Tag Archives: endocannabinoids

Review: The Role of Cannabinoids on Esophageal Function-What We Know Thus Far.

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Mary Ann Liebert, Inc. publishers

“The endocannabinoid system (ECS) primarily consists of cannabinoid receptors (CBRs), endogenous ligands, and enzymes for endocannabinoid biosynthesis and inactivation. Although the presence of CBRs, both CB1 and CB2, as well as a third receptor (G-protein receptor 55 [GPR55]), has been established in the gastrointestinal (GI) tract, few studies have focused on the role of cannabinoids on esophageal function. To date, studies have shown their effect on GI motility, inflammation and immunity, intestinal and gastric acid secretion, nociception and emesis pathways, and appetite control. Given the varying and sometimes limited efficacy of current medical therapies for diseases of the esophagus, further understanding and investigation into the interplay of the ECS on esophageal health and disease may present new therapeutic modalities that may help advance current treatment options. In this brief review, the current understanding of the ECS role in various esophageal functions and disorders is presented.”

https://www.ncbi.nlm.nih.gov/pubmed/29098187

http://online.liebertpub.com/doi/10.1089/can.2017.0031

N-Arachidonoyl Dopamine: A Novel Endocannabinoid and Endovanilloid with Widespread Physiological and Pharmacological Activities.

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Mary Ann Liebert, Inc. publishers

“N-arachidonoyl dopamine (NADA) is a member of the family of endocannabinoids to which several other N-acyldopamines belong as well. Their activity is mediated through various targets that include cannabinoid receptors or transient receptor potential vanilloid (TRPV)1. Synthesis and degradation of NADA are not yet fully understood. Nonetheless, there is evidence that NADA plays an important role in nociception and inflammation in the central and peripheral nervous system. The TRPV1 receptor, for which NADA is a potent agonist, was shown to be an endogenous transducer of noxious heat. Moreover, it has been demonstrated that NADA exerts protective and antioxidative properties in microglial cell cultures, cortical neurons, and organotypical hippocampal slice cultures. NADA is present in very low concentrations in the brain and is seemingly not involved in activation of the classical pathways. We believe that treatment with exogenous NADA during and after injury might be beneficial. This review summarizes the recent findings on biochemical properties of NADA and other N-acyldopamines and their role in physiological and pathological processes. These findings provide strong evidence that NADA is an effective agent to manage neuroinflammatory diseases or pain and can be useful in designing novel therapeutic strategies.”

https://www.ncbi.nlm.nih.gov/pubmed/29082315

http://online.liebertpub.com/doi/10.1089/can.2017.0015

An Update on Non-CB1, Non-CB2 Cannabinoid Related G-Protein-Coupled Receptors

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Mary Ann Liebert, Inc. publishers

“The endocannabinoid system (ECS) has been shown to be of great importance in the regulation of numerous physiological and pathological processes. To date, two Class A G-protein-coupled receptors (GPCRs) have been discovered and validated as the main therapeutic targets of this system: the cannabinoid receptor type 1 (CB1), which is the most abundant neuromodulatory receptor in the brain, and the cannabinoid receptor type 2 (CB2), predominantly found in the immune system among other organs and tissues. Endogenous cannabinoid receptor ligands (endocannabinoids) and the enzymes involved in their synthesis, cell uptake, and degradation have also been identified as part of the ECS. However, its complex pharmacology suggests that other GPCRs may also play physiologically relevant roles in this therapeutically promising system. In the last years, GPCRs such as GPR18 and GPR55 have emerged as possible missing members of the cannabinoid family. This categorization still stimulates strong debate due to the lack of pharmacological tools to validate it. Because of their close phylogenetic relationship, the Class A orphan GPCRs, GPR3, GPR6, and GPR12, have also been associated with the cannabinoids. Moreover, certain endo-, phyto-, and synthetic cannabinoid ligands have displayed activity at other well-established GPCRs, including the opioid, adenosine, serotonin, and dopamine receptor families. In addition, the cannabinoid receptors have also been shown to form dimers with other GPCRs triggering cross-talk signaling under specific conditions. In this mini review, we aim to provide insight into the non-CB1, non-CB2 cannabinoid-related GPCRs that have been reported thus far. We consider the physiological relevance of these molecular targets in modulating the ECS.”

http://online.liebertpub.com/doi/abs/10.1089/can.2017.0036

Pharmacological augmentation of endocannabinoid signaling reduces the neuroendocrine response to stress.

