Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
Filtros adicionais











Tipo de estudo
Intervalo de ano
1.
Sci Rep ; 7(1): 14972, 2017 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-29097807

RESUMO

TDP-43 is an RNA-binding protein important for many aspects of RNA metabolism. Abnormal accumulation of TDP-43 in the cytoplasm of affected neurons is a pathological hallmark of the neurodegenerative diseases frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Several transgenic mouse models have been generated that recapitulate defects in TDP-43 accumulation, thus causing neurodegeneration and behavioural impairments. While aging is the key risk factor for neurodegenerative diseases, the specific effect of aging on phenotypes in TDP-43 transgenic mice has not been investigated. Here, we analyse age-dependent changes in TDP-43 transgenic mice that displayed impaired memory. We found the accumulation of abundant poly-ubiquitinated protein aggregates in the hippocampus of aged TDP-43 transgenic mice. Intriguingly, the aggregates contained some interneuron-specific proteins such as parvalbumin and calretinin, suggesting that GABAergic interneurons were degenerated in these mice. The abundance of aggregates significantly increased with age and with the overexpression of TDP-43. Gene array analyses in the hippocampus and other brain areas revealed dysregulation in genes linked to oxidative stress and neuronal function in TDP-43 transgenic mice. Our results indicate that the interneuron degeneration occurs upon aging, and TDP-43 accelerates age-dependent neuronal degeneration, which may be related to the impaired memory of TDP-43 transgenic mice.

2.
PLoS One ; 12(3): e0173175, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28264072

RESUMO

Very-KIND/Kndc1/KIAA1768 (v-KIND) is a brain-specific Ras guanine nucleotide exchange factor carrying two sets of the kinase non-catalytic C-lobe domain (KIND), and is predominantly expressed in cerebellar granule cells. Here, we report the impact of v-KIND deficiency on dendritic and synaptic growth in cerebellar granule cells in v-KIND knockout (KO) mice. Furthermore, we evaluate motor function in these animals. The gross anatomy of the cerebellum, including the cerebellar lobules, layered cerebellar cortex and densely-packed granule cell layer, in KO mice appeared normal, and was similar to wild-type (WT) mice. However, KO mice displayed an overgrowth of cerebellar granule cell dendrites, compared with WT mice, resulting in an increased number of dendrites, dendritic branches and terminals. Immunoreactivity for vGluT2 (a marker for excitatory presynapses of mossy fiber terminals) was increased in the cerebellar glomeruli of KO mice, compared with WT mice. The postsynaptic density around the terminals of mossy fibers was also increased in KO mice. Although there were no significant differences in locomotor ability between KO and WT animals in their home cages or in the open field, young adult KO mice had an increased grip strength and a tendency to exhibit better motor performance in balance-related tests compared with WT animals. Taken together, our results suggest that v-KIND is required for compact dendritic growth and proper excitatory synaptic connections in cerebellar granule cells, which are necessary for normal motor coordination and balance.


Assuntos
Encéfalo/metabolismo , Cerebelo/citologia , Cerebelo/metabolismo , Dendritos/metabolismo , Fatores de Troca do Nucleotídeo Guanina/genética , Proteínas do Tecido Nervoso/genética , Desempenho Psicomotor , Animais , Axônios/metabolismo , Biomarcadores , Potenciais Pós-Sinápticos Excitadores , Fatores de Troca do Nucleotídeo Guanina/química , Imuno-Histoquímica , Camundongos , Camundongos Knockout , Proteínas do Tecido Nervoso/química , Especificidade de Órgãos/genética , Sinapses/metabolismo , Sinapses/ultraestrutura
3.
EMBO Mol Med ; 5(2): 221-34, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23255347

