Synthesis and function of redox mediators in glomerular mesangial cells
K.-F. Beck (group leader), M. Beck, U. Schmidt
Inflammatory processes are accompanied with a delicate interplay of different resident or invading cells that communicate each other via the production of inflammatory mediators such as cytokines, chemokines or prostaglandins. During the last decades, there was emerging evidence that short-lived inorganic molecules such as nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H2S), recently referred to as gasotransmitters together with reactive oxygen species (ROS) are endogenously synthesized in an inflammatory setting and trigger fine-tuned signalling devices that influence various cellular processes such as proliferation, migration or apoptosis. Moreover, the gasotransmitters mentioned above as well as ROS potently affect the gene transcription pattern under inflammatory conditions. ROS, NO and H2S potently react with thiols of cysteines by forming sulfenic acid or the higher oxidized forms sulfinic and sulfonic acid (by ROS), nitrosothiols (by NO) and hydropersulfides (by H2S). These modifications also referred to as thiol-based redox switches often result in an altered activity of the affected enzymes. Therefore, the importance of cysteine modifications on signalling processes is nowadays regarded as comparable to the role of phosphorylation cascades. Moreover, the tightly controlled regulation of ROS, NO, H2S and CO synthesizing enzymes may further serve for a high temporal and spatial diversity of the composition of these highly reactive inorganic molecules within a cell in particular in an inflammatory setting. To elucidate this complex redox-dependent interplay, we focus firstly on the regulation of redox-mediators in cultured glomerular mesangial cells, cultured podocytes and in animal models for glomerulonephritis. Secondly, we analyse redox-mediated thiol switches by using redox proteomic approaches and biotin switch assay-based techniques.
Our work is supported by the Deutsche Forschungsgemeinschaft (Sonderforschungsbereich 815). Furthermore, in particular in the field of H2S signalling, we participate in the European Network on Gasotransmitters (COST Action BM1005, ENOG). To analyse the actions of ROS, H2S and NO on gene expression in mesangial cells we cooperate with the groups of J. Pfeilschifter and W. Eberhardt. In cooperation with L. Schaefer, we transfer our data obtained from the cell culture model to suitable inflammatory animal models.
Pfeilschifter J, Beck, KF (2011) Oxidative Stress Injury in Glomerular Mesangium in „Studies on Renal Disorders: Series: Oxidative Stress in Applied Basic Research and Clinical Practice”. Eds. Miyata T, Eckardt KU; Nangaku M Humana Press, 3-24.
Hassan MI, Boosen M, Schaefer L, Kozlowska J, Eisel F, von Knethen A, Beck M, Hemeida RA, El-Moselhy MA, Hamada FM, Beck KF, Pfeilschifter J (2012) Platelet-derived growth factor-BB induces cystathionine ?-lyase expression in rat mesangial cells via a redox-dependent mechanism. Br J Pharmacol. 166:2231-2242.
Eisel F, Boosen M, Beck M, Heide H, Wittig I, Beck KF, Pfeilschifter J (2013) Platelet-derived growth factor triggers PKA-mediated signalling by a redox-dependent mechanism in rat renal mesangial cells. Biochem Pharmacol. 85:101-108.
Redox regulation of gene expression
J. Pfeilschifter (group leader), S. Schwalm,
Were are interested in the effects of reactive oxygen species (ROS) such as superoxide anion, hydrogen peroxide, nitric oxide, peroxynitrite and hypoxia on gene regulatory events in inflammatory diseases.
We use several experimental in vitro models (glomerular endothelial cells, mesangial cells, macrophages and MCF-7) as well as experimental in vivo models of renal inflammation (endotoxaemia, Thy1.1 glomerulonephritis, haemorrhagic shock, and MRL/lpr autoimmune glomerulonephritis) to investigate the impact of ROS on:
a) the two major cellular redox homeostasis regulators: the glutathione and thioredoxin systems
b) the eicosanoid biosynthetic cascade comprising phospholipases A2, cyclooxygenases and
diverse prostaglandin synthases
These projects are pursued in close collaboration with the groups of Karl-Friedrich Beck, Wolfgang Eberhardt and Andrea Huwiler.