Mermet-Joret Noëmie, Moreno Andrea, Zbela Agnieszka, Nazari Milad, Ellendersen Bárður Eyjólfsson, Baro Raquel Comaposada, Krauth Nathalie, von Philipsborn Anne, Sørensen Andreas Toft, Piriz Joaquin, Lin John Yu-Luen, Nabavi Sadegh
DANDRITE, The Danish Research Institute of Translational Neuroscience, Aarhus, Denmark.
Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
Elife. 2025 May 13;12:RP90327. doi: 10.7554/eLife.90327.
A well-known phenomenon in the optogenetic toolbox is that all light-gated ion channels, including red-shifted channelrhodopsins (ChRs), are activated by blue light, whereas blue-shifted ChRs are minimally responsive to longer wavelengths. Here, we took advantage of this feature to create a system which allows high-frequency activation of neurons with pulses of red light, while permitting the suppression of action potentials (APs) with millisecond precision by blue light. We achieved this by pairing an ultrafast red-shifted ChR with a blue light-sensitive anion channel of appropriately matching kinetics. This required screening several anion-selective ChRs, followed by a model-based mutagenesis strategy to optimize their kinetics and light spectra. Slice electrophysiology in the hippocampus as well as behavioral inspection of vibrissa movement demonstrate a minimal excitation from blue light. Of significant potential value, in contrast to existing tools, the system we introduce here allows high-frequency optogenetic excitation of neurons with red light, while blue light suppression of APs is confined within the duration of the light pulse.
光遗传学工具库中一个众所周知的现象是，所有光门控离子通道，包括红移视紫红质通道（ChRs），都由蓝光激活，而蓝移ChRs对较长波长的光反应极小。在此，我们利用这一特性创建了一个系统，该系统允许用红光脉冲对神经元进行高频激活，同时允许用蓝光以毫秒精度抑制动作电位（APs）。我们通过将超快红移ChR与动力学适当匹配的蓝光敏感阴离子通道配对来实现这一点。这需要筛选几种阴离子选择性ChRs，随后采用基于模型的诱变策略来优化它们的动力学和光谱。海马体切片电生理学以及触须运动的行为检查表明蓝光产生的兴奋极小。与现有工具相比，我们在此介绍的系统具有重大潜在价值，它允许用红光对神经元进行高频光遗传学兴奋，而蓝光对APs的抑制局限于光脉冲持续时间内。
