Heparan sulfate deficiency leads to Peters anomaly in mice by disturbing neural crest TGF-beta2 signaling

J Clin Invest. 2009 Jul;119(7):1997-2008. doi: 10.1172/JCI38519. Epub 2009 Jun 8.

Abstract

During human embryogenesis, neural crest cells migrate to the anterior chamber of the eye and then differentiate into the inner layers of the cornea, the iridocorneal angle, and the anterior portion of the iris. When proper development does not occur, this causes iridocorneal angle dysgenesis and intraocular pressure (IOP) elevation, which ultimately results in developmental glaucoma. Here, we show that heparan sulfate (HS) deficiency in mouse neural crest cells causes anterior chamber dysgenesis, including corneal endothelium defects, corneal stroma hypoplasia, and iridocorneal angle dysgenesis. These dysfunctions are phenotypes of the human developmental glaucoma, Peters anomaly. In the neural crest cells of mice embryos, disruption of the gene encoding exostosin 1 (Ext1), which is an indispensable enzyme for HS synthesis, resulted in disturbed TGF-beta2 signaling. This led to reduced phosphorylation of Smad2 and downregulated expression of forkhead box C1 (Foxc1) and paired-like homeodomain transcription factor 2 (Pitx2), transcription factors that have been identified as the causative genes for developmental glaucoma. Furthermore, impaired interactions between HS and TGF-beta2 induced developmental glaucoma, which was manifested as an IOP elevation caused by iridocorneal angle dysgenesis. These findings suggest that HS is necessary for neural crest cells to form the anterior chamber via TGF-beta2 signaling. Disturbances of HS synthesis might therefore contribute to the pathology of developmental glaucoma.

Publication types

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

MeSH terms

  • Animals
  • Anterior Chamber / abnormalities*
  • Cell Proliferation
  • Forkhead Transcription Factors / genetics
  • Glaucoma / etiology*
  • Heparitin Sulfate / deficiency
  • Heparitin Sulfate / physiology*
  • Homeodomain Proteins / genetics
  • Integrases / physiology
  • Mice
  • Mice, Inbred C57BL
  • N-Acetylglucosaminyltransferases / physiology
  • Neural Crest / cytology*
  • Neural Crest / physiology
  • Signal Transduction / physiology*
  • Transcription Factors / genetics
  • Transforming Growth Factor beta2 / physiology*
  • Wnt1 Protein / physiology

Substances

  • Forkhead Transcription Factors
  • Foxc1 protein, mouse
  • Homeodomain Proteins
  • Transcription Factors
  • Transforming Growth Factor beta2
  • Wnt1 Protein
  • Wnt1 protein, mouse
  • homeobox protein PITX2
  • Heparitin Sulfate
  • N-Acetylglucosaminyltransferases
  • exostosin-1
  • Cre recombinase
  • Integrases