Year 1
The main goal of this project is to establish a cell culture model human neuronal model of autism spectrum disorders (ASD) by generating induced pluripotent stem (iPS) cell lines from patients harboring mutations in genes associated with autism, differentiating them into forebrain neurons, and characterizing their synaptic defects at the cellular and molecular level. We have successfully obtained iPS cells from two autism spectrum disorders, tuberous sclerosis complex (TSC) and Rett syndrome (RTT). We obtained fibroblasts from patients with mutations in the TSC1 and TSC2 genes through the Coriell biorepository. We then reprogrammed them into several TSC patient-specific iPS cell lines. Furthermore, we have obtained male MECP2 mutant iPS cell lines from the lab of Dr. Alysson Muotri to study in parallel with the TSC lines.
We differentiated ASD iPS cell lines into neural progenitor cell (NPCs) and have been examining differences in protein levels and signaling pathways in these cells. Pathway analyses from MECP2 mutant NPCs suggest there may be a marked deficit in several major intracellular signaling pathways, and we are validating those deficits by biochemical analyses and genetic manipulations. Both TSC and RTT forebrain neurons show significant differences in synaptic regulation compared to their respective controls. Alterations in synaptic regulation are being assessed by gene expression analysis, staining for synaptic markers, and electrophysiology. We have made major progress toward realizing our goal of establishing novel iPS cell models for ASD. Furthermore, we obtained very interesting data that should help us elucidate the cell signaling deficits that lead to neuronal dysfunction.