Ulrich Sydlik

Publications (9)47.01 Total impact

• Article: Carbon nanoparticles induce ceramide- and lipid raft-dependent signalling in lung epithelial cells: a target for a preventive strategy against environmentally-induced lung inflammation.

  Henrike Peuschel, Ulrich Sydlik, Susanne Grether-Beck, Ingo Felsner, Daniel Stöckmann, Sascha Jakob, Matthias Kroker, Judith Haendeler, Marijan Goti, Christiane Bieschke, Jean Krutmann, Klaus Unfried
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  ABSTRACT: BACKGROUND: Particulate air pollution in lung epithelial cells induces pathogenic endpoints like proliferation, apoptosis, and pro-inflammatory reactions. The activation of the epidermal growth factor receptor (EGFR) is a key event responsible for signalling events involving mitogen activated protein kinases specific for these endpoints. The molecular events leading to receptor activation however are not well understood. These events are relevant for the toxicological evaluation of inhalable particles as well as for potential preventive strategies in situations when particulate air pollution cannot be avoided. The current study therefore had the objective to elucidate membrane-coupled events leading to EGFR activation and the subsequent signalling cascade in lung epithelial cells. Furthermore, we aimed to identify the molecular target of ectoine, a biophysical active substance which we described to prevent carbon nanoparticle-induced lung inflammation. METHODS: Membrane signalling events were investigated in isolated lipid rafts from lung epithelial cells with regard to lipid and protein content of the signalling platforms. Using positive and negative intervention approaches, lipid raft changes, subsequent signalling events, and lung inflammation were investigated in vitro in lung epithelial cells (RLE-6TN) and in vivo in exposed animals. RESULTS: Carbon nanoparticle treatment specifically led to an accumulation of ceramides in lipid rafts. Detailed analyses demonstrated a causal link of ceramides and subsequent EGFR activation coupled with a loss of the receptor in the lipid raft fractions. In vitro and in vivo investigations demonstrate the relevance of these events for carbon nanoparticle-induced lung inflammation. Moreover, the compatible solute ectoine was able to prevent ceramide-mediated EGFR phosphorylation and subsequent signalling as well as lung inflammation in vivo. CONCLUSION: The data identify a so far unknown event in pro-inflammatory signalling and contribute to the understanding of particle cell interaction and therefore to risk identification and risk assessment of inhalable xenobiotics. Moreover, as this cellular reaction can be prevented by the well tolerated substance ectoine, a molecular preventive strategy for susceptible persons against airway inflammation is proposed.
  Particle and Fibre Toxicology 12/2012; 9(1):48. · 7.25 Impact Factor
• Article: Recovery of neutrophil apoptosis by ectoine: a new strategy against lung inflammation.

  Ulrich Sydlik, Henrike Peuschel, Adnana Paunel-Görgülü, Stefanie Keymel, Ursula Krämer, Alexander Weissenberg, Matthias Kroker, Samira Seghrouchni, Christian Heiss, Joachim Windolf, Andreas Bilstein, Malte Kelm, Jean Krutmann, Klaus Unfried
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  ABSTRACT: The life span of neutrophilic granulocytes has determining impact on the intensity and duration of neutrophil driven lung inflammation. Based on the compatible solute ectoine, we aimed to prevent anti-apoptotic reactions in neutrophils triggered by the inflammatory microenvironment in the lung.Neutrophils from COPD patients and control individuals were exposed to inflammatory mediators and xenobiotics in the presence or absence of ectoine. The in vivo relevance of this approach was tested in xenobiotic-induced lung inflammation in rats.The reduction of apoptosis rates of ex vivo exposed neutrophils from persons of all study groups was significantly restored in the presence of ectoine. However, natural apoptosis rates not altered by inflammatory stimuli were not changed by ectoine. Mechanistic analyses demonstrated the preventive effect of ectoine on the induction of anti-apoptotic signalling. Neutrophilic lung inflammation induced by single or multiple exposition of animals to environmental particles was reduced after the therapeutic intervention with ectoine. Analyses of neutrophils from bronchoalveolar lavage indicate that the in vivo effect is due to the restoration of neutrophil apoptosis.Ectoine, a compound of the highly compliant group of compatible solutes, demonstrates a reproducible and robust effect on the resolution of lung inflammation.
  European Respiratory Journal 10/2012; · 5.89 Impact Factor
• Article: Unhealthy diet and ultrafine carbon black particles induce senescence and disease associated phenotypic changes.

