RESUMO
The present study focuses on the neuroprotective effect of glycyrrhizic acid (GA, a major compound separated from Glycyrrhiza Radix, which is a crude Chinese traditional drug) against glutamate-induced cytotoxicity in differentiated PC12 (DPC12) cells. The results showed that GA treatment improved cell viability and ameliorated abnormal glutamate-induced alterations in mitochondria in DPC12 cells. GA reversed glutamate-suppressed B-cell lymphoma 2 levels, inhibited glutamate-enhanced expressions of Bax and cleaved caspase 3, and reduced cytochrome C (Cyto C) release. Exposure to glutamate strongly inhibited phosphorylation of AKT (protein kinase B) and extracellular signal-regulated kinases (ERKs); however, GA pretreatment enhanced activation of ERKs but not AKT. The presence of PD98059 (a mitogen-activated protein/extracellular signal-regulated kinase kinase [MEK] inhibitor) but not LY294002 (a phosphoinositide 3-kinase [PI3K] inhibitor) diminished the potency of GA for improving viability of glutamate-exposed DPC12 cells. These results indicated that ERKs and mitochondria-related pathways are essential for the neuroprotective effect of GA against glutamate-induced toxicity in DPC12 cells. The present study provides experimental evidence supporting GA as a potential therapeutic agent for use in the treatment of neurodegenerative diseases.
Assuntos
Animais , Ratos , Anti-Inflamatórios/uso terapêutico , Ácido Glutâmico/toxicidade , Ácido Glicirrízico/uso terapêutico , Fármacos Neuroprotetores/uso terapêutico , /efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Apoptose/efeitos dos fármacos , /isolamento & purificação , Diferenciação Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cromonas/farmacologia , Citocromos c/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Flavonoides/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Morfolinas/farmacologia , /classificação , /citologia , Proteínas Proto-Oncogênicas c-akt/efeitos dos fármacos , /isolamento & purificação , /isolamento & purificaçãoRESUMO
The present study focuses on the neuroprotective effect of glycyrrhizic acid (GA, a major compound separated from Glycyrrhiza Radix, which is a crude Chinese traditional drug) against glutamate-induced cytotoxicity in differentiated PC12 (DPC12) cells. The results showed that GA treatment improved cell viability and ameliorated abnormal glutamate-induced alterations in mitochondria in DPC12 cells. GA reversed glutamate-suppressed B-cell lymphoma 2 levels, inhibited glutamate-enhanced expressions of Bax and cleaved caspase 3, and reduced cytochrome C (Cyto C) release. Exposure to glutamate strongly inhibited phosphorylation of AKT (protein kinase B) and extracellular signal-regulated kinases (ERKs); however, GA pretreatment enhanced activation of ERKs but not AKT. The presence of PD98059 (a mitogen-activated protein/extracellular signal-regulated kinase kinase [MEK] inhibitor) but not LY294002 (a phosphoinositide 3-kinase [PI3K] inhibitor) diminished the potency of GA for improving viability of glutamate-exposed DPC12 cells. These results indicated that ERKs and mitochondria-related pathways are essential for the neuroprotective effect of GA against glutamate-induced toxicity in DPC12 cells. The present study provides experimental evidence supporting GA as a potential therapeutic agent for use in the treatment of neurodegenerative diseases.
Assuntos
Anti-Inflamatórios/uso terapêutico , Ácido Glutâmico/toxicidade , Ácido Glicirrízico/uso terapêutico , Fármacos Neuroprotetores/uso terapêutico , Células PC12/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Caspase 3/isolamento & purificação , Diferenciação Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cromonas/farmacologia , Citocromos c/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Flavonoides/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Morfolinas/farmacologia , Células PC12/classificação , Células PC12/citologia , Proteínas Proto-Oncogênicas c-akt/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-bcl-2/isolamento & purificação , Ratos , Proteína X Associada a bcl-2/isolamento & purificaçãoRESUMO
Amyloid deposits consist of protein fibrils and amorphous material, and this deposition is related to oxidative stress. Previously, we demonstrated the presence of high-density lipoproteins and/or lipids in amyloid deposits of familial amyloid polyneuropathy patients. In this study, the presence of myeloperoxidase (MPO) in amyloid deposits was demonstrated using immunohistochemical staining. In contrast, normal surrounding tissues were consistently negative for MPO. Nitrotyrosine was present in amyloid deposits after being exposed to the MPO/H2O2/NO(-) system by immunohistochemical staining, and the oxide mediated modification of serum transthyretin (TTR) was observed upon exposure to the MPO/H2O2 system using two-dimensional gel electrophoresis and TTR Western blotting. This observation revealed that the TTR amyloid deposits and serum TTR were oxidized by the MPO/H2O2/NO(-) system. Nitric oxide-mediated modification of TTR may play a role in amyloidogenesis in vivo.
