Nonesterified Fatty Acid-Induced Endoplasmic Reticulum Stress in Cattle Cumulus Oocyte Complexes Alters Cell Metabolism and Developmental Competence
Nonesterified Fatty Acid-Induced Endoplasmic Reticulum Stress in Cattle Cumulus Oocyte Complexes Alters Cell Metabolism and Developmental Competence
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DOI：
10.1095/biolreprod.115.131862
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发表时间：
2016-01-01
影响因子：
3.6
通讯作者：
Robker, Rebecca L.
中科院分区：
文献类型：
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作者：
Sutton-McDowall, Melanie L.;Wu, Linda L. Y.;Robker, Rebecca L.
由于能量负平衡，在泌乳高峰期，卵母细胞质量下降与高性能奶牛的生育力低下有关。我们研究了非酯化脂肪酸（NEFAs）的作用，已知在营养不良和营养过剩的情况下，在卵泡液中积累，在体外成熟的牛卵丘卵母细胞复合体（COCs）引起内质网（ER）应激。NEFA浓度为：棕榈酸（150 μ M）、油酸（200 μ M）和硬脂酸（75 μ M）。屠宰场衍生的COCs随机成熟24小时的NEFA和/或ER应激抑制剂，salubrinal的存在下。与对照组相比，NEFA处理对总囊胚产量和孵化囊胚产量产生了负面影响，但salubrinal逆转了这一点。ER应激标志物，转录激活因子4（Atf 4）和热休克蛋白5（Hspa 5），但不Atf 6，显着上调NEFA治疗内的整个COCs，但逆转与salubrinal共孵育。同样，在用过的培养基样品中测量的葡萄糖摄取和乳酸产生显示出类似的模式，表明卵丘细胞代谢通过ER应激介导的过程对NEFA敏感。相比之下，虽然NEFA处理的卵母细胞中线粒体DNA拷贝数恢复，但COC的NEFA处理后，呼吸链辅因子FAD的卵母细胞自发荧光较低，并且这未被salubrinal逆转，表明负面影响是通过线粒体功能降低。这些结果揭示了NEFA诱导的ER应激对牛COC发育能力的意义，揭示了在泌乳高峰期改善卵母细胞质量的潜在治疗靶点。
Reduced oocyte quality has been associated with poor fertility of high-performance dairy cows during peak lactation, due to negative energy balance. We examined the role of nonesterified fatty acids (NEFAs), known to accumulate within follicular fluid during under- and overnutrition scenarios, in causing endoplasmic reticulum (ER) stress of in vitro maturated cattle cumulusoocyte complexes (COCs). NEFA concentrations were: palmitic acid (150 mu M), oleic acid (200 iuM), and steric acid (75 iuM). Abattoir-derived COCs were randomly matured for 24 h in the presence of NEFAs and/or an ER stress inhibitor, salubrinal. Total and hatched blastocyst yields were negatively impacted by NEFA treatment compared with controls, but this was reversed by salubrinal. ER stress markers, activating transcription factor 4 (Atf4) and heat shock protein 5 (Hspa5), but not Atf6, were significantly up-regulated by NEFA treatment within whole COCs but reversed by coincubation with salubrinal. Likewise, glucose uptake and lactate production, measured in spent medium samples, showed a similar pattern, suggesting that cumulus cell metabolism is sensitive to NEFAs via an ER stress mediated process. In contrast, while mitochondrial DNA copy number was recovered in NEFA-treated oocytes, oocyte autofluorescence of the respiratory chain cofactor, FAD, was lower following NEFA treatment of COCs, and this was not reversed by salubrinal, suggesting the negative impact was via reduced mitochondrial function. These results reveal the significance of NEFA-induced ER stress on bovine COC developmental competence, revealing a potential therapeutic target for improving oocyte quality during peak lactation.