Endocannabinoid signaling at the periphery: 50 years after THC

Topical cannabis-based medicines - A novel adjuvant treatment for venous leg ulcers: An open-label trial

Venous leg ulcers are highly prevalent lower limb integumentary wounds that remain challenging to heal despite the use of evidence-based compression therapies. A multitude of adjuvant treatments has been studied but none have demonstrated enough efficacy to gain adoption into treatment guidelines. Global attention on Cannabis-Based Therapies is increasing and has been driven by quantum scientific advancements in the understanding of the endocannabinoid signalling system. Topical Cannabis-Based Medicines represent a novel treatment paradigm for venous leg ulcers in terms of promoting wound closure. Fourteen complex patients with sixteen recalcitrant leg ulcers were treated with Topical Cannabis-Based Medicines in conjunction with compression bandaging, every second day, to both wound bed and peri-wound tissues. The cohort had a mean age of 75.8 years and was medically complex as reflected by a mean M3 multimorbidity index score of 2.94 and a mean Palliative Performance Scale score of 67.1%. Complete wound closure, defined as being fully epithelialized, was achieved among 11 patients (79%) and 13 wounds (81%) within a median of 34 days. All three remaining patients demonstrated progressive healing trends but were lost to follow-up. The treatments were well tolerated, and no significant adverse reactions were experienced. The rapid wound closure of previously non-healing venous leg ulcers among elderly and highly complex patients suggests that Topical Cannabis-Based Medicines may become effective adjuvants in conjunction with compression therapy. This may also indicate that they may have an even broader role within integumentary and wound management. Therefore, this treatment paradigm warrants being subjected to controlled trials.

Cannabidiol-Driven Alterations to Inflammatory Protein Landscape of Lipopolysaccharide-Activated Macrophages In Vitro May Be Mediated by Autophagy and Oxidative Stress

Background: The nonpsychotropic phytocannabinoid cannabidiol (CBD) presents itself as a potentially safe and effective anti-inflammatory treatment relative to clinical standards. In this present study, we compare the capacity of CBD to the corticosteroid dexamethasone (Dex) in altering the secreted protein landscape of activated macrophages and speculate upon the mechanism underpinning these alterations. Materials and Methods: Human THP-1 monocytes were differentiated into macrophages (THP-1 derived macrophages [tMACs]), activated with lipopolysaccharide (LPS), and then treated with 5, 10, 25, 50, or 100 μM CBD or 10 μM Dex for 24 h. Following treatment, cytotoxicity of CBD and protein expression levels from culture supernatants and from whole cell lysates were assessed for secreted and intracellular proteins, respectively. Results: High concentration (50 and 100 μM) CBD treatments exhibit a cytotoxic effect on LPS-activated tMACs following the 24-h treatment. Relative to the LPS-activated and untreated control (M[LPS]), both 25 μM CBD and 10 μM Dex reduced expression of pro-inflammatory markers-tumor necrosis factor alpha, interleukin 1 beta, and regulated on activation, normal T cell expressed and secreted (RANTES)-as well as the pleiotropic marker interleukin-6 (IL-6). A similar trend was observed for anti-inflammatory markers interleukin-10 and vascular endothelial growth factor (VEGF). Dex further reduced secreted levels of monocyte chemoattractant protein-1 in addition to suppressing IL-6 and VEGF beyond treatments with CBD. The anti-inflammatory capacity of 25 μM CBD was concurrent with reduction in levels of phosphorylated mammalian target of rapamycin Ser 2448, endothelial nitric oxide synthase, and induction of cyclooxygenase 2 relative to M(LPS). This could suggest that the observed effects on macrophage immune profile may be conferred through inhibition of mammalian target of rapamycin complex 1 and ensuing induction of autophagy. Conclusion: Cumulatively, these data demonstrate cytotoxicity of high concentration CBD treatment. The data reported herein largely agree with other literature demonstrating the anti-inflammatory effects of CBD. However, there is discrepancy within literature surrounding efficacious concentrations and effects of CBD on specific secreted proteins. These data expand upon previous work investigating the effects of CBD on inflammatory protein expression in macrophages, as well as provide insight into the mechanism by which these effects are conferred.

Pro-Inflammatory Cytokines: Potential Links between the Endocannabinoid System and the Kynurenine Pathway in Depression

Substance use/abuse is one of the main causes of depressive symptoms. Cannabis and synthetic cannabinoids in particular gained significant popularity in the past years. There is an increasing amount of clinical data associating such compounds with the inflammatory component of depression, indicated by the up-regulation of pro-inflammatory cytokines. Pro-inflammatory cytokines are also well-known to regulate the enzymes of the kynurenine pathway (KP), which is responsible for metabolizing tryptophan, a precursor in serotonin synthesis. Enhanced pro-inflammatory cytokine levels may over-activate the KP, leading to tryptophan depletion and reduced serotonin levels, which can subsequently precipitate depressive symptoms. Therefore, such mechanism might represent a possible link between the endocannabinoid system (ECS) and the KP in depression, via the inflammatory and dysregulated serotonergic component of the disorder. This review will summarize the data regarding those natural and synthetic cannabinoids that increase pro-inflammatory cytokines. Furthermore, the data on such cytokines associated with KP activation will be further reviewed accordingly. The interaction of the ECS and the KP has been postulated and demonstrated in some studies previously. This review will further contribute to this yet less explored connection and propose the KP to be the missing link between cannabinoid-induced inflammation and depressive symptoms.

Circulating Endocannabinoids as Diagnostic Markers of Canine Chronic Enteropathies: A Pilot Study

Chronic enteropathies (CEs) in dogs, according to the treatment response to consecutive trials, are classified as food-responsive (FRE), antibiotic-responsive (ARE), and immunosuppressive-responsive (IRE) enteropathy. In addition to this classification, dogs with loss of protein across the gut are grouped as protein-losing enteropathy (PLE). At present, the diagnosis of CEs is time-consuming, costly and sometimes invasive, also because non-invasive biomarkers with high sensitivity and specificity are not yet available. Therefore, this study aimed at assessing the levels of circulating endocannabinoids in plasma as potential diagnostic markers of canine CEs. Thirty-three dogs with primary chronic gastrointestinal signs presented to Veterinary Teaching Hospitals of Teramo and Bologna (Italy) were prospectively enrolled in the study, and 30 healthy dogs were included as a control group. Plasma levels of N-arachidonoylethanolamine (AEA), 2-arachidonoylglycerol (2-AG), N-palmitoylethanolamine (PEA), and N-oleoylethanolamine (OEA) were measured at the time of the first visit in dogs with different CEs, as well as in healthy subjects. Plasma levels of 2-AG (p = 0.001) and PEA (p = 0.008) were increased in canine CEs compared to healthy dogs. In particular, PEA levels were increased in the FRE group compared to healthy dogs (p = 0.04), while 2-AG was higher in IRE than in healthy dogs (p = 0.0001). Dogs affected by FRE also showed decreased 2-AG (p = 0.0001) and increased OEA levels (p = 0.0018) compared to IRE dogs. Moreover, dogs with PLE showed increased 2-AG (p = 0.033) and decreased AEA (p = 0.035), OEA (p = 0.016) and PEA (p = 0.023) levels, when compared to dogs affected by CEs without loss of proteins. The areas under ROC curves for circulating 2-AG (0.91; 95% confidence interval [CI], 0.79–1.03) and OEA (0.81; 95% CI, 0.65–0.97) showed a good accuracy in distinguishing the different forms of CEs under study (FRE, ARE and IRE), at the time of the first visit. The present study demonstrated that endocannabinoid signaling is altered in canine CEs, and that CE subtypes showed distinct profiles of 2-AG, PEA and OEA plasma levels, suggesting that these circulating bioactive lipids might have the potential to become candidate biomarkers for canine CEs.

