Molecular Dissecfion of NF1 Vasoocclusive and Aneurysm Disease

神经纤维瘤病由编码蛋白质神经纤维蛋白的NF 1肿瘤抑制基因的突变引起。血管病变是NF 1患者发病率和死亡率的一个未被充分认识的来源。NFl患者发生血管病变，包括动脉闭塞和动脉瘤。尽管有这些观察结果，但神经纤维蛋白在协调内皮细胞（EC）、血管平滑肌细胞（VSMC）和骨髓源性细胞（BMDC）之间的复杂相互作用以维持体内血管壁稳态方面的功能尚不完全清楚。本申请中概述的研究将直接解决这种知识的缺乏，并且对于理解NF 1血管疾病的发病机制、实验治疗的合理设计以及开发新的生物标志物以预测NF 1患者在突发心血管失代偿之前的早期血管疾病是必要的。我们开发了动脉闭塞和动脉瘤形成的新型基因工程小鼠模型，其概括了人NF 1表型。利用谱系限制的转基因小鼠消融EC、VSMC和BMDC中的Nfl，我们提供了初步数据来支持Nfl +/-巨噬细胞和细胞外基质蛋白骨桥蛋白的上调是Nfl动脉闭塞的主要效应物的假设。在建立了NF 1动脉瘤的第一个动物模型后，我们还提供了初步证据来支持神经纤维蛋白缺陷的VSMC、EC或BMDC和骨桥蛋白的上调协调NF 1动脉瘤形成的假设。因此，具体目标是：（1）使用谱系限制的转基因小鼠，我们将特异性地消除骨髓细胞中的Nfl，以检验单核细胞/巨噬细胞中Nfl的杂合失活直接导致Nfl +/-小鼠中新生内膜形成增加的假设。（2）使用谱系限制的转基因小鼠和骨髓移植两者，以特异性地缺失VSMC、EC或BMDC中的Nfl的一个等位基因，我们将确定哪种特定的细胞谱系对于体内动脉瘤形成的增加是关键的。(3)为了检验骨桥蛋白上调加速Nf 1 +/-小鼠体内新生内膜和动脉瘤形成的假设，我们将使OPN -/-和Nf 1 +/-小鼠杂交以产生复合突变体。

Neurofibromatosis results from mutations in the NFl tumor suppressor gene, which encodes the protein neurofibromin. Vasculopathies constitute an under-recognized source of morbidity and mortality in NF1 patients. NFl patients develop vascular lesions including arterial occlusions and aneurysms. Despite these observations, the function of neurofibromin in coordinating the complex interactions between endothelial cells (ECs), vascular smooth muscle cells (VSMCs), and bone marrow derived cells (BMDCs) for maintainance of blood vessel wall homeostasis in vivo is incompletely understood. Studies outlined in this application will directly address this lack of knowledge and are imperative for understanding the pathogenesis of NF1 vascular disease, rational design of experimental therapeutics, and development of novel biomarkers to predict early vascular disease in NF1 patients prior to sudden cardiovascular decompensation. We developed novel genetically engineered mouse models of both arterial occlusion and aneurysm formation, which recapitulates the human NFl phenotype. Utilizing lineage restricted transgenic mice to ablate Nfl in ECs, VSMCs and BMDCs, we provide preliminary data to support that hypothesis that Nf1 +/- macrophages and upregulation of extracellular matrix protein osteoponfin are the primary effectors of NFl arterial occlusion. Having established the first animal model of NFl aneurysms, we also provide preliminary to support the hypothesis that either neurofibromin deficient VSMCs, ECs or BMDCs and upregulation of osteoponfin orchestrate NFl aneurysm formation. Therefore the specific aims are: (1) Using lineage-restricted transgenic mice, we will specifically ablate Nfl in myeloid cells to test the hypothesis that heterozygous inactivation of Nfl in monocyte/macrophages directly leads to increased neointima formation in Nf1 +/- mice (2) Using both lineage-restricted transgenic mice and bone marrow transplantation to specifically delete one allele of Nf1 in either the VSMCs, ECs or BMDCs, we will determine which specific cell lineage is critical for increased aneurysm formation in vivo. (3) To test the hypothesis that upregulation of osteoponfin accelerates neointima and aneurysm formation in Nf1 +/- mice in vivo, we will intercross OPN -/- and Nf1 +/- mice to generate compound mutants.