85 research outputs found

    Rat Monoclonal Antibodies Specific for LST1 Proteins

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    The LST1 gene is located in the human MHC class III region and encodes transmembrane and soluble isoforms that have been suggested to play a role in the regulation of the immune response and are associated with inflammatory diseases such as rheumatoid arthritis. Here we describe the generation and characterization of the first monoclonal antibodies against LST1. Two hybridoma lines secreting monoclonal antibodies designated 7E2 and 8D12 were established. The 7E2 antibody detects recombinant and endogenous LST1 by Western blot analysis while 8D12 reacts with recombinant and endogenous LST1 in immunoprecipitation and flow cytometry procedures. The newly established antibodies were used to survey LST1 protein expression in human cell lines, which was found to be tightly regulated, allowing the expression of transmembrane isoforms but suppressing soluble isoforms

    Validation of QBF Encodings with Winning Strategies

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    When using a QBF solver for solving application problems encoded to quantified Boolean formulas (QBFs), mainly two things can potentially go wrong: (1) the solver could be buggy and return a wrong result or (2) the encoding could be incorrect. To ensure the correctness of solvers, sophisticated fuzzing and testing techniques have been presented. To ultimately trust a solving result, solvers have to provide a proof certificate that can be independently checked. Much less attention, however, has been paid to the question how to ensure the correctness of encodings. The validation of QBF encodings is particularly challenging because of the variable dependencies introduced by the quantifiers. In contrast to SAT, the solution of a true QBF is not simply a variable assignment, but a winning strategy. For each existential variable x, a winning strategy provides a function that defines how to set x based on the values of the universal variables that precede x in the quantifier prefix. Winning strategies for false formulas are defined dually. In this paper, we provide a tool for validating encodings using winning strategies and interactive game play with a QBF solver. As the representation of winning strategies can get huge, we also introduce validation based on partial winning strategies. Finally, we employ winning strategies for testing if two different encodings of one problem have the same solutions

    Uncoupled evolution of the Polycomb system and deep origin of non-canonical PRC1

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    Polycomb group proteins, as part of the Polycomb repressive complexes, are essential in gene repression through chromatin compaction by canonical PRC1, mono-ubiquitylation of histone H2A by non-canonical PRC1 and tri-methylation of histone H3K27 by PRC2. Despite prevalent models emphasizing tight functional coupling between PRC1 and PRC2, it remains unclear whether this paradigm indeed reflects the evolution and functioning of these complexes. Here, we conduct a comprehensive analysis of the presence or absence of cPRC1, nPRC1 and PRC2 across the entire eukaryotic tree of life, and find that both complexes were present in the Last Eukaryotic Common Ancestor (LECA). Strikingly, ~42% of organisms contain only PRC1 or PRC2, showing that their evolution since LECA is largely uncoupled. The identification of ncPRC1-defining subunits in unicellular relatives of animals and fungi suggests ncPRC1 originated before cPRC1, and we propose a scenario for the evolution of cPRC1 from ncPRC1. Together, our results suggest that crosstalk between these complexes is a secondary development in evolution.</p

    Uncoupled evolution of the Polycomb system and deep origin of non-canonical PRC1

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    Polycomb group proteins, as part of the Polycomb repressive complexes, are essential in gene repression through chromatin compaction by canonical PRC1, mono-ubiquitylation of histone H2A by non-canonical PRC1 and tri-methylation of histone H3K27 by PRC2. Despite prevalent models emphasizing tight functional coupling between PRC1 and PRC2, it remains unclear whether this paradigm indeed reflects the evolution and functioning of these complexes. Here, we conduct a comprehensive analysis of the presence or absence of cPRC1, nPRC1 and PRC2 across the entire eukaryotic tree of life, and find that both complexes were present in the Last Eukaryotic Common Ancestor (LECA). Strikingly, ~42% of organisms contain only PRC1 or PRC2, showing that their evolution since LECA is largely uncoupled. The identification of ncPRC1-defining subunits in unicellular relatives of animals and fungi suggests ncPRC1 originated before cPRC1, and we propose a scenario for the evolution of cPRC1 from ncPRC1. Together, our results suggest that crosstalk between these complexes is a secondary development in evolution

    Acute corneal melt and perforation - A possible complication after riboflavin/UV-A crosslinking (CXL) in keratoconus.

