Evaluating the therapeutic potential of vagal CART circuitry for treating metabolic disease

摘要 尽管进行了几十年的研究，但仍缺乏有效的肥胖治疗方法。考虑到肥胖的严重程度 流行，迫切需要有效减轻体重和维持体重的干预策略 减肥。支配肠道的迷走神经的结状神经节(NG)神经元是 提供负面反馈以终止一顿饭的营养传感机械。餐后信号被感觉到 通过肠道的迷走神经传入终末，信息集中传递到束核的神经元 孤独症(NTS)。NG表达的神经肽可卡因和苯丙胺调节转录本(CART) 神经元是控制卡路里摄入量的主要分子信号。在肥胖症中，迷走车的丢失足以 增加食物摄入量和体重。因此，我们假设在饮食诱导的肥胖中，恢复购物车 NG神经元的表达将导致自愿减少摄食量并在体重减轻后维持体重 干预措施。靶向CART和NG神经元支配CART的治疗潜力 (NGCART)我们将研究1)代谢信号如何整合到NGCART神经元中，2)这一信息是如何传递的 3)NG神经元过度表达CART对体重的影响。我们应用了强大的基因 以及迷走神经的分子神经科学工具，用于活体成像、连通性映射和靶向 在NGCART神经元中过表达。在目标1中，我们建议确定招募NGCART的代谢信号 通过将依赖于Cre的病毒示踪剂注射到CARTCre小鼠的NG中来映射神经元的投射和 NGCART神经元在肠道中的终末，并记录这些神经元在活体动物中的激活情况 一种基因定位的钙指示剂。在目标2中，我们将结合多突触电路跟踪和序列2 光子断层扫描绘制NGCART神经元通过大脑的突触电路。在目标3中，我们将使用cre- 依赖CART过表达病毒恢复CARTCre小鼠NGCART神经元CART表达 确定饮食引起的肥胖对摄食和体重的影响。这些研究将详细阐述 之前的工作是通过确定分子和细胞靶点，为开发 肥胖症的外围治疗。

ABSTRACT Despite decades of research, effective therapies for obesity are lacking. Given the magnitude of the obesity epidemic, there is a critical need for intervention strategies that effectively reduce body weight and maintain weight loss. Nodose ganglia (NG) neurons of the vagus nerve that innervate the gut are a key component of the nutrient sensing machinery that provides negative feedback to terminate a meal. Postprandial signals are sensed by vagal afferent terminals in the gut and the information is relayed centrally to neurons of the nucleus tractus solitarius (NTS). The neuropeptide cocaine and amphetamine regulated transcript (CART) expressed by NG neurons is a primary molecular signal that controls caloric intake. In obesity, loss of vagal CART is sufficient to increase food intake and body weight. Therefore, we hypothesize that in diet-induced obesity, restoring CART expression in NG neurons will cause voluntary reduction in food intake and sustain body weight after weight loss interventions. To evaluate the therapeutic potential of targeting CART and NG neurons innervating CART (NGCART) we will study 1) how metabolic cues are integrated in NGCART neurons, 2) how this information is relayed centrally, and 3) the impact of overexpressing CART in NG neurons on body weight. We apply powerful genetic and molecular neuroscience tools to the vagus nerve for in vivo imaging, connectivity mapping, and targeted overexpression in NGCART neurons. In aim 1, we propose to determine the metabolic signals that recruit NGCART neurons by using a Cre-dependent viral tracer injected into the NG of CARTCre mice to map the projections and terminals of NGCART neurons in the gut, and record the activation profile of these neurons in live animals by using a genetically targeted calcium indicator. In aim 2, we will combine multisynaptic circuitry tracing with serial two photon tomography to map NGCART neurons synaptic circuitry through the brain. In aim 3, we will use a cre- dependent CART overexpression virus to restore CART expression in NGCART neurons of CARTCre mice and determine the impact on feeding and body weight in diet induced obesity. These studies will elaborate on previous work by identifying a molecular and cellular target that can provide the foundation for developing peripheral treatments for obesity.