Oxidative stress triggers neuronal caspase-independent death: Endonuclease G involvement in programmed cell death-type III

• Published in: Cellular and molecular life sciences : CMLS Vol. 66; no. 16; pp. 2773 - 2787
• Main Authors: Higgins, Gavin C, Beart, Philip M, Nagley, Phillip
• Format: Journal Article
• Language: English
• Published: Basel Basel : SP Birkhäuser Verlag Basel 01.08.2009; SP Birkhäuser Verlag Basel; Springer Nature B.V
• Subjects: Animals; Apoptosis; Apoptosis - drug effects; Apoptosis - physiology; Biochemistry; Biomedical and Life Sciences; Biomedicine; Caspase 3 - metabolism; Caspase 3 - physiology; Caspase 7 - metabolism; Caspase 7 - physiology; Caspase-3; Caspase-7; Caspases, Effector - metabolism; Caspases, Effector - physiology; Cell activation; Cell Biology; Cell death; Cellular biology; Cytochrome c; death; Deoxyribonucleic acid; DNA; DNA fragmentation; DNA Fragmentation - drug effects; Endodeoxyribonucleases - metabolism; Endodeoxyribonucleases - physiology; Endonuclease; Enzymes; Fragmentation; Hydrogen peroxide; Hydrogen Peroxide - pharmacology; Life Sciences; Membrane Potential, Mitochondrial - drug effects; Mice; Mice, Inbred Strains; mitochondria; Mitochondrial Membranes - drug effects; Molecular biology; Mortality; Necrosis; Neurons; Neurons - cytology; Neurons - drug effects; Oxidative Stress; plasma membrane; Research Article; shrinkage; siRNA; small interfering RNA; Staurosporine; Staurosporine - pharmacology; Oxidative stress; Mitochondria; Neurons; Programmed cell death; Endonuclease G; Caspases; Apoptosis; Necrosis
• ISSN: 1420-682X; 1420-9071; 1420-9071
• DOI: 10.1007/s00018-009-0079-2

To characterize neuronal death, primary cortical neurons (C57/Black 6 J mice) were exposed to hydrogen peroxide (H₂O₂) and staurosporine. Both caused cell shrinkage, nuclear condensation, DNA fragmentation and loss of plasma membrane integrity. Neither treatment induced caspase-7 activity, but caspase-3 was activated by staurosporine but not H₂O₂. Each treatment caused redistribution from mitochondria of both endonuclease G (Endo G) and cytochrome c. Neurons knocked down for Endo G expression using siRNA showed reduction in both nuclear condensation and DNA fragmentation after treatment with H₂O₂, but not staurosporine. Endo G suppression protected cells against H₂O₂-induced cell death, while staurosporine-induced death was merely delayed. We conclude that staurosporine induces apoptosis in these neurons, but severe oxidative stress leads to Endo G-dependent death, in the absence of caspase activation (programmed cell death-type III). Therefore, oxidative stress triggers in neurons a form of necrosis that is a systematic cellular response subject to molecular regulation.