Category Archives: Endocannabinoid System

Advances towards the Discovery of GPR55 Ligands.

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“The G-protein-coupled receptor 55 (GPR55) was identified in 1999.

It was proposed as a novel member of the endocannabinoid system due to the fact that some endogenous, plant-derived and synthetic cannabinoid ligands act on GPR55. However, the complexity of the cellular downstream signaling pathways related to GPR55 activation delayed the discovery of selective GPR55 ligands.

It was only a few years ago that the high throughput screening of libraries of pharmaceutical companies and governmental organizations allowed to identify selective GPR55 agonists and antagonists. Since then, several GPR55 modulator scaffolds have been reported.

The relevance of GPR55 has been explored in diverse physiological and pathological processes revealing its role in inflammation, neuropathic pain, bone physiology, diabetes and cancer.

Considering GPR55 as a new promising therapeutic target, there is a clear need for new selective and potent GPR55 modulators. This review will address a current structural update of GPR55 ligands.”

http://www.ncbi.nlm.nih.gov/pubmed/27109575

Endocannabinoids signaling: Molecular mechanisms of liver regulation and diseases.

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“The endocannabinoid system (ECS) includes endocannabinoids (eCBs), cannabinoid (CB) receptors and the enzymes that are responsible for endocannabinoid production and metabolism. The ECS has been reported to be present in both brain and peripheral tissues.

Recent studies have indicated that eCBs and their receptors are involved in the development of various liver diseases. They were found to be altered in response to many danger factors.

It is generally accepted that eCB may exert a protective action via CB2 receptors in different liver diseases. However, eCBs have also been demonstrated to have pathogenic role via their CB1 receptors.

Although the therapeutic potential of CB1 receptor blockade in liver diseases is limited by its neuropsychiatric side effects, many studies have been conducted to search for novel, peripherally restricted CB1 antagonists or CB2 agonists, which may minimize their neuropsychiatric side effects in clinical use.

This review summarizes the current understanding of the ECS in liver diseases and provides evidence for the potential to develop new therapeutic strategies for the treatment of these liver diseases.”

http://www.ncbi.nlm.nih.gov/pubmed/27100518

Anandamide and its metabolites: what are their roles in the kidney?

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 “Anandamide (AEA) is the N-acyl ethanolamide of arachidonic acid, an agonist of cannabinoid and non-cannabinoid receptors in the body. The kidneys are enriched in AEA and in enzymes that metabolize AEA, but the roles of AEA and its metabolites in the kidney remain poorly understood.

This system likely is involved in the regulation of renal blood flow and hemodynamics and of tubular sodium and fluid reabsorption. It may act as a neuromodulator of the renal sympathetic nervous system. AEA and its cyclooxygenase-2 metabolites, the prostamides, in the renal medulla may represent a unique antihypertensive system involved in the long-term control of blood pressure. AEA and its metabolites are also implicated as modulators of inflammation and mediators of signaling in inflammation.

AEA and its metabolites may be influential in chronic kidney disease states associated with inflammation and cardiovascular diseases associated with hyperhomocysteinemia. The current knowledge of the roles of AEA and its derivatives highlights the need for further research to define and potentially exploit the role of this endocannabinoid system in the kidney.”

http://www.ncbi.nlm.nih.gov/pubmed/27100705

ENDOCANNABINOID SYSTEM: A multi-facet therapeutic target.

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“Cannabis sativa is also popularly known as marijuana. It is being cultivated and used by man for recreational and medicinal purposes from many centuries.

Study of cannabinoids was at bay for very long time and its therapeutic value could not be adequately harnessed due to its legal status as proscribed drug in most of the countries.

The research of drugs acting on endocannabinoid system has seen many ups and down in recent past. Presently, it is known that endocannabinoids has role in pathology of many disorders and they also serve “protective role” in many medical conditions.

Several diseases like emesis, pain, inflammation, multiple sclerosis, anorexia, epilepsy, glaucoma, schizophrenia, cardiovascular disorders, cancer, obesity, metabolic syndrome related diseases, Parkinson’s disease, Huntington’s disease, Alzheimer’s disease and Tourette’s syndrome could possibly be treated by drugs modulating endocannabinoid system.

Presently, cannabinoid receptor agonists like nabilone and dronabinol are used for reducing the chemotherapy induced vomiting. Sativex (cannabidiol and THC combination) is approved in the UK, Spain and New Zealand to treat spasticity due to multiple sclerosis. In US it is under investigation for cancer pain, another drug Epidiolex (cannabidiol) is also under investigation in US for childhood seizures. Rimonabant, CB1 receptor antagonist appeared as a promising anti-obesity drug during clinical trials but it also exhibited remarkable psychiatric side effect profile. Due to which the US Food and Drug Administration did not approve Rimonabant in US. It sale was also suspended across the EU in 2008.

