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1.
Int J Biol Macromol ; 254(Pt 1): 127579, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37918606

RESUMO

Silver nanoparticles (AgNPs) by green synthesis from fungi polysaccharides are attracting increasing attention owing to their distinctive features and special applications in numerous fields. In this study, a cost-effective and environmentally friendly biosynthesizing AgNPs method with no toxic chemicals involved from the fruiting body polysaccharide of Phlebopus portentosus (PPP) was established and optimized by single factor experiment and response surface methodology. The optimum synthesis conditions of polysaccharide-AgNPs (PPP-AgNPs) were identified to be the reaction time of 140 min, reaction temperature of 94 °C, and the PPP: AgNO3 ratio of 1:11.5. Formation of PPP-AgNPs was indicated by visual detection of colour change from yellowish to yellowish brown. PPP-AgNPs were characterized by different methods and further evaluated for biological activities. That the Ultraviolet-visible (UV-Vis.) spectroscopy displayed a sharp absorption peak at 420 nm confirmed the formation of AgNPs. Fourier transform infrared (FTIR) analysis detected the presence of various functional groups. The lattice indices of (111), (200), (220), and (331), which indicated a faced-centered-cubic of the Ag crystal structure of PPP-AgNPs, was confirmed by X-ray diffraction (XRD) and the particles were found to be spherical through high resolution transmission electron microscopy (HRTEM). Energy dispersive X-ray spectroscopy (EDS) determined the presence of silver in PPP-AgNPs. The percentage relative composition of elements was determined as silver (Ag) 82.5 % and oxygen (O) 17.5 % for PPP-AgNPs, and did not exhibit any nitrogen peaks. The specific surface area of PPP-AgNPs was calculated to be 0.5750 m2/g with an average pore size of 24.33 nm by BET analysis. The zeta potential was -4.32 mV, which confirmed the stability and an average particle size of 64.5 nm was calculated through dynamic light scattering (DLS). PPP-AgNPs exhibited significant free radical scavenging activity against DPPH with an IC50 value of 0.1082 mg/mL. The MIC values of PPP-AgNPs for E. coli, S. aureus, C. albicans, C. glabrata, and C. parapsilosis are 0.05 mg/mL. The IC50 value of the inhibition of PPP-AgNPs against α-glucosidase was 11.1 µg/mL, while the IC50 values of PPP-AgNPs against HepG2 and MDA-MB-231 cell lines were calculated to be 14.36 ± 0.43 µg/mL and 40.05 ± 2.71 µg/mL, respectively. According to the evaluation, it can be concluded that these green-synthesized and eco-friendly PPP-AgNPs are helpful to improve therapeutics because of significant antioxidant, antimicrobial, antidiabetic, and anticancer properties to provide new possibilities for clinic applications.


Assuntos
Anti-Infecciosos , Nanopartículas Metálicas , Prata/química , Antioxidantes/farmacologia , Antioxidantes/química , Staphylococcus aureus , Hipoglicemiantes/farmacologia , Nanopartículas Metálicas/química , Escherichia coli , Extratos Vegetais/química , Anti-Infecciosos/química , Espectrometria por Raios X , Polissacarídeos/farmacologia , Antibacterianos/farmacologia
2.
CNS Neurosci Ther ; 28(11): 1779-1789, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35822697

