Changes in circulating microRNA levels can be identified as early as day 8 of pregnancy in cattle.
Changes in circulating microRNA levels can be identified as early as day 8 of pregnancy in cattle.
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牛怀孕第 8 天就可以识别循环 microRNA 水平的变化。
DOI：
10.1371/journal.pone.0174892
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发表时间：
2017
期刊：
影响因子：
3.7
通讯作者：
Donadeu FX
中科院分区：
文献类型：
--
作者：
Ioannidis J;Donadeu FX
繁殖性能差仍然是乳制品行业的一个主要问题，低受孕率通过延长产犊间隔对产奶量产生重大影响。一个主要的限制因素是缺乏可靠的早孕诊断方法。在授精后3周内识别畜群中未能受孕的动物将允许早期再授精并缩短产犊间隔。在先前的研究中，我们发现相对于未怀孕的小母牛，怀孕第16天的血浆miR-26 a水平增加，然而在怀孕早期miRNA水平的变化非常小，这可能阻碍了稳健生物标志物的鉴定。在这项研究中，我们将我们的分析扩展到妊娠期间更宽的时间间隔（第8天至第60天，n = 11头小母牛），理由是这可能有助于鉴定其他早孕miRNA生物标志物。使用小RNA测序，我们确定了77个miRNAs，这些miRNAs在妊娠第60天相对于妊娠第0天差异表达。我们选择了14种miRNA通过RT-qPCR进行验证，并证实了第0天和第60天之间let-7 f、let-7 c、miR-30 c、miR-101、miR-26 a、miR-205和miR-143的表达存在显著差异。整个妊娠第0、8、16和60天的RT-qPCR分析显示，早在妊娠第8天，miR-26 a的循环水平就明显增加（3.1倍，P = 0.046）。总之，与妊娠早期（≤第24天）相比，到第60天，在牛的循环中可检测到多种miRNA水平的显著差异。回顾性分析显示，早在第8天，循环中的miR-26 a水平就增加了，比以前在任何物种中报道的都要快，这表明这种miRNA在妊娠早期事件中的生物学作用。
Poor reproductive performance remains a major issue in the dairy industry, with low conception rates having a significant impact on milk production through extended calving intervals. A major limiting factor is the lack of reliable methods for early pregnancy diagnosis. Identification of animals within a herd that fail to conceive within 3 weeks after insemination would allow early re-insemination and shorten calving intervals. In a previous study, we found an increase in plasma miR-26a levels in Day 16-pregnant relative to non-pregnant heifers, however changes in miRNA levels that early during pregnancy were very small which likely prevented the identification of robust biomarkers. In this study, we extended our analyses to a wider interval during pregnancy (Days 8 to 60, n = 11 heifers) with the rationale that this may facilitate the identification of additional early pregnancy miRNA biomarkers. Using small RNA sequencing we identified a total of 77 miRNAs that were differentially expressed on Day 60 relative to Day 0 of pregnancy. We selected 14 miRNAs for validation by RT-qPCR and confirmed significant differences in the expression of let-7f, let-7c, miR-30c, miR-101, miR-26a, miR-205 and miR-143 between Days 0 and 60. RT-qPCR profiling throughout Days 0, 8, 16 and 60 of pregnancy showed a distinct increase in circulating levels of miR-26a (3.1-fold, P = 0.046) as early as Day 8 of pregnancy. In summary, in contrast to earlier stages of pregnancy (≤ Day 24), marked differences in the levels of multiple miRNAs can be detected in circulation by Day 60 in cattle. Retrospective analyses showed miR-26a levels to be increased in circulation as early as Day 8, sooner than previously reported in any species, suggesting a biological role for this miRNA in the very early events of pregnancy.