Recent discontinuation of clinical trial related to FAAH inhibitor due to occurrence of serious adverse events in the participating subjects could be discouraging for the research fraternity. Despite of some mishaps in clinical trials related to drugs acting on endocannabinoid system, still lot of research is being carried out to explore and establish the therapeutic targets for both cannabinoid receptor agonists and antagonists.

One challenge is to develop drugs that target only cannabinoid receptors in a particular tissue and another is to invent drugs that acts selectively on cannabinoid receptors located outside the blood brain barrier. Besides this, development of the suitable dosage forms with maximum efficacy and minimum adverse effects is also warranted.

Another angle to be introspected for therapeutic abilities of this group of drugs is non-CB1 and non-CB2 receptor targets for cannabinoids.

In order to successfully exploit the therapeutic potential of endocannabinoid system, it is imperative to further characterize the endocannabinoid system in terms of identification of the exact cellular location of cannabinoid receptors and their role as “protective” and “disease inducing substance”, time-dependent changes in the expression of cannabinoid receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/27086601

Toll-like receptor signalling as a cannabinoid target in Multiple Sclerosis.

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“Toll-like receptors (TLRs) are the sensors of pathogen-associated molecules that trigger tailored innate immune intracellular signalling responses to initiate innate immune reactions.

Data from the experimental autoimmune encephalomyelitis (EAE) model indicates that TLR signalling machinery is a pivotal player in the development of murine EAE. To compound this, data from human studies indicate that complex interplay exists between TLR signalling and Multiple Sclerosis (MS) pathogenesis.

Cannabis-based therapies are in clinical development for the management of a variety of medical conditions, including MS. In particular Sativex®, a combination of plant-derived cannabinoids, is an oromucosal spray with efficacy in MS patients, particularly those with neuropathic pain and spasticity.

Despite this, the precise cellular and molecular mechanisms of action of Sativex® in MS patients remains unclear. This review will highlight evidence that novel interplay exists between the TLR and cannabinoid systems, both centrally and peripherally, with relevance to the pathogenesis of MS.”

http://www.ncbi.nlm.nih.gov/pubmed/27079840

Synthesis and pharmacological evaluation of new biphenylic derivatives as CB2 receptor ligands.

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“Targeting type-2 cannabinoid receptor (CB2) is considered a feasible strategy to develop new drugs for the treatment of diseases like neuropathic pain, chronic inflammation, neurodegenerative disorders and cancer.

Such drugs are devoid of the undesired central side effects that are typically mediated by the CB1 receptor.

In this work we synthesized 18 biphenylic carboxamides as new CB2-selective ligands and evaluated their pharmacological profiles. The functional activity of these compounds is strongly influenced by the nature of the substituent at position 4′ and 5 of the biphenyl scaffold.

Position 5 seems to be responsible for the agonist or inverse agonist behaviour independently of the substituent in position 4′, with the exception of the methoxyl group which transforms both full agonists and inverse agonists into neutral antagonists.

This study provides a novel complete toolbox of CB2 functional modulators that derive from the same chemical scaffold. Such probes may be useful to investigate the biological role of CB2 receptors in cellular assays.”

http://www.ncbi.nlm.nih.gov/pubmed/27078864

Production of endocannabinoids by activated T cells and B cells modulates inflammation associated with delayed type hypersensitivity.

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“Endocannabinoids are endogenous ligands for the cannabinoid (CB) receptors which include anandamide (AEA) and (2-AG). 2-AG has been linked to inflammation due to its elevated expression in animal models of autoimmunity and hypersensitivity.

However, administration of exogenous 2-AG has been shown to suppress inflammation making its precise role unclear. In the current study, we investigated the role of 2-AG following immunization of C57BL/6 (BL6) mice with methylated BSA (mBSA) antigen, which triggers both delayed type hypersensitivity (DTH) and antibody response.

Together, these data show for the first time that activated T and B cells produce 2-AG, which plays a negative regulatory role to decrease DTH via inhibition of T-cell activation and proliferation.

Moreover, these findings suggest that exogenous 2-AG treatment can be used therapeutically in Th1- or Th17-driven disease.”  http://www.ncbi.nlm.nih.gov/pubmed/27064137

“∆9-Tetrahydrocannabinol (THC) is one of the major bioactive cannabinoids derived from the Cannabis sativa plant and is known for its anti-inflammatory properties. Delayed-type hypersensitivity (DTH) is driven by proinflammatory T helper cells including the classic inflammatory Th1 lineage as well as the more recently discovered Th17 lineage. In the current study, we investigated whether THC can alter the induction of Th1/Th17 cells involved in mBSA-induced DTH response… In summary, the current study suggests that THC treatment during DTH response can simultaneously inhibit Th1/Th17 activation via regulation of microRNA (miRNA) expression.• THC treatment inhibits simultaneous Th1/Th17 driven inflammation. • THC treatment corrects DTH-mediated microRNA dysregulation. • THC treatment regulates proinflammatory cytokines and transcription factors.” http://www.ncbi.nlm.nih.gov/pubmed/27038180

http://www.thctotalhealthcare.com/tag/anti-inflammatory/

Antitumorigenic targets of cannabinoids – current status and implications.

