Discovery and Anti-Inflammatory Activity Evaluation of a Novel CDK8 Inhibitor through Upregulation of IL-10 for the Treatment of Inflammatory Bowel Disease In Vivo

Increasing the anti-inflammatory cytokine interleukin-10 (IL-10) level is a promising strategy to suppress the progression of pathogenic inflammation including inflammatory bowel disease (IBD). Since cyclin-dependent kinase 8 (CDK8) inhibition can upregulate IL-10 abundance in activated myeloid-derived dendritic cells, it is considered to be an effective target for IBD treatment. Here, the complete discovery process of a novel CDK8 inhibitor as an anti-inflammatory agent was described. Starting with wogonin, structure-based optimization and structure–activity relationship (SAR) study were comprehensively carried out, and then lead compound 85 (N-(2-ethylphenyl)-5-(4-(piperazine-1-carbonyl)­phenyl)­nicotinamide) was developed as a potent druglike CDK8 inhibitor upregulating IL-10 both in vivo and in vitro. Also, compound 85 (with CDK8 IC50 = 56 nM, IL-10 enhancement rate 88%) exhibited effective anti-inflammatory activity in an animal model of IBD. These results confirmed that certain CDK8 inhibitor could be used as an effective anti-IBD drug.