CR to demonstrate that CB2 receptors are expressed primarily on Kupffer cells, endothelial cells and neutrophils, but not on hepatocytes (Fig. S7). Consistent with this premise, we showed that MAGL blockade by JZL184, but not 2AG, in isolated hepatocytes exposed to hypoxiareoxygenation attenuated hepatocyte cell death as determined by reduced lactate dehydrogenase (LDH) and ALT release in vitro (Fig. S8). Even so, 2AG therapy of isolated Kupffer cells triggered a partially CB2dependent reduction in TNF levels in response to LPS stimulation (Fig. S9). In contrast, MAGL inhibition had no impact on LPSinduced TNF release (data not shown). Collectively, our final results indicate that both hepatocytes and nonparenchymal cells create 2AG that signals onto CB2 receptors on Kupffer cells, neutrophils, and endothelial cells, when eicosanoids are mainly generated by hepatocytes throughout hepatic I/R. Inactivation of MAGL exerts hepatoprotective effects even when administered after reperfusion We further asked if pharmacological inhibition of MAGL can also be protective when initiated immediately after the induction of hepatic ischemia. Strikingly, we discovered that remedy with JZL184 (Gastroenterology. Author manuscript; accessible in PMC 2014 April 01.NIHPA Author Manuscript NIHPA Author Manuscript NIHPA Author ManuscriptCao et al.Pagemg/kg, i.p.) even for the duration of the reperfusion period resulted in substantial hepatoprotection when administered 1 and three h immediately after induction of hepatic reperfusion (Figs. five, S10, S11). These provocative results recommend that MAGL inhibitors can protect against hepatic I/R injury when administered not simply before, but additionally soon after the liver is exposed to ischemic or hypoxic conditions. Inactivation of MAGL also protects liver harm in murine hepatitis models induced by GalN/LPS or CCl4 Ultimately, we tested regardless of whether inactivation of MAGL can also be hepatoprotective in liver injury models brought on by insults other that hepatic I/R. We found that MAGL blockade with JZL184 substantially protected mice against lethality brought on by liver failure within the galactosamine (GalN) and LPS (GalN/LPS) model (83 lethality in vehicletreated compared to 42 in JZL184treated mice (p=0.04 by Fisher’s exact test)).Morpholin-2-one structure In nonlethal experiments, JZL184 pretreatment drastically reduces GalN/LPSinduced liver damage (Fig.867034-10-4 Chemscene 6A).PMID:24189672 JZL184 pretreatment also properly suppressed CCl4induced hepatic injury (Fig. 6B). Constant with liver I/R model, MAGL inactivation by JZL184 also heightened 2AG signaling and attenuated the GalN/LPS and CCl4induced enhanced hepatic eicosanoid levels and liver injury (Fig. S12). MAGL inactivation by JZL184 significantly attenuated hepatic COX2 mRNA, but not protein levels induced by GalN/LPS or CCl4 (Fig. S13).NIHPA Author Manuscript NIHPA Author Manuscript NIHPA Author ManuscriptDiscussionThere is escalating proof suggesting that CB2 stimulation by pharmacological ligands could represent a promising therapy technique for many liver ailments, as well as other disorders ranging from gastrointestinal, kidney, neurodegenerative, autoimmune diseases to pain and cancer8. Activation of CB2 signaling affords protection in hepatic I/R by attenuation of acute proinflammatory responses orchestrated by activated endothelial and Kupffer cells, also as by inhibition of delayed neutrophil infiltration and neutrophilmediated liver injury8. Pharmacological or genetic inactivation of COX2 has also been shown to protect the liver against injury by suppressing infl.
