Targeting the CB2 receptor for immune modulation

Emerging roles of cannabinoid receptor CB2 receptor in the central nervous system: therapeutic target for CNS disorders

RATIONALE

The endocannabinoid system (ECS) belongs to the G protein-coupled receptor family of cell membranes and is associated with neuropsychiatric conditions, and neurodegenerative diseases. Cannabinoid 2 receptors (CB2) are expressed in the central nervous system (CNS) on microglia and subgroups of neurons and are involved in various behavioural processes via immunological and neural regulation.

OBJECTIVE

The objective of this paper is to summarize and explore the impact of CB2 receptors on neuronal modulation, their involvement in various neurological disorders, and their influence on mood, behavior, and cognitive function.

RESULTS

The activation of CB2 appears to protect the brain and its functions from damage under neuroinflammatory actions, making it an attractive target in a variety of neurological conditions such as Parkinson's disease (PD), multiple sclerosis (MS), Alzheimer's disease (AD), and Huntington's disease (HD). During inflammation, there is an overexpression of CB2 receptors, and CB2 agonists show a strong anti-inflammatory effect. These results have sparked interest in the CB2 receptors as a potential target for neurodegenerative and neuroinflammatory disease treatment.

CONCLUSION

In conclusion, CB2 receptors signalling shows promise for developing targeted interventions that could positively affect both immune and neuronal functions, ultimately influencing behavioral outcomes in both health and disease.

The two synthetic cannabinoid compounds 4'-F-CBD and HU-910 efficiently restrain inflammatory responses of brain microglia and astrocytes

To study the anti-inflammatory potential of the two synthetic cannabinoids 4'-F-CBD and HU-910, we used post-natal brain cultures of mouse microglial cells and astrocytes activated by reference inflammogens. We found that 4'-F-CBD and HU-910 efficiently curtailed the release of TNF-α, IL-6, and IL-1β in microglia and astrocytes activated by the bacterial Toll-Like Receptor (TLR)4 ligand LPS. Upon LPS challenge, 4'-F-CBD and HU-910 also prevented the activation of phenotypic activation markers specific to microglia and astrocytes, that is, Iba-1 and GFAP, respectively. In microglial cells, the two test compounds also efficiently restrained LPS-stimulated release of glutamate, a non-cytokine inflammation marker for these cells. The immunosuppressive effects of the two cannabinoid compounds were concentration-dependent and observable between 1 and 10 μM. These effects were not dependent on cannabinoid or cannabinoid-like receptors. Both 4'-F-CBD and HU-910 were also capable of restraining the inflammogenic activity of Pam3CSK4, a lipopeptide that activates TLR2, and of BzATP, a prototypic agonist of P2X7 purinergic receptors, suggesting that these two cannabinoids could exert immunosuppressive effects against a variety of inflammatory stimuli. Using LPS-stimulated microglia and astrocytes, we established that the immunosuppressive action of 4'-F-CBD and HU-910 resulted from the inhibition of ROS produced by NADPH oxidase and subsequent repression of NF-κB-dependent signaling events. Our results suggest that 4'-F-CBD and HU-910 may have therapeutic utility in pathological conditions where neuroinflammatory processes are prominent.

Implications of the endocannabinoid system and the therapeutic action of cannabinoids in autism spectrum disorder: A literature review

Autism spectrum disorder (ASD) is a neurodevelopmental disorder, onset in early childhood and associated with cognitive, social, behavioral, and sensory impairments. The pathophysiology is still unclear, and it is believed that genetic and environmental factors are fully capable of influencing ASD, especially cell signaling and microglial functions. Furthermore, the endocannabinoid system (ECS) participates in the modulation of various brain processes and is also involved in the pathophysiological mechanisms of this condition. Due to the health and quality of life impacts of autism for the patient and his/her family and the lack of effective medications, the literature has elucidated the possibility that Cannabis phytocannabinoids act favorably on ASD symptoms, probably through the modulation of neurotransmitters, in addition to endogenous ligands derived from arachidonic acid, metabolizing enzymes and even transporters of the membrane. These findings support the notion that there are links between key features of ASD and ECS due to the favorable actions of cannabidiol (CBD) and other cannabinoids on symptoms related to behavioral and cognitive disorders, as well as deficits in communication and social interaction, hyperactivity, anxiety and sleep disorders. Thus, phytocannabinoids emerge as therapeutic alternatives for ASD.

Molecular Insights into Epigenetics and Cannabinoid Receptors

The actions of cannabis are mediated by G protein-coupled receptors that are part of an endogenous cannabinoid system (ECS). ECS consists of the naturally occurring ligands N-arachidonylethanolamine (anandamide) and 2-arachidonoylglycerol (2-AG), their biosynthetic and degradative enzymes, and the CB1 and CB2 cannabinoid receptors. Epigenetics are heritable changes that affect gene expression without changing the DNA sequence, transducing external stimuli in stable alterations of the DNA or chromatin structure. Cannabinoid receptors are crucial candidates for exploring their functions through epigenetic approaches due to their significant roles in health and diseases. Epigenetic changes usually promote alterations in the expression of genes and proteins that can be evaluated by various transcriptomic and proteomic analyses. Despite the exponential growth of new evidence on the critical functions of cannabinoid receptors, much is still unknown regarding the contribution of various genetic and epigenetic factors that regulate cannabinoid receptor gene expression. Recent studies have identified several immediate and long-lasting epigenetic changes, such as DNA methylation, DNA-associated histone proteins, and RNA regulatory networks, in cannabinoid receptor function. Thus, they can offer solutions to many cellular, molecular, and behavioral impairments found after modulation of cannabinoid receptor activities. In this review, we discuss the significant research advances in different epigenetic factors contributing to the regulation of cannabinoid receptors and their functions under both physiological and pathological conditions. Increasing our understanding of the epigenetics of cannabinoid receptors will significantly advance our knowledge and could lead to the identification of novel therapeutic targets and innovative treatment strategies for diseases associated with altered cannabinoid receptor functions.

Elucidation of partial activation of cannabinoid receptor type 2 and identification of potential partial agonists: Molecular dynamics simulation and structure-based virtual screening

Cannabinoid receptor type 2 (CB2R) is a member of the class A G protein-coupled receptor (GPCRs) family and a component of the endocannabinoid system that is modulated by the psychoactive chemical from Cannabis sativa, partial agonist Δ⁹-tetrahydrocannabinol (Δ⁹-THC). Selective activation of CB2R allows for the treatment of inflammatory and immune-related conditions without the psychotropic effects of CB1R. While CB2R-selective agonists are available, CB2R partial agonists are scarce. Hence, the pharmacological difference between CB2R full agonists and partial agonists remains to be deciphered, prompting the search for novel partial agonists. Here, using an induced-fit docking approach, we built a partial agonist Δ⁹-THC bound CB2R system from the inactive CB2R structure (PDB ID: 5ZTY) and performed microsecond molecular dynamics (MD) simulations. The simulations reveal an upward shift of the "toggle switch" W6.48⁽²⁵⁸⁾ and minor outward movement of the transmembrane helix 6 (TM6). Dynamic network model identifies a possible communication path between the ligand and the toggle switch" W6.48⁽²⁵⁸⁾. Furthermore, to identify potential CB2R partial agonists, we conducted structure-based virtual screening of ZINC15 "Druglike" library containing 17,900742 compounds against 3 conformations derived from MD simulation of CB2R complexed with partial agonist Δ⁹-THC using Glide virtual screening protocol comprising various filters with increasing accuracy. Nine diverse compounds predicted to have high MM-GBSA binding energy scores and good ADMET properties (including high gastrointestinal absorption and low toxicity) are proposed as potential CB2R partial agonists.

