Development of highly potent EP2 antagonists as novel anti-inflammatory neuroprotectants

Prostaglandin E2 (PGE₂) is a key bioactive lipid mediator that drives neuroinflammation and exacerbates brain tissue damage largely via acting on its receptor EP2 subtype. As such, EP2 has been emerging as an alternative target to cyclooxygenase-2, the inducible enzyme that is responsible for the rate-limiting initial step of PGE₂ biosynthesis, for anti-inflammatory therapy. However, as the current front-running small-molecule antagonist that is highly selective for EP2 and demonstrates extensive neuroprotection and other benefits in models of neuroinflammation and neurotoxicity, compound TG11-77 possesses several limitations, most notably its modest potency and low metabolic stability. Herein, we report a series of EP2-selective antagonists with novel chemical structures, among which compounds CJ-18, CJ-19, and CJ-21 display substantially improved potency and metabolic stability. Molecular docking and molecular dynamics simulations reveal that the new compounds form additional hydrogen bonds within the EP2 binding pocket, which may contribute to their improved potency and enhanced receptor interactions. These new analogs exhibit substantial cytoprotective effects in neuron-glia mixed cultures subjected to oxygen-glucose deprivation, a condition that mimics acute ischemic stroke and reperfusion. In addition, they exert powerful anti-inflammatory actions in mouse primary microglia activated by lipopolysaccharide. Our results support the potential of these drug-like EP2 antagonists to serve as anti-inflammatory neuroprotectants by targeting a specific prostaglandin receptor. Moreover, the findings presented in this work pave the way for more in-depth investigations of these new compounds in clinically relevant models of neuroinflammation-associated conditions, particularly ischemic stroke, where EP2 plays a key pathogenic role.