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: 10429604
• 负责人: Chih-Ying Su
• 金额: $ 19.75万
• 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 2023-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10429604
• 关键词: Afferent Neurons; Agriculture; Behavior; Calcium; Calcium Signaling; Calcium Spikes; Characteristics; Clustered Regularly Interspaced Short Palindromic Repeats; Culicidae; Data; Data Set; Dendrites; Dengue; Disease; Disease Vectors; 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; Olfactory tract; Phase; Property; Receptor Activation; Research; Sensory; Signal Transduction; Smell Perception; Surveys; Techniques; Technology; Testing; West Nile Fever; base; design; dosage; extracellular; falls; fluorescence imaging; genome editing; in vivo; in vivo calcium imaging; insect disease vector; nanoscale; neuronal cell body; response; tool; vector

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.

项目摘要/摘要 该项目的目的是确定气味引起的钙荧光信号与 跨形态上独特类型的绝缘嗅觉受体神经元（ORNS）的尖峰反应。百万 每年通过破坏昆虫传播的疾病（例如疟疾，登革热和西尼罗河）来威胁生命的威胁 发烧 - 由媒介传播，这些向量严重依赖他们的嗅觉寻求宿主。 相应地，越来越多的努力致力于更好地理解隔热嗅觉以开发工具和 干扰寻求宿主行为的策略。随着CRISPR基因组编辑技术的冒险 广泛的昆虫，体内钙成像已成为识别反应的ORN的首选方法 托管气味。但是，钙诱导的荧光信号可能难以解释，因为反应 放大器和动态范围不仅取决于受体激活程度，还取决于 神经元的固有电子特性在神经元类型中可能变化。例如，10％ 荧光信号的增加可能对应于一个高频，近饱和的尖峰响应。 ORN类型，但可以代表另一个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，必须了解峰值钙关系 与单个神经元类型相关。为了实现这一目标，该提议利用了强大的遗传 果蝇的工具包和可拖动的嗅觉系统。与其他绝缘物种类似，果蝇是 根据封装其感觉树突的感觉类型的形态类别分类。 每个感觉符号通常包含2到四个ORN，它们暴露了独特的细胞外尖峰放大器 反映分隔神经元之间的尺寸差异。考虑到电子特性 感觉神经元受其形态和形态特征的影响，任何此类差异 ORN形态类型可能会影响其峰值钙的关系。总体假设 - 气味引起的尖峰和钙反应关系在独特的ORN形态类型中各不相同 - 将会 通过同时进行体内反式荧光成像和单感电生理学测试 记录。在此提案中，AIM 1将确定钙响应动态范围和尖峰荧光 代表所有形态学类别的选择ORN中的关系。 AIM 2将重点介绍 通常存在独特的形态特征的隔室化ORN。成功执行 提案将产生丰富的数据集，以促进对钙诱导的荧光信号的有意义解释 从果蝇类型中记录。重要的是，该信息应推广到其他 昆虫，包括疾病媒介和农业害虫，因为这些Orn形态学阶层在整个环境中发现 昆虫物种。此外，这项系统的调查将为以后的研究奠定基础 感觉神经元钙反应的机械基础。