Monoacylglycerol lipase (MAGL) inhibition attenuates acute lung injury in mice

Regulation of inflammation by cannabinoids, the endocannabinoids 2-arachidonoyl-glycerol and arachidonoyl-ethanolamide, and their metabolites

2-Arachidonoyl-glycerol (2-AG) and arachidonyl-ethanolamide (AEA) are endocannabinoids that have been implicated in many physiologic disorders, including obesity, metabolic syndromes, hepatic diseases, pain, neurologic disorders, and inflammation. Their immunomodulatory effects are numerous and are not always mediated by cannabinoid receptors, reflecting the presence of an arachidonic acid (AA) molecule in their structure, the latter being the precursor of numerous bioactive lipids that are pro- or anti-inflammatory. 2-AG and AEA can thus serve as a source of AA but can also be metabolized by most eicosanoid biosynthetic enzymes, yielding additional lipids. In this regard, enhancing endocannabinoid levels by using endocannabinoid hydrolysis inhibitors is likely to augment the levels of these lipids that could regulate inflammatory cell functions. This review summarizes the metabolic pathways involved in the biosynthesis and metabolism of AEA and 2-AG, as well as the biologic effects of the 2-AG and AEA lipidomes in the regulation of inflammation.

CB2R orchestrates fibrogenesis through regulation of inflammatory response during the repair of skeletal muscle contusion

Skeletal muscle injuries repair typically is an overlapping event between inflammation and tissue repair. Our previous study has demonstrated that activation of cannabinoid receptor type 2 (CB2R) by JWH-133 alleviates fibrosis in the repair of rat skeletal muscle contusion. Meanwhile, accumulated data show that CB2R stimulation exerts anti-inflammatory property in sepsis and cystitis. However, the effects of CB2R on inflammatory cytokines in response to the repair of skeletal muscle contusion are still unknown. In this study, we used selective agonist or antagonist of CB2R to observe the role of CB2R on inflammation and fibrogenesis during the repair of contused skeletal muscles in rats. Our results revealed that treatment with Gp1a, a selective CB2R agonist, significantly decreased the infiltration of neutrophils and macrophages, the expression of pro-inflammatory cytokines MCP-1, TNF-α, IL-1β and IL-6, the expression of pro-fibrotic cytokines IL-4, IL-13, TGF-β and P-Smad3 while increased anti-fibrotic cytokine IL-10 production as compared with Vehicle. The opposite results were observed in the CB2R inhibition group with AM630. Our study demonstrated that CB2R orchestrates fibrogenesis through regulation of inflammatory response during the repair of skeletal muscle contusion.

The Potential of Inhibitors of Endocannabinoid Metabolism for Drug Development: A Critical Review

The endocannabinoids anandamide and 2-arachidonoylglycerol are metabolised by both hydrolytic enzymes (primarily fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MGL)) and oxygenating enzymes (e.g. cyclooxygenase-2, COX-2). In the present article, the in vivo data for compounds inhibiting endocannabinoid metabolism have been reviewed, focussing on inflammation and pain. Potential reasons for the failure of an FAAH inhibitor in a clinical trial in patients with osteoarthritic pain are discussed. It is concluded that there is a continued potential for compounds inhibiting endocannabinoid metabolism in terms of drug development, but that it is wise not to be unrealistic in terms of expectations of success.

Chemical approaches to therapeutically target the metabolism and signaling of the endocannabinoid 2-AG and eicosanoids

The endocannabinoid system, most popularly known as the target of the psychoactive component of marijuana, Δ(9)-tetrahydrocannabinol (THC), is a signaling network that modulates a diverse range of physiological processes including nociception, behavior, cognitive function, appetite, metabolism, motor control, memory formation, and inflammation. While THC and its derivatives have garnered notoriety in the eyes of the public, the endocannabinoid system consists of two endogenous signaling lipids, 2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (anandamide), which activate cannabinoid receptors CB1 and CB2 in the nervous system and peripheral tissues. This review will focus on the recent efforts to chemically manipulate 2-AG signaling through the development of inhibitors of the 2-AG-synthesizing enzyme diacylglycerol lipase (DAGL) or the 2-AG-degrading enzyme monoacylglycerol lipase (MAGL), and assessing the therapeutic potential of DAGL and MAGL inhibitors in pain, inflammation, degenerative diseases, tissue injury, and cancer.

Anandamide attenuates Th-17 cell-mediated delayed-type hypersensitivity response by triggering IL-10 production and consequent microRNA induction

Endogenous cannabinoids [endocannabinoids] are lipid signaling molecules that have been shown to modulate immune functions. However, their role in the regulation of Th17 cells has not been studied previously. In the current study, we used methylated Bovine Serum Albumin [mBSA]-induced delayed type hypersensitivity [DTH] response in C57BL/6 mice, mediated by Th17 cells, as a model to test the anti-inflammatory effects of endocannabinoids. Administration of anandamide [AEA], a member of the endocannabinoid family, into mice resulted in significant mitigation of mBSA-induced inflammation, including foot pad swelling, cell infiltration, and cell proliferation in the draining lymph nodes [LN]. AEA treatment significantly reduced IL-17 and IFN-γ production, as well as decreased RORγt expression while causing significant induction of IL-10 in the draining LNs. IL-10 was critical for the AEA-induced mitigation of DTH response inasmuch as neutralization of IL-10 reversed the effects of AEA. We next analyzed miRNA from the LN cells and found that 100 out of 609 miRNA species were differentially regulated in AEA-treated mice when compared to controls. Several of these miRNAs targeted proinflammatory mediators. Interestingly, many of these miRNA were also upregulated upon in vitro treatment of LN cells with IL-10. Together, the current study demonstrates that AEA may suppress Th-17 cell–mediated DTH response by inducing IL-10 which in turn triggers miRNA that target proinflammatory pathways.

Activity-based proteomic and metabolomic approaches for understanding metabolism

There are an increasing number of human pathologies that have been associated with altered metabolism, including obesity, diabetes, atherosclerosis, cancer, and neurodegenerative diseases. Most attention on metabolism has been focused on well-understood metabolic pathways and has largely ignored most of the biochemical pathways that operate in (patho)physiological settings, in part because of the vast landscape of uncharacterized and undiscovered metabolic pathways. One technology that has arisen to meet this challenge is activity-based protein profiling (ABPP) that uses activity-based chemical probes to broadly assess the functional states of both characterized and uncharacterized enzymes. This review will focus on how ABPP, coupled with inhibitor discovery platforms and functional metabolomic technologies, have led to discoveries that have expanded our knowledge of metabolism in health and disease.