Tumor necrosis factor-alpha activates NFkappaB to inhibit renin transcription by targeting cAMP-responsive element.
Tumor necrosis factor-alpha (TNFalpha) is known to inhibit renin gene expression in juxtaglomerular cells, which are the main source of renin in vivo. In the present study we aimed to characterize the intracellular mechanisms of TNFalpha signaling to renin gene in the mouse juxtaglomerular cell line As4.1. TNFalpha was found to activate NFkappaB, which is one of the principal intracellular mediators of TNFalpha signal transduction. Constitutive activation of NFkappaB suppressed renin gene transcription, but NFkappaB appeared not to target the NFkappaB binding sites in the renin promoter. Thus, NFkappaB, but not the canonical NFkappaB binding sequences in the renin promoter, seemed to be involved in the suppression of renin transcription by TNFalpha. Deletion/mutation analysis revealed that the effect of TNFalpha on renin gene is transmitted by a cAMP-responsive element (CRE) located at -2697 to -2690. Mobility shift/supershift assays evidenced for the presence of NFkappaB proteins in the complex that binds to mouse renin CRE. Our results strongly suggest that NFkappaB mediates the effect of TNFalpha on renin transcription targeting a CRE in the mouse renin promoter.
Todorov
Vladimir T
VT
Institute of Physiology, Department of Immunology, Regensburg University, Regensburg D-93040, Germany. vladimir.todorov@vkl.uni-regensburg.de
Völkl
Simon
S
Müller
Markus
M
Bohla
Alexander
A
Klar
Jürgen
J
Kunz-Schughart
Leoni A
LA
Hehlgans
Thomas
T
Kurtz
Armin
A
D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004742:Enhancer Elements, Genetic; D015151:Immunoblotting; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D009154:Mutation; D016328:NF-kappa B / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012313:RNA / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D012083:Renin / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D016328:NF-kappa B; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D012313:RNA; D000242:Cyclic AMP; D008156:Luciferases; D012083:Renin