Fluorescent biosensors for imaging neurotransmitters: observing synapses in actio

用于神经递质成像的荧光生物传感器：观察活动中的突触

基本信息

批准号：
8758411
负责人：
Lin Tian
金额：
$ 234.98万
依托单位：
UNIVERSITY OF CALIFORNIA AT DAVIS
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-09-19 至 2019-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8758411
关键词：
Address Aminobutyric Acids Animals Area Autistic Disorder Behavior Behavior Control Biosensor Brain Calcium Communication Complex Computer Simulation Epilepsy Equilibrium Event Excitatory Synapse Fluorescence Future Glutamates Goals Image Imaging Device Industry Inhibitory Synapse Learning Link Logic Measures Medicine Memory Mental Depression Methods Microscope Microscopy Monitor Neurons Neurosciences Neurotransmitters Optics Outcome Population Proteins Reporting Research Resolution Sampling Schizophrenia Signal Transduction Structure Synapses Synaptic Transmission Time Tissues addiction awake base calcium indicator design drug discovery gamma-Aminobutyric Acid information processing interest nervous system disorder neural circuit neurotransmitter release novel optical sensor public health relevance relating to nervous system sensor spatiotemporal tool two-photon

项目摘要

DESCRIPTION (provided by applicant): One of the greatest challenges in neuroscience is to decipher the logic of the neural circuitry and link it to learning, memory, and behavior. Neural circuitry is a dynamic network that incorporates neuronal activity at a variety of spatial and temporal scales. Therefore, analysis of neural circuitry demands broad and dense sampling of neuronal activity across time and brain structures. Recent breakthroughs in modern microscope and protein based fluorescence sensors have brought this goal within reach. For example, application of genetically encoded calcium indicators, such as GCaMP3, combined with two-photon microscopy, has facilitated the large- scale recording of neural activity in a genetically-identified population at multiple time scales in awake, behaving animals. These applications have greatly advanced our understanding of the dynamics of neural circuitry and its control of behavior-a critical first step toward understanding complex brain function. Building upon the momentum of calcium imaging, the immediate need to accelerate future analyses of the dynamics of neural circuitry is to develop a broader suite of optical sensors to expand the kinds of neuronal activity that can be measured. One particular area of interest is synaptic transmission, a critical event of information processing in the brain that is difficult to access wth the optical tools currently available. There are two key questions that need to be addressed before we can develop a dynamic picture of synaptic transmission. First, we must understand how synaptic connectivity is linked to its activity; second, we must determine how different types of neurotransmitters balance with each other in a defined circuitry. Therefore, I plan to develop two classes of novel protein-based fluorescent sensors, using methods that have emerged only recently, to enable monitoring of synaptic transmission from these two different angles. For the first project outlined in this proposal, I will develop sensors specially designed for simultaneous recording of both synaptic activity and connectivity. Recently, I have been involved in developing a genetically-encoded neurotransmitter sensor (iGluSnfr) to directly measure released glutamate. This sensor, for the first time, offers the potential for monitoring excitatory synaptic activity in time and space. However, its ability to report synaptic connectivity, a piece f important information stored in the neural circuitry, is currently lacking. Therefore, I will develp strategies to split iGluSnfr into pre- and post-synaptic components. This designer sensor will permit simultaneous recording of both synaptic activity and connectivity, thus providing a way to find the synapses that are activity-dependent in a defined circuitry. For the second project outlined in this proposal, I will develop a new sensor to direct monitor inhibitory communication between neurons at synapses. It is known that based on the kind of neurotransmitters released, the communication between neurons can be either excitatory or inhibitory. Imbalanced excitatory and inhibitory synapses in specific neural circuitry have been implicated in an array of neurological disorders, including depression, addiction, autism, schizophrenia and epilepsy. Yet, optical sensors for directly monitoring inhibitory signals with needed spatiotemporal resolution are still missing. I will leverage computational modeling to redesign iGluSnFr to sense inhibitory neurotransmitters, such as ?-aminobutyric acid (GABA). Similarly, the splitting strategy to be developed in project one will be further utilized to split the GABA sensor into pre- and post-synaptic components. Taken together, a successful outcome of the proposed research would provide much needed imaging tools to enable neuroscientists to obtain a comprehensive view of both excitatory and inhibitory synapses in action at the cellular, tissue, and whole-animal level.

描述（由申请人提供）：神经科学中最大的挑战之一是破译神经回路的逻辑并将其与学习、记忆和行为联系起来。神经回路是一个动态网络，包含各种空间和时间尺度的神经元活动。因此，神经回路的分析需要对跨时间和大脑结构的神经元活动进行广泛而密集的采样。现代显微镜和基于蛋白质的荧光传感器的最新突破使这一目标触手可及。例如，应用基因编码的钙指示剂（例如 GCaMP3）与双光子显微镜相结合，有助于在清醒、行为动物的多个时间尺度上大规模记录基因识别群体的神经活动。这些应用极大地促进了我们对神经回路动力学及其行为控制的理解——这是理解复杂大脑功能的关键的第一步。在钙成像的发展势头的基础上，加速未来神经回路动力学分析的迫切需要是开发更广泛的光学传感器，以扩大可测量的神经元活动的种类。一个特别令人感兴趣的领域是突触传递，这是大脑中信息处理的关键事件，目前可用的光学工具很难访问它。在我们绘制突触传递的动态图之前，需要解决两个关键问题。首先，我们必须了解突触连接如何与其活动相关联；其次，我们必须确定不同类型的神经递质在定义的电路中如何相互平衡。因此，我计划使用最近才出现的方法开发两类新型基于蛋白质的荧光传感器，以便能够从这两个不同的角度监测突触传递。对于本提案中概述的第一个项目，我将开发专门为同步设计的传感器记录突触活动和连接。最近，我参与开发了一种基因编码神经递质传感器（iGluSnfr）来直接测量释放的谷氨酸。该传感器首次提供了监测兴奋性的潜力时间和空间上的突触活动。然而，它目前缺乏报告突触连接（神经回路中存储的重要信息）的能力。因此，我将制定策略将 iGluSnfr 分为突触前和突触后成分。该设计传感器将允许同时记录突触活动和连接性，从而提供一种在定义的电路中查找依赖于活动的突触的方法。对于本提案中概述的第二个项目，我将开发一种新的传感器来直接监测突触神经元之间的抑制性通信。众所周知，根据释放的神经递质的类型，神经元之间的通讯可以是兴奋性的，也可以是抑制性的。特定神经回路中兴奋性和抑制性突触的不平衡与一系列神经系统疾病，包括抑郁症、成瘾症、自闭症、精神分裂症和癫痫症。然而，仍然缺少用于直接监测具有所需时空分辨率的抑制信号的光学传感器。我将利用计算模型重新设计 iGluSnFr 来感知抑制性神经递质，例如 γ-氨基丁酸 (GABA)。同样，项目一中开发的拆分策略将进一步利用将 GABA 传感器拆分为突触前和突触后组件。总而言之，拟议研究的成功结果将提供急需的成像工具，使神经科学家能够全面了解细胞、组织和整个动物水平上的兴奋性和抑制性突触的作用。