation of N-methyl-D-aspartate (NMDA) subtype glutamate receptors in the central nervous system (CNS) has been found to play an important role in processes related to learning and memory, ethanol sensitivity and epilepsy. However, little is known regarding the mechanisms underlying the regulation of Src family kinase activity in the control of NMDA receptors. Here we report that the distal phosphatase domain (D2) of protein tyrosine phosphatase alpha (PTPalpha) binds to the PDZ2 domain of post-synaptic density 95 (PSD95). Thus, Src kinase, its activator (PTPalpha) and substrate (NMDA receptors) are linked by the same scaffold protein, PSD95. Removal of PTPalpha does not affect the association of Src with NMDA receptors, but turns off the constitutive regulation of NMDA receptors by the kinase. Further more, we found that application of the PTPalpha catalytic domains (D1 + D2) into neurones enhances NMDA receptor-mediated synaptic responses. Conversely, the blockade of endogenous PTPalpha inhibits NMDA receptor activity and the induction of long-term potentiation in hippocampal neurones. Thus, PTPalpha is a novel up-regulator of synaptic strength in the CNS.


Assuntos
Neurônios/metabolismo , Estrutura Secundária de Proteína , Proteínas Tirosina Fosfatases/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Transmissão Sináptica/fisiologia , Animais , Células Cultivadas , Proteína 4 Homóloga a Disks-Large , Fibroblastos/fisiologia , Hipocampo/citologia , Humanos , Técnicas In Vitro , Peptídeos e Proteínas de Sinalização Intracelular , Potenciação de Longa Duração/fisiologia , Proteínas de Membrana , Modelos Biológicos , Proteínas do Tecido Nervoso/metabolismo , Neurônios/citologia , Neurônios/efeitos dos fármacos , Técnicas de Patch-Clamp , Ligação Proteica , Proteínas Tirosina Fosfatases/genética , Proteínas Tirosina Fosfatases/farmacologia , Ratos , Ratos Sprague-Dawley , Ratos Wistar , Receptores de N-Metil-D-Aspartato/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Quinases da Família src/metabolismo
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