Modulation of Endocannabinoid System Components in Depression: Pre-Clinical and Clinical Evidence

Depression is characterized by continuous low mood and loss of interest or pleasure in enjoyable activities. First-line medications for mood disorders mostly target the monoaminergic system; however, many patients do not find relief with these medications, and those who do suffer from negative side effects and a discouragingly low rate of remission. Studies suggest that the endocannabinoid system (ECS) may be involved in the etiology of depression and that targeting the ECS has the potential to alleviate depression. ECS components (such as receptors, endocannabinoid ligands, and degrading enzymes) are key neuromodulators in motivation and cognition as well as in the regulation of stress and emotions. Studies in depressed patients and in animal models for depression have reported deficits in ECS components, which is motivating researchers to identify potential diagnostic and therapeutic biomarkers within the ECS. By understanding the effects of cannabinoids on ECS components in depression, we enhance our understanding of which brain targets they hit, what biological processes they alter, and eventually how to use this information to design better therapeutic options. In this article, we discuss the literature on the effects of cannabinoids on ECS components of specific depression-like behaviors and phenotypes in rodents and then describe the findings in depressed patients. A better understanding of the effects of cannabinoids on ECS components in depression may direct future research efforts to enhance diagnosis and treatment.

Cannabis Use is Associated With Reduced 30-Day All-cause Readmission Among Hospitalized Patients With Irritable Bowel Syndrome: A Nationwide Analysis

BACKGROUND

Cannabinoid receptors are potential therapeutic targets in a variety of gastrointestinal tract disorders. The authors hypothesize that the use of cannabis use is associated with better control of symptoms associated with irritable bowel syndrome (IBS). This study aimed to examine the utilization of inpatient services by patients with IBS who did and did not report the use of cannabis.

METHODS

This is a retrospective cohort study that utilized the 2016 Nationwide Readmissions Database. Inclusion criteria included a principal diagnosis of IBS. The primary outcome was 30-day hospital readmission rates for IBS-specific causes. Secondary outcomes included the 30-day hospital readmission rates for all causes, resource utilization, and the 5 most common principal diagnoses and independent risk factors associated with readmission.

RESULTS

Of the 7163 patients with IBS identified in the National Readmission Database, 357 reported the use of cannabis. The 30-day IBS-specific readmission rates were 1.5% in patients who reported cannabis use and 1.1% in those who did not report cannabis use (P=0.53). Among the cannabis users, none of the variables evaluated served as a significant predictor of IBS-specific readmission; median income was a predictor for readmission among those who did not report cannabis use (odds ratio, 2.77; 95% confidence interval, 1.15-6.67; P=0.02). The 30-day readmission rates for all causes were 8.1% and 12.7% for patients who did and did not report cannabis use, respectively. After adjusting for confounders, the odds of 30-day readmission for all causes were lower among patients who reported cannabis use compared with those who did not (adjusted odds ratio, 0.53; 95% confidence interval, 0.28-0.99; P=0.04). The 5 most frequent diagnoses at readmission among patients who did not report cannabis use were enterocolitis because of Clostridioides difficile, IBS without diarrhea, sepsis, noninfective gastroenteritis and colitis, and acute kidney failure. By contrast, the 5 most frequent readmission diagnoses for cannabis users were cyclical vomiting, IBS with diarrhea, endometriosis, right upper quadrant abdominal pain, and nausea with vomiting. A discharge disposition of "against medical advice" was identified as an independent risk factor for 30-day hospital readmission for all causes among patients who reported cannabis use. By contrast, higher comorbidity scores and discharges with home health care were independent predictors of 30-day hospital readmission for all causes among patients who did not report cannabis use. Private insurance was an independent factor associated with lower rates of readmission for all causes among those who did not report cannabis use.

CONCLUSION

Our review of the National Readmission Database revealed no statistically significant differences in 30-day readmission rates for IBS-specific causes when comparing patients who reported cannabis use with those who did not. However, the authors found that cannabis use was associated with reduced 30-day hospital readmission rates for all causes.

Innovative Clinical-Organizational Model to Ensure Appropriateness and Quality in the Management of Medical Cannabis: An Italian Regional Case

This work focuses on the clinical-organizational model implemented in an Italian region (Liguria) to streamline the access procedures to galenic cannabis preparations. The competent local health care authority that takes care of tracing a virtuous path to obtain common, uniform and shared protocols and ensure high standards of care is A.Li.Sa. (Azienda Ligure Sanitaria), a public organization with the function of coordination, direction and governance of the health care in the regional hospitals and health facilities. To this purpose, different working groups and a board meeting have been set up with the main role to define and develop technical standards to be applied to the prescription, preparation and dispensing of pharmaceutical forms based on therapeutic cannabis. In particular, the galenic preparations provided by the Italian Ministry of Health, described in detail in the regional standard operating protocols, are described and discussed. Moreover, the most significant data monitored from 2018 to 2020 and collected by hospitals and the evaluation of those derived from local pharmacies and health facilities are presented, discussed and compared in regards to their adherence and coherence with the Italian Institute of Health (ISS) data.

Potent T cell-mediated anti-inflammatory role of the selective CB2 agonist lenabasum in multiple sclerosis

BACKGROUND

Lenabasum is a synthetic cannabinoid receptor type-2 (CB2) agonist able to exert potent anti-inflammatory effects, but its role on T cells remains unknown.

OBJECTIVES

The present study was undertaken to investigate anti-inflammatory mechanisms of lenabasum in T lymphocyte subsets and its in vivo therapeutic efficacy in experimental autoimmune encephalomyelitis (EAE).

METHODS

Mononuclear cells from 17 healthy subjects (HS) and 25 relapsing-remitting multiple sclerosis (RRMS) patients were activated in presence or absence of lenabasum and analysed by flow cytometry and qRT-PCR. EAE mice were treated with lenabasum, and clinical score and neuroinflammation were evaluated.

RESULTS

Lenabasum significantly reduced TNF-a production from CD4+ T cells and CD8+ T cells in a dose-dependent manner in both HS and RRMS patients. In MS patients, lenabasum also reduced activation marker CD25 and inhibited IL-2 production from both T cell subsets and IFN-γ and IL-17 from committed Th1 and Th17 cells, respectively. These effects were blocked by the pretreatment with selective CB2 inverse agonist SR144528. In vivo treatment of EAE mice with lenabasum significantly ameliorated disease severity, reduced neuroinflammation and demyelination in spinal cord.

CONCLUSION

Lenabasum exerts potent T cell-mediated immunomodulatory effects, suggesting CB2 as a promising pharmacological target to counteract neuroinflammation in MS.

Expression of cannabinoid and cannabinoid-related receptors in the oral mucosa of healthy cats and cats with chronic gingivostomatitis

OBJECTIVES

Feline chronic gingivostomatitis (FCGS) is an oral disease. Cats with FCGS experience intense oral pain. Some cats remain refractory to current therapies based on dental extraction and adjuvant medical treatment; it is therefore necessary to investigate alternative therapeutic targets involved in inflammatory mechanisms and pain, namely the endocannabinoid system (ECS). The present study investigated the expression of cannabinoid receptors type 1 (CB1R) and 2 (CB2R), and cannabinoid-related receptors G protein-coupled receptor 55 (GPR55), transient receptor potential ankyrin 1 (TRPA1) and serotonin 1a receptor (5-HT1aR), in the oral mucosa of healthy cats to determine whether there was altered expression and distribution in cats with FCGS.

METHODS

Samples of caudal oral mucosa were collected from eight control cats (CTRL cats) and from eight cats with FCGS (FCGS cats). Tissue samples were processed using an immunofluorescence assay with cat-specific antibodies, and the immunolabelling of the receptors studied was semiquantitatively evaluated.

RESULTS

The mucosal epithelium of the CTRL cats showed CB1R, TRPA1 and 5-HT1aR immunoreactivity (IR), while CB2R and GPR55 IR were generally not expressed. In the CTRL cats, the subepithelial inflammatory cells expressed CB2R, GPR55 and 5-HT1aR IR. In the FCGS cats, all the receptors studied were markedly upregulated in the epithelium and inflammatory infiltrate.

CONCLUSIONS AND RELEVANCE

Cannabinoid and cannabinoid-related receptors are widely expressed in the oral mucosa of healthy cats and are upregulated during the course of FCGS. The presence of cannabinoid and cannabinoid-related receptors in healthy tissues suggests the possible role of the ECS in the homeostasis of the feline oral mucosa, while their overexpression in the inflamed tissues of FCGS cats suggests the involvement of the ECS in the pathogenesis of this disease, with a possible role in the related inflammation and pain. Based on the present findings, ECS could be considered a potential therapeutic target for patients with FCGS.

