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-gamma 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.