Sulforaphane protects from T cell mediated autoimmune disease by inhibition of interleukin 23 and 12 in dendritic cells

Sulforaphane (SFN), an isothiocyanate, is part of an important group of naturally occurring small molecules with antiinflammatory properties. Even though the published reports are vague, most are best conceivable with an inhibition of T cell functions. We therefore analyzed the effect of SFN on T cell-mediated autoimmune disease. Feeding mice with SFN protected from severe experimental autoimmune encephalomyelitis (EAE). Disease amelioration was associated with reduced interleukin (IL)-17 and IFN-gamma expression in draining lymph nodes. In vitro, SFN treatment of T cells did not directly alter T cell cytokine secretion. In contrast, SFN treatment of dendritic cells (DC) inhibited TLR4-induced IL-12 and IL-23 production and the cytokine profile of T cells stimulated by SFN-treated DC. SFN suppressed TLR4-induced nuclear factor kappa B (NFB) activity, without affecting the degradation of its inhibitor (IB). Instead, SFN treatment of DC resulted in strong expression of the stress response protein heme oxygenase-1 (HO-1), which interacts with NFB p65 and inhibits its activity. Consistent with these findings, HO-1 bound to p65 and subsequently inhibited the p65 promoter activity within the IL23a and IL12b promoter region. Importantly, SFN suppressed Il23a and Il12b expression in vivo and silenced Th17/Th1 responses within the CNS . Our data show that SFN improves Th17/Th1-mediated autoimmune disease by inducing HO-1 and inhibiting p65-regulated IL-23 and IL-12 expression.

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Geisel J, Brück J, Glocova I, Dengler K, Sinnberg T, Rothfuss O, Walter M, Schulze-Osthoff K, Röcken M, Ghoreschi K