Abstract
Purpose :
We performed RNA sequencing on human lens epithelial cells to identify differentially expressed genes (DEGs) and common disease pathways implicated in steroid-induced versus uveitic cataracts.
Methods :
Between March and July 2023 in Melbourne (VIC, Australia), human anterior lens capsules were prospectively collected during surgery from steroid-induced (n=23) and uveitic cataracts (n=25), and stabilised in RNAlater reagent. The Australian Genome Research Facility performed RNA isolation with RNeasy Mini, and library preparation and sequencing using the Illumina workflow. Quality control was performed with the Agilent 2200 TapeStation. Genes with a log fold change ≥1 and false discovery rate (FDR) <0.05 were defined as differentially expressed and underwent bioinformatic analyses.
Results :
After removal of low abundant genes, 17393 genes remained and were included for analysis. Sex and VisionBlue were corrected for as covariates. Of the 141 DEGs identified, 7 were up-regulated and 134 were down-regulated. Prominent down-regulated gene ontology (GO) terms include inflammatory response (p=6.54E-09), complement activation (p=4.21E-07) and platelet-derived growth factor (PDGF) binding (p=7.05E-05). Prominent down-regulated Kyoto encyclopedia of genes and genomes (KEGG) terms include complement and coagulation cascades (6 genes, gene ratio (GR) 0.11, p=4.91E-06) and TGF-β signalling pathway (5 genes, GR 0.05, p=0.00079). Gene set enrichment analysis (GSEA) shows down-regulation of interferon α response (93 genes, FDR=1.80E-07), interferon γ response (187 genes, FDR=4.50E-06), IL-6/JAK2/STAT3 signalling (70 genes, FDR=0.032), TNF-α/NF-κB signalling (181 genes, FDR=0.036) and complement and coagulation cascades (48 genes, FDR=0.0049).
Conclusions :
Steroid use appears to be a significant and separate variable from uveitis in contributing to cataract pathogenesis. Bioinformatic analyses show the steroid-induced cataract is associated with down-regulated inflammatory and complement responses compared to the uveitic cataract. Its association with PDGF and TGF-β also concurs with past studies that suggest changes to intraocular growth factors underpin steroid-induced cataract pathogenesis. Identification of these pathways may inform the development of novel therapies for the steroid-induced cataract.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.