Inhibition of CDK2 promotes inducible regulatory T-cell differentiation through TGFβ-Smad3 signaling pathway.

Inducible regulatory T-cells (iTReg) can be generated from CD4(+)Foxp3(-) naïve conventional T-cells by a combination of TGF-β and T-cell receptor (TCR) signaling. It is of enormous clinical importance to identify agents that can promote the generation and differentiation of functional iTreg cells. We have established a phenotypic screening platform to identify new compounds that can promote the TGFβ-mediated iTreg differentiation. We have found Kenpaullone, a potent CDK1, CDK2 and CDK5 inhibitor, as new enhancer for iTreg cell differentiation. Kenpaullone promotes iTreg cell differentiation through increased and prolonged transcription of foxp3 gene by enhancing TGFβ-Smad3 signaling pathway. Thus, we have demonstrated that CDK2 is the biological target of Kenpaullone and proven that CDK2 is a novel negative regulator of iTreg cell differentiation.