Targeting ADAM17 maturation in resistant hypertension.

在美国，55岁及以上人群的患病率高达55%，高血压（HTN）是一种高血压病。 心血管疾病（CVD）和全球死亡率的主要风险因素，因此仍然是 日益重要的医疗和公共卫生问题。脑内肾素-血管紧张素系统（RAS）在 维持正常血压（BP）和神经-心血管失调导致HTN 已经牢固确立。血管紧张素（Ang）-II通过其1型受体（AT 1 R）促进增加的 交感神经活性、盐和水重吸收、血管收缩、醛固酮和加压素释放 和炎症都是导致高血压的原因虽然我们小组和其他人的许多过度表达研究， 已经确定了ACE 2（血管紧张素转换酶2型）在预防进展方面的益处 并在实验模型中改善HTN的治疗，我们的小组是第一个证明ADAM 17 （一种去整合素和金属蛋白酶）介导神经源性HTN中的ACE 2脱落，从而减少ACE 2 小鼠和人类的代偿活动。ADAM 17介导的ACE 2脱落，这是一个蛋白质 胞外域从质膜上裂解并分泌到周围环境中， 在包括心脏和肾脏在内的许多组织中得到证实。ADAM 17被认为是介导神经炎症， 可溶性TNFα、IL-6反式信号转导、CX 3CL 1和其他细胞因子，但这一机制尚未在 神经源性高血压DOCA盐HTN与TNFα、IL-6水平升高和ACE 2活性降低相关 在大脑中，虽然从神经元中删除ADAM 17可以降低血压，恢复ACE 2活性并减少前 炎性细胞因子虽然ADAM 17被认为是炎症的主要药物靶标，但它的作用机制仍然存在。 选择性抑制剂的开发已经失败。最近的工作，被认为是革命性的，表明ADAM 17 成熟受到脑中菱形蛋白（神经元中的iRhom 1和小胶质细胞中的iRhom 2）的严格调节， 为新的目标定位策略打开了大门。因此，我们假设靶向ADAM 17成熟 将逆转神经源性HTN中的交感神经兴奋和神经炎症。我们将测试这个新的 在以下两个具体目标中确定目标的战略。 使用人类干细胞衍生的神经元和小胶质细胞的组合，独特的转基因和条件 敲除小鼠，在小胶质细胞中选择性缺失ADAM 17（Cx 3Cr 1 ERT 2-ADAM 17 tom），并靶向 敲低神经元（Rhom 1）或小胶质细胞（iRhom 2）中的ADAM 17成熟，这一研究的直接目标是 应用是：1）了解ADAM 17上调如何发生在整个前交感神经网络; 2)评估ADAM 17在神经炎症和小胶质细胞活化中的前馈作用;以及3）测试新的 临床相关的靶向策略，以防止ADAM 17激活和耐药HTN的发展。

With prevalence as high as 55% for individuals aged 55 and older in United States, hypertension (HTN) is a major risk factor contributing to cardiovascular diseases (CVD) and global mortality, hence remaining an increasingly important medical and public health issue. The role of the brain renin-angiotensin system (RAS) in the maintenance of normal blood pressure (BP) and in the neuro-cardiovascular dysregulation leading to HTN has been firmly established. Angiotensin (Ang)-II, by means of its type 1 receptor (AT1R), promotes increased sympathetic nerve activity, salt and water reabsorption, vasoconstriction, aldosterone and vasopressin release and inflammation, all contributing to HTN. While numerous overexpression studies, from our group and others, have established the benefits of ACE2 (Angiotensin Converting Enzyme type 2) in preventing the progression and improving the treatment of HTN in experimental models, our group was the first to demonstrate that ADAM17 (A Disintegrin And Metalloprotease) mediates ACE2 shedding in neurogenic HTN, thus reducing ACE2 compensatory activity in mice and humans. ADAM17-mediated ACE2 shedding, a process by which the protein ectodomain is cleaved from the plasma membrane and secreted into the surrounding milieu, has since been confirmed in many tissues including heart and kidney. ADAM17 is thought to mediate neuroinflammation through soluble TNFα, IL-6 trans-signaling, CX3CL1 and other cytokines, yet this mechanism has not been studied in neurogenic HTN. DOCA-salt HTN is associated with increased levels of TNFα, IL-6 and reduced ACE2 activity in the brain, while deletion of ADAM17 from neurons reduces BP, restores ACE2 activity and decreases pro- inflammatory cytokines. Although ADAM17 is thought to be a major drug target for inflammation, the development of selective inhibitors has failed. Recent work, deemed revolutionary, shows that ADAM17 maturation is tightly regulated by rhomboid proteins in the brain (iRhom1 in neurons and iRhom2 in microglia), opening the door for novel targeting strategies. Accordingly, we hypothesize that targeting ADAM17 maturation will reverse sympatho-excitation and neuro-inflammation in neurogenic HTN. We will test this new targeting strategy in the following two specific aims. Using a combination of human stem cells-derived neurons and microglia, unique transgenic and conditional knockout mice, with selective deletion of ADAM17 in microglia (Cx3Cr1ERT2-ADAM17tom) and targeted knockdown of ADAM17 maturation in neurons (Rhom1) or microglia (iRhom2), the immediate objectives of this application are to: 1) Understand how ADAM17 upregulation takes place throughout pre-sympathetic networks; 2) Assess the feed-forward role of ADAM17 in neuro-inflammation and microglia activation; and 3) Test new clinically-relevant targeting strategies to prevent ADAM17 activation and the development of resistant HTN.