John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Forvie Site, Robinson Way, Cambridge, UK.
School of Medical Sciences and Save Sight Institute, Charles Perkins Centre, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.
Eye (Lond). 2024 Jul;38(10):1802-1809. doi: 10.1038/s41433-024-03025-0. Epub 2024 Mar 27.
Programmed axon death is a druggable pathway of axon degeneration that has garnered considerable interest from pharmaceutical companies as a promising therapeutic target for various neurodegenerative disorders. In this review, we highlight mechanisms through which this pathway is activated in the retina and optic nerve, and discuss its potential significance for developing therapies for eye disorders and beyond. At the core of programmed axon death are two enzymes, NMNAT2 and SARM1, with pivotal roles in NAD metabolism. Extensive preclinical data in disease models consistently demonstrate remarkable, and in some instances, complete and enduring neuroprotection when this mechanism is targeted. Findings from animal studies are now being substantiated by genetic human data, propelling the field rapidly toward clinical translation. As we approach the clinical phase, the selection of suitable disorders for initial clinical trials targeting programmed axon death becomes crucial for their success. We delve into the multifaceted roles of programmed axon death and NAD metabolism in retinal and optic nerve disorders. We discuss the role of SARM1 beyond axon degeneration, including its potential involvement in neuronal soma death and photoreceptor degeneration. We also discuss genetic human data and environmental triggers of programmed axon death. Lastly, we touch upon potential therapeutic approaches targeting NMNATs and SARM1, as well as the nicotinamide trials for glaucoma. The extensive literature linking programmed axon death to eye disorders, along with the eye's suitability for drug delivery and visual assessments, makes retinal and optic nerve disorders strong contenders for early clinical trials targeting programmed axon death.
程序性轴突死亡是一种可药物干预的轴突退化途径，已经引起了制药公司的极大兴趣，被认为是治疗各种神经退行性疾病的有前途的治疗靶点。在这篇综述中，我们强调了该途径在视网膜和视神经中被激活的机制，并讨论了其在开发眼部疾病和其他疾病治疗方法方面的潜在意义。程序性轴突死亡的核心是两种酶，即 NMNAT2 和 SARM1，它们在 NAD 代谢中起着关键作用。在疾病模型中的广泛临床前数据一致表明，当靶向该机制时，可显著保护神经，在某些情况下，完全和持久地保护神经。来自动物研究的发现现在得到了人类遗传数据的证实，使该领域迅速向临床转化推进。随着我们进入临床阶段，选择适合针对程序性轴突死亡的初始临床试验的疾病变得至关重要，以确保其成功。我们深入探讨了程序性轴突死亡和 NAD 代谢在视网膜和视神经疾病中的多方面作用。我们讨论了 SARM1 在轴突退化之外的作用，包括其在神经元体死亡和光感受器退化中的潜在作用。我们还讨论了程序性轴突死亡的遗传人类数据和环境触发因素。最后，我们探讨了针对 NMNATs 和 SARM1 的潜在治疗方法，以及用于青光眼的烟酰胺试验。大量文献将程序性轴突死亡与眼部疾病联系起来，再加上眼睛适合药物输送和视觉评估，这使得视网膜和视神经疾病成为针对程序性轴突死亡的早期临床试验的强有力候选者。
