Itaconate and dimethyl itaconate upregulate IL-6 production in the LPS-induced inflammation in mice

Itaconate is one of the most studied immunometabolites produced by myeloid cells during inflammatory response. It mediates a wide range of anti-inflammatory and immunoregulatory effects and plays a role in a number of pathological states, including autoimmunity and cancer. Itaconate and its derivatives are considered potential therapeutic agents for the treatment of inflammatory diseases. While immunoregulatory effects of itaconate have been extensively studied in vitro and using knockout mouse models, less is known about how therapeutic administration of this metabolite regulates inflammatory response in vivo. Here, we investigate the immunoregulatory properties of exogenous administration of itaconate and its derivative dimethyl itaconate in a mouse model of lipopolysaccharide-induced inflammation. The data show that administration of itaconate or dimethyl itaconate controls systemic production of multiple cytokines, including increased IL-10 production. However, only dimethyl itaconate was able to suppress systemic production of IFNγ and IL-1β. In contrast to in vitro data, administration of itaconate or dimethyl itaconate in vivo resulted in systemic upregulation of IL-6 in the blood. Electrophilic stress due to itaconate or dimethyl itaconate was not responsible for IL-6 upregulation. However, inhibition of succinate dehydrogenase with dimethyl malonate also resulted in elevated systemic levels of IL-6 and IL-10. Taken together, our study reports a novel effect of exogenous itaconate and its derivative dimethyl itaconate on the production of IL-6 in vivo, with important implications for the development of itaconate-based anti-inflammatory therapies.