RESUMO

Two motor neuron diseases, amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA), are caused by distinct genes involved in RNA metabolism, TDP-43 and FUS/TLS, and SMN, respectively. However, whether there is a shared defective mechanism in RNA metabolism common to these two diseases remains unclear. Here, we show that TDP-43 and FUS/TLS localize in nuclear Gems through an association with SMN, and that all three proteins function in spliceosome maintenance. We also show that in ALS, Gems are lost, U snRNA levels are up-regulated and spliceosomal U snRNPs abnormally and extensively accumulate in motor neuron nuclei, but not in the temporal lobe of FTLD with TDP-43 pathology. This aberrant accumulation of U snRNAs in ALS motor neurons is in direct contrast to SMA motor neurons, which show reduced amounts of U snRNAs, while both have defects in the spliceosome. These findings indicate that a profound loss of spliceosome integrity is a critical mechanism common to neurodegeneration in ALS and SMA, and may explain cell-type specific vulnerability of motor neurons.


Assuntos
Esclerose Amiotrófica Lateral/metabolismo , Atrofia Muscular Espinal/metabolismo , Spliceossomos/metabolismo , Esclerose Amiotrófica Lateral/genética , Animais , Núcleo Celular/genética , Núcleo Celular/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Humanos , Camundongos , Camundongos Knockout , Neurônios Motores/metabolismo , Atrofia Muscular Espinal/genética , Ligação Proteica , RNA Nuclear Pequeno/genética , RNA Nuclear Pequeno/metabolismo , Proteína FUS de Ligação a RNA/genética , Proteína FUS de Ligação a RNA/metabolismo , Proteínas do Complexo SMN/genética , Proteínas do Complexo SMN/metabolismo , Spliceossomos/genética
4.
J Biol Chem ; 286(24): 21478-87, 2011 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-21527636

RESUMO

In adult rat brains, brain-derived neurotrophic factor (BDNF) rhythmically oscillates according to the light-dark cycle and exhibits unique functions in particular brain regions. However, little is known of this subject in juvenile rats. Here, we examined diurnal variation in BDNF and neurotrophin-3 (NT-3) levels in 14-day-old rats. BDNF levels were high in the dark phase and low in the light phase in a majority of brain regions. In contrast, NT-3 levels demonstrated an inverse phase relationship that was limited to the cerebral neocortex, including the visual cortex, and was most prominent on postnatal day 14. An 8-h phase advance of the light-dark cycle and sleep deprivation induced an increase in BDNF levels and a decrease in NT-3 levels in the neocortex, and the former treatment reduced synaptophysin expression and the numbers of synaptophysin-positive presynaptic terminals in cortical layer IV and caused abnormal BDNF and NT-3 rhythms 1 week after treatment. A similar reduction of synaptophysin expression was observed in the cortices of Bdnf gene-deficient mice and Ca(2+)-dependent activator protein for secretion 2 gene-deficient mice with abnormal free-running rhythm and autistic-like phenotypes. In the latter mice, no diurnal variation in BDNF levels was observed. These results indicate that regular rhythms of BDNF and NT-3 are essential for correct cortical network formation in juvenile rodents.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/metabolismo , Regulação da Expressão Gênica , Neurotrofina 3/metabolismo , Animais , Encéfalo/metabolismo , Cálcio/metabolismo , Córtex Cerebral/metabolismo , Masculino , Camundongos , Modelos Neurológicos , Fotoperíodo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Ratos Sprague-Dawley , Sinapses/metabolismo
5.
FEBS J ; 278(10): 1651-61, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21385318

