19 research outputs found

    Base-modified UDP-sugars reduce cell surface levels of P-selectin glycoprotein 1 (PSGL-1) on IL-1Îē-stimulated human monocytes

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    P-selectin glycoprotein ligand-1 (PSGL-1, CD162) is a cell-surface glycoprotein that is expressed, either constitutively or inducibly, on all myeloid and lymphoid cell lineages. PSGL-1 is implicated in cell–cell interactions between platelets, leukocytes and endothelial cells, and a key mediator of inflammatory cell recruitment and transmigration into tissues. Here, we have investigated the effects of the Îē-1,4-galactosyltransferase inhibitor 5-(5-formylthien-2-yl) UDP-Gal (5-FT UDP-Gal, compound 1) and two close derivatives on the cell surface levels of PSGL-1 on human peripheral blood mononuclear cells (hPBMCs). PSGL-1 levels were studied both under basal conditions, and upon stimulation of hPBMCs with interleukin-1Îē (IL-1Îē). Between 1 and 24 hours after IL-1Îē stimulation, we observed initial PSGL-1 shedding, followed by an increase in PSGL-1 levels on the cell surface, with a maximal window between IL-1Îē-induced and basal levels after 72 h. All three inhibitors reduce PSGL-1 levels on IL-1Îē-stimulated cells in a concentration-dependent manner, but show no such effect in resting cells. Compound 1 also affects the cell surface levels of adhesion molecule CD11b in IL-1Îē-stimulated hPBMCs, but not of glycoproteins CD14 and CCR2. This activity profile may be linked to the inhibition of global Sialyl Lewis presentation on hPBMCs by compound 1, which we have also observed. Although this mechanistic explanation remains hypothetical at present, our results show, for the first time, that small molecules can discriminate between IL-1Îē-induced and basal levels of cell surface PSGL-1. These findings open new avenues for intervention with PSGL-1 presentation on the cell surface of primed hPBMCs and may have implications for anti-inflammatory drug development

    Uncharged nucleoside inhibitors of Îē-1,4-galactosyltransferase with activity in cells

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    5-Substituted uridine derivatives are uncharged galactosyltransferase inhibitors that reduce PSGL-1 expression in human monocytes.</p

    Pulmonary vascular changes in asthma and COPD

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    In chronic lung disorders such as in asthma and chronic obstructive pulmonary disease (COPD) there is increased bronchial angiogenesis and remodelling of pulmonary vessels culminating to altered bronchial and pulmonary circulation. The involvement of residential cells such as endothelial cells, smooth muscle cells and pulmonary fibroblasts, all appear to have a crucial role in the progression of vascular inflammation and remodelling. The regulatory abnormalities, growth factors and mediators implicated in the pulmonary vascular changes of asthma and COPD subjects and potential therapeutic targets have been described in this review

    Smooth muscle in tissue remodeling and hyper-reactivity:Airways and arteries

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    Smooth muscle comprises a key functional component of both the airways and their supporting vasculature. Dysfunction of smooth muscle contributes to and exacerbates a host of breathing-associated pathologies such as asthma, chronic obstructive pulmonary disease and pulmonary hypertension. These diseases may be marked by airway and/or vascular smooth muscle hypertrophy, proliferation and hyper-reactivity, and related conditions such as fibrosis and extracellular matrix remodeling. This review will focus on the contribution of airway or vascular smooth dysfunction to common airway diseases

    Brain Natriuretic Peptide Protects against Hyperresponsiveness of Human Asthmatic Airway Smooth Muscle via an Epithelial Cell-Dependent Mechanism

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    Brain natriuretic peptide (BNP) relaxes airways by activating natriuretic peptide receptor-A and elevating cyclic guanosine monophosphate. BNP is more effective in passively sensitized human bronchi compared with control airways. The molecular and cellular patterns involved in this signaling are unknown. The aim of this study was to investigate the influence of BNP on airway smooth muscle (ASM) cells obtained from donors with asthma and healthy donors and to identify the mechanisms involved in BNP-mediated relaxation. The contractile response ofASMcells was microscopically assessed in vitro in the presence of 1 mM BNP or with supernatant from human bronchial epithelial (BEAS-2B) cells pretreated with 1 mM BNP. We investigated the role of muscarinic M2 receptors and inducible nitric oxide synthase (iNOS), quantified the release of acetylcholine and nitric oxide (NO), and assessed the gene/protein expression of iNOS and myosin phosphatase target subunit 1 (MYPT1). Supernatant from BEAS-2B cells treated with BNP reduced the hyperreactivity of asthmatic ASM cells by shifting the potency of histamine by 1.19-fold but had no effect in healthy ASM cells. BNP was not effective directly on ASM cells. Blocking muscarinic M2-receptors and iNOS abolished the protective role of supernatant from BEAS-2B treated with BNP. BNP stimulated the release of acetylcholine (210.7 +/- 11.1%) from BEAS-2B cells that in turn increased MYPT1 and iNOS gene/protein expression and enhanced NO levels in asthmatic ASM supernatant (35.0 +/- 13.0%). This study provides evidence that BNP protects against bronchial hyperresponsiveness via an interaction between respiratory epithelium and ASM in subjects with asthma.</p
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