Abstract
Using human induced pluripotent stem cells (iPSC), recent studies have shown that the events underlying autism spectrum disorders (ASD) can occur during neonatal development. We previously analyzed the iPSC-derived pyramidal cortical neurons of a subset of patients with ASD carrying de novo heterozygous mutations in postsynaptic SHANK3 protein, in culture. We reported altered spinogenesis of those neurons. The transplantation of human iPSC-derived neuronal precursors into mouse brain represents a novel option for in vivo analysis of mutations affecting the human brain. In this study, we transplanted the neuronal precursor cells (NPC) into the cortex of newborn mice to analyze their integration and maturation at early stages of development and studied axonal projections of transplanted human neurons into adult mouse brain. We then co-transplanted NPC from a control individual and from a patient carrying a de novo heterozygous SHANK3 mutation. We observed a reduction in cell soma size of selective neuronal categories and in axonal projections at 30 days post-transplantation. In contrast to previous in vitro studies, we did not observe any alteration in spinogenesis at this early age. The humanized chimeric mouse models offer the means to analyze ASD-associated mutations further and provide the opportunity to visualize phenotypes in vivo.
Highlights
Using human induced pluripotent stem cells, recent studies have shown that the events underlying autism spectrum disorders (ASD) can occur during neonatal development
The study consists of analysis of dendritic spines together with comparative analysis of soma areas and axonal projections between co-transplanted control neurons (CTR) and ASD cells from a male patient with a frameshift mutation in SH3 and multiple ankyrin repeat domain 3” (SHANK3) referred as L1142Vfs*153 located in the proline-rich domain of SHANK3 protein1. (c) Primary dendrite segment of human pyramidal neuron at 50 days post-transplantation with corresponding 3D reconstruction
We recently published an in vitro characterization of induced pluripotent stem cells (iPSC)-derived neurons from control individuals and patients with ASD with single heterozygous de novo mutations in SHANK3, which is a scaffolding protein expressed at synapses of excitatory n eurons[1]
Summary
Using human induced pluripotent stem cells (iPSC), recent studies have shown that the events underlying autism spectrum disorders (ASD) can occur during neonatal development. We previously analyzed the iPSC-derived pyramidal cortical neurons of a subset of patients with ASD carrying de novo heterozygous mutations in postsynaptic SHANK3 protein, in culture. Quantitative analysis of primary dendritic spines of human iPSC-derived neurons kept either in culture or transplanted into neonate mice brain. Recent alternative protocols including the transplantation of human cells, derived either from human embryonic stem cells (ESC) or from human iPSC, offer the possibility to analyze the projection patterns of grafted human cortical neurons within the adult mouse brain[20]. We co-transplanted, for the first time, the neurons from the control individual and from an ASD patient with a heterozygous truncated SHANK3 mutation to study at early stages of neuronal maturation some key morphological parameters of mutated neurons, under in vivo conditions
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