Decreased nuclear Pten in neural stem cells contributes to deficits in neuronal maturation

Mol Autism. 2020 Jun 1;11(1):43. doi: 10.1186/s13229-020-00337-2.

Abstract

Background: PTEN, a syndromic autism spectrum disorder (ASD) risk gene, is mutated in approximately 10% of macrocephalic ASD cases. Despite the described genetic association between PTEN and ASD and ensuing studies, we continue to have a limited understanding of how PTEN disruption drives ASD pathogenesis and maintenance.

Methods: We derived neural stem cells (NSCs) from the dentate gyrus (DG) of Ptenm3m4 mice, a model that recapitulates PTEN-ASD phenotypes. We subsequently characterized the expression of stemness factors, proliferation, and differentiation of neurons and glia in Ptenm3m4 NSCs using immunofluorescent and immunoblotting approaches. We also measured Creb phosphorylation by Western blot analysis and expression of Creb-regulated genes with qRT-PCR.

Results: The m3m4 mutation decreases Pten localization to the nucleus and its global expression over time. Ptenm3m4 NSCs exhibit persistent stemness characteristics associated with increased proliferation and a resistance to neuronal maturation during differentiation. Given the increased proliferation of Ptenm3m4 NSCs, a significant increase in the population of immature neurons relative to mature neurons occurs, an approximately tenfold decrease in the ratio between the homozygous mutant and wildtype. There is an opposite pattern of differentiation in some Ptenm3m4 glia, specifically an increase in astrocytes. These aberrant differentiation patterns associate with changes in Creb activation in Ptenm3m4/m3m4 NSCs. We specifically observed loss of Creb phosphorylation at S133 in Ptenm3m4/m3m4 NSCs and a subsequent decrease in expression of Creb-regulated genes important to neuronal function (i.e., Bdnf). Interestingly, Bdnf treatment is able to partially rescue the stunted neuronal maturation phenotype in Ptenm3m4/m3m4 NSCs.

Conclusions: Constitutional disruption of Pten nuclear localization with subsequent global decrease in Pten expression generates abnormal patterns of differentiation, a stunting of neuronal maturation. The propensity of Pten disruption to restrain neurons to a more progenitor-like state may be an important feature contributing to PTEN-ASD pathogenesis.

Keywords: Autism spectrum disorder; Creb activation; Neural development; Neural stem cells; Neuronal maturation; PTEN mutation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autism Spectrum Disorder / etiology
  • Autism Spectrum Disorder / metabolism
  • Biomarkers
  • Cell Differentiation / genetics*
  • Cell Nucleus
  • Cell Proliferation
  • Cell Self Renewal
  • Cells, Cultured
  • Disease Models, Animal
  • Mice
  • Mice, Knockout
  • Mutation
  • Neural Stem Cells / cytology*
  • Neural Stem Cells / metabolism*
  • Neurogenesis / genetics*
  • Neuroglia / cytology
  • Neuroglia / metabolism
  • Neurons / cytology*
  • Neurons / metabolism*
  • PTEN Phosphohydrolase / genetics*
  • PTEN Phosphohydrolase / metabolism

Substances

  • Biomarkers
  • PTEN Phosphohydrolase
  • PTEN protein, human