The histone deacetylase inhibitor ITF2357 reduces production of pro-inflammatory cytokines in vitro and systemic inflammation in vivo

We studied inhibition of histone deacetylases (HDACs), which results in the unraveling of chromatin, facilitating increased gene expression. ITF2357, an orally active, synthetic inhibitor of HDACs, was evaluated as an anti-inflammatory agent. In lipopolysaccharide (LPS)-stimulated cultured human peripheral blood mononuclear cells (PBMCs), ITF2357 reduced by 50% the release of tumor necrosis factor-alpha (TNF alpha) at 10 to 22 nM, the release of intracellular interleukin (IL)-1 alpha at 12 nM, the secretion of IL-1 beta at 12.5 to 25 nM, and the production of interferon-gamma (IFN gamma) at 25 nM. There was no reduction in IL-8 in these some cultures. Using the combination of IL-12 plus IL-18, IFN gamma and IL-6 production was reduced by 50% at 12.5 to 25 nM, independent of decreased IL-1 or TNF alpha. There was no evidence of cell death in LPS-stimulated PBMCs at 100 nM ITF2357, using assays for DNA degradation, annexin V, and caspase-3/7. By Northern blotting of PBMCs, there was a 50% to 90% reduction in LPS-induced steady-state levels of TNF alpha and IFN gamma mRNA but no effect on IL-1 beta or IL-8 levels. Real-time PCR confirmed the reduction in TNF alpha RNA by ITF2357. Oral administration of 1.0 to 10 mg/kg ITF2357 to mice reduced LPS-induced serum TNF alpha and IFN gamma by more than 50%. Anti-CD3-induced cytokines were not suppressed by ITF2357 in PBMCs either in vitro or in the circulation in mice. In concanavalin-A-induced hepatitis, 1 or 5 mg/kg of oral ITF2357 significantly reduced liver damage. Thus, low, nonapoptotic concentrations of the HDAC inhibitor ITF2357 reduce pro-inflammatory cytokine production in primary cells in vitro and exhibit anti-inflammatory effects in vivo.