Cell Specific Mineralocorticoid Signaling, Insulin Resistance and Cardiovascular Stiffness

在我最后一次资助的VA优点中，我提议研究血管紧张素II（Ang II） II），醛固酮和WD（高饱和脂肪和精制碳水化合物单独和共同促进 雄性啮齿类动物心血管（CV）和骨骼肌组织中胰岛素（INS）抵抗。因为 提高NIH、VA、美国糖尿病协会和美国心脏协会的认识 关于让女性参与研究，我们在女性中开展了类似的工作。我们发现 这种饮食对女性的心血管影响更大。这与VA的翻译相关，因为 越来越多的女性退伍军人，因为在INS抵抗的条件下，如肥胖和2型糖尿病， 糖尿病，女性显示出CVD的风险大大增加。由于超重/肥胖的终生风险， 女性糖尿病发病率高，相关的心血管疾病已成为女性的主要健康问题。随着人们 肥胖和INS抵抗，他们表现出CV刚度增加，这是一种与增加的 CVD。心脏和脉管系统中的INS抗性导致生物可利用的一氧化氮（NO）减少， 与CV刚度增加相关。生物可利用的NO减少导致酶活性增加 转氨酶2（TG2），其增加胶原交联和相关的心脏和血管僵硬。 我们已经观察到，女性，而不是男性，发展CV僵硬后，只有8周的消费WD。 我们在WD诱导的INS抗性雌性小鼠模型中正在进行的工作也表明， 盐皮质激素受体（MR）阻断剂改善心脏和血管INS阻力和僵硬。我们有 获得的证据表明，选择性敲除雌性小鼠的内皮细胞（EC）MR， 在CV INS代谢信号传导和CV僵硬和由消耗WD诱导的松弛受损中， 周ECMR在CV INS信号传导和僵硬度性别相关差异发生中的作用 时间没有被探索。在这个提议中，我们的中心假设是ECMR激活促进CV INS阻力和刚度。这一假设的必然结果是INS代谢障碍 信号传导减少生物可利用的NO，这导致细胞外释放和TG2促进的激活。 女性和男性的胶原交联和CV刚度。在本修订提案中，我们计划 使用内皮特异性MR敲除小鼠的新型啮齿动物模型喂食WD，以及创新技术 以评估体内和离体的INS阻力和相关的CV刚度。在目标1中，我们将确定 ECMR介导的EC硬化的作用和INS代谢信号传导受损之间的关系 以及CV纤维化/僵硬和松弛受损。关系 ECMR介导的INS代谢信号传导受损和生物可利用的NO减少以及WD患者的CV僵硬度 喂老鼠。在目标2中，我们将确定ECMR介导的EnNaC激活在促进CV中的作用。 INS抵抗与血管和心脏纤维化/僵硬和松弛受损相关。我们预计 这项研究的结果将对肥胖和2型糖尿病患者的心血管疾病机制产生独特的见解 经验丰富的男性和女性，目标是将这些发现转化为治疗策略，以减少心血管疾病， 尤其是超重的INS抵抗男性和女性。

In my last funded VA merit I proposed to investigate novel molecular mechanisms by which angiotensin II (Ang II), aldosterone and a WD (high in saturated fat and refined carbohydrates individually and collectively promotes insulin (INS) resistance in cardiovascular (CV) and skeletal muscle tissue in male rodents. Because of the increasing awareness by the NIH, the VA, the American Diabetes Association and American Heart Association regarding incorporation of females in research, we performed comparable work in females. We have found that this diet has a more negative CV impact in females. This is of translational relevance to the VA because of increasing numbers of female veterans and because in conditions of INS resistance such as obesity and type 2 diabetes, women display a substantially increased risk for CVD. As the lifetime risk for overweight/obesity and diabetes in women is high, associated CVD in women has become a major health problem. As people become obese and INS resistant, they manifest increasing CV stiffness, an abnormality that tracks closely with increasing CVD. INS resistance in the heart and vasculature results in decreased bioavailable nitric oxide (NO) which is associated with increased CV stiffness. Reduced bioavailable NO results in increased activity of the enzyme transglutaminase 2 (TG2), which increases collagen crosslinking and associated heart and vascular stiffness. We have observed that females, but not males, develop CV stiffness after only 8 weeks of consumption of a WD. Our ongoing work in a female mouse model of INS resistance induced by a WD also demonstrates that mineralocorticoid receptor (MR) blockade improves heart and vascular INS resistance and stiffness. We have garnered evidence that selective knockout of the endothelial cell (EC) MR in female mice abrogates the reduction in CV INS metabolic signaling and CV stiffness and impaired relaxation induced by consumption of a WD for 16 weeks. The role of the ECMR in the genesis of sex-related differences in CV INS signaling and stiffness over time has not been explored. In this proposal, our central hypothesis is that ECMR activation promotes CV INS resistance and stiffness. The corollary to this hypothesis is that impairment in INS metabolic signaling reduces bioavailable NO, which results in extracellular release and activation of TG2 promoting collagen crosslinking and therefore CV stiffness in females and males. In this revised proposal we plan to use a novel rodent model of endothelial specific MR knockout mice fed a WD, as well as innovative techniques to access INS resistance and associated CV stiffness in vivo and ex vivo. In Objective 1, we will determine the role of ECMR-mediated EC stiffening and resultant relationship between impairment of INS metabolic signaling and CV fibrosis/stiffness and impaired relaxation in males and females consuming a WD. relationship between ECMR-mediated impairment of INS metabolic signaling and reduced bioavailable NO and CV stiffness in WD- fed mice. In Objective 2, we will determine the role of ECMR mediated EnNaC activation in promotion of CV INS resistance in relation to vascular and cardiac fibrosis/stiffness and impaired relaxation. We anticipate that results from this proposal will yield unique insights into the mechanisms of CVD in obese and type 2 diabetic Veteran men and women, with the goal of translating these findings into therapeutic strategies to reduce CVD, especially in overweight INS resistant men and women.