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1.
J Virol ; 98(3): e0139223, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38363111

RESUMO

Although it is widely accepted that herpesviruses utilize host RNA polymerase II (RNAPII) to transcribe viral genes, the mechanism of utilization varies significantly among herpesviruses. With the exception of herpes simplex virus 1 (HSV-1) in alpha-herpesviruses, the mechanism by which RNAPII transcribes viral genes in the remaining alpha-herpesviruses has not been reported. In this study, we investigated the transcriptional mechanism of an avian alpha-herpesvirus, Anatid herpesvirus 1 (AnHV-1). We discovered for the first time that hexamethylene-bis-acetamide-inducing protein 1 (HEXIM1), a major inhibitor of positive elongation factor B (P-TEFb), was significantly upregulated during AnHV-1 infection, and its expression was dynamically regulated throughout the progression of the disease. However, the expression level of HEXIM1 remained stable before and after HSV-1 infection. Excessive HEXIM1 assists AnHV-1 in progeny virus production, gene expression, and RNA polymerase II recruitment by promoting the formation of more inactive P-TEFb and the loss of RNAPII S2 phosphorylation. Conversely, the expression of some host survival-related genes, such as SOX8, CDK1, MYC, and ID2, was suppressed by HEXIM1 overexpression. Further investigation revealed that the C-terminus of the AnHV-1 US1 gene is responsible for the upregulation of HEXIM1 by activating its promoter but not by interacting with P-TEFb, which is the mechanism adopted by its homologs, HSV-1 ICP22. Additionally, the virus proliferation deficiency caused by US1 deletion during the early infection stage could be partially rescued by HEXIM1 overexpression, suggesting that HEXIM1 is responsible for AnHV-1 gaining transcription advantages when competing with cells. Taken together, this study revealed a novel HEXIM1-dependent AnHV-1 transcription mechanism, which has not been previously reported in herpesvirus or even DNA virus studies.IMPORTANCEHexamethylene-bis-acetamide-inducing protein 1 (HEXIM1) has been identified as an inhibitor of positive transcriptional elongation factor b associated with cancer, AIDS, myocardial hypertrophy, and inflammation. Surprisingly, no previous reports have explored the role of HEXIM1 in herpesvirus transcription. This study reveals a mechanism distinct from the currently known herpesvirus utilization of RNA polymerase II, highlighting the dependence on high HEXIM1 expression, which may be a previously unrecognized facet of the host shutoff manifested by many DNA viruses. Moreover, this discovery expands the significance of HEXIM1 in pathogen infection. It raises intriguing questions about whether other herpesviruses employ similar mechanisms to manipulate HEXIM1 and if this molecular target can be exploited to limit productive replication. Thus, this discovery not only contributes to our understanding of herpesvirus infection regulation but also holds implications for broader research on other herpesviruses, even DNA viruses.


Assuntos
Anseriformes , Fator B de Elongação Transcricional Positiva , Proteínas de Ligação a RNA , Fatores de Transcrição , Herpesvirus Humano 1/genética , Herpesvirus Humano 1/metabolismo , Fator B de Elongação Transcricional Positiva/genética , Fator B de Elongação Transcricional Positiva/metabolismo , RNA Polimerase II/genética , RNA Polimerase II/metabolismo , Proteínas de Ligação a RNA/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcrição Gênica , Transcrição Viral , Animais
3.
Bioorg Med Chem Lett ; 98: 129576, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38061401

RESUMO

Alzheimer's disease (AD) is a common type of neurodegenerative disease, which can only be symptomatically relieved but does not yet have a cure. Among the different Aß species, amyloid-ß 42 (Aß42) aggregates are proposed to be more neurotoxic than that of Aß40, and oligomeric Aß42 is thought to play a harmful role in the pathophysiology of AD. Therefore, the detection of Aß42 aggregation is very meaningful in the AD field. We herein report a conformationally-locked p- hydroxybenzylidene imidazolinone derivative, BDI, which exhibits selectivity and specificity towards Aß42 aggregation and remarkable fluorescent enhancement with a large Stokes shift (more than 100 nm). In the fluorescent co-localization study, BDI can sensitively detect a large population of Aß42 aggregation over that of Aß40 in the brain tissues of AD transgenic mouse models. Therefore, this new probe could provide a useful tool for the rapid detection of important Aß species in AD.


