Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin, United States of America.
Department of Obstetrics and Gynecology, University of California, Irvine, California, United States of America.
PLoS One. 2022 Apr 29;17(4):e0267826. doi: 10.1371/journal.pone.0267826. eCollection 2022.
Angiogenesis is vital during pregnancy for remodeling and enhancing vasodilation of maternal uterine arteries, and increasing uterine blood flow. Abnormal angiogenesis is associated with decreased uteroplacental blood flow and development of pregnancy disorders such as gestational hypertension, preeclampsia, fetal growth restriction, preterm delivery, stillbirth, and miscarriage. The mechanisms that contribute to normal angiogenesis remain obscure. Our previous studies demonstrated that expression of the angiotensin type 2 receptor (AT2R) is increased while the angiotensin type 1 receptor (AT1R) is unchanged in the endothelium of uterine arteries, and that AT2R-mediated pregnancy adaptation facilitates enhanced vasodilation and uterine arterial blood flow. However, the role of AT2R in regulating angiogenesis during pregnancy has never been studied. This study examines whether or not AT2R activation induces angiogenesis and, if so, what mechanisms are involved. To this end, we used primary human uterine artery endothelial cells (hUAECs) isolated from pregnant and nonpregnant women undergoing hysterectomy. The present study shows that Compound 21, a selective AT2R agonist, induced proliferation of pregnant-hUAECs, but not nonpregnant-hUAECs, in a concentration-dependent manner, and that this C21-induced mitogenic effect was blocked by PD123319, a selective AT2R antagonist. The mitogenic effects induced by C21 were inhibited by blocking JNK-but not ERK, PI3K, and p38-signaling pathways. In addition, C21 concentration dependently increased cell migration and capillary-like tube formation in pregnant-hUAECs. The membrane-based antibody array showed that C21 increased expression of multiple angiogenic proteins, including EGF, bFGF, leptin, PLGF, IGF-1, and angiopoietins. Our qPCR analysis demonstrates that C21-induced increase in expression of these angiogenic proteins correlates with a proportional increase in mRNA expression, indicating that AT2R activates angiogenic proteins at the transcriptional level. In summary, the present study shows that AT2R activation induces angiogenesis of hUAECs in a pregnancy-specific manner through JNK-mediated pathways with associated transcriptional upregulation of multiple proangiogenic proteins.
血管生成对于妊娠期间重塑和增强母体子宫动脉的血管舒张以及增加子宫血流量至关重要。异常的血管生成与胎盘血流减少以及妊娠并发症的发展有关，如妊娠期高血压、子痫前期、胎儿生长受限、早产、死产和流产。导致正常血管生成的机制仍不清楚。我们之前的研究表明，在子宫动脉的内皮细胞中，血管紧张素 II 型受体 (AT2R) 的表达增加，而血管紧张素 I 型受体 (AT1R) 不变，并且 AT2R 介导的妊娠适应促进了增强的血管舒张和子宫动脉血流。然而，AT2R 在妊娠期间调节血管生成的作用从未被研究过。本研究检查了 AT2R 激活是否诱导血管生成，如果是，涉及哪些机制。为此，我们使用了从接受子宫切除术的妊娠和非妊娠妇女中分离的原代人子宫动脉内皮细胞 (hUAEC)。本研究表明，选择性 AT2R 激动剂 Compound 21 以浓度依赖性方式诱导妊娠-hUAEC 的增殖，但不诱导非妊娠-hUAEC 的增殖，并且这种 C21 诱导的有丝分裂效应被选择性 AT2R 拮抗剂 PD123319 阻断。C21 诱导的有丝分裂效应被阻断 JNK 但不阻断 ERK、PI3K 和 p38 信号通路而被抑制。此外，C21 浓度依赖性地增加了妊娠-hUAEC 的细胞迁移和毛细血管样管形成。膜基抗体阵列显示，C21 增加了多种血管生成蛋白的表达，包括 EGF、bFGF、瘦素、PLGF、IGF-1 和血管生成素。我们的 qPCR 分析表明，C21 诱导的这些血管生成蛋白表达增加与 mRNA 表达的比例增加相关，表明 AT2R 通过 JNK 介导的途径在转录水平上激活血管生成蛋白。总之，本研究表明，AT2R 激活以妊娠特异性方式诱导 hUAEC 的血管生成，通过 JNK 介导的途径与多种促血管生成蛋白的转录上调相关。
