RESUMO
Hyperglycemia results in the formation of reactive oxygen species which in turn causes advanced glycation end products (AGEs) formation, leading to diabetic cardiomyopathy. Our previous study showed that AGE-induced reactive oxygen species-dependent apoptosis is mediated via protein kinase C delta (PKCδ)-enhanced mitochondrial damage in cardiomyocytes. By using microRNA (miRNA) database, miRNA-210 was predicted to target c-Jun N-terminal kinase (JNK), which were previously identified as downstream of PKCδ in regulating mitochondrial function. Therefore, we hypothesized that miR-210 mediates PKCδ-dependent upregulation of JNK to cause cardiac mitochondrial damage and apoptosis following AGE exposure. AGE-exposed cells showed activated cardiac JNK, PKCδ, and apoptosis, which were reversed by treatment with a JNK inhibitor and PKCδ-KD (deficient kinase). Cardiac miR-210 and mitochondrial function were downregulated following AGE exposure. Furthermore, JNK was upregulated and involved in AGE-induced mitochondrial damage. Interestingly, luciferase activity of the miR-210 mimic plus JNK WT-3'-untranslated region overexpressed group was significantly lower than that of miR-210 mimic plus JNK MT-3'UTR group, indicating that JNK is a target of miR-210. Moreover, JNK activation induced by AGEs was reduced by treatment with the miR-210 mimic and reversed by treatment with the miR-210 inhibitor, indicating the regulatory function of miR-210 in JNK activation following AGE exposure. Additionally, JNK-dependent mitochondrial dysfunction and apoptosis were reversed following treatment with the miR-210 mimic, while the miR-210 inhibitor showed no effect on JNK-induced mitochondrial dysfunction and apoptosis in AGE-exposed cardiac cells. Taken together, our study showed that PKCδ-enhanced JNK-dependent mitochondrial damage is mediated through the reduction of miR-210 in cardiomyocytes following AGE exposure.
Assuntos
Apoptose , Produtos Finais de Glicação Avançada/metabolismo , MAP Quinase Quinase 4/metabolismo , MicroRNAs/metabolismo , Mitocôndrias Cardíacas/metabolismo , Animais , Linhagem Celular , Produtos Finais de Glicação Avançada/genética , MAP Quinase Quinase 4/genética , MicroRNAs/genética , Mitocôndrias Cardíacas/genética , RatosRESUMO
Chronic high-glucose exposure results in the production of advanced glycation end-products (AGEs) leading to reactive oxygen species (ROS) generation, which contributes to the development of diabetic cardiomyopathy. PKCδ activation leading to ROS production and mitochondrial dysfunction involved in AGE-induced cardiomyocyte apoptosis was reported in our previous study. Diallyl trisulfide (DATS) is a natural cytoprotective compound under various stress conditions. In this study, the cardioprotective effect of DATS against rat streptozotocin (STZ)-induced diabetic mellitus (DM) and AGE-induced H9c2 cardiomyoblast cell/neonatal rat ventricular myocyte (NRVM) damage was assessed. We observed that DATS treatment led to a dose-dependent increase in cell viability and decreased levels of ROS, inhibition of PKCδ activation, and recuded apoptosis-related proteins. Most importantly, DATS reduced PKCδ mitochondrial translocation induced by AGE. However, apoptosis was not inhibited by DATS in cells transfected with PKCδ-wild type (WT). Inhibition of PKCδ by PKCδ-kinase-deficient (KD) or rottlerin not only inhibited cardiac PKCδ activation but also attenuated cardiac cell apoptosis. Interestingly, overexpression of PKCδ-WT plasmids reversed the inhibitory effects of DATS on PKCδ activation and apoptosis in cardiac cells exposed to AGE, indicating that DATS may inhibit AGE-induced apoptosis by downregulating PKCδ activation. Similar results were observed in AGE-induced NRVM cells and STZ-treated DM rats following DATS administration. Taken together, our results suggested that DATS reduced AGE-induced cardiomyocyte apoptosis by eliminating ROS and downstream PKCδ signaling, suggesting that DATS has potential in diabetic cardiomyopathy (DCM) treatment.