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    Purpose To report two cases of acute corneal melting and perforation requiring emergency penetrating keratoplasty after corneal crosslinking (CXL) in advanced keratoconus. Observations Case 1 was a 34 and case 2 was a 16-year old male, both with progressive keratoconus, who underwent CXL (Dresden protocol). After riboflavin imbibition, patients had a minimal pachymetry of 337 μm and 347 μm, and therefore required stromal swelling by hypoosmolar riboflavin resulting in pachymetries of 470 μm and 422 μm, prior to the 30 minute UV-irradiation with 3mW/cm2. In case 1, on the 7th postoperative day a 4mm linear perforation occurred. Extensive post-hoc examinations revealed no infectious cause. In case 2, a corneal melting developed within 24 hours, from which Staphylococcus aureus was cultured. Conclusions and importance Acute corneal melting and perforation may occur after CXL. Dysfunctional collagen metabolism, atopia, thin preoperative pachymetry and the use of hypoosmolar substances may have initiated this complication in our cases

    TRAIL-R1 and TRAIL-R2 mediate TRAIL-dependent apoptosis in activated primary human B lymphocytes

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    The maintenance of B cell homeostasis requires a tight control of B cell generation, survival, activation, and maturation. In lymphocytes upon activation, increased sensitivity to apoptotic signals helps controlling differentiation and proliferation. The death receptor Fas is important in this context because genetic Fas mutations in humans lead to an autoimmune lymphoproliferative syndrome that is similar to lymphoproliferation observed in Fas-deficient mice. In contrast, the physiological role of TNF-related apoptosis-inducing ligand receptors (TRAIL-Rs) in humans has been poorly studied so far. Indeed, most studies have focused on tumor cell lines and on mouse models whose results are difficult to transpose to primary human B cells. In the present work, the expression of apoptosis-inducing TRAIL-R1 and TRAIL-R2 and of the decoy receptors TRAIL-R3 and TRAIL-R4 was systematically studied in all developmental stages of peripheral B cells isolated from the blood and secondary lymphoid organs. Expression of TRAIL-Rs is modulated along development, with highest levels observed in germinal center B cells. In addition, T-dependent and T-independent signals elicited induction of TRAIL-Rs with distinct kinetics, which differed among B cell subpopulations: switched memory cells rapidly upregulated TRAIL-R1 and -2 upon activation while naïve B cells only reached similar expression levels at later time points in culture. Increased expression of TRAIL-R1 and -2 coincided with a caspase-3-dependent sensitivity to TRAIL-induced apoptosis in activated B cells but not in freshly isolated resting B cells. Finally, both TRAIL-R1 and TRAIL-R2 could signal actively and both contributed to TRAIL-induced apoptosis. In conclusion, this study provides a systematic analysis of the expression of TRAIL-Rs in human primary B cells and of their capacity to signal and induce apoptosis. This dataset forms a basis to further study and understand the dysregulation of TRAIL-Rs and TRAIL expression observed in autoimmune diseases. Additionally, it will be important to foresee potential bystander immunomodulation when TRAIL-R agonists are used in cancer treatment.Fil: Staniek, Julian. Albert Ludwigs University of Freiburg; AlemaniaFil: Lorenzetti, Raquel. Albert Ludwigs University of Freiburg; AlemaniaFil: Heller, Bianca. Albert Ludwigs University of Freiburg; AlemaniaFil: Janowska, Iga. Albert Ludwigs University of Freiburg; AlemaniaFil: Schneider, Pascal. Universite de Lausanne; SuizaFil: Unger, Susanne. Albert Ludwigs University of Freiburg; AlemaniaFil: Warnatz, Klaus. Albert Ludwigs University of Freiburg; AlemaniaFil: Seidl, Maximilian. Albert Ludwigs University of Freiburg; AlemaniaFil: Venhoff, Nils. Albert Ludwigs University of Freiburg; AlemaniaFil: Thiel, Jens. Albert Ludwigs University of Freiburg; AlemaniaFil: Smulski, Cristian Roberto. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Rizzi, Marta. Albert Ludwigs University of Freiburg; Alemani

