Isolation and structure of a brain constituent that binds to the cannabinoid receptor

Cannabis and Autoimmunity: Possible Mechanisms of Action

Medical cannabis (MC) describes the usually inhaled or ingested use of a cannabis plant or cannabis extract for medicinal purposes. The action of whole cannabis plants is extremely complex because their large number of active compounds not only bind to a plethora of different receptors but also interact with each other both synergistically and otherwise. Renewed interest in the medicinal properties of cannabis has led to increasing research into the practical uses of cannabis derivatives, and it has been found that the endocannabinoid system (particularly CB2 receptor activation) is a possible target for the treatment of inflammatory and the autoimmune diseases related to immune cell activation. However, in vivo findings still lack, creating difficulties in applying translational cannabinoid research to human immune functions. In this review, we summarized the main mechanisms of action of medical cannabis plant especially regarding the immune system and the endocannabinoid system, looking at preliminary clinical data in three most important autoimmune diseases of three different specialities: rheumatoid arthritis, multiple sclerosis and inflammatory bowel disease.

Molecular basis for ligand modulation of the cannabinoid CB1 receptor

The cannabinoid CB₁ receptor is the most abundant G protein coupled receptor (GPCR) in the central nervous system, which mediates the functional response to endocannabinoids and Cannabis compounds. A variety of ligands for CB₁ receptors have been developed as promising drug candidates for the treatment of neurological disorders. New high-resolution structures of CB₁ receptor in different functional states have significantly improved our molecular understanding of CB₁ ligand interactions, selectivity, receptor activation and allosteric modulation. These advances have paved the way for development of novel ligands for different therapeutic applications. In this review, we describe the structural determinants for modulation of CB₁ receptors by different types of ligands, as well as the differences between CB₁ and its homologous, the CB₂ receptor.

UPLC-MS/MS Method for Analysis of Endocannabinoid and Related Lipid Metabolism in Mouse Mucosal Tissue

The endocannabinoid system is expressed in cells throughout the body and controls a variety of physiological and pathophysiological functions. We describe robust and reproducible UPLC-MS/MS-based methods for analyzing metabolism of the endocannabinoids, 2-arachidonoyl-sn-glycerol and arachidonoyl ethanolamide, and related monoacylglycerols (MAGs) and fatty acid ethanolamides (FAEs), respectively, in mouse mucosal tissues (i.e., intestine and lung). These methods are optimized for analysis of activity of the MAG biosynthetic enzyme, diacylglycerol lipase (DGL), and MAG degradative enzymes, monoacylglycerol lipase (MGL) and alpha/beta hydrolase domain containing-6 (ABHD6). Moreover, we describe a novel UPLC-MS/MS-based method for analyzing activity of the FAE degradative enzyme, fatty acid amide hydrolase (FAAH), that does not require use of radioactive substrates. In addition, we describe in vivo pharmacological methods to inhibit MAG biosynthesis selectively in the mouse small-intestinal epithelium. These methods will be useful for profiling endocannabinoid metabolism in rodent mucosal tissues in health and disease.

Different roles for the acyl chain and the amine leaving group in the substrate selectivity of N-Acylethanolamine acid amidase

N-acylethanolamine acid amidase (NAAA) is an N-terminal nucleophile (Ntn) hydrolase that catalyses the intracellular deactivation of the endogenous analgesic and anti-inflammatory agent palmitoylethanolamide (PEA). NAAA inhibitors counteract this process and exert marked therapeutic effects in animal models of pain, inflammation and neurodegeneration. While it is known that NAAA preferentially hydrolyses saturated fatty acid ethanolamides (FAEs), a detailed profile of the relationship between catalytic efficiency and fatty acid-chain length is still lacking. In this report, we combined enzymatic and molecular modelling approaches to determine the effects of acyl chain and polar head modifications on substrate recognition and hydrolysis by NAAA. The results show that, in both saturated and monounsaturated FAEs, the catalytic efficiency is strictly dependent upon fatty acyl chain length, whereas there is a wider tolerance for modifications of the polar heads. This relationship reflects the relative stability of enzyme-substrate complexes in molecular dynamics simulations.

Cannabinoids Regulate Sensory Processing in Early Olfactory and Visual Neural Circuits

Our sensory systems such as the olfactory and visual systems are the target of neuromodulatory regulation. This neuromodulation starts at the level of sensory receptors and extends into cortical processing. A relatively new group of neuromodulators includes cannabinoids. These form a group of chemical substances that are found in the cannabis plant. Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are the main cannabinoids. THC acts in the brain and nervous system like the chemical substances that our body produces, the endogenous cannabinoids or endocannabinoids, also nicknamed the brain's own cannabis. While the function of the endocannabinoid system is understood fairly well in limbic structures such as the hippocampus and the amygdala, this signaling system is less well understood in the olfactory pathway and the visual system. Here, we describe and compare endocannabinoids as signaling molecules in the early processing centers of the olfactory and visual system, the olfactory bulb, and the retina, and the relevance of the endocannabinoid system for synaptic plasticity.

mGluR5-Mediated eCB Signaling in the Nucleus Accumbens Controls Vulnerability to Depressive-Like Behaviors and Pain After Chronic Social Defeat Stress

Stress contributes to major depressive disorder (MDD) and chronic pain, which affect a significant portion of the global population, but researchers have not clearly determined how these conditions are initiated or amplified by stress. The chronic social defeat stress (CSDS) model is a mouse model of psychosocial stress that exhibits depressive-like behavior and chronic pain. We hypothesized that metabotropic glutamate receptor 5 (mGluR5) expressed in the nucleus accumbens (NAc) normalizes the depressive-like behaviors and pain following CSDS. Here, we show that CSDS induced both pain and social avoidance and that the level of mGluR5 decreased in susceptible mice. Overexpression of mGluR5 in the NAc shell and core prevented the development of depressive-like behaviors and pain in susceptible mice, respectively. Conversely, depression-like behaviors and pain were exacerbated in mice with mGluR5 knockdown in the NAc shell and core, respectively, compared to control mice subjected to 3 days of social defeat stress. Furthermore, (RS)-2-chloro-5-hydroxyphenylglycine (CHPG), an mGluR5 agonist, reversed the reduction in the level of the endocannabinoid (eCB) 2-arachidonoylglycerol (2-AG) in the NAc of susceptible mice, an effect that was blocked by 3-((2-methyl-1, 3-thiazol-4-yl) ethynyl) pyridine hydrochloride (MTEP), an mGluR5 antagonist. In addition, the injection of CHPG into the NAc shell and core normalized depressive-like behaviors and pain, respectively, and these effects were inhibited by AM251, a cannabinoid type 1 receptor (CB1R) antagonist. Based on these results, mGluR5-mediated eCB production in the NAc relieves stress-induced depressive-like behaviors and pain.

Function and therapeutic potential of N-acyl amino acids

N-acyl amino acids (NAAs) are amphiphilic molecules, with different potential fatty acid and head group moieties. NAAs are the largest family of anandamide congener lipids discovered to date. In recent years, several NAAs have been identified as potential ligands, engaging novel binding sites and mechanisms for modulation of membrane proteins such as G-protein coupled receptors (GPRs), nuclear receptors, ion channels, and transporters. NAAs play a key role in a variety of physiological functions as lipid signaling molecules. Understanding the structure, function roles, and pharmacological potential of these NAAs is still in its infancy, and the biochemical roles are also mostly unknown. This review will provide a summary of the literature on NAAs and emphasize their therapeutic potential.

