105 results on '"G. Birkenmeier"'
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2. First measurements of an imaging heavy ion beam probe at the ASDEX Upgrade tokamak.
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Galdon-Quiroga J, Birkenmeier G, Oyola P, Lindl H, Rodriguez-Gonzalez A, Anda G, Garcia-Munoz M, Herrmann A, Kalis J, Kaunert K, Lunt T, Refy D, Rohde V, Rueda-Rueda J, Sochor M, Tal B, Teschke M, Videla M, Viezzer E, and Zoletnik S
- Abstract
The imaging heavy ion beam probe (i-HIBP) diagnostic has been successfully commissioned at ASDEX Upgrade. The i-HIBP injects a primary neutral beam into the plasma, where it is ionized, leading to a fan of secondary (charged) beams. These are deflected by the magnetic field of the tokamak and collected by a scintillator detector, generating a strike-line light pattern that encodes information on the density, electrostatic potential, and magnetic field of the plasma edge. The first measurements have been made, demonstrating the proof-of-principle of this diagnostic technique. A primary beam of 85/87Rb has been used with energies ranging between 60 and 72 keV and extracted currents up to 1.5 mA. The first signals have been obtained in experiments covering a wide range of parameter spaces, with plasma currents (Ip) between 0.2 and 0.8 MA and on-axis toroidal magnetic field (Bt) between 1.9 and 2.7 T. Low densities appear to be critical for the performance of the diagnostic, as signals are typically observed only when the line integrated density is below 2.0-3.0 × 1019 m-2 in the central interferometer chord, depending on the plasma shape. The strike line moves as expected when Ip is ramped, indicating that current measurements are possible. Additionally, clear dynamics in the intensity of the strike line are often observed, which might be linked to changes in the edge profile structure. However, the signal-to-background ratio of the signals is hampered by stray light, and the image guide degradation is due to neutron irradiation. Finally, simulations have been carried out to investigate the sensitivity of the expected signals to plasma density and temperature. The results are in qualitative agreement with the experimental observations, suggesting that the diagnostic is almost insensitive to fluctuations in the temperature profile, while the signal level is highly determined by the density profile due to the beam attenuation., (© 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).)
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- 2024
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3. Implementation of synthetic fast-ion loss detector and imaging heavy ion beam probe diagnostics in the 3D hybrid kinetic-MHD code MEGA.
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Oyola P, Gonzalez-Martin J, Garcia-Munoz M, Galdon-Quiroga J, Birkenmeier G, Viezzer E, Dominguez-Palacios J, Rueda-Rueda J, Rivero-Rodriguez JF, and Todo Y
- Abstract
A synthetic fast-ion loss (FIL) detector and an imaging Heavy Ion Beam Probe (i-HIBP) have been implemented in the 3D hybrid kinetic-magnetohydrodynamic code MEGA. First synthetic measurements from these two diagnostics have been obtained for neutral beam injection-driven Alfvén Eigenmode (AE) simulated with MEGA. The synthetic FILs show a strong correlation with the AE amplitude. This correlation is observed in the phase-space, represented in coordinates (P
ϕ , E), being toroidal canonical momentum and energy, respectively. FILs and the energy exchange diagrams of the confined population are connected with lines of constant E' , a linear combination of E and Pϕ . First i-HIBP synthetic signals also have been computed for the simulated AE, showing displacements in the strike line of the order of ∼1 mm, above the expected resolution in the i-HIBP scintillator of ∼100 μm.- Published
- 2021
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4. In Vitro Cytotoxicity of Zinc Fructoborate, a Novel Zinc-Boron Active Natural Complex.
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Oancea CN, Cîmpean A, Ion R, Neamţu J, Biţă A, Scorei IR, Neamţu AS, Rogoveanu OC, Zaharie SI, and Birkenmeier G
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In recent years, the role of zinc in biological systems has been a subject of intense research. Zinc is required for multiple metabolic processes as a structural, regulatory, or catalytic ion. The objective of this study, was to assess the toxicity profile of a newly synthesized zinc-boron molecule on cultured cells. Zinc fructoborate, at different levels of concentration, was tested for its impact on the Vero kidney cell line (ATCC® CCL-81™) using the MTT assay. The compound exhibited a low cytotoxic effect on the cell line. Thus, our study demonstrates that the zinc fructoborate could become a promising dietary supplement molecule.
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- 2018
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5. Correction: The anti-tumorigenic activity of A2M-A lesson from the naked mole-rat.
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Kurz S, Thieme R, Amberg R, Groth M, Jahnke HG, Pieroh P, Horn LC, Kolb M, Huse K, Platzer M, Volke D, Dehghani F, Buzdin A, Engel K, Robitzki A, Hoffmann R, Gockel I, and Birkenmeier G
- Abstract
[This corrects the article DOI: 10.1371/journal.pone.0189514.].
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- 2018
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6. Comparative Examination of Temporal Glyoxalase 1 Variations Following Perforant Pathway Transection, Excitotoxicity, and Controlled Cortical Impact Injury.
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Pieroh P, Wagner DC, Alessandri B, Dabbagh Nazari M, Ehrlich A, Ghadban C, Hobusch C, Birkenmeier G, and Dehghani F
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- Animals, Astrocytes drug effects, Astrocytes metabolism, Brain drug effects, Brain physiopathology, Hippocampus drug effects, Hippocampus metabolism, Immunohistochemistry methods, Neurons drug effects, Neurons metabolism, Perforant Pathway physiopathology, Rats, Sprague-Dawley, Brain Injuries physiopathology, Lactoylglutathione Lyase metabolism, Perforant Pathway drug effects, Pyruvaldehyde pharmacology
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Following acute neuronal lesions, metabolic imbalance occurs, the rate of glycolysis increases, and methylglyoxal (MGO) forms, finally leading to metabolic dysfunction and inflammation. The glyoxalase system is the main detoxification system for MGO and is impaired following excitotoxicity and stroke. However, it is not known yet whether alterations of the glyoxalase system are also characteristic for other neuronal damage models. Neuronal damage was induced in organotypic hippocampal slice cultures by transection of perforant pathway (PPT; 5 min to 72 h) and N-methyl-D-aspartate (NMDA; 50 μM for 4 h) or in vivo after controlled cortical impact (CCI) injury (2 h to 14 days). Temporal and spatial changes of glyoxalase I (GLO1) were investigated by Western blot analyses and immunohistochemistry. In immunoblot, the GLO1 protein content was not significantly affected by PPT at all investigated time points. As described previously, NMDA treatment led to a GLO1 increase 24 and 48 h after the lesion, whereas PPT increased GLO1 immunoreactivity within neurons only at 48 h postinjury. Immunohistochemistry of brain tissue subjected to CCI unveiled positive GLO1 immunoreactivity in neurons and astrocytes at 1 and 3 days after injury. Two hours and 14 days after CCI, no GLO1 immunoreactivity was observed. GLO1 protein content changes are associated with excitotoxicity but seemingly not to fiber transection. Cell-specific changes in GLO1 immunoreactivity after different in vitro and in vivo lesion types might be a common phenomenon in the aftermath of neuronal lesions.
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- 2018
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7. The anti-tumorigenic activity of A2M-A lesson from the naked mole-rat.
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Kurz S, Thieme R, Amberg R, Groth M, Jahnke HG, Pieroh P, Horn LC, Kolb M, Huse K, Platzer M, Volke D, Dehghani F, Buzdin A, Engel K, Robitzki A, Hoffmann R, Gockel I, and Birkenmeier G
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- Animals, Heterografts, Humans, Models, Animal, Mole Rats, Neoplasms pathology, PTEN Phosphohydrolase metabolism, Phosphatidylinositol 3-Kinases metabolism, Proto-Oncogene Proteins c-akt metabolism, Smad Proteins metabolism, Neoplasms prevention & control, Pregnancy-Associated alpha 2-Macroglobulins physiology
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Cancer resistance is a major cause for longevity of the naked mole-rat. Recent liver transcriptome analysis in this animal compared to wild-derived mice revealed higher expression of alpha2-macroglobulin (A2M) and cell adhesion molecules, which contribute to the naked mole-rat's cancer resistance. Notably, A2M is known to dramatically decrease with age in humans. We hypothesize that this might facilitate tumour development. Here we found that A2M modulates tumour cell adhesion, migration and growth by inhibition of tumour promoting signalling pathways, e.g. PI3K / AKT, SMAD and up-regulated PTEN via down-regulation of miR-21, in vitro and in tumour xenografts. A2M increases the expression of CD29 and CD44 but did not evoke EMT. Transcriptome analysis of A2M-treated tumour cells, xenografts and mouse liver demonstrated a multifaceted regulation of tumour promoting signalling pathways indicating a less tumorigenic environment mediated by A2M. By virtue of these multiple actions the naturally occurring A2M has strong potential as a novel therapeutic agent.
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- 2017
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8. Ethyl pyruvate does not require microglia for mediating neuroprotection after excitotoxic injury.
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Pieroh P, Wagner DC, Ghadban C, Birkenmeier G, and Dehghani F
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- Animals, Astrocytes drug effects, Astrocytes pathology, Astrocytes physiology, Cicatrix drug therapy, Cicatrix pathology, Cicatrix physiopathology, Hippocampus drug effects, Hippocampus pathology, Hippocampus physiopathology, Microglia pathology, Microglia physiology, N-Methylaspartate toxicity, Neurons pathology, Neurons physiology, Rats, Sprague-Dawley, Tissue Culture Techniques, Microglia drug effects, Neurons drug effects, Neuroprotective Agents pharmacology, Pyruvates pharmacology
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Aims: Ethyl pyruvate (EP) mediates protective effects after neuronal injury. Besides a direct conservation of damaged neurons, the modulation of indigenous glial cells has been suggested as one important mechanism for EP-related neuroprotection. However, the specific contribution of glial cells is still unknown., Methods: Organotypic hippocampal slice cultures (OHSC) were excitotoxically lesioned by 50 μmol/L N-methyl-D-aspartate (NMDA, for 4 hours) or left untreated. In an additional OHSC subset, microglia was depleted using the bisphosphonate clodronate (100 μg/mL) before lesion. After removal of NMDA, EP containing culture medium (0.84 μmol/L, 8.4 μmol/L, 42 μmol/L, 84 μmol/L, 168 μmol/L) was added and incubated for 72 hours. OHSC were stained with propidium iodide to visualize degenerating neurons and isolectin IB
4 -FITC to identify microglia. Effects of EP at concentrations of 0.84, 8.4, and 84 μmol/L (0-48 hours) were analyzed in the astrocytic scratch wound assay., Results: EP significantly reduced neurodegeneration following induced excitotoxicity except for 168 μmol/L. For 84 μmol/L, a reduction in the microglia cells was observed. Microglia depletion did not affect neuronal survival after EP treatment. EP decelerated astrocytic wound closure at 48 hours after injury., Conclusion: EP-mediated neuroprotection seems to be mediated by astrocytes and/or neurons., (© 2017 John Wiley & Sons Ltd.)- Published
- 2017
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9. Unraveling the gut microbiome of the long-lived naked mole-rat.
