Mechanisms regulating KCC2 hypofunction during refractory seizures in a mouse model of ischemic neonatal seizures

项目总结/摘要： 本研究项目的长期目标是了解 新生儿苯巴比妥抵抗性癫痫发作，KCC 2功能减退在难治性癫痫发作中的作用 癫痫发作，以及新型KCC 2功能增强剂在新生儿缺血性脑卒中小鼠模型中的疗效 癫痫发作难治性新生儿癫痫发作与儿童癫痫综合征和认知功能高度相关。 残疾。更有效的治疗方法的开发将受益于对 病理生理学和动物模型中潜在的难治性和癫痫发生的机制。的 KCC 2氯共转运体是中枢神经系统神经元中主要的氯离子输出体。严重损害， a神经元排出Cl-的能力逆转跨膜Cl-梯度，导致GABA介导的 去极化而不是超极化。新生儿大脑中的兴奋性毒性损伤通常与 重度癫痫发作负担，通常对GABA激动剂一线治疗干预无效 比如苯巴比妥我们以前的工作表明缺血显著下调Cl-协同转运体， KCC 2表达，但NKCC 1表达，这是Cl-进口商保持不受影响的趋势， 在缺血后的大脑中上调。挽救KCC 2的病理生理功能减退， 缺血性损伤在新生儿脑中是一种未经测试的策略。假设：挽救KCC 2功能减退， 新生儿缺血将恢复突触抑制和神经元网络活动的生理水平。这 补救措施将防止出现难治性癫痫发作，并成功地减少与GABA的癫痫发作负担 激动剂，这反过来又会在长期内改善疾病。目的：1.绘制早期和急性脑梗死的动态图， 缺血后KCC 2降解，并研究缺血后KCC 2功能低下的调节。 缺血性癫痫2.记录KCC 2降解相关的皮层神经元去极化， 缺血和KCC 2激动剂在体外对这种去极化的影响3.抢救难治性缺血性- 用新型KCC 2激动剂体内癫痫发作和对长期合并症的定量作用。合格品： 成功完成本项目后，我们将进一步了解动态之间的联系， KCC 2在新生儿惊厥发作至出现难治性时表达的变化。影响和 创新：了解不成熟的大脑通过重复的 新生儿期癫痫发作将有助于指导以证据为基础的策略治疗难治性癫痫。 癫痫发作通常与儿童严重的长期合并症有关。

Project summary/abstract: The long-term goal of this research project is to gain an understanding of the broader relationship between phenobarbital-resistant seizures in neonates, the role of KCC2 hypofunction in the emergence of refractory seizures, and the efficacy of novel KCC2 functional enhancers in a mouse model of neonatal ischemic seizures. Refractory neonatal seizures are highly correlated with childhood seizure syndromes and cognitive disabilities. The development of more effective therapies will benefit from a deeper understanding of the pathophysiology and mechanisms of underlying refractoriness and epileptogenesis in animal models. The KCC2 chloride co-transporter is the chief Cl- extruder in central nervous system neurons. Severe impairment in a neurons ability to extrude Cl- reverses the transmembrane Cl- gradient resulting in GABA mediated depolarization instead of hyperpolarization. Excitotoxic insults in neonatal brains are often associated with severe seizure burdens that are commonly refractory to first-line therapeutic interventions with GABA agonists like phenobarbital. Our previous work has shown that ischemia significantly downregulates Cl- co-transporter KCC2 expression but NKCC1 expression which is the Cl- importer remains unaffected with trends of upregulation in post-ischemic brains. Rescuing the pathophysiological hypofunction of KCC2 following ischemic insults is an untested strategy in neonatal brains. Hypothesis: Rescuing KCC2 hypofunction in neonatal ischemia will restore the physiological levels of synaptic inhibition and neuronal network activity. This rescue will prevent the emergence of refractory seizures and successfully reduce seizure burdens with GABA agonists which in turn will be disease modifying in the long-term. Aims: 1.Plot the dynamics of early and acute KCC2 degradation following ischemia and investigate the regulation of intrinsic KCC2 hypofunction during ischemic seizures. 2. Document the KCC2 degradation related depolarization of cortical neurons following ischemia and the effects of a KCC2 agonist on such depolarization in-vitro 3. Rescue refractory ischemic - seizures in-vivo with a novel KCC2 agonist and quantitate effect on long-term co-morbidities. Deliverables: Upon successful completion of this project, we will move closer to understanding the link between the dynamic changes of KCC2 expression during neonatal seizures to the emergence of refractoriness. Impact and Innovation: Understanding the mechanisms by which the immature brain is transformed with repeated seizures in the neonatal period will help guide evidence-based strategies into treatments for intractable seizures that are often associated with severe long-term co-morbidities in children.