Neurons made from stem cells reveal cellular flaws in autism

Researchers have uncovered cellular abnormalities in Timothy syndrome by regenerating neurons from individuals with the rare autism-related disorder, according to a study published 27 November in Nature Medicine.Using a mix of chemicals in a dish, the researchers reprogrammed skin cells from individuals with Timothy syndrome into so-called induced pluripotent stem (iPS) cells and then coaxed these cells to differentiate into neural precursor cells and neurons.The cells derived from individuals with Timothy syndrome show a host of defects, including abnormal calcium signaling and low numbers of cells that can form long-range connections. Notably, Timothy neurons produce more catecholamines, a class of chemical messengers, compared with neurons reprogrammed from healthy individuals. These chemicals have been linked to autism and, more often, to bipolar disorder and depression.This chemical excess is largely reversed when researchers expose the cells to a drug called roscovitine, which blocks the flow of calcium across the cell membrane.The Timothy syndrome gene, CACNA1C, makes a protein needed for a certain type of calcium channel. Mutations in the gene, reported in only a few dozen people, cause heart defects, physical malformations and, usually, autism.Using the iPS cell approach with rare forms of autism, "you can find things that are interesting potential clinical leads,” says lead investigator Ricardo Dolmetsch, assistant professor of neurobiology at Stanford University in Palo Alto, California. “In a way, it gives you a better preclinical model than we’ve had before."Read more at...SFARI, December 2011.