Molecular Pathogenesis of Hereditary Hemorrhagic Telangiectasia

项目总结/摘要 动静脉（AV）畸形（AVM）是将血液从动脉直接分流到血管的血管异常。 导致器官功能障碍AVM的发病机制知之甚少，限制了AVM的合理设计。 分子干预。我们的长期目标是为AVM开发更好的治疗方法， 治疗选择有限且有风险。我们的策略是专注于脑AVM（BAVM），因为它们是最常见的 危险的AVM，BAVM的发现适用于身体其他部位的AVM。大多数BAVM是 散发的，但遗传性BAVM，如遗传性出血性毛细血管扩张症（HHT），提供了一个 这是研究疾病过程的分子机制的绝佳机会。HHT是常染色体 显性遗传性疾病，特征为全身（包括大脑）多灶性AVM。 激活素受体样激酶（ALK 1）的突变导致2型HHT（HHT 2），其代表25- 57%的HHT病例。Alk 1是BMP配体的I型TGFβ受体，并且Alk 1通过其作用的机制 导致AVM的原因知之甚少。基于我们强大的初步数据，我们建议建立一个新的 HHT 2-BAVM小鼠模型，用于鉴定AVM发病机制的关键分子调节剂，使用 既有针对性的方法，又有无偏见的全基因组表达谱。为此，我们建议 建立一个急需的强大的临床前动物模型，忠实地模拟疾病的某些方面 HHT 2患者的症状。现有的HHT小鼠模型在再现临床上是有限的。 表现。使用最先进的策略，我们已经开发了一种有用的HHT 2-BAVM小鼠模型， 在脑内皮细胞中特异性地删除两个Alk 1等位基因，并获得了强有力的初步数据， 这种缺失导致了强大的BAVM、颅内血管扩张和神经学后果， 身体其他部位的可检测缺陷。我们将首先充分利用创新，高- 分辨率双光子成像通过颅窗进入活脑中的血管系统，实现 5D透视图（3D血管结构加上随时间变化的血流速度）。W候选人 促进BAVM形成的分子调节剂，包括AV编程，内皮屏障， Alk 1基因缺失小鼠的炎症、内皮细胞向间质细胞转化和超氧化物生成 脑内皮细胞最后，我们将进行尖端的基因组表达谱分析，以阐明Alk 1 靶基因，然后使用生物信息学工具根据其功能对鉴定的基因进行分类， 特色我们提出的目标包括技术和概念创新的结合， 进一步了解AVM形成和HHT发病机制的分子机制。我们 这项工作将为这些疾病建立一个强大的临床前模型，揭示新的分子机制， 潜在的疾病病因，并影响HHT和BAVM患者的未来临床实践。 e还将调查

PROJECT SUMMARY/ABSTRACT Arteriovenous (AV) malformations (AVMs) are vascular anomalies that shunt blood from an artery directly to a vein, causing organ dysfunction. AVM pathogenesis is poorly understood, limiting the rational design of molecular interventions. Our long-term goal is to develop better therapeutic treatments for AVMs, as current treatment options are limited and risky. Our strategy is to focus on brain AVMs (BAVMs), as they are the most dangerous AVMs, and findings in BAVM are applicable to AVMs elsewhere in the body. Most BAVMs are sporadic, but hereditary BAVMs, such as those seen in hereditary hemorrhagic telangiectasia (HHT), offer an excellent opportunity to study the molecular mechanism underlying disease processes. HHT is an autosomal dominant genetic disorder characterized by multifocal AVMs throughout the body, including the brain. Mutations in activin receptor-like kinase (ALK1) are responsible for Type 2 HHT (HHT2), which represents 25- 57% of all HHT cases. Alk1 is a type I TGFβ receptor for BMP ligands, and the mechanism through which Alk1 leads to AVMs is poorly understood. Building on our strong preliminary data, we propose to establish a novel HHT2-BAVM mouse model, with which to identify molecular regulators crucial for AVM pathogenesis, using both a targeted approach and unbiased genome-wide expression profiling. To this end, we propose to establish a much-needed robust preclinical animal model that faithfully models certain aspects of disease presentations in HHT2 patients. Existing mouse models of HHT are limited in recapitulating clinical manifestations. Using a cutting-edge strategy, we have developed a useful mouse model of HHT2-BAVM by deleting both Alk1 alleles specifically in brain endothelial cells, and have obtained strong preliminary data that this deletion results in robust BAVM, intracranial hemorrhages, and neurological consequences, without detectable defects elsewhere in the body. We will first fully characterize this model using innovative, high- resolution two-photon imaging through a cranial window to access the vasculature in live brains, achieving a 5D perspective (3D vascular structure plus blood velocity over time). W candidate molecular regulators that promote BAVM formation including AV programming, endothelial barrier, inflammation, endothelial-to-mesenchymal transition, and superoxide production in mice with Alk1 deletion in the brain endothelium. Finally, we will perform cutting-edge genomic expression profiling to elucidate Alk1 target genes, and then use bioinformatics tools to categorize identified genes based on their functional characteristics. Our proposed Aims comprise a combination of technical and conceptual innovations that will advance the knowledge of the molecular mechanisms underlying AVM formation and HHT pathogenesis. Our work will establish a robust preclinical model for these diseases, uncover new molecular mechanisms underlying the disease etiology, and impact future clinical practice for patients with HHT and BAVM. e will also investigate