Medicinal Chemistry approach, pharmacology and neuroprotective benefits of CB2R modulators in neurodegenerative diseases

In the last decades, cannabinoid receptor 2 (CB₂R) has continued to receive attention as a key therapeutic target in neuroprotection. Indeed, several findings highlight the neuroprotective effects of CB₂R through suppression of both neuronal excitability and reactive microglia. Additionally, CB₂R seems to be a more promising target than cannabinoid receptor 1 (CB₁R) thanks to the lack of central side effects, its lower expression levels in the central nervous system (CNS), and its inducibility, since its expression enhances quickly in the brain following pathological conditions. This review aims to provide a thorough overview of the main natural and synthetic selective CB₂R modulators, their chemical classification and their potential therapeutic usefulness in neuroprotection, a crucial aspect for the treatment of neurodegenerative diseases.

Healing autism spectrum disorder with cannabinoids: a neuroinflammatory story

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with a multifactorial etiology. Latest researches are raising the hypothesis of a link between the onset of the main behavioral symptoms of ASD and the chronic neuroinflammatory condition of the autistic brain; increasing evidence of this connection is shedding light on new possible players in the pathogenesis of ASD. The endocannabinoid system (ECS) has a key role in neurodevelopment as well as in normal inflammatory responses and it is not surprising that many preclinical and clinical studies account for alterations of the endocannabinoid signaling in ASD. These findings lay the foundation for a better understanding of the neurochemical mechanisms underlying ASD and for new therapeutic attempts aimed at exploiting the renowned anti-inflammatory properties of cannabinoids to treat pathologies encompassed in the autistic spectrum. This review discusses the current preclinical and clinical evidence supporting a key role of the ECS in the neuroinflammatory state that characterizes ASD, providing hints to identify new biomarkers in ASD and promising therapies for the future.

The neuropharmacology of cannabinoid receptor ligands in central signaling pathways

The endocannabinoid system is a complex neuronal system involved in a number of biological functions, like attention, anxiety, mood, memory, appetite, reward, and immune responses. It is at the centre of scientific interest, which is driven by therapeutic promise of certain cannabinoid ligands and the changing legalization of herbal cannabis in many countries. The endocannabinoid system is a modulatory system, with endocannabinoids as retrograde neurotransmitters rather than direct neurotransmitters. Neuropharmacology of cannabinoid ligands in the brain can therefore be understood in terms of their modulatory actions through other neurotransmitter systems. The CB₁ receptor is chiefly responsible for effects of endocannabinoids and analogous ligands in the brain. An overview of the neuropharmacology of several cannabinoid receptor ligands, including endocannabinoids, herbal cannabis and synthetic cannabinoid receptor ligands is given in this review. Their mechanism of action at the endocannabinoid system is described, mainly in the brain. In addition, effects of cannabinoid ligands on other neurotransmitter systems will also be described, such as dopamine, serotonin, glutamate, noradrenaline, opioid, and GABA. In light of this, therapeutic potential and adverse effects of cannabinoid receptor ligands will also be discussed.

The Activation of Cannabinoid Type-2 Receptor with JWH-133 Protects Uterine Ischemia/Reperfusion-Induced Damage

INTRODUCTION

Uterus transplantation is a complex surgical procedure. Uterine ischemia/reperfusion (IR) damage occurring in this process may cause loss of function in the uterus. Cell damage must be prevented for a healthy uterine function and successful transplantation. Cannabinoids, with their increasing clinical use, are substances with strong anti-inflammatory and antioxidative effects and have a role in immune system regulation. However, their efficacy in uterine IR damage is still unknown. This study provides information on the potential applications cannabinoids agonist JWH-133 in uterine IR damage and, hence, in the transplant process.

METHODS

Rats were divided into 4 groups (n = 8), performed uterine IR, and treated 2 groups with JWH-133. After anesthesia, ischemia was applied for 1 h to the uterus while reperfusion was applied for 3 h. After the experiment, malondialdehyde (MDA) levels and phosphorylated nuclear factor-kappa B (p-NF-κB) expression were examined in the tissue samples. Also, cell damage was evaluated by histopathological imaging and TUNEL staining.

RESULTS

In the uterine IR group, NF-κB expression and MDA levels were detected at high levels. Histopathological examinations and TUNEL staining revealed extensive cell damage. On the other hand, in groups treated with JWH-133, dose-dependent NF-κB expression and MDA levels decreased (p < 0.05). Depending on the dose, the rate of surviving cells increased in TUNEL staining results.

CONCLUSION

The results showed that JWH-133 was effective in reducing uterine IR damage. Cannabinoids may be a new alternative that may be used in the transplantation process in the future.

Current application of cannabidiol (CBD) in the management and treatment of neurological disorders

Cannabidiol (CBD), which is nonintoxicating pharmacologically relevant constituents of Cannabis, demonstrates several beneficial effects. It has been found to have antioxidative, anti-inflammatory, and neuroprotective effects. As the medicinal use of CBD is gaining popularity for treatment of various disorders, the recent flare-up of largely unproven and unregulated cannabis-based preparations on medical therapeutics may have its greatest impact in the field of neurology. Currently, as lot of clinical trials are underway, CBD demonstrates remarkable potential to become a supplemental therapy in various neurological conditions. It has shown promise in the treatment of neurological disorders such as anxiety, chronic pain, trigeminal neuralgia, epilepsy, and essential tremors as well as psychiatric disorders. While recent FDA-approved prescription drugs have demonstrated safety, efficacy, and consistency enough for regulatory approval in spasticity in multiple sclerosis (MS) and in Dravet and Lennox-Gastaut Syndromes (LGS), many therapeutic challenges still remain. In the current review, the authors have shed light on the application of CBD in the management and treatment of various neurological disorders.

Potential Adverse Drug Events with Tetrahydrocannabinol (THC) Due to Drug-Drug Interactions

Tetrahydrocannabinol (THC) is the primary psychoactive ingredient in cannabis. While the safety of THC and cannabis has been extrapolated from millennia of recreational use, medical marijuana programs have increased exposure among medically complex individuals with comorbid conditions and many co-prescribed medications. Thus, THC should be recognized as a pharmacologically complex compound with potential for drug–drug interactions and adverse drug events. This review summarizes potential adverse drug events related to THC when combined with other medications. Metabolic drug–drug interactions are primarily due to THC conversion by CYP3A4 and CYP2C9, which can be impacted by several common medications. Further, CYP2C9 polymorphisms are highly prevalent in certain racial groups (up to 35% in Caucasians) and increase the bioavailability of THC. THC also has broad interactions with drug-metabolizing enzymes and can enhance adverse effects of other medications. Pharmacodynamic interactions include neurological effects, impact on the cardiovascular system, and risk of infection. General clinical recommendations for THC use include starting with low doses and titrating to desired effects. However, many interactions may be unavoidable, dose-limiting, or a barrier to THC-based therapy. Future work and research must establish sufficient data resources to capture medical marijuana use for such studies. Meanwhile, clinicians should balance the potential risks of THC and cannabis and the lack of strong evidence of efficacy in many conditions with patient desires for alternative therapy.

Potential Adverse Drug Events and Drug-Drug Interactions with Medical and Consumer Cannabidiol (CBD) Use

Cannabidiol (CBD) is ubiquitous in state-based medical cannabis programs and consumer products for complementary health or recreational use. CBD has intrinsic pharmacologic effects and associated adverse drug events (ADEs) along with the potential for pharmacokinetic and pharmacodynamic drug–drug interactions (DDIs). Given CBD use among patients with complex conditions and treatment regimens, as well as its expanded consumer use, awareness of potential safety issues with CBD is needed. Prescribing information for federally approved products containing CBD were reviewed. Data on ADEs and DDIs were extracted and summarized. Nearly one-half of CBD users experienced ADEs, which displayed a general dose-response relationship. Common ADEs include transaminase elevations, sedation, sleep disturbances, infection, and anemia. Given CBD effects on common biological targets implicated in drug metabolism (e.g., CYP3A4/2C19) and excretion (e.g., P-glycoprotein), the potential for DDIs with commonly used medication is high. General clinical recommendations of reducing substrate doses, monitoring for ADEs, and finding alternative therapy should be considered, especially in medically complex patients. CBD is implicated as both a victim and perpetrator of DDIs and has its own ADE profile. These effects should be considered in the risk-benefit assessment of CBD therapy and patients and consumers made aware of potential safety issues with CBD use.

