Pyrrolidine dithiocarbamate (PDTC) inhibits inflammatory signaling via expression of regulator of calcineurin activity 1 (RCAN1): Anti-inflammatory mechanism of PDTC through RCAN1 induction.

Pyrrolidine dithiocarbamate (PDTC) is a thiol compound that elicits anti-inflammatory effects by inhibiting NF-κB signaling. In this study, we report that regulator of calcineurin activity 1 (RCAN1) expression is induced by PDTC treatment and that increased RCAN1 expression is dependent on the generation of reactive oxygen species (ROS) and activation of p38 MAPK and JNK signaling. We also report that the ability of PDTC to induce RCAN1 is mediated by activator protein-1 (AP-1)-dependent gene transcription, and identified a functional AP-1 binding site in the RCAN1 promoter by producing mutations and conducting chromatin immunoprecipitation (ChIP) analyses. Moreover, we show that the PDTC-mediated inhibitory effect on NF-κB signaling is significantly perturbed by knocking out RCAN1. Our data provide the first evidence that PDTC prevents in vivo expression of pro-inflammatory cytokines by inducing RCAN1 expression.