Rho protein-mediated changes in the structure of the actin cytoskeleton regulate human inducible NO synthase gene expression.
Rho proteins (Rho, Rac, Cdc 42) are known to control the organization of the actin cytoskeleton as well as gene expression. Inhibition of Rho proteins by Clostridium difficile toxin B disrupted the F-actin cytoskeleton and enhanced cytokine-induced inducible nitric oxide synthase (iNOS) expression in human epithelial cells. Also specific inhibition by Y-27632 of p160ROCK, which mediates Rho effects on actin fibers, caused a disruption of the actin cytoskeleton and a superinduction of cytokine-induced iNOS expression. Accordingly, direct disruption of the actin cytoskeleton by cytochalasin D, latrunculin B, or jasplakinolide enhanced cytokine-induced iNOS expression. The transcription factor serum response factor (SRF) has been described as mediating actin cytoskeleton-dependent regulation of gene expression. Direct targets of SRF are activating protein 1 (AP1)-dependent genes. All compounds used inhibited SRF- and AP1-dependent reporter gene expression in DLD-1 cells. However, the enhancing effect of the actin cytoskeleton-disrupting compounds on human iNOS promoter activity was much less pronounced than the effect on iNOS mRNA expression. Therefore, besides transcriptional mechanisms, posttranscriptional effects seem to be involved in the regulation of iNOS expression by the above compounds. In conclusion, our data suggest that Rho protein-mediated changes of the actin cytoskeleton negatively modulate the expression of human iNOS.
Witteck
Andrea
A
Department of Pharmacology, Johannes Gutenberg University, Obere Zahlbacher Strasse 67, D-55101, Mainz, Germany.
Yao
Ying
Y
Fechir
Marcel
M
Förstermann
Ulrich
U
Kleinert
Hartmut
H
D008841:Actin Cytoskeleton / Q000187:drug effects / Q000378:metabolism*; D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000494:pharmacology; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D015638:Cytochalasin D / Q000494:pharmacology; D016207:Cytokines / Q000378:metabolism / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism*; D047630:Depsipeptides; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005057:Eukaryotic Cells / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D010456:Peptides, Cyclic / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D026362:Serum Response Factor / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D013844:Thiazoles / Q000494:pharmacology; D053778:Thiazolidines; D018808:Transcription Factor AP-1 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects / Q000235:genetics; D014407:Tumor Cells, Cultured; D020741:rho GTP-Binding Proteins / Q000187:drug effects / Q000378:metabolism*; D054460:rho-Associated Kinases
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D016207:Cytokines; D047630:Depsipeptides; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D010456:Peptides, Cyclic; D012333:RNA, Messenger; D026362:Serum Response Factor; D013844:Thiazoles; D053778:Thiazolidines; D018808:Transcription Factor AP-1; C031815:toxB protein, Clostridium difficile; C057531:jasplakinolide; D015638:Cytochalasin D; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D020741:rho GTP-Binding Proteins; C037068:latrunculin B