Area postrema neurons that mediate nausea-associated behaviors

项目摘要 恶心是一种内脏不适的不愉快感觉，具有潜在的分子和神经元通路 保持神秘。目前的抗恶心药物在患者队列中显示出不同的成功率， 恶心是癌症患者不能坚持治疗方案的主要原因。新战略 恶心干预是必要的，并且可能通过机械地理解恶心的感觉如何来实现。 恶心产生。涉及脑损伤和刺激的经典研究揭示了一个微小的脑结构， 对几种内脏威胁产生恶心反应的最后区。最后区是 脑室周围器官，含有脑内感觉神经元，在解剖学上准备接受 来自循环因子和迷走神经传入的输入。然而，最后区细胞类型的多样性和 受体是以前未知的。 在初步数据中，我们通过单核RNA测序建立了最后区细胞图谱，揭示了 四种兴奋性和三种抑制性神经元类型。转录组分析显示， 在不同的神经元簇中，以及许多引导细胞反应的细胞表面受体。我们 产生Cre基因敲入小鼠，用于遗传访问各种最后区神经元，并采用适应性方法 用于细胞特异性化学遗传学、光遗传学、消融、成像和解剖映射。我们发现了两 兴奋性神经元类型（集群2和4），提供强大的厌恶教学信号，和一个（集群1） 那不一样。在目标1中，我们将使用遗传工具来询问细胞簇2和4以及它们的受体是否存在。 对一组恶心诱导刺激表达、调节行为反应。在目标2中，我们将测量 细胞簇2和4对体液因子、遗传定义的迷走神经传入和各种恶心的反应- 诱导刺激。在目标3中，我们将研究最后区新绘制的抑制性神经元的作用， 其在局部投射并且是抑制恶心或其他由最后区介导的 行为。总之，这些实验将揭示最后区电路的基本组织， 提供了一个框架，以了解和治疗控制恶心。

Project Summary Nausea is an unpleasant sensation of visceral malaise, with underlying molecular and neuronal pathways remaining mysterious. Current anti-nausea medications display variable success across patient cohorts, with nausea being the major reason why cancer patients cannot adhere to treatment regimens. New strategies for nausea intervention are needed, and may be enabled by a mechanistic understanding of how the sensation of nausea arises. Classical studies involving brain lesion and stimulation revealed a tiny brain structure termed the area postrema that mediates nausea responses to several visceral threats. The area postrema is a circumventricular organ containing brain-resident sensory neurons that are anatomically poised to receive inputs from both circulating factors and vagal afferents. However, the diversity of area postrema cell types and receptors was previously uncharted. In preliminary data, we built an area postrema cell atlas through single-nucleus RNA sequencing, revealing four excitatory and three inhibitory neuron types. Transcriptome analysis revealed signature genes expressed in different neuronal clusters, as well as many cell surface receptors that guide cellular responses. We generated Cre knock-in mice for genetic access to various area postrema neurons, and adapted approaches for cell-specific chemogenetics, optogenetics, ablation, imaging, and anatomical mapping. We found two excitatory neuron types (clusters 2 and 4) that provide powerful aversion teaching signals, and one (cluster 1) that does not. In Aim 1, we will use genetic tools to ask whether cell clusters 2 and 4, and the receptors they express, mediate behavioral responses to a panel of nausea-inducing stimuli. In Aim 2, we will measure the responses of cell clusters 2 and 4 to humoral factors, genetically defined vagal afferents, and various nausea- inducing stimuli. In Aim 3 we will investigate the roles of newly charted inhibitory neurons in the area postrema, which project locally and are excellent candidates to suppress nausea or other area postrema-mediated behaviors. Together, these experiments will reveal the basic organization of area postrema circuitry, and provide a framework towards understanding and therapeutically controlling nausea.