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Debebe T, Biagi E, Soverini M, Holtze S, Hildebrandt TB, Birkemeyer C, Wyohannis D, Lemma A, Brigidi P, Savkovic V, König B, Candela M, and Birkenmeier G
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- Animals, Computational Biology methods, Metagenome, Metagenomics methods, RNA, Ribosomal, 16S, Gastrointestinal Microbiome, Longevity, Mole Rats
- Abstract
The naked mole-rat (Heterocephalus glaber) is a subterranean mouse-sized African mammal that shows astonishingly few age-related degenerative changes and seems to not be affected by cancer. These features make this wild rodent an excellent model to study the biology of healthy aging and longevity. Here we characterize for the first time the intestinal microbial ecosystem of the naked mole-rat in comparison to humans and other mammals, highlighting peculiarities related to the specific living environment, such as the enrichment in bacteria able to utilize soil sulfate as a terminal electron acceptor to sustain an anaerobic oxidative metabolism. Interestingly, some compositional gut microbiota peculiarities were also shared with human gut microbial ecosystems of centenarians and Hadza hunter-gatherers, considered as models of a healthy gut microbiome and of a homeostatic and highly adaptive gut microbiota-host relationship, respectively. In addition, we found an enrichment of short-chain fatty acids and carbohydrate degradation products in naked mole-rat compared to human samples. These data confirm the importance of the gut microbial ecosystem as an adaptive partner for the mammalian biology and health, independently of the host phylogeny.
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- 2017
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10. Field-Line Localized Destabilization of Ballooning Modes in Three-Dimensional Tokamaks.
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Willensdorfer M, Cote TB, Hegna CC, Suttrop W, Zohm H, Dunne M, Strumberger E, Birkenmeier G, Denk SS, Mink F, Vanovac B, and Luhmann LC
- Abstract
Field-line localized ballooning modes have been observed at the edge of high confinement mode plasmas in ASDEX Upgrade with rotating 3D perturbations induced by an externally applied n=2 error field and during a moderate level of edge localized mode mitigation. The observed ballooning modes are localized to the field lines which experience one of the two zero crossings of the radial flux surface displacement during one rotation period. The localization of the ballooning modes agrees very well with the localization of the largest growth rates from infinite-n ideal ballooning stability calculations using a realistic 3D ideal magnetohydrodynamic equilibrium. This analysis predicts a lower stability with respect to the axisymmetric case. The primary mechanism for the local lower stability is the 3D distortion of the local magnetic shear.
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- 2017
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11. Verification and characterization of an alternative low density lipoprotein receptor-related protein 1 splice variant.
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Kolb M, Kurz S, Schäfer A, Huse K, Dietz A, Wichmann G, and Birkenmeier G
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- Amino Acid Sequence, Carcinoma, Squamous Cell pathology, Cell Line, Tumor, Head and Neck Neoplasms pathology, Humans, Low Density Lipoprotein Receptor-Related Protein-1 chemistry, Sequence Homology, Amino Acid, Alternative Splicing, Low Density Lipoprotein Receptor-Related Protein-1 genetics
- Abstract
Background: Low density lipoprotein (LDL) receptor-related protein 1 (LRP1) is a ubiquitously expressed multi-ligand endocytosis receptor implicated in a wide range of signalling, among others in tumour biology. Tumour-associated genomic mutations of the LRP1 gene are described, but nothing is known about cancer-associated expression of LRP1 splice variants Therefore, the focus of this study was on an annotated truncated LRP1 splice variant (BC072015.1; NCBI GenBank), referred to as smLRP1, which was initially identified in prostate and lung carcinoma., Methods: Using PCR and quantitative PCR, the expression of LRP1 and smLRP1 in different human tissues and tumour cell lines was screened and compared on tumour biopsies of head and neck squamous cell carcinoma (HNSCC). Using a recently developed anti-smLRP1 antibody, the expression of the putative LRP1 protein isoform in tumour cell lines in Western blot and immunofluorescence staining was further investigated., Results: The alternative transcript smLRP1 is ubiquitously expressed in 12 human cell lines of different origin and 22 tissues which is similar to LRP1. A shift in expression of smLRP1 relative to LRP1 towards smLRP1 was observed in most tumour cell lines compared to healthy tissue. The expression of LRP1 as well as smLRP1 is decreased in HNSCC cell lines in comparison to healthy mucosa. In vitro results were checked using primary HNSCC. Furthermore, the expression of the protein isoform smLRP1 (32 kDa) was confirmed in human tumour cell lines., Conclusions: Similar to LRP1, the truncated splice variant smLRP1 is ubiquitously expressed in healthy human tissues, but altered in tumours pointing to a potential role of smLRP1 in cancer. Comparative results suggest a shift in expression in favour of smLRP1 in tumour cells that warrant further evaluation. The protein isoform is suggested to be secreted.
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- 2017
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12. Modulation of GLO1 Expression Affects Malignant Properties of Cells.
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Hutschenreuther A, Bigl M, Hemdan NY, Debebe T, Gaunitz F, and Birkenmeier G
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- Breast Neoplasms pathology, Cell Hypoxia physiology, Cell Line, Tumor, Cell Transformation, Neoplastic pathology, Female, Glutathione metabolism, HEK293 Cells, Humans, Lactoylglutathione Lyase biosynthesis, Lactoylglutathione Lyase metabolism, MCF-7 Cells, RNA Interference, RNA, Small Interfering genetics, Cell Movement genetics, Cell Proliferation genetics, Cell Transformation, Neoplastic genetics, Glycolysis genetics, Lactoylglutathione Lyase genetics, Pyruvaldehyde metabolism
- Abstract
The energy metabolism of most tumor cells relies on aerobic glycolysis (Warburg effect) characterized by an increased glycolytic flux that is accompanied by the increased formation of the cytotoxic metabolite methylglyoxal (MGO). Consequently, the rate of detoxification of this reactive glycolytic byproduct needs to be increased in order to prevent deleterious effects to the cells. This is brought about by an increased expression of glyoxalase 1 (GLO1) that is the rate-limiting enzyme of the MGO-detoxifying glyoxalase system. Here, we overexpressed GLO1 in HEK 293 cells and silenced it in MCF-7 cells using shRNA. Tumor-related properties of wild type and transformed cells were compared and key glycolytic enzyme activities assessed. Furthermore, the cells were subjected to hypoxic conditions to analyze the impact on cell proliferation and enzyme activities. Our results demonstrate that knockdown of GLO1 in the cancer cells significantly reduced tumor-associated properties such as migration and proliferation, whereas no functional alterations where found by overexpression of GLO1 in HEK 293 cells. In contrast, hypoxia caused inhibition of cell growth of all cells except of those overexpressing GLO1. Altogether, we conclude that GLO1 on one hand is crucial to maintaining tumor characteristics of malignant cells, and, on the other hand, supports malignant transformation of cells in a hypoxic environment when overexpressed., Competing Interests: The authors declare no conflict of interest.
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- 2016
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13. Ethyl Pyruvate: An Anti-Microbial Agent that Selectively Targets Pathobionts and Biofilms.
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Debebe T, Krüger M, Huse K, Kacza J, Mühlberg K, König B, and Birkenmeier G
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The microbiota has a strong influence on health and disease in humans. A causative shift favoring pathobionts is strongly linked to diseases. Therefore, anti-microbial agents selectively targeting potential pathogens as well as their biofilms are urgently demanded. Here we demonstrate the impact of ethyl pyruvate, so far known as ROS scavenger and anti-inflammatory agent, on planktonic microbes and biofilms. Ethyl pyruvate combats preferably the growth of pathobionts belonging to bacteria and fungi independent of the genera and prevailing drug resistance. Surprisingly, this anti-microbial agent preserves symbionts like Lactobacillus species. Moreover, ethyl pyruvate prevents the formation of biofilms and promotes matured biofilms dissolution. This potentially new anti-microbial and anti-biofilm agent could have a tremendous positive impact on human, veterinary medicine and technical industry as well., Competing Interests: The antimicrobial action of EP is already patented by Gerd Birkenmeier and Klaus Huse (Patent number: PCT/EP2006/003466); however, we declare that this does not alter our adherence to PLOS ONE policies on sharing data and materials.
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- 2016
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14. Ethyl Pyruvate Combats Human Leukemia Cells but Spares Normal Blood Cells.
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Birkenmeier G, Hemdan NY, Kurz S, Bigl M, Pieroh P, Debebe T, Buchold M, Thieme R, Wichmann G, and Dehghani F
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- Adult, Female, Glycogen Synthase Kinase 3 beta antagonists & inhibitors, Glycogen Synthase Kinase 3 beta metabolism, Humans, K562 Cells, Leukemia metabolism, Leukemia pathology, Male, Neoplasm Proteins antagonists & inhibitors, Neoplasm Proteins metabolism, Adenosine Triphosphate metabolism, Free Radical Scavengers pharmacology, G1 Phase Cell Cycle Checkpoints drug effects, Leukemia drug therapy, Pyruvates pharmacology
- Abstract
Ethyl pyruvate, a known ROS scavenger and anti-inflammatory drug was found to combat leukemia cells. Tumor cell killing was achieved by concerted action of necrosis/apoptosis induction, ATP depletion, and inhibition of glycolytic and para-glycolytic enzymes. Ethyl lactate was less harmful to leukemia cells but was found to arrest cell cycle in the G0/G1 phase. Both, ethyl pyruvate and ethyl lactate were identified as new inhibitors of GSK-3β. Despite the strong effect of ethyl pyruvate on leukemia cells, human cognate blood cells were only marginally affected. The data were compiled by immune blotting, flow cytometry, enzyme activity assay and gene array analysis. Our results inform new mechanisms of ethyl pyruvate-induced cell death, offering thereby a new treatment regime with a high therapeutic window for leukemic tumors., Competing Interests: The authors have declared that no competing interests exist.
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- 2016
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15. Analysis of cultivable microbiota and diet intake pattern of the long-lived naked mole-rat.
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Debebe T, Holtze S, Morhart M, Hildebrandt TB, Rodewald S, Huse K, Platzer M, Wyohannes D, Yirga S, Lemma A, Thieme R, König B, and Birkenmeier G
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Background: A variety of microbial communities exist throughout the human and animal body. Genetics, environmental factors and long-term dietary habit contribute to shaping the composition of the gut microbiota. For this reason the study of the gut microbiota of a mammal exhibiting an extraordinary life span is of great importance. The naked mole-rat (Heterocephalus glaber) is a eusocial mammal known for its longevity and cancer resistance., Methods: Here we analyzed its gut microbiota by cultivating the bacteria under aerobic and anaerobic conditions and identifying their species by mass spectrometry., Results: Altogether, 29 species of microbes were identified, predominantly belonging to Firmicutes, and Bacteroidetes. The most frequent species were Bacillus megaterium (45.2 %), followed by Bacteroides thetaiotaomicron (19.4 %), Bacteroides ovatus, Staphylococcus sciuri and Paenibacillus spp., each with a frequency of 16.1 %., Conclusion: Overall, the gut of the naked mole-rat is colonized by diverse, but low numbers of cultivable microbes compared with humans and mice. The primary food plants of the rodents are rich in polyphenols and related compounds, possessing anti-microbial, anti-inflammatory, anti-oxidative as well as anti-cancer activity which may contribute to their exceptionally healthy life.