Cannabinoids, the endocannabinoid system, and pain: a review of preclinical studies

ABSTRACT

This narrative review represents an output from the International Association for the Study of Pain's global task force on the use of cannabis, cannabinoids, and cannabis-based medicines for pain management, informed by our companion systematic review and meta-analysis of preclinical studies in this area. Our aims in this review are (1) to describe the value of studying cannabinoids and endogenous cannabinoid (endocannabinoid) system modulators in preclinical/animal models of pain; (2) to discuss both pain-related efficacy and additional pain-relevant effects (adverse and beneficial) of cannabinoids and endocannabinoid system modulators as they pertain to animal models of pathological or injury-related persistent pain; and (3) to identify important directions for future research. In service of these goals, this review (1) provides an overview of the endocannabinoid system and the pharmacology of cannabinoids and endocannabinoid system modulators, with specific relevance to animal models of pathological or injury-related persistent pain; (2) describes pharmacokinetics of cannabinoids in rodents and humans; and (3) highlights differences and discrepancies between preclinical and clinical studies in this area. Preclinical (rodent) models have advanced our understanding of the underlying sites and mechanisms of action of cannabinoids and the endocannabinoid system in suppressing nociceptive signaling and behaviors. We conclude that substantial evidence from animal models supports the contention that cannabinoids and endocannabinoid system modulators hold considerable promise for analgesic drug development, although the challenge of translating this knowledge into clinically useful medicines is not to be underestimated.

The endocannabinoid system - current implications for drug development

In this review, the state of the art for compounds affecting the endocannabinoid (eCB) system is described with a focus on the treatment of pain. Amongst directly acting CB receptor ligands, clinical experience with ∆⁹ -tetrahydracannabinol and medical cannabis in chronic non-cancer pain indicates that there are differences between the benefits perceived by patients and the at best modest effect seen in meta-analyses of randomized controlled trials. The reason for this difference is not known but may involve differences in the type of patients that are recruited, the study conditions that are chosen and the degree to which biases such as reporting bias are operative. Other directly acting CB receptor ligands such as biased agonists and allosteric receptor modulators have not yet reached the clinic. Amongst indirectly acting compounds targeting the enzymes responsible for the synthesis and catabolism of the eCBs anandamide and 2-arachidonoylglycerol, fatty acid amide hydrolase (FAAH) inhibitors have been investigated clinically but were per se not useful for the treatment of pain, although they may be useful for the treatment of post-traumatic stress disorder and cannabis use disorder. Dual-acting compounds targeting this enzyme and other targets such as cyclooxygenase-2 or transient potential vanilloid receptor 1 may be a way forward for the treatment of pain.

Cannabinoids in Neurology - Position paper from Scientific Departments from Brazilian Academy of Neurology

Cannabinoids comprehend endocannabinoids, phytocannabinoids, and synthetic cannabinoids, with actions both in the central and peripherical nervous systems. A considerable amount of publications have been made in recent years, although cannabis has been known for over a thousand years. Scientific Departments from the Brazilian Academy of Neurology described evidence for medical use in their areas. Literature is constantly changing, and possible new evidence can emerge in the next days or months. Prescription of these substances must be discussed with patients and their families, with knowledge about adverse events and their efficacy.

Prediction of essential binding domains for the endocannabinoid N-arachidonoylethanolamine (AEA) in the brain cannabinoid CB1 receptor

Δ9-tetrahydrocannabinol (Δ9-THC), the main active ingredient of Cannabis sativa (marijuana), interacts with the human brain cannabinoid (CB1) receptor and mimics pharmacological effects of endocannabinoids (eCBs) like N-arachidonylethanolamide (AEA). Due to its flexible nature of AEA structure with more than 15 rotatable bonds, establishing its binding mode to the CB1 receptor is elusive. The aim of the present study was to explore possible binding conformations of AEA within the binding pocket of the CB1 receptor confirmed in the recently available X-ray crystal structures of the CB1 receptor and predict essential AEA binding domains. We performed long time molecular dynamics (MD) simulations of plausible AEA docking poses until its receptor binding interactions became optimally established. Our simulation results revealed that AEA favors to bind to the hydrophobic channel (HC) of the CB1 receptor, suggesting that HC holds essential significance in AEA binding to the CB1 receptor. Our results also suggest that the Helix 2 (H2)/H3 region of the CB1 receptor is an AEA binding subsite privileged over the H7 region.

Tonic Endocannabinoid Signaling Gates Synaptic Plasticity in Dorsal Raphe Nucleus Serotonin Neurons Through Peroxisome Proliferator-Activated Receptors

Endocannabinoids (eCBs), which include 2-arachidonoylglycerol (2-AG) and anandamide (AEA) are lipid signaling molecules involved in the regulation of an array of behavioral and physiological functions. Released by postsynaptic neurons, eCBs mediate both phasic and tonic signaling at central synapses. While the roles of phasic eCB signaling in modulating synaptic functions and plasticity are well characterized, very little is known regarding the physiological roles and mechanisms regulating tonic eCB signaling at central synapses. In this study, we show that both 2-AG and AEA are constitutively released in the dorsal raphe nucleus (DRN), where they exert tonic control of glutamatergic synaptic transmission onto serotonin (5-HT) neurons. The magnitude of this tonic eCB signaling is tightly regulated by the overall activity of neuronal network. Thus, short term in vitro neuronal silencing or blockade of excitatory synaptic transmission abolishes tonic eCB signaling in the DRn. Importantly, in addition to controlling basal synaptic transmission, this study reveals that tonic 2-AG, but not AEA signaling, modulates synaptic plasticity. Indeed, short-term increase in tonic 2-AG signaling impairs spike-timing dependent potentiation (tLTP) of glutamate synapses. This tonic 2-AG-mediated homeostatic control of DRN glutamate synapses is not signaled by canonical cannabinoid receptors, but by intracellular peroxisome proliferator-activated receptor gamma (PPARγ). Further examination reveals that 2-AG mediated activation of PPARγ blocks tLTP by inhibiting nitric oxide (NO), soluble guanylate cyclase, and protein kinase G (NO/sGC/PKG) signaling pathway. Collectively, these results unravel novel mechanisms by which tonic 2-AG signaling integrates network activities and controls the synaptic plasticity in the brain.

Communication and social interaction in the cannabinoid-type 1 receptor null mouse: Implications for autism spectrum disorder

Clinical and preclinical findings have suggested a role of the endocannabinoid system (ECS) in the etiopathology of autism spectrum disorder (ASD). Previous mouse studies have investigated the role of ECS in several behavioral domains; however, none of them has performed an extensive assessment of social and communication behaviors, that is, the main core features of ASD. This study employed a mouse line lacking the primary endocannabinoid receptor (CB1r) and characterized ultrasonic communication and social interaction in CB1^-/- , CB1^+/- , and CB1^+/+ males and females. Quantitative and qualitative alterations in ultrasonic vocalizations (USVs) were observed in CB1 null mice both during early development (i.e., between postnatal days 4 and 10), and at adulthood (i.e., at 3 months of age). Adult mutants also showed marked deficits in social interest in the three-chamber test and social investigation in the direct social interaction test. These behavioral alterations were mostly observed in both sexes and appeared more marked in CB1^-/- than CB1^+/- mutant mice. Importantly, the adult USV alterations could not be attributed to differences in anxiety or sensorimotor abilities, as assessed by the elevated plus maze and auditory startle tests. Our findings demonstrate the role of CB1r in social communication and behavior, supporting the use of the CB1 full knockout mouse in preclinical research on these ASD-relevant core domains. LAY SUMMARY: The endocannabinoid system (ECS) is important for brain development and neural function and is therefore likely to be involved in neurodevelopmental disorders such as Autism Spectrum Disorder (ASD). Here we investigated changes in social behavior and communication, which are core features of ASD, in male and female mice lacking the chief receptor of this system. Our results show that loss of this receptor results in several changes in social behavior and communication both during early development and in adulthood, thus supporting the role of the ECS in these ASD-core behavioral domains.

