Oxidative stress and expression of p22phox are involved in the up‐regulation of tissue factor in vascular smooth muscle cells in response to activated platelets

Abstract

Vascular injury after balloon angioplasty results in the rapid activation of platelets leading to the release of growth factors and vasoactive substances. In addition, up-regulation of tissue factor (TF) and an increased production of reactive oxygen species (ROS) have been detected at sites of vascular injury. We investigated whether platelet-derived products (PDP) released from activated human platelets increase ROS production, resulting in the induction of TF expression in vascular smooth muscle cells (SMC). PDP induced a time- and concentration-dependent increase in ROS generation in cultured SMC that was mediated mainly by PDGF-AB and TGF-beta1 and impaired by the flavin inhibitor diphenylene iodonium. Increased ROS formation was associated with enhanced mRNA levels of the small NAD(P)H oxidase subunit p22phox or its smooth muscle isoform. Transient transfection with a p22phox antisense vector decreased PDP-induced ROS generation. PDP up-regulated TF mRNA expression, which was redox sensitive and reduced by transfection of the p22phox antisense vector. In addition, PDP-stimulated reporter gene activity of two TF promoter constructs was decreased by coexpression of the p22phox antisense vector. These results indicate that activated platelets up-regulate TF expression and that this response involves ROS generation and a p22phox-containing NAD(P)H oxidase in SMC.

Antiangiogenic properties of natural polyphenols from red wine and green tea

“…Indeed, exposure of VSMCs to thrombin or PDGF AB caused the generation of substantial amounts of ROS via activation of a p22phox-containing NADPH oxidase [35][36][37]. Moreover, prevention of the generation Fig.…”

“…Red wine polyphenolic compounds inhibit the stimulatory effect of PDGF AB most likely by preventing the formation of intracellular ROS and phosphorylation of p38 MAP kinase. DPI, diphenylene iodonium; NAC, N-acetyl cysteine; Vit C, vitamin C. of ROS by either antioxidant treatments, diphenylene iodonium, a nonselective inhibitor of NADPH oxidase, or p22phox antisense attenuated the expression of VEGF in response to growth factors such as thrombin, PDGF AB and basic fibroblast growth factor (bFGF) [35,36,38]. Reactive oxygen species appear to control the expression of VEGF by activating the heterodimeric transcription factor hypoxiainducible factor-1 [35].…”

In high glucose protein kinase C-ζ activation is required for mesangial cell generation of reactive oxygen species

“…Scrambled sequences for both subunits were used as negative controls. The p22 phox antisense sequence was 5 -GAT CTG CCC CAT GGT GAG GAC C-3 [28]. The p22 phox scrambled sequence was 5 -TAG GCA TAG CCG CTC CGC TGG A-3 .…”

Angiotensin II modulates CD40 expression in vascular smooth muscle cells

“…In another set of experiments, CASMCs were transfected with phosporothioate-modified oligonucleotides against the p22 phox subunit of NADPH oxidase [26]. The oligonucleotides were labelled with fluorescein and transiently transfected into CASMCs by liposomes using the Superfect Transfection Reagent kit (Qiagen), following the manufacturer's instructions.…”