Assuntos
Doença de Alzheimer , Doenças Neurodegenerativas , Animais , Camundongos , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/efeitos dos fármacos , Corantes , Fragmentos de Peptídeos , Imidazóis/química , Imidazóis/farmacologia
4.
Stud Health Technol Inform ; 308: 155-167, 2023 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-38007737

RESUMO

Gastric cancer is a malignant tumor with high incidence and death rate. Every year, Approximately 950,000 new cases of gastric cancer occur globally with nearly 700000 deaths,so gastric precancerous lesions(GPL) was crucial and important.At present, the effective diagnostic methods for gastric precancerous lesions are generally gastroscope and pathological changes of gastric mucosal, but those methods were invasive and would bring some pains to patients and not suitable for frequent and large-scale screening of gastric cancer or GPL.This study aimed to look for a sensitive,effective and non-invasive diagnostic method to improve the early diagnosis rate of GLP, and thereby reduce the incidence and death rate of gastric cancer.Tongue diagnosis is one of the classic diagnostic methods in traditional Chinese medicine(TCM).The tongue was closely related to the spleen and stomach.In the study, we collected 133 patients with chronic gastritis, including 53 cases in inflammatory group, 31 cases in atrophic group, and 49 cases in intestinal metaplasia group. and we analyzed the correlation between tongue,microbiota of tongue coating and clinical symptoms of GLP.The results showed that greasy coating was closely related to the intestinal metaphase of patients, indicating that greasy coating was closed link with intestinal metaphase phase of patients.Abundance of 209 genus were significant differences between greasy and non-greasy coating in intestinal metaphase phase of patients, Top10 were Streptococcus,norank_p__Saccharibacteria,Alloprevotella, Atopobium, Megasphaera, Gemella, Moraxella,unclassified_f__Prevotellaceae, Solobacterium and Stomatobaculum. Alloprevotella and Streptococcus were important genus markers and Alloprevotella was selected as a potential oral biomarker to diagnose intestinal metaphase phase of patients, the AUC value is 0.74.


Assuntos
Gastrite , Lesões Pré-Cancerosas , Neoplasias Gástricas , Humanos , Gastrite/diagnóstico , Gastrite/microbiologia , Gastrite/patologia , Neoplasias Gástricas/diagnóstico , Neoplasias Gástricas/patologia , Metáfase , Biomarcadores , Lesões Pré-Cancerosas/microbiologia
5.
Neuropharmacology ; 235: 109576, 2023 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-37164226

RESUMO

The cumulative evidence suggests that oxytocin is involved in the male sexual behaviors. However, no significant sexual impairments were observed in oxytocin gene knock-out (KO) mice, suggesting that oxytocin is not necessary for sexual behavior in male mice. To better understand the role of oxytocin in male erection, two types of oxytocin gene KO mice were created. In the first type, the oxytocin gene was deleted in the zygote, while in the second type, the oxytocin gene was mutated in adulthood by injecting the CRISPR/Cas9 AAVs. The results showed that disrupting the oxytocin gene at either the embryonic or adult stage did not affect erection, indicating that oxytocin is not necessary for penile erection. Pharmacologically, injecting oxytocin receptor agonist Carbetocin into the VTA of the oxytocin gene KO mice still evoked penile erection. By employing the Oxt-Ires-Cre mice, we found that specifically activating oxytocinergic neurons through chemogenetics strongly induced penile erection, while inhibiting these neurons blocked the erection responses. Furthermore, ablating PVN oxytocinergic neurons abolished the male erection response. In conclusion, although the neuropeptide oxytocin is not essential for male erection, the activity of oxytocinergic neurons is required. Our results might reflect the redundancy in the central nerve system in the sense that many signals contribute to the activation of oxytocinergic neurons to evoke penile erection during sexual behaviors.


