Category Archives: Endocannabinoid System

Stimulation of brain glucose uptake by cannabinoid CB2 receptors and its therapeutic potential in Alzheimer’s disease

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“Brain disorders, including Alzheimer’s disease (AD), often involve specific early alterations in the metabolism of glucose in the brain.

The idea of alleviating symptoms of dementia by boosting cerebral energy metabolism has been toyed with for decades, yet safe pharmacological agents with well characterized mechanism of action are still lacking.

In this sense, we have investigated here the local cerebral glucoregulatory potential of the endocannabinoid system in rodents.

Cannabinoid CB2 receptors (CB2Rs) are emerging as important therapeutic targets in brain disorders that typically involve neurometabolic alterations.

Together, these results reveal a novel general glucoregulatory role for CB2Rs in the brain, raising therapeutic interest in CB2R agonists as nootropic agents.

In conclusion, the present results provide the first direct pharmacological evidence in vitroand in vivo of a role of CB2R in central glucoregulation.

Additionally, we found that glucoregulation by endogenous CB2R signalling is negatively affected by β-amyloidosis, thought to be the first pathological step in AD.

Therefore, it would be interesting to perform further studies to define how CB2R mediated glucoregulation contributes to the recently discovered therapeutic potential of CB2R agonists in animal models of AD”

http://www.sciencedirect.com/science/article/pii/S0028390816300879

Novel role of cannabinoid receptor 2 in inhibiting EGF/EGFR and IGF-I/IGF-IR pathways in breast cancer.

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Image result for Oncotarget.“Breast cancer is the second leading cause of cancer deaths among women.

Cannabinoid receptor 2 (CNR2 or CB2) is an integral part of the endocannabinoid system.

Although CNR2 is highly expressed in the breast cancer tissues as well as breast cancer cell lines, its functional role in breast tumorigenesis is not well understood.

We observed that estrogen receptor-α negative (ERα-) breast cancer cells highly express epidermal growth factor receptor (EGFR) as well as insulin-like growth factor-I receptor (IGF-IR). We also observed IGF-IR upregulation in ERα+ breast cancer cells.

In addition, we found that higher CNR2 expression correlates with better recurrence free survival in ERα- and ERα+ breast cancer patients.

Our studies showed that CNR2 activation inhibited EGF and IGF-I-induced migration and invasion of ERα+ and ERα- breast cancer cells.

In conclusion, we show that CNR2 activation suppresses breast cancer through novel mechanisms by inhibiting EGF/EGFR and IGF-I/IGF-IR signaling axes.”

http://www.ncbi.nlm.nih.gov/pubmed/27213582

Cannabinoid receptor 2 as a potential therapeutic target in rheumatoid arthritis

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“Some of cannabinoids, which are chemical compounds contained in marijuana, are immunosuppressive.

One of the receptors, CB receptor 1 (CB1), is expressed predominantly by the cells in the central nervous system, whereas CB receptor 2 (CB2) is expressed primarily by immune cells.

Theoretically, selective CB2 agonists should be devoid of psychoactive effects.

In this study, we investigated therapeutic effects of a selective CB2 agonist on arthritis.

The present study suggests that a selective CB2 agonist could be a new therapy for RA that inhibits production of inflammatory mediators from FLS, and osteoclastogenesis.

This is the first report of therapeutic effect of a selective CB2 agonist on CIA.

Although the effect was mild, optimization of dosage and/or treatment protocol might enhance the effect.

Perhaps, more potent selective CB2agonists might solve this problem.

Cannabinoids are pharmacologically active components of Cannabis sativa.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4243420/

Synthetic cannabinoid receptor agonists and antagonists: implication in CNS disorders.

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“Since the discovery of the cannabinoid receptors, numerous studies associate the endocannabinoid system with several physiological and pathological processes including cancer, appetite, fertility, memory, neuropathic and inflammatory pain, obesity, and neurodegenerative diseases.

Over the last two decades, several researches have been dedicated extensively on the cannabinoid receptors ligands since the direct activation of cannabinoid receptors results in several beneficial effects, in the brain and in the periphery.

During past years, cannabinoid CB1 and CB2 receptor ligands from plants or lab were rapidly developed and then various new structures were reported to be cannabinoids.

The CB1 and CB2 receptor ligands offer several therapeutic opportunities for several CNS-related diseases.

Based on the scientific literature, this review provides an overview of CB1 and CB2 receptor synthetic ligands obtained from drug research and in particular those synthesized for therapeutic purposes and potential clinical applications for central nervous system disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/27193072

Difference and Influence of Inactive and Active States of Cannabinoid Receptor Subtype CB2: From Conformation to Drug Discovery.

