Age-related changes in the mitochondria of human mural granulosa cells
Age-related changes in the mitochondria of human mural granulosa cells
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DOI：
10.1093/humrep/dex309
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发表时间：
2017-12-01
影响因子：
6.1
通讯作者：
Yao, Yuanqing
中科院分区：
文献类型：
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作者：
Liu, Yifan;Han, Ming;Yao, Yuanqing
研究问题：随着母亲年龄的增长，人壁颗粒细胞（mGC）的线粒体发生了什么变化？总结回答：随着生殖年龄的增长，mGCs的线粒体膜电位（mitochondrial membrane potential，MMP）和氧化磷酸化（oxidative phosphorylation，OXPHOS）能力下降，线粒体异常增多。研究设计规模、持续时间：2016年9月至2017年5月，共有149名不孕妇女在中国人民解放军总医院ART中心接受IVF。调查了两个年龄组：青年组（< 38岁）和老年组（>= 38岁）。参与者/材料，地点，方法：透射电镜观察mGCs线粒体超微结构，实时荧光定量聚合酶链反应检测线粒体DNA拷贝数，线粒体ATP酶ATP 5A 1和ATP 5I的4977-bp缺失DNA和mRNA表达。采用流式细胞仪和荧光显微镜分别检测MMP的表达。流式细胞仪检测细胞内活性氧（ROS）水平。主要结果和机会的作用：青年组线粒体多呈圆形或卵圆形，有少量完整的平行管状-泡状嵴，基质密度均匀;老年组线粒体多呈细长形，嵴多，基质密度高。线粒体异常在老年妇女中更常见（P = 0.012）。mtDNA相对拷贝数与母亲年龄呈正相关（r = 0.294，P = 0.009），未发现4977 bp缺失的线粒体。老年组的JC-1（用作MMP指标的染料）比率明显低于年轻组（3.01 +/- 0.21 vs 3.85 +/- 0.27，P = 0.033）。两组间细胞内ROS水平无显著差异（P = 0.191）。年轻组细胞内ATP水平是高龄组的1.75倍（7.17 ± 1.16 vs 4.15 ± 0.60，P = 0.025）。OXPHOS 5种蛋白之一的ATP 5A 1蛋白表达随增龄而降低（P < 0.001）。ATP 5A 1 mRNA表达与增龄呈负相关（r =-0.341，P = 0.012）。局限性原因：个别患者，尤其是高龄患者，mGCs数量较少，不能满足所有检测的要求。提高mGCs的OXPHOS能力是解决高龄不孕症的关键，也是使mGCs成为自体线粒体移植卵母细胞的合适线粒体供体细胞的关键。
STUDY QUESTION: What changes in the mitochondria of human mural granulosa cells (mGCs) with maternal aging?SUMMARY ANSWER: The mitochondrial membrane potential (MMP) and the ability of oxidative phosphorylation (OXPHOS) of mGCs declines with reproductive aging, accompanied with more abnormal mitochondria.WHAT IS KNOWN ALREADY: Mitochondria play an important role in the dialogue between the mGCs and oocytes. However, the underlying mechanism of mitochondrial dysfunction in mGCs in aging is still poorly understood.STUDY DESIGN SIZE, DURATION: In total, 149 infertile women underwent IVF in the ART Centre of the Chinese PLA General Hospital, China from September 2016 to May 2017. Two age groups were investigated: the young group (< 38 years old) and the old group (>= 38 years old).PARTICIPANTS/MATERIALS, SETTING, METHODS: The mitochondrial ultrastructure of mGCs was observed by transmission electron microscopy, and real-time quantitative polymerase chain reaction was applied to quantify the mitochondrial DNA (mtDNA) copy number, 4977-bp deleted DNA and mRNA expression of mitochondrial ATP synthases ATP5A1 and ATP5I. MMP was detected by flow cytometry and fluorescence microscopy, respectively. Reactive oxygen species (ROS) was tested by flow cytometry. A luminometer was used to measure the ATP levels and western blot to analyse the OXPHOS complex.MAIN RESULTS AND THE ROLE OF CHANCE: In the young group, mitochondria were mostly round or oval, with a few intact parallel tubular- vesicular cristae and homogenous matrix density, while elongated mitochondria were mainly observed in the old group, which had numerous cristae and more high-density matrix particles. Abnormal mitochondria were more common in aging women (P = 0.012). mtDNA relative copy number was positively correlated with maternal age (r = 0.294, P = 0.009) and we found no one with 4977-bp deleted mitochondria. JC-1 (dye used as an indicator of MMP) ratio in the old group was significantly lower than the young group (3.01 +/- 0.21 vs 3.85 +/- 0.27, P = 0.033). Intracellular ROS levels between the groups did not differ significantly (P = 0.191). The intracellular ATP level in the young group was 1.75-fold higher than that of the advanced- age group (7.17 +/- 1.16 vs 4.15 +/- 0.60, P = 0.025). The protein expression of ATP5A1, as one of five proteins of OXPHOS, decreased with aging (P < 0.001). ATP5A1 mRNA expression was negatively correlated with aging (r = -0.341, P = 0.012).LIMITATIONS REASONS FOR CAUTION: The quantity of mGCs from some individual patient, especially an advanced-age individual, was small, which cannot meet the demands of all the detections.WIDER IMPLICATIONS OF THE FINDINGS: mGCs dysfunction with aging is mainly linked to impaired mitochondrial function, especially OXPHOS function. Improving the OXPHOS ability in mGCs should be the focus in resolving infertility among advanced age women and making mGCs the proper mitochondria donor cells in the autologous mitochondria transplantation to oocytes.