Assuntos
Neurônios , Ocitocina , Ereção Peniana , Animais , Masculino , Camundongos , Neurônios/fisiologia , Núcleo Hipotalâmico Paraventricular , Ereção Peniana/fisiologia , Receptores de Ocitocina/genética , Ocitocina/metabolismo
6.
BMC Genomics ; 23(1): 509, 2022 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-35836133

RESUMO

BACKGROUND: Duck plague virus (DPV), belonging to herpesviruses, is a linear double-stranded DNA virus. There are many reports about the outbreak of the duck plague in a variety of countries, which caused huge economic losses. Recently, increasing reports revealed that multiple long non-coding RNAs (lncRNAs) can possess great potential in the regulation of host antiviral immune response. Furthermore, it remains to be determined which specific molecular mechanisms are responsible for the DPV-host interaction in host immunity. Here, lncRNAs and mRNAs in DPV infected duck embryonic fibroblast (DEF) cells were identified by high-throughput RNA-sequencing (RNA-seq). And we predicted target genes of differentially expressed genes (DEGs) and formed a complex regulatory network depending on in-silico analysis and prediction. RESULT: RNA-seq analysis results showed that 2921 lncRNAs were found at 30 h post-infection (hpi). In our study, 218 DE lncRNAs and 2840 DE mRNAs were obtained in DEF after DPV infection. Among these DEGs and target genes, some have been authenticated as immune-related molecules, such as a Macrophage mannose receptor (MR), Anas platyrhynchos toll-like receptor 2 (TLR2), leukocyte differentiation antigen, interleukin family, and their related regulatory factors. Furthermore, according to the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analysis, we found that the target genes may have important effects on biological development, biosynthesis, signal transduction, cell biological regulation, and cell process. Also, we obtained, the potential targeting relationship existing in DEF cells between host lncRNAs and DPV-encoded miRNAs by software. CONCLUSIONS: This study revealed not only expression changes, but also the possible biological regulatory relationship of lncRNAs and mRNAs in DPV infected DEF cells. Together, these data and analyses provide additional insight into the role of lncRNAs and mRNAs in the host's immune response to DPV infection.


Assuntos
Patos/embriologia , Fibroblastos/virologia , Doença de Marek/virologia , Doenças das Aves Domésticas/virologia , RNA Longo não Codificante/metabolismo , RNA Mensageiro/metabolismo , Animais , Surtos de Doenças/veterinária , Patos/genética , Patos/virologia , Fibroblastos/metabolismo , Perfilação da Expressão Gênica , Infecções por Herpesviridae/metabolismo , Mardivirus , Doença de Marek/epidemiologia , Doença de Marek/imunologia , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/imunologia , RNA Longo não Codificante/análise , RNA Longo não Codificante/genética , RNA Mensageiro/análise , RNA Mensageiro/genética
7.
Anal Chem ; 94(4): 1999-2006, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-35041386

RESUMO

ß-Amyloid deposition is one of the main pathological features of Alzheimer's disease (AD). The development of fluorescent probes targeting specific ß-amyloid species has recently become an attractive strategy to achieve the early diagnosis of AD. In this work, a dual-channel fluorescent protein chromophore derivative C17 was rationally designed and synthesized for the detection and discrimination of Aß42 aggregates and oligomers. C17 exhibits a specific turn-on emission peak for Aß42 oligomers at ∼470 nm (peak A) and a peak at ∼600 nm (peak B) for both Aß42 oligomers and Aß42 aggregates. Taking advantage of the dual emission of the probe, the dynamic aggregation process of the Aß42 peptide was monitored in solution. Moreover, double staining of brain sections from transgenic AD mice revealed that peak A of C17 preferentially detected Aß42 oligomers, whereas peak B was more sensitive to Aß42 aggregates. The fact that probe C17 can be used for dissecting these two Aß42 species makes C17 a comprehensive tool for ß-amyloid aggregation studies in AD research.


