The therapeutic potential of targeting the peripheral endocannabinoid/CB1 receptor system.

European Journal of Internal Medicine

“Endocannabinoids (eCBs) are internal lipid mediators recognized by the cannabinoid-1 and -2 receptors (CB1R and CB2R, respectively), which also mediate the different physiological effects of marijuana. The endocannabinoid system, consisting of eCBs, their receptors, and the enzymes involved in their biosynthesis and degradation, is present in a vast number of peripheral organs. In this review we describe the role of the eCB/CB1R system in modulating the metabolism in several peripheral organs. We assess how eCBs, via activating the CB1R, contribute to obesity and regulate food intake. In addition, we describe their roles in modulating liver and kidney functions, as well as bone remodeling and mass. Special importance is given to emphasizing the efficacy of the recently developed peripherally restricted CB1R antagonists, which were pre-clinically tested in the management of energy homeostasis, and in ameliorating both obesity- and diabetes-induced metabolic complications.”

https://www.ncbi.nlm.nih.gov/pubmed/29336868

Peripheral modulation of the endocannabinoid system in metabolic disease.

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“Dysfunction of the endocannabinoid system (ECS) has been identified in metabolic disease.

Cannabinoid receptor 1 (CB1) is abundantly expressed in the brain but also expressed in the periphery. Cannabinoid receptor 2 (CB2) is more abundant in the periphery, including the immune cells.

In obesity, global antagonism of overexpressed CB1 reduces bodyweight but leads to centrally mediated adverse psychological outcomes.

Emerging research in isolated cultured cells or tissues has demonstrated that targeting the endocannabinoid system in the periphery alleviates the pathologies associated with metabolic disease.

Further, peripheral specific cannabinoid ligands can reverse aspects of the metabolic phenotype.

This Keynote review will focus on current research on the functionality of peripheral modulation of the ECS for the treatment of obesity.”

Cannabinoid Modulation of the Stressed Hippocampus.

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“Exposure to stressful situations is one of the risk factors for the precipitation of several psychiatric disorders, including Major Depressive Disorder, Posttraumatic Stress Disorder and Schizophrenia.

The hippocampal formation is a forebrain structure highly associated with emotional, learning and memory processes; being particularly vulnerable to stress. Exposure to stressful stimuli leads to neuroplastic changes and imbalance between inhibitory/excitatory networks. These changes have been associated with an impaired hippocampal function.

Endocannabinoids (eCB) are one of the main systems controlling both excitatory and inhibitory neurotransmission, as well as neuroplasticity within the hippocampus.

Cannabinoids receptors are highly expressed in the hippocampus, and several lines of evidence suggest that facilitation of cannabinoid signaling within this brain region prevents stress-induced behavioral changes.

Also, chronic stress modulates hippocampal CB1 receptors expression and endocannabinoid levels.

Moreover, cannabinoids participate in mechanisms related to synaptic plasticity and adult neurogenesis. Here, we discussed the main findings supporting the involvement of hippocampal cannabinoid neurotransmission in stress-induced behavioral and neuroplastic changes.”

https://www.ncbi.nlm.nih.gov/pubmed/29311804

https://www.frontiersin.org/articles/10.3389/fnmol.2017.00411/full

Prospects for the Use of Cannabinoid Receptor Ligands for the Treatment of Metabolic Syndrome and Atherosclerosis: Analysis of Experimental and Clinical Data.

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“An antagonist of central cannabinoid CB1 receptors rimonabant causes weight loss in patients with obesity and metabolic syndrome, improves blood lipid parameters, increases the adiponectin level, decreases the rate of glucose and glycosylated hemoglobin in patients with diabetes mellitus type-2. However, rimonabant adverse effects include depression, anxiety, nausea, and dizziness which are apparently due to the blockade of central CB1 receptors.

In mice with a high-calorie diet, we defined that the blockade of peripheral CB1 receptors prevents obesity, steatosis of the liver, improves lipid and carbohydrate metabolism. Experimental studies suggest that peripheral CB2 receptor agonists have antiatherogenic effect. To validate the expediency of clinical research of CB2 receptor agonists in patients with atherosclerosis the comparative analysis of antiatherogenic properties of cannabinoids should be performed. In addition, experiments are needed on the combination use of cannabinoids with well-known antiatherogenic agents, such as statins.”

Rimonabant Kills Colon Cancer Stem Cells without Inducing Toxicity in Normal Colon Organoids

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“Colorectal cancer (CRC), like other tumor types, is a highly heterogeneous disease. Within the tumor bulk, intra-tumoral heterogeneity is also ascribable to Cancer Stem Cells (CSCs) subpopulation, characterized by high chemoresistance and the unique ability to retain tumorigenic potential, thus associated to tumor recurrence. High dynamic plasticity of CSCs, makes the development of winning therapeutic strategies even more complex to completely eradicate tumor fuel.

