National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China.
Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou, 510642, China.
BMC Genomics. 2023 Jul 24;24(1):412. doi: 10.1186/s12864-023-09414-1.
One of the most critical periods for the loss of pig embryos is the 12th day of gestation when implantation begins. Recent studies have shown that non-coding RNAs (ncRNAs) play important regulatory roles during pregnancy. Circular RNAs (circRNAs) are a kind of ubiquitously expressed ncRNAs that can directly regulate the binding proteins or regulate the expression of target genes by adsorbing micro RNAs (miRNA).
We used the Illumina Novaseq6,000 technology to analyze the circRNA expression profile in the endometrium of three Erhualian (EH12) and three Yorkshire (YK12) pigs on day 12 of gestation. Overall, a total of 22,108 circRNAs were identified. Of these, 4051 circRNAs were specific to EH12 and 5889 circRNAs were specific to YK12, indicating a high level of breed specificity. Further analysis showed that there were 641 significant differentially expressed circRNAs (SDEcircRNAs) in EH12 compared with YK12 (FDR < 0.05). Functional enrichment of differential circRNA host genes revealed many pathways and genes associated with reproduction and regulation of embryo development. Network analysis of circRNA-miRNA interactions further supported the idea that circRNAs act as sponges for miRNAs to regulate gene expression. The prediction of differential circRNA binding proteins further explored the potential regulatory pathways of circRNAs. Analysis of SDEcircRNAs suggested a possible reason for the difference in embryo survival between the two breeds at the peri-implantation stage.
Together, these data suggest that circRNAs are abundantly expressed in the endometrium during the peri-implantation period in pigs and are important regulators of related genes. The results of this study will help to further understand the differences in molecular pathways between the two breeds during the critical implantation period of pregnancy, and will help to provide insight into the molecular mechanisms that contribute to the establishment of pregnancy and embryo loss in pigs.
胚胎丢失最关键的时期之一是妊娠第 12 天，此时开始着床。最近的研究表明，非编码 RNA（ncRNA）在妊娠期间发挥重要的调节作用。环状 RNA（circRNA）是一种广泛表达的 ncRNA，可以直接调节结合蛋白，或通过吸附 micro RNA（miRNA）来调节靶基因的表达。
我们使用 Illumina Novaseq6000 技术分析了妊娠第 12 天的 3 头长白猪（EH12）和 3 头约克夏猪（YK12）子宫内膜中的 circRNA 表达谱。总的来说，共鉴定出 22108 个 circRNA。其中，4051 个 circRNA 是 EH12 特异性的，5889 个 circRNA 是 YK12 特异性的，表明品种特异性很高。进一步分析表明，EH12 与 YK12 相比有 641 个差异表达 circRNA（SDEcircRNA）（FDR<0.05）。差异 circRNA 宿主基因的功能富集分析显示，许多与繁殖和胚胎发育调控相关的途径和基因。circRNA-miRNA 相互作用网络分析进一步支持了 circRNA 作为 miRNA 海绵调节基因表达的观点。差异 circRNA 结合蛋白的预测进一步探索了 circRNA 潜在的调节途径。SDEcircRNA 的分析表明，这两个品种在着床期胚胎存活率的差异可能有其原因。
综上所述，这些数据表明，circRNA 在猪着床期子宫内膜中大量表达，是相关基因的重要调节因子。本研究的结果将有助于进一步了解这两个品种在妊娠关键着床期分子途径的差异，并有助于深入了解导致猪妊娠和胚胎丢失的分子机制。