Cannabinoid Receptors in Myocardial Injury: A Brother Born to Rival

Cannabinoid receptors typically include type 1 (CB1) and type 2 (CB2), and they have attracted extensive attention in the central nervous system (CNS) and immune system. Due to more in-depth studies in recent years, it has been found that the typical CB1 and CB2 receptors confer functional importance far beyond the CNS and immune system. In particular, many works have reported the critical involvement of the CB1 and CB2 receptors in myocardial injuries. Both pharmacological and genetic approaches have been used for studying CB1 and CB2 functions in these studies, revealing that the brother receptors have many basic differences and sometimes antagonistic functions in a variety of myocardial injuries, despite some sequence or location identity they share. Herein, we introduce the general differences of CB1 and CB2 cannabinoid receptors, and summarize the functional rivalries between the two brother receptors in the setting of myocardial injuries. We point out the importance of individual receptor-based modulation, instead of dual receptor modulators, when treating myocardial injuries.

Pros and Cons of the Cannabinoid System in Cancer: Focus on Hematological Malignancies

The endocannabinoid system (ECS) is a composite cell-signaling system that allows endogenous cannabinoid ligands to control cell functions through the interaction with cannabinoid receptors. Modifications of the ECS might contribute to the pathogenesis of different diseases, including cancers. However, the use of these compounds as antitumor agents remains debatable. Pre-clinical experimental studies have shown that cannabinoids (CBs) might be effective for the treatment of hematological malignancies, such as leukemia and lymphoma. Specifically, CBs may activate programmed cell death mechanisms, thus blocking cancer cell growth, and may modulate both autophagy and angiogenesis. Therefore, CBs may have significant anti-tumor effects in hematologic diseases and may synergistically act with chemotherapeutic agents, possibly also reducing chemoresistance. Moreover, targeting ECS might be considered as a novel approach for the management of graft versus host disease, thus reducing some symptoms such as anorexia, cachexia, fatigue, anxiety, depression, and neuropathic pain. The aim of the present review is to collect the state of the art of CBs effects on hematological tumors, thus focusing on the essential topics that might be useful before moving into the clinical practice.

Zerumbone Ameliorates Neuropathic Pain Symptoms via Cannabinoid and PPAR Receptors Using In Vivo and In Silico Models

Neuropathic pain is a chronic pain condition persisting past the presence of any noxious stimulus or inflammation. Zerumbone, of the Zingiber zerumbet ginger plant, has exhibited anti-allodynic and antihyperalgesic effects in a neuropathic pain animal model, amongst other pharmacological properties. This study was conducted to further elucidate the mechanisms underlying zerumbone's antineuropathic actions. Research on therapeutic agents involving cannabinoid (CB) and peroxisome proliferator-activated receptors (PPARs) is rising. These receptor systems have shown importance in causing a synergistic effect in suppressing nociceptive processing. Behavioural responses were assessed using the von Frey filament test (mechanical allodynia) and Hargreaves plantar test (thermal hyperalgesia), in chronic constriction injury (CCI) neuropathic pain mice. Antagonists SR141716 (CB1 receptor), SR144528 (CB2 receptor), GW6471 (PPARα receptor) and GW9662 (PPARγ receptor) were pre-administered before the zerumbone treatment. Our findings indicated the involvement of CB1, PPARα and PPARγ in zerumbone's action against mechanical allodynia, whereas only CB1 and PPARα were involved against thermal hyperalgesia. Molecular docking studies also suggest that zerumbone has a comparable and favourable binding affinity against the respective agonist on the CB and PPAR receptors studied. This finding will contribute to advance our knowledge on zerumbone and its significance in treating neuropathic pain.

The endocannabinoid system as a therapeutic target for schizophrenia: Failures and potentials

Owing to its psychotropic effects, Cannabis has been stigmatized by its recreational use leading to a dramatic decline in the experimentations about its medical use in the twentieth century. The medical properties of the plant - known since ancient times - have received increased attention over recent years; yet, the research on its potential application in the field of psychiatry is still nascent. In this connection, the non-psychotropic cannabidiol (CBD) has emerged as a phytocannabinoid compound with promising antipsychotic effects. In addition, advances in our understanding of the endocannabinoid system, along with accumulating evidence implicating this system in the pathophysiology of schizophrenia, have stimulated research by the pharmaceutical industry to explore whether alteration of this system can be of medical benefit. This review examines the current state of evidence regarding the clinical potential of cannabinoid-based drugs as a treatment for schizophrenia, while discussing various limitations with the therapeutic approaches considered so far. In the second part, the author highlights the most promising strategies, as well as the most interesting directions one could follow, in the emerging field of cannabinoid therapies for schizophrenia.

Global Trends in Cannabis and Cannabidiol Research from the Year 1940 to 2019

Legalization of Cannabis in countries, like Canada, and global demand for non-hallucinating chemical components, such as Cannabidiols (CBD), have stimulated the increased interest from academics, industry, and regulatory agencies. Subsequent research publications in scientific journals in this field are expected to grow rapidly. However, there have been few research reviews that have quantified patterns in research publications concerning cannabis, nor a literature-based perspective on the historical development, current status, and future direction of cannabis research. Here, a bibliometric analysis is performed to address this gap in the scientific literature. A total of 1167 relevant articles (Supplementary file 1) were screened and analyzed using three software tools: HistCite, CiteSpace, and Bibliometric Online Analysis Platform. The performances of relevant countries, institutions, authors, and journals were presented, and the evolutionary trends of different categories were revealed. The historical development of cannabis and CBD research can be clearly divided into three stages, which focus on the chemistry, pharmacology, and molecular biology aspects of Cannabis sativa in general and then a focus on CBD related publications. A timeline was drawn to highlight the major trends in the literature, including scientific discoveries. In the end, several suggestions for future research directions in this field are provided.

Persistent Cannabis Abuse and Risk for Hospitalization for Acute Pancreatitis: A Cross-Sectional Study in United States Hospitals

Objectives

To explore the independent association between cannabis abuse and subsequent hospitalizations for acute pancreatitis (AP) and delineate the demographic differences among AP in patients with and without persistent cannabis abuse.

Methods

We conducted a retrospective cross-sectional study using the nationwide inpatient sample and included 50,444,133 patients (age 18-50 years) with a primary discharge diagnosis for medical illnesses and further grouped by presence of AP (N = 666,248). We used the logistic regression model to measure the odds ratio (OR) of the association between cannabis abuse and hospitalization for AP and adjusted it for demographic confounders and comorbid risk factors.

Results

Cannabis abuse significantly increases the odds for AP-related hospitalization (OR 2.12, P <0.001). When the regression model was controlled for potential risk factors (gall stones, cystic fibrosis, hypertriglyceridemia, hypercalcemia, hyperparathyroidism, abdominal surgeries, tobacco abuse, and alcohol abuse), cannabis abuse did not increase the odds for AP-related hospitalization (OR 0.72, P <0.001) due to the significant effect caused by gallstones (OR 30.98, P <0.001) and alcohol abuse (OR 12.69, P <0.001). AP inpatients with cannabis abuse were younger compared to non-cannabis abusers (mean age, 35.7 vs. 37.9 years), and majorly male (70.9% vs. 53.8%). AP was considerably more prevalent in whites (60.6%), followed by blacks (18.3%) and Hispanics (15.2%).

Conclusion

Cannabis abuse increased the unadjusted odds for AP-related hospitalization by two times, but after controlling for potential risk factors the adjusted odds of association significantly reduced. Cannabis-induced AP can be treated if a problematic recreational cannabis use pattern is discontinued at an earlier stage. Therefore, awareness campaigns and early supportive therapy among cannabis abusers might help diagnose and treat the comorbidity and improve the quality of life. 

