As researchers across the globe rush to better understand the fast-spreading Zika virus, scientists at Florida State University have found new evidence to support what some have suspected – that the virus targets brain development cells.
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“There are case reports for the Zika virus where they show that certain brain areas appear to have developed normally, but it is mostly the cortical structures that are missing”, says Ming, a neuroscientist interested in brain disorders like microcephaly.
There are several other questions left to answer as well: why are the symptoms in adults so mild?
WASHINGTON (AP) Researchers say the Zika virus may be linked to a wider variety of “grave outcomes” for developing babies than previously reported and that threats can come at any stage of pregnancy.
As predicted, Zika virus attacked the human neural progenitor cells.
Nevertheless, circumstantial evidence has accumulated.
Importantly, the researchers linked problems to infections during each trimester of pregnancy, not just the first trimester that doctors have speculated would be the riskiest. But because researchers had conducted scant research on the virus before this year, they had little data to suggest how the virus could cause such damage.
The findings are the first concrete evidence of a link between the mosquito-borne virus and microcephaly, which until now had been circumstantial, said Guo-li Ming, a professor of neurology at Johns Hopkins’ Institute for Cell Engineering, and a co-leader of the research. In contrast, when the virus was applied to cultures of fetal kidney cells, embryonic stem cells, and undifferentiated iPS cells, it infected fewer than 10% of the cells by day 3.
The researchers noticed that the infected progenitor cells were not killed right away. But the horror doesn’t stop there; after these cells are exposed to Zika, the virus converts them into highly efficient factories for reproduction. That helped the virus to spread quickly through the cell population, he says. Many infected cells died, and others were disrupted so new cells could not be made effectively.
A study of nine pregnant women from the United States who travelled to countries where the Zika virus was circulating showed a greater-than-expected number of fetal infections and brain abnormalities, USA health officials said last week. In a preprint posted online on 2 March, neuroscientist Patricia Garcez and stem cell researcher Stevens Rehen at the D’Or Institute for Research and Education in Rio de Janiero, Brazil, report growing human iPS cells into clusters of neural stem cells called neurospheres, as well as into three-dimensional organoids that in some ways resemble a miniature version of the human brain.
“When the guy did the ultrasound he got his boss and said it was freakish because everything was fine but the sack was there but there was no foetus – it wasn’t a normal miscarriage”.
“Once the virus gets in the brain, these cells can produce more viruses”, Tang said.
And the idea that Zika may cause the condition by harming the specific kind of brain cell used in the study is feasible, he said. What makes the virus troubling is its potential link to microcephaly.
“We are trying to fill the knowledge gap between the infection and potential neurological defects”, says first author Hengli Tang, the team’s virologist whose lab studies RNA viruses like Zika, Dengue, and hepatitis C virus.
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The virus was able to infect up to 90% of neural progenitor cells in a sample leading to almost a third of cells dying and the growth of the rest being disrupted.
