Mitochondrial RNA defense pathways in the oocyte

摘要 母体衰老对卵母细胞的质量和能力有显著影响，众所周知， 线粒体功能在卵母细胞健康中起重要作用。转录后的基因调控 卵母细胞对其正常发育和功能也是必不可少的。在体细胞中，线粒体是关键 转录后基因调控的效应子，其中位于线粒体上的RNA传感器在转录后基因调控中起作用。 双链RNA（dsRNA）的反应，以调用线粒体RNA防御途径。的作用 线粒体防御途径，包括RNA编辑和RNA传感是未知的卵母细胞，甚至 尽管卵母细胞内有丰富的dsRNA。在这里，我们提供了初步的数据，证明了 小鼠和人类卵母细胞中丰富的RNA编辑，作用于 RNA'（阿达尔），以及小鼠和人卵母细胞中RNA传感途径的下游组分。 最重要的是，我们发现，卵母细胞中阿达尔RNA编辑的抑制导致ADAR的积累增加。 活性氧（ROS），因此涉及RNA编辑作为线粒体功能的调节剂， 可能是卵母细胞的质量最后，来自生育年龄大的老鼠的数据表明，参与RNA的基因 编辑（ADAR 1）和RNA传感（p32）在卵母细胞中减少，因此可能导致异常的 线粒体RNA依赖的防御途径的激活。我们认为卵母细胞线粒体是关键 卵母细胞内的RNA编辑和RNA传感机制的效应子，在诸如老化的条件下， 线粒体RNA防御过度可能增加ROS积累并最终影响卵母细胞 质量.我们打算在这个提议中测试的中心假设是，线粒体RNA防御 信号通路是卵母细胞能力/质量的关键调节因子。为了检验中心假设，具体目标1 将鉴定三种哺乳动物卵母细胞中发生的特定卵母细胞RNA编辑。具体目标2将 确定ADAR 1和RIG-I/MAVS在卵母细胞线粒体功能调节中的作用， 最先进的线粒体功能测定，并评估对卵母细胞质量/发育的影响 潜力具体目标3将研究高龄生育如何影响线粒体RNA传感 在小鼠和人类卵母细胞中的通路。最终，这项工作可能会提供一个机械连接（dsRNA）， 防御途径），可以解释已知的线粒体功能障碍与卵母细胞从 生殖年龄大的小鼠和年龄大的IVF患者。

Abstract Maternal aging has dramatic effects on the oocyte quality and competence, and it is well known that mitochondrial function plays important roles in oocyte health. Post-transcriptional gene regulation within the oocyte is also essential for its normal development and function. In somatic cells, mitochondria are key effectors of post-transcriptional gene regulation, where RNA sensors located on the mitochondria react in response to double stranded RNA (dsRNA) to invoke the mitochondrial RNA defense pathway. The role of the mitochondrial defense pathway, which includes RNA-editing and RNA sensing is unknown in the oocyte, even though the oocyte has an abundance of dsRNA within it. Here we provide preliminary data demonstrating an abundance of RNA edits in mouse and human oocytes, the expression of `adenosine deaminase acting on RNA' (ADAR), as well as downstream components of the RNA sensing pathway in mouse and human oocytes. Most importantly, we show that inhibition of ADAR RNA editing in oocytes results in increased accumulation of reactive oxygen species (ROS), thus implicating RNA editing as a regulator of mitochondrial function and possibly oocyte quality. Lastly, data from reproductively old mice indicate that the genes involved in RNA editing (ADAR1) and RNA sensing (p32) are decreased in oocytes, thus potentially leading to aberrant activation of mitochondrial RNA-dependent defense pathway. We propose that oocyte mitochondria are key effectors of the RNA editing and RNA sensing mechanisms within oocytes, under conditions such as aging, hyper-activity of mitochondrial RNA defense may increase ROS accumulation and ultimately impact oocyte quality. The central hypothesis we intend to test in this proposal is that the mitochondrial RNA defense pathway is a critical regulator of oocyte competence/quality. To test the central hypothesis, Specific Aim 1 will identify the specific oocyte RNA edits occurring in three species of mammalian oocytes. Specific Aim 2 will determine the role of ADAR1 and RIG-I/MAVS in the regulation of mitochondrial function in oocytes using state-of-the-art mitochondrial functional assays and assess the impact on oocyte quality/developmental potential. Specific Aim 3 will examine how advanced reproductive age impacts mitochondrial RNA sensing pathways in both mouse and human oocytes. Ultimately, this work may provide a mechanistic link (dsRNA defense pathway) that can explain the known mitochondrial dysfunction associated with oocytes from reproductively old mice and older IVF patients.