The endocannabinoid system and its therapeutic exploitation in multiple sclerosis: Clues for other neuroinflammatory diseases

The next frontier in multiple sclerosis therapies: Current advances and evolving targets

Recent advancements in research have significantly enhanced our comprehension of the intricate immune components that contribute to multiple sclerosis (MS) pathogenesis. By conducting an in-depth analysis of complex molecular interactions involved in the immunological cascade of the disease, researchers have successfully identified novel therapeutic targets, leading to the development of innovative therapies. Leveraging pioneering technologies in proteomics, genomics, and the assessment of environmental factors has expedited our understanding of the vulnerability and impact of these factors on the progression of MS. Furthermore, these advances have facilitated the detection of significant biomarkers for evaluating disease activity. By integrating these findings, researchers can design novel molecules to identify new targets, paving the way for improved treatments and enhanced patient care. Our review presents recent discoveries regarding the pathogenesis of MS, highlights their genetic implications, and proposes an insightful approach for engaging with newer therapeutic targets in effectively managing this debilitating condition.

Comparative targeted lipidomics between serum and cerebrospinal fluid of multiple sclerosis patients shows sex and age-specific differences of endocannabinoids and glucocorticoids

Multiple sclerosis (MS) is a complex chronic neuroinflammatory disease characterized by demyelination leading to neuronal dysfunction and neurodegeneration manifested by various neurological impairments. The endocannabinoid system (ECS) is a lipid signalling network, which plays multiple roles in the central nervous system and the periphery, including synaptic signal transmission and modulation of inflammation. The ECS has been identified as a potential target for the development of novel therapeutic interventions in MS patients. It remains unclear whether ECS-associated metabolites are changed in MS and could serve as biomarkers in blood or cerebrospinal fluid (CSF). In this retrospective study we applied targeted lipidomics to matching CSF and serum samples of 74 MS and 80 non-neuroinflammatory control patients. We found that MS-associated lipidomic changes overall did not coincide between CSF and serum. While glucocorticoids correlated positively, only the endocannabinoid (eCB) 2-arachidonoyl glycerol (2-AG) showed a weak positive correlation (r = 0.3, p < 0.05) between CSF and serum. Peptide endocannabinoids could be quantified for the first time in CSF but did not differ between MS and controls. MS patients showed elevated levels of prostaglandin E2 and steaorylethanolamide in serum, and 2-oleoylglycerol and cortisol in CSF. Sex-specific differences were found in CSF of MS patients showing increased levels of 2-AG and glucocorticoids in males only. Overall, arachidonic acid was elevated in CSF of males. Interestingly, CSF eCBs correlated positively with age only in the control patients due to the increased levels of eCBs in young relapsing-remitting MS patients. Our findings reveal significant discrepancies between CSF and serum, underscoring that measuring eCBs in blood matrices is not optimal for detecting MS-associated changes in the central nervous system. The identified sex and age-specific changes of analytes of the stress axis and ECS specifically in the CSF of MS patients supports the role of the ECS in MS and may be relevant for drug development strategies.

Efficacy of cannabinoids compared to the current standard treatments on symptom relief in persons with multiple sclerosis (CANSEP trial): study protocol for a randomized clinical trial

Background

Multiple sclerosis (MS) is an inflammatory and degenerative disease of the central nervous system. More than 90,000 Canadians are affected; a cure is yet to be found. Available treatments to manage the disease course are only partially effective. For many years, persons with MS (PwMS) have used cannabis to relax, to reduce pain and spasticity, or to improve sleep and daily functioning, despite the lack of scientific evidence on the efficacy of specific cannabinoids [i.e., tetrahydrocannabinol (THC) and cannabidiol (CBD)] on these MS symptoms. The purpose of this clinical trial is to assess the effectiveness of different doses of these cannabinoids, alone or combined, on spasticity relief, compared to placebo. Moreover, we aim to determine which treatment is best effective to address other key MS conditions.

Methods

A double-blinded, randomized, factorial, placebo-controlled trial will be performed. We intend to include up to 250 PwMS aged over 21 recruited from the Centre hospitalier de l'Université de Montréal MS Clinic. PwMS will be randomly assigned on a 1:1:1:1 ratio to one of the trial arms: THC alone, CBD alone, THC/CBD combination, or placebo, using stratified blocked randomization, with random blocks within each stratum. The primary outcome is a self-assessment of spasticity using the mean Numeric Rating Scale score over 7 days. The main outcome will be the difference in this score at 4 weeks compared to baseline. Secondary outcomes include assessments of spasticity as measured by a clinician, pain, fatigue, sleep, bowel, bladder, and sexual dysfunction, restless legs syndrome, mental health, quality of life, mobility, cognitive functioning, and adverse events. Treatment responders are eligible for a 12-week extension phase, using the same treatment allocation and assessments.

Discussion

Previous clinical studies examined the efficacy of cannabis-based medicines in PwMS, mostly using products with 1:1 THC/CBD ratio. The major barrier to effectively use cannabis in real-world clinical settings is the lack of evidence on benefits of specific cannabinoids and information on possible related risks. The CANSEP study will contribute to overcome these limitations and identify the risks and benefits of cannabis-based treatments in PwMS.

Clinical trial registration

ClinicalTrials.Gov, NCT05092191.

Pharmacological blockade of 2-AG degradation ameliorates clinical, neuroinflammatory and synaptic alterations in experimental autoimmune encephalomyelitis

The endocannabinoid system (ECS) is critically involved in the pathophysiology of Multiple Sclerosis (MS), a neuroinflammatory and neurodegenerative disease of the central nervous system (CNS). Over the past decade, researchers have extensively studied the neuroprotective and anti-inflammatory effects of the ECS. Inhibiting the degradation of the endocannabinoid 2-arachidonoylglycerol (2-AG) has emerged as a promising strategy to mitigate brain damage in MS. In this study, we investigated the effects of a novel reversible MAGL inhibitor (MAGLi 432) on C57/BL6 female mice with experimental autoimmune encephalomyelitis (EAE), a model of MS. We assessed its implications on motor disability, neuroinflammation, and synaptic dysfunction. Systemic in vivo treatment with MAGLi 432 resulted in a less severe EAE disease, accompanied by increased 2-AG levels and decreased levels of arachidonic acid (AA) and prostaglandins (PGs) in the brain. Additionally, MAGLi 432 reduced both astrogliosis and microgliosis, as evidenced by decreased microglia/macrophage density and a less reactive morphology. Flow cytometry analysis further revealed fewer infiltrating CD45+ and CD3+ cells in the brains of MAGLi 432-treated EAE mice. Finally, MAGLi treatment counteracted the striatal synaptic hyperexcitability promoted by EAE neuroinflammation. In conclusion, MAGL inhibition significantly ameliorated EAE clinical disability and striatal inflammatory synaptopathy through potent anti-inflammatory effects. These findings provide new mechanistic insights into the neuroprotective role of the ECS during neuroinflammation and highlight the therapeutic potential of MAGLi-based drugs in mitigating MS-related inflammatory and neurodegenerative brain damage.

