Cannabinoid Receptors: An Update on Cell Signaling, Pathophysiological Roles and Therapeutic Opportunities in Neurological, Cardiovascular, and Inflammatory Diseases

ijms-logo “The identification of the human cannabinoid receptors and their roles in health and disease, has been one of the most significant biochemical and pharmacological advancements to have occurred in the past few decades. In spite of the major strides made in furthering endocannabinoid research, therapeutic exploitation of the endocannabinoid system has often been a challenging task.

An impaired endocannabinoid tone often manifests as changes in expression and/or functions of type 1 and/or type 2 cannabinoid receptors. It becomes important to understand how alterations in cannabinoid receptor cellular signaling can lead to disruptions in major physiological and biological functions, as they are often associated with the pathogenesis of several neurological, cardiovascular, metabolic, and inflammatory diseases.

This review focuses mostly on the pathophysiological roles of type 1 and type 2 cannabinoid receptors, and it attempts to integrate both cellular and physiological functions of the cannabinoid receptors. Apart from an updated review of pre-clinical and clinical studies, the adequacy/inadequacy of cannabinoid-based therapeutics in various pathological conditions is also highlighted. Finally, alternative strategies to modulate endocannabinoid tone, and future directions are also emphasized.”

https://pubmed.ncbi.nlm.nih.gov/33080916/

https://www.mdpi.com/1422-0067/21/20/7693

Cannabinoid Combination Induces Cytoplasmic Vacuolation in MCF-7 Breast Cancer Cells

molecules-logo“This study evaluated the synergistic anti-cancer potential of cannabinoid combinations across the MDA-MB-231 and MCF-7 human breast cancer cell lines. Cannabinoids were combined and their synergistic interactions were evaluated using median effect analysis.

The most promising cannabinoid combination (C6) consisted of tetrahydrocannabinol, cannabigerol (CBG), cannabinol (CBN), and cannabidiol (CBD), and displayed favorable dose reduction indices and limited cytotoxicity against the non-cancerous breast cell line, MCF-10A. C6 exerted its effects in the MCF-7 cell line by inducing cell cycle arrest in the G2 phase, followed by the induction of apoptosis.

Morphological observations indicated the induction of cytoplasmic vacuolation, with further investigation suggesting that the vacuole membrane was derived from the endoplasmic reticulum. In addition, lipid accumulation, increased lysosome size, and significant increases in the endoplasmic reticulum chaperone protein glucose-regulated protein 78 (GRP78) expression were also observed.

The selectivity and ability of cannabinoids to halt cancer cell proliferation via pathways resembling apoptosis, autophagy, and paraptosis shows promise for cannabinoid use in standardized breast cancer treatment.”

https://pubmed.ncbi.nlm.nih.gov/33066359/

https://www.mdpi.com/1420-3049/25/20/4682

Industrial, CBD, and Wild Hemp: How Different Are Their Essential Oil Profile and Antimicrobial Activity?

molecules-logo“Hemp (Cannabis sativa L.) is currently one of the most controversial and promising crops. This study compared nine wild hemp (C. sativa spp. spontanea V.) accessions with 13 registered cultivars, eight breeding lines, and one cannabidiol (CBD) hemp strain belonging to C. sativa L.

The first three groups had similar main essential oil (EO) constituents, but in different concentrations; the CBD hemp had a different EO profile. The concentration of the four major constituents in the industrial hemp lines and wild hemp accessions varied as follows: β-caryophyllene 11-22% and 15.4-29.6%; α-humulene 4.4-7.6% and 5.3-11.9%; caryophyllene oxide 8.6-13.7% and 0.2-31.2%; and humulene epoxide 2, 2.3-5.6% and 1.2-9.5%, respectively.

The concentration of CBD in the EO of wild hemp varied from 6.9 to 52.4% of the total oil while CBD in the EO of the registered cultivars varied from 7.1 to 25%; CBD in the EO of the breeding lines and in the CBD strain varied from 6.4 to 25% and 7.4 to 8.8%, respectively. The concentrations of δ9-tetrahydrocannabinol (THC) in the EO of the three groups of hemp were significantly different, with the highest concentration being 3.5%.

