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1.
Life Sci ; 242: 117151, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31843526

RESUMO

AIMS: Anaesthesia-related neurotoxicity in the developing brain is a controversial issue that has recently attracted much attention. Hemin plays a protective role in hypoxic and ischemic brain damage; however, its effects on sevoflurane-induced neurotoxicity remain unclear. Our aim was to investigate the mechanisms of sevoflurane neurotoxicity and potential neuroprotective roles of hemin upon sevoflurane exposure. MAIN METHODS: Hippocampi were harvested 18 h after sevoflurane exposure. Haem oxygenase 1 (HMOX1), superoxide dismutase 2 (SOD2), discs large MAGUK scaffold protein 4 (DLG4), phosphorylated Akt, Akt, cleaved caspase 3, and neuroglobin were detected by western blotting. A water maze test was used to assess learning and memory ability in P30 rats. KEY FINDINGS: Sevoflurane inhalation increased cleaved caspase 3 levels. Hemin treatment enhanced the antioxidant defence response, protecting rats from oxidative stress injury. Hemin plays its neuroprotective role via phosphoinositide 3-kinase (PI3K)/Akt signalling. A single inhalation of sevoflurane did not affect DLG4 expression, while hemin treatment did. Platform crossing increased in rats treated with hemin as well, which may be related to increased DLG4. Neuroglobin expression was not affected, suggesting that it may act upstream of PI3K/Akt signalling. SIGNIFICANCE: Our study demonstrates that hemin plays a protective role in anaesthesia-induced neurotoxicity by both inhibiting apoptosis via the PI3K/Akt pathway and increasing the expression of antioxidant enzymes, reducing oxidative damage. The results provide mechanistic insight into the effects of sevoflurane anaesthesia on the developing brain and suggest that hemin could help avoid these effects.


Assuntos
Anestésicos Inalatórios/toxicidade , Encéfalo/efeitos dos fármacos , Hemina/farmacologia , Fármacos Neuroprotetores/farmacologia , Fosfatidilinositol 3-Quinase/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Sevoflurano/toxicidade , Transdução de Sinais/efeitos dos fármacos , Administração por Inalação , Animais , Animais Recém-Nascidos , Western Blotting , Caspase 3/metabolismo , Proteína 4 Homóloga a Disks-Large/metabolismo , Heme Oxigenase (Desciclizante)/metabolismo , Hipocampo/química , Hipocampo/efeitos dos fármacos , Hipocampo/enzimologia , Aprendizagem em Labirinto/efeitos dos fármacos , Neuroglobina/metabolismo , Ratos , Ratos Sprague-Dawley , Sevoflurano/antagonistas & inibidores , Superóxido Dismutase/metabolismo
2.
Nat Commun ; 10(1): 4521, 2019 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-31586061

RESUMO

Designing highly specific modulators of protein-protein interactions (PPIs) is especially challenging in the context of multiple paralogs and conserved interaction surfaces. In this case, direct generation of selective and competitive inhibitors is hindered by high similarity within the evolutionary-related protein interfaces. We report here a strategy that uses a semi-rational approach to separate the modulator design into two functional parts. We first achieve specificity toward a region outside of the interface by using phage display selection coupled with molecular and cellular validation. Highly selective competition is then generated by appending the more degenerate interaction peptide to contact the target interface. We apply this approach to specifically bind a single PDZ domain within the postsynaptic protein PSD-95 over highly similar PDZ domains in PSD-93, SAP-97 and SAP-102. Our work provides a paralog-selective and domain specific inhibitor of PSD-95, and describes a method to efficiently target other conserved PPI modules.


Assuntos
Anticorpos/química , Domínios PDZ , Peptídeos/química , Engenharia de Proteínas , Mapas de Interação de Proteínas/efeitos dos fármacos , Animais , Anticorpos/farmacologia , Células COS , Proteína 4 Homóloga a Disks-Large/antagonistas & inibidores , Proteína 4 Homóloga a Disks-Large/metabolismo , Desenho de Drogas , Mapeamento de Epitopos , Modelos Moleculares , Biblioteca de Peptídeos , Peptídeos/farmacologia , Ligação Proteica , Proteínas Recombinantes/metabolismo
3.
Nat Commun ; 10(1): 4377, 2019 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-31558769

RESUMO

Synapses contain hundreds of distinct proteins whose heterogeneous expression levels are determinants of synaptic plasticity and signal transmission relevant to a range of diseases. Here, we use diffusible nucleic acid imaging probes to profile neuronal synapses using multiplexed confocal and super-resolution microscopy. Confocal imaging is performed using high-affinity locked nucleic acid imaging probes that stably yet reversibly bind to oligonucleotides conjugated to antibodies and peptides. Super-resolution PAINT imaging of the same targets is performed using low-affinity DNA imaging probes to resolve nanometer-scale synaptic protein organization across nine distinct protein targets. Our approach enables the quantitative analysis of thousands of synapses in neuronal culture to identify putative synaptic sub-types and co-localization patterns from one dozen proteins. Application to characterize synaptic reorganization following neuronal activity blockade reveals coordinated upregulation of the post-synaptic proteins PSD-95, SHANK3 and Homer-1b/c, as well as increased correlation between synaptic markers in the active and synaptic vesicle zones.