Synergism Between Hypothalamic Astrocytes and Neurons in Metabolic Control

Astrocytes are no longer considered as passive support cells. In the hypothalamus, these glial cells actively participate in the control of appetite, energy expenditure, and the processes leading to obesity and its secondary complications. Here we briefly review studies supporting this conclusion and the advances made in understanding the underlying mechanisms.

Exploring role of natural compounds in molecular alterations associated with brain ageing: A perspective towards nutrition for ageing brain

Aging refers to complete deterioration of physiological integrity and function. By midcentury, adults over 60 years of age and children under 15 years will begin to outnumber people in working age. This shift will bring multiple global challenges for economy, health, and society. Eventually, aging is a natural process playing a vital function in growth and development during pediatric stage, maturation during adult stage, and functional depletion. Tissues experience negative consequences with enhanced genomic instability, deregulated nutrient sensing, mitochondrial dysfunction, and decline in performance on cognitive tasks. As brain ages, its volume decreases, neurons & glia get inflamed, vasculature becomes less developed, blood pressure increases with a risk of stroke, ischemia, and cognitive deficits. Diminished cellular functions leads to progressive reduction in functional and emotional capacity with higher possibility of disease and finally death. This review overviews cellular as well as molecular aspects of aging, biological pathway related to accelerated brain aging, and strategies minimizing cognitive aging. Age-related changes include altered bioenergetics, decreased neuroplasticity and flexibility, aberrant neural activity, deregulated Ca2+ homeostasis in neurons, buildup of reactive oxygen species, and neuro-inflammation. Unprecedented progress has been achieved in recent studies, particularly in terms of how herbal or natural substances affect genetic pathways and biological functions that have been preserved through evolution. Herein, the present work provides an overview of ageing and age-related disorders and explore the molecular mechanisms that underlie therapeutic effects of herbal and natural chemicals on neuropathological signs of brain aging.

Selected cannabis cultivars modulate glial activation: in vitro and in vivo studies

INTRODUCTION

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system characterized by neuroinflammation, demyelination and axonal loss. Cannabis, an immunomodulating agent, is known for its ability to treat MS effectively. However, due to variations in the profile of secondary metabolites, especially cannabinoids, among cannabis cultivars, the effectiveness of cannabis treatment can vary, with significant variability in the effects on different biological parameters. For screening available cultivars, cellular in vitro as well as pre-clinical in vivo assays, are required to evaluate the effectiveness of the wide range of chemical variability that exists in cannabis cultivars. This study evaluated comparatively three chemically diverse cannabis cultivars, CN2, CN4 and CN6, containing different ratios of phytocannabinoids, for their neuroinflammatory activity in MS model.

MATERIALS AND METHODS

In vitro experiments were performed with lipopolysaccharide (LPS)-activated BV-2 microglia and primary glial cells to evaluate the effect of different cannabis cultivars on nitric oxide (NO) and inflammatory cytokines, as well as inducible nitric oxide synthase (iNOS) protein expression. An in vivo experiment using the experimental autoimmune encephalomyelitis (EAE) MS model was conducted using Myelin oligodendrocyte glycoprotein (MOG) as the activating peptide. The cannabis extracts of the cultivars CN2, CN4, CN6 or vehicle, were intraperitoneally injected with clinical scores given based on observed symptoms over the course of study. At the end of the experiment, the mice were sacrificed, and splenocyte cytokine secretion was measured using ELISA. Lumbar sections from the spinal cord of treated MS mice were evaluated for microglia, astrocytes and CD4+ cells.

RESULTS

Extracts of the CN2 cultivar contained tetrahydrocannabinolic acid (THCA) and tetrahydrocannabinol (THC) without cannabidiol (CBD), and a number of monoterpenes. CN4 contained cannabidiolic acid (CBDA) and tetrahydrocannabidiolic acid (THCA), with significant amounts of THC: CBD in a 1:1 ratio, as well as sesquiterpenes and some monoterpenes; and CN6 contained primarily CBDA and THCA, as well as THC and CBD in a 2:1 ratio, with some sesquiterpenes and no monoterpenes. All extracts were not cytotoxic in glial cells up to 50 µg/ml. Dose dependent inhibition of LPS-induced BV2 as well as primary microglial NO secretion confirmed the anti-inflammatory and anti-oxidative activity of the three cannabis cultivars. CN2 but not CN4 reduced both astrocytosis and microglial activation in lumbar sections of EAE mice. In contrast, CN4 but not CN2 significantly decreased the secretion of TNFα and Interferon γ (IFNγ) in primary splenocytes extracted from EAE mice.

CONCLUSIONS

While both cannabis cultivars, CN2 and CN4, significantly reduced the severity of the clinical signs throughout the course of the study, they modulated different inflammatory mediators and pathways, probably due to differences in their phytocannabinoid composition. This demonstrates the differential potential of cannabis cultivars differing in chemotype to regulate neuroinflammation and their potential to treat MS.

Pharmacokinetics and pharmacodynamics of cannabis-based medicine in a patient population included in a randomized, placebo-controlled, clinical trial

Information on the pharmacokinetics (PK) and pharmacodynamics (PD) of orally administered cannabis-based medicine (CBM) in capsule formulation in patient populations is sparse. In this exploratory study, we aimed to evaluate the PK and PD in a probable steady state of CBM in neuropathic pain and spasticity in a population of patients with multiple sclerosis (MS). Of 134 patients participating in a randomized, double-blinded, placebo-controlled, trial, 23 patients with MS (17 female) mean age 52 years (range 21-67) were enrolled in this substudy. They received oral capsules containing Δ9 -tetrahydrocannabinol (THC, n = 4), cannabidiol (CBD, n = 6), a combination (THC&CBD, n = 4), or placebo (n = 9). Maximum doses were 22.5 mg (THC) and 45 mg (CBD) a day divided into three administrations. PD parameters were evaluated for pain and spasticity. Blood samples were analyzed using an ultra-high-performance liquid chromatography-tandem mass spectrometer after protein precipitation and phospholipid removal. PK parameters were estimated using computerized modeling. The variation in daily dose and PK between individuals was considerable in a steady state, yet comparable with previous reports from healthy controls. Based on a simulation of the best model, the estimated PK parameters (mean) for THC (5 mg) were Cmax 1.21 ng/mL, Tmax 2.68 h, and half-life 2.75 h, and for CBD (10 mg) were Cmax 2.67 ng/mL, Tmax 0.10 h, and half-life 4.95 h, respectively. No effect was found on the PD parameters, but the placebo response was considerable. More immediate adverse events were registered in the active treatment groups compared with the placebo group.

