RESUMEN
Brain-derived neurotrophic factor (BDNF) plays an important role in neuronal cell apoptosis. The antisense RNA of brain-derived neurotrophic factor (BDNF-AS) is a natural antisense transcript that is transcribed opposite the gene that encodes BDNF. The aim of this study was to determine whether knockdown of BDNF-AS can suppress hypoxia/reoxygenation (H/R)-induced neuronal cell apoptosis and whether this is mediated by the BDNF-TrkB-PI3K/Akt pathway. We detected the expression of BDNF and BDNF-AS in brain tissue from 20 patients with cerebral infarction and five patients with other diseases (but no cerebral ischemia). We found that BDNF expression was significantly downregulated in patients with cerebral infarction, whereas the expression of BDNF-AS was significantly upregulated. In both human cortical neurons (HCN2) and human astrocytes, H/R significantly induced the expression of BDNF-AS, but significantly decreased BDNF expression. H/R also significantly induced apoptosis and reduced the mitochondrial membrane potential in these cells. Following downregulation of BDNF-AS by siRNA in human cortical neurons and human astrocyte cells, BDNF expression was significantly upregulated and the H/R-induced upregulation of BDNF-AS was significantly attenuated. BDNF-AS siRNA inhibited H/R-induced cell apoptosis and ameliorated the H/R-induced suppression of mitochondrial membrane potential. H/R inhibited the expression of BDNF, p-AKT/AKT, and TrKB, and this inhibition was recovered by BDNF-AS siRNA. In summary, this study indicates that BDNF-AS siRNA induces activation of the BDNF-TrkB-PI3K/Akt pathway following H/R-induced neurotoxicity. These findings will be useful toward the application of BDNF-AS siRNA for the treatment of neurodegenerative diseases.
Asunto(s)
Apoptosis/fisiología , Isquemia Encefálica/metabolismo , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Encéfalo/metabolismo , ARN Largo no Codificante/metabolismo , Daño por Reperfusión/metabolismo , Astrocitos/metabolismo , Astrocitos/patología , Encéfalo/patología , Isquemia Encefálica/patología , Isquemia Encefálica/terapia , Factor Neurotrófico Derivado del Encéfalo/antagonistas & inhibidores , Factor Neurotrófico Derivado del Encéfalo/genética , Células Cultivadas , Técnicas de Silenciamiento del Gen , Humanos , Glicoproteínas de Membrana/metabolismo , Potencial de la Membrana Mitocondrial/fisiología , Neuronas/metabolismo , Neuronas/patología , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , ARN Largo no Codificante/antagonistas & inhibidores , ARN Largo no Codificante/genética , ARN Interferente Pequeño , Receptor trkB/metabolismo , Daño por Reperfusión/patología , Daño por Reperfusión/terapia , Transducción de SeñalRESUMEN
Parkinson's disease (PD) is a common degenerative disease that lacks efficient treatment. Myelin-associated neurite outgrowth inhibitor A (Nogo-A) is relevant with inhibition of nerve regeneration and may play vital role in pathogenesis of PD. The study aimed to establish the shRNA expression plasmids of Nogo-A gene and explore the regulatory effects of Nogo-A silencing on the expression of inflammation factor tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) as well as tyrosine hydroxylase (TH) in lipopolysaccharide- (LPS-) stimulated rat PC12 cells. The results showed that both mRNA and protein levels of Nogo-A in pGenesil-nogoA-shRNA group were downregulated. The viabilities of PC12 cells decreased with increase of LPS concentrations. LPS significantly increased the supernatant TNF-alpha and IL-6 concentrations and reduced TH protein expression in PC12 cells, while silencing Nogo-A could block these effects. These results suggested that LPS can activate PC12 cells to secrete inflammatory cytokines and lower the TH expression, which can be regulated by Nogo-A gene silencing. Nogo-A silencing might provide new ideas for PD treatment in the future.