Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
Human Sperm Bank, National Research Institute for Family Planning, Beijing, China.
Reprod Sci. 2024 Sep;31(9):2718-2730. doi: 10.1007/s43032-024-01526-7. Epub 2024 Apr 18.
In women of childbearing age, extensive decidualization, shedding and remodeling of the endometrium during the menstrual cycle are fundamental for successful pregnancy. The role of prostaglandins (PGs) in menstruation has long been proposed in humans, and the rate-limiting enzyme cyclooxygenase was shown to play a key role in endometrial breakdown and shedding in a mouse menstrual-like model in our previous study. However, the specific types of PGs involved and their respective roles remain unclear. Therefore, our objective was to investigate the mechanism through which PGs regulate endometrial disintegration. In this study, the microscopy was observed by HE; the protein levels of prostaglandins E1 (PGE1), prostaglandins E2 (PGE2), prostaglandin F2α (PGF2α) and Prostaglandin I2 (PGI2) were detected by ELISA; the mRNA level of Pfgfr2, Vascular Endothelial Growth Factor(Vegf), Angiostatin and Hypoxia inducible factor-1α (Hif1α) were examined by real-time PCR; PTGFR Receptor (PTGFR), VEGF, Angiostatin and HIF-1α protein levels were investigated by western blotting; the locations of protein were observed by Immunohistochemistry; HIF-1α binding PTGFR promoter was detected by Chromatin Immunoprecipitation (ChIP) and real-time PCR. We found that the concentrations of PGE1, PGE2, and PGF2α all increased significantly during this process. Furthermore, Ptgfr mRNA increased soon after Progesterone (P4) withdrawal, and PTGFR protein levels increased significantly during abundant endometrial breakdown and shedding processes. PTGFR inhibitors AL8810 significantly suppressed endometrial breakdown and shedding, promoted Angiostatin expression, and reduced VEGF-A expressions and vascular permeability. And HIF-1α and PTGFR were mainly located in the luminal/gland epithelium, vascular endothelium, and pre-decidual zone. Interestingly, HIF-1α directly bound to Ptgfr promoter. Moreover, a HIF-1α inhibitor 2-methoxyestradiol (2ME) significantly reduced PTGFR expression and suppressed endometrial breakdown which was in accord with PTGFR inhibitor's effect. Similar changes occurred in human stromal cells relevant to menstruation in vitro. Our study provides evidence that PGF2α/PTGFR plays a vital role in endometrial breakdown via vascular changes that are regulated by HIF-1α during menstruation.
在育龄妇女中，广泛的蜕膜化、子宫内膜在月经周期中的脱落和重塑对于成功妊娠至关重要。前列腺素（PGs）在人类月经中的作用早已被提出，我们之前的研究表明，限速酶环氧化酶在我们的小鼠月经样模型中子宫内膜崩解和脱落中发挥关键作用。然而，涉及的特定 PG 类型及其各自的作用仍不清楚。因此，我们的目标是研究 PG 调节子宫内膜崩解的机制。在这项研究中，通过 HE 观察显微镜；通过 ELISA 检测前列腺素 E1（PGE1）、前列腺素 E2（PGE2）、前列腺素 F2α（PGF2α）和前列环素 I2（PGI2）的蛋白水平；通过实时 PCR 检测 Pfgfr2、血管内皮生长因子（Vegf）、血管生成抑制素和缺氧诱导因子-1α（Hif1α）的 mRNA 水平；通过 Western blot 检测 PTGFR 受体（PTGFR）、VEGF、血管生成抑制素和 HIF-1α 蛋白水平；通过免疫组织化学观察蛋白质位置；通过染色质免疫沉淀（ChIP）和实时 PCR 检测 HIF-1α 结合 PTGFR 启动子。我们发现在此过程中 PGE1、PGE2 和 PGF2α 的浓度均显著增加。此外，孕酮（P4）撤去后不久 Ptgfr mRNA 增加，大量子宫内膜崩解和脱落过程中 PTGFR 蛋白水平显著增加。PTGFR 抑制剂 AL8810 显著抑制子宫内膜崩解和脱落，促进血管生成抑制素表达，降低 VEGF-A 表达和血管通透性。HIF-1α 和 PTGFR 主要位于腔上皮/腺上皮、血管内皮和前蜕膜区。有趣的是，HIF-1α 直接与 Ptgfr 启动子结合。此外，HIF-1α 抑制剂 2-甲氧基雌二醇（2ME）显著降低了 PTGFR 的表达，并抑制了子宫内膜的崩解，这与 PTGFR 抑制剂的作用一致。在体外与月经相关的人类基质细胞中也发生了类似的变化。我们的研究提供了证据，表明 PGF2α/PTGFR 通过血管变化在月经期间通过 HIF-1α 调节发挥重要作用，导致子宫内膜崩解。