Phytocannabinoids: Pharmacological effects, biomedical applications, and worldwide prospection

Scientific evidence exists about the association between neurological diseases (i.e., Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis (ALS), multiple sclerosis, depression, and memory loss) and oxidative damage. The increasing worldwide incidence of such diseases is attracting the attention of researchers to find palliative medications to reduce the symptoms and promote quality of life, in particular, in developing countries, e.g., South America and Africa. Among potential alternatives, extracts of Cannabis Sativa L. are suitable for people who have neurological disorders, spasticity, and pain, nausea, resulting from diseases such as cancer and arthritis. In this review, we discuss the latest developments in the use of Cannabis, its subtypes and constituents, extraction methods, and relevant pharmacological effects. Biomedical applications, marketed products, and prospects for the worldwide use of Cannabis Sativa L. extracts are also discussed, providing the bibliometric maps of scientific literature published in representative countries from South America (i.e., Brazil) and Africa (i.e., South Africa). A lack of evidence on the effectiveness and safety of Cannabis, besides the concerns about addiction and other adverse events, has led many countries to act with caution before changing Cannabis-related regulations. Recent findings are expected to increase the social acceptance of Cannabis, while new technologies seem to boost the global cannabis market because the benefits of (-)-trans-delta-9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD) use have been proven in several studies in addition to the potential to general new employment.

Unleashing nature's potential and limitations: Exploring molecular targeted pathways and safe alternatives for the treatment of multiple sclerosis (Review)

Driven by the limitations and obstacles of the available approaches and medications for multiple sclerosis (MS) that still cannot treat the disease, but only aid in accelerating the recovery from its attacks, the use of naturally occurring molecules as a potentially safe and effective treatment for MS is being explored in model organisms. MS is a devastating disease involving the brain and spinal cord, and its symptoms vary widely. Multiple molecular pathways are involved in the pathogenesis of the disease. The present review showcases the recent advancements in harnessing nature's resources to combat MS. By deciphering the molecular pathways involved in the pathogenesis of the disease, a wealth of potential therapeutic agents is uncovered that may revolutionize the treatment of MS. Thus, a new hope can be envisioned in the future, aiming at paving the way toward identifying novel safe alternatives to improve the lives of patients with MS.

Integration of plasma and CSF metabolomics with CSF proteomic reveals novel associations between lipid mediators and central nervous system vascular and energy metabolism

Integration of the omics data, including metabolomics and proteomics, provides a unique opportunity to search for new associations within metabolic disorders, including Alzheimer's disease. Using metabolomics, we have previously profiled oxylipins, endocannabinoids, bile acids, and steroids in 293 CSF and 202 matched plasma samples from AD cases and healthy controls and identified both central and peripheral markers of AD pathology within inflammation-regulating cytochrome p450/soluble epoxide hydrolase pathway. Additionally, using proteomics, we have identified five cerebrospinal fluid protein panels, involved in the regulation of energy metabolism, vasculature, myelin/oligodendrocyte, glia/inflammation, and synapses/neurons, affected in AD, and reflective of AD-related changes in the brain. In the current manuscript, using metabolomics-proteomics data integration, we describe new associations between peripheral and central lipid mediators, with the above-described CSF protein panels. Particularly strong associations were observed between cytochrome p450/soluble epoxide hydrolase metabolites, bile acids, and proteins involved in glycolysis, blood coagulation, and vascular inflammation and the regulators of extracellular matrix. Those metabolic associations were not observed at the gene-co-expression level in the central nervous system. In summary, this manuscript provides new information regarding Alzheimer's disease, linking both central and peripheral metabolism, and illustrates the necessity for the "omics" data integration to uncover associations beyond gene co-expression.

Cannabis-Based Medicine for Neuropathic Pain and Spasticity-A Multicenter, Randomized, Double-Blinded, Placebo-Controlled Trial

Patients with multiple sclerosis (MS) and spinal cord injury (SCI) commonly sustain central neuropathic pain (NP) and spasticity. Despite a lack of consistent evidence, cannabis-based medicine (CBM) has been suggested as a supplement treatment. We aimed to investigate the effect of CBM on NP and spasticity in patients with MS or SCI. We performed a randomized, double-blinded, placebo-controlled trial in Denmark. Patients aged ≥18 years with NP (intensity >3, ≤9 on a numerical rating scale (NRS0-10) and/or spasticity (>3 on NRS0-10) were randomized to treatment consisting of either delta-9-tetrahydrocannabinol (THC), cannabidiol (CBD), a combination of THC&CBD in maximum doses of 22.5 mg, 45 mg and 22.5/45 mg per day, respectively, or placebo. A baseline registration was performed before randomization. Treatment duration was six weeks followed by a one-week phaseout. Primary endpoints were the intensity of patient-reported NP and/or spasticity. Between February 2019 and December 2021, 134 patients were randomized (MS n = 119, SCI n = 15), where 32 were assigned to THC, 31 to CBD, 31 to THC&CBD, and 40 to placebo. No significant difference was found for: mean pain intensity (THC 0.42 (-0.54-1.38), CBD 0.45 (-0.47-1.38) and THC&CBD 0.16 (-0.75-1.08)), mean spasticity intensity (THC 0.24 (-0.67-1.45), CBD 0.46 (-0.74-1.65), and THC&CBD 0.10 (-1.18-1.39), secondary outcomes (patient global impression of change and quality of life), or any tertiary outcomes. We aimed to include 448 patients in the trial; however, due to COVID-19 and recruitment challenges, fewer were included. Nevertheless, in this four-arm parallel trial, no effect was found between placebo and active treatment with THC or CBD alone or in combination on NP or spasticity in patients with either MS or SCI. The trial was registered with the EU Clinical Trials Register EudraCT (2018-002315-98).

Women are Taking the Hit: Examining the Unique Consequences of Cannabis Use Across the Female Lifespan

Cannabis use has risen dramatically in recent years due to global decriminalization and a resurgence in the interest of potential therapeutic benefits. While emerging research is shaping our understanding of the benefits and harms of cannabis, there remains a paucity of data specifically focused on how cannabis affects the female population. The female experience of cannabis use is unique, both in the societal context and because of the biological ramifications. This is increasingly important given the rise in cannabis potency, as well as the implications this has for the prevalence of Cannabis Use Disorder (CUD). Therefore, this scoping review aims to discuss the prevalence of cannabis use and CUD in women throughout their lifespan and provide a balanced prospective on the positive and negative consequences of cannabis use. In doing so, this review will highlight the necessity for continued research that goes beyond sex differences.