The EO of wild hemp had greater antimicrobial activity compared with the EO of registered cultivars.

This is the first report to show that significant amounts of CBD could be accumulated in the EO of wild and registered cultivars of hemp following hydro-distillation. The amount of CBD in the EO can be greater than that in the EO of the USA strain used for commercial production of CBD. Furthermore, this is among the first reports that show greater antimicrobial activity of the EO of wild hemp vs. the EO of registered cultivars.

The results suggest that wild hemp may offer an excellent opportunity for future breeding and the selection of cultivars with a desirable composition of the EO and possibly CBD-rich EO production.”

https://pubmed.ncbi.nlm.nih.gov/33053634/

https://www.mdpi.com/1420-3049/25/20/4631

The immunosuppressive effect of the endocannabinoid system on the inflammatory phenotypes of macrophages and mesenchymal stromal cells: a comparative study

SpringerLink “The inflammatory sequence is the first phase of wound healing. Macrophages (MPhs) and mesenchymal stromal cells (MSCs) respond to an inflammatory microenvironment by adapting their functional activity, which polarizes them into the pro-inflammatory phenotypes M1 and MSC1. Prolongation of the inflammatory phase results in the formation of chronic wounds. The endocannabinoid system (ECS) possesses immunomodulatory properties that may impede this cellular phenotypic switch.

Methods: We investigated the immunosuppressive influence of the endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) on the M1 and MSC1 cytokine secretion. Lipopolysaccharides (LPS) were used as inflammagen to stimulate MPhs and MSCs. Both inflammatory phenotypes were co-exposed to AEA or 2-AG, the specific cannabinoid receptor CB2 agonist JWH-133 served as reference. The inflammatory responses were detected by CD80/163 immuno-labelling and by ELISA measures of secreted IL-6, IL-8, MIF, TNF-α, TGF-β, and VEGF.

Results: M1 cells were found positive for CD80 expression and secreted less IL-6 and IL-8 than MSC1 cells, while both cell types produced similar amounts of MIF. TNF-α release was increased by M1, and growth factors were secreted by MSC1, only. Cannabinoid receptor ligands efficiently decreased the inflammatory response of M1, while their impact was less pronounced in MSC1.

Conclusions: The ECS down-regulated the inflammatory responses of MPhs and MSCs by decreasing the cytokine release upon LPS treatment, while CB2 appeared to be of particular importance. Hence, stimulating the ECS by manipulation of endo- or use of exogenous cannabinoids in vivo may constitute a potent therapeutic option against inflammatory disorders.”

https://pubmed.ncbi.nlm.nih.gov/33026642/

https://link.springer.com/article/10.1007%2Fs43440-020-00166-3

Signaling Through the Type 2 Cannabinoid Receptor Regulates the Severity of Acute and Chronic Graft versus Host Disease

Blood“Graft versus host disease (GVHD) pathophysiology is a complex interplay between cells that comprise the adaptive and innate arms of the immune system. Effective prophylactic strategies are therefore contingent upon approaches that address contributions from both immune cell compartments.

In the current study, we examined the role of the type 2 cannabinoid receptor (CB2R) which is expressed on nearly all immune cells and demonstrated that absence of the CB2R on donor CD4+ or CD8+ T cells, or administration of a selective CB2R pharmacological antagonist, exacerbated acute GVHD lethality. This was accompanied primarily by the expansion of proinflammatory CD8+ T cells indicating that constitutive CB2R expression on T cells preferentially regulated CD8+ T cell alloreactivity. Using a novel CB2R-EGFP reporter mouse, we observed significant loss of CB2R expression on T cells, but not macrophages, during acute GVHD, indicative of differential alterations in receptor expression under inflammatory conditions.

Therapeutic targeting of the CB2R with the agonists, tetrahydrocannabinol (THC) and JWH-133, revealed that only THC mitigated lethal T cell-mediated acute GVHD. Conversely, only JWH-133 was effective in a sclerodermatous chronic GVHD model where macrophages contribute to disease biology. In vitro, both THC and JWH-133 induced arrestin recruitment and ERK phosphorylation via CB2R, but THC had no effect on CB2R-mediated inhibition of adenylyl cyclase.

