Structural basis of signaling of cannabinoids receptors: paving a way for rational drug design in controling mutiple neurological and immune diseases

Dundee University rank & funding : Compute Scotland“Cannabinoids (CBs), analgesic drugs used for thousands of years, were first found in Cannabis sativa, and the multiple CBs used medicinally, such as tetrahydrocannabinol (THC), cannabidiol (CBD) and dozens more, have complex structures. In addition to their production by plants, CBs are naturally present in the nerves and immune systems of humans and animals.

Both exogenous and endogenous CBs carry out a variety of physiological functions by engaging with two CB receptors, the CB1 and CB2 receptors, in the human endocannabinoid system (ECS). Both CB1 and CB2 are G protein-coupled receptors that share a 7-transmembrane (7TM) topology. CB1, known as the central CB receptor, is mainly distributed in the brain, spinal cord, and peripheral nervous system. CB1 activation in the human body typically promotes the release of neurotransmitters, controls pain and memory learning, and regulates metabolism and the cardiovascular system.

Clinically, CB1 is a direct drug target for drug addiction, neurodegenerative diseases, pain, epilepsy, and obesity. Unlike the exclusive expression of CB1 in the nervous system, CB2 is mainly distributed in peripheral immune cells. Selective CB2 agonists would have therapeutic potential in the treatment of inflammation and pain and avoid side effects caused by currently used clinical drugs.

Although significant progress has been made in developing agonists toward CB receptors, efficient clinical drugs targeting CB receptors remain lacking due to their complex signaling mechanisms. The recent structural elucidation of CB receptors has greatly aided our understanding of the activation and signal transduction mechanisms of CB receptors.

Recent structural characterizations of CB receptors will greatly facilitate the design of new ligands to modulate the selective functions of CB receptors. Notably, the CBD was approved by the Food and Drug Administration (FDA) in 2018 to treat epilepsy. We now look forward to more drugs targeting these two CB receptors for clinical usage in the near future.”

https://pubmed.ncbi.nlm.nih.gov/32694501/

https://www.nature.com/articles/s41392-020-00240-5

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Naturally Occurring Cannabinoids and their Role in Modulation of Cardiovascular Health

 Publication Cover“In recent years, the role of the endocannabinoid system (ECS) in various cardiovascular conditions has been a subject of great interest. The ECS is composed of cannabinoid receptors, their endogenous ligands, also known as endocannabinoids, and enzymes responsible for the synthesis and degradation of endocannabinoids.

Several lines of evidence suggest that the ECS plays a complex role in cardiac and vascular systems; however, under normal physiological conditions the functions of the ECS are limited. Overactivation of components of the ECS has been associated with various cardiovascular conditions.

Intriguingly, activation of the ECS may also reflect a cardioprotective compensatory mechanism. With this knowledge, a range of naturally occurring and synthetic cannabinoid receptor agonists and antagonists, as well as inhibitors of endocannabinoid metabolic enzymes have emerged as promising approaches for the treatment or management of cardiovascular health.

This review will first focus on the known role of the ECS in regulating the cardiovascular system. Secondly, we discuss emerging data highlighting the therapeutic potential of naturally occurring non-psychoactive ECS modulators within the cardiovascular system, including phytocannabinoids, terpenes, and the endocannabinoid-like molecule palmitoylethanolamide.”

https://pubmed.ncbi.nlm.nih.gov/32677481/

“Several approaches discussed here, including administration of eCB-related molecules such as PEA, or supplementing with various phytocannabinoids can be promising candidates for the management of cardiovascular risk factors and CVD.”

https://www.tandfonline.com/doi/full/10.1080/19390211.2020.1790708

The Pro-neurogenic Effects of Cannabidiol and Its Potential Therapeutic Implications in Psychiatric Disorders

Archive of "Frontiers in Behavioral Neuroscience". “During the last decades, researchers have investigated the functional relevance of adult hippocampal neurogenesis in normal brain function as well as in the pathogenesis of diverse psychiatric conditions.