Inhibiting degradation of 2-arachidonoylglycerol as a therapeutic strategy for neurodegenerative diseases

Endocannabinoids are endogenous lipid signaling mediators that participate in a variety of physiological and pathological processes. 2-Arachidonoylglycerol (2-AG) is the most abundant endocannabinoid and is a full agonist of G-protein-coupled cannabinoid receptors (CB1R and CB2R), which are targets of Δ⁹-tetrahydrocannabinol (Δ⁹-THC), the main psychoactive ingredient in cannabis. While 2-AG has been well recognized as a retrograde messenger modulating synaptic transmission and plasticity at both inhibitory GABAergic and excitatory glutamatergic synapses in the brain, growing evidence suggests that 2-AG also functions as an endogenous terminator of neuroinflammation in response to harmful insults, thus maintaining brain homeostasis. Monoacylglycerol lipase (MAGL) is the key enzyme that degrades 2-AG in the brain. The immediate metabolite of 2-AG is arachidonic acid (AA), a precursor of prostaglandins (PGs) and leukotrienes. Several lines of evidence indicate that pharmacological or genetic inactivation of MAGL, which boosts 2-AG levels and reduces its hydrolytic metabolites, resolves neuroinflammation, mitigates neuropathology, and improves synaptic and cognitive functions in animal models of neurodegenerative diseases, including Alzheimer's disease (AD), multiple sclerosis (MS), Parkinson's disease (PD), and traumatic brain injury (TBI)-induced neurodegenerative disease. Thus, it has been proposed that MAGL is a potential therapeutic target for treatment of neurodegenerative diseases. As the main enzyme hydrolyzing 2-AG, several MAGL inhibitors have been identified and developed. However, our understanding of the mechanisms by which inactivation of MAGL produces neuroprotective effects in neurodegenerative diseases remains limited. A recent finding that inhibition of 2-AG metabolism in astrocytes, but not in neurons, protects the brain from TBI-induced neuropathology might shed some light on this unsolved issue. This review provides an overview of MAGL as a potential therapeutic target for neurodegenerative diseases and discusses possible mechanisms underlying the neuroprotective effects of restraining degradation of 2-AG in the brain.

Endocannabinoid signaling in brain diseases: Emerging relevance of glial cells

The discovery of cannabinoid receptors as the primary molecular targets of psychotropic cannabinoid Δ⁹ -tetrahydrocannabinol (Δ⁹ -THC) in late 1980s paved the way for investigations on the effects of cannabis-based therapeutics in brain pathology. Ever since, a wealth of results obtained from studies on human tissue samples and animal models have highlighted a promising therapeutic potential of cannabinoids and endocannabinoids in a variety of neurological disorders. However, clinical success has been limited and major questions concerning endocannabinoid signaling need to be satisfactorily addressed, particularly with regard to their role as modulators of glial cells in neurodegenerative diseases. Indeed, recent studies have brought into the limelight diverse, often unexpected functions of astrocytes, oligodendrocytes, and microglia in brain injury and disease, thus providing scientific basis for targeting glial cells to treat brain disorders. This Review summarizes the current knowledge on the molecular and cellular hallmarks of endocannabinoid signaling in glial cells and its clinical relevance in neurodegenerative and chronic inflammatory disorders.

Oxygenation of Anandamide by Lipoxygenases

The endocannabinoids anandamide and 2-arachidonoylglycerol are not only metabolized by serine hydrolases, such as fatty acid amide hydrolase, monoacylglycerol lipase, and α,β-hydrolases 6 and 12, but they also serve as substrates for cyclooxygenases, cytochrome P450s, and lipoxygenases. These enzymes oxygenate the 1Z,4Z-pentadiene system of the arachidonic acid backbone of endocannabinoids, thereby giving rise to an entirely new array of bioactive lipids. Hereby, a protocol is provided for the enzymatic synthesis, purification, and characterization of various oxygenated metabolites of anandamide generated by lipoxygenases, which enables the biological study and detection of these metabolites.

Role of integrating cannabinoids and the endocannabinoid system in neonatal hypoxic-ischaemic encephalopathy

Neonatal hypoxic-ischaemic events, which can result in long-term neurological impairments or even cell death, are among the most significant causes of brain injury during neurodevelopment. The complexity of neonatal hypoxic-ischaemic pathophysiology and cellular pathways make it difficult to treat brain damage; hence, the development of new neuroprotective medicines is of great interest. Recently, numerous neuroprotective medicines have been developed to treat brain injuries and improve long-term outcomes based on comprehensive knowledge of the mechanisms that underlie neuronal plasticity following hypoxic-ischaemic brain injury. In this context, understanding of the medicinal potential of cannabinoids and the endocannabinoid system has recently increased. The endocannabinoid system plays a vital neuromodulatory role in numerous brain regions, ensuring appropriate control of neuronal activity. Its natural neuroprotection against adult brain injury or acute brain injury also clearly demonstrate the role of endocannabinoid signalling in modulating neuronal activity in the adult brain. The goal of this review is to examine how cannabinoid-derived compounds can be used to treat neonatal hypoxic-ischaemic brain injury and to assess the critical function of the endocannabinoid system and its potential for use as a new neuroprotective treatment for neonatal hypoxic-ischaemic brain injury.

Anandamide and other N-acylethanolamines: A class of signaling lipids with therapeutic opportunities

N-acylethanolamines (NAEs), including N-palmitoylethanolamine (PEA), N-oleoylethanolamine (OEA), N-arachidonoylethanolamine (AEA, anandamide), N-docosahexaenoylethanolamine (DHEA, synaptamide) and their oxygenated metabolites are a lipid messenger family with numerous functions in health and disease, including inflammation, anxiety and energy metabolism. The NAEs exert their signaling role through activation of various G protein-coupled receptors (cannabinoid CB₁ and CB₂ receptors, GPR55, GPR110, GPR119), ion channels (TRPV1) and nuclear receptors (PPAR-α and PPAR-γ) in the brain and periphery. The biological role of the oxygenated NAEs, such as prostamides, hydroxylated anandamide and DHEA derivatives, are less studied. Evidence is accumulating that NAEs and their oxidative metabolites may be aberrantly regulated or are associated with disease severity in obesity, metabolic syndrome, cancer, neuroinflammation and liver cirrhosis. Here, we comprehensively review NAE biosynthesis and degradation, their metabolism by lipoxygenases, cyclooxygenases and cytochrome P450s and the biological functions of these signaling lipids. We discuss the latest findings and therapeutic potential of modulating endogenous NAE levels by inhibition of their degradation, which is currently under clinical evaluation for neuropsychiatric disorders. We also highlight NAE biosynthesis inhibition as an emerging topic with therapeutic opportunities in endocannabinoid and NAE signaling.

Electrophysiology of Endocannabinoid Signaling

Electrophysiological technique is an efficient tool for investigating the synaptic regulatory effects mediated by the endocannabinoid system. Stimulation of presynaptic type 1 cannabinoid receptor (CB1) is the principal mode by which endocannabinoids suppress transmitter release in the central nervous system, but a non-retrograde manner of functioning and other receptors have also been described. Endocannabinoids are key modulators of both short- and long-term plasticity. Here, we discuss ex vivo electrophysiological approaches to examine synaptic signaling induced by cannabinoid and endocannabinoid molecules in the mammalian brain.

