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Nox4 overexpression activates reactive oxygen species and p38 MAPK in human endothelial cells

Claudia Goettsch1, Winfried Goettsch, Gregor Muller

  • 1Division of Vascular Endothelium and Microcirculation, Department of Medicine III, University of Technology Dresden, Fetscherstr. 74, D-01307 Dresden, Germany.

Biochemical and Biophysical Research Communications
|March 13, 2009
PubMed

Insights

Nicotine adenine dinucleotide phosphate (NADPH) oxidase 4 (Nox4) is the primary source of reactive oxygen species (ROS) in human endothelial cells. Nox4 activation by p22(phox) triggers signaling pathways, impacting vascular health.

Area of Science:

  • Vascular Biology
  • Cell Signaling
  • Oxidative Stress

Background:

  • NADPH oxidase (Nox) complexes generate reactive oxygen species (ROS) in the vessel wall.
  • Understanding Nox isoform roles in endothelial cells is crucial for vascular health.

Purpose of the Study:

  • To identify the major Nox isoform in human endothelial cells.
  • To investigate the role of Nox4 in ROS production and signaling.

Main Methods:

  • DNA microarray, real-time PCR, and Western blot analyses.
  • Laser scanning confocal microscopy for protein localization.
  • Gene silencing (shRNA) and overexpression studies.

Main Results:

  • Nox4 identified as the major Nox isoform in human endothelial cells.
  • High expression of p22(phox) observed, forming an active complex with Nox4.
  • Nox4 overexpression increased superoxide anion formation and p38 MAPK phosphorylation.
  • Nox4 down-regulation did not affect p38 MAPK phosphorylation, unlike TGF-beta.

Conclusions:

  • Nox4 is the predominant Nox isoform in human endothelial cells, partnering with p22(phox).
  • The Nox4-p22(phox) complex is a key mediator of ROS production and p38 MAPK activation.
  • This represents a novel redox-sensitive signaling pathway in human endothelial cells.

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