Gold nanoparticles downregulate interleukin-1?-induced pro-inflammatory responses

Interleukin 1 beta (IL-1?)-dependent inflammatory disorders, such as rheumatoid arthritis and psoriasis, pose a serious medical burden worldwide, where patients face a lifetime of illness and treatment. Organogold compounds have been used since the 1930s to treat rheumatic and other IL-1?-dependent diseases and, though their mechanisms of action are still unclear, there is evidence that gold interferes with the transmission of inflammatory signalling. Here we show for the first time that citrate-stabilized gold nanoparticles, in a size dependent manner, specifically downregulate cellular responses induced by IL-1? both in vitro and in vivo. Our results indicate that the anti-inflammatory activity of gold nanoparticles is associated with an extracellular interaction with IL-1?, thus opening potentially novel options for further therapeutic applications