COVID-19 can cause brain cell fusion, triggering malfunction

A new study led by the University of Queensland (UQ) has shown that viruses, such as SARS-CoV-2, can cause brain cells to fuse, leading to malfunctions that can trigger chronic neurological symptoms.

According to the study published in the Science Advances journal on Wednesday, researchers have studied the effects of viruses on the nervous system, suggesting that SARS-CoV-2 has been detected in the brains of people with "long COVID" months after initial infection.

"We discovered COVID-19 causes neurons to undergo a cell fusion process, which has not been seen before," said Massimo Hilliard, co-author of the study and professor at UQ.

"After neuronal infection with SARS-CoV-2, the spike S protein becomes present in neurons, and once neurons fuse, they don't die," Hilliard noted. "They either start firing synchronously, or they stop functioning altogether."

The scholar compared the role of neurons to that of wires connecting switches to the lights in a kitchen and a bathroom.

"Once fusion takes place, each switch either turns on both the kitchen and bathroom lights at the same time, or neither of them," he said. "It's bad news for the two independent circuits."

"In the current understanding of what happens when a virus enters the brain, there are two outcomes - either cell death or inflammation," said Ramon Martinez-Marmol, another co-author and research fellow at UQ. "But we've shown a third possible outcome, which is neuronal fusion."

Martinez-Marmol mentioned that numerous viruses infect the nervous system and cause cell infusion, including HIV, rabies, Japanese encephalitis, measles, herpes simplex Virus, and Zika virus.

"Our research reveals a new mechanism for the neurological events that happen during a viral infection," he said. "This is potentially a major cause of neurological diseases and clinical symptoms that is still unexplored."