Cannabinoid receptor-2 attenuates neuroinflammation by promoting autophagy-mediated degradation of the NLRP3 inflammasome post spinal cord injury

Background

Neuroinflammation following spinal cord injury (SCI) results in prolonged neurological damage and locomotor dysfunction. Polarization of microglia is vital to regulation of neuroinflammation, although the underlying mechanisms have not yet been elucidated. Endocannabinoid receptor subtype 2 (CB2R) is reported to ameliorate neurodegeneration via immunomodulation activities. However, the underlying machinery in the context of SCI remains unclear.

Methods

A lipopolysaccharide-induced microglia inflammation model and a mouse model of SCI were employed to investigate the regulatory role of CB2R in the polarization of microglia in response to excess neuroinflammation. Markers of inflammation and autophagy were measured by Western blot analysis, immunofluorescence, flow cytometry, and enzyme-linked immunosorbent assays. Histological staining with hematoxylin and eosin, Nissl, and Luxol^® fast blue was conducted using commercial kits. The locomotor function of the hindlimbs of the experimental mice was evaluated with the Basso Mouse Scale, Louisville Swim Scale, and footprint assay.

Results

The results showed that CB2R promoted M2 differentiation, increased interleukin (IL)-10 expression, and inhibited M1 differentiation with decreased expression of IL-1β and IL-6. CB2R activation also increased ubiquitination of the NLRP3 inflammasome and interacted with the autophagy-related proteins p62 and microtubule-associated proteins 1B light chain 3. Treatment with the CB2R activator JWH-133 reduced loss of myelin, apoptosis of neurons, and glial scarring, leading to improved functional recovery of the hindlimbs, while the CB2R antagonist AM630 produced opposite results.

Conclusion

Taken together, these results suggested that CB2R activation attenuated neuroinflammation targeting microglial polarization by promoting NLRP3 clearance, thereby facilitating functional recovery post-SCI.

Cannabinoid receptors in the inflammatory cells of canine atopic dermatitis

Background

Atopic dermatitis (AD) is one of the most common cutaneous inflammatory and pruritic diseases in dogs. Considering its multifactorial nature, AD can be a challenging disease to manage, and the therapeutic strategy must often be multimodal. In recent years, research has been moving toward the use of natural products which have beneficial effects on inflammation and itching, and no side effects. Cannabinoid receptors have been demonstrated to be expressed in healthy and diseased skin; therefore, one of the potential alternative therapeutic targets for investigating AD is the endocannabinoid system (ECS).

Objective

To immunohistochemically investigate the expression of the cannabinoid receptor type 2 (CB2R), and the cannabinoid-related receptors G protein-coupled receptor 55 (GPR55), transient receptor potential vanilloid 1 (TRPV1) and ankyrin 1 (TRPA1) in mast cells (MCs), macrophages, dendritic cells (DCs), T cells, and neutrophils of the skin of dogs with AD.

Animals

Samples of skin tissues were collected from eight dogs with AD (AD-dogs).

Materials and methods

The immunofluorescent stained cryosections of the skins of 8 dogs with AD having antibodies against CB2R, GPR55, TRPV1, TRPA1 were semiquantitatively evaluated. The inflammatory cells were identified using antibodies against tryptase (mast cells), ionized calcium binding adaptor molecule 1 (IBA1) (macrophages/DCs), CD3 (T cells), and calprotectin (neutrophils). The proportions of MCs, macrophages/DCs, T cells, and neutrophils expressing CB2R, GPR55, TRPV1 and TRPA1 were evaluated.

Results

The cells of the inflammatory infiltrate showed immunoreactivity (IR) for all or for some of the cannabinoid and cannabinoid-related receptors studied. In particular, MCs and macrophages/DCs showed CB2R-, GPR55-, TRPA1-, and TRPV1-IR; T cells showed CB2R-, GPR55- and TRPA1-IR, and neutrophils expressed GPR55-IR. Co-localization studies indicated that CB2R-IR was co-expressed with TRPV1-, TRPA1-, and GPR55-IR in different cellular elements of the dermis of the AD-dogs.

Conclusions and clinical importance

Cannabinoid receptor 2, and cannabinoid-related receptors GPR55, TRPV1 and TRPA1 were widely expressed in the inflammatory infiltrate of the AD-dogs. Based on the present findings, the ECS could be considered to be a potential therapeutic target for dogs with AD, and may mitigate itch and inflammation.

Cannabinoids: Therapeutic Use in Clinical Practice

Medical case reports suggest that cannabinoids extracted from Cannabis sativa have therapeutic effects; however, the therapeutic employment is limited due to the psychotropic effect of its major component, Δ9-tetrahydrocannabinol (THC). The new scientific discoveries related to the endocannabinoid system, including new receptors, ligands, and mediators, allowed the development of new therapeutic targets for the treatment of several pathological disorders minimizing the undesirable psychotropic effects of some constituents of this plant. Today, FDA-approved drugs, such as nabiximols (a mixture of THC and non-psychoactive cannabidiol (CBD)), are employed in alleviating pain and spasticity in multiple sclerosis. Dronabinol and nabilone are used for the treatment of chemotherapy-induced nausea and vomiting in cancer patients. Dronabinol was approved for the treatment of anorexia in patients with AIDS (acquired immune deficiency syndrome). In this review, we highlighted the potential therapeutic efficacy of natural and synthetic cannabinoids and their clinical relevance in cancer, neurodegenerative and dermatological diseases, and viral infections.

Interaction between endocannabinoids and the adrenergic system before and after stress-exposure

Cold stress-induced analgesia (c-SIA) has been evaluated in male Wistar rats injected with cannabinoid receptors type 1 and a2-adrenergic receptor agonists and antagonists in different combinations before or after stress exposure.

The aim of the study was to evaluate whether the endogenous cannabinoid and the adrenergic systems influenced c-SIA, and the patterns of their potential interaction.

Exogenous administration of anandamide and Clonidine together, before or after stress exposure, increased c-SIA even with differences in the time of manifestation of the effect, its duration and the degree.

The two systems differently contribute to c-SIA pathogenesis and mediation. Administered before stress exposure cannabinoids and the adrenergic system seem to oppose each other: the latter rather potentiates, while cannabinoids suppress c-SIA. Administered after stress exposure, instead, the two systems appear to exert a synergistic effect, and antagonization of each one of them abolishes the analgesic effect.

Endocannabinoid Modulation in Neurodegenerative Diseases: In Pursuit of Certainty

Simple Summary

Neurodegenerative diseases represent an important cause of morbidity and mortality worldwide. Existing therapeutic options are limited and focus mostly on improving symptoms and reducing exacerbations. The endocannabinoid system is involved in the pathophysiology of such disorders, an idea which has been highlighted by recent scientific work. The current work focusses its attention on the importance and implications of this system and its synthetic and natural ligands in disorders such as Alzheimer’s, Parkinson’s, Huntington’s and multiple sclerosis.

