Year 2

We set out to establish an in vitro human neuronal model of autism spectrum disorders (ASD) by generating induced pluripotent stem (iPS) cell lines from patients harboring specific genetic mutations in syndromic forms of autism, such as Rett Syndrome (RTT) and Tuberous sclerosis (TS). We then differentiated them into neural progenitor cells (NPCs) and forebrain neurons, in order to compare their differentiation potential and to characterize mutation-associated deficits at the cellular and molecular level. Previously published data on cellular and animal models indicate that synaptic deficits are a major feature of the pathophysiology of RTT and TS.

We employed patient-derived induced pluripotent stem cells (iPSCs) from male RTT patients and gender-matched parental controls to probe for functional and molecular deficits in RTT. A similar approach was taken for TS.
As MECP2 is expressed in both the developing and mature central nervous system, we investigated deficits that may arise during early developmental stages (i.e. at the neural progenitor cell or NPC stage), which could then significantly affect neurodevelopmental processes such as neurogenesis and gliogenesis. By quantitative proteomics, we showed that the RTT cells have changes on the molecular level, at both the NPC and neuron stage, compared to their WT control, and that these changes may reflect some of the deficits in the developmental process. We report delays in maturation, such as misregulation of LIN28 at the NPC stage and subsequent deficits in glial differentiation.

Taken together, these results provide a framework for identifying novel early pathways that are perturbed in RTT, as well as potential therapeutics to minimize functional deficits. More generally, it will be of interest to see if these pathways and possible therapeutics may carry over to other related forms of neurodevelopmental disorders, in particular, idiopathic autism.