المؤلفون: Andreas Kulawik, C Ehlting, Ute Albrecht, Wolf D. Lehmann, Johannes G. Bode, Andreas Raue, Raphael Engesser, Matthias Gaestel, Bettina Hahn, Jens Timmer, Dieter Häussinger, Ursula Klingmüller

مصطلحات موضوعية: 0301 basic medicine, MAPK/ERK pathway, Male, MAP Kinase Signaling System, Pyridines, Phosphatase, Interleukin-1beta, Protein Serine-Threonine Kinases, Biochemistry, Models, Biological, p38 Mitogen-Activated Protein Kinases, 03 medical and health sciences, Mice, 0302 clinical medicine, Animals, Kinase activity, Protein kinase A, Molecular Biology, Cells, Cultured, biology, Macrophages, Imidazoles, Intracellular Signaling Peptides and Proteins, Cell Biology, Liver regeneration, Cell biology, 030104 developmental biology, 030220 oncology & carcinogenesis, Mitogen-activated protein kinase, biology.protein, Hepatocytes, Phosphorylation, Signal transduction, Signal Transduction

الوصف: The IL-1β induced activation of the p38MAPK/MAPK-activated protein kinase 2 (MK2) pathway in hepatocytes is important for control of the acute phase response and regulation of liver regeneration. Many aspects of the regulatory relevance of this pathway have been investigated in immune cells in the context of inflammation. However, very little is known about concentration-dependent activation kinetics and signal propagation in hepatocytes and the role of MK2. We established a mathematical model for IL-1β-induced activation of the p38MAPK/MK2 pathway in hepatocytes that was calibrated to quantitative data on time- and IL-1β concentration-dependent phosphorylation of p38MAPK and MK2 in primary mouse hepatocytes. This analysis showed that, in hepatocytes, signal transduction from IL-1β via p38MAPK to MK2 is characterized by strong signal amplification. Quantification of p38MAPK and MK2 revealed that, in hepatocytes, at maximum, 11.3% of p38MAPK molecules and 36.5% of MK2 molecules are activated in response to IL-1β. The mathematical model was experimentally validated by employing phosphatase inhibitors and the p38MAPK inhibitor SB203580. Model simulations predicted an IC50 of 1-1.2 μm for SB203580 in hepatocytes. In silico analyses and experimental validation demonstrated that the kinase activity of p38MAPK determines signal amplitude, whereas phosphatase activity affects both signal amplitude and duration. p38MAPK and MK2 concentrations and responsiveness toward IL-1β were quantitatively compared between hepatocytes and macrophages. In macrophages, the absolute p38MAPK and MK2 concentration was significantly higher. Finally, in line with experimental observations, the mathematical model predicted a significantly higher half-maximal effective concentration for IL-1β-induced pathway activation in macrophages compared with hepatocytes, underscoring the importance of cell type-specific differences in pathway regulation.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1a342369dd6be124e4407bd3bc2360deTest
https://europepmc.org/articles/PMC5391758Test/

المؤلفون: Nao Iwamoto, Maria Muciek, Ursula Klingmüller, Daniela Deharde, Wolf D. Lehmann, Susen Lattermann, Matthias S. Matter, Mathias Heikenwalder, Georg Damm, Markus Stepath, Katrin Hoffmann, Jens Timmer, Martin E. Boehm, Clemens Kreutz, Bernhard Steiert, Marvin Wäsch, Marcel Schilling, Philippe Lucarelli, Daniel Seehofer, Norbert Gretz, Artyom Vlasov

المصدر: Cell Systems. United States (2017).

مصطلحات موضوعية: Male, 0301 basic medicine, Transcription, Genetic, Transcription factor complex, Smad Proteins, SMAD, Biochemistry, biophysics & molecular biology [F05] [Life sciences], Mass Spectrometry, Mice, Transforming Growth Factor beta, Gene expression, TGF-beta signal transduction, Phosphorylation, Biochimie, biophysique & biologie moléculaire [F05] [Sciences du vivant], Regulation of gene expression, Smad proteins and complexes, Chemistry, Liver Neoplasms, mathematical modeling, systems biology, Hep G2 Cells, hepatocellular carcinoma, Middle Aged, SMAD protein complex, dynamic pathway modeling, Cell biology, DNA-Binding Proteins, Liver, Female, regulation of gene expression, Signal Transduction, L1 regularization, Carcinoma, Hepatocellular, Histology, Systems biology, quantitative mass spectrometry, liver, Pathology and Forensic Medicine, 03 medical and health sciences, Cell Line, Tumor, Animals, Humans, Gene, Aged, Cell Biology, Mice, Inbred C57BL, 030104 developmental biology, Hepatocytes, Trans-Activators, Transforming growth factor