Assuntos
Doença de Alzheimer , Fragmentos de Peptídeos , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Encéfalo/metabolismo , Camundongos , Camundongos Transgênicos , Fragmentos de Peptídeos/metabolismo , Agregados Proteicos
8.
Anal Chim Acta ; 1133: 109-118, 2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-32993862

RESUMO

Alzheimer's disease (AD) is a chronic neurodegenerative disease. Better imaging and early diagnosis of biomarkers of AD is extremely important for therapeutic interventions. The amyloid cascade hypothesis and its revised version identify insoluble ß-amyloid deposition as a good diagnostic biomarker for AD. Moreover, lipid droplets may also act as an auxiliary biomarker related to AD pathology based on recent studies. Herein, two quinoline-based AIE probes were designed and synthesized for the imaging of Aß plaques and lipid droplets. The probes exhibited remarkable turn-on fluorescence enhancements with the Aß aggregates. The lipid droplets-targeting probe FB exhibited high selectivity and binding affinity towards the Aß aggregates with a detection limit as low as 26.9 nM. Furthermore, FB was capable of readily imaging Aß plaques and lipid droplets at the cellular level and in brain sections of transgenic AD mice. The probe FB can serve as a promising tool for developing early diagnosis and innovative therapeutics of AD.


Assuntos
Doença de Alzheimer , Doenças Neurodegenerativas , Doença de Alzheimer/diagnóstico por imagem , Peptídeos beta-Amiloides/metabolismo , Animais , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Corantes Fluorescentes , Gotículas Lipídicas/metabolismo , Camundongos , Camundongos Transgênicos , Placa Amiloide/diagnóstico por imagem
9.
Analyst ; 145(20): 6579-6585, 2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-32780031

RESUMO

Aberrant accumulation of Amyloid-ß (Aß) peptide is closely related to Alzheimer's disease. Thus, it is important to develop featured probes for the specific detection of Aß species. Herein, we designed and synthesized a novel near-infrared fluorescent probe SDPY based on the D-π-A architecture for the detection of Aß aggregates. The probe SDPY displayed higher affinity for Aß40 aggregates over Aß42 aggregates in solution (Kd = 164 nM vs. 2.1 µM). In addition, SDPY showed excellent anti-interference against a wide range of other substances. Furthermore, SDPY was capable of labeling Aß40 aggregates better than Aß42 aggregates in the brain sections of AD transgenic mouse models.


Assuntos
Doença de Alzheimer , Corantes Fluorescentes , Doença de Alzheimer/diagnóstico , Peptídeos beta-Amiloides/metabolismo , Animais , Encéfalo/metabolismo , Camundongos , Camundongos Transgênicos , Fragmentos de Peptídeos
11.
J Mater Chem B ; 7(36): 5535-5540, 2019 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-31451829

RESUMO

Two quinoline-malononitrile-based NIR fluorescent probes with good water-solubility have been developed for detecting and imaging of Aß aggregates in Alzheimer's disease. In vitro studies demonstrated that both probes exhibited high affinity to Aß aggregates with an increase of fluorescence intensity due to the intramolecular charge transfer effect. Moreover, the probes could particularly image Aß plaques in brain sections of triple transgenic AD mice.