Roles of Endocannabinoids and Endocannabinoid-like Molecules in Energy Homeostasis and Metabolic Regulation: A Nutritional Perspective

The endocannabinoid system is involved in signal transduction in mammals. It comprises principally G protein-coupled cannabinoid receptors and their endogenous agonists, called endocannabinoids, as well as the enzymes and transporters responsible for the metabolism of endocannabinoids. Two arachidonic acid-containing lipid molecules, arachidonoylethanolamide (anandamide) and 2-arachidonoylglycerol, function as endocannabinoids. N-acylethanolamines and monoacylglycerols, in which the arachidonic acid chain is replaced with a saturated or monounsaturated fatty acid, are not directly involved in the endocannabinoid system but exhibit agonistic activities for other receptors. These endocannabinoid-like molecules include palmitoylethanolamide, oleoylethanolamide (OEA), and 2-oleoylglycerol. Endocannabinoids stimulate feeding behavior and the anabolism of lipids and glucose, while OEA suppresses appetite. Both central and peripheral systems are included in these nutritional and metabolic contexts. Therefore, they have potential in the treatment and prevention of obesity. We outline the structure, metabolism, and biological activities of endocannabinoids and related molecules, and focus on their involvement in energy homeostasis and metabolic regulation. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Cannabinoid Modulation of Dopamine Release During Motivation, Periodic Reinforcement, Exploratory Behavior, Habit Formation, and Attention

Motivational and attentional processes energize action sequences to facilitate evolutionary competition and promote behavioral fitness. Decades of neuropharmacology, electrophysiology and electrochemistry research indicate that the mesocorticolimbic DA pathway modulates both motivation and attention. More recently, it was realized that mesocorticolimbic DA function is tightly regulated by the brain's endocannabinoid system and greatly influenced by exogenous cannabinoids-which have been harnessed by humanity for medicinal, ritualistic, and recreational uses for 12,000 years. Exogenous cannabinoids, like the primary psychoactive component of cannabis, delta-9-tetrahydrocannabinol, produce their effects by acting at binding sites for naturally occurring endocannabinoids. The brain's endocannabinoid system consists of two G-protein coupled receptors, endogenous lipid ligands for these receptor targets, and several synthetic and metabolic enzymes involved in their production and degradation. Emerging evidence indicates that the endocannabinoid 2-arachidonoylglycerol is necessary to observe concurrent increases in DA release and motivated behavior. And the historical pharmacology literature indicates a role for cannabinoid signaling in both motivational and attentional processes. While both types of behaviors have been scrutinized under manipulation by either DA or cannabinoid agents, there is considerably less insight into prospective interactions between these two important signaling systems. This review attempts to summate the relevance of cannabinoid modulation of DA release during operant tasks designed to investigate either motivational or attentional control of behavior. We first describe how cannabinoids influence DA release and goal-directed action under a variety of reinforcement contingencies. Then we consider the role that endocannabinoids might play in switching an animal's motivation from a goal-directed action to the search for an alternative outcome, in addition to the formation of long-term habits. Finally, dissociable features of attentional behavior using both the 5-choice serial reaction time task and the attentional set-shifting task are discussed along with their distinct influences by DA and cannabinoids. We end with discussing potential targets for further research regarding DA-cannabinoid interactions within key substrates involved in motivation and attention.

Cannabinoid-induced changes in the immune system: The role of microRNAs

Naturally occurring cannabinoids have been used by humans for their medicinal benefits for over several millennia. While the use of cannabinoids has been strictly regulated in the past century, easing of state regulations has been associated with an increase in use of cannabinoids in the United States. The potential therapeutic applications of cannabinoids have been explored and the anti-inflammatory effect of cannabis-derived cannabinoids has been well-documented. The pharmacological effects of cannabinoids are governed by the modulation of cannabinoid receptors, CB₁ and CB₂, expressed in the central and peripheral tissues. Moreover, growing scientific evidence suggests that the cannabinoid-mediated changes in the immune system involves change in expression of microRNAs (miRNAs). MiRNAs are short non-coding, single-stranded RNA which have the ability to affect post-translational regulation of gene expression. Studies over the past decade have investigated the changes in expression of miRNAs following treatment of various components of the immune system with different chemical modulators of the cannabinoid receptors. Such studies have highlighted the key role played by various miRNAs in driving the observed immunomodulatory effects of cannabinoids. The aim of this review article, therefore, is to summarize the role of miRNAs behind the observed effects of cannabinoids on the overall immune system, rather than focusing on a single disease state.

Targeting the endocannabinoid system for management of HIV-associated neuropathic pain: A systematic review

Human immunodeficiency virus (HIV) infection and antiretroviral therapy can independently induce HIV-associated neuropathic pain (HIV-NP). There is a dearth of drugs or therapeutic modalities that can alleviate HIV-NP. Smoked cannabis has been reported to improve pain measures in patients with neuropathic pain. Cannabis, phytocannabinoids, and the endocannabinoids such N-arachidonoylethanolamine (anandamide; AEA) and 2-arachidonoylglycerol (2-AG), produce some of their effects via cannabinoid receptors (CBRs). Endocannabinoids are degraded by various enzymes such as fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase. We searched PubMed, Google Scholar, clinicaltrials.gov and clinicaltrialsregister.eu using various key words and their combinations for published papers that studied HIV-NP and cannabis, cannabinoids, or endocannabinoids up to 27th December 2020. All original research articles that evaluated the efficacy of molecules that modulate the endocannabinoid system (ECS) for the prevention and/or treatment of pain in HIV-NP animal models and patients with HIV-NP were included. The PubMed search produced a total of 117 articles, whereas the Google Scholar search produced a total of 9467 articles. Amongst the 13 articles that fulfilled the inclusion criteria 11 articles were found in both searches whereas 2 articles were found in Google Scholar only. The clinicaltrials.gov and clinicaltrialsregister.eu searches produced five registered trials of which three were completed and with results. Ten preclinical studies found that the endocannabinoids (2-AG and AEA), synthetic mixed CB1R/CB2R agonist WIN 55,212-2, a CB2R-selective phytocannabinoid β-caryophyllene, synthetic CB2R-selective agonists (AM1710, JWH015, JWH133 and Gp1a, but not HU308); FAAH inhibitors (palmitoylallylamide, URB597 and PF-3845) and a drug combination of indomethacin plus minocycline, which produces its effects in a CBR-dependent manner, either prevented the development of and/or attenuated established HIV-NP. Two clinical trials demonstrated greater efficacy of smoked cannabis over placebo in alleviating HIV-NP, whereas another clinical trial demonstrated that cannabidivarin, a cannabinoid that does not activate CBRs, did not reduce HIV-NP. The available preclinical results suggest that targeting the ECS for prevention and treatment of HIV-NP is a plausible therapeutic option. Clinical evidence shows that smoked cannabis alleviates HIV-NP. Further research is needed to find out if non-psychoactive drugs that target the ECS and are delivered by other routes than smoking could be useful as treatment options for HIV-NP.

Unconventional high-value products from microalgae: A review

Microalgae have gained significant importance in biotechnology development, providing valuable goods and services in multiple applications. Although there is a rising market for most of these applications, the incorporation and introduction of microalgae into new venues will extend in the near future. These advances are due to the vast biodiversity of microalgal species, recent genetic engineering tools, and culture techniques. There are three main possible approaches for novel algal compounds from: (1) recently isolated yet less known microalgae; (2) selectively stressed conditions; and (3) enzymatically adjusted compounds from conventional molecules. All these approaches can be combined in a specific manner. This review discusses the opportunities, potential and limitations of introducing novel microalgae-based products, and how the recent technologies can be deployed to make these products financially viable. To give an outlook to the future, an analysis of the developments and predicted future market that further enlarge the promise of cultivating microalgae for commercial purposes are considered.

Gut-inhabiting Clostridia build human GPCR ligands by conjugating neurotransmitters with diet- and human-derived fatty acids

Human physiology is regulated by endogenous signalling compounds, including fatty acid amides (FAAs), chemical mimics of which are made by bacteria. The molecules produced by human-associated microbes are difficult to identify because they may only be made in a local niche or they require a substrate sourced from the host, diet or other microbes. We identified a set of uncharacterized gene clusters in metagenomics data from the human gut microbiome. These clusters were discovered to make FAAs by fusing exogenous fatty acids with amines. Using an in vitro assay, we tested their ability to incorporate 25 fatty acids and 53 amines known to be present in the human gut, from which the production of six FAAs was deduced (oleoyl dopamine, oleoyl tyramine, lauroyl tryptamine, oleoyl aminovaleric acid, α-linolenoyl phenylethylamine and caproyl tryptamine). These molecules were screened against panels of human G-protein-coupled receptors to deduce their putative human targets. Lauroyl tryptamine is found to be an antagonist to the immunomodulatory receptor EBI2 against its native oxysterol ligand (0.98 μM half-maximal inhibitory concentration), is produced in culture by Eubacterium rectale and is present in human faecal samples. FAAs produced by Clostridia may serve as a mechanism to modulate their host by mimicking human signalling molecules.

