Moxifloxacin modifies corneal fibroblast‐to‐myofibroblast differentiation

Background and Purpose Fibroblast‐to‐myofibroblast differentiation is associated with scarring, an important issue in corneal surgery. Moxifloxacin ( MOX ), commonly applied to prevent post‐operative infection, would benefit more if it modifies fibroblast‐to‐myofibroblast differentiation other than antimicrobial activity. Our purpose was to explore whether MOX has anti‐fibrotic effect in human corneal fibroblasts ( HCFs ). Experimental Approach HCFs were incubated in MOX ‐containing medium concurrently with TGF ‐β1 (co‐treatment), before (pretreatment) or after (post‐treatment) adding TGF ‐β1. HCF contractility was evaluated with a type I collagen gel contraction assay. Expression of α‐smooth muscle actin (α‐ SMA ), S mad2, phospho‐ S mad2‐ S er467, S mad4 and S mad7 was determined by immunoblotting. Formation of α‐ SMA ‐positive filaments and distribution of active S mad2 were observed under confocal microscopy. Expression of TGF ‐β receptor types I ( TGFBR 1) and II ( TGFBR 2) was assessed with flow cytometry. Key Results MOX did not affect gel contractility or α‐ SMA filament formation in HCFs without TGF ‐β1 stimulation. MOX did, however, retard HCF ‐containing gel contractility and α‐ SMA filament formation following TGF ‐β1 stimulation in the pretreatment and co‐treatment groups but not in the post‐treatment group. MOX blocked the expression of S mad2, phospho‐ S mad2‐ S er467 and TGFBR 1 under TGF ‐β1 incubation. Additionally, MOX enhanced S mad7 expression in TGF ‐β1‐incubated HCFs , but did not interfere with TGF ‐β‐triggered S mad2 nuclear translocation or S mad4 expression. Conclusions and Implications MOX inhibited TGF ‐β‐induced fibroblast‐to‐myofibroblast differentiation via blocking TGFBR 1 and enhancing S mad7 expression. MOX should be used before or during surgery to achieve these effects. These results suggest a de novo mechanism by which MOX participates in corneal wound healing.