Signaling Aberrations and Cerebral Cavernous Malformation Pathogenesis

 描述(申请人提供)：脑海绵状畸形(CCM)是一种常见的血管畸形，易患中风和其他神经后遗症的终身风险。皮损发生在零星形式或常染色体显性遗传形式，后者是由于三个基因中的一个发生突变。Awad和Marchuk实验室对手术切除的CCM病变进行的分子遗传学分析发现，血管腔内皮细胞存在二次打击体细胞CCM基因突变，提示CCM的发病机制为二次打击突变。利用这些知识，我们建立了健壮的CCM动物模型，概括了人类病变的组织学、分子特征和超微结构。虽然我们现在可以描述病变发病的主要阶段，但调节这些阶段进展的潜在分子开关仍然未知。在平行的工作中，金斯伯格和其他实验室已经证明，CCM基因功能的丧失会损害内皮细胞连接，这在一定程度上受到RhoA/ROCK活性的调节。然而，Ginsberg、Kahn和其他实验室的研究表明，CCM功能的丧失会改变其他主要的信号通路，如Notch、Wnt/？catenin、FOXO1和KFl2/MEKK2信号。RhoA/ROCK活性在CCM发病机制中的中心地位以及其最佳治疗靶点(S)仍不清楚。我们对这一P01方案的中心假设是CCM蛋白的丢失通过多个异常信号通路促进病变的形成，其中一些是RhoA/ROCK不依赖的。我们进一步提出，不同的信号和遗传异常调节病变发展和成熟的不同阶段。我们建议分析病变发展过程中的分子遗传学事件，并研究体内和体外的相关信号。我们的小鼠模型使我们能够在体内研究这些通路在CCM发病机制不同阶段的作用，我们收集的手术切除的CCM使我们能够在临床相关的成熟人类病变中验证这些发现。对小鼠和人类损伤的体外、体内和详细分析的连续性将有助于我们创建与损伤发病机制相关的异常信号网络的有序方案，并将新的基本见解转化为合理的治疗策略。

 DESCRIPTION (provided by applicant): The cerebral cavernous malformation (CCM) is a common vascular anomaly, predisposing to a lifetime risk of stroke and other neurologic sequelae. Lesions occur in either a sporadic form or in an autosomal- dominant inherited form, the latter due to mutation in one of three genes. Molecular genetic analyses of surgically resected CCM lesions by the Awad and Marchuk laboratories has uncovered second-hit somatic CCM gene mutations in endothelial cells lining the vascular caverns, suggesting a two-hit mutational mechanism of CCM pathogenesis. Using this knowledge, we have developed robust animal models of CCM recapitulating the histology, molecular signatures and ultrastructure of the human lesions. Although we can now describe the major stages of lesion pathogenesis, the underlying molecular switches that modulate the progression of these stages remain unknown. In parallel work, the Ginsberg and other laboratories have shown that loss of CCM gene function impairs endothelial cell junctions, in part regulated by RhoA/ROCK activity. Yet, the Ginsberg, Kahn, and other laboratories have shown that loss of CCM function alters other major signaling pathways such as Notch, Wnt/ß-catenin, FOXO1, and KFL2/MEKK2 signaling. The centrality of RhoA/ROCK activity in CCM pathogenesis, and hence its optimal therapeutic target(s), remain unknown. Our central hypothesis of this P01 proposal is that the loss of CCM proteins contributes to lesion formation via multiple aberrant signaling pathways, some of which are RhoA/ROCK-independent. We further propose that different signaling and genetic aberrations modulate distinct stages of lesion development and maturation. We propose to analyze molecular genetic events during lesion development, and investigate associated signaling in vivo and in vitro. Our murine models enable us to investigate the role of these pathways in vivo at the different stages of CCM pathogenesis, and our collection of surgically resected CCMs allows us to validate these findings in the clinically relevant mature human lesion. The continuum of in vitro, in vivo and detailed analysis of mouse and human lesions will help us create an ordered scheme of aberrant signaling networks in relation to lesion pathogenesis, and translate new fundamental insights into rational therapeutic strategies for this disease.