Abstract
Purpose :
Proteoglycans are a major component of extracellular matrix and have important roles in cell signaling, development and behavior. Proteoglycans are heavily glycosylated proteins that are expressed by almost every mammalian cell. In humans, congenital disorders including bone and skin disease due to proteoglycan deficiency have been reported. We found that proteoglycan deficient retinas of adult mice show retinal folds and pseudorosettes in the outer nuclear layer. In this study we hypothesize that proteoglycans contribute to the development of the outer limiting membrane (OLM) via a thus far unknown mechanism. We propose that impaired OLM development, due to proteoglycan deficiency, results in the formation of retinal folds and pseudorosettes in the outer nuclear layer.
Methods :
UDP-glucose 6-dehydrogenase (Ugdh) is an enzyme involved in proteoglycan synthesis. Transgenic mice which were Ugdh-/- in the peripheral part of the retina were generated. Eyes of adult mice were analyzed by H&E staining and immunofluorescent staining for rhodopsin, N-cadherin and zonula occludens (ZO)-1.
Results :
Ugdh-/- adult mouse retinas show retinal folds and pseudorosettes in the outer nuclear layer. The polarity of the photoreceptors, demonstrated by rhodopsin expression, was altered in the mutants as compared to controls. The OLM in these retinas, determined by altered N-cadherin and ZO-1 expression patterns, was absent in the mutant retinas as compared to control retinas.
Conclusions :
Proteoglycan deficient retinas show retinal folds and pseudorosettes in the outer nuclear layer, in adult mice. Question remains whether it is the lack of OLM which consequently results in the formation of these retinal folds and pseudorosettes. This, together with which proteoglycans may be involved in this process, will be further studied in younger mice.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.