The dual pathological roles and targeted therapy of PGE2: from receptor signaling networks to disease microenvironment modulation.

Prostaglandin E2 (PGE2) is a pleiotropic lipid mediator that exerts context-dependent effects via four G protein-coupled receptors (EP1-EP4), playing a pivotal role in the pathogenesis of diverse disorders, including neurodegenerative, cardiovascular, neoplastic, and chronic inflammatory diseases. In this review, we systematically delineate the dualistic functions and mechanisms of PGE2 across these diseases. In neurodegenerative conditions such as Alzheimer's and Parkinson's diseases, PGE2 exacerbates neuroinflammation and neuronal injury in part through EP1 and EP2 in specific cell types, whereas EP4 signaling can confer neuroprotection in certain disease-stage and cellular contexts. Within the tumor microenvironment, PGE2 can drive immunosuppression, angiogenesis, and tumor progression via the EP2/EP4 axis, particularly in colorectal carcinoma, lung adenocarcinoma, and melanoma where this axis is best characterized. In cardiovascular and metabolic diseases, PGE2 exhibits both protective (EP4-mediated) and detrimental (EP3-mediated) effects. Building on this mechanistic framework, we highlight emerging therapeutic strategies designed to overcome the limitations of conventional non-steroidal anti-inflammatory drugs (NSAIDs). These include modulating key enzymes involved in PGE2 synthesis and degradation, developing subtype-selective EP receptor modulators for context-specific intervention, and synergistically targeting downstream pathogenic signaling pathways (e.g., PI3K/Akt/mTOR). By integrating mechanistic and translational perspectives, this review aims to advance next-generation therapies targeting the PGE2 signaling network.