Endothelin-1 induces NAD(P)H oxidase in human endothelial cells

Superoxide anions (O-2(.-)) induce oxidative stress and reduce endothelial NO availability by peroxynitrite formation. In human endothelial cells gp91 (phox) was identified as the limiting subunit of the forming NAD(P)H oxidas e, Because endothelin-1 (ET-1) is considered as a pro-atherosclerotic stimu lus, we analyzed the effect of ET-1 on gp91(phox) expression and O-2(.-) ge neration in primary cultures of human umbilical vein endothelial cells (HUV ECs), The gp91(phox) mRNA expression was quantified by standard calibrated competitive reverse transcriptase-polymerase chain reaction. ET-1 induces g p91(phox) mRNA expression in HUVEC (max, after 1 h), The induction of gp91( phox) expression was dose-dependent, reaching its maximum at 10 nmol/L ET-I , The increased gp91(phox) expression is mediated by endothelial receptor t ype B (ETB). Furthermore, ET-1 augments O-2(.-) generation in human endothe lial cells as measured by coelenterazine chemiluminescence. These data supp ort a new mechanism: how ET-1 increases oxidative stress in the vessel wall leading to endothelial dysfunction and enhanced susceptibility to atherosc lerosis. (C) 2000 Academic Press.