Cannabinoids and Cannabinoid Receptors: The Story So Far

 iScience journal (@iScience_CP) | Twitter“Like most modern molecular biology and natural product chemistry, understanding cannabinoid pharmacology centers around molecular interactions, in this case, between the cannabinoids and their putative targets, the G-protein coupled receptors (GPCRs) cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2). Understanding the complex structure and interplay between the partners in this molecular dance is required to understand the mechanism of action of synthetic, endogenous, and phytochemical cannabinoids. This review, with 91 references, surveys our understanding of the structural biology of the cannabinoids and their target receptors including both a critical comparison of the extant crystal structures and the computationally derived homology models, as well as an in-depth discussion about the binding modes of the major cannabinoids. The aim is to assist in situating structural biochemists, synthetic chemists, and molecular biologists who are new to the field of cannabis research.”

https://pubmed.ncbi.nlm.nih.gov/32629422/

https://www.cell.com/iscience/pdf/S2589-0042(20)30488-0.pdf?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2589004220304880%3Fshowall%3Dtrue

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The Expression Level of Cannabinoid Receptors Type 1 and 2 in the Different Types of Astrocytomas

 SpringerLink“Astrocytomas, the most prevalent primary brain tumors, can be divided by histology and malignancy levels into four following types: pilocytic astrocytoma (grade I), diffuse fibrillary astrocytoma (grade II), anaplastic astrocytoma (grade III), and glioblastoma multiforme (grade IV). For high grade astrocytomas (grade III and grade IV), blood vessels formation is considered as the most important property.

The distribution of cannabinoid receptors type 1 (CB1) and cannabinoid receptor type 2 (CB2) in blood vessels and tumor tissue of astrocytoma is still controversial. Asrocytoma tissues were collected from 45 patients under the condition of tumor-related neurosurgical operation. The expression of CB1 and CB2 receptors was assessed using immunofluorescence, quantitative real-time RT-PCR and western blotting.

The results indicated an increased expression of CB1 receptors in tumor tissue. There was a significant difference in the mount of CB2 receptors in blood vessels. More was observed in the grade III and glioblastoma (grade IV) than astrocytoma of grade II and control.

This study suggested that, the expression increase of cannabinoid receptors is an index for astrocytoma malignancy and can be targeted as a therapeutic approach for the inhibition of astrocytoma growth among patients.”

https://pubmed.ncbi.nlm.nih.gov/32623617/

https://link.springer.com/article/10.1007%2Fs11033-020-05636-8

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The Role of Cannabinoids in Allergic Diseases

 International Archives of Allergy and Immunology - Home - Karger ...“The human endocannabinoid system (ECS) is a complex signalling network involved in many key physiological processes. The ECS includes the cannabinoid receptors, the endocannabinoid ligands, and the enzymes related to their synthesis and degradation.

Other cannabinoids encompass the phytocannabinoids from Cannabis sativaL.(marijuana) and the synthetic cannabinoids. Alterations in the ECS are associated with different diseases, including inflammatory and immune-mediated disorders such as allergy.

Allergy is a global health problem of increasing prevalence with high socio-economic impact. Different studies have convincingly demonstrated that cannabinoids play a role in allergy, but their actual contribution is still controversial. It has been shown that cannabinoids exert anti-inflammatory properties in the airways and the skin of allergic patients.

A better understanding of the molecular mechanisms involved in the mode of action of specific cannabinoids and cannabinoid receptors on relevant immune cells under different biological contexts might well contribute to the design of novel strategies for the prevention and treatment of allergic diseases. Future research in this promising emerging field in the context of allergy is warranted for the upcoming years.”

https://pubmed.ncbi.nlm.nih.gov/32526734/

“Different studies have convincingly demonstrated the anti-inflammatory properties exerted by cannabinoids in the airways and the skin in the context of allergic diseases both in mice and humans.”

https://www.karger.com/Article/FullText/508989

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Pharmacological Data of Cannabidiol- And Cannabigerol-Type Phytocannabinoids Acting on Cannabinoid CB 1, CB 2 and CB 1/CB 2 Heteromer Receptors

Pharmacological Research“Background: Recent approved medicines whose active principles are Δ9Tetrahidrocannabinol (Δ9-THC) and/or cannabidiol (CBD) open novel perspectives for other phytocannabinoids also present in Cannabis sativa L. varieties. Furthermore, solid data on the potential benefits of acidic and varinic phytocannabinoids in a variety of diseases are already available. Mode of action of cannabigerol (CBG), cannabidiolic acid (CBDA), cannabigerolic acid (CBGA), cannabidivarin (CBDV) and cannabigerivarin (CBGV) is, to the very least, partial.

