117 research outputs found

    Elevated A20 promotes TNF-induced and RIPK1-dependent intestinal epithelial cell death

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    Intestinal epithelial cell (IEC) death is a common feature of inflammatory bowel disease (IBD) that triggers inflammation by compromising barrier integrity. In many patients with IBD, epithelial damage and inflammation are TNF-dependent. Elevated TNF production in IBD is accompanied by increased expression of the TNFAIP3 gene, which encodes A20, a negative feedback regulator of NF-κB. A20 in intestinal epithelium from patients with IBD coincided with the presence of cleaved caspase-3, and A20 transgenic (Tg) mice, in which A20 is expressed from an IEC-specific promoter, were highly susceptible to TNF-induced IEC death, intestinal damage, and shock. A20-expressing intestinal organoids were also susceptible to TNF-induced death, demonstrating that enhanced TNF-induced apoptosis was a cell-autonomous property of A20. This effect was dependent on Receptor Interacting Protein Kinase 1 (RIPK1) activity, and A20 was found to associate with the Ripoptosome complex, potentiating its ability to activate caspase-8. A20-potentiated RIPK1-dependent apoptosis did not require the A20 deubiquitinase (DUB) domain and zinc finger 4 (ZnF4), which mediate NF-κB inhibition in fibroblasts, but was strictly dependent on ZnF7 and A20 dimerization. We suggest that A20 dimers bind linear ubiquitin to stabilize the Ripoptosome and potentiate its apoptosis-inducing activity

    RIPK1 Mediates TNF-Induced Intestinal Crypt Apoptosis During Chronic NF-κB Activation

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    Tumor necrosis factor (TNF) is a major pathogenic effector and a therapeutic target in inflammatory bowel disease (IBD), yet the basis for TNF-induced intestinal epithelial cell (IEC) death is unknown, because TNF does not kill normal IECs. Here, we investigated how chronic nuclear factor (NF)- κB activation, which occurs in human IBD, promotes TNF-dependent IEC death in mice. Human IBD specimens were stained for p65 and cleaved caspase-3. C57BL/6 mice with constitutively active IKKβ in IEC (Ikkβ(EE) IEC ), Ripk1 D138N/D138N knockin mice, and Ripk3 -/- mice were injected with TNF or lipopolysaccharide. Enteroids were also isolated from these mice and challenged with TNF with or without RIPK1 and RIPK3 inhibitors or butylated hydroxyanisole. Ripoptosome-mediated caspase-8 activation was assessed by immunoprecipitation. NF-κB activation in human IBD correlated with appearance of cleaved caspase-3. Congruently, unlike normal mouse IECs that are TNF-resistant, IECs in Ikkβ(EE) IEC mice and enteroids were susceptible to TNF-dependent apoptosis, which depended on the protein kinase function of RIPK1. Constitutively active IKKβ facilitated ripoptosome formation, a RIPK1 signaling complex that mediates caspase-8 activation by TNF. Butylated hydroxyanisole treatment and RIPK1 inhibitors attenuated TNF-induced and ripoptosome-mediated caspase-8 activation and IEC death in vitro and in vivo. Contrary to common expectations, chronic NF-κB activation induced intestinal crypt apoptosis after TNF stimulation, resulting in severe mucosal erosion. RIPK1 kinase inhibitors selectively inhibited TNF destructive properties while preserving its survival and proliferative properties, which do not require RIPK1 kinase activity. RIPK1 kinase inhibition could be a potential treatment for IBD

