Starburst amacrine cells amplify optogenetic visual restoration through gap junctions

<b>Ectopic induction of optogenetic actuators, such as channelrhodopsin, is a promising approach to restore vision in the degenerating retina. However, the cell type-specific response of ectopic photoreception has not been well understood. It is not easy to obtain efficient gene expression in a specifically targeted cell population by a transgenic approach. In the present study, we established retinal ganglion cell (RGC)- and amacrine cell gene induction in a murine model with high efficiency using an improved tetracycline transactivator-operator bipartite system (KENGE-tet system). To investigate the cell type-specific visual restoration effect, we expressed the channel rhodopsin gene into RGCs and amacrine cells using this system. Then, enhancement of the visual restoration effect was observed by gene transfer not only to RGCs but also to starburst amacrine cells. It was suggested that photoresponse from amacrine cells enhanced the maintained response of ganglion cells and furthered the visual restoration effect.</b>

异位诱导光遗传效应因子（optogenetic actuators），例如通道视紫红质（Channelrhodopsin），是修复退行性视网膜病变患者视力的极具潜力的策略。然而，目前学界对异位光感受的细胞类型特异性响应机制仍不甚明晰。采用转基因技术在特定靶向细胞群中实现高效基因表达存在较大挑战。本研究中，我们借助改良的四环素反式激活因子-操纵子双元表达系统（KENGE-tet系统），在小鼠模型中实现了视网膜神经节细胞（RGC）与无长突细胞的高效基因诱导。为探究细胞类型特异性视觉修复效应，我们通过该系统将通道视紫红质基因分别导入RGC与无长突细胞中。实验结果显示，不仅向RGC导入基因，同时向星爆状无长突细胞导入基因时，均可观察到视觉修复效应的显著增强。研究表明，无长突细胞产生的光响应可强化神经节细胞的持续响应，进而进一步提升视觉修复效果。