Innate Immune Responses of Trophoblasts in Pregnancy

描述(由申请人提供)：这些研究是我们实验室从先前资助的RO1开始的实验的继续。由于没有良好的生物标志物或预防策略，感染相关的妊娠并发症是一个重要的临床问题。Toll样受体(TLR)在母胎界面的表达和功能的调节可能决定妊娠的成败。只有了解了控制滋养细胞TLRs功能的机制，我们才能进入临床应用，以确定更好的方法来预测妊娠结局，并治疗有感染相关妊娠并发症风险的妇女。胎盘细胞过度凋亡与先兆子痫和早产有关；然而，最初的触发因素和涉及的机制尚不完全清楚。我们认为，感染是胎盘细胞凋亡的潜在触发因素，一些TLRs可以介导这一反应。具体地说，我们的中心假设是，某些细菌和病毒成分通过TLRs诱导滋养层细胞凋亡，导致不良妊娠结局，如早产或先兆子痫。在我们已发表的研究中，我们发现由革兰氏阳性细菌肽聚糖(PDG)激活的TLR2和由病毒单链RNA激活的TLR8通过两条不同的途径触发人早孕滋养层细胞的凋亡：TLR2直接介导细胞凋亡，这是由TLR2共受体TLR6差异调节的。相反，TLR8通过上调细胞产生的IFN2间接介导细胞凋亡。我们的目标是进一步确定TLR2和TLR8介导滋养层细胞凋亡的细胞和分子机制，以响应细菌和病毒成分，并确定它们对妊娠结局的影响。在这一总体目标中，我们将解决在我们的知识中存在重大差距的创新领域，例如：DNA甲基化对TLR表达的调节；TLRs对滋养层MIR的调节；TLR8在滋养层中的功能；以及病毒单链RNA对妊娠结局的影响。我们还将把我们的体外研究结果转化为一项研究，以开发更好的预测性和预防性策略。因此，我们的具体目标是：1.确定细菌成分对TLR2诱导的细胞凋亡的调节作用。2.确定TLR8在滋养层细胞对病毒成分的反应机制。3.确定microRNAs在TLR2和TLR8介导的滋养层细胞凋亡调节中的作用。4.评估TLRs在妊娠中的作用。虽然细菌感染和妊娠并发症之间的联系已经确立，但关于病毒感染如何影响怀孕的了解较少。尽管最近我们对胎盘TLRs在妊娠中的作用有了更多的了解，但我们对其中涉及的具体机制的了解仍然有限，TLRs在介导细胞凋亡中的作用也是如此。我们的发现将进一步加深我们对正常胎盘功能的理解，并将有助于更好地理解、预测和治疗感染相关妊娠并发症。 公共卫生相关性：这项建议的主要目标是了解细菌和病毒感染通过Toll样受体诱导胎盘细胞凋亡的机制。我们的研究将促进我们对感染相关妊娠并发症的发病机制的理解，例如早产。我们的发现也可能导致新的诊断标记物、治疗策略和新药物靶点的线索。

DESCRIPTION (provided by applicant): These studies are a continuation of experiments originated in our laboratory, from a previously funded RO1. Since there are no good biomarkers or preventative strategies, infection-associated pregnancy complications represent an important clinical problem. The regulation of Toll-like receptor (TLR) expression and function at the maternal-fetal interface may determine whether a pregnancy succeeds or fails. By understanding the mechanisms that control how trophoblast TLRs function, only then can we move to clinical applications to determine better ways to predict pregnancy outcome and treat women at risk of infection-associated pregnancy complications. Excessive placental apoptosis has been associated with preeclampsia and preterm labor; however the initial trigger and mechanisms involved are not fully understood. We propose that infections represent a potential trigger for placental apoptosis, and that some TLRs can mediate this response. Specifically, our central hypothesis is that some bacterial and viral components, through TLRs, induce trophoblast apoptosis, leading to adverse pregnancy outcome, such as preterm labor or preeclampsia. In our published studies we found TLR2 activation by gram-positive bacterial peptidoglycan (PDG), and TLR8 activation by viral ssRNA, trigger human first trimester trophoblast apoptosis via two distinct pathways: TLR2 directly mediates apoptosis, and this is differentially regulated by the TLR2 co-receptor, TLR6. In contrast, TLR8 indirectly mediates apoptosis by upregulating the cell's production of IFN2. Our objectives are to further characterize the cellular and molecular mechanisms by which TLR2 and TLR8 mediate trophoblast apoptosis in response to bacterial and viral components, and to determine their impact on pregnancy outcome. Within this overall goal, we will address innovative areas in which there are major gaps in our knowledge, such as the: regulation of TLR expression by DNA methylation; regulation of trophoblast miRs by TLRs; function of TLR8 in the trophoblast; and the effect of viral ssRNA on pregnancy outcome. We will also apply translate our in vitro findings into a study to develop better predictive and preventative strategies. Thus, our specific aims are to: 1. Determine the regulation of TLR2-induced apoptosis in response to bacterial components. 2. Determine the mechanism by which TLR8 functions in the trophoblast in response to viral components. 3. Determine the role of microRNAs in the regulation of TLR2- and TLR8-mediated trophoblast apoptosis. 4. Evaluate the role of TLRs in pregnancy. While the link between bacterial infections and pregnancy complications is well established, less is known about how viral infections affect pregnancy. Despite a recent increase in our understanding of the role of placental TLRs in pregnancy, our knowledge about the specific mechanisms involved is still limited, as is the role of TLRs in mediating apoptosis. Our findings will further our understanding of normal placental function, and will lead to a better understanding, prediction and treatment of infection-associated pregnancy complications. PUBLIC HEALTH RELEVANCE: The major objective of this proposal is to understand the mechanisms by which bacterial and viral infections, through the Toll-like receptors, induce placental apoptosis. Our studies will advance our understanding of the pathogenesis of infection-associated pregnancy complications, such as preterm labor. Our findings may also lead to new diagnostic markers, therapeutic strategies, and clues for novel drug targets.