Boston | Scientists have found a very small protein in our body that can swallow up and quarantine the Zika virus, dramatically reducing its ability to infect cells, an advance that may lead to new therapies to fight the infection linked to serious birth defects.
The interferon-induced protein 3 (IFITM3), in some cases, can also prevent Zika virus from killing our cells, researchers said. The findings, from the University of Massachusetts Medical School (UMMS) in the US, suggest that boosting the actions of IFITM3 may be useful for inhibiting Zika virus and other emerging viral infections.
This work represents the first look at how our cells defend themselves against Zika virus’ attack, said Abraham Brass, assistant professor at UMMS. Our results show that Zika virus has a weakness that we could potentially exploit to prevent or stop infection, said Brass.
Researchers developed a suite of genomic tools to probe how human cells respond to pathogens and how these invaders exploit host cell factors and proteins to replicate. The mosquito-transmitted Zika virus typically causes relatively mild symptoms in infected adults.
An ongoing epidemic of Zika virus began in early 2015 in Brazil and with it new evidence emerged that Zika virus infection of mothers during early pregnancy can result in microcephaly, a severe brain defect in infants. There is no treatment for Zika virus infection.
The best way to prevent the infection is to limit potential exposure to the infected mosquitoes that carry the disease. From their earlier research on dengue virus and other flaviviruses related to Zika, researchers had a hunch that IFITM3 might reduce or block viral infection. Using the IFITM3 tools and assays they had developed for studying dengue and influenza viruses, they were able to rapidly test IFITM3′s effect on Zika virus.
Found in nearly all human cells, IFITM3 works to alter the cell membrane, making it more difficult for viruses to penetrate this outer defence. The Brass lab found that when IFITM3 levels are low, Zika virus can more readily infiltrate into the cell interior and cause infection.
Conversely, they discovered that when IFITM3 is abundant and on guard, it strongly prevents Zika virus from reaching the interior of the cell and so blocks its infection. In effect, we see that IFITM3 allows our cells to swallow up and quarantine the virus thereby stopping their own infection, and also the infection of neighbouring cells said George Savidis, a research associate in the Brass lab.
We think this also reduces the levels of cell death caused by Zika virus, Savidis said. This work shows that IFITM3 acts as an early front line defender to prevent Zika virus from getting its hands on all of the resources in our cells that it needs to grow, said Savidis. The study appears in the journal Cell Reports.
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