Signaling networks and transcriptional programs in lens vesicle formation

PROJECT SUMMARY /ABSTRACT Anterior segment dysgenesis (ASD) refers to a spectrum of disorders that affect the front of the eye, including the corneal, iris/ciliary body, and lens. Among the characterized ASD genes, the majority encode transcription factors. However, the upstream signaling events that control these transcription factors are unclear. My long- term goal is to establish the gene regulatory networks that underlies the development of the anterior segment of the eye, in order to identify molecular targets for disease prevention and treatment. The objective of this proposal is to study signaling networks and transcriptional programs in lens development. In particular, I have identified mechanistic target of rapamycin complex 1 (mTORC1) signaling as a novel regulator in lens vesicle formation. And I propose to investigate both the upstream regulators and the downstream targets of mTORC1, using a combination of conditional knockout mouse and primary lens epithelium cell models. My central hypothesis is that Fibroblast Growth Factor (FGF) signaling activates mTORC1 in the lens epithelium (Aim 1), and this mTORC1 signaling controls cell adherence during lens vesicle formation through regulating Wnt signaling (Aim 2). In Aim 1, I will elucidate the mechanism underlying how FGF signaling activates mTORC1 in the lens epithelium. In Aim 2, I will investigate how mTORC1 regulates Wnt signaling and the functional significance of mTORC1-Wnt axis in the formation of adherens junctions in the lens epithelium. In addition, I propose to identify mTORC1 mediated transcriptional programs during lens vesicle formation by Single-cell RNA-sequencing. This proposal is innovative because it identifies a novel regulatory pathway in lens vesicle development. It also links signaling pathways and transcriptional factors to elucidate the mechanism of lens vesicle development and disease pathogenesis. Results from this study are significant in that they are expected to impact the understanding of normal and defective development of the lens vesicle, and have the potential to reveal novel molecular targets for preventive purpose of disease caused by congenital lens defects. The mentored phase of this project will be conducted under the guidance of Drs. Xin Zhang and Carol Mason (Columbia University Irving Medical Center), who are experts in eye development and signaling pathways. Additional advice will be obtained from my scientific advisor Dr. Melinda Duncan and Dr. Peter Sims on aspect of lens development and Single cell RNA-sequencing, respectively. Resources for career development along with the research environment at Columbia University are ideal for my transition into an independent investigator studying signaling mechanisms of eye development and disease.