Topical Administration of 0.3% Tofacitinib Suppresses M1 Macrophage Polarization and Allograft Corneal Rejection by Blocking STAT1 Activation in the Rat Cornea

PURPOSE: M1 macrophages can promote corneal allograft rejection (CGR). Inhibiting M1 macrophage polarization by the JAK/STAT1 pathway may be a new strategy to prevent CGR. Tofacitinib, a potent pan-JAK inhibitor, can inhibit JAK/STAT activation. Here, we investigated the inhibitory effects of tofacitinib on M1 macrophage polarization and its therapeutic effect on rat CGR. METHODS: Corneal allograft transplantation was performed and administrated with 0.3% tofacitinib in rats. The corneal allografts were assessed clinically. The corneas were detected for M1 macrophages, lymphatic vessels, and inflammatory cytokine expression using immunohistochemistry and real-time polymerase chain reaction (PCR). Dendritic cells (DCs) in ipsilateral cervical lymph nodes were detected by flow cytometry. The effect and mechanism of tofacitinib on macrophages were explored by real-time PCR, enzyme-linked immunoassay, and western blot analysis in vitro. RESULTS: The results showed that topical administration of 0.3% tofacitinib significantly prolonged corneal graft survival. Tofacitinib-treated corneal allografts displayed a proportionate decrease in M1 macrophages and reduced lymphatic vessel density with fewer DCs in rat ipsilateral cervical lymph nodes. Tofacitinib reduced the mRNA expression of inflammatory cytokines, including iNOS, MCP-1, TNF-α, IL-6, IL-1β, and VEGF-C, and inhibited STAT1 activation in rat corneal grafts. In addition, tofacitinib suppressed M1 macrophage polarization via STAT1 activation after IFN-γ and lipopolysaccharide stimulation in vitro. CONCLUSIONS: Tofacitinib could suppress M1 macrophage polarization and subsequently delay CGR by inhibiting STAT1 activation. The data indicate that tofacitinib is an effective drug for CGR. TRANSLATIONAL RELEVANCE: This study provided evidence that topical administration of 0.3% tofacitinib may be a novel clinical strategy to prevent CGR.