A new stem cell study by Yale School of Medicine sheds light on autism causes and may facilitate drug development for autism treatment. The findings of the study have been recently published in the journal Cell.
Autism-spectrum disorders (ASD) appear during brain development, but in most cases doctors are unable to understand a clear origin or genetic basis behind this. Recent studies on ASD suggest that the cause might hide in abnormal development of the cerebral cortex during the fetal period. The Yale team of researchers aimed to find out what goes wrong as the cerebral cortex develops.
The scientists took skin cells of four boys with autism-spectrum disorders (ASD) and their autism-free family members, mostly fathers, turned these cells into induced pluripotent stem cells able to generate any cell type and stimulated these cells to develop into three-dimensional miniature early forebrains. Then they compared gene expression and development of brain cell types in patients and their healthy relatives. Patients in the study had macrocephaly (increased head size) which indicates severe autism spectrum disorder.
The research has shown considerable differences in mini-brains generated from ASD and ASD-free cells.
The expression of genes involved in synapse assembly, neuronal development, and cell proliferation was poorly regulated in mini-brains produced from cells of ASD patients. The patients’ cells divided faster than their healthy relatives' cells, and inhibitory neurons production in ASD patients was increased, while that of excitatory ones was not affected.
Besides, the researchers noticed a 10-fold increase in expression of a gene called FOXG1, which plays an important role in the early brain development. When they corrected the FOXG1 overexpression, overproduction of inhibitory neurons in patient’s cells ceased to continue, and the researchers were able to reverse some of the neurobiological changes in micro-brains. The scientists also discovered a link between by how much this gene was over expressed and the size of a patient’s head and autism severity.
The researchers suggest that FOXG1 could be used as a potential biomarker of severe ASD cases and may also serve as a potential drug target.
Using the similar approaches may help shed light on other diseases which causes remain unknown, such as Alzheimer’s disease or Parkinson’s, etc.