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Psychoneuroendocrinology

“Activation of the hypothalamic-pituitary-adrenal axis (HPA) is critical for survival when the organism is exposed to a stressful stimulus. The endocannabinoid system (ECS) is currently considered an important neuromodulator involved in numerous pathophysiological processes and whose primary function is to maintain homeostasis. In the tissues constituting the HPA axis, all the components of the ECS are present and the activation of this system acts in parallel with changes in the activity of numerous neurotransmitters, including nitric oxide (NO). NO is widely distributed in the brain and adrenal glands and recent studies have shown that free radicals, and in particular NO, may play a crucial role in the regulation of stress response. Our objective was to determine the participation of the endocannabinoid and NOergic systems as probable mediators of the neuroendocrine HPA axis response to a psychophysical acute stress model in the adult male rat. Animals were pre-treated with cannabinoid receptors agonists and antagonists at central and systemic level prior to acute restraint exposure. We also performed in vitro studies incubating adrenal glands in the presence of ACTH and pharmacological compounds that modifies ECS components. Our results showed that the increase in corticosterone observed after acute restraint stress is blocked by anandamide administered at both central and peripheral level. At hypothalamic level both cannabinoid receptors (CB1 and CB2) are involved, while in the adrenal gland, anandamide has a very potent effect in suppressing ACTH-induced corticosterone release that is mainly mediated by vanilloid TRPV1 receptors. We also observed that stress significantly increased hypothalamic mRNA levels of CB1 as well as adrenal mRNA levels of TRPV1 receptor. In addition, anandamide reduced the activity of the nitric oxide synthase enzyme during stress, indicating that the anti-stress action of endocannabinoids may involve a reduction in NO production at hypothalamic and adrenal levels. In conclusion, an endogenous cannabinoid tone maintains the HPA axis in a stable basal state, which is lost with a noxious stimulus. In this case, the ECS dampens the response to stress allowing the recovery of homeostasis. Moreover, our work further contributes to in vitro evidence for a participation of the endocannabinoid system by inhibiting corticosterone release directly at the adrenal gland level.”

https://www.ncbi.nlm.nih.gov/pubmed/29065362

http://www.psyneuen-journal.com/article/S0306-4530(17)30614-5/fulltext

[Cannabinoid receptor system regulates ion channels and synaptic transmission in retinal cells].

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Image result for Sheng Li Xue Bao. journal

“Endocannabinoid receptor system is extensively expressed in the vertebrate retina. There are two types of cannabinoid receptors, CB1 and CB2. Activation of these two receptors by endocannabinoids N-arachidonoylethanolamide (anandamine, AEA) and 2-arachidonyl glycerol (2-AG) regulates multiple neuronal and glial ion channels, thus getting involved in retinal visual information processing. In this review, incorporating our results, we discuss the modulation of cannabinoid CB1 and CB2 receptors on retinal neuronal and glial ion channels and retinal synaptic transmission.”

https://www.ncbi.nlm.nih.gov/pubmed/29063116

Monoacylglycerol lipase inhibitor JZL184 prevents HIV-1 gp120-induced synapse loss by altering endocannabinoid signaling.

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Neuropharmacology

“Monoacylglycerol lipase (MGL) hydrolyzes 2-arachidonoylglycerol to arachidonic acid and glycerol. Inhibition of MGL may attenuate neuroinflammation by enhancing endocannabinoid signaling and decreasing prostaglandin (PG) production. Almost half of HIV infected individuals are afflicted with HIV-associated neurocognitive disorder (HAND), a neuroinflammatory disease in which cognitive decline correlates with synapse loss. HIV infected cells shed the envelope protein gp120 which is a potent neurotoxin that induces synapse loss. Here, we tested whether inhibition of MGL, using the selective inhibitor JZL184, would prevent synapse loss induced by gp120. The number of synapses between rat hippocampal neurons in culture was quantified by imaging clusters of a GFP-tagged antibody-like protein that selectively binds to the postsynaptic scaffolding protein, PSD95. JZL184 completely blocked gp120-induced synapse loss. Inhibition of MGL decreased gp120-induced interleukin-1β (IL-1β) production and subsequent potentiation of NMDA receptor-mediated calcium influx. JZL184-mediated protection of synapses was reversed by a selective cannabinoid type 2 receptor (CB2R) inverse agonist/antagonist. JZL184 also reduced gp120-induced prostaglandin E2 (PGE2) production; PG signaling was required for gp120-induced IL-1β expression and synapse loss. Inhibition of MGL prevented gp120-induced synapse loss by activating CB2R resulting in decreased production of the inflammatory cytokine IL-1β. Because PG signaling was required for gp120-induced synapse loss, JZL184-induced decreases in PGE2 levels may also protect synapses. MGL presents a promising target for preventing synapse loss in neuroinflammatory conditions such as HAND.”

https://www.ncbi.nlm.nih.gov/pubmed/29061509

http://www.sciencedirect.com/science/article/pii/S0028390817304902?via%3Dihub

Control of myogenic tone and agonist induced contraction of intramural coronary resistance arterioles by cannabinoid type 1 receptors and endocannabinoids.

