Abstract
Purpose :
Mutations in ADAMTS10 cause Weill-Marchesani syndrome, characterized by short stature. Previously we showed that a Gly661Arg mutation in ADAMTS10 also causes primary open angle glaucoma (POAG) in dogs, and have proposed dysregulation of transforming growth factor β (TGFβ) signaling as a possible disease mechanism. The purpose of this study is to investigate the role of adamts10 in retinal ganglion cell (RGC) development and TGFβ regulation.
Methods :
Morpholino antisense oligos designed to block translation of adamts10 mRNA, or control morpholinos, were injected into embryos from zebrafish reporter lines with fluorescent protein expression in the retina driven by Brn3a or Pax6b promoters or a Smad3 responsive element. Retinal morphology was examined by H&E staining of sections of embryos fixed in 4% paraformaldehyde and embedded in paraffin. Embryos were examined at 3 days post-fertilization. Specificity of adamts10 morpholino was tested by co-injecting normal ADAMTS10 mRNA and ADAMTS10 mRNA carrying the Gly661Arg mutation found in dogs with POAG.
Results :
The body length of embryos injected with adamts10 morpholino was 49% of controls (p<10-6), while the eye diameter was less affected (82% of controls, p<10-3). Adamts10 morpholino greatly reduced fluorescence in the inner retina and optic nerve driven by RGC-specific Brn3a and Pax6b promoters. Smad3-driven fluorescence, a reporter of TGFβ signaling, was greatly reduced in the eyes of embryos injected with adamts10 morpholino. H&E staining revealed grossly similar retinal morphology in control and adamts10 morphants. Control morpholinos had no effect. Adamts10 morpholino-induced phenotype was rescued by normal ADAMTS10 mRNA, but not by ADAMTS10 mRNA coding the Gly661Arg mutation.
Conclusions :
Similar to Weill-Marchesani syndrome, knockdown of adamts10 in zebrafish causes pronounced reduction of body length. Knockdown of adamts10 results in altered development of RGCs, which may be mediated through TGFβ. An RGC-specific role in POAG for the Gly661Arg mutation of ADAMTS10 is suggested by its inability to compliment phenotypes induced by adamts10 knockdown.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.