title: Expression and regulation of antioxidant enzymes in the developing limb support a function of ROS in interdigital cell death.
abstract: Vertebrate limb development is a well-studied model of apoptosis; however, little is known about the intracellular molecules involved in activating the cell death machinery. We have shown that high levels of reactive oxygen species (ROS) are present in the interdigital 'necrotic' tissue of mouse autopod, and that antioxidants can reduce cell death. Here, we determined the expression pattern of several antioxidant enzymes in order to establish their role in defining the areas with high ROS levels. We found that the genes encoding the superoxide dismutases and catalase are expressed in autopod, but they are downregulated in the interdigital regions at the time ROS levels increased and cell death was first detected. The possible role of superoxide and/or peroxide in activating cell death is supported by the protective effect of a superoxide dismutase/catalase mimetic. Interestingly, we found that peroxidase activity and glutathione peroxidase-4 gene (Gpx4) expression were restricted to the non-apoptotic tissue (e.g., digits) of the developing autopod. Induction of cell death with retinoic acid caused an increase in ROS and decrease in peroxidase activity. Even more inhibition of glutathione peroxidase activity leads to cell death in the digits, suggesting that a decrease in antioxidant activity, likely due to Gpx4, caused an increase in ROS levels, thus triggering apoptosis.
authors.affiliation: Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, AP 510-3, Cuernavaca, Mor. 62250, México.
authors.forename: Denhí
authors.initials: D
authors.lastname: Schnabel
authors.forename: Enrique
authors.initials: E
authors.lastname: Salas-Vidal
authors.forename: Verónica
authors.initials: V
authors.lastname: Narváez
authors.forename: María del Rayo
authors.initials: Mdel R
authors.lastname: Sánchez-Carbente
authors.forename: David
authors.initials: D
authors.lastname: Hernández-García
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Cuervo
authors.forename: Luis
authors.initials: L
authors.lastname: Covarrubias
mesh_terms: D000818:Animals; D017209:Apoptosis; D002374:Catalase / Q000235:genetics; D005121:Extremities / Q000196:embryology*; D018507:Gene Expression Regulation, Developmental; D005979:Glutathione Peroxidase / Q000235:genetics* / Q000502:physiology; D051379:Mice; D012333:RNA, Messenger / Q000032:analysis; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000235:genetics; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D014212:Tretinoin; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase