Enzyme found essential for nerve growth

BOSTON, Oct. 27 (UPI) -- U.S. medical researchers say they've determined an enzyme known as Mst3b is essential for regenerating damaged axons, or nerve fibers, in an animal model.

The scientists at Children's Hospital Boston said their discovery could lead to new treatments for human brain and spinal cord injuries in both the peripheral and central nervous systems.

Led by Nina Irwin and Larry Benowitz, the scientists discovered Mst3b appears to be a master regulator of a cell-signaling pathway controlling axon growth. Mst3b, a protein kinase, in turn activates signals that switch on the genes necessary for axons to grow.

Working with live rats whose optic nerve was damaged -- a common model of central-nervous-system injury -- the researchers said they showed that in the absence of Mst3b, axons show very little regeneration, even in the presence of factors known to enhance axon growth.

"All the growth factors we've tested -- oncomodulin, inosine, brain-derived neurotropic factor, nerve growth factor -- act through Mst3b," Benowitz said. "In fact, activating Mst3b by itself is enough to cause growth even if there are no growth factors around. In terms of basic understanding of nerve cells, this is a very exciting finding."

The research appears in the early online edition of the journal Nature Neuroscience.