A new study may have uncovered how the Zika virus, which has been spreading through the Caribbean and Latin America, could be causing the birth defect microcephaly.
For this research, a team cultured cells from the fetal brain that would have gone on to develop into the cortex, which is responsible for higher brain functions. The team infected these cells, called the cortical neural progenitor cells, and two other types of cells, induced pluripotent stem cells and immature neurons, with the Zika virus.
After just three days, 90 percent of the cortical neural progenitor cells were infected. The researchers noted that these cells were no longer able to go through cell division normally, which meant that they were not reproducing new and healthy cells that are vital for fetal brain development. The researchers also found that the Zika-infected cells tended to die more frequently. The other two types of cells, however, were not as greatly affected by the virus.
"Studies of fetuses and babies with the telltale small brains and heads of microcephaly in Zika-affected areas have found abnormalities in the cortex, and Zika virus has been found in the fetal tissue," researcher Guo-li Ming, a professor of neurology, neuroscience, and psychiatry and behavioral science at Johns Hopkins' Institute for Cell Engineering, said in a news release. "While this study doesn't definitely prove that Zika virus causes microcephaly, 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."
The team hopes that by knowing the cells that the virus targets, researchers can create new forms of treatment that would ideally prevent the virus from affecting these cells.
"Now that we know cortical neural progenitor cells are the vulnerable cells, they can likely also be used to quickly screen potential new therapies for effectiveness," addedsenior author of the study, Hongjun Song, a professor of neurology and neuroscience at the institute.
Since the start of the Zika outbreak last year, Brazil, the country that has been affected the most, has seen an abnormal spike in the number of microcephaly cases. Although this study did not prove a causal link, the findings do offer some more insight into how the virus is attacking the fetal brain.
The study was published in the journal Cell Stem Cell.
