REGULATION OF RENIN AND PREECLAMPTIC HYPERTENSION

描述：（改编自研究者摘要）许多组织分泌一种无活性的肾素前体。43个氨基酸的前节段去除被认为是产生活性肾素，主要发生在肾脏。最近关于转基因子痫前期小鼠模型的数据支持生殖肾素在其发病机制中的作用，我们在人类子痫前期个体肾素表达增加的数据证实了这一作用。为了使肾素具有这样的功能作用，细胞对活性肾素的加工应该发生在局部。子宫肾素-血管紧张素系统的细胞和分子方面尚未得到充分的研究。在肾素基因启动子中存在雌激素和孕激素反应元件，提示性类固醇在调节催乳素表达中起作用。我们最近的数据表明，孕酮处理子宫内膜基质细胞（体外脱胎化）通过增加前肾素表达和以激素特异性方式增加前肾素向肾素的转化，从而增加活跃的肾素分泌，并且人妊娠期的蜕细胞将前肾素转化为肾素。我们最近在HEK293细胞中进行的共转染实验和蜕细胞中组织蛋白酶B的抑制表明，组织蛋白酶B可能具有促凝素转化酶的功能。我们推测，病理性的肾素水平升高可能直接引发子痫前期，而性类固醇可能诱导prorenin及其前转化酶（PC）的表达，从而调节成熟肾素的分泌。因此，我们的目标是：1)通过活性和N端测序，证明蜕质细胞在体外分泌有活性的成熟肾素；2)通过(i)使用pc和组织蛋白酶B探针的northern分析，（ii）定义组成型和调节型肾素分泌，以及（iii）检查组织蛋白酶B抑制对prorentin加工的影响，确定负责prorentin激活的蜕细胞内蛋白酶；(b)检测内源性蛋白酶表达的调控；3)通过(a)免疫显微镜下与促肾素在囊泡中共定位，(b)在标准细胞系中共转染促肾素和候选活化酶表达载体，验证其功能，并证明其加工成成熟的活性肾素。这些研究将提高我们对孕激素在生殖肾素调控中的作用的认识，并可能为研究子痫前期的病理生理提供新的方向。

DESCRIPTION: (Adapted from the Investigator's Abstract) Many tissues secrete an inactive pro-form of renin. A 43 amino acid pro- segment removal to produce active renin is believed to occur, primarily in the kidney. Recent data on transgenic mouse model of preeclampsia support a role of reproductive renin in its pathogenesis and our data on increased decidual renin expression in human preeclampsia confirms this role. For renin to have such a functional role, cellular processing to active renin should occur locally. The cellular and molecular aspects of the uterine renin- angiotensin system have not been adequately investigated. Presence of estrogen and progesterone response elements in the promoter of renin gene suggests a role for the sex steroids in the regulation of prorenin expression. Our recent data suggest that progesterone treatment of endometrial stromal cells (in vitro decidualization) increases active renin secretion by increasing prorenin expression and by increasing conversion of prorenin to renin in a hormone- specific manner, and that decidual cells from human gestation process prorenin to renin. Our most recent co-transfection experiment in HEK293 cells and cathepsin B inhibition in decidual cells suggest that cathepsin B may function as a prorenin convertase. We hypothesize that pathologic increase in decidual renin may proximately initiate preeclampsia, and sex steroids may induce expression of prorenin and its proconvertase (PC), thereby regulating mature renin secretion. Therefore, the objectives are: 1) To demonstrate that decidual stromal cells in vitro secrete active mature renin, as assayed by activity and by N terminal sequencing; 2) To identify the decidual cell endoprotease responsible for prorenin activation by (i) northern analysis with probes for PCs and cathepsin B, and (ii) defining constitutive versus regulated renin secretion, and (iii) examining the effect of cathepsin B inhibition on prorenin processing; (b) To examine regulation of endoprotease expression; 3) To confirm that the candidate-activating enzyme is the specific prorenin convertase by (a) immuno-microscopic co-localization with prorenin in the vesicles and (b) functional verification by co-transfection of prorenin and candidate-activating enzyme expression vectors in a standard cell line and demonstration of processing to mature active renin. These studies will improve our understanding of the role of progesterone in the regulation of reproductive renin and may provide a novel direction for investigating the pathophysiology of preeclampsia.