Vasopressin and Preeclampsia: Early Mechanisms for Prevention

先兆子痫（PreE）是妊娠期常见的高血压疾病， 产科死亡率每年有76，000名孕产妇和500，000名新生儿死亡。由于不清楚早期 PreE的妊娠病因，PreE的预防仅限于每日婴儿阿司匹林， 预防PreE。G蛋白信号调节因子（RGS）-2基因的多态性与 会增加先兆子痫的风险RGS 2是RGS蛋白质的B/R4家族的成员，其充当 一种内源性抑制剂的G-钙第二信使信号，一种常见的致病途径， 许多PreE相关激素如精氨酸加压素（AVP）。倍他米松（BTMZ）是常用药物 为有早产风险的妇女提供服务，以预防新生儿发病。我们的初步数据和文献 表明类固醇如BMTZ可以诱导RGS 2，从而关闭过多的致病性G-钙 在PreE中看到的信号。总之，这些数据使我们得出一个总体假设，即BMTZ通过以下方式阻止PreE： 恢复胎盘RGS 2信号传导并减少过度的G-钙信号传导， 与PreE相关的胎盘功能障碍有关。本建议的总体目标是： 评估过度的G β q信号传导对胎盘滋养层功能和先兆子痫的影响 表型，和（ii）证明BMTZ增加RGS 2活性，导致降低G β q-钙 从而防止PreE。目的1：探讨胎盘Gαq信号在胎盘细胞凋亡中的作用。 胎盘特异性hm 3Dq（Gα q激活）DREDD受体小鼠模型中的功能障碍和PreE。 与此一致，我们将测试减少的RGS 2通过过量的Gαq信号传导在PreE中的作用。 胎儿-胎盘RGS 2减少小鼠模型（WT母体X RGS 2-KO雄性）。在分离的总滋养层细胞中， 在这些小鼠模型和原发性人类先兆子痫胎盘组织中，我们将研究是否增加钙 释放导致与PreE一致的不良滋养层迁移。目标2将检验我们的假设， 在PreE中观察到的RGS 2减少是由于滋养层cAMP-CREB信号传导减少，如将在 （AVP）诱导的HTR-8/svNeo细胞和来自PreE妊娠的原代人滋养层细胞。我们将研究是否 cAMP-CREB-RGS 2信号传导的这种减少将通过在i）AVP诱导的 HTR-8/svNeo细胞，ii）临床上暴露于BMTZ的原代人滋养层细胞，和iii）在我们的慢性输注中， 血管加压素（CIV）小鼠PreE模型。这些研究将极大地阐明 RGS 2在先兆子痫发病机制中的作用，控制RGS 2表达的生理机制， 胎盘滋养层细胞和BMTZ在预防先兆子痫中的可能新用途。

Preeclampsia (PreE) is a prevalent hypertensive disorder in pregnancy and is a leading cause of worldwide obstetric mortality with 76,000 maternal and 500,000 neonatal deaths yearly. Due to the unclear early pregnancy etiology of PreE, prevention of PreE is limited to daily baby aspirin which may only modestly prevent PreE. A polymorphism in the gene encoding Regulator of G-Protein Signaling (RGS)-2 is associated with an increased risk for preeclampsia. RGS2 is a member of the B/R4 family of RGS proteins which acts as an endogenous inhibitor of Gq-calcium second-messenger signaling, a common pathogenic pathway for many PreE related hormones such as arginine vasopressin (AVP). Betamethasone (BTMZ) is commonly given to women at risk of preterm delivery to prevent neonatal morbidities. Our preliminary data and the literature suggest that steroids like BMTZ can induce RGS2, thereby turning off the excessive pathogenic Gq-calcium signaling seen in PreE. Together these data lead us to the overall hypothesis that BMTZ prevents PreE by restoring placental RGS2 signaling and decreasing the excessive Gq-calcium signaling that has been associated with PreE related placental dysfunction. The overall objectives of the current proposal are (i) to evaluate the impact excessive Gq signaling upon placental trophoblast function and preeclampsia phenotypes, and (ii) demonstrate that BMTZ increases RGS2 activity leading to decreased Gq-calcium signaling thereby preventing PreE. Aim 1 will examine the role of excess placental Gαq signaling on placental dysfunction and PreE in a placental specific hm3Dq (Gαq-activating) DREDD receptor mouse model. Consistent with this, we will test that reduced RGS2 results in PreE through the excessive Gαq signaling in a feto-placental RGS2 reduction mouse model (WT dams X RGS2-KO males). In isolated total trophoblasts from these mouse models and in primary human preeclamptic placental tissues, we will study if increased calcium release leads to the poor trophoblast migration consistent with PreE. Aim 2 will test our hypothesis that the observed reduction in RGS2 in PreE is due to reduced trophoblast cAMP-CREB signaling as will be tested in (AVP)-induced HTR-8/svNeo cells and primary human trophoblasts from PreE pregnancies. We will examine if this reduction in cAMP-CREB-RGS2 signaling will be reversed by treatment with BMTZ in i) AVP-induced HTR-8/svNeo cells, ii) primary human trophoblasts clinically exposed to BMTZ and iii) in our chronic infusion of vasopressin (CIV) mouse model of PreE. Together these studies will greatly clarify a potential causal role of RGS2 in the pathogenesis of preeclampsia, physiological mechanisms controlling RGS2 expression in placental trophoblasts and the possible novel use of BMTZ in the prevention of preeclampsia.