The Interplay between the Immune and the Endocannabinoid Systems in Cancer

The therapeutic potential of Cannabis sativa has been recognized since ancient times. Phytocannabinoids, endocannabinoids and synthetic cannabinoids activate two major G protein-coupled receptors, subtype 1 and 2 (CB1 and CB2). Cannabinoids (CBs) modulate several aspects of cancer cells, such as apoptosis, autophagy, proliferation, migration, epithelial-to-mesenchymal transition and stemness. Moreover, agonists of CB1 and CB2 receptors inhibit angiogenesis and lymphangiogenesis in vitro and in vivo. Low-grade inflammation is a hallmark of cancer in the tumor microenvironment (TME), which contains a plethora of innate and adaptive immune cells. These cells play a central role in tumor initiation and growth and the formation of metastasis. CB2 and, to a lesser extent, CB1 receptors are expressed on a variety of immune cells present in TME (e.g., T cells, macrophages, mast cells, neutrophils, NK cells, dendritic cells, monocytes, eosinophils). The activation of CB receptors modulates a variety of biological effects on cells of the adaptive and innate immune system. The expression of CB2 and CB1 on different subsets of immune cells in TME and hence in tumor development is incompletely characterized. The recent characterization of the human cannabinoid receptor CB2-G_i signaling complex will likely aid to design potent and specific CB2/CB1 ligands with therapeutic potential in cancer.

Cannabinoid Signaling in Auditory Function and Development

Plants of the genus Cannabis have been used by humans for millennia for a variety of purposes. Perhaps most notable is the use of certain Cannabis strains for their psychoactive effects. More recently, several biologically active molecules within the plants of these Cannabis strains, called phytocannabinoids or simply cannabinoids, have been identified. Furthermore, within human cells, endogenous cannabinoids, or endocannabinoids, as well as the receptors and secondary messengers that give rise to their neuromodulatory effects, have also been characterized. This endocannabinoid system (ECS) is composed of two primary ligands-anandamide and 2-arachidonyl glycerol; two primary receptors-cannabinoid receptors 1 and 2; and several enzymes involved in biosynthesis and degradation of endocannabinoid ligands including diacylglycerol lipase (DAGL) and monoacylglycerol lipase (MAGL). Here we briefly summarize cannabinoid signaling and review what has been discerned to date with regard to cannabinoid signaling in the auditory system and its roles in normal physiological function as well as pathological conditions. While much has been uncovered regarding cannabinoid signaling in the central nervous system, less attention has been paid to the auditory system specifically. Still, evidence is emerging to suggest that cannabinoid signaling is critical for the development, maturation, function, and survival of cochlear hair cells (HCs) and spiral ganglion neurons (SGNs). Furthermore, cannabinoid signaling can have profound effects on synaptic connectivity in CNS structures related to auditory processing. While clinical cases demonstrate that endogenous and exogenous cannabinoids impact auditory function, this review highlights several areas, such as SGN development, where more research is warranted.

Chronic Cannabis Users: A New Special Population to Consider for Drug Development

The use and acceptance of cannabis, either medically or recreationally, has substantially outpaced the collection of data necessary to evaluate its use in any population. However, the mere widespread availability does not imply the absence of risk or confirmation of efficacy and should not be treated as such. There is enough data to suggest that not only does the potential for pharmacokinetic and metabolic interactions exist, but also that baseline characteristics for a given population could be different in chronic cannabis users. Either or both of these may impact the safety and efficacy profile for any new drug in development. As such, we encourage drug developers to consider that the cannabis user may very well be a special population that warrants its own clinical pharmacology evaluation.

Synthesis, Molecular Pharmacology, and Structure-Activity Relationships of 3-(Indanoyl)indoles as Selective Cannabinoid Type 2 Receptor Antagonists

Synthetic indole cannabinoids characterized by a 2',2'-dimethylindan-5'-oyl group at the indole C3 position constitute a new class of ligands possessing high affinity for human CB2 receptors at a nanomolar concentration and a good selectivity index. Starting from the neutral antagonist 4, the effects of indole core modification on the pharmacodynamic profile of the ligands were investigated. Several N1 side chains afforded potent and CB2-selective neutral antagonists, notably derivatives 26 (R1 = n-propyl, R2 = H) and 35 (R1 = 4-pentynyl, R2 = H). Addition of a methyl group at C2 improved the selectivity for the CB2 receptor. Moreover, C2 indole substitution may control the CB2 activity as shown by the functionality switch in 35 (antagonist) and 49 (R1 = 4-pentynyl, R2 = CH3, partial agonist).

Authorization Patterns, Safety, and Effectiveness of Medical Cannabis in Quebec

Introduction: Despite increasing demand for data, little is known about the authorization patterns, safety, and effectiveness of medical cannabis products.

Materials and Methods: We conducted a 2 year observational study of adult patients who were legally authorized a medical cannabis product from a single licensed producer; we captured and analyzed authorized cannabis use patterns by cannabinoid profile (tetrahydrocannabinol [THC]-dominant; cannabidiol [CBD]-dominant; and balanced (THC:CBD) and clinical outcomes using standardized outcome measures every 3 months for 12 months at a network of medical cannabis clinics in Quebec, Canada.

Results: We recruited 585 patients (average age 56.5 years), of whom 61% identified as female and 85% reported pain as their primary complaint. Over 12 months, there was a significant increase in the number of products authorized (Z=2.59, p=0.01). The proportion of authorizations for a THC-dominant or CBD-dominant product increased relative to the proportion of authorizations for a balanced (THC:CBD) product (all p<0.01). Symptom improvement over time was observed for pain, tiredness, drowsiness, anxiety, and well-being. Patients authorized THC-dominant products exhibited less symptom improvement for anxiety and well-being relative to those authorized CBD-dominant or balanced (THC:CBD) products. Medical cannabis was well tolerated across all product profiles.

Conclusion: These real-world data reveal changes in medical cannabis authorization patterns and suggest that symptom improvement may vary by cannabinoid profile over 12 months of follow-up.