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“It was tested whether intrinsic CB1R activation modifies myogenic and agonist induced contraction of intramural coronary resistance arteries of the rat. CB1R protein was detected by immuno-histochemistry and by Western blot, its mRNA by qRT-PCR in their wall. Microsurgically prepared cylindrical coronary segments (∼100-150μm) developed myogenic contraction (∼20% of relaxed luminal diameter), from which a substantial relaxation (∼15%) in response to WIN55212 (a specific agonist of the CB1Rs) has been found. CB1R-mediated relaxation was blocked by O2050 and AM251 (neutral antagonist and inverse agonist of the CB1R, respectively) and was partially blocked by the NO synthase blocker LNA. CB1R blockade enhanced myogenic tone and augmented AngII-induced vasoconstriction (from 17,8±1,2 to 29,1±2,9%, p <0,05). Inhibition of diacylglycerol lipase by tetrahydrolipstatin, (inhibitor of endogenous 2-AG production) also augmented coronary vasoconstriction. These observations prove that vascular endocannabinoids are significant negative modulators of the myogenic and agonist-induced tone of intramural coronary arterioles acting through CB1Rs.”

https://www.ncbi.nlm.nih.gov/pubmed/29031792

http://www.sciencedirect.com/science/article/pii/S1098882317300047

Human bone marrow mesenchymal stem cells secrete endocannabinoids that stimulate in vitro hematopoietic stem cell migration effectively comparable to beta adrenergic stimulation.

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Experimental Hematology Home

“Granulocyte Colony-Stimulating Factor (G-CSF) is a well-known hematopoietic stem cell (HSC) mobilizing agent used in both allogeneic and autologous transplantation. However, a proportion of patients or healthy donors fail to mobilize sufficient number of cells. New mobilization agents are therefore needed.

Endocannabinoids (eCBs) are endogenous lipid mediators generated in the brain and peripheral tissues and activate the cannabinoid receptors (CB1, CB2). We suggest that eCBs may act as mobilizers of hematopoietic stem cells (HSC) from the BM under stress conditions as beta adrenergic receptors (Adrβ).

This study demonstrates that bone marrow (BM) mesenchymal stem cells (MSCs) secrete anandamide (AEA) and 2-arachidonylglycerol (2-AG), and peripheral blood (PB) and BM microenvironment contain AEA and 2-AG. 2-AG levels are significantly higher in PB of the G-CSF treated group when compared to BM plasma. BM mononuclear cells (MNCs) and CD34+HSCs, express CB1, CB2 and Adrβ subtypes. CD34+HSCs had higher CB1 and CB2 receptor expression in G-CSF untreated and treated groups when compared to MSCs. MNCs but not MSCs expressed CB1 and CB2 receptors based on qRT-PCR and flow cytometry (FC). AEA and 2-AG stimulated HSC migration was blocked by eCB receptor antagonists in in vitro migration assay.

In conclusion, components of the eCB system and their interaction with Adrβ subtypes were demonstrated on HSCs and MSCs of G-CSF treated and untreated healthy donors in vitro, revealing that eCBs might be potential candidates to enhance or facilitate G-CSF-mediated HSC migration under stress conditions in a clinical setting.”

https://www.ncbi.nlm.nih.gov/pubmed/29030083

http://www.exphem.org/article/S0301-472X(17)30813-5/fulltext

Cannabinoid CB1 receptor overactivity contributes to the pathogenesis of idiopathic pulmonary fibrosis.

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“Idiopathic pulmonary fibrosis (IPF) is a life-threatening disease without effective treatment, highlighting the need for identifying new targets and treatment modalities. The pathogenesis of IPF is complex, and engaging multiple targets simultaneously might improve therapeutic efficacy.

