The relationship between spike response and calcium fluorescent signal in insect olfactory receptor neurons

昆虫嗅觉受体神经元尖峰反应与钙荧光信号的关系

• 批准号: 10552644
• 负责人: Chih-Ying Su
• 金额: $ 23.7万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-19 至 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10552644
• 关键词: Afferent Neurons; Agriculture; Behavior; Calcium; Calcium Signaling; Calcium Spikes; Categories; Characteristics; Clustered Regularly Interspaced Short Palindromic Repeats; Culicidae; Data; Data Set; Dedications; Dendrites; Dengue; Disease; Disease Vectors; Disparity; Drosophila genus; Electron Microscopy; Electrophysiology (science); Encapsulated; Exhibits; Fluorescence; Foundations; Frequencies; Future; Genetic; Goals; Image; Individual; Insecta; Malaria; Methods; Morphology; Neurons; Odors; Olfactory Pathways; Olfactory Receptor Neurons; Phase; Property; Receptor Activation; Research; Sensory; Signal Transduction; Smell Perception; Surveys; Techniques; Technology; Testing; West Nile Fever; design; dosage; extracellular; falls; fluorescence imaging; genome editing; in vivo; in vivo calcium imaging; insect disease vector; nanoscale; neuronal cell body; outcome disparities; response; tool; vector transmission

PROJECT SUMMARY/ABSTRACT The goal of this project is to determine the relationships between odor-induced calcium fluorescence signals and spike responses across morphologically distinctive types of insect olfactory receptor neurons (ORNs). Millions of lives are threatened annually by devastating insect-borne diseases—such as malaria, dengue, and West Nile fever—which are transmitted by vectors that heavily rely on their sense of smell for host-seeking. Correspondingly, growing efforts are dedicated to better understanding insect olfaction to develop tools and strategies to interfere with host-seeking behavior. With the advent of CRISPR genome editing technology in a wide range of insects, in vivo calcium imaging has become a method of choice for identifying ORNs that respond to host odors. However, calcium-induced fluorescence signals may be difficult to interpret, because response amplitudes and dynamic ranges are determined not only by the degree of receptor activation, but also by the intrinsic electrotonic property of neurons which can vary markedly across neuronal types. For example, a 10% increase in fluorescence signal may correspond to a high-frequency, near-saturating spike response for one ORN type, but may instead represent a low spike response at the rising phase of the dosage curve for another. In order to accurately interpret calcium imaging data, it is imperative to understand the spike-calcium relationship associated with individual neuronal types. To achieve this goal, this proposal leverages the powerful genetic toolkit and tractable olfactory system of Drosophila. Similar to other insect species, Drosophila ORNs are categorized under morphological classes based on the sensillum types that encapsulate their sensory dendrites. Each sensillum typically contains two to four ORNs, which exhibit distinctive extracellular spike amplitudes that reflect the size differences between compartmentalized neurons. Given that the electrotonic properties of sensory neurons are influenced by their morphological and morphometric features, any such differences across ORN morphological types will likely impact their spike-calcium relationship. The general hypothesis—that the odor-induced spike and calcium response relationship vary across distinctive ORN morphological types—will be tested via simultaneous in vivo trans-cuticle fluorescence imaging and single-sensillum electrophysiological recording. In this proposal, Aim 1 will determine the calcium response dynamic range and spike-fluorescence relationship in select ORNs representing all morphological classes. Aim 2 will focus on the comparison between compartmentalized ORNs which typically exhibit distinctive morphometric features. Successful execution of the proposal will yield a rich dataset to facilitate meaningful interpretation of calcium-induced fluorescence signals recorded from Drosophila ORN types. Importantly, this information is expected to be generalizable to other insects, including disease vectors and agricultural pests, as these ORN morphological classes are found across insect species. Moreover, this systematic survey will lay the foundation for future studies to determine the mechanistic underpinnings of sensory neurons’ calcium responses.

项目概要/摘要 该项目的目标是确定气味诱导的钙荧光信号与 数百万形态独特的昆虫嗅觉受体神经元（ORN）的尖峰反应。 每年 的生命受到毁灭性虫媒疾病的威胁，例如疟疾、登革热和西尼罗河病 发烧——通过严重依赖嗅觉寻找宿主的媒介传播。 相应地，越来越多的努力致力于更好地了解昆虫嗅觉，以开发工具和 随着 CRISPR 基因组编辑技术的出现，干扰宿主寻找行为的策略。 由于昆虫种类繁多，体内钙成像已成为识别响应的 ORN 的首选方法 然而，钙诱导的荧光信号可能难以解释，因为反应。 幅度和动态范围不仅取决于受体激活的程度，还取决于 神经元的固有电紧张特性在神经元类型之间可能存在显着差异，例如 10%。 荧光信号的增加可能对应于一种高频、接近饱和的尖峰响应 ORN 类型，但可能代表另一种剂量曲线上升阶段的低尖峰响应。 为了准确解释钙成像数据，必须了解尖峰-钙关系 为了实现这一目标，该提案利用了强大的遗传功能。 果蝇的工具包和易于处理的嗅觉系统与其他昆虫物种相似，果蝇 ORN 是果蝇的工具包和易处理的嗅觉系统。 根据封装其感觉树突的感器类型分类为形态学类别。 每个感器通常包含两到四个 ORN，它们表现出独特的细胞外尖峰幅度， 考虑到电紧张特性，反映了区室化神经元之间的大小差异。 感觉神经元受到其形态和形态测量特征的影响，任何此类差异 ORN 形态类型可能会影响其尖峰-钙关系。 气味引起的尖峰和钙反应关系因不同的 ORN 形态类型而异 - 将是 通过同时测试的体内跨角质层荧光成像和单感器电生理学 在本提案中，目标 1 将确定钙响应动态范围和尖峰荧光。 目标 2 将重点关注代表所有形态类别的选定 ORN 之间的关系。 分隔的 ORN 通常表现出独特的形态特征。 该提案将产生丰富的数据集，以促进对钙诱导荧光信号的有意义的解释 重要的是，该信息有望推广到其他果蝇 ORN 类型。 昆虫，包括病媒和农业害虫，因为这些 ORN 形态类别遍布各地 此外，这项系统调查将为未来的研究奠定基础，以确定昆虫种类。 感觉神经元钙反应的机制基础。