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- 2016
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16. A compact lithium pellet injector for tokamak pedestal studies in ASDEX Upgrade.
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Arredondo Parra R, Moreno Quicios R, Ploeckl B, Birkenmeier G, Herrmann A, Kocsis G, Laggner FM, Lang PT, Lunt T, Macian-Juan R, Rohde V, Sellmair G, Szepesi T, Wolfrum E, Zeidner W, and Neu R
- Abstract
Experiments have been performed at ASDEX Upgrade, aiming to investigate the impact of lithium in an all-metal-wall tokamak and attempting to enhance the pedestal operational space. For this purpose, a lithium pellet injector has been developed, capable of injecting pellets carrying a particle content ranging from 1.82 × 10(19) atoms (0.21 mg) to 1.64 × 10(20) atoms (1.89 mg). The maximum repetition rate is about 2 Hz. Free flight launch from the torus outboard side without a guiding tube was realized. In such a configuration, angular dispersion and speed scatter are low, and a transfer efficiency exceeding 90% was achieved in the test bed. Pellets are accelerated in a gas gun; hence special care was taken to avoid deleterious effects by the propellant gas pulse. Therefore, the main plasma gas species was applied as propellant gas, leading to speeds ranging from 420 m/s to 700 m/s. In order to minimize the residual amount of gas to be introduced into the plasma vessel, a large expansion volume equipped with a cryopump was added into the flight path. In view of the experiments, an optimal propellant gas pressure of 50 bars was chosen for operation, since at this pressure maximum efficiency and low propellant gas flux coincide. This led to pellet speeds of 585 m/s ± 32 m/s. Lithium injection has been achieved at ASDEX Upgrade, showing deep pellet penetration into the plasma, though pedestal broadening has not been observed yet.
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- 2016
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17. Experimental Validation of a Filament Transport Model in Turbulent Magnetized Plasmas.
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Carralero D, Manz P, Aho-Mantila L, Birkenmeier G, Brix M, Groth M, Müller HW, Stroth U, Vianello N, and Wolfrum E
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In a wide variety of natural and laboratory magnetized plasmas, filaments appear as a result of interchange instability. These convective structures substantially enhance transport in the direction perpendicular to the magnetic field. According to filament models, their propagation may follow different regimes depending on the parallel closure of charge conservation. This is of paramount importance in magnetic fusion plasmas, as high collisionality in the scrape-off layer may trigger a regime transition leading to strongly enhanced perpendicular particle fluxes. This work reports for the first time on an experimental verification of this process, linking enhanced transport with a regime transition as predicted by models. Based on these results, a novel scaling for global perpendicular particle transport in reactor relevant tokamaks such as ASDEX-Upgrade and JET is found, leading to important implications for next generation fusion devices.
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- 2015
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18. Ethyl Pyruvate Emerges as a Safe and Fast Acting Agent against Trypanosoma brucei by Targeting Pyruvate Kinase Activity.
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Worku N, Stich A, Daugschies A, Wenzel I, Kurz R, Thieme R, Kurz S, and Birkenmeier G
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- Cell Proliferation drug effects, Cell Survival drug effects, Culture Media chemistry, Drug Delivery Systems methods, Drug Resistance, Enzyme Assays, Kinetics, Protozoan Proteins metabolism, Pyruvate Kinase metabolism, Trypanosoma brucei brucei enzymology, Trypanosoma brucei brucei growth & development, Protozoan Proteins antagonists & inhibitors, Pyruvate Kinase antagonists & inhibitors, Pyruvates pharmacology, Trypanocidal Agents pharmacology, Trypanosoma brucei brucei drug effects
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Background: Human African Trypanosomiasis (HAT) also called sleeping sickness is an infectious disease in humans caused by an extracellular protozoan parasite. The disease, if left untreated, results in 100% mortality. Currently available drugs are full of severe drawbacks and fail to escape the fast development of trypanosoma resistance. Due to similarities in cell metabolism between cancerous tumors and trypanosoma cells, some of the current registered drugs against HAT have also been tested in cancer chemotherapy. Here we demonstrate for the first time that the simple ester, ethyl pyruvate, comprises such properties., Results: The current study covers the efficacy and corresponding target evaluation of ethyl pyruvate on T. brucei cell lines using a combination of biochemical techniques including cell proliferation assays, enzyme kinetics, phasecontrast microscopic video imaging and ex vivo toxicity tests. We have shown that ethyl pyruvate effectively kills trypanosomes most probably by net ATP depletion through inhibition of pyruvate kinase (Ki = 3.0±0.29 mM). The potential of ethyl pyruvate as a trypanocidal compound is also strengthened by its fast acting property, killing cells within three hours post exposure. This has been demonstrated using video imaging of live cells as well as concentration and time dependency experiments. Most importantly, ethyl pyruvate produces minimal side effects in human red cells and is known to easily cross the blood-brain-barrier. This makes it a promising candidate for effective treatment of the two clinical stages of sleeping sickness. Trypanosome drug-resistance tests indicate irreversible cell death and a low incidence of resistance development under experimental conditions., Conclusion: Our results present ethyl pyruvate as a safe and fast acting trypanocidal compound and show that it inhibits the enzyme pyruvate kinase. Competitive inhibition of this enzyme was found to cause ATP depletion and cell death. Due to its ability to easily cross the blood-brain-barrier, ethyl pyruvate could be considered as new candidate agent to treat the hemolymphatic as well as neurological stages of sleeping sickness.
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- 2015
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19. Analysis of Alpha-2 Macroglobulin from the Long-Lived and Cancer-Resistant Naked Mole-Rat and Human Plasma.
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Thieme R, Kurz S, Kolb M, Debebe T, Holtze S, Morhart M, Huse K, Szafranski K, Platzer M, Hildebrandt TB, and Birkenmeier G
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- Animals, Cell Adhesion Molecules metabolism, Humans, Mole Rats, Phylogeny, Neoplasms blood, alpha-Macroglobulins metabolism
- Abstract
Background: The naked mole-rat (NMR) is a long-lived and cancer resistant species. Identification of potential anti-cancer and age related mechanisms is of great interest and makes this species eminent to investigate anti-cancer strategies and understand aging mechanisms. Since it is known that the NMR expresses higher liver mRNA-levels of alpha 2-macroglobulin than mice, nothing is known about its structure, functionality or expression level in the NMR compared to the human A2M., Results: Here we show a comprehensive analysis of NMR- and human plasma-A2M, showing a different prediction in glycosylation of NMR-A2M, which results in a higher molecular weight compared to human A2M. Additionally, we found a higher concentration of A2M (8.3±0.44 mg/mL vs. and 4.4±0.20 mg/mL) and a lower total plasma protein content (38.7±1.79 mg/mL vs. 61.7±3.20 mg/mL) in NMR compared to human. NMR-A2M can be transformed by methylamine and trypsin resulting in a conformational change similar to human A2M. NMR-A2M is detectable by a polyclonal antibody against human A2M. Determination of tryptic and anti-tryptic activity of NMR and human plasma revealed a higher anti-tryptic activity of the NMR plasma. On the other hand, less proteolytic activity was found in NMR plasma compared to human plasma., Conclusion: We found transformed NMR-A2M binding to its specific receptor LRP1. We could demonstrate lower protein expression of LRP1 in the NMR liver tissue compared to human but higher expression of A2M. This was accompanied by a higher EpCAM protein expression as central adhesion molecule in cancer progression. NMR-plasma was capable to increase the adhesion in human fibroblast in vitro most probably by increasing CD29 protein expression. This is the first report, demonstrating similarities as well as distinct differences between A2M in NMR and human plasma. This might be directly linked to the intriguing phenotype of the NMR and suggests that A2M might probably play an important role in anti-cancer and the anti-aging mechanisms in the NMR.
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- 2015
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20. Method for estimating the propagation direction of a coherent plasma structure using a one-dimensional diagnostic array.
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Kobayashi T, Birkenmeier G, Wolfrum E, Laggner FM, Willensdorfer M, Stroth U, Inagaki S, Itoh SI, and Itoh K
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This article proposes a new method to evaluate basic characteristics of the dynamics of a coherent plasma structure (blob). With this method, one can evaluate the propagation angle of a blob in a two-dimensional plasma cross section as well as the blob velocity, size, and amplitude from one-dimensional data. The method is applied to blob measurements from the Lithium beam emission spectroscopy system in ASDEX-Upgrade. Statistical features of the observed blob velocities, angles of propagation, blob sizes, and amplitudes are discussed. The validity of the method is examined by comparing two values of the propagation angle that are evaluated in an independent manner.
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- 2014
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21. The temporal and spatial dynamics of glyoxalase I following excitoxicity and brain ischaemia.
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Pieroh P, Birkenmeier G, and Dehghani F
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- Animals, Cell Death physiology, Humans, Brain Ischemia enzymology, Lactoylglutathione Lyase metabolism
- Abstract
MG (methylglyoxal) is an inevitable metabolite derived from glycolysis leading to protein modification, mitochondrial dysfunction and cell death. The ubiquitous glyoxalase system detoxifies MG under GSH consumption by mean of Glo1 (glyoxalase I) as the rate-limiting enzyme. Neurons are highly vulnerable to MG, whereas astrocytes seem less susceptible due to their highly expressed glyoxalases. In neurodegenerative diseases, MG and Glo1 were found to be pivotal players in chronic CNS (central nervous system) diseases. Comparable results obtained upon MG treatment and NMDA (N-methyl-D-aspartate) receptor activation provided evidence of a possible link. Additional evidence was presented by alterations in Glo1 expression upon stimulation of excitotoxicity as an event in the aftermath of brain ischaemia. Glo1 expression was remarkably changed following ischaemia, and beneficial effects were found after exogenous application of Tat (transactivator of transcription)-Glo1. In summary, there are strong indications that Glo1 seems to be a suitable target to modulate the consequences of acute neuronal injury.
- Published
- 2014
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22. Temporal dynamics of glyoxalase 1 in secondary neuronal injury.