  Nicole Büchner, Niloofar Ale-Agha, Sascha Jakob, Ulrich Sydlik, Kerstin Kunze, Klaus Unfried, Joachim Altschmied, Judith Haendeler
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  ABSTRACT: Diet and pollution are environmental factors known to compromise "healthy aging" of the cardiovascular and respiratory systems. The molecular consequences of this permanent burden in these cells are still unknown. Therefore, this study investigates the impact of unhealthy diet on aging-related signaling pathways of human, primary cardiovascular cells and of airborne particles on lung epithelial and human endothelial cells. Nutrition health reports have shown that the diet in industrialized countries contains more than 100mg/dl low density lipoprotein (LDL) and a high fraction of added sugars, especially fructose. Several studies demonstrated that ultrafine particles can enter the circulation and thus may interact with endothelial cells directly. Both, dietary compounds and pollution derived particles, have been shown to increase the risk for cardiovascular diseases. To simulate an unhealthy diet, we supplemented cell culture media of human primary endothelial cells, smooth muscle cells and cardiomyocytes with LDL and replaced 1/3 of glucose with fructose. We observed hypertrophy in cardiomyocytes, enhanced proliferation in smooth muscle cells and increased senescence, loss of endothelial nitric oxide synthase and increased nuclear FoxO3A in endothelial cells. With respect to pollution we have used ultrafine carbon black particles (ufCB), one of the major constituents of industrial and exhaust emissions, in concentrations our lungs and vessels are constantly exposed to. These concentrations of ufCB increased reactive oxygen species in lung epithelial and vascular endothelial cells and reduced the S-NO content, a marker for NO-bioavailability, in endothelial cells. NO increases activation of Telomerase Reverse Transcriptase (TERT), an enzyme essential for telomere maintenance. TERT is required for proper endothelial cell function and is inactivated by Src kinase under conditions of oxidative stress. ufCB significantly increased Src kinase activation and reduced Telomerase activity in endothelial and lung epithelial cells. As a consequence, ufCB increased senescence of endothelial cells. To investigate whether ufCB show also effects in vivo, we instilled ufCB in concentrations not inducing inflammation into mice. Indeed, eNOS expression was reduced in the abdominal aorta of animals treated with ufCB. Thus, a combination of fructose and LDL in the diet and ufCB, as a major constituent of air pollution, seem to accelerate respiratory and cardiovascular cellular changes, which may compromise "healthy aging" and can lead to cardiovascular and pulmonary diseases.
  Experimental gerontology 04/2012; · 3.34 Impact Factor
• Article: c-Src-mediated activation of Erk1/2 is a reaction of epithelial cells to carbon nanoparticle treatment and may be a target for a molecular preventive strategy.

  Henrike Peuschel, Ulrich Sydlik, Judith Haendeler, Nicole Büchner, Daniel Stöckmann, Matthias Kroker, Ragnhild Wirth, Winfried Brock, Klaus Unfried
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  ABSTRACT: Owing to their specific physico/chemical properties, engineered as well as environmental nanoparticles can induce pathogenic endpoints in humans. Earlier studies demonstrated that pure carbon nanoparticles induce cell signaling events at the level of membrane receptor activation in lung epithelial cells. As a possible link between receptor activation and subsequent MAP-kinase signaling, the involvement of Src family kinases was investigated in cell lines of organs potentially exposed to environmental nanoparticles. Human cells from bronchus, intestine, and skin (keratinocytes) as well as rat lung epithelial cells showed similar time patterns for the activation of mitogen-activated protein kinases Erk1/2 as well as Src family kinases (SFK) when treated with carbon nanoparticles. Moreover, c-Src was identified as an integral part of the signaling mediating the transfer of information from membrane receptors to members of the proliferative signaling cascade in lung epithelial cells. Pretreatment of cells with the compatible solute ectoine, which is known to stabilize macromolecules, reduced the nanoparticle specific phosphorylation of SFK. Together with earlier in vivo and in vitro data, this demonstrates that compatible solutes prevent nanoparticle-induced signaling steps at the level of membrane-coupled signaling.
  Biological Chemistry 11/2010; 391(11):1327-32. · 2.96 Impact Factor
• Article: Reactive oxygen species as mediators of membrane-dependent signaling induced by ultrafine particles.

