title: Characterization of eicosanoid synthesis in a genetic ablation model of ceramide kinase.
abstract: Multiple reports have demonstrated a role for ceramide kinase (CERK) in the production of eicosanoids. To examine the effects of the genetic ablation of CERK on eicosanoid synthesis, primary mouse embryonic fibroblasts (MEFs) and macrophages were isolated from CERK(-/-) and CERK(+/+) mice, and the ceramide-1-phosphate (C1P) and eicosanoid profiles were investigated. Significant decreases were observed in multiple C1P subspecies in CERK-/- cells as compared to CERK(+/+) cells with overall 24% and 48% decreases in total C1P. In baseline experiments, the levels of multiple eicosanoids were significantly lower in the CERK(-/-) cells compared with wild-type cells. Importantly, induction of eicosanoid synthesis by calcium ionophore was significantly reduced in the CERK(-/-) MEFs. Our studies also demonstrate that the CERK(-/-) mouse has adapted to loss of CERK in regards to airway hyper-responsiveness as compared with CERK siRNA treatment. Overall, we demonstrate that there are significant differences in eicosanoid levels in ex vivo CERK(-/-) cells compared with wild-type counterparts, but the effect of the genetic ablation of CERK on eicosanoid synthesis and the serum levels of C1P was not apparent in vivo.
authors.affiliation: Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Mietla
authors.forename: Dayanjan S
authors.initials: DS
authors.lastname: Wijesinghe
authors.forename: L Alexis
authors.initials: LA
authors.lastname: Hoeferlin
authors.forename: Michael D
authors.initials: MD
authors.lastname: Shultz
authors.forename: Ramesh
authors.initials: R
authors.lastname: Natarajan
authors.forename: Alpha A
authors.initials: AA
authors.lastname: Fowler
authors.forename: Charles E
authors.initials: CE
authors.lastname: Chalfant
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002518:Ceramides / Q000097:blood; D004195:Disease Models, Animal; D015777:Eicosanoids / Q000096:biosynthesis*; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D011247:Pregnancy; D011270:Pregnancy, Animal
chemical_list: D002518:Ceramides; D015777:Eicosanoids; C065576:ceramide 1-phosphate; D017853:Phosphotransferases (Alcohol Group Acceptor); C066324:ceramide kinase
keywords: ceramide-1-phosphate; cytosolic phospholipase A2; eicosanoids; inflammation