RESUMO

INTRODUCTION: Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a relatively common cerebral small vessel disease. NOTCH3 has been identified as the causative gene of CADASIL. Clinical variability and genetic heterogeneity were observed in CADASIL patients and need to be further clarified. AIMS: The aim of the study was to clarify genetic spectrum of NOTCH3 and clinical phenotype of CADASIL patients. METHODS: Suspected CADASIL patients were collected by our center between 2016 and 2021. Whole exome sequencing was performed to screen NOTCH3 mutations of these patients. Genetic and clinical data of CADASIL patients from previous studies were also analyzed. Studies between 1998 and 2021 that reported more than 9 pedigrees with detailed genetic data or clinical data were included. After excluding patients carrying cysteine-sparing mutations, genetic data of 855 Asian pedigrees (433 Chinese; 226 Japanese, and 196 Korean) and 546 Caucasian pedigrees, in a total of 1401 CADASIL pedigrees were involved in mapping mutation spectrum. Clinical data of 901 Asian patients (476 Chinese patients, 217 Japanese patients, and 208 Korean patients) and 720 Caucasian patients, in a total of 1621 patients were analyzed and compared between different populations. RESULTS: Two novel mutations (c.400T>C, p.Cys134Arg; c.1511G>A, p.Cys504Tyr) and 24 known cysteine-affecting variants were identified in 36 pedigrees. Genetic spectrums of Asians (Chinese, Japanese, and Korean) and Caucasians were clarified, p.R544C and p.R607C were the most common mutations in Asians while p.R1006C and p.R141C in Caucasians. For clinical features, Asians were more likely to develop symptoms of TIA or ischemic stroke (p < 0.0001) and cognitive impairment (p < 0.0001). Nevertheless, Caucasians had a higher tendency to present migraine (p < 0.0001) and psychiatric disturbance (p < 0.0001). The involvement of temporal pole was more likely to happen in Caucasians (p < 0.0001). CONCLUSION: The findings help to better understand the clinical variability and genetic heterogeneity of CADASIL.


Assuntos
CADASIL , CADASIL/genética , Cisteína/genética , Humanos , Imageamento por Ressonância Magnética , Mutação/genética , Fenótipo , Receptor Notch3/genética , Receptores Notch/genética
4.
Cancer Manag Res ; 10: 4959-4967, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30464596

RESUMO

INTRODUCTION: The association of single-nucleotide polymorphisms at X-ray repair cross-complementing group-1 (XRCC1) with osteosarcoma (OS) development has not been fully clear to date. The aim of the present study is to evaluate the association of XRCC1 polymorphisms with risk, clinicopathologic features, and prognosis in Chinese OS patients. METHODS: A total of 146 patients with primary OS and 248 age- and gender-matched controls were included in the present study. The frequencies of four XRCC1 polymorphisms (rs25487, rs1799782, rs25489, and rs3213245) were determined between OS patients and controls. The association of XRCC1 polymorphism with clinicopathologic characteristics, prognosis, and XRCC1 expression was further evaluated. RESULTS: Compared with TT genotype, individuals carrying the minor C allele (TC+ CC) of rs3213245 had significantly increased risk of OS development (OR =1.83, 95% CI 1.14-3.00). OS patients carrying TC genotype and C allele at rs3213245 were more likely to be with larger tumor size and metastasis. Survival analysis demonstrated that OS patients carrying C allele (TC + CC) at rs3213245 had shorter survival time than those with TT genotype. The T to C substitution at rs3213245 could decrease XRCC1 gene transcriptional activity in vitro. XRCC1 mRNA and protein expression levels were lower in OS patients carrying TC or CC genotype at rs3213245. Besides, no significant association of rs25487, rs1799782, and rs25489 with OS was observed. CONCLUSION: In conclusion, these findings revealed that XRCC1 rs3213245 polymorphism was associated with increased risk of OS, which could affect XRCC1 expression in vitro and in vivo.

5.
Med Sci Monit ; 24: 235-245, 2018 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-29326419

RESUMO

BACKGROUND This study aimed to investigate the predictive value of multislice spiral computed tomography (MSCT) perfusion imaging for the efficacy of preoperative concurrent chemoradiotherapy (CCRT) in middle-aged and elderly patients with locally advanced gastric cancer (LAGC). MATERIAL AND METHODS One-hundred twenty-six middle-aged and elderly patients with LAGC were selected. MSCT was performed before and after CCRT to obtain perfusion parameters: blood flow volume (BF), blood volume (BV), mean transit time (MTT), and permeability surface (PS). After CCRT, according to Response Evaluation Criteria in Solid Tumors (RECIST), patients were categorized into the effective group and the ineffective group. Overall survival rate was measured by Kaplan-Meier analysis. ROC curve was applied to evaluate the predictive value of perfusion parameters. Multiple logistic regression analysis was applied to analyze the association of perfusion parameters with the efficacy of preoperative treatment. RESULTS Tumor volume reduction rates of the effective and ineffective groups were 59.23±8.53% and 10.41±3.36%. BF, BV, and PS values in the effective group were significantly decreased after CCRT. ROC curves indicated high sensitivities and specificities of BF value (79.00%, 73.44%), BV value (71.00%, 75.00%), and PS value (82.30%, 90.63%). The incidence rate of weakness and anorexia in the effective group was much higher than that in the ineffective group. Patients with low BF, BV, and PS values (less their optimal cutoff values) had longer survival times than these with high BF, BV, and PS values. CONCLUSIONS MSCT might have predictive values for the efficacy of preoperative CCRT in the treatment of LAGC.


