Prostaglandin E ₂ Receptor 2 Modulates Macrophage Activity for Cardiac Repair

Background Prostaglandin E₂ has long been known to be an immune modulator. It is released after tissue injury and plays a role in modulating macrophage activities, which are essential for tissue regeneration. However, the involvement of prostaglandin E₂ receptor 2 ( EP 2)-dependent regulation of macrophages in postischemic heart is unclear. This study aims to evaluate the role of EP 2 in damaged heart. Methods and Results The effect of EP 2 in postischemic heart was evaluated using EP 2-deficient transgenic mice. We demonstrated that cardiac function was worse after myocardial injury on loss of EP 2. Furthermore, EP 2 deficiency also altered proinflammatory response and resulted in a defect in macrophage recruitment to the injured myocardium. Transcriptome analysis revealed that the expression of erythroid differentiation regulator 1 ( Erdr1) was significantly induced in EP 2-deficient macrophages. Knocking down Erdr1 expression restored migration ability of EP 2-deficient cells both in vitro and in vivo. By using a genetic fate-mapping approach, we showed that abolishment of EP 2 expression effectively attenuated cell replenishment. Conclusions The EP 2-dependent signaling pathway plays a critical role in regulating macrophage recruitment to the injured myocardium, thereby exerting a function in modulating the inflammatory microenvironment for cardiac repair.