Tumor necrosis factor-alpha (TNF-alpha) induces upregulation of RhoA via NF-kappaB activation in cultured human bronchial smooth muscle cells.
RhoA plays an important role in Ca(2+) sensitization of bronchial smooth muscle in antigen-induced airway hyperresponsiveness (AHR). Tumor necrosis factor-alpha (TNF-alpha), a major proinflammatory cytokine, is capable of inducing AHR, but the mechanisms for this are still unknown. In the present study, the effect of TNF-alpha on RhoA protein expression was examined in cultured human bronchial smooth muscle cells (hBSMCs). To investigate the role of NF-kappaB in the TNF-alpha-induced upregulation of RhoA, the effects of an inhibitor of IkappaB kinase (IKK), BMS-345541, were also determined. Both immunoblot and immunocytochemical analyses revealed that incubation of the hBSMCs with TNF-alpha caused an activation of NF-kappaB (determined by a translocation of p65 proteins to nuclei): the peak response was observed when cells were incubated with 10 ng/mL of TNF-alpha for 30 min. An upregulation of RhoA protein was also observed at 12 - 24 h after the incubation with TNF-alpha (10 ng/mL). Both the activation of NF-kappaB and upregulation of RhoA were concentration-dependently inhibited by the co-incubation with BMS-345541. These results suggest that TNF-alpha-induced upregulation of RhoA might be mediated by an activation of NF-kappaB in hBSMCs.
Goto
Kumiko
K
Department of Pharmacology, School of Pharmacy, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, Japan.
Chiba
Yoshihiko
Y
Sakai
Hiroyasu
H
Misawa
Miwa
M
D001980:Bronchi / Q000166:cytology / Q000378:metabolism; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage / Q000494:pharmacology; D015151:Immunoblotting; D007150:Immunohistochemistry; D032389:Myocytes, Smooth Muscle / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism*; D011810:Quinoxalines / Q000008:administration & dosage / Q000494:pharmacology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism* / Q000494:pharmacology; D015854:Up-Regulation; D020742:rhoA GTP-Binding Protein / Q000235:genetics* / Q000378:metabolism
C471109:4(2'-aminoethyl)amino-1,8-dimethylimidazo(1,2-a)quinoxaline; D007093:Imidazoles; D016328:NF-kappa B; D011810:Quinoxalines; D014409:Tumor Necrosis Factor-alpha; D020742:rhoA GTP-Binding Protein