Leads to Chronic “Long COVID” Neurological Symptoms
By UNIVERSITY OF QUEENSLAND
Movie at 10 fps, with frames being acquired every 30 min. Images were recorded 24 h after transfecting hippocampal neurons with p15 and GFP. Each frame represents the maximum intensity projection, with GFP intensity adjusted to facilitate the visualization of newly appearing GFP-positive neurons. Credit: The Authors
Scientists at The University of Queensland
have discovered viruses such as SARS-CoV-2 can cause brain cells to fuse,
initiating malfunctions that lead to chronic neurological symptoms.
Professor Massimo Hilliard and Dr. Ramon
Martinez-Marmol from the Queensland Brain Institute have explored how viruses
alter the function of the nervous system.
SARS-CoV-2, the virus that
causes COVID-19, has been detected in the brains of people with ‘long
COVID’ months after their initial infection.
“We discovered COVID-19 causes neurons to undergo a cell fusion process, which has not been seen before,” Professor Hilliard said.
“After neuronal infection with SARS-CoV-2,
the spike S protein becomes present in neurons, and once neurons fuse, they
don’t die. They either start firing synchronously, or they stop functioning
altogether.”
As an analogy, Professor Hilliard likened 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.”
The discovery offers a potential explanation for persistent neurological effects after a viral infection.
“In the current understanding of what happens
when a virus enters the brain, there are two outcomes – either cell death or
inflammation,” Dr. Martinez-Marmol said.
“But we’ve shown a third possible outcome,
which is neuronal fusion.”
Dr. Martinez-Marmol said numerous viruses
cause cell fusion in other tissues, but also infect the nervous system and
could be causing the same problem there.
“These viruses include HIV, rabies, Japanese
encephalitis, measles, herpes simplex virus, and Zika virus,” he said.
“Our research reveals a new mechanism for the
neurological events that happen during a viral infection.
“This is potentially a major cause of
neurological diseases and clinical symptoms that is still unexplored.”
The researchers acknowledge the collaborative
efforts of Professor Lars Ittner and Associate Professor Yazi Ke from Macquarie
University, Associate Professor Giuseppe Balistreri from University of
Helsinki, and Associate Professor Kirsty Short and Professor Frederic Meunier
from The University of Queensland.
The research was published in Sciences
Advances.
Reference: “SARS-CoV-2 infection and viral
fusogens cause neuronal and glial fusion that compromises neuronal activity” by
Ramón Martínez-Mármol, Rosina Giordano-Santini, Eva Kaulich, Ann-Na Cho,
Magdalena Przybyla, Md Asrafuzzaman Riyadh, Emilija Robinson, Keng Yih Chew,
Rumelo Amor, Frédéric A. Meunier, Giuseppe Balistreri, Kirsty R. Short, Yazi D.
Ke, Lars M. Ittner and Massimo A. Hilliard, 7 June 2023, Sciences
Advances.
DOI: 10.1126/sciadv.adg2248
