Regulation of the transcriptional program by DNA methylation during human αβ T-cell development

© The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research. Thymocyte differentiation is a complex process involving well-defined sequential developmental stages that ultimately result in the generation of mature T-cells. In this study, we analyzed DNA methylation and gene expression profiles at successive human thymus developmental stages. Gain and loss of methylation occurred during thymocyte differentiation, but DNA demethylation was much more frequent than de novo methylation and more strongly correlated with gene expression. These changes took place in CpG-poor regions and were closely associated with T-cell differentiation and TCR function. Up to 88 genes that encode transcriptional regulators, some of whose functions in T-cell development are as yet unknown, were differentially methylated during differentiation. Interestingly, no reversion of accumulated DNA methylation changes was observed as differentiation progressed, except in a very small subset of key genes (RAG1, RAG2, CD8A, PTCRA, etc.), indicating that methylation changes are mostly unique and irreversible events. Our study explores the contribution of DNA methylation to T-cell lymphopoiesis and provides a fine-scale map of differentially methylated regions associated with gene expression changes. These can lay the molecular foundations for a better interpretation of the regulatory networks driving human thymopoiesis.Plan Nacional de [I+D+I 2008–2011]; Instituto de Salud Carlos III [grant number PI12/02587]; Red Española de Investigación Renal (REDinREN) [grant number RD12/0021/0018 and RD12/0021/0021]; Spanish Ministry of Science and Innovation [grant number SAF2010- 15106 and PLE2009-0110]; European Union [Fondos FEDER]Peer Reviewe

The DC-SIGN–related lectin LSECtin mediates antigen capture and pathogen binding by human myeloid cells

7 Figures. Conflict-of-interest disclosure: The authors declare no competing financial interests. The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked ‘‘advertisement’’ in accordance with 18 USC section 1734.Liver and lymph node sinusoidal endothelial cell C-type lectin (LSECtin [CLEC4G]) is a C-type lectin encoded within the liver/lymph node–specific intercellular adhesion molecule-3–grabbing nonintegrin (L-SIGN)/dendritic cell–specific intercellular adhesion molecule-3–grabbing nonintegrin (DC-SIGN)/CD23 gene cluster. LSECtin expression has been previously described as restricted to sinusoidal endothelial cells of the liver and lymph node. We now report LSECtin expression in human peripheral blood and thymic dendritic cells isolated ex vivo. LSECtin is also detected in monocyte-derived macrophages and dendritic cells at the RNA and protein level. In vitro, interleukin-4 (IL-4) induces the expression of 3 LSECtin alternatively spliced isoforms, including a potentially soluble form (Δ2 isoform) and a shorter version of the prototypic molecule (Δ3/4 isoform). LSECtin functions as a pathogen receptor, because its expression confers Ebola virus–binding capacity to leukemic cells. Sugar-binding studies indicate that LSECtin specifically recognizes N-acetyl-glucosamine, whereas no LSECtin binding to Mannan- or N-acetyl-galactosamine–containing matrices are observed. Antibody or ligand-mediated engagement triggers a rapid internalization of LSECtin,which is dependent on tyrosine and diglutamic-containing motifs within the cytoplasmic tail. Therefore, LSECtin is a pathogen-associated molecular pattern receptor in human myeloid cells. In addition, our results suggest that LSECtin participates in antigen uptake and internalization, and might be a suitable target molecule in vaccination strategies.This work was supported by the Ministerio de Educación y Ciencia (grants SAF2005-0021, AGL2004-02148-ALI, and GEN2003-20649-C06-01/NAC) and Fundación para la Investigación y Prevención del SIDA en Espan˜a (FIPSE 36422/03) to ALC. A.D.S. was supported by a FPI predoctoral grant (BES2004-4405) from Ministerio de Educación y Ciencia (Spain). Authorship Contribution: A.D.S. designed the research and performed the experiments; L.A.F., E.G.M., L.M.P., and P.M. performed the research (lipid raft preparation, thymic cell separation, Ebolabinding assays); M.L.T., M.C., M.Z., R.D., and F.B. provided reagents and supervised individual experiments; and A.L.C. supervised research and wrote the paper.Peer reviewe

Global economic burden of unmet surgical need for appendicitis

Background There is a substantial gap in provision of adequate surgical care in many low- and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially