Fong Victoria C, Le Beatrice M, Stefanov Antonia, Lee Vivian, Park Seohyun, Sivakumar Adithya, Spatny Sabrina, Visel Meike, Taylor W Rowland, Brohawn Stephen G, Flannery John G
Herbert Wertheim School of Optometry and Vision Science, The University of California, Berkeley, CA, USA.
Helen Wills Neuroscience Institute, The University of California, Berkeley, CA, USA.
Sci Rep. 2025 Jul 1;15(1):21204. doi: 10.1038/s41598-025-04286-9.
Optogenetic gene therapy is a promising mutation-independent treatment that aims to restore visual perception in patients blinded by retinal diseases that cause photoreceptor degeneration. Still, low sensitivity or slow kinetics of currently utilized optogenetic proteins limit the efficacy of such approaches. Here, we evaluated the therapeutic potential of three channelrhodopsin variants: ChRmine, from the algae Rhodomonas lens, ChRmine-T119A, a faster-closing ChRmine variant, and ChroME2s, a second-generation Chronos-based opsin.We expressed these opsins in retinal ganglion cells of rd1 mice, a model of severe retinal degeneration. Single cell electrophysiology demonstrates opsin's large sensitivity to a range of light intensities as well as opsin-expressing retinal ganglion cells generated action potentials in response to light stimulation. Behavioral tests showed ChRmine-T119A's efficacy at 360 lux compared to unmodified ChRmine and ChroME2s. ChRmine and ChroME2s did restore light perception at higher light intensities. Additionally, our dose-response study with ChRmine-T119A revealed that lower viral titers were more effective at restoring light sensitivity. Our study demonstrates that these ChRmine- and ChroME-based opsins can enhance vision in late-stage blinding diseases.
光遗传学基因疗法是一种很有前景的不依赖于突变的治疗方法，旨在恢复因导致光感受器退化的视网膜疾病而失明的患者的视觉感知。然而，目前使用的光遗传学蛋白的低敏感性或缓慢动力学限制了此类方法的疗效。在此，我们评估了三种通道视紫红质变体的治疗潜力：来自莱茵衣藻的ChRmine、关闭速度更快的ChRmine变体ChRmine-T119A以及基于第二代Chronos的视蛋白ChroME2s。我们在严重视网膜退化模型rd1小鼠的视网膜神经节细胞中表达了这些视蛋白。单细胞电生理学表明视蛋白对一系列光强度具有高敏感性，并且表达视蛋白的视网膜神经节细胞在光刺激下产生动作电位。行为测试显示，与未修饰的ChRmine和ChroME2s相比，ChRmine-T119A在360勒克斯的光照强度下具有疗效。ChRmine和ChroME2s在更高的光照强度下确实恢复了光感知。此外，我们对ChRmine-T119A的剂量反应研究表明，较低的病毒滴度在恢复光敏感性方面更有效。我们的研究表明，这些基于ChRmine和ChroME的视蛋白可以增强晚期致盲疾病中的视力。
