State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, Suzhou Affiliated Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Nanjing, China.
Department of Clinical Nursing, School of Nursing, Nanjing Medical University, Nanjing, China.
Aging Cell. 2021 Oct;20(10):e13482. doi: 10.1111/acel.13482. Epub 2021 Sep 28.
Aging has many effects on the female reproductive system, among which decreased oocyte quality and impaired embryo developmental potential are the most important factors affecting female fertility. However, the mechanisms underlying oocyte aging are not yet fully understood. Here, we selected normal reproductively aging female mice and constructed a protein expression profile of metaphase II (MII) oocytes from three age groups. A total of 187 differentially expressed (DE) proteins were identified, and bioinformatics analyses showed that these DE proteins were highly enriched in RNA splicing. Next, RNA-seq was performed on 2-cell embryos from these three age groups, and splicing analysis showed that a large number of splicing events and genes were discovered at this stage. Differentially spliced genes (DSGs) in the two reproductively aging groups versus the younger group were enriched in biological processes related to DNA damage repair/response. Binding motif analysis suggested that PUF60 might be one of the core splicing factors causing a decline in DNA repair capacity in the subsequent development of oocytes from reproductively aging mice, and changing the splicing pattern of its potential downstream DSG Cdk9 could partially mimic phenotypes in the reproductively aging groups. Taken together, our study suggested that the abnormal expression of splicing regulation proteins in aged MII oocytes would affect the splicing of nascent RNA after zygotic genome activation in 2-cell embryos, leading to the production of abnormally spliced transcripts of some key genes associated with DNA damage repair/response, thus affecting the developmental potential of aged oocytes.
衰老是女性生殖系统的许多影响，其中卵母细胞质量下降和胚胎发育潜能受损是影响女性生育力的最重要因素。然而，卵母细胞衰老的机制尚不完全清楚。在这里，我们选择了正常生殖衰老的雌性小鼠，并构建了来自三个年龄组的中期 II (MII) 卵母细胞的蛋白质表达谱。共鉴定出 187 个差异表达 (DE) 蛋白，生物信息学分析表明这些 DE 蛋白高度富集在 RNA 剪接中。接下来，对来自这三个年龄组的 2 细胞胚胎进行了 RNA-seq 分析，剪接分析表明在这个阶段发现了大量的剪接事件和基因。两个生殖衰老组与年轻组的差异剪接基因 (DSG) 在与 DNA 损伤修复/反应相关的生物学过程中富集。结合基序分析表明 PUF60 可能是导致生殖衰老小鼠卵母细胞随后发育中 DNA 修复能力下降的核心剪接因子之一，改变其潜在下游 DSG Cdk9 的剪接模式可以部分模拟生殖衰老组的表型。总之，我们的研究表明，衰老 MII 卵母细胞中剪接调控蛋白的异常表达会影响 2 细胞胚胎中合子基因组激活后新生 RNA 的剪接，导致与 DNA 损伤修复/反应相关的一些关键基因的异常剪接转录本的产生，从而影响衰老卵母细胞的发育潜能。
