Antimalarial Drug Artemotil Promotes Induction of Type 1 Regulatory T Cells.

Artemisinin and its derivatives, used as front-line anti-malarial drugs, exhibit anti-inflammatory properties. They were found to suppress the generation and function of Th1 and Th17 cells while promoting the generation of Foxp3 + regulatory T cells (Tregs). However, the specific role of Artemotil (β-arteether) in modulating the generation and functions of CD4 + T cells, particularly Type 1 regulatory T cells (Tr1), remains to be explored. Tr1 cells are one of the key cell types that are essential for regulating inflammatory response through IL-10. In this study, we report that Artemotil selectively promotes generation of Tr1 cells induced by IL-27 by upregulating signature genes of Tr1 cells, such as c-Maf, AhR, prdm1, IRF-1, and Batf, while inhibiting the Th1, Th2, and Th17 cells generation. We found that co-administration of Artemotil with anti-CD3 antibody increases the induction of IL-10 and frequency of Tr1 cells while suppressing Th1 and Th17 cells in vivo. Artemotil suppresses T-cell-induced enteropathy and alleviates the signs of colitis associated with the increased frequencies of Tr1 cells. Taken together, our data suggest that Artemotil provides protection in T-cell-mediated colitis by increasing the expansion of Tr1 cells and inhibiting the generation of Th1 and Th17 cells.