线粒体自噬基因对酿酒酵母抗氧化性能的影响

Effect of mitophagy related genes on the antioxidant properties of Saccharomyces cerevisiae

摘要:

线粒体自噬是指细胞通过自噬的机制选择性地清除线粒体的过程，对维持细胞内稳态具有重要作用。为探究线粒体自噬基因对酿酒酵母(Saccharomyces cerevisiae)细胞抗氧化性能的影响，本研究分别构建了线粒体自噬相关基因ATG8、ATG11、ATG32的缺失和过表达菌株，发现在过氧化氢(H₂O₂)胁迫6 h后，过表达ATG8、ATG11基因显著降低了细胞内活性氧(reactive oxygen species,ROS)含量，分别仅为初始状态的61.23%和46.35%，并显著提高了菌株线粒体膜电位(mitochondrial membrane potential,MMP)和腺嘌呤核苷三磷酸(adenosine-triphosphate,ATP)含量，有助于提高菌株的抗氧化性能。另一方面，基因ATG8、ATG11、ATG32的缺失会导致线粒体损伤及细胞活力显著下降，同时造成胞内ROS失衡，H₂O₂胁迫6 h后，其胞内ROS含量显著升高至初始状态的174.27%、128.68%和200.92%。结果表明，ATG8、ATG11和ATG32可能是调控酵母抗氧化能力的潜在靶点。本研究为进一步研究通过调节线粒体自噬提高酵母抗氧化活性提供了新的线索。

Abstract:

Mitophagy is a process whereby cells selectively remove mitochondria through the mechanism of autophagy, which plays an important role in maintaining cellular homeostasis. In order to explore the effect of mitophagy genes on the antioxidant activities of Saccharomyces cerevisiae, mutants with deletion or overexpression of mitophagy genes ATG8, ATG11 and ATG32 were constructed respectively. The results indicated that overexpression of ATG8 and ATG11 genes significantly reduced the intracellular reactive oxygen species (ROS) content upon H₂O₂ stress for 6 h, which were 61.23% and 46.35% of the initial state, respectively. Notable, overexpression of ATG8 and ATG11 genes significantly increased the mitochondrial membrane potential (MMP) and ATP content, which were helpful to improve the antioxidant activities of the strains. On the other hand, deletion of ATG8, ATG11 and ATG32 caused mitochondrial damage and significantly decreased cell vitality, and caused the imbalance of intracellular ROS. The intracellular ROS content significantly increased to 174.27%, 128.68%, 200.92% of the initial state, respectively, upon H₂O₂ stress for 6 h. The results showed that ATG8, ATG11 and ATG32 might be potential targets for regulating the antioxidant properties of yeast, providing a new clue for further research.