Assuntos
Doença de Alzheimer/diagnóstico , Peptídeos beta-Amiloides/química , Corantes Fluorescentes/química , Água/química , Animais , Raios Infravermelhos , Camundongos , Camundongos Transgênicos , Estrutura Molecular , Tamanho da Partícula , Agregados Proteicos , Teoria Quântica , Solubilidade , Propriedades de Superfície
12.
Chem Sci ; 8(12): 8279-8284, 2017 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-29619173

RESUMO

Alzheimer's disease (AD) is the most prevalent but still incurable neurodegenerative form of dementia. Early diagnosis and intervention are crucial for delaying the onset and progression of the disease. We herein report a novel fluoro-substituted cyanine, F-SLOH, which exhibits good Aß oligomer selectivity with a high binding affinity, attributed to the synergistic effect of strong π-π stacking and intermolecular CH···O and CH···F interactions. The selectivity towards the Aß oligomers in the brain was ascertained by in vitro labelling on tissue sections and in vivo labelling through the systemic administration of F-SLOH in 7 month APP/PS1 double transgenic (Tg) and APP/PS1/Tau triple Tg mouse models. F-SLOH also shows remarkably effective inhibition on Aß aggregation and highly desirable neuroprotective effects against Aß-induced toxicities, including the inhibition of ROS production and Ca2+ influx. Its excellent blood-brain barrier (BBB) penetrability and low bio-toxicity further support its tremendous potential as a novel theranostic agent for both early diagnosis and therapy of AD.

13.
Chem Commun (Camb) ; 52(57): 8865-8, 2016 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-27346489

RESUMO

We report a new spiropyran-based fluorescent probe that exhibits high affinity and specificity towards Aß oligomers both in vitro and in vivo. This probe can penetrate the blood brain barrier and specifically target Aß oligomers in the brains of transgenic mice in models for Alzheimer's disease.


Assuntos
Doença de Alzheimer/diagnóstico , Peptídeos beta-Amiloides/análise , Benzopiranos/química , Corantes Fluorescentes/química , Indóis/química , Nitrocompostos/química , Animais , Benzopiranos/administração & dosagem , Modelos Animais de Doenças , Fluorescência , Corantes Fluorescentes/administração & dosagem , Indóis/administração & dosagem , Injeções Intraperitoneais , Camundongos , Camundongos Transgênicos , Estrutura Molecular , Nitrocompostos/administração & dosagem , Teoria Quântica
14.
Elife ; 4: e06734, 2015 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-25821988

RESUMO

Autophagy is an important intracellular catabolic mechanism involved in the removal of misfolded proteins. Atg14L, the mammalian ortholog of Atg14 in yeast and a critical regulator of autophagy, mediates the production PtdIns3P to initiate the formation of autophagosomes. However, it is not clear how Atg14L is regulated. In this study, we demonstrate that ubiquitination and degradation of Atg14L is controlled by ZBTB16-Cullin3-Roc1 E3 ubiquitin ligase complex. Furthermore, we show that a wide range of G-protein-coupled receptor (GPCR) ligands and agonists regulate the levels of Atg14L through ZBTB16. In addition, we show that the activation of autophagy by pharmacological inhibition of GPCR reduces the accumulation of misfolded proteins and protects against behavior dysfunction in a mouse model of Huntington's disease. Our study demonstrates a common molecular mechanism by which the activation of GPCRs leads to the suppression of autophagy and a pharmacological strategy to activate autophagy in the CNS for the treatment of neurodegenerative diseases.


Assuntos
Compostos Heterocíclicos/farmacologia , Doença de Huntington/tratamento farmacológico , Doença de Huntington/genética , Fatores de Transcrição Kruppel-Like/genética , Receptores CXCR4/genética , Proteínas de Transporte Vesicular/genética , Animais , Autofagia/efeitos dos fármacos , Autofagia/genética , Proteínas Relacionadas à Autofagia , Benzilaminas , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Linhagem Celular Tumoral , Cromonas/farmacologia , Proteínas Culina/genética , Proteínas Culina/metabolismo , Ciclamos , Modelos Animais de Doenças , Regulação da Expressão Gênica , Células HEK293 , Humanos , Doença de Huntington/mortalidade , Doença de Huntington/patologia , Fatores de Transcrição Kruppel-Like/metabolismo , Camundongos , Morfolinas/farmacologia , Fagossomos , Fosfatos de Fosfatidilinositol/biossíntese , Proteína com Dedos de Zinco da Leucemia Promielocítica , Complexo de Endopeptidases do Proteassoma/efeitos dos fármacos , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise/efeitos dos fármacos , Desempenho Psicomotor/efeitos dos fármacos , Receptores CXCR4/antagonistas & inibidores , Receptores CXCR4/metabolismo , Teste de Desempenho do Rota-Rod , Transdução de Sinais , Análise de Sobrevida , Ubiquitinação , Proteínas de Transporte Vesicular/metabolismo
15.
PLoS One ; 10(3): e0120217, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25781629

