BackgroundMultiple sclerosis (MS) is a neuroinflammatory autoimmune disease characterized by multifocal perivascular infiltration of immune cells in the central nervous system (CNS). Current treatment for MS is unsatisfactory, and we aimed to search for immunomodulatory agents from bioactive constituents of natural origin. Cordycepin (3′-deoxyadenosine), an adenosine analogue initially extracted from the fungus Cordyceps militarisa, is one of the candidates that has multiple actions. However, its effect on MS is unknown.MethodsWe first investigated the in vitro effects of cordycepin on mouse and human dendritic cells, microglial cells, macrophages, and T cell subsets. Cordycepin was administered to the experimental autoimmune encephalomyelitis (EAE) model at various time points to evaluate the effects in preventive and therapeutic model. Chemokine array and next-generation sequencing (NGS) were applied to identify the key molecules and genes involved in the mechanism. ResultsCordycepin attenuated the activation of LPS-induced mouse bone marrow-derived dendritic cells (BMDCs) and human monocyte-derived dendritic cells (MoDCs) through the inhibition of the AKT, ERK, NF-?B, and ROS pathways and impaired the migration of BMDCs through the downregulation of adhesion molecules and chemokine receptors in vitro. In EAE model, preventive treatment with cordycepin decreased the expression of trafficking factors in the CNS, inhibited the secretion of inflammatory cytokines (IFN-g , IL-6, TNF-a, and IL-17) induced by specific peptides, and attenuated clinical symptoms. A chemokine array indicated that cordycepin treatment reversed the high levels of CCL6, PARRES2, IL-16, CXCL10, and CCL12 in the brain and spinal cord of EAE mice, consistent with the RNA-seq data. Moreover, cordycepin suppressed the release of neuroinflammatory cytokines by activated microglial cells, macrophages, Th17 cells, Tc1 cells, and Th1 cells in vitro. Furthermore, cordycepin treatment exerted therapeutic effects on attenuating the clinical disease severity in the early disease onset stage and late disease progression stage. ConclusionsOur study suggests that cordycepin treatment may not only prevent the occurrence of MS by inhibiting DC activation and migration but also potentially ameliorates the progression of MS by reducing neuroinflammation, which may provide insights into the development of new approaches for the treatment of MS.