Endocannabinoids acting on the cannabinoid-1 receptor (CB1R) or ghrelin acting on its receptor (GHS-R1A) both promote alcohol-seeking behavior, but an interaction between the two signaling systems ...has not been explored. Here, we report that the peripheral CB1R inverse agonist JD5037 reduces ethanol drinking in wild-type mice but not in mice lacking CB1R, ghrelin peptide or GHS-R1A. JD5037 treatment of alcohol-drinking mice inhibits the formation of biologically active octanoyl-ghrelin without affecting its inactive precursor desacyl-ghrelin. In ghrelin-producing stomach cells, JD5037 reduced the level of the substrate octanoyl-carnitine generated from palmitoyl-carnitine by increasing fatty acid β-oxidation. Blocking gastric vagal afferents abrogated the ability of either CB1R or GHS-R1A blockade to reduce ethanol drinking. We conclude that blocking CB1R in ghrelin-producing cells reduces alcohol drinking by inhibiting the formation of active ghrelin and its signaling via gastric vagal afferents. Thus, peripheral CB1R blockade may have therapeutic potential in the treatment of alcoholism.
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•CB1R and ghrelin work together to promote alcohol intake via a gut-brain axis•Alcohol intake is inhibited by CB1R blockade, but only when ghrelin signaling is intact•Inhibition of peripheral CB1R reduces plasma levels of biologically active ghrelin•CB1R blockade promotes the degradation of the substrate needed to activate ghrelin
Endocannabinoids and ghrelin are both implicated in promoting alcohol intake. Godlewski et al. show that cannabinoid-1 receptor (CB1R) signaling in ghrelin-producing stomach cells modulates the formation of biologically active octanoyl-ghrelin which then acts via gastric vagal afferents to promote alcohol consumption. They further show that peripherally-restricted pharmacological inhibition of CB1R reduces ethanol drinking in mice.
N-acylethanolamines (NAEs), which include the endocannabinoid anandamide, represent an important family of signaling lipids in the brain. The lack of chemical probes that modulate NAE biosynthesis in ...living systems hamper the understanding of the biological role of these lipids. Using a high-throughput screen, chemical proteomics and targeted lipidomics, we report here the discovery and characterization of LEI-401 as a CNS-active N-acylphosphatidylethanolamine phospholipase D (NAPE-PLD) inhibitor. LEI-401 reduced NAE levels in neuroblastoma cells and in the brain of freely moving mice, but not in NAPE-PLD KO cells and mice, respectively. LEI-401 activated the hypothalamus-pituitary-adrenal axis and impaired fear extinction, thereby emulating the effect of a cannabinoid CB
receptor antagonist, which could be reversed by a fatty acid amide hydrolase inhibitor. Our findings highlight the distinctive role of NAPE-PLD in NAE biosynthesis in the brain and suggest the presence of an endogenous NAE tone controlling emotional behavior.
We performed integrative network analyses to identify targets that can be used for effectively treating liver diseases with minimal side effects. We first generated co‐expression networks (CNs) for ...46 human tissues and liver cancer to explore the functional relationships between genes and examined the overlap between functional and physical interactions. Since increased de novo lipogenesis is a characteristic of nonalcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC), we investigated the liver‐specific genes co‐expressed with fatty acid synthase (FASN). CN analyses predicted that inhibition of these liver‐specific genes decreases FASN expression. Experiments in human cancer cell lines, mouse liver samples, and primary human hepatocytes validated our predictions by demonstrating functional relationships between these liver genes, and showing that their inhibition decreases cell growth and liver fat content. In conclusion, we identified liver‐specific genes linked to NAFLD pathogenesis, such as pyruvate kinase liver and red blood cell (PKLR), or to HCC pathogenesis, such as PKLR, patatin‐like phospholipase domain containing 3 (PNPLA3), and proprotein convertase subtilisin/kexin type 9 (PCSK9), all of which are potential targets for drug development.
Synopsis
Integrative network analyses identify liver‐specific drug targets that can be used to effectively treat liver diseases including nonalcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC).
Co‐expression networks are generated for 46 human tissues and liver cancer.
Genes that are co‐expressed with fatty acid synthase (FASN) only in liver tissue are identified.
Inhibition of liver‐specific genes decreases liver fat and cell growth.
Liver‐specific genes can be targeted in order to treat NAFLD and HCC.
Integrative network analyses identify liver‐specific drug targets that can be used to effectively treat liver diseases including nonalcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC).
