AUTOREACTIVE T CELLS TO ANGIOTENSIN II TYPE 1 RECEPTOR IN SALT-DEPENDENT HYPERTENSION DUE TO PRIMARY ALDOSTERONISM

Abstract

Objective: Compelling evidence suggested a role of acquired immunity in hypertension and hypertension-mediated organ damage (HMOD), but its pathogenic role is still unknown. Primary Aldosteronism (PA), the paradigm of salt-dependent hypertension, is characterised by a more prominent HMOD than primary hypertension and by high titer of autoantibodies against the angiotensin type-1 receptor (AT1R). As T cells are broadly recognised as HMOD-mediators we investigated: 1) the presence of AT1R-autoreactive T cells in PA; 2) aldosterone rapid and chronic effect on AT1R-autoreactive T lymphocytes; 3) the presence and functional role of aldosterone receptors on T lymphocytes. Design and Methods: The presence of AT1R-autoreactive T cells in 11 PA patients was investigated by flow cytometry after stimulation with pool of peptides spanning the full length of AT1R. The expression of mineralocorticoid receptor (MR) and G Protein-Coupled Estrogen Receptor (GPER) on T cells was tested by measuring mRNA copy number and immunoblotting from healthy donors and PA patients. PBMCs from PA patients were exposed to aldosterone 10-10 M with or without MR antagonist (canrenone) and GPER agonist (G1) and antagonist (G36). We evaluated the effect of aldosterone on CD8+ T cells by measuring IFN? release with flow cytometry. Results: PA patients were found to have CD8+ AT1R-autoreactive T cells after activation of PBMC with AT1R peptides. MR and GPER were detected both at mRNA and protein level in CD4+ and CD8+ T cells with the following rank of expression GR>MR>>GPER. Aldosterone significantly increased IFN? release in CD8+ T-cell both under chronic and acute stimulation. Chronic exposure to aldosterone increased IFN-? production by CD8+ T cells by acting via the MR, as it was prevented (p<0.004) by canrenone, while the rapid aldosterone action was MR and GPER mediated, as it was reduced by canrenone (p<0.003), but also by G36 (p<0.02), and mimicked by G1. Conclusion: These results showed the presence of AT1R-autoreactive T cells in patients with PA and demonstrates that, upon of MR and GPER receptor stimulation with aldosterone, AT1-R specific CD8+ T cells undergo profound changes that mediated a strong cytotoxic response towards AT1-R-expressing organs.