Ting Hsiu-Chi, Chao Yu-Jen, Hsu Yuan-Hao Howard
Department of Chemistry, Tunghai University, Taichung 40704, Taiwan.
Department of Chemistry, Tunghai University, Taichung 40704, Taiwan; Life Science Research Center, Tunghai University, Taichung 40704, Taiwan.
J Nutr Biochem. 2015 Jul;26(7):769-75. doi: 10.1016/j.jnutbio.2015.02.005. Epub 2015 Mar 26.
Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), known as ω-3 polyunsaturated fatty acid (PUFA), are common nutrients in daily food intake and have been shown to prevent cardiovascular disease and improve cardiac functions. Cardiolipin is a mitochondrial phospholipid necessary for maintaining physiological function of mitochondria. Several studies have indicated that the cardiolipin acyl chain compositions affect the function of cardiolipin and mitochondria. Here, we investigated the structural changes of cardiolipin after DHA and EPA supplementation and compared them to arachidonic acid (AA) treatment. H9c2 cardiac myoblast was used as a cell model, and cardiolipin species was monitored and identified via LC-MS and MS/MS. Our results showed distinct mass envelopes of cardiolipin with the same carbon number but different double bonds in mass spectrum. There were 116 cardiolipin species with 36 distinct mass in 6 mass envelopes identified by MS/MS. Three days of PUFA treatment resulted in decreases of low-molecular-weight cardiolipin and increases of high-molecular-weight cardiolipin, suggesting the incorporation of exogenous DHA, EPA and AA into mitochondrial cardiolipin. PUFA incorporation was further verified by MS/MS analysis. More importantly, we found that DHA supplementation elevated the percent content of less unsaturated cardiolipin species and highly unsaturated cardiolipin species, containing ω-3 fatty acyl chains, indicating a ω-3 fatty acid incorporation mechanism with peroxidation protection. Our results indicate that PUFA supplementation differentially perturbed the fatty acyl chain compositions in the mitochondrial cardiolipin in the H9c2 cardiac myoblast, suggesting that mitochondrial membrane and the function of mitochondria are susceptible to exogenous lipid species.
二十二碳六烯酸（DHA）和二十碳五烯酸（EPA），即ω-3多不饱和脂肪酸（PUFA），是日常食物摄入中的常见营养素，已被证明可预防心血管疾病并改善心脏功能。心磷脂是维持线粒体生理功能所必需的线粒体磷脂。多项研究表明，心磷脂的酰基链组成会影响心磷脂和线粒体的功能。在此，我们研究了补充DHA和EPA后心磷脂的结构变化，并将其与花生四烯酸（AA）处理进行比较。使用H9c2心肌成纤维细胞作为细胞模型，通过液相色谱-质谱联用（LC-MS）和串联质谱（MS/MS）监测并鉴定心磷脂种类。我们的结果显示，质谱图中心磷脂具有相同碳原子数但双键不同的明显质量包络。通过MS/MS在6个质量包络中鉴定出116种心磷脂，具有36种不同质量。PUFA处理三天导致低分子量心磷脂减少，高分子量心磷脂增加，表明外源性DHA、EPA和AA掺入了线粒体心磷脂。通过MS/MS分析进一步验证了PUFA的掺入。更重要的是，我们发现补充DHA提高了含有ω-3脂肪酰链的不饱和程度较低的心磷脂种类和高度不饱和的心磷脂种类的百分比含量，表明存在具有过氧化保护作用的ω-3脂肪酸掺入机制。我们的结果表明，补充PUFA会差异性地扰乱H9c2心肌成纤维细胞线粒体心磷脂中的脂肪酰链组成，提示线粒体膜和线粒体功能对外源性脂质种类敏感。
