Cytosolic and mitochondrial ROS in staurosporine-induced retinal cell apoptosis

• Author(s): Gil, Joana ; Almeida, Sandra ; Oliveira, Catarina R. ; Rego, A. Cristina
• Date: 2003
• Persistent ID: http://hdl.handle.net/10316/4797
• Origin: Estudo Geral - Universidade de Coimbra
• Subject(s): Apoptosis; Antioxidants; Calcium; Caspase-3; Mitochondria; Reactive oxygen species; Retinal cells; Staurosporine; Free radicals
• Document Type: Article
• Language: English

Description

In this study, we investigated the involvement of reactive oxygen species (ROS) and calcium in staurosporine (STS)-induced apoptosis in cultured retinal neurons, under conditions of maintained membrane integrity. The antioxidants idebenone (IDB), glutathione-ethylester (GSH/EE), trolox, and Mn(III)tetrakis (4-benzoic acid) porphyrin chloride (MnTBAP) significantly reduced STS-induced caspase-3-like activity and intracellular ROS generation. Endogenous sources of ROS production were investigated by testing the effect of the following inhibitors: 7-nitroindazole (7-NI), a specific inhibitor of the neuronal isoform of nitric oxide synthase (nNOS); arachidonyl trifluoromethyl ketone (AACOCF3), a phospholipase A2 (PLA2) inhibitor; allopurinol, a xanthine oxidase inhibitor; and the mitochondrial inhibitors rotenone and oligomycin. All these compounds decreased caspase-3-like activity and ROS generation, showing that both mitochondrial and cytosolic sources of ROS are implicated in this mechanism. STS induced a significant increase in intracellular calcium concentration ([Ca2+]i), which was partially prevented in the presence of IDB and GSH/EE, indicating its dependence on ROS generation. These two antioxidants and the inhibitors allopurinol and 7-NI also reduced the number of TdT-mediated dUTP nick-end labeling-positive cells. Thus, endogenous ROS generation and the rise in intracellular calcium are important inter-players in STS-triggered apoptosis. Furthermore, the antioxidants may help to prolong retinal cell survival upon apoptotic cell death. http://www.sciencedirect.com/science/article/B6T38-4B1Y892-D/1/de8345fb5df912dddbc572b28cc1f4be