Sex-specific fetal programming of adult vascular dysfunction and hypertension

描述(由申请人提供)：流行病学研究表明，怀孕不良的妇女所生的孩子患心血管疾病的风险增加，例如先兆子痫、多囊卵巢综合征、蛋白质或能量限制、肥胖、压力和吸烟，但其发病机制仍不完全清楚。作为这些妊娠病理中观察到的共同因素之一，母体睾酮(T)升高可能有助于CV疾病的胎儿程序化。事实上，我们最近的研究表明，母体T升高会导致子代大鼠发生高血压表型。为了了解这一机制，本项目提出了两个中心假设。首先，产前T可导致特定性别的高血压的发病和严重程度，而这些高血压反应是由出生后T水平的升高所介导的。第二，出生后T的增加通过血管平滑肌(VSM)蛋白激酶C(PKC)和血管内皮细胞EDHF/NO表达/功能的性别特异性功能障碍来诱导高血压反应。为了验证这些假设，我们在我们建立的怀孕大鼠模型中进行了一系列实验，并检查了它们的后代。提出了三个具体的目标：1)确定母亲T升高是否会导致子代高血压，男性的影响比女性更明显，以及出生后T的升高是否先于高血压的发生。我们将远程监测血压(BP)的渐进性变化并测量T水平，以建立高血压的发病和严重程度与出生后T水平变化之间的关系，从机械上确定出生后T水平升高是否是导致血压升高的关键因素。2)评价VSM的性别特异性高血压机制。我们将通过芯片和报告实验评估T与PKC启动子的结合来检测PKC同工酶在亚细胞组分中的表达谱、其磷酸化状态和功能活性，并探讨雄激素调节PKC表达的机制。3)剖析内皮功能受损的性别特异性机制。我们将通过检测EDHF组分SK3和IK1通道以及连接蛋白(CX37、CX40和CX47)的mRNA和蛋白水平、它们的亚细胞定位以及通过血管反应性和膜电位研究来评估EDHF介导的血管扩张受损的机制，从而研究EDHF和NO介导的血管扩张途径。我们将通过评估eNOS的表达、活性、NO的产生和信号事件来研究NO介导的血管扩张功能受损的作用。我们预计，在子宫内暴露T将通过上调不同的血管PKC同工酶和男性和女性血管中不同的内皮功能障碍而导致性别特异性高血压效应，这可能通过出生后T水平的变化来调节。这一结果将为理解成人心血管功能障碍的胎儿程序提供新的分子基础，并提高我们对血管功能障碍的性别差异的认识，为制定针对性别的高血压预防和治疗策略提供令人兴奋的机会。

DESCRIPTION (provided by applicant): Epidemiological studies show increased risk of cardiovascular (CV) diseases in children born to women with compromised pregnancies, such as in preeclampsia, PCOS, protein or energy restriction, obesity, stress, and smoking, but its pathogenesis remains incompletely understood. As one of the common factors observed in these pregnancy pathologies, elevated maternal testosterone (T) is likely to contribute to the fetal programming of CV disorders. Indeed, our recent studies demonstrate that elevated maternal T causes development of hypertensive phenotypes in rat offspring. To understand the mechanisms, 2 central hypotheses are proposed in this project. First, prenatal T induces sex-specific onset and severity of hypertension, and these hypertensive responses are mediated by postnatal increases in T levels. Second, increase in postnatal T induces hypertensive responses through sex-specific dysfunctions in vascular smooth muscle (VSM) protein kinase C (PKC) and endothelial EDHF/NO expression/function. To test these hypotheses, we propose a series of experiments in our established pregnant rat model and examine their offspring. Three specific aims are proposed: 1) Determine whether elevated maternal T programs offspring's hypertension, with more pronounced effect in males than females, and if postnatal T increase precedes hypertension onset. We will telemetrically monitor progressive changes in blood pressure (BP) and measure T levels to establish a relationship between onset and severity of hypertension and changes in postnatal T levels, mechanistically determining if postnatal T increase is the key contributing factor for BP increase. 2) Evaluate the sex-specific hypertensive mechanisms in VSM. We will examine the PKC isoenzyme expression profile in subcellular fractions, its phosphorylation status, and functional activity and examine mechanisms by which androgens regulate PKC expression by assessing binding of T to putative ARE in PKC promoter by ChiP and reporter assays. 3) Dissect the sex-specific mechanisms of impaired endothelial functions. We will examine the EDHF- and NO-mediated pathways and evaluate the mechanisms for impaired EDHF-mediated vasodilation by determining mRNA and protein levels of EDHF components SK3 and IK1 channels and connexins (CX37, CX40, and CX47), their subcellular localization, and functional activity using vascular reactivity and membrane potential studies. We will investigate the role of impaired NO-mediated vasodilator function by assessing the expression of eNOS, its activity, NO production, and signaling events. We expect that in utero T exposure will cause gender-specific hypertensive effects through upregulation of distinct vascular PKC isoenzymes and differential endothelial dysfunctions in the male and female vasculature, which may be regulated through postnatal changes in T levels. The results will provide a novel molecular basis to the understanding of fetal programming of adult CV dysfunction and improve our knowledge of sex differences in vascular dysfunction, providing an exciting opportunity to devise sex-specific strategies for prevention and treatment of hypertension.