الوصف: Upon stimulation of cells with transforming growth factor beta (TGF-beta), Smad proteins form trimeric complexes and activate a broad spectrum of target genes. It remains unresolved which of the possible Smad complexes are formed in cellular contexts and how these contribute to gene expression. By combining quantitative mass spectrometry with a computational selection strategy, we predict and provide experimental evidence for the three most relevant Smad complexes in the mouse hepatoma cell line Hepa1-6. Utilizing dynamic pathway modeling, we specify the contribution of each Smad complex to the expression of representative Smad target genes, and show that these contributions are conserved in human hepatoma cell lines and primary hepatocytes. We predict, based on gene expression data of patient samples, increased amounts of Smad2/3/4 proteins and Smad2 phosphorylation as hallmarks of hepatocellular carcinoma and experimentally verify this prediction. Our findings demonstrate that modeling approaches can disentangle the complexity of transcription factor complex formation and its impact on gene expression.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ac6954a23a6d6994b6d66b53397fae48Test
https://doi.org/10.1016/j.cels.2017.11.010Test

المؤلفون: Gerhard Erben, Wolf D. Lehmann, Dietrich Keppler, Martin Koester

المصدر: Analytical Biochemistry. 246:102-110

مصطلحات موضوعية: Male, Electrospray, Chromatography, Chemistry, Biophysics, Spectrometry, Mass, Secondary Ion, Cell Biology, Tandem mass spectrometry, Biochemistry, Rats, Triple quadrupole mass spectrometer, Excretion, chemistry.chemical_compound, medicine.anatomical_structure, Hepatocyte, Cyclosporin a, Phosphatidylcholine, Cyclosporine, Phosphatidylcholines, medicine, Mass spectrum, Animals, Bile, Rats, Wistar, Molecular Biology

الوصف: Rat bile phosphatidylcholine was structurally characterized and quantified by electrospray mass spectrometry using a triple quadrupole instrument. All results were obtained by direct analysis of an unprocessed total lipid extract from rat bile. Structural characterization of phosphatidylcholine was achieved by collision-induced dissociation of [M + Cl] − ions observed in the negative-ion electrospray mass spectrum. Quantification of phosphatidylcholine was performed in the positive-ion mode using precursor ion scanning of m / z 184 and dimyristoyl-phosphatidylcholine as internal standard. Using this new methodology, the effect of cyclosporin A on biliary phosphatidylcholine excretion in the rat was investigated. After intravenous administration of cyclosporin A (25 mg/kg body wt) the phosphatidylcholine level in bile was reduced to about 30% of the control level. This suggests an inhibition by cyclosporin A of the translocation of phosphatidylcholine across the hepatocyte canalicular membrane which is mediated by the Mdr2 P-glycoprotein.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::bb0c114abf78d54b946571a236b852f2Test
https://doi.org/10.1006/abio.1996.9941Test

المؤلفون: Ertan Mayatepek, Hélène Bellet, Wolf D. Lehmann, Stéphanie Badiou

المصدر: Annals of Neurology. 58:968-970

مصطلحات موضوعية: Male, Dipeptidase, medicine.medical_specialty, Leukotriene D4, Adolescent, Metabolite, Urinary system, Neurological disorder, Deafness, chemistry.chemical_compound, Intellectual Disability, Internal medicine, medicine, Humans, Leukotriene E4, Leukotriene, biology, Neuromuscular Diseases, Metabolism, respiratory system, medicine.disease, Leukotriene C4, Endocrinology, Neurology, chemistry, Eicosanoid, biology.protein, SRS-A, lipids (amino acids, peptides, and proteins), Neurology (clinical)

الوصف: A 15-year-old male patient presented with mental retardation, mild motor impairment, and partial deafness. Biochemical investigations showed an abnormal urinary profile of leukotrienes. Concentration of leukotriene D4 (LTD4), which is usually not detectable, was highly increased, whereas LTE4, the major urinary metabolite in humans, was completely absent. These data suggest membrane-bound dipeptidase deficiency, a new defect in leukotriene biosynthesis on the step of LTE4 synthesis, as underlying defect. Ann Neurol 2005;58:968–970

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b37f9b497b7e3793625dadefb1a2909bTest
https://doi.org/10.1002/ana.20687Test

