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 指出了一些共同的基因在自闭症和精神分裂症中都发生了突变。其中最 这两种疾病的突出单基因是SHANK3，它编码一种突触支架蛋白。 然而，Shank3突变如何不同地影响突触功能的机制仍然不清楚。一个 最近在上皮细胞中的研究表明，SHANK2与分割-缺陷(PAR)极性复合体相互作用， 它包括PAR3、PAR6和非典型PKC(APKC)。与此一致，我们的初步数据显示， 在体内，SHANK3与一个PKC相互作用，这种相互作用在Par3条件基因敲除中被减少 海马体。有趣的是，我们发现在与Shank3 ASD相关的InsG3680中，aPKC的激活减少 突变的小鼠大脑，而在与Shank3精神分裂症相关的Shank3中观察到aPKC的过度激活 R1117X突变脑。因此，我们假设Shank3将PAR极性复合体定位于突触 并调节其激活。ASD和精神分裂症相关的Shank3突变将导致 不同的aPKC激活失调，导致突触可塑性和 行为缺陷。在第一个目标中，我们将检验树突棘突结构可塑性是 受Shank3、ASD和精神分裂症突变体的不同影响通过aPKC的异常激活。在……里面 目的2，我们将检验一个假设，即在Shank3突变体中，aPKC激活的失调导致改变 AMPA受体(AMPAR)在脊柱表面的运输和纳米结构域的定位。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，结合双光子谷氨酸去老化诱导树突棘结构可塑性。我们会 此外，在SHANK3 ASD和精神分裂症中，也可以用生化分析来补充这些成像方法- 相关突变敲击小鼠模型。总之，我们提议的研究将建立一种机械联系 Shank3和PAR极性复合体在神经发育障碍突触可塑性调节中的作用 包括自闭症和精神分裂症。因为Par3基因与自闭症、精神分裂症和高认知能力有关 表现，我们的研究将阐明Shank3-PAR极性信号复合体在认知中的作用 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.