To assess the role of the endocannabinoid/cannabinoid receptor 1 (endocannabinoid/CB1R) system in IPF and its interaction with inducible nitric oxide synthase (iNOS) as dual therapeutic targets, we analyzed lung fibrosis and the status of the endocannabinoid/CB1R system and iNOS in mice with bleomycin-induced pulmonary fibrosis (PF) and in lung tissue and bronchoalveolar lavage fluid (BALF) from patients with IPF, as well as controls. In addition, we investigated the antifibrotic efficacy in the mouse PF model of an orally bioavailable and peripherally restricted CB1R/iNOS hybrid inhibitor.

We report that increased activity of the endocannabinoid/CB1R system parallels disease progression in the lungs of patients with idiopathic PF and in mice with bleomycin-induced PF and is associated with increased tissue levels of interferon regulatory factor-5. Furthermore, we demonstrate that simultaneous engagement of the secondary target iNOS by the hybrid CB1R/iNOS inhibitor has greater antifibrotic efficacy than inhibition of CB1R alone. This hybrid antagonist also arrests the progression of established fibrosis in mice, thus making it a viable candidate for future translational studies in IPF.”  https://www.ncbi.nlm.nih.gov/pubmed/28422760

 “The limited success of medications with a single target suggests that multitargeted therapies may be more effective, considering the multifactorial pathology of IPF. Here, we report that a dual-target hybrid inhibitor of peripheral CB1R and iNOS completely arrested the progression of BL-PF and dramatically improved the survival rate in a progression arrest treatment paradigm, providing proof of principle for a polypharmacology approach in this preclinical model of IPF. “
 https://insight.jci.org/articles/view/92281

“Our results show that CB1 signaling plays a key pathological role in the development of radiation-induced pulmonary inflammation and fibrosis, and peripherally restricted CB1 antagonists may represent a novel therapeutic approach against this devastating complication of radiotherapy/irradiation. In summary, we provide the first evidence on the key pathological role of CB1 signaling in radiation-induced pulmonary fibrogenesis and show that peripherally restricted CB1 antagonists may represent a novel therapeutic approach against this devastating and untreatable complication of radiotherapy/irradiation. Our results also suggest that targeting CB1 may provide benefits in other lung diseases associated with inflammation and fibrosis.”  http://www.atsjournals.org/doi/10.1165/rcmb.2014-0331OC

“Pure Δ9-tetrahydrocannabivarin and a Cannabis sativa extract with high content in Δ9-tetrahydrocannabivarin inhibit nitrite production in murine peritoneal macrophages. THCV down-regulated the over-expression of inducible nitric oxide synthase (iNOS). THCV counteracted LPS-induced up-regulation of CB1 receptors.  Cannabis use has immunomodulatory and anti-inflammatory effects.”  http://www.ncbi.nlm.nih.gov/pubmed/27498155

 “As a class, the cannabinoids are generally free from the adverse effects associated with NSAIDs. Their clinical development thus provides a new approach to treatment of diseases characterized by acute and chronic inflammation and fibrosis. The review concludes with a presentation of a possible mechanism for the anti-inflammatory and antifibrotic actions of these substances. Thus, several cannabinoids may be considered candidates for development as anti-inflammatory and antifibrotic agents.”  https://www.ncbi.nlm.nih.gov/pubmed/27435265

Endocannabinoid-related compounds in gastrointestinal diseases.

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Journal of Cellular and Molecular Medicine

“The endocannabinoid system (ECS) is an endogenous signalling pathway involved in the control of several gastrointestinal (GI) functions at both peripheral and central levels. In recent years, it has become apparent that the ECS is pivotal in the regulation of GI motility, secretion and sensitivity, but endocannabinoids (ECs) are also involved in the regulation of intestinal inflammation and mucosal barrier permeability, suggesting their role in the pathophysiology of both functional and organic GI disorders. Genetic studies in patients with irritable bowel syndrome (IBS) or inflammatory bowel disease have indeed shown significant associations with polymorphisms or mutation in genes encoding for cannabinoid receptor or enzyme responsible for their catabolism, respectively. Furthermore, ongoing clinical trials are testing EC agonists/antagonists in the achievement of symptomatic relief from a number of GI symptoms. Despite this evidence, there is a lack of supportive RCTs and relevant data in human beings, and hence, the possible therapeutic application of these compounds is raising ethical, political and economic concerns. More recently, the identification of several EC-like compounds able to modulate ECS function without the typical central side effects of cannabino-mimetics has paved the way for emerging peripherally acting drugs. This review summarizes the possible mechanisms linking the ECS to GI disorders and describes the most recent advances in the manipulation of the ECS in the treatment of GI diseases.”

https://www.ncbi.nlm.nih.gov/pubmed/28990365

http://onlinelibrary.wiley.com/doi/10.1111/jcmm.13359/abstract