Mapping the developmental, genetic, and functional organization of noradrenergic respiratory neural circuits

 描述(申请人提供)本项目的目标是将不同的呼吸功能映射到脑干去甲肾上腺素能神经元上。包括SID、Rett综合征和CCHS在内的几种呼吸系统病理生理特征都以呼吸紊乱为特征，并与脑干去甲肾上腺素能系统异常有关，去甲肾上腺素能信号似乎在阻塞性睡眠呼吸暂停中起重要作用。在多个模型系统中，中央NA系统已被证明参与呼吸控制。然而，以前的实验技术，包括损伤、基因敲除和药物操作，都受到这些技术固有的不精确性的阻碍。为了清楚地描述和访问NA亚型，我们正在使用交叉遗传学来根据起源的菱形核来细分NA神经元。我们推测，每个菱形体固有的早期发育基因表达程序是NA系统组织成不同功能模块的基础，这些模块与中枢呼吸网络中的功能模块有关。在每个NA菱形体子集中，我们将使用新的小鼠交叉遗传工具来从解剖、功能和分子上绘制电路组织图。我们建议从三个不同的目标来检验我们的假设。在目标1中，我们将从解剖角度将NA菱形亚型投射映射到已知的脑干呼吸中心，以确定NA神经元的信息流。在目标2中，我们将使用药物遗传学(DREADD)神经元操作结合全身气压体积描记来将不同的呼吸功能分配给NA亚型。在目标3中，我们将通过分子图谱在分子水平上检验早期发育的菱形亚单位进入成年脑干的假说。由此得到的菱形NA亚型的解剖、功能和分子特征的综合框架将增加我们对中枢NA神经元组织及其在呼吸系统疾病中的作用的理解。最终，我们希望这种方法能够开发出高度针对性的诊断和治疗方法，这些诊断和治疗方法针对所需的作用部位，对NA系统所服务的其他行为和生理功能的副作用最小。

 DESCRIPTION (provided by applicant) the goal of this project is to map distinct respiratory functions onto brainstem noradrenergic neurons. Several respiratory pathophysiologies including SIDS, Rett syndrome, and CCHS feature both disordered breathing and are associated with brainstem noradrenergic system abnormalities and, noradrenergic signaling appears to be important in obstructive sleep apnea. In multiple model systems, the central NA system has been shown to be involved in respiratory control. However, prior experimental techniques, including lesions, gene knockouts, and pharmacological manipulations have been hampered by the imprecision inherent in these techniques. To clearly delineate and access NA subtypes, we are using intersectional genetics to subdivide NA neurons by rhombomere of origin. We hypothesize that the early developmental gene expression programs intrinsic to each rhombomere underlie the organization of the NA system into distinct functional modules with in the central respiratory network. Within each NA rhombomeric subset, we will use new mouse intersectional genetic tools to anatomically, functionally, and molecularly map circuit organization. We propose to test our hypothesis in three separate Aims. In Aim 1, we will anatomically map NA rhombomeric subtype projections to known brainstem respiratory centers to determine the flow of information from NA neurons. In Aim 2, we will use pharmacogenetic (Dreadd) neuron manipulations in combination with whole body barometric plethysmography to assign distinct respiratory functions to NA subtypes. In Aim 3, we will test the hypothesis that early developmental rhombomeric subdivisions carry into the adult brainstem at the molecular level through molecular profiling. The resulting integrated framework of anatomical, functional, and molecular characterizations across rhombomeric NA subtypes will add clarity to our understanding of central NA neuron organization and its role respiratory disorders. Ultimately, we expect this approach to enable the development of highly targeted diagnostics and therapeutics that are directed to the required sites of action with minimal side effects on the other behavioral and physiological functions served by the NA system.