Abstract
Purpose :
Vernal keratoconjunctivitis (VKC) is a recurrent bilateral ocular allergic inflammatory disease characterized by severe type 2 inflammation and tissue remodeling. Using a transcriptomic analysis, we examined the epithelial conjunctival gene expression related to the barrier function and the potential evolution to epithelial mesenchymal transition (EMT) in VKC.
Methods :
Cells from conjunctival imprints from active VKC patients (n=15) and normal subjects (CT; n=5) were collected and their RNA isolated with Qiagen RNeasy Mini kit. 10 ng of RNA were processed with GeneChip Pico Reagent kit prior to a 9-cylcle PCR amplification and reverse transcription. Final cDNA was analyzed with Affymetrix Clarion S arrays system. Differential expression (DE) analysis included comparisons between VKC, VKC-subgroups and CT. Enrichment analyses on DE genes (adjusted p <0.05 and absolute log2 fold change >1) and regression analysis genes (p value<0.05) was performed using Gene Ontology Biological Process (GOBP) and Reactome.
Results :
The difference between VKC and CT showed 333 probes (325 genes) significantly DE: 92 over-expressed and 241 down-regulated. Considering all VKC samples vs CT, 169 out of 325 identifiers were found in Reactome, where 646 pathways were hit by at least one of them. In tarsal VKC several GOBP were related to tissue remodeling, cytokine production and B cells regulation while in limbal VKC the ribonucleoprotein complex biogenesis was the most represented. We found a significant overexpression of MUC1, MUC3A, MUC4, MUC16, LGALS3BP, KRT23, GJB2, TJP1, PCDH, a significant reduced expression of CLDN8, CLDN34, CLDND1, CTNNAL1, SPINK2, EDIL3, and LUM. Many other genes of the cadherin, cingulin, occludin, MARVEL domain, lectin and actin families were either significantly up- or downregulated. We found up-regulation of epithelial marker E-cadherin, a non-increased expression of genes encoding for N-cadherin, vimentin and squamous cell carcinoma antigen (SCCA/SERPINB3) as EMT markers and a significant downregulation of the transcription factors required for EMT, SNAI-1, SNAI-2 and TWIST.
Conclusions :
Several biological processes are associated to the pathogenesis of VKC in addition to an epithelial barrier remodeling. EMT is inhibited in VKC, explaining the finding that the majority of VKC patients, after the resolution of the disease, have mild cicatricial consequences.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.