Potentiation of CAA-mediated endothelial dysfunction by cardiovascular risk factors

项目摘要/摘要 脑血管受损会导致阿尔茨海默病(AD)和痴呆症。在……里面 除脑淀粉样血管病变(CAA)外，90%以上的AD患者和许多 认知正常的老年人，慢性心血管(CV)危险因素也已知会损害大脑 微血管功能。然而，CAA与慢性心血管危险因素的交互作用以及 它们导致脑血管功能障碍和认知功能减退的机制尚不清楚。 明白了。我们的初步工作确定了淀粉样β蛋白(Aβ)介导的分子机制 脑内皮细胞功能障碍。我们建议澄清β和过度表达/激活之间的相互作用 TRAIL(肿瘤坏死因子相关的凋亡诱导配体)死亡受体(DR)DR4和DR5，未知的靶点 对细胞应激/死亡的巨大影响。DR激活触发线粒体功能障碍，释放前- 细胞凋亡因子和活性氧(ROS)。耐人寻味的是，慢性心血管风险因素与 脑血管病理，如低灌注率、高血压和高同型半胱氨酸血症(HHC)， 导致类似的EC死亡和线粒体功能障碍途径。我们将检验这一假设 慢性心血管危险因素，如高血压、HHC和低灌注率，协同增强 脑血管Aβ在慢性再生障碍性贫血中促进TRAIL-DR活化和线粒体功能障碍的作用 在大脑内皮细胞中，从而导致阿尔茨海默病的神经血管单位衰竭。在……里面 目的1、利用体外培养的人脑血管内皮细胞，验证慢性心血管危险因素的假设 增加内皮细胞对Aβ的脆弱性，增强DR和线粒体介导的途径。我们会 分析低灌注量和高密度脂蛋白在β介导的内皮DR激活中的相对贡献， 线粒体毒性和血脑屏障通透性通过分子、生化和成像方法。在目标2中， 我们将在体内测试慢性心血管危险因素增强DR和线粒体介导的假说 淀粉样变性小鼠模型中内皮功能障碍和脑血管淀粉样蛋白负荷增加， 会导致神经血管和认知障碍。我们将在Tg2576小鼠身上评估这些机制 在CAA发生之前或之后暴露于慢性心血管危险因素(高血压或HHC)。我们会 检查这些应激途径对血脑屏障功能障碍、微出血、淀粉样蛋白沉积、 神经免疫激活和认知功能。在目标3中，我们将检验这样一个假设，即操纵 减少DR激活(DR沉默)和线粒体功能障碍(碳酸氢酶抑制剂)将 预防或逆转Aβ和Chronic联合应用所致的内皮损伤和血脑屏障通透性 脑血管挑战与心血管疾病风险有关。这项研究将揭示可修改的分子机制。 潜在的混合性脑血管病和痴呆症，对临床实践和 公共卫生。

Project Summary/Abstract Damage to the brain vasculature significantly contributes to Alzheimer's disease (AD) and dementia. In addition to Cerebral Amyloid Angiopathy (CAA), which is present in more than 90% of AD patients and in many cognitively normal elderly people, chronic cardiovascular (CV) risk factors are also known to impair brain microvascular function. However, the interactive nature of CAA and chronic CV risk factors and the mechanisms through which they contribute to cerebrovascular dysfunction and cognitive decline are poorly understood. Our preliminary work identified molecular mechanisms responsible for amyloid beta (Aβ)-mediated brain endothelial dysfunction. We propose to clarify the interplay between Aβ and overexpression/activation of the TRAIL (TNF-related apoptosis inducing ligand) death receptors (DR) DR4 and DR5, unexplored targets of enormous impact for cell stress/death. DR activation triggers mitochondrial dysfunction, with release of pro- apoptotic factors and reactive oxygen species (ROS). Intriguingly, chronic CV risk factors associated with cerebrovascular pathology, such as hypoperfusion, hypertension and hyperhomocysteinemia (HHC), contribute to similar EC death and mitochondrial dysfunction pathways. We will test the hypothesis that chronic CV risk factors, such as hypertension, HHC, and hypoperfusion, synergistically potentiate the effects of cerebrovascular Aβ in CAA, enhancing TRAIL DR activation and mitochondrial dysfunction in cerebral endothelial cells, and thus leading to neurovascular unit failure in Alzheimer's disease. In Aim 1, using human cerebral endothelial cells in vitro, we will test the hypothesis that chronic CV risk factors increase endothelial vulnerability to Aβ, potentiating DR- and mitochondria-mediated pathways. We will analyze the relative contribution of hypoperfusion and HHC to Aβ-mediated endothelial DR activation, mitochondrial toxicity and BBB permeability through molecular, biochemical and imaging approaches. In Aim 2, we will test in vivo the hypothesis that chronic CV risk factors potentiate DR- and mitochondria-mediated endothelial dysfunction and increase cerebrovascular amyloid burden in a mouse model of amyloidosis, contributing to neurovascular and cognitive impairment. We will assess these mechanisms in Tg2576 mice exposed to chronic CV risk factors (hypertension or HHC) before or after the development of CAA. We will examine the effects of these stress pathways on BBB dysfunction, microhemorrhages, amyloid deposition, neuroimmune activation, and cognitive function. In Aim 3 we will Test the hypothesis that manipulations that decrease DR activation (DR silencing) and mitochondrial dysfunction (carbonic anhydrase inhibitors) will prevent or reverse endothelial damage and BBB permeability induced by the combination of Aβ and chronic cerebrovascular challenges that occur with CV risk. This study will reveal modifiable molecular mechanisms underlying mixed cerebrovascular disease and dementia, which have enormous impact on clinical practice and public health.