Category Archives: Endocannabinoid System

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

Cannabinoid Receptors CB1 and CB2 Modulate the Electroretinographic Waves in Vervet Monkeys.

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“The expression patterns of the cannabinoid receptor type 1 (CB1R) and the cannabinoid receptor type 2 (CB2R) are well documented in rodents and primates.

In vervet monkeys, CB1R is present in the retinal neurons (photoreceptors, horizontal cells, bipolar cells, amacrine cells, and ganglion cells) and CB2R is exclusively found in the retinal glia (Müller cells). However, the role of these cannabinoid receptors in normal primate retinal function remains elusive.

Using full-field electroretinography in adult vervet monkeys, we recorded changes in neural activity following the blockade of CB1R and CB2R by the intravitreal administration of their antagonists (AM251 and AM630, resp.) in photopic and scotopic conditions.

Our results show that AM251 increases the photopic a-wave amplitude at high flash intensities, whereas AM630 increases the amplitude of both the photopic a- and b-waves.In scotopic conditions, both blockers increased the b-wave amplitude but did not change the a-wave amplitude.

These findings suggest an important role of CB1R and CB2R in primate retinal function.”

http://www.ncbi.nlm.nih.gov/pubmed/27069692

Analysis of endocannabinoid signaling elements and related proteins in lymphocytes of patients with Dravet syndrome.

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“Cannabidiol (CBD) reduces seizures in childhood epilepsy syndromes including Dravet syndrome (DS).

A formulation of CBD has obtained orphan drug designation for these syndromes and clinical trials are currently underway.

We believe of interest to investigate whether these potential targets are altered in DS, in particular whether the endocannabinoid system is dysregulated. To this end, lymphocytes from patients and controls were used for analysis of gene expression of transmitter receptors and transporters, ion channels, and enzymes associated with CBD effects, as well as endocannabinoid genes.

In conclusion, together with changes in the voltage-dependent calcium channel α-1h subunit, we found an upregulation of CB 2 receptors, associated with an activation of lymphocytes and changes in inflammation-related genes, in DS patients. Such changes were also reported in inflammatory disorders and may indirectly support the occurrence of a potential dysregulation of the endocannabinoid system in the brain.”

http://www.ncbi.nlm.nih.gov/pubmed/27069631

http://www.thctotalhealthcare.com/category/dravet-syndome/

Targeting the cannabinoid CB2 receptor to attenuate the progression of motor deficits in LRRK2-transgenic mice.

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“Most of cases of Parkinson’s disease (PD) have a sporadic origin, with their causes mostly unknown, although overexposure to some environmental factors has been found to occur in some cases. Other forms of parkinsonism are the consequence of dominant or recessive mutations in specific genes, e.g. α-synuclein, parkin and, more recently, leucine-rich repeat kinase 2 (LRRK2), whose G2019S mutation represents the most prevalent form of late-onset, autosomal dominant familial PD.

A transgenic mouse model expressing the G2019S mutation of LRRK2 is already available and apparently may represent a valuable experimental model for investigating PD pathogenesis and novel treatments.

We designed a long-term study with these animals aimed at: (i) elucidating the changes experienced by the endocannabinoid signaling system in the basal ganglia during the progression of the disease in these mice, paying emphasis in the CB2 receptor, which has emerged as a promising target in PD, and (ii) evaluating the potential of compounds selectively activating this CB2 receptor, as disease-modifying agents in these mice.

Our results unequivocally demonstrate that LRRK2 transgenic mice develop motor impairment consisting of small anomalies in rotarod performance (presumably reflecting a deficit in motor coordination and dystonia) and a strong deficiency in the hanging-wire test (reflecting muscle weakness), rather than hypokinesia which was difficult to be demonstrated in the actimeter. These behavioral responses occurred in absence of any evidence of reactive gliosis and neuronal losses, as well as synaptic deterioration in the basal ganglia, except an apparent impairment in autophagy reflected by elevated LAMP-1 immunolabelling in the striatum and substantia nigra.

Furthermore, there were no changes in the status of the CB2 receptor, as well as in other elements of the endocannabinoid signaling, in the basal ganglia, but, paradoxically, the selective activation of this receptor partially reversed the deficits in the hanging-wire test of LRRK2 transgenic mice. This was accompanied by normalization in LAMP-1 immunolabelling in the basal ganglia, although it is possible that other CNS structures, remaining to be identified, are involved in the behavioral improvement.

In summary, our data support the interest of the CB2 receptor as a potential pharmacological target in LRRK2 transgenic mice, although the neuronal substrates underlying these benefits might be not completely related to the basal ganglia and to the presumed parkinsonian features of these mice.”  http://www.ncbi.nlm.nih.gov/pubmed/27063942