Activation of cannabinoid 2 receptor relieves colonic hypermotility in a rat model of irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a common disease with intestinal dysmotility, whose mechanism remains elusive. The endocannabinoid system is emerging as an important modulator of gastrointestinal (GI) motility in multiple diseases, but its involvement in IBS is unknown. We aimed to determine whether cannabinoid 2 (CB2) receptor modulates intestinal motility associated with stress-induced IBS.

METHODS

A rat IBS model was established by chronic water avoidance stress (WAS). Colonic pathological alterations were detected histologically and intestinal motility was assessed by intestinal transit time (ITT) and fecal water content (FWC). Visceral sensitivity was determined by visceromotor response (VMR) to colorectal distension (CRD). Real-time PCR, western blot, and immunostaining were performed to identify colonic CB2 receptor expression. Colonic muscle strip contractility was studied by isometric transducers and nitric oxide (NO) was detected by the Griess test. The effects of AM1241, a selective agonist of CB2 receptors, on colonic motility were examined.

KEY RESULTS

After 10 days of WAS exposure, ITT was decreased and FWC elevated while VMR magnitude in response to CRD was significantly enhanced. Colon CB2 protein and mRNA levels increased and density of CB2-positive macrophages in the mucosa and enteric neurons in the myenteric plexus was higher than in controls. Pharmacological enhancement of CB2 activity by AM1241 relieved colonic hypermotility in WAS rats in a concentration-dependent manner via inhibition of p38 phosphorylation and elevation of NO production.

CONCLUSION

CB2 receptor may exert an important inhibitory effect in stress-induced colonic hypermotility by modulating NO synthesis through p38 mitogen-activated protein kinase signaling. AM1241 could be used as a potential drug to treat disorders with colonic hypermotility.

Medical Cannabis for Adult Attention Deficit Hyperactivity Disorder: Sociological Patient Case Report of Cannabinoid Therapeutics in Finland

This paper presents a detailed patient case report of a male patient who was diagnosed in adulthood (aged 33) with attention deficit hyperactivity disorder (ADHD) and treated initially with immediate-release methylphenidate (Ritalin® 10 mg twice daily). After experiencing adverse effects from prolonged use of this medication and afterwards other medications that were prescribed as alternatives, the patient discovered that cannabinoid therapeutics (CT) had been experimented inside the EU area to treat patients with ADHD. Subsequently, he was evaluated by a physician in Germany (June 2010) who prescribed CT (Bedrocan®, Bediol®). A Finnish neurologist later confirmed the two prescribed medicines (Bedrocan®, October 2010; Bediol®, May 2011) in the patient's own country of permanent residence (Finland). During a 5-year period of access, Bedrocan®, which mainly contains Δ9-tetrahydrocannabinol (Δ9-THC), was found to be helpful in alleviating the patient's ADHD symptoms, in particular poor tolerance to frustration, outbursts of anger, boredom, and problems related to concentration. The second CT medication, Bediol®, which contains both Δ9-THC and the phytocannabinoid cannabidiol, was found to neutralize the excessive dronabinol effects of Bedrocan® as well as zo offer other medical benefits (e.g., improved sleep). In addition to the case report, this paper also offers a brief review of the literature surrounding the medical benefits of CT for AD(H)D, which includes observational studies, clinical case reports, and one randomized clinical experiment. This paper also briefly discusses the endocannabinoid system in relation to ADHD, although more preclinical and clinical research is warranted to establish the optimal levels of cannabinoids, terpenes, and dosing regimens, which vary between different ADHD patients.

Endocannabinod Signal Dysregulation in Autism Spectrum Disorders: A Correlation Link between Inflammatory State and Neuro-Immune Alterations

Several studies highlight a key involvement of endocannabinoid (EC) system in autism pathophysiology. The EC system is a complex network of lipid signaling pathways comprised of arachidonic acid-derived compounds (anandamide, AEA) and 2-arachidonoyl glycerol (2-AG), their G-protein-coupled receptors (cannabinoid receptors CB1 and CB2) and the associated enzymes. In addition to autism, the EC system is also involved in several other psychiatric disorders (i.e., anxiety, major depression, bipolar disorder and schizophrenia). This system is a key regulator of metabolic and cellular pathways involved in autism, such as food intake, energy metabolism and immune system control. Early studies in autism animal models have demonstrated alterations in the brain's EC system. Autism is also characterized by immune system dysregulation. This alteration includes differential monocyte and macrophage responses, and abnormal cytokine and T cell levels. EC system dysfunction in a monocyte and macrophagic cellular model of autism has been demonstrated by showing that the mRNA and protein for CB2 receptor and EC enzymes were significantly dysregulated, further indicating the involvement of the EC system in autism-associated immunological disruptions. Taken together, these new findings offer a novel perspective in autism research and indicate that the EC system could represent a novel target option for autism pharmacotherapy.

Cannabidiol: State of the art and new challenges for therapeutic applications

Over the past years, several lines of evidence support a therapeutic potential of Cannabis derivatives and in particular phytocannabinoids. Δ⁹-THC and cannabidiol (CBD) are the most abundant phytocannabinoids in Cannabis plants and therapeutic application for both compounds have been suggested. However, CBD is recently emerging as a therapeutic agent in numerous pathological conditions since devoid of the psychoactive side effects exhibited instead by Δ⁹-THC. In this review, we highlight the pharmacological activities of CBD, its cannabinoid receptor-dependent and -independent action, its biological effects focusing on immunomodulation, angiogenetic properties, and modulation of neuronal and cardiovascular function. Furthermore, the therapeutic potential of cannabidiol is also highlighted, in particular in nuerological diseases and cancer.

Tamoxifen Isomers and Metabolites Exhibit Distinct Affinity and Activity at Cannabinoid Receptors: Potential Scaffold for Drug Development

Tamoxifen (Tam) is a selective estrogen receptor (ER) modulator (SERM) that is an essential drug to treat ER-positive breast cancer. Aside from known actions at ERs, recent studies have suggested that some SERMs like Tam also exhibit novel activity at cannabinoid subtype 1 and 2 receptors (CB1R and CB2Rs). Interestingly, cis- (E-Tam) and trans- (Z-Tam) isomers of Tam exhibit over a 100-fold difference in affinity for ERs. Therefore, the current study assessed individual isomers of Tam and subsequent cytochrome P450 metabolic products, 4-hydroxytamoxifen (4OHT) and 4-hydroxy-N-desmethyl tamoxifen (End) for affinity and activity at CBRs. Results showed that Z-4OHT, but not Z-Tam or Z-End, exhibits higher affinity for both CB1 and CB2Rs relative to the E-isomer. Furthermore, Z- and E-isomers of Tam and 4OHT show slightly higher affinity for CB2Rs, while both End isomers are relatively CB1R-selective. When functional activity was assessed by G-protein activation and regulation of the downstream effector adenylyl cyclase, all isomers examined act as full CB1 and CB2R inverse agonists. Interestingly, Z-Tam appears to be more efficacious than the full inverse agonist AM630 at CB2Rs, while both Z-Tam and Z-End exhibit characteristics of insurmountable antagonism at CB1 and CB2Rs, respectively. Collectively, these results suggest that the SERMs Tam, 4OHT and End elicit ER-independent actions via CBRs in an isomer-specific manner. As such, this novel structural scaffold might be used to develop therapeutically useful drugs for treatment of a variety of diseases mediated via CBRs.

