Evaluation of Dbx1-derived neurons as the core rhythm generators in mammalian res

描述(申请人提供)：哺乳动物的呼吸是一种重要的行为，其潜在的神经机制起源于脑干。该项目旨在确定在哺乳动物(包括人类)中产生和控制呼吸的脑干神经回路的组成部分，从而对人类健康具有重大影响。延髓腹侧的一个部位称为前Botzinger复合体(PreBotzinger Complex)，它对呼吸是必不可少的。然而，就其所包含的不同细胞群体的遗传和发育特性及其生理特性而言，前BotC的细胞组成在很大程度上仍不清楚。假设前BotC中遗传上不同的神经元亚群形成了产生呼吸节律的核心。为了评估这些关键神经元的作用，采用了结合分子遗传学和电生理学的多学科研究方法。最近发展起来的通过遗传方法传递细胞谱系标记的技术，如定点重组和荧光标记，已经极大地影响了神经发育的研究。用重组酶融合的细胞谱系示踪剂和报告转基因设计的转基因敲入小鼠模型是该研究项目的重要组成部分。同样，这些遗传上不同的神经元群体的特征是通过使用独特的体外脑干切片制备的电生理记录来进行的，该制备含有必要的呼吸神经回路，并允许在细胞水平和系统水平记录呼吸运动输出。因此，这项研究项目可以用多层次的方法来评估关键神经元群体在呼吸中的重要性：将分析分子、细胞和系统级别的属性。具体目标1将通过可逆的遗传沉默和不可逆的激光损伤来评估这些神经元的节律作用。特定目标2将通过全细胞记录来评估与其节律作用相一致的关键神经元的膜特性。这个项目将阐明哺乳动物呼吸的神经起源。本项目获得的新知识将促进我们对中枢神经系统功能障碍引起的呼吸系统疾病的诊断和治疗的理解，并提供关于节律生成的关键新知识，这通常适用于了解大脑功能。 与公共健康相关：呼吸是人类的一种行为，对维持生命至关重要。该项目旨在揭示产生和控制呼吸节律的脑干神经回路的细胞组成，并表征这些细胞的特性与它们作为节律生成器的角色一致。获得的新知识将有助于诊断和治疗具有中枢神经病因学的呼吸系统疾病，并阐明总体上支持节律性运动行为的神经机制。

DESCRIPTION (provided by applicant): Mammalian breathing is a vital behavior whose underlying neural mechanism originates in the brainstem. This project aims to determine the components of the brainstem neural circuits that generate and control respiration in mammals, including humans, and thus has significant implications for human health. A site in the ventral medulla called preBotzinger Complex (preBotC) is essential for breathing. However, the cellular composition of the preBotC, in terms of the genetic and developmental identity of the different cell populations it contains, and their physiological properties, remain largely unknown. A genetically distinct subpopulation of neurons in the preBotC is hypothesized to form the kernel that generates respiratory rhythm. To evaluate the role of these key neurons, a multidisciplinary research approach is employed that combines molecular genetics and electrophysiology. Recently developed technologies that deliver cell lineage markers via genetic methods, such as site-specific recombination and fluorescent tagging, have greatly impacted neural development studies. Transgenic knock-in mouse models engineered with recombinase-fused cell lineage tracers and reporter transgenes are essential components of the research project. Likewise, characterization of these genetically distinct neuronal populations is carried out through electrophysiological recordings using a unique in vitro brainstem slice preparation that contains essential respiratory neural circuits and allows both cellular-level and systems-level recordings of respiratory motor output. Thus, this research project can evaluate the importance of the key population of neurons in breathing with a multilevel approach: molecular, cellular and system-level properties will be analyzed. Specific Aim 1 will assess the rhythmogenic role of these neurons through reversible genetic silencing and irreversible laser lesioning. Specific Aim 2 will evaluate the membrane properties of the key neurons consistent with their rhythmogenic role through whole-cell recordings. This project will elucidate the neural origins of mammalian respiration. The new knowledge obtained in this project will advance our understanding in the diagnosis and treatment of respiratory disorders that result from dysfunctions in the central nervous system, and provide key new knowledge regarding rhythm generation, which is generally applicable to understanding brain function. PUBLIC HEALTH RELEVANCE: Breathing is a human behavior that is essential in maintaining life. This project aims to reveal the cellular composition of brainstem neural circuits that generate and control breathing rhythms, and to characterize the properties of these cells consistent with their role as rhythm generators. The new knowledge acquired will facilitate the diagnosis and treatment of respiratory disorders with a central neural etiology, and elucidate the neural mechanisms that underlie rhythmic motor behaviors in general.