Ageing has negative consequences for all the cells and organs in our bodies. Our brains are no exception. Neurons in the developing brain form circuits that can adapt to change and regenerate in response to injury. These capacities have long been known1 to diminish over time, but the molecular shifts that underlie this deterioration have remained mysterious. Lu et al. show in a paper in Nature that neurons of the eye can be programmed to revert to a youthful state in which they reacquire their ability to resist injury and to regenerate.
Excitingly, Lu and colleagues showed that they could induce OSK expression at different time points — even after axon injury — and still improve RGC survival and regeneration. These effects were not limited to optic-nerve injury; OSK expression also effectively reversed RGC and vision loss in a mouse model of glaucoma (the most common cause of human blindness). Expression of OSK in RGCs after axon and vision loss (but before the RGCs died) fully restored vision in these animals. The same was true for wild-type old mice: OSK allowed old mice to regain youthful eyesight.
The effects of OSK in people remain to be tested, but the existing results suggest that OSK is likely to reprogram brain neurons across species.