RESUMO

The kinase noncatalytic C-lobe domain (KIND) is a putative protein-protein interaction module. Four KIND-containing proteins, Spir-2 (actin-nuclear factor), PTPN13 (protein tyrosine phosphatase), FRMPD2 (scaffold protein) and very-KIND (v-KIND) (brain-specific Ras guanine nucleotide exchange factor), have been identified to date. Uniquely, v-KIND has two KINDs (i.e. KIND1 and KIND2), whereas the other three proteins have only one. The functional role of KIND, however, remains unclear. We previously demonstrated that v-KIND interacts with the high-molecular weight microtubule-associated protein 2 (MAP2), a dendritic microtubule-associated protein, leading to negative regulation of neuronal dendrite growth. In the present study, we analyzed the structure-function relationships of the v-KIND-MAP2 interaction by generating a series of mutant constructs. The interaction with endogenous MAP2 in mouse cerebellar granule cells was specific to v-KIND KIND2, but not KIND1, and was not observed for the KINDs from other KIND-containing proteins. The binding core modules critical for the v-KIND-MAP2 interaction were defined within 32 residues of the mouse v-KIND KIND2 and 43 residues of the mouse MAP2 central domain. Three Leu residues at amino acid positions 461, 474 and 477 in the MAP2-binding core module of KIND2 contributed to the interaction. The MAP2-binding core module itself promoted dendrite branching as a dominant-negative regulator of v-KIND in hippocampal neurons. The results reported in the present study demonstrate the structural and functional determinant underlying the v-KIND-MAP2 interaction that controls dendrite arborization patterns.


Assuntos
Dendritos/fisiologia , Hipocampo/citologia , Proteínas Associadas aos Microtúbulos/metabolismo , Estrutura Terciária de Proteína , Fatores ras de Troca de Nucleotídeo Guanina/metabolismo , Sequência de Aminoácidos , Animais , Galinhas , Humanos , Leucina/química , Camundongos , Proteínas Associadas aos Microtúbulos/química , Neurônios/fisiologia , Mapeamento de Interação de Proteínas , Proteína Tirosina Fosfatase não Receptora Tipo 13/metabolismo , Fatores ras de Troca de Nucleotídeo Guanina/química
6.
Proc Natl Acad Sci U S A ; 108(1): 373-8, 2011 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-21173225

RESUMO

Calcium-dependent activator protein for secretion 2 (CAPS2) is a dense-core vesicle-associated protein that is involved in the secretion of BDNF. BDNF has a pivotal role in neuronal survival and development, including the development of inhibitory neurons and their circuits. However, how CAPS2 affects BDNF secretion and its biological significance in inhibitory neurons are largely unknown. Here we reveal the role of CAPS2 in the regulated secretion of BDNF and show the effect of CAPS2 on the development of hippocampal GABAergic systems. We show that CAPS2 is colocalized with BDNF, both synaptically and extrasynaptically in axons of hippocampal neurons. Overexpression of exogenous CAPS2 in hippocampal neurons of CAPS2-KO mice enhanced depolarization-induced BDNF exocytosis events in terms of kinetics, frequency, and amplitude. We also show that in the CAPS2-KO hippocampus, BDNF secretion is reduced, and GABAergic systems are impaired, including a decreased number of GABAergic neurons and their synapses, a decreased number of synaptic vesicles in inhibitory synapses, and a reduced frequency and amplitude of miniature inhibitory postsynaptic currents. Conversely, excitatory neurons in the CAPS2-KO hippocampus were largely unaffected with respect to field excitatory postsynaptic potentials, miniature excitatory postsynaptic currents, and synapse number and morphology. Moreover, CAPS2-KO mice exhibited several GABA system-associated deficits, including reduced late-phase long-term potentiation at CA3-CA1 synapses, decreased hippocampal theta oscillation frequency, and increased anxiety-like behavior. Collectively, these results suggest that CAPS2 promotes activity-dependent BDNF secretion during the postnatal period that is critical for the development of hippocampal GABAergic networks.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Hipocampo/citologia , Interneurônios/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Transmissão Sináptica/fisiologia , Animais , Proteínas de Ligação ao Cálcio/genética , Células Cultivadas , Eletrofisiologia , Imuno-Histoquímica , Interneurônios/fisiologia , Potenciação de Longa Duração/fisiologia , Camundongos , Camundongos Knockout , Microscopia Eletrônica , Proteínas do Tecido Nervoso/genética , Imagem com Lapso de Tempo
7.
J Cell Biol ; 179(3): 539-52, 2007 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-17984326