المؤلفون: Ertan Mayatepek, Wolf D. Lehmann

المصدر: Clinica Chimica Acta. 249:37-46

مصطلحات موضوعية: Adult, Male, medicine.medical_specialty, Urinary system, Clinical Biochemistry, Kidney, Biochemistry, Excretion, chemistry.chemical_compound, Dubin–Johnson syndrome, Internal medicine, Pigment accumulation, medicine, Humans, Chromatography, High Pressure Liquid, Aged, Leukotriene E4, Leukotriene, Creatinine, Jaundice, Chronic Idiopathic, Biochemistry (medical), General Medicine, Middle Aged, medicine.disease, Endocrinology, medicine.anatomical_structure, Liver, chemistry, Female, Bile Ducts

الوصف: The Dubin-Johnson syndrome (DJS) is characterized by a hereditary conjugated hyperbilirubinemia and a typical dark pigment accumulation in liver parenchymal cells. In the present study the renal excretion of leukotrienes in five patients with histologically established DJS and five age- and sex-matched healthy subjects was investigated. Endogenous urinary leukotrienes were separated by high-performance liquid chromatography and subsequently quantified by immunoassays and gas chromatography-mass spectrometry. Patients with DJS excreted significantly (P < 0.01) greater amounts of cysteinyl leukotriene, LTE4 (8-fold), the omega-oxidation product omega-carboxy-LTE4 (15-fold) and the beta-oxidation metabolite omega-carboxy-tetranor-LTE3 (26-fold) into urine than healthy controls. These results imply that in DJS leukotriene elimination into bile is defective, leading to a compensatory renal leukotriene elimination and a typical excretion pattern of urinary leukotriene metabolites. Analysis of endogenous urinary leukotrienes seems to be a new approach to the noninvasive diagnosis of this disease.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::9e2bb5b0ca75d1fa15cd9176d83fa4feTest
https://doi.org/10.1016/0009-8981Test(95)06256-4

المؤلفون: Stefan Hengl, Jens Timmer, Dominic Winter, Clemens Kreutz, Thomas Maiwald, Wolf D. Lehmann, Walter Kolch, Marcel Schilling, Ursula Klingmüller

المصدر: Molecular Systems Biology

مصطلحات موضوعية: Male, MAPK/ERK pathway, Gene isoform, late stent thrombosis, proliferation, cytokine receptor, Cell fate determination, Biology, Transfection, Models, Biological, information processing, Article, endothelialization, General Biochemistry, Genetics and Molecular Biology, Mice, restenosis, sensitivity analysis, Receptors, Erythropoietin, Animals, Phosphorylation, Extracellular Signal-Regulated MAP Kinases, Erythropoietin, Cells, Cultured, Embryonic Stem Cells, Cell Proliferation, Erythroid Precursor Cells, Feedback, Physiological, Mice, Inbred BALB C, General Immunology and Microbiology, Cell growth, Kinase, Applied Mathematics, Reproducibility of Results, Cell biology, Enzyme Activation, Isoenzymes, Kinetics, ERK, Computational Theory and Mathematics, liposome, coronary artery stents, Female, Signal transduction, General Agricultural and Biological Sciences, Signal Transduction, Information Systems

الوصف: Cell fate decisions are regulated by the coordinated activation of signalling pathways such as the extracellular signal-regulated kinase (ERK) cascade, but contributions of individual kinase isoforms are mostly unknown. By combining quantitative data from erythropoietin-induced pathway activation in primary erythroid progenitor (colony-forming unit erythroid stage, CFU-E) cells with mathematical modelling, we predicted and experimentally confirmed a distributive ERK phosphorylation mechanism in CFU-E cells. Model analysis showed bow-tie-shaped signal processing and inherently transient signalling for cytokine-induced ERK signalling. Sensitivity analysis predicted that, through a feedback-mediated process, increasing one ERK isoform reduces activation of the other isoform, which was verified by protein over-expression. We calculated ERK activation for biochemically not addressable but physiologically relevant ligand concentrations showing that double-phosphorylated ERK1 attenuates proliferation beyond a certain activation level, whereas activated ERK2 enhances proliferation with saturation kinetics. Thus, we provide a quantitative link between earlier unobservable signalling dynamics and cell fate decisions. Not Specified Deposited by bulk import

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0f58cfc61529d21bee205fee31009495Test
https://doi.org/10.1038/msb.2009.91Test

المؤلفون: Dora V. Kaloyanova, Andreas Schlosser, Friedrich Lottspeich, Ramon L Serrano, Joachim Füllekrug, J. Bernd Helms, Felix T. Wieland, Wolf D. Lehmann, Heike B. Eberle

المصدر: Journal of cell science. 115(Pt 4)

