91 research outputs found

    Low CD73 expression on synovial lymphocytes correlates with reduced adenosine generation and higher disease severity in juvenile idiopathic arthritis

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    Objective To investigate the expression and the adenosine-generating activity of the ecto-5'-nucleotidase CD73 on synovial fluid mononuclear cells (SFMC) and peripheral blood mononuclear cells (PBMC) from children with arthritis. Methods Given the role of CD73 protein in the production of anti-inflammatory adenosine which intersects with inflammatory biology, its expression on lymphocytes was determined by flow cytometry. The CD73 AMPase activity of PBMC and SFMC was measured by HPLC. The effects of cell activation on CD73 expression were examined by in vitro culture of PBMC. Results CD8+ and CD19+ synovial lymphocytes from patients with juvenile idiopathic arthritis (JIA) expressed decreased levels of CD73 compared to both paired JIA PBMC and those from healthy controls. When comparing percentages of CD73+ synovial fluid lymphocytes in the two clinical forms of oligoarthritis, those with extended oligoarthritis showed lower CD73 expression compared to patients with the milder form of disease. Synovial CD8+ T cells had a lower ability to produce adenosine from Etheno-AMP compared to CD8+ PBMC. T cell activation through the TCR of CD8+CD73+ cells and B cell activation through TLR9 resulted in reduced expression of CD73. This downregulation occurred on dividing cells. Conclusion These data show that low CD73 expression on T and B cells in the inflammatory site is related to cell proliferation and is correlated with the clinical severity of oligoarticular JIA. The decreased CD73 expression on SFMC in turn results in reduced adenosine production, which would lead to decreased potential for anti-inflammatory activity

    Th1 and Th17 cell subpopulations are enriched in the peripheral blood of patients with systemic juvenile idiopathic arthritis

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    The role of the adaptive immune system has not been explored in detail compared with the innate immune system in systemic JIA (sJIA) pathogenesis. The aim of this study was to examine the phenotype of circulating peripheral blood CD4(+) T-cell subpopulations in a cross-sectional study of sJIA patients during disease remission on medication and during acute flare of the disease

    The Tandem CARDs of NOD2: Intramolecular Interactions and Recognition of RIP2

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    Caspase recruitment domains (CARDs) are homotypic protein interaction modules that link the stimulus-dependent assembly of large signaling platforms such as inflammasomes to the activation of downstream effectors that often include caspases and kinases and thereby play an important role in the regulation of inflammatory and apoptotic signaling pathways. NOD2 belongs to the NOD-like (NLR) family of intracellular pattern recognition receptors (PRR) and induces activation of the NF-κB pathway in response to the recognition of bacterial components. This process requires the specific recognition of the CARD of the protein kinase RIP2 by the tandem CARDs of NOD2. Here we demonstrate that the tandem CARDs of NOD2 are engaged in an intramolecular interaction that is important for the structural stability of this region. Using a combination of ITC and pull-down experiments we identify distinct surface areas that are involved in the intramolecular tandem CARD interaction and the interaction with the downstream effector RIP2. Our findings indicate that while CARDa of NOD2 might be the primary binding partner of RIP2 the two CARDs of NOD2 do not act independently of one another but may cooperate to from a binding surface that is distinct from that of single CARDs

    On computational approaches for size-and-shape distributions from sedimentation velocity analytical ultracentrifugation

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    Sedimentation velocity analytical ultracentrifugation has become a very popular technique to study size distributions and interactions of macromolecules. Recently, a method termed two-dimensional spectrum analysis (2DSA) for the determination of size-and-shape distributions was described by Demeler and colleagues (Eur Biophys J 2009). It is based on novel ideas conceived for fitting the integral equations of the size-and-shape distribution to experimental data, illustrated with an example but provided without proof of the principle of the algorithm. In the present work, we examine the 2DSA algorithm by comparison with the mathematical reference frame and simple well-known numerical concepts for solving Fredholm integral equations, and test the key assumptions underlying the 2DSA method in an example application. While the 2DSA appears computationally excessively wasteful, key elements also appear to be in conflict with mathematical results. This raises doubts about the correctness of the results from 2DSA analysis
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