Optical monitoring of the role of neurogenesis in epileptogenesis

癫痫是一种毁灭性的神经系统疾病，仅在美国就有300多万成年人受到影响。最常见的癫痫形式是颞叶癫痫（TLE）。TLE的特征是最初发作或损伤，随后是潜伏期，在此期间疾病症状被隐藏。然后发展为慢性和反复发作，通常从海马体开始，并传播到整个大脑。30%的TLE病例产生耐药性，并导致癫痫发作、情绪障碍、记忆丧失、严重损伤和猝死风险增加等慢性痛苦。因此，这项工作的长期目标是开发以异常海马活动为特征的神经系统疾病的新疗法。了解TLE如何在大脑中发展对医学界来说是一个复杂的挑战，因为它可以在脑损伤或最初癫痫发作后的几天到几年内随时发展，对一些患者来说，它根本不会发展。在癫痫患者的大脑中，海马体过度活跃。然而，尚不清楚海马体在初始事件后如何转变为这种状态，以及这一过程中的可变性是否解释了为什么有些患者会发展为TLE，而另一些患者则不会。先前对小鼠的研究表明，这种高兴奋性发生在海马的齿状回（DG）亚区，这种现象与成人神经发生的过程有关。成年神经发生是健康DG的一个标志性特征，成年出生的颗粒细胞（abGCs）不断整合到现有的回路中，并与成熟细胞形成连接。随着TLE的发展，神经发生过程被破坏。因此，在初始损伤时间附近出生的abGCs通常表现出发育异常，不能正确地整合到DG电路中。这些变化使他们能够放大海马体中的癫痫活动。因此，这项提议的总体目标是通过保护abGCs不发展促进癫痫发作的特征和连接来预防小鼠的慢性癫痫发作。具体目标旨在了解和预防TLE小鼠模型体内回路水平的变化，并将在专家指导团队的指导下进行。目的1将使用非线性显微镜记录成熟和成年出生的DG神经元在匹罗卡品诱发癫痫的整个过程中的脑活动。我们期望发现由abGCs病理成熟引起的这些电路动力学的变化，将预测慢性癫痫发作的严重程度和频率。目的2还将使用非线性显微镜来比较不同治疗干预措施在预防慢性癫痫发作方面的疗效。假设这些干预措施可以抵消过度兴奋性并保护abGCs不发展为病理特征。这项工作将提供第一个预测慢性癫痫发作的策略，并将比较预防性干预措施的效果。因此，这些独立但互补的目标将为开发下一代治疗策略提供关键见解，以完全预防TLE。这项工作将伴随着量身定制的专业发展计划，以确保这项工作的长期目标以高度的科学严谨性执行。

Epilepsy is a devastating neurological condition that affects over 3 million adults in the U.S. alone. The most common form of epilepsy is temporal lobe epilepsy (TLE). TLE is characterized by an initial seizure or injury, followed by a latent period, during which the disease symptoms are hidden. It then progresses to chronic and recurrent seizures that often begin in the hippocampus and propagate throughout the brain. 30% of TLE cases become drug-resistant and cause chronic suffering from seizures, mood disorders, memory loss, severe injury, and increased risk of sudden death. Accordingly, the long-term goal of this work is to develop new treatments for neurological disorders characterized by abnormal hippocampal activity. Understanding how TLE develops in the brain poses a complex challenge to the medical community because it can develop anytime in the days to years that follow the brain injury or initial seizure, and for some patients, it does not develop at all. In the epileptic brain, the hippocampus is hyperactive. However, it is unclear how the hippocampus converts to this state after the initial event, and if variability in this process explains why some patients develop TLE, while others do not. Previous studies in mice suggest that the hyperexcitability accrues in the dentate gyrus (DG) subregion of hippocampus, and that this phenomenon is related to a process called adult neurogenesis. Adult neurogenesis is a hallmark feature of the healthy DG, whereby adult-born granule cells (abGCs) continuously integrate into the existing circuit and form connections with mature cells. As TLE develops, the process of neurogenesis is disrupted. As a result, abGCs born near the time of the initial injury often show developmental abnormalities and do not integrate properly into the DG circuit. These changes enable them to amplify seizure activity in the hippocampus. Therefore, the overall objective of this proposal is to prevent chronic seizures in mice by protecting abGCs from developing features and connections that promote seizures. The specific aims are designed to understand and prevent circuit-level changes in vivo in a mouse model of TLE and will be conducted under the guidance of an expert mentoring team. Aim 1 will use nonlinear microscopy to record the brain activity of mature and adult-born DG neurons throughout the progression of pilocarpine-induced epilepsy. We expect to find that changes to these circuit dynamics, caused by pathological maturation of abGCs, will predict the severity and frequency of chronic seizures. Aim 2 will also use nonlinear microscopy to compare the efficacy of different therapeutic interventions in preventing chronic seizures from developing. These interventions are hypothesized to counteract hyperexcitability and protect abGCs from developing pathological features. This work will provide the first strategy to predict chronic seizures and will compare the efficacy of preventive interventions. Therefore, these independent yet complementary aims will provide critical insight for developing next-generation therapeutic strategies to prevent TLE altogether. This work will be accompanied by a tailored plan for professional development to ensure the long-term goals of this work are executed with a high degree of scientific rigor.