Exploring the Ligand Efficacy of Cannabinoid Receptor 1 (CB1) using Molecular Dynamics Simulations.

Scientific Reports

“Cannabinoid receptor 1 (CB1) is a promising therapeutic target for a variety of disorders. Distinct efficacy profiles showed different therapeutic effects on CB1 dependent on three classes of ligands: agonists, antagonists, and inverse agonists. To discriminate the distinct efficacy profiles of the ligands, we carried out molecular dynamics (MD) simulations to identify the dynamic behaviors of inactive and active conformations of CB1 structures with the ligands. In addition, the molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) method was applied to analyze the binding free energy decompositions of the CB1-ligand complexes. With these two methods, we found the possibility that the three classes of ligands can be discriminated. Our findings shed light on the understanding of different efficacy profiles of ligands by analyzing the structural behaviors of intact CB1 structures and the binding energies of ligands, thereby yielding insights that are useful for the design of new potent CB1 drugs.”

https://www.ncbi.nlm.nih.gov/pubmed/30213978

https://www.nature.com/articles/s41598-018-31749-z

“Chemical structure of the partial agonist THC, antagonist THCV, and inverse agonist Taranabant.”

Figure 1

Role of the endocannabinoid system in drug addiction.

Biochemical Pharmacology

“Drug addiction is a chronic relapsing disorder that produces a dramaticglobal health burden worldwide. Not effective treatment of drug addiction is currently available probably due to the difficulties to find an appropriate target to manage this complex disease raising the needs for further identification of novel therapeutic approaches.

The endocannabinoid system has been found to play a crucial role in the neurobiological substrate underlying drug addiction.

Endocannabinoids and cannabinoid receptors are widely expressed in the main areas of the mesocorticolimbic system that participate in the initiation and maintenance of drug consumption and in the development of compulsion and loss of behavioral control occurring during drug addiction.

The identification of the important role played by CB1 cannabinoid receptors in drug addiction encouraged the possible used of an early commercialized CB1 receptor antagonist for treating drug addiction.

However, the incidence of serious psychiatric adverse events leaded to the sudden withdrawal from the market of this CB1 antagonist and all the research programs developed by pharmaceutical companies to obtain new CB1 antagonists were stopped.

Currently, new research strategies are under development to target the endocannabinoid system for drug addiction avoiding these side effects, which include allosteric negative modulators of CB1 receptors and compounds targeting CB2 receptors.

Recent studies showing the potential role of CB2 receptors in the addictive properties of different drugs of abuse have open a promising research opportunity to develop novel possible therapeutic approaches.”

https://www.ncbi.nlm.nih.gov/pubmed/30217570

https://www.sciencedirect.com/science/article/abs/pii/S0006295218303952

False-positive cannabinoid screens in adult cystic fibrosis patients treated with lumacaftor/ivacaftor

Journal of Cystic Fibrosis

“Cystic fibrosis (CF) is caused by gene mutations resulting in defective cystic fibrosis transmembrane conductance regulator (CFTR) protein activity. CFTR modulators have been developed to improve CFTR protein function. The combination of ivacaftor (IVA) and lumacaftor (LUM) partially restores CFTR protein function of F508del, the most common CF mutation.”

https://www.ncbi.nlm.nih.gov/pubmed/30217546

“False-positive cannabinoid screens in adult cystic fibrosis patients treated with lumacaftor/ivacaftor”

https://www.cysticfibrosisjournal.com/article/S1569-1993(18)30754-9/fulltext

Oral cannabinoid-rich THC/CBD cannabis extract for secondary prevention of chemotherapy-induced nausea and vomiting: a study protocol for a pilot and definitive randomised double-blind placebo-controlled trial (CannabisCINV).

BMJ Journals

“Chemotherapy-induced nausea and vomiting (CINV) remains an important issue for patients receiving chemotherapy despite guideline-consistent antiemetic therapy. Trials using delta-9-tetrahydrocannabinol-rich (THC) products demonstrate limited antiemetic effect, significant adverse events and flawed study design. Trials using cannabidiol-rich (CBD) products demonstrate improved efficacy and psychological adverse event profile. No definitive trials have been conducted to support the use of cannabinoids for this indication, nor has the potential economic impact of incorporating such regimens into the Australian healthcare system been established. CannabisCINV aims to assess the efficacy, safety and cost-effectiveness of adding TN-TC11M, an oral THC/CBD extract to guideline-consistent antiemetics in the secondary prevention of CINV.