مصطلحات موضوعية: Male, Immunoprecipitation, Caveolin 1, Molecular Sequence Data, Golgi Apparatus, CHO Cells, Biology, Caveolins, symbols.namesake, Cytosol, Membrane Microdomains, Cricetinae, Caveolin, Animals, Humans, Endomembrane system, Tissue Distribution, Amino Acid Sequence, Golgi localization, Pathogenesis-related protein, Plant Proteins, Protein Synthesis Inhibitors, Brefeldin A, Base Sequence, Sequence Homology, Amino Acid, Endoplasmic reticulum, Lipid microdomain, Membrane Proteins, Cell Biology, Sequence Analysis, DNA, Golgi apparatus, Cell biology, Rats, Molecular Weight, Biochemistry, symbols, Female

الوصف: Group 1 of plant pathogenesis-related proteins (PR-1) and a variety of related mammalian proteins constitute a superfamily of proteins that share structural similarities. Little is known about their function, but all the family members identified to date are co-translationally translocated to the lumen of the endoplasmic reticulum and are secreted as soluble proteins or are targeted to vacuoles. Here we report the identification of a novel family member that localizes to the cytosolic site of the endomembrane system in mammalian cells. After detergent solubilization of isolated Golgi membranes, a 17 kDa protein was found associated with a low-density detergent-insoluble fraction. The amino-acid sequence, determined by microsequencing and molecular cloning, revealed a significant homology with the superfamily of PR-1 proteins. Golgi-associated PR-1 protein (GAPR-1) showed a brefeldin-A-sensitive Golgi localization in immunofluorescence. Interestingly,the protein remained associated with the microdomain fraction in the presence of Brefeldin A. By mass spectrometry, GAPR-1 was shown to be myristoylated. Immunoprecipitation of GAPR- 1 from Golgi membranes resulted in the coimmunoprecipitation of caveolin-1, indicating a direct interaction between these two proteins. Myristoylation, together with protein-protein or electrostatic interactions at physiological pH owing to the highly basic pI of GAPR-1 (pI 9.4) could explain the strong membrane association of GAPR-1. Tissue screening revealed that GAPR-1 is not detectably expressed in liver,heart or adrenal glands. High expression was found in monocytes, leukocytes,lung, spleen and embryonic tissue. Consistent with the involvement of PR-1 proteins in the plant immune system, these data could indicate that GAPR-1 is involved in the immune system.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::4c8130581395986fb7cca15c063739afTest
https://pubmed.ncbi.nlm.nih.gov/11865038Test

المؤلفون: Karin Müller-Decker, Wolf D. Lehmann, A. Kecskes, T. Heinzelmann, F. Marks, G. Furstenberger

المصدر: Toxicology and applied pharmacology. 153(1)

مصطلحات موضوعية: Adult, Male, Erythema, Prostaglandin, Polysorbates, Human skin, Pharmacology, Toxicology, medicine.disease_cause, chemistry.chemical_compound, Surface-Active Agents, medicine, Humans, Skin, Transepidermal water loss, Arachidonic Acid, integumentary system, Sodium Dodecyl Sulfate, Water, Patch Tests, Suction blister, chemistry, Eicosanoid, Biochemistry, Ethanolamines, Dermatitis, Irritant, Eicosanoids, Arachidonic acid, medicine.symptom, Irritation, Benzalkonium Compounds, Interleukin-1

الوصف: A clinical study was performed to determine the effects of patch testing human skin with four industrially used surfactants on erythema formation, transepidermal water loss, and the contents in suction blister fluids of primary proinflammatory mediators including arachidonic acid, eicosanoids, and IL-1α, which were analyzed by quantitative gas chromatography/negative ion chemical ionization mass spectrometry and by an enzyme-immunoassay, respectively. Benzalkonium chloride (BKCl) and sodium lauryl sulfate (SLS) elicited erythema and caused increased transepidermal water loss, indicating a disturbance of the epidermal barrier. Triethanolamine (TEA) and Tween 80 did not evoke these gross symptoms of inflammation. Suction blister fluids collected after a 24-h application of BKCl, SLS, and Tween 80 contained significantly increased amounts of individual eicosanoids whereas TEA induced no response. The induced eicosanoid profile was characteristic for each compound, pointing to different cell types of skin to be involved in their production. The elevation of prostaglandin and LTB 4 contents correlated with the induction of erythema and the impairment of the epidermal barrier as shown for BKCl and SLS and preceded the maximum of erythema formation. IL-1α contents did not correlate with these gross symptoms of inflammation. The results of this in vivo study support those of a previous study using human keratinocytes in culture indicating the release of arachidonic acid and prostaglandins to be an early event involved in the interaction of keratinocytes with surfactants. Moreover, the in vivo data with human skin underscore the mechanistic relationship to the in vitro model and support the concept that arachidonic acid and eicosanoid release from keratinocytes can be used as a marker of primary skin irritation.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b231be48d3118867323f04c660a48b02Test
https://pubmed.ncbi.nlm.nih.gov/9875300Test

