Regulation of immune cell recruitment and angiogenesis at the maternal-fetal interface in pigs

胚泡着床、胎盘形成和哺乳动物成功妊娠需要着床部位母胎两侧协调的血管发育/重塑和功能适应。在胚胎附着于母体子宫内膜时，血管丰富的子宫内膜对于胚胎成功附着和生长至关重要。植入后不久，这种脉管系统的生长对于促进营养物质和氧气运输到发育中的孕体至关重要。免疫细胞，特别是自然杀伤细胞、T细胞、树突状细胞和巨噬细胞被募集到猪的植入部位，在那里它们在血液脉管系统发育和母胎串扰的调节中具有关键作用。在NSERC-DG项目的支持下，我们已经确定了猪妊娠早期子宫内膜淋巴细胞从细胞毒性到血管生成（促进血管生长）的范式转变功能。然而，这些免疫细胞如何被招募到动态的母胎界面或其妊娠特异性功能的基本问题仍然没有答案。我们假设子宫内膜免疫细胞通过特异性趋化因子信号被募集并定位在猪母胎界面内。此外，母体免疫细胞和胎儿滋养层细胞的功能由microRNA调节。利用我们在猪生殖免疫学方面的成熟和有据可查的专业知识，本提案的目标1解决了免疫细胞是否从子宫内膜祖细胞局部分化或在妊娠早期从血液中招募到母胎界面并确定其功能。 该提案的目的2集中于确定miRNA是否调节子宫内膜免疫细胞发育及其与胎儿滋养层细胞的通讯。在第三个目标中，我们将评估外泌体在母体免疫细胞和胎儿滋养层细胞之间穿梭microRNA中的作用。这些基础研究将是系统评价猪子宫内膜中的免疫细胞祖细胞及其分化形成新血管发育所需的其他免疫细胞和孕体生长过程中的其他几个关键过程的第一步。这项研究还将为microRNA介导的母体和胎儿细胞之间的通讯提供关键见解。在未来，我们将继续围绕动态和不断变化的母胎界面的免疫调节机制进行研究。从该计划中获得的知识将有助于利用生殖过程来改善胎儿存活率/畜群生产力，不仅适用于猪/猪肉行业，还适用于其他具有类似非侵入性胎盘的家畜，如牛和马。拟议的研究将为2名博士生和8名本科生提供培训。

Blastocyst implantation, placentation and successful mammalian pregnancy require coordinated blood vessel development/ remodeling and functional adaptations on both maternal-fetal sides of implantation sites. At the time of embryo attachment to the maternal uterine lining, a richly vascularized endometrium is critical for successful embryo attachment and growth. Shortly after implantation, growth of this vasculature is essential to facilitate nutrients and oxygen transport to the developing conceptus. Immune cells, in particular natural killer cells, T cells, dendritic cells and macrophages are recruited to the implantation sites in pigs where they have pivotal roles in blood vasculature development and regulation of maternal-fetal cross talk. With support from NSERC-DG program, we have identified paradigm shift functions of endometrial lymphocytes from being cytotoxic to angiogenic (blood vessel growth promoting) during early pig pregnancy. However, fundamental question of how these immune cells recruited to the dynamic maternal-fetal interface or on their pregnancy specific functions are remain unanswered. We hypothesize that endometrial immune cells are recruited and positioned within the porcine maternal-fetal interface by specific chemokine signals. Further, the functions of maternal immune cells and fetal trophoblasts are regulated by microRNAs. Using our established and documented expertise in porcine reproductive immunology, Aim 1 of this proposal addresses whether immune cells differentiate locally from endometrial progenitors or recruited from blood to the maternal-fetal interface during early pregnancy and identify their functions. Aim 2 of this proposal is focused on determining whether miRNA regulate endometrial immune cell development and their communication with fetal trophoblasts. In the third Aim, we will evaluate role of exosomes in shuttling microRNAs between maternal immune cells and fetal trophoblasts. These foundational studies will be the first step in systematic evaluation of immune cell progenitors residing in the pig endometrium and their differentiation to form other immune cells required for new blood vessel development and several other key processes during the conceptus growth. This research will also provide key insights into microRNA mediated communication between maternal and fetal cells. In the future, we will continue investigation around immunoregulatory mechanisms at the dynamic and ever changing maternal-fetal interface. Knowledge gained from this program will help exploit reproductive processes for improvement in fetal survival/herd productivity not only for pig/pork industry but also for other domestic animals with similar non-invasive placentation such as cattle and horse. Proposed research will provide training for 2 PhD and 8 undergraduate students.