"Photo-Rimonabant": Synthesis and Biological Evaluation of Novel Photoswitchable Molecules Derived from Rimonabant Lead to a Highly Selective and Nanomolar "Cis-On" CB1R Antagonist

Human cannabinoid receptor type 1 (hCB₁R) plays important roles in the regulation of appetite and development of addictive behaviors. Herein, we describe the design, synthesis, photocharacterization, molecular docking, and in vitro characterization of "photo-rimonabant", i.e., azo-derivatives of the selective hCB₁R antagonist SR1411716A (rimonabant). By applying azo-extension strategies, we yielded compound 16a, which shows marked affinity for CB₁R (K_{i (cis form)} = 29 nM), whose potency increases by illumination with ultraviolet light (CB₁R K_itrans/cis ratio = 15.3). Through radioligand binding, calcium mobilization, and cell luminescence assays, we established that 16a is highly selective for hCB₁R over hCB₂R. These selective antagonists can be valuable molecular tools for optical modulation of CBRs and better understanding of disorders associated with the endocannabinoid system.

Cannabinoid receptor type 2 ligands: an analysis of granted patents since 2010

The G-protein-coupled cannabinoid receptor type 2 (CB2R) is a key element of the endocannabinoid (EC) system. EC/CB2R signaling has significant therapeutic potential in major pathologies affecting humans such as allergies, neurodegenerative disorders, inflammation or ocular diseases. CB2R agonism exerts anti-inflammatory and tissue protective effects in preclinical animal models of cardiovascular, gastrointestinal, liver, kidney, lung and neurodegenerative disorders. Existing ligands can be subdivided into endocannabinoids, cannabinoid-like and synthetic CB2R ligands that possess various degrees of potency on and selectivity against the cannabinoid receptor type 1. This review is an account of granted CB2R ligand patents from 2010 up to the present, which were surveyed using Derwent Innovation®.

Synthesis, Quantification, and Characterization of Fatty Acid Amides from In Vitro and In Vivo Sources

Fatty acid amides are a diverse family of underappreciated, biologically occurring lipids. Herein, the methods for the chemical synthesis and subsequent characterization of specific members of the fatty acid amide family are described. The synthetically prepared fatty acid amides and those obtained commercially are used as standards for the characterization and quantification of the fatty acid amides produced by biological systems, a fatty acid amidome. The fatty acid amidomes from mouse N₁₈TG₂ cells, sheep choroid plexus cells, Drosophila melanogaster, Bombyx mori, Apis mellifera, and Tribolium castaneum are presented.

Cnr2 Is Important for Ribbon Synapse Maturation and Function in Hair Cells and Photoreceptors

The role of the cannabinoid receptor 2 (CNR2) is still poorly described in sensory epithelia. We found strong cnr2 expression in hair cells (HCs) of the inner ear and the lateral line (LL), a superficial sensory structure in fish. Next, we demonstrated that sensory synapses in HCs were severely perturbed in larvae lacking cnr2. Appearance and distribution of presynaptic ribbons and calcium channels (Ca_v1.3) were profoundly altered in mutant animals. Clustering of membrane-associated guanylate kinase (MAGUK) in post-synaptic densities (PSDs) was also heavily affected, suggesting a role for cnr2 for maintaining the sensory synapse. Furthermore, vesicular trafficking in HCs was strongly perturbed suggesting a retrograde action of the endocannabinoid system (ECs) via cnr2 that was modulating HC mechanotransduction. We found similar perturbations in retinal ribbon synapses. Finally, we showed that larval swimming behaviors after sound and light stimulations were significantly different in mutant animals. Thus, we propose that cnr2 is critical for the processing of sensory information in the developing larva.

Cholecalciferol Supplementation Does Not Prevent the Development of Metabolic Syndrome or Enhance the Beneficial Effects of Omega-3 Fatty Acids in Obese Mice

BACKGROUND

Cholecalciferol (D3) may improve inflammation, and thus provide protection from cardiometabolic diseases (CMD), although controversy remains. Omega-3 fatty acids (ω-3FA) may also prevent the development of CMD, but the combined effects of ω-3FA and D3 are not fully understood.

OBJECTIVES

We determined the chronic independent and combined effects of D3 and ω-3FA on body weight, glucose homeostasis, and markers of inflammation in obese mice.

METHODS

We gave 8-week-old male C57BL/6J mice, which had been fed a high-fat, high-sucrose (HF) diet (65.5% kcal fat, 19.8% kcal carbohydrate, and 14% kcal protein) for 12 weeks, either a standard D3 dose (+SD3; 1400 IU D3/kg diet) or a high D3 dose (+HD3; 15,000 IU D3/kg diet). We fed 1 +SD3 group and 1 +HD3 group with 4.36% (w/w) fish oil (+ω-3FA; 44% eicosapentaenoic acid, 25% docosahexaenoic acid), and fed the other 2 groups with corn oil [+omega-6 fatty acids (ω-6FA)]. A fifth group was fed a low-fat (LF; 15.5% kcal) diet. LF and HF+ω-6+SD3 differences were tested by a Student's t-test and HF treatment differences were tested by a 2-way ANOVA.

RESULTS

D3 supplementation in the +HD3 groups did not significantly increase plasma total 25-hydroxyvitamin D and 25-hydroxyvitamin D3 [25(OH)D3] versus the +SD3 groups, but it increased 3-epi-25-hydroxyvitamin D3 levels by 3.4 ng/mL in the HF+ω-6+HD3 group and 4.0 ng/mL in the HF+ω-3+HD3 group, representing 30% and 70%, respectively, of the total 25(OH)D3 increase. Energy expenditure increased in those mice fed diets +ω-3FA, by 3.9% in the HF+ω-3+SD3 group and 7.4% in the HF+ω-3+HD3 group, but it did not translate into lower body weight. The glucose tolerance curves of the HF+ω-3+SD3 and HF+ω-3+HD3 groups were improved by 11% and 17%, respectively, as compared to the respective +ω-6FA groups. D3 supplementation, within the ω-3FA groups, altered the gut microbiota by increasing the abundance of S24-7 and Lachnospiraceae taxa compared to the standard dose, while within the ω-6FA groups, D3 supplementation did not modulate specific taxa.

CONCLUSIONS

Overall, D3 supplementation does not prevent CMD or enhance the beneficial effects of ω-3FA in vitamin D-sufficient obese mice.

Endocannabinoids and the Gut-Brain Control of Food Intake and Obesity

Gut-brain signaling controls food intake and energy homeostasis, and its activity is thought to be dysregulated in obesity. We will explore new studies that suggest the endocannabinoid (eCB) system in the upper gastrointestinal tract plays an important role in controlling gut-brain neurotransmission carried by the vagus nerve and the intake of palatable food and other reinforcers. A focus will be on studies that reveal both indirect and direct interactions between eCB signaling and vagal afferent neurons. These investigations identify (i) an indirect mechanism that controls nutrient-induced release of peptides from the gut epithelium that directly interact with corresponding receptors on vagal afferent neurons, and (ii) a direct mechanism via interactions between eCBs and cannabinoid receptors expressed on vagal afferent neurons. Moreover, the impact of diet-induced obesity on these pathways will be considered.

Targeting the endocannabinoid system in diabesity: Fact or fiction?

