RESUMO
We have found that Fas/FasL-mediated "extrinsic" pathway promoted cell apoptosis induced by renal ischemic injury. This study is to elucidate the upstream mechanism regulating FasL-induced extrinsic pathway during renal ischemia/reperfusion. Results demonstrated that when SIRT2 was activated by renal ischemia/reperfusion, activated SIRT2 could bind to and deacetylate FOXO3a, promoting FOXO3a nuclear translocation which resulted in an increase of nuclear FOXO3a along with FasL expression and activation of caspase8 and caspase3, triggering cell apoptosis during renal ischemia/reperfusion. The administration of SIRT2 inhibitor AGK2 prior to renal ischemia decreased significantly the number of apoptotic renal tubular cells and alleviated ultrastructure injury. These results indicate that inhibition of FOXO3a deacetylation might be a promising therapeutic approach for renal ischemia /reperfusion injury.
Assuntos
Transporte Ativo do Núcleo Celular/fisiologia , Apoptose/fisiologia , Proteína Ligante Fas/fisiologia , Proteína Forkhead Box O3/metabolismo , Isquemia/patologia , Rim/irrigação sanguínea , Traumatismo por Reperfusão/patologia , Sirtuína 2/fisiologia , Acetilação , Animais , Núcleo Celular/metabolismo , Avaliação Pré-Clínica de Medicamentos , Ativação Enzimática , Furanos/farmacologia , Isquemia/metabolismo , Rim/patologia , Masculino , Processamento de Proteína Pós-Traducional , Quinolinas/farmacologia , Ratos , Ratos Sprague-Dawley , Traumatismo por Reperfusão/metabolismoRESUMO
Previous studies have reported that selenite, a known antioxidant, protects brain against ischemia/reperfusion injury, which is mediated by oxidative stress. The aim of this study was to investigate whether selenite can protect kidney against ischemic injury by reducing activation of the apoptosis signal regulating kinase 1 (ASK1)/mitogen-activated protein kinase kinase 3 (MKK3)/p38 mitogen-activated protein kinase signaling pathway. The activation and expression of ASK1, MKK3, p38, caspase 3 and cleaved PARP were analyzed by Western blot. Apoptosis of renal tubular epithelial cells was assessed by the terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling method. Malondialdehyde (MDA) levels were measured by the thiobarbituric acid reaction. Blood serum creatinine and blood urea nitrogen level were measured with an Olympus automatic multi-analyzer. We found that selenite attenuated significantly ASK1, MKK3, and p38 phosphorylation at 3 h after renal ischemia. Furthermore, selenite decreased significantly renal epithelial tubular cell apoptosis. In addition, selenite reduced the MDA level. These findings suggest that the protective action of selenite on ischemia renal injury is associated closely with reducing activation of the ASK1-MKK3-p38 signal pathway.
Assuntos
Rim/efeitos dos fármacos , MAP Quinase Quinase 3/antagonistas & inibidores , MAP Quinase Quinase Quinase 5/antagonistas & inibidores , Traumatismo por Reperfusão/tratamento farmacológico , Transdução de Sinais/efeitos dos fármacos , Selenito de Sódio/uso terapêutico , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidores , Animais , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Apoptose/fisiologia , Caspase 3/metabolismo , Ativação Enzimática , Humanos , Rim/metabolismo , Rim/patologia , Peroxidação de Lipídeos/efeitos dos fármacos , MAP Quinase Quinase 3/metabolismo , MAP Quinase Quinase Quinase 5/metabolismo , Masculino , Poli(ADP-Ribose) Polimerases/metabolismo , Ratos , Ratos Sprague-Dawley , Traumatismo por Reperfusão/metabolismo , Traumatismo por Reperfusão/patologia , Transdução de Sinais/fisiologia , Selenito de Sódio/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
A new standardized Ginkgo extract (ginaton) destined for i.v. injection was investigated in rats for its protective effect on renal ischemia/reperfusion injury. We report on the elucidation of the downstream mechanism of action of JNK on the renal ischemia/reperfusion injury, which can be explained as the decrease in JNK phosphorylation at 20 min and c-Jun phosphorylation (Ser63/73) at 3h after renal ischemia. At the same time, ginaton attenuated the increased expression of FasL at 3h and caspase3 immunoreactivity at 6h after renal ischemia. Furthermore, ginaton significantly decreased renal epithelial tubular cell apoptosis induced by renal ischemia/reperfusion, alleviating renal ischemia/reperfusion injury. These results cumulatively indicate that ginaton could suppress the JNK-c-Jun-FasL-caspase3 signaling cascade, protecting renal tubular epithelial cells against ischemia/reperfusion-induced apoptosis, which implies that antioxidants may be a potential and effective agent for prevention of the ischemic/reperfusion injury through the suppression extrinsic apoptotic signal pathway induced by JNK signal pathway.
Assuntos
Medicamentos de Ervas Chinesas/farmacologia , Rim/irrigação sanguínea , Substâncias Protetoras/farmacologia , Traumatismo por Reperfusão/prevenção & controle , Animais , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Relação Dose-Resposta a Droga , Proteína Ligante Fas/metabolismo , Ginkgo biloba , Isquemia/fisiopatologia , Isquemia/terapia , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Rim/patologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Ratos , Ratos Sprague-DawleyRESUMO
Accumulating evidence suggests that c-Jun N-terminal kinase (JNK) signaling pathway plays a critical role in renal ischemia/reperfusion injury. However, the downstream mechanism that accounts for the proapoptotic actions of JNK during renal ischemia/reperfusion has not been elucidated. We report that SP600125, a potent, cell-permeable, selective, and reversible inhibitor of c-Jun N-terminal kinase (JNK), potently decreased renal epithelial tubular cell apoptosis induced by renal ischemia/reperfusion via suppression of the extrinsic pathway. This corresponds to the decrease in JNK phosphorylation at 20 min and c-Jun phosphorylation (Ser63/73) at 3 h after renal ischemia. Additionally, SP600125 attenuated the increased expression of FasL induced by ischemia/reperfusion at 3 h. The administration of SP600125 prior to ischemia was also protective. Thus, our findings imply that SP600125 can inhibit the activation of the JNK-c-Jun-FasL pathway and protect renal tubular epithelial cells against ischemia/reperfusion-induced apoptosis. Taken together, these results indicate that targeting the JNK pathway provides a promising therapeutic approach for renal ischemia/reperfusion injury.