ASF funded fellow Nick Goeden from USC examines the role of the placenta.
Blog written by Priyanka Shah, ASF intern
Many researchers are studying various factors during pregnancy that can lead to an increased risk of autism and other neurodevelopmental disorders in children. Maternal infection and inflammation have been shown to be risk factors for autism and schizophrenia. For example, in recent news, we have seen how expecting mothers infected with the Zika virus have given birth to babies with a high-risk for brain damage and other abnormalities. So, studying how maternal health (in this case, a viral infection) affects the fetus can help us predict for possible disorders and possibly even prevent them.
In particular, at the University of Southern California, Nick Goeden and colleagues studied how the placenta was affected after the mother experienced inflammation. The placenta is a tissue in a woman’s uterus that provides nourishment to the fetus through the umbilical cord. The placenta also produces an important chemical messenger, called serotonin, which is transmitted to the fetus and plays a role in organizing the brain during development. After birth, it helps regulate emotions and has been implicated in depression and anxiety.
Researchers decided to use a mouse model to see how maternal inflammation can affect the production of serotonin in the placenta and brain development in the fetus. To do this, they used a chemical that induces inflammation in pregnant mice, and mimics flu-like conditions seen in humans. They found that the amount of serotonin in the placenta drastically increased, leading to increased amounts of serotonin in the fetal brain. During brain development, brain cells migrate and become connected together like an electric network. The formation of certain brain cells that specifically help move serotonin around was disrupted, which means that the fetus’ brain became wired differently. Because of this, some of the behaviors serotonin helps control could have been affected. And in fact, other studies have shown how maternal infection during pregnancy can lead to increased anxiety or depression-like symptoms in the offspring.
This study shows that even mild inflammation during pregnancy can induce a series of events that eventually disrupts the development of the fetal brain. Although these children will have a higher risk for known mental disorders such as ASD or schizophrenia, these diagnoses are not guaranteed. Our next steps in this line of research should be to see the long-term effects of inflammation on the serotonin-specific brain cells and related behaviors. Researchers should also look at how other infections and viruses might be changing the production of other chemical messengers or molecules in the placenta. Understanding the biological mechanisms of the placenta and of fetal brain development can help direct new research into prevention and therapy for neurodevelopmental disorders in children.