Leveraging allostery to improve G protein-coupled receptor (GPCR)-directed therapeutics: cannabinoid receptor 1 as a discovery target.

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“Allosteric modulators of G-protein coupled receptors (GPCRs) hold the promise of improved pharmacology and safety over typical orthosteric GPCR ligands.

These features are particularly relevant to the cannabinoid receptor 1 (CB1R) GPCR, since typical orthosteric CB1R ligands are associated with adverse events that limit their translational potential.

Areas covered: The contextual basis for applying allostery to CB1R is considered from pharmacological, drug-discovery, and medicinal standpoints.

Rational design of small-molecule CB1R allosteric modulators as potential pharmacotherapeutics would be greatly facilitated by direct experimental characterization of structure-function correlates underlying the biological activity of chemically-diverse CB1R allosteric modulators, CB1R allosteric ligand-binding binding pockets, and amino acid contact residues critical to allosteric ligand engagement and activity.

In these regards, designer covalent probes exhibiting well-characterized molecular pharmacology as CB1R allosteric modulators are emerging as valuable molecular reporters enabling experimental interrogation of CB1R allosteric site(s) and informing the design of new CB1R agents as drugs.

Expert opinion: Synthesis and pharmacological profiling of CB1R allosteric ligands will continue to provide valuable insights into CB1R structure-function correlates. The resulting data should expand the repertoire of novel agents capable of exerting therapeutic benefit by modulating CB1R-dependent signaling.”

 https://www.ncbi.nlm.nih.gov/pubmed/27712124

Cannabinoids and GI Disorders: Endogenous and Exogenous.

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“Despite the political and social controversy affiliated with it, the medical community must come to the realization that cannabinoids exist as a ubiquitous signaling system in many organ systems. Our understanding of cannabinoids and how they relate not only to homeostasis but also in disease states must be furthered through research, both clinically and in the laboratory. The identification of the cannabinoid receptors in the early 1990s have provided us with the perfect target of translational research. Already, much has been done with cannabinoids and the nervous system. Here, we explore the implications it has for the gastrointestinal tract. Most therapeutics currently on the market presently target only one aspect of the cannabinoid system. Our main purpose here is to highlight areas of research and potential avenues of discovery that the cannabinoid system has yet to reveal.”

https://www.ncbi.nlm.nih.gov/pubmed/27699625

Cannabinoid CB1 receptors in distinct circuits of the extended amygdala determine fear responsiveness to unpredictable threat.

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“The brain circuits underlying behavioral fear have been extensively studied over the last decades.

Here, we show that the endocannabinoid system acting in synaptic circuits of the extended amygdala can explain the fear response profile during exposure to unpredictable threat.

Using fear training with predictable or unpredictable cues in mice, combined with local and cell-type-specific deficiency and rescue of cannabinoid type 1 (CB1) receptors, we found that presynaptic CB1 receptors on distinct amygdala projections to bed nucleus of the stria terminalis (BNST) are both necessary and sufficient for the shift from phasic to sustained fear in response to an unpredictable threat.

These results thereby identify the causal role of a defined protein in a distinct brain pathway for the temporal development of a sustained state of anxious apprehension during unpredictability of environmental influences, reminiscent of anxiety symptoms in humans.”

https://www.ncbi.nlm.nih.gov/pubmed/27698427

Cannabisol, a novel Δ9-THC dimer possessing a unique methylene bridge, isolated from Cannabis sativa.

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“Cannabisol (1), a unique dimer of Δ9-tetrahydrocannabinol (Δ9-THC) with a methylene bridge, was isolated from Cannabis sativa.

This is the first example of a C-bridged dimeric cannabinoid.

The structure of 1 was unambiguously deduced by HRESIMS, GCMS, and NMR spectroscopy.

A plausible biogenesis of 1 is described.”

 https://www.ncbi.nlm.nih.gov/pubmed/27695140

Cannabidiol as a new treatment for drug-resistant epilepsy in tuberous sclerosis complex.

