Worms learning while intoxicated: determining the molecular mechanism and neuronal circuitry required for state dependent learning in Caenorhabditis elegans

蠕虫在醉酒时学习：确定秀丽隐杆线虫状态依赖性学习所需的分子机制和神经元回路

• 批准号: 10269897
• 负责人: Jonathan Houghton Lindsay
• 金额: $ 5.95万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-30 至 2022-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10269897
• 关键词: Ablation; Affect; Alcohol dependence; Alcoholic Intoxication; Alcohols; Alleles; Animal Model; Animals; Behavior; Behavioral; Behavioral Assay; Binding; Caenorhabditis elegans; Caffeine; Cells; Chromosome Mapping; Code; Conflict (Psychology); Coupled; Coupling; Data; Dependence; Dopamine; Ethanol; Exhibits; Exposure to; Felis catus; Genes; Genetic; Genetic Models; Genetic Screening; Genomics; Glutamates; Goals; Impairment; Learning; Left; Link; Mammals; Maps; Mediating; Memory; Modeling; Molecular; Moods; Mutation; Names; Nervous system structure; Neurobiology; Neurons; Neurotransmitters; Nicotine; Octopamine; Odors; Olfactory Learning; Olfactory Pathways; Organism; Pain; Peptide Signal Sequences; Positioning Attribute; Prevention; Process; Receptor Protein-Tyrosine Kinases; Sensory; Signal Transduction; Stimulus; Study models; Testing; Work; X Chromosome; addiction; alcohol effect; alcohol exposure; alcohol misuse; alcoholism therapy; arm; behavioral response; cost estimate; drug of abuse; forward genetics; gamma-Aminobutyric Acid; genetic approach; genetic variant; genome sequencing; human subject; learned behavior; long term memory; memory process; memory recall; mutant; neural circuit; neuronal circuitry; neurotransmission; nicotine exposure; novel; olfactory stimulus; sobriety; societal costs; substance use; whole genome

Abstract Links between the neurobiology of learning and the neurobiology of addiction have been well documented. For instance, human subjects recall memories more readily while intoxicated if the memory was acquired in an intoxicated state. This is known as state dependent learning (SDL). SDL has been demonstrated in a wide variety of organisms, but little is known of the molecular mechanisms and neurocircuitry associated with SDL. In Caenorhabditis elegans (C. elegans), SDL is demonstrated by coupling the intoxicating effects of ethanol with a specific learned behavior known as olfactory adaptation; animals recall their exposure while intoxicated to an olfactory stimulus better if they are tested while intoxicated. C. elegans are an optimal model for studying the molecular underpinnings of SDL, as they have a simple 302-neuron nervous system with invariant neurocircuitry from animal to animal. The neurotransmitter dopamine is required for SDL, and animals with mutations in dopamine synthesizing genes, cat-1 and cat-2, do not learn state-dependently. These results suggest learning while intoxicated activates distinct SDL neurocircuitry that innervate and alter signaling of olfactory adaptation neurons. The ultimate goal of this work is to discover the circuit required for state dependency, and how this is regulated at the molecular level. Preliminary results show that a signaling peptide, hen-1, and a receptor tyrosine kinase, scd-2, are required for SDL. The hen-1 expressing neuron ASE-R is also required for SDL. The ASE-L neuron, which expresses almost all of the same genes as ASE-R with the exception of hen-1, is not required for SDL. In specific aim 1 I will test the sufficiency of hen-1 and scd-2 expression in ASE-R and AIA neurons respectively. Other preliminary results show octopamine deficient worms do not show SDL. The only neurons that release octopamine are RIC neurons. I will test constructs lacking the RIC neuron via genetic ablation for SDL. I have also demonstrated that SDL emerges from exposure to nicotine during olfactory learning in C. elegans. In specific aim 2 I will test for similarities in molecular mechanisms and neurocircuitry between SDL that emerge from ethanol and nicotine. I will also determine if SDL emerges in worms exposed to caffeine. Previously, a forward genetic screen was performed to find animals that are incapable of learning state-dependently during ethanol intoxication. A mutation, dubbed sdl-1, was isolated through selective screens. In specific aim 3 I will use genetic mapping and genomic sequencing to determine the molecular identity of sdl-1 and determine how the gene containing this mutation might promote SDL. Here, I hypothesize that SDL induced by ethanol intoxication has a distinct circuit that inputs onto olfactory adaptation neurocircuitry. My aims identify the molecular mechanism and neurocircuitry of this behavior by, 1) investigating hen-1/scd-2 and octopaminergic signals, 2) using other substances that may induce SDL, and 3) utilizing gene mapping to identify a novel gene associated with SDL.

摘要 学习的神经生物学和成瘾的神经生物学之间的联系已经得到了很好的证明。为 例如，人类受试者在醉酒时更容易回忆起记忆，如果记忆是在一个 醉酒状态这被称为状态相关学习（SDL）。SDL已在广泛的 多种生物，但很少有人知道的分子机制和神经回路与SDL。 在秀丽隐杆线虫（C. habditis elegans）中，elegans），SDL是通过耦合乙醇的致醉作用来证明的 具有一种特殊的学习行为，称为嗅觉适应;动物在醉酒时回忆它们的暴露 对嗅觉刺激的反应更好。C.线虫是研究 SDL的分子基础，因为它们有一个简单的302神经元神经系统， 从动物到动物的神经回路神经递质多巴胺是SDL所必需的， 多巴胺合成基因cat-1和cat-2的突变不依赖于状态学习。这些结果 暗示中毒时的学习激活了不同的SDL神经回路， 嗅觉适应神经元这项工作的最终目标是发现状态所需的电路 依赖性，以及如何在分子水平上进行调节。初步结果显示，一种信号肽， hen-1和受体酪氨酸激酶scd-2是SDL所必需的。表达hen-1的神经元ASE-R是 SDL也需要。ASE-L神经元表达几乎所有与ASE-R相同的基因， 除了hen-1，SDL不需要。在具体目标1中，我将测试hen-1和scd-2的充分性 ASE-R和AIA神经元表达。其他初步结果显示章鱼胺缺乏 蠕虫不显示SDL。唯一释放章鱼胺的神经元是RIC神经元。我将测试结构 通过基因切除术来治疗SDL，我还演示了SDL是从 在C.优美的在具体目标2中，我将测试 酒精和尼古丁产生的SDL之间的分子机制和神经回路。我也会 确定SDL是否出现在接触咖啡因的蠕虫中。此前， 去寻找那些在酒精中毒时无法进行状态依赖学习的动物。一种变异， 通过选择性筛选分离到sdl-1。在具体目标3中，我将使用遗传作图和基因组 测序以确定SDL-1的分子身份并确定含有该突变的基因如何 可能会促进SDL。在这里，我假设酒精中毒引起的SDL有一个独特的回路， 输入到嗅觉适应神经回路。我的目标是确定分子机制， 这种行为的神经回路，1）研究hen-1/scd-2和章鱼胺能信号，2）使用其他 可诱导SDL的物质，和3）利用基因作图来鉴定与SDL相关的新基因。