    A daily-updated tree of (sequenced) life as a reference for genome research

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    We report a daily-updated sequenced/species Tree Of Life (sTOL) as a reference for the increasing number of cellular organisms with their genomes sequenced. The sTOL builds on a likelihood-based weight calibration algorithm to consolidate NCBI taxonomy information in concert with unbiased sampling of molecular characters from whole genomes of all sequenced organisms. Via quantifying the extent of agreement between taxonomic and molecular data, we observe there are many potential improvements that can be made to the status quo classification, particularly in the Fungi kingdom; we also see that the current state of many animal genomes is rather poor. To augment the use of sTOL in providing evolutionary contexts, we integrate an ontology infrastructure and demonstrate its utility for evolutionary understanding on: nuclear receptors, stem cells and eukaryotic genomes. The sTOL (http://supfam.org/SUPERFAMILY/ sTOL) provides a binary tree of (sequenced) life, and contributes to an analytical platform linking genome evolution, function and phenotype

    Analysis of the Human Kinome Using Methods Including Fold Recognition Reveals Two Novel Kinases

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    Background: Protein sequence similarity is a commonly used criterion for inferring the unknown function of a protein from a protein of known function. However, proteins can diverge significantly over time such that sequence similarity is difficult, if not impossible, to find. In some cases, a structural similarity remains over long evolutionary time scales and once detected can be used to predict function. Methodology/Principal Findings: Here we employed a high-throughput approach to assign structural and functional annotation to the human proteome, focusing on the collection of human protein kinases, the human kinome. We compared human protein sequences to a library of domains from known structures using WU-BLAST, PSI-BLAST, and 123D. This approach utilized both sequence comparison and fold recognition methods. The resulting set of potential protein kinases was cross-checked against previously identified human protein kinases, and analyzed for conserved kinase motifs. Conclusions/Significance: We demonstrate that our structure-based method can be used to identify both typical and atypical human protein kinases. We also identify two potentially novel kinases that contain an interesting combination o

    Developing a Personality Model for Speech-based Conversational Agents Using the Psycholexical Approach

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    We present the first systematic analysis of personality dimensions developed specifically to describe the personality of speech-based conversational agents. Following the psycholexical approach from psychology, we first report on a new multi-method approach to collect potentially descriptive adjectives from 1) a free description task in an online survey (228 unique descriptors), 2) an interaction task in the lab (176 unique descriptors), and 3) a text analysis of 30,000 online reviews of conversational agents (Alexa, Google Assistant, Cortana) (383 unique descriptors). We aggregate the results into a set of 349 adjectives, which are then rated by 744 people in an online survey. A factor analysis reveals that the commonly used Big Five model for human personality does not adequately describe agent personality. As an initial step to developing a personality model, we propose alternative dimensions and discuss implications for the design of agent personalities, personality-aware personalisation, and future research.Comment: 14 pages, 2 figures, 3 tables, CHI'2

    A Pan-cancer analysis reveals high-frequency genetic alterations in mediators of signaling by the tgf-β superfamily

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    We present an integromic analysis of gene alterations that modulate transforming growth factor β (TGF-β)-Smad-mediated signaling in 9,125 tumor samples across 33 cancer types in The Cancer Genome Atlas (TCGA). Focusing on genes that encode mediators and regulators of TGF-β signaling, we found at least one genomic alteration (mutation, homozygous deletion, or amplification) in 39% of samples, with highest frequencies in gastrointestinal cancers. We identified mutation hotspots in genes that encode TGF-β ligands (BMP5), receptors (TGFBR2, AVCR2A, and BMPR2), and Smads (SMAD2 and SMAD4). Alterations in the TGF-β superfamily correlated positively with expression of metastasis-associated genes and with decreased survival. Correlation analyses showed the contributions of mutation, amplification, deletion, DNA methylation, and miRNA expression to transcriptional activity of TGF-β signaling in each cancer type. This study provides a broad molecular perspective relevant for future functional and therapeutic studies of the diverse cancer pathways mediated by the TGF-β superfamily

    Spiritual Care in General Practice : Rushing in or fearing to tread? An Integrative Review of Qualitative Literature

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    Acknowledgements Thanks to Jenny Jones, Stirling University, Rod Sampson and Melanie Bickerton, and Nicola Ring, University of Stirling. Funding A bursary from the University of Aberdeen was awarded. Ethical approval is not required. Open access via Springer CompactPeer reviewedPublisher PD
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