Assuntos
Microscopia de Fluorescência/métodos , Neurônios/metabolismo , Sondas de Ácido Nucleico/metabolismo , Oligonucleotídeos/metabolismo , Animais , Animais Recém-Nascidos , Células Cultivadas , Difusão , Proteína 4 Homóloga a Disks-Large/metabolismo , Camundongos , Proteínas do Tecido Nervoso/metabolismo , Plasticidade Neuronal , Neurônios/citologia , Sondas de Ácido Nucleico/química , Oligonucleotídeos/química , Ratos Sprague-Dawley , Sinapses/metabolismo , Vesículas Sinápticas/metabolismo
4.
J Nat Med ; 73(4): 717-726, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31190266

RESUMO

Tau oligomers are the etiologic molecules of Alzheimer's disease, and correlate strongly with neuronal loss and exhibit neurotoxicity. Recent evidence indicates that small tau oligomers are the most relevant toxic aggregate species. The aim of the present study was to investigate the mechanisms of cornel iridoid glycoside (CIG) on tau oligomers and cognitive functions. We injected wortmannin and GF-109203X (WM/GFX, 200 µM each) into the lateral ventricles to induce tau oligomer and memory impairment in rats. When orally administered with CIG at 60 and 120 mg/kg/day for 14 days, CIG decreased the escape latency in the Morris water maze test. We also found that CIG restored the expression of presynaptic p-synapsin, synaptophysin, and postsynaptic density-95 (PSD-95) decreased by WM/GFX in rat cortex. CIG reduced the accumulation of tau oligomers in the brain of WM/GFX rats and in cells transfected with wild type glycogen synthase kinase-3ß (wtGSK-3ß). In addition, CIG up-regulated the levels of ATG7, ATG12, Beclin-1, and LC3II in vivo and in vitro, suggesting the restoration of autophagy function. These results suggest that CIG could ameliorate memory deficits and regulate memory-associated synaptic proteins through the clearance of tau oligomers accumulation. Moreover, CIG clears tau oligomers by restoring autophagy function.


Assuntos
Doença de Alzheimer/patologia , Glicogênio Sintase Quinase 3 beta/metabolismo , Glicosídeos Iridoides/farmacologia , Transtornos da Memória/patologia , Proteínas tau/toxicidade , Animais , Autofagia/efeitos dos fármacos , Encéfalo/metabolismo , Linhagem Celular Tumoral , Proteína 4 Homóloga a Disks-Large/metabolismo , Indóis/toxicidade , Masculino , Maleimidas/toxicidade , Aprendizagem em Labirinto/efeitos dos fármacos , Memória/efeitos dos fármacos , Camundongos , Fosforilação , Substâncias Protetoras , Ratos , Ratos Wistar , Sinapsinas/metabolismo , Sinaptofisina/metabolismo , Wortmanina/toxicidade
5.
Cell Mol Neurobiol ; 39(7): 1003-1015, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31187311

RESUMO

Atrazine (ATR), a widely used herbicide, has been previously shown to damage spatial memory capability and the hippocampus of male rats during the development. It has also been indicated that physical exercise can improve learning and memory in both humans and animals, as a neuroprotective method. Our aim here was to investigate the effect of maternal ATR exposure during gestation and lactation on spatial learning and memory function and hippocampal morphology in offspring and to further evaluate the neuroprotective effect of swimming training and identify possible related learning and memory signaling pathways. Using Sprague-Dawley rats, we examined behavioral and molecular biology effects associated with maternal ATR exposure, as well as the effects of 8 or 28 days swimming training. Maternal exposure to ATR was found to impair spatial learning and memory by behavioral test, damage the hippocampal morphology, and reduce related genes and proteins expression of learning and memory in the hippocampus. The extended, 28 days, period of swimming training produced a greater amelioration of the adverse effects of ATR exposure than the shorter, 8 days, training period. Our results suggest that maternal ATR exposure may damage the spatial learning and memory of offspring male rats via PSD95/NR2B signaling pathway. The negative effect of ATR could be at least partially reversed by swimming training, pointing to a potential neuroprotective role of physical exercise in nervous system diseases accompanying by learning and memory deficit.


Assuntos
Atrazina/toxicidade , Hipocampo/patologia , Exposição Materna , Transdução de Sinais , Aprendizagem Espacial , Memória Espacial/efeitos dos fármacos , Natação , Animais , Peso Corporal/efeitos dos fármacos , Proteína 4 Homóloga a Disks-Large/genética , Proteína 4 Homóloga a Disks-Large/metabolismo , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Força da Mão , Hipocampo/efeitos dos fármacos , Hipocampo/ultraestrutura , Masculino , Gravidez , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Ratos Sprague-Dawley , Tempo de Reação/efeitos dos fármacos , Receptores de N-Metil-D-Aspartato/genética , Receptores de N-Metil-D-Aspartato/metabolismo , Aprendizagem Espacial/efeitos dos fármacos
6.
Int J Nanomedicine ; 14: 4059-4069, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31213815