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Pieroh P, Koch M, Wagner DC, Boltze J, Ehrlich A, Ghadban C, Hobusch C, Birkenmeier G, and Dehghani F
- Subjects
- Animals, Blotting, Western, Brain Injuries physiopathology, Endothelium, Vascular metabolism, Immunohistochemistry, Microscopy, Confocal, Organ Culture Techniques, Pyruvaldehyde metabolism, Rats, Rats, Sprague-Dawley, Time Factors, Astrocytes metabolism, Brain Injuries metabolism, Hippocampus metabolism, Lactoylglutathione Lyase metabolism, Neurons metabolism
- Abstract
Background: Enhanced glycolysis leads to elevated levels of the toxic metabolite methylglyoxal which contributes to loss of protein-function, metabolic imbalance and cell death. Neurons were shown being highly susceptible to methylglyoxal toxicity. Glyoxalase 1 as an ubiquitous enzyme reflects the main detoxifying enzyme of methylglyoxal and underlies changes during aging and neurodegeneration. However, little is known about dynamics of Glyoxalase 1 following neuronal lesions so far., Methods: To determine a possible involvement of Glyoxalase 1 in acute brain injury, we analysed the temporal dynamics of Glyoxalase 1 distribution and expression by immunohistochemistry and Western Blot analysis. Organotypic hippocampal slice cultures were excitotoxically (N-methyl-D-aspartate, 50 µM for 4 hours) lesioned in vitro (5 minutes to 72 hours). Additionally, permanent middle cerebral artery occlusion was performed (75 minutes to 60 days)., Results: We found (i) a predominant localisation of Glyoxalase 1 in endothelial cells in non-lesioned brains (ii) a time-dependent up-regulation and re-distribution of Glyoxalase 1 in neurons and astrocytes and (iii) a strong increase in Glyoxalase 1 dimers after neuronal injury (24 hours to 72 hours) when compared to monomers of the protein., Conclusions: The high dynamics of Glyoxalase 1 expression and distribution following neuronal injury may indicate a novel role of Glyoxalase 1.
- Published
- 2014
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23. Exploring glyoxalase 1 expression in prostate cancer tissues: targeting the enzyme by ethyl pyruvate defangs some malignancy-associated properties.
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Baunacke M, Horn LC, Trettner S, Engel KM, Hemdan NY, Wiechmann V, Stolzenburg JU, Bigl M, and Birkenmeier G
- Subjects
- Cell Proliferation drug effects, Drug Delivery Systems methods, Humans, MCF-7 Cells, Male, Single-Blind Method, Biomarkers, Tumor biosynthesis, Gene Expression Regulation, Enzymologic, Lactoylglutathione Lyase antagonists & inhibitors, Lactoylglutathione Lyase biosynthesis, Prostatic Neoplasms enzymology, Pyruvates administration & dosage
- Abstract
Background: The glyoxalase (GLO)1 is part of a ubiquitous detoxification system in the glycolytic pathway of normal and tumor cells. It protects against cellular damage caused by cytotoxic metabolites., Methods: Aiming at exploring the role of GLO1 in prostate cancer, we evaluated and targeted the expression of GLO1 in prostate cancer tissues and cell lines and analyzed its correlation with grading systems and tumor growth indices., Results: Immunohistochemical studies on 37 prostate cancer specimens revealed a positive correlation between Helpap-grading and the cytoplasmic (P = 0.002)/nuclear (P = 0.006) GLO1 level. A positive correlation between Ki-67 proliferation marker and the cytoplasmic GLO1 (P = 0.006) was evident. Furthermore, the highest GLO1 level was detected in the androgen-sensitive LNCaP compared to the androgen-independent Du-145 and PC-3 prostate cell lines and the breast cancer cell MCF-7, both at protein and mRNA level. Treating cancer cells with ethyl pyruvate was found to defang some malignancy-associated properties of cancer cells including proliferation, invasion and anchorage-independent growth. In vitro results revealed that the potency of ethyl pyruvate is increased when cells are metabolically activated by growth stimulators, for example, by fetal calf serum, dihydrotestosterone, tumor growth factor-β1 and leptin., Conclusions: The positive correlation of GLO1 expression level in prostate cancer tissues with the pathological grade and proliferation rate may assign GLO1 as a risk factor for prostate cancer development and progression. Furthermore, our data indicate that inhibitors of GLO1 might be useful to decelerate the cancer cell growth by a novel therapeutic approach that we may call "induced metabolic catastrophe.", (© 2013 Wiley Periodicals, Inc.)
- Published
- 2014
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24. Glycerophosphoglycerol, Beta-alanine, and pantothenic Acid as metabolic companions of glycolytic activity and cell migration in breast cancer cell lines.
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Hutschenreuther A, Birkenmeier G, Bigl M, Krohn K, and Birkemeyer C
- Abstract
In cancer research, cell lines are used to explore the molecular basis of the disease as a substitute to tissue biopsies. Breast cancer in particular is a very heterogeneous type of cancer, and different subgroups of cell lines have been established according to their genomic profiles and tumor characteristics. We applied GCMS metabolite profiling to five selected breast cancer cell lines and found this heterogeneity reflected on the metabolite level as well. Metabolite profiles of MCF-7 cells belonging to the luminal gene cluster proved to be more different from those of the basal A cell line JIMT-1 and the basal B cell lines MDA-MB-231, MDA-MB-435, and MDA-MB-436 with only slight differences in the intracellular metabolite pattern. Lactate release into the cultivation medium as an indicator of glycolytic activity was correlated to the metabolite profiles and physiological characteristics of each cell line. In conclusion, pantothenic acid, beta-alanine and glycerophosphoglycerol appeared to be related to the glycolytic activity designated through high lactate release. Other physiological parameters coinciding with glycolytic activity were high glyoxalase 1 (Glo1) and lactate dehydrogenase (LDH) enzyme activity as well as cell migration as an additional important characteristic contributing to the aggressiveness of tumor cells. Metabolite profiles of the cell lines are comparatively discussed with respect to known biomarkers of cancer progression.
- Published
- 2013
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25. Evaluation of the In Vitro Efficacy of Artemisia annua, Rumex abyssinicus, and Catha edulis Forsk Extracts in Cancer and Trypanosoma brucei Cells.
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Worku N, Mossie A, Stich A, Daugschies A, Trettner S, Hemdan NY, and Birkenmeier G
- Abstract
The current drugs against sleeping sickness are derived from cancer chemotherapeutic approaches. Herein, we aimed at evaluating the in vitro effect of alcoholic extracts of Artemisia annua (AMR), Rumex abyssinicus (RMA), and Catha edulis Forsk (CEF) on proliferation/viability of 1321N1 astrocytoma, MCF-7 breast cancer, THP-1 leukemia, and LNCaP, Du-145, and PC-3 prostate cancer cells and on Trypanosoma brucei cells. Proliferation of tumor cells was evaluated by WST-1 assay and viability/behaviour of T. brucei by cell counting and light microscopy. CEF was the most efficient growth inhibitor in comparison to AMR and RMA. Nevertheless, in LNCaP and THP-1 cells, all extracts significantly inhibited tumor growth at 3 μg/mL. All extracts inhibited proliferation of T. brucei cells in a concentration-dependent manner. Microscopic analysis revealed that 95% of the T. brucei cells died when exposed to 33 μg/mL CEF for 3 hrs. Similar results were obtained using 33 μg/mL AMR for 6 hrs. In case of RMA, however, higher concentrations were necessary to obtain similar effects on T. brucei. This demonstrates the antitumor efficacy of these extracts as well as their ability to dampen viability and proliferation of T. brucei, suggesting a common mechanism of action on highly proliferative cells, most probably by targeting cell metabolism.
- Published
- 2013
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26. Experimental evidence of turbulent transport regulation by zonal flows.
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Birkenmeier G, Ramisch M, Schmid B, and Stroth U
- Abstract
The regulation of turbulent transport by zonal flows is studied experimentally on a flux surface of the stellarator experiment TJ-K. Data of 128 Langmuir probes at different toroidal and poloidal positions on a single flux surface enable us to measure simultaneously the zonal flow activity and the turbulent transport in great detail. A reduction of turbulent transport by 30% during the zonal flow phase is found. It is shown that the reduction process is initiated by a modification in the cross phase between density and electric field followed by a reduction in the fluctuation levels, which sustain low transport levels on larger time scales than the zonal flow lifetime.
- Published
- 2013
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27. Key molecules in the differentiation and commitment program of T helper 17 (Th17) cells up-to-date.
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Hemdan NY, Birkenmeier G, and Wichmann G
- Subjects
- Animals, Autoimmune Diseases immunology, Autoimmune Diseases metabolism, Humans, Interleukin-17 immunology, Interleukin-17 metabolism, Mice, Neoplasms, Signal Transduction, TOR Serine-Threonine Kinases metabolism, Autoimmunity immunology, Cell Differentiation immunology, Cytokines metabolism, Th17 Cells cytology, Th17 Cells immunology, Th17 Cells metabolism, Transcription Factors metabolism
- Abstract
The mechanisms underlying autoimmunity and cancer remain elusive. However, perpendicular evidence has been evolved in the past decade that T helper (Th)17 cells and their related molecules are implicated in initiation and induction of various disease settings including both diseases. Meanwhile, extensive research on Th17 cells elucidated various molecules including cytokines and transcription factors as well as signaling pathways involved in the differentiation, maturation, survival and ultimate commitment of Th17 cells. In the current review, we revise the mechanistic underpinnings delivered by recent research on these molecules in the Th17 differentiation/commitment concert. We emphasize on those molecules proposed as targets for attaining potential therapies of various autoimmune disorders and cancer, aiming both at dampening the dark-side of Th17 repertoire and simultaneously potentiating its benefits in the roster of the antimicrobial response., (Copyright © 2012 Elsevier B.V. All rights reserved.)
- Published
- 2012
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28. Experimental investigation of the magnetic configuration dependence of turbulent transport.
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Birkenmeier G, Ramisch M, Manz P, Nold B, and Stroth U
- Abstract
The dependence of turbulent transport on magnetic field properties is measured in detail on a plasma in a stellarator configuration. Pronounced poloidal asymmetries of fluctuation amplitudes and turbulent transport are observed. The transport maximum is located in regions where normal curvature of the magnetic field is negative and simultaneously the geodesic curvature has positive values. A major role of the local magnetic shear cannot be confirmed. The results can have important implications for the optimization of stellarators and the power influx into the scrape-off layer.
- Published
- 2011
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29. Amyloid-β protein modulates the perivascular clearance of neuronal apolipoprotein E in mouse models of Alzheimer's disease.