Although the underlying mechanisms of newborn neuron differentiation and circuit integration have yet to be fully elucidated, considerable evidence suggests that the endocannabinoid system plays a pivotal role throughout the processes of adult neurogenesis. Thus, synthetic, and natural cannabinoid compounds targeting the endocannabinoid system have been utilized to modulate the proliferation and survival of neural progenitor cells and immature neurons.

Cannabidiol (CBD), a constituent of the Cannabis Sativa plant, interacts with the endocannabinoid system by inhibiting fatty acid amide hydrolase (FAAH) activity (the rate-limiting enzyme for anandamide hydrolysis), allosterically modulating CB1 and CB2 receptors, and activating components of the “extended endocannabinoid system.” Congruently, CBD has shown prominent pro-neurogenic effects, and, unlike Δ9-tetrahydrocannabinol, it has the advantage of being devoid of psychotomimetic effects.

Here, we first review pre-clinical studies supporting the facilitating effects of CBD on adult hippocampal neurogenesis and available data disclosing cannabinoid mechanisms by which CBD can induce neural proliferation and differentiation. We then review the respective implications for its neuroprotective, anxiolytic, anti-depressant, and anti-reward actions.

In conclusion, accumulating evidence reveals that, in rodents, adult neurogenesis is key to understand the behavioral manifestation of symptomatology related to different mental disorders. Hence, understanding how CBD promotes adult neurogenesis in rodents could shed light upon translational therapeutic strategies aimed to ameliorate psychiatric symptomatology dependent on hippocampal function in humans.”

https://pubmed.ncbi.nlm.nih.gov/32676014/

https://www.frontiersin.org/articles/10.3389/fnbeh.2020.00109/full

The endocannabinoid system

Essays in Biochemistry “Thirty years ago, the discovery of a cannabinoid (CB) receptor that interacts with the psychoactive compound in Cannabis led to the identification of anandamide, an endogenous receptor ligand or endocannabinoid. Research on endocannabinoids has since exploded, and additional receptors along with their lipid mediators and signaling pathways continue to be revealed. Specifically, in humans, the release of endocannabinoids from membrane lipids occurs on demand and the signaling process is rapidly attenuated by the breakdown of the ligand suggesting a tight regulation of the endocannabinoid system (ECS). Additionally, the varying distribution of CB receptors between the central nervous system and other tissues allows for the ECS to participate in a wide range of cognitive and physiological processes. Select plant-derived ‘phyto’cannabinoids such as Δ-9-tetrahydrocannabinol (Δ9-THC) bind to the CB receptors and trigger the ECS, and in the case of Δ9-THC, while it has therapeutic value, can also produce detrimental effects. Current research is aimed at the identification of additional phytocannabinoids with minimal psychotropic effects with potential for therapeutic development. Although decades of research on the ECS and its components have expanded our understanding of the mechanisms and implications of endocannabinoid signaling in mammals, it continues to evolve. Here, we provide a brief overview of the ECS and its overlap with other related lipid-mediated signaling pathways.”

https://pubmed.ncbi.nlm.nih.gov/32648908/

“Therapeutic intervention in the dysregulation of the ECS will no doubt involve new phytocannabinoids and various synthetic CBs with which to control an increasing list of ECS- related pathologies.”

https://portlandpress.com/essaysbiochem/article/doi/10.1042/EBC20190086/225762/The-endocannabinoid-system

Anandamide and 2-AG are the principal endogenous ligands that define the classical endocannabinoid signaling system (ECS).

Receptor Mechanisms Mediating the Anti-Neuroinflammatory Effects of Endocannabinoid System Modulation in a Rat Model of Migraine

European Jnl of Neuroscience – Applications sur Google Play

“Calcitonin gene-related peptide (CGRP), substance-P and dural mast cells are main contributors in neurogenic inflammation underlying migraine pathophysiology.

Modulation of endocannabinoid system attenuates migraine pain, but its mechanisms of action remains unclear.

We investigated receptor mechanisms mediating anti-neuroinflammatory effects of endocannabinoid system modulation in in-vivo migraine model and ex-vivo hemiskull preparations in rats.

