Arterial flow reduces oxidative stress via an antioxidant response element and Oct-1 binding site within the NADPH oxidase 4 promoter in endothelial cells
- نوع فایل : کتاب
- زبان : انگلیسی
- مؤلف : Claudia Goettsch Winfried Goettsch Melanie Brux Claudia Haschke Coy Brunssen Gregor Muller Stefan R. Bornstein Nicole Duerrschmidt And
- چاپ و سال / کشور: 2011
Description
The main sources of oxidative stress in the vessel wall are nicotine adenine dinucleotide phosphate (NADPH) oxidase (Nox) complexes. The endothelium mainly expresses the Nox4-containing complex; however, the mechanism by which shear stress in endothelial cells regulates Nox4 is not well understood. This study demonstrates that long-term application of arterial laminar shear stress using a cone-and-plate viscometer reduces endothelial superoxide anion formation and Nox4 expression. In primary human endothelial cells, we identified a 47 bp 50-untranslated region of Nox4 mRNA by 50-rapid amplification of cDNA ends (50-RACE) PCR. Cloning and functional analysis of human Nox4 promoter revealed a range between -1,490 and -1,310 bp responsible for flow-dependent downregulation. Mutation of an overlapping antioxidative response element (ARE)-like and Oct-1 binding site at -1,376 bp eliminated shear stress-dependent Nox4 downregulation. Consistent with these observations, electrophoretic mobility shift assays (EMSA) demonstrated an enhanced shear stress-dependent binding of Nox4 oligonucleotide containing the ARE-like/Oct-1 binding site, which could be inhibited by specific antibodies against the transcription factors nuclear factor erythroid 2-related factor 2 (Nrf2) and octamer transcription factor 1 (Oct-1). Furthermore, shear stress caused the translocation of Nrf2 and Oct-1 from the cytoplasm to the nucleus. Knockdown of Nrf2 by short hairpin RNA (shRNA) increased Nox4 expression twofold, indicating a direct cross-talk between Nrf2 and Nox4. In conclusion, an ARE-like/Oct-1 binding site was noticed to be essential for shear stress-dependent downregulation of Nox4. This novel mechanism may be involved in the flow-dependent downregulation of endothelial superoxide anion formation.
Basic Res Cardiol (2011) 106:551–561 Received: 20 July 2010 / Revised: 15 February 2011 / Accepted: 2 March 2011 / Published online: 12 March 2011