Endocannabinoids in immune regulation and immunopathologies

Endocannabinoids are key bioactive components of the endocannabinoid system, and the profound influence of endocannabinoids on the modulation of the immune system is being increasingly appreciated. The knowledge of endocannabinoid-immune cell crosstalk will pave the way to therapeutic implications of modulators of this pathway in autoimmune and chronic inflammatory disorders. Endocannabinoids seem to exert both anti-inflammatory and pro-inflammatory effects in specific contexts, based on specific receptor engagement and the downstream signalling pathways involved. In this review, we summarized the biosynthesis, signalling and degradation of two well-studied endocannabinoids-anandamide and 2-arachidonylglycerol in immune cells. Then, we discussed the effects of these two endocannabinoids on the functioning of major innate and adaptive immune cells, along with the choice of receptors employed in such interactions. Finally, we outline our current knowledge on the involvement of anandamide and 2-arachidonylglycerol in context of inflammation, allergies, autoimmunity and metabolic disorders.

Persistent proteomic changes in glutamatergic and GABAergic signaling in the amygdala of adolescent rats exposed to chlorpyrifos as juveniles

Chlorpyrifos (CPF) remains one of the most widely used organophosphorus insecticides (OPs) despite the concerns about its developmental neurotoxicity. Developmental exposure to CPF has long-lasting negative impacts, including abnormal emotional behaviors. These negative impacts are observed at exposure levels do not cause inhibition of acetylcholinesterase, the canonical target of OPs. Exposure to CPF at these levels inhibits the endocannabinoid metabolizing enzyme fatty acid amide hydrolase (FAAH) but it is not clear what the persistent effects of this inhibition are. To investigate this, male rat pups were exposed orally to either corn oil, 0.75 mg/kg CPF, or 0.02 mg/kg PF-04457845 (PF; a specific inhibitor of FAAH) daily from postnatal day 10 (PND10) - PND16. This dosage of CPF does not inhibit brain cholinesterase activity but inhibits FAAH activity. On PND38 (adolescence), the protein expression in the amygdala was determined using a label-free shotgun proteomic approach. The analysis of control vs CPF and control vs PF led to the identification of 44 and 142 differentially regulated proteins, respectively. Gene ontology enrichment analysis revealed that most of the proteins with altered expression in both CPF and PF treatment groups were localized in the synapse-related regions, such as presynaptic membrane, postsynaptic density, and synaptic vesicle. The different biological processes affected by both treatment groups included persistent synaptic potentiation, glutamate receptor signaling, protein phosphorylation, and chemical synaptic transmission. These results also indicated disturbances in the balance between glutamatergic (↓ Glutamate AMPA receptor 2, ↓ Excitatory amino acid transporter 2, and ↑ vesicular glutamate transporter 2) and GABAergic signaling (↑ GABA transporter 3 and ↑ glutamate decarboxylase 2). This imbalance could play a role in the abnormal emotional behavior that we have previously reported. These results suggest that there is a similar pattern of expression between CPF and PF, and both these chemicals can persistently alter emotional behavior as a consequence of inhibition of FAAH.

Synthesis, Characterization, and DFT Studies of N-(3,5-Bis(trifluoromethyl)benzyl)stearamide

The novel N-(3,5-bis(trifluoromethyl)benzyl)stearamide 3 was prepared in moderate yield by a solventless direct amidation reaction of stearic acid 1 with 3,5-bis(trifluoromethyl)benzylamine 2 at 140 °C for 24 h under metal- and catalyst-free conditions. This practical method was conducted in air without any special treatment or activation. The fatty acid amide 3 was fully characterized by IR, UV–Vis, 1D and 2D NMR spectroscopy, mass spectrometry, and elemental analysis. Moreover, molecular electrostatic potential studies, determination of quantum descriptors, fundamental vibrational frequencies, and intensity of vibrational bands were computed by density functional theory (DFT) using the B3LYP method with 6-311+G(d,p) basis set in gas phase. Simulation of the infrared spectrum using the results of these calculations led to good agreement with the observed spectral patterns.

Modulation of Endocannabinoids by Caloric Restriction Is Conserved in Mice but Is Not Required for Protection from Acute Kidney Injury

Acute kidney injury (AKI) is a frequent and critical complication in the clinical setting. In rodents, AKI can be effectively prevented through caloric restriction (CR), which has also been shown to increase lifespan in many species. In Caenorhabditis elegans (C. elegans), longevity studies revealed that a marked CR-induced reduction of endocannabinoids may be a key mechanism. Thus, we hypothesized that regulation of endocannabinoids, particularly arachidonoyl ethanolamide (AEA), might also play a role in CR-mediated protection from renal ischemia-reperfusion injury (IRI) in mammals including humans. In male C57Bl6J mice, CR significantly reduced renal IRI and led to a significant decrease of AEA. Supplementation of AEA to near-normal serum concentrations by repetitive intraperitoneal administration in CR mice, however, did not abrogate the protective effect of CR. We also analyzed serum samples taken before and after CR from patients of three different pilot trials of dietary interventions. In contrast to mice and C. elegans, we detected an increase of AEA. We conclude that endocannabinoid levels in mice are modulated by CR, but CR-mediated renal protection does not depend on this effect. Moreover, our results indicate that modulation of endocannabinoids by CR in humans may differ fundamentally from the effects in animal models.

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.

Cannabis and Cannabinoids in Reproduction and Fertility: Where We Stand

Although cannabis use is increasing in general population, their prevalence among young adults is remarkably high. In recent years, their medical use gained a renewed interest. However, it can underline the reputation of cannabis being a harmless drug. Between cannabinoids, uniquely found on the cannabis plant, Δ⁹-tetrahydrocannabinol (THC) is the well-studied compound. It is responsible for the psychoactive effects via central cannabinoid receptors. Nevertheless, cannabinoids interact with other chemical signalling systems such as the hypothalamic-pituitary-gonadal axis. THC indirectly decreases gonadotropin-releasing hormone (GnRH) secretion by the hypothalamus. The consequences are diverse, and several key hormones are affected. THC disturbs important reproductive events like folliculogenesis, ovulation and sperm maturation and function. Although generally accepted that cannabinoid consumption impacts male and female fertility, prevailing evidence remains largely on pre-clinical studies. Here, we introduce cannabinoids and the endocannabinoid system, and we review the most prominent clinical evidence about cannabis consumption in reproductive potential and teratogenicity.

The Endogenous Cannabinoid and the Nitricoxidergic Systems Differently Influence Heat and Cold Stress-Induced Analgesia

Stress-induced analgesia (SIA) is a well-known phenomenon, in which mechanisms of development opioid and non-opioid components take part. The endogenous cannabinoid system (ECS) takes part in the non-opioid pathways and modulates nociception. Nitric oxide (NO) is also proverbial to interfere with pain perception. The present study was performed to investigate the effects from interaction between the ECS and NO after heat (heat stress) or cold (cold stress) exposure. Male Wistar rats subjected to one hour of heat or cold stress were injected with different combinations of cannabinoid receptor type 1 (CB1) agonist anandamide (AEA) or antagonist (AM251) along with NO-donor, NO-precursor or inhibitor of the NO-synthase (NOS). Nociception was evaluated using Paw pressure (Randall-Selitto) test. The results showed that AEA-administration immediately after the end of stress let to a tendency to increase cold-SIA, but decreased heat-SIA. AEA along with NO-donor increased both cold- and heat-SIA but to a different degree. AM251 and NOS-inhibitor decreased SIA. Our experiments confirmed that the endogenous cannabinoid and the nitricoxidergic systems interact between them in the modulation of SIA. The ECS exerts a more prominent influence on cold rather than heat SIA. Differences in modulation probably depend on the type of stress, due to the different participation of ECS in the mechanisms of SIA development.