RESUMO

Background and purpose: Traumatic brain injury (TBI) is a major disease without effective treatment. Recently, Tat-NR2B9c peptide emerged as a promising neuroprotective agent, but limited in clinical translation by it low brain penetrability. We synthesized Tat-NR2B9c loaded self-assembled activatable protein nanoparticles, termed TN-APNPs, and demonstrated that TN-APNPs enhanced the delivery of Tat-NR2B9c to the brain lesion in stroke. Herein we developed a novel approach to further engineering TN-APNPs for targeted delivery of Tat-NR2B9c to the injured brain with enhanced efficiency through conjugation of CAQK or CCAQK, a short peptide. Methods: Short peptide-conjugated TN-APNPs were synthesized by conjugated with CAQK or CCAQK via a click condensation reaction with CBT, then analyzed by dynamic light scattering, transmission electron microscopy and thrombin responsive assay. Characterization of short peptide-conjugated TN-APNPs were investigated by using cell excitotoxicity assay and transwell blood-brain-barrier model in vitro, and pharmacokinetics, IVIS imaging system and confocal analysis in TBI-bearing mice. Evaluation of therapeutic effects were analyzed by H&E staining, Elevated Plus Maze analysis and Rotarod test. Results: CAQK-conjugated TN-APNPs (C-TN-APNPs) and CCAQK-conjugated TN-APNPs (CC-TN-APNPs) were spherical in morphology and 30 nm in diameter. In vitro studies revealed that TN-APNPs, C-TN-APNPs and CC-TN-APNPs were responsive to thrombin cleavage, reduced the cytotoxicity of Tat-NR2B9c, and increased BBB permeability of Tat-NR2B9c. CC-TN-APNPs demonstrated the better circulation time, better targeting ability and penetrating efficiency to the injured brain, and better therapeutic benefits in vivo studies. Conclusion: This study demonstrated CC-TN-APNPs as a promising therapeutic for clinical management of TBI.


Assuntos
Lesões Encefálicas Traumáticas/tratamento farmacológico , Nanopartículas/química , Peptídeos/uso terapêutico , Animais , Lesões Encefálicas Traumáticas/patologia , Linhagem Celular Tumoral , Modelos Animais de Doenças , Proteína 4 Homóloga a Disks-Large/metabolismo , Portadores de Fármacos/química , Humanos , Masculino , Camundongos Endogâmicos C57BL , Nanopartículas/ultraestrutura , Peptídeos/síntese química , Peptídeos/farmacologia , Teste de Desempenho do Rota-Rod , Trombina/uso terapêutico
7.
Biomed Pharmacother ; 116: 109054, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31176122

RESUMO

BACKGROUND: Depression is a common disease that endangers people's physical and mental health. Traditional Chinese medicine has advantages in treating the emotional and cognitive symptoms of depressive disorders. OBJECTIVE: To study the effects of baicalin on the behavior and to clarify the underlying mechanism through evaluation of the Rac1-LIMK1-cofilin pathway. METHODS: A chronic mild stress (CMS) model of depression was used. Baicalin was administered to the mice for the intervention, and the positive control group was treated with fluoxetine. Behavioral tests were conducted to observe the degree of depressive disorders. Synaptophysin (SYP), postsynaptic density protein-95 (PSD95), brain-derived neurotrophic factor (BDNF), tyrosine kinase receptors (TrkB), Rac1 and cofilin expression was determined using Western blot analysis, and mRNA was quantified using real-time PCR. RESULTS: Mice in the CMS group showed an increase in depression-like behavior (p < 0.01), while mice in the baicalin and fluoxetine groups showed a decrease in depression-like behavior (p < 0.01), compared with the control group. Electron microscopy showed ultrastructural changes in the hippocampal CA3 area of the CMS group, which were alleviated by baicalin treatment. SYP, PSD95, BDNF, TrkB, Rac1 and cofilin protein expression levels were decreased in the CMS group compared with the control group, while these levels were increased in the baicalin and fluoxetine groups (p < 0.01). There was no significant difference among the baicalin and fluoxetine groups (p > 0.05). CONCLUSION: Baicalin markedly alleviated depression-like behavioral changes, exerted effects on SYP, PSD95, BDNF, and TrkB expression, activated the Rac1-cofilin pathway, and subsequently improve synaptic plasticity.


Assuntos
Fatores de Despolimerização de Actina/metabolismo , Comportamento Animal , Depressão/tratamento farmacológico , Flavonoides/uso terapêutico , Quinases Lim/metabolismo , Transdução de Sinais , Estresse Psicológico/tratamento farmacológico , Proteínas rac de Ligação ao GTP/metabolismo , Animais , Comportamento Animal/efeitos dos fármacos , Fator Neurotrófico Derivado do Encéfalo/genética , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Doença Crônica , Depressão/complicações , Proteína 4 Homóloga a Disks-Large/genética , Proteína 4 Homóloga a Disks-Large/metabolismo , Flavonoides/química , Flavonoides/farmacologia , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Hipocampo/ultraestrutura , Masculino , Camundongos , Neurônios/efeitos dos fármacos , Neurônios/patologia , Neurônios/ultraestrutura , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptor trkB/metabolismo , Transdução de Sinais/efeitos dos fármacos , Estresse Psicológico/complicações , Natação , Sinaptofisina/genética , Sinaptofisina/metabolismo
8.
PLoS One ; 14(5): e0217275, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31112584

