HOXA10通过上调E-cadherin改善子宫内膜容受性的作用及机制研究

Endometrial receptivity is essential for embryo implantation and poor endometrial receptivity usually leads to infertility and early pregnancy loss. The molecular mechanisms that regulate endometrial receptivity remain unclear. Previous studies suggested that HOXA10 was not only a critical biomarker of endometrial receptivity but also an essential transcriptional regulation factor which regulated several molecules that related to endometrial receptivity establishment. We now found that expression of HOXA10 positively correlates with E-cadherin during the implantation window of endometrium. In vitro cell culture study suggested that the overexpression of HOXA10 could up-regulate E-cadherin expression. In addition, several HOXA10 potential binding sites are present in the promoter region of E-cadherin predicted by bioinformatics analysis. However, the precious mechanisms of HOXA10 in regulation of E-cadherin are unknown. In this project, we would like to detect the expression of HOXA10 and E-cadherin in more clinical samples and establish the relationship of these two factors during early pregnancy. Then, the underlying molecular mechanisms of how HOXA10 regulates E-cadherin expression will be investigated by using cell culture and mouse model. In addition, the RNA sequencing (RNA-Seq) will be used to explore the potential HOXA10-regulated targets and signaling pathways during endometrial receptivity establishment. The current study will broaden our vision in the mechanisms of the regulatory effects of HOXA10 on endometrial receptivity and may also provide experimental basis for future clinical intervention.

子宫内膜容受性良好是胚胎着床的关键，内膜容受性低下常导致不孕和妊娠丢失。目前我们对内膜容受性调控的分子机制仍知之甚少。早期研究认为HOXA10既是内膜容受性重要标志，也是调控其他内膜容受性相关分子的重要转录因子。本团队前期研究发现“种植窗”内膜HOXA10和E-cadherin表达正相关，体外细胞实验表明过表达HOXA10可上调E-cadherin水平，生物信息学预测E-cadherin启动子区存在HOXA10结合位点，然而HOXA10如何具体调控E-cadherin仍未清楚。本课题首先通过临床标本检测阐明两者在人类妊娠建立及维持过程中的相对表达关系；接着通过细胞模型和小鼠模型研究HOXA10调控E-cadherin的具体机制；最后RNA-seq测序分析，挖掘HOXA10调控内膜容受性新的靶基因和信号通路。本研究将拓宽我们对HOXA10调控内膜容受性机制的认识，为临床应用提供实验基础。

改善子宫内膜容受性是提高试管婴儿临床妊娠率、降低胚胎反复种植失败的关键。前人有研究报道HOXA10 能间接调控 E-cadherin，在细胞粘附作用中发挥作用，但具体分子机制尚未清楚，故进行了本研究。本课题研究主要包含以下内容：（1）探讨 HOXA10 和 E-cadherin 在人类妊娠建立及维持中的相互关系；（2）通过体外共培养模型研究 HOXA10 通过 E-cadherin 改善内膜容受性作用；（3）双荧光素酶报告实验和ChIP-QPCR实验探讨 HOXA10对E-cadherin 调控的具体分子机制；（4）小鼠模型中验证 HOXA10 对胚胎粘附的促进作用。研究结果发现：（1）相较于自然流产组，人工流产组中HOXA10和E-cadherin表达是上调的，且呈正相关。在子宫内膜上皮细胞中敲低和过表达HOXA10后，E-cadherin的mRNA和蛋白表达都是相应地上调和下调，证实两基因间可能存在某种调控关系。（2）通过体外共培养模型，发现HOXA10 和E-cadherin能促进滋养细胞球的粘附。（3）双荧光素酶报告实验和ChIP实验发现 HOXA10能靶向结合在E-cadherin启动子区。（4）CD1小鼠模型中进一步验证 HOXA10 对胚胎粘附的促进作用。这些结果提示：HOXA10能靶向结合在E-cadherin启动子区的片段来直接调控其表达，进而发挥HOXA10在子宫内膜容受性的作用，促进胚胎的粘附和着床；这丰富了HOXA10在内膜容受性中的调控网络，为临床干预治疗提供实验基础和分子靶标。