Data_Sheet_1_Genes Bound by ΔFosB in Different Conditions With Recurrent Seizures Regulate Similar Neuronal Functions.XLSX

Seizure incidence is increased in Alzheimer’s disease (AD) patients and mouse models, and treatment with the antiseizure drug levetiracetam improves cognition. We reported that one mechanism by which seizures can exert persistent effects on cognition is through accumulation of ΔFosB, a transcription factor with a long half-life. Even the infrequent seizures that spontaneously occur in transgenic mice expressing human amyloid precursor protein (APP) lead to persistent increases in ΔFosB in the hippocampus, similar to what we observed in patients with AD or temporal lobe epilepsy. ΔFosB epigenetically regulates expression of target genes, however, whether ΔFosB targets the same genes when induced by seizures in different neurological conditions is not clear. We performed ChIP-sequencing to assess the repertoire of ΔFosB target genes in APP mice and in pilocarpine-treated wildtype mice (Pilo mice), a pharmacological model of epilepsy. These mouse models allowed us to compare AD, in which seizures occur in the context of high levels of amyloid beta, and epilepsy, in which recurrent seizures occur without AD-specific pathophysiology. Network profiling of genes bound by ΔFosB in APP mice, Pilo mice, and respective control mice revealed that functional domains modulated by ΔFosB in the hippocampus are expanded and diversified in APP and Pilo mice (vs. respective controls). Domains of interest in both disease contexts involved neuronal excitability and neurotransmission, neurogenesis, chromatin remodeling, and cellular stress and neuroinflammation. To assess the gene targets bound by ΔFosB regardless of seizure etiology, we focused on 442 genes with significant ΔFosB binding in both APP and Pilo mice (vs. respective controls). Functional analyses identified pathways that regulate membrane potential, glutamatergic signaling, calcium homeostasis, complement activation, neuron-glia population maintenance, and chromatin dynamics. RNA-sequencing and qPCR measurements in independent mice detected altered expression of several ΔFosB targets shared in APP and Pilo mice. Our findings indicate that seizure-induced ΔFosB can bind genes in patterns that depend on seizure etiology, but can bind other genes regardless of seizure etiology. Understanding the factors that underlie these differences, such as chromatin accessibility and/or abundance of co-factors, could reveal novel insights into the control of gene expression in disorders with recurrent seizures.

在阿尔茨海默病（AD）患者及小鼠模型中，癫痫发作的发生率有所上升，而使用抗癫痫药物拉莫三嗪治疗可改善认知功能。本研究报告了一种机制，即癫痫发作可通过累积半衰期较长的转录因子ΔFosB对认知产生持久影响。即便是那些在表达人源淀粉样前体蛋白（APP）的转基因小鼠中自发发生的罕见癫痫发作，也会导致海马区ΔFosB的持续增加，这与我们在阿尔茨海默病或颞叶癫痫患者身上观察到的现象相似。ΔFosB通过表观遗传调控目标基因的表达，然而，当在不同神经系统疾病中由癫痫发作诱导时，ΔFosB是否靶向相同的基因尚不明确。我们通过ChIP-sequencing技术评估了APP小鼠和经匹罗卡品处理的野生型小鼠（Pilo小鼠，癫痫的药理模型）中ΔFosB目标基因库。这些小鼠模型使我们能够比较阿尔茨海默病（其中癫痫发作发生在高水平的β-淀粉样蛋白背景下）和癫痫（其中反复发生的癫痫发作无AD特异性病理生理学），并揭示了由ΔFosB调控的海马区功能域在APP和Pilo小鼠中相对于各自对照组而言得到了扩展和多样化。在两种疾病背景下，感兴趣的领域均涉及神经元兴奋性、神经递质传递、神经发生、染色质重塑以及细胞应激和神经炎症。为了评估无论癫痫病因如何，ΔFosB结合的基因靶点，我们聚焦于在APP和Pilo小鼠中（相对于各自对照组）具有显著ΔFosB结合的442个基因。功能分析确定了调节膜电位、谷氨酸能信号传导、钙稳态、补体激活、神经元-胶质细胞群维持和染色质动态的通路。在独立小鼠中进行的RNA测序和qPCR测量检测到在APP和Pilo小鼠中共享的几个ΔFosB靶基因表达发生改变。我们的研究结果表明，癫痫诱导的ΔFosB可以以依赖于癫痫病因的模式结合基因，但也可以结合其他基因而不论癫痫病因。了解导致这些差异的因素，例如染色质可及性和/或共因子的丰度，可能揭示关于控制具有反复发作的疾病中基因表达的全新见解。