Endothelin-A Receptor Activation Stimulates Th17 Cell Differentiation

Th17 cells are a major contributor to many pro-inflammatory disease conditions. Endothelin 1 (ET-1) through the ETA receptor promotes inflammation, however its role in T cell differentiation, especially T helper 17 (Th17) cells, is not fully understood. Importantly, ET-1 has been shown to be elevated in people with autoimmunity, diabetes, and salt-sensitive hypertension in which augmented Th17 cells are known to contribute to the pathogenesis. Therefore, we hypothesized that ETA receptor activation mediates Th17 cell differentiation. To test our hypothesis, we first treated C57BL/6J male mice (8–12-week-old, normal chow) with the ETA receptor antagonist (ABT-627, 10mg/kg/day) in the drinking water for five weeks. We measured Th17 cells in the colon and kidneys by flow cytometry. We found that ETA receptor blockade reduced the number of Th17 cells compared to that in vehicle control mice. Indeed, the absolute number of Th17 cells decreased from 461±61 Th17 cells/per two kidneys in vehicle control to 146±29 Th17 cells per two kidneys in the ABT-627 treated group (p=0.004), and from 8372±1454 Th17 cells to 3378±936 Th17 cells (p=0.028) in the whole colon. To determine whether this observation is a direct effect on IL17A induction, we evaluated ETA receptor antagonism under Th17 polarizing conditions in vitro. Naïve CD4+ T cells were isolated from the spleen and cultured under Th17 polarizing conditions (TGFβ and IL-6) in the presence or absence of ETA receptor antagonist (BQ-123, 1μM). We found that ETA receptor blockade directly attenuated Th17 differentiation in vitro. The frequency of IL17A-expressing cells within CD4+ T cells reduced from 11.37±0.68% in media control to 9.87±0.60% in BQ-123 treated cells (p=0.0006). Similarly, the relative mean fluorescence intensity (MFI) analysis revealed a reduction in IL17A production following ETA receptor blockade from 8937±871 relative units in media control to 7132±725 relative units in BQ-123 treated cells (p=0.0136). These data taken together support our hypothesis that the ETA receptor plays a key role in Th17 differentiation. Because of the critical role of Th17 cells in pathophysiology, our findings warrant further investigations for the use of ETA receptor antagonist in pro-inflammatory conditions. Tha Luong - U2C/TL1 Deep South KUH PRIME U2C DK133422 & TL1 DK139566 from the NIH/NIDDK Patrick Molina - F31HL151264 David & Jennifer Pollock - R01 DK134562. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.