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

Abstract

Abstract 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, the neuroprotective and anti-inflammatory effects of the ECS have been studied, and inhibiting the degradation of the endocannabinoid 2-arachydonoylglycerol (2-AG) is emerging as a promising strategy to counteract brain damage in MS. In this study, a systemic and preventive in vivo treatment with MAGLi 432, the reversible inhibitor of monoacylglycerol lipase (MAGLi), was performed in experimental autoimmune encephalomyelitis (EAE) mice. Clinical, biochemical, electrophysiological and immunofluorescence analyses were carried out to evaluate the impact of the drug on motor disability, neuroinflammation and synaptic damage. MAGLi 432 induced a less severe EAE disease, accompanied by an increase of 2-AG and a reduction of acid arachidonic (AA) and prostaglandins (PGs) brain levels. MAGLi 432 reversed the striatal synaptic hyperexcitability promoted by EAE neuroinflammatory insult. Furthermore, MAGLi 432 reduced both astrogliosis and microgliosis in EAE, as microglia/macrophages density was reduced, in parallel with a less reactive morphology. By flow cytometry analysis, we also observed less infiltrating CD45 + and CD3 + cells in the brain of MAGLi 432-treated EAE mice. In conclusion, in vivo MAGL inhibition promotes a significant amelioration of EAE clinical disability and striatal inflammatory synaptopathy through potent anti-inflammatory effects, including an enhanced 2-AG tone and reduced PGs levels, gliosis, and lymphocyte infiltration. Overall, these data provide new mechanistic insights into the neuroprotective role of the ECS during neuroinflammation and reveal the therapeutic potential of MAGLi-based drugs in MS inflammatory and neurodegenerative brain damage.