ABSTRACT
Increased oxidative stress is widely accepted to be a factor in the development and progression of Alzheimer's disease. Triazine derivatives possess a wide range of pharmacological activities including anti-oxidative and anti-inflammatory actions. In this study, we aimed to investigate the possible protective effect of 3-thioethyl-5,6-dimethoxyphenyl-1,2,4-triazine [TEDMT] on H2O2-induced neurite outgrowth impairment and apoptosis in neuron-like PC 12 cells. We pretreated PC12 cells with 5, 7, and 10 uM of TEDMT followed by adding H2O2 as an oxidative stress agent. We found that TEDMT contributed to up-regulation of Bcl-2, down regulation of Bax protein and reduction of cleaved Caspase-3 and PARP proteins. Moreover, TEDMT could inhibit the phosphorylation of different mitogen activated protein kinases [extracellular signal-regulated kinase, c-Jun N-terminal kinase and P38 mitogen-activated protein kinase]. TEDMT induced heat shock protein 70 while decreased heat shock protein 90 level. Besides we measured six different parameters of neurite outgrowth and complexity. We showed that H2O2 increased cell body area, average neurite width and the proportion of bipolar cells, while decreased average neurite length, the numbers of primary neurites and the ratio of the total neurite branching nodes to the total number of primary neurites. Interestingly, we found that TEDMT not only protects PC12 cell against H2O2-induced apoptosis, but also defends against the destructive effect of oxidative stress on the criteria of neural differentiation. Protective effect of this compound could represent a promising approach for treatment of neurodegenerative diseases
ABSTRACT
The inflammatory response requires a coordinated integration of various signaling pathway including cyclooxygenase [COX]. COX catalyzes the formation of prostaglandins from arachidonic acid. Among prostaglandins, 15-Deoxy-D12, 14-prostaglandin J2 [15d-PGJ2], an endogenous ligand of Peroxisome proliferator-activated receptor-gamma [PPAR-gamma], has been demonstrated to have anti-inflammatory actions. In this study, we investigated whether 15d-PGJ2 as a PPAR-gamma ligand could exert neuroprotective effects in rat pheochromocytoma [PC12] cells in PPAR-gamma dependent manner. In our experiment, using PC12 cells, the levels of NF-?B, Nrf2, gamma-glutamylcysteine synthetase [gamma-GCS], hemeoxygenase [HO-1] and apoptosis factors were determined using Western blot in different groups. Also cell viability was determined by the conventional MTT [3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide] reduction assay and two staining involved Hoechst staining and Acridine Ordange/Ethidiume Bromide staining respectively. Our results show that NS-398, a selective COX-2 inhibitor and 15d-PGJ2, a natural potent ligand of PPAR-gamma, were neuroprotective through modulation of at least three different, but related pathways and molecules, including NF-?B and Nrf2 signaling pathway. Our data showed that 15d-PGJ2 and NS-398 induced Nrf2 signaling pathway and its downstream factors such as HO-1 and gamma-GCS, while 15d-PGJ2 and NS-398 decreased NF-?B level. Interestingly, the observed protective effects were mediated through PPAR-gamma-dependent mechanisms, as they reversed by GW9662, an irreversible antagonist of PPAR-gamma receptor. Thus we conclude that 15d-PGJ2 as well as NS-398 exert anti cell death effect in a PPAR-gamma dependent mechanisms