Assuntos
Quimiorradioterapia , Imagem de Perfusão , Cuidados Pré-Operatórios , Neoplasias Gástricas/diagnóstico por imagem , Neoplasias Gástricas/terapia , Tomografia Computadorizada Espiral , Idoso , Idoso de 80 Anos ou mais , Quimiorradioterapia/efeitos adversos , Feminino , Humanos , Estimativa de Kaplan-Meier , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Valor Preditivo dos Testes , Curva ROC , Neoplasias Gástricas/patologia , Neoplasias Gástricas/cirurgia , Resultado do Tratamento
6.
CNS Neurosci Ther ; 23(9): 707-716, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28710804

RESUMO

AIM: To characterize clinical features and mutation spectrum in Chinese patients with CADASIL. METHODS: We collected 261 clinically suspected Chinese CADASIL patients from three hospitals located in different regions of China. Sanger sequencing is performed to screen the exons 2 to 24 of NOTCH3 gene. Clinical and genetic data were retrospectively studied. Haplotype analyses were performed in patients carrying p.Arg544Cys and p.Arg607Cys, respectively. RESULTS: A total of 214 patients were finally genetically diagnosed as CADASIL, with 45 known NOTCH3 mutations and a novel c.1817G>T mutation. We found that patients carrying p.Arg607Cys or p.Arg544Cys mutation located in exon 11 occupied nearly 35% in our mutation spectrum. In retrospectively study of clinical data, we found a higher number of patients having cognitive impairment and a lower number of patients having migraine with aura. Furthermore, we identified that patients carrying mutations in exon 11 seemed to experience a later disease onset (p=6.8×10-5 ). Additionally, a common haplotype was found in patients from eastern China carrying p.Arg607Cys, and the patients from Fujian carrying p.Arg544Cys shared the same haplotype with patients from Taiwan carrying p.Arg544Cys. CONCLUSIONS: These findings broaden the mutational and clinical spectrum of CADASIL and provide additional evidences for the existence of founder effect in CADASIL patients.


Assuntos
CADASIL/genética , Mutação/genética , Receptor Notch3/genética , Adulto , Idade de Início , Arginina/genética , Povo Asiático/genética , CADASIL/fisiopatologia , Cisteína/genética , Éxons/genética , Feminino , Estudos de Associação Genética , Células HEK293 , Haplótipos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Transfecção
7.
Abdom Radiol (NY) ; 42(11): 2745-2751, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28477177

RESUMO

PURPOSE: To determine the clinical efficiency and long-term outcomes between unilateral and bilateral stent insertion in patients with malignant hilar biliary obstruction. METHODS: From August 2012 to February 2016, 63 consecutive patients with malignant hilar biliary obstruction were treated with unilateral or bilateral stent insertion at our center. The bilateral stents were inserted using the side-by-side technique. The clinical efficiency and long-term outcomes were compared between the two groups. RESULTS: Unilateral and bilateral stent insertions were successfully performed in 31 of 33 and 27 of 30 patients, respectively (P = 0.912). No procedure-related complication occurred. Clinical success was achieved in 29 of 31 patients in the unilateral stent group and in 26 of 27 patients in the bilateral stent group (P = 0.637). During the follow-up, re-obstruction of stent occurred in five patients in the unilateral stent group and in three patients in the bilateral stent group (P = 0.58). The significant differences were not observed in the stent patency time (368 vs. 387 days, P = 0.685) and survival (200 vs. 198 days, P = 0.751) between two groups. Based on the univariate and multivariate analyses, the independent risk factors for decreasing the survival time included higher Eastern Cooperative Oncology Group performance status (P = 0.018), higher alanine aminotransferase level (P = 0.009), and absence of anticancer treatment after stent insertion (P = 0.002). CONCLUSION: Compared to bilateral stent insertion for malignant hilar biliary obstruction, unilateral stent insertion can provide comparable clinical efficiency and long-term outcomes.


