Haifa researchers: Autism linked to neuron development in embryos

Illustration of a human fetus. Source: Shutterstock
Illustration of a human fetus. Source: Shutterstock

PESACH BENSON
By JNS  Published: July 31, 2023

Accelerated growth of neurons associated with children on the spectrum.

University of Haifa researchers have discovered a significant association between autism and accelerated development of neurons in embryos.

The findings shed new light on the possible origins of autism and open up possibilities for new treatments.

An estimated 75 million people have autism spectrum disorder, a developmental disability caused by differences in the brain. People on the autistic spectrum frequently have difficulties with social communication and interacting with others, or exhibit repetitive or restricted behaviors. They often have different ways of learning, moving or paying attention.

The research, led by Dr. Shani Stern from the Department of Neurobiology at the University of Haifa, focused on children with autism who had genetic mutations as the underlying cause of their condition.

By studying neurons at the embryonic stage, the team found evidence of rapid neuron development that was not observed in children without autism. Additionally, the neurons displayed signs of rapid deterioration, characterized by low connectivity.

“Neurons that develop at a normal rate typically develop defense mechanisms for their complex activities, such as handling ions and neurotransmitters, which can be toxic. The accelerated development we observed in children with autism may have caused them to be exposed to these challenges before having developed adequate protective mechanisms,” explained Stern.

The team’s study was published in Translational Psychiatry, a peer-reviewed journal, earlier in July.

Traditionally, research into autism caused by genetic mutations has often relied on mouse models, focusing on post-birth stages of neuron development. However, Stern’s approach involved reprogramming mature cells from specific individuals into induced stem cells, which were then transformed into neurons. This enabled the researchers to track the development of neurons even before birth.

The study compared the development of cortical neurons in children with autism caused by various gene mutations to their unaffected siblings, forming the control group. Cortical neurons were chosen due to their known involvement in the changes observed in the brains of children with autism.

Regardless of the specific genetic mutation, all children with autism exhibited accelerated cortical neuron development during the embryonic stage and early months of life. At this early stage, the neurons were considered “mature,” displaying action potentials, strong electrical currents, and even forming active neuronal networks. In contrast, the neurons of the control group did not exhibit such advanced development at the same stage.

However, as the control group’s neurons reached the stage of producing action potentials and networks, the cortical neurons of children with autism had already begun to deteriorate, showing reduced connectivity.

Stern suggested that the early accelerated development could be responsible for the subsequent deterioration.

“Cortical neurons perform complex operations that can potentially damage them, but during normal development, they develop defense mechanisms before becoming active. The accelerated development observed in children with autism may have led to their exposure to stressors before they were equipped to handle them, potentially harming the neurons.”

The research further revealed that the phenomenon of accelerated development followed by rapid deterioration was consistent across children with autism caused by different gene mutations. The research team said this indicates that this pattern might be a characteristic feature of autism in general.

“The results of the study show that children with developmental delays actually start with developmental acceleration. The commonality of these results across various genetic mutations and chromosomes suggests that this could be a defining characteristic of the brains of children with autism,” Stern said.

The discovery of this association between accelerated neuronal development and autism opens up new possibilities for targeted interventions and potential treatments. Stern and her team are now focused on investigating compounds and drugs that could slow down this rapid development, offering protection to the developing neurons and potentially providing new therapeutic strategies for autism.