Regulation of NADPH oxidase subunit p22^phoxby NF-kB in human aortic smooth muscle cells

Abstract

Accumulating evidence demonstrates the involvement of oxidative stress in the pathophysiology of cardiovascular diseases. The molecular mechanisms accountable for the increased production of reactive oxygen species remain uncertain. Among others, NADPH oxidase is one of the most important sources of superoxide in vascular cells. Here we investigate the role of NF-kB in the regulation of p22(phox) subunit and NADPH oxidase activity, in human aortic smooth muscle cells. Overexpression of p65/RelA or IKKbeta up-regulated p22(phox) gene promoter activity. Transcription factor pull-down assays demonstrated the physical interaction of p65/RelA protein with predicted NF-kB binding sites. Real time PCR and Western blotting analysis showed that p22(phox) mRNA and protein expression are significantly down-regulated by NF-kB decoy oligodeoxynucleotides and N-alpha-tosyl-l-phenylalanine chloromethyl ketone (TPCK). Lucigenin-enhanced chemiluminescence assay revealed that NF-kB inhibitors reduce the NADPH-dependent superoxide production. Regulation of NADPH oxidase by NF-kB may represent a possible mechanism whereby pro-inflammatory factors induce oxidative stress in atherosclerosis, hypertension, diabetes, stroke or heart failure.

Vascular Biology of Reactive Oxygen Species and NADPH Oxidases: Role in Atherogenesis

“…Similar finding were reported in human monocytes/macrophages exposed to TNF (Gauss et al, 2007). Moreover, in previous studies we have shown that, NF-kB is an important transcriptional regulator of the genes coding for p22phox, Nox1, and Nox4, and has a profound impact in the up-regulation of Nox activity in TNF -treated human aortic SMCs (Manea et al, 2007;Manea et al, 2010b). The molecular mechanisms that facilitate hypoxia sensing and related signalling events are critical for the maintenance of vascular cell homeostasis.…”

Increased p22phox/Nox4 Expression Is Involved in Remodeling Through Hydrogen Peroxide Signaling in Experimental Persistent Pulmonary Hypertension of the Newborn

“…Nox4 and p22 phox gene expression is regulated by the transcription factor nuclear factor-kappa B (NFjB) (26,28). We quantified levels of the inhibitory protein IjB as an indicator of the NFjB activity in PPHN lungs, and found that IjB protein levels were 52% lower in lung extracts from PPHN lambs relative to control lambs (Fig.…”

Oxidative Stress and Redox-Signaling in Renal Cell Cancer

“…More recent studies suggest that NF-kB upregulates Nox oxidase expression and production of Nox-dependent reactive oxygen species. Here, overexpression of p65/RelA or IKK up-regulated Nox1, Nox4, and p22phox, mRNA, and protein expression through direct binding of the respective promoters (Manea, et al 2007(Manea, et al , 2010. In contrast, NADPHdependent superoxide production (Nox activity) was reduced in the presence of NF-kB inhibitors.…”