Striatal Cholinergic Interneuron Dysfunction in Dystonia Pathophysiology

项目总结 DYT1肌张力障碍是最常见的遗传性肌张力障碍形式，是一种常见的致残神经运动 无序。纹状体功能障碍被认为在肌张力障碍的病理生理学中起关键作用，但目前还不清楚 神经元类别功能失调，并驱动异常运动。形态和电生理 在DYT1小鼠模型中观察到纹状体胆碱能中间神经元(CHI)的异常，但许多 这些模型中没有表现出运动功能障碍。这一研究肌张力障碍的障碍在 Dauer实验室通过有条件地敲除前脑中的TorsinA产生了一个明显有症状的小鼠模型 使用Dlx5/6-Cre(“DLX-CKO”)的胆碱能和GABA能神经元(包括所有纹状体神经元)。这些老鼠 表现为肌张力障碍样扭转运动，选择性背侧纹状体退行性变，形态和 存活的CHI的电生理改变。临床有效的抗毒鼠强药物抑制扭体反应 DLX-CKO小鼠的运动，建立了预测效度，并提示剩余的异常功能 (非退化性)气导致异常运动。为了探索这种可能性，我表演了 免疫组织化学方法检测标记物--磷酸化核糖体蛋白S6的表达强度 与CHI活性相关。我的初步数据显示TorsinA零位CHIS升高 磷酸化核糖体蛋白S6(p-rpS6)，这一发现与CHI活性改变一致。与 假设这些细胞的异常活动有助于肌张力障碍样运动，p-rpS6的增加是 对背侧纹状体(运动性)脑损伤有选择性，仅在有行为症状的年龄出现。以考察是否 异常的CHI信号是异常运动所必需的，我选择性地从纹状体中提取了这些细胞 在有症状和症状前年龄的DLX-CKO小鼠中进行研究，发现CHI消融可以逆转和防止 DLX-CKO小鼠的异常扭转运动，确立了它们在肌张力障碍样症状中的中心作用。 根据我的初步数据和大量已发表的电生理学研究，发现CHIS与肌张力障碍有关 病理生理学，我假设DLX-CKO小鼠CHI功能异常，并调节CHI 功能是一种有效的治疗策略。我将以两个目的来检验这一假设：(1)定义关系 在CHI活动和使用设计者独有激活的Designer受体的强直性截肢之间 药物(DREADD)技术和(2)确定TORINA表达的CHI靶向基因拯救是否拯救 DLX-CKO小鼠的神经病理和行为表型。拟议的研究将严格评估中国 仅有的有明显症状的肌张力障碍啮齿动物模型之一的功能障碍和治疗潜力。 拟议工作的完成将提高我的写作、技术和科学技能，并促进我的 作为一名专注于神经疾病的内科科学家的发展。

PROJECT SUMMARY DYT1 dystonia is the most common inherited form of dystonia, a common and disabling neurological movement disorder. Striatal dysfunction is thought to play a key role in dystonia pathophysiology, but it is unclear which neuronal classes are dysfunctional and drive abnormal movement. Morphologic and electrophysiologic abnormalities of striatal cholinergic interneurons (ChIs) have been observed in DYT1 mouse models, but many of these models do not exhibit motor dysfunction. This barrier to dystonia research was overcome when the Dauer lab generated an overtly symptomatic mouse model by conditionally knocking out torsinA from forebrain cholinergic and GABAergic neurons (including all striatal neurons) using Dlx5/6-Cre (“Dlx-CKO”). These mice exhibit dystonic-like twisting movements, selective degeneration of dorsal striatal ChIs, and morphologic and electrophysiologic changes in surviving ChIs. Clinically effective anti-muscarinic drugs suppress twisting movements in Dlx-CKO mice, establishing predictive validity and suggesting that aberrant function of remaining (non-degenerating) ChIs contributes to abnormal movement. To explore this possibility, I performed immunohistochemistry to determine intensity of phosphorylated ribosomal protein S6 (p-rpS6), a marker correlated with ChI activity. My preliminary data demonstrate that torsinA null ChIs exhibit elevated phosphorylated ribosomal protein S6 (p-rpS6), a finding consistent with altered ChI activity. Consistent with the hypothesis that abnormal activity of these cells contributes to dystonic-like movements, the p-rpS6 increase is selective to dorsal striatal (motor) ChIs and present only at behaviorally symptomatic ages. To examine whether abnormal ChI signaling is necessary for abnormal movement, I selectively lesioned these cells from the striatum of Dlx-CKO mice at symptomatic and pre-symptomatic ages and found that ChI ablation reverses and prevents abnormal twisting movements in Dlx-CKO mice, establishing their central role in dystonic-like symptoms. Based on my preliminary data and considerable published electrophysiological work implicating ChIs in dystonia pathophysiology, I hypothesize that ChIs are functionally abnormal in Dlx-CKO mice, and modulating ChI function is an effective therapeutic strategy. I will test this hypothesis with two aims: (1) defining the relationship between ChI activity and dystonic-like limb clasping using Designer Receptor Exclusively Activated by Designer Drugs (DREADD) technology and (2) determining if ChI-targeted genetic rescue of torsinA expression rescues neuropathologic and behavioral phenotypes in Dlx-CKO mice. The proposed studies will rigorously assess ChI dysfunction and therapeutic potential in one of the only overtly symptomatic rodent models of dystonia. Completion of the proposed work will further my writing, technical, and scientific skills and facilitate my development as a physician-scientist focused on neurologic disease.