If severed, nerves outside the brain and spinal cord can reconnect and resume functioning. Unexpectedly, the molecular mechanism behind this remarkable ability turns out to involve fibroblasts — a type of cell that helps with wound repair.

Credit: ELSEVIER

Alison Lloyd at University College London and her colleagues used fluorescence microscopy to observe how cut nerves mend themselves in rats. They observed fibroblasts at the site of injury make contact with Schwann cells, which surround and protect neurons. Signalling between the two cell types prompted the Schwann cells to clump into tiny cords that guide the regrowth of neurons across the wound (pictured). This response, the authors found, is mediated by a protein called SOX2, which is also involved in reprogramming cells to a stem-cell-like state.

Cell 143, 145–155 (2010)