Assuntos
Neoplasias dos Ductos Biliares/cirurgia , Colestase/cirurgia , Stents , Idoso , Ductos Biliares Intra-Hepáticos , Colangiografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Radiografia Intervencionista , Estudos Retrospectivos , Resultado do Tratamento , Ultrassonografia de Intervenção
8.
Biomed Rep ; 5(2): 217-220, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27446545

RESUMO

Pantothenate kinase-associated neurodegeneration (PKAN) is a rare autosomal recessive neurodegenerative disorder resulting from pantothenate kinase 2 (PANK2) gene mutations. It is clinically characterized by early onset of extrapyramidal symptoms, with or without pigmentary retinopathy, optic atrophy and acanthocytosis. The specific radiographic appearance of PKAN is the eye-of-the-tiger sign. However, there are few studies regarding PKAN patients of Chinese Han ancestry. In the present study, a Chinese 20-year-old female with an 8-year history of unsteady walking and involuntary movements is described. Brain magnetic resonance imaging revealed eye-of-the-tiger sign. Following sequencing of PANK2, a novel homozygous c.863C>T (p.P288L) mutation was identified in the patient and heterozygous c.863C>T was identified in her consanguineous parents. The absence of this mutation in the 1000 Genomes database, The Exome Aggregation Consortium, and 200 controls demonstrated that this mutation was probably pathogenic for PKAN in this family. In addition, the PANK2 c.863C>T mutation was predicted to be deleterious by SIFT, disease causing by Mutation Taster and probably damaging by PolyPhen2.

9.
Chin Med J (Engl) ; 129(9): 1017-21, 2016 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-27098784

RESUMO

BACKGROUND: Paroxysmal kinesigenic dyskinesia (PKD) is the most common subtype of paroxysmal dyskinesias and is caused by mutations in PRRT2 gene. The majority of familial PKD was identified to harbor PRRT2 mutations. However, over two-third of sporadic PKD patients did not carry anyPRRT2 mutation, suggesting an existence of additional genetic mutations or possible misdiagnosis due to clinical overlap. METHODS: A cohort of 28 Chinese patients clinically diagnosed with sporadic PKD and excluded PRRT2 mutations were recruited. Clinical features were evaluated, and all subjects were screened for MR-1, SLC2A1, and CLCN1 genes, which are the causative genes of paroxysmal nonkinesigenic dyskinesia (PNKD), paroxysmal exertion-induced dyskinesia, and myotonia congenita (MC), respectively. In addition, 200 genetically matched healthy individuals were recruited as controls. RESULTS: A total of 16 genetic variants including 4 in MR-1 gene, 8 in SLC2A1 gene, and 4 in CLCN1 gene were detected. Among them, SLC2A1 c.363G>A mutation was detected in one case, and CLCN1 c.1205C>T mutation was detected in other two cases. Neither of them was found in 200 controls as well as 1000 Genomes database and ExAC database. Both mutations were predicted to be pathogenic by SIFT and PolyPhen2. The SLC2A1 c.363G>A mutation was novel. CONCLUSIONS: The phenotypic overlap may lead to the difficulty in distinguishing PKD from PNKD and MC. For those PRRT2- negative PKD cases, screening of SLC2A1 and CLCN1 genes are useful in confirming the diagnosis.


Assuntos
Canais de Cloreto/genética , Distonia/genética , Transportador de Glucose Tipo 1/genética , Proteínas de Membrana/genética , Proteínas Musculares/genética , Mutação , Proteínas do Tecido Nervoso/genética , Adolescente , Adulto , Criança , Coreia/genética , Distonia/diagnóstico , Feminino , Humanos , Masculino , Miotonia Congênita/genética
10.
Biol Open ; 4(12): 1744-52, 2015 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-26621826