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Rolyan H, Feike AC, Upadhaya AR, Waha A, Van Dooren T, Haass C, Birkenmeier G, Pietrzik CU, Van Leuven F, and Thal DR
- Subjects
- Amyloid beta-Protein Precursor genetics, Animals, Apolipoproteins E genetics, Cell Line, Tumor, Disease Models, Animal, Female, Gene Expression Regulation genetics, Glial Fibrillary Acidic Protein metabolism, Humans, LDL-Receptor Related Protein-Associated Protein metabolism, Low Density Lipoprotein Receptor-Related Protein-1, Mice, Mice, Transgenic, Neuroblastoma pathology, Neuroblastoma physiopathology, Presenilin-1 genetics, Receptors, LDL metabolism, Transfection, Tumor Suppressor Proteins metabolism, Alzheimer Disease pathology, Amyloid beta-Peptides metabolism, Apolipoproteins E metabolism, Brain pathology, Cerebral Ventricles physiopathology, Neurons metabolism
- Abstract
The deposition of amyloid-β protein (Aβ) in the brain is a hallmark of Alzheimer's disease (AD). Apolipoprotein E (apoE) is involved in the clearance of Aβ from brain and the APOE ε4 allele is a major risk factor for sporadic AD. We have recently shown that apoE is drained into the perivascular space (PVS), where it co-localizes with Aβ. To further clarify the role of apoE in perivascular clearance of Aβ, we studied apoE-transgenic mice over-expressing human apoE4 either in astrocytes (GE4) or in neurons (TE4). These animals were crossbred with amyloid precursor protein (APP)-transgenic mice and with APP-presenilin-1 (APP-PS1) double transgenic mice. Using an antibody that specifically detects human apoE (h-apoE), we observed that astroglial expression of h-apoE in GE4 mice leads to its perivascular drainage, whereas neuronal expression in TE4 mice does not, indicating that neuron-derived apoE is usually not the subject of perivascular drainage. However, h-apoE was observed not only in the PVS of APP-GE4 and APP-PS1-GE4 mice, but also in that of APP-TE4 and APP-PS1-TE4 mice. In all these mouse lines, we found co-localization of neuron-derived h-apoE and Aβ in the PVS. Aβ and h-apoE were also found in the cytoplasm of perivascular astrocytes indicating that astrocytes take up the neuron-derived apoE bound to Aβ, presumably prior to its clearance into the PVS. The uptake of apoE-Aβ complexes into glial cells was further investigated in glioblastoma cells. It was mediated by α(2)macroglobulin receptor/low density lipoprotein receptor-related protein (LRP-1) and inhibited by adding receptor-associated protein (RAP). It results in endosomal Aβ accumulation within these cells. These results suggest that neuronal apoE-Aβ complexes, but not neuronal apoE alone, are substrates for LRP-1-mediated astroglial uptake, transcytosis, and subsequent perivascular drainage. Thus, the production of Aβ and its interaction with apoE lead to the pathological perivascular drainage of neuronal apoE and provide insight into the pathological interactions of Aβ with neuronal apoE metabolism.
- Published
- 2011
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30. Observation of anomalous ion heating by broadband drift-wave turbulence.
- Author
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Enge S, Birkenmeier G, Manz P, Ramisch M, and Stroth U
- Abstract
Using laser induced fluorescence and passive spectroscopy on a magnetically confined low-temperature plasma, anomalous ion heating is observed which exceeds collisional heating from the electrons by a factor of up to five. Direct wave heating due to the 2.45 GHz microwave as well as stochastic heating by large-amplitude fluctuations could be ruled out as explanations. Good quantitative agreement is found when comparing the missing power in the ion species with heating power due to the dissipation of drift-wave turbulence. This turbulent energy transfer into the ion channel could have important consequences for the interpretation of transport in fusion plasmas.
- Published
- 2010
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31. Interleukin-17-producing T helper cells in autoimmunity.
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Hemdan NY, Birkenmeier G, Wichmann G, Abu El-Saad AM, Krieger T, Conrad K, and Sack U
- Subjects
- Animals, CD4-Positive T-Lymphocytes immunology, Cytokines metabolism, Inflammation immunology, Inflammation metabolism, Mice, Receptors, Cytokine metabolism, STAT3 Transcription Factor metabolism, Transcriptional Activation, Transforming Growth Factors metabolism, Autoimmune Diseases immunology, Autoimmunity, Interleukin-17 immunology, Signal Transduction, Th17 Cells immunology, Th17 Cells metabolism
- Abstract
With all the incredible progress in scientific research over the past two decades, the trigger of the majority of autoimmune disorders remains largely elusive. Research on the biology of T helper type 17 (T(H)17) cells over the last decade not only clarified previous observations of immune regulations and disease manifestations, but also provided considerable information on the signaling pathways mediating the effects of this lineage and its seemingly dual role in fighting the invading pathogens on one hand, and in frightening the host by inducing chronic inflammation and autoimmunity on the other hand. In this context, recent reports have implicated T(H)17 cells in mediating host defense as well as a growing list of autoimmune diseases in genetically-susceptible individuals. Herein, we summarize the current knowledge on T(H)17 in autoimmunity with emphasis on its differentiation factors and some mechanisms involved in initiating pathological events of autoimmunity., (Copyright 2010 Elsevier B.V. All rights reserved.)
- Published
- 2010
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32. Analysis of relative gene dosage and expression differences of the paralogs RABL2A and RABL2B by Pyrosequencing.
- Author
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Kramer M, Backhaus O, Rosenstiel P, Horn D, Klopocki E, Birkenmeier G, Schreiber S, Platzer M, Hampe J, and Huse K
- Subjects
- Animals, Cells, Cultured, DNA genetics, Humans, Lymphocytes metabolism, Monosomy, Pan troglodytes, Polymerase Chain Reaction, Tissue Distribution, rab GTP-Binding Proteins metabolism, Gene Dosage, Gene Expression, Sequence Analysis, DNA, rab GTP-Binding Proteins genetics
- Abstract
The paralogous genes RABL2A (chr2) and RABL2B (chr22) emerged by duplication of a single gene in the human-chimpanzee ancestor and share a high degree of sequence similarity. In Phelan-McDermid-Syndrome microdeletions of 22q13 often also affecting RABL2B are of clinical importance but their incidence is still unknown. We analyzed a German population (190 individuals) for such aneuploidies and the paralogs' expression in cell lines by RABL2 paralogous sequence quantification. For determination of the genomic and transcriptional ratios of RABL2A and RABL2B a Pyrosequencing protocol was introduced as a high-throughput method. During PCR the 3' end of the biotinylated strand is engineered by a backfolding oligonucleotide to hybridize in the Pyrosequencing reaction to an internal site near the sequence to be analyzed. In human samples no deviations of the euploid genomic state could be detected indicating that 22q13 microdeletions involving RABL2B are rare. However, despite equal gene dosage a preferential expression of RABL2B in human tissues and lymphoblastoid cell lines was detected which is most pronounced in brain and placenta. This renders a complete functional complementation of one paralog by the respective other unlikely and hints to a functional and clinical importance, in particular with respect to the 22q13 chromosomal deletion syndrome. Remarkably and in contrast to human, expression levels of the two paralogs in a chimpanzee cell line are equal. This finding is discussed in view of the relocation of RABL2A from its ancestral telomeric to its pericentromeric location in human.
- Published
- 2010
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33. Posttranslational modification of human glyoxalase 1 indicates redox-dependent regulation.
- Author
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Birkenmeier G, Stegemann C, Hoffmann R, Günther R, Huse K, and Birkemeyer C
- Subjects
- Acetylation, Disulfides metabolism, Erythrocytes enzymology, Humans, Lactoylglutathione Lyase antagonists & inhibitors, Mass Spectrometry, Methionine metabolism, Oxidation-Reduction, Glutathione metabolism, Lactoylglutathione Lyase metabolism, Protein Processing, Post-Translational
- Abstract
Background: Glyoxalase 1 (Glo1) and glyoxalase 2 (Glo2) are ubiquitously expressed cytosolic enzymes that catalyze the conversion of toxic alpha-oxo-aldehydes into the corresponding alpha-hydroxy acids using L-glutathione (GSH) as a cofactor. Human Glo1 exists in various isoforms; however, the nature of its modifications and their distinct functional assignment is mostly unknown., Methodology/principal Findings: We characterized native Glo1 purified from human erythrocytes by mass spectrometry. The enzyme was found to undergo four so far unidentified posttranslational modifications: (i) removal of the N-terminal methionine 1, (ii) N-terminal acetylation at alanine 2, (iii) a vicinal disulfide bridge between cysteine residues 19 and 20, and (iv) a mixed disulfide with glutathione on cysteine 139. Glutathionylation of Glo1 was confirmed by immunological methods. Both, N-acetylation and the oxidation state of Cys(19/20), did not impact enzyme activity. In contrast, glutathionylation strongly inhibited Glo1 activity in vitro. The discussed mechanism for enzyme inhibition by glutathionylation was validated by molecular dynamics simulation., Conclusion/significance: It is shown for the first time that Glo1 activity directly can be regulated by an oxidative posttranslational modification that was found in the native enzyme, i.e., glutathionylation. Inhibition of Glo1 by chemical reaction with its co-factor and the role of its intramolecular disulfides are expected to be important factors within the context of redox-dependent regulation of glucose metabolism in cells.
- Published
- 2010
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34. Alpha2-macroglobulin inhibits the malignant properties of astrocytoma cells by impeding beta-catenin signaling.
- Author
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Lindner I, Hemdan NY, Buchold M, Huse K, Bigl M, Oerlecke I, Ricken A, Gaunitz F, Sack U, Naumann A, Hollborn M, Thal D, Gebhardt R, and Birkenmeier G
- Subjects
- Blotting, Western, Cell Adhesion physiology, Cell Line, Tumor, Cell Movement physiology, Cell Proliferation, Gene Expression, Humans, Immunohistochemistry, Astrocytoma metabolism, LDL-Receptor Related Protein-Associated Protein metabolism, Signal Transduction physiology, alpha-Macroglobulins metabolism, beta Catenin metabolism
- Abstract
Targets that could improve the treatment of brain tumors remain important to define. This study of a transformation-associated isoform of alpha2-macroglobulin (A2M*) and its interaction with the low-density lipoprotein receptor-related protein-1 (LRP1) suggests a new mechanism for abrogating the malignant potential of astrocytoma cells. LRP1 bound A2M* found to be associated with an inhibition of tumor cell proliferation, migration, invasion, spheroid formation, and anchorage-independent growth. Transcriptional studies implicated effects on the Wnt/beta-catenin signaling pathway. Notably, LRP1 antibodies could phenocopy the effects of A2M*. Our findings suggest a pathway of tumor suppression in astrocytoma that might be tractable to therapeutic exploitation.
- Published
- 2010
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- View/download PDF
35. [Mechanism of action of orally-applied proteolytic enzymes: mechanistic and therapeutic aspects].
- Author
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Birkenmeier G
- Subjects
- Administration, Oral, Alzheimer Disease pathology, Amyloid beta-Peptides metabolism, Antigen Presentation physiology, Blood Coagulation physiology, Complement Activation physiology, Cytokines metabolism, Fibrinolysis physiology, Humans, Immunity drug effects, Intercellular Signaling Peptides and Proteins metabolism, Neoplasms etiology, Neoplasms pathology, Peptide Hydrolases administration & dosage, Protease Inhibitors pharmacology, Transforming Growth Factor beta1 antagonists & inhibitors, alpha-Macroglobulins pharmacology, Alzheimer Disease prevention & control, Immunity physiology, Neoplasms drug therapy, Peptide Hydrolases pharmacology, Peptide Hydrolases therapeutic use, alpha-Macroglobulins physiology
- Published
- 2008
- Full Text
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36. High-resolution mapping of the 8p23.1 beta-defensin cluster reveals strictly concordant copy number variation of all genes.
