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Zhang J.,University of Dundee | Clark K.,University of Dundee | Lawrence T.,Center Dimmunologie Of Marseille Luminy | Peggie M.W.,University of Dundee | Cohen P.,University of Dundee
Biochemical Journal | Year: 2014

IKKβ {Iκ B [inhibitor of NF-κB (nuclear factor κB)] kinase β} is required to activate the transcription factor NF-κB, but how IKKβ itself is activated in vivo is still unclear. It was found to require phosphorylation by one or more 'upstream' protein kinases in some reports, but by autophosphorylation in others. In the present study, we resolve this controversy by demonstrating that the activation of IKKβ induced by IL-1 (interleukin-1) or TNF (tumour necrosis factor) in embryonic fibroblasts, or by ligands that activate Toll-like receptors in macrophages, requires two distinct phosphorylation events: first, the TAK1 [TGFβ (transforming growth factor β)-activated kinase-1]-catalysed phosphorylation of Ser 177 and, secondly, the IKKβ-catalysed autophosphorylation of Ser181. The phosphorylation of Ser177 by TAK1 is a priming event required for the subsequent autophosphorylation of Ser181, which enables IKKβ to phosphorylate exogenous substrates. We also provide genetic evidence which indicates that the IL-1-stimulated, LUBAC (linear ubiquitin chain assembly complex)-catalysed formation of linear ubiquitin chains and their interaction with the NEMO (NF-κB essential modulator) component of the canonical IKK complex permits the TAK1-catalysed priming phosphorylation of IKKβ at Ser177 and IKKα at Ser176. These findings may be of general significance for the activation of other protein kinases. © The Authors Journal compilation © 2014 Biochemical Society. Source

Alvarez-Errico D.,Chromatin | Vento-Tormo R.,Chromatin | Sieweke M.,Center Dimmunologie Of Marseille Luminy | Ballestar E.,Chromatin
Nature Reviews Immunology | Year: 2015

Myeloid cells are crucial effectors of the innate immune response and important regulators of adaptive immunity. The differentiation and activation of myeloid cells requires the timely regulation of gene expression; this depends on the interplay of a variety of elements, including transcription factors and epigenetic mechanisms. Epigenetic control involves histone modifications and DNA methylation, and is coupled to lineage-specifying transcription factors, upstream signalling pathways and external factors released in the bone marrow, blood and tissue environments. In this Review, we highlight key epigenetic events controlling myeloid cell biology, focusing on those related to myeloid cell differentiation, the acquisition of myeloid identity and innate immune memory. © 2015 Macmillan Publishers Limited. All rights reserved. Source

Birnbaum D.J.,French Institute of Health and Medical Research | Adelaide J.,French Institute of Health and Medical Research | Mamessier E.,Center Dimmunologie Of Marseille Luminy | Finetti P.,French Institute of Health and Medical Research | And 10 more authors.
Genes Chromosomes and Cancer | Year: 2011

Pancreatic adenocarcinoma is one of the most aggressive human cancers. It displays many different chromosomal abnormalities and mutations. By using 244 K high-resolution array-comparative genomic hybridization (aCGH) we studied the genome alterations of 39 fine-needle aspirations from pancreatic adenocarcinoma and eight human adenocarcinoma pancreatic cell lines. Using both visual inspection and GISTIC analysis, recurrent losses were observed on 1p, 3p, 4p, 6, 8p, 9, 10, 11q, 15q, 17, 18, 19p, 20p, 21, and 22 and comprised several known or suspected tumor suppressor genes such as ARHGEF10, ARID1A, CDKN2A/B, FHIT, PTEN, RB1, RUNX1-3, SMAD4, STK11/LKB1, TP53, and TUSC3. Heterozygous deletion of the 1p35-p36 chromosomal region was identified in one-third of the tumors and three of the cell lines. This region, commonly deleted in human cancers, contains several tumor suppressor genes including ARID1A and RUNX3. We identified frequent genetic gains on chromosome arms 1q, 3q, 5p, 6p, 7q, 8q, 12q, 15q, 18q, 19q, and 20q. Amplifications were observed in 16 tumors. AKT2, CCND3, CDK4, FOXA2, GATA6, MDM2, MYC, and SMURF1 genes were gained or amplified. The most obvious amplification was located at 18q11.2 and targeted the GATA6 gene, which plays a predominant role in the initial specification of the pancreas and in pancreatic cell type differentiation. In conclusion, we have identified novel biomarkers and potential therapeutic targets in pancreatic adenocarcinoma. © 2011 Wiley-Liss, Inc. Source

Koyama M.,Queensland Institute of Medical Research | Kuns R.D.,Queensland Institute of Medical Research | Olver S.D.,Queensland Institute of Medical Research | Raffelt N.C.,Queensland Institute of Medical Research | And 14 more authors.
Nature Medicine | Year: 2012

The presentation pathways by which allogeneic peptides induce graft-versus-host disease (GVHD) are unclear. We developed a bone marrow transplant (BMT) system in mice whereby presentation of a processed recipient peptide within major histocompatibility complex (MHC) class II molecules could be spatially and temporally quantified. Whereas donor antigen presenting cells (APCs) could induce lethal acute GVHD via MHC class II, recipient APCs were 100-1,000 times more potent in this regard. After myeloablative irradiation, T cell activation and memory differentiation occurred in lymphoid organs independently of alloantigen. Unexpectedly, professional hematopoietic-derived recipient APCs within lymphoid organs had only a limited capacity to induce GVHD, and dendritic cells were not required. In contrast, nonhematopoietic recipient APCs within target organs induced universal GVHD mortality and promoted marked alloreactive donor T cell expansion within the gastrointestinal tract and inflammatory cytokine generation. These data challenge current paradigms, suggesting that experimental lethal acute GVHD can be induced by nonhematopoietic recipient APCs. © 2012 Nature America, Inc. All rights reserved. Source

Signorino G.,Messina University | Mohammadi N.,Messina University | Patane F.,Messina University | Buscetta M.,Messina University | And 8 more authors.
Infection and Immunity | Year: 2014

Murine Toll-like receptor 13 (TLR13), an endosomal receptor that is not present in humans, is activated by an unmethylated motif present in the large ribosomal subunit of bacterial RNA (23S rRNA). Little is known, however, of the impact of TLR13 on antibacterial host defenses. Here we examined the role of this receptor in the context of infection induced by the model pathogen group B streptococcus (GBS). To this end, we used bacterial strains masked from TLR13 recognition by virtue of constitutive expression of the ErmC methyltransferase, which results in dimethylation of the 23S rRNA motif at a critical adenine residue. We found that TLR13-mediated rRNA recognition was required for optimal induction of tumor necrosis factor alpha and nitrous oxide in dendritic cell and macrophage cultures stimulated with heat-killed bacteria or purified bacterial RNA. However, TLR13-dependent recognition was redundant when live bacteria were used as a stimulus. Moreover, masking bacterial rRNA from TLR13 recognition did not increase the ability of GBS to avoid host defenses and replicate in vivo. In contrast, increased susceptibility to infection was observed under conditions in which signaling by all endosomal TLRs was abolished, i.e., in mice with a loss-of-function mutation in the chaperone protein UNC93B1. Our data lend support to the conclusion that TLR13 participates in GBS recognition, although blockade of the function of this receptor can be compensated for by other endosomal TLRs. Lack of selective pressure by bacterial infections might explain the evolutionary loss of TLR13 in humans. However, further studies using different bacterial species are needed to prove this hypothesis. © 2014, American Society for Microbiology. Source

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