High-fat diet (HFD)–induced obesity and insulin resistance are associated with increased activity of the endocannabinoid/CB ₁ receptor (CB ₁R) system that promotes the hepatic expression of lipogenic ...genes, including stearoyl-CoA desaturase-1 (SCD1). Mice deficient in CB ₁R or SCD1 remain lean and insulin-sensitive on an HFD, suggesting a functional link between the two systems. The HFD-induced increase in the hepatic levels of the endocannabinoid anandamide i.e., arachidonoylethanolamide (AEA) has been attributed to reduced activity of the AEA-degrading enzyme fatty acid amide hydrolase (FAAH). Here we show that HFD-induced increased hepatic AEA levels and decreased FAAH activity are absent in SCD1 ⁻/⁻ mice, and the monounsaturated fatty acid (MUFA) products of SCD1, palmitoleic and oleic acid, inhibit FAAH activity in vitro at low micromolar concentrations. HFD markedly increases hepatic SCD1 activity in WT mice as well as in CB ₁R ⁻/⁻ mice with transgenic reexpression of CB ₁R in hepatocytes, but not in global CB ₁R ⁻/⁻ mice. Treatment of HFD-fed mice with the SCD1 inhibitor A939572 prevents the diet-induced reduction of hepatic FAAH activity, normalizes hepatic AEA levels, and improves insulin sensitivity. SCD1 ⁻/⁻ mice on an HFD remain insulin-sensitive, but develop glucose intolerance and insulin resistance in response to chronic treatment with the FAAH inhibitor URB597. An HFD rich in MUFA or feeding mice pure oleic acid fail to inhibit hepatic FAAH activity. We conclude that MUFAs generated via SCD1 activity, but not diet-derived MUFAs, function as endogenous FAAH inhibitors mediating the HFD-induced increase in hepatic AEA, which then activates hepatic CB ₁R to induce insulin resistance.
Alcohol consumption is associated with gut dysbiosis, increased intestinal permeability, endotoxemia, and a cascade that leads to persistent systemic inflammation, alcoholic liver disease, and other ...ailments. Craving for alcohol and its consequences depends, among other things, on the endocannabinoid system. We have analyzed the relative role of central vs. peripheral cannabinoid CB1 receptors (CB1R) using a "two-bottle" as well as a "drinking in the dark" paradigm in mice. The globally acting CB1R antagonist rimonabant and the non-brain penetrant CB1R antagonist JD5037 inhibited voluntary alcohol intake upon systemic but not upon intracerebroventricular administration in doses that elicited anxiogenic-like behavior and blocked CB1R-induced hypothermia and catalepsy. The peripherally restricted hybrid CB1R antagonist/iNOS inhibitor
-MRI-1867 was also effective in reducing alcohol consumption after oral gavage, while its
enantiomer (CB1R inactive/iNOS inhibitor) was not. The two MRI-1867 enantiomers were equally effective in inhibiting an alcohol-induced increase in portal blood endotoxin concentration that was caused by increased gut permeability. We conclude that (i) activation of peripheral CB1R plays a dominant role in promoting alcohol intake and (ii) the iNOS inhibitory function of MRI-1867 helps in mitigating the alcohol-induced increase in endotoxemia.
Endocannabinoid (eCB), 2-arachidonoyl-glycerol (2-AG), the most abundant eCB in the brain, regulates diverse neural functions. Here we linked multiple homozygous loss-of-function mutations in 2-AG ...synthase diacylglycerol lipase β (DAGLB) to an early onset autosomal recessive Parkinsonism. DAGLB is the main 2-AG synthase in human and mouse substantia nigra (SN) dopaminergic neurons (DANs). In mice, the SN 2-AG levels were markedly correlated with motor performance during locomotor skill acquisition. Genetic knockdown of Daglb in nigral DANs substantially reduced SN 2-AG levels and impaired locomotor skill learning, particularly the across-session learning. Conversely, pharmacological inhibition of 2-AG degradation increased nigral 2-AG levels, DAN activity and dopamine release and rescued the locomotor skill learning deficits. Together, we demonstrate that DAGLB-deficiency contributes to the pathogenesis of Parkinsonism, reveal the importance of DAGLB-mediated 2-AG biosynthesis in nigral DANs in regulating neuronal activity and dopamine release, and suggest potential benefits of 2-AG augmentation in alleviating Parkinsonism.
In visceral obesity, an overactive endocannabinoid/CB1 receptor (CB1R) system promotes increased caloric intake and decreases energy expenditure, which are mitigated by global or peripheral CB1R ...blockade. In mice with diet-induced obesity (DIO), inhibition of food intake by the peripherally restricted CB1R antagonist JD5037 could be attributed to endogenous leptin due to the rapid reversal of hyperleptinemia that maintains leptin resistance, but the signaling pathway engaged by leptin has remained to be determined.
We analyzed the hypothalamic circuitry targeted by leptin following chronic treatment of DIO mice with JD5037.
Leptin treatment or an increase in endogenous leptin following fasting/refeeding induced STAT3 phosphorylation in neurons in the arcuate nucleus (ARC) in lean and JD5037-treated DIO mice, but not in vehicle-treated DIO animals. Co-localization of pSTAT3 in leptin-treated mice was significantly less common with NPY+ than with POMC+ ARC neurons. The hypophagic effect of JD5037 was absent in melanocortin-4 receptor (MC4R) deficient obese mice or DIO mice treated with a MC4R antagonist, but was maintained in NPY−/− mice kept on a high-fat diet.
Peripheral CB1R blockade in DIO restores sensitivity to endogenous leptin, which elicits hypophagia via the re-activation of melanocortin signaling in the ARC.
