The Epileptogenic Effect of Perinatal Hypoxia

与缺氧性脑病相关的新生儿癫痫发作难治 传统的AED治疗，与长期的神经发育有关 延迟、认知障碍和癫痫。新生儿的大脑从根本上说是不同的 来自成人大脑，并且作为以下函数对癫痫刺激特别敏感 活性依赖性突触发生所需的生理性超兴奋性和 皮质发育。在过去的15年里，这项研究计划产生了 可靠的新生儿缺氧性惊厥的啮齿动物模型，确定特定的年龄相关性 机制，验证了这些靶标在人类新生儿中的年龄特异性表达 皮质组织，并在大鼠身上进行针对这些组织的治疗试验 机制，使用临床上可用的药物。在我们新生儿癫痫的啮齿动物模型中， 我们已经证明，全身性给予谷氨酸受体拮抗剂48小时 癫痫发作后可以防止长期后果，因此可能是疾病 正在修改。目前的提议将侧重于这一立即和早期的扣押 识别现有蛋白质和调控蛋白的快速翻译后修饰的窗口 控制蛋白质从预先存在的mRNA翻译的机制可能是 可预防和/或可逆。 目的1.测定癫痫发作后离子亲性谷氨酸变化的时程 受体功能，以及它们是否与翻译后修饰有关 受体亚基。 目的2.确定AMPAR和NMDAR中的翻译后修饰 仅与缺氧性惊厥相关或机械相关 体内和体外的癫痫发生。 目的3.确定雷帕霉素(MTOR)信号的哺乳动物靶点 通路是预防缺氧性惊厥的治疗靶点 过度兴奋。 目的4.继续我们的人体组织对谷氨酸成熟模式的研究 受体的表达，并研究是否可以检测到mTOR通路的激活 在缺氧足月婴儿的死后人脑组织中。 我们的初步结果显示，许多这些早期癫痫发作引起的变化 蛋白质与突触可塑性模型中观察到的蛋白质惊人地相似。这个 这一提议的总体假设是，这些早期的变化代表着干预 抗癫痫积分，即使在癫痫发作诱导后也是如此。一位少校 此资助期的重点是在这48小时窗口中确定这些分子靶点 并用已知具有调节作用的现成药物进行干预 这些目标的活动。项目叙述和卫生相关性 与缺氧性脑病相关的新生儿癫痫发作对传统的AED治疗是困难的， 与长期神经发育迟缓、认知障碍和癫痫有关。新生儿 大脑从根本上不同于成人的大脑，作为一种 活动依赖性突触发生和皮层所需的生理性高兴奋性的功能 发展。在过去的15年里，这项研究计划(NS31718)已经产生了一个可靠的模型 新生儿缺氧性癫痫，确定特定的年龄依赖机制，验证特定的年龄 这些靶点在人新生儿皮质组织中的表达，并在大鼠身上进行治疗试验 针对这些机制，使用临床上可用的药物。通过直接和合作的努力， 这项研究计划对于提出仅有的两种被考虑用于第一种疗法的药物至关重要。 新生儿癫痫治疗试验网络(NESTT)在过去40多年中对新生儿癫痫的试验。 这两种药物是托吡酯(TPM)，我们已经向靶点展示了在 以及布美他尼，我们已经证明是一种特定的氯离子转运体NKCC1的阻断剂 在新生儿大脑中过度表达，导致GABA激动剂缺乏疗效 (巴比妥类、苯二氮卓类)。值得注意的是，AMPAR拮抗剂，包括TPM，是有效的 在最初的癫痫发作后给药，以防止长期后果，因此这可能是 FDA批准的第一种抑制新生儿癫痫发生的药物。目前的建议旨在完善我们的 了解这一新的抗癫痫作用，并潜在地阐明其他可用于 对这一独特人群的治疗干预。

Neonatal seizures associated with hypoxic encephalopathy are refractory to conventional AED therapy, and are associated with long term neurodevelopmental delay, cognitive impairment and epilepsy. The newborn brain is fundamentally different from the adult brain, and is uniquely susceptible to epileptic stimuli as a function of physiological hyperexcitability required for activity dependent synaptogenesis and cortical development. In the prior 15 years, this research program has generated a reliable rodent model of neonatal hypoxic seizures, identified specific age-dependent mechanisms, validated the age specific expression of these targets in human neonatal cortical tissue, and executed therapeutic trials in the rat targeted towards these mechanisms, using clinically available drugs. In our rodent models of neonatal seizures, we have shown that systemic administration of glutamate receptor antagonists for 48 hrs following seizures can prevent the long term consequences, and hence may be disease modifying. The present proposal will focus on this immediate and early post seizure window to identify rapid post-translational modifications of existing protein and regulatory mechanisms governing the translation of protein from of pre-existing mRNA that may be preventable and/or reversible. Aim 1. To determine the time course of seizure-induced changes in ionotropic glutamate receptor function, and whether they are associated with post-translational modification of receptor subunits. Aim 2. To establish whether post-translational modifications in AMPARs and NMDARs are merely correlated or mechanistically related to in hypoxic seizure-induced epileptogenesis in vivo and in vitro. Aim 3. To determine whether the mammalian target of rapamycin (mTOR) signaling pathway represents a therapeutic target for prevention of hypoxic-seizure induced hyperexcitability. Aim 4. To continue our human tissue study of maturational patterns of glutamate receptor expression and investigate whether mTOR pathway activation can be detected in postmortem human brain tissue from hypoxic term infants. Our preliminary results reveal that many of these early seizure induced changes in proteins are strikingly similar to those observed in models of synaptic plasticity. The overall hypothesis of this proposal is that these early changes represent intervention points for antiepileptogenesis, even after the seizures have been induced. A major focus for this funding period is to identify these molecular targets in this 48 hr window and intervene with available off-the-shelf drugs that are known to have modulatory activity at these targets. Project narrative and health relevance Neonatal seizures associated with hypoxic encephalopathy are refractory to conventional AED therapy, and are associated with long term neurodevelopmental delay, cognitive impairment and epilepsy. The newborn brain is fundamentally different from the adult brain, and is uniquely susceptible to epileptic stimuli as a function of physiological hyperexcitability required for activity dependent synaptogenesis and cortical development. In the prior 15 years, this research program (NS31718) has generated a reliable model of neonatal hypoxic seizures, identified specific age-dependent mechanisms, validated the age specific expression of these targets in human neonatal cortical tissue, and executed therapeutic trials in the rat targeted towards these mechanisms, using clinically available drugs. Through direct and collaborative efforts, this research program has been critical to proposing the only 2 agents being considered for the first therapeutic trials by the Neonatal Seizure Treatment Trial Network (NESTT) for neonatal seizures in the last 4+ decades. The 2 agents are topiramate (TPM), which we have shown targets the AMPARs that are overexpressed in the immature brain, and bumetanide, a blocker of a specific Cl- transporter NKCC1 that we have shown to be overexpressed in the newborn brain and which contributes to the lack of efficacy of GABA agonists (barbiturates, benzodiazepines) in this population. Notably AMPAR antagonists, including TPM, are effective at preventing long term consequences when administered after the initial seizures, and hence this may be the first FDA-approved agent to inhibit epileptogenesis in neonates. The present proposal aims to refine our understanding of this novel antiepileptogenic effect, and potentially elucidate other targets that can be used for therapeutic intervention in this unique population.