Mechanisms of NOS2 regulation by Rho GTPase signaling in airway epithelial cells.
The aberrant dysregulation of the inducible form of nitric oxide synthase (NOS2) is thought to play a role in many inflammatory disorders including cystic fibrosis (CF). The complex regulation of NOS2 expression is the subject of intense investigation, and one intriguing regulatory pathway known to influence NOS2 expression is the Rho GTPase cascade. We examined NOS2 regulation in response to inflammatory cytokines in a human alveolar epithelial cell line treated with inhibitors of different upstream and downstream components of the Rho GTPase pathway to better define potential signaling mechanisms. Statin-mediated 3-hydroxy-3-methylglutaryl-CoA reductase inhibition increased cytokine-dependent activation of the NOS2 promoter, reversible by the addition of geranylgeranyl pyrphosphate. However, inhibition of Rho-associated kinase (ROCK) with Y-27632 resulted in a decrease in NOS2 promoter activity, yet an increase in NOS2 mRNA and protein levels. Our results suggest that prenylation events influence NOS2 promoter activity independently of the Rho GTPase pathway and that Rho GTPase signaling mediated through ROCK suppresses NOS2 production downstream of promoter function at the message and protein level.
Kraynack
Nathan C
NC
Department of Pediatrics, Case Western Reserve University and Rainbow Babies and Children's Hospital, Cleveland, Ohio 44106-4948, USA.
Corey
Deborah A
DA
Elmer
Heather L
HL
Kelley
Thomas J
TJ
D000577:Amides / Q000494:pharmacology; D004122:Dimethylallyltranstransferase / Q000037:antagonists & inhibitors; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000201:enzymology; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D008148:Lovastatin / Q000031:analogs & derivatives* / Q000494:pharmacology; D016328:NF-kappa B / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D011401:Promoter Regions, Genetic / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000494:pharmacology; D011650:Pulmonary Alveoli / Q000166:cytology / Q000201:enzymology*; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014407:Tumor Cells, Cultured; D020741:rho GTP-Binding Proteins / Q000502:physiology*; D054460:rho-Associated Kinases
D000577:Amides; D004791:Enzyme Inhibitors; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D016328:NF-kappa B; D011725:Pyridines; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; C108830:Y 27632; C012258:mevastatin; D008148:Lovastatin; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D004122:Dimethylallyltranstransferase; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D020741:rho GTP-Binding Proteins