Parstatin inhibits viability of human retinal pigment epithelium cells: an in vitro cytotoxicity study

P.S. Gartaganis, M. Cotsiki, E.D. Anastassiou, N.E. Tsopanoglou, M.D. Melachrinou

Department of Pathology, School of Medicine, University of Patras, Patras, Greece. gartaganisp@gmail.com

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• Pharmacology

OBJECTIVE: Parstatin, the N-terminal 41-amino-acid peptide cleaved by thrombin from protease-activated-receptor 1, was shown to be highly effective in preventing ocular angiogenesis and as such it has potential therapeutic applications in ocular neovascular diseases. In the frame of a safety program in preclinical development, we investigated whether parstatin exerts any cytotoxic effect in critical ocular cell populations.

MATERIALS AND METHODS: Human retinal pigment epithelium cell-19 line (ARPE-19) and the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) colorimetric assay were used to investigate parstatin’s effect in cell cultures. Parstatin 24-41 was used as a control peptide which lacks the hydrophobic domain to demonstrate the specificity and the structure-dependent effect of parstatin. Both peptides were used at concentrations ranging from 0.1-30 μM for 24, 48 and 72 hours.

RESULTS: In the presence of parstatin the rate of ARPE-19 cell growth and viability were significantly decreased in a concentration-dependent and time-dependent manner, with an IC50 of approximately 10 μM. When ARPE-19 cells were treated with parstatin 24-41 no inhibitory effect was observed at any concentration or exposure time used.

CONCLUSIONS: Parstatin has a clear detrimental effect on the viability of ARPE-19 cells and raises concerns about its use in the eye because of its possible toxic effects.

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