Effect of quercetin and catechin on MAPK signaling and coupling of the NADPH oxidase complex

REDONDO ANALIA; ESTRELLA NATALIA; GARCÍA MIRIAM; CRUZADO MONTSERRAT; CASTRO CLAUDIA

San Juan

Congreso; 2º Reunión Conjunta de Sociedades de Biología de la República Argentina; 2011

Previous results from our laboratory showed that the antioxidants quercetin (Q) and catechin (C), present in red wine, reduce angiotensin II (AII)-induce vascular smooth muscle cells (VSMCs) proliferation and migration by inhibiting NADPH oxidase, the main reactive oxygen species generator in the vascular wall. We investigate whether the MAPK signaling pathways activated by AII, Erk1-2 and p38MAPK, are modified by the action of antioxidants. In addition we evaluated if the effect of Q and C is related to the translocation of the protein p47 from the cytosol to the membrane, required for activation of the complex NADPH oxidase. Western blots were performed on extracts of VSMCs derived from spontaneously hypertensive rat. Treatment with AII (10-7M) increased the phosphorylation of both Erk1-2 and p38MAPK. Q, C or their combination had no effect on the activation of Erk1-2. The coincubation of Q (15μM) + C (20μM) significantly inhibited the phosphorylation of p38MAPK and p47 translocation to the cell membrane induced by AII. These results demonstrate that small concentrations of Q and C have a synergistic effect on the inhibition of redox-sensitive signaling pathways. The effect of Q and C is associated with uncoupling of NADPH oxidase, proving to be capable of preventing and/or reverse the vascular changes that occur in hypertension.