Pregnancy-associated genes contribute to antiluteolytic mechanisms in ovine coprus luteum

Ovine interferon-tau (IFNT) is released from the conceptus by Day 12 of pregnancy and disrupts pulsatile release of endometrial prostaglandin F2 alpha (PGF), thereby protecting the corpus luteum (CL). IFNT may also have endocrine action through inducing interferon stimulated genes (ISGs) in the CL. The hypothesis that gene expression differs in CL collected from pregnant (P) and non-pregnant (NP) ewes by Day 14 due to the lytic action of PGF during the estrous cycle or the presence of a conceptus was tested. RNA was isolated on Days 12 and 14 in NP or P ewes (n = 3 ewes/group) and analyzed using the Affymetrix bovine microarray (24,000 targets). Differential gene expression (>1.5 fold, P < 0.05) was confirmed using semi-quantitative real time PCR (RTPCR). Serum progesterone concentrations decreased (P < 0.05) from 1.7 ng/ml on Day 12 to 1.3 ng/ml by Day 14 in NP ewes suggesting initiation of luteolysis; and remained > 1.7 ng/ml in Day 12 and 14 P ewes indicating that the conceptus protected the CL from luteolysis. Early luteolysis from Day 12 to 14 NP was associated with differential expression of 683 genes, including SERPINE1 and THBS1. Presence of a conceptus from Day 12 to 14 also induced expression of 743 genes, i.e., ISGs (ISG15, MX1), PTX3, and IL-6 and stabilized expression of VEGF and LHR genes. In conclusion, pregnancy circumvents luteolytic pathways, and activates or stabilizes genes associated with interferon, chemokine, cell adhesion, cytoskeletal, angiogenic and epithelial to mesynchymal transition pathways in the CL. There are 12 samples that were analyzed for the microarray, no duplicates and we increased the sample size to 50 for the RTPCR. This Series contains the Affymetrix array data only (not RT-PCR data).

绵羊干扰素τ（ovine interferon-tau, IFNT）于妊娠第12天由孕体释放，可抑制子宫内膜前列腺素F2α（endometrial prostaglandin F2 alpha, PGF）的脉冲式释放，从而保护黄体（corpus luteum, CL）。IFNT还可通过在黄体中诱导干扰素刺激基因（interferon stimulated genes, ISGs）发挥内分泌功能。
本研究针对“由于发情周期中PGF的溶黄体作用，或是孕体的存在，妊娠组（P）与非妊娠组（NP）母羊在第14天时的黄体基因表达存在差异”这一假说开展验证。
研究人员于妊娠组与非妊娠组母羊的第12天和第14天分离RNA（每组3只母羊），采用Affymetrix牛基因芯片（包含24000个靶标）进行转录组分析。对于筛选得到的差异表达基因（表达倍数变化>1.5倍，P<0.05），通过半定量实时PCR（semi-quantitative real time PCR, RT-PCR）进行验证。
非妊娠组母羊的血清孕酮浓度从第12天的1.7 ng/ml降至第14天的1.3 ng/ml（P<0.05），提示黄体溶解启动；而妊娠组母羊第12天和第14天的血清孕酮浓度均维持在1.7 ng/ml以上，表明孕体可保护黄体免受溶黄体作用。
第12天至第14天的非妊娠母羊早期黄体溶解过程与683个基因的差异表达相关，其中包括SERPINE1与THBS1。孕体在第12天至第14天的存在还诱导了743个基因的表达，包括干扰素刺激基因ISG15、MX1，以及PTX3、IL-6，并稳定了VEGF与LHR基因的表达。
综上，妊娠可规避溶黄体通路，并激活或稳定黄体中与干扰素、趋化因子、细胞黏附、细胞骨架、血管生成及上皮-间质转化相关的基因。本芯片分析共纳入12个无重复样本；我们将RT-PCR验证的样本量扩大至50个。本数据集仅包含Affymetrix芯片数据，不包含RT-PCR相关数据。