glyceryl-2-arachidonate and Multiple-Sclerosis

Recent years have yielded significant advances in our understanding of microglia, the immune cells of the central nervous system (CNS). Microglia are key players in CNS development, immune surveillance, and the maintenance of proper neuronal function throughout life. In the healthy brain, homeostatic microglia have a unique molecular signature. In neurological diseases, microglia become activated and adopt distinct transcriptomic signatures, including disease-associated microglia (DAM) implicated in neurodegenerative disorders. Homeostatic microglia synthesise the endogenous cannabinoids 2-arachidonoylglycerol and anandamide and express the cannabinoid receptors CB1 and CB2 at constitutively low levels. Upon activation, microglia significantly increase their synthesis of endocannabinoids and upregulate their expression of CB2 receptors, which promote a protective microglial phenotype by enhancing their production of neuroprotective factors and reducing their production of pro-inflammatory factors. Here, we summarise the effects of the microglial cannabinoid system in the CNS demyelinating disease multiple sclerosis, the neurodegenerative diseases Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis, chronic inflammatory and neuropathic pain, and psychiatric disorders including depression, anxiety and schizophrenia. We discuss the therapeutic potential of cannabinoids in regulating microglial activity and highlight the need to further investigate their specific microglia-dependent immunomodulatory effects.

Topics: Alzheimer Disease; Amyotrophic Lateral Sclerosis; Anxiety Disorders; Arachidonic Acids; Chronic Pain; Depressive Disorder; Endocannabinoids; Glycerides; Humans; Mental Disorders; Microglia; Multiple Sclerosis; Neuralgia; Neurodegenerative Diseases; Parkinson Disease; Polyunsaturated Alkamides; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Schizophrenia

The failure to remyelinate and regenerate is a critical impediment to recovery in multiple sclerosis (MS), resulting in severe dysfunction and disability. The chondroitin sulfate proteoglycans (CSPGs) that accumulate in MS lesions are thought to be linked to the failure to regenerate, impeding oligodendrocyte precursor cell (OPC) differentiation and neuronal growth. The potential of endocannabinoids to influence MS progression may reflect their capacity to enhance repair processes. Here, we investigated how 2-arachidonoylglycerol (2-AG) may affect the production of the CSPGs neurocan and brevican by astrocytes in culture. In addition, we studied whether 2-AG promotes oligodendrocyte differentiation under inhibitory conditions in vitro. Following treatment with 2-AG or by enhancing its endogenous tone through the use of inhibitors of its hydrolytic enzymes, CSPG production by rat and human TGF-β1 stimulated astrocytes was reduced. These effects of 2-AG might reflect its influence on TGF-β1/SMAD pathway, signaling that is involved in CSPG upregulation. The matrix generated from 2-AG-treated astrocytes is less inhibitory to oligodendrocyte differentiation and significantly, 2-AG administration directly promotes the differentiation of rat and human oligodendrocytes cultured under inhibitory conditions. Overall, the data obtained favor targeting the endocannabinoid system to neutralize CSPG accumulation and to enhance oligodendrocyte differentiation.

Topics: Animals; Arachidonic Acids; Astrocytes; Cell Differentiation; Chondroitin Sulfate Proteoglycans; Endocannabinoids; Glycerides; Multiple Sclerosis; Oligodendrocyte Precursor Cells; Oligodendroglia; Rats; Remyelination

Remyelination is an endogenous process by which functional recovery of damaged neurons is achieved by reinstating the myelin sheath around axons. Remyelination has been documented in multiple sclerosis (MS) lesions and experimental models, although it is often incomplete or fails to affect the integrity of the axon, thereby leading to progressive disability. Microglia play a crucial role in the clearance of the myelin debris produced by demyelination and in inflammation-dependent OPC activation, two processes necessary for remyelination to occur. We show here that following corpus callosum demyelination in the TMEV-IDD viral murine model of MS, there is spontaneous and partial remyelination that involves a temporal discordance between OPC mobilization and microglia activation. Pharmacological treatment with the endocannabinoid 2-AG enhances the clearance of myelin debris by microglia and OPC differentiation, resulting in complete remyelination and a thickening of the myelin sheath. These results highlight the importance of targeting microglia during the repair processes in order to enhance remyelination.

