Investigating the molecular determinants of cerebral cavernous malformations downstream of MEKK3-KLF2/4 signaling

项目总结： 脑海绵状血管畸形(CCM)是一种薄壁、扩张的血管畸形。 主要发生在中枢神经系统，是出血性中风和癫痫发作的主要原因。目前，没有 这种进行性疾病的医学治疗方法不是侵入性神经外科。CCMS是由遗传基因引起的 导致负调控MEKK3所需的异三聚体接头复合体丢失的突变 脑血管内皮细胞信号转导与KLF2、KLF4转录因子的表达最近，我们 已经确定内皮细胞Toll样受体4(TLR4)和肠道微生物群是关键的上游刺激因子 MEKK3信号。然而，这一途径的下游效应与疾病的发病机制有关 都还没有确定。在CCM病的新生小鼠模型中，我们观察到 ADAMTS金属蛋白酶的转录和ADAMTS介导的ECM蛋白多糖的加工， 维西肯，作为CCM发展的早期事件。这一提议将检验MEKK3-KLF2/4的假设 信号调节基质环境，通过ADAMTS蛋白酶介导多种加工，以促进 CCM队形。通过使用体内遗传小鼠模型和体外模型系统，我们将 研究ADAMTS蛋白水解酶(Aim 1)及其底物Verscan(Aim 2)作为候选蛋白的作用 这一因果MEKK3通路的下游靶点。预计这些研究将对 驱动病变发生和发现所需的分子分子可能被用来指导 CCM病的机制治疗。

Project Summary: Cerebral cavernous malformations (CCMs) are thin-walled, dilated vascular abnormalities that occur predominantly in the CNS and are a major cause of hemorrhagic strokes and seizures. Presently, there are no medical therapies for this progressive disease other than invasive neurosurgery. CCMs are caused by genetic mutations that result in the loss of a heterotrimeric adaptor complex required to negatively regulate MEKK3 signaling and the expression of the KLF2 and KLF4 transcription factors in brain endothelial cells. Recently, we have identified endothelial Toll-like receptor 4 (TLR4) and the gut microbiome as critical upstream stimulators of MEKK3 signaling. However, the downstream effectors of this pathway relevant to disease pathogenesis have yet to be identified. In the neonatal mouse model of CCM disease, we have observed increased transcription of ADAMTS metalloproteases and ADAMTS-mediated processing of the ECM proteoglycan, versican, as early events in CCM development. This proposal will test the hypothesis that MEKK3-KLF2/4 signaling regulates the matrix environment, mediating versican processing by ADAMTS proteases, to promote CCM formation. Through the use of in vivo genetic mouse models and in vitro model systems, we will investigate the role of ADAMTS proteases (Aim 1) and their substrate, versican (Aim 2), as candidate downstream targets of this causal MEKK3 pathway. These studies are expected to yield new insights into the molecular molecules required to drive lesion genesis and findings may be used to direct the development of mechanism-based therapeutics for CCM disease.