title: Cyclosporin A and tacrolimus induce renal Erk1/2 pathway via ROS-induced and metalloproteinase-dependent EGF-receptor signaling.
abstract: We previously demonstrated that the widely used immunosuppressive drugs cyclosporin A (CsA) and tacrolimus (FK506), independent of immunophilin binding, can activate profibrogenic transforming growth factor β (TGFβ)/Smad signaling cascades in rat renal mesangial cells (MC). Here we report that both peptidyl-prolyl cis/trans isomerase (PPIase) inhibitors activate the extracellular-signaling regulated kinase (ERK) a member of the mitogen activated protein kinase (MAPK) and induce a rapid and transient increase in ERK phosphorylation. The MEK inhibitor U0126, the reactive oxygen species (ROS) scavenger N-acetyl-cysteine (NAC), a cell-permeant superoxide dismutase (SOD) and stigmatellin, an inhibitor of mitochondrial cytochrome bc1 complex strongly attenuated the increase in ERK1/2 phosphorylation triggered by PPIase inhibitors. Moreover, neutralizing antibodies against heparin binding-epidermal growth factor (HB-EGF), and inhibition of the EGF receptor by either small interfering (si)RNA or AG1478, demonstrate that ERK activation by both PPIase inhibitors is mediated via HB-EGF-induced EGF receptor (EGFR) tyrosine kinase activation. The strong inhibitory effects achieved by GM6001 and TAPI-2 furthermore implicate the involvement of a desintegrin and metalloproteinase 17 (ADAM17). Concomitantly, the PPIase inhibitor-induced ADAM17 secretase activity was significantly reduced by SOD and stigmatellin thus suggesting that mitochondrial ROS play a primary role in PPIase inhibitor-induced and ADAM17-mediated HB-EGF shedding. Functionally, both immunosuppressants caused a strong increase in MC proliferation which was similarly impeded when cells were treated in the presence of NAC, TAPI-2 or AG1478, respectively. Our data suggest that CsA and FK506, via ROS-dependent and ADAM17-catalyzed HB-EGF shedding induce the mitogenic ERK1/2 signaling cascade in renal MC.
authors.affiliation: pharmazentrum frankfurt/ZAFES, Klinikum der Johann Wolfgang Goethe-Universität, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany.
authors.forename: El-Sayed
authors.initials: el-S
authors.lastname: Akool
authors.forename: Stefan
authors.initials: S
authors.lastname: Gauer
authors.forename: Bashier
authors.initials: B
authors.lastname: Osman
authors.forename: Anke
authors.initials: A
authors.lastname: Doller
authors.forename: Sebastian
authors.initials: S
authors.lastname: Schulz
authors.forename: Helmut
authors.initials: H
authors.lastname: Geiger
authors.forename: Josef
authors.initials: J
authors.lastname: Pfeilschifter
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Eberhardt
mesh_terms: D051722:ADAM Proteins / Q000378:metabolism; D000072198:ADAM17 Protein; D000818:Animals; D002478:Cells, Cultured; D016572:Cyclosporine / Q000494:pharmacology*; D004790:Enzyme Induction / Q000187:drug effects / Q000502:physiology; D066246:ErbB Receptors / Q000502:physiology*; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D050527:Mesangial Cells / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D045726:Metalloproteases / Q000502:physiology*; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D016559:Tacrolimus / Q000494:pharmacology*
chemical_list: D017382:Reactive Oxygen Species; D016572:Cyclosporine; D066246:ErbB Receptors; D045726:Metalloproteases; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human; C000606464:Adam17 protein, rat; D016559:Tacrolimus