Behavioral, molecular and genetic studies of VIP in the SCN

描述(申请人提供)：下丘脑的视交叉上核(SCN)由大约20,000个神经元组成，这些神经元共同作用，在哺乳动物中产生天生的生物钟。这一时钟由包括周期1(PER1)在内的昼夜节律基因表达的转录和翻译反馈环维持。SCN的节律是由光信号通路设定并与外部环境同步的，其中包括血管活性肠肽(VIP)，VIP在光刺激下上调PER1的表达。生物钟功能障碍与人类各种形式的抑郁和睡眠障碍有关，并已被证明在动物模型中具有戏剧性的行为后果。本提案试图回答以下关于VIP在SCN中的作用的具体问题：第一，在VIP和Vipr2(VIP受体)基因敲除小鼠中，SCN是如何组织的，这种组织如何解释行为输出？第二，跑轮对这些动物的行为特征有什么影响？在VIP和Vipr2基因缺陷的小鼠中，VIP的行为作用将通过滚轮和红外运动检测来研究。利用mPer1：：GFP(绿色荧光蛋白)转基因报告系，利用共聚焦显微镜对VIP和Vipr2基因缺陷小鼠的SCN进行实时昼夜节律基因表达分析。这些都是在我们的实验室以及与合作者一起使用的非常成功的新颖方法。生物钟功能失调会极大地影响人类健康。例如，季节性情感障碍(SAD)是当人体时钟在冬季获得的光输入较少时发生的，每年影响多达3%的美国人口。这种疾病的治疗方法是光疗和选择性5-羟色胺再摄取抑制剂(SSRI)--这是哺乳动物体内血管活性肠肽的两种调节剂。VIP在光夹带中的重要作用表明，该肽是一种基因申请者，可能对昼夜节律功能障碍有很大贡献。基因敲除的小鼠模型是最极端的证据，证明了如果VIP或Vipr2基因因突变或多态而改变会发生什么。这一证据表明，VIP能信号对人类健康很重要，对小鼠模型的研究可以为人类时钟及其在昼夜节律相关疾病中的功能障碍提供有价值的见解。

DESCRIPTION (provided by applicant): The suprachiasmatic nuclei (SCN) of the hypothalamus consists of about 20,000 neurons that function together to produce an innate biological clock in mammals. This clock is maintained by transcriptional and translational feedback loops of circadian gene expression including Period 1 (Per1). SCN rhythms are set by and synchronized with the external environment by light signaling pathways including vasoactive intestinal peptide (VIP), which upregulates the expression of Per1 upon stimulation by light. Dysfunction in the circadian clock has been linked to various forms of depression and sleep disorders in humans, and has been shown to have dramatic behavioral consequences in animal models. This proposal will attempt to answer the following specific questions regarding the role of VIP in the SCN: First, how is the SCN organized in VIP and Vipr2 (VIP's receptor) knockout mice, and how does this organization account for the behavioral output? Second, what influence does wheel-running have on the behavioral characteristics of these animals? The behavioral role of VIP will be investigated using wheel-running and infrared motion detection in VIP- and Vipr2-deficient mice. A mPer1::GFP (green fluorescent protein) transgenic reporter line will be used to perform real-time circadian gene expression analyses by confocal microscopy in the SCN of VIP- and Vipr2-deficient mice. These are novel and highly successful approaches used in our laboratory and in conjunction with collaborators. Circadian clock dysfunction can dramatically affect human health. Seasonal Affective Disorder (SAD), for example, occurs when the human clock gets less light input during the winter months and affects up to 3% of the United States population every year. The disease is treated with light therapy and selective serotonin reuptake inhibitors (SSRI)-two modulators of VIP in mammals. VIP's essential role in photic entrainment implicates the peptide as a genetic applicant that could contribute greatly to circadian dysfunction. The knockout mouse models are the most extreme evidence of what could happen if the VIP or Vipr2 genes are altered by mutation or polymorphism. This evidence suggests that VIP-ergic signaling is important to human health, and that the study of the mouse model can grant valuable insight into the human clock and its capacity for dysfunction in circadian-linked disease.