Abstract 083: γ/δ T Cells Play a Role in Development of Hypertension

Abstract

Objective: Both innate antigen-presenting cells and the adaptive immune system have been shown to play a role in the development of hypertension. Nevertheless, the T cell subsets involved in the pathophysiology of hypertension remains unclear. There is a small subset of “innate-like” T cells expressing the γ/δ T cell receptor (TCR) rather than the α/β TCR that could play a role bridging the innate and adaptive immune systems. We previously observed that angiotensin (Ang) II caused an increase in number and activation of γ/δ T cells and Ang II-induced systolic blood pressure (SBP) rise and vascular injury were blunted in Tcr δ -/- mice, which are devoid of γ/δ T cells. In order to further characterize the role of γ/δ T cells in hypertension, we determined whether Ang II-effects would be blunted by antibody-induced depletion of γ/δ T cells. In addition, we tested whether SBP in human could be predicted by combining the expression of genes encoding TCRGC (TCR gamma constant region) and pro-inflammatory markers of γ/δ T cells in peripheral blood mononuclear cells (PBMC). Method and Results: Thirteen to 15-week old male C57BL/6 wild-type (WT) mice were infused with Ang II (490 ng/kg/min, SC) for 14 days and injected IP with anti-γ/δ TCR or control isotype antibodies 1 day before and at day 6 of Ang II infusion. Depletion of γ/δ T cells decreased SBP (147±2 vs 167 ± 3 mm Hg, P <0.05) and restored mesenteric artery relaxation responses to acetylcholine (E max : 90±4 vs 62 ± 8%, P <0.05) compared to isotype antibody-treated mice. Using the SBP data and the PBMC gene expression profile (GSE12288) of 222 human subjects, we predicted with a supervised machine learning approach SBP by combining the gene expression of TCRGC and pro-inflammatory makers including interleukin-17A, interferon-γ and their receptors (R=0.23, P <0.001). Conclusion: Antibody-induced depletion further demonstrates the role of γ/δ T cells in Ang II-induced SBP elevation and vascular injury. Prediction of SBP using PBMC gene expression of γ/δ T cells and pro-inflammatory markers suggests that γ/δ T cells contribute to the development of human hypertension.