title: Cell death activation during cavitation of embryoid bodies is mediated by hydrogen peroxide.
abstract: The formation of the proamniotic cavity is the first indication of programmed cell death associated to a morphogenetic process in mammals. Although some growth factors have been implicated in proamniotic cavitation, very little is known about the intracellular mechanisms that control the cell death process itself. Reactive oxygen species (ROS) are potent activators of cell death, thus, in the present work we evaluated the role of ROS during the cavitation of embryoid bodies (EBs), a common model to study proamniotic cavitation. During cavitation, ROS concentration increases in the inner cells of EBs, and this ROS accumulation appears to be associated with the mitochondrial respiratory activity. In agreement with a role of ROS in cavitation, EBs derived from ES cells that overproduce catalase, an enzyme that specifically degrades hydrogen peroxide, do not cavitate, and caspase activation and cell death is markedly decreased. Notably, cell death, but not the rise in ROS, during EB cavitation is caspase-dependent. The apoptosis-inducing factor (Aif) is released from the mitochondria during cavitation, but EBs derived from Aif(-/y) ES cells cavitate and ROS levels in the inner cells remain high. We conclude that hydrogen peroxide is a cell death activating signal essential for EB cavitation, suggesting that cell death during proamniotic cavitation is mediated by ROS.
authors.affiliation: Department of Developmental Genetics and Molecular Physiology, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, México.
authors.forename: David
authors.initials: D
authors.lastname: Hernández-García
authors.forename: Susana
authors.initials: S
authors.lastname: Castro-Obregón
authors.forename: Sandra
authors.initials: S
authors.lastname: Gómez-López
authors.forename: Concepción
authors.initials: C
authors.lastname: Valencia
authors.forename: Luis
authors.initials: L
authors.lastname: Covarrubias
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D051033:Apoptosis Inducing Factor / Q000378:metabolism; D020169:Caspases / Q000378:metabolism; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects* / Q000502:physiology; D002460:Cell Line; D002470:Cell Survival; D004622:Embryo, Mammalian / Q000166:cytology / Q000502:physiology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D051379:Mice; D009942:Organometallic Compounds / Q000378:metabolism; D016877:Oxidants / Q000494:pharmacology*; D018384:Oxidative Stress; D010269:Paraquat / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012459:Salicylates / Q000378:metabolism; D014465:Ultrasonics; D024483:Vitamin K 3 / Q000378:metabolism
chemical_list: D000975:Antioxidants; D051033:Apoptosis Inducing Factor; C433928:EUK-134; D009942:Organometallic Compounds; D016877:Oxidants; D017382:Reactive Oxygen Species; D012459:Salicylates; D024483:Vitamin K 3; D006861:Hydrogen Peroxide; D002374:Catalase; D020169:Caspases; D010269:Paraquat