# Generation of a Novel Col8a2P2A‐CreERT2 Mouse Line Enables Targeted Genetic Manipulation of Corneal Endothelial Cells and Modeling of Endothelial Decompensation

## TL;DR

Scientists created a new mouse model to study corneal endothelial cells, enabling research into their role in eye health and disease.

## Contribution

The creation of the first lineage-specific genetic driver for corneal endothelial cells in mice.

## Key findings

- Col8a2+ cells are essential for Descemet's membrane synthesis and endothelial integrity.
- Ablation of Col8a2+ cells caused phenotypes resembling human corneal dystrophies.
- The Col8a2P2A-CreERT2 mouse line enables targeted genetic manipulation of corneal endothelial cells.

## Abstract

The corneal endothelium is a monolayer of specialized cells that maintains stromal deturgescence and transparency, functions essential for vision. Despite its clinical importance, the developmental origins and homeostatic programs of the endothelium remain poorly understood, in part due to the lack of a lineage‐specific genetic driver. To overcome this limitation, we generated a Col8a2

P2A‐CreERT2
knock‐in mouse line that enables selective genetic manipulations of corneal endothelial cells. Cre activity was validated with reporter alleles and functional importance was assessed by conditional ablation of Col8a2+ cells in adulthood, with phenotypic outcomes evaluated by histology, immunofluorescence, and in vivo imaging. We found that Col8a2

P2A‐CreERT2
drives robust and specific recombination in corneal endothelial cells. Functional assays demonstrated that Col8a2+ cells contribute continuously to Descemet's membrane synthesis and are essential for maintaining endothelial integrity. Ablation disrupted endothelial density and barrier function, resulting in phenotypes resembling human endothelial dystrophies, including features of Fuchs' endothelial corneal dystrophy and posterior polymorphous corneal dystrophy. These findings identify Col8a2+ cells as indispensable regulators of endothelial development, homeostasis, and disease pathogenesis. The Col8a2

P2A‐CreERT2
line provides the first corneal endothelium–specific genetic driver, establishing a platform for mechanistic investigation and therapeutic discovery in endothelial disorders.