Notch, LRP, and MMP in Stroke and Vascular Dementia

描述（由申请人提供）： 中风和血管性痴呆是退伍军人群体中重要的致残性疾病。预防中风有可能产生巨大的影响，但绝大多数中风研究都集中在中风后发生的过程上。为了确定导致中风的分子过程，我们研究了原型人类疾病大脑常染色体显性遗传性动脉病伴皮质下白质脑病（CADASIL），这是一种由Notch 3突变引起的遗传性中风/痴呆疾病。CADASIL的标志性病理特征包括：动脉细胞外基质稀薄、动脉颗粒状嗜锇物质（GOM）沉积和血管Notch 3蛋白积聚。本研究的目的是确定导致这些异常的分子过程。初步数据表明，Notch 3和LRP 1（一种以其内吞功能而闻名的蛋白质）之间存在特定的物理和功能相互作用。我们将检验以下假设：在CADASIL中，脑血管中的突变型Notch 3损害Notch 3的LRP 1内吞作用，导致Notch 3积聚和MMP表达增加。我们建议如下：CADASIL中的突变Notch 3功能障碍性地结合LRP 1，导致LRP 1功能障碍; LRP 1减少导致关键细胞外蛋白（包括Notch 3和MMP）的内吞作用受到抑制。我们建议在三个具体目标中测试这种假设的事件级联。首先，我们将在分子水平上确定突变型Notch 3蛋白与LRP 1的相互作用是否不同（与WT Notch 3相比）。其次，我们将在细胞培养中确定突变型Notch 3是否抑制LRP 1依赖性内吞作用。第三，我们将定量Notch 3在缺乏参与LRP 1内吞作用的关键基因的转基因小鼠中的积累，以测试LRP 1是否是体内突变Notch 3的真正靶标。这些研究可能揭示预防中风和血管性痴呆的重要目标。大量文献已经支持LRP 1和MMPs在卒中后的作用。这些研究可能确定LRP 1和MMP在卒中前血管病理学中的额外作用，并可能为卒中和血管性痴呆预防治疗提供新方法。

DESCRIPTION (provided by applicant): Stroke and vascular dementia are important disabling disorders among the veteran population. Prevention of stroke has the potential to make a great impact, but a vast majority of stroke studies have focused on processes that occur after stroke. To identify molecular process which lead to stroke, we study the prototype human disorder Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL), a hereditary stroke/dementia disorder caused by mutations in Notch3. Hallmark pathological features of CADASIL include: rarefication of arterial extracellular matrix, arterial granular osmiophilic material (GOM) deposition, and vascular Notch3 protein accumulation. The objective of this study is to define molecular processes that cause these abnormalities. Preliminary data demonstrates specific physical and functional interactions between Notch3 and LRP1, a protein known for its endocytic function. We will test the hypothesis that in CADASIL, mutant Notch3 in cerebral vessels impairs LRP1 endocytosis of Notch3, leading to Notch3 buildup and increased MMP expression. We suggest the following: mutant Notch3 in CADASIL dysfunctionally binds to LRP1, leading to LRP1 malfunction; decreased LRP1 results in inhibition of endocytosis of critical extracellular proteins, including Notch3 and MMPs. We propose to test this hypothetic cascade of events in three specific aims. First, we will determine at the molecular level whether mutant Notch3 proteins interact differently with LRP1 (compared to WT Notch3). Second, we will determine in cell cultures whether mutant Notch3 inhibits LRP1 dependent endocytosis. Third, we will quantitate Notch3 buildup in transgenic mice lacking key genes that participate in LRP1 endocytosis to test whether LRP1 is a true target of mutant Notch3 in vivo. These studies may shed light on important targets for prevention of stroke and vascular dementia. A vast literature already support a role for LRP1 and MMPs after stroke. These studies may identify an additional role for LRP1 and MMPs in vascular pathology prior to stroke and perhaps suggest novel methods for stroke and vascular dementia prevention therapy.