RESUMO

Paroxysmal kinesigenic dyskinesia (PKD) is a monogenic movement disorder with autosomal dominant inheritance. We previously identified the proline-rich transmembrane protein 2 (PRRT2) as a causative gene of PKD. However, the pathogenesis of PKD remains largely unknown so far. In addition, applicable modeling tools to investigate the underlying mechanisms of PKD are still lacking. The combination of disease-specific human induced pluripotent stem cells (iPSCs) and directed cell differentiation offers an ideal platform for disease modeling. In this study, we generated two iPSC lines from the renal epithelial cells of one PKD patient with the hotspot c.649dupC mutation (PKD-iPSCs). These cell lines were positive for alkaline phosphatase Nanog, Tra-1-80, Tra-1-60, SSEA-3 and SSEA-4. Teratomas with three blastoderms including ectoderm, mesoderm, and endoderm were obtained two months after injection of PKD-iPSCs into NOD/SCID mice. The expression of PRRT2 mRNA was decreased in PKD-iPSCs compared with that of the control iPSCs. Furthermore, PKD-iPSCs possessed the differentiation potential of functional glutamatergic, dopaminergic and motor neurons in vitro. Electrophysiological examinations revealed that the current densities of fast activated and deactivated sodium channels as well as voltage gated potassium channels were not different between the neurons from PKD-iPSCs and control iPSCs. Thus, PKD-iPSCs are a feasible modeling tool to investigate the pathogenic mechanisms of PKD.

11.
CNS Neurosci Ther ; 21(8): 626-30, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26096180

RESUMO

AIMS: Recently, mutations in COQ2 encoding para-hydroxybenzoate-polyprenyl transferase have been identified to increase the risk of multiple system atrophy (MSA) in multiplex families and sporadic cases. The prevalence of COQ2 mutations was showed to be higher in cerebellar subtype (MSA-C) than parkinsonism subtype (MSA-P). The aim of this study was to investigate the association between COQ2 mutations and MSA-C in Chinese patients. METHODS: A Chinese cohort of 116 patients with MSA-C and 192 healthy control individuals were recruited. Sanger sequencing of COQ2 was performed in all these subjects. RESULTS: Two missense mutations (p.L402F and p.R173H) and one synonymous mutation (p.A32A) were detected in 3 patients, respectively. They were not found in the 192 controls as well as the 1000 Genomes Database. The p.L402F and p.A32A were novel. CONCLUSION: Our results indicated that COQ2 tended to play a population-specific and subtype-depended role in conferring susceptibility to MSA.


Assuntos
Alquil e Aril Transferases/genética , Atrofia de Múltiplos Sistemas/genética , Mutação , Povo Asiático/genética , Encéfalo/patologia , China , Estudos de Coortes , Análise Mutacional de DNA , Bases de Dados Genéticas , Feminino , Predisposição Genética para Doença , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Atrofia de Múltiplos Sistemas/patologia , Atrofia de Múltiplos Sistemas/fisiopatologia
12.
Neurobiol Aging ; 36(3): 1603.e11-4, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25457026

RESUMO

An effective treatment for amyotrophic lateral sclerosis (ALS) has not yet been found because the pathogenesis of this fatal disease is not well understood. A number of previous studies demonstrated that intermediate-length polyglutamine repeats within the ataxin-2 gene (ATXN2) might be a risk factor among patients with ALS in Western countries. Here, we aim to determine whether this sequence is a risk factor in Eastern Chinese ALS patients. Therefore, 379 unrelated sporadic ALS patients, 15 unrelated familial ALS patients, and 900 neurologically normal controls were studied. The ATXN2 CAG repeats were amplified using polymerase chain reaction. The products were separated on an 8% polyacrylamide gel and confirmed using Sanger sequencing. The results were evaluated using SPSS 17.0. We found that ATXN2 intermediate-length polyglutamine expansions greater than 24 and 27 repeats were associated with sporadic ALS. Our finding supports the hypothesis that ATXN2 plays an important role in the pathogenesis of ALS.