Topics: Animals; Arachidonic Acids; Axons; Cell Differentiation; Corpus Callosum; Demyelinating Diseases; Disease Models, Animal; Endocannabinoids; Female; Glycerides; Male; Mice; Mice, Inbred Strains; Microglia; Multiple Sclerosis; Myelin Sheath; Oligodendrocyte Precursor Cells; Oligodendroglia; Remyelination; Theilovirus

Topics: Animals; Arachidonic Acids; Cells, Cultured; Disease Models, Animal; Endocannabinoids; Glycerides; Male; Mice, Inbred C57BL; Monoacylglycerol Lipases; Multiple Sclerosis; Myelin Sheath; Oligodendroglia; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2

The failure to undergo remyelination is a critical impediment to recovery in multiple sclerosis. Chondroitin sulfate proteoglycans (CSPGs) accumulate at demyelinating lesions creating a nonpermissive environment that impairs axon regeneration and remyelination. Here, we reveal a new role for 2-arachidonoylglycerol (2-AG), the major CNS endocannabinoid, in the modulation of CSPGs deposition in a progressive model of multiple sclerosis, the Theiler's murine encephalomyelitis virus-induced demyelinating disease. Treatment with a potent reversible inhibitor of the enzyme monoacylglycerol lipase, which accounts for 85% of the 2-AG degradation in the mouse CNS, modulates neuroinflammation and reduces CSPGs accumulation and astrogliosis around demyelinated lesions in the spinal cord of Theiler's murine encephalomyelitis virus-infected mice. Inhibition of 2-AG hydrolysis augments the number of mature oligodendrocytes and increases MBP, leading to remyelination and functional recovery of mice. Our findings establish a mechanism for 2-AG promotion of remyelination with implications in axonal repair in CNS demyelinating pathologies.

Topics: Animals; Arachidonic Acids; Cannabinoid Receptor Agonists; Dose-Response Relationship, Drug; Down-Regulation; Endocannabinoids; Female; Glycerides; Mice; Multiple Sclerosis; Nerve Fibers, Myelinated; Neurogenesis; Proteoglycans

A combination of molecular modeling and structure-activity relationship studies has been used to fine-tune CB2 selectivity in the chromenopyrazole ring, a versatile CB1/CB2 cannabinoid scaffold. Thus, a series of 36 new derivatives covering a wide range of structural diversity has been synthesized, and docking studies have been performed for some of them. Biological evaluation of the new compounds includes, among others, cannabinoid binding assays, functional studies, and surface plasmon resonance measurements. The most promising compound [43 (PM226)], a selective and potent CB2 agonist isoxazole derivative, was tested in the acute phase of Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD), a well-established animal model of primary progressive multiple sclerosis. Compound 43 dampened neuroinflammation by reducing microglial activation in the TMEV.

Topics: Dose-Response Relationship, Drug; HEK293 Cells; Humans; Models, Molecular; Molecular Structure; Multiple Sclerosis; Pyrazoles; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Structure-Activity Relationship

We report the discovery of compound 4a, a potent β-lactam-based monoacylglycerol lipase (MGL) inhibitor characterized by an irreversible and stereoselective mechanism of action, high membrane permeability, high brain penetration evaluated using a human in vitro blood-brain barrier model, high selectivity in binding and affinity-based proteomic profiling assays, and low in vitro toxicity. Mode-of-action studies demonstrate that 4a, by blocking MGL, increases 2-arachidonoylglycerol and behaves as a cannabinoid (CB1/CB2) receptor indirect agonist. Administration of 4a in mice suffering from experimental autoimmune encephalitis ameliorates the severity of the clinical symptoms in a CB1/CB2-dependent manner. Moreover, 4a produced analgesic effects in a rodent model of acute inflammatory pain, which was antagonized by CB1 and CB2 receptor antagonists/inverse agonists. 4a also relieves the neuropathic hypersensitivity induced by oxaliplatin. Given these evidence, 4a, as MGL selective inhibitor, could represent a valuable lead for the future development of therapeutic options for multiple sclerosis and chronic pain.

