Interrogating Biophysical Mechanisms of Magnetogenetic Cell Stimulation at Radio Frequencies

摘要 磁遗传学是最近提出的一种利用电磁场刺激细胞的方法。合而为一 方法，应用射频(RF)电磁场来刺激膜通道蛋白 作为附着在铁蛋白上的TRPV1和TRPV4。这一概念非常吸引人，因为它使无线神经 不受穿透深度或侵入性手术要求的刺激。如果成功，射频- 基于磁遗传学可以为大规模神经刺激提供一种非侵入性的方法，这种方法可以达到 在大脑中的任何位置并实现细胞特异性。此功能克服了其他 电刺激和光遗传学等刺激在空间上受到限制的技术。然而， 虽然已经有几个关于磁生效应的实验证据的独立报道 射频波，这种效应的物理和神经生物学基础仍然不清楚和有争议。 已报道的实验只在几个选定的频率和幅度下进行，而 响应大多是基于下游生理效应间接测量的。该计划的目标是 拟议的项目是系统地描述、建模和验证神经生物学和细胞反应 在RF刺激下，表达铁蛋白连接的TRPV1和TRPV4通道的神经元。具体来说，我们的目标是 为了描述这些磁发生通道的特征：1)神经元对电和化学刺激的反应 以及在广泛的频率和幅度范围内的射频刺激；2)对射频的温度响应 蛋白质、细胞膜和细胞水平的刺激；3)细胞代谢过程对RF的影响 刺激。我们将系统地评估两个新的潜在机制的工作假说。如果 成功后，该项目将表征细胞对射频刺激的反应，量化激活阈值 和安全限度，建立标准方案，并阐明这种报告的射频的生物物理基础- 基于磁生现象。它将解决推进这项技术的一个根本挑战，并 指导更合理的设计和技术的改进。理解初始状态的机制 关于磁遗传学的报道将是对目前神经刺激整体的重大补充。 电刺激和光遗传学等技术有助于大脑的一个中心目标 主动开发适用于控制特定细胞的新的和改进的扰动技术 调节中枢神经系统功能的类型和回路。

Abstract Magnetogenetics is a recently proposed method for stimulating cells using electromagnetic fields. In one approach, radio-frequency (RF) electromagnetic fields are applied to stimulate membrane channel proteins such as TRPV1 and TRPV4 that are attached to ferritins. The concept is highly attractive as it enables wireless neural stimulation without limitation on penetration depth or the requirement of invasive surgeries. If successful, RF- based magnetogenetics can provide a non-invasive approach for large-scale neural stimulation that can reach anywhere in the brain and achieve cellular specificity. This capability overcomes a significant limitation in other techniques such as electrical stimulation and optogenetics where stimulation is spatially restricted. However, while there have been several independent reports of experimental evidences for magnetogenetic effects using RF waves, the physical and neurobiological underpinnings of such effects remain unclear and controversial. Reported experiments have been conducted only in a few selected frequencies and amplitudes and the responses were mostly measured indirectly based on downstream physiological effects. The objective of the proposed project is to systematically characterize, model and validate the neurobiological and cellular responses upon RF stimulation in neurons expressing ferritin-attached TRPV1 and TRPV4 channels. Specifically, we aim to characterize these magnetogenetic channels of their: 1) neuronal responses to electrical and chemical stimuli and to RF stimulation over a wide range of frequencies and amplitudes; 2) temperature responses to RF stimulation at the protein, cytoplasmic membrane and cellular level; 3) cellular metabolic processes upon RF stimulation. We will systematically evaluate two novel working hypotheses of the underlying mechanisms. If successful, the project will characterize the cellular responses to RF stimulation, quantify activation thresholds and safety limits, establish standard protocols and elucidate the biophysical underpinnings of this reported RF- based magnetogenetic phenomenon. It would resolve a fundamental challenge in advancing this technology and guide a more rationale design and improvement of the techniques. Understanding the mechanisms of the initial reports of magnetogenetics would be a significant addition to the present ensemble of neuro-stimulation technologies such as electrical stimulation and optogenetics and contribute to one central goal of the BRAIN Initiative that is to develop new and improved perturbation technologies suitable for controlling specified cell types and circuits to modulate function in the central nervous system.