Scientists altered the genes of nematode worms, triggering the fusion of neurons. Photo by Hilliard Lab, Queensland Brain Institute
Aug. 27 (UPI) -- Contrary to a long-held consensus among neuroscientists, neurons can and do fuse, according to a study published Thursday in the journal Proceedings of the National Academy of Sciences.
Until now, most researchers assumed nerve cells remained separate, but scientists at the University of Queensland successfully engineered nematode worms to express fusogens in their neurons, causing their brain cells to fuse together.
Fusogens, molecules that control cell fusion in other types of tissue, are rarely found in the nervous system, except as a result of viral infections or neurological diseases, like sclerosis and schizophrenia.
"We have limited knowledge of the effect of fusogens in neurons, and what happens if neurons fuse together, so we explored these questions in the one millimeter-long nematode worm C. elegans, where we can easily visualize neurons under the microscope and manipulate their genes," Massimo Hilliard, professor of biological chemistry at Queensland, said in a news release.
"When the nerve cells fused, we found that their electric circuits became coupled together and this affected the animal's behavior -- we can liken this to two rooms, each with its own light switch -- a problem with the electric circuit causes one switch to turn the lights on in both rooms," said Hilliard, a professor of biological chemistry at Queensland.
For their experiments, Hilliard and his colleagues triggered the fusion of neurons responsible for the nematode's smelling abilities. When the neurons expressed fusogens and fused, the worms were unable to track down food and failed to turn away from the smell of danger.
The study's results suggest cell fusion could play a role in a variety of neurodegenerative disorders.
"We know that viruses can infect the brain -- herpes simplex virus has been found in the brain cells of some patients with Alzheimer's disease -- causing havoc and resulting in disease," Giordano-Santini said.
In followup studies, scientists plan to investigate the possibility of neuron fusion in brain cells of mammals.
"Understanding more about neuronal fusion will allow us to determine how often it occurs in human disease conditions, and eventually develop ways to prevent it or to rescue neurons from this fate," Hilliard said.