These studies demonstrate that the CB2R plays a critical role in the regulation of GVHD and suggest that effective therapeutic targeting is dependent upon agonist signaling characteristics and receptor selectivity in conjunction with the composition of pathogenic immune effector cells.”

https://pubmed.ncbi.nlm.nih.gov/33027805/

https://ashpublications.org/blood/article-abstract/doi/10.1182/blood.2020004871/464166/Signaling-Through-the-Type-2-Cannabinoid-Receptor?redirectedFrom=fulltext

The impact of cannabinoid type 2 receptors (CB2Rs) in neuroprotection against neurological disorders

 Acta Pharmacologica Sinica“Cannabinoids have long been used for their psychotropic and possible medical properties of symptom relief. In the past few years, a vast literature shows that cannabinoids are neuroprotective under different pathological situations.

Most of the effects of cannabinoids are mediated by the well-characterized cannabinoid receptors, the cannabinoid type 1 receptor (CB1R) and cannabinoid type 2 receptor (CB2R). Even though CB1Rs are highly expressed in the central nervous system (CNS), the adverse central side effects and the development of tolerance resulting from CB1R activation may ultimately limit the clinical utility of CB1R agonists. In contrast to the ubiquitous presence of CB1Rs, CB2Rs are less commonly expressed in the healthy CNS but highly upregulated in glial cells under neuropathological conditions.

Experimental studies have provided robust evidence that CB2Rs seem to be involved in the modulation of different neurological disorders. In this paper, we summarize the current knowledge regarding the protective effects of CB2R activation against the development of neurological diseases and provide a perspective on the future of this field. A better understanding of the fundamental pharmacology of CB2R activation is essential for the development of clinical applications and the design of novel therapeutic strategies.”

https://pubmed.ncbi.nlm.nih.gov/33024239/

https://www.nature.com/articles/s41401-020-00530-2

The CB2 Agonist β-Caryophyllene in Male and Female Rats Exposed to a Model of Persistent Inflammatory Pain

frontiers – Page 2 – Retraction Watch “Cannabinoids help in pain treatment through their action on CB1 and CB2 receptors.

β-caryophyllene (BCP), an ancient remedy to treat pain, is a sesquiterpene found in large amounts in the essential oils of various spice and food plants such as oregano, cinnamon, and black pepper. It binds to the CB2 receptor, acting as a full agonist.

Sex differences in the BCP-induced analgesic effect were studied by exposing male and female rats to a persistent/repeated painful stimulation.

In conclusion, long-term intake of BCP appears to be able to decrease pain behaviors in a model of repeated inflammatory pain in both sexes, but to a greater degree in males.”

https://pubmed.ncbi.nlm.nih.gov/33013287/

https://www.frontiersin.org/articles/10.3389/fnins.2020.00850/full

“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

“Beta-caryophyllene is a dietary cannabinoid.”   https://www.ncbi.nlm.nih.gov/pubmed/18574142

Endocannabinoids Inhibit the Induction of Virulence in Enteric Pathogens

Cell | Publons
“Endocannabinoids are host-derived lipid hormones that fundamentally impact gastrointestinal (GI) biology. The use of cannabis and other exocannabinoids as anecdotal treatments for various GI disorders inspired the search for mechanisms by which these compounds mediate their effects, which led to the discovery of the mammalian endocannabinoid system. Dysregulated endocannabinoid signaling was linked to inflammation and the gut microbiota. However, the effects of endocannabinoids on host susceptibility to infection has not been explored. Here, we show that mice with elevated levels of the endocannabinoid 2-arachidonoyl glycerol (2-AG) are protected from enteric infection by Enterobacteriaceae pathogens. 2-AG directly modulates pathogen function by inhibiting virulence programs essential for successful infection. Furthermore, 2-AG antagonizes the bacterial receptor QseC, a histidine kinase encoded within the core Enterobacteriaceae genome that promotes the activation of pathogen-associated type three secretion systems. Taken together, our findings establish that endocannabinoids are directly sensed by bacteria and can modulate bacterial function.”
Figure thumbnail fx1

“Fighting intestinal infections with the body’s own endocannabinoids. By harnessing the power of natural compounds produced in the body and in plants, we may eventually treat infections in a whole new way.”  https://www.sciencedaily.com/releases/2020/10/201007123119.htm

“Study may explain why cannabis plant can reduce symptoms of various bowel conditions” https://www.news-medical.net/news/20201007/Study-could-help-explain-why-cannabis-plant-can-reduce-symptoms-of-various-bowel-conditions.aspx

Cancer patients’ experiences with medicinal cannabis-related care

 “Background: Little is known about medical cannabis (MC)-related care for patients with cancer using MC.

