Inhibition of 15-prostaglandin dehydrogenase attenuates acetaminophen-induced liver injury via suppression of apoptosis in liver endothelial cells

Hepatic microvascular disruption caused by injury to liver sinusoidal endothelial cells (LSECs) is an aggravating factor for drug-induced liver injury (DILI). It is suggested that prostaglandin E2 2 (PGE2) 2 ) may be able to attenuate LSEC injury. However, it is also known that 15-keto PGE2 , 2 , a metabolite of PGE2 2 produced by 15-prostaglandin dehydrogenase (15-PGDH) that is not a ligand of PGE2 2 receptors, suppresses inflammatory acute liver injury as a ligand of peroxisome proliferator-activated receptor gamma. In this study, we aimed to understand whether 15-PGDH activity is essential for preventing DILI by suppressing hepatic microvascular disruption in a mouse model of acetaminophen (APAP)-induced liver injury. To inhibit 15-PGDH activity prior to APAP-induced LSEC injury, we administered the 15-PGDH inhibitor, SW033291, 1 h before and 3 h after APAP treatment. We observed that LSEC injury preceded hepatocellular injury in APAP administered mice. Hepatic endogenous PGE2 2 levels did not increase up till the initiation of LSEC injury but rather increased after hepatocellular injury. Moreover, hepatic 15-PGDH activity was downregulated in APAP-induced liver injury. The inhibition of 15-PGDH attenuated LSEC injury and subsequently hepatic injury by inhibiting apoptosis in APAP administered mice. Our in vitro studies also suggested that PGE2 2 inhibited APAP-induced apoptosis via the EP4/PI3K pathway in endothelial cells. Therefore, a decrease in 15-PGDH activity would be beneficial for preventing APAP-induced liver injury by attenuating LSEC injury.