The role of beta-catenin in the pathophysiology of infantile spasms

项目总结 婴儿痉挛(IS)，又称West综合征，是一种灾难性的儿童癫痫综合征 以痉挛为特征的，在生命的后期发展为癫痫发作。痉挛以自发性痉挛为典型 头部、颈部和四肢的屈曲/伸展，首先发生在4至8个月大的婴儿。海流 IS的治疗选择往往无效，并与显著的副作用相关。因此，小说 治疗策略至关重要。寻找新的治疗方法的一个限制因素是缺乏 临床前动物模型。我们鉴定并鉴定了一种具有多种表型的新型啮齿动物模型。 人类的特点是。该模型是通过饲养雄性小鼠而产生的，这些雄性小鼠含有一种带牙线的 Cre重组酶基因在雌性小鼠体内的表达 钙/钙调蛋白依赖的蛋白激酶IIα(CaMKIIa)启动子的调控。这是它的后代 在CaMKIIa阳性神经元中缺乏APC的Cross被称为APC条件性敲除(APC CKO)。 APC CKO动物已被证明增加了兴奋性突触交流和增加了 海马区CA1区锥体神经元兴奋性棘细胞密度。APC是一种主要的抑制调节剂。 大的信号通路称为β-连环蛋白/Wnt通路。Apc是β-连环蛋白破坏的一部分 复杂，以β-连环蛋白为靶点进行降解。当APC丢失时，β-连环蛋白水平升高，1)增加 转录一个大的基因家族，以及2)增加兴奋性突触的稳定性。我们是这样开始的 检查APC CKO动物的表型是否与人类一致。我们发现他们展示了 自发的行为痉挛在出生后8-11天，他们有一个发作期的脑电与痉挛行为相关 与人类在IS中的发作活动相似，成年后，它们有自发的脑电和行为 癫痫发作。有趣的是，人类的APC杂合突变与发育和癫痫有关 精神错乱。此外，许多与IS相关的基因要么是β-连环蛋白/Wnt途径的一部分，要么是 受它的相互制约。在这项建议中，我们将具体研究β-连环蛋白在 婴儿痉挛的病理生理学。我们将研究增加β-连环蛋白的影响(通过删除APC和 独立于APC)对痉挛行为、癫痫发作和脑电活动的影响。接下来，我们将表演 操作β-连环蛋白的仔细药代动力学、药效学和不良反应分析 开发一种名为G007-LK的药物。最后，我们将确定是否将β-连环蛋白水平恢复到正常 减轻晚年的痉挛和癫痫发作。这项提案将解决β-连环蛋白在 痉挛的病理生理学，为临床前分析提供了一种新的小鼠模型，并介绍了一大套 治疗IS的新的潜在治疗靶点。

Project summary Infantile spasms (IS, also known as West Syndrome) is a catastrophic childhood epilepsy syndrome characterized by spasms which progress into seizures later in life. Spasms are typified by spontaneous flexion/extension of the head, neck, and limbs and occur first between 4 and 8 months of age. The current treatment options for IS are often ineffective and are associated with significant side effects. Therefore, novel treatment strategies are essential. One limiting factor in identifying new treatment approaches is a paucity of pre-clinical animal models. We have identified and characterized a novel rodent model with many phenotypic characteristics of human IS. The model was generated by breeding male mice containing a floxed version of the Adenomatous polyposis coli (APC) gene with female mice expressing the Cre-recombinase gene under the control of the Ca2+/calmodulin-dependent protein kinase II alpha (CaMKIIa) promoter. The offspring of this cross, which lack APC in CaMKIIa-positive neurons, are known as APC conditional knockouts (APC cKOs). APC cKO animals have been shown to have increased excitatory synaptic communication and an increased density of excitatory spines on hippocampal CA1 pyramidal neurons. APC is the main inhibitory regulator of a large signaling pathway known as the β-catenin/Wnt pathway. APC is part of the β-catenin destruction complex, targeting β-catenin for degradation. When APC is lost, β-catenin levels rise and 1) increase transcription of a large family of genes, and 2) increase the stability of excitatory synapses. We began by examining APC cKO animals for phenotypes consistent with human IS. We found that they exhibit spontaneous behavioral spasms at postnatal days 8-11, they have an ictal EEG correlate of spasm behavior similar to human ictal activity in IS, and as adults, they have spontaneous electrographic and behavioral seizures. Interestingly, APC heterozygous mutations in humans are linked to both developmental and seizure disorders. Furthermore, many of the genes linked to IS are either part of the β-catenin/Wnt pathway or are reciprocally regulated by it. In this proposal, we will specifically examine the role of β-catenin in the pathophysiology of infantile spasms. We will examine the effects of increasing β-catenin (by deleting APC and independently of APC) on spasm behavior, seizures, and electrographic brain activity. Next, we will perform careful pharmacokinetic, pharmacodynamic, and adverse effect analysis of manipulating β-catenin during development with a drug called G007-LK. Lastly, we will determine if restoring β-catenin levels to normal attenuates spasms and seizures later in life. This proposal will address the role of β-catenin in the pathophysiology of spasms, provide a new mouse model for pre-clinical analysis, and introduce a large set of new potential therapeutic targets for the treatment of IS.