Regulation of the Nrf2 Pathway by Glycogen Synthase Kinase-3β in MPP⁺-Induced Cell Damage

Recently, nuclear translocation and stability of nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2) have gained increasing attention in the prevention of oxidative stress. The present study was aimed to evaluate the regulatory role of glycogen synthase kinase-3β (GSK-3β) inhibition by tideglusib through the Nrf2 pathway in a cellular damage model. Gene silencing (siRNA-mediated) was performed to examine the responses of Nrf2-target genes (i.e., heme oxygenase-1, NAD(P)H:quinone oxidoreductase1) to siRNA depletion of Nrf2 in MPP+-induced dopaminergic cell death. Nrf2 and its downstream regulated genes/proteins were analyzed using Real-time PCR and Western Blotting techniques, respectively. Moreover, free radical production, the changes in mitochondrial membrane potential, total glutathione, and glutathione-S-transferase were examined. The possible contribution of peroxisome proliferator-activated receptor gamma (PPARγ) to tideglusib-mediated neuroprotection was evaluated. The number of viable cells and mitochondrial membrane potential were increased following GSK-3β enzyme inhibition against MPP+. HO-1, NQO1 mRNA/protein expressions and Nrf2 nuclear translocation significantly triggered by tideglusib. Moreover, the neuroprotection by tideglusib was not observed in the presence of siRNA Nrf2. Our study supports the idea that GSK-3β enzyme inhibition may modulate the Nrf2/ARE pathway in cellular damage and the inhibitory role of tideglusib on GSK-3β along with PPARγ activation may be responsible for neuroprotection

Efficient synthesis and first regioselective C-6 direct arylation of imidazo[2,1-c][1,2,4]triazine scaffold and their evaluation in H2O2-induced oxidative stress

Oxidative stress and apoptosis are both associated with various acute and chronic disorders. Thus, the aim of the present study is to synthesize imidazo[2,1-c][1,2,4]triazines derivatives and to evaluate their effects in H2O2-induced oxidative stress in human neuroblastoma cell line (SH-SY5Y cells). The effects of the compounds on cell viability were measured by MTT assay and the changes in stress and apoptosis-related proteins were investigated by PathScan® Stress and Apoptosis Signaling Antibody Array kit and Western Blot technique. In particular, four compounds were found to protect SH-SY5Y cells from H2O2-induced toxicity by increasing Bcl-2/Bax ratio, regulating PI3-K/Akt cascade and inhibiting the ERK pathway