RESUMO

Fragile X syndrome, the most common inherited form of intellectual disability, is caused by the CGG trinucleotide expansion in the 5'-untranslated region of the Fmr1 gene on the X chromosome, which silences the expression of the fragile X mental retardation protein (FMRP). FMRP has been shown to bind to a G-rich region within the PSD-95 mRNA, which encodes for the postsynaptic density protein 95, and together with microRNA-125a to mediate the reversible inhibition of the PSD-95 mRNA translation in neurons. The miR-125a binding site within the PSD-95 mRNA 3'-untranslated region (UTR) is embedded in a G-rich region bound by FMRP, which we have previously demonstrated folds into two parallel G-quadruplex structures. The FMRP regulation of PSD-95 mRNA translation is complex, being mediated by its phosphorylation. While the requirement for FMRP in the regulation of PSD-95 mRNA translation is clearly established, the exact mechanism by which this is achieved is not known. In this study, we have shown that both unphosphorylated FMRP and its phosphomimic FMRP S500D bind to the PSD-95 mRNA G-quadruplexes with high affinity, whereas only FMRP S500D binds to miR-125a. These results point towards a mechanism by which, depending on its phosphorylation status, FMRP acts as a switch that potentially controls the stability of the complex formed by the miR-125a-guided RNA induced silencing complex (RISC) and PSD-95 mRNA.


Assuntos
Proteína 4 Homóloga a Disks-Large/biossíntese , Proteína do X Frágil de Retardo Mental/metabolismo , MicroRNAs/metabolismo , RNA Mensageiro/metabolismo , Substituição de Aminoácidos , Sequência de Bases , Sítios de Ligação/genética , Proteína 4 Homóloga a Disks-Large/genética , Proteína do X Frágil de Retardo Mental/química , Proteína do X Frágil de Retardo Mental/genética , Síndrome do Cromossomo X Frágil/genética , Síndrome do Cromossomo X Frágil/metabolismo , Quadruplex G , Humanos , MicroRNAs/química , MicroRNAs/genética , Modelos Moleculares , Fosforilação , Ligação Proteica , Biossíntese de Proteínas , RNA Mensageiro/química , RNA Mensageiro/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
9.
Chemosphere ; 229: 618-630, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31102917

RESUMO

Bisphenol-A (BPA) is a representative exogenous endocrine disruptor, which is extensively composed in plastic products. Due to the capability of passing through the blood-brain barrier, evidence has linked BPA exposure with multiple neuropsychological dysfunctions, neurobehavioral disorders and neurodegenerative diseases. However, the underlying mechanism by which BPA induces neurodegeneration still remains unclear. Our study used human embryonic stem cells-derived human cortical neurons (hCNs) as a cellular model to investigate the adverse neurotoxic effects of BPA. hCNs were treated with 0, 0.1, 1 and 10 µM BPA for 14 days. Impacts of BPA exposure on cell morphology, cell viability and neural marker (MAP2) were measured for evaluating the neurodegeneration. The intracellular calcium homeostasis, reactive oxygen species (ROS) generation and organelle functions were also taken into consideration. Results revealed that chronic exposure of BPA damaged the neural morphology, induced neuronal apoptosis and decreased MAP2 expression at the level of both transcription and translation. The intracellular calcium levels were elevated in hCNs after BPA exposure through NMDARs-nNOS-PSD-95 mediating. Meanwhile, BPA led to oxidative stress by raising the ROS generation and attenuating the antioxidant defense in hCNs. Furthermore, BPA triggered ER stress and increased cytochrome c release by impairing the mitochondrial function. Ultimately, BPA triggered the cell apoptosis by regulating Bcl-2 family and caspase-dependent signaling pathway. Taken together, BPA exerted neurotoxic effects on hCNs by eliciting apoptosis, which might due to the intracellular calcium homeostasis perturbation and cell organellar dysfunction.


Assuntos
Compostos Benzidrílicos/toxicidade , Cálcio/metabolismo , Células-Tronco Embrionárias Humanas/citologia , Neurônios/efeitos dos fármacos , Fenóis/toxicidade , Animais , Apoptose/efeitos dos fármacos , Células Cultivadas , Proteína 4 Homóloga a Disks-Large/metabolismo , Homeostase/efeitos dos fármacos , Humanos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Óxido Nítrico Sintase Tipo I/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo
10.
eNeuro ; 6(2)2019.
Artigo em Inglês | MEDLINE | ID: mdl-31068362

RESUMO

Mutations and copy number variants of the CUB and Sushi multiple domains 2 (CSMD2) gene are associated with neuropsychiatric disease. CSMD2 encodes a single-pass transmembrane protein with a large extracellular domain comprising repeats of CUB and Sushi domains. High expression of CSMD2 in the developing and mature brain suggests possible roles in neuron development or function, but the cellular functions of CSMD2 are not known. In this study, we show that mouse Csmd2 is expressed in excitatory and inhibitory neurons in the forebrain. Csmd2 protein exhibits a somatodendritic localization in the neocortex and hippocampus, with smaller puncta localizing to the neuropil. Using immunohistochemical and biochemical methods, we demonstrate that Csmd2 localizes to dendritic spines and is enriched in the postsynaptic density (PSD). Accordingly, we show that the cytoplasmic tail domain of Csmd2 interacts with synaptic scaffolding proteins of the membrane-associated guanylate kinase (MAGUK) family. The association between Csmd2 and MAGUK member PSD-95 is dependent on a PDZ-binding domain on the Csmd2 tail, which is also required for synaptic targeting of Csmd2. Finally, we show that knock-down of Csmd2 expression in hippocampal neuron cultures results in reduced complexity of dendritic arbors and deficits in dendritic spine density. Knock-down of Csmd2 in immature developing neurons results in reduced filopodia density, whereas Csmd2 knock-down in mature neurons causes significant reductions in dendritic spine density and dendrite complexity. Together, these results point toward a function for Csmd2 in development and maintenance of dendrites and synapses, which may account for its association with certain psychiatric disorders.