Abstract

Neurodegenerative diseases are an increasing cause of global morbidity and mortality. They occur in the central nervous system (CNS) and lead to functional and mental impairment due to loss of neurons. Recent evidence highlights the link between neurodegenerative and inflammatory diseases of the CNS. These are typically associated with several neurological disorders. These diseases have fundamental differences regarding their underlying physiology and clinical manifestations, although there are aspects that overlap. The endocannabinoid system (ECS) is comprised of receptors (type-1 (CB1R) and type-2 (CB2R) cannabinoid-receptors, as well as transient receptor potential vanilloid 1 (TRPV1)), endogenous ligands and enzymes that synthesize and degrade endocannabinoids (ECBs). Recent studies revealed the involvement of the ECS in different pathological aspects of these neurodegenerative disorders. The present review will explore the roles of cannabinoid receptors (CBRs) and pharmacological agents that modulate CBRs or ECS activity with reference to Alzheimer’s Disease (AD), Parkinson’s Disease (PD), Huntington’s Disease (HD) and multiple sclerosis (MS).

Neurological Benefits, Clinical Challenges, and Neuropathologic Promise of Medical Marijuana: A Systematic Review of Cannabinoid Effects in Multiple Sclerosis and Experimental Models of Demyelination

Despite current therapeutic strategies for immunomodulation and relief of symptoms in multiple sclerosis (MS), remyelination falls short due to dynamic neuropathologic deterioration and relapses, leading to accrual of disability and associated patient dissatisfaction. The potential of cannabinoids includes add-on immunosuppressive, analgesic, neuroprotective, and remyelinative effects. This study evaluates the efficacy of medical marijuana in MS and its experimental animal models. A systematic review was conducted by a literature search through PubMed, ProQuest, and EBSCO electronic databases for studies reported since 2007 on the use of cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC) in MS and in experimental autoimmune encephalomyelitis (EAE), Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD), and toxin-induced demyelination models. Study selection and data extraction were performed by 3 reviewers, and 28 studies were selected for inclusion. The certainty of evidence was appraised using the Cochrane GRADE approach. In clinical studies, there was low- and moderate-quality evidence that treatment with ~1:1 CBD/THC mixtures as a nabiximols (Sativex®) oromucosal spray reduced numerical rating scale (NRS) scores for spasticity, pain, and sleep disturbance, diminished bladder overactivity, and decreased proinflammatory cytokine and transcription factor expression levels. Preclinical studies demonstrated decreases in disease severity, hindlimb stiffness, motor function, neuroinflammation, and demyelination. Other experimental systems showed the capacity of cannabinoids to promote remyelination in vitro and by electron microscopy. Modest short-term benefits were realized in MS responders to adjunctive therapy with CBD/THC mixtures. Future studies are recommended to investigate the cellular and molecular mechanisms of cannabinoid effects on MS lesions and to evaluate whether medical marijuana can accelerate remyelination and retard the accrual of disability over the long term.

Cannabinoid and endocannabinoid system: a promising therapeutic intervention for multiple sclerosis

Multiple sclerosis (MS) is a chronic and complex neurodegenerative disease, distinguished by the presence of lesions in the central nervous system (CNS) due to exacerbated immunological responses that inflict oligodendrocytes and the myelin sheath of axons. In recent years, studies have focused on targeted therapeutics for MS that emphasize the role of G protein-coupled receptors (GPCRs), specifically cannabinoids receptors. Clinical studies have suggested the therapeutic potential of cannabinoids derived from Cannabis sativa in relieving pain, tremors and spasticity. Cannabinoids also appear to prevent exaggerated immune responses in CNS due to compromised blood-brain barrier. Both, endocannabinoid system (ECS) modulators and cannabinoid ligands actively promote oligodendrocyte survival by regulating signaling, migration and myelination of nerve cells. The cannabinoid receptors 1 (CB1) and 2 (CB2) of ECS are the main ones in focus for therapeutic intervention of MS. Various CB1/CB2 receptors agonists have been experimentally studied which showed anti-inflammatory properties and are considered to be effective as potential therapeutics for MS. In this review, we focused on the exacerbated immune attack on nerve cells and the role of the cannabinoids and its interaction with the ECS in CNS during MS pathology.

Inflammaging and Cannabinoids

Aging is a complex phenomenon associated with a wide spectrum of physical and physiological changes affecting every part of all metazoans, if they escape death prior to reaching maturity. Critical to survival, the immune system evolved as the principal component of response to injury and defense against pathogen invasions. Because how significantly immune system affects and is affected by aging, several neologisms now appear to encapsulate these reciprocal relationships, such as Immunosenescence. The central part of Immunosenescence is Inflammaging -a sustained, low-grade, sterile inflammation occurring after reaching reproductive prime. Once initiated, the impact of Inflammaging and its adverse effects determine the direction and magnitudes of further Inflammaging. In this article, we review the nature of this vicious cycle, we will propose that phytocannabinoids as immune regulators may possess the potential as effective adjunctive therapies to slow and, in certain cases, reverse the pathologic senescence to permit a more healthy aging.

Potentiation of microglial endocannabinoid signaling alleviates neuroinflammation in Alzheimer's disease

Alzheimer's disease (AD) isaprogressive neurodegenerative disorder characterized by chronic inflammation due to the presence of neurotoxic Aβ and tau proteins. Increased microglial activation and inflated immune response are the other factors to be considered in AD pathology. Microglial cells own biochemical machinery that synthesizes and release endocannabinoids. The exploitation of therapeutic actions of endocannabinoid system has newly emerged in the field of Alzheimer's disease. The activation of cannabinoid receptors/ cannabinoid system modulates inflammatory responses. This review assesses the association between the microglial endocannabinoid system and neuroinflammation in AD. The data supporting the anti-inflammatory role of pharmacological agents modulating cannabinoid system are also reviewed.

Cannabinoid Drugs-Related Neuroprotection as a Potential Therapeutic Tool Against Chemotherapy-Induced Cognitive Impairment

In recent years, and particularly associated with the increase of cancer patients’ life expectancy, the occurrence of cancer treatment sequelae, including cognitive impairments, has received considerable attention. Chemotherapy-induced cognitive impairments (CICI) can be observed not only during pharmacological treatment of the disease but also long after cessation of this therapy. The lack of effective tools for its diagnosis together with the limited treatments currently available for alleviation of the side-effects induced by chemotherapeutic agents, demonstrates the need of a better understanding of the mechanisms underlying the pathology. This review focuses on the comprehensive appraisal of two main processes associated with the development of CICI: neuroinflammation and oxidative stress, and proposes the endogenous cannabinoid system (ECS) as a new therapeutic target against CICI. The neuroprotective role of the ECS, well described in other cognitive-related neuropathologies, seems to be able to reduce the activation of pro-inflammatory cytokines involved in the neuroinflammatory supraspinal processes underlying CICI. This review also provides evidence supporting the role of cannabinoid-based drugs in the modulation of oxidative stress processes that underpin cognitive impairments, and warrant the investigation of endocannabinoid components, still unknown, that may mediate the molecular mechanism behind this neuroprotective activity. Finally, this review points forward the urgent need of research focused on the understanding of CICI and the investigation of new therapeutic targets.