Hypothesis/purpose: Cannabinoid CB1 or CB2 receptors, which belong to the G-protein-coupled receptor (GPCR) family, are important mediators of the action of those cannabinoids. Pure CBG, CBDA, CBGA, CBDV and CBGV from Cannabis sativa L. are differentially acting on CB1 or CB2 cannabinoid receptors.

Study design: Determination of the affinity of phytocannabinoids for cannabinoid receptors and functional assessment of effects promoted by these compounds when interacting with cannabinoid receptors.

Methods: A heterologous system expressing the human versions of CB1 and/or CB2 receptors was used. Binding to membranes was measured using radioligands and binding to living cells using a homogenous time resolved fluorescence resonance energy transfer (HTRF) assay. Four different functional outputs were assayed: determination of cAMP levels and of extracellular-signal-related-kinase phosphorylation, label-free dynamic mass redistribution (DMR) and ß-arrestin recruitment.

Results: Affinity of cannabinoids depend on the ligand of reference and may be different in membranes and in living cells. All tested phytocannabinoids have agonist-like behavior but behaved as inverse-agonists in the presence of selective receptor agonists. CBGV displayed enhanced potency in many of the functional outputs. However the most interesting result was a biased signaling that correlated with differential affinity, i.e. the overall results suggest that the binding mode of each ligand leads to specific receptor conformations underlying biased signaling outputs.

Conclusion: Results here reported and the recent elucidation of the three-dimensional structure of CB1 and CB2 receptors help understanding the mechanism of action that might be protective and the molecular drug-receptor interactions underlying biased signaling.”

https://pubmed.ncbi.nlm.nih.gov/32470563/

https://www.sciencedirect.com/science/article/abs/pii/S1043661820312482?via%3Dihub

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Biological potential of varinic-, minor-, and acidic phytocannabinoids.

Pharmacological Research“While natural Δ9-tetrahidrocannabinol (Δ9THC), cannabidiol (CBD), and their therapeutic potential have been extensively researched, some cannabinoids have not been widely investigated.

The present article compiles data from the literature that highlights research on and the therapeutic possibilities of lesser known phytocannabinoids, which we have divided into varinic, acidic, and “minor” (i.e., cannabinoids that are not present in high quantities in common varieties of Cannabis sativa L).

A growing interest in these compounds, which are enriched in some cannabis varieties, has already resulted in enough preclinical information to show that they are promising therapeutic agents for a variety of diseases.

Each phytocannabinoid has a “preferential” mechanism of action, and often target the cannabinoid receptors CB1 and/or CB2. The recent resolution of the structure of cannabinoid receptors demonstrates the atypical nature of cannabinoid binding, and that different binding modes depend on the agonist or partial agonist/inverse agonist, which allows for differential signaling, even acting on the same cannabinoid receptor. In addition, other players and multiple signaling pathways may be targeted/engaged by phytocannabinoids, thereby expanding the mechanistic possibilities for therapeutic use.”

https://www.ncbi.nlm.nih.gov/pubmed/32416215

https://www.sciencedirect.com/science/article/abs/pii/S1043661820311099?via%3Dihub

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Targeting the Endocannabinoid System in Borderline Personality Disorder.

“Borderline Personality Disorder (BPD) is a chronic debilitating psychiatric disorder characterized mainly by emotional instability, chaotic interpersonal relationships, cognitive disturbance (e.g. dissociation and suicidal thoughts) and maladaptive behaviors. BPD has a high rate of comorbidity with other mental disorders and high burden on society.

In this review, we focus on two compromised brain regions in BPD – the hypothalamus and the corticolimbic system, emphasizing the involvement and potential contribution of the endocannabinoid system (ECS) to improvement in symptoms and coping.

The hypothalamus-regulated endocrine axes (hypothalamic pituitary – gonadal, thyroid & adrenal) have been found to be dysregulated in BPD. There is also substantial evidence for limbic system structural and functional changes in BPD, especially in amygdala and hippocampus, including cortical regions within the corticolimbic system.

Extensive expression of CB1 and CB2 receptors of the ECS has been found in limbic regions and the hypothalamus. This opens new windows of opportunity for treatment with cannabinoids such as cannabidiol (CBD) as no other pharmacological treatment has shown long-lasting improvement in the BPD population to date.

This review aims to show the potential role of the ECS in BPD patients through their most affected brain regions, the hypothalamus and the corticolimbic system. The literature reviewed does not allow for general indications of treatment with CBD in BPD. However, there is enough knowledge to indicate a treatment ratio of high level of CBD to low level of THC.

A randomized controlled trial investigating the efficacy of cannabinoid based treatments in BPD is warranted.”

https://www.ncbi.nlm.nih.gov/pubmed/32351183

http://www.eurekaselect.com/181504/article

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Can Hemp Help? Low-THC Cannabis and Non-THC Cannabinoids for the Treatment of Cancer.

cancers-logo“Cannabis has been used to relieve the symptoms of disease for thousands of years. However, social and political biases have limited effective interrogation of the potential benefits of cannabis and polarised public opinion.

