Targeting the mPGES-PGE-EP4 pathway with MF63, MK886, and Grapiprant as a potential therapeutic strategy for Escherichia coli-induced endometritis in dairy cows.

Escherichia coli (E. coli) is the primary causative agent of endometritis in dairy cows. Antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs) are the main treatments; however, prolonged antibiotic use promotes bacterial resistance, while NSAIDs can delay ovulation and impair reproduction. Safer and more effective alternative therapies are needed to control infection while minimizing adverse effects. In the bovine uterine microenvironment, prostaglandin E (PGE) plays a key role by activating the EP4 receptor. However, the therapeutic potential of microsomal prostaglandin E synthase-1 (mPGES-1) inhibitor (MF63), mPGES-1 regulator (MK886) and the EP4 receptor antagonist (Grapiprant) in bacterial endometritis remains unclear. This study investigates the therapeutic potential of MF63, MK886 and Grapiprant in mitigating E. coli-induced endometritis in dairy cow. Molecular docking showed that MF63 and MK886 efficiently bind to mPGES-1, while Grapiprant stably binds to the EP4 receptor. Additionally, these inhibitors significantly suppressed PGE secretion in E. coli-infected bovine endometrial tissues. Hematoxylin and eosin staining and immunofluorescence analysis demonstrated that MF63, MK886, and Grapiprant significantly reduced E. coli-induced tissue damage and the expression of damage-associated molecular patterns, such as HMGB-1 and HABP-2. Furthermore, these treatments decreased pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) and the chemokine IL-8 while increasing IL-10 expression. In conclusion, targeting the mPGES-PGE-EP4 pathway may offer a safer, more effective alternative for managing E. coli-induced endometritis in dairy cows.