METHODS AND ANALYSIS:

The current multicentre, 1:1 randomised cross-over, placebo-controlled pilot study will recruit 80 adult patients with any malignancy, experiencing CINV during moderate to highly emetogenic chemotherapy despite guideline-consistent antiemetics. Patients receive oral TN-TC11M (THC 2.5mg/CBD 2.5 mg) capsules or placebo capsules three times a day on day -1 to day 5 of cycle A of chemotherapy, followed by the alternative drug regimen during cycle B of chemotherapy and the preferred drug regimen during cycle C. The primary endpoint is the proportion of subjects attaining a complete response to CINV. Secondary and tertiary endpoints include regimen tolerability, impact on quality of life and health system resource use. The primary assessment tool is patient diaries, which are filled from day -1 to day 5. A subsequent randomised placebo-controlled parallel phase III trial will recruit a further 250 patients.

ETHICS AND DISSEMINATION:

The protocol was approved by ethics review committees for all participating sites. Results will be disseminated in peer-reviewed journals and at scientific conferences.”

https://www.ncbi.nlm.nih.gov/pubmed/30209152

https://bmjopen.bmj.com/content/8/9/e020745

Cannabinoid 1 Receptor Signaling on Hippocampal GABAergic Neurons Influences Microglial Activity.

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“Microglia, the resident immune cells of the brain, play important roles in defending the brain against pathogens and supporting neuronal circuit plasticity. Chronic or excessive pro-inflammatory responses of microglia damage neurons, therefore their activity is tightly regulated.

Pharmacological and genetic studies revealed that cannabinoid type 1 (CB1) receptor activity influences microglial activity, although microglial CB1 receptor expression is very low and activity-dependent. The CB1 receptor is mainly expressed on neurons in the central nervous system (CNS)-with an especially high level on GABAergic interneurons.

Here, we determined whether CB1 signaling on this neuronal cell type plays a role in regulating microglial activity.

Our result suggests that CB1 receptor agonists can modulate microglial activity indirectly, through CB1 receptors on GABAergic neurons.

Altogether, we demonstrated that GABAergic neurons, despite their relatively low density in the hippocampus, have a specific role in the regulation of microglial activity and cannabinoid signaling plays an important role in this arrangement.”

https://www.ncbi.nlm.nih.gov/pubmed/30210289

https://www.frontiersin.org/articles/10.3389/fnmol.2018.00295/full

Cannabis sativa: A comprehensive ethnopharmacological review of a medicinal plant with a long history.

Journal of Ethnopharmacology

“Cannabis sativa L. (C. sativa) is an annual dioecious plant, which shares its origins with the inception of the first agricultural human societies in Asia. Over the course of time different parts of the plant have been utilized for therapeutic and recreational purposes, for instance, extraction of healing oils from seed, or the use of inflorescences for their psychoactive effects. The key psychoactive constituent in C. sativa is called Δ-9-tetrahydrocannabinol (D9-THC). The endocannabinoid system seems to be phylogenetically ancient, as it was present in the most primitive vertebrates with a neuronal network. N-arachidonoylethanolamine (AEA) and 2-arachidonoyl glycerol (2-AG) are the main endocannabinoids ligands present in the animal kingdom, and the main endocannabinoid receptors are cannabinoid type-1 (CB1) receptor and cannabinoid type-2 (CB2) receptor.

AIM OF THE STUDY:

The review aims to provide a critical and comprehensive evaluation, from the ancient times to our days, of the ethnological, botanical, chemical and pharmacological aspects of C. sativa, with a vision for promoting further pharmaceutical research to explore its complete potential as a therapeutic agent.

RESULTS AND CONCLUSIONS:

A detailed comparative analysis of the available resources for C. sativa confirmed its origin and traditional spiritual, household and therapeutic uses and most importantly its popularity as a recreational drug. The result of several studies suggested a deeper involvement of phytocannabinoids (the key compounds in C. sativa) in several others central and peripheral pathophysiological mechanisms such as food intake, inflammation, pain, colitis, sleep disorders, neurological and psychiatric illness. However, despite their numerous medicinal benefits, they are still considered as a menace to the society and banned throughout the world, except for few countries. We believe that this review will help lay the foundation for promoting exhaustive pharmacological and pharmaceutical studies in order to better understand the clinical relevance and applications of non-psychoactive cannabinoids in the prevention and treatment of life-threatening diseases and help to improve the legal status of C. sativa.”

https://www.ncbi.nlm.nih.gov/pubmed/30205181

https://www.sciencedirect.com/science/article/pii/S0378874118316611?via%3Dihub

Heterogeneity of cannabinoid ligand-induced modulations in intracellular Ca2+ signals of mouse pancreatic acinar cells in vitro.

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“We recently reported that a CB2R agonist, GW405833 (GW), reduced both the ACh-induced Ca2+ oscillations and the L-arginine-induced Ca2+ signal enhancement in mouse pancreatic acinar cells, suggesting that GW-induced inhibition may prevent the pathogenesis of acute pancreatitis.

In this study, we aim to evaluate the effects of other cannabinoid ligands on Ca2+ signaling in acinar cells.