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“Cannabinoid receptor 2 (CB2), a G protein-coupled receptor (GPCR), is a promising target for the treatment of neuropathic pain, osteoporosis, immune system, cancer, and drug abuse.”

http://www.ncbi.nlm.nih.gov/pubmed/27186994

Functional selectivity of CB2 cannabinoid receptor ligands at a canonical and non-canonical pathway.

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“The CB2 cannabinoid receptor remains a tantalizing, but unrealized therapeutic target. CB2 receptor ligands belong to varied structural classes and display extreme functional selectivity. Here we have screened diverse CB2 receptor ligands at canonical (inhibition of adenylyl cyclase) and non-canonical (arrestin recruitment) pathways. The non-classical cannabinoid, CP55940 was the most potent agonist for both pathways, while the classical cannabinoid ligand JWH133 was the most efficacious agonist amongst all the ligands profiled in cyclase assays. In the cyclase assay, other classical cannabinoids showed little (Δ9THC, KM233) to no efficacy (L759633 and L759656). Most aminoalkylindoles including WIN55212-2 were moderate efficacy agonists. The cannabilactone AM1710 was equi-efficacious to CP55940 to inhibit adenylyl cyclase, albeit with lower potency. In the arrestin recruitment assays, all classical cannabinoid ligands failed to recruit arrestins, indicating a bias towards G protein coupling for this class of compound. All aminoalkylindoles tested, except for WIN55212-2 and UR144, failed to recruit arrestin. WIN55212-2 was a low efficacy agonist for arrestin recruitment, while UR144 was arrestin biased with no significant inhibition of cyclase. Endocannabinoids were G protein biased with no arrestin recruitment. The diarylpyrazole antagonist, SR144528 was an inverse agonist in cyclase and arrestin recruitment assays while the aminoalkylindole AM630 and carboxamide JTE907 were inverse agonists in cyclase but low efficacy agonists in arrestin recruitment assays. Thus CB2 receptor ligands display strong and varied functional selectivity at both pathways. Therefore extreme care must be exercised when using these compounds to infer the role of CB2 receptors in vivo.”

http://www.ncbi.nlm.nih.gov/pubmed/27194477

Opposite roles of cannabinoid receptors 1 and 2 in hepatocarcinogenesis.

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“The endocannabinoid system (ECS) exerts key roles in the development of liver fibrosis and fatty liver, two diseases that promote the development of hepatocellular carcinoma (HCC).

Although cannabinoids exert potent antitumour effects in vitro, the contribution of the ECS to carcinogenesis in vivo remains elusive.

CONCLUSIONS:

Similar to their role in fibrogenesis, CB1 and CB2 exert opposite effects on hepatocarcinogenesis and may provide novel therapeutic targets.”

http://www.ncbi.nlm.nih.gov/pubmed/27196571

A Central Move for CB2 Receptors.

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“The function of the CB2 cannabinoid receptor in the brain has long been a matter of debate. In this issue of Neuron, Stempel et al. (2016) describe a mechanism whereby endocannabinoid production leads to a cell-intrinsic hyperpolarization that controls self activity.”

http://www.ncbi.nlm.nih.gov/pubmed/27196970

MicroRNA let-7d is a target of cannabinoid CB1 receptor and controls cannabinoid signaling.

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“Cannabinoid CB1 receptor, the molecular target of endocannabinoids and cannabis active components, is one of the most abundant metabotropic receptors in the brain. Cannabis is widely used for both recreational and medicinal purposes.

Despite the ever-growing fundamental roles of microRNAs in the brain, the possible molecular connections between the CB1 receptor and microRNAs are surprisingly unknown. Here, by using reporter gene constructs that express interaction sequences for microRNAs in human SH-SY5Y neuroblastoma cells, we show that CB1 receptor activation enhances the expression of several microRNAs, including let-7d.

Taken together, these findings provide the first evidence for a bidirectional link between the CB1 receptor and a microRNA, namely let-7d, and thus unveil a new player in the complex process of cannabinoid action.”

http://www.ncbi.nlm.nih.gov/pubmed/27179908

Interactions between cannabinoid receptor agonists and mu opioid receptor agonists in rhesus monkeys discriminating fentanyl.

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“Cannabinoid receptor agonists such as delta-9-tetrahydrocannabinol (Δ9-THC) enhance some (antinociceptive) but not other (positive reinforcing) effects of mu opioid receptor agonists, suggesting that cannabinoids might be combined with opioids to treat pain without increasing, and possibly decreasing, abuse.

These data indicate that the discriminative stimulus effects of nalbuphine are more sensitive to attenuation by cannabinoids than those of fentanyl. That the discriminative stimulus effects of some opioids are more susceptible to modification by drugs from other classes has implications for developing maximally effective therapeutic drug mixtures with reduced abuse liability.”

http://www.ncbi.nlm.nih.gov/pubmed/27184925