Shank3 and the Par polarity complex in neurodevelopmental disorders

项目摘要 自闭症谱系障碍（ASD）和精神分裂症是两种不同的神经发育障碍， 某些共同的症状然而，导致这些不同和共享的潜在突触机制 行为表型仍然难以捉摸。这两种疾病都显示出很强的遗传成分，最近的研究表明， 已经指出了一些在自闭症和精神分裂症中突变的共有基因。一个最 这两种疾病的主要单基因是SHANK 3，它编码一种突触支架蛋白。 然而，Shank 3突变差异影响突触功能的机制仍不清楚。一 最近在上皮细胞中的研究显示Shank 2与分配缺陷（Par）极性复合物相互作用， 包括Par 3、Par 6和非典型PKC（aPKC）。与此相一致，我们的初步数据显示， Shank 3在体内与aPKC相互作用，并且这种相互作用在Par 3条件性敲除中减少 海马体。有趣的是，我们发现在Shank 3 ASD相关的InsG 3680中aPKC活化减少， 突变小鼠脑，而在Shank 3精神分裂症相关的 R1117 X变异大脑因此，我们假设Shank 3将Par极性复合物靶向突触 并调节其激活。ASD和精神分裂症相关的Shank 3突变将导致 aPKC激活的差异失调，导致突触可塑性的明显变化， 行为缺陷在第一个目标中，我们将测试树突棘结构可塑性是一个假设， Shank 3 ASD和精神分裂症突变体通过aPKC激活失调而受到不同影响。在 目的2，我们将检验Shank 3突变体中aPKC激活的失调导致蛋白激酶C的改变这一假设。 AMPA受体（AMPAR）运输和纳米结构域定位在脊柱表面。我们的研究将利用 先进的分子成像技术，包括τSTED超分辨率成像，FRET和FRAP活细胞 成像，结合双光子谷氨酸未包裹诱导的树突棘结构可塑性。我们将 也补充了这些成像方法与生化分析在SHANK 3 ASD和精神分裂症- 相关的突变敲入小鼠模型。总之，我们提出的研究将建立一个机械的联系， Shank 3和Par极性复合体在神经发育障碍中调节突触可塑性的作用 包括自闭症和精神分裂症由于Par 3在遗传上与ASD、精神分裂症和高认知障碍有关， 我们的研究将阐明Shank 3-Par极性信号复合体在认知行为中的作用， 神经发育障碍的缺陷。

Project Summary Autism Spectrum Disorders (ASD) and schizophrenia are two distinct neurodevelopmental disorders with certain shared symptoms. Yet the underlying synaptic mechanisms leading to these distinct and shared behavioral phenotypes remain elusive. Both disorders show a strong genetic component, and recent studies have pointed to a number of shared genes that are mutated in both ASD and schizophrenia. One of the most prominent monogenic genes for both disorders is SHANK3, which encodes a synaptic scaffolding protein. However, the mechanisms by which Shank3 mutations differentially affect synaptic functions are still unclear. A recent study in epithelial cells shows Shank2 interacts with the partitioning-defective (Par) polarity complex, which includes Par3, Par6 and atypical PKC (aPKC). Consistent with this, our preliminary data show that Shank3 interacts with aPKC in vivo, and this interaction is reduced in the Par3 conditional knockout hippocampus. Interestingly, we found that aPKC activation is reduced in Shank3 ASD-associated InsG3680 mutant mouse brains, while an overactivation of aPKC is observed in Shank3 schizophrenia-associated R1117X mutant brains. Thus, we hypothesize that Shank3 targets the Par polarity complex to synapses and regulates its activation. ASD- and schizophrenia-associated Shank3 mutations will result in differential dysregulation of aPKC activation, leading to distinct changes in synaptic plasticity and behavioral defects. In the first aim, we will test the hypothesis that dendritic spine structural plasticity is differentially affected by Shank3 ASD and schizophrenia mutants through dysregulated activation of aPKC. In Aim 2, we will test the hypothesis that dysregulation of aPKC activation in Shank3 mutants leads to altered AMPA receptor (AMPAR) trafficking and nanodomain localization at the spine surface. Our studies will utilize advanced molecular imaging techniques, including τSTED super resolution imaging, FRET and FRAP live cell imaging, combined with two-photon glutamate uncaging-induced dendritic spine structural plasticity. We will also complement these imaging approaches with biochemical analyses in SHANK3 ASD and schizophrenia- associated mutant knockin mouse models. Together, our proposed studies will establish a mechanistic link between Shank3 and the Par polarity complex in regulating synaptic plasticity in neurodevelopmental disorders including ASD and schizophrenia. As Par3 is genetically linked to ASD, schizophrenia, and high cognitive performance, our studies will shed light on the role of a Shank3-Par polarity signaling complex in cognitive defects in neurodevelopmental disorders.