title: Activation of NADPH oxidase 1 increases intracellular calcium and migration of smooth muscle cells.
abstract: Redox-dependent migration and proliferation of vascular smooth muscle cells (SMCs) are central events in the development of vascular proliferative diseases; however, the underlying intracellular signaling mechanisms are not fully understood. We tested the hypothesis that activation of Nox1 NADPH oxidase modulates intracellular calcium ([Ca(2+)](i)) levels. Using cultured SMCs from wild-type and Nox1 null mice, we confirmed that thrombin-dependent generation of reactive oxygen species requires Nox1. Thrombin rapidly increased [Ca(2+)](i), as measured by fura-2 fluorescence ratio imaging, in wild-type but not Nox1 null SMCs. The increase in [Ca(2+)](i) in wild-type SMCs was inhibited by antisense to Nox1 and restored by expression of Nox1 in Nox1 null SMCs. Investigation into potential mechanisms by which Nox1 modulates [Ca(2+)](i) showed that thrombin-induced inositol triphosphate generation and thapsigargin-induced intracellular calcium mobilization were similar in wild-type and Nox1 null SMCs. To examine the effects of Nox1 on Ca(2+) entry, cells were either bathed in Ca(2+)-free medium or exposed to dihydropyridines to block L-type Ca(2+) channel activity. Treatment with nifedipine or removal of extracellular Ca(2+) reduced the thrombin-mediated increase of [Ca(2+)](i) in wild-type SMCs, whereas the response in Nox1 null SMCs was unchanged. Sodium vanadate, an inhibitor of protein tyrosine phosphatases, restored the thrombin-induced increase of [Ca(2+)](i) in Nox1 null SMCs. Migration of SMCs was impaired with deficiency of Nox1 and restored with expression of Nox1 or the addition of sodium vanadate. In summary, we conclude that Nox1 NADPH oxidase modulates Ca(2+) mobilization in SMCs, in part through regulation of Ca(2+) influx, to thereby promote cell migration.
authors.affiliation: Jr, University of Iowa, 285 Newton Rd, Room 2269 CBRB, Iowa City, IA 52242, USA.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Zimmerman
authors.forename: Maysam
authors.initials: M
authors.lastname: Takapoo
authors.forename: Dammanahalli K
authors.initials: DK
authors.lastname: Jagadeesha
authors.forename: Bojana
authors.initials: B
authors.lastname: Stanic
authors.forename: Botond
authors.initials: B
authors.lastname: Banfi
authors.forename: Ramesh C
authors.initials: RC
authors.lastname: Bhalla
authors.forename: Francis J
authors.initials: FJ
authors.lastname: Miller
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002465:Cell Movement; D049109:Cell Proliferation; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D005822:Genetic Vectors / Q000235:genetics; D006490:Hemostatics / Q000494:pharmacology; D007295:Inositol Phosphates / Q000378:metabolism; D042541:Intracellular Space / Q000378:metabolism; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D018613:Microscopy, Confocal; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D000074624:NADPH Oxidase 1; D009543:Nifedipine / Q000494:pharmacology; D016376:Oligonucleotides, Antisense / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D013917:Thrombin / Q000494:pharmacology; D014162:Transfection; D014638:Vanadates / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D006490:Hemostatics; D007295:Inositol Phosphates; D016376:Oligonucleotides, Antisense; D017382:Reactive Oxygen Species; D014638:Vanadates; D009247:NADH, NADPH Oxidoreductases; D000074624:NADPH Oxidase 1; C000614711:NOX1 protein, mouse; D013917:Thrombin; D009543:Nifedipine; D002118:Calcium