Assuntos
Espinhas Dendríticas/metabolismo , Proteína 4 Homóloga a Disks-Large/metabolismo , Hipocampo/metabolismo , Proteínas de Membrana/metabolismo , Neocórtex/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurônios/fisiologia , Densidade Pós-Sináptica/metabolismo , Animais , Células Cultivadas , Feminino , Hipocampo/citologia , Masculino , Proteínas de Membrana/deficiência , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Proteínas do Tecido Nervoso/deficiência , Neurônios/metabolismo , Pseudópodes/metabolismo
11.
Eur J Histochem ; 63(2)2019 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-31060348

RESUMO

Cognitive impairment in Alzheimer's disease (AD) is usually accompanied by synaptic loss in both the hippocampus and neocortex. In the early stage of AD, amyloid ß-induced synapse changes is the main reason, while in the later stage, the accumulation of Tau protein promotes synapse degeneration as the key factor leading to dementia. MicroRNA (miRNA) is closely related to the expression changes of many AD-related genes. One of the most abundant brain-enriched miRNAs is miR-132, which has been shown to regulate both neuron morphogenesis and plasticity. It has been reported that miR-132 is significantly reduced in the brains of Alzheimer's patients. Genetic deletion of miR-132 in mice promotes Aß deposition, leading to impaired memory and enhanced Tau pathology, but how the miRNA-mediated gene expression dysregulation contributes to AD pathology remains unclear. Here we found the possible downstream target of miR-132 by in silico analysis, namely C1q. C1q is the primary protein of classical complement cascade, which is highly expressed in the synaptic regions of the central nervous system in Alzheimer's patients. However, it is not clear whether miR-132 plays a role in AD through regulating C1q. To address this question, the APP/PS1 transgenic mice were transfected with miR-132 and given C1 inhibitors. Behavior tests were conducted to assess memory and cognitive abilities seven days after administration. In addition, we analyzed the expression of PSD95, Synapsin-1 and phosphorylated (p)-Synapsin. We found that the expression levels of the synaptic proteins treated with miR-132 or C1INH were significantly increased compared with the AD group. Further RT-qPCR result suggested that miR-132 might regulate C1q expression in AD.


Assuntos
Precursor de Proteína beta-Amiloide/genética , Complemento C1q/metabolismo , MicroRNAs/metabolismo , Presenilina-1/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/fisiopatologia , Animais , Cognição/efeitos dos fármacos , Complemento C1q/antagonistas & inibidores , Complemento C1q/genética , Proteína 4 Homóloga a Disks-Large/genética , Proteína 4 Homóloga a Disks-Large/metabolismo , Reposicionamento de Medicamentos , Regulação da Expressão Gênica , Masculino , Memória/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Sinapsinas/genética , Sinapsinas/metabolismo
12.
Nat Commun ; 10(1): 2167, 2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-31092821

RESUMO

Ribbon synapses transmit information in sensory systems, but their development is not well understood. To test the hypothesis that ribbon assembly stabilizes nascent synapses, we performed simultaneous time-lapse imaging of fluorescently-tagged ribbons in retinal cone bipolar cells (BCs) and postsynaptic densities (PSD95-FP) of retinal ganglion cells (RGCs). Ribbons and PSD95-FP clusters were more stable when these components colocalized at synapses. However, synapse density on ON-alpha RGCs was unchanged in mice lacking ribbons (ribeye knockout). Wildtype BCs make both ribbon-containing and ribbon-free synapses with these GCs even at maturity. Ribbon assembly and cone BC-RGC synapse maintenance are thus regulated independently. Despite the absence of synaptic ribbons, RGCs continued to respond robustly to light stimuli, although quantitative examination of the responses revealed reduced frequency and contrast sensitivity.


Assuntos
Células Fotorreceptoras Retinianas Cones/fisiologia , Sinapses/metabolismo , Transmissão Sináptica/fisiologia , Animais , Células Cultivadas , Proteína 4 Homóloga a Disks-Large/genética , Proteína 4 Homóloga a Disks-Large/metabolismo , Microscopia Intravital/métodos , Luz , Proteínas Luminescentes/química , Proteínas Luminescentes/genética , Camundongos , Camundongos Transgênicos , Microscopia de Fluorescência/métodos , Estimulação Luminosa , Cultura Primária de Células , Células Bipolares da Retina/fisiologia , Células Ganglionares da Retina/fisiologia , Imagem com Lapso de Tempo/métodos
13.
Neurobiol Aging ; 79: 66-74, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31029017