RESUMO

Previous studies reported that the expression of miR-23b-27b cluster was downregulated in embryonic brain cortices during hypoxia-induced neuronal apoptosis. However, the mechanism underlying this downregulation is not completely understood. Here, we report that the transcription factor c-Myc plays an important role in regulating the expression of miR-23b-27b cluster during hypoxia. First, the c-Myc protein level was significantly elevated in embryonic brain cortices in a mouse model of fetal distress. Second, forced overexpression or knockdown of c-Myc could suppress or increase the expression of miR-23b-27b cluster polynucleotides. Third, we identified 2 conserved c-Myc binding sites (E-boxes) in the enhancer and promoter regions of miR-23b-27b cluster in the mouse genome. Finally, we showed that elevated c-Myc expression led to an increase in the Apaf-1 level by suppressing miR-23b-27b cluster expression and that this enhanced neuronal sensitivity to apoptosis. In summary, our study demonstrates that c-Myc may suppress the expression of the miR-23b-27b cluster, resulting in additional neuronal apoptosis during hypoxia.


Assuntos
Apoptose , MicroRNAs/biossíntese , Neurônios/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Transcrição Gênica , Animais , Hipóxia Celular , Camundongos , Elementos de Resposta
16.
Chem Commun (Camb) ; 51(1): 125-8, 2015 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-25384304

RESUMO

Two fluorescent switchable diarylethene derivatives which exhibit high affinity for amyloid-ß aggregates with the increase of fluorescence intensity were reported. Moreover, the probes show excellent photochromic and anti-photobleaching properties both in vitro and in vivo.


Assuntos
Peptídeos beta-Amiloides/análise , Corantes Fluorescentes/química , Microscopia de Fluorescência , Doença de Alzheimer/patologia , Encéfalo/metabolismo , Encéfalo/patologia , Curcumina/química , Corantes Fluorescentes/síntese química , Humanos
17.
Eur J Neurosci ; 34(2): 177-89, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21749491

RESUMO

Cocaine relapse can occur when cocaine-associated environmental cues induce craving. Conditioned place preference (CPP) is a behavioral paradigm modeling the association between cocaine exposure and environmental cues. The amygdala is involved in cocaine cue associations with the basolateral amygdala (BLA) and central amygdala (CeA) acting differentially in cue-induced relapse. Activation of metabotropic glutamate receptors induces synaptic plasticity, the mechanism of which is thought to underlie learning, memory and drug-cue associations. The goal of this study was to examine the neural alterations in responses to group I metabotropic glutamate receptor (mGluR) agonists in the BLA to lateral capsula of CeA (BLA-CeLc) pathway in slices from rats exposed to cocaine-CPP conditioning and withdrawn for 14 days. mGluR1, but not mGluR5, agonist-induced long-term potentiation (mGluR1-LTP) in the BLA-CeLc pathway was reduced in rats withdrawal from cocaine for 2 and 14 days, and exhibited an altered concentration response to picrotoxin. Cocaine withdrawal also reduced γ-aminobutyric acid (GABA)ergic synaptic inhibition in CeLc neurons. Blocking cannabinoid receptor 1 (CB(1) ) reduced mGluR1-LTP in the saline-treated but not cocaine-withdrawn group. Response to CB(1) but not CB(2) agonist was altered after cocaine. Additionally, increasing endocannabinoid (eCB) levels abolished mGluR1-LTP in the saline but not cocaine-withdrawn group. However, CB(1) and CB(2) protein levels were increased in the amygdala of cocaine-withdrawn rats while mGluR1 and mGluR5 remained unchanged. These data suggested that the mechanisms underlying the diminished mGluR1-LTP in cocaine-withdrawn rats involve an altered GABAergic synaptic inhibition mediated by modulation of downstream eCB signaling. These changes may ultimately result in potentiated responses to environmental cues that would bias behavior toward drug-seeking.


