Table 2_Effects of light exposure during IVF: transcriptomic analysis of murine embryos and embryo-derived EVs.xlsx

IntroductionLight exposure of embryos during assisted reproduction affects embryo quality and implantation capacity in a wavelength dependent manner. We investigated the molecular mechanism of these light-induced changes through the comparative analysis of gene expression and regulatory miRNA profile of murine embryos cultured in dark environment and those exposed to white- or red filtered light. miRNA sequencing was used to assess the role of embryo-derived extracellular vesicles in the endometrium-embryo dialogue.
MethodsIn vitro cultured mouse embryos at 3.5 days post coitum (dpc) were exposed to white or red filtered light. After 24 hours mRNA and miRNA content of the embryos as well as the miRNA content of embryo-derived extracellular vesicles were isolated and RNA-sequencing was performed. Differential expression analysis and functional enrichment analysis were used for evaluating the transcriptome results.
ResultsLight exposure caused transcriptomic changes in the embryos. White light upregulated apoptotic pathways, while red filtered light gave rise to the activation of regeneration pathways, including DNA repair mechanisms. Embryo-derived extracellular vesicles enclosed wavelength dependently unique miRNA cargos the target genes of which play a role in embryo implantation.
DiscussionWhite light upregulates apoptotic pathways, at both the transcriptome and regulatory miRNAs levels. Red filtration partially counterbalances these negative effects by shifting the cellular processes towards regeneration, including DNA repair mechanisms. Extracellular vesicles of light exposed embryos play a role in blastocyst-decidua communication through the horizontal transfer of regulatory miRNAs. Our data prove that light exposure during in vitro fertilization modifies cell function that might affect the outcome of implantation.

引言
辅助生殖（assisted reproduction）过程中对胚胎进行光照暴露，会以波长依赖的方式影响胚胎质量与着床能力。本研究通过对比分析黑暗环境培养、白光照射或红光滤光照射的小鼠胚胎的基因表达谱与调控性miRNA（microRNA）表达谱，探究这类光照诱导变化的分子机制；同时采用miRNA测序，评估胚胎源性细胞外囊泡（embryo-derived extracellular vesicles）在子宫内膜与胚胎互作中的作用。
方法
选取交配后3.5天（days post coitum，简称dpc）的体外培养小鼠胚胎，分别接受白光或红光滤光照射。培养24小时后，提取胚胎的mRNA、miRNA以及胚胎源性细胞外囊泡的miRNA，并进行RNA测序（RNA-sequencing）。采用差异表达分析与功能富集分析对转录组结果进行评估。
结果
光照暴露可引发胚胎的转录组变化。白光可上调凋亡通路，而红光滤光照射则激活包括DNA修复机制在内的再生通路。胚胎源性细胞外囊泡携带具有波长依赖性的独特miRNA载荷，其靶基因参与胚胎着床过程。
讨论
白光可在转录组与调控性miRNA两个层面上调凋亡通路。红光滤光处理可通过将细胞进程转向包括DNA修复在内的再生通路，部分抵消上述负面影响。光照暴露胚胎的细胞外囊泡可通过水平传递调控性miRNA，参与囊胚与蜕膜之间的信息交流。本研究数据证实，体外受精过程中的光照暴露会改变细胞功能，进而可能影响着床结局。