Impairment of Synaptic Plasticity by Cannabis, Δ9-THC, and Synthetic Cannabinoids

The ability of neurons to dynamically and flexibly encode synaptic inputs via short- and long-term plasticity is critical to an organism's ability to learn and adapt to the environment. Whereas synaptic plasticity may be encoded by pre- or postsynaptic mechanisms, current evidence suggests that optimization of learning requires both forms of plasticity. Endogenous cannabinoids (eCBs) play critical roles in modulating synaptic transmission via activation of cannabinoid CB1 receptors (CB1Rs) in many central nervous system (CNS) regions, and the eCB system has been implicated, either directly or indirectly, in several forms of synaptic plasticity. Because of this, perturbations within the eCB signaling system can lead to impairments in a variety of learned behaviors. One agent of altered eCB signaling is exposure to "exogenous cannabinoids" such as the primary psychoactive constituent of cannabis, Δ⁹-THC, or illicit synthetic cannabinoids that in many cases have higher potency and efficacy than Δ⁹-THC. Thus, by targeting the eCB system, these agonists can produce widespread impairment of synaptic plasticity by disrupting ongoing eCB function. Here, we review studies in which Δ⁹-THC and synthetic cannabinoids impair synaptic plasticity in a variety of neuronal circuits and examine evidence that this contributes to their well-documented ability to disrupt cognition and behavior.

Acute and Severe Acute Pancreatitis and the Effect of Cannabis in States Before and After Legalization Compared With States Without Legalized Cannabis

OBJECTIVES

Cannabis legalization has increased its use. The incidence of acute pancreatitis (AP) and severe acute pancreatitis (SAP) has also increased. In this study, data on pancreatitis were obtained from 2 states before and after cannabis legalization and compared with 2 states without legalized cannabis.

METHODS

Data were extracted from State Inpatient Databases from the states of Colorado and Washington before recreational cannabis legalization (2011) and after legalization (2015). Arizona and Florida were used as the nonlegalized cannabis states. Multivariable logistic regression models were fit for AP and SAP to determine a trend difference between legalized and nonlegalized cannabis states.

RESULTS

Cannabis use, AP, and SAP increased in all states. The increase in AP and SAP was not significantly different between the states that legalized cannabis use and those that did not. Legalized cannabis states had lower charges for AP and SAP and shorter length of hospitalizations.

CONCLUSIONS

The trend of AP and SAP increased during the study period, but this was not correlated to cannabis use. Cannabis users had lower hospitalization costs and hospital stay. The effects of other confounders such as cannabis dose and delivery methods, alcohol, tobacco, and others need to be studied further as use increases.

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®.

Heritability and family-based GWAS analyses of the N-acyl ethanolamine and ceramide plasma lipidome

Signalling lipids of the N-acyl ethanolamine (NAE) and ceramide (CER) classes have emerged as potential biomarkers of cardiovascular disease (CVD). We sought to establish the heritability of plasma NAEs (including the endocannabinoid anandamide) and CERs, to identify common DNA variants influencing the circulating concentrations of the heritable lipids, and assess causality of these lipids in CVD using 2-sample Mendelian randomization (2SMR). Nine NAEs and 16 CERs were analyzed in plasma samples from 999 members of 196 British Caucasian families, using targeted ultra-performance liquid chromatography with tandem mass spectrometry. All lipids were significantly heritable (h2 = 36-62%). A missense variant (rs324420) in the gene encoding the enzyme fatty acid amide hydrolase (FAAH), which degrades NAEs, associated at genome-wide association study (GWAS) significance (P < 5 × 10-8) with four NAEs (DHEA, PEA, LEA and VEA). For CERs, rs680379 in the SPTLC3 gene, which encodes a subunit of the rate-limiting enzyme in CER biosynthesis, associated with a range of species (e.g. CER[N(24)S(19)]; P = 4.82 × 10-27). We observed three novel associations between SNPs at the CD83, SGPP1 and DEGS1 loci, and plasma CER traits (P < 5 × 10-8). 2SMR in the CARDIoGRAMplusC4D cohorts (60 801 cases; 123 504 controls) and in the DIAGRAM cohort (26 488 cases; 83 964 controls), using the genetic instruments from our family-based GWAS, did not reveal association between genetically determined differences in CER levels and CVD or diabetes. Two of the novel GWAS loci, SGPP1 and DEGS1, suggested a casual association between CERs and a range of haematological phenotypes, through 2SMR in the UK Biobank, INTERVAL and UKBiLEVE cohorts (n = 110 000-350 000).

Untapped endocannabinoid pharmacological targets: Pipe dream or pipeline?

It has been established that the endogenous cannabinoid (endocannabinoid) system plays key modulatory roles in a wide variety of pathological conditions. The endocannabinoid system comprises both cannabinoid receptors, their endogenous ligands including 2-arachidonoylglycerol (2-AG), N-arachidonylethanolamine (anandamide, AEA), and enzymes that regulate the synthesis and degradation of endogenous ligands which include diacylglycerol lipase alpha (DAGL-α), diacylglycerol lipase beta (DAGL-β), fatty acid amide hydrolase (FAAH), monoacylglycerol lipase (MAGL), α/β hydrolase domain 6 (ABHD6). As the endocannabinoid system exerts considerable involvement in the regulation of homeostasis and disease, much effort has been made towards understanding endocannabinoid-related mechanisms of action at cellular, physiological, and pathological levels as well as harnessing the various components of the endocannabinoid system to produce novel therapeutics. However, drug discovery efforts within the cannabinoid field have been slower than anticipated to reach satisfactory clinical endpoints and raises an important question into the validity of developing novel ligands that therapeutically target the endocannabinoid system. To answer this, we will first examine evidence that supports the existence of an endocannabinoid system role within inflammatory diseases, neurodegeneration, pain, substance use disorders, mood disorders, as well as metabolic diseases. Next, this review will discuss recent clinical studies, within the last 5 years, of cannabinoid compounds in context to these diseases. We will also address some of the challenges and considerations within the cannabinoid field that may be important in the advancement of therapeutics into the clinic.

Endocannabinoid system and its modulation of brain, gut, joint and skin inflammation

The discovery of endogenous cannabinoid receptors CB₁ and CB₂ and their endogenous ligands has generated interest in the endocannabinoid system and has contributed to the understanding of the role of the endocannabinoid system. Its role in the normal physiology of the body and its implication in pathological states such as cardiovascular diseases, neoplasm, depression and pain have been subjects of scientific interest. In this review the authors focus on the endogenous cannabinoids, and the critical role of cannabinoid receptor signaling in neurodegeneration and other inflammatory responses such as gut, joint and skin inflammation. This review also discusses the potential of endocannabinoid pathways as drug targets in the amelioration of some inflammatory conditions. Though the exact role of the endocannabinoid system is not fully understood, the evidence found much clearly points to a great potential in exploiting both its central and peripheral pathways in disease management. Cannabinoid therapy has proven promising in several preclinical and clinical trials.

