Expression of a functionally active gp91phox-containing neutrophil-type NAD(P)H oxidase in smooth muscle cells from human resistance arteries: regulation by angiotensin II.
A major source of vascular smooth muscle cell (VSMC) superoxide is NAD(P)H oxidase. However, the molecular characteristics and regulation of this enzyme are unclear. We investigated whether VSMCs from human resistance arteries (HVSMCs) possess a functionally active, angiotensin II (Ang II)-regulated NAD(P)H oxidase that contains neutrophil oxidase subunits, including p22phox, gp91phox, p40phox, p47phox, and p67phox. mRNA expression of gp91phox homologues, nox1 and nox4, was also assessed in HVSMCs, human aortic smooth muscle cells, and rat VSMCs. HVSMCs were obtained from resistance arteries from gluteal biopsies of healthy subjects. gp91phox and nox4, but not nox1, were detected in HVSMCs. Nox1 and nox4, but not gp91phox, were expressed in human aortic smooth muscle cells and rat VSMCs. All NAD(P)H oxidase subunits were present in HVSMCs as detected by reverse transcriptase-polymerase chain reaction and immunoblotting. Ang II increased NAD(P)H oxidase subunit abundance. These effects were inhibited by cycloheximide. Acute Ang II stimulation (10 to 15 minutes) increased p47phox serine phosphorylation and induced p47phox and p67phox translocation. This was associated with NAD(P)H oxidase activation. In cells transfected with gp91phox antisense oligonucleotides, Ang II-mediated actions were abrogated. NADPH-induced superoxide generation was reduced by gp91ds-tat and apocynin, inhibitors of p47phox-gp91phox interactions. Our results suggest that HVSMCs possess a functionally active gp91phox-containing neutrophil-like NAD(P)H oxidase. Ang II regulates the enzyme by inducing phosphorylation of p47phox, translocation of cytosolic subunits, and de novo protein synthesis. These novel findings provide insight into the molecular regulation of NAD(P)H oxidase by Ang II in HVSMCs. Furthermore, we identify differences in gp91phox homologue expression in VSMCs from rats and human small and large arteries.
Touyz
Rhian M
RM
Multidisciplinary Research Group on Hypertension, Clinical Research Institute of Montreal, University of Montreal, Montreal, Canada. touyzr@ircm.qc.ca
Chen
Xin
X
Tabet
Fatiha
F
Yao
Guoying
G
He
Gang
G
Quinn
Mark T
MT
Pagano
Patrick J
PJ
Schiffrin
Ernesto L
EL
D000328:Adult; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001158:Arteries / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000235:genetics; D026901:Membrane Transport Proteins; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000096:biosynthesis*; D009252:NADPH Dehydrogenase / Q000378:metabolism; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; D009504:Neutrophils / Q000201:enzymology; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011921:Rats, Inbred WKY; D017382:Reactive Oxygen Species / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012694:Serine / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014655:Vascular Resistance
D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D000804:Angiotensin II; D012694:Serine; D009247:NADH, NADPH Oxidoreductases; C056558:CYBB protein, human; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; C086986:CYBA protein, human; C060505:neutrophil cytosolic factor 1; D009252:NADPH Dehydrogenase