المؤلفون: Andreas Sütterle, Michael Eisenhut, Wolf D. Lehmann

المصدر: Nuclear medicine and biology. 20(6)

مصطلحات موضوعية: Male, Cancer Research, Metabolite, Pentadecanoic acid, In Vitro Techniques, Spectrometry, Mass, Fast Atom Bombardment, Mass spectrometry, High-performance liquid chromatography, Models, Biological, Iodine Radioisotopes, Rats, Sprague-Dawley, chemistry.chemical_compound, Animals, Radiology, Nuclear Medicine and imaging, Chromatography, High Pressure Liquid, chemistry.chemical_classification, Chromatography, Chemistry, Iodobenzenes, Myocardium, Fatty acid, Metabolism, Fast atom bombardment, Rats, Perfusion, Propanoic acid, Molecular Medicine

الوصف: The metabolism of 15-(4′-iodophenyl)pentadecanoic acid (IPPA) in the heart muscle is commonly believed to end at 4-iodobenzoic acid as the main and final product of β-oxidation. However, investigation of the metabolic fate of IPPA in Langendorff rat hearts using high pressure liquid chromatography (HPLC) and negative fast atom bombardment mass spectrometry (FAB-MS) revealed new results. After perfusing isolated rat hearts with [123I]IPPA, metabolites were monitored by HPLC using simultaneous detection of γ-radioactivity and u.v. absorbance. The identification of HPLC separated metabolites was based on their nominal molecular weights as determined by negative FAB-MS. According to these measurements five catabolites were identified with decreasing concentration: 3-(4′-iodophenyl)propenoic acid ⪢ 3-(4′-iodophenyl)propanoic acid = 5-(4′-iodophenyl)-3-hydroxypentanoic acid ⪢ 4-iodobenzoic acid. Additionally, an anabolic metabolite was found exclusively in the lipid ester fraction. From the hydrolysed heart lipids this compound was identified as 11-(4′-iodophenyl)undecanoic acid. Its formation is explained by the action of cytosolic fatty acid synthetase on IPPA catabolites. This metabolic behaviour may be of importance for the interpretation of sequential heart scintigraphy performed with [123I]IPPA.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a69dbbae0f3151db8df6886e2e49e40cTest
https://pubmed.ncbi.nlm.nih.gov/8401375Test

المؤلفون: Heilmuth C Heinrich, Wolf D Lehmann

المصدر: The American Journal of Clinical Nutrition. 44:468-474

مصطلحات موضوعية: Adult, Male, medicine.medical_specialty, Phenylalanine hydroxylase, Phenylketonurias, Anemia, Iron, Phenylalanine, Medicine (miscellaneous), Internal medicine, medicine, Humans, Tyrosine, Anemia, Hypochromic, Nutrition and Dietetics, biology, Chemistry, Genetic Carrier Screening, Phenylalanine Hydroxylase, Fasting, Iron deficiency, Middle Aged, medicine.disease, Endocrinology, Iron-deficiency anemia, biology.protein, Female, Hemoglobin

الوصف: Ten patients with manifest iron deficiency and without documented relationship to phenylketonuria patients were orally loaded with 25 mg/kg of L-(2H5)phenylalanine. Before loading, the fasting phenylalanine-tyrosine plasma ratio was determined and after loading, the concentrations of labeled and nonlabeled phenylalanine and tyrosine were determined in five consecutive plasma samples. With respect to the fasting phenylalanine-tyrosine ratio and to the post-load ratios of labeled phenylalanine over labeled tyrosine, the iron-deficient patients showed data intermediate between those of normals and heterozygotes for phenylketonuria. Compared to a 100% in vivo activity of phenylalanine hydroxylase in normals and a circa 37% activity in heterozygotes for classic phenylketonuria, iron-deficient patients with an average hemoglobin of 8.6 +/- 1 g/dl showed an activity of circa 56%. After normalization of their iron status, four patients were subjected again to the L-(2H5)phenylalanine-loading test. For three of these individuals, test results shifted into the range of normal.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ccda1bf57a8d5249b650d209ad08859aTest
https://doi.org/10.1093/ajcn/44.4.468Test