The Endocannabinoid Anandamide Attenuates Acute Respiratory Distress Syndrome by Downregulating miRNA that Target Inflammatory Pathways

Acute respiratory distress syndrome (ARDS) is defined as a type of respiratory failure that is caused by a variety of insults such as pneumonia, sepsis, trauma and certain viral infections. In this study, we investigated the effect of an endocannabinoid, anandamide (AEA), on ARDS induced in the mouse by Staphylococcus Enterotoxin B (SEB). Administration of a single intranasal dose of SEB in mice and treated with exogenous AEA at a dose of 40 mg/kg body weight led to the amelioration of ARDS in mice. Clinically, plethysmography results indicated that there was an improvement in lung function after AEA treatment accompanied by a decrease of inflammatory cell infiltrate. There was also a significant decrease in pro-inflammatory cytokines IL-2, TNF-α, and IFN-γ, and immune cells including CD4⁺ T cells, CD8⁺ T cells, Vβ8⁺ T cells, and NK⁺ T cells in the lungs. Concurrently, an increase in anti-inflammatory phenotypes such as CD11b + Gr1+ Myeloid-derived Suppressor Cells (MDSCs), CD4 + FOXP3 + Tregs, and CD4⁺IL10 + cells was observed in the lungs. Microarray data showed that AEA treatment in ARDS mice significantly altered numerous miRNA including downregulation of miRNA-23a-3p, which caused an upregulation of arginase (ARG1), which encodes for arginase, a marker for MDSCs, as well as TGF-β2, which induces Tregs. AEA also caused down-regulation of miRNA-34a-5p which led to induction of FoxP3, a master regulator of Tregs. Transfection of T cells using miRNA-23a-3p or miRNA-34a-5p mimics and inhibitors confirmed that these miRNAs targeted ARG1, TGFβ2 and FoxP3. In conclusion, the data obtained from this study suggests that endocannabinoids such as AEA can attenuate ARDS induced by SEB by suppressing inflammation through down-regulation of key miRNA that regulate immunosuppressive pathways involving the induction of MDSCs and Tregs.

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.

Anandamide alters the membrane properties, halts the cell division and prevents drug efflux in multidrug resistant Staphylococcus aureus

Antibiotic resistance is a serious public health problem throughout the world. Overcoming methicillin and multidrug-resistant Staphylococcus aureus (MRSA/MDRSA) infections has become a challenge and there is an urgent need for new therapeutic approaches. We have previously demonstrated that the endocannabinoid Anandamide (AEA) can sensitize MRSA to antibiotics. Here we have studied the mechanism of action using a MDRSA clinical isolate that are sensitized by AEA to methicillin and norfloxacin. We found that AEA treatment halts the growth of both antibiotic-sensitive and antibiotic-resistant S. aureus. The AEA-treated bacteria become elongated and the membranes become ruffled with many protrusions. AEA treatment also leads to an increase in the percentage of bacteria having a complete septum, suggesting that the cell division is halted at this stage. The latter is supported by cell cycle analysis that shows an accumulation of bacteria in the G2/M phase after AEA treatment. We further observed that AEA causes a dose-dependent membrane depolarization that is partly relieved upon time. Nile red staining of the bacterial membranes indicates that AEA alters the membrane structures. Importantly, 4'-6-diamidino-2-phenylindole (DAPI) accumulation assay and ethidium bromide efflux (EtBr) assay unveiled that AEA leads to a dose-dependent drug accumulation by inhibiting drug efflux. In conclusion, our study demonstrates that AEA interferes with cell division, alters the membrane properties of MDRSA, and leads to increased intracellular drug retention, which can contribute to the sensitization of MDRSA to antibiotics.

Protein Dynamics Influence the Enzymatic Activity of Phospholipase A/Acyltransferases 3 and 4

Phospholipase A/acyltransferase 3 (PLAAT3) and PLAAT4 are enzymes involved in the synthesis of bioactive lipids. Despite sequential and structural similarities, the two enzymes differ in activity and specificity. The relation between the activity and dynamics of the N-terminal domains of PLAAT3 and PLAAT4 was studied. PLAAT3 has a much higher melting temperature and exhibits less nanosecond and millisecond dynamics in the active site, in particular in loop L2(B6), as shown by NMR spectroscopy and molecular dynamics calculations. Swapping the L2(B6) loops between the two PLAAT enzymes results in strongly increased phospholipase activity in PLAAT3 but no reduction in PLAAT4 activity, indicating that this loop contributes to the low activity of PLAAT3. The results show that, despite structural similarity, protein dynamics differ substantially between the PLAAT variants, which can help to explain the activity and specificity differences.

Activation of TRPV1 by Capsaicin or Heat Drives Changes in 2-Acyl Glycerols and N-Acyl Ethanolamines in a Time, Dose, and Temperature Dependent Manner

Endocannabinoids (eCBs) and transient receptor potential (TRP) channels are associated with thermoregulation; however, there are many gaps in the understanding of how these signaling systems work together in responding to changes in temperature. TRPV1, a calcium-permeable ion channel, is activated by capsaicin, elevated temperature, the eCB Anandamide, and over 15 additional endogenous lipids. There is also evidence for signaling crosstalk between TRPV1 and the eCB receptor, CB₁. We recently found that activation of TRPV1-HEK cells by capsaicin increases the production of the eCB, 2-arachidonoyl glycerol (2-AG), suggesting a molecular link between these receptors. Here, we tested the hypothesis that TRPV1 activation by capsaicin drives regulation of a wider-range of lipid signaling molecules and is time and dose-dependent. We also tested the hypothesis that changes in temperature that drive changes in calcium mobilization in TRPV1-HEK will likewise drive similar changes in lipid signaling molecule regulation. Lipid analysis was conducted by partial purification of methanolic extracts on C18 solid phase extraction columns followed by HPLC/MS/MS. Capsaicin increased the release of 2-acyl glycerols (2-AG, 2-linoleoyl glycerol, 2-oleoyl glycerol), in a concentration- and time-dependent manner, whereas levels of N-acyl ethanolamines (NAEs), including Anandamide, were significantly decreased. Analogous changes in 2-acyl glycerols and NAEs were measured upon ramping the temperature from 37 to 45°C. In contrast, opposite effects were measured when analyzing lipids after they were maintained at 27°C and then quickly ramped to 37°C, wherein 2-acyl glycerol levels decreased and NAEs increased. These results provide further evidence that the eCB system and TRPV1 have integrated signaling functions that are associated with the molecular response to temperature variation.

Cannabinoid Receptor Type-2 in B Cells Is Associated with Tumor Immunity in Melanoma

Simple Summary

In this study we investigated the role of cannabinoid receptor 2 (CB2R) on immune cells in melanoma and found significantly improved overall survival in patients with high intra-tumoral CB2R gene expression. In human melanoma, CB2R is predominantly expressed in B cells, as shown using a previously published single-cell RNA sequencing (scRNA-seq) dataset and by performing RNAscope. In a murine melanoma model, tumor growth was enhanced in CB2R-deficient mice. In-depth analysis of tumor-infiltrating lymphocytes using scRNA-seq showed less differentiated B cells in CB2R-deficient tumors, favoring the induction of regulatory T cells (T_reg) and an immunosuppressive tumor microenvironment. Taken together, these data indicate a central role of CB2R on B cells in regulating tumor immunity. These results contribute to the understanding of the role of CB2R in tumor immunity and facilitate the development of new CB2R-targeted anti-cancer drugs.

Abstract

Agents targeting the endocannabinoid system (ECS) have gained attention as potential cancer treatments. Given recent evidence that cannabinoid receptor 2 (CB2R) regulates lymphocyte development and inflammation, we performed studies on CB2R in the immune response against melanoma. Analysis of The Cancer Genome Atlas (TCGA) data revealed a strong positive correlation between CB2R expression and survival, as well as B cell infiltration in human melanoma. In a murine melanoma model, CB2R expression reduced the growth of melanoma as well as the B cell frequencies in the tumor microenvironment (TME), compared to CB2R-deficient mice. In depth analysis of tumor-infiltrating B cells using single-cell RNA sequencing suggested a less differentiated phenotype in tumors from Cb2r^−/− mice. Thus, in this study, we demonstrate for the first time a protective, B cell-mediated role of CB2R in melanoma. This gained insight might assist in the development of novel, CB2R-targeted cancer therapies.

