[74] Intravenous administration of miR-124 at the effector phase of disease ameliorated EAE and reduced neuroinflammation probably through its effect on macrophages, whereby miR-124 is able to promote a phenotypic switch from classically to alternatively activated macrophage, through indirect down-regulation of transcription factor PU.1, and thereby decreased expression of activation markers CD45, MHC class II and CD86, via inhibition of C/EBP-α.[74] Such a function is probably also Dabrafenib concentration at play in the maintenance of a quiescent microglial phenotype in the normal CNS. Alternatively activated microglia can secrete a wide range of molecules that can have a neuroprotective effect

in MS/EAE, either directly, such as insulin-like growth factor 1, which promotes proliferation and differentiation of neural progenitor cells,[75, 76] or indirectly through their anti-inflammatory effect, such as the anti-inflammatory cytokines

IL-4, IL-10 and TGF-β. In vitro studies have shown that IL-4-stimulated microglia are able to instruct neural progenitor cells to differentiate into oligodendrocytes, at least in part through release of insulin-like growth factor 1.[75] A number of disease-modifying drugs that have been, or are in the process of being, approved for MS, can potentially affect microglial phenotype directly or indirectly. We shall address this issue for the two most used first-line treatments for relapsing–remitting MS, IFN-β and glatiramer acetate (GA), and for the recently approved fingolimod and dimethyl fumarate (DMF). The precise mechanisms this website through which IFN-β exerts its immunomodulatory effect in

MS are still uncertain, but generally include inhibition and apoptosis of autoreactive T cells, induction of regulatory T cells, inhibition of leucocyte extravasation through the BBB, and modulation of cytokine expression.[77] Its effect on microglia has, as yet, been poorly investigated, with only scant in vitro studies reported. Kim et al.[78] showed that IFN-β induced the expression of chemokines such as RANTES and MIP-1b in primary human microglia, through activation of at least three different partially interconnected signalling cascades Nintedanib (BIBF 1120) including nuclear factor-κB, activator protein-1 and Janus kinase/signal transducer and activator of transcription. Kawanokuchi et al.[79] addressed the effect of IFN-β on murine microglial functions such as antigen presentation and secretion of inflammatory mediators; they showed that IFN-β inhibits the antigen-presenting function of microglia through suppression of IFN-γ-induced MHC class II expression and down-regulation of the co-stimulatory molecule B7-1, and suppresses differentiation of pathogenic autoreactive T helper type 1 T cells through down-regulation of microglial IL-12 production. Surprisingly, and in accordance with the study of Dasgupta et al.