'Diabesity' refers to a rising epidemic indicated by the intricate relationship between obesity and diabetes. The global prevalence of these coexisting, insidious diseases increases social and economic health burdens at a rapid pace. Numerous reports delineate the involvement of the underlying endocannabinoid (EC) signaling system through the cannabinoid-1 (CB1) receptor in the regulation of metabolism and adiposity. Conversely, EC inverse agonists can result in severe depression and suicidal thoughts through interactions with CB1/2 receptors in the brain. This review attempts to elucidate a possible mechanism for the amelioration of diabesity. Moreover, we also highlight the available targets of the CB1 receptor, which could pave the way for safe and effective therapy.

Dual inhibition of CB1 receptors and iNOS, as a potential novel approach to the pharmacological management of acute and long COVID-19

COVID‐19 (SARS‐CoV‐2) causes multiple inflammatory complications, resulting not only in severe lung inflammation but also harm to other organs. Although the current focus is on the management of acute COVID‐19, there is growing concern about long‐term effects of COVID‐19 (Long Covid), such as fibroproliferative changes in the lung, heart and kidney. Therefore, the identification of therapeutic targets not only for the management of acute COVID‐19 but also for preventing Long Covid are needed, and would mitigate against long‐lasting health burden and economic costs, in addition to saving lives. COVID‐19 induces pathological changes via multiple pathways, which could be targeted simultaneously for optimal effect. We discuss the potential pathologic function of increased activity of the endocannabinoid/CB₁ receptor system and inducible NO synthase (iNOS). We advocate a polypharmacology approach, wherein a single chemical entity simultaneously interacts with CB₁ receptors and iNOS causing inhibition, as a potential therapeutic strategy for COVID‐19‐related health complications.

Metabolic roles of G protein-coupled receptor signaling in obesity and type 2 diabetes

The incidence of obesity and type 2 diabetes (T2D) has been increasing steadily worldwide. It is estimated that by 2045 more than 800 million people will be suffering from diabetes. Despite the advancements in modern medicine, more effective therapies for treating obesity and T2D are needed. G protein-coupled receptors (GPCRs) have emerged as important drug targets for various chronic diseases, including obesity, T2D, and liver diseases. During the past two decades, many laboratories worldwide focused on understanding the role of GPCR signaling in regulating glucose metabolism and energy homeostasis. The information gained from these studies can guide the development of novel therapeutic agents. In this review, we summarize recent studies providing insights into the role of GPCR signaling in peripheral, metabolically important tissues such as pancreas, liver, skeletal muscle, and adipose tissue, focusing primarily on the use of mutant animal models and human data.

Using (+)-Carvone to access novel derivatives of (+)-ent-Cannabidiol: the first asymmetric syntheses of (+)-ent-CBDP and (+)-ent-CBDV

(-)-Cannabidiol [(-)-CBD] has recently gained prominence as a treatment for neuro-inflammation and other neurodegenerative disorders; interest is also developing in its synthetic enantiomer, (+)-CBD, which has a higher affinity to CB1 / CB2 receptors than the natural stereoisomer. We have developed an inexpensive, stereoselective route to access ent-CBD derivatives using (+)-carvone as a starting material. In addition to (+)-CBD, we report the first syntheses of (+)-cannabidivarin, (+)-cannabidiphorol as well as C-6 / C-8 homologues.

Endocannabinoid-mediated neuromodulation in the main olfactory bulb at the interface of environmental stimuli and central neural processing

The olfactory system has become an important functional gateway to understand and analyze neuromodulation since olfactory dysfunction and deficits have emerged as prodromal and, at other times, as first symptoms of many of neurodegenerative, neuropsychiatric and communication disorders. Considering olfactory dysfunction as outcome of altered, damaged and/or inefficient olfactory processing, in the current review, we analyze how olfactory processing interacts with the endocannabinoid signaling system. In the human body, endocannabinoid synthesis is a natural and on-demand response to a wide range of physiological and environmental stimuli. Our current understanding of the response dynamics of the endocannabinoid system is based in large part on research advances in limbic system areas, such as the hippocampus and the amygdala. Functional interactions of this signaling system with olfactory processing and associated pathways are just emerging but appear to grow rapidly with multidimensional approaches. Recent work analyzing the crystal structure of endocannabinoid receptors bound to their agonists in a signaling complex has opened avenues for developing specific therapeutic drugs that could help with neuroinflammation, neurodegeneration, and alleviation/reduction of pain. We discuss the role of endocannabinoids as signaling molecules in the olfactory system and the relevance of the endocannabinoid system for synaptic plasticity.

Polarity scaffolds signaling in epithelial cell permeability

As an integral part of the innate immune system, the epithelial membrane is exposed to an array of insults that may trigger an immune response. One of the immune system's main functions is to regulate the level of communications between the mucosa and the lumen of various tissues. While it is clear that inhaled or ingested substances, or microorganisms may induce changes that affect the epithelial barrier in various ways, the proteins involved in the signaling cascades and physiological events leading to the regulation and maintenance of the barrier are not always well characterized. We review here some of the signaling components involved in regulating the barrier's paracellular permeability, and their potential effects on the activation of an immune response. While an effective immune response must be launched against pathogenic insults, tolerance must also be maintained for non-pathogenic antigens such as those in the commensal flora or for endogenous metabolites. Along with other members of the innate and adaptive immunity, the endocannabinoid system also plays an instrumental role in maintaining the balance between inflammation and tolerance. We discuss the potential effects of endo- and phytocannabinoids on epithelial permeability and how the dysregulation of this system could be involved in diseases and targeted for therapy.

Molecular Mechanism of Autophagy and Its Regulation by Cannabinoids in Cancer

Simple Summary

This review examines the complex function of autophagy in malignancy and explores its regulation by cannabinoids in different cancers. Autophagy is an important process in the maintenance of cellular homeostasis, through the degradation and recycling of cytoplasmic constituents. The action of autophagy is highly dependent on tumour stage and type and the receptors with which ligands interact. Cannabinoids are growingly being acknowledged for their anticancer activities and are known to stimulate several mechanisms such as apoptosis and autophagy. Better understanding the mechanism of action behind autophagy and its regulation by cannabinoids will allow the development of novel cancer therapeutics.

Abstract

Autophagy is a “self-degradation” process whereby malfunctioned cytoplasmic constituents and protein aggregates are engulfed by a vesicle called the autophagosome, and subsequently degraded by the lysosome. Autophagy plays a crucial role in sustaining protein homeostasis and can be an alternative source of energy under detrimental circumstances. Studies have demonstrated a paradoxical function for autophagy in cancer, displaying both tumour suppressive and tumour promotive roles. In early phases of tumour development autophagy promotes cancer cell death. In later phases, autophagy enables cancer cells to survive and withstand therapy. Cannabinoids, which are derivatives of the Cannabis sativa L. plant, have shown to be associated with autophagy induction in cells. There is an emerging interest in studying the signalling pathways involved in cannabinoid-induced autophagy and their potential application in anticancer therapies. In this review, the molecular mechanisms involved in the autophagy degradation process will be discussed. This review also highlights a role for autophagy in cancer progression, with cannabinoid-induced autophagy presenting a novel strategy for anticancer therapy.

