GLP1R neurons in the subfornical organ and integration of thirst and satiety cues

项目摘要 在感觉生物学方面的发现不仅塑造了我们的生活方式，而且对 人类健康。我的长期职业目标是更好地了解环境线索是如何被检测到的，以及 编码在外围，并与大脑通信，控制健康和健康的生理和行为 疾病。我在这份提案中描述的当前目标是调查GLP-1是如何集中通信的 用穹隆下器官控制水分摄入量和体液平衡。维持液体动态平衡是 对健康和疾病至关重要。高糖引起的循环渗透压升高导致糖尿病患者多饮 病人。涉及模拟或稳定胰高血糖素样肽1(GLP-1)的胰岛素疗法提供了一种 2型糖尿病的治疗策略。作为一种胰岛素，GLP-1不仅控制胰岛素的释放和摄食 行为还能调节血压、肾脏钠的排泄和液体的摄入，以协调促进 餐后系统水平的消化。耐人寻味的是，急性服用GLP-1会引起饮酒减少和 有效地减少健康受试者和糖尿病患者的用水量，提出了一种替代方案 减轻糖尿病患者多饮的策略。在许多表达GLP受体的位点中- 1(GLP1R)，穹隆下器官是控制水分摄入和液体动态平衡的主要大脑中枢。我的 中心假说是SFO GLP1R神经元在餐后整合饱腹感信号以控制液体摄入 通过特定的信号级联和中枢神经回路。我将通过三个具体的例子来检验这一假设 目的：确定刺激SFO GLP1R神经元对液体摄入的影响(特定目标1)，以破译 GLP1R在这些细胞中的信号通路(特定目标2)，并仔细研究它们的解剖和功能 连通性(具体目标3)。对于特定目标2所需的培训，我将继续受益良多 在我的导师Liberles教授的指导下，他对GPCR有着令人难以置信的知识和理解 信号通路。为了实现具体的目标1和3，我还需要扩大我的知识和技能，以 包括老鼠行为和神经回路映射，例如立体定向脑外科手术、脑切片 电生理学和化学遗传学。这些知识和技能将通过与我的同事一起培训来获得 导师布拉德福德·洛厄尔教授。我从洛厄尔教授和他的实验室成员那里得到了极大的指导 过去，随着GLP1R-Ires-Cre小鼠的产生和脑立体定向注射。我会继续学习Brain 切片记录、基于狂犬病病毒的跟踪、通道视紫红质辅助电路映射(CRACM)，以及 DREADD-在洛厄尔教授的指导下进行的行为实验。尤其是关于 SFO GLP1R神经元的解剖示踪(特定目标3)，需要非常广泛的大脑知识 解剖学，我将与Clifford Saper教授合作，他是一位有40多年神经解剖学经验的专家 经验。总之，这些研究将极大地扩展我们对GLP-1信号如何整合到 大脑协调控制生理，并阐明了基于GLP-1的药物设计。

Project Summary Discoveries made in sensory biology not only shape the way we live, but also have important repercussions for human health. My long-term career goal is to better understand how environmental cues are detected and encoded in the periphery, and communicated with the brain to control physiology and behavior in health and disease. My current objective described in this proposal is to investigate how GLP-1 communicates centrally with the subfornical organ to control water intake and body fluid homeostasis. Maintaining fluid homeostasis is crucial for health and disease. Elevation of circulatory osmolarity by high glucose causes polydipsia in diabetic patients. Incretin therapies that involve mimicry or stabilization of glucagon-like peptide 1 (GLP-1) provide a strategy for treatment of type 2 diabetes. As an incretin, GLP-1 not only controls insulin release and feeding behavior but also regulates blood pressure, renal excretion of sodium, and fluid intake to coordinately promote digestion at a systematic level after meal. Intriguingly, acute GLP-1 administration elicits hypodipsia and effectively reduces water consumption in both healthy subjects and diabetic patients, suggesting an alternative strategy for alleviating polydipsia in diabetic patients. Among the many sites that express the receptor for GLP- 1 (GLP1R), the subfornical organ is a major brain center that controls water intake and fluid homeostasis. My central hypothesis is that SFO GLP1R neurons integrate satiety signals after meal to control fluid intake through specific signaling cascades and central neural circuits. I will test this hypothesis through three specific aims: to determine the effect of SFO GLP1R neuron stimulation on fluid intake (Specific Aim 1), to decipher GLP1R signaling pathways in these cells (Specific Aim 2), and to scrutinize their anatomical and functional connectivity (Specific Aim 3). For the training necessary for Specific Aim 2, I will continue to greatly benefit from the guidance of my mentor Prof. Liberles, who has incredible knowledge and understanding in GPCR signaling pathways. To carry out Specific Aim 1 and 3, I will also need to broaden my knowledge and skills to include mouse behavior and neurocircuit mapping, such as stereotaxic brain surgeries, brain slice electrophysiology, and chemogenetics. Such knowledge and skills will be obtained from training with my co- mentor, Prof. Bradford Lowell. I have received tremendous guidance from Prof. Lowell and his lab members in the past, with generation of Glp1r-ires-Cre mice and brain stereotaxic injection. I will continue to learn brain slice recording, rabies virus-based tracing, channelrhodopsin-assisted circuit mapping (CRACM), and DREADD-involved behavioral experiments under the guidance of Prof. Lowell. Particularly regarding the anatomical tracing of SFO GLP1R neurons (Specific Aim 3) that requires very extensive knowledge of brain anatomy, I will collaborate with Prof. Clifford Saper, who is an expert in neuroanatomy more than 40 years experience. Together, these studies will greatly expand our knowledge on how GLP-1 signal is integrated in the brain to coordinately control physiology and shed light on GLP-1 based drug design.