Nox2 in regulatory T cells promotes angiotensin II–induced cardiovascular remodeling
Amber Emmerson, … , Giovanna Lombardi, Ajay M. Shah
Amber Emmerson, … , Giovanna Lombardi, Ajay M. Shah
Published April 24, 2018
Citation Information: J Clin Invest. 2018;128(7):3088-3101. https://doi.org/10.1172/JCI97490.
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Research Article Cardiology Immunology

Nox2 in regulatory T cells promotes angiotensin II–induced cardiovascular remodeling

Abstract

The superoxide-generating enzyme Nox2 contributes to hypertension and cardiovascular remodeling triggered by activation of the renin-angiotensin system. Multiple Nox2-expressing cells are implicated in angiotensin II–induced (Ang II–induced) pathophysiology, but the importance of Nox2 in leukocyte subsets is poorly understood. Here, we investigated the role of Nox2 in T cells, particularly Tregs. Mice globally deficient in Nox2 displayed increased numbers of Tregs in the heart at baseline, whereas Ang II–induced effector T cell (Teff) infiltration was inhibited. To investigate the role of Treg Nox2, we generated a mouse line with CD4-targeted Nox2 deficiency (Nox2fl/flCD4Cre+). These animals showed inhibition of Ang II–induced hypertension and cardiac remodeling related to increased tissue-resident Tregs and reduction in infiltrating Teffs, including Th17 cells. The protection in Nox2fl/flCD4Cre+ mice was reversed by anti-CD25 antibody depletion of Tregs. Mechanistically, Nox2–/y Tregs showed higher in vitro suppression of Teff proliferation than WT Tregs, increased nuclear levels of FoxP3 and NF-κB, and enhanced transcription of CD25, CD39, and CD73. Adoptive transfer of Tregs confirmed that Nox2-deficient cells had greater inhibitory effects on Ang II–induced heart remodeling than WT cells. These results identify a previously unrecognized role of Nox2 in modulating suppression of Tregs, which acts to enhance hypertension and cardiac remodeling.

Authors

Amber Emmerson, Silvia Cellone Trevelin, Heloise Mongue-Din, Pablo D. Becker, Carla Ortiz, Lesley A. Smyth, Qi Peng, Raul Elgueta, Greta Sawyer, Aleksandar Ivetic, Robert I. Lechler, Giovanna Lombardi, Ajay M. Shah

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Figure 5

Tregs in Nox2fl/flCD4Cre+ mice account for the inhibition of Ang II–induced hypertension and heart remodeling.

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Tregs in Nox2fl/flCD4Cre+ mice account for the inhibition of Ang II–indu...
Nox2fl/flCD4Cre+ and Nox2fl/fl littermate controls were treated with Ang II (1.1 mg/kg/d) or saline (Sham) infusion. (A–C) Relative and absolute numbers of CD45+CD4+RORγT+ (Th17) cells in heart digests by flow cytometry after 3 days of Ang II treatment. Representative plots are shown in A. (D and E) Absolute numbers of Th17 cells in aorta and kidney after 7 days of Ang II treatment. (F and G) Cardiac levels of IL-17 and IL-10 after 3 days of Ang II treatment. (H) Nox2–/y Tregs inhibit IL-17 production by CD4+CD25– cells. WT or Nox2–/y CD4+CD25– cells were stimulated with antigen-presenting cells (APCs) and anti-CD3ε Ab in the presence or absence of WT or Nox2–/y Tregs for 3 days. (I) Systolic BP response to Ang II infusion in Nox2fl/flCD4Cre+ and Nox2fl/fl mice after treatment with anti-CD25 Ab (clone PC61, 500 μg/mouse, i.p.) to deplete Tregs. (J and K) Effect of anti-CD25 Ab treatment on interstitial cardiac fibrosis (J) and cardiomyocyte cross-sectional area (CSA) (K) in mice infused with Ang II. *P < 0.05 compared with Nox2fl/fl control group, †P < 0.05 for effect of anti-CD25 Ab in Nox2fl/flCD4Cre+ mice, by 1-way ANOVA followed by Tukey’s post-test (B–H, J, and K) or 2-way ANOVA (I); n = 3–6 per group.