- Author
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Groth M, Szafranski K, Taudien S, Huse K, Mueller O, Rosenstiel P, Nygren AO, Schreiber S, Birkenmeier G, and Platzer M
- Subjects
- Genome, Human, Humans, Nucleic Acid Amplification Techniques methods, Phenotype, Chromosome Mapping methods, Chromosomes, Human, Pair 8 genetics, Gene Dosage, Genetic Variation, beta-Defensins genetics
- Abstract
One unexpected feature of the human genome is the high structural variability across individuals. Frequently, large regions of the genome show structural polymorphisms and many vary in their abundance. However, accurate methods for the characterization and typing of such copy number variations (CNV) are needed. The defensin cluster at the human region 8p23.1 is one of the best studied CNV regions due to its potential clinical relevance for innate immunity, inflammation, and cancer. The region can be divided into two subclusters, which harbor predominantly either alpha- or beta-defensin genes. Previous studies assessing individual copy numbers gave different results regarding whether the complete beta-defensin cluster varies or only particular genes therein. We applied multiplex ligation-dependent probe amplification (MLPA) to measure defensin locus copy numbers in 42 samples. The data show strict copy number concordance of all 10 loci typed within the beta-defensin cluster in each individual, while seven loci within the alpha-defensin cluster are consistently found as single copies per chromosome. The exception is DEFA3, which is located within the alpha-defensin cluster and was found to also differ in copy number interindividually. Absolute copy numbers ranged from two to nine for the beta-defensin cluster and zero to four for DEFA3. The CNV-typed individuals, including HapMap samples, are publicly available and may serve as a universal reference for absolute copy number determination. On this basis, MLPA represents a reliable technique for medium- to high-throughput typing of 8p23.1 defensin CNV in association studies for diverse clinical phenotypes.
- Published
- 2008
- Full Text
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37. Ethyl pyruvate and ethyl lactate down-regulate the production of pro-inflammatory cytokines and modulate expression of immune receptors.
- Author
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Hollenbach M, Hintersdorf A, Huse K, Sack U, Bigl M, Groth M, Santel T, Buchold M, Lindner I, Otto A, Sicker D, Schellenberger W, Almendinger J, Pustowoit B, Birkemeyer C, Platzer M, Oerlecke I, Hemdan N, and Birkenmeier G
- Subjects
- Animals, Cytokines biosynthesis, Down-Regulation, Enzyme-Linked Immunosorbent Assay, Flow Cytometry, Humans, Macrophages drug effects, Macrophages enzymology, Mice, Monocytes drug effects, Monocytes enzymology, Pyruvaldehyde pharmacology, Reverse Transcriptase Polymerase Chain Reaction, Anti-Inflammatory Agents, Non-Steroidal pharmacology, Cytokines antagonists & inhibitors, Lactates pharmacology, Lactoylglutathione Lyase antagonists & inhibitors, Pyruvates pharmacology, Receptors, Immunologic metabolism
- Abstract
Esters of alpha-oxo-carbonic acids such as ethyl pyruvate (EP) have been demonstrated to exert inhibitory effects on the production of anti-inflammatory cytokines. So far, there is no information about effects, if any, of ethyl lactate (EL), an obviously inactive analogue of EP, on inflammatory immune responses. In the present study, we provide evidence that the anti-inflammatory action of alpha-oxo-carbonic acid esters is mediated by inhibition of glyoxalases (Glo), cytosolic enzymes that catalyse the conversion of alpha-oxo-aldehydes such as methylglyoxal (MGO) into the corresponding alpha-hydroxy acids using glutathione as a cofactor. In vitro enzyme activity measurements revealed the inhibition of human Glo1 by alpha-oxo-carbonic acid esters, whilst alpha-hydroxy-carbonic acid esters such as EL were not inhibitory. In contrast, both EP and EL were shown to suppress the Lipopolysaccharide (LPS)-induced production of pro-inflammatory cytokines such as tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6 and IL-8 from human immunocompetent cells, and modulated the expression of the immune receptors HLA-DR, CD14 and CD91 on human monocytes. Here, we show a crossing link between glyoxalases and the immune system. The results described herein introduce glyoxalases as a possible target for therapeutic approaches of immune suppression.
- Published
- 2008
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38. Cerebral small vessel disease-induced apolipoprotein E leakage is associated with Alzheimer disease and the accumulation of amyloid beta-protein in perivascular astrocytes.
- Author
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Utter S, Tamboli IY, Walter J, Upadhaya AR, Birkenmeier G, Pietrzik CU, Ghebremedhin E, and Thal DR
- Subjects
- Aged, Aged, 80 and over, Alzheimer Disease complications, Astrocytes metabolism, Blood Vessels metabolism, Blood-Brain Barrier pathology, Blotting, Western, Brain blood supply, Brain pathology, Cerebral Amyloid Angiopathy complications, Cerebral Amyloid Angiopathy pathology, Female, Humans, Immunoglobulin G metabolism, Immunohistochemistry, Low Density Lipoprotein Receptor-Related Protein-1 metabolism, Male, Middle Aged, Alzheimer Disease pathology, Amyloid beta-Peptides metabolism, Apolipoproteins E metabolism, Astrocytes pathology, Blood Vessels pathology
- Abstract
Apolipoprotein E (apoE) plays a role in the pathogenesis of Alzheimer disease (AD). It is involved in the receptor-mediated cellular clearance of the amyloid beta-protein (Abeta) and in the perivascular drainage of the extracellular fluid. Microvascular changes are also associated with AD and have been discussed as a possible reason for altered perivascular drainage. To further clarify the role of apoE in the perivascular and vascular pathology in AD patients, we studied its occurrence and distribution in the perivascular space, the perivascular neuropil, and in the vessel wall of AD and control cases with and without small vessel disease (SVD). Apolipoprotein E was found in the perivascular space and in the neuropil around arteries of the basal ganglia from control and AD cases disclosing no major differences. Western blot analysis of basal ganglia tissue also revealed no significant differences pertaining to the amount of full-length and C-terminal truncated apoE in AD cases compared with controls. In contrast, Abeta occurred in apoE-positive perivascular astrocytes in AD cases but not in controls. In blood vessels, apoE and immunoglobulin G were detected within the SVD-altered vessel wall. The severity of SVD was associated with the occurrence of apoE in the vessel wall and with that of Abeta in perivascular astrocytes. These results point to an important role of apoE in the perivascular clearance of Abeta in the human brain. The occurrence of apoE and immunoglobulin G in SVD lesions and in the perivascular space suggests that the presence of SVD results in plasma-protein leakage into the brain. It is therefore tempting to speculate that apoE represents a pathogenetic link between SVD and AD.
- Published
- 2008
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39. Gingival crevicular fluid levels of aspartate aminotransferase and alpha2-macroglobulin before and after topical application of metronidazole or scaling and root planing.
- Author
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Knöfler G, Purschwitz R, Jentsch H, Birkenmeier G, and Schmidt H
- Subjects
- Adult, Aspartate Aminotransferases analysis, Chronic Periodontitis metabolism, Female, Humans, Male, Periodontal Index, Statistics, Nonparametric, alpha-Macroglobulins analysis, Anti-Infective Agents, Local adverse effects, Aspartate Aminotransferases metabolism, Chronic Periodontitis therapy, Dental Scaling, Gingival Crevicular Fluid chemistry, Metronidazole administration & dosage, alpha-Macroglobulins metabolism
- Abstract
Objective: The aim of this study was to compare the influence of topical metronidazole gel application and scaling and root planing on gingival crevicular fluid variables., Method and Materials: In a split-mouth study, 39 volunteers with chronic periodontitis were treated by metronidazole gel or scaling and root planing. Clinical attachment level and probing depth were recorded, and aspartate aminotransferase (AST) and total/transformed Alpha2-macroglobulin were determined in the gingival crevicular fluid at baseline, as well as after 3 and 6 months., Results: Both treatment procedures resulted in a gain of clinical attachment-0.67 mm for metronidazole and 0.50 mm for scaling and root planing (P< .001)-at the end of the study. The median probing depth was significantly reduced by 0.66 mm for metronidazole and 1.00 mm for scaling and root planing (P< .001) after 6 months. No change of AST was found. Alpha2-macroglobulin was significantly reduced for scaling and root planing and metronidazole after 3 and 6 months (P< .001). No significant difference was found between the 2 procedures at any variable., Conclusions: These data suggest that Alpha2-macroglobulin reflects clinical changes better than AST and that metronidazole and scaling and root planing have the same influence on clinical outcome and biochemical variables in the gingival crevicular fluid.
- Published
- 2008
40. Genetic variants of the copy number polymorphic beta-defensin locus are associated with sporadic prostate cancer.
- Author
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Huse K, Taudien S, Groth M, Rosenstiel P, Szafranski K, Hiller M, Hampe J, Junker K, Schubert J, Schreiber S, Birkenmeier G, Krawczak M, and Platzer M
- Subjects
- Adult, Aged, Biomarkers, Tumor genetics, Case-Control Studies, Cell Line, Tumor, Genetic Linkage genetics, Haplotypes genetics, Humans, Male, Middle Aged, Multigene Family genetics, Prostatic Neoplasms pathology, Chromosomes, Human, Pair 8 genetics, Gene Dosage genetics, Genetic Variation, Polymorphism, Single Nucleotide genetics, Prostatic Neoplasms genetics, beta-Defensins genetics
- Abstract
Background/aims: Prostate cancer represents the cancer with the highest worldwide prevalence in men. Chromosome 8p23 has shown suggestive genetic linkage to early-onset familial prostate cancer and is frequently deleted in cancer cells of the urogenital tract. Within this locus some beta-defensin genes (among them DEFB4, DEFB103, DEFB104) are localized, which are arranged in a gene cluster shown to exhibit an extensive copy number variation in the population. This structural variation considerably hampers genetic studies. In a new approach considering both sequence as well as copy number variations we aimed to compare the defensin locus at 8p23 in prostate cancer patients and controls., Methods: We apply PCR/cloning-based haplotyping and high-throughput copy number determination methods which allow assessment of both individual haplotypes and gene copy numbers not accessible to conventional SNP-based genotyping., Results: We demonstrate association of four common DEFB104 haplotypes with the risk of prostate cancer in two independent patient cohorts. Moreover, we show that high copy numbers (>9) of the defensin gene cluster are significantly underrepresented in both patient samples., Conclusions: Our findings imply a role of the antibacterial defensins in prostate cancerogenesis qualifying distinct gene variants and copy numbers as potential tumor markers., ((c) 2008 S. Karger AG, Basel)
- Published
- 2008
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41. Curcumin inhibits glyoxalase 1: a possible link to its anti-inflammatory and anti-tumor activity.
