Modeling Smith-Lemli-Opitz syndrome with induced pluripotent stem cells reveals a causal role for Wnt/β-catenin defects in neuronal cholesterol synthesis phenotypes

Nat Med. 2016 Apr;22(4):388-96. doi: 10.1038/nm.4067. Epub 2016 Mar 21.

Abstract

Smith-Lemli-Opitz syndrome (SLOS) is a malformation disorder caused by mutations in DHCR7, which impair the reduction of 7-dehydrocholesterol (7DHC) to cholesterol. SLOS results in cognitive impairment, behavioral abnormalities and nervous system defects, though neither affected cell types nor impaired signaling pathways are fully understood. Whether 7DHC accumulation or cholesterol loss is primarily responsible for disease pathogenesis is also unclear. Using induced pluripotent stem cells (iPSCs) from subjects with SLOS, we identified cellular defects that lead to precocious neuronal specification within SLOS derived neural progenitors. We also demonstrated that 7DHC accumulation, not cholesterol deficiency, is critical for SLOS-associated defects. We further identified downregulation of Wnt/β-catenin signaling as a key initiator of aberrant SLOS iPSC differentiation through the direct inhibitory effects of 7DHC on the formation of an active Wnt receptor complex. Activation of canonical Wnt signaling prevented the neural phenotypes observed in SLOS iPSCs, suggesting that Wnt signaling may be a promising therapeutic target for SLOS.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • Animals
  • Cell Differentiation / genetics*
  • Cholesterol / biosynthesis
  • Cholesterol / metabolism
  • Dehydrocholesterols / metabolism
  • Humans
  • Induced Pluripotent Stem Cells / metabolism*
  • Induced Pluripotent Stem Cells / transplantation
  • Mice
  • Mutation
  • Neurons / metabolism
  • Oxidoreductases Acting on CH-CH Group Donors / genetics
  • Oxidoreductases Acting on CH-CH Group Donors / metabolism
  • Smith-Lemli-Opitz Syndrome / genetics*
  • Smith-Lemli-Opitz Syndrome / metabolism
  • Smith-Lemli-Opitz Syndrome / pathology
  • Wnt Signaling Pathway / genetics*

Substances

  • Dehydrocholesterols
  • Cholesterol
  • 7-dehydrocholesterol
  • Oxidoreductases Acting on CH-CH Group Donors
  • 7-dehydrocholesterol reductase