Metabolism of Anandamide by Human Cytochrome P450 2J2 in the Reconstituted System and Human Intestinal Microsomes

According to the Centers for Disease Control and Prevention, the incidence of inflammatory bowel diseases (IBD) is about 1 in 250 people in the United States. The disease is characterized by chronic or recurring inflammation of the gut. Because of the localization of the endocannabinoid system in the gastrointestinal tract, it may be a potential pharmacologic target for the treatment of IBD and other diseases. Fatty acid amide hydrolase (FAAH) is a potential candidate because it is upregulated in IBD. FAAH hydrolyzes and, as a consequence, inactivates anandamide (AEA), a prominent endocannabinoid. Inhibition of FAAH would lead to increases in the amount of AEA oxidized by cytochrome P450s (P450s). CYP2J2, the major P450 epoxygenase expressed in the heart, is also expressed in the intestine and has previously been reported to oxidize AEA. We have investigated the possibility that it may play a role in AEA metabolism in the gut and have demonstrated that purified human CYP2J2 metabolizes AEA to form the 20-hydroxyeicosatetraenoic acid ethanolamide (HETE-EA) and several epoxygenated products, including the 5,6-, 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acid ethanolamides (EET-EAs), in the reconstituted system. Kinetic studies suggest that the KM values for these products range from approximately 10 to 468 μM and the kcat values from 0.2 to 23.3 pmol/min per picomole of P450. Human intestinal microsomes, which express CYP2J2, metabolize AEA to give the 5,6-, 8,9-, and 11,12-EET-EAs, as well as 20-HETE-EA. Studies using specific P450 inhibitors suggest that although CYP2J2 metabolizes AEA, it is not the primary P450 responsible for AEA metabolism in human intestines.

Antagonism of cannabinoid receptor 2 pathway suppresses IL-6-induced immunoglobulin IgM secretion

Background

Cannabinoid receptor 2 (CB2) is expressed predominantly in the immune system, particularly in plasma cells, raising the possibility that targeting the CB2 pathway could yield an immunomodulatory effect. Although the role of CB2 in mediating immunoglobulin class switching has been reported, the effects of targeting the CB2 pathway on immunoglobulin secretion per se remain unclear.

Methods

Human B cell line SKW 6.4, which is capable of differentiating into IgM-secreting cells once treated with human IL-6, was employed as the cell model. SKW 6.4 cells were incubated for 4 days with CB2 ligands plus IL-6 (100 U/ml). The amount of secreted IgM was determined by an ELISA. Cell proliferation was determined by the ³H-Thymidine incorporation assay. Signal molecules involved in the modulation of IgM secretion were examined by real-time RT-PCR and Western blot analyses or by using their specific inhibitors.

Results

We demonstrated that CB2 inverse agonists SR144528 and AM630, but not CB2 agonist HU308 or CB1 antagonist SR141716, effectively inhibited IL-6-induced secretion of soluble IgM without affecting cell proliferation as measured by thymidine uptake. SR144528 alone had no effects on the basal levels of IgM in the resting cells. These effects were receptor mediated, as pretreatment with CB2 agonist abrogated SR144528-mediated inhibition of IL-6 stimulated IgM secretion. Transcription factors relevant to B cell differentiation, Bcl-6 and PAX5, as well as the protein kinase STAT3 pathway were involved in the inhibition of IL-6-induced IgM by SR144528.

Conclusions

These results uncover a novel function of CB2 antagonists and suggest that CB2 ligands may be potential modulators of immunoglobulin secretion.

CB2 receptor deficiency increases amyloid pathology and alters tau processing in a transgenic mouse model of Alzheimer's disease

The endocannabinoid CB2 receptor system has been implicated in the neuropathology of Alzheimer's disease (AD). In order to investigate the impact of the CB2 receptor system on AD pathology, a colony of mice with a deleted CB2 receptor gene, CNR2, was established on a transgenic human mutant APP background for pathological comparison with CB2 receptor-sufficient transgenic mice. J20 APP (PDGFB-APPSwInd) mice were bred over two generations with CNR2(-/-) (Cnr2(tm1Dgen)/J) mice to produce a colony of J20 CNR2(+/+) and J20 CNR2(-/-) mice. Seventeen J20 CNR2(+/+) mice (12 females, 5 males) and 16 J20 CNR2(-/-) mice (11 females, 5 males) were killed at 12 months, and their brains were interrogated for AD-related pathology with both biochemistry and immunocytochemistry (ICC). In addition to amyloid-dependent endpoints such as soluble Aβ production and plaque deposition quantified with 6E10 staining, the effect of CB2 receptor deletion on total soluble mouse tau production was assayed by using a recently developed high-sensitivity assay. Results revealed that soluble Aβ42 and plaque deposition were significantly increased in J20 CNR2(-/-) mice relative to CNR2(+/+) mice. Microgliosis, quantified with ionized calcium-binding adapter molecule 1 (Iba-1) staining, did not differ between groups, whereas plaque associated microglia was more abundant in J20 CNR2(-/-) mice. Total tau was significantly suppressed in J20 CNR2(-/-) mice relative to J20 CNR2(+/+) mice. The results confirm the constitutive role of the CB2 receptor system both in reducing amyloid plaque pathology in AD and also support tehpotential of cannabinoid therapies targeting CB2 to reduce Aβ; however, the results suggest that interventions may have a divergent effect on tau pathology.

CB₂ receptor deficiency increases amyloid pathology and alters tau processing in a transgenic mouse model of Alzheimer's disease

The endocannabinoid CB₂ receptor system has been implicated in the neuropathology of Alzheimer's disease (AD). In order to investigate the impact of the CB₂ receptor system on AD pathology, a colony of mice with a deleted CB₂ receptor gene, CNR2, was established on a transgenic human mutant APP background for pathological comparison with CB₂ receptor-sufficient transgenic mice. J20 APP (PDGFB-APPSwInd) mice were bred over two generations with CNR2⁻/⁻ (Cnr2(tm1Dgen)/J) mice to produce a colony of J20 CNR2⁺/⁺ and J20 CNR2⁻/⁻ mice. Seventeen J20 CNR2⁺/⁺ mice (12 females, 5 males) and 16 J20 CNR2⁻/⁻ mice (11 females, 5 males) were killed at 12 months, and their brains were interrogated for AD-related pathology with both biochemistry and immunocytochemistry (ICC). In addition to amyloid-dependent endpoints such as soluble Aβ production and plaque deposition quantified with 6E10 staining, the effect of CB2 receptor deletion on total soluble mouse tau production was assayed by using a recently developed high-sensitivity assay. Results revealed that soluble Aβ42 and plaque deposition were significantly increased in J20 CNR2⁻/⁻ mice relative to CNR2⁺/⁺ mice. Microgliosis, quantified with ionized calcium-binding adapter molecule 1 (Iba-1) staining, did not differ between groups, whereas plaque associated microglia was more abundant in J20 CNR2⁻/⁻ mice. Total tau was significantly suppressed in J20 CNR2⁻/⁻ mice relative to J20 CNR2⁺/⁺ mice. The results confirm the constitutive role of the CB₂ receptor system both in reducing amyloid plaque pathology in AD and also support tehpotential of cannabinoid therapies targeting CB₂ to reduce Aβ; however, the results suggest that interventions may have a divergent effect on tau pathology.

Epigenetic mechanisms and endocannabinoid signalling

The endocannabinoid system, composed of endogenous lipids, their target receptors and metabolic enzymes, has been implicated in multiple biological functions in health and disease, both in the central nervous system and in peripheral organs. Despite the exponential growth of experimental evidence on the key role of endocannabinoid signalling in basic cellular processes, and on its potential exploitation for therapeutic interventions, much remains to be clarified about the respective regulatory mechanisms. Epigenetics refers to a set of post-translational modifications that regulate gene expression without causing variation in DNA sequence, endowed with a major impact on signal transduction pathways. The epigenetic machinery includes DNA methylation, histone modifications, nucleosome positioning and non-coding RNAs. Due to the reversibility of epigenetic changes, an emerging field of interest is the possibility of an 'epigenetic therapy' that could possibly be applied also to endocannabinoids. Here, we review current knowledge of epigenetic regulation of endocannabinoid system components under both physiological and pathological conditions, as well as the epigenetic changes induced by endocannabinoid signalling.

