Novel Brain-Selective Conditional Knockout of the Norepinephrine Transporter

描述（由申请人提供）：本提案的目的是开发产生去甲肾上腺素转运蛋白（NET）基因条件性敲除的新型小鼠模型。这项工作的总体目标是阐明NET在中枢与外周交感神经系统（CNS与SNS）去甲肾上腺素能神经元中的作用，以影响精神病表型，并激发新的治疗方法。越来越多的证据表明脑和心血管疾病之间存在显著的共病。例如，焦虑症患者主诉心悸，心动过速障碍患者的焦虑发生率较高。这些合并症是如何从共同的遗传风险因素中衍生出来的，目前还知之甚少。控制情绪和心血管功能的电路的一个共享组件是神经递质，去甲肾上腺素（NE）。在脑和心脏中的突触处释放的NE通过由突触前定位的NET主动转运到终末而失活，使得NET成为NE失活和突触前儿茶酚胺稳态的关键介质。我们已经证明，组成性NET敲除或敲入非功能性NET突变A457 P的小鼠表现出心动过速和焦虑。我们现在已经产生了第一只具有“floxed”NET等位基因的小鼠，以允许选择性NET敲除来剖析CNS与SNS对精神疾病的贡献。迄今为止，很少有研究的启动子，可以驱动表达的去甲肾上腺素能神经元选择性地在中枢神经系统与SNS。该提议将确定CRE驱动线选择性地敲除中枢与外周去甲肾上腺素能神经元中的NET的能力。目的：我将CRE系与Rosa报告小鼠和NET floxed小鼠交叉，据报道，CRE系驱动脑或SNS NE神经元的重组。我们将确定报告基因的表达，以及NET在大脑和SNS中的表达和活性。目的二将确定是否焦虑/抑郁相关行为观察到的构成操纵的NET是由大脑与SNS NET。这些研究引入了新的科学思想，使用遗传解剖大脑与SNS去甲肾上腺素能功能，并提供了一种新的表征工具来实现这一点。这些模型将转化为去甲肾上腺素能神经元中具有组织特异性表达的许多其他基因的研究。这项工作将使我们能够更准确地了解大脑去甲肾上腺素能信号在精神障碍中的作用。

DESCRIPTION (provided by applicant): The aim of this proposal is to develop novel mouse models that produce conditional knockout of the norepinephrine transporter (NET) gene. The overarching goal of this work is to elucidate the role of NET in central versus peripheral sympathetic nervous system (CNS vs. SNS) noradrenergic neurons to influence psychiatric phenotypes, and inspire new treatments for such disorders. Increasing evidence indicates significant comorbidities between brain and cardiovascular disorders. For example, patients with anxiety complain of heart palpitations and patients with tachycardia disorders have a higher incidence of anxiety. How these comorbidities derive from shared genetic risk factors is poorly understood. One shared component of circuits controlling mood and cardiovascular function is the neurotransmitter, norepinephrine (NE). NE released at synapses in the brain and heart is inactivated through active transport into terminals by the presynaptically- localized NET, making NET a critical mediator of NE inactivation and presynaptic catecholamine homeostasis. We have demonstrated that mice with a constitutive NET knockout or knock-in of a non-functional NET mutation, A457P, exhibit both tachycardia and anxiety. We have now generated the first mouse with a "floxed" NET allele to allow selective NET knockout to dissect CNS vs. SNS contributions to psychiatric disease. There has been little study to date of promoters that can drive expression in noradrenergic neurons selectively in the CNS versus SNS. This proposal will determine the ability of CRE driver lines to selectively knock out NET in central versus peripheral noradrenergic neurons. Aim I will cross CRE lines that reportedly drive recombination in either brain or SNS NE neurons with Rosa reporter mice and NET floxed mice. We will determine reporter expression, and NET expression and activity in the brain and SNS. Aim II will determine if anxiety/depression- related behaviors observed with constitutive manipulation of NET are driven by brain versus SNS NET. These studies introduce the novel scientific idea to use genetic dissection of brain versus SNS noradrenergic function, and provide a novel characterization of tools to accomplish this. These models will translate to the study of many other genes with tissue-specific expression in noradrenergic neurons. This work will allow us to more precisely understand the role of brain noradrenergic signaling in mental disorders.