Abstract P280: CCL5 Causes Vascular Injury Via CCR5 And Nadph Oxidase 1- Derived Ros
Chemokine (C-Cmotif) ligand 5 (CCL5) and its receptor CCR5 belong to the family of chemokines and are expressed and active in the vasculature. NADPH oxidases (Noxs) are the major source of reactive oxygen species (ROS) in vascular cells, but whether the activation of these oxidases is CCL5/CCR5 sensitive and whether such interaction participates in the genesis of vascular disease is not fully known. We investigated whether CCL5/CCR5 leads to vascular injury by activating Nox1. Carotid ligation model (CL, for 2-weeks) was used to induce pathological vascular growth in 10-weeks old (C57BL6/J) mice. Rat aortic smooth muscle cells (RASMC) were treated with recombinant CCL5 (100ng/mL) to study the molecular mechanisms. CL induces neointima formation, which was associated with increase in IL1β, TNFα, CCR3, CCR5 (3-fold increase), CCL5, and Nox1 gene expression. No difference was observed for Nox2 and 4. Treatment with CCR5 blocker (maraviroc, 25mg/Kg/day i.p) partially inhibited CL-induced vascular injury (media/intima ratio, CL: 1.2 ± 0.2 vs CL + maraviroc: 0.7 ± 0.2) and Nox1 expression (Fold changes: CL: 2.1 ± 0.4 vs CL + maraviroc: 1.2 ± 0.4). In RASMC, CCL5 induced Nox1 expression, which was blunted by pre-treating cells with maraviroc (10uM). Also, it increases p47phox content in membrane fraction (index of Nox activation), and elevated ROS production, analyzed by L012. CCL5 also induced cell migration, measured by transwell assay (number of cells per spot, control: 21.3 ± 3.1 vs CCL5: 31.1 ± 2.4), proliferation, analyzed by Edu+ cells (% of cells per spot, control: 10.6 ± 4.3 vs CCL5: 22.8 ± 5.1), and inflammation (studied by IL1β and TNFα levels). Lastly, CCL5 elevated NF-κB translocation into the nucleus, indicating NF-κB activation. Strikingly, inhibition of Nox1 (GKT771, 10uM), blocked CCL5-induced vascular migration, proliferation, and inflammation, as well as NF-κB activation. We propose that CCL5 activates Nox1 in the vasculature leading to local injury characterized by vascular inflammation and cellular migration and proliferation, perhaps by activating NF-κB signaling. Herein, we place CCR5 signaling as possible therapeutic target to reduce the cardiovascular risk in inflammatory diseases associated with dysregulation of CCL5 and/or CCR5