PDF(Pubmed)
Abstract：
Global methylation levels differ in in vitro- and in vivo-developed embryos. Follicular fluid (FF) contains extracellular vesicles (EVs) containing miRNAs that affect embryonic development. Here, we examined our hypothesis that components in FF affect global DNA methylation and embryonic development. Oocytes and FF were collected from bovine ovaries. Treatment of zygotes with a low concentration of FF induced global DNA demethylation, improved embryonic development, and reduced DNMT1/3A levels. We show that embryos take up EVs containing labeled miRNA secreted from granulosa cells and the treatment of zygotes with EVs derived from FF reduces global DNA methylation in embryos. Furthermore, the methylation levels of in vitro-developed blastocysts were higher than those of in their vivo counterparts. Based on small RNA-sequencing and in silico analysis, we predicted miR-29b, -199a-3p, and -148a to target DNMTs and to induce DNA demethylation, thereby improving embryonic development. Moreover, among FF from 30 cows, FF with a high content of these miRNAs demethylated more DNA in the embryos than FF with a lower miRNA content. Thus, miRNAs in FF play a role in early embryonic development.
摘要：
全球甲基化水平在体外和体内发育的胚胎中不同。卵泡液(FF)包含含有影响胚胎发育的miRNA的细胞外囊泡(EV)。这里,我们检验了我们的假设，即FF中的成分会影响全局DNA甲基化和胚胎发育。从牛卵巢收集卵母细胞和FF。用低浓度的FF处理受精卵诱导的全局DNA去甲基化，改善胚胎发育，降低DNMT1/3A水平。我们表明，胚胎吸收含有颗粒细胞分泌的标记miRNA的EV，并且用FF衍生的EV处理受精卵会减少胚胎中的整体DNA甲基化。此外，体外发育囊胚的甲基化水平高于体内发育囊胚的甲基化水平.基于小RNA测序和计算机模拟分析，我们预测miR-29b,-199a-3p，和-148a靶向DNMT并诱导DNA去甲基化，从而改善胚胎发育。此外，在30头牛的FF中，与miRNA含量较低的FF相比，这些miRNA含量较高的FF使胚胎中更多的DNA去甲基化。因此，FF中的miRNA在早期胚胎发育中起作用。