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“Tuberous sclerosis complex (TSC) is an autosomal-dominant genetic disorder with highly variable expression.

The most common neurologic manifestation of TSC is epilepsy, which affects approximately 85% of patients, 63% of whom develop treatment-resistant epilepsy.

Herein, we evaluate the efficacy, safety, and tolerability of cannabidiol (CBD), a nonpsychoactive compound derived from the marijuana plant, as an adjunct to current antiepileptic drugs in patients with refractory seizures in the setting of TSC.

Although double-blind, placebo-controlled trials are still necessary, these findings suggest that cannabidiol may be an effective and well-tolerated treatment option for patients with refractory seizures in TSC.”

https://www.ncbi.nlm.nih.gov/pubmed/27696387

Vascular Dysfunction in a Transgenic Model of Alzheimer’s Disease: Effects of CB1R and CB2R Cannabinoid Agonists.

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“There is evidence of altered vascular function, including cerebrovascular, in Alzheimer’s disease (AD) and transgenic models of the disease.

Indeed vasoconstrictor responses are increased, while vasodilation is reduced in both conditions. β-Amyloid (Aβ) appears to be responsible, at least in part, of alterations in vascular function.

Cannabinoids, neuroprotective and anti-inflammatory agents, induce vasodilation both in vivo and in vitro.

We have demonstrated a beneficial effect of cannabinoids in models of AD by preventing glial activation.

In this work we have studied the effects of these compounds on vessel density in amyloid precursor protein (APP) transgenic mice, line 2576, and on altered vascular responses in aortae isolated ring.

In summary, we have confirmed and extended the existence of altered vascular responses in Tg APP mice.

Moreover, our results suggest that treatment with cannabinoids may ameliorate the vascular responses in AD-type pathology.”

 https://www.ncbi.nlm.nih.gov/pubmed/27695396

Acute and chronic effects of cannabidiol on Δ⁹-tetrahydrocannabinol (Δ⁹-THC)-induced disruption in stop signal task performance.

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“Recent clinical and preclinical research has suggested that cannabidiol (CBD) and Δ9-tetrahydrocannabinol (Δ9-THC) have interactive effects on measures of cognition; however, the nature of these interactions is not yet fully characterized.

To address this, we investigated the effects of Δ9-THC and CBD independently and in combination with proposed therapeutic dose ratios of 1:1 and 1:3 Δ9-THC:CBD in adult rhesus monkeys performing a stop signal task (SST).

These results indicate that CBD, when combined with Δ9-THC in clinically available dose ratios, does not exacerbate and, under restricted conditions may even attenuate, Δ9-THC’s behavioral effects.”

https://www.ncbi.nlm.nih.gov/pubmed/27690502

Turning Down the Thermostat: Modulating the Endocannabinoid System in Ocular Inflammation and Pain.

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“The endocannabinoid system (ECS) has emerged as an important regulator of both physiological and pathological processes. Notably, this endogenous system plays a key role in the modulation of pain and inflammation in a number of tissues.

The components of the ECS, including endocannabinoids, their cognate enzymes and cannabinoid receptors, are localized in the eye, and evidence indicates that ECS modulation plays a role in ocular disease states.

Of these diseases, ocular inflammation presents a significant medical problem, given that current clinical treatments can be ineffective or are associated with intolerable side-effects. Furthermore, a prominent comorbidity of ocular inflammation is pain, including neuropathic pain, for which therapeutic options remain limited.

Recent evidence supports the use of drugs targeting the ECS for the treatment of ocular inflammation and pain in animal models; however, the potential for therapeutic use of cannabinoid drugs in the eye has not been thoroughly investigated at this time.

This review will highlight evidence from experimental studies identifying components of the ocular ECS and discuss the functional role of the ECS during different ocular inflammatory disease states, including uveitis and corneal keratitis.

Candidate ECS targeted therapies will be discussed, drawing on experimental results obtained from both ocular and non-ocular tissue(s), together with their potential application for the treatment of ocular inflammation and pain.”

https://www.ncbi.nlm.nih.gov/pubmed/27695415

β-caryophyllene and β-caryophyllene oxide-natural compounds of anticancer and analgesic properties.

