Platelets are sensitive cells and are easily activated by different stimulants in the circulation system. It is known that tumor necrosis factor-alpha (TNF-α) is a proinflammatory cytokine and plays a role in inflammation. The role of TNF-α in the apoptotic process in blood platelets is unknown. | Turkish Journal of Biology Turk J Biol (2017) 41: 31-40 © TÜBİTAK doi: Research Article Tumor necrosis factor-alpha induced caspase-3 activation-related iNOS gene expression in ADP-activated platelets 1,2, 3 4 2 Özge ÇEVİK *, Zelal ADIGÜZEL , Ahmet Tarık BAYKAL , Azize ŞENER Department of Biochemistry, Faculty of Pharmacy, Cumhuriyet University, Sivas, Turkey 2 Department of Biochemistry, Faculty of Pharmacy, Marmara University, İstanbul, Turkey 3 TÜBİTAK Marmara Research Center, Genetic Engineering and Biotechnology Institute (GEBİ), Kocaeli, Turkey 4 Department of Biochemistry, School of Medicine, Acibadem University, İstanbul, Turkey 1 Received: Accepted/Published Online: Final Version: Abstract: Platelets are sensitive cells and are easily activated by different stimulants in the circulation system. It is known that tumor necrosis factor-alpha (TNF-α) is a proinflammatory cytokine and plays a role in inflammation. The role of TNF-α in the apoptotic process in blood platelets is unknown. In order to study the formation of apoptosis in platelets after incubation with TNF-α and/or ADP, several biomarkers were chosen: phosphatidylserine (PS) exposure and P-selectin binding; cGMP, Cyt-c, and Ca2+ levels and NOS activation; and gene and protein expression of caspase-3 and iNOS. Platelets were incubated with 100 pg/mL TNF-α and/or 50 mM iNOS specific inhibitor, such as at 1400 W for 1 h at 37 °C in the presence of 5 µM ADP. According to the results, the levels of PS exposure and P-selectin binding were significantly higher in TNF-α + ADP platelets, which decreased with the addition of 1400 W. A significant induction in cGMP, Cyt-c, and Ca2+ levels was observed in platelets treated with TNF-α + ADP. On the other hand, the upregulation of the apoptotic gene caspase-3 and iNOS expression levels in TNF-α-treated and ADP-activated platelets was significantly reversed .