In conclusion, CB2R agonists play critical roles in modulating Ca2+ signals in mouse pancreatic acinar cells, while other cannabinoid ligands modulate Ca2+ oscillations in a heterogeneous manner through a CB receptor or non-CB-receptor mechanism.”

https://www.ncbi.nlm.nih.gov/pubmed/30202013

Identification of novel mouse and rat CB1R isoforms and in silico modeling of human CB1R for peripheral cannabinoid therapeutics.

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“Targeting peripheral CB1R is desirable for the treatment of metabolic syndromes without adverse neuropsychiatric effects.

We previously reported a human hCB1b isoform that is selectively enriched in pancreatic beta-cells and hepatocytes, providing a potential peripheral therapeutic hCB1R target. It is unknown whether there are peripherally enriched mouse and rat CB1R (mCB1 and rCB1, respectively) isoforms.

In this study, we found no evidence of peripherally enriched rodent CB1 isoforms; however, some mCB1R isoforms are absent in peripheral tissues. We show that the mouse Cnr1 gene contains six exons that are transcribed from a single promoter. We found that mCB1A is a spliced variant of extended exon 1 and protein-coding exon 6; mCB1B is a novel spliced variant containing unspliced exon 1, intron 1, and exon 2, which is then spliced to exon 6; and mCB1C is a spliced variant including all 6 exons.

Using RNAscope in situ hybridization, we show that the isoforms mCB1A and mCB1B are expressed at a cellular level and colocalized in GABAergic neurons in the hippocampus and cortex. RT-qPCR reveals that mCB1A and mCB1B are enriched in the brain, while mCB1B is not expressed in the pancreas or the liver. Rat rCB1R isoforms are differentially expressed in primary cultured neurons, astrocytes, and microglia.

We also investigated modulation of Cnr1 expression by insulin in vivo and carried out in silico modeling of CB1R with JD5037, a peripherally restricted CB1R inverse agonist, using the published crystal structure of hCB1R.

The results provide models for future CB1R peripheral targeting.”

Targeting Glioma Initiating Cells With A Combined Therapy Of Cannabinoids And Temozolomide.

Biochemical Pharmacology

“Glioblastoma multiforme (GBM) is the most frequent and aggressive type of brain tumor due, at least in part, to its poor response to current anticancer treatments. These features could be explained, at least partially, by the presence within the tumor mass of a small population of cells termed Glioma Initiating Cells (GICs) that has been proposed to be responsible for the relapses occurring in this disease. Thus, the development of novel therapeutic approaches (and specifically those targeting the population of GICs) is urgently needed to improve the survival of the patients suffering this devastating disease.

Previous observations by our group and others have shown that Δ9-Tetrahydrocannabinol (THC, the main active ingredient of marijuana) and other cannabinoids including cannabidiol (CBD) exert antitumoral actions in several animal models of cancer, including gliomas.

We also found that the administration of THC (or of THC + CBD at a 1:1 ratio) in combination with temozolomide, the benchmark agent for the treatment of GBM, synergistically reduces the growth of glioma xenografts.

In this work we investigated the effect of the combination of TMZ and THC:CBD mixtures containing different ratios of the two cannabinoids in preclinical glioma models, including those derived from GICs.

Our findings show that TMZ + THC:CBD combinations containing a higher proportion of CDB (but not TMZ + CBD alone) produce a similar antitumoral effect as the administration of TMZ together with THC and CBD at a 1:1 ratio in xenografts generated with glioma cell lines. In addition, we also found that the administration of TMZ + THC:CBD at a 1:1 ratio reduced the growth of orthotopic xenografts generated with GICs derived from GBM patients and enhanced the survival of the animals bearing these intracranial xenografts.

Remarkably, the antitumoral effect observed in GICs-derived xenografts was stronger when TMZ was administered together with cannabinoid combinations containing a higher proportion of CBD. These findings support the notion that the administration of TMZ together with THC:CBD combinations – and specifically those containing a higher proportion of CBD – may be therapeutically explored to target the population of GICs in GBM.”

The Endocannabinoid/Cannabinoid Receptor 2 System Protects Against Cisplatin-Induced Hearing Loss.

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“Previous studies have demonstrated the presence of cannabinoid 2 receptor (CB2R) in the rat cochlea which was induced by cisplatin. In an organ of Corti-derived cell culture model, it was also shown that an agonist of the CB2R protected these cells against cisplatin-induced apoptosis.

In the current study, we determined the distribution of CB2R in the mouse and rat cochleae and examined whether these receptors provide protection against cisplatin-induced hearing loss.

These data unmask a protective role of the cochlear endocannabinoid/CB2R system which appears tonically active under normal conditions to preserve normal hearing. However, an exogenous agonist is needed to boost the activity of endocannabinoid/CB2R system for protection against a more traumatic cochlear insult, as observed with cisplatin administration.”

https://www.ncbi.nlm.nih.gov/pubmed/30186120

https://www.frontiersin.org/articles/10.3389/fncel.2018.00271/full