title: Dihydroceramide desaturase activity is modulated by oxidative stress.
abstract: Oxidative stress has been implicated previously in the regulation of ceramide metabolism. In the present study, its effects on dihydroceramide desaturase were investigated. To stimulate oxidative stress, HEK (human embyronic kidney)-293, MCF7, A549 and SMS-KCNR cells were treated with H2O2, menadione or tert-butylhydroperoxide. In all cell lines, an increase in dihydroceramide was observed upon oxidative stress as measured by LC (liquid chromatography)/MS. In contrast, total ceramide levels were relatively unchanged. Mechanistically, dihydroceramide desaturase activity was measured by an in situ assay and decreased in a time- and dose-dependent fashion. Interestingly, no detectable changes in the protein levels were observed, suggesting that oxidative stress does not induce degradation of dihydroceramide desaturase. In summary, oxidative stress leads to potent inhibition of dihydroceramide desaturase resulting in significant elevation in dihydroceramide levels in vivo.
authors.affiliation: Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, 29425, USA.
authors.forename: Jolanta
authors.initials: J
authors.lastname: Idkowiak-Baldys
authors.forename: Aintzane
authors.initials: A
authors.lastname: Apraiz
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Rahmaniyan
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Clarke
authors.forename: Jacqueline M
authors.initials: JM
authors.lastname: Kraveka
authors.forename: Aintzane
authors.initials: A
authors.lastname: Asumendi
authors.forename: Yusuf A
authors.initials: YA
authors.lastname: Hannun
mesh_terms: D002460:Cell Line; D002518:Ceramides / Q000032:analysis; D006801:Humans; D018384:Oxidative Stress / Q000187:drug effects; D010088:Oxidoreductases / Q000032:analysis / Q000378:metabolism*; D055550:Protein Stability
chemical_list: D002518:Ceramides; C109343:dihydroceramide; D010088:Oxidoreductases; C108138:dihydroceramide desaturase