Targeting Mitochondrial Cyclophilin D in Vascular Oxidative Stress and Hypertension

项目摘要 在西方社会，高血压是一个主要的健康问题，也是中风、心肌梗塞和 心力衰竭和专门针对线粒体的治疗代表了降低靶向的有希望的策略- 器官受损。线粒体通透性转换孔(MPTP)在线粒体功能障碍中起关键作用 高血压的靶器官损害。我们发现，亲环素D(CypD)的耗尽或抑制 调节MPTP开放的亚基，改善血管功能，降低高血压。同时， CypD的组织特异性作用和CypD激活的分子机制尚不清楚。在拟议的研究中， 我们将通过确定血管CypD的作用和靶向CypD的治疗潜力来推进这项工作 内皮功能障碍和高血压。我们对高血压病患者的研究显示CypD 由于GCN5L1乙酰化转运失衡导致K166乙酰化导致CypD过度乙酰化和CypD激活 酶活性降低，SIRT3脱乙酰酶活性降低。SIRT3被高活性的线粒体脂质二羰基灭活， Isoevuglandins(IsoLG)，而IsoLG清除可阻止CypD乙酰化并降低高血压。我们建议 以线粒体CypD为靶点，抑制氧化应激，改善血管功能，降低高血压。这个 这项建议的总体目标是确定CypD介导的血管氧化应激的具体机制 并测试靶向CypD对高血压的治疗潜力。我们将致力于实现以下目标： 目的1.验证内皮细胞和平滑肌细胞特异性CypD缺失减少血管的假说 氧化应激，保护血管松弛，减轻高血压。在这个目标中，我们将研究 CypD缺失在可诱导内皮特异性CypD基因敲除(EcCypDKO)和平滑中的保护作用 肌肉特异性CypD基因敲除(SmcCypDKO)小鼠，采用Angii和DOCA-SALT高血压模型。 目的2.验证CypD-K166乙酰化导致血管功能障碍和高血压的假说。我们 将使用新的脱乙酰基模拟物确定CypD-K166乙酰化的病理生理学意义 CypD-K166R突变小鼠、新的内皮特异性GCN5L1基因敲除小鼠(EcGCN5L1KO)和内皮 特异性SIRT3基因敲除小鼠(EcSirt3KO)。所有的老鼠都在我们的实验室里。 目的3.验证高血压发病后CypD抑制和阻断CypD高乙酰化的假说 改善血管功能。我们将测试CypD阻滞剂是否能改善血管功能和降低血液 高血压小鼠的血压。我们将研究从人类分离的阻力动脉中的CypD乙酰化 研究对象为高血压病患者，并测试CypD阻滞剂是否能改善人体内皮功能。 我们处于进行这些跨学科研究的理想位置。我们培育了新的CypD转基因小鼠 模型和针对线粒体的治疗。我们可以接触到人类血管组织和独特的专业知识 在氧化应激、人类血管研究和高血压方面。我们的数据有力地支持了这一新的途径 血管功能障碍，这项工作有可能对新疗法的开发产生重大影响。

Project Summary Hypertension is a major health problem in Western Societies and a risk factor for stroke, myocardial infarction, and heart failure and therapies specifically targeted at mitochondria represent promising strategies to reduce target- organ-damage. Mitochondrial permeability transition pore (mPTP) plays a key role in mitochondrial dysfunction and target-organ-damage in hypertension. We discovered that depletion or inhibition of Cyclophilin D (CypD), a regulatory subunit of mPTP opening, improves vascular function and attenuates hypertension. Meanwhile, the tissue specific role of CypD and molecular mechanisms of CypD activation are not known. In the proposed studies, we will take this work forward by defining the role of vascular CypD and therapeutic potential to target CypD in endothelial dysfunction and hypertension. Our studies in human subjects with essential hypertension showed CypD hyperacetylation and implicate CypD activation by K166 acetylation due to imbalance between GCN5L1 acetyltransfe- rase and reduced Sirt3 deacetylase activity. Sirt3 is inactivated by highly reactive mitochondrial lipid dicarbonyls, isolevuglandins (isoLG), while isoLG scavenging prevents CypD acetylation and reduces hypertension. We propose targeting mitochondrial CypD to inhibit oxidative stress, improve vascular functions and reduce hypertension. The overall objective of this proposal is to define specific mechanisms of CypD mediated vascular oxidative stress and test the therapeutic potential of targeting CypD in hypertension. We will pursue the following aims: AIM 1. To test the hypothesis that cell specific CypD depletion in endothelial and smooth muscle reduces vascular oxidative stress, protects vascular relaxation and attenuates hypertension. In this aim we will examine the protective role of CypD depletion in inducible endothelial specific CypD knockout (EcCypDKO) and smooth muscle specific CypD knockout (SmcCypDKO) mice using AngII and DOCA-salt models of hypertension. AIM 2. To test the hypothesis that CypD-K166 acetylation contributes to vascular dysfunction and hypertension. We will define the pathophysiological significance of CypD-K166 acetylation using new deacetylation mimic CypD-K166R mutant mice, new endothelial specific GCN5L1 knockout mice (EcGCN5L1KO), and endothelial specific Sirt3 knockout mice (EcSirt3KO). All mice are available in our lab. AIM 3. To test the hypothesis that CypD inhibition and blocking CypD hyperacetylation after onset hypertension improve vascular function. We will test if CypD blockers improve vascular function and reduce blood pressure in hypertensive mice. We will study CypD acetylation in resistance arteries isolated from human subjects with essential hypertension and test if CypD blockers improve human endothelial function. We are in an ideal position to perform these interdisciplinary studies. We developed new CypD transgenic mouse models and mitochondria-targeted treatments. We have access to human vascular tissue and unique expertise in oxidative stress, human vascular studies and hypertension. Our data strongly support this novel pathway in vascular dysfunction, and this work has the potential to make a major impact on the development of new treatments.