In vivo studies validating multitargeting of prostanoid receptors for achieving superior anti-inflammatory effects

Abstract

The purpose of these studies was to test the hypothesis that a selected polypharmacological approach for treating the prostanoid-mediated component of inflammatory diseases would produce a therapeutic effect superior to global inhibition of prostaglandin (PG) biosynthesis by aspirin-like drugs. The compound studied was AGN 211377, which had been previously shown to produce a superior effect on cytokine release from human macrophages compared with cyclooxygenase (COX) inhibitors. AGN 211377 antagonizes prostanoid prostaglandin D₂ (DP)₁, DP₂, prostaglandin E₂ (EP)₁, EP₄, prostaglandin F_2α, and thromboxane A₂ receptors but not anti-inflammatory EP₂, prostaglandin I₂, or EP₃ receptors. Established rodent models of ocular inflammatory diseases were used to determine therapeutic effects in living animals. The drugs were administered systemically after predetermination of their blood levels to ensure bioavailability at an appropriate dose level. Whereas compounds selective for a single prostanoid receptor typically exhibited modest but statistically significant inhibition, AGN 211377 profoundly inhibited S-antigen-induced uveitis and laser-induced retinal neovascularization. Consistent with previous polypharmacological studies on chemokine/cytokine release from human macrophages, the prostanoid EP₁ receptor played a permissive role in suppressing neovascularization and inflammation in vivo Comparing AGN 211377 with a close structural congener lacking EP₁ antagonism (AGN 197727), AGN 197727 was much less active than AGN 211377, but pronounced anti-inflammatory and angiostatic effects were achieved by adding the EP₁ antagonist compound (SC-51322) to AGN 197727 in the systemic dosing regimen. Further, AGN 211377 produced superior anti-inflammatory activity compared with the nonsteroidal anti-inflammatory agent ketorolac. These results indicate the value of using a polypharmacological approach in the design of novel therapeutic agents in preference to compounds targeting a single receptor or enzyme. A compound such as AGN 211377 may represent more effective therapy than COX inhibitors in treating uveitis and ocular diseases where neovascularization is a significant part of the pathology.-Woodward, D. F., Wang, J. W., Ni, M., Bauer, A., Martos, J. L., Carling, R. W., Poloso, N. J. In vivo studies validating multitargeting of prostanoid receptors for achieving superior anti-inflammatory effects.

Keywords: antagonist; neovascularization; polypharmacology; retina; uveitis.