Type 2 diabetes associated changes in the plasma non-esterified fatty acids, oxylipins and endocannabinoids

Type 2 diabetes has profound effects on metabolism that can be detected in plasma. While increases in circulating non-esterified fatty acids (NEFA) are well-described in diabetes, effects on signaling lipids have received little attention. Oxylipins and endocannabinoids are classes of bioactive fatty acid metabolites with many structural members that influence insulin signaling, adipose function and inflammation through autocrine, paracrine and endocrine mechanisms. To link diabetes-associated changes in plasma NEFA and signaling lipids, we quantitatively targeted >150 plasma lipidome components in age- and body mass index-matched, overweight to obese, non-diabetic (n = 12) and type 2 diabetic (n = 43) African-American women. Diabetes related NEFA patterns indicated ∼60% increase in steroyl-CoA desaturase activity and ∼40% decrease in very long chain polyunsaturated fatty acid chain shortening, patterns previously associated with the development of nonalcoholic fatty liver disease. Further, epoxides and ketones of eighteen carbon polyunsaturated fatty acids were elevated >80% in diabetes and strongly correlated with changes in NEFA, consistent with their liberation during adipose lipolysis. Endocannabinoid behavior differed by class with diabetes increasing an array of N-acylethanolamides which were positively correlated with pro-inflammatory 5-lipooxygenase-derived metabolites, while monoacylglycerols were negatively correlated with body mass. These results clearly show that diabetes not only results in an increase in plasma NEFA, but shifts the plasma lipidomic profiles in ways that reflect the biochemical and physiological changes of this pathological state which are independent of obesity associated changes.

The atypical cannabinoid O-1602 stimulates food intake and adiposity in rats

AIMS

Cannabinoids are known to control energy homeostasis. Atypical cannabinoids produce pharmacological effects via unidentified targets. We sought to investigate whether the atypical cannabinoid O-1602 controls food intake and body weight.

METHODS

The rats were injected acutely or subchronically with O-1602, and the expression of several factors involved in adipocyte metabolism was assessed by real-time polymerase chain reaction. In vivo findings were corroborated with in vitro studies incubating 3T3-L1 adipocytes with O-1602, and measuring intracellular calcium and lipid accumulation. Finally, as some reports suggest that O-1602 is an agonist of the putative cannabinoid receptor GPR55, we tested it in mice lacking GPR55.

RESULTS

Central and peripheral administration of O-1602 acutely stimulates food intake, and chronically increases adiposity. The hyperphagic action of O-1602 is mediated by the downregulation of mRNA and protein levels of the anorexigenic neuropeptide cocaine- and amphetamine-regulated transcript. The effects on fat mass are independent of food intake, and involve a decrease in the expression of lipolytic enzymes such as hormone sensitive lipase and adipose triglyceride lipase in white adipose tissue. Consistently, in vitro data showed that O-1602 increased the levels of intracellular calcium and lipid accumulation in adipocytes. Finally, we injected O-1602 in GPR55 -/- mice and found that O-1602 was able to induce feeding behaviour in GPR55-deficient mice.

CONCLUSIONS

These findings show that O-1602 modulates food intake and adiposity independently of GPR55 receptor. Thus atypical cannabinoids may represent a novel class of molecules involved in energy balance.

The endogenous cannabinoid system in the gut of patients with inflammatory bowel disease

Activation of cannabinoid receptors (CBs) by endocannabinoids impacts on a number of gastrointestinal functions. Recent data indicate that CB1 agonists improve 2,4-dinitrobenzene sulfonic acid-induced colitis in mice, thus suggesting a role for the endocannabinoid agonist anandamide (AEA) in protecting the gut against inflammation. We here examined the gut endocannabinoid system in inflammatory bowel disease (IBD) patients, and investigated the ex vivo and in vitro effects of the non-hydrolysable AEA analog methanandamide (MAEA) on the mucosal proinflammatory response. The content of AEA, but not of 2-arachidonoyl-glycerol and N-palmitoylethanolamine, was significantly lower in inflamed than uninflamed IBD mucosa, and this was paralleled by lower activity of the AEA-synthesizing enzyme N-acyl-phosphatidylethanolamine-specific phospholipase D and higher activity of the AEA-degrading enzyme fatty acid amide hydrolase. MAEA significantly downregulated interferon-γ and tumor necrosis factor-α secretion by both organ culture biopsies and lamina propria mononuclear cells. Although these results are promising, further studies are needed to determine the role of cannabinoid pathways in gut inflammation.

Immunoregulation of a CB2 receptor agonist in a murine model of neuroAIDS

Chronic HIV-1 infection commonly affects behavioral, cognitive, and motor functions in the infected human host and is commonly referred to as HIV-1-associated neurocognitive disorders (HAND). This occurs, in measure, as a consequence of ingress of leukocytes into brain perivascular regions. Such cells facilitate viral infection and disease by eliciting blood-brain barrier and neuronal network dysfunctions. Previous works demonstrated that the endocannabinoid system modulates neuroimmunity and as such neuronal and glial functions. Herein, we investigated CB2R receptor expression in murine HIV-1 encephalitis (HIVE) and the abilities of a highly selective CB2R agonist, Gp1a, to modulate disease. HIV-1-infected human monocyte-derived macrophages were injected into the caudate and putamen of immunodeficient mice reconstituted with human peripheral blood lymphocytes (hu-PBL/HIVE). Brains of hu-PBL/HIVE mice showed microglial activation and increased expression of CB2R, but not CB1R or GPR55. Gp1a substantively reduced infiltration of human cells into the mouse brain and reduced HLA DQ activation. Gp1a down modulated CCR5 expression on human cells in the spleen with an increase in Fas ligand expression. Our results support the notion that CB2 receptor agonists may be a viable therapeutic candidate for HAND.

Functional consequences of nonsynonymous single nucleotide polymorphisms in the CB2 cannabinoid receptor

OBJECTIVE

To test the hypothesis that the two nonsynonymous single nucleotide polymorphisms at the CB2 cannabinoid receptor gene may have functional consequences on human CB2.

METHODS

Q63R, H316Y, and Q63R/H316 mutations were made in recombinant human CB2 by the method of site-directed mutagenesis. After these mutant CB2 receptors were stably transfected into HEK293 cells, ligand binding, ligand-induced activity, and constitutive activity assays were performed to test the functional significance of these mutations.

RESULTS

In general, our results showed that the CB2 polymorphic receptors are able to bind cannabinoid ligands and mediate signal transduction. However, in ligand-induced cyclic AMP accumulation assays, the cannabinoid agonists WIN55212-2 and 2-arachidonoylglycerol had reduced efficacy in cells expressing the polymorphic receptors as compared with the CB2 wild-type receptor. Furthermore, in constitutive activity assays, the H316Y and Q63R/H316Y polymorphic receptors exhibited higher constitutive activity than the CB2 wild-type receptor.

CONCLUSION

Our data shows that the presence of the polymorphisms at both positions 63 and 316 produce alterations in the CB2 receptor functions. Moreover, these findings strengthen the idea that the CB2 polymorphic receptors may contribute to the etiology of certain diseases.