The Intestinal Fatty Acid-Enteroendocrine Interplay, Emerging Roles for Olfactory Signaling and Serotonin Conjugates

Intestinal enteroendocrine cells (EECs) respond to fatty acids from dietary and microbial origin by releasing neurotransmitters and hormones with various paracrine and endocrine functions. Much has become known about the underlying signaling mechanisms, including the involvement of G-protein coupled receptors (GPCRs), like free fatty acids receptors (FFARs). This review focusses on two more recently emerging research lines: the roles of odorant receptors (ORs), and those of fatty acid conjugates in gut. Odorant receptors belong to a large family of GPCRs with functional roles that only lately have shown to reach beyond the nasal-oral cavity. In the intestinal tract, ORs are expressed on serotonin (5-HT) and glucagon-like-peptide-1 (GLP-1) producing enterochromaffin and enteroendocrine L cells, respectively. There, they appear to function as chemosensors of microbiologically produced short-, and branched-chain fatty acids. Another mechanism of fatty acid signaling in the intestine occurs via their conjugates. Among them, conjugates of unsaturated long chain fatty acids and acetate with 5-HT, N-acyl serotonins have recently emerged as mediators with immune-modulatory effects. In this review, novel findings in mechanisms and molecular players involved in intestinal fatty acid biology are highlighted and their potential relevance for EEC-mediated signaling to the pancreas, immune system, and brain is discussed.

Signaling through the type 2 cannabinoid receptor regulates the severity of acute and chronic graft-versus-host disease

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 CB2ReGFP 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 Δ9-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 contributed to disease biology. In vitro, both THC and JWH-133 induced arrestin recruitment and extracellular regulated kinase phosphorylation via CB2R, but THC had no effect on CB2R-mediated inhibition of adenylyl cyclase. This study shows that the CB2R plays a critical role in the regulation of GVHD and suggests that effective therapeutic targeting is dependent upon agonist signaling characteristics and receptor selectivity in conjunction with the composition of pathogenic immune effector cells.

Cannabinoid Receptors in Metabolic Regulation and Diabetes

There is an urgent need for developing effective drugs to combat the obesity and Type 2 diabetes mellitus epidemics. The endocannabinoid system plays a major role in energy homeostasis. It comprises the cannabinoid receptors 1 and 2 (CB₁ and CB₂), endogenous ligands called endocannabinoids and their metabolizing enzymes. Because the CB₁ receptor is overactivated in metabolic alterations, pharmacological blockade of the CB₁ receptor arose as a promising candidate to treat obesity. However, because of the wide distribution of CB₁ receptors in the central nervous system, their negative central effects halted further therapeutic use. Although the CB₂ receptor is mostly peripherally expressed, its role in metabolic homeostasis remains unclear. This review discusses the potential of CB₁ and CB₂ receptors at the peripheral level to be therapeutic targets in metabolic diseases. We focus on the impact of pharmacological intervention and/or silencing on peripheral cannabinoid receptors in organs/tissues relevant for energy homeostasis. Moreover, we provide a perspective on novel therapeutic strategies modulating these receptors. Targeting CB₁ with peripherally restricted antagonists, neutral antagonists, inverse agonists, or monoclonal antibodies could represent successful strategies. CB₂ agonism has shown promising results at preclinical level. Beyond classic antagonism and agonism targeting orthosteric sites, the recently described crystal structures of CB₁ and CB₂ open new possibilities for therapeutic interventions with negative and positive allosteric modulators. The challenge of simultaneously targeting CB₁ and CB₂ might be possible by developing dual-steric ligands. The future will tell whether these promising strategies result in a renaissance of the cannabinoid receptors as therapeutic targets in metabolic diseases.

Human epithelial stem cell survival within their niche requires "tonic" cannabinoid receptor 1-signalling-Lessons from the hair follicle

The endocannabinoid system (ECS) regulates multiple aspects of human epithelial physiology, including inhibition/stimulation of keratinocyte proliferation/apoptosis, respectively. Yet, how the ECS impacts on human adult epithelial stem cell (eSC) functions remains unknown. Scalp hair follicles (HFs) offer a clinically relevant, prototypic model system for studying this directly within the native human stem cell niche. Here, we show in organ-cultured human HFs that, unexpectedly, selective activation of cannabinoid receptor-1 (CB1)-mediated signalling via the MAPK (MEK/Erk 1/2) and Akt pathways significantly increases the number and proliferation of cytokeratin CK15+ or CK19+ human HF bulge eSCs in situ, and enhances CK15 promoter activity in situ. In striking contrast, CB1-stimulation promotes apoptosis in the differentiated progeny of these eSCs (CK6+ HF keratinocytes). Instead, intrafollicular CB1 gene knockdown or CB1 antagonist treatment significantly reduces human HF eSCs numbers and stimulates their apoptosis, while CB1 knockout mice exhibit a reduced bulge eSCs pool in vivo. This identifies "tonic" CB1 signalling as a required survival stimulus for adult human HF eSCs within their niche. This novel concept must be taken into account whenever the human ECS is targeted therapeutically.

The Endocannabinoid System and Invertebrate Neurodevelopment and Regeneration

Cannabis has long been used for its medicinal and psychoactive properties. With the relatively new adoption of formal medicinal cannabis regulations worldwide, the study of cannabinoids, both endogenous and exogenous, has similarly flourished in more recent decades. In particular, research investigating the role of cannabinoids in regeneration and neurodevelopment has yielded promising results in vertebrate models. However, regeneration-competent vertebrates are few, whereas a myriad of invertebrate species have been established as superb models for regeneration. As such, this review aims to provide a comprehensive summary of the endocannabinoid system, with a focus on current advances in the area of endocannabinoid system contributions to invertebrate neurodevelopment and regeneration.

Caloric restriction, physical exercise, and CB1 receptor blockade as an efficient combined strategy for bodyweight control and cardiometabolic status improvement in male rats

Obesity is critically associated with the development of insulin resistance and related cardiovascular and kidney diseases. Several strategies for weight loss have been developed but most of them exhibit a post-intervention rebound effect. Here, we aimed to design combined weight-loss strategies of caloric restriction, physical exercise, and administration of a CB1 receptor blocker to inhibit food intake that also accomplish the objectives of lost-weight maintenance and improvement of cardiovascular and renal function. Diet-induced obesity (DIO) was generated in Sprague Dawley rats for 12 weeks to test the effects of single or combined strategies (i.e. caloric restriction, mixed training protocol, and/or administration of appetite suppressant) on caloric intake, body weight, cardiovascular and renal functionality resulting from a weight-loss intervention period of 3 weeks followed by 6 weeks of weight maintenance. Consumption of a high-fat diet (HFD) caused a significant increase in body weight (5th week of the experimental period) and led to the development of insulin resistance, cardiovascular, and renal alterations. The different interventions tested, resulted in a significant body weight loss and improved glucose metabolism, aerobic capacity, electrocardiographic parameters, vascular expression of adhesion molecules and inflammatory mediators, and renal functionality, reaching values similar to the control normocaloric group or even improving them. Successful maintenance of lost weight was achieved along a 6-week maintenance period in addition to adequate health status. In conclusion, the weight-loss and maintenance intervention strategies tested were efficient at reversing the obesity-related alterations in body weight, glucose metabolism, aerobic capacity, cardiovascular and renal functionality. The beneficial action was very consistent for caloric restriction and physical exercise, whereas administration of a CB1 receptor blocker complemented the effects of the prior interventions in some parameters like body weight or aerobic capacity, and showed specific actions in renal status, increasing glomerular filtration rate and diuresis. Overall, the novelty of our study relies on the easy implementation of combined strategies for effective weight management that resulted in significant health benefits.

