Inhibition of chemokine MCP-1 with mNOX-E36 reduces scarring in a mouse model of glaucoma filtration surgery

Monocyte-chemoattractant protein 1 (MCP-1), a potent recruiter of monocytes, is increased in tears of glaucoma patients with a greater propensity to scar. mNOX-E36 is a murine-specific analogue of NOX-E36, an anti-MCP-1 L-RNA aptamer that was previously shown to attenuate liver fibrosis in mice. Bleb scarring represents the biggest risk for failure of glaucoma filtration surgery (GFS), a procedure to reduce ocular pressure in glaucoma patients. Anti-fibrotic agents like mitomycin C (MMC) are used to prolong bleb longevity, albeit with significant cytotoxic effects. This study compared the efficacy of mNOX-E36 against MMC on post-operative fibrosis in a murine GFS model. GFS was performed on C57BL/6 mice, followed by subcutaneous or subconjunctival mNOX-E36 administration or MMC treatment. Conjunctival blebs were imaged on Day 1 and Day 7 post-GFS, corresponding to the inflammatory and fibrotic phases respectively. Blebs were harvested for immunofluorescence staining, multiplex cytokine analysis, Western blotting, and RT-qPCR analysis. The effect of mNOX-E36 on RAW264.7 macrophages and conjunctival fibroblasts was also investigated in vitro. Our results established that subconjunctival mNOX-E36 administration is more effective than subcutaneous mNOX-E36 injection in attenuating myeloid cell infiltration, pro-inflammatory cytokine expression, and fibrosis following GFS. Additionally, subconjunctival mNOX-E36 treatment exhibited comparable anti-fibrotic activity to MMC post-GFS. mNOX-E36 also inhibited both macrophage and conjunctival fibroblast activity. Our results thus demonstrate the efficacy of mNOX-E36 compared to clinical standard of care, MMC, in attenuating post-operative inflammation and fibrosis following GFS. NOX-E36 shows promise as an anti-fibrotic adjunctive treatment in GFS.

Glaucoma filtration surgery; MCP-1; Mitomycin C; Spiegelmer; Subconjunctival fibrosis.