Elongases FEN1/ELO2 and SUR4/ELO3 are important enzymes involved in the elongation of long-chain fatty acids (LCFAs) to very long-chain fatty acids (VLCFAs) in Saccharomyces cerevisiae. The molecular mechanism of the involvement of these elongases in lipotoxicity is unclear. In the present study, we investigated the role of VLCFA elongases in oleic acid-mediated yeast cytotoxicity. The spot test showed that yeast strains with the deletion of ELO2 or ELO3 were strikingly sensitive to oleic acid, while there was no change on the growth of strain with deleted ELO1 which was involved in the elongation of C₁₄ fatty acid (FA) to C₁₆ FA. By using GC–MS, the unsaturation index was increased in elo2△ and elo3△ mutants after treatment with oleic acid (OLA). However, the proportion of VLCFAs was increased in response to OLA in the wild-type strain. The growth inhibition of elo2△ and elo3△ could be partially rescued by two commonly used antioxidant agents N-acetyl cysteine (NAC) and Ascorbic acid (VC). The further study showed that exposure to excess OLA led to an increase in the levels of reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS), and a decline in the quantity of reduced glutathione (GSH) in both the wild type and mutant strains. However, the antioxidant enzyme activities of superoxide dismutase (SOD) and catalase (CAT) were increased in the wild type and elo1△ strains, while they were significantly decreased in the mutants of elo2△ and elo3△ after treated with excess OLA. Thus, oxidative damage mainly contributed to the cell death induced by OLA in ole2△ and ole3△. Taken together, although disruption of ELO2 or ELO3 did not affect the cellular lipid unsaturation, they altered the distribution and propotion of cellular VLCFAs, leading to the cell membrane impairment, which augmented the ability of OLA to permeabilize the plasma membrane. The data suggest that the very long-chain fatty acids elongases ELO2 and ELO3 play important roles in lipotoxic cell death induced by OLA through maintaining a balanced FA composition in plasma membrane.

延长酶FEN1 / ELO2和SUR4 / ELO3是重要的酶，涉及酿酒酵母中长链脂肪酸（LCFA）延伸为超长链脂肪酸（VLCFA）的过程。这些延长酶参与脂毒性的分子机制尚不清楚。在本研究中，我们调查了VLCFA延长酶在油酸介导的酵母细胞毒性中的作用。现场测试表明，缺失ELO2或ELO3的酵母菌株对油酸非常敏感，而缺失ELO1的菌株的生长没有变化，这与C ₁₄脂肪酸（FA）向C的延伸有关。₁₆F A。通过使用GC-MS，用油酸（OLA）处理后，elo2△和elo3△突变体的不饱和指数增加。然而，在野生型菌株中，响应于OLA，VLCFA的比例增加。elo2△和elo3△的生长抑制可以通过两种常用的抗氧化剂N-乙酰半胱氨酸（NAC）和抗坏血酸（VC）部分拯救。进一步的研究表明，暴露于过量的OLA会导致野生型和活性型中活性氧（ROS）和硫代巴比妥酸反应性物质（TBARS）的含量增加，还原型谷胱甘肽（GSH）的含量下降。突变株。然而，用过量的OLA处理后，野生型和elo1△菌株中超氧化物歧化酶（SOD）和过氧化氢酶（CAT）的抗氧化酶活性增加，而在elo2△和elo3△突变体中则显着降低。因此，氧化损伤主要是由于ole2△和ole3△中的OLA引起的细胞死亡。。两者合计，尽管破坏ELO2或ELO3不会影响细胞脂质不饱和度，但它们改变了细胞VLCFA的分布和比例，导致细胞膜受损，从而增强了OLA透化质膜的能力。数据表明，非常长链的脂肪酸延伸酶ELO2和ELO3通过维持质膜中FA成分的平衡，在OLA诱导的脂毒性细胞死亡中发挥重要作用。