Zika scientists: We’re back to square one
A widely accepted theory about the way Zika infects fetal brain cells may have been all wrong, a discouraging discovery that shows the little-understood virus may be even more of a mystery than originally thought, according to local researchers.
“It basically means we’re back to square one,” said Michael Wells, researcher and fellow at the Harvard Department of Stem Cell & Regenerative Biology. “It would have been great if we did find a way the virus enters the brain. But apparently, it’s not going to be that easy.”
He added, “We had a theory. It didn’t pan out. Now we don’t know.”
The theory was a consensus among scientists that the virus — which has been linked to the devastating birth defect microcephaly, characterized by an abnormally small skull and brain — entered the fetal brain through a specific pathway, called the AXL surface receptor, on the surface of developing cells.
But when the researchers knocked out that pathway in miniature lab-grown brains, the virus still made its way into the tissue.
Scientists have focused on developing vaccines for the virus, and this discovery would not impede that progress. But Wells said until a vaccine proves effective, “we need to keep trying to see how this virus is causing this much damage.”
“I think we’ve been underestimating this virus since day one. We as a society, not just we as scientists,” Wells said. “We’re not close to stopping it.”
The 3-D brain models were grown using a technology developed by Cambridge-based Novartis, which allowed the researchers to mimic early neural development using brains grown from adult stem cells.
“It’s the same structure as a three-month-old fetus,” said Ajamete Kaykas of Novartis, one of the paper’s authors.
Scientists need to focus now on finding the mechanism responsible for allowing the virus into those cells, he said, which stop populating the brain with neurons once the virus hits.