Genetic Switch Offers New Clue to Rebuilding Nerve Connections After Stroke and Spinal Injury

Scientists at Brown University have identified a previously unrecognised genetic “switch” that helps developing nerve fibres navigate through the nervous system, a discovery that could eventually inform attempts to repair connections damaged by spinal cord injury or stroke. Researchers studying commissural neurons found that growing axons — the long fibres that carry signals between nerve cells — do not rely only on instructions from their tips, as scientists had traditionally thought. Instead, as axons pass important checkpoints during development, the neuron changes the activity of entire groups of genes in its cell body, causing different guidance molecules to appear and direct the axon toward its next destination. Using single-cell RNA sequencing, the team analysed gene activity across more than 12,000 developing neurons and created what researchers describe as a genetic atlas of spinal-cord development. The finding could be important because scientists can already encourage some damaged axons to regrow, but directing those fibres back to the correct targets remains a major challenge. Researchers hope that understanding which genes guide normal nerve development may eventually reveal ways to reactivate similar programmes following neurological injury. The work, published in Proceedings of the National Academy of Sciences, remains early-stage laboratory research and does not yet provide a treatment for paralysis or stroke, but it offers scientists a new biological roadmap for investigating how damaged neural connections might one day be rebuilt.