Transcriptomic and Proteomic Analysis of Tau-dependent E/I Imbalance

摘要 在不同的大脑疾病中发现了神经网络兴奋/抑制(E/I)失衡的证据 普遍的、破坏性的、对包括阿尔茨海默氏症在内的现有治疗方法无效或反应不佳的 疾病(AD)、癫痫和自闭症谱系障碍。在这些情况下的动物模型中，总体上减少了 非聚集、内源性、野生型tau水平可预防或减少由 多种原因，从淀粉样蛋白的神经堆积到编码钠的基因突变 或钾通道，中风，以及神经递质受体的药物阻断。因为所有的 这些异常会促进E/I失衡和网络过度兴奋，从而扰乱重要的过程 对于神经元和其他脑细胞的健康是必需的，我们假设tau缺乏的人E/I比率降低 大脑至少在很大程度上解释了总体tau减少的广泛治疗益处。在这里，我们建议 通过结合细胞类型特异性tau消融和化学方法来探索潜在的分子机制 诱导E/I失衡的分子图谱分析主要集中在兴奋性前脑神经元。上一首 研究表明，tau可以与过多的其他蛋白质结合或相互作用。因为很多人，如果不是 大多数这些tau相互作用的蛋白都有可能影响神经元的活动，这是主要的机制。 Tau的启动和tau的减少通过什么来抵消网络的超兴奋性仍有待确定。在灯光下 我们最近发现选择性消融兴奋性但不是抑制性神经元中的tau足以 抵消E/I失衡，我们假设这些机制可以通过比较分子 在化学诱导出现之前和期间表达或不表达tau的兴奋性神经元的分布 网络过度兴奋。我们建议在信使核糖核酸水平(目标1)和蛋白质水平检验这一假说。 (目标2)。由于这些方法的优势和劣势互补，以及我们的相关 在实验设计中，我们进一步假设对结果数据集的综合分析(目标3)具有 最好的机会来找出tau启动和tau减少的最关键的机制 病理条件下E/I失衡的发展。识别这些机制可以提供 对tau的病理生物学的新见解，有助于指导tau靶向的发展和评估 治疗，并导致确定更多的适应症和药物靶点。

SUMMARY Evidence for excitation/inhibition (E/I) imbalance of neural networks has been found in diverse brain disorders that are prevalent, devastating, and refractory or poorly responsive to available therapies, including Alzheimer’s disease (AD), epilepsy, and autism spectrum disorders. In animal models for these conditions, reducing overall levels of non-aggregated, endogenous, wildtype tau prevents or diminishes disease manifestations triggered by diverse causes, ranging from the neural accumulation of amyloid proteins to mutations in genes encoding sodium or potassium channels, stroke, and the pharmacological blockade of neurotransmitter receptors. Since all of these abnormalities promote E/I imbalance and network hyperexcitability, which can disrupt important processes required for the health of neurons and other brain cells, we hypothesize that the reduced E/I ratio in tau-deficient brains explains, at least in good part, the broad therapeutic benefits of overall tau reduction. Here, we propose to explore the underlying molecular mechanisms by combining cell type-specific tau ablation and chemically induced E/I imbalance with molecular profiling analyses focused on excitatory forebrain neurons. Previous studies have revealed that tau can bind to or interact with a plethora of other proteins. Because many, if not most, of these tau-interacting proteins have the potential to affect neuronal activities, the primary mechanisms by which tau enables and tau reduction counteracts network hyperexcitability remain to be determined. In light of our recent discovery that selective ablation of tau in excitatory, but not inhibitory, neurons is sufficient to counteract E/I imbalance, we hypothesize that these mechanisms can be revealed by comparing the molecular profile of excitatory neurons that do or do not express tau before and during the emergence of chemically induced network hyperexcitability. We propose to test this hypothesis at the mRNA level (Aim 1) and at the protein level (Aim 2). Because of complementary strengths and weaknesses of these approaches and our related experimental designs, we further hypothesize that an integrative analysis of the resulting datasets (Aim 3) has the best chance to pinpoint the most critical mechanisms by which tau enables and tau reduction counteracts the development of E/I imbalance under pathological conditions. Identifying these mechanisms could provide new insights into the pathobiology of tau, help guide the development and evaluation of tau-targeting therapeutics, and result in the identification of additional indications and drug targets.