Inhibition of N-acylethanolamine-hydrolyzing acid amidase reduces T cell infiltration in a mouse model of multiple sclerosis

Experimental autoimmune encephalomyelitis (EAE) is an animal model of multiple sclerosis (MS), in which myeloid cells sustain inflammation, take part in priming, differentiation, and reactivation of myelin-specific T cells, and cause direct myelin damage. N-Acylethanolamine-hydrolyzing acid amidase (NAAA) is a proinflammatory enzyme induced by phlogosis and overexpressed in macrophages and microglia of EAE mice. Targeting these cell populations by inhibiting NAAA may be a promising pharmacological strategy to modulate the inflammatory aspect of MS and manage disease progression. To address this goal, we used ARN16186, a small molecule specifically designed and synthesized as a pharmacological tool to inhibit NAAA. We assessed whether enzyme inhibition affected the severity of neurological symptoms and modulated immune cell infiltration into the central nervous system of EAE mice. We found that preventive chronic treatment with ARN16186 was efficacious in slowing disease progression and preserving locomotor activity in EAE mice. Furthermore, NAAA inhibition reduced the number of immune cells infiltrating the spinal cord and modulated the overactivation of NF-kB and STAT3 transcription factors, leading to less expansion of Th17 cells over the course of the disease.

A Proteomic View of Cellular and Molecular Effects of Cannabis

Cannabis (Cannabis sativa), popularly known as marijuana, is the most commonly used psychoactive substance and is considered illicit in most countries worldwide. However, a growing body of research has provided evidence of the therapeutic properties of chemical components of cannabis known as cannabinoids against several diseases including Alzheimer's disease (AD), multiple sclerosis (MS), Parkinson's disease, schizophrenia and glaucoma; these have prompted changes in medicinal cannabis legislation. The relaxation of legal restrictions and increased socio-cultural acceptance has led to its increase in both medicinal and recreational usage. Several biochemically active components of cannabis have a range of effects on the biological system. There is an urgent need for more research to better understand the molecular and biochemical effects of cannabis at a cellular level, to understand fully its implications as a pharmaceutical drug. Proteomics technology is an efficient tool to rigorously elucidate the mechanistic effects of cannabis on the human body in a cell and tissue-specific manner, drawing conclusions associated with its toxicity as well as therapeutic benefits, safety and efficacy profiles. This review provides a comprehensive overview of both in vitro and in vivo proteomic studies involving the cellular and molecular effects of cannabis and cannabis-derived compounds.

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.

Association of plasma and CSF cytochrome P450, soluble epoxide hydrolase, and ethanolamide metabolism with Alzheimer's disease

BACKGROUND

Alzheimer's disease, cardiovascular disease, and other cardiometabolic disorders may share inflammatory origins. Lipid mediators, including oxylipins, endocannabinoids, bile acids, and steroids, regulate inflammation, energy metabolism, and cell proliferation with well-established involvement in cardiometabolic diseases. However, their role in Alzheimer's disease is poorly understood. Here, we describe the analysis of plasma and cerebrospinal fluid lipid mediators in a case-control comparison of ~150 individuals with Alzheimer's disease and ~135 healthy controls, to investigate this knowledge gap.

METHODS

Lipid mediators were measured using targeted quantitative mass spectrometry. Data were analyzed using the analysis of covariates, adjusting for sex, age, and ethnicity. Partial least square discriminant analysis identified plasma and cerebrospinal fluid lipid mediator discriminates of Alzheimer's disease. Alzheimer's disease predictive models were constructed using machine learning combined with stepwise logistic regression.

RESULTS

In both plasma and cerebrospinal fluid, individuals with Alzheimer's disease had elevated cytochrome P450/soluble epoxide hydrolase pathway components and decreased fatty acid ethanolamides compared to healthy controls. Circulating metabolites of soluble epoxide hydrolase and ethanolamides provide Alzheimer's disease predictors with areas under receiver operator characteristic curves ranging from 0.82 to 0.92 for cerebrospinal fluid and plasma metabolites, respectively.

CONCLUSIONS

Previous studies report Alzheimer's disease-associated soluble epoxide hydrolase upregulation in the brain and that endocannabinoid metabolism provides an adaptive response to neuroinflammation. This study supports the involvement of P450-dependent and endocannabinoid metabolism in Alzheimer's disease. The results further suggest that combined pharmacological intervention targeting both metabolic pathways may have therapeutic benefits for Alzheimer's disease.

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.

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.

Functional Fine-Tuning of Metabolic Pathways by the Endocannabinoid System-Implications for Health and Disease

The endocannabinoid system (ECS) employs a huge network of molecules (receptors, ligands, and enzymatic machinery molecules) whose interactions with other cellular networks have still not been fully elucidated. Endogenous cannabinoids are molecules with the primary function of control of multiple metabolic pathways. Maintenance of tissue and cellular homeostasis by functional fine-tuning of essential metabolic pathways is one of the key characteristics of the ECS. It is implicated in a variety of physiological and pathological states and an attractive pharmacological target yet to reach its full potential. This review will focus on the involvement of ECS in glucose and lipid metabolism, food intake regulation, immune homeostasis, respiratory health, inflammation, cancer and other physiological and pathological states will be substantiated using freely available data from open-access databases, experimental data and literature review. Future directions should envision capturing its diversity and exploiting pharmacological options beyond the classical ECS suspects (exogenous cannabinoids and cannabinoid receptor monomers) as signaling through cannabinoid receptor heteromers offers new possibilities for different biochemical outcomes in the cell.