•High-fat diet-induced leptin resistance is reversed by peripheral CB1 blockade.•Restored leptin signaling by peripheral CB1 blockade occurs via POMC/MC4R pathway.•AgRP/NPY neurons are not required for peripheral CB1 blockade-induced hypophagia in mice with diet-induced obesity.
Synthetic cannabinoid (SC) use has persisted in the United States despite schedule-1 placement under the Synthetic Drug Abuse Prevention Act of 2012 1. Analysis of the National Poison Data System ...indicates that hospitalisations caused by SC use increased significantly between 2010 and 2015 2. Moreover, there is a trend of the increasing use of such compounds among adolescents 3. SCs are often 30–100-fold more potent than Δ
9
-tetrahydrocannabinol (THC), the major psychoactive ingredient of cannabis, in activating Cannabinoid receptor 1 (CB
1
R). Users are attracted to SCs because of the cheaper, novel and stronger highs such substances offer compared to cannabis, and because the compounds are not screened for in typical drug tests 1, 2. Among those hospitalised for SC use, some patients exhibited respiratory failure 4–7, pulmonary infiltrates 5, 7, alveolar damage or haemorrhage 5–7 and histopathologic features similar to organising pneumonia 4–6. The mechanism by which SCs damage pulmonary tissue has yet to be elucidated – whether by SC binding at CB
1
R, CB
2
R or another receptor, and what downstream effects such binding elicits. Solving this conundrum is the first step in optimising treatment for patients presenting with SC-related respiratory distress.
Synthetic cannabinoids (SCs) induce a pro-inflammatory condition by activating cannabinoid receptor 1 (CB
1
R) in the lungs of mice, which raises a potential therapeutic use of CB
1
R antagonists in SC-induced lung disease resulting in hospitalisation
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Heavy alcohol drinking has negative health effects in multiple organs. It predisposes lungs to inflammatory conditions associated with acute lung injury and increased incidence of pneumonia and ...sepsis, which may lead to death due to acute respiratory distress syndrome in some individuals with alcohol use disorder (AUD). In general, rodent models of alcohol exposure either do not recapitulate multiple organ injuries as seen in humans or require longer duration to establish tissue injury and inflammation. The recently introduced NIAAA model of alcohol-induced liver injury, characterized by a marked increase in steatosis and liver damage with 10 days of a liquid diet containing 5% ethanol followed by a single ethanol binge (5 g/kg). Therefore, we employed this model to explore the status of surfactant phospholipids, oxidative stress, tissue injury markers and inflammatory cytokines in lungs. In lungs of C57BL/6J mice, the alcohol feeding significantly increased levels of the surfactant phospholipid dipalmitoyl phosphatidylcholine (DPPC) as well as the truncated oxidized phosphatidylcholines palmitoyl oxovaleryl phosphatidyl-choline (POVPC), palmitoyl glutaryl phosphatidyl-choline (PGPC), palmitoyl oxo-nonanoyl phosphatidyl-choline (ALDO-PC), and palmitoyl azelaoyl phosphatidyl-choline (PAzePC) at 9 h post-binge. Additionally, gene expression of the enzymes catalyzing lipid oxidation, such as arachidonate 15-lipoxygenase (Alox15), prostaglandin synthase 2 (Ptgs2), Cytochrome P450 2E1 (Cyp2E1) and NADPH oxidase 1 (Nox1) were significantly increased. Furthermore, ethanol increased levels of the inflammatory cytokine Interleukin-17 in bronchoalveolar lavage fluid. In conclusion, the NIAAA alcohol feeding model might be suitable to study alcohol-induced lung injury and inflammation.
Chronic graft-versus-host disease (GVHD) can be associated with significant morbidity, in part because of nonreversible fibrosis, which impacts physical functioning (eye, skin, lung manifestations) ...and mortality (lung, gastrointestinal manifestations). Progress in preventing severe morbidity and mortality associated with chronic GVHD is limited by a complex and incompletely understood disease biology and a lack of prognostic biomarkers. Likewise, treatment advances for highly morbid manifestations remain hindered by the absence of effective organ-specific approaches targeting "irreversible" fibrotic sequelae and difficulties in conducting clinical trials in a heterogeneous disease with small patient numbers. The purpose of this document is to identify current gaps, to outline a roadmap of research goals for highly morbid forms of chronic GVHD including advanced skin sclerosis, fasciitis, lung, ocular and gastrointestinal involvement, and to propose strategies for effective trial design. The working group made the following recommendations: (1) Phenotype chronic GVHD clinically and biologically in future cohorts, to describe the incidence, prognostic factors, mechanisms of organ damage, and clinical evolution of highly morbid conditions including long-term effects in children; (2) Conduct longitudinal multicenter studies with common definitions and research sample collections; (3) Develop new approaches for early identification and treatment of highly morbid forms of chronic GVHD, especially biologically targeted treatments, with a special focus on fibrotic changes; and (4) Establish primary endpoints for clinical trials addressing each highly morbid manifestation in relationship to the time point of intervention (early versus late). Alternative endpoints, such as lack of progression and improvement in physical functioning or quality of life, may be suitable for clinical trials in patients with highly morbid manifestations. Finally, new approaches for objective response assessment and exploration of novel trial designs for small populations are required.
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