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“Molecular structures of the endocannabinoid system have gained interest as potential pharmacotherapeutical targets for systemic cancer treatment.

The present review covers the contribution of the endocannabinoid system to cancer progression. Particular focus will be set on the accumulating preclinical data concerning antimetastatic, anti-invasive and anti-angiogenic mechanisms induced by cannabinoids.

Expert opinion: The main goal of targeting endocannabinoid structures for systemic anticancer treatment is the comparatively good safety profile of cannabinoid compounds.

In addition, antitumorigenic mechanisms of cannabinoids are not restricted to a single molecular cascade but involve multiple effects on various levels of cancer progression such as angiogenesis and metastasis. Particularly the latter effect has gained interest for pharmacological interventions.

Thus, drugs aiming at the endocannabinoid system may represent potential “antimetastatics” for an upgrade of a future armamentarium against cancer diseases.”

http://www.ncbi.nlm.nih.gov/pubmed/27070944

http://www.thctotalhealthcare.com/category/cancer/

Immunohistochemical analysis of cannabinoid receptor 1 expression in steatotic rat livers.

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“The primary aim of the present study was to determine the expression levels of cannabinoid receptor type 1 (CB1) in steatotic rat livers.  The secondary aim was to clarify whether steatosis and inflammation are more marked in areas with increased CB1 overexpression.

The expression of CB1 and the number of cells overexpressing CB1 were determined. Steatosis was scored according to the Dixon scoring system.

CB1 overexpression and steatosis were detected in hepatocytes from all 38 livers sampled. The expression of CB1 was more marked in hepatocytes localized next to portal triads. Near the central veins, the expression was significantly weaker. Steatosis was more marked in areas of increased CB1 overexpression. Lymphocyte infiltration was more commonly observed in areas of increased CB1 overexpression.

Therefore, the present results indicate that CB1 receptors are overexpressed in areas with steatosis, and indicate that CB1 in hepatocytes contributes to the formation of steatosis in rats, even prior to its progression to steatohepatitis.

These results are consistent with publications reporting that CB1 in hepatocytes increases lipogenesis and contributes to inflammation.”

http://www.ncbi.nlm.nih.gov/pubmed/27073427

http://www.thctotalhealthcare.com/category/liver-disease/

Orexin-A represses satiety-inducing POMC neurons and contributes to obesity via stimulation of endocannabinoid signaling.

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“In the hypothalamic arcuate nucleus (ARC), proopiomelanocortin (POMC) neurons and the POMC-derived peptide α-melanocyte-stimulating hormone (α-MSH) promote satiety. POMC neurons receive orexin-A (OX-A)-expressing inputs and express both OX-A receptor type 1 (OX-1R) and cannabinoid receptor type 1 (CB1R) on the plasma membrane.

OX-A is crucial for the control of wakefulness and energy homeostasis and promotes, in OX-1R-expressing cells, the biosynthesis of the endogenous counterpart of marijuana’s psychotropic and appetite-inducing component Δ9-tetrahydrocannabinol, i.e., the endocannabinoid 2-arachidonoylglycerol (2-AG), which acts at CB1R.

We report that OX-A/OX-1R signaling at POMC neurons promotes 2-AG biosynthesis, hyperphagia, and weight gain by blunting α-MSH production via CB1R-induced and extracellular-signal-regulated kinase 1/2 activation- and STAT3 inhibition-mediated suppression ofPomcgene transcription. Because the systemic pharmacological blockade of OX-1R by SB334867 caused anorectic effects by reducing food intake and body weight, our results unravel a previously unsuspected role for OX-A in endocannabinoid-mediated promotion of appetite by combining OX-induced alertness with food seeking. Notably, increased OX-A trafficking was found in the fibers projecting to the ARC of obese mice (ob/oband high-fat diet fed) concurrently with elevation of OX-A release in the cerebrospinal fluid and blood of mice.

Furthermore, a negative correlation between OX-A and α-MSH serum levels was found in obese mice as well as in human obese subjects (body mass index > 40), in combination with elevation of alanine aminotransferase and γ-glutamyl transferase, two markers of fatty liver disease.

These alterations were counteracted by antagonism of OX-1R, thus providing the basis for a therapeutic treatment of these diseases.”

http://www.ncbi.nlm.nih.gov/pubmed/27071101