Topics: Animals; Arachidonic Acids; Blood-Brain Barrier; Brain; Cell Membrane; Drug Design; Encephalomyelitis, Autoimmune, Experimental; Endocannabinoids; Glycerides; HEK293 Cells; Humans; Mice; Models, Molecular; Monoacylglycerol Lipases; Multiple Sclerosis; Mutagenicity Tests; Neuralgia; Organoplatinum Compounds; Oxaliplatin; Pain; Permeability; Proteomics; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Structure-Activity Relationship

Endocannabinoids (eCBs) play a role in the modulation of neuroinflammation, and experimental findings suggest that they may be directly involved in the pathogenesis of multiple sclerosis (MS). The objective of our study was to measure eCB levels in the cerebrospinal fluid (CSF) of patients with MS.. Arachidonoylethanolamine (anandamide, AEA), palmotylethanolamide (PEA), 2-arachidonoylglycerol (2-AG) and oleoylethanolamide (OEA) levels were measured in the CSF of 50 patients with MS and 20 control subjects by isotope dilution gas-chromatography/mass-spectrometry. Patients included 35 patients with MS in the relapsing-remitting (RR) form of the disease, 20 in a stable clinical phase and 15 during a relapse, and 15 patients with MS in the secondary progressive (SP) form.. Significantly reduced levels of all the tested eCBs were found in the CSF of patients with MS compared to control subjects, with lower values detected in the SP MS group. Higher levels of AEA and PEA, although below those of controls, were found in the CSF of RR MS patients during a relapse. Higher levels of AEA, 2-AG and OEA were found in patients with MRI gadolinium-enhancing (Gd+) lesions.. The present findings suggest the presence of an impaired eCB system in MS. Increased CSF levels of AEA during relapses or in RR patients with Gd+ lesions suggest its potential role in limiting the ongoing inflammatory process with potential neuroprotective implications. These findings provide further support for the development of drugs targeting eCBs as a potential pharmacological strategy to reduce the symptoms and slow disease progression in MS.

Topics: Adult; Arachidonic Acids; Brain; Cannabinoid Receptor Modulators; Disability Evaluation; Disease Progression; Endocannabinoids; Female; Gas Chromatography-Mass Spectrometry; Glycerides; Humans; Inflammation; Magnetic Resonance Imaging; Male; Multiple Sclerosis; Oleic Acids; Polyunsaturated Alkamides; Severity of Illness Index

The ability of cannabinoids to modulate both inflammatory and degenerative neuronal damage prompted investigations on the potential benefits of such compounds in multiple sclerosis (MS) and in animal models of this disorder. Here we measured endocannabinoid levels, metabolism and binding, and physiological activities in 26 patients with MS (17 females, aged 19-43 years), 25 healthy controls and in mice with experimental autoimmune encephalomyelitis (EAE), a preclinical model of MS. Our results show that MS and EAE are associated with significant alterations of the endocannabinoid system. We found that anandamide (AEA), but not 2-arachidonoylglycerol (2-AG), was increased in the CSF of relapsing MS patients. AEA concentrations were also higher in peripheral lymphocytes of these patients, an effect associated with increased synthesis and reduced degradation of this endocannabinoid. Increased synthesis, reduced degradation, and increased levels of AEA were also detected in the brains of EAE mice in the acute phase of the disease, possibly accounting for its anti-excitotoxic action in this disorder. Accordingly, neurophysiological recordings from single neurons confirmed that excitatory transmission in EAE slices is inhibited by CB1 receptor activation, while inhibitory transmission is not. Our study suggests that targeting the endocannabinoid system might be useful for the treatment of MS.

Topics: Acute Disease; Adult; Animals; Arachidonic Acids; Brain; Cannabinoid Receptor Modulators; Corpus Striatum; Disease Models, Animal; Dronabinol; Electrophysiology; Encephalomyelitis, Autoimmune, Experimental; Endocannabinoids; Female; Glycerides; Humans; Lymphocytes; Magnetic Resonance Imaging; Male; Mice; Mice, Inbred C57BL; Multiple Sclerosis; Neuroprotective Agents; Patch-Clamp Techniques; Polyunsaturated Alkamides; Synaptic Transmission; Tissue Culture Techniques

