Transcriptome Changes Driving Multiple Regulatory Pathways Involved in TGF-β-Induced Anterior Subcapsular Cataract

Transforming Growth Factor-beta (TGF-β) promotes lens epithelial-mesenchymal transition (EMT) and fibrosis, contributing to anterior subcapsular cataract (ASC) formation. Transgenic mice overexpressing TGF-β1 in the lens have been studied for over three decades, and yet the impact of active TGF-β1-overexpression on the lens epithelial transcriptome is undefined. We have addressed this knowledge gap by examining the gene expression landscape of these unique lens epithelia. High-throughput RNA-sequencing was performed on isolated lens epithelia from three-week-old TGF-β1-overexpression transgenic mice from two independent lines, OVE853 and OVE918, and wild-type mice. Downstream analyses included comparisons with lens datasets (e.g., cataract surgery model) and investigations using various resources/tools (e.g., Gene Ontology, CompBio, and iSyTE). Compared to wild-type murine lens epithelia, 384 differentially expressed genes (DEGs) were commonly identified in the lens of both transgenic lines. Candidates involved in EMT, inflammatory response, extracellular matrix organization, and mechano-sensation were elevated, while those involved in lipid metabolism, Wnt-suppression, Bmp- and Notch-activation were reduced. Comparative analyses with temporal transcriptomes on a mouse cataract surgery model identified overlapping pathological pathways, and some elevated genes, for example, endoplasmic reticulum stress genes, were consistent with human ASC data. This study provides the first comprehensive transcriptomic characterization of two independent TGF-β1 transgenic ASC models and identifies novel candidate downstream genes and pathways associated with TGF-β1 overexpression. All our data is made user-friendly and accessible through iSyTE.