RESUMO

Metabolic conditions during brain development may have long-term consequences on brain metabolism, thereby influencing the risk of neurodegenerative disease in later life. To ascertain the long-term consequences of omega-3 (ω3) fatty acid deficiency during brain development on oxidative fatty acid degradation in the brain and the development of Alzheimer-like pathology, wild-type (WT) female mice were fed diets that were either replete or deficient in ω3 fatty acids for 5 weeks. These females were then mated with hemizygous 5xFAD male transgenic (TG) mouse models of Alzheimer's disease, and the progeny were continued on diets that were either ω3-replete or ω3-deficient. When the progeny were 6 months of age, they received radiolabeled arachidonic acid (ARA) by intracerebroventricular injection. Five days after these injections, the brains were harvested and oxidative degradation of the radiolabeled ARA was characterized. Among the progeny of female mice on an ω3-replete diet, TG progeny had lower PSD-95 expression and higher oxidative ARA degradation than WT progeny. Progeny on an ω3-deficient diet, however, had no significant differences in PSD-95 expression between TG and WT mice, or in the extent of ARA degradation. In TG mice, an ω3-deficient diet reduced oxidative ARA degradation to a greater extent than in WT mice. The reductions in oxidative ARA degradation occurred even if the progeny of female mice on an ω3-deficient diet resumed an ω3-replete diet immediately on weaning. These results demonstrate that dietary ω3 fatty acid deficiency during development can cause long-term changes in the expression of a synaptic marker and long-term reductions in the rate of ARA degradation in the WT brain, which are not completely alleviated by an ω3-replete diet after weaning. The elimination of differences between TG and WT mice by an ω3-deficient diet suggests that mechanisms regulating PSD-95 expression and the oxidative degradation of ARA are related and that the timing of dietary ω3 intake during development may influence Alzheimer's disease-related pathological changes later in life.


Assuntos
Doença de Alzheimer/etiologia , Doença de Alzheimer/metabolismo , Encéfalo/metabolismo , Ácidos Graxos Ômega-3/deficiência , Ácidos Graxos/metabolismo , Animais , Ácido Araquidônico/administração & dosagem , Ácido Araquidônico/metabolismo , Modelos Animais de Doenças , Proteína 4 Homóloga a Disks-Large/genética , Proteína 4 Homóloga a Disks-Large/metabolismo , Ácidos Graxos Ômega-3/administração & dosagem , Feminino , Expressão Gênica , Injeções Intraventriculares , Masculino , Camundongos Transgênicos , Oxirredução , Estresse Oxidativo
14.
Int J Mol Sci ; 20(6)2019 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-30934587

RESUMO

Alzheimer's disease (AD) is the most common neurodegenerative disorder affecting 5.4 million people in the United States. Currently approved pharmacologic interventions for AD are limited to symptomatic improvement, not affecting the underlying pathology. Therefore, the search for novel therapeutic strategies is ongoing. A hallmark of AD is the compromised blood-brain barrier (BBB); thus, developing drugs that target the BBB to enhance its integrity and function could be a novel approach to prevent and/or treat AD. Previous evidence has shown the beneficial effects of growth factors in the treatment of AD pathology. Based on reported positive results obtained with the product Endoret®, the objective of this study was to investigate the effect of plasma rich in growth factors (PRGF) on the BBB integrity and function, initially in a cell-based BBB model and in 5x Familial Alzheimer's Disease (5xFAD) mice. Our results showed that while PRGF demonstrated a positive effect in the cell-based BBB model with the enhanced integrity and function of the model, the in-vivo findings showed that PRGF exacerbated amyloid pathology in 5xFAD brains. At 10 and 100% doses, PRGF increased amyloid deposition associated with increased apoptosis and neuroinflammation. In conclusion, our results suggest PRGF may not provide beneficial effects against AD and the consideration to utilize growth factors should further be investigated.


Assuntos
Amiloide/metabolismo , Barreira Hematoencefálica/patologia , Peptídeos e Proteínas de Sinalização Intercelular/efeitos adversos , Plasma/química , Peptídeos beta-Amiloides/metabolismo , Animais , Astrócitos/metabolismo , Biomarcadores/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Proteína 4 Homóloga a Disks-Large/metabolismo , Mediadores da Inflamação/metabolismo , Radioisótopos do Iodo , Camundongos Transgênicos , Transporte Proteico , Fator A de Crescimento do Endotélio Vascular/metabolismo
15.
PLoS One ; 14(4): e0215004, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30973894

RESUMO

Alzheimer's disease currently lacks treatment options that effectively reverse the biological/anatomical pathology and cognitive deficits associated with the disease. Loss of function of the nuclear receptor REV-ERB is associated with reduced cognitive function in mouse models. The effect of enhanced REV-ERB activity on cognitive function has not been examined. In this study, we tested the hypothesis that enhanced REV-ERB function may enhance cognitive function in a model of Alzheimer's disease. We utilized the REV-ERB agonist SR9009 to pharmacologically activate the activity of REV-ERB in the SAMP8 mouse model of Alzheimer's disease. SR9009 reversed cognitive dysfunction of an aged SAMP8 mouse in several behavioral assays including novel object recognition, T-maze foot shock avoidance, and lever press operant conditioning task assessments. SR9009 treatment reduced amyloid-ß 1-40 and 1-42 levels in the cortex, which is consistent with improved cognitive function. Furthermore, SR9009 treatment led to increased hippocampal PSD-95, cortical synaptophysin expression and the number of synapses suggesting improvement in synaptic function. We conclude that REV-ERB is a potential target for treatment of Alzheimer's disease.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides/metabolismo , Disfunção Cognitiva , Membro 1 do Grupo D da Subfamília 1 de Receptores Nucleares/metabolismo , Fragmentos de Peptídeos/metabolismo , Pirrolidinas/farmacologia , Tiofenos/farmacologia , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Animais , Disfunção Cognitiva/tratamento farmacológico , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/patologia , Modelos Animais de Doenças , Proteína 4 Homóloga a Disks-Large/metabolismo , Hipocampo/metabolismo , Hipocampo/patologia , Masculino , Camundongos
16.
Acta Crystallogr D Struct Biol ; 75(Pt 4): 381-391, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30988255

