Researchers have discovered a piece in the puzzle of how the Zika virus spreads in human cells and neutralizes the body’s defenses.
A study by scientists at the University of California, San Diego School of Medicine answered a fundamental question posed by biologists: What happens when the virus enters a human cell?
Zika infections lead to modifications in the genetic material of both the virus itself and humans’ immune systems, influencing the virus’ spread and the body’s response, according to the study published Thursday in Cell Host & Microbe.
The virus, which is known to cause devastating birth defects, spreads from humans to mosquitoes and back to human through bites. Humans can also spread Zika through sex.
While humans’ genetic material is made up of DNA and RNA, some viruses’ genomes — including Zika and HIV — are comprised only of RNA. In humans, RNA carries genetic information from DNA to create new cells.
Researchers found that when the Zika virus infected a human cell, the cell modified viral RNA to get rid of the infection. But that adaptation triggered human enzymes that may have impacted the cell’s protective shield. The Zika infection also induced modifications on human RNA, according to the study.
Changing viral RNA let the virus “hide in plain sight,” said Tariq Rana, the lead author of the study and a professor of pediatrics at UC San Diego.
That discovery probably won’t help find a vaccine for Zika, but it could contribute to developing drugs to prevent the devastating birth defects in some babies born to women who contracted the virus while pregnant, said Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston. Hotez was not involved in the study.
It might also help scientists develop drugs in the future that can specifically target and stop Zika from changing RNA, Rana said.
Understanding how Zika changes RNA opens the door to studying when fetuses are harmed during pregnancies and what the potential risk factors may be, said Amesh Adalja, a senior associate at the Center for Health Security, part of the University of Pittsburgh Medical Center.
The research may be a key to understanding how Zika causes so much damage to a developing fetus, said Adalja, who was not part of the study.
“What you’re seeing with Zika is science progressing at breakneck speed to discover mysteries about this virus that no one paid attention to for decades and decades,” Adalja said.
Kaiser Health News is a national health policy news service that is part of the nonpartisan Henry J. Kaiser Family Foundation.