Biochemical link between Zika and microcephaly discovered
8 Apr 2016 by Evoluted New Media
Scientists believe they have found a method by which Zika may cause microcephaly.
Scientists believe they have found a method by which Zika may cause microcephaly.
Researchers from the University of California have theorised that the virus is able to ‘hijack’ a protein called AXL found on the surface of neural stem cells and use it to gain entry to vulnerable cells.
Dr Arnold Kriegstein, senior study author, said: “While by no means a full explanation, we believe that the expression of AXL by these cell types is an important clue for how the Zika virus is able to produce such devastating cases of microcephaly, and it fits very nicely with the evidence that's available.”
Neural stem cells, known as radial glial cells, are precursors for brain cell types such as neurons and astrocytes that help build the cerebral cortex. Disruption of this range of cell types is consistent with symptoms associated with fetuses affected by the Zika virus. Although not scientifically proven it is ‘strongly suspected’ by the World Health Organisation that the Zika virus causes microcephaly, eye lesions and a smooth brain instead of one with wrinkles (lissencephaly) in fetuses.
Researchers used single cell RNA sequencing to look for AXL in different cells types in brain tissue samples from mice, ferrets, human stem cells and developing human neural tissue. All samples showed radial glial cells expressed AXL. Antibody trackers were then used to see where the AXL receptor was most likely to be found and scientists discovered AXL was more likely to be found in areas where stem cells come into contact with cerebrospinal fluid or blood vessels. The scientists believe this is how Zika is able to reach vulnerable cells.
Dr Kriegstein said: “We still don't understand why Zika in particular is so virulent to the developing brain. It could be that the virus travels more easily though the placental-fetal barrier or that the virus enters cells more readily than related infections."
The next steps to be taken by the researchers will see if inhibiting AXL can prevent Zika –as it is not the only receptor linked to the virus. If successful then creating an AXL inhibitor for expectant mothers could be the next step to prevent Zika getting into the developing fetus.
The research was published in Cell Stem Cell.
