Itaconate derivative eye drops deploy anti-inflammatory effect in treating dry eye models.

To investigate the therapeutic potential of 4-Octyl itaconate (4-OI), a derivative of the endogenous immunomodulator itaconate (ITA), as a safe and effective anti-inflammatory agent for the treatment of dry eye disease (DED). In vitro cytotoxicity and anti-inflammatory effects of 4-OI were evaluated in hyperosmotic human corneal epithelial cells (HCECs). An in vivo DED model was induced in C57BL/6 mice through environmental controlled chambers. Mice with DED were treated with phosphate buffered saline (PBS), 0.05% cyclosporine A (CsA) eye drops, 4-OI eye drops, or a single 4-OI intraperitoneal injection for 14 days. Corneal epithelial defects and tear secretion were assessed. The safety and underlying molecular mechanisms of topical 4-OI were evaluated using quantitative polymerase chain reaction (qPCR), Western blotting, mRNA sequencing, TdT-mediated dUTP nick-end labeling (TUNEL) assay, and hematoxylin-eosin (H&E) staining. Statistical analyses were performed using independent sample t-tests and one-way ANOVA, with P<0.05 considered statistically significant. Treatment with 4-OI eye drops significantly reduced corneal epithelial defects in DED mice (P<0.0001) compared to the DED control group. Tear secretion was also elevated in the 4-OI eye drop-treated groups. mRNA sequencing revealed significant downregulation of inflammatory pathways, including interleukin (IL)-1 receptor activity, tumor necrosis factor (TNF) signaling, and IL-17 signaling, in the 2 mM 4-OI eye drop group. Molecular assays confirmed a marked reduction in the mRNA and protein expression of IL-1β, IL-17A, TNF-α, and NFKBIZ (IκBζ) in the corneas of 4-OI-treated mice. No significant corneal epithelial apoptosis or systemic toxicity was observed in the 4-OI-treated groups. The ITA derivative 4-OI demonstrates potential as a safe and effective therapeutic option for alleviating DED by suppressing ocular inflammation through the downregulation of IL-1, IL-17, and TNF signaling pathways.