Cell Specific Mineralocorticoid Signaling, Insulin Resistance and Cardiovascular Stiffness

在我上一次资助的VA功绩中，我提议研究血管紧张素II(Ang)通过 Ii)、醛固酮和WD(富含饱和脂肪和精制碳水化合物)单独和共同促进 雄性啮齿动物心血管和骨骼肌组织中的胰岛素抵抗。因为 提高美国国立卫生研究院、退伍军人管理局、美国糖尿病协会和美国心脏协会的认识 关于将女性纳入研究，我们在女性中进行了类似的工作。我们发现， 这种饮食对女性的简历有更负面的影响。这与退伍军人管理局具有翻译相关性，因为 越来越多的女退伍军人，因为在胰岛素抵抗的情况下，如肥胖和2型 糖尿病患者中，女性患心血管疾病的风险显著增加。因为超重/肥胖的终生风险和 女性糖尿病发病率高，与心血管疾病相关的女性已成为一大健康问题。随着人们变得 肥胖和胰岛素抵抗，他们表现为CV僵硬增加，这是一种与增加密切相关的异常 心血管疾病。INS在心脏和血管系统的抵抗导致生物可利用的一氧化氮(NO)减少 与增加的CV刚度相关联。生物可利用NO的减少会导致酶活性的增加 转谷氨酰胺酶2(TG2)，可增加胶原蛋白的交联度以及相关的心脏和血管硬度。 我们观察到，女性，而不是男性，在服用WD仅8周后就会出现CV僵硬。 我们正在进行的WD诱导的INS抵抗雌性小鼠模型中的工作也证明了 阻断盐皮质激素受体(MR)可改善心脏和血管胰岛素抵抗和僵硬。我们有 有证据表明，选择性敲除雌性小鼠内皮细胞(EC)MR可以消除这种减少 在慢性阻塞性肺疾病中，INS代谢信号和循环僵硬和16周摄入WD所致的松弛受损 几周。ECMR在CVINS信号和僵直Over性别差异发生中的作用 时间还没有被探索过。在这个提议中，我们的中心假设是eCMR激活促进了CV INS阻力和硬度。这一假说的推论是INS代谢障碍 信号转导减少了生物可利用的NO，从而导致细胞外释放和激活TG2促进 胶原蛋白的交联，因此在女性和男性的CV僵硬。在这份修订后的提案中，我们计划 使用喂食WD的内皮特异性MR基因敲除小鼠的新型啮齿动物模型以及创新技术 了解体内和体外的INS抵抗和相关的心血管僵硬。在目标1中，我们将确定 ECMR介导的内皮细胞硬化作用及其与INS代谢信号损伤的关系 在使用WD的男性和女性中，CV纤维化/僵硬和松弛受损。两者之间的关系 ECMR介导的INS代谢信号的损伤以及生物可利用的NO和CV僵硬的降低 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 胰岛素抵抗与血管和心脏纤维化/僵硬和松弛受损有关。我们预料到 这项提议的结果将对肥胖和2型糖尿病的心血管疾病的机制产生独特的见解 退伍军人的目标是将这些发现转化为治疗策略，以减少心血管疾病， 尤其是在超重的抵抗胰岛素的男性和女性中。

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.