Cold Spring Harbor Laboratory Pregnancy Study Links Maternal Inflammation to Male Autism Traits
To truly understand autism spectrum disorder, we have to look beyond the brain,
said Lucas Cheadle, an associate professor at Cold Spring Harbor Laboratory. His team’s new findings suggest maternal immune activation and changes within the placenta act as a gateway to autism for some unique individuals.
Scientists investigating the origins of autism spectrum disorder found that inflammation during pregnancy damages specific cells in the placenta and triggers autism-like traits exclusively in male mice. The research shows that developmental disruptions caused by immune activation occur earlier in gestation than previously documented. Researchers triggered an immune response in pregnant mice using a substance that mimics a viral infection without introducing an actual pathogen.
Critical Vulnerability Window on Day 12.5 of Gestation
The experiments revealed that mouse fetuses were especially vulnerable when inflammation occurred 12.5 days into the pregnancy. Irene Sanchez Martin, a postdoctoral researcher in the Cheadle laboratory, observed that approximately one-third of the fetuses displayed developmental abnormalities within 24 hours of the simulated viral exposure.
Researchers have studied the effects of maternal immune activation for decades, but these findings reveal signs of developmental disruption earlier than researchers had previously observed. Across every experiment, autism-like traits manifested solely in male fetuses, while female fetuses continued normal development. This distinction emerged before hormonal surges or sexual differentiation of the brain typically occur in mice.
Spongiotrophoblast Damage in the Placenta
Investigators examined the placenta to understand why male fetuses sustained damage while females appeared unaffected. Their focus centered on spongiotrophoblasts, specialized cells located where maternal and fetal cells interact. Normal fetuses maintained healthy spongiotrophoblast layers, but affected male fetuses showed visible cellular damage in this region.
Spongiotrophoblasts enable the maternal immune system to tolerate the genetically distinct fetus during pregnancy. Maternal immune activation disrupts this protective function, allowing the mother’s immune response to harm the developing fetus.
Contrasting Responses Between Male and Female Fetuses
Female embryos may withstand inflammation due to protective biological mechanisms or because male embryos produce distinct proteins that provoke an unfavorable immune response. Cheadle noted that identifying the female protective mechanism could eventually help researchers assist vulnerable males.
The research team plans to study both sexes to isolate the distinct biological pathways involved. These experiments in mice do not establish that the same mechanisms cause autism in humans, but they point researchers toward the placenta and maternal-fetal immune interactions as critical areas for early developmental study.
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