An emergency study has identified what could be a biological link between Zika virus and a rare birth defect that leaves newborns with undersized heads and brains.
Researchers report after working—sometimes around the clock—with lab-grown cells over the past month, that Zika attacks the type of cell that forms the brain’s cortex, or outer layer. The virus makes those cells more likely to die and less likely to divide normally and make new brain cells. The findings appear in the journal Cell Stem Cell.
“While this study doesn’t definitely prove that Zika virus causes microcephaly,” says Guo-li Ming of the Johns Hopkins University School of Medicine, “it’s very telling that the cells that form the cortex are potentially susceptible to the virus, and their growth could be disrupted by the virus.”
Zika was recently declared by the World Health Organization a “public health emergency of international concern.” During an outbreak in Brazil and elsewhere in South America, doctors have come to believe that the virus—previously known for causing relatively mild flu-like symptoms—can also cause microcephaly in babies born to mothers infected during pregnancy. Doctors strongly suspect the virus may also be linked to cases of Guillain-Barré syndrome.
Ming says the association with microcephaly was suggested when Zika was found in fetuses and babies with the condition’s telltale small brains and heads. A US Centers for Disease Control and Prevention team traveled to Brazil late last month to assist in pinning down epidemiological evidence that the virus causes microcephaly.
3 Days After Exposure
In the meantime, a task force from three US universities had set about to look for a potential biological link explaining how the virus could block normal brain development in fetuses. Ming, a professor of neurology, neuroscience, and psychiatry and behavioral science at Johns Hopkins’ Institute for Cell Engineering, led the research with Hongjun Song, a neuroscientist at Johns Hopkins, and Hengli Tang, a virologist at Florida State University.
The researchers compared Zika’s effect on cortical neural progenitor cells to two other cell types: induced pluripotent stem cells and immature neurons. Induced pluripotent stem cells can give rise to any cell type in the body, including cortical neural progenitor cells. Cortical neural progenitor cells in turn give rise to immature neurons for the cortex.
