Vanadate induction of NF-kappaB involves IkappaB kinase beta and SAPK/ERK kinase 1 in macrophages.
The present studies investigated the signaling pathways of vanadate, a vanadium ion with +5 oxidation state, to activate NF-kappaB transcription factor, a pivotal regulator of inflammatory responses. Treatment of macrophages with vanadate results in the activation of both NF-kappaB and c-Jun N-terminal kinase (JNK). The activity of a recently identified cellular kinase, IkappaB kinase-beta (IKKbeta), was significantly elevated concomitant with the increased degradation of IkappaBalpha and enhanced NF-kappaB activity in cells exposed to vanadate. To determine whether the IKK pathway and JNK pathway are interconnected or bifurcate upon vanadate stimulation, cells were transfected with either a kinase inactive form of IKKbeta or a kinase inactive form of SAPK/ERK kinase 1 (SEK1). Inactive IKKbeta was able to block vanadate-induced degradation of IkappaBalpha, yet it was unable to influence the activation of JNK by vanadate. Conversely, blockage of JNK activation by transfection of a kinase-inactive form of SEK1 resulted in partially inhibition of vanadate-induced IkappaBalpha degradation. Both vanadate-induced degradation of IkappaBalpha and activation of JNK were potently inhibited by pretreatment of cells with N-acetylcysteine or dimercaprol. These results demonstrate that early activation of stress kinases or change of cellular redox states plays a key role in vanadate-induced activation of NF-kappaB and JNK.
Chen
F
F
Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia 26505, USA.
Demers
L M
LM
Vallyathan
V
V
Ding
M
M
Lu
Y
Y
Castranova
V
V
Shi
X
X
D000818:Animals; D002460:Cell Line; D004789:Enzyme Activation; D051550:I-kappa B Kinase; D048670:MAP Kinase Kinase 4; D008264:Macrophages / Q000201:enzymology*; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases; D016328:NF-kappa B / Q000096:biosynthesis*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism; D014638:Vanadates / Q000494:pharmacology*
D016328:NF-kappa B; D014638:Vanadates; D014443:Tyrosine; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; C496564:Chuk protein, mouse; D051550:I-kappa B Kinase; C496562:Ikbkb protein, mouse; C496566:Ikbke protein, mouse; D048670:MAP Kinase Kinase 4; C482562:Map2k4 protein, mouse; D020929:Mitogen-Activated Protein Kinase Kinases