Rimonabant, originally synthesized as antagonist/inverse agonist of Cannabinoid Receptor 1, is able to inactivate Wnt signaling, both in vitro and in vivo, in CRC models, through inhibition of p300-histone acetyltransferase activity. Since Wnt/β-Catenin pathway is the main player underlying CSCs dynamic, this finding candidates Rimonabant as potential modulator of cancer stemness, in CRC.

Overall, results from this work provided new insights on anti-tumor efficacy of Rimonabant, strongly suggesting that it could be a novel lead compound for CRC treatment.

 Anti-tumor action of cannabinoids in CRC was strongly supported by several authors.
The Endocannabinoid (EC) system role in the progression of CRC has been analyzed in vivo in the mouse model of azoxymethane-induced colon carcinogenesis, where cannabinoids-mediated reduction of precancerous lesions in the mouse colon was found.
In CRC cells, agonists and antagonists of both cannabinoid receptors, CB1 and CB2, showed anti-tumor action through induction of cell death with different mechanisms ranging from apoptosis to mitotic catastrophe”

Decisive role of P42/44 mitogen-activated protein kinase in Δ9-tetrahydrocannabinol-induced migration of human mesenchymal stem cells.

Related image “In past years, medical interest in Δ9-tetrahydrocannabinol (THC), the major psychoactive ingredient of the Cannabis plant, has been renewed due to the elucidation of the endocannabinoid system and diverse other receptor targets involved in biological cannabinoid effects.

The present study therefore investigates the impact of THC on the migration of mesenchymal stem cells (MSCs) which are known to be involved in various regenerative processes such as bone healing.

Collectively, this study demonstrates THC to exert a promigratory effect on MSCs via a CB1 receptor-dependent activation of p42/44 MAPK phosphorylation. This pathway may be involved in regenerative effects of THC and could be a target of pharmacological intervention.”   https://www.ncbi.nlm.nih.gov/pubmed/29285308

“Collectively and to the best of our knowledge, this is the first study reporting a promigratory impact of THC on MSCs, which may be an additional mechanism in the complex network of regenerative action of cannabinoids.”   http://www.oncotarget.com/index.php?journal=oncotarget&page=article&op=view&path[]=22517&path[]=71182

Role of the endogenous cannabinoid receptor 1 in brain injury induced by chronic intermittent hypoxia in rats.

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“This study investigated the effect of rimonabant, a cannabinoid receptor type 1 (CB1) antagonist, on calcium/calmodulin dependent protein kinase II (CaMKII) and CB1 in chronic intermittent hypoxia (CIH).

Rimonabant had a protective effect against CIH.” https://www.ncbi.nlm.nih.gov/pubmed/29264962

http://www.tandfonline.com/doi/abs/10.1080/00207454.2017.1420069

 

Cannabidiol restores intestinal barrier dysfunction and inhibits the apoptotic process induced by Clostridium difficile toxin A in Caco-2 cells.

 SAGE Journals

“Clostridium difficile toxin A is responsible for colonic damage observed in infected patients.

Drugs able to restore Clostridium difficile toxin A-induced toxicity have the potential to improve the recovery of infected patients. Cannabidiol is a non-psychotropic component of Cannabis sativa, which has been demonstrated to protect enterocytes against chemical and/or inflammatory damage and to restore intestinal mucosa integrity.

The purpose of this study was to evaluate (a) the anti-apoptotic effect and (b) the mechanisms by which cannabidiol protects mucosal integrity in Caco-2 cells exposed to Clostridium difficile toxin A.

RESULTS:

Clostridium difficile toxin A significantly decreased Caco-2 cells’ viability and reduced transepithelial electrical resistence values and RhoA guanosine triphosphate (GTP), bax, zonula occludens-1 and occludin protein expression, respectively. All these effects were significantly and concentration-dependently inhibited by cannabidiol, whose effects were completely abolished in the presence of the cannabinoid receptor type 1 (CB1) antagonist, AM251.