Recent studies have addressed the changes in endocannabinoid ligands and receptors that occur in multiple sclerosis, as a way to explain the efficacy of cannabinoid compounds to alleviate spasticity, pain, tremor, and other signs of this autoimmune disease. Using Lewis rats with experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis, we recently found a decrease in cannabinoid CB1 receptors mainly circumscribed to the basal ganglia, which could be related to the motor disturbances characteristic of these rats. In the present study, using the same model, we explored the potential changes in several neurotransmitters in the basal ganglia that might be associated with the motor disturbances described in these rats, but we only found a small increase in glutamate contents in the globus pallidus. We also examined whether the motor disturbances and the changes of CB1 receptors found in the basal ganglia of EAE rats disappear after the treatment with rolipram, an inhibitor of type IV phosphodiesterase able to supress EAE in different species. Rolipram attenuated clinical decline, reduced motor inhibition, and normalized CB1 receptor gene expression in the basal ganglia. As a third objective, we examined whether EAE rats also exhibited changes in endocannabinoid levels as shown for CB1 receptors. Anandamide and 2-arachidonoylglycerol levels decreased in motor related regions (striatum, midbrain) but also in other brain regions, although the pattern of changes for each endocannabinoid was different. Finally, we hypothesized that the elevation of the endocannabinoid activity, following inhibition of endocannabinoid uptake, might be beneficial in EAE rats. AM404, arvanil, and OMDM2 were effective to reduce the magnitude of the neurological impairment in EAE rats, whereas VDM11 did not produce any effect. The beneficial effects of AM404 were reversed by blocking TRPV1 receptors with capsazepine, but not by blocking CB1 receptors with SR141716, thus indicating the involvement of endovanilloid mechanisms in these effects. However, a role for CB1 receptors is supported by additional data showing that CP55,940 delayed EAE progression. In summary, our data suggest that reduction of endocannabinoid signaling is associated with the development of EAE in rats. We have also proved that the reduction of CB1 receptors observed in these rats is corrected following treatment with a compound used in EAE such as rolipram. In addition, the direct or i

Topics: 3',5'-Cyclic-AMP Phosphodiesterases; Animals; Arachidonic Acids; Basal Ganglia; Brain; Cannabinoid Receptor Modulators; Capsaicin; Cyclic Nucleotide Phosphodiesterases, Type 4; Disease Models, Animal; Encephalomyelitis, Autoimmune, Experimental; Endocannabinoids; Gene Expression; Glycerides; Male; Multiple Sclerosis; Phosphodiesterase Inhibitors; Polyunsaturated Alkamides; Rats; Rats, Inbred Lew; Receptor, Cannabinoid, CB1; Receptors, Cannabinoid; Rolipram; TRPV Cation Channels

Spasticity is a complicating sign in multiple sclerosis that also develops in a model of chronic relapsing experimental autoimmune encephalomyelitis (CREAE) in mice. In areas associated with nerve damage, increased levels of the endocannabinoids, anandamide (arachidonoylethanolamide, AEA) and 2-arachidonoyl glycerol (2-AG), and of the AEA congener, palmitoylethanolamide (PEA), were detected here, whereas comparable levels of these compounds were found in normal and non-spastic CREAE mice. While exogenously administered endocannabinoids and PEA ameliorate spasticity, selective inhibitors of endocannabinoid re-uptake and hydrolysis-probably through the enhancement of endogenous levels of AEA, and, possibly, 2-arachidonoyl glycerol-significantly ameliorated spasticity to an extent comparable with that observed previously with potent cannabinoid receptor agonists. These studies provide definitive evidence for the tonic control of spasticity by the endocannabinoid system and open new horizons to therapy of multiple sclerosis, and other neuromuscular diseases, based on agents modulating endocannabinoid levels and action, which exhibit little psychotropic activity.

Topics: Amides; Animals; Arachidonic Acids; Brain; Cannabinoid Receptor Modulators; Cannabinoids; Disease Models, Animal; Encephalomyelitis, Autoimmune, Experimental; Endocannabinoids; Ethanolamines; Glycerides; Humans; Mice; Mice, Inbred Strains; Multiple Sclerosis; Palmitic Acids; Piperidines; Polyunsaturated Alkamides; Pyrazoles; Receptors, Cannabinoid; Receptors, Drug; Rimonabant; Spasm; Spinal Cord