mTOR/Autophagy//NF-κB Axis Drives Benzalkonium Chloride-Induced Inflammatory Response in Corneal Epithelial Cells

PURPOSE: Benzalkonium chloride (BAK), a quaternary ammonium antimicrobial agent widely utilized in ophthalmic formulations, is associated with chronic ocular surface toxicity. BAK induces corneal epithelial inflammation and autophagic impairment, yet their interrelationship remains unclear. METHODS: Mouse corneal epithelial cell lines (MCECs) were subjected to short-term BAK exposure (10-20 μg/mL, 15 min + 8 h recovery). TLR4/MyD88/NF-κB pathway activation and proinflammatory cytokines (Il-1α, Il-1β, Il-6) were assessed. Autophagic flux was evaluated via LC3-II/I ratio, p62 accumulation, GFP-RFP-LC3 autolysosome formation assay, and lysosomal function. Pharmacological interventions with rapamycin (mTOR blockade) and TAK-242 (TLR4 inhibition) were used to dissect pathway interactions. RESULTS: Short-term BAK exposure dose-dependently activated the TLR4/MyD88/NF-κB pathway and elevated proinflammatory cytokines. Concurrently, BAK inhibited autophagic flux through mTOR hyperactivation, evidenced by reduced LC3-II/I ratio, p62 accumulation, impaired autolysosome formation, and lysosomal dysfunction. Both rapamycin and TAK-242 significantly attenuated BAK-induced MyD88/NF-κB activation and inflammation. Critically, BAK activates parallel TLR4-MyD88 and mTOR pathways that synergistically amplify NF-κB signaling. CONCLUSIONS: These results unveil mTOR as a therapeutic target for mitigating BAK-induced corneal damage, thereby proposing mTOR suppression or autophagic activation as viable interventions for BAK-associated ocular surface disorders. Particularly at lower concentration (0.001%) and shorter exposure (15 min) of BAK.