Aberrant calcium channel splicing drives defects in cortical differentiation in Timothy syndrome

Elife. 2019 Dec 23:8:e51037. doi: 10.7554/eLife.51037.

Abstract

The syndromic autism spectrum disorder (ASD) Timothy syndrome (TS) is caused by a point mutation in the alternatively spliced exon 8A of the calcium channel Cav1.2. Using mouse brain and human induced pluripotent stem cells (iPSCs), we provide evidence that the TS mutation prevents a normal developmental switch in Cav1.2 exon utilization, resulting in persistent expression of gain-of-function mutant channels during neuronal differentiation. In iPSC models, the TS mutation reduces the abundance of SATB2-expressing cortical projection neurons, leading to excess CTIP2+ neurons. We show that expression of TS-Cav1.2 channels in the embryonic mouse cortex recapitulates these differentiation defects in a calcium-dependent manner and that in utero Cav1.2 gain-and-loss of function reciprocally regulates the abundance of these neuronal populations. Our findings support the idea that disruption of developmentally regulated calcium channel splicing patterns instructively alters differentiation in the developing cortex, providing important in vivo insights into the pathophysiology of a syndromic ASD.

Keywords: Timothy syndrome; calcium channel splicing; human; human induced pluripotent stem cells; mouse; neuronal differentiation; neuroscience; regenerative medicine; stem cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing / physiology*
  • Animals
  • Autism Spectrum Disorder / genetics
  • Autism Spectrum Disorder / metabolism*
  • Autism Spectrum Disorder / pathology
  • Autistic Disorder
  • Brain / embryology
  • Brain / growth & development
  • Calcium
  • Calcium Channels / genetics
  • Calcium Channels / metabolism*
  • Calcium Channels, L-Type / genetics
  • Calcium Channels, L-Type / metabolism
  • Cell Differentiation / physiology*
  • Cerebral Cortex / embryology
  • Cerebral Cortex / metabolism
  • Exons
  • Gene Expression Regulation, Developmental
  • Humans
  • Induced Pluripotent Stem Cells / metabolism
  • Long QT Syndrome
  • Matrix Attachment Region Binding Proteins / metabolism
  • Mice
  • Models, Animal
  • Mutation
  • Neurogenesis
  • Neurons / cytology
  • Neurons / metabolism
  • RNA Splicing
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism
  • Syndactyly
  • Transcription Factors / metabolism
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism

Substances

  • BCL11B protein, human
  • Bcl11b protein, mouse
  • CACNA1C protein, human
  • Calcium Channels
  • Calcium Channels, L-Type
  • L-type calcium channel alpha(1C)
  • Matrix Attachment Region Binding Proteins
  • Repressor Proteins
  • SATB2 protein, human
  • Transcription Factors
  • Tumor Suppressor Proteins
  • Calcium

Supplementary concepts

  • Timothy syndrome