Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, 29425, USA.
Biochem J. 2010 Mar 29;427(2):265-74. doi: 10.1042/BJ20091589.
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.
先前的研究表明，氧化应激参与了神经酰胺代谢的调控。在本研究中，我们研究了其对二氢神经酰胺去饱和酶的影响。为了刺激氧化应激，用 H2O2、甲萘醌或叔丁基过氧化物处理 HEK（人胚肾）-293、MCF7、A549 和 SMS-KCNR 细胞。在所有细胞系中，如通过 LC（液相色谱）/MS 所测，氧化应激会导致二氢神经酰胺增加。相比之下，总神经酰胺水平相对不变。从机制上讲，通过原位测定法测定二氢神经酰胺去饱和酶的活性，并呈时间和剂量依赖性下降。有趣的是，未观察到蛋白质水平的可检测变化，表明氧化应激不会诱导二氢神经酰胺去饱和酶的降解。总之，氧化应激会导致二氢神经酰胺去饱和酶的强烈抑制，从而导致体内二氢神经酰胺水平显著升高。