RESUMO

The regulation of cytoskeletal components in the dendritic shaft core is critical for dendrite elongation and branching. Here, we report that a brain-specific Ras guanine nucleotide exchange factor (RasGEF) carrying two kinase non-catalytic C-lobe domains (KINDs), very-KIND (v-KIND), regulates microtubule-associated protein 2 (MAP2). v-KIND is expressed in developing mouse brain, predominantly in the cerebellar granule cells. v-KIND not only activates Ras small GTPases via the C-terminal RasGEF domain, but also specifically binds to MAP2 via the second KIND domain (KIND2), leading to threonine phosphorylation of MAP2. v-KIND overexpression suppresses dendritic extension and branching of hippocampal neurons and cerebellar granule cells, whereas knockdown of endogenous v-KIND expression promotes dendrite growth. These findings suggest that v-KIND mediates a signaling pathway that links Ras and MAP2 to control dendrite growth.


Assuntos
Fatores de Troca do Nucleotídeo Guanina/fisiologia , Proteínas Associadas aos Microtúbulos/fisiologia , Proteínas do Tecido Nervoso/fisiologia , Fatores ras de Troca de Nucleotídeo Guanina/metabolismo , Animais , Encéfalo/metabolismo , Catálise , Cerebelo/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Camundongos , Proteínas Associadas aos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Modelos Biológicos , Proteínas do Tecido Nervoso/metabolismo , Fosforilação , Ligação Proteica , Estrutura Terciária de Proteína , Transdução de Sinais , Distribuição Tecidual
8.
J Cell Biol ; 164(5): 729-38, 2004 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-14981094

RESUMO

Drosophila melanogaster neuroblasts (NBs) undergo asymmetric divisions during which cell-fate determinants localize asymmetrically, mitotic spindles orient along the apical-basal axis, and unequal-sized daughter cells appear. We identified here the first Drosophila mutant in the Ggamma1 subunit of heterotrimeric G protein, which produces Ggamma1 lacking its membrane anchor site and exhibits phenotypes identical to those of Gbeta13F, including abnormal spindle asymmetry and spindle orientation in NB divisions. This mutant fails to bind Gbeta13F to the membrane, indicating an essential role of cortical Ggamma1-Gbeta13F signaling in asymmetric divisions. In Ggamma1 and Gbeta13F mutant NBs, Pins-Galphai, which normally localize in the apical cortex, no longer distribute asymmetrically. However, the other apical components, Bazooka-atypical PKC-Par6-Inscuteable, still remain polarized and responsible for asymmetric Miranda localization, suggesting their dominant role in localizing cell-fate determinants. Further analysis of Gbetagamma and other mutants indicates a predominant role of Partner of Inscuteable-Galphai in spindle orientation. We thus suggest that the two apical signaling pathways have overlapping but different roles in asymmetric NB division.


Assuntos
Proteínas de Transporte/metabolismo , Divisão Celular/fisiologia , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/fisiologia , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular , Neurônios/fisiologia , Proteína Quinase C/metabolismo , Sistemas do Segundo Mensageiro/fisiologia , Sequência de Aminoácidos , Animais , Animais Geneticamente Modificados , Proteínas de Ciclo Celular/metabolismo , Polaridade Celular , Tamanho Celular , Proteínas do Citoesqueleto/genética , Proteínas do Citoesqueleto/metabolismo , Drosophila melanogaster/embriologia , Embrião não Mamífero/fisiologia , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/genética , Subunidades beta da Proteína de Ligação ao GTP/genética , Subunidades beta da Proteína de Ligação ao GTP/metabolismo , Isoenzimas/metabolismo , Substâncias Macromoleculares , Dados de Sequência Molecular , Neurônios/citologia , Neuropeptídeos , Mutação Puntual , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Proteínas/genética , Proteínas/metabolismo , Fuso Acromático/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA