Molecular mechanism of LPA3-mediated uterine receptivity

描述（由申请人提供）：子宫容受性缺陷，包括子宫容受性延迟和子宫内膜非容受性，是导致不孕和早孕流产的关键母体因素。子宫如何转变为胚胎着床的接受状态的分子机制尚不清楚。众所周知，孕激素受体（PR）介导的激素信号对于所有哺乳动物子宫接受性的建立至关重要。PR在着床期子宫内具有动态的时空表达模式。子宫腔上皮和腺上皮PR的消失与子宫接受性的建立有关。在预期的“着床窗口”期间，子宫上皮PR下调失败与子宫接受性缺陷有关。LPA3 （LPAR3/EDG7）是溶血磷脂酸的第三个受体。子宫LPA3的下调与子宫内膜异位症患者子宫容受性缺陷有关，小鼠Lpar3的缺失导致子宫容受性延迟。在Lpar3（-/-）小鼠子宫未受感期4.5天（小鼠正常着床期4.0天），LE中可检测到持续的PR表达。在预期的“着床窗口”期间，LE中持续的PR表达是如何阻断子宫容受性的，以及PR介导的激素信号如何与局部靶点相互作用以控制子宫容受性仍是重要的知识空白。长期目标是了解子宫容受性的分子机制，从而帮助克服与子宫容受性缺陷相关的不孕症和早期妊娠丢失。本申请的总体目标是填补上述知识空白，特别是PR在LE中持续表达的意义以及PR与LPA3在LE中的相互作用。基于支持性初步数据制定的中心假设是PR与LPA3相互作用以协调调节子宫接受性。其基本原理是，了解PR在LE中的意义及其与LPA3的相互作用，将有助于进一步了解子宫接受性的分子机制。为了实现此应用程序的目标，将追求三个具体目标。目的1。基于LE中PR持续表达失调基因/分子通路导致子宫非接受性的工作假设，确定LE中PR持续表达失调的分子通路。目标2。基于LE中PR与LPA3相互调节以建立子宫接受性的工作假设，确定LE中PR与LPA3的相互作用。目标3。确定LPA3在着床前第3天调控分子通路中的作用。5子宫内膜，基于LPA3在LE中直接和/或通过PR调控其子宫靶基因影响子宫容受性的工作假设。激光显微解剖、基因谱分析、免疫印迹、ChIP测定和免疫沉淀是将采用的方法之一。这项工作意义重大，因为了解子宫容受性的分子机制对于发现和治疗与子宫容受性缺陷相关的不孕症和早期妊娠丢失的诊断和治疗方法至关重要。

DESCRIPTION (provided by applicant): Defective uterine receptivity, including delayed uterine receptivity and non-receptive endometrium, is the key maternal factor for infertility and early pregnancy loss. The molecular mechanism of how a uterus transforms into a receptive state for embryo implantation is not well understood. It is well recognized that progesterone receptor (PR)-mediated hormonal signaling is essential for the establishment of uterine receptivity in all mammals studied. PR has dynamic spatiotemporal expression patterns in the peri-implantation uterus. The disappearance of PR from uterine luminal (LE) and glandular epithelium is associated with the establishment of uterine receptivity. Failure of such down regulation of PR in uterine epithelium during the expected "implantation window" is associated with defective uterine receptivity. LPA3 (LPAR3/EDG7) is the third receptor for lysophosphatidic acid. Down regulation of uterine LPA3 is implicated in defective uterine receptivity in endometriosis patients and deletion of Lpar3 in mice leads to delayed uterine receptivity. Sustained PR expression in LE is detected in the non-receptive day 4.5 Lpar3(-/-) mouse uterus (normal implantation: ~day 4.0 in mouse). How the sustained PR expression in LE during the expected "implantation window" blocks uterine receptivity and how PR-mediated hormonal signaling interacts with local targets to control uterine receptivity remain as significant knowledge gaps. The long-term goal is to understand the molecular mechanism of uterine receptivity thus help overcome infertility and early pregnancy loss associated with defective uterine receptivity. The overall objective of this application is to fill the mentioned knowledge gaps, specifically the significance of sustained PR expression in LE and the interplay between PR and LPA3 in LE. The central hypothesis, formulated based on supportive preliminary data, is that PR interplays with LPA3 to coordinately regulate uterine receptivity. The rationale is that understanding the significance of PR in LE and its interplay with LPA3 will provide more insight into the molecular mechanism of uterine receptivity. To achieve the goal of this application, three specific aims will be pursed. Aim 1. Determine molecular pathways dysregulated in LE with sustained PR expression, based on the working hypothesis that sustained PR expression in LE dysregulates genes/molecular pathways leading to a non-receptive uterus. Aim 2. Determine interplay between PR and LPA3 in LE, based on the working hypo- thesis that PR and LPA3 mutually regulate each other in LE for the establishment of uterine receptivity. Aim 3. Determine role of LPA3 in regulating molecular pathways in preimplantation day 3. 5 endometrium, based on the working hypothesis that LPA3 regulates its uterine target genes to influence uterine receptivity directly and/or via PR in LE. Laser microdissection, gene profiling, immunoblotting, ChIP assay, and immonoprecipitation are among the approaches that will be employed. The proposed work is significant because understanding the molecular mechanism of uterine receptivity is critical for developing diagnostic and therapeutic approaches to detect and treat infertility and early pregnancy loss associated with defective uterine receptivity. PUBLIC HEALTH RELEVANCE: The proposed research is relevant to public health because defective uterine receptivity is a key factor for two important public health problems, infertility and early pregnancy loss. This proposal aims to decipher how a local factor LPA3 interplays with progesterone receptor in uterine luminal epithelium to control uterine receptivity. The understanding of the molecular mechanism in establishment of uterine receptivity will provide the foundation for drug discoveries to treat infertility and early pregnancy loss associated with defective uterine receptivity.