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Cancer Biology & Medicine

“Natural bicyclic sesquiterpenes, β-caryophyllene (BCP) and β-caryophyllene oxide (BCPO), are present in a large number of plants worldwide.

Both BCP and BCPO (BCP(O)) possess significant anticancer activities, affecting growth and proliferation of numerous cancer cells.

In addition, both compounds potentiate the classical drug efficacy by augmenting their concentrations inside the cells.

BCP is a phytocannabinoid with strong affinity to cannabinoid receptor type 2 (CB2 ), but not cannabinoid receptor type 1 (CB1 ). In opposite, BCP oxidation derivative, BCPO, does not exhibit CB1/2 binding, thus the mechanism of its action is not related to endocannabinoid system (ECS) machinery.

It is known that BCPO alters several key pathways for cancer development, such as mitogen-activated protein kinase (MAPK), PI3K/AKT/mTOR/S6K1 and STAT3 pathways. In addition, treatment with this compound reduces the expression of procancer genes/proteins, while increases the levels of those with proapoptotic properties.

The selective activation of CB2 may be considered a novel strategy in pain treatment, devoid of psychoactive side effects associated with CB1 stimulation. Thus, BCP as selective CB2 activator may be taken into account as potential natural analgesic drug.

Moreover, due to the fact that chronic pain is often an element of cancer disease, the double activity of BCP, anticancer and analgesic, as well as its beneficial influence on the efficacy of classical chemotherapeutics, is particularly valuable in oncology.

This review is focused on anticancer and analgesic activities of BCP and BCPO, the mechanisms of their actions, and potential therapeutic utility.”

https://www.ncbi.nlm.nih.gov/pubmed/27696789

“β-caryophyllene (BCP) is a common constitute of the essential oils of numerous spice, food plants and major component in Cannabis.”  http://www.ncbi.nlm.nih.gov/pubmed/23138934

Anandamide Suppresses Proinflammatory T Cell Responses In Vitro through Type-1 Cannabinoid Receptor-Mediated mTOR Inhibition in Human Keratinocytes.

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“The endocannabinoid system comprises cannabinoid receptors 1 and 2 (CB1 and CB2), their endogenous ligands, anandamide (AEA) and 2-arachidonoylglycerol, and metabolic enzymes of these ligands.

The endocannabinoid system has recently been implicated in the regulation of various pathophysiological processes of the skin that include immune competence and/or tolerance of keratinocytes, the disruption of which might promote the development of skin diseases.

Recent evidence showed that CB1 in keratinocytes limits the secretion of proinflammatory chemokines, suggesting that this receptor might also regulate T cell dependent inflammatory diseases of the skin.

In this article, we sought to investigate the cytokine profile of IFN-γ-activated keratinocytes, and found that CB1 activation by AEA suppressed production and release of signature TH1- and TH17-polarizing cytokines, IL-12 and IL-23, respectively. We also set up cocultures between a conditioned medium of treated keratinocytes and naive T cells to disclose the molecular details that regulate the activation of highly proinflammatory TH1 and TH17 cells.

AEA-treated keratinocytes showed reduced an induction of IFN-γ-producing TH1 and IL-17-producing TH17 cells, and these effects were reverted by pharmacological inhibition of CB1.

Further analyses identified mammalian target of rapamycin as a proinflammatory signaling pathway regulated by CB1, able to promote either IL-12 and IL-23 release from keratinocytes or TH1 and TH17 polarization.

Taken together, these findings demonstrate that AEA suppresses highly pathogenic T cell subsets through CB1-mediated mammalian target of rapamycin inhibition in human keratinocytes.

Thus, it can be speculated that the latter pathway might be beneficial to the physiological function of the skin, and can be targeted toward inflammation-related skin diseases.”

https://www.ncbi.nlm.nih.gov/pubmed/27694494