Investigation of an Optogenetic Vagus Nerve Stimulation Device in an Animal Model of Post-traumatic Stress Disorder

这项拟议的研究将开发一种新的光遗传迷走神经刺激系统，并研究 迷走神经刺激对创伤后应激障碍(PTSD)啮齿动物模型的影响。 利用自主神经系统的周围神经进行的治疗干预越来越多地被 考虑并应用于疾病治疗的器官功能调节。迷走神经刺激(VNS)有 20多年来一直被临床批准用于治疗癫痫发作和抑郁症。它还 在类风湿性关节炎等炎症性疾病的治疗中显示出积极的临床结果 和克罗恩病，而临床和临床前数据表明，心脏疾病和 糖尿病。迷走神经的胆碱能(副交感)通路是 观察到的治疗效果。“胆碱能抗炎途径”是一种既定的信号。 促炎症细胞因子在脾和脾组织中的表达和释放减少的机制 在其他内脏组织中。因为炎症是许多疾病的驱动力，调控的能力 炎症介质是人们的主要兴趣所在。在最先进的迷走神经电刺激(VNS)中， 然而，电流被广泛地施加到神经上，这种刺激的非特异性性质激活了- 给患者造成不良影响的靶路径，而且不能提供足够的精确度 研究和理解与治疗相关的神经通路。拟议的研究将发展和 应用光遗传系统进行迷走神经刺激，可以消除这些偏离目标的并发症。 有了光遗传工具，光敏致动器可以通过基因打靶作用于感兴趣的细胞类型 和组织特异性病毒传递，从而使神经回路的高度特异性激活和研究成为可能。 这种神经调节方法将应用于创伤后应激障碍，这是美国退伍军人中非常普遍的负担 人口。创伤后应激障碍与炎症升高高度相关，并经常与许多 上述疾病。除了迷走神经的抗炎途径外，有益于 在精神疾病和炎症性疾病中观察到的影响表明，迷走神经刺激可能对 在啮齿动物模型中治疗创伤后应激障碍，甚至是VNS，可以增强恐惧消退，减少焦虑。海流 这项研究将为光遗传学研究开发一种3D打印的迷走神经袖带系统(目标1)。这种生物相容的 单组分、光刺激神经植入将使一种易于制造和易于植入的装置成为可能 用于慢性刺激。该系统的有效性和寿命将通过评估心脏 在创伤后应激障碍小鼠身上测试该系统之前，对手术植入的小鼠的纵向反应性(目标2) 模型(目标3)。将使用先前描述的单个电击足电击方案来条件联合 恐惧是一种条件性刺激--震荡室。光基因靶向传出的迷走神经刺激 (胆碱能)和/或传入(谷氨酸能)纤维亚型将与暴露于 条件刺激持续时间为5天。恐惧的消退和焦虑水平的衡量 加迷宫试验将在刺激和非刺激的对照动物中进行评估。

The proposed research will develop a novel system for optogenetic vagus nerve stimulation and investigate the impact of vagal stimulation in a rodent model of post-traumatic stress disorder (PTSD). Therapeutic interventions using peripheral nerves of the autonomic nervous system are increasingly being considered and applied to modulate organ function for disease treatments. Vagus nerve stimulation (VNS) has been clinically approved for over two decades for its treatment of epileptic seizures and depression. It has also demonstrated positive clinical outcomes in the treatment of inflammatory disorders such as rheumatoid arthritis and Crohn’s disease, while clinical and pre-clinical data suggest therapeutic benefit in heart disease and diabetes. Cholinergic (parasympathetic) pathways of the vagus nerve are an important factor in the therapeutic effects that are observed. The ‘cholinergic anti-inflammatory pathway’ is an established signaling mechanism by which the expression and release of pro-inflammatory cytokines are reduced in the spleen and in other visceral tissues. Because inflammation is a driver of numerous diseases, the ability to regulate inflammatory mediators is of major interest. In state-of-the-art electrical vagus nerve stimulation (VNS), however, current is applied broadly to the nerve and the non-specific nature of this stimulation activates off- target pathways causing adverse effects to the patient, and furthermore, does not provide adequate precision to study and understand therapeutically relevant nerve pathways. The proposed research will develop and apply an optogenetic system for vagus nerve stimulation that can eliminate these off-target complications. With optogenetic tools, light-sensitive actuators can be targeted to cell-types of interest via genetic targeting and tissue-specific viral delivery, thus enabling highly specific activation and investigation of neural circuits. This neuromodulation methodology will be applied to PTSD, a highly prevalent burden among the U.S. Veteran population. PTSD is highly correlated with elevated inflammation and often co-morbid with many of the diseases mentioned above. In addition to the anti-inflammatory pathways of the vagus nerve, beneficial impacts observed in psychiatric and inflammatory disorders suggest that vagal stimulation may be effective in treating PTSD, and indeed, VNS in rodent models enhances fear extinction and reduces anxiety. The current study will develop a 3D-printed vagus nerve cuff system for optogenetic studies (Aim 1). This biocompatible, single-component, optical stimulation nerve implant will enable an easy-to-fabricate and easy-to-implant device for chronic stimulation. The effectiveness and longevity of the system will be validated by assessing cardiac responsivity longitudinally in surgically implanted mice (Aim 2), before testing the system in a PTSD mouse model (Aim 3). A previously described single electric footshock protocol will be used to condition associative fear to a conditioned stimulus – the shock chamber. Vagal stimulation of optogenetically targeted efferent (cholinergic) and/or afferent (glutamatergic) fiber subtypes will be applied concurrently with exposure to the conditioned stimulus over a period of 5 days. Extinction of fear, and anxiety level measured with the ‘elevated plus maze’ test will be assessed in stimulated and non-stimulated control animals.