title: Neuronal necrosis and spreading death in a Drosophila genetic model.
abstract: Brain ischemia often results in neuronal necrosis, which may spread death to neighboring cells. However, the molecular events of neuronal necrosis and the mechanisms of this spreading death are poorly understood due to the limited genetic tools available for deciphering complicated responses in mammalian brains. Here, we engineered a Drosophila model of necrosis in a sub-population of neurons by expressing a leaky cation channel in the Drosophila eye. Expression of this channel caused necrosis in defined neurons as well as extensive spreading of cell death. Jun N-terminal kinase (JNK)-mediated, caspase-independent apoptosis was the primary mechanism of cell death in neurons, while caspase-dependent apoptosis was primarily involved in non-neuronal cell death. Furthermore, the JNK activation in surrounding neurons was triggered by reactive oxygen species (ROS) and Eiger (Drosophila tumor necrosis factor α (TNFα)) released from necrotic neurons. Because the Eiger/ROS/JNK signaling was also required for cell death induced by hypoxia and oxidative stress, our fly model of spreading death may be similar to brain ischemia in mammals. We performed large-scale genetic screens to search for novel genes functioning in necrosis and/or spreading death, from which we identified several classes of genes. Among them, Rho-associated kinase (ROCK) had been reported as a promising drug target for stroke treatment with undefined mechanisms. Our data indicate that ROCK and the related trafficking pathway genes regulate neuronal necrosis. We propose the suppression of the function of the trafficking system, ROS and cytokines, such as TNFα, as translational applications targeting necrosis and spreading death.
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Peking University, Beijing, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Yang
authors.forename: L
authors.initials: L
authors.lastname: Hou
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: J
authors.initials: J
authors.lastname: Ni
authors.forename: L
authors.initials: L
authors.lastname: Liu
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D017209:Apoptosis; D002545:Brain Ischemia / Q000378:metabolism; D061945:Caspase Inhibitors / Q000494:pharmacology; D020169:Caspases / Q000378:metabolism; D054910:Compound Eye, Arthropod / Q000294:innervation / Q000378:metabolism / Q000473:pathology; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D020935:MAP Kinase Signaling System; D008565:Membrane Proteins / Q000378:metabolism; D009336:Necrosis; D009474:Neurons / Q000502:physiology*; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism; D018091:Receptors, AMPA / Q000096:biosynthesis / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics
chemical_list: D061945:Caspase Inhibitors; D020169:Caspases; D029721:Drosophila Proteins; D048031:JNK Mitogen-Activated Protein Kinases; D008565:Membrane Proteins; D017382:Reactive Oxygen Species; D018091:Receptors, AMPA; D011994:Recombinant Proteins; C464573:egr protein, Drosophila