CONCLUSIONS:

Cannabidiol improved Clostridium difficile toxin A-induced damage in Caco-2 cells, by inhibiting the apoptotic process and restoring the intestinal barrier integrity, through the involvement of the CB1 receptor.”

https://www.ncbi.nlm.nih.gov/pubmed/29238589

“In the last decade, cannabinoids extracted from the marijuana plant (Cannabis sativa) and synthetic cannabinoids have shown numerous beneficial effects on gastrointestinal (GI) functions. Non-psychotropic phytocannabinoid cannabidiol (CBD) is one of the most interesting compounds, since it exerts a wide range of beneficial pharmacological actions on GI functions, ranging from antioxidant to antinflammatory activities. CBD has been shown to act as a non-competitive negative allosteric modulator of CB1 receptors. Notably, CBD is able to restore in vitro intestinal permeability increased by ethylenediaminetetraacetic acid (EDTA) or pro-inflammatory stimuli.

Clostridium difficile infection is the leading cause of hospital-acquired diarrhoea and pseudomembranous colitis. Clostridium difficile-Toxin A significantly affects enterocytes permeability leading to apoptosis and colonic mucosal damage.

In the present study, we showed that Cannabidiol, a non-psychotropic component of Cannabis sativa significantly inhibit the apoptosis rate in TcdA-exposed cells and restores barrier function by a significant RhoA GTP rescue.

We also provide evidence that the effects of Cannabidiol are mediated by CB-1 receptor.

Given the absence of any significant toxic effect in humans, cannabidiol may ideally represent an effective adjuvant treatment for Clostridium difficile-associated colitis.”   http://journals.sagepub.com/doi/10.1177/2050640617698622

Novel Peripherally Restricted Cannabinoid 1 Receptor Selective Antagonist TXX-522 with Prominent Weight-Loss Efficacy in Diet Induced Obese Mice.

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“The clinical development of the first generation of globally active cannabinoid 1 receptor (CB1R) antagonists was suspended because of their adverse neuropsychiatric effects. Selective blockade of peripheral CB1Rs has the potential to provide a viable strategy for the treatment of severe obesity while avoiding these central nervous system side effects.

In the current study, a novel compound (TXX-522) was rationally designed based on the parent nucleus of a classical CB1R-selective antagonist/inverse agonist, rimonabant (SR141716A).

TXX-522 showed good binding, CB1R-selectivity (over the CB2R), and functional antagonist activities in a range of in vitro molecular and cellular assays.

In vivo analysis of the steady state distribution of TXX-522 in the rat brain and blood tissues and the assay of its functional effects on CB1R activity collectively showed that TXX-522 showed minimal brain penetration. Moreover, the in vivo pharmacodynamic study further revealed that TXX-522 had good oral bioavailability and a potent anti-obesity effect, and ameliorated insulin resistance in high-fat diet-induced obese mice. No impact on food intake was observed in this model, confirming the limited brain penetration of this compound.

Thus, the current study indicates that TXX-522 is a novel and potent peripherally acting selective CB1R antagonist with the potential to control obesity and related metabolic disorders.”

https://www.ncbi.nlm.nih.gov/pubmed/29051736

https://www.frontiersin.org/articles/10.3389/fphar.2017.00707/full

LH-21 and Abn-CBD improve β-cell function in isolated human and mouse islets through GPR55-dependent and -independent signalling.

Diabetes, Obesity and Metabolism

“CB1 and GPR55 are GPCRs expressed by islet β-cells. Pharmacological compounds have been used to investigate their function, but off-target effects of ligands have been reported.

This study examined the effects of Abn-CBD (GPR55 agonist) and LH-21 (CB1 antagonist) on human and mouse islet function, and islets from GPR55-/- mice were used to determine signalling via GPR55.

RESULTS:

Abn-CBD potentiated glucose-stimulated insulin secretion and elevated [Ca2+ ]i in human islets and islets from both GPR55+/+ and GPR55-/- mice. LH-21 also increased insulin secretion and [Ca2+ ]i in human islets and GPR55+/+ mouse islets, but concentrations of LH-21 up to 0.1 μM were ineffective in islets from GPR55-/- mice. Neither ligand affected basal insulin secretion or islet cAMP levels. Abn-CBD and LH-21 reduced cytokine-induced apoptosis in human islets and GPR55+/+ mouse islets, and these effects were suppressed following GPR55 deletion. They also increased β-cell proliferation: the effects of Abn-CBD were preserved in islets from GPR55-/- mice, while those of LH-21 were abolished. Abn-CBD and LH-21 increased AKT phosphorylation in mouse and human islets.

CONCLUSIONS:

This study demonstrated that Abn-CBD and LH-21 improve human and mouse islet β-cell function and viability. Use of islets from GPR55-/- mice suggests that designation of Abn-CBD and LH-21 as GPR55 agonist and CB1 antagonist, should be revised.”

https://www.ncbi.nlm.nih.gov/pubmed/29205751

http://onlinelibrary.wiley.com/doi/10.1111/dom.13180/abstract