Molecular Pathogenesis of Brain Arteriovenous Malformation

脑动静脉畸形的分子发病机制

• 批准号: 9242700
• 负责人: Rong Wang
• 金额: $ 34.7万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2019-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9242700
• 关键词: ACVRL1 gene; Adult; Aorta; Area; Arteries; Base of the Brain; Blood; Blood Vessels; Blood capillaries; Blood flow; Cardinal vein; Cephalic; Cerebrovascular system; Custom; Dangerousness; Data; Development; Disease; Dorsal; Down-Regulation; Embryo; Endothelial Cells; Epilepsy; Functional disorder; Genes; Genetic; Genetic Transcription; Genetic screening method; Goals; Hemorrhage; Human; Image; Imaging technology; Inherited; Investigation; Life; Ligands; Ligation; Measures; Mediating; Methods; Microscope; Molecular; Mus; Mutant Strains Mice; Mutation; Nitric Oxide; Nitric Oxide Synthetase Inhibitor; Nitroarginine; Operative Surgical Procedures; Pathogenesis; Pathology; Pathway interactions; Patients; Phenotype; Physiologic arteriovenous anastomosis; Physiology; Process; Radiation therapy; Regulation; Reporting; Resolution; Role; Signal Transduction; Stimulus; Stroke; Testing; Time; Up-Regulation; Veins; Venous; Work; brain arteriovenous malformations; capillary; design; endothelial dysfunction; fluorescence microscope; gain of function; gene function; genetic technology; hemodynamics; innovation; loss of function; loss of function mutation; middle cerebral artery; molecular marker; mutant; new therapeutic target; notch protein; novel; postnatal; public health relevance; response; shear stress; success; therapeutic target; two-photon

 DESCRIPTION (provided by applicant): Brain arteriovenous (AV) malformations (BAVMs) can cause life-threatening strokes and have limited treatment options. The goal for this project is to elucidate the cellular and molecular mechanisms underlying BAVM pathogenesis to identify novel candidates as therapeutic targets to ameliorate this disease. AVMs are characterized by abnormal AV shunts that displace intervening capillaries. We propose a cross-disciplinary approach, fusing cutting-edge mouse genetics and imaging technologies, to test our hypothesis that Notch mutations can reprogram AV identity and alter AV differential nitric oxide (NO) signaling, and thus endothelial dysfunction, to elicit BAVMs. Notch receptors and ligands are expressed in arteries but not veins. Notch signaling promotes arterial at the expense of venous differentiation by enhancing arterial and suppressing venous molecular markers. We have reported that endothelial expression of a constitutively active Notch4 mutation (Notch4*) elicits BAVMs in mice. Notch4* reprograms veins to gain arterial and lose venous molecular identity, and correcting the causal Notch4* leads to normalization of established BAVMs. We have built a custom two-photon microscope, optimal for structural and hemodynamic imaging of cerebral vasculature in live mice. We can thus obtain 5D data (3D plus blood velocity over time) through a cranial window to reveal the process of BAVM formation in mice. Built on our strong background and preliminary data, we propose: Aim 1 - Determine the effect of endothelial Notch4* on venous endothelial dysfunction and BAVM formation. We will test our hypothesis that Notch4* upregulates NO levels in the veins, alters venous endothelial response to blood flow, and thus permits AVM formation. We will examine the effect of Notch4* on venous NO signaling, endothelial response to blood flow, and flow mediated BAVM formation; Aim 2 - Determine the effect of endothelial Notch deficiency on arterial endothelial dysfunction and BAVM formation. We will test our hypothesis that loss of endothelial Notch gene function reduces arterial NO signaling, leading to arterial dysfunction and thus AVMs. We will analyze mice with endothelial deletion of Rbpj for BAVM pathology, arterial NO signaling, and endothelial response to blood flow stimuli; Aim 3 - Compare Notch and Alk1 mouse mutants in DA and CV development and BAVM formation. We will test our hypothesis that Notch interacts with Hereditary Hemorrhagic Telangectasia (HHT) 2 (or Alk1) in AV differentiation and AVM formation. We will compare the Notch and HHT mutant phenotypes using two-photon imaging and 3D rendering and perform genetic rescue. The findings from this study will conceptually advance our understanding of the cellular and molecular mechanisms of AVM pathogenesis, reveal novel functions for Notch in regulating the unique physiology of arteries and veins, and uncover interactions between the Notch and HHT pathways. The success of this work will inspire new areas of investigation in the fields of AVMs, Notch signaling, and vascular pathophysiology.

 描述（由申请人提供）：脑动静脉（AV）畸形（BAVM）可导致危及生命的中风，且治疗选择有限。该项目的目标是阐明 BAVM 发病机制的细胞和分子机制，以确定新的候选药物作为改善这种疾病的治疗靶点。 AVM 的特点是异常的 AV 分流会取代介入的毛细血管。我们提出了一种跨学科的方法，融合了尖端的小鼠遗传学和成像技术，来检验我们的假设，即 Notch 突变可以重新编程 AV 身份并改变 AV 差异一氧化氮 (NO) 信号传导，从而导致内皮功能障碍，从而引发 BAVM。 Notch 受体和配体在动脉中表达，但在静脉中不表达。 Notch信号传导通过增强动脉和抑制静脉分子标记物来促进动脉分化，但以静脉分化为代价。我们已经报道，组成型活性 Notch4 突变 (Notch4*) 的内皮表达会在小鼠中引发 BAVM。 Notch4* 重新编程静脉以获得动脉分子特性并失去静脉分子特性，纠正因果性的 Notch4* 会导致已建立的 BAVM 正常化。我们构建了一种定制的双光子显微镜，最适合活体小鼠脑血管系统的结构和血流动力学成像。因此，我们可以通过颅窗获得 5D 数据（3D 加上血流速度随时间的变化），以揭示小鼠 BAVM 形成的过程。基于我们强大的背景和初步数据，我们建议： 目标 1 - 确定内皮 Notch4* 对静脉内皮功能障碍和 BAVM 形成的影响。我们将检验我们的假设，即 Notch4* 上调静脉中的 NO 水平，改变静脉内皮细胞对血流的反应，从而允许 AVM 形成。我们将检查 Notch4* 对静脉 NO 信号传导、内皮细胞对血流的反应以及血流介导的 BAVM 形成的影响；目标 2 - 确定内皮 Notch 缺陷对动脉内皮功能障碍和 BAVM 形成的影响。我们将检验我们的假设，即内皮 Notch 基因功能的丧失会减少动脉 NO 信号传导，导致动脉功能障碍，从而导致 AVM。我们将分析内皮缺失 Rbpj 的小鼠的 BAVM 病理学、动脉 NO 信号传导以及内皮对血流刺激的反应；目标 3 - 比较 Notch 和 Alk1 小鼠突变体的 DA 和 CV 发育以及 BAVM 形成。我们将检验我们的假设，即 Notch 与遗传性出血性毛细血管扩张 (HHT) 2（或 Alk1）在 AV 分化和 AVM 形成中相互作用。我们将使用双光子成像和 3D 渲染来比较 Notch 和 HHT 突变体表型，并进行基因拯救。这项研究的结果将从概念上推进我们对 AVM 发病机制的细胞和分子机制的理解，揭示 Notch 在调节动脉和静脉独特生理学方面的新功能，并揭示 Notch 和 HHT 通路之间的相互作用。这项工作的成功将激发 AVM、Notch 信号传导和血管病理生理学领域的新研究领域。