Assuntos
Neuropatias Amiloides Familiares/sangue , Óxido Nítrico/sangue , Pré-Albumina/metabolismo , Adulto , Amiloide/sangue , Neuropatias Amiloides Familiares/patologia , Feminino , Humanos , Peróxido de Hidrogênio/metabolismo , Lipoproteínas HDL/sangue , Pessoa de Meia-Idade , Mutação , Peroxidase/sangue , Tirosina/análogos & derivados , Tirosina/sangue , Tirosina/metabolismoRESUMO
To find Epstein-Barr virus (EBV) strains with genetic variations of EBV latent membrane protein 1 (EBV-LMP1) from nasopharyngeal carcinoma (NPC), the full-length DNA of LMP1 genes from 21 NPC biopsies obtained in Hunan province in southern China was amplified and sequenced. Our sequences were compared to those previously reported by the Clustal V method. Results showed that all 21 sequences displayed two amino acid changes most frequently in LMP1 of CD4+ T cell epitopes at codons 144 (F-->I, 21/21) and 212 (G-->S, 19/21) or (G-->N, 2/21). We also show that type A EBV strain is prevalent in the cases of NPC from Hunan province with a 30-bp 18/21 deletion, and we highlight that this deletion resulted in loss of one of the CD4+ T cell-restricted epitopes. The other 3 sequences without this deletion all had a change at codon 344 (G-->D). Furthermore, in the major epitope sequence of CD8+ T cells restricted by HLA-A2, all 21 sequences showed changes at codons 126 (L-->F) and 129 (M-->I). Our study discovered that one of the 21 sequence variations harbored a new change at codon 131 (W-->C), and 5/21 specimens showed another novel change at codon 115 (G-->A) in the major epitope sequence of CD8+ T cells restricted by HLA-A2. Our study suggests that these sequence variations of NPC-derived LMP1 may lead to a potential escape from host cell immune recognition, protecting latent EBV infection and causing an increase in tumorigenicity.
Assuntos
Epitopos de Linfócito T/genética , Variação Genética , Antígeno HLA-A2/genética , Neoplasias Nasofaríngeas/virologia , Proteínas da Matriz Viral/genética , Adulto , Sequência de Aminoácidos , Biópsia , Linfócitos T CD4-Positivos , Linfócitos T CD8-Positivos , Epitopos de Linfócito T/análise , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Análise de Sequência de DNARESUMO
To find Epstein-Barr virus (EBV) strains with genetic variations of EBV latent membrane protein 1 (EBV-LMP1) from nasopharyngeal carcinoma (NPC), the full-length DNA of LMP1 genes from 21 NPC biopsies obtained in Hunan province in southern China was amplified and sequenced. Our sequences were compared to those previously reported by the Clustal V method. Results showed that all 21 sequences displayed two amino acid changes most frequently in LMP1 of CD4+ T cell epitopes at codons 144 (F arrow right I, 21/21) and 212 (G arrow right S, 19/21) or (G arrow right N, 2/21). We also show that type A EBV strain is prevalent in the cases of NPC from Hunan province with a 30-bp 18/21 deletion, and we highlight that this deletion resulted in loss of one of the CD4+ T cell-restricted epitopes. The other 3 sequences without this deletion all had a change at codon 344 (G arrow right D). Furthermore, in the major epitope sequence of CD8+ T cells restricted by HLA-A2, all 21 sequences showed changes at codons 126 (L arrow right F) and 129 (M arrow right I). Our study discovered that one of the 21 sequence variations harbored a new change at codon 131 (W arrow right C), and 5/21 specimens showed another novel change at codon 115 (G arrow right A) in the major epitope sequence of CD8+ T cells restricted by HLA-A2. Our study suggests that these sequence variations of NPC-derived LMP1 may lead to a potential escape from host cell immune recognition, protecting latent EBV infection and causing an increase in tumorigenicity.