Interactions of glutathione, reactive oxygen species, and lipids on oocyte mitochondrial function

项目摘要/摘要 成熟的卵母细胞内含有最高浓度的有效抗氧化剂谷胱甘肽。 (GSH)。缺乏谷氨酸半胱氨酸连接酶(GCLM)修饰亚基的雌性小鼠 GSH合成中的酶，卵母细胞中GSH浓度低，卵子质量差，表现为 胚胎死亡率在胚泡阶段之前增加，慢性卵巢氧化应激，并加速 青春期后，与年龄相关的原始卵泡池下降，这构成了不可替代的卵巢 保留。因此，与许多转基因小鼠模型相比，这些模型拥有完整的卵巢 在青春期前卵泡耗尽，这些小鼠更接近于模拟病理条件 人类的卵巢储备。雌性Gclm基因缺失小鼠也对与饮食和年龄相关的身体增长具有抵抗力 体重和脂肪组织，降低了肝脏脂肪生成基因的表达，并有所增加 肝线粒体耗氧量；然而，Gclm缺失对卵母细胞脂代谢的影响 线粒体的功能还没有被研究过。因此，GCLM缺失小鼠构成了一个很好的模型，在该模型中 GSH缺乏引起卵母细胞线粒体功能障碍的假说 直接损伤线粒体大分子和/或通过脂肪生成减少的活性氧物种 导致卵母细胞线粒体脂肪酸β氧化减少。这一假设将通过两个方面进行检验 具体目标：1)确定由于Gclm缺失导致的卵母细胞GSH缺乏是否会导致卵母细胞增加 线粒体ROS生成，线粒体氧化脂质和DNA损伤，线粒体减少 功能。2)评估Gclm缺乏对血清和卵母细胞脂类的影响以及对脂肪生成和 卵母细胞中的脂肪酸β氧化。拟议的研究将解决理解方面的知识差距。 卵巢储备减少与卵母细胞质量差之间的关系 卵母细胞线粒体的损伤和卵母细胞脂平衡的破坏在机制上参与了 Gclm-/-小鼠的卵母细胞质量下降。

PROJECT SUMMARY/ABSTRACT Mature oocytes have among the highest intracellular concentrations of the potent antioxidant glutathione (GSH). Female mice lacking the modifier subunit of glutamate cysteine ligase (GCLM), the rate-limiting enzyme in GSH synthesis, have low GSH concentrations in oocytes, poor oocyte quality that manifests as increased embryonic mortality prior to the blastocyst stage, chronic ovarian oxidative stress, and accelerated post-pubertal, age-related decline in the primordial follicle pool, which constitutes the irreplaceable ovarian reserve. Therefore, compared to many genetically modified mouse models, which have complete ovarian follicle depletion prior to puberty, these mice more closely model pathological conditions with diminished ovarian reserve in humans. Female Gclm null mice are also resistant to diet- and age-associated gains in body weight and adipose tissue, have decreased hepatic expression of lipogenesis genes, and have increased hepatic mitochondrial oxygen consumption; however, the effects of Gclm deletion on oocyte lipid metabolism and mitochondrial function have not been studied. Gclm null mice thus constitute an excellent model in which to investigate the hypothesis that GSH deficiency causes oocyte mitochondrial dysfunction via increased reactive oxygen species that directly damage mitochondrial macromolecules and/or via decreased lipogenesis resulting in decreased oocyte mitochondrial fatty acid beta oxidation. This hypothesis will be tested via two specific aims: 1) Determine whether oocyte GSH deficiency due to Gclm deletion results in increased oocyte mitochondrial ROS generation, mitochondrial oxidative lipid and DNA damage, and decreased mitochondrial function. 2) Assess the effects of Gclm deficiency on the serum and oocyte lipidomes and on lipogenesis and fatty acid beta oxidation in the oocyte. The proposed studies will address the knowledge gap in understanding the association between decreased ovarian reserve and poor oocyte quality by examining whether oxidative damage to oocyte mitochondria and disruption of oocyte lipid homeostasis are mechanistically involved in decreased oocyte quality in Gclm-/- mice.