RECIFE, BRAZIL (REUTERS) – Researchers at Maryland-based Johns Hopkins University School of Medicine announced on Friday (March 4) they found a potential link between the Zika virus and microcephaly, a neurological abnormality that causes small heads and brains in fetuses and babies.
Scientists said in a release the virus “selectively infects cells that form the brain’s cortex, or outer layer, making them more likely to die and less likely to divide normally and make new brain cells”.
The researchers used lab-grown human stem cells in and experiment conducted in less than a month that they hope will aid in creating drugs to protect the cells or ease existing infections of the virus.
Much remains unknown about Zika, including whether the virus actually causes microcephaly, but Brazil said it has confirmed more than 500 cases, and considers most of them to be related to Zika infections in the mothers. Brazil is investigating more than 3,900 additional suspected cases of microcephaly.
Zika, carried by mosquitoes which transmit the virus to humans, is affecting large parts of Latin America and the Caribbean and is likely to spread to all countries in the Americas except for Canada and Chile, the World Health Organization has said.
“One of the major reasons why this is a global emergency is because of the suspected link of microcephaly and Zika virus. However, it’s very difficult to study that in humans because what is missing is a model system where we can address causality. So, as a first step, we thought we could use stem cells as a tool to answer this question. And that’s how we started. We started to turn the induced pluripotent stem cells in humans into neural stem cells and the cell types that are responsible for developing the brain,” neurology and neuroscience professor Hongjun Song said.
The researchers compared Zika’s effect on cortical neural progenitor cells to two other cell types: induced pluripotent stem cells (IPSCs) and immature neurons, according to a release from Johns Hopkins.
“So what we started is to actually, using different cell types – we human used IPSCs, we also used neural progenitor cells derived from IPSCs as well as neurons derived from IPSCs to to test which cell type actually, is the risk target, for this Zika virus,” said Guo-li Ming, a professor of neurology, neuroscience, and psychiatry and behavioral science at Johns Hopkins’ Institute for Cell Engineering.
“What we found here is actually the first evidence that there is a target cell that the Zika virus can infect. And there’s an indication because these cells are generating the other cells to populate the brain, that means there’s a potential link, maybe the neural progenitor cells – because in our study we show that after infection, there’s an increase in cell deaths of this neural progenitor cells. So that means maybe less neurons or neural populations are generated,” Ming said.
“As a scientist, we can be involved in society and make a contribution right away. Because in general our research takes decades to have an impact on society, but in this case it could be very fast,” he said.
The World Health Organization declared the outbreak an international health emergency on Feb. 1, citing a “strongly suspected” relationship between Zika infection in pregnancy and microcephaly. Scientists are also studying a potential link between Zika infection and Guillain-Barre, a rare neurological disorder that can weaken the muscles and cause paralysis.
Results of the experiments can be found in the March 4 edition of the journal Cell Stem Cell.