The levels of the endocannabinoid receptor CB2 and its ligand 2-arachidonoylglycerol are elevated in endometrial carcinoma

The endocannabinoid system plays protective roles against the growth and the spreading of several types of carcinomas. Because estrogens regulate this system both in physiological states and cancer, in this paper we evaluated its involvement in endometrial carcinoma, a well-known estrogen-dependent tumor. To test whether the endocannabinoid system is expressed in endometrial cancer, tissue samples were collected both from 18 patients undergoing surgical treatment for endometrial adenocarcinoma and 16 healthy age-matched controls, and treated for Western blot and immunohistochemical analysis. Moreover, tissues were dounce homogenized and submitted to endocannabinoid measurement by liquid chromatography-mass spectrometry. To evaluate the physiological role of the endocannabinoid system, a human endometrial cancer cell-line (AN3CA) was used and transiently transfected with a plasmid containing the cDNA for the endocannabinoid receptor CB(2). Cells were incubated for 48 h with an agonist (JWH133) (10 mum) or antagonist (SR144528) (1 mum) of CB(2) 24 h after transfection, and cell proliferation was measured by the 3-[4,5-dimethyltiazol-2yl]-2,5 diphenyltetrazolium bromide formazan assay. In human endometrial carcinoma biopsies the expression of CB(2) receptor and the levels of its ligand, 2-arachidonoylglycerol increased, whereas monoacylglycerol lipase, an enzyme responsible for 2-arachidonoylglycerol degradation, was down-regulated. Immunohistochemical analysis revealed that CB(2) was overexpressed only in malignant endometrial cells. CB(2)-overexpressing AN3CA cells showed a significant reduction in cell vitality compared with parental AN3CA cells: incubation with the selective CB(2) antagonist SR144128 restored the viability of CB(2)-overexpressing cells to that of untransfected cells. In conclusion, the endocannabinoid system seems to play an important role in human endometrial carcinoma, and modulation of CB(2) activity/expression may account for a tumor-suppressive effect.

Sex-dependent alterations in response to maternal deprivation in rats

We review here our latest results regarding short- and long-term effects of a neonatal maternal deprivation (MD) stress [24h at postnatal day (PND) 9] on diverse psychoneuroimmunoendocrine parameters, pointing out the existence of numerous sexual dimorphisms. Behavioral changes observed in MD animals might be at least in part attributable to neurodevelopmental effects of MD-induced elevated corticosterone levels. Our findings of short-term effects of MD on hippocampal and cerebellar neurons and glial cells appear to support this hypothesis. However, it is important to note that these cellular effects were more marked in males than in females. Moreover, in analyzing the effects of this neonatal stress on the endocannabinoid system (hippocampal endocannabinoid levels and CB1 receptors) we have also found that males were more affected by MD. Since all these sexual dimorphisms were found at an early neonatal age (PND 13), they are attributable to organizational effects of gonadal steroids. We discuss the potential implications of the elevated corticosterone and decreased leptin levels shown by MD animals in their diverse functional alterations, including the above mentioned neural effects as well as the intriguing persistent deficit in their immunological system. We also emphasize the necessity of analyzing the important influence of sex as regards the specific consequences of early life stress.

Characterizing cannabinoid CB2 receptor ligands using DiscoveRx PathHunter beta-arrestin assay

The authors have characterized a set of cannabinoid CB(2) receptor ligands, including triaryl bis sulfone inverse agonists, in a cell-based receptor/beta-arrestin interaction assay (DiscoveRx PathHunter). The results were compared with results using a competitive ligand binding assay, and with effects on forskolin-stimulated cAMP levels (PerkinElmer LANCE). The authors show good correlation between the 3 assay systems tested, with the beta-arrestin protein complementation assay exhibiting a more robust signal than the cAMP assay for cannabinoid CB(2) agonists. Further assay validation shows that DiscoveRx PathHunter HEK293 CB(2) beta-arrestin assay can be carried out from cryopreserved cell suspensions, eliminating variations caused by the need for multiple cell pools during live cell screening campaigns. These results, and the authors' results evaluating a test set of random library compounds, validate the use of ligand-induced interaction between the human cannabinoid CB(2) receptor and beta-arrestin as an appropriate and valuable screening platform for compounds specific for the cannabinoid CB(2) receptor.

[Endocannabinoid system and bowel inflammation]

The endocannabinoid system is an important regulatory system of multiple functions of the body in all vertebrates. There are 2 specific receptors, CB1 and CB2, through which the cannabinoids exert their effect. CB1-receptors mainly express themselves in myenteric plexuses and submucosal epithelium of the gastrointestinal tract, suggesting their implication in the inhibition of the peristalsis and gastrointestinal contraction. CB2-receptors are expressed in the tissue and immune cells, such as T and B-lymphocytes, monocytes and polymorphonuclear neutrophils, exerting an immunomodulator effect. The role of the endocannabinoid system is not completely known, but there is enough evidence that confirms an important role in the decrease of inflammation through the reduction of the release of pro-inflammatory cytokines. Therefore, it may exert a protective role in many of the points where the homeostasis breaks in inflammatory bowel disease. Research about the mechanisms and effects of the endocannabinoid system in the gastrointestinal tract will allow advancing in the therapy of this illness.

Endocannabinoids in Alzheimer's disease and their impact on normative cognitive performance: a case-control and cohort study

BACKGROUND

Neuropathological, animal, and cell culture studies point to a role for the body's own endogenous cannabinoids (eCBs) system in Alzheimer's disease (AD) pathology and treatment. To date, no published studies have investigated the potential utility of circulating eCBs as diagnostic biomarkers for AD or the impact of central eCBs on cognition.

RESULTS

In comparison with healthy controls, there were no significant differences in measured eCB concentrations in plasma samples from patients with AD. Detectable eCBs in cerebrospinal fluid (CSF) had no relationship to cognitive performance in healthy controls at risk for AD. In pooled plasma samples, an inverse correlation was observed between plasma levels of the eCB 2-AG (2-arachidonoylglycerol) and TNF-alpha (r = -0.41, p < 0.02).

CONCLUSION

These results suggest that circulating endocannabinoids do not have utility as diagnostic biomarkers for AD and do not have a robust correlation with cognitive performance. Circulating levels of 2-AG may downregulate TNF-alpha production.

Distinct risk factor profiles for human papillomavirus type 16-positive and human papillomavirus type 16-negative head and neck cancers

BACKGROUND

High-risk types of human papillomavirus (HPV), including HPV-16, cause a subgroup of head and neck squamous cell carcinomas (HNSCCs). We examined whether the risk factors for HPV-16-positive HNSCCs are similar to those for HPV-16-negative HNSCCs in a hospital-based case-control study.

METHODS

Case subjects (n = 240) diagnosed with HNSCC at the Johns Hopkins Hospital from 2000 through 2006 were stratified by tumor HPV-16 status as determined by in situ hybridization. Two control subjects (n = 322) without cancer were individually matched by age and sex to each HPV-16-positive and HPV-16-negative case subject. Data on risk behaviors were obtained by use of audio computer-assisted self-interview technology. Multivariable conditional logistic regression models were used to estimate the odds ratios (ORs) for HPV-16-positive HNSCC and HPV-16-negative HNSCC associated with risk factors. All statistical tests were two-sided.

RESULTS

HPV-16 was detected in 92 of 240 case subjects. HPV-16-positive HNSCC was independently associated with several measures of sexual behavior and exposure to marijuana but not with cumulative measures of tobacco smoking, alcohol drinking, or poor oral hygiene. Associations increased in strength with increasing number of oral sex partners (P(trend) = .01) and with increasing intensity (joints per month, P(trend) = .007), duration (in years, P(trend) = .01), and cumulative joint-years (P(trend) = .003) of marijuana use. By contrast, HPV-16-negative HNSCC was associated with measures of tobacco smoking, alcohol drinking, and poor oral hygiene but not with any measure of sexual behavior or marijuana use. Associations increased in strength with increasing intensity (cigarettes per day), duration, and cumulative pack-years of tobacco smoking (for all, P(trend) < .001), increasing years of heavy alcohol drinking (> or = 15 years of 14 drinks per week; P(trend) = .03), and increasing number of lost teeth (P(trend) = .001). Compared with subjects who neither smoked tobacco nor drank alcohol, those with heavy use of tobacco (> or = 20 pack-years) and alcohol had an increased risk of HPV-16-negative HNSCC (OR = 4.8, 95% confidence interval [CI] = 1.8 to 12) but not of HPV-16-positive HNSCC (OR = 0.67, 95% CI = 0.29 to 1.9).

CONCLUSIONS

HPV-16-positive HNSCCs and HPV-16-negative HNSCCs have different risk factor profiles, indicating that they should be considered to be distinct cancers.

