Growth-related oncogene-alpha induces endothelial dysfunction through oxidative stress and downregulation of eNOS in porcine coronary arteries.
Growth-related oncogene-alpha (GRO-alpha) is a member of the CXC chemokine family, which is involved in the inflammatory process including atherosclerosis. We hypothesized that GRO-alpha may affect endothelial functions in both porcine coronary arteries and human coronary artery endothelial cells (HCAECs). Vasomotor function was analyzed in response to thromboxane A2 analog U-46619 for contraction, bradykinin for endothelium-dependent vasorelaxation, and sodium nitroprusside (SNP) for endothelium-independent vasorelaxation. In response to 10(-6) M bradykinin, GRO-alpha (50 and 100 ng/ml) significantly reduced endothelium-dependent vasorelaxation by 34.73 and 48.8%, respectively, compared with controls (P < 0.05). There were no changes in response to U-46619 or SNP between treated and control groups. With the lucigenin-enhanced chemiluminescence assay, superoxide anion production in GRO-alpha-treated vessels (50 and 100 ng/ml) was significantly increased by 50 and 86%, respectively, compared with controls (P < 0.05). With real-time PCR analysis, endothelial nitric oxide synthase (eNOS) mRNA levels in porcine coronary arteries and HCAECs after GRO-alpha treatment were significantly decreased compared with controls (P < 0.05). The eNOS protein levels by both immunohistochemistry and Western blot analyses were also decreased in GRO-alpha-treated vessels. Antioxidant seleno-l-methionine and anti-GRO-alpha antibody effectively blocked these effects of GRO-alpha on both porcine coronary arteries and HCAECs. In addition, GRO-alpha immunoreactivity was substantially increased in the atherosclerotic regions compared with nonatherosclerotic regions in human coronary arteries. Thus GRO-alpha impairs endothelium-dependent vasorelaxation in porcine coronary arteries through a mechanism of overproduction of superoxide anion and downregulation of eNOS. GRO-alpha may contribute to human coronary artery disease.
Bechara
Carlos
C
Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX 77030, USA.
Wang
Xinwen
X
Chai
Hong
H
Lin
Peter H
PH
Yao
Qizhi
Q
Chen
Changyi
C
D000818:Animals; D002478:Cells, Cultured; D054360:Chemokine CXCL1 / Q000008:administration & dosage*; D003324:Coronary Artery Disease / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D066298:In Vitro Techniques; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D018384:Oxidative Stress; D013552:Swine
D054360:Chemokine CXCL1; D052250:Nitric Oxide Synthase Type III