The object of this proposal is to enhance our limited understanding of the pathophysiology of autism spectrum disorders (ASDs), which is a devastating neurodevelopmental condition affecting 1 in 88 US children. This will be accomplished by studying human neurons induced from human embryonic stem cells (ESCs) that are conditionally knock out for neurexin-1 (Nrxn1), a gene that is frequently mutated in patients with ASDs. The synaptic role of Nrxn1 and its functional contribution to autism in human neuronal context has not been studied, which makes this study unique. Preliminary data indicates the feasibility of this approach, whereby ESCs conditionally mutant for Nrxn1 locus has been generated. Using these cells, human excitatory neurons will be generated whereby Nrxn1 gene will be conditionally knocked out during neuronal development. Based on the hypothesis that Nrxn1 is required for proper synaptic function in human neurons, I will compare synapse development and function (synaptic transmission) in control and Nrxn1 mutant human neurons. Nrxn1 function in synapse development will be monitored by morphological studies examining synapse density and size as well as synaptic vesicle cycling. Using, electrophysiolgical assays, I will assess both pre and postsynaptic functions of Nrxn1 in mediating synaptic transmission at human excitatory synapses. In total, these experiments attempt to determine the mechanism by which mutated Nrxn1 influence human synaptic transmission and as a consequence, contribute to autism, using a combination of experimental approaches that assess synaptic function. !

Public Health Relevance

This project attempts to address the role of synaptic defects in autism spectrum disorders (ASDs), a highly penetrant complex group of neurodevelopmental disorders. Neurexin-1 (Nrxn1) is a synaptic cell adhesion molecule that is frequently mutated in patients with ASDs. Understanding the pathophysiology of Nrxn1 function in human neurons will contribute to our understanding of the mechanisms underlying autism and lead to advances in identifying new therapeutic targets and treatment strategies.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
1F32HD078051-01
Application #
8594881
Study Section
Special Emphasis Panel (ZRG1-F03A-N (20))
Program Officer
Parisi, Melissa
Project Start
2013-09-30
Project End
2016-09-29
Budget Start
2013-09-30
Budget End
2014-09-29
Support Year
1
Fiscal Year
2013
Total Cost
$49,214
Indirect Cost
Name
Stanford University
Department
Neurosciences
Type
Schools of Medicine
DUNS #
009214214
City
Stanford
State
CA
Country
United States
Zip Code
94305
Chanda, Soham; Ang, Cheen Euong; Davila, Jonathan et al. (2014) Generation of induced neuronal cells by the single reprogramming factor ASCL1. Stem Cell Reports 3:282-96