Abstract 025: Role Of The C-C Motif Chemokine Ligand 5 (CCL5) And Its Receptor, C-C Motif Chemokine Receptor 5 (CCR5) In The Genesis Of Aldosterone-induced Hypertension, Vascular Dysfunction, And End-organ Damage

Background: Hyperaldosteronism (HA) is the most common cause of endocrine hypertension. CCL5 is a pro-inflammatory chemokine acting primarily via C-C Motif Chemokine Receptor 5 (CCR5). We hypothesize that HA leads to hypertension, vascular injury, and renal demage via CCL5/CCR5 and Nox1-dependent mechanisms. Methods: 10-12-weeks-old male wild type (CCR5+/+) and CCR5 receptor knockout (CCR5-/-) mice were infused with aldosterone for 14 days (600ug/Kg/day, osmotic mini-pump). Endothelial function was studied in aortae and blood pressure was analyzed by radiotelemetry. Mouse endothelial cells (MEC) were used to examine the molecular mechanisms. Results: HA increased circulating CCL5 levels [Vehicle: 7.41±1.6 vs. HA: 13.2±1.4 (pg/mL)] and reduced acetylcholine (ACH)-induced vasodilation (% relaxation) in CCR5+/+, which was abolished by inhibiting Nox1 (NOXA1ds, 10 μM) [Vehicle: 91.2±2.1 vs. HA: 42.7±3.9 vs. HA+NOXA1ds: 89.7±1.9]. To understand if CCL5 induces endothelial dysfunction via CCR5 and Nox1, aortae were incubated with CCL5 (100 ng/mL for 24 h) with vehicle or CCR5 antagonist (Maraviroc, 40 μM) or NOXA1ds and endothelial function and Nox1 expression were analyzed. CCL5 treatment induced endothelial dysfunction [ACH response, Vehicle: 90.1±1.9 vs. CCL5: 31.9±2.7] and increased Nox1 expression, which were blunted by Maraviroc or NOXA1ds, indicating that CCL5 affects endothelial function dependent on CCR5 and Nox1. We found that CCR5-/- mice are protected from HA-induced endothelial dysfunction, hypertension [mean arterial pressure (mmHg) - CCR5+/+: 154.8±3.7 vs. CCR5-/-: 104.5±2.9], and renal damage (analyzed by NGAL, Synaptopodin, and Colagen III gene expressions). On mechanistic levels, we found that CCL5 decreases nitric oxide production, leads to NF-κB activation, induces oxidative stress (elevated superoxide anion and H2O2) and ICAM and VCAM expressions in MEC, which were associated with higher macrophage adhesion, such effects were prevented by Maraviroc. Conclusion: These findings reveal a novel signaling pathway in HA-associated vascular and renal injuries and hypertension, CCL5 activates CCR5 stimulating NF-κB and Nox1 activities, and place CCR5 as a pharmacological target for cardiovascular outcomes in HA.