Multitargeting of selected prostanoid receptors provides agents with enhanced anti‐inflammatory activity in macrophages

Abstract

A polypharmacologic approach to prostanoid based anti-inflammatory therapeutics was undertaken in order to exploit both the anti- and proinflammatory properties attributed to the various prostanoid receptors. Multitargeting of selected prostanoid receptors yielded a prototype compound, compound 1 (AGN 211377), that antagonizes prostaglandin D2 receptors (DPs) DP1 (49) and DP2 (558), prostaglandin E2 receptors (EPs) EP1 (266) and EP4 (117), prostaglandin F2α receptor (FP) (61), and thromboxane A2 receptor (TP) (11) while sparing EP2, EP3, and prostaglandin I2 receptors (IPs); Kb values (in nanomoles) are given in parentheses. Compound 1 evoked a pronounced inhibition of cytokine/chemokine secretion from lipopolysaccharide or TNF-α stimulated primary human macrophages. These cytokine/chemokines included cluster of designation 40 receptor (CD40), epithelial-derived neutrophil-activating protein 78 (ENA-78), granulocyte colony stimulating factor (G-CSF), granulocyte macrophage colony stimulating factor (GM-CSF), IL-8, IL-18, monocyte chemotactic protein-1 (CCL2) (MCP-1), tissue plasminogen activator inhibitor (PAI-1), and regulated on activation, normal T cell expressed and secreted (RANTES). In contrast, the inhibitory effects of most antagonists selective for a single receptor were modest or absent, and selective EP2 receptor blockade increased cytokine release in some instances. Compound 1 also showed clear superiority to the cyclooxygenase inhibitors diclofenac and rofecoxib. These findings reveal that blockade of multiple prostanoid receptors, with absent antagonism of EP2 and IP, may provide more effective anti-inflammatory activity than global suppression of prostanoid synthesis or highly selective prostanoid receptor blockade. These investigations demonstrate the first working example of prostanoid receptor polypharmacology for potentially safer and more effective anti-inflammatory therapeutics by blocking multiple proinflammatory receptors while sparing those with anti-inflammatory activity.

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

“…Both were ophthalmic disease models: experimental immune uveitis and laser‐induced CNV. Consistent with the anti‐inflammatory effects anticipated from previous studies (1), AGN 211377 exhibited substantial activity in the uveitis model. The marked inhibition of experimental CNV by AGN 211377 exceeded expectations.…”

“…The absence of a profound reduction in CNV by receptor selective antagonists given individually is reminiscent of the results obtained in human macrophages (1). Effects on LPS‐ and TNF‐a‐induced cytokine release from macrophages were achieved by adding permutations of selective antagonists, with a combination of DPi, EP^ EP 4 , FP, and TP producing the greatest effect and equaling that of the single‐molecule pharmacological equivalent AGN 211377 (1). Although cytotoxicity as a result of multiple drugs is readily assessed in cell plates, drug‐drug interactions in vivo are a much more complex problem and especially when combinations of as many as 5 separate drugs are contemplated.…”

“…Thus, AGN 197727 was active at DP 4 , EP 4 , FP, and TP receptors; inactive at EP 2 , EP 3 , and IP receptors; and exhibited only residual antagonist activity at EP 4 receptors. The effects of systemically administered AGN 197727 were subsequently compared with those obtained with AGN 211377 (1) in living animal models.…”

“…The efficacy of AGN 211377 in inhibiting cytokine/ chemokine release from human macrophages was partly related to the absence of an EP 2 receptor antagonism, leaving PGE2 free to exert EP2‐mediated anti‐inflammatory effects (1). A similar mechanism of action operant in CNV would be revealed by an EP 2 antagonist exacerbating laser‐induced angiogenesis.…”

“…The objectives of this study were to determine whether the advantageous polypharmacological antagonism afforded by AGN 211377 in vitro (1) would translate into an in vivo setting by using an animal model where cells of a macrophage lineage would play a significant role, and to use an animal model to uncover additional possible therapeutic utilities for AGN 211377 in a disease process where prostanoids have been implicated. The retina was selected as an important tissue for study because all the major prostanoids are endogenous and are elevated under hyperoxic conditions sufficient to produce retinal angiogenesis (2).…”