Myometrial PRs/ERs:targets for the prevention of preterm labor

描述(申请人提供)：早产发生在8-12%的怀孕，并导致70%-80%的新生儿死亡和发病率。由于我们无法阻止早产，这一重大公共卫生问题变得更加严重。解决这一问题的进展缓慢，主要是因为我们不完全了解如何控制人类怀孕子宫的收缩能力。我们的研究旨在通过询问分娩的关键荷尔蒙调节剂-类固醇荷尔蒙黄体酮和雌激素-如何影响子宫肌层收缩来填补这一知识空白。到目前为止，在所有研究的哺乳动物中，孕酮通过抑制子宫肌层的收缩来防止分娩，而雌激素通过将子宫肌层转变为高度收缩状态来促进分娩。与这些作用一致的是，分娩是由黄体酮的退出和子宫肌层雌激素影响的同时增加而开始的。在人类分娩中，这些事件是通过子宫肌层孕酮反应性降低(即功能性孕酮退出)和子宫肌层雌激素反应性增加(即功能性雌激素激活)发生的，各自部分地分别由肌层孕酮和雌激素受体(PR和ER)表达的特定变化介导。基于这一范例，我们认为，可以通过增加子宫肌层孕酮反应和/或抑制子宫肌层雌激素作用的治疗来预防早产。因此，对于特定的目标1，我们将确定PR表达的调节剂和雌激素反应性是否改变人妊娠子宫肌层细胞的孕酮反应性和子宫肌层收缩能力。为了促进对人类分娩控制的理解，我们需要改进现有的人类妊娠肌层的实验模型，并开发新的方法来研究其收缩是如何控制的。到目前为止，最好的人类妊娠子宫肌层体外模型是PHM1-31永生化的子宫肌层细胞系，它是从一个足月(非临产)子宫肌层发展而来的。这些细胞具有稳定的平滑肌细胞表型，并与它们来自妊娠子宫的来源一致，表达许多人类妊娠子宫肌层典型的收缩相关基因。因此，对于特定的目的2，我们将使用逆转录病毒转导来改进PHM1-31模型。为此，我们将培育稳定的转基因PHM1-31亚系，表达功能性转基因。这些子系将被用来研究子宫肌层孕酮和雌激素反应的过程和控制。专门设计和遗传稳定的PHM1-31亚系的开发将成为旨在阐明人类出生的激素控制研究的重要实验工具，以便我们能够开发预防早产的治疗策略。

DESCRIPTION (provided by applicant): Premature birth occurs in 8-12% of pregnancies and causes 70-80% of neonatal mortality and morbidity. This major public health problem is exacerbated by our inability to stop preterm labor. Progress in addressing this issue has been slow mainly because we do not fully understand how the contractility of the human pregnancy uterus is controlled. Our research aims to fill this knowledge-gap by asking how the key hormonal regulators of labor, the steroid hormones progesterone and estrogen, affect myometrial contractility. In all mammals studied to date, progesterone prevents labor by suppressing myometrial contractility, whereas estrogens promote labor by transforming the myometrium to a highly contractile state. Consistent with these actions, labor is initiated by the withdrawal of progesterone and the concurrent increase in estrogenic influences on the myometrium. In human parturition, these events occur by decreased myometrial progesterone responsiveness (i.e., functional progesterone withdrawal) and increased myometrial estrogen responsiveness (i.e., functional estrogen activation) each mediated, in part, by specific changes, respectively, in myometrial progesterone and estrogen receptor (PR and ER) expression. Based on this paradigm, we propose that preterm labor could be prevented by treatments that increase myometrial progesterone responsiveness and/or inhibit estrogenic actions on the myometrium. Therefore, for Specific Aim 1 we will determine whether modulators of PR expression and estrogen responsiveness alter progesterone responsiveness and myometrial contractile capacity in human pregnancy myometrial cells. To facilitate progress in understanding the control of human parturition we need to improve existing experimental models of the human pregnancy myometrium and develop novel approaches to study how its contractility is controlled. To date the best in vitro model for the human pregnancy myometrium is the PHM1- 31 immortalized myometrial cell line, developed from a term (not in labor) myometrium. These cells have a stable smooth muscle cell phenotype and consistent with their origin from the pregnancy uterus, express many of the contraction associated genes typical of the human pregnancy myometrium. Therefore, for Specific Aim 2 we will use retroviral transduction to improve the PHM1-31 model. To this end we will produce stable genetically modified PHM1-31 sub-lines expressing functional transgenes. These sub-lines will be used to examine the process and control of myometrial progesterone and estrogen responsiveness. The development of specifically engineered and genetically stable PHM1-31 sub-lines will be an important experimental tool for research aimed at elucidating hormonal control of human birth so that we can develop therapeutic strategies to prevent preterm birth.