Para-Aminobenzohydrazide Derivatives as Fatty Acid Amide Hydrolase Inhibitors: Design, Synthesis and Biological Evaluation

The endocannabinoid system plays an important neuromodulatory role in the periphery and central nervous system, which can regulate several physiological processes. The inhibition of enzymatic activities responsible for hydrolysis anandamide and other endogenous fatty acid amides, enhances cannabinoid receptors activity indirectly that may prove to be useful drugs for the treatment of range of ailments including pain, anxiety, and other central nervous system disorders. In this study, we designed, synthesized, and evaluated novel fatty acid amide hydrolase (FAAH) inhibitors based on 4-aminobenzohydrazide derivatives. Most of the synthesized compounds exhibited a proper affinity for the catalytic triad of FAAH in docking studies and had a considerable in-vitro FAAH inhibitory activity in comparison with JZL-195, a potent inhibitor of FAAH. Compound 2-(2-(4-(2-carboxybenzamido) benzoyl) hydrazine-1-carbonyl) benzoic acid, 12, was found to be the most potent inhibitor with IC₅₀ value of 1.62 nM targeting FAAH enzyme.

Increased Excitatory Synaptic Transmission Associated with Adult Seizure Vulnerability Induced by Early-Life Inflammation in Mice

Early-life inflammatory stress increases seizure susceptibility later in life. However, possible sex- and age-specific differences and the associated mechanisms are largely unknown. C57BL/6 mice were bred in house, and female and male pups were injected with lipopolysaccharide (LPS; 100 μg/kg, i.p.) or vehicle control (saline solution) at postnatal day 14 (P14). Seizure threshold was assessed in response to pentylenetetrazol (1% solution, i.v.) in adolescence (∼P40) and adulthood (∼P60). We found that adult, but not adolescent, mice treated with LPS displayed ∼34% lower seizure threshold compared with controls. Females and males showed similar increased seizure susceptibility, suggesting that altered brain excitability was age dependent, but not sex dependent. Whole-cell recordings revealed no differences in excitatory synaptic activity onto CA1 pyramidal neurons from control or neonatally inflamed adolescent mice of either sex. However, adult mice of both sexes previously exposed to LPS displayed spontaneous EPSC frequency approximately twice that of controls, but amplitude was unchanged. Although these changes were not associated with alterations in dendritic spines or in the NMDA/AMPA receptor ratio, they were linked to an increased glutamate release probability from Schaffer collateral, but not temporoammonic pathway. This glutamate increase was associated with reduced activity of presynaptic GABA_B receptors and was independent of the endocannabinoid-mediated suppression of excitation. Our new findings demonstrate that early-life inflammation leads to long-term increased hippocampal excitability in adult female and male mice associated with changes in glutamatergic synaptic transmission. These alterations may contribute to enhanced vulnerability of the brain to subsequent pathologic challenges such as epileptic seizures.SIGNIFICANCE STATEMENT Adult physiology has been shown to be affected by early-life inflammation. Our data reveal that early-life inflammation increases excitatory synaptic transmission onto hippocampal CA1 pyramidal neurons in an age-dependent manner through disrupted presynaptic GABA_B receptor activity on Schaffer collaterals. This hyperexcitability was seen only in adult, and not in adolescent, animals of either sex. The data suggest a maturation process, independent of sex, in the priming action of early-life inflammation and highlight the importance of studying mature brains to reveal cellular changes associated with early-life interventions.

Cerebrovascular Complications Associated with Marijuana Use

PURPOSE OF REVIEW

In the last few years, the attitude toward marijuana in many parts of the world has shifted from illicit to legalized for medical use and to decriminalized. In parallel, there has been a gradual increase in the consumption of this product in the general population, particularly among adolescents and young adults. Marijuana is generally perceived as a harmless drug. However, data obtained in observational studies and preclinical models have established associations between cannabis use and cardiovascular events. In addition, there is emerging evidence linking marijuana use to cerebrovascular complications. Here we provide a critical review of the literature with special emphasis on the association of cannabinoids with stroke and the possible pathogenic mechanisms involved.

RECENT FINDINGS

Ischemic and hemorrhagic stroke have been described in association with cannabis use, particularly in young individuals. Cerebral infarction remains the most commonly reported stroke subtype seen in marijuana users. Several pathogenic mechanisms have been proposed to explain this association, including multifocal intracranial stenosis, reversible cerebral vasoconstriction syndrome, and coexisting vascular risk factors. Cannabis use is increasingly recognized in young individuals presenting with acute stroke. Our understanding of the pathogenic mechanisms associated with cannabis use and stroke is limited but rapidly evolving. Healthcare providers should educate patients about the potential cardiovascular and cerebrovascular complications related to marijuana or cannabinoids use.

Delayed on- and off-retinal responses of cones pathways in regular cannabis users: An On-Off flash electroretinogram case-control study

The retina is considered a useful area for investigating synaptic transmission abnormalities in neuropsychiatric disorders, including as a result of using cannabis, the most widely consumed illicit substance in the developed world. The impact of regular cannabis use on retinal function has already been evaluated, using pattern and flash electroretinogram (ERG) to demonstrate a delay in ganglion and bipolar cell response. Using multifocal ERG, it was showed that the delay to be preferentially located in the central retina. ERG tests do not separately examine the impact of cannabis on the On and Off pathways. The purpose of this study is to assess On and Off pathway function using On-Off ERG. We conducted an On-Off ERG test in 42 regular cannabis users and 26 healthy controls. The protocol was compliant with the International Society for Clinical Electrophysiology of Vision (ISCEV) standards. Amplitude and peak time were measured for the a-, b- and d-waves. Results in the regular cannabis users showed a significant increase in the latencies of both the b- and the d-wave (p = 0.020, p = 0.022, respectively, Mann-Whitney U test), with no change in the wave amplitudes. A-wave peak time and amplitude were unchanged. These findings are reflective of an effect of regular cannabis use on the On and Off pathways and are consistent with previous findings which also identified increases in retinal neuron response times. We confirm here that regular cannabis use impacts the post-receptoral cones pathway at the level of bipolar cells, affecting the On and Off pathways.

The effects of inhibition of fatty acid amide hydrolase (FAAH) by JNJ-42165279 in social anxiety disorder: a double-blind, randomized, placebo-controlled proof-of-concept study

JNJ-42165279 is a selective inhibitor of fatty acid amide hydrolase (FAAH), the enzyme responsible for the degradation of fatty acid amides (FAA) including anandamide (AEA), palmitoylethanolamide (PEA), and N-oleoylethanolamide (OEA). We assessed the efficacy, safety, tolerability, pharmacokinetics, and pharmacodynamics of treatment with JNJ-42165279 in subjects with social anxiety disorder (SAD). This was a multicenter, double-blind, placebo-controlled study randomizing subjects to 12 weeks of treatment with either JNJ-42165279 (25 mg daily) or placebo (PBO). The primary endpoint was the change in the Liebowitz Social Anxiety Scale (LSAS) total score from baseline to end of study. Secondary endpoints included the Hamilton Anxiety Scale (HAM-A), Hamilton Depression Rating Scale (HDRS₁₇), and the Clinical Global Impression-Improvement (CGI-I). Samples were collected for plasma concentration of AEA, PEA, OEA, and JNJ-42165279. A total of 149 subjects were enrolled with a mean baseline LSAS total score of 102.6 (SD 16.84). The mean change from baseline (SD) in LSAS total score at week 12 was numerically greater for JNJ-42165279: -29.4 (27.47) compared to PBO: -22.4 (23.57) but not significant. The percentage of subjects with ≥30% improvement from baseline in the LSAS total score was significantly higher for JNJ-42165279 (42.4%) compared to PBO (23.6%) (p value = 0.04). The percentage of subjects with a CGI-I score of much or very much improved was also significantly higher for JNJ-42165279 (44.1%) than for PBO (23.6%) (p value = 0.02). The drug was well tolerated. JNJ-42165279 appears to elicit an anxiolytic effect in subjects with SAD although trough concentrations with 25 mg once daily appeared to be insufficient to completely inhibit FAAH activity which may have led to suboptimal efficacy. ClinicalTrials.gov Identifier: NCT02432703.