BRC-BIO: The role of serotonin signaling in autoregulation of axon morphology, connectivity, and behavior in Drosophila

BRC-BIO：血清素信号传导在果蝇轴突形态、连接性和行为自动调节中的作用

• 批准号: 2232510
• 负责人: Douglas Roossien
• 金额: $ 50.3万
• 依托单位: Ball State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-01 至 2026-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2232510&HistoricalAwards=false
• 关键词: BRC; BIO; role; serotonin; signaling

The primary role of the nervous system is to perceive conditions in our surroundings and elicit the appropriate behavioral response. This is controlled by complex neural circuits that are interconnected through long cable-like structures called axons. One important group of axons arises from serotonin-producing brain cells, which integrate with circuits throughout the nervous system to modulate behaviors such as mood, sleep, appetite, and cognition. Ultimately, these behavioral outputs are determined by the precise growth and wiring of axons. Recent work by the PI and others in the field has shown that serotonin-producing brain cells use serotonin itself to help shape its axons during early stages of development. This research will utilize cutting-edge genetic tools available in fruit flies, Drosophila melanogaster, to understand how this molecular mechanism works inside the cells, how it shapes circuits in the brain, and how it impacts behavioral output. The fruit fly nervous system is built with the same basic components, which assemble and direct neural activities as they do in the human nervous system. The knowledge gained will therefore provide insight into how abnormal serotonin exposure during development can lead to behavioral disorders in humans. These studies will provide students with multidisciplinary research experiences in genetics, cellular biology, and neuroscience through paid research positions. By reducing financial barriers to undergraduate research at an institute serving large populations of low-income and first-generation college students, this project advances the NSF mission to grow a diverse STEM workforce.Preliminary in vitro experiments indicate the serotonin receptor 5-HT1A initiates signaling events that autoregulate serotonergic axon outgrowth. The first objective of this project is to determine the intracellular mechanisms 5-HT1A engages using genetic and pharmacological manipulation of candidate serotonin signaling pathways in primary Drosophila serotonergic neurons paired with morphometric analysis of axon outgrowth and live cell imaging of actin dynamics. The second objective of this project is to determine how autoregulation shapes anatomical circuits using a single serotonergic neuron (SP2-1) as a model. This neuron innervates the larval visual system and can be labeled selectively using existing genetic tools, allowing 3D reconstructions of the SP2-1 neuron under various experimental conditions. A novel anterograde trans-synaptic Brainbow labeling approach will be used to ask how changes in serotonin signaling alter connectivity of the SP2-1 neuron. The third objective is to understand how defects in serotonin autoregulation can alter behavioral outputs by manipulating serotonin signaling and correlating changes in SP2-1 morphology to changes in vision-based behaviors. These studies will provide the first molecular mechanism of serotonin autoregulation and its impact on the morphological and functional development of the serotonergic system. This research pipeline will also serve as a foundation for future research including analysis of different cell types and/or circuits, behavioral paradigms, other signaling molecules, and developmental stages.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

神经系统的主要作用是感知我们周围的状况，并引发适当的行为反应。这是由复杂的神经回路控制的，这些神经回路通过被称为轴突的长电缆状结构相互连接。一组重要的轴突来自产生5-羟色胺的脑细胞，它们与整个神经系统的回路相结合，调节情绪、睡眠、食欲和认知等行为。最终，这些行为输出是由轴突的精确生长和连接决定的。PI和该领域的其他人最近的研究表明，在发育的早期阶段，产生5-羟色胺的脑细胞使用5-羟色胺本身来帮助塑造轴突。这项研究将利用果蝇中可用的尖端遗传工具，了解这种分子机制如何在细胞内工作，它如何塑造大脑中的电路，以及它如何影响行为输出。果蝇的神经系统是由与人类神经系统相同的基本组件组成的，这些组件组装和指导神经活动。因此，所获得的知识将为深入了解发育过程中异常的5-羟色胺暴露如何导致人类行为障碍提供洞察力。这些研究将通过付费研究职位为学生提供遗传学、细胞生物学和神经科学方面的多学科研究经验。通过减少为大量低收入和第一代大学生服务的研究所进行本科生研究的资金障碍，该项目推进了NSF培养多样化的STEM工作队伍的使命。初步的体外实验表明，5-HT1A启动信号事件，自动调节5-羟色胺能轴突生长。本项目的第一个目标是通过对果蝇原代5-羟色胺能神经元中候选5-羟色胺信号通路的遗传和药理学操作，结合轴突生长的形态计量分析和肌动蛋白动态的活细胞成像，确定5-HT1A参与的细胞内机制。该项目的第二个目标是确定自动调节如何使用单个5-羟色胺能神经元(SP2-1)作为模型来塑造解剖电路。这种神经元支配幼虫的视觉系统，可以使用现有的遗传工具选择性地进行标记，从而可以在各种实验条件下对SP2-1神经元进行3D重建。一种新的顺行跨突触脑弓标记方法将被用来研究5-羟色胺信号的变化如何改变SP2-1神经元的连接性。第三个目标是了解5-羟色胺自我调节缺陷如何通过操纵5-羟色胺信号并将SP2-1形态的变化与基于视觉的行为的变化相关联来改变行为输出。这些研究将提供5-羟色胺自我调节的第一个分子机制及其对5-羟色胺能系统形态和功能发育的影响。这一研究渠道也将作为未来研究的基础，包括对不同细胞类型和/或电路、行为范式、其他信号分子和发育阶段的分析。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。