Transcriptomic analysis of rebamipide-induced gene expression changes toward anti-inflammatory profiles in human conjunctival fibroblasts.

PURPOSE: Excessive conjunctival fibroblast proliferation is a major factor in postoperative scarring following ophthalmic surgery. While Rebamipide is clinically used for dry eye and has anti-inflammatory effects, its direct impact on the transcriptomic profiles and inflammatory signaling of conjunctival fibroblasts remains unclear. We aimed to elucidate the gene expression pathways by which Rebamipide modulates the inflammatory and fibrotic responses of Primary Human Conjunctival Fibroblasts (HCFCs). METHODS: HCFCs were treated with Rebamipide at 0.054 mM (0.002%) or 0.54 mM (0.02%), which represent 1/1000 and 1/100 of the clinical dose (2%), or control media for 24 h. Global transcriptomic changes were analyzed using RNA-seq. Differential expression analysis (FDR < 0.05 and fold-change ≥ 2) was performed, followed by Ingenuity Pathway Analysis (IPA) to identify enriched pathways and upstream regulators. Key findings were validated at the protein level using immunofluorescence and Western blotting. RESULTS: In the functional assay, Rebamipide significantly and dose-dependently increased the metabolic activity and viability of conjunctival fibroblasts at concentrations between 0.054 mM and 1.08 mM, without inducing cytotoxicity. Concurrently, RNA-seq revealed significant dose-dependent gene alterations, with the 0.54 mM group showing the largest change. Rebamipide strongly inhibited pro-inflammatory pathways (TNF, IL1B, IL6) while activating cell cycle regulatory genes (TP53 at 0.054 mM and CDKN1A at 0.54 mM). Notably, the anti-fibrotic effect was associated with the marked downregulation of CSF3 (G-CSF) and other pro-inflammatory cytokines (CXCL6, CCL2, IL11). Mechanistically, the suppression of CSF3 is likely attributable to Rebamipide's modulation of NF-κB signaling, specifically through blockade of p65 nuclear translocation rather than a change in p65 phosphorylation status. Protein and immunofluorescence analyses supported the RNA-seq data, revealing a statistically significant reduction in Total NF-κB protein and a clear blockade of p65 nuclear translocation, which visually corresponded with the reduction in G-CSF expression. CONCLUSION: Rebamipide modulates the gene expression profile of HCFCs toward an anti-inflammatory and anti-fibrotic state, primarily through the downregulation of CSF3 and associated pro-inflammatory cytokines. These findings suggest Rebamipide's potential as a novel topical therapeutic strategy for reducing postoperative scarring and complications in transconjunctival surgery.