A novel role for endothelial mineralocorticoid receptors in obesity-associated cardiovascular disease in females

项目总结 肥胖的绝经前女性比肥胖的男性患血管疾病的风险更高，这表明 肥胖否定了女性性激素的保护作用，然而，潜在的机制尚不清楚。 脂肪衍生激素瘦素调节肥胖男性和女性的高血压，然而， 机械路径是性别特有的。临床数据显示女性心血管治疗效果较好 使用盐皮质激素受体(MR)拮抗剂的患者比男性患者少。因此，我们的实验室发表了瘦素- 在女性中，诱发性高血压和内皮功能障碍是由醛固酮-MR轴介导的。在这 我们提供了一些新的初步数据：1.雌性小鼠对醛固酮更敏感- 内皮功能障碍2.内皮特异性MR(ECMR)缺失与上皮钠通道 (ENAC)拮抗剂预防瘦素引起的女性内皮损伤3.女性的内皮细胞 小鼠和人类比男性表达更多的eCMR 4.卵巢切除使eCMR的表达减弱，而eCMR的表达被恢复 ECMR的表达与孕酮水平相关6.蛋白质 抑制激酶C(PKC)阻止孕酮刺激的eCMR表达7.怀孕小鼠发育 显著的内皮功能障碍对瘦素8的反应。胎盘缺血导致瘦素和 妊娠大鼠体内的醛固酮水平。因此，我们假设内皮孕酮受体激活 上调eCMR表达，介导瘦素诱导的内皮功能障碍和高血压 绝经前和怀孕的雌性小鼠。三个具体目标将严格检验我们的假设：1(K99)： 孕酮通过内皮孕酮上调内皮糖皮质激素受体的表达 受体激活，2(K99)：内皮细胞盐皮质激素受体介导瘦素诱导的内皮细胞 雌性小鼠的功能障碍和高血压，3(R00非依赖)：瘦素诱导的，醛固酮介导的 盐皮质激素受体激活在肥胖患者血管内皮功能障碍和高血压中的作用 先兆子痫。我们将利用新的转基因小鼠模型(内皮特异孕酮缺乏 受体和ENaC)，内皮细胞培养技术研究孕酮介导的PKC机制 并与该领域的专家合作，确定eCMR在瘦素中的调节和功能相关性- 介导性内皮功能障碍与绝经前女性高血压。此外，在独立的 阶段，我们将利用降低子宫灌注压的小鼠胎盘模型来改变入路 一项突破性的研究瘦素在高血压妊娠中的作用。这些研究的结果 将进一步加深我们对女性内皮功能障碍和高血压的性别特异性机制的了解 并可能导致改善对肥胖孕妇和非孕妇的治疗策略。此外， 导师就此申请、奥古斯塔大学的环境和培训计划提供的资源 随函附上的申请者将朝着过渡到独立研究人员的目标前进。

PROJECT SUMMARY Obese premenopausal women are at higher risk for vascular disorders than obese men demonstrating that obesity negates protective effects of female sex hormones, however, the underlying mechanisms are unknown. The adipose-derived hormone leptin mediates hypertension in obese males and females, however, the mechanistic pathways are sex-specific. Clinical data report better cardiovascular treatment outcomes in females treated with mineralocorticoid receptor (MR) antagonists than males. In accordance, our lab published that leptin- induced hypertension and endothelial dysfunction is mediated by the aldosterone-MR axis in females. In this proposal we provide a number of novel preliminary data: 1. female mice are more sensitive to aldosterone- induced endothelial dysfunction 2. endothelial-specific MR (ECMR) deletion and epithelial sodium channel (ENaC) antagonism prevents leptin-induced endothelial impairment in females 3. endothelial cells of female mice and humans express more ECMR than males 4. ovariectomy blunts ECMR expression, which is restored by progesterone 5. ECMR expression correlates with progesterone levels in cycling and pregnant mice 6. protein kinase C (PKC) inhibition prevents progesterone-stimulated ECMR expression 7. pregnant mice develop pronounced endothelial dysfunction in response to leptin 8. placental ischemia induces elevated leptin and aldosterone levels in pregnant rats. Therefore, we hypothesized that endothelial progesterone receptor activation upregulates ECMR expression which mediates leptin-induced endothelial dysfunction and hypertension in premenopausal and pregnant female mice. Three Specific Aims will rigorously test our hypothesis: 1 (K99): progesterone upregulates endothelial mineralocorticoid receptor expression via endothelial progesterone receptor activation, 2 (K99): endothelial mineralocorticoid receptors mediate leptin-induced endothelial dysfunction and hypertension in female mice, 3 (R00 Independent): leptin-induced, aldosterone-mediated activation of mineralocorticoid receptors contributes to endothelial dysfunction and hypertension in obese preeclampsia. We will utilize novel transgenic mouse models (deficiency of endothelial-specific progesterone receptors and ENaC), endothelial cell culture techniques investigating progesterone-mediated PKC mechanisms and work with experts in the field to determine the regulation and functional relevance of ECMR in leptin- mediated endothelial dysfunction and hypertension in premenopausal females. Furthermore, in the independent phase, we will shift the approach utilizing the reduced uterine perfusion pressure mouse model of placental ischemia to a groundbreaking study of the role of leptin in hypertensive pregnancy. The results of these studies will further our knowledge of sex specific mechanisms of endothelial dysfunction and hypertension in females and may lead to improved treatment strategies for obese pregnant and non-pregnant women. Furthermore, the resources provided by mentors on this application, the environment at Augusta University and the training plan enclosed will advance the applicant toward the goal of transitioning to independent researcher.