Institute for Food Toxicology, University of Veterinary Medicine Hannover, Hannover, Germany; Chair of Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Wuppertal, Germany.
Rudolf Buchheim Institute of Pharmacology, Justus Liebig University Giessen, Giessen, Germany.
Prostaglandins Other Lipid Mediat. 2019 Oct;144:106334. doi: 10.1016/j.prostaglandins.2019.04.004. Epub 2019 Apr 19.
In mammals, epoxy-polyunsaturated fatty acids (epoxy-PUFA) are enzymatically formed from naturally occurring all-cis PUFA by cytochrome P450 monooxygenases leading to the generation of cis-epoxy-PUFA (mixture of R,S- and S,R-enantiomers). In addition, also non-enzymatic chemical peroxidation gives rise to epoxy-PUFA leading to both, cis- and trans-epoxy-PUFA (mixture of R,R- and S,S-enantiomers). Here, we investigated for the first time trans-epoxy-PUFA and the trans/cis-epoxy-PUFA ratio as potential new biomarker of lipid peroxidation. Their formation was analyzed in correlation with the formation of isoprostanes (IsoP), which are commonly used as biomarkers of oxidative stress. Five oxidative stress models were investigated including incubations of three human cell lines as well as the in vivo model Caenorhabditis elegans with tert-butyl hydroperoxide (t-BOOH) and analysis of murine kidney tissue after renal ischemia reperfusion injury (IRI). A comprehensive set of IsoP and epoxy-PUFA derived from biologically relevant PUFA (ARA, EPA and DHA) was simultaneously quantified by LC-ESI(-)-MS/MS. Following renal IRI only a moderate increase in the kidney levels of IsoP and no relevant change in the trans/cis-epoxy-PUFA ratio was observed. In all investigated cell lines (HCT-116, HepG2 and Caki-2) as well as C. elegans a dose dependent increase of both, IsoP and the trans/cis-epoxy-PUFA ratio in response to the applied t-BOOH was observed. The different cell lines showed a distinct time dependent pattern consistent for both classes of autoxidatively formed oxylipins. Clear and highly significant correlations of the trans/cis-epoxy-PUFA ratios with the IsoP levels were found in all investigated cell lines and C. elegans. Based on this, we suggest the trans/cis-epoxy-PUFA ratio as potential new biomarker of oxidative stress, which warrants further investigation.
在哺乳动物中，环氧化多不饱和脂肪酸（epoxy-PUFA）是由细胞色素 P450 单加氧酶从天然存在的全顺式 PUFA 酶促形成的，导致顺式环氧-PUFA（R,S-和 S,R-对映异构体的混合物）的生成。此外，非酶促化学过氧化也会导致环氧-PUFA 的产生，从而导致顺式和反式环氧-PUFA（R,R-和 S,S-对映异构体的混合物）的产生。在这里，我们首次研究了反式环氧-PUFA 及其反式/顺式环氧-PUFA 比值作为脂质过氧化的潜在新生物标志物。分析了它们的形成与异前列腺素（IsoP）的形成的相关性，IsoP 通常被用作氧化应激的生物标志物。研究了 5 种氧化应激模型，包括三种人细胞系的孵育以及使用叔丁基过氧化氢（t-BOOH）的秀丽隐杆线虫体内模型和肾缺血再灌注损伤（IRI）后的鼠肾组织分析。通过 LC-ESI(-)-MS/MS 同时定量分析了来自生物相关 PUFA（ARA、EPA 和 DHA）的一套全面的 IsoP 和环氧-PUFA。肾 IRI 后，仅观察到肾脏中 IsoP 水平适度增加，反式/顺式环氧-PUFA 比值无明显变化。在所研究的所有细胞系（HCT-116、HepG2 和 Caki-2）以及秀丽隐杆线虫中，均观察到 t-BOOH 剂量依赖性地增加 IsoP 和反式/顺式环氧-PUFA 比值。不同的细胞系表现出与这两类自动氧化形成的 oxylipin 一致的明显的时间依赖性模式。在所有研究的细胞系和秀丽隐杆线虫中，均发现反式/顺式环氧-PUFA 比值与 IsoP 水平之间存在明显且高度显著的相关性。基于此，我们建议反式/顺式环氧-PUFA 比值作为氧化应激的潜在新生物标志物，值得进一步研究。
