Abstract
Purpose :
Glaucoma is a progressive and irreversible disease affecting the optic nerve, characterized by high clinical and genetic heterogeneity. Our preliminary studies on childhood glaucoma revealed a significant mutational burden in different extracellular matrix metalloproteinase-related genes, including as ADAMTSL4 and CPAMD8. Based on this data, we hypothesize a complex inheritance of this type of glaucoma, where the additive partial functional disruption of various extracellular matrix genes might contribute to its pathogenesis. This study employs zebrafish as an animal model to investigate the potential role of combined partial loss-of-function of adamtsl4 and cpamd8 on the development of the ocular anterior segment and childhood glaucoma.
Methods :
Immunohistochemistry was used to assess the expression of adamtsl4 in zebrafish ocular tissues. Double heterozygous zebrafish, carrying both adamtsl4 and cpamd8 loss-of-function alleles, were generated through the crossbreeding of two different zebrafish lines, previously established in our laboratory as knockout models for either adamtsl4 or cpamd8. Optical microscopy was utilized to analyze the morphology and volume of the anterior chamber assuming its spherical cap structure.
Results :
Immunohistochemical analysis revealed the presence of adamtsl4 protein in the anterior segment (cornea, lens epithelium and periocular mesenchyme) and retina (outer and inner plexiform layers) of wild-type larvae (6 dpf). The single heterozygous loss-of-function of these genes resulted in wild type-like ocular phenotypes while the combined heterozygous loss-of-function of these two genes led to developmental alterations in the anterior segment, resulting in a significant 20% reduction of the ocular anterior chamber volume.
Conclusions :
These results support the notion of a functional interaction of adamtsl4 and cpamd8 in zebrafish and suggests a potential presence of his interaction in the human eye. Furthermore, these findings reveal that the combined effect of partial loss-of-function of these two genes leads to alterations in the anterior chamber of zebrafish, indicating that this mechanism might contribute to the genetic susceptibility to early-onset glaucoma. Further work is required to confirm these findings.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.