Researchers believe they have found a potential way to regenerate nerves by stimulating a gene and said they hope their work in worms may some day help people with spinal cord injuries. The gene is part of a network, or pathway, of four genes that appear to be essential for nerve repair, they reported in the journal Science. “We found a pathway that not only regenerates nerves in the worm, but also exists in humans, and we think it serves the same purpose,” Michael Bastiani of the University of Utah in Salt Lake City, who led the study, said in a statement. Bastiani said the gene could serve as a target for a future drug that could “vastly improve the ability of a neuron to regenerate after injury.” In humans, nerve fibers in the arms and legs can regenerate, but in the brain and spinal cord, they do not. Many teams are working to understand why. Bastiani's team looked to nematode worms for clues. Using an advanced research technique called RNA interference, the team systematically blocked the action of 5,000 worm genes to isolate those important for nerve repair. They found a gene called dlk-1 was essential to the process at every stage of the worm's life. When they used genetic engineering to block this gene network, the worms were unable to repair nerve damage. But when they stimulated the gene – making it more active than normal –worms with damaged nerves recovered much more quickly. Curiously, this network of genes is not used by the nervous system during normal development in the embryo, but it is essential for nerve repair after birth. “Most of us believed that virtually everything we found in regeneration also would be involved in development,” Bastiani said. Bastiani and colleagues noted that to be effective, the dlk-1 gene must be stimulated soon after injury to make a protein that stimulates repair, suggesting there might be “a time window in which you have to activate this pathway.” Many teams have been working on finding ways to block proteins that inhibit nerve repair in adults. Last year, a team at Children's Hospital Boston reported in the journal Science they were able to stimulate nerve regeneration in mice with damaged optic nerves by turning off proteins that keep adult nerve cells from growing. A separate team from the biotechnology firm Genentech Inc was able to stimulate nerve regeneration by blocking chemical signals that create a hostile environment for nerve repair.
