title: Platelet-derived growth factor triggers PKA-mediated signalling by a redox-dependent mechanism in rat renal mesangial cells.
abstract: Inflammatory glomerular kidney diseases are often accompanied with a massive production of reactive oxygen species (ROS) that affect the function of the glomerular filtration barrier and contribute to mesangiolysis via the induction of cell death in mesangial cells. Intriguingly, ROS also trigger fine-tuned signalling processes that affect gene expression and cell proliferation or migration. To define such redox-driven signalling devices, a proteomics approach was performed to identify the formation of protein complexes induced by ROS. To this end, protein lysates of human podocytes were treated with or without hydrogen peroxide (250 μM). Thereafter cell lysates were subjected to diagonal 2D gel electrophoresis and putative redox-affected proteins were analysed by MS/MS analysis. Among others, the regulatory subunit of protein kinase A (PKA) could be identified that forms homodimers under oxidative conditions. To evaluate whether ROS dependent dimerization of PKA also occurs in a more physiological setting, rat mesangial cells were treated with platelet-derived growth factor-BB (PDGF-BB) to induce ROS formation. This regimen resulted in a redox dependent dimerization of the R-subunits of PKA. To demonstrate whether PDGF-BB induced ROS formation affects PKA dependent pathways, the effects of PDGF-BB on phosphorylation of serine 157 of vasodilator stimulated protein (VASP) a classical target of PKA were analysed. Interestingly PDGF-BB induced VASP phosphorylation in a ROS dependent manner but independent of changes in cAMP levels. Taken together, we demonstrate a redox-mediated activation of PKA by PDGF-BB thus highlighting a physiological role of ROS as regulator of PKA activity in rat mesangial cells.
authors.affiliation: Pharmazentrum Frankfurt/ZAFES, Klinikum der Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Eisel
authors.forename: Meike
authors.initials: M
authors.lastname: Boosen
authors.forename: Martina
authors.initials: M
authors.lastname: Beck
authors.forename: Heinrich
authors.initials: H
authors.lastname: Heide
authors.forename: Ilka
authors.initials: I
authors.lastname: Wittig
authors.forename: Karl-Friedrich
authors.initials: KF
authors.lastname: Beck
authors.forename: Josef
authors.initials: J
authors.lastname: Pfeilschifter
mesh_terms: D000818:Animals; D000077214:Becaplermin; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D050527:Mesangial Cells / Q000187:drug effects / Q000378:metabolism*; D008840:Microfilament Proteins / Q000378:metabolism; D010084:Oxidation-Reduction; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D050199:Podocytes / Q000378:metabolism; D055503:Protein Multimerization; D021122:Protein Subunits / Q000378:metabolism; D040901:Proteomics; D020574:Proto-Oncogene Proteins c-sis / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D012694:Serine / Q000378:metabolism; D015398:Signal Transduction; D000098662:Vasodilator-Stimulated Phosphoprotein
chemical_list: D015815:Cell Adhesion Molecules; D008840:Microfilament Proteins; D010750:Phosphoproteins; D021122:Protein Subunits; D020574:Proto-Oncogene Proteins c-sis; D017382:Reactive Oxygen Species; D000098662:Vasodilator-Stimulated Phosphoprotein; D000077214:Becaplermin; D012694:Serine; D006861:Hydrogen Peroxide; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases