Satiety signaling in Caenorhabditis elegans

秀丽隐杆线虫的饱腹感信号传导

• 批准号: 8460012
• 负责人: Leon Avery
• 金额: $ 25.39万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2015-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8460012
• 关键词: Afferent Neurons; Animals; Anorexia; Behavior; Biological Models; Biology; Caenorhabditis elegans; Complex; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Desire for food; Disease; Eating; Environment; Epidemic; Fluorescence Recovery After Photobleaching; Food; Genes; Genetic; Genetic Epistasis; Genetic Models; Genetic Transcription; Goals; Health; Hormones; Human; Hunger; Insulin; Lasers; Lead; MAP Kinase Signaling Pathways; Mammals; Measures; Mediating; Metabolic; Methods; Microsurgery; Molecular; Motion; Muscarinic Acetylcholine Receptor; Mutate; Nematoda; Neurons; Nutritional; Obesity; Organism; Pathway interactions; Peptides; Personal Satisfaction; Persons; Proteins; Receptor Gene; Reverse Transcriptase Polymerase Chain Reaction; Satiation; Satiety Response; Signal Transduction; Site; Sleep; Source; Starvation; Synapses; Synaptic Vesicles; Testing; Time; base; behavior change; feeding; gain of function mutation; genome sequencing; knock-down; loss of function; mutant; novel; overexpression; promoter; public health relevance; response; sensor; tool; transgene expression

DESCRIPTION (provided by applicant): We propose to investigate the molecular mechanisms of appetite control in the nematode Caenorhabditis elegans. Just as in mammals, C elegans appetite is promoted by hunger signals and suppressed by satiety signals. Both responses to food availability are similar behaviorally and overlap in molecular mechanism with analogous mammalian behaviors. Based on this conservation, we aim to establish in C elegans a genetic model system to study appetite control. We anticipate that molecular mechanisms will be fundamentally similar to those of mammals, but simpler and therefore easier to unravel. Furthermore, the powerful genetic tools available in the worm will, we hope, allow rapid elucidation of new pathways, whose relevance to mammalian behavior can subsequently be tested. Our broad long-term objective is to understand at a molecular level how an animal regulates its food intake. Our goal in the next five years is to investigate the cellular and molecular mechanisms that control satiety. We will test the following hypotheses: 1. ASI sensory neuron activity signals nutritional well-being and provokes a satiety response. 2. ASI's effects are mediated by the release of peptide and protein hormones, including insulin-like peptides and the TGF-2-like peptide DAF-7. 3. Expression of satiety hormone genes increases in response to nutritional well-being. 4. Satiety hormones act on downstream neurons to change behavior. 5. Cyclic GMP (cGMP) activates cGMP-dependent protein kinase (PKG) in ASI and in downstream neurons to produce satiety. Aim 1. Identify satiety signaling mechanisms (hypotheses 1, 4, 5). Determine the time-course of satiety behavior in single worms. Determine the sites and times of action of signal and receptor genes in the insulin, TGF-2, and cGMP pathways by expression of transgenes from neuron-specific promoters in combination with laser microsurgery (hypotheses 2, 4, and 5). Determine the order of signal action by epistasis studies measuring the effects of overexpression and gain-of-function mutations in loss-of-function mutant backgrounds. Aim 2. Find peptide and protein hormone genes whose transcription correlates with satiety (hypotheses 2, 3). Using microarrays and quantitative RT-PCR, find peptide genes whose transcription is regulated by starvation and refeeding, or by cGMP and PKG. Mutate these genes or knock down their expression and determine the effect on satiety behavior. Screen for mutants defective in satiety- induced quiescence and identify the mutated genes by whole-genome sequencing.Aim 3. Measure synaptic activity and release of peptides from ASI (hypotheses 1, 2). Develop methods to measure synaptic activity by recovery of fluorescence after photobleaching of the synaptic vesicle pH sensor synaptopHluorin. Develop methods to measure release of fluorescent peptides from neurons. Use these methods to determine how ASI activity and peptide release respond to conditions that induce satiety.

描述（由申请人提供）：我们拟研究秀丽隐杆线虫食欲控制的分子机制。就像哺乳动物一样，线虫的食欲由饥饿信号促进，由饱腹信号抑制。这两种对食物供应的反应是相似的行为，在分子机制上与类似的哺乳动物行为重叠。基于这种保守性，我们的目标是在线虫中建立一个研究食欲控制的遗传模型系统。我们预计分子机制将从根本上与哺乳动物相似，但更简单，因此更容易解开。此外，我们希望，在蠕虫中可用的强大遗传工具将允许快速阐明新的途径，其与哺乳动物行为的相关性随后可以进行测试。我们广泛的长期目标是在分子水平上了解动物是如何调节食物摄入的。我们未来五年的目标是研究控制饱腹感的细胞和分子机制。我们将检验以下假设：1。ASI感觉神经元的活动表明营养状况良好，并引起饱腹感反应。2. ASI的作用是由肽和蛋白质激素的释放介导的，包括胰岛素样肽和tgf -2样肽DAF-7。3. 饱腹感激素基因的表达随着营养状况的改善而增加。4. 饱腹激素作用于下游神经元改变行为。5. 环GMP （cGMP）激活ASI和下游神经元中cGMP依赖性蛋白激酶（PKG）产生饱腹感。目的1。确定饱腹感信号机制（假设1、4、5）。确定单个蠕虫饱腹行为的时间过程。结合激光显微手术，通过表达来自神经元特异性启动子的转基因，确定胰岛素、TGF-2和cGMP通路中信号和受体基因的作用位点和时间（假设2、4和5）。通过上位性研究确定信号作用的顺序，测量过表达和功能获得突变在功能丧失突变背景下的影响。目标2。寻找转录与饱腹感相关的肽和蛋白激素基因（假设2、3）。利用微阵列技术和定量RT-PCR技术，找到受饥饿和再喂养、cGMP和PKG调控转录的肽基因，突变或敲低这些基因的表达，确定对饱腹行为的影响。筛选饱足性静止缺陷突变体，并通过全基因组测序鉴定突变基因。目标3。测量突触活性和ASI肽的释放（假设1,2）。建立突触囊泡pH传感器synaptophorin光漂白后荧光恢复测量突触活性的方法。开发测量神经元荧光肽释放的方法。使用这些方法来确定ASI活性和肽释放如何响应诱导饱腹感的条件。

项目成果

Falling asleep after a big meal: Neuronal regulation of satiety.

• DOI: 10.4161/worm.27938
• 发表时间: 2014
• 期刊: Worm
• 作者: Gallagher T;You YJ
• 通讯作者: You YJ

ASI regulates satiety quiescence in C. elegans.

• DOI: 10.1523/jneurosci.4493-12.2013
• 发表时间: 2013-06-05
• 期刊: The Journal of neuroscience : the official journal of the Society for Neuroscience
• 作者: Gallagher T;Kim J;Oldenbroek M;Kerr R;You YJ
• 通讯作者: You YJ