The Therapeutic Effects of a PEDF-Derived Short Peptide on Murine Experimental Dry Eye Involves Suppression of MMP-9 and Inflammation.

PURPOSE

To evaluate the efficacy of a pigment epithelium-derived factor (PEDF)-derived short peptide 29-mer, on the treatment and prevention of experimental dry eye (EDE).

METHODS

C57BL/6 mice were housed in a low humidity controlled environment chamber for 14 days to induce EDE. The 29-mer was administered topically to their eyes, for treatment or dosing, from the point of housing in the controlled environment chamber. The efficacy of the 29-mer on EDE was evaluated in terms of corneal epithelial integrity, tear secretion, and the density of conjunctival goblet cells. PEDF and inflammatory factors, including tumor necrosis factor-α, IL-1β, IL-6, monocyte chemotactic protein (MCP)-1, matrix metalloproteinase-9, and macrophage infiltration, were examined by real-time polymerase chain reaction, Western blotting, and immunostaining. The involvement of the PEDF receptor/PNPLA2 on the 29-mer effects was evaluated by a specific inhibitor, atglistatin. Rabbit corneal epithelial cells were exposed to hyperosmotic medium to induce inflammatory responses.

RESULTS

The levels of PEDF protein increased in the corneal epithelium of EDE, compared with the nonstressed mice. The 29-mer showed a therapeutic effect on EDE and prevented the development of EDE, accompanied by amelioration of the inflammatory factors. The 29-mer effects of inflammatory relief were dramatically reversed by atglistatin. The 29-mer also suppressed the expression of matrix metalloproteinase-9 and proinflammatory cytokines in rabbit corneal epithelial cells induced by hyperosmolarity.

CONCLUSIONS

Through this animal study, we provide a proof of concept of the anti-inflammatory domain of PEDF having potential to treat dry eye disease.

TRANSLATIONAL RELEVANCE

This study shows the 29-mer has novel potential as an ophthalmic drop treatment for dry eye disease.