Synaptic Protein Networks, Genetic Risk, and Spine Loss in Schizophrenia

摘要 精神分裂症(Sz)是一种终生的破坏性精神疾病，治疗选择有限，无法治愈。 精神分裂症患者多个脑区反复观察到第3层锥体细胞树突棘丢失 (SZ)，包括初级听觉皮质(AI)。脊椎缺失被认为是初级听觉皮质的基础 在Sz观察到的加工缺陷，导致Sz的社会认知受损和幻听。 我们已经证明在Sz Al第三层中只有较小的脊椎丢失。最近的双光子活体成像研究 已经证明，新的脊椎很小，对突触的形成是必不可少的，也是成人新学习所必需的。 动物。突触蛋白网络(SynPN)调控树突棘的形成、稳定和可塑性 特征，如蛋白质表达、运输和磷酸化(PHO)，以及相当数量的Sz风险 突触蛋白的基因座编码。 靶向和散弹枪质谱(MS)方法发现突触体和PHO发生了强烈的变化 深圳地区典型突触后蛋白的水平。这些变化不能用相应的变化来解释 在这些蛋白质的匀浆水平上，表明Sz中SynPN病理的首当其冲是由 蛋白质表达以外的过程(例如蛋白质的运输和活性)。八种蛋白质上的九个磷酸酶位点 与突触体蛋白水平和小脊柱密度高度相关。除了这8个人中的一个之外，所有的人 蛋白质在突触后谷氨酸受体和脊椎的囊泡运输中的作用已得到充分证实 监管。突触后谷氨酸信号转导通路是最重要的遗传信号通路之一。 关于Sz.的研究因此，我们假设：突触后蛋白的异常运输与PHO有关。 增加Sz的遗传风险，并导致Sz Al的小范围脊椎丧失。 我们将在一组史无前例的平行基因组、蛋白质组和显微镜下测试这一假设。 在100名Sz和100名匹配的对照组受试者中进行的实验，使用尖端计算分析来识别 与Sz遗传学有关的蛋白质和磷酸根化合物，并产生疾病的因果模型(目标1)。然后我们将利用 创新的分子和双光子显微镜方法来测试候选PHO的效果，来自我们的 初步研究和高度优先的目标1发现，在Al的脊柱密度，大小，形成和稳定性 成年小鼠(目标2)。 这些研究将确定可能与Sz风险遗传学相关的近端分子事件，这些事件可能会损害 Sz Al中的小脊椎，以及脊柱形成/稳定阶段受损。这类事件可能是 在未来的研究中通过CRISPR/Cas9在体内进一步研究，并有可能成为 开发新的治疗方法。

Abstract Schizophrenia (Sz) is a lifelong and devastating psychiatric illness with limited treatment options and no cure. Layer 3 pyramidal cell dendritic spine loss has been repeatedly observed in multiple brain areas in schizophrenia (Sz), including the primary auditory cortex (AI). Spine loss is postulated to underlie primary auditory cortex processing deficits observed in Sz, contributing to impaired social cognition and auditory hallucinations in Sz. We have shown that only smaller spines are lost in Sz Al layer 3. Recent two-photon in vivo imaging studies have shown that new spines are small, essential for synaptogenesis, and required for new learning in adult animals. Dendritic spine formation, stabilization, and plasticity are regulated by synaptic protein network (SynPN) features, such as protein expression, trafficking, and phosphorylation (Phos), and a significant number of Sz risk loci code for synaptic proteins. Targeted and shotgun mass spectrometry (MS) approaches found robust changes in synaptosome and Phos levels of canonical postsynaptic proteins in Sz. These changes were not explained by corresponding changes in homogenate levels of these proteins, suggesting that the brunt of SynPN pathology in Sz is regulated by processes beyond protein expression (e.g. protein trafficking and activity). Nine Phos sites on eight proteins were highly correlated with both synaptosome protein levels and small spine density. All but one of these 8 proteins have well documented roles in vesicular trafficking of postsynaptic glutamate receptors and spine regulation. Postsynaptic glutamate signaling is one of the most significantly implicated pathways in genetic studies of Sz. Thus, we hypothesize that: Aberrant trafficking and Phos of postsynaptic proteins is linked to Sz genetic risk and drives small spine loss in Sz Al. We will test this hypothesis in an unprecedented set of parallel genomic, proteomic, and microscopy experiments in 100 Sz and 100 matched control subjects with cutting edge computational analyses to identify protein and Phos linked to Sz genetics and generate causal models of disease (Aim 1). We will then utilize innovative molecular and two-photon microscopy approaches to test the effects of candidate Phos, from our preliminary studies and high priority Aim 1 findings, on spine density, size, formation, and stability in the Al of adult mice (Aim 2). These studies will identify proximal molecular events, potentially associated with Sz risk genetics, that impair small spines in Sz Al, as well as the stage of spine formation/stabilization that is impaired. Such events can be further investigated in vivo via CRISPR/Cas9 in future studies and have the potential to serve as targets for the development of novel therapeutics.