Uterine infection alters bovine endometrium, oviduct and granulosa transcriptome three months later. Uterine infection alters bovine endometrium, oviduct and granulosa transcriptome three months later

Here we tested the hypothesis that intrauterine infusion of pathogenic bacteria leads to changes in the transcriptome of the reproductive tract in dairy cattle three months later. We used virgin Holstein heifers to avoid the confounding effects of periparturient problems, metabolic stress and lactation. Animals were infused intrauterine with endometrial pathogenic bacteria Escherichia coli and Trueperella pyogenes to induce clinical endometritis (n = 4) and compared with control animals (n = 6). Three months after infusion, the caruncular and intercaruncular endometrium, isthmus and ampulla of the oviduct, and granulosa cells from dominant ovarian follicles were profiled by RNA-sequencing. Compared with control, bacterial infusion altered the transcriptome of all the tissues. Most differentially expressed genes were tissue-specific, with 109 differentially expressed genes unique to the caruncular endometrium, 57 in the intercaruncular endometrium, 65 in the isthmus, 298 in the ampulla, and 83 in granulosa cells. Surprisingly, despite infusing the bacteria into the uterus, the granulosa cells had more predicted upstream regulators of differentially expressed genes than all the other tissues combined. In conclusion, there was evidence of long-term changes to the transcriptome of the endometrium, oviduct and even the granulosa cells after intrauterine infusion of pathogenic bacteria, which implies that all these tissues contribute to the infertility that persists after endometritis. Overall design: The present study aimed to explore whether uterine infection with bacteria that cause endometritis leads to long-term changes in the reproductive tract. Specifically, we tested the hypothesis that intrauterine infusion of pathogenic bacteria leads to changes in the transcriptome of the reproductive tract in dairy cattle three months later. To test this hypothesis, we exploited a model of clinical endometritis in virgin Holstein heifers, which allowed us to avoid the confounding effects of periparturient problems, metabolic stress and lactation (Piersanti et al. 2019b). We infused animals intrauterine with control vehicle or with E. coli and T. pyogenes to induce endometritis, and collected endometrium, oviduct and granulosa cells three months later. We then compared the transcriptomes of each of these tissues between bacteria-infused and control animals using RNA-sequencing (RNAseq) and pathway analysis.

本研究旨在验证以下假说：向奶牛子宫内灌注致病菌后，其生殖道转录组会在三个月后发生改变。本研究选用处女荷斯坦青年母牛作为实验动物，以规避围产期问题、代谢应激与泌乳带来的混杂效应。向4头实验牛子宫内灌注子宫内膜源性致病菌大肠杆菌（Escherichia coli）与化脓隐秘杆菌（Trueperella pyogenes）以构建临床型子宫内膜炎模型，另设6头对照牛。于灌注后三个月，采集子宫阜子宫内膜、子宫阜间子宫内膜、输卵管峡部与壶腹部，以及优势卵巢卵泡来源的颗粒细胞，通过RNA测序（RNA-sequencing）进行转录组分析。与对照组相比，致病菌灌注可改变所有受试组织的转录组。绝大多数差异表达基因具有组织特异性：子宫阜子宫内膜特有109个差异表达基因，子宫阜间子宫内膜为57个，输卵管峡部65个，壶腹部298个，颗粒细胞83个。值得注意的是，尽管仅向子宫内灌注致病菌，颗粒细胞中预测得到的差异表达基因上游调控因子数量，竟多于其余所有组织的总和。综上，本研究证实，子宫内灌注致病菌后，子宫内膜、输卵管乃至颗粒细胞的转录组均出现长期改变，这表明上述所有组织均与子宫内膜炎后持续存在的不孕症相关。实验设计：本研究旨在探究引发子宫内膜炎的子宫致病菌感染是否会导致生殖道出现长期转录组改变。具体而言，本研究验证的假说是：向奶牛子宫内灌注致病菌后，其生殖道转录组会在三个月后发生改变。为验证该假说，本研究采用处女荷斯坦青年母牛的临床型子宫内膜炎模型，以规避围产期问题、代谢应激与泌乳带来的混杂效应（Piersanti等，2019b）。向实验牛子宫内灌注对照溶媒或大肠杆菌与化脓隐秘杆菌以构建子宫内膜炎模型，并于灌注后三个月采集子宫内膜、输卵管组织与颗粒细胞。随后通过RNA测序与通路分析，比较致病菌灌注组与对照组各组织的转录组差异。