89 research outputs found

    Benzothiazolium salts as reagents for the deoxygenative perfluoroalkylthiolation of alcohols

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    A series of 2-(perfluoroalkylthio)benzothiazolium (BT-SRF) salts have been synthesized that serve as convenient sources of hitherto underexplored perfluoroalkylthiolate anions. An investigation of their reactivity in a deoxygenative nucleophilic substitution reaction led to the development of an unprecedented process that provides pentafluoroethyl and heptafluoropropyl thioethers directly from readily available alcohols

    Formal Insertion of Alkenes Into C(sp3)−F Bonds Mediated by Fluorine-Hydrogen Bonding

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    C−F Insertion reactions represent an attractive approach to prepare valuable fluorinated compounds. The high strength of C−F bonds and the low reactivity of the fluoride released upon C−F bond cleavage, however, mean that examples of such processes are extremely scarce in the literature. Here we report a reaction system that overcomes these challenges using hydrogen bond donors that both activate C−F bonds and allow for downstream reactions with fluoride. In the presence of hexafluoroisopropanol, benzyl and propargyl fluorides undergo efficient formal C−F bond insertion across α-fluorinated styrenes. This process, which does not require any additional fluorinating reagent, occurs under mild conditions and delivers products featuring the gem-difluoro motif, which is attracting increasing interest in medicinal chemistry. Moreover, readily available organic bromides can be engaged directly in a one-pot process that avoids the isolation of organic fluorides

    The IL-20 cytokine family in rheumatoid arthritis and spondyloarthritis

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    This review describes the IL-20 family of cytokines in rheumatoid arthritis (RA) and spondyloartrhitits (SpA) including psoriatic arthritis. The IL-20 receptor (R) cytokines IL-19, IL-20 and IL-24 are produced both in the peripheral blood and in the synovial joint and are induced by Toll-like receptor ligands and autoantibody associated immune complexes in monocytes. IL-19 seems to have anti-inflammatory functions in arthritis. In contrast, IL-20 and IL-24 increase the production of proinflammatory molecules such as monocyte chemoattractant protein 1 and are associated with bone degradation and radiographic progression. IL-22 is also associated with progression of bone erosions. This suggests that the IL-22RA1 subunit shared by IL-20, IL-22 and IL-24 is important for bone homeostasis. In line with this, the IL-22RA1 has been found on preosteoclasts in early RA. IL-26 is produced in high amounts by myofibroblasts and IL-26 stimulation of monocytes has been shown to be an important inducer of Th17 cells in RA. This indicates a role for IL-26 as an important factor in the interactions between resident synovial cells and infiltrating leukocytes. The strategy for modulating the IL-20 cytokine family should take into account the overlap in cellular sources and effector mechanisms. The redundancy encourages inhibition of more than one cytokine or one of the shared receptors. All IL-20 family members utilize the Janus kinase signaling pathway and are therefore potentially inhibited by drugs targeting these enzymes

    Identification of Candida glabrata genes involved in pH modulation and modification of the phagosomal environment in macrophages

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    notes: PMCID: PMC4006850types: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov'tCandida glabrata currently ranks as the second most frequent cause of invasive candidiasis. Our previous work has shown that C. glabrata is adapted to intracellular survival in macrophages and replicates within non-acidified late endosomal-stage phagosomes. In contrast, heat killed yeasts are found in acidified matured phagosomes. In the present study, we aimed at elucidating the processes leading to inhibition of phagosome acidification and maturation. We show that phagosomes containing viable C. glabrata cells do not fuse with pre-labeled lysosomes and possess low phagosomal hydrolase activity. Inhibition of acidification occurs independent of macrophage type (human/murine), differentiation (M1-/M2-type) or activation status (vitamin D3 stimulation). We observed no differential activation of macrophage MAPK or NFκB signaling cascades downstream of pattern recognition receptors after internalization of viable compared to heat killed yeasts, but Syk activation decayed faster in macrophages containing viable yeasts. Thus, delivery of viable yeasts to non-matured phagosomes is likely not triggered by initial recognition events via MAPK or NFκB signaling, but Syk activation may be involved. Although V-ATPase is abundant in C. glabrata phagosomes, the influence of this proton pump on intracellular survival is low since blocking V-ATPase activity with bafilomycin A1 has no influence on fungal viability. Active pH modulation is one possible fungal strategy to change phagosome pH. In fact, C. glabrata is able to alkalinize its extracellular environment, when growing on amino acids as the sole carbon source in vitro. By screening a C. glabrata mutant library we identified genes important for environmental alkalinization that were further tested for their impact on phagosome pH. We found that the lack of fungal mannosyltransferases resulted in severely reduced alkalinization in vitro and in the delivery of C. glabrata to acidified phagosomes. Therefore, protein mannosylation may play a key role in alterations of phagosomal properties caused by C. glabrata.Deutsche ForschungsgemeinschaftNational Institutes for HealthWellcome TrustBBSR

    Integrating Signals from the T-Cell Receptor and the Interleukin-2 Receptor

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    T cells orchestrate the adaptive immune response, making them targets for immunotherapy. Although immunosuppressive therapies prevent disease progression, they also leave patients susceptible to opportunistic infections. To identify novel drug targets, we established a logical model describing T-cell receptor (TCR) signaling. However, to have a model that is able to predict new therapeutic approaches, the current drug targets must be included. Therefore, as a next step we generated the interleukin-2 receptor (IL-2R) signaling network and developed a tool to merge logical models. For IL-2R signaling, we show that STAT activation is independent of both Src- and PI3-kinases, while ERK activation depends upon both kinases and additionally requires novel PKCs. In addition, our merged model correctly predicted TCR-induced STAT activation. The combined network also allows information transfer from one receptor to add detail to another, thereby predicting that LAT mediates JNK activation in IL-2R signaling. In summary, the merged model not only enables us to unravel potential cross-talk, but it also suggests new experimental designs and provides a critical step towards designing strategies to reprogram T cells

    The role of thymic tolerance in CNS autoimmune disease

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    The contributions of the peripheral adaptive and innate immune systems to CNS autoimmunity have been extensively studied. However, the role of thymic selection in these conditions is much less well understood. The thymus is the primary lymphoid organ for the generation of T cells; thymic mechanisms ensure that cells with an overt autoreactive specificity are eliminated before they emigrate to the periphery and control the generation of thymic regulatory T cells. Evidence from animal studies demonstrates that thymic T cell selection is important for establishing tolerance to autoantigens. However, there is a considerable knowledge gap regarding the role of thymic selection in autoimmune conditions of the human CNS. In this Review, we critically examine the current body of experimental evidence for the contribution of thymic tolerance to CNS autoimmune diseases. An understanding of why dysfunction of either thymic or peripheral tolerance mechanisms rarely leads to CNS inflammation is currently lacking. We examine the potential of de novo T cell formation and thymic selection as novel therapeutic avenues and highlight areas for future study that are likely to make these targets the focus of future treatments
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