sp2-Iminosugar glycolipids as inhibitors of lipopolysaccharide-mediated human dendritic cell activation in vitro and of acute inflammation in mice in vivo.

Glycolipid mimetics consisting of a bicyclic polyhydroxypiperidine-cyclic carbamate core and a pseudoanomeric hydrophobic tail, termed sp2-iminosugar glycolipids (sp2-IGLs), target microglia during neuroinflammatory processes. Here we have synthesized and investigated new variants of sp2-IGLs for their ability to suppress the activation of human monocyte-derived dendritic cells (DCs) by lipopolysaccharide (LPS) signaling through Toll-like receptor 4. We report that the best lead was (1R)-1-dodecylsulfonyl-5N,6O-oxomethylidenenojirimycin (DSO2-ONJ), able to inhibit LPS-induced TNFα production and maturation of DCs. Immunovisualization experiments, using a mannoside glycolipid conjugate (MGC) that also suppress LPS-mediated DC activation as control, evidenced a distinct mode of action for the sp2-IGLs: unlike MGCs, DSO2-ONJ did not elicit internalization of the LPS co-receptor CD14 or induce its co-localization with the Toll-like receptor 4. In a mouse model of LPS-induced acute inflammation, DSO2-ONJ demonstrated anti-inflammatory activity by inhibiting the production of the pro-inflammatory interleukin-6. The ensemble of the data highlights sp2-IGLs as a promising new class of molecules against inflammation by interfering in Toll-like receptor intracellular signaling.