    Extending the high-voltage operation of Graphite/NCM811 cells by constructing a robust electrode/electrolyte interphase layer

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    The cycling life of layered Ni-rich LiNi1xy_{1-x-y}CoxMny_yO2_2 (NCM, 1-x-y ≥ 0.8) is typically extended by restricting the upper cut-off voltage during cycling to below 4.2 V, sacrificing, however, the untapped additional capacity above the cut-off voltage. To make this additional capacity available, we investigate graphite/LiNi08_{0·8}Co01_{0·1}Mn01_{0·1}O2_2 cells cycled to high upper cut-off voltages up to 4.5 V at high electrode areal capacities of 4.8 mAh/cm2^2 in a standard electrolyte consisting of 1 M lithium hexafluorophosphate (LiPF6_6) in ethylene carbonate and ethylene methyl carbonate (ethylene carbonate:ethylene methyl carbonate = 3:7 vol% + 2% vinylene carbonate). Although the initial capacity reaches 190 mAh/g, the capacity retention after 300 cycles to 4.5 V is only 66%. Employing a combination of tris(trimethylsilyl)phosphite and lithium difluoro(oxalato)borate as electrolyte additives, we demonstrate excellent capacity retention of 85% after 300 cycles to 4.5 V. Moreover, graphite/LiNi08_{0·8}Co0_{0·}1Mn01_{0·1}O2_2 cells with additives show improved capacity retention also at elevated temperatures of 60 °C. A detailed post-mortem analysis reveals the formation of a compact and LiF-rich and B-containing cathode/electrolyte interphase layer on the LiNi08_{0·8}Co01_{0·1}Mn01_{0·1}O2_2 particles cycled with tris(trimethylsilyl)phosphite and lithium difluoro(oxalato)borate additives, substantially suppressing the transition metal dissolution and the cation-disordered layer formation on the exposed particles\u27 surface

    Low-Salt Diet Attenuates B-Cell- and Myeloid-Cell-Driven Experimental Arthritides by Affecting Innate as Well as Adaptive Immune Mechanisms

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    A link between high sodium chloride (salt) intake and the development of autoimmune diseases was previously reported. These earlier studies demonstrated exacerbation of experimental autoimmune encephalomyelitis and colitis by excess salt intake associated with Th17- and macrophage-mediated mechanisms. Little is known about the impact of dietary salt intake on experimental arthritides. Here, we investigated if salt restriction can exert beneficial effects on collagen-induced arthritis (CIA) and K/BxN serum transfer-induced arthritis (STIA). CIA depends on both adaptive and innate immunity, while STIA predominantly mimics the innate immune cell-driven effector phase of arthritis. In both models, low salt (LS) diet significantly decreased arthritis severity compared to regular salt (RS) and high salt (HS) diet. We did not observe an aggravation of arthritis with HS diet compared to RS diet. Remarkably, in STIA, LS diet was as effective as IL-1 receptor blocking treatment. Complement-fixing anti-CII IgG2a antibodies are associated with inflammatory cell infiltration and cartilage destruction. LS diet reduced anti-CII IgG2a levels in CIA and decreased the anti-CII IgG2a/IgG1 ratios pointing toward a more Th2-like response. Significantly less inflammatory joint infiltrates and cartilage breakdown associated with reduced protein concentrations of IL-1 beta (CIA and STIA), IL-17 (CIA), and the monocyte chemoattractant protein-1 (MCP-1) (CIA) were detected in mice receiving LS diet compared to HS diet. However, we did not find a reduced IL-17A expression in CD4+ T cells upon salt restriction in CIA. Analysis of mRNA transcripts and immunoblots revealed a link between LS diet and inhibition of the p38 MAPK (mitogen-activated protein kinase)/NFAT5 (nuclear factor of activated T-cells 5) signaling axis in STIA. Further experiments indicated a decreased leukodiapedesis under LS conditions. In conclusion, dietary salt restriction ameliorates CIA and STIA, indicating a beneficial role of LS diet during both the immunization and effector phase of immune-mediated arthritides by predominantly modulating the humoral immunity and the activation status of myeloid lineage cells. Hence, salt restriction might represent a supportive dietary intervention not only to reduce cardiovascular risk, but also to improve human inflammatory joint diseases like rheumatoid arthritis
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