Assuntos
Esclerose Lateral Amiotrófica/genética , Ataxina-2/genética , Estudos de Associação Genética , Predisposição Genética para Doença/genética , Peptídeos/genética , Expansão das Repetições de Trinucleotídeos , Adolescente , Adulto , Idoso , Povo Asiático/genética , Ataxina-2/química , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Adulto Jovem
13.
Nat Prod Res ; 27(23): 2251-5, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23962054

RESUMO

(-)-Arctigenin, an important active constituent of the traditional Chinese herb Fructus Arctii, was found to exhibit various bioactivities, so it can be used as a good lead compound for further structure modification in order to find a safer and more potent medicine. (-)-Arctigenin derivatives 1-5 of (-)-arctingen were obtained by modifying with ammonolysis at the lactone ring and sulphonylation at C (6') and C (6″) and O-demethylation at CH3O-C (3'), CH3O-C (3″) and CH3O-C (4″), and their anticancer bioactivities were examined.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Furanos/farmacologia , Lignanas/farmacologia , Antineoplásicos Fitogênicos/química , Linhagem Celular Tumoral , Descoberta de Drogas , Furanos/química , Humanos , Lignanas/química , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Estrutura Molecular
14.
Gene ; 529(1): 159-62, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-23939468

RESUMO

Idiopathic basal ganglia calcification (IBGC) is a rare neuropsychiatric disorder characterized by bilateral and symmetric cerebral calcifications. Recently, SLC20A2 was identified as a causative gene for familial IBGC, and three mutations were reported in a northern Chinese population. Here, we aimed to explore the mutation spectrum of SLC20A2 in a southern Chinese population. Sanger sequencing was employed to screen mutations within SLC20A2 in two IBGC families and 14 sporadic IBGC cases from a southern Han Chinese population. Four novel mutations (c.82G>A p.D28N, c.185T>C p.L62P, c.1470_1478delGCAGGTCCT p.Q491_L493del and c.935-1G>A) were identified in two families and two sporadic cases, respectively; none were detected in 200 unrelated controls. No mutation was found in the remaining 12 patients. Different mutations may result in varied phenotypes, including brain calcification and clinical manifestations. Our study supports the hypothesis that SLC20A2 is a causative gene of IBGC and expands the mutation spectrum of SLC20A2, which facilitates the understanding of the genotype-phenotype correlation of IBGC.


Assuntos
Povo Asiático/genética , Doenças dos Gânglios da Base/genética , Calcinose/genética , Doenças Neurodegenerativas/genética , Proteínas Cotransportadoras de Sódio-Fosfato Tipo III/genética , Adulto , Idoso , Gânglios da Base/patologia , Doenças dos Gânglios da Base/patologia , Calcinose/patologia , Criança , Pré-Escolar , China , Éxons , Feminino , Estudo de Associação Genômica Ampla , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Doenças Neurodegenerativas/patologia , Linhagem , Análise de Sequência de DNA , Adulto Jovem
15.
Neurosci Lett ; 432(2): 83-7, 2008 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-18243549

RESUMO

Production of reactive oxygen species (ROS) results in up-regulation of the extracellular signal-regulated kinase (ERK) cascade in response to numerous stimuli. Cerebral ischemia induces calcium-dependent kinase activation followed by ROS production. Here, we examined how ROS mediates the activation of ERK following cerebral ischemia in the rat hippocampus. We found that alpha-tocopherol, a free radical scavenger, attenuated the initial, robust activation of ERK by inhibiting Raf-1 dephosphorylation at Ser259. Alpha-tocopherol also down-regulated the second and mild activation of ERK through inhibition of Src-dependent phosphorylation of Raf-1 at Tyr340/341. Our results suggest that ROS production mediates the biphasic activation of ERK through different signaling cascades following post-ischemic reperfusion. Mediation of these signaling pathways involves changes in Raf-1 phosphorylation at different sites.


Assuntos
Isquemia Encefálica/enzimologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Estresse Oxidativo/fisiologia , Proteínas Proto-Oncogênicas c-raf/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/fisiologia , Animais , Encéfalo/enzimologia , Encéfalo/fisiopatologia , Isquemia Encefálica/fisiopatologia , Domínio Catalítico/efeitos dos fármacos , Domínio Catalítico/fisiologia , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/fisiologia , Sequestradores de Radicais Livres/farmacologia , Masculino , Estresse Oxidativo/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Traumatismo por Reperfusão/enzimologia , Traumatismo por Reperfusão/fisiopatologia , Transdução de Sinais/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/fisiologia , alfa-Tocoferol/farmacologia , Quinases da Família src/metabolismo
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