Targeting Postsynaptic Small G-protein Regulators

摘要 本申请旨在发现和验证Rac鸟苷核苷酸的小分子抑制剂 交换因子（GEF）卡林，在大脑皮层的树突棘的主要信号转导枢纽。 我们的长期目标是将有关树突棘可塑性和突触小GTdR的知识 信号传导，用于治疗神经精神疾病（NPD）。树突棘是大多数 大脑中的兴奋性突触，并在神经元回路的发育和可塑性中发挥核心作用， 最终影响到学习记忆和行为相反，树突棘的异常 广泛参与NPD发病机制。由小GTP酶如Rac介导的分子途径， 直接上游激活因子（GEF）及其下游靶点是调控树突状细胞的主要途径， 脊柱可塑性此外，遗传和尸检研究表明这些途径发挥着关键作用 在NPD发病机制中的作用。Kalirin是大脑皮层中树突棘中最丰富的Rac-GEF 和海马，在脊柱可塑性和病理学中起着中心作用，如敲除和 基因敲除研究，并已牵连在NPD的遗传，死后，和功能的研究。因此，我们认为， 为了研究kalirin在皮质可塑性和NPD发病机制中的作用，以及Rac-GT3信号转导， 一般来说，我们的目标是开发新的、有效的、特异性的、具有生物活性的卡林抑制剂， 神经元我们已经建立了突触生物学和NPD专家之间的合作，高- 通量筛选和计算药理学、药物化学和晶体学，以及 进行了广泛的初步研究，证明了我们的假设的有效性和可行性 我们的方法。我们提出了以下具体目标：1）通过HTS发现命中，以识别小的 结合卡林的DHPH结构域并抑制其GEF活性的分子。2)蜂窝中的命中验证 和神经元测定。3)命中化合物作用机制的表征。4)药用 新型GEF缓蚀剂的化学优化

ABSTRACT This application aims to discover and validate small-molecule inhibitors of the Rac guanosine-nucleotide exchange factor (GEF) kalirin, a major signal transduction hub in dendritic spines in the cerebral cortex. Our long-term goal is to translate knowledge about dendritic spine plasticity and synaptic small GTPase signaling, into treatments of neuropsychiatric disorders (NPDs). Dendritic spines are the sites of most excitatory synapses in the brain, and play central roles in the development and plasticity of neuronal circuits, and ultimately in learning, memory, and behavior. Conversely, abnormalities in dendritic spines are extensively involved in NPD pathogenesis. Molecular pathways mediated by small GTPases such as Rac, direct upstream activators (GEFs), and their downstream targets are major pathways that govern dendritic spine plasticity. Furthermore, genetic and postmortem studies demonstrate a key role for these pathways in the pathogenesis of NPDs. Kalirin is the most abundant Rac-GEF in dendritic spines in the cerebral cortex and hippocampus, plays central roles in spine plasticity and pathology as shown by knockdown and knockout studies, and has been implicated in NPDs by genetic, postmortem, and functional studies. Hence, in order to study the role of kalirin in cortical plasticity and NPD pathogenesis, and of Rac-GTPase signaling in general, here we aim to develop novel, potent, specific, inhibitors of kalirin with biological activity in neurons. We have established a collaboration between experts in synapse biology and NPDs, high- throughput screening and computational pharmacology, medicinal chemistry, and crystallography, and performed extensive preliminary studies that demonstrate the validity of our hypothesis and the feasibility of our approach. We propose the following Specific Aims: 1) Hit discovery by HTS to identify small molecules binding to kalirin's DHPH domain and inhibiting its GEF activity. 2) Hit validation in cellular and neuronal assays. 3) Characterization of the mechanism of action of hit compounds. 4) Medicinal chemistry optimization of new GEF inhibitors