Effect of Duyun Compound Green Tea on Gut Microbiota Diversity in High-Fat-Diet-Induced Mice Revealed by Illumina High-Throughput Sequencing

Intake of a high-fat diet (HFD) is closely related to disorders of the intestinal microbiota, which plays a key role in the pathogenesis of obesity. Duyun compound green tea, an ancient Chinese drink, is widely consumed to reduce weight, although the mechanism is not clear. In this study, 50 mice were randomly divided into 5 groups: normal control group (CK), HFD model control group (NK), positive control group with medicine (YK), low-dose compound tea group (DL), and high-dose compound tea group (DH). After 4 weeks of intervention, the feces of mice were taken under sterile conditions and evaluated using Illumina high-throughput sequencing technology. The results showed that the diversity of intestinal microbiota was the highest in the CK group, the lowest in the NK group, and relatively increased in the compound tea treatment group. Second, there were differences in intestinal microbiota in each group, among which the beneficial bacteria in the intestinal tract of the CK group were higher than those in the other groups, while the beneficial bacteria in each compound tea treatment group were more abundant than those in the NK group, in which harmful bacteria in the intestinal tract were found to be the highest. These results suggest that compounds in tea may be able to attenuate imbalances of intestinal microbiota induced by poor diet, acting as a therapeutic agent in obesity or other diseases associated with gut dysbiosis.

Therapeutic Potential of Natural Psychoactive Drugs for Central Nervous System Disorders: A Perspective from Polypharmacology

In the drug development, the formation of highly selective ligands has been unsuccessful in the treatment of central nervous system disorders. Multi-target ligands, from the polypharmacology paradigm, are being proposed as treatments for these complex disorders, since they offer enhanced efficacy and a strong safety profile. Natural products are the best examples of multi-target compounds, so they are of high interest within this paradigm. Additionally, recent research on psychoactive drugs of natural origin, such as ayahuasca and cannabis, has demonstrated the promising therapeutic potential for the treatment of some psychiatric and neurological disorders. In this text, we describe how research on psychoactive drugs can be effectively combined with the polypharmacology paradigm, providing ayahuasca and cannabis research as examples. The advantages and disadvantages are also discussed.

The endocannabinoid system

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.

Interplay of cardiovascular mediators, oxidative stress and inflammation in liver disease and its complications

The liver is a crucial metabolic organ that has a key role in maintaining immune and endocrine homeostasis. Accumulating evidence suggests that chronic liver disease might promote the development of various cardiac disorders (such as arrhythmias and cardiomyopathy) and circulatory complications (including systemic, splanchnic and pulmonary complications), which can eventually culminate in clinical conditions ranging from portal and pulmonary hypertension to pulmonary, cardiac and renal failure, ascites and encephalopathy. Liver diseases can affect cardiovascular function during the early stages of disease progression. The development of cardiovascular diseases in patients with chronic liver failure is associated with increased morbidity and mortality, and cardiovascular complications can in turn affect liver function and liver disease progression. Furthermore, numerous infectious, inflammatory, metabolic and genetic diseases, as well as alcohol abuse can also influence both hepatic and cardiovascular outcomes. In this Review, we highlight how chronic liver diseases and associated cardiovascular effects can influence different organ pathologies. Furthermore, we explore the potential roles of inflammation, oxidative stress, vasoactive mediator imbalance, dysregulated endocannabinoid and autonomic nervous systems and endothelial dysfunction in mediating the complex interplay between the liver and the systemic vasculature that results in the development of the extrahepatic complications of chronic liver disease. The roles of ageing, sex, the gut microbiome and organ transplantation in this complex interplay are also discussed.

Modern approaches to the development of synthetic cannabinoid receptor probes

The endocannabinoid system, which spans the central and peripheral nervous systems and regulates many biologic processes, is an important target for probe discovery and medications development. Whereas the earliest endocannabinoid receptor probes were derivatives of the non-selective phytocannabinoids isolated from Cannabis species, modern drug discovery techniques have expanded the definitions of what constitutes a CB1R or CB2R cannabinoid receptor ligand. This review highlights recent advances in synthetic cannabinoid receptor chemistry and pharmacology. We provide examples of new CB1R- and CB2R-selective probes, and discuss rational approaches to the design of peripherally-restricted agents. We also describe structural classes of positive- and negative allosteric modulators (PAMs and NAMs) of CB1R and CB2R. Finally, we introduce new opportunities for cannabinoid receptor probe development that have emerged in recent years, including biased agonists that may lead to medications lacking adverse effects.

Cannabinoids as Key Regulators of Inflammasome Signaling: A Current Perspective

Inflammasomes are cytoplasmic inflammatory signaling protein complexes that detect microbial materials, sterile inflammatory insults, and certain host-derived elements. Inflammasomes, once activated, promote caspase-1–mediated maturation and secretion of pro-inflammatory cytokines, interleukin (IL)-1β and IL-18, leading to pyroptosis. Current advances in inflammasome research support their involvement in the development of chronic inflammatory disorders in contrast to their role in regulating innate immunity. Cannabis (marijuana) is a natural product obtained from the Cannabis sativa plant, and pharmacologically active ingredients of the plant are referred to as cannabinoids. Cannabinoids and cannabis extracts have recently emerged as promising novel drugs for chronic medical conditions. Growing evidence indicates the potent anti-inflammatory potential of cannabinoids, especially Δ⁹-tetrahydrocannabinol (Δ⁹-THC), cannabidiol (CBD), and synthetic cannabinoids; however, the mechanisms remain unclear. Several attempts have been made to decipher the role of cannabinoids in modulating inflammasome signaling in the etiology of chronic inflammatory diseases. In this review, we discuss recently published evidence on the effect of cannabinoids on inflammasome signaling. We also discuss the contribution of various cannabinoids in human diseases concerning inflammasome regulation. Lastly, in the milieu of coronavirus disease-2019 (COVID-19) pandemic, we confer available evidence linking inflammasome activation to the pathophysiology of COVID-19 suggesting overall, the importance of cannabinoids as possible drugs to target inflammasome activation in or to support the treatment of a variety of human disorders including COVID-19.

