Recent studies have been shedding light on the critical role our gut microbiome plays in overall health, influencing everything from weight and mental health to immune responses and the development of autoimmune diseases like lupus and type 1 diabetes. Now, a new study published in The Journal of Immunology has uncovered a potential link between the gut microbiome and autism through animal studies. However, it’s not the child’s microbiome that appears to play a role in autism development, it’s the mother’s.
“The microbiome can shape the developing brain in many ways,” explained John Lukens, lead researcher and PhD student at the University of Virginia School of Medicine. He added, “It is crucial in calibrating how the offspring’s immune system will respond to infection, injury, or stress.”
The researchers suggest that a molecule called interleukin-17a (IL-17a), produced by the immune system, may be key to this link. IL-17a has been associated with conditions like rheumatoid arthritis, multiple sclerosis, and psoriasis, and it plays a significant role in fighting infections, particularly fungal ones. Importantly, it also affects brain development during pregnancy.
To test their hypothesis, the team focused on blocking IL-17a in lab mice. They worked with two groups of female mice: one with gut microbiomes that made them prone to an IL-17a-induced inflammatory response, and the other as a control group with a neutral microbiome.
When IL-17a was blocked, the pups from both groups displayed typical neurodevelopmental behaviors. However, without intervention, the pups born to mothers from the first group developed autism-like behaviors, including social and repetitive challenges. This suggested that the microbiome of the mother was influencing the offspring’s neurodevelopment.
To confirm this connection, the researchers conducted a fecal transplant from the first group (the one with the inflammatory response-prone microbiome) into the second group. As expected, the pups from the second group—now with microbiomes resembling those of the first—developed autism-like behaviors.
While these results come from animal studies and may not directly translate to humans, they offer an intriguing path forward for autism research, showing that the health of the mother’s gut may contribute to the onset of neurodevelopmental conditions.
The next step, according to Lukens, is to determine if similar correlations exist in humans and to pinpoint which elements of the mother’s microbiome are linked to autism. There may also be other molecules at play. As Lukens concluded, IL-17a might be just one piece of a much larger puzzle.
