TSC-mTOR on neuron development

描述（由申请方提供）：本提案将检验以下假设：直接mTOR效应物和下游以及mTOR非依赖性分子导致皮质神经元肥大和多发性硬化症（TSC）中的错位。该提案的长期目标是预防或挽救TSC中的脑畸形和涉及PI 3 K通路的其他疾病。TSC是由TSC 1或TSC 2的突变引起的，导致mTOR活动过度和与癫痫发作以及认知和精神缺陷恶化相关的发育畸形。mTOR抑制剂雷帕霉素是唯一的治疗选择，不能挽救所有缺陷，并且具有主要的副作用，强调需要更好地了解TSC的分子基础并找到新的药物靶点。我们和其他人已经开发了TSC相关皮质病变的小鼠模型。在这些模型中发现的一致缺陷是神经元错位和树突肥大。脊柱缺陷仍不清楚。在这里，我们建议确定一些负责异常的位置和形态发生（树突和棘）的皮质锥体神经元的分子球员。mTOR直接磷酸化翻译阻遏物eIF 4 E结合蛋白（4 E-BP）和p70核糖体S6蛋白激酶1（S6 K1）。在目的1中，我们将确定4 E-BP和/或S6 K1是否介导mTOR对皮层神经元发育的影响。典型的mTOR激活剂Rheb被TSC 1/TSC 2复合物抑制，可能导致一些独立于mTOR的缺陷，但这仍然是推测性的。在目标2中，我们提出鉴定哪些mTOR依赖性和非依赖性分子导致TSC中的皮质缺陷。最后，在目标3中，我们将测试鉴定的分子（例如FLNA）是否预防和挽救TSC中的神经元缺陷。我们将与Breunig博士合作，在野生型和转基因小鼠中使用遗传和药理学操作以及翻译核糖体亲和纯化（TRAP）分析的组合。

DESCRIPTION (provided by applicant): This proposal will test the hypothesis that the direct mTOR effectors and downstream as well as mTOR-independent molecules contribute to cortical neuron hypertrophy and misplacement in Tuberous Sclerosis Complex (TSC). The long term goal of this proposal is to prevent or rescue brain malformations in TSC and other disorders involving the PI3K pathway. TSC is caused by mutations in TSC1 or TSC2 leading to mTOR hyperactivity and developmental malformations associated with seizures and worsening of cognitive and psychiatric deficits. The mTOR inhibitor rapamycin is the only therapeutic option, does not rescue all defects, and has major side-effects emphasizing the need to better understand the molecular basis of TSC and find novel drug targets. We and others have developed mouse models of TSC-associated cortical lesions. Consistent defects found across these models are neuronal misplacement and dendrite hypertrophy. Spine defects remain unclear. Here, we propose to identify some of the molecular players responsible for abnormal placement and morphogenesis (dendrites and spines) of cortical pyramidal neurons. mTOR directly phosphorylates the translational repressor eIF4E binding protein (4E-BP) and p70 ribosomal S6 protein kinase 1 (S6K1). In Aim 1, we will determine whether 4E-BP and/or S6K1 mediate mTOR effects on cortical neuron development. The canonical mTOR activator, Rheb, which is inhibited by the TSC1/TSC2 complex may contribute to some defects independently of mTOR, but this remains speculative. In aim 2, we propose to identify which mTOR- dependent and -independent molecules contribute to cortical defects in TSC. Finally, in aim 3 we will test whether identified molecules (e.g. FLNA) prevent and rescue neuronal defects in TSC. We will use a combination of genetic and pharmacological manipulations as well as translating ribosome affinity purification (TRAP) analysis in collaboration with Dr. Breunig in wild-type and transgenic mice.