Phytocannabinoid Pharmacology: Medicinal Properties of Cannabis sativa Constituents Aside from the "Big Two"

Plant-based therapies date back centuries. Cannabis sativa is one such plant that was used medicinally up until the early part of the 20th century. Although rich in diverse and interesting phytochemicals, cannabis was largely ignored by the modern scientific community due to its designation as a schedule 1 narcotic and restrictions on access for research purposes. There was renewed interest in the early 1990s when the endocannabinoid system (ECS) was discovered, a complex network of signaling pathways responsible for physiological homeostasis. Two key components of the ECS, cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2), were identified as the molecular targets of the phytocannabinoid Δ⁹-tetrahydrocannabinol (Δ⁹-THC). Restrictions on access to cannabis have eased worldwide, leading to a resurgence in interest in the therapeutic potential of cannabis. Much of the focus has been on the two major constituents, Δ⁹-THC and cannabidiol (CBD). Cannabis contains over 140 phytocannabinoids, although only a handful have been tested for pharmacological activity. Many of these minor cannabinoids potently modulate receptors, ionotropic channels, and enzymes associated with the ECS and show therapeutic potential individually or synergistically with other phytocannabinoids. The following review will focus on the pharmacological developments of the next generation of phytocannabinoid therapeutics.

Cannabinoid and Cannabinoid-Related Receptors in the Myenteric Plexus of the Porcine Ileum

An important piece of evidence has shown that molecules acting on cannabinoid receptors influence gastrointestinal motility and induce beneficial effects on gastrointestinal inflammation and visceral pain. The aim of this investigation was to immunohistochemically localize the distribution of canonical cannabinoid receptor type 1 (CB1R) and type 2 (CB2R) and the cannabinoid-related receptors transient potential vanilloid receptor 1 (TRPV1), transient potential ankyrin receptor 1 (TRPA1), and serotonin receptor 5-HT1a (5-HT1aR) in the myenteric plexus (MP) of pig ileum. CB1R, TRPV1, TRPA1, and 5-HT1aR were expressed, with different intensities in the cytoplasm of MP neurons. For each receptor, the proportions of the immunoreactive neurons were evaluated using the anti-HuC/HuD antibody. These receptors were also localized on nerve fibers (CB1R, TRPA1), smooth muscle cells of tunica muscularis (CB1R, 5-HT1aR), and endothelial cells of blood vessels (TRPV1, TRPA1, 5-HT1aR). The nerve varicosities were also found to be immunoreactive for both TRPV1 and 5-HT1aR. No immunoreactivity was documented for CB2R. Cannabinoid and cannabinoid-related receptors herein investigated showed a wide distribution in the enteric neurons and nerve fibers of the pig MP. These results could provide an anatomical basis for additional research, supporting the therapeutic use of cannabinoid receptor agonists in relieving motility disorders in porcine enteropathies.

Regulation of Calcium Oscillations in β-Cells by Co-activated Cannabinoid Receptors

Pharmacological treatment of pancreatic β cells targeting cannabinoid receptors 1 and 2 (CB1 and CB2) has been shown to result in significant effects on insulin release, possibly by modulating intracellular calcium levels ([Ca²⁺]_i). It is unclear how the interplay of CB1 and CB2 affects insulin secretion. Here, we demonstrate by the use of highly specific receptor antagonists and the recently developed photo-releasable endocannabinoid 2-arachidonoylglycerol that both receptors have counteracting effects on cytosolic calcium oscillations. We further show that both receptors are juxtaposed in a way that increases [Ca²⁺]_i oscillations in silent β cells but dampens them in active ones. This study highlights a functional role of CB1 and CB2 acting in concert as a compensator/attenuator switch for regulating β cell excitability.

Phytocannabinoids-A Green Approach toward Non-Alcoholic Fatty Liver Disease Treatment

Non-alcoholic fatty liver disease (NAFLD) is the most frequent chronic liver disease in adults in developed countries, with a global prevalence as high as one billion. The pathogenesis of NAFLD is a multifactorial and multi-step process. Nowadays, a growing body of research suggests the considerable role of the endocannabinoid system (ECS) as a complex cell-signaling system in NAFLD development. Although increased endocannabinoid tone in the liver highly contributes to NAFLD development, the complex effects and impacts of plant-derived cannabinoids in the aspect of NAFLD pathophysiology are yet not fully understood, and effective medications are still in demand. In our review, we present the latest reports describing the role of ECS in NAFLD, focusing primarily on two types of cannabinoid receptors. Moreover, we sum up the recent literature on the clinical use of natural cannabinoids in NAFLD treatment. This review is useful for understanding the importance of ECS in NAFLD development, and it also provides the basis for more extensive clinical phytocannabinoids testing in patients suffering from NAFLD.

Positron Emission Tomography Imaging of the Endocannabinoid System: Opportunities and Challenges in Radiotracer Development

The endocannabinoid system (ECS) is involved in a wide range of biological functions and comprises cannabinoid receptors and enzymes responsible for endocannabinoid synthesis and degradation. Over the past 2 decades, significant advances toward developing drugs and positron emission tomography (PET) tracers targeting different components of the ECS have been made. Herein, we summarized the recent development of PET tracers for imaging cannabinoid receptors 1 (CB1R) and 2 (CB2R) as well as the key enzymes monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), particularly focusing on PET neuroimaging applications. State-of-the-art PET tracers for the ECS will be reviewed including their chemical design, pharmacological properties, radiolabeling, as well as preclinical and human PET imaging. In addition, this review addresses the current challenges for ECS PET biomarker development and highlights the important role of PET ligands to study disease pathophysiology as well as to facilitate drug discovery.

Cannabis sativa L. as a Natural Drug Meeting the Criteria of a Multitarget Approach to Treatment

Cannabis sativa L. turned out to be a valuable source of chemical compounds of various structures, showing pharmacological activity. The most important groups of compounds include phytocannabinoids and terpenes. The pharmacological activity of Cannabis (in epilepsy, sclerosis multiplex (SM), vomiting and nausea, pain, appetite loss, inflammatory bowel diseases (IBDs), Parkinson's disease, Tourette's syndrome, schizophrenia, glaucoma, and coronavirus disease 2019 (COVID-19)), which has been proven so far, results from the affinity of these compounds predominantly for the receptors of the endocannabinoid system (the cannabinoid receptor type 1 (CB1), type two (CB2), and the G protein-coupled receptor 55 (GPR55)) but, also, for peroxisome proliferator-activated receptor (PPAR), glycine receptors, serotonin receptors (5-HT), transient receptor potential channels (TRP), and GPR, opioid receptors. The synergism of action of phytochemicals present in Cannabis sp. raw material is also expressed in their increased bioavailability and penetration through the blood-brain barrier. This review provides an overview of phytochemistry and pharmacology of compounds present in Cannabis extracts in the context of the current knowledge about their synergistic actions and the implications of clinical use in the treatment of selected diseases.