- Author
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Santel T, Pflug G, Hemdan NY, Schäfer A, Hollenbach M, Buchold M, Hintersdorf A, Lindner I, Otto A, Bigl M, Oerlecke I, Hutschenreuther A, Sack U, Huse K, Groth M, Birkemeyer C, Schellenberger W, Gebhardt R, Platzer M, Weiss T, Vijayalakshmi MA, Krüger M, and Birkenmeier G
- Subjects
- Blood Cells drug effects, Blood Cells metabolism, Cell Proliferation drug effects, Cell Survival drug effects, Cells, Cultured, Drug Evaluation, Preclinical, Enzyme Inhibitors pharmacology, Flavonoids pharmacology, Humans, Interleukin-1beta metabolism, L-Lactate Dehydrogenase metabolism, Lipopolysaccharides pharmacology, Models, Biological, Neoplasms pathology, Phenols pharmacology, Polyphenols, Substrate Specificity, Anti-Inflammatory Agents pharmacology, Antineoplastic Agents, Phytogenic pharmacology, Curcumin pharmacology, Lactoylglutathione Lyase antagonists & inhibitors
- Abstract
Background: Glyoxalases (Glo1 and Glo2) are involved in the glycolytic pathway by detoxifying the reactive methylglyoxal (MGO) into D-lactate in a two-step reaction using glutathione (GSH) as cofactor. Inhibitors of glyoxalases are considered as anti-inflammatory and anti-carcinogenic agents. The recent finding that various polyphenols modulate Glo1 activity has prompted us to assess curcumin's potency as an Glo1 inhibitor., Methodology/principal Findings: Cultures of whole blood cells and tumor cell lines (PC-3, JIM-1, MDA-MD 231 and 1321N1) were set up to investigate the effect of selected polyphenols, including curcumin, on the LPS-induced cytokine production (cytometric bead-based array), cell proliferation (WST-1 assay), cytosolic Glo1 and Glo2 enzymatic activity, apoptosis/necrosis (annexin V-FITC/propidium iodide staining; flow cytometric analysis) as well as GSH and ATP content. Results of enzyme kinetics revealed that curcumin, compared to the polyphenols quercetin, myricetin, kaempferol, luteolin and rutin, elicited a stronger competitive inhibitory effect on Glo1 (K(i) = 5.1+/-1.4 microM). Applying a whole blood assay, IC(50) values of pro-inflammatory cytokine release (TNF-alpha, IL-6, IL-8, IL-1beta) were found to be positively correlated with the K(i)-values of the aforementioned polyphenols. Moreover, whereas curcumin was found to hamper the growth of breast cancer (JIMT-1, MDA-MB-231), prostate cancer PC-3 and brain astrocytoma 1321N1 cells, no effect on growth or vitality of human primary hepatocytes was elucidated. Curcumin decreased D-lactate release by tumor cells, another clue for inhibition of intracellular Glo1., Conclusions/significance: The results described herein provide new insights into curcumin's biological activities as they indicate that inhibition of Glo1 by curcumin may result in non-tolerable levels of MGO and GSH, which, in turn, modulate various metabolic cellular pathways including depletion of cellular ATP and GSH content. This may account for curcumin's potency as an anti-inflammatory and anti-tumor agent. The findings support the use of curcumin as a potential therapeutic agent.
- Published
- 2008
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42. Association of the glutathione S-transferase omega-1 Ala140Asp polymorphism with cerebrovascular atherosclerosis and plaque-associated interleukin-1 alpha expression.
- Author
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Kölsch H, Larionov S, Dedeck O, Orantes M, Birkenmeier G, Griffin WS, and Thal DR
- Subjects
- Aged, Aged, 80 and over, Circle of Willis metabolism, Circle of Willis pathology, Genotype, Glutathione Transferase metabolism, Humans, Interleukin-1alpha metabolism, Interleukin-1beta genetics, Interleukin-1beta metabolism, Middle Aged, Severity of Illness Index, Glutathione Transferase genetics, Interleukin-1alpha genetics, Intracranial Arteriosclerosis genetics, Intracranial Arteriosclerosis pathology, Polymorphism, Genetic
- Abstract
Background and Purpose: Glutathione S-transferase omega-1 is a multifunctional enzyme. The Asp/Asp genotype of the Ala140Asp polymorphism of the GSTO1 gene has been alleged to increase the risk of vascular dementia. The objective of this study is to address the question of whether common vessel disorders known to cause vascular dementia are modified in their severity by this polymorphism., Methods: The severity and expansion of atherosclerosis in the circle of Willis vessels, cerebral small vessel disease, and cerebral amyloid angiopathy were studied in a sample of 79 autopsy cases. Genotyping of the GSTO1 Ala140Asp polymorphism as well as immunohistochemistry for glutathione S-transferase omega-1 was performed., Results: Carriers of the GSTO1 Asp/Asp genotype presented with more severe and widespread atherosclerosis than noncarriers. However, there was no effect on small vessel disease expansion and cerebral amyloid angiopathy severity. Immunohistochemically, we detected interleukin-1 alpha expressing macrophages in the lipid core of atherosclerosis plaques exhibiting glutathione S-transferase omega-1-positive material. GSTO1 Asp/Asp carriers showed larger areas of atherosclerosis plaques containing interleukin-1 alpha-positive material than carriers of the GSTO1 Ala-allele., Conclusions: The GSTO1 Asp/Asp genotype presumably modulates the severity and expansion of atherosclerosis in the circle of Willis. The cellular colocalization of glutathione S-transferase omega-1 and interleukin-1 alpha suggests a functional interaction between both proteins which in part might explain the function of glutathione S-transferase omega-1 in the pathogenesis of cerebral atherosclerosis.
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- 2007
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43. Expression of alpha2-macroglobulin, neutrophil elastase, and interleukin-1alpha differs in early-stage and late-stage atherosclerotic lesions in the arteries of the circle of Willis.
- Author
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Larionov S, Dedeck O, Birkenmeier G, and Thal DR
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- Aged, Aged, 80 and over, Arteriosclerosis classification, Arteriosclerosis pathology, Female, Humans, Male, Middle Aged, Postmortem Changes, Time Factors, Arteriosclerosis metabolism, Circle of Willis metabolism, Interleukin-1alpha metabolism, Leukocyte Elastase metabolism, alpha-Macroglobulins metabolism
- Abstract
Different types of atherosclerotic (AS) lesions can be distinguished histologically and represent different stages of AS plaque development. Late-stage lesions more frequently develop complications such as plaque rupture and thrombosis with vessel occlusion than early AS lesions. To clarify whether protective, destructive, and inflammatory proteins are differentially expressed in early-stage and late-stage AS plaques we examined the proteinase inhibitor alpha(2)-macroglobulin (A2M), the neutrophil elastase (NE)-an enzyme degrading elastin and collagen fibers-and the proinflammatory protein interleukin-1alpha (IL-1alpha) in all types of AS plaques in the arteries of the circle of Willis from 78 human autopsy cases of both genders (61-91 years of age). Paraffin sections of AS plaques were immunostained with antibodies directed against A2M, NE and IL-1alpha. In initial AS lesions A2M was found, whereas NE and IL-1alpha were absent. NE and IL-1alpha became detectable as soon as a significant number of macrophages occurred within AS lesions. With increasing histopathological type of AS lesions, a marked increase of the area of the plaque exhibiting NE and IL-1alpha was observed. The area which exhibits A2M in AS plaques, on the other hand, did not vary significantly between the different stages. Thus, our results indicate a disproportionately high increase of the destructive enzyme NE and the proinflammatory protein IL-1alpha in relation to A2M with the progression of the grade of AS lesions pointing to the transgression of the protective capacity of A2M by NE and IL-1alpha in late-stage plaques. Therefore, our findings support the hypothesis that NE-induced tissue damage in late-stage AS plaques contributes to the development of plaque rupture and subsequent thrombosis.
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- 2007
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44. Binding properties of the cerebral alpha4beta2 nicotinic acetylcholine receptor ligand 2-[18F]fluoro-A-85380 to plasma proteins.
- Author
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Sorger D, Becker GA, Hauber K, Schildan A, Patt M, Birkenmeier G, Otto A, Meyer P, Kluge M, Schliebs R, and Sabri O
- Subjects
- Brain diagnostic imaging, Female, Humans, Male, Middle Aged, Nervous System Diseases diagnostic imaging, Positron-Emission Tomography methods, Protein Binding, Radiopharmaceuticals pharmacokinetics, Azetidines pharmacokinetics, Blood Proteins metabolism, Brain metabolism, Nervous System Diseases blood, Pyridines pharmacokinetics, Receptors, Nicotinic metabolism
- Abstract
Introduction: To determine the availability of nicotinic acetylcholine receptors in different human brain regions using the positron emission tomography (PET) radioligand 2-[18F]fluoro-A-85380 (2-[18F]FA) and invasive approaches for quantification, it is important to correct the arterial input function as well for plasma protein binding (PPB) of the radioligand as for radiolabeled metabolites accumulating in blood. This study deals with some aspects of PPB of 2-[18F]FA., Methods: Patients with different neurological disorders (n=72), such as Parkinson's disease, Alzheimer's disease and multiple sclerosis, and a group of healthy volunteers (n=15) subjected for PET imaging were analyzed for their PPB level of 2-[18F]FA using ultrafiltration. Protein gel electrophoresis of plasma samples was performed to identify the binding protein of 2-[18F]FA. The dependency of PPB on time and on free ligand concentration was analyzed to obtain the binding parameters Bmax and Kd., Results: Albumin was identified to be the binding protein of 2-[18F]FA. PPB of 2-[18F]FA was low at 17+/-4% and did not show significant differences between the groups of patients. Corresponding to this, a narrow range of plasma albumin of 0.62+/-0.05 mM was observed. Bmax was determined as twice the albumin concentration, which indicates two binding sites for 2-[18F]FA on the protein. No time dependence of the PPB could be observed. By relating PPB to Bmax, an average Kd value of 6.0+/-1.5 mM was obtained., Conclusion: This study shows the dependency of PPB of 2-[18F]FA on human albumin plasma concentration. An equation utilizing Bmax and Kd to easily estimate PPB is presented.
- Published
- 2006
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45. Method for preparing single-stranded DNA templates for Pyrosequencing using vector ligation and universal biotinylated primers.
