Placenta and uterus transcriptomes from transgenic mice expressing human corticotropin-releasing hormone in placenta

Purpose: Parturition is delayed by approximately 12 hours in transgenic mice expressing human corticotropin-releasing hormone (CRH) in placenta. The goal of the study was to identify the pathways in reproductive tissues (uterus and placenta) altered by placental expression of human CRH. Methods: Human BAC RP11-366K18 (CHORI) containing human CRH and cis-regulatory region was inserted into the mouse genome by microinjection and random integration to create the BAC1 line. The CRISPR/Cas9 system was used to delete a CRH regulatory element from the BAC1 line to create the CR1 line, eliminating expression of CRH in placenta. Total expression of uterus and placenta by RNA-seq at embryonic day 18.5 were compared between BAC1, CR1, and nontransgenic mice. Results: Genes known to be associated with luteolysis and initiation of parturition (Cav1, Gja1, Oxtr, Ptgs1, Ptgs2) were not differentially expressed in uterus of this model. Conclusions: CRH-mediated delay of parturition is likely independent of luteolysis. mRNA-seq was performed on uterus and placenta harvested at embryonic day 18.5 from nontransgenic mice, Tg(BAC1) mice, and Tg(CR1) mice.

【研究目的】在胎盘中表达人类促肾上腺皮质激素释放激素（corticotropin-releasing hormone, CRH）的转基因小鼠中，分娩进程会延迟约12小时。本研究旨在鉴定胎盘表达人类CRH所改变的生殖组织（子宫与胎盘）中的信号通路。【实验方法】通过显微注射与随机整合的方式，将包含人类CRH及其顺式调控区域的人类细菌人工染色体（Bacterial Artificial Chromosome, BAC）RP11-366K18（CHORI）插入小鼠基因组，构建BAC1品系。利用CRISPR/Cas9系统从BAC1品系中敲除CRH调控元件，构建CR1品系，以此消除胎盘中CRH的表达。在胚胎第18.5天采集子宫与胎盘样本，通过RNA测序（RNA-seq）比较BAC1、CR1及非转基因小鼠的整体基因表达谱。【实验结果】已知与黄体溶解及分娩启动相关的基因（Cav1、Gja1、Oxtr、Ptgs1、Ptgs2）在该模型的子宫组织中未出现差异表达。【研究结论】CRH介导的分娩延迟可能独立于黄体溶解过程。本研究对非转基因小鼠、Tg(BAC1)小鼠及Tg(CR1)小鼠胚胎第18.5天采集的子宫和胎盘样本进行了mRNA测序（mRNA-seq）。