Abstract
Purpose::
The abnormal differentiation and migration of neural crest cells cause developmental anomalies of the corneal endothelium, iris, ciliary body and angle, leading to developmental glaucoma. It has been known that numerous morphogens for neural crest cells bind to heparan sulfate/ heparan sulfate proteoglycans. In the present study, we investigated the roles of heparan sulfate/ heparan sulfate proteoglycans in differentiation of the neural crest cells during the development of the ocular anterior segment.
Methods::
We disrupted the gene of EXT1 in mice because EXT1 is an indispensable enzyme for the synthesis of heparan sulfate. Using the Cre-loxP approach with Protein 0-Cre (P0-Cre) transgenic mice, EXT1 gene allele was conditionally knocked out in the neural crest cells during embryogenesis. To evaluate the distribution of neural crest cells in the anterior segment of eye, we investigated Cre expression using lacZ-labeling system.
Results::
The Cre was expressed in the corneal stroma and endothelium, Schlemm’s canal, iris and ciliary body. The heparan sulfate-deficient mice exhibited the microphthalmos, dysgenesis in the primitive iris and ciliary body, the failure of lens-cornea separation and optic nerve head agenesis.
Conclusions::
Heparan sulfate deficiency leads to the severe anomaly of the anterior segment. Our present data indicate that heparan sulfate/heparan sulfate proteoglycans are closely involved in the differentiation of neural crest cells.
Keywords: proteoglycans/glycosaminoglycans • development • anterior segment