Skin cell study provides intriguing clues about ASD

Researchers report that in a subgroup of children with autism, brain cells grow unusually fast and have too few connections between them. 

M. C. Marchetto and colleagues collected skin cell samples from children with autism who also had enlarged brains. (Between 20 and 30 percent of children with autism exhibit brain overgrowth.) The researchers reprogrammed the skin cells to produce precursor cells found in the developing brain. 

The researchers found that the cells from autistic individuals grew at a faster rate than those from controls, and that these cells activated their genes in a different pattern. Genes related to cell growth were more active in the samples from the group with autism, leading to more cells with less connectivity. This, the researchers say, can lead to an enlarged head and faulty neural networks that cannot properly transmit signals. 

Marchetto and colleagues found that the abnormal genes in the samples from individuals with autism belonged to the Wnt signaling pathway. The researchers had previously discovered that mice lacking Wnt genes display symptoms resembling autism, including social anxiety and repetitive behavior. 

“Interestingly,” the researchers say, “defects in neuronal networks could be rescued by insulin growth factor 1 (IGF-1), a drug that is currently in clinical trials for ASD.” The researchers do not yet know whether IGF-1 acts by altering the Wnt pathway.

Citations

“Altered proliferation and networks in neural cells derived from idiopathic autistic individuals,” M. C. Marchetto, H. Belinson, Y. Tian, B. C. Freitas, C. Fu, K. C. Vadodaria, P. C. Beltrao-Braga, C. A. Trujillo, A. P. D. Mendes, K. Padmanabhan, Y. Nunez, J. Ou, H. Ghosh, R. Wright, K. J. Brennand, K. Pierce, L. Eichenfield, T. Pramparo, L. T. Eyler, C. C. Barnes, E. Courchesne, D. H. Geschwind, F. H. Gage, A. Wynshaw-Boris, and A. R. Muotri, Molecular Psychiatry, July 5, 2016 (online). Address: Anthony Wynshaw-Boris, [email protected]. 

—and— 

“Scientists uncover common cell signaling pathway awry in some types of autism,” Science Daily, August 26, 2016.