PDF(Pubmed)
Abstract：
Ceramides (CERs) are key intermediate sphingolipids implicated in contributing to mitochondrial dysfunction and the development of multiple metabolic conditions. Despite the growing evidence of CER role in disease risk, kinetic methods to measure CER turnover are lacking, particularly using in vivo models. The utility of orally administered 13C3, 15N l-serine, dissolved in drinking water, was tested to quantify CER 18:1/16:0 synthesis in 10-week-old male and female C57Bl/6 mice. To generate isotopic labeling curves, animals consumed either a control diet or high-fat diet (HFD; n = 24/diet) for 2 weeks and varied in the duration of the consumption of serine-labeled water (0, 1, 2, 4, 7, or 12 days; n = 4 animals/day/diet). Unlabeled and labeled hepatic and mitochondrial CERs were quantified using liquid chromatography tandem MS. Total hepatic CER content did not differ between the two diet groups, whereas total mitochondrial CERs increased with HFD feeding (60%, P < 0.001). Within hepatic and mitochondrial pools, HFD induced greater saturated CER concentrations (P < 0.05) and significantly elevated absolute turnover of 16:0 mitochondrial CER (mitochondria: 59%, P < 0.001 vs. liver: 15%, P = 0.256). The data suggest cellular redistribution of CERs because of the HFD. These data demonstrate that a 2-week HFD alters the turnover and content of mitochondrial CERs. Given the growing data on CERs contributing to hepatic mitochondrial dysfunction and the progression of multiple metabolic diseases, this method may now be used to investigate how CER turnover is altered in these conditions.
摘要：
神经酰胺（CERs）是关键的中间鞘脂，与线粒体功能障碍和多种代谢条件的发展有关。尽管越来越多的证据表明CER在疾病风险中的作用，缺乏测量CER周转率的动力学方法，特别是使用体内模型。口服13C3，15N1-丝氨酸的效用，溶解在饮用水中，在10周龄的雄性和雌性C57Bl/6小鼠中对CER18:1/16:0合成进行定量测试。要生成同位素标记曲线，动物消耗对照饮食或高脂肪饮食(HFD;n=24/饮食)2周,并且丝氨酸标记水的消耗持续时间不同(0、1、2、4、7或12天;n=4只动物/天/饮食)。使用液相色谱串联MS定量未标记和标记的肝脏和线粒体CER。两个饮食组之间的总肝脏CER含量没有差异，而线粒体总CER随着HFD喂养而增加(60%，P<0.001)。在肝脏和线粒体池内，HFD诱导更大的饱和CER浓度（P<0.05）和显着提高16：0线粒体CER的绝对周转（线粒体：59％，P<0.001vs.肝脏：15%，P=0.256）。数据表明，由于HFD，CER的细胞重新分布。这些数据表明，2周的HFD会改变线粒体CER的周转和含量。鉴于越来越多的数据中的CER有助于肝线粒体功能障碍和多代谢疾病的进展，这种方法现在可用于研究在这些情况下CER周转是如何改变的.