Selective ligands targeting CB1 and CB2 receptors may provide novel and effective treatment strategies against migraine.”

https://pubmed.ncbi.nlm.nih.gov/32639078/

https://onlinelibrary.wiley.com/doi/abs/10.1111/ejn.14897

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

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

Use of Cannabis for Agitation in Patients With Dementia

 logo“Studies have reported changes in the endocannabinoid system in the brain of patients with Alzheimer’s disease (AD), playing a role in the pathophysiology of AD. Cannabinoids have been shown to have neuroprotective properties, reduce neuroinflammation, and enhance neurogenesis. Evidence suggests that the utilization of marijuana products containing both tetrahydrocannabinol (THC) and cannabidiol (CBD) or CBD alone have been effective and safe for use in older people with agitation associated with dementia.

A review in 2017 summarized positive findings for therapeutic benefits of cannabinoids in agitation of AD and dementia, but there was no definitive conclusion because of varying cannabinoid products. Cannabinoids were shown to be well tolerated, with few short-term side effects. This differs from first-line medications utilized for dementia behaviors, which can have unwanted side effects. Further research regarding the safety, efficacy, and variability of these products in older people is needed.”

https://pubmed.ncbi.nlm.nih.gov/32600509/

https://www.ingentaconnect.com/content/ascp/tscp/2020/00000035/00000007/art00006;jsessionid=1ivcuvrvy4g1s.x-ic-live-03

Cannabis, the Endocannabinoid System and Immunity-the Journey From the Bedside to the Bench and Back

ijms-logo“The Cannabis plant contains numerous components, including cannabinoids and other active molecules. The phyto-cannabinoid activity is mediated by the endocannabinoid system. Cannabinoids affect the nervous system and play significant roles in the regulation of the immune system.

While Cannabis is not yet registered as a drug, the potential of cannabinoid-based medicines for the treatment of various conditions has led many countries to authorize their clinical use. However, the data from basic and medical research dedicated to medical Cannabis is currently limited.

A variety of pathological conditions involve dysregulation of the immune system. For example, in cancer, immune surveillance and cancer immuno-editing result in immune tolerance. On the other hand, in autoimmune diseases increased immune activity causes tissue damage.

Immuno-modulating therapies can regulate the immune system and therefore the immune-regulatory properties of cannabinoids, suggest their use in the therapy of immune related disorders.

In this contemporary review, we discuss the roles of the endocannabinoid system in immunity and explore the emerging data about the effects of cannabinoids on the immune response in different pathologies. In addition, we discuss the complexities of using cannabinoid-based treatments in each of these conditions.”

https://pubmed.ncbi.nlm.nih.gov/32585801/

https://www.mdpi.com/1422-0067/21/12/4448

Non-opioid Analgesics and the Endocannabinoid System

 Balkan Medical Journal“Non-steroidal anti-inflammatory drugs (NSAIDs) are known to produce antinociceptive effects mainly through peripheral COX-inhibition. Paracetamol and dipyrone are different from classical NSAIDs, because they exert weak anti-inflammatory activity; mechanisms other than peripheral COX inhibition appear to play role in their antinociceptive actions. In this review, we specified classical NSAIDs, paracetamol and dipyrone as “non-opioid analgesics” and discussed the mechanisms mediating participation of the endocannabinoid system in the antinociceptive effects of these analgesics. Non-opioid analgesics and their metabolites may activate cannabinoid receptors. In addition, several mechanisms are implicated in the elevation of endocannabinoid levels following administration of non-opioid analgesics. Of these, reduction of endocannabinoid degradation via FAAH and/or COX-2 inhibition, accumulation of arachidonic acid to endocannabinoid biosynthesis following COX inhibition, inhibition of cellular uptake of endocannabinoids directly or following inhibition of nitric oxide synthase production, and induction of endocannabinoid release are among the proposed mechanisms.”

https://pubmed.ncbi.nlm.nih.gov/32551466/

http://balkanmedicaljournal.org/uploads/pdf/pdf_BMJ_2226.pdf