BIONOTE as an Innovative Biosensor for Measuring Endocannabinoid Levels

In this study, a novel approach was developed to quantify endocannabinoids (eCBs), and was based on the liquid biosensor BIONOTE. This device is composed of a probe that can be immersed in a solution, and an electronic interface that can record a current related to the oxy-reductive reactions occurring in the sample. The two most representative members of eCBs have been analysed in vitro by BIONOTE: anandamide (N-arachidonoylethanolamine, AEA) and 2-arachidonoylglycerol (2-AG). Bovine serum albumin was used to functionalize the probe and improve the sensibility of the whole analytical system. We show that BIONOTE is able to detect both AEA and 2-AG at concentrations in the low nanomolar range, and to discriminate between these eCBs and their moieties arachidonic acid, ethanolamine and glycerol. Notably, BIONOTE distinguished these five different molecules, and it was also able to quantify AEA in human plasma. Although this is just a proof-of-concept study, we suggest BIONOTE as a cheap and user-friendly prototype sensor for high throughput quantitation of eCB content in biological matrices, with an apparent diagnostic potential for tomorrow’s medicine.

Cannabinoids in dermatologic surgery

Though known as a medicinal herb for centuries, the recent legalization of cannabinoids across many states has ushered in a new era where cannabinoids have become a popular treatment option among clinicians and patients alike. Cannabinoids have demonstrated efficacy in wound healing, reducing inflammation, ameliorating pain, and have shown potential as an antitumor agent. As a result, cannabinoids have been rapidly woven into the fabric of modern medicine. However, the utility of cannabinoids in dermatologic surgery has not been explored to date. In this article, we review the current literature to discuss the potential impact of cannabinoid use in dermatologic surgery.

Therapeutic potential of cannabinoids in combination cancer therapy

Derivatives of the plant Cannabis sativa have been used for centuries for both medical and recreational purposes, as well as industrial. The first proof of its medicinal use comes from ancient China, although there is evidence of its earlier utilization in Europe and Asia. In the 19th century, European practitioners started to employ cannabis extracts to treat tetanus, convulsions, and mental diseases and, in 1851, cannabis made its appearance in the Pharmacopoeia of the United States as an analgesic, hypnotic and anticonvulsant. It was only in 1937 that the Marijuana Tax Act prohibited the use of this drug in the USA. The general term Cannabis is commonly used by the scientific and scholar community to indicate derivatives of the plant Cannabis sativa. The word cannabinoid is a term describing chemical compounds that are either derivate of Cannabis (phytocannabinoids) or artificial analogues (synthetic) or are produced endogenously by the body (endocannabinoids). A more casual term "marijuana" or "weed", a compound derived from dried Cannabis flower tops and leaves, has progressively superseded the term cannabis when referred to its recreational use. The 2018 World health organisation (WHO) data suggest that nearly 2.5% of the global population (147 million) uses marijuana and some countries, such as Canada and Uruguay, have already legalised it. Due to its controversial history, the medicinal use of cannabinoids has always been a centre of debate. The isolation and characterisation of Δ⁹ tetrahydrocannabinol (THC), the major psychoactive component of cannabis and the detection of two human cannabinoid receptor (CBRs) molecules renewed interest in the medical use of cannabinoids, boosting research and commercial heed in this sector. Some cannabinoid-based drugs have been approved as medications, mainly as antiemetic, antianorexic, anti-seizure remedies and in cancer and multiple sclerosis patients' palliative care. Nevertheless, due to the stigma commonly associated with these compounds, cannabinoids' potential in the treatment of conditions such as cancer is still largely unknown and therefore underestimated.

An Autonomous Cannabinoid System in Islets of Langerhans

While endocannabinoids (ECs) and cannabis were primarily studied for their nervous system effects, it is now clear that ECs are also produced in the periphery where they regulate several physiological processes, including energy storage, glucose and lipid metabolism, insulin secretion and synthesis, and hepatocyte function. Within islet of Langerhans there is an autonomous EC system (ECS). Beta (β)-cells contain all the enzymes necessary for EC synthesis and degradation; ECs are generated in response to cellular depolarization; their paracrine influence on β-cells is mostly through the cannabinoid 1 receptor (CB₁R) that is present on all β-cells; they modulate basal and glucose- and incretin-induced insulin secretion, and β-cell responses to various stressors. Furthermore, there is now accumulating evidence from preclinical studies that the autonomous islet ECS is a key player in obesity-induced inflammation in islets, and β-cell damage and apoptosis from many causes can be mitigated by CB₁R blockers. We will thoroughly review the literature relevant to the effects of ECs and their receptors on β-cells and the other cell types within islets. Therapeutic potential of agents targeting EC/CB₁R and CB₂R is highly relevant because the receptors belong to the druggable G protein-coupled receptor superfamily. Present research in the ECS must be considered preliminary, especially with regards to human islet physiology, and further research is needed in order to translate basic cellular findings into clinical practice and the use of safe, clinically approved CBR modulators with and without glucose lowering combinations presently in therapeutic use for diabetes and obesity needs to be studied.

On the Role of Central Type-1 Cannabinoid Receptor Gene Regulation in Food Intake and Eating Behaviors

Different neuromodulatory systems are involved in long-term energy balance and body weight and, among these, evidence shows that the endocannabinoid system, in particular the activation of type-1 cannabinoid receptor, plays a key role. We here review current literature focusing on the role of the gene encoding type-1 cannabinoid receptors in the CNS and on the modulation of its expression by food intake and specific eating behaviors. We point out the importance to further investigate how environmental cues might have a role in the development of obesity as well as eating disorders through the transcriptional regulation of this gene in order to prevent or to treat these pathologies.

RADIATION DAMAGE OF THE NERVOUS SYSTEM AND ENDOCANABINOIDS

The review analyzes the change of the existing paradigm of high radioresistance of the nervous system according tothe results of the study of neuropsychiatric disorders in in the aftermath of the Chornobyl accident in both earlyand remote post-accident period. The participation of the endocannabinoid system in ensuring homeostasis andpathology formation, potential possibilities of using cannabis drugs, agonists and antagonists of endocannabinoidreceptors for the treatment of early and long-term effects of radiation are considered.

(Endo)Cannabinoids and Gynaecological Cancers

Gynaecological cancers can be primary neoplasms, originating either from the reproductive tract or the products of conception, or secondary neoplasms, representative of metastatic disease. For some of these cancers, the exact causes are unknown; however, it is recognised that the precise aetiopathogeneses for most are multifactorial and include exogenous (such as diet) and endogenous factors (such as genetic predisposition), which mutually interact in a complex manner. One factor that has been recognised to be involved in the pathogenesis and progression of gynaecological cancers is the endocannabinoid system (ECS). The ECS consists of endocannabinoids (bioactive lipids), their receptors, and metabolic enzymes responsible for their synthesis and degradation. In this review, the impact of plant-derived (Cannabis species) cannabinoids and endocannabinoids on gynaecological cancers will be discussed within the context of the complexity of the proteins that bind, transport, and metabolise these compounds in reproductive and other tissues. In particular, the potential of endocannabinoids, their receptors, and metabolic enzymes as biomarkers of specific cancers, such as those of the endometrium, will be addressed. Additionally, the therapeutic potential of targeting selected elements of the ECS as new action points for the development of innovative drugs will be presented.