Assuntos
Tonsila do Cerebelo/fisiologia , Cocaína/farmacologia , Potenciação de Longa Duração/efeitos dos fármacos , Receptores de Glutamato Metabotrópico/metabolismo , Síndrome de Abstinência a Substâncias/fisiopatologia , Transmissão Sináptica/fisiologia , Ácido gama-Aminobutírico/metabolismo , Tonsila do Cerebelo/efeitos dos fármacos , Animais , Comportamento Animal/efeitos dos fármacos , Condicionamento Psicológico/efeitos dos fármacos , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Potenciais Pós-Sinápticos Excitadores/fisiologia , Antagonistas GABAérgicos/metabolismo , Potenciação de Longa Duração/fisiologia , Masculino , Técnicas de Patch-Clamp , Picrotoxina/metabolismo , Ratos , Ratos Sprague-Dawley , Receptor CB1 de Canabinoide/agonistas , Receptor CB1 de Canabinoide/análise , Receptor CB1 de Canabinoide/metabolismo , Receptor CB2 de Canabinoide/agonistas , Receptor CB2 de Canabinoide/análise , Receptor CB2 de Canabinoide/metabolismo , Receptor de Glutamato Metabotrópico 5 , Receptores de Glutamato Metabotrópico/agonistas , Receptores de N-Metil-D-Aspartato/metabolismo , Transmissão Sináptica/efeitos dos fármacos
18.
Neurobiol Aging ; 32(1): 42-53, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19233513

RESUMO

Thiamine pyrophosphate (TPP) and the activities of thiamine-dependent enzymes are reduced in Alzheimer's disease (AD) patients. In this study, we analyzed the relationship between thiamine deficiency (TD) and amyloid precursor protein (APP) processing in both cellular and animal models of TD. In SH-SY5Y neuroblastoma cells overexpressing APP, TD promoted maturation of ß-site APP cleaving enzyme 1 (BACE1) and increased ß-secretase activity which resulted in elevated levels of ß-amyloid (Aß) as well as ß-secretase cleaved C-terminal fragment (ß-CTF). An inhibitor of ß-secretase efficiently reduced TD-induced up-regulation of Aß and ß-CTF. Importantly, thiamine supplementation reversed the TD-induced alterations. Furthermore, TD treatment caused a significant accumulation of reactive oxygen species (ROS); antioxidants suppressed ROS production and maturation of BACE1, as well as TD-induced Aß accumulation. On the other hand, exogenous Aß(1-40) enhanced TD-induced production of ROS. A study on mice indicated that TD also caused Aß accumulation in the brain, which was reversed by thiamine supplementation. Taken together, our study suggests that TD could enhance Aß generation by promoting ß-secretase activity, and the accumulation of Aß subsequently exacerbated TD-induced oxidative stress.


