MicroRNA Therapy for Dry Eye Disease

We tested the role of microRNA-328 in dry eye disease (DED). Benzalkonium chloride (BAC) has been used to induce DED in animal models. We first demonstrated that both BAC and hyperosmotic stress induced overexpression of miR-328 in corneal cells and then tested whether anti-miR-328 could be a new therapy. BAC was instilled to both eyes of 41 rabbits and 19 mice from day 0 to 21 to induce DED. Animals of each species were divided to receive topical instillation of saline or anti-miR-328 eye drops between day 8 and 21. The DED signs were assessed by corneal fluorescein staining, histological examination, apoptosis of corneal cells, and inflammatory cytokines in rabbit eyes. For mice, only corneal fluorescein staining was assessed for the therapeutic effects. The corneal fluorescein staining scores ranged from 0 of no staining to 4 of coalescent. For the rabbits, the staining score was significantly reduced (P = 0.038) after the 14-day anti-miR-328 treatment (n = 42 eyes), but the score was not improved by saline treatment (n = 40 eyes). Furthermore, rabbit eyes treated with anti-miR-328 had thicker corneal epithelium (P = 9.4 × 10^-5), fewer apoptotic cells in corneal epithelium (P = 0.002), and stroma (P = 0.029) compared with the saline-treated eyes. Anti-miR-328 was more effective than saline to reduce the block of orifices of Meibomian glands, although such an effect was only marginally significant (P = 0.059). Similarly, anti-miR-328 was more effective than saline in reducing corneal staining in mouse eyes (P = 0.005). Overexpression of miR-328 may contribute to DED. Anti-miR-328 protects corneal cells and promotes re-epithelialization for DED treatment.