Selective Activation of Neurons to Control Narcolepsy

描述(申请人提供)：基因转移已被证明是治疗一些神经退行性疾病的有效神经生物学工具，我们已经使用它来纠正一种睡眠障碍。我们关注的是发作性睡病，这是一种神经退行性睡眠障碍，与含有神经肽下分泌素(也称为增食欲素)的神经元丢失有关。为了恢复食欲素水平，我们将食欲素基因插入到代理神经元中，并阻止了两种可靠有效的发作性睡病小鼠模型的发作性睡病行为。这种影响是特定部位的，并依赖于代理神经元的连接性。我们现在建议通过限制食欲素仅在MCH神经元中的表达并在清醒时选择性地激活它们来进一步缩小位置特异性。在人类发作性睡病中，MCH神经元仍然存在，并与食欲素神经元连接到相同的下游靶点。这些神经元在清醒时通常是沉默的，我们假设，通过在清醒时选择性地激活它们，我们将阻止猝发，并延长清醒的发作时间。在目标1中，我们将光敏感的阳离子通道通道视紫红质-2(ChR2)和增食欲素的基因插入MCH神经元(MCH启动子驱动)。光遗传刺激将驱动含有MCH-ChR2-oresin的神经元，其对猝倒和觉醒持续时间的影响将在昼夜周期中确定。AIM 2将利用一种新的方法，依赖于专门由设计药物激活的设计受体来激活MCH神经元。建议进行适当对照的实验，包括食欲素受体拮抗剂，以加强这一结论。C-Fos将确定MCH神经元的激活，体外钙成像研究将确定基因插入的ChR2和hM3Dq受体的功能。这些研究将首次确定可以选择性激活以阻止发作性睡病行为的神经元。

DESCRIPTION (provided by applicant): Gene transfer has proven to be an effective neurobiological tool in a number of neurodegenerative diseases and we have used it to correct a sleep disorder. We have focused on narcolepsy, a neurodegenerative sleep disorder linked to the loss of neurons containing the neuropeptide hypocretin, also known as orexin. To restore orexin levels we have inserted the gene for orexin into surrogate neurons and blocked narcoleptic behavior in two reliable and valid mice models of narcolepsy. The effects were site specific and depended on the connectivity of the surrogate neurons. We now propose to further narrow the site-specificity by confining expression of orexin only in MCH neurons and selectively activating them during waking. The MCH neurons are still viable in human narcolepsy and are connected to the same downstream targets as the orexin neurons. These neurons are normally silent during waking and we hypothesize that by selectively activating them during waking we will block cataplexy and lengthen waking bouts. In aim 1 we will insert the genes for channelrhodopsin-2 (ChR2), a light sensitive cation channel, and orexin only in MCH neurons (MCH promoter driven). Optogenetic stimulation will drive the MCH-ChR2-Orexin containing neurons and its effects on cataplexy and wake duration will be determined during both the day and night cycles. Aim 2 will utilize a new emerging methodology that relies on Designer Receptors Exclusively Activated by Designer Drugs to activate the MCH neurons. Experiments with appropriate controls, including orexin receptor antagonist are proposed to strengthen the conclusions. C-Fos will identify activation of the MCH neurons and an in vitro calcium imaging study will determine functionality of the genetically inserted ChR2 and hM3Dq receptors. These studies will for the first time identify neurons that can be selectively activated to block narcoleptic behavior.