Project 3: Normalization of Neuronal Excitability

项目概要-项目3 临床和临床前数据都清楚地表明，OP诱导的癫痫持续状态（SE）的幸存者可以 发生持续性神经病理学、自发性复发性癫痫发作（SRS）和认知功能障碍。电流 急性OP中毒的标准护理（SOC）包括毒蕈碱受体拮抗剂，阿托品， 与肟如氯解磷定（2-PAM）组合以重新激活乙酰胆碱酯酶，最后， 苯二氮卓类药物增加抑制性张力。然而，现在很清楚，SOC预防SE或 抵消OP诱导的胆碱能风暴的下游后果的能力随时间迅速减弱。 具体地说，立即用阿托品和2-PAM治疗可以增加生存力，但不能防止 过渡到SE。一旦处于SE状态，苯二氮卓类药物中断癫痫发作和防止持续发作的可能性 细胞死亡率迅速下降。同样清楚的是，随着急性中毒和治疗之间的间隔时间的增加， 相应的慢性神经缺陷的严重性也增加。很可能在一个大规模的 在伤亡事件中，对接触化学威胁制剂的平民的治疗将超出最佳范围， 治疗窗口，增加他们将发展持续性SRS和认知障碍的可能性。 因此，明确需要鉴定生物标记物以鉴定具有最高风险的个体。 发展长期发病率，并超越急性OP中毒的管理， 并研究管理慢性神经系统后遗症的治疗策略，包括SRS和 认知功能障碍在项目3中，我们将首先评估急性DFP中毒的自然史。这将 包括对整个过程中从深度和皮质电极记录的神经振荡进行严格评估 损伤后4个月，SRS的定量和标准电池的评估， 认知结果（Y-迷宫，新物体识别和上下文恐惧条件反射）， 相关的触摸屏行为（评估记忆，执行功能和注意力）。我们将评估 四种治疗候选药物，它们具有调节兴奋性、恢复振荡、减少癫痫发作和 提高认知能力。这些候选物包括：（i）FDA批准的拉考沙胺，其增强缓慢的 电压门控钠通道（Nav）的失活;（ii）FDA批准的利鲁唑，其阻断Nav，但也 增强小电导钙激活钾通道（KCa）和谷氨酰胺的活性 （iii）SKA-19，一种混合的Nav阻断剂和KCa激活剂;和（iv）NS 13001，一种相对选择性的KCa 活化剂。最后，我们将确定包括上述治疗药物之一的组合疗法的潜力。 接受θ频率脑深部电刺激的候选人，以进一步管理慢性神经系统结局 与急性OP中毒有关。最终，项目3将揭示毒性的分子机制， 潜在地鉴定新的治疗靶点以预防（用鉴定的疗法的急性递送）或治疗（用 慢性分娩）的毁灭性的长期神经后遗症，包括SRS和认知功能障碍。

Project Summary – Project 3 Both clinical and preclinical data clearly demonstrate that survivors of OP-induced status epilepticus (SE) can develop persistent neuropathology, spontaneous recurring seizures (SRS) and cognitive dysfunction. Current standard-of-care (SOC) for acute OP intoxication includes the muscarinic receptor antagonist, atropine, combined with an oxime, such as pralidoxime chloride (2-PAM) to reactivate acetylcholinesterase and finally a benzodiazepine to increase inhibitory tone. However, it is now clear that the potential for SOC to prevent SE or to counteract the downstream consequences of the OP-induced cholinergic storm rapidly diminishes with time. Specifically, immediate treatment with atropine and 2-PAM can increase viability, but does not prevent a transition into SE. Once in SE, the potential for benzodiazepines to interrupt seizures and protect against ongoing cell death quickly declines. It is also clear that as the interval between acute intoxication and treatment increases, the severity of the corresponding chronic neurological deficits increases as well. It is likely that following a mass casualty event, treatment of civilians exposed to chemical threat agents is going to fall outside of the optimal therapeutic window, increasing the likelihood that they will develop persistent SRS and cognitive disorders. Therefore, there is a clear need to identify biological markers to identify those individuals with the highest risk of developing long-term morbidity and also to move beyond the management of acute OP intoxication in the field, and to investigate therapeutic strategies for managing chronic neurological sequelae, including SRS and cognitive dysfunction. In Project 3, we will first evaluate the natural history of acute DFP intoxication. This will include a rigorous assessment of neural oscillations recorded from depth and cortical electrodes over the course of four months following injury, the quantification of SRS and also evaluation of both a standard battery of cognitive outcomes (Y-maze, novel object recognition and contextual fear conditioning) and also translationally relevant touchscreen behaviors (that evaluate memory, executive function, and attention). We will then evaluate four therapeutic candidates for their potential to modulate excitability, restore oscillations, reduce seizures and improve cognition. These candidates include: (i) FDA-approved lacosamide, which enhances the slow inactivation of voltage-gated sodium channels (Nav); (ii) FDA-approved riluzole, which blocks Nav, but also enhances the activity of small-conductance calcium-activated potassium channels (KCa) and also glutamine transport; (iii) SKA-19, a mixed Nav blocker and KCa activator; and (iv) NS13001, a relatively selective KCa activator. Finally, we will determine the potential of combinatorial therapy including one of the above therapeutic candidates with theta frequency deep brain stimulation to further manage the chronic neurological outcomes associated with acute OP intoxication. Ultimately, Project 3 will uncover molecular mechanisms of toxicity and potentially identify novel therapeutic targets to prevent (with acute delivery of identified therapies) or treat (with chronic delivery) the devastating long-term neurological sequelae, including SRS and cognitive dysfunction.