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Groth M, Huse K, Reichwald K, Taudien S, Hampe J, Rosenstiel P, Birkenmeier G, Schreiber S, and Platzer M
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- Biotinylation, Gene Frequency genetics, Genotype, Humans, Nod2 Signaling Adaptor Protein genetics, Polymerase Chain Reaction methods, Polymorphism, Single Nucleotide genetics, Templates, Genetic, DNA Primers genetics, DNA, Single-Stranded genetics, Sequence Analysis, DNA methods
- Abstract
In Pyrosequencing, the addition of nucleotides to a primer-template hybrid is monitored by enzymatic conversion of chemical energy into detectable light. The technique yields both qualitative and quantitative sequence information because the chemical energy is released by a stoichiometric split off of pyrophosphates from incorporated deoxynucleotide triphosphates and a defined nucleotide dispensation order is given. Because Pyrosequencing works best if single-stranded DNA templates are used, template generation usually requires PCR with a target-specific biotinylated primer and a subsequent purification involving interaction of the biotin label with immobilized streptavidin. To circumvent the need for numerous and expensive template-specific biotinylated primers, we developed a method that uses the ligation of amplified DNA fragments into a plasmid vector, thereby facilitating subsequent PCR using a universal vector-specific biotinylated primer. This approach allows easy and straightforward isolation of single-stranded templates of any PCR product. As a proof of principle, we used the method for genotyping two single-nucleotide polymorphisms in the human genes CARD15 and A2M and for characterization of four multisite variations in the human DEFB104 gene.
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- 2006
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46. The intronic deletion polymorphism of the Alpha2- macroglobulin gene modulates the severity and extent of atherosclerosis in the circle of Willis.
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Larionov S, Dedeck O, Birkenmeier G, Orantes M, Ghebremedhin E, and Thal DR
- Subjects
- Aged, Aged, 80 and over, Genetic Predisposition to Disease, Humans, Introns, Middle Aged, Polymorphism, Genetic, Atherosclerosis genetics, Circle of Willis pathology, alpha-Macroglobulins genetics
- Published
- 2006
- Full Text
- View/download PDF
47. Polymyxin B-conjugated alpha 2-macroglobulin as an adjunctive therapy to sepsis: Modes of action and impact on lethality.
- Author
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Birkenmeier G, Nicklisch S, Pockelt C, Mossie A, Steger V, Gläser C, Hauschildt S, Usbeck E, Huse K, Sack U, Bauer M, and Schäfer A
- Subjects
- Animals, Anti-Bacterial Agents toxicity, Bacterial Infections mortality, Bacterial Infections prevention & control, Blotting, Western, Cell Separation, Chronic Disease, Cytokines metabolism, Dextrans therapeutic use, Dextrans toxicity, Female, Fibroblasts drug effects, Fibroblasts metabolism, Humans, Immunohistochemistry, Inflammation chemically induced, Inflammation drug therapy, Limulus Test, Lipopolysaccharides, Mice, Mice, Inbred BALB C, Polymyxin B toxicity, Receptors, Cytokine metabolism, Receptors, Drug metabolism, Sepsis chemically induced, Sepsis mortality, Tumor Necrosis Factor-alpha metabolism, alpha-Macroglobulins toxicity, Anti-Bacterial Agents therapeutic use, Polymyxin B therapeutic use, Sepsis drug therapy, alpha-Macroglobulins therapeutic use
- Abstract
A drug targeting both the inflammatory initiators (lipopolysaccharide; LPS) and mediators [tumor necrosis factor-alpha (TNF-alpha)] should have advantage over a "single-factor targeting strategy" in sepsis prevention trials. We have prepared conjugates of polymyxin B (PMB) and the cytokine binding protein alpha2-macroglobulin (A2M). The conjugate binds TNF-alpha as well as LPS as studied by electrophoresis and phase partitioning. Compared with free PMB, the conjugate is nontoxic to cells and does not affect the viability of human monocytes. The A2M-PMB conjugate binds to the A2M receptor (CD91/low-density lipoprotein receptor-related protein 1) with affinity similar to that of the nonmodified protein. Fluorescein isothiocyanate-labeled LPS in the presence of A2M-PMB is rapidly transported into fibroblasts for degradation via receptor-mediated endocytosis. In vitro, A2M-PMB demonstrated inhibition of LPS-induced secretion of TNF-alpha from isolated monocytes as well as in the whole blood assay. The efficacy of the drug was tested in mice after induction of acute inflammation (LPS model) and after induction of a polymicrobial sepsis by cecal ligation and puncture (CLP) model. Treatment of mice with A2M-PMB up to 250 microg/g body weight was not toxic to the animal. When the drug was administered 30 min before or 30 min after the LPS challenge, a survival rate of 90 and 70%, respectively, was obtained compared with the placebo control group (5%). A2M-PMB also protected mice after induction of polymicrobial sepsis when administered 30 min before CLP. These results support our hypothesis that A2M-PMB acts as a polyvalent drug to target different host mediators as well as sepsis inducer at the same time.
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- 2006
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48. Effect of alpha2-macroglobulin on retinal glial cell proliferation.
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Milenkovic I, Birkenmeier G, Wiedemann P, Reichenbach A, and Bringmann A
- Subjects
- Adenosine Triphosphate pharmacology, Animals, Bromodeoxyuridine, Cells, Cultured, Epidermal Growth Factor pharmacology, Guinea Pigs, Male, Neuropeptide Y pharmacology, Platelet-Derived Growth Factor pharmacology, Protein-Tyrosine Kinases metabolism, Receptors, G-Protein-Coupled agonists, Cell Proliferation drug effects, Neuroglia cytology, Retina cytology, alpha-Macroglobulins pharmacology
- Abstract
Background: Activation of the receptor for alpha2-macroglobulin (alpha2 M), the low-density lipoprotein-related protein (LRP1; CD91), has been suggested to represent a possible strategy for the inhibition of uncontrolled retinal cell proliferation via stimulation of the clearance of alpha2 M-bound growth factors and proteinases from the extracellular space. In order to prove this assumption, we investigated the effect of alpha2 M on the proliferation of Müller glial cells in vitro., Methods: Proliferation assays using bromodeoxyuridine were carried out on cultured Müller glial cells of the guinea pig in the absence and presence of alpha2 M., Results: Activated alpha2 M evoked a slight increase of the cell proliferation at control conditions. Addition of alpha2 M to the culture medium inhibited the proliferation evoked by agonists of G-protein-coupled receptors [adenosine 5'-triphosphate (ATP), neuropeptide Y]. However, alpha2 M did not diminish the proliferation evoked by agonists of receptor tyrosine kinases (epidermal and platelet-derived growth factors) and by serum, respectively. Inhibition of LRP1 by a neutralizing antibody did not alter the ATP-evoked proliferation while it increased the proliferation in the presence of alpha2 M., Conclusion: It is concluded that alpha2 M inhibits the proliferation evoked by agonists of G-protein-coupled receptors, possibly via enhanced growth factor clearance by LRP.
- Published
- 2005
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49. The human FGF2 level is influenced by genetic predisposition.
- Author
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Schulz S, Köhler K, Schagdarsurengin U, Greiser P, Birkenmeier G, Müller-Werdan U, Werdan K, and Gläser C
- Subjects
- Female, Fibroblast Growth Factor 2 genetics, Genetic Predisposition to Disease, Humans, Male, Middle Aged, Polymorphism, Genetic, RNA, Messenger metabolism, Risk Factors, Severity of Illness Index, Coronary Artery Disease blood, Coronary Artery Disease genetics, Fibroblast Growth Factor 2 metabolism
- Abstract
Background: The fibroblast growth factor 2 (FGF2) is involved in various processes possibly leading to the development of complex diseases such as atherosclerosis. In recent studies, its cardioprotective properties, due to its ability to stimulate the proliferation of collateral vessels, could be shown., Study Design: In this clinical study, the relation between clinical risk markers, a genomic variant of FGF2, namely the c.223C>T polymorphism, and the in vivo FGF2 expression was evaluated. Therefore, 198 clinically well-characterized probands, all of Caucasian origin, were included. The FGF2 mRNA level was determined in monocytes by competitive RT-PCR, whereas the plasma level of circulating FGF2 protein was analysed by ELISA. By considering the angiographically proven stenotic state of the patient, a significant increase in FGF2 mRNA, but not in protein level, could be shown for patients with significant stenosis. Apart from this, no influence on FGF2 expression was found in the case of all of the clinical and biochemical markers investigated. However, in the case of the c.223C>T polymorphism, a significant increase in the individual FGF2 mRNA and protein level in CC-carriers was shown. In multivariate analysis, this relation was independent of all other risk markers investigated., Conclusions: Our results suggest that an increase in FGF2 mRNA expression, related to coronary atherosclerosis, may be necessary for the maintenance of the individual FGF2 plasma level. Since the individual FGF2 mRNA and protein level are, to a large extent, triggered off by genetic background, the FGF2 expression cannot be referred to as an independent clinical marker for CAD.
- Published
- 2005
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50. Characterization of novel monoclonal antibodies for prostate-specific antigen (PSA) with potency to recognize PSA bound to alpha 2-macroglobulin.
- Author
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Baumgart Y, Otto A, Schäfer A, Usbeck E, Cott C, Schott A, Tornack M, Wenzel A, Mossie A, and Birkenmeier G
- Subjects
- Animals, Antibodies, Monoclonal biosynthesis, Antibodies, Monoclonal chemistry, Binding, Competitive, Enzyme-Linked Immunosorbent Assay, Epitopes, Female, Immunoassay, Mice, Mice, Inbred BALB C, Models, Molecular, Peptide Library, Protein Binding, Antibodies, Monoclonal immunology, Prostate-Specific Antigen immunology, Prostate-Specific Antigen metabolism, alpha-Macroglobulins immunology, alpha-Macroglobulins metabolism
- Abstract
Background: Different molecular forms of prostate-specific antigen (PSA) have been used to differentiate between benign prostatic hyperplasia and prostate cancer. Detecting PSA bound to endogenous inhibitors such as alpha(1)-antichymotrypsin (ACT) and alpha(2)-macroglobulin (alpha(2)M) is often difficult because of epitope masking or sensitivity problems. Here we report the characterization of four novel mouse monoclonal antibodies (mabs) obtained by immunization with PSA-alpha(2)M complexes. Their ability to detect free PSA and PSA-inhibitor complexes was shown, and their epitopes were analyzed by phage display technology., Methods: The properties of the mabs were studied by competition and sandwich assays and by Western blotting. Epitope mapping was performed by screening of a phage display peptide library., Results: All four mabs recognized free PSA, PSA-ACT, and PSA-alpha(2)M complexes, but to various degrees. With different combinations of mabs in competition experiments, antibodies were identified that enhance binding of other mabs to PSA, forming the molecular basis of a very sensitive assay for the detection of PSA and PSA-ACT complexes. Mabs with highest reactivity for PSA-alpha(2)M were selected to establish an immunoassay for that complex. Western blot analysis revealed that all mabs recognized conformational epitopes of PSA. These findings were supported by phage display results demonstrating mimotopes in the PSA molecule., Conclusion: The results presented here could aid in the further development of clinically relevant assays for PSA and PSA-alpha(2)M complexes.
- Published
- 2005
- Full Text
- View/download PDF
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