Abstract
Glaucoma is associated with ocular hypertension, and lowering intraocular pressure is the primary objective of current therapies. Recent studies have established a key role for Schlemm’s canal endothelium in this pressure increase and have shown that it has a unique, lymphatic-like hybrid phenotype characterized by expression of the lymphatic transcription factor PROX1. However, the functional importance of this hybrid phenotype in the adult canal remains unclear, as long-term studies have been limited by systemic requirements for lymphatic gene expression and a lack of Schlemm’s canal–specific animal models. Here, we designed and validated a strategy using 4OH-tamoxifen-loaded nanocarriers to generate targeted, Schlemm’s canal specific Prox1 knockout mice that specifically lacked lymphatic characteristics in the canal endothelium. Within 4 weeks, intraocular pressure was significantly elevated, and ocular hypertension was maintained for at least 24 weeks. Unlike lymphatic vessels, which degenerate following Prox1 deletion, Schlemm’s canal persisted but reverted to a less functional vein-like phenotype with no change in size or morphology. Together, these findings demonstrate the utility of nanocarrier-mediated tamoxifen delivery and establish the importance of the Schlemm’s canal lymphatic-like phenotype in intraocular pressure regulation, providing targets for future glaucoma therapies and a mouse model of adult-onset ocular hypertension.
Authors
Sofia Lara Ochoa, Hoi-Lam Li, Hyeohn Kim, Zihang Yan, Natalia C. Mendonca, Pan Liu, Hyunjoo J. Lee, Michael P. Vincent, Sultan Almunif, Hao F. Zhang, Haiyan Gong, Evan A. Scott, Mark Johnson, Benjamin R. Thomson
Figure 6
FLT4 is not required for Schlemm’s canal maintenance or IOP homeostasis in adult mice.