Assuntos
Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Encéfalo/metabolismo , Deficiência de Tiamina/metabolismo , Deficiência de Tiamina/patologia , Peptídeos beta-Amiloides/farmacologia , Precursor de Proteína beta-Amiloide/metabolismo , Análise de Variância , Animais , Antioxidantes/uso terapêutico , Ácido Aspártico Endopeptidases/metabolismo , Morte Celular/fisiologia , Linhagem Celular Tumoral , Cromanos/uso terapêutico , Modelos Animais de Doenças , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/fisiologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neuroblastoma/patologia , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/farmacologia , Piritiamina/efeitos adversos , Espécies Reativas de Oxigênio/metabolismo , Tiamina/administração & dosagem , Deficiência de Tiamina/tratamento farmacológico , Deficiência de Tiamina/etiologia , Fatores de Tempo
19.
J Neurosci Res ; 88(1): 102-10, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19642195

RESUMO

The microtubule-associated protein tau has been implicated in beta-amyloid- and glutamate-induced neurotoxicity. However, the potential role of tau in response to other insults to neurons remains unclear. In this study, we examined whether deletion of tau would change cell injury induced by heat shock in primary cultures of cortical neurons. After 30 min of a 45 degrees C heat shock, lactate dehydrogenase (LDH) release increased, reaching a peak at 6 hr in wild-type (WT) neurons. A significantly lower LDH release, with a peak delayed by 24 hr, was detected in tau knockout (TKO) neurons. After heat shock treatment, MAP-2 and tubulin staining of the processes of WT neurons revealed more dramatic abnormalities than in TKO neurons. Both WT and TKO neurons exhibited a similar elevation of HSP70 level but different time courses of Akt phosphorylation. In contrast to an early, brief response in WT neurons, TKO neurons displayed a late, but long-lasting increase in phosphorylation of Akt and its downstream target, glycogen synthase kinase 3beta. Additionally, inhibition of Akt activity aggravated the cell morbidity caused by heat shock exposure in both WT and TKO neurons, indicating a protective role of Akt against cell injury. In conclusion, our results demonstrate that deletion of tau attenuated heat shock-induced neuronal injury. Enhanced Akt response in the absence of endogenous tau is suggested to represent a compensatory mechanism for regulating cell reactions to stress stimuli.


Assuntos
Córtex Cerebral/metabolismo , Resposta ao Choque Térmico/genética , Neurônios/metabolismo , Proteínas tau/genética , Análise de Variância , Animais , Western Blotting , Sobrevivência Celular , Células Cultivadas , Córtex Cerebral/citologia , Imunofluorescência , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Temperatura Alta , Camundongos , Camundongos Knockout , Neurônios/citologia , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fatores de Tempo , Proteínas tau/metabolismo
20.
J Neurochem ; 109(2): 476-84, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19200347

RESUMO

Truncated tau is widely detected in Alzheimer's disease brain, and caspase-3 has been considered as a major executioner for tau truncation at aspartate421 (D421), according to its capability of cleaving recombinant tau in vitro. Here we investigated the relationship between D421 truncated tau and caspase-3 in two transgenic mouse models for tauopathies. In adult transgenic mice, activated caspase-3 could not be detected in neurons containing truncated tau, with the exception of a few glia-like cells or neurons in postnatal mice. Caspase-3 expression exhibited a dramatic decrease at the early development stage, and kept at constantly low levels during adult stages in both wild type and transgenic mice. On the other hand, co-incubating brain homogenates from adult tau transgenic mice and ethanol-treated postnatal mice promoted tau truncation at D421, which was mildly reduced by caspase inhibitor, but completely suppressed by phosphatase inhibitor, indicating that hyperphosphorylated tau becomes a poor substrate for truncation at D421. Taken together, our study shows that insufficient caspase-3 expression and hyperphosphorylated status of tau in the adult transgenic mouse brain restrict caspase-3 as an efficient enzyme for tau truncation in vivo. Clearly, there is a caspase-3 independent mechanism responsible for tau truncation at D421 in these models.


Assuntos
Ácido Aspártico/metabolismo , Caspase 3/fisiologia , Tauopatias/enzimologia , Proteínas tau/metabolismo , Animais , Ácido Aspártico/genética , Caspase 3/química , Modelos Animais de Doenças , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Tauopatias/genética , Proteínas tau/química , Proteínas tau/genética
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