Studies have long shown that maternal infection during pregnancy increases the risk that a child will develop autism. A newly published study may help explain why – and provide early guidance for the development of potential treatments.
The new study, by autism researchers at the University of California-Davis Center for Neuroscience, appears in the Journal of Neuroscience.
The researchers documented abnormal brain-cell development in the pups of pregnant mice that had been injected with viral RNA to mimic a flu (influenza) infection. The brain cells of these pups had much higher levels of a class of immune molecules called major histocompatibility complex 1 (MHC1).
The high MHC1 levels, in turn, interfered with the brain cells’ ability to form connections with other brain cells. This is in line with earlier research suggesting that autism stems from the altered development of brain connections.
In their experiments, the researchers then blocked the development of the excess MHC1 molecules in the pups’ developing brains. This restored the normal growth of brain-cell connections.
“We know that activation of a mother’s immune system during pregnancy is a risk factor for autism, but how we get from risk factor to brain changes that contribute to autism has not been clear,” comments Daniel Smith, Autism Speaks senior director for discovery neuroscience.
“We’re still a long way from knowing whether these results will lead to safe, new treatments,” Dr. Smith adds. “But studies like this – which point to specific biochemical pathways and abnormalities in connections between neurons – take us one step closer.”
The study’s lead investigators – Bradford Elmer and Myka Estes – are pursuing their research with the support of Autism Speaks’ Weatherstone Predoctoral Fellowships. The study’s senior author, Kimberley McAllister, is the recipient of an earlier Autism Speaks research grant that helped lay the foundation for the current study.