RESUMO

PDZ domains are protein-protein recognition modules that interact with other proteins through short sequences at the carboxyl terminus. These domains are structurally characterized by a conserved fold composed of six ß-strands and two α-helices. The third PDZ domain of the neuronal postsynaptic density protein 95 has an additional α-helix (α3), the role of which is not well known. In previous structures, a succinimide was identified in the ß2-ß3 loop instead of Asp332. The presence of this modified residue results in conformational changes in α3. In this work, crystallographic structures of the following have been solved: a truncated form of the third PDZ domain of the neuronal postsynaptic density protein 95 from which α3 has been removed, D332P and D332G variants of the protein, and a new crystal form of this domain showing the binding of Asp332 to the carboxylate-binding site of a symmetry-related molecule. Crystals of the wild type and variants were obtained in different space groups, which reflects the conformational plasticity of the domain. Indeed, the overall analysis of these structures suggests that the conformation of the ß2-ß3 loop is correlated with the fold acquired by α3. The alternate conformation of the ß2-ß3 loop affects the electrostatics of the carboxylate-binding site and might modulate the binding of different PDZ-binding motifs.


Assuntos
Cristalografia por Raios X/métodos , Proteína 4 Homóloga a Disks-Large/química , Domínios PDZ , Conformação Proteica , Sítios de Ligação , Domínio Catalítico , Proteína 4 Homóloga a Disks-Large/metabolismo , Humanos , Modelos Moleculares , Estrutura Molecular , Ligação Proteica
17.
Nutrients ; 11(4)2019 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-30979047

RESUMO

Unhealthy diet promotes progression of metabolic disorders and brain dysfunction with aging. Green tea extracts (GTEs) have various beneficial effects and alleviate metabolic disorders. GTEs have neuroprotective effects in rodent models, but their effects against brain dysfunction in models of aging fed unhealthy diets are still unclear. Here, we showed that GTEs attenuate high-fat (HF) diet-induced brain dysfunction in senescence-accelerated mouse prone-8 (SAMP8), a murine model of senescence. SAMP8 mice were fed a control diet, HF diet, or HF diet with 0.5% GTEs (HFGT) for four months. The HF diet reduced memory retention and induced amyloid ß1-42 accumulation, whereas GTEs attenuated these changes. In HF diet-fed mice, lipid oxidative stress, assessed by malondialdehyde levels, was increased. The levels of proteins that promote synaptic plasticity, such as brain-derived neurotrophic factor (BDNF) and postsynaptic density protein 95 (PSD95), were reduced. These alterations related to brain dysfunction were not observed in HFGT diet-fed mice. Overall, our data suggest that GTEs intake might attenuate brain dysfunction in HF diet-fed SAMP8 mice by protecting synaptic plasticity as well as via anti-oxidative effects. In conclusion, GTEs might ameliorate unhealthy diet-induced brain dysfunction that develops with aging.


Assuntos
Encefalopatias/tratamento farmacológico , Dieta Hiperlipídica/efeitos adversos , Fármacos Neuroprotetores , Extratos Vegetais/administração & dosagem , Chá , Envelhecimento , Peptídeos beta-Amiloides/análise , Animais , Encéfalo/patologia , Química Encefálica , Encefalopatias/etiologia , Encefalopatias/fisiopatologia , Fator Neurotrófico Derivado do Encéfalo/análise , Disfunção Cognitiva/tratamento farmacológico , Disfunção Cognitiva/etiologia , Proteína 4 Homóloga a Disks-Large/análise , Masculino , Memória , Camundongos , Plasticidade Neuronal , Tamanho do Órgão , Estresse Oxidativo/efeitos dos fármacos , Fitoterapia , Sinaptofisina/análise
18.
Cell Physiol Biochem ; 52(2): 232-239, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30816671

RESUMO

BACKGROUND/AIMS: Pterostilbene (Pt; trans-3,5-dimethoxy-4'-hydroxystilbene) is a natural phenol found in blueberries and grapevines. It shows remarkable biomedical activities similar to those of resveratrol. Its high bioavailability is a major advantage for possible biomedical applications. The goal of the study was to evaluate the effects of chronic pterostilbene administration on cognitive performance in aged rats with mild cognitive impairment. METHODS: 18-month-old animals were subjected to behavioral tests to establish the "baseline", then divided into treatment and control groups. The former were chronically fed Pt (22.5 mg/kg-day) for 20 consecutive days. At the end of this period all animals were tested again and sacrificed. The dentate gyrus, the hippocampus and the prefrontal and perirhinal cortices were then collected, and RT-qPCR and/or Western blot analyses were performed on a few transcripts/proteins involved in synaptic remodeling. Mitochondrial content was also assessed. RESULTS: Pt administration improved performance in behavioral tests and positively affected memory consolidation. We found increased levels of REST, PSD-95 and mitochondrial porin1 in the dentate gyrus and a positive correlation between T-maze test score and levels of cAMP responsive element binding protein (CREB) phosphorylation. CONCLUSION: These results underscore the therapeutic potential of Pt supplementation for age-related cognitive decline.


