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

描述（由申请人提供）：早产发生在怀孕的8-12%，导致70-80%的新生儿死亡率和发病率。由于我们无法阻止早产，这一重大的公共卫生问题更加严重。解决这一问题的进展一直很缓慢，主要是因为我们不完全了解人类妊娠子宫的收缩是如何控制的。我们的研究旨在通过探究分娩的关键激素调节因子，类固醇激素黄体酮和雌激素如何影响子宫肌收缩性来填补这一知识空白。在迄今为止研究的所有哺乳动物中，黄体酮通过抑制子宫肌层收缩性来阻止分娩，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，分娩是由黄体酮的停药和同时增加的雌激素对子宫肌层的影响引起的。在人类分娩过程中，这些事件的发生是由于子宫肌层孕酮反应性降低（即，功能性孕酮戒断）和子宫肌层雌激素反应性增加（即，功能性雌激素激活），这两种反应分别部分地由子宫肌层孕酮和雌激素受体（PR和ER）表达的特异性变化介导。基于这种模式，我们建议通过增加子宫肌层孕酮反应性和/或抑制子宫肌层雌激素作用的治疗来预防早产。因此，在Specific Aim 1中，我们将确定PR表达和雌激素反应性的调节剂是否会改变人妊娠子宫肌瘤细胞的孕酮反应性和子宫肌瘤收缩能力。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子宫肌层实验模型，并开发新的方法来研究其收缩性是如何被控制的。迄今为止，人类妊娠子宫肌最好的体外模型是PHM1- 31永生化子宫肌细胞系，它是从妊娠期（非分娩期）子宫肌发育而来的。这些细胞具有稳定的平滑肌细胞表型，与它们来自妊娠子宫的起源一致，表达许多人类妊娠肌层典型的收缩相关基因。因此，对于Specific Aim 2，我们将使用逆转录病毒转导来改善PHM1-31模型。为此，我们将产生稳定的表达功能性转基因的转基因PHM1-31亚系。这些子线将用于检查子宫内膜黄体酮和雌激素反应的过程和控制。特异性工程和基因稳定的PHM1-31亚系的发展将是一个重要的实验工具，旨在阐明人类生育的激素控制，从而我们可以制定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.