  Alexander Weissenberg, Ulrich Sydlik, Henrike Peuschel, Peter Schroeder, Maren Schneider, Roel P F Schins, Josef Abel, Klaus Unfried
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  ABSTRACT: Cell-membrane-dependent proliferative signal transduction activated by ultrafine carbon particles in lung epithelial cells involves the specific induction of Akt and ERK1/2 phosphorylation. Particle-induced generation of reactive oxygen species (ROS) and oxidative stress are regarded as initial molecular mechanisms leading to the induction of diverse cellular responses. Therefore, we aimed to analyze the ROS dependence of the induced activation of the Akt/ERK1/2 signaling pathway upon exposure to ultrafine particulate matter (UPM). For this, ultrafine carbon black (ufCB) and ferric sulfate (FS) were used as a model representing the carbonaceous core and a nonparticulate Fenton-reactive transition metal salt often found in combustion-derived UPM. Cell-free as well as intracellular particle-induced ROS generation was assessed and related to the induced Akt and ERK1/2 phosphorylation by inhibiting oxidative stress with catalase, superoxide dismutase, and N-acetylcysteine. We show here that the activation of this signal transduction pathway was mainly due to intracellular, rather than extracellular, ROS production induced by both ufCB and FS. Further inhibitor studies on the role of cell membrane receptors pointed to the epidermal growth factor receptor as a common mediator for particle- as well as transition metal-induced signaling, whereas integrin-dependent Akt and ERK1/2 activation seems to be particle-specific.
  Free radical biology & medicine 08/2010; 49(4):597-605. · 5.42 Impact Factor
• Article: The compatible solute ectoine protects against nanoparticle-induced neutrophilic lung inflammation.

  Ulrich Sydlik, Inka Gallitz, Catrin Albrecht, Josef Abel, Jean Krutmann, Klaus Unfried
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  ABSTRACT: Inflammatory reactions of the airways induced by nanoparticles of occupational and environmental origin contribute to organ-specific and systemic human diseases. Because this kind of exposure in modern societies is often unavoidable, a strategy of molecular prevention on an individual level could help to prevent inflammation-derived secondary diseases. To test whether the compatible solute ectoine [(S)-2-methyl-1,4,5,6-tetrahydropyrimidine-4-carboxylic acid], which is known to reduce cell stress effects on a molecular level, prevents nanoparticle-induced lung inflammation. Inflammatory parameters were studied in Fischer 344 rats treated with model carbon nanoparticles. The molecular effects of ectoin on proinflammatory signal transduction were demonstrated in the rat and in the human system using cultured lung epithelial cells. Ectoine, given with or before the nanoparticles, dose-dependently reduced neutrophil inflammation in the lung. This preventive effect was not observed when lung inflammation was induced by bacterial lipopolysaccharide. Analyses of the underlying mode of action revealed that ectoine acted on lung epithelial cells. Ectoine administration inhibited nanoparticle-induced signaling, which is known to be responsible for proinflammatory reactions in rat lung epithelial cells in vitro as well as in vivo. These findings were corroborated and extended in experiments with cultured human bronchial epithelial cells in which ectoine inhibited nanoparticle-triggered cell signaling and IL-8 induction. Because compatible solutes are compliant natural products without known toxic potential, we propose that this group of substances may be used for the prevention of particle-induced airway inflammation in humans.
  American Journal of Respiratory and Critical Care Medicine 04/2009; 180(1):29-35. · 11.08 Impact Factor
• Article: Carbon nanoparticle-induced lung epithelial cell proliferation is mediated by receptor-dependent Akt activation.

  Klaus Unfried, Ulrich Sydlik, Katrin Bierhals, Alexander Weissenberg, Josef Abel
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  ABSTRACT: Treatment of lung epithelial cells with different kinds of nano-sized particles leads to cell proliferation. Because bigger particles fail to induce this reaction, it is suggested that the special surface properties, due to the extremely small size of these kinds of materials, is the common principle responsible for this specific cell reaction. Here the activation of the protein kinase B (Akt) signaling cascade by carbon nanoparticles was investigated with regard to its relevance for proliferation. Kinetics and dose-response experiments demonstrated that Akt is specifically activated by nanoparticulate carbon particles in rat alveolar type II epithelial cells as well as in human bronchial epithelial cells. This pathway appeared to be dependent on epidermal growth factor receptor and beta(1)-integrins. The activation of Akt by these receptors is known to be a feature of adhesion-dependent signaling. However, intracellular proteins described in this context (focal adhesion kinase pp125(FAK) and integrin-linked kinase) were not activated, indicating a specific signaling mechanism. Inhibitor studies demonstrate that nanoparticle-induced proliferation is mediated by phosphoinositide 3-kinases and Akt. Moreover, overexpression of mutant Akt, as well as pretreatment with an Akt inhibitor, reduced nanoparticle-specific ERK1/2 phosphorylation, which is decisive for nanoparticle-induced proliferation. With this report, we describe the activation of a pathway by carbon nanoparticles that was so far known to be triggered by ligand receptor binding or on cell adhesion to extracellular matrix proteins.
  AJP Lung Cellular and Molecular Physiology 03/2008; 294(2):L358-67. · 3.66 Impact Factor
• Article: Analysis of the transcriptional regulation and molecular function of the aryl hydrocarbon receptor repressor in human cell lines.