Assuntos
Envelhecimento/metabolismo , Comportamento Animal/efeitos dos fármacos , Cognição/efeitos dos fármacos , Aprendizagem em Labirinto/efeitos dos fármacos , Estilbenos/farmacologia , Animais , Proteína de Ligação a CREB/metabolismo , Disfunção Cognitiva/tratamento farmacológico , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/patologia , Giro Denteado/metabolismo , Proteína 4 Homóloga a Disks-Large/biossíntese , Ratos , Proteínas Repressoras/biossíntese
19.
J Agric Food Chem ; 67(10): 3006-3017, 2019 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-30816709

RESUMO

Alzheimer's disease (AD) is closely related to gut microbial alteration. Prebiotic fructooligosaccharides (FOS) play major roles by regulating gut microbiota. The present study aimed to explore the effect and mechanism of FOS protection against AD via regulating gut microbiota. Male Apse/PSEN 1dE9 (APP/PS1) transgenic (Tg) mice were administrated with FOS for 6 weeks. Cognitive deficits and amyloid deposition were evaluated. The levels of synaptic plasticity markers including postsynaptic density protein 95 (PSD-95) and synapsin I, as well as phosphorylation of c-Jun N-terminal kinase (JNK), were determined. The intestinal microbial constituent was detected by 16S rRNA sequencing. Moreover, the levels of glucagon-like peptide-1 (GLP-1) in the gut and GLP-1 receptor (GLP-1R) in the brain were measured. The results indicated that FOS treatment ameliorated cognitive deficits and pathological changes in the Tg mice. FOS significantly upregulated the expression levels of synapsin I and PSD-95, as well as decreased phosphorylated level of JNK. The sequencing results showed that FOS reversed the altered microbial composition. Furthermore, FOS increased the level of GLP-1 and decreased the level of GLP-1R in the Tg mice. These findings indicated that FOS exerted beneficial effects against AD via regulating the gut microbiota-GLP-1/GLP-1R pathway.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/microbiologia , Microbioma Gastrointestinal/efeitos dos fármacos , Oligossacarídeos/administração & dosagem , Prebióticos/administração & dosagem , Doença de Alzheimer/metabolismo , Doença de Alzheimer/psicologia , Peptídeos beta-Amiloides/genética , Peptídeos beta-Amiloides/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Cognição , Modelos Animais de Doenças , Proteína 4 Homóloga a Disks-Large/metabolismo , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Plasticidade Neuronal , Presenilina-1/genética , Presenilina-1/metabolismo , Sinapsinas/metabolismo
20.
Neurosci Lett ; 703: 156-161, 2019 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-30926374

RESUMO

It has been suggested that interactions of neuronal nitric oxide synthase (nNOS) with postsynaptic density 95 (PSD95) play important roles in the development of chronic neuropathic pain. Here we examine the possible role of nNOS-PSD95 interactions in central sensitization as represented by phosphorylation of the NMDA receptor GluN1 subunit (pGluN1) in mice with chronic constriction injury (CCI) of the sciatic nerve. Intrathecal administration of the nNOS-PSD95 interactions inhibitor, IC87201 on post-operative days 0-3 significantly reduced the CCI-induced increase in total NO levels in the lumbar spinal cord dorsal horn. IC87201 administration on post-operative days 0-3 also attenuated the CCI-induced development of mechanical allodynia (MA) and PKC-dependent (Ser896) pGluN1. Sciatic nerve injury elicited a significant translocation of the PKC-ε isoform from the cytosol to the membrane fraction in the lumbar spinal cord dorsal horn on day 3 post-CCI surgery. Administration of IC87201 significantly inhibited this translocation of PKC-ε, while the expression of PKC-α and -ξ in the cytosol and membrane fractions was unaffected by sciatic nerve injury or injection of IC87201. Furthermore, administration of the PKC-ε inhibitor, εV1-2 on post-operative days 0-3 attenuated the CCI-induced development of MA and pGluN1. Collectively these results demonstrate that spinal nNOS-PSD95 interactions play an important role in PKC-dependent GluN1 phosphorylation via activation of the PKC-ε isoform, and ultimately contributes to the development of MA in peripheral neuropathy.


Assuntos
Proteína 4 Homóloga a Disks-Large/metabolismo , Hiperalgesia/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neuralgia/metabolismo , Óxido Nítrico Sintase Tipo I/metabolismo , Proteína Quinase C-épsilon/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Animais , Ativação Enzimática , Isoenzimas/metabolismo , Masculino , Camundongos Endogâmicos ICR , Fosforilação , Estimulação Física , Nervo Isquiático/lesões , Tato
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