Methods: Semistructured telephone interviews were conducted in a convenience sample of individuals (n = 24) with physician-confirmed oncologic diagnoses and state/district authorization to use MC (Arizona, California, Florida, Illinois, Massachusetts, Oregon, New York, and Washington, DC) from April 2017 to March 2019. Standard qualitative techniques were used to assess the degree of MC-related health care oversight, MC practices, and key information sources.

Results: Among 24 participants (median age, 57 years; range, 30-71 years; 16 women [67%]), MC certifications were typically issued by a professional new to a patient’s care after a brief, perfunctory consultation. Patients disclosed MCuse to their established medical teams but received little medical advice about whether and how to use MC. Patients with cancer used MC products as multipurpose symptom management and as cancer-directed therapy, sometimes in lieu of standard-of-care treatments. Personal experimentation, including methodical self-monitoring, was an important source of MC know-how. Absent formal advice from medical professionals, patients relied on nonmedical sources for MC information.

Conclusions: Patients with cancer used MC with minimal medical oversight. Most received MC certifications through brief meetings with unfamiliar professionals. Participants desired but were often unable to access high-quality clinical information about MC from their established medical teams. Because many patients are committed to using MC, a product sustained by a growing industry, medical providers should familiarize themselves with the existing data for MM and its limitations to address a poorly met clinical need.”

https://pubmed.ncbi.nlm.nih.gov/32986266/

“Notably, oncology patients reported using medical cannabis (MC) for symptom management and as cancer‐directed therapy, sometimes instead of traditional treatments.”

https://acsjournals.onlinelibrary.wiley.com/doi/10.1002/cncr.33202

An Agathokakological tale of ∆9 -THC: Exploration of Possible Biological Targets

“∆ 9 -Tetrahydrocannabinol (∆9 -THC), the active phytocannabinoid in cannabis, is virtually an adjunct to the endogenous endocannabinoid signaling system.

By interacting with G-protein-coupled receptors CB1 and CB2, ∆9 -THC affects peripheral and central circulation by lowering sympathetic activity, altering gene expression, cell proliferation, and differentiation, decreasing leukocyte migration, modulating neurotransmitter release thereby modulating cardiovascular functioning, tumorigenesis, immune responses, behavioral and locomotory activities respectively.

∆ 9 -THC is effective in suppressing chemotherapy-induced vomiting, retards malignant tumor growth, inhibits metastasis, and promotes apoptosis. Other mechanisms involved are targeting cell cycle at the G2-M phase in human breast cancer, downregulation of E2F transcription factor 1 (E2F1) in human glioblastoma multiforme, and stimulation of ER stress-induced autophagy.

∆ 9 -THC also plays a role in ameliorating neuroinflammation, excitotoxicity, neuroplasticity, trauma, and stroke and is associated with reliving childhood epilepsy, brain trauma, and neurodegenerative diseases.

∆9 -THC via CB1 receptors affects nociception, emotion, memory, and reduces neuronal excitability and excitotoxicity in epilepsy. It also increases renal blood flow, reduces intraocular pressure via a sympathetic pathway, and modulates hormonal release, thereby decreasing the reproductive function and increasing glucose metabolism.

Versatile medical marijuana has stimulated abundant research demonstrating substantial therapeutic promise, suggesting the possibilities of first-in-class drugs in diverse therapeutic segments. In this review, we represent the current pharmacological status of the phytocannabinoid, ∆ 9 -THC, and synthetic analogs in cancer, cardiovascular, and neurodegenerative disorders.”

https://pubmed.ncbi.nlm.nih.gov/33001012/

https://www.eurekaselect.com/186455/article