Endothelin regulates function of IL-17-producing T cell subset

Although endothelin (ET) is known to play pleiotropic roles in various pathological conditions, its relation to autoimmune disease has not been elucidated. Here, we focused on interleukin (IL)-17, which is closely related to the pathogenesis of multiple sclerosis, and investigated the effect of ET receptor blockers on the production of IL-17 by T lymphocytes.

Lymph node cells from mice at 8 days post-immunization with MOG35-55 were stimulated in vitro with MOG35-55 in the presence or absence of an ET receptor blocker (BQ123 for ETA or BQ788 for ETB). Naïve T cells from mice were subjected to an in vitro model of Th17 differentiation, and ET-mediated IL-17 production was investigated under the states of Th17 differentiation and activation.

ELISA revealed that MOG35-55-induced IL-17 production was significantly inhibited by BQ123 but not BQ788. Consistent with the ELISA results for IL-17, the frequency of CD4(+) T cells producing IL-17 but not IFN-γ was reduced by BQ123. Under the differentiating state from naïve T cells to Th17 cells, the spontaneous release of IL-17 from CD4(+) T cells was increased, which was insensitive to BQ123, indicating that ET/ETA signaling did not affect Th17 differentiation. After the time period of Th17 differentiation, however, the increase in IL-17 production by restimulation of the cells with anti-CD3 plus anti-CD28 antibodies was significantly inhibited by BQ123.

We demonstrated that ET/ETA signaling plays a crucial role in IL-17 production by Th17. BQ123 might be expected to be a future therapeutic drug for multiple sclerosis.