title: Hypoxic preconditioning requires the apoptosis protein CED-4 in C. elegans.
abstract: Hypoxic preconditioning (HP) is a rapid and reversible proadaptive response to mild hypoxic exposure with such a response protecting cells from subsequent hypoxic or ischemic insult. HP mechanisms are of great interest because of their therapeutic potential and insight into metabolic adaptation and cell death. HP has been widely demonstrated in the vertebrate subphylum but not in invertebrates. Here, we report that the nematode Caenorhabditis elegans has a potent HP mechanism that protects the organism as well as its neurons and myocytes from hypoxic injury. The time course of C. elegans HP was consistent with vertebrate-delayed HP, appearing 16 hr after preconditioning and lasting at least 36 hr. The apoptosis pathway has been proposed as either a trigger or target of HP. Testing of mutations in the canonical C. elegans apoptosis pathway showed that in general, genes in this pathway are not required for HP. However, loss-of-function mutations in ced-4, which encodes an Apaf-1 homolog, completely blocked HP. RNAi silencing of ced-4 in adult animals immediately preceding preconditioning blocked HP, indicating that CED-4 is required in adults during or after preconditioning. CED-4/Apaf-1 is essential for HP in C. elegans and acts through a mechanism independent of the classical apoptosis pathway.
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
authors.forename: Nupur
authors.initials: N
authors.lastname: Dasgupta
authors.forename: Aditya M
authors.initials: AM
authors.lastname: Patel
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Scott
authors.forename: C Michael
authors.initials: CM
authors.lastname: Crowder
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D017173:Caenorhabditis elegans / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000502:physiology*; D002135:Calcium-Binding Proteins / Q000502:physiology*; D000860:Hypoxia / Q000378:metabolism*; D019194:Ischemic Preconditioning / Q000379:methods; D010100:Oxygen / Q000502:physiology*
chemical_list: D029742:Caenorhabditis elegans Proteins; D002135:Calcium-Binding Proteins; C089224:Ced-4 protein, C elegans; D010100:Oxygen