Genetically-Encoded, Non-Invasive and Wireless Modulation of Calcium Dynamics in Astrocytes With Spatiotemporal Precision and Depth

摘要 星形胶质细胞是大脑中最丰富的细胞类型，长期以来一直被认为主要是被动支持 细胞。在过去的二十年里，利用现代技术的研究揭示了星形胶质细胞的关键作用 在神经元回路组装中，突触的功能和行为。异常的星形细胞功能与 神经精神和神经退行性疾病，以及星形胶质细胞作为新的治疗方法前景光明 提高治疗效果的目标。尽管取得了这些进展，但更深层次的机械理解 星形胶质细胞在神经回路的起因和相关作用及其对行为的贡献仍然是 缺乏。这一认识差距在很大程度上是由于缺乏有效控制星形胶质细胞活动的技术。 具有细胞类型和时间精度。星形胶质细胞的生理特征是其复杂的时空 细胞内和细胞间钙信号的模式对它们与神经元的双向相互作用至关重要。 这个项目的目标是开发一种非侵入性的、无线的和遗传编码的致动器来调节 星形胶质细胞在体内的活性与细胞类型和时间的精确性。我们的方法，称为FeRIC(铁蛋白铁 重分布到离子通道)，结合使用射频(RF)波和离子通道来控制 膜离子渗透性非侵入性和无线。FeRIC技术利用射频波来激活 与内源性细胞铁储存蛋白铁蛋白偶联的膜蛋白。我们的预赛 研究证实了铁离子通道介导的射频刺激调节钙离子活动的可行性。 类似于生理条件下观察到的星形细胞和星形细胞网络。此外， FeRIC介导的星形胶质细胞RF刺激能够诱导神经递质释放和唤起作用 连接的神经元中的电位。我们的目标是开发一套分子工具，并表征它们的能力 调节星形胶质细胞的整体钙信号，2)调节星形胶质细胞的微域钙活动和 3)在体内调节星形胶质细胞-神经元在三部分突触上的相互作用。如果成功，该项目将 开发一种非侵入性和遗传编码的分子工具来调节星形胶质细胞的活动与细胞类型和 时间精确度。我们将阐明这一机制的生物物理基础。该项目将有一个 对星形胶质细胞在健康和疾病中的作用的研究产生广泛的影响。

Abstract Astrocytes are the most abundant cell types in the brain and have long been thought as primarily passive support cells. Studies in the past two decades leveraging modern techniques have revealed crucial roles for astrocytes in neuronal circuit assembly, synaptic function and behavior. Aberrant astrocytic function is implicated in neuropsychiatric and neurodegenerative diseases, and astrocytes hold great promises as novel therapeutic targets for improving treatment efficacy. Despite this progress, a deeper mechanistic understanding of astrocytes' causative and correlative roles in operating neural circuitry and their contribution to behavior is still lacking. This knowledge gap is largely due to the lack of technologies to effectively manipulate astrocyte activity with cell-type and temporal precision. The physiological hallmark of astrocytes is their complex spatiotemporal patterns of intracellular and intercellular calcium signaling crucial to their bidirectional interaction with neurons. The objective of this project is to develop a non-invasive, wireless and genetically encoded actuator to modulate astrocytic activity with cell-type and temporal precision in vivo. Our approach, named FeRIC (Ferritin iron Redistribution to Ion Channels), combines the use of radiofrequency (RF) waves and ion channels to control membrane ion permeability non-invasively and wirelessly. The FeRIC technique utilizes RF waves to activate membrane proteins that are coupled to the endogenous cellular iron storage protein ferritin. Our preliminary studies have demonstrated the feasibility of FeRIC-mediated RF stimulation to modulate calcium activities in astrocytes and astrocytic networks that resembles those observed under physiological conditions. Further, FeRIC-mediated RF stimulation of astrocytes has been able to elicit neurotransmitter release and evoke action potentials in connected neurons. We aim to develop a set of molecular tools and characterize their abilities 1) to modulate global calcium signaling in astrocytes, 2) to modulate microdomain calcium activities in astrocytes and 3) to modulate astrocyte-neuron interactions at the tripartite synapses in vivo. If successful, the project will develop a non-invasive and genetically encoded molecular tool to modulate astrocytic activity with cell-type and temporal precision. We will elucidate the biophysical underpinnings of the mechanism. The project will have a broad impact to the study of the roles of astrocytes in health and disease.