  Thomas Haarmann-Stemmann, Hanno Bothe, Amitabh Kohli, Ulrich Sydlik, Josef Abel, Ellen Fritsche
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  ABSTRACT: The aryl hydrocarbon receptor repressor (AhRR) is a member of the aryl hydrocarbon receptor (AhR) signaling cascade, which mediates dioxin toxicity and is involved in regulation of cell growth and differentiation. The AhRR was described as a feedback modulator, which counteracts AhR-dependent gene expression. We investigated the molecular mechanisms of transcriptional regulation of the human AhRR by cloning its regulatory DNA region located in intron I of the AhRR. By means of reporter gene analyses and generation of deletion variants, we identified a functional, 3-methylcholanthrene-sensitive xenobiotic response element (XRE) site. Chromatin immunoprecipitation analyses revealed that the AhRR binds to this XRE, displaying an autoregulatory loop of AhRR expression. In addition we show that an adjacent GC-box is of functional relevance for AhRR transcription, since blocking of this GC-box resulted in a decrease of constitutive and inducible AhRR gene activity. The differences in constitutive AhRR mRNA level observed in HepG2, primary fibroblast, and HeLa cells are directly correlated with CYP1A1 inducibility. We show that the nonresponsiveness of high AhRR-expressing cells toward AhR-agonists is associated with a constitutive binding of the AhRR to XRE sites of CYP1A1. Treatment with the histone deacetylase inhibitor sodium butyrate restored the responsiveness of CYP1A1 in these cell lines, due to the dissociation of AhRR from the XREs. Furthermore, transient AhRR mRNA silencing in untreated HeLa cells was accompanied by an increase of basal CYP1A1 expression, pointing to a constitutive role of the AhRR in regulation of CYP1A1. The functional relevance of the AhRR in high AhRR-expressing primary fibroblasts is discussed.
  Drug Metabolism and Disposition 01/2008; 35(12):2262-9. · 3.73 Impact Factor
• Article: Ultrafine carbon particles induce apoptosis and proliferation in rat lung epithelial cells via specific signaling pathways both using EGF-R.

  Ulrich Sydlik, Katrin Bierhals, Maria Soufi, Josef Abel, Roel P F Schins, Klaus Unfried
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  ABSTRACT: Apoptosis and proliferation are important causes of adverse health effects induced by inhaled ultrafine particles. The molecular mechanisms of particle cell interactions mediating these end points are therefore a major topic of current particle toxicology and molecular preventive medicine. Initial studies revealed that ultrafine particles induce apoptosis and proliferation in parallel in rat lung epithelial cells, dependent on time and dosage. With these end points, two antagonistic reactions seem to be induced by the same extracellular stimulus. It was therefore investigated whether proliferation is induced directly by the particles or as a compensation of particle-caused cell death. Experimental conditions excluding compensatory proliferation demonstrated that both end points are induced independently by specific signaling pathways. Events eliciting signaling cascades leading to apoptosis and proliferation were studied with specific inhibitors of membrane receptors. Epidermal growth factor receptor (EGF-R) kinase activity was identified as essential for apoptosis as well as for proliferation. As ultrafine particle-induced proliferation alone was dependent on the activation of beta1-integrins, these membrane receptors are suggested to mediate the specificity of EGF-R signaling concerning the decision as to whether apoptosis or proliferation is triggered. Accordingly, MAP kinase signaling downstream of EGF-R showed comparable specificity with regard to receptor-dependent induction of apoptosis and proliferation. As key mediators of signaling cascades, the activation of extracellular signal-regulated kinases 1 and 2 proved to be specific for proliferation in a beta1-integrin-dependent manner, whereas phosphorylation of c-Jun NH2-terminal kinases 1 and 2 was correlated with the induction of apoptosis.
  AJP Lung Cellular and Molecular Physiology 11/2006; 291(4):L725-33. · 3.66 Impact Factor