Evidence is emerging for the therapeutic benefits of cannabis in the treatment of neurological and neurodegenerative diseases, with potential efficacy as an analgesic and antiemetic for the management of cancer-related pain and treatment-related nausea and vomiting, respectively.

An increasing number of preclinical studies have established that ∆9-THC can inhibit the growth and proliferation of cancerous cells through the modulation of cannabinoid receptors (CB1R and CB2R), but clinical confirmation remains lacking.

In parallel, the anti-cancer properties of non-THC cannabinoids, such as cannabidiol (CBD), are linked to the modulation of non-CB1R/CB2R G-protein-coupled receptors, neurotransmitter receptors, and ligand-regulated transcription factors, which together modulate oncogenic signalling and redox homeostasis.

Additional evidence has also demonstrated the anti-inflammatory properties of cannabinoids, and this may prove relevant in the context of peritumoural oedema and the tumour immune microenvironment. This review aims to document the emerging mechanisms of anti-cancer actions of non-THC cannabinoids.”

https://www.ncbi.nlm.nih.gov/pubmed/32340151

https://www.mdpi.com/2072-6694/12/4/1033

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Novel approaches and current challenges with targeting the endocannabinoid system.

 Publication Cover“The pathophysiological relevance of the endocannabinoid system has been widely demonstrated in a variety of diseases including cancer, neurological disorders, and metabolic issues. Therefore, targeting the receptors and the endogenous machinery involved in this system can provide a successful therapeutic outcome.

Ligands targeting the canonical cannabinoid receptors, CB1 and CB2, along with inhibitors of the endocannabinoid enzymes have been thoroughly studied in diverse disease models. In fact, phytocannabinoids such as cannabidiol or Δ9-tetrahydrocannabinol are currently on the market for the management of neuropathic pain due to spasticity in multiple sclerosis or seizures in children epilepsy amongst others.

Expert opinion: Even if orthosteric CB1 and CB2 ligands are on the forefront in cannabinoid clinical research, emerging strategies such as allosteric or biased modulation of these receptors along with controlled off-targets effects may increase the therapeutic potential of cannabinoids.”

https://www.ncbi.nlm.nih.gov/pubmed/32336154

“Multi-target approaches could be promising strategies for the treatment of endocannabinoid system-related disorders. The authors believe that phytocannabinoids are at the forefront of future clinical research.”

https://www.tandfonline.com/doi/abs/10.1080/17460441.2020.1752178?journalCode=iedc20

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Endocannabinoid-Mediated Neuromodulation in the Olfactory Bulb: Functional and Therapeutic Significance.

ijms-logo “Endocannabinoid synthesis in the human body is naturally occurring and on-demand.

It occurs in response to physiological and environmental stimuli, such as stress, anxiety, hunger, other factors negatively disrupting homeostasis, as well as the therapeutic use of the phytocannabinoid cannabidiol and recreational use of exogenous cannabis.

Together with their specific receptors CB1R and CB2R, endocannabinoids are major components of endocannabinoid-mediated neuromodulation in a rapid and sustained manner. Extensive research on endocannabinoid function and expression includes studies in limbic system structures such as the hippocampus and amygdala.

The wide distribution of endocannabinoids, their on-demand synthesis at widely different sites, their co-existence in specific regions of the body, their quantitative differences in tissue type, and different pathological conditions indicate their diverse biological functions that utilize specific and overlapping pathways in multiple organ systems.

Here, we review emerging evidence of these pathways with a special emphasis on the role of endocannabinoids in decelerating neurodegenerative pathology through neural networks initiated by cells in the main olfactory bulb.”

https://www.ncbi.nlm.nih.gov/pubmed/32325875

https://www.mdpi.com/1422-0067/21/8/2850

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Endocannabinoids and Stroke Prevention: Review of Clinical Studies.

View details for Cannabis and Cannabinoid Research cover image“The societal burden of ischemic stroke suggests a need for additional therapeutic categories in stroke prevention.

Modulation of the endocannabinoid system (ECS) is a rational target for stroke prevention because of its effects on inflammation, vascular tone, and metabolic balance, all well-described stroke risk factors.

In this article, we summarize the existing ECS clinical studies in human subjects’ research as they relate to conventional vascular risk factors associated with ischemic stroke.”

https://www.ncbi.nlm.nih.gov/pubmed/32322672

https://www.liebertpub.com/doi/10.1089/can.2018.0066

“The endocannabinoid system and stroke: A focused review. This review seeks to summarize the recent evidence for the role of the endocannabinoid signaling system in stroke pathophysiology, as well as the evidence from preclinical studies regarding the efficacy of cannabinoids as neuroprotective therapies in the treatment of stroke.” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6458776/

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