Selective Endocannabinoid Reuptake Inhibitor WOBE437 Reduces Disease Progression in a Mouse Model of Multiple Sclerosis

The modulation of the endocannabinoid system (ECS) has shown positive results in animal models of multiple sclerosis (MS) and immune and inflammatory disorders. However, chronic administration of CB1 receptor agonists and degrading enzyme inhibitors can lead to CB1 receptor desensitization and sedation. WOBE437 is the prototype of a new class of ECS modulators named selective endocannabinoid reuptake inhibitors (SERIs), which mildly and selectively increase central endocannabinoid levels with a self-limiting mode of action. In previous studies, WOBE437 demonstrated analgesic, anxiolytic, and anti-inflammatory effects. Here, we tested the therapeutic potential of WOBE437 in a clinically relevant mouse model of MS (experimental autoimmune encephalomyelitis). C57BL/6 mice were administered WOBE437 (10 mg/kg, 20 days) or vehicle using two therapeutic options: (1) starting the treatment at the disease onset or (2) before reaching the peak of the disease. In both strategies, WOBE437 significantly reduced disease severity and accelerated recovery through CB1 and CB2 receptor-dependent mechanisms. At the peak of the disease, WOBE437 increased endocannabinoid levels in the cerebellum, concurring with a reduction of central nervous system (CNS)-infiltrating immune cells and lower microglial proliferation. At the end of treatment, endocannabinoid levels were mildly increased in brain, cerebellum, and plasma of WOBE437-treated mice, without desensitization of CB1 receptor in the brain and cerebellum. In a mouse model of spasticity (Straub test), WOBE437 (10 mg/kg) induced significant muscle relaxation without eliciting the typical sedative effects associated with muscle relaxants or CB1 receptor agonists. Collectively, our results show that WOBE437 (and SERIs) may represent a novel therapeutic strategy for slowing MS progression and control major symptoms.

Anti-Inflammatory Effects of Fatty Acid Amide Hydrolase Inhibition in Monocytes/Macrophages from Alzheimer's Disease Patients

Growing evidence shows that the immune system is critically involved in Alzheimer’s disease (AD) pathogenesis and progression. The modulation and targeting of peripheral immune mechanisms are thus promising therapeutic or preventive strategies for AD. Given the critical involvement of the endocannabinoid (eCB) system in modulating immune functions, we investigated the potential role of the main elements of such a system, namely type-1 and type-2 cannabinoid receptors (CB₁ and CB₂), and fatty acid amide hydrolase (FAAH), in distinct immune cell populations of the peripheral blood of AD patients. We found that, compared to healthy controls, CB₁ and CB₂ expression was significantly lower in the B-lymphocytes of AD patients. Moreover, we found that CB₂ was significantly lower and FAAH was significantly higher in monocytes of the same subjects. In contrast, T-lymphocytes and NK cells did not show any variation in any of these proteins. Of note, monocytic CB₂ and FAAH levels significantly correlated with clinical scores. Furthermore, the pharmacological inactivation of FAAH in monocytes and monocyte-derived macrophages obtained from AD patients was able to modulate their immune responses, by reducing production of pro-inflammatory cytokines such as TNF-α, IL-6 and IL-12, and enhancing that of the anti-inflammatory cytokine IL-10. Furthermore, FAAH blockade skewed AD monocyte-derived macrophages towards a more anti-inflammatory and pro-resolving phenotype. Collectively, our findings highlight a central role of FAAH in regulating AD monocytes/macrophages that could be of value in developing novel monocyte-centered therapeutic approaches aimed at promoting a neuroprotective environment.

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

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

The Endocannabinoid System and Invertebrate Neurodevelopment and Regeneration

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

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

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

Cannabinoid-Based Medicines and Multiple Sclerosis

The emerging role of the endocannabinoid system (ECS) in the control of symptoms and disease progression in multiple sclerosis (MS) has been highlighted by recent studies. MS is a chronic, immune-mediated, and demyelinating disorder of the central nervous system with no cure so far. It is widely reported that cannabinoids might be used to control MS symptoms and that they also might exert neuroprotective effects and slow down disease progression. The aim of this chapter is to give an overview of the main endogenous and synthetic cannabinoids used for the symptomatic amelioration of MS and their beneficial outcomes, providing new possible perspectives for the treatment of this disease.

RADIATION DAMAGE OF THE NERVOUS SYSTEM AND ENDOCANABINOIDS

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

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.

Plant-derived natural therapeutics targeting cannabinoid receptors in metabolic syndrome and its complications: A review

The endocannabinoid system (ECS) is natural physiological system in the humans. The presence of the ECS system involves different roles in body. The endocannabinoid system involves regulation of most of the centers, which regulates the hunger and leads to changes in the weight. In the present article, we reviewed the role of natural cannabinoid compounds in metabolic disorders and related complications. We studied variety of a plant-derived cannabinoids in treating the metabolic syndrome including stoutness, fatty acid liver diseases, insulin obstruction, dementia, hypertension, lipid abnormalities, non-alcoholic steatohepatitis, endothelial damage, and polycystic ovarian syndrome and so on. The activation of cannabinoid receptors demonstrates a significant number of beneficial approaches concerning metabolic syndrome and reduces the pro-inflammatory cytokines on account of aggravation, decreased oxidative stress and uneasiness, diminishes liver fibrosis, with reduces adiponectin. Pre-clinical investigations of plant-derived cannabinoids resulted in promising outcomes. The different distinctive plant-derived cannabinoids were discovered like cannabidiol (CBD), cannabinol (CBN), cannabichromene (CBC), and cannabidiol (CBG). It has been observed that endogenous cannabinoids and plant-derived cannabinoids have an advantageous impact on limiting the metabolic disorder arising due to lifestyle changes.

Targeting Endocannabinoid Metabolism: an Arrow with Multiple Tips Against Multiple Sclerosis

Multiple sclerosis (MS) is a chronic, immune-mediated disease of the central nervous system. At present, there is no definitive cure, and the few available disease-modifying options display either poor efficacy or life-threatening side effects. There is clear evidence that relapsing-remitting clinical attacks in MS are driven by inflammatory demyelination and that the subsequent disease steps, being irresponsive to immunotherapy, result from neurodegeneration. The endocannabinoid system (ECS) stands halfway between three key pathomechanisms underlying MS, namely inflammation, neurodegeneration and oxidative stress, thus representing a kingpin for the identification of novel therapeutic targets in MS. This review summarizes the current state of the art in the field of endocannabinoid metabolism modulators and their in vivo effects on relevant animal models. We also highlight key molecular underpinnings of their therapeutic efficacy as well as the potential to turn them into promising clinical candidates.

Targeting Endocannabinoid Signaling: FAAH and MAG Lipase Inhibitors

Inspired by the medicinal properties of the plant Cannabis sativa and its principal component (-)-trans-Δ⁹-tetrahydrocannabinol (THC), researchers have developed a variety of compounds to modulate the endocannabinoid system in the human brain. Inhibitors of fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL), which are the enzymes responsible for the inactivation of the endogenous cannabinoids anandamide and 2-arachidonoylglycerol, respectively, may exert therapeutic effects without inducing the adverse side effects associated with direct cannabinoid CB₁ receptor stimulation by THC. Here we review the FAAH and MAGL inhibitors that have reached clinical trials, discuss potential caveats, and provide an outlook on where the field is headed.

Cannabidiol primer for healthcare professionals

Emerging research and clinical data are demonstrating potential benefits of cannabidiol for multiple medical conditions. This article gives healthcare providers information on cannabidiol and the endocannabinoid system as a foundation on which to build their medical knowledge as the risks and benefits of CBD in various diseases are further evaluated over time.