Investigating the mechanism of corneal lens development - Project Summary/ Abstract Disturbances in the curvature of the human cornea can lead to visual defects like myopia, hyperopia, astigmatism, or keratoconus. Therefore, understanding how such curved refractive surfaces develop is crucial for preventing or treating these disorders. In this research proposal, I plan to use the Drosophila corneal lens as a model for the human cornea. The fly is an attractive model organism due to its plethora of genetic tools and quick life cycle; and additionally, it about 70% of genes are conserved between humans and flies. The corneal lens is a biconvex ECM structure that focuses light onto the photoreceptor rhabdomeres. A major component of the corneal lens is the polysaccharide chitin, and my preliminary findings suggest that alterations in chitin levels affect corneal lens shape. To explore this idea further, I will use fly genetics, super-resolution and electron microscopy to study the detailed role of chitin in corneal lens morphogenesis (Aim 1; K99). The retina contains a fixed number of non-neuronal central cells which secrete the various corneal lens components and also provide support to the corneal lens. My preliminary data show that an excess of either central or lattice cells affects corneal lens morphology. I will first analyze how varying the numbers of central and lattice cells changes corneal lens architecture, and then using transcriptomics I will identify the genes expressed in these cells during the pupal stage (Aim 2; K99/R00). Central cells also secrete the pseudocone beneath the corneal lens, which is analogous to the mammalian aqueous or vitreous humor. Our previous work identified three proteins in the pseudocone that influence corneal lens shape. Additional pseudocone components will be identified using TurboID to find binding partners of one of these proteins. These as well as transporters and ion channels will be tested for corneal lens shape defects and glaucoma-like phenotypes in flies (Aim 3; R00). This work will provide mechanistic insights into corneal lens morphogenesis, which may be relevant to human corneal development and diseases. To accomplish the proposed research, I will combine my existing skills in developmental genetics, biochemistry and cell biology with new skills learned during my K99 training, including super-resolution microscopy and transcriptomics. During my transition into an independent position, I will solicit advice from my mentors Drs. Jessica Treisman, Gira Bhabha, Holger Knaut, Erika Bach and Hyung Don Ryoo. Their scientific advice on fly genetics, quantitative imaging and transcriptomics along with their experience of grantsmanship, mentoring, lab management, publishing and establishing fruitful collaborations will prove invaluable. My long- term career goal is to head a research laboratory that will investigate the genetic, biophysical, cellular, and molecular regulation of corneal lens shape determination. Although I have made significant progress toward this goal with research experience and publications, I firmly believe that the additional technical and career training proposed during the K99 mentored phase is necessary for my successful transition to independence.
