Department of Obstetrics and Gynecology, Life Science Center, University Hospital and Medical Faculty of the Heinrich-Heine University Duesseldorf, Duesseldorf, Germany.
Department of OB/GYN & REI, UniKiD, University Hospital and Faculty of Medicine, Heinrich Heine University, Duesseldorf, Germany.
Reprod Biol Endocrinol. 2024 Feb 3;22(1):20. doi: 10.1186/s12958-024-01188-9.
Decidualization of endometrial cells is the prerequisite for embryo implantation and subsequent placenta formation and is induced by rising progesterone levels following ovulation. One of the hormone receptors contributing to endometrial homeostasis is Progesterone Receptor Membrane Component 1 (PGRMC1), a non-classical membrane-bound progesterone receptor with yet unclear function. In this study, we aimed to investigate how PGRMC1 contributes to human decidualization.
We first analyzed PGRMC1 expression profile during a regular menstrual cycle in RNA-sequencing datasets. To further explore the function of PGRMC1 in human decidualization, we implemented an inducible decidualization system, which is achieved by culturing two human endometrial stromal cell lines in decidualization-inducing medium containing medroxyprogesterone acetate and 8-Br-cAMP. In our system, we measured PGRMC1 expression during hormone induction as well as decidualization status upon PGRMC1 knockdown at different time points. We further conferred proximity ligation assay to identify PGRMC1 interaction partners.
In a regular menstrual cycle, PGRMC1 mRNA expression is gradually decreased from the proliferative phase to the secretory phase. In in vitro experiments, we observed that PGRMC1 expression follows a rise-to-decline pattern, in which its expression level initially increased during the first 6 days after induction (PGRMC1 increasing phase) and decreased in the following days (PGRMC1 decreasing phase). Knockdown of PGRMC1 expression before the induction led to a failed decidualization, while its knockdown after induction did not inhibit decidualization, suggesting that the progestin-induced 'PGRMC1 increasing phase' is essential for normal decidualization. Furthermore, we found that the interactions of prohibitin 1 and prohibitin 2 with PGRMC1 were induced upon progestin treatment. Knocking down each of the prohibitins slowed down the decidualization process compared to the control, suggesting that PGRMC1 cooperates with prohibitins to regulate decidualization.
According to our findings, PGRMC1 expression followed a progestin-induced rise-to-decline expression pattern during human endometrial decidualization process; and the correct execution of this expression program was crucial for successful decidualization. Thereby, the results of our in vitro model explained how PGRMC1 dysregulation during decidualization may present a new perspective on infertility-related diseases.
子宫内膜细胞的蜕膜化是胚胎着床和随后胎盘形成的前提，是由排卵后孕酮水平升高诱导的。对子宫内膜稳态有贡献的激素受体之一是孕激素受体膜成分 1（PGRMC1），一种非经典的膜结合孕激素受体，其功能尚不清楚。在这项研究中，我们旨在研究 PGRMC1 如何促进人蜕膜化。
我们首先在 RNA 测序数据集中分析了正常月经周期中 PGRMC1 的表达谱。为了进一步探索 PGRMC1 在人蜕膜化中的功能，我们采用诱导蜕膜化系统，该系统通过在含有甲羟孕酮和 8-Br-cAMP 的蜕膜化诱导培养基中培养两种人子宫内膜基质细胞系来实现。在我们的系统中，我们在激素诱导过程中测量 PGRMC1 的表达，并在不同时间点敲低 PGRMC1 后测量蜕膜化状态。我们进一步进行了邻近连接分析，以鉴定 PGRMC1 的相互作用伙伴。
在正常月经周期中，PGRMC1mRNA 的表达从增生期逐渐下降到分泌期。在体外实验中，我们观察到 PGRMC1 的表达呈上升-下降模式，其表达水平在诱导后第 6 天开始升高（PGRMC1 升高期），随后下降（PGRMC1 下降期）。在诱导前敲低 PGRMC1 的表达导致蜕膜化失败，而在诱导后敲低 PGRMC1 并不抑制蜕膜化，这表明孕激素诱导的“PGRMC1 升高期”对于正常蜕膜化是必要的。此外，我们发现孕酮处理后与 PGRMC1 相互作用的抑制素 1 和抑制素 2 的相互作用增加。与对照组相比，敲低每种抑制素都使蜕膜化过程变慢，这表明 PGRMC1 与抑制素协同调节蜕膜化。
根据我们的发现，PGRMC1 在人子宫内膜蜕膜化过程中的表达遵循孕激素诱导的上升-下降表达模式；正确执行这一表达程序对于成功的蜕膜化至关重要。因此，我们的体外模型结果解释了蜕膜化过程中 PGRMC1 的失调如何为与不孕相关的疾病提供新的视角。