Pharmacological evaluation of a novel cannabinoid 2 (CB2) ligand, PF-03550096, in vitro and in vivo by using a rat model of visceral hypersensitivity

Previous studies have shown that cannabinoid 2 (CB(2))-receptor agonists might have analgesic effects on visceral hypersensitivity. To extend these results, we have determined the pharmacological characteristics of a newly designed CB(2) ligand, N-[(1S)-1-(aminocarbonyl)-2,2-dimethylpropyl]-3-(3-hydroxy-3-methylbutyl)-2-oxo-2,3-dihydro-1H-benzimidazole-1-carboxamide (PF-03550096), in vitro and in vivo. PF-03550096 showed high affinity to human (K(i) = 7.9 +/- 1.7 nM) and rat CB(2) receptors (K(i) = 47 +/- 5.6 nM). In a cell-based functional assay, PF-03550096 behaved as a full agonist and showed high selectivity for human CB(2) receptors. Orally administered PF-03550096 (3, 10 mg/kg) inhibited the 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced decrease in colonic pain threshold with statistical significance. The inhibitory effect of PF-03550096 (10 mg/kg) was significantly reversed by a selective CB(2) antagonist, N-(1S)-endo-1,3,3-trimethylbicyclo[2.2.1]heptan-2-yl-5-(4-chloro-3-methylphenyl)-1(4-methylbenzyl)-pyrazole-3-carboxamide (SR144528), while SR144528 itself did not modify colonic pain threshold. These results indicate that PF-03550096 is a potent CB(2) agonist and possesses efficacy in a rat model of visceral hypersensitivity.

Fatty acid amide hydrolase: a gate-keeper of the endocannabinoid system

The family of endocannabinoids contains several polyunsaturated fatty acid amides such as anandamide (AEA), but also esters such as 2-arachidonoylglycerol (2-AG). These compounds are the main endogenous agonists of cannabinoid receptors, able to mimic several pharmacological effects of Delta9-tetrahydrocannabinol (Delta9-THC), the active principle of Cannabis sativa preparations like hashish and marijuana. The activity of AEA at its receptors is limited by cellular uptake, through a putative membrane transporter, followed by intracellular degradation by fatty acid amide hydrolase (FAAH). Growing evidence demonstrates that FAAH is the critical regulator of the endogenous levels of AEA, suggesting that it may serve as an attractive therapeutic target for the treatment of human disorders. In particular, FAAH inhibitors may be next generation therapeutics of potential value for the treatment of pathologies of the central nervous system, and of peripheral tissues. Investigations into the structure and function of FAAH, its biological and therapeutic implications, as well as a description of different families of FAAH inhibitors, are the topic of this chapter.

Cannabinoid CB2 receptors in the gastrointestinal tract: a regulatory system in states of inflammation

The emerging potential for the cannabinoid (CB) system in modulating gastrointestinal inflammation has gained momentum over the last few years. Traditional and anecdotal use of marijuana for gastrointestinal disorders, such as diarrhoea and abdominal cramps is recognized, but the therapeutic benefit of cannabinoids in the 21st century is overshadowed by the psychoactive problems associated with CB1 receptor activation. However, the presence and function of the CB2 receptor in the GI tract, whilst not yet well characterized, holds great promise due to its immunomodulatory roles in inflammatory systems and its lack of psychotropic effects. This review of our current knowledge of CB2 receptors in the gastrointestinal tract highlights its role in regulating abnormal motility, modulating intestinal inflammation and limiting visceral sensitivity and pain. CB2 receptors represent a braking system and a pathophysiological mechanism for the resolution of inflammation and many of its symptoms. CB2 receptor activation therefore represents a very promising therapeutic target in gastrointestinal inflammatory states where there is immune activation and motility dysfunction.

Biology and therapeutic potential of cannabinoid CB2 receptor inverse agonists

Evidence has emerged suggesting a role for the cannabinoid CB2 receptor in immune cell motility. This provides a rationale for a novel and generalized immunoregulatory role for cannabinoid CB2 receptor-specific compounds. In support of this possibility, we will review the biology of a class of cannabinoid CB2 receptor-specific inverse agonist, the triaryl bis-sulfones. We will show that one candidate, Sch.414319, is potent and selective for the cannabinoid CB2 receptor, based on profiling studies using biochemical assays for 45 enzymes and 80 G-protein coupled receptors and ion channels. We will describe initial mechanistic studies using this optimized triaryl bis-sulfone, showing that the compound exerts a broad effect on cellular protein phosphorylations in human monocytes. This profile includes the down regulation of a required phosphorylation of the monocyte-specific actin bundling protein L-plastin. We suggest that this observation may provide a mechanism for the observed activity of Sch.414319 in vivo. Our continued analysis of the in vivo efficacy of this compound in diverse disease models shows that Sch.414319 is a potent modulator of immune cell mobility in vivo, can modulate bone damage in antigen-induced mono-articular arthritis in the rat, and is uniquely potent at blocking experimental autoimmune encephalomyelitis in the rat.

Genetic polymorphisms of the endocannabinoid system

Disturbances in the endocannabinoid system has been linked to diseases and conditions such as Parkinson's, schizophrenia, pain, energy metabolism, immune modulation, and bone density. Since the early 1990s, a number of genetic polymorphisms in the genes and proteins of the endocannabinoid system have been characterized. Currently identified genetic polymorphisms of the endocannabinoid system are reviewed here with particular consideration given to polymorphisms linked to drug and alcohol abuse, schizophrenia, other mental disorders, and energy metabolism.

The cannabinoid CB(2) receptor: a good friend in the gut

Mammalian tissues express the cannabinoid 1 (CB(1)) receptor and the cannabinoid 2 (CB(2)) receptor, the latter being involved in inflammation and pain. In somatic nerve pathways, the analgesic effects of CB(2) agonism are well documented. Two papers published in the Journal have provided evidence that CB(2) receptor activation inhibits visceral afferent nerve activity in rodents. These exciting findings are discussed in the context of recent data highlighting the emerging role of CB(2) receptor as a critical target able to counteract hypermotility in pathophysiological states, gut inflammation and possibly colon cancer.

Involvement of the 90-kDa Heat Shock Protein (Hsp-90) in CB2 Cannabinoid Receptor-Mediated Cell Migration: A New Role of Hsp-90 in Migration Signaling of a G Protein-Coupled Receptor

The endocannabinoid 2-arachidonoylglycerol (2-AG) enhances cell migration through the CB2 cannabinoid receptor. In this study, using an immunoprecipitation and mass spectrometry-based proteomic approach, we first identified the 90-kDa heat shock protein (Hsp90), a chaperone protein with novel signaling functions, as a CB2-interacting protein. The CB2/Hsp90 interaction was confirmed in human embryonic kidney 293 cells expressing transfected CB2 and in differentiated HL-60 cells expressing endogenous CB2, by coimmunoprecipitation and Western blot experiments, as well as by treatment with geldanamycin (GA), a specific Hsp90 inhibitor. Disruption of the CB2/Hsp90 interaction by treatment with GA or reducing Hsp90 levels with specific short interfering RNAs markedly inhibited 2-AG-induced cell migration, demonstrating that Hsp90 is crucial for 2-AG-induced cell migration. 2-AG treatment resulted in a CB2-mediated stimulation of Rac1 activity, and treatment with GA blocked 2AG-induced activation of Rac1. It is noteworthy that expression of the dominant-negative form of Rac1 reduced 2-AG-induced cell migration. These data demonstrate that 2-AG-induced activation of Rac1 is essential for 2-AG-induced cell migration, and the CB2/Hsp90 interaction is needed for 2-AG-induced activation of Rac1. Furthermore, 2-AG-induced Rac1 activation was sensitive to pertussis toxin treatment, hence involving G(i) proteins. In addition, treatment with GA significantly inhibited the CB2/Galpha(i2) interaction. As a whole, our data indicate that Hsp90 may serve as scaffold to keep the CB2 receptor and its signaling components, including Galpha(i2), in proximity, thus facilitating CB2-mediated signaling to cell migration through the G(i)-Rac1 pathway. By demonstrating that Hsp90 is essential for CB2-mediated signaling to cell migration, this study reveals a novel role of Hsp90 in the signaling events mediated by a G protein-coupled receptor.