pOxidative 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 Hsub2/subOsub2/sub, 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 iin situ/i 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 iin vivo/i./p
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机译：以前，氧化应激与神经酰胺代谢的调节有关。在本研究中，研究了其对二氢神经酰胺去饱和酶的作用。为了刺激氧化应激，用H 2 O 2 ，甲萘醌或叔丁基氢过氧化物处理HEK（人胚肾）-293，MCF7，A549和SMS-KCNR细胞。在所有细胞系中，通过LC（液相色谱）/ MS测量，在氧化应激下观察到二氢神经酰胺的增加。相反，总神经酰胺水平相对不变。从机理上讲，二氢神经酰胺去饱和酶活性是通过原位测定法测定的，并以时间和剂量依赖性的方式降低